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Sample records for igf i-stimulated phosphorylation

  1. Binding of IGF I and IGF I-stimulated phosphorylation in canine renal basolateral membranes

    International Nuclear Information System (INIS)

    Hammerman, M.R.; Gavin, J.R. III.

    1986-01-01

    To characterize the interaction of the renal proximal tubular cell with insulin like growth factor I (IGF I), we measured binding of 125 I-IGF I to proximal tubular basolateral membranes from dog kidney and induced IGF I-stimulated phosphorylation of basolateral membranes. Specific binding of 125 I-IGF I to basolateral membranes was observed that was half-maximal at between 10(-9) and 10(-8) M IGF I. 125 I-IGF I was affinity cross-linked to a 135,000 Mr protein in basolateral membranes that was distinct from the alpha-subunit of the insulin receptor and from the IGF II receptor. IGF I-stimulated phosphorylation of a 92,000 Mr protein was effected in detergent-solubilized membranes incubated with 100 microM [gamma- 32 P]ATP. The 32 P-labeled protein was distinct from the beta-subunit of the insulin receptor, the 32 P phosphorylation of which was stimulated by insulin. We conclude that specific receptors for IGF I are present in the basolateral membrane of the renal proximal tubular cell. Physiological actions of IGF I at this nephron site may occur through the binding of this peptide circulating in plasma, to specific basolateral membrane receptors, followed by IGF I stimulated phosphorylation

  2. IGF-I Stimulates Cooperative Interaction between the IGF-I Receptor and CSK Homologous Kinase that Regulates SHPS-1 Phosphorylation in Vascular Smooth Muscle Cells

    Science.gov (United States)

    Radhakrishnan, Yashwanth; Shen, Xinchun; Maile, Laura A.; Xi, Gang

    2011-01-01

    IGF-I plays an important role in smooth muscle cell proliferation and migration. In vascular smooth muscle cells cultured in 25 mm glucose, IGF-I stimulated a significant increase in Src homology 2 domain containing protein tyrosine phosphatase substrate-1 (SHPS-1) phosphorylation compared with 5 mm glucose and this increase was required for smooth muscle cell proliferation. A proteome-wide screen revealed that carboxyl-terminal SRC kinase homologous kinase (CTK) bound directly to phosphotyrosines in the SHPS-1 cytoplasmic domain. Because the kinase(s) that phosphorylates these tyrosines in response to IGF-I is unknown, we determined the roles of IGF-I receptor (IGF-IR) and CTK in mediating SHPS-1 phosphorylation. After IGF-I stimulation, CTK was recruited to IGF-IR and subsequently to phospho-SHPS-1. Expression of an IGF-IR mutant that eliminated CTK binding reduced CTK transfer to SHPS-1, SHPS-1 phosphorylation, and cell proliferation. IGF-IR phosphorylated SHPS-1, which provided a binding site for CTK. CTK recruitment to SHPS-1 resulted in a further enhancement of SHPS-1 phosphorylation. CTK knockdown also impaired IGF-I-stimulated SHPS-1 phosphorylation and downstream signaling. Analysis of specific tyrosines showed that mutation of tyrosines 428/452 in SHPS-1 to phenylalanine reduced SHPS-1 phosphorylation but allowed CTK binding. In contrast, the mutation of tyrosines 469/495 inhibited IGF-IR-mediated the phosphorylation of SHPS-1 and CTK binding, suggesting that IGF-IR phosphorylated Y469/495, allowing CTK binding, and that CTK subsequently phosphorylated Y428/452. Based on the above findings, we conclude that after IGF-I stimulation, CTK is recruited to IGF-IR and its recruitment facilitates CTK's subsequent association with phospho-SHPS-1. This results in the enhanced CTK transfer to SHPS-1, and the two kinases then fully phosphorylate SHPS-1, which is necessary for IGF-I stimulated cellular proliferation. PMID:21799000

  3. Phosphatidylinositol 3-Kinase (PI3K) Activity Bound to Insulin-like Growth Factor-I (IGF-I) Receptor, which Is Continuously Sustained by IGF-I Stimulation, Is Required for IGF-I-induced Cell Proliferation*

    Science.gov (United States)

    Fukushima, Toshiaki; Nakamura, Yusaku; Yamanaka, Daisuke; Shibano, Takashi; Chida, Kazuhiro; Minami, Shiro; Asano, Tomoichiro; Hakuno, Fumihiko; Takahashi, Shin-Ichiro

    2012-01-01

    Continuous stimulation of cells with insulin-like growth factors (IGFs) in G1 phase is a well established requirement for IGF-induced cell proliferation; however, the molecular components of this prolonged signaling pathway that is essential for cell cycle progression from G1 to S phase are unclear. IGF-I activates IGF-I receptor (IGF-IR) tyrosine kinase, followed by phosphorylation of substrates such as insulin receptor substrates (IRS) leading to binding of signaling molecules containing SH2 domains, including phosphatidylinositol 3-kinase (PI3K) to IRS and activation of the downstream signaling pathways. In this study, we found prolonged (>9 h) association of PI3K with IGF-IR induced by IGF-I stimulation. PI3K activity was present in this complex in thyrocytes and fibroblasts, although tyrosine phosphorylation of IRS was not yet evident after 9 h of IGF-I stimulation. IGF-I withdrawal in mid-G1 phase impaired the association of PI3K with IGF-IR and suppressed DNA synthesis the same as when PI3K inhibitor was added. Furthermore, we demonstrated that Tyr1316-X-X-Met of IGF-IR functioned as a PI3K binding sequence when this tyrosine is phosphorylated. We then analyzed IGF signaling and proliferation of IGF-IR−/− fibroblasts expressing exogenous mutant IGF-IR in which Tyr1316 was substituted with Phe (Y1316F). In these cells, IGF-I stimulation induced tyrosine phosphorylation of IGF-IR and IRS-1/2, but mutated IGF-IR failed to bind PI3K and to induce maximal phosphorylation of GSK3β and cell proliferation in response to IGF-I. Based on these results, we concluded that PI3K activity bound to IGF-IR, which is continuously sustained by IGF-I stimulation, is required for IGF-I-induced cell proliferation. PMID:22767591

  4. SP600125 Induces Src and Type I IGF Receptor Phosphorylation Independent of JNK

    Directory of Open Access Journals (Sweden)

    Qingbin Kong

    2014-09-01

    Full Text Available c-Jun N-terminal kinases (JNK are members of the mitogen-activated protein kinase (MAPK family that have important roles in signal transduction. The small molecule SP600125 is widely used in biochemical studies as a JNK inhibitor. However, recent studies indicate that SP600125 may also act independent of JNK. Here, we report that SP600125 can induce Src, type I insulin-like growth factor receptor (IGF-IR, Akt and Erk1/2 phosphorylation. Notably, these effects are independent of its inhibition of JNK. Inhibition of Src abrogates the stimulation of IGF-IR, Akt and Erk1/2 phosphorylation. IGF-IR knockdown blunts the induction of both Akt and Erk1/2 phosphorylation by SP600125. Moreover, combination of SP600125 and the Src inhibitor saracatinib synergistically inhibits cell proliferation. We conclude that SP600125 can activate Src-IGF-IR-Akt/Erk1/2 signaling pathways independent of JNK.

  5. IGF-I, IGF-II, and Insulin Stimulate Different Gene Expression Responses through Binding to the IGF-I Receptor

    DEFF Research Database (Denmark)

    Versteyhe, Soetkin; Klaproth, Birgit; Borup, Rehannah

    2013-01-01

    Insulin and the insulin-like growth factors (IGF)-I and -II are closely related peptides important for regulation of metabolism, growth, differentiation, and development. The IGFs exert their main effects through the IGF-I receptor. Although the insulin receptor is the main physiological receptor...... for insulin, this peptide hormone can also bind at higher concentrations to the IGF-I receptor and exert effects through it. We used microarray gene expression profiling to investigate the gene expression regulated by IGF-I, IGF-II, and insulin after stimulation of the IGF-I receptor. Fibroblasts from mice......, knockout for IGF-II and the IGF-II/cation-independent mannose-6-phosphate receptor, and expressing functional IGF-I but no insulin receptors, were stimulated for 4 h with equipotent saturating concentrations of insulin, IGF-I, and IGF-II. Each ligand specifically regulated a group of transcripts...

  6. IGF-I stimulates ERβ and aromatase expression via IGF1R/PI3K/AKT-mediated transcriptional activation in endometriosis.

    Science.gov (United States)

    Zhou, Yan; Zeng, Cheng; Li, Xin; Wu, Pei-Li; Yin, Ling; Yu, Xiao-Lan; Zhou, Ying-Fang; Xue, Qing

    2016-08-01

    Estrogen receptor beta (ERβ, encoded by ESR2 gene) and cytochrome P450 aromatase (encoded by CYP19A1 gene) play critical roles in endometriosis, and the levels of insulin-like growth factor-I (IGF-I) in the peritoneal fluid are significantly higher in patients with endometriosis compared with those in normal women. However, the effects and mechanisms of IGF-I on ERβ and aromatase expression remain to be fully elucidated. In this study, human endometriotic stromal cells (ESCs) and endometrial cells (EMs) derived from ovarian endometriomas and eutopic endometrial tissues. ESCs were cultured with IGF-I, signal pathway inhibitors, and siRNAs. ERβ and aromatase expression were measured by real-time PCR and Western, respectively. The binding of c-Jun and CREB to the ESR2 and CYP19A1 promoters was assessed by chromatin immunoprecipitation assay. Animal experiments were performed in a xenograft mouse model. Levels of IGF-I mRNA in ESCs were markedly higher than those in EMs. IGF-I upregulated ERβ and aromatase expression in ESCs after stimulation of the IGF1R/PI3K/AKT pathway. Following IGF-I treatment, a marked increase in c-Jun and CREB phosphorylation occurred, enhancing binding to the ESR2 and CYP19A1 promoters. An IGF1R inhibitor in vivo reduced IGF-I-induced endometriosis graft growth and ERβ and aromatase expression. In conclusion, this is the first report to describe a mechanistic analysis of ERβ and aromatase expression regulated by IGF-I in ESCs. Moreover, an IGF1R inhibitor impeded ectopic lesion growth in nude mice. These findings suggest that an inhibitor of IGF1R might have therapeutic potential as an antiendometriotic drug. Level of IGF-I mRNA in ESCs is markedly higher than that in EMs. IGF-I up-regulates ERβ and aromatase expression via IGF1R/PI3K/AKT pathway. C-Jun and CREB are recruited to ESR2 or CYP19A1 promoter by IGF-I stimulation. IGF-1R inhibitors in vivo impede the growth of ectopic lesions in nude mice.

  7. Role of IGF-I in follistatin-induced skeletal muscle hypertrophy.

    Science.gov (United States)

    Barbé, Caroline; Kalista, Stéphanie; Loumaye, Audrey; Ritvos, Olli; Lause, Pascale; Ferracin, Benjamin; Thissen, Jean-Paul

    2015-09-15

    Follistatin, a physiological inhibitor of myostatin, induces a dramatic increase in skeletal muscle mass, requiring the type 1 IGF-I receptor/Akt/mTOR pathway. The aim of the present study was to investigate the role of IGF-I and insulin, two ligands of the IGF-I receptor, in the follistatin hypertrophic action on skeletal muscle. In a first step, we showed that follistatin increases muscle mass while being associated with a downregulation of muscle IGF-I expression. In addition, follistatin retained its full hypertrophic effect toward muscle in hypophysectomized animals despite very low concentrations of circulating and muscle IGF-I. Furthermore, follistatin did not increase muscle sensitivity to IGF-I in stimulating phosphorylation of Akt but, surprisingly, decreased it once hypertrophy was present. Taken together, these observations indicate that increased muscle IGF-I production or sensitivity does not contribute to the muscle hypertrophy caused by follistatin. Unlike low IGF-I, low insulin, as obtained by streptozotocin injection, attenuated the hypertrophic action of follistatin on skeletal muscle. Moreover, the full anabolic response to follistatin was restored in this condition by insulin but also by IGF-I infusion. Therefore, follistatin-induced muscle hypertrophy requires the activation of the insulin/IGF-I pathway by either insulin or IGF-I. When insulin or IGF-I alone is missing, follistatin retains its full anabolic effect, but when both are deficient, as in streptozotocin-treated animals, follistatin fails to stimulate muscle growth. Copyright © 2015 the American Physiological Society.

  8. Lycopene inhibits IGF-I signal transduction and growth in normal prostate epithelial cells by decreasing DHT-modulated IGF-I production in co-cultured reactive stromal cells.

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    Liu, Xunxian; Allen, Jeffrey D; Arnold, Julia T; Blackman, Marc R

    2008-04-01

    Prostate stromal and epithelial cell communication is important in prostate functioning and cancer development. Primary human stromal cells from normal prostate stromal cells (PRSC) maintain a smooth muscle phenotype, whereas those from prostate cancer (6S) display reactive and fibroblastic characteristics. Dihydrotestosterone (DHT) stimulates insulin-like growth factor-I (IGF-I) production by 6S but not PSRC cells. Effects of reactive versus normal stroma on normal human prostate epithelial (NPE or PREC) cells are poorly understood. We co-cultured NPE plus 6S or PRSC cells to compare influences of different stromal cells on normal epithelium. Because NPE and PREC cells lose androgen receptor (AR) expression in culture, DHT effects must be modulated by associated stromal cells. When treated with camptothecin (CM), NPE cells, alone and in stromal co-cultures, displayed a dose-dependent increase in DNA fragmentation. NPE/6S co-cultures exhibited reduced CM-induced cell death with exposure to DHT, whereas NPE/PRSC co-cultures exhibited CM-induced cell death regardless of DHT treatment. DHT blocked CM-induced, IGF-I-mediated, NPE death in co-cultured NPE/6S cells without, but not with, added anti-IGF-I and anti-IGF-R antibodies. Lycopene consumption is inversely related to human prostate cancer risk and inhibits IGF-I and androgen signaling in rat prostate cancer. In this study, lycopene, in dietary concentrations, reversed DHT effects of 6S cells on NPE cell death, decreased 6S cell IGF-I production by reducing AR and beta-catenin nuclear localization and inhibited IGF-I-stimulated NPE and PREC growth, perhaps by attenuating IGF-I's effects on serine phosphorylation of Akt and GSK3beta and tyrosine phosphorylation of GSK3. This study expands the understanding of the preventive mechanisms of lycopene in prostate cancer.

  9. IGF-II receptors and IGF-II-stimulated glucose transport in human fat cells

    International Nuclear Information System (INIS)

    Sinha, M.K.; Buchanan, C.; Raineri-Maldonado, C.; Khazanie, P.; Atkinson, S.; DiMarchi, R.; Caro, J.F.

    1990-01-01

    Insulin-like growth factor II (IGF-II) receptors have been described in rat but not in human adipocytes. In both species, IGF-II has been reported to stimulate glucose transport by interacting with the insulin receptor. In this study, we have unequivocally demonstrated the presence of IGF-II receptors in human adipocytes. 125I-labeled IGF-II specifically binds to intact adipocytes, membranes, and lectin-purified detergent solubilized extracts. Through the use of 0.5 mM disuccinimidyl suberate, 125I-IGF-II is cross-linked to a 260-kDa protein that is identified as the IGF-II receptor by displacement experiments with unlabeled IGF-II, IGF-I, and insulin and either by immunoprecipitation or by Western blot analysis with mannose 6-phosphate receptor antibodies. The concentrations of IGF-II required for half-maximal and maximal stimulation of glucose transport in human adipocytes are 35 and 100 times more than that of insulin. The possibility of IGF-II stimulating glucose transport by interacting predominantly with the insulin receptor is suggested by the following: (1) the concentration of IGF-II that inhibits half of insulin binding is only 20 times more than that of insulin; (2) the lack of an additive effect of IGF-II and insulin for maximal stimulation of glucose transport; (3) the ability of monoclonal insulin receptor antibodies to decrease glucose transport stimulated by submaximal concentrations of both IGF-II and insulin; and (4) the ability of IGF-II to stimulate insulin receptor autophosphorylation albeit at a reduced potency when compared with insulin

  10. Stimulation of proteoglycans by IGF I and II in microvessel and large vessel endothelial cells

    International Nuclear Information System (INIS)

    Bar, R.S.; Dake, B.L.; Stueck, S.

    1987-01-01

    Endothelial cells were cultured from bovine capillaries and pulmonary arteries, and the effect of insulinlike growth factor (IGF) I and II (multiplication-stimulating activity) and insulin on the synthesis of proteoglycans was determined. IGF I and II stimulated 35 SO 4 incorporation into proteoglycans in a dose-dependent manner in both microvessel and pulmonary artery endothelial cells with maximum threefold increases. In pulmonary artery cells, the IGFs caused a general stimulation of all classes of glycosaminoglycan-containing proteoglycans. In microvessel endothelial cells, the IGFs appeared to preferentially increase heparan sulfate-containing proteoglycans. Insulin, at concentrations up to 10 -6 M, had no effect on the synthesis of proteoglycans in either microvessel or pulmonary arterial endothelial cells. Thus, the IGFs stimulate the synthesis of proteoglycans in both microvessel and large vessel endothelial cells, a property that is not mimicked by insulin. Because vascular endothelial cells are bathed by IGFs in vivo, such IGF-mediated functions are likely to be significant in both the normal physiology of vascular endothelium and in disease states such as diabetes mellitus

  11. The proto-oncogene product c-Crk associates with insulin receptor substrate-1 and 4PS. Modulation by insulin growth factor-I (IGF) and enhanced IGF-I signaling.

    Science.gov (United States)

    Beitner-Johnson, D; Blakesley, V A; Shen-Orr, Z; Jimenez, M; Stannard, B; Wang, L M; Pierce, J; LeRoith, D

    1996-04-19

    The Crk proto-oncogene product is an SH2 and SH3 domain-containing adaptor protein which we have previously shown to become rapidly tyrosine phosphorylated in response to stimulation with insulin-like growth factor I (IGF-I) in NIH-3T3 cells. In order to further characterize the role of Crk in the IGF-I signaling pathway, NIH-3T3 and 293 cells were stably transfected with an expression vector containing the Crk cDNA. The various resultant 3T3-Crk clones expressed Crk at approximately 2-15-fold higher levels than parental 3T3 cells. In 3T3-Crk cells, Crk immunoreactivity was detected in insulin receptor substrate-1 (IRS-1) immunoprecipitates. Stimulation with IGF-I resulted in a dissociation of Crk protein from IRS-1. In contrast, the association of the related adaptor protein Grb2 with IRS-1 was enhanced by IGF-I stimulation. Similar results were obtained in stably transfected 293-Crk cells, which express both IRS-1 and the IRS-1-related signaling protein 4PS. In these cells, IRS-1 and 4PS both associated with Crk, and this association was also decreased by IGF-I treatment, whereas the association of Grb2 with IRS-1 and 4PS was enhanced by IGF-I. Overexpression of Crk also enhanced IGF-I-induced mitogenesis of NIH-3T3 cells, as measured by [3H]thymidine incorporation. The levels of IGF-I-induced mitogenesis were proportional to the level of Crk expression. These results suggest that Crk is a positive effector of IGF-I signaling, and may mediate its effects via interaction with IRS-1 and/or 4PS.

  12. PKC{eta} is a negative regulator of AKT inhibiting the IGF-I induced proliferation

    Energy Technology Data Exchange (ETDEWEB)

    Shahaf, Galit; Rotem-Dai, Noa; Koifman, Gabriela; Raveh-Amit, Hadas; Frost, Sigal A.; Livneh, Etta, E-mail: etta@bgu.ac.il

    2012-04-15

    The PI3K-AKT pathway is frequently activated in human cancers, including breast cancer, and its activation appears to be critical for tumor maintenance. Some malignant cells are dependent on activated AKT for their survival; tumors exhibiting elevated AKT activity show sensitivity to its inhibition, providing an Achilles heel for their treatment. Here we show that the PKC{eta} isoform is a negative regulator of the AKT signaling pathway. The IGF-I induced phosphorylation on Ser473 of AKT was inhibited by the PKC{eta}-induced expression in MCF-7 breast adenocarcinoma cancer cells. This was further confirmed in shRNA PKC{eta}-knocked-down MCF-7 cells, demonstrating elevated phosphorylation on AKT Ser473. While PKC{eta} exhibited negative regulation on AKT phosphorylation it did not alter the IGF-I induced ERK phosphorylation. However, it enhanced ERK phosphorylation when stimulated by PDGF. Moreover, its effects on IGF-I/AKT and PDGF/ERK pathways were in correlation with cell proliferation. We further show that both PKC{eta} and IGF-I confer protection against UV-induced apoptosis and cell death having additive effects. Although the protective effect of IGF-I involved activation of AKT, it was not affected by PKC{eta} expression, suggesting that PKC{eta} acts through a different route to increase cell survival. Hence, our studies show that PKC{eta} provides negative control on AKT pathway leading to reduced cell proliferation, and further suggest that its presence/absence in breast cancer cells will affect cell death, which could be of therapeutic value.

  13. Monoclonal antibody to the type I insulin-like growth factor (IGF-I) receptor blocks IGF-I receptor-mediated DNA synthesis: clarification of the mitogenic mechanisms of IGF-I and insulin in human skin fibroblasts

    International Nuclear Information System (INIS)

    Flier, J.S.; Usher, P.; Moses, A.C.

    1986-01-01

    Insulin and insulin-like growth factor type I (IGF-I) stimulate an overlapping spectrum of biological responses in human skin fibroblasts. Although insulin and IGF-I are known to stimulate the incorporation of [ 3 H]thymidine into DNA in these cells, the identify of the receptor(s) that mediates this effect has not been fully clarified. The mouse anti-human IGF-I receptor antibody αIR-3 binds with specificity to IGF-I but not to insulin receptors in human placental membranes; it also specifically inhibits the binding of 125 I-labeled IGF-I but not 125 I-labeled insulin to suspensions of human skin fibroblasts in a dose-dependent manner. αIR-3 competitively inhibits IGF-I-mediated stimulation of [ 3 H]thymidine incorporation into DNA. This inhibition is dependent on the concentration of αIR-3 and in the presence of a fixed antibody concentration can be partially overcome by high concentrations of IGF-I. In contrast, at concentrations of 3 H]thymidine incorporation is not inhibited by αIR-3. However, the incremental effects of higher concentrations (> 1 μg/ml) of insulin on [ 3 H]thymidine incorporation are inhibited by αIR-3. αIR-3 is a highly specific antagonist of IGF-I receptor-mediated mitogenesis in human skin fibroblasts. By using this antibody, it is shown directly that insulin can act through the IGF-I receptor to stimulate DNA synthesis but can also activate this effect through the insulin receptor itself

  14. Identification of Compounds That Inhibit IGF-I Signaling in Hyperglycemia

    Directory of Open Access Journals (Sweden)

    Laura A. Maile

    2009-01-01

    Full Text Available Increased responsiveness of vascular cells to the growth factor IGF-I has been implicated in complications associated with diabetes. Here we describe the development of an assay and screening of a library of compounds for their ability to accelerate cleavage of the transmembrane protein integrin-associated protein (IAP thereby disrupting the association between IAP and SHPS-1 which we have shown as critical for the enhanced response of vascular cells to IGF-I. The cell-based ELISA utilizes an antibody that specifically detects cleaved, but not intact, IAP. Of the 1040 compounds tested, 14 were considered active by virtue of their ability to stimulate an increase in antibody-binding indicative of IAP cleavage. In experiments with smooth muscle and retinal endothelial cell cultures in hyperglycemic conditions, each active compound was shown to accelerate the cleavage of IAP, and this was associated with a decrease in IAP association with SHPS-1 as determined by coimmunoprecipitation of the proteins from cell lysates. As a consequence of the acceleration in IAP cleavage, the compounds were shown to inhibit IGF-I-stimulated phosphorylation of key signaling molecules including Shc and ERK1/2, and this in turn was associated with a decrease in IGF-I-stimulated cell proliferation. Identification of these compounds that utilize this mechanism has the potential to yield novel therapeutic approaches for the prevention and treatment of vascular complications associated with diabetes.

  15. Mechanical Stimulation and IGF-1 Enhance mRNA Translation Rate in Osteoblasts Via Activation of the AKT-mTOR Pathway.

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    Bakker, Astrid D; Gakes, Tom; Hogervorst, Jolanda M A; de Wit, Gerard M J; Klein-Nulend, Jenneke; Jaspers, Richard T

    2016-06-01

    Insulin-like growth factor-1 (IGF-1) is anabolic for muscle by enhancing the rate of mRNA translation via activation of AKT and subsequent activation of the mammalian target of rapamycin complex 1 (mTOR), thereby increasing cellular protein production. IGF-1 is also anabolic for bone, but whether the mTOR pathway plays a role in the rate of bone matrix protein production by osteoblasts is unknown. We hypothesized that anabolic stimuli such as mechanical loading and IGF-1 stimulate protein synthesis in osteoblasts via activation of the AKT-mTOR pathway. MC3T3-E1 osteoblasts were either or not subjected for 1 h to mechanical loading by pulsating fluid flow (PFF) or treated with or without human recombinant IGF-1 (1-100 ng/ml) for 0.5-6 h, to determine phosphorylation of AKT and p70S6K (downstream of mTOR) by Western blot. After 4 days of culture with or without the mTOR inhibitor rapamycin, total protein, DNA, and gene expression were quantified. IGF-1 (100 ng/ml) reduced IGF-1 gene expression, although PFF enhanced IGF-1 expression. IGF-1 did not affect collagen-I gene expression. IGF-1 dose-dependently enhanced AKT and p70S6K phosphorylation at 2 and 6 h. PFF enhanced phosphorylation of AKT and p70S6K already within 1 h. Both IGF-1 and PFF enhanced total protein per cell by ∼30%, but not in the presence of rapamycin. Our results show that IGF-1 and PFF activate mTOR, thereby stimulating the rate of mRNA translation in osteoblasts. The known anabolic effect of mechanical loading and IGF-1 on bone may thus be partly explained by mTOR-mediated enhanced protein synthesis in osteoblasts. © 2015 Wiley Periodicals, Inc.

  16. Serum insulin-like growth factor I (IGF-I) and IGF-binding protein 3 levels are increased in central precocious puberty

    DEFF Research Database (Denmark)

    Juul, A; Scheike, Thomas Harder; Nielsen, C T

    1995-01-01

    between IGF-I and IGFBP-3 (i.e. free biologically active IGF-I) declined concomitantly with a decrease in growth velocity. Serum levels of IGF-I and IGFBP-3 (expressed as the SD score for bone age), but not those of estradiol, correlated with height velocity before and during treatment (r = 0.34; P ...Central precocious puberty (CPP) is characterized by early activation of the pituitary-gonadal axis, which leads to increased growth velocity and development of secondary sexual characteristics. It is generally believed that gonadal sex steroids stimulate pulsatile GH secretion, which, in turn......, stimulates insulin-like growth factor I (IGF-I) and IGF-binding protein 3 (IGFBP-3) production. However, little is known about GH, IGF-I, and IGFBP-3 serum levels in children with precocious puberty. Treatment of CPP by GnRH agonists has become the treatment of choice. However, the effect of long term...

  17. Distribution of IGF receptors in the plasma membrane of proximal tubular cells

    International Nuclear Information System (INIS)

    Hammerman, M.R.; Rogers, S.

    1987-01-01

    To characterize the distribution of receptors for insulin-like growth factors I and II (IGF I and II) in the plasma membrane of the renal proximal tubular cell, the authors measured binding of 125 I-labeled IGF I and 125 I-labeled IGF II to proximal tubular basolateral and brush-border membranes and characterized IGF I-stimulated phosphorylation of detergent-solubilized membranes. 125 I-IGF bound primarily to a 135,000 relative molecular weight (M r ) protein and IGF II to a 260,000 M r protein in isolated membranes. Binding of 125 I-IGF I was severalfold greater in basolateral than in brush-border membranes. IGF I-stimulated phosphorylation of the 92,000 M r β-subunit of its receptors could be demonstrated only in basolateral membranes. These findings are consistent with an asymmetrical distribution of receptors for IGF I in the plasma membrane of the renal proximal tubular cell, localization being primary on the basolateral side. In contrast, binding of 125 I-IGF II to isolated basolateral and brush-border membranes was equivalent, suggesting that receptors for this peptide are distributed more symmetrically in the plasma membrane. The findings suggest that the action of IGF I in proximal tubule are mediated via interaction of circulating peptide with specific receptors in the basolateral membrane. However, the findings established the potential for actions of IGF II to be exerted in proximal tubule via interaction with both basolateral and/or brush-border membrane receptors

  18. Serum insulin-like growth factor I (IGF-I) and IGF-binding protein 3 levels are increased in central precocious puberty

    DEFF Research Database (Denmark)

    Juul, A; Scheike, Thomas Harder; Nielsen, C T

    1995-01-01

    Central precocious puberty (CPP) is characterized by early activation of the pituitary-gonadal axis, which leads to increased growth velocity and development of secondary sexual characteristics. It is generally believed that gonadal sex steroids stimulate pulsatile GH secretion, which, in turn......, stimulates insulin-like growth factor I (IGF-I) and IGF-binding protein 3 (IGFBP-3) production. However, little is known about GH, IGF-I, and IGFBP-3 serum levels in children with precocious puberty. Treatment of CPP by GnRH agonists has become the treatment of choice. However, the effect of long term...

  19. Research resource: new and diverse substrates for the insulin receptor isoform a revealed by quantitative proteomics after stimulation with igf-ii or insulin

    DEFF Research Database (Denmark)

    Morcavallo, Alaide; Gaspari, Marco; Pandini, Giuseppe

    2011-01-01

    progression. We hypothesized that IGF-II binding to the IR-A elicits a unique signaling pathway. In order to obtain an unbiased evaluation of IR-A substrates differentially involved after IGF-II and insulin stimulation, we performed quantitative proteomics of IR-A substrates recruited to tyrosine......-phosphorylated protein complexes using stable isotope labeling with amino acids in cell culture in combination with antiphosphotyrosine antibody pull down and mass spectrometry. Using cells expressing only the human IR-A and lacking the IGF-I receptor, we identified 38 IR-A substrates. Only 10 were known IR mediators......, whereas 28 substrates were not previously related to IR signaling. Eleven substrates were recruited by stimulation with both ligands: two equally recruited by IGF-II and insulin, three more strongly recruited by IGF-II, and six more strongly recruited by insulin. Moreover, 14 substrates were recruited...

  20. Structural analysis of the interaction of IGF I with the IGF types 1 and 2 and insulin receptors

    International Nuclear Information System (INIS)

    Cascieri, M.A.; Chicchi, G.G.; Hayes, N.S.; Green, B.G.; Applebaum, J.A.; Bayne, M.L.

    1987-01-01

    A synthetic gene for human IGF I has been synthesized which directs the synthesis and secretion of fully active human IGF I (rIGF I) from yeast. rIGF I inhibits binding of 125 I-IGF I to type 1 IGF receptors from human placenta (IGF-R1, IC50 = 4 nM), binding of 125 I-insulin to insulin receptors (IR, IC50 = 881 nM), binding of 125 I-MSA to type 2 IGF receptors from rat liver (IGF-R2, IC50 = 80 nM), and binding of 125 I-IGF I to crude human serum binding protein (hBP, IC50 = 0.42 nM). rIGF I is equipotent to human IGF I in stimulating glucose transport in murine BC3H1 cells and in stimulating DNA synthesis in rat A10 cells. Site directed mutagenesis of the synthetic gene is being used to characterize the structural requirements for binding to these receptors. IGF I (FFY) B(23-25) is equipotent to rIGF I at the IGF-R1 (6.9 nM), the IGF-R2 (36 nM), and the IR (841 nM) and is less potent at the hBP (1.7 nM). In contrast, IGF I(SFY) B(23-25) is 20-fold less potent than rIGF I at the IGF-R1 and is 10-fold less potent than rIGF I at hBP. This peptide is greater than 10-fold less active at the IGF-R2 and the IR. This peptide is a full agonist in the cell assays but 20-50 fold less potent than rIGF I. These data are consistent with the hypothesis that the F to S change destabilizes the tertiary structure of IGF I

  1. Novel cross-talk between IGF-IR and DDR1 regulates IGF-IR trafficking, signaling and biological responses

    Science.gov (United States)

    Sacco, Antonella; Morcavallo, Alaide; Vella, Veronica; Voci, Concetta; Spatuzza, Michela; Xu, Shi-Qiong; Iozzo, Renato V.; Vigneri, Riccardo; Morrione, Andrea; Belfiore, Antonino

    2015-01-01

    The insulin-like growth factor-I receptor (IGF-IR), plays a key role in regulating mammalian development and growth, and is frequently deregulated in cancer contributing to tumor initiation and progression. Discoidin domain receptor 1 (DDR1), a collagen receptor tyrosine-kinase, is as well frequently overexpressed in cancer and implicated in cancer progression. Thus, we investigated whether a functional cross-talk between the IGF-IR and DDR1 exists and plays any role in cancer progression. Using human breast cancer cells we found that DDR1 constitutively associated with the IGF-IR. However, this interaction was enhanced by IGF-I stimulation, which promoted rapid DDR1 tyrosine-phosphorylation and co-internalization with the IGF-IR. Significantly, DDR1 was critical for IGF-IR endocytosis and trafficking into early endosomes, IGF-IR protein expression and IGF-I intracellular signaling and biological effects, including cell proliferation, migration and colony formation. These biological responses were inhibited by DDR1 silencing and enhanced by DDR1 overexpression. Experiments in mouse fibroblasts co-transfected with the human IGF-IR and DDR1 gave similar results and indicated that, in the absence of IGF-IR, collagen-dependent phosphorylation of DDR1 is impaired. These results demonstrate a critical role of DDR1 in the regulation of IGF-IR action, and identify DDR1 as a novel important target for breast cancers that overexpress IGF-IR. PMID:25840417

  2. Insulin and insulin-like growth factor-I (IGF-I) receptor phosphorylation in µ-calpain knockout mice

    Science.gov (United States)

    Numerous cellular processes are controlled by insulin and IGF-I signaling pathways. Due to previous work in our laboratories, we hypothesized that insulin (IR) and type 1 IGF-I (IGF-IR) receptor signaling is decreased due to increased protein tyrosine phosphatase 1B (PTP1B) activity. C57BL/6J mice...

  3. HSF1 phosphorylation by ERK/GSK3 suppresses RNF126 to sustain IGF-IIR expression for hypertension-induced cardiomyocyte hypertrophy.

    Science.gov (United States)

    Huang, Chih-Yang; Lee, Fa-Lun; Peng, Shu-Fen; Lin, Kuan-Ho; Chen, Ray-Jade; Ho, Tsung-Jung; Tsai, Fu-Jen; Padma, Vijaya V; Kuo, Wei-Wen; Huang, Chih-Yang

    2018-02-01

    Hypertension-induced cardiac hypertrophy and apoptosis are major characteristics of early-stage heart failure (HF). Inhibition of extracellular signal-regulated kinases (ERK) efficaciously suppressed angiotensin II (ANG II)-induced cardiomyocyte hypertrophy and apoptosis by blocking insulin-like growth factor II receptor (IGF-IIR) signaling. However, the detailed mechanism by which ANG II induces ERK-mediated IGF-IIR signaling remains elusive. Here, we found that ANG II activated ERK to upregulate IGF-IIR expression via the angiotensin II type I receptor (AT 1 R). ERK activation subsequently phosphorylates HSF1 at serine 307, leading to a secondary phosphorylation by glycogen synthase kinase III (GSK3) at serine 303. Moreover, we found that ANG II mediated ERK/GSK3-induced IGF-IIR protein stability by downregulating the E3 ubiquitin ligase of IGF-IIR RING finger protein CXXVI (RNF126). The expression of RNF126 decreased following ANG II-induced HSF1 S303 phosphorylation, resulting in IGF-IIR protein stability and increased cardiomyocyte injury. Inhibition of GSK3 significantly alleviated ANG II-induced cardiac hypertrophy in vivo and in vitro. Taken together, these results suggest that HSF1 phosphorylation stabilizes IGF-IIR protein stability by downregulating RNF126 during cardiac hypertrophy. ANG II activates ERK/GSK3 to phosphorylate HSF1, resulting in RNF126 degradation, which stabilizes IGF-IIR protein expression and eventually results in cardiac hypertrophy. HSF1 could be a valuable therapeutic target for cardiac diseases among hypertensive patients. © 2017 Wiley Periodicals, Inc.

  4. DA Negatively Regulates IGF-I Actions Implicated in Cognitive Function via Interaction of PSD95 and nNOS in Minimal Hepatic Encephalopathy.

    Science.gov (United States)

    Ding, Saidan; Zhuge, Weishan; Wang, Xuebao; Yang, Jianjing; Lin, Yuanshao; Wang, Chengde; Hu, Jiangnan; Zhuge, Qichuan

    2017-01-01

    Insulin-like growth factor I (IGF-I) has been positively correlated with cognitive ability. Cognitive decline in minimal hepatic encephalopathy (MHE) was shown to be induced by elevated intracranial dopamine (DA). The beneficial effect of IGF-I signaling in MHE remains unknown. In this study, we found that IGF-I content was reduced in MHE rats and that IGF-I administration mitigated cognitive decline of MHE rats. A protective effect of IGF-I on the DA-induced interaction between postsynaptic density protein 95 (PSD95) and neuronal nitric oxide synthase (nNOS) was found in neurons. Ribosomal S6 protein kinase (RSK) phosphorylated nNOS in response to IGF-I by recruiting extracellular signal-regulated kinase (ERK1/2). In turn, DA inactivated the ERK1/2/RSK pathway and stimulated the PSD95-nNOS interaction by downregulating IGF-I. Inhibition of the interaction between PSD95 and nNOS ameliorated DA-induced memory impairment. As DA induced deficits in the ERK1/2/RSK pathway and the interaction between PSD95 and nNOS in MHE brains, IGF-I administration exerted a protective effect via interruption of the interaction between PSD95 and nNOS. These results suggest that IGF-I antagonizes DA-induced cognitive loss by disrupting PSD95-nNOS interactions in MHE.

  5. DA Negatively Regulates IGF-I Actions Implicated in Cognitive Function via Interaction of PSD95 and nNOS in Minimal Hepatic Encephalopathy

    Directory of Open Access Journals (Sweden)

    Saidan Ding

    2017-09-01

    Full Text Available Insulin-like growth factor I (IGF-I has been positively correlated with cognitive ability. Cognitive decline in minimal hepatic encephalopathy (MHE was shown to be induced by elevated intracranial dopamine (DA. The beneficial effect of IGF-I signaling in MHE remains unknown. In this study, we found that IGF-I content was reduced in MHE rats and that IGF-I administration mitigated cognitive decline of MHE rats. A protective effect of IGF-I on the DA-induced interaction between postsynaptic density protein 95 (PSD95 and neuronal nitric oxide synthase (nNOS was found in neurons. Ribosomal S6 protein kinase (RSK phosphorylated nNOS in response to IGF-I by recruiting extracellular signal-regulated kinase (ERK1/2. In turn, DA inactivated the ERK1/2/RSK pathway and stimulated the PSD95–nNOS interaction by downregulating IGF-I. Inhibition of the interaction between PSD95 and nNOS ameliorated DA-induced memory impairment. As DA induced deficits in the ERK1/2/RSK pathway and the interaction between PSD95 and nNOS in MHE brains, IGF-I administration exerted a protective effect via interruption of the interaction between PSD95 and nNOS. These results suggest that IGF-I antagonizes DA-induced cognitive loss by disrupting PSD95–nNOS interactions in MHE.

  6. Cell surface GRP78 facilitates hepatoma cells proliferation and migration by activating IGF-IR.

    Science.gov (United States)

    Yin, Yancun; Chen, Chen; Chen, Jinliang; Zhan, Renhui; Zhang, Qiang; Xu, Xiaoyan; Li, Defang; Li, Minjing

    2017-07-01

    The 78kDa glucose regulated protein (GRP78) is a multifunctional chaperone that is involved in a variety of cellular processes. Insulin like growth factor I receptor (IGF-IR) often aberrant expresses in many types of tumor cells. The IGF-IR signaling plays key roles in carcinogenesis and maintenance of the malignant phenotype. The crosstalk between GRP78 and IGF-IR molecules has not well been illuminated. Here, we demonstrated a reciprocal regulation of GRP78 expression and IGF-IR pathway activation. IGF-I induced GRP78 expression in hepatoma cells. IGF-IR knockdown or IGF-IR inhibitor repressed GRP78 expression. Both phosphatidylinositol 3-kianase (PI3K) and mitogen-activated protein kinase (MAPK) pathways involved in IGF-I induction of GRP78 expression. Interestingly, treatment of hepatoma cells with IGF-I re-distributes GRP78 from endoplasmic reticulum (ER) to cell surface and promotes its physical interaction with IGF-IR. Also, GRP78 promotes IGF-IR phosphorylation and activation. Blocked of GRP78 by small interfering RNA or inhibition of GRP78 function by (-)-epigallocatechin gallate (EGCG) blocks IGF-I induced IGF-IR phosphorylation and its downstream signaling. Further, blocked cell surface GRP78 with antibody inhibits IGF-I stimulated cellular proliferation and migration. These data reveal an essential role for the molecular chaperone GRP78 in IGF-IR signaling and implicate the use of GRP78 inhibitors in blocking IGF-IR signaling in hepatoma cells. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Insulin-like growth factor (IGF) binding protein from human decidua inhibits the binding and biological action of IGF-I in cultured choriocarcinoma cells

    International Nuclear Information System (INIS)

    Ritvos, O.; Ranta, T.; Jalkanen, J.; Suikkari, A.M.; Voutilainen, R.; Bohn, H.; Rutanen, E.M.

    1988-01-01

    The placenta expresses genes for insulin-like growth factors (IGFs) and possesses IGF-receptors, suggesting that placental growth is regulated by IGFs in an autocrine manner. We have previously shown that human decidua, but not placenta, synthesizes and secretes a 34 K IGF-binding protein (34 K IGF-BP) called placental protein 12. We now used human choriocarcinoma JEG-3 cell monolayer cultures and recombinant (Thr59)IGF-I as a model to study whether the decidual 34 K IGF-BP is able to modulate the receptor binding and biological activity of IGFs in trophoblasts. JEG-3 cells, which possess type I IGF receptors, were unable to produce IGF-BPs. Purified 34 K IGF-BP specifically bound [125I]iodo-(Thr59)IGF-I. Multiplication-stimulating activity had 2.5% the potency of (Thr59)IGF-I, and insulin had no effect on the binding of [125I] iodo-(Thr59)IGF-I. 34 K IGF-BP inhibited the binding of [125I] iodo-(Thr59)IGF-I to JEG-3 monolayers in a concentration-dependent manner by forming with the tracer a soluble complex that could not bind to the cell surface as demonstrated by competitive binding and cross-linking experiments. After incubating the cell monolayers with [125I]iodo-(Thr59)IGF-I in the presence of purified binding protein, followed by cross-linking, no affinity labeled bands were seen on autoradiography. In contrast, an intensely labeled band at 40 K was detected when the incubation medium was analyzed, suggesting that (Thr59)IGF-I and 34 K IGF-BP formed a complex in a 1:1 molar ratio. Also, 34 K IGF-BP inhibited both basal and IGF-I-stimulated uptake of alpha-[3H]aminoisobutyric acid in JEG-3 cells. RNA analysis revealed that IGF-II is expressed in JEG-3 cells

  8. IGF1 stimulates greater muscle hypertrophy in the absence of myostatin in male mice.

    Science.gov (United States)

    Hennebry, Alexander; Oldham, Jenny; Shavlakadze, Tea; Grounds, Miranda D; Sheard, Philip; Fiorotto, Marta L; Falconer, Shelley; Smith, Heather K; Berry, Carole; Jeanplong, Ferenc; Bracegirdle, Jeremy; Matthews, Kenneth; Nicholas, Gina; Senna-Salerno, Mônica; Watson, Trevor; McMahon, Christopher D

    2017-08-01

    Insulin-like growth factors (IGFs) and myostatin have opposing roles in regulating the growth and size of skeletal muscle, with IGF1 stimulating, and myostatin inhibiting, growth. However, it remains unclear whether these proteins have mutually dependent, or independent, roles. To clarify this issue, we crossed myostatin null ( Mstn -/- ) mice with mice overexpressing Igf1 in skeletal muscle ( Igf1 + ) to generate six genotypes of male mice; wild type ( Mstn +/+ ), Mstn +/- , Mstn -/- , Mstn +/+ :Igf1 + , Mstn +/- :Igf1 + and Mstn -/- :Igf1 + Overexpression of Igf1 increased the mass of mixed fibre type muscles (e.g. Quadriceps femoris ) by 19% over Mstn +/+ , 33% over Mstn +/- and 49% over Mstn -/- ( P  Myostatin regulated the number, while IGF1 regulated the size of myofibres, and the deletion of Mstn and Igf1 + independently increased the proportion of fast type IIB myosin heavy chain isoforms in T. anterior (up to 10% each, P  myostatin is absent and IGF1 is in excess. Finally, we show that myostatin and IGF1 regulate skeletal muscle size, myofibre type and gonadal fat through distinct mechanisms that involve increasing the total abundance and phosphorylation status of AKT and rpS6. © 2017 Society for Endocrinology.

  9. H2O2 attenuates IGF-1R tyrosine phosphorylation and its survival signaling properties in neuronal cells via NR2B containing NMDA receptor.

    Science.gov (United States)

    Zeng, Zhiwen; Wang, Dejun; Gaur, Uma; Rifang, Liao; Wang, Haitao; Zheng, Wenhua

    2017-09-12

    Impairment of insulin-like growth factor I (IGF-I) signaling plays an important role in the development of neurodegeneration. In the present study, we investigated the effect of H 2 O 2 on the survival signaling of IGF-1 and its underlying mechanisms in human neuronal cells SH-SY5Y. Our results showed that IGF-1 promoted cell survival and stimulated phosphorylation of IGF-1R as well as its downstream targets like AKT and ERK1/2 in these cells. Meanwhile, these effects of IGF-1 were abolished by H 2 O 2 at 200μM concentration which did not cause any significant toxicity to cells itself in our experiments. Moreover, studies using various glutamate receptor subtype antagonists displayed that N-methyl-D -aspartate (NMDA) receptor antagonist dizocilpine maleate (MK-801) blocked the effects of H 2 O 2 , whereas other glutamate receptor subtype antagonists, such as non-NMDA receptor antagonist 6,7-dinitroquinoxaline-2,3-dione (DNQX), metabolic glutamate receptor antagonists LY341495 and CPCCOEt, had no effect. Further studies revealed that NR2B-containing NMDARs are responsible for these effects as its effects were blocked by pharmacological inhibitor Ro25-698 or specific siRNA for NR2B, but not NR2A. Finally, our data also showed that Ca 2+ influx contributes to the effects of H 2 O 2 . Similar results were obtained in primary cultured cortical neurons. Taken together, the results from the present study suggested that H 2 O 2 attenuated IGF-1R tyrosine phosphorylation and its survival signaling properties via NR2B containing NMDA receptors and Ca 2+ influx in SH-SY5Y cells. Therefore, NMDAR antagonists, especially NR2B-selective ones, combined with IGF-1 may serve as an alternative therapeutic agent for oxidative stress related neurodegenerative disease.

  10. Insulin-like growth factor binding protein-3 induces angiogenesis through IGF-I- and SphK1-dependent mechanisms.

    Science.gov (United States)

    Granata, R; Trovato, L; Lupia, E; Sala, G; Settanni, F; Camussi, G; Ghidoni, R; Ghigo, E

    2007-04-01

    Angiogenesis is critical for development and repair, and is a prominent feature of many pathological conditions. Based on evidence that insulin-like growth factor binding protein (IGFBP)-3 enhances cell motility and activates sphingosine kinase (SphK) in human endothelial cells, we have investigated whether IGFBP-3 plays a role in promoting angiogenesis. IGFBP-3 potently induced network formation by human endothelial cells on Matrigel. Moreover, it up-regulated proangiogenic genes, such as vascular endothelial growth factor (VEGF) and matrix metalloproteinases (MMP)-2 and -9. IGFBP-3 even induced membrane-type 1 MMP (MT1-MMP), which regulates MMP-2 activation. Decreasing SphK1 expression by small interfering RNA (siRNA), blocked IGFBP-3-induced network formation and inhibited VEGF, MT1-MMP but not IGF-I up-regulation. IGF-I activated SphK, leading to sphingosine-1-phosphate (S1P) formation. The IGF-I effect on SphK activity was blocked by specific inhibitors of IGF-IR, PI3K/Akt and ERK1/2 phosphorylation. The disruption of IGF-I signaling prevented the IGFBP-3 effect on tube formation, SphK activity and VEGF release. Blocking ERK1/2 signaling caused the loss of SphK activation and VEGF and IGF-I up-regulation. Finally, IGFBP-3 dose-dependently stimulated neovessel formation into subcutaneous implants of Matrigel in vivo. Thus, IGFBP-3 positively regulates angiogenesis through involvement of IGF-IR signaling and subsequent SphK/S1P activation.

  11. Metformin-mediated growth inhibition involves suppression of the IGF-I receptor signalling pathway in human pancreatic cancer cells

    International Nuclear Information System (INIS)

    Karnevi, Emelie; Said, Katarzyna; Andersson, Roland; Rosendahl, Ann H

    2013-01-01

    Epidemiological studies have shown direct associations between type 2 diabetes and obesity, both conditions associated with hyperglycaemia and hyperinsulinemia, and the risk of pancreatic cancer. Up to 80% of pancreatic cancer patients present with either new-onset type 2 diabetes or impaired glucose tolerance at the time of diagnosis. Recent population studies indicate that the incidence of pancreatic cancer is reduced among diabetics taking metformin. In this study, the effects of exposure of pancreatic cancer cells to high glucose levels on their growth and response to metformin were investigated. The human pancreatic cancer cell lines AsPC-1, BxPC-3, PANC-1 and MIAPaCa-2 were grown in normal (5 mM) or high (25 mM) glucose conditions, with or without metformin. The influence by metformin on proliferation, apoptosis and the AMPK and IGF-IR signalling pathways were evaluated in vitro. Metformin significantly reduced the proliferation of pancreatic cancer cells under normal glucose conditions. Hyperglycaemia however, protected against the metformin-induced growth inhibition. The anti-proliferative actions of metformin were associated with an activation of AMP-activated protein kinase AMPK Thr172 together with an inhibition of the insulin/insulin-like growth factor-I (IGF-I) receptor activation and downstream signalling mediators IRS-1 and phosphorylated Akt. Furthermore, exposure to metformin during normal glucose conditions led to increased apoptosis as measured by poly(ADP-ribose) polymerase (PARP) cleavage. In contrast, exposure to high glucose levels promoted a more robust IGF-I response and Akt activation which correlated to stimulated AMPK Ser485 phosphorylation and impaired AMPK Thr172 phosphorylation, resulting in reduced anti-proliferative and apoptotic effects by metformin. Our results indicate that metformin has direct anti-tumour activities in pancreatic cancer cells involving AMPK Thr172 activation and suppression of the insulin/IGF signalling pathways

  12. IGF-I and GH: potential use in gene doping.

    Science.gov (United States)

    Harridge, Stephen D R; Velloso, Cristiana P

    2009-08-01

    Gene doping is the term given to the potential misuse of gene therapy for the purposes of enhancing athletic performance. Insulin like growth factor-I (IGF-I), the prime target of growth hormone action, is one candidate gene for improving performance. In recent years a number of transgenic and somatic gene transfer studies on animals have shown that upregulation of IGF-I stimulates muscle growth and improves function. This increase in muscle IGF-I is not reflected in measurable increases in circulating IGF-I. Whilst the responses obtained in the animal studies would appear to give clear benefits for performance, the transfer of such techniques to humans still presents many technical challenges. Further challenges will also be faced by the anti doping authorities in detecting the endogenously produced products of enhanced gene expression.

  13. Forkhead box A1 (FOXA1) is a key mediator of insulin-like growth factor I (IGF-I) activity.

    Science.gov (United States)

    Potter, Adam S; Casa, Angelo J; Lee, Adrian V

    2012-01-01

    The insulin-like growth factor receptor (IGF-IR) has been implicated in a number of human tumors, including breast cancer. Data from human breast tumors has demonstrated that IGF-IR is over-expressed and hyper-phosphorylated. Additionally, microarray analysis has shown that IGF-I treatment of MCF7 cells leads to a gene signature comprised of induced and repressed genes, which correlated with luminal B tumors. FOXA1, a forkhead family transcription factor, has been shown to be crucial for mammary ductal morphogenesis, similar to IGF-IR, and expressed at high levels in luminal subtype B breast tumors. Here, we investigated the relationship between FOXA1 and IGF-I action in breast cancer cells. We show that genes regulated by IGF-I are enriched for FOXA1 binding sites, and knock down of FOXA1 blocked the ability of IGF-I to regulate gene expression. IGF-I treatment of MCF7 cells increased the half-life of FOXA1 protein and this increase in half-life appeared to be dependent on canonical IGF-I signal transduction through both MAPK and AKT pathways. Finally, knock down of FOXA1 led to a decreased ability of IGF-I to induce proliferation and protect against apoptosis. Together, these results demonstrate that IGF-I can increase the stability of FOXA1 protein expression and place it as a critical mediator of IGF-I regulation of gene expression and IGF-I-mediated biological responses. Copyright © 2011 Wiley Periodicals, Inc.

  14. [Differences in dynamics of insulin and insulin-like growth I (IGF-I) receptors internalization in isolated rat hepatocytes].

    Science.gov (United States)

    Kolychev, A P; Ternovskaya, E E; Arsenieva, A V; Shapkina, E V

    2013-01-01

    Insulin and IGF-I are two related peptides performing in the mammalian body functionally different roles of the metabolic and growth hormones, respectively. Internalization of the insulin-receptor complex (IRC) is the most important chain of mechanism of the action of hormone. To elucidate differences in the main stages of internalization of the two related hormones, the internalization dynamics of 125I-insulin and 125I-IGF-I was traced in isolated rat hepatocytes at 37 and 12 degrees C. There were established marked differences in the process of internalization of labeled hormones, which is stimulated by insulin and IGF-I. At 37 degrees C the insulin-stimulated internalization, unlike the process initiated by IGF-I, did not reach the maximal level for 1 h of incubation. However, essential differences in the internalization course of these two related peptide were obvious at the temperature of 12 degrees C. The internalization level of insulin receptors at 12 degrees C decreased by one third in spite of a significant increase of the insulin receptor binding on the hepatocytes plasma membrane. At 12 degrees C a slight decrease of the proportion of intracellular 125I-IGF-I correlated with a decrease in the 125I-IGF-I binding to receptors on the cell membrane. Internalization of IGF-I receptors was not affected by low temperature, as neither its level, nor the rate changed at 12 degrees C. The paradoxical decrease of the insulin-stimulated internalization at low temperature seems to represent a peculiar "inhibition mechanism" of immersion of IRC into the cell, which leads to accumulation of the complexes on the cell surface and possibly to a readjustment of the insulin biological activity. The resistance of internalization of the IGF-I receptor to cold seems to be related to the more ancient origin of this mechanism in the poikilothermal vertebrates.

  15. Astragalus Extract Mixture HT042 Increases Longitudinal Bone Growth Rate by Upregulating Circulatory IGF-1 in Rats

    Directory of Open Access Journals (Sweden)

    Donghun Lee

    2017-01-01

    Full Text Available Astragalus extract mixture HT042 is a standardized ingredient of health functional food approved by Korean FDA with a claim of “height growth of children.” HT042 stimulates bone growth rate and increases local IGF-1 expression in growth plate of rats which can be considered as direct stimulation of GH and its paracrine/autocrine actions. However, it remains unclear whether HT042 stimulates circulatory IGF-1 which also plays a major role to stimulate bone growth. To determine the effects on circulatory IGF-1, IGF-1 and IGFBP-3 expressions and phosphorylation of JAK2/STAT5 were evaluated in the liver after 10 days of HT042 administration. HT042 upregulated liver IGF-1 and IGFBP-3 mRNA expression, IGF-1 protein expression, and phosphorylation of JAK2/STAT5. HT042 also increased bone growth rate and proliferative zonal height in growth plate. In conclusion, HT042 stimulates bone growth rate via increment of proliferative rate by upregulation of liver IGF-1 and IGFBP-3 mRNA followed by IGF-1 protein expression through phosphorylation of JAK2/STAT5, which can be regarded as normal functioning of GH-dependent endocrine pathway.

  16. Rosiglitazone Inhibits Adrenocortical Cancer Cell Proliferation by Interfering with the IGF-IR Intracellular Signaling

    Directory of Open Access Journals (Sweden)

    Luconi Michaela

    2008-07-01

    Full Text Available Rosiglitazone (RGZ, a thiazolidinedione ligand of the peroxisome proliferator-activated receptor (PPAR-γ, has been recently described as possessing antitumoral properties. We investigated RGZ effect on cell proliferation in two cell line models (SW13 and H295R of human adrenocortical carcinoma (ACC and its interaction with the signaling pathways of the activated IGF-I receptor (IGF-IR. We demonstrate a high expression of IGF-IR in the two cell lines and in ACC. Cell proliferation is stimulated by IGF-I in a dose- and time-dependent manner and is inhibited by RGZ. The analysis of the main intracellular signaling pathways downstream of the activated IGF-IR, phosphatidyl inositol 3-kinase (PI3K-Akt, and extracellular signal-regulated kinase (ERK1/2 cascades reveals that RGZ rapidly interferes with the Akt and ERK1/2 phosphorylation/activation which mediates IGF-I stimulated proliferation. In conclusion, our results suggest that RGZ exerts an inhibitory effect on human ACC cell proliferation by interfering with the PI3K/Akt and ERK1/2 signaling pathways downstream of the activated IGF-IR.

  17. IGF-I abuse in sport.

    Science.gov (United States)

    Guha, Nishan; Dashwood, Alexander; Thomas, Nicholas J; Skingle, Alexander J; Sönksen, Peter H; Holt, Richard I G

    2009-09-01

    It is widely believed that growth hormone (GH) is abused by athletes for its anabolic and lipolytic effects. Many of the physiological effects of GH are mediated by the production of insulin-like growth factor-I (IGF-I). Both GH and IGF-I appear on the World Anti-Doping Agency list of prohibited substances. Little is known, however, about the prevalence of abuse with exogenous IGF-I. IGF-I has effects on carbohydrate, lipid and protein metabolism and some of these actions could prove beneficial to competitive athletes. No studies have demonstrated a positive effect of IGF-I on physical performance in healthy individuals but this has not yet been studied in appropriately designed trials. Two pharmaceutical preparations of IGF-I have recently become available for the treatment of growth disorders in children. This availability is likely to increase the prevalence of IGF-I abuse. Combining IGF-I with its binding protein IGFBP-3 in one preparation has the potential to reduce the side-effect profile but the adverse effects of long term IGF-I abuse are currently unknown. Detection of abuse with IGF-I is a major challenge for anti-doping authorities. It is extremely difficult to distinguish the exogenous recombinant form of the hormone from endogenously-produced IGF-I. One approach currently being investigated is based on measuring markers of GH and IGF-I action. This has already proved successful in the fight against GH abuse and, it is hoped, will subsequently lead to a similar test for detection of IGF-I abuse.

  18. Prenatal stress affects insulin-like growth factor-1 (IGF-1) level and IGF-1 receptor phosphorylation in the brain of adult rats.

    Science.gov (United States)

    Basta-Kaim, Agnieszka; Szczesny, Ewa; Glombik, Katarzyna; Stachowicz, Katarzyna; Slusarczyk, Joanna; Nalepa, Irena; Zelek-Molik, Agnieszka; Rafa-Zablocka, Katarzyna; Budziszewska, Boguslawa; Kubera, Marta; Leskiewicz, Monika; Lason, Wladyslaw

    2014-09-01

    It has been shown that stressful events occurring in early life have a powerful influence on the development of the central nervous system. Insulin-like growth factor-1 (IGF-1) promotes the growth, differentiation and survival of both neurons and glial cells and is thought to exert antidepressant-like activity. Thus, it is possible that disturbances in the function of the IGF-1 system may be responsible for disturbances observed over the course of depression. Prenatal stress was used as a valid model of depression. Adult male offspring of control and stressed rat dams were subjected to behavioural testing (forced swim test). The level of IGF-1 in the blood and the expression of IGF-1, IGF-1R, and IRS-1/2 in the hippocampus and frontal cortex using RT-PCR, ELISA and western blotting were measured. In addition the effect of intracerebroventricularly administered IGF-1 and/or the IGF-1R receptor antagonist JB1 in the forced swim test was studied. Prenatally stressed rats showed depressive like behaviour, including increased immobility time as well as decreased mobility and climbing. Intracerebroventricular administration of IGF-1 reversed these effects in stressed animals, whereas concomitant administration of the IGF-1R antagonist JB1 completely blocked the effects. Biochemical analysis of homogenates from the hippocampus and frontal cortex revealed decreases in IGF-1 level and IGF-1R phosphorylation along with disturbances in IRS-1 phosphorylation. These findings reveal that prenatal stress alters IGF-1 signalling, which may contribute to the behavioural changes observed in depression. Copyright © 2014 Elsevier B.V. and ECNP. All rights reserved.

  19. Expression of IGF-I, IGF-I receptor and IGF binding proteins-1, -2, -3, -4 and -5 in human atherectomy specimens.

    Science.gov (United States)

    Grant, M B; Wargovich, T J; Ellis, E A; Tarnuzzer, R; Caballero, S; Estes, K; Rossing, M; Spoerri, P E; Pepine, C

    1996-12-17

    The molecular and cellular processes that induce rapid atherosclerotic plaque progression in patients with unstable angina and initiate restenosis following coronary interventional procedures are uncertain. We examined primary (de novo) and restenotic lesions retrieved at the time of directional coronary atherectomy for expression of insulin-like-growth factor-I (IGF-I). IGF-I receptor, and five IGF binding proteins (IGFBPs), IGFBP-1, IGFBP-2, IGFBP-3, IGFBP-4, and IGFBP-5 in smooth muscle cells (SMCs) using colloidal gold immunocytochemistry. IGF-1, its receptor and binding proteins were not detected in SMCs of normal coronary arteries. IGF-I localized primarily in synthetic smooth muscle cells (sSMCs) in both de novo and restenotic plaques. IGF-I receptor localized on sSMCs and their processes and colocalized with IGF-I. Although morphometric analysis of IGF-I and IGF-I receptor immunoreactivity in sSMCs of de novo and restenotic lesions showed comparable levels of IGF-I (3.2 +/- 1.0 and 2.9 +/- 0.9, respectively). IGF-I receptor was significantly higher in de novo lesions as compared to restenotic lesions (10.7 +/- 2.5 and 4.2 +/- 1.3, P system.

  20. IRS-1 acts as an endocytic regulator of IGF-I receptor to facilitate sustained IGF signaling.

    Science.gov (United States)

    Yoneyama, Yosuke; Lanzerstorfer, Peter; Niwa, Hideaki; Umehara, Takashi; Shibano, Takashi; Yokoyama, Shigeyuki; Chida, Kazuhiro; Weghuber, Julian; Hakuno, Fumihiko; Takahashi, Shin-Ichiro

    2018-04-11

    Insulin-like growth factor-I receptor (IGF-IR) preferentially regulates the long-term IGF activities including growth and metabolism. Kinetics of ligand-dependent IGF-IR endocytosis determines how IGF induces such downstream signaling outputs. Here, we find that the insulin receptor substrate (IRS)-1 modulates how long ligand-activated IGF-IR remains at the cell surface before undergoing endocytosis in mammalian cells. IRS-1 interacts with the clathrin adaptor complex AP2. IRS-1, but not an AP2-binding-deficient mutant, delays AP2-mediated IGF-IR endocytosis after the ligand stimulation. Mechanistically, IRS-1 inhibits the recruitment of IGF-IR into clathrin-coated structures; for this reason, IGF-IR avoids rapid endocytosis and prolongs its activity on the cell surface. Accelerating IGF-IR endocytosis via IRS-1 depletion induces the shift from sustained to transient Akt activation and augments FoxO-mediated transcription. Our study establishes a new role for IRS-1 as an endocytic regulator of IGF-IR that ensures sustained IGF bioactivity, independent of its classic role as an adaptor in IGF-IR signaling. © 2018, Yoneyama et al.

  1. Insulin and IGF-II, but not IGF-I, stimulate the in vitro regeneration of adult frog sciatic sensory axons

    DEFF Research Database (Denmark)

    Edbladh, M; Svenningsen, Åsa Fex; Ekström, P A

    1994-01-01

    We used the in vitro regenerating frog sciatic nerve to look for effects of insulin and insulin-like growth factors I and II (IGF-I, IGF-II) on regeneration of sensory axons and on injury induced support cell proliferation in the outgrowth region. In nerves cultured for 11 days, a physiological...

  2. Saw palmetto extract suppresses insulin-like growth factor-I signaling and induces stress-activated protein kinase/c-Jun N-terminal kinase phosphorylation in human prostate epithelial cells.

    Science.gov (United States)

    Wadsworth, Teri L; Carroll, Julie M; Mallinson, Rebecca A; Roberts, Charles T; Roselli, Charles E

    2004-07-01

    A common alternative therapy for benign prostatic hyperplasia (BPH) is the extract from the fruit of saw palmetto (SPE). BPH is caused by nonmalignant growth of epithelial and stromal elements of the prostate. IGF action is important for prostate growth and development, and changes in the IGF system have been documented in BPH tissues. The main signaling pathways activated by the binding of IGF-I to the IGF-I receptor (IGF-IR) are the ERK arm of the MAPK cascade and the phosphoinositol-3-kinase (PI3K)/protein kinase B (PKB/Akt) cascade. We tested the hypothesis that SPE suppresses growth and induces apoptosis in the P69 prostate epithelial cell line by inhibiting IGF-I signaling. Treatment with 150 microg/ml SPE for 24 h decreased IGF-I-induced proliferation of P69 cells and induced cleavage of the enzyme poly(ADP-ribose)polymerase (PARP), an index of apoptosis. Treatment of serum-starved P69 cells with 150 microg/ml SPE for 6 h reduced IGF-I-induced phosphorylation of Akt (assessed by Western blot) and Akt activity (assessed by an Akt kinase assay). Western blot analysis showed that SPE reduced IGF-I-induced phosphorylation of the adapter protein insulin receptor substrate-1 and decreased downstream effects of Akt activation, including increased cyclin D1 levels and phosphorylation of glycogen synthase kinase-3 and p70(s6k). There was no effect on IGF-I-induced phosphorylation of MAPK, IGF-IR, or Shc. Treatment of starved cells with SPE alone induced phosphorylation the proapoptotic protein JNK. SPE treatment may relieve symptoms of BPH, in part, by inhibiting specific components of the IGF-I signaling pathway and inducing JNK activation, thus mediating antiproliferative and proapoptotic effects on prostate epithelia.

  3. Comparison of Efficacy of Endogenous and Exogenous IGF-I in Stimulating Matrix Production in Neonatal and Mature Chondrocytes.

    Science.gov (United States)

    Aguilar, Izath N; Trippel, Stephen B; Shi, Shuiliang; Bonassar, Lawrence J

    2015-10-01

    The goal of this study was to compare the efficacy of endogenous upregulation of IGF-I by gene therapy and exogenous addition of insulin-like growth factor I (IGF-I) in enhancing proteoglycan synthesis by skeletally mature and neonatal chondrocytes. Chondrocyte transplantation therapy is a common treatment for focal cartilage lesions, with both mature and neonatal chondrocytes used as a cell source. Additionally, gene therapy strategies to upregulate growth factors such as IGF-I have been proposed to augment chondrocyte transplantation therapies. Both skeletally mature and neonatal chondrocytes were exposed to either an adeno-associated virus-based plasmid containing the IGF-I gene or exogenous IGF-I. Analysis of IGF-I and glycosaminoglycan production using a 4-parameter dose-response model established a clear connection between the amount of IGF-I produced by cells and their biosynthetic response. Both neonatal and mature chondrocytes showed this relationship, but the sensitivities were quite different, with EC50 of 0.57 ng/mL for neonatal chondrocytes and EC50 of 8.70 ng/mL IGF-I for skeletally mature chondrocytes. These data suggest that IGF-I gene therapy may be more effective with younger cell sources. Both cell types were less sensitive to exogenous IGF-I than endogenous IGF-I.

  4. The pro-Forms of Insulin-Like Growth Factor I (IGF-I) Are Predominant in Skeletal Muscle and Alter IGF-I Receptor Activation

    Science.gov (United States)

    Durzyńska, Julia; Philippou, Anastassios; Brisson, Becky K.; Nguyen-McCarty, Michelle

    2013-01-01

    IGF-I is a key regulator of muscle development and growth. The pre-pro-peptide produced by the Igf1gene undergoes several posttranslational processing steps to result in a secreted mature protein, which is thought to be the obligate ligand for the IGF-I receptor (IGF-IR). The goals of this study were to determine what forms of IGF-I exist in skeletal muscle, and whether the mature IGF-I protein was the only form able to activate the IGF-IR. We measured the proportion of IGF-I species in murine skeletal muscle and found that the predominant forms were nonglycosylated pro-IGF-I and glycosylated pro-IGF-I, which retained the C-terminal E peptide extension, instead of mature IGF-I. These forms were validated using samples subjected to viral expression of IGF-I combined with furin and glycosidase digestion. To determine whether the larger molecular weight IGF-I forms were also ligands for the IGF-IR, we generated each specific form through transient transfection of 3T3 cells and used the enriched media to perform kinase receptor activation assays. Compared with mature IGF-I, nonglycosylated pro-IGF-I had similar ability to activate the IGF-IR, whereas glycosylation of pro-IGF-I significantly reduced receptor activation. Thus, it is important to understand not only the quantity, but also the proportion of IGF-I forms produced, to evaluate the true biological activity of this growth factor. PMID:23407451

  5. Insulin and IGF-II, but not IGF-I, stimulate the in vitro regeneration of adult frog sciatic sensory axons

    DEFF Research Database (Denmark)

    Edbladh, M; Svenningsen, Åsa Fex; Ekström, P A

    1994-01-01

    We used the in vitro regenerating frog sciatic nerve to look for effects of insulin and insulin-like growth factors I and II (IGF-I, IGF-II) on regeneration of sensory axons and on injury induced support cell proliferation in the outgrowth region. In nerves cultured for 11 days, a physiological...... dose (10 ng/ml, approximately 2 nM) of insulin or IGF-II increased ganglionic protein synthesis (by 20% and 50%, respectively) as well as the level of newly formed, radiolabelled axonal material distal to a crush injury (both by 80%), compared to untreated, paired controls. In addition, insulin...... increased the outgrowth distance of the furthest regenerating sensory axons by 10%. The preparation was particularly sensitive to insulin during the first 5 days of culturing. Furthermore, both insulin and IGF-II were found to inhibit proliferation of support cells in the outgrowth region in a manner...

  6. Distinct signalling properties of insulin receptor substrate (IRS)-1 and IRS-2 in mediating insulin/IGF-1 action.

    Science.gov (United States)

    Rabiee, Atefeh; Krüger, Marcus; Ardenkjær-Larsen, Jacob; Kahn, C Ronald; Emanuelli, Brice

    2018-07-01

    Insulin/IGF-1 action is driven by a complex and highly integrated signalling network. Loss-of-function studies indicate that the major insulin/IGF-1 receptor substrate (IRS) proteins, IRS-1 and IRS-2, mediate different biological functions in vitro and in vivo, suggesting specific signalling properties despite their high degree of homology. To identify mechanisms contributing to the differential signalling properties of IRS-1 and IRS-2 in the mediation of insulin/IGF-1 action, we performed comprehensive mass spectrometry (MS)-based phosphoproteomic profiling of brown preadipocytes from wild type, IRS-1 -/- and IRS-2 -/- mice in the basal and IGF-1-stimulated states. We applied stable isotope labeling by amino acids in cell culture (SILAC) for the accurate quantitation of changes in protein phosphorylation. We found ~10% of the 6262 unique phosphorylation sites detected to be regulated by IGF-1. These regulated sites included previously reported substrates of the insulin/IGF-1 signalling pathway, as well as novel substrates including Nuclear Factor I X and Semaphorin-4B. In silico prediction suggests the protein kinase B (PKB), protein kinase C (PKC), and cyclin-dependent kinase (CDK) as the main mediators of these phosphorylation events. Importantly, we found preferential phosphorylation patterns depending on the presence of either IRS-1 or IRS-2, which was associated with specific sets of kinases involved in signal transduction downstream of these substrates such as PDHK1, MAPK3, and PKD1 for IRS-1, and PIN1 and PKC beta for IRS-2. Overall, by generating a comprehensive phosphoproteomic profile from brown preadipocyte cells in response to IGF-1 stimulation, we reveal both common and distinct insulin/IGF-1 signalling events mediated by specific IRS proteins. Copyright © 2018 Elsevier Inc. All rights reserved.

  7. Pancreatic Fibroblasts Stimulate the Motility of Pancreatic Cancer Cells through IGF1/IGF1R Signaling under Hypoxia.

    Directory of Open Access Journals (Sweden)

    Toshiki Hirakawa

    Full Text Available Pancreatic ductal adenocarcinoma (PDAC is characterized by its hypovascularity, with an extremely poor prognosis because of its highly invasive nature. PDAC proliferates with abundant stromal cells, suggesting that its invasive activity might be controlled by intercellular interactions between cancer cells and fibroblasts. Using four PDAC cell lines and two pancreas cancer-associated fibroblasts (CAFs, the expression of insulin-like growth factor-1 (IGF1 and IGF1 receptor (IGF1R was evaluated by RT-PCR, FACScan, western blot, or ELISA. Correlation between IGF1R and the hypoxia marker carbonic anhydrase 9 (CA9 was examined by immunohistochemical staining of 120 pancreatic specimens. The effects of CAFs, IGF1, and IGF1R inhibitors on the motility of cancer cells were examined by wound-healing assay or invasion assay under normoxia (20% O2 and hypoxia (1% O2. IGF1R expression was significantly higher in RWP-1, MiaPaCa-2, and OCUP-AT cells than in Panc-1 cells. Hypoxia increased the expression level of IGF1R in RWP-1, MiaPaCa-2, and OCUP-AT cells. CA9 expression was correlated with IGF1R expression in pancreatic specimens. CAFs produced IGF1 under hypoxia, but PDAC cells did not. A conditioned medium from CAFs, which expressed αSMA, stimulated the migration and invasion ability of MiaPaCa-2, RWP-1, and OCUP-AT cells. The motility of all PDAC cells was greater under hypoxia than under normoxia. The motility-stimulating ability of CAFs was decreased by IGF1R inhibitors. These findings might suggest that pancreas CAFs stimulate the invasion activity of PDAC cells through paracrine IGF1/IGF1R signaling, especially under hypoxia. Therefore the targeting of IGF1R signaling might represent a promising therapeutic approach in IGF1R-dependent PDAC.

  8. Pim-1 Kinase Phosphorylates Cardiac Troponin I and Regulates Cardiac Myofilament Function

    Directory of Open Access Journals (Sweden)

    Ni Zhu

    2018-03-01

    Full Text Available Background/Aims: Pim-1 is a serine/threonine kinase that is highly expressed in the heart, and exerts potent cardiac protective effects through enhancing survival, proliferation, and regeneration of cardiomyocytes. Its myocardial specific substrates, however, remain unknown. In the present study, we aim to investigate whether Pim-1 modulates myofilament activity through phosphorylation of cardiac troponin I (cTnI, a key component in regulating myofilament function in the heart. Methods: Coimmunoprecipitation and immunofluorescent assays were employed to investigate the interaction of Pim-1 with cTnI in cardiomyocytes. Biochemical, site directed mutagenesis, and mass spectrometric analyses were utilized to identify the phosphorylation sites of Pim1 in cTnI. Myofilament functional assay using skinned cardiac fiber was used to assess the effect of Pim1-mediated phosphorylation on cardiac myofilament activity. Lastly, the functional significance of Pim1-mediated cTnI in heart disease was determined in diabetic mice. Results: We found that Pim-1 specifically interacts with cTnI in cardiomyocytes and this interaction leads to Pim1-mediated cTnI phosphorylation, predominantly at Ser23/24 and Ser150. Furthermore, our functional assay demonstrated that Pim-1 induces a robust phosphorylation of cTnI within the troponin complex, thus leading to a decreased Ca2+ sensitivity. Insulin-like growth factor 1 (IGF-1, a peptide growth factor that has been shown to stimulate myocardial contractility, markedly induces cTnI phosphorylation at Ser23/24 and Ser150 through increasing Pim-1 expression in cardiomyocytes. In a high-fat diabetic mice model, the expression of Pim1 in the heart is significantly decreased, which is accompanied by a decreased phosphorylation of cTnI at Ser23/24 and Ser150, further implicating the pathological significance of the Pim1/cTnI axis in the development of diabetic cardiomyopathy. Conclusion: Our results demonstrate that Pim-1 is a

  9. Endocrine and Local IGF-I in the Bony Fish Immune System.

    Science.gov (United States)

    Franz, Anne-Constance; Faass, Oliver; Köllner, Bernd; Shved, Natallia; Link, Karl; Casanova, Ayako; Wenger, Michael; D'Cotta, Helena; Baroiller, Jean-François; Ullrich, Oliver; Reinecke, Manfred; Eppler, Elisabeth

    2016-01-26

    A role for GH and IGF-I in the modulation of the immune system has been under discussion for decades. Generally, GH is considered a stimulator of innate immune parameters in mammals and teleost fish. The stimulatory effects in humans as well as in bony fish often appear to be correlated with elevated endocrine IGF-I (liver-derived), which has also been shown to be suppressed during infection in some studies. Nevertheless, data are still fragmentary. Some studies point to an important role of GH and IGF-I particularly during immune organ development and constitution. Even less is known about the potential relevance of local (autocrine/paracrine) IGF-I within adult and developing immune organs, and the distinct localization of IGF-I in immune cells and tissues of mammals and fish has not been systematically defined. Thus far, IGF-I has been localized in different mammalian immune cell types, particularly macrophages and granulocytes, and in supporting cells, but not in T-lymphocytes. In the present study, we detected IGF-I in phagocytic cells isolated from rainbow trout head kidney and, in contrast to some findings in mammals, in T-cells of a channel catfish cell line. Thus, although numerous analogies among mammals and teleosts exist not only for the GH/IGF-system, but also for the immune system, there are differences that should be further investigated. For instance, it is unclear whether the primarily reported role of GH/IGF-I in the innate immune response is due to the lack of studies focusing on the adaptive immune system, or whether it truly preferentially concerns innate immune parameters. Infectious challenges in combination with GH/IGF-I manipulations are another important topic that has not been sufficiently addressed to date, particularly with respect to developmental and environmental influences on fish growth and health.

  10. Endocrine and Local IGF-I in the Bony Fish Immune System

    Directory of Open Access Journals (Sweden)

    Anne-Constance Franz

    2016-01-01

    Full Text Available A role for GH and IGF-I in the modulation of the immune system has been under discussion for decades. Generally, GH is considered a stimulator of innate immune parameters in mammals and teleost fish. The stimulatory effects in humans as well as in bony fish often appear to be correlated with elevated endocrine IGF-I (liver-derived, which has also been shown to be suppressed during infection in some studies. Nevertheless, data are still fragmentary. Some studies point to an important role of GH and IGF-I particularly during immune organ development and constitution. Even less is known about the potential relevance of local (autocrine/paracrine IGF-I within adult and developing immune organs, and the distinct localization of IGF-I in immune cells and tissues of mammals and fish has not been systematically defined. Thus far, IGF-I has been localized in different mammalian immune cell types, particularly macrophages and granulocytes, and in supporting cells, but not in T-lymphocytes. In the present study, we detected IGF-I in phagocytic cells isolated from rainbow trout head kidney and, in contrast to some findings in mammals, in T-cells of a channel catfish cell line. Thus, although numerous analogies among mammals and teleosts exist not only for the GH/IGF-system, but also for the immune system, there are differences that should be further investigated. For instance, it is unclear whether the primarily reported role of GH/IGF-I in the innate immune response is due to the lack of studies focusing on the adaptive immune system, or whether it truly preferentially concerns innate immune parameters. Infectious challenges in combination with GH/IGF-I manipulations are another important topic that has not been sufficiently addressed to date, particularly with respect to developmental and environmental influences on fish growth and health.

  11. c-myb stimulates cell growth by regulation of insulin-like growth factor (IGF) and IGF-binding protein-3 in K562 leukemia cells

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Min-Sun; Kim, Sun-Young; Arunachalam, Sankarganesh [Department of Pediatrics, School of Medicine, Chonbuk National University, Jeonju 561-712 (Korea, Republic of); Hwang, Pyoung-Han [Department of Pediatrics, School of Medicine, Chonbuk National University, Jeonju 561-712 (Korea, Republic of); Research Institute of Clinical Medicine, School of Medicine, Chonbuk National University, Jeonju 561-712 (Korea, Republic of); Yi, Ho-Keun [Department of Biochemistry, School of Dentistry, Chonbuk National University, Jeonju 561-712 (Korea, Republic of); Nam, Sang-Yun [Department of Alternative Therapy, School of Alternative Medicine and Health Science, Jeonju University, Jeonju 561-712 (Korea, Republic of); Lee, Dae-Yeol, E-mail: leedy@chonbuk.ac.kr [Department of Pediatrics, School of Medicine, Chonbuk National University, Jeonju 561-712 (Korea, Republic of); Research Institute of Clinical Medicine, School of Medicine, Chonbuk National University, Jeonju 561-712 (Korea, Republic of)

    2009-07-17

    c-myb plays an important role in the regulation of cell growth and differentiation, and is highly expressed in immature hematopoietic cells. The human chronic myelogenous leukemia cell K562, highly expresses IGF-I, IGF-II, IGF-IR, and IGF-induced cellular proliferation is mediated by IGF-IR. To characterize the impact of c-myb on the IGF-IGFBP-3 axis in leukemia cells, we overexpressed c-myb using an adenovirus gene transfer system in K562 cells. The overexpression of c-myb induced cell proliferation, compared to control, and c-myb induced cell growth was inhibited by anti-IGF-IR antibodies. c-myb overexpression resulted in a significant increase in the expression of IGF-I, IGF-II, and IGF-IR, and a decrease in IGFBP-3 expression. By contrast, disruption of c-myb function by DN-myb overexpression resulted in significant reduction of IGF-I, IGF-II, IGF-IR, and elevation of IGFBP-3 expression. In addition, exogenous IGFBP-3 inhibited the proliferation of K562 cells, and c-myb induced cell growth was blocked by IGFBP-3 overexpression in a dose-dependent manner. The growth-promoting effects of c-myb were mediated through two major intracellular signaling pathways, Akt and Erk. Activation of Akt and Erk by c-myb was completely blocked by IGF-IR and IGFBP-3 antibodies. These findings suggest that c-myb stimulates cell growth, in part, by regulating expression of the components of IGF-IGFBP axis in K562 cells. In addition, disruption of c-myb function by DN-myb may provide a useful strategy for treatment of leukemia.

  12. c-myb stimulates cell growth by regulation of insulin-like growth factor (IGF) and IGF-binding protein-3 in K562 leukemia cells

    International Nuclear Information System (INIS)

    Kim, Min-Sun; Kim, Sun-Young; Arunachalam, Sankarganesh; Hwang, Pyoung-Han; Yi, Ho-Keun; Nam, Sang-Yun; Lee, Dae-Yeol

    2009-01-01

    c-myb plays an important role in the regulation of cell growth and differentiation, and is highly expressed in immature hematopoietic cells. The human chronic myelogenous leukemia cell K562, highly expresses IGF-I, IGF-II, IGF-IR, and IGF-induced cellular proliferation is mediated by IGF-IR. To characterize the impact of c-myb on the IGF-IGFBP-3 axis in leukemia cells, we overexpressed c-myb using an adenovirus gene transfer system in K562 cells. The overexpression of c-myb induced cell proliferation, compared to control, and c-myb induced cell growth was inhibited by anti-IGF-IR antibodies. c-myb overexpression resulted in a significant increase in the expression of IGF-I, IGF-II, and IGF-IR, and a decrease in IGFBP-3 expression. By contrast, disruption of c-myb function by DN-myb overexpression resulted in significant reduction of IGF-I, IGF-II, IGF-IR, and elevation of IGFBP-3 expression. In addition, exogenous IGFBP-3 inhibited the proliferation of K562 cells, and c-myb induced cell growth was blocked by IGFBP-3 overexpression in a dose-dependent manner. The growth-promoting effects of c-myb were mediated through two major intracellular signaling pathways, Akt and Erk. Activation of Akt and Erk by c-myb was completely blocked by IGF-IR and IGFBP-3 antibodies. These findings suggest that c-myb stimulates cell growth, in part, by regulating expression of the components of IGF-IGFBP axis in K562 cells. In addition, disruption of c-myb function by DN-myb may provide a useful strategy for treatment of leukemia.

  13. Human IGF-I propeptide A promotes articular chondrocyte biosynthesis and employs glycosylation-dependent heparin binding.

    Science.gov (United States)

    Shi, Shuiliang; Kelly, Brian J; Wang, Congrong; Klingler, Ken; Chan, Albert; Eckert, George J; Trippel, Stephen B

    2018-03-01

    Insulin-like growth factor I (IGF-I) is a key regulator of chondrogenesis, but its therapeutic application to articular cartilage damage is limited by rapid elimination from the repair site. The human IGF-I gene gives rise to three IGF-I propeptides (proIGF-IA, proIGF-IB and proIGF-IC) that are cleaved to create mature IGF-I. In this study, we elucidate the processing of IGF-I precursors by articular chondrocytes, and test the hypotheses that proIGF-I isoforms bind to heparin and regulate articular chondrocyte biosynthesis. Human IGF-I propeptides and mutants were overexpressed in bovine articular chondrocytes. IGF-I products were characterized by ELISA, western blot and FPLC using a heparin column. The biosynthetic activity of IGF-I products on articular chondrocytes was assayed for DNA and glycosaminoglycan that the cells produced. Secreted IGF-I propeptides stimulated articular chondrocyte biosynthetic activity to the same degree as mature IGF-I. Of the three IGF-I propeptides, only one, proIGF-IA, strongly bound to heparin. Interestingly, heparin binding of proIGF-IA depended on N-glycosylation at Asn92 in the EA peptide. To our knowledge, this is the first demonstration that N-glycosylation determines the binding of a heparin-binding protein to heparin. The biosynthetic and heparin binding abilities of proIGF-IA, coupled with its generation of IGF-I, suggest that proIGF-IA may have therapeutic value for articular cartilage repair. These data identify human pro-insulin-like growth factor IA as a bifunctional protein. Its combined ability to bind heparin and augment chondrocyte biosynthesis makes it a promising therapeutic agent for cartilage damage due to trauma and osteoarthritis. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Early programming of the IGF-I axis

    DEFF Research Database (Denmark)

    Larnkjær, Anni; Ingstrup, Helga Kristensen; Schack-Nielsen, Lene

    2009-01-01

    -I production. Conversely, studies suggest that later in childhood, those breastfed are taller and have higher IGF-I levels. Therefore, it has been suggested that the IGF-I axis may be programmed by diet during infancy. The association between IGF-I in infancy and later life is not known. OBJECTIVE: To examine...... for gender, breastfeeding, and other covariates. Likelihood ratio test based on residual log likelihood was applied for analysis including all measurements during infancy. RESULTS: There was an inverse association between IGF-I at 9 months and 17 years (r=-0.39, P=0.014, and n=40). A 1 ng/ml higher IGF...... covariates except IGF-I at 2 months which was significantly negatively associated with IGF-I at 17 years (P=0.030) corresponding to a 0.96 ng/ml lower IGF-I concentration at 17 years per ng/ml IGF-I at 2 months. Inclusion of all measurements during infancy showed a negative association with 17-year values (r...

  15. Determination of LongR3-IGF-I, R3-IGF-I, Des1-3 IGF-I and their metabolites in human plasma samples by means of LC-MS.

    Science.gov (United States)

    Thomas, Andreas; Walpurgis, Katja; Delahaut, Philippe; Fichant, Eric; Schänzer, Wilhelm; Thevis, Mario

    2017-08-01

    According to the regulations of the World Anti-Doping Agency (WADA), growth promoting peptides such as the insulin-like growth factor-I (IGF-I) and its synthetic analogues belong to the class of prohibited compounds. While several assays to quantify endogenous IGF-I have been established, the potential misuse of synthetic analogues such as LongR 3 -IGF-I, R 3 -IGF-I and Des1-3-IGF-I remains a challenge and superior pharmacokinetic properties have been described for these analogues. Within the present study, it was demonstrated that the target peptides can be successfully detected in plasma samples by means of magnetic beads-based immunoaffinity purification and subsequent nanoscale liquid chromatographic separation with high resolution mass spectrometric detection. Noteworthy, the usage of a specific antibody for LongR 3 -IGF-I enables the determination in low ng/mL levels despite the presence of an enormous excess of endogenous human IGF-I. In addition, different metabolism studies (in-vitro and in-vivo) were performed using sophisticated strategies such as incubation with skin tissue microsomes, degradation in biological fluids (for all analogues), and administration to rats (for LongR 3 -IGF-I). Herewith, several C-and N-terminally truncated metabolites were identified and their relevancy was additionally confirmed by in-vivo experiments with rodents. Especially for LongR 3 -IGF-I, a metabolite ((Des1-11)-LongR 3 -IGF-I) was identified that prolonged the detectability in-vivo by a factor of approximately 2. The method was validated for qualitative interpretation considering the parameters specificity, identification capability, recovery (26-60%), limit of detection (0.5ng/mL), imprecision (IGF-I was used as internal standard to control all sample preparation steps. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. The Insulin-like Growth Factor (IGF)-I E-Peptides Modulate Cell Entry of the Mature IGF-I Protein

    OpenAIRE

    Pfeffer, Lindsay A.; Brisson, Becky K.; Lei, Hanqin; Barton, Elisabeth R.

    2009-01-01

    Insulin-like growth factor (IGF)-I is a critical protein for cell development and growth. Alternative splicing of the igf1 gene gives rise to multiple isoforms. In rodents, proIGF-IA and proIGF-IB have different carboxy-terminal extensions called the E-peptides (EA and EB) and upon further posttranslational processing, produce the identical mature IGF-I protein. Rodent EB has been reported to have mitogenic and motogenic effects independent of IGF-I. However, effects of EA or EB on mature IGF...

  17. Igf-I regulates pheochromocytoma cell proliferation and survival in vitro and in vivo.

    Science.gov (United States)

    Fernández, María Celia; Venara, Marcela; Nowicki, Susana; Chemes, Héctor E; Barontini, Marta; Pennisi, Patricia A

    2012-08-01

    IGFs are involved in malignant transformation and growth of several tissues, including the adrenal medulla. The present study was designed to evaluate the impact of IGF-I on pheochromocytoma development. We used a murine pheochromocytoma (MPC) cell line (MPC4/30) and an animal model with a reduction of 75% in circulating IGF-I levels [liver-IGF-I-deficient (LID) mice] to perform studies in vitro and in vivo. We found that, in culture, IGF-I stimulation increases proliferation, migration, and anchorage-independent growth, whereas it inhibits apoptosis of MPC cells. When injected to control and to LID mice, MPC cells grow and form tumors with features of pheochromocytoma. Six weeks after cell inoculation, all control mice developed sc tumors. In contrast, in 73% of LID mice, tumor development was delayed to 7-12 wk, and the remaining 27% did not develop tumors up to 12 wk after inoculation. LID mice harboring MPC cells and treated with recombinant human IGF-I (LID+) developed tumors as controls. Tumors developed in control, LID, and LID+ mice had similar histology and were similarly positive for IGF-I receptor expression. The apoptotic index was higher in tumors from LID mice compared with those from control mice, whereas vascular density was decreased. In summary, our work demonstrates that IGF-I has a critical role in maintaining tumor phenotype and survival of already transformed pheochromocytoma cells and is required for the initial establishment of these tumors, providing encouragement to carry on research studies to address the IGF-I/IGF-I receptor system as a target of therapeutic strategies for pheochromocytoma treatment in the future.

  18. High intakes of skimmed milk, but not meat, increase serum IGF-I and IGFBP-3 in eight-year-old boys

    DEFF Research Database (Denmark)

    Hoppe, C.; Mølgaard, C; Juul, A.

    2004-01-01

    To examine whether a high protein intake (PI) from either milk or meat, at a level often seen in late infancy, could increase s-IGF-I and s-IGF-I/s-IGFBP-3 in healthy, prepubertal children. IGF-I levels are positively associated with growth velocity in children and some studies suggest that a high...... animal PI can stimulate growth. During protein deprivation IGF-I decrease, but it is unknown whether a high PI can increase s-IGF-I in well-nourished children....

  19. IGF-I and branchial IGF receptor expression and localization during salinity acclimation in striped bass

    DEFF Research Database (Denmark)

    Tipsmark, Christian Kølbaek; Luckenbach, John Adam; Madsen, Steffen

    2007-01-01

    The initial response of the IGF-I system and the expression and cellular localization of IGF type-I receptor (IGF-IR) were studied in the gill of a euryhaline teleost during salinity acclimation. Exposure of striped bass (Morone saxatilis) to hyperosmotic and hypoosmotic challenges induced small...... in either plasma IGF-I, liver, or gill IGF-I mRNA, or gill IGF-IR mRNA levels. In a separate experiment, FW-acclimated fish were injected with saline or IGF-I prior to a 24-h SW challenge. Rapid regain of osmotic balance following SW transfer was hindered by IGF-I. Immunohistochemistry revealed...

  20. Phosphorylation of iRhom2 Controls Stimulated Proteolytic Shedding by the Metalloprotease ADAM17/TACE

    Directory of Open Access Journals (Sweden)

    Miguel Cavadas

    2017-10-01

    Full Text Available Cell surface metalloproteases coordinate signaling during development, tissue homeostasis, and disease. TACE (TNF-α-converting enzyme, is responsible for cleavage (“shedding” of membrane-tethered signaling molecules, including the cytokine TNF, and activating ligands of the EGFR. The trafficking of TACE within the secretory pathway requires its binding to iRhom2, which mediates the exit of TACE from the endoplasmic reticulum. An important, but mechanistically unclear, feature of TACE biology is its ability to be stimulated rapidly on the cell surface by numerous inflammatory and growth-promoting agents. Here, we report a role for iRhom2 in TACE stimulation on the cell surface. TACE shedding stimuli trigger MAP kinase-dependent phosphorylation of iRhom2 N-terminal cytoplasmic tail. This recruits 14-3-3 proteins, enforcing the dissociation of TACE from complexes with iRhom2, promoting the cleavage of TACE substrates. Our data reveal that iRhom2 controls multiple aspects of TACE biology, including stimulated shedding on the cell surface.

  1. Serum insulin-like growth factor-I (IGF-I) levels during long-term IGF-I treatment of children and adults with primary GH resistance (Laron syndrome).

    Science.gov (United States)

    Laron, Z; Klinger, B; Silbergeld, A

    1999-01-01

    Serum IGF-I levels were measured in 14 patients (9 children and 5 adults) with Laron syndrome (LS) during long-term treatment by IGF-I. Recombinant IGF-I (FK-780, Fujisawa Pharmaceutical Co. Ltd., Japan) was administered once daily subcutaneously before breakfast for 3-5 years to the children and for 9 months to the adults. The initial daily dose was 150 micrograms/kg for children and 120 micrograms/kg for adults. Before initiation of treatment the mean overnight fasting levels of serum IGF-I in the children was 3.2 +/- 0.8 nmol/l (mean +/- SEM), rising to 10 +/- 1.7 nmol/l during long-term treatment even on a dose of 120 micrograms/kg/day. The serum IGF-I levels 4 hours after injection rose from 31.2 +/- 3.5 to 48 +/- 2 nmol/l. In the adult patients, the initial basal IGF-I was 4.1 +/- 0.7 nmol/l, rising to 16.1 +/- 3.84 nmol/l after 8-9 months treatment. Serum IGF-I levels at 4 hours after injection rose in the adult patients from 24.1 +/- 5.8 up to 66.8 +/- 15.4 nmol/l. A progressively increasing half-life during long term exogenous administration of IGF-I to patients with Laron syndrome was demonstrated by following serum IGF-I dynamics after injection. Based on the fact that no antibodies to IGF-I were detected and on findings in previous studies, it is speculated that the increasing serum IGF-I levels during long-term IGF-I treatment are caused by an increase in serum IGFBP-3 induced by chronic IGF-I administration. It is concluded that treatment with IGF-I necessitates regular monitoring of serum IGF-I levels; in patients in whom the age adjusted maximal levels are exceeded, a reduction of the daily IGF-I dose is indicated to avoid undesirable effects.

  2. Interstitial fluid contains higher in vitro IGF bioactivity than serum

    DEFF Research Database (Denmark)

    Espelund, Ulrick; Søndergaard, Klaus; Bjerring, Peter

    2012-01-01

    MEASURE: Serum and SBF concentrations of bioactive IGF (determined in vitro by specific IGF-I receptor (IGF-IR) phosphorylation assay), immunoreactive IGF and IGF binding protein (IGFBP) levels, Western ligand blotting (WLB) of IGFBPs and IGFBP-3 Western immunoblotting (WiB). RESULTS: The ability of SBF...... to phosphorylate the IGF-IR in vitro was 41±27% higher than that of serum (P=0.007 by repeated measures ANOVA). By contrast, immunoreactive IGF and IGFBP-concentrations were approximately 50% lower in SBF than in serum (all P≤0.002). A marked difference in the composition of IGFBPs between serum and SBF...... was observed, including 3-fold elevated amounts of IGFBP-3 fragments in SBF (Pvitro IGF bioactivity was higher in SBF than in serum. This may...

  3. Do IGF-I concentrations better reflect growth hormone (GH action in children with short stature than the results of GH stimulating tests? Evidence from the simultaneous assessment of thyroid function

    Directory of Open Access Journals (Sweden)

    Smyczyńska Joanna

    2011-01-01

    Full Text Available Abstract Background The diagnosis of growth hormone (GH deficiency (GHD in short children seems unquestionable when both GH peak in stimulating tests (GHST and IGF-I concentration are decreased. However, the discrepancies between the results of GHST and IGF-I secretion are observed. It seems purposeful to determine the significance of GHST and IGF-I assessment in diagnosing GHD. The relationship between GH secretion and thyroid function, as well as GH influence on the peripheral thyroxine (T4 to triiodothyronine (T3 deiodination, mediated by IGF-I, were identified. Thus, clear differences in thyroid function between GH-deficient and non-GH-deficient subjects should exist. Methods Analysis comprised 800 children (541 boys, age 11.6 ± 3.1 years (mean ± SD, with short stature, in whom two (2 standard GHST (with clonidine and with glucagon were performed and IGF-I, free T4 (FT4, free T3 (FT3 and TSH serum concentrations were assessed. The patients were qualified to the following groups: GHD - decreased GH peak in GHST and IGF-I SDS (n = 81, ISS - normal GH peak and IGF-I SDS (n = 347, low GH - normal IGF-I SDS, and decreased GH peak (n = 212, low IGF - decreased IGF-I SDS, and normal GH peak (n = 160. The relationships among the results of particular tests were evaluated. Results In the groups with decreased IGF-I concentrations (GHD Group and low IGF Group, the more severe deficit of height was observed, together with higher TSH and FT4 but lower FT3 levels than in groups with normal IGF-I concentrations (ISS Group and low GH Group, independently of the results of GHST. TSH, FT4 and FT3 concentrations were - respectively - similar in two groups with decreased IGF-I secretion, as well as in two groups with normal IGF-I levels. Significant correlations were found between patients' height SDS and IGF-I SDS, between FT3 and IGF-I SDS (positive, and between FT4 and IGF-I SDS (negative, with no correlation between GH peak and any of the parameters

  4. Insulin Regulates Astrocytic Glucose Handling Through Cooperation With IGF-I.

    Science.gov (United States)

    Fernandez, Ana M; Hernandez-Garzón, Edwin; Perez-Domper, Paloma; Perez-Alvarez, Alberto; Mederos, Sara; Matsui, Takashi; Santi, Andrea; Trueba-Saiz, Angel; García-Guerra, Lucía; Pose-Utrilla, Julia; Fielitz, Jens; Olson, Eric N; Fernandez de la Rosa, Ruben; Garcia Garcia, Luis; Pozo, Miguel Angel; Iglesias, Teresa; Araque, Alfonso; Soya, Hideaki; Perea, Gertrudis; Martin, Eduardo D; Torres Aleman, Ignacio

    2017-01-01

    Brain activity requires a flux of glucose to active regions to sustain increased metabolic demands. Insulin, the main regulator of glucose handling in the body, has been traditionally considered not to intervene in this process. However, we now report that insulin modulates brain glucose metabolism by acting on astrocytes in concert with IGF-I. The cooperation of insulin and IGF-I is needed to recover neuronal activity after hypoglycemia. Analysis of underlying mechanisms show that the combined action of IGF-I and insulin synergistically stimulates a mitogen-activated protein kinase/protein kinase D pathway resulting in translocation of GLUT1 to the cell membrane through multiple protein-protein interactions involving the scaffolding protein GAIP-interacting protein C terminus and the GTPase RAC1. Our observations identify insulin-like peptides as physiological modulators of brain glucose handling, providing further support to consider the brain as a target organ in diabetes. © 2017 by the American Diabetes Association.

  5. IGF-1 prevents simvastatin-induced myotoxicity in C2C12 myotubes.

    Science.gov (United States)

    Bonifacio, Annalisa; Sanvee, Gerda M; Brecht, Karin; Kratschmar, Denise V; Odermatt, Alex; Bouitbir, Jamal; Krähenbühl, Stephan

    2017-05-01

    Statins are generally well tolerated, but treatment with these drugs may be associated with myopathy. The mechanisms of statin-associated myopathy are not completely understood. Statins inhibit AKT phosphorylation by an unclear mechanism, whereas insulin-like growth factor (IGF-1) activates the IGF-1/AKT signaling pathway and promotes muscle growth. The aims of the study were to investigate mechanisms of impaired AKT phosphorylation by simvastatin and to assess effects of IGF-1 on simvastatin-induced myotoxicity in C2C12 myotubes. C2C12 mouse myotubes were exposed to 10 μM simvastatin and/or 10 ng/mL IGF-1 for 18 h. Simvastatin inhibited the IGF-1/AKT signaling pathway, resulting in increased breakdown of myofibrillar proteins, impaired protein synthesis and increased apoptosis. Simvastatin inhibited AKT S473 phosphorylation, indicating reduced activity of mTORC2. In addition, simvastatin impaired stimulation of AKT T308 phosphorylation by IGF-1, indicating reduced activation of the IGF-1R/PI3K pathway by IGF-1. Nevertheless, simvastatin-induced myotoxicity could be at least partially prevented by IGF-1. The protective effects of IGF-1 were mediated by activation of the IGF-1R/AKT signaling cascade. Treatment with IGF-1 also suppressed muscle atrophy markers, restored protein synthesis and inhibited apoptosis. These results were confirmed by normalization of myotube morphology and protein content of C2C12 cells exposed to simvastatin and treated with IGF-1. In conclusion, impaired activity of AKT can be explained by reduced function of mTORC2 and of the IGF-1R/PI3K pathway. IGF-1 can prevent simvastatin-associated cytotoxicity and metabolic effects on C2C12 cells. The study gives insight into mechanisms of simvastatin-associated myotoxicity and provides potential targets for therapeutic intervention.

  6. IGF-1 protects cardiac myocytes from hyperosmotic stress-induced apoptosis via CREB

    International Nuclear Information System (INIS)

    Maldonado, Carola; Cea, Paola; Adasme, Tatiana; Collao, Andres; Diaz-Araya, Guillermo; Chiong, Mario; Lavandero, Sergio

    2005-01-01

    Hyperosmotic stress stimulates a rapid and pronounced apoptosis in cardiac myocytes which is attenuated by insulin-like growth factor-1 (IGF-1). Because in these cells IGF-1 induces intracellular Ca 2+ increase, we assessed whether the cyclic AMP response element-binding protein (CREB) is activated by IGF-1 through Ca 2+ -dependent signalling pathways. In cultured cardiac myocytes, IGF-1 induced phosphorylation (6.5 ± 1.0-fold at 5 min), nuclear translocation (30 min post-stimulus) and DNA binding activity of CREB. IGF-1-induced CREB phosphorylation was mediated by MEK1/ERK, PI3-K, p38-MAPK, as well as Ca 2+ /calmodulin kinase and calcineurin. Exposure of cardiac myocytes to hyperosmotic stress (sorbitol 600 mOsm) decreased IGF-1-induced CREB activation Moreover, overexpression of a dominant negative CREB abolished the anti-apoptotic effects of IGF-1. Our results suggest that IGF-1 activates CREB through a complex signalling pathway, and this transcription factor plays an important role in the anti-apoptotic action of IGF-1 in cultured cardiac myocytes

  7. Insulin-like growth factor (IGF-I and IGF binding proteins axis in diabetes mellitus

    Directory of Open Access Journals (Sweden)

    Min Sun Kim

    2015-06-01

    Full Text Available Increasing evidence suggests an important role of the insulin-like growth factor (IGF-IGF binding protein (IGFBP axis in the maintenance of normal glucose and lipid metabolism. Significant changes occur in the local IGF-I-IGFBPs environment in response to the diabetic milieu. A significant reduction of serum IGF-I levels was observed in patients with type 1 diabetes mellitus (T1DM. Inversely, considerably increased serum levels of IGF-I and IGFBP-3 levels were detected in individuals with glucose intolerance including T2DM. Recently, several prospective studies indicated that baseline levels of IGF-I and IGFBPs are associated with the development of diabetes. These findings suggest that disturbances in insulin and IGF-I-IGFBP axis can affect the development of glucose intolerance including diabetes.

  8. Differential binding of 125I-IGF-I preparations to human fibroblast monolayers

    International Nuclear Information System (INIS)

    Conover, C.A.; Misra, P.; Hintz, R.L.; Rosenfeld, R.G.

    1988-01-01

    Specific, high affinity binding of 125 I-IGF-I to the type IIGF receptor on human fibroblast monolyaers was not altered by varying feeding schedules, serum lots, washing procedures, or incubation times and temperatures. However, markedly different competitive binding curves were obtained when different iodinated IGF-I preparations were used. Five of six radioligands bound preferentially to the type IIGF receptor on human fibroblast monolayers, with 50% displacement at 4-8 μg/l unlabelled IGF-I; with one radioligand a paradoxical 20-200% increase in 125 I-IGF-I binding was observed at low concentrations of unlabelled IGF-I, while concentrations as high as 100 μg/l IGF-I failed to displace this radioligand. The latter binding pattern cannot be accounted for by 125 -I-IGF-I binding to the type II IGF receptor. These data indicate that various radioligands may have preferential affinities for different IGF-I binding sites on human fibroblast monolayers. (author)

  9. Insulin-like growth factor (IGF)-I obliterates the pregnancy-associated protection against mammary carcinogenesis in rats: evidence that IGF-I enhances cancer progression through estrogen receptor-α activation via the mitogen-activated protein kinase pathway

    International Nuclear Information System (INIS)

    Thordarson, Gudmundur; Slusher, Nicole; Leong, Harriet; Ochoa, Dafne; Rajkumar, Lakshmanaswamy; Guzman, Raphael; Nandi, Satyabrata; Talamantes, Frank

    2004-01-01

    Pregnancy protects against breast cancer development in humans and rats. Parous rats have persistently reduced circulating levels of growth hormone, which may affect the activity of the growth hormone/insulin-like growth factor (IGF)-I axis. We investigated the effects of IGF-I on parity-associated protection against mammary cancer. Three groups of rats were evaluated in the present study: IGF-I-treated parous rats; parous rats that did not receive IGF-I treatment; and age-matched virgin animals, which also did not receive IGF-I treatment. Approximately 60 days after N-methyl-N-nitrosourea injection, IGF-I treatment was discontinued and all of the animal groups were implanted with a silastic capsule containing 17β-estradiol and progesterone. The 17β-estradiol plus progesterone treatment continued for 135 days, after which the animals were killed. IGF-I treatment of parous rats increased mammary tumor incidence to 83%, as compared with 16% in parous rats treated with 17β-estradiol plus progesterone only. Tumor incidence and average number of tumors per animal did not differ between IGF-I-treated parous rats and age-matched virgin rats. At the time of N-methyl-N-nitrosourea exposure, DNA content was lowest but the α-lactalbumin concentration highest in the mammary glands of untreated parous rats in comparison with age-matched virgin and IGF-I-treated parous rats. The protein levels of estrogen receptor-α in the mammary gland was significantly higher in the age-matched virgin animals than in untreated parous and IGF-I-treated parous rats. Phosphorylation (activation) of the extracellular signal-regulated kinase-1/2 (ERK1/2) and expression of the progesterone receptor were both increased in IGF-I-treated parous rats, as compared with those in untreated parous and age-matched virgin rats. Expressions of cyclin D 1 and transforming growth factor-β 3 in the mammary gland were lower in the age-matched virgin rats than in the untreated parous and IGF-I-treated parous

  10. A polymorphism in the IGF-I gene influences the age-related decline in circulating total IGF-I levels

    NARCIS (Netherlands)

    I. Rietveld (Ingrid); J.A.M.J.L. Janssen (Joseph); A. Hofman (Albert); C.M. van Duijn (Cornelia); S.W.J. Lamberts (Steven); H.A.P. Pols (Huib)

    2003-01-01

    markdownabstractOBJECTIVE: Recent studies have demonstrated an association between a 192 bp polymorphism of the IGF-I gene and total IGF-I serum levels, birth weight, body height and the risk of developing diabetes and cardiovascular diseases later on in life. This IGF-I gene polymorphism in the

  11. Altered expression of IGF-I system in neurons of the inflamed spinal cord during acute experimental autoimmune encephalomyelitis.

    Science.gov (United States)

    Parvaneh Tafreshi, Azita; Talebi, Farideh; Ghorbani, Samira; Bernard, Claude; Noorbakhsh, Farshid

    2017-10-01

    There is growing evidence that the impaired IGF-I system contributes to neurodegeneration. In this study, we examined the spinal cords of the EAE, the animal model of multiple sclerosis, to see if the expression of the IGF-I system is altered. To induce EAE, C57/BL6 mice were immunized with the Hooke lab MOG kit, sacrificed at the peak of the disease and their spinal cords were examined for the immunoreactivities (ir) of the IGF-I, IGF binding protein-1 (IGFBP-1) and glycogen synthase kinase 3β (GSK3β), as one major downstream molecule in the IGF-I signaling. Although neurons in the non EAE spinal cords did not show the IGF-I immunoreactivity, they were numerously positive for the IGFBP-1. In the inflamed EAE spinal cord however, the patterns of expressions were reversed, that is, a significant increased number of IGF-I expressing neurons versus a reduced number of IGFBP-1 positive neurons. Moreover, while nearly all IGF-I-ir neurons expressed GSK3β, some expressed it more intensely. Considering our previous finding where we showed a significant reduced number of the inactive (phosphorylated) but not that of the total GSK3β expressing neurons in the EAE spinal cord, it is conceivable that the intense total GSK3β expression in the IGF-I-ir neurons belongs to the active form of GSK3β known to exert neuroinflammatory effects. We therefore suggest that the altered expression of the IGF-I system including GSK3β in spinal cord neurons might involve in pathophysiological events during the EAE. © 2017 Wiley Periodicals, Inc.

  12. Effects of dietary genistein on GH/IGF-I axis of Nile tilapia Oreochromis niloticus

    Science.gov (United States)

    Chen, Dong; Wang, Wei; Ru, Shaoguo

    2016-09-01

    There is considerable concern that isoflavones, such as genistein in fish feed composed of soybean protein, aff ects somatic growth in fish. Our previous works demonstrated that 30 and 300 μg/g dietary genistein had no significant eff ect on growth performance in Nile tilapia ( Oreochromis niloticus), but the higher level of genistein (3 000 μg/g) significantly depressed growth. This study was conducted to further examine the eff ects of dietary genistein on the endocrine disruption on growth hormone/insulin-like growth factor-I (GH/IGF-I) axis in Nile tilapia ( O. niloticus). Juvenile fish were fed by hand twice daily to satiation with one of four isonitrogenous and isoenergetic diets, each containing either 0, 30, 300 or 3 000 μg/g genistein. Following an 8-week feeding period, plasma GH and IGF-I levels were investigated by radioimmunoassay and gene expression levels of gh, ghrelin, gnrhs, ghr, npy, npyrs, pacap, ghrs, i gf-I, igf-Ir, and igfbp3 were examined by real-time PCR. The results show that no significant change in plasma GH and IGF-I levels in fish fed with diets containing 30 μg/g and 300 μg/g genistein. mRNA expression of genes along the GH/IGF-I axis remained unaff ected, except for igf-Ir, which was stimulated by the 300 μg/g genistein diet. While in fish fed the 3 000 μg/g genistein diet, the plasma GH and IGF-I levels decreased, and mRNA expression of gh, ghr2, npyr1, igf-I, and igf-Ir were also significantly depressed. In contrast, npy and igfbp3 mRNA expression were enhanced. This study provides convincing evidence for growth impediment by genistein by disturbing the GH/IGF-I axis in Nile tilapia O. niloticus.

  13. Significance of determination of female sex hormones (E2, LH, FSH), insulin-like growth factor I (IGF-I) and leptin in girls with precocious puberty

    International Nuclear Information System (INIS)

    Huang Jianrong

    2004-01-01

    Objective: To investigate the diagnostic value of determination of serum levels of estradiol (E 2 ), luteinizing hormone (LH) and follicle stimulating hormone (FSH), insulin-like growth factor (IGF-I) and leptin in girls with idiopathic central precocious puberty (ICPP). Methods: Serum E 2 , LH, FSH, IGF-I (with chemiluminescence immunoassay) and leptin (with RIA) levels were determined in 35 girls with early development of breast as the sign of precocious puberty, of which, 15 was considered to be of the ICPP group and 20 of simple premature thelarche group (SPT). Criteria of diagnosis for ICPP were: peak LH value>12IU/L and LH/FSH>1 after GnRH stimulating test. Results: Serum E 2 , LH, FSH, IGF-I leptin levels in girls with ICPP were significantly higher than those in the girls with SPT (P 0.2 as the cut-off value for diagnosis of ICPP there would still be a positive rate of 86.6% suggesting that the diagnostic criteria might be set lower. Serum IGF-I levels were positively correlated to those of E 2 (r=0.47, P 2 and IGF-I. Conclusion: Determinations of serum E 2 , LH, FHS, IGF-I and leptin levels were helpful for the early diagnosis of ICPP. (author)

  14. Human conditions of insulin-like growth factor-I (IGF-I) deficiency

    Science.gov (United States)

    2012-01-01

    Insulin-like growth factor I (IGF-I) is a polypeptide hormone produced mainly by the liver in response to the endocrine GH stimulus, but it is also secreted by multiple tissues for autocrine/paracrine purposes. IGF-I is partly responsible for systemic GH activities although it possesses a wide number of own properties (anabolic, antioxidant, anti-inflammatory and cytoprotective actions). IGF-I is a closely regulated hormone. Consequently, its logical therapeutical applications seems to be limited to restore physiological circulating levels in order to recover the clinical consequences of IGF-I deficiency, conditions where, despite continuous discrepancies, IGF-I treatment has never been related to oncogenesis. Currently the best characterized conditions of IGF-I deficiency are Laron Syndrome, in children; liver cirrhosis, in adults; aging including age-related-cardiovascular and neurological diseases; and more recently, intrauterine growth restriction. The aim of this review is to summarize the increasing list of roles of IGF-I, both in physiological and pathological conditions, underlying that its potential therapeutical options seem to be limited to those proven states of local or systemic IGF-I deficiency as a replacement treatment, rather than increasing its level upper the normal range. PMID:23148873

  15. Human conditions of insulin-like growth factor-I (IGF-I deficiency

    Directory of Open Access Journals (Sweden)

    Puche Juan E

    2012-11-01

    Full Text Available Abstract Insulin-like growth factor I (IGF-I is a polypeptide hormone produced mainly by the liver in response to the endocrine GH stimulus, but it is also secreted by multiple tissues for autocrine/paracrine purposes. IGF-I is partly responsible for systemic GH activities although it possesses a wide number of own properties (anabolic, antioxidant, anti-inflammatory and cytoprotective actions. IGF-I is a closely regulated hormone. Consequently, its logical therapeutical applications seems to be limited to restore physiological circulating levels in order to recover the clinical consequences of IGF-I deficiency, conditions where, despite continuous discrepancies, IGF-I treatment has never been related to oncogenesis. Currently the best characterized conditions of IGF-I deficiency are Laron Syndrome, in children; liver cirrhosis, in adults; aging including age-related-cardiovascular and neurological diseases; and more recently, intrauterine growth restriction. The aim of this review is to summarize the increasing list of roles of IGF-I, both in physiological and pathological conditions, underlying that its potential therapeutical options seem to be limited to those proven states of local or systemic IGF-I deficiency as a replacement treatment, rather than increasing its level upper the normal range.

  16. Normal Values of Circulating IGF-I Bioactivity in the Healthy Population: Comparison with five widely used IGF-I immunoassays

    NARCIS (Netherlands)

    M.P. Brugts (Michael); M.B. Ranke (Michael); L.J. Hofland (Leo); K. van der Wansem (Katy); K. Weber (Karin); J. Frystyk (Jan); S.W.J. Lamberts (Steven); J.A.M.J.L. Janssen (Joseph)

    2008-01-01

    textabstractBackground: IGF-I immunoassays are primarily used to estimate IGF-I bioactivity. Recently, an IGFI specific Kinase Receptor Activation Assay (KIRA) has been developed as an alternative method. However, no normative values have been established for the IGF-I KIRA. Objective: To

  17. Bone Growth Mechanical Stimulus and IGF-I

    National Research Council Canada - National Science Library

    Gilsanz, Vicente

    2003-01-01

    .... This study also examines the possible relations between the cross-sectional properties of bone and circulating levels of IGF-I, IGF-binding protein-3, and IGF-I genotypes in teenagers ages 15 to 20...

  18. Disposition of radiolabelled insulin-like growth factor I (IGF-I), IGF-II and their N-terminal truncated variants in rats

    International Nuclear Information System (INIS)

    Yamamoto, Hiroyuki; Kato, Yuzuru; Murphy, L.J.

    1996-01-01

    Serum half life, tissue uptake and urinary excretion of N-terminal truncated IGF variants and their intact precursors were compared to see whether the variants regulate the bioavailability of those growth factors. IGF-I, des(1-3) IGF-I, IGF-II and des(1-6) IGF-II were labeled with 125 I and intravenously administered to SD rats. Blood from femoral artery and urine from implanted bladder catheter were collected at appropriate intervals until sacrifice of animals at 2 hr after administration. Tissues were dissected out and all of these samples were measured for their radioactivity with a gamma counter. The half lives of des(1-3) IGF-I, IGF-I, des(1-6) IGF-II and IGF-II were 20.5, 228.3, 21.3 and 181.7 min, respectively. Maximal accumulation of all peptides was found in the kidney. 125 I-IGF-I and -II showed the following distribution pattern; levels were higher in the kidney>pancreas>small intestine>liver>duodenum>stomach>lung>spleen>heart>large intestine>testis>brain>skeletal muscle. Skeletal muscle, kidney and testis showed a preferential uptake of the variants. Urinary excretion of the variants were much greater. Thus the variants were more rapidly cleared from circulation. The physiological significance of tissue distribution of 4 peptides remains to be further investigated. (K.H.)

  19. Local administration of insulin-like growth factor-I (IGF-I) stimulates tendon collagen synthesis in humans

    DEFF Research Database (Denmark)

    Hansen, Mette; Boesen, Anders; Holm, Lars

    2013-01-01

    Collagen is the predominant structural protein in tendons and ligaments, and can be controlled by hormonal changes. In animals, injections of insulin-like growth factor I (IGF-I) has been shown to increase collagen synthesis in tendons and ligaments and to improve structural tissue healing, but t...

  20. Coordinated increase in skeletal muscle fiber area and expression of IGF-I with resistance exercise in elderly post-operative patients

    DEFF Research Database (Denmark)

    Suetta, Charlotte; Clemmensen, Christoffer; Andersen, Jesper L

    2010-01-01

    Hypertrophy of developing skeletal muscle involves stimulation by insulin-like growth factor-I (IGF-I), however, the role of IGF-I in adult muscle is less clarified. In the present study, the mRNA splice variants of IGF-I (IGF-IEa and MGF) and the changes in muscle fiber cross sectional area after...... and in addition induces marked increases in the expression of IGF-I splice variants, supporting the idea that IGF-I is involved in regulating muscle hypertrophy.......-operated-side served as a within subject control. Muscle biopsies were obtained from the vastus lateralis of both limbs at +2d post-operative (baseline), at 5weeks and 12weeks post-surgery to analyze for changes in type 1 and type 2 muscle fiber area. Changes in expression levels of IGF-I mRNA isoforms were determined...

  1. Insulin-like growth factors (IGFs) as autocrine/paracrine regulators of granulosa cell differentiation and growth: Studies with a neutralizing monoclonal antibody to IGF-I

    International Nuclear Information System (INIS)

    Mondschein, J.S.; Canning, S.F.; Miller, D.Q.; Hammond, J.M.

    1989-01-01

    Evidence that granulosa cells secrete and respond to insulin-like growth factors (IGFs) suggests, but does not prove, the importance of IGFs as intraovarian regulators. To further assess the role of these peptides in ovarian function, a neutralizing monoclonal antibody to IGF-I was employed to block the actions of IGFs in porcine follicular fluid and in granulosa cell-conditioned medium. In one series of experiments, granulosa cells from immature porcine follicles were cultured in medium containing porcine follicular fluid that had been charcoal-treated to remove steroids. As noted before, fluid from large follicles (LFF) stimulated progesterone production in a dose-dependent manner. The stimulatory effect of LFF (30% v/v) could be inhibited by greater than 50% by the anti-IGF monoclonal antibody. This inhibitory action was specific for the anti-IGF antibody and could be overcome by the addition of excess exogenous IGFs. In another series of experiments, granulosa cells were made dependent on endogenously produced IGFs by culturing them in a serum-free medium without exogenous growth factors. The effects of follicle-stimulating hormone (FSH), estradiol (E2), growth hormone (GH), and combinations thereof on progesterone production were inhibited by approximately 50% by the anti-IGF antibody. The effects of IGFs on indices of cell growth (judged by the criterion of being inhibited by the anti-IGF antibody) were less dramatic. A modest 18% increase in cell number was observed with FSH and E2 treatment in serum-free medium; this effect was virtually abolished by the antibody

  2. Insulin-like growth factors (IGFs) as autocrine/paracrine regulators of granulosa cell differentiation and growth: Studies with a neutralizing monoclonal antibody to IGF-I

    Energy Technology Data Exchange (ETDEWEB)

    Mondschein, J.S.; Canning, S.F.; Miller, D.Q.; Hammond, J.M. (Pennsylvania State Univ., Hershey (USA))

    1989-07-01

    Evidence that granulosa cells secrete and respond to insulin-like growth factors (IGFs) suggests, but does not prove, the importance of IGFs as intraovarian regulators. To further assess the role of these peptides in ovarian function, a neutralizing monoclonal antibody to IGF-I was employed to block the actions of IGFs in porcine follicular fluid and in granulosa cell-conditioned medium. In one series of experiments, granulosa cells from immature porcine follicles were cultured in medium containing porcine follicular fluid that had been charcoal-treated to remove steroids. As noted before, fluid from large follicles (LFF) stimulated progesterone production in a dose-dependent manner. The stimulatory effect of LFF (30% v/v) could be inhibited by greater than 50% by the anti-IGF monoclonal antibody. This inhibitory action was specific for the anti-IGF antibody and could be overcome by the addition of excess exogenous IGFs. In another series of experiments, granulosa cells were made dependent on endogenously produced IGFs by culturing them in a serum-free medium without exogenous growth factors. The effects of follicle-stimulating hormone (FSH), estradiol (E2), growth hormone (GH), and combinations thereof on progesterone production were inhibited by approximately 50% by the anti-IGF antibody. The effects of IGFs on indices of cell growth (judged by the criterion of being inhibited by the anti-IGF antibody) were less dramatic. A modest 18% increase in cell number was observed with FSH and E2 treatment in serum-free medium; this effect was virtually abolished by the antibody.

  3. Comparison of acid ethanol extraction and acid gel filtration prior to IGF-I and IGF-II radioimmunoassays

    International Nuclear Information System (INIS)

    Bang, P.; Eriksson, U.; Wivall, I.-L.; Hall, K.; Sara, V.

    1991-01-01

    Insulin-like growth factor binding proteins interfere in the IGF-I and -II radioimmunoassays. In an attempt to overcome this problem, we have compared the use of truncated IGF-I, with reduced IGFBP affinity, and IGF-I as radioligands for IGF-I RIA measurements in serum separated by acid gel filtration or acid ethanol extraction followed by cryo-precipitation. With truncated IGF-I as radioligand the IGF-I measurements in acid gel filtrates and acid ethanol extracts were significantly correlated in healthy subjects (N=42, r=0.91, p<0.001) and in patients with acromegaly (N=10, r=0.85, p<0.01), GH deficiency (N=10, r=0.88, p<0.001) or Type I diabetes mellitus (N=10, r=0.90, p<0.001). In contrast, the IGF-I concentrations in acid ethanol extracts determined with IGF-I as radioligand did not correlate with those in acid gel filtrates using truncated IGF-I radioligand in patients with acromegaly (r=0.61, NS) or GH deficiency (r=0.46, NS). In the latter group the mean IGF-I concentrations measured in acid ethanol extracts were erroneously elevated by 112%. Low-affinity antibodies used for IGF-II RIA determinations failed to give reliable results in acid ethanol extracts from patients with Type I diabetes mellitus or GH deficiency. In conclusion, erroneously high IGF-I concentrations owing to binding of the radioligand to IGFBPs not completely removed by acid ethanol extraction can be avoided by the use of truncated IGF-I as radioligand. (author)

  4. Organ-Specific and Age-Dependent Expression of Insulin-like Growth Factor-I (IGF-I) mRNA Variants: IGF-IA and IB mRNAs in the Mouse

    OpenAIRE

    Ohtsuki, Takashi; Otsuki, Mariko; Murakami, Yousuke; Maekawa, Tetsuya; Yamamoto, Takashi; Akasaka, Koji; Takeuchi, Sakae; Takahashi, Sumio

    2005-01-01

    Insulin-like growth factor-I (IGF-I) gene generates several IGF-I mRNA variants by alternative splicing. Two promoters are present in mouse IGF-I gene. Each promoter encodes two IGF-I mRNA variants (IGF-IA and IGF-IB mRNAs). Variants differ by the presence (IGF-IB) or absence (IGF-IA) of a 52-bp insert in the E domain-coding region. Functional differences among IGF-I mRNAs, and regulatory mechanisms for alternative splicing of IGF-I mRNA are not yet known. We analyzed the expression of mouse ...

  5. IGF-1-dependent subunit communication of the IGF-1 holoreceptor: Interactions between αβ heterodimeric receptor halves

    International Nuclear Information System (INIS)

    Wilden, P.A.; Treadway, J.L.; Morrison, B.D.; Pessin, J.E.

    1989-01-01

    Examination of 125 I-IGF-1 affinity cross-linking and β-subunit autophosphorylation has indicated that IGF-1 induces a covalent association of isolated αβ heterodimeric IGF-1 receptors into an α 2 β 2 heterotetrameric state, in a similar manner to that observed for the insulin receptor. The formation of the α 2 β 2 heterotetrameric IGF-1 receptor complex from the partially purified αβ heterodimers was time dependent with half-maximal formation in approximately 30 min at saturating IGF-1 concentrations. The IGF-1-dependent association of the partially purified αβ heterodimers into an α 2 β 2 heterotetrameric state was specific for the IGF-1 receptors since IGF-1 was unable to stimulate the protein kinase activity of the purified αβ heterodimeric insulin receptor complex. Incubation of the α 2 β 2 heterotetrameric IGF-1 holoreceptor with the specific sulfhydryl agent iodoacetamide (IAN) did not alter 125 I-IGF-1 binding or IGF-1 stimulation of protein kinase activity. However, IAN treatment of the αβ heterodimeric IGF-1 receptors inhibited the IGF-1 dependent covalent formation of the disulfide-linked α 2 β 2 heterotetrameric complex. These data indicate that IGF-1 induces the covalent association of isolated αβ heterodimeric IGF-1 receptor complexes into a disulfide-linked α 2 β 2 heterotetrameric state whereas Mn/MgATP induces a noncovalent association. Therefore, unlike the insulin receptor in which noncovalent association is sufficient for kinase activation, only the covalent assembly of the IGF-1 receptor αβ heterodimers into the α 2 β 2 heterotetrameric holoreceptor complex is associated with ligand-stimulated protein kinase activation

  6. Factor de crecimiento semejante a la insulina tipo I (IGF-I y cirrosis hepática Insulin-like growth factor I (IGF-I and liver cirrhosis

    Directory of Open Access Journals (Sweden)

    M. Conchillo

    2007-03-01

    Full Text Available El factor de crecimiento semejante a la insulina tipo I (IGF-I es una hormona polipeptídica segregada en múltiples tejidos por efecto de la hormona de crecimiento (GH. Es responsable de parte de las acciones de la GH y además tiene efecto hipoglucemiante y anabolizante. El 90% del IGF-I circulante es de origen hepático y ejerce efectos autocrinos, paracrinos y endocrinos, estos últimos en múltiples tejidos. En la cirrosis hepática se produce una disminución progresiva de la producción hepática de IGF-I que llega a ser indetectable en la enfermedad avanzada. Algunas de las complicaciones de la cirrosis, fundamentalmente nutricionales y metabólicas (resistencia a insulina, desnutrición, osteopenia, hipogonadismo, alteraciones intestinales podrían estar, al menos en parte, relacionadas con esta carencia de IGF-I dado que algunas acciones de IGF-I representan la imagen inversa de las complicaciones de la cirrosis. A pesar de ello, nunca se había propuesto tratamiento sustitutivo con IGF-I en la cirrosis. En una serie de estudios experimentales realizados en ratas cirróticas se demostró que el tratamiento con dosis bajas de IGF-I recombinante produce dos tipos de efectos en la cirrosis experimental: a mejoría del hígado, dado que mejora la función hepatocelular, la hipertensión portal y la fibrosis hepática; y b mejoría de las alteraciones extrahepáticas de la cirrosis dado que mejora la eficiencia del alimento ingerido, la masa muscular, la masa ósea, la función y estructura gonadales y la función y estructura intestinales con normalización de la malabsorción de azúcares y aminoácidos y la mejoría de la función intestinal de barrera manifestada por disminución de la endotoxemia y la translocación bacteriana. Posteriormente el primer ensayo clínico piloto, aleatorizado, doble ciego y controlado con placebo llevado a cabo en un número reducido de pacientes cirróticos demostró aumento de la albúmina sérica y

  7. Comparison of acid ethanol extraction and acid gel filtration prior to IGF-I and IGF-II radioimmunoassays; Improvement of determinations in acid ethanol extracts by the use of truncated IGF-I as radioligand

    Energy Technology Data Exchange (ETDEWEB)

    Bang, P; Eriksson, U; Wivall, I -L; Hall, K [Department of Endocrinology, Karolinska Institute, Stockholm (Sweden); Sara, V [Department of Pathology, Karolinska Institute, Stockholm (Sweden)

    1991-01-01

    Insulin-like growth factor binding proteins interfere in the IGF-I and -II radioimmunoassays. In an attempt to overcome this problem, we have compared the use of truncated IGF-I, with reduced IGFBP affinity, and IGF-I as radioligands for IGF-I RIA measurements in serum separated by acid gel filtration or acid ethanol extraction followed by cryo-precipitation. With truncated IGF-I as radioligand the IGF-I measurements in acid gel filtrates and acid ethanol extracts were significantly correlated in healthy subjects (N=42, r=0.91, p<0.001) and in patients with acromegaly (N=10, r=0.85, p<0.01), GH deficiency (N=10, r=0.88, p<0.001) or Type I diabetes mellitus (N=10, r=0.90, p<0.001). In contrast, the IGF-I concentrations in acid ethanol extracts determined with IGF-I as radioligand did not correlate with those in acid gel filtrates using truncated IGF-I radioligand in patients with acromegaly (r=0.61, NS) or GH deficiency (r=0.46, NS). In the latter group the mean IGF-I concentrations measured in acid ethanol extracts were erroneously elevated by 112%. Low-affinity antibodies used for IGF-II RIA determinations failed to give reliable results in acid ethanol extracts from patients with Type I diabetes mellitus or GH deficiency. In conclusion, erroneously high IGF-I concentrations owing to binding of the radioligand to IGFBPs not completely removed by acid ethanol extraction can be avoided by the use of truncated IGF-I as radioligand. (author).

  8. Enhanced contractile force generation by artificial skeletal muscle tissues using IGF-I gene-engineered myoblast cells.

    Science.gov (United States)

    Sato, Masanori; Ito, Akira; Kawabe, Yoshinori; Nagamori, Eiji; Kamihira, Masamichi

    2011-09-01

    The aim of this study was to investigate whether insulin-like growth factor (IGF)-I gene delivery to myoblast cells promotes the contractile force generated by hydrogel-based tissue-engineered skeletal muscles in vitro. Two retroviral vectors allowing doxycycline (Dox)-inducible expression of the IGF-I gene were transduced into mouse myoblast C2C12 cells to evaluate the effects of IGF-I gene expression on these cells. IGF-I gene expression stimulated the proliferation of C2C12 cells, and a significant increase in the growth rate was observed for IGF-I-transduced C2C12 cells with Dox addition, designated C2C12/IGF (Dox+) cells. Quantitative morphometric analyses showed that the myotubes induced from C2C12/IGF (Dox+) cells had a larger area and a greater width than control myotubes induced from normal C2C12 cells. Artificial skeletal muscle tissues were prepared from the respective cells using hydrogels composed of type I collagen and Matrigel. Western blot analyses revealed that the C2C12/IGF (Dox+) tissue constructs showed activation of a skeletal muscle hypertrophy marker (Akt) and enhanced expression of muscle-specific markers (myogenin, myosin heavy chain and tropomyosin). Moreover, the creatine kinase activity was increased in the C2C12/IGF (Dox+) tissue constructs. The C2C12/IGF (Dox+) tissue constructs contracted in response to electrical pulses, and generated a significantly higher physical force than the control C2C12 tissue constructs. These findings indicate that IGF-I gene transfer has the potential to yield functional skeletal muscle substitutes that are capable of in vivo restoration of the load-bearing function of injured muscle or acting as in vitro electrically-controlled bio-actuators. Copyright © 2011 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  9. Insulin-Like Growth Factor (IGF Binding Protein-2, Independently of IGF-1, Induces GLUT-4 Translocation and Glucose Uptake in 3T3-L1 Adipocytes

    Directory of Open Access Journals (Sweden)

    Biruhalem Assefa

    2017-01-01

    Full Text Available Insulin-like growth factor binding protein-2 (IGFBP-2 is the predominant IGF binding protein produced during adipogenesis and is known to increase the insulin-stimulated glucose uptake (GU in myotubes. We investigated the IGFBP-2-induced changes in basal and insulin-stimulated GU in adipocytes and the underlying mechanisms. We further determined the role of insulin and IGF-1 receptors in mediating the IGFBP-2 and the impact of IGFBP-2 on the IGF-1-induced GU. Fully differentiated 3T3-L1 adipocytes were treated with IGFBP-2 in the presence and absence of insulin and IGF-1. Insulin, IGF-1, and IGFBP-2 induced a dose-dependent increase in GU. IGFBP-2 increased the insulin-induced GU after long-term incubation. The IGFBP-2-induced impact on GU was neither affected by insulin or IGF-1 receptor blockage nor by insulin receptor knockdown. IGFBP-2 significantly increased the phosphorylation of PI3K, Akt, AMPK, TBC1D1, and PKCζ/λ and induced GLUT-4 translocation. Moreover, inhibition of PI3K and AMPK significantly reduced IGFBP-2-stimulated GU. In conclusion, IGFBP-2 stimulates GU in 3T3-L1 adipocytes through activation of PI3K/Akt, AMPK/TBC1D1, and PI3K/PKCζ/λ/GLUT-4 signaling. The stimulatory effect of IGFBP-2 on GU is independent of its binding to IGF-1 and is possibly not mediated through the insulin or IGF-1 receptor. This study highlights the potential role of IGFBP-2 in glucose metabolism.

  10. The transcription factor MEF2C mediates cardiomyocyte hypertrophy induced by IGF-1 signaling

    Energy Technology Data Exchange (ETDEWEB)

    Munoz, Juan Pablo; Collao, Andres; Chiong, Mario; Maldonado, Carola; Adasme, Tatiana; Carrasco, Loreto; Ocaranza, Paula; Bravo, Roberto; Gonzalez, Leticia; Diaz-Araya, Guillermo [Centro FONDAP Estudios Moleculares de la Celula, Facultad de Medicina, Universidad de Chile, Santiago 8380492 (Chile); Facultad de Ciencias Quimicas y Farmaceuticas, Facultad de Medicina, Universidad de Chile, Santiago 8380492 (Chile); Hidalgo, Cecilia [Centro FONDAP Estudios Moleculares de la Celula, Facultad de Medicina, Universidad de Chile, Santiago 8380492 (Chile); Instituto de Ciencias Biomedicas, Facultad de Medicina, Universidad de Chile, Santiago 8380492 (Chile); Lavandero, Sergio, E-mail: slavander@uchile.cl [Centro FONDAP Estudios Moleculares de la Celula, Facultad de Medicina, Universidad de Chile, Santiago 8380492 (Chile); Facultad de Ciencias Quimicas y Farmaceuticas, Facultad de Medicina, Universidad de Chile, Santiago 8380492 (Chile); Instituto de Ciencias Biomedicas, Facultad de Medicina, Universidad de Chile, Santiago 8380492 (Chile)

    2009-10-09

    Myocyte enhancer factor 2C (MEF2C) plays an important role in cardiovascular development and is a key transcription factor for cardiac hypertrophy. Here, we describe MEF2C regulation by insulin-like growth factor-1 (IGF-1) and its role in IGF-1-induced cardiac hypertrophy. We found that IGF-1 addition to cultured rat cardiomyocytes activated MEF2C, as evidenced by its increased nuclear localization and DNA binding activity. IGF-1 stimulated MEF2 dependent-gene transcription in a time-dependent manner, as indicated by increased MEF2 promoter-driven reporter gene activity; IGF-1 also induced p38-MAPK phosphorylation, while an inhibitor of p38-MAPK decreased both effects. Additionally, inhibitors of phosphatidylinositol 3-kinase and calcineurin prevented IGF-1-induced MEF2 transcriptional activity. Via MEF2C-dependent signaling, IGF-1 also stimulated transcription of atrial natriuretic factor and skeletal {alpha}-actin but not of fos-lux reporter genes. These novel data suggest that MEF2C activation by IGF-1 mediates the pro-hypertrophic effects of IGF-1 on cardiac gene expression.

  11. The transcription factor MEF2C mediates cardiomyocyte hypertrophy induced by IGF-1 signaling

    International Nuclear Information System (INIS)

    Munoz, Juan Pablo; Collao, Andres; Chiong, Mario; Maldonado, Carola; Adasme, Tatiana; Carrasco, Loreto; Ocaranza, Paula; Bravo, Roberto; Gonzalez, Leticia; Diaz-Araya, Guillermo; Hidalgo, Cecilia; Lavandero, Sergio

    2009-01-01

    Myocyte enhancer factor 2C (MEF2C) plays an important role in cardiovascular development and is a key transcription factor for cardiac hypertrophy. Here, we describe MEF2C regulation by insulin-like growth factor-1 (IGF-1) and its role in IGF-1-induced cardiac hypertrophy. We found that IGF-1 addition to cultured rat cardiomyocytes activated MEF2C, as evidenced by its increased nuclear localization and DNA binding activity. IGF-1 stimulated MEF2 dependent-gene transcription in a time-dependent manner, as indicated by increased MEF2 promoter-driven reporter gene activity; IGF-1 also induced p38-MAPK phosphorylation, while an inhibitor of p38-MAPK decreased both effects. Additionally, inhibitors of phosphatidylinositol 3-kinase and calcineurin prevented IGF-1-induced MEF2 transcriptional activity. Via MEF2C-dependent signaling, IGF-1 also stimulated transcription of atrial natriuretic factor and skeletal α-actin but not of fos-lux reporter genes. These novel data suggest that MEF2C activation by IGF-1 mediates the pro-hypertrophic effects of IGF-1 on cardiac gene expression.

  12. Distribution and levels of [125I]IGF-I, [125I]IGF-II and [125I]insulin receptor binding sites in the hippocampus of aged memory-unimpaired and -impaired rats

    International Nuclear Information System (INIS)

    Quirion, R.; Rowe, W.; Kar, S.; Dore, S.

    1997-01-01

    The insulin-like growth factors (IGF-I and IGF-II) and insulin are localized within distinct brain regions and their respective functions are mediated by specific membrane receptors. High densities of binding sites for these growth factors are discretely and differentially distributed throughout the brain, with prominent levels localized to the hippocampal formation. IGFs and insulin, in addition to their growth promoting actions, are considered to play important roles in the development and maintenance of normal cell functions throughout life. We compared the anatomical distribution and levels of IGF and insulin receptors in young (five month) and aged (25 month) memory-impaired and memory-unimpaired male Long-Evans rats as determined in the Morris water maze task in order to determine if alterations in IGF and insulin activity may be related to the emergence of cognitive deficits in the aged memory-impaired rat. In the hippocampus, [ 125 I]IGF-I receptors are concentrated primarily in the dentate gyrus (DG) and the CA3 sub-field while high amounts of [ 125 I]IGF-II binding sites are localized to the pyramidal cell layer, and the granular cell layer of the DG. [ 125 I]insulin binding sites are mostly found in the molecular layer of the DG and the CA1 sub-field. No significant differences were found in [ 125 I]IGF-I, [ 125 I]IGF-II or [ 125 I]insulin binding levels in any regions or laminae of the hippocampus of young vs aged rats, and deficits in cognitive performance did not relate to altered levels of these receptors in aged memory-impaired vs aged memory-unimpaired rats. Other regions, including various cortical areas, were also examined and failed to reveal any significant differences between the three groups studied.It thus appears that IGF-I, IGF-II and insulin receptor sites are not markedly altered during the normal ageing process in the Long-Evans rat, in spite of significant learning deficits in a sub-group (memory-impaired) of aged animals. Hence

  13. Isolation of an inhibitory insulin-like growth factor (IGF) binding protein from bone cell-conditioned medium: A potential local regulator of IGF action

    International Nuclear Information System (INIS)

    Mohan, S.; Bautista, C.M.; Wergedal, J.; Baylink, D.J.

    1989-01-01

    Inhibitory insulin-like growth factor binding protein (In-IGF-BP) has been purified to homogeneity from medium conditioned by TE89 human osteosarcoma cells by two different methods using Sephadex G-100 gel filtration, FPLC Mono Q ion-exchange, HPLC C 4 reverse-phase, HPLC CN reverse-phase and affinity chromatographies. In-IGF-BP thus purified appeared to be homogeneous and unique by the following criteria. (i) N-terminal sequence analysis yielded a unique sequence (Asp-Glu-Ala-Ile-His-Cys-Pro-Pro-Glu-Ser-Glu-Ala-Lys-Leu-Ala). (ii) Amino acid composition of In-IGF-BP revealed marked differences with the amino acid compositions of other known PBs. (iii) In-IGF-BP exhibited a single band with molecular mass of 25 kDa under reducing conditions on sodium dodecyl sulfate/polyacrylamide gels. IGF-I and IGF-II but not insulin displaced the binding of 125 I-labeled IGF-I or 125 I-labeled IGF-II binding to In-IGF-BP. In-IGF-BP inhibited basal, IGF-stimulated bone cell proliferation and serum-stimulated bone cell proliferation. Forskolin increases synthesis of In-IGF-BP in TE85 human osteosarcoma cells in a dose-dependent manner. Based on these findings, the authors conclude that In-IGF-BP is a protein that has a unique sequence and significant biological actions on bone cells

  14. BRCA1 is expressed in uterine serous carcinoma (USC) and controls insulin-like growth factor I receptor (IGF-IR) gene expression in USC cell lines.

    Science.gov (United States)

    Amichay, Keren; Kidron, Debora; Attias-Geva, Zohar; Schayek, Hagit; Sarfstein, Rive; Fishman, Ami; Werner, Haim; Bruchim, Ilan

    2012-06-01

    The insulin-like growth factor I receptor (IGF-IR) and BRCA1 affect cell growth and apoptosis. Little information is available about BRCA1 activity on the IGF signaling pathway. This study evaluated the effect of BRCA1 on IGF-IR expression. BRCA1 and IGF-IR immunohistochemistry on archival tissues (35 uterine serous carcinomas [USCs] and 17 metastases) were performed. USPC1 and USPC2 cell lines were transiently cotransfected with an IGF-IR promoter construct driving a luciferase reporter gene and a BRCA1 expression plasmid. Endogenous IGF-IR levels were evaluated by Western immunoblotting. We found high BRCA1 and IGF-IR protein expression in primary and metastatic USC tumors. All samples were immunostained for BRCA1-71% strongly stained; and 33/35 (94%) were stained positive for IGF-IR-2 (6%) strongly stained. No difference in BRCA1 and IGF-IR staining intensity was noted between BRCA1/2 mutation carriers and noncarriers. Metastatic tumors stained more intensely for BRCA1 than did the primary tumor site (P = 0.041) and with borderline significance for IGF-IR (P = 0.069). BRCA1 and IGF-IR staining did not correlate to survival. BRCA1 expression led to 35% and 54% reduction in IGF-IR promoter activity in the USPC1 and USCP2 cell lines, respectively. Western immunoblotting showed a decline in phosphorylated IGF-IR and phosphorylated AKT in both transiently and stably transfected cells. BRCA1 and IGF-IR are highly expressed in USC tumors. BRCA1 suppresses IGF-IR gene expression and activity. These findings suggest a possible biological link between the BRCA1 and the IGF-I signaling pathways in USC. The clinical implications of this association need to be explored.

  15. Bioactive insulin-like growth factor (IGF) I and IGF-binding protein-1 in anorexia nervosa

    DEFF Research Database (Denmark)

    Støving, René; Chen, Jian-Wen; Glintborg, Dorte

    2007-01-01

    CONTEXT: Regulation of IGF-I activity appears crucial in anorexia nervosa (AN) during adaptation to chronic starvation as well as during the regenerative processes on nutritional restoration. OBJECTIVE: The objective of this study was to examine the relationship between IGF-I bioactivity and IGF...

  16. Bone Growth, Mechanical Stimulus and IGF-I

    National Research Council Canada - National Science Library

    Gilsanz, Vicente

    2002-01-01

    ... exercise intervention or no intervention. This study also examines the possible relations between the cross-sectional properties of bone and circulating levels of IGF-I, JGF-binding protein-3, and IGF-I genotypes in teenagers...

  17. Common elements in interleukin 4 and insulin signaling pathways in factor-dependent hematopoietic cells.

    Science.gov (United States)

    Wang, L M; Keegan, A D; Li, W; Lienhard, G E; Pacini, S; Gutkind, J S; Myers, M G; Sun, X J; White, M F; Aaronson, S A

    1993-05-01

    Interleukin 4 (IL-4), insulin, and insulin-like growth factor I (IGF-I) efficiently induced DNA synthesis in the IL-3-dependent murine myeloid cell lines FDC-P1 and FDC-P2. Although these factors could not individually sustain long-term growth of these lines, a combination of IL-4 with either insulin or IGF-I did support continuous growth. The principal tyrosine-phosphorylated substrate observed in FDC cells stimulated with IL-4, previously designated 4PS, was of the same size (170 kDa) as the major substrate phosphorylated in response to insulin or IGF-I. These substrates had phosphopeptides of the same size when analyzed by digestion with Staphylococcus aureus V8 protease, and each tightly associated with the 85-kDa component of phosphatidylinositol 3-kinase after factor stimulation. IRS-1, the principal substrate phosphorylated in response to insulin or IGF-I stimulation in nonhematopoietic cells, is similar in size to 4PS. However, anti-IRS-1 antibodies failed to efficiently precipitate 4PS, and some phosphopeptides generated by V8 protease digestion of IRS-1 were distinct in size from the phosphopeptides of 4PS. Nevertheless, IL-4, insulin, and IGF-I were capable of stimulating tyrosine phosphorylation of IRS-1 in FDC cells that expressed this substrate as a result of transfection. These findings indicate that (i) IL-4, insulin, and IGF-I use signal transduction pathways in FDC lines that have at least one major feature in common, the rapid tyrosine phosphorylation of 4PS, and (ii) insulin and IGF-I stimulation of hematopoietic cell lines leads to the phosphorylation of a substrate that may be related to but is not identical to IRS-1.

  18. Role of IGF-I Signaling in Muscle Bone Interactions

    Science.gov (United States)

    Bikle, Daniel D; Tahimic, Candice; Chang, Wenhan; Wang, Yongmei; Philippou, Anastassios; Barton, Elisabeth R.

    2015-01-01

    Skeletal muscle and bone rely on a number of growth factors to undergo development, modulate growth, and maintain physiological strength. A major player in these actions is insulin-like growth factor I (IGF-I). However, because this growth factor can directly enhance muscle mass and bone density, it alters the state of the musculoskeletal system indirectly through mechanical crosstalk between these two organ systems. Thus, there are clearly synergistic actions of IGF-I that extend beyond the direct activity through its receptor. This review will cover the production and signaling of IGF-I as it pertains to muscle and bone, the chemical and mechanical influences that arise from IGF-I activity, and the potential for therapeutic strategies based on IGF-I. PMID:26453498

  19. Monoclonal antibodies directed to human insulin-like growth factor I (IGF I)

    International Nuclear Information System (INIS)

    Laubli, U.K.; Baier, W.; Celio, M.R.; Binz, H.; Humbel, R.E.

    1982-01-01

    Mouse hybridomas secreting antibodies to human insulin-like growth factor I (IGF I) were produced by fusion of spleen cells of hyperimmunised mice with FO mouse-myeloma cells. Eight clones producing antibodies against human IGF I have been isolated, two of which have been characterised. One was used in a radioimmunoassay, the other for immunopurification of IGF. (Auth.)

  20. Effect of Modified and accumulated decoction on serum ER, PR, sex hormone, IGF-I and IGF-I in patients with uterine fibroids

    Directory of Open Access Journals (Sweden)

    Yi-Sha Li

    2017-11-01

    Full Text Available Objective: To study the effect of Modified and accumulated Decoction on serum ER, PR, sex hormone, IGF-I and IGF-I in patients with uterine fibroids. Method: A total of 90 patients with uterine fibroids in our hospital from January 2015 to January 2017 were enrolled in this study. The subjects were divided into the control group (n=45 and the treatment group (n=45 randomly. The control group was treated with mifepristone, the treatment group was treated with Modified and accumulated Decoction combined with mifepristone, and both the two groups were treated for 3 months. The uterine fibroid volume and uterine volume of the two groups before and after treatment were compared. The serum ER, PR, P, E 2 , LH, FSH, IGF-I and IGF-IR of the two groups before and after treatment were compared. Result: There were no significantly differences of the uterine fibroid volume and uterine volume of the two groups before treatment. The uterine fibroid volume and uterine volume of the two groups after treatment were significantly less than before treatment, and that of the treatment group after treatment were significantly less than the control group. There were no significantly differences among the serum ER, PR, P, E 2 , LH, FSH, IGF-I and IGF-IR of the two groups before treatment. The serum ER, PR, P, E 2 , LH, FSH, IGF-I and IGF-IR of the two groups after treatment were significantly lower than before treatment, and that of the treatment group after treatment were significantly lower than the control group. Conclusion: Modified and accumulated Decoction combined with mifepristonecan significantly reduce the uterine fibroid volume, improve the serum ER, PR, sex hormone, IGF-I and IGF-I levels of the patients with uterine fibroids, and it was worthy clinical application.

  1. Distinct signalling properties of insulin receptor substrate (IRS)-1 and IRS-2 in mediating insulin/IGF-1 action

    DEFF Research Database (Denmark)

    Rabiee, Atefeh; Krüger, Marcus; Ardenkjær-Larsen, Jacob

    2018-01-01

    Insulin/IGF-1 action is driven by a complex and highly integrated signalling network. Loss-of-function studies indicate that the major insulin/IGF-1 receptor substrate (IRS) proteins, IRS-1 and IRS-2, mediate different biological functions in vitro and in vivo, suggesting specific signalling...... properties despite their high degree of homology. To identify mechanisms contributing to the differential signalling properties of IRS-1 and IRS-2 in the mediation of insulin/IGF-1 action, we performed comprehensive mass spectrometry (MS)-based phosphoproteomic profiling of brown preadipocytes from wild type......, IRS-1-/-and IRS-2-/-mice in the basal and IGF-1-stimulated states. We applied stable isotope labeling by amino acids in cell culture (SILAC) for the accurate quantitation of changes in protein phosphorylation. We found ~10% of the 6262 unique phosphorylation sites detected to be regulated by IGF-1...

  2. No preclinical rationale for IGF1R directed therapy in chondrosarcoma of bone.

    Science.gov (United States)

    Peterse, Elisabeth F P; Cleven, Arjen H G; De Jong, Yvonne; Briaire-de Bruijn, Inge; Fletcher, Jonathan A; Danen, Erik H J; Cleton-Jansen, Anne-Marie; Bovée, Judith V M G

    2016-07-14

    Chondrosarcoma is a malignant cartilage forming bone tumour for which no effective systemic treatment is available. Previous studies illustrate the need for a better understanding of the role of the IGF pathway in chondrosarcoma to determine if it can be a target for therapy, which was therefore explored in this study. Expression of mediators of IGF1R signalling and phosphorylation status of IRS1 was determined in chondrosarcoma cell lines by qRT-PCR and western blot. The effect of activation and inhibition of IGF1R signalling on downstream targets was assessed by western blot. Ten chondrosarcoma cell lines were treated with OSI-906 (IGF1R and IR dual inhibitor) after which cell proliferation and migration were determined by a viability assay and the xCELLigence system, respectively. In addition, four chondrosarcoma cell lines were treated with a combination of doxorubicin and OSI-906. By immunohistochemistry, IGF1R expression levels were determined in tissue microarrays of 187 cartilage tumours and ten paraffin embedded cell lines. Mediators of IGF1R signalling are heterogeneously expressed and phosphorylated IRS1 was detected in 67 % of the tested chondrosarcoma cell lines, suggesting that IGF1R signalling is active in a subset of chondrosarcoma cell lines. In the cell lines with phosphorylated IRS1, inhibition of IGF1R signalling decreased phosphorylated Akt levels and increased IGF1R expression, but it did not influence MAPK or S6 activity. In line with these findings, treatment with IGF1R/IR inhibitors did not impact proliferation or migration in any of the chondrosarcoma cell lines, even upon stimulation with IGF1. Although synergistic effects of IGF1R/IR inhibition with doxorubicin are described for other cancers, our results demonstrate that this was not the case for chondrosarcoma. In addition, we found minimal IGF1R expression in primary tumours in contrast to the high expression detected in chondrosarcoma cell lines, even if both were derived from the

  3. Nutritional regulation of IGF-II, but not IGF-I, is age dependent in sheep.

    Science.gov (United States)

    Oldham, J M; Martyn, J A; Hua, K M; MacDonald, N A; Hodgkinson, S C; Bass, J J

    1999-12-01

    In post-natal animals, plasma concentrations of IGF-I are tightly regulated by nutritional status. The current study reports that plasma levels of IGF-II in sheep are also regulated by nutrition, but whether plasma IGF-II is increased, decreased or remains the same, depends on the age of the animal. Ewe lambs, ranging in age from 2 days to 2 years, were fed or fasted for lengths of time between 24 and 72 h. Blood samples were taken at intervals of 24 h throughout the treatment period and immediately before slaughter. Plasma concentrations of IGF-I increased with advancing age in fed animals (Panimals matured (Pnutrition (Panimals (Panimals (Pnutritional sensitivity of serum IGF-binding proteins (BPs) also changed with age. The 29 kDa BP, which we presume to be BP1, was elevated by fasting in young animals and reduced slightly in older animals. BP2 was increased to a similar magnitude by fasting at all ages. BP3 was depressed by fasting in young animals and showed little change in adults. In contrast, a 24 kDa BP, which is probably BP4, showed little change in young animals and was reduced substantially in older sheep. In conclusion, the response of plasma IGF-II to fasting suggests that this peptide has functions in mediating nutritional stress which depend on the age of the animal, and also that the role of IGF-II may differ from that of IGF-I in adults.

  4. Effect of milk proteins on linear growth and IGF variables in overweight adolescents

    DEFF Research Database (Denmark)

    Larnkjær, Anni; Arnberg, Karina; Michaelsen, Kim F

    2014-01-01

    Milk may stimulate growth acting via insulin-like growth factor-I (IGF-I) secretion but the effect in adolescents is less examined. This study investigates the effect of milk proteins on linear growth, IGF-I, IGF binding protein-3 (IGFBP-3) and IGF-I/IGFBP-3 ratio in overweight adolescents....

  5. Interaction of Mechanical Load with Growth Hormone (GH) and Insulin-Like Growth Factor I (IGF-I) on Slow-Twitch Skeletal Muscle and Bone

    Science.gov (United States)

    Linderman, Jon K.; Gosselink, Kristin L.; Wang, Tommy J.; Mukku, Venkat R.; Grindeland, Richard E.

    1994-01-01

    Exogenous humoral growth factors, combined with increased mechanical loading, reportedly induce hypertrophy of fast-, but not slow-twitch skeletal muscles, and have little effect in attenuating atrophy of slow-twitch muscle associated with exposure to microgravity in animals with intact neuroendocrine systems. These observations suggest that anabolic adjuvants and muscle tension do not interact to stimulate growth or maintenance of slow-twitch skeletal muscle. The purpose of the present study was to determine whether a chronic increase in mechanical loading (synergistic ablation) or hindlimb unweighting (hindlimb suspension) interact with exogenous GH and IGF-I (Genentech, So San Francisco, CA) in the slow-twitch soleus muscles of female rats (approx. 250 g). Bilateral ablation of the plantaris and gastrocnemius muscles induced 38% and 40% increases in the absolute (mg/pair) and relative (mg/100 g body weight) weights of the soleus, respectively (p less than or = 0.05), in ambulatory rats. GH and IGF-I interacted with chronic loading to increase absolute soleus mass an additional 20% (p less than or = 0.05), and mixed and myofibrillar protein contents an additional 12% and 7%, respectively (NS). In contrast, hindlimb suspension (HLS) resulted in 20% and 18% decreases in the absolute and relative weights of the soleus, respectively (p less than or = 0.05); GH and IGF-I did not spare loss of soleus mass or protein content in HLS rats. HLS decreased tibial plate thickness approx. 11% (p less than or = 0.05), but not weights of the tibia or femus. GH and IGF-I increased tibial plate thickness approx. 30% (p less than or = 0.05), in ambulatory and HLS rats, and increased femur and tibial weights 12% (p less than or = 0.05) and 8% (NS), respectively, in ambulatory rats, but had no effect in HLS rats. Results of the present investigation suggest that GH and IGF-I can stimulate hypertrophy of slow-twitch skeletal muscle when chronically overloaded, but can also stimulate

  6. Insulin/IGF-I regulation of necdin and brown adipocyte differentiation via CREB- and FoxO1-associated pathways

    DEFF Research Database (Denmark)

    Cypess, Aaron M; Zhang, Hongbin; Schulz, Tim J

    2011-01-01

    is regulated by the phosphoinositide 3 kinase-Akt pathway, increased necdin promoter activity. Based on reporter gene assays using truncations of the necdin promoter and chromatin immunoprecipitation studies, we demonstrated that CREB and FoxO1 are recruited to the necdin promoter, likely interacting......Brown adipose tissue plays an important role in obesity, insulin resistance, and diabetes. We have previously shown that the transition from brown preadipocytes to mature adipocytes is mediated in part by insulin receptor substrate (IRS)-1 and the cell cycle regulator protein necdin. In this study...... with specific consensus sequences in the proximal region. Based on these results, we propose that insulin/IGF-I act through IRS-1 phosphorylation to stimulate differentiation of brown preadipocytes via two complementary pathways: 1) the Ras-ERK1/2 pathway to activate CREB and 2) the phosphoinositide 3 kinase-Akt...

  7. Serum tree IGF-I, total IGF-I, IGFBP-1 and IGFBP-3 levels in an elderly population : relation to age and sex steroid levels

    NARCIS (Netherlands)

    Janssen, JAMJL; Stolk, RP; Pols, HAP; Grobbee, DE; de Jong, FH; Lamberts, SWJ

    BACKGROUND Most previous studies concerning the relationship between IGF-I and age used assays measuring total IGF-I, Although free IGF-I is considered of greater biological relevance, little is known about its relationship with sex steroids levels in elderly healthy subjects, MEASUREMENTS In a

  8. IGF-I replacement therapy in children with congenital IGF-I deficiency (Laron syndrome) maintains heart dimension and function.

    Science.gov (United States)

    Scheinowitz, Mickey; Feinberg, Micha S; Laron, Zvi

    2009-06-01

    Untreated patients with congenital growth hormone deficiency (GHD) and IGF-I deficiency are characterized not only by dwarfism but also by acromicria and organomicria, such as the heart. We assessed cardiac dimensions and function in very young patients with Laron syndrome (LS) undergoing IGF-I replacement therapy. Two to seven echocardiographic measurements were performed during IGF-I replacement therapy on male (n=4) and female (n=4) LS -patients, mean+/-SD age of 7.1+/-3.6 years (range 1.6-11.6 years), weight 16.1+/-9.7 kg, and height 89.9+/-18.5 cm. As aged- and gender-matched controls served 44 healthy children, age: 8.7+/-5.5 years, weight: 36.1+/-22.4 kg, and height: 129.7+/-33.1cm. Data of LS patients were normalized to body surface area and compared to the control group as well as nomograms of normal echocardiographic parameters for this age group. Left ventricular diastolic and systolic dimensions (LVDD/ LVSD, mm) and LV mass (gr) were significantly smaller in boys and girls with IGF-I treated LS compared with controls while the shortening fraction (%) and intraventricular septum thickness (mm) were similar. When compared with standard values for this age group, all treated LS patients were within 1 standard deviation of the mean. IGF-I therapy of young patients with Laron syndrome maintain LV dimensions and function within the normal range of aged-matched controls.

  9. Compensatory growth assessment by plasma IGF-I hormone ...

    African Journals Online (AJOL)

    USER

    2010-06-21

    Jun 21, 2010 ... feeding diets and regimes will be evaluated in future studies. Key words: Compensatory growth, food coefficient ratio, food intake, IGF-I, rainbow trout, special growth .... Blood was sampled for IGF-I hormone concentration.

  10. The Association Between IGF-I and Insulin Resistance

    DEFF Research Database (Denmark)

    Friedrich, Nele; Thuesen, Betina; Jørgensen, Torben

    2012-01-01

    OBJECTIVEIGF-I has an almost 50% amino acid sequence homology with insulin and elicits nearly the same hypoglycemic response. Studies showed that low and high IGF-I levels are related to impaired glucose tolerance and to a higher risk of type 2 diabetes. The aim of the current study was to evaluate...... the association between IGF-I level and insulin resistance in a Danish general population.RESEARCH DESIGN AND METHODSIncluded were 3,354 adults, aged 19-72 years, from the cross-sectional Health2006 study. The homeostasis model assessment of insulin resistance (HOMA-IR) was used as the index to estimate insulin...... with intermediate (Q3) IGF-I levels. These associations remained statistically significant after the exclusion of subjects with type 2 diabetes and by using the updated computer HOMA2-IR model.CONCLUSIONSLow- and high-normal IGF-I levels are both related to insulin resistance. The biological mechanism...

  11. Regulation of hypoxia-inducible factor-1α (HIF-1α expression by interleukin-1β (IL-1 β, insulin-like growth factors I (IGF-I and II (IGF-II in human osteoarthritic chondrocytes

    Directory of Open Access Journals (Sweden)

    Angelica Rossi Sartori-Cintra

    2012-01-01

    Full Text Available OBJECTIVE: Hypoxia-inducible factor 1 alpha regulates genes related to cellular survival under hypoxia. This factor is present in osteroarthritic chondrocytes, and cytokines, such as interleukin-1 beta, participate in the pathogenesis of osteoarthritis, thereby increasing the activities of proteolytic enzymes, such as matrix metalloproteinases, and accelerating cartilage destruction. We hypothesize that Hypoxia Inducible Factor-1 alpha (HIF-1α can regulate cytokines (catabolic action and/or growth factors (anabolic action in osteoarthritis. The purpose of this study was to investigate the modulation of HIF-1α in human osteoarthritic chondrocytes by interleukin-1 beta (IL-1β and insulin-like growth factors I (IGF-I and II (IGF-II and to determine the involvement of the phosphatidylinositol-3kinase (PI-3K pathway in this process. METHODS: Human osteroarthritic chondrocytes were stimulated with IL-1β, IGF-I and IGF-II and LY294002, a specific inhibitor of PI-3K. Nuclear protein levels and gene expression were analyzed by western blot and quantitative reverse transcription-polymerase chain reaction analyses, respectively. RESULTS: HIF-1α expression was upregulated by IL-1β at the protein level but not at the gene level. IGF-I treatment resulted in increases in both the protein and mRNA levels of HIF-1α , whereas IGF-II had no effect on its expression. However, all of these stimuli exploited the PI-3K pathway. CONCLUSION: IL-1β upregulated the levels of HIF-1α protein post-transcriptionally, whereas IGF-I increased HIF-1α at the transcript level. In contrast, IGF-II did not affect the protein or gene expression levels of HIF-1α . Furthermore, all of the tested stimuli exploited the PI-3K pathway to some degree. Based on these findings, we are able to suggest that Hypoxia inducible Factor-1 exhibits protective activity in chondrocytes during osteoarthritis.

  12. Effects of dietary carbohydrate sources on plasma glucose, insulin and IGF-I levels in multiparous sows

    NARCIS (Netherlands)

    Wientjes, J.G.M.; Soede, N.M.; Aarsse, F.; Laurenssen, B.F.A.; Koopmanschap, R.E.; Brand, van den H.; Kemp, B.

    2012-01-01

    Effects of different carbohydrate sources on plasma glucose, insulin and insulin-like growth factor-I (IGF-I) levels were compared to subsequently be able to study effects of insulin-stimulating diets on follicle development in sows. The following feed components were tested in 12 sows during six

  13. PAPP-A proteolytic activity enhances IGF bioactivity in ascites from women with ovarian carcinoma

    Science.gov (United States)

    Thomsen, Jacob; Hjortebjerg, Rikke; Espelund, Ulrick; Ørtoft, Gitte; Vestergaard, Poul; Magnusson, Nils E.; Conover, Cheryl A.; Tramm, Trine; Hager, Henrik; Høgdall, Claus; Høgdall, Estrid; Oxvig, Claus; Frystyk, Jan

    2015-01-01

    Pregnancy-associated plasma protein-A (PAPP-A) stimulates insulin-like growth factor (IGF) action through proteolysis of IGF-binding protein (IGFBP)-4. In experimental animals, PAPP-A accelerates ovarian tumor growth by this mechanism. To investigate the effect of PAPP-A in humans, we compared serum and ascites from 22 women with ovarian carcinoma. We found that ascites contained 46-fold higher PAPP-A levels as compared to serum (P IGF-I receptor (IGF-IR) in vitro (+31%, P IGF-I, and lower levels of IGF-II (P IGF-IR in all but one tumor, whereas all tumors expressed PAPP-A, IGFBP-4, IGF-I and IGF-II. Addition of recombinant PAPP-A to ascites increased the cleavage of IGFBP-4 and enhanced IGF-IR activation (P IGFs and these proteins are also present in ascites. We suggest that both soluble PAPP-A in ascites and tissue-associated PAPP-A serve to increase IGF bioactivity and, thereby, to stimulate IGF-IR-mediated tumor growth. PMID:26336825

  14. No preclinical rationale for IGF1R directed therapy in chondrosarcoma of bone

    International Nuclear Information System (INIS)

    Peterse, Elisabeth F. P.; Cleven, Arjen H. G.; De Jong, Yvonne; Briaire-de Bruijn, Inge; Fletcher, Jonathan A.; Danen, Erik H. J.; Cleton-Jansen, Anne-Marie; Bovée, Judith V. M. G.

    2016-01-01

    Chondrosarcoma is a malignant cartilage forming bone tumour for which no effective systemic treatment is available. Previous studies illustrate the need for a better understanding of the role of the IGF pathway in chondrosarcoma to determine if it can be a target for therapy, which was therefore explored in this study. Expression of mediators of IGF1R signalling and phosphorylation status of IRS1 was determined in chondrosarcoma cell lines by qRT-PCR and western blot. The effect of activation and inhibition of IGF1R signalling on downstream targets was assessed by western blot. Ten chondrosarcoma cell lines were treated with OSI-906 (IGF1R and IR dual inhibitor) after which cell proliferation and migration were determined by a viability assay and the xCELLigence system, respectively. In addition, four chondrosarcoma cell lines were treated with a combination of doxorubicin and OSI-906. By immunohistochemistry, IGF1R expression levels were determined in tissue microarrays of 187 cartilage tumours and ten paraffin embedded cell lines. Mediators of IGF1R signalling are heterogeneously expressed and phosphorylated IRS1 was detected in 67 % of the tested chondrosarcoma cell lines, suggesting that IGF1R signalling is active in a subset of chondrosarcoma cell lines. In the cell lines with phosphorylated IRS1, inhibition of IGF1R signalling decreased phosphorylated Akt levels and increased IGF1R expression, but it did not influence MAPK or S6 activity. In line with these findings, treatment with IGF1R/IR inhibitors did not impact proliferation or migration in any of the chondrosarcoma cell lines, even upon stimulation with IGF1. Although synergistic effects of IGF1R/IR inhibition with doxorubicin are described for other cancers, our results demonstrate that this was not the case for chondrosarcoma. In addition, we found minimal IGF1R expression in primary tumours in contrast to the high expression detected in chondrosarcoma cell lines, even if both were derived from the

  15. IGF1 stimulates greater muscle hypertrophy in the absence of myostatin in male mice

    Science.gov (United States)

    Insulin-like growth factors (IGFs) and myostatin have opposing roles in regulating the growth and size of skeletal muscle, with IGF1 stimulating, and myostatin inhibiting, growth. However, it remains unclear whether these proteins have mutually dependent, or independent, roles. To clarify this issue...

  16. Potency of full-length MGF to induce maximal activation of the IGF-I R Is similar to recombinant human IGF-I at high equimolar concentrations

    NARCIS (Netherlands)

    J.A.M.J.L. Janssen (Joseph); L.J. Hofland (Leo); C.J. Strasburger; E.S.R.D. Van Dungen (Elisabeth S.R. Den); M. Thevis (Mario)

    2016-01-01

    textabstractAims To compare full-length mechano growth factor (full-length MGF) with human recombinant insulin-like growth factor-I (IGF-I) and human recombinant insulin (HI) in their ability to activate the human IGF-I receptor (IGF-IR), the human insulin receptor (IR-A) and the human insulin

  17. Cdc25A promotes cell survival by stimulating NF-{kappa}B activity through I{kappa}B-{alpha} phosphorylation and destabilization

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Hey-Young; Choi, Jiyeon [Department of Biochemistry, College of Natural Sciences, Kangwon National University, 192-1 Hyoja-2-dong, Chuncheon 200-701 (Korea, Republic of); Cho, Young-Wook [Korea Basic Science Institute, Chuncheon Center, Gangwondaehak-gil 1, Chuncheon 200-701 (Korea, Republic of); Kim, Byung-Chul, E-mail: bckim@kangwon.ac.kr [Department of Biochemistry, College of Natural Sciences, Kangwon National University, 192-1 Hyoja-2-dong, Chuncheon 200-701 (Korea, Republic of)

    2012-04-06

    Highlights: Black-Right-Pointing-Pointer We examine the antiapoptotic mechanisms of Cdc25A. Black-Right-Pointing-Pointer Smad7 decreases the phosphorylation of I{kappa}B-alpha at Ser-32. Black-Right-Pointing-Pointer Smad7 positively regulates NF-{kappa}B activity through I{kappa}B-alpha ubiquitination. -- Abstract: Cell division cycle 25A (Cdc25A), a dual specificity protein phosphatase, exhibits anti-apoptotic activity, but the underlying molecular mechanisms are poorly characterized. Here we report that Cdc25A inhibits cisplatin-induced apoptotic cell death by stimulating nuclear factor-kappa B (NF-{kappa}B) activity. In HEK-293 cells, Cdc25A decreased protein level of inhibitor subunit kappa B alpha (I{kappa}-B{alpha}) in association with increased serine 32-phosphorylation, followed by stimulation of transcriptional activity of NF-{kappa}B. Inhibition of NF-{kappa}B activity by chemical inhibitor or overexpression of I{kappa}-B{alpha} in Cdc25A-elevated cancer cells resistant to cisplatin improved their sensitivity to cisplatin-induced apoptosis. Our data show for the first time that Cdc25A has an important physiological role in NF-{kappa}B activity regulation and it may be an important survival mechanism of cancer cells.

  18. IGF-I levels reflect hypopituitarism severity in adults with pituitary dysfunction.

    Science.gov (United States)

    Tirosh, Amit; Toledano, Yoel; Masri-Iraqi, Hiba; Eizenberg, Yoav; Tzvetov, Gloria; Hirsch, Dania; Benbassat, Carlos; Robenshtok, Eyal; Shimon, Ilan

    2016-08-01

    To evaluate the utility of Insulin-like growth factor I (IGF-I) standard deviation score (SDS) as a surrogate marker of severity of hypopituitarism in adults with pituitary pathology. We performed a retrospective data analysis, including 269 consecutive patients with pituitary disease attending a tertiary endocrine clinic in 1990-2015. The medical files were reviewed for the complete pituitary hormone profile, including IGF-I, and clinical data. Age-adjusted assay reference ranges of IGF-I were used to calculate IGF-I SDS for each patient. The main outcome measures were positive and negative predictive values of low and high IGF-I SDS, respectively, for the various pituitary hormone deficiencies. IGF-I SDS correlated negatively with the number of altered pituitary axes (p hypopituitarism in adults with pituitary disease, and thus can serve as a marker of hypopituitarism severity.

  19. SERUM IGF-I AND HORMONAL RESPONSES TO INCREMENTAL EXERCISE IN ATHLETES WITH AND WITHOUT LEFT VENTRICULAR HYPERTROPHY

    Directory of Open Access Journals (Sweden)

    Aleksandra Zebrowska

    2009-03-01

    Full Text Available We investigated the response of insulin-like growth factor (IGF- I, insulin-like growth factor binding protein-3 (IGFBP-3 and some hormones, i.e., testosterone (T, growth hormone (GH, cortisol (C, and insulin (I, to maximal exercise in road cyclists with and without diagnosed left ventricular hypertrophy. M-mode and two-dimensional Doppler echocardiography was performed in 30 professional male endurance athletes and a group of 14 healthy untrained subjects using a Hewlett-Packard Image Point HX ultrasound system with standard imaging transducers. Echocardiography and an incremental physical exercise test were performed during the competitive season. Venous blood samples were drawn before and immediately after the maximal cycling exercise test for determination of somatomedin and hormonal concentrations. The basal concentration of IGF-I was statistically higher (p < 0.05 in athletes with left ventricular muscle hypertrophy (LVH when compared to athletes with a normal upper limit of the left ventricular wall (LVN (p < 0.05 and to the control group (CG (p < 0.01. The IGF-I level increased significantly at maximal intensity of incremental exercise in CG (p < 0.01, LVN (p < 0.05 and LVH (p < 0.05 compared to respective values at rest. Long-term endurance training induced an increase in resting (p < 0.01 and post-exercise (p < 0.05 IGF-I/IGFBP-3 ratio in athletes with LVH compared to LVN. The testosterone (T level was lower in LVH at rest compared to LVN and CG groups (p < 0.05. These results indicate that resting serum IGF-I concentration were higher in trained subjects with LVH compared to athletes without LVH. Serum IGF- I/IGFBP-3 elevation at rest and after exercise might suggest that IGF-I act as a potent stimulant of left ventricular hypertrophy in chronically trained endurance athletes

  20. Low Circulating IGF-I Bioactivity in Elderly Men is associated with Increased Mortality

    NARCIS (Netherlands)

    M.P. Brugts (Michael); A.W. van den Beld (Annewieke); L.J. Hofland (Leo); K. van der Wansem (Katy); P.M. van Koetsveld (Peter); J. Frystyk (Jan); S.W.J. Lamberts (Steven); J.A.M.J.L. Janssen (Joseph)

    2008-01-01

    textabstractContext: Low IGF-I signaling activity prolongs lifespan in certain animal models, but the precise role of IGF-I in human survival remains controversial. The IGF-I kinase receptor activation assay (IGF-I KIRA) is a novel method for measuring IGF-I bioactivity in human serum. We

  1. Deficiency of liver-derived insulin-like growth factor-I (IGF-I) does not interfere with the skin wound healing rate

    Science.gov (United States)

    Narayanan, Sampath; Grünler, Jacob; Sunkari, Vivekananda Gupta; Calissendorff, Freja S.; Ansurudeen, Ishrath; Illies, Christopher; Svensson, Johan; Jansson, John-Olov; Ohlsson, Claes; Brismar, Kerstin; Catrina, Sergiu-Bogdan

    2018-01-01

    Objective IGF-I is a growth factor, which is expressed in virtually all tissues. The circulating IGF-I is however derived mainly from the liver. IGF-I promotes wound healing and its levels are decreased in wounds with low regenerative potential such as diabetic wounds. However, the contribution of circulating IGF-I to wound healing is unknown. Here we investigated the role of systemic IGF-I on wound healing rate in mice with deficiency of liver-derived IGF-I (LI-IGF-I-/- mice) during normal (normoglycemic) and impaired wound healing (diabetes). Methods LI-IGF-I-/- mice with complete inactivation of the IGF-I gene in the hepatocytes were generated using the Cre/loxP recombination system. This resulted in a 75% reduction of circulating IGF-I. Diabetes was induced with streptozocin in both LI-IGF-I-/- and control mice. Wounds were made on the dorsum of the mice, and the wound healing rate and histology were evaluated. Serum IGF-I and GH were measured by RIA and ELISA respectively. The expression of IGF-I, IGF-II and the IGF-I receptor in the skin were evaluated by qRT-PCR. The local IGF-I protein expression in different cell types of the wounds during wound healing process was analyzed using immunohistochemistry. Results The wound healing rate was similar in LI-IGF-I-/- mice to that in controls. Diabetes significantly delayed the wound healing rate in both LI-IGF-I-/- and control mice. However, no significant difference was observed between diabetic animals with normal or reduced hepatic IGF-I production. The gene expression of IGF-I, IGF-II and IGF-I receptor in skin was not different between any group of animals tested. Local IGF-I levels in the wounds were similar between of LI-IGF-I-/- and WT mice although a transient reduction of IGF-I expression in leukocytes in the wounds of LI-IGF-I-/- was observed seven days post wounding. Conclusion Deficiency in the liver-derived IGF-I does not affect wound healing in mice, neither in normoglycemic conditions nor in

  2. mTOR complex 2 phosphorylates IMP1 cotranslationally to promote IGF2 production and the proliferation of mouse embryonic fibroblasts

    DEFF Research Database (Denmark)

    Dai, Ning; Christiansen, Jan; Nielsen, Finn

    2013-01-01

    uncover a new mechanism by which mTOR regulates organismal growth by promoting IGF2 production in the mouse embryo through mTORC2-catalyzed cotranslational IMP1/IMP3 phosphorylation. Inasmuch as TORC2 is activated by association with ribosomes, the present results indicate that mTORC2-catalyzed...... production, and diminished proliferation. The proliferation of the IMP1-null fibroblasts can be restored to wild-type levels by IGF2 in vitro or by re-expression of IMP1, which corrects the defects in IGF2 RNA splicing and translation. The ability of IMP1 to correct these defects is dependent on IMP1...

  3. Small interfering RNA targeted to IGF-IR delays tumor growth and induces proinflammatory cytokines in a mouse breast cancer model.

    Directory of Open Access Journals (Sweden)

    Tiphanie Durfort

    Full Text Available Insulin-like growth factor I (IGF-I and its type I receptor (IGF-IR play significant roles in tumorigenesis and in immune response. Here, we wanted to know whether an RNA interference approach targeted to IGF-IR could be used for specific antitumor immunostimulation in a breast cancer model. For that, we evaluated short interfering RNA (siRNAs for inhibition of in vivo tumor growth and immunological stimulation in immunocompetent mice. We designed 2'-O-methyl-modified siRNAs to inhibit expression of IGF-IR in two murine breast cancer cell lines (EMT6, C4HD. Cell transfection of IGF-IR siRNAs decreased proliferation, diminished phosphorylation of downstream signaling pathway proteins, AKT and ERK, and caused a G0/G1 cell cycle block. The IGF-IR silencing also induced secretion of two proinflammatory cytokines, TNF- α and IFN-γ. When we transfected C4HD cells with siRNAs targeting IGF-IR, mammary tumor growth was strongly delayed in syngenic mice. Histology of developing tumors in mice grafted with IGF-IR siRNA treated C4HD cells revealed a low mitotic index, and infiltration of lymphocytes and polymorphonuclear neutrophils, suggesting activation of an antitumor immune response. When we used C4HD cells treated with siRNA as an immunogen, we observed an increase in delayed-type hypersensitivity and the presence of cytotoxic splenocytes against wild-type C4HD cells, indicative of evolving immune response. Our findings show that silencing IGF-IR using synthetic siRNA bearing 2'-O-methyl nucleotides may offer a new clinical approach for treatment of mammary tumors expressing IGF-IR. Interestingly, our work also suggests that crosstalk between IGF-I axis and antitumor immune response can mobilize proinflammatory cytokines.

  4. The insulin and IGF1 receptor kinase domains are functional dimers in the activated state

    Science.gov (United States)

    Cabail, M. Zulema; Li, Shiqing; Lemmon, Eric; Bowen, Mark E.; Hubbard, Stevan R.; Miller, W. Todd

    2015-03-01

    The insulin receptor (IR) and insulin-like growth factor-1 receptor (IGF1R) are highly related receptor tyrosine kinases with a disulfide-linked homodimeric architecture. Ligand binding to the receptor ectodomain triggers tyrosine autophosphorylation of the cytoplasmic domains, which stimulates catalytic activity and creates recruitment sites for downstream signalling proteins. Whether the two phosphorylated tyrosine kinase domains within the receptor dimer function independently or cooperatively to phosphorylate protein substrates is not known. Here we provide crystallographic, biophysical and biochemical evidence demonstrating that the phosphorylated kinase domains of IR and IGF1R form a specific dimeric arrangement involving an exchange of the juxtamembrane region proximal to the kinase domain. In this dimer, the active position of α-helix C in the kinase N lobe is stabilized, which promotes downstream substrate phosphorylation. These studies afford a novel strategy for the design of small-molecule IR agonists as potential therapeutic agents for type 2 diabetes.

  5. IGF-I and IGFBP2 in peripheral artery disease

    DEFF Research Database (Denmark)

    Urbonaviciene, Grazina; Frystyk, Jan; Urbonavicius, Sigitas

    2014-01-01

    BACKGROUND AND OBJECTIVES: The search for novel risk factors of cardiovascular disease (CVD) has provided valuable clinical data concerning underlying mechanism of disease. Increasing evidence indicates a possible involvement of insulin-like growth factor-I (IGF-I) and its binding protein 2 (IGFBP......-2) in the pathogenesis of CVD disorders. The aim of this study was to examine the relationship between levels of IGF-I and IGFBP-2 with all-cause and CVD mortality in a prospective study of patients with lower-extremity peripheral artery disease (PAD). METHODS AND MATERIAL: Serum IGF-I and IGFBP-2...... levels were obtained in 440 patients (257 males) with symptomatic PAD. Patients were followed for a median of 6.1 (IQ 5.1-7.2) years. The relationship between times to lethal outcome and baseline serum IGF-I and IFGBP-2 levels were examined by Cox proportional hazard analysis. The role of IFGBP-2...

  6. Postprandial hyperglycemia corrected by IGF-I (Increlex®) in Laron syndrome.

    Science.gov (United States)

    Latrech, Hanane; Simon, Albane; Beltrand, Jacques; Souberbielle, Jean-Claude; Belmejdoub, Ghizlane; Polak, Michel

    2012-01-01

    Laron syndrome is caused by a mutation in the growth hormone (GH) receptor and manifests as insulin-like growth factor-I (IGF-I) deficiency, severe short stature, and early hypoglycemia. We report a case with postprandial hyperglycemia, an abnormality not reported previously. Postprandial hyperglycemia was due to chronic IGF-I deficiency, and was reversed by IGF-I replacement therapy. A Moroccan girl referred for short stature at 7 years and 8 months of age had dwarfism [height, 78 cm (-9 SDs); weight, 10 kg (-4 SDs)], hypoglycemia, and truncal obesity. Her serum IGF-I level was very low, and her baseline serum GH level was elevated to 47 mIU/l. Molecular analysis showed a homozygous mutation in the GH receptor gene. Continuous glucose monitoring before treatment showed asymptomatic hypoglycemia with postprandial hyperglycemia (2.5 g/l, 13.75 mmol/l). Treatment with recombinant human IGF-I (mecasermin, Increlex®) was started. The blood glucose profile improved with 0.04 µg/kg/day and returned to normal with 0.12 µg/kg/day. Postprandial hyperglycemia is a metabolic consequence of chronic IGF-I deficiency. The beneficial effect of IGF-I replacement therapy may be ascribable to improved postprandial transfer of glucose. Copyright © 2012 S. Karger AG, Basel.

  7. Pea DNA topoisomerase I is phosphorylated and stimulated by casein kinase 2 and protein kinase C.

    Science.gov (United States)

    Tuteja, Narendra; Reddy, Malireddy Kodandarami; Mudgil, Yashwanti; Yadav, Badam Singh; Chandok, Meena Rani; Sopory, Sudhir Kumar

    2003-08-01

    DNA topoisomerase I catalyzes the relaxation of superhelical DNA tension and is vital for DNA metabolism; therefore, it is essential for growth and development of plants. Here, we have studied the phosphorylation-dependent regulation of topoisomerase I from pea (Pisum sativum). The purified enzyme did not show autophosphorylation but was phosphorylated in an Mg(2+)-dependent manner by endogenous protein kinases present in pea nuclear extracts. This phosphorylation was abolished with calf intestinal alkaline phosphatase and lambda phosphatase. It was also phosphorylated by exogenous casein kinase 2 (CK2), protein kinase C (PKC; from animal sources), and an endogenous pea protein, which was purified using a novel phorbol myristate acetate affinity chromatography method. All of these phosphorylations were inhibited by heparin (inhibitor of CK2) and calphostin (inhibitor of PKC), suggesting that pea topoisomerase I is a bona fide substrate for these kinases. Spermine and spermidine had no effect on the CK2-mediated phosphorylation, suggesting that it is polyamine independent. Phospho-amino acid analysis showed that only serine residues were phosphorylated, which was further confirmed using antiphosphoserine antibody. The topoisomerase I activity increased after phosphorylation with exogenous CK2 and PKC. This study shows that these kinases may contribute to the physiological regulation of DNA topoisomerase I activity and overall DNA metabolism in plants.

  8. IGF-I and NEFA concentrations in fetal fluids of term pregnancy dogs.

    Science.gov (United States)

    Meloni, Tea; Comin, Antonella; Rota, Alessandro; Peric, Tanja; Contri, Alberto; Veronesi, Maria Cristina

    2014-06-01

    Insulin-like growth factor-I (IGF-I) and non-esterified fatty acids (NEFA) play an essential role in fetal growth and development. To date, fetal fluids IGF-I and NEFA levels at term canine pregnancy are unknown and could be related to the neonatal development and breed size. For these reasons, the aims of the present study were as follows: (1) to evaluate IGF-I and NEFA concentrations in fetal fluids collected from normally developed and viable newborn puppies born at term of normal pregnancies; (2) to assess possible differences between IGF-I and NEFA levels in amniotic compared with allantoic fluid; (3) to detect possible relationship between breed body size and IGF-I and NEFA amniotic and allantoic concentrations; (4) to evaluate possible differences in IGF-I fetal fluids levels between male and female puppies; and (5) to assess possible correlations between the two hormones in each type of fluid. The study enrolled 25 pure breed bitches submitted to elective Cesarean section at term because of the high risk of dystocia or previous troubles at parturition. At surgery, amniotic and allantoic fluids were collected and assayed for IGF-I and NEFA. IGF-I and NEFA amounts in both amniotic and allantoic fluids of different breed size bitches (small: ≤10 kg; medium: 11-25 kg; large: 26-40 kg) were detected, as well as the effect of gender on IGF-I levels. On a total of 73 amniotic and 76 allantoic samples collected by normal, viable, and mature newborns, the mean IGF-I concentration was significantly higher in amniotic than in allantoic fluid in all three groups, but the amniotic IGF-I levels were significantly lower in small and medium size bitches when compared with large ones. No significant differences were found in allantoic IGF-I concentrations among size groups. A significant effect of the puppy gender on IGF-I content in both fetal fluids was not reported. Regarding NEFA, in all the three groups, the mean NEFA concentration did not significantly differ

  9. What Happened to the IGF Binding Proteins?

    Science.gov (United States)

    Bach, Leon A

    2018-02-01

    Insulinlike growth factor (IGF) binding proteins (IGFBPs) 1 to 6 are high-affinity regulators of IGF activity. They generally inhibit IGF actions by preventing binding to the IGF-I receptor but can also enhance their actions under some conditions. Posttranslational modifications such as glycosylation and phosphorylation modulate IGFBP properties, and IGFBP proteolysis results in IGF release. IGFBPs have more recently been shown to have IGF-independent actions. A number of mechanisms are involved, including modulation of other growth factor pathways, nuclear localization and transcriptional regulation, interaction with the sphingolipid pathway, and binding to non-IGF biomolecules in the extracellular space and matrix, on the cell surface and intracellularly. IGFBPs modulate important biological processes, including cell proliferation, survival, migration, senescence, autophagy, and angiogenesis. Their actions have been implicated in growth, metabolism, cancer, stem cell maintenance and differentiation, and immune regulation. Recent studies have shown that epigenetic mechanisms are involved in the regulation of IGFBP abundance. A more complete understanding of IGFBP biology is necessary to further define their cellular roles and determine their therapeutic potential. Copyright © 2018 Endocrine Society.

  10. Regulation of human trophoblast GLUT1 glucose transporter by insulin-like growth factor I (IGF-I.

    Directory of Open Access Journals (Sweden)

    Marc U Baumann

    Full Text Available Glucose transport to the fetus across the placenta takes place via glucose transporters in the opposing faces of the barrier layer, the microvillous and basal membranes of the syncytiotrophoblast. While basal membrane content of the GLUT1 glucose transporter appears to be the rate-limiting step in transplacental transport, the factors regulating transporter expression and activity are largely unknown. In view of the many studies showing an association between IGF-I and fetal growth, we investigated the effects of IGF-I on placental glucose transport and GLUT1 transporter expression. Treatment of BeWo choriocarcinoma cells with IGF-I increased cellular GLUT1 protein. There was increased basolateral (but not microvillous uptake of glucose and increased transepithelial transport of glucose across the BeWo monolayer. Primary syncytial cells treated with IGF-I also demonstrated an increase in GLUT1 protein. Term placental explants treated with IGF-I showed an increase in syncytial basal membrane GLUT1 but microvillous membrane GLUT1 was not affected. The placental dual perfusion model was used to assess the effects of fetally perfused IGF-I on transplacental glucose transport and syncytial GLUT1 content. In control perfusions there was a decrease in transplacental glucose transport over the course of the perfusion, whereas in tissues perfused with IGF-I through the fetal circulation there was no change. Syncytial basal membranes from IGF-I perfused tissues showed an increase in GLUT1 content. These results demonstrate that IGF-I, whether acting via microvillous or basal membrane receptors, increases the basal membrane content of GLUT1 and up-regulates basal membrane transport of glucose, leading to increased transepithelial glucose transport. These observations provide a partial explanation for the mechanism by which IGF-I controls nutrient supply in the regulation of fetal growth.

  11. IGF-I bioactivity might reflect different aspects of quality of life than total IGF-I in gh-deficient patients during GH treatment

    NARCIS (Netherlands)

    A.J. Varewijck (Aimee); S.W.J. Lamberts (Steven); S.J.C.M.M. Neggers (Bas); L.J. Hofland (Leo); J.A.M.J.L. Janssen (Joseph)

    2013-01-01

    textabstractContext: No relationship has been found between improvement in quality of life (QOL) and total IGF-I during GH therapy. Aim: Our aim was to investigate the relationship between IGF-I bioactivity and QOL in GH-deficient (GHD) patients receiving GH for 12 months. Methods: Of 106 GHD

  12. Diosgenin induces apoptosis in IGF-1-stimulated human thyrocytes through two caspase-dependent pathways

    International Nuclear Information System (INIS)

    Mu, Shumin; Tian, Xingsong; Ruan, Yongwei; Liu, Yuantao; Bian, Dezhi; Ma, Chunyan; Yu, Chunxiao; Feng, Mei; Wang, Furong; Gao, Ling; Zhao, Jia-jun

    2012-01-01

    Highlights: ► Diosgenin induces apoptosis in IGF-1-treated thyrocytes through two caspase pathways. ► Diosgenin inhibits FLIP and activates caspase-8 in FAS related-pathway. ► Diosgenin increases ROS, regulates the ratio of Bax/Bcl-2 in mitochondrial pathway. -- Abstract: Insulin-like growth factor-1 (IGF-1) is a growth factor of the thyroid that has been shown in our previous study to possess proliferative and antiapoptotic effects in FRTL-5 cell lines through the upregulation of cyclin D and Fas-associated death domain-like interleukin-1-converting enzyme (FLICE)-inhibitory protein (FLIP). Diosgenin, a natural steroid sapogenin from plants, has been shown to induce apoptosis in many cell lines, with the exception of thyroid cells. In this report, we investigated the apoptotic effect and mechanism of diosgenin in IGF-1-stimulated primary human thyrocytes. Primary human thyrocytes were preincubated with or without IGF-1 for 24 h and subsequently exposed to varying concentrations of diosgenin for different times. We found that diosgenin induced apoptosis in human thyrocytes pretreated with IGF-1 in a dose-dependent manner through the activation of caspase cascades. Moreover, diosgenin inhibited FLIP and activated caspase-8 in the FAS-related apoptotic pathway. Diosgenin increased the production of ROS, regulated the balance of Bax and Bcl-2 and cleaved caspase-9 in the mitochondrial apoptotic pathway. These results indicate that diosgenin induces apoptosis in IGF-1-stimulated primary human thyrocytes through two caspase-dependent pathways.

  13. Insulin-like growth factor (IGF)-I binding to a cell membrane associated IGF binding protein-3 acid-labile subunit complex in human anterior pituitary gland

    NARCIS (Netherlands)

    Wilczak, N; Kuhl, N; Chesik, D; Geerts, A; Luiten, P; De Keyser, J

    The binding characteristics of [(125) I]insulin-like growth factor (IGF)-I were studied in human brain and pituitary gland. Competition binding studies with DES(1-3)IGF-I and R-3 -IGF-I, which display high affinity for the IGF-I receptor and low affinity for IGF binding proteins (IGFBPs), were

  14. PAPP-A proteolytic activity enhances IGF bioactivity in ascites from women with ovarian carcinoma

    DEFF Research Database (Denmark)

    Thomsen, Jacob; Hjortebjerg, Rikke; Espelund, Ulrick

    2015-01-01

    Pregnancy-associated plasma protein-A (PAPP-A) stimulates insulin-like growth factor (IGF) action through proteolysis of IGF-binding protein (IGFBP)-4. In experimental animals, PAPP-A accelerates ovarian tumor growth by this mechanism. To investigate the effect of PAPP-A in humans, we compared.......03). Ascites was more potent than serum in activating the IGF-I receptor (IGF-IR) in vitro (+31%, P IGF-I, and lower levels of IGF-II (P ... of IGF-IR in all but one tumor, whereas all tumors expressed PAPP-A, IGFBP-4, IGF-I and IGF-II. Addition of recombinant PAPP-A to ascites increased the cleavage of IGFBP-4 and enhanced IGF-IR activation (P IGFs and these proteins...

  15. IGF-I enhances cellular senescence via the reactive oxygen species-p53 pathway

    Energy Technology Data Exchange (ETDEWEB)

    Handayaningsih, Anastasia-Evi; Takahashi, Michiko; Fukuoka, Hidenori; Iguchi, Genzo; Nishizawa, Hitoshi; Yamamoto, Masaaki; Suda, Kentaro [Division of Diabetes and Endocrinology, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe (Japan); Takahashi, Yutaka, E-mail: takahash@med.kobe-u.ac.jp [Division of Diabetes and Endocrinology, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe (Japan)

    2012-08-24

    Highlights: Black-Right-Pointing-Pointer Cellular senescence plays an important role in tumorigenesis and aging process. Black-Right-Pointing-Pointer We demonstrated IGF-I enhanced cellular senescence in primary confluent cells. Black-Right-Pointing-Pointer IGF-I enhanced cellular senescence in the ROS and p53-dependent manner. Black-Right-Pointing-Pointer These results may explain the underlying mechanisms of IGF-I involvement in tumorigenesis and in regulation of aging. -- Abstract: Cellular senescence is characterized by growth arrest, enlarged and flattened cell morphology, the expression of senescence-associated {beta}-galactosidase (SA-{beta}-gal), and by activation of tumor suppressor networks. Insulin-like growth factor-I (IGF-I) plays a critical role in cellular growth, proliferation, tumorigenesis, and regulation of aging. In the present study, we show that IGF-I enhances cellular senescence in mouse, rat, and human primary cells in the confluent state. IGF-I induced expression of a DNA damage marker, {gamma}H2AX, the increased levels of p53 and p21 proteins, and activated SA-{beta}-gal. In the confluent state, an altered downstream signaling of IGF-I receptor was observed. Treatment with a reactive oxygen species (ROS) scavenger, N-acetylcystein (NAC) significantly suppressed induction of these markers, indicating that ROS are involved in the induction of cellular senescence by IGF-I. In p53-null mouse embryonic fibroblasts, the IGF-I-induced augmentation of SA-{beta}-gal and p21 was inhibited, demonstrating that p53 is required for cellular senescence induced by IGF-I. Thus, these data reveal a novel pathway whereby IGF-I enhances cellular senescence in the ROS and p53-dependent manner and may explain the underlying mechanisms of IGF-I involvement in tumorigenesis and in regulation of aging.

  16. IGF-I enhances cellular senescence via the reactive oxygen species–p53 pathway

    International Nuclear Information System (INIS)

    Handayaningsih, Anastasia-Evi; Takahashi, Michiko; Fukuoka, Hidenori; Iguchi, Genzo; Nishizawa, Hitoshi; Yamamoto, Masaaki; Suda, Kentaro; Takahashi, Yutaka

    2012-01-01

    Highlights: ► Cellular senescence plays an important role in tumorigenesis and aging process. ► We demonstrated IGF-I enhanced cellular senescence in primary confluent cells. ► IGF-I enhanced cellular senescence in the ROS and p53-dependent manner. ► These results may explain the underlying mechanisms of IGF-I involvement in tumorigenesis and in regulation of aging. -- Abstract: Cellular senescence is characterized by growth arrest, enlarged and flattened cell morphology, the expression of senescence-associated β-galactosidase (SA-β-gal), and by activation of tumor suppressor networks. Insulin-like growth factor-I (IGF-I) plays a critical role in cellular growth, proliferation, tumorigenesis, and regulation of aging. In the present study, we show that IGF-I enhances cellular senescence in mouse, rat, and human primary cells in the confluent state. IGF-I induced expression of a DNA damage marker, γH2AX, the increased levels of p53 and p21 proteins, and activated SA-β-gal. In the confluent state, an altered downstream signaling of IGF-I receptor was observed. Treatment with a reactive oxygen species (ROS) scavenger, N-acetylcystein (NAC) significantly suppressed induction of these markers, indicating that ROS are involved in the induction of cellular senescence by IGF-I. In p53-null mouse embryonic fibroblasts, the IGF-I-induced augmentation of SA-β-gal and p21 was inhibited, demonstrating that p53 is required for cellular senescence induced by IGF-I. Thus, these data reveal a novel pathway whereby IGF-I enhances cellular senescence in the ROS and p53-dependent manner and may explain the underlying mechanisms of IGF-I involvement in tumorigenesis and in regulation of aging.

  17. IGF-I Bioactivity in Aging, Health and Disease

    NARCIS (Netherlands)

    M.P. Brugts (Michael)

    2010-01-01

    textabstractThe existence of insulin-like growth factors (IGFs) in blood was fi rst recognized by Wiliam D. Salmon Jr. and Wiliam H. Daughaday in 1956. Examining the role of pituitary-regulated growth-stimulating substances, these authors demonstrated that a growth hormone (GH) dependent factor

  18. Impact of IGF-I release kinetics on bone healing: a preliminary study in sheep.

    Science.gov (United States)

    Luginbuehl, Vera; Zoidis, Evangelos; Meinel, Lorenz; von Rechenberg, Brigitte; Gander, Bruno; Merkle, Hans P

    2013-09-01

    Spatiotemporal release of growth factors from a delivery device can profoundly affect the efficacy of bone growth induction. Here, we report on a delivery platform based on the encapsulation of insulin-like growth factor I (IGF-I) in different poly(D,L-lactide) (PLA) and poly(D,L-lactide-co-glycolide) (PLGA) microsphere (MS) formulations to control IGF-I release kinetics. In vitro IGF-I release profiles generally exhibited an initial burst (14-36% of total IGF-I content), which was followed by a more or less pronounced dormant phase with little release (2 to 34 days), and finally, a third phase of re-increased IGF-I release. The osteoinductive potential of these different IGF-I PL(G)A MS formulations was tested in studies using 8-mm metaphyseal drill hole bone defects in sheep. Histomorphometric analysis at 3 and 6 weeks after surgery showed that new bone formation was improved in the defects locally treated with IGF-I PL(G)A MS (n=5) as compared to defects filled with IGF-I-free PL(G)A MS (n=4). The extent of new bone formation was affected by the particular release kinetics, although a definitive relationship was not evident. Local administration of IGF-I resulted in down-regulation of inflammatory marker genes in all IGF-I treated defects. The over-expression of growth factor genes in response to IGF-I delivery was restricted to formulations that produced osteogenic responses. These experiments demonstrate the osteoinductive potential of sustained IGF-I delivery and show the importance of delivery kinetics for successful IGF-I-based therapies. Copyright © 2013 Elsevier B.V. All rights reserved.

  19. Effect of Insulin Infusion on insulin-like growth factor I (IGF-I) during Hemodialysis

    DEFF Research Database (Denmark)

    Reinhard, Mark; Frystyk, Jan; Bjerre, Mette

    2012-01-01

    Background: Hemodialysis (HD) is a catabolic procedure probably contributing to the high frequency of protein-energy wasting among patients on maintenance HD. The aim was to investigate the effect of insulin infusion on insulin-like growth factor I (IGF-I) during HD compared with a meal alone...... infusion and followed by the only meal allowed during the study. Results: Data are presented as mean±SD. From baseline to end of HD session we observed an overall increase in both serum bioactive IGF-I (from 0.83±0.27 to 1.01±0.34 µg/L, p... in the change between the groups (p=0.43). Conclusion: A meal at the beginning of a HD session leads to an increase in bioactive IGF-I thereby assumingly counteracting the catabolic effects of HD. However, according to changes in bioactive IGF-I neither glucose nor glucose-insulin infusion during HD appear...

  20. Diosgenin induces apoptosis in IGF-1-stimulated human thyrocytes through two caspase-dependent pathways

    Energy Technology Data Exchange (ETDEWEB)

    Mu, Shumin [Provincial Hospital Affiliated to Shandong University, Jinan 250021 (China); Hospital Affiliated to Shandong Traditional Chinese Medicine University, Jinan 250011 (China); Institute of Endocrinology, Shandong Academy of Clinical Medicine, Jinan 250021 (China); Tian, Xingsong; Ruan, Yongwei [Provincial Hospital Affiliated to Shandong University, Jinan 250021 (China); Liu, Yuantao [The Second Hospital of Shandong University, Jinan 250033 (China); Bian, Dezhi [Provincial Hospital Affiliated to Shandong University, Jinan 250021 (China); Jining Medical College, Jining 272013 (China); Ma, Chunyan [Provincial Hospital Affiliated to Shandong University, Jinan 250021 (China); Yu, Chunxiao [Provincial Hospital Affiliated to Shandong University, Jinan 250021 (China); Institute of Endocrinology, Shandong Academy of Clinical Medicine, Jinan 250021 (China); Feng, Mei [Provincial Hospital Affiliated to Shandong University, Jinan 250021 (China); Wang, Furong [Shandong University of Traditional Chinese Medicine, Jinan 250011 (China); Gao, Ling [Provincial Hospital Affiliated to Shandong University, Jinan 250021 (China); Institute of Endocrinology, Shandong Academy of Clinical Medicine, Jinan 250021 (China); Zhao, Jia-jun, E-mail: jjzhao@medmail.com.cn [Provincial Hospital Affiliated to Shandong University, Jinan 250021 (China); Institute of Endocrinology, Shandong Academy of Clinical Medicine, Jinan 250021 (China)

    2012-02-10

    Highlights: Black-Right-Pointing-Pointer Diosgenin induces apoptosis in IGF-1-treated thyrocytes through two caspase pathways. Black-Right-Pointing-Pointer Diosgenin inhibits FLIP and activates caspase-8 in FAS related-pathway. Black-Right-Pointing-Pointer Diosgenin increases ROS, regulates the ratio of Bax/Bcl-2 in mitochondrial pathway. -- Abstract: Insulin-like growth factor-1 (IGF-1) is a growth factor of the thyroid that has been shown in our previous study to possess proliferative and antiapoptotic effects in FRTL-5 cell lines through the upregulation of cyclin D and Fas-associated death domain-like interleukin-1-converting enzyme (FLICE)-inhibitory protein (FLIP). Diosgenin, a natural steroid sapogenin from plants, has been shown to induce apoptosis in many cell lines, with the exception of thyroid cells. In this report, we investigated the apoptotic effect and mechanism of diosgenin in IGF-1-stimulated primary human thyrocytes. Primary human thyrocytes were preincubated with or without IGF-1 for 24 h and subsequently exposed to varying concentrations of diosgenin for different times. We found that diosgenin induced apoptosis in human thyrocytes pretreated with IGF-1 in a dose-dependent manner through the activation of caspase cascades. Moreover, diosgenin inhibited FLIP and activated caspase-8 in the FAS-related apoptotic pathway. Diosgenin increased the production of ROS, regulated the balance of Bax and Bcl-2 and cleaved caspase-9 in the mitochondrial apoptotic pathway. These results indicate that diosgenin induces apoptosis in IGF-1-stimulated primary human thyrocytes through two caspase-dependent pathways.

  1. Stimulation of glucose phosphorylation by fructose in isolated rat hepatocytes.

    Science.gov (United States)

    Van Schaftingen, E; Vandercammen, A

    1989-01-15

    The phosphorylation of glucose was measured by the formation of [3H]H2O from [2-3H]glucose in suspensions of freshly isolated rat hepatocytes. Fructose (0.2 mM) stimulated 2-4-fold the rate of phosphorylation of 5 mM glucose although not of 40 mM glucose, thus increasing the apparent affinity of the glucose phosphorylating system. A half-maximal stimulatory effect was observed at about 50 microM fructose. Stimulation was maximal 5 min after addition of the ketose and was stable for at least 40 min, during which period 60% of the fructose was consumed. The effect of fructose was reversible upon removal of the ketose. Sorbitol and tagatose were as potent as fructose in stimulating the phosphorylation of 5 mM glucose. D-Glyceraldehyde also had a stimulatory effect but at tenfold higher concentrations. In contrast, dihydroxyacetone had no significant effect and glycerol inhibited the detritiation of glucose. Oleate did not affect the phosphorylation of glucose, even in the presence of fructose, although it stimulated the formation of ketone bodies severalfold, indicating that it was converted to its acyl-CoA derivative. These results allow the conclusion that fructose stimulates glucokinase in the intact hepatocyte. They also suggest that this effect is mediated through the formation of fructose 1-phosphate, which presumably interacts with a competitive inhibitor of glucokinase other than long-chain acyl-CoAs.

  2. Expression of human choline kinase in NIH 3T3 fibroblasts increases the mitogenic potential of insulin and insulin-like growth factor I.

    Science.gov (United States)

    Chung, T; Huang, J S; Mukherjee, J J; Crilly, K S; Kiss, Z

    2000-05-01

    In mammalian cells, growth factors, oncogenes, and carcinogens stimulate phosphocholine (PCho) synthesis by choline kinase (CK), suggesting that PCho may regulate cell growth. To validate the role of PCho in mitogenesis, we determined the effects of insulin, insulin-like growth factor I (IGF-I), and other growth factors on DNA synthesis in NIH 3T3 fibroblast sublines highly expressing human choline kinase (CK) without increasing phosphatidylcholine synthesis. In serum-starved CK expressor cells, insulin and IGF-I stimulated DNA synthesis, p70 S6 kinase (p70 S6K) activity, phosphatidylinositol 3-kinase (PI3K) activity, and activating phosphorylation of p42/p44 mitogen-activated protein kinases (MAPK) to greater extents than in the corresponding vector control cells. Furthermore, the CK inhibitor hemicholinium-3 (HC-3) inhibited insulin- and IGF-I-induced DNA synthesis in the CK overexpressors, but not in the vector control cells. The results indicate that high cellular levels of PCho potentiate insulin- and IGF-I-induced DNA synthesis by MAPK- and p70 S6K-regulated mechanisms.

  3. Regulation of insulin-like growth factor (IGF) I receptor expression during muscle cell differentiation. Potential autocrine role of IGF-II.

    OpenAIRE

    Rosenthal, S M; Brunetti, A; Brown, E J; Mamula, P W; Goldfine, I D

    1991-01-01

    Muscle is an important target tissue for insulin-like growth factor (IGF) action. The presence of specific, high affinity IGF receptors, as well as the expression of IGF peptides and binding proteins by muscle suggest that a significant component of IGF action in this tissue is mediated through autocrine and/or paracrine mechanisms. To explore autocrine/paracrine action of IGFs in muscle, we studied the regulation of the IGF-I receptor and the expression of IGF peptides during differentiation...

  4. Development and clinical evaluation of a novel immunoassay for the binary complex of IGF-I and IGF-binding protein-1 in human serum

    DEFF Research Database (Denmark)

    Frystyk, Jan; Højlund, Kurt; Rasmussen, Kirsten Nyborg

    2002-01-01

    Correlation studies have suggested that IGF-binding protein (IGFBP)-1 is a dynamic regulator of free IGF-I. To further study this, we developed a monoclonal immunofluorometric assay specific for the binary complex of IGF-I and IGFBP-1 in human serum. An IGFBP-1 antibody, which recognizes all...... phospho-forms of IGFBP-1, was used for coating. An europium-labeled IGF-I antibody served as tracer. Assay incubation was performed at conditions approaching those in vivo (i.e. pH 7.4, 37 C). The assay was highly specific: no signal was obtained unless both IGF-I and IGFBP-1 were present and neither...... IGFBP-2, -3, -4, nor IGF-II caused any cross-reaction. The linear standard curve covered 3 orders of magnitude, and within and in-between assay coefficients of variation were less than 5 and 15%, respectively. To study the dynamic relationship between free IGF-I and binary complex formation, seven...

  5. The essential role of IGF-I: lessons from the long-term study and treatment of children and adults with Laron syndrome.

    Science.gov (United States)

    Laron, Z

    1999-12-01

    Fifty patients with primary GH resistance (Laron syndrome) due to molecular defects of the GH receptor or post-receptor pathways were followed from infancy through adulthood. This condition leading to long-term insulin-like growth factor-I (IGF-I) deprivation caused marked growth retardation (-4 to 8 height SD), acromicia, organomicria, retarded development of the skeletal and muscular systems, a small cranium, slow motor development, and impairment of intellectual development in some of the patients. In addition, there was progressive obesity, insulin resistance, a tendency for hypoglycemia, followed later in life by hypercholesterolemia and by glucose intolerance and even diabetes. IGF-I treatment of children with Laron syndrome, by our and other groups (150-240 microg/day sc), stimulated growth (8 cm in the first year and 4-5 cm in the following years) and normalized the biochemical abnormalities. Overdosage led to adverse effects such as hypoglycemia, edema, swelling of soft tissues, and hyperandrogenism. It is concluded that primary IGF-I deprivation induces severe auxological, biochemical, and hormonal changes, the only treatment being biosynthetic IGF-I administration.

  6. Low serum levels of free and total insulin-like growth factor I (IGF-I) in patients with anorexia nervosa are not associated with increased IGF-binding protein-3 proteolysis

    DEFF Research Database (Denmark)

    Støving, R K; Flyvbjerg, A; Frystyk, J

    1999-01-01

    Patients with anorexia nervosa (AN) are GH resistant, with elevated GH levels and low serum levels of total insulin-like growth factor I (IGF-I). IGF-I action is modulated by IGF-binding proteins (IGFBPs), and a variety of catabolic states has been characterized by the presence of increased IGFBP-3...

  7. Changes in circulating level of IGF-I and IGF-binding protein-1 from the first to second trimester as predictors of preeclampsia

    DEFF Research Database (Denmark)

    Vatten, Lars J; Nilsen, Tom I L; Juul, Anders

    2008-01-01

    To assess whether circulating IGF-I and IGF-binding protein-1 (IGFBP-1) in the first and second trimester are associated with subsequent risk of preterm and term preeclampsia.......To assess whether circulating IGF-I and IGF-binding protein-1 (IGFBP-1) in the first and second trimester are associated with subsequent risk of preterm and term preeclampsia....

  8. Development and clinical evaluation of a novel immunoassay for the binary complex of IGF-I and IGF-binding protein-1 in human serum

    DEFF Research Database (Denmark)

    Frystyk, Jan; Højlund, Kurt; Rasmussen, Kirsten Nyborg

    2002-01-01

    Correlation studies have suggested that IGF-binding protein (IGFBP)-1 is a dynamic regulator of free IGF-I. To further study this, we developed a monoclonal immunofluorometric assay specific for the binary complex of IGF-I and IGFBP-1 in human serum. An IGFBP-1 antibody, which recognizes all...... phospho-forms of IGFBP-1, was used for coating. An europium-labeled IGF-I antibody served as tracer. Assay incubation was performed at conditions approaching those in vivo (i.e. pH 7.4, 37 C). The assay was highly specific: no signal was obtained unless both IGF-I and IGFBP-1 were present and neither...

  9. Conditionally immortalized human pancreatic stellate cell lines demonstrate enhanced proliferation and migration in response to IGF-I

    Energy Technology Data Exchange (ETDEWEB)

    Rosendahl, Ann H., E-mail: ann.rosendahl@med.lu.se [Lund University, Department of Clinical Sciences Lund, Division of Surgery, Lund (Sweden); Lund University and Skåne University Hospital, Department of Clinical Sciences Lund, Division of Oncology and Pathology, Lund (Sweden); Gundewar, Chinmay; Said Hilmersson, Katarzyna [Lund University, Department of Clinical Sciences Lund, Division of Surgery, Lund (Sweden); Ni, Lan; Saleem, Moin A. [University of Bristol, School of Clinical Sciences, Children' s Renal Unit and Academic Renal Unit, Bristol (United Kingdom); Andersson, Roland [Lund University, Department of Clinical Sciences Lund, Division of Surgery, Lund (Sweden)

    2015-01-15

    Pancreatic stellate cells (PSCs) play a key role in the dense desmoplastic stroma associated with pancreatic ductal adenocarcinoma. Studies on human PSCs have been minimal due to difficulty in maintaining primary PSC in culture. We have generated the first conditionally immortalized human non-tumor (NPSC) and tumor-derived (TPSC) pancreatic stellate cells via transformation with the temperature-sensitive SV40 large T antigen and human telomerase (hTERT). These cells proliferate at 33°C. After transfer to 37°C, the SV40LT is switched off and the cells regain their primary PSC phenotype and growth characteristics. NPSC contained cytoplasmic vitamin A-storing lipid droplets, while both NPSC and TPSC expressed the characteristic markers αSMA, vimentin, desmin and GFAP. Proteome array analysis revealed that of the 55 evaluated proteins, 27 (49%) were upregulated ≥3-fold in TPSC compared to NPSC, including uPA, pentraxin-3, endoglin and endothelin-1. Two insulin-like growth factor binding proteins (IGFBPs) were inversely expressed. Although discordant IGFBP-2 and IGFBP-3 levels, IGF-I was found to stimulate proliferation of both NPSC and TPSC. Both basal and IGF-I stimulated motility was significantly enhanced in TPSC compared to NPSC. In conclusion, these cells provide a unique resource that will facilitate further study of the active stroma compartment associated with pancreatic cancer. - Highlights: • Generation of human conditionally immortalized human pancreatic stellate cell lines. • Temperature-sensitive SV40LT allows switch to primary PSC phenotype characteristics. • Proteome profiling revealed distinct expression patterns between TPSC and NPSC. • Enhanced IGF-I-stimulated proliferation and motility by TPSC compared to NPSC.

  10. Expanding the mind: insulin-like growth factor I and brain development.

    Science.gov (United States)

    Joseph D'Ercole, A; Ye, Ping

    2008-12-01

    Signaling through the type 1 IGF receptor (IGF1R) after interaction with IGF-I is crucial to the normal brain development. Manipulations of the mouse genome leading to changes in the expression of IGF-I or IGF1R significantly alters brain growth, such that IGF-I overexpression leads to brain overgrowth, whereas null mutations in either IGF-I or the IGF1R result in brain growth retardation. IGF-I signaling stimulates the proliferation, survival, and differentiation of each of the major neural lineages, neurons, oligodendrocytes, and astrocytes, as well as possibly influencing neural stem cells. During embryonic life, IGF-I stimulates neuron progenitor proliferation, whereas later it promotes neuron survival, neuritic outgrowth, and synaptogenesis. IGF-I also stimulates oligodendrocyte progenitor proliferation although inhibiting apoptosis in oligodendrocyte lineage cells and stimulating myelin production. These pleiotropic IGF-I activities indicate that other factors provide instructive signals for specific cellular events and that IGF-I acts to facilitate them. Studies of the few humans with IGF-I and/or IGF1R gene mutations indicate that IGF-I serves a similar role in man.

  11. DHT and testosterone, but not DHEA or E2, differentially modulate IGF-I, IGFBP-2, and IGFBP-3 in human prostatic stromal cells.

    Science.gov (United States)

    Le, Hanh; Arnold, Julia T; McFann, Kimberly K; Blackman, Marc R

    2006-05-01

    Prostate cancer is one of the four most common cancers in the United States, affecting one of six men. Increased serum levels of androgens and IGF-I are associated with an augmented risk of prostate cancer. Dihydrotestosterone (DHT) and testosterone (T) stimulate prostate cancer cell growth, development, and function, whereas the effects of DHT and T in prostate stromal cells, and of dehydroepiandrosterone (DHEA) in prostate cancer or stromal cells, are uncertain. We investigated the actions of DHT, T, DHEA, and estradiol (E2) on insulin-like growth factor (IGF)-I, IGF-II, IGF-I receptor (R), IGF-binding protein (IGFBP)-2, IGFBP-3, and IGFBP-5 in primary cultures of human prostatic stromal cells by assessing cell proliferation, mRNA expression, and protein secretion by MTT growth assay, quantitative real-time PCR, and ELISA, respectively. DHT and T each increased IGF-I (7-fold) and decreased IGFBP-3 (2-fold) mRNA expression and protein secretion in a dose- and time-dependent manner and increased IGFBP-2 (2-fold) mRNA in a dose- and time-dependent manner. DHEA and E2 did not significantly alter these measures. Flutamide abolished the DHT-modulated increases in IGF-I and IGFBP-2, suggesting that the influences of DHT and T on these measures were androgen receptor mediated. None of the four steroids significantly affected IGF-IR, IGF-II, or IGFBP-5 mRNA levels or stromal cell proliferation. The effects of DHT on IGF-I, IGFBP-2, and IGFBP-3 were more pronounced in stromal cultures that did not express desmin. These data suggest that DHT and T promote prostate growth partly via modulation of the stromal cell IGF axis, with potential paracrine effects on prostate epithelial cells.

  12. Curcumin inhibits urothelial tumor development by suppressing IGF2 and IGF2-mediated PI3K/AKT/mTOR signaling pathway.

    Science.gov (United States)

    Tian, Binqiang; Zhao, Yingmei; Liang, Tao; Ye, Xuxiao; Li, Zuowei; Yan, Dongliang; Fu, Qiang; Li, Yonghui

    2017-08-01

    We have previously reported that curcumin inhibits urothelial tumor development in a rat bladder carcinogenesis model. In this study, we report that curcumin inhibits urothelial tumor development by suppressing IGF2 and IGF2-mediated PI3K/AKT/mTOR signaling pathway. Curcumin inhibits IGF2 expression at the transcriptional level and decreases the phosphorylation levels of IGF1R and IRS-1 in bladder cancer cells and N-methyl-N-nitrosourea (MNU)-induced urothelial tumor tissue. Ectopic expression of IGF2 and IGF1R, but not IGF1, in bladder cancer cells restored this process, suggesting that IGF2 is a target of curcumin. Moreover, introduction of constitutively active AKT1 abolished the inhibitory effect of curcumin on cell proliferation, migration, and restored the phosphorylation levels of 4E-BP1 and S6K1, suggesting that curcumin functions via suppressing IGF2-mediated AKT/mTOR signaling pathway. In summary, our results reveal that suppressing IGF2 and IGF2-mediated PI3K/AKT/mTOR signaling pathway is one of the mechanisms of action of curcumin. Our findings suggest a new therapeutic strategy against human bladder cancer caused by aberrant activation of IGF2, which are useful for translational application of curcumin.

  13. Thyroid hormone modulates insulin-like growth factor-I(IGF-I) and IGF-binding protein-3, without mediation by growth hormone, in patients with autoimmune thyroid diseases.

    Science.gov (United States)

    Inukai, T; Takanashi, K; Takebayashi, K; Fujiwara, Y; Tayama, K; Takemura, Y

    1999-10-01

    The expression and synthesis of insulin-like growth factor-1 (IGF-I) and IGF-binding protein-3 (IGFBP-3) are regulated by various hormones and nutritional conditions. We evaluated the effects of thyroid hormones on serum levels of IGF-I and IGFBP-3 levels in patients with autoimmune thyroid diseases including 54 patients with Graves' disease and 17 patients with Hashimoto's thyroiditis, and in 32 healthy age-matched control subjects. Patients were subdivided into hyperthyroid, euthyroid and hypothyroid groups that were untreated, or were treated with methylmercaptoimidazole (MMI) or L-thyroxine (L-T4). Serum levels of growth hormone (GH), IGF-I and IGFBP-3 were determined by radioimmunoassay. Serum GH levels did not differ significantly between the hyperthyroid and the age-matched euthyroid patients with Graves' disease. The serum levels of IGF-I and IGFBP-3 showed a significant positive correlation in the patients (R=0.616, Phyperthyroid patients with Graves' disease or in those with Hashimoto's thyroiditis induced by excess L-T4 administration than in control subjects. Patients with hypothyroid Graves' disease induced by the excess administration of MMI showed significantly lower IGFBP-3 levels as compared to those in healthy controls (Phormone modulates the synthesis and/or the secretion of IGF-I and IGFBP-3, and this function is not mediated by GH.

  14. Polymorphisms of genes coding for insulin-like growth factor 1 and its major binding proteins, circulating levels of IGF-I and IGFBP-3 and breast cancer risk: results from the EPIC study.

    NARCIS (Netherlands)

    Canzian, F; McKay, J D; Cleveland, R J; Dossus, Laure; Biessy, Carine; Rinaldi, Sabina; Landi, S; Boillot, C; Monnier, S; Chajès, V; Clavel-Chapelon, Françoise; Téhard, B; Chang-Claude, J; Linseisen, Jakob; Lahmann, Petra H; Pischon, Tobias; Trichopoulos, Dimitrios; Trichopoulou, Antonia; Zilis, D; Palli, Domenico; Tumino, Rosario; Vineis, Paolo; Berrino, Franco; Bueno-de-Mesquita, H Bas; Gils, C H van; Peeters, Petra H M; Pera, Guillem; Ardanaz, Eva; Chirlaque, María-Dolores; Quirós, José Ramón; Larrañaga, Nerea; Martínez-García, Carmen; Allen, Naomi E; Key, Timothy J; Bingham, Sheila A; Khaw, Kay-Tee; Slimani, N; Norat, Teresa; Riboli, Elio; Kaaks, Rudolf

    2006-01-01

    Insulin-like growth factor I (IGF-I) stimulates cell proliferation and can enhance the development of tumours in different organs. Epidemiological studies have shown that an elevated level of circulating IGF-I is associated with increased risk of breast cancer, as well as of other cancers. Most of

  15. Circulating levels of insulin-like growth factor-I (IGF-I correlate with disease status in leprosy

    Directory of Open Access Journals (Sweden)

    Rodrigues Luciana

    2011-12-01

    Full Text Available Abstract Background Caused by Mycobacterium leprae (ML, leprosy presents a strong immune-inflammatory component, whose status dictates both the clinical form of the disease and the occurrence of reactional episodes. Evidence has shown that, during the immune-inflammatory response to infection, the growth hormone/insulin-like growth factor-I (GH/IGF-I plays a prominent regulatory role. However, in leprosy, little, if anything, is known about the interaction between the immune and neuroendocrine systems. Methods In the present retrospective study, we measured the serum levels of IGF-I and IGBP-3, its major binding protein. These measurements were taken at diagnosis in nonreactional borderline tuberculoid (NR BT, borderline lepromatous (NR BL, and lepromatous (NR LL leprosy patients in addition to healthy controls (HC. LL and BL patients who developed reaction during the course of the disease were also included in the study. The serum levels of IGF-I, IGFBP-3 and tumor necrosis factor-alpha (TNF-α were evaluated at diagnosis and during development of reversal (RR or erythema nodosum leprosum (ENL reaction by the solid phase, enzyme-labeled, chemiluminescent-immunometric method. Results The circulating IGF-I/IGFBP-3 levels showed significant differences according to disease status and occurrence of reactional episodes. At the time of leprosy diagnosis, significantly lower levels of circulating IGF-I/IGFBP-3 were found in NR BL and NR LL patients in contrast to NR BT patients and HCs. However, after treatment, serum IGF-I levels in BL/LL patients returned to normal. Notably, the levels of circulating IGF-I at diagnosis were low in 75% of patients who did not undergo ENL during treatment (NR LL patients in opposition to the normal levels observed in those who suffered ENL during treatment (R LL patients. Nonetheless, during ENL episodes, the levels observed in RLL sera tended to decrease, attaining similar levels to those found in NR LL patients

  16. The role of the IGF axis in IGFBP-1 and IGF-I induced renal enlargement in Snell dwarf mice

    NARCIS (Netherlands)

    M. van Kleffens (Marjolein); D.J. Lindenbergh-Kortleve (Dicky); J.G. Koster; J.W. van Neck (Han); A. Flyvbjerg (Allan); R. Rasch; S.L.S. Drop (Stenvert); S.C. van Buul-Offers

    2001-01-01

    textabstractInsulin-like growth factor (IGF) binding protein-1 (IGFBP-1) is generally believed to inhibit IGF action in the circulation. In contrast, IGFBP-1 has been reported to interact with cell surfaces and enhance IGF-I action locally in some tissues. Renal IGFBP-1 levels are

  17. Nuclear targeting of IGF-1 receptor in orbital fibroblasts from Graves' disease: apparent role of ADAM17.

    Directory of Open Access Journals (Sweden)

    Neil Hoa

    Full Text Available Insulin-like growth factor-1 receptor (IGF-1R comprises two subunits, including a ligand binding domain on extra- cellular IGF-1Rα and a tyrosine phosphorylation site located on IGF-1Rβ. IGF-1R is over-expressed by orbital fibroblasts in the autoimmune syndrome, Graves' disease (GD. When activated by IGF-1 or GD-derived IgG (GD-IgG, these fibroblasts produce RANTES and IL-16, while those from healthy donors do not. We now report that IGF-1 and GD-IgG provoke IGF-1R accumulation in the cell nucleus of GD fibroblasts where it co-localizes with chromatin. Nuclear IGF-1R is detected with anti-IGF-1Rα-specific mAb and migrates to approximately 110 kDa, consistent with its identity as an IGF-1R fragment. Nuclear IGF-1R migrating as a 200 kDa protein and consistent with an intact receptor was undetectable when probed with either anti-IGF-1Rα or anti-IGF-1Rβ mAbs. Nuclear redistribution of IGF-1R is absent in control orbital fibroblasts. In GD fibroblasts, it can be abolished by an IGF-1R-blocking mAb, 1H7 and by physiological concentrations of glucocorticoids. When cell-surface IGF-1R is cross-linked with (125I IGF-1, (125I-IGF-1/IGF-1R complexes accumulate in the nuclei of GD fibroblasts. This requires active ADAM17, a membrane associated metalloproteinase, and the phosphorylation of IGF-1R. In contrast, virally encoded IGF-1Rα/GFP fusion protein localizes equivalently in nuclei in both control and GD fibroblasts. This result suggests that generation of IGF-1R fragments may limit the accumulation of nuclear IGF-1R. We thus identify a heretofore-unrecognized behavior of IGF-1R that appears limited to GD-derived fibroblasts. Nuclear IGF-1R may play a role in disease pathogenesis.

  18. Overexpression of IGF-I in skeletal muscle of transgenic mice does not prevent unloading-induced atrophy

    Science.gov (United States)

    Criswell, D. S.; Booth, F. W.; DeMayo, F.; Schwartz, R. J.; Gordon, S. E.; Fiorotto, M. L.

    1998-01-01

    This study examined the association between local insulin-like growth factor I (IGF-I) overexpression and atrophy in skeletal muscle. We hypothesized that endogenous skeletal muscle IGF-I mRNA expression would decrease with hindlimb unloading (HU) in mice, and that transgenic mice overexpressing human IGF-I (hIGF-I) specifically in skeletal muscle would exhibit less atrophy after HU. Male transgenic mice and nontransgenic mice from the parent strain (FVB) were divided into four groups (n = 10/group): 1) transgenic, weight-bearing (IGF-I/WB); 2) transgenic, hindlimb unloaded (IGF-I/HU); 3) nontransgenic, weight-bearing (FVB/WB); and 4) nontransgenic, hindlimb unloaded (FVB/HU). HU groups were hindlimb unloaded for 14 days. Body mass was reduced (P < 0.05) after HU in both IGF-I (-9%) and FVB mice (-13%). Contrary to our hypothesis, we found that the relative abundance of mRNA for the endogenous rodent IGF-I (rIGF-I) was unaltered by HU in the gastrocnemius (GAST) muscle of wild-type FVB mice. High-level expression of hIGF-I peptide and mRNA was confirmed in the GAST and tibialis anterior (TA) muscles of the transgenic mice. Nevertheless, masses of the GAST and TA muscles were reduced (P < 0.05) in both FVB/HU and IGF-I/HU groups compared with FVB/WB and IGF-I/WB groups, respectively, and the percent atrophy in mass of these muscles did not differ between FVB and IGF-I mice. Therefore, skeletal muscle atrophy may not be associated with a reduction of endogenous rIGF-I mRNA level in 14-day HU mice. We conclude that high local expression of hIGF-I mRNA and peptide in skeletal muscle alone cannot attenuate unloading-induced atrophy of fast-twitch muscle in mice.

  19. Favorable prognostic value of SOCS2 and IGF-I in breast cancer

    International Nuclear Information System (INIS)

    Haffner, Michael C; Petridou, Barbara; Peyrat, Jean Phillipe; Révillion, Françoise; Müller-Holzner, Elisabeth; Daxenbichler, Günter; Marth, Christian; Doppler, Wolfgang

    2007-01-01

    Suppressor of cytokine signaling (SOCS) proteins comprise a protein family, which has initially been described as STAT induced inhibitors of the Jak/Stat pathway. Recent in vivo and in vitro studies suggest that SOCS proteins are also implicated in cancer. The STAT5 induced IGF-I acts as an endocrine and para/autocrine growth and differentiation factor in mammary gland development. Whereas high levels of circulating IGF-I have been associated with increased cancer risk, the role of autocrine acting IGF-I is less clear. The present study is aimed to elucidate the clinicopathological features associated with SOCS1, SOCS2, SOCS3, CIS and IGF-I expression in breast cancer. We determined the mRNA expression levels of SOCS1, SOCS2, SOCS3, CIS and IGF-I in 89 primary breast cancers by reverse transcriptase PCR. SOCS2 protein expression was further evaluated by immuno-blot and immunohistochemistry. SOCS2 expression inversely correlated with histopathological grade and ER positive tumors exhibited higher SOCS2 levels. Patients with high SOCS2 expression lived significantly longer (108.7 vs. 77.7 months; P = 0.015) and high SOCS2 expression proved to be an independent predictor for good prognosis (HR = 0.45, 95% CI 0.23 – 0.91, P = 0.026). In analogy to SOCS2, high IGF-I expression was an independent predictor for good prognosis in the entire patient cohort. In the subgroup of patients with lymph-node negative disease, high IGF-I was a strong predictor for favorable outcome in terms of overall survival and relapse free survival (HR = 0.075, 95% CI 0.014 – 0.388, P = 0.002). This is the first report on the favorable prognostic value of high SOCS2 expression in primary mammary carcinomas. Furthermore a strong association of high IGF-I expression levels with good prognosis was observed especially in lymph-node negative patients. Our results suggest that high expression of the STAT5 target genes SOCS2 and IGF-I is a feature of differentiated and less malignant tumors

  20. AKT signaling mediates IGF-I survival actions on otic neural progenitors.

    Directory of Open Access Journals (Sweden)

    Maria R Aburto

    Full Text Available BACKGROUND: Otic neurons and sensory cells derive from common progenitors whose transition into mature cells requires the coordination of cell survival, proliferation and differentiation programmes. Neurotrophic support and survival of post-mitotic otic neurons have been intensively studied, but the bases underlying the regulation of programmed cell death in immature proliferative otic neuroblasts remains poorly understood. The protein kinase AKT acts as a node, playing a critical role in controlling cell survival and cell cycle progression. AKT is activated by trophic factors, including insulin-like growth factor I (IGF-I, through the generation of the lipidic second messenger phosphatidylinositol 3-phosphate by phosphatidylinositol 3-kinase (PI3K. Here we have investigated the role of IGF-dependent activation of the PI3K-AKT pathway in maintenance of otic neuroblasts. METHODOLOGY/PRINCIPAL FINDINGS: By using a combination of organotypic cultures of chicken (Gallus gallus otic vesicles and acoustic-vestibular ganglia, Western blotting, immunohistochemistry and in situ hybridization, we show that IGF-I-activation of AKT protects neural progenitors from programmed cell death. IGF-I maintains otic neuroblasts in an undifferentiated and proliferative state, which is characterised by the upregulation of the forkhead box M1 (FoxM1 transcription factor. By contrast, our results indicate that post-mitotic p27(Kip-positive neurons become IGF-I independent as they extend their neuronal processes. Neurons gradually reduce their expression of the Igf1r, while they increase that of the neurotrophin receptor, TrkC. CONCLUSIONS/SIGNIFICANCE: Proliferative otic neuroblasts are dependent on the activation of the PI3K-AKT pathway by IGF-I for survival during the otic neuronal progenitor phase of early inner ear development.

  1. GH/IGF-I Transgene Expression on Muscle Homeostasis

    Science.gov (United States)

    Schwartz, Robert J.

    1999-01-01

    We propose to test the hypothesis that the growth hormone/ insulin like growth factor-I axis through autocrine/paracrine mechanisms may provide long term muscle homeostasis under conditions of prolonged weightlessness. As a key alternative to hormone replacement therapy, ectopic production of hGH, growth hormone releasing hormone (GHRH), and IGF-I will be studied for its potential on muscle mass impact in transgenic mice under simulated microgravity. Expression of either hGH or IGF-I would provide a chronic source of a growth-promoting protein whose biosynthesis or secretion is shut down in space. Muscle expression of the IGF-I transgene has demonstrated about a 20% increase in hind limb muscle mass over control nontransgenic litter mates. These recent experiments, also establish the utility of hind-limb suspension in mice as a workable model to study atrophy in weight bearing muscles. Thus, transgenic mice will be used in hind-limb suspension models to determine the role of GH/IGF-I on maintenance of muscle mass and whether concentric exercises might act in synergy with hormone treatment. As a means to engineer and ensure long-term protein production that would be workable in humans, gene therapy technology will be used by to monitor muscle mass preservation during hind-limb suspension, after direct intramuscular injection of a genetically engineered muscle-specific vector expressing GHRH. Effects of this gene-based therapy will be assessed in both fast twitch (medial gastrocnemius) and slow twitch muscle (soleus). End-points include muscle size, ultrastructure, fiber type, and contractile function, in normal animals, hind limb suspension, and reambutation.

  2. Regulation of Kisspeptin Synthesis and Release in the Preoptic/Anterior Hypothalamic Region of Prepubertal Female Rats: Actions of IGF-1 and Alcohol.

    Science.gov (United States)

    Hiney, Jill K; Srivastava, Vinod K; Vaden Anderson, Danielle N; Hartzoge, Nicole L; Dees, William L

    2018-01-01

    Alcohol (ALC) causes suppressed secretion of prepubertal luteinizing hormone-releasing hormone (LHRH). Insulin-like growth factor-1 (IGF-1) and kisspeptin (Kp) are major regulators of LHRH and are critical for puberty. IGF-1 may be an upstream mediator of Kp in the preoptic area and rostral hypothalamic area (POA/RHA) of the rat brain, a region containing both Kp and LHRH neurons. We investigated the ability of IGF-1 to stimulate prepubertal Kp synthesis and release in POA/RHA, and the potential inhibitory effects of ALC. Immature female rats were administered either ALC (3 g/kg) or water via gastric gavage at 0730 hours. At 0900 hours, both groups were subdivided where half received either saline or IGF-1 into the brain third ventricle. A second dose of ALC (2 g/kg) or water was administered at 1130 hours. Rats were killed 6 hours after injection and POA/RHA region collected. IGF-1 stimulated Kp, an action blocked by ALC. Upstream to Kp, IGF-1 receptor (IGF-1R) activation, as demonstrated by the increase in insulin receptor substrate 1, resulted in activation of Akt, tuberous sclerosis 2, ras homologue enriched in brain, and mammalian target of rapamycin (mTOR). ALC blocked the central action of IGF-1 to induce their respective phosphorylation. IGF-1 specificity and ALC specificity for the Akt-activated mTOR pathway were demonstrated by the absence of effects on PRAS40. Furthermore, IGF-1 stimulated Kp release from POA/RHA incubated in vitro. IGF-1 stimulates prepubertal Kp synthesis and release following activation of a mTOR signaling pathway, and ALC blocks this pathway at the level of IGF-1R. Copyright © 2017 by the Research Society on Alcoholism.

  3. Detection of exogenous gene doping of IGF-I by a real-time quantitative PCR assay.

    Science.gov (United States)

    Zhang, Jin-Ju; Xu, Jing-Feng; Shen, Yong-Wei; Ma, Shi-Jiao; Zhang, Ting-Ting; Meng, Qing-Lin; Lan, Wen-Jun; Zhang, Chun; Liu, Xiao-Mei

    2017-07-01

    Gene doping can be easily concealed since its product is similar to endogenous protein, making its effective detection very challenging. In this study, we selected insulin-like growth factor I (IGF-I) exogenous gene for gene doping detection. First, the synthetic IGF-I gene was subcloned to recombinant adeno-associated virus (rAAV) plasmid to produce recombinant rAAV2/IGF-I-GFP vectors. Second, in an animal model, rAAV2/IGF-I-GFP vectors were injected into the thigh muscle tissue of mice, and then muscle and blood specimens were sampled at different time points for total DNA isolation. Finally, real-time quantitative PCR was employed to detect the exogenous gene doping of IGF-I. In view of the characteristics of endogenous IGF-I gene sequences, a TaqMan probe was designed at the junction of exons 2 and 3 of IGF-I gene to distinguish it from the exogenous IGF-I gene. In addition, an internal reference control plasmid and its probe were used in PCR to rule out false-positive results through comparison of their threshold cycle (Ct) values. Thus, an accurate exogenous IGF-I gene detection approach was developed in this study. © 2016 International Union of Biochemistry and Molecular Biology, Inc.

  4. Stimulation of JNK Phosphorylation by the PTTH in Prothoracic Glands of the Silkworm, Bombyx mori

    Directory of Open Access Journals (Sweden)

    Shi-Hong Gu

    2018-02-01

    Full Text Available In this study, phosphorylation of c-Jun N-terminal kinase (JNK by the prothoracicotropic hormone (PTTH was investigated in prothoracic glands (PGs of the silkworm, Bombyx mori. Results showed that JNK phosphorylation was stimulated by the PTTH in time- and dose-dependent manners. In vitro activation of JNK phosphorylation in PGs by the PTTH was also confirmed in an in vivo experiment, in which a PTTH injection greatly increased JNK phosphorylation in PGs of day-6 last instar larvae. JNK phosphorylation caused by PTTH stimulation was greatly inhibited by U73122, a potent and specific inhibitor of phospholipase C (PLC and an increase in JNK phosphorylation was also detected when PGs were treated with agents (either A23187 or thapsigargin that directly elevated the intracellular Ca2+ concentration, thereby indicating involvement of PLC and Ca2+. Pretreatment with an inhibitor (U0126 of mitogen-activated protein kinase (MAPK/extracellular signal-regulated kinase (ERK kinase (MEK and an inhibitor (LY294002 of phosphoinositide 3-kinase (PI3K failed to significantly inhibit PTTH-stimulated JNK phosphorylation, indicating that ERK and PI3K were not related to JNK. We further investigated the effect of modulation of the redox state on JNK phosphorylation. In the presence of either an antioxidant (N-acetylcysteine, NAC or diphenylene iodonium (DPI, PTTH-stimulated JNK phosphorylation was blocked. The JNK kinase inhibitor, SP600125, markedly inhibited PTTH-stimulated JNK phosphorylation and ecdysteroid synthesis. The kinase assay of JNK in PGs confirmed its stimulation by PTTH and inhibition by SP600125. Moreover, PTTH treatment did not affect JNK or Jun mRNA expressions. Based on these findings, we concluded that PTTH stimulates JNK phosphorylation in Ca2+- and PLC-dependent manners and that the redox-regulated JNK signaling pathway is involved in PTTH-stimulated ecdysteroid synthesis in B. mori PGs.

  5. Circadian variation in serum free and total insulin-like growth factor (IGF)-I and IGF-II in untreated and treated acromegaly and growth hormone deficiency

    DEFF Research Database (Denmark)

    Skjaerbaek, Christian; Frystyk, Jan; Kaal, Andreas

    2000-01-01

    to the nocturnal increase in IGF binding protein-1. In this study we have investigated the circadian variation in circulating free IGF-I and IGF-II in patients with acromegaly and patients with adult onset growth hormone deficiency. PATIENTS: Seven acromegalic patients were studied with and without treatment...... no significant circadian variations in free IGF-I or free IGF-II in either of the two occasions. In contrast, there was a significant circadian variation of total IGF-I after adjustment for changes in plasma volume in both treated and untreated acromegaly and GH deficiency in all cases with a peak between 0300 h...

  6. Differential roles of MAPK-Erk1/2 and MAPK-p38 in insulin or insulin-like growth factor-I (IGF-I) signaling pathways for progesterone production in human ovarian cells.

    Science.gov (United States)

    Seto-Young, D; Avtanski, D; Varadinova, M; Park, A; Suwandhi, P; Leiser, A; Parikh, G; Poretsky, L

    2011-06-01

    Insulin and insulin like-growth factor-I (IGF-I) participate in the regulation of ovarian steroidogenesis. In insulin resistant states ovaries remain sensitive to insulin because insulin can activate alternative signaling pathways, such as phosphatidylinositol-3-kinase (PI-3 kinase) and mitogen-activated protein-kinase (MAPK) pathways, as well as insulin receptors and type 1 IGF receptors. We investigated the roles of MAPK-Erk1/2 and MAPK-p38 in insulin and IGF-I signaling pathways for progesterone production in human ovarian cells. Human ovarian cells were cultured in tissue culture medium in the presence of varying concentrations of insulin or IGF-I, with or without PD98059, a specific MAPK-Erk1/2 inhibitor, with or without SB203580, a specific MAPK-p38 inhibitor or with or without a specific PI-3-kinase inhibitor LY294002. Progesterone concentrations were measured using radioimmunoassay. PD98059 alone stimulated progesterone production in a dose-dependent manner by up to 65% (pprogesterone production by 13-18% (pprogesterone production by 17-20% (pprogesterone production by 20-30% (pprogesterone production by 40-60% (pprogesterone synthesis while SB203580 abolished insulin-induced progesterone production. Either PD98059 or SB203580 abolished IGF-I-induced progesterone production. Both MAPK-Erk1/2 and MAPK-p38 participate in IGF-I-induced signaling pathways for progesterone production, while insulin-induced progesterone production requires MAPK-p38, but not MAPK-Erk1/2. These studies provide further evidence for divergence of insulin and IGF-I signaling pathways for human ovarian cell steroidogenesis. © Georg Thieme Verlag KG Stuttgart · New York.

  7. Effect of the association of IGF-I, IGF-II, bFGF, TGF-beta1, GM-CSF, and LIF on the development of bovine embryos produced in vitro.

    Science.gov (United States)

    Neira, J A; Tainturier, D; Peña, M A; Martal, J

    2010-03-15

    This study examined the influence of the following growth factors and cytokines on early embryonic development: insulin-like growth factors I and II (IGF-I, IGF-II), basic fibroblast growth factor (bFGF), transforming growth factor (TGF-beta), granulocyte-macrophage colony-stimulating factor (GM-CSF), and leukemia inhibitory factor (LIF). Synthetic oviduct fluid (SOF) was used as the culture medium. We studied the development of bovine embryos produced in vitro and cultured until Day 9 after fertilization. TGF-beta1, bFGF, GM-CSF, and LIF used on their own significantly improved the yield of hatched blastocysts. IGF-I, bFGF, TGF-beta1, GM-CSF, and LIF significantly accelerated embryonic development, especially the change from the expanded blastocyst to hatched blastocyst stages. Use of a combination of these growth factors and cytokines (GF-CYK) in SOF medium produced higher percentages of blastocysts and hatched blastocysts than did use of SOF alone (45% and 22% vs. 24% and 12%; PGM-CSF, produces similar results to 10% fetal calf serum for the development of in vitro-produced bovine embryos. This entirely synthetic method of embryo culture has undeniable advantages for the biosecurity of embryo transfer. Copyright 2010 Elsevier Inc. All rights reserved.

  8. Systemic administration of insulin-like growth factor I (IGF-I) causes growth of the rat prostate

    DEFF Research Database (Denmark)

    Tørring, N; Vinter-Jensen, L; Pedersen, S B

    1997-01-01

    -I after 3 days of treatment, and administration of IGF-I concomitantly with DFMO significantly inhibited ODC activity and the weight increase of the prostate. Stereological examination of the prostate in the IGF-I-treated animals showed growth of the epithelial component of the gland. Systemic treatment...

  9. Relationship between cord blood IGF-I, IGFBP-3 levels and intrauterine growth retardation (IUGR)

    International Nuclear Information System (INIS)

    Yu Suqing; Chu Kaiqiu; Chen Shengjie

    2008-01-01

    Objective: To study the cord blood insulin-like growth factor-I (IGF-I) and its binding protein-3 (IGFBP-3) levels in neonates with intrauterine growth retardation (IUGR). Methods: Cord serum IGF-I (with RIA) and IGFBP-3 (with IRMA) levels were measured in 22 neonates with IUGR and 64 neonates with appropriate gestational age (AGA). Results: Cord blood IGF-I and IGFBP-3 levels in IUGR neonates were significantly lower than those in AGA neonates (P<0.001). Among the 86 neonates studied in this article, 44 were born pre-term and 42 were born full term. From the data, we could see that the cord blood IGF-I and IGFBP-3 levels in pre-term neonates were significantly lower than those in full-term neonates (P also <0.001). IGF-I and IGFBP-3 levels were mutually positively correlated (P<0.01). Conclusion: Cord blood IGF-I and IGFBP-3 levels were useful indicator of neonates growth. (authors)

  10. Short-term strength training and the expression of myostatin and IGF-I isoforms in rat muscle and tendon

    DEFF Research Database (Denmark)

    Heinemeier, K M; Olesen, J L; Schjerling, P

    2007-01-01

    In skeletal muscle, an increased expression of insulin like growth factor-I isoforms IGF-IEa and mechano-growth factor (MGF) combined with downregulation of myostatin is thought to be essential for training-induced hypertrophy. However, the specific effects of different contraction types on regul......In skeletal muscle, an increased expression of insulin like growth factor-I isoforms IGF-IEa and mechano-growth factor (MGF) combined with downregulation of myostatin is thought to be essential for training-induced hypertrophy. However, the specific effects of different contraction types...... on regulation of these factors in muscle are still unclear, and in tendon the functions of myostatin, IGF-IEa, and MGF in relation to training are unknown. Female Sprague-Dawley rats were subjected to 4 days of concentric, eccentric, or isometric training (n = 7-9 per group) of the medial gastrocnemius......, by stimulation of the sciatic nerve during general anesthesia. mRNA levels for myostatin, IGF-IEa, and MGF in muscle and Achilles' tendon were measured by real-time RT-PCR. Muscle myostatin mRNA decreased in response to all types of training (2- to 8-fold) (P

  11. Elevated serum IGF-I, but unaltered sex steroid levels, in healthy boys with pubertal gynaecomastia

    DEFF Research Database (Denmark)

    Mieritz, Mikkel G; Sorensen, Kaspar; Aksglaede, Lise

    2014-01-01

    OBJECTIVE: Pubertal gynaecomastia is a very common condition. Although the underlying aetiology is poorly understood, it is generally accepted that excess of oestrogens and deficit of androgens are involved in the pathogenesis. Furthermore, adiposity as well as the GH/IGF-I axis may play a role....... In this study, we elucidate the association of adiposity and levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), sex hormone-binding globulin (SHBG), testosterone, oestrogen, IGF-I and IGFBP-3 with the presence of pubertal gynaecomastia in a large cohort of healthy boys. PATIENTS: A total...... of 501 healthy Danish school boys (aged 6·1-19·8 year) from the COPENHAGEN Puberty Study. MEASUREMENTS: Anthropometry and pubertal stages (PH1-6 and G1-5) were evaluated, and the presence of gynaecomastia was assessed. Body fat percentage was calculated by means of four skin folds and impedance...

  12. Favorable prognostic value of SOCS2 and IGF-I in breast cancer

    Directory of Open Access Journals (Sweden)

    Daxenbichler Günter

    2007-07-01

    Full Text Available Abstract Background Suppressor of cytokine signaling (SOCS proteins comprise a protein family, which has initially been described as STAT induced inhibitors of the Jak/Stat pathway. Recent in vivo and in vitro studies suggest that SOCS proteins are also implicated in cancer. The STAT5 induced IGF-I acts as an endocrine and para/autocrine growth and differentiation factor in mammary gland development. Whereas high levels of circulating IGF-I have been associated with increased cancer risk, the role of autocrine acting IGF-I is less clear. The present study is aimed to elucidate the clinicopathological features associated with SOCS1, SOCS2, SOCS3, CIS and IGF-I expression in breast cancer. Methods We determined the mRNA expression levels of SOCS1, SOCS2, SOCS3, CIS and IGF-I in 89 primary breast cancers by reverse transcriptase PCR. SOCS2 protein expression was further evaluated by immuno-blot and immunohistochemistry. Results SOCS2 expression inversely correlated with histopathological grade and ER positive tumors exhibited higher SOCS2 levels. Patients with high SOCS2 expression lived significantly longer (108.7 vs. 77.7 months; P = 0.015 and high SOCS2 expression proved to be an independent predictor for good prognosis (HR = 0.45, 95% CI 0.23 – 0.91, P = 0.026. In analogy to SOCS2, high IGF-I expression was an independent predictor for good prognosis in the entire patient cohort. In the subgroup of patients with lymph-node negative disease, high IGF-I was a strong predictor for favorable outcome in terms of overall survival and relapse free survival (HR = 0.075, 95% CI 0.014 – 0.388, P = 0.002. Conclusion This is the first report on the favorable prognostic value of high SOCS2 expression in primary mammary carcinomas. Furthermore a strong association of high IGF-I expression levels with good prognosis was observed especially in lymph-node negative patients. Our results suggest that high expression of the STAT5 target genes SOCS2 and IGF-I

  13. Accelerated Telomere Shortening in Acromegaly; IGF-I Induces Telomere Shortening and Cellular Senescence.

    Science.gov (United States)

    Matsumoto, Ryusaku; Fukuoka, Hidenori; Iguchi, Genzo; Odake, Yukiko; Yoshida, Kenichi; Bando, Hironori; Suda, Kentaro; Nishizawa, Hitoshi; Takahashi, Michiko; Yamada, Shozo; Ogawa, Wataru; Takahashi, Yutaka

    2015-01-01

    Patients with acromegaly exhibit reduced life expectancy and increased prevalence of age-related diseases, such as diabetes, hypertension, and cardiovascular disease. However, the underlying mechanism has not been fully elucidated. Telomere shortening is reportedly associated with reduced life expectancy and increased prevalence of these age-related diseases. We measured telomere length in patients with acromegaly using quantitative PCR method. The effect of GH and IGF-I on telomere length and cellular senescence was examined in human skin fibroblasts. Patients with acromegaly exhibited shorter telomere length than age-, sex-, smoking-, and diabetes-matched control patients with non-functioning pituitary adenoma (0.62 ± 0.23 vs. 0.75 ± 0.35, respectively, P = 0.047). In addition, telomere length in acromegaly was negatively correlated with the disease duration (R2 = 0.210, P = 0.003). In vitro analysis revealed that not GH but IGF-I induced telomere shortening in human skin fibroblasts. Furthermore, IGF-I-treated cells showed increased senescence-associated β-galactosidase activity and expression of p53 and p21 protein. IGF-I-treated cells reached the Hayflick limit earlier than GH- or vehicle-treated cells, indicating that IGF-I induces cellular senescence. Shortened telomeres in acromegaly and cellular senescence induced by IGF-I can explain, in part, the underlying mechanisms by which acromegaly exhibits an increased morbidity and mortality in association with the excess secretion of IGF-I.

  14. Changes in circulating level of IGF-I and IGF-binding protein-1 from the first to second trimester as predictors of preeclampsia

    DEFF Research Database (Denmark)

    Vatten, Lars J; Nilsen, Tom I L; Juul, Anders

    2008-01-01

    OBJECTIVE: To assess whether circulating IGF-I and IGF-binding protein-1 (IGFBP-1) in the first and second trimester are associated with subsequent risk of preterm and term preeclampsia. METHODS: Nested case-control study within a cohort of 29 948 pregnant women. Cases were women, who later...... developed preeclampsia, and controls were randomly selected women, who did not develop preeclampsia. IGF-I and IGFBP-1 were measured with ELISA in maternal blood samples that were collected in the first and second trimesters. We assessed associations of IGF-I and IGFBP-1 concentrations with later...... development of preterm (before the 37th week of gestation) and term preeclampsia. RESULTS: An increase in IGF-I from the first to second trimester was associated with higher risk of preterm preeclampsia; the odds ratio (OR) for the highest compared with lowest quartile of increase was 4.9 (95% confidence...

  15. Investigation on the role of IGF-1 signal transduction in the biological radiation responses

    Energy Technology Data Exchange (ETDEWEB)

    Jung, U Hee; Jo, Sung Kee; Park, Hae Ran; Oh, Soo Jin; Cho, Eun Hee; Eom, Hyun Soo; Ju, Eun Jin

    2009-05-15

    Effects of {gamma}-irradiation on the IGF-1 related gene expressions and activations in various cell lines - Various expression patterns of IGF-1 and IGF-1R following {gamma}-irradiation were observed according to the cell lines - The increased expressions of IGF-1 and IGF-1R were observed in Balb/3T3 and NIH/3T3 cells - Among the IGF-1 downstream signaling molecules, the phosphorylated ERK5 were not changed by {gamma}-irradiation in all three examined cell lines, whereas the phosphorylated p65 were increased by {gamma} -irradiation in all cell lines. The role of IGF-1 and p38 signaling in {gamma}-irradiated mouse embryonic fibroblast (MEF) cells - In MEF cells, IGF-1 signaling molecules were decreased and p21/phosphorylated p38 were increased by {gamma}-irradiation - The experiments with IGF-1R inhibitor (AG1024) and p38 inhibitor (SB203580) revealed that IGF-1 signaling is involved but not essential in radiation-induced cell growth arrest and senescence and that p38 MAP kinase play a important role in this cellular radiation response. The role of IGF-1 and p38 signaling in {gamma}-irradiated mouse fibroblast (NIH/3T3) cell - In NIH/3T3 cells, IGF-1 signaling molecules and p21/phosphorylated p38 were increased by {gamma} -irradiation. - However, the experiments with IGF-1R inhibitor (AG1024) and p38 inhibitor (SB203580) revealed that IGF-1 and p38 signaling do not play a crucial role in radiation-induced cell growth arrest and senescence in NIH/3T3 cells. Effects of {gamma}-irradiation on the expressions and activations on the genes related to the IGF-1 signaling in mouse tissues - In {gamma}-irradiated mice, the increased expressions of IGF-1 and IGF-1R were observed in the lung and kidney at 2 months after irradiation, and in all the tissues examined (lung, liver and kidney) at 6 months after irradiation. - In the lung of {gamma}-irradiated mice at 6 months after irradiation, the increases of IGF-1R, phosphorylated FOXO3a, p65, p38, p21 were observed. - The

  16. Investigation on the role of IGF-1 signal transduction in the biological radiation responses

    International Nuclear Information System (INIS)

    Jung, U Hee; Jo, Sung Kee; Park, Hae Ran; Oh, Soo Jin; Cho, Eun Hee; Eom, Hyun Soo; Ju, Eun Jin

    2009-05-01

    Effects of γ-irradiation on the IGF-1 related gene expressions and activations in various cell lines - Various expression patterns of IGF-1 and IGF-1R following γ-irradiation were observed according to the cell lines - The increased expressions of IGF-1 and IGF-1R were observed in Balb/3T3 and NIH/3T3 cells - Among the IGF-1 downstream signaling molecules, the phosphorylated ERK5 were not changed by γ-irradiation in all three examined cell lines, whereas the phosphorylated p65 were increased by γ -irradiation in all cell lines. The role of IGF-1 and p38 signaling in γ-irradiated mouse embryonic fibroblast (MEF) cells - In MEF cells, IGF-1 signaling molecules were decreased and p21/phosphorylated p38 were increased by γ-irradiation - The experiments with IGF-1R inhibitor (AG1024) and p38 inhibitor (SB203580) revealed that IGF-1 signaling is involved but not essential in radiation-induced cell growth arrest and senescence and that p38 MAP kinase play a important role in this cellular radiation response. The role of IGF-1 and p38 signaling in γ-irradiated mouse fibroblast (NIH/3T3) cell - In NIH/3T3 cells, IGF-1 signaling molecules and p21/phosphorylated p38 were increased by γ -irradiation. - However, the experiments with IGF-1R inhibitor (AG1024) and p38 inhibitor (SB203580) revealed that IGF-1 and p38 signaling do not play a crucial role in radiation-induced cell growth arrest and senescence in NIH/3T3 cells. Effects of γ-irradiation on the expressions and activations on the genes related to the IGF-1 signaling in mouse tissues - In γ-irradiated mice, the increased expressions of IGF-1 and IGF-1R were observed in the lung and kidney at 2 months after irradiation, and in all the tissues examined (lung, liver and kidney) at 6 months after irradiation. - In the lung of γ-irradiated mice at 6 months after irradiation, the increases of IGF-1R, phosphorylated FOXO3a, p65, p38, p21 were observed. - The patterns of altered expressions showed significant

  17. Long-term IGF-I treatment of children with Laron syndrome increases adiposity.

    Science.gov (United States)

    Laron, Zvi; Ginsberg, Shira; Lilos, Pnina; Arbiv, Mira; Vaisman, Nahum

    2006-02-01

    Laron syndrome (LS) is an autosomal recessive disease caused by deletions or mutations in the GH receptor gene leading to an inability of insulin-like growth factor I (IGF-I) generation. Among the major resulting body changes are dwarfism and obesity. The only effective treatment is daily administration of biosynthetic IGF-I. Body composition determination by DEXA (dual energy X-ray absorptiometry) of three girls with LS treated by IGF-I for 1, 3 and 11 1/2 years, respectively, revealed that concomitantly with the increase in growth there was a significant increase in body adipose tissue to double or triple the normal values. Due to the underdevelopment of the muscular and skeletal systems body mass index (BMI) did not accurately reflect the degree of obesity. In conclusion, IGF-I similar to insulin, exerts an adipogenic effect.

  18. Response to GH treatment in adult GH deficiency is predicted by gender, age, and IGF1 SDS but not by stimulated GH-peak

    DEFF Research Database (Denmark)

    Feldt-Rasmussen, Ulla; Brabant, Georg; Maiter, Dominique

    2013-01-01

    We studied whether the severity of GH deficiency (GHD) defined as i) GH-peak on stimulation tests (insulin tolerance test (ITT), arginine, and glucagon), ii) number of additional pituitary deficits, or iii) baseline IGF1 SDS could impact the response to GH treatment. We further explored whether iv...

  19. Increased IGF-IEc expression and mechano-growth factor production in intestinal muscle of fibrostenotic Crohn's disease and smooth muscle hypertrophy.

    Science.gov (United States)

    Li, Chao; Vu, Kent; Hazelgrove, Krystina; Kuemmerle, John F

    2015-12-01

    The igf1 gene is alternatively spliced as IGF-IEa and IGF-IEc variants in humans. In fibrostenotic Crohn's disease, the fibrogenic cytokine TGF-β1 induces IGF-IEa expression and IGF-I production in intestinal smooth muscle and results in muscle hyperplasia and collagen I production that contribute to stricture formation. Mechano-growth factor (MGF) derived from IGF-IEc induces skeletal and cardiac muscle hypertrophy following stress. We hypothesized that increased IGF-IEc expression and MGF production mediated smooth muscle hypertrophy also characteristic of fibrostenotic Crohn's disease. IGF-IEc transcripts and MGF protein were increased in muscle cells isolated from fibrostenotic intestine under regulation by endogenous TGF-β1. Erk5 and MEF2C were phosphorylated in vivo in fibrostenotic muscle; both were phosphorylated and colocalized to nucleus in response to synthetic MGF in vitro. Smooth muscle-specific protein expression of α-smooth muscle actin, γ-smooth muscle actin, and smoothelin was increased in affected intestine. Erk5 inhibition or MEF2C siRNA blocked smooth muscle-specific gene expression and hypertrophy induced by synthetic MGF. Conditioned media of cultured fibrostenotic muscle induced muscle hypertrophy that was inhibited by immunoneutralization of endogenous MGF or pro-IGF-IEc. The results indicate that TGF-β1-dependent IGF-IEc expression and MGF production in patients with fibrostenotic Crohn's disease regulates smooth muscle cell hypertrophy a critical factor that contributes to intestinal stricture formation. Copyright © 2015 the American Physiological Society.

  20. Low serum insulin-like growth factor-I (IGF-I) level is associated with increased risk of vascular dementia.

    Science.gov (United States)

    Quinlan, Patrick; Horvath, Alexandra; Nordlund, Arto; Wallin, Anders; Svensson, Johan

    2017-12-01

    Insulin-like growth factor-I (IGF-I) is important for the adult brain, but little is known of the role of IGF-I in Alzheimeŕs disease (AD) or vascular dementia (VaD). A prospective study of 342 patients with subjective or objective mild cognitive impairment recruited at a single memory clinic. We determined whether serum IGF-I concentrations at baseline were associated with the risk of all-cause dementia, AD, or VaD. Patients developing mixed forms of AD and VaD were defined as suffering from VaD. The statistical analyses included Cox proportional hazards regression analysis. During the follow-up (mean 3.6 years), 95 (28%) of the patients developed all-cause dementia [AD, n=37 (11%) and VaD, n=42 (12%)]. Low as well as high serum IGF-I (quartile 1 or 4 vs. quartiles 2-3) did not associate with all-cause dementia [crude hazard ratio (HR) 1.30, 95% confidence interval (CI): 0.81-2.08 and crude HR 1.05, 95% CI: 0.63-1.75, respectively] or AD (crude HR 0.79, 95% CI: 0.35-1.79 and crude HR 0.94, 95% CI: 0.43-2.06, respectively]. In contrast, low serum IGF-I concentrations were associated with increased risk of VaD (quartile 1 vs. quartiles 2-3, crude HR 2.22, 95% CI: 1.13-4.36). The latter association remained significant also after adjustment for multiple covariates. In a memory clinic population, low serum IGF-I was a risk marker for subsequent VaD whereas low IGF-I did not associate with the risk of AD. High serum IGF-I was not related to the risk of conversion to dementia. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Biochemical characterization of individual human glycosylated pro-insulin-like growth factor (IGF)-II and big-IGF-II isoforms associated with cancer.

    Science.gov (United States)

    Greenall, Sameer A; Bentley, John D; Pearce, Lesley A; Scoble, Judith A; Sparrow, Lindsay G; Bartone, Nicola A; Xiao, Xiaowen; Baxter, Robert C; Cosgrove, Leah J; Adams, Timothy E

    2013-01-04

    Insulin-like growth factor II (IGF-II) is a major embryonic growth factor belonging to the insulin-like growth factor family, which includes insulin and IGF-I. Its expression in humans is tightly controlled by maternal imprinting, a genetic restraint that is lost in many cancers, resulting in up-regulation of both mature IGF-II mRNA and protein expression. Additionally, increased expression of several longer isoforms of IGF-II, termed "pro" and "big" IGF-II, has been observed. To date, it is ambiguous as to what role these IGF-II isoforms have in initiating and sustaining tumorigenesis and whether they are bioavailable. We have expressed each individual IGF-II isoform in their proper O-glycosylated format and established that all bind to the IGF-I receptor and both insulin receptors A and B, resulting in their activation and subsequent stimulation of fibroblast proliferation. We also confirmed that all isoforms are able to be sequestered into binary complexes with several IGF-binding proteins (IGFBP-2, IGFBP-3, and IGFBP-5). In contrast to this, ternary complex formation with IGFBP-3 or IGFBP-5 and the auxillary protein, acid labile subunit, was severely diminished. Furthermore, big-IGF-II isoforms bound much more weakly to purified ectodomain of the natural IGF-II scavenging receptor, IGF-IIR. IGF-II isoforms thus possess unique biological properties that may enable them to escape normal sequestration avenues and remain bioavailable in vivo to sustain oncogenic signaling.

  2. Biochemical Characterization of Individual Human Glycosylated pro-Insulin-like Growth Factor (IGF)-II and big-IGF-II Isoforms Associated with Cancer

    Science.gov (United States)

    Greenall, Sameer A.; Bentley, John D.; Pearce, Lesley A.; Scoble, Judith A.; Sparrow, Lindsay G.; Bartone, Nicola A.; Xiao, Xiaowen; Baxter, Robert C.; Cosgrove, Leah J.; Adams, Timothy E.

    2013-01-01

    Insulin-like growth factor II (IGF-II) is a major embryonic growth factor belonging to the insulin-like growth factor family, which includes insulin and IGF-I. Its expression in humans is tightly controlled by maternal imprinting, a genetic restraint that is lost in many cancers, resulting in up-regulation of both mature IGF-II mRNA and protein expression. Additionally, increased expression of several longer isoforms of IGF-II, termed “pro” and “big” IGF-II, has been observed. To date, it is ambiguous as to what role these IGF-II isoforms have in initiating and sustaining tumorigenesis and whether they are bioavailable. We have expressed each individual IGF-II isoform in their proper O-glycosylated format and established that all bind to the IGF-I receptor and both insulin receptors A and B, resulting in their activation and subsequent stimulation of fibroblast proliferation. We also confirmed that all isoforms are able to be sequestered into binary complexes with several IGF-binding proteins (IGFBP-2, IGFBP-3, and IGFBP-5). In contrast to this, ternary complex formation with IGFBP-3 or IGFBP-5 and the auxillary protein, acid labile subunit, was severely diminished. Furthermore, big-IGF-II isoforms bound much more weakly to purified ectodomain of the natural IGF-II scavenging receptor, IGF-IIR. IGF-II isoforms thus possess unique biological properties that may enable them to escape normal sequestration avenues and remain bioavailable in vivo to sustain oncogenic signaling. PMID:23166326

  3. Maternal BMI, IGF-I Levels, and Birth Weight in African American and White Infants

    Directory of Open Access Journals (Sweden)

    Adriana C. Vidal

    2013-01-01

    Full Text Available At birth, elevated IGF-I levels have been linked to birth weight extremes; high birth weight and low birth weight are risk factors for adult-onset chronic diseases including obesity, cardiovascular disease, and type 2 diabetes. We examined associations between plasma IGF-I levels and birth weight among infants born to African American and White obese and nonobese women. Prepregnancy weight and height were assessed among 251 pregnant women and anthropometric measurements of full term infants (≥37 weeks of gestation were taken at birth. Circulating IGF-I was measured by ELISA in umbilical cord blood plasma. Linear regression models were utilized to examine associations between birth weight and high IGF-I, using the bottom two tertiles as referents. Compared with infants with lower IGF-I levels (≤3rd tertile, those with higher IGF-I levels (>3rd tertile were 130 g heavier at birth, (β-coefficient=230, se=58.0, P=0.0001, after adjusting for gender, race/ethnicity, gestational age, delivery route, maternal BMI and smoking. Stratified analyses suggested that these associations are more pronounced in infants born to African American women and women with BMI ≥30 kg/m2; the cross product term for IGF-I and maternal BMI was statistically significant (P≤0.0004. Our findings suggest that the association between IGF-I levels and birth weight depends more on maternal obesity than African American race/ethnicity.

  4. Accelerated Telomere Shortening in Acromegaly; IGF-I Induces Telomere Shortening and Cellular Senescence.

    Directory of Open Access Journals (Sweden)

    Ryusaku Matsumoto

    Full Text Available Patients with acromegaly exhibit reduced life expectancy and increased prevalence of age-related diseases, such as diabetes, hypertension, and cardiovascular disease. However, the underlying mechanism has not been fully elucidated. Telomere shortening is reportedly associated with reduced life expectancy and increased prevalence of these age-related diseases.We measured telomere length in patients with acromegaly using quantitative PCR method. The effect of GH and IGF-I on telomere length and cellular senescence was examined in human skin fibroblasts.Patients with acromegaly exhibited shorter telomere length than age-, sex-, smoking-, and diabetes-matched control patients with non-functioning pituitary adenoma (0.62 ± 0.23 vs. 0.75 ± 0.35, respectively, P = 0.047. In addition, telomere length in acromegaly was negatively correlated with the disease duration (R2 = 0.210, P = 0.003. In vitro analysis revealed that not GH but IGF-I induced telomere shortening in human skin fibroblasts. Furthermore, IGF-I-treated cells showed increased senescence-associated β-galactosidase activity and expression of p53 and p21 protein. IGF-I-treated cells reached the Hayflick limit earlier than GH- or vehicle-treated cells, indicating that IGF-I induces cellular senescence.Shortened telomeres in acromegaly and cellular senescence induced by IGF-I can explain, in part, the underlying mechanisms by which acromegaly exhibits an increased morbidity and mortality in association with the excess secretion of IGF-I.

  5. Accelerated Telomere Shortening in Acromegaly; IGF-I Induces Telomere Shortening and Cellular Senescence

    Science.gov (United States)

    Matsumoto, Ryusaku; Fukuoka, Hidenori; Iguchi, Genzo; Odake, Yukiko; Yoshida, Kenichi; Bando, Hironori; Suda, Kentaro; Nishizawa, Hitoshi; Takahashi, Michiko; Yamada, Shozo; Ogawa, Wataru; Takahashi, Yutaka

    2015-01-01

    Objective Patients with acromegaly exhibit reduced life expectancy and increased prevalence of age-related diseases, such as diabetes, hypertension, and cardiovascular disease. However, the underlying mechanism has not been fully elucidated. Telomere shortening is reportedly associated with reduced life expectancy and increased prevalence of these age-related diseases. Methods We measured telomere length in patients with acromegaly using quantitative PCR method. The effect of GH and IGF-I on telomere length and cellular senescence was examined in human skin fibroblasts. Results Patients with acromegaly exhibited shorter telomere length than age-, sex-, smoking-, and diabetes-matched control patients with non-functioning pituitary adenoma (0.62 ± 0.23 vs. 0.75 ± 0.35, respectively, P = 0.047). In addition, telomere length in acromegaly was negatively correlated with the disease duration (R 2 = 0.210, P = 0.003). In vitro analysis revealed that not GH but IGF-I induced telomere shortening in human skin fibroblasts. Furthermore, IGF-I-treated cells showed increased senescence-associated β-galactosidase activity and expression of p53 and p21 protein. IGF-I-treated cells reached the Hayflick limit earlier than GH- or vehicle-treated cells, indicating that IGF-I induces cellular senescence. Conclusion Shortened telomeres in acromegaly and cellular senescence induced by IGF-I can explain, in part, the underlying mechanisms by which acromegaly exhibits an increased morbidity and mortality in association with the excess secretion of IGF-I. PMID:26448623

  6. The effect of HMB ingestion on the IGF-I and IGF binding protein response to high intensity military training.

    Science.gov (United States)

    Redd, Michael J; Hoffman, Jay R; Gepner, Yftach; Stout, Jeffrey R; Hoffman, Mattan W; Ben-Dov, Daniel; Funk, Shany; Church, David D; Avital, Guy; Chen, Yacov; Frankel, Hagai; Ostfeld, Ishay

    2017-02-01

    Insulin-like growth factor-I (IGF-I) is a metabolic and anabolic biomarker that has been proposed to reflect physiological adaptations resulting from multistressor environments. The bioactivity of IGF-I is regulated by seven different insulin-like growth factor binding proteins (IGFBPs) which act not only as carriers of IGF-1, but also function as a modulator of IGF-I availability and activity. Supplementing with β-hydroxy-β-methylbutyrate (HMB) has been shown to enhance physiological outcomes associated with intense training, and has been reported to augment the IGF-1 response. The purpose of this study was to examine the effect of 23days of HMB supplementation on circulating levels of IGF-I and IGFBPs in combat soldiers during highly intense military training. Thirteen male soldiers from an elite infantry unit volunteered to participate in this double-blind, parallel design study. Soldiers were provided 3g·day -1 of either HMB (n=6) or placebo (PL; n=7). During the study soldiers performed advanced military training with periods of restricted sleep and severe environmental stressors. Blood samples were obtained prior to (PRE) and approximately 18h following the final supplement consumption (POST). No significant differences were observed for circulating IGF-1 concentrations between HMB and PL (p=0.568). In addition, no differences were seen between the groups for IGFBP-1 (p=1.000), IGFBP-2 (p=0.855), IGFBP-3 (p=0.520), IGFBP-4 (p=0.103), IGFBP-5 (p=0.886), or IGFBP-6 (p=0.775). A significant difference was noted between HMB (169.9±23.0ng·ml -1 ) and PL (207.2±28.0ng·ml -1 ) for IGFBP-7 at POST (p=0.042). Although the results of this study do not support the influence of HMB supplementation on circulating concentrations of IGF-1 or IGFBPs1-6 during high intensity military training, it does present initial evidence that it may lower circulating IGFBP-7 concentrations. This may provide some indication of a reduced stress response, but further investigation on

  7. Topoisomerase I tyrosine phosphorylation site and the DNA-interactive site

    International Nuclear Information System (INIS)

    Roll, D.; Durban, E.

    1986-01-01

    Phosphorylation of topoisomerase I (topo I) at serine by NII kinase is accompanied by stimulation of enzymatic activity. In contrast, phosphorylation at tyrosine by tyrosine kinase seems to inhibit enzymatic activity. This inhibition may be caused by interference of the phosphorylated tyrosine residue with the interaction of topo I with DNA. To test this, topo I was labeled with crude membrane fraction enriched for EGF-receptor kinase in presence of γ-P32-ATP and electrophoresed on SDS-polyacrylamide gels. Stained topo I bands were excised, dried, digested with trypsin and analyzed on a C18 reverse-phase HPLC column. One major peak of radioactivity eluted at fraction 23 with 20% acetonitrile. To obtain the DNA-interactive site, topo I was incubated with pBR322 DNA labeled by nick-translation followed by DNase I treatment, and electrophoresis on SDS-polyacrylamide gels. Tryptic peptides were generated and analyzed by reverse-phase HPLC. A major peak of radioactivity eluted at fraction 16-18 with 15.5-17% acetonitrile. Studies are in progress to resolve whether (a) the two peptides are different, i.e. the tyrosine-P site and DNA-tyrosine interactive site are localized at different regions of the topo I or (b) the peptide sequences are identical but the covalent attachment of deoxynucleotides altered the peptide's elution from the HPLC column

  8. A moderate elevation of circulating levels of IGF-I does not alter ErbB2 induced mammary tumorigenesis

    International Nuclear Information System (INIS)

    Dearth, Robert K; Kuiatse, Isere; Wang, Yu-Fen; Liao, Lan; Hilsenbeck, Susan G; Brown, Powel H; Xu, Jianming; Lee, Adrian V

    2011-01-01

    Epidemiological evidence suggests that moderately elevated levels of circulating insulin-like growth factor-I (IGF-I) are associated with increased risk of breast cancer in women. How circulating IGF-I may promote breast cancer incidence is unknown, however, increased IGF-I signaling is linked to trastuzumab resistance in ErbB2 positive breast cancer. Few models have directly examined the effect of moderately high levels of circulating IGF-I on breast cancer initiation and progression. The purpose of this study was to assess the ability of circulating IGF-I to independently initiate mammary tumorigenesis and/or accelerate the progression of ErbB2 mediated mammary tumor growth. We crossed heterozygous TTR-IGF-I mice with heterozygous MMTV-ErbB2 mice to generate 4 different genotypes: TTR-IGF-I/MMTV-ErbB2 (bigenic), TTR-IGF-I only, MMTV-ErbB2 only, and wild type (wt). Virgin females were palpated twice a week and harvested when tumors reached 1000 mm 3 . For study of normal development, blood and tissue were harvested at 4, 6 and 9 weeks of age in TTR-IGF-I and wt mice. TTR-IGF-I and TTR-IGF-I/ErbB2 bigenic mice showed a moderate 35% increase in circulating total IGF-I compared to ErbB2 and wt control mice. Elevation of circulating IGF-I had no effect upon pubertal mammary gland development. The transgenic increase in IGF-I alone wasn't sufficient to initiate mammary tumorigenesis. Elevated circulating IGF-I had no effect upon ErbB2-induced mammary tumorigenesis or metastasis, with median time to tumor formation being 30 wks and 33 wks in TTR-IGF-I/ErbB2 bigenic and ErbB2 mice respectively (p = 0.65). Levels of IGF-I in lysates from ErbB2/TTR-IGF-I tumors compared to ErbB2 was elevated in a similar manner to the circulating IGF-I, however, there was no effect on the rate of tumor growth (p = 0.23). There were no morphological differences in tumor type (solid adenocarcinomas) between bigenic and ErbB2 mammary glands. Using the first transgenic animal model to

  9. Genetic Mutations, Birth Lengths, Weights and Head Circumferences of Children with IGF-I Receptor Defects. Comparison with other Congenital Defects in the GH/IGF-I axis.

    Science.gov (United States)

    Essakow, Jenna Lee; Lauterpacht, Aharon; Lilos, Pearl; Kauli, Rivka; Laron, Zvi

    2016-09-01

    In recent years more and more genetic defects along the GHRH-GH-IGF-I axis have been reported. Mutations of the IGF-I receptor (R) are a rare abnormality of whom only the heterozygote progenies survive. To summarize, from the literature, data on birth length, weight and head circumference of neonates with IGF-I-R mutations, and to correlate the data with that of other types of mutations in the GH/IGF-I axis. Sixty seven neonates from 24 published articles were included and forty seven different mutations of the IGF-I (R) located on chromosome 15 have been identified. Mean (±SD) birth length (BL), available for 26, (10 M, 16F) neonates with a gestational age of 34-41weeks, was 44.2±4cm; one was premature (30cm at 31 weeks). There was a significant correlation between birth length and gestational age (GA) r=0.71 (p>.001). Mean birth weight (BW) of 41 neonates (18M, 23F) was 2388±743gr. Two premature neonates weighed 650gr and 950gr respectively. The BW correlated significantly with gestational age, (males: r=0.68; p=0.007, females: r=0.49; p=0.024). The BMI of 25 neonates ranged from 6 to 13. In 22 records marked microcephaly was ascertained or stated. Nine of 16 mothers were short (133 -148cm), m±SD = 150.5±7.3cm. Copyright© of YS Medical Media ltd.

  10. Ligand binding affinity at the insulin receptor isoform A (IR-A and subsequent IR-A tyrosine phosphorylation kinetics are important determinants of mitogenic biological outcomes.

    Directory of Open Access Journals (Sweden)

    Harinda eRajapaksha

    2015-07-01

    Full Text Available The insulin receptor (IR is a tyrosine kinase receptor that can mediate both metabolic and mitogenic biological actions. The IR isoform-A (IR-A arises from alternative splicing of exon 11 and has different ligand binding and signalling properties compared to the IR isoform-B. The IR-A not only binds insulin but also insulin-like growth factor-II (IGF-II with high affinity. IGF-II acting through the IR-A promotes cancer cell proliferation, survival and migration by activating some unique signalling molecules compared to those activated by insulin. This observation led us to investigate whether the different IR-A signalling outcomes in response to IGF-II and insulin could be attributed to phosphorylation of a different subset of IR-A tyrosine residues or to the phosphorylation kinetics. We correlated IR-A phosphorylation to activation of molecules involved in mitogenic and metabolic signalling (MAPK and Akt and receptor internalisation rates (related to mitogenic signalling. We also extended this study to incorporate two ligands that are known to promote predominantly mitogenic ([His4, Tyr15, Thr49, Ile51] IGF-I, qIGF-I or metabolic (S597 peptide biological actions, to see if common mechanisms can be used to define mitogenic or metabolic signalling through the IR-A. The 3-fold lower mitogenic action of IGF-II compared to insulin was associated with a decreased potency in activation of Y960, Y1146, Y1150, Y1151, Y1316 and Y1322, in MAPK phosphorylation and in IR-A internalization. With the poorly mitogenic S597 peptide it was a decreased rate of tyrosine phosphorylation rather than potency that was associated with a low mitogenic potential. We conclude that both decreased affinity of IR-A binding and the kinetics of IR-A phosphorylation can independently lead to a lower mitogenic activity. None of the studied parameters could account for the lower metabolic activity of qIGF-I.

  11. ERK phosphorylation is predictive of resistance to IGF-1R inhibition in small cell lung cancer.

    Science.gov (United States)

    Zinn, Rebekah L; Gardner, Eric E; Marchionni, Luigi; Murphy, Sara C; Dobromilskaya, Irina; Hann, Christine L; Rudin, Charles M

    2013-06-01

    New therapies are critically needed to improve the outcome for patients with small cell lung cancer (SCLC). Insulin-like growth factor 1 receptor (IGF-1R) inhibition is a potential treatment strategy for SCLC: the IGF-1R pathway is commonly upregulated in SCLC and has been associated with inhibition of apoptosis and stimulation of proliferation through downstream signaling pathways, including phosphatidylinositol-3-kinase-Akt and mitogen-activated protein kinase. To evaluate potential determinants of response to IGF-1R inhibition, we assessed the relative sensitivity of 19 SCLC cell lines to OSI-906, a small molecule inhibitor of IGF-1R, and the closely related insulin receptor. Approximately one third of these cell lines were sensitive to OSI-906, with an IC50 OSI-906. Interestingly, OSI-906 sensitive lines expressed significantly lower levels of baseline phospho-ERK relative to resistant lines (P = 0.006). OSI-906 treatment resulted in dose-dependent inhibition of phospho-IGF-1R and phospho-Akt in both sensitive and resistant cell lines, but induced apoptosis and cell-cycle arrest only in sensitive lines. We tested the in vivo efficacy of OSI-906 using an NCI-H187 xenograft model and two SCLC patient xenografts in mice. OSI-906 treatment resulted in 50% tumor growth inhibition in NCI-H187 and 30% inhibition in the primary patient xenograft models compared with mock-treated animals. Taken together our data support IGF-1R inhibition as a viable treatment strategy for a defined subset of SCLC and suggest that low pretreatment levels of phospho-ERK may be indicative of sensitivity to this therapeutic approach. ©2013 AACR

  12. Diabetic retinopathy in two patients with congenital IGF-I deficiency (Laron syndrome).

    Science.gov (United States)

    Laron, Zvi; Weinberger, Dov

    2004-07-01

    Animal and clinical studies have shown that excessive amounts of growth hormone or insulin-like growth factor-I (IGF-I) promote the development of diabetes and diabetic retinopathy. Forthwith, we present two patients with congenital IGF-I deficiency who developed type II diabetes and subsequently retinopathy. Eighteen adult patients with classical Laron syndrome (8 males, 10 females, aged 20-62 years) were followed by us since childhood or underwent fundus photography with a Nikon NF 505 instrument. Three had been treated in childhood with IGF-I, the rest were never treated, including the two patients reported. Two never-treated patients were diagnosed with type II diabetes (DM) at ages 39 and 41 respectively. There was no diabetes in the families. Oral treatment was followed by insulin injections. Metabolic control was not optimal and one patient developed proliferative diabetic retinopathy, necessitating laser surgery. He also has nephropathy and severe neuropathy. The other patient has background diabetic retinopathy and has developed, progressively, exudates, microaneurisms, hemorrhages and clinically significant macular edema. He also has subacute ischemic heart disease. Our findings show that congenital IGF-I deficiency, similar to excess, causes vascular complications of DM, denoting also that vascular endothelial growth factor can induce neovascularization in the presence of congenital IGF-I deficiency.

  13. Free and total insulin-like growth factor I (IGF-I), IGF-binding protein-1 (IGFBP-1), and IGFBP-3 and their relationships to the presence of diabetic retinopathy and glomerular hyperfiltration in insulin-dependent diabetes mellitus

    NARCIS (Netherlands)

    J.A.M.J.L. Janssen (Joseph); M.L. Jacobs (Marloes); F.H.M. Derkx (Frans); R.F.A. Weber (Robert); A-J. van der Lely (Aart-Jan); S.W.J. Lamberts (Steven)

    1997-01-01

    textabstractThe existing literature on serum insulin-like growth factor I (IGF-I) levels in insulin-dependent diabetes mellitus (IDDM) is conflicting. Free IGF-I may have greater physiological and clinical relevance than total IGF-I. Recently, a validated method has

  14. Serum insulin-like growth factor 1(IGF-I) and prostatic cancer risk a retrospective study

    International Nuclear Information System (INIS)

    Li Liren; Liu Jiumin; Lu Bailing

    2001-01-01

    Objective: To investigate the relationship between serum IGF-I levels and prostatic cancer. Methods: Serum IGF-I levels were determined by immunoradiometric assay (IRMA) in 30 cases of prostatic cancer, 30 cases of benign prostatic hyperplasia (BPH) and 30 healthy subjects as controls. Results: The mean levels of serum IGF-I in prostatic cancer (148 +- 49.6 μg/L) were significantly higher than those in BPH (91.0 +- 32.8 μg/L) and healthy subjects (105 +- 25.6 μg/L) (P 0.05). The IGF-I levels were not relates to BHP, but increased values of IGF-I were associated with increased risk of prostatic cancer. The odds ratio was 11.23 for patients of prostatic cancer compared with healthy subjects, (95 percent confidence interval 3.09 - 40.7). Conclusion: This finding suggests that high IGF-I may be associated with increase risk of prostate cancer in human

  15. Clinical significance of changes of serum expression of IGF-I in patients with astrocytoma

    International Nuclear Information System (INIS)

    Liu Jianbo; Ding Dongmei; Yang Fubing

    2005-01-01

    Objective: To investigate the serum expression of IGF-I in patients with astrocytoma of different degrees of malignancy as well as the changes of levels after operative removal of the tumor. Methods: Serum IGF-I contents were measured with IRMA in 16 patients with Grade I-II astrocytoma and 14 patients with Grade III-IV astrocytoma both before and after operation as well as in 30 controls. Results: The serum contents of IGF-I in both groups of patients were significantly higher than those in controls (P<0.05). The levels in Grade III-IV patients were significantly higher than those in Grade I-II patients (P < 0.05 ). After operation, the levels dropped significantly (vs before operation, P<0.05). Conclusion: The serum contents of IGF - I in patients with astrocytoma were positively correlated with the degree of malignancy. Post-operative decrease of IGF-I contents was related to the decrease of tumor burden. (authors)

  16. Systemic administration of IGF-I enhances healing in collagenous extracellular matrices: evaluation of loaded and unloaded ligaments

    Science.gov (United States)

    Provenzano, Paolo P; Alejandro-Osorio, Adriana L; Grorud, Kelley W; Martinez, Daniel A; Vailas, Arthur C; Grindeland, Richard E; Vanderby, Ray

    2007-01-01

    Background Insulin-like growth factor-I (IGF-I) plays a crucial role in wound healing and tissue repair. We tested the hypotheses that systemic administration of IGF-I, or growth hormone (GH), or both (GH+IGF-I) would improve healing in collagenous connective tissue, such as ligament. These hypotheses were examined in rats that were allowed unrestricted activity after injury and in animals that were subjected to hindlimb disuse. Male rats were assigned to three groups: ambulatory sham-control, ambulatory-healing, and hindlimb unloaded-healing. Ambulatory and hindlimb unloaded animals underwent surgical disruption of their knee medial collateral ligaments (MCLs), while sham surgeries were performed on control animals. Healing animals subcutaneously received systemic doses of either saline, GH, IGF-I, or GH+IGF-I. After 3 weeks, mechanical properties, cell and matrix morphology, and biochemical composition were examined in control and healing ligaments. Results Tissues from ambulatory animals receiving only saline had significantly greater strength than tissue from saline receiving hindlimb unloaded animals. Addition of IGF-I significantly improved maximum force and ultimate stress in tissues from both ambulatory and hindlimb unloaded animals with significant increases in matrix organization and type-I collagen expression. Addition of GH alone did not have a significant effect on either group, while addition of GH+IGF-I significantly improved force, stress, and modulus values in MCLs from hindlimb unloaded animals. Force, stress, and modulus values in tissues from hindlimb unloaded animals receiving IGF-I or GH+IGF-I exceeded (or were equivalent to) values in tissues from ambulatory animals receiving only saline with greatly improved structural organization and significantly increased type-I collagen expression. Furthermore, levels of IGF-receptor were significantly increased in tissues from hindlimb unloaded animals treated with IGF-I. Conclusion These results

  17. Systemic administration of IGF-I enhances healing in collagenous extracellular matrices: evaluation of loaded and unloaded ligaments

    Directory of Open Access Journals (Sweden)

    Martinez Daniel A

    2007-03-01

    Full Text Available Abstract Background Insulin-like growth factor-I (IGF-I plays a crucial role in wound healing and tissue repair. We tested the hypotheses that systemic administration of IGF-I, or growth hormone (GH, or both (GH+IGF-I would improve healing in collagenous connective tissue, such as ligament. These hypotheses were examined in rats that were allowed unrestricted activity after injury and in animals that were subjected to hindlimb disuse. Male rats were assigned to three groups: ambulatory sham-control, ambulatory-healing, and hindlimb unloaded-healing. Ambulatory and hindlimb unloaded animals underwent surgical disruption of their knee medial collateral ligaments (MCLs, while sham surgeries were performed on control animals. Healing animals subcutaneously received systemic doses of either saline, GH, IGF-I, or GH+IGF-I. After 3 weeks, mechanical properties, cell and matrix morphology, and biochemical composition were examined in control and healing ligaments. Results Tissues from ambulatory animals receiving only saline had significantly greater strength than tissue from saline receiving hindlimb unloaded animals. Addition of IGF-I significantly improved maximum force and ultimate stress in tissues from both ambulatory and hindlimb unloaded animals with significant increases in matrix organization and type-I collagen expression. Addition of GH alone did not have a significant effect on either group, while addition of GH+IGF-I significantly improved force, stress, and modulus values in MCLs from hindlimb unloaded animals. Force, stress, and modulus values in tissues from hindlimb unloaded animals receiving IGF-I or GH+IGF-I exceeded (or were equivalent to values in tissues from ambulatory animals receiving only saline with greatly improved structural organization and significantly increased type-I collagen expression. Furthermore, levels of IGF-receptor were significantly increased in tissues from hindlimb unloaded animals treated with IGF-I

  18. Is further evaluation for growth hormone (GH) deficiency necessary in fibromyalgia patients with low serum insulin-like growth factor (IGF)-I levels?

    Science.gov (United States)

    Yuen, Kevin C J; Bennett, Robert M; Hryciw, Cheryl A; Cook, Marie B; Rhoads, Sharon A; Cook, David M

    2007-02-01

    Fibromyalgia (FM) is characterized by diffuse pain, fatigue, and sleep disturbances; symptoms that resemble the adult growth hormone (GH) deficiency syndrome. Many FM patients have low serum GH levels, with a hypothesized aetiology of dysregulated GH/insulin-like growth factor (IGF)-I axis. The aim of this study was to assess the GH reserve in FM patients with low serum IGF-I levels using the GH-releasing hormone (GHRH)-arginine test. We retrospectively reviewed the GHRH-arginine data of 77 FM patients with low serum IGF-I levels referred to our tertiary unit over a 4-year period. Of the 77 FM patients, 13 patients (17%) failed the GHRH-arginine test. Further evaluation with pituitary imaging revealed normal pituitary glands (n=7), coincident microadenomas (n=4), empty sella (n=1) and pituitary cyst (n=1), and relevant medical histories such as previous head injury (n=4), Sheehan's syndrome (n=1), and whiplash injury (n=1). In contrast, the remaining 64 patients (83%) that responded to the GHRH-arginine test demonstrated higher peak GH levels compared to age and BMI-matched controls (n=24). Our data shows that a subpopulation of FM patients with low serum IGF-I levels will fail the GHRH-arginine test. We, thus, recommend that the GH reserve of these patients should be evaluated further, as GH replacement may potentially improve the symptomatology of those with true GH deficiency. Additionally, the increased GH response rates to GHRH-arginine stimulation in the majority of FM patients with low serum IGF-I levels further supports the hypothesis of a dysregulated GH/IGF-I axis in the pathophysiology of FM.

  19. Polymorphism of Insulin-like growth factor-I (IGF-I gene and their effect on growth traits in Indonesia native chicken

    Directory of Open Access Journals (Sweden)

    M.A Mu'in

    2009-12-01

    Full Text Available The research was aimed is to detect Insulin-like growth factor-I (IGF-I gene polymorphism and their effect on growth traits in Indonesia natives chicken. Seventy two Indonesian native chicken are going to be used in this research. The polymorphism of IGF-I gene was detected by PCR-RFLP/Pst-I. Four growth traits (body weight at 1, 2, 3, and 4 months were recorded for analyzing the association between IGF-I gene polymorphism and growth performance.The results showed that allele A (621 bp and allele B (364 and 257 bp were found in this research. It was found that Indonesian native chicken carried high frequencies of allele A (0.82, and frequencies of IGF-I genotypes (AA, AB, BB were 68.0, 27.8, and 4,2%, respectively. When compared to the IGF-I genotypes, the BB genotype had the highest body weight at 1, 2, 3, and 4 month (P<0.05. The results showed that the B allele was positive of associated to a higher growth rate. Therefore, these results suggest that there is a possibility of IGF-I genotypes acting as a molecular marker for growth rate of Indonesia native.

  20. Free and total insulin-like growth factor I (IGF-I), IGF-binding protein-1 (IGFBP-1), and IGFBP-3 and their relationships to the presence of diabetic retinopathy and glomerular hyperfiltration in insulin-dependent diabetes mellitus

    NARCIS (Netherlands)

    J.A.M.J.L. Janssen (Joseph); M.L. Jacobs (Marloes); F.H.M. Derkx (Frans); R.F.A. Weber (Rob); A-J. van der Lely (Aart-Jan); S.W.J. Lamberts (Steven)

    1997-01-01

    textabstractThe existing literature on serum insulin-like growth factor I (IGF-I) levels in insulin-dependent diabetes mellitus (IDDM) is conflicting. Free IGF-I may have greater physiological and clinical relevance than total IGF- I. Recently, a validated method has been developed to measure free

  1. IGF-IR internalizes with Caveolin-1 and PTRF/Cavin in HaCat cells.

    Directory of Open Access Journals (Sweden)

    Barbara Salani

    Full Text Available BACKGROUND: Insulin-like growth factor-I receptor (IGF-IR is a tyrosine kinase receptor (RTK associated with caveolae, invaginations of the plasma membrane that regulate vesicular transport, endocytosis and intracellular signaling. IGF-IR internalization represents a key mechanism of down-modulation of receptors number on plasma membrane. IGF-IR interacts directly with Caveolin-1 (Cav-1, the most relevant protein of caveolae. Recently it has been demonstrated that the Polymerase I and Transcript Release Factor I (PTRF/Cavin is required for caveolae biogenesis and function. The role of Cav-1 and PTRF/Cavin in IGF-IR internalization is still to be clarified. METHODOLOGY/PRINCIPAL FINDINGS: We have investigated the interaction of IGF-IR with Cav-1 and PTRF/Cavin in the presence of IGF1in human Hacat cells. We show that IGF-IR internalization triggers Cav-1 and PTRF/Cavin translocation from plasma membrane to cytosol and increases IGF-IR interaction with these proteins. In fact, Cav-1 and PTRF/Cavin co-immunoprecipitate with IGF-IR during receptor internalization. We found a different time course of co-immunoprecipitation between IGF-IR and Cav-1 compared to IGF-IR and PTRF/Cavin. Cav-1 and PTRF/Cavin silencing by siRNA differently affect surface IGF-IR levels following IGF1 treatment: Cav-1 and PTRF/Cavin silencing significantly affect IGF-IR rate of internalization, while PTRF/Cavin silencing also decreases IGF-IR plasma membrane recovery. Since Cav-1 phosphorylation could have a role in IGF-IR internalization, the mutant Cav-1Y14F lacking Tyr14 was transfected. Cav-1Y14F transfected cells showed a reduced internalization of IGF-IR compared with cells expressing wild type Cav-1. Receptor internalization was not impaired by Clathrin silencing. These findings support a critical role of caveolae in IGF-IR intracellular traveling. CONCLUSIONS/SIGNIFICANCE: These data indicate that Caveolae play a role in IGF-IR internalization. Based on these findings

  2. IGF-I Gene Therapy in Aging Rats Modulates Hippocampal Genes Relevant to Memory Function.

    Science.gov (United States)

    Pardo, Joaquín; Abba, Martin C; Lacunza, Ezequiel; Ogundele, Olalekan M; Paiva, Isabel; Morel, Gustavo R; Outeiro, Tiago F; Goya, Rodolfo G

    2018-03-14

    In rats, learning and memory performance decline during normal aging, which makes this rodent species a suitable model to evaluate therapeutic strategies. In aging rats, insulin-like growth factor-I (IGF-I), is known to significantly improve spatial memory accuracy as compared to control counterparts. A constellation of gene expression changes underlie the hippocampal phenotype of aging but no studies on the effects of IGF-I on the hippocampal transcriptome of old rodents have been documented. Here, we assessed the effects of IGF-I gene therapy on spatial memory performance in old female rats and compared them with changes in the hippocampal transcriptome. In the Barnes maze test, experimental rats showed a significantly higher exploratory frequency of the goal hole than controls. Hippocampal RNA-sequencing showed that 219 genes are differentially expressed in 28-month-old rats intracerebroventricularly injected with an adenovector expressing rat IGF-I as compared with placebo adenovector-injected counterparts. From the differentially expressed genes, 81 were down and 138 upregulated. From those genes, a list of functionally relevant genes, concerning hippocampal IGF-I expression, synaptic plasticity as well as neuronal function was identified. Our results provide an initial glimpse at the molecular mechanisms underlying the neuroprotective actions of IGF-I in the aging brain.

  3. Role of IGF-1R in ameliorating apoptosis of GNE deficient cells.

    Science.gov (United States)

    Singh, Reema; Chaudhary, Priyanka; Arya, Ranjana

    2018-05-09

    Sialic acids (SAs) are nine carbon acidic amino sugars, found at the outermost termini of glycoconjugates performing various physiological and pathological functions. SA synthesis is regulated by UDP-GlcNAc 2-epimerase/ManNAc kinase (GNE) that catalyzes rate limiting steps. Mutations in GNE result in rare genetic disorders, GNE myopathy and Sialuria. Recent studies indicate an alternate role of GNE in cell apoptosis and adhesion, besides SA biosynthesis. In the present study, using a HEK cell-based model for GNE myopathy, the role of Insulin-like Growth Factor Receptor (IGF-1R) as cell survival receptor protein was studied to counter the apoptotic effect of non-functional GNE. In the absence of functional GNE, IGF-1R was hyposialylated and transduced a downstream signal upon IGF-1 (IGF-1R ligand) treatment. IGF-1 induced activation of IGF-1R led to AKT (Protein Kinase B) phosphorylation that may phosphorylate BAD (BCL2 Associated Death Promoter) and its dissociation from BCL2 to prevent apoptosis. However, reduced ERK (Extracellular signal-regulated kinases) phosphorylation in GNE deficient cells after IGF-1 treatment suggests downregulation of the ERK pathway. A balance between the ERK and AKT pathways may determine the cell fate towards survival or apoptosis. Our study suggests that IGF-1R activation may rescue apoptotic cell death of GNE deficient cell lines and has potential as therapeutic target.

  4. IGF-I and IGFBP-3 levels and their correlations with ...

    African Journals Online (AJOL)

    Background: Colorectal cancer is one of the most frequently seen cancers worldwide. Currently, CEA is the most commonly used tumor marker in colorectal cancer. The changes in IGF/IGFBP equilibrium is also known to cause carcinogenesis. In this study, we aimed to monitor IGF-I/IGFBP-3 levels, the changes in ...

  5. SUMO-modified insulin-like growth factor 1 receptor (IGF-1R) increases cell cycle progression and cell proliferation.

    Science.gov (United States)

    Lin, Yingbo; Liu, Hongyu; Waraky, Ahmed; Haglund, Felix; Agarwal, Prasoon; Jernberg-Wiklund, Helena; Warsito, Dudi; Larsson, Olle

    2017-10-01

    Increasing number of studies have shown nuclear localization of the insulin-like growth factor 1 receptor (nIGF-1R) in tumor cells and its links to adverse clinical outcome in various cancers. Any obvious cell physiological roles of nIGF-1R have, however, still not been disclosed. Previously, we reported that IGF-1R translocates to cell nucleus and modulates gene expression by binding to enhancers, provided that the receptor is SUMOylated. In this study, we constructed stable transfectants of wild type IGF1R (WT) and triple-SUMO-site-mutated IGF1R (TSM) using igf1r knockout mouse fibroblasts (R-). Cell clones (R-WT and R-TSM) expressing equal amounts of IGF-1R were selected for experiments. Phosphorylation of IGF-1R, Akt, and Erk upon IGF-1 stimulation was equal in R-WT and R-TSM. WT was confirmed to enter nuclei. TSM did also undergo nuclear translocation, although to a lesser extent. This may be explained by that TSM heterodimerizes with insulin receptor, which is known to translocate to cell nuclei. R-WT proliferated substantially faster than R-TSM, which did not differ significantly from the empty vector control. Upon IGF-1 stimulation G1-S-phase progression of R-WT increased from 12 to 38%, compared to 13 to 20% of R-TSM. The G1-S progression of R-WT correlated with increased expression of cyclin D1, A, and CDK2, as well as downregulation of p27. This suggests that SUMO-IGF-1R affects upstream mechanisms that control and coordinate expression of cell cycle regulators. Further studies to identify such SUMO-IGF-1R dependent mechanisms seem important. © 2017 The Authors. Journal of Cellular Physiology Published by Wiley Periodicals Inc.

  6. IGF-I and IGFBP-3 polymorphisms in relation to circulating levels among African American and Caucasian women

    Science.gov (United States)

    D’Aloisio, Aimee A.; Schroeder, Jane C.; North, Kari E.; Poole, Charles; West, Suzanne L.; Travlos, Gregory S.; Baird, Donna D.

    2010-01-01

    Circulating insulin-like growth factor-one (IGF-I) and IGF binding protein-3 (IGFBP-3) levels have been associated with common diseases. Although family-based studies suggest that genetic variation contributes to circulating IGF-I and IGFBP-3 levels, analyses of associations with multiple IGF-I and IGFBP-3 single nucleotide polymorphisms (SNPs) have been limited, especially among African Americans. We evaluated 30 IGF-I and 15 IGFBP-3 SNPs and estimated diplotypes in association with plasma IGF-I and IGFBP-3 among 984 premenopausal African American and Caucasian women. In both races, IGFBP-3 rs2854746 (Ala32Gly) was positively associated with plasma IGFBP-3 (CC versus GG mean difference among Caucasians = 631 ng/ml, 95% confidence interval: 398, 864; African Americans = 897 ng/ml, 95% confidence interval: 656, 1138), and IGFBP-3 diplotypes with the rs2854746 GG genotype had lower mean IGFBP-3 levels than referent diplotypes with the CG genotype, while IGFBP-3 diplotypes with the CC genotype had higher mean IGFBP-3 levels. IGFBP-3 rs2854744 (−202 A/C) was in strong linkage disequilibrium with rs2854746 in Caucasians only, but was associated with plasma IGFBP-3 in both races. Eight additional IGFBP-3 SNPs were associated with 5% or greater differences in mean IGFBP-3 levels, with generally consistent associations between races. Twelve IGF-I SNPs were associated with 10% or greater differences in mean IGF-I levels, but associations were generally discordant between races. Diplotype associations with plasma IGF-I did not parallel IGF-I SNP associations. Our study supports that common IGFBP-3 SNPs, especially rs2854746, influence plasma IGFBP-3 levels among African Americans and Caucasians, but provides less evidence that IGF-I SNPs affect plasma IGF-I levels. PMID:19240240

  7. IGFBP-1 and IGF-I as markers for advanced fibrosis in NAFLD - a pilot study.

    Science.gov (United States)

    Hagström, Hannes; Stål, Per; Hultcrantz, Rolf; Brismar, Kerstin; Ansurudeen, Ishrath

    2017-12-01

    Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease globally. Advanced fibrosis (stage 3-4) is the most robust marker for future mortality, but diagnosis requires liver biopsy. Current non-invasive scoring systems aimed to identify advanced fibrosis are imperfect. Insulin-like growth factor I (IGF-I) and its binding protein IGFBP-1 are liver derived proteins, that are involved in various liver disorders. The aim of this study was to examine the possible association between advanced fibrosis and IGF-I and IGFBP-1 in NAFLD. Fasting blood samples were obtained from 52 patients diagnosed with NAFLD by liver biopsy. Total IGF-I and IGFBP-1 concentrations were determined in serum by in-house radio-immuno-assays. IGF-I levels were age-standardized (IGF-SD). A logistic regression model was used to investigate the association of IGF-SD and IGFBP-1 with advanced fibrosis (stage 3-4). Patients with advanced fibrosis (stage 3-4 vs. 0-2) had lower IGF-SD (-1.17 vs. 0.11, p = .01) and higher mean levels of IGFBP-1 (29.9 vs. 18.8 µg/l, p = .02). IGFBP-1 was associated with presence of advanced fibrosis (OR 1.04 per unit increase, 95%CI 1.0-1.07, p = .05), while IGF-1 was negatively associated with advanced fibrosis (OR 0.63 per standard deviation, 95%CI 0.44-0.92, p = .02). This pilot study suggests an association between serum IGFBP-1 and IGF-I levels with advanced fibrosis in NAFLD patients. IGFBP1 and IGF-1 could be of interest as future biomarkers. Similar studies in larger cohorts are needed.

  8. Follicle-stimulating hormone (FSH) activates extracellular signal-regulated kinase phosphorylation independently of beta-arrestin- and dynamin-mediated FSH receptor internalization

    Science.gov (United States)

    Piketty, Vincent; Kara, Elodie; Guillou, Florian; Reiter, Eric; Crepieux, Pascale

    2006-01-01

    Background The follicle-stimulating hormone receptor (FSH-R) is a seven transmembrane spanning receptor (7TMR) which plays a crucial role in male and female reproduction. Upon FSH stimulation, the FSH-R activates the extracellular signal-regulated kinases (ERK). However, the mechanisms whereby the agonist-stimulated FSH-R activates ERK are poorly understood. In order to activate ERK, some 7 TMRs require beta-arrestin-and dynamin-dependent internalization to occur, whereas some others do not. In the present study, we examined the ability of the FSH-activated FSH-R to induce ERK phosphorylation, in conditions where its beta-arrestin- and dynamin-mediated internalization was impaired. Methods Human embryonic kidney (HEK) 293 cells were transiently transfected with the rat FSH-R. Internalization of the FSH-R was manipulated by co-expression of either a beta-arrestin (319–418) dominant negative peptide, either an inactive dynamin K44A mutant or of wild-type beta-arrestin 1 or 2. The outcomes on the FSH-R internalization were assayed by measuring 125I-FSH binding at the cell surface when compared to internalized 125I-FSH binding. The resulting ERK phosphorylation level was visualized by Western blot analysis. Results In HEK 293 cells, FSH stimulated ERK phosphorylation in a dose-dependent manner. Co-transfection of the beta- arrestin (319–418) construct, or of the dynamin K44A mutant reduced FSH-R internalization in response to FSH, without affecting ERK phosphorylation. Likewise, overexpression of wild-type beta-arrestin 1 or 2 significantly increased the FSH-R internalization level in response to FSH, without altering FSH-induced ERK phosphorylation. Conclusion From these results, we conclude that the FSH-R does not require beta-arrestin- nor dynamin-mediated internalization to initiate ERK phosphorylation in response to FSH. PMID:16787538

  9. Activation of IGF-1 and insulin signaling pathways ameliorate mitochondrial function and energy metabolism in Huntington's Disease human lymphoblasts.

    Science.gov (United States)

    Naia, Luana; Ferreira, I Luísa; Cunha-Oliveira, Teresa; Duarte, Ana I; Ribeiro, Márcio; Rosenstock, Tatiana R; Laço, Mário N; Ribeiro, Maria J; Oliveira, Catarina R; Saudou, Frédéric; Humbert, Sandrine; Rego, A Cristina

    2015-02-01

    Huntington's disease (HD) is an inherited neurodegenerative disease caused by a polyglutamine repeat expansion in the huntingtin protein. Mitochondrial dysfunction associated with energy failure plays an important role in this untreated pathology. In the present work, we used lymphoblasts obtained from HD patients or unaffected parentally related individuals to study the protective role of insulin-like growth factor 1 (IGF-1) versus insulin (at low nM) on signaling and metabolic and mitochondrial functions. Deregulation of intracellular signaling pathways linked to activation of insulin and IGF-1 receptors (IR,IGF-1R), Akt, and ERK was largely restored by IGF-1 and, at a less extent, by insulin in HD human lymphoblasts. Importantly, both neurotrophic factors stimulated huntingtin phosphorylation at Ser421 in HD cells. IGF-1 and insulin also rescued energy levels in HD peripheral cells, as evaluated by increased ATP and phosphocreatine, and decreased lactate levels. Moreover, IGF-1 effectively ameliorated O2 consumption and mitochondrial membrane potential (Δψm) in HD lymphoblasts, which occurred concomitantly with increased levels of cytochrome c. Indeed, constitutive phosphorylation of huntingtin was able to restore the Δψm in lymphoblasts expressing an abnormal expansion of polyglutamines. HD lymphoblasts further exhibited increased intracellular Ca(2+) levels before and after exposure to hydrogen peroxide (H2O2), and decreased mitochondrial Ca(2+) accumulation, being the later recovered by IGF-1 and insulin in HD lymphoblasts pre-exposed to H2O2. In summary, the data support an important role for IR/IGF-1R mediated activation of signaling pathways and improved mitochondrial and metabolic function in HD human lymphoblasts.

  10. The effect of epidermal growth factor and IGF-I infusion on hepatic and renal expression of the IGF-system in adult female rats

    NARCIS (Netherlands)

    J.W. van Neck (Han); E.M. Berghout; L. Vinter-Jensen; C.A.H. Groffen; V. Cingel-Ristic; N.F. Dits (Natasja); S.L.S. Drop (Stenvert); A. Flyvbjerg (Allan)

    2000-01-01

    textabstractSystemic administration of epidermal growth factor (EGF) in neonatal rats results in reduced body weight gain and decreased circulating levels of IGF-I, suggesting its involvement in EGF-induced growth retardation. We investigated the effect of EGF and/or IGF-I

  11. Subcutaneous administration of insulin-like growth factor (IGF)-II/IGF binding protein-2 complex stimulates bone formation and prevents loss of bone mineral density in a rat model of disuse osteoporosis

    Science.gov (United States)

    Conover, Cheryl A.; Johnstone, Edward W.; Turner, Russell T.; Evans, Glenda L.; John Ballard, F. John; Doran, Patrick M.; Khosla, Sundeep

    2002-01-01

    Elevated serum levels of insulin-like growth factor binding protein-2 (IGFBP-2) and a precursor form of IGF-II are associated with marked increases in bone formation and skeletal mass in patients with hepatitis C-associated osteosclerosis. In vitro studies indicate that IGF-II in complex with IGFBP-2 has high affinity for bone matrix and is able to stimulate osteoblast proliferation. The purpose of this study was to determine the ability of the IGF-II/IGFBP-2 complex to increase bone mass in vivo. Osteopenia of the femur was induced by unilateral sciatic neurectomy in rats. At the time of surgery, 14-day osmotic minipumps containing vehicle or 2 microg IGF-II+9 microg IGFBP-2/100g body weight/day were implanted subcutaneously in the neck. Bone mineral density (BMD) measurements were taken the day of surgery and 14 days later using a PIXImus small animal densitometer. Neurectomy of the right hindlimb resulted in a 9% decrease in right femur BMD (Ploss in BMD was completely prevented by treatment with IGF-II/IGFBP-2. On the control limb, there was no loss of BMD over the 14 days and IGF-II/IGFBP-2 treatment resulted in a 9% increase in left femur BMD (Ploss of BMD associated with disuse osteoporosis and stimulate bone formation in adult rats. Furthermore, they provide proof of concept for a novel anabolic approach to increasing bone mass in humans with osteoporosis.

  12. Dietary protein-induced hepatic IGF-1 secretion mediated by PPARγ activation.

    Science.gov (United States)

    Wan, Xiaojuan; Wang, Songbo; Xu, Jingren; Zhuang, Lu; Xing, Kongping; Zhang, Mengyuan; Zhu, Xiaotong; Wang, Lina; Gao, Ping; Xi, Qianyun; Sun, Jiajie; Zhang, Yongliang; Li, Tiejun; Shu, Gang; Jiang, Qingyan

    2017-01-01

    Dietary protein or amino acid (AA) is a crucial nutritional factor to regulate hepatic insulin-like growth factor-1 (IGF-1) expression and secretion. However, the underlying intracellular mechanism by which dietary protein or AA induces IGF-1 expression remains unknown. We compared the IGF-1 gene expression and plasma IGF-1 level of pigs fed with normal crude protein (CP, 20%) and low-protein levels (LP, 14%). RNA sequencing (RNA-seq) was performed to detect transcript expression in the liver in response to dietary protein. The results showed that serum concentrations and mRNA levels of IGF-1 in the liver were higher in the CP group than in the LP group. RNA-seq analysis identified a total of 1319 differentially expressed transcripts (667 upregulated and 652 downregulated), among which the terms "oxidative phosphorylation", "ribosome", "gap junction", "PPAR signaling pathway", and "focal adhesion" were enriched. In addition, the porcine primary hepatocyte and HepG2 cell models also demonstrated that the mRNA and protein levels of IGF-1 and PPARγ increased with the increasing AA concentration in the culture. The PPARγ activator troglitazone increased IGF-1 gene expression and secretion in a dose dependent manner. Furthermore, inhibition of PPARγ effectively reversed the effects of the high AA concentration on the mRNA expression of IGF-1 and IGFBP-1 in HepG2 cells. Moreover, the protein levels of IGF-1 and PPARγ, as well as the phosphorylation of mTOR, significantly increased in HepG2 cells under high AA concentrations. mTOR phosphorylation can be decreased by the mTOR antagonist, rapamycin. The immunoprecipitation results also showed that high AA concentrations significantly increased the interaction of mTOR and PPARγ. In summary, PPARγ plays an important role in the regulation of IGF-1 secretion and gene expression in response to dietary protein.

  13. Gender and age influence the relationship between serum GH and IGF-I in patients with acromegaly.

    Science.gov (United States)

    Parkinson, C; Renehan, A G; Ryder, W D J; O'Dwyer, S T; Shalet, S M; Trainer, P J

    2002-07-01

    In patients with acromegaly serum IGF-I is increasingly used as a marker of disease activity. As a result, the relationship between serum GH and IGF-I is of profound interest. Healthy females secrete three times more GH than males but have broadly similar serum IGF-I levels, and women with GH deficiency require 30-50% more exogenous GH to maintain the same serum IGF-I as GH-deficient men. In a selected cohort of patients with active acromegaly, studied off medical therapy using a single fasting serum GH and IGF-I measurement, we have reported previously that, for a given GH level, women have significantly lower circulating IGF-I. To evaluate the influence of age and gender on the relationship between serum GH and IGF-I in an unselected cohort of patients with acromegaly independent of disease control and medical therapy. Sixty (34 male) unselected patients with acromegaly (median age 51 years (range 24-81 years) attending a colonoscopy screening programme were studied. Forty-five had previously received pituitary radiotherapy. Patients had varying degrees of disease control and received medical therapy where appropriate. Mean serum GH was calculated from an eight-point day profile (n = 45) and values obtained during a 75-g oral glucose tolerance test (n = 15). Serum IGF-I, IGFBP-3 and acid-labile subunit were measured and the dependency of these factors on covariates such as log10 mean serum GH, sex, age and prior radiotherapy was assessed using regression techniques. The median calculated GH value was 4.7 mU/l (range 1-104). A significant linear association was observed between serum IGF-I and log10 mean serum GH for the cohort (R = 0.5, P fall by 0.37 nmol/l per year (P = 0.04, 95% CI 0.015-0.72). In keeping with previous observations of relative GH resistance in normal and GH-deficient females we have observed lower serum IGF-I levels for equivalent mean serum GH levels in females patients with acromegaly. This gender-dependent difference is independent of

  14. Subcutaneous administration of insulin-like growth factor (IGF)-II/IGF binding protein-2 complex stimulates bone formation and prevents loss of bone mineral density in a rat model of disuse osteoporosis

    Science.gov (United States)

    Conover, Cheryl A.; Johnstone, Edward W.; Turner, Russell T.; Evans, Glenda L.; John Ballard, F. John; Doran, Patrick M.; Khosla, Sundeep

    2002-01-01

    Elevated serum levels of insulin-like growth factor binding protein-2 (IGFBP-2) and a precursor form of IGF-II are associated with marked increases in bone formation and skeletal mass in patients with hepatitis C-associated osteosclerosis. In vitro studies indicate that IGF-II in complex with IGFBP-2 has high affinity for bone matrix and is able to stimulate osteoblast proliferation. The purpose of this study was to determine the ability of the IGF-II/IGFBP-2 complex to increase bone mass in vivo. Osteopenia of the femur was induced by unilateral sciatic neurectomy in rats. At the time of surgery, 14-day osmotic minipumps containing vehicle or 2 microg IGF-II+9 microg IGFBP-2/100g body weight/day were implanted subcutaneously in the neck. Bone mineral density (BMD) measurements were taken the day of surgery and 14 days later using a PIXImus small animal densitometer. Neurectomy of the right hindlimb resulted in a 9% decrease in right femur BMD (P<0.05 vs. baseline). This loss in BMD was completely prevented by treatment with IGF-II/IGFBP-2. On the control limb, there was no loss of BMD over the 14 days and IGF-II/IGFBP-2 treatment resulted in a 9% increase in left femur BMD (P<0.05). Bone histomorphometry indicated increases in endocortical and cancellous bone formation rates and in trabecular thickness. These results demonstrate that short-term administration of the IGF-II/IGFBP-2 complex can prevent loss of BMD associated with disuse osteoporosis and stimulate bone formation in adult rats. Furthermore, they provide proof of concept for a novel anabolic approach to increasing bone mass in humans with osteoporosis.

  15. Insulin-Like Growth Factor I (IGF-1) Deficiency Ameliorates Sex Difference in Cardiac Contractile Function and Intracellular Ca2+ Homeostasis

    Science.gov (United States)

    Ceylan-Isik, Asli F.; Li, Qun; Ren, Jun

    2011-01-01

    Sex difference in cardiac contractile function exists which may contribute to the different prevalence in cardiovascular diseases between genders. However, the precise mechanisms of action behind sex difference in cardiac function are still elusive. Given that sex difference exists in insulin-like growth factor I (IGF-1) cascade, this study is designed to evaluate the impact of severe liver IGF-1 deficiency (LID) on sex difference in cardiac function. Echocardiographic, cardiomyocyte contractile and intracellular Ca2+ properties were evaluated including ventricular geometry, fractional shortening, peak shortening, maximal velocity of shortening/relengthening (± dL/dt), time-to-peak shortening (TPS), time-to-90% relengthening (TR90), fura-fluorescence intensity (FFI) and intracellular Ca2+ clearance. Female C57 mice exhibited significantly higher plasma IGF-1 levels than their male counterpart. LID mice possessed comparably low IGF-1 levels in both sexes. Female C57 and LID mice displayed lower body, heart and liver weights compared to male counterparts. Echocardiographic analysis revealed larger LV mass in female C57 but not LID mice without sex difference in other cardiac geometric indices. Myocytes from female C57 mice exhibited reduced peak shortening, ± dL/dt, longer TPS, TR90 and intracellular Ca2+ clearance compared with males. Interestingly, this sex difference was greatly attenuated or abolished by IGF-1 deficiency. Female C57 mice displayed significantly decreased mRNA and protein levels of Na+-Ca2+ exchanger, SERCA2a and phosphorylated phospholamban as well as SERCA activity compared with male C57 mice. These sex differences in Ca2+ regulatory proteins were abolished or overtly attenuated by IGF-1 deficiency. In summary, our data suggested that IGF-1 deficiency may significantly attenuated or mitigate the sex difference in cardiomyocyte contractile function associated with intracellular Ca2+ regulation. PMID:21763763

  16. Insulin-like growth factor I (IGF-1) deficiency ameliorates sex difference in cardiac contractile function and intracellular Ca(2+) homeostasis.

    Science.gov (United States)

    Ceylan-Isik, Asli F; Li, Qun; Ren, Jun

    2011-10-10

    Sex difference in cardiac contractile function exists which may contribute to the different prevalence in cardiovascular diseases between genders. However, the precise mechanisms of action behind sex difference in cardiac function are still elusive. Given that sex difference exists in insulin-like growth factor I (IGF-1) cascade, this study is designed to evaluate the impact of severe liver IGF-1 deficiency (LID) on sex difference in cardiac function. Echocardiographic, cardiomyocyte contractile and intracellular Ca(2+) properties were evaluated including ventricular geometry, fractional shortening, peak shortening, maximal velocity of shortening/relengthening (±dL/dt), time-to-peak shortening (TPS), time-to-90% relengthening (TR(90)), fura-fluorescence intensity (FFI) and intracellular Ca(2+) clearance. Female C57 mice exhibited significantly higher plasma IGF-1 levels than their male counterpart. LID mice possessed comparably low IGF-1 levels in both sexes. Female C57 and LID mice displayed lower body, heart and liver weights compared to male counterparts. Echocardiographic analysis revealed larger LV mass in female C57 but not LID mice without sex difference in other cardiac geometric indices. Myocytes from female C57 mice exhibited reduced peak shortening, ±dL/dt, longer TPS, TR(90) and intracellular Ca(2+) clearance compared with males. Interestingly, this sex difference was greatly attenuated or abolished by IGF-1 deficiency. Female C57 mice displayed significantly decreased mRNA and protein levels of Na(+)-Ca(2+) exchanger, SERCA2a and phosphorylated phospholamban as well as SERCA activity compared with male C57 mice. These sex differences in Ca(2+) regulatory proteins were abolished or overtly attenuated by IGF-1 deficiency. In summary, our data suggested that IGF-1 deficiency may significantly attenuated or mitigate the sex difference in cardiomyocyte contractile function associated with intracellular Ca(2+) regulation. Copyright © 2011 Elsevier Ireland

  17. IGF-binding proteins mediate TGF-beta 1-induced apoptosis in bovine mammary epithelial BME-UV1 cells.

    Science.gov (United States)

    Gajewska, Małgorzata; Motyl, Tomasz

    2004-10-01

    TGF-beta 1 is an antiproliferative and apoptogenic factor for mammary epithelial cells (MEC) acting in an auto/paracrine manner and thus considered an important local regulator of mammary tissue involution. However, the apoptogenic signaling pathway induced by this cytokine in bovine MEC remains obscure. The present study was focused on identification of molecules involved in apoptogenic signaling of transforming growth factor-beta 1 (TGF-beta 1) in the model of bovine mammary epithelial cell line (BME-UV1). Laser scanning cytometry (LSC), Western blot and electrophoretic mobility shift assay (EMSA) were used for analysis of expression and activity of TGF-beta 1-related signaling molecules. The earliest response occurring within 1-2 h after TGF-beta 1 administration was an induction and activation of R-Smads (Smad2 and Smad3) and Co-Smad (Smad4). An evident formation of Smad-DNA complexes began from 2nd hour after MEC exposure to TGF-beta 1. Similarly to Smads, proteins of AP1 complex: phosphorylated c-Jun and JunD appeared to be early reactive molecules; however, an increase in their expression was detected only in cytosolic fraction. In the next step, an increase of IGF binding protein-3 (IGFBP-3) and IGFBP-4 expression was observed from 6th hour followed by a decrease in the activity of protein kinase B (PKB/Akt), which occurred after 24 h of MEC exposure to TGF-beta 1. The decrease in PKB/Akt activity coincided in time with the decline of phosphorylated Bad expression (inactive form). Present study supported additional evidence that stimulation of insulin-like growth factor I (IGF-I) was associated with complete abrogation of TGF-beta 1-induced activation of Bad and Bax and in the consequence protection against apoptosis. In conclusion, apoptotic effect of TGF-beta 1 in bovine MEC is mediated by IGFBPs and occurs through IGF-I sequestration, resulting in inhibition of PKB/Akt-dependent survival pathway.

  18. Comparisons of mRNA expression for insulin-like growth factor (IGF) type 2 receptor (IGF2R) and IGF-1 in small ovarian follicles between cattle selected and not selected for twin ovulations

    Science.gov (United States)

    Both IGF-1 and -2 stimulate ovarian follicular cell proliferation and antral follicle development. Actions of IGF-1 and -2 are mediated through the IGF type 1 receptor, whereas binding of IGF-2 to the IGF2R results in its degradation. Information on the role of IGF2R in regulating bovine follicula...

  19. Role of Ubiquitination in IGF-1 Receptor Signaling and Degradation

    OpenAIRE

    Sehat, Bita; Andersson, Sandra; Vasilcanu, Radu; Girnita, Leonard; Larsson, Olle

    2007-01-01

    BACKGROUND: The insulin-like growth factor 1 receptor (IGF-1R) plays numerous crucial roles in cancer biology. The majority of knowledge on IGF-1R signaling is concerned with its role in the activation of the canonical phosphatidyl inositol-3 kinase (PI3K)/Akt and MAPK/ERK pathways. However, the role of IGF-1R ubiquitination in modulating IGF-1R function is an area of current research. In light of this we sought to determine the relationship between IGF-1R phosphorylation, ubiquitination, and...

  20. Differential basal and exercise-induced IGF-I system responses to resistance vs. calisthenic-based military readiness training programs.

    Science.gov (United States)

    Nindl, Bradley C; Alemany, Joseph A; Rarick, Kevin R; Eagle, Shawn R; Darnell, Mathew E; Allison, Katelyn F; Harman, Everett A

    2017-02-01

    The purpose of this study was to: 1) evaluate differential responses of the IGF-I system to either a calisthenic- or resistance exercise-based program and 2) determine if this chronic training altered the IGF-I system during an acute resistance exercise protocol. Thirty-two volunteers were randomly assigned into a resistance exercise-based training (RT) group (n=15, 27±5y, 174±6cm, 81±12kg) or a calisthenic-based training group (CT) (n=17, 29±5y, 179±8cm, 85±10kg) and all underwent 8weeks of exercise training (1.5h/d, 5d/wk). Basal blood was sampled pre- (Week 0), mid- (Week 4) and post-training (Week 8) and assayed for IGF-I system analytes. An acute resistance exercise protocol (AREP) was conducted preand post-training consisting of 6 sets of 10 repetitions in the squat with two minutes of rest in between sets and the IGF-I system analytes measured. A repeated measures ANOVA (p≤0.05) was used for statistical analysis. No interaction or within-subject effects were observed for basal total IGF-I, free IGF-I, or IGFBP-1. IGFBP-2 (pre; 578.6±295.7post-training; 14.3±1.9μg/mL; p=0.01). An interaction was observed for the RT group as IGFBP-3 increased from pre to mid (3462.4±216.4 vs. 3962.2±227.9ng/mL), but was not significant at the post-training time point (3770.3±228.7ng/mL). AREP caused all analytes except free IGF-I (40% decrease) to increase (17-27%; p=0.001) during exercise, returning to baseline concentration into recovery. Post-training, bioavailable IGF-I recovered more rapidly post-exercise. 8wks of chronic physical training resulted in increased basal IGFBP-2 and IGFBP-3, decreased ALS, increased pre-AREP free IGF-I and a more rapid free IGF-I recovery post-AREP. While total IGF-I was insensitive to chronic physical training, changes were observed with circulating IGFBPs and bioavailable IGF-I. To glean the most robust information on the effects of exercise training, studies must move beyond relying solely on total IGF-I measures and should

  1. The effect of growth hormone on bioactive IGF in overweight/obese women.

    Science.gov (United States)

    Dichtel, Laura E; Bjerre, Mette; Schorr, Melanie; Bredella, Miriam A; Gerweck, Anu V; Russell, Brian M; Frystyk, Jan; Miller, Karen K

    2018-03-10

    Overweight/obesity is characterized by decreased growth hormone (GH) secretion whereas circulating IGF-I levels are less severely reduced. Yet, the activity of the circulating IGF-system appears to be normal in overweight/obese subjects, as estimated by the ability of serum to activate the IGF-I receptor in vitro (bioactive IGF). We hypothesized that preservation of bioactive IGF in overweight/obese women is regulated by an insulin-mediated suppression of IGF-binding protein-1 (IGFBP-1) and IGFBP-2, and by suppression of IGFBP-3, mediated by low GH. We additionally hypothesized that increases in bioactive IGF would drive changes in body composition with low-dose GH administration. Cross-sectional analysis and 3-month interim analysis of a 6-month randomized, placebo-controlled study of GH administration in 50 overweight/obese women without diabetes mellitus. Bioactive IGF (kinase receptor activation assay) and body composition (DXA) were measured. Prior to treatment, IGFBP-3 (r = -0.33, p = 0.02), but neither IGFBP-1 nor IGFBP-2, associated inversely with bioactive IGF. In multivariate analysis, lower IGFBP-3 correlated with lower peak stimulated GH (r = 0.45, p = 0.05) and higher insulin sensitivity (r = -0.74, p = 0.003). GH administration resulted in an increase in mean serum IGF-I concentrations (144 ± 56 to 269 ± 66 μg/L, p IGF (1.29 ± 0.39 to 2.60 ± 1.12 μg/L, p IGF, but not total IGF-I concentration, predicted an increase in lean mass (r = 0.31, p = 0.03) and decrease in total adipose tissue/BMI (r = -0.43, p = 0.003). Our data suggest that in overweight/obesity, insulin sensitivity and GH have opposing effects on IGF bioactivity through effects on IGFBP-3. Furthermore, increases in bioactive IGF, rather than IGF-I concentration, predicted GH administration-related body composition changes. NCT00131378. Copyright © 2018. Published by Elsevier Ltd.

  2. Differential effects of hGH and IGF-I on body proportions.

    Science.gov (United States)

    Laron, Zvi; Silbergeld, Aviva; Kauli, Rivka

    2012-07-01

    The differential growth effects of hGH and IGF-I on the upper/lower (U/L) body segment in relation to height (Ht) were analyzed in 15 patients with isolated Growth hormone deficiency (IGHD,:7M, 8F) mean age 5.0 +/- 3.2 (SD) years treated with hGH; 21 patients with multiple pituitary hormone deficiency including growth hormone (MPHD: 14M, 7F) aged 10.0 +/- 3.8, treated with hGH; 9 patients with Laron Syndrome (LS) (4M,5F) aged 6.9 +/- 5.6 years treated with IGF-I; 9 boys with intrauterine growth retardation (IUGR) aged 6.3 +/- 1.25 years treated by hGH; and 22 boys with idiopathic short stature (ISS) aged 8.0 +/- 1.55 years treated by hGH. The dose of hGH was 33 microg/kg/day, that of IGF-I 180-200 microg/kg/day. the U/L body segment ratio in IGHD patients decreased from 2.3 +/- 0.7 to 1.1 +/- 0.7 (p <0.001), and the Ht SDS increased from -4.9 +/- 1.3 to 2.3 +/- 1 (p < 0.001) following treatment. In MPHD patients the U/L body segment decreased from 1.1 +/- 1.1 to -0.6 +/- 1.0 (p < 0.001), and the Ht SDS increased from -3.3 +/- 1.4 to -2.5 +/- 1.0 (p < 0.009). In the LS group the U/L body segment ratio did not change with IGF-I treatment but Ht improved from -6.1 +/- 1.3 to -4.6 +/- 1.2 (p < 0.001), The differential growth response of the children with IUGR and with ISS resembled that of the children with LS. hGH and IGF-I act differentially on the spine and limbs.

  3. Interaction of insulin-like growth factor I with porcine thyroid cells cultured in monolayer

    International Nuclear Information System (INIS)

    Saji, M.; Tsushima, T.; Isozaki, O.; Murakami, H.; Ohba, Y.; Sato, K.; Arai, M.; Mariko, A.; Shizume, K.

    1987-01-01

    The interaction of insulin-like growth factor I (IGF-I) with porcine thyroid cells cultured in monolayer was studied. Specific binding of [ 125 I]iodo-IGF-I to thyroid cells was a reversible process dependent on the time and temperature of incubation. A steady state was achieved in 18 h at 4 C and averaged 14.2 +/- 2% (mean +/- SD)/10(6) cells. Binding of [ 125 I]iodo-IGF-I was inhibited by unlabeled IGF-I; half-maximal inhibition occurred at concentrations of 2-5 ng/ml. Multiplication-stimulating activity (rat IGF-II) and pork insulin had relative potencies of 1:20 and 1:300 compared with IGF-I. Scatchard analysis of binding data revealed a single class of IGF-I receptors with a Ka of 4.3 X 10(10) M-1, 49,000 binding sites were estimated per cell. Affinity cross-linking and autoradiography demonstrated the presence of type I IGF receptors. Thyroid cells also had specific receptors for insulin, but specific binding of [ 125 I]iodoinsulin was much lower than that of [ 125 I]iodo-IGF-I. Preincubation of thyroid cells with IGF-I or insulin caused a concentration-dependent decrease in [ 125 I]iodo-IGF-I binding due to an apparent loss of receptors. Preincubation with epidermal growth factor, fibroblast growth factor, platelet-derived growth factor, or TSH did not alter subsequent binding of [ 125 I]iodo-IGF-I. Low concentrations of IGF-I stimulated DNA synthesis and proliferation of thyroid cells and acted synergistically with epidermal growth factor. Multiplication-stimulating activity and insulin had relative potencies in stimulating DNA synthesis comparable to their abilities to inhibit the binding of [ 125 I]iodo-IGF-I to thyroid cells

  4. The IGF-I/IGFBP-3 system in gingival crevicular fluid and dependence on application of fixed force.

    Science.gov (United States)

    Toia, M; Galazzo, R; Maioli, C; Granata, R; Scarlatti, F

    2005-12-01

    During application of orthodontic force on the tooth, various molecular parameters associated with tissue remodeling are changed. IGF-I is a regulatory protein produced during periodontal regeneration. IGF binding proteins-3 (IGFBP-3), a specific IGF-I binding protein, is the major regulatory factor of IGF-I activity. We tested the hypothesis that changes in the IGF-I/ IGFBP-3 system occur during fixed force application to the tooth and that these changes are detectable in the gingival crevicular fluid (GCF). IGFBP-3 and IGF-I secretion into gingival crevicular fluid (GCF) was analyzed by Western blotting and immunoradiometric assay (IRMA), respectively, in GCF of 6 healthy subjects just prior to and during orthodontics treatment using fixed appliances. We observed a significant time-dependent decrease of IGFBP-3 content in GCF during orthodontic treatment (4 h and 10 days). Reduction in levels of intact, glycosylated 47 kDa form of IGFBP-3 was associated with its degradation and the appearance of intermediate breakdown products. IGF-I levels were significantly increased 4 h after application of orthodontic force, while they were significantly reduced 10 days after the start of treatment. IGFBP-3 secretion into GCF and its molecular structure are modified by the fixed force of orthodontic treatment. Alterations in IGFBP-3 appear to be unrelated to the binding to IGF-I, suggesting an IGF-independent role of this binding protein in tooth movement.

  5. Targeting either GH or IGF-I during somatostatin analogue treatment in patients with acromegaly

    DEFF Research Database (Denmark)

    Dal, Jakob; Klose, Marianne; Heck, Ansgar

    2018-01-01

    CONTEXT: Discordant GH and IGF-I values are frequent in acromegaly. The clinical significance and its dependence on treatment modality and of glucose-suppressed GH (GHnadir) measurements remain uncertain. OBJECTIVE: To evaluate the effects of targeting either IGF-I or GH during somatostatin analog...... (SA) treatment. PATIENTS AND METHODS: 84 patients with controlled acromegaly after surgery (n=23) or SA (n=61) underwent a GH-profile including an OGTT, at baseline and after 12 months. SA patients were randomized to monitoring according to either IGF-I (n= 33) or GHnadir (n=28). SA dose escalation...

  6. Clinical significance of determination of serum IGF-I and SIL-2R levels in patients with prostatic cancer

    International Nuclear Information System (INIS)

    Zhang Zaigao; Lv Yuliang; Li Jiacheng

    2006-01-01

    Objective: To investigate the significance of changes of serum IGF-I and SIL-2R levels in patients with prostatic cancer. Methods: Serum IGF-I levels (with RIA) and SIL-2R levels (with ELISA) were measured in 31 patients with prostatic cancer and 30 controls. Results: Serum levels of IGF-I and SIL-2R in the 31 patients were significantly higher than those in controls (P<0.01), serum IGF-I and SIL-2R levels were mutually positively correlated (r=0.6182, P<0.01). Conclusion: Serum IGF-I and SIL-2R were useful markers for prostatic cancer. (authors)

  7. Study on the correlationship between serum IGF-I and HA, PIIIP levels in patients with chronic hepatitis C

    International Nuclear Information System (INIS)

    Li Yong; Sun Yefu; Xia Aiping

    2008-01-01

    Objective: To study the inter-relationship between serum IGF-I and HA, PIIIP levels in patients with chronic hepatitis C. Methods: Serum IGF-I, HA and PIIIP levels were determined with RIA in 39 patients with chronic hepatitis C and 35 controls. Results: Serum IGF-I, HA and PIIIP levels in the patients were significantly higher than those in controls (P<0.01). The serum IGF-I levels and HA, PIIIP levels were mutually positively correlated (r=0.8018, 0.7126, P<0.01). Conclusion: Serum IGF-I, HA and PIIIP were useful diagnostic markers in patients with chronic hepatitis C. (authors)

  8. Effect of insulin analogues on insulin/IGF1 hybrid receptors: increased activation by glargine but not by its metabolites M1 and M2.

    Directory of Open Access Journals (Sweden)

    Cécile Pierre-Eugene

    Full Text Available BACKGROUND: In diabetic patients, the pharmacokinetics of injected human insulin does not permit optimal control of glycemia. Fast and slow acting insulin analogues have been developed, but they may have adverse properties, such as increased mitogenic or anti-apoptotic signaling. Insulin/IGF1 hybrid receptors (IR/IGF1R, present in most tissues, have been proposed to transmit biological effects close to those of IGF1R. However, the study of hybrid receptors is difficult because of the presence of IR and IGF1R homodimers. Our objective was to perform the first study on the pharmacological properties of the five marketed insulin analogues towards IR/IGF1R hybrids. METHODOLOGY: To study the effect of insulin analogues on IR/IGF1R hybrids, we used our previously developed Bioluminescence Resonance Energy Transfer (BRET assay that permits specific analysis of the pharmacological properties of hybrid receptors. Moreover, we have developed a new, highly sensitive BRET-based assay to monitor phophatidylinositol-3 phosphate (PIP(3 production in living cells. Using this assay, we performed a detailed pharmacological analysis of PIP(3 production induced by IGF1, insulin and insulin analogues in living breast cancer-derived MCF-7 and MDA-MB231 cells. RESULTS: Among the five insulin analogues tested, only glargine stimulated IR/IGF1R hybrids with an EC50 that was significantly lower than insulin and close to that of IGF1. Glargine more efficiently stimulated PIP(3 production in MCF-7 cells but not in MDA-MB231 cells as compared to insulin. In contrast, glargine metabolites M1 and M2 showed lower potency for hybrid receptors stimulation, PIP(3 production, Akt and Erk1/2 phosphorylation and DNA synthesis in MCF-7 cells, compared to insulin. CONCLUSION: Glargine, possibly acting through IR/IGF1R hybrids, displays higher potency, whereas its metabolites M1 and M2 display lower potency than insulin for the stimulation of proliferative/anti-apoptotic pathways in

  9. Effects of short-term caloric restriction on circulating free IGF-I, acid-labile subunit, IGF-binding proteins (IGFBPs)-1-4, and IGFBPs-1-3 protease activity in obese subjects

    DEFF Research Database (Denmark)

    Rasmussen, Michael Højby; Juul, Anders; Kjems, Lise Lund

    2006-01-01

    , no published data exist on free IGF-I levels, acid labile subunit (ALS), or IGFBP protease activity in relation to GH release during a hypocaloric diet. The main purpose of this study was to determine free IGF-I, ALS, IGFBPs-1-4, and IGFBPs-1-3 protease activity in relation to 24-h GH release before and after......Decreased levels of GH and total IGF-I have been reported in obesity. It has been hypothesized that increased free (biologically active) IGF-I levels generated from IGF-binding protein (IGFBP) protease activity could be the mechanism for the low GH release in dieting obese subjects. However...... a short-term very low-calorie diet (VLCD)....

  10. Effects of short-term caloric restriction on circulating free IGF-I, acid-labile subunit, IGF-binding proteins (IGFBPs)-1-4, and IGFBPs-1-3 protease activity in obese subjects

    DEFF Research Database (Denmark)

    Rasmussen, Michael Højby; Juul, Anders; Kjems, Lise Lund

    2006-01-01

    Decreased levels of GH and total IGF-I have been reported in obesity. It has been hypothesized that increased free (biologically active) IGF-I levels generated from IGF-binding protein (IGFBP) protease activity could be the mechanism for the low GH release in dieting obese subjects. However......, no published data exist on free IGF-I levels, acid labile subunit (ALS), or IGFBP protease activity in relation to GH release during a hypocaloric diet. The main purpose of this study was to determine free IGF-I, ALS, IGFBPs-1-4, and IGFBPs-1-3 protease activity in relation to 24-h GH release before and after...... a short-term very low-calorie diet (VLCD)....

  11. IGF-I treatment improves the functional properties of fast- and slow-twitch skeletal muscles from dystrophic mice.

    Science.gov (United States)

    Lynch, G S; Cuffe, S A; Plant, D R; Gregorevic, P

    2001-04-01

    Although insulin-like growth factor-I (IGF-I) has been proposed for use by patients suffering from muscle wasting conditions, few studies have investigated the functional properties of dystrophic skeletal muscle following IGF-I treatment. 129P1 ReJ-Lama2(dy) (129 ReJ dy/dy) dystrophic mice suffer from a deficiency in the structural protein, laminin, and exhibit severe muscle wasting and weakness. We tested the hypothesis that 4 weeks of IGF-I treatment ( approximately 2 mg/kg body mass, 50 g/h via mini-osmotic pump, subcutaneously) would increase the mass and force producing capacity of skeletal muscles from dystrophic mice. IGF-I treatment increased the mass of the extensor digitorum longus (EDL) and soleus muscles of dystrophic mice by 20 and 29%, respectively, compared with untreated dystrophic mice (administered saline-vehicle only). Absolute maximum force (P(o)) of the EDL and soleus muscle was increased by 40 and 32%, respectively, following IGF-I treatment. Specific P(o) (sP(o)) was increased by 23% in the EDL muscles of treated compared with untreated mice, but in the soleus muscle sP(o) was unchanged. IGF-I treatment increased the proportion of type IIB and type IIA fibres and decreased the proportion of type I fibres in the EDL muscles of dystrophic mice. In the soleus muscles of dystrophic mice, IGF-I treatment increased the proportion of type IIA fibres and decreased the proportion of type I fibres. Average fibre cross-sectional area was increased in the EDL and soleus muscles of treated compared with untreated mice. We conclude that IGF-I treatment ameliorates muscle wasting and improves the functional properties of skeletal muscles of dystrophic mice. The findings have important implications for the role of IGF-I in ameliorating muscle wasting associated with the muscular dystrophies.

  12. Detection of polymorphism of the insulin-like growth factor-I (IGF-I ...

    African Journals Online (AJOL)

    Molecular genetic selection on individual genes is a promising method to genetically improve economically important traits in chickens. The insulin-like growth factor-I (IGF-I) gene may play important roles in growth of multiple tissues, including muscle cells, cartilage and bone. In the present study, polymorphism of the ...

  13. IGF-I AND FGF-2 RESPONSES TO WINGATE ANAEROBIC TEST IN OLDER MEN

    Directory of Open Access Journals (Sweden)

    Ruthie Amir

    2007-06-01

    Full Text Available Reduced activity of the potent anabolic effectors: insulin-like growth factor-I (IGF-I and fibroblast growth factor-2 (FGF-2, play a role in aging associated muscle loss. The effect of fitness level on IGF-I and FGF-2 responses to all-out anaerobic exercise in older men was studied. Twenty four healthy older males: 12 higher fit (58 ± 1y and 12 lower fit (59 ± 1y underwent the Wingate anaerobic test. Serum levels of IGF-I and FGF-2 were measured before, immediately after exercise, and 50 min into recovery. Immediately post exercise, the average peak power output and serum lactate were higher (p < 0.05 in the higher fit (446.0 ± 14. 9 kgm·min-1 for mean (± SD peak power and 12.6 ± 1.1 mml·l-1 for lactate compared with the lower fit individuals (284.0 ± 6.5 kgm·min-1 and 8.5 ± 0.7 mml·l-1, respectively. Pre-exercise IGF-I was lower and FGF-2 was higher in the higher fit (335.0 ± 54.0 ng·ml-1 and 1.6 ± 0.1 ng·ml-1, respectively compared with lower fit individuals (402.0 ± 50.0 ng·ml-1 and 1.4 ± 0.2 ng·ml-1, respectively. Following the anaerobic exercise, in both groups, FGF-2 decreased dramatically (p < 0.05; in the higher fit individuals FGF-2 level was 0.4 ± 0.1 pg·ml-1 compared to 0.1 ± 0.02 pg·ml-1 in the lower fit individuals. In contrast to FGF-2, IGF-I increased transiently to levels of 405.0 ± 62.0 ng·ml-1 in the higher fit individuals and to levels of 436 ± 57.0 ng·ml-1 in the lower fit individuals. However, the IGF-I elevation was significant (p < 0. 05 only in the higher fit individuals. In conclusion, the present study demonstrates that during aging, fitness level can alter circulating levels of IGF-I and FGF-2. Furthermore, fitness level can affect the response of both mediators to all-out anaerobic exercise.

  14. Elevated IGFBP3 levels in diabetic tears: a negative regulator of IGF-1 signaling in the corneal epithelium.

    Science.gov (United States)

    Wu, Yu-Chieh; Buckner, Benjamin R; Zhu, Meifang; Cavanagh, H Dwight; Robertson, Danielle M

    2012-04-01

    To determine the ratio of IGFBP3:IGF-1 in normal and diabetic human tears, and in telomerase-immortalized human corneal epithelial cells (hTCEpi) cultured under elevated glucose conditions and to correlate these changes with total and phosphorylated levels of IGF-1R. Tear samples were collected noninvasively from diabetic subjects and non-diabetic controls; corneal sensitivity was assessed using a Cochet-Bonnet Aesthesiometer. Conditioned media were collected following culture of hTCEpi cells in normal (5 mM) and elevated (25 mM) glucose conditions; mannitol was used as an osmotic control. IGFBP3, IGF-1, and phosphorylated IGF-1R levels were assessed by ELISA. IGFBP3 and IGF-1R mRNA were assessed by real-time polymerase chain reaction (PCR). Total and phosphorylated IGF-1R expression in whole cell lysates was assessed by western blot. There was a 2.8-fold increase in IGFBP3 in diabetic tears compared to non-diabetic controls (P=0.006); IGF-1 levels were not significantly altered. No difference in corneal sensitivity was detected between groups. The concentration of IGFBP3 in tears was independent of IGF-1. Consistent with human tear measurements in vivo, IGFBP3 secretion was increased 2.2 fold (Ptears compared to normal controls blocked phosphorylation of the IGF-1R by IGF-1 (Ptears may attenuate IGF-1R signaling in the diabetic cornea. A long-term increase in IGFBP3 may contribute to epithelial compromise and the pathogenesis of ocular surface complications reported in diabetes. Copyright © 2012 Elsevier Inc. All rights reserved.

  15. Endurance training-induced changes in the GH-IGF-I axis influence maximal muscle strength in previously untrained men.

    Science.gov (United States)

    Grandys, Marcin; Majerczak, Joanna; Kuczek, Piotr; Sztefko, Krystyna; Duda, Krzysztof; Zoladz, Jerzy A

    2017-02-01

    In this study we have determined the effects of 20weeks of endurance running training on the GH-IGF-I axis changes in the context of the skeletal muscle performance and physical capacity level. Before and after the endurance training program a maximal incremental exercise tests, a 1500m race and a muscle strength measurements were performed and the blood samples were taken to determine both resting as well as end-exercise serum growth hormone (GH), insulin-like growth hormone-I (IGF-I), insulin-like growth hormone binding protein-3 (IGFBP-3) and plasma interleukin-6 (IL-6) concentrations. 20weeks of endurance running training improved power output generated at the end of the maximal incremental test by 24% (P<0.012), 1500m running time by 13% (P<0.012) and maximal muscle strength by 9% (P<0.02). End-exercise IGF-I/IGFBP-3 ratio was decreased by 22% after the training (P<0.04) and the magnitude of IGF-I/IGFBP-3 ratio decrease (ΔIGF-I/IGFBP-3 ex ) was 2.3 times higher after the training (P<0.04). The magnitude of the exercise-induced changes in IGFBP-3 concentration was also significantly higher (P<0.04) and there was a trend toward lower end-exercise IGF-I concentration (P=0.08) after the training. These changes were accompanied by a significantly higher (30%) end-exercise IL-6 concentration (P<0.01) as well as by a 3.4 times higher magnitude of IL-6 increase (P<0.02) after the training. Moreover, there were strong positive correlations between changes in resting serum IGF-I concentration (ΔIGF-I res ) and IGF-I/IGFBP-3 ratio (ΔIGF-I/IGFBP-3 res ) and changes in muscle strength (ΔMVC) (r=0.95, P=0.0003 and r=0.90, P=0.002, respectively). The training-induced changes in the components of the GH-IGF-I axis may have additive effects on skeletal muscle performance and physical capacity improvement. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Insulin Resistance and the IGF-I-Cortical Bone Relationship in Children Ages 9 to 13 Years.

    Science.gov (United States)

    Kindler, Joseph M; Pollock, Norman K; Laing, Emma M; Oshri, Assaf; Jenkins, Nathan T; Isales, Carlos M; Hamrick, Mark W; Ding, Ke-Hong; Hausman, Dorothy B; McCabe, George P; Martin, Berdine R; Hill Gallant, Kathleen M; Warden, Stuart J; Weaver, Connie M; Peacock, Munro; Lewis, Richard D

    2017-07-01

    IGF-I is a pivotal hormone in pediatric musculoskeletal development. Although recent data suggest that the role of IGF-I in total body lean mass and total body bone mass accrual may be compromised in children with insulin resistance, cortical bone geometric outcomes have not been studied in this context. Therefore, we explored the influence of insulin resistance on the relationship between IGF-I and cortical bone in children. A secondary aim was to examine the influence of insulin resistance on the lean mass-dependent relationship between IGF-I and cortical bone. Children were otherwise healthy, early adolescent black and white boys and girls (ages 9 to 13 years) and were classified as having high (n = 147) or normal (n = 168) insulin resistance based on the homeostasis model assessment of insulin resistance (HOMA-IR). Cortical bone at the tibia diaphysis (66% site) and total body fat-free soft tissue mass (FFST) were measured by peripheral quantitative computed tomography (pQCT) and dual-energy X-ray absorptiometry (DXA), respectively. IGF-I, insulin, and glucose were measured in fasting sera and HOMA-IR was calculated. Children with high HOMA-IR had greater unadjusted IGF-I (p insulin resistance as a potential suppressor of IGF-I-dependent cortical bone development, though prospective studies are needed. © 2017 American Society for Bone and Mineral Research. © 2017 American Society for Bone and Mineral Research.

  17. Direct demonstration of rapid insulin-like growth factor II receptor internalization and recycling in rat adipocytes. Insulin stimulates 125I-insulin-like growth factor II degradation by modulating the IGF-II receptor recycling process

    International Nuclear Information System (INIS)

    Oka, Y.; Rozek, L.M.; Czech, M.P.

    1985-01-01

    The photoactive insulin-like growth factor (IGF)-II analogue 4-azidobenzoyl- 125 I-IGF-II was synthesized and used to label specifically and covalently the Mr = 250,000 Type II IGF receptor. When rat adipocytes are irradiated after a 10-min incubation with 4-azidobenzoyl- 125 I-IGF-II at 10 degrees C and immediately homogenized, most of the labeled IGF-II receptors are associated with the plasma membrane fraction, indicating that receptors accessible to the labeling reagent at low temperature are on the cell surface. However, when the photolabeled cells are incubated at 37 degrees C for various times before homogenization, labeled IGF-II receptors are rapidly internalized with a half-time of 3.5 min as evidenced by a loss from the plasma membrane fraction and a concomitant appearance in the low density microsome fraction. The steady state level of cell surface IGF-II receptors in the presence or absence of IGF-II remains constant under these conditions, demonstrating that IGF-II receptors rapidly recycle back to the cell surface at the same rate as receptor internalization. Using the above methodology, it is shown that acute insulin action: 1) increases the steady state number of cell surface IGF-II receptors; 2) increases the number of ligand-bound IGF-II receptors that are internalized per unit of time; and 3) increases the rate of cellular 125 I-IGF-II degradation by a process that is blocked by anti-IGF-II receptor antibody

  18. Telomerase activity promotes osteoblast differentiation by modulating IGF-signaling pathway

    DEFF Research Database (Denmark)

    Saeed, Hamid; Qiu, Weimin; Li, Chen

    2015-01-01

    -regulation of several components of insulin-like growth factor (IGF) signaling. Specifically, a significant increase in IGF-induced AKT phosphorylation and alkaline phosphatase (ALP) activity were observed in hMSC-TERT. Enhanced ALP activity was reduced in presence of IGF1 receptor inhibitor: picropodophyllin....... In addition, telomerase deficiency caused significant reduction in IGF signaling proteins in osteoblastic cells cultured from telomerase deficient mice (Terc (-/-)). The low bone mass exhibited by Terc (-/-) mice was associated with significant reduction in serum levels of IGF1 and IGFBP3 as well as reduced...... skeletal mRNA expression of Igf1, Igf2, Igf2r, Igfbp5 and Igfbp6. IGF1-induced osteoblast differentiation was also impaired in Terc (-/-) MSC. In conclusion, our data demonstrate that impaired IGF/AKT signaling contributes to the observed decreased bone mass and bone formation exhibited by telomerase...

  19. Gastric cancer: the role of insulin-like growth factor 2 (IGF 2) and its receptors (IGF 1R and M6-P/IGF 2R).

    Science.gov (United States)

    Pavelić, Kresimir; Kolak, Toni; Kapitanović, Sanja; Radosević, Senka; Spaventi, Sime; Kruslin, Bozo; Pavelić, Jasminka

    2003-11-01

    Insulin-like growth factor 2 (IGF 2) appears to be involved in the progression of many tumours. It binds to at least two different types of receptor: IGF type 1 (IGF 1R) and mannose 6-phosphate/IGF type 2 (M6-P/IGF 2R). Ligand binding to IGF 1R provokes mitogenic and anti-apoptotic effects. M6-P/IGF 2R has a tumour suppressor function--it mediates IGF 2 degradation. Mutation of M6-P/IGF 2R causes both diminished growth suppression and augmented growth stimulation. The aim of this study was to investigate the role of IGF 2 and its receptors (IGF 1R and IGF 2R) in human gastric cancer. The expression of IGF 2 and its receptors was measured in order to analyse the possible correlation between the activity of these genes and cell proliferation in two different gastric tumour types: diffuse and intestinal. The effect of IGF 1 receptor blockage on cell proliferation and anchorage-independent cell growth was also examined. Increased expression of IGF 2 and IGF 1R genes (at the mRNA and protein level) was found in gastric cancer when compared with non-tumour tissue. Furthermore, there was a significant difference between IGF 2 expression in the more aggressive diffuse type and that in the intestinal type of gastric cancer. Moreover, the IGF 2 peptide level in the culture media obtained from the diffuse type of cancer cells was significantly higher when compared with the intestinal type. The level of IGF 2 peptide in the conditioned media strongly correlated with [3H]thymidine incorporation and cell proliferation. On the contrary, IGF 2R mRNA expression was much higher in the intestinal type of cancer than in the diffuse type. In addition, IGF 2R protein expression was substantially lower with progression of the diffuse cancer type to a higher stage. The alphaIR3 monoclonal antibody strongly inhibited [3H]thymidine incorporation and decreased the number of colonies in soft agar of cells overexpressing IGF 2. These findings suggest that members of the IGF family are involved

  20. Genomewide meta-analysis identifies loci associated with IGF-I and IGFBP-3 levels with impact on age-related traits

    DEFF Research Database (Denmark)

    Teumer, Alexander; Qi, Qibin; Nethander, Maria

    2016-01-01

    The growth hormone/insulin-like growth factor (IGF) axis can be manipulated in animal models to promote longevity, and IGF-related proteins including IGF-I and IGF-binding protein-3 (IGFBP-3) have also been implicated in risk of human diseases including cardiovascular diseases, diabetes, and cancer......-associated variant rs2153960 (FOXO3) was observed to be a genomewide significant SNP for IGF-I concentrations. Bioinformatics analysis suggested enrichment of putative regulatory elements among these IGF-I- and IGFBP-3-associated loci, particularly of rs646776 at CELSR2. In conclusion, this study identified several...

  1. Expression of IGF-I and Protein Degradation Markers During Hindlimb Unloading and Growth Hormone Administration in Rats

    Science.gov (United States)

    Leinsoo, T. A.; Turtikova, O. V.; Shenkman, B. S.

    2013-02-01

    It is known that hindlimb unloading or spaceflight produce atrophy and a number of phenotypic alterations in skeletal muscles. Many of these processes are triggered by the axis growth hormone/insulin-like growth factor I. However growth hormone (GH) and insulin-like growth factor I (IGF-I) expression relationship in rodent models of gravitational unloading is weakly investigated. We supposed the IGF-I is involved in regulation of protein turnover. In this study we examined the IGF-I expression by RT-PCR assay in the rat soleus, tibialis anterior and liver after 3 day of hindlimb suspension with growth hormone administration. Simultaneously were studied expression levels of MuRF-1 and MAFbx/atrogin as a key markers of intracellular proteolysis. We demonstrated that GH administration did not prevent IGF-I expression decreasing under the conditions of simulated weightlessness. It was concluded there are separate mechanisms of action of GH and IGF-I on protein metabolism in skeletal muscles. Gravitational unloading activate proteolysis independently of growth hormone activity.

  2. The ratio between serum levels of insulin-like growth factor (IGF)-I and the IGF binding proteins (IGFBP-1, 2 and 3) decreases with age in healthy adults and is increased in acromegalic patients

    DEFF Research Database (Denmark)

    Juul, A; Main, K; Blum, W F

    1994-01-01

    Several in-vitro studies have suggested that the biological actions of IGF-I can be modified by the presence of specific IGF binding proteins. In man, the 24-hour serum levels of IGF-I and IGFBP-3 remain constant, but short-term changes in the IGF-I/IGFBP-3 ratio have been described following GH...... administration. Serum levels of IGF-I and IGFBP-3 decrease with age in normal adults and are elevated in active acromegaly due to excessive GH secretion. However, the individual ratios between serum levels of IGF-I and IGFBP-3 in acromegalic and healthy adults have not been described previously....

  3. Synaptic Activity and Muscle Contraction Increases PDK1 and PKCβI Phosphorylation in the Presynaptic Membrane of the Neuromuscular Junction

    Directory of Open Access Journals (Sweden)

    Erica Hurtado

    2017-08-01

    Full Text Available Conventional protein kinase C βI (cPKCβI is a conventional protein kinase C (PKC isoform directly involved in the regulation of neurotransmitter release in the neuromuscular junction (NMJ. It is located exclusively at the nerve terminal and both synaptic activity and muscle contraction modulate its protein levels and phosphorylation. cPKCβI molecular maturation includes a series of phosphorylation steps, the first of which is mediated by phosphoinositide-dependent kinase 1 (PDK1. Here, we sought to localize PDK1 in the NMJ and investigate the hypothesis that synaptic activity and muscle contraction regulate in parallel PDK1 and cPKCβI phosphorylation in the membrane fraction. To differentiate the presynaptic and postsynaptic activities, we abolished muscle contraction with μ-conotoxin GIIIB (μ-CgTx-GIIIB in some experiments before stimulation of the phrenic nerve (1 Hz, 30 min. Then, we analyzed total and membrane/cytosol fractions of skeletal muscle by Western blotting. Results showed that PDK1 is located exclusively in the nerve terminal of the NMJ. After nerve stimulation with and without coincident muscle contraction, total PDK1 and phosphorylated PDK1 (pPDK1 protein levels remained unaltered. However, synaptic activity specifically enhanced phosphorylation of PDK1 in the membrane, an important subcellular location for PDK1 function. This increase in pPDK1 coincides with a significant increase in the phosphorylation of its substrate cPKCβI also in the membrane fraction. Moreover, muscle contraction maintains PDK1 and pPDK1 but increases cPKCβI protein levels and its phosphorylation. Thus, even though PDK1 activity is maintained, pcPKCβI levels increase in concordance with total cPKCβI. Together, these results indicate that neuromuscular activity could induce the membrane targeting of pPDK1 in the nerve terminal of the NMJ to promote the phosphorylation of the cPKCβI, which is involved in ACh release.

  4. Synaptic Activity and Muscle Contraction Increases PDK1 and PKCβI Phosphorylation in the Presynaptic Membrane of the Neuromuscular Junction.

    Science.gov (United States)

    Hurtado, Erica; Cilleros, Víctor; Just, Laia; Simó, Anna; Nadal, Laura; Tomàs, Marta; Garcia, Neus; Lanuza, Maria A; Tomàs, Josep

    2017-01-01

    Conventional protein kinase C βI (cPKCβI) is a conventional protein kinase C (PKC) isoform directly involved in the regulation of neurotransmitter release in the neuromuscular junction (NMJ). It is located exclusively at the nerve terminal and both synaptic activity and muscle contraction modulate its protein levels and phosphorylation. cPKCβI molecular maturation includes a series of phosphorylation steps, the first of which is mediated by phosphoinositide-dependent kinase 1 (PDK1). Here, we sought to localize PDK1 in the NMJ and investigate the hypothesis that synaptic activity and muscle contraction regulate in parallel PDK1 and cPKCβI phosphorylation in the membrane fraction. To differentiate the presynaptic and postsynaptic activities, we abolished muscle contraction with μ-conotoxin GIIIB (μ-CgTx-GIIIB) in some experiments before stimulation of the phrenic nerve (1 Hz, 30 min). Then, we analyzed total and membrane/cytosol fractions of skeletal muscle by Western blotting. Results showed that PDK1 is located exclusively in the nerve terminal of the NMJ. After nerve stimulation with and without coincident muscle contraction, total PDK1 and phosphorylated PDK1 (pPDK1) protein levels remained unaltered. However, synaptic activity specifically enhanced phosphorylation of PDK1 in the membrane, an important subcellular location for PDK1 function. This increase in pPDK1 coincides with a significant increase in the phosphorylation of its substrate cPKCβI also in the membrane fraction. Moreover, muscle contraction maintains PDK1 and pPDK1 but increases cPKCβI protein levels and its phosphorylation. Thus, even though PDK1 activity is maintained, pcPKCβI levels increase in concordance with total cPKCβI. Together, these results indicate that neuromuscular activity could induce the membrane targeting of pPDK1 in the nerve terminal of the NMJ to promote the phosphorylation of the cPKCβI, which is involved in ACh release.

  5. Positive associations between serum levels of IGF-I and subcutaneous fat depots in young men. The Odense Androgen Study

    DEFF Research Database (Denmark)

    Andersen, M; Brixen, K; Hagen, C

    2012-01-01

    Serum levels of IGF-I are of growing interest due to the associations with morbidity and mortality. Despite markedly suppressed GH secretion, total IGF-I levels are often within normal range in obese adults.......Serum levels of IGF-I are of growing interest due to the associations with morbidity and mortality. Despite markedly suppressed GH secretion, total IGF-I levels are often within normal range in obese adults....

  6. Genetic influence on the associations between IGF-I and glucose metabolism in a cohort of elderly twins

    DEFF Research Database (Denmark)

    Jensen, Rikke Beck; Thankamony, Ajay; Holst, Klaus K.

    2018-01-01

    OBJECTIVE: IGF-I may be a marker of later metabolic and cardiovascular disease. The interactions between IGF-I and glucose metabolism are multifactorial, and there is potential confounding from several secondary effects. In this study, we examined the interaction between IGF-I and glucose...... metabolism in a large cohort of clinically well-characterized elderly twins. DESIGN: A total of 303 twin pairs of the same gender (606 twins) were included in the study; 125 monozygotic and 178 dizygotic twin pairs. METHODS: A clinical examination including a standard oral glucose tolerance test (OGTT.......11). In a multiple regression analysis (adjusting for age, gender and twin status), there was a negative association between IGF-I and insulin sensitivity (B: -0.13, SE 0.03, P cohort of 606 twins. The associations between IGF...

  7. Effects of High Intensity Interval Training on Plasma Levels of GH and IGF-I

    Directory of Open Access Journals (Sweden)

    Seyyed Mahmoud Hejazi

    2017-04-01

    Full Text Available Introduction: It is well-recognized that exercise has a significant impact on the GH/IGF system but less is known about the effects of HIIT on this axis. Aim of the present study was to evaluate the effect of ten weeks of HIIT on plasma levels of GH and IGF-I in healthy men. Methods: Twenty young men (age 23.34 ± 2.56 weight 72.47 ± 12.01 height 174.10 ± 5.75 recruited and randomly assigned into control (n=10 and HIIT (n=12 groups. HIIT protocol was started with 4 cycles. Then, every two weeks one cycle was added to the previous ones. Finally, it was to 8 cycles/ session in tenth weeks that lasted 16 minutes. Blood samples were collected prior to and after HIIT program for all subjects and IGF-I and GH levels were measured. Result: HIIT subjects showed a significant increase in IGF-I (P=0.002, F=12.38. However, no significant change was shown in GH levels (P=0.716, F=0.62. Discussion and conclusion: Our findings indicate that the HIIT caused increase in circulating levels of IGF-I independently from GH levels. Both hormones may contribute to positive effects of anabolic conditions.

  8. Akt phosphorylation is essential for nuclear translocation and retention in NGF-stimulated PC12 cells

    International Nuclear Information System (INIS)

    Truong Le Xuan Nguyen; Choi, Joung Woo; Lee, Sang Bae; Ye, Keqiang; Woo, Soo-Dong; Lee, Kyung-Hoon; Ahn, Jee-Yin

    2006-01-01

    Nerve growth factor (NGF) elicits Akt translocation into the nucleus, where it phosphorylates nuclear targets. Here, we describe that Akt phosphorylation can promote the nuclear translocation of Akt and is necessary for its nuclear retention. Overexpression of Akt-K179A, T308A, S473A-mutant failed to show either nuclear translocation or nuclear Akt phosphorylation, whereas expression of wild-type counterpart elicited profound Akt phosphorylation and induced nuclear translocation under NGF stimulation. Employing the PI3K inhibitor and a variety of mutants PI3K, we showed that nuclear translocation of Akt was mediated by activation of PI3K, and Akt phosphorylation status in the nucleus required PI3K activity. Thus the activity of PI3K might contribute to the nuclear translocation of Akt, and that Akt phosphorylation is essential for its nuclear retention under NGF stimulation conditions

  9. Insulin-like growth factor I (IGF-1) Ec/Mechano Growth factor--a splice variant of IGF-1 within the growth plate.

    Science.gov (United States)

    Schlegel, Werner; Raimann, Adalbert; Halbauer, Daniel; Scharmer, Daniela; Sagmeister, Susanne; Wessner, Barbara; Helmreich, Magdalena; Haeusler, Gabriele; Egerbacher, Monika

    2013-01-01

    Human insulin-like growth factor 1 Ec (IGF-1Ec), also called mechano growth factor (MGF), is a splice variant of insulin-like growth factor 1 (IGF-1), which has been shown in vitro as well as in vivo to induce growth and hypertrophy in mechanically stimulated or damaged muscle. Growth, hypertrophy and responses to mechanical stimulation are important reactions of cartilaginous tissues, especially those in growth plates. Therefore, we wanted to ascertain if MGF is expressed in growth plate cartilage and if it influences proliferation of chondrocytes, as it does in musculoskeletal tissues. MGF expression was analyzed in growth plate and control tissue samples from piglets aged 3 to 6 weeks. Furthermore, growth plate chondrocyte cell culture was used to evaluate the effects of the MGF peptide on proliferation. We showed that MGF is expressed in considerable amounts in the tissues evaluated. We found the MGF peptide to be primarily located in the cytoplasm, and in some instances, it was also found in the nucleus of the cells. Addition of MGF peptides was not associated with growth plate chondrocyte proliferation.

  10. Changes of Cerebral and/or Peripheral Adenosine A₁ Receptor and IGF-I Concentrations under Extended Sleep Duration in Rats.

    Science.gov (United States)

    Chennaoui, Mounir; Arnal, Pierrick J; Dorey, Rodolphe; Sauvet, Fabien; Ciret, Sylvain; Gallopin, Thierry; Leger, Damien; Drogou, Catherine; Gomez-Merino, Danielle

    2017-11-17

    Extended sleep improves sustained attention and reduces sleep pressure in humans. Downregulation of adenosine A₁ receptor (A₁R) and modulation of the neurotrophic factor insulin growth factor-1 (IGF-I) in brain structures controlling attentional capacities could be involved. In the frontal cortex and hippocampus of rats, we measured adenosine A₁R and IGF-I protein concentrations after photoperiod-induced sleep extension. Two groups of twelve rats were adapted over 14 days to a habitual (CON) 12:12 light-dark (LD) schedule and an extended (EXT) 16:8 LD schedule. IGF-I content was also measured in plasma, liver, and skeletal muscle. In EXT, compared to CON rats, A₁R content in the frontal cortex was significantly lower ( p IGF-I content was higher ( p IGF-I content in plasma and muscle was higher ( p IGF-I levels. This photoperiod induced an anabolic profile with increased weight gain and circulating and muscular IGF-I levels. An extension of sleep duration might favor cerebral and peripheral anabolism, which may help attentional and physical capacities.

  11. Study on changes of serum leptin, IGF-I and IL-2 levels in elderly subjects with osteoporosis

    International Nuclear Information System (INIS)

    Sun Zihan; Luo Nanping; Niu Aijun; Qi Falian

    2006-01-01

    Objective: To investigate the changes of serum leptin, IGF-I and IL-2 levels in elderly subjects with osteoporosis. Methods: Serum leptin, IGF-I, IL-2 levels (with RIA), total cholesterol contents (with biochemical method) and bone mineral density (BMD) were examined in 65 aged patients with osteoporosis. Results: The serum leptin levels in subjects with osteoporosis were significantly higher than controls (P<0.01). The serum IGF-I and IL-2 levels in subjects with osteoporosis were significantly lower than those in controls (P<0.05, P<0.01). The BMD was positively correlated with the IGF-I levels and negatively correlated with leptin level. Conclusion: Derangement of leptin and IGF-I, IL-2 metabolism is one of the major causes of decreased bone mass and bone formation elderly subjects with osteoporosis. Measurement of serum levels of these parameters is of diagnostic help. (authors)

  12. Human GH Receptor-IGF-1 Receptor Interaction: Implications for GH Signaling

    Science.gov (United States)

    Gan, Yujun; Buckels, Ashiya; Liu, Ying; Zhang, Yue; Paterson, Andrew J.; Jiang, Jing; Zinn, Kurt R.

    2014-01-01

    GH signaling yields multiple anabolic and metabolic effects. GH binds the transmembrane GH receptor (GHR) to activate the intracellular GHR-associated tyrosine kinase, Janus kinase 2 (JAK2), and downstream signals, including signal transducer and activator of transcription 5 (STAT5) activation and IGF-1 gene expression. Some GH effects are partly mediated by GH-induced IGF-1 via IGF-1 receptor (IGF-1R), a tyrosine kinase receptor. We previously demonstrated in non-human cells that GH causes formation of a GHR-JAK2-IGF-1R complex and that presence of IGF-1R (even without IGF-1 binding) augments proximal GH signaling. In this study, we use human LNCaP prostate cancer cells as a model system to further study the IGF-1R's role in GH signaling. GH promoted JAK2 and GHR tyrosine phosphorylation and STAT5 activation in LNCaP cells. By coimmunoprecipitation and a new split luciferase complementation assay, we find that GH augments GHR/IGF-1R complex formation, which is inhibited by a Fab of an antagonistic anti-GHR monoclonal antibody. Short hairpin RNA-mediated IGF-1R silencing in LNCaP cells reduced GH-induced GHR, JAK2, and STAT5 phosphorylation. Similarly, a soluble IGF-1R extracellular domain fragment (sol IGF-1R) interacts with GHR in response to GH and blunts GH signaling. Sol IGF-1R also markedly inhibits GH-induced IGF-1 gene expression in both LNCaP cells and mouse primary osteoblast cells. On the basis of these and other findings, we propose a model in which IGF-1R augments GH signaling by allowing a putative IGF-1R-associated molecule that regulates GH signaling to access the activated GHR/JAK2 complex and envision sol IGF-1R as a dominant-negative inhibitor of this IGF-1R-mediated augmentation. Physiological implications of this new model are discussed. PMID:25211187

  13. Loss of neutrophil polarization in colon carcinoma liver metastases of mice with an inducible, liver-specific IGF-I deficiency.

    Science.gov (United States)

    Rayes, Roni F; Milette, Simon; Fernandez, Maria Celia; Ham, Boram; Wang, Ni; Bourdeau, France; Perrino, Stephanie; Yakar, Shoshana; Brodt, Pnina

    2018-03-20

    The growth of cancer metastases in the liver depends on a permissive interaction with the hepatic microenvironment and neutrophils can contribute to this interaction, either positively or negatively, depending on their phenotype. Here we investigated the role of IGF-I in the control of the tumor microenvironment in the liver, using mice with a conditional, liver-specific, IGF-I deficiency (iLID) induced by a single tamoxifen injection. In mice that had a sustained (3 weeks) IGF-I deficiency prior to the intrasplenic/portal inoculation of colon carcinoma MC-38 cells, we observed an increase in neutrophil accumulation in the liver relative to controls. However, unlike controls, these neutrophils did not acquire the (anti-inflammatory) tumor-promoting phenotype, as evidenced by retention of high ICAM-1 expression and nitric oxide production and low CXCR4, CCL5, and VEGF expression and arginase production, all characteristic of the (pro-inflammatory) phenotype. This coincided with an increase in apoptotic tumor cells and reduced metastasis. Neutrophils isolated from these mice also had reduced IGF-IR expression levels. These changes were not observed in iLID mice with a short-term (2 days) IGF-I depletion, despite a 70% reduction in their circulating IGF-I levels, indicating that a sustained IGF-I deficiency was necessary to alter the neutrophil phenotype. Similar results were obtained with the highly metastatic Lewis lung carcinoma subline H-59 cells and in mice injected with an IGF-Trap that blocks IGF-IR signaling by reducing ligand bioavailability. Our results implicate the IGF axis in neutrophil polarization and the induction of a pro-metastatic microenvironment in the liver.

  14. Leptin does not mediate short-term fasting-induced changes in growth hormone pulsatility but increases IGF-I in leptin deficiency states.

    Science.gov (United States)

    Chan, Jean L; Williams, Catherine J; Raciti, Patricia; Blakeman, Jennifer; Kelesidis, Theodore; Kelesidis, Iosif; Johnson, Michael L; Thorner, Michael O; Mantzoros, Christos S

    2008-07-01

    States of acute and chronic energy deficit are characterized by increased GH secretion and decreased IGF-I levels. The objective of the study was to determine whether changes in levels of leptin, a key mediator of the adaptation to starvation, regulate the GH-IGF system during energy deficit. We studied 14 healthy normal-weight men and women during three conditions: baseline fed and 72-h fasting (to induce hypoleptinemia) with administration of placebo or recombinant methionyl human leptin (r-metHuLeptin) (to reverse the fasting associated hypoleptinemia). We also studied eight normal-weight women with exercise-induced chronic energy deficit and hypothalamic amenorrhea at baseline and during 2-3 months of r-metHuLeptin treatment. GH pulsatility, IGF levels, IGF and GH binding protein (GHBP) levels were measured. During short-term energy deficit, measures of GH pulsatility and disorderliness and levels of IGF binding protein (IGFBP)-1 increased, whereas leptin, insulin, IGF-I (total and free), IGFBP-4, IGFBP-6, and GHBP decreased; r-metHuLeptin administration blunted the starvation-associated decrease of IGF-I. In chronic energy deficit, total and free IGF-I, IGFBP-6, and GHBP levels were lower, compared with euleptinemic controls; r-metHuLeptin administration had no major effect on GH pulsatility after 2 wk but increased total IGF-I levels and tended to increase free IGF-I and IGFBP-3 after 1 month. The GH/IGF system changes associated with energy deficit are largely independent of leptin deficiency. During acute energy deficit, r-metHuLeptin administration in replacement doses blunts the starvation-induced decrease of IGF-I, but during chronic energy deficit, r-metHuLeptin administration increases IGF-I and tends to increase free IGF-I and IGFBP-3.

  15. Negative Role of RIG-I Serine 8 Phosphorylation in the Regulatin of Interferon-beta Production

    Energy Technology Data Exchange (ETDEWEB)

    E Nistal-Villan; M Gack; G Martinez-Delgado; N Maharaj; K Inn; H Yang; R Wang; A Aggarwal; J Jung; A Garcia-Sastre

    2011-12-31

    RIG-I (retinoic acid-inducible gene I) and TRIM25 (tripartite motif protein 25) have emerged as key regulatory factors to induce interferon (IFN)-mediated innate immune responses to limit viral replication. Upon recognition of viral RNA, TRIM25 E3 ligase binds the first caspase recruitment domain (CARD) of RIG-I and subsequently induces lysine 172 ubiquitination of the second CARD of RIG-I, which is essential for the interaction with downstream MAVS/IPS-1/CARDIF/VISA and, thereby, IFN-beta mRNA production. Although ubiquitination has emerged as a major factor involved in RIG-I activation, the potential contribution of other post-translational modifications, such as phosphorylation, to the regulation of RIG-I activity has not been addressed. Here, we report the identification of serine 8 phosphorylation at the first CARD of RIG-I as a negative regulatory mechanism of RIG-I-mediated IFN-beta production. Immunoblot analysis with a phosphospecific antibody showed that RIG-I serine 8 phosphorylation steady-state levels were decreased upon stimulation of cells with IFN-beta or virus infection. Substitution of serine 8 in the CARD RIG-I functional domain with phosphomimetic aspartate or glutamate results in decreased TRIM25 binding, RIG-I ubiquitination, MAVS binding, and downstream signaling. Finally, sequence comparison reveals that only primate species carry serine 8, whereas other animal species carry an asparagine, indicating that serine 8 phosphorylation may represent a primate-specific regulation of RIG-I activation. Collectively, these data suggest that the phosphorylation of RIG-I serine 8 operates as a negative switch of RIG-I activation by suppressing TRIM25 interaction, further underscoring the importance of RIG-I and TRIM25 connection in type I IFN signal transduction.

  16. Changes in IGF-I and its Binding Proteins Are Associated with Diabetes in Older Adults

    Science.gov (United States)

    Aneke, Chino S.; Parrinello, Christina M.; Rajpathak, Swapnil N.; Rohan, Thomas E.; Strotmeyer, Elsa S.; Kritchevsky, Stephen B.; Psaty, Bruce M.; Bůžková, Petra; Kizer, Jorge R.; Newman, Anne B.; Strickler, Howard D.; Kaplan, Robert C.

    2015-01-01

    Objectives Little is known about long-term changes in insulin-like growth Factor (IGF) proteins and glycemic status. We hypothesized that changes in IGF proteins are exaggerated in participants with type 2 diabetes or worsening glycemia versus those that remain normoglycemic over a 9-year follow-up period. Design Retrospective analysis of cohort study. Setting Participants were recruited from four States: North Carolina, California, Maryland and Pennsylvania. Participants 897 participants enrolled in CHS All Stars, a cohort study of community dwelling adults aged ≥65 years. Measurements Plasma IGF-I, IGFBP-1, and IGFBP-3 levels were assessed and ADA cut-points for IGT, IFG, and diabetes were used to classify participants at baseline (1996–1997) and follow-up (2005–2006). Results At baseline, mean age was 76.3 years (± 3.6) and 18.5% had diabetes. Individuals with IFG alone and IGT+IFG had the highest levels of IGF-I and lowest levels of IGFBP-1, compared to individuals with normoglycemia or diabetes. The greatest percent change in IGF levels occurred in those who had diabetes at baseline (9-year changes: −9.3% for IGF-I, 59.7% for IGFBP-1, −13.4% for IGFBP-3); the smallest in individuals who remained normoglycemic at follow-up (9-year changes: −3.7% for IGF-I, 25.6% for IGFBP-1, −6.4% for IGFBP-3); and intermediate changes in those who were normoglycemic but developed IFG at follow-up. Conclusion Our results demonstrate that degrees of glycemic impairment are associated with varying levels of changes in IGF proteins. The exaggerated changes observed in the diabetes group have been previously shown to be associated with heart failure, cancer and non-cancer mortality. PMID:25989565

  17. Validation of serum IGF-I as a biomarker to monitor the bioactivity of exogenous growth hormone agonists and antagonists in rabbits

    Science.gov (United States)

    Bielohuby, Maximilian; Zarkesh-Esfahani, Sayyed Hamid; Manolopoulou, Jenny; Wirthgen, Elisa; Walpurgis, Katja; Toghiany Khorasgani, Mohaddeseh; Aghili, Zahra Sadat; Wilkinson, Ian Robert; Hoeflich, Andreas; Thevis, Mario; Ross, Richard J.; Bidlingmaier, Martin

    2014-01-01

    The development of new growth hormone (GH) agonists and growth hormone antagonists (GHAs) requires animal models for pre-clinical testing. Ideally, the effects of treatment are monitored using the same pharmacodynamic marker that is later used in clinical practice. However, intact rodents are of limited value for this purpose because serum IGF-I, the most sensitive pharmacodynamic marker for the action of GH in humans, shows no response to treatment with recombinant human GH and there is little evidence for the effects of GHAs, except when administered at very high doses or when overexpressed. As an alternative, more suitable model, we explored pharmacodynamic markers of GH action in intact rabbits. We performed the first validation of an IGF-I assay for the analysis of rabbit serum and tested precision, sensitivity, linearity and recovery using an automated human IGF-I assay (IDS-iSYS). Furthermore, IGF-I was measured in rabbits of different strains, age groups and sexes, and we monitored IGF-I response to treatment with recombinant human GH or the GHA Pegvisomant. For a subset of samples, we used LC-MS/MS to measure IGF-I, and quantitative western ligand blot to analyze IGF-binding proteins (IGFBPs). Although recovery of recombinant rabbit IGF-I was only 50% in the human IGF-I assay, our results show that the sensitivity, precision (1.7–3.3% coefficient of variation) and linearity (90.4–105.6%) were excellent in rabbit samples. As expected, sex, age and genetic background were major determinants of IGF-I concentration in rabbits. IGF-I and IGFBP-2 levels increased after single and multiple injections of recombinant human GH (IGF-I: 286±22 versus 434±26 ng/ml; PIGF-I levels from the fourth injection onwards (PIGF-I immunoassay can be used in rabbits. Similar to rodents, rabbits display variations in IGF-I depending on sex, age and genetic background. Unlike in rodents, the IGF-I response to treatment with recombinant human GH or a GHA closely mimics the

  18. Recovery of whisking function promoted by manual stimulation of the vibrissal muscles after facial nerve injury requires insulin-like growth factor 1 (IGF-1).

    Science.gov (United States)

    Kiryakova, S; Söhnchen, J; Grosheva, M; Schuetz, U; Marinova, Ts; Dzhupanova, R; Sinis, N; Hübbers, C U; Skouras, E; Ankerne, J; Fries, J W U; Irintchev, A; Dunlop, S A; Angelov, D N

    2010-04-01

    Recently, we showed that manual stimulation (MS) of denervated vibrissal muscles enhanced functional recovery following facial nerve cut and suture (FFA) by reducing poly-innervation at the neuro-muscular junctions (NMJ). Although the cellular correlates of poly-innervation are established, with terminal Schwann cells (TSC) processes attracting axon sprouts to "bridge" adjacent NMJ, molecular correlates are poorly understood. Since quantitative RT-PCR revealed a rapid increase of IGF-1 mRNA in denervated muscles, we examined the effect of daily MS for 2 months after FFA in IGF-1(+/-) heterozygous mice; controls were wild-type (WT) littermates including intact animals. We quantified vibrissal motor performance and the percentage of NMJ bridged by S100-positive TSC. There were no differences between intact WT and IGF-1(+/-) mice for vibrissal whisking amplitude (48 degrees and 49 degrees ) or the percentage of bridged NMJ (0%). After FFA and handling alone (i.e. no MS) in WT animals, vibrissal whisking amplitude was reduced (60% lower than intact) and the percentage of bridged NMJ increased (42% more than intact). MS improved both the amplitude of vibrissal whisking (not significantly different from intact) and the percentage of bridged NMJ (12% more than intact). After FFA and handling in IGF-1(+/-) mice, the pattern was similar (whisking amplitude 57% lower than intact; proportion of bridged NMJ 42% more than intact). However, MS did not improve outcome (whisking amplitude 47% lower than intact; proportion of bridged NMJ 40% more than intact). We conclude that IGF-I is required to mediate the effects of MS on target muscle reinnervation and recovery of whisking function. Copyright 2010 Elsevier Inc. All rights reserved.

  19. Tendon protein synthesis rate in classic Ehlers-Danlos patients can be stimulated with insulin-like growth factor-I

    DEFF Research Database (Denmark)

    Nielsen, Rie Harboe; Holm, Lars; Jensen, Jacob Kildevang

    2014-01-01

    tissue protein turnover is unknown. We investigated whether cEDS affected the protein synthesis rate in skin and tendon, and whether this could be stimulated in tendon tissue with insulin-like growth factor-I (IGF-I). Five patients with cEDS and 10 healthy, matched controls (CTRL) were included. One...... patellar tendon of each participant was injected with 0.1 ml IGF-I (Increlex, Ipsen, 10 mg/ml) and the contralateral tendon with 0.1 ml isotonic saline as control. The injections were performed at both 24 and 6 h prior to tissue sampling. The fractional synthesis rate (FSR) of proteins in skin and tendon.......002 (cEDS) and 0.007 ± 0.002 (CTRL); tendon: 0.008 ± 0.001 (cEDS) and 0.009 ± 0.002 (CTRL) %/h, mean ± SE]. IGF-I injections significantly increased FSR values in cEDS patients but not in controls (delta values: cEDS 0.007 ± 0.002, CTRL 0.001 ± 0.001%/h). In conclusion, baseline protein synthesis rates...

  20. GH/IGF-I axis and matrix adaptation of the musculotendinous tissue to exercise in humans

    DEFF Research Database (Denmark)

    Heinemeier, K M; Mackey, Abigail; Doessing, S

    2012-01-01

    cells (satellite cells), as increased satellite cell numbers are found in human muscle with increased GH/IGF-I levels, despite no change in myofibrillar protein synthesis. Although advanced age is associated with both a reduction in the GH/IGF-I axis activity, and in skeletal muscle mass (sarcopenia...

  1. Cartilage formation measured by a novel PIINP assay suggests that IGF-I does not stimulate but maintains cartilage formation ex vivo

    DEFF Research Database (Denmark)

    Madsen, S H; Sondergaard, B C; Jensen, Anne-Christine Bay

    2009-01-01

    explants were cultured in Dulbecco's modified Eagle's medium (DMEM):F12 in the presence of 0, 0.01, 0.1, 1, 10, or 100 ng/mL of IGF-I. The viability of the chondrocytes was measured by the colorimetric Alamar blue assay. Collagen formation was assessed from the conditioned medium by the PIINP assay...

  2. Long-pulse gastric electrical stimulation protects interstitial cells of Cajal in diabetic rats via IGF-1 signaling pathway.

    Science.gov (United States)

    Li, Hai; Chen, Yan; Liu, Shi; Hou, Xiao-Hua

    2016-06-21

    To investigate the effects of different parameters of gastric electrical stimulation (GES) on interstitial cells of Cajal (ICCs) and changes in the insulin-like growth factor 1 (IGF-1) signal pathway in streptozotocin-induced diabetic rats. Male rats were randomized into control, diabetic (DM), diabetic with sham GES (DM + SGES), diabetic with GES1 (5.5 cpm, 100 ms, 4 mA) (DM + GES1), diabetic with GES2 (5.5 cpm, 300 ms, 4 mA) (DM + GES2) and diabetic with GES3 (5.5 cpm, 550 ms, 2 mA) (DM + GES3) groups. The expression levels of c-kit, M-SCF and IGF-1 receptors were evaluated in the gastric antrum using Western blot analysis. The distribution of ICCs was observed using immunolabeling for c-kit, while smooth muscle cells and IGF-1 receptors were identified using α-SMA and IGF-1R antibodies. Serum level of IGF-1 was tested using enzyme-linked immunosorbent assay. Gastric emptying was delayed in the DM group but improved in all GES groups, especially in the GES2 group. The expression levels of c-kit, M-SCF and IGF-1R were decreased in the DM group but increased in all GES groups. More ICCs (c-kit(+)) and smooth muscle cells (α-SMA(+)/IGF-1R(+)) were observed in all GES groups than in the DM group. The average level of IGF-1 in the DM group was markedly decreased, but it was up-regulated in all GES groups, especially in the GES2 group. The results suggest that long-pulse GES promotes the regeneration of ICCs. The IGF-1 signaling pathway might be involved in the mechanism underlying this process, which results in improved gastric emptying.

  3. IGF-I en la homeostasia cerebral: implicaciones patológicas

    Directory of Open Access Journals (Sweden)

    Ignacio Torres

    2005-03-01

    Full Text Available El factor de crecimiento de la familia de la insulina tipo I (IGF-I es una proteína sérica especialmente abundante fabricada principalmente en el hígado; su producción está regulada por la hormona de crecimiento (GH hipofisario.

  4. Kinase inhibitors of the IGF-1R as a potential therapeutic agent for rheumatoid arthritis.

    Science.gov (United States)

    Tsushima, Hiroshi; Morimoto, Shinji; Fujishiro, Maki; Yoshida, Yuko; Hayakawa, Kunihiro; Hirai, Takuya; Miyashita, Tomoko; Ikeda, Keigo; Yamaji, Ken; Takamori, Kenji; Takasaki, Yoshinari; Sekigawa, Iwao; Tamura, Naoto

    2017-08-01

    We have previously shown that the inhibition of connective tissue growth factor (CTGF) is a potential therapeutic strategy against rheumatoid arthritis (RA). CTGF consists of four distinct modules, including the insulin-like growth factor binding protein (IGFBP). In serum, insulin-like growth factors (IGFs) bind IGFBPs, interact with the IGF-1 receptor (IGF-1 R), and regulate anabolic effects and bone metabolism. We investigated the correlation between IGF-1 and the pathogenesis of RA, and the inhibitory effect on osteoclastogenesis and angiogenesis of the small molecular weight kinase inhibitor of the IGF-1 R, NVP-AEW541, against pathogenesis of RA in vitro. Cell proliferation was evaluated by cell count and immunoblotting. The expression of IGF-1 and IGF-1 R was evaluated by RT-PCR. Osteoclastogenesis was evaluated using tartrate-resistant acid phosphatase staining, a bone resorption assay, and osteoclast-specific enzyme production. Angiogenesis was evaluated by a tube formation assay using human umbilical vein endothelial cells (HUVECs). The proliferation of MH7A cells was found to be inhibited in the presence of NVP-AEW541, and the phosphorylation of extracellular signal-regulated kinase (ERK) and Akt was downregulated in MH7A cells. IGF-1 and IGF-1 R mRNA expression levels were upregulated during formation of M-colony stimulating factor (M-CSF) and receptor activator of NF-κB ligand (RANKL)-mediated osteoclast formation. Moreover, osteoclastogenesis was suppressed in the presence of NVP-AEW541. The formation of the tubular network was enhanced by IGF-1, and this effect was neutralized by NVP-ARE541. Our findings suggest that NVP-AEW541 may be utilized as a potential therapeutic agent in the treatment of RA.

  5. A polymorphism in the gene for IGF-I: functional properties and risk for type 2 diabetes and myocardial infarction

    NARCIS (Netherlands)

    N. Vaessen (Norbert); J.C.M. Witteman (Jacqueline); L. Testers; S.W.J. Lamberts (Steven); B.A. Oostra (Ben); H.A.P. Pols (Huib); C.M. van Duijn (Cornelia); J.A.M.J.L. Janssen (Joseph); P. Heutink (Peter); A. Hofman (Albert)

    2001-01-01

    textabstractEvidence is accumulating that low levels of IGF-I play a role in the pathogenesis of type 2 diabetes and cardiovascular diseases. We examined the role of a genetic polymorphism in the promoter region of the IGF-I gene in relation to circulating IGF-I levels and growth measured as body

  6. Insulin-like growth factor I (IGF-1 Ec/Mechano Growth factor--a splice variant of IGF-1 within the growth plate.

    Directory of Open Access Journals (Sweden)

    Werner Schlegel

    Full Text Available Human insulin-like growth factor 1 Ec (IGF-1Ec, also called mechano growth factor (MGF, is a splice variant of insulin-like growth factor 1 (IGF-1, which has been shown in vitro as well as in vivo to induce growth and hypertrophy in mechanically stimulated or damaged muscle. Growth, hypertrophy and responses to mechanical stimulation are important reactions of cartilaginous tissues, especially those in growth plates. Therefore, we wanted to ascertain if MGF is expressed in growth plate cartilage and if it influences proliferation of chondrocytes, as it does in musculoskeletal tissues. MGF expression was analyzed in growth plate and control tissue samples from piglets aged 3 to 6 weeks. Furthermore, growth plate chondrocyte cell culture was used to evaluate the effects of the MGF peptide on proliferation. We showed that MGF is expressed in considerable amounts in the tissues evaluated. We found the MGF peptide to be primarily located in the cytoplasm, and in some instances, it was also found in the nucleus of the cells. Addition of MGF peptides was not associated with growth plate chondrocyte proliferation.

  7. Children with severe Osteogenesis imperfecta and short stature present on average with normal IGF-I and IGFBP-3 levels.

    Science.gov (United States)

    Hoyer-Kuhn, Heike; Höbing, Laura; Cassens, Julia; Schoenau, Eckhard; Semler, Oliver

    2016-07-01

    Osteogenesis imperfecta (OI) is characterized by bone fragility and short stature. Data about IGF-I/IGFBP-3 levels are rare in OI. Therefore IGF-I/IGFBP-3 levels in children with different types of OI were investigated. IGF-I and IGFBP-3 levels of 60 children (male n=38) were assessed in a retrospective cross-sectional setting. Height/weight was significant different [height z-score type 3 versus type 4: p=0.0011 and weight (p≤0.0001)] between OI type 3 and 4. Mean IGF-I levels were in the lower normal range (mean±SD level 137.4±109.1 μg/L). Mean IGFBP-3 measurements were in the normal range (mean±SD 3.105±1.175 mg/L). No significant differences between OI type 3 and 4 children have been observed (IGF-I: p=0.0906; IGFBP-3: p=0.2042). Patients with different severities of OI have IGF-I and IGFBP-3 levels in the lower normal range. The type of OI does not significantly influence these growth factors.

  8. Serum from Chronic Hepatitis B Patients Promotes Growth and Proliferation via the IGF-II/IGF-IR/MEK/ERK Signaling Pathway in Hepatocellular Carcinoma Cells.

    Science.gov (United States)

    Ji, Yuanyuan; Wang, Zhidong; Chen, Haiyan; Zhang, Lei; Zhuo, Fei; Yang, Qingqing

    2018-05-09

    Chronic hepatitis B virus (HBV) infection (CHB) plays a central role in the etiology of hepatocellular carcinoma (HCC). Emerging evidence implicates insulin-like growth factor (IGF)-II as a major risk factor for the growth and development of HCC. However, the relationship between HBV infection and IGF-II functions remains to be elucidated. Levels of circulating IGF-II and IGF-I receptor (IGF-IR) in healthy donors (HDs) and CHB patients were tested by ELISA. Human HCC cell lines (HepG-2, SMMC-7721, MHCC97-H) were incubated with serum from HDs and CHB patients at various concentrations for 24, 48, and 72 h. MTT and plate colony formation assays, BrdU ELISA, ELISA, small-interfering RNA (siRNA) transfection, quantitative real-time PCR, and western blot were applied to assess the functional and molecular mechanisms in HCC cell lines. Serum levels of IGF-II and IGF-IR were significantly higher in CHB patients than in HDs. Additionally, serum from CHB patients directly induced cell growth, proliferation, IGF-II secretion, and HDGF-related protein-2 (HRP-2) and nuclear protein 1 (NUPR1) mRNA and protein expression in HCC cells. Moreover, serum from CHB patients increased IGF-II-induced cell growth, proliferation, and HRP-2 and NUPR1 mRNA and protein expression in HCC cells. Blockade of IGF-IR clearly inhibited the above effects. Most importantly, interference with IGF-II function markedly repressed the cell proliferation and HRP-2 and NUPR1 mRNA and protein expression induced by serum from CHB patients. Furthermore, serum from CHB patients induced ERK phosphorylation via IGF-IR, with the MEK inhibitor PD98059 significantly decreasing CHB patient serum-induced IGF-II secretion, cell proliferation, and HRP-2 and NUPR1 mRNA and protein expression. Serum from CHB patients increases cell growth and proliferation and enhances HRP-2 and NUPR1 expression in HCC cells via the IGF-II/IGF-IR/MEK/ERK signaling pathway. These findings help to explain the molecular mechanisms

  9. Over-stimulation of insulin/IGF-1 signaling by western diet may promote diseases of civilization: lessons learnt from laron syndrome

    Directory of Open Access Journals (Sweden)

    Schmitz Gerd

    2011-06-01

    Full Text Available Abstract The insulin/insulin-like growth factor-1 (IGF-1 pathway drives an evolutionarily conserved network that regulates lifespan and longevity. Individuals with Laron syndrome who carry mutations in the growth hormone receptor (GHR gene that lead to severe congenital IGF-1 deficiency with decreased insulin/IGF-1 signaling (IIS exhibit reduced prevalence rates of acne, diabetes and cancer. Western diet with high intake of hyperglycemic carbohydrates and insulinotropic dairy over-stimulates IIS. The reduction of IIS in Laron subjects unmasks the potential role of persistent hyperactive IIS mediated by Western diet in the development of diseases of civilization and offers a rational perspective for dietary adjustments with less insulinotropic diets like the Paleolithic diet.

  10. Over-stimulation of insulin/IGF-1 signaling by western diet may promote diseases of civilization: lessons learnt from laron syndrome.

    Science.gov (United States)

    Melnik, Bodo C; John, Swen Malte; Schmitz, Gerd

    2011-06-24

    The insulin/insulin-like growth factor-1 (IGF-1) pathway drives an evolutionarily conserved network that regulates lifespan and longevity. Individuals with Laron syndrome who carry mutations in the growth hormone receptor (GHR) gene that lead to severe congenital IGF-1 deficiency with decreased insulin/IGF-1 signaling (IIS) exhibit reduced prevalence rates of acne, diabetes and cancer. Western diet with high intake of hyperglycemic carbohydrates and insulinotropic dairy over-stimulates IIS. The reduction of IIS in Laron subjects unmasks the potential role of persistent hyperactive IIS mediated by Western diet in the development of diseases of civilization and offers a rational perspective for dietary adjustments with less insulinotropic diets like the Paleolithic diet.

  11. Evidence That Graves' Ophthalmopathy Immunoglobulins Do Not Directly Activate IGF-1 Receptors.

    Science.gov (United States)

    Marcus-Samuels, Bernice; Krieger, Christine C; Boutin, Alisa; Kahaly, George J; Neumann, Susanne; Gershengorn, Marvin C

    2018-05-01

    Graves' ophthalmopathy (GO) pathogenesis involves thyrotropin (TSH) receptor (TSHR)-stimulating autoantibodies. Whether there are autoantibodies that directly stimulate insulin-like growth factor 1 receptors (IGF-1Rs), stimulating insulin-like growth factor receptor antibodies (IGFRAbs), remains controversial. This study attempted to determine whether there are stimulating IGFRAbs in patients with GO. Immunoglobulins (Igs) were purified from normal volunteers (NV-Igs) and patients with GO (GO-Igs). The effects of TSH, IGF-1, NV-Igs, and GO-Igs on pAKT and pERK1/2, members of pathways used by IGF-1R and TSHR, were compared in orbital fibroblasts from GO patients (GOFs) and U2OS-TSHR cells overexpressing TSHRs, and U2OS cells that express TSHRs at very low endogenous levels. U2OS-TSHR and U2OS cells were used because GOFs are not easily manipulated using molecular techniques such as transfection, and U2OS cells because they express TSHRs at levels that do not measurably stimulate signaling. Thus, comparing U2OS-TSHR and U2OS cells permits specifically distinguishing signaling mediated by the TSHR and IGF-1R. In GOFs, all GO-Igs stimulated pERK1/2 formation and 69% stimulated pAKT. In U2OS-TSHR cells, 15% of NV-IGs and 83% of GO-Igs stimulated increases in pERK1/2, whereas all NV-Igs and GO-Igs stimulated increases in pAKT. In U2OS cells, 70% of GO-Igs stimulated small increases in pAKT. Knockdown of IGF-1R caused a 65 ± 6.3% decrease in IGF-1-stimulated pAKT but had no effect on GO-Igs stimulation of pAKT. Thus, GO-Igs contain factor(s) that stimulate pAKT formation. However, this factor(s) does not directly activate IGF-1R. Based on the findings analyzing these two signaling pathways, it is concluded there is no evidence of stimulating IGFRAbs in GO patients.

  12. Effects of an endurance cycling competition on resting serum insulin-like growth factor I (IGF-I) and its binding proteins IGFBP-1 and IGFBP-3

    Science.gov (United States)

    Chicharro, J; Lopez-Calderon, A; Hoyos, J; Martin-Velasco, A; Villa, G; Villanua, M; Lucia, A

    2001-01-01

    Objectives—To determine whether consecutive bouts of intense endurance exercise over a three week period alters serum concentrations of insulin-like growth factor I (IGF-I) and/or its binding proteins. Methods—Seventeen professional cyclists (mean (SEM) VO2MAX, 74.7 (2.1) ml/kg/min; age, 27 (1) years) competing in a three week tour race were selected as subjects. Blood samples were collected at each of the following time points: t0 (control, before the start of competition), t1 (end of first week), and t3 (end of third week). Serum levels of both total and free IGF-I and IGF binding proteins 1 and 3 (IGFBP-1 and IGFBP-3) were measured in each of the samples. Cortisol levels were measured in nine subjects. Results—A significant (p<0.01) increase was found in total IGF-I and IGFBP-1 at both t1 and t3 compared with to (IGF-I: 110.9 (17.7), 186.8 (12.0), 196.9 (14.7) ng/ml at t0, t1, and t3 respectively; IGFBP-1: 54.6 (6.6), 80.6 (8.0), and 89.2 (7.9) ng/ml at t0, t1, and t3 respectively). A significant (p<0.01) decrease was noted in free IGF-I at t3 compared with both to and t1 (t0: 0.9 (0.1) ng/ml; t1: 0.9 (0.1) ng/ml; t3: 0.7 (0.1) ng/ml); in contrast, IGFBP-3 levels remained stable throughout the race. Conclusions—It would appear that the increase in circulating levels of both IGF-I and its binding protein IGFBP-1 is a short term (one week) endocrine adaptation to endurance exercise. After three weeks of training, total IGF-I and IGFBP-1 remained stable, whereas free IGF-I fell below starting levels. Key Words: cycling; insulin-like growth factor; exercise; endurance; binding proteins PMID:11579061

  13. mTORC2 promotes type I insulin-like growth factor receptor and insulin receptor activation through the tyrosine kinase activity of mTOR.

    Science.gov (United States)

    Yin, Yancun; Hua, Hui; Li, Minjing; Liu, Shu; Kong, Qingbin; Shao, Ting; Wang, Jiao; Luo, Yuanming; Wang, Qian; Luo, Ting; Jiang, Yangfu

    2016-01-01

    Mammalian target of rapamycin (mTOR) is a core component of raptor-mTOR (mTORC1) and rictor-mTOR (mTORC2) complexes that control diverse cellular processes. Both mTORC1 and mTORC2 regulate several elements downstream of type I insulin-like growth factor receptor (IGF-IR) and insulin receptor (InsR). However, it is unknown whether and how mTOR regulates IGF-IR and InsR themselves. Here we show that mTOR possesses unexpected tyrosine kinase activity and activates IGF-IR/InsR. Rapamycin induces the tyrosine phosphorylation and activation of IGF-IR/InsR, which is largely dependent on rictor and mTOR. Moreover, mTORC2 promotes ligand-induced activation of IGF-IR/InsR. IGF- and insulin-induced IGF-IR/InsR phosphorylation is significantly compromised in rictor-null cells. Insulin receptor substrate (IRS) directly interacts with SIN1 thereby recruiting mTORC2 to IGF-IR/InsR and promoting rapamycin- or ligand-induced phosphorylation of IGF-IR/InsR. mTOR exhibits tyrosine kinase activity towards the general tyrosine kinase substrate poly(Glu-Tyr) and IGF-IR/InsR. Both recombinant mTOR and immunoprecipitated mTORC2 phosphorylate IGF-IR and InsR on Tyr1131/1136 and Tyr1146/1151, respectively. These effects are independent of the intrinsic kinase activity of IGF-IR/InsR, as determined by assays on kinase-dead IGF-IR/InsR mutants. While both rictor and mTOR immunoprecitates from rictor(+/+) MCF-10A cells exhibit tyrosine kinase activity towards IGF-IR and InsR, mTOR immunoprecipitates from rictor(-/-) MCF-10A cells do not induce IGF-IR and InsR phosphorylation. Phosphorylation-deficient mutation of residue Tyr1131 in IGF-IR or Tyr1146 in InsR abrogates the activation of IGF-IR/InsR by mTOR. Finally, overexpression of rictor promotes IGF-induced cell proliferation. Our work identifies mTOR as a dual-specificity kinase and clarifies how mTORC2 promotes IGF-IR/InsR activation.

  14. IGF-II Promotes Stemness of Neural Restricted Precursors

    Science.gov (United States)

    Ziegler, Amber N.; Schneider, Joel S.; Qin, Mei; Tyler, William A.; Pintar, John E.; Fraidenraich, Diego; Wood, Teresa L.; Levison, Steven W.

    2016-01-01

    Insulin-like growth factor (IGF)-I and IGF-II regulate brain development and growth through the IGF type 1 receptor (IGF-1R). Less appreciated is that IGF-II, but not IGF-I, activates a splice variant of the insulin receptor (IR) known as IR-A. We hypothesized that IGF-II exerts distinct effects from IGF-I on neural stem/progenitor cells (NSPs) via its interaction with IR-A. Immunofluorescence revealed high IGF-II in the medial region of the subventricular zone (SVZ) comprising the neural stem cell niche, with IGF-II mRNA predominant in the adjacent choroid plexus. The IGF-1R and the IR isoforms were differentially expressed with IR-A predominant in the medial SVZ, whereas the IGF-1R was more abundant laterally. Similarly, IR-A was more highly expressed by NSPs, whereas the IGF-1R was more highly expressed by lineage restricted cells. In vitro, IGF-II was more potent in promoting NSP expansion than either IGF-I or standard growth medium. Limiting dilution and differentiation assays revealed that IGF-II was superior to IGF-I in promoting stemness. In vivo, NSPs propagated in IGF-II migrated to and took up residence in periventricular niches while IGF-I-treated NSPs predominantly colonized white matter. Knockdown of IR or IGF-1R using shRNAs supported the conclusion that the IGF-1R promotes progenitor proliferation, whereas the IR is important for self-renewal. Q-PCR revealed that IGF-II increased Oct4, Sox1, and FABP7 mRNA levels in NSPs. Our data support the conclusion that IGF-II promotes the self-renewal of neural stem/progenitors via the IR. By contrast, IGF-1R functions as a mitogenic receptor to increase precursor abundance. PMID:22593020

  15. IGF-1 attenuates LPS induced pro-inflammatory cytokines expression in buffalo (Bubalus bubalis) granulosa cells.

    Science.gov (United States)

    Onnureddy, K; Ravinder; Onteru, Suneel Kumar; Singh, Dheer

    2015-03-01

    Interaction between immune and endocrine system is a diverse process influencing cellular function and homeostasis in animals. Negative energy balance (NEB) during postpartum period in dairy animals usually suppresses these systems resulting in reproductive tract infection and infertility. These negative effects could be due to competition among endocrine and immune signaling pathways for common signaling molecules. The present work studied the effect of IGF-1 (50 ng/ml) on LPS (1 μg/ml) mediated pro-inflammatory cytokine expression (IL-1β, TNF-α, IL-6) and aromatase (CYP19A1) genes' expressions as well as proliferation of buffalo granulosa cells. The crosstalk between LPS and IGF-1 was also demonstrated through studying the activities of downstream signaling molecules (ERK1/2, Akt, NF-κB) by western blot and immunostaining. Gene expression analysis showed that IGF-1 significantly reduced the LPS induced expression of IL-1β, TNF-α and IL-6. LPS alone inhibited the CYP19A1 expression. However, co-treatment with IGF-1 reversed the inhibitory effect of LPS on CYP19A1 expression. LPS alone did not affect granulosa cell proliferation, but co-treatment with IGF-1, and IGF-1 alone enhanced the proliferation. Western blot results demonstrated that LPS caused the nuclear translocation of the NF-κB and increased the phosphorylation of ERK1/2 and Akt maximum at 15 min and 60 min, respectively. Nonetheless, co-treatment with IGF-1 delayed LPS induced phosphorylation of ERK1/2 (peak at 120 min), while promoting early Akt phosphorylation (peak at 5 min) with no effect on NF-κB translocation. Overall, IGF-1 delayed and reversed the effects of LPS, suggesting that high IGF-1 levels may combat infection during critical periods like NEB in postpartum dairy animals. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Effect of i.p. insulin administration onIGF1 and IGFBP1 in type1 diabetes

    NARCIS (Netherlands)

    van Dijk, P R; Logtenberg, S J J; Groenier, K H; Kleefstra, N; Bilo, H J G; Arnqvist, H J

    2014-01-01

    In type 1 diabetes mellitus (T1DM), low concentrations of IGF1 and high concentrations of IGF-binding protein 1 (IGFBP1) have been reported. It has been suggested that these abnormalities in the GH-IGF1 axis are due to low insulin concentrations in the portal vein. We hypothesized that the i.p.

  17. Study on the relationship between serum TNF-α, IGF-I levels and lipid peroxidation in patients with fatty liver

    International Nuclear Information System (INIS)

    Li Yuqiang; Niu Guoping

    2006-01-01

    Objective: To assess the relationship between serum TNF-α, IGF-I levels and lipid peroxidation in patients with fatty liver. Methods: Serum TNF-α, IGF-I (with RIA) levels were examined in 44 patients with fatty liver and 30 controls. Ser- um levels of malondialdehyde (MDA), superoxidase (SOD) were measured with chemocolorimetry in these subjects. Results: Serum levels of TNF-α, IGF-I were significantly higher in patients with fatty liver than those in controls P<0.01 ), while the serum levels of MDA, SOD were significantly lower (P<0.01). Serum levels of IGF-I were negatively correlated with MDA levels ( r -0. 4132, P<0.05), TNF-α levels were positive correlated with MDA levels (r=0.4318, P<0.05). Conclusion: Lipid peroxidation was present in patients with fatty liver, with correlated changes of TNF-α and IGF-I levels. (authors)

  18. Acute regulation of IGF-I by alterations in post-exercise macronutrients

    Science.gov (United States)

    This investigation sought to examine the contributions of exercise and nutrient replenishment on in vivo regulation of the insulin-like growth factor-I (IGF-I) axis components. Eight college-aged males completed three high-intensity interval training (HIIT) protocols followed by three post-exercise ...

  19. Clinical significance of determination of serum IGF-I, TNF-α and SS levels in patients with chronic viral hepatitis

    International Nuclear Information System (INIS)

    Zhu Peiming

    2009-01-01

    Objective: To study the clinical significance of changes of serum IGF-I, TNF-α and somatostatin(SS) levels in patients with chronic viral hepatitis. Methods: Serum IGF-I, TNF-α and SS levels were determined with RIA in 30 patients with chronic viral hepatitis (B hepatitis, n=24,C hepatitis, n=6) and 30 controls.Results The serum IGF-I, TNF-α and SS levels in the patients were all significantly higher than those in controls (P<0.01). Conclusion: Serum IGF-I, TNF-α and SS levels were markedly increased in patients with chronic viral hepatitis, the exact mechanism and consequence of the changes required further study. (authors)

  20. Polymorphism in NPY and IGF-I genes associate with reproductive ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-10-05

    Oct 5, 2009 ... effects of NPY and IGF-I genes on reproductive traits of chickens. Key words: ... flavor and good egg quality are accorded with Chinese consumers' taste. ... Numerous studies in mammals and more recently in teleost fish.

  1. Antibody-based therapeutics against components of the IGF system

    OpenAIRE

    Feng, Yang; Dimitrov, Dimiter S.

    2012-01-01

    The insulin-like growth factor I (IGF-I) receptor (IGF-1R) is overexpressed in most human neoplasms tested so far. Many tumors in young patients produce high levels of the IGF-1R ligands, IGF-I and IGF-II. Given the complexity of the IGF signaling pathway, its complete inhibition may require combination therapies with antibodies targeting both IGF-1R and IGF-II.

  2. Role of heterotrimeric G protein and calcium in cardiomyocyte hypertrophy induced by IGF-1.

    Science.gov (United States)

    Carrasco, Loreto; Cea, Paola; Rocco, Paola; Peña-Oyarzún, Daniel; Rivera-Mejias, Pablo; Sotomayor-Flores, Cristian; Quiroga, Clara; Criollo, Alfredo; Ibarra, Cristian; Chiong, Mario; Lavandero, Sergio

    2014-04-01

    In the heart, insulin-like growth factor-1 (IGF-1) is a peptide with pro-hypertrophic and anti-apoptotic actions. The pro-hypertrophic properties of IGF-1 have been attributed to the extracellular regulated kinase (ERK) pathway. Recently, we reported that IGF-1 also increases intracellular Ca(2+) levels through a pertussis toxin (PTX)-sensitive G protein. Here we investigate whether this Ca(2+) signal is involved in IGF-1-induced cardiomyocyte hypertrophy. Our results show that the IGF-1-induced increase in Ca(2+) level is abolished by the IGF-1 receptor tyrosine kinase inhibitor AG538, PTX and the peptide inhibitor of Gβγ signaling, βARKct. Increases in the activities of Ca(2+) -dependent enzymes calcineurin, calmodulin kinase II (CaMKII), and protein kinase Cα (PKCα) were observed at 5 min after IGF-1 exposure. AG538, PTX, βARKct, and the dominant negative PKCα prevented the IGF-1-dependent phosphorylation of ERK1/2. Participation of calcineurin and CaMKII in ERK phosphorylation was discounted. IGF-1-induced cardiomyocyte hypertrophy, determined by cell size and β-myosin heavy chain (β-MHC), was prevented by AG538, PTX, βARKct, dominant negative PKCα, and the MEK1/2 inhibitor PD98059. Inhibition of calcineurin with CAIN did not abolish IGF-1-induced cardiac hypertrophy. We conclude that IGF-1 induces hypertrophy in cultured cardiomyocytes by activation of the receptor tyrosine kinase activity/βγ-subunits of a PTX-sensitive G protein/Ca(2+) /PKCα/ERK pathway without the participation of calcineurin. © 2013 Wiley Periodicals, Inc.

  3. Nuclear insulin-like growth factor 1 receptor phosphorylates proliferating cell nuclear antigen and rescues stalled replication forks after DNA damage.

    Science.gov (United States)

    Waraky, Ahmed; Lin, Yingbo; Warsito, Dudi; Haglund, Felix; Aleem, Eiman; Larsson, Olle

    2017-11-03

    We have previously shown that the insulin-like growth factor 1 receptor (IGF-1R) translocates to the cell nucleus, where it binds to enhancer-like regions and increases gene transcription. Further studies have demonstrated that nuclear IGF-1R (nIGF-1R) physically and functionally interacts with some nuclear proteins, i.e. the lymphoid enhancer-binding factor 1 (Lef1), histone H3, and Brahma-related gene-1 proteins. In this study, we identified the proliferating cell nuclear antigen (PCNA) as a nIGF-1R-binding partner. PCNA is a pivotal component of the replication fork machinery and a main regulator of the DNA damage tolerance (DDT) pathway. We found that IGF-1R interacts with and phosphorylates PCNA in human embryonic stem cells and other cell lines. In vitro MS analysis of PCNA co-incubated with the IGF-1R kinase indicated tyrosine residues 60, 133, and 250 in PCNA as IGF-1R targets, and PCNA phosphorylation was followed by mono- and polyubiquitination. Co-immunoprecipitation experiments suggested that these ubiquitination events may be mediated by DDT-dependent E2/E3 ligases ( e.g. RAD18 and SHPRH/HLTF). Absence of IGF-1R or mutation of Tyr-60, Tyr-133, or Tyr-250 in PCNA abrogated its ubiquitination. Unlike in cells expressing IGF-1R, externally induced DNA damage in IGF-1R-negative cells caused G 1 cell cycle arrest and S phase fork stalling. Taken together, our results suggest a role of IGF-1R in DDT. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  4. FOXO1 Content Is Reduced in Cystic Fibrosis and Increases with IGF-I Treatment

    Directory of Open Access Journals (Sweden)

    Arianna Smerieri

    2014-10-01

    Full Text Available Cystic fibrosis-related diabetes is to date the most frequent complication in cystic fibrosis (CF. The mechanisms underlying this condition are not well understood, and a possible role of insulin resistance is debated. We investigated insulin signal transduction in CF. Total insulin receptor, IRS1, p85 PI3K, and AKT contents were substantially normal in CF cells (CFBE41o-, whereas winged helix forkhead (FOXO1 contents were reduced both in baseline conditions and after insulin stimulation. In addition, CF cells showed increased ERK1/2, and reduced β2 arrestin contents. No significant change in SOCS2 was observed. By using a CFTR inhibitor and siRNA, changes in FOXO1 were related to CFTR loss of function. In a CF-affected mouse model, FOXO1 content was reduced in the muscle while no significant difference was observed in liver and adipose tissue compared with wild-type. Insulin-like growth factor 1 (IGF-I increased FOXO1 content in vitro and in vivo in muscle and adipose tissue. In conclusion; we present the first description of reduced FOXO1 content in CF, which is compatible with reduced gluconeogenesis and increased adipogenesis, both features of insulin insensitivity. IGF-I treatment was effective in increasing FOXO1, thereby suggesting that it could be considered as a potential treatment in CF patients possibly to prevent and treat cystic fibrosis-related diabetes.

  5. Skeletal muscle PLIN3 and PLIN5 are serine phosphorylated at rest and following lipolysis during adrenergic or contractile stimulation

    Science.gov (United States)

    MacPherson, Rebecca E K; Vandenboom, Rene; Roy, Brian D; Peters, Sandra J

    2013-01-01

    In adipose tissue, access of adipose triglyceride and hormone-sensitive lipases (ATGL and HSL) to the lipid droplet depends on PLIN1 phosphorylation, however, PLIN1 is not expressed in skeletal muscle and the phosphorylation of the expressed PLINs has yet to be investigated. Further, direct interactions between skeletal muscle PLINs and HSL are unknown. We investigated the isolated and combined effects of epinephrine and contraction on PLIN-to-lipase interactions as well as phosphorylation. Isolated rat solei were assigned to one of four 30 min in vitro conditions (25°C): (1) rest; (2) intermittent tetanic stimulation (60 Hz for 150 msec; train rate 20/min); (3) 5 nmol/L epinephrine; (4) intermittent tetanic stimulation and 5 nmol/L epinephrine. Immunoprecipitation of serine phosphorylated proteins followed by Western blotting for PLIN2, PLIN3, PLIN5, revealed that only PLIN2 is not phosphorylated under any of the experimental conditions. This is the first study to show that in whole rat skeletal muscle PLIN3 and PLIN5 are serine phosphorylated. The degree of serine phosphorylation remained unchanged following adrenergic and/or contractile stimulation. Oil red O staining of muscle sections for lipid content shows a significant decrease following each condition, confirming lipolysis occurred (P < 0.05). PLIN2, 3, and 5 all interact with HSL and ATGL, but these interactions were unchanged following treatments. Our results show that in skeletal muscle, PLIN2 is not serine phosphorylated at rest or with lipolytic stimulation and that while PLIN3, PLIN5 are serine phosphorylated at rest, the degree of phosphorylation does not change with lipolytic stimulation. PMID:24303154

  6. The DNA methylation status of MyoD and IGF-I genes are correlated with muscle growth during different developmental stages of Japanese flounder (Paralichthys olivaceus).

    Science.gov (United States)

    Huang, Yajuan; Wen, Haishen; Zhang, Meizhao; Hu, Nan; Si, Yufeng; Li, Siping; He, Feng

    2018-05-01

    Many genes related to muscle growth modulate myoblast proliferation and differentiation and promote muscle hypertrophy. MyoD is a myogenic determinant that contributes to myoblast determination, and insulin-like growth factor 1 (IGF-I) interacts with MyoD to regulate muscle hypertrophy and muscle mass. In this study, we aimed to assess DNA methylation and mRNA expression patterns of MyoD and IGF-I during different developmental stages of Japanese flounder, and to examine the relationship between MyoD and IGF-I gene. DNA and RNA were extracted from muscles, and DNA methylation of MyoD and IGF-I promoter and exons was detected by bisulfite sequencing. The relative expression of MyoD and IGF-I was measured by quantitative polymerase chain reaction. IGF-I was measured by radioimmunoassay. Interestingly, the lowest expression of MyoD and IGF-I emerged at larva stage, and the mRNA expression was negatively associated with methylation. We hypothesized that many skeletal muscle were required to complete metamorphosis; thus, the expression levels of MyoD and IGF-I genes increased from larva stage and then decreased. The relative expression levels of MyoD and IGF-I exhibited similar patterns, suggesting that MyoD and IGF-I regulated muscle growth through combined effects. Changes in the concentrations of IGF-I hormone were similar to those of IGF-I gene expression. Our results the mechanism through which MyoD and IGF-I regulate muscle development and demonstrated that MyoD interacted with IGF-I to regulate muscle growth during different developmental stages. Copyright © 2018 Elsevier Inc. All rights reserved.

  7. High protein diets do not attenuate decrements in testosterone and IGF-I during energy deficit.

    Science.gov (United States)

    Henning, Paul C; Margolis, Lee M; McClung, James P; Young, Andrew J; Pasiakos, Stefan M

    2014-05-01

    Energy deficit (ED) diminishes fat-free mass (FFM) with concomitant reductions in anabolic hormone secretion. A modest increase in protein to recommended dietary allowance (RDA) levels during ED minimally attenuates decrements in insulin-like growth factor-I (IGF-I). The impact of dietary protein above the RDA on circulating anabolic hormones and their relationships with FFM in response to ED are not well described. Thirty-three adults were assigned diets providing protein at 0.8 (RDA), 1.6 (2×-RDA), and 2.4 (3×-RDA) g/kg/d for 31days. Testosterone, sex-hormone binding globulin (SHBG) and IGF-I system components were assessed after a 10-day period of weight-maintenance (WM) and after a 21-day period of ED (40%) achieved by an increase in energy expenditure and decreased energy intake. Associations between the change in FFM and anabolic hormone levels were determined. As compared to WM and regardless of dietary protein intake, total and free testosterone, total IGF-I, and acid-labile subunit decreased (Phormones or IGF-I system components measured. Changes in FFM in response to ED were negatively associated with acid-labile subunit (ALS) (r=-0.62, Phormone concentrations. Published by Elsevier Inc.

  8. Genomewide meta-analysis identifies loci associated with IGF-I and IGFBP-3 levels with impact on age-related traits

    NARCIS (Netherlands)

    A. Teumer (Alexander); Q. Qi; M. Nethander (Maria); H. Aschard (Hugues); S. Bandinelli (Stefania); M. Beekman (Marian); S.I. Berndt (Sonja); M. Bidlingmaier (Martin); L. Broer (Linda); A.R. Cappola (Anne); Ceda, G.P. (Gian Paolo); S.J. Chanock (Stephen); M.-H. Chen (Ming-Huei); Chen, T.C. (Tai C.); Y.D. Chen (Y.); Chung, J. (Jonathan); Del Greco Miglianico, F. (Fabiola); J. Eriksson (Joel); L. Ferrucci (Luigi); N. Friedrich (Nele); C. Gnewuch (Carsten); M. Goodarzi (Mark); N. Grarup (Niels); Guo, T. (Tingwei); Hammer, E. (Elke); R.B. Hayes (Richard); A.A. Hicks (Andrew); A. Hofman (Albert); J.J. Houwing-Duistermaat (Jeanine); Hu, F. (Frank); D. Hunter (David); L.L.N. Husemoen (Lise Lotte); A.J. Isaacs (Aaron); K.B. Jacobs (Kevin); J.A.M.J.L. Janssen (Joseph); J.-O. Jansson (John-Olov); Jehmlich, N. (Nico); Johnson, S. (Simon); A. Juul (Anders); M. Karlsson (Magnus); T.O. Kilpeläinen (Tuomas); P. Kovacs (Peter); P. Kraft (Peter); Li, C. (Chao); A. Linneberg (Allan); Y. Liu (YongMei); R.J.F. Loos (Ruth); M. Lorentzon (Mattias); Y. Lu (Yingchang); M. Maggio (Marcello); R. Mägi (Reedik); J.B. Meigs (James); D. Mellström (Dan); M. Nauck (Matthias); A.B. Newman (Anne B.); M.N. Pollak (Michael); P.P. Pramstaller (Peter Paul); I. Prokopenko (Inga); B.M. Psaty (Bruce); M. Reincke (Martin); E.B. Rimm (Eric B.); Rotter, J.I. (Jerome I.); Saint Pierre, A. (Aude); C. Schurmann (Claudia); S. Seshadri (Sudha); Sjögren, K. (Klara); P.E. Slagboom (Eline); Strickler, H.D. (Howard D.); M. Stumvoll (Michael); Y. Suh (Yousin); Q. Sun (Qi); Zhang, C. (Cuilin); Svensson, J. (Johan); T. Tanaka (Toshiko); Tare, A. (Archana); A. Tönjes (Anke); H.-W. Uh (Hae-Won); C.M. van Duijn (Cornelia); D. van Heemst (Diana); L. Vandenput (Liesbeth); R.S. Vasan (Ramachandran Srini); U. Völker (Uwe); S.M. Willems (Sara); C. Ohlsson (Claes); H. Wallaschofski (Henri); R.C. Kaplan (Robert)

    2016-01-01

    textabstractThe growth hormone/insulin-like growth factor (IGF) axis can be manipulated in animal models to promote longevity, and IGF-related proteins including IGF-I and IGF-binding protein-3 (IGFBP-3) have also been implicated in risk of human diseases including cardiovascular diseases, diabetes,

  9. Insulin-like growth factor-I (IGF-1), IGF-binding protein-3 (IGFBP-3) and mammographic features.

    Science.gov (United States)

    Izzo, L; Meggiorini, M L; Nofroni, I; Pala, A; De Felice, C; Meloni, P; Simari, T; Izzo, S; Pugliese, F; Impara, L; Merlini, G; Di Cello, P; Cipolla, V; Forcione, A R; Paliotta, A; Domenici, L; Bolognese, A

    2012-05-01

    The IGF system has recently been shown to play an important role in the regulation of breast tumor cell proliferation. However, also breast density is currently considered as the strongest breast cancer risk factor. It is not yet clear whether these factors are interrelated and if and how they are influenced by menopausal status. The purpose of this study was to examine the possible effects of IGF-1 and IGFBP-3 and IGF-1/IGFBP-3 molar ratio on mammographic density stratified by menopausal status. A group of 341 Italian women were interviewed to collect the following data: family history of breast cancer, reproductive and menstrual factors, breast biopsies, previous administration of hormonal contraceptive therapy, hormone replacement therapy (HRT) in menopause and lifestyle information. A blood sample was drawn for determination of IGF-1, IGFBP-3 levels. IGF-1/ IGFBP-3 molar ratio was then calculated. On the basis of recent mammograms the women were divided into two groups: dense breast (DB) and non-dense breast (NDB). Student's t-test was employed to assess the association between breast density and plasma level of IGF-1, IGFBP-3 and molar ratio. To assess if this relationship was similar in subgroups of pre- and postmenopausal women, the study population was stratified by menopausal status and Student's t-test was performed. Finally, multivariate analysis was employed to evaluate if there were confounding factors that might influence the relationship between growth factors and breast density. The analysis of the relationship between mammographic density and plasma level of IGF-1, IGFBP-3 and IGF-1/ IGFBP-3 molar ratio showed that IGF-1 levels and molar ratio varied in the two groups resulting in higher mean values in the DB group (IGF-1: 109.6 versus 96.6 ng/ml; p= 0.001 and molar ratio 29.4 versus 25.5 ng/ml; p= 0.001) whereas IGFBP-3 showed similar values in both groups (DB and NDB). Analysis of plasma level of IGF-1, IGFBP-3 and IGF-1/IGFBP-3 molar ratio

  10. Proline-rich tyrosine kinase 2 (Pyk2 regulates IGF-I-induced cell motility and invasion of urothelial carcinoma cells.

    Directory of Open Access Journals (Sweden)

    Marco Genua

    Full Text Available The insulin-like growth factor receptor I (IGF-IR plays an essential role in transformation by promoting cell growth and protecting cancer cells from apoptosis. We have recently demonstrated that the IGF-IR is overexpressed in invasive bladder cancer tissues and promotes motility and invasion of urothelial carcinoma cells. These effects require IGF-I-induced Akt- and MAPK-dependent activation of paxillin. The latter co-localizes with focal adhesion kinases (FAK at dynamic focal adhesions and is critical for promoting motility of urothelial cancer cells. FAK and its homolog Proline-rich tyrosine kinase 2 (Pyk2 modulate paxillin activation; however, their role in regulating IGF-IR-dependent signaling and motility in bladder cancer has not been established. In this study we demonstrate that FAK was not required for IGF-IR-dependent signaling and motility of invasive urothelial carcinoma cells. On the contrary, Pyk2, which was strongly activated by IGF-I, was critical for IGF-IR-dependent motility and invasion and regulated IGF-I-dependent activation of the Akt and MAPK pathways. Using immunofluorescence and AQUA analysis we further discovered that Pyk2 was overexpressed in bladder cancer tissues as compared to normal tissue controls. Significantly, in urothelial carcinoma tissues there was increased Pyk2 localization in the nuclei as compared to normal tissue controls. These results provide the first evidence of a specific Pyk2 activity in regulating IGF-IR-dependent motility and invasion of bladder cancer cells suggesting that Pyk2 and the IGF-IR may play a critical role in the invasive phenotype in urothelial neoplasia. In addition, Pyk2 and the IGF-IR may serve as novel biomarkers with diagnostic and prognostic significance in bladder cancer.

  11. Hand size and growth in untreated and IGF-I treated patients with Laron syndrome.

    Science.gov (United States)

    Konen, O; Silbergeld, A; Lilos, P; Kornreich, L; Laron, Z

    2009-03-01

    We have previously reported on the linear growth, growth of the head circumference and foot length in untreated and IGF-I treated patients with Laron syndrome (LS) (primary GH insensitivity). To assess the size and growth of the hands in patients with LS from early childhood to adult age. Ten IGF-I treated children with LS (4 M, 6 F) and 24 untreated patients (10 M, 14 F) were studied. Measurements of palm length were made on available standardized hand X-rays from infancy to adult age. The measurements were compared to normal references and SD values were calculated for each measurement. The growth of the hand was compared to the concomitant height of the body. Hand SDS in untreated patients with LS decreased with age, from a mean of -2.8 +/- 0.7 (age 1-3 years) to -7.3 +/- 0.8 (age 13-15 years) and to -9.0 +/- 3.9 (age 40-50 years). During 9 years of IGF-I treatment the hand size deficit SDS did not improve in contradistinction to the height SDS which decreased from -6.2 +/- 1.2 to -3.9 +/- 0.5. Congenital IGF-I deficiency, as in Laron syndrome, profoundly affects the size and growth of the hand as part of its growth retardation characteristics, resulting in acromicria.

  12. Systemic administration of insulin-like growth factor I (IGF-I) causes growth of the rat prostate

    DEFF Research Database (Denmark)

    Tørring, N; Vinter-Jensen, L; Pedersen, S B

    1997-01-01

    PURPOSE: To investigate the effects of insulin-like growth factor I (IGF-I) and epidermal growth factor (EGF) on the rat prostate. In addition, we investigated the effect of ornithine decarboxylase (ODC) inhibition with alpha-diflouromethylornitine (DFMO) on the expected growth of the prostate.MA...

  13. Regulation of the pituitary tumor transforming gene by insulin-like-growth factor-I and insulin differs between malignant and non-neoplastic astrocytes

    International Nuclear Information System (INIS)

    Chamaon, Kathrin; Kirches, Elmar; Kanakis, Dimitrios; Braeuninger, Stefan; Dietzmann, Knut; Mawrin, Christian

    2005-01-01

    The reasons for overexpression of the oncogene pituitary tumor transforming gene (PTTG) in tumors are still not fully understood. A possible influence of the insulin-like growth factor I (Igf-I) may be of interest, since enhanced Igf-I signalling was reported in various human tumors. We examined the influence of Igf-I and insulin on PTTG expression in human astrocytoma cells in comparison to proliferating non-neoplastic rat embryonal astrocytes. PTTG mRNA expression and protein levels were increased in malignant astrocytes treated with Igf-I or insulin, whereas in rat embryonic astrocytes PTTG expression and protein levels increased only when cells were exposed to Igf-I. Enhanced transcription did not occur after treatment with inhibitors of phosphoinositol-3-kinase (PI3K) and mitogen-activated protein kinase (MAPK), blocking the two basic signalling pathways of Igf-I and insulin. In addition to this transcriptional regulation, both kinases directly bind to PTTG, suggesting a second regulatory route by phosphorylation. However, the interaction of endogenous PTTG with MAPK and PI3K, as well as PTTG phosphorylation were independent from Igf-I or insulin. The latter results were also found in human testis, which contains high PTTG levels as well as in nonneoplastic astrocytes. This suggest, that PI3K and MAPK signalling is involved in PTTG regulation not only in malignant astrocytomas but also in non-tumorous cells

  14. IGF-I: A key growth factor that regulates neurogenesis and synaptogenesis from embryonic to adult stages of the brain

    Directory of Open Access Journals (Sweden)

    Vanesa eNieto-Estévez

    2016-02-01

    Full Text Available The generation of neurons in the adult mammalian brain requires the activation of quiescent neural stem cells (NSCs. This activation and the sequential steps of neuron formation from NSCs are regulated by a number of stimuli, which include growth factors. Insulin-like growth factor-I (IGF-I exert pleiotropic effects, regulating multiple cellular processes depending on their concentration, cell type and the developmental stage of the animal. Although IGF-I expression is relatively high in the embryonic brain its levels drop sharply in the adult brain except in neurogenic regions, i.e., the hippocampus (HP and the subventricular zone-olfactory bulb (SVZ-OB. By contrast, the expression of IGF-IR remains relatively high in the brain irrespective of the age of the animal. Evidence indicates that IGF-I influences NSC proliferation and differentiation into neurons and glia as well as neuronal maturation including synapse formation. Furthermore, recent studies have shown that IGF-I not only promote adult neurogenesis by regulating NSC number and differentiation but also, by influencing neuronal positioning and migration as described during SVZ-OB neurogenesis. In this article we will revise and discuss the actions reported for IGF-I signaling in a variety of in vitro and in vivo models, focusing on the maintenance and proliferation of NSCs/progenitors, neurogenesis and neuron integration in synaptic circuits.

  15. IGF-I: A Key Growth Factor that Regulates Neurogenesis and Synaptogenesis from Embryonic to Adult Stages of the Brain

    Science.gov (United States)

    Nieto-Estévez, Vanesa; Defterali, Çağla; Vicario-Abejón, Carlos

    2016-01-01

    The generation of neurons in the adult mammalian brain requires the activation of quiescent neural stem cells (NSCs). This activation and the sequential steps of neuron formation from NSCs are regulated by a number of stimuli, which include growth factors. Insulin-like growth factor-I (IGF-I) exert pleiotropic effects, regulating multiple cellular processes depending on their concentration, cell type, and the developmental stage of the animal. Although IGF-I expression is relatively high in the embryonic brain its levels drop sharply in the adult brain except in neurogenic regions, i.e., the hippocampus (HP) and the subventricular zone-olfactory bulb (SVZ-OB). By contrast, the expression of IGF-IR remains relatively high in the brain irrespective of the age of the animal. Evidence indicates that IGF-I influences NSC proliferation and differentiation into neurons and glia as well as neuronal maturation including synapse formation. Furthermore, recent studies have shown that IGF-I not only promote adult neurogenesis by regulating NSC number and differentiation but also by influencing neuronal positioning and migration as described during SVZ-OB neurogenesis. In this article we will revise and discuss the actions reported for IGF-I signaling in a variety of in vitro and in vivo models, focusing on the maintenance and proliferation of NSCs/progenitors, neurogenesis, and neuron integration in synaptic circuits. PMID:26941597

  16. Chronic alcohol consumption, type 2 diabetes mellitus, insulin-like growth factor-I (IGF-I), and growth hormone (GH) in ethanol-treated diabetic rats.

    Science.gov (United States)

    Kim, Soo-Jeong; Ju, Anes; Lim, Seul-Gi; Kim, Dai-Jin

    2013-11-13

    Alcohol has deleterious influences on glucose metabolism which may contribute to the development of type 2 diabetes mellitus (T2DM). Insulin-like growth factor I (IGF-I) and growth hormone (GH), which interact with insulin to modulate metabolic control, have been shown to be related to impaired glucose tolerance. This study was conducted to assess the possibility that altered circulating IGF-I and GH levels contribute to the exacerbation of T2DM by alcohol use in type 2 diabetic Otsuka Long-Evans Tokushima Fatty (OLETF) rats and non-diabetic Long-Evans Tokushima Otsuka (LETO) rats. OLETF rats were pair-fed a Lieber-DeCarli Regular Ethanol diet and LETO rats were pair-fed a control diet for 6 weeks. At 6 weeks, an Intraperitoneal Glucose Tolerance Test (IP-GTT) was performed and IGF-I and GH levels were evaluated. Prior to an IP-GTT, OLETF-Ethanol (O-E) group had significantly a decrease in the mean glucose levels compared to OLETF-Control (O-C) group. At 120 min post IP-GTT, the O-E group had significantly an increase in the mean glucose levels compared to O-C group. The serum IGF-I levels were significantly lower and the serum GH levels were significantly higher in the O-E group than in L-C group. These results suggest that IGF-I and GH are prominent in defining the risk and development of T2DM, and may be adversely affected by heavy alcohol use, possibly mediating its diabetogenic effects. Thus, the overall glucose intolerance in the setting of alcoholism may be attributable to inappropriate alteration of IGF-I and GH levels. © 2013. Published by Elsevier Inc. All rights reserved.

  17. The in vivo phosphorylation sites of rat brain dynamin I

    DEFF Research Database (Denmark)

    Graham, Mark E; Anggono, Victor; Bache, Nicolai

    2007-01-01

    -824). To resolve the discrepancy and to better understand the biological roles of dynI phosphorylation, we undertook a systematic identification of all phosphorylation sites in rat brain nerve terminal dynI. Using phosphoamino acid analysis, exclusively phospho-serine residues were found. Thr(780) phosphorylation...... of their relative abundance and relative responses to depolarization. The multiple phospho-sites suggest subtle regulation of synaptic vesicle endocytosis by new protein kinases and new protein-protein interactions. The homologous dynI and dynIII phosphorylation indicates a high mechanistic similarity. The results...

  18. A low-fat, whole-food vegan diet, as well as other strategies that down-regulate IGF-I activity, may slow the human aging process.

    Science.gov (United States)

    McCarty, Mark F

    2003-06-01

    A considerable amount of evidence is consistent with the proposition that systemic IGF-I activity acts as pacesetter in the aging process. A reduction in IGF-I activity is the common characteristic of rodents whose maximal lifespan has been increased by a wide range of genetic or dietary measures, including caloric restriction. The lifespans of breeds of dogs and strains of rats tend to be inversely proportional to their mature weight and IGF-I levels. The link between IGF-I and aging appears to be evolutionarily conserved; in worms and flies, lifespan is increased by reduction-of-function mutations in signaling intermediates homologous to those which mediate insulin/IGF-I activity in mammals. The fact that an increase in IGF-I activity plays a key role in the induction of sexual maturity, is consistent with a broader role for-IGF-I in aging regulation. If down-regulation of IGF-I activity could indeed slow aging in humans, a range of practical measures for achieving this may be at hand. These include a low-fat, whole-food, vegan diet, exercise training, soluble fiber, insulin sensitizers, appetite suppressants, and agents such as flax lignans, oral estrogen, or tamoxifen that decrease hepatic synthesis of IGF-I. Many of these measures would also be expected to decrease risk for common age-related diseases. Regimens combining several of these approaches might have a sufficient impact on IGF-I activity to achieve a useful retardation of the aging process. However, in light of the fact that IGF-I promotes endothelial production of nitric oxide and may be of especial importance to cerebrovascular health, additional measures for stroke prevention-most notably salt restriction-may be advisable when attempting to down-regulate IGF-I activity as a pro-longevity strategy.

  19. Sleep extension increases IGF-I concentrations before and during sleep deprivation in healthy young men.

    Science.gov (United States)

    Chennaoui, Mounir; Arnal, Pierrick J; Drogou, Catherine; Sauvet, Fabien; Gomez-Merino, Danielle

    2016-09-01

    Sleep deprivation is known to suppress circulating trophic factors such as insulin-like growth factor (IGF)-I and brain-derived neurotrophic factor (BDNF). This experiment examined the effect of an intervention involving 6 nights of extended sleep before total sleep deprivation on this catabolic profile. In a randomized crossover design, 14 young men (age range: 26-37 years) were either in an extended (EXT; time in bed: 2100-0700 h) or habitual (HAB: 2230-0700 h) sleep condition, followed by 3 days in the laboratory with blood sampling at baseline (B), after 24 h of sleep deprivation (24h-SD), and after 1 night of recovery sleep (R). In the EXT condition compared with the HAB condition, free IGF-I levels were significantly higher at B, 24h-SD, and R (P sleep deprivation was for insulin levels, which were significantly higher after R compared with B. In a healthy adult, additional sleep over 1 week increased blood concentrations of the anabolic factor IGF-I before and during 24 h of sleep deprivation and after the subsequent recovery night without effects on BDNF. With further research, these findings may prove to be important in guiding effective lifestyle modifications to limit physical or cognitive deficits associated with IGF-I decrease with age.

  20. Changes of blood and myocardial tissue contents of IGF-I after development of acute myocardial infarction in rat models

    International Nuclear Information System (INIS)

    Cao Heng; Wei Youquan

    2006-01-01

    Objective: To study the changes of IGF-I contents in blood and myocardium after experimental acute myocardial infarction in rat models. Methods: Rat models of acute myocardial infarction were prepared with intraperitoneal injection of isoproterenol. Eight models were sacrificed 48h later and another 8 models were sacrificed 14 days after preparation. Serum and myocardium homogenate contents of IGF-I were measured with RIA in these models as well as 8 control rats. Results: The serum and myocardial contents of IGF-I increased in the models sacrificed at 48h, but were not significantly higher than those in the controls (P>0.05). At 14 th day, the levels were significantly higher than those in controls and at 48h (both P<0.05). The serum and myocardial contents of IGF-I were mutually correlated in the controls and 14 day models (r=0.9987, r=0.9992; P<0.01). Conclusion After myocardial infarction, the serum and myocardial IGF-I contents increased along with the course of disease in the rat models. (authors)

  1. Changes of Cerebral and/or Peripheral Adenosine A1 Receptor and IGF-I Concentrations under Extended Sleep Duration in Rats

    Directory of Open Access Journals (Sweden)

    Mounir Chennaoui

    2017-11-01

    Full Text Available Extended sleep improves sustained attention and reduces sleep pressure in humans. Downregulation of adenosine A1 receptor (A1R and modulation of the neurotrophic factor insulin growth factor-1 (IGF-I in brain structures controlling attentional capacities could be involved. In the frontal cortex and hippocampus of rats, we measured adenosine A1R and IGF-I protein concentrations after photoperiod-induced sleep extension. Two groups of twelve rats were adapted over 14 days to a habitual (CON 12:12 light–dark (LD schedule and an extended (EXT 16:8 LD schedule. IGF-I content was also measured in plasma, liver, and skeletal muscle. In EXT, compared to CON rats, A1R content in the frontal cortex was significantly lower (p < 0.05, while IGF-I content was higher (p < 0.001, and no significant change was observed in the hippocampus. IGF-I content in plasma and muscle was higher (p < 0.001 and p < 0.01, while it was lower in liver (p < 0.001. The absolute weight and weight gain were higher in EXT rats (p < 0.01. These data suggest that 14 days under a 16:8 LD photoperiod respectively down- and upregulated cortical A1R and IGF-I levels. This photoperiod induced an anabolic profile with increased weight gain and circulating and muscular IGF-I levels. An extension of sleep duration might favor cerebral and peripheral anabolism, which may help attentional and physical capacities.

  2. MicroRNA-214 Reduces Insulin-like Growth Factor-1 (IGF-1) Receptor Expression and Downstream mTORC1 Signaling in Renal Carcinoma Cells*

    Science.gov (United States)

    Das, Falguni; Dey, Nirmalya; Bera, Amit; Kasinath, Balakuntalam S.; Ghosh-Choudhury, Nandini; Choudhury, Goutam Ghosh

    2016-01-01

    Elevated IGF-1/insulin-like growth factor-1 receptor (IGF-1R) autocrine/paracrine signaling in patients with renal cell carcinoma is associated with poor prognosis of the disease independent of their von Hippel-Lindau (VHL) status. Increased expression of IGF-1R in renal cancer cells correlates with their potency of tumor development and progression. The mechanism by which expression of IGF-1R is increased in renal carcinoma is not known. We report that VHL-deficient and VHL-positive renal cancer cells possess significantly decreased levels of mature, pre-, and pri-miR-214 than normal proximal tubular epithelial cells. We identified an miR-214 recognition element in the 3′UTR of IGF-1R mRNA and confirmed its responsiveness to miR-214. Overexpression of miR-214 decreased the IGF-1R protein levels, resulting in the inhibition of Akt kinase activity in both types of renal cancer cells. IGF-1 provoked phosphorylation and inactivation of PRAS40 in an Akt-dependent manner, leading to the activation of mTORC1 signal transduction to increase phosphorylation of S6 kinase and 4EBP-1. Phosphorylation-deficient mutants of PRAS40 and 4EBP-1 significantly inhibited IGF-1R-driven proliferation of renal cancer cells. Expression of miR-214 suppressed IGF-1R-induced phosphorylation of PRAS40, S6 kinase, and 4EBP-1, indicating inhibition of mTORC1 activity. Finally, miR-214 significantly blocked IGF-1R-forced renal cancer cell proliferation, which was reversed by expression of 3′UTR-less IGF-1R and constitutively active mTORC1. Together, our results identify a reciprocal regulation of IGF-1R levels and miR-214 expression in renal cancer cells independent of VHL status. Our data provide evidence for a novel mechanism for IGF-1R-driven renal cancer cell proliferation involving miR-214 and mTORC1. PMID:27226530

  3. Obesity alters gene expression for GH/IGF-I axis in mouse mammary fat pads: differential role of cortistatin and somatostatin.

    Directory of Open Access Journals (Sweden)

    Alicia Villa-Osaba

    Full Text Available Locally produced growth hormone (GH and IGF-I are key factors in the regulation of mammary gland (MG development and may be important in breast cancer development/progression. Somatostatin (SST and cortistatin (CORT regulate GH/IGF-I axis at various levels, but their role in regulating GH/IGF-I in MGs remains unknown. Since obesity alters the expression of these systems in different tissues and is associated to MG (patho physiology, we sought to investigate the role of SST/CORT in regulating GH/IGF-I system in the MGs of lean and obese mice. Therefore, we analyzed GH/IGF-I as well as SST/CORT and ghrelin systems expression in the mammary fat pads (MFPs of SST- or CORT-knockout (KO mice and their respective littermate-controls fed a low-fat (LF or a high-fat (HF diet for 16 wks. Our results demonstrate that the majority of the components of GH/IGF-I, SST/CORT and ghrelin systems are locally expressed in mouse MFP. Expression of elements of the GH/IGF-I axis was significantly increased in MFPs of HF-fed control mice while lack of endogenous SST partially suppressed, and lack of CORT completely blunted, the up-regulation observed in obese WT-controls. Since SST/CORT are known to exert an inhibitory role on the GH/IGFI axis, the increase in SST/CORT-receptor sst2 expression in MFPs of HF-fed CORT- and SST-KOs together with an elevation on circulating SST in CORT-KOs could explain the differences observed. These results offer new information on the factors (GH/IGF-I axis involved in the endocrine/metabolic dysregulation of MFPs in obesity, and suggest that CORT is not a mere SST sibling in regulating MG physiology.

  4. Short-term strength training and the expression of myostatin and IGF-I isoforms in rat muscle and tendon: differential effects of specific contraction types.

    Science.gov (United States)

    Heinemeier, K M; Olesen, J L; Schjerling, P; Haddad, F; Langberg, H; Baldwin, K M; Kjaer, M

    2007-02-01

    In skeletal muscle, an increased expression of insulin like growth factor-I isoforms IGF-IEa and mechano-growth factor (MGF) combined with downregulation of myostatin is thought to be essential for training-induced hypertrophy. However, the specific effects of different contraction types on regulation of these factors in muscle are still unclear, and in tendon the functions of myostatin, IGF-IEa, and MGF in relation to training are unknown. Female Sprague-Dawley rats were subjected to 4 days of concentric, eccentric, or isometric training (n = 7-9 per group) of the medial gastrocnemius, by stimulation of the sciatic nerve during general anesthesia. mRNA levels for myostatin, IGF-IEa, and MGF in muscle and Achilles' tendon were measured by real-time RT-PCR. Muscle myostatin mRNA decreased in response to all types of training (2- to 8-fold) (P effect of eccentric training was greater than concentric and isometric training (P tendon, myostatin mRNA was detected, but no changes were seen after exercise. IGF-IEa and MGF increased in muscle (up to 15-fold) and tendon (up to 4-fold) in response to training (P tendon no difference was seen between training types, but in muscle the effect of eccentric training was greater than concentric training for both IGF-IEa and MGF (P effect than concentric (P tendon to training, and the combined changes in myostatin and IGF-IEa/MGF expression could explain the important effect of eccentric actions for muscle hypertrophy.

  5. Clinical significance of measurement of changes of plasma NPY, CGRP and serum IGF-I levels in patients with acute cerebral infarction

    International Nuclear Information System (INIS)

    Deng Weiqun; Zhao Yushan

    2007-01-01

    Objective: To investigate the clinical significance of changes of plasma NPY, CGRP and serum IGF-I levels in patients with acute cerebral infarction. Methods: Plasma NPY, CGRP and serum IGF-I levels were determined with RIA in 32 patients with acute cerebral infarction both before and after treatment and 30 controls. Results: Before treatment plasma NPY levels were significantly higher (P<0.01) than those in the controls, while plasma CGRP and serum IGF-I levels were lower than those in controls (P<0.01). After treatment, plasma NPY levels decreased significantly (vs before treatment P<0.05), and plasma CGRP and serum IGF-I levels increased (P<0.05). Conclusion: Changes of plasma NPY, CGRP and serum IGF-I levels were closely related to the disease process in patients with acute cerebral infarction, determination of which was of important clinical values. (authors)

  6. The Fyn tyrosine kinase binds Irs-1 and forms a distinct signaling complex during insulin stimulation.

    Science.gov (United States)

    Sun, X J; Pons, S; Asano, T; Myers, M G; Glasheen, E; White, M F

    1996-05-03

    Irs-proteins link the receptors for insulin/IGF-1, growth hormones, and several interleukins and interferons to signaling proteins that contain Src homology-2 (SH2). To identify new Irs-1-binding proteins, we screened a mouse embryo expression library with recombinant [32P]Irs-1, which revealed a specific association between p59fyn and Irs-1. The SH2 domain in p59fyn bound to phosphorylated Tyr895 and Tyr1172, which are located in YXX(L/I) motifs. Mutation of p59fyn at the COOH-terminal tyrosine phosphorylation site (Tyr531) enhanced its binding to Irs-1 during insulin stimulation. Binding experiments with various SH2 protein revealed that Grb-2 was largely excluded from Irs-1 complexes containing p59fyn, whereas Grb-2 and p85 occurred in the same Irs-1 complex. By comparison with the insulin receptor, p59fyn kinase phosphorylated a unique cohort of tyrosine residues in Irs-1. These results outline a role for p59fyn or other related Src-kinases during insulin and cytokine signaling.

  7. High serum levels of growth hormone (GH) and insulin-like growth factor-I (IGF-I) during high-dose GH treatment in short children born small for gestational age

    NARCIS (Netherlands)

    M. van Dijk (Marije); P.G.H. Mulder (Paul); E.C.A.M. Houdijk (Mieke); J.C. Mulder (Jaap); K. Noordam (Kees); R.J.H. Odink (Roelof); C. Rongen-Westerlaken (Ciska); P.G. Voorhoeve (Paul); J.J.J. Waelkens (Johan); W.H. Stokvis-Brantsma; A.C.S. Hokken-Koelega (Anita)

    2006-01-01

    textabstractContext: Epidemiological studies have indicated that high serum levels of GH and IGF-I are associated with long-term risks. Objective: The objective of the study was to evaluate the changes in serum levels of GH during overnight profiles, IGF-I, and IGF binding protein 3 (IGFBP-3) in

  8. Autophagy resolves early retinal inflammation in Igf1-deficient mice

    Directory of Open Access Journals (Sweden)

    Ana I. Arroba

    2016-09-01

    Full Text Available Insulin-like growth factor-1 (IGF-1 is a growth factor with differentiating, anti-apoptotic and metabolic functions in the periphery, and anti-inflammatory properties in the nervous system. Mice that have mutations in the Igf1 gene, rendering the gene product inactive (Igf1−/−, present with age-related visual loss accompanied by structural alterations in the first synapses of the retinal pathway. Recent advances have revealed a crucial role of autophagy in immunity and inflammation. Keeping in mind this close relationship, we aimed to decipher these processes in the context of the defects that occur during ageing in the retina of Igf1−/− mice. Tnfa and Il1b mRNAs, and phosphorylation of JNK and p38 MAPK were elevated in the retinas of 6- and 12-month old Igf1−/− mice compared to those in age-matched Igf1+/+ controls. In 6-month-old Igf1−/− retinas, increased mRNA levels of the autophagy mediators Becn1, Atg9, Atg5 and Atg4, decreased p62 (also known as SQSTM1 protein expression together with an increased LC3-II:LC3-I ratio reflected active autophagic flux. However, in retinas from 12-month-old Igf1−/− mice, Nlrp3 mRNA, processing of the IL1β pro-form and immunostaining of active caspase-1 were elevated compared to those in age-matched Igf1+/+ controls, suggesting activation of the inflammasome. This effect concurred with accumulation of autophagosomes and decreased autophagic flux in the retina. Microglia localization and status of activation in the retinas of 12-month-old Igf1+/+ and Igf1−/− mice, analyzed by immunostaining of Cd11b and Iba-1, showed a specific distribution pattern in the outer plexiform layer (OPL, inner plexiform layer (IPL and inner nuclear layer (INL, and revealed an increased number of activated microglia cells in the retina of 12-month-old blind Igf1−/− mice. Moreover, reactive gliosis was exclusively detected in the retinas from 12-month-old blind Igf1−/− mice. In conclusion, this study

  9. Alternative splicing and expression of the insulin-like growth factor (IGF-1) gene in osteoblasts under mechanical stretch

    Institute of Scientific and Technical Information of China (English)

    XIAN Chengyu; WANG Yuanliang; ZHANG Bingbing; TANG Liling; PAN Jun; LUO Yanfeng; JIANG Peng; LI Dajun

    2006-01-01

    Insulin-like growth factor 1 (IGF-1) promotes osteoblasts differentiation and bone formation,and its expression is induced by mechanical stretch,thus IGF-1 has been considered an effector molecule that links mechanical stimulation and local tissue responses. In this study, a mechanical stretching device was designed to apply physiological level static or cyclic stretching stimulation to osteoblasts.Different isoforms of IGF-1 mRNA were amplified by RT-PCR from the cells using respective primers and these amplified products were sequenced. An isoform of IGF-1 splicing product was found to be selectively produced by osteoblasts under stretching stimulation. This IGF-1 isoform had identical sequence with the mechano growth factor (MGF) which was originally identified in muscle cells. Regulations of the expression of the liver-type IGF (L.IGF-1) and MGF in osteoblasts under stretch stimulation were further studied using semi-quantitative RT-PCR.Stretch stimulation was found to promot the expression of IGF-1 (L.IGF-1 and MGF), and for both isoforms expression was more effectively stimulated by cyclic stretch than static stretch. MGF was detected only in osteoblasts subjected to mechanical stretch,suggesting MGF was a stretch sensitive growth factor.Expression of MGF peaked earlier than that of L.IGF-1, which was similar to their regulation in muscie and suggested similar roles of MGF and L.IGF-1in bone as in muscle cells. The functions of MGF and L.IGF-1 in osteoblasts shall be established by further experimental studies.

  10. Longitudinal infusion of a complex of insulin-like growth factor-I and IGF-binding protein-3 in five preterm infants: pharmacokinetics and short-term safety.

    Science.gov (United States)

    Ley, David; Hansen-Pupp, Ingrid; Niklasson, Aimon; Domellöf, Magnus; Friberg, Lena E; Borg, Jan; Löfqvist, Chatarina; Hellgren, Gunnel; Smith, Lois E H; Hård, Anna-Lena; Hellström, Ann

    2013-01-01

    In preterm infants, low levels of insulin-like growth factor-I (IGF-I) and IGF binding protein 3 (IGFBP-3) are associated with impaired brain growth and retinopathy of prematurity (ROP). Treatment with IGF-I/IGFBP-3 may be beneficial for brain development and may decrease the prevalence of ROP. In a phase II pharmacokinetics and safety study, five infants (three girls) with a median (range) gestational age (GA) of 26 wk + 6 d (26 wk + 0 d to 27 wk + 2 d) and birth weight of 990 (900-1,212) g received continuous intravenous infusion of recombinant human (rh)IGF-I/rhIGFBP-3. Treatment was initiated during the first postnatal day and continued for a median (range) duration of 168 (47-168) h in dosages between 21 and 111 µg/kg/24 h. Treatment with rhIGF-I/rhIGFBP-3 was associated with higher serum IGF-I and IGFBP-3 concentrations (P model-predicted endogenous levels. Of 74 IGF-I samples measured during study drug infusion, 37 (50%) were within the target range, 4 (5%) were above, and 33 (45%) were below. The predicted dose of rhIGF-I/rhIGFBP-3 required to establish circulating levels of IGF-I within the intrauterine range in a 1,000 g infant was 75-100 µg/kg/24 h. No hypoglycemia or other adverse effects were recorded. In this study, continuous intravenous infusion of rhIGF-I/rhIGFBP-3 was effective in increasing serum concentrations of IGF-I and IGFBP-3, and was found to be safe.

  11. Phosphorylation of varicella-zoster virus glycoprotein gpI by mammalian casein kinase II and casein kinase I

    International Nuclear Information System (INIS)

    Grose, C.; Jackson, W.; Traugh, J.A.

    1989-01-01

    Varicella-zoster virus (VZV) glycoprotein gpI is the predominant viral glycoprotein within the plasma membranes of infected cells. This viral glycoprotein is phosphorylated on its polypeptide backbone during biosynthesis. In this report, the authors investigated the protein kinases which participate in the phosphorylation events. Under in vivo conditions, VZV gpI was phosphorylated on its serine and threonine residues by protein kinases present within lysates of either VZV-infected or uninfected cells. Because this activity was diminished by heparin, a known inhibitor of casein kinase II, isolated gpI was incubated with purified casein kinase II and shown to be phosphorylated in an in vitro assay containing [γ- 32 P]ATP. The same glycoprotein was phosphorylated when [ 32 P]GTP was substituted for [ 32 P]ATP in the protein kinase assay. They also tested whether VZV gpI was phosphorylated by two other ubiquitous mammalian protein kinases--casein kinase I and cyclic AMP-dependent kinase--and found that only casein kinase I modified gpI. When the predicted 623-amino-acid sequence of gpI was examined, two phosphorylation sites known to be optimal for casein kinase II were observed. In summary, this study showed that VZV gpI was phosphorylated by each of two mammalian protein kinases (casein kinase I and casein kinase II) and that potential serine-threonine phosphorylation sites for each of these two kinases were present in the viral glycoprotein

  12. IGF-1 and insulin as growth hormones.

    Science.gov (United States)

    Laron, Zvi

    2004-01-01

    IGF-1 generated in the liver is the anabolic effector and linear growth promoting hormone of the pituitary growth hormone (GH). This is evidenced by dwarfism in states of congenital IGF-1 deficiency, Igf1 gene mutation/deletions or knockouts, and in Laron syndrome (LS), due to GH receptor gene mutations/deletions or IGF-1 receptor blocking. In a positive way, daily IGF-1 administration to stunted patients with LS or hGH gene deletion accelerates linear growth velocity. IGF-1 acts on the proliferative cells of the epiphyseal cartilage. IGF-1 also induces organ and tissue growth; its absence causing organomicria. Insulin shares a common ancestry with IGF-1 and with 45% amino acid homology, as well as very close relationships in the structure of its receptors and post-receptor cascade, also acts as a growth hormone. It has protein anabolic activity and stimulates IGF-1 synthesis. Pancreas agenesis causes short babies, and obese children with hyperinsulinism, with or without pituitary GH, have an accelerated growth rate and skeletal maturation; so do babies with macrosomia. Whether the insulin growth effect is direct, or mediated by IGF-1 or leptin is controversial.

  13. Overexpression of IGF-I receptor in HeLa cells enhances in vivo radioresponse

    International Nuclear Information System (INIS)

    Kaneko, Haruna; Yu, Dong; Miura, Masahiko

    2007-01-01

    Insulin-like growth factor I receptor (IGF-IR) is a transmembrane receptor tyrosine kinase whose activation strongly promotes cell growth and survival. We previously reported that IGF-IR activity confers intrinsic radioresistance in mouse embryo fibroblasts in vitro. However, it is still unclear whether tumor cells overexpressing IGF-IR exhibit radioresistance in vivo. For this purpose, we established HeLa cells that overexpress IGF-IR (HeLa-R), subcutaneously transplanted these cells into nude mice, and examined radioresponse in the resulting solid tumors. HeLa-R cells exhibited typical in vitro phenotypes generally observed in IGF-IR-overexpressing cells, as well as significant intrinsic radioresistance in vitro compared with parent cells. As expected, the transplanted HeLa-R tumors grew at a remarkably higher rate than parent tumors. Histological analysis revealed that HeLa-R tumors expressed more VEGF and had a higher density of tumor vessels. Unexpectedly, a marked growth delay was observed in HeLa-R tumors following 10 Gy of X-irradiation. Immunostaining of HeLa-R tumors for the hypoxia marker pimonidazole revealed a significantly lower level of hypoxic cells. Moreover, clamp hypoxia significantly increased radioresistance in HeLa-R tumors. Tumor microenvironments in vivo generated by the IGF-IR expression thus could be a major factor in determining the tumor radioresponse in vivo

  14. Aging and oxidative stress reduce the response of human articular chondrocytes to insulin-like growth factor 1 and osteogenic protein 1.

    Science.gov (United States)

    Loeser, Richard F; Gandhi, Uma; Long, David L; Yin, Weihong; Chubinskaya, Susan

    2014-08-01

    To determine the effects of aging and oxidative stress on the response of human articular chondrocytes to insulin-like growth factor 1 (IGF-1) and osteogenic protein 1 (OP-1). Chondrocytes isolated from normal articular cartilage obtained from tissue donors were cultured in alginate beads or monolayer. Cells were stimulated with 50-100 ng/ml of IGF-1, OP-1, or both. Oxidative stress was induced using tert-butyl hydroperoxide. Sulfate incorporation was used to measure proteoglycan synthesis, and immunoblotting of cell lysates was performed to analyze cell signaling. Confocal microscopy was performed to measure nuclear translocation of Smad4. Chondrocytes isolated from the articular cartilage of tissue donors ranging in age from 24 years to 81 years demonstrated an age-related decline in proteoglycan synthesis stimulated by IGF-1 and IGF-1 plus OP-1. Induction of oxidative stress inhibited both IGF-1- and OP-1-stimulated proteoglycan synthesis. Signaling studies showed that oxidative stress inhibited IGF-1-stimulated Akt phosphorylation while increasing phosphorylation of ERK, and that these effects were greater in cells from older donors. Oxidative stress also increased p38 phosphorylation, which resulted in phosphorylation of Smad1 at the Ser(206) inhibitory site and reduced nuclear accumulation of Smad1. Oxidative stress also modestly reduced OP-1-stimulated nuclear translocation of Smad4. These results demonstrate an age-related reduction in the response of human chondrocytes to IGF-1 and OP-1, which are 2 important anabolic factors in cartilage, and suggest that oxidative stress may be a contributing factor by altering IGF-1 and OP-1 signaling. Copyright © 2014 by the American College of Rheumatology.

  15. [Differential expression of IGF-I and its mRNA in mandibular condylar cartilage of rat--direct evidence for servosystem theory of facial growth].

    Science.gov (United States)

    Zhou, Z; Luo, S

    1998-05-01

    It was studied the expression of IGF-I and its mRNA in the condylar cartilage of 10 7-week-old SD male rats by using in situ hybridization and immunohisto-chemistry technique. The results showed both IGF-I and its gene expressed in growing rat condyle. IGF-I peptide was abundant in germinal zone, and positive reaction of its mRNA was strongest in transitional and maturational zones. These indicate that condylar cartilage has the capability of local production and secretion of IGF-I, mediating the command effect of STH, and differential expression of IGF-I and its mRNA might establish the local feedback loop, which supply a direct evidence for servosystem theory of facial growth.

  16. Circulating IGF1 regulates hippocampal IGF1 levels and brain gene expression during adolescence

    OpenAIRE

    Yan, Han; Mitschelen, Matthew; Bixler, Georgina V; Brucklacher, Robert M; Farley, Julie A; Han, Song; Freeman, Willard M; Sonntag, William E

    2011-01-01

    GH and its anabolic mediator, IGF1, are important not only in somatic growth but also in the regulation of brain function. Even though GH treatment has been used clinically to improve body composition and exercise capacity in adults, its influence on central nervous system function has only recently been recognized. This is also the case for children with childhood-onset GH deficiency (GHD) where GH has been used to stimulate bone growth and enhance final adult height. Circulating IGF1 is tra...

  17. IGF binding proteins.

    Science.gov (United States)

    Bach, Leon A

    2017-12-18

    Insulin-like growth factor binding proteins (IGFBPs) 1-6 bind IGFs but not insulin with high affinity. They were initially identified as serum carriers and passive inhibitors of IGF actions. However, subsequent studies showed that, although IGFBPs inhibit IGF actions in many circumstances, they may also potentiate these actions. IGFBPs are widely expressed in most tissues, and they are flexible endocrine and autocrine/paracrine regulators of IGF activity, which is essential for this important physiological system. More recently, individual IGFBPs have been shown to have IGF-independent actions. Mechanisms underlying these actions include (i) interaction with non-IGF proteins in compartments including the extracellular space and matrix, the cell surface and intracellularly; (ii) interaction with and modulation of other growth factor pathways including EGF, TGF- and VEGF; and (iii) direct or indirect transcriptional effects following nuclear entry of IGFBPs. Through these IGF-dependent and IGF-independent actions, IGFBPs modulate essential cellular processes including proliferation, survival, migration, senescence, autophagy and angiogenesis. They have been implicated in a range of disorders including malignant, metabolic, neurological and immune diseases. A more complete understanding of their cellular roles may lead to the development of novel IGFBP-based therapeutic opportunities.

  18. The IGF-I/JAK2-STAT3/miR-21 signaling pathway may be associated with human renal cell carcinoma cell growth.

    Science.gov (United States)

    Su, Ying; Zhao, An; Cheng, Guoping; Xu, Jingjing; Ji, Enming; Sun, Wenyong

    2017-07-04

    Renal cell carcinoma (RCC) is the highest mortality rate of the genitourinary cancers, and the treatment options are very limited. Thus, identification of molecular mechanisms underlying RCC tumorigenesis, is critical for identifying biomarkers for RCC diagnosis and prognosis. To validate whether the IGF-I/JAK2-STAT3/miR-21 signaling pathway is associated with human RCC cell growth. qRT-PCR and Western blotting were used to detect the mRNA and protein expression levels, respectively. The MTT assay was performed to determine cell survival rate. The Annexin V-FITC/PI apoptosis detection kit was used to detect cell apoptosis. We employed RCC tissues and cell lines (A498; ACHN; Caki-1; Caki-2 and 786-O) in the study. IGF-I, and its inhibitor (NT-157) were administrated to detect the effects of IGF-I on the expression of miR-21 and p-JAK2. JAK2 inhibitor (AG490), and si-STAT3 were used to detect the effects of JAK2/STAT3 signaling pathway on the expression of miR-21. In our study, we firstly showed that the expression levels of IGF-I and miR-21 were up-regulated in RCC tissues and cell lines. After exogenous IGF-I treatment, the expression levels of miR-21, p-IGF-IR and p-JAK2 were significantly increased, whereas NT-157 treatment showed the reversed results. Further study indicated that JAK2 inhibitor or si-STAT3 significantly reversed the IGF-I-induced miR-21 expression level. Finally, we found that IGF-I treatment significantly prompted human RCC cell survival and inhibited cell apoptosis, and NT-157 treatment showed the reversed results. The IGF-I/JAK2-STAT3/miR-21 signaling pathway may be associated with human RCC cell growth.

  19. IGF-1-induced MMP-11 expression promotes the proliferation and invasion of gastric cancer cells through the JAK1/STAT3 signaling pathway.

    Science.gov (United States)

    Su, Chao; Wang, Wenchang; Wang, Cunchuan

    2018-05-01

    The present study aimed to investigate the association between insulin-like growth factor-1 (IGF-1) and matrix metalloproteinase-11 (MMP-11) expression in gastric cancer (GC) and the underlying mechanisms in SGC-7901 cells. Reverse transcription-quantitative polymerase chain reaction analysis revealed that the expression of IGF-1 and MMP-11 was significantly upregulated in GC tissues compared with normal gastric tissue. Furthermore, IGF-1 significantly and dose-dependently promoted MMP-11. Western blotting revealed that the addition of IGF-1 to SGC-7901 cells led to an evident enhancement in signal transducer and activator of transcription 3 (STAT3), IGF-1R and Janus kinase 1 (JAK1) phosphorylation at 20 and 40 min. A decrease in the extent of the elevated expression of MMP-11 and the enhanced phosphorylation of STAT3, JAK1 and IGF-1 receptor (IGF-1R) induced by IGF-1 in SGC-7901 cells were observed following treatment with NT157 (an IGF-1R inhibitor). Furthermore, piceatannol (a JAK1 inhibitor) or small interfering RNA against STAT3 reduced the extent of the increased expression of MMP-11 induced by IGF-1 in SGC-7901 cells. Piceatannol treatment induced the dose-dependent decline in the enhancement of STAT3 phosphorylation induced by IGF-1, indicating that the JAK1/STAT3 pathway may be implicated in the elevated expression of MMP-11 induced by IGF-1 in SGC-7901 cells. Finally, IGF-1 treatment significantly promoted the proliferation and invasion of SGC-7901 cells, which was inhibited following NT157, piceatannol or si-STAT3 treatment. The present study therefore demonstrated that IGF-1-induced MMP-11 may have facilitated the proliferation and invasion of SGC-7901 cells via the JAK1/STAT3 pathway.

  20. Higher Maternal Protein Intake during Pregnancy Is Associated with Lower Cord Blood Concentrations of Insulin-like Growth Factor (IGF)-II, IGF Binding Protein 3, and Insulin, but Not IGF-I, in a Cohort of Women with High Protein Intake.

    Science.gov (United States)

    Switkowski, Karen M; Jacques, Paul F; Must, Aviva; Hivert, Marie-France; Fleisch, Abby; Gillman, Matthew W; Rifas-Shiman, Sheryl; Oken, Emily

    2017-07-01

    Background: Prenatal exposure to dietary protein may program growth-regulating hormones, consequently influencing early-life growth patterns and later risk of associated chronic diseases. The insulin-like growth factor (IGF) axis is of particular interest in this context given its influence on pre- and postnatal growth and its sensitivity to the early nutritional environment. Objective: Our objective was to examine associations of maternal protein intake during pregnancy with cord blood concentrations of IGF-I, IGF-II, IGF binding protein-3 (IGFBP-3), and insulin. Methods: We studied 938 mother-child pairs from early pregnancy through delivery in the Project Viva cohort. Using multivariable linear regression models adjusted for maternal race/ethnicity, education, income, smoking, parity, height, and gestational weight gain and for child sex, we examined associations of second-trimester maternal protein intake [grams per kilogram (weight before pregnancy) per day], as reported on a food frequency questionnaire, with IGF-I, IGF-II, IGFBP-3, and insulin concentrations in cord blood. We also examined how these associations may differ by child sex and parity. Results: Mothers were predominantly white (71%), college-educated (64%), and nonsmokers (67%). Mean ± SD protein intake was 1.35 ± 0.35 g ⋅ kg -1 ⋅ d -1 Each 1-SD increment in second-trimester protein intake corresponded to a change of -0.50 ng/mL (95% CI: -2.26, 1.26 ng/mL) in IGF-I and -0.91 μU/mL (95% CI: -1.45, -0.37 μU/mL) in insulin. Child sex and parity modified associations of maternal protein intake with IGF-II and IGFBP-3: protein intake was inversely associated with IGF-II in girls ( P -interaction = 0.04) and multiparous mothers ( P -interaction = 0.05), and with IGFBP-3 in multiparous mothers ( P -interaction = 0.04). Conclusions: In a cohort of pregnant women with relatively high mean protein intakes, higher intake was associated with lower concentrations of growth-promoting hormones in cord

  1. Contraction regulates site-specific phosphorylation of TBC1D1 in skeletal muscle.

    Science.gov (United States)

    Vichaiwong, Kanokwan; Purohit, Suneet; An, Ding; Toyoda, Taro; Jessen, Niels; Hirshman, Michael F; Goodyear, Laurie J

    2010-10-15

    TBC1D1 (tre-2/USP6, BUB2, cdc16 domain family member 1) is a Rab-GAP (GTPase-activating protein) that is highly expressed in skeletal muscle, but little is known about TBC1D1 regulation and function. We studied TBC1D1 phosphorylation on three predicted AMPK (AMP-activated protein kinase) phosphorylation sites (Ser231, Ser660 and Ser700) and one predicted Akt phosphorylation site (Thr590) in control mice, AMPKα2 inactive transgenic mice (AMPKα2i TG) and Akt2-knockout mice (Akt2 KO). Muscle contraction significantly increased TBC1D1 phosphorylation on Ser231 and Ser660, tended to increase Ser700 phosphorylation, but had no effect on Thr590. AICAR (5-aminoimidazole-4-carboxyamide ribonucleoside) also increased phosphorylation on Ser231, Ser660 and Ser700, but not Thr590, whereas insulin only increased Thr590 phosphorylation. Basal and contraction-stimulated TBC1D1 Ser231, Ser660 and Ser700 phosphorylation were greatly reduced in AMPKα2i TG mice, although contraction still elicited a small increase in phosphorylation. Akt2 KO mice had blunted insulin-stimulated TBC1D1 Thr590 phosphorylation. Contraction-stimulated TBC1D1 Ser231 and Ser660 phosphorylation were normal in high-fat-fed mice. Glucose uptake in vivo was significantly decreased in tibialis anterior muscles overexpressing TBC1D1 mutated on four predicted AMPK phosphorylation sites. In conclusion, contraction causes site-specific phosphorylation of TBC1D1 in skeletal muscle, and TBC1D1 phosphorylation on AMPK sites regulates contraction-stimulated glucose uptake. AMPK and Akt regulate TBC1D1 phosphorylation, but there must be additional upstream kinases that mediate TBC1D1 phosphorylation in skeletal muscle.

  2. Parathyroid hormone blocks the stimulatory effect of insulin-like growth factor-I on collagen synthesis in cultured 21-day fetal rat calvariae

    International Nuclear Information System (INIS)

    Kream, B.E.; Petersen, D.N.; Raisz, L.G.

    1990-01-01

    We examined the interaction of parathyroid hormone (PTH) and recombinant human insulin-like growth factor I (IGF-I) on collagen synthesis in 21-day fetal rat calvariae as assessed by measuring the incorporation of [ 3 H]proline into collagenase-digestible protein. After 96 hours of culture, 10 nM PTH antagonized the stimulation of collagen synthesis and partially blocked the increase in dry weight produced by 10 nM IGF-I. The effect of PTH to block IGF-I stimulated collagen synthesis was observed in the central bone of calvariae and was mimicked by forskolin and phorbol 12-myristate 13-acetate, but not by 1,25-dihydroxyvitamin D3, transforming growth factor-alpha or dexamethasone. Our data are consistent with the concept that the direct effect of PTH is to inhibit basal CDP labeling and fully oppose IGF-I stimulated CDP labeling. The finding that this effect of PTH is mimicked by forskolin and PMA suggests that this block in IGF-I stimulation of CDP labeling involves both cAMP and protein kinase C mediated pathways

  3. IGF-I generation test in prepubertal children with Noonan syndrome due to mutations in the PTPN11 gene.

    Science.gov (United States)

    Bertelloni, Silvano; Baroncelli, Giampiero I; Dati, Eleonora; Ghione, Silvia; Baldinotti, Fulvia; Toschi, Benedetta; Simi, Paolo

    2013-01-01

    Short stature represents one of the main features of children with Noonan syndrome. The reason for impaired growth remains largely unknown. To assess GH and IGF1 secretion in children with Noonan syndrome. 12 prepubertal children with Noonan syndrome due to mutations in the PTPN11 gene [7 males, 6 females; median age, years: 8.6 (range 5.1-13.4)] were studied; 12 prepubertal children with short stature (SS) [7 males, 5 females; median age, years: 8.1 (range 4.8-13.1)] served as the control group. GH secretion after arginine stimulation test; IGF1 generation test by measurement of IGF1 levels before and after recombinant GH (rGH) administration (0.05 mg/kg/day for 4 days). Baseline and stimulated peak values of GH were not significantly different between the two groups. At +120 minutes, GH levels remained significantly higher (p = 0.0121) in comparison with baseline values in children with Noonan syndrome. Baseline IGFI levels in patients and in SS controls were not significantly different, in contrast to values after the rGH generation test [205 ng/mL (interquartiles 138.2-252.5 ng/mL) and 284.5 ng/mL (interquartiles 172-476 ng/mL), respectively; p = 0.0248]. IGF1 values were significantly related to height (baseline: r = 773, p = 0.0320; peak: r = 0.591, p = 0.0428) in children with Noonan syndrome. Blunted increase of IGF1 after the rGH generation test was present in children with Noonan syndrome due to mutations in the PTPN11 gene in comparison with SS children. This finding may be due to partial GH resistance in the former likely related to altered Ras-MAPK signaling pathway.

  4. Serum concentrations of free and total insulin-like growth factor-I, IGF binding proteins -1 and -3 and IGFBP-3 protease activity in boys with normal or precocious puberty

    DEFF Research Database (Denmark)

    Juul, A; Flyvbjerg, Allan; Frystyk, Jan

    1996-01-01

    Circulating IGF-I and IGF binding protein-3 (IGFBP-3) levels both increase in puberty where growth velocity is high. The amount of free IGF-I is dependent on the IGF-I level and on the concentrations of the specific IGFBPs. Furthermore, IGFBP-3 proteolysis regulates the bioavailability of IGF......-I. However, the concentration of free IGF-I and possible IGFBP-3 proteolytic activity in puberty has not previously been studied....

  5. High-intensity interval training (HIIT) increases insulin-like growth factor-I (IGF-I) in sedentary aging men but not masters' athletes: an observational study.

    Science.gov (United States)

    Herbert, Peter; Hayes, Lawrence D; Sculthorpe, Nicholas; Grace, Fergal M

    2017-03-01

    The aim of this investigation was to examine the impact high-intensity interval training (HIIT) on serum insulin-like growth factor-I (IGF-I) in active compared with sedentary aging men. 22 lifetime sedentary (SED; 62 ± 2 years) and 17 masters' athletes (LEX; 60 ± 5 years) were recruited to the study. As HIIT requires preconditioning exercise in sedentary cohorts, the study required three assessment phases; enrollment (phase A), following preconditioning exercise (phase B), and post-HIIT (phase C). Serum IGF-I was determined by electrochemiluminescent immunoassay. IGF-I was higher in LEX compared to SED at baseline (p = 0.007, Cohen's d = 0.91), and phase B (p = 0.083, Cohen's d = 0.59), with only a small difference at C (p = 0.291, Cohen's d = 0.35). SED experienced a small increase in IGF-I following preconditioning from 13.1 ± 4.7 to 14.2 ± 6.0 μg·dl -1 (p = 0.376, Cohen's d = 0.22), followed by a larger increase post-HIIT (16.9 ± 4.4 μg·dl -1 ), which was significantly elevated compared with baseline (p = 0.002, Cohen's d = 0.85), and post-preconditioning (p = 0.005, Cohen's d = 0.51). LEX experienced a trivial changes in IGF-I from A to B (18.2 ± 6.4 to 17.2 ± 3.7 μg·dl -1 [p = 0.538, Cohen's d = 0.19]), and a small change post-HIIT (18.4 ± 4.1 μg·dl -1 [p = 0.283, Cohen's d = 0.31]). Small increases were observed in fat-free mass in both groups following HIIT (p HIIT with preconditioning exercise abrogates the age associated difference in IGF-I between SED and LEX, and induces small improvements in fat-free mass in both SED and LEX.

  6. Treatment with N- and C-Terminal Peptides of Parathyroid Hormone-Related Protein Partly Compensate the Skeletal Abnormalities in IGF-I Deficient Mice

    Science.gov (United States)

    Portal-Núñez, Sergio; Murillo-Cuesta, Silvia; Lozano, Daniel; Cediel, Rafael; Esbrit, Pedro

    2014-01-01

    Insulin-like growth factor-I (IGF-I) deficiency causes growth delay, and IGF-I has been shown to partially mediate bone anabolism by parathyroid hormone (PTH). PTH-related protein (PTHrP) is abundant in bone, and has osteogenic features by poorly defined mechanisms. We here examined the capacity of PTHrP (1–36) and PTHrP (107–111) (osteostatin) to reverse the skeletal alterations associated with IGF-I deficiency. Igf1-null mice and their wild type littermates were treated with each PTHrP peptide (80 µg/Kg/every other day/2 weeks; 2 males and 4 females for each genotype) or saline vehicle (3 males and 3 females for each genotype). We found that treatment with either PTHrP peptide ameliorated trabecular structure in the femur in both genotypes. However, these peptides were ineffective in normalizing the altered cortical structure at this bone site in Igf1-null mice. An aberrant gene expression of factors associated with osteoblast differentiation and function, namely runx2, osteoprotegerin/receptor activator of NF-κB ligand ratio, Wnt3a , cyclin D1, connexin 43, catalase and Gadd45, as well as in osteocyte sclerostin, was found in the long bones of Igf1-null mice. These mice also displayed a lower amount of trabecular osteoblasts and osteoclasts in the tibial metaphysis than those in wild type mice. These alterations in Igf1-null mice were only partially corrected by each PTHrP peptide treatment. The skeletal expression of Igf2, Igf1 receptor and Irs2 was increased in Igf1-null mice, and this compensatory profile was further improved by treatment with each PTHrP peptide related to ERK1/2 and FoxM1 activation. In vitro, PTHrP (1–36) and osteostatin were effective in promoting bone marrow stromal cell mineralization in normal mice but not in IGF-I-deficient mice. Collectively, these findings indicate that PTHrP (1–36) and osteostatin can exert several osteogenic actions even in the absence of IGF-I in the mouse bone. PMID:24503961

  7. Stimulation of liver IGF-1 expression promotes peak bone mass achievement in growing rats: a study with pomegranate seed oil.

    Science.gov (United States)

    Bachagol, Deepa; Joseph, Gilbert Stanley; Ellur, Govindraj; Patel, Kalpana; Aruna, Pamisetty; Mittal, Monika; China, Shyamsundar Pal; Singh, Ravendra Pratap; Sharan, Kunal

    2018-02-01

    Peak bone mass (PBM) achieved at adulthood is a strong determinant of future onset of osteoporosis, and maximizing it is one of the strategies to combat the disease. Recently, pomegranate seed oil (PSO) has been shown to have bone-sparing effect in ovariectomized mice. However, its effect on growing skeleton and its molecular mechanism remain unclear. In the present study, we evaluated the effect of PSO on PBM in growing rats and associated mechanism of action. PSO was given at various doses to 21-day-old growing rats for 90 days by oral gavage. The changes in bone parameters were assessed by micro-computed tomography and histology. Enzyme-linked immunosorbent assay was performed to analyze the levels of serum insulin-like growth factor type 1 (IGF-1). Western blotting from bone and liver tissues was done. Chromatin immunoprecipitation assay was performed to study the histone acetylation levels at IGF-1 gene. The results of the study show that PSO treatment significantly increases bone length, bone formation rate, biomechanical parameters, bone mineral density and bone microarchitecture along with enhancing muscle and brown fat mass. This effect was due to the increased serum levels of IGF-1 and stimulation of its signaling in the bones. Studies focusing on acetylation of histones in the liver, the major site of IGF-1 synthesis, showed enrichment of acetylated H3K9 and H3K14 at IGF-1 gene promoter and body. Further, the increased acetylation at H3K9 and H3K14 was associated with a reduced HDAC1 protein level. Together, our data suggest that PSO promotes the PBM achievement via increased IGF-1 expression in liver and IGF-1 signaling in bone. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Clinical significance of changes of serum Hcy and IGF-I levels after treatment in patients with acute cerebral infarction

    International Nuclear Information System (INIS)

    Wang Yuezhou

    2011-01-01

    Objective: To investigate the clinical significance of serum Hcy and IGF-I levels in patients with acute cerebral infarction. Methods: Serum IGF-I (with RIA), Hcy (with ELISA)levels were measured in 32 patients with acute cerebral infarction both before and after treatment as well as in 35 normal controls. Results: Before treatment, the serum Hcy level was remarkably higher than that in controls (P 0.05). Conclusion: The level of Hcy increased and IGF-I decreased in the patients with acute cerebral infarction which closely to the severity of acute cerebral infarction and may be taken as a sensitive biochemical indicator for predicting pathogenesis and progress of ACI. (authors)

  9. IGF-I at 9 and 36 months of age — relations with body composition and diet at 3 years — the SKOT cohort

    DEFF Research Database (Denmark)

    Ejlerskov, Katrine Tschentscher; Larnkjær, A.; Pedersen, D.

    2014-01-01

    Objective High infancy levels of insulin-like growth factor-I (IGF-I) have been associated with increased linear growth and fat-free mass (FFM) but also with risk of obesity. This paper examines how IGF-I at 9 and 36 months relates to diet and body composition. Design Healthy term infants from...... and values were considerably higher in girls (43%). Children breastfed at 9 months had lower IGF-I concentrations at 9 months but reached the same IGF-I concentrations at 36 months as infants not breastfed at 9 months. IGF-I at 36 months was positively associated with height, weight, BMI, predicted FFM...... and FFM index (FFM/height (kg/m2)). Although there also was a positive association with predicted fat mass (FM) there was no association with FM index (FM/height (kg/m2)). Further, a negative association with skin fold thickness was observed. A change in IGF-I from 9–36 months was positively related...

  10. Cross-talk between insulin and Wnt signaling in preadipocytes

    DEFF Research Database (Denmark)

    Palsgaard, Jane; Emanuelli, Brice; Winnay, Jonathon N

    2012-01-01

    and appears to be due to an inducible interaction between LRP5 and the insulin receptor as demonstrated by co-immunoprecipitation. These data demonstrate that Wnt and insulin signaling pathways exhibit cross-talk at multiple levels. Wnt induces phosphorylation of Akt, ERK1/2, and GSK3β, and this is dependent...... and LRP6 and with and without knock-out of insulin and IGF-1 receptors. We find that Wnt stimulation leads to phosphorylation of insulin signaling key mediators, including Akt, GSK3β, and ERK1/2, although with a lower fold stimulation and slower time course than observed for insulin. These Wnt effects...... are insulin/IGF-1 receptor-dependent and are lost in insulin/IGF-1 receptor double knock-out cells. Conversely, in LRP5 knockdown preadipocytes, insulin-induced phosphorylation of IRS1, Akt, GSK3β, and ERK1/2 is highly reduced. This effect is specific to insulin, as compared with IGF-1, stimulation...

  11. Pregnancy-induced increase in circulating IGF-I is associated with progression of diabetic retinopathy in women with type 1 diabetes

    DEFF Research Database (Denmark)

    Nielsen, Lene Ringholm; Vestgaard, Marianne; Laugesen, Caroline S

    2011-01-01

    To evaluate the influence of Insulin-like Growth factor-I (IGF-I) and Placental Growth Hormone (GH) on progression of diabetic retinopathy during pregnancy in women with type 1 diabetes.......To evaluate the influence of Insulin-like Growth factor-I (IGF-I) and Placental Growth Hormone (GH) on progression of diabetic retinopathy during pregnancy in women with type 1 diabetes....

  12. Insulin rapidly stimulates phosphorylation of a 46-kDa membrane protein on tyrosine residues as well as phosphorylation of several soluble proteins in intact fat cells

    International Nuclear Information System (INIS)

    Haering, H.U.; White, M.F.; Machicao, F.; Ermel, B.; Schleicher, E.; Obermaier, B.

    1987-01-01

    It is speculated that the transmission of an insulin signal across the plasma membrane of cells occurs through activation of the tyrosine-specific receptor kinase, autophosphorylation of the receptor, and subsequent phosphorylation of unidentified substrates in the cell. In an attempt to identify possible substrates, the authors labeled intact rat fat cells with [ 32 P]orthophosphate and used an antiphosphotyrosine antibody to identify proteins that become phosphorylated on tyrosine residues in an insulin-stimulated way. In the membrane fraction of the fat cells, they found, in addition to the 95-kDa β-subunit of the receptor, a 46-kDa phosphoprotein that is phosphorylated exclusively on tyrosine residues. This protein is not immunoprecipitated by antibodies against different regions of the insulin receptor and its HPLC tryptic peptide map is different from the tryptic peptide map of the insulin receptor, suggesting that it is not derived from the receptor β-subunit. Insulin stimulates the tyrosine phosphorylation of the 46-kDa protein within 150 sec in the intact cell 3- to 4-fold in a dose-dependent way at insulin concentrations between 0.5 nM and 100 nM. Insulin (0.5 nM, 100 nM) stimulated within 2 min the 32 P incorporation into a 116-kDa band, a 62 kDa band, and three bands between 45 kDa and 50 kDa 2- to 10-fold. They suggest that the 46-kDa membrane protein and possibly also the soluble proteins are endogenous substrates of the receptor tyrosine kinase in fat cells and that their phosphorylation is an early step in insulin signal transmission

  13. Insulin-like growth factors (IGFs) and IGF binding proteins in active Crohn’s disease treated with omega-3 or omega-6 fatty acids and corticosteroids

    DEFF Research Database (Denmark)

    Eivindson, Martin; Grønbæk, Henning; Nielsen, J.N.

    2005-01-01

    of the present study was to examine the effects of enteral nutrition, Impact Powder, as adjuvant therapy to corticosteroid treatment on changes in the GH/IGF-I axis in patients with Crohn's disease (CD). MATERIAL AND METHODS: The patients were randomized to 3-IP (omega-3-fatty acid (FA), 3 g/day) or 6-IP (omega...... with previously published studies and may be explained by corticosteroid treatment; however, we cannot exclude an additional effect of omega3-/omega6 FA as adjuvant enteral nutrition.......-6-FA, 9 g/day). Changes in total IGF-I (tIGF-I) and total IGF-II (tIGF-II), free IGF-I (fIGF-I), IGF binding proteins (IGFBP-1 and IGFBP-3), IGFBP-3 protease activity and insulin levels were examined in 31 patients with active CD (CDAI: 186-603) during treatment with prednisolone (40 mg for 1 week...

  14. Clinical diagnostic value of combined determination of serum tPSA, cPSA and IGF-I levels in patients with prostatic disorders

    International Nuclear Information System (INIS)

    Zhang Bashan; Zhang Zigang; Lai Fudi

    2008-01-01

    Objective: To investigate the diagnostic value of combined determination of serum total prostatic specific antigen (tPSA), complex prostatic specific antigen (cPSA) and IGF-I levels in patients with prostatic disorders. Methods: Serum tPSA, cPSA (with CLIA) and IGF-I (with IRMA) levels were determined in 41 patients with prostatic carcinoma, 60 patients with benign prosta- tic hypertrophy (BPH) and 55 controls. Results: The serum tPSA, cPSA and IGF-I levels in patients with prostatic cancer were significantly higher than those in patients with BPH and controls (P<0.01). Taking the cut-off values of 4ng/ml, 3.6ng/ml and 150 for tPSA, cPSA and IGF-I respectively, the combined determination of these three items would yield a sensitivity of 88.6%, specificity of 84.9%, positive predicative value of 83% and negative predicative value of 90.0% for diagnosis of prostatic cancer. Conclusion: Combined determination of tPSA, cPSA and IGF-I would yield better sensitive and accurate diagnostic rate in patients with prostatic cancer, especially in those with laboratory values within the 'grey zone'. (authors)

  15. The cAMP Response Element Binding protein (CREB) is activated by Insulin-like Growth Factor-1 (IGF-1) and regulates myostatin gene expression in skeletal myoblast

    International Nuclear Information System (INIS)

    Zuloaga, R.; Fuentes, E.N.; Molina, A.; Valdés, J.A.

    2013-01-01

    Highlights: •IGF-1 induces the activation of CREB via IGF-1R/PI3K/PLC signaling pathway. •Calcium dependent signaling pathways regulate myostatin gene expression. •IGF-1 regulates myostatin gene expression via CREB transcription in skeletal myoblast. -- Abstract: Myostatin, a member of the Transforming Growth Factor beta (TGF-β) superfamily, plays an important role as a negative regulator of skeletal muscle growth and differentiation. We have previously reported that IGF-1 induces a transient myostatin mRNA expression, through the activation of the Nuclear Factor of Activated T cells (NFAT) in an IP 3 /calcium-dependent manner. Here we examined the activation of CREB transcription factor as downstream targets of IGF-1 during myoblast differentiation and its role as a regulator of myostatin gene expression. In cultured skeletal myoblast, IGF-1 induced the phosphorylation and transcriptional activation of CREB via IGF-1 Receptor/Phosphatidylinositol 3-Kinase (PI3K)/Phospholipase C gamma (PLC γ), signaling pathways. Also, IGF-1 induced calcium-dependent molecules such as Calmodulin Kinase II (CaMK II), Extracellular signal-regulated Kinases (ERK), Protein Kinase C (PKC). Additionally, we examined myostatin mRNA levels and myostatin promoter activity in differentiated myoblasts stimulated with IGF-1. We found a significant increase in mRNA contents of myostatin and its reporter activity after treatment with IGF-1. The expression of myostatin in differentiated myoblast was downregulated by the transfection of siRNA–CREB and by pharmacological inhibitors of the signaling pathways involved in CREB activation. By using pharmacological and genetic approaches together these data demonstrate that IGF-1 regulates the myostatin gene expression via CREB transcription factor during muscle cell differentiation

  16. The cAMP Response Element Binding protein (CREB) is activated by Insulin-like Growth Factor-1 (IGF-1) and regulates myostatin gene expression in skeletal myoblast

    Energy Technology Data Exchange (ETDEWEB)

    Zuloaga, R. [Facultad de Ciencias Biológicas, Universidad Andres Bello, Santiago (Chile); Fuentes, E.N.; Molina, A. [Facultad de Ciencias Biológicas, Universidad Andres Bello, Santiago (Chile); Interdisciplinary Center for Aquaculture Research (INCAR), Víctor Lamas 1290, PO Box 160-C, Concepción (Chile); Valdés, J.A., E-mail: jvaldes@unab.cl [Facultad de Ciencias Biológicas, Universidad Andres Bello, Santiago (Chile); Interdisciplinary Center for Aquaculture Research (INCAR), Víctor Lamas 1290, PO Box 160-C, Concepción (Chile)

    2013-10-18

    Highlights: •IGF-1 induces the activation of CREB via IGF-1R/PI3K/PLC signaling pathway. •Calcium dependent signaling pathways regulate myostatin gene expression. •IGF-1 regulates myostatin gene expression via CREB transcription in skeletal myoblast. -- Abstract: Myostatin, a member of the Transforming Growth Factor beta (TGF-β) superfamily, plays an important role as a negative regulator of skeletal muscle growth and differentiation. We have previously reported that IGF-1 induces a transient myostatin mRNA expression, through the activation of the Nuclear Factor of Activated T cells (NFAT) in an IP{sub 3}/calcium-dependent manner. Here we examined the activation of CREB transcription factor as downstream targets of IGF-1 during myoblast differentiation and its role as a regulator of myostatin gene expression. In cultured skeletal myoblast, IGF-1 induced the phosphorylation and transcriptional activation of CREB via IGF-1 Receptor/Phosphatidylinositol 3-Kinase (PI3K)/Phospholipase C gamma (PLC γ), signaling pathways. Also, IGF-1 induced calcium-dependent molecules such as Calmodulin Kinase II (CaMK II), Extracellular signal-regulated Kinases (ERK), Protein Kinase C (PKC). Additionally, we examined myostatin mRNA levels and myostatin promoter activity in differentiated myoblasts stimulated with IGF-1. We found a significant increase in mRNA contents of myostatin and its reporter activity after treatment with IGF-1. The expression of myostatin in differentiated myoblast was downregulated by the transfection of siRNA–CREB and by pharmacological inhibitors of the signaling pathways involved in CREB activation. By using pharmacological and genetic approaches together these data demonstrate that IGF-1 regulates the myostatin gene expression via CREB transcription factor during muscle cell differentiation.

  17. Fetal programming of insulin-like growth factor (IGF)-I and IGF-binding protein-3: evidence for an altered response to undernutrition in late gestation following exposure to periconceptual undernutrition in the sheep.

    Science.gov (United States)

    Gallaher, B W; Breier, B H; Keven, C L; Harding, J E; Gluckman, P D

    1998-12-01

    It has been demonstrated in several animal models that undernutrition in utero has significant long lasting effects on subsequent fetal and postnatal development. To address the hypothesis that the insulin-like growth factors (IGFs) may mediate such effects, our study examined whether a period of periconceptual maternal undernutrition could have a lasting influence on the IGF axis in the fetal sheep. Ewes were either allowed to feed ad libitum or kept undernourished from day 60 prior to mating until day 30 after conception, and then both groups were allowed to feed ad libitum. These groups were further divided at day 105 of gestation, either being fed ad libitum or undernourished until day 115 of gestation. Fetal and maternal blood samples were obtained at both day 105 and 115 of gestation. We describe the development of a specific homologous RIA to measure ovine IGF-binding protein-3 (IGFBP-3) in fetal and maternal sheep plasma. Fetal plasma IGFBP-3 and IGF-I concentrations were significantly (Pfetal plasma IGFBP-2 levels were unchanged. The degree of reduction in fetal plasma IGFBP-3 and IGF-I between day 105 and 115 of gestation as a response to acute maternal undernutrition was significantly greater (Pfetal plasma IGFBP-3 concentrations were not the result of increased proteolytic activity. These results suggest that exposure to maternal periconceptual undernutrition reprograms IGFBP-3 and IGF-I regulation in the developing sheep fetus, altering its response to undernutrition in late gestation.

  18. Characterization and validation of new tools for measuring site-specific cardiac troponin I phosphorylation.

    Science.gov (United States)

    Thoemmes, Stephen F; Stutzke, Crystal A; Du, Yanmei; Browning, Michael D; Buttrick, Peter M; Walker, Lori A

    2014-01-31

    Phosphorylation of cardiac troponin I is a well established mechanism by which cardiac contractility is modulated. However, there are a number of phosphorylation sites on TnI which contribute singly or in combination to influence cardiac function. Accordingly, methods for accurately measuring site-specific TnI phosphorylation are needed. Currently, two strategies are employed: mass spectrometry, which is costly, difficult and has a low throughput; and Western blotting using phospho-specific antibodies, which is limited by the availability of reagents. In this report, we describe a cohort of new site-specific TnI phosphoantibodies, generated against physiologically relevant phosphorylation sites, that are superior to the current commercially available antibodies: to phospho-serine 22/23 which shows a >5-fold phospho-specificity for phosphorylated TnI; to phospho-serine 43, which has >3-fold phospho-specificity for phosphorylated TnI; and phospho-serine 150 which has >2-fold phospho-specificity for phosphorylated TnI. These new antibodies demonstrated greater sensitivity and specificity for the phosphorylated TnI than the most widely used commercially available reagents. For example, at a protein load of 20 μg of total cardiac extract, a commercially available antibody recognized both phosphorylated and dephosphorylated TnI to the same degree. At the same protein load our phospho-serine 22/23 antibody exhibited no cross-reactivity with dephosphorylated TnI. These new tools should allow a more accurate assessment and a better understanding of the role of TnI phosphorylation in the response of the heart to pathologic stress. Copyright © 2013 Elsevier B.V. All rights reserved.

  19. Identification of binding sites for an insulin-like growth factor (IGF-I) in the median eminence of the rat brain by quantitative autoradiography

    International Nuclear Information System (INIS)

    Bohannon, N.J.; Figlewicz, D.P.; Corp, E.S.; Wilcox, B.J.; Porte, D. Jr.; Baskin, D.G.

    1986-01-01

    The microanatomical location of IGF-I binding in the rat brain was determined by in vitro autoradiography with slide-mounted sections of frozen brain. Sections incubated in 0.1 nM [ 125 I]-iodo-IGF-I produced a dense grain concentration in regions of the autoradiographic image corresponding to the external palisade zone of the median eminence; other hypothalamic regions were not so heavily labeled. This reaction was significantly reduced in the presence of 100 nM IGF-I. Measurement of binding by computer digital image analysis of autoradiographic images showed that specific binding for IGF-I in the median eminence was 41.3 +/- 8 X 10(-3) fmol/mm2 (mean +/- SEM); nonspecific binding was 11.9 +/- 1.8 X 10(-3) fmol/mm2. In contrast, specific binding to other hypothalamic regions was uniformly lower. In a separate experiment, 1000 nM unlabeled insulin was added. Without insulin, specific binding was 23 +/- 0.9 X 10(-3) fmol/mm2; nonspecific binding was 8 +/- 0.5 X 10(-3) fmol/mm2. In the presence of 1000 nM unlabeled insulin, specific binding for [ 125 I]-iodo-IGF-I was 23 +/- 1 X 10(-3) fmol/mm2. The results suggest that a high concentration of receptors for an IGF-I-like molecule is present in the median eminence

  20. The transmembrane domain of the p75 neurotrophin receptor stimulates phosphorylation of the TrkB tyrosine kinase receptor.

    Science.gov (United States)

    Saadipour, Khalil; MacLean, Michael; Pirkle, Sean; Ali, Solav; Lopez-Redondo, Maria-Luisa; Stokes, David L; Chao, Moses V

    2017-10-06

    The function of protein products generated from intramembraneous cleavage by the γ-secretase complex is not well defined. The γ-secretase complex is responsible for the cleavage of several transmembrane proteins, most notably the amyloid precursor protein that results in Aβ, a transmembrane (TM) peptide. Another protein that undergoes very similar γ-secretase cleavage is the p75 neurotrophin receptor. However, the fate of the cleaved p75 TM domain is unknown. p75 neurotrophin receptor is highly expressed during early neuronal development and regulates survival and process formation of neurons. Here, we report that the p75 TM can stimulate the phosphorylation of TrkB (tyrosine kinase receptor B). In vitro phosphorylation experiments indicated that a peptide representing p75 TM increases TrkB phosphorylation in a dose- and time-dependent manner. Moreover, mutagenesis analyses revealed that a valine residue at position 264 in the rat p75 neurotrophin receptor is necessary for the ability of p75 TM to induce TrkB phosphorylation. Because this residue is just before the γ-secretase cleavage site, we then investigated whether the p75(αγ) peptide, which is a product of both α- and γ-cleavage events, could also induce TrkB phosphorylation. Experiments using TM domains from other receptors, EGFR and FGFR1, failed to stimulate TrkB phosphorylation. Co-immunoprecipitation and biochemical fractionation data suggested that p75 TM stimulates TrkB phosphorylation at the cell membrane. Altogether, our results suggest that TrkB activation by p75(αγ) peptide may be enhanced in situations where the levels of the p75 receptor are increased, such as during brain injury, Alzheimer's disease, and epilepsy. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  1. CLINICAL AND HORMONAL MILIEU OF 9 PATIENTS WITH PRIMARY GROWTH HORMONE INSENSITIVITY SYNDROME AND THEIR RESPONSE TO IGF-I GENERATION TEST

    Directory of Open Access Journals (Sweden)

    M. Razzaghy-Azar

    2006-05-01

    Full Text Available Primary growth hormone insensitivity syndrome (GHIS is a rare entity which can be due to defects in growth hormone (GH receptor that is called type 1 Laron syndrome (T1LS or post receptor defects (type 2 Laron syndrome . The aim of study was determining the clinical and hormonal milieu of the patients with primary GHIS and their response to IGF-I (insulin like growth factor-I generation test (IGT. GH, IGF-I, IGF-II, IGF binding protein 1 and 3 (BP-1 and BP-3, GH binding protein (GHBP and anti-GH antibody were detected by ELISA and RIA methods. IGF-I and BP-3 were measured before and after IGT. Nine patients (8 males, 1 female (mean age ± SD, 6.4 ± 5 years with severe short stature and high GH level were studied. Height SDS was - 8.5 ± 2.6. In 7 patients GHBP was zero, IGF-I and BP-3 were low and did not increase after IGT, so they had T1LS. Two brothers did not show the hormonal milieu of GH receptor defect, and were called non Laron syndrome (NLS. Birth weight in patients with T1LS and NLS was 3.65 ± 0.2 Kg and 1.65 ± 0.2 Kg, respectively (P = 0.001. All of the patients had typical clinical feature of GH-deficiency, but nasal bridge depression and microphallus were not seen in NLS. GH treatment of NLS, normalized their growth velocity, but without catch up growth. In conclusion IGT can differentiate Laron syndrome from other types of short stature. GH and IGF-I of fetus have no role in intrauterine growth.

  2. Postpartum IGF-I and IGFBP-2 levels are prospectively associated with the development of type 2 diabetes in women with previous gestational diabetes mellitus.

    Science.gov (United States)

    Lappas, M; Jinks, D; Shub, A; Willcox, J C; Georgiou, H M; Permezel, M

    2016-12-01

    Women with previous gestational diabetes mellitus (GDM) are at greater risk of developing type 2 diabetes. In the general population, the insulin-like growth factor (IGF) system has been implicated in the development of type 2 diabetes. The aim of this study was to determine if circulating IGF-I, IGF-II, IGFBP-1 and IGFBP-2 levels 12weeks following a GDM pregnancy are associated with an increased risk of developing type 2 diabetes. IGF-I, IGF-II, IGFBP-1 and IGFBP-2 levels were measured in 98 normal glucose tolerant women, 12weeks following an index GDM pregnancy using enzyme immunoassay. Women were assessed for up to 10years for the development of overt type 2 diabetes. Among the 98 women with previous GDM, 21 (21%) developed diabetes during the median follow-up period of 8.5years. After adjusting for age and BMI, IGF-I and IGFBP-2 were significantly associated with the development of type 2 diabetes. In a clinical model of prediction of type 2 diabetes that included age, BMI, pregnancy fasting glucose and postnatal fasting glucose, the addition of IGF-I and IGFBP-2 resulted in an improvement in the net reclassification index of 17.8%. High postpartum IGF-I and low postpartum IGFBP-2 levels are a significant risk factor for the development of type 2 diabetes in women with a previous history of GDM. This is the first report that identifies IGF-I and IGFBP-2 as a potential biomarker for the prediction of type 2 diabetes in women with a history of GDM. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  3. Efficient and sustained IGF-1 expression in the adipose tissue-derived stem cells mediated via a lentiviral vector.

    Science.gov (United States)

    Chen, Ting; Huang, Dangsheng; Chen, Guanghui; Yang, Tingshu; Yi, Jun; Tian, Miao

    2015-02-01

    The adipose tissue-derived stem cells (ADSCs) represent a significant area of the cell therapy. Genetic modification of ADSCs may further improve their therapeutic potential. Here, we aimed to generate a lentiviral vector expressing insulin-like growth factor-I (IGF-1) and investigate the impact of IGF-1 transduction on the properties of cultured ADSCs. Isolated rat ADSCs were assessed by flow cytometric analysis. IGF-1 was cloned and inserted into the pLenO-DCE plasmid to acquire pLenO-DCE-IGF-1 plasmid. Lentivirus was enveloped with pRsv-REV, pMDlg-pRRE and pMD2G plasmids in 293T cells. The ADSCs were transfected with the vectors. And then IGF-1-induced anti-apoptosis was evaluated by annexin V-FITC. Besides, proliferation of cells was detected by MTT assay and EdU. Moreover, Akt phosphorylation was evaluated by Western blotting analysis. Stable expression of IGF-1 in ADSCs was confirmed. ADSCs were positive for CD90 and CD29, but negative for CD31, CD34 and CD45. The transduction of IGF-1 to the ADSCs caused a dramatic increase in P-Akt expression. Over-expression of IGF-1 in ADSCs could improve the paracine of IGF-1 in a time-dependent manner, but could not promote the proliferation of ADSCs. This study indicated that lentiviral vectors offered a promising mean of delivering IGF-1 to the ADSCs. Lentiviral-mediated over-expression of therapeutic IGF-1 gene in ADSCs could prolong the anti-apoptosis effect of IGF-1, which might be induced by the activation of the PI3K/Akt pathway. And our data would improve the efficacy of ADSC-based therapies.

  4. Differential effects of vasopressin and phenylephrine on protein kinase C-mediated protein phosphorylations in isolated hepatocytes

    International Nuclear Information System (INIS)

    Cooper, R.H.; Johanson, R.A.; Wiliamson, J.R.

    1986-01-01

    Receptor-mediated breakdown of inositol lipids produces two intracellular signals, diacylglycerol, which activates protein kinase C, and inositol trisphosphate, which causes release of intracellular vesicular Ca 2+ . This study examined the effects of Ca 2+ -ionophores, vasopressin, phenylephrine, and phorbol ester (PMA) on hepatocyte protein phosphorylations. [ 32 P] Phosphoproteins from hepatocytes prelabeled with 32 P were resolved by 2-dimensional SDS-PAGE and corresponding autoradiographs were quantitated by densitometric analysis. The phosphorylation of five proteins, a plasma membrane bound 16 kDa protein with pI 6.4, a cytosolic 16 kDa protein with pI 5.8, and proteins with Mr's of 36 kDa, 52 kDa, and 68 kDa, could be attributed to phosphorylation by protein kinase C since the phosphorylation was stimulated by PMA. When the vasopressin concentration was varied, low vasopressin stimulated the phosphorylation of only the membrane bound 16 kDa protein of the above set of proteins, while higher vasopressin concentrations were required to stimulate the phosphorylation of all five proteins. Phenylephrine, even at supramaximal concentrations, stimulated the phosphorylation of only the membrane bound 16 kDa protein. These results suggest that phenylephrine is a less potent activator of protein kinase C than vasopressin by virtue of limited or localized diacylglycerol production

  5. Interleukin-6 stimulates Akt and p38 MAPK phosphorylation and fibroblast migration in non-diabetic but not diabetic mice.

    Directory of Open Access Journals (Sweden)

    Tsubame Nishikai-Yan Shen

    Full Text Available Persistent inflammatory environment and abnormal macrophage activation are characteristics of chronic diabetic wounds. Here, we attempted to characterize the differences in macrophage activation and temporal variations in cytokine expression in diabetic and non-diabetic wounds, with a focus on interleukin (IL-6 mRNA expression and the p38 MAPK and PI3K/Akt signaling pathways. Cutaneous wound closure, CD68- and arginase-1 (Arg-1-expressing macrophages, and cytokine mRNA expression were examined in non-diabetic and streptozotocin-induced type 1 diabetic mice at different time points after injury. The effect of IL-6 on p38 MAPK and Akt phosphorylation was investigated, and an in vitro scratch assay was performed to determine the role of IL-6 in primary skin fibroblast migration. Before injury, mRNA expression levels of the inflammatory markers iNOS, IL-6, and TNF-α were higher in diabetic mice; however, IL-6 expression was significantly lower 6 h post injury in diabetic wounds than that in non-diabetic wounds. Non-diabetic wounds exhibited increased p38 MAPK and Akt phosphorylation; however, no such increase was found in diabetic wounds. In fibroblasts from non-diabetic mice, IL-6 increased the phosphorylation of p38 MAPK and levels of its downstream factor CREB, and also significantly increased Akt phosphorylation and levels of its upstream factor P13K. These effects of IL-6 were not detected in fibroblasts derived from the diabetic mice. In scratch assays, IL-6 stimulated the migration of primary cultured skin fibroblasts from the non-diabetic mice, and the inhibition of p38 MAPK was found to markedly suppress IL-6-stimulated fibroblast migration. These findings underscore the critical differences between diabetic and non-diabetic wounds in terms of macrophage activation, cytokine mRNA expression profile, and involvement of the IL-6-stimulated p38 MAPK-Akt signaling pathway. Aberrant macrophage activation and abnormalities in the cytokine m

  6. Changes in calcitropic hormones, bone markers and insulin-like growth factor I (IGF-I) during pregnancy and postpartum: a controlled cohort study.

    Science.gov (United States)

    Møller, U K; Streym, S; Mosekilde, L; Heickendorff, L; Flyvbjerg, A; Frystyk, J; Jensen, L T; Rejnmark, L

    2013-04-01

    Pregnancy and lactation cause major changes in calcium homeostasis and bone metabolism. This population-based cohort study presents the physiological changes in biochemical indices of calcium homeostasis and bone metabolism during pregnancy and lactation We describe physiological changes in calcium homeostasis, calcitropic hormones and bone metabolism during pregnancy and lactation. We studied 153 women planning pregnancy (n=92 conceived) and 52 non-pregnant, age-matched female controls. Samples were collected prior to pregnancy, once each trimester and 2, 16 and 36 weeks postpartum. The controls were followed in parallel. P-estradiol (E2), prolactin and 1,25-dihydroxyvitamin D (1,25(OH)2D) increased (phormone (P-PTH) and calcitonin decreased (pgrowth factor I (IGF-I) was suppressed (pbone resorption and formation rose and fall, respectively (pbone formation markers increased in association with IGF-I changes (pbone turnover markers were associated with lactation status (pbone markers indicated a negative bone balance. The rise in bone formation in late pregnancy may be initiated by a spike in IGF-I levels. The high bone turnover in lactating women may be related to high prolactin and PTH levels, low E2 levels and perhaps increased parathyroid hormone-related protein levels.

  7. The immune-endocrine loop during aging: role of growth hormone and insulin-like growth factor-I.

    Science.gov (United States)

    Burgess, W; Liu, Q; Zhou, J; Tang, Q; Ozawa, A; VanHoy, R; Arkins, S; Dantzer, R; Kelley, K W

    1999-01-01

    Why a primary lymphoid organ such as the thymus involutes during aging remains a fundamental question in immunology. Aging is associated with a decrease in plasma growth hormone (somatotropin) and IGF-I, and this somatopause of aging suggests a connection between the neuroendocrine and immune systems. Several investigators have demonstrated that treatment with either growth hormone or IGF-I restores architecture of the involuted thymus gland by reversing the loss of immature cortical thymocytes and preventing the decline in thymulin synthesis that occurs in old or GH-deficient animals and humans. The proliferation, differentiation and functions of other components of the immune system, including T and B cells, macrophages and neutrophils, also demonstrate age-associated decrements that can be restored by IGF-I. Knowledge of the mechanism by which cytokines and hormones influence hematopoietic cells is critical to improving the health of aged individuals. Our laboratory has recently demonstrated that IGF-I prevents apoptosis in promyeloid cells, which subsequently permits these cells to differentiate into neutrophils. We also demonstrated that IL-4 acts much like IGF-I to promote survival of promyeloid cells and to activate the enzyme phosphatidylinositol 3'-kinase (PI 3-kinase). However, the receptors for IGF-I and IL-4 are completely different, with the intracellular beta chains of the IGF receptor possessing intrinsic tyrosine kinase activity and the alpha and gammac subunit of the heterodimeric IL-4 receptor utilizing the Janus kinase family of nonreceptor protein kinases to tyrosine phosphorylate downstream targets. Both receptors share many of the components of the PI 3-kinase signal transduction pathway, converging at the level of insulin receptor substrate-1 or insulin receptor subtrate-2 (formally known as 4PS, or IL-4 Phosphorylated Substrate). Our investigations with IGF-I and IL-4 suggest that PI 3-kinase inhibits apoptosis by maintaining high levels of

  8. IGF-IR targeted therapy: Past, present and future

    NARCIS (Netherlands)

    J.A.M.J.L. Janssen (Joseph); A.J. Varewijck (Aimee)

    2014-01-01

    textabstractThe IGF-I receptor (IGF-IR) has been studied as an anti-cancer target. However, monotherapy trials with IGF-IR targeted antibodies or with IGF-IR specific tyrosine kinase inhibitors have, overall, been very disappointing in the clinical setting. This review discusses potential reasons

  9. Mecasermin rinfabate: insulin-like growth factor-I/insulin-like growth factor binding protein-3, mecaserimin rinfibate, rhIGF-I/rhIGFBP-3.

    Science.gov (United States)

    2005-01-01

    Insmed is developing mecasermin rinfabate, a recombinant complex of insulin-like growth factor-I (rhIGF-I) and binding protein-3 (rhIGFBP-3) [insulin-like growth factor-I/insulin-like growth factor binding protein-3, rhIGF-I/rhIGFBP-3, SomatoKine], for a number of metabolic and endocrine indications. In the human body, IGF-I circulates in the blood bound to a binding protein-3 (IGFBP-3), which regulates the delivery of IGF-I to target tissues, and particular proteases clip them apart in response to stresses and release IGF-I as needed. IGF-I, a naturally occurring hormone, is necessary for normal growth and metabolism. For the treatment of IGF-I deficiency, it is desirable to administer IGF-I bound to IGFBP-3 to maintain the normal equilibrium of these proteins in the blood. Mecasermin rinfabate (rhIGF-I/rhIGFBP-3) mimics the effects of the natural protein complex in the bloodstream and would augment the natural supply of these linked compounds. The most advanced indication in development of mecasermin rinfabate is the treatment of severe growth disorders due to growth hormone insensitivity syndrome (GHIS), also called Laron syndrome. GHIS is a genetic condition in which patients do not produce adequate quantities of IGF because of a failure to respond to the growth hormone signal. This results in a slower growth rate and short stature. Mecasermin rinfabate also has potential as replacement therapy for IGF-I, which may become depleted in indications such as major surgery, organ damage/failure, traumatic injury, cachexia and severe burn trauma. It also has potential for the treatment of osteoporosis. Mecasermin rinfabate was developed by Celtrix using its proprietary recombinant protein production technology. Subsequently, Celtrix was acquired by Insmed Pharmaceuticals on 1 June 2000. Insmed and Avecia of the UK have signed an agreement for manufacturing mecasermin rinfabate and its components, rhIGF-1 and rhIGFBP-3. CGMP clinical production of mecasermin rinfabate

  10. The effect of insulin-like growth factor I on proteoglycan metabolism in immature and adult bovine articular cartilage

    International Nuclear Information System (INIS)

    Barone-Varelas, J.

    1989-01-01

    Explants of articular cartilage from calf (15 weeks old) and steer (18-24 months old) were cultured for up to 19 days in medium containing either insulin-like growth factor (IGF-I) or 20% fetal bovine serum (FBS). Explants cultured in medium alone were controls. 35 S-proteoglycans (PGs) synthesized on day 7 of culture during a 5-hour pulse with 35 S-sulfate were isolated, quantified and characterized. Lower concentrations of IGF-I were required for maximal stimulation of PG synthesis in calf than in steer (10 vs 20 ng/ml). In calf, IGF-I was as effective as 20% FABS in stimulating PG synthesis. In steer, PG synthesis in the presence of IGF-I reached its maximum at a rate that was half that obtained with 20% FBS. The stimulation by IGF-I or FBS was not accompanied at either age by alterations in the size and composition of the aggregating PGs nor by changes in the relative proportions of the CS-rich and CS-poor PG subpopulations. Importantly, the newly synthesized calf and steer PGs retained marked age-related differences in composition regardless of the culture conditions. The effects of exogenously added IGF-I and FBS on the rate of turnover of cartilage PGs was also studied. In calf, IGF-I and FBS did not significantly alter the rate of turnover of either the 35 S-PGs synthesized in vitro or of the unlabeled PGs representing mostly molecules synthesize and organized into the matrix in vivo. In steer, explants cultured in the absence of IGF-I or FBS exhibited very fast rates of turnover which resulted in severe depletion of matrix PG with time. Importantly, IGF-I and FBS were equally effective in reducing the turnover rate of 35 S-PGs and unlabeled PGs and in preventing PG depletion. These results demonstrate age-related differences in the effect of IGF-I on PG synthesis by articular chondrocytes

  11. IGF-1 induces SOCS-2 but not SOCS-1 and SOCS-3 transcription in juvenile Nile tilapia (Oreochromis niloticus).

    Science.gov (United States)

    Liu, Cai-Zhi; Luo, Yuan; Limbu, Samwel Mchele; Chen, Li-Qiao; Du, Zhen-Yu

    2018-05-20

    Insulin-like growth factor-1 (IGF-1) plays a crucial role in regulating growth in vertebrates whereas suppressors of cytokine signaling (SOCS) act as feedback inhibitors of the GH/IGF-1 axis. Although SOCS-2 binds the IGF-1 receptor and inhibits IGF-1-induced STAT3 activation, presently there is no clear evidence as to whether IGF-1 could induce SOCS gene expression. The current study aimed to determine whether IGF-1 could induce the transcription of SOCS in juvenile Nile tilapia ( Oreochromis niloticus ). We show that there is a common positive relationship between the mRNA expression of IGF-I and SOCS-2 under different nutritional statuses and stimulants, but not the mRNA expression of SOCS-1 and SOCS-3 Furthermore, rhIGF-1 treatment and transcriptional activity assay confirmed the hypothesis that IGF-1 could induce SOCS-2 expression, whereas it had no effect or even decreased the expression of SOCS-1 and SOCS-3 Overall, we obtained evidence that the transcription of SOCS-2, but not SOCS-1 or SOCS-3, could be induced by IGF signaling, suggesting that SOCS-2 serves as a feedback suppressor of the IGF-1 axis in juvenile Nile tilapia. © 2018. Published by The Company of Biologists Ltd.

  12. Matrix metalloproteinase-1 facilitates MSC migration via cleavage of IGF-2/IGFBP2 complex.

    Science.gov (United States)

    Guan, Shou P; Lam, Alan T L; Newman, Jennifer P; Chua, Kevin L M; Kok, Catherine Y L; Chong, Siao T; Chua, Melvin L K; Lam, Paula Y P

    2018-01-01

    The specific mechanism underlying the tumor tropism of human mesenchymal stem cells (MSCs) for cancer is not well defined. We previously showed that the migration potential of MSCs correlated with the expression and protease activity of matrix metalloproteinase (MMP)-1. Furthermore, highly tumor-tropic MSCs expressed higher levels of MMP-1 and insulin-like growth factor (IGF)-2 than poorly migrating MSCs. In this study, we examined the functional roles of IGF-2 and MMP-1 in mediating the tumor tropism of MSCs. Exogenous addition of either recombinant IGF-2 or MMP-1 could stimulate MSC migration. The correlation between IGF-2, MMP-1 expression, and MSC migration suggests that MMP-1 may play a role in regulating MSC migration via the IGF-2 signaling cascade. High concentrations of IGF binding proteins (IGFBPs) can inhibit IGF-stimulated functions by blocking its binding to its receptors and proteolysis of IGFBP is an important mechanism for the regulation of IGF signaling. We thus hypothesized that MMP-1 acts as an IGFBP2 proteinase, resulting in the cleavage of IGF-2/IGFBP2 complex and extracellular release of free IGF-2. Indeed, our results showed that conditioned media from highly migrating MSCs, which expressed high levels of MMP-1, cleaved the IGF-2/IGFBP2 complex. Taken together, these results showed that the MMP-1 secreted by highly tumor-tropic MSCs cleaved IGF-2/IGFBP2 complex. Free IGF-2 released from the complex may facilitate MSC migration toward tumor.

  13. Insulin and IGF-1 improve mitochondrial function in a PI-3K/Akt-dependent manner and reduce mitochondrial generation of reactive oxygen species in Huntington's disease knock-in striatal cells.

    Science.gov (United States)

    Ribeiro, Márcio; Rosenstock, Tatiana R; Oliveira, Ana M; Oliveira, Catarina R; Rego, A Cristina

    2014-09-01

    Oxidative stress and mitochondrial dysfunction have been described in Huntington's disease, a disorder caused by expression of mutant huntingtin (mHtt). IGF-1 was previously shown to protect HD cells, whereas insulin prevented neuronal oxidative stress. In this work we analyzed the role of insulin and IGF-1 in striatal cells derived from HD knock-in mice on mitochondrial production of reactive oxygen species (ROS) and related antioxidant and signaling pathways influencing mitochondrial function. Insulin and IGF-1 decreased mitochondrial ROS induced by mHtt and normalized mitochondrial SOD activity, without affecting intracellular glutathione levels. IGF-1 and insulin promoted Akt phosphorylation without changing the nuclear levels of phosphorylated Nrf2 or Nrf2/ARE activity. Insulin and IGF-1 treatment also decreased mitochondrial Drp1 phosphorylation, suggesting reduced mitochondrial fragmentation, and ameliorated mitochondrial function in HD cells in a PI-3K/Akt-dependent manner. This was accompanied by increased total and phosphorylated Akt, Tfam, and mitochondrial-encoded cytochrome c oxidase II, as well as Tom20 and Tom40 in mitochondria of insulin- and IGF-1-treated mutant striatal cells. Concomitantly, insulin/IGF-1-treated mutant cells showed reduced apoptotic features. Hence, insulin and IGF-1 improve mitochondrial function and reduce mitochondrial ROS caused by mHtt by activating the PI-3K/Akt signaling pathway, in a process independent of Nrf2 transcriptional activity, but involving enhanced mitochondrial levels of Akt and mitochondrial-encoded complex IV subunit. Copyright © 2014 Elsevier Inc. All rights reserved.

  14. Evidence for requirement of tyrosine phosphorylation in endothelial P2Y- and P2U- purinoceptor stimulation of prostacyclin release.

    Science.gov (United States)

    Bowden, A.; Patel, V.; Brown, C.; Boarder, M. R.

    1995-01-01

    1. The release of prostacyclin (PGI2) from vascular endothelial cells is stimulated by ATP acting at G protein-coupled P2-purinoceptors. Here we investigate the hypothesis that tyrosine protein phosphorylations are involved in this response. 2. The use of Western blots with anti-phosphotyrosine antibodies showed that 30 microM 2MeSATP (selective for P2Y-purinoceptors), 300 microM UTP (selective for P2U-purinoceptors) and 300 microM ATP (effective at both these purinoceptors), each stimulate the tyrosine phosphorylation of proteins in bovine cultured aortic endothelial cells. Each of these agonists also stimulates 6-keto PGF1 alpha accumulation in the medium (an index of PGI2 release) in these cells in the same period. 3. The tyrosine kinase inhibitor, genistein, inhibits the 6-keto PGF1 alpha response with the same concentration-dependency (1-100 microM) as the tyrosine phosphorylation response. 4. Tyrphostin, a structurally and functionally distinct tyrosine kinase inhibitor, is also a potent inhibitor (0.1-10 microM) of the 6-keto PGF1 alpha response. 5. Neither tyrphostin nor genistein inhibit the phospholipase C response to P2-purinoceptor stimulation. Furthermore, these inhibitors do not affect the 6-keto PGF1 alpha response to ionomycin. 6. These results show that the regulation of vascular endothelial cells by ATP acting at both P2Y- and P2U-purinoceptors involves the stimulation of tyrosine phosphorylation, and suggest that this is a necessary event for the purinoceptor-mediated stimulation of PGI2 production. Images Figure 1 Figure 5 PMID:8590971

  15. The association between insulin-like growth factor 1 (IGF-1), IGF-binding proteins (IGFBPs), and the carboxyterminal propeptide of type I procollagen (PICP) in pre- and postmenopausal women with rheumatoid arthritis.

    Science.gov (United States)

    Szeremeta, A; Jura-Półtorak, A; Komosińska-Vassev, K; Zoń-Giebel, A; Kapołka, D; Olczyk, K

    2017-05-01

    To assess the association between plasma levels of the insulin-like growth factor (IGF) system including IGF-1, IGF-binding proteins (IGFBPs) including IGFBP-1, total (t-)IGFBP-3 and functional (f-)IGFBP-3, and the carboxyterminal propeptide of type I procollagen (PICP) in pre- and postmenopausal women with rheumatoid arthritis (RA). Plasma concentrations of IGF-1, IGFBP-1, t-IGFBP-3, f-IGFBP-3, and PICP were measured by immunoassay. No significant difference was observed in plasma IGF-1 levels between pre- and postmenopausal subjects. Plasma levels of IGFBP-1 were elevated in RA. PICP and f-IGFBP-3 were greatly affected by menopausal status. Of the three IGFBPs tested, only f-IGFBP-3 plasma levels in RA women correlated negatively with age and disease duration. A positive correlation was demonstrated between PICP and erythrocyte sedimentation rate (ESR) in RA. Moreover, there was no correlation between PICP and IGF-1 and any of the IGFBPs in RA women. Considerable disruption of the IGF system in RA was found to be related to disease activity and duration. Changes in the IGF-IGFBP axis and PICP levels were different in pre- and postmenopausal women with RA. Elevated plasma PICP concentrations may indicate an increased rate of bone formation in postmenopausal RA women. Additionally, the observed changes in the IGF/IGFBP system did not affect bone formation during RA.

  16. EXPRESSION OF GROWTH HORMONE (PhGH GENE AND ANALYSIS OF INSULINE-LIKE GROWTH FACTOR I (IGF-I PRODUCTION IN AFRICAN CATFISH (Clarias gariepinus TRANSGENIC F-1

    Directory of Open Access Journals (Sweden)

    Huria Marnis

    2013-12-01

    Full Text Available We have previously produced F-1 transgenic of African catfish from crosses between founder transgenic female and non transgenic male. The aim of this study was to evaluate distribution and expression PhGH growth hormone gene transgenic African catfish organs and to measure the concentration of IGF-I in plasma. Transgene was detected using the PCR method in various organs, namely pituitary, brain, liver, heart, spleen, kidney, intestine, stomach, muscle, gill, and eye. Transgene expression levels were analyzed using the method of quantitative Reverse Transcriptase-Polymerase Chain Reaction (qRT-PCR. Plasma samples were analyzed for Insuline-like Growth Factor (IGF-I using Enzyme Linked Immunosorbent Assay (ELISA method. The results showed that the PhGH was detected and expressed in all organs of the transgenic African catfish (F-1. Liver exhibited the highest level of PhGH mRNA (23 x 106 copies. The plasma IGF-I levels in transgenic individuals were not significant than non transgenic. The higher level of exogenous PhGH gene expression may not represent the production of IGF-1.

  17. Plasma and tissue insulin-like growth factor-I receptor (IGF-IR) as a prognostic marker for prostate cancer and anti-IGF-IR agents as novel therapeutic strategy for refractory cases: a review.

    Science.gov (United States)

    Ozkan, Emine Elif

    2011-09-15

    Cancer database analysis indicates that prostate cancer is one of the most seen cancers in men meanwhile composing the leading cause of morbidity and mortality among developed countries. Current available therapies are surgery, radiotherapy and androgene ablation for prostate carcinoma. The response rate is as high nearly 90% however, most of these recur or become refractory and androgene independent (AI). Therefore recent studies intensified on molecular factors playing role on development of prostate carcinoma and novel treatment strategies targetting these factors and their receptors. Insulin-like growth factor-I (IGF-I) and its primary receptor insulin-like growth factor receptor-I (IGF-IR) are among these factors. Biologic functions and role in malign progression are primarily achieved via IGF-IR which is a type 2 tyrosine kinase receptor. IGF-IR plays an important role in mitogenesis, angiogenesis, transformation, apoptosis and cell motility. It also generates intensive proliferative signals leading to carcinogenesis in prostate tissue. So IGF-IR and its associated signalling system have provoked considerable interest over recent years as a novel therapeutic target in cancer. In this paper it is aimed to sum up the lately published literature searching the relation of IGF-IR and prostate cancer in terms of incidence, pathologic features, and prognosis. This is followed by a discussion of the different possible targets within the IGF-1R system, and drugs developed to interact at each target. A systems-based approach is then used to review the in vitro and in vivo data in the published literature of the following compounds targeting IGF-1R components using specific examples: growth hormone releasing hormone antagonists (e.g. JV-1-38), growth hormone receptor antagonists (e.g. pegvisomant), IGF-1R antibodies (e.g. CP-751,871, AVE1642/EM164, IMC-A12, SCH-717454, BIIB022, AMG 479, MK-0646/h7C10), and IGF-1R tyrosine kinase inhibitors (e.g. BMS-536942, BMS-554417

  18. Glucagon Decreases IGF-1 Bioactivity in Humans, Independently of Insulin, by Modulating Its Binding Proteins.

    Science.gov (United States)

    Sarem, Zeinab; Bumke-Vogt, Christiane; Mahmoud, Ayman M; Assefa, Biruhalem; Weickert, Martin O; Adamidou, Aikatarini; Bähr, Volker; Frystyk, Jan; Möhlig, Matthias; Spranger, Joachim; Lieske, Stefanie; Birkenfeld, Andreas L; Pfeiffer, Andreas F H; Arafat, Ayman M

    2017-09-01

    Depending on its lipolytic activity, glucagon plays a promising role in obesity treatment. Glucagon-induced growth hormone (GH) release can promote its effect on lipid metabolism, although the underlying mechanisms have not been well-defined. The present study highlights the glucagon effect on the GH/insulinlike growth factor 1 (IGF-1)/IGF-binding protein (IGFBP) axis in vivo and in vitro, taking into consideration insulin as a confounding factor. In a double-blind, placebo-controlled study, we investigated changes in GH, IGFBP, and IGF-1 bioactivity after intramuscular glucagon administration in 13 lean controls, 11 obese participants, and 13 patients with type 1 diabetes mellitus (T1DM). The effect of glucagon on the transcription factor forkhead box protein O1 (FOXO1) translocation, the transcription of GH/IGF-1 system members, and phosphorylation of protein kinase B (Akt) was further investigated in vitro. Despite unchanged total IGF-1 and IGFBP-3 levels, glucagon decreased IGF-1 bioactivity in all study groups by increasing IGFBP-1 and IGFBP-2. The reduction in IGF-1 bioactivity occurred before the glucagon-induced surge in GH. In contrast to the transient increase in circulating insulin in obese and lean participants, no change was observed in those with T1DM. In vitro, glucagon dose dependently induced a substantial nuclear translocation of FOXO1 in human osteosarcoma cells and tended to increase IGFBP-1 and IGFBP-2 gene expression in mouse primary hepatocytes, despite absent Akt phosphorylation. Our data point to the glucagon-induced decrease in bioactive IGF-1 levels as a mechanism through which glucagon induces GH secretion. This insulin-independent reduction is related to increased IGFBP-1 and IGFBP-2 levels, which are most likely mediated via activation of the FOXO/mTOR (mechanistic target of rapamycin) pathway. Copyright © 2017 Endocrine Society

  19. Androgen receptor activation integrates complex transcriptional effects in osteoblasts, involving the growth factors TGF-β and IGF-I, and transcription factor C/EBPδ.

    Science.gov (United States)

    McCarthy, Thomas L; Centrella, Michael

    2015-11-15

    Osteoblasts respond to many growth factors including IGF-I and TGF-β, which themselves are sensitive to other bone growth regulators. Here we show that IGF-I gene promoter activity in prostaglandin E2 (PGE2) induced osteoblasts is suppressed by dihydrotestosterone (DHT) through an essential C/EBP response element (RE) in exon 1 of the igf1 gene. Inhibition by DHT fails to occur when the androgen receptor (AR) gene is mutated within its DNA binding domain. Correspondingly, DHT activated AR inhibits gene transactivation by C/EBPδ, and transgenic C/EBPδ expression inhibits AR activity. Inhibition by DHT persists when upstream Smad and Runx REs in the IGF-I gene promoter are mutated. TGF-β also enhances IGF-I gene promoter activity, although modestly relative to PGE2, and independently of the C/EBP, Smad, or Runx REs. Still, DHT suppresses TGF-β induced IGF-I promoter activity, but not its effects on DNA or collagen synthesis. Notably, DHT suppresses plasminogen activator inhibitor gene promoter activity, but synergistically increases Smad dependent gene promoter activity in TGF-β induced cells, which are differentially sensitive to AR mutations and the AR co-regulator ARA55. Finally, although the PGE2 sensitive C/EBP RE in the igf1 gene is not essential for basal TGF-β induction, C/EBPδ activity through this site is potently enhanced by TGF-β. Thus DHT suppresses the PGE2 and TGF-β induced IGF-I gene promoter and differentiates other aspects of TGF-β activity in osteoblasts. Our results extend the complex interactions among local and systemic bone growth regulators to DHT, and predict complications from anabolic steroid use in other DHT sensitive tissues. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Long-term insulin-like growth factor-I expression in skeletal muscles attenuates the enhanced in vitro proliferation ability of the resident satellite cells in transgenic mice

    Science.gov (United States)

    Chakravarthy, M. V.; Fiorotto, M. L.; Schwartz, R. J.; Booth, F. W.

    2001-01-01

    Insulin-like growth factor-I (IGF-I) overexpression for 1-month in mouse skeletal muscle increases satellite cell proliferation potential. However, it is unknown whether this beneficial enhancement by IGF-I expression would persist over a longer-term duration in aged mice. This is an important issue to address if a prolonged course of IGF-I is to be used clinically in muscle-wasting conditions where satellite cells may become limiting. Using the IGF-I transgenic (IGF-I Tg) mouse that selectively expresses the IGF-I transgene in striated muscles, we found that 18-months of continuous IGF-I overexpression led to a loss in the enhanced in vitro proliferative capacity of satellite cells from Tg skeletal muscles. Also 18-month-old IGF-I Tg satellite cells lost the enhanced BrdU incorporation, greater pRb and Akt phosphorylations, and decreased p27(Kip1) levels initially observed in cells from 1-month-old IGF-I Tg mice. The levels of those biochemical markers reverted to similar values seen in the 18-months WT littermates. These findings, therefore, suggest that there is no further beneficial effect on enhancing satellite cell proliferation ability with persistent long-term expression of IGF-I in skeletal muscles of these transgenic mice.

  1. Insulin increase in MAP kinase phosphorylation is shifted to early time-points by overexpressing APS, while Akt phosphorylation is not influenced.

    Science.gov (United States)

    Onnockx, Sheela; Xie, Jingwei; Degraef, Chantal; Erneux, Christophe; Pirson, Isabelle

    2009-09-10

    Upon insulin stimulation, the adaptor protein APS is recruited to the insulin receptor and tyrosine phosphorylated. APS initiates the insulin-induced TC10 cascade which participates to GLUT4 translocation to the plasma membrane. Nevertheless, the molecular mechanism that governs APS and its SH2 and PH domains action on the insulin transduction cascade is not yet fully understood. Here, we show that APS co-immunoprecipitates with the class I PI 3-kinase regulatory subunit p85, through its SH2 domain but that APS does not modulate neither PtdIns(3,4,5)P3 levels nor Akt phosphorylation provoked by insulin. We have confirmed a previously described positive effect of APS overexpression on insulin-induced MAPK phosphorylation upregulation. Consequently, we analyzed the role of SH2 and PH domains of APS in the APS increased MAPK phosphorylation observed upon insulin stimulation and correlated this with the membrane localization of the protein. The effect observed on MAPK phosphorylation requires the intact PH binding domain of APS as well as its SH2 domain.

  2. Insulin-Like Growth Factor-I Induces Arginase Activity in Leishmania amazonensis Amastigote-Infected Macrophages through a Cytokine-Independent Mechanism

    Directory of Open Access Journals (Sweden)

    Celia Maria Vieira Vendrame

    2014-01-01

    Full Text Available Leishmania (Leishmania amazonensis exhibits peculiarities in its interactions with hosts. Because amastigotes are the primary form associated with the progression of infection, we studied the effect of insulin-like growth factor (IGF-I on interactions between L. (L. amazonensis amastigotes and macrophages. Upon stimulation of infected macrophages with IGF-I, we observed decreased nitric oxide production but increased arginase expression and activity, which lead to increased parasitism. However, stimulation of amastigote-infected macrophages with IGF-I did not result in altered cytokine levels compared to unstimulated controls. Because IGF-I is present in tissue fluids and also within macrophages, we examined the possible effect of this factor on phosphatidylserine (PS exposure on amastigotes, seen previously in tissue-derived amastigotes leading to increased parasitism. Stimulation with IGF-I induced PS exposure on amastigotes but not on promastigotes. Using a PS-liposome instead of amastigotes, we observed that the PS-liposome but not the control phosphatidylcholine-liposome led to increased arginase activity in macrophages, and this process was not blocked by anti-TGF-β antibodies. Our results suggest that in L. (L. amazonensis amastigote-infected macrophages, IGF-I induces arginase activity directly in amastigotes and in macrophages through the induction of PS exposure on amastigotes in the latter, which could lead to the alternative activation of macrophages through cytokine-independent mechanisms.

  3. Role of IGF-1/IGF-1R in regulation of invasion in DU145 prostate cancer cells

    Directory of Open Access Journals (Sweden)

    Setya Hemani

    2008-07-01

    Full Text Available Abstract Background Prostate cancer progression to androgen independence is the primary cause of mortality by this tumor type. The IGF-1/IGF-1R axis is well known to contribute to prostate cancer initiation, but its contribution to invasiveness and the downstream signalling mechanisms that are involved are unclear at present. Results We examined the invasive response of androgen independent DU145 prostate carcinoma cells to IGF-1 stimulation using Matrigel assays. We then examined the signaling mechanisms and protease activities that are associated with this response. IGF-1 significantly increased the invasive capacity of DU145 cells in vitro, and this increase was inhibited by blocking IGF-1R. We further demonstrated that specific inhibitors of the MAPK and PI3-K pathways decrease IGF-1-mediated invasion. To determine potential molecular mechanisms for this change in invasive capacity, we examined changes in expression and activity of matrix metalloproteinases. We observed that IGF-1 increases the enzymatic activity of MMP-2 and MMP-9 in DU145 cells. These changes in activity are due to differences in expression in the case of MMP-9 but not in the case of MMP-2. This observation is corroborated by the fact that correlated changes of expression in a regulator of MMP-2, TIMP-2, were also seen. Conclusion This work identifies a specific effect of IGF-1 on the invasive capacity of DU145 prostate cancer cells, and furthermore delineates mechanisms that contribute to this effect.

  4. Loop-Loop Interactions Regulate KaiA-Stimulated KaiC Phosphorylation in the Cyanobacterial KaiABC Circadian Clock

    Energy Technology Data Exchange (ETDEWEB)

    Egli, Martin [Vanderbilt Univ., Nashville, TN (United States); Pattanayek, Rekha [Vanderbilt Univ., Nashville, TN (United States); Sheehan, Jonathan H. [Vanderbilt Univ., Nashville, TN (United States); Xu, Yao [Vanderbilt Univ., Nashville, TN (United States); Mori, Tetsuya [Vanderbilt Univ., Nashville, TN (United States); Smith, Jarrod A. [Vanderbilt Univ., Nashville, TN (United States); Johnson, Carl H. [Vanderbilt Univ., Nashville, TN (United States)

    2013-01-25

    We found that the Synechococcus elongatus KaiA, KaiB, and KaiC proteins in the presence of ATP generate a post-translational oscillator that runs in a temperature-compensated manner with a period of 24 h. KaiA dimer stimulates phosphorylation of KaiC hexamer at two sites per subunit, T432 and S431, and KaiB dimers antagonize KaiA action and induce KaiC subunit exchange. Neither the mechanism of KaiA-stimulated KaiC phosphorylation nor that of KaiB-mediated KaiC dephosphorylation is understood in detail at present. We demonstrate here that the A422V KaiC mutant sheds light on the former mechanism. It was previously reported that A422V is less sensitive to dark pulse-induced phase resetting and has a reduced amplitude of the KaiC phosphorylation rhythm in vivo. A422 maps to a loop (422-loop) that continues toward the phosphorylation sites. By pulling on the C-terminal peptide of KaiC (A-loop), KaiA removes restraints from the adjacent 422-loop whose increased flexibility indirectly promotes kinase activity. We found in the crystal structure that A422V KaiC lacks phosphorylation at S431 and exhibits a subtle, local conformational change relative to wild-type KaiC. Molecular dynamics simulations indicate higher mobility of the 422-loop in the absence of the A-loop and mobility differences in other areas associated with phosphorylation activity between wild-type and mutant KaiCs. Finally, the A-loop–422-loop relay that informs KaiC phosphorylation sites of KaiA dimer binding propagates to loops from neighboring KaiC subunits, thus providing support for a concerted allosteric mechanism of phosphorylation.

  5. Peripheral blood aspirates overexpressing IGF-I via rAAV gene transfer undergo enhanced chondrogenic differentiation processes.

    Science.gov (United States)

    Frisch, Janina; Orth, Patrick; Rey-Rico, Ana; Venkatesan, Jagadeesh Kumar; Schmitt, Gertrud; Madry, Henning; Kohn, Dieter; Cucchiarini, Magali

    2017-11-01

    Implantation of peripheral blood aspirates induced towards chondrogenic differentiation upon genetic modification in sites of articular cartilage injury may represent a powerful strategy to enhance cartilage repair. Such a single-step approach may be less invasive than procedures based on the use of isolated or concentrated MSCs, simplifying translational protocols in patients. In this study, we provide evidence showing the feasibility of overexpressing the mitogenic and pro-anabolic insulin-like growth factor I (IGF-I) in human peripheral blood aspirates via rAAV-mediated gene transfer, leading to enhanced proliferative and chondrogenic differentiation (proteoglycans, type-II collagen, SOX9) activities in the samples relative to control (reporter rAAV-lacZ) treatment over extended periods of time (at least 21 days, the longest time-point evaluated). Interestingly, IGF-I gene transfer also triggered hypertrophic, osteo- and adipogenic differentiation processes in the aspirates, suggesting that careful regulation of IGF-I expression may be necessary to contain these events in vivo. Still, the current results demonstrate the potential of targeting human peripheral blood aspirates via therapeutic rAAV transduction as a novel, convenient tool to treat articular cartilage injuries. © 2017 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

  6. Effects of High Intensity Interval Training on Plasma Levels of GH and IGF-I

    OpenAIRE

    Seyyed Mahmoud Hejazi

    2017-01-01

    Introduction: It is well-recognized that exercise has a significant impact on the GH/IGF system but less is known about the effects of HIIT on this axis. Aim of the present study was to evaluate the effect of ten weeks of HIIT on plasma levels of GH and IGF-I in healthy men. Methods: Twenty young men (age 23.34 ± 2.56 weight 72.47 ± 12.01 height 174.10 ± 5.75) recruited and randomly assigned into control (n=10) and HIIT (n=12) groups. HIIT protocol was started with 4 cycles. Then,...

  7. Evidence for the possible biological significance of the igf-1 gene alternative splicing in prostate cancer

    Directory of Open Access Journals (Sweden)

    Anastassios ePhilippou

    2013-03-01

    Full Text Available Insulin-like growth factor I (IGF-I has been implicated in the pathogenesis of prostate cancer (PCa, since it plays a key role in cell proliferation, differentiation and apoptosis. The IGF-I actions are mediated mainly via its binding to the type I IGF receptor (IGF-IR, however IGF-I signaling via insulin receptor (IR and hybrid IGF-I/IR is also evident. Different IGF-I mRNA splice variants, namely IGF-IEa, IGF-IEb and IGF-IEc, are expressed in human cells and tissues. These transcripts encode several IGF-I precursor proteins which contain the same bioactive product (mature IGF-I, however, they differ by the length of their signal peptides on the amino-terminal end and the structure of the extension peptides (E-peptides on the carboxy-terminal end. There is an increasing interest in the possible different role of the IGF-I transcripts and their respective non-(matureIGF-I products in the regulation of distinct biological activities. Moreover, there is strong evidence of a differential expression profile of the IGF-I splice variants in normal vs. PCa tissues and PCa cells, implying that the expression pattern of the various IGF-I transcripts and their respective protein products may possess different functions in cancer biology. Herein, the evidence that the IGF-IEc transcript regulates PCa growth via Ec-peptide specific and IGF-IR/IR-independent signaling is discussed.

  8. IGF-1 protects SH-SY5Y cells against MPP+-induced apoptosis via PI3K/PDK-1/Akt pathway.

    Science.gov (United States)

    Kim, Chanyang; Park, Seungjoon

    2018-03-01

    Insulin-like growth factor (IGF)-1 is a well-known anti-apoptotic pro-survival factor and phosphatidylinositol-3-kinase (PI3K)/Akt pathway is linked to cell survival induced by IGF-1. It is also reported that Akt signaling is modulated by 3-phosphoinositide-dependent kinase-1 (PDK1). In the current study, we investigated whether the anti-apoptotic effect of IGF-1 in SH-SY5Y cells exposed to 1-methyl-4-phenylpyridinium (MPP + ) is associated with the activity of PI3K/PDK1/Akt pathway. Treatment of cells with IGF-1 inhibited MPP + -induced apoptotic cell death. IGF-1-induced activation of Akt and the protective effect of IGF-1 on MPP + -induced apoptosis were abolished by chemical inhibition of PDK1 (GSK2334470) or PI3K (LY294002). The phosphorylated levels of Akt and PDK1 were significantly suppressed after MPP + exposure, while IGF-1 treatment completely restored MPP+-induced reductions in phosphorylation. IGF-1 protected cells from MPP + insult by suppressing intracellular reactive oxygen species (ROS) production and malondialdehyde levels and increasing superoxide dismutase activity. Mitochondrial ROS levels were also increased during MPP + exposure, which were attenuated by IGF-1 treatment. In addition, IGF-1-treated cells showed increased activities of succinate dehydrogenase and citrate synthase, stabilization of mitochondrial transmembrane potential, increased ratio of Bcl-2 to Bax, prevention of cytochrome c release and inhibition of caspase-3 activation with PARP cleavage. Furthermore, the protective effects of IGF-1 on oxidative stress and mitochondrial dysfunction were attenuated when cells were preincubated with GSK2334470 or LY294002. Our data suggest that IGF-1 protects SH-SY5Y cells against MPP + -associated oxidative stress by preserving mitochondrial integrity and inhibiting mitochondrial apoptotic cascades via the activation of PI3K/PDK1/Akt pathway. © 2018 The authors.

  9. The Effects of Systemic IGF-I on the Arterial Anastomosis in Rats

    Directory of Open Access Journals (Sweden)

    Baris Keklik

    2014-04-01

    Full Text Available Objective: In this study, we aimed to document the effects of a well-known agent and mdash; and ldquo;insulin-like growth factor (IGF-I and rdquo; and mdash; on the microvascular anastomosis site. Methods: Sixteen Sprague-Dawley rats were used in this study. The rats were classified randomly into two equally numbered groups (eight rats each: the control (Group 1 and the experiment group (Group 2. The femoral artery was dissected completely in all rats. Following division of the artery, anastomoses were conducted with microvascular techniques. Forty-five minutes after the anastomoses, an Acland milking test was performed in order to check the patency and the first surgical session was terminated. In the second stage, LONG and reg; R3 IGF-I human (Sigma-Aldrich, St. Louis, Missouri, United States solution was introduced to Group 2 (experimental group intraperitoneally in doses of 2 mg/kg on the day of the surgery in addition to the third and seventh days postoperatively. On the 4th postoperative week, the patency of the anastomoses was evaluated with the Acland milking test. In addition, one centimeter of a vascular segment including the anastomosis site was excised and stained with hematoxylin-eosin. They were evaluated for edema, inflammation, vascular wall injury, intimal hyperplasia, medial atrophy, thrombus, calcification, foreign body reactions, and the endothelial proliferation. Results: The Acland milking test showed a 100% vascular patency in both groups. A statistically significant difference was found between the experimental and control groups in terms of edema and vascular wall injury (p0.05. Conclusion: Under the light of the obtained data, IGF-I was effective in preventing the edema and vascular wall injury at the anastomosis site. However, the net positive clinical effect on anastomosis patency necessitates further studies. [Arch Clin Exp Surg 2014; 3(2.000: 87-93

  10. Effect of oral alpha-tocopherol and zinc on plasma status, IGF-I levels, weight gain and immune response in young calves

    DEFF Research Database (Denmark)

    Sehested, J.; Jørgensen, C.; Mortensen, S.B.

    2004-01-01

    IGF-I levels generally increased from birth to week 8, but were not affected by Zn or vit. E. Daily weight gain was highest in the Zn group, but this was not related to an increased IGF-I level. The vit. E group responded earlier than the Zn and control groups to the tetanus vaccination....

  11. I, IGF-II and IGFBP-II with production traits in breeder hens

    African Journals Online (AJOL)

    USER

    2010-02-08

    Feb 8, 2010 ... have shown that circulating IGF-I affects growth rate, body composition and lipid metabolism in ... about 2500 birds of two sexes were kept to produce hatching eggs and chicks produced from these eggs ... Economic indexes are calculated for these traits and birds of two sexes are selected based on their ...

  12. Insulin-like growth factor-1 (IGF-1) promotes primordial follicle growth and reduces DNA fragmentation through the phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) signalling pathway.

    Science.gov (United States)

    Bezerra, Maria É S; Barberino, Ricássio S; Menezes, Vanúzia G; Gouveia, Bruna B; Macedo, Taís J S; Santos, Jamile M S; Monte, Alane P O; Barros, Vanessa R P; Matos, Maria H T

    2018-05-30

    We investigated the effects of insulin-like growth factor 1 (IGF-1) on the morphology and follicular activation of ovine preantral follicles cultured in situ and whether the phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) pathway is involved in IGF-1 action in the sheep ovary. Ovine ovarian fragments were fixed for histological and terminal deoxynucleotidyl transferase dUTP nick-end labelling (TUNEL) analyses (fresh control) or cultured in supplemented alpha-minimum essential medium (α-MEM+; control) or α-MEM+ with IGF-1 (1, 10, 50, 100 or 200ngmL-1) for 7 days. Follicles were classified as normal or atretic, primordial or growing and the oocyte and follicle diameters were measured. DNA fragmentation was evaluated by TUNEL assay. Proliferating cell nuclear antigen (PCNA) immunohistochemistry was performed on the fresh control, α-MEM+ and 100ngmL-1 IGF-1 samples. Inhibition of PI3K activity was performed through pretreatment with the PI3K inhibitor LY294002 and phosphorylated AKT (pAKT) expression was analysed after culture in the absence or presence of LY294002. IGF-1 at 100ngmL-1 increased (PIGF-1. LY294002 significantly inhibited follicular activation stimulated by α-MEM+ and 100ngmL-1 IGF-1 and reduced pAKT expression in follicles. Overall, IGF-1 at 100ngmL-1 promoted primordial follicle activation, cell proliferation and reduced DNA fragmentation after in situ culture through the PI3K/AKT pathway.

  13. Effect of recombinant human insulin-like growth factor-I on progression of ALS. A placebo-controlled study. The North America ALS/IGF-I Study Group.

    Science.gov (United States)

    Lai, E C; Felice, K J; Festoff, B W; Gawel, M J; Gelinas, D F; Kratz, R; Murphy, M F; Natter, H M; Norris, F H; Rudnicki, S A

    1997-12-01

    The objective of this study was to investigate the safety and efficacy of recombinant human insulinlike growth factor-I (rhIGF-I) in the treatment of sporadic ALS. A double-blind, placebo-controlled, randomized study of 266 patients was conducted at eight centers in North America. Placebo or rhIGF-I (0.05 mg/kg/day or 0.10 mg/kg/day) was administered for 9 months. The primary outcome measure was disease symptom progression, assessed by the rate of change (per patient slope) in the Appel ALS rating scale total score. The Sickness Impact Profile (SIP), a patient-perceived, health-related quality of life assessment, was a secondary outcome variable. Progression of functional impairment in patients receiving high-dose (0.10 mg/kg/day) rhIGF-I was 26% slower than in patients receiving placebo (p = 0.01). The high-dose treatment group was less likely to terminate the study due to protocol-defined markers of disease symptom progression, and members in this group exhibited a slower decline in quality of life, as assessed by the SIP. Patients receiving 0.05 mg/kg/day of rhIGF-I exhibited trends similar to those associated with high-dose treatment, suggesting a dose-dependent response. The incidence of clinically significant adverse experiences was comparable among the three treatment groups. Recombinant human insulin-like growth factor-I slowed the progression of functional impairment and the decline in health-related quality of life in patients with ALS with no medically important adverse effects.

  14. TNNI3K is a novel mediator of myofilament function and phosphorylates cardiac troponin I

    International Nuclear Information System (INIS)

    Wang, Hui; Wang, Lin; Song, Li; Zhang, Yan-Wan; Ye, Jue; Xu, Rui-Xia; Shi, Na; Meng, Xian-Min

    2013-01-01

    The phosphorylation of cardiac troponin I (cTnI) plays an important role in the contractile dysfunction associated with heart failure. Human cardiac troponin I-interacting kinase (TNNI3K) is a novel cardiac-specific functional kinase that can bind to cTnI in a yeast two-hybrid screen. The purpose of this study was to investigate whether TNNI3K can phosphorylate cTnI at specific sites and to examine whether the phosphorylation of cTnI caused by TNNI3K can regulate cardiac myofilament contractile function. Co-immunoprecipitation was performed to confirm that TNNI3K could interact with cTnI. Kinase assays further indicated that TNNI3K did not phosphorylate cTnI at Ser23/24 and Ser44, but directly phosphorylated Ser43 and Thr143 in vitro. The results obtained for adult rat cardiomyocytes also indicated that enhanced phosphorylation of cTnI at Ser43 and Thr143 correlated with rTNNI3K (rat TNNI3K) overexpression, and phosphorylation was reduced when rTNNI3K was knocked down. To determine the contractile function modulated by TNNI3K-mediated phosphorylation of cTnI, cardiomyocyte contraction was studied in adult rat ventricular myocytes. The contraction of cardiomyocytes increased with rTNNI3K overexpression and decreased with rTNNI3K knockdown. We conclude that TNNI3K may be a novel mediator of cTnI phosphorylation and contribute to the regulation of cardiac myofilament contraction function

  15. Prolonged inorganic arsenite exposure suppresses insulin-stimulated AKT S473 phosphorylation and glucose uptake in 3T3-L1 adipocytes: Involvement of the adaptive antioxidant response

    International Nuclear Information System (INIS)

    Xue, Peng; Hou, Yongyong; Zhang, Qiang; Woods, Courtney G.; Yarborough, Kathy; Liu, Huiyu; Sun, Guifan; Andersen, Melvin E.; Pi, Jingbo

    2011-01-01

    Highlights: → In 3T3-L1 adipocytes iAs 3+ decreases insulin-stimulated glucose uptake. → iAs 3+ attenuates insulin-induced phosphorylation of AKT S473. → iAs 3+ activates the cellular adaptive oxidative stress response. → iAs 3+ impairs insulin-stimulated ROS signaling. → iAs 3+ decreases expression of adipogenic genes and GLUT4. -- Abstract: There is growing evidence that chronic exposure of humans to inorganic arsenic, a potent environmental oxidative stressor, is associated with the incidence of type 2 diabetes (T2D). One critical feature of T2D is insulin resistance in peripheral tissues, especially in mature adipocytes, the hallmark of which is decreased insulin-stimulated glucose uptake (ISGU). Despite the deleterious effects of reactive oxygen species (ROS), they have been recognized as a second messenger serving an intracellular signaling role for insulin action. Nuclear factor erythroid 2-related factor 2 (NRF2) is a central transcription factor regulating cellular adaptive response to oxidative stress. This study proposes that in response to arsenic exposure, the NRF2-mediated adaptive induction of endogenous antioxidant enzymes blunts insulin-stimulated ROS signaling and thus impairs ISGU. Exposure of differentiated 3T3-L1 cells to low-level (up to 2 μM) inorganic arsenite (iAs 3+ ) led to decreased ISGU in a dose- and time-dependent manner. Concomitant to the impairment of ISGU, iAs 3+ exposure significantly attenuated insulin-stimulated intracellular ROS accumulation and AKT S473 phosphorylation, which could be attributed to the activation of NRF2 and induction of a battery of endogenous antioxidant enzymes. In addition, prolonged iAs 3+ exposure of 3T3-L1 adipocytes resulted in significant induction of inflammatory response genes and decreased expression of adipogenic genes and glucose transporter type 4 (GLUT4), suggesting chronic inflammation and reduction in GLUT4 expression may also be involved in arsenic-induced insulin resistance in

  16. Prolonged inorganic arsenite exposure suppresses insulin-stimulated AKT S473 phosphorylation and glucose uptake in 3T3-L1 adipocytes: Involvement of the adaptive antioxidant response

    Energy Technology Data Exchange (ETDEWEB)

    Xue, Peng [The Hamner Institutes for Health Sciences, Research Triangle Park, NC 27709 (United States); School of Public Health, China Medical University, Shenyang 110001 (China); Hou, Yongyong; Zhang, Qiang; Woods, Courtney G.; Yarborough, Kathy; Liu, Huiyu [The Hamner Institutes for Health Sciences, Research Triangle Park, NC 27709 (United States); Sun, Guifan [School of Public Health, China Medical University, Shenyang 110001 (China); Andersen, Melvin E. [The Hamner Institutes for Health Sciences, Research Triangle Park, NC 27709 (United States); Pi, Jingbo, E-mail: jpi@thehamner.org [The Hamner Institutes for Health Sciences, Research Triangle Park, NC 27709 (United States)

    2011-04-08

    Highlights: {yields} In 3T3-L1 adipocytes iAs{sup 3+} decreases insulin-stimulated glucose uptake. {yields} iAs{sup 3+} attenuates insulin-induced phosphorylation of AKT S473. {yields} iAs{sup 3+} activates the cellular adaptive oxidative stress response. {yields} iAs{sup 3+} impairs insulin-stimulated ROS signaling. {yields} iAs{sup 3+} decreases expression of adipogenic genes and GLUT4. -- Abstract: There is growing evidence that chronic exposure of humans to inorganic arsenic, a potent environmental oxidative stressor, is associated with the incidence of type 2 diabetes (T2D). One critical feature of T2D is insulin resistance in peripheral tissues, especially in mature adipocytes, the hallmark of which is decreased insulin-stimulated glucose uptake (ISGU). Despite the deleterious effects of reactive oxygen species (ROS), they have been recognized as a second messenger serving an intracellular signaling role for insulin action. Nuclear factor erythroid 2-related factor 2 (NRF2) is a central transcription factor regulating cellular adaptive response to oxidative stress. This study proposes that in response to arsenic exposure, the NRF2-mediated adaptive induction of endogenous antioxidant enzymes blunts insulin-stimulated ROS signaling and thus impairs ISGU. Exposure of differentiated 3T3-L1 cells to low-level (up to 2 {mu}M) inorganic arsenite (iAs{sup 3+}) led to decreased ISGU in a dose- and time-dependent manner. Concomitant to the impairment of ISGU, iAs{sup 3+} exposure significantly attenuated insulin-stimulated intracellular ROS accumulation and AKT S473 phosphorylation, which could be attributed to the activation of NRF2 and induction of a battery of endogenous antioxidant enzymes. In addition, prolonged iAs{sup 3+} exposure of 3T3-L1 adipocytes resulted in significant induction of inflammatory response genes and decreased expression of adipogenic genes and glucose transporter type 4 (GLUT4), suggesting chronic inflammation and reduction in GLUT4

  17. Effect Of IGF-1 On Expression Of Gh Receptor, IGF-1, IGF-1 ...

    African Journals Online (AJOL)

    ... and the skin expression of growth hormone receptor (GHR), insulin-like growth factor1 (IGF-1), insulin-like growth factor receptor (IGF- R), KAP3.2 and KAP6-1 mRNA were measured by RT-PCR. The results indicated that IGF-1 could degrade GHR gene expression, have no effect of IGF-1 and IGF-1R gene expression, ...

  18. Compensatory insulin receptor (IR) activation on inhibition of insulin-like growth factor-1 receptor (IGF-1R): rationale for cotargeting IGF-1R and IR in cancer.

    Science.gov (United States)

    Buck, Elizabeth; Gokhale, Prafulla C; Koujak, Susan; Brown, Eric; Eyzaguirre, Alexandra; Tao, Nianjun; Rosenfeld-Franklin, Maryland; Lerner, Lorena; Chiu, M Isabel; Wild, Robert; Epstein, David; Pachter, Jonathan A; Miglarese, Mark R

    2010-10-01

    Insulin-like growth factor-1 receptor (IGF-1R) is a receptor tyrosine kinase (RTK) and critical activator of the phosphatidylinositol 3-kinase-AKT pathway. IGF-1R is required for oncogenic transformation and tumorigenesis. These observations have spurred anticancer drug discovery and development efforts for both biological and small-molecule IGF-1R inhibitors. The ability for one RTK to compensate for another to maintain tumor cell viability is emerging as a common resistance mechanism to antitumor agents targeting individual RTKs. As IGF-1R is structurally and functionally related to the insulin receptor (IR), we asked whether IR is tumorigenic and whether IR-AKT signaling contributes to resistance to IGF-1R inhibition. Both IGF-1R and IR(A) are tumorigenic in a mouse mammary tumor model. In human tumor cells coexpressing IGF-1R and IR, bidirectional cross talk was observed following either knockdown of IR expression or treatment with a selective anti-IGF-1R antibody, MAB391. MAB391 treatment resulted in a compensatory increase in phospho-IR, which was associated with resistance to inhibition of IRS1 and AKT. In contrast, treatment with OSI-906, a small-molecule dual inhibitor of IGF-1R/IR, resulted in enhanced reduction in phospho-IRS1/phospho-AKT relative to MAB391. Insulin or IGF-2 activated the IR-AKT pathway and decreased sensitivity to MAB391 but not to OSI-906. In tumor cells with an autocrine IGF-2 loop, both OSI-906 and an anti-IGF-2 antibody reduced phospho-IR/phospho-AKT, whereas MAB391 was ineffective. Finally, OSI-906 showed superior efficacy compared with MAB391 in human tumor xenograft models in which both IGF-1R and IR were phosphorylated. Collectively, these data indicate that cotargeting IGF-1R and IR may provide superior antitumor efficacy compared with targeting IGF-1R alone.

  19. Differential Regulation of Hippocampal IGF-1-Associated Signaling Proteins by Dietary Restriction in Aging Mouse.

    Science.gov (United States)

    Hadem, Ibanylla Kynjai Hynniewta; Sharma, Ramesh

    2017-08-01

    Time-dependent alterations in several biological processes of an organism may be characterized as aging. One of the effects of aging is the decline in cognitive functions. Dietary restriction (DR), an intervention where the consumption of food is lessened but without malnutrition, is a well-established mechanism that has a wide range of important outcomes including improved health span, delayed aging, and extension of lifespan of various species. It also plays a beneficial role in protecting against age-dependent deterioration of cognitive functions, and has neuroprotective properties against neurodegenerative diseases. Insulin-like growth factor (IGF)-1 plays an important role in the regulation of cellular and tissue functions, and relating to the aging process the most important pathway of IGF-1 is the phosphatidylinositol 3-kinase (PI3K) and protein kinase B (Akt/PKB) signaling cascade. Although many have studied the changes in the level of IGF-1 and its effect on neural proliferation, the downstream signaling proteins have not been fully elucidated. Hence in the present investigation, the IGF-1 gene expression and the normal endogenous levels of IGF1R (IGF-1 receptor), PI3K, Akt, pAkt, and pFoxO in the hippocampus of young, adult, and old mice were determined using real-time PCR and Western blot analyses. The effects of DR on these protein levels were also studied. Results showed a decrease in the levels of IGF-1, IGF1R, PI3K, and pAkt, while pFoxO level increased with respect to age. Under DR, these protein levels are maintained in adult mice, but old mice displayed diminished expression levels of these proteins as compared to ad libitum-fed mice. Maintenance of PI3K/Akt pathway results in the phosphorylation of FoxOs, necessary for the enhancement of neural proliferation and survival in adult mice. The down-regulation of IGF-I signaling, as observed in old mice, leads to increasing the activity of FoxO factors that may be important for the neuroprotective

  20. R1507, an Anti-Insulin-Like Growth Factor-1 Receptor (IGF-1R) Antibody, and EWS/FLI-1 siRNA in Ewing's Sarcoma: Convergence at the IGF/IGFR/Akt Axis

    Science.gov (United States)

    Rodon, Jordi; Sun, Michael; Kuenkele, Klaus-Peter; Parsons, Henrique A.; Trent, Jonathan C.; Kurzrock, Razelle

    2011-01-01

    A subset of patients with Ewing's sarcoma responds to anti-insulin-like growth factor-1 receptor (IGF-1R) antibodies. Mechanisms of sensitivity and resistance are unknown. We investigated whether an anti-IGF-1R antibody acts via a pathway that could also be suppressed by small interfering (si) RNA against the EWS/FLI-1 fusion protein, the hallmark of Ewing's sarcoma. The growth of two Ewing's sarcoma cell lines (TC-32 and TC-71) was inhibited by the fully human anti-IGF-1R antibody, R1507 (clonogenic and MTT assays). TC-32 and TC-71 cells express high levels of IGF-2, while RD-ES and A4573 Ewing's cell lines, which were less responsive to R1507 in our assays, express low or undetectable IGF-2, respectively. TC-71 cells also expressed high levels of IGF-1R, and R1507 decreased steady-state levels of this receptor by internalization/degradation, an effect which was associated with a decrease in p-IGF-1R, p-IRS-1, and p-Akt. EWS/FLI-1 siRNA also decreased p-Akt, due to its ability to increase IGF-BP3 levels and subsequently decrease IGF-1 and IGF-2 levels, thus inhibiting signaling through p-IGF-1R. This inhibition correlated with growth suppression and apoptosis. The attenuation of Akt activation was confirmed in TC-71 and HEK-293 (human embryonic kidney) cells by transfecting them with IGF-1R siRNA. We conclude that antibodies and siRNA to IGF-1R, as well as siRNA to EWS/FLI-1, act via intersecting IGF/IGF-1R signals that suppress a common point in this pathway, namely the phosphorylation of Akt. PMID:22022506

  1. R1507, an anti-insulin-like growth factor-1 receptor (IGF-1R antibody, and EWS/FLI-1 siRNA in Ewing's sarcoma: convergence at the IGF/IGFR/Akt axis.

    Directory of Open Access Journals (Sweden)

    Helen J Huang

    Full Text Available A subset of patients with Ewing's sarcoma responds to anti-insulin-like growth factor-1 receptor (IGF-1R antibodies. Mechanisms of sensitivity and resistance are unknown. We investigated whether an anti-IGF-1R antibody acts via a pathway that could also be suppressed by small interfering (si RNA against the EWS/FLI-1 fusion protein, the hallmark of Ewing's sarcoma. The growth of two Ewing's sarcoma cell lines (TC-32 and TC-71 was inhibited by the fully human anti-IGF-1R antibody, R1507 (clonogenic and MTT assays. TC-32 and TC-71 cells express high levels of IGF-2, while RD-ES and A4573 Ewing's cell lines, which were less responsive to R1507 in our assays, express low or undetectable IGF-2, respectively. TC-71 cells also expressed high levels of IGF-1R, and R1507 decreased steady-state levels of this receptor by internalization/degradation, an effect which was associated with a decrease in p-IGF-1R, p-IRS-1, and p-Akt. EWS/FLI-1 siRNA also decreased p-Akt, due to its ability to increase IGF-BP3 levels and subsequently decrease IGF-1 and IGF-2 levels, thus inhibiting signaling through p-IGF-1R. This inhibition correlated with growth suppression and apoptosis. The attenuation of Akt activation was confirmed in TC-71 and HEK-293 (human embryonic kidney cells by transfecting them with IGF-1R siRNA. We conclude that antibodies and siRNA to IGF-1R, as well as siRNA to EWS/FLI-1, act via intersecting IGF/IGF-1R signals that suppress a common point in this pathway, namely the phosphorylation of Akt.

  2. Polymorphisms of genes coding for ghrelin and its receptor in relation to anthropometry, circulating levels of IGF-I and IGFBP-3, and breast cancer risk: a case-control study nested within the European Prospective Investigation into Cancer and Nutrition (EPIC).

    Science.gov (United States)

    Dossus, Laure; McKay, James D; Canzian, Federico; Wilkening, Stefan; Rinaldi, Sabina; Biessy, Carine; Olsen, Anja; Tjønneland, Anne; Jakobsen, Marianne U; Overvad, Kim; Clavel-Chapelon, Françoise; Boutron-Ruault, Marie-Christine; Fournier, Agnes; Linseisen, Jakob; Lukanova, Annekatrin; Boeing, Heiner; Fisher, Eva; Trichopoulou, Antonia; Georgila, Christina; Trichopoulos, Dimitrios; Palli, Domenico; Krogh, Vittorio; Tumino, Rosario; Vineis, Paolo; Quirós, José Ramon; Sala, Núria; Martínez-García, Carmen; Dorronsoro, Miren; Chirlaque, Maria-Dolores; Barricarte, Aurelio; van Duijnhoven, Fränzel J B; Bueno-de-Mesquita, H B; van Gils, Carla H; Peeters, Petra H M; Hallmans, Göran; Lenner, Per; Bingham, Sheila; Khaw, Kay Tee; Key, Tim J; Travis, Ruth C; Ferrari, Pietro; Jenab, Mazda; Riboli, Elio; Kaaks, Rudolf

    2008-07-01

    Ghrelin, an endogenous ligand for the growth hormone secretagogue receptor, has two major functions: the stimulation of the growth hormone production and the stimulation of food intake. Accumulating evidence also suggests a role of ghrelin in cancer development. We conducted a case-control study on 1359 breast cancer cases and 2389 matched controls, nested within the European Prospective Investigation into Cancer and Nutrition, to examine the association of common genetic variants in the genes coding for ghrelin (GHRL) and its receptor (GHSR) with anthropometric measures, circulating insulin growth factor I (IGF-I) and insulin-like growth factor-binding protein 3 and breast cancer risk. Pair-wise tagging was used to select the 15 polymorphisms that represent the majority of common genetic variants across the GHRL and GHSR genes. A significant increase in breast cancer risk was observed in carriers of the GHRL rs171407-G allele (odds ratio: 1.2; 95% confidence interval: 1.0-1.4; P = 0.02). The GHRL single-nucleotide polymorphism rs375577 was associated with a 5% increase in IGF-I levels (P = 0.01). A number of GHRL and GHSR polymorphisms were associated with body mass index (BMI) and height (P between GHRL variations are associated with BMI. Furthermore, we have observed evidence for association of GHRL polymorphisms with circulating IGF-I levels and with breast cancer risk. These associations, however, might also be due to chance findings and further large studies are needed to confirm our results.

  3. Eco RV RFLP at the insulin-like growth factor I (IGF I) locus on chromosome 12

    Energy Technology Data Exchange (ETDEWEB)

    Schneid, H; Noguiez, P; Girard, F; Binoux, M; Le Bouc, Y [INSERM U 142, Paris (France)

    1988-09-26

    The human liver IFG I cDNA insert from the {lambda}TG03 (1) was subcloned in PGEM4 (pTG 3906). The 660 bp Eco RI-Bam HI fragment containing the 5{prime} untranslated, the coding and the 3{prime} untranslated region of the IGF IA gene (exons 1, 2, 3 and 5) was used. Eco RV digestion of genomic DNA and hybridization with the IGF I probe reveals invariant fragments of 20; 8, 7 and 5 kb and polymorphic fragments of 13 kb (allele 1) and 11, 5 kb (allele 2). The frequency of alleles was studied in 51 unrelated European Caucasians. Co-dominant segregation was observed in 2 European families (9 individuals). Hind III and Pvu II digestions show previous described RFLP. Allelic frequencies however were: Hind III (5, 2 kb allele = 0, 14 and 4, 9 kb allele = 0, 86) and Pvu II (5 kb allele = 0, 14 and 4, 7 kb allele = 0, 86). Hind III and Pvu II RFLPs are linked. Among the DNA of the 14 individuals, where Eco RV RFLP was found, only one exhibited Hind III and Pvu II RFLPs.

  4. CARTILAGE CONSTRUCTS ENGINEERED FROM CHONDROCYTES OVEREXPRESSING IGF-I IMPROVE THE REPAIR OF OSTEOCHONDRAL DEFECTS IN A RABBIT MODEL

    Science.gov (United States)

    Madry, Henning; Kaul, Gunter; Zurakowski, David; Vunjak-Novakovic, Gordana; Cucchiarini, Magali

    2015-01-01

    Tissue engineering combined with gene therapy is a promising approach for promoting articular cartilage repair. Here, we tested the hypothesis that engineered cartilage with chondrocytes over expressing a human insulin-like growth factor I (IGF-I) gene can enhance the repair of osteochondral defects, in a manner dependent on the duration of cultivation. Genetically modified chondrocytes were cultured on biodegradable polyglycolic acid scaffolds in dynamic flow rotating bioreactors for either 10 or 28 d. The resulting cartilaginous constructs were implanted into osteochondral defects in rabbit knee joints. After 28 weeks of in vivo implantation, immunoreactivity to ß-gal was detectable in the repair tissue of defects that received lacZ constructs. Engineered cartilaginous constructs based on IGF-I-over expressing chondrocytes markedly improved osteochondral repair compared with control (lacZ) constructs. Moreover, IGF-I constructs cultivated for 28 d in vitro significantly promoted osteochondral repair vis-à-vis similar constructs cultivated for 10 d, leading to significantly decreased osteoarthritic changes in the cartilage adjacent to the defects. Hence, the combination of spatially defined overexpression of human IGF-I within a tissue-engineered construct and prolonged bioreactor cultivation resulted in most enhanced articular cartilage repair and reduction of osteoarthritic changes in the cartilage adjacent to the defect. Such genetically enhanced tissue engineering provides a versatile tool to evaluate potential therapeutic genes in vivo and to improve our comprehension of the development of the repair tissue within articular cartilage defects. Insights gained with additional exploration using this model may lead to more effective treatment options for acute cartilage defects. PMID:23588785

  5. Cartilage constructs engineered from chondrocytes overexpressing IGF-I improve the repair of osteochondral defects in a rabbit model

    Directory of Open Access Journals (Sweden)

    H Madry

    2013-04-01

    Full Text Available Tissue engineering combined with gene therapy is a promising approach for promoting articular cartilage repair. Here, we tested the hypothesis that engineered cartilage with chondrocytes overexpressing a human insulin-like growth factor I (IGF-I gene can enhance the repair of osteochondral defects, in a manner dependent on the duration of cultivation. Genetically modified chondrocytes were cultured on biodegradable polyglycolic acid scaffolds in dynamic flow rotating bioreactors for either 10 or 28 d. The resulting cartilaginous constructs were implanted into osteochondral defects in rabbit knee joints. After 28 weeks of in vivo implantation, immunoreactivity to ß-gal was detectable in the repair tissue of defects that received lacZ constructs. Engineered cartilaginous constructs based on IGF-I-overexpressing chondrocytes markedly improved osteochondral repair compared with control (lacZ constructs. Moreover, IGF-I constructs cultivated for 28 d in vitro significantly promoted osteochondral repair vis-à-vis similar constructs cultivated for 10 d, leading to significantly decreased osteoarthritic changes in the cartilage adjacent to the defects. Hence, the combination of spatially defined overexpression of human IGF-I within a tissue-engineered construct and prolonged bioreactor cultivation resulted in most enhanced articular cartilage repair and reduction of osteoarthritic changes in the cartilage adjacent to the defect. Such genetically enhanced tissue engineering provides a versatile tool to evaluate potential therapeutic genes in vivo and to improve our comprehension of the development of the repair tissue within articular cartilage defects. Insights gained with additional exploration using this model may lead to more effective treatment options for acute cartilage defects.

  6. Myofilament Calcium Sensitivity: Mechanistic Insight into TnI Ser-23/24 and Ser-150 Phosphorylation Integration

    Directory of Open Access Journals (Sweden)

    Hussam E Salhi

    2016-12-01

    Full Text Available Troponin I (TnI is a major regulator of cardiac muscle contraction and relaxation. During physiological and pathological stress, TnI is differentially phosphorylated at multiple residues through different signaling pathways to match cardiac function to demand. The combination of these TnI phosphorylations can exhibit an expected or unexpected functional integration, whereby the function of two phosphorylations are different than that predicted from the combined function of each individual phosphorylation alone. We have shown that TnI Ser-23/24 and Ser-150 phosphorylation exhibit functional integration and are simultaneously increased in response to cardiac stress. In the current study, we investigated the functional integration of TnI Ser-23/24 and Ser-150 to alter cardiac contraction. We hypothesized that Ser-23/24 and Ser-150 phosphorylation each utilize distinct molecular mechanisms to alter the TnI binding affinity within the thin filament. Mathematical modeling predicts that Ser-23/24 and Ser-150 phosphorylation affect different TnI affinities within the thin filament to distinctly alter the Ca2+-binding properties of troponin. Protein binding experiments validate this assertion by demonstrating pseudo-phosphorylated Ser-150 decreases the affinity of isolated TnI for actin, whereas Ser-23/24 pseudo-phosphorylation is not different from unphosphorylated. Thus, our data supports that TnI Ser-23/24 affects TnI-TnC binding, while Ser-150 phosphorylation alters TnI-actin binding. By measuring force development in troponin-exchanged skinned myocytes, we demonstrate that the Ca2+ sensitivity of force is directly related to the amount of phosphate present on TnI. Furthermore, we demonstrate that Ser-150 pseudo-phosphorylation blunts Ser-23/24-mediated decreased Ca2+-sensitive force development whether on the same or different TnI molecule. Therefore, TnI phosphorylations can integrate across troponins along the myofilament. These data demonstrate

  7. Insulin stimulates the tyrosine phosphorylation of a Mr = 160,000 glycoprotein in adipocyte plasma membranes

    International Nuclear Information System (INIS)

    Yu, K.T.; Khalaf, N.; Czech, M.P.

    1986-01-01

    In an attempt to identify putative substrates for the insulin receptor kinase, adipocyte plasma membranes were incubated with [γ- 32 P]ATP in the presence and absence of insulin. Insulin stimulates the tyrosine phosphorylation of its receptor β subunit but does not detectably alter the phosphorylation of other membrane proteins. In contrast, when plasma membranes from insulin-treated adipocytes are phosphorylated, the 32 P-labeling of a Mr=160,000 species (p160) and insulin receptor β subunit are markedly increased when compared to controls. p160 exhibits a rapid response (max. at 1 min) and high sensitivity (ED 50 = 2 x 10 -10 M) to insulin. The stimulatory effect of insulin on the phosphorylation of p160 is rapidly reversed following the addition of anti-insulin serum. Cold chase experiments indicate that insulin promotes the phosphorylation of p160 rather than inhibiting its dephosphorylation. p160 is a glycoprotein as evidenced by its adsorption to immobilized lectins and does not represent the insulin receptor precursor. The action of insulin on p160 tyrosine phosphorylation is mimicked by concanavalin A but not by EGF and other insulin-like agents such as hydrogen peroxide and vanadate. These results suggest that p160 tyrosine phosphorylation is an insulin receptor-mediated event and may participate in signalling by the insulin receptor

  8. IGF-1R mRNA expression is increased in obese children.

    Science.gov (United States)

    Ricco, Rafaela Cristina; Ricco, Rubens Garcia; Queluz, Mariangela Carletti; de Paula, Mariana Teresa Sarti; Atique, Patricia Volpon; Custódio, Rodrigo José; Tourinho Filho, Hugo; Del Roio Liberatori, Raphael; Martinelli, Carlos Eduardo

    2018-04-01

    Obese children are often taller than age-matched subjects. Reports on GH and IGF-I levels in obese individuals are controversial, with normal and reduced GH-IGF-I levels having been reported in this group of patients. Thus, the aim of this study was to analyse insulin-like growth factor type 1 receptor (IGF-IR) mRNA expression in obese children. Forty-seven pre-pubertal children were included in this study: 29 were obese and taller than their target height, and 18 were normal eutrophic controls. Fasting blood samples were collected for IGF-IR mRNA expression in isolated lymphocytes and serum IGF-I, ALS, IGFBP-3, and IGFBP-1 concentration analysis. Relative IGF-IR gene expression (2 -ΔΔCT ) was significantly (P=0.025) higher in obese children (median 1.87) than in controls (1.15). Fourteen of the 29 obese subjects showed 2 -ΔΔCT values greater than or equal to 2, while only 2 individuals in the control group showed values above 2 (P=0.01). Obese children showed significantly (P=0.01) higher IGF-I concentrations than the control group (237ng/ml and 144ng/ml, respectively). Among obese patients, 65.5% had IGF-I values above the 75 percentile of the control group (P=0.02). ALS concentration was significantly (P=0.04) higher in the obese group, while IGFBP-3 levels were similar in obese and control children. IGFBP-1 concentration was lower in obese children, while insulin levels and HOMA-IR index were higher than in controls. The higher IGF-IR mRNA expression observed in obese children, associated with the higher IGF-I and ALS and the lower IGFBP-1 levels, suggest that the higher stature observed in these children may be due to increased IGF-I bioactivity. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Liver-derived IGF-I contributes to GH-dependent increases in lean mass and bone mineral density in mice with comparable levels of circulating GH.

    Science.gov (United States)

    Nordstrom, Sarah M; Tran, Jennifer L; Sos, Brandon C; Wagner, Kay-Uwe; Weiss, Ethan J

    2011-07-01

    The relative contributions of circulating and locally produced IGF-I in growth remain controversial. The majority of circulating IGF-I is produced by the liver, and numerous mouse models have been developed to study the endocrine actions of IGF-I. A common drawback to these models is that the elimination of circulating IGF-I disrupts a negative feedback pathway, resulting in unregulated GH secretion. We generated a mouse with near total abrogation of circulating IGF-I by disrupting the GH signaling mediator, Janus kinase (JAK)2, in hepatocytes. We then crossed these mice, termed JAK2L, to GH-deficient little mice (Lit). Compound mutant (Lit-JAK2L) and control (Lit-Con) mice were treated with equal amounts of GH such that the only difference between the two groups was hepatic GH signaling. Both groups gained weight in response to GH but there was a reduction in the final weight of GH-treated Lit-JAK2L vs. Lit-Con mice. Similarly, lean mass increased in both groups, but there was a reduction in the final lean mass of Lit-JAK2L vs. Lit-Con mice. There was an equivalent increase in skeletal length in response to GH in Lit-Con and Lit-JAK2L mice. There was an increase in bone mineral density (BMD) in both groups, but Lit-JAK2L had lower BMD than Lit-Con mice. In addition, GH-mediated increases in spleen and kidney mass were absent in Lit-JAK2L mice. Taken together, hepatic GH-dependent production of IGF-I had a significant and nonredundant role in GH-mediated acquisition of lean mass, BMD, spleen mass, and kidney mass; however, skeletal length was dependent upon or compensated for by locally produced IGF-I.

  10. (igf1/igf1r) with milk production tr

    African Journals Online (AJOL)

    Gosia

    2016-06-15

    Jun 15, 2016 ... fragment length polymorphism (PCR-RFLP) (TaiI and MspI restriction enzymes) and amplification-created restriction site (ACRS) (SnaBI ... is the first association study based on polymorphisms of the primary genes encoding the IGF-1 system in a small herd of .... However, protein content was highest in milk ...

  11. Clonage de l'IGF-I et de son récepteur chez le turbot (Psetta maxima

    Directory of Open Access Journals (Sweden)

    ELIES G.

    1998-07-01

    Full Text Available Les IGF, leurs récepteurs et leurs protéines de liaison constituent une famille moléculaire qui joue un rôle essentiel dans la régulation de la croissance et du développement. Nous nous sommes intéressés à la caractérisation moléculaire de l'IGF-l et de son récepteur (IGF-1R chez le turbot (Psetta maxima, un poisson plat téléostéen. Par RT-PCR, nous avons clone un ADNc codant pour les quatre domaines de l'IGF-l mature. La protéine présente 70 à 96 % d'identité avec les autres IGF-I de vertébrés. Le clonage de la séquence codante entière du récepteur a nécessité la construction d'une banque d'ADNc d'embryons de turbots. Le récepteur est organisé en domaines dont la taille et les caractéristiques sont semblables à celles des autres récepteurs aux IGF de type 1 décrits chez les mammifères et le poulet. La région catalytique est particulièrement conservée. Dans certains domaines, notamment dans la région C-terminale du précurseur, quelques différences qui pourraient avoir une importance fonctionnelle sont cependant observées. Enfin, par RT-PCR, nous avons mis en évidence une régulation ontogénique du statut de polyadénylation des ARNm IGF-1R.

  12. Indications, limitations and pitfalls in the determination of human growth hormone, IGF-I and their binding proteins.

    Science.gov (United States)

    Laron, Zvi; Bidlingmaier, Martin; Strasburger, Christian Joseph

    2007-10-01

    Deviations from normal growth are a major part of Pediatric Endocrinology. The principal post-natal growth promoting hormones are pituitary growth hormone (GH) and insulin-like growth factor-I (IGF-I). The GH-IGF-I axis has many links and portals, the secrets of which have been disclosed in recent years by scientific advances (genetic and biochemical technologies). In this article, we describe the players in the GH axis, the auxological indications for performing GH evaluation tests, enumerate the most frequently used tests and discuss the laboratory tests which help to define the pathological entities along the GH axis. Emphasis is put on the limitations of methods used, lack of standards, norms and the possible errors in diagnosis and treatment indications that may evolve. As both hGH and IGF-I immunoassay measurements represent cornerstones in the diagnosis and monitoring of the different etiological entities presenting with short stature, clinicians must have an insight into the variability and limitations of these analytical techniques. Interpretation of biochemical results without proper reference data and without knowledge of the assay-inherent characteristics inevitably leads to misdiagnosis, unnecessary further testing and treatment and imposes a burden on the child, family and the health care system.

  13. Tobacco Smoke Exposure Impairs Brain Insulin/IGF Signaling: Potential Co-Factor Role in Neurodegeneration.

    Science.gov (United States)

    Deochand, Chetram; Tong, Ming; Agarwal, Amit R; Cadenas, Enrique; de la Monte, Suzanne M

    2016-01-01

    Human studies suggest tobacco smoking is a risk factor for cognitive impairment and neurodegeneration, including Alzheimer's disease (AD). However, experimental data linking tobacco smoke exposures to underlying mediators of neurodegeneration, including impairments in brain insulin and insulin-like growth factor (IGF) signaling in AD are lacking. This study tests the hypothesis that cigarette smoke (CS) exposures can impair brain insulin/IGF signaling and alter expression of AD-associated proteins. Adult male A/J mice were exposed to air for 8 weeks (A8), CS for 4 or 8 weeks (CS4, CS8), or CS8 followed by 2 weeks recovery (CS8+R). Gene expression was measured by qRT-PCR analysis and proteins were measured by multiplex bead-based or direct binding duplex ELISAs. CS exposure effects on insulin/IGF and insulin receptor substrate (IRS) proteins and phosphorylated proteins were striking compared with the mRNA. The main consequences of CS4 or CS8 exposures were to significantly reduce insulin R, IGF-1R, IRS-1, and tyrosine phosphorylated insulin R and IGF-1R proteins. Paradoxically, these effects were even greater in the CS8+R group. In addition, relative levels of S312-IRS-1, which inhibits downstream signaling, were increased in the CS4, CS8, and CS8+R groups. Correspondingly, CS and CS8+R exposures inhibited expression of proteins and phosphoproteins required for signaling through Akt, PRAS40, and/or p70S6K, increased AβPP-Aβ, and reduced ASPH protein, which is a target of insulin/IGF-1 signaling. Secondhand CS exposures caused molecular and biochemical abnormalities in brain that overlap with the findings in AD, and many of these effects were sustained or worsened despite short-term CS withdrawal.

  14. Clinical significance of measurment of changes of serum IGF-I, hs-CRP levels after treatment in patients with hyperthyroidism and hypothyroidism

    International Nuclear Information System (INIS)

    Zhu Conggang

    2009-01-01

    Objective: To explore the clinical significance of changes of serum IGF-I,hs-CRP levels after treatment in patients with hyperthyroidism and hypothyroidism. Methods: Serum IGF-I, hs-CRP(with RIA), and serum hs-CRP with immuno-turbidity methods levels were determined both before and after treatment in 36 cases of hyperthyroidism 30 cases of hypothyroidism as well as 35 controls. Results: Before treatment, the serum IGF-I levels in patients with hyperthyroidism were significantly higher and the levels in patients with hypothyroidism were significantly lower than those in controls (both P<0.01). After treatment for 3 months,the levels were much corrected, but still remained significantly different from those in controls (P<0.05). Before treatment serum hs-CRP levels in both groups of patients were significantly higher than those in controls (P<0.01), but after treatment,the levels were not much different from those in controls. Conclusion: Serum levels of IGF-I and hs-CRP were closely related to the disease process in patients with hyperthyroidism as well as in patients with hypothyroidism, and were much corrected after trentment.(authors)

  15. Growth hormone (GH) provocative retesting of 108 young adults with childhood-onset GH deficiency and the diagnostic value of insulin-like growth factor I (IGF-I) and IGF-binding protein-3

    DEFF Research Database (Denmark)

    Juul, A; Kastrup, K W; Pedersen, S A

    1997-01-01

    .e. 45% of patients treated with GH during childhood because of isolated GHD had a normal GH response when retested in adulthood. Multiple regression analysis revealed that peak GH levels were dependent on the degree of hypopituitarism, body mass index, and duration of disease. IGF-I levels were below -2...

  16. IGF-I during primiparous pregnancy and maternal risk of breast cancer

    OpenAIRE

    Chen, Tianhui; Lukanova, Annekatrin; Grankvist, Kjell; Zeleniuch-Jacquotte, Anne; Wulff, Marianne; Johansson, Robert; Schock, Helena; Lenner, Per; Hallmans, Goran; Wadell, Goran; Toniolo, Paolo; Lundin, Eva

    2009-01-01

    Abstract Previously, we reported that insulin-like growth factor (IGF)-I during early pregnancy is positively associated with maternal risk of breast cancer. To further explore this association, we designed a new study limited to women who donated a blood sample during their first pregnancy ending with childbirth. A case?control study was nested within the Northern Sweden Maternity Cohort in which repository since 1975, serum specimens remaining after early pregnancy screening for ...

  17. Fibroblast growth factor-mediated proliferation of central nervous system precursors depends on endogenous production of insulin-like growth factor I

    International Nuclear Information System (INIS)

    Drago, J.; Murphy, M.; Carroll, S.M.; Harvey, R.P.; Bartlett, P.F.

    1991-01-01

    Fibroblast growth factor stimulates proliferation and subsequent differentiation of precursor cells isolated from the neuroepithelium of embryonic day 10 mice in vitro. Here we show that fibroblast growth factor-induced proliferation is dependent on the presence of insulin-like growth factors (IGFs) and that IGF-I is endogenously produced by the neuroepithelial cells. Blocking of endogenous IGF-I activity with anti-IGF-I antibodies results in complete inhibition of fibroblast growth factor-mediated proliferation and in cell death. IGF-I alone acts as a survival agent. These observations correlate with the detection of transcripts for IGF-I and basic fibroblast growth factor in freshly isolated neuroepithelium and are consistent with an autocrine action of these factors in early brain development in vivo

  18. Cyclin dependent kinase 5 regulates endocytosis in nerve terminals via dynamin I phosphorylation

    International Nuclear Information System (INIS)

    Tan, T.C.; Hansra, G.; Calova, V.; Cousin, M.; Robinson, P.J.

    2002-01-01

    Full text: Synaptic vesicle endocytosis (SVE) in nerve terminals is essential for normal synaptic transmission and for memory retrieval. Dynamin I is a 96kDa nerve terminal phosphoprotein necessary for synaptic vesicle endocytosis in the nerve terminal. Dynamin I is dephosphorylated and rephosphorylated in a cyclical fashion with nerve terminal depolarisation and repolarisation. A number of kinases phosphorylate dynamin I in vitro including PKC, MAP kinase and cdc2. PKC phosphorylates dynamin in the proline rich domain on Ser 795 and is also thought to be the in vivo kinase for dynamin I. Another candidate is the neuron specific kinase cdk5, crucial for CNS development. The aim of this study is to identify the kinase which phosphorylates dynamin I in intact nerve terminals. Here we show that cyclin-dependent kinase 5 (cdk5) phosphorylates dynamin I in the proline-rich tail on Ser-774 or Ser-778. The phosphorylation of these sites but not Ser-795 also occurred in intact nerve terminals suggesting that cdk5 is the physiologically relevant enzyme for dynamin I. Synaptosomes prepared from rat brains (after cervical dislocations) and labelled with 32 Pi, were incubated with 100 M roscovitine (a selective inhibitor of cdks), 10 M Ro 31-8220 (a selective PKC inhibitor) and 100 M PD 98059 (a MEK kinase inhibitor). Dynamin rephosphorylation during repolarisation was reduced in synaptosomes treated with roscovitine and Ro 38-8220 but not in synaptosomes treated with PD 98059. Fluorimetric experiments on intact synaptosomes utilising FM-210 (a fluorescent dye) indicate that endocytosis was reduced in synaptosomes treated with 100 M roscovitine. Our results suggest that dynamin phosphorylation in intact nerve terminals may not be regulated by PKC or MAP kinase and that dynamin phosphorylation by cdk5 may regulate endocytosis. Copyright (2002) Australian Neuroscience Society

  19. Regulation of Xenopus laevis DNA topoisomerase I activity by phosphorylation in vitro

    International Nuclear Information System (INIS)

    Kaiserman, H.B.; Ingebritsen, T.S.; Benbow, R.M.

    1988-01-01

    DNA topoisomerase I has been purified to electrophoretic homogeneity from ovaries of the frog Xenopus laevis. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the most purified fraction revealed a single major band at 110 kDa and less abundant minor bands centered at 62 kDa. Incubation of the most purified fraction with immobilized calf intestinal alkaline phosphatase abolished all DNA topoisomerase enzymatic activity in a time-dependent reaction. Treatment of the dephosphorylated X. laevis DNA topoisomerase I with a X. laevis casein kinase type II activity and ATP restored DNA topoisomerase activity to a level higher than that observed in the most purified fraction. In vitro labeling experiments which employed the most purified DNA topoisomerase I fraction, [γ- 32 P]ATP, and the casein kinase type II enzyme showed that both the 110- and 62-kDa bands became phosphorylated in approximately molar proportions. Phosphoamino acid analysis showed that only serine residues became phosphorylated. Phosphorylation was accompanied by an increase in DNA topoisomerase activity in vitro. Dephosphorylation of DNA topoisomerase I appears to block formation of the initial enzyme-substrate complex on the basis of the failure of the dephosphorylated enzyme to nick DNA in the presence of camptothecin. The authors conclude that X. laevis DNA topoisomerase I is partially phosphorylated as isolated and that this phosphorylation is essential for expression of enzymatic activity in vitro. On the basis of the ability of the casein kinase type II activity to reactivate dephosphorylated DNA topoisomerase I, they speculate that this kinase may contribute to the physiological regulation of DNA topoisomerase I activity

  20. Serum insulin-like growth factor (IGF)-I and IGF binding protein-3 in relation to terminal duct lobular unit involution of the normal breast in Caucasian and African American women: The Susan G. Komen Tissue Bank.

    Science.gov (United States)

    Oh, Hannah; Pfeiffer, Ruth M; Falk, Roni T; Horne, Hisani N; Xiang, Jackie; Pollak, Michael; Brinton, Louise A; Storniolo, Anna Maria V; Sherman, Mark E; Gierach, Gretchen L; Figueroa, Jonine D

    2018-02-22

    Lesser degrees of terminal duct lobular unit (TDLU) involution, as reflected by higher numbers of TDLUs and acini/TDLU, are associated with elevated breast cancer risk. In rodent models, the insulin-like growth factor (IGF) system regulates involution of the mammary gland. We examined associations of circulating IGF measures with TDLU involution in normal breast tissues among women without precancerous lesions. Among 715 Caucasian and 283 African American (AA) women who donated normal breast tissue samples to the Komen Tissue Bank between 2009 and 2012 (75% premenopausal), serum concentrations of IGF-I and binding protein (IGFBP)-3 were quantified using enzyme-linked immunosorbent assay. Hematoxilyn and eosin-stained tissue sections were assessed for numbers of TDLUs ("TDLU count"). Zero-inflated Poisson regression models with a robust variance estimator were used to estimate relative risks (RRs) for association of IGF measures (tertiles) with TDLU count by race and menopausal status, adjusting for potential confounders. AA (vs. Caucasian) women had higher age-adjusted mean levels of serum IGF-I (137 vs. 131 ng/mL, p = 0.07) and lower levels of IGFBP-3 (4165 vs. 4684 ng/mL, p IGF-I:IGFBP-3 ratios were associated with higher TDLU count in Caucasian (RR T3vs.T1 =1.33, 95% CI = 1.02-1.75, p-trend = 0.04), but not in AA (RR T3vs.T1 =0.65, 95% CI = 0.42-1.00, p-trend = 0.05), women. Our data suggest a role of the IGF system, particularly IGFBP-3, in TDLU involution of the normal breast, a breast cancer risk factor, among Caucasian and AA women. © 2018 UICC.

  1. IGF and myostatin pathways are respectively induced during the earlier and the later stages of skeletal muscle hypertrophy induced by clenbuterol, a β₂-adrenergic agonist.

    Science.gov (United States)

    Abo, Tokuhisa; Iida, Ryo-Hei; Kaneko, Syuhei; Suga, Takeo; Yamada, Hiroyuki; Hamada, Yoshiki; Yamane, Akira

    2012-12-01

    Clenbuterol, a β₂-adrenergic agonist, increases the hypertrophy of skeletal muscle. Insulin-like growth factor (IGF) is reported to work as a potent positive regulator in the clenbuterol-induced hypertrophy of skeletal muscles. However, the precise regulatory mechanism for the hypertrophy of skeletal muscle induced by clenbuterol is unknown. Myostatin, a member of the TGFβ super family, is a negative regulator of muscle growth. The aim of the present study is to elucidate the function of myostatin and IGF in the hypertrophy of rat masseter muscle induced by clenbuterol. To investigate the function of myostatin and IGF in regulatory mechanism for the clenbuterol-induced hypertrophy of skeletal muscles, we analysed the expression of myostatin and phosphorylation levels of myostatin and IGF signaling components in the masseter muscle of rat to which clenbuterol was orally administered for 21 days. Hypertrophy of the rat masseter muscle was induced between 3 and 14 days of oral administration of clenbuterol and was terminated at 21 days. The expression of myostatin and the phosphorylation of smad2/3 were elevated at 21 days. The phosphorylation of IGF receptor 1 (IGFR1) and akt1 was elevated at 3 and 7 days. These results suggest that myostatin functions as a negative regulator in the later stages in the hypertrophy of rat masseter muscle induced by clenbuterol, whereas IGF works as a positive regulator in the earlier stages. Copyright © 2012 John Wiley & Sons, Ltd.

  2. Serum Levels Of Free And Total Insulin-Like Growth Factor (IGF)-1 And IGF Binding Protein-3 In Normal And Growth Hormone Deficient Children

    International Nuclear Information System (INIS)

    Shousha, M.A.; Soliman, S.E.T.; Hafez, M.H.

    2006-01-01

    Serum levels of total insulin-like growth factor-1 (IGF-1) and IGF-binding protein-3 (IGFBP-3) reflect the endogenous GH secretion in healthy children, which makes them good diagnostic markers for screening growth hormone deficiency (GHD) in short children, although some controversy still exists. Only a minor fraction of the total IGF-1 circulates in its free form, which is believed to be the biologically active form. Serum levels of free IGF-1, total IGF-I and IGFBP-3 were measured in 144 healthy children (72 boys and 72 girls, aged from 0 to 16 years) and in 12 pre-pubertal GH deficient (GHD) children to study the correlation between the age and free IGF-1, total IGF-1 and IGFBP-3 levels. In healthy subjects (both sexes), serum free IGF-1, total IGF-1 and IGFBP-3 levels were low in infancy, increasing during puberty and declining thereafter. Free IGF-1 in serum occupied about 0.97-1.45 % of the total IGF-1 values, and the ratios of free IGF-1 to total IGF-1 were significantly increased in the pubertal age groups than in the pre-pubertal age groups. Serum levels of free IGF-1 showed significant positive correlation with those of total IGF-I and IGFBP-3. Serum free IGF-1, total IGF-1 and IGFBP-3 levels in patients with GHD were decreased significantly with increasing the degree of hypopituitarism. These observations suggest that the increase in serum free IGF-1 level during puberty was caused by a dramatic increase in total IGF-1 rather than IGFBP-3. Also, high levels of these hormones may play an important role in pubertal growth spurt and may become a useful tool for diagnosing GHD and predicting growth response to long term GH therapy

  3. Serum levels of free and total insulin-link growth factor (IGF)-1 and (IGF) binding protein-3 in normal and growth hormone deficient children

    International Nuclear Information System (INIS)

    Shousha, M.A.; Soliman, S.E.T.; Hafez, H.M.

    2008-01-01

    Serum levels of total insulin-like growth factor- 1 (IGF-1) and IGF-binding protein-3 (IGFBP-3) reflect endogenous GH secretion in healthy children, which makes them good diagnostic markers for screening GH deficiency (GHD) in short children, although some controversy still exists. Only a minor fraction of the total IGF-1 circulates in its free form, which is believed to be the biologically active form. Serum levels of free IGF-1, total IGF-I and IGFBP-3 were measured in 144 healthy children (72 boys and 72 girls, aged from 0 to 16 years) and in 12 prepubertal GH. deficient (GHD) children to study correlation between the age and free IGF-1, total IGF-1 and IGFBP-3 levels. In healthy subjects (both sexes), serum free IGF-1, total IGF-1 and IGFBP-3 levels were low in infancy, increasing during puberty and declining thereafter. Free IGF-1 in serum occupied about 0.97. 1.45 % of the total IGF-1 values, and the ratios of free IGF-1 to total IGF-1 were significantly increased in the pubertal age groups than in the prepubertal age groups. Serum levels of free IGF-1 showed significant positive correlation with those of total IGF-I and IGFBP-3. Serum free IGF-1, total IGF-1 and IGFBP-3 levels in patients with GHD decreased significantly with increasing degree of hypopituitarism. These observations suggest that the increase in serum free IGF-1 level during puberty was caused by a dramatic increase in total IGF-1 rather than IGFBP-3. Also, high levels of these hormones may play an important role in pubertal growth spurt and may become a useful tool for diagnosing GHD and predicting growth response to long term GH therapy

  4. Plasma IGF-I, INSL3, testosterone, inhibin concentrations and scrotal circumferences surrounding puberty in Japanese Black beef bulls with normal and abnormal semen.

    Science.gov (United States)

    Weerakoon, W W P N; Sakase, M; Kawate, N; Hannan, M A; Kohama, N; Tamada, H

    2018-07-01

    The relationships between semen abnormalities and peripheral concentrations of testicular and metabolic hormones in beef bulls are unclear. Here we compared plasma insulin-like growth factor I (IGF-I), insulin-like peptide 3 (INSL3), testosterone, inhibin concentrations, and scrotal circumferences surrounding puberty in Japanese Black beef bulls (n = 66) with normal or abnormal semen. We collected blood samples and measured scrotal circumferences monthly from 4 to 24 months of age. Semen was collected weekly from 12 months until at least 18 months of age. Fresh semen was evaluated for semen volume, sperm motility, concentrations, and morphological defects. The normal fresh semen was frozen by a standard method and examined for post-thaw sperm motility and fertility. Bulls were classified as having either normal post-thaw semen (n = 45) or abnormal semen (n = 21, when at least one of the above test items was abnormal for 6 months). Abnormal semen was classified into abnormal fresh or low-fertility post-thaw which evaluated for rates of transferable embryos. The abnormal fresh was categorized as having sperm morphological defects, low motility, and morphological defects plus low motility. Scrotal circumferences were smaller for the abnormal-semen group vs. the normal-semen group at 20 and 24 months (p IGF-I, INSL3, and inhibin concentrations in the abnormal-semen group were lower than those of the normal-semen group (p IGF-I; 6, 9, 11-14, 17, and 20-21 months for INSL3; 5, 8-13, 16, 17, 19, and 20 months for inhibin). The plasma testosterone concentrations were lower in the abnormal-semen bulls vs. normal-semen bulls only at 22 months (p IGF-I and inhibin concentrations for low-fertility post-thaw semen (p IGF-I, INSL3, and inhibin surrounding puberty may be associated with semen aberration in beef bulls. Notably, the combined sperm abnormality of morphological defects and low motility in fresh semen could involve lowered INSL3, whereas the low

  5. Determining the normal range for IGF-I, IGFBP-3, and ALS: new reference data based on current internal standards.

    Science.gov (United States)

    Ertl, Diana-Alexandra; Gleiss, Andreas; Sagmeister, Susanne; Haeusler, Gabriele

    2014-09-01

    The measurement of insulin-like growth factors (IGF-I) and insulin-like growth factor-binding protein (IGFBP-3) often serves as first-line testing in children with growth disorders. The role of acid-labile subunit (ALS) as a screening parameter for homozygous or heterozygous mutations of the ALS gene still has to be determined. IGF-I, IGFBP-3, and ALS were measured in 252 samples from children and adolescents. Reference curves were fitted using generalized additive model for location, scale and shape (GAMLSS) models and SD-Scores were calculated. Bootstrap analysis was used to quantify the uncertainty of the estimated percentiles. Bland-Altman plots were used to investigate the discrepancy between our newly estimated standard deviation scores (SDS) and SDS calculated on the basis of previous reference data. We present reference data for enzyme-linked immunosorbent assay (ELISA) measurements based on recommended internal standard for IGF-I, IGFBP-3, and ALS suitable for calculation of SD-scores. The Bland-Altman plot shows a rough agreement between the previous SDS calculation and our new one only for SDS around 1; for SDS at -2, an average difference of 0.83 SD was noticed. Our IGF-I reference values for the interval of interest in diagnosing growth hormone deficiency (GHD) (prepubertal age) are solid as proved by bootstrap analysis. The difference in calculated SD scores by using data provided previously highlights the importance of using labor and method specific reference data.

  6. Hepatoprotection and neuroprotection induced by low doses of IGF-II in aging rats

    Directory of Open Access Journals (Sweden)

    Barhoum Rima

    2011-07-01

    Full Text Available Abstract Background GH and IGFs serum levels decline with age. Age-related changes appear to be associated to decreases in these anabolic hormones. We have previously demonstrated that IGF-I replacement therapy improves insulin resistance, lipid metabolism and reduces oxidative damage (in brain and liver in aging rats. Using the same experimental model, the aim of this work was to study whether the exogenous administration of IGF-II, at low doses, acts analogous to IGF-I in aging rats. Methods Three experimental groups were included in this study: young healthy controls (yCO, 17 weeks old; untreated old rats (O, 103 weeks old; and aging rats treated with IGF-II (O+IGF-II, 2 μg * 100 g body weight-1 * day-1 for 30 days. Analytical parameters were determined in serum by routine laboratory methods using an autoanalyzer (Cobas Mira; Roche Diagnostic System, Basel, Switzerland. Serum levels of hormones (testosterone, IGF-I and insulin were assessed by RIA. Serum Total Antioxidant Status was evaluated using a colorimetric assay. Mitochondrial membrane potential was evaluated using rhodamine 123 dye (adding different substrates to determine the different states. ATP synthesis in isolated mitochondria was determined by an enzymatic method. Results Compared with young controls, untreated old rats showed a reduction of IGF-I and testosterone levels with a decrease of serum total antioxidant status (TAS. IGF-II therapy improved serum antioxidant capability without modifying testosterone and IGF-I circulating concentrations. In addition, IGF-II treatment reduced oxidative damage in brain and liver, improving antioxidant enzyme activities and mitochondrial function. IGF-II was also able to reduce cholesterol and triglycerides levels increasing free fatty acids concentrations. Conclusions We demonstrate that low doses of IGF-II induce hepatoprotective, neuroprotective and metabolic effects, improving mitochondrial function, without affecting testosterone and

  7. Fibroin and sericin from Bombyx mori silk stimulate cell migration through upregulation and phosphorylation of c-Jun.

    Directory of Open Access Journals (Sweden)

    Celia Martínez-Mora

    Full Text Available Wound healing is a biological process directed to the restoration of tissue that has suffered an injury. An important phase of wound healing is the generation of a basal epithelium able to wholly replace the epidermis of the wound. A broad range of products derived from fibroin and sericin from Bombyx mori silk are used to stimulate wound healing. However, so far the molecular mechanism underlying this phenomenon has not been elucidated. The aim of this work was to determine the molecular basis underlying wound healing properties of silk proteins using a cell model. For this purpose, we assayed fibroin and sericin in a wound healing scratch assay using MDA-MB-231 and Mv1Lu cells. Both proteins stimulated cell migration. Furthermore, treatment with sericin and fibroin involved key factors of the wound healing process such as upregulation of c-Jun and c-Jun protein phosphorylation. Moreover, fibroin and sericin stimulated the phosphorylation of ERK 1/2 and JNK 1/2 kinases. All these experiments were done in the presence of specific inhibitors for some of the cell signalling pathways referred above. The obtained results revealed that MEK, JNK and PI3K pathways are involved in fibroin and sericin stimulated cells migration. Inhibition of these three kinases prevented c-Jun upregulation and phosphorylation by fibroin or sericin. Fibroin and sericin were tested in the human keratinocyte cell line, HaCaT, with similar results. Altogether, our results showed that fibroin and sericin initiate cell migration by activating the MEK, JNK and PI3K signalling pathways ending in c-Jun activation.

  8. Skeletal muscle hypertrophy and regeneration: interplay between the myogenic regulatory factors (MRFs) and insulin-like growth factors (IGFs) pathways.

    Science.gov (United States)

    Zanou, Nadège; Gailly, Philippe

    2013-11-01

    Adult skeletal muscle can regenerate in response to muscle damage. This ability is conferred by the presence of myogenic stem cells called satellite cells. In response to stimuli such as injury or exercise, these cells become activated and express myogenic regulatory factors (MRFs), i.e., transcription factors of the myogenic lineage including Myf5, MyoD, myogenin, and Mrf4 to proliferate and differentiate into myofibers. The MRF family of proteins controls the transcription of important muscle-specific proteins such as myosin heavy chain and muscle creatine kinase. Different growth factors are secreted during muscle repair among which insulin-like growth factors (IGFs) are the only ones that promote both muscle cell proliferation and differentiation and that play a key role in muscle regeneration and hypertrophy. Different isoforms of IGFs are expressed during muscle repair: IGF-IEa, IGF-IEb, or IGF-IEc (also known as mechano growth factor, MGF) and IGF-II. MGF is expressed first and is observed in satellite cells and in proliferating myoblasts whereas IGF-Ia and IGF-II expression occurs at the state of muscle fiber formation. Interestingly, several studies report the induction of MRFs in response to IGFs stimulation. Inversely, IGFs expression may also be regulated by MRFs. Various mechanisms are proposed to support these interactions. In this review, we describe the general process of muscle hypertrophy and regeneration and decipher the interactions between the two groups of factors involved in the process.

  9. Acute GH and IGF-I responses to short vs. long rest period between ...

    African Journals Online (AJOL)

    In order to examine the effects of different rest intervals between the sets on acute growth hormone (GH) and insulin-like growth factor-1 (IGF-I) responses, ten recreationally resistance trained men served as subjects (Mean ± SD, age=22 ± 2 years, body mass= 84 ± 8 kg). Subjects performed two heavy-resistance training ...

  10. IGF binding protein alterations on periplaque oligodendrocytes in multiple sclerosis : Implications for remyelination

    NARCIS (Netherlands)

    Wilczak, Nadine; Chesik, Daniel; Hoekstra, Dick; De Keyser, Jacques

    Why myelin repair greatly fails in multiple sclerosis (MS) is unclear. The insulin-like growth factor (IGF) system plays vital roles in oligodendrocyte development, survival, and myelin synthesis. We used immunohistochemistry to study IGF-I, IGF-I receptors and IGF binding proteins (IGFBPs) 1-6 on

  11. Sustained IGF-1 Secretion by Adipose-Derived Stem Cells Improves Infarcted Heart Function.

    Science.gov (United States)

    Bagno, Luiza L; Carvalho, Deivid; Mesquita, Fernanda; Louzada, Ruy A; Andrade, Bruno; Kasai-Brunswick, Taís H; Lago, Vivian M; Suhet, Grazielle; Cipitelli, Debora; Werneck-de-Castro, João Pedro; Campos-de-Carvalho, Antonio C

    2016-01-01

    The mechanism by which stem cell-based therapy improves heart function is still unknown, but paracrine mechanisms seem to be involved. Adipose-derived stem cells (ADSCs) secrete several factors, including insulin-like growth factor-1 (IGF-1), which may contribute to myocardial regeneration. Our aim was to investigate whether the overexpression of IGF-1 in ADSCs (IGF-1-ADSCs) improves treatment of chronically infarcted rat hearts. ADSCs were transduced with a lentiviral vector to induce IGF-1 overexpression. IGF-1-ADSCs transcribe100- to 200-fold more IGF-1 mRNA levels compared to nontransduced ADSCs. IGF-1 transduction did not alter ADSC immunophenotypic characteristics even under hypoxic conditions. However, IGF-1-ADSCs proliferate at higher rates and release greater amounts of growth factors such as IGF-1, vascular endothelial growth factor (VEGF), and hepatocyte growth factor (HGF) under normoxic and hypoxic conditions. Importantly, IGF-1 secreted by IGF-1-ADSCs is functional given that Akt-1 phosphorylation was remarkably induced in neonatal cardiomyocytes cocultured with IGF-1-ADSCs, and this increase was prevented with phosphatidylinositol 3-kinase (PI3K) inhibitor treatment. Next, we tested IGF-1-ADSCs in a rat myocardial infarction (MI) model. MI was performed by coronary ligation, and 4 weeks after MI, animals received intramyocardial injections of either ADSCs (n = 7), IGF-1-ADSCs (n = 7), or vehicle (n = 7) into the infarcted border zone. Left ventricular function was evaluated by echocardiography before and after 6 weeks of treatment, and left ventricular hemodynamics were assessed 7 weeks after cell injection. Notably, IGF-1-ADSCs improved left ventricular ejection fraction and cardiac contractility index, but did not reduce scar size when compared to the ADSC-treated group. In summary, transplantation of ADSCs transduced with IGF-1 is a superior therapeutic approach to treat MI compared to nontransduced ADSCs, suggesting that gene and cell

  12. The IGF-Axis and Diabetic Retinopathy Before and After Gastric Bypass Surgery

    DEFF Research Database (Denmark)

    Brynskov, Troels; Laugesen, Caroline Schmidt; Floyd, Andrea Karen

    2017-01-01

    at the two postoperative visits (p ≤ 0.001). Total IGF-I showed no significant changes. HbA1c, glucose, HOMA-IR and lipids improved after surgery. Two patients did not complete the 12-month visit. CONCLUSIONS: In obese T2D patients, bioactive IGF is a potential biomarker for DR and levels tended to increase....... We aimed to evaluate baseline imbalances in the circulating IGF-system and changes after LGB in patients with T2D. METHODS: Prospective ocular examinations and measurement of the IGF-axis before and 3 and 12 months after LGB. IGF-bioactivity was measured by cell-based IGF-I receptor (IGF-IR) kinase...

  13. IGF-1 Alleviates High Fat Diet-Induced Myocardial Contractile Dysfunction: Role of Insulin Signaling and Mitochondrial Function

    Science.gov (United States)

    Zhang, Yingmei; Yuan, Ming; Bradley, Katherine M.; Dong, Feng; Anversa, Piero; Ren, Jun

    2012-01-01

    Obesity is often associated with reduced plasma IGF-1 levels, oxidative stress, mitochondrial damage and cardiac dysfunction. This study was designed to evaluate the impact of IGF-1 on high fat diet-induced oxidative, myocardial, geometric and mitochondrial responses. FVB and cardiomyocyte-specific IGF-1 overexpression transgenic mice were fed a low (10%) or high fat (45%) diet to induce obesity. High fat diet feeding led to glucose intolerance, elevated plasma levels of leptin, interleukin-6, insulin and triglyceride as well as reduced circulating IGF-1 levels. Echocardiography revealed reduced fractional shortening, increased end systolic and diastolic diameter, increased wall thickness, and cardiac hypertrophy in high fat-fed FVB mice. High fat diet promoted ROS generation, apoptosis, protein and mitochondrial damage, reduced ATP content, cardiomyocyte cross-sectional area, contractile and intracellular Ca2+ dysregulation, including depressed peak shortening and maximal velocity of shortening/relengthening, prolonged duration of relengthening, and dampened intracellular Ca2+ rise and clearance. Western blot analysis revealed disrupted phosphorylation of insulin receptor, post-receptor signaling molecules IRS-1 (tyrosine/serine phosphorylation), Akt, GSK3β, Foxo3a, mTOR, as well as downregulated expression of mitochondrial proteins PPARγ coactivator 1α (PGC1α) and UCP-2. Intriguingly, IGF-1 mitigated high fat diet feeding-induced alterations in ROS, protein and mitochondrial damage, ATP content, apoptosis, myocardial contraction, intracellular Ca2+ handling and insulin signaling, but not whole body glucose intolerance and cardiac hypertrophy. Exogenous IGF-1 treatment also alleviated high fat diet-induced cardiac dysfunction. Our data revealed that IGF-1 alleviates high fat diet-induced cardiac dysfunction despite persistent cardiac remodeling, possibly due to preserved cell survival, mitochondrial function and insulin signaling. PMID:22275536

  14. IGF-1/IGF-1R/hsa-let-7c axis regulates the committed differentiation of stem cells from apical papilla

    Science.gov (United States)

    Ma, Shu; Liu, Genxia; Jin, Lin; Pang, Xiyao; Wang, Yanqiu; Wang, Zilu; Yu, Yan; Yu, Jinhua

    2016-01-01

    Insulin-like growth factor-1 (IGF-1) and its receptor IGF-1R play a paramount role in tooth/bone formation while hsa-let-7c actively participates in the osteogenic differentiation of mesenchymal stem cells. However, the interaction between IGF-1/IGF-1R and hsa-let-7c on the committed differentiation of stem cells from apical papilla (SCAPs) remains unclear. In this study, human SCAPs were isolated and treated with IGF-1 and hsa-let-7c over/low-expression viruses. The odonto/osteogenic differentiation of these stem cells and the involvement of mitogen-activated protein kinase (MAPK) pathway were subsequently investigated. Alizarin red staining showed that hsa-let-7c low-expression can significantly promote the mineralization of IGF-1 treated SCAPs, while hsa-let-7c over-expression can decrease the calcium deposition of IGF-1 treated SCAPs. Western blot assay and real-time reverse transcription polymerase chain reaction further demonstrated that the expression of odonto/osteogenic markers (ALP, RUNX2/RUNX2, OSX/OSX, OCN/OCN, COL-I/COL-I, DSPP/DSP, and DMP-1/DMP-1) in IGF-1 treated SCAPs were significantly upregulated in Let-7c-low group. On the contrary, hsa-let-7c over-expression could downregulate the expression of these odonto/osteogenic markers. Moreover, western blot assay showed that the JNK and p38 MAPK signaling pathways were activated in Let-7c-low SCAPs but inhibited in Let-7c-over SCAPs. Together, the IGF-1/IGF-1R/hsa-let-7c axis can control the odonto/osteogenic differentiation of IGF-1-treated SCAPs via the regulation of JNK and p38 MAPK signaling pathways. PMID:27833148

  15. Lower levels of circulating IGF-I in Type 1 diabetic women with frequent severe hypoglycaemia during pregnancy

    DEFF Research Database (Denmark)

    Ringholm Nielsen, L; Juul, A; Pedersen-Bjergaard, U

    2008-01-01

    Severe hypoglycaemia is a significant problem in pregnant women with Type 1 diabetes. We explored whether frequent severe hypoglycaemia during pregnancy in women with Type 1 diabetes is related to placental growth hormone (GH) and insulin-like growth factor I (IGF-I) levels....

  16. IGF-1 signaling mediated cell-specific skeletal mechano-transduction.

    Science.gov (United States)

    Tian, Faming; Wang, Yongmei; Bikle, Daniel D

    2018-02-01

    Mechanical loading preserves bone mass and stimulates bone formation, whereas skeletal unloading leads to bone loss. In addition to osteocytes, which are considered the primary sensor of mechanical load, osteoblasts, and bone specific mesenchymal stem cells also are involved. The skeletal response to mechanical signals is a complex process regulated by multiple signaling pathways including that of insulin-like growth factor-1 (IGF-1). Conditional osteocyte deletion of IGF-1 ablates the osteogenic response to mechanical loading. Similarly, osteocyte IGF-1 receptor (IGF-1R) expression is necessary for reloading-induced periosteal bone formation. Transgenic overexpression of IGF-1 in osteoblasts results in enhanced responsiveness to in vivo mechanical loading in mice, a response which is eliminated by osteoblastic conditional disruption of IGF-1 in vivo. Bone marrow derived stem cells (BMSC) from unloaded bone fail to respond to IGF-1 in vitro. IGF-1R is required for the transduction of a mechanical stimulus to downstream effectors, transduction which is lost when the IGF-1R is deleted. Although the molecular mechanisms are not yet fully elucidated, the IGF signaling pathway and its interactions with potentially interlinked signaling cascades involving integrins, the estrogen receptor, and wnt/β-catenin play an important role in regulating adaptive response of cancer bone cells to mechanical stimuli. In this review, we discuss recent advances investigating how IGF-1 and other interlinked molecules and signaling pathways regulate skeletal mechano-transduction involving different bone cells, providing an overview of the IGF-1 signaling mediated cell-specific response to mechanical stimuli. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:576-583, 2018. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  17. Association between insulin-like growth factor I (IGF-I microsatellite polymorphisms and important economic traits in pigs Associação entre polimorfismos no marcador microssatélite do gene do fator de crescimento semelhante à insulina I (IGF-I com características de interesse econômico em suínos

    Directory of Open Access Journals (Sweden)

    Danielle Assis de Faria

    2009-02-01

    Full Text Available This study investigated the association between IGF-I microsatellite marker in an F2 population (N=459 generated by mating of native boars to Brazilian commercial sows with performance, carcass cut, and meat quality traits. Association analyses were carried out using a statistical model that included genotype, sex, and group as fixed effects and sire as random effect. The IGF-I genotypes were significantly associated with different quantitative traits and these results corroborate with previous QTL analyses obtained for this chromosome region in swine. Additive and dominance effects, as well as a genotype-sex interaction, were estimated and discussed in the text. According to the results obtained, this marker is suitable for QTL search in the genotyped population.Investigou-se neste trabalho a associação entre o marcador microssatélite IGF-I em uma população F2 (N=459 gerada pelo acasalamento entre suínos nativos brasileiros e fêmeas comerciais com características de desempenho, cortes de carcaça e qualidade da carne. A análise de associação foi feita por meio de um modelo que incluiu genótipo, sexo e grupo como efeitos fixos e pais como efeito aleatório. Os genótipos do IGF-I apresentaram associação significativa com nove características quantitativas, resultados que corroboram análises prévias de QTL obtidas para essa região cromossômica em suínos. Efeitos aditivos de dominância, assim como a interação genótipo × sexo, foram estimados e estão descritos neste trabalho. De acordo com os resultados obtidos, este marcador será útil nas análises de QTL na população analisada.

  18. The Beneficial Impact of Antidepressant Drugs on Prenatal Stress-Evoked Malfunction of the Insulin-Like Growth Factor-1 (IGF-1) Protein Family in the Olfactory Bulbs of Adult Rats.

    Science.gov (United States)

    Trojan, Ewa; Głombik, Katarzyna; Ślusarczyk, Joanna; Budziszewska, Bogusława; Kubera, Marta; Roman, Adam; Lasoń, Władysław; Basta-Kaim, Agnieszka

    2016-02-01

    Insulin-like growth factor-1 (IGF-1) promotes the growth, differentiation, and survival of both neurons and glial cells, and it is believed to exert antidepressant-like activity. Thus, disturbances in the IGF-1 system could be responsible for the course of depression. To date, there have been no papers showing the impact of chronic antidepressant treatment on the IGF-1 network in the olfactory bulb (OB) in an animal model of depression. Prenatal stress was used as model of depression. Twenty-four 3-month-old male offspring of control and stressed mothers were subjected to behavioral testing (forced swim test). The mRNA expression of IGF-1 and IGF-1 receptor (IGF-1R) and the protein level of IGF-1 and its phosphorylation, as well as the concentrations of IGF-binding proteins (IGFBP-2, -4, -3, and -6), were measured in OBs before and after chronic imipramine, fluoxetine, or tianeptine administration. Adult rats exposed prenatally to stressful stimuli displayed not only depression-like behavior but also decreased IGF-1 expression, dysregulation in the IGFBP network, and diminished mRNA expression, as well as IGF-1R phosphorylation, in the OB. The administration of antidepressants normalized most of the changes in the IGF-1 system of the OB evoked by prenatal stress. These results suggested a beneficial effect of chronic antidepressant drug treatment in the alleviation of IGF-1 family malfunction in OBs in an animal model of depression.

  19. study on the serum levels of E2, IL-6 and IGF-I in patients with post-menopausal osteoporosis (PMO)

    International Nuclear Information System (INIS)

    Lv Kuan; Liu Chunyu; Lu Yingju

    2006-01-01

    Objective: To study the changes of serum levels of E 2 , IL-6, IGF-I in patients with post-menopausal osteoporosis (PMO). Methods: Serum levels of E 2 (with CLIA), IL-6, IGF-I, BGP (with RIA) were measured in the following subjects: (1) 32 patients with PMO (2) 32 post-menopausal women without PMO and (3) 30 pre-menopausal controls. Serum P, Ca and AKP levels were also determined. Results: As a whole, serum levels of IL -6 in postmenopausal women were higher than those in controls. Levels in subjects with PMO were significantly higher than those without PMO (P 2 and BMD index (r=-0. 587, - 0. 438 respectively, P 2 and BMD index (r=0.569, 0.433 respectively, P 2 levels will in someway promote the expression of IL-6 ( osteoclastic) and reduce the expression of IGF-I (osteoclastic), resulting in lessening of bone mass. HRT, despite of the controversy over cardio-vascalar safety, is beneficial for osteoporosis. (authors)

  20. Synthetic ligands of the elastin receptor induce elastogenesis in human dermal fibroblasts via activation of their IGF-1 receptors.

    Science.gov (United States)

    Qa'aty, Nour; Vincent, Matthew; Wang, Yanting; Wang, Andrew; Mitts, Thomas F; Hinek, Aleksander

    2015-12-01

    We have previously reported that a mixture of peptides obtained after chemical or enzymatic degradation of bovine elastin, induced new elastogenesis in human skin. Now, we investigated the elastogenic potential of synthetic peptides mimicking the elastin-derived, VGVAPG sequence, IGVAPG sequence that we found in the rice bran, and a similar peptide, VGVTAG that we identified in the IGF-1-binding protein-1 (IGFBP-1). We now demonstrate that treatment with each of these xGVxxG peptides (recognizable by the anti-elastin antibody), up-regulated the levels of elastin-encoding mRNA, tropoelastin protein, and the deposition of new elastic fibers in cultures of human dermal fibroblasts and in cultured explants of human skin. Importantly, we found that such induction of new elastogenesis may involve two parallel signaling pathways triggered after activation of IGF-1 receptor. In the first one, the xGVxxG peptides interact with the cell surface elastin receptor, thereby causing the downstream activation of the c-Src kinase and a consequent cross-activation of the adjacent IGF-1R, even in the absence of its principal ligand. In the second pathway their hydrophobic association with the N-terminal domain (VGVTAG) of the serum-derived IGFBP-1 induces conformational changes of this IGF-1 chaperone allowing for the release of its cargo and a consequent ligand-specific phosphorylation of IGF-1R. We present a novel, clinically relevant mechanism in which products of partial degradation of dermal elastin may stimulate production of new elastic fibers by dermal fibroblasts. Our findings particularly encourage the use of biologically safe synthetic xGVxxG peptides for regeneration of the injured or aged human skin. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  1. Chronic alterations in growth hormone/insulin-like growth factor-I signaling lead to changes in mouse tendon structure

    DEFF Research Database (Denmark)

    Nielsen, R H; Clausen, N M; Schjerling, P

    2014-01-01

    transgenic mice that expressed bovine GH (bGH) and had high circulating levels of GH and IGF-I, 2) dwarf mice with a disrupted GH receptor gene (GHR-/-) leading to GH resistance and low circulating IGF-I, and 3) a wild-type control group (CTRL). We measured the ultra-structure, collagen content and m......The growth hormone/insulin-like growth factor-I (GH/IGF-I) axis is an important stimulator of collagen synthesis in connective tissue, but the effect of chronically altered GH/IGF-I levels on connective tissue of the muscle-tendon unit is not known. We studied three groups of mice; 1) giant......-/- mice had significantly lower collagen fibril volume fraction in Achilles tendon, as well as decreased mRNA expression of IGF-I isoforms and collagen types I and III in muscle compared to CTRL. In contrast, the mRNA expression of IGF-I isoforms and collagens in bGH mice was generally high in both tendon...

  2. Complement component 1, q subcomponent binding protein (C1QBP) in lipid rafts mediates hepatic metastasis of pancreatic cancer by regulating IGF-1/IGF-1R signaling.

    Science.gov (United States)

    Shi, Haojun; Fang, Winston; Liu, Minda; Fu, Deliang

    2017-10-01

    Pancreatic cancer shows a remarkable predilection for hepatic metastasis. Complement component 1, q subcomponent binding protein (C1QBP) can mediate growth factor-induced cancer cell chemotaxis and distant metastasis by activation of receptor tyrosine kinases. Coincidentally, insulin-like growth factor-1 (IGF-1) derived from the liver and cancer cells itself has been recognized as a critical inducer of hepatic metastasis. However, the mechanism underlying IGF-1-dependent hepatic metastasis of pancreatic cancer, in which C1QBP may be involved, remains unknown. In the study, we demonstrated a significant association between C1QBP expression and hepatic metastasis in patients with pancreatic cancer. IGF-1 induced the translocation of C1QBP from cytoplasm to lipid rafts and further drove the formation of CD44 variant 6 (CD44v6)/C1QBP complex in pancreatic cancer cells. C1QBP interacting with CD44v6 in lipid rafts promoted phosphorylation of IGF-1R and thus activated downstream PI3K and MAPK signaling pathways which mediated metastatic potential of pancreatic cancer cells including proliferation, apoptosis, invasion, adhesion and energy metabolism. Furthermore, C1QBP knockdown suppressed hepatic metastasis of pancreatic cancer cells in nude mice. We therefore conclude that C1QBP in lipid rafts serves a key regulator of IGF-1/IGF-1R-induced hepatic metastasis from pancreatic cancer. Our findings about C1QBP in lipid rafts provide a novel strategy to block IGF-1/IGF-1R signaling in pancreatic cancer and a reliable premise for more efficient combined modality therapies. © 2017 UICC.

  3. Mechanical stimulation of cyclic tensile strain induces reduction of pluripotent related gene expressions via activation of Rho/ROCK and subsequent decreasing of AKT phosphorylation in human induced pluripotent stem cells

    International Nuclear Information System (INIS)

    Teramura, Takeshi; Takehara, Toshiyuki; Onodera, Yuta; Nakagawa, Koichi; Hamanishi, Chiaki; Fukuda, Kanji

    2012-01-01

    Highlights: ► Mechanical stimulation is an important factor for regulation of stem cell fate. ► Cyclic stretch to human induced pluripotent stem cells activated small GTPase Rho. ► Rho-kinase activation attenuated pluripotency via inhibition of AKT activation. ► This reaction could be reproduced only by transfection of dominant active Rho. ► Rho/ROCK are important molecules in mechanotransduction and control of stemness. -- Abstract: Mechanical stimulation has been shown to regulate the proliferation and differentiation of stem cells. However, the effects of the mechanical stress on the stemness or related molecular mechanisms have not been well determined. Pluripotent stem cells such as embryonic stem (ES) cells and induced pluripotent stem (iPS) cells are used as good materials for cell transplantation therapy and research of mammalian development, since they can self-renew infinitely and differentiate into various cell lineages. Here we demonstrated that the mechanical stimulation to human iPS cells altered alignment of actin fibers and expressions of the pluripotent related genes Nanog, POU5f1 and Sox2. In the mechanically stimulated iPS cells, small GTPase Rho was activated and interestingly, AKT phosphorylation was decreased. Inhibition of Rho-associated kinase ROCK recovered the AKT phosphorylation and the gene expressions. These results clearly suggested that the Rho/ROCK is a potent primary effector of mechanical stress in the pluripotent stem cells and it participates to pluripotency-related signaling cascades as an upper stream regulator.

  4. IGF-1-Involved Negative Feedback of NR2B NMDA Subunits Protects Cultured Hippocampal Neurons Against NMDA-Induced Excitotoxicity.

    Science.gov (United States)

    Li, Yun; Sun, Wei; Han, Song; Li, Jianing; Ding, Shu; Wang, Wei; Yin, Yanling

    2017-01-01

    Insulin-like growth factor 1 (IGF-1) is a multifunctional protein involved in neuronal polarity and axonal guidance. In our previous study, it was discovered that IGF-1 alleviated 50-μM NMDA-induced excitotoxicity against neuronal autophagy via depression of NR2B p-Ser1303 activation. However, it was found that NMDA at a higher dose did not cause neuronal autophagy. And, the performance of IGF-1 under severe excitotoxicity still needs to be clarified. In this study, we observed that IGF-1 can salvage the hippocampal neurons in an autophagy-independent manner after 150-μM NMDA exposure using thiazolyl blue tetrazolium bromide (MTT), lactate dehydrogenase (LDH), Western blot assay, and transmission electron microscopy. In addition, over-activation of post-synaptic NMDARs was found with the whole-cell patch clamp recording method. In order to explore whether there is a positive feedback way for post-synaptic NMDARs and the different pathway caused by 150 μM NMDA, the phosphorylation level of Fyn and the phosphorylation site of NR2B were investigated. It was observed that NR2B p-Tyr1472 was increased by the activation of Fyn after 150-μM NMDA exposure. When the neutralizing antibody against NR2B p-Ser1303 was added into the medium, both the activations of Fyn and NR2B p-Tyr1472 were blocked, suggesting NR2B p-Ser1303 may be the initial step of NMDA-induced excitotoxicity. In addition, since IGF-1 can block the initial step of NR2B activation, its effect is concluded to continue with the development of excitotoxicity. Overall, this study strongly indicates that the relationship between different phosphorylation sites of NR2B should be laid more emphasis on, which may be a vital target for the NR2B-involved excitotoxicity.

  5. Vasoinhibins Prevent Bradykinin-Stimulated Endothelial Cell Proliferation by Inactivating eNOS via Reduction of both Intracellular Ca2+ Levels and eNOS Phosphorylation at Ser1179

    Directory of Open Access Journals (Sweden)

    Carmen Clapp

    2011-07-01

    Full Text Available Vasoinhibins, a family of antiangiogenic peptides derived from prolactin proteolysis, inhibit the vascular effects of several proangiogenic factors, including bradykinin (BK. Here, we report that vasoinhibins block the BK-induced proliferation of bovine umbilical vein endothelial cells. This effect is mediated by the inactivation of endothelial nitric oxide synthase (eNOS, as the NO donor DETA-NONOate reverted vasoinhibin action. It is an experimentally proven fact that the elevation of intracellular Ca2+ levels ([Ca2+]i upon BK stimulation activates eNOS, and vasoinhibins blocked the BK-mediated activation of phospholipase C and the formation of inositol 1,4,5-triphosphate leading to a reduced release of Ca2+ from intracellular stores. The [Ca2+]i rise evoked by BK also involves the influx of extracellular Ca2+ via canonical transient receptor potential (TRPC channels. Vasoinhibins likely interfere with TRPC-mediated Ca2+ entry since La3+, which is an enhancer of TRPC4 and TRPC5 channel activity, prevented vasoinhibins from blocking the stimulation by BK of endothelial cell NO production and proliferation, and vasoinhibins reduced the BK-induced increase of TRPC5 mRNA expression. Finally, vasoinhibins prevented the BK-induced phosphorylation of eNOS at Ser1179, a post-translational modification that facilitates Ca2+-calmodulin activation of eNOS. Together, our data show that vasoinhibins, by lowering NO production through the inhibition of both [Ca2+]i mobilization and eNOS phosphorylation, prevent the BK-induced stimulation of endothelial cell proliferation. Thus, vasoinhibins help to regulate BK effects on angiogenesis and vascular homeostasis.

  6. GH and IGF-I levels are positively associated with musculotendinous collagen expression: Experiments in acromegalic and GHD patients

    DEFF Research Database (Denmark)

    Doessing, Simon; Holm, Lars; Heinemeier, Katja

    2010-01-01

    OBJECTIVE: Disproportionate growth of musculoskeletal tissue is a major cause of morbidity in both acromegalic (ACRO) and GH-deficient (GHD) patients. GH/IGF1 is likely to play an important role in the regulation of tendon and muscle collagen. We hypothesized that the local production of collagen...... is associated with the level of GH/IGF1.DESIGN AND METHODS: As primary outcomes, collagen mRNA expression and collagen protein fractional synthesis rate (FSR) were determined locally in skeletal muscle and tendon in nine ACRO and nine GHD patients. Moreover, muscle myofibrillar protein synthesis and tendon...... collagen morphology were determined.RESULTS AND CONCLUSIONS: Muscle collagen I and III mRNA expression was higher in ACRO patients versus GHD patients (PIGF1Ea and IGF1Ec...

  7. IGF-I deficiency, longevity and cancer protection of patients with Laron syndrome.

    Science.gov (United States)

    Laron, Zvi; Kauli, Rivka; Lapkina, Lena; Werner, Haim

    Laron syndrome (LS) is a unique model of congenital IGF-I deficiency. It is characterized by dwarfism and obesity, and is caused by deletion or mutations of the growth hormone receptor (GH-R) gene. It is hypothesized that LS is an old disease originating in Indonesia and that the mutated gene spread to South Asia, the Middle East, the Mediterranean region and South America. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. A highly phosphorylated subpopulation of insulin-like growth factor II/mannose 6-phosphate receptors is concentrated in a clathrin-enriched plasma membrane fraction

    International Nuclear Information System (INIS)

    Corvera, S.; Folander, K.; Clairmont, K.B.; Czech, M.P.

    1988-01-01

    Insulin-like growth factor II (IGF-II)/mannose 6-phosphate (Man-6-P) receptors immunoprecipitated from purified plasma membranes of 32 P-labeled rat adipocytes are markedly heterogenous in their phosphorylation state. Approximately 80% of the plasma membrane receptors are solubilized in 1% (vol/vol) Triton X-100 and are phosphorylated on serine residues at a stoichiometry of ∼ 0.1-0.2 mol of phosphate per mol of receptor. In contrast, 15-20% of the receptors are Triton X-100-insoluble and are phosphorylated on serine and threonine residues at ∼ 4 or 5 mol of phosphate per mol of receptor. This Triton X-100-insoluble membrane subfraction contains only 5% of the total plasma membrane protein and yet contains all of the clathrin heavy chain associated with plasma membrane. Based on the relative yields of protein in the detergent-insoluble material, IGF-II/Man-6-P receptors are concentrated ∼ 3-fold in this clathrin-enriched subfraction. Taken together, these results indicate that insulin decreases the phosphorylation state of a highly phosphorylated subpopulation of IGF-II/Man-6-P receptors on the plasma membrane. In addition, insulin action may prevent the concentration of these receptors in a clathrin-enriched membrane subfraction

  9. Effects of eccentric cycling exercise on IGF-I splice variant expression in the muscles of young and elderly people

    DEFF Research Database (Denmark)

    Hameed, M.; Toft, A.D.; Harridge, S.D.

    2008-01-01

    growth factor (MGF) were studied in response to 1 h of eccentric cycling exercise in young and old individuals. Subjects (nine young, aged 20-27 years and eight elderly, aged 67-75 years) completed an eccentric exercise protocol that consisted of 60 min of reverse pedal cycling. Workloads were chosen......Recovery from micro damage resulting from intensive exercise has been shown to take longer in older muscles. To investigate the factors that may contribute to muscle repair, we have studied the expression of two splice variants of the insulin-like growth factor-I (IGF-I) gene. IGF-IEa and mechano....... No difference was observed between the baseline levels of the two splice variants between the two subject groups. Eccentric cycling exercise resulted in a significant increase in the mean MGF mRNA in both young and old subjects but did not alter IGF-IEa mRNA levels in either age group. As reported previously...

  10. Membrane-associated insulin-like growth factor (IGF binding structures in placental cells

    Directory of Open Access Journals (Sweden)

    ROMANA MASNIKOSA

    2003-11-01

    Full Text Available The biological activities of IGF-I and –II are mediated mainly by the type 1 IGF receptor (IGF 1R and controlled by their interaction with soluble proteins, the IGF binding proteins (IGFBPs. Although there is a growing body of evidence that some IGFBPs may be cell surface-bound, published data concerning cell association of IGFBP-1 are scarce and none of them concern placental cells. The cell membranes used in this study were isolated from term human placentae. Detergent-solubilized membranes were shown to contain two types of IGF binding structures that were separated by gel filtration on a Sephadex G-100 column. Proteins in the first peak were eluted at V0 (Mr > 100 kD and they bound IGF-I with greater specificity and affinity than IGF-II and insulin. Most likely, they represented the IGF 1R. Small proteins (Mr ~ 45 kD were eluted with the membrane proteins in the second maximum. They were able to bind IGF-I and IGF-II, but not insulin. The identity of these proteins was shown to be IGFBP-1 on the basis of their reaction with specific anti-IGFBP-1 antibodies. To the best of our knowledge, the existence of IGFBP-1 associated with human placental cell membranes has not been reported in the literature before. Colocalisation of IGFBP-1 with IGF 1R in cell membranes could provide efficient modulation of IGF 1R receptor-ligand interactions.

  11. Growth hormone stimulates the collagen synthesis in human tendon and skeletal muscle without affecting myofibrillar protein synthesis

    DEFF Research Database (Denmark)

    Doessing, Simon; Heinemeier, Katja M; Holm, Lars

    2010-01-01

    young individuals. rhGH administration caused an increase in serum GH, serum IGF-I, and IGF-I mRNA expression in tendon and muscle. Tendon collagen I mRNA expression and tendon collagen protein synthesis increased by 3.9-fold and 1.3-fold, respectively (P ...RNA expression and muscle collagen protein synthesis increased by 2.3-fold and 5.8-fold, respectively (P protein synthesis was unaffected by elevation of GH and IGF-I. Moderate exercise did not enhance the effects of GH manipulation. Thus, increased GH availability stimulates...... matrix collagen synthesis in skeletal muscle and tendon, but without any effect upon myofibrillar protein synthesis. The results suggest that GH is more important in strengthening the matrix tissue than for muscle cell hypertrophy in adult human musculotendinous tissue....

  12. Role of IGF-1 in cortical plasticity and functional deficit induced by sensorimotor restriction.

    Science.gov (United States)

    Mysoet, Julien; Dupont, Erwan; Bastide, Bruno; Canu, Marie-Hélène

    2015-09-01

    In the adult rat, sensorimotor restriction by hindlimb unloading (HU) is known to induce impairments in motor behavior as well as a disorganization of somatosensory cortex (shrinkage of the cortical representation of the hindpaw, enlargement of the cutaneous receptive fields, decreased cutaneous sensibility threshold). Recently, our team has demonstrated that IGF-1 level was decreased in the somatosensory cortex of rats submitted to a 14-day period of HU. To determine whether IGF-1 is involved in these plastic mechanisms, a chronic cortical infusion of this substance was performed by means of osmotic minipump. When administered in control rats, IGF-1 affects the size of receptive fields and the cutaneous threshold, but has no effect on the somatotopic map. In addition, when injected during the whole HU period, IGF-1 is interestingly implied in cortical changes due to hypoactivity: the shrinkage of somatotopic representation of hindlimb is prevented, whereas the enlargement of receptive fields is reduced. IGF-1 has no effect on the increase in neuronal response to peripheral stimulation. We also explored the functional consequences of IGF-1 level restoration on tactile sensory discrimination. In HU rats, the percentage of paw withdrawal after a light tactile stimulation was decreased, whereas it was similar to control level in HU-IGF-1 rats. Taken together, the data clearly indicate that IGF-1 plays a key-role in cortical plastic mechanisms and in behavioral alterations induced by a decrease in sensorimotor activity. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Utility of circulating IGF-I as a biomarker for assessing body composition changes in men during periods of high physical activity superimposed upon energy and sleep restriction.

    Science.gov (United States)

    Nindl, Bradley C; Alemany, Joseph A; Kellogg, Mark D; Rood, Jennifer; Allison, Steven A; Young, Andrew J; Montain, Scott J

    2007-07-01

    Insulin-like growth factor (IGF)-I is a biomarker that may have greater utility than other conventional nutritional biomarkers in assessing nutritional, health, and fitness status. We hypothesized that the IGF-I system would directionally track a short-term energy deficit and would be more related to changes in body composition than other nutritional biomarkers. Thirty-five healthy men (24 +/- 0.3 yr) underwent 8 days of exercise and energy imbalance. Total and free IGF-I, IGF binding proteins-1, -2, and -3, the acid labile subunit, transferrin, ferritin, retinol binding protein, prealbumin, testosterone, triiodothyronine, thyroxine, and leptin responses were measured. Dual-energy X-ray absorptiometry assessed changes in body mass and composition. Repeated-measures ANOVA, correlation analysis, and receiver operator characteristic curves were used for statistical analyses (P losing >5% body mass. The IGF-I system is an important adjunct in the overall assessment of adaptation to stress imposed by high levels of physical activity superimposed on energy and sleep restriction and is more closely associated with losses in body mass and fat-free mass than other conventional nutritional biomarkers.

  14. Effects of Moderate Aerobic Exercise Combined with Caloric Restriction on Circulating Estrogens and IGF-I in Premenopausal Women

    National Research Council Canada - National Science Library

    Williams, Nancy

    2003-01-01

    The proposal entitled "Effects of moderate aerobic exercise combined with caloric restriction on circulating estrogens and IGF-I in premenopausal women will provide important scientific contributions...

  15. CCAAT/enhancer-binding protein delta activates insulin-like growth factor-I gene transcription in osteoblasts. Identification of a novel cyclic AMP signaling pathway in bone

    Science.gov (United States)

    Umayahara, Y.; Ji, C.; Centrella, M.; Rotwein, P.; McCarthy, T. L.

    1997-01-01

    Insulin-like growth factor-I (IGF-I) plays a key role in skeletal growth by stimulating bone cell replication and differentiation. We previously showed that prostaglandin E2 (PGE2) and other cAMP-activating agents enhanced IGF-I gene transcription in cultured primary rat osteoblasts through promoter 1, the major IGF-I promoter, and identified a short segment of the promoter, termed HS3D, that was essential for hormonal regulation of IGF-I gene expression. We now demonstrate that CCAAT/enhancer-binding protein (C/EBP) delta is a major component of a PGE2-stimulated DNA-protein complex involving HS3D and find that C/EBPdelta transactivates IGF-I promoter 1 through this site. Competition gel shift studies first indicated that a core C/EBP half-site (GCAAT) was required for binding of a labeled HS3D oligomer to osteoblast nuclear proteins. Southwestern blotting and UV-cross-linking studies showed that the HS3D probe recognized a approximately 35-kDa nuclear protein, and antibody supershift assays indicated that C/EBPdelta comprised most of the PGE2-activated gel-shifted complex. C/EBPdelta was detected by Western immunoblotting in osteoblast nuclear extracts after treatment of cells with PGE2. An HS3D oligonucleotide competed effectively with a high affinity C/EBP site from the rat albumin gene for binding to osteoblast nuclear proteins. Co-transfection of osteoblast cell cultures with a C/EBPdelta expression plasmid enhanced basal and PGE2-activated IGF-I promoter 1-luciferase activity but did not stimulate a reporter gene lacking an HS3D site. By contrast, an expression plasmid for the related protein, C/EBPbeta, did not alter basal IGF-I gene activity but did increase the response to PGE2. In osteoblasts and in COS-7 cells, C/EBPdelta, but not C/EBPbeta, transactivated a reporter gene containing four tandem copies of HS3D fused to a minimal promoter; neither transcription factor stimulated a gene with four copies of an HS3D mutant that was unable to bind osteoblast

  16. Chemoprotective effect of insulin-like growth factor I against acetaminophen-induced cell death in Chang liver cells via ERK1/2 activation

    International Nuclear Information System (INIS)

    Hwang, Hye-Jung; Kwon, Mi-Jin; Nam, Taek-Jeong

    2007-01-01

    The insulin-like growth factor (IGF) system and type-I IGF receptor (IGF-IR) signaling are involved in protecting against chemotherapeutic drug-induced cell death in human hepatoma cells. Acetaminophen (AAP) hepatotoxicity is the leading cause of liver failure, and the prevention of AAP-induced cell death has been the focus of many studies. We determined whether IGF-I could protect against AAP-induced cell death in Chang liver cells and investigated the protective mechanism. Based on the results of MTS assays, LDH release assays, Hoechst 33342 cell staining, and DNA fragmentation experiments, AAP induced cell death in a dose-dependent manner. According to Western blot analysis, treatment with AAP increased the level of poly(ADP-ribose) polymerase (PARP) fragments in cells compared with that in control cells; however, caspase-3, a critical signaling molecule in apoptosis, was not activated after AAP overdose. Moreover, combined treatment with AAP and IGF-I inhibited PARP cleavage, which was consistent with the ability of IGF-I to restore the level of glutathione (GSH) and cell viability in GSH and MTS assays, respectively. We investigated whether the protective effect of IGF-I against AAP cytotoxicity is related to the extracellular signal-related kinase ERK1/2, which is generally activated by mitogenic and proliferative stimuli such as growth factors. Compared with AAP treatment alone, IGF-I and AAP co-treatment increased ERK1/2 phosphorylation but inhibited PARP cleavage. Thus ERK1/2 activation is instrumental in the protective effect of IGF-I against AAP-induced cell death in Chang liver cells

  17. Gene expression profiling of preovulatory follicle in the buffalo cow: effects of increased IGF-I concentration on periovulatory events.

    Directory of Open Access Journals (Sweden)

    Jyotsna U Rao

    Full Text Available The preovulatory follicle in response to gonadotropin surge undergoes dramatic biochemical, and morphological changes orchestrated by expression changes in hundreds of genes. Employing well characterized bovine preovulatory follicle model, granulosa cells (GCs and follicle wall were collected from the preovulatory follicle before, 1, 10 and 22 h post peak LH surge. Microarray analysis performed on GCs revealed that 450 and 111 genes were differentially expressed at 1 and 22 h post peak LH surge, respectively. For validation, qPCR and immunocytochemistry analyses were carried out for some of the differentially expressed genes. Expression analysis of many of these genes showed distinct expression patterns in GCs and the follicle wall. To study molecular functions and genetic networks, microarray data was analyzed using Ingenuity Pathway Analysis which revealed majority of the differentially expressed genes to cluster within processes like steroidogenesis, cell survival and cell differentiation. In the ovarian follicle, IGF-I is established to be an important regulator of the above mentioned molecular functions. Thus, further experiments were conducted to verify the effects of increased intrafollicular IGF-I levels on the expression of genes associated with the above mentioned processes. For this purpose, buffalo cows were administered with exogenous bGH to transiently increase circulating and intrafollicular concentrations of IGF-I. The results indicated that increased intrafollicular concentrations of IGF-I caused changes in expression of genes associated with steroidogenesis (StAR, SRF and apoptosis (BCL-2, FKHR, PAWR. These results taken together suggest that onset of gonadotropin surge triggers activation of various biological pathways and that the effects of growth factors and peptides on gonadotropin actions could be examined during preovulatory follicle development.

  18. Desalted deep-sea water improves cognitive function in mice by increasing the production of insulin-like growth factor-I in the hippocampus.

    Science.gov (United States)

    Harada, Naoaki; Zhao, Juan; Kurihara, Hiroki; Nakagata, Naomi; Okajima, Kenji

    2011-08-01

    The stimulation of sensory neurons in the gastrointestinal (GI) tract improves cognitive function by increasing the hippocampal production of insulin-like growth factor-I (IGF-I) in mice. In the current study, we examined whether oral administration of desalted deep-sea water (DSW) increases the hippocampal production of IGF-I by stimulating sensory neurons in the GI tract, thereby improving cognitive function in mice. Desalted DSW increased calcitonin gene-related peptide (CGRP) release from dorsal root ganglion (DRG) neurons isolated from wild-type (WT) mice by activating transient receptor potential vanilloid 1. The plasma levels of IGF-I and tissue levels of CGRP, IGF-I, and IGF-I mRNA in the hippocampus were increased by oral administration of desalted DSW in WT mice. In these animals, nociceptive information originating from the GI tract was transmitted to the hippocampus via the spinothalamic pathway. Improvement of spatial learning was observed in WT mice after administration of desalted DSW. Distilled DSW showed results similar to those of desalted DSW in vitro and in vivo. None of the effects of desalted DSW in WT mice were observed after the administration of desalted DSW in CGRP-knockout (CGRP-/-) mice. No volatile compounds were detected in distilled DSW on GC-MS analysis. These observations suggest that desalted DSW may increase the hippocampal IGF-I production via sensory neuron stimulation in the Gl tract, thereby improving cognitive function in mice. Such effects of desalted DSW might not be dependent on the minerals but are dependent on the function of the water molecule itself. Copyright © 2011 Mosby, Inc. All rights reserved.

  19. Retardation of fetal dendritic development induced by gestational hyperglycemia is associated with brain insulin/IGF-I signals.

    Science.gov (United States)

    Jing, Yu-Hong; Song, Yan-Feng; Yao, Ya-Ming; Yin, Jie; Wang, De-Gui; Gao, Li-Ping

    2014-10-01

    Hyperglycemia is an essential risk factor for mothers and fetuses in gestational diabetes. Clinical observation has indicated that the offspring of mothers with diabetes shows impaired somatosensory function and IQ. However, only a few studies have explored the effects of hyperglycemia on fetal brain development. Neurodevelopment is susceptible to environmental conditions. Thus, this study aims to investigate the effects of maternal hyperglycemia on fetal brain development and to evaluate insulin and insulin-like growth factor-I (IGF-I) signals in fetal brain under hyperglycemia or controlled hyperglycemia. At day 1 of pregnancy, gestational rats were intraperitoneally injected with streptozocin (60 mg/kg). Some of the hyperglycemic gestational rats were injected with insulin (20 IU, two times a day) to control hyperglycemia; the others were injected with saline of equal volume. The gestational rats were sacrificed at days 14, 16, and 18 of embryo development. The dendritic spines of subplate cortex neurons in the fetal brain were detected by Golgi-Cox staining. The mRNA levels of insulin receptors (IRs) and IGF-IR in the fetal brain were measured using qRT-PCR. The protein levels of synaptophysin, IR, and IGF-IR in the fetal brain were detected by western blot. No significant difference in fetal brain formation was observed between the maternal hyperglycemic group and insulin-treated group. By contrast, obvious retardation of dendritic development in the fetus was observed in the maternal hyperglycemic group. Similarly, synaptophysin expression was lower in the fetus of the maternal hyperglycemic group than in that of the insulin-treated group. The mRNA and protein expression levels of IRs in the fetal brain were higher in the hyperglycemic group than in the insulin-treated group. By contrast, the levels of IGF-IR in the brain were lower in the fetus of the maternal hyperglycemic group than in that of the insulin-treated group. These results suggested that

  20. The limited screening value of insulin-like growth factor-I as a marker for alterations in body composition in very long-term adult survivors of childhood cancer.

    Science.gov (United States)

    Blijdorp, Karin; van den Heuvel-Eibrink, Marry; Pieters, Rob; Boot, Annemieke; Sluimer, Johanna; van der Lelij, Aart-Jan; Neggers, Sebastian

    2012-10-01

    The clinical relevance of low IGF-I levels, caused by cranial radiotherapy, in adult childhood cancer survivors has not been studied extensively. We evaluated whether IGF-I is a useful marker for altered body composition and growth hormone deficiency (GHD) in this group. We analyzed retrospective data from 610 adult childhood cancer survivors, retrieved from the late effects clinic. Median age at diagnosis was 6 years (interquartile range 3-11) and follow-up time was 18 years (13-24). We assessed IGF-I standard deviation scores (SDS), anthropometrical measures, growth hormone stimulation tests in patients with clinical signs of GHD, and measures of body composition (assessed by dual X-ray absorptiometry, Lunar Prodigy). In 58 cranially irradiated acute leukemia survivors (25 Gy (24-25)) and 56 locally irradiated brain tumor survivors (42 Gy (35-54)) we found significantly lower IGF-I SDS (P body mass index (P = 0.01), higher waist-hip ratio (WHR; P = 0.001), higher total fat percentage SDS (P body mass SDS (P body mass (r = 0.15, P = 0.01). In patients with low IGF-I levels, IGF-I did not significantly differ between subjects with and without GHD as determined by GH-stimulation testing (P = 0.39). This study shows that IGF-I has limited value as a marker for alterations in body composition in adult childhood cancer survivors. Copyright © 2011 Wiley Periodicals, Inc.

  1. Development and biological function of the female gonads and genitalia in IGF-I deficiency -- Laron syndrome as a model.

    Science.gov (United States)

    Laron, Zvi

    2006-01-01

    Laron syndrome (LS) or primary GH insensitivity is a unique human model to study the effects of congenital IGF-I deficiency. Within our cohort of 63 patients with LS, 15 female patients were regularly followed since birth or infancy, throughout puberty. We observed that they were short at birth, with small genitalia and gonads -- during puberty, developed delayed puberty but eventually reached between 16 and 19 1/2 years full sexual development. Reproduction is unaffected at a young adult age. It is concluded that IGF-I in concert with the sex hormones has a modulatory but not essential function on female sexual development and maturation.

  2. BDNF-TrkB Signaling Coupled to nPKCε and cPKCβI Modulate the Phosphorylation of the Exocytotic Protein Munc18-1 During Synaptic Activity at the Neuromuscular Junction

    Directory of Open Access Journals (Sweden)

    Anna Simó

    2018-06-01

    Full Text Available Munc18-1, a neuron-specific member of the Sec1/Munc18 family, is involved in neurotransmitter release by binding tightly to syntaxin. Munc18-1 is phosphorylated by PKC on Ser-306 and Ser-313 in vitro which reduces the amount of Munc18-1 able to bind syntaxin. We have previously identified that PKC is involved in neurotransmitter release when continuous electrical stimulation imposes a moderate activity on the NMJ and that muscle contraction through TrkB has an important impact on presynaptic PKC isoforms levels, specifically cPKCβI and nPKCε. Therefore, the present study was designed to understand how Munc18-1 phosphorylation is affected by (1 synaptic activity at the neuromuscular junction, (2 nPKCε and cPKCβI isoforms activity, (3 muscle contraction per se, and (4 the BDNF/TrkB signaling in a neuromuscular activity-dependent manner. We performed immunohistochemistry and confocal techniques to evidence the presynaptic location of Munc18-1 in the rat diaphragm muscle. To study synaptic activity, we stimulated the phrenic nerve (1 Hz, 30 min with or without contraction (abolished by μ-conotoxin GIIIB. Specific inhibitory reagents were used to block nPKCε and cPKCβI activity and to modulate the tropomyosin receptor kinase B (TrkB. Main results obtained from Western blot experiments showed that phosphorylation of Munc18-1 at Ser-313 increases in response to a signaling mechanism initiated by synaptic activity and directly mediated by nPKCε. Otherwise, cPKCβI and TrkB activities work together to prevent this synaptic activity–induced Munc18-1 phosphorylation by a negative regulation of cPKCβI over nPKCε. Therefore, a balance between the activities of these PKC isoforms could be a relevant cue in the regulation of the exocytotic apparatus. The results also demonstrate that muscle contraction prevents the synaptic activity–induced Munc18-1 phosphorylation through a mechanism that opposes the TrkB/cPKCβI/nPKCε signaling.

  3. BDNF-TrkB Signaling Coupled to nPKCε and cPKCβI Modulate the Phosphorylation of the Exocytotic Protein Munc18-1 During Synaptic Activity at the Neuromuscular Junction.

    Science.gov (United States)

    Simó, Anna; Just-Borràs, Laia; Cilleros-Mañé, Víctor; Hurtado, Erica; Nadal, Laura; Tomàs, Marta; Garcia, Neus; Lanuza, Maria A; Tomàs, Josep

    2018-01-01

    Munc18-1, a neuron-specific member of the Sec1/Munc18 family, is involved in neurotransmitter release by binding tightly to syntaxin. Munc18-1 is phosphorylated by PKC on Ser-306 and Ser-313 in vitro which reduces the amount of Munc18-1 able to bind syntaxin. We have previously identified that PKC is involved in neurotransmitter release when continuous electrical stimulation imposes a moderate activity on the NMJ and that muscle contraction through TrkB has an important impact on presynaptic PKC isoforms levels, specifically cPKCβI and nPKCε. Therefore, the present study was designed to understand how Munc18-1 phosphorylation is affected by (1) synaptic activity at the neuromuscular junction, (2) nPKCε and cPKCβI isoforms activity, (3) muscle contraction per se , and (4) the BDNF/TrkB signaling in a neuromuscular activity-dependent manner. We performed immunohistochemistry and confocal techniques to evidence the presynaptic location of Munc18-1 in the rat diaphragm muscle. To study synaptic activity, we stimulated the phrenic nerve (1 Hz, 30 min) with or without contraction (abolished by μ-conotoxin GIIIB). Specific inhibitory reagents were used to block nPKCε and cPKCβI activity and to modulate the tropomyosin receptor kinase B (TrkB). Main results obtained from Western blot experiments showed that phosphorylation of Munc18-1 at Ser-313 increases in response to a signaling mechanism initiated by synaptic activity and directly mediated by nPKCε. Otherwise, cPKCβI and TrkB activities work together to prevent this synaptic activity-induced Munc18-1 phosphorylation by a negative regulation of cPKCβI over nPKCε. Therefore, a balance between the activities of these PKC isoforms could be a relevant cue in the regulation of the exocytotic apparatus. The results also demonstrate that muscle contraction prevents the synaptic activity-induced Munc18-1 phosphorylation through a mechanism that opposes the TrkB/cPKCβI/nPKCε signaling.

  4. Mechanical stimulation of cyclic tensile strain induces reduction of pluripotent related gene expressions via activation of Rho/ROCK and subsequent decreasing of AKT phosphorylation in human induced pluripotent stem cells

    Energy Technology Data Exchange (ETDEWEB)

    Teramura, Takeshi, E-mail: teramura@med.kindai.ac.jp [Institute of Advanced Clinical Medicine, Kinki University, Faculty of Medicine, Osaka (Japan); Takehara, Toshiyuki; Onodera, Yuta [Institute of Advanced Clinical Medicine, Kinki University, Faculty of Medicine, Osaka (Japan); Nakagawa, Koichi; Hamanishi, Chiaki [Department of Orthopaedic Surgery, Kinki University, Faculty of Medicine, Osaka (Japan); Fukuda, Kanji [Institute of Advanced Clinical Medicine, Kinki University, Faculty of Medicine, Osaka (Japan); Department of Orthopaedic Surgery, Kinki University, Faculty of Medicine, Osaka (Japan)

    2012-01-13

    Highlights: Black-Right-Pointing-Pointer Mechanical stimulation is an important factor for regulation of stem cell fate. Black-Right-Pointing-Pointer Cyclic stretch to human induced pluripotent stem cells activated small GTPase Rho. Black-Right-Pointing-Pointer Rho-kinase activation attenuated pluripotency via inhibition of AKT activation. Black-Right-Pointing-Pointer This reaction could be reproduced only by transfection of dominant active Rho. Black-Right-Pointing-Pointer Rho/ROCK are important molecules in mechanotransduction and control of stemness. -- Abstract: Mechanical stimulation has been shown to regulate the proliferation and differentiation of stem cells. However, the effects of the mechanical stress on the stemness or related molecular mechanisms have not been well determined. Pluripotent stem cells such as embryonic stem (ES) cells and induced pluripotent stem (iPS) cells are used as good materials for cell transplantation therapy and research of mammalian development, since they can self-renew infinitely and differentiate into various cell lineages. Here we demonstrated that the mechanical stimulation to human iPS cells altered alignment of actin fibers and expressions of the pluripotent related genes Nanog, POU5f1 and Sox2. In the mechanically stimulated iPS cells, small GTPase Rho was activated and interestingly, AKT phosphorylation was decreased. Inhibition of Rho-associated kinase ROCK recovered the AKT phosphorylation and the gene expressions. These results clearly suggested that the Rho/ROCK is a potent primary effector of mechanical stress in the pluripotent stem cells and it participates to pluripotency-related signaling cascades as an upper stream regulator.

  5. Crosstalk between adiponectin and IGF-IR in breast cancer

    Directory of Open Access Journals (Sweden)

    Loredana eMauro

    2015-07-01

    Full Text Available Obesity is a chronic and multifactorial disorder that is reaching epidemic proportions. It is characterized by an enlarged mass of adipose tissue caused by a combination of size increase of preexisting adipocytes (hypertrophy and de novo adipocyte differentiation (hyperplasia. Obesity is related to many metabolic disorders like hypertension, type 2 diabetes, metabolic syndrome, cardiovascular disease, and it is associated with an increased risk of cancer development in different tissues including breast. Adipose tissue is now regarded as not just a storage reservoir for excess energy, but rather as an endocrine organ, secreting a large number of bioactive molecules called adipokines. Among these, adiponectin represents the most abundant adipose tissue-excreted protein, which exhibits insulin-sensitizing, anti-inflammatory and antiatherogenic properties. The serum concentrations of adiponectin are inversely correlated with body mass index. Recently, low levels of plasma adiponectin have been associated with an increased risk for obesity-related cancers and development of more aggressive phenotype, concomitantly with alterations in the bioavailability of Insulin-like Growth Factor-I (IGF-I and IGF-I Receptor (IGF-IR signaling pathways. In this review we discuss the cross-talk between adiponectin/AdipoR1 and IGF-I/IGF-IR in breast cancer.

  6. Regulation of insulin-like growth factor I receptors on vascular smooth muscle cells by growth factors and phorbol esters.

    Science.gov (United States)

    Ververis, J J; Ku, L; Delafontaine, P

    1993-06-01

    Insulin-like growth factor I (IGF I) is an important mitogen for vascular smooth muscle cells. To characterize regulation of vascular IGF I receptors, we performed radioligand displacement experiments using rat aortic smooth muscle cells (RASMs). Serum deprivation for 48 hours caused a 40% decrease in IGF I receptor number. Exposure of quiescent RASMs to platelet-derived growth factor (PDGF), fibroblast growth factor (FGF), or angiotensin II (Ang II) caused a 1.5-2.0-fold increase in IGF I receptors per cell. After FGF exposure, there was a marked increase in the mitogenic response to IGF I. IGF I downregulated its receptors in the presence of platelet-poor plasma. Stimulation of protein kinase C (PKC) by exposure of quiescent RASMs to phorbol 12-myristate 13-acetate caused a biphasic response in IGF I binding; there was a 42% decrease in receptor number at 45 minutes and a 238% increase at 24 hours. To determine the role of PKC in growth factor-induced regulation of IGF I receptors, we downregulated PKC by exposing RASMs to phorbol 12,13-dibutyrate (PDBu) for 48 hours. PDGF- and FGF- but not Ang II-mediated upregulation of IGF I receptors was completely inhibited in PDBu-treated cells. Thus, acute PKC activation by phorbol esters inhibits IGF I binding, whereas chronic PKC activation increases IGF I binding. PDGF and FGF but not Ang II regulate vascular IGF I receptors through a PKC-dependent pathway. These data provide new insights into the regulation of vascular smooth muscle cell IGF I receptors in vitro and are of potential importance in characterizing vascular proliferative responses in vivo.

  7. Cerebellar Insulin/IGF-1 signaling in diabetic rats: Effects of exercise training.

    Science.gov (United States)

    Borges, Mariana Eiras; Ribeiro, Alessandra Mussi; Pauli, José Rodrigo; Arantes, Luciana Mendonça; Luciano, Eliete; de Moura, Leandro Pereira; de Almeida Leme, José Alexandre Curiacos; Medeiros, Alessandra; Bertolini, Natália Oliveira; Sibuya, Clarice Yoshiko; Gomes, Ricardo José

    2017-02-03

    The Diabetes Mellitus (DM) is a chronic disease associated with loss of brain regions such as the cerebellum, increasing the risk of developing neurodegenerative diseases such as Parkinson's disease (PD). In the brain of diabetic and PD organisms the insulin/IGF-1 signaling is altered. Exercise training is an effective intervention for the prevention of neurodegerative diseases since it release neurotrophic factors and regulating insulin/IGF-1 signaling in the brain. This study aimed to evaluate the proteins involved in the insulin/IGF-1 pathway in the cerebellum of diabetic rats subjected to exercise training protocol. Wistar rats were distributed in four groups: sedentary control (SC), trained control (TC), sedentary diabetic (SD) and trained diabetic (TD). Diabetes was induced by Alloxan (ALX) (32mg/kgb.w.). The training program consisted in swimming 5days/week, 1h/day, during 6 weeks, supporting an overload corresponding to 90% of the anaerobic threshold. At the end, cerebellum was extracted to determinate the protein expression of GSK-3β, IRβ and IGF-1R and the phosphorylation of β-amyloid, Tau, ERK1+ERK2 by Western Blot analysis. All dependent variables were analyzed by one-way analysis of variance with significance level of 5%. Diabetes causes hyperglycemia in both diabetic groups; however, in TD, there was a reduction in hyperglycemia compared to SD. Diabetes increased Tau and β-amyloid phosphorylation in both SD and TD groups. Furthermore, aerobic exercise increased ERK1+ERK2 expression in TC. The data showed that in cerebellum of diabetic rats induced by alloxan there are some proteins expression like Parkinson cerebellum increased, and the exercise training was not able to modulate the expression of these proteins. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  8. Insulin-like growth factor II (IGF II) in human brain: regional distribution of IGF II and of higher molecular mass forms

    International Nuclear Information System (INIS)

    Haselbacher, G.K.; Schwab, M.E.; Pasi, A.; Humbel, R.E.

    1985-01-01

    Twenty-four distinct areas of human brain were analyzed for the presence of insulin-like growth factor (IGF). As reported for cerebrospinal fluid, only IGF II-like immunoreactivity, but no significant amounts of IGF I-like immunoreactivity, could be found. Upon gel permeation chromatography, two to five distinct size classes were separated on the basis of their immunoreactivity. Radioimmunoassays and a bioassay also gave results indistinguishable from those of serum IGF II. The highest amounts of IGF II-like immunoreactivity occur in the anterior pituitary. This is up to 100 times more than in most other brain regions analyzed. The higher molecular mass immunoreactive species were partially characterized. After immunoaffinity purification, the 38- and 26-kDa species are active in a bioassay. Specific IGF-binding protein activity could be shown after purification of the 38- and 26-kDa species on an IGF-affinity column. The 13-kDa species released significant amounts of 7.5-kDa material. The results are interpreted as evidence for the presence of IGF II synthesized locally in human brain

  9. Insulin treatment promotes tyrosine phosphorylation of PKR and inhibits polyIC induced PKR threonine phosphorylation.

    Science.gov (United States)

    Swetha, Medchalmi; Ramaiah, Kolluru V A

    2015-11-01

    Tyrosine phosphorylation of insulin receptor beta (IRβ) in insulin treated HepG2 cells is inversely correlated to ser(51) phosphorylation in the alpha-subunit of eukaryotic initiation factor 2 (eIF2α) that regulates protein synthesis. Insulin stimulates interaction between IRβ and PKR, double stranded RNA-dependent protein kinase, also known as EIF2AK2, and phosphorylation of tyrosine residues in PKR, as analyzed by immunoprecipitation and pull down assays using anti-IRβ and anti-phosphotyrosine antibodies, recombinant IRβ and immunopurified PKR. Further polyIC or synthetic double stranded RNA-induced threonine phosphorylation or activation of immunopurified and cellular PKR is suppressed in the presence of insulin treated purified IRβ and cell extracts. Acute, but not chronic, insulin treatment enhances tyrosine phosphorylation of IRβ, its interaction with PKR and tyrosine phosphorylation of PKR. In contrast, lipopolysaccharide that stimulates threonine phosphorylation of PKR and eIF2α phosphorylation and AG 1024, an inhibitor of the tyrosine kinase activity of IRβ, reduces PKR association with the receptor, IRβ in HepG2 cells. These findings therefore may suggest that tyrosine phosphorylated PKR plays a role in the regulation of insulin induced protein synthesis and in maintaining insulin sensitivity, whereas, suppression of polyIC-mediated threonine phosphorylation of PKR by insulin compromises its ability to fight against virus infection in host cells. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. Phosphorylated alpha(1 leads to 4) glucans as substrate for potato starch-branching enzyme I

    International Nuclear Information System (INIS)

    Vikso-Nielsen, A.; Blennow, A.; Nielsen, T.H.; Moller, B.L.

    1998-01-01

    The possible involvement of potato (Solanum tuberosum L.) starch-branching enzyme I (PSBE-I) in the in vivo synthesis of phosphorylated amylopectin was investigated in in vitro experiments with isolated PSBE-I using 33P-labeled phosphorylated and 3H end-labeled nonphosphorylated alpha(1 leads to 4) glucans as the substrates. From these radiolabeled substrates PSBE-I was shown to catalyze the formation of dual-labeled (3H/33P) phosphorylated branched polysaccharides with an average degree of polymerization of 80 to 85. The relatively high molecular mass indicated that the product was the result of multiple chain-transfer reactions. The presence of alpha(1 leads to 6) branch points was documented by isoamylase treatment and anion-exchange chromatography. Although the initial steps of the in vivo mechanism responsible for phosphorylation of potato starch remains elusive, the present study demonstrates that the enzyme machinery available in potato has the ability to incorporate phosphorylated alpha(1 leads to 4) glucans into neutral polysaccharides in an interchain catalytic reaction. Potato mini tubers synthesized phosphorylated starch from exogenously supplied 33PO4(3-) and [U-14C]Glc at rates 4 times higher than those previously obtained using tubers from fully grown potato plants. This system was more reproducible compared with soil-grown tubers and was therefore used for preparation of 33P-labeled phosphorylated alpha(1 leads to 4) glucan chains

  11. Characterization of insulin-like growth factor I receptors in the median eminence of the brain and their modulation by food restriction

    International Nuclear Information System (INIS)

    Bohannon, N.J.; Corp, E.S.; Wilcox, B.J.; Figlewicz, D.P.; Dorsa, D.M.; Baskin, D.G.

    1988-01-01

    High affinity binding sites for 125I-labeled [Thr59]insulin-like growth factor I (IGF-I) were measured in rat median eminence by in vitro autoradiography with slide-mounted sections of frozen rat brain. Specific binding of 0.1 nM iodo-[Thr59]IGF-I to brain slices reached maximum by 12 h at 4 C and was unchanged at 24 h. Densitometry by computer digital image analysis of autoradiographic images indicated that specific binding of iodo-[Thr59]IGF-I to the median eminence was reversible. The specificity of binding was evaluated with competition of iodo-[Thr59]IGF-I with unlabeled [Thr59]IGF-I, rat IGF-II (multiplication-stimulating activity), and porcine insulin. All were recognized by the binding site, but the rank order of potency was [Thr59]IGF-I greater than IGF-II greater than insulin. Somatostatin was completely ineffective. Further, an antibody against the rat IGF-II receptor did not block binding of iodo-[Thr59]IGF-I to the median eminence. Fourteen days of food restriction (75% of food intake of controls) resulted in significant weight loss and reduction of plasma immunoreactive IGF-I in six food-restricted rats (0.9 +/- 0.1 U/ml) compared with values in six controls (2.6 +/- 0.5 U/ml; P less than 0.001). Binding of 125I-labeled [Thr59]IGF-I in the median eminence was significantly increased in the food-restricted rats, primarily due to an increase in the concentration of iodo-[Thr59]IGF-I-binding sites in the median eminence; the affinity (Kd) of binding was unchanged. The results indicate that the median eminence has type I IGF-I receptors, which become more numerous under metabolic conditions associated with decreased caloric intake and lowered plasma IGF-I levels

  12. Possible effects of insulin-like growth factor-I, IGF-binding protein-3 and IGF-1/IGFBP-3 molar ratio on mammographic density: a cross-sectional study.

    Science.gov (United States)

    Meggiorini, M L; Cipolla, V; Borgoni, G; Nofroni, I; Pala, A; de Felice, C

    2012-01-01

    The purpose of this study was to examine the possible effects of IGF-1, IGFBP-3 and IGF-1/IGFBP-3 molar ratio on mammographic density and assess whether this relationship was similar in subgroups of pre- and postmenopausal women. A group of 341 Italian women of childbearing age or naturally postmenopausal who had performed mammographic examination at the section of radiology of our department a maximum three months prior to recruitment were enrolled. A blood sample was drawn for determination of IGF-1, IGFBP-3 levels and IGF-1/IGFBP-3 molar ratio was calculated. On the basis of recent mammograms the women were divided into two groups: dense breast (DB) and non-dense breast (NDB). To assess the association between mammographic density and IGF-1, IGFBP-3 and Molar ratio Student's t-test was employed before and after stratified by menopausal status. The analysis of the relationship between mammographic density and plasma levels of IGF-1, IGFBP-3 and IGF-1/IGFBP-3 molar ratio showed that IGF-1 levels and molar ratio varied in the two groups resulting in higher mean values in the DB group whereas IGFBP-3 showed similar values in both groups (DB and NDB). After stratification of the study population by menopausal status, no association was found. Our study provides strong evidence of a crude association between breast density, and plasma levels of IGF-1 and molar ratio. IGF-1 and molar ratio might increase mammographic density and thus the risk of developing breast cancer.

  13. Protein phosphorylation in isolated hepatocytes of septic and endotoxemic rats

    International Nuclear Information System (INIS)

    Deaciuc, I.V.; Spitzer, J.A.

    1989-01-01

    The purpose of this study was to investigate possible alterations induced by sepsis and endotoxicosis in the late phase of Ca2+-dependent signaling in rat liver. Hepatocytes isolated from septic or chronically endotoxin (ET)-treated rats were labeled with [32P]H3PO4 and stimulated with various agents. Proteins were resolved by one-dimensional polyacrylamide gel electrophoresis and autoradiographed. Vasopressin (VP)- and phenylephrine (PE)-induced responses were attenuated in both septic and ET-treated rats for cytosolic and membrane proteins compared with their respective controls. Glucagon and 12-O-myristate phorbol-13-acetate (TPA) affected only the phosphorylation of membrane proteins. Glucagon-induced changes in the phosphorylation of membrane proteins were affected by both sepsis and endotoxicosis, whereas TPA-stimulated phosphorylation was lowered only in endotoxicosis. Response to the Ca2+ ionophore A23187 was depressed in septic rats for cytosolic proteins. The phosphorylation of two cytosolic proteins, i.e., 93 and 61 kDa (previously identified as glycogen phosphorylase and pyruvate kinase, respectively), in response to VP, PE, and A23187 was severely impaired by endotoxicosis and sepsis. TPA did not affect the phosphorylation state of these two proteins. The results show that sepsis and endotoxicosis produce perturbations of the phosphorylation step in Ca2+ transmembrane signaling. Such changes can explain alterations of glycogenolysis and gluconeogenesis associated with sepsis and endotoxicosis

  14. Beta-hydroxy-beta-methylbutyrate (HMB) stimulates myogenic cell proliferation, differentiation and survival via the MAPK/ERK and PI3K/Akt pathways.

    Science.gov (United States)

    Kornasio, Reut; Riederer, Ingo; Butler-Browne, Gillian; Mouly, Vincent; Uni, Zehava; Halevy, Orna

    2009-05-01

    Beta-hydroxy-beta-methylbutyrate (HMB), a leucine catabolite, has been shown to prevent exercise-induced protein degradation and muscle damage. We hypothesized that HMB would directly regulate muscle-cell proliferation and differentiation and would attenuate apoptosis, the latter presumably underlying satellite-cell depletion during muscle degradation or atrophy. Adding various concentrations of HMB to serum-starved myoblasts induced cell proliferation and MyoD expression as well as the phosphorylation of MAPK/ERK. HMB induced differentiation-specific markers, increased IGF-I mRNA levels and accelerated cell fusion. Its inhibition of serum-starvation- or staurosporine-induced apoptosis was reflected by less apoptotic cells, reduced BAX expression and increased levels of Bcl-2 and Bcl-X. Annexin V staining and flow cytometry analysis showed reduced staurosporine-induced apoptosis in human myoblasts in response to HMB. HMB enhanced the association of the p85 subunit of PI3K with tyrosine-phosphorylated proteins. HMB elevated Akt phosphorylation on Thr308 and Ser473 and this was inhibited by Wortmannin, suggesting that HMB acts via Class I PI3K. Blocking of the PI3K/Akt pathway with specific inhibitors revealed its requirement in mediating the promotive effects of HMB on muscle cell differentiation and fusion. These direct effects of HMB on myoblast differentiation and survival resembling those of IGF-I, at least in culture, suggest its positive influence in preventing muscle wasting.

  15. Breast Cancer Risk in Relation to Serum IGF-I, IGFBP-3 and their Genetic Determinants: A Study Within the European Prospective Investigation into Cancer (EPIC)

    National Research Council Canada - National Science Library

    Kaaks, Rudolf

    2002-01-01

    Purpose and scope: we are conducting a large case-control study, nested within a prospective cohort, to estimate relative risks of breast cancer by levels of IGF-I and IGFBP-3, and to examine associations of IGF...

  16. Feed restriction and insulin-like growth factor-I (IGF-I) affect the oocyte maturation in matrinxã Brycon amazonicus.

    Science.gov (United States)

    Montrezor, Luís Henrique; Urbinati, Elisabeth Criscuolo

    2017-02-01

    The feeding and nutrition of breeders are crucial aspects in the reproductive process. During the maturation period, metabolic changes occur aiming at mobilizing energy for growth and follicular development. The involvement of IGF-1 in metabolic and reproductive events is important. The aim of this work was to evaluate if alternate feed restriction and re-feeding have permissive effects on in vitro actions of IGF-1 on oocytes development of matrinxã. In vivo experiments were performed during vitellogenesis period. Females (n = 60) were fed with a commercial feed (2% of biomass) and they were divided into two treatments: fish receiving food daily (control - fed), and fish submitted to cycles of 3 days of feed restriction and 2 days of re-feeding (no-fed group). For the in vitro experiments, oocytes (n = 20) were obtained from the ovaries removed at the end of the in vivo experiment and were divided into four groups: fed -IGF-1; fed +IGF-1; no-fed -IGF-1 and no-fed +IGF-1. Fish under restriction had lower body weights, decreased plasma glucose, increased triglycerides levels, and their final maturation and mature oocyte were reduced and the atresic ones were in higher number. Moreover, IGF-1, in vitro, increased the percentage of mature oocytes in fed females and decreased the atresic ones. In no-fed females, IGF-1 increased the final maturation and mature oocytes and reduced the atresic ones. This study demonstrates the importance of the feeding management of female breeders of matrinxã during the vitellogenesis period.

  17. Cyclic-glycine-proline accelerates mammary involution by promoting apoptosis and inhibiting IGF-1 function.

    Science.gov (United States)

    Singh-Mallah, Gagandeep; McMahon, Christopher D; Guan, Jian; Singh, Kuljeet

    2017-12-01

    In rodents, post-lactational involution of mammary glands is characterized by the loss of mammary epithelial cells via apoptosis, which is associated with a decline in the expression of insulin-like growth factor-1 (IGF-1). Overexpression of IGF-1 delays involution by inhibiting apoptosis of epithelial cells and preserving the remaining secretory alveoli. Cyclic-glycine-proline (cGP), a metabolite of IGF-1, normalizes IGF-1 function under pathological conditions by regulating the bioavailability of IGF-1. The present study investigated the effect of cGP on the physiological decline in IGF-1 function during post-lactational mammary involution. Rat dams were gavaged with either cGP (3 mg/kg) or saline once per day from post-natal d8-22. Before collecting tissue on post-natal d23, a pair of mammary glands were sealed on d20 (72 hr-engorgement, thus representative of late-involution) and d22 (24 hr-engorgement, thus representative of mid-involution), while the remaining glands were allowed to involute naturally (early-involution). During early-involution, cGP accelerated the loss of mammary cells through apoptosis, resulting in an earlier clearance of intact secretory alveoli compared with the control group. This coincided with an earlier up-regulation of the cell survival factors, Bcl-xl and IGF-1R, in the early-involution cGP glands compared with the control glands. During late-involution, cGP reduced the bioactivity of IGF-1, which was evident through decreased phosphorylation of IGF-1R in the regressed alveoli. Maternal administration of cGP did not alter milk production and composition during early-, peak-, or late-stage of lactation. These data show that cGP accelerates post-lactational involution by promoting apoptosis and the physiological decline in IGF-1 function. © 2017 Wiley Periodicals, Inc.

  18. Phosphorylation of dynamin I on Ser-795 by protein kinase C blocks its association with phospholipids

    DEFF Research Database (Denmark)

    Powell, K A; Valova, V A; Malladi, C S

    2000-01-01

    Dynamin I is phosphorylated in nerve terminals exclusively in the cytosolic compartment and in vitro by protein kinase C (PKC). Dephosphorylation is required for synaptic vesicle retrieval, suggesting that its phosphorylation affects its subcellular localization. An in vitro phospholipid binding ...... assay was established that prevents lipid vesiculation and dynamin lipid insertion into the lipid. Dynamin I bound the phospholipid in a concentration-dependent and saturable manner, with an apparent affinity of 230 +/- 51 nM. Optimal binding occurred with mixtures of phosphatidylserine...... the phosphorylation site in PKCalpha-phosphorylated dynamin I as a single site at Ser-795, located near a binding site for the SH3 domain of p85, the regulatory subunit of phosphatidylinositol 3-kinase. However, phosphorylation had no effect on dynamin binding to a bacterially expressed p85-SH3 domain. Thus...

  19. Differential roles of PKC isoforms (PKCs) in GnRH stimulation of MAPK phosphorylation in gonadotrope derived cells.

    Science.gov (United States)

    Mugami, Shany; Dobkin-Bekman, Masha; Rahamim-Ben Navi, Liat; Naor, Zvi

    2018-03-05

    The role of protein kinase C (PKC) isoforms (PKCs) in GnRH-stimulated MAPK [ERK1/2, JNK1/2 and p38) phosphorylation was examined in gonadotrope derived cells. GnRH induced a protracted activation of ERK1/2 and a slower and more transient activation of JNK1/2 and p38MAPK. Gonadotropes express conventional PKCα and PKCβII, novel PKCδ, PKCε and PKCθ, and atypical PKC-ι/λ. The use of green fluorescent protein (GFP)-PKCs constructs revealed that GnRH induced rapid translocation of PKCα and PKCβII to the plasma membrane, followed by their redistribution to the cytosol. PKCδ and PKCε localized to the cytoplasm and Golgi, followed by the rapid redistribution by GnRH of PKCδ to the perinuclear zone and of PKCε to the plasma membrane. The use of dominant negatives for PKCs and peptide inhibitors for the receptors for activated C kinase (RACKs) has revealed differential role for PKCα, PKCβII, PKCδ and PKCε in ERK1/2, JNK1/2 and p38MAPK phosphorylation in a ligand-and cell context-dependent manner. The paradoxical findings that PKCs activated by GnRH and PMA play a differential role in MAPKs phosphorylation may be explained by persistent vs. transient redistribution of selected PKCs or redistribution of a given PKC to the perinuclear zone vs. the plasma membrane. Thus, we have identified the PKCs involved in GnRH stimulated MAPKs phosphorylation in gonadotrope derived cells. Once activated, the MAPKs will mediate the transcription of the gonadotropin subunits and GnRH receptor genes. Copyright © 2017. Published by Elsevier B.V.

  20. Regulation of insulin-like growth factor I transcription by cyclic adenosine 3',5'-monophosphate (cAMP) in fetal rat bone cells through an element within exon 1: protein kinase A-dependent control without a consensus AMP response element

    Science.gov (United States)

    McCarthy, T. L.; Thomas, M. J.; Centrella, M.; Rotwein, P.

    1995-01-01

    Insulin-like growth factor I (IGF-I) is a locally synthesized anabolic growth factor for bone. IGF-I synthesis by primary fetal rat osteoblasts (Ob) is stimulated by agents that increase the intracellular cAMP concentration, including prostaglandin E2 (PGE2). Previous studies with Ob cultures demonstrated that PGE2 enhanced IGF-I transcription through selective use of IGF-I promoter 1, with little effect on IGF-I messenger RNA half-life. Transient transfection of Ob cultures with an array of promoter 1-luciferase reporter fusion constructs has now allowed localization of a potential cis-acting promoter element(s) responsible for cAMP-stimulated gene expression to the 5'-untranslated region (5'-UTR) of IGF-I exon 1, within a segment lacking a consensus cAMP response element. Our evidence derives from three principal observations: 1) a transfection construct containing only 122 nucleotides (nt) of promoter 1 and 328 nt of the 5'-UTR retained full PGE2-stimulated reporter expression; 2) maximal PGE2-driven reporter expression required the presence of nt 196 to 328 of exon 1 when tested within the context of IGF-I promoter 1; 3) cotransfection of IGF-I promoter-luciferase-reporter constructs with a plasmid encoding the alpha-isoform of the catalytic subunit of murine cAMP-dependent protein kinase (PKA) produced results comparable to those seen with PGE2 treatment, whereas cotransfection with a plasmid encoding a mutant regulatory subunit of PKA that cannot bind cAMP blocked PGE2-induced reporter expression. Deoxyribonuclease I footprinting of the 5'-UTR of exon 1 demonstrated protected sequences at HS3A, HS3B, and HS3D, three of six DNA-protein binding sites previously characterized with rat liver nuclear extracts. Of these three regions, only the HS3D binding site is located within the functionally identified hormonally responsive segment of IGF-I exon 1. These results directly implicate PKA in the control of IGF-I gene transcription by PGE2 and identify a segment of

  1. An IGF-I promoter polymorphism modifies the relationships between birth weight and risk factors for cardiovascular disease and diabetes at age 36

    Directory of Open Access Journals (Sweden)

    Stehouwer Coen DA

    2005-06-01

    Full Text Available Abstract Objective To investigate whether IGF-I promoter polymorphism was associated with birth weight and risk factors for cardiovascular disease (CVD and type 2 diabetes (T2DM, and whether the birth weight – risk factor relationship was the same for each genotype. Design and participants 264 subjects (mean age 36 years had data available on birth weight, IGF-I promoter polymorphism genotype, CVD and T2DM risk factors. Student's t-test and regression analyses were applied to analyse differences in birth weight and differences in the birth weight – risk factors relationship between the genotypes. Results Male variant carriers (VCs of the IGF-I promoter polymorphism had a 0.2 kg lower birth weight than men with the wild type allele (p = 0.009. Of the risk factors for CVD and T2DM, solely LDL concentration was associated with the genotype for the polymorphism. Most birth weight – risk factor relationships were stronger in the VC subjects; among others the birth weight – systolic blood pressure relationship: 1 kg lower birth weight was related to an 8.0 mmHg higher systolic blood pressure Conclusion The polymorphism in the promoter region of the IGF-I gene is related to birth weight in men only, and to LDL concentration only. Furthermore, the genotype for this polymorphism modified the relationships between birth weight and the risk factors, especially for systolic and diastolic blood pressure.

  2. Clinical singnificance of determination of changes of serum and peritoneal fluid TGF-β, IGF-I, TNF-α and IL-8 levels in patients with endometriosis

    International Nuclear Information System (INIS)

    Zao Yuhua; Zhang Juhong; Ma Yunbao

    2006-01-01

    Objective: To investigate the clinical significance of the changes of serum and peritioneal fluid TGF-β, IGF - I , TNF-α and IL-8 levels in patients with endometriosis. Methods: Serum and peritoneal fluid levels of TGF-β, IGF-I, TNF-α and IL-8 were measured with RIA in 30 patients with endometriosis and 30 controls. Results: The levels of TGF-β, IGF-I, TNF-α and IL-8 in serum and peritoneal fluid in endometriosis group were significantly higher than those in the controls (P<0.05), moreover, the levels of the markers in peritoneal fluid were significantly higher than those in serum (P<0.05). Conclusion: It is likely that elevation of serum and peritoneal fluid levels of the markers may play a role in the pathogenesis of endometriosis. (authors)

  3. Maternal exposure to UV filters and associations to maternal thyroid hormones and IGF-I/IGFBP3 and birth outcomes

    DEFF Research Database (Denmark)

    Krause, Marianna; Frederiksen, Hanne; Sundberg, Karin

    2018-01-01

    as birth outcomes (weight, height, and head and abdominal circumferences) were examined. RESULTS: Positive associations between maternal serum concentrations of 4-HBP and triiodothyronine (T3), thyroxine (T4), Insulin-like Growth Factor-I (IGF-I) and its binding protein IGFBP3, were observed in mothers...

  4. IGF1R- and ROR1-Specific CAR T Cells as a Potential Therapy for High Risk Sarcomas.

    Directory of Open Access Journals (Sweden)

    Xin Huang

    Full Text Available Patients with metastatic or recurrent and refractory sarcomas have a dismal prognosis. Therefore, new targeted therapies are urgently needed. This study was designed to evaluate chimeric antigen receptor (CAR T cells targeting the type I insulin-like growth factor receptor (IGF1R or tyrosine kinase-like orphan receptor 1 (ROR1 molecules for their therapeutic potential against sarcomas. Here, we report that IGF1R (15/15 and ROR1 (11/15 were highly expressed in sarcoma cell lines including Ewing sarcoma, osteosarcoma, alveolar or embryonal rhabdomyosarcoma, and fibrosarcoma. IGF1R and ROR1 CAR T cells derived from eight healthy donors using the Sleeping Beauty (SB transposon system were cytotoxic against sarcoma cells and produced high levels of IFN-γ, TNF-α and IL-13 in an antigen-specific manner. IGF1R and ROR1 CAR T cells generated from three sarcoma patients released significant amounts of IFN-γ in response to sarcoma stimulation. The adoptive transfer of IGF1R and ROR1 CAR T cells derived from a sarcoma patient significantly reduced tumor growth in pre-established, systemically disseminated and localized osteosarcoma xenograft models in NSG mice. Infusion of IGF1R and ROR1 CAR T cells also prolonged animal survival in a localized sarcoma model using NOD/scid mice. Our data indicate that both IGF1R and ROR1 can be effectively targeted by SB modified CAR T cells and that such CAR T cells may be useful in the treatment of high risk sarcoma patients.

  5. IGF system targeted therapy: Therapeutic opportunities for ovarian cancer.

    Science.gov (United States)

    Liefers-Visser, J A L; Meijering, R A M; Reyners, A K L; van der Zee, A G J; de Jong, S

    2017-11-01

    The insulin-like growth factor (IGF) system comprises multiple growth factor receptors, including insulin-like growth factor 1 receptor (IGF-1R), insulin receptor (IR) -A and -B. These receptors are activated upon binding to their respective growth factor ligands, IGF-I, IGF-II and insulin, and play an important role in development, maintenance, progression, survival and chemotherapeutic response of ovarian cancer. In many pre-clinical studies anti-IGF-1R/IR targeted strategies proved effective in reducing growth of ovarian cancer models. In addition, anti-IGF-1R targeted strategies potentiated the efficacy of platinum based chemotherapy. Despite the vast amount of encouraging and promising pre-clinical data, anti-IGF-1R/IR targeted strategies lacked efficacy in the clinic. The question is whether targeting the IGF-1R/IR signaling pathway still holds therapeutic potential. In this review we address the complexity of the IGF-1R/IR signaling pathway, including receptor heterodimerization within and outside the IGF system and downstream signaling. Further, we discuss the implications of this complexity on current targeted strategies and indicate therapeutic opportunities for successful targeting of the IGF-1R/IR signaling pathway in ovarian cancer. Multiple-targeted approaches circumventing bidirectional receptor tyrosine kinase (RTK) compensation and prevention of system rewiring are expected to have more therapeutic potential. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  6. The potential role of IGF-I receptor mRNA in rats with diabetic retinopathy

    Institute of Scientific and Technical Information of China (English)

    匡洪宇; 邹伟; 刘丹; 史榕荇; 程丽华; 殷慧清; 刘晓民

    2003-01-01

    Objective To evaluate the potential role of insulin-like growth factor-1 receptor mRNA(IGF-IR mRNA) in the onset and development of retinopathy in diabetic rats.Methods A diabetic model was duplicated in Wistar rats. The early changes in the retina were examined using light and transmission electron microscopy. Expression of IGF-IR mRNA was analyzed using in situ hybridization.Results Weak expression of IGF-IR mRNA(5%) was found in retinas of normal rats, but was significantly increased (15% and 18%) in the retinas of diabetic rats after 3 and 6 months of diabetes (P<0.01). In situ hybridization and morphological study demonstrated that there was a positive correlation between IGF-IR mRNA expression and retinal changes at various stages.Conclusion Increased IGF-IR mRNA might play an important role in the onset and development of diabetic retinopathy.

  7. Growth hormone/IGF-1 axis longitudinal evaluation in clinically isolated syndrome patients on interferon β-1b therapy: stimulation tests and correlations with clinical and radiological conversion to multiple sclerosis.

    Science.gov (United States)

    Lanzillo, R; Di Somma, C; Quarantelli, M; Carotenuto, A; Pivonello, C; Moccia, M; Cianflone, A; Marsili, A; Puorro, G; Saccà, F; Russo, C V; De Luca Picione, C; Ausiello, F; Colao, A; Brescia Morra, V

    2017-02-01

    Growth hormone (GH)/insulin-like growth factor 1 (IGF-1) axis abnormalities in multiple sclerosis (MS) suggest their role in its pathogenesis. Interferon β (IFN-β) efficacy could be mediated also by an increase of IGF-1 levels. A 2-year longitudinal study was performed to estimate the prevalence of GH and/or IGF-1 deficiency in clinically isolated syndrome (CIS) patients and their correlation with conversion to MS in IFN treated patients. Clinical and demographic features of CIS patients were collected before the start of IFN-β-1b. IGF-1 levels and GH response after arginine and GH releasing hormone + arginine stimulation tests were assessed. Clinical and magnetic resonance imaging evaluations were performed at baseline, 1 year and 2 years. Thirty CIS patients (24 female) were enrolled. At baseline, four patients (13%) showed a hypothalamic GH deficiency (GHD), whilst no one had a pituitary GHD. Baseline demographic, clinical and radiological data were not related to GHD, whilst IGF-1 levels were inversely related to age (P IGF-1 serum mean levels were not significantly modified after 1 and 2 years of treatment in the whole group, although 3/4 GHD patients experienced a normalization of GH levels, whilst one dropped out. After 2 years of treatment 13/28 (46%) patients converted to MS. The presence of GHD and GH and IGF-1 levels were not predictive of relapses, new T2 lesions or conversion occurrence. Growth hormone/IGF-1 axis function was found to be frequently altered in CIS patients, but this was not related to MS conversion. Patients experienced an improvement of GHD during IFN therapy. Longer follow-up is necessary to assess its impact on disease progression. © 2016 EAN.

  8. Phosphorylation of human skeletal muscle myosin

    International Nuclear Information System (INIS)

    Houston, M.E.; Lingley, M.D.; Stuart, D.S.; Hoffman-Goetz, L.

    1986-01-01

    Phosphorylation of the P-light chains (phosphorylatable light chains) in human skeletal muscle myosin was studied in vitro and in vivo under resting an d contracted conditions. biopsy samples from rested vastus lateralis muscle of male and female subjects were incubated in oxygenated physiological solution at 30 0 C. Samples frozen following a quiescent period showed the presence of only unphosphorylated P-light chains designated LC2f (light chain two of fast myosin) CL2s and LC2s'(light chains two of slow myosin). Treatment with caffeine (10 mM) or direct electrical stimulation resulted in the appearance of three additional bands which were identified as the phosphorylated forms of the P-light chains i.e. LC2f-P, LC2s-P and LC2s'-P. The presence of phosphate was confirmed by prior incubation with ( 30 P) orthophosphate. Muscle samples rapidly frozen from resting vastus lateralis muscle revealed the presence of unphosphorylated and phosphorylated P-light chains in approximately equal ratios. Muscle samples rapidly frozen following a maximal 10 second isometric contraction showed virtually only phosphorylated fast and slow P-light chains. These results reveal that the P-light chains in human fast and slow myosin may be rapidly phosphorylated, but the basal level of phosphorylation in rested human muscle considerably exceeds that observed in animal muscles studied in vitro or in situ

  9. A Concerted Action Of Estradiol And Insulin Like Growth Factor I Underlies Sex Differences In Mood Regulation By Exercise.

    Science.gov (United States)

    Munive, Victor; Santi, Andrea; Torres-Aleman, Ignacio

    2016-05-12

    Mood homeostasis present sexually dimorphic traits which may explain sex differences in the incidence of mood disorders. We explored whether diverse behavioral-setting components of mood may be differentially regulated in males and females by exercise, a known modulator of mood. We found that exercise decreases anxiety only in males. Conversely, exercise enhanced resilience to stress and physical arousal, two other important components of mood, only in females. Because exercise increases brain input of circulating insulin-like growth factor I (IGF-I), a potent modulator of mood, we explored whether sex-specific actions of exercise on mood homeostasis relate to changes in brain IGF-I input. We found that exercise increased hippocampal IGF-I levels only in cycling females. Underlying mechanism involved activation of estrogen (E2) receptors in brain vessels that led to increased uptake of serum IGF-I as E2 was found to stimulate IGF-I uptake in brain endothelial cells. Indeed, modulatory effects of exercise on mood were absent in female mice with low serum IGF-I levels or after either ovariectomy or administration of an E2 receptor antagonist. These results suggest that sex-specific brain IGF-I responses to physiological stimuli such as exercise contribute to dimorphic mood homeostasis that may explain sex differences in affective disorders.

  10. IGF-1, IGFBP-1, and IGFBP-3 polymorphisms predict circulating IGF levels but not breast cancer risk: findings from the Breast and Prostate Cancer Cohort Consortium (BPC3.

    Directory of Open Access Journals (Sweden)

    Alpa V Patel

    2008-07-01

    Full Text Available IGF-1 has been shown to promote proliferation of normal epithelial breast cells, and the IGF pathway has also been linked to mammary carcinogenesis in animal models. We comprehensively examined the association between common genetic variation in the IGF1, IGFBP1, and IGFBP3 genes in relation to circulating IGF-I and IGFBP-3 levels and breast cancer risk within the NCI Breast and Prostate Cancer Cohort Consortium (BPC3. This analysis included 6,912 breast cancer cases and 8,891 matched controls (n = 6,410 for circulating IGF-I and 6,275 for circulating IGFBP-3 analyses comprised primarily of Caucasian women drawn from six large cohorts. Linkage disequilibrium and haplotype patterns were characterized in the regions surrounding IGF1 and the genes coding for two of its binding proteins, IGFBP1 and IGFBP3. In total, thirty haplotype-tagging single nucleotide polymorphisms (htSNP were selected to provide high coverage of common haplotypes; the haplotype structure was defined across four haplotype blocks for IGF1 and three for IGFBP1 and IGFBP3. Specific IGF1 SNPs individually accounted for up to 5% change in circulating IGF-I levels and individual IGFBP3 SNPs were associated up to 12% change in circulating IGFBP-3 levels, but no associations were observed between these polymorphisms and breast cancer risk. Logistic regression analyses found no associations between breast cancer and any htSNPs or haplotypes in IGF1, IGFBP1, or IGFBP3. No effect modification was observed in analyses stratified by menopausal status, family history of breast cancer, body mass index, or postmenopausal hormone therapy, or for analyses stratified by stage at diagnosis or hormone receptor status. In summary, the impact of genetic variation in IGF1 and IGFBP3 on circulating IGF levels does not appear to substantially influence breast cancer risk substantially among primarily Caucasian postmenopausal women.

  11. Crystal structure of <i>B> <i>acillus anthracisi> virulence regulator AtxA and effects of phosphorylated histidines on multimerization and activity: AtxA multimerization, phosphorylation and activity

    Energy Technology Data Exchange (ETDEWEB)

    Hammerstrom, Troy G.; Lori, Horton B.; Swick, Michelle C.; Joachimiak, Andrzej; Osipiuk, Jerzy; Koehler, Theresa M.

    2014-12-30

    The Bacillus anthracis virulence regulator AtxA controls transcription of the anthrax toxin genes and capsule biosynthetic operon. AtxA activity is elevated during growth in media containing glucose and CO2/bicarbonate, and there is a positive correlation between the CO2/bicarbonate signal, AtxA activity and homomultimerization. AtxA activity is also affected by phosphorylation at specific histidines. We show that AtxA crystallizes as a dimer. Distinct folds associated with predicted DNA-binding domains (HTH1 and HTH2) and phosphoenolpyruvate: carbohydrate phosphotransferase system-regulated domains (PRD1 and PRD2) are apparent. We tested AtxA variants containing single and double phosphomimetic (HisAsp) and phosphoablative (HisAla) amino acid changes for activity in B.anthracis cultures and for protein-protein interactions in cell lysates. Reduced activity of AtxA H199A, lack of multimerization and activity of AtxAH379D variants, and predicted structural changes associated with phosphorylation support a model for control of AtxA function. We propose that (i) in the AtxA dimer, phosphorylation of H199 in PRD1 affects HTH2 positioning, influencing DNA-binding; and (ii) phosphorylation of H379 in PRD2 disrupts dimer formation. The AtxA structure is the first reported high-resolution full-length structure of a PRD-containing regulator, and can serve as a model for proteins of this family, especially those that link virulence to bacterial metabolism.

  12. Autocrine IGF-1 Action in Adipocytes Controls Systemic IGF-1 Concentrations and Growth

    OpenAIRE

    Kl?ting, Nora; Koch, Linda; Wunderlich, Thomas; Kern, Matthias; Ruschke, Karen; Krone, Wilhelm; Br?ning, Jens C.; Bl?her, Matthias

    2008-01-01

    OBJECTIVE?IGF-1 and the IGF-1 receptor (IGF-1R) have been implicated in the regulation of adipocyte differentiation and lipid accumulation in vitro. RESEARCH DESIGN AND METHODS?To investigate the role of IGF-1 receptor in vivo, we have inactivated the Igf-1r gene in adipose tissue (IGF-1RaP2Cre mice) using conditional gene targeting strategies. RESULTS?Conditional IGF-1R inactivation resulted in increased adipose tissue mass with a predominantly increased lipid accumulation in epigonadal fat ...

  13. Alterations in vasodilator-stimulated phosphoprotein (VASP) phosphorylation: associations with asthmatic phenotype, airway inflammation and β2-agonist use

    Science.gov (United States)

    Hastie, Annette T; Wu, Min; Foster, Gayle C; Hawkins, Gregory A; Batra, Vikas; Rybinski, Katherine A; Cirelli, Rosemary; Zangrilli, James G; Peters, Stephen P

    2006-01-01

    Background Vasodilator-stimulated phosphoprotein (VASP) mediates focal adhesion, actin filament binding and polymerization in a variety of cells, thereby inhibiting cell movement. Phosphorylation of VASP via cAMP and cGMP dependent protein kinases releases this "brake" on cell motility. Thus, phosphorylation of VASP may be necessary for epithelial cell repair of damage from allergen-induced inflammation. Two hypotheses were examined: (1) injury from segmental allergen challenge increases VASP phosphorylation in airway epithelium in asthmatic but not nonasthmatic normal subjects, (2) regular in vivo β2-agonist use increases VASP phosphorylation in asthmatic epithelium, altering cell adhesion. Methods Bronchial epithelium was obtained from asthmatic and non-asthmatic normal subjects before and after segmental allergen challenge, and after regularly inhaled albuterol, in three separate protocols. VASP phosphorylation was examined in Western blots of epithelial samples. DNA was obtained for β2-adrenergic receptor haplotype determination. Results Although VASP phosphorylation increased, it was not significantly greater after allergen challenge in asthmatics or normals. However, VASP phosphorylation in epithelium of nonasthmatic normal subjects was double that observed in asthmatic subjects, both at baseline and after challenge. Regularly inhaled albuterol significantly increased VASP phosphorylation in asthmatic subjects in both unchallenged and antigen challenged lung segment epithelium. There was also a significant increase in epithelial cells in the bronchoalveolar lavage of the unchallenged lung segment after regular inhalation of albuterol but not of placebo. The haplotypes of the β2-adrenergic receptor did not appear to associate with increased or decreased phosphorylation of VASP. Conclusion Decreased VASP phosphorylation was observed in epithelial cells of asthmatics compared to nonasthmatic normals, despite response to β-agonist. The decreased

  14. Alterations in vasodilator-stimulated phosphoprotein (VASP phosphorylation: associations with asthmatic phenotype, airway inflammation and β2-agonist use

    Directory of Open Access Journals (Sweden)

    Cirelli Rosemary

    2006-02-01

    Full Text Available Abstract Background Vasodilator-stimulated phosphoprotein (VASP mediates focal adhesion, actin filament binding and polymerization in a variety of cells, thereby inhibiting cell movement. Phosphorylation of VASP via cAMP and cGMP dependent protein kinases releases this "brake" on cell motility. Thus, phosphorylation of VASP may be necessary for epithelial cell repair of damage from allergen-induced inflammation. Two hypotheses were examined: (1 injury from segmental allergen challenge increases VASP phosphorylation in airway epithelium in asthmatic but not nonasthmatic normal subjects, (2 regular in vivo β2-agonist use increases VASP phosphorylation in asthmatic epithelium, altering cell adhesion. Methods Bronchial epithelium was obtained from asthmatic and non-asthmatic normal subjects before and after segmental allergen challenge, and after regularly inhaled albuterol, in three separate protocols. VASP phosphorylation was examined in Western blots of epithelial samples. DNA was obtained for β2-adrenergic receptor haplotype determination. Results Although VASP phosphorylation increased, it was not significantly greater after allergen challenge in asthmatics or normals. However, VASP phosphorylation in epithelium of nonasthmatic normal subjects was double that observed in asthmatic subjects, both at baseline and after challenge. Regularly inhaled albuterol significantly increased VASP phosphorylation in asthmatic subjects in both unchallenged and antigen challenged lung segment epithelium. There was also a significant increase in epithelial cells in the bronchoalveolar lavage of the unchallenged lung segment after regular inhalation of albuterol but not of placebo. The haplotypes of the β2-adrenergic receptor did not appear to associate with increased or decreased phosphorylation of VASP. Conclusion Decreased VASP phosphorylation was observed in epithelial cells of asthmatics compared to nonasthmatic normals, despite response to

  15. Phosphorylation and activation of p42 and p44 mitogen-activated protein kinase are required for the P2 purinoceptor stimulation of endothelial prostacyclin production.

    Science.gov (United States)

    Patel, V; Brown, C; Goodwin, A; Wilkie, N; Boarder, M R

    1996-11-15

    Extracellular ATP and ADP, released from platelets and other sites stimulate the endothelial production of prostacyclin (PGI2) by acting on G-protein-coupled P2Y2 and P2Y2 purinoceptors, contributing to the maintenance of a non-thrombogenic surface. The mechanism, widely described as being dependent on elevated cytosolic [Ca2+], also requires protein tyrosine phosphorylation. Here we show that activation of both these P2 receptor types leads to the tyrosine phosphorylation and activation of both the p42 and p44 forms of mitogen-activated protein kinase (MAPK). 2-Methylthio-ATP and UTP, selectively activating P2Y1 and P2Y2 purinoceptors respectively, and ATP, a non-selective agonist at these two receptors, stimulate the tyrosine phosphorylation of both p42mapk and p44mapk, as revealed by Western blots with an antiserum specific for the tyrosine-phosphorylated forms of the enzymes. By using separation on Resource Q columns, peptide kinase activity associated with the phosphorylated MAPK enzymes distributes into two peaks, one mainly p42mapk and one mainly p44mapk, both of which are stimulated by ATP with respect to kinase activity and phospho-MAPK immunoreactivity. Stimulation of P2Y1 or P2Y2 purinoceptors leads to a severalfold increase in PGI2 efflux; this was blocked in a dose-dependent manner by the selective MAPK kinase inhibitor PD98059. This drug also blocked the agonist-stimulated increase in phospho-MAPK immunoreactivity for both p42mapk and p44mapk but left the phospholipase C response to P2 agonists essentially unchanged. Olomoucine has been reported to inhibit p44mapk activity. Here we show that in the same concentration range olomoucine inhibits activity in both peaks from the Resource Q column and also the agonist stimulation of 6-keto-PGF1, but has no effect on agonist-stimulated phospho-MAPK immunoreactivity. These results provide direct evidence for the involvement of p42 and p44 MAPK in the PGI2 response of intact endothelial cells: we have shown

  16. Inhibitory effect of SPE-39 due to tyrosine phosphorylation and ubiquitination on the function of Vps33B in the EGF-stimulated cells.

    Science.gov (United States)

    Ishii, Ayumi; Kamimori, Kanae; Hiyoshi, Mineyoshi; Kido, Hiroshi; Ohta, Takeshi; Konishi, Hiroaki

    2012-07-30

    Although SPE-39 is a binding protein to Vps33B that is one of the subunit in the mammalian HOPS complex, the elements of SPE-39 function remain unknown. Here, we show that tyrosine phosphorylation of SPE-39 following EGF stimulation plays a role in the stability of SPE-39 itself. Ubiquitination of the C-terminal region of SPE-39 was also elevated in response to EGF stimulation, and this process was regulated by the phosphorylation of Tyr-11 in SPE-39. However, association of Vps33B with SPE-39 inhibited the elevation of ubiquitination of SPE-39 following EGF stimulation, which might be responsible for the stabilization of SPE-39. Furthermore, an opposing functional relationship between SPE-39 and Vps33B on the downregulation of the EGF receptor was observed in EGF-stimulated COS-7 cells. Copyright © 2012 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  17. Endothelin-1 stimulates catalase activity through the PKCδ mediated phosphorylation of Serine 167

    Science.gov (United States)

    Rafikov, Ruslan; Kumar, Sanjiv; Aggarwal, Saurabh; Hou, Yali; Kangath, Archana; Pardo, Daniel; Fineman, Jeffrey R.; Black, Stephen M.

    2013-01-01

    Our previous studies have shown that endothelin-1 (ET-1) stimulates catalase activity in endothelial cells and lambs with acute increases in pulmonary blood flow (PBF), without altering gene expression. The purpose of this study was to investigate the molecular mechanism by which this occurs. Exposing pulmonary arterial endothelial cells (PAEC) to ET-1 increased catalase activity and decreased cellular hydrogen peroxide (H2O2) levels. These changes correlated with an increase in serine phosphorylated catalase. Using the inhibitory peptide δV1.1, this phosphorylation was shown to be PKCδ dependent. Mass spectrometry identified serine167 as the phosphorylation site. Site-directed mutagenesis was used to generate a phospho-mimic (S167D) catalase. Activity assays using recombinant protein purified from E.coli or transiently transfected COS-7 cells, demonstrated that S167D-catalase had an increased ability to degrade H2O2 compared to the wildtype enzyme. Using a phospho-specific antibody, we were able to verify that pS167 catalase levels are modulated in lambs with acute increases in PBF in the presence and absence of the ET receptor antagonist, tezosentan. S167 is being located on the dimeric interface suggesting it could be involved in regulating the formation of catalase tetramers. To evaluate this possibility we utilized analytical gel-filtration to examine the multimeric structure of recombinant wildtype- and S167D-catalase. We found that recombinant wildtype catalase was present as a mixture of monomers and dimers while S167D catalase was primarily tetrameric. Further, the incubation of wildtype catalase with PKCδ was sufficient to convert wildtype catalase into a tetrameric structure. In conclusion, this is the first report indicating that the phosphorylation of catalase regulates its multimeric structure and activity. PMID:24211614

  18. Effects of Moderate Aerobic Exercise Combined With Caloric Restriction on Circulating Estrogens and IGF-I in Premenopausal Women

    National Research Council Canada - National Science Library

    Williams, Nancy

    2002-01-01

    ... cancer, circulating estrogens and IGF-I. We will also test whether this type of diet/exercise program will produce significant reductions in the peripheral production of estrone by adipose tissue through its impact on the reduction of fat mass...

  19. Investigating the role of uncoupling of Troponin I phosphorylation from changes in myofibrillar Ca2+-sensitivity in the pathogenesis of Cardiomyopathy

    Directory of Open Access Journals (Sweden)

    Andrew Easton Messer

    2014-08-01

    Full Text Available Contraction in the mammalian heart is controlled by the intracellular Ca2+ concentration as it is in all striated muscle, but the heart has an additional signalling system that comes into play to increase heart rate and cardiac output during exercise or stress. β-adrenergic stimulation of heart muscle cells leads to release of cyclic-AMP and the activation of protein kinase A which phosphorylates key proteins in the sarcolemma, sarcoplasmic reticulum and contractile apparatus. Troponin I (TnI and Myosin Binding Protein C (MyBP-C are the prime targets in the myofilaments. TnI phosphorylation lowers myofibrillar Ca2+-sensitivity and increases the speed of Ca2+-dissociation and relaxation (lusitropic effect.Recent studies have shown that this relationship between Ca2+-sensitivity and TnI phosphorylation may be unstable. In familial cardiomyopathies, both dilated and hypertrophic (DCM and HCM, a mutation in one of the proteins of the thin filament often results in the loss of the relationship (uncoupling and blunting of the lusitropic response. For familial dilated cardiomyopathy in thin filament proteins it has been proposed that this uncoupling is causative of the phenotype. Uncoupling has also been found in human heart tissue from patients with hypertrophic obstructive cardiomyopathy as a secondary effect. Recently, it has been found that Ca2+-sensitizing drugs can promote uncoupling, whilst one Ca2+-desensitising drug Epigallocatechin 3-Gallate (EGCG can reverse uncoupling.We will discuss recent findings about the role of uncoupling in the development of cardiomyopathies and the molecular mechanism of the process.

  20. Insulin-like growth factor 1 (IGF-1): a growth hormone

    Science.gov (United States)

    Laron, Z

    2001-01-01

    Aim—To contribute to the debate about whether growth hormone (GH) and insulin-like growth factor 1 (IGF-1) act independently on the growth process. Methods—To describe growth in human and animal models of isolated IGF-1 deficiency (IGHD), such as in Laron syndrome (LS; primary IGF-1 deficiency and GH resistance) and IGF-1 gene or GH receptor gene knockout (KO) mice. Results—Since the description of LS in 1966, 51 patients were followed, many since infancy. Newborns with LS are shorter (42–47 cm) than healthy babies (49–52 cm), suggesting that IGF-1 has some influence on intrauterine growth. Newborn mice with IGF-1 gene KO are 30% smaller. The postnatal growth rate of patients with LS is very slow, the distance from the lowest normal centile increasing progressively. If untreated, the final height is 100–136 cm for female and 109–138 cm for male patients. They have acromicia, organomicria including the brain, heart, gonads, genitalia, and retardation of skeletal maturation. The availability of biosynthetic IGF-1 since 1988 has enabled it to be administered to children with LS. It accelerated linear growth rates to 8–9 cm in the first year of treatment, compared with 10–12 cm/year during GH treatment of IGHD. The growth rate in following years was 5–6.5 cm/year. Conclusion—IGF-1 is an important growth hormone, mediating the protein anabolic and linear growth promoting effect of pituitary GH. It has a GH independent growth stimulating effect, which with respect to cartilage cells is possibly optimised by the synergistic action with GH. PMID:11577173

  1. IGF-II is up-regulated and myofibres are hypertrophied in regenerating soleus of mice lacking FGF6

    International Nuclear Information System (INIS)

    Armand, Anne-Sophie; Lecolle, Sylvie; Launay, Thierry; Pariset, Claude; Fiore, Frederic; Della Gaspera, Bruno; Birnbaum, Daniel; Chanoine, Christophe; Charbonnier, Frederic

    2004-01-01

    Important functions in myogenesis have been proposed for FGF6, a member of the fibroblast growth factor family accumulating almost exclusively in the myogenic lineage. However, the use of FGF6(-/-) mutant mice gave contradictory results and the role of FGF6 during myogenesis remains largely unclear. Using FGF6(-/-) mice, we first analysed the morphology of the regenerated soleus following cardiotoxin injection and showed hypertrophied myofibres in soleus of the mutant mice as compared to wild-type mice. Secondly, to examine the function of the IGF family in the hypertrophy process, we used semiquantitative and real-time RT-PCR assays and Western blots to monitor the expression of the insulin-like growth factors (IGF-I and IGF-II), their receptors [type I IGF receptor (IGF1R) and IGF-II receptor (IGF2R)], and of a binding protein IGFBP-5 in regenerating soleus muscles of FGF6(-/-) knockout mice vs. wild-type mice. In the mutant, both IGF-II and IGF2R, but not IGF-I and IGF1R, were strongly up-regulated, whereas IGFBP5 was down-regulated, strongly suggesting that, in the absence of FGF6, the mechanisms leading to myofibre hypertrophy were mediated specifically by an IGF-II/IGF2R signalling pathway distinct from the classic mechanism involving IGF-I and IGF1R previously described for skeletal muscle hypertrophy. The potential regulating role of IGFBP5 on IGF-II expression is also discussed. This report shows for the first time a specific role for FGF6 in the regulation of myofibre size during a process of in vivo myogenesis

  2. Activation of IGF-1/IGFBP-3 signaling by berberine improves intestinal mucosal barrier of rats with acute endotoxemia.

    Science.gov (United States)

    He, Yan; Yuan, Xiaoming; Zhou, Guangrong; Feng, Aiwen

    2018-01-01

    Insulin-like growth factor I (IGF-I) and binding protein 3 (IGFBP-3) play a role in the maintenance of gut mucosal barrier function. Nevertheless, IGF-I/IGFBP-3 and tight junction protein (TJP) expression in small intestinal mucosa are often impaired during endotoxemia. In this model of acute endotoxemia, the regulatory effect of berberine on IGF-I/IGFBP-3 and TJP expression in ileal mucosa was evaluated. The findings revealed systemic injection of lipopolysaccharide (LPS) suppressed mRNA and protein expression of IGF-I and IGFBP-3, but berberine ameliorated their production. LPS injection inhibited occludin and claudin-1 protein generation, and this inhibitory effect of LPS was abolished by berberine. Inhibition of IGF-I/IGFBP-3 signaling by AG1024 or siRNAs reduced berberine-induced occludin and claudin-1 production. Additionally, GW9662 was found to repress berberine-induced IGF-I/IGFBP-3 expression, indicating of a cross-link between PPARγ and IGF-I/IGFBP-3 axis. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Cardioprotective role of IGF-1 in the hypertrophied myocardium of the spontaneously hypertensive rats: A key effect on NHE-1 activity.

    Science.gov (United States)

    Yeves, A M; Burgos, J I; Medina, A J; Villa-Abrille, M C; Ennis, I L

    2018-05-13

    Myocardial Na + /H + exchanger-1 (NHE-1) hyperactivity and oxidative stress are interrelated phenomena playing pivotal roles in the development of pathological cardiac hypertrophy and heart failure. Exercise training is effective to convert pathological into physiological hypertrophy in the spontaneously hypertensive rats (SHR), and IGF-1-key humoral mediator of exercise training-inhibits myocardial NHE-1, at least in normotensive rats. Therefore, we hypothesize that IGF-1 by hampering NHE-1 hyperactivity and oxidative stress should exert a cardioprotective effect in the SHR. NHE-1 activity [proton efflux (JH+) mmol L -1  min -1 ], expression and phosphorylation; H 2 O 2 production; superoxide dismutase (SOD) activity; contractility and calcium transients were measured in SHR hearts in the presence/absence of IGF-1. IGF-1 significantly decreased NHE-1 activity (JH+ at pH i 6.95: 1.39 ± 0.32, n = 9 vs C 3.27 ± 0.3, n = 20, P IGF-1 receptor (2.7 ± 0.4, n = 7); by the PI3K inhibitor wortmannin (3.14 ± 0.41, n = 7); and the AKT inhibitor MK2206 (3.37 ± 0.43, n = 14). Moreover, IGF-1 exerted an antioxidant effect revealed by a significant reduction in H 2 O 2 production accompanied by an increase in SOD activity. In addition, IGF-1 improved cardiomyocyte contractility as evidenced by an increase in sarcomere shortening and a decrease in the relaxation constant, underlined by an increase in the amplitude and rate of decay of the calcium transients. IGF-1 exerts a cardioprotective role on the hypertrophied hearts of the SHR, in which the inhibition of NHE-1 hyperactivity, as well as the positive inotropic and antioxidant effects, emerges as key players. © 2018 Scandinavian Physiological Society. Published by John Wiley & Sons Ltd.

  4. Restoration of radiation therapy-induced salivary gland dysfunction in mice by post therapy IGF-1 administration

    International Nuclear Information System (INIS)

    Grundmann, Oliver; Fillinger, Jamia L; Victory, Kerton R; Burd, Randy; Limesand, Kirsten H

    2010-01-01

    Radiotherapy for head and neck cancer results in severe and chronic salivary gland dysfunction in most individuals. This results in significant side effects including xerostomia, dysphagia, and malnutrition which are linked to significant reductions in patients' quality of life. Currently there are few xerostomia treatment approaches that provide long-term results without significant side effects. To address this problem we investigated the potential for post-therapeutic IGF-1 to reverse radiation-induced salivary gland dysfunction. FVB mice were treated with targeted head and neck radiation and significant reductions in salivary function were confirmed 3 days after treatment. On days 4-8 after radiation, one group of mice was injected intravenously with IGF-1 while a second group served as a vehicle control. Stimulated salivary flow rates were evaluated on days 30, 60, and 90 and histological analysis was performed on days 9, 30, 60, and 90. Irradiated animals receiving vehicle injections have 40-50% reductions in stimulated salivary flow rates throughout the entire time course. Mice receiving injections of IGF-1 have improved stimulated salivary flow rates 30 days after treatment. By days 60-90, IGF-1 injected mice have restored salivary flow rates to unirradiated control mice levels. Parotid tissue sections were stained for amylase as an indicator of functioning acinar cells and significant reductions in total amylase area are detected in irradiated animals compared to unirradiated groups on all days. Post-therapeutic injections of IGF-1 results in increased amylase-positive acinar cell area and improved amylase secretion. Irradiated mice receiving IGF-1 show similar proliferation indices as untreated mice suggesting a return to tissue homeostasis. Post-therapeutic IGF-1 treatment restores salivary gland function potentially through normalization of cell proliferation and improved expression of amylase. These findings could aid in the rational design of

  5. A fractionation method to identify qauntitative changes in protein expression mediated by IGF-1 on the proteome of murine C2C12 myoblasts

    Directory of Open Access Journals (Sweden)

    Friedmann Theodore

    2009-08-01

    Full Text Available Abstract Although much is known about signal transduction downstream of insulin-like growth factor-1 (IGF-1, relatively little is known about the global changes in protein expression induced by this hormone. In this study, the acute effects of IGF-1 on the proteome of murine C2C12 cells were examined. Cells were treated with IGF-1 for up to 24 hours, lysed, and fractionated into cytosolic, nuclear, and insoluble portions. Proteins from the cytosolic fraction were further separated using a new batch ion-exchange chromatography method to reduce sample complexity, followed by two-dimensional (2D electrophoresis, and identification of selected proteins by mass spectrometry. PDQuest software was utilized to identify and catalogue temporal changes in protein expression during IGF-1 stimulation. In response to IGF-1 stimulation, expression of 23 proteins increased at least three-fold and expression of 17 proteins decreased at least three-fold compared with control un-stimulated C2C12 cells. Changes in expression of selected proteins from each group, including Rho-GDI, cofillin, RAD50, enolase, IκB kinase b (IκBKb and Hsp70 were confirmed by Western blotting. Additionally, the position of 136 'landmark' proteins whose expression levels and physicochemical properties did not change appreciably or consistently during IGF-1 treatment were mapped and identified. This characterization of large-scale changes in protein expression in response to growth factor stimulation of C2C12 cells will further help to establish a comprehensive understanding of the networks and pathways involved in the action of IGF-1.

  6. PKCδ-mediated IRS-1 Ser24 phosphorylation negatively regulates IRS-1 function

    International Nuclear Information System (INIS)

    Greene, Michael W.; Ruhoff, Mary S.; Roth, Richard A.; Kim, Jeong-a; Quon, Michael J.; Krause, Jean A.

    2006-01-01

    The IRS-1 PH and PTB domains are essential for insulin-stimulated IRS-1 Tyr phosphorylation and insulin signaling, while Ser/Thr phosphorylation of IRS-1 disrupts these signaling events. To investigate consensus PKC phosphorylation sites in the PH-PTB domains of human IRS-1, we changed Ser24, Ser58, and Thr191 to Ala (3A) or Glu (3E), to block or mimic phosphorylation, respectively. The 3A mutant abrogated the inhibitory effect of PKCδ on insulin-stimulated IRS-1 Tyr phosphorylation, while reductions in insulin-stimulated IRS-1 Tyr phosphorylation, cellular proliferation, and Akt activation were observed with the 3E mutant. When single Glu mutants were tested, the Ser24 to Glu mutant had the greatest inhibitory effect on insulin-stimulated IRS-1 Tyr phosphorylation. PKCδ-mediated IRS-1 Ser24 phosphorylation was confirmed in cells with PKCδ catalytic domain mutants and by an RNAi method. Mechanistic studies revealed that IRS-1 with Ala and Glu point mutations at Ser24 impaired phosphatidylinositol-4,5-bisphosphate binding. In summary, our data are consistent with the hypothesis that Ser24 is a negative regulatory phosphorylation site in IRS-1

  7. Identification of Insulin-Like Growth Factor-I Receptor (IGF-IR) Gene Promoter-Binding Proteins in Estrogen Receptor (ER)-Positive and ER-Depleted Breast Cancer Cells

    International Nuclear Information System (INIS)

    Sarfstein, Rive; Belfiore, Antonino; Werner, Haim

    2010-01-01

    The insulin-like growth factor I receptor (IGF-IR) has been implicated in the etiology of breast cancer. Overexpression of the IGF-IR gene is a typical feature of most primary breast cancers, whereas low IGF-IR levels are seen at advanced stages. Hence, evaluation of IGF-IR levels might be important for assessing prognosis. In the present study, we employed a proteomic approach based on DNA affinity chromatography followed either by mass spectroscopy (MS) or Western blot analysis to identify transcription factors that may associate with the IGF-IR promoter in estrogen receptor (ER)-positive and ER-depleted breast cancer cells. A biotinylated IGF-IR promoter fragment was bound to streptavidin magnetic beads and incubated with nuclear extracts of breast cancer cells. IGF-IR promoter-binding proteins were eluted with high salt and analyzed by MS and Western blots. Among the proteins that were found to bind to the IGF-IR promoter we identified zinc finger transcription factors Sp1 and KLF6, ER-α, p53, c-jun, and poly (ADP-ribosylation) polymerase. Furthermore, chromatin immune-precipitation (ChIP) analysis confirmed the direct in vivo binding of some of these transcription factors to IGF-IR promoter DNA. The functional relevance of binding data was assessed by cotransfection experiments with specific expression vectors along with an IGF-IR promoter reporter. In summary, we identified nuclear proteins that are potentially responsible for the differential expression of the IGF-IR gene in ER-positive and ER-depleted breast cancer cells

  8. Identification of Insulin-Like Growth Factor-I Receptor (IGF-IR) Gene Promoter-Binding Proteins in Estrogen Receptor (ER)-Positive and ER-Depleted Breast Cancer Cells

    Energy Technology Data Exchange (ETDEWEB)

    Sarfstein, Rive [Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978 (Israel); Belfiore, Antonino [Department of Clinical and Experimental Medicine, University Magna Graecia of Catanzaro, Catanzaro 88100 (Italy); Werner, Haim, E-mail: hwerner@post.tau.ac.il [Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978 (Israel)

    2010-03-25

    The insulin-like growth factor I receptor (IGF-IR) has been implicated in the etiology of breast cancer. Overexpression of the IGF-IR gene is a typical feature of most primary breast cancers, whereas low IGF-IR levels are seen at advanced stages. Hence, evaluation of IGF-IR levels might be important for assessing prognosis. In the present study, we employed a proteomic approach based on DNA affinity chromatography followed either by mass spectroscopy (MS) or Western blot analysis to identify transcription factors that may associate with the IGF-IR promoter in estrogen receptor (ER)-positive and ER-depleted breast cancer cells. A biotinylated IGF-IR promoter fragment was bound to streptavidin magnetic beads and incubated with nuclear extracts of breast cancer cells. IGF-IR promoter-binding proteins were eluted with high salt and analyzed by MS and Western blots. Among the proteins that were found to bind to the IGF-IR promoter we identified zinc finger transcription factors Sp1 and KLF6, ER-α, p53, c-jun, and poly (ADP-ribosylation) polymerase. Furthermore, chromatin immune-precipitation (ChIP) analysis confirmed the direct in vivo binding of some of these transcription factors to IGF-IR promoter DNA. The functional relevance of binding data was assessed by cotransfection experiments with specific expression vectors along with an IGF-IR promoter reporter. In summary, we identified nuclear proteins that are potentially responsible for the differential expression of the IGF-IR gene in ER-positive and ER-depleted breast cancer cells.

  9. miR-598 acts as a tumor suppressor in human gastric cancer by targeting IGF-1R.

    Science.gov (United States)

    Liu, Na; Yang, Hua; Wang, Hong

    2018-01-01

    In recent years, the aberrant expression of miR-598 in tumorigenesis has been demonstrated, as well as the fact that the IGF-1R pathway is also involved in the development of human gastric cancer (GC). The present study aimed to investigate the molecular mechanisms underlying miR-598-regulated IGF-1R expression in human GC. We analyzed the expression of miR-598 and IGF-1R in GC samples and cells, and evaluated the clinical significance of miR-598 and IGF-1R in GC patients. Furthermore, in vitro and in vivo assays were used to investigate the molecular mechanisms of miR-598 and IGF-1R. miR-598 expression was frequently downregulated in GC tissues and cells, and significantly correlated with poor prognosis, vascular invasion, TNM stage, and lymph node metastases as well as IGF-1R expression. The overexpression of miR-598 obviously inhibited cell proliferation, migration, invasion, and induced cell cycle arrest in the G1/S phase, and increased the apoptosis of GC cells. The overexpression of miR-598 also significantly inhibited ERK1/2 and Akt phosphorylation level. In vivo assay validated the inhibitory effect of miR-598 on tumor growth. Further studies showed that miR-598 inhibited IGF-1R protein expression by directly targeting its 3'-UTR. Besides, over-expression of IGF-1R reversed the inhibitory effects of miR-598, while suppression of IGF-1R expression showed inverse effects. miR-598 suppresses GC cell proliferation, migration and invasion by directly targeting IGF-1R expression. Thus, miR-598 may be a useful target for GC patients.

  10. Combinational Therapy Enhances the Effects of Anti-IGF-1R mAb Figitumumab to Target Small Cell Lung Cancer.

    Directory of Open Access Journals (Sweden)

    Hongxin Cao

    Full Text Available Small cell lung cancer (SCLC is a recalcitrant malignancy with distinct biologic properties. Antibody targeting therapy has been actively investigated as a new drug modality.We tested the expression of IGF-1R and calculated the survival in 61 SCLC patients. We also evaluated the anti-tumor effects of anti-IGF-1R monoclonal antibody Figitumumab (CP on SCLC, and tried two drug combinations to improve CP therapy.Our clinical data suggested that high IGF-1R expression was correlated with low SCLC patient survival. We then demonstrated the effect of CP was likely through IGF-1R blockage and down-regulation without IGF-1R auto-phosphorylation and PI3K/AKT activation. However, we observed elevated MEK/ERK activation upon CP treatment in SCLC cells, and this MEK/ERK activation was enhanced by ß-arrestin1 knockdown while attenuated by ß-arrestin2 knockdown. We found both MEK/ERK inhibitor and metformin could enhance CP treatment in SCLC cells. We further illustrated the additive effect of metformin was likely through promoting further IGF-1R down-regulation.Our results highlighted the potential of anti-IGF-1R therapy and the adjuvant therapy strategy with either MEK/ERK inhibitor or metformin to target SCLC, warranting further studies.

  11. Differential effects of casein versus whey on fasting plasma levels of insulin, IGF-1 and IGF-1/IGFBP-3

    DEFF Research Database (Denmark)

    Hoppe, Camilla; Mølgaard, Christian; Dalum, Cathrine

    2009-01-01

    to the identification of which components in milk that stimulate growth, we have performed an intervention study with 57 eight-year-old boys in which we examined the effects of the two major milk protein fractions, whey and casein, and milk minerals (Ca and P) in a 2x2 factorial design on IGFs and glucose......–insulin metabolism. The amounts of whey and casein were identical to the content in 1.5 l skim milk. The amounts of Ca and P were similar to 1.5 l skim milk in the high-mineral drinks, whereas the amounts of Ca and P were reduced in the low-mineral drinks. Results: There were no interactions between milk mineral...... groups (high, low) and milk protein groups (whey, casein). Serum IGF-1 increased by 15% (P...

  12. Serum IGF-1 affects skeletal acquisition in a temporal and compartment-specific manner.

    Directory of Open Access Journals (Sweden)

    Hayden-William Courtland

    2011-03-01

    Full Text Available Insulin-like growth factor-1 (IGF-1 plays a critical role in the development of the growing skeleton by establishing both longitudinal and transverse bone accrual. IGF-1 has also been implicated in the maintenance of bone mass during late adulthood and aging, as decreases in serum IGF-1 levels appear to correlate with decreases in bone mineral density (BMD. Although informative, mouse models to date have been unable to separate the temporal effects of IGF-1 depletion on skeletal development. To address this problem, we performed a skeletal characterization of the inducible LID mouse (iLID, in which serum IGF-1 levels are depleted at selected ages. We found that depletion of serum IGF-1 in male iLID mice prior to adulthood (4 weeks decreased trabecular bone architecture and significantly reduced transverse cortical bone properties (Ct.Ar, Ct.Th by 16 weeks (adulthood. Likewise, depletion of serum IGF-1 in iLID males at 8 weeks of age, resulted in significantly reduced transverse cortical bone properties (Ct.Ar, Ct.Th by 32 weeks (late adulthood, but had no effect on trabecular bone architecture. In contrast, depletion of serum IGF-1 after peak bone acquisition (at 16 weeks resulted in enhancement of trabecular bone architecture, but no significant changes in cortical bone properties by 32 weeks as compared to controls. These results indicate that while serum IGF-1 is essential for bone accrual during the postnatal growth phase, depletion of IGF-1 after peak bone acquisition (16 weeks is compartment-specific and does not have a detrimental effect on cortical bone mass in the older adult mouse.

  13. The IGF system during growth and differentiation of the mouse

    NARCIS (Netherlands)

    M. van Kleffens (Marjolein)

    1999-01-01

    textabstractThe insulin-like growth factors (IGFs) were first discovered in 1957 by Salmon and Daughaday (1957). They found that in vivo administration of growth hormone (GH) induced a serum factor capable of stimulating sulfate uptake in cartilage. In 1972 this 'sulfation factor' was renamed

  14. Insulin-like growth factor I has independent effects on bone matrix formation and cell replication

    International Nuclear Information System (INIS)

    Hock, J.M.; Centrella, M.; Canalis, E.

    1988-01-01

    The effects of insulin-like growth factor-I (IGF-I) and insulin on bone matrix synthesis and bone cell replication were studied in cultured 21-day-old fetal rat calvariae. Histomorphometry techniques were developed to measure the incorporation of [2,3- 3 H]proline and [methyl- 3 H]thymidine into bone matrix and bone cell nuclei, respectively, using autoradiographs of sagittal sections of calvariae cultured with IGF-I, insulin, or vehicle for up to 96 h. To confirm an effect on bone formation, IGF-I was also studied for its effects on [ 3 H]proline incorporation into collagenase-digestible protein (CDP) and noncollagen protein and on [ 3 H]thymidine incorporation into acid-precipitable material (DNA). IGF-I at 10(-9)-10(-7) M significantly increased the rate of bone matrix apposition and CDP after 24 h by 45-50% and increased cell labeling by 8-fold in the osteoprogenitor cell zone, by 4-fold in the osteoblast cell zone, and by 2-fold in the periosteal fibroblast zone. Insulin at 10(-9)-10(-6) M also increased matrix apposition rate and CDP by 40-50%, but increased cell labeling by 2-fold only at a concentration of 10(-7) M or higher and then only in the osteoprogenitor cell zone. When hydroxyurea was added to IGF-I-treated bones, the effects of IGF-I on DNA synthesis were abolished, but the increase in bone matrix apposition induced by IGF-I was only partly diminished. In conclusion, IGF-I stimulates matrix synthesis in calvariae, an effect that is partly, although not completely, dependent on its stimulatory effect on DNA synthesis

  15. Rab11 is phosphorylated by classical and novel protein kinase C isoenzymes upon sustained phorbol ester activation.

    Science.gov (United States)

    Pavarotti, Martín; Capmany, Anahí; Vitale, Nicolas; Colombo, María Isabel; Damiani, María Teresa

    2012-02-01

    Rab11 is a small GTPase that controls diverse intracellular trafficking pathways. However, the molecular machinery that regulates the participation of Rab11 in those different transport events is poorly understood. In resting cells, Rab11 localizes at the endocytic recycling compartment (ERC), whereas the different protein kinase C (PKC) isoforms display a cytosolic distribution. Sustained phorbol ester stimulation induces the translocation of the classical PKCα and PKCβII isoenzymes to the ERC enriched in Rab11, and results in transferrin recycling inhibition. In contrast, novel PKCε and atypical PKCζ isoenzymes neither redistribute to the perinucleus nor modify transferrin recycling transport after phorbol ester stimulation. Although several Rabs have been shown to be phosphorylated, there is to date no evidence indicating Rab11 as a kinase substrate. In this report, we show that Rab11 appears phosphorylated in vivo in phorbol ester-stimulated cells. A bioinformatic analysis of Rab11 allowed us to identify several high-probability Ser/Thr kinase phosphorylation sites. Our results demonstrate that classical PKC (PKCα and PKCβII but not PKCβI) directly phosphorylate Rab11 in vitro. In addition, novel PKCε and PKCη but not PKCδ isoenzymes also phosphorylate Rab11. Mass spectrometry analysis revealed that Ser 177 is the Rab11 residue to be phosphorylated in vitro by either PKCβII or PKCε. In agreement, the phosphomimetic mutant, Rab11 S177D, retains transferrin at the ERC in the absence of phorbol-12-myristate-13-acetate stimulus. This report shows for the first time that Rab11 is differentially phosphorylated by distinct PKC isoenzymes and that this post-translational modification might be a regulatory mechanism of intracellular trafficking. Copyright © 2012 Soçiété Francaise des Microscopies and Société de Biologie Cellulaire de France.

  16. Histone H1 phosphorylation is associated with transcription by RNA polymerases I and II

    Science.gov (United States)

    Zheng, Yupeng; John, Sam; Pesavento, James J.; Schultz-Norton, Jennifer R.; Schiltz, R. Louis; Baek, Sonjoon; Nardulli, Ann M.; Hager, Gordon L.; Kelleher, Neil L.

    2010-01-01

    Histone H1 phosphorylation affects chromatin condensation and function, but little is known about how specific phosphorylations impact the function of H1 variants in higher eukaryotes. In this study, we show that specific sites in H1.2 and H1.4 of human cells are phosphorylated only during mitosis or during both mitosis and interphase. Antisera generated to individual H1.2/H1.4 interphase phosphorylations reveal that they are distributed throughout nuclei and enriched in nucleoli. Moreover, interphase phosphorylated H1.4 is enriched at active 45S preribosomal RNA gene promoters and is rapidly induced at steroid hormone response elements by hormone treatment. Our results imply that site-specific interphase H1 phosphorylation facilitates transcription by RNA polymerases I and II and has an unanticipated function in ribosome biogenesis and control of cell growth. Differences in the numbers, structure, and locations of interphase phosphorylation sites may contribute to the functional diversity of H1 variants. PMID:20439994

  17. Resveratrol suppresses IGF-1 induced human colon cancer cell proliferation and elevates apoptosis via suppression of IGF-1R/Wnt and activation of p53 signaling pathways

    Directory of Open Access Journals (Sweden)

    Radhakrishnan Sridhar

    2010-05-01

    Full Text Available Abstract Background Obesity is a global phenomenon and is associated with various types of cancer, including colon cancer. There is a growing interest for safe and effective bioactive compounds that suppress the risk for obesity-promoted colon cancer. Resveratrol (trans-3, 4', 5,-trihydroxystilbene, a stilbenoid found in the skin of red grapes and peanuts suppresses many types of cancers by regulating cell proliferation and apoptosis through a variety of mechanisms, however, resveratrol effects on obesity-promoted colon cancer are not clearly established. Methods We investigated the anti-proliferative effects of resveratrol on HT-29 and SW480 human colon cancer cells in the presence and absence of insulin like growth factor-1 (IGF-1; elevated during obesity and elucidated the mechanisms of action using IGF-1R siRNA in HT-29 cells which represents advanced colon carcinogenesis. Results Resveratrol (100-150 μM exhibited anti-proliferative properties in HT-29 cells even after IGF-1 exposure by arresting G0/G1-S phase cell cycle progression through p27 stimulation and cyclin D1 suppression. Treatment with resveratrol suppressed IGF-1R protein levels and concurrently attenuated the downstream Akt/Wnt signaling pathways that play a critical role in cell proliferation. Targeted suppression of IGF-1R using IGF-1R siRNA also affected these signaling pathways in a similar manner. Resveratrol treatment induced apoptosis by activating tumor suppressor p53 protein, whereas IGF-1R siRNA treatment did not affect apoptosis. Our data suggests that resveratrol not only suppresses cell proliferation by inhibiting IGF-1R and its downstream signaling pathways similar to that of IGF-1R siRNA but also enhances apoptosis via activation of the p53 pathway. Conclusions For the first time, we report that resveratrol suppresses colon cancer cell proliferation and elevates apoptosis even in the presence of IGF-1 via suppression of IGF-1R/Akt/Wnt signaling pathways and

  18. Resveratrol suppresses IGF-1 induced human colon cancer cell proliferation and elevates apoptosis via suppression of IGF-1R/Wnt and activation of p53 signaling pathways

    International Nuclear Information System (INIS)

    Vanamala, Jairam; Reddivari, Lavanya; Radhakrishnan, Sridhar; Tarver, Chris

    2010-01-01

    Obesity is a global phenomenon and is associated with various types of cancer, including colon cancer. There is a growing interest for safe and effective bioactive compounds that suppress the risk for obesity-promoted colon cancer. Resveratrol (trans-3, 4', 5,-trihydroxystilbene), a stilbenoid found in the skin of red grapes and peanuts suppresses many types of cancers by regulating cell proliferation and apoptosis through a variety of mechanisms, however, resveratrol effects on obesity-promoted colon cancer are not clearly established. We investigated the anti-proliferative effects of resveratrol on HT-29 and SW480 human colon cancer cells in the presence and absence of insulin like growth factor-1 (IGF-1; elevated during obesity) and elucidated the mechanisms of action using IGF-1R siRNA in HT-29 cells which represents advanced colon carcinogenesis. Resveratrol (100-150 μM) exhibited anti-proliferative properties in HT-29 cells even after IGF-1 exposure by arresting G 0 /G 1 -S phase cell cycle progression through p27 stimulation and cyclin D1 suppression. Treatment with resveratrol suppressed IGF-1R protein levels and concurrently attenuated the downstream Akt/Wnt signaling pathways that play a critical role in cell proliferation. Targeted suppression of IGF-1R using IGF-1R siRNA also affected these signaling pathways in a similar manner. Resveratrol treatment induced apoptosis by activating tumor suppressor p53 protein, whereas IGF-1R siRNA treatment did not affect apoptosis. Our data suggests that resveratrol not only suppresses cell proliferation by inhibiting IGF-1R and its downstream signaling pathways similar to that of IGF-1R siRNA but also enhances apoptosis via activation of the p53 pathway. For the first time, we report that resveratrol suppresses colon cancer cell proliferation and elevates apoptosis even in the presence of IGF-1 via suppression of IGF-1R/Akt/Wnt signaling pathways and activation of p53, suggesting its potential role as a

  19. Divergent frequencies of IGF-I receptor-expressing blood lymphocytes in monozygotic twin pairs discordant for Graves' disease: evidence for a phenotypic signature ascribable to nongenetic factors

    DEFF Research Database (Denmark)

    Douglas, Raymond S; Brix, Thomas H; Hwang, Catherine J

    2009-01-01

    CONTEXT: Graves' disease (GD) is an autoimmune process of the thyroid and orbital connective tissues. The fraction of T and B cells expressing IGF-I receptor (IGF-IR) is increased in GD. It is a potentially important autoantigen in GD. Susceptibility to GD arises from both genetic and acquired...

  20. Co-induction of hepatic IGF-I and progranulin mRNA by growth hormone in tilapia, Oreochromis mossambiccus

    Science.gov (United States)

    Like IGF-I, progranulin (pgrn) is a growth factor involved in tumorigenesis and wound healing. We report here the identification and characterization of pgrn cDNA in tilapia and the regulation of its expression by growth hormone(GH). The tilapia pgrn cDNA was cloned by RT-PCR ampliWcation, using g...