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Sample records for insulin receptor gene

  1. Intracellular insulin-receptor dissociation and segregation in a rat fibroblast cell line transfected with a human insulin receptor gene

    International Nuclear Information System (INIS)

    Levy, J.R.; Olefsky, J.M.

    1988-01-01

    The cellular processing of insulin and insulin receptors was studied using a rat fibroblast cell line that had been transfected with a normal human insulin receptor gene, expressing approximately 500 times the normal number of native fibroblasts insulin receptors. These cells bind and internalize insulin normally. Biochemically assays based on the selective precipitation by polyethylene glycol of intact insulin-receptor complexes but not of free intracellular insulin were developed to study the time course of intracellular insulin-receptor dissociation. Fibroblasts were incubated with radiolabeled insulin at 4 0 C, and internalization of insulin-receptor complexes was initiated by warming the cells to 37 0 C. Within 2 min, 90% of the internalized radioactivity was composed of intact insulin-receptor complexes. The dissociation of insulin from internalized insulin-receptor complexes was markedly inhibited by monensin and chloroquine. Furthermore, chloroquine markedly increased the number of cross-linkable intracellular insulin-receptor complexes, as analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis autoradiography. These findings suggest that acidification of intracellular vesicles is responsible for insulin-receptor dissociation. Physical segregation of dissociated intracellular insulin from its receptor was monitored. The results are consistent with the view that segregation of insulin and receptor occurs 5-10 min after initiation of dissociation. These studies demonstrate the intracellular itinerary of insulin-receptor complexes, including internalization, dissociation of insulin from the internalized receptor within an acidified compartment, segregation of insulin from the receptor, and subsequent ligand degradation

  2. Insulin receptors

    International Nuclear Information System (INIS)

    Kahn, C.R.; Harrison, L.C.

    1988-01-01

    This book contains the proceedings on insulin receptors. Part A: Methods for the study of structure and function. Topics covered include: Method for purification and labeling of insulin receptors, the insulin receptor kinase, and insulin receptors on special tissues

  3. Evolution of the vertebrate insulin receptor substrate (Irs) gene family.

    Science.gov (United States)

    Al-Salam, Ahmad; Irwin, David M

    2017-06-23

    Insulin receptor substrate (Irs) proteins are essential for insulin signaling as they allow downstream effectors to dock with, and be activated by, the insulin receptor. A family of four Irs proteins have been identified in mice, however the gene for one of these, IRS3, has been pseudogenized in humans. While it is known that the Irs gene family originated in vertebrates, it is not known when it originated and which members are most closely related to each other. A better understanding of the evolution of Irs genes and proteins should provide insight into the regulation of metabolism by insulin. Multiple genes for Irs proteins were identified in a wide variety of vertebrate species. Phylogenetic and genomic neighborhood analyses indicate that this gene family originated very early in vertebrae evolution. Most Irs genes were duplicated and retained in fish after the fish-specific genome duplication. Irs genes have been lost of various lineages, including Irs3 in primates and birds and Irs1 in most fish. Irs3 and Irs4 experienced an episode of more rapid protein sequence evolution on the ancestral mammalian lineage. Comparisons of the conservation of the proteins sequences among Irs paralogs show that domains involved in binding to the plasma membrane and insulin receptors are most strongly conserved, while divergence has occurred in sequences involved in interacting with downstream effector proteins. The Irs gene family originated very early in vertebrate evolution, likely through genome duplications, and in parallel with duplications of other components of the insulin signaling pathway, including insulin and the insulin receptor. While the N-terminal sequences of these proteins are conserved among the paralogs, changes in the C-terminal sequences likely allowed changes in biological function.

  4. [Severe type A insulin resistance syndrome due to a mutation in the insulin receptor gene].

    Science.gov (United States)

    Ros, P; Colino-Alcol, E; Grasso, V; Barbetti, F; Argente, J

    2015-01-01

    Insulin resistance syndromes without lipodystrophy are an infrequent and heterogeneous group of disorders with variable clinical phenotypes, associated with hyperglycemia and hyperinsulinemia. The three conditions related to mutations in the insulin receptor gene are leprechaunism or Donohue syndrome, Rabson-Mendenhall syndrome, and Type A syndrome. A case is presented on a patient diagnosed with type A insulin resistance, defined by the triad of extreme insulin resistance, acanthosis nigricans, and hyperandrogenism, carrying a heterozygous mutation in exon 19 of the insulin receptor gene coding for its tyrosine kinase domain that is crucial for the catalytic activity of the receptor. The molecular basis of the syndrome is reviewed, focusing on the structure-function relationships of the insulin receptor, knowing that the criteria for survival are linked to residual insulin receptor function. It is also pointed out that, although type A insulin resistance appears to represent a somewhat less severe condition, these patients have a high morbidity and their treatment is still unsatisfactory. Copyright © 2014 Asociación Española de Pediatría. Published by Elsevier Espana. All rights reserved.

  5. Receptor-like protein-tyrosine phosphatase alpha specifically inhibits insulin-increased prolactin gene expression

    DEFF Research Database (Denmark)

    Jacob, K K; Sap, J; Stanley, F M

    1998-01-01

    A physiologically relevant response to insulin, stimulation of prolactin promoter activity in GH4 pituitary cells, was used as an assay to study the specificity of protein-tyrosine phosphatase function. Receptor-like protein-tyrosine phosphatase alpha (RPTPalpha) blocks the effect of insulin...... is specific by two criteria. A number of potential RPTPalpha targets were ruled out by finding (a) that they are not affected or (b) that they are not on the pathway to insulin-increased prolactin-CAT activity. The negative effect of RPTPalpha on insulin activation of the prolactin promoter is not due...... to reduced phosphorylation or kinase activity of the insulin receptor or to reduced phosphorylation of insulin receptor substrate-1 or Shc. Inhibitor studies suggest that insulin-increased prolactin gene expression is mediated by a Ras-like GTPase but is not mitogen-activated protein kinase dependent...

  6. Fatty acid represses insulin receptor gene expression by impairing HMGA1 through protein kinase Cε

    International Nuclear Information System (INIS)

    Dey, Debleena; Bhattacharya, Anirban; Roy, SibSankar; Bhattacharya, Samir

    2007-01-01

    It is known that free fatty acid (FFA) contributes to the development of insulin resistance and type2 diabetes. However, the underlying mechanism in FFA-induced insulin resistance is still unclear. In the present investigation we have demonstrated that palmitate significantly (p < 0.001) inhibited insulin-stimulated phosphorylation of PDK1, the key insulin signaling molecule. Consequently, PDK1 phosphorylation of plasma membrane bound PKCε was also inhibited. Surprisingly, phosphorylation of cytosolic PKCε was greatly stimulated by palmitate; this was then translocated to the nuclear region and associated with the inhibition of insulin receptor (IR) gene transcription. A PKCε translocation inhibitor peptide, εV1, suppressed this inhibitory effect of palmitate, suggesting requirement of phospho-PKCε migration to implement palmitate effect. Experimental evidences indicate that phospho-PKCε adversely affected HMGA1. Since HMGA1 regulates IR promoter activity, expression of IR gene was impaired causing reduction of IR on cell surface and that compromises with insulin sensitivity

  7. Knockout of Vasohibin-1 Gene in Mice Results in Healthy Longevity with Reduced Expression of Insulin Receptor, Insulin Receptor Substrate 1, and Insulin Receptor Substrate 2 in Their White Adipose Tissue

    Directory of Open Access Journals (Sweden)

    Eichi Takeda

    2017-01-01

    Full Text Available Vasohibin-1 (Vash1, originally isolated as an endothelium-derived angiogenesis inhibitor, has a characteristic of promoting stress tolerance in endothelial cells (ECs. We therefore speculated that the lack of the vash1 gene would result in a short lifespan. However, to our surprise, vash1−/− mice lived significantly longer with a milder senescence phenotype than wild-type (WT mice. We sought the cause of this healthy longevity and found that vash1−/− mice exhibited mild insulin resistance along with reduced expression of the insulin receptor (insr, insulin receptor substrate 1 (irs-1, and insulin receptor substrate 2 (irs-2 in their white adipose tissue (WAT but not in their liver or skeletal muscle. The expression of vash1 dominated in the WAT among those 3 organs. Importantly, vash1−/− mice did not develop diabetes even when fed a high-fat diet. These results indicate that the expression of vash1 was required for the normal insulin sensitivity of the WAT and that the target molecules for this activity were insr, irs1, and irs2. The lack of vash1 caused mild insulin resistance without the outbreak of overt diabetes and might contribute to healthy longevity.

  8. Partial rescue of in vivo insulin signalling in skeletal muscle by impaired insulin clearance in heterozygous carriers of a mutation in the insulin receptor gene

    DEFF Research Database (Denmark)

    Højlund, K.; Wojtaszewski, Jørgen; Birk, Jesper Bratz

    2006-01-01

    AIMS/HYPOTHESIS: Recently we reported the coexistence of postprandial hypoglycaemia and moderate insulin resistance in heterozygous carriers of the Arg1174Gln mutation in the insulin receptor gene (INSR). Controlled studies of in vivo insulin signalling in humans with mutant INSR are unavailable,...

  9. Vitamin D receptor gene polymorphisms, dietary promotion of insulin resistance, and colon and rectal cancer.

    Science.gov (United States)

    Murtaugh, Maureen A; Sweeney, Carol; Ma, Khe-Ni; Potter, John D; Caan, Bette J; Wolff, Roger K; Slattery, Martha L

    2006-01-01

    Modifiable risk factors in colorectal cancer etiology and their interactions with genetic susceptibility are of particular interest. Functional vitamin D receptor (VDR) gene polymorphisms may influence carcinogenesis through modification of cell growth, protection from oxidative stress, cell-cell matrix effects, or insulin and insulin-like growth factor pathways. We investigated interactions between foods (dairy products, red and processed meat, and whole and refined grains) and dietary patterns (sucrose-to-fiber ratio and glycemic index) associated with insulin resistance with the FokI polymorphism of the VDR gene and colon and rectal cancer risk. Data (diet, anthropometrics, and lifestyle) and DNA came from case-control studies of colon (1,698 cases and 1,861 controls) and rectal cancer (752 cases and 960 controls) in northern California, Utah, and the Twin Cities metropolitan area, Minnesota (colon cancer study only). Unconditional logistic regression models were adjusted for smoking, race, sex, age, body mass index, physical activity, energy intake, dietary fiber, and calcium. The lowest colon cancer risk was observed with the Ff/ff FokI genotypes and a low sucrose-to-fiber ratio. Rectal cancer risk decreased with greater consumption of dairy products and increased with red or processed meat consumption and the FF genotype. Modifiable dietary risk factors may be differentially important among individuals by VDR genotype and may act through the insulin pathway to affect colon cancer risk and through fat, calcium, or other means to influence rectal cancer risk.

  10. 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...

  11. Metformin and insulin receptors

    International Nuclear Information System (INIS)

    Vigneri, R.; Gullo, D.; Pezzino, V.

    1984-01-01

    The authors evaluated the effect of metformin (N,N-dimethylbiguanide), a biguanide known to be less toxic than phenformin, on insulin binding to its receptors, both in vitro and in vivo. Specific 125 I-insulin binding to cultured IM-9 human lymphocytes and MCF-7 human breast cancer cells was determined after preincubation with metformin. Specific 125 I-insulin binding to circulating monocytes was also evaluated in six controls, eight obese subjects, and six obese type II diabetic patients before and after a short-term treatment with metformin. Plasma insulin levels and blood glucose were also measured on both occasions. Metformin significantly increased insulin binding in vitro to both IM-9 lymphocytes and MCF-7 cells; the maximum increment was 47.1% and 38.0%, respectively. Metformin treatment significantly increased insulin binding in vivo to monocytes of obese subjects and diabetic patients. Scatchard analysis indicated that the increased binding was mainly due to an increase in receptor capacity. Insulin binding to monocytes of normal controls was unchanged after metformin as were insulin levels in all groups; blood glucose was significantly reduced after metformin only in diabetic patients. These data indicate that metformin increases insulin binding to its receptors in vitro and in vivo. The effect in vivo is observed in obese subjects and in obese type II diabetic patients, paralleling the clinical effectiveness of this antidiabetic agent, and is not due to receptor regulation by circulating insulin, since no variation in insulin levels was recorded

  12. Expression of the growth hormone receptor gene in insulin producing cells

    DEFF Research Database (Denmark)

    Møldrup, Annette; Billestrup, N; Nielsen, Jens Høiriis

    1990-01-01

    Growth hormone (GH) plays a dual role in glucose homeostasis. On the one hand, it exerts an insulin antagonistic effect on the peripheral tissue, on the other hand, it stimulates insulin biosynthesis and beta-cell proliferation. The expression of GH-receptors on the rat insulinoma cell line RIN-5...

  13. A novel syndrome of autosomal-dominant hyperinsulinemic hypoglycemia linked to a mutation in the human insulin receptor gene

    DEFF Research Database (Denmark)

    Højlund, Kurt; Hansen, Torben; Lajer, Maria

    2004-01-01

    a missense mutation (Arg1174Gln) in the tyrosine kinase domain of the insulin receptor gene that cosegregated with the disease phenotype (logarithm of odds [LOD] score 3.21). In conclusion, we report a novel syndrome of autosomal-dominant hyperinsulinemic hypoglycemia. The findings demonstrate...

  14. Alternative splicing, gene localization, and binding of SH2-B to the insulin receptor kinase domain

    OpenAIRE

    Nelms, Keats; O'Neill, Thomas J.; Li, Shiqing; Hubbard, Stevan R.; Gustafson, Thomas A.; Paul, William E.

    1999-01-01

    . The SH2-B protein is an SH2-domain-containing molecule that interacts with a number of phosphorylated kinase and receptor molecules including the insulin receptor. Two isoforms of the SH2-B have been identified and have been proposed to arise through alternate splicing. Here we have identified a third isoform of the SH2-B protein, SH2-Bγ, that interacts specifically with the insulin receptor. This interaction required phosphorylation of residue Y1146 in the triple tyrosine motif within the ...

  15. Effects of insulin and exercise training on FGF21, its receptors and target genes in obesity and type 2 diabetes

    DEFF Research Database (Denmark)

    Sørensen, Rikke Kruse; Vienberg, Sara Gry; Vind, Birgitte F

    2017-01-01

    obesity with and without type 2 diabetes led to reduced expression of KLB, but increased FGFR1c expression. However, the expression of most FGF21 target genes was unaltered except for reduced CIDEA expression in individuals with type 2 diabetes. CONCLUSIONS....../INTERPRETATION: Insulin-induced expression of muscle FGF21 correlates strongly with a rise in serum FGF21, and this response appears intact in overweight/obesity and type 2 diabetes. FGF21 resistance may involve reduced KLB expression in WAT. However, increased FGFR1c expression or other mechanisms seem to ensure...... that insulin and exercise increase FGF21 in plasma. Obesity and type 2 diabetes are potentially FGF21-resistant states, but to what extent FGF21 responses to insulin and exercise training are preserved, and whether FGF21, its receptors and target genes are altered, remains to be established. METHODS...

  16. Evaluated the Up –regulation in Gene ‎Expression of Hepatic Insulin Gene and ‎Hepatic Insulin Receptor Gene in Type 1 ‎Diabetic Rats Treated with Cuscuta chinesis ‎Lam.‎

    Directory of Open Access Journals (Sweden)

    Fadia ‎ H. Al-Sultany

    2018-02-01

    Full Text Available         This research was conducted to study the hypoglycemic activity of C. chinesis Lam on type 1 diabetic disease and investigate the  molecular and histological mechanism of  its action .many parameters was investigated , Fasting blood glucose (FBG, Fasting serum insulin,Hepatic Insulin Gene Expression, pancreas Insulin Gene Expression ,Hepatic Insulin  Receptors Gene expression  and histological sections of pancrease and liver.54 Rattus rattus male rats weighting(180 -200g were divided into 3 groups: A normal control daily administrated with Dw, B Diabetic control daily administrated with Dw  and C  diabetic group daily administrated with 400 mg/Kg body weight of C. chinesis  Lam. methanolic extract, each group consisted of  18 rats and further divided into (3 sub- groups 1 ,2  and 3. According to the period of administration  30, 60 and  90 days respectively. The results showing  the daily administration of 400 mg/Kg body weight of C. chinesis  Lam. methanolic extract for 60 day causing significance  decrease  in FBG and In the other hand each of fasting serum insulin, hepatic Insulin gene expression,pancreas Insulin gene expression and hepatic Insulin receptor gene expression was increased in group C in compare to B group and return all studied parameters involving pancrease and liver texture to the normal state ,which were statically morphologically  not appeared any significant difference from A group .this study concluded that the daily administration type 1 diabetic rats with 400 mg/Kg body weight of C. chinesis  Lam. extract for 60 day was return  fasting serum insulin and FBG to normal value by  upregulated  the gene expression of hepatic INS Gene ,INSR gene , pancreas INS Gene ,regenerate pancreatic beta- cell and returnthe texture of both liver and pancrease to the normal state

  17. Energy expenditure, body composition and insulin response to glucose in male twins discordant for the Trp64Arg polymorphism of the β3-adrenergic receptor gene

    DEFF Research Database (Denmark)

    Højlund, Kurt; Christiansen, Christian; Bjørnsbo, K.S.

    2006-01-01

    AIM: The tryptophan to arginine change in position 64 (Trp64Arg) polymorphism of the beta3-adrenergic receptor (beta3AR) gene has been associated with an increased prevalence of obesity, insulin resistance and type 2 diabetes. In this, decreased rates of energy expenditure and impaired insulin...... and environmental background, the Trp64Arg polymorphism of the beta3AR gene is associated with lower fat mass, fasting insulin levels and an appropriate insulin response to glucose. Thus, heterozygosity for the Trp64Arg variant is unlikely to increase the risk of obesity, insulin resistance or type 2 diabetes....

  18. Dietary approaches to stop hypertension influence on insulin receptor substrate-1gene expression: A randomized controlled clinical trial

    Directory of Open Access Journals (Sweden)

    Marzieh Kafeshani

    2015-01-01

    Full Text Available Background: Insulin receptor substrate (IRS Type 1 is a main substrate for the insulin receptor, controls insulin signaling in skeletal muscle, adipose tissue, and the vascular, so it is an important candidate gene for insulin resistance (IR. We aimed to compare the effects of the Dietary Approaches to Stop Hypertension (DASH and Usual Dietary Advices (UDA on IRS1 gene expression in women at risk for cardiovascular disease. Materials and Methods: A randomized controlled clinical trial was performed in 44 women at risk for cardiovascular disease. Participants were randomly assigned to a UDA diet or the DASH diet. The DASH diet was rich in fruits, vegetables, whole grains, and low-fat dairy products and low in saturated fat, total fat, cholesterol, refined grains, and sweets, with a total of 2400 mg/day sodium. The UDA diet was a regular diet with healthy dietary advice. Gene expression was assessed by the real-time polymerase chain reaction at the first of study and after 12 weeks. Independent sample t-test and paired-samples t-test were used to compare means of all variables within and between two groups respectively. Results: IRS1 gene expression was increased in DASH group compared with UDA diet (P = 0.00. Weight and waist circumference decreased in DASH group significantly compared to the UDA group (P < 0.05 but the results between the two groups showed no significant difference. Conclusion: DASH diet increased IRS1 gene expression and probably has beneficial effects on IR risks.

  19. Disruption of growth hormone receptor gene causes diminished pancreatic islet size and increased insulin sensitivity in mice.

    Science.gov (United States)

    Liu, Jun-Li; Coschigano, Karen T; Robertson, Katie; Lipsett, Mark; Guo, Yubin; Kopchick, John J; Kumar, Ujendra; Liu, Ye Lauren

    2004-09-01

    Growth hormone, acting through its receptor (GHR), plays an important role in carbohydrate metabolism and in promoting postnatal growth. GHR gene-deficient (GHR(-/-)) mice exhibit severe growth retardation and proportionate dwarfism. To assess the physiological relevance of growth hormone actions, GHR(-/-) mice were used to investigate their phenotype in glucose metabolism and pancreatic islet function. Adult GHR(-/-) mice exhibited significant reductions in the levels of blood glucose and insulin, as well as insulin mRNA accumulation. Immunohistochemical analysis of pancreatic sections revealed normal distribution of the islets despite a significantly smaller size. The average size of the islets found in GHR(-/-) mice was only one-third of that in wild-type littermates. Total beta-cell mass was reduced 4.5-fold in GHR(-/-) mice, significantly more than their body size reduction. This reduction in pancreatic islet mass appears to be related to decreases in proliferation and cell growth. GHR(-/-) mice were different from the human Laron syndrome in serum insulin level, insulin responsiveness, and obesity. We conclude that growth hormone signaling is essential for maintaining pancreatic islet size, stimulating islet hormone production, and maintaining normal insulin sensitivity and glucose homeostasis.

  20. No association of the G972S polymorphism of the insulin receptor substrate-1 gene with polycystic ovary syndrome in lean PCOS women with biochemical hyperandrogenemia.

    Science.gov (United States)

    Marioli, Dimitra J; Koika, Vasiliki; Adonakis, George L; Saltamavros, Alexandros D; Karela, Anastasia; Armeni, Anastasia K; Tsapanos, Vasilios S; Decavalas, George O; Georgopoulos, Neoklis A

    2010-06-01

    The aim of the present study was to determine the prevalence and association of the G972S polymorphism of the insulin receptor substrate-1 gene (IRS-1 G972S SNP) with polycystic ovary syndrome (PCOS) and insulin resistance-related traits in a distinct phenotypic group of lean PCOS women with biochemical hyperandrogenemia, excluding obesity, which is considered to be an aggravating parameter of insulin resistance. The study included 162 women with PCOS and 122 regularly menstruating, ovulatory women as controls. Physical measurements included weight, height, fat-free mass, fat mass, systolic and diastolic blood pressure and resting heart rate. Biochemical parameters included the serum testosterone, free testosterone, androstenedione, total cholesterol, triglycerides, HDL and LDL cholesterol and glucose levels. Insulin resistance was assessed by determining fasting insulin levels, fasting glucose levels, the fasting glucose/insulin ratio, as well as the HOMA and QUICKI indexes. All DNA samples were genotyped by a PCR-restriction fragment length polymorphism (RLFP) assay. No association of the genotype frequencies of the G972S polymorphism in insulin receptor substrate-1 gene (IRS-1 G972S SNP) with PCOS phenotype and insulin resistance was detected. The G972S polymorphism of the IRS-1 gene should not be viewed as major contributor to the development of PCOS or as a causative variant for insulin resistance.

  1. Codon 972 polymorphism in the insulin receptor substrate-1 gene, obesity, and risk of noninsulin-dependent diabetes mellitus

    Energy Technology Data Exchange (ETDEWEB)

    Sigal, R.J.; Doria, A.; Warram, J.H.; Krolewski, A.S. [Joslin Diabetes Center, Boston, MA (United States)

    1996-04-01

    Because of the role of insulin receptor substrate-1 in insulin action, the insulin receptor substrate-1 gene is a candidate gene for noninsulin-dependent diabetes mellitus (NIDDM). Modest associations between NIDDM and a GGG-AGG single base substitution (corresponding to a glycine-arginine amino acid substitution) in codon 972 of the gene have been found, but none reached statistical significance. To examine further how large a proportion of NIDDM cases could be caused by the mutation, we performed a stratified analysis combining the results from the 6 earlier studies and those from our panel of 192 unrelated NIDDM subjects and 104 healthy controls. In addition, we looked for a possibility that the codon 972 mutation plays a role only in the presence of certain conditions. Genomic DNA samples obtained from NIDDM cases and healthy controls were genotyped using a PCR-restriction fragment length polymorphism protocol modified for genomic DNA. The GGG{r_arrow}AGG substitution was found in 5.7% of the diabetic subjects (11 of 192) and 6.9% of the controls (7 of 104). The difference between groups was not statistically significant, and it was not different from the results of other studies. The Mantel-Haenszel summary odds ratio across all studies was 1.49 (P < 0.05; 95% confidence intervals, 1.01-2.2). This summary odds ratio is consistent with a small proportion of NIDDM cases ({approximately}3%) being caused by the mutation. Exploratory subgroup analyses on our panel suggested a clustering of NIDDM, the codon 972 mutation, and overweight, raising the hypothesis that the mutation may predispose to NIDDM only in the presence of excess body weight. 9 refs., 2 tabs.

  2. Testosterone treatment increases androgen receptor and aromatase gene expression in myotubes from patients with PCOS and controls, but does not induce insulin resistance.

    Science.gov (United States)

    Eriksen, Mette Brandt; Glintborg, Dorte; Nielsen, Michael Friberg Bruun; Jakobsen, Marianne Antonius; Brusgaard, Klaus; Tan, Qihua; Gaster, Michael

    2014-09-05

    Polycystic ovary syndrome (PCOS) is associated with insulin resistance and increased risk of type 2 diabetes. Skeletal muscle is the major site of insulin mediated glucose disposal and the skeletal muscle tissue is capable to synthesize, convert and degrade androgens. Insulin sensitivity is conserved in cultured myotubes (in vitro) from patients with PCOS, but the effect of testosterone on this insulin sensitivity is unknown. We investigated the effect of 7days testosterone treatment (100nmol/l) on glucose transport and gene expression levels of hormone receptors and enzymes involved in the synthesis and conversion of testosterone (HSD17B1, HSD17B2, CYP19A1, SRD5A1-2, AR, ER-α, HSD17B6 and AKR1-3) in myotubes from ten patients with PCOS and ten matched controls. Testosterone treatment significantly increased aromatase and androgen receptor gene expression levels in patients and controls. Glucose transport in myotubes was comparable in patients with PCOS vs. controls and was unchanged by testosterone treatment (p=0.21 PCOS vs. controls). These results suggest that testosterone treatment of myotubes increases the aromatase and androgen receptor gene expression without affecting insulin sensitivity and if testosterone is implicated in muscular insulin resistance in PCOS, this is by and indirect mechanism. Copyright © 2014 Elsevier Inc. All rights reserved.

  3. Studies on insulin receptor, 2

    International Nuclear Information System (INIS)

    Sakai, Yukio

    1979-01-01

    The present study is to investigate an influence of starvation and high fat diet on insulin receptor of the plasma membrane by means of radioreceptor assay using 125 I-labelled insulin. Male guinea pigs of Hartley strain were employed for the starvation study, and 125 I-insulin binding capacity on the plasma membrane of the liver and kidney was determined at 24, 48 and 72 hours of the fast after the last meal. Male rats of Wistar strain were employed for the high fat study where the diet containing 35% of butter was fed ad libitum for 38 or 68 days. The animals were killed at the fast of 12 hours, and 125 I-insulin binding capacity on the plasma membrane of the liver was determined. The results obtained are summarized as follows: 1) An increase in 125 I-insulin binding capacity on the plasma membrane of the liver and kidney was observed by the starvation for 24 to 72 hours. 2) The mechanism of the increase by starvation was considered to be different by the organs; it was due to an increase in number of insulin receptor in the liver, and due to an increase in affinity of insulin receptor in the kidney. 3) In non-obese rats fed with high fat diet, the number of insulin receptor on the liver plasma membrane showed a decrease, and this observation clearly indicated that the decrease in number of the receptor did not depend on the obesity. 4) Obese rats also fed with high fat diet presented a decrease in number of insulin receptor without an elevation of insulin levels in the circulating blood. This indicated that at least in the obese rats fed with high fat diet, the decrease in number of the receptor was not due to hyperinsulinemia. (author)

  4. Experimental diabetes increases insulin-like growth factor I and II receptor concentration and gene expression in kidney

    International Nuclear Information System (INIS)

    Werner, H.; Shen-Orr, Z.; Stannard, B.; Burguera, B.; Roberts, C.T. Jr.; LeRoith, D.

    1990-01-01

    Insulinlike growth factor I (IGF-I) is a mitogenic hormone with important regulatory roles in growth and development. One of the target organs for IGF-I action is the kidney, which synthesizes abundant IGF-I receptors and IGF-I itself. To study the involvement of IGF-I and the IGF-I receptor in the development of nephropathy, one of the major complications of diabetes mellitus, we measured the expression of these genes in the kidney and in other tissues of the streptozocin-induced diabetic rat. The binding of 125I-labeled IGF-I to crude membranes was measured in the same tissues. We observed a 2.5-fold increase in the steady-state level of IGF-I-receptor mRNA in the diabetic kidney, which was accompanied by a 2.3-fold increase in IGF-I binding. In addition to this increase in IGF-I binding to the IGF-I receptor, there was also binding to a lower-molecular-weight material that may represent an IGF-binding protein. No change was detected in the level of IGF-I-peptide mRNA. Similarly, IGF-II-receptor mRNA levels and IGF-II binding were significantly increased in the diabetic kidney. IGF-I- and IGF-II-receptor mRNA levels and IGF-I and IGF-II binding returned to control values after insulin treatment. Because the IGF-I receptor is able to transduce mitogenic signals on activation of its tyrosine kinase domain, we hypothesize that, among other factors, high levels of receptor in the diabetic kidney may also be involved in the development of diabetic nephropathy. Increased IGF-II-receptor expression in the diabetic kidney may be important for the intracellular transport and packaging of lysosomal enzymes, although a role for this receptor in signal transduction cannot be excluded. Finally, the possible role of IGF-binding proteins requires further study

  5. Testosterone treatment increases androgen receptor and aromatase gene expression in myotubes from patients with PCOS and controls, but does not induce insulin resistance

    DEFF Research Database (Denmark)

    Eriksen, Mette Brandt; Glintborg, Dorte; Nielsen, Michael Friberg Bruun

    2014-01-01

    Polycystic ovary syndrome (PCOS) is associated with insulin resistance and increased risk of type 2 diabetes. Skeletal muscle is the major site of insulin mediated glucose disposal and the skeletal muscle tissue is capable to synthesize, convert and degrade androgens. Insulin sensitivity is conse......Polycystic ovary syndrome (PCOS) is associated with insulin resistance and increased risk of type 2 diabetes. Skeletal muscle is the major site of insulin mediated glucose disposal and the skeletal muscle tissue is capable to synthesize, convert and degrade androgens. Insulin sensitivity...... is conserved in cultured myotubes (in vitro) from patients with PCOS, but the effect of testosterone on this insulin sensitivity is unknown. We investigated the effect of 7days testosterone treatment (100nmol/l) on glucose transport and gene expression levels of hormone receptors and enzymes involved...... in the synthesis and conversion of testosterone (HSD17B1, HSD17B2, CYP19A1, SRD5A1-2, AR, ER-α, HSD17B6 and AKR1-3) in myotubes from ten patients with PCOS and ten matched controls. Testosterone treatment significantly increased aromatase and androgen receptor gene expression levels in patients and controls...

  6. Studies on insulin receptor, 1

    International Nuclear Information System (INIS)

    Sakai, Yukio

    1979-01-01

    The present study was designed for the purpose of establishing a method of insulin radioreceptor assay using plasma membranes of guinea pigs as receptor sites. The results obtained are as follows: 1) Insulin receptor in the renal plasma membranes of guinea pigs showed a significantly high affinity to porcine insulin compared with that in the plasma membranes of guinea pig liver or rat kidney and liver. 2) In the insulin radioreceptor assay, an optimum condition was observed by the incubation at 4 0 C for 24 - 48 hours with 100 μg membrane protein of guinea pig kidney and 0.08 ng of 125 I-insulin. This assay method was specific for insulin and showed an accurate biological activity of insulin. 3) The recovery rate of insulin radioreceptor assay was 98.4% and dilution check up to 16 times did not influence on the result. An average of coefficient variation was 3.92% within assay. All of these results indicated the method to be satisfactory. 4) Glucose induced insulin release by perfusion method in isolated Langerhans islets of rats showed an identical pattern of reaction curves between radioreceptor assay and radioimmunoassay, although the values of radioreceptor assay was slightly low. 5) Insulin free serum produced by ultra filtration method was added to the standard assay medium. By this procedure, direct measurement of human serum by radioreceptor assay became possible. 6) The value of human serum insulin receptor binding activity by the radioreceptor assay showed a high correlation with that of insulin radioimmunoassay in sera of normal, borderline or diabetic type defined by glucose tolerance test. (author)

  7. Studies of the Pro12Ala polymorphism of the peroxisome proliferator-activated receptor-gamma2 (PPAR-gamma2) gene in relation to insulin sensitivity among glucose tolerant caucasians

    DEFF Research Database (Denmark)

    Ek, J; Andersen, G; Urhammer, S A

    2001-01-01

    We examined whether the Pro12-Ala polymorphism of the human peroxisome proliferator-activated receptor-gamma2 (PPAR-gamma2) gene was related to altered insulin sensitivity among glucose-tolerant subjects or a lower accumulated incidence or prevalence of IGT and Type II (non-insulin-dependent) dia......-insulin-dependent) diabetes mellitus among Scandinavian Caucasians....

  8. Expression of an insulin/interleukin-1 receptor antagonist hybrid gene in insulin-producing cell lines (HIT-T15 and NIT-1) confers resistance against interleukin-1-induced nitric oxide production.

    Science.gov (United States)

    Welsh, N; Bendtzen, K; Welsh, M

    1995-01-01

    A hybrid gene consisting of the insulin gene enhancer/promoter region, the signal sequence, the insulin B- and C-chains, and the human interleukin-1 receptor antagonist (IL-1ra) gene was constructed. This hybrid gene was transfected together with the pSV2-neo construct into the insulin-producing cell lines HIT-T15 and NIT-1. One of the geneticin-selected clones, HITra2, expressed a 1.4-kb mRNA, which hybridized both to insulin and IL-1ra-cDNA in Northern blot analysis. Three proteins, with the mol wt 23, 17, and 14 kD, were immunoprecipitated with anti-IL-1ra antibodies from [35S]methionine-labeled HITra2 cells. Both at a low and at a high glucose concentration, 4-5 ng of IL-1ra/10(6) cells (ELISA) was released from these cells. On the other hand, a high glucose concentration evoked a three-fold increase in the release of insulin, suggesting that IL-1ra was released constitutively. Measured by nitrite production, transfected HIT, and NIT-1 cells exhibited a more than 10-fold decrease in IL-1 beta sensitivity. Since the conditioned culture media from the HITra2 cells exhibited an anti-IL-1 beta activity of only 0.5 U/ml, and mixed culture of HITra2 cells and isolated rat islets prevented IL-1 beta induced inhibition of insulin release, it is likely that IL-1ra acts locally at the cell surface. It is concluded that expression of a hybrid insulin/IL-1ra gene confers resistance to IL-1 and that this technique may be used to elucidate the role of IL-1 in autoimmune disorders such as insulin-dependent diabetes mellitus. Images PMID:7706480

  9. Characterization of the chicken muscle insulin receptor

    International Nuclear Information System (INIS)

    Adamo, M.; Simon, J.; Rosebrough, R.W.; McMurtry, J.P.; Steele, N.C.; LeRoith, D.

    1987-01-01

    Insulin receptors are present in chicken skeletal muscle. Crude membrane preparations demonstrated specific 125 I-insulin binding. The nonspecific binding was high (36-55% of total binding) and slightly lower affinity receptors were found than are typically observed for crude membrane insulin binding in other chicken tissues. Affinity crosslinking of 125 I-insulin to crude membranes revealed insulin receptor alpha-subunits of Mr 128K, intermediate between those of liver (134K) and brain (124K). When solubilized and partially purified on wheat germ agglutinin (WGA) affinity columns, chicken muscle insulin receptors exhibited typical high affinity binding, with approximately 10(-10) M unlabeled insulin producing 50% inhibition of the specific 125 I-insulin binding. WGA purified chicken muscle insulin receptors also exhibited insulin-stimulated autophosphorylation of the beta-subunit, which appeared as phosphorylated bands of 92- and 81K. Both bands were immunoprecipitated by anti-receptor antiserum (B10). WGA purified membranes also demonstrated dose-dependent insulin-stimulated phosphorylation of the exogenous substrate poly(Glu,Tyr)4:1. However, unlike chicken liver, chicken muscle insulin receptor number and tyrosine kinase activity were unaltered by 48 hr of fasting or 48 hr of fasting and 24 hr of refeeding. Thus, despite the presence of insulin receptors in chicken muscle showing normal coupling to receptor tyrosine kinase activity, nutritional alterations modulate these parameters in a tissue-specific manner in chickens

  10. NGA/Insulin receptor scanning

    International Nuclear Information System (INIS)

    Kurtaran, A.; Virgolini, I.

    1994-01-01

    Tc-99m-galactosyl-neoglycoalbumin (NGA) is one of the first receptor-based radiopharmaceuticals which specifically recognizes the hepatic binding protein (HBP) located on the surface of the hepatocytes. The exclusive interactin of NGA with HBP provided the basis for a kinetic model for the evaluation hepatocellular function. During the last years we have used NGA in more than 300 patients with various liver diseases including liver cirrhosis (Stages Child A to Child C), viral hepatitis, and carcinomas. In these studies, the calculated HBP densities, after i.v.-injection of Tc-99m-NGA, significantly correlated with the clinical course of the diseases. Furthermore, similar to conventional Tc-colloid, NGA provided excellent demonstration of 'cold spots' for hepatic masses. In a further approach we used another hepatocyte receptor-seeking radioligand, I-123-Tyr-A14- insulin, and found, that its in vitro-binding to hepatocellular carcinomas is greatly enhanced over normal hepatic tissue. On this basis, we developed a double-tracer method using NGA and insulin in a single study. Thus, areas of 'cold spots' identifying hepatic masses on NGA scans, take up I-123-Tyr-A14-insulin immediately after i.v.-injection. This was true for hepatocellular hepatomas, but not for adenocarcinomas. In conclusion, NGA/insulin receptor scanning could be a novel and save method for the demonstration of hepatocellular hepatomas. (author)

  11. NGA/Insulin receptor scanning

    Energy Technology Data Exchange (ETDEWEB)

    Kurtaran, A; Virgolini, I [Vienna Univ. (Austria). Abt. fuer Nuklearmedizin; Angelberger, P [Ludwig Boltzmann-Institut fuer Nuklearmedizin, Vienna (Austria)

    1994-10-01

    Tc-99m-galactosyl-neoglycoalbumin (NGA) is one of the first receptor-based radiopharmaceuticals which specifically recognizes the hepatic binding protein (HBP) located on the surface of the hepatocytes. The exclusive interactin of NGA with HBP provided the basis for a kinetic model for the evaluation hepatocellular function. During the last years we have used NGA in more than 300 patients with various liver diseases including liver cirrhosis (Stages Child A to Child C), viral hepatitis, and carcinomas. In these studies, the calculated HBP densities, after i.v.-injection of Tc-99m-NGA, significantly correlated with the clinical course of the diseases. Furthermore, similar to conventional Tc-colloid, NGA provided excellent demonstration of `cold spots` for hepatic masses. In a further approach we used another hepatocyte receptor-seeking radioligand, I-123-Tyr-A14- insulin, and found, that its in vitro-binding to hepatocellular carcinomas is greatly enhanced over normal hepatic tissue. On this basis, we developed a double-tracer method using NGA and insulin in a single study. Thus, areas of `cold spots` identifying hepatic masses on NGA scans, take up I-123-Tyr-A14-insulin immediately after i.v.-injection. This was true for hepatocellular hepatomas, but not for adenocarcinomas. In conclusion, NGA/insulin receptor scanning could be a novel and save method for the demonstration of hepatocellular hepatomas. (author).

  12. Polycystic ovary syndrome: association of a C/T single nucleotide polymorphism at tyrosine kinase domain of insulin receptor gene with pathogenesis among lean Japanese women.

    Science.gov (United States)

    Kashima, Katsunori; Yahata, Tetsuro; Fujita, Kazuyuki; Tanaka, Kenichi

    2013-01-01

    To assess whether the insulin receptor (INSR) gene contributes to genetic susceptibility to polycystic ovary syndrome (PCOS) in a Japanese population. We ex-amined the frequency of the His 1058 C/T single nucleotide polymorphism (SNP) found in exon 17 of the INSR gene in 61 Japanese PCOS patients and 99 Japanese healthy controls. In addition, we analyzed the association between the genotype of this SNP and the clinical phenotypes. The frequency of the C/C genotype was not significantly different between all PCOS patients (47.5%) and controls (35.4%). However, among the lean cases (body mass index PCOS patients (65.0%) as compared with controls (36.6%). We concluded that the His 1058 C/T polymorphism at the tyrosine kinase domain of the INSR gene had a relationship to the pathogenesis of lean PCOS patients in a Japanese population.

  13. Insulin receptors in the mammary gland

    International Nuclear Information System (INIS)

    Smith, D.H.

    1986-01-01

    Insulin binding studies were conducted using mammary membrane preparations to further the authors understanding of insulin's role in regulating mammary metabolism, particularly ruminant mammary metabolism. Specific objectives were to: (1) characterize insulin binding to bovine mammary microsomes and determine if the specificity and kinetics of binding indicate the presence of insulin receptors in bovine mammary gland; (2) examine and compare insulin binding by liver and mammary microsomes of the pig and dairy cow; (3) examine insulin binding to bovine milk fat globule membranes (MFGM) and evaluate this model's usefulness in assessing insulin receptor regulation in the mammary gland of the cow; (4) examine the effect of dietary fat in insulin binding by rat mammary and liver microsomes. The specificity and kinetics of 125 I-insulin binding of bovine mammary microsomes indicated the presence of insulin receptors in bovine mammary gland. Bovine liver and mammary microsomes specifically bound less 125 I-insulin than did the corresponding porcine microsomes, and mammary microsomes, regardless of species, specifically bound less 125 I-insulin than did liver microsomes. These differences in binding suggest differences in insulin responsiveness between pigs and cattle, as well as between the liver and mammary glands

  14. Polymorphism rs3123554 in the cannabinoid receptor gene type 2 (CNR2) reveals effects on body weight and insulin resistance in obese subjects.

    Science.gov (United States)

    de Luis, Daniel Antonio; Izaola, Olatz; Primo, David; de la Fuente, Beatriz; Aller, Rocio

    2017-10-01

    Few studies assessing the relationship between single nucleotide polymorphisms in CNR2 and obesity or its related metabolic parameters are available. To investigate the influence of polymorphism rs3123554 in the CNR2 receptor gene on obesity anthropometric parameters, insulin resistance, and adipokines in subjects with obesity. The study population consisted of 1027 obese subjects, who were performed bioelectrical impedance analyses, blood pressure measurements, serial assessments of dietary intake during three days, and biochemical tests. Genotypes GG, GA, and AA were found in 339 (33.0%), 467 (45.5%), and 221 (21.5%) respectively. Body mass index, weight, fat mass, waist circumference, insulin, HOMA-IR, and triglyceride and leptin levels were higher in A-allele carriers as compared to non A-allele carriers. No differences were seen in these parameters between the GA and AA genotypes. There were no statistical differences in dietary intake. The main study finding was the association of the minor allele of the SNP rs3123554 in the CNR2 gene with body weight and triglyceride, HOMA-IR, insulin, and leptin levels. Copyright © 2017 SEEN y SED. Publicado por Elsevier España, S.L.U. All rights reserved.

  15. Alternative splicing of exon 17 and a missense mutation in exon 20 of the insulin receptor gene in two brothers with a novel syndrome of insulin resistance (congenital fiber-type disproportion myopathy)

    DEFF Research Database (Denmark)

    Vorwerk, P; Christoffersen, C T; Müller, J

    1999-01-01

    to be compound heterozygotes for mutations in the IR gene. The maternal allele was alternatively spliced in exon 17 due to a point mutation in the -1 donor splice site of the exon. The abnormal skipping of exon 17 shifts the amino acid reading frame and leads to a truncated IR, missing the entire tyrosine kinase......The insulin receptor (IR) in two brothers with a rare syndrome of congenital muscle fiber type disproportion myopathy (CFTDM) associated with diabetes and severe insulin resistance was studied. By direct sequencing of Epstein-Barr virus-transformed lymphocytes both patients were found...... domain. In the correct spliced variant, the point mutation is silent and results in a normally translated IR. The paternal allele carries a missense mutation in the tyrosine kinase domain. All three cDNA variants were present in the lymphocytes of the patients. Purified IR from 293 cells overexpressing...

  16. Agonism and antagonism at the insulin receptor

    DEFF Research Database (Denmark)

    Knudsen, Louise; Hansen, Bo Falck; Jensen, Pia

    2012-01-01

    Insulin can trigger metabolic as well as mitogenic effects, the latter being pharmaceutically undesirable. An understanding of the structure/function relationships between insulin receptor (IR) binding and mitogenic/metabolic signalling would greatly facilitate the preclinical development of new...... insulin analogues. The occurrence of ligand agonism and antagonism is well described for G protein-coupled receptors (GPCRs) and other receptors but in general, with the exception of antibodies, not for receptor tyrosine kinases (RTKs). In the case of the IR, no natural ligand or insulin analogue has been...... shown to exhibit antagonistic properties, with the exception of a crosslinked insulin dimer (B29-B'29). However, synthetic monomeric or dimeric peptides targeting sites 1 or 2 of the IR were shown to be either agonists or antagonists. We found here that the S961 peptide, previously described to be an IR...

  17. Structural Perspectives of Insulin Receptor Isoform-Selective Insulin Analogs

    Czech Academy of Sciences Publication Activity Database

    Jiráček, Jiří; Žáková, Lenka

    2017-01-01

    Roč. 8, Jul 27 (2017), č. článku 167. ISSN 1664-2392 R&D Projects: GA ČR GA15-19018S Institutional support: RVO:61388963 Keywords : insulin receptor * insulin binding * analog * diabetes * glucose Subject RIV: CE - Biochemistry OBOR OECD: Biochemistry and molecular biology Impact factor: 3.675, year: 2016 http://journal.frontiersin.org/article/10.3389/fendo.2017.00167/full

  18. Insulin and insulin-like growth factor receptors and responses

    International Nuclear Information System (INIS)

    Roth, R.A.; Steele-Perkins, G.; Hari, J.; Stover, C.; Pierce, S.; Turner, J.; Edman, J.C.; Rutter, W.J.

    1988-01-01

    Insulin is a member of a family of structurally related hormones with diverse physiological functions. In humans, the best-characterized members of this family include insulin, insulin-like growth factor (IGF)-I, and IGF-II. Each of these three polypeptide hormones has its own distinct receptor. The structures of each of these receptors have now been deduced from analyses of isolated cDNA clones. To study further the responses mediated through these three different receptors, the authors have been studying cells expressing the proteins encoded by these three cDNAs. The isolated cDNAs have been transfected into Chinese hamster ovary (CHO) cells, and the resulting transfected cell lines have been characterized as to the ligand-binding activities and signal-transducing activities of the expressed proteins

  19. Founder effect in the Horn of Africa for an insulin receptor mutation that may impair receptor recycling

    DEFF Research Database (Denmark)

    Raffan, E; Soos, M A; Rocha, N

    2011-01-01

    Genetic insulin receptoropathies are a rare cause of severe insulin resistance. We identified the Ile119Met missense mutation in the insulin receptor INSR gene, previously reported in a Yemeni kindred, in four unrelated patients with Somali ancestry. We aimed to investigate a possible genetic...

  20. Insulin receptor internalization defect in an insulin-resistant mouse melanoma cell line

    International Nuclear Information System (INIS)

    Androlewicz, M.J.; Straus, D.S.; Brandenburg, D.F.

    1989-01-01

    Previous studies from this laboratory demonstrated that the PG19 mouse melanoma cell line does not exhibit a biological response to insulin, whereas melanoma x mouse embryo fibroblast hybrids do respond to insulin. To investigate the molecular basis of the insulin resistance of the PG19 melanoma cells, insulin receptors from the insulin-resistant melanoma cells and insulin-sensitive fibroblast x melanoma hybrid cells were analyzed by the technique of photoaffinity labeling using the photoprobe 125 I-NAPA-DP-insulin. Photolabeled insulin receptors from the two cell types have identical molecular weights as determined by SDS gel electrophoresis under reducing and nonreducing conditions, indicating that the receptors on the two cell lines are structurally similar. Insulin receptor internalization studies revealed that the hybrid cells internalize receptors to a high degree at 37 degree C, whereas the melanoma cells internalize receptors to a very low degree or not at all. The correlation between ability to internalize insulin receptors and sensitivity to insulin action in this system suggests that uptake of the insulin-receptor complex may be required for insulin action in these cells. Insulin receptors from the two cell lines autophosphorylate in a similar insulin-dependent manner both in vitro and in intact cells, indicating that insulin receptors on the melanoma and hybrid cells have functional tyrosine protein kinase activity. Therefore, the block in insulin action in the PG19 melanoma cells appears to reside at a step beyond insulin-stimulated receptor autophosphorylation

  1. Combining GLP-1 receptor agonists with insulin

    DEFF Research Database (Denmark)

    Holst, Jens Juul; Vilsbøll, T

    2013-01-01

    Due to the increasing prevalence of type 2 diabetes mellitus (T2DM), the emergent trend towards diagnosis in younger patients and the progressive nature of this disease, many more patients than before now require insulin to maintain glycaemic control. However, there is a degree of inertia among...... physicians and patients regarding the initiation and intensification of insulin therapy, in part due to concerns about the associated weight gain and increased risk of hypoglycaemia. Glucagon-like peptide-1 receptor agonists (GLP-1RAs) increase insulin release and suppress glucagon secretion in a glucose......, compared with insulin, the antihyperglycaemic efficacy of GLP-1RAs is limited. The combination of a GLP-1RA and insulin might thus be highly effective for optimal glucose control, ameliorating the adverse effects typically associated with insulin. Data from clinical studies support the therapeutic...

  2. Implications of compound heterozygous insulin receptor mutations in congenital muscle fibre type disproportion myopathy for the receptor kinase activation

    DEFF Research Database (Denmark)

    Klein, H H; Müller, R; Vestergaard, H

    1999-01-01

    We studied insulin receptor kinase activation in two brothers with congenital muscle fibre type disproportion myopathy and compound heterozygous mutations of the insulin receptor gene, their parents, and their unaffected brother. In the father who has a heterozygote Arg1174-->Gln mutation, in sit...

  3. Alternative splicing of exon 17 and a missense mutation in exon 20 of the insulin receptor gene in two brothers with a novel syndrome of insulin resistance (congenital fiber-type disproportion myopathy)

    DEFF Research Database (Denmark)

    Vorwerk, P; Christoffersen, C T; Müller, J

    1999-01-01

    The insulin receptor (IR) in two brothers with a rare syndrome of congenital muscle fiber type disproportion myopathy (CFTDM) associated with diabetes and severe insulin resistance was studied. By direct sequencing of Epstein-Barr virus-transformed lymphocytes both patients were found...... either of the two mutated receptors lacked basal or stimulated IR beta-subunit autophosphorylation. A third brother who inherited both normal alleles has an normal muscle phenotype and insulin sensitivity, suggesting a direct linkage of these IR mutations with the CFTDM phenotype....

  4. Absence of down-regulation of the insulin receptor by insulin. A possible mechanism of insulin resistance in the rat.

    OpenAIRE

    Walker, A P; Flint, D J

    1983-01-01

    Insulin resistance occurs in rat adipocytes during pregnancy and lactation despite increased or normal insulin binding respectively; this suggests that a post-receptor defect exists. The possibility has been examined that, although insulin binding occurs normally, internalization of insulin or its receptor may be impaired in these states. Insulin produced a dose-dependent reduction in the number of insulin receptors on adipocytes from virgin rats maintained in culture medium, probably due to ...

  5. Obesity genes and insulin resistance.

    Science.gov (United States)

    Belkina, Anna C; Denis, Gerald V

    2010-10-01

    The exploding prevalence of insulin resistance and Type 2 diabetes (T2D) linked to obesity has become an alarming public health concern. Worldwide, approximately 171 million people suffer from obesity-induced diabetes and public health authorities expect this situation to deteriorate rapidly. An interesting clinical population of 'metabolically healthy but obese' (MHO) cases is relatively protected from T2D and its associated cardiovascular risk. The molecular basis for this protection is not well understood but is likely to involve reduced inflammatory responses. The inflammatory cells and pathways that respond to overnutrition are the primary subject matter for this review. The chance discovery of a genetic mutation in the Brd2 gene, which is located in the class II major histocompatibility complex and makes mice enormously fat but protects them from diabetes, offers revolutionary new insights into the cellular mechanisms that link obesity to insulin resistance and T2D. These Brd2-hypomorphic mice have reduced inflammation in fat that is normally associated with insulin resistance, and resemble MHO patients, suggesting novel therapeutic pathways for obese patients at risk for T2D. Deeper understanding of the functional links between genes that control inflammatory responses to diet-induced obesity is crucial to the development of therapies for obese, insulin-resistant patients.

  6. Autophagy downregulation contributes to insulin resistance mediated injury in insulin receptor knockout podocytes in vitro

    Directory of Open Access Journals (Sweden)

    Ying Xu

    2016-04-01

    Full Text Available It is unknown whether autophagy activity is altered in insulin resistant podocytes and whether autophagy could be a therapeutic target for diabetic nephropathy (DN. Here we used shRNA transfection to knockdown the insulin receptor (IR gene in cultured human immortalized podocytes as an in vitro insulin resistant model. Autophagy related proteins LC3, Beclin, and p62 as well as nephrin, a podocyte injury marker, were assessed using western blot and immunofluorescence staining. Our results show that autophagy is suppressed when podocytes lose insulin sensitivity and that treatment of rapamycin, an mTOR specific inhibitor, could attenuate insulin resistance induced podocytes injury via autophagy activation. The present study deepens our understanding of the role of autophagy in the pathogenesis of DN.

  7. [Mutation in the beta3-adrenergic receptor gene (Trp64Arg) does not influence insulin resistence, energy metabolism, fat distribution and lipid spectrum in young people. Pilot study].

    Science.gov (United States)

    Bendlová, B; Mazura, I; Vcelák, J; Pelikánová, T; Kunesová, M; Hainer, V; Obenberger, J; Palyzová, D

    1999-05-01

    A missence mutation Trp64Arg in the beta3-adrenergic receptor gene is associated with obesity, insulin resistance, a lower metabolic rate and the earlier onset of NIDDM but the published results are controversial. We investigated the effect of this mutation on insulin resistance (euglycemic hyperinsulinemic clamp), on fat mass and fat distribution (anthropometry, bioimpedance, CT) and resting metabolic rate (indirect calorimetry), lipid spectrum and other metabolic disturbances in Czech juveniles recruited from juvenile hypertensives (H, n = 68) and controls (C, n = 81). The frequency of this mutation (determined by digestion of 210 bp PCR product with MvaI) was double in H than in C (14.7%, vs. 7.4%) and the carriers of Arg64 allele had sig. higher fasting glucose (H: p = 0.002. C: p = 0.025). Four Trp64/Arg64 and six Trp64/Trp64 men (age 23 +/- 4.2, vs. 22.5 +/- 1.9 y, BMI 26 +/- 5.5, vs. 22.9 +/- 5.1 kg/m2) took part in a detailed pilot study. But no signif. differences (Horn's method) in fasting glucose (4.6 +/- 0.6, vs. 4.9 +/- 0.4 mmol/l), in parameters of insulin resistance (M-value150-180 min. 9.1 +/- 1.1, vs. 8.9 +/- 1.5 mg glucose/kg.min(-1)), resting metabolic rate/lean body mass (RMR/kg LBM: 78.6 +/- 4.6, vs. 85.6 +/- 23.2 kJ/kg), lipid spectrum and other screened parameters were found. The lowest resting metabolic rate (RMR/kg LBM 55.4; 62.6 kJ/kg) was found in brothers (both C, Trp64/Trp64) who highly differ in body constitution (BMI 19.0 resp. 32.4 kg/m2). We suppose that in this case the energy metabolism is probably determined by other genetic loci and does not correlate with body fat mass. Our pilot study does not confirm the influence of Trp64Arg mutation in heterozygous carriers on insulin resistance, energy metabolism and lipid spectrum.

  8. Changing the insulin receptor to possess insulin-like growth factor I ligand specificity

    International Nuclear Information System (INIS)

    Andersen, A.S.; Kjeldsen, T.; Wiberg, F.C.; Christensen, P.M.; Rasmussen, J.S.; Norris, K.; Moeller, K.B.; Moeller, N.P.H.

    1990-01-01

    To examine the role of the N-terminal part of the insulin-like growth factor I (IGF-I) receptor and insulin receptor in determining ligand specificity, the authors prepared an expression vector encoding a hybrid receptor where exon 1 (encoding the signal peptide and seven amino acids of the α-subunit), exon 2, and exon 3 of the insulin receptor were replaced with the corresponding IGF-I receptor cDNA (938 nucleotides). To allow direct quantitative comparison of the binding capabilities of this hybrid receptor with those of the human IGF-I receptor and the insulin receptor, all three receptors were expressed in baby hamster kidney (BHK) cells as soluble molecules and partially purified before characterization. The hybrid IGF-I/insulin receptor bound IGF-I with an affinity comparable to that of the wild-type IGF-I receptor. In contrast, the hybrid receptor no longer displayed high-affinity binding of insulin. These results directly demonstrate that it is possible to change the specificity of the insulin receptor to that of the IGF-I receptor and, furthermore, that the binding specificity for IGF-I is encoded within the nucleotide sequence from 135 to 938 of the IGF-I receptor cDNA. Since the hybrid receptor only bound insulin with low affinity, the insulin binding region is likely to be located within exons 2 and 3 of the insulin receptor

  9. 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.

  10. Leptin stimulates hepatic growth hormone receptor and insulin-like growth factor gene expression in a teleost fish, the hybrid striped bass.

    Science.gov (United States)

    Won, Eugene T; Douros, Jonathan D; Hurt, David A; Borski, Russell J

    2016-04-01

    Leptin is an anorexigenic peptide hormone that circulates as an indicator of adiposity in mammals, and functions to maintain energy homeostasis by balancing feeding and energy expenditure. In fish, leptin tends to be predominantly expressed in the liver, another important energy storing tissue, rather than in fat depots as it is in mammals. The liver also produces the majority of circulating insulin-like growth factors (IGFs), which comprise the mitogenic component of the growth hormone (GH)-IGF endocrine growth axis. Based on similar regulatory patterns of leptin and IGFs that we have documented in previous studies on hybrid striped bass (HSB: Morone saxatilis×Morone chrysops), and considering the co-localization of these peptides in the liver, we hypothesized that leptin might regulate the endocrine growth axis in a manner that helps coordinate somatic growth with energy availability. Using a HSB hepatocyte culture system to simulate autocrine or paracrine exposure that might occur within the liver, this study examines the potential for leptin to modulate metabolism and growth through regulation of IGF gene expression directly, or indirectly through the regulation of GH receptors (GHR), which mediate GH-induced IGF expression. First, we verified that GH (50nM) has a classical stimulatory effect on IGF-1 and additionally show it stimulates IGF-2 transcription in hepatocytes. Leptin (5 and/or 50nM) directly stimulated in vitro GHR2 gene expression within 8h of exposure, and both GHR1 and GHR2 as well as IGF-1 and IGF-2 gene expression after 24h. Cells were then co-incubated with submaximal concentrations of leptin and GH (25nM each) to test if they had a synergistic effect on IGF gene expression, possibly through increased GH sensitivity following GHR upregulation by leptin. In combination, however, the treatments only had an additive effect on stimulating IGF-1 mRNA despite their capacity to increase GHR mRNA abundance. This suggests that leptin's stimulatory

  11. Quercetin suppresses insulin receptor signaling through inhibition of the insulin ligand–receptor binding and therefore impairs cancer cell proliferation

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Feng [Department of Gastroenterology, The Tenth People’s Hospital of Shanghai, Tongji University, Shanghai 200072 (China); Department of Nanomedicine, Houston Methodist Research Institute, Houston, TX 77030 (United States); Yang, Yong, E-mail: yyang@houstonmethodist.org [Department of Nanomedicine, Houston Methodist Research Institute, Houston, TX 77030 (United States); Department of Medicine, Weill Cornell Medical College, New York, NY 10065 (United States)

    2014-10-03

    Graphical abstract: - Highlights: • Quercetin inhibits insulin ligand–receptor interactions. • Quercetin reduces downstream insulin receptor signaling. • Quercetin blocks insulin induced glucose uptake. • Quercetin suppresses insulin stimulated cancer cell proliferation and tumor growth. - Abstract: Although the flavonoid quercetin is known to inhibit activation of insulin receptor signaling, the inhibitory mechanism is largely unknown. In this study, we demonstrate that quercetin suppresses insulin induced dimerization of the insulin receptor (IR) through interfering with ligand–receptor interactions, which reduces the phosphorylation of IR and Akt. This inhibitory effect further inhibits insulin stimulated glucose uptake due to decreased cell membrane translocation of glucose transporter 4 (GLUT4), resulting in impaired cancer cell proliferation. The effect of quercetin in inhibiting tumor growth was also evident in an in vivo model, indicating a potential future application for quercetin in the treatment of cancers.

  12. Quercetin suppresses insulin receptor signaling through inhibition of the insulin ligand–receptor binding and therefore impairs cancer cell proliferation

    International Nuclear Information System (INIS)

    Wang, Feng; Yang, Yong

    2014-01-01

    Graphical abstract: - Highlights: • Quercetin inhibits insulin ligand–receptor interactions. • Quercetin reduces downstream insulin receptor signaling. • Quercetin blocks insulin induced glucose uptake. • Quercetin suppresses insulin stimulated cancer cell proliferation and tumor growth. - Abstract: Although the flavonoid quercetin is known to inhibit activation of insulin receptor signaling, the inhibitory mechanism is largely unknown. In this study, we demonstrate that quercetin suppresses insulin induced dimerization of the insulin receptor (IR) through interfering with ligand–receptor interactions, which reduces the phosphorylation of IR and Akt. This inhibitory effect further inhibits insulin stimulated glucose uptake due to decreased cell membrane translocation of glucose transporter 4 (GLUT4), resulting in impaired cancer cell proliferation. The effect of quercetin in inhibiting tumor growth was also evident in an in vivo model, indicating a potential future application for quercetin in the treatment of cancers

  13. Aminoacid polymorphisms of insulin receptor substrate-1 in non-insulin-dependent diabetes mellitus

    DEFF Research Database (Denmark)

    Almind, K; Bjørbaek, C; Vestergaard, H

    1993-01-01

    Since relative or absolute insulin deficiency and insulin insensitivity are involved in the aetiology of non-insulin-dependent diabetes mellitus (NIDDM), we examined whether patients with NIDDM exhibit genetic variability in the coding region of insulin receptor substrate-1 (IRS-1), a candidate...

  14. Nature and regulation of the insulin receptor: structure and function

    International Nuclear Information System (INIS)

    Czech, M.P.

    1985-01-01

    Native, cell-surface insulin receptor consists of two glycoprotein subunit types with apparent masses of about 125,000 daltons (alpha subunit) and 90,000 daltons (beta subunit). The alpha and beta insulin-receptor subunits seem to have distinct functions such that alpha appears to bind hormone whereas beta appears to possess intrinsic tyrosine kinase activity. In detergent extracts, insulin activates receptor autophosphorylation of tyrosine residues on its beta subunit, whereas in the presence of reductant, the alpha subunit is also phosphorylated. In intact cells, insulin activates serine/threonine phosphorylation of insulin receptor beta subunit as well as tyrosine phosphorylation. The biological role of the receptor-associated tyrosine kinase is not known. The insulin receptor kinase is regulated by beta-adrenergic agonists and other agents that elevate cAMP in adipocytes, presumably via the cAMP-dependent protein kinase. Such agents decrease receptor affinity for insulin and partially uncouple receptor tyrosine kinase activity from activation by insulin. These effects appear to contribute to the biological antagonism between insulin and beta-agonists. These data suggest the hypothesis that a complex network of tyrosine and serine/threonine phosphorylations on the insulin receptor modulate its binding and kinase activities in an antagonistic manner

  15. 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

  16. 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.

  17. Relationships of plasma adiponectin level and adiponectin receptors 1 and 2 gene expression to insulin sensitivity and glucose and fat metabolism in monozygotic and dizygotic twins

    DEFF Research Database (Denmark)

    Storgaard, Heidi; Poulsen, Pernille; Ling, Charlotte

    2007-01-01

    and muscle AdipoR1/R2 gene expression and the impact of these components on in vivo glucose and fat metabolism. DESIGN AND PARTICIPANTS: Plasma adiponectin and muscle gene expression of AdipoR1/R2 were measured before and during insulin infusion in 89 young and 69 elderly monozygotic and dizygotic twins...... influenced by age, sex, abdominal obesity, and aerobic capacity. Intrapair correlations in monozygotic twins indicated a nongenetic influence of birth weight on plasma adiponectin and AdipoR2 expression. Nonoxidative glucose metabolism was associated with AdipoR1 and plasma adiponectin, in young and elderly...

  18. Studies of relationships between variation of the human G protein-coupled receptor 40 Gene and Type 2 diabetes and insulin release

    DEFF Research Database (Denmark)

    Hamid, Y H; Vissing, H; Holst, B

    2005-01-01

    AIMS: Recently, a novel human G protein-coupled receptor 40 (GPR40), which is predominantly expressed in pancreatic islets, was shown to mediate an amplifying effect of long-chain fatty acids on glucose-induced insulin secretion. The present aim was to examine the coding region of GPR40 for varia......AIMS: Recently, a novel human G protein-coupled receptor 40 (GPR40), which is predominantly expressed in pancreatic islets, was shown to mediate an amplifying effect of long-chain fatty acids on glucose-induced insulin secretion. The present aim was to examine the coding region of GPR40...... compared with the wild type (P = 0.01). The Arg211His polymorphism had a similar allele frequency among 1384 Type 2 diabetic patients [MAF%; 23.4 (95% CI: 21.8-25.0)] and 4424 middle-aged glucose-tolerant subjects [24.1% (23.2-25.0)]. A genotype-quantitative trait study of 5597 non-diabetic, middle...

  19. Development of real-time reverse transcription polymerase chain reaction assays to quantify insulin-like growth factor receptor and insulin receptor expression in equine tissue

    Directory of Open Access Journals (Sweden)

    Stephen B. Hughes

    2013-08-01

    Full Text Available The insulin-like growth factor system (insulin-like growth factor 1, insulin-like growth factor 2, insulin-like growth factor 1 receptor, insulin-like growth factor 2 receptor and six insulin-like growth factor-binding proteins and insulin are essential to muscle metabolism and most aspects of male and female reproduction. Insulin-like growth factor and insulin play important roles in the regulation of cell growth, differentiation and the maintenance of cell differentiation in mammals. In order to better understand the local factors that regulate equine physiology, such as muscle metabolism and reproduction (e.g., germ cell development and fertilisation, real-time reverse transcription polymerase chain reaction assays for quantification of equine insulin-like growth factor 1 receptor and insulin receptor messenger ribonucleic acid were developed. The assays were sensitive: 192 copies/µLand 891 copies/µL for insulin-like growth factor 1 receptor, messenger ribonucleic acid and insulin receptor respectively (95%limit of detection, and efficient: 1.01 for the insulin-like growth factor 1 receptor assay and 0.95 for the insulin receptor assay. The assays had a broad linear range of detection (seven logs for insulin-like growth factor 1 receptor and six logs for insulin receptor. This allowed for analysis of very small amounts of messenger ribonucleic acid. Low concentrations of both insulin-like growth factor 1 receptor and insulin receptor messenger ribonucleic acid were detected in endometrium, lung and spleen samples, whilst high concentrations were detected in heart, muscle and kidney samples, this was most likely due to the high level of glucose metabolism and glucose utilisation by these tissues. The assays developed for insulin-like growth factor 1 receptor and insulin receptor messenger ribonucleic acid expression have been shown to work on equine tissue and will contribute to the understanding of insulin and insulin-like growth factor 1

  20. Severe hypoglycaemia in a person with insulin autoimmune syndrome accompanied by insulin receptor anomaly type B.

    Science.gov (United States)

    Kato, T; Itoh, M; Hanashita, J; Itoi, T; Matsumoto, T; Ono, Y; Imamura, S; Hayakawa, N; Suzuki, A; Mizutani, Y; Uchigata, Y; Oda, N

    2007-11-01

    A rare case of the insulin autoimmune syndrome (IAS) accompanied by insulin receptor anomaly is reported. Antibodies to insulin and insulin receptor were determined in the patient with severe hypoglycaemia before and after the treatment with prednisolone. Titers of antibody to insulin and insulin receptors were 73.0% and 41.5%, respectively. Drug-induced lymphocyte stimulation tests were all negative for the suspicious drugs. Her HLA-DR was DRB1*0403/04051. Following steroid therapy, the formation of antibodies was suppressed and alleviated her symptoms. Scatchard analysis yielded findings specific to polyclonal antibodies. The changes in autoantibodies resulted in alleviation of the hypoglycemic symptoms as a result of steroid therapy.

  1. Insulin receptor degradation is accelerated in cultured lymphocytes from patients with genetic syndromes of extreme insulin resistance

    International Nuclear Information System (INIS)

    McElduff, A.; Hedo, J.A.; Taylor, S.I.; Roth, J.; Gorden, P.

    1984-01-01

    The insulin receptor degradation rate was examined in B lymphocytes that were obtained from peripheral blood of normal subjects and patients with several syndromes of extreme insulin resistance. The insulin receptors were surface labeled using Na 125 I/lactoperoxidase and the cells were returned to incubate in growth media. After varying periods of incubation, aliquots of cells were solubilized and the cell content of labeled receptor subunits were measured by immunoprecipitation with anti-receptor antibodies and NaDodSO4/polyacrylamide gel electrophoresis. In cell lines from four patients in whom the number of insulin receptors was reduced by greater than 90%, the rate of receptor loss was greater than normal (t1/2 equals 3.8 +/- 0.9 h vs. 6.5 +/- 1.2 h; mean +/- SD, P less than 0.01). However, a similar acceleration in receptor degradation was seen in cells from five patients with extreme insulin resistance but low-normal insulin receptor concentration (t1/2 equals 4.4 +/- 0.9 h). Thus, all the patients with genetic syndromes of insulin resistance had accelerated receptor degradation, regardless of their receptor concentration. By contrast, insulin receptors on cultured lymphocytes that were obtained from patients with extreme insulin resistance secondary to autoantibodies to the insulin receptor had normal receptor degradation (t1/2 equals 6.1 +/- 1.9 h). We conclude that (a) accelerated insulin receptor degradation is an additional feature of cells from patients with genetic forms of insulin resistance; (b) that accelerated insulin receptor degradation may explain the low-normal receptor concentrations that were seen in some patients with extreme insulin resistance; and (c) that accelerated degradation does not explain the decreased receptor concentration in patients with very low insulin receptor binding and, therefore, by inference, a defect in receptor synthesis must be present in this subgroup

  2. Investigations on the insulin receptor of isolated fat cells

    International Nuclear Information System (INIS)

    Eichler, W.

    1980-01-01

    Fat cells, isolated from the epididymal adipose tissue of rats, were incubed with iodine 125 insulin after previous incubation with various antagonists. By varying the antagonist concentration, it was possible to determine the effect these substances have on the insulin receptor, i.e. the insulin similarity. By varying the preincubation time, toxicity of the test substances could be detected, which pretended repression effects; and by finally verying the incubation time the effects on the receptor via the membrane could be distinguished from direct receptor bindings of the antagonist. (orig./MG) [de

  3. Insulin resistance in uremia: Insulin receptor kinase activity in liver and muscle from chronic uremic rats

    International Nuclear Information System (INIS)

    Cecchin, F.; Ittoop, O.; Sinha, M.K.; Caro, J.F.

    1988-01-01

    The authors have studied the structure and function of the partially purified insulin receptors from liver and skeletal muscle in a rat model of severe chronic uremia. 125 I-insulin binding was higher in the liver from uremic rats when compared with ad libitum- and pair-fed controls. Furthermore, the ability of insulin to stimulate the autophosphorylation of the β-subunit and insulin receptor kinase activity using Glu 80 , Tyr 20 as exogenous phosphoacceptor was increased in the liver of the uremic animals. The structural characteristics of the receptors, as determined by electrophoretic mobilities of affinity labeled α-subunit and the phosphorylated β-subunit, were normal in uremia. 125 I-insulin binding and insulin receptor kinase activity were similar in the skeletal muscle from uremic and pair- and ad libitum-fed animals. Thus the data are supportive of the hypothesis that in liver and muscle of chronic uremic rats, insulin resistance is due to a defect(s) distal to the insulin receptor kinase

  4. Studies on insulin receptor, 2. Studies on the influence of starvation and high fat diet on insulin receptor

    Energy Technology Data Exchange (ETDEWEB)

    Sakai, Y [Hiroshima Univ. (Japan). School of Medicine

    1979-08-01

    The present study is to investigate an influence of starvation and high fat diet on insulin receptor of the plasma membrane by means of radioreceptor assay using /sup 125/I-labelled insulin. Male guinea pigs of Hartley strain were employed for the starvation study, and /sup 125/I-insulin binding capacity on the plasma membrane of the liver and kidney was determined at 24, 48 and 72 hours of the fast after the last meal. Male rats of Wistar strain were employed for the high fat study where the diet containing 35% of butter was fed ad libitum for 38 or 68 days. The animals were killed at the fast of 12 hours, and /sup 125/I-insulin binding capacity on the plasma membrane of the liver was determined. The results obtained are summarized as follows: 1) An increase in /sup 125/I-insulin binding capacity on the plasma membrane of the liver and kidney was observed by the starvation for 24 to 72 hours. 2) The mechanism of the increase by starvation was considered to be different by the organs; it was due to an increase in number of insulin receptor in the liver, and due to an increase in affinity of insulin receptor in the kidney. 3) In non-obese rats fed with high fat diet, the number of insulin receptor on the liver plasma membrane showed a decrease, and this observation clearly indicated that the decrease in number of the receptor did not depend on the obesity. 4) Obese rats also fed with high fat diet presented a decrease in number of insulin receptor without an elevation of insulin levels in the circulating blood. This indicated that at least in the obese rats fed with high fat diet, the decrease in number of the receptor was not due to hyperinsulinemia.

  5. Acute stimulation of brain mu opioid receptors inhibits glucose-stimulated insulin secretion via sympathetic innervation.

    Science.gov (United States)

    Tudurí, Eva; Beiroa, Daniel; Stegbauer, Johannes; Fernø, Johan; López, Miguel; Diéguez, Carlos; Nogueiras, Rubén

    2016-11-01

    Pancreatic insulin-secreting β-cells express opioid receptors, whose activation by opioid peptides modulates hormone secretion. Opioid receptors are also expressed in multiple brain regions including the hypothalamus, where they play a role in feeding behavior and energy homeostasis, but their potential role in central regulation of glucose metabolism is unknown. Here, we investigate whether central opioid receptors participate in the regulation of insulin secretion and glucose homeostasis in vivo. C57BL/6J mice were acutely treated by intracerebroventricular (i.c.v.) injection with specific agonists for the three main opioid receptors, kappa (KOR), delta (DOR) and mu (MOR) opioid receptors: activation of KOR and DOR did not alter glucose tolerance, whereas activation of brain MOR with the specific agonist DAMGO blunted glucose-stimulated insulin secretion (GSIS), reduced insulin sensitivity, increased the expression of gluconeogenic genes in the liver and, consequently, impaired glucose tolerance. Pharmacological blockade of α2A-adrenergic receptors prevented DAMGO-induced glucose intolerance and gluconeogenesis. Accordingly, DAMGO failed to inhibit GSIS and to impair glucose tolerance in α2A-adrenoceptor knockout mice, indicating that the effects of central MOR activation on β-cells are mediated via sympathetic innervation. Our results show for the first time a new role of the central opioid system, specifically the MOR, in the regulation of insulin secretion and glucose metabolism. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Impact of the growth hormone receptor exon 3 deletion gene polymorphism on glucose metabolism, lipids, and insulin-like growth factor-I levels during puberty

    DEFF Research Database (Denmark)

    Sørensen, Kaspar; Aksglaede, Lise; Munch-Andersen, Thor

    2009-01-01

    . PARTICIPANTS: Participants included 142 healthy Caucasian subjects (65 boys) aged 8.5-16.1 yr. Interventions: Standard 2-h oral glucose tolerance tests were preformed. GHR genotypes were determined by multiplex PCR. Main outcome measures were insulin sensitivity, insulin secretion, serum lipids, and IGF......-I levels. RESULTS: Insulin secretion was higher in children and adolescents with a least one GHRd3 allele, even after adjustment for age, sex, pubertal stage, and insulin sensitivity (P = 0.018). Disposition index was higher in GHRd3-positive subjects (P = 0.026). In addition, the GHRd3 allele...... was associated with higher triglyceride (P = 0.028), but not IGF-I levels. CONCLUSION: The presence of at least one GHRd3 allele was associated with higher insulin secretion for a given degree of insulin sensitivity in healthy children and adolescents during puberty. In addition, the presence of the GHRd3 allele...

  7. Expression of insulin receptor spliced variants and their functional correlates in muscle from patients with non-insulin-dependent diabetes mellitus

    DEFF Research Database (Denmark)

    Hansen, Torben; Bjørbaek, C; Vestergaard, H

    1993-01-01

    Due to alternative splicing of exon 11 of the receptor gene, the human insulin receptor exists in two forms, that have distinct tissue-specific expression and are functionally different. Needle biopsies obtained from vastus lateralis muscle from 20 patients with noninsulin-dependent diabetes...... kinase activity were examined in wheat germ agglutinin-purified insulin receptors isolated from muscle biopsies. Moreover, insulin-stimulated glucose disposal was studied by means of the euglycemic hyperinsulinemic clamp technique. No difference in the relative expression of spliced variants......, and tyrosine kinase activity toward the exogenous substrate poly(Glu-Tyr(4:1)). Furthermore, no significant relationship was demonstrated between the glucose disposal rate and the relative expression of insulin receptor splice variants. In conclusion, in skeletal muscle from both normal control subjects...

  8. The antimicrobial peptide derived from insulin-like growth factor-binding protein 5, AMP-IBP5, regulates keratinocyte functions through Mas-related gene X receptors.

    Science.gov (United States)

    Chieosilapatham, Panjit; Niyonsaba, François; Kiatsurayanon, Chanisa; Okumura, Ko; Ikeda, Shigaku; Ogawa, Hideoki

    2017-10-01

    In addition to their microbicidal properties, host defense peptides (HDPs) display various immunomodulatory functions, including keratinocyte production of cytokines/chemokines, proliferation, migration and wound healing. Recently, a novel HDP named AMP-IBP5 (antimicrobial peptide derived from insulin-like growth factor-binding protein 5) was shown to exhibit antimicrobial activity against numerous pathogens, even at concentrations comparable to those of human β-defensins and LL-37. However, the immunomodulatory role of AMP-IBP5 in cutaneous tissue remains unknown. To investigate whether AMP-IBP5 triggers keratinocyte activation and to clarify its mechanism. Production of cytokines/chemokines and growth factors was determined by appropriate ELISA kits. Cell migration was assessed by in vitro wound closure assay, whereas cell proliferation was analyzed using BrdU incorporation assay complimented with XTT assay. MAPK and NF-κB activation was determined by Western blotting. Intracellular cAMP levels were assessed using cAMP enzyme immunoassay kit. Among various cytokines/chemokines and growth factors tested, AMP-IBP5 selectively increased the production of IL-8 and VEGF. Moreover, AMP-IBP5 markedly enhanced keratinocyte migration and proliferation. AMP-IBP5-induced keratinocyte activation was mediated by Mrg X1-X4 receptors with MAPK and NF-κB pathways working downstream, as evidenced by the inhibitory effects of MrgX1-X4 siRNAs and ERK-, JNK-, p38- and NF-κB-specific inhibitors. We confirmed that AMP-IBP5 indeed induced MAPK and NF-κB activation. Furthermore, AMP-IBP5-induced VEGF but not IL-8 production correlated with an increase in intracellular cAMP. Our findings suggest that in addition to its antimicrobial function, AMP-IBP5 might contribute to wound healing process through activation of keratinocytes. Copyright © 2017 Japanese Society for Investigative Dermatology. Published by Elsevier B.V. All rights reserved.

  9. Insulin decreases atherosclerosis by inducing endothelin receptor B expression

    DEFF Research Database (Denmark)

    Park, Kyoungmin; Mima, Akira; Li, Qian

    2016-01-01

    Endothelial cell (EC) insulin resistance and dysfunction, caused by diabetes, accelerates atherosclerosis. It is unknown whether specifically enhancing EC-targeted insulin action can decrease atherosclerosis in diabetes. Accordingly, overexpressing insulin receptor substrate-1 (IRS1...... induction of NO action, which increases endothelin receptor B (EDNRB) expression and intracellular [Ca(2+)]. Using the mice with knockin mutation of eNOS, which had Ser1176 mutated to alanine (AKI), deleting the only known mechanism for insulin to activate eNOS/NO pathway, we observed that IRS1...... overexpression in the endothelia of Aki/ApoE(-/-) mice significantly decreased atherosclerosis. Interestingly, endothelial EDNRB expression was selectively reduced in intima of arteries from diabetic patients and rodents. However, endothelial EDNRB expression was upregulated by insulin via P13K/Akt pathway...

  10. The role of insulin receptor signaling in the brain.

    Science.gov (United States)

    Plum, Leona; Schubert, Markus; Brüning, Jens C

    2005-03-01

    The insulin receptor (IR) is expressed in various regions of the developing and adult brain, and its functions have become the focus of recent research. Insulin enters the central nervous system (CNS) through the blood-brain barrier by receptor-mediated transport to regulate food intake, sympathetic activity and peripheral insulin action through the inhibition of hepatic gluconeogenesis and reproductive endocrinology. On a molecular level, some of the effects of insulin converge with those of the leptin signaling machinery at the point of activation of phosphatidylinositol 3-kinase (PI3K), resulting in the regulation of ATP-dependent potassium channels. Furthermore, insulin inhibits neuronal apoptosis via activation of protein kinase B in vitro, and it regulates phosphorylation of tau, metabolism of the amyloid precursor protein and clearance of beta-amyloid from the brain in vivo. These findings indicate that neuronal IR signaling has a direct role in the link between energy homeostasis, reproduction and the development of neurodegenerative diseases.

  11. Characterisation of adiponectin multimers and the IGF axis in humans with a heterozygote mutation in the tyrosine kinase domain of the insulin receptor gene

    DEFF Research Database (Denmark)

    Højlund, Kurt; Beck-Nielsen, Henning; Flyvbjerg, Allan

    2012-01-01

    Objective: Low levels of adiponectin, IGF-binding protein (IGFBP)-1, and IGFBP-2, and high levels of leptin correlate with several indices of insulin resistance and risk of type 2 diabetes. However, in insulin receptoropathies plasma adiponectin is paradoxically increased despite severe insulin...... resistance, whereas the IGF-axis is sparsely described. Here, we aimed to characterize the multimeric distribution of adiponectin and the IGF-axis in humans with a heterozygous INSR mutation (Arg1174Gln).Methods: Blood samples obtained in six Arg1174Gln-carriers and 10 lean, healthy controls before and after...... an euglycemic-hyperinsulinemic clamp were examined for plasma adiponectin multimers, leptin, total IGF-I, IGF-II, free IGF-I, IGFBP-1 and IGFBP-2.Results: Despite 10-fold elevated fasting insulin and marked insulin resistance in Arg1174Gln-carriers, the levels of total adiponectin, leptin, IGFBP-1 and IGFBP-2...

  12. Aminoacid polymorphisms of insulin receptor substrate-1 in non-insulin-dependent diabetes mellitus

    DEFF Research Database (Denmark)

    Almind, K; Bjørbaek, C; Vestergaard, H

    1993-01-01

    Since relative or absolute insulin deficiency and insulin insensitivity are involved in the aetiology of non-insulin-dependent diabetes mellitus (NIDDM), we examined whether patients with NIDDM exhibit genetic variability in the coding region of insulin receptor substrate-1 (IRS-1), a candidate...... with NIDDM and 3 of the controls were heterozygous at codon 972 for a polymorphism in which glycine was substituted with arginine. Moreover, at codon 513, 6 patients with NIDDM and 2 controls had a heterozygous polymorphism with a transition from alanine to proline. None of the polymorphism carriers had both...

  13. Melatonin Receptor Genes in Vertebrates

    Directory of Open Access Journals (Sweden)

    Hua Dong Yin

    2013-05-01

    Full Text Available Melatonin receptors are members of the G protein-coupled receptor (GPCR family. Three genes for melatonin receptors have been cloned. The MT1 (or Mel1a or MTNR1A and MT2 (or Mel1b or MTNR1B receptor subtypes are present in humans and other mammals, while an additional melatonin receptor subtype, Mel1c (or MTNR1C, has been identified in fish, amphibians and birds. Another melatonin related orphan receptor, GPR50, which does not bind melatonin, is found exclusively in mammals. The hormone melatonin is secreted primarily by the pineal gland, with highest levels occurring during the dark period of a circadian cycle. This hormone acts systemically in numerous organs. In the brain, it is involved in the regulation of various neural and endocrine processes, and it readjusts the circadian pacemaker, the suprachiasmatic nucleus. This article reviews recent studies of gene organization, expression, evolution and mutations of melatonin receptor genes of vertebrates. Gene polymorphisms reveal that numerous mutations are associated with diseases and disorders. The phylogenetic analysis of receptor genes indicates that GPR50 is an outgroup to all other melatonin receptor sequences. GPR50 may have separated from a melatonin receptor ancestor before the split between MTNR1C and the MTNR1A/B ancestor.

  14. Mechanical stress regulates insulin sensitivity through integrin-dependent control of insulin receptor localization.

    Science.gov (United States)

    Kim, Jung; Bilder, David; Neufeld, Thomas P

    2018-01-15

    Insulin resistance, the failure to activate insulin signaling in the presence of ligand, leads to metabolic diseases, including type 2 diabetes. Physical activity and mechanical stress have been shown to protect against insulin resistance, but the molecular mechanisms remain unclear. Here, we address this relationship in the Drosophila larval fat body, an insulin-sensitive organ analogous to vertebrate adipose tissue and livers. We found that insulin signaling in Drosophila fat body cells is abolished in the absence of physical activity and mechanical stress even when excess insulin is present. Physical movement is required for insulin sensitivity in both intact larvae and fat bodies cultured ex vivo. Interestingly, the insulin receptor and other downstream components are recruited to the plasma membrane in response to mechanical stress, and this membrane localization is rapidly lost upon disruption of larval or tissue movement. Sensing of mechanical stimuli is mediated in part by integrins, whose activation is necessary and sufficient for mechanical stress-dependent insulin signaling. Insulin resistance develops naturally during the transition from the active larval stage to the immotile pupal stage, suggesting that regulation of insulin sensitivity by mechanical stress may help coordinate developmental programming with metabolism. © 2018 Kim et al.; Published by Cold Spring Harbor Laboratory Press.

  15. Dopamine D2 receptors in the pathophysiology of insulin resistance

    NARCIS (Netherlands)

    Leeuw van Weenen, Judith Elisabeth de

    2011-01-01

    Extensive literature links the dopamine receptor D2 to insulin resistance and diabetes mellitus type 2. However, many aspects of the functional relationship remain unclear. In this thesis we focused on unraveling the characteristics of the interplay between dopamine D2 receptors and glucose

  16. Phospholipid environment alters hormone-sensitivity of the purified insulin receptor kinase.

    OpenAIRE

    Lewis, R E; Czech, M P

    1987-01-01

    Insulin receptor kinase, affinity-purified by adsorption and elution from immobilized insulin, is stimulated 2-3-fold by insulin in detergent solution. Reconstitution of the receptor kinase into leaky vesicles containing phosphatidylcholine and phosphatidylethanolamine (1:1, w/w) by detergent removal on Sephadex G-50 results in the complete loss of receptor kinase sensitivity to activation by insulin. Insulin receptors in these vesicles also exhibit an increase in their apparent affinity for ...

  17. Rapid internalization of the insulin receptor in rat hepatoma cells

    International Nuclear Information System (INIS)

    Backer, J.M.; White, M.F.; Kahn, C.R.

    1987-01-01

    The authors have studied the internalization of the insulin receptor (IR) in rat hepatoma cells (Fao). The cells were surface-iodinated at 4 0 C, stimulated with insulin at 37 0 C, and then cooled rapidly, trypsinized at 4 0 C and solubilized. The IR was immunoprecipitated with a specific antibody, and internalization of the IR was assessed by the appearance of trypsin-resistant bands on SDS-PAGE. Insulin induced the internalization of surface receptors with a t 1/2 of 9-10 mins; cells not exposed to insulin internalized less than 20% of the IR during 1 h at 37 0 C. Further experiments demonstrated that the accumulation of trypsin-resistant IR paralleled a loss of receptor from the cell surface. Insulin-stimulated cells were chilled and iodinated at 4 0 C, followed by solubilization, immunoprecipitation and SDS-PAGE; alternatively, insulin-stimulated cells were chilled, surface-bound ligand removed by washing the cells at pH 4.2, and specific [ 125 I]insulin binding measured at 4 0 C. Both techniques confirmed the disappearance of IR from the cell surface at rates comparable to the insulin-stimulated internalization described above. The total amount of phosphotyrosine-containing IR, as assessed by immunoprecipitation with an anti-phosphotyrosine antibody, remained constant during this time interval, suggesting that active kinase is translocated into the cell. In summary, the authors data indicate that insulin binding increases the rate of IR internalization of Fao cells. This relocation may facilitate the interaction of the activated tyrosine kinase in the IR with intracellular substrates, thus transmitting the insulin signal to metabolic pathways

  18. Insulin receptor membrane retention by a traceable chimeric mutant

    OpenAIRE

    Giudice, Jimena; Jares, Elizabeth Andrea; Coluccio Leskow, Federico

    2015-01-01

    Background: The insulin receptor (IR) regulates glucose homeostasis, cell growth and differentiation. It has been hypothesized that the specific signaling characteristics of IR are in part determined by ligand-receptor complexes localization. Downstream signaling could be triggered from the plasma membrane or from endosomes. Regulation of activated receptor's internalization has been proposed as the mechanism responsible for the differential isoform and ligand-specific signaling. Re...

  19. Insulin-like growth factor II: complexity of biosynthesis and receptor binding

    DEFF Research Database (Denmark)

    Gammeltoft, S; Christiansen, Jan; Nielsen, F C

    1991-01-01

    Insulin-like growth factor II (IGF-II) belongs to the insulin family of peptides and acts as a growth factor in many fetal tissues and tumors. The gene expression of IGF-II is initiated at three different promoters which gives rise to multiple transcripts. In a human rhabdomyosarcoma cell line......, Man-6-P induces cellular responses. We have studied rat brain neuronal precursor cells where Man-6-P acted as a mitogen suggesting that phosphomannosylated proteins may act as growth factors via the Man-6-P/IGF-II receptor. In conclusion, the gene expression and mechanism of action of IGF-II is very...

  20. Insulin-receptors in diabetes and altered thyroidal status

    International Nuclear Information System (INIS)

    Chaujar, Meena; Subramanian, G.B.V.; Yadav, H.S.; Chauhan, U.P.S.

    1991-01-01

    Rats were made hypothyroid by treating with a single dose of 800 μCi of 131 I and hyperthyroid condition was created by administering 90 μg of thyroxine daily for 2 weeks. Diabetes was produced by administering single dose of alloxan monohydrate. Hypothyroid rats showed significant increase in 125 I-insulin binding with its liver plasma membrane receptors with respect to normal rats. In the case of hypothyroid diabetic rats such binding was greater as compared to hypothyroid rats without diabetes. Hyperthyroid rats with respect to normal control rats showed a decrease in 125 I-insulin binding to its liver plasma membrane receptors. When hyperthyroid rats were made diabetic, 125 I-insulin binding to its receptors was further decreased. The study infers that hyper-thyrodism further decreases insulin binding to its receptors which has already been decreased in diabetes. Hypothyroidism, on the other hand, improves upon the decreased insulin binding to its receptors in diabetes. (author). 16 refs., 6 figs., 2 tabs

  1. Light regulation of the insulin receptor in the retina.

    Science.gov (United States)

    Rajala, Raju V S; Anderson, Robert E

    2003-10-01

    The peptide hormone insulin binds its cognate cell-surface receptors to activate a coordinated biochemical-signaling network and to induce intracellular events. The retina is an integral part of the central nervous system and is known to contain insulin receptors, although their function is unknown. This article, describes recent studies that link the photobleaching of rhodopsin to tyrosine phosphorylation of the insulin receptor and subsequent activation of phosphoinositide 3- kinase (PI3K). We recently found a light-dependent increase in tyrosine phosphorylation of the insulin receptor-beta-subunit (IR beta) and an increase in PI3K enzyme activity in isolated rod outer segments (ROS) and in anti-phosphotyrosine (PY) and anti-IR beta immunoprecipitates of retinal homogenates. The light effect, which was localized to photoreceptor neurons, is independent of insulin secretion. Our results suggest that light induces tyrosine phosphorylation of IR beta in outer-segment membranes, which leads to the binding of p85 through its N-terminal SH2 domain and the generation of PI-3,4,5-P3. We suggest that the physiological role of this process may be to provide neuroprotection of the retina against light damage by activating proteins that protect against stress-induced apoptosis. The studies linking PI3K activation through tyrosine phosphorylation of IR beta now provide physiological relevance for the presence of these receptors in the retina.

  2. Binding Mode of Insulin Receptor and Agonist Peptide

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Insulin is a protein hormone secreted by pancreatic β cells. One of its main functions is to keep the balance of glucose inside the body by regulating the absorption and metabolism of glucose in the periphery tissue, as well as the production and storage of hepatic glycogen. The insulin receptor is a transmembrane glycoprotein in which two α subunits with a molecular weight of 135 kD and twoβ subunits with a molecular weight of 95 kD are joined by a disulfide bond to form a β-α-α-β structure. The extracellular α subunit, especially, its three domains near the N-terminal are partially responsible for signal transduction or ligand-binding, as indicated by the experiments. The extracellular α subunits are involved in binding the ligands. The experimental results indicate that the three domains of the N-terminal of the α subunits are the main determinative parts of the insulin receptor to bind the insulin or mimetic peptide.We employed the extracellular domain (PDBID: 1IGR) of the insulin-like growth factor-1 receptor (IGF-1 R ) as the template to simulate and optimize the spatial structures of the three domains in the extracellular domain of the insulin receptor, which includes 468 residues. The work was accomplished by making use of the homology program in the Insight Ⅱ package on an Origin3800 server. The docking calculations of the insulin receptor obtained by homology with hexapeptides were carried out by means of the program Affinity. The analysis indicated that there were hydrogen bonding, and electrostatic and hydrophobic effects in the docking complex of the insulin receptor with hexapeptides.Moreover, we described the spatial orientation of a mimetic peptide with agonist activity in the docking complex. We obtained a rough model of binding of DLAPSQ or STIVYS with the insulin receptor, which provides the powerful theoretical support for designing the minimal insulin mimetic peptide with agonist activity, making it possible to develop oral small

  3. Interacting with the Human Insulin Receptor

    DEFF Research Database (Denmark)

    Kidmose, Rune Thomas; Andersen, Gregers Rom

    2016-01-01

    Insulin is an essential regulator of glucose homeostasis. In this issue of Structure, Croll et al. (2016) reports a significantly improved model of the Fab-complexed IR ectodomain refined against a dataset extending to 3.3 Å.......Insulin is an essential regulator of glucose homeostasis. In this issue of Structure, Croll et al. (2016) reports a significantly improved model of the Fab-complexed IR ectodomain refined against a dataset extending to 3.3 Å....

  4. Studies on interaction of insulin and insulin receptor in rat liver cell membranes

    Energy Technology Data Exchange (ETDEWEB)

    Sakai, Y; Hara, H; Kawate, R; Kawasaki, T [Hiroshima Univ. (Japan). School of Medicine

    1975-07-01

    Rat liver was homogenized with a Polytron PT 20 ST and fractionated by differential centrifugation. Prepared plasma membranes (100 ..mu..g protein) were incubated with enzymatically iodinated /sup 125/I-insulin (0.3 ng, specific activity 107 ..mu..Ci/..mu..g) in 25 mM Tris-HCl buffer, pH 7.5, containing 0.9% NaCl and 1% bovine serum albumin. The 12,000xg- and 17,000xg-sediments obtained after subfractionation of liver homogenates showed almost equally high specific binding activity with /sup 125/I-insulin and less activity was detected in the 600 g-, 5,000 g- and 40,000 g- sediments and the 40,000 g- supernatant. Specific binding of insulin with the membrane fraction was time-, temperature- and ionic strength-dependent. The highest binding was obtained under conditions in which the membrane fraction was incubated with insulin for 24 hours at 4/sup 0/C in the buffer containing 1 M NaCl. Under these conditions, specific binding of /sup 125/I-insulin was 26.8% of the total radioactivity. The effect of native insulin on the binding of /sup 125/I-insulin with the membrane fraction was studied in the range of 0--6.4 x 10/sup 5/ ..mu..U/ml of unlabeled insulin and a distinct competitive displacement of /sup 125/I-insulin with native insulin was observed between 10 and 10/sup 4/ ..mu..U/ml. Kinetic studies by Scatchard plot analysis of the above results revealed heterogeneity in insulin receptors or receptor sites, one with a high affinity of 10/sup 9/ M/sup -1/ order and the other with a low affinity of 10/sup 8/ M/sup -1/ order. Both affinities were also affected by temperature and ionic strength.

  5. Fundamental studies on the insulin receptor in rabbit erythrocytes

    Energy Technology Data Exchange (ETDEWEB)

    Shinomiya, Y; Kagawa, S; Konishi, Y; Morimoto, H; Tsumura, Y [Hyogo Medical Coll. (Japan)

    1975-09-01

    The authors studied the binding of insulin to rabbit erythrocytes as a mode case in the hope of characterizing the physiologic role of the binding of insulin to receptor in both normal adults and patients. Specific binding sites for insulin were detected in rabbit erythrocytes. The characteristics of the binding were similar to those observed in other target tissues. The specific binding of /sup 125/I-labeled insulin was competitively inhibited by a small amount of unlabeled insulin and was completely inhibited by 1,000 ng/ml of unlabeled insulin. Glucagon, however, had no effect on the insulin binding to fat cells or liver membranes nor had it any effect on the binding of insulin to rabbit erythrocytes. Scatchard analysis of this binding reaction indicated two different binding sites with Ksub(aff)=3.2 x 10/sup 8//M, Ksub(diss)=3.1 x 10/sup -9/M; Ksub(aff)=1.4 x 10/sup 8//M, Ksub(diss)=7.1 x 10/sup -9/M respectively, and the binding capacities of each site were estimated at 0.011 ng/4 x 10/sup 8/ cells and 0.138 ng/4 x 10/sup 8/ cells. The binding of /sup 125/I-insulin to rabbit erythrocytes was a saturable function of the insulin concentration and was a linear function of cell concentration. The pH optimum for the reaction was 7.4 at 0/sup 0/C, the amount of insulin binding increased continuously under the reaction and this binding reaction reached a steady state after 10 to 15hr. On the other hand, the specific binding of insulin at higher temperatures showed maximal amounts after 20 to 30 min. and subsequently fell off at later time points.

  6. Signal transduction through the IL-4 and insulin receptor families.

    Science.gov (United States)

    Wang, L M; Keegan, A; Frankel, M; Paul, W E; Pierce, J H

    1995-07-01

    Activation of tyrosine kinase-containing receptors and intracellular tyrosine kinases by ligand stimulation is known to be crucial for mediating initial and subsequent events involved in mitogenic signal transduction. Receptors for insulin and insulin-like growth factor 1 (IGF-1) contain cytoplasmic tyrosine kinase domains that undergo autophosphorylation upon ligand stimulation. Activation of these receptors also leads to pronounced and rapid tyrosine phosphorylation of insulin receptor substrate 1 (IRS-1) in cells of connective tissue origin. A related substrate, designated 4PS, is similarly phosphorylated by insulin and IGF-1 stimulation in many hematopoietic cell types. IRS-1 and 4PS possess a number of tyrosine phosphorylation sites that are within motifs that bind specific SH2-containing molecules known to be involved in mitogenic signaling such as PI-3 kinase, SHPTP-2 (Syp) and Grb-2. Thus, they appear to act as docking substrates for a variety of signaling molecules. The majority of hematopoietic cytokines bind to receptors that do not possess intrinsic kinase activity, and these receptors have been collectively termed as members of the hematopoietin receptor superfamily. Despite their lack of tyrosine kinase domains, stimulation of these receptors has been demonstrated to activate intracellular kinases leading to tyrosine phosphorylation of multiple substrates. Recent evidence has demonstrated that activation of different members of the Janus family of tyrosine kinases is involved in mediating tyrosine phosphorylation events by specific cytokines. Stimulation of the interleukin 4 (IL-4) receptor, a member of the hematopoietin receptor superfamily, is thought to result in activation of Jak1, Jak3, and/or Fes tyrosine kinases.(ABSTRACT TRUNCATED AT 250 WORDS)

  7. Insulin receptor substrates 1 and 2 but not Shc can activate the insulin receptor independent of insulin and induce proliferation in CHO-IR cells

    International Nuclear Information System (INIS)

    Niessen, Markus; Jaschinski, Frank; Item, Flurin; McNamara, Morgan P.; Spinas, Giatgen A.; Trueb, Thomas

    2007-01-01

    Ligand-activated insulin receptor (IR) attracts and phosphorylates various substrates such as insulin receptor substrates 1-4 (IRS) and Shc. To investigate how binding affinity for substrate affects signalling we generated chimeric receptors with the β-chain of the insulin receptor containing NPXY motives with different affinities for receptor substrates. We found that the extent of receptor tyrosine phosphorylation positively correlates with binding affinity towards IRS1/2 but not towards Shc. Moreover, overexpression of IRS1 or IRS2 but not of Shc increased IR tyrosine phosphorylation in a dose-dependent manner, also independent of insulin. Molecular truncations of IRS1 revealed that neither the isolated PH and PTB domains nor the C-terminus with the tyrosine phosphorylation sites alone are sufficient for substrate-dependent receptor activation. Overexpression of IRS1 and IRS2 impaired insulin-induced internalization of the IR in a dose-dependent manner suggesting that IRS proteins prevent endosome-associated receptor dephosphorylation/inactivation. IRS1 and IRS2 could therefore target the activated IR to different cellular compartments. Overexpression of IRS1 and IRS2 inhibited insulin-stimulated activation of the MAP kinases Erk1/2 while it increased/induced activation of Akt/PKB. Finally, overexpression of IRS1 and IRS2 but not of Shc induced DNA synthesis in starved CHO-IR cells independent of exogenous growth factors. Our results demonstrate that variations in cellular IRS1 and IRS2 concentration affect insulin signalling both upstream and downstream and that IRS proteins could play instructive rather than just permissive roles in signal transmission

  8. Binding of the Ras activator son of sevenless to insulin receptor substrate-1 signaling complexes.

    Science.gov (United States)

    Baltensperger, K; Kozma, L M; Cherniack, A D; Klarlund, J K; Chawla, A; Banerjee, U; Czech, M P

    1993-06-25

    Signal transmission by insulin involves tyrosine phosphorylation of a major insulin receptor substrate (IRS-1) and exchange of Ras-bound guanosine diphosphate for guanosine triphosphate. Proteins containing Src homology 2 and 3 (SH2 and SH3) domains, such as the p85 regulatory subunit of phosphatidylinositol-3 kinase and growth factor receptor-bound protein 2 (GRB2), bind tyrosine phosphate sites on IRS-1 through their SH2 regions. Such complexes in COS cells were found to contain the heterologously expressed putative guanine nucleotide exchange factor encoded by the Drosophila son of sevenless gene (dSos). Thus, GRB2, p85, or other proteins with SH2-SH3 adapter sequences may link Sos proteins to IRS-1 signaling complexes as part of the mechanism by which insulin activates Ras.

  9. Insulin Receptor Substrate 2 Is a Negative Regulator of Memory Formation

    Science.gov (United States)

    Irvine, Elaine E.; Drinkwater, Laura; Radwanska, Kasia; Al-Qassab, Hind; Smith, Mark A.; O'Brien, Melissa; Kielar, Catherine; Choudhury, Agharul I.; Krauss, Stefan; Cooper, Jonathan D.; Withers, Dominic J.; Giese, Karl Peter

    2011-01-01

    Insulin has been shown to impact on learning and memory in both humans and animals, but the downstream signaling mechanisms involved are poorly characterized. Insulin receptor substrate-2 (Irs2) is an adaptor protein that couples activation of insulin- and insulin-like growth factor-1 receptors to downstream signaling pathways. Here, we have…

  10. Interaction between the p21ras GTPase activating protein and the insulin receptor

    NARCIS (Netherlands)

    Pronk, G.J.; Medema, R.H.; Burgering, B.M.T.; Clark, R.; McCormick, F.; Bos, J.L.

    1992-01-01

    We investigated the involvement of the p21ras-GTPase activating protein (GAP) in insulin-induced signal transduction. In cells overexpressing the insulin receptor, we did not observe association between GAP and the insulin receptor after insulin treatment nor the phosphorylation of GAP on tyrosine

  11. Dithiothreitol activation of the insulin receptor/kinase does not involve subunit dissociation of the native α2β2 insulin receptor subunit complex

    International Nuclear Information System (INIS)

    Sweet, L.J.; Wilden, P.A.; Pessin, J.E.

    1986-01-01

    The subunit composition of the dithiothreitol- (DTT) activated insulin receptor/kinase was examined by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis and gel filtration chromatography under denaturing or nondenaturing conditions. Pretreatment of 32 P-labeled insulin receptors with 50 mM DTT followed by gel filtration chromatography in 0.1% SDS demonstrated the dissociation of the α 2 β 2 insulin receptor complex (M/sub r/ 400,000) into the monomeric 95,000 β subunit. In contrast, pretreatment of the insulin receptors with 1-50 mM DTT followed by gel filtration chromatography in 0.1% Triton X-100 resulted in no apparent alteration in mobility compared to the untreated insulin receptors. Resolution of this complex by nonreducing SDS-polyacrylamide gel electrophoresis and autoradiography demonstrated the existence of the α 2 β 2 heterotetrameric complex with essentially no αβ heterodimeric or free monomeric β subunit species present. This suggests that the insulin receptor can reoxidize into the M/sub r/ 400,000 complex after the removal of DTT by gel filtration chromatography. To prevent reoxidation, the insulin receptors were pretreated with 50 mM DTT. Under the conditions the insulin receptors migrated as the M/sub r/ 400,000 α 2 β 2 complex. These results demonstrate that treatment of the insulin receptors with high concentrations of DTT, followed by removal of DTT by gel filtration, results in reoxidation of the reduced α 2 β 2 insulin receptor complex. Further, these results document that although the DTT stimulation of the insulin receptor/kinase does involve reduction of the insulin receptor subunits, it does not result in dissociation of the native α 2 β 2 insulin receptor subunit complex

  12. The macrophage A2B adenosine receptor regulates tissue insulin sensitivity.

    Directory of Open Access Journals (Sweden)

    Hillary Johnston-Cox

    Full Text Available High fat diet (HFD-induced type 2 diabetes continues to be an epidemic with significant risk for various pathologies. Previously, we identified the A2b adenosine receptor (A2bAR, an established regulator of inflammation, as a regulator of HFD-induced insulin resistance. In particular, HFD was associated with vast upregulation of liver A2bAR in control mice, and while mice lacking this receptor showed augmented liver inflammation and tissue insulin resistance. As the A2bAR is expressed in different tissues, here, we provide the first lead to cellular mechanism by demonstrating that the receptor's influence on tissue insulin sensitivity is mediated via its expression in macrophages. This was shown using a newly generated transgenic mouse model expressing the A2bAR gene in the macrophage lineage on an otherwise A2bAR null background. Reinstatement of macrophage A2bAR expression in A2bAR null mice fed HFD restored insulin tolerance and tissue insulin signaling to the level of control mice. The molecular mechanism for this effect involves A2bAR-mediated changes in cyclic adenosine monophosphate in macrophages, reducing the expression and release of inflammatory cytokines, which downregulate insulin receptor-2. Thus, our results illustrate that macrophage A2bAR signaling is needed and sufficient for relaying the protective effect of the A2bAR against HFD-induced tissue inflammation and insulin resistance in mice.

  13. Mechanical stretch augments insulin-induced vascular smooth muscle cell proliferation by insulin-like growth factor-1 receptor

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Gang [Department of Pharmacology, Faculty of Medicine, Kagawa University, Kagawa (Japan); Department of Anesthesiology, First Affiliated Hospital of China Medical University, Shenyang (China); Hitomi, Hirofumi, E-mail: hitomi@kms.ac.jp [Department of Pharmacology, Faculty of Medicine, Kagawa University, Kagawa (Japan); Hosomi, Naohisa [Department of Cardiorenal and Cerebrovascular Medicine, Faculty of Medicine, Kagawa University, Kagawa (Japan); Lei, Bai; Nakano, Daisuke [Department of Pharmacology, Faculty of Medicine, Kagawa University, Kagawa (Japan); Deguchi, Kazushi; Mori, Hirohito; Masaki, Tsutomu [Department of Gastroenterology and Neurology, Faculty of Medicine, Kagawa University, Kagawa (Japan); Ma, Hong [Department of Anesthesiology, First Affiliated Hospital of China Medical University, Shenyang (China); Griendling, Kathy K. [Department of Medicine, Division of Cardiology, Emory University School of Medicine, Atlanta, GA (United States); Nishiyama, Akira [Department of Pharmacology, Faculty of Medicine, Kagawa University, Kagawa (Japan)

    2011-10-15

    Insulin resistance and hypertension have been implicated in the pathogenesis of cardiovascular disease; however, little is known about the roles of insulin and mechanical force in vascular smooth muscle cell (VSMC) remodeling. We investigated the contribution of mechanical stretch to insulin-induced VSMC proliferation. Thymidine incorporation was stimulated by insulin in stretched VSMCs, but not in un-stretched VSMCs. Insulin increased 2-deoxy-glucose incorporation in both stretched and un-stretched VSMCs. Mechanical stretch augmented insulin-induced extracellular signal-regulated kinase (ERK) and Akt phosphorylation. Inhibitors of epidermal growth factor (EGF) receptor tyrosine kinase and Src attenuated insulin-induced ERK and Akt phosphorylation, as well as thymidine incorporation, whereas 2-deoxy-glucose incorporation was not affected by these inhibitors. Moreover, stretch augmented insulin-like growth factor (IGF)-1 receptor expression, although it did not alter the expression of insulin receptor and insulin receptor substrate-1. Insulin-induced ERK and Akt activation, and thymidine incorporation were inhibited by siRNA for the IGF-1 receptor. Mechanical stretch augments insulin-induced VSMC proliferation via upregulation of IGF-1 receptor, and downstream Src/EGF receptor-mediated ERK and Akt activation. Similar to in vitro experiment, IGF-1 receptor expression was also augmented in hypertensive rats. These results provide a basis for clarifying the molecular mechanisms of vascular remodeling in hypertensive patients with hyperinsulinemia. -- Highlights: {yields} Mechanical stretch augments insulin-induced VSMC proliferation via IGF-1 receptor. {yields} Src/EGFR-mediated ERK and Akt phosphorylation are augmented in stretched VSMCs. {yields} Similar to in vitro experiment, IGF-1 receptor is increased in hypertensive rats. {yields} Results provide possible mechanisms of vascular remodeling in hypertension with DM.

  14. A bioluminescence resonance energy transfer 2 (BRET2) assay for monitoring seven transmembrane receptor and insulin receptor crosstalk

    DEFF Research Database (Denmark)

    Sanni, Samra Joke; Kulahin, Nikolaj; Jorgensen, Rasmus

    2017-01-01

    The angiotensin AT1 receptor is a seven transmembrane (7TM) receptor, which mediates the regulation of blood pressure. Activation of angiotensin AT1 receptor may lead to impaired insulin signaling indicating crosstalk between angiotensin AT1 receptor and insulin receptor signaling pathways....... To elucidate the molecular mechanisms behind this crosstalk, we applied the BRET2 technique to monitor the effect of angiotensin II on the interaction between Rluc8 tagged insulin receptor and GFP2 tagged insulin receptor substrates 1, 4, 5 (IRS1, IRS4, IRS5) and Src homology 2 domain-containing protein (Shc......). We demonstrate that angiotensin II reduces the interaction between insulin receptor and IRS1 and IRS4, respectively, while the interaction with Shc is unaffected, and this effect is dependent on Gαq activation. Activation of other Gαq-coupled 7TM receptors led to a similar reduction in insulin...

  15. Identification and characterization of insulin receptors on foetal-mouse brain-cortical cells.

    OpenAIRE

    Van Schravendijk, C F; Hooghe-Peters, E L; De Meyts, P; Pipeleers, D G

    1984-01-01

    The occurrence of insulin receptors was investigated in freshly dissociated brain-cortical cells from mouse embryos. By analogy with classical insulin-binding cell types, binding of 125I-insulin to foetal brain-cortical cells was time- and pH-dependent, only partially reversible, and competed for by unlabelled insulin and closely related peptides. Desalanine-desasparagine-insulin, pig proinsulin, hagfish insulin and turkey insulin were respectively 2%, 4%, 2% and 200% as potent as bovine insu...

  16. Cloning and characterisation of Schistosoma japonicum insulin receptors.

    Directory of Open Access Journals (Sweden)

    Hong You

    2010-03-01

    Full Text Available Schistosomes depend for growth and development on host hormonal signals, which may include the insulin signalling pathway. We cloned and assessed the function of two insulin receptors from Schistosoma japonicum in order to shed light on their role in schistosome biology.We isolated, from S. japonicum, insulin receptors 1 (SjIR-1 and 2 (SjIR-2 sharing close sequence identity to their S. mansoni homologues (SmIR-1 and SmIR-2. SjIR-1 is located on the tegument basal membrane and the internal epithelium of adult worms, whereas SjIR-2 is located in the parenchyma of males and the vitelline tissue of females. Phylogenetic analysis showed that SjIR-2 and SmIR-2 are close to Echinococcus multilocularis insulin receptor (EmIR, suggesting that SjIR-2, SmIR-2 and EmIR share similar roles in growth and development in the three taxa. Structure homology modelling recovered the conserved structure between the SjIRs and Homo sapiens IR (HIR implying a common predicted binding mechanism in the ligand domain and the same downstream signal transduction processing in the tyrosine kinase domain as in HIR. Two-hybrid analysis was used to confirm that the ligand domains of SjIR-1 and SjIR-2 contain the insulin binding site. Incubation of adult worms in vitro, both with a specific insulin receptor inhibitor and anti-SjIRs antibodies, resulted in a significant decrease in worm glucose levels, suggesting again the same function for SjIRs in regulating glucose uptake as described for mammalian cells.Adult worms of S. japonicum possess insulin receptors that can specifically bind to insulin, indicating that the parasite can utilize host insulin for development and growth by sharing the same pathway as mammalian cells in regulating glucose uptake. A complete understanding of the role of SjIRs in the biology of S. japonicum may result in their use as new targets for drug and vaccine development against schistosomiasis.

  17. Association between Single Nucleotide Polymorphisms in Gamma-Aminobutyric Acid B Receptor, Insulin Receptor Substrate-1, and Hypocretin Neuropeptide Precursor Genes and Susceptibility to Obstructive Sleep Apnea Hypopnea Syndrome in a Chinese Han Population.

    Science.gov (United States)

    Li, Zhijun; Tang, Tingyu; Du, Jianzong; Wu, Wenjuan; Zhou, Xiaoxi; Qin, Guangyue

    2016-01-01

    To investigate genotype-phenotype changes between rs29230 in γ-aminobutyric acid B receptor (GABBR1), rs1801278 in insulin receptor substrate-1 (IRS-1), and rs9902709 in hypocretin neuropeptide precursor (HCRT) and obstructive sleep apnea hypopnea syndrome (OSAHS) in Chinese Han individuals. A total of 130 patients with OSAHS and 136 age- and gender-matched healthy controls were enrolled in this study. A brief description of DNA extraction and genotyping is given. Multivariate unconditional logistic regression analysis adjusted for gender and age was used to estimate the associations of single nucleotide polymorphisms (SNPs) rs29230 (GABBR1), rs1801278 (IRS-1), and rs9902709 (HCRT) with OSAHS risk. Subgroup analysis was performed to evaluate differences in these SNPs among subgroups according to gender, body mass index (BMI), and severity of disease. Genotype and allele frequencies of rs29230 were significantly different between cases and controls (p = 0.0205 and p = 0.0191, respectively; odds ratio = 0.493, 95% confidence interval = 0.271-0.896), especially for male patients (p = 0.0259 and p = 0.0202, respectively). Subgroup analysis according to BMI also revealed a significant allele difference for rs29230 between cases and controls in the overweight subgroup (p = 0.0333). Furthermore, allele and genotype frequencies of rs1801278 showed significant differences between cases and controls (p = 0.0488 and p = 0.0471, respectively). However, no association was observed between rs9902709 and OSAHS risk (p = 0.2762), and no differences were identified in other subgroups. In this study, there was an association between variants of rs29230 and rs1801278 and OSAHS risk in the Chinese Han population but not for rs9902709. © 2016 S. Karger AG, Basel.

  18. Insulin receptor substrate-3, interacting with Bcl-3, enhances p50 NF-{kappa}B activity

    Energy Technology Data Exchange (ETDEWEB)

    Kabuta, Tomohiro [Departments of Animal Sciences and Applied Biological Chemistry, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Tokyo 113-8657 (Japan); Department of Degenerative Neurological Diseases, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Tokyo 187-8502 (Japan); Hakuno, Fumihiko; Cho, Yoshitake; Yamanaka, Daisuke; Chida, Kazuhiro [Departments of Animal Sciences and Applied Biological Chemistry, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Tokyo 113-8657 (Japan); Asano, Tomoichiro [Graduate School of Biomedical Science, Hiroshima University, Hiroshima 734-8551 (Japan); Wada, Keiji [Department of Degenerative Neurological Diseases, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Tokyo 187-8502 (Japan); Takahashi, Shin-Ichiro, E-mail: atkshin@mail.ecc.u-tokyo.ac.jp [Departments of Animal Sciences and Applied Biological Chemistry, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Tokyo 113-8657 (Japan)

    2010-04-09

    The insulin receptor substrate (IRS) proteins are major substrates of both insulin receptor and insulin-like growth factor (IGF)-I receptor tyrosine kinases. Previously, we reported that IRS-3 is localized to both cytosol and nucleus, and possesses transcriptional activity. In the present study, we identified Bcl-3 as a novel binding protein to IRS-3. Bcl-3 is a nuclear protein, which forms a complex with the homodimer of p50 NF-{kappa}B, leading to enhancement of transcription through p50 NF-{kappa}B. We found that Bcl-3 interacts with the pleckstrin homology domain and the phosphotyrosine binding domain of IRS-3, and that IRS-3 interacts with the ankyrin repeat domain of Bcl-3. In addition, IRS-3 augmented the binding activity of p50 to the NF-{kappa}B DNA binding site, as well as the tumor necrosis factor (TNF)-{alpha}-induced transcriptional activity of NF-{kappa}B. Lastly, IRS-3 enhanced NF-{kappa}B-dependent anti-apoptotic gene induction and consequently inhibited TNF-{alpha}-induced cell death. This series of results proposes a novel function for IRS-3 as a transcriptional regulator in TNF-{alpha} signaling, distinct from its function as a substrate of insulin/IGF receptor kinases.

  19. How insulin engages its primary binding site on the insulin receptor

    Czech Academy of Sciences Publication Activity Database

    Menting, J. G.; Whittaker, J.; Margetts, M. B.; Whittaker, L. J.; Kong, G. K. W.; Smith, B. J.; Watson, C. J.; Žáková, Lenka; Kletvíková, Emília; Jiráček, Jiří; Chan, S. J.; Steiner, D. F.; Dodson, G. G.; Brzozowski, A. M.; Weiss, M. A.; Ward, C. W.; Lawrence, M. C.

    2013-01-01

    Roč. 493, č. 7431 (2013), s. 241-245 ISSN 0028-0836 R&D Projects: GA ČR GPP207/11/P430 Institutional support: RVO:61388963 Keywords : insulin * receptor * complex * crystal structure Subject RIV: CE - Biochemistry Impact factor: 42.351, year: 2013

  20. Alternative translation initiation of Caveolin-2 desensitizes insulin signaling through dephosphorylation of insulin receptor by PTP1B and causes insulin resistance.

    Science.gov (United States)

    Kwon, Hayeong; Jang, Donghwan; Choi, Moonjeong; Lee, Jaewoong; Jeong, Kyuho; Pak, Yunbae

    2018-06-01

    Insulin resistance, defined as attenuated sensitivity responding to insulin, impairs insulin action. Direct causes and molecular mechanisms of insulin resistance have thus far remained elusive. Here we show that alternative translation initiation (ATI) of Caveolin-2 (Cav-2) regulates insulin sensitivity. Cav-2β isoform yielded by ATI desensitizes insulin receptor (IR) via dephosphorylation by protein-tyrosine phosphatase 1B (PTP1B), and subsequent endocytosis and lysosomal degradation of IR, causing insulin resistance. Blockage of Cav-2 ATI protects against insulin resistance by preventing Cav-2β-PTP1B-directed IR desensitization, thereby normalizing insulin sensitivity and glucose uptake. Our findings show that Cav-2β is a negative regulator of IR signaling, and identify a mechanism causing insulin resistance through control of insulin sensitivity via Cav-2 ATI. Copyright © 2018 Elsevier B.V. All rights reserved.

  1. Correlation Analysis Between Expression Levels of Hepatic Growth Hormone Receptor, Janus Kinase 2, Insulin-Like Growth Factor-I Genes and Dwarfism Phenotype in Bama Minipig.

    Science.gov (United States)

    Yang, Haowen; Jiang, Qinyang; Wu, Dan; Lan, Ganqiu; Fan, Jing; Guo, Yafen; Chen, Baojian; Yang, Xiurong; Jiang, Hesheng

    2015-02-01

    Animal growth and development are complex and sophisticated biological metabolic processes, in which genes plays an important role. In this paper, we employed real-time quantitative PCR (RT-qPCR) to analyze the expression levels of hepatic GHR, JAK2 and IGF-I genes in 1, 30, 180 day of Bama minipig and Landrace with attempt to verify the correlation between the expression of these growth-associated genes and the dwarfism phenotype of Bama minipig. The results showed that the expression levels of these 3 genes in Bama minipigs were down-regulated expressed from 1 day to 30 day, and which was up-regulated expressed in Landrace. The expression levels of the 3 genes on 1, 30, 180 day were prominently higher in Landrace than in Bama minipigs. The significant differences of the 3 genes expression levels on 1 day between this two breeds indicate that different expressions of these genes might occur before birth. It is speculated that the down-regulated expression of the 3 genes may have a close correlation with the dwarfism phenotype of Bama minipig. More investigations in depth of this study is under progress with the help of biochip nanotechnology.

  2. Insulin Resistance Induced by Hyperinsulinemia Coincides with a Persistent Alteration at the Insulin Receptor Tyrosine Kinase Domain

    Science.gov (United States)

    Catalano, Karyn J.; Maddux, Betty A.; Szary, Jaroslaw; Youngren, Jack F.; Goldfine, Ira D.; Schaufele, Fred

    2014-01-01

    Insulin resistance, the diminished response of target tissues to insulin, is associated with the metabolic syndrome and a predisposition towards diabetes in a growing proportion of the worldwide population. Under insulin resistant states, the cellular response of the insulin signaling pathway is diminished and the body typically responds by increasing serum insulin concentrations to maintain insulin signaling. Some evidence indicates that the increased insulin concentration may itself further dampen insulin response. If so, insulin resistance would worsen as the level of circulating insulin increases during compensation, which could contribute to the transition of insulin resistance to more severe disease. Here, we investigated the consequences of excess insulin exposure to insulin receptor (IR) activity. Cells chronically exposed to insulin show a diminished the level of IR tyrosine and serine autophosphorylation below that observed after short-term insulin exposure. The diminished IR response did not originate with IR internalization since IR amounts at the cell membrane were similar after short- and long-term insulin incubation. Förster resonance energy transfer between fluorophores attached to the IR tyrosine kinase (TK) domain showed that a change in the TK domain occurred upon prolonged, but not short-term, insulin exposure. Even though the altered ‘insulin refractory’ IR TK FRET and IR autophosphorylation levels returned to baseline (non-stimulated) levels after wash-out of the original insulin stimulus, subsequent short-term exposure to insulin caused immediate re-establishment of the insulin-refractory levels. This suggests that some cell-based ‘memory’ of chronic hyperinsulinemic exposure acts directly at the IR. An improved understanding of that memory may help define interventions to reset the IR to full insulin responsiveness and impede the progression of insulin resistance to more severe disease states. PMID:25259572

  3. Insulin resistance induced by hyperinsulinemia coincides with a persistent alteration at the insulin receptor tyrosine kinase domain.

    Directory of Open Access Journals (Sweden)

    Karyn J Catalano

    Full Text Available Insulin resistance, the diminished response of target tissues to insulin, is associated with the metabolic syndrome and a predisposition towards diabetes in a growing proportion of the worldwide population. Under insulin resistant states, the cellular response of the insulin signaling pathway is diminished and the body typically responds by increasing serum insulin concentrations to maintain insulin signaling. Some evidence indicates that the increased insulin concentration may itself further dampen insulin response. If so, insulin resistance would worsen as the level of circulating insulin increases during compensation, which could contribute to the transition of insulin resistance to more severe disease. Here, we investigated the consequences of excess insulin exposure to insulin receptor (IR activity. Cells chronically exposed to insulin show a diminished the level of IR tyrosine and serine autophosphorylation below that observed after short-term insulin exposure. The diminished IR response did not originate with IR internalization since IR amounts at the cell membrane were similar after short- and long-term insulin incubation. Förster resonance energy transfer between fluorophores attached to the IR tyrosine kinase (TK domain showed that a change in the TK domain occurred upon prolonged, but not short-term, insulin exposure. Even though the altered 'insulin refractory' IR TK FRET and IR autophosphorylation levels returned to baseline (non-stimulated levels after wash-out of the original insulin stimulus, subsequent short-term exposure to insulin caused immediate re-establishment of the insulin-refractory levels. This suggests that some cell-based 'memory' of chronic hyperinsulinemic exposure acts directly at the IR. An improved understanding of that memory may help define interventions to reset the IR to full insulin responsiveness and impede the progression of insulin resistance to more severe disease states.

  4. Nature and regulation of the receptors for insulin-like growth factors

    International Nuclear Information System (INIS)

    Rechler, M.M.; Nissley, S.P.

    1985-01-01

    Two subtypes of IGF receptors have been identified. Type I IGF receptors have a Mr greater than 300,000 and are composed of disulfide-linked 130,000-dalton (alpha) and approximately 90,000-dalton (beta) subunits. Type I receptors preferentially bind IGF-I but also bind IGF-II and, more weakly, insulin. Type II IGF receptors consist of a 250,000-dalton protein that contains internal disulfide bonds but is not linked to other membrane components. Type II receptors bind IGF-II with higher affinity than IGF-I. They do not interact with even very high concentrations of insulin. Type I IGF receptors and insulin receptors are homologous structures. Type II IGF receptors do not appear to be homologous to type I receptors. Type II receptors do not appear to be downregulated. Insulin acutely upregulates type II IGF receptors in intact rat adipose cells by effecting a redistribution of receptors cycling between a large intracellular pool and the plasma membrane. Insulin and the IGFs elicit the same biological responses, either by cross-reacting with one of the receptors for the heterologous ligand or by concurrent activation of convergent effector pathways by binding to the homologous receptor. Which mechanism is utilized appears to depend more on the tissue than on the biological response. Insulin desensitizes rat hepatoma cells to the actions of insulin and IGFs, mediated by both insulin and IGF receptors, by mechanisms distal to hormone binding and possibly common to IGF and insulin effector pathways

  5. Insulin and insulin-like growth factor receptors in the brain: physiological and pathological aspects.

    Science.gov (United States)

    Werner, Haim; LeRoith, Derek

    2014-12-01

    The involvement of insulin, the insulin-like growth factors (IGF1, IGF2) and their receptors in central nervous system development and function has been the focus of scientific interest for more than 30 years. The insulin-like peptides, both locally-produced proteins as well as those transported from the circulation into the brain via the blood-brain barrier, are involved in a myriad of biological activities. These actions include, among others, neuronal survival, neurogenes, angiogenesis, excitatory and inhibitory neurotransmission, regulation of food intake, and cognition. In recent years, a linkage between brain insulin/IGF1 and certain neuropathologies has been identified. Epidemiological studies have demonstrated a correlation between diabetes (mainly type 2) and Alzheimer׳s disease. In addition, an aberrant decline in IGF1 values was suggested to play a role in the development of Alzheimer׳s disease. The present review focuses on the expression and function of insulin, IGFs and their receptors in the brain in physiological and pathological conditions. Copyright © 2014 Elsevier B.V. and ECNP. All rights reserved.

  6. Elevated toll-like receptor 4 expression and signaling in muscle from insulin-resistant subjects.

    Science.gov (United States)

    Reyna, Sara M; Ghosh, Sangeeta; Tantiwong, Puntip; Meka, C S Reddy; Eagan, Phyllis; Jenkinson, Christopher P; Cersosimo, Eugenio; Defronzo, Ralph A; Coletta, Dawn K; Sriwijitkamol, Apiradee; Musi, Nicolas

    2008-10-01

    OBJECTIVE- Tall-like receptor (TLR)4 has been implicated in the pathogenesis of free fatty acid (FFA)-induced insulin resistance by activating inflammatory pathways, including inhibitor of kappaB (IkappaB)/nuclear factor kappaB (NFkappaB). However, it is not known whether insulin-resistant subjects have abnormal TLR4 signaling. We examined whether insulin-resistant subjects have abnormal TLR4 expression and TLR4-driven (IkappaB/NFkappaB) signaling in skeletal muscle. RESEARCH DESIGN AND METHODS- TLR4 gene expression and protein content were measured in muscle biopsies in 7 lean, 8 obese, and 14 type 2 diabetic subjects. A primary human myotube culture system was used to examine whether FFAs stimulate IkappaB/NFkappaB via TLR4 and whether FFAs increase TLR4 expression/content in muscle. RESULTS- Obese and type 2 diabetic subjects had significantly elevated TLR4 gene expression and protein content in muscle. TLR4 muscle protein content correlated with the severity of insulin resistance. Obese and type 2 diabetic subjects also had lower IkappaBalpha content, an indication of elevated IkappaB/NFkappaB signaling. The increase in TLR4 and NFkappaB signaling was accompanied by elevated expression of the NFkappaB-regulated genes interleukin (IL)-6 and superoxide dismutase (SOD)2. In primary human myotubes, acute palmitate treatment stimulated IkappaB/NFkappaB, and blockade of TLR4 prevented the ability of palmitate to stimulate the IkappaB/NFkappaB pathway. Increased TLR4 content and gene expression observed in muscle from insulin-resistant subjects were reproduced by treating myotubes from lean, normal-glucose-tolerant subjects with palmitate. Palmitate also increased IL-6 and SOD2 gene expression, and this effect was prevented by inhibiting NFkappaB. CONCLUSIONS- Abnormal TLR4 expression and signaling, possibly caused by elevated plasma FFA levels, may contribute to the pathogenesis of insulin resistance in humans.

  7. Expression profiling analysis: Uncoupling protein 2 deficiency improves hepatic glucose, lipid profiles and insulin sensitivity in high-fat diet-fed mice by modulating expression of genes in peroxisome proliferator-activated receptor signaling pathway.

    Science.gov (United States)

    Zhou, Mei-Cen; Yu, Ping; Sun, Qi; Li, Yu-Xiu

    2016-03-01

    Uncoupling protein 2 (UCP2), which was an important mitochondrial inner membrane protein associated with glucose and lipid metabolism, widely expresses in all kinds of tissues including hepatocytes. The present study aimed to explore the impact of UCP2 deficiency on glucose and lipid metabolism, insulin sensitivity and its effect on the liver-associated signaling pathway by expression profiling analysis. Four-week-old male UCP2-/- mice and UCP2+/+ mice were randomly assigned to four groups: UCP2-/- on a high-fat diet, UCP2-/- on a normal chow diet, UCP2+/+ on a high-fat diet and UCP2+/+ on a normal chow diet. The differentially expressed genes in the four groups on the 16th week were identified by Affymetrix gene array. The results of intraperitoneal glucose tolerance test and insulin tolerance showed that blood glucose and β-cell function were improved in the UCP2-/- group on high-fat diet. Enhanced insulin sensitivity was observed in the UCP2-/- group. The differentially expressed genes were mapped to 23 pathways (P high-fat diet. The upregulation of genes in the PPAR signaling pathway could explain our finding that UCP2 deficiency ameliorated insulin sensitivity. The manipulation of UCP2 protein expression could represent a new strategy for the prevention and treatment of diabetes.

  8. Variants of Insulin-Signaling Inhibitor Genes in Type 2 Diabetes and Related Metabolic Abnormalities

    Directory of Open Access Journals (Sweden)

    Carlo de Lorenzo

    2013-01-01

    Full Text Available Insulin resistance has a central role in the pathogenesis of several metabolic diseases, including type 2 diabetes, obesity, glucose intolerance, metabolic syndrome, atherosclerosis, and cardiovascular diseases. Insulin resistance and related traits are likely to be caused by abnormalities in the genes encoding for proteins involved in the composite network of insulin-signaling; in this review we have focused our attention on genetic variants of insulin-signaling inhibitor molecules. These proteins interfere with different steps in insulin-signaling: ENPP1/PC-1 and the phosphatases PTP1B and PTPRF/LAR inhibit the insulin receptor activation; INPPL1/SHIP-2 hydrolyzes PI3-kinase products, hampering the phosphoinositide-mediated downstream signaling; and TRIB3 binds the serine-threonine kinase Akt, reducing its phosphorylation levels. While several variants have been described over the years for all these genes, solid evidence of an association with type 2 diabetes and related diseases seems to exist only for rs1044498 of the ENPP1 gene and for rs2295490 of the TRIB3 gene. However, overall the data recapitulated in this Review article may supply useful elements to interpret the results of novel, more technically advanced genetic studies; indeed it is becoming increasingly evident that genetic information on metabolic diseases should be interpreted taking into account the complex biological pathways underlying their pathogenesis.

  9. Reduced Insulin Receptor Expression Enhances Proximal Tubule Gluconeogenesis.

    Science.gov (United States)

    Pandey, Gaurav; Shankar, Kripa; Makhija, Ekta; Gaikwad, Anil; Ecelbarger, Carolyn; Mandhani, Anil; Srivastava, Aneesh; Tiwari, Swasti

    2017-02-01

    Reduced insulin receptor protein levels have been reported in the kidney cortex from diabetic humans and animals. We recently reported that, targeted deletion of insulin receptor (IR) from proximal tubules (PT) resulted in hyperglycemia in non-obese mice. To elucidate the mechanism, we examined human proximal tubule cells (hPTC) and C57BL/6 mice fed with high-fat diet (HFD, 60% fat for 20 weeks). Immunoblotting revealed a significantly lower protein level of IR in HFD compare to normal chow diet (NCD). Furthermore, a blunted rise in p-AKT 308 levels in the kidney cortex of HFD mice was observed in response to acute insulin (0.75 IU/kg body weight, i.p) relative to NCD n = 8/group, P gluconeogenesis. Transcript levels of the gluconeogenic enzyme PEPCK were significantly increased in cAMP/DEXA-stimulated hPTC cells (n = 3, P gluconeogenesis and PEPCK induction was significantly attenuated in IR (siRNA) silenced hPTC (n = 3, P gluconeogenesis. Thus reduced insulin signaling of the proximal tubule may contribute to hyperglycemia in the metabolic syndrome via elevated gluconeogenesis. J. Cell. Biochem. 118: 276-285, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  10. Structural analogs of human insulin-like growth factor I with reduced affinity for serum binding proteins and the type 2 insulin-like growth factor receptor

    International Nuclear Information System (INIS)

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

    1988-01-01

    Four structural analogs of human insulin-like growth factor I (hIGF-I) have been prepared by site-directed mutagenesis of a synthetic IGF-I gene and subsequent expression and purification of the mutant protein from the conditioned media of transformed yeast. [Phe -1 , Val 1 , Asn 2 , Gln 3 , His 4 , Ser 8 , His 9 , Glu 12 , Tyr 15 , Leu 16 ]IGF-I (B-chain mutant), in which the first 16 amino acids of hIGF-I were replaced with the first 17 amino acids of the B-chain of insulin, has >1000-, 100-, and 2-fold reduced potency for human serum binding proteins, the rat liver type 2 IGF receptor, and the human placental type 1 IGF receptor, respectively. The B-chain mutant also has 4-fold increased affinity for the human placental insulin receptor. [Gln 3 , Ala 4 ] IGF-I has 4-fold reduced affinity for human serum binding proteins, but is equipotent to hIGF-I at the types 1 and 2 IGF and insulin receptors. [Tyr 15 , Leu 16 ] IGH-I has 4-fold reduced affinity for human serum binding proteins and 10-fold increased affinity for the insulin receptor. The peptide in which these four-point mutations are combined, [Gln 3 , Ala 4 , Tyr 15 ,Leu 16 ]IGF-I, has 600-fold reduced affinity for the serum binding proteins. All four of these mutants stimulate DNA synthesis in the rat vascular smooth muscle cell line A10 with potencies reflecting their potency at the type 1 IGF receptor. These studies identify some of the domains of hIGF-I which are responsible for maintaining high affinity binding with the serum binding protein and the type 2 IGF receptor. In addition, These peptides will be useful in defining the role of the type 2 IGF receptor and serum binding proteins in the physiological actions of hIGF-I

  11. Insulin receptor binding and protein kinase activity in muscles of trained rats

    International Nuclear Information System (INIS)

    Dohm, G.L.; Sinha, M.K.; Caro, J.F.

    1987-01-01

    Exercise has been shown to increase insulin sensitivity, and muscle is quantitatively the most important tissue of insulin action. Since the first step in insulin action is the binding to a membrane receptor, the authors postulated that exercise training would change insulin receptors in muscle and in this study they have investigated this hypothesis. Female rats initially weighing ∼ 100 g were trained by treadmill running for 2 h/day, 6 days/wk for 4 wk at 25 m/min (0 grade). Insulin receptors from vastus intermedius muscles were solubilized by homogenizing in a buffer containing 1% Triton X-100 and then partially purified by passing the soluble extract over a wheat germ agglutinin column. The 4 wk training regimen resulted in a 65% increase in citrate synthase activity in red vastus lateralis muscle, indicating an adaptation to exercise [ 125 I]. Insulin binding by the partially purified receptor preparations was approximately doubled in muscle of trained rats at all insulin concentrations, suggesting an increase in the number of receptors. Training did not alter insulin receptor structure as evidenced by electrophoretic mobility under reducing and nonreducing conditions. Basal insulin receptor protein kinase activity was higher in trained than untrained animals and this was likely due to the greater number of receptors. However, insulin stimulation of the protein kinase activity was depressed by training. These results demonstrate that endurance training does alter receptor number and function in muscle and these changes may be important in increasing insulin sensitivity after exercise training

  12. A BRET assay for monitoring insulin receptor interactions and ligand pharmacology

    DEFF Research Database (Denmark)

    Kulahin, Nikolaj; Sanni, Samra J; Slaaby, Rita

    2012-01-01

    The insulin receptor (IR) belongs to the receptor tyrosine kinase super family and plays an important role in glucose homeostasis. The receptor interacts with several large docking proteins that mediate signaling from the receptor, including the insulin receptor substrate (IRS) family and Src...... for monitoring the interactions between the IR and its substrates. Furthermore, the insulin analogue X10 was characterized in the BRET2 assay and was found to be 10 times more potent with respect to IRS1, IRS4 and Shc recruitment compared to human insulin. This study demonstrates that the BRET2 technique can...

  13. New twist on neuronal insulin receptor signaling in health, disease, and therapeutics.

    Science.gov (United States)

    Wada, Akihiko; Yokoo, Hiroki; Yanagita, Toshihiko; Kobayashi, Hideyuki

    2005-10-01

    Long after the pioneering studies documenting the existence of insulin (year 1967) and insulin receptor (year 1978) in brain, the last decade has witnessed extraordinary progress in the understanding of brain region-specific multiple roles of insulin receptor signalings in health and disease. In the hypothalamus, insulin regulates food intake, body weight, peripheral fat deposition, hepatic gluconeogenesis, reproductive endocrine axis, and compensatory secretion of counter-regulatory hormones to hypoglycemia. In the hippocampus, insulin promotes learning and memory, independent of the glucoregulatory effect of insulin. Defective insulin receptor signalings are associated with the dementia in normal aging and patients with age-related neurodegenerative diseases (e.g., Alzheimer's disease); the cognitive impairment can be reversed with systemic administration of insulin in the euglycemic condition. Intranasal administration of insulin enhances memory and mood and decreases body weight in healthy humans, without causing hypoglycemia. In the hypothalamus, insulin-induced activation of the phosphoinositide 3-kinase pathway followed by opening of ATP-sensitive K+ channel has been shown to be related to multiple effects of insulin. However, the precise molecular mechanisms of insulin's pleiotropic effects still remain obscure. More importantly, much remains unknown about the quality control mechanisms ensuring correct conformational maturation of the insulin receptor, and the cellular mechanisms regulating density of cell surface functional insulin receptors.

  14. Association of the insulin-receptor variant Met-985 with hyperglycemia and non-insulin-dependent diabetes mellitus in the Netherlands : A population-based study

    NARCIS (Netherlands)

    tHart, LM; Stolk, RP; Heine, RJ; Grobbee, DE; vanderDoes, FEE; Maassen, JA

    1996-01-01

    One of the characteristics of non-insulin-dependent diabetes mellitus (NIDDM) is the presence of insulin resistance. Most NIDDM patients have a normal sequence of the insulin receptor, indicating that, if insulin-receptor mutations contribute to the development of NIDDM, they will be present only in

  15. Association of the insulin-receptor variant Met-985 with hyperglycemia and non-insulin-dependent diabetes mellitus in the Netherlands : A population-based study

    NARCIS (Netherlands)

    tHart, LM; Stolk, RP; Heine, RJ; Grobbee, DE; vanderDoes, FEE; Maassen, JA

    One of the characteristics of non-insulin-dependent diabetes mellitus (NIDDM) is the presence of insulin resistance. Most NIDDM patients have a normal sequence of the insulin receptor, indicating that, if insulin-receptor mutations contribute to the development of NIDDM, they will be present only in

  16. Differential roles of SS18-SSX fusion gene and insulin-like growth factor-1 receptor in synovial sarcoma cell growth

    International Nuclear Information System (INIS)

    Toernkvist, Maria; Natalishvili, Natalia; Xie Yuntao; Girnita, Ada; D'Arcy, Padraig; Brodin, Bertha; Axelson, Magnus; Girnita, Leonard

    2008-01-01

    Recently we demonstrated that the synovial sarcoma specific fusion gene SS18-SSX is crucial for cyclin D1 expression and is linked to cell proliferation. In this report we explore the role of SS18-SSX and IGF-1R for their potential functions in cellular proliferation and survival in cultured synovial sarcoma cells. We found that targeting of SS18-SSX mRNA by antisense oligonucleotide treatment drastically and rapidly decreased cell proliferation but caused only a slight increase of apoptosis. The synovial sarcoma cells were confirmed to express IGF-1R, and treatment with an IGF-1R inhibitor resulted in substantially reduced cell viability by inducing apoptosis in these cells. Conversely, inhibition of the IGF-1R resulted only in a slight to moderate decrease in DNA synthesis. In conclusion, SS18-SSX and IGF-1R seem to play important but different roles in maintaining malignant growth of synovial sarcoma cells. Whereas SS18-SSX maintains cyclin D1 and cell proliferation, IGF-1R protects from apoptosis

  17. Role of the Insulin-Like Growth Factor Type 1 Receptor in the Pathogenesis of Diabetic Encephalopathy

    Directory of Open Access Journals (Sweden)

    Duo Zhang

    2015-01-01

    Full Text Available Defective cognitive function is common in patients with diabetes, suggesting that insulin normally exerts anabolic actions in neuron, namely, diabetic encephalopathy. However, because insulin can cross-activate the insulin-like growth factor type 1 receptor (IGF-1R, which also functions in most of tissues, such as muscle and bone, it has been difficult to establish the direct (IGF-1-independent actions of insulin in the pathogenesis of diabetic encephalopathy. To overcome this problem, we examined insulin signaling and action in primary PC-12 cells engineered for conditional disruption of the IGF-1 receptor (ΔIGF-1R. The results showed that the lower glucose metabolism and high expression of IGF-1R occurred in the brain of the DE rat model. The results also showed the defect of IGF-1R could significantly improve the ability of glucose consumption and enhance sensitivity to insulin-induced IR and Akt phosphorylation in PC12 cells. And meanwhile, IGF-1R allele gene knockout (IGF-1Rneo mice treated with HFD/STZ had better cognitive abilities than those of wild mice. Those results indicate that insulin exerts direct anabolic actions in neuron-like cells by activation of its cognate receptor and prove that IGF-1R plays an important role in the pathogenesis of diabetic encephalopathy.

  18. APPL1 potentiates insulin sensitivity by facilitating the binding of IRS1/2 to the insulin receptor.

    Science.gov (United States)

    Ryu, Jiyoon; Galan, Amanda K; Xin, Xiaoban; Dong, Feng; Abdul-Ghani, Muhammad A; Zhou, Lijun; Wang, Changhua; Li, Cuiling; Holmes, Bekke M; Sloane, Lauren B; Austad, Steven N; Guo, Shaodong; Musi, Nicolas; DeFronzo, Ralph A; Deng, Chuxia; White, Morris F; Liu, Feng; Dong, Lily Q

    2014-05-22

    Binding of insulin receptor substrate proteins 1 and 2 (IRS1/2) to the insulin receptor (IR) is essential for the regulation of insulin sensitivity and energy homeostasis. However, the mechanism of IRS1/2 recruitment to the IR remains elusive. Here, we identify adaptor protein APPL1 as a critical molecule that promotes IRS1/2-IR interaction. APPL1 forms a complex with IRS1/2 under basal conditions, and this complex is then recruited to the IR in response to insulin or adiponectin stimulation. The interaction between APPL1 and IR depends on insulin- or adiponectin-stimulated APPL1 phosphorylation, which is greatly reduced in insulin target tissues in obese mice. appl1 deletion in mice consistently leads to systemic insulin resistance and a significant reduction in insulin-stimulated IRS1/2, but not IR, tyrosine phosphorylation, indicating that APPL1 sensitizes insulin signaling by acting at a site downstream of the IR. Our study uncovers a mechanism regulating insulin signaling and crosstalk between the insulin and adiponectin pathways. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

  19. Evidence that phosphatidylcholine-specific phospholipase C is a key molecule mediating insulin-induced enhancement of gene expression from human cytomegalovirus promoter in CHO cells

    OpenAIRE

    Zhang, Yingpei; Katakura, Yoshinori; Seto, Perry; Shirahata, Sanetaka

    1997-01-01

    The signal transduction from insulin to its receptors and Ras has been extensively studied, while little has been reported beyond these steps. We found that the expression of human interleukin 6 gene under the control of immediate early gene promoter of human cytomegalovirus was enhanced by insulin sitmulation in Chinese hamster ovary cells. The induction effect of insulin was not significantly affected by inhibitors or activators of conventional protein kinase C, cAMP dependent protein kinas...

  20. S961, an insulin receptor antagonist causes hyperinsulinemia, insulin-resistance and depletion of energy stores in rats

    Energy Technology Data Exchange (ETDEWEB)

    Vikram, Ajit [Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), SAS Nagar, Mohali, Punjab 160 062 (India); Jena, Gopabandhu, E-mail: gbjena@gmail.com [Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), SAS Nagar, Mohali, Punjab 160 062 (India)

    2010-07-23

    Research highlights: {yields}Insulin receptor antagonist S961 causes hyperglycemia, hyperinsulinemia and insulin resistance in rats. {yields}Peroxysome-proliferator-activated-receptor-gamma agonist pioglitazone improves S961 induced hyperglycemia and glucose intolerance. {yields}Long term treatment with insulin receptor antagonist S961 results in the decreased adiposity and hepatic glycogen content. {yields}Improvement in the hyperglycemia and glucose intolerance by pioglitazone clearly demonstrates that S961 treated rats can be successfully used to screen the novel therapeutic interventions having potential to improve glucose disposal through receptor independent mechanisms. -- Abstract: Impairment in the insulin receptor signaling and insulin mediated effects are the key features of type 2 diabetes. Here we report that S961, a peptide insulin receptor antagonist induces hyperglycemia, hyperinsulinemia ({approx}18-fold), glucose intolerance and impairment in the insulin mediated glucose disposal in the Sprague-Dawley rats. Further, long-term S961 treatment (15 day, 10 nM/kg/day) depletes energy storage as evident from decrease in the adiposity and hepatic glycogen content. However, peroxysome-proliferator-activated-receptor-gamma (PPAR{gamma}) agonist pioglitazone significantly (P < 0.001) restored S961 induced hyperglycemia (196.73 {+-} 16.32 vs. 126.37 {+-} 27.07 mg/dl) and glucose intolerance ({approx}78%). Improvement in the hyperglycemia and glucose intolerance by pioglitazone clearly demonstrates that S961 treated rats can be successfully used to screen the novel therapeutic interventions having potential to improve glucose disposal through receptor independent mechanisms. Further, results of the present study reconfirms and provide direct evidence to the crucial role of insulin receptor signaling in the glucose homeostasis and fuel metabolism.

  1. S961, an insulin receptor antagonist causes hyperinsulinemia, insulin-resistance and depletion of energy stores in rats

    International Nuclear Information System (INIS)

    Vikram, Ajit; Jena, Gopabandhu

    2010-01-01

    Research highlights: →Insulin receptor antagonist S961 causes hyperglycemia, hyperinsulinemia and insulin resistance in rats. →Peroxysome-proliferator-activated-receptor-gamma agonist pioglitazone improves S961 induced hyperglycemia and glucose intolerance. →Long term treatment with insulin receptor antagonist S961 results in the decreased adiposity and hepatic glycogen content. →Improvement in the hyperglycemia and glucose intolerance by pioglitazone clearly demonstrates that S961 treated rats can be successfully used to screen the novel therapeutic interventions having potential to improve glucose disposal through receptor independent mechanisms. -- Abstract: Impairment in the insulin receptor signaling and insulin mediated effects are the key features of type 2 diabetes. Here we report that S961, a peptide insulin receptor antagonist induces hyperglycemia, hyperinsulinemia (∼18-fold), glucose intolerance and impairment in the insulin mediated glucose disposal in the Sprague-Dawley rats. Further, long-term S961 treatment (15 day, 10 nM/kg/day) depletes energy storage as evident from decrease in the adiposity and hepatic glycogen content. However, peroxysome-proliferator-activated-receptor-gamma (PPARγ) agonist pioglitazone significantly (P < 0.001) restored S961 induced hyperglycemia (196.73 ± 16.32 vs. 126.37 ± 27.07 mg/dl) and glucose intolerance (∼78%). Improvement in the hyperglycemia and glucose intolerance by pioglitazone clearly demonstrates that S961 treated rats can be successfully used to screen the novel therapeutic interventions having potential to improve glucose disposal through receptor independent mechanisms. Further, results of the present study reconfirms and provide direct evidence to the crucial role of insulin receptor signaling in the glucose homeostasis and fuel metabolism.

  2. A novel insulin receptor-binding protein from Momordica charantia enhances glucose uptake and glucose clearance in vitro and in vivo through triggering insulin receptor signaling pathway.

    Science.gov (United States)

    Lo, Hsin-Yi; Ho, Tin-Yun; Li, Chia-Cheng; Chen, Jaw-Chyun; Liu, Jau-Jin; Hsiang, Chien-Yun

    2014-09-10

    Diabetes, a common metabolic disorder, is characterized by hyperglycemia. Insulin is the principal mediator of glucose homeostasis. In a previous study, we identified a trypsin inhibitor, named Momordica charantia insulin receptor (IR)-binding protein (mcIRBP) in this study, that might interact with IR. The physical and functional interactions between mcIRBP and IR were clearly analyzed in the present study. Photo-cross-linking coupled with mass spectrometry showed that three regions (17-21, 34-40, and 59-66 residues) located on mcIRBP physically interacted with leucine-rich repeat domain and cysteine-rich region of IR. IR-binding assay showed that the binding behavior of mcIRBP and insulin displayed a cooperative manner. After binding to IR, mcIRBP activated the kinase activity of IR by (5.87 ± 0.45)-fold, increased the amount of phospho-IR protein by (1.31 ± 0.03)-fold, affected phosphoinositide-3-kinase/Akt pathways, and consequently stimulated the uptake of glucose in 3T3-L1 cells by (1.36 ± 0.12)-fold. Intraperitoneal injection of 2.5 nmol/kg mcIRBP significantly decreased the blood glucose levels by 20.9 ± 3.2% and 10.8 ± 3.6% in normal and diabetic mice, respectively. Microarray analysis showed that mcIRBP affected genes involved in insulin signaling transduction pathway in mice. In conclusion, our findings suggest that mcIRBP is a novel IRBP that binds to sites different from the insulin-binding sites on IR and stimulates both the glucose uptake in cells and the glucose clearance in mice.

  3. Dual pathways for the intracellular processing of insulin. Relationship between retroendocytosis of intact hormone and the recycling of insulin receptors

    International Nuclear Information System (INIS)

    Marshall, S.

    1985-01-01

    Adipocytes process insulin through either of two pathways: a retroendocytotic pathway that culminates in the release of intact insulin, and a degradative pathway that terminates in the intracellular catabolism and release of degraded ligand. Mechanistically, these pathways were found to differ in several ways. First, temporal differences were found in the rate at which intact and degraded products were extruded. After 125 I-insulin was preloaded into the cell interior, intact ligand was completely released during the first 10 min (t 1/2 = 2 min), whereas degraded insulin was released at a much slower rate over 1 h (t 1/2 greater than 8 min). Secondly, it was found that chloroquine profoundly inhibited the insulin degradative pathway, resulting in the intracellular accumulation of intact ligand and a reduction in the release of degraded products. In contrast, however, chloroquine was without effect on the retroendocytotic processing of insulin. Based on the known actions of chloroquine, it appears that retroendocytosis of insulin does not involve vesicular acidification or dissociation of the insulin-receptor complex and that insulin is most likely carried to the cell exterior in the same vesicles (either receptor-bound or free) as those mediating recycling receptors. Interestingly, accumulation of undergraded insulin within chloroquine-treated cells did not result in the release of additional intact ligand, suggesting that once insulin enters the degradative compartment it is committed to catabolism and cannot exit the cell through the retroendocytotic pathway. A third difference was revealed by the finding that extracellular unlabeled insulin (100 ng/ml) markedly accelerated the rate at which preloaded 125 I-insulin was released from adipocytes (t 1/2 of 3 min versus 7 min in controls cells)

  4. 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...

  5. Relation between the insulin receptor number in cells, autophosphorylation and insulin-stimulated Ras.GTP formation

    NARCIS (Netherlands)

    Osterop, A.P.R.M.; Medema, R.H.; Bos, J.L.; Zon, G.C.M. van der; Moller, D.E.; Flier, J.S.; Möller, W.; Maassen, J.A.

    1992-01-01

    We showed previously that upon insulin stimulation of an insulin receptor overexpressing cell linme,o st of the p2lras warsa pidly converted into the GTP bound state (Burgering, B. M. T., Medema, R. H., Maassen, J. A., Van de Wetering, M. L., Van der Eb, A. J., McCormick, F., and Bos, J. L.

  6. Endothelial Fcγ Receptor IIB Activation Blunts Insulin Delivery to Skeletal Muscle to Cause Insulin Resistance in Mice

    Science.gov (United States)

    Tanigaki, Keiji; Chambliss, Ken L.; Yuhanna, Ivan S.; Sacharidou, Anastasia; Ahmed, Mohamed; Atochin, Dmitriy N.; Huang, Paul L.

    2016-01-01

    Modest elevations in C-reactive protein (CRP) are associated with type 2 diabetes. We previously revealed in mice that increased CRP causes insulin resistance and mice globally deficient in the CRP receptor Fcγ receptor IIB (FcγRIIB) were protected from the disorder. FcγRIIB is expressed in numerous cell types including endothelium and B lymphocytes. Here we investigated how endothelial FcγRIIB influences glucose homeostasis, using mice with elevated CRP expressing or lacking endothelial FcγRIIB. Whereas increased CRP caused insulin resistance in mice expressing endothelial FcγRIIB, mice deficient in the endothelial receptor were protected. The insulin resistance with endothelial FcγRIIB activation was due to impaired skeletal muscle glucose uptake caused by attenuated insulin delivery, and it was associated with blunted endothelial nitric oxide synthase (eNOS) activation in skeletal muscle. In culture, CRP suppressed endothelial cell insulin transcytosis via FcγRIIB activation and eNOS antagonism. Furthermore, in knock-in mice harboring constitutively active eNOS, elevated CRP did not invoke insulin resistance. Collectively these findings reveal that by inhibiting eNOS, endothelial FcγRIIB activation by CRP blunts insulin delivery to skeletal muscle to cause insulin resistance. Thus, a series of mechanisms in endothelium that impairs insulin movement has been identified that may contribute to type 2 diabetes pathogenesis. PMID:27207525

  7. Insulin gene therapy for type 1 diabetes mellitus.

    Science.gov (United States)

    Handorf, Andrew M; Sollinger, Hans W; Alam, Tausif

    2015-04-01

    Type 1 diabetes mellitus is an autoimmune disease resulting from the destruction of pancreatic β cells. Current treatments for patients with type 1 diabetes mellitus include daily insulin injections or whole pancreas transplant, each of which are associated with profound drawbacks. Insulin gene therapy, which has shown great efficacy in correcting hyperglycemia in animal models, holds great promise as an alternative strategy to treat type 1 diabetes mellitus in humans. Insulin gene therapy refers to the targeted expression of insulin in non-β cells, with hepatocytes emerging as the primary therapeutic target. In this review, we present an overview of the current state of insulin gene therapy to treat type 1 diabetes mellitus, including the need for an alternative therapy, important features dictating the success of the therapy, and current obstacles preventing the translation of this treatment option to a clinical setting. In so doing, we hope to shed light on insulin gene therapy as a viable option to treat type 1 diabetes mellitus.

  8. [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.

  9. Comparison of solubilized and purified plasma membrane and nuclear insulin receptors

    International Nuclear Information System (INIS)

    Wong, K.Y.; Hawley, D.; Vigneri, R.; Goldfine, I.D.

    1988-01-01

    Prior studies have detected biochemical and immunological differences between insulin receptors in plasma membranes and isolated nuclei. To further investigate these receptors, they were solubilized in Triton X-100 partially purified by wheat germ agglutinin-agarose chromatography. In these preparations, the nuclear and plasma membrane receptors had very similar pH optima (pH 8.0) and reactivities to a group of polyclonal antireceptor antibodies. Further, both membrane preparations had identical binding activities when labeled insulin was competed for by unlabeled insulin (50% inhibition at 800 pM). Next, nuclear and plasma membranes were solubilized and purified to homogeneity by wheat germ agglutinin-agarose and insulin-agarose chromatography. In both receptors, labeled insulin was covalently cross-linked to a protein of 130 kilodaltons representing the insulin receptor α subunit. When preparations of both receptors were incubated with insulin and then adenosine 5'-[γ- 32 P]triphosphate, a protein of 95 kilodaltons representing the insulin receptor β subunit was phosphorylated in a dose-dependent manner. These studies indicate, therefore, that solubilized plasma membrane and nuclear insulin receptors have similar structures and biochemical properties, and they suggest that they are the same (or very similar) proteins

  10. Inter-domain tagging implicates caveolin-1 in insulin receptor trafficking and Erk signaling bias in pancreatic beta-cells

    Directory of Open Access Journals (Sweden)

    Tobias Boothe

    2016-05-01

    Full Text Available Objective: The role and mechanisms of insulin receptor internalization remain incompletely understood. Previous trafficking studies of insulin receptors involved fluorescent protein tagging at their termini, manipulations that may be expected to result in dysfunctional receptors. Our objective was to determine the trafficking route and molecular mechanisms of functional tagged insulin receptors and endogenous insulin receptors in pancreatic beta-cells. Methods: We generated functional insulin receptors tagged with pH-resistant fluorescent proteins between domains. Confocal, TIRF and STED imaging revealed a trafficking pattern of inter-domain tagged insulin receptors and endogenous insulin receptors detected with antibodies. Results: Surprisingly, interdomain-tagged and endogenous insulin receptors in beta-cells bypassed classical Rab5a- or Rab7-mediated endocytic routes. Instead, we found that removal of insulin receptors from the plasma membrane involved tyrosine-phosphorylated caveolin-1, prior to trafficking within flotillin-1-positive structures to lysosomes. Multiple methods of inhibiting caveolin-1 significantly reduced Erk activation in vitro or in vivo, while leaving Akt signaling mostly intact. Conclusions: We conclude that phosphorylated caveolin-1 plays a role in insulin receptor internalization towards lysosomes through flotillin-1-positive structures and that caveolin-1 helps bias physiological beta-cell insulin signaling towards Erk activation. Author Video: Author Video Watch what authors say about their articles Keywords: Insulin receptor internalization, Insulin resistance, Pancreatic islet beta-cells, Autocrine insulin signaling

  11. Anti hyperglycaemic study of natural inhibitors for Insulin receptor.

    Science.gov (United States)

    Chatterjee, Subhojyoti; Narasimhaiah, Akshaya Lakshmi; Kundu, Sanjay; Anand, Santosh

    2012-01-01

    Diabetes is a metabolic disorder associated with either improper functioning of the beta-cells or wherein cells fail to use insulin properly. Insulin, the principal hormone regulates uptake of glucose from the blood into most of the cells except central nervous system. Therefore, deficiency of insulin or the insensitivity of its receptors plays a key role in all forms of diabetes. In the present work, attempt has been made to find out plant sources which show anti hyperglycaemic activity (AhG) (i.e. compounds that bring down the blood glucose level in the body). Ayurvedic plants showing AhG activity formed the basis of our study by using the platform of Computer Aided Drug Designing (CADD). Among 600 plants showing AhG activity, 500 compounds were selected and screened, out of which 243 compounds showed drug likeness property that can be used as therapeutic ligand/drug. Initial screening of such compounds was done based on their drug likeness or biochemical properties. Dynamic interaction of these molecules was captured through Protein-Ligand study. It also gave an insight of the binding pockets involved. Bench marking of all the parameters were done using the diabetic inhibitor drug, Glipizide. Pharmacokinetic studies of the compounds such as Aloins, Capparisine, Funiculosin and Rhein exhibited less toxicity on various levels of the body. As a conclusion these ligands can lay a foundation for a better anti-diabetic therapy. AhG - Anti hyperglycaemic, CADD - Computer Aided Drug Designing.

  12. Ubiquitinated CD36 sustains insulin-stimulated Akt activation by stabilizing insulin receptor substrate 1 in myotubes.

    Science.gov (United States)

    Sun, Shishuo; Tan, Pengcheng; Huang, Xiaoheng; Zhang, Wei; Kong, Chen; Ren, Fangfang; Su, Xiong

    2018-02-16

    Both the magnitude and duration of insulin signaling are important in executing its cellular functions. Insulin-induced degradation of insulin receptor substrate 1 (IRS1) represents a key negative feedback loop that restricts insulin signaling. Moreover, high concentrations of fatty acids (FAs) and glucose involved in the etiology of obesity-associated insulin resistance also contribute to the regulation of IRS1 degradation. The scavenger receptor CD36 binds many lipid ligands, and its contribution to insulin resistance has been extensively studied, but the exact regulation of insulin sensitivity by CD36 is highly controversial. Herein, we found that CD36 knockdown in C2C12 myotubes accelerated insulin-stimulated Akt activation, but the activated signaling was sustained for a much shorter period of time as compared with WT cells, leading to exacerbated insulin-induced insulin resistance. This was likely due to enhanced insulin-induced IRS1 degradation after CD36 knockdown. Overexpression of WT CD36, but not a ubiquitination-defective CD36 mutant, delayed IRS1 degradation. We also found that CD36 functioned through ubiquitination-dependent binding to IRS1 and inhibiting its interaction with cullin 7, a key component of the multisubunit cullin-RING E3 ubiquitin ligase complex. Moreover, dissociation of the Src family kinase Fyn from CD36 by free FAs or Fyn knockdown/inhibition accelerated insulin-induced IRS1 degradation, likely due to disrupted IRS1 interaction with CD36 and thus enhanced binding to cullin 7. In summary, we identified a CD36-dependent FA-sensing pathway that plays an important role in negative feedback regulation of insulin activation and may open up strategies for preventing or managing type 2 diabetes mellitus. © 2018 by The American Society for Biochemistry and Molecular Biology, Inc.

  13. Characterization of the growth of murine fibroblasts that express human insulin receptors. II. Interaction of insulin with other growth factors

    International Nuclear Information System (INIS)

    Randazzo, P.A.; Jarett, L.

    1990-01-01

    The effects of insulin-like growth factor-1 (IGF-1), epidermal growth factor (EGF), platelet-derived growth factor (PDGF), and insulin on DNA synthesis were studied in murine fibroblasts transfected with an expression vector containing human insulin receptor cDNA (NIH 3T3/HIR) and the parental NIH 3T3 cells. In NIH 3T3/HIR cells, individual growth factors in serum-free medium stimulated DNA synthesis with the following relative efficacies: insulin greater than or equal to 10% fetal calf serum greater than PDGF greater than IGF-1 much greater than EGF. In comparison, the relative efficacies of these factors in stimulating DNA synthesis by NIH 3T3 cells were 10% fetal calf serum greater than PDGF greater than EGF much greater than IGF-1 = insulin. In NIH 3T3/HIR cells, EGF was synergistic with 1-10 ng/ml insulin but not with 100 ng/ml insulin or more. Synergy of PDGF or IGF-1 with insulin was not detected. In the parental NIH 3T3 cells, insulin and IGF-1 were found to be synergistic with EGF (1 ng/ml), PDGF (100 ng/ml), and PDGF plus EGF. In NIH 3T3/HIR cells, the lack of interaction of insulin with other growth factors was also observed when the percentage of cells synthesizing DNA was examined. Despite insulin's inducing only 60% of NIH 3T3/HIR cells to incorporate thymidine, addition of PDGF, EGF, or PDGF plus EGF had no further effect. In contrast, combinations of growth factors resulted in 95% of the parental NIH 3T3 cells synthesizing DNA. The independence of insulin-stimulated DNA synthesis from other mitogens in the NIH 3T3/HIR cells is atypical for progression factor-stimulated DNA synthesis and is thought to be partly the result of insulin receptor expression in an inappropriate context or quantity

  14. Hyperinsulinemia is associated with increased soluble insulin receptors release from hepatocytes

    Directory of Open Access Journals (Sweden)

    Marcia eHiriart

    2014-06-01

    Full Text Available It has been generally assumed that insulin circulates freely in blood. However it can also interact with plasma proteins. Insulin receptors are located in the membrane of target cells and consist of an alpha and beta subunits with a tyrosine kinase cytoplasmic domain. The ectodomain, called soluble insulin receptor (SIR has been found elevated in patients with diabetes mellitus. We explored if insulin binds to SIRs in circulation under physiological conditions and hypothesize that this SIR may be released by hepatocytes in response to high insulin concentrations. The presence of SIR in rat and human plasmas and the culture medium of hepatocytes was explored using Western blot analysis. A purification protocol was performed to isolated SIR using affinity, gel filtration and ion exchange chromatographies. A modified reverse hemolytic plaque assay was used to measure SIR release from cultured hepatocytes. Incubation with 1 nmol l-1 insulin induces the release of the insulin receptor ectodomains from normal rat hepatocytes. This effect can be partially prevented by blocking protease activity. Furthermore, plasma levels of SIR were higher in a model of metabolic syndrome, where rats are hyperinsulinemic. We also found increased SIR levels in hyperinsulinemic humans. SIR may be an important regulator of the amount of free insulin in circulation. In hyperinsulinemia the amount of this soluble receptor increases, this could lead to higher amounts of insulin bound to this receptor, rather than free insulin, which is the biologically active form of the hormone. This observation could enlighten the mechanisms of insulin resistance.

  15. Increased abundance of insulin/insulin-like growth factor-I hybrid receptors in skeletal muscle of obese subjects is correlated with in vivo insulin sensitivity.

    Science.gov (United States)

    Federici, M; Porzio, O; Lauro, D; Borboni, P; Giovannone, B; Zucaro, L; Hribal, M L; Sesti, G

    1998-08-01

    We reported that in noninsulin-dependent diabetes melitus (NIDDM) patients expression of insulin/insulin-like growth factor I (IGF-I) hybrid receptors is increased in insulin target tissues. Whether this is a defect associated with NIDDM or represents a generalized abnormality associated with insulin resistant states is still unsettled. To address this, we applied a microwell-based immunoassay to measure abundance of insulin receptors, type 1 IGF receptors, and hybrid receptors in muscle of eight normal and eight obese subjects. Maximal insulin binding to insulin receptors was lower in obese than in control subjects (B/T = 1.8 +/- 0.20 and 2.6 +/- 0.30; P < 0.03, respectively) and was negatively correlated with insulinemia (r = -0.60; P < 0.01). Maximal IGF-I binding to type 1 IGF receptors was higher in obese than in controls (B/T = 1.9 +/- 0.20 and 0.86 +/- 0.10; P < 0.0001, respectively) and was negatively correlated with plasma IGF-I levels (r = -0.69; P < 0.003). Hybrid receptor abundance was higher in obese than in normal subjects (B/T = 1.21 +/- 0.14 and 0.44 +/- 0.06; P < 0.0003, respectively) and was negatively correlated with insulin binding (r = -0.60; P < 0.01) and positively correlated with IGF-I binding (r = 0.92; P < 0.0001). Increased abundance of hybrids was correlated with insulinemia (r = 0.70; P < 0.002) and body mass index (r = 0.71; P < 0.0019), whereas it was negatively correlated with in vivo insulin sensitivity measured by ITT (r = -0.67; P < 0.016). These results indicate that downregulation of insulin receptors or upregulation of type 1 IGF receptors because of changes in plasma insulin and IGF-I levels may result in modifications in hybrid receptor abundance.

  16. Glycogen Synthase Kinase-3 regulates IGFBP-1 gene transcription through the Thymine-rich Insulin Response Element

    Directory of Open Access Journals (Sweden)

    Marquez Rodolfo

    2004-09-01

    Full Text Available Abstract Background Hepatic expression of several gene products involved in glucose metabolism, including phosphoenolpyruvate carboxykinase (PEPCK, glucose-6-phosphatase (G6Pase and insulin-like growth factor binding protein-1 (IGFBP-1, is rapidly and completely inhibited by insulin. This inhibition is mediated through the regulation of a DNA element present in each of these gene promoters, that we call the Thymine-rich Insulin Response Element (TIRE. The insulin signalling pathway that results in the inhibition of these gene promoters requires the activation of phosphatidylinositol 3-kinase (PI 3-kinase. However, the molecules that connect PI 3-kinase to these gene promoters are not yet fully defined. Glycogen Synthase Kinase 3 (GSK-3 is inhibited following activation of PI 3-kinase. We have shown previously that inhibitors of GSK-3 reduce the activity of two TIRE-containing gene promoters (PEPCK and G6Pase, whose products are required for gluconeogenesis. Results In this report we demonstrate that in H4IIE-C3 cells, four distinct classes of GSK-3 inhibitor mimic the effect of insulin on a third TIRE-containing gene, IGFBP-1. We identify the TIRE as the minimum requirement for inhibition by these agents, and demonstrate that the target of GSK-3 is unlikely to be the postulated TIRE-binding protein FOXO-1. Importantly, overexpression of GSK-3 in cells reduces the insulin regulation of TIRE activity as well as endogenous IGFBP-1 expression. Conclusions These results implicate GSK-3 as an intermediate in the pathway from the insulin receptor to the TIRE. Indeed, this is the first demonstration of an absolute requirement for GSK-3 inhibition in insulin regulation of gene transcription. These data support the potential use of GSK-3 inhibitors in the treatment of insulin resistant states such as Type 2 diabetes mellitus, but suggest that it will be important to identify all TIRE-containing genes to assess potential side effects of these agents.

  17. Increased interaction with insulin receptor substrate 1, a novel abnormality in insulin resistance and type 2 diabetes

    DEFF Research Database (Denmark)

    Caruso, Michael; Ma, Danjun; Msallaty, Zaher

    2014-01-01

    Insulin receptor substrate 1 (IRS1) is a key mediator of insulin signal transduction. Perturbations involving IRS1 complexes may lead to the development of insulin resistance and type 2 diabetes (T2D). Surprisingly little is known about the proteins that interact with IRS1 in humans under health...... in obesity and T2D in humans, provides new insights into the molecular mechanism of insulin resistance and identifies new targets for T2D drug development....... and disease conditions. We used a proteomic approach to assess IRS1 interaction partners in skeletal muscle from lean healthy control subjects (LCs), obese insulin-resistant nondiabetic control subjects (OCs), and participants with T2D before and after insulin infusion. We identified 113 novel endogenous IRS1...

  18. Comparative effects of several simple carbohydrates on erythrocyte insulin receptors in obese subjects.

    Science.gov (United States)

    Rizkalla, S W; Baigts, F; Fumeron, F; Rabillon, B; Bayn, P; Ktorza, A; Spielmann, D; Apfelbaum, M

    1986-09-01

    The effects of simple carbohydrates on erythrocyte insulin receptors, plasma insulin and plasma glucose were studied during four hypocaloric, hyperproteic, diets. One diet contained no carbohydrate; the other three contained 36 g of either glucose, galactose or fructose. These diets were given for a 14-day period to groups of moderately obese subjects. The hypocaloric carbohydrate-free diet produced a decrease in plasma insulin and glucose concentrations concomitant with an increase in the number of insulin receptors. A similar increase in insulin receptor number was found when the diet was supplemented with glucose or galactose, but not with fructose. The presence of fructose in the diet prevented any increase in insulin receptor number.

  19. Dairy Product Consumption Interacts with Glucokinase (GCK Gene Polymorphisms Associated with Insulin Resistance

    Directory of Open Access Journals (Sweden)

    Marine S. Da Silva

    2017-08-01

    Full Text Available Dairy product intake and a person’s genetic background have been reported to be associated with the risk of type 2 diabetes (T2D. The objective of this study was to examine the interaction between dairy products and genes related to T2D on glucose-insulin homeostasis parameters. A validated food frequency questionnaire, fasting blood samples, and glucokinase (GCK genotypes were analyzed in 210 healthy participants. An interaction between rs1799884 in GCK and dairy intake on the homeostasis model assessment of insulin resistance was identified. Secondly, human hepatocellular carcinoma cells (HepG2 were grown in a high-glucose medium and incubated with either 1-dairy proteins: whey, caseins, and a mixture of whey and casein; and 2-four amino acids (AA or mixtures of AA. The expression of GCK-related genes insulin receptor substrate-1 (IRS-1 and fatty acid synthase (FASN was increased with whey protein isolate or hydrolysate. Individually, leucine increased IRS-1 expression, whereas isoleucine and valine decreased FASN expression. A branched-chain AA mixture decreased IRS-1 and FASN expression. In conclusion, carriers of the A allele for rs1799884 in the GCK gene may benefit from a higher intake of dairy products to maintain optimal insulin sensitivity. Moreover, the results show that whey proteins affect the expression of genes related to glucose metabolism.

  20. Expression, receptor binding, and biophysical characterization of guinea pig insulin desB30

    DEFF Research Database (Denmark)

    Engholm, Ebbe; Hansen, Thomas Hesselhøj; Johansson, Eva

    2015-01-01

    Here we report, for the first time, the heterologous expression of desB30 guinea pig insulin (GI desB30) in the yeast Saccharomyces cerevisiae. The affinities of GI desB30 for the insulin receptor A and the IGF-I receptor were also quantified for the first time. Small-angle X-ray scattering...

  1. Changes in erythrocyte insulin receptors in normal dogs and keeshond dogs with inheritable, early onset, insulin dependent diabetes mellitus

    International Nuclear Information System (INIS)

    Klaassen, J.K.

    1986-01-01

    Validation of a procedure to evaluate insulin receptors on erythrocytes (RBC-IR) in dogs is described. The specific binding of ( 125 I)iodoinsulin to RBC-IR of normal dogs is significantly greater than binding in keeshonds with an inheritable form of early onset diabetes mellitus. This decreased binding was due to a significant decrease in RBC-IR affinity in the diabetic keeshonds. To determine the effect on RBC-IR, normal dogs were treated with either dexamethasone (0.1 mg/kg) or prednisone (0.3 mg/kg) for 10 days: concentrations of plasma cortisol, glucose, and insulin, plus binding characteristics of RBC-IR were determined. In the dexamethasone treated group, plasma glucose concentrations were elevated significantly by day 6 and continued through day 10. Insulin concentrations were elevated significantly by day 3 and remained elevated through day 10. In the prednisone treated group, glucose concentrations were elevated significantly by day 3, while insulin concentrations were elevated significantly by day 8. Maximum binding of RBC-IR was unaffected by prednisone and neither affinities nor receptor numbers were significantly different from day 1. No changes in plasma cortisol concentration were seen. Diabetic keeshonds on daily insulin treatment were removed from exogenous insulin therapy for 48 hours. Significant increases in glucose concentrations were observed, but no significant changes in cortisol, insulin, average receptor binding affinity, or RBC-IR number per cell occurred

  2. Phorbol ester-induced serine phosphorylation of the insulin receptor decreases its tyrosine kinase activity.

    Science.gov (United States)

    Takayama, S; White, M F; Kahn, C R

    1988-03-05

    The effect of 12-O-tetradecanoylphorbol-13-acetate (TPA) on the function of the insulin receptor was examined in intact hepatoma cells (Fao) and in solubilized extracts purified by wheat germ agglutinin chromatography. Incubation of ortho[32P]phosphate-labeled Fao cells with TPA increased the phosphorylation of the insulin receptor 2-fold after 30 min. Analysis of tryptic phosphopeptides from the beta-subunit of the receptor by reverse-phase high performance liquid chromatography and determination of their phosphoamino acid composition suggested that TPA predominantly stimulated phosphorylation of serine residues in a single tryptic peptide. Incubation of the Fao cells with insulin (100 nM) for 1 min stimulated 4-fold the phosphorylation of the beta-subunit of the insulin receptor. Prior treatment of the cells with TPA inhibited the insulin-stimulated tyrosine phosphorylation by 50%. The receptors extracted with Triton X-100 from TPA-treated Fao cells and purified on immobilized wheat germ agglutinin retained the alteration in kinase activity and exhibited a 50% decrease in insulin-stimulated tyrosine autophosphorylation and phosphotransferase activity toward exogenous substrates. This was due primarily to a decrease in the Vmax for these reactions. TPA treatment also decreased the Km of the insulin receptor for ATP. Incubation of the insulin receptor purified from TPA-treated cells with alkaline phosphatase decreased the phosphate content of the beta-subunit to the control level and reversed the inhibition, suggesting that the serine phosphorylation of the beta-subunit was responsible for the decreased tyrosine kinase activity. Our results support the notion that the insulin receptor is a substrate for protein kinase C in the Fao cell and that the increase in serine phosphorylation of the beta-subunit of the receptor produced by TPA treatment inhibited tyrosine kinase activity in vivo and in vitro. These data suggest that protein kinase C may regulate the function

  3. Decreased autophosphorylation of EGF receptor in insulin-deficient diabetic rats

    International Nuclear Information System (INIS)

    Okamoto, M.; Kahn, C.R.; Maron, R.; White, M.F.

    1988-01-01

    The authors have previously reported that despite an increase in receptor concentration, there is a decrease in autophosphorylation and tyrosine kinase activity of the insulin receptor in insulin-deficient diabetic rats. To determine if other tyrosine kinases might be altered, they have studied the epidermal growth factor (EGF) receptor kinase in wheat germ agglutinin-purified, Triton X-100-solubilized liver membranes from streptozotocin (STZ)-induced diabetic rats and the insulin-deficient BB rat. They find that autophosphorylation of EGF receptor is decreased in proportion to the severity of the diabetic state in STZ rats with a maximal decrease of 67%. A similar decrease in autophosphorylation was observed in diabetic BB rats that was partially normalized by insulin treatment. Separation of tryptic phosphopeptides by reverse-phase high-performance liquid chromatography revealed a decrease in labeling at all sites of autophosphorylation. A parallel decrease in EGF receptor phosphorylation was also found by immunoblotting with an antiphosphotyrosine antibody. EGF receptor concentration, determined by Scatchard analysis of 125 I-labeled EGF binding, was decreased by 39% in the STZ rat and 27% in the diabetic BB rat. Thus autophosphorylation of EGF receptor, like that of the insulin receptor, is decreased in insulin-deficient rat liver. In the case of EGF receptor, this is due in part to a decrease in receptor number and in part to a decrease in the specific activity of the kinase

  4. Effect of Scoparia dulcis extract on insulin receptors in streptozotocin induced diabetic rats: studies on insulin binding to erythrocytes.

    Science.gov (United States)

    Pari, Leelavinothan; Latha, Muniappan; Rao, Chippada Appa

    2004-01-01

    We investigated the insulin-receptor-binding effect of Scoparia dulcis plant extract in streptozotocin (STZ)-induced male Wistar rats, using circulating erythrocytes (ER) as a model system. An aqueous extract of S dulcis plant (SPEt) (200 mg/kg body weight) was administered orally. We measured blood levels of glucose and plasma insulin and the binding of insulin to cell-membrane ER receptors. Glibenclamide was used as standard reference drug. The mean specific binding of insulin to ER was significantly lower in diabetic control rats (DC) (55.0 +/- 2.8%) than in SPEt-treated (70.0 +/- 3.5%)- and glibenclamide-treated (65.0 +/- 3.3%) diabetic rats, resulting in a significant decrease in plasma insulin. Scatchard plot analysis demonstrated that the decrease in insulin binding was accounted for by a lower number of insulin receptor sites per cell in DC rats when compared with SPEt- and glibenclamide-treated rats. High-affinity (Kd1), low-affinity (Kd2), and kinetic analysis revealed an increase in the average receptor affinity in ER from SPEt and glibenclamide treated diabetic rats having 2.5 +/- 0.15 x 10(10) M(-1) (Kd1); 17.0 +/- 1.0 x 10(-8) M(-1) (Kd2), and 2.0 +/- 0.1 x 10(-10) M(-1) (Kd1); 12.3 +/- 0.9 x 10(-8) M(-1) (Kd2) compared with 1.0 +/- 0.08 x 10(-10) M(-1) (Kd1); 2.7 +/- 0.25 x 10(-8) M(-1) (Kd2) in DC rats. The results suggest an acute alteration in the number of insulin receptors on ER membranes in STZ-induced diabetic rats. Treatment with SPEt and glibenclamide significantly improved specific insulin binding, with receptor number and affinity binding (p < 0.001) reaching almost normal non-diabetic levels. The data presented here show that SPEt and glibenclamide increase total ER membrane insulin binding sites with a concomitant significant increase in plasma insulin.

  5. Biphasic modulation of insulin receptor substrate-1 during goitrogenesis

    Directory of Open Access Journals (Sweden)

    R. Grozovsky

    2007-05-01

    Full Text Available Insulin receptor substrate-1 (IRS-1 is the main intracellular substrate for both insulin and insulin-like growth factor I (IGF-I receptors and is critical for cell mitogenesis. Thyrotropin is able to induce thyroid cell proliferation through the cyclic AMP intracellular cascade; however, the presence of either insulin or IGF-I is required for the mitogenic effect of thyroid-stimulating hormone (TSH to occur. The aim of the present study was to determine whether thyroid IRS-1 content is modulated by TSH in vivo. Strikingly, hypothyroid goitrous rats, which have chronically high serum TSH levels (control, C = 2.31 ± 0.28; methimazole (MMI 21d = 51.02 ± 6.02 ng/mL, N = 12 rats, when treated with 0.03% MMI in drinking water for 21 days, showed significantly reduced thyroid IRS-1 mRNA content. Since goiter was already established in these animals by MMI for 21 days, we also evaluated IRS-1 expression during goitrogenesis. Animals treated with MMI for different periods of time showed a progressive increase in thyroid weight (C = 22.18 ± 1.21; MMI 5d = 32.83 ± 1.48; MMI 7d = 31.1 ± 3.25; MMI 10d = 33.8 ± 1.25; MMI 14d = 45.5 ± 2.56; MMI 18d = 53.0 ± 3.01; MMI 21d = 61.9 ± 3.92 mg, N = 9-15 animals per group and serum TSH levels (C = 1.57 ± 0.2; MMI 5d = 9.95 ± 0.74; MMI 7d = 10.38 ± 0.84; MMI 10d = 17.72 ± 1.47; MMI 14d = 25.65 ± 1.23; MMI 18d = 35.38 ± 3.69; MMI 21d = 31.3 ± 2.7 ng/mL, N = 9-15 animals per group. Thyroid IRS-1 mRNA expression increased progressively during goitrogenesis, being significantly higher by the 14th day of MMI treatment, and then started to decline, reaching the lowest values by the 21st day, when a significant reduction was detected. In the liver of these animals, however, a significant decrease of IRS-1 mRNA was detected after 14 days of MMI treatment, a mechanism probably involved in the insulin resistance that occurs in hypothyroidism. The increase in IRS-1 expression during goitrogenesis may represent an

  6. Nigella sativa Relieves the Altered Insulin Receptor Signaling in Streptozotocin-Induced Diabetic Rats Fed with a High-Fat Diet.

    Science.gov (United States)

    Balbaa, Mahmoud; El-Zeftawy, Marwa; Ghareeb, Doaa; Taha, Nabil; Mandour, Abdel Wahab

    2016-01-01

    The black cumin (Nigella sativa) "NS" or the black seeds have many pharmacological activities such as antioxidant, anticarcinogenic, antihypertensive, and antidiabetic properties. In this work, streptozotocin-induced diabetic rats fed with a high-fat diet were treated daily with NS oil (NSO) in order to study the effect on the blood glucose, lipid profile, oxidative stress parameters, and the gene expression of some insulin receptor-induced signaling molecules. This treatment was combined also with some drugs (metformin and glimepiride) and the insulin receptor inhibitor I-OMe-AG538. The administration of NSO significantly induced the gene expression of insulin receptor compared to rats that did not receive NSO. Also, it upregulated the expression of insulin-like growth factor-1 and phosphoinositide-3 kinase, whereas the expression of ADAM-17 was downregulated. The expression of ADAM-17 is corroborated by the analysis of TIMP-3 content. In addition, the NSO significantly reduced blood glucose level, components of the lipid profile, oxidative stress parameters, serum insulin/insulin receptor ratio, and the tumor necrosis factor-α, confirming that NSO has an antidiabetic activity. Thus, the daily NSO treatment in our rat model indicates that NSO has a potential in the management of diabetes as well as improvement of insulin-induced signaling.

  7. Nigella sativa Relieves the Altered Insulin Receptor Signaling in Streptozotocin-Induced Diabetic Rats Fed with a High-Fat Diet

    Directory of Open Access Journals (Sweden)

    Mahmoud Balbaa

    2016-01-01

    Full Text Available The black cumin (Nigella sativa “NS” or the black seeds have many pharmacological activities such as antioxidant, anticarcinogenic, antihypertensive, and antidiabetic properties. In this work, streptozotocin-induced diabetic rats fed with a high-fat diet were treated daily with NS oil (NSO in order to study the effect on the blood glucose, lipid profile, oxidative stress parameters, and the gene expression of some insulin receptor-induced signaling molecules. This treatment was combined also with some drugs (metformin and glimepiride and the insulin receptor inhibitor I-OMe-AG538. The administration of NSO significantly induced the gene expression of insulin receptor compared to rats that did not receive NSO. Also, it upregulated the expression of insulin-like growth factor-1 and phosphoinositide-3 kinase, whereas the expression of ADAM-17 was downregulated. The expression of ADAM-17 is corroborated by the analysis of TIMP-3 content. In addition, the NSO significantly reduced blood glucose level, components of the lipid profile, oxidative stress parameters, serum insulin/insulin receptor ratio, and the tumor necrosis factor-α, confirming that NSO has an antidiabetic activity. Thus, the daily NSO treatment in our rat model indicates that NSO has a potential in the management of diabetes as well as improvement of insulin-induced signaling.

  8. 4PS/insulin receptor substrate (IRS)-2 is the alternative substrate of the insulin receptor in IRS-1-deficient mice.

    Science.gov (United States)

    Patti, M E; Sun, X J; Bruening, J C; Araki, E; Lipes, M A; White, M F; Kahn, C R

    1995-10-20

    Insulin receptor substrate-1 (IRS-1) is the major cytoplasmic substrate of the insulin and insulin-like growth factor (IGF)-1 receptors. Transgenic mice lacking IRS-1 are resistant to insulin and IGF-1, but exhibit significant residual insulin action which corresponds to the presence of an alternative high molecular weight substrate in liver and muscle. Recently, Sun et al. (Sun, X.-J., Wang, L.-M., Zhang, Y., Yenush, L. P., Myers, M. G., Jr., Glasheen, E., Lane, W.S., Pierce, J. H., and White, M. F. (1995) Nature 377, 173-177) purified and cloned 4PS, the major substrate of the IL-4 receptor-associated tyrosine kinase in myeloid cells, which has significant structural similarity to IRS-1. To determine if 4PS is the alternative substrate of the insulin receptor in IRS-1-deficient mice, we performed immunoprecipitation, immunoblotting, and phosphatidylinositol (PI) 3-kinase assays using specific antibodies to 4PS. Following insulin stimulation, 4PS is rapidly phosphorylated in liver and muscle, binds to the p85 subunit of PI 3-kinase, and activates the enzyme. Insulin stimulation also results in the association of 4PS with Grb 2 in both liver and muscle. In IRS-1-deficient mice, both the phosphorylation of 4PS and associated PI 3-kinase activity are enhanced, without an increase in protein expression. Immunodepletion of 4PS from liver and muscle homogenates removes most of the phosphotyrosine-associated PI 3-kinase activity in IRS-1-deficient mice. Thus, 4PS is the primary alternative substrate, i.e. IRS-2, which plays a major role in physiologic insulin signal transduction via both PI 3-kinase activation and Grb 2/Sos association. In IRS-1-deficient mice, 4PS/IRS-2 provides signal transduction to these two major pathways of insulin signaling.

  9. Association between Insulin Like Growth Factor-1 (IGF-1) gene ...

    African Journals Online (AJOL)

    The insulin-like growth factor-1 (IGF1) is a key regulator of muscle development and metabolism in birds and other vertebrate. Our objective was to determine the association between IGF1 gene polymorphism and carcass traits in FUNAAB Alpha chicken. Genomic DNA was extracted from the blood of 50 normal feathered ...

  10. Receptor-mediated photo-cytotoxicity: synthesis of a photoactivatable psoralen derivative conjugated to insulin.

    Science.gov (United States)

    Gasparro, F P; Knobler, R M; Yemul, S S; Bisaccia, E; Edelson, R L

    1986-12-15

    4'-Aminomethyl-4,5',8-trimethylpsoralen has been chemically conjugated to insulin using a carbodiimide derivative. The psoralen moiety retains its photochemical reactivity as evidenced by its ability to crosslink DNA after exposure to long wavelength ultraviolet light (UVA, 320-400 nm). This chimeric molecule has been used to selectively kill a population of lymphocytes whose expression of insulin receptors has been stimulated with phytohemagglutinin. Insulin carries the psoralen into the cell via receptor-mediated endocytosis, where it is subsequently activated by exposure to UVA light. The UVA induced activity of AMT-insulin can be blocked by the presence of native insulin. The viability of unstimulated lymphocytes was not affected by AMT-insulin and UVA light. The hybrid insulin-psoralen molecule may be a prototype for a family of phototoxic drugs which can be selectively delivered to subsets of lymphocytes.

  11. Identification and characterization of insulin receptors in basolateral membranes of dog intestinal mucosa

    International Nuclear Information System (INIS)

    Gingerich, R.L.; Gilbert, W.R.; Comens, P.G.; Gavin, J.R. III

    1987-01-01

    Little is known about hormonal regulation of substrate transport and metabolism in the mucosal lining of the small intestine. Because insulin regulates these functions in other tissues by binding to its receptor, we have investigated the presence of insulin receptors in canine small intestinal mucosa with basolateral membranes (BLM) and brush border membranes (BBM) prepared by sorbitol density centrifugation. A14-[ 125 I]iodoinsulin was used to study binding and structural characteristics of specific insulin receptors in BLM. Analysis of receptors in BLM identified binding sites with high affinity (Kd 88 pM) and low capacity (0.4 pmol/mg protein) as well as with low affinity (Kd 36 nM) and high capacity (4.7 pmol/mg protein). Binding was time, temperature, and pH dependent, and 125 I-labeled insulin dissociation was enhanced in the presence of unlabeled insulin. Cross-reactivity of these receptors to proinsulin, IGF-II, and IGF-I was 4, 1.8, and less than 1%, respectively. Covalent cross-linking of labeled insulin to BLM insulin receptors with disuccinimidyl suberate revealed a single 135,000-Mr band that was completely inhibited by unlabeled insulin. There was a 16-fold greater specific binding of insulin to BLM (39.0 +/- 2.4%) than to BBM (2.5 +/- 0.6%). These results demonstrate the presence of a highly specific receptor for insulin on the vascular, but not the luminal, surface of the small intestinal mucosa in dogs, and suggest that insulin may play an important role in the regulation of gastrointestinal physiology

  12. Autoimmune Hypoglycemia in a Patient with Characterization of Insulin Receptor Autoantibodies

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    Suk Chon

    2011-02-01

    Full Text Available BackgroundType B insulin resistance syndrome is a manifestation of autoantibodies to the insulin receptor that results in severe hyperglycemia and acanthosis nigricans. However, the mechanisms by which these autoantibodies induce hypoglycemia are largely unknown. In this paper, we report the case of patient with type B insulin resistance syndrome who presented with frequent severe fasting hypoglycemia and acanthosis nigricans.MethodsTo evaluate the mechanism of hypoglycemia, we measured the inhibition of insulin binding to erythrocytes and IM9 lymphocytes in a sample of the patient's dialyzed serum before and after immunosuppressive therapy.ResultsIn the patient's pre-treatment serum IgG, the binding of 125I-insulin to erythrocytes was markedly inhibited in a dose-dependent manner until the cold insulin level reached 10-9 mol/L. We also observed dose-dependent inhibition of insulin binding to IM9 lymphocytes, which reached approximately 82% inhibition and persisted even when diluted 1:20. After treatment with glucocorticoids, insulin-erythrocyte binding activity returned to between 70% and 80% of normal, while the inhibition of insulin-lymphocyte binding was reduced by 17%.ConclusionWe treated a patient with type B insulin resistance syndrome showing recurrent fasting hypoglycemia with steroids and azathioprine. We characterized the patient's insulin receptor antibodies by measuring the inhibition of insulin binding.

  13. A nonsense mutation causing decreased levels of insulin receptor mRNA: Detection by a simplified technique for direct sequencing of genomic DNA amplified by the polymerase chain reaction

    International Nuclear Information System (INIS)

    Kadowaki, T.; Kadowaki, H.; Taylor, S.I.

    1990-01-01

    Mutations in the insulin receptor gene can render the cell resistant to the biological action of insulin. The authors have studied a patient with leprechaunism (leprechaun/Minn-1), a genetic syndrome associated with intrauterine growth retardation and extreme insulin resistance. Genomic DNA from the patient was amplified by the polymerase chain reaction catalyzed by Thermus aquaticus (Taq) DNA polymerase, and the amplified DNA was directly sequenced. A nonsense mutations was identified at codon 897 in exon 14 in the paternal allele of the patient's insulin receptor gene. Levels of insulin receptor mRNA are decreased to <10% of normal in Epstein-Barr virus-transformed lymphoblasts and cultured skin fibroblasts from this patient. Thus, this nonsense mutation appears to cause a decrease in the levels of insulin receptor mRNA. In addition, they have obtained indirect evidence that the patient's maternal allele of the insulin receptor gene contains a cis-acting dominant mutation that also decreases the level of mRNA, but by a different mechanism. The nucleotide sequence of the entire protein-coding domain and the sequences of the intron-exon boundaries for all 22 exons of the maternal allele were normal. Presumably, the mutation in the maternal allele maps elsewhere in the insulin receptor gene. Thus, they conclude that the patient is a compound heterozygote for two cis-acting dominant mutations in the insulin receptor gene: (i) a nonsense mutation in the paternal allel that reduces the level of insulin receptor mRNA and (ii) an as yet unidentified mutation in the maternal allele that either decreases the rate of transcription or decreases the stability of the mRNA

  14. Site-Directed Mutagenesis of the Fibronectin Domains in Insulin Receptor-Related Receptor

    Directory of Open Access Journals (Sweden)

    Igor E. Deyev

    2017-11-01

    Full Text Available The orphan insulin receptor-related receptor (IRR, in contrast to its close homologs, the insulin receptor (IR and insulin-like growth factor receptor (IGF-IR can be activated by mildly alkaline extracellular medium. We have previously demonstrated that IRR activation is defined by its extracellular region, involves multiple domains, and shows positive cooperativity with two synergistic sites. By the analyses of point mutants and chimeras of IRR with IR in, we now address the role of the fibronectin type III (FnIII repeats in the IRR pH-sensing. The first activation site includes the intrinsically disordered subdomain ID (646–716 within the FnIII-2 domain at the C-terminus of IRR alpha subunit together with closely located residues L135, G188, R244, H318, and K319 of L1 and C domains of the second subunit. The second site involves residue T582 of FnIII-1 domain at the top of IRR lambda-shape pyramid together with M406, V407, and D408 from L2 domain within the second subunit. A possible importance of the IRR carbohydrate moiety for its activation was also assessed. IRR is normally less glycosylated than IR and IGF-IR. Swapping both FnIII-2 and FnIII-3 IRR domains with those of IR shifted beta-subunit mass from 68 kDa for IRR to about 100 kDa due to increased glycosylation and abolished the IRR pH response. However, mutations of four asparagine residues, potential glycosylation sites in chimera IRR with swapped FnIII-2/3 domains of IR, decreased the chimera glycosylation and resulted in a partial restoration of IRR pH-sensing activity, suggesting that the extensive glycosylation of FnIII-2/3 provides steric hindrance for the alkali-induced rearrangement of the IRR ectodomain.

  15. Elevation of serum insulin concentration during euglycemic hyperinsulinemic clamp studies leads to similar activation of insulin receptor kinase in skeletal muscle of subjects with and without NIDDM

    DEFF Research Database (Denmark)

    Klein, H H; Vestergaard, H; Kotzke, G

    1995-01-01

    The role of skeletal muscle insulin receptor kinase in the pathogenesis of non-insulin-dependent diabetes mellitus (NIDDM) was investigated. Muscle biopsies from 13 patients with NIDDM and 10 control subjects at fasting serum insulin concentrations and approximately 1,000 pmol/l steady-state serum...... insulin during euglycemic hyperinsulinemic clamps were immediately frozen. The biopsies were then solubilized, and the receptors were immobilized to anti-insulin receptor antibody-coated microwells. Receptor kinase and binding activities were consecutively measured in these wells. The increase in serum...... and control groups, respectively). Moreover, by selecting only the receptors that bound to anti-phosphotyrosine antibody, we found similar hyperinsulinemia-induced increases of this receptor fraction and its kinase activity in both study groups. In vitro activation of the immobilized receptors with 2 mmol...

  16. β1-adrenergic receptor stimulation by agonist Compound 49b restores insulin receptor signal transduction in vivo

    Science.gov (United States)

    Jiang, Youde; Zhang, Qiuhua; Ye, Eun-Ah

    2014-01-01

    Purpose Determine whether Compound 49b treatment ameliorates retinal changes due to the lack of β2-adrenergic receptor signaling. Methods Using retinas from 3-month-old β2-adrenergic receptor-deficient mice, we treated mice with our novel β1-/β2-adrenergic receptor agonist, Compound 49b, to assess the effects of adrenergic agonists acting only on β1-adrenergic receptors due to the absence of β2-adrenergic receptors. Western blotting or enzyme-linked immunosorbent assay (ELISA) analyses were performed for β1- and β2-adrenergic receptors, as well as key insulin resistance proteins, including TNF-α, SOCS3, IRS-1Ser307, and IRTyr960. Analyses were also performed on key anti- and proapoptotic proteins: Akt, Bcl-xL, Bax, and caspase 3. Electroretinogram analyses were conducted to assess functional changes, while histological assessment was conducted for changes in retinal thickness. Results A 2-month treatment of β2-adrenergic receptor-deficient mice with daily eye drops of 1 mM Compound 49b, a novel β1- and β2-adrenergic receptor agonist, reversed the changes in insulin resistance markers (TNF-α and SOCS3) observed in untreated β2-adrenergic receptor-deficient mice, and concomitantly increased morphological integrity (retinal thickness) and functional responses (electroretinogram amplitude). These results suggest that stimulating β1-adrenergic receptors on retinal endothelial cells or Müller cells can compensate for the loss of β2-adrenergic receptor signaling on Müller cells, restore insulin signal transduction, reduce retinal apoptosis, and enhance retinal function. Conclusions Since our previous studies with β1-adrenergic receptor knockout mice confirmed that the reverse also occurs (β2-adrenergic receptor stimulation can compensate for the loss of β1-adrenergic receptor activity), it appears that increased activity in either of these pathways alone is sufficient to block insulin resistance–based retinal cell apoptosis. PMID:24966659

  17. Localization of insulin receptor mRNA in rat brain by in situ hybridization

    International Nuclear Information System (INIS)

    Marks, J.L.; Porte, D. Jr.; Stahl, W.L.; Baskin, D.G.

    1990-01-01

    Insulin receptor mRNA was demonstrated in rat brain slices by in situ hybridization with three 35 S-oligonucleotide probes and contact film autoradiography. Specificity was confirmed by showing that (a) excess unlabeled probe abolished the signal, (b) an oligonucleotide probe for rat neuropeptide Y mRNA showed a different distribution of hybridization signal, and (c) the distribution of insulin receptor binding was consistent with the distribution of insulin receptor mRNA. Insulin receptor mRNA was most abundant in the granule cell layers of the olfactory bulb, cerebellum and dentate gyrus, in the pyramidal cell body layers of the pyriform cortex and hippocampus, in the choroid plexus and in the arcuate nucleus of the hypothalamus

  18. Hepatocyte Toll-like receptor 4 regulates obesity-induced inflammation and insulin resistance

    Science.gov (United States)

    Chronic low-grade inflammation is a hallmark of obesity and thought to contribute to the development of obesity-related insulin resistance. Toll-like receptor 4 (Tlr4) is a key mediator of pro-inflammatory responses. Mice lacking Tlr4s are protected from diet-induced insulin resistance and inflammat...

  19. Insulin signaling inhibits the 5-HT2C receptor in choroid plexus via MAP kinase

    Directory of Open Access Journals (Sweden)

    Guan Kunliang

    2003-06-01

    Full Text Available Abstract Background G protein-coupled receptors (GPCRs interact with heterotrimeric GTP-binding proteins (G proteins to modulate acute changes in intracellular messenger levels and ion channel activity. In contrast, long-term changes in cellular growth, proliferation and differentiation are often mediated by tyrosine kinase receptors and certain GPCRs by activation of mitogen-activated protein (MAP kinases. Complex interactions occur between these signaling pathways, but the specific mechanisms of such regulatory events are not well-understood. In particular it is not clear whether GPCRs are modulated by tyrosine kinase receptor-MAP kinase pathways. Results Here we describe tyrosine kinase receptor regulation of a GPCR via MAP kinase. Insulin reduced the activity of the 5-HT2C receptor in choroid plexus cells which was blocked by the MAP kinase kinase (MEK inhibitor, PD 098059. We demonstrate that the inhibitory effect of insulin and insulin-like growth factor type 1 (IGF-1 on the 5-HT2C receptor is dependent on tyrosine kinase, RAS and MAP kinase. The effect may be receptor-specific: insulin had no effect on another GPCR that shares the same G protein signaling pathway as the 5-HT2C receptor. This effect is also direct: activated MAP kinase mimicked the effect of insulin, and removing a putative MAP kinase site from the 5-HT2C receptor abolished the effect of insulin. Conclusion These results show that insulin signaling can inhibit 5-HT2C receptor activity and suggest that MAP kinase may play a direct role in regulating the function of a specific GPCR.

  20. Differential Effects of Camel Milk on Insulin Receptor Signaling – Towards Understanding the Insulin-like Properties of Camel Milk

    Directory of Open Access Journals (Sweden)

    Abdulrasheed O Abdulrahman

    2016-01-01

    Full Text Available Previous studies on the Arabian camel (Camelus dromedarius showed beneficial effects of its milk reported in diverse models of human diseases including a substantial hypoglycemic activity. However, the cellular and molecular mechanisms involved in such effects remain completely unknown. In this study, we hypothesized that camel milk may act at the level of human insulin receptor (hIR and its related intracellular signaling pathways. Therefore, we examined the effect of camel milk on the activation of hIR transiently expressed in human embryonic kidney 293 (HEK293 cells using bioluminescence resonance energy transfer (BRET technology. BRET was used to assess, in live cells and real-time, the physical interaction between hIR and insulin receptor signaling proteins (IRS1 and the growth factor receptor-bound protein 2 (Grb2. Our data showed that camel milk did not promote any increase in the BRET signal between hIR and IRS1 or Grb2 in the absence of insulin stimulation. However, it significantly potentiated the maximal insulin-promoted BRET signal between hIR and Grb2 but not IRS1. Interestingly, camel milk appears to differentially impact the downstream signaling since it significantly activated ERK1/2 and potentiated the insulin-induced ERK1/2 but not Akt activation. These observations are to some extent consistent with the BRET data since ERK1/2 and Akt activation are known to reflect the engagement of Grb2 and IRS1 pathways, respectively. The preliminary fractionation of camel milk suggests the peptide/protein nature of the active component in camel milk. Together, our study demonstrates for the first time an allosteric effect of camel milk on insulin receptor conformation and activation with differential effects on its intracellular signaling. These findings should help to shed more light on the hypoglycemic activity of camel milk with potential therapeutic applications.

  1. Characterization of a second ligand binding site of the insulin receptor

    International Nuclear Information System (INIS)

    Hao Caili; Whittaker, Linda; Whittaker, Jonathan

    2006-01-01

    Insulin binding to its receptor is characterized by high affinity, curvilinear Scatchard plots, and negative cooperativity. These properties may be the consequence of binding of insulin to two receptor binding sites. The N-terminal L1 domain and the C-terminus of the α subunit contain one binding site. To locate a second site, we examined the binding properties of chimeric receptors in which the L1 and L2 domains and the first Fibronectin Type III repeat of the insulin-like growth factor-I receptor were replaced by corresponding regions of the insulin receptor. Substitutions of the L2 domain and the first Fibronectin Type III repeat together with the L1 domain produced 80- and 300-fold increases in affinity for insulin. Fusion of these domains to human immunoglobulin Fc fragment produced a protein which bound insulin with a K d of 2.9 nM. These data strongly suggest that these domains contain an insulin binding site

  2. Antibodies to the α-subunit of insulin receptor from eggs of immunized hens

    International Nuclear Information System (INIS)

    Song, C.; Yu, J.; Bai, D.H.; Hester, P.Y.; Kim, K.

    1985-01-01

    Simple methods for the generation, purification, and assay of antibodies to the α-subunit of insulin receptor from eggs of immunized hen have been described. Chicken antibodies against the α-subunit inhibit insulin binding to the receptor and stimulate glucose oxidation as well as autophosphorylation of the β-subunit. Thus the properties of chicken antibodies are very similar to those of antibodies found in human autoimmune diseases and different from rabbit antibodies obtained against the same antigen

  3. Designing peptide inhibitor of insulin receptor to induce diabetes mellitus type 2 in animal model Mus musculus.

    Science.gov (United States)

    Permatasari, Galuh W; Utomo, Didik H; Widodo

    2016-10-01

    A designing peptide as agent for inducing diabetes mellitus type 2 (T2DM) in an animal model is challenging. The computational approach provides a sophisticated tool to design a functional peptide that may block the insulin receptor activity. The peptide that able to inhibit the binding between insulin and insulin receptor is a warrant for inducing T2DM. Therefore, we designed a potential peptide inhibitor of insulin receptor as an agent to generate T2DM animal model by bioinformatics approach. The peptide has been developed based on the structure of insulin receptor binding site of insulin and then modified it to obtain the best properties of half life, hydrophobicity, antigenicity, and stability binding into insulin receptor. The results showed that the modified peptide has characteristics 100h half-life, high-affinity -95.1±20, and high stability 28.17 in complex with the insulin receptor. Moreover, the modified peptide has molecular weight 4420.8g/Mol and has no antigenic regions. Based on the molecular dynamic simulation, the complex of modified peptide-insulin receptor is more stable than the commercial insulin receptor blocker. This study suggested that the modified peptide has the promising performance to block the insulin receptor activity that potentially induce diabetes mellitus type 2 in mice. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Insulin receptor isoforms A and B as well as insulin receptor substrates-1 and -2 are differentially expressed in prostate cancer.

    Science.gov (United States)

    Heni, Martin; Hennenlotter, Jörg; Scharpf, Marcus; Lutz, Stefan Z; Schwentner, Christian; Todenhöfer, Tilman; Schilling, David; Kühs, Ursula; Gerber, Valentina; Machicao, Fausto; Staiger, Harald; Häring, Hans-Ulrich; Stenzl, Arnulf

    2012-01-01

    In different cancers types, insulin receptor isoform composition or insulin receptor substrate (IRS) isoforms are different to healthy tissue. This may be a molecular link to increased cancer risk in diabetes and obesity. Since this is yet unclear for prostate cancer, we investigated IR isoform composition and IRS balance in prostate cancer compared to benign and tumor adjacent benign prostate tissue and brought this into relation to cell proliferation. We studied 23 benign prostate samples from radical cystectomy or benign prostatic hyperplasia surgery, 30 samples from benign tissue directly adjacent to prostate cancer foci and 35 cancer samples from different patients. RNA expression levels for insulin receptor isoforms A and B, IRS-1, IRS-2, and IGF-1 receptor were assessed by quantitative real-time RT-PCR. In addition, RNA- and protein expression of the cell cycle regulator p27(Kip1) was quantified by real-time RT-PCR and immunohistochemistry. Insulin receptor isoform A to B ratio was significantly higher in cancer as well as in tumor adjacent benign prostate tissue compared to purely benign prostates (pprostatic tissue (pcancer and adjacent tissue were significantly associated with reduced p27(Kip1) content (preceptor levels were significantly lower in patients with type 2 diabetes (p = 0.0019). We found significant differences in the insulin signaling cascade between benign prostate tissue and prostate cancer. Histological benign tissue adjacent to cancer showed expression patterns similar to the malignancies. Our findings suggest a role of the insulin signaling pathway in prostate cancer and surrounding tissue and can hence be relevant for both novel diagnostic and therapeutic approaches in this malignancy.

  5. Peroxisome Proliferator-Activated Receptors and Hepatitis C Virus-Induced Insulin Resistance

    Directory of Open Access Journals (Sweden)

    Francesco Negro

    2009-01-01

    Full Text Available Insulin resistance and type 2 diabetes are associated with hepatitis C virus infection. A wealth of clinical and experimental data suggests that the virus is directly interfering with the insulin signalling in hepatocytes. In the case of at least one viral genotype (the type 3a, insulin resistance seems to be directly mediated by the downregulation of the peroxisome proliferator-activated receptor γ. Whether and how this interaction may be manipulated pharmacologically, in order to improve the responsiveness to antivirals of insulin resistant chronic hepatitis C, patients remain to be fully explored.

  6. Gene expression of insulin signal-transduction pathway intermediates is lower in rats fed a beef tallow diet than in rats fed a safflower oil diet.

    Science.gov (United States)

    Kim, Y B; Nakajima, R; Matsuo, T; Inoue, T; Sekine, T; Komuro, M; Tamura, T; Tokuyama, K; Suzuki, M

    1996-09-01

    To elucidate the effects of dietary fatty acid composition on the insulin signaling pathway, we measured the gene expression of the earliest steps in the insulin action pathway in skeletal muscle of rats fed a safflower oil diet or a beef tallow diet. Rats were meal-fed an isoenergetic diet based on either safflower oil or beef tallow for 8 weeks. Both diets provided 45%, 35%, and 20% of energy as fat, carbohydrate, and protein, respectively. Insulin resistance, assessed from the diurnal rhythm of plasma glucose and insulin and the oral glucose tolerance test (OGTT), developed in rats fed a beef tallow diet. Body fat content was greater in rats fed a beef tallow diet versus a safflower oil diet. The level of insulin receptor mRNA, relative expression of the insulin receptor mRNA isoforms, and receptor protein were not affected by the composition of dietary fatty acids. The abundance of insulin receptor substrate-1 (IRS-1) and phosphatidylinositol (PI) 3-kinase mRNA and protein was significantly lower in rats fed a beef tallow diet versus a safflower oil diet. We conclude that long-term feeding of a high-fat diet with saturated fatty acids induces decrease in IRS-1 and PI 3-kinase mRNA and protein levels, causing insulin resistance in skeletal muscle.

  7. Unique expression pattern of the three insulin receptor family members in the rat mammary gland

    DEFF Research Database (Denmark)

    Hvid, Henning; Klopfleisch, Robert; Vienberg, Sara Gry

    2011-01-01

    mammary gland. Using laser micro-dissection, quantitative RT-PCR and immunohistochemistry, we examined the expression of IR (insulin receptor), IGF-1R (IGF-1 receptor), IRR (insulin receptor-related receptor), ERα (estrogen receptor alpha), ERβ (estrogen receptor beta) and PR (progesteron receptor......) in young, virgin, female Sprague-Dawley rats and compared to expression in reference organs. The mammary gland displayed the highest expression of IRR and IGF-1R. In contrast, low expression of IR transcripts was observed in the mammary gland tissue with expression of the IR-A isoform being 5-fold higher...... than the expression of the IR-B. By immunohistochemistry, expression of IR and IGF-1R was detected in all mammary gland epithelial cells. Expression of ERα and PR was comparable between mammary gland and ovary, whereas expression of ERβ was lower in mammary gland than in the ovary. Finally, expression...

  8. Assembly of high-affinity insulin receptor agonists and antagonists from peptide building blocks

    Science.gov (United States)

    Schäffer, Lauge; Brissette, Renee E.; Spetzler, Jane C.; Pillutla, Renuka C.; Østergaard, Søren; Lennick, Michael; Brandt, Jakob; Fletcher, Paul W.; Danielsen, Gillian M.; Hsiao, Ku-Chuan; Andersen, Asser S.; Dedova, Olga; Ribel, Ulla; Hoeg-Jensen, Thomas; Hansen, Per Hertz; Blume, Arthur J.; Markussen, Jan; Goldstein, Neil I.

    2003-01-01

    Insulin is thought to elicit its effects by crosslinking the two extracellular α-subunits of its receptor, thereby inducing a conformational change in the receptor, which activates the intracellular tyrosine kinase signaling cascade. Previously we identified a series of peptides binding to two discrete hotspots on the insulin receptor. Here we show that covalent linkage of such peptides into homodimers or heterodimers results in insulin agonists or antagonists, depending on how the peptides are linked. An optimized agonist has been shown, both in vitro and in vivo, to have a potency close to that of insulin itself. The ability to construct such peptide derivatives may offer a path for developing agonists or antagonists for treatment of a wide variety of diseases. PMID:12684539

  9. High-Fat Diet Augments VPAC1 Receptor-Mediated PACAP Action on the Liver, Inducing LAR Expression and Insulin Resistance

    Directory of Open Access Journals (Sweden)

    Masanori Nakata

    2016-01-01

    Full Text Available Pituitary adenylate cyclase-activating polypeptide (PACAP acts on multiple processes of glucose and energy metabolism. PACAP potentiates insulin action in adipocytes and insulin release from pancreatic β-cells, thereby enhancing glucose tolerance. Contrary to these effects at organ levels, PACAP null mice exhibit hypersensitivity to insulin. However, this apparent discrepancy remains to be solved. We aimed to clarify the mechanism underlying the antidiabetic phenotype of PACAP null mice. Feeding with high-fat diet (HFD impaired insulin sensitivity and glucose tolerance in wild type mice, whereas these changes were prevented in PACAP null mice. HFD also impaired insulin-induced Akt phosphorylation in the liver in wild type mice, but not in PACAP null mice. Using GeneFishing method, HFD increased the leukocyte common antigen-related (LAR protein tyrosine phosphatase in the liver in wild type mice. Silencing of LAR restored the insulin signaling in the liver of HFD mice. Moreover, the increased LAR expression by HFD was prevented in PACAP null mice. HFD increased the expression of VPAC1 receptor (VPAC1-R, one of three PACAP receptors, in the liver of wild type mice. These data indicate that PACAP-VPAC1-R signaling induces LAR expression and insulin resistance in the liver of HFD mice. Antagonism of VPAC1-R may prevent progression of HFD-induced insulin resistance in the liver, providing a novel antidiabetic strategy.

  10. Oleanolic acid supplement attenuates liquid fructose-induced adipose tissue insulin resistance through the insulin receptor substrate-1/phosphatidylinositol 3-kinase/Akt signaling pathway in rats

    Energy Technology Data Exchange (ETDEWEB)

    Li, Ying [Faculty of Basic Medical Sciences, Chongqing Medical University, Chongqing 400016 (China); Wang, Jianwei, E-mail: wangjianwei1968@gmail.com [Department of Traditional Chinese Medicine, Chongqing Medical University, Chongqing 400016 (China); Gu, Tieguang [Endocrinology and Metabolism Group, Sydney Institute of Health Sciences, Sydney, NSW 2000 Australia (Australia); Yamahara, Johji [Pharmafood Institute, Kyoto 602-8136 (Japan); Li, Yuhao, E-mail: yuhao@sitcm.edu.au [Endocrinology and Metabolism Group, Sydney Institute of Health Sciences, Sydney, NSW 2000 Australia (Australia)

    2014-06-01

    Oleanolic acid, a triterpenoid contained in more than 1620 plants including various fruits and foodstuffs, has numerous metabolic effects, such as hepatoprotection. However, its underlying mechanisms remain poorly understood. Adipose tissue insulin resistance (Adipo-IR) may contribute to the development and progress of metabolic abnormalities through release of excessive free fatty acids from adipose tissue. This study investigated the effect of oleanolic acid on Adipo-IR. The results showed that supplement with oleanolic acid (25 mg/kg, once daily, by oral gavage) over 10 weeks attenuated liquid fructose-induced increase in plasma insulin concentration and the homeostasis model assessment of insulin resistance (HOMA-IR) index in rats. Simultaneously, oleanolic acid reversed the increase in the Adipo-IR index and plasma non-esterified fatty acid concentrations during the oral glucose tolerance test assessment. In white adipose tissue, oleanolic acid enhanced mRNA expression of the genes encoding insulin receptor, insulin receptor substrate (IRS)-1 and phosphatidylinositol 3-kinase. At the protein level, oleanolic acid upregulated total IRS-1 expression, suppressed the increased phosphorylated IRS-1 at serine-307, and restored the increased phosphorylated IRS-1 to total IRS-1 ratio. In contrast, phosphorylated Akt to total Akt ratio was increased. Furthermore, oleanolic acid reversed fructose-induced decrease in phosphorylated-Akt/Akt protein to plasma insulin concentration ratio. However, oleanolic acid did not affect IRS-2 mRNA expression. Therefore, these results suggest that oleanolic acid supplement ameliorates fructose-induced Adipo-IR in rats via the IRS-1/phosphatidylinositol 3-kinase/Akt pathway. Our findings may provide new insights into the mechanisms of metabolic actions of oleanolic acid. - Highlights: • Adipose insulin resistance (Adipo-IR) contributes to metabolic abnormalities. • We investigated the effect of oleanolic acid (OA) on adipo-IR in

  11. Oleanolic acid supplement attenuates liquid fructose-induced adipose tissue insulin resistance through the insulin receptor substrate-1/phosphatidylinositol 3-kinase/Akt signaling pathway in rats

    International Nuclear Information System (INIS)

    Li, Ying; Wang, Jianwei; Gu, Tieguang; Yamahara, Johji; Li, Yuhao

    2014-01-01

    Oleanolic acid, a triterpenoid contained in more than 1620 plants including various fruits and foodstuffs, has numerous metabolic effects, such as hepatoprotection. However, its underlying mechanisms remain poorly understood. Adipose tissue insulin resistance (Adipo-IR) may contribute to the development and progress of metabolic abnormalities through release of excessive free fatty acids from adipose tissue. This study investigated the effect of oleanolic acid on Adipo-IR. The results showed that supplement with oleanolic acid (25 mg/kg, once daily, by oral gavage) over 10 weeks attenuated liquid fructose-induced increase in plasma insulin concentration and the homeostasis model assessment of insulin resistance (HOMA-IR) index in rats. Simultaneously, oleanolic acid reversed the increase in the Adipo-IR index and plasma non-esterified fatty acid concentrations during the oral glucose tolerance test assessment. In white adipose tissue, oleanolic acid enhanced mRNA expression of the genes encoding insulin receptor, insulin receptor substrate (IRS)-1 and phosphatidylinositol 3-kinase. At the protein level, oleanolic acid upregulated total IRS-1 expression, suppressed the increased phosphorylated IRS-1 at serine-307, and restored the increased phosphorylated IRS-1 to total IRS-1 ratio. In contrast, phosphorylated Akt to total Akt ratio was increased. Furthermore, oleanolic acid reversed fructose-induced decrease in phosphorylated-Akt/Akt protein to plasma insulin concentration ratio. However, oleanolic acid did not affect IRS-2 mRNA expression. Therefore, these results suggest that oleanolic acid supplement ameliorates fructose-induced Adipo-IR in rats via the IRS-1/phosphatidylinositol 3-kinase/Akt pathway. Our findings may provide new insights into the mechanisms of metabolic actions of oleanolic acid. - Highlights: • Adipose insulin resistance (Adipo-IR) contributes to metabolic abnormalities. • We investigated the effect of oleanolic acid (OA) on adipo-IR in

  12. Drosophila insulin release is triggered by adipose Stunted ligand to brain Methuselah receptor.

    Science.gov (United States)

    Delanoue, Renald; Meschi, Eleonora; Agrawal, Neha; Mauri, Alessandra; Tsatskis, Yonit; McNeill, Helen; Léopold, Pierre

    2016-09-30

    Animals adapt their growth rate and body size to available nutrients by a general modulation of insulin-insulin-like growth factor signaling. In Drosophila, dietary amino acids promote the release in the hemolymph of brain insulin-like peptides (Dilps), which in turn activate systemic organ growth. Dilp secretion by insulin-producing cells involves a relay through unknown cytokines produced by fat cells. Here, we identify Methuselah (Mth) as a secretin-incretin receptor subfamily member required in the insulin-producing cells for proper nutrient coupling. We further show, using genetic and ex vivo organ culture experiments, that the Mth ligand Stunted (Sun) is a circulating insulinotropic peptide produced by fat cells. Therefore, Sun and Mth define a new cross-organ circuitry that modulates physiological insulin levels in response to nutrients. Copyright © 2016, American Association for the Advancement of Science.

  13. Clinical study on insulin receptors of mononuclear cells in diabetes

    Energy Technology Data Exchange (ETDEWEB)

    Dalimunthe, D [Hiroshima Univ. (Japan). School of Medicine

    1980-12-01

    /sup 125/I-insulin binding activity to mononuclear cells was studied in 75 noninsulin-dependent diabetic subjects and 31 normal subjects and the following results were obtained. 1. /sup 125/I-insulin binding is directly proportional to the mononuclear cell concentrations. There is a linear increase of specific /sup 125/I-insulin binding. 2. The binding of /sup 125/I-insulin to mononuclear cells is displaced by the increasing concentration of native insulin. 3. The /sup 125/I-insulin degradation in the incubation medium after incubation of mononuclear cells for 24 hours at 4/sup 0/C was almost 5% in this study. 4. The insulin binding activity in diabetic subjects was lower than that in normal subjects (P < 0.001) without any significant difference in affinity constant. 5. The relationship of binding activity to age of diabetics (r = 0.06, N.S), relative body weitht (r = 0.06, N.S) and duration of diabetes from onset was not significant. 6. In untreated noninsulin-dependent diabetics the insulin binding activity was inversely correlated to fasting blood glucose level (r = 0.78, P < 0.001) and slightly inversely correlated to serum insulin level (r = 0.47, P < 0.01). A slight inverse correlation was also observed in serum triglyceride level (r = 0.53, P < 0.01) and in total cholesterol level (r = 0.29, P < 0.05). 7. No significant difference between the binding activity was observed by grade of diabetic retinopathy. 8. After treatment with diet and/or sulfonylurea, the diabetics exhibited a significant increase in insulin binding activity (P < 0.005) but no significant difference in plasma insulin level, body weight and plasma lipid levels was observed.

  14. Coordinate phosphorylation of insulin-receptor kinase and its 175,000-Mr endogenous substrate in rat hepatocytes

    International Nuclear Information System (INIS)

    Okamoto, M.; Karasik, A.; White, M.F.; Kahn, C.R.

    1991-01-01

    To investigate the early events in insulin signal transmission in liver, isolated rat hepatocytes were labeled with 32 P, and proteins phosphorylated in response to insulin were detected by immunoprecipitation with anti-phosphotyrosine and anti-receptor antibodies and analyzed by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis and autoradiography. In these cells, insulin rapidly stimulated tyrosine phosphorylation of the 95,000-Mr beta-subunit of the insulin receptor and a 175,000-Mr phosphoprotein (pp175). Both proteins were precipitated by anti-phosphotyrosine antibody, whereas only the insulin receptor was recognized with anti-insulin-receptor antibody. In the insulin-stimulated state, both pp175 and the receptor beta-subunit were found to be phosphorylated on tyrosine and serine residues. Based on precipitation by the two antibodies, receptor phosphorylation was biphasic with an initial increase in tyrosine phosphorylation followed by a more gradual increase in serine phosphorylation over the first 30 min of stimulation. The time course of phosphorylation of pp175 was rapid and paralleled that of the beta-subunit of the insulin receptor. The pp175 was clearly distinguished from the insulin receptor, because it was detected only when boiling SDS was used to extract cellular phosphoproteins, whereas the insulin receptor was extracted with either Triton X-100 or SDS. In addition, the tryptic peptide maps of the two proteins were distinct. The dose-response curve for insulin stimulation was shifted slightly to the left of the insulin receptor, suggesting some signal amplification at this step. These data suggest that pp175 is a major endogenous substrate of the insulin receptor in liver and may be a cytoskeletal-associated protein

  15. Molecular mechanism of insulin resistance

    Indian Academy of Sciences (India)

    Free fatty acids are known to play a key role in promoting loss of insulin sensitivity, thereby causing insulin resistance and type 2 diabetes. However, the underlying mechanism involved is still unclear. In searching for the cause of the mechanism, it has been found that palmitate inhibits insulin receptor (IR) gene expression, ...

  16. Insulin and IGF receptors are developmentally regulated in the chick embry eye lens

    International Nuclear Information System (INIS)

    Bassas, L.; Zelenka, P.S.; Serrano, J.; de Pablo, F.

    1987-01-01

    The authors have previously reported that insulin-like growth factor (IGF) receptors appear to predominate over insulin receptors in early stages of embryogenesis in the chick (days 2-3 whole embryo membranes). Overall, [ 125 I]IGF and II binding to specific receptors was maximal when the rate of brain growth is highest. In the present study they used the embryonic chick lens, a well-defined tissue composed of a single type of cell, to analyze whether changes of insulin and IGFI binding are correlated with changes in growth rate and differentiation state of the cells. They show that both insulin receptors and IGF receptors are present in the lens epithelial cells, and that each type is distinctly regulated throughout development. While there is a direct correlation between IFG-binding capability and growth rate of the cells, there is less relation to differentiation status and embryo age. Insulin receptors, by contrast, appear to be mostly related to the differentiated state of cells, decreasing sharply in fibers, irrespective of their developmental age

  17. Receptors for insulin-like growth factors I and II: autoradiographic localization in rat brain and comparison to receptors for insulin

    International Nuclear Information System (INIS)

    Lesniak, M.A.; Hill, J.M.; Kiess, W.; Rojeski, M.; Pert, C.B.; Roth, J.

    1988-01-01

    Receptors for insulin-like growth factor I (IGF-I) in rat brain were visualized using autoradiography with [125I]IGF-I. The binding of the labeled peptide was competed for fully by high concentrations of unlabeled IGF-I. At intermediate concentrations of unlabeled peptide the binding of [125I]IGF-I was competed for by unlabeled IGF-I more effectively than by IGF-II or insulin, which is typical of receptors for IGF-I. Essentially every brain section shows specific binding of IGF-I, and the pattern of binding of IGF-I to its receptors correlated well with the cytoarchitectonic structures. In parallel studies we showed that [125I]IGF-II was bound to tissue sections of rat brain and that the binding was competed for by an excess of unlabeled IGF-II. However, intermediate concentrations of unlabeled peptides gave inconclusive results. To confirm that the binding of [125I]IGF-II was to IGF-II receptors, we showed that antibodies specific for the IGF-II receptor inhibited the binding of labeled IGF-II. Furthermore, the binding of the antibody to regions of the brain section, visualized by the application of [125I]protein-A, gave patterns indistinguishable from those obtained with [125I]IGF-II alone. Again, the binding was very widely distributed throughout the central nervous system, and the patterns of distribution corresponded well to the underlying neural structures. Densitometric analysis of the receptors enabled us to compare the distribution of IGF-I receptors with that of IGF-II receptors as well as retrospectively with that of insulin receptors

  18. 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...

  19. Chromosomal organization of adrenergic receptor genes

    International Nuclear Information System (INIS)

    Yang-Feng, T.L.; Xue, Feiyu; Zhong, Wuwei; Cotecchia, S.; Frielle, T.; Caron, M.G.; Lefkowitz, R.J.; Francke, U.

    1990-01-01

    The adrenergic receptors (ARs) (subtypes α 1 , α 2 , β 1 , and β 2 ) are a prototypic family of guanine nucleotide binding regulatory protein-coupled receptors that mediate the physiological effects of the hormone epinephrine and the neurotransmitter norepinephrine. The authors have previously assigned the genes for β 2 -and α 2 -AR to human chromosomes 5 and 10, respectively. By Southern analysis of somatic cell hybrids and in situ chromosomal hybridization, they have now mapped the α 1 -AR gene to chromosome 5q32→q34, the same position as β 2 -AR, and the β 1 -AR gene to chromosome 10q24→q26, the region where α 2 -AR, is located. In mouse, both α 2 -and β 1 -AR genes were assigned to chromosome 19, and the α 1 -AR locus was localized to chromosome 11. Pulsed field gel electrophoresis has shown that the α 1 -and β 2 -AR genes in humans are within 300 kilobases (kb) and the distance between the α 2 - and β 1 -AR genes is <225 kb. The proximity of these two pairs of AR genes and the sequence similarity that exists among all the ARs strongly suggest that they are evolutionarily related. Moreover, they likely arose from a common ancestral receptor gene and subsequently diverged through gene duplication and chromosomal duplication to perform their distinctive roles in mediation the physiological effects of catecholamines. The AR genes thus provide a paradigm for understanding the evolution of such structurally conserved yet functionally divergent families off receptor molecules

  20. Functional characterization of autophosphorylation sites of the activated insulin receptor-tyrosine kinase

    International Nuclear Information System (INIS)

    Flores-Riveros, J.R.; Lane, M.D.

    1987-01-01

    Insulin receptor, solubilized from 3T3-L1 cellular membranes and then purified, was autophosphorylated with [γ- 32 P]ATP in the absence or presence of insulin. Specific phosphopeptides generated by trypsin digestion of the 32 P-labeled β-subunit were identified and separated by reverse phase HPLC. In the absence of insulin, radioactivity of the phosphopeptides is evenly distributed among four major peaks designated as sites I, II, III and IV, according to their order of elution. This pattern is maintained for at least the first 30 min of autophosphorylation. When the reaction is carried out in the presence of insulin, > 50% of the total 32 P radioactivity is found in site I and the rate of 32 P incorporation into this site is markedly higher than into sites II, III and IV. Maximal activation of tyrosine kinase activity, as estimated by substrate phosphorylation, is coincident with the nearly complete phosphorylation of site I. Delayed activation of previously autophosphorylated receptor by insulin, but not by EGF or IGF-I, produced a similar pattern where phosphorylated site I predominates. These observations indicate that one major insulin-regulated autophosphorylation site in the β-subunit is responsible for activation of the insulin receptor tyrosine kinase. The isolation of this phosphopeptide on a preparative scale and its characterization are now in progress

  1. Differential Role of Insulin/IGF-1 Receptor Signaling in Muscle Growth and Glucose Homeostasis

    Directory of Open Access Journals (Sweden)

    Brian T. O’Neill

    2015-05-01

    Full Text Available Insulin and insulin-like growth factor 1 (IGF-1 are major regulators of muscle protein and glucose homeostasis. To determine how these pathways interact, we generated mice with muscle-specific knockout of IGF-1 receptor (IGF1R and insulin receptor (IR. These MIGIRKO mice showed >60% decrease in muscle mass. Despite a complete lack of insulin/IGF-1 signaling in muscle, MIGIRKO mice displayed normal glucose and insulin tolerance. Indeed, MIGIRKO mice showed fasting hypoglycemia and increased basal glucose uptake. This was secondary to decreased TBC1D1 resulting in increased Glut4 and Glut1 membrane localization. Interestingly, overexpression of a dominant-negative IGF1R in muscle induced glucose intolerance in MIGIRKO animals. Thus, loss of insulin/IGF-1 signaling impairs muscle growth, but not whole-body glucose tolerance due to increased membrane localization of glucose transporters. Nonetheless, presence of a dominant-negative receptor, even in the absence of functional IR/IGF1R, induces glucose intolerance, indicating that interactions between these receptors and other proteins in muscle can impair glucose homeostasis.

  2. Adiponectin, Leptin, and Leptin Receptor in Obese Patients with Type 2 Diabetes Treated with Insulin Detemir

    Directory of Open Access Journals (Sweden)

    Paweł Olczyk

    2017-07-01

    Full Text Available The aim of the present study is to quantitatively assess the expression of selected regulatory molecules, such as leptin, leptin receptor, and adiponectin in the blood of obese patients with type 2 diabetes both before treatment and after six months of pharmacological therapy with the long-lasting insulin analogue, insulin detemir. A significant decrease in the analysed regulatory molecules, i.e., leptin receptor and adiponectin, was found in blood plasma of the patients with untreated type 2 diabetes. These changes were accompanied by an increase in plasma leptin concentrations. Insulin treatment resulted in the normalization of plasma leptin receptor and adiponectin concentrations. The circulating leptin level did not change following anti-diabetic therapy with insulin detemir. Gender was a significant factor modifying the circulating level of all the analysed regulatory active compounds. Bioinformatic analysis was performed using Matlab with the Signal Processing Toolbox. The conducted discriminant analysis revealed that the leptin receptor, Δw(19, and adiponectin, Δw(21, were the parameters undergoing the most significant quantitative changes during the six-month therapy with insulin detemir. The conducted examinations indicated the contribution of adipocytokines—the biologically-active mediators of systemic metabolism, such as leptin and adiponectin in the pathomechanism of disorders being the basis for obesity which leads to development of insulin resistance, which, in turn, results in the occurrence of type 2 diabetes.

  3. Effect of hypothermia on the insulin-receptor interaction in skeletal muscle plasma membranes

    International Nuclear Information System (INIS)

    Torlinska T, Mackowiak P.; Nogowski L, Kozlik J.

    1996-01-01

    The aim of the study was to investigate the effect of hypothermia on (125-I)-insulin binding to rat skeletal muscle membranes and to determine whether the decrease in blood insulin concentration could be related to changes in the number or in the affinity of insulin receptor sites according to the down-regulation theory. Rat skeletal muscle membranes were prepared from control, normothermic rats (Tr = 35.6 ± 0.3 degree C) and hypothermic rats (Tr = 26.0 ± 0.5 deg C) and purified according to Havrankowa. In order to determine the kinetic parameters of the hormone-receptor interaction the data from the competition binding studies were analysed by the method of Scatchard using the LIGAND Pc.v.3.1. computer program of Munson and Rodbard. We have shown that under hypothermic conditions insulin receptors number is significantly increased in specific hindlimb skeletal muscles but the changes take place mainly in the low affinity receptors class. The phenomenon probably results from the lack of spare high affinity insulin receptors in skeletal muscle as shown recently by Camps et al. (author). 36 refs., 3 figs, 2 tabs

  4. Insulin-like growth factor type-1 receptor down-regulation associated with dwarfism in Holstein calves.

    Science.gov (United States)

    Blum, J W; Elsasser, T H; Greger, D L; Wittenberg, S; de Vries, F; Distl, O

    2007-10-01

    Perturbations in endocrine functions can impact normal growth. Endocrine traits were studied in three dwarf calves exhibiting retarded but proportionate growth and four phenotypically normal half-siblings, sired by the same bull, and four unrelated control calves. Plasma 3,5,3'-triiodothyronine and thyroxine concentrations in dwarfs and half-siblings were in the physiological range and responded normally to injected thyroid-releasing hormone. Plasma glucagon concentrations were different (dwarfs, controls>half-siblings; Pcontrols, Pcontrols, P=0.08). Responses of GH to xylazine and to a GH-releasing-factor analogue were similar in dwarfs and half-siblings. Relative gene expression of IGF-1, IGF-2, GH receptor (GHR), insulin receptor, IGF-1 type-1 and -2 receptors (IGF-1R, IGF-2R), and IGF binding proteins were measured in liver and anconeus muscle. GHR mRNA levels were different in liver (dwarfsdwarfism in studied calves.

  5. Chemokine-like receptor 1 deficiency does not affect the development of insulin resistance and nonalcoholic fatty liver disease in mice.

    Directory of Open Access Journals (Sweden)

    Nanda Gruben

    Full Text Available The adipokine chemerin and its receptor, chemokine-like receptor 1 (Cmklr1, are associated with insulin resistance and nonalcoholic fatty liver disease (NAFLD, which covers a broad spectrum of liver diseases, ranging from simple steatosis to nonalcoholic steatohepatitis (NASH. It is possible that chemerin and/or Cmklr1 exert their effects on these disorders through inflammation, but so far the data have been controversial. To gain further insight into this matter, we studied the effect of whole-body Cmklr1 deficiency on insulin resistance and NAFLD. In view of the primary role of macrophages in hepatic inflammation, we also transplanted bone marrow from Cmklr1 knock-out (Cmklr1-/- mice and wild type (WT mice into low-density lipoprotein receptor knock-out (Ldlr-/- mice, a mouse model for NASH. All mice were fed a high fat, high cholesterol diet containing 21% fat from milk butter and 0.2% cholesterol for 12 weeks. Insulin resistance was assessed by an oral glucose tolerance test, an insulin tolerance test, and by measurement of plasma glucose and insulin levels. Liver pathology was determined by measuring hepatic inflammation, fibrosis, lipid accumulation and the NAFLD activity score (NAS. Whole-body Cmklr1 deficiency did not affect body weight gain or food intake. In addition, we observed no differences between WT and Cmklr1-/- mice for hepatic inflammatory and fibrotic gene expression, immune cell infiltration, lipid accumulation or NAS. In line with this, we detected no differences in insulin resistance. In concordance with whole-body Cmklr1 deficiency, the absence of Cmklr1 in bone marrow-derived cells in Ldlr-/- mice did not affect their insulin resistance or liver pathology. Our results indicate that Cmklr1 is not involved in the pathogenesis of insulin resistance or NAFLD. Thus, we recommend that the associations reported between Cmklr1 and insulin resistance or NAFLD should be interpreted with caution.

  6. 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.

  7. Theoretical and Computational Studies of Peptides and Receptors of the Insulin Family

    Directory of Open Access Journals (Sweden)

    Harish Vashisth

    2015-02-01

    Full Text Available Synergistic interactions among peptides and receptors of the insulin family are required for glucose homeostasis, normal cellular growth and development, proliferation, differentiation and other metabolic processes. The peptides of the insulin family are disulfide-linked single or dual-chain proteins, while receptors are ligand-activated transmembrane glycoproteins of the receptor tyrosine kinase (RTK superfamily. Binding of ligands to the extracellular domains of receptors is known to initiate signaling via activation of intracellular kinase domains. While the structure of insulin has been known since 1969, recent decades have seen remarkable progress on the structural biology of apo and liganded receptor fragments. Here, we review how this useful structural information (on ligands and receptors has enabled large-scale atomically-resolved simulations to elucidate the conformational dynamics of these biomolecules. Particularly, applications of molecular dynamics (MD and Monte Carlo (MC simulation methods are discussed in various contexts, including studies of isolated ligands, apo-receptors, ligand/receptor complexes and intracellular kinase domains. The review concludes with a brief overview and future outlook for modeling and computational studies in this family of proteins.

  8. Context-dependent regulation of feeding behaviour by the insulin receptor, DAF-2, in Caenorhabditis elegans.

    Science.gov (United States)

    Dillon, James; Holden-Dye, Lindy; O'Connor, Vincent; Hopper, Neil A

    2016-06-01

    Insulin signalling plays a significant role in both developmental programmes and pathways modulating the neuronal signalling that controls adult behaviour. Here, we have investigated insulin signalling in food-associated behaviour in adult C. elegans by scoring locomotion and feeding on and off bacteria, the worm's food. This analysis used mutants (daf-2, daf-18) of the insulin signalling pathway, and we provide evidence for an acute role for insulin signalling in the adult nervous system distinct from its impact on developmental programmes. Insulin receptor daf-2 mutants move slower than wild type both on and off food and showed impaired locomotory responses to food deprivation. This latter behaviour is manifest as a failure to instigate dispersal following prolonged food deprivation and suggests a role for insulin signalling in this adaptive response. Insulin receptor daf-2 mutants are also deficient in pharyngeal pumping on food and off food. Pharmacological analysis showed the pharynx of daf-2 is selectively compromised in its response to 5-HT compared to the excitatory neuropeptide FLP-17. By comparing the adaptive pharyngeal behaviour in intact worms and isolated pharyngeal preparations, we determined that an insulin-dependent signal extrinsic to the pharyngeal system is involved in feeding adaptation. Hence, we suggest that reactive insulin signalling modulates both locomotory foraging and pharyngeal pumping as the animal adapts to the absence of food. We discuss this in the context of insulin signalling directing a shift in the sensitivity of neurotransmitter systems to regulate the worm's response to changes in food availability in the environment.

  9. Gene expression of tumour necrosis factor and insulin signalling-related factors in subcutaneous adipose tissue during the dry period and in early lactation in dairy cows.

    Science.gov (United States)

    Sadri, H; Bruckmaier, R M; Rahmani, H R; Ghorbani, G R; Morel, I; van Dorland, H A

    2010-10-01

    Gene expression of adipose factors, which may be part of the mechanisms that underlie insulin sensitivity, were studied in dairy cows around parturition. Subcutaneous fat biopsies and blood samples were taken from 27 dairy cows in week 8 antepartum (a.p.), on day 1 postpartum (p.p.) and in week 5 p.p. In the adipose tissue samples, mRNA was quantified by real-time reverse transcription polymerase chain reaction for tumour necrosis factor alpha (TNFα), insulin-independent glucose transporter (GLUT1), insulin-responsive glucose transporter (GLUT4), insulin receptor, insulin receptor substrate 1 (IRS1), insulin receptor substrate 2 (IRS2), regulatory subunit of phosphatidylinositol-3 kinase (p85) and catalytic subunit of phosphatidylinositol-3 kinase. Blood plasma was assayed for concentrations of glucose, β-hydroxybutyric acid, non-esterified fatty acids (NEFA) and insulin. Plasma parameters followed a pattern typically observed in dairy cows. Gene expression changes were observed, but there were no changes in TNFα concentrations, which may indicate its local involvement in catabolic adaptation of adipose tissue. Changes in GLUT4 and GLUT1 mRNA abundance may reflect their involvement in reduced insulin sensitivity and in sparing glucose for milk synthesis in early lactation. Unchanged gene expression of IRS1, IRS2 and p85 over time may imply a lack of their involvement in terms of insulin sensitivity dynamics. Alternatively, it may indicate that post-transcriptional modifications of these factors came into play and may have concealed an involvement. © 2010 Blackwell Verlag GmbH.

  10. Label-Free Proteomic Identification of Endogenous, Insulin-Stimulated Interaction Partners of Insulin Receptor Substrate-1

    Science.gov (United States)

    Geetha, Thangiah; Langlais, Paul; Luo, Moulun; Mapes, Rebekka; Lefort, Natalie; Chen, Shu-Chuan; Mandarino, Lawrence J.; Yi, Zhengping

    2011-03-01

    Protein-protein interactions are key to most cellular processes. Tandem mass spectrometry (MS/MS)-based proteomics combined with co-immunoprecipitation (CO-IP) has emerged as a powerful approach for studying protein complexes. However, a majority of systematic proteomics studies on protein-protein interactions involve the use of protein overexpression and/or epitope-tagged bait proteins, which might affect binding stoichiometry and lead to higher false positives. Here, we report an application of a straightforward, label-free CO-IP-MS/MS method, without the use of protein overexpression or protein tags, to the investigation of changes in the abundance of endogenous proteins associated with a bait protein, which is in this case insulin receptor substrate-1 (IRS-1), under basal and insulin stimulated conditions. IRS-1 plays a central role in the insulin signaling cascade. Defects in the protein-protein interactions involving IRS-1 may lead to the development of insulin resistance and type 2 diabetes. HPLC-ESI-MS/MS analyses identified eleven novel endogenous insulin-stimulated IRS-1 interaction partners in L6 myotubes reproducibly, including proteins play an important role in protein dephosphorylation [protein phosphatase 1 regulatory subunit 12A, (PPP1R12A)], muscle contraction and actin cytoskeleton rearrangement, endoplasmic reticulum stress, and protein folding, as well as protein synthesis. This novel application of label-free CO-IP-MS/MS quantification to assess endogenous interaction partners of a specific protein will prove useful for understanding how various cell stimuli regulate insulin signal transduction.

  11. Intrahepatic detection of insulin receptor substrate 2 in chronic hepatitis c patients

    International Nuclear Information System (INIS)

    Ahmed, N.; Rashid, A.; Bashir, Q.; Majeed, A.

    2017-01-01

    To detect hepatic insulin receptor substrate 2 in chronic hepatitis C patients. Study Design: Comparative study. Place and Duration of Study: Center for research in experimental and applied medicine (CREAM), Department of Biochemistry and Molecular Biology, Army Medical College and Holy Family Hospital Rawalpindi, from Dec 2011 to Nov 2012. Diagnosed patients of chronic hepatitis C were included in the study. Known cases of diabetes mellitus, patients with pancreatic disease and liver pathology other than hepatitis C were excluded from the study. Material and Methods: Twenty seropositive non diabetic HCV infected patients and 10 control subjects were recruited. Liver biopsy specimen was obtained from seropositive HCV patients while blood samples were obtained from controls as biopsy sample was not possible from normal controls. Both types of speciens were studied for detection of insulin receptor substrate 2 (IRS-2). Results: No alteration in the content of insulin receptor substrate 2 in both seropositive patients and control samples were detected. Conclusion: Hepatitis C virus has no effect on insulin receptor substrate 2 content thus indicating absence of hepatic insulin resistance in patients with HCV infection. (author)

  12. Roles of oxidative stress, adiponectin, and nuclear hormone receptors in obesity-associated insulin resistance and cardiovascular risk.

    Science.gov (United States)

    Matsuda, Morihiro; Shimomura, Iichiro

    2014-08-01

    Obesity leads to the development of type 2 diabetes mellitus, which is a strong risk factor for cardiovascular disease. A better understanding of the molecular basis of obesity will lead to the establishment of effective prevention strategies for cardiovascular diseases. Adipocytes have been shown to generate a variety of endocrine factors termed adipokines/adipocytokines. Obesity-associated changes to these adipocytokines contribute to the development of cardiovascular diseases. Adiponectin, which is one of the most well-characterized adipocytokines, is produced exclusively by adipocytes and exerts insulin-sensitizing and anti-atherogenic effects. Obese subjects have lower levels of circulating adiponectin, and this is recognized as one of the factors involved in obesity-induced insulin resistance and atherosclerosis. Another pathophysiological feature of obesity may involve the low-grade chronic inflammation in adipose tissue. This inflammatory process increases oxidative stress in adipose tissue, which may affect remote organs, leading to the development of diabetes, hypertension, and atherosclerosis. Nuclear hormone receptors (NRs) regulate the transcription of the target genes in response to binding with their ligands, which include metabolic and nutritional substrates. Among the various NRs, peroxisome proliferator-activated receptor γ promotes the transcription of adiponectin and antioxidative enzymes, whereas mineralocorticoid receptor mediates the effects of aldosterone and glucocorticoid to induce oxidative stress in adipocytes. It is hypothesized that both play crucial roles in the pathophysiology of obesity-associated insulin resistance and cardiovascular diseases. Thus, reduced adiponectin and increased oxidative stress play pathological roles in obesity-associated insulin resistance to increase the cardiovascular disease risk, and various NRs may be involved in this pathogenesis.

  13. Hepatic changes in metabolic gene expression in old ghrelin and ghrelin receptor knockout mice

    Science.gov (United States)

    Ghrelin knockout (GKO) and ghrelin receptor (growth hormone secretagogue receptor) knockout (GHSRKO) mice exhibit enhanced insulin sensitivity, but the mechanism is unclear. Insulin sensitivity declines with age and is inversely associated with accumulation of lipid in liver, a key glucoregulatory ...

  14. Ultrastructural evidence for the accumulation of insulin in nuclei of intact 3T3-L1 adipocytes by an insulin-receptor mediated process

    International Nuclear Information System (INIS)

    Smith, R.M.; Jarett, L.

    1987-01-01

    Monomeric ferritin-labeled insulin (F/sub m/-Ins), a biologically active, electron-dense marker of occupied insulin receptors, was used to characterize the internalization of insulin in 3T3-L1 adipocytes. F/sub m/-Ins bound specifically to insulin receptors and was internalized in a time- and temperature-dependent manner. In the nucleus, several F/sub m/-Ins particles usually were found in the same general location-near nuclear pores, associated with the periphery of the condensed chromatin. Addition of a 250-fold excess of unlabeled insulin or incubation at 15 0 C reduced the number of F/sub m/-Ins particles found in nuclei after 90 min by 99% or 92%, respectively. Nuclear accumulation of unlabeled ferritin was only 2% of that found with F/sub m/-Ins after 90 min at 37 0 C. Biochemical experiments utilizing 125 I-labeled insulin and subcellular fractionation indicated that intact 3T3-L1 adipocytes internalized insulin rapidly and that ≅ 3% of the internalized ligand accumulated in nuclei after 1 hr. These data provide biochemical and high-resolution ultrastructural evidence that 3T3-L1 adipocytes accumulate potentially significant amounts of insulin in nuclei by an insulin receptor-mediated process. The transport of insulin or the insulin-receptor complex to nuclei in this cell or in others may be directly involved in the long-term biological effects of insulin - in particular, in the control of DNA and RNA synthesis

  15. Relationships between endothelin and insulin receptor of red blood cell and insulin resistance in patients with hypertension

    International Nuclear Information System (INIS)

    Tong Qian; Zheng Yang; Xu Hui

    2004-01-01

    Objective: To find the relationships between endothelin (ET) and insulin resistance (IR) and insulin receptor (INSR) in patients with essential hypertension. Methods: Forty patients including 20 cases of essential hypertension disease (EHD) and 20 health persons were divided into experimental group and control group. Blood glucose, serum insulin, ET and the number of erythrocyte INSR in all patients during fasting condition were detected by radioimmunoassay and radiometric analysis. Results: Both insulin sensitivity index (ISI) and the number of INSR in EHD group were much less than that of control group, on the contrary, ET level of EHD group was significantly higher than that of control group (P<0.05). Statistical analysis demonstrated a negative correlation between ET and ISI and INSR number existed in EHD group. Conclusion: IR is a common phenomenon in patient with EHD and possibly due to decrease of INSR number. The ET levels are higher in patients with EHD than that in health people and correlate with INSR, and the change of INSR number is the possible mediator for their relationship

  16. Insulin and IGF1 Receptors Are Essential for XX and XY Gonadal Differentiation and Adrenal Development in Mice

    Science.gov (United States)

    Romero, Yannick; Conne, Béatrice; Truong, Vy; Papaioannou, Marilena D.; Schaad, Olivier; Docquier, Mylène; Herrera, Pedro Luis; Wilhelm, Dagmar; Nef, Serge

    2013-01-01

    Mouse sex determination provides an attractive model to study how regulatory genetic networks and signaling pathways control cell specification and cell fate decisions. This study characterizes in detail the essential role played by the insulin receptor (INSR) and the IGF type I receptor (IGF1R) in adrenogenital development and primary sex determination. Constitutive ablation of insulin/IGF signaling pathway led to reduced proliferation rate of somatic progenitor cells in both XX and XY gonads prior to sex determination together with the downregulation of hundreds of genes associated with the adrenal, testicular, and ovarian genetic programs. These findings indicate that prior to sex determination somatic progenitors in Insr;Igf1r mutant gonads are not lineage primed and thus incapable of upregulating/repressing the male and female genetic programs required for cell fate restriction. In consequence, embryos lacking functional insulin/IGF signaling exhibit (i) complete agenesis of the adrenal cortex, (ii) embryonic XY gonadal sex reversal, with a delay of Sry upregulation and the subsequent failure of the testicular genetic program, and (iii) a delay in ovarian differentiation so that Insr;Igf1r mutant gonads, irrespective of genetic sex, remained in an extended undifferentiated state, before the ovarian differentiation program ultimately is initiated at around E16.5. PMID:23300479

  17. Delayed puberty but normal fertility in mice with selective deletion of insulin receptors from Kiss1 cells.

    Science.gov (United States)

    Qiu, Xiaoliang; Dowling, Abigail R; Marino, Joseph S; Faulkner, Latrice D; Bryant, Benjamin; Brüning, Jens C; Elias, Carol F; Hill, Jennifer W

    2013-03-01

    Pubertal onset only occurs in a favorable, anabolic hormonal environment. The neuropeptide kisspeptin, encoded by the Kiss1 gene, modifies GnRH neuronal activity to initiate puberty and maintain fertility, but the factors that regulate Kiss1 neurons and permit pubertal maturation remain to be clarified. The anabolic factor insulin may signal nutritional status to these neurons. To determine whether insulin sensing plays an important role in Kiss1 neuron function, we generated mice lacking insulin receptors in Kiss1 neurons (IR(ΔKiss) mice). IR(ΔKiss) females showed a delay in vaginal opening and in first estrus, whereas IR(ΔKiss) males also exhibited late sexual maturation. Correspondingly, LH levels in IR(ΔKiss) mice were reduced in early puberty in both sexes. Adult reproductive capacity, body weight, fat composition, food intake, and glucose regulation were comparable between the 2 groups. These data suggest that impaired insulin sensing by Kiss1 neurons delays the initiation of puberty but does not affect adult fertility. These studies provide insight into the mechanisms regulating pubertal timing in anabolic states.

  18. One week treatment with the IL-1 receptor antagonist anakinra leads to a sustained improvement in insulin sensitivity in insulin resistant patients with type 1 diabetes mellitus

    NARCIS (Netherlands)

    Asseldonk, van E.J.P.; Poppel, van P.C.M.; Ballak, D.B.; Stienstra, Rinke; Netea, M.G.; Tack, C.J.

    2015-01-01

    Inflammation associated with obesity is involved in the development of insulin resistance. We hypothesized that anti-inflammatory treatment with the Interleukin-1 receptor antagonist anakinra would improve insulin sensitivity.In an open label proof-of-concept study, we included overweight

  19. An insulin receptor mutant (Asp707 → Ala), involved in leprechaunism, is processed and transported to the cell surface but unable to bind insulin

    NARCIS (Netherlands)

    L.M. 't Hart (Leen); D. Lindhout (Dick); G.C.M. van der Zon (Gerard); H. Kayserilli (Hülya); M.Y. Apak (Memnune); W.J. Kleijer (Wim); E.R. van der Vorm (Eric); J.A. Maassen (Johannes)

    1996-01-01

    textabstractWe have identified a homozygous mutation near the carboxyl terminus of the insulin receptor (IR) α subunit from a leprechaun patient, changing Asp707 into Ala. Fibroblasts from this patient had no high affinity insulin binding sites. To examine the effect of the mutation on IR

  20. Adiponectin release and insulin receptor targeting share trans-Golgi-dependent endosomal trafficking routes

    Directory of Open Access Journals (Sweden)

    Maria Rödiger

    2018-02-01

    Full Text Available Objective: Intracellular vesicle trafficking maintains cellular structures and functions. The assembly of cargo-laden vesicles at the trans-Golgi network is initiated by the ARF family of small GTPases. Here, we demonstrate the role of the trans-Golgi localized monomeric GTPase ARFRP1 in endosomal-mediated vesicle trafficking of mature adipocytes. Methods: Control (Arfrp1flox/flox and inducible fat-specific Arfrp1 knockout (Arfrp1iAT−/− mice were metabolically characterized. In vitro experiments on mature 3T3-L1 cells and primary mouse adipocytes were conducted to validate the impact of ARFRP1 on localization of adiponectin and the insulin receptor. Finally, secretion and transferrin-based uptake and recycling assays were performed with HeLa and HeLa M-C1 cells. Results: We identified the ARFRP1-based sorting machinery to be involved in vesicle trafficking relying on the endosomal compartment for cell surface delivery. Secretion of adiponectin from fat depots was selectively reduced in Arfrp1iAT−/− mice, and Arfrp1-depleted 3T3-L1 adipocytes revealed an accumulation of adiponectin in Rab11-positive endosomes. Plasma adiponectin deficiency of Arfrp1iAT−/− mice resulted in deteriorated hepatic insulin sensitivity, increased gluconeogenesis and elevated fasting blood glucose levels. Additionally, the insulin receptor, undergoing endocytic recycling after ligand binding, was less abundant at the plasma membrane of adipocytes lacking Arfrp1. This had detrimental effects on adipose insulin signaling, followed by insufficient suppression of basal lipolytic activity and impaired adipose tissue expansion. Conclusions: Our findings suggest that adiponectin secretion and insulin receptor surface targeting utilize the same post-Golgi trafficking pathways that are essential for an appropriate systemic insulin sensitivity and glucose homeostasis. Keywords: Adiponectin, ARFRP1, Exocytosis, Insulin receptor, trans-Golgi

  1. Regulation of ENaC in mice lacking renal insulin receptors in the collecting duct

    Science.gov (United States)

    Pavlov, Tengis S.; Ilatovskaya, Daria V.; Levchenko, Vladislav; Li, Lijun; Ecelbarger, Carolyn M.; Staruschenko, Alexander

    2013-01-01

    The epithelial sodium channel (ENaC) is one of the central effectors involved in regulation of salt and water homeostasis in the kidney. To study mechanisms of ENaC regulation, we generated knockout mice lacking the insulin receptor (InsR KO) specifically in the collecting duct principal cells. Single-channel analysis in freshly isolated split-open tubules demonstrated that the InsR-KO mice have significantly lower ENaC activity compared to their wild-type (C57BL/6J) littermates when animals were fed either normal or sodium-deficient diets. Immunohistochemical and Western blot assays demonstrated no significant changes in expression of ENaC subunits in InsR-KO mice compared to wild-type littermates. Insulin treatment caused greater ENaC activity in split-open tubules isolated from wild-type mice but did not have this effect in the InsR-KO mice. Thus, these results suggest that insulin increases ENaC activity via its own receptor affecting the channel open probability. To further determine the mechanism of the action of insulin on ENaC, we used mouse mpkCCDc14 principal cells. Insulin significantly augmented amiloride-sensitive transepithelial flux in these cells. Pretreatment of the mpkCCDc14 cells with phosphatidylinositol 3-kinase (LY294002; 10 μM) or mTOR (PP242; 100 nM) inhibitors precluded this effect. This study provides new information about the importance of insulin receptors expressed in collecting duct principal cells for ENaC activity.—Pavlov, T. S., Ilatovskaya, D. V., Levchenko, V., Li, L., Ecelbarger, C. M., Staruschenko, A. Regulation of ENaC in mice lacking renal insulin receptors in the collecting duct. PMID:23558339

  2. Insulin and Insulin-like Growth Factor II Differentially Regulate Endocytic Sorting and Stability of Insulin Receptor Isoform A

    Czech Academy of Sciences Publication Activity Database

    Morcavallo, A.; Genua, M.; Palummo, A.; Kletvíková, Emília; Jiráček, Jiří; Brzozowski, A. M.; Lozzo, R. V.; Belfiore, A.; Morrione, A.

    2012-01-01

    Roč. 287, č. 14 (2012), s. 11422-11436 ISSN 0021-9258 Institutional research plan: CEZ:AV0Z40550506 Keywords : insulin * IGF -II * mitogenic response * IR-A Subject RIV: CE - Biochemistry Impact factor: 4.651, year: 2012

  3. PPAR-γ activation increases insulin secretion through the up-regulation of the free fatty acid receptor GPR40 in pancreatic β-cells.

    Directory of Open Access Journals (Sweden)

    Hyo-Sup Kim

    Full Text Available BACKGROUND: It has been reported that peroxisome proliferator-activated receptor (PPAR-γ and their synthetic ligands have direct effects on pancreatic β-cells. We investigated whether PPAR-γ activation stimulates insulin secretion through the up-regulation of GPR40 in pancreatic β-cells. METHODS: Rat insulinoma INS-1 cells and primary rat islets were treated with rosiglitazone (RGZ and/or adenoviral PPAR-γ overexpression. OLETF rats were treated with RGZ. RESULTS: PPAR-γ activation with RGZ and/or adenoviral PPAR-γ overexpression increased free fatty acid (FFA receptor GPR40 expression, and increased insulin secretion and intracellular calcium mobilization, and was blocked by the PLC inhibitors, GPR40 RNA interference, and GLUT2 RNA interference. As a downstream signaling pathway of intracellular calcium mobilization, the phosphorylated levels of CaMKII and CREB, and the downstream IRS-2 and phospho-Akt were significantly increased. Despite of insulin receptor RNA interference, the levels of IRS-2 and phospho-Akt was still maintained with PPAR-γ activation. In addition, the β-cell specific gene expression, including Pdx-1 and FoxA2, increased in a GPR40- and GLUT2-dependent manner. The levels of GPR40, phosphorylated CaMKII and CREB, and β-cell specific genes induced by RGZ were blocked by GW9662, a PPAR-γ antagonist. Finally, PPAR-γ activation up-regulated β-cell gene expressions through FoxO1 nuclear exclusion, independent of the insulin signaling pathway. Based on immunohistochemical staining, the GLUT2, IRS-2, Pdx-1, and GPR40 were more strongly expressed in islets from RGZ-treated OLETF rats compared to control islets. CONCLUSION: These observations suggest that PPAR-γ activation with RGZ and/or adenoviral overexpression increased intracellular calcium mobilization, insulin secretion, and β-cell gene expression through GPR40 and GLUT2 gene up-regulation.

  4. Pharmacodynamic/Pharmacogenomic Modeling of Insulin Resistance Genes in Rat Muscle After Methylprednisolone Treatment: Exploring Regulatory Signaling Cascades

    Directory of Open Access Journals (Sweden)

    Zhenling Yao

    2008-01-01

    Full Text Available Corticosteroids (CS effects on insulin resistance related genes in rat skeletal muscle were studied. In our acute study, adrenalectomized (ADX rats were given single doses of 50 mg/kg methylprednisolone (MPL intravenously. In our chronic study, ADX rats were implanted with Alzet mini-pumps giving zero-order release rates of 0.3 mg/kg/h MPL and sacrificed at various times up to 7 days. Total RNA was extracted from gastrocnemius muscles and hybridized to Affymetrix GeneChips. Data mining and literature searches identified 6 insulin resistance related genes which exhibited complex regulatory pathways. Insulin receptor substrate-1 (IRS-1, uncoupling protein 3 (UCP3, pyruvate dehydrogenase kinase isoenzyme 4 (PDK4, fatty acid translocase (FAT and glycerol-3-phosphate acyltransferase (GPAT dynamic profiles were modeled with mutual effects by calculated nuclear drug-receptor complex (DR(N and transcription factors. The oscillatory feature of endothelin-1 (ET-1 expression was depicted by a negative feedback loop. These integrated models provide test- able quantitative hypotheses for these regulatory cascades.

  5. Heparanase augments insulin receptor signaling in breast carcinoma

    Science.gov (United States)

    Goldberg, Rachel; Sonnenblick, Amir; Hermano, Esther; Hamburger, Tamar; Meirovitz, Amichay; Peretz, Tamar; Elkin, Michael

    2017-01-01

    Recently, growing interest in the potential link between metabolic disorders (i.e., diabetes, obesity, metabolic syndrome) and breast cancer has mounted, including studies which indicate that diabetic/hyperinsulinemic women have a significantly higher risk of bearing breast tumors that are more aggressive and associated with higher death rates. Insulin signaling is regarded as a major contributor to this phenomenon; much less is known about the role of heparan sulfate-degrading enzyme heparanase in the link between metabolic disorders and cancer. In the present study we analyzed clinical samples of breast carcinoma derived from diabetic/non-diabetic patients, and investigated effects of heparanase on insulin signaling in breast carcinoma cell lines, as well as insulin-driven growth of breast tumor cells. We demonstrate that heparanase activity leads to enhanced insulin signaling and activation of downstream tumor-promoting pathways in breast carcinoma cells. In agreement, heparanase enhances insulin-induced proliferation of breast tumor cells in vitro. Moreover, analyzing clinical data from diabetic breast carcinoma patients, we found that concurrent presence of both diabetic state and heparanase in tumor tissue (as opposed to either condition alone) was associated with more aggressive phenotype of breast tumors in the patient cohort analyzed in our study (two-sided Fisher's exact test; p=0.04). Our findings highlight the emerging role of heparanase in powering effect of hyperinsulinemic state on breast tumorigenesis and imply that heparanase targeting, which is now under intensive development/clinical testing, could be particularly efficient in a growing fraction of breast carcinoma patients suffering from metabolic disorders. PMID:28038446

  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. Therapeutic actions of an insulin receptor activator and a novel peroxisome proliferator-activated receptor gamma agonist in the spontaneously hypertensive obese rat model of metabolic syndrome X.

    Science.gov (United States)

    Velliquette, Rodney A; Friedman, Jacob E; Shao, J; Zhang, Bei B; Ernsberger, Paul

    2005-07-01

    Insulin resistance clusters with hyperlipidemia, impaired glucose tolerance, and hypertension as metabolic syndrome X. We tested a low molecular weight insulin receptor activator, demethylasterriquinone B-1 (DMAQ-B1), and a novel indole peroxisome proliferator-activated receptor gamma agonist, 2-(2-(4-phenoxy-2-propylphenoxy)ethyl)indole-5-acetic acid (PPEIA), in spontaneously hypertensive obese rats (SHROB), a genetic model of syndrome X. Agents were given orally for 19 days. SHROB showed fasting normoglycemia but impaired glucose tolerance after an oral load, as shown by increased glucose area under the curve (AUC) [20,700 mg x min/ml versus 8100 in lean spontaneously hypertensive rats (SHR)]. Insulin resistance was indicated by 20-fold excess fasting insulin and increased insulin AUC (6300 ng x min/ml versus 990 in SHR). DMAQ-B1 did not affect glucose tolerance (glucose AUC = 21,300) but reduced fasting insulin 2-fold and insulin AUC (insulin AUC = 4300). PPEIA normalized glucose tolerance (glucose AUC = 9100) and reduced insulin AUC (to 3180) without affecting fasting insulin. PPEIA also increased food intake, fat mass, and body weight gain (81 +/- 12 versus 45 +/- 8 g in untreated controls), whereas DMAQ-B1 had no effect on body weight but reduced subscapular fat mass. PPEIA but not DMAQ-B1 reduced blood pressure. In skeletal muscle, insulin-stimulated phosphorylation of the insulin receptor and insulin receptor substrate protein 1-associated phosphatidylinositol 3-kinase activity were decreased by 40 to 55% in SHROB relative to lean SHR. PPEIA, but not DMAQ-B1, enhanced both insulin actions. SHROB also showed severe hypertriglyceridemia (355 +/- 42 mg/dl versus 65 +/- 3 in SHR) attenuated by both agents (DMAQ-B1, 228 +/- 18; PPEIA, 79 +/- 3). Both these novel antidiabetic agents attenuate insulin resistance and hypertriglyceridemia associated with metabolic syndrome but via distinct mechanisms.

  8. Enhanced muscarinic M1 receptor gene expression in the corpus striatum of streptozotocin-induced diabetic rats

    Directory of Open Access Journals (Sweden)

    Mathew Jobin

    2009-04-01

    Full Text Available Abstract Acetylcholine (ACh, the first neurotransmitter to be identified, regulate the activities of central and peripheral functions through interactions with muscarinic receptors. Changes in muscarinic acetylcholine receptor (mAChR have been implicated in the pathophysiology of many major diseases of the central nervous system (CNS. Previous reports from our laboratory on streptozotocin (STZ induced diabetic rats showed down regulation of muscarinic M1 receptors in the brainstem, hypothalamus, cerebral cortex and pancreatic islets. In this study, we have investigated the changes of acetylcholine esterase (AChE enzyme activity, total muscarinic and muscarinic M1 receptor binding and gene expression in the corpus striatum of STZ – diabetic rats and the insulin treated diabetic rats. The striatum, a neuronal nucleus intimately involved in motor behaviour, is one of the brain regions with the highest acetylcholine content. ACh has complex and clinically important actions in the striatum that are mediated predominantly by muscarinic receptors. We observed that insulin treatment brought back the decreased maximal velocity (Vmax of acetylcholine esterase in the corpus striatum during diabetes to near control state. In diabetic rats there was a decrease in maximal number (Bmax and affinity (Kd of total muscarinic receptors whereas muscarinic M1 receptors were increased with decrease in affinity in diabetic rats. We observed that, in all cases, the binding parameters were reversed to near control by the treatment of diabetic rats with insulin. Real-time PCR experiment confirmed the increase in muscarinic M1 receptor gene expression and a similar reversal with insulin treatment. These results suggest the diabetes-induced changes of the cholinergic activity in the corpus striatum and the regulatory role of insulin on binding parameters and gene expression of total and muscarinic M1 receptors.

  9. Functional labeling of insulin receptor subunits in live cells. Alpha 2 beta 2 species is the major autophosphorylated form

    International Nuclear Information System (INIS)

    Le Marchand-Brustel, Y.; Ballotti, R.; Gremeaux, T.; Tanti, J.F.; Brandenburg, D.; Van Obberghen, E.

    1989-01-01

    Both receptor subunits were functionally labeled in order to provide methods allowing, in live cells and in broken cell systems, concomitant evaluation of the insulin receptor dual function, hormone binding, and kinase activity. In cell-free systems, insulin receptors were labeled on their alpha-subunit with 125I-photoreactive insulin, and on their beta-subunit by autophosphorylation. Thereafter, phosphorylated receptors were separated from the complete set of receptors by means of anti-phosphotyrosine antibodies. Using this approach, a subpopulation of receptors was found which had bound insulin, but which were not phosphorylated. Under nonreducing conditions, receptors appeared in three oligomeric species identified as alpha 2 beta 2, alpha 2 beta, and alpha 2. Mainly the alpha 2 beta 2 receptor species was found to be phosphorylated while insulin was bound to alpha 2 beta 2, alpha 2 beta, and alpha 2 forms. In live cells, biosynthetic labeling of insulin receptors was used. Receptors were first labeled with [35S]methionine. Subsequently, the addition of insulin led to receptor autophosphorylation by virtue of the endogenous ATP pool. The total amount of [35S]methionine-labeled receptors was precipitated with antireceptor antibodies, whereas with anti-phosphotyrosine antibodies, only the phosphorylated receptors were isolated. Using this approach we made the two following key findings: (1) Both receptor species, alpha 2 beta 2 and alpha 2 beta, are present in live cells and in comparable amounts. This indicates that the alpha 2 beta form is not a degradation product of the alpha 2 beta 2 form artificially generated during receptor preparation. (2) The alpha 2 beta 2 species is the prevalently autophosphorylated form

  10. Insulin receptors mediate growth effects in cultured fetal neurons. I. Rapid stimulation of protein synthesis

    International Nuclear Information System (INIS)

    Heidenreich, K.A.; Toledo, S.P.

    1989-01-01

    In this study we have examined the effects of insulin on protein synthesis in cultured fetal chick neurons. Protein synthesis was monitored by measuring the incorporation of [3H]leucine (3H-leu) into trichloroacetic acid (TCA)-precipitable protein. Upon addition of 3H-leu, there was a 5-min lag before radioactivity occurred in protein. During this period cell-associated radioactivity reached equilibrium and was totally recovered in the TCA-soluble fraction. After 5 min, the incorporation of 3H-leu into protein was linear for 2 h and was inhibited (98%) by the inclusion of 10 micrograms/ml cycloheximide. After 24 h of serum deprivation, insulin increased 3H-leu incorporation into protein by approximately 2-fold. The stimulation of protein synthesis by insulin was dose dependent (ED50 = 70 pM) and seen within 30 min. Proinsulin was approximately 10-fold less potent than insulin on a molar basis in stimulating neuronal protein synthesis. Insulin had no effect on the TCA-soluble fraction of 3H-leu at any time and did not influence the uptake of [3H]aminoisobutyric acid into neurons. The isotope ratio of 3H-leu/14C-leu in the leucyl tRNA pool was the same in control and insulin-treated neurons. Analysis of newly synthesized proteins by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that insulin uniformly increased the incorporation of 14C-leu into all of the resolved neuronal proteins. We conclude from these data that (1) insulin rapidly stimulates overall protein synthesis in fetal neurons independent of amino acid uptake and aminoacyl tRNA precursor pools; (2) stimulation of protein synthesis is mediated by the brain subtype of insulin receptor; and (3) insulin is potentially an important in vivo growth factor for fetal central nervous system neurons

  11. Effects of age and insulin-like growth factor-1 on rat neurotrophin receptor expression after nerve injury.

    Science.gov (United States)

    Luo, T David; Alton, Timothy B; Apel, Peter J; Cai, Jiaozhong; Barnwell, Jonathan C; Sonntag, William E; Smith, Thomas L; Li, Zhongyu

    2016-10-01

    Neurotrophin receptors, such as p75(NTR) , direct neuronal response to injury. Insulin-like growth factor-1 receptor (IGF-1R) mediates the increase in p75(NTR) during aging. The aim of this study was to examine the effect of aging and insulin-like growth factor-1 (IGF-1) treatment on recovery after peripheral nerve injury. Young and aged rats underwent tibial nerve transection with either local saline or IGF-1 treatment. Neurotrophin receptor mRNA and protein expression were quantified. Aged rats expressed elevated baseline IGF-1R (34% higher, P = 0.01) and p75(NTR) (68% higher, P < 0.01) compared with young rats. Post-injury, aged animals expressed significantly higher p75(NTR) levels (68.5% above baseline at 4 weeks). IGF-1 treatment suppressed p75(NTR) gene expression at 4 weeks (17.2% above baseline, P = 0.002) post-injury. Local IGF-1 treatment reverses age-related declines in recovery after peripheral nerve injuries by suppressing p75(NTR) upregulation and pro-apoptotic complexes. IGF-1 may be considered a viable adjuvant therapy to current treatment modalities. Muscle Nerve 54: 769-775, 2016. © 2016 Wiley Periodicals, Inc.

  12. Receptor-isoform-selective insulin analogues give tissue-preferential effects

    DEFF Research Database (Denmark)

    Vienberg, Sara Gry; Bouman, Stephan D; Sørensen, Heidi

    2011-01-01

    The relative expression patterns of the two IR (insulin receptor) isoforms, +/- exon 11 (IR-B/IR-A respectively), are tissue-dependent. Therefore we have developed insulin analogues with different binding affinities for the two isoforms to test whether tissue-preferential biological effects can...... be attained. In rats and mice, IR-B is the most prominent isoform in the liver (> 95%) and fat (> 90%), whereas in muscles IR-A is the dominant isoform (> 95%). As a consequence, the insulin analogue INS-A, which has a higher relative affinity for human IR-A, had a higher relative potency [compared with HI...... (human insulin)] for glycogen synthesis in rat muscle strips (26%) than for glycogen accumulation in rat hepatocytes (5%) and for lipogenesis in rat adipocytes (4%). In contrast, the INS-B analogue, which has an increased affinity for human IR-B, had higher relative potencies (compared with HI...

  13. The insulin receptor substrate (IRS)-1 pleckstrin homology domain functions in downstream signaling.

    Science.gov (United States)

    Vainshtein, I; Kovacina, K S; Roth, R A

    2001-03-16

    The pleckstrin homology (PH) domain of the insulin receptor substrate-1 (IRS-1) plays a role in directing this molecule to the insulin receptor, thereby regulating its tyrosine phosphorylation. In this work, the role of the PH domain in subsequent signaling was studied by constructing constitutively active forms of IRS-1 in which the inter-SH2 domain of the p85 subunit of phosphatidylinositol 3-kinase was fused to portions of the IRS-1 molecule. Chimeric molecules containing the PH domain were found to activate the downstream response of stimulating the Ser/Thr kinase Akt. A chimera containing point mutations in the PH domain that abolished the ability of this domain to bind phosphatidylinositol 4,5-bisphosphate prevented these molecules from activating Akt. These mutations also decreased by about 70% the amount of the constructs present in a particulate fraction of the cells. These results indicate that the PH domain of IRS-1, in addition to directing this protein to the receptor for tyrosine phosphorylation, functions in the ability of this molecule to stimulate subsequent responses. Thus, compromising the function of the PH domain, e.g. in insulin-resistant states, could decrease both the ability of IRS-1 to be tyrosine phosphorylated by the insulin receptor and to link to subsequent downstream targets.

  14. Cell-Cell Adhesion and Insulin-Like Growth Factor I Receptor in Breast Cancer

    National Research Council Canada - National Science Library

    Bartucci, Monica

    2001-01-01

    .... Our goal was to study the role of the insulin-like growth factor I receptor (IGF-IR) in breast cancer. The IGF-IR is a multifunctional tyrosine kinase that has been recently implicated in breast tumor development and progression...

  15. Characterization of the growth of murine fibroblasts that express human insulin receptors. I. The effect of insulin in the absence of other growth factors

    International Nuclear Information System (INIS)

    Randazzo, P.A.; Morey, V.A.; Polishook, A.K.; Jarett, L.

    1990-01-01

    The effect of insulin on the growth of murine fibroblasts transfected with an expression vector containing human insulin receptor cDNA (NIH 3T3/HIR) and the parental cells (NIH/3T3) was characterized. Insulin in the absence of other mitogens increased the rate of incorporation of thymidine into NIH 3T3/HIR cells with a half-maximal response occurring at an insulin concentration of 35 ng/ml and a maximal response that was equivalent to that elicited by 10% fetal calf serum. The thymidine incorporation rate was increased by 12 h, was maximal at approximately 16 h, and returned to basal rates at 24 h after the addition of insulin. Insulin induced a maximum of 65% of cells to incorporate thymidine. The increased DNA synthesis was accompanied by net growth. Addition of insulin to the NIH 3T3/HIR cells resulted in increased DNA content with a half-maximal response occurring at approximately 30 ng/ml insulin and a maximal response equivalent to that elicited by serum. An increase in cell number detected after the addition of insulin to the NIH 3T3/HIR suggests that the cells had progressed through mitosis. Insulin did not increase the rate of thymidine incorporation, DNA content, or number of the parental NIH 3T3 cells. These data show that insulin, in the absence of a second mitogen, is able to induce NIH 3T3/HIR fibroblasts to traverse the cell cycle

  16. Phenolic Compounds from Fermented Berry Beverages Modulated Gene and Protein Expression To Increase Insulin Secretion from Pancreatic β-Cells in Vitro.

    Science.gov (United States)

    Johnson, Michelle H; de Mejia, Elvira Gonzalez

    2016-03-30

    Berries are a rich source of bioactive phenolic compounds that are able to bind and inhibit the enzyme dipeptidyl peptidase-IV (DPP-IV), a current target for type-2 diabetes therapy. The objectives were to determine the role of berry phenolic compounds to modulate incretin-cleaving DPP-IV and its substrate glucagon-like peptide-1 (GLP-1), insulin secretion from pancreatic β-cells, and genes and proteins involved in the insulin secretion pathway using cell culture. Anthocyanins (ANC) from 50% blueberry-50% blackberry (Blu-Bla) and 100% blackberry (Bla) fermented beverages at 50 μM cyanidin-3-glucoside equivalents increased (p beverages have the potential to modulate DPP-IV and its substrate GLP-1, to increase insulin secretion, and to upregulate expression of mRNA of insulin-receptor associated genes and proteins in pancreatic β-cells.

  17. Cannabinoid CB2 receptor potentiates obesity-associated inflammation, insulin resistance and hepatic steatosis.

    Directory of Open Access Journals (Sweden)

    Vanessa Deveaux

    Full Text Available BACKGROUND: Obesity-associated inflammation is of critical importance in the development of insulin resistance and non-alcoholic fatty liver disease. Since the cannabinoid receptor CB2 regulates innate immunity, the aim of the present study was to investigate its role in obesity-induced inflammation, insulin resistance and fatty liver. METHODOLOGY: Murine obesity models included genetically leptin-deficient ob/ob mice and wild type (WT mice fed a high fat diet (HFD, that were compared to their lean counterparts. Animals were treated with pharmacological modulators of CB2 receptors. Experiments were also performed in mice knock-out for CB2 receptors (Cnr2 -/-. PRINCIPAL FINDINGS: In both HFD-fed WT mice and ob/ob mice, Cnr2 expression underwent a marked induction in the stromal vascular fraction of epididymal adipose tissue that correlated with increased fat inflammation. Treatment with the CB2 agonist JWH-133 potentiated adipose tissue inflammation in HFD-fed WT mice. Moreover, cultured fat pads isolated from ob/ob mice displayed increased Tnf and Ccl2 expression upon exposure to JWH-133. In keeping, genetic or pharmacological inactivation of CB2 receptors decreased adipose tissue macrophage infiltration associated with obesity, and reduced inductions of Tnf and Ccl2 expressions. In the liver of obese mice, Cnr2 mRNA was only weakly induced, and CB2 receptors moderately contributed to liver inflammation. HFD-induced insulin resistance increased in response to JWH-133 and reduced in Cnr2 -/- mice. Finally, HFD-induced hepatic steatosis was enhanced in WT mice treated with JWH-133 and blunted in Cnr2 -/- mice. CONCLUSION/SIGNIFICANCE: These data unravel a previously unrecognized contribution of CB2 receptors to obesity-associated inflammation, insulin resistance and non-alcoholic fatty liver disease, and suggest that CB2 receptor antagonists may open a new therapeutic approach for the management of obesity-associated metabolic disorders.

  18. Relationships among Body Condition, Insulin Resistance and Subcutaneous Adipose Tissue Gene Expression during the Grazing Season in Mares.

    Directory of Open Access Journals (Sweden)

    Shaimaa Selim

    Full Text Available Obesity and insulin resistance have been shown to be risk factors for laminitis in horses. The objective of the study was to determine the effect of changes in body condition during the grazing season on insulin resistance and the expression of genes associated with obesity and insulin resistance in subcutaneous adipose tissue (SAT. Sixteen Finnhorse mares were grazing either on cultivated high-yielding pasture (CG or semi-natural grassland (NG from the end of May to the beginning of September. Body measurements, intravenous glucose tolerance test (IVGTT, and neck and tailhead SAT gene expressions were measured in May and September. At the end of grazing, CG had higher median body condition score (7 vs. 5.4, interquartile range 0.25 vs. 0.43; P=0.05 and body weight (618 kg vs. 572 kg ± 10.21 (mean ± SEM; P=0.02, and larger waist circumference (P=0.03 than NG. Neck fat thickness was not different between treatments. However, tailhead fat thickness was smaller in CG compared to NG in May (P=0.04, but this difference disappeared in September. Greater basal and peak insulin concentrations, and faster glucose clearance rate (P=0.03 during IVGTT were observed in CG compared to NG in September. A greater decrease in plasma non-esterified fatty acids during IVGTT (P<0.05 was noticed in CG compared to NG after grazing. There was down-regulation of insulin receptor, retinol binding protein 4, leptin, and monocyte chemoattractant protein-1, and up-regulation of adiponectin (ADIPOQ, adiponectin receptor 1 and stearoyl-CoA desaturase (SCD gene expressions in SAT of both groups during the grazing season (P<0.05. Positive correlations were observed between ADIPOQ and its receptors and between SCD and ADIPOQ in SAT (P<0.01. In conclusion, grazing on CG had a moderate effect on responses during IVGTT, but did not trigger insulin resistance. Significant temporal differences in gene expression profiles were observed during the grazing season.

  19. Glucose Induces Mouse β-Cell Proliferation via IRS2, MTOR, and Cyclin D2 but Not the Insulin Receptor

    Science.gov (United States)

    Stamateris, Rachel E.; Sharma, Rohit B.; Kong, Yahui; Ebrahimpour, Pantea; Panday, Deepika; Ranganath, Pavana; Zou, Baobo; Levitt, Helena; Parambil, Nisha Abraham; O’Donnell, Christopher P.; García-Ocaña, Adolfo

    2016-01-01

    An important goal in diabetes research is to understand the processes that trigger endogenous β-cell proliferation. Hyperglycemia induces β-cell replication, but the mechanism remains debated. A prime candidate is insulin, which acts locally through the insulin receptor. Having previously developed an in vivo mouse hyperglycemia model, we tested whether glucose induces β-cell proliferation through insulin signaling. By using mice lacking insulin signaling intermediate insulin receptor substrate 2 (IRS2), we confirmed that hyperglycemia-induced β-cell proliferation requires IRS2 both in vivo and ex vivo. Of note, insulin receptor activation was not required for glucose-induced proliferation, and insulin itself was not sufficient to drive replication. Glucose and insulin caused similar acute signaling in mouse islets, but chronic signaling differed markedly, with mammalian target of rapamycin (MTOR) and extracellular signal–related kinase (ERK) activation by glucose and AKT activation by insulin. MTOR but not ERK activation was required for glucose-induced proliferation. Cyclin D2 was necessary for glucose-induced β-cell proliferation. Cyclin D2 expression was reduced when either IRS2 or MTOR signaling was lost, and restoring cyclin D2 expression rescued the proliferation defect. Human islets shared many of these regulatory pathways. Taken together, these results support a model in which IRS2, MTOR, and cyclin D2, but not the insulin receptor, mediate glucose-induced proliferation. PMID:26740601

  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. Insulin-like growth factor-II receptors in cultured rat hepatocytes: regulation by cell density

    International Nuclear Information System (INIS)

    Scott, C.D.; Baxter, R.C.

    1987-01-01

    Insulin-like growth factor-II (IGF-II) receptors in primary cultures of adult rat hepatocytes were characterized and their regulation by cell density examined. In hepatocytes cultured at 5 X 10(5) cells per 3.8 cm2 plate [ 125 I]IGF-II bound to specific, high affinity receptors (Ka = 4.4 +/- 0.5 X 10(9) l/mol). Less than 1% cross-reactivity by IGF-I and no cross-reactivity by insulin were observed. IGF-II binding increased when cells were permeabilized with 0.01% digitonin, suggesting the presence of an intracellular receptor pool. Determined by Scatchard analysis and by polyacrylamide gel electrophoresis after affinity labeling, the higher binding was due solely to an increase in binding sites present on 220 kDa type II IGF receptors. In hepatocytes cultured at low densities, the number of cell surface receptors increased markedly, from 10-20,000 receptors per cell at a culture density of 6 X 10(5) cells/well to 70-80,000 receptors per cell at 0.38 X 10(5) cells/well. The increase was not due simply to the exposure of receptors from the intracellular pool, as a density-related increase in receptors was also seen in cells permeabilized with digitonin. There was no evidence that IGF binding proteins, either secreted by hepatocytes or present in fetal calf serum, had any effect on the measurement of receptor concentration or affinity. We conclude that rat hepatocytes in primary culture contain specific IGF-II receptors and that both cell surface and intracellular receptors are regulated by cell density

  2. Angiotensin-II type 1 receptor gene polymorphism and diabetic microangiopathy

    DEFF Research Database (Denmark)

    Tarnow, L; Cambien, Francois; Rossing, P

    1996-01-01

    with proliferative retinopathy and without diabetic retinopathy was found either: 77 (50%) / 66 (42%) / 13 (8%) vs. 42 (63%) / 22 (33%) / 3 (4%) had AA/AC/CC genotypes, respectively. CONCLUSIONS: The A1166-->C polymorphism in the angiotensin-II type 1 receptor gene does not contribute to the genetic susceptibility...... is present particularly in vascular smooth muscle cells, myocardium and the kidney. A transversion of adenine to cytosine at nucleotide position 1166 in the gene coding for the angiotensin-II type 1 receptor has been associated with hypertension in the non-diabetic population. METHODS: We studied...... the relationship between the A1166-->C polymorphism in the angiotensin-II type 1 receptor gene in patients with insulin dependent diabetes mellitus (IDDM) and diabetic nephropathy (121 men, 77 women, age 41 +/- 10 years, diabetes duration 27 +/- 8 years) and in IDDM patients with normoalbuminuria (116 men, 74...

  3. Characterization of the insulin sensitivity of ghrelin receptor KO mice using glycemic clamps

    Directory of Open Access Journals (Sweden)

    Morgan Kristen

    2011-01-01

    Full Text Available Abstract Background We and others have demonstrated previously that ghrelin receptor (GhrR knock out (KO mice fed a high fat diet (HFD have increased insulin sensitivity and metabolic flexibility relative to WT littermates. A striking feature of the HFD-fed GhrR KO mouse is the dramatic decrease in hepatic steatosis. To characterize further the underlying mechanisms of glucose homeostasis in GhrR KO mice, we conducted both hyperglycemic (HG and hyperinsulinemic-euglycemic (HI-E clamps. Additionally, we investigated tissue glucose uptake and specifically examined liver insulin sensitivity. Results Consistent with glucose tolerance-test data, in HG clamp experiments, GhrR KO mice showed a reduction in glucose-stimulated insulin release relative to WT littermates. Nevertheless, a robust 1st phase insulin secretion was still achieved, indicating that a healthy β-cell response is maintained. Additionally, GhrR KO mice demonstrated both a significantly increased glucose infusion rate and significantly reduced insulin requirement for maintenance of the HG clamp, consistent with their relative insulin sensitivity. In HI-E clamps, both LFD-fed and HFD-fed GhrR KO mice showed higher peripheral insulin sensitivity relative to WT littermates as indicated by a significant increase in insulin-stimulated glucose disposal (Rd, and decreased hepatic glucose production (HGP. HFD-fed GhrR KO mice showed a marked increase in peripheral tissue glucose uptake in a variety of tissues, including skeletal muscle, brown adipose tissue and white adipose tissue. GhrR KO mice fed a HFD also showed a modest, but significant decrease in conversion of pyruvate to glucose, as would be anticipated if these mice displayed increased liver insulin sensitivity. Additionally, the levels of UCP2 and UCP1 were reduced in the liver and BAT, respectively, in GhrR KO mice relative to WT mice. Conclusions These results indicate that improved glucose homeostasis of GhrR KO mice is

  4. The Biased G-Protein-Coupled Receptor Agonism Bridges the Gap between the Insulin Receptor and the Metabolic Syndrome

    Science.gov (United States)

    Liauchonak, Iryna; Dawoud, Fady; Riat, Yatin; Sambi, Manpreet; Jain, Justin; Kalaydina, Regina-Veronicka; Mendonza, Nicole; Bajwa, Komal

    2018-01-01

    Insulin signaling, as mediated through the insulin receptor (IR), plays a critical role in metabolism. Aberrations in this signaling cascade lead to several pathologies, the majority of which are classified under the umbrella term “metabolic syndrome”. Although many of these pathologies are associated with insulin resistance, the exact mechanisms are not well understood. One area of current interest is the possibility of G-protein-coupled receptors (GPCRs) influencing or regulating IR signaling. This concept is particularly significant, because GPCRs have been shown to participate in cross-talk with the IR. More importantly, GPCR signaling has also been shown to preferentially regulate specific downstream signaling targets through GPCR agonist bias. A novel study recently demonstrated that this GPCR-biased agonism influences the activity of the IR without the presence of insulin. Although GPCR-IR cross-talk has previously been established, the notion that GPCRs can regulate the activation of the IR is particularly significant in relation to metabolic syndrome and other pathologies that develop as a result of alterations in IR signaling. As such, we aim to provide an overview of the physiological and pathophysiological roles of the IR within metabolic syndrome and its related pathologies, including cardiovascular health, gut microflora composition, gastrointestinal tract functioning, polycystic ovarian syndrome, pancreatic cancer, and neurodegenerative disorders. Furthermore, we propose that the GPCR-biased agonism may perhaps mediate some of the downstream signaling effects that further exacerbate these diseases for which the mechanisms are currently not well understood. PMID:29462993

  5. Adenovirus E4-ORF1 Dysregulates Epidermal Growth Factor and Insulin/Insulin-Like Growth Factor Receptors To Mediate Constitutive Myc Expression

    OpenAIRE

    Kong, Kathleen; Kumar, Manish; Taruishi, Midori; Javier, Ronald T.

    2015-01-01

    The E4-ORF1 protein encoded by human adenovirus stimulates viral replication in human epithelial cells by binding and activating cellular phosphatidylinositol 3-kinase (PI3K) at the plasma membrane and cellular Myc in the nucleus. In this study, we showed that E4-ORF1 hijacks the tyrosine kinase activities of cellular epidermal growth factor receptor (EGFR) and insulin receptor (InsR)/insulin-like growth factor receptor 1 (IGF1R), as well as the lipid kinase activity of PI3K, to mediate const...

  6. Relationship between tyrosine phosphorylation and protein expression of insulin receptor and insulin resistance in gestational diabetes mellitus.

    Science.gov (United States)

    Chu, Yong-li; Gong, Yu-dian; Su, Zhi-hui; Yu, Hong-na; Cui, Qing; Jiang, Hai-yang; Qu, Hong-mei

    2014-06-01

    The relationship between tyrosine phosphorylation (TP) and protein expression of insulin receptor (InsR) and insulin resistance (IR) in patients with gestational diabetes mellitus (GDM) was investigated. The InsR expression and TP in skeleton muscle tissue were determined by Western blotting and immunoprecipitation in women with GDM (GDM group, n=22), normal pregnant women (normal pregnancy group, n=22) and normal non-pregnant women (normal non-pregnant group, n=13). Fasting plasma glucose (FPG) and fasting insulin (FINS) were measured by oxidase assay and immunoradioassay. The results showed that the levels of FPG (5.61±0.78 mmol/L), FINS (15.42±5.13 mU/L) and Homeostasis model assessment-IR (HOMA-IR) (1.21±0.52) in GDM group were significantly higher than those in normal pregnancy group (4.43±0.46 mmol/L, 10.56±3.07 mU/L and 0.80±0.31 respectively) (Ppregnant group (7.56±2.31 mU/L and 0.47±0.26 respectively) (P0.05). TP of InsR with insulin stimulation was significantly decreased in GDM group (0.20±0.05) as compared with normal pregnancy group (0.26±0.06) (Pinsulin stimulation in normal pregnancy group was lower than that in normal non-pregnant group (0.31±0.06) (Pinsulin stimulation was negatively related with HOMA-IR in GDM group (r=-0.525, P0.05). It was suggested that there is no significant correlation between the protein expression of InsR in skeletal muscle and IR in GDM, but changes in TP of InsR are associated with IR in GDM.

  7. Relaxin, its receptor (RXFP1), and insulin-like peptide 4 expression through gestation and in placenta accreta.

    Science.gov (United States)

    Goh, William; Yamamoto, Sandra Y; Thompson, Karen S; Bryant-Greenwood, Gillian D

    2013-08-01

    This study was designed to show whether placental relaxin (RLN), its receptor (RXFP1), or insulin-like peptide 4 (INSL4) might have altered expression in patients with placenta accreta. The baseline expression of their genes through gestation (n = 34) was quantitated in the placental basal plate (BP) and villous trophoblast (TR), and compared to their expression in placenta accreta (n = 6). The proteins were also immunolocalized and quantitated in the accreta tissues. The messenger RNAs (mRNAs) of matrix metalloproteinase 9, -2, and tissue inhibitors of matrix metalloproteinase (TIMP)-1 were also measured. Results demonstrated that the BP and TR expressed low levels of RLN/RXFP1 and INSL4 through gestation. In accreta, increased RLN gene and protein in BP were associated with antepartum bleeding whereas INSL4 expression decreased throughout the TR. There were no changes in mRNAs for MMPs, but TIMP-1 was increased only in the invasive TR.

  8. 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.

  9. Internalized insulin-receptor complexes are unidirectionally translocated to chloroquine-sensitive degradative sites. Dependence on metabolic energy

    International Nuclear Information System (INIS)

    Berhanu, P.

    1988-01-01

    Insulin receptors on the surface of isolated rat adipocytes were photoaffinity labeled at 12 degrees C with the iodinated photoreactive insulin analogue, 125I-B2 (2-nitro-4-azidophenylacetyl)-des-PheB1-insulin, and the pathways in the intracellular processing of the labeled receptors were studied at 37 degrees C. During 37 degrees C incubations, the labeled 440-kDa insulin receptors were continuously internalized (as assessed by trypsin inaccessibility) and degraded such that up to 50% of the initially labeled receptors were lost by 120 min. Metabolic poisons (0.125-0.75 mM 2,4-dinitrophenol (DNP) and 1-10 mM NaF), which led to dose-dependent depletion of adipocyte ATP pools, inhibited receptor loss, and caused up to 3-fold increase in intracellular receptor accumulation. This effect was due to inhibition of intracellular receptor degradation, and there was no apparent effect of the metabolic poisons on initial internalization of the receptors. Following maximal intracellular accumulation of labeled insulin receptors in the presence of NaF or DNP, removal of these agents resulted in a subsequent, time-dependent degradation of the accumulated receptors. However, when the lysosomotropic agent, chloroquine (0.2 mM), was added immediately following removal of the metabolic poisons, further degradation of the intracellularly accumulated receptors was prevented, suggesting that the chloroquine-sensitive degradation of insulin receptors occurs distal to the site of inhibition by NaF or DNP. To confirm this, maximal intracellular accumulation of labeled receptors was first allowed to occur in the presence of chloroquine and the cells were then washed and reincubated in chloroquine-free media in the absence or presence of NaF or DNP. Under these conditions, degradation of the intracellularly accumulated receptors continued to occur, and NaF or DNP failed to block the degradation

  10. High-level expression of human insulin receptor cDNA in mouse NIH 3T3 cells

    International Nuclear Information System (INIS)

    Whittaker, J.; Okamoto, A.K.; Thys, R.; Bell, G.I.; Steiner, D.F.; Hofmann, C.A.

    1987-01-01

    In order to develop a simple, efficient system for the high-level expression of human insulin receptors in eukaryotic cells, a full-length human kidney insulin receptor cDNA was inserted into a bovine papilloma virus vector under the control of the mouse metallothionein promoter. After transfection of mouse NIH 3T3 cells with this construct, seven cell lines expressing insulin receptors were isolated; two cell lines had more than 10 6 receptors per cell. The cell line with the highest 125 I-insulin binding (NIH 3T3 HIR3.5) had 6 x 10 6 receptors with a K/sub d/ of 10 -9 M. This level was not dependent on exposure to metals but could be increased further to 2 x 10 7 receptors per cell by addition of sodium butyrate to the culture medium. The α and β subunits had apparent molecular weights of 147,000 and 105,000, respectively (compared to 135,000 and 95,000 in IM-9 human lymphocytes), values identical to those of the α and β subunits of the insulin receptors of nontransformed NIH 3T3 cells. This size difference was due to altered carbohydrate composition, as N-glycanase digestion reduced the apparent receptor subunit size of the transfected cells and IM-9 lymphocytes to identical values. The alteration in N-linked oligosaccharide composition could not be ascribed to differences in the kinetics of posttranslational processing of the insulin receptors, which was comparable to that of other cells studied. The basal rate of glycogen synthesis in the cells overexpressing insulin receptors was increased 4- to 5-fold compared with controls. Low levels of added insulin (0.1 nM) caused a 50% increase in the rate of glycogen synthesis

  11. Consolidation of long-term memory by insulin in Lymnaea is not brought about by changing the number of insulin receptors.

    Science.gov (United States)

    Hatakeyama, Dai; Okuta, Akiko; Otsuka, Emi; Lukowiak, Ken; Ito, Etsuro

    2013-05-01

    The pond snail Lymnaea stagnalis learns taste aversion and consolidates it into long-term memory (LTM). This is referred to as conditioned taste aversion (CTA). The superfusion of molluscan insulin-related peptides (MIPs) over the isolated snail brain causes a long-term enhancement of synaptic input between the cerebral giant cell and the B1 buccal motor neuron. This enhancement is hypothesized to underlie CTA. The synaptic enhancement caused by the superfusion of MIPs can be blocked by the application of human insulin receptor antibody, which recognizes the extracellular domain of human insulin receptor and acts as an antagonist even for MIP receptors. An injection of the human insulin receptor antibody into the abdominal cavity of trained snails blocks the consolidation process leading to LTM, even though the snails acquire taste aversion. Here, we examined whether or not taste-aversion training changes the mRNA expression level of MIP receptor in the snail brain and found that it does not. This result, taken together with previous findings, suggest that the MIPs' effect on synaptic function in the snail brain is attributable to a change in the MIP concentration, and not to a change in the mRNA expression level of MIP receptor, which is thought to reflect the number of MIP receptors.

  12. SH2-Balpha is an insulin-receptor adapter protein and substrate that interacts with the activation loop of the insulin-receptor kinase.

    OpenAIRE

    Kotani, K; Wilden, P; Pillay, T S

    1998-01-01

    We identified SH2-Balpha as an insulin-receptor-binding protein based on interaction screening in yeast hybrid systems and co-precipitation in cells. SH2-Balpha contains pleckstrin-homology ('PH') and Src homology 2 (SH2) domains and is closely related to APS (adapter protein with a PH domain and an SH2 domain) and lnk, adapter proteins first identified in lymphocytes. SH2-Balpha is ubiquitously expressed and is present in rat epididymal adipose tissue, liver and skeletal muscle, physiologica...

  13. 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

  14. Polymorphisms in the vitamin D receptor gene and the androgen receptor gene and the risk of benign prostatic hyperplasia

    NARCIS (Netherlands)

    Bousema, J. T.; Bussemakers, M. J.; van Houwelingen, K. P.; Debruyne, F. M.; Verbeek, A. L.; de la Rosette, J. J.; Kiemeney, L. A.

    2000-01-01

    Little is known about risk factors for the development of benign prostatic hyperplasia (BPH). Recently, associations were observed between prostate cancer (CaP) risk and polymorphisms in the vitamin D receptor (VDR) gene and the androgen receptor (AR) gene. Since both receptors are relevant for

  15. Sex differences and left-right asymmetries in expression of insulin and insulin-like growth factor-1 receptors in developing rat hippocampus.

    Science.gov (United States)

    Hami, Javad; Sadr-Nabavi, Ariane; Sankian, Mojtaba; Haghir, Hossein

    2012-04-01

    Sex differences and laterality of rat hippocampus with respect to insulin-like growth factor-1 receptor (IGF-1R) and insulin receptor (InsR) expression as two important contributors to/regulators of developmental and cognitive functions were examined using real-time PCR and western blot analysis at P0, P7 and P14. Expression of the IGF-1R gene was lowest at P0 in all studied hippocampi. In males, we found the highest expression at P7 in the right hippocampus, and at P14 in the left one. In contrast, the peaked IGF-1R expression occurred at P7 in female hippocampi independent of laterality. Hippocampal InsR expression in males decreased significantly between P0 and P7, followed by a marked upregulation at P14. Conversely, the expression of InsR in females peaked at P7 and then decreased again significantly at P14. We found significant interhemispheric differences in IGF-1R mRNA levels in both male and female hippocampi at different time points. In contrast, we only found significant interhemispheric differences in InsR mRNA expression in P14 male rats, with higher values in the left hippocampus. Interestingly, changes in mRNA expression and in protein levels followed the same developmental pattern, indicating that IGF-1R and InsR transcription is not subject to modulatory effects during the first two weeks of development. These findings indicate that there are prominent interhemispheric and sex differences in IGF-1R and InsR expression in the developing rat hippocampus, suggesting a probable mechanism for the control of gender and laterality differences in development and function of the hippocampus.

  16. Hyperosmotic stress inhibits insulin receptor substrate-1 function by distinct mechanisms in 3T3-L1 adipocytes

    DEFF Research Database (Denmark)

    Gual, Philippe; Gonzalez, Teresa; Grémeaux, Thierry

    2003-01-01

    . Furthermore, the mammalian target of rapamycin (mTOR) inhibitor rapamycin prevented the osmotic shock-induced phosphorylation of IRS-1 on Ser307. The inhibition of mTOR completely reversed the inhibitory effect of hyperosmotic stress on insulin-induced IRS-1 tyrosine phosphorylation and PI 3-kinase activation......In 3T3-L1 adipocytes, hyperosmotic stress was found to inhibit insulin signaling, leading to an insulin-resistant state. We show here that, despite normal activation of insulin receptor, hyperosmotic stress inhibits both tyrosine phosphorylation of insulin receptor substrate-1 (IRS-1) and IRS-1....... In addition, prolonged osmotic stress enhanced the degradation of IRS proteins through a rapamycin-insensitive pathway and a proteasome-independent process. These data support evidence of new mechanisms involved in osmotic stress-induced cellular insulin resistance. Short-term osmotic stress induces...

  17. The Androgen Receptor Gene Mutations Database.

    Science.gov (United States)

    Gottlieb, B; Lehvaslaiho, H; Beitel, L K; Lumbroso, R; Pinsky, L; Trifiro, M

    1998-01-01

    The current version of the androgen receptor (AR) gene mutations database is described. The total number of reported mutations has risen from 272 to 309 in the past year. We have expanded the database: (i) by giving each entry an accession number; (ii) by adding information on the length of polymorphic polyglutamine (polyGln) and polyglycine (polyGly) tracts in exon 1; (iii) by adding information on large gene deletions; (iv) by providing a direct link with a completely searchable database (courtesy EMBL-European Bioinformatics Institute). The addition of the exon 1 polymorphisms is discussed in light of their possible relevance as markers for predisposition to prostate or breast cancer. The database is also available on the internet (http://www.mcgill. ca/androgendb/ ), from EMBL-European Bioinformatics Institute (ftp. ebi.ac.uk/pub/databases/androgen ), or as a Macintosh FilemakerPro or Word file (MC33@musica.mcgill.ca).

  18. One week treatment with the IL-1 receptor antagonist anakinra leads to a sustained improvement in insulin sensitivity in insulin resistant patients with type 1 diabetes mellitus.

    Science.gov (United States)

    van Asseldonk, Edwin J P; van Poppel, Pleun C M; Ballak, Dov B; Stienstra, Rinke; Netea, Mihai G; Tack, Cees J

    2015-10-01

    Inflammation associated with obesity is involved in the development of insulin resistance. We hypothesized that anti-inflammatory treatment with the Interleukin-1 receptor antagonist anakinra would improve insulin sensitivity. In an open label proof-of-concept study, we included overweight patients diagnosed with type 1 diabetes with an HbA1c level over 7.5%. Selecting insulin resistant patients with longstanding type 1 diabetes allowed us to study the effects of anakinra on insulin sensitivity. Patients were treated with 100mg anakinra daily for one week. Insulin sensitivity, insulin need and blood glucose profiles were measured before, after one week and after four weeks of follow-up. Fourteen patients completed the study. One week of anakinra treatment led to an improvement of insulin sensitivity, an effect that was sustained for four weeks. Similarly, glucose profiles, HbA1c levels and insulin needs improved. In conclusion, one week of treatment with anakinra improves insulin sensitivity in patients with type 1 diabetes. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. Differential subcellular localization of insulin receptor substrates depends on C-terminal regions and importin β

    International Nuclear Information System (INIS)

    Kabuta, Tomohiro; Take, Kazumi; Kabuta, Chihana; Hakuno, Fumihiko; Takahashi, Shin-Ichiro

    2008-01-01

    Insulin receptor substrates (IRSs) play essential roles in signal transduction of insulin and insulin-like growth factors. Previously, we showed that IRS-3 is localized to the nucleus as well as the cytosol, while IRS-1 and 2 are mainly localized to the cytoplasm. In the present study, we found that importin β directly interacts with IRS-3 and is able to mediate nuclear transport of IRS-3. Importin β interacted with the pleckstrin homology domain, the phosphotyrosine binding domain and the C-terminal region of IRS-3; indeed all of these fragments exhibited predominant nuclear localization. By contrast, almost no interaction of importin β with IRS-1 and -2 was observed, and their C-terminal regions displayed discrete spotty images in the cytosol. In addition, using chimeric proteins between IRS-1 and IRS-3, we revealed that the C-terminal regions are the main determinants of the differing subcellular localizations of IRS-1 and IRS-3.

  20. Candidate gene association study in type 2 diabetes indicates a role for genes involved in beta-cell function as well as insulin action.

    Directory of Open Access Journals (Sweden)

    Inês Barroso

    2003-10-01

    Full Text Available Type 2 diabetes is an increasingly common, serious metabolic disorder with a substantial inherited component. It is characterised by defects in both insulin secretion and action. Progress in identification of specific genetic variants predisposing to the disease has been limited. To complement ongoing positional cloning efforts, we have undertaken a large-scale candidate gene association study. We examined 152 SNPs in 71 candidate genes for association with diabetes status and related phenotypes in 2,134 Caucasians in a case-control study and an independent quantitative trait (QT cohort in the United Kingdom. Polymorphisms in five of 15 genes (33% encoding molecules known to primarily influence pancreatic beta-cell function-ABCC8 (sulphonylurea receptor, KCNJ11 (KIR6.2, SLC2A2 (GLUT2, HNF4A (HNF4alpha, and INS (insulin-significantly altered disease risk, and in three genes, the risk allele, haplotype, or both had a biologically consistent effect on a relevant physiological trait in the QT study. We examined 35 genes predicted to have their major influence on insulin action, and three (9%-INSR, PIK3R1, and SOS1-showed significant associations with diabetes. These results confirm the genetic complexity of Type 2 diabetes and provide evidence that common variants in genes influencing pancreatic beta-cell function may make a significant contribution to the inherited component of this disease. This study additionally demonstrates that the systematic examination of panels of biological candidate genes in large, well-characterised populations can be an effective complement to positional cloning approaches. The absence of large single-gene effects and the detection of multiple small effects accentuate the need for the study of larger populations in order to reliably identify the size of effect we now expect for complex diseases.

  1. Converting Insulin-like Growth Factors 1 and 2 into High-Affinity Ligands for Insulin Receptor Isoform A by the Introduction of an Evolutionarily Divergent Mutation

    Czech Academy of Sciences Publication Activity Database

    Macháčková, Kateřina; Chrudinová, Martina; Radosavljević, Jelena; Potalitsyn, Pavlo; Křížková, Květoslava; Fábry, Milan; Selicharová, Irena; Collinsová, Michaela; Brzozowski, A. M.; Žáková, Lenka; Jiráček, Jiří

    2018-01-01

    Roč. 57, č. 16 (2018), s. 2373-2382 ISSN 0006-2960 R&D Projects: GA ČR GA15-19018S Institutional support: RVO:61388963 ; RVO:68378050 Keywords : insulin-like growth factor * insulin * receptor * analog Subject RIV: CE - Biochemistry OBOR OECD: Biochemistry and molecular biology Impact factor: 2.938, year: 2016 https://pubs.acs.org/doi/10.1021/acs.biochem.7b01260

  2. 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.

  3. Human insulin analogues modified at the B26 site reveal a hormone conformation that is undetected in the receptor complex

    Czech Academy of Sciences Publication Activity Database

    Žáková, Lenka; Kletvíková, Emília; Lepšík, Martin; Collinsová, Michaela; Watson, C. J.; Turkenburg, J. P.; Jiráček, Jiří; Brzozowski, A. M.

    2014-01-01

    Roč. 70, č. 10 (2014), s. 2765-2774 ISSN 0907-4449 R&D Projects: GA ČR GPP207/11/P430; GA ČR GBP208/12/G016 Institutional support: RVO:61388963 Keywords : insulin * insulin receptor * complex * active form * analog * structure Subject RIV: CE - Biochemistry Impact factor: 7.232, year: 2013

  4. Mactosylceramide Prevents Glial Cell Overgrowth by Inhibiting Insulin and Fibroblast Growth Factor Receptor Signaling

    DEFF Research Database (Denmark)

    Gerdøe-Kristensen, Stine; Lund, Viktor K; Wandall, Hans H

    2017-01-01

    , in which the mannosyltransferase Egghead controls conversion of glucosylceramide (GlcCer) to mactosylceramide (MacCer). Lack of elongated GSL in egghead (egh) mutants causes overgrowth of subperineurial glia (SPG), largely due to aberrant activation of phosphatidylinositol 3-kinase (PI3K). However, to what...... of the Drosophila Insulin Receptor (InR) and the FGFR homolog Heartless (Htl) in wild type SPG, and is suppressed by inhibiting Htl and InR activity in egh. Knockdown of GlcCer synthase in the SPG fails to suppress glial overgrowth in egh nerves, and slightly promotes overgrowth in wild type, suggesting that RTK...... hyperactivation is caused by absence of MacCer and not by GlcCer accumulation. We conclude that an early product in GSL biosynthesis, MacCer, prevents inappropriate activation of Insulin and Fibroblast Growth Factor Receptors in Drosophila glia. This article is protected by copyright. All rights reserved....

  5. Discovery of OSI-906: a selective and orally efficacious dual inhibitor of the IGF-1 receptor and insulin receptor.

    Science.gov (United States)

    Mulvihill, Mark J; Cooke, Andrew; Rosenfeld-Franklin, Maryland; Buck, Elizabeth; Foreman, Ken; Landfair, Darla; O'Connor, Matthew; Pirritt, Caroline; Sun, Yingchaun; Yao, Yan; Arnold, Lee D; Gibson, Neil W; Ji, Qun-Sheng

    2009-09-01

    The IGF-1 receptor (IGF-1R) has been implicated in the promotion of tumorigenesis, metastasis and resistance to cancer therapies. Therefore, this receptor has become a major focus for the development of anticancer agents. Our lead optimization efforts that blended structure-based design and empirical medicinal chemistry led to the discovery of OSI-906, a novel small-molecule dual IGF-1R/insulin receptor (IR) kinase inhibitor. OSI-906 potently and selectively inhibits autophosphorylation of both human IGF-1R and IR, displays in vitro antiproliferative effects in a variety of tumor cell lines and shows robust in vivo anti-tumor efficacy in an IGF-1R-driven xenograft model when administered orally once daily. OSI-906 is a novel, potent, selective and orally bioavailable dual IGF-1R/IR kinase inhibitor with favorable preclinical drug-like properties, which has demonstrated in vivo efficacy in tumor models and is currently in clinical testing.

  6. Insulin-Insulin-like Growth Factors Hybrids as Molecular Probes of Hormone:Receptor Binding Specificity

    Czech Academy of Sciences Publication Activity Database

    Křížková, Květoslava; Chrudinová, Martina; Povalová, Anna; Selicharová, Irena; Collinsová, Michaela; Vaněk, Václav; Brzozowski, A. M.; Jiráček, Jiří; Žáková, Lenka

    2016-01-01

    Roč. 55, č. 21 (2016), s. 2903-2913 ISSN 0006-2960 R&D Projects: GA ČR GA15-19018S Institutional support: RVO:61388963 Keywords : alanine scanning mutagenesis * high-affinity binding * type 1 IGF receptor Subject RIV: CE - Biochemistry Impact factor: 2.938, year: 2016 http://pubs.acs.org/doi/pdf/10.1021/acs.biochem.6b00140

  7. 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

  8. Targeting non-small cell lung cancer cells by dual inhibition of the insulin receptor and the insulin-like growth factor-1 receptor.

    Directory of Open Access Journals (Sweden)

    Emma E Vincent

    Full Text Available Phase III trials of the anti-insulin-like growth factor-1 receptor (IGF1R antibody figitumumab in non-small cell lung cancer (NSCLC patients have been discontinued owing to lack of survival benefit. We investigated whether inhibition of the highly homologous insulin receptor (IR in addition to the IGF1R would be more effective than inhibition of the IGF1R alone at preventing the proliferation of NSCLC cells. Signalling through IGF1R and IR in the NSCLC cell lines A549 and Hcc193 was stimulated by a combination of IGF1, IGF2 and insulin. It was inhibited by antibodies that block ligand binding, αIR3 (IGF1R and IR47-9 (IR, and by the ATP-competitive small molecule tyrosine kinase inhibitors AZ12253801 and NVPAWD742 which inhibit both IGF1R and IR tyrosine kinases. The effect of inhibitors was determined by an anchorage-independent proliferation assay and by analysis of Akt phosphorylation. In Hcc193 cells the reduction in cell proliferation and Akt phosphorylation due to anti-IGF1R antibody was enhanced by antibody-mediated inhibition of the IR whereas in A549 cells, with a relatively low IR:IGF1R expression ratio, it was not. In each cell line proliferation and Akt phosphorylation were more effectively inhibited by AZ12253801 and NVPAWD742 than by combined αIR3 and IR47-9. When the IGF1R alone is inhibited, unencumbered signalling through the IR can contribute to continued NSCLC cell proliferation. We conclude that small molecule inhibitors targeting both the IR and IGF1R more effectively reduce NSCLC cell proliferation in a manner independent of the IR:IGF1R expression ratio, providing a therapeutic rationale for the treatment of this disease.

  9. Interactive roles of Ras, insulin receptor substrate-1, and proteins with Src homology-2 domains in insulin signaling in Xenopus oocytes.

    Science.gov (United States)

    Chuang, L M; Hausdorff, S F; Myers, M G; White, M F; Birnbaum, M J; Kahn, C R

    1994-11-04

    Insulin receptor substrate-1 (IRS-1) serves as the major immediate substrate of insulin/insulin-like growth factor (IGF)-1 receptors and following tyrosine phosphorylation binds to specific Src homology-2 (SH2) domain-containing proteins including the p85 subunit of phosphatidylinositol (PI) 3-kinase and GRB2, a molecule believed to link IRS-1 to the Ras pathway. To investigate how these SH2-containing signaling molecules interact to regulate insulin/IGF-1 action, IRS-1, glutathione S-transferase (GST)-SH2 domain fusion proteins and Ras proteins were microinjected into Xenopus oocytes. We found that pleiotropic insulin actions are mediated by IRS-1 through two independent, but convergent, pathways involving PI 3-kinase and GRB2. Thus, microinjection of GST-fusion proteins of either p85 or GRB2 inhibited IRS-1-dependent activation of mitogen-activated protein (MAP) and S6 kinases and oocyte maturation, although only the GST-SH2 of p85 reduced insulin-stimulated PI 3-kinase activation. Co-injection of a dominant negative Ras (S17N) with IRS-1 inhibited insulin-stimulated MAP and S6 kinase activation. Micro-injection of activated [Arg12,Thr59]Ras increased basal MAP and S6 kinase activities and sensitized the oocytes to insulin-stimulated maturation without altering insulin-stimulated PI 3-kinase. The Ras-enhanced oocyte maturation response, but not the elevated basal level of MAP and S6 kinase, was partially blocked by the SH2-p85, but not SH2-GRB2. These data strongly suggest that IRS-1 can mediate many of insulin's actions on cellular enzyme activation and cell cycle progression requires binding and activation of multiple different SH2-domain proteins.

  10. Differential interaction of Apolipoprotein-E isoforms with insulin receptors modulates brain insulin signaling in mutant human amyloid precursor protein transgenic mice.

    Science.gov (United States)

    Chan, Elizabeth S; Chen, Christopher; Cole, Gregory M; Wong, Boon-Seng

    2015-09-08

    It is unclear how human apolipoprotein E4 (ApoE4) increases the risk for Alzheimer's disease (AD). Although Aβ levels can lead to insulin signaling impairment, these experiments were done in the absence of human ApoE. To examine ApoE role, we crossed the human ApoE-targeted replacement mice with mutant human amyloid precursor protein (APP) mice. In 26 week old mice with lower Aβ levels, the expression and phosphorylation of insulin signaling proteins remained comparable among APP, ApoE3xAPP and ApoE4xAPP mouse brains. When the mice aged to 78 weeks, these proteins were markedly reduced in APP and ApoE4xAPP mouse brains. While Aβ can bind to insulin receptor, how ApoE isoforms modulate this interaction remains unknown. Here, we showed that ApoE3 had greater association with insulin receptor as compared to ApoE4, regardless of Aβ42 concentration. In contrast, ApoE4 bound more Aβ42 with increasing peptide levels. Using primary hippocampal neurons, we showed that ApoE3 and ApoE4 neurons are equally sensitive to physiological levels of insulin. However, in the presence of Aβ42, insulin failed to elicit a downstream response only in ApoE4 hippocampal neurons. Taken together, our data show that ApoE genotypes can modulate this Aβ-mediated insulin signaling impairment.

  11. Angiotensin receptor blockade improves cardiac mitochondrial activity in response to an acute glucose load in obese insulin resistant rats

    Directory of Open Access Journals (Sweden)

    Max Thorwald

    2018-04-01

    Full Text Available Hyperglycemia increases the risk of oxidant overproduction in the heart through activation of a multitude of pathways. Oxidation of mitochondrial enzymes may impair their function resulting in accumulation of intermediates and reverse electron transfer, contributing to mitochondrial dysfunction. Furthermore, the renin-angiotensin system (RAS becomes inappropriately activated during metabolic syndrome, increasing oxidant production. To combat excess oxidant production, the transcription factor, nuclear factor erythriod-2- related factor 2 (Nrf2, induces expression of many antioxidant genes. We hypothesized that angiotensin II receptor type 1 (AT1 blockade improves mitochondrial function in response to an acute glucose load via upregulation of Nrf2. To address this hypothesis, an oral glucose challenge was performed in three groups prior to dissection (n = 5–8 animals/group/time point of adult male rats: 1 Long Evans Tokushima Otsuka (LETO; lean strain-control, 2 insulin resistant, obese Otsuka Long Evans Tokushima Fatty (OLETF, and 3 OLETF + angiotensin receptor blocker (ARB; 10 mg olmesartan/kg/d × 6 weeks. Hearts were collected at T0, T60, and T120 minutes post-glucose infusion. ARB increased Nrf2 binding 32% compared to OLETF at T60. Total superoxide dismutase (SOD and catalase (CAT activities were increased 45% and 66% respectively in ARB treated animals compared to OLETF. Mitochondrial enzyme activities of aconitase, complex I, and complex II increased by 135%, 33% and 66%, respectively in ARB compared to OLETF. These data demonstrate the protective effects of AT1 blockade on mitochondrial function during the manifestation of insulin resistance suggesting that the inappropriate activation of AT1 during insulin resistance may impair Nrf2 translocation and subsequent antioxidant activities and mitochondrial function. Keywords: Angiotensin II, Mitochondria, Cardiac, Antioxidant enzymes, TCA cycle

  12. Insulin-like Growth Factor Receptor Inhibitors: Baby or the Bathwater?

    OpenAIRE

    Yee, Douglas

    2012-01-01

    The success of targeted therapies for cancer is undisputed; strong preclinical evidence has resulted in the approval of several new agents for cancer treatment. The type I insulin-like growth factor receptor (IGF1R) appeared to be one of these promising new targets. Substantial population and preclinical data have all pointed toward this pathway as an important regulator of tumor cell biology. Although early results from clinical trials that targeted the IGF1R showed some evidence of response...

  13. Development of gene diagnosis for diabetes and cholecystitis based on gene analysis of CCK-A receptor

    International Nuclear Information System (INIS)

    Kono, Akira

    1999-01-01

    Base sequence analysis of CCKAR gene (a gene of A-type receptor for cholecystokinin) from OLETF rat, a model rat for insulin-independent diabetes was made based on the base sequence of wild CCKAR gene, which had been clarified in the previous year. From the pancreas of OLETF rat, DNA was extracted and transduced into λphage after fragmentation to construct the gene library of OLETF. Then, λphage DNA clone bound with labelled cDNA of CCKAR gene was analyzed and the gene structure was compared with that of the wild gene. It was demonstrated that CCKAR gene of OLETF had a deletion (6800 b.p.) ranging from the promoter region to the Exon 2, suggesting that CCKAR gene is not functional in OLETF rat. The whole sequence of this mutant gene was registered into Japan DNA Bank (D 50610). Then, F 2 offspring rats were obtained through crossing OLETF (female) and F344 (male) and the time course-changes in the blood glucose level after glucose loading were compared among them. The blood glucose level after glucose loading was significantly higher in the homo-mutant F 2 (CCKAR,-/-) as well as the parent OLETF rat than hetero-mutant F 2 (CCKARm-/+) or the wild rat (CCKAR,+/+). This suggests that CCKAR gene might be involved in the control of blood glucose level and an alteration of the expression level or the functions of CCKAR gene might affect the blood glucose level. (M.N.)

  14. The Implication of the Brain Insulin Receptor in Late Onset Alzheimer’s Disease Dementia

    Directory of Open Access Journals (Sweden)

    Jaume Folch

    2018-01-01

    Full Text Available Alzheimer’s disease (AD is progressive neurodegenerative disorder characterized by brain accumulation of the amyloid β peptide (Aβ, which form senile plaques, neurofibrillary tangles (NFT and, eventually, neurodegeneration and cognitive impairment. Interestingly, epidemiological studies have described a relationship between type 2 diabetes mellitus (T2DM and this pathology, being one of the risk factors for the development of AD pathogenesis. Information as it is, it would point out that, impairment in insulin signalling and glucose metabolism, in central as well as peripheral systems, would be one of the reasons for the cognitive decline. Brain insulin resistance, also known as Type 3 diabetes, leads to the increase of Aβ production and TAU phosphorylation, mitochondrial dysfunction, oxidative stress, protein misfolding, and cognitive impairment, which are all hallmarks of AD. Moreover, given the complexity of interlocking mechanisms found in late onset AD (LOAD pathogenesis, more data is being obtained. Recent evidence showed that Aβ42 generated in the brain would impact negatively on the hypothalamus, accelerating the “peripheral” symptomatology of AD. In this situation, Aβ42 production would induce hypothalamic dysfunction that would favour peripheral hyperglycaemia due to down regulation of the liver insulin receptor. The objective of this review is to discuss the existing evidence supporting the concept that brain insulin resistance and altered glucose metabolism play an important role in pathogenesis of LOAD. Furthermore, we discuss AD treatment approaches targeting insulin signalling using anti-diabetic drugs and mTOR inhibitors.

  15. Novel Zn2+ Modulated GPR39 Receptor Agonists Do Not Drive Acute Insulin Secretion in Rodents.

    Directory of Open Access Journals (Sweden)

    Ola Fjellström

    Full Text Available Type 2 diabetes (T2D occurs when there is insufficient insulin release to control blood glucose, due to insulin resistance and impaired β-cell function. The GPR39 receptor is expressed in metabolic tissues including pancreatic β-cells and has been proposed as a T2D target. Specifically, GPR39 agonists might improve β-cell function leading to more adequate and sustained insulin release and glucose control. The present study aimed to test the hypothesis that GPR39 agonism would improve glucose stimulated insulin secretion in vivo. A high throughput screen, followed by a medicinal chemistry program, identified three novel potent Zn2+ modulated GPR39 agonists. These agonists were evaluated in acute rodent glucose tolerance tests. The results showed a lack of glucose lowering and insulinotropic effects not only in lean mice, but also in diet-induced obese (DIO mice and Zucker fatty rats. It is concluded that Zn2+ modulated GPR39 agonists do not acutely stimulate insulin release in rodents.

  16. The Proton-Activated Receptor GPR4 Modulates Glucose Homeostasis by Increasing Insulin Sensitivity

    Directory of Open Access Journals (Sweden)

    Luca Giudici

    2013-11-01

    Full Text Available Background: The proton-activated G protein-coupled receptor GPR4 is expressed in many tissues including white adipose tissue. GPR4 is activated by extracellular protons in the physiological pH range (i.e. pH 7.7 - 6.8 and is coupled to the production of cAMP. Methods: We examined mice lacking GPR4 and examined glucose tolerance and insulin sensitivity in young and aged mice as well as in mice fed with a high fat diet. Expression profiles of pro- and anti-inflammatory cytokines in white adipose tissue, liver and skeletal muscle was assessed. Results: Here we show that mice lacking GPR4 have an improved intraperitoneal glucose tolerance test and increased insulin sensitivity. Insulin levels were comparable but leptin levels were increased in GPR4 KO mice. Gpr4-/- showed altered expression of PPARα, IL-6, IL-10, TNFα, and TGF-1β in skeletal muscle, white adipose tissue, and liver. High fat diet abolished the differences in glucose tolerance and insulin sensitivity between Gpr4+/+ and Gpr4-/- mice. In contrast, in aged mice (12 months old, the positive effect of GPR4 deficiency on glucose tolerance and insulin sensitivity was maintained. Liver and adipose tissue showed no major differences in the mRNA expression of pro- and anti-inflammatory factors between aged mice of both genotypes. Conclusion: Thus, GPR4 deficiency improves glucose tolerance and insulin sensitivity. The effect may involve an altered balance between pro- and anti-inflammatory factors in insulin target tissues.

  17. Insulin

    Science.gov (United States)

    ... For Consumers Home For Consumers Consumer Information by Audience For Women Women's Health Topics Insulin Share Tweet ... I start having side effects? What is my target blood sugar level? How often should I check ...

  18. 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

  19. Effect of adrenomedullin gene delivery on insulin resistance in type 2 diabetic rats

    Directory of Open Access Journals (Sweden)

    Hoda Y. Henein

    2011-01-01

    Full Text Available Type 2 diabetes mellitus is one of the common metabolic disorders that ultimately afflicts large number of individuals. Adrenomedullin (AM is a potent vasodilator peptide; previous studies reported development of insulin resistance in aged AM deficient mice. In this study, we employed a gene delivery approach to explore its potential role in insulin resistance. Four groups were included: control, diabetic, non-diabetic injected with the AM gene and diabetic injected with the AM gene. One week following gene delivery, serum glucose, insulin, triglycerides, leptin, adiponectin and corticosterone were measured as well as the insulin resistance index (HOMA-IR. Soleus muscle glucose uptake and RT-PCR of both AM and glucose transporter-4 (GLUT 4 gene expressions were assessed. A single tail vein injection of adrenomedullin gene in type 2 diabetic rats improved skeletal muscle insulin responsiveness with significant improvement of soleus muscle glucose uptake, HOMA-IR, serum glucose, insulin and triglycerides and significant increase in muscle GLUT 4 gene expression (P < 0.05 compared with the non-injected diabetic rats. The beneficial effects of AM gene delivery were accompanied by a significant increase in the serum level of adiponectin (2.95 ± 0.09 versus 2.33 ± 0.17 μg/ml in the non-injected diabetic group as well as a significant decrease in leptin and corticosterone levels (7.51 ± 0.51 and 262.88 ± 10.34 versus 10.63 ± 1.4 and 275.86 ± 11.19 ng/ml respectively in the non-injected diabetic group. The conclusion of the study is that AM gene delivery can improve insulin resistance and may have significant therapeutic applications in type 2 diabetes mellitus.

  20. Widespread ectopic expression of olfactory receptor genes

    Directory of Open Access Journals (Sweden)

    Yanai Itai

    2006-05-01

    Full Text Available Abstract Background Olfactory receptors (ORs are the largest gene family in the human genome. Although they are expected to be expressed specifically in olfactory tissues, some ectopic expression has been reported, with special emphasis on sperm and testis. The present study systematically explores the expression patterns of OR genes in a large number of tissues and assesses the potential functional implication of such ectopic expression. Results We analyzed the expression of hundreds of human and mouse OR transcripts, via EST and microarray data, in several dozens of human and mouse tissues. Different tissues had specific, relatively small OR gene subsets which had particularly high expression levels. In testis, average expression was not particularly high, and very few highly expressed genes were found, none corresponding to ORs previously implicated in sperm chemotaxis. Higher expression levels were more common for genes with a non-OR genomic neighbor. Importantly, no correlation in expression levels was detected for human-mouse orthologous pairs. Also, no significant difference in expression levels was seen between intact and pseudogenized ORs, except for the pseudogenes of subfamily 7E which has undergone a human-specific expansion. Conclusion The OR superfamily as a whole, show widespread, locus-dependent and heterogeneous expression, in agreement with a neutral or near neutral evolutionary model for transcription control. These results cannot reject the possibility that small OR subsets might play functional roles in different tissues, however considerable care should be exerted when offering a functional interpretation for ectopic OR expression based only on transcription information.

  1. Biodistribution and receptor imaging studies of insulin labelled with radioiodine in mice bearing H22 hepatocellular cacinoma

    International Nuclear Information System (INIS)

    Tang Gongshun; Kuang Anren; Liang Zenlu

    2004-01-01

    Objectives: It has been demonstrated that insulin receptor of hepatocellular carcinoma cells is overexpression. The biodistribution of 125I-insulin and receptor imaging studies of 131I-insulin in mice bearing solid liver tumor comprised of hepatic carcinoma H22 cells were performed to develop insulin as a carder of radioiodine. Methods: 1 )Insulin was radiolabeled with iodine-125 or iodine-131 using a Chloramines T method. Twenty mice bearing tumor were divided into 4 groups (n = 5 each) randomly. They were killed at 5, 15, 30, 60 min after 125I-insulin administered intravenously. The percentage of injected dose of 125I-insulin per gram of tissue(%ID/gdis) in mice bearing tumor were determined. 2) Another ten mice bearing tumor were selected to be as a inhibition group. They received cold insulin 2 mg intravenously 2 min ahead of administration of 125I-insulin and they were killed at 30 min (n=5) and 60 rain (n=5) randomly post 125I-insulin injection. The %ID/ginh and the inhibited rates[(%ID/gdis-%iD/ginh) %ID/gdis 100%] were obtained. 3) One tumor-mouse received 7.4 Mbq 13II-insulin intravenously, another received cold insulin 2 mg injection before 13II-insulin injection. Whole body images were carded out and the radioactivity ratios of tumor/normal were accounted at 60 min. Results: 1) The radiochemical purities of 125I-insulin and 13II-insulin were 96.7%-98.9%. The tumors uptake of the 125I-insulin increased gradually, its peak (%ID/gdis) was 3.44% 0.42% at 30 min, when the normal tissues uptake decreased sharply post-injection. The radioactivity ratio of the tumor/blood and tumor/muscle reached to 1.44 and 3.62 respectively at 60 min. 2)The tumor-inhibition rate was 32.07% at 30 min and 37.42% at 60 min. 3) A high radioactivity accumulation in tumor region could be seen in the mouse at 60 min post 131I-insulin injection. The radioactivity ratio of the tumor/normal tissue was 2.13 and it declined to 1.37 after received insulin 2 mg intervention. Conclusions

  2. Nuclear orphan receptor TLX affects gene expression, proliferation and cell apoptosis in beta cells

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Xiaoli; Xiong, Xiaokan; Dai, Zhe; Deng, Haohua; Sun, Li; Hu, Xuemei; Zhou, Feng; Xu, Yancheng, E-mail: oxyccc@163.com

    2015-12-04

    Nuclear orphan receptor TLX is an essential regulator of the growth of neural stem cells. However, its exact function in pancreatic islet cells is still unknown. In the present study, gene expression profiling analysis revealed that overexpression of TLX in beta cell line MIN6 causes suppression of 176 genes and upregulation of 49 genes, including a cadre of cell cycle, cell proliferation and cell death control genes, such as Btg2, Ddit3 and Gadd45a. We next examined the effects of TLX overexpression on proliferation, apoptosis and insulin secretion in MIN6 cells. Proliferation analysis using EdU assay showed that overexpression of TLX increased percentage of EdU-positive cells. Cell cycle and apoptosis analysis revealed that overexpression of TLX in MIN6 cells resulted in higher percentage of cells exiting G1 into S-phase, and a 58.8% decrease of cell apoptosis induced by 0.5 mM palmitate. Moreover, TLX overexpression did not cause impairment of insulin secretion. Together, we conclude that TLX is among factors capable of controlling beta cell proliferation and survival, which may serve as a target for the development of novel therapies for diabetes. - Highlights: • TLX overexpression in MIN6 cell causes significant expression changes of 225 genes. • TLX overexpression promotes MIN6 cell proliferation and decreases cell apoptosis. • TLX overexpression does not cause impairment of insulin secretion.

  3. Nuclear orphan receptor TLX affects gene expression, proliferation and cell apoptosis in beta cells

    International Nuclear Information System (INIS)

    Shi, Xiaoli; Xiong, Xiaokan; Dai, Zhe; Deng, Haohua; Sun, Li; Hu, Xuemei; Zhou, Feng; Xu, Yancheng

    2015-01-01

    Nuclear orphan receptor TLX is an essential regulator of the growth of neural stem cells. However, its exact function in pancreatic islet cells is still unknown. In the present study, gene expression profiling analysis revealed that overexpression of TLX in beta cell line MIN6 causes suppression of 176 genes and upregulation of 49 genes, including a cadre of cell cycle, cell proliferation and cell death control genes, such as Btg2, Ddit3 and Gadd45a. We next examined the effects of TLX overexpression on proliferation, apoptosis and insulin secretion in MIN6 cells. Proliferation analysis using EdU assay showed that overexpression of TLX increased percentage of EdU-positive cells. Cell cycle and apoptosis analysis revealed that overexpression of TLX in MIN6 cells resulted in higher percentage of cells exiting G1 into S-phase, and a 58.8% decrease of cell apoptosis induced by 0.5 mM palmitate. Moreover, TLX overexpression did not cause impairment of insulin secretion. Together, we conclude that TLX is among factors capable of controlling beta cell proliferation and survival, which may serve as a target for the development of novel therapies for diabetes. - Highlights: • TLX overexpression in MIN6 cell causes significant expression changes of 225 genes. • TLX overexpression promotes MIN6 cell proliferation and decreases cell apoptosis. • TLX overexpression does not cause impairment of insulin secretion.

  4. Insulin and 20-hydroxyecdysone action in Bombyx mori: Glycogen content and expression pattern of insulin and ecdysone receptors in fat body.

    Science.gov (United States)

    Keshan, Bela; Thounaojam, Bembem; Kh, Sanathoibi D

    2017-01-15

    Insulin and ecdysone signaling play a critical role on the growth and development of insects including Bombyx mori. Our previous study showed that Bombyx larvae reached critical weight for metamorphosis between day 3.5 and 4 of the fifth larval instar. The present study showed that the effect of insulin on the accumulation of glycogen in fat body of Bombyx larvae depends on the critical growth period. When larvae are in active growth period (before reaching critical weight), insulin caused increased accumulation of glycogen, while its treatment in larvae at terminal growth period (after critical period) resulted in an increased mobilization of glycogen. During terminal growth period, insulin and 20-hydroxyecdysone (20E) showed an antagonistic effect on the accumulation of fat body glycogen in fed, food deprived and decapitated larvae as well as in isolated abdomens. Insulin treatment decreased the glycogen content, whereas, 20E increased it. Food deprivation and decapitation caused an increase in the transcript levels of insulin receptor (InR) and this increase in InR expression might be attributed to a decrease in synthesis/secretion of insulin-like peptides, as insulin treatment in these larvae showed a down-regulation in InR expression. However, insulin showed an up-regulation in InR in isolated abdomens and it suggests that in food deprived and decapitated larvae, the exogenous insulin may interact with some head and/or thoracic factors in modulating the expression of InR. Moreover, in fed larvae, insulin-mediated increase in InR expression indicates that its regulation by insulin-like peptides also depends on the nutritional status of the larvae. The treatment of 20E in fed larvae showed an antagonistic effect on the transcript levels since a down-regulation in InR expression was observed. 20E treatment also led to a decreased expression of InR in food deprived and decapitated larvae as well as in isolated abdomens. Insulin and 20E also modulated the

  5. Development of receptors for insulin and insulin-like growth factor-I in head and brain of chick embryos: Autoradiographic localization

    International Nuclear Information System (INIS)

    Bassas, L.; Girbau, M.; Lesniak, M.A.; Roth, J.; de Pablo, F.

    1989-01-01

    In whole brain of chick embryos insulin receptors are highest at the end of embryonic development, while insulin-like growth factor-I (IGF-I) receptors dominate in the early stages. These studies provided evidence for developmental regulation of both types of receptors, but they did not provide information on possible differences between brain regions at each developmental stage or within one region at different embryonic ages. We have now localized the specific binding of [125I]insulin and [125I]IGF-I in sections of head and brain using autoradiography and computer-assisted densitometric analysis. Embryos have been studied from the latter part of organogenesis (days 6 and 12) through late development (day 18, i.e. 3 days before hatching), and the binding patterns have been compared with those in the adult brain. At all ages the binding of both ligands was to discrete anatomical regions. Interestingly, while in late embryos and adult brain the patterns of [125I]insulin and [125I] IGF-I binding were quite distinct, in young embryos both ligands showed very similar localization of binding. In young embryos the retina and lateral wall of the growing encephalic vesicles had the highest binding of both [125I]insulin and [125I]IGF-I. In older embryos, as in the adult brain, insulin binding was high in the paleostriatum augmentatum and molecular layer of the cerebellum, while IGF-I binding was prominent in the hippocampus and neostriatum. The mapping of receptors in a vertebrate embryo model from early prenatal development until adulthood predicts great overlap in any possible function of insulin and IGF-I in brain development, while it anticipates differential localized actions of the peptides in the mature brain

  6. Insulin-Independent GABAA Receptor-Mediated Response in the Barrel Cortex of Mice with Impaired Met Activity.

    Science.gov (United States)

    Lo, Fu-Sun; Erzurumlu, Reha S; Powell, Elizabeth M

    2016-03-30

    Autism spectrum disorder (ASD) is a neurodevelopmental disorder caused by genetic variants, susceptibility alleles, and environmental perturbations. The autism associated geneMETtyrosine kinase has been implicated in many behavioral domains and endophenotypes of autism, including abnormal neural signaling in human sensory cortex. We investigated somatosensory thalamocortical synaptic communication in mice deficient in Met activity in cortical excitatory neurons to gain insights into aberrant somatosensation characteristic of ASD. The ratio of excitation to inhibition is dramatically increased due to decreased postsynaptic GABAAreceptor-mediated inhibition in the trigeminal thalamocortical pathway of mice lacking active Met in the cerebral cortex. Furthermore, in contrast to wild-type mice, insulin failed to increase GABAAreceptor-mediated response in the barrel cortex of mice with compromised Met signaling. Thus, lacking insulin effects may be a risk factor in ASD pathogenesis. A proposed common cause of neurodevelopmental disorders is an imbalance in excitatory neural transmission, provided by the glutamatergic neurons, and the inhibitory signals from the GABAergic interneurons. Many genes associated with autism spectrum disorders impair synaptic transmission in the expected cell type. Previously, inactivation of the autism-associated Met tyrosine kinase receptor in GABAergic interneurons led to decreased inhibition. In thus report, decreased Met signaling in glutamatergic neurons had no effect on excitation, but decimated inhibition. Further experiments indicate that loss of Met activity downregulates GABAAreceptors on glutamatergic neurons in an insulin independent manner. These data provide a new mechanism for the loss of inhibition and subsequent abnormal excitation/inhibition balance and potential molecular candidates for treatment or prevention. Copyright © 2016 the authors 0270-6474/16/363691-07$15.00/0.

  7. 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.

  8. Insulin, Central Dopamine D2 Receptors, and Monetary Reward Discounting in Obesity.

    Science.gov (United States)

    Eisenstein, Sarah A; Gredysa, Danuta M; Antenor-Dorsey, Jo Ann; Green, Leonard; Arbeláez, Ana Maria; Koller, Jonathan M; Black, Kevin J; Perlmutter, Joel S; Moerlein, Stephen M; Hershey, Tamara

    2015-01-01

    Animal research finds that insulin regulates dopamine signaling and reward behavior, but similar research in humans is lacking. We investigated whether individual differences in body mass index, percent body fat, pancreatic β-cell function, and dopamine D2 receptor binding were related to reward discounting in obese and non-obese adult men and women. Obese (n = 27; body mass index>30) and non-obese (n = 20; body mass indexmonetary rewards relative to immediate, certain smaller monetary rewards was measured using delayed and probabilistic reward discounting tasks. Positron emission tomography using a non-displaceable D2-specific radioligand, [11C](N-methyl)benperidol quantified striatal D2 receptor binding. Groups differed in body mass index, percent body fat, and disposition index, but not in striatal D2 receptor specific binding or reward discounting. Higher percent body fat in non-obese women related to preference for a smaller, certain reward over a larger, less likely one (greater probabilistic discounting). Lower β-cell function in the total sample and lower insulin sensitivity in obese related to stronger preference for an immediate and smaller monetary reward over delayed receipt of a larger one (greater delay discounting). In obese adults, higher striatal D2 receptor binding related to greater delay discounting. Interestingly, striatal D2 receptor binding was not significantly related to body mass index, percent body fat, or β-cell function in either group. Our findings indicate that individual differences in percent body fat, β-cell function, and striatal D2 receptor binding may each contribute to altered reward discounting behavior in non-obese and obese individuals. These results raise interesting questions about whether and how striatal D2 receptor binding and metabolic factors, including β-cell function, interact to affect reward discounting in humans.

  9. Leu72Met and Other Intronic Polymorphisms in the and Genes Are Not Associated with Type 2 Diabetes Mellitus, Insulin Resistance, or Serum Ghrelin Levels in a Saudi Population

    OpenAIRE

    Faris Elbahi Joatar; Ali Ahmed Al Qarni; Muhalab E. Ali; Abdulaziz Al Masaud; Abdirashid M. Shire; Nagalla Das; Khalid Gumaa; Hayder A. Giha

    2017-01-01

    Background Ghrelin (GHRL), a gastric peptide encoded by the GHRL gene, is known to be involved in energy homeostasis via its G protein receptor, encoded by the growth hormone secretagogue receptor (GHSR) gene. Some studies have shown associations between plasma GHRL levels and GHRL single-nucleotide polymorphisms (SNPs), namely the Leu72Met polymorphism (rs696217 TG), with type 2 diabetes mellitus (T2DM) and insulin resistance (IR), while others have not. The controversies in these associatio...

  10. FGF receptor genes and breast cancer susceptibility

    DEFF Research Database (Denmark)

    Agarwal, D; Pineda, S; Michailidou, K

    2014-01-01

    Background:Breast cancer is one of the most common malignancies in women. Genome-wide association studies have identified FGFR2 as a breast cancer susceptibility gene. Common variation in other fibroblast growth factor (FGF) receptors might also modify risk. We tested this hypothesis by studying...... genotyped single-nucleotide polymorphisms (SNPs) and imputed SNPs in FGFR1, FGFR3, FGFR4 and FGFRL1 in the Breast Cancer Association Consortium.Methods:Data were combined from 49 studies, including 53 835 cases and 50 156 controls, of which 89 050 (46 450 cases and 42 600 controls) were of European ancestry......, 12 893 (6269 cases and 6624 controls) of Asian and 2048 (1116 cases and 932 controls) of African ancestry. Associations with risk of breast cancer, overall and by disease sub-type, were assessed using unconditional logistic regression.Results:Little evidence of association with breast cancer risk...

  11. Reduction of lns-1 gene expression and tissue insulin levels in n5-STZ rats

    Directory of Open Access Journals (Sweden)

    Belinda Vargas Guerrero

    2013-01-01

    Full Text Available Objective: The high global incidence of type 2 diabetes has challenged researchers to establish animal models that resemble the chronic stage observed in type 2 diabetes patients. One such model is induced by neonatal streptozotocin (n-STZ administration to rat pups at 0, 2, or 5 days after birth. In this study, we assessed lns-1 gene expression and tissue insulin levels as well as serum concentration of glucose and insulin, insulin resistance, and histological changes of the islets of Langerhans in n5-STZ rats after 20-weeks post-induction. Methods: Wistar rat pups were randomly distributed into a control group and a streptozotocin-induced group. Experimental induction involved a single intraperitoneal injection of streptozotocin (150 mg/kg into neonates at five days after birth. Results: At 20 weeks post-induction, streptozotocin-induced rats exhibited increased serum glucose levels, reduced serum insulin levels, impaired glucose metabolism and insulin resistance compared to control rats. Histologically, streptozotocin-induced rats exhibited atrophic islets, vacuolization, and significantly fewer insulin-positive cells. lns-1 gene expression was significantly decreased in n5-STZ rats in comparison to the control group. Conclusion: Our findings support that the n5-STZ model 20 weeks post-induction represents an appropriate experimental tool to study T2D and to evaluate novel therapeutic agents and targets that involve insulin gene expression and secretion, as well as complications caused by chronic diabetes.

  12. Insulin receptor binding and tyrosine kinase activity in skeletal muscle from normal pregnant women and women with gestational diabetes

    DEFF Research Database (Denmark)

    Damm, P.; Handberg, A.; Kühl, C.

    1993-01-01

    OBJECTIVE: To ascertain whether the decreased glucose tolerance and insulin resistance found in normal and gestational diabetic pregnancy might be associated with changes in insulin receptor function. METHODS: Eight nonpregnant healthy women (nonpregnant controls), eight healthy pregnant women...... (pregnant controls), and eight women with gestational diabetes were investigated. All were non-obese. Muscle biopsies were obtained from the vastus lateralis muscle, and insulin binding and tyrosine kinase activities in partially purified skeletal muscle insulin receptors were studied. The pregnant controls...... with gestational diabetes compared to nonpregnant controls (P pregnant women did not differ from the other two groups. Postpartum, no differences in insulin binding were found between the groups. Basal and maximal tyrosine kinase activities toward the exogenous substrate poly(Glu4Tyr1) were...

  13. Conjugated Linoleic Acids Mediate Insulin Release through Islet G Protein-coupled Receptor FFA1/GPR40

    DEFF Research Database (Denmark)

    Schmidt, Johannes; Liebscher, Kathrin; Merten, Nicole

    2011-01-01

    of insulin resistance and the risk of developing diabetes. However, the mechanisms accounting for the effects of CLAs on glucose homeostasis are incompletely understood. Herein we provide evidence that CLAs specifically activate the cell surface receptor FFA1, an emerging therapeutic target to treat type 2...... found to activate FFA1 in vitro at concentrations sufficient to also account for FFA1 activation in vivo. Each CLA isomer markedly increased glucose-stimulated insulin secretion in insulin-producing INS-1E cells that endogenously express FFA1 and in primary pancreatic β-cells of wild type but not FFA1......(-/-) knock-out mice. Our findings establish a clear mechanistic link between CLAs and insulin production and identify the cell surface receptor FFA1 as a molecular target for CLAs, explaining their acute stimulatory effects on insulin secretion in vivo. CLAs are also revealed as insulinotropic components...

  14. Research progress of the bitter taste receptor genes in primates.

    Science.gov (United States)

    Feng, Ping; Luo, Rui-Jian

    2018-02-20

    Among the five basic tastes (umami, sweet, bitter, salty and sour), the perception of bitterness is believed to protect animals from digesting toxic and harmful substances, thus it is vital for animal survival. The taste of bitterness is triggered by the interaction between bitter substances and bitter taste receptors, which are encoded by Tas2rs. The gene numbers vary largely across species to meet different demands. So far, several ligands of bitter receptors have been identified in primates. They also discovered that the selective pressure of certain bitter taste receptor genes vary across taxa, genes or even different functional regions of the gene. In this review, we summarize the research progress of bitter taste receptor genes in primates by introducing the functional diversity of bitter receptors, the specific interaction between bitter taste receptors and ligands, the relationship between the evolutionary pattern of bitter taste receptors and diets, and the adaptive evolution of bitter taste receptor genes. We aim to provide a reference for further research on bitter receptor genes in primates.

  15. The LDL Receptor-Related Protein 1: At the Crossroads of Lipoprotein Metabolism and Insulin Signaling

    Directory of Open Access Journals (Sweden)

    Dianaly T. Au

    2017-01-01

    Full Text Available The metabolic syndrome is an escalating worldwide public health concern. Defined by a combination of physiological, metabolic, and biochemical factors, the metabolic syndrome is used as a clinical guideline to identify individuals with a higher risk for type 2 diabetes and cardiovascular disease. Although risk factors for type 2 diabetes and cardiovascular disease have been known for decades, the molecular mechanisms involved in the pathophysiology of these diseases and their interrelationship remain unclear. The LDL receptor-related protein 1 (LRP1 is a large endocytic and signaling receptor that is widely expressed in several tissues. As a member of the LDL receptor family, LRP1 is involved in the clearance of chylomicron remnants from the circulation and has been demonstrated to be atheroprotective. Recently, studies have shown that LRP1 is involved in insulin receptor trafficking and regulation and glucose metabolism. This review summarizes the role of tissue-specific LRP1 in insulin signaling and its potential role as a link between lipoprotein and glucose metabolism in diabetes.

  16. Evaluation of organ-specific glucose metabolism by 18F-FDG in insulin receptor substrate-1 (IRS-1) knockout mice as a model of insulin resistance

    International Nuclear Information System (INIS)

    Cheng, Chao; Nakamura, Akinobu; Minamimoto, Ryogo; Shinoda, Kazuaki; Tateishi, Ukihide; Terauchi, Yasuo; Inoue, Tomio; Goto, Atsuhi; Kadowaki, Takashi

    2011-01-01

    Insulin resistance (IR) is a physiological condition in which the body produces insulin but does not result in a sufficient biological effect. Insulin resistance is usually asymptomatic but is associated with health problems and is a factor in the metabolic syndrome. The aim of the present study is to clarify organ-specific insulin resistance in normal daily conditions using [ 18 F]-2-fluoro-2-deoxy-D-glucose ([ 18 F]-FDG). The biodistribution of [ 18 F]-FDG was examined in insulin receptor substrate-1 (IRS-1) knockout mice, an animal model of skeletal muscle insulin resistance, and C57BL/6J (wild-type) mice with and without insulin loading. Mice received 0.5 MBq of [ 18 F]-FDG injected into the tail vein, immediately followed by nothing (control cohorts) or an intraperitoneal injection of 1.5 mU/g body weight of human insulin as an insulin loading test. Blood glucose concentrations for all of the experimental animals were assessed at 0, 20, 40, and 60 min post-injection. The mice were subsequently killed, and tissue was collected for evaluation of [ 18 F]-FDG biodistribution. The radioactivity of each organ was measured using a gamma counter. In the absence of insulin, the blood glucose concentrations of wild-type mice (132±26 mg/dl) and IRS-1 knockout mice (134±18 mg/dl) were not significantly different. Blood glucose concentrations decreased following insulin administration, with lower concentrations in wild-type mice than in knockout mice at 20, 40, and 60 min. A statistically significant difference in [ 18 F]-FDG uptake between wild-type mice and IRS-1 knockout mice was confirmed in the heart, abdominal muscle, and femoral muscle. With insulin loading, [ 18 F]-FDG uptake in the heart, back muscle, and abdominal muscle was significantly increased compared to without insulin loading in both wild-type mice and knockout mice. Our results showed that IR significantly affected [ 18 F]-FDG uptake in the heart in normal daily conditions. IR was associated with

  17. Polymorphism in leptin receptor gene was associated with obesity in ...

    African Journals Online (AJOL)

    The mutation in leptin receptor (LEPR) gene causes splicing abnormality that resulted in truncated receptor, aberrant signal transduction, leptin resistance, and obesity. This study aims to determine the association of LEPR gene polymorphisms, rs1137100 and rs1137101, on phenotype and leptin level between obese and ...

  18. Cannabinoid 2 Receptor Agonist Improves Systemic Sensitivity to Insulin in High-Fat Diet/Streptozotocin-Induced Diabetic Mice

    Directory of Open Access Journals (Sweden)

    Xiuyuan Zhang

    2016-12-01

    Full Text Available Background/Aims: The endocannabinoid signalling (ECS system has been known to regulate glucose homeostasis. Previous studies have suggested that the cannabinoid 2 (CB2 receptor may play a regulatory role on insulin secretion, immune modulation and insulin resistance. Given that diabetes and insulin resistance are attributable to elevated inflammatory tone, we investigated the role of CB2 receptor on glucose tolerance and insulin sensitivity in high-fat diet (HFD/streptozotocin (STZ-induced mice. Methods: Diabetes was induced in male ICR mice by HFD/STZ and exposed to a CB2 receptor agonist, SER601, for 2- or 4-weeks via subcutaneous implantation of osmotic minipumps. Glucose and insulin tolerance tests were performed at the end of treatment. Islets were isolated for assessment of β-cell function. Pancreases and skeletal muscles were also obtained for histological analyses. Results: Despite a lack of impact on glucose tolerance, substantial improvement on insulin sensitivity was observed in SER601-treated mice, which could partly be attributed to improved islet β-cell function, shown as increased glucose-induced insulin secretion and insulin content. No changes on islet macrophage infiltration or skeletal muscle fat deposition were detectable from SER601-treated mice. However, a major decrease in body weight was recorded at the end of 4-week SER601 exposure, accompanied by a lack of epididymal adipose mass in SER601-treated mice. Conclusion: Our data suggest a lipolytic role of SER601 in HFD/STZ-induced diabetic mice, which results in significant improvement of systemic insulin sensitivity. Thus, the CB2 receptor may be considered a promising target for therapeutic development against insulin resistance and obesity-related diabetes.

  19. Maternal Pre-Gravid Obesity Changes Gene Expression Profiles Towards Greater Inflammation and Reduced Insulin Sensitivity in Umbilical Cord

    Science.gov (United States)

    Thakali, Keshari M.; Saben, Jessica; Faske, Jennifer B.; Lindsey, Forrest; Gomez-Acevedo, Horacio; Lowery, Curtis L.; Badger, Thomas M.; Andres, Aline; Shankar, Kartik

    2014-01-01

    Background Maternal obesity is associated with unfavorable outcomes, which may be reflected in the as yet undiscovered gene expression profiles of the umbilical cord (UC). Methods UCs from 12 lean (pre-gravid BMI obese (OW/OB, pre-gravid BMI ≥25) women without gestational diabetes were collected for gene expression analysis using Human Primeview microarrays (Affymetrix). Metabolic parameters were assayed in mother’s plasma and cord blood. Results Although offspring birth weight and adiposity (at 2-wk) did not differ between groups, expression of 232 transcripts was affected in UC from OW/OB compared to those of lean mothers. GSEA analysis revealed an up-regulation of genes related to metabolism, stimulus and defense response and inhibitory to insulin signaling in the OW/OB group. We confirmed that EGR1, periostin, and FOSB mRNA expression was induced in UCs from OW/OB moms, while endothelin receptor B, KFL10, PEG3 and EGLN3 expression was decreased. Messenger RNA expression of EGR1, FOSB, MEST and SOCS1 were positively correlated (pmaternal obesity and changes in UC gene expression profiles favoring inflammation and insulin resistance, potentially predisposing infants to develop metabolic dysfunction later on in life. PMID:24819376

  20. Type-I Insulin-Like Growth Factor Receptor (IGF1R)-Estrogen Receptor (ER) Crosstalk Contributes to Antiestrogen Therapy Resistance in Breast Cancer Cells

    Science.gov (United States)

    2013-02-01

    vitro have downregulated J GF1R making antibodies directed agai nst th is receptor ineffective. Inhlbition of IH may be necessary to manage ...monoclonal antibody to insulin-like growth factor receptor 1. J Clin Oncol 2009;27:580Q-7. 31. Drury s. Detre s. Leary A, Salter J, Reis-Filho J

  1. Insulin receptor in mouse neuroblastoma cell line N18TG2: binding properties and visualization with colloidal gold.

    Science.gov (United States)

    Sartori, C; Stefanini, S; Bernardo, A; Augusti-Tocco, G

    1992-08-01

    Insulin function in the nervous system is still poorly understood. Possible roles as a neuromodulator and as a growth factor have been proposed (Baskin et al., 1987, Ann. Rev. Physiol. 49, 335-347). Stable cell lines may provide an appropriate experimental system for the analysis of insulin action on the various cellular components of the central nervous system. We report here a study to investigate the presence and the properties of insulin specific binding sites in the murine neuroblastoma line, N18TG2, together with insulin action on cell growth and metabolism. Also, receptor internalization has been studied. Binding experiments, carried out in standard conditions at 20 degrees C, enabled us to demonstrate that these cells bind insulin in a specific manner, thus confirming previous findings on other cell lines. Saturation curves showed the presence of two binding sites with Kd 0.3 and 9.7 nM. Competition experiments with porcine and bovine insulin showed an IC50 of 1 and 10 nM, respectively. Competition did not occur in the presence of the unrelated hormones ACTH and FSH. Dissociation experiments indicated the existence of an internalization process of the ligand-receptor complex; this was confirmed by an ultrastructural study using gold conjugated insulin. As far as the insulin action in N18TG2 cells is concerned, physiological concentrations stimulate cell proliferation, whereas no stimulation of glucose uptake was observed, indicating that insulin action in these cells is not mediated by general metabolic effects. On the basis of these data, N18TG2 line appears to be a very suitable model for further studies of the neuronal type insulin receptors, and possibly insulin specific action on the nervous system.

  2. Induction of human adiponectin gene transcription by telmisartan, angiotensin receptor blocker, independently on PPAR-γ activation

    International Nuclear Information System (INIS)

    Moriuchi, Akie; Yamasaki, Hironori; Shimamura, Mika; Kita, Atsushi; Kuwahara, Hironaga; Fujishima, Keiichiro; Satoh, Tsuyoshi; Fukushima, Keiko; Fukushima, Tetsuya; Hayakawa, Takao; Mizuguchi, Hiroyuki; Nagayama, Yuji; Abiru, Norio; Kawasaki, Eiji; Eguchi, Katsumi

    2007-01-01

    Adiponectin, an adipose tissue-specific plasma protein, has been shown to ameliorate insulin resistance and inhibit the process of atherosclerosis. Recently, several reports have stated that angiotensin type 1 receptor blockers (ARBs), increase adiponectin plasma level, and ameliorate insulin resistance. Telmisartan, a subclass of ARBs, has been shown to be a partial agonist of the peroxisome proliferator-activated receptor (PPAR)-γ, and to increase the plasma adiponectin level. However, the transcriptional regulation of the human adiponectin gene by telmisartan has not been determined yet. To elucidate the effect of telmisartan on adiponectin, the stimulatory regulation of human adiponectin gene by telmisartan was investigated in 3T3-L1 adipocytes, utilizing adenovirus-mediated luciferase reporter gene-transferring technique. This study indicates that telmisartan may stimulate adiponectin transcription independent of PPAR-γ

  3. Characterization of insulin-like growth factor I and insulin receptors on cultured bovine adrenal fasciculata cells. Role of these peptides on adrenal cell function

    International Nuclear Information System (INIS)

    Penhoat, A.; Chatelain, P.G.; Jaillard, C.; Saez, J.M.

    1988-01-01

    We have characterized insulin-like growth factor I (IGF-I) and insulin receptors in cultured bovine adrenal cells by binding and cross-linking affinity experiments. At equilibrium the dissociation constant and the number of binding sites per cell for IGF-I were 1.4 +/- (SE) 0.3 x 10(-9) M and 19,200 +/- 2,100, respectively. Under reduction conditions, disuccinimidyl suberate cross-linked [ 125 I]iodo-IGF-I to one receptor complex with an Mr of 125,000. Adrenal cells also contain specific insulin receptors with an apparent dissociation constant (Kd) of 10(-9) M. Under reduction conditions [ 125 I]iodo-insulin binds to one band with an approximate Mr of 125,000. IGF-I and insulin at micromolar concentrations, but not at nanomolar concentrations, slightly stimulated DNA synthesis, but markedly potentiated the mitogenic action of fibroblast growth factor. Adrenal cells cultured in a serum-free medium containing transferrin, ascorbic acid, and insulin (5 micrograms/ml) maintained fairly constant angiotensin-II (A-II) receptor concentration per cell and increased cAMP release on response to ACTH and their steroidogenic response to both ACTH and A-II. When the cells were cultured in the same medium without insulin, the number of A-II receptors significantly decreased to 65% and the increased responsiveness was blunted. Treatment of such cells for 3 days with increasing concentrations of IGF-I (1-100 ng/ml) produced a 2- to 3-fold increase in A-II receptors and enhanced the cAMP response (3- to 4-fold) to ACTH and the steroidogenic response (4- to 6-fold) to ACTH and A-II. These effects were time and dose dependent (ED50 approximately equal to 10(-9) M). Insulin at micromolar concentrations produced an effect similar to that of IGF-I, but at nanomolar concentrations the effect was far less

  4. Introduction of exogenous growth hormone receptors augments growth hormone-responsive insulin biosynthesis in rat insulinoma cells

    DEFF Research Database (Denmark)

    Billestrup, N; Møldrup, A; Serup, P

    1990-01-01

    The stimulation of insulin biosynthesis in the pancreatic insulinoma cell line RIN5-AH by growth hormone (GH) is initiated by GH binding to specific receptors. To determine whether the recently cloned rat hepatic GH receptor is able to mediate the insulinotropic effect of GH, we have transfected ...

  5. GQ-16, a Novel Peroxisome Proliferator-activated Receptor gamma (PPAR gamma) Ligand, Promotes Insulin Sensitization without Weight Gain

    NARCIS (Netherlands)

    Amato, Angelica A.; Rajagopalan, Senapathy; Lin, Jean Z.; Carvalho, Bruno M.; Figueira, Ana C. M.; Lu, Jenny; Ayers, Stephen D.; Mottin, Melina; Silveira, Rodrigo L.; Telles de Souza, Paulo; Mourao, Rosa H. V.; Saad, Mario J. A.; Togashi, Marie; Simeoni, Luiz A.; Abdalla, Dulcineia S. P.; Skaf, Munir S.; Polikparpov, Igor; Lima, Maria C. A.; Galdino, Suely L.; Brennan, Richard G.; Baxter, John D.; Pitta, Ivan R.; Webb, Paul; Phillips, Kevin J.; Neves, Francisco A. R.

    2012-01-01

    The recent discovery that peroxisome proliferator-activated receptor gamma (PPAR gamma) targeted anti-diabetic drugs function by inhibiting Cdk5-mediated phosphorylation of the receptor has provided a new viewpoint to evaluate and perhaps develop improved insulin-sensitizing agents. Herein we report

  6. Treating Diabetes Mellitus: Pharmacophore Based Designing of Potential Drugs from Gymnema sylvestre against Insulin Receptor Protein

    Directory of Open Access Journals (Sweden)

    Mohammad Uzzal Hossain

    2016-01-01

    Full Text Available Diabetes mellitus (DM is one of the most prevalent metabolic disorders which can affect the quality of life severely. Injectable insulin is currently being used to treat DM which is mainly associated with patient inconvenience. Small molecules that can act as insulin receptor (IR agonist would be better alternatives to insulin injection. Herein, ten bioactive small compounds derived from Gymnema sylvestre (G. sylvestre were chosen to determine their IR binding affinity and ADMET properties using a combined approach of molecular docking study and computational pharmacokinetic elucidation. Designing structural analogues were also performed for the compounds associated with toxicity and less IR affinity. Among the ten parent compounds, six were found to have significant pharmacokinetic properties with considerable binding affinity towards IR while four compounds were associated with toxicity and less IR affinity. Among the forty structural analogues, four compounds demonstrated considerably increased binding affinity towards IR and less toxicity compared with parent compounds. Finally, molecular interaction analysis revealed that six parent compounds and four analogues interact with the active site amino acids of IR. So this study would be a way to identify new therapeutics and alternatives to insulin for diabetic patients.

  7. Insulin-like growth factor-II (IGF II) receptor from rat brain is of lower apparent molecular weight than the IGF II receptor from rat liver

    International Nuclear Information System (INIS)

    McElduff, A.; Poronnik, P.; Baxter, R.C.

    1987-01-01

    The binding subunits of the insulin and insulin-like growth factor-I (IGF I) receptors from rat brain are of lower molecular weight than the corresponding receptor in rat liver, possibly due to variations in sialic acid content. We have compared the IGF II receptor from rat brain and rat liver. The brain receptor is of smaller apparent mol wt (about 10 K) on sodium dodecyl sulfate polyacrylamide gel electrophoresis. This size difference is independent of ligand binding as it persists in iodinated and specifically immunoprecipitated receptors. From studies of wheat germ agglutinin binding and the effect of neuraminidase on receptor mobility, we conclude that this difference is not simply due to variations in sialic acid content. Treatment with endoglycosidase F results in reduction in the molecular size of both liver and brain receptors and after this treatment the aglycoreceptors are of similar size. We conclude that in rat brain tissue the IGF II receptor like the binding subunits of the insulin and IGF I receptors is of lower molecular size than the corresponding receptors in rat liver. This difference is due to differences in N-linked glycosylation

  8. C1qTNF-related protein 1 improve insulin resistance by reducing phosphorylation of serine 1101 in insulin receptor substrate 1.

    Science.gov (United States)

    Xin, Yaping; Zhang, Dongming; Fu, Yanqin; Wang, Chongxian; Li, Qingju; Tian, Chenguang; Zhang, Suhe; Lyu, Xiaodong

    2017-08-30

    C1qTNF-related protein 1 (CTRP1) is independently associated with type 2 diabetes. However, the relationship between CTRP1 and insulin resistance is still not established. This study aimed to explore the role of CTRP1 under the situation of insulin resistance in adipose tissue. Plasma CTRP1 level was investigated in type 2 diabetic subjects (n = 35) and non-diabetic subjects (n = 35). The relationship between CTRP1 and phosphorylation of multi insulin receptor substrate 1 (IRS-1) serine (Ser) sites was further explored. Our data showed that Plasma CTRP1 was higher and negative correlation with insulin resistance in diabetic subjects (r = -0.283, p = 0.018). Glucose utilisation test revealed that the glucose utilisation rate of mature adipocytes was improved by CTRP1 in the presence of insulin. CTRP1 was not only related to IRS-1 protein, but also negatively correlated with IRS-1 Ser1101 phosphorylation (r = -0.398, p = 0.031). Furthermore, Phosphorylation levels of IRS-1 Ser1101 were significantly lower after incubation with 40 ng/mL CTRP1 in mature adipocytes than those with no intervention (p insulin resistance by reducing the phosphorylation of IRS-1 Ser1101, induced in the situation of insulin resistance as a feedback adipokine.

  9. Effect of 5'-flanking sequence deletions on expression of the human insulin gene in transgenic mice

    DEFF Research Database (Denmark)

    Fromont-Racine, M; Bucchini, D; Madsen, O

    1990-01-01

    Expression of the human insulin gene was examined in transgenic mouse lines carrying the gene with various lengths of DNA sequences 5' to the transcription start site (+1). Expression of the transgene was demonstrated by 1) the presence of human C-peptide in urine, 2) the presence of specific...... of the transgene was observed in cell types other than beta-islet cells....

  10. The A-chain of insulin contacts the insert domain of the insulin receptor. Photo-cross-linking and mutagenesis of a diabetes-related crevice.

    Science.gov (United States)

    Huang, Kun; Chan, Shu Jin; Hua, Qing-xin; Chu, Ying-Chi; Wang, Run-ying; Klaproth, Birgit; Jia, Wenhua; Whittaker, Jonathan; De Meyts, Pierre; Nakagawa, Satoe H; Steiner, Donald F; Katsoyannis, Panayotis G; Weiss, Michael A

    2007-11-30

    The contribution of the insulin A-chain to receptor binding is investigated by photo-cross-linking and nonstandard mutagenesis. Studies focus on the role of Val(A3), which projects within a crevice between the A- and B-chains. Engineered receptor alpha-subunits containing specific protease sites ("midi-receptors") are employed to map the site of photo-cross-linking by an analog containing a photoactivable A3 side chain (para-azido-Phe (Pap)). The probe cross-links to a C-terminal peptide (residues 703-719 of the receptor A isoform, KTFEDYLHNVVFVPRPS) containing side chains critical for hormone binding (underlined); the corresponding segment of the holoreceptor was shown previously to cross-link to a Pap(B25)-insulin analog. Because Pap is larger than Val and so may protrude beyond the A3-associated crevice, we investigated analogs containing A3 substitutions comparable in size to Val as follows: Thr, allo-Thr, and alpha-aminobutyric acid (Aba). Substitutions were introduced within an engineered monomer. Whereas previous studies of smaller substitutions (Gly(A3) and Ser(A3)) encountered nonlocal conformational perturbations, NMR structures of the present analogs are similar to wild-type insulin; the variant side chains are accommodated within a native-like crevice with minimal distortion. Receptor binding activities of Aba(A3) and allo-Thr(A3) analogs are reduced at least 10-fold; the activity of Thr(A3)-DKP-insulin is reduced 5-fold. The hormone-receptor interface is presumably destabilized either by a packing defect (Aba(A3)) or by altered polarity (allo-Thr(A3) and Thr(A3)). Our results provide evidence that Val(A3), a site of mutation causing diabetes mellitus, contacts the insert domain-derived tail of the alpha-subunit in a hormone-receptor complex.

  11. Insulin receptor-related receptor as an extracellular pH sensor involved in the regulation of acid-base balance.

    Science.gov (United States)

    Petrenko, Alexander G; Zozulya, Sergey A; Deyev, Igor E; Eladari, Dominique

    2013-10-01

    Recent studies of insulin receptor-related receptor (IRR) revealed its unusual property to activate upon extracellular application of mildly alkaline media, pH>7.9. The activation of IRR with hydroxyl anion has typical features of ligand-receptor interaction; it is specific, dose-dependent, involves the IRR extracellular domain and is accompanied by a major conformational change. IRR is a member of the insulin receptor minifamily and has been long viewed as an orphan receptor tyrosine kinase since no peptide or protein agonist of IRR was found. In the evolution, IRR is highly conserved since its divergence from the insulin and insulin-like growth factor receptors in amphibia. The latter two cannot be activated by alkali. Another major difference between them is that unlike ubiquitously expressed insulin and insulin-like growth factor receptors, IRR is found in specific sets of cells of only some tissues, most of them being exposed to extracorporeal liquids of extreme pH. In particular, largest concentrations of IRR are in beta-intercalated cells of the kidneys. The primary physiological function of these cells is to excrete excessive alkali as bicarbonate into urine. When IRR is removed genetically, animals loose the property to excrete bicarbonate upon experimentally induced alkalosis. In this review, we will discuss the available in vitro and in vivo data that support the hypothesis of IRR role as a physiological alkali sensor that regulates acid-base balance. This article is part of a Special Issue entitled: Emerging recognition and activation mechanisms of receptor tyrosine kinases. Copyright © 2012 Elsevier B.V. All rights reserved.

  12. Insulin binding and stimulation of hexose and amino acid transport by normal and receptor-defective human fibroblasts

    International Nuclear Information System (INIS)

    Longo, N.; Nagata, N.; Danner, D.; Priest, J.; Elsas, L.

    1986-01-01

    The authors analyzed insulin receptors in cells cultured from a sibship of related parents who had two offspring with severe insulin resistance (Leprechaunism). 124 I-Insulin (1 ng/ml) binding to skin fibroblasts from the proband, mother, and father was 9, 60 and 62% of control cells, respectively, at equilibrium, Non-linear regression analysis, utilizing a two receptors model, of curvilinear Scatchard plots indicated a reduced number of high-affinity binding sites in both parents. Influx of L-Proline (System A), L-Serine (ASC) and L-Leucine (L) was similar in control and mutant cells. Similarly, during the depletion of intracellular amino acid pools, there was a release from transinhibition for System A and a decrease of transstimulation of Systems ASC and L in both cell lines. Surprisingly, insulin augmented, normally, A system influx with an ED 50 = 70 ng/ml at 24 0 C and 7 ng/ml at 37 0 C. By contrast insulin failed to simulated 3-0-methyl-D-glucose influx into the proband's cells, while normal cells were stimulated 30% with an ED 50 of 6 ng/ml. These results indicate that defective high-affinity insulin binding is inherited as an autosomal recessive trait; that general membrane functions are intact; that insulin regulates A system amino acid and hexose transport by two different mechanisms; and, that the latter mechanism is impaired by this family's receptor mutation

  13. Developmental aspects of the rat brain insulin receptor: loss of sialic acid and fluctuation in number characterize fetal development

    International Nuclear Information System (INIS)

    Brennan, W.A. Jr.

    1988-01-01

    In this study, I have investigated the structure of the rat brain insulin receptor during fetal development. There is a progressive decrease in the apparent molecular size of the brain alpha-subunit during development: 130K on day 16 of gestation, 126K at birth, and 120K in the adult. Glycosylation was investigated as a possible reason for the observed differences in the alpha-subunit molecular size. The results show that the developmental decrease in the brain alpha-subunit apparent molecular size is due to a parallel decrease in sialic acid content. This was further confirmed by measuring the retention of autophosphorylated insulin receptors on wheat germ agglutinin (WGA)-Sepharose. An inverse correlation between developmental age and retention of 32 P-labeled insulin receptors on the lectin column was observed. Insulin binding increases 6-fold between 16 and 20 days of gestation [61 +/- 25 (+/- SE) fmol/mg protein and 364 +/- 42 fmol/mg, respectively]. Thereafter, binding in brain membranes decreases to 150 +/- 20 fmol/mg by 2 days after birth, then reaches the adult level of 63 +/- 15 fmol/mg. In addition, the degree of insulin-stimulated autophosphorylation closely parallels the developmental changes in insulin binding. Between 16 and 20 days of fetal life, insulin-stimulated phosphorylation of the beta-subunit increases 6-fold. Thereafter, the extent of phosphorylation decreases rapidly, reaching adult values identical with those in 16-day-old fetal brain. These results suggest that the embryonic brain possesses competent insulin receptors whose expression changes markedly during fetal development. This information should be important in defining the role of insulin in the developing nervous system

  14. Drosophila Insulin receptor regulates the persistence of injury-induced nociceptive sensitization

    Science.gov (United States)

    Patel, Atit A.

    2018-01-01

    ABSTRACT Diabetes-associated nociceptive hypersensitivity affects diabetic patients with hard-to-treat chronic pain. Because multiple tissues are affected by systemic alterations in insulin signaling, the functional locus of insulin signaling in diabetes-associated hypersensitivity remains obscure. Here, we used Drosophila nociception/nociceptive sensitization assays to investigate the role of Insulin receptor (Insulin-like receptor, InR) in nociceptive hypersensitivity. InR mutant larvae exhibited mostly normal baseline thermal nociception (absence of injury) and normal acute thermal hypersensitivity following UV-induced injury. However, their acute thermal hypersensitivity persists and fails to return to baseline, unlike in controls. Remarkably, injury-induced persistent hypersensitivity is also observed in larvae that exhibit either type 1 or type 2 diabetes. Cell type-specific genetic analysis indicates that InR function is required in multidendritic sensory neurons including nociceptive class IV neurons. In these same nociceptive sensory neurons, only modest changes in dendritic morphology were observed in the InRRNAi-expressing and diabetic larvae. At the cellular level, InR-deficient nociceptive sensory neurons show elevated calcium responses after injury. Sensory neuron-specific expression of InR rescues the persistent thermal hypersensitivity of InR mutants and constitutive activation of InR in sensory neurons ameliorates the hypersensitivity observed with a type 2-like diabetic state. Our results suggest that a sensory neuron-specific function of InR regulates the persistence of injury-associated hypersensitivity. It is likely that this new system will be an informative genetically tractable model of diabetes-associated hypersensitivity. PMID:29752280

  15. The insulin receptor substrate 1 associates with phosphotyrosine phosphatase SHPTP2 in liver and muscle of rats

    Directory of Open Access Journals (Sweden)

    Lima M.H.M.

    1998-01-01

    Full Text Available Insulin stimulates the tyrosine kinase activity of its receptor resulting in the phosphorylation of its cytosolic substrate, insulin receptor substrate-1 (IRS-1 which, in turn, associates with proteins containing SH2 domains. It has been shown that IRS-1 associates with the tyrosine phosphatase SHPTP2 in cell cultures. While the effect of the IRS-1/SHPTP2 association on insulin signal transduction is not completely known, this association may dephosphorylate IRS-1 and may play a critical role in the mitogenic actions of insulin. However, there is no physiological demonstration of this pathway of insulin action in animal tissues. In the present study we investigated the ability of insulin to induce association between IRS-1 and SHPTP2 in liver and muscle of intact rats, by co-immunoprecipitation with anti-IRS-1 antibody and anti-SHPTP2 antibody. In both tissues there was an increase in IRS-1 association with SHPTP2 after insulin stimulation. This association occurred when IRS-1 had the highest level of tyrosine phosphorylation and the decrease in this association was more rapid than the decrease in IRS-1 phosphorylation levels. The data provide evidence against the participation of SHPTP2 in IRS-1 dephosphorylation in rat tissues, and suggest that the insulin signal transduction pathway in rat tissues is related mainly to the mitogenic effects of the hormone.

  16. Insulin/insulin like growth factors in cancer: new roles for the aryl hydrocarbon receptor, tumor resistance mechanisms and new blocking strategies

    Directory of Open Access Journals (Sweden)

    Travis B Salisbury

    2015-02-01

    Full Text Available The insulin-like growth factor 1 receptor (IGF1R and the insulin receptor (IR are receptor tyrosine kinases (RTKs that are expressed in cancer cells. The results of different studies indicate that tumor proliferation and survival is dependent on the IGF1R and IR, and that their inhibition leads to reductions in proliferation and increases in cell death. Molecular targeting therapies that have been used in solid tumors include: anti-IGF1R antibodies, anti-IGF1/IGF2 antibodies and small molecule inhibitors that suppress IGF1R and IR kinase activity. New advances in the molecular basis of anti-IGF1R blocking antibodies reveal they are biased agonists and promote the binding of IGF1 to integrin β3 receptors in some cancer cells. Our recent reports indicate that pharmacological aryl hydrocarbon receptor (AHR ligands inhibit breast cancer cell responses to IGFs, suggesting that targeting AHR may have benefit in cancers whose proliferation and survival are dependent on insulin/IGF signaling. Novel aspects of IGF1R/IR in cancer, such as biased agonism, integrin β3 signaling, AHR and new therapeutic targeting strategies will be discussed.

  17. Novel growth hormone receptor gene mutation in a patient with Laron syndrome.

    Science.gov (United States)

    Arman, Ahmet; Yüksel, Bilgin; Coker, Ajda; Sarioz, Ozlem; Temiz, Fatih; Topaloglu, Ali Kemal

    2010-04-01

    Growth Hormone (GH) is a 22 kDa protein that has effects on growth and glucose and fat metabolisms. These effects are initiated by binding of growth hormone (GH) to growth hormone receptors (GHR) expressed in target cells. Mutations or deletions in the growth hormone receptor cause an autosomal disorder called Laron-type dwarfism (LS) characterized by high circulating levels of serum GH and low levels of insulin like growth factor-1 (IGF-1). We analyzed the GHR gene for genetic defect in seven patients identified as Laron type dwarfism. We identified two missense mutations (S40L and W104R), and four polymorphisms (S473S, L526I, G168G and exon 3 deletion). We are reporting a mutation (W104R) at exon 5 of GHR gene that is not previously reported, and it is a novel mutation.

  18. Angiotensin II receptor blocker ameliorates stress-induced adipose tissue inflammation and insulin resistance.

    Directory of Open Access Journals (Sweden)

    Motoharu Hayashi

    Full Text Available A strong causal link exists between psychological stress and insulin resistance as well with hypertension. Meanwhile, stress-related responses play critical roles in glucose metabolism in hypertensive patients. As clinical trials suggest that angiotensin-receptor blocker delays the onset of diabetes in hypertensive patients, we investigated the effects of irbesartan on stress-induced adipose tissue inflammation and insulin resistance. C57BL/6J mice were subjected to 2-week intermittent restraint stress and orally treated with vehicle, 3 and 10 mg/kg/day irbesartan. The plasma concentrations of lipid and proinflammatory cytokines [Monocyte Chemoattractant Protein-1 (MCP-1, tumor necrosis factor-α, and interleukin-6] were assessed with enzyme-linked immunosorbent assay. Monocyte/macrophage accumulation in inguinal white adipose tissue (WAT was observed with CD11b-positive cell counts and mRNA expressions of CD68 and F4/80 using immunohistochemistry and RT-PCR methods respectively. The mRNA levels of angiotensinogen, proinflammatory cytokines shown above, and adiponectin in WAT were also assessed with RT-PCR method. Glucose metabolism was assessed by glucose tolerance tests (GTTs and insulin tolerance tests, and mRNA expression of insulin receptor substrate-1 (IRS-1 and glucose transporter 4 (GLUT4 in WAT. Restraint stress increased monocyte accumulation, plasma free fatty acids, expression of angiotensinogen and proinflammatory cytokines including MCP-1, and reduced adiponectin. Irbesartan reduced stress-induced monocyte accumulation in WAT in a dose dependent manner. Irbesartan treatment also suppressed induction of adipose angiotensinogen and proinflammatory cytokines in WAT and blood, and reversed changes in adiponectin expression. Notably, irbesartan suppressed stress-induced reduction in adipose tissue weight and free fatty acid release, and improved insulin tolerance with restoration of IRS-1 and GLUT4 mRNA expressions in WAT. The results

  19. Gene Transfer and Molecular Cloning of the Human NGF Receptor

    Science.gov (United States)

    Chao, Moses V.; Bothwell, Mark A.; Ross, Alonzo H.; Koprowski, Hilary; Lanahan, Anthony A.; Buck, C. Randall; Sehgal, Amita

    1986-04-01

    Nerve growth factor (NGF) and its receptor are important in the development of cells derived from the neural crest. Mouse L cell transformants have been generated that stably express the human NGF receptor gene transfer with total human DNA. Affinity cross-linking, metabolic labeling and immunoprecipitation, and equilibrium binding with 125I-labeled NGF revealed that this NGF receptor had the same size and binding characteristics as the receptor from human melanoma cells and rat PC12 cells. The sequences encoding the NGF receptor were molecularly cloned using the human Alu repetitive sequence as a probe. A cosmid clone that contained the human NGF receptor gene allowed efficient transfection and expression of the receptor.

  20. Activation of transmembrane bile acid receptor TGR5 stimulates insulin secretion in pancreatic β cells

    International Nuclear Information System (INIS)

    Kumar, Divya P.; Rajagopal, Senthilkumar; Mahavadi, Sunila; Mirshahi, Faridoddin; Grider, John R.; Murthy, Karnam S.; Sanyal, Arun J.

    2012-01-01

    Highlights: ► G protein coupled receptor TGR5 is expressed in mouse and human islets. ► TGR5 is coupled to activation of Gs and Ca 2+ release via cAMP/Epac/PLC-ε pathway. ► Activation of TGR5 by bile salts and selective ligands causes insulin secretion. ► TGR5 could be a potential therapeutic target to treat diabetes. -- Abstract: Bile acids act as signaling molecules and stimulate the G protein coupled receptor, TGR5, in addition to nuclear farnesoid X receptor to regulate lipid, glucose and energy metabolism. Bile acid induced activation of TGR5 in the enteroendocrine cells promotes glucagon like peptide-1 (GLP-1) release, which has insulinotropic effect in the pancreatic β cells. In the present study, we have identified the expression of TGR5 in pancreatic β cell line MIN6 and also in mouse and human pancreatic islets. TGR5 selective ligands, oleanolic acid (OA) and INT-777 selectively activated Gα s and caused an increase in intracellular cAMP and Ca 2+ . OA and INT-777 also increased phosphoinositide (PI) hydrolysis and the increase was blocked by NF449 (a selective Gα s inhibitor) or (U73122) (PI hydrolysis inhibitor). OA, INT-777 and lithocholic acid increased insulin release in MIN6 and human islets and the increase was inhibited by treatment with NF449, (U73122) or BAPTA-AM (chelator of calcium), but not with myristoylated PKI (PKA inhibitor), suggesting that the release is dependent on G s /cAMP/Ca 2+ pathway. 8-pCPT-2′-O-Me-cAMP, a cAMP analog, which activates Epac, but not PKA also stimulated PI hydrolysis. In conclusion, our study demonstrates that the TGR5 expressed in the pancreatic β cells regulates insulin secretion and highlights the importance of ongoing therapeutic strategies targeting TGR5 in the control of glucose homeostasis.

  1. Insulin: its binding to specific receptors and its stimulation of DNA synthesis and 2',3'-cyclic nucleotide phosphohydrolase in embryonic mouse brain cell cultures

    International Nuclear Information System (INIS)

    Shanker, G.; Pieringer, R.A.

    1986-01-01

    Previously, the authors demonstrated that ornithine decarboxylase was stimulated by insulin in cultures of embryonic mouse brain cells. In the present work, they have investigated the presence and specificity of insulin receptors in these cultures. A time study showed that maximum binding of 125 [I] labelled insulin was around 75 min. Other studies measured the influence of concentration and age on insulin binding. A displacement study using increasing concentrations of cold insulin, glucagon or growth hormone demonstrated that the specificity of the receptors for insulin was rather high. It was also found that insulin displayed a clear dose-dependent stimulation of thymidine incorporation into the brain cells. Insulin also stimulated the glial enzyme 2':3'-cyclic nucleotide phosphohydrolase (CNP-ase). The results suggest a dual role for insulin; it regulates both cell proliferation as well as differentiation

  2. Expression and functional assessment of candidate type 2 diabetes susceptibility genes identify four new genes contributing to human insulin secretion

    Directory of Open Access Journals (Sweden)

    Fatou K. Ndiaye

    2017-06-01

    Full Text Available Objectives: Genome-wide association studies (GWAS have identified >100 loci independently contributing to type 2 diabetes (T2D risk. However, translational implications for precision medicine and for the development of novel treatments have been disappointing, due to poor knowledge of how these loci impact T2D pathophysiology. Here, we aimed to measure the expression of genes located nearby T2D associated signals and to assess their effect on insulin secretion from pancreatic beta cells. Methods: The expression of 104 candidate T2D susceptibility genes was measured in a human multi-tissue panel, through PCR-free expression assay. The effects of the knockdown of beta-cell enriched genes were next investigated on insulin secretion from the human EndoC-βH1 beta-cell line. Finally, we performed RNA-sequencing (RNA-seq so as to assess the pathways affected by the knockdown of the new genes impacting insulin secretion from EndoC-βH1, and we analyzed the expression of the new genes in mouse models with altered pancreatic beta-cell function. Results: We found that the candidate T2D susceptibility genes' expression is significantly enriched in pancreatic beta cells obtained by laser capture microdissection or sorted by flow cytometry and in EndoC-βH1 cells, but not in insulin sensitive tissues. Furthermore, the knockdown of seven T2D-susceptibility genes (CDKN2A, GCK, HNF4A, KCNK16, SLC30A8, TBC1D4, and TCF19 with already known expression and/or function in beta cells changed insulin secretion, supporting our functional approach. We showed first evidence for a role in insulin secretion of four candidate T2D-susceptibility genes (PRC1, SRR, ZFAND3, and ZFAND6 with no previous knowledge of presence and function in beta cells. RNA-seq in EndoC-βH1 cells with decreased expression of PRC1, SRR, ZFAND6, or ZFAND3 identified specific gene networks related to T2D pathophysiology. Finally, a positive correlation between the expression of Ins2 and the

  3. Insulin gene polymorphisms in type 1 diabetes, Addison's disease and the polyglandular autoimmune syndrome type II

    Directory of Open Access Journals (Sweden)

    Hahner Stefanie

    2008-07-01

    Full Text Available Abstract Background Polymorphisms within the insulin gene can influence insulin expression in the pancreas and especially in the thymus, where self-antigens are processed, shaping the T cell repertoire into selftolerance, a process that protects from β-cell autoimmunity. Methods We investigated the role of the -2221Msp(C/T and -23HphI(A/T polymorphisms within the insulin gene in patients with a monoglandular autoimmune endocrine disease [patients with isolated type 1 diabetes (T1D, n = 317, Addison's disease (AD, n = 107 or Hashimoto's thyroiditis (HT, n = 61], those with a polyglandular autoimmune syndrome type II (combination of T1D and/or AD with HT or GD, n = 62 as well as in healthy controls (HC, n = 275. Results T1D patients carried significantly more often the homozygous genotype "CC" -2221Msp(C/T and "AA" -23HphI(A/T polymorphisms than the HC (78.5% vs. 66.2%, p = 0.0027 and 75.4% vs. 52.4%, p = 3.7 × 10-8, respectively. The distribution of insulin gene polymorphisms did not show significant differences between patients with AD, HT, or APS-II and HC. Conclusion We demonstrate that the allele "C" of the -2221Msp(C/T and "A" -23HphI(A/T insulin gene polymorphisms confer susceptibility to T1D but not to isolated AD, HT or as a part of the APS-II.

  4. Effects of Steaming Time and Frequency for Manufactured Red Liriope platyphylla on the Insulin Secretion Ability and Insulin Receptor Signaling Pathway.

    Science.gov (United States)

    Choi, Sun Il; Lee, Hye Ryun; Goo, Jun Seo; Kim, Ji Eun; Nam, So Hee; Hwang, In Sik; Lee, Young Ju; Prak, So Hae; Lee, Hee Seob; Lee, Jong Sup; Jang, In Surk; Son, Hong Ju; Hwang, Dae Youn

    2011-06-01

    In oriental medicine, Liriope platyphylla (LP) has long been regarded as a curative herb useful for the treatment of diabetes, asthma, and neurodegenerative disorders. The principal objective of this study was to assess the effects of steaming time and frequency for manufactured Red LP (RLP) on insulin secretion ability and insulin receptor signaling pathway. To achieve our goal, several types of LPs manufactured under different conditions were applied to INS cells and streptozotocin (STZ)-induced diabetic ICR mice, after which alterations in insulin concentrations were detected in the culture supernatants and sera. The optimal concentration for the investigation of insulin secretion ability was found to be 50 ug/mL of LP. At this concentration, maximum insulin secretion was observed in the INS cells treated with LP extract steamed for 3 h (3-SLP) with two repeated steps (3 h steaming and 24 h air-dried) carried out 9 times (9-SALP); no significant changes in viability were detected in any of the treated cells. Additionally, the expression and phosphorylation levels of most components in the insulin receptor signaling pathway were increased significantly in the majority of cells treated with steaming-processed LP as compared to the cells treated with LP prepared without steaming. With regard to glucose transporter (GLUT) expression, alterations of steaming time induced similar responses on the expression levels of GLUT-2 and GLUT-3. However, differences in steaming frequency were also shown to induce dose-dependent responses in the expression level of GLUT-2 only; no significant differences in GLUT-3 expression were detected under these conditions. Furthermore, these responses observed in vitro were similarly detected in STZ-induced diabetic mice. 24-SLP and 9-SALP treatment applied for 14 days induced the down-regulation of glucose concentration and upregulation of insulin concentration. Therefore, these results indicated that the steaming processed LP may

  5. Hepatitis C virus nonstructural protein 5A favors upregulation of gluconeogenic and lipogenic gene expression leading towards insulin resistance: a metabolic syndrome.

    Science.gov (United States)

    Parvaiz, Fahed; Manzoor, Sobia; Iqbal, Jawed; McRae, Steven; Javed, Farrakh; Ahmed, Qazi Laeeque; Waris, Gulam

    2014-05-01

    Chronic hepatitis C is a lethal blood-borne infection often associated with a number of pathologies such as insulin resistance and other metabolic abnormalities. Insulin is a key hormone that regulates the expression of metabolic pathways and favors homeostasis. In this study, we demonstrated the molecular mechanism of hepatitis C virus (HCV) nonstructural protein 5A (NS5A)-induced metabolic dysregulation. We showed that transient expression of HCV NS5A in human hepatoma cells increased lipid droplet formation through enhanced lipogenesis. We also showed increased transcriptional expression of peroxisome proliferator-activated receptor gamma coactivator (PGC)-1α and diacylglycerol acyltransferase-1 (DGAT-1) in NS5A-expressing cells. On the other hand, there was significantly reduced transcriptional expression of microsomal triglyceride transfer protein (MTP) and peroxisome proliferator-activated receptor γ (PPARγ) in cells expressing HCV NS5A. Furthermore, increased gluconeogenic gene expression was observed in HCV-NS5A-expressing cells. In addition, it was also shown that HCV-NS5A-expressing hepatoma cells show serine phosphorylation of IRS-1, thereby hampering metabolic activity and contributing to insulin resistance. Therefore, this study reveals that HCV NS5A is involved in enhanced gluconeogenic and lipogenic gene expression, which triggers metabolic abnormality and impairs insulin signaling pathway.

  6. Control of transcriptional repression of the vitellogenin receptor gene in largemouth bass (Micropterus salmoides) by select estrogen receptors isotypes.

    Science.gov (United States)

    Dominguez, Gustavo A; Bisesi, Joseph H; Kroll, Kevin J; Denslow, Nancy D; Sabo-Attwood, Tara

    2014-10-01

    The vitellogenin receptor (Vtgr) plays an important role in fish reproduction. This receptor functions to incorporate vitellogenin (Vtg), a macromolecule synthesized and released from the liver in the bloodstream, into oocytes where it is processed into yolk. Although studies have focused on the functional role of Vtgr in fish, the mechanistic control of this gene is still unexplored. Here we report the identification and analysis of the first piscine 5' regulatory region of the vtgr gene which was cloned from largemouth bass (Micropterus salmoides). Using this putative promoter sequence, we investigated a role for hormones, including insulin and 17β-estradiol (E2), in transcriptional regulation through cell-based reporter assays. No effect of insulin was observed, however, E2 was able to repress transcriptional activity of the vtgr promoter through select estrogen receptor subtypes, Esr1 and Esr2a but not Esr2b. Electrophoretic mobility shift assay demonstrated that Esr1 likely interacts with the vtgr promoter region through half ERE and/or SP1 sites, in part. Finally we also show that ethinylestradiol (EE2), but not bisphenol-A (BPA), represses promoter activity similarly to E2. These results reveal for the first time that the Esr1 isoform may play an inhibitory role in the expression of LMB vtgr mRNA under the influence of E2, and potent estrogens such as EE2. In addition, this new evidence suggests that vtgr may be a target of select endocrine disrupting compounds through environmental exposures. © The Author 2014. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  7. Synthesis and Evaluation of a Library of Trifunctional Scaffold-Derived Compounds as Modulators of the Insulin Receptor

    Czech Academy of Sciences Publication Activity Database

    Fabre, Benjamin; Pícha, Jan; Vaněk, Václav; Selicharová, Irena; Chrudinová, Martina; Collinsová, Michaela; Žáková, Lenka; Buděšínský, Miloš; Jiráček, Jiří

    2016-01-01

    Roč. 18, č. 12 (2016), s. 710-722 ISSN 2156-8952 R&D Projects: GA ČR GA14-17305S Institutional support: RVO:61388963 Keywords : insulin mimetics * insulin receptor * library * protein-protein interactions * scaffold * trifunctional Subject RIV: CE - Biochemistry Impact factor: 3.168, year: 2016 http://pubs.acs.org/doi/full/10.1021/acscombsci.6b00132

  8. Insulin use, hormone receptor status and hematopoietic cytokines׳ circulation in women with diabetes mellitus and breast cancer

    Directory of Open Access Journals (Sweden)

    Zachary A.P. Wintrob

    2017-04-01

    The data presented here is among the first to show a relationship between pre-existing use of injectable insulin in women diagnosed with breast cancer and type 2 diabetes mellitus, hematopoietic cytokine profiles at time of breast cancer diagnosis, and subsequent cancer outcomes. A Pearson correlation analysis evaluating the relationship between G-CSF, GM-CSF, and IL-7 stratified by insulin use, controls, as well as by estrogen and progesterone receptor status is also provided.

  9. Inhibition of central insulin-receptor signaling by S961 causes hyperglycemia and glucose intolerance in rats

    OpenAIRE

    Ajit Vikram; Gopabandhu Jena

    2011-01-01

    Genetic ablation studies confirmed the role of central insulin-receptor signaling (CIRS) in fuel metabolism. However, the need to examine the role of CIRS in glucose homeostasis under normal physiological condition is indispensable, as insulin affects the neuronal growth, differentiation and synaptic plasticity. Intracerebral administration of S961 induced hyperglycemia and glucose intolerance in normal rats, and provided direct evidence for the involvement of CIRS in the regulation of glucos...

  10. Immature transformed rat islet beta-cells differentially express C-peptides derived from the genes coding for insulin I and II as well as a transfected human insulin gene

    DEFF Research Database (Denmark)

    Blume, N; Petersen, J S; Andersen, L C

    1992-01-01

    is induced in the transformed heterogeneous rat islet cell clone, NHI-6F, by transient in vivo passage. During this process a transfected human insulin gene is coactivated with the endogenous nonallelic rat insulin I and II genes. Newly established cultures from NHI-6F insulinomas having a high frequency...

  11. The role of G-protein-coupled receptors in mediating the effect of fatty acids on inflammation and insulin sensitivity.

    Science.gov (United States)

    Oh, Da Young; Lagakos, William S

    2011-07-01

    Chronic activation of inflammatory pathways mediates the pathogenesis of insulin resistance, and the macrophage/adipocyte nexus provides a key mechanism underlying decreased insulin sensitivity. Free fatty acids are important in the pathogenesis of insulin resistance, although their precise mechanisms of action have yet to be fully elucidated. Recently, a family of G-protein-coupled receptors has been identified that exhibits high affinity for fatty acids. This review summarizes recent findings on six of these receptors, their ligands, and their potential physiological functions in vivo. Upon activation, the free fatty acid receptors affect inflammation, glucose metabolism, and insulin sensitivity. Genetic deletion of GPR40 and GPR41, receptors for long-chain and short-chain fatty acids, respectively, results in resistance to diet-induced obesity. Deletion of GPR43 and GPR84 exacerbates inflammation, and deletion of the long-chain fatty acid receptors GPR119 and GPR120 reduces or is predicted to reduce glucose tolerance. These studies provide a new understanding of the general biology of gastric motility and also shed valuable insight into some potentially beneficial therapeutic targets. Furthermore, highly selective agonists or antagonists for the free fatty acid receptors have been developed and look promising for treating various metabolic diseases.

  12. Insulin, Central Dopamine D2 Receptors, and Monetary Reward Discounting in Obesity.

    Directory of Open Access Journals (Sweden)

    Sarah A Eisenstein

    Full Text Available Animal research finds that insulin regulates dopamine signaling and reward behavior, but similar research in humans is lacking. We investigated whether individual differences in body mass index, percent body fat, pancreatic β-cell function, and dopamine D2 receptor binding were related to reward discounting in obese and non-obese adult men and women. Obese (n = 27; body mass index>30 and non-obese (n = 20; body mass index<30 adults were assessed for percent body fat with dual-energy X-ray absorptiometry and for β-cell function using disposition index. Choice of larger, but delayed or less certain, monetary rewards relative to immediate, certain smaller monetary rewards was measured using delayed and probabilistic reward discounting tasks. Positron emission tomography using a non-displaceable D2-specific radioligand, [11C](N-methylbenperidol quantified striatal D2 receptor binding. Groups differed in body mass index, percent body fat, and disposition index, but not in striatal D2 receptor specific binding or reward discounting. Higher percent body fat in non-obese women related to preference for a smaller, certain reward over a larger, less likely one (greater probabilistic discounting. Lower β-cell function in the total sample and lower insulin sensitivity in obese related to stronger preference for an immediate and smaller monetary reward over delayed receipt of a larger one (greater delay discounting. In obese adults, higher striatal D2 receptor binding related to greater delay discounting. Interestingly, striatal D2 receptor binding was not significantly related to body mass index, percent body fat, or β-cell function in either group. Our findings indicate that individual differences in percent body fat, β-cell function, and striatal D2 receptor binding may each contribute to altered reward discounting behavior in non-obese and obese individuals. These results raise interesting questions about whether and how striatal D2 receptor binding

  13. Metabolism and insulin signaling in common metabolic disorders and inherited insulin resistance

    DEFF Research Database (Denmark)

    Højlund, Kurt

    2014-01-01

    . These metabolic disorders are all characterized by reduced plasma adiponectin and insulin resistance in peripheral tissues. Quantitatively skeletal muscle is the major site of insulin resistance. Both low plasma adiponectin and insulin resistance contribute to an increased risk of type 2 diabetes...... described a novel syndrome characterized by postprandial hyperinsulinemic hypoglycemia and insulin resistance. This syndrome is caused by a mutation in the tyrosine kinase domain of the insulin receptor gene (INSR). We have studied individuals with this mutation as a model of inherited insulin resistance....... Type 2 diabetes, obesity and PCOS are characterized by pronounced defects in the insulin-stimulated glucose uptake, in particular glycogen synthesis and to a lesser extent glucose oxidation, and the ability of insulin to suppress lipid oxidation. In inherited insulin resistance, however, only insulin...

  14. Novel nuclear localization and potential function of insulin-like growth factor-1 receptor/insulin receptor hybrid in corneal epithelial cells.

    Directory of Open Access Journals (Sweden)

    Yu-Chieh Wu

    Full Text Available BACKGROUND: Type I insulin-like growth factor receptor (IGF-1R and insulin receptor (INSR are highly homologous molecules, which can heterodimerize to form an IGF-1R/INSR hybrid (Hybrid-R. The presence and biological significance of the Hybrid-R in human corneal epithelium has not yet been established. In addition, while nuclear localization of IGF-1R was recently reported in cancer cells and human corneal epithelial cells, the function and profile of nuclear IGF-1R is unknown. In this study, we characterized the nuclear localization and function of the Hybrid-R and the role of IGF-1/IGF-1R and Hybrid-R signaling in the human corneal epithelium. METHODOLOGY/PRINCIPLE FINDINGS: IGF-1-mediated signaling and cell growth were examined in a human telomerized corneal epithelial (hTCEpi cell line using co-immunoprecipitation, immunoblotting and cell proliferation assays. The presence of Hybrid-R in hTCEpi and primary cultured human corneal epithelial cells was confirmed by immunofluorescence and reciprocal immunoprecipitation of whole cell lysates. We found that IGF-1 stimulated Akt and promoted cell growth through IGF-1R activation, which was independent of the Hybrid-R. The presence of Hybrid-R, but not IGF-1R/IGF-1R, was detected in nuclear extracts. Knockdown of INSR by small interfering RNA resulted in depletion of the INSR/INSR and preferential formation of Hybrid-R. Chromatin-immunoprecipitation sequencing assay with anti-IGF-1R or anti-INSR was subsequently performed to identify potential genomic targets responsible for critical homeostatic regulatory pathways. CONCLUSION/SIGNIFICANCE: In contrast to previous reports on nuclear localized IGF-1R, this is the first report identifying the nuclear localization of Hybrid-R in an epithelial cell line. The identification of a nuclear Hybrid-R and novel genomic targets suggests that IGF-1R traffics to the nucleus as an IGF-1R/INSR heterotetrameric complex to regulate corneal epithelial homeostatic

  15. Autoradiographic visualization of insulin-like growth factor-II receptors in rat brain

    International Nuclear Information System (INIS)

    Mendelsohn, L.G.; Kerchner, G.A.; Clemens, J.A.; Smith, M.C.

    1986-01-01

    The documented presence of IGF-II in brain and CSF prompted us to investigate the distribution of receptors for IGF-II in rat brain slices. Human 125 -I-IGF-II (10 pM) was incubated for 16 hrs at 4 0 C with slide-mounted rat brain slices in the absence and presence of unlabeled human IGF-II (67 nM) or human insulin (86 nM). Slides were washed, dried, and exposed to X-ray film for 4-7 days. The results showed dense labeling in the granular layers of the olfactory bulbs, deep layers of the cerebral cortex, pineal gland, anterior pituitary, hippocampus (pyramidal cells CA 1 -CA 2 and dentate gyrus), and the granule cell layers of the cerebellum. Unlabeled IGF-II eliminated most of the binding of these brain regions while insulin produced only a minimal reduction in the amount of 125 I-IGF-II bound. These results indicate that a specific neural receptor for IGS-II is uniquely distributed in rat brain tissue and supports the notion that this peptide might play an important role in normal neuronal functioning

  16. Insulin-like growth factor receptor inhibitors: baby or the bathwater?

    Science.gov (United States)

    Yee, Douglas

    2012-07-03

    The success of targeted therapies for cancer is undisputed; strong preclinical evidence has resulted in the approval of several new agents for cancer treatment. The type I insulin-like growth factor receptor (IGF1R) appeared to be one of these promising new targets. Substantial population and preclinical data have all pointed toward this pathway as an important regulator of tumor cell biology. Although early results from clinical trials that targeted the IGF1R showed some evidence of response, larger randomized phase III trials have not shown clear clinical benefit of targeting this pathway in combination with conventional strategies. These disappointing results have resulted in the discontinuation of several anti-IGF1R programs. However, the conduct of these trials has brought to the forefront several important factors that need to be considered in the conduct of future clinical trials. The need to develop biomarkers, a clearer understanding of insulin receptor function, and defining rational combination regimens all require further consideration. In this commentary, the current state of IGF1R inhibitors in cancer therapy is reviewed.

  17. Functional insulin receptors are overexpressed in thyroid tumors: is this an early event in thyroid tumorigenesis?

    Science.gov (United States)

    Frittitta, L; Sciacca, L; Catalfamo, R; Ippolito, A; Gangemi, P; Pezzino, V; Filetti, S; Vigneri, R

    1999-01-15

    Insulin receptor (IR), a member of the receptor tyrosine kinase family, is expressed in normal thyroid cells and affects thyroid cell proliferation and differentiation. The authors measured IR content in benign and malignant thyroid tumors by three independent methods: a specific radioimmunoassay, 125I-insulin binding studies, and immunohistochemistry. The results obtained were compared with the IR content in paired, adjacent, normal thyroid tissue. To assess IR function in thyroid carcinoma cells, glucose uptake responsiveness to insulin was also studied in a human transformed thyroid cell line (B-CPAP) and in follicular carcinoma cells in primary culture. In 9 toxic adenomas, the average IR content was similar to that observed in the 9 paired normal thyroid tissue specimens from the same patients (2.2+/-0.3 vs. 2.1+/-0.3). In 13 benign nonfunctioning, or "cold," adenomas, the average IR content was significantly higher (P thyroid tissue (4.0+/-0.4 vs. 1.6+/-0.2 and 5.6+/-1.0 vs. 1.8+/-0.2, respectively). The finding of a higher IR content in benign "cold" adenomas and in thyroid carcinomas was confirmed by both binding and immunostaining studies. The current studies indicate that 1) IR content is elevated in most follicular and papillary differentiated thyroid carcinomas, and 2) IR content is also elevated in most benign follicular adenomas ("cold" nodules) but not in highly differentiated, hyperfunctioning follicular adenomas ("hot" nodules), which very rarely become malignant. This observation suggests that increased IR expression is not restricted to the thyroid malignant phenotype but is already present in the premalignant "cold" adenomas. It may contribute, therefore, to thyroid tumorigenesis and/or represent an early event that gives a selective growth advantage to transformed thyroid cells.

  18. Insulin, IGF-1, and GH Receptors Are Altered in an Adipose Tissue Depot-Specific Manner in Male Mice With Modified GH Action.

    Science.gov (United States)

    Hjortebjerg, Rikke; Berryman, Darlene E; Comisford, Ross; Frank, Stuart J; List, Edward O; Bjerre, Mette; Frystyk, Jan; Kopchick, John J

    2017-05-01

    Growth hormone (GH) is a determinant of glucose homeostasis and adipose tissue (AT) function. Using 7-month-old transgenic mice expressing the bovine growth hormone (bGH) gene and growth hormone receptor knockout (GHR-/-) mice, we examined whether changes in GH action affect glucose, insulin, and pyruvate tolerance and AT expression of proteins involved in the interrelated signaling pathways of GH, insulinlike growth factor 1 (IGF-1), and insulin. Furthermore, we searched for AT depot-specific differences in control mice. Glycated hemoglobin levels were reduced in bGH and GHR-/- mice, and bGH mice displayed impaired gluconeogenesis as judged by pyruvate tolerance testing. Serum IGF-1 was elevated by 90% in bGH mice, whereas IGF-1 and insulin were reduced by 97% and 61% in GHR-/- mice, respectively. Igf1 RNA was increased in subcutaneous, epididymal, retroperitoneal, and brown adipose tissue (BAT) depots in bGH mice (mean increase ± standard error of the mean in all five depots, 153% ± 27%) and decreased in all depots in GHR-/- mice (mean decrease, 62% ± 4%). IGF-1 receptor expression was decreased in all AT depots of bGH mice (mean decrease, 49% ± 6%) and increased in all AT depots of GHR-/- mice (mean increase, 94% ± 8%). Insulin receptor expression was reduced in retroperitoneal, mesenteric, and BAT depots in bGH mice (mean decrease in all depots, 56% ± 4%) and augmented in subcutaneous, retroperitoneal, mesenteric, and BAT depots in GHR-/- mice (mean increase: 51% ± 1%). Collectively, our findings indicate a role for GH in influencing hormone signaling in AT in a depot-dependent manner. Copyright © 2017 Endocrine Society.

  19. Human blood-brain barrier insulin-like growth factor receptor

    International Nuclear Information System (INIS)

    Duffy, K.R.; Pardridge, W.M.; Rosenfeld, R.G.

    1988-01-01

    Insulin-like growth factor (IGF)-1 and IGF-2, may be important regulatory molecules in the CNS. Possible origins of IGFs in brain include either de novo synthesis or transport of circulating IGFs from blood into brain via receptor mediated transcytosis mechanisms at the brain capillary endothelial wall, ie, the blood-brain barrier (BBB). In the present studies, isolated human brain capillaries are used as an in vitro model system of the human BBB and the characteristics of IGF-1 or IGF-2 binding to this preparation were assessed. The total binding of IGF-2 at 37 degrees C exceeded 130% per mg protein and was threefold greater than the total binding for IGF-1. However, at 37 degrees C nonsaturable binding equaled total binding, suggesting that endocytosis is rate limiting at physiologic temperatures. Binding studies performed at 4 degrees C slowed endocytosis to a greater extent than membrane binding, and specific binding of either IGF-1 or IGF-2 was detectable. Scatchard plots for either peptide were linear and the molar dissociation constant of IGF-1 and IGF-2 binding was 2.1 +/- 0.4 and 1.1 +/- 0.1 nmol/L, respectively. Superphysiologic concentrations of porcine insulin inhibited the binding of both IGF-1 (ED50 = 2 micrograms/mL) and IGF-2 (ED50 = 0.5 microgram/mL). Affinity cross linking of 125 I-IGF-1, 125 I-IGF-2, and 125 I-insulin to isolated human brain capillaries was performed using disuccinimidylsuberate (DSS). These studies revealed a 141 kd binding site for both IGF-1 and IGF-2, and a 133 kd binding site for insulin

  20. The complement anaphylatoxin C5a receptor contributes to obese adipose tissue inflammation and insulin resistance.

    Science.gov (United States)

    Phieler, Julia; Chung, Kyoung-Jin; Chatzigeorgiou, Antonios; Klotzsche-von Ameln, Anne; Garcia-Martin, Ruben; Sprott, David; Moisidou, Maria; Tzanavari, Theodora; Ludwig, Barbara; Baraban, Elena; Ehrhart-Bornstein, Monika; Bornstein, Stefan R; Mziaut, Hassan; Solimena, Michele; Karalis, Katia P; Economopoulou, Matina; Lambris, John D; Chavakis, Triantafyllos

    2013-10-15

    Obese adipose tissue (AT) inflammation contributes critically to development of insulin resistance. The complement anaphylatoxin C5a receptor (C5aR) has been implicated in inflammatory processes and as regulator of macrophage activation and polarization. However, the role of C5aR in obesity and AT inflammation has not been addressed. We engaged the model of diet-induced obesity and found that expression of C5aR was significantly upregulated in the obese AT, compared with lean AT. In addition, C5a was present in obese AT in the proximity of macrophage-rich crownlike structures. C5aR-sufficient and -deficient mice were fed a high-fat diet (HFD) or a normal diet (ND). C5aR deficiency was associated with increased AT weight upon ND feeding in males, but not in females, and with increased adipocyte size upon ND and HFD conditions in males. However, obese C5aR(-/-) mice displayed improved systemic and AT insulin sensitivity. Improved AT insulin sensitivity in C5aR(-/-) mice was associated with reduced accumulation of total and proinflammatory M1 macrophages in the obese AT, increased expression of IL-10, and decreased AT fibrosis. In contrast, no difference in β cell mass was observed owing to C5aR deficiency under an HFD. These results suggest that C5aR contributes to macrophage accumulation and M1 polarization in the obese AT and thereby to AT dysfunction and development of AT insulin resistance.

  1. 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...

  2. Systemic administration of kainic acid induces selective time dependent decrease in [125I]insulin-like growth factor I, [125I]insulin-like growth factor II and [125I]insulin receptor binding sites in adult rat hippocampal formation

    International Nuclear Information System (INIS)

    Quirion, R.; Chabot, J.-G.; Dore, S.; Seto, D.; Kar, S.

    1997-01-01

    Administration of kainic acid evokes acute seizure in hippocampal pathways that results in a complex sequence of functional and structural alterations resembling human temporal lobe epilepsy. The structural alterations induced by kainic acid include selective loss of neurones in CA1-CA3 subfields and the hilar region of the dentate gyrus followed by sprouting and permanent reorganization of the synaptic connections of the mossy fibre pathways. Although the neuronal degeneration and process of reactive synaptogenesis have been extensively studied, at present little is known about means to prevent pathological conditions leading to kainate-induced cell death. In the present study, to address the role of insulin-like growth factors I and II, and insulin in neuronal survival as well as synaptic reorganization following kainate-induced seizure, the time course alterations of the corresponding receptors were evaluated. Additionally, using histological preparations, the temporal profile of neuronal degeneration and hypertrophy of resident astroglial cells were also studied. [ 125 I]Insulin-like growth factor I binding was found to be decreased transiently in almost all regions of the hippocampal formation at 12 h following treatment with kainic acid. The dentate hilar region however, exhibited protracted decreases in [ 125 I]insulin-like growth factor I receptor sites throughout (i.e. 30 days) the study. [ 125 I]Insulin-like growth factor II receptor binding sites in the hippocampal formation were found to be differentially altered following systemic administration of kainic acid. A significant decrease in [ 125 I]insulin-like growth factor II receptor sites was observed in CA1 subfield and the pyramidal cell layer of the Ammon's horn at all time points studied whereas the hilar region and the stratum radiatum did not exhibit alteration at any time. A kainate-induced decrease in [ 125 I]insulin receptor binding was noted at all time points in the molecular layer of the

  3. Tissue-specific expression of transfected human insulin genes in pluripotent clonal rat insulinoma lines induced during passage in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Madsen, O.D.; Andersen, L.C.; Michelsen, B.; Owerbach, D.; Larsson, L.I.; Lernmark, A.; Steiner, D.F. (Hagedorn Research Laboratory, Gentofte (Denmark))

    1988-09-01

    The pluripotent rat islet tumor cell line MSL-G2 expresses primarily glucagon or cholecystokinin and not insulin in vitro but changes phenotype completely after prolonged in vivo cultivation to yield small-sized hypoglycemic tumors composed almost entirely of insulin-producing beta cells. When a genomic DNA fragment containing the coding and upstream regulatory regions of the human insulin gene was stably transfected into MSL-G2 cells no measurable amounts of insulin or insulin mRNA were detected in vitro. However, successive transplantation of two transfected clones resulted in hypoglycemic tumors that efficiently coexpressed human and rat insulin as determined by human C-peptide-specific immunoreagents. These results demonstrate that cis-acting tissue-specific insulin gene enhancer elements are conserved between rat and human insulin genes. The authors propose that the in vivo differentiation of MSL-G2 cells and transfected subclones into insulin-producing cells reflects processes of natural beta-cell ontogeny leading to insulin gene expression.

  4. Tissue-specific expression of transfected human insulin genes in pluripotent clonal rat insulinoma lines induced during passage in vivo

    International Nuclear Information System (INIS)

    Madsen, O.D.; Andersen, L.C.; Michelsen, B.; Owerbach, D.; Larsson, L.I.; Lernmark, A.; Steiner, D.F.

    1988-01-01

    The pluripotent rat islet tumor cell line MSL-G2 expresses primarily glucagon or cholecystokinin and not insulin in vitro but changes phenotype completely after prolonged in vivo cultivation to yield small-sized hypoglycemic tumors composed almost entirely of insulin-producing beta cells. When a genomic DNA fragment containing the coding and upstream regulatory regions of the human insulin gene was stably transfected into MSL-G2 cells no measurable amounts of insulin or insulin mRNA were detected in vitro. However, successive transplantation of two transfected clones resulted in hypoglycemic tumors that efficiently coexpressed human and rat insulin as determined by human C-peptide-specific immunoreagents. These results demonstrate that cis-acting tissue-specific insulin gene enhancer elements are conserved between rat and human insulin genes. The authors propose that the in vivo differentiation of MSL-G2 cells and transfected subclones into insulin-producing cells reflects processes of natural beta-cell ontogeny leading to insulin gene expression

  5. Comparative evaluation of optical methods and conventional isotope techniques for the detection of insulin receptors in heterogenous cell systems

    International Nuclear Information System (INIS)

    Thun, C.

    1984-01-01

    The findings of studies using radioactively labelled (I-125) insulin to characterise its binding to various heterogenous cell systems had led to a classification of the relevant receptors with those of high affinity and low capacity or vice versa. This, in turn, raised questions as to the binding properties of each individual cell or cell material of a heterogenous nature. Apparently homogenous (lymphocytes) and heterogenous (blood and islet cells) cell populations were investigated on the basis of various techniques for the separate evaluation of individual cells, which were cytofluorometry using FITC insulin and the analysis of gold insulin under the electron microscope. For the association kinetics and equilibration analysis or affinity and receptor quantity a radioactive tracer and light microscope were used. Insulin was shown to bind to erythrocytes, reticulocytes, monocytes and lymphocytes and this result finds confirmation in the relevant literature. Furthermore, binding parameters could be determined for isolated islet cells. Cytofluorometry pointed to the fact that the insulin receptors of an apparently homogenous cell system differed in affinity and number and permitted the use of a multiple parameter procedure. Thus, it holds out promise as a method to be routinely used in the clinical diagnosis of binding parameters, without requiring previous separation procedures that are complicated or involve a loss of material. Transmission electron microscopy permitted conclusions to be drawn as to the type of cell to which insulin is attached. Owing to the use of gold insulin it was possible to throw some light on the factors determining the fate of membrane-bound insulin during its uptake into the cell. (TRV) [de

  6. Polymorphisms and haplotypes in the bovine neuropeptide Y, growth hormone receptor, ghrelin, insulin-like growth factor 2, and uncoupling proteins 2 and 3 genes and their associations with measures of growth, performance, feed efficiency, and carcass merit in beef cattle.

    Science.gov (United States)

    Sherman, E L; Nkrumah, J D; Murdoch, B M; Li, C; Wang, Z; Fu, A; Moore, S S

    2008-01-01

    Genes that regulate metabolism and energy partitioning have the potential to influence economically important traits in farm animals, as do polymorphisms within these genes. In the current study, SNP in the bovine neuropeptide Y (NPY), growth hormone receptor (GHR), ghrelin (GHRL), uncoupling proteins 2 and 3 (UCP2 and UCP3), IGF2, corticotrophin-releasing hormone (CRH), cocaine and amphetamine regulated transcript (CART), melanocortin-4 receptor (MC4R), proopiomelanocortin (POMC), and GH genes were evaluated for associations with growth, feed efficiency, and carcass merit in beef steers. In total, 24 SNP were evaluated for associations with these traits and haplotypes were constructed within each gene when 2 or more SNP showed significant associations. An A/G SNP located in intron 4 of the GHR gene had the largest effects on BW of the animals (dominance effect P GHRL gene tended to show effects on residual feed intake, FCR, and partial efficiency of growth (P < 0.10). The IGF2 SNP most strongly affected LM area (P < 0.01), back fat, ADG, and FCR (P < 0.05). The SNP in the CART, MC4R, POMC, GH, and CRH genes did not show associations at P < 0.05 with any of the traits. Although most of the SNP that showed associations do not cause amino acid changes, these SNP could be linked to other yet to be detected causative mutations or nearby QTL. It will be very important to verify these results in other cattle populations.

  7. Gastro-Resistant Insulin Receptor-Binding Peptide from Momordica charantia Improved the Glucose Tolerance in Streptozotocin-Induced Diabetic Mice via Insulin Receptor Signaling Pathway.

    Science.gov (United States)

    Lo, Hsin-Yi; Li, Chia-Cheng; Chen, Feng-Yuan; Chen, Jaw-Chyun; Hsiang, Chien-Yun; Ho, Tin-Yun

    2017-10-25

    Momordica charantia is a commonly used food and has been used for the management of diabetes. Our previous study has identified an insulin receptor (IR)-binding protein (mcIRBP) from Momordica charantia. Here we identified the gastro-resistant hypoglycemic bioactive peptides from protease-digested mcIRBP. By in vitro digestion and IR kinase activity assay, we found that a 9-amino-acid-residue peptide, mcIRBP-9, was a gastro-resistant peptide that enhanced IR kinase activities. mcIRBP-9 activated IR signaling transduction pathway, which resulted in the phosphorylation of IR, the translocation of glucose transporter 4, and the uptake of glucose in cells. Intraperitoneal and oral administration of mcIRBP-9 stimulated the glucose clearance by 30.91 ± 0.39% and 32.09 ± 0.38%, respectively, in streptozotocin-induced diabetic mice. Moreover, a pilot study showed that daily ingestion of mcIRBP-9 for 30 days decreased the fasting blood glucose levels and glycated hemoglobin (HbA1c) levels by 23.62 ± 6.14% and 24.06 ± 1.53%, respectively. In conclusion, mcIRBP-9 is a unique gastro-resistant bioactive peptide generated after the digestion of mcIRBP. Furthermore, oral administration of mcIRBP-9 improves both the glucose tolerance and the HbA1c levels in diabetic mice via targeting IR signaling transduction pathway.

  8. Impact of estrogen receptor α gene and oxytocin receptor gene polymorphisms on female sexuality

    Directory of Open Access Journals (Sweden)

    Anastasia K Armeni

    2017-02-01

    Full Text Available Over the past decades, research attention has increasingly been paid to the neurobiological component of sexual behavior. The aim of the present study was to investigate the correlation of estrogen receptor α (ERA gene polymorphism (rs2234693-PvuII (T→C substitution and oxytocin receptor gene polymorphism (rs53576 (G→A substitution with sexuality parameters of young, healthy women. One hundred thirty-three Greek heterosexual women, students in higher education institutions, 20–25 years of age, sexually active, with normal menstrual cycles (28–35 days, were recruited in the study. Exclusion criteria were chronic and/or major psychiatric diseases, use of oral contraceptive pills (OCs, polycystic ovary syndrome (PCOS, thyroid diseases as well as drugs that are implicated in hypothalamus–pituitary–gonadal axis. T allele (wildtype of rs2234693 (PvuII polymorphism of ERA gene was correlated with increased levels of arousal and lubrication, whereas A allele (polymorphic of rs53576 (OXTR polymorphism was correlated with increased arousal levels. The simultaneous presence of both T allele of rs2234693 (PvuII and A allele of rs53576 (OXTR polymorphisms (T + A group was correlated with increased arousal, orgasm levels as well as female sexual function index full score. To our knowledge, this is the first study to investigate the interaction between ERA and OXTR with regard to sexual function in women. Female sexuality is a complex behavioral trait that encompasses both biological and psychological components. It seems that variability in female sexual response stems from genetic variability that characterizes endocrine, neurotransmitter and central nervous system influences.

  9. Receptor-mediated endocytosis and intracellular trafficking of insulin and low-density lipoprotein by retinal vascular endothelial cells.

    Science.gov (United States)

    Stitt, A W; Anderson, H R; Gardiner, T A; Bailie, J R; Archer, D B

    1994-08-01

    The authors investigated the receptor-mediated endocytosis (RME) and intracellular trafficking of insulin and low-density lipoprotein (LDL) in cultured retinal vascular endothelial cells (RVECs). Low-density lipoprotein and insulin were conjugated to 10 nm colloidal gold, and these ligands were added to cultured bovine RVECs for 20 minutes at 4 degrees C. The cultures were then warmed to 37 degrees C and fixed after incubation times between 30 seconds and 1 hour. Control cells were incubated with unconjugated gold colloid at times and concentrations similar to those of the ligands. Additional control cells were exposed to several concentrations of anti-insulin receptor antibody or a saturating solution of unconjugated insulin before incubation with gold insulin. Using transmission electron microscopy, insulin gold and LDL gold were both observed at various stages of RME. Insulin-gold particles were first seen to bind to the apical plasma membrane (PM) before clustering in clathrin-coated pits and internalization in coated vesicles. Gold was later visualized in uncoated cytoplasmic vesicles, corresponding to early endosomes and multivesicular bodies (MVBs) or late endosomes. In several instances, localized regions of the limiting membrane of the MVBs appeared coated, a feature of endosomal membranes not previously described. After RME at the apical PM and passage through the endosomal system, the greater part of both insulin- and LDL-gold conjugates was seen to accumulate in large lysosome-like compartments. However, a small but significant proportion of the internalized ligands was transcytosed and released as discrete membrane-associated quanta at the basal cell surface. The uptake of LDL gold was greatly increased in highly vacuolated, late-passage RVECs. In controls, anti-insulin receptor antibody and excess unconjugated insulin caused up to 89% inhibition in gold-insulin binding and internalization. These results illustrate the internalization and intracellular

  10. Transcription factor 7-like 2 gene links increased in vivo insulin synthesis to type 2 diabetes

    NARCIS (Netherlands)

    S. Jainandunsing (Sjaam); Koole, H.R. (H. Rita); van Miert, J.N.I. (Joram N.I.); T. Rietveld (Trinet); J.L.D. Wattimena (Josias); E.J.G. Sijbrands (Eric); F.W.M. de Rooij (Felix)

    2018-01-01

    textabstractTranscription factor 7-like 2 (TCF7L2) is the main susceptibility gene for type 2 diabetes, primarily through impairing the insulin secretion by pancreatic β cells. However, the exact in vivo mechanisms remain poorly understood. We performed a family study and determined if the T risk

  11. Variable liver fat concentration as a proxy for body fat mobilization postpartum has minor effects on insulin-induced changes in hepatic gene expression related to energy metabolism in dairy cows.

    Science.gov (United States)

    Weber, C; Schäff, C T; Kautzsch, U; Börner, S; Erdmann, S; Bruckmaier, R M; Röntgen, M; Kuhla, B; Hammon, H M

    2017-02-01

    The liver plays a central role in adaptation for energy requirements around calving, and changes in the effects of insulin on hepatic energy metabolism contribute to metabolic adaptation in dairy cows. Hepatic insulin effects may depend on body fat mobilization. The objective of this study was to investigate the effects of insulin on the hepatic gene expression of enzymes involved in energy metabolism and factors related to nutrition partitioning in cows with high and low total liver fat concentration (LFC) after calving. Holstein cows were retrospectively grouped according to their LFC after calving as a proxy for body fat mobilization. Cows were classified as low (LLFC; LFC 24.4% fat/dry matter; n = 10) fat-mobilizing after calving. Euglycemic-hyperinsulinemic clamps [6 mU/(kg × min) of insulin for 6 h] were performed in wk 5 antepartum (ap) and wk 3 postpartum (pp). Before and at the end of the euglycemic-hyperinsulinemic clamps, liver biopsies were taken to measure the mRNA abundance of enzymes involved in carbohydrate and lipid metabolism, expression related to the somatotropic axis, and adrenergic and glucocorticoid receptors. The mRNA abundance of pyruvate carboxylase, cytosolic phosphoenolpyruvate carboxykinase (PEPCK; PCK1), acyl-CoA-dehydrogenase very long chain (ACADVL), and hydroxyl-methyl-glutaryl-CoA-synthase 1 increased, but the mRNA abundance of solute carrier family 2 (SLC2A2 and SLC2A4), growth hormone receptor 1A (GHR1A), insulin-like growth factor 1 (IGF1), sterol regulatory element binding factor 1, adrenoceptor α 1A, and glucocorticoid receptor decreased from ap to pp. Insulin treatment was associated with decreased PCK1, mitochondrial PEPCK, glucose-6-phosphatase, propionyl-CoA-carboxylase α, carnitine-palmitoyl-transferase 1A, ACADVL, and insulin receptor mRNA, but increased IGF1 and SLC2A4 mRNA ap and pp and GHR1A mRNA pp. The mRNA abundance of SLC2A4 was greater, and the mRNA abundance of GHR1A and IGF1 tended to be lower in LLFC than

  12. Nuclear orphan receptor TLX affects gene expression, proliferation and cell apoptosis in beta cells.

    Science.gov (United States)

    Shi, Xiaoli; Xiong, Xiaokan; Dai, Zhe; Deng, Haohua; Sun, Li; Hu, Xuemei; Zhou, Feng; Xu, Yancheng

    Nuclear orphan receptor TLX is an essential regulator of the growth of neural stem cells. However, its exact function in pancreatic islet cells is still unknown. In the present study, gene expression profiling analysis revealed that overexpression of TLX in beta cell line MIN6 causes suppression of 176 genes and upregulation of 49 genes, including a cadre of cell cycle, cell proliferation and cell death control genes, such as Btg2, Ddit3 and Gadd45a. We next examined the effects of TLX overexpression on proliferation, apoptosis and insulin secretion in MIN6 cells. Proliferation analysis using EdU assay showed that overexpression of TLX increased percentage of EdU-positive cells. Cell cycle and apoptosis analysis revealed that overexpression of TLX in MIN6 cells resulted in higher percentage of cells exiting G1 into S-phase, and a 58.8% decrease of cell apoptosis induced by 0.5 mM palmitate. Moreover, TLX overexpression did not cause impairment of insulin secretion. Together, we conclude that TLX is among factors capable of controlling beta cell proliferation and survival, which may serve as a target for the development of novel therapies for diabetes. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. Insulin stimulates the expression of the SHARP-1 gene via multiple signaling pathways.

    Science.gov (United States)

    Takagi, K; Asano, K; Haneishi, A; Ono, M; Komatsu, Y; Yamamoto, T; Tanaka, T; Ueno, H; Ogawa, W; Tomita, K; Noguchi, T; Yamada, K

    2014-06-01

    The rat enhancer of split- and hairy-related protein-1 (SHARP-1) is a basic helix-loop-helix transcription factor. An issue of whether SHARP-1 is an insulin-inducible transcription factor was examined. Insulin rapidly increased the level of SHARP-1 mRNA both in vivo and in vitro. Then, signaling pathways involved with the increase of SHARP-1 mRNA by insulin were determined in H4IIE rat hepatoma cells. Pretreatments with LY294002, wortmannin, and staurosporine completely blocked the induction effect, suggesting the involvement of both phosphoinositide 3-kinase (PI 3-K) and protein kinase C (PKC) pathways. In fact, overexpression of a dominant negative form of atypical protein kinase C lambda (aPKCλ) significantly decreased the induction of the SHARP-1 mRNA. In addition, inhibitors for the small GTPase Rac or Jun N-terminal kinase (JNK) also blocked the induction of SHARP-1 mRNA by insulin. Overexpression of a dominant negative form of Rac1 prevented the activation by insulin. Furthermore, actinomycin D and cycloheximide completely blocked the induction of SHARP-1 mRNA by insulin. Finally, when a SHARP-1 expression plasmid was transiently transfected with various reporter plasmids into H4IIE cells, the promoter activity of PEPCK reporter plasmid was specifically decreased. Thus, we conclude that insulin induces the SHARP-1 gene expression at the transcription level via a both PI 3-K/aPKCλ/JNK- and a PI 3-K/Rac/JNK-signaling pathway; protein synthesis is required for this induction; and that SHARP-1 is a potential repressor of the PEPCK gene expression. © Georg Thieme Verlag KG Stuttgart · New York.

  14. Characteristics of the mouse genomic histamine H1 receptor gene

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Isao; Taniuchi, Ichiro; Kitamura, Daisuke [Kyushu Univ., Fukuoka (Japan)] [and others

    1996-08-15

    We report here the molecular cloning of a mouse histamine H1 receptor gene. The protein deduced from the nucleotide sequence is composed of 488 amino acid residues with characteristic properties of GTP binding protein-coupled receptors. Our results suggest that the mouse histamine H1 receptor gene is a single locus, and no related sequences were detected. Interspecific backcross analysis indicated that the mouse histamine H1 receptor gene (Hrh1) is located in the central region of mouse Chromosome 6 linked to microphthalmia (Mitfmi), ras-related fibrosarcoma oncogene 1 (Raf1), and ret proto-oncogene (Ret) in a region of homology with human chromosome 3p. 12 refs., 3 figs.

  15. [Solid state isotope hydrogen exchange for deuterium and tritium in human gene-engineered insulin].

    Science.gov (United States)

    Zolotarev, Yu A; Dadayan, A K; Kozik, V S; Gasanov, E V; Nazimov, I V; Ziganshin, R Kh; Vaskovsky, B V; Murashov, A N; Ksenofontov, A L; Haribin, O N; Nikolaev, E N; Myasoedov, N F

    2014-01-01

    The reaction of high temperature solid state catalytic isotope exchange in peptides and proteins under the action of catalyst-activated spillover hydrogen was studied. The reaction of human gene-engineered insulin with deuterium and tritium was conducted at 120-140° C to produce insulin samples containing 2-6 hydrogen isotope atoms. To determine the distribution of the isotope label over tritium-labeled insulin's amino acid residues, oxidation of the S-S bonds of insulin by performic acid was performed and polypeptide chains isolated; then their acid hydrolysis, amino acid analysis and liquid scintillation counts of tritium in the amino acids were conducted. The isotope label was shown to be incorporated in all amino acids of the protein, with the peptide fragment FVNQHLCGSHLVE of the insulin β-chain showing the largest incorporation. About 45% of the total protein isotope label was incorporated in His5 and His10 of this fragment. For the analysis of isotope label distribution in labeled insulin's peptide fragments, the recovery of the S-S bonds by mercaptoethanol, the enzymatic hydrolysis by glutamyl endopeptidase from Bacillus intermedius and HPLC division of the resulting peptides were carried out. Attribution of the peptide fragments formed due to hydrolysis at the Glu-X bond in the β-chain was accomplished by mass spectrometry. Mass spectrometry analysis data of the deuterium-labeled insulin samples' isotopomeric composition showed that the studied solid state isotope exchange reaction equally involved all the protein molecules. Biological studying of tritium-labeled insulin showed its physiological activity to be completely retained.

  16. Interleukin 18 receptor 1 gene polymorphisms are associated with asthma

    DEFF Research Database (Denmark)

    Zhu, Guohua; Whyte, Moira K B; Vestbo, Jørgen

    2008-01-01

    The interleukin 18 receptor (IL18R1) gene is a strong candidate gene for asthma. It has been implicated in the pathophysiology of asthma and maps to an asthma susceptibility locus on chromosome 2q12. The possibility of association between polymorphisms in IL18R1 and asthma was examined by genotyp...

  17. Vitamin D receptor gene variants in Parkinson's disease patients ...

    African Journals Online (AJOL)

    Background: Vitamin D plays an important role in neurodegenerative disorders as a crucial neuro-immunomodulator. Accumulating data provide evidences that vitamin D receptor (VDR) gene is a candidate gene for susceptibility to Parkinson's disease (PD). Aim: To find out whether the risk of the development of sporadic ...

  18. Activation of transmembrane bile acid receptor TGR5 stimulates insulin secretion in pancreatic {beta} cells

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Divya P.; Rajagopal, Senthilkumar; Mahavadi, Sunila [Department of Physiology and Biophysics, Virginia Commonwealth University School of Medicine, Richmond, VA (United States); Mirshahi, Faridoddin [Division of Gastroenterology, Hepatology and Nutrition, Department of Internal Medicine, Virginia Commonwealth University School of Medicine, Richmond, VA (United States); Grider, John R. [Department of Physiology and Biophysics, Virginia Commonwealth University School of Medicine, Richmond, VA (United States); Murthy, Karnam S., E-mail: skarnam@vcu.edu [Department of Physiology and Biophysics, Virginia Commonwealth University School of Medicine, Richmond, VA (United States); Sanyal, Arun J., E-mail: asanyal@mcvh-vcu.edu [Division of Gastroenterology, Hepatology and Nutrition, Department of Internal Medicine, Virginia Commonwealth University School of Medicine, Richmond, VA (United States)

    2012-10-26

    Highlights: Black-Right-Pointing-Pointer G protein coupled receptor TGR5 is expressed in mouse and human islets. Black-Right-Pointing-Pointer TGR5 is coupled to activation of Gs and Ca{sup 2+} release via cAMP/Epac/PLC-{epsilon} pathway. Black-Right-Pointing-Pointer Activation of TGR5 by bile salts and selective ligands causes insulin secretion. Black-Right-Pointing-Pointer TGR5 could be a potential therapeutic target to treat diabetes. -- Abstract: Bile acids act as signaling molecules and stimulate the G protein coupled receptor, TGR5, in addition to nuclear farnesoid X receptor to regulate lipid, glucose and energy metabolism. Bile acid induced activation of TGR5 in the enteroendocrine cells promotes glucagon like peptide-1 (GLP-1) release, which has insulinotropic effect in the pancreatic {beta} cells. In the present study, we have identified the expression of TGR5 in pancreatic {beta} cell line MIN6 and also in mouse and human pancreatic islets. TGR5 selective ligands, oleanolic acid (OA) and INT-777 selectively activated G{alpha}{sub s} and caused an increase in intracellular cAMP and Ca{sup 2+}. OA and INT-777 also increased phosphoinositide (PI) hydrolysis and the increase was blocked by NF449 (a selective G{alpha}{sub s} inhibitor) or (U73122) (PI hydrolysis inhibitor). OA, INT-777 and lithocholic acid increased insulin release in MIN6 and human islets and the increase was inhibited by treatment with NF449, (U73122) or BAPTA-AM (chelator of calcium), but not with myristoylated PKI (PKA inhibitor), suggesting that the release is dependent on G{sub s}/cAMP/Ca{sup 2+} pathway. 8-pCPT-2 Prime -O-Me-cAMP, a cAMP analog, which activates Epac, but not PKA also stimulated PI hydrolysis. In conclusion, our study demonstrates that the TGR5 expressed in the pancreatic {beta} cells regulates insulin secretion and highlights the importance of ongoing therapeutic strategies targeting TGR5 in the control of glucose homeostasis.

  19. Advanced Glycation End-Products affect transcription factors regulating insulin gene expression

    International Nuclear Information System (INIS)

    Puddu, A.; Storace, D.; Odetti, P.; Viviani, G.L.

    2010-01-01

    Advanced Glycation End-Products (AGEs) are generated by the covalent interaction of reducing sugars with proteins, lipids or nucleic acids. AGEs are implicated in diabetic complications and pancreatic β-cell dysfunction. We previously demonstrated that exposure of the pancreatic islet cell line HIT-T15 to high concentrations of AGEs leads to a significant decrease of insulin secretion and content. Insulin gene transcription is positively regulated by the beta cell specific transcription factor PDX-1 (Pancreatic and Duodenal Homeobox-1). On the contrary, the forkhead transcription factor FoxO1 inhibits PDX-1 gene transcription. Activity of FoxO1 is regulated by post-translational modifications: phosphorylation deactivates FoxO1, and acetylation prevents FoxO1 ubiquitination. In this work we investigated whether AGEs affect expression and subcellular localization of PDX-1 and FoxO1. HIT-T15 cells were cultured for 5 days in presence of AGEs. Cells were then lysed and processed for subcellular fractionation. We determined intracellular insulin content, then we assessed the expression and subcellular localization of PDX-1, FoxO1, phosphoFoxO1 and acetylFoxO1. As expected intracellular insulin content was lower in HIT-T15 cells cultured with AGEs. The results showed that AGEs decreased expression and nuclear localization of PDX-1, reduced phosphorylation of FoxO1, and increased expression and acetylation of FoxO1. These results suggest that AGEs decrease insulin content unbalancing transcription factors regulating insulin gene expression.

  20. Hormonal control of spermatogenesis: expression of FSJH receptor and androgen receptor genes

    NARCIS (Netherlands)

    L.J. Blok (Leen)

    1992-01-01

    textabstractFSH and testosterone are the main hormonal regulators of spermatogenesis. The actions of androgens and FSH are mediated by their respective receptors. Receptor gene expression (mRNA and protein). is an important determinant of hormone action. Biochemical aspects of the regulation of

  1. Divergent effects of insulin-like growth factor-1 receptor expression on prognosis of estrogen receptor positive versus triple negative invasive ductal breast carcinoma

    NARCIS (Netherlands)

    Hartog, Hermien; Horlings, Hugo M; van der Vegt, Bert; Kreike, Bas; Ajouaou, Abderrahim; van de Vijver, Marc J; Boezen, Hendrika; de Bock, Geertruida H; van der Graaf, Wilhelmina; Wesseling, Jelle

    2011-01-01

    The insulin-like growth factor type 1 receptor (IGF1R) is involved in progression of breast cancer and resistance to systemic treatment. Targeting IGF1R signaling may, therefore, be beneficial in systemic treatment. We report the effect of IGF1R expression on prognosis in invasive ductal breast

  2. Receptors for insulin-like growth factor II (IGF-II) in the rat kidney glomerulus

    International Nuclear Information System (INIS)

    Haskell, J.F.; Pillion, D.J.; Meezan, E.

    1986-01-01

    Renal glomeruli were isolated by a technique involving renal perfusion with a solution containing magnetic iron oxide particles, followed by homogenization, sieving and isolation over a strong magnet. Isolated glomeruli were treated with 1% Triton X-100 to solubilize plasma membrane components while insoluble basement membrane components were removed by centrifugation. [ 125 I]Insulin-like growth factor-II (IGF-II) binding to this preparation was competitively inhibited by increasing amounts of unlabelled IGF-II, with 50% inhibition of binding observed at an IGF-II concentration of 1 ng/ml. [ 125 I]IGF-II was covalently cross-linked to its receptor with disuccinimidyl suberate in two tissues known to contain IGF-II receptors, the rat chondrosarcoma chondrocyte and the rat kidney tubule, as well as in rat renal glomeruli. In all three cases, a specific high-molecular weight (Mr = 255,000) band could be identified on autoradiograms of dodecyl sulfate polyacrylamide gels. These results indicate that the rat glomerulus contains a high-affinity receptor for IGF-II. This finding is consistent with the hypothesis that IGF-II plays a role in glomerular growth and differentiation

  3. Specific, high affinity receptors for insulin-like growth factor II in the rat kidney glomerulus

    International Nuclear Information System (INIS)

    Haskell, J.F.; Pillion, D.J.; Meezan, E.

    1988-01-01

    Rat renal glomeruli were isolated by a technique involving kidney perfusion with a solution containing magnetic iron oxide particles, followed by homogenization, sieving, and concentration over a strong magnet. Isolated glomeruli were treated with 1% Triton X-100 to solubilize plasma membrane components, while insoluble basement membrane components were removed by centrifugation. [ 125 I]Insulin-like growth factor II (IGF-II) binding to this preparation was competitively inhibited by increasing amounts of unlabeled IGF-II, with 50% inhibition at an IGF-II concentration of 1 ng/ml. [ 125 I]IGF-II was covalently cross-linked with disuccinimidyl suberate to its receptor in rat renal glomeruli and a specific high mol wt (255,000) band could be identified on autoradiograms of dodecyl sulfate-polyacrylamide gels. [ 125 I]IGF-II binding and cross-linking to this band was inhibited by a polyclonal antibody against the type II IGF receptor. These results demonstrate for the first time that the isolated rat renal glomerulus contains a high affinity receptor for IGF-II

  4. Identification of a growth hormone-responsive STAT5-binding element in the rat insulin 1 gene

    DEFF Research Database (Denmark)

    Galsgaard, E D; Gouilleux, F; Groner, B

    1996-01-01

    promoter activity 2-fold, and this stimulation was abolished by introduction of a block mutation in a gamma-interferon-activated sequence (GAS)-like element (GLE) with the sequence 5'-TTCTGGGAA-3' located in the rat insulin 1 enhancer at position -330 to -322. This element, termed Ins-GLE, was able...... transfected with STAT5 and GH receptor cDNAs, it was found that expression of STAT5 was necessary for GH induction of these two DNA-binding complexes. These results suggest that GH stimulates insulin 1 promoter activity by inducing the binding of STAT5 to Ins-GLE.......GH and PRL stimulate both proliferation and insulin production in pancreatic beta-cells as well as in the rat insulinoma cell line RIN-5AH, We report here that human GH increases insulin mRNA levels in RIN-5AH cells via both somatogenic and lactogenic receptors. GH stimulated the rat insulin 1...

  5. Evidence for an indirect transcriptional regulation of glucose-6-phosphatase gene expression by liver X receptors

    International Nuclear Information System (INIS)

    Grempler, Rolf; Guenther, Susanne; Steffensen, Knut R.; Nilsson, Maria; Barthel, Andreas; Schmoll, Dieter; Walther, Reinhard

    2005-01-01

    Liver X receptor (LXR) paralogues α and β (LXRα and LXRβ) are members of the nuclear hormone receptor family and have oxysterols as endogenous ligands. LXR activation reduces hepatic glucose production in vivo through the inhibition of transcription of the key gluconeogenic enzymes phosphoenolpyruvate carboxykinase and glucose-6-phosphatase (G6Pase). In the present study, we investigated the molecular mechanisms involved in the regulation of G6Pase gene expression by LXR. Both T0901317, a synthetic LXR agonist, and the adenoviral overexpression of either LXRα or LXRβ suppressed G6Pase gene expression in H4IIE hepatoma cells. However, compared to the suppression of G6Pase expression seen by insulin, the decrease of G6Pase mRNA by LXR activation was delayed and was blocked by cycloheximide, an inhibitor of protein synthesis. These observations, together with the absence of a conserved LXR-binding element within the G6Pase promoter, suggest an indirect inhibition of G6Pase gene expression by liver X receptors

  6. Identification and transcriptional modulation of the largemouth bass, Micropterus salmoides, vitellogenin receptor during oocyte development by insulin and sex steroids.

    Science.gov (United States)

    Dominguez, Gustavo A; Quattro, Joseph M; Denslow, Nancy D; Kroll, Kevin J; Prucha, Melinda S; Porak, Wesley F; Grier, Harry J; Sabo-Attwood, Tara L

    2012-09-01

    Fish vitellogenin synthesized and released from the liver of oviparous animals is taken up into oocytes by the vitellogenin receptor. This is an essential process in providing nutrient yolk to developing embryos to ensure successful reproduction. Here we disclose the full length vtgr cDNA sequence for largemouth bass (LMB) that reveals greater than 90% sequence homology with other fish vtgr sequences. We classify LMB Vtgr as a member of the low density lipoprotein receptor superfamily based on conserved domains and categorize as the short variant that is devoid of the O-glycan segment. Phylogenetic analysis places LMB Vtgr sequence into a well-supported monophyletic group of fish Vtgr. Real-time PCR showed that the greatest levels of LMB vtgr mRNA expression occurred in previtellogenic ovarian tissues. In addition, we reveal the effects of insulin, 17beta-estradiol (E(2)), and 11-ketotestosterone (11-KT) in modulation of vtgr, esr, and ar mRNAs in previtellogenic oocytes. Insulin increased vtgr expression levels in follicles ex vivo while exposure to E(2) or 11-KT did not result in modulation of expression. However, both steroids were able to repress insulin-induced vtgr transcript levels. Coexposure with insulin and E(2) or of insulin and 11-KT increased ovarian esr2b and ar mRNA levels, respectively, which suggest a role for these nuclear receptors in insulin-mediated signaling pathways. These data provide the first evidence for the ordered stage-specific expression of LMB vtgr during the normal reproductive process and the hormonal influence of insulin and sex steroids on controlling vtgr transcript levels in ovarian tissues.

  7. Expression of transient receptor potential ankyrin 1 (TRPA1 and its role in insulin release from rat pancreatic beta cells.

    Directory of Open Access Journals (Sweden)

    De-Shou Cao

    Full Text Available Several transient receptor potential (TRP channels are expressed in pancreatic beta cells and have been proposed to be involved in insulin secretion. However, the endogenous ligands for these channels are far from clear. Here, we demonstrate the expression of the transient receptor potential ankyrin 1 (TRPA1 ion channel in the pancreatic beta cells and its role in insulin release. TRPA1 is an attractive candidate for inducing insulin release because it is calcium permeable and is activated by molecules that are produced during oxidative glycolysis.Immunohistochemistry, RT-PCR, and Western blot techniques were used to determine the expression of TRPA1 channel. Ca²⁺ fluorescence imaging and electrophysiology (voltage- and current-clamp techniques were used to study the channel properties. TRPA1-mediated insulin release was determined using ELISA.TRPA1 is abundantly expressed in a rat pancreatic beta cell line and freshly isolated rat pancreatic beta cells, but not in pancreatic alpha cells. Activation of TRPA1 by allyl isothiocyanate (AITC, hydrogen peroxide (H₂O₂, 4-hydroxynonenal (4-HNE, and cyclopentenone prostaglandins (PGJ₂ and a novel agonist methylglyoxal (MG induces membrane current, depolarization, and Ca²⁺ influx leading to generation of action potentials in a pancreatic beta cell line and primary cultured pancreatic beta cells. Activation of TRPA1 by agonists stimulates insulin release in pancreatic beta cells that can be inhibited by TRPA1 antagonists such as HC030031 or AP-18 and by RNA interference. TRPA1-mediated insulin release is also observed in conditions of voltage-gated Na⁺ and Ca²⁺ channel blockade as well as ATP sensitive potassium (K(ATP channel activation.We propose that endogenous and exogenous ligands of TRPA1 cause Ca²⁺ influx and induce basal insulin release and that TRPA1-mediated depolarization acts synergistically with K(ATP channel blockade to facilitate insulin release.

  8. Dopamine receptor gene expression by enkephalin neurons in rat forebrain

    International Nuclear Information System (INIS)

    Le Moine, C.; Normand, E.; Guitteny, A.F.; Fouque, B.; Teoule, R.; Bloch, B.

    1990-01-01

    In situ hybridization experiments were performed with brain sections from normal, control and haloperidol-treated rats to identify and map the cells expressing the D2 dopamine receptor gene. D2 receptor mRNA was detected with radioactive or biotinylated oligonucleotide probes. D2 receptor mRNA was present in glandular cells of the pituitary intermediate lobe and in neurons of the substantia nigra, ventral tegmental area, and forebrain, especially in caudate putamen, nucleus accumbens, olfactory tubercle, and piriform cortex. Hybridization with D2 and preproenkephalin A probes in adjacent sections, as well as combined hybridization with the two probes in the same sections, demonstrated that all detectable enkephalin neurons in the striatum contained the D2 receptor mRNA. Large neurons in caudate putamen, which were unlabeled with the preproenkephalin A probe and which may have been cholinergic, also expressed the D2 receptor gene. Haloperidol treatment (14 or 21 days) provoked an increase in mRNA content for D2 receptor and preproenkephalin A in the striatum. This suggests that the increase in D2 receptor number observed after haloperidol treatment is due to increased activity of the D2 gene. These results indicate that in the striatum, the enkephalin neurons are direct targets for dopamine liberated from mesostriatal neurons

  9. Dopamine receptor gene expression by enkephalin neurons in rat forebrain

    Energy Technology Data Exchange (ETDEWEB)

    Le Moine, C.; Normand, E.; Guitteny, A.F.; Fouque, B.; Teoule, R.; Bloch, B. (Universite de Bordeaux II (France))

    1990-01-01

    In situ hybridization experiments were performed with brain sections from normal, control and haloperidol-treated rats to identify and map the cells expressing the D2 dopamine receptor gene. D2 receptor mRNA was detected with radioactive or biotinylated oligonucleotide probes. D2 receptor mRNA was present in glandular cells of the pituitary intermediate lobe and in neurons of the substantia nigra, ventral tegmental area, and forebrain, especially in caudate putamen, nucleus accumbens, olfactory tubercle, and piriform cortex. Hybridization with D2 and preproenkephalin A probes in adjacent sections, as well as combined hybridization with the two probes in the same sections, demonstrated that all detectable enkephalin neurons in the striatum contained the D2 receptor mRNA. Large neurons in caudate putamen, which were unlabeled with the preproenkephalin A probe and which may have been cholinergic, also expressed the D2 receptor gene. Haloperidol treatment (14 or 21 days) provoked an increase in mRNA content for D2 receptor and preproenkephalin A in the striatum. This suggests that the increase in D2 receptor number observed after haloperidol treatment is due to increased activity of the D2 gene. These results indicate that in the striatum, the enkephalin neurons are direct targets for dopamine liberated from mesostriatal neurons.

  10. PTPIP51: A New Interaction Partner of the Insulin Receptor and PKA in Adipose Tissue

    Directory of Open Access Journals (Sweden)

    M. A. Bobrich

    2013-01-01

    Full Text Available Aims. Our previous experiments revealed an association of PTPIP51 (protein tyrosine phosphatase interacting protein 51 with the insulin signalling pathway through PTP1B and 14-3-3beta. We aimed to clarify the role of PTPIP51 in adipocyte metabolism. Methods. Four groups of ten C57Bl/6 mice each were used. Two groups were fed a standard diet; two groups were fed a high-fat diet. Two groups (one high-fat diet and one standard diet were submitted to endurance training, while the remaining two groups served as untrained control groups. After ten weeks, we measured glucose tolerance of the mice. Adipose tissue samples were analyzed by immunofluorescence and Duolink proximity ligation assay to quantify interactions of PTPIP51 with either insulin receptor (IR or PKA. Results. PTPIP51 and the IR and PTPIP51 and PKA, respectively, were colocalized in all groups. Standard diet animals that were submitted to endurance training showed low PTPIP51-IR and PTPIP51-PKA interactions. The interaction levels of both the IR and PKA differed between the feeding and training groups. Conclusion. PTPIP51 might serve as a linking protein in adipocyte metabolism by connecting the IR-triggered lipogenesis with the PKA-dependent lipolysis. PTPIP51 interacts with both proteins, therefore being a potential gateway for the cooperation of both pathways.

  11. Identification of the bioactive and consensus peptide motif from Momordica charantia insulin receptor-binding protein.

    Science.gov (United States)

    Lo, Hsin-Yi; Li, Chia-Cheng; Ho, Tin-Yun; Hsiang, Chien-Yun

    2016-08-01

    Many food bioactive peptides with diverse functions have been discovered by studying plant proteins. We have previously identified a 68-residue insulin receptor (IR)-binding protein (mcIRBP) from Momordica charantia that exhibits hypoglycemic effects in mice via interaction with IR. By in vitro digestion, we found that mcIRBP-19, spanning residues 50-68 of mcIRBP, enhanced the binding of insulin to IR, stimulated the phosphorylation of PDK1 and Akt, induced the expression of glucose transporter 4, and stimulated both the uptake of glucose in cells and the clearance of glucose in diabetic mice. Furthermore, mcIRBP-19 homologs were present in various plants and shared similar β-hairpin structures and IR kinase-activating abilities to mcIRBP-19. In conclusion, our findings suggested that mcIRBP-19 is a blood glucose-lowering bioactive peptide that exhibits IR-binding potentials. Moreover, we newly identified novel IR-binding bioactive peptides in various plants which belonged to different taxonomic families. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Independent signaling by Drosophila insulin receptor for axon guidance and growth

    Directory of Open Access Journals (Sweden)

    Caroline Rita Li

    2014-01-01

    Full Text Available The Drosophila insulin receptor (DInR regulates a diverse array of biological processes including growth, axon guidance, and sugar homeostasis. Growth regulation by DInR is mediated by Chico, the Drosophila homolog of vertebrate insulin-receptor-substrate proteins IRS1-4. In contrast, DInR regulation of photoreceptor axon guidance in the developing visual system is mediated by the SH2-SH3 domain adaptor protein Dreadlocks (Dock. In vitro studies by others identified five NPXY motifs, one in the juxtamembrane region and four in the signaling C-terminal tail (C-tail, important for interaction with Chico. Here we used yeast two-hybrid assays to identify regions in the DInR C-tail that interact with Dock. These Dock-binding sites were in separate portions of the C-tail from the previously identified Chico-binding sites. To test whether these sites are required for growth or axon guidance in whole animals, a panel of DInR proteins, in which the putative Chico and Dock interaction sites had been mutated individually or in combination, were tested for their ability to rescue viability, growth, and axon guidance defects of dinr mutant flies. Sites required for viability were identified. Unexpectedly, mutation of both putative Dock binding sites, either individually or in combination, did not lead to defects in photoreceptor axon guidance. Thus, either sites also required for viability are necessary for DInR function in axon guidance and/or there is redundancy built into the DInR/Dock interaction such that Dock is able to interact with multiple regions of DInR. We also found that simultaneous mutation of all 5 NPXY motifs implicated in Chico interaction drastically decreased growth in both male and female adult flies. Mutation of these 5 NPXY motifs did not affect photoreceptor axon guidance, showing that different sites within DInR control growth and axon guidance.

  13. Association between haptoglobin gene and insulin resistance in Arab-Americans.

    Science.gov (United States)

    Burghardt, Kyle J; Masri, Dana El; Dass, Sabrina E; Shikwana, Sara S; Jaber, Linda A

    2017-11-01

    To analyze associations between variation in the HP gene and lipid and glucose-related measures in Arab-Americans. Secondary analyses were performed based on sex. Genomic DNA was extracted from samples obtained from a previous epidemiological study of diabetes in Arab-Americans. The HP 1 and 2 alleles were analyzed by polymerase chain reaction and gel electrophoresis. Associations were analyzed by linear regression. Associations were identified between the heterozygous haptoglobin 2-1 genotype and insulin resistance, fasting insulin and fasting c-peptide. The effect of sex did not remain significant after adjustment for relevant variables. HP genetic variation may have utility as a biomarker of insulin resistance and diabetes risk in Arab-Americans, however, future prospective studies are needed.

  14. Fixed ratio combinations of glucagon like peptide 1 receptor agonists with basal insulin: a systematic review and meta-analysis.

    Science.gov (United States)

    Liakopoulou, Paraskevi; Liakos, Aris; Vasilakou, Despoina; Athanasiadou, Eleni; Bekiari, Eleni; Kazakos, Kyriakos; Tsapas, Apostolos

    2017-06-01

    Basal insulin controls primarily fasting plasma glucose but causes hypoglycaemia and weight gain, whilst glucagon like peptide 1 receptor agonists induce weight loss without increasing risk for hypoglycaemia. We conducted a systematic review and meta-analysis of randomised controlled trials to investigate the efficacy and safety of fixed ratio combinations of basal insulin with glucagon like peptide 1 receptor agonists. We searched Medline, Embase, and the Cochrane Library as well as conference abstracts up to December 2016. We assessed change in haemoglobin A 1c , body weight, and incidence of hypoglycaemia and gastrointestinal adverse events. We included eight studies with 5732 participants in the systematic review. Switch from basal insulin to fixed ratio combinations with a glucagon like peptide 1 receptor agonist was associated with 0.72% reduction in haemoglobin A 1c [95% confidence interval -1.03 to -0.41; I 2  = 93%] and 2.35 kg reduction in body weight (95% confidence interval -3.52 to -1.19; I 2  = 93%), reducing also risk for hypoglycaemia [odds ratio 0.70; 95% confidence interval 0.57 to 0.86; I 2  = 85%] but increasing incidence of nausea (odds ratio 6.89; 95% confidence interval 3.73-12.74; I 2  = 79%). Similarly, switching patients from treatment with a glucagon like peptide 1 receptor agonist to a fixed ratio combination with basal insulin was associated with 0.94% reduction in haemoglobin A 1c (95% confidence interval -1.11 to -0.77) and an increase in body weight by 2.89 kg (95% confidence interval 2.17-3.61). Fixed ratio combinations of basal insulin with glucagon like peptide 1 receptor agonists improve glycaemic control whilst balancing out risk for hypoglycaemia and gastrointestinal side effects.

  15. Endocrine Parameters and Phenotypes of the Growth Hormone Receptor Gene Disrupted (GHR−/−) Mouse

    Science.gov (United States)

    List, Edward O.; Sackmann-Sala, Lucila; Berryman, Darlene E.; Funk, Kevin; Kelder, Bruce; Gosney, Elahu S.; Okada, Shigeru; Ding, Juan; Cruz-Topete, Diana

    2011-01-01

    Disruption of the GH receptor (GHR) gene eliminates GH-induced intracellular signaling and, thus, its biological actions. Therefore, the GHR gene disrupted mouse (GHR−/−) has been and is a valuable tool for helping to define various parameters of GH physiology. Since its creation in 1995, this mouse strain has been used by our laboratory and others for numerous studies ranging from growth to aging. Some of the most notable discoveries are their extreme insulin sensitivity in the presence of obesity. Also, the animals have an extended lifespan, which has generated a large number of investigations into the roles of GH and IGF-I in the aging process. This review summarizes the many results derived from the GHR−/− mice. We have attempted to present the findings in the context of current knowledge regarding GH action and, where applicable, to discuss how these mice compare to GH insensitivity syndrome in humans. PMID:21123740

  16. Influence of reductive diet and physical aerobic training on binding and degradation of 125J-insulin by erythrocyte receptors in children with simple obesity

    International Nuclear Information System (INIS)

    Szczesniak, L.; Rychlewski, T.; Kasprzak, Z.; Banaszak, F.

    1994-01-01

    Insuline resistance, expressed by lower insuline binding by receptors, is related to the obesity. Improvement of the binding was observed together with reduction of body weight and in result of physical exercise. In the work was investigated an influence of complex result of reductive diet at the level of 1300-1500 kcal and systematic half-an-hour aerobic exercise on binding and degradation of 125 J-insulin by erythrocyte receptors in children with simple obesity. The rest binding of insulin by erythrocyte receptors in obese children was compared with the result observed in the children having normal body weight. Results of these researches confirm that systematic physical exercise connected with reductive diet improves the indexes of lipid balance, increases efficiency of the organism, estimated by maximal oxygen absorption, decreases body weight and improves binding of 125 J-insulin to erythrocyte receptors. (authors)

  17. Tissue-specific methylation of human insulin gene and PCR assay for monitoring beta cell death.

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    Mohamed I Husseiny

    Full Text Available The onset of metabolic dysregulation in type 1 diabetes (T1D occurs after autoimmune destruction of the majority of pancreatic insulin-producing beta cells. We previously demonstrated that the DNA encoding the insulin gene is uniquely unmethylated in these cells and then developed a methylation-specific PCR (MSP assay to identify circulating beta cell DNA in streptozotocin-treated mice prior to the rise in blood glucose. The current study extends to autoimmune non-obese diabetic (NOD mice and humans, showing in NOD mice that beta cell death occurs six weeks before the rise in blood sugar and coincides with the onset of islet infiltration by immune cells, demonstrating the utility of MSP for monitoring T1D. We previously reported unique patterns of methylation of the human insulin gene, and now extend this to other human tissues. The methylation patterns of the human insulin promoter, intron 1, exon 2, and intron 2 were determined in several normal human tissues. Similar to our previous report, the human insulin promoter was unmethylated in beta cells, but methylated in all other tissues tested. In contrast, intron 1, exon 2 and intron 2 did not exhibit any tissue-specific DNA methylation pattern. Subsequently, a human MSP assay was developed based on the methylation pattern of the insulin promoter and human islet DNA was successfully detected in circulation of T1D patients after islet transplantation therapy. Signal levels of normal controls and pre-transplant samples were shown to be similar, but increased dramatically after islet transplantation. In plasma the signal declines with time but in whole blood remains elevated for at least two weeks, indicating that association of beta cell DNA with blood cells prolongs the signal. This assay provides an effective method to monitor beta cell destruction in early T1D and in islet transplantation therapy.

  18. Increased prevalence of VNTR III of the insulin gene in women with gestational diabetes mellitus (GDM).

    Science.gov (United States)

    Litou, Hariklia; Anastasiou, Eleni; Thalassinou, Louminitsa; Sarika, Helen-Leda; Philippou, George; Alevizaki, Maria

    2007-05-01

    The VNTR polymorphism in the promoter region of the insulin gene (INS-VNTR) affects transcription rate and has been associated with insulin resistance and DM2. Gestational diabetes mellitus (GDM) is a multifactorial disorder, where both impaired insulin secretion and action may be involved. The aim of the study was to examine the distribution of the INS-VNTRs in women with GDM and to investigate possible associations with features of beta cell function and glycaemic control in this population. One hundred and sixty-one women with GDM and 111 normal pregnant women (n) were genotyped for INS-VNTR during the 24th-32nd pregnancy week. Glucose and insulin levels were determined during the diagnostic OGTT. The majority of the previous GDM women were also examined at 3-6 months post-partum. VNTR class III/III genotype was significantly more frequent in the GDM group 8.7% versus 2.7%, p=0.02 giving an OR of 3.97 (1.1-14.29). An increased frequency of the VNTR class III allele was found in those GDM women who required insulin for treatment compared to those controlled with diet alone (12.4% versus 4%, pwomen homozygous for the class III allele without reaching statistical significance (p=0.09). The INS-VNTR class III is more frequent in women who develop GDM, and may be associated with decreased ability of the beta cell to meet the increased insulin requirements as reflected by the need for insulin supplementation for adequate glycaemic control.

  19. The Mouse Solitary Odorant Receptor Gene Promoters as Models for the Study of Odorant Receptor Gene Choice.

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    Andrea Degl'Innocenti

    Full Text Available In vertebrates, several anatomical regions located within the nasal cavity mediate olfaction. Among these, the main olfactory epithelium detects most conventional odorants. Olfactory sensory neurons, provided with cilia exposed to the air, detect volatile chemicals via an extremely large family of seven-transmembrane chemoreceptors named odorant receptors. Their genes are expressed in a monogenic and monoallelic fashion: a single allele of a single odorant receptor gene is transcribed in a given mature neuron, through a still uncharacterized molecular mechanism known as odorant receptor gene choice.Odorant receptor genes are typically arranged in genomic clusters, but a few are isolated (we call them solitary from the others within a region broader than 1 Mb upstream and downstream with respect to their transcript's coordinates. The study of clustered genes is problematic, because of redundancy and ambiguities in their regulatory elements: we propose to use the solitary genes as simplified models to understand odorant receptor gene choice.Here we define number and identity of the solitary genes in the mouse genome (C57BL/6J, and assess the conservation of the solitary status in some mammalian orthologs. Furthermore, we locate their putative promoters, predict their homeodomain binding sites (commonly present in the promoters of odorant receptor genes and compare candidate promoter sequences with those of wild-caught mice. We also provide expression data from histological sections.In the mouse genome there are eight intact solitary genes: Olfr19 (M12, Olfr49, Olfr266, Olfr267, Olfr370, Olfr371, Olfr466, Olfr1402; five are conserved as solitary in rat. These genes are all expressed in the main olfactory epithelium of three-day-old mice. The C57BL/6J candidate promoter of Olfr370 has considerably varied compared to its wild-type counterpart. Within the putative promoter for Olfr266 a homeodomain binding site is predicted. As a whole, our findings

  20. Brain insulin signaling and Alzheimer's disease: current evidence and future directions.

    Science.gov (United States)

    Schiöth, Helgi B; Craft, Suzanne; Brooks, Samantha J; Frey, William H; Benedict, Christian

    2012-08-01

    Insulin receptors in the brain are found in high densities in the hippocampus, a region that is fundamentally involved in the acquisition, consolidation, and recollection of new information. Using the intranasal method, which effectively bypasses the blood-brain barrier to deliver and target insulin directly from the nose to the brain, a series of experiments involving healthy humans has shown that increased central nervous system (CNS) insulin action enhances learning and memory processes associated with the hippocampus. Since Alzheimer's disease (AD) is linked to CNS insulin resistance, decreased expression of insulin and insulin receptor genes and attenuated permeation of blood-borne insulin across the blood-brain barrier, impaired brain insulin signaling could partially account for the cognitive deficits associated with this disease. Considering that insulin mitigates hippocampal synapse vulnerability to amyloid beta and inhibits the phosphorylation of tau, pharmacological strategies bolstering brain insulin signaling, such as intranasal insulin, could have significant therapeutic potential to deter AD pathogenesis.

  1. Mammary tumors that become independent of the type I insulin-like growth factor receptor express elevated levels of platelet-derived growth factor receptors

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    Campbell Craig I

    2011-11-01

    Full Text Available Abstract Background Targeted therapies are becoming an essential part of breast cancer treatment and agents targeting the type I insulin-like growth factor receptor (IGF-IR are currently being investigated in clinical trials. One of the limitations of targeted therapies is the development of resistant variants and these variants typically present with unique gene expression patterns and characteristics compared to the original tumor. Results MTB-IGFIR transgenic mice, with inducible overexpression of the IGF-IR were used to model mammary tumors that develop resistance to IGF-IR targeting agents. IGF-IR independent mammary tumors, previously shown to possess characteristics associated with EMT, were found to express elevated levels of PDGFRα and PDGFRβ. Furthermore, these receptors were shown to be inversely expressed with the IGF-IR in this model. Using cell lines derived from IGF-IR-independent mammary tumors (from MTB-IGFIR mice, it was demonstrated that PDGFRα and to a lesser extent PDGFRβ was important for cell migration and invasion as RNAi knockdown of PDGFRα alone or PDGFRα and PDGFRβ in combination, significantly decreased tumor cell migration in Boyden chamber assays and suppressed cell migration in scratch wound assays. Somewhat surprisingly, concomitant knockdown of PDGFRα and PDGFRβ resulted in a modest increase in cell proliferation and a decrease in apoptosis. Conclusion During IGF-IR independence, PDGFRs are upregulated and function to enhance tumor cell motility. These results demonstrate a novel interaction between the IGF-IR and PDGFRs and highlight an important, therapeutically relevant pathway, for tumor cell migration and invasion.

  2. Biologic Roles of Estrogen Receptor-β and Insulin-Like Growth Factor-2 in Triple-Negative Breast Cancer

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    Nalo Hamilton

    2015-01-01

    Full Text Available Triple-negative breast cancer (TNBC occurs in 10–15% of patients yet accounts for almost half of all breast cancer deaths. TNBCs lack expression of estrogen and progesterone receptors and HER-2 overexpression and cannot be treated with current targeted therapies. TNBCs often occur in African American and younger women. Although initially responsive to some chemotherapies, TNBCs tend to relapse and metastasize. Thus, it is critical to find new therapeutic targets. A second ER gene product, termed ERβ, in the absence of ERα may be such a target. Using human TNBC specimens with known clinical outcomes to assess ERβ expression, we find that ERβ1 associates with significantly worse 5-year overall survival. Further, a panel of TNBC cell lines exhibit significant levels of ERβ protein. To assess ERβ effects on proliferation, ERβ expression in TNBC cells was silenced using shRNA, resulting in a significant reduction in TNBC proliferation. ERβ-specific antagonists similarly suppressed TNBC growth. Growth-stimulating effects of ERβ may be due in part to downstream actions that promote VEGF, amphiregulin, and Wnt-10b secretion, other factors associated with tumor promotion. In vivo, insulin-like growth factor-2 (IGF-2, along with ERβ1, is significantly expressed in TNBC and stimulates high ERβ mRNA in TNBC cells. This work may help elucidate the interplay of metabolic and growth factors in TNBC.

  3. Vitamin A and feeding statuses modulate the insulin-regulated gene expression in Zucker lean and fatty primary rat hepatocytes.

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    Wei Chen

    Full Text Available Unattended hepatic insulin resistance predisposes individuals to dyslipidemia, type 2 diabetes and many other metabolic complications. The mechanism of hepatic insulin resistance at the gene expression level remains unrevealed. To examine the effects of vitamin A (VA, total energy intake and feeding conditions on the insulin-regulated gene expression in primary hepatocytes of Zucker lean (ZL and fatty (ZF rats, we analyze the expression levels of hepatic model genes in response to the treatments of insulin and retinoic acid (RA. We report that the insulin- and RA-regulated glucokinase, sterol regulatory element-binding protein-1c and cytosolic form of phosphoenolpyruvate carboxykinase expressions are impaired in hepatocytes of ZF rats fed chow or a VA sufficient (VAS diet ad libitum. The impairments are partially corrected when ZF rats are fed a VA deficient (VAD diet ad libitum or pair-fed a VAS diet to the intake of their VAD counterparts in non-fasting conditions. Interestingly in the pair-fed ZL and ZF rats, transient overeating on the last day of pair-feeding regimen changes the expression levels of some VA catabolic genes, and impairs the insulin- and RA-regulated gene expression in hepatocytes. These results demonstrate that VA and feeding statuses modulate the hepatic insulin sensitivity at the gene expression level.

  4. Cinnamon extract regulates glucose transporter and insulin-signaling gene expression in mouse adipocytes.

    Science.gov (United States)

    Cao, Heping; Graves, Donald J; Anderson, Richard A

    2010-11-01

    Cinnamon extracts (CE) are reported to have beneficial effects on people with normal and impaired glucose tolerance, the metabolic syndrome, type 2 diabetes, and insulin resistance. However, clinical results are controversial. Molecular characterization of CE effects is limited. This study investigated the effects of CE on gene expression in cultured mouse adipocytes. Water-soluble CE was prepared from ground cinnamon (Cinnamomum burmannii). Quantitative real-time PCR was used to investigate CE effects on the expression of genes coding for adipokines, glucose transporter (GLUT) family, and insulin-signaling components in mouse 3T3-L1 adipocytes. CE (100 μg/ml) increased GLUT1 mRNA levels 1.91±0.15, 4.39±0.78, and 6.98±2.18-fold of the control after 2-, 4-, and 16-h treatments, respectively. CE decreased the expression of further genes encoding insulin-signaling pathway proteins including GSK3B, IGF1R, IGF2R, and PIK3R1. This study indicates that CE regulates the expression of multiple genes in adipocytes and this regulation could contribute to the potential health benefits of CE. Published by Elsevier GmbH.

  5. Integrated olfactory receptor and microarray gene expression databases

    Directory of Open Access Journals (Sweden)

    Crasto Chiquito J

    2007-06-01

    Full Text Available Abstract Background Gene expression patterns of olfactory receptors (ORs are an important component of the signal encoding mechanism in the olfactory system since they determine the interactions between odorant ligands and sensory neurons. We have developed the Olfactory Receptor Microarray Database (ORMD to house OR gene expression data. ORMD is integrated with the Olfactory Receptor Database (ORDB, which is a key repository of OR gene information. Both databases aim to aid experimental research related to olfaction. Description ORMD is a Web-accessible database that provides a secure data repository for OR microarray experiments. It contains both publicly available and private data; accessing the latter requires authenticated login. The ORMD is designed to allow users to not only deposit gene expression data but also manage their projects/experiments. For example, contributors can choose whether to make their datasets public. For each experiment, users can download the raw data files and view and export the gene expression data. For each OR gene being probed in a microarray experiment, a hyperlink to that gene in ORDB provides access to genomic and proteomic information related to the corresponding olfactory receptor. Individual ORs archived in ORDB are also linked to ORMD, allowing users access to the related microarray gene expression data. Conclusion ORMD serves as a data repository and project management system. It facilitates the study of microarray experiments of gene expression in the olfactory system. In conjunction with ORDB, ORMD integrates gene expression data with the genomic and functional data of ORs, and is thus a useful resource for both olfactory researchers and the public.

  6. Glucose metabolism in pigs expressing human genes under an insulin promoter.

    Science.gov (United States)

    Wijkstrom, Martin; Bottino, Rita; Iwase, Hayoto; Hara, Hidetaka; Ekser, Burcin; van der Windt, Dirk; Long, Cassandra; Toledo, Frederico G S; Phelps, Carol J; Trucco, Massimo; Cooper, David K C; Ayares, David

    2015-01-01

    Xenotransplantation of porcine islets can reverse diabetes in non-human primates. The remaining hurdles for clinical application include safe and effective T-cell-directed immunosuppression, but protection against the innate immune system and coagulation dysfunction may be more difficult to achieve. Islet-targeted genetic manipulation of islet-source pigs represents a powerful tool to protect against graft loss. However, whether these genetic alterations would impair islet function is unknown. On a background of α1,3-galactosyltransferase gene-knockout (GTKO)/human (h)CD46, additional genes (hCD39, human tissue factor pathway inhibitor, porcine CTLA4-Ig) were inserted in different combinations under an insulin promoter to promote expression in islets (confirmed by immunofluorescence). Seven pigs were tested for baseline and glucose/arginine-challenged levels of glucose, insulin, C-peptide, and glucagon. This preliminary study did not show definite evidence of β-cell deficiencies, even when three transgenes were expressed under the insulin promoter. Of seven animals, all were normoglycemic at fasting, and five of seven had normal glucose disposal rates after challenge. All animals exhibited insulin, C-peptide, and glucagon responses to both glucose and arginine challenge; however, significant interindividual variation was observed. Multiple islet-targeted transgenic expression was not associated with an overtly detrimental effect on islet function, suggesting that complex genetic constructs designed for islet protection warrants further testing in islet xenotransplantation models. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  7. Role of aryl hydrocarbon receptor nuclear translocator in KATP channel-mediated insulin secretion in INS-1 insulinoma cells

    International Nuclear Information System (INIS)

    Kim, Ji-Seon; Zheng Haifeng; Kim, Sung Joon; Park, Jong-Wan; Park, Kyong Soo; Ho, Won-Kyung; Chun, Yang-Sook

    2009-01-01

    Aryl hydrocarbon receptor nuclear translocator (ARNT) has been known to participate in cellular responses to xenobiotic and hypoxic stresses, as a common partner of aryl hydrocarbon receptor and hypoxia inducible factor-1/2α. Recently, it was reported that ARNT is essential for adequate insulin secretion in response to glucose input and that its expression is downregulated in the pancreatic islets of diabetic patients. In the present study, the authors addressed the mechanism by which ARNT regulates insulin secretion in the INS-1 insulinoma cell line. In ARNT knock-down cells, basal insulin release was elevated, but insulin secretion was not further stimulated by a high-glucose challenge. Electrophysiological analyses revealed that glucose-dependent membrane depolarization was impaired in these cells. Furthermore, K ATP channel activity and expression were reduced. Of two K ATP channel subunits, Kir6.2 was found to be positively regulated by ARNT at the mRNA and protein levels. Based on these results, the authors suggest that ARNT expresses K ATP channel and by so doing regulates glucose-dependent insulin secretion.

  8. Activation and Regulation of the Pattern Recognition Receptors in Obesity-Induced Adipose Tissue Inflammation and Insulin Resistance

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    Kiyoshi Takatsu

    2013-09-01

    Full Text Available Obesity-associated chronic tissue inflammation is a key contributing factor to type 2 diabetes mellitus, and a number of studies have clearly demonstrated that the immune system and metabolism are highly integrated. Recent advances in deciphering the various immune cells and signaling networks that link the immune and metabolic systems have contributed to our understanding of the pathogenesis of obesity-associated inflammation. Other recent studies have suggested that pattern recognition receptors in the innate immune system recognize various kinds of endogenous and exogenous ligands, and have a crucial role in initiating or promoting obesity-associated chronic inflammation. Importantly, these mediators act on insulin target cells or on insulin-producing cells impairing insulin sensitivity and its secretion. Here, we discuss how various pattern recognition receptors in the immune system underlie the etiology of obesity-associated inflammation and insulin resistance, with a particular focus on the TLR (Toll-like receptor family protein Radioprotective 105 (RP105/myeloid differentiation protein-1 (MD-1.

  9. Activation and regulation of the pattern recognition receptors in obesity-induced adipose tissue inflammation and insulin resistance.

    Science.gov (United States)

    Watanabe, Yasuharu; Nagai, Yoshinori; Takatsu, Kiyoshi

    2013-09-23

    Obesity-associated chronic tissue inflammation is a key contributing factor to type 2 diabetes mellitus, and a number of studies have clearly demonstrated that the immune system and metabolism are highly integrated. Recent advances in deciphering the various immune cells and signaling networks that link the immune and metabolic systems have contributed to our understanding of the pathogenesis of obesity-associated inflammation. Other recent studies have suggested that pattern recognition receptors in the innate immune system recognize various kinds of endogenous and exogenous ligands, and have a crucial role in initiating or promoting obesity-associated chronic inflammation. Importantly, these mediators act on insulin target cells or on insulin-producing cells impairing insulin sensitivity and its secretion. Here, we discuss how various pattern recognition receptors in the immune system underlie the etiology of obesity-associated inflammation and insulin resistance, with a particular focus on the TLR (Toll-like receptor) family protein Radioprotective 105 (RP105)/myeloid differentiation protein-1 (MD-1).

  10. Large-scale studies of the HphI insulin gene variable-number-of-tandem-repeats polymorphism in relation to Type 2 diabetes mellitus and insulin release

    DEFF Research Database (Denmark)

    Hansen, S K; Gjesing, A P; Rasmussen, S K

    2004-01-01

    The class III allele of the variable-number-of-tandem-repeats polymorphism located 5' of the insulin gene (INS-VNTR) has been associated with Type 2 diabetes and altered birthweight. It has also been suggested, although inconsistently, that the class III allele plays a role in glucose-induced ins......The class III allele of the variable-number-of-tandem-repeats polymorphism located 5' of the insulin gene (INS-VNTR) has been associated with Type 2 diabetes and altered birthweight. It has also been suggested, although inconsistently, that the class III allele plays a role in glucose...

  11. Mice lacking the p43 mitochondrial T3 receptor become glucose intolerant and insulin resistant during aging.

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    Christelle Bertrand

    Full Text Available Thyroid hormones (TH play an important regulatory role in energy expenditure regulation and are key regulators of mitochondrial activity. We have previously identified a mitochondrial triiodothyronine (T3 receptor (p43 which acts as a mitochondrial transcription factor of the organelle genome, which leads in vitro and in vivo, to a stimulation of mitochondrial biogenesis. Recently, we generated mice carrying a specific p43 invalidation. At 2 months of age, we reported that p43 depletion in mice induced a major defect in insulin secretion both in vivo and in isolated pancreatic islets, and a loss of glucose-stimulated insulin secretion. The present study was designed to determine whether p43 invalidation influences life expectancy and modulates blood glucose and insulin levels as well as glucose tolerance or insulin sensitivity during aging. We report that from 4 months old onwards, mice lacking p43 are leaner than wild-type mice. p43-/- mice also have a moderate reduction of life expectancy compared to wild type. We found no difference in blood glucose levels, excepted at 24 months old where p43-/- mice showed a strong hyperglycemia in fasting conditions compared to controls animals. However, the loss of glucose-stimulated insulin secretion was maintained whatever the age of mice lacking p43. If up to 12 months old, glucose tolerance remained unchanged, beyond this age p43-/- mice became increasingly glucose intolerant. In addition, if up to 12 months old p43 deficient animals were more sensitive to insulin, after this age we observed a loss of this capacity, culminating in 24 months old mice with a decreased sensitivity to the hormone. In conclusion, we demonstrated that during aging the depletion of the mitochondrial T3 receptor p43 in mice progressively induced an increased glycemia in the fasted state, glucose intolerance and an insulin-resistance several features of type-2 diabetes.

  12. High fructose-mediated attenuation of insulin receptor signaling does not affect PDGF-induced proliferative signaling in vascular smooth muscle cells.

    Science.gov (United States)

    Osman, Islam; Poulose, Ninu; Ganapathy, Vadivel; Segar, Lakshman

    2016-11-15

    Insulin resistance is associated with accelerated atherosclerosis. Although high fructose is known to induce insulin resistance, it remains unclear as to how fructose regulates insulin receptor signaling and proliferative phenotype in vascular smooth muscle cells (VSMCs), which play a major role in atherosclerosis. Using human aortic VSMCs, we investigated the effects of high fructose treatment on insulin receptor substrate-1 (IRS-1) serine phosphorylation, insulin versus platelet-derived growth factor (PDGF)-induced phosphorylation of Akt, S6 ribosomal protein, and extracellular signal-regulated kinase (ERK), and cell cycle proteins. In comparison with PDGF (a potent mitogen), neither fructose nor insulin enhanced VSMC proliferation and cyclin D1 expression. d-[ 14 C(U)]fructose uptake studies revealed a progressive increase in fructose uptake in a time-dependent manner. Concentration-dependent studies with high fructose (5-25mM) showed marked increases in IRS-1 serine phosphorylation, a key adapter protein in insulin receptor signaling. Accordingly, high fructose treatment led to significant diminutions in insulin-induced phosphorylation of downstream signaling components including Akt and S6. In addition, high fructose significantly diminished insulin-induced ERK phosphorylation. Nevertheless, high fructose did not affect PDGF-induced key proliferative signaling events including phosphorylation of Akt, S6, and ERK and expression of cyclin D1 protein. Together, high fructose dysregulates IRS-1 phosphorylation state and proximal insulin receptor signaling in VSMCs, but does not affect PDGF-induced proliferative signaling. These findings suggest that systemic insulin resistance rather than VSMC-specific dysregulation of insulin receptor signaling by high fructose may play a major role in enhancing atherosclerosis and neointimal hyperplasia. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Reduced phosphorylation of brain insulin receptor substrate and Akt proteins in apolipoprotein-E4 targeted replacement mice.

    Science.gov (United States)

    Ong, Qi-Rui; Chan, Elizabeth S; Lim, Mei-Li; Cole, Gregory M; Wong, Boon-Seng

    2014-01-17

    Human ApoE4 accelerates memory decline in ageing and in Alzheimer's disease. Although intranasal insulin can improve cognition, this has little effect in ApoE4 subjects. To understand this ApoE genotype-dependent effect, we examined brain insulin signaling in huApoE3 and huApoE4 targeted replacement (TR) mice. At 32 weeks, lower insulin receptor substrate 1 (IRS1) at S636/639 and Akt phosphorylation at T308 were detected in fasting huApoE4 TR mice as compared to fasting huApoE3 TR mice. These changes in fasting huApoE4 TR mice were linked to lower brain glucose content and have no effect on plasma glucose level. However, at 72 weeks of age, these early changes were accompanied by reduction in IRS2 expression, IRS1 phosphorylation at Y608, Akt phosphorylation at S473, and MAPK (p38 and p44/42) activation in the fasting huApoE4 TR mice. The lower brain glucose was significantly associated with higher brain insulin in the aged huApoE4 TR mice. These results show that ApoE4 reduces brain insulin signaling and glucose level leading to higher insulin content.

  14. Ancestral genomic duplication of the insulin gene in tilapia: An analysis of possible implications for clinical islet xenotransplantation using donor islets from transgenic tilapia expressing a humanized insulin gene.

    Science.gov (United States)

    Hrytsenko, Olga; Pohajdak, Bill; Wright, James R

    2016-07-03

    Tilapia, a teleost fish, have multiple large anatomically discrete islets which are easy to harvest, and when transplanted into diabetic murine recipients, provide normoglycemia and mammalian-like glucose tolerance profiles. Tilapia insulin differs structurally from human insulin which could preclude their use as islet donors for xenotransplantation. Therefore, we produced transgenic tilapia with islets expressing a humanized insulin gene. It is now known that fish genomes may possess an ancestral duplication and so tilapia may have a second insulin gene. Therefore, we cloned, sequenced, and characterized the tilapia insulin 2 transcript and found that its expression is negligible in islets, is not islet-specific, and would not likely need to be silenced in our transgenic fish.

  15. Transgenic Wuzhishan minipigs designed to express a dominant-negative porcine growth hormone receptor display small stature and a perturbed insulin/IGF-1 pathway.

    Science.gov (United States)

    Li, Feida; Li, Yong; Liu, Huan; Zhang, Xingju; Liu, Chuxin; Tian, Kai; Bolund, Lars; Dou, Hongwei; Yang, Wenxian; Yang, Huanming; Staunstrup, Nicklas Heine; Du, Yutao

    2015-12-01

    Growth hormone (GH) is an anabolic mitogen with widespread influence on cellular growth and differentiation as well as on glucose and lipid metabolism. GH binding to the growth hormone receptor (GHR) on hepatocytes prompts expression of insulin growth factor I (IGF-1) involved in nutritionally induced compensatory hyperplasia of pancreatic β-cell islets and insulin release. A prolonged hyperactivity of the IGF-1/insulin axis in the face of insulinotropic nutrition, on the other hand, can lead to collapse of the pancreatic islets and glucose intolerance. Individuals with Laron syndrome carry mutations in the GHR gene resulting in severe congenital IGF-1 deficiency and elevated GH serum levels leading to short stature as well as perturbed lipid and glucose metabolism. However, these individuals enjoy a reduced prevalence of acne, cancer and possibly diabetes. Minipigs have become important biomedical models for human conditions due to similarities in organ anatomy, physiology, and metabolism relative to humans. The purpose of this study was to generate transgenic Wuzhishan minipigs by handmade cloning with impaired systemic GHR activity and assess their growth profile and glucose metabolism. Transgenic minipigs featuring overexpression of a dominant-negative porcine GHR (GHR(dm)) presented postnatal growth retardation and proportionate dwarfism. Molecular changes included elevated GH serum levels and mild hyperglycemia. We believe that this model may prove valuable in the study of GH functions in relation to cancer, diabetes and longevity.

  16. TLR4 and Insulin Resistance

    Directory of Open Access Journals (Sweden)

    Jane J. Kim

    2010-01-01

    Full Text Available Chronic inflammation is a key feature of insulin resistance and obesity. Toll-Like Receptor 4 (TLR4, involved in modulating innate immunity, is an important mediator of insulin resistance and its comorbidities. TLR4 contributes to the development of insulin resistance and inflammation through its activation by elevated exogenous ligands (e.g., dietary fatty acids and enteric lipopolysaccharide and endogenous ligands (e.g., free fatty acids which are elevated in obese states. TLR4, expressed in insulin target tissues, activates proinflammatory kinases JNK, IKK, and p38 that impair insulin signal transduction directly through inhibitory phosphorylation of insulin receptor substrate (IRS on serine residues. TLR4 activation also leads to increased transcription of pro-inflammatory genes, resulting in elevation of cytokine, chemokine, reactive oxygen species, and eicosanoid levels that promote further insulin-desensitization within the target cell itself and in other cells via paracrine and systemic effects. Increased understanding of cell type-specific TLR4-mediated effects on insulin action present the opportunity and challenge of developing related therapeutic approaches for improving insulin sensitivity while preserving innate immunity.

  17. Beta-cell lines derived from transgenic mice expressing a hybrid insulin gene-oncogene

    DEFF Research Database (Denmark)

    Efrat, S; Linde, S; Kofod, Hans

    1988-01-01

    Three pancreatic beta-cell lines have been established from insulinomas derived from transgenic mice carrying a hybrid insulin-promoted simian virus 40 tumor antigen gene. The beta tumor cell (beta TC) lines maintain the features of differentiated beta cells for about 50 passages in culture. The ...... both to immortalize a rare cell type and to provide a selection for the maintenance of its differentiated phenotype....

  18. Insulin utilizes the PI 3-kinase pathway to inhibit SP-A gene expression in lung epithelial cells

    Directory of Open Access Journals (Sweden)

    Snyder Jeanne M

    2002-10-01

    Full Text Available Abstract Background It has been proposed that high insulin levels may cause delayed lung development in the fetuses of diabetic mothers. A key event in lung development is the production of adequate amounts of pulmonary surfactant. Insulin inhibits the expression of surfactant protein A (SP-A, the major surfactant-associated protein, in lung epithelial cells. In the present study, we investigated the signal transduction pathways involved in insulin inhibition of SP-A gene expression. Methods H441 cells, a human lung adenocarcinoma cell line, or human fetal lung explants were incubated with or without insulin. Transcription run-on assays were used to determine SP-A gene transcription rates. Northern blot analysis was used to examine the effect of various signal transduction inhibitors on SP-A gene expression. Immunoblot analysis was used to evaluate the levels and phosphorylation states of signal transduction protein kinases. Results Insulin decreased SP-A gene transcription in human lung epithelial cells within 1 hour. Insulin did not affect p44/42 mitogen-activated protein kinase (MAPK phosphorylation and the insulin inhibition of SP-A mRNA levels was not affected by PD98059, an inhibitor of the p44/42 MAPK pathway. In contrast, insulin increased p70 S6 kinase Thr389 phosphorylation within 15 minutes. Wortmannin or LY294002, both inhibitors of phosphatidylinositol 3-kinase (PI 3-kinase, or rapamycin, an inhibitor of the activation of p70 S6 kinase, a downstream effector in the PI 3-kinase pathway, abolished or attenuated the insulin-induced inhibition of SP-A mRNA levels. Conclusion Insulin inhibition of SP-A gene expression in lung epithelial cells probably occurs via the rapamycin-sensitive PI 3-kinase signaling pathway.

  19. Peroxisome Proliferator-Activated Receptor Alpha Target Genes

    Directory of Open Access Journals (Sweden)

    Maryam Rakhshandehroo

    2010-01-01

    Full Text Available The peroxisome proliferator-activated receptor alpha (PPARα is a ligand-activated transcription factor involved in the regulation of a variety of processes, ranging from inflammation and immunity to nutrient metabolism and energy homeostasis. PPARα serves as a molecular target for hypolipidemic fibrates drugs which bind the receptor with high affinity. Furthermore, PPARα binds and is activated by numerous fatty acids and fatty acid-derived compounds. PPARα governs biological processes by altering the expression of a large number of target genes. Accordingly, the specific role of PPARα is directly related to the biological function of its target genes. Here, we present an overview of the involvement of PPARα in lipid metabolism and other pathways through a detailed analysis of the different known or putative PPARα target genes. The emphasis is on gene regulation by PPARα in liver although many of the results likely apply to other organs and tissues as well.

  20. Association between GRB2/Sos and insulin receptor substrate 1 is not sufficient for activation of extracellular signal-regulated kinases by interleukin-4: implications for Ras activation by insulin.

    Science.gov (United States)

    Pruett, W; Yuan, Y; Rose, E; Batzer, A G; Harada, N; Skolnik, E Y

    1995-03-01

    Insulin receptor substrate 1 (IRS-1) mediates the activation of a variety of signaling pathways by the insulin and insulin-like growth factor 1 receptors by serving as a docking protein for signaling molecules with SH2 domains. We and others have shown that in response to insulin stimulation IRS-1 binds GRB2/Sos and have proposed that this interaction is important in mediating Ras activation by the insulin receptor. Recently, it has been shown that the interleukin (IL)-4 receptor also phosphorylates IRS-1 and an IRS-1-related molecule, 4PS. Unlike insulin, however, IL-4 fails to activate Ras, extracellular signal-regulated kinases (ERKs), or mitogen-activated protein kinases. We have reconstituted the IL-4 receptor into an insulin-responsive L6 myoblast cell line and have shown that IRS-1 is tyrosine phosphorylated to similar degrees in response to insulin and IL-4 stimulation in this cell line. In agreement with previous findings, IL-4 failed to activate the ERKs in this cell line or to stimulate DNA synthesis, whereas the same responses were activated by insulin. Surprisingly, IL-4's failure to activate ERKs was not due to a failure to stimulate the association of tyrosine-phosphorylated IRS-1 with GRB2/Sos; the amounts of GRB2/Sos associated with IRS-1 were similar in insulin- and IL-4-stimulated cells. Moreover, the amounts of phosphatidylinositol 3-kinase activity associated with IRS-1 were similar in insulin- and IL-4-stimulated cells. In contrast to insulin, however, IL-4 failed to induce tyrosine phosphorylation of Shc or association of Shc with GRB2. Thus, ERK activation correlates with Shc tyrosine phosphorylation and formation of an Shc/GRB2 complex. Thus, ERK activation correlates with Shc tyrosine phosphorylation and formation of an Shc/GRB2 complex. Previous studies have indicated that activation of ERks in this cell line is dependent upon Ras since a dominant-negative Ras (Asn-17) blocks ERK activation by insulin. Our findings, taken in the context

  1. The repertoire of bitter taste receptor genes in canids.

    Science.gov (United States)

    Shang, Shuai; Wu, Xiaoyang; Chen, Jun; Zhang, Huanxin; Zhong, Huaming; Wei, Qinguo; Yan, Jiakuo; Li, Haotian; Liu, Guangshuai; Sha, Weilai; Zhang, Honghai

    2017-07-01

    Bitter taste receptors (Tas2rs) play important roles in mammalian defense mechanisms by helping animals detect and avoid toxins in food. Although Tas2r genes have been widely studied in several mammals, minimal research has been performed in canids. To analyze the genetic basis of Tas2r genes in canids, we first identified Tas2r genes in the wolf, maned wolf, red fox, corsac fox, Tibetan fox, fennec fox, dhole and African hunting dog. A total of 183 Tas2r genes, consisting of 118 intact genes, 6 partial genes and 59 pseudogenes, were detected. Differences in the pseudogenes were observed among nine canid species. For example, Tas2r4 was a pseudogene in the dog but might play a functional role in other canid species. The Tas2r42 and Tas2r10 genes were pseudogenes in the maned wolf and dhole, respectively, and the Tas2r5 and Tas2r34 genes were pseudogenes in the African hunting dog; however, these genes were intact genes in other canid species. The differences in Tas2r pseudogenes among canids might suggest that the loss of intact Tas2r genes in canid species is species-dependent. We further compared the 183 Tas2r genes identified in this study with Tas2r genes from ten additional carnivorous species to evaluate the potential influence of diet on the evolution of the Tas2r gene repertoire. Phylogenetic analysis revealed that most of the Tas2r genes from the 18 species intermingled across the tree, suggesting that Tas2r genes are conserved among carnivores. Within canids, we found that some Tas2r genes corresponded to the traditional taxonomic groupings, while some did not. PIC analysis showed that the number of Tas2r genes in carnivores exhibited no positive correlation with diet composition, which might be due to the limited number of carnivores included in our study.

  2. Effects of High Fat Feeding and Diabetes on Regression of Atherosclerosis Induced by Low-Density Lipoprotein Receptor Gene Therapy in LDL Receptor-Deficient Mice.

    Directory of Open Access Journals (Sweden)

    Florian Willecke

    Full Text Available We tested whether a high fat diet (HFD containing the inflammatory dietary fatty acid palmitate or insulin deficient diabetes altered the remodeling of atherosclerotic plaques in LDL receptor knockout (Ldlr-/- mice. Cholesterol reduction was achieved by using a helper-dependent adenovirus (HDAd carrying the gene for the low-density lipoprotein receptor (Ldlr; HDAd-LDLR. After injection of the HDAd-LDLR, mice consuming either HFD, which led to insulin resistance but not hyperglycemia, or low fat diet (LFD, showed regression compared to baseline. However there was no difference between the two groups in terms of atherosclerotic lesion size, or CD68+ cell and lipid content. Because of the lack of effects of these two diets, we then tested whether viral-mediated cholesterol reduction would lead to defective regression in mice with greater hyperglycemia. In both normoglycemic and streptozotocin (STZ-treated hyperglycemic mice, HDAd-LDLR significantly reduced plasma cholesterol levels, decreased atherosclerotic lesion size, reduced macrophage area and lipid content, and increased collagen content of plaque in the aortic sinus. However, reductions in anti-inflammatory and ER stress-related genes were less pronounced in STZ-diabetic mice compared to non-diabetic mice. In conclusion, HDAd-mediated Ldlr gene therapy is an effective and simple method to induce atherosclerosis regression in Ldlr-/- mice in different metabolic states.

  3. Association studies on ghrelin and ghrelin receptor gene polymorphisms with obesity.

    Science.gov (United States)

    Gueorguiev, Maria; Lecoeur, Cécile; Meyre, David; Benzinou, Michael; Mein, Charles A; Hinney, Anke; Vatin, Vincent; Weill, Jacques; Heude, Barbara; Hebebrand, Johannes; Grossman, Ashley B; Korbonits, Márta; Froguel, Philippe

    2009-04-01

    Ghrelin exerts a stimulatory effect on appetite and regulates energy homeostasis. Ghrelin gene variants have been shown to be associated with metabolic traits, although there is evidence suggesting linkage and association with obesity and the ghrelin receptor (GHSR). We hypothesized that these genes are good candidates for susceptibility to obesity. Direct sequencing identified 12 ghrelin single-nucleotide polymorphisms (SNPs) and 8 GHSR SNPs. The 10 common SNPs were genotyped in 1,275 obese subjects and in 1,059 subjects from a general population cohort of European origin. In the obesity case-control study, the GHSR SNP rs572169 was found to be associated with obesity (P = 0.007 in additive model, P = 0.001 in dominant model, odds ratio (OR) 1.73, 95% confidence interval (1.23-2.44)). The ghrelin variant, g.A265T (rs4684677), showed an association with obesity (P = 0.009, BMI adjusted for age and sex) in obese families. The ghrelin variant, g.A-604G (rs27647), showed an association with insulin levels at 2-h post-oral glucose tolerance test (OGTT) (P = 0.009) in obese families. We found an association between the eating behavior "overeating" and the GHSR SNP rs2232169 (P = 0.02) in obese subjects. However, none of these associations remained significant when corrected for multiple comparisons. Replication of the nominal associations with obesity could not be confirmed in a German genome-wide association (GWA) study for rs4684677 and rs572169 polymorphisms. Our data suggest that common polymorphisms in ghrelin and its receptor genes are not major contributors to the development of polygenic obesity, although common variants may alter body weight and eating behavior and contribute to insulin resistance, in particular in the context of early-onset obesity.

  4. Genetic polymorphisms and protein structures in growth hormone, growth hormone receptor, ghrelin, insulin-like growth factor 1 and leptin in Mehraban sheep.

    Science.gov (United States)

    Bahrami, A; Behzadi, Sh; Miraei-Ashtiani, S R; Roh, S-G; Katoh, K

    2013-09-15

    The somatotropic axis, the control system for growth hormone (GH) secretion and its endogenous factors involved in the regulation of metabolism and energy partitioning, has promising potentials for producing economically valuable traits in farm animals. Here we investigated single nucleotide polymorphisms (SNPs) of the genes of factors involved in the somatotropic axis for growth hormone (GH1), growth hormone receptor (GHR), ghrelin (GHRL), insulin-like growth factor 1 (IGF-I) and leptin (LEP), using polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP) and DNA sequencing methods in 452 individual Mehraban sheep. A nonradioactive method to allow SSCP detection was used for genomic DNA and PCR amplification of six fragments: exons 4 and 5 of GH1; exon 10 of GH receptor (GHR); exon 1 of ghrelin (GHRL); exon 1 of insulin-like growth factor-I (IGF-I), and exon 3 of leptin (LEP). Polymorphisms were detected in five of the six PCR products. Two electrophoretic patterns were detected for GH1 exon 4. Five conformational patterns were detected for GH1 exon 5 and LEP exon 3, and three for IGF-I exon 1. Only GHR and GHRL were monomorphic. Changes in protein structures due to variable SNPs were also analyzed. The results suggest that Mehraban sheep, a major breed that is important for the animal industry in Middle East countries, has high genetic variability, opening interesting prospects for future selection programs and preservation strategies. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. Vitamin D receptor and estrogen receptor gene polymorphisms in postmenopausal Danish women

    DEFF Research Database (Denmark)

    Bagger, Y Z; Hassager, C; Heegaard, Anne-Marie

    2000-01-01

    To investigate the polymorphisms of the vitamin D receptor (VDR) and estrogen receptor (ER) genes in relation to biochemical markers of bone turnover (serum osteocalcin and urinary collagen type I degradation products (CrossLaps), and to study ER genotypes in relation to serum lipoproteins, blood...... pressure, or changes in these parameters after 2 years of hormone replacement therapy (HRT) in 499 Danish postmenopausal women....

  6. Gene expression analysis after receptor tyrosine kinase activation reveals new potential melanoma proteins

    International Nuclear Information System (INIS)

    Teutschbein, Janka; Haydn, Johannes M; Samans, Birgit; Krause, Michael; Eilers, Martin; Schartl, Manfred; Meierjohann, Svenja

    2010-01-01

    Melanoma is an aggressive tumor with increasing incidence. To develop accurate prognostic markers and targeted therapies, changes leading to malignant transformation of melanocytes need to be understood. In the Xiphophorus melanoma model system, a mutated version of the EGF receptor Xmrk (Xiphophorus melanoma receptor kinase) triggers melanomagenesis. Cellular events downstream of Xmrk, such as the activation of Akt, Ras, B-Raf or Stat5, were also shown to play a role in human melanomagenesis. This makes the elucidation of Xmrk downstream targets a useful method for identifying processes involved in melanoma formation. Here, we analyzed Xmrk-induced gene expression using a microarray approach. Several highly expressed genes were confirmed by realtime PCR, and pathways responsible for their induction were revealed using small molecule inhibitors. The expression of these genes was also monitored in human melanoma cell lines, and the target gene FOSL1 was knocked down by siRNA. Proliferation and migration of siRNA-treated melanoma cell lines were then investigated. Genes with the strongest upregulation after receptor activation were FOS-like antigen 1 (Fosl1), early growth response 1 (Egr1), osteopontin (Opn), insulin-like growth factor binding protein 3 (Igfbp3), dual-specificity phosphatase 4 (Dusp4), and tumor-associated antigen L6 (Taal6). Interestingly, most genes were blocked in presence of a SRC kinase inhibitor. Importantly, we found that FOSL1, OPN, IGFBP3, DUSP4, and TAAL6 also exhibited increased expression levels in human melanoma cell lines compared to human melanocytes. Knockdown of FOSL1 in human melanoma cell lines reduced their proliferation and migration. Altogether, the data show that the receptor tyrosine kinase Xmrk is a useful tool in the identification of target genes that are commonly expressed in Xmrk-transgenic melanocytes and melanoma cell lines. The identified molecules constitute new possible molecular players in melanoma development

  7. Gene expression analysis after receptor tyrosine kinase activation reveals new potential melanoma proteins

    Directory of Open Access Journals (Sweden)

    Krause Michael

    2010-07-01

    Full Text Available Abstract Background Melanoma is an aggressive tumor with increasing incidence. To develop accurate prognostic markers and targeted therapies, changes leading to malignant transformation of melanocytes need to be understood. In the Xiphophorus melanoma model system, a mutated version of the EGF receptor Xmrk (Xiphophorus melanoma receptor kinase triggers melanomagenesis. Cellular events downstream of Xmrk, such as the activation of Akt, Ras, B-Raf or Stat5, were also shown to play a role in human melanomagenesis. This makes the elucidation of Xmrk downstream targets a useful method for identifying processes involved in melanoma formation. Methods Here, we analyzed Xmrk-induced gene expression using a microarray approach. Several highly expressed genes were confirmed by realtime PCR, and pathways responsible for their induction were revealed using small molecule inhibitors. The expression of these genes was also monitored in human melanoma cell lines, and the target gene FOSL1 was knocked down by siRNA. Proliferation and migration of siRNA-treated melanoma cell lines were then investigated. Results Genes with the strongest upregulation after receptor activation were FOS-like antigen 1 (Fosl1, early growth response 1 (Egr1, osteopontin (Opn, insulin-like growth factor binding protein 3 (Igfbp3, dual-specificity phosphatase 4 (Dusp4, and tumor-associated antigen L6 (Taal6. Interestingly, most genes were blocked in presence of a SRC kinase inhibitor. Importantly, we found that FOSL1, OPN, IGFBP3, DUSP4, and TAAL6 also exhibited increased expression levels in human melanoma cell lines compared to human melanocytes. Knockdown of FOSL1 in human melanoma cell lines reduced their proliferation and migration. Conclusion Altogether, the data show that the receptor tyrosine kinase Xmrk is a useful tool in the identification of target genes that are commonly expressed in Xmrk-transgenic melanocytes and melanoma cell lines. The identified molecules constitute

  8. Hydroxylamine enhances glucose uptake in C2C12 skeletal muscle cells through the activation of insulin receptor substrate 1.

    Science.gov (United States)

    Kimura, Taro; Kato, Eisuke; Machikawa, Tsukasa; Kimura, Shunsuke; Katayama, Shinji; Kawabata, Jun

    2014-02-28

    Diabetes mellitus is a global disease, and the number of patients with it is increasing. Of various agents for treatment, those that directly act on muscle are currently attracting attention because muscle is one of the main tissues in the human body, and its metabolism is decreased in type II diabetes. In this study, we found that hydroxylamine (HA) enhances glucose uptake in C2C12 myotubes. Analysis of HA's mechanism revealed the involvement of IRS1, PI3K and Akt that is related to the insulin signaling pathway. Further investigation about the activation mechanism of insulin receptor or IRS1 by HA may provide a way to develop a novel anti-diabetic agent alternating to insulin. Copyright © 2014 Elsevier Inc. All rights reserved.

  9. Growth hormone, interferon-gamma, and leukemia inhibitory factor promoted tyrosyl phosphorylation of insulin receptor substrate-1

    DEFF Research Database (Denmark)

    Argetsinger, L S; Hsu, G W; Myers, M G

    1995-01-01

    ), the principle substrate of the insulin receptor. Tyrosyl phosphorylation of IRS-1 is a critical step in insulin signaling and provides binding sites for proteins with the appropriate Src homology 2 domains, including the 85-kDa regulatory subunit of phosphatidylinositol (PI) 3'-kinase. In 3T3-F442A fibroblasts......., Campbell, G. S., Allevato, G., Billestrup, N., Norstedt, G., and Carter-Su, C. (1994) J. Biol. Chem. 269, 21709-21717). When other cytokines that activate JAK2 were tested for the ability to stimulate the tyrosyl phosphorylation of IRS-1, stimulation was detected with interferon-gamma and leukemia...... to JAK2. GH is also shown to stimulate binding of IRS-1 to the 85-kDa regulatory subunit of PI 3'-kinase. The ability of GH to stimulate tyrosyl phosphorylation of IRS-1 and its association with PI 3'-kinase provides a biochemical basis for responses shared by insulin and GH including the well...

  10. Allelic association of the D2 dopamine receptor gene with receptor-binding characteristics in alcoholism

    International Nuclear Information System (INIS)

    Noble, E.P.; Blum, K.; Ritchie, T.; Montgomery, A.; Sheridan, P.J.

    1991-01-01

    The allelic association of the human D2 dopamine receptor gene with the binding characteristics of the D2 dopamine receptor was determined in 66 brains of alcoholic and non-alcoholic subjects. In a blinded experiment, DNA from the cerebral cortex was treated with the restriction endonuclease Taql and probed with a 1.5-kilobase (kb) digest of a clone (lambda hD2G1) of the human D2 dopamine receptor gene. The binding characteristics (Kd [binding affinity] and Bmax [number of binding sites]) of the D2 dopamine receptor were determined in the caudate nuclei of these brains using tritiated spiperone as the ligand. The adjusted Kd was significantly lower in alcoholic than in nonalcoholic subjects. In subjects with the A1 allele, in whom a high association with alcoholism was found, the Bmax was significantly reduced compared with the Bmax of subjects with the A2 allele. Moreover, a progressively reduced Bmax was found in subjects with A2/A2, A1/A2, and A1/A1 alleles, with subjects with A2/A2 having the highest mean values, and subjects with A1/A1, the lowest. The polymorphic pattern of the D2 dopamine receptor gene and its differential expression of receptors suggests the involvement of the dopaminergic system in conferring susceptibility to at least one subtype of severe alcoholism

  11. Evidence for natural selection at the melanocortin-3 receptor gene in European and African populations.

    Science.gov (United States)

    Yoshiuchi, Issei

    2016-08-01

    Obesity is increasing steadily in worldwide prevalence and is known to cause serious health problems in association with type 2 diabetes mellitus (T2DM), including hypertension, stroke, and cardiovascular diseases. According to the thrifty gene hypothesis, the natural selection of obesity-related genes is important during feast and famine because they control body weight and fat levels. Past human adaptations to environmental changes in food supply, lifestyle, and geography may have influenced the selection of genes associated with the metabolism of glucose, lipids, and energy. The melanocortin-3 receptor gene (MC3R) is associated with obesity, with MC3R-deficient mice showing increased fat mass. MC3R variations are also linked with childhood obesity and insulin resistance. Here, we aimed to uncover evidence of selection at MC3R. We performed a three-step method to detect selection at MC3R using HapMap population data. We used Wright's F statistics as a measure of population differentiation, the long-range haplotype test to identify extended haplotypes, and the integrated haplotype score (iHS) to detect selection at MC3R. We observed high population differentiation between European and African populations at two MC3R childhood obesity- and insulin resistance-associated single-nucleotide polymorphisms (rs3746619 and rs3827103) using Wright's F statistics. The iHS revealed evidence of natural selection at MC3R. These findings provide evidence for natural selection at MC3R. Further investigation is warranted into adaptive evolution at T2DM- and obesity-associated genes.

  12. Association between vitamin D receptor gene polymorphism (TaqI ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Genetics; Volume 94; Issue 3. Association between vitamin D receptor gene polymorphism (TaqI) and obesity in Chinese population. Hui-Ru Fan Li-Qun Lin Hao Ma Ying Li Chang-Hao Sun. Research Note Volume 94 Issue 3 September 2015 pp 473-478 ...

  13. Genetic diversity of bitter taste receptor gene family in Sichuan

    Indian Academy of Sciences (India)

    Genetic diversity of bitter taste receptor gene family in Sichuan domestic and Tibetan chicken populations. YUAN SU DIYAN LI UMA GAUR YAN WANG NAN WU BINLONG CHEN HONGXIAN XU HUADONG YIN YAODONG HU QING ZHU. RESEARCH ARTICLE Volume 95 Issue 3 September 2016 pp 675-681 ...

  14. Three novel and two known androgen receptor gene mutations ...

    Indian Academy of Sciences (India)

    gene mutations associated with androgen insensitivity syndrome in sex-reversed XY female patients. J. Genet. ... signal and a C-terminal. Keywords. androgen insensitivity syndrome; androgen receptor; truncation mutation; N-terminal domain; XY sex reversal. .... and an increased risk of gonadal tumour. Mutations in SRY.

  15. Association between vitamin D receptor gene polymorphism (TaqI)

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Genetics; Volume 94; Issue 3. Association between vitamin D receptor gene polymorphism (TaqI) and obesity in Chinese population. Hui-Ru Fan Li-Qun Lin Hao Ma Ying Li Chang-Hao Sun. Research Note Volume 94 Issue 3 September 2015 pp 473-478 ...

  16. Genetic diversity of bitter taste receptor gene family in Sichuan ...

    Indian Academy of Sciences (India)

    Previous research had revealed that chicken has only three bitter taste receptor genes (Tas2r1, ... Journal of Genetics, DOI 10.1007/s12041-016-0684-4, Vol. ..... between red-winged blackbirds and European starlings. ... Academic Press,.

  17. Growth factor receptor-binding protein 10 (Grb10) as a partner of phosphatidylinositol 3-kinase in metabolic insulin action.

    Science.gov (United States)

    Deng, Youping; Bhattacharya, Sujoy; Swamy, O Rama; Tandon, Ruchi; Wang, Yong; Janda, Robert; Riedel, Heimo

    2003-10-10

    The regulation of the metabolic insulin response by mouse growth factor receptor-binding protein 10 (Grb10) has been addressed in this report. We find mouse Grb10 to be a critical component of the insulin receptor (IR) signaling complex that provides a functional link between IR and p85 phosphatidylinositol (PI) 3-kinase and regulates PI 3-kinase activity. This regulatory mechanism parallels the established link between IR and p85 via insulin receptor substrate (IRS) proteins. A direct association was demonstrated between Grb10 and p85 but was not observed between Grb10 and IRS proteins. In addition, no effect of mouse Grb10 was observed on the association between IRS-1 and p85, on IRS-1-associated PI 3-kinase activity, or on insulin-mediated activation of IR or IRS proteins. A critical role of mouse Grb10 was observed in the regulation of PI 3-kinase activity and the resulting metabolic insulin response. Dominant-negative Grb10 domains, in particular the SH2 domain, eliminated the metabolic response to insulin in differentiated 3T3-L1 adipocytes. This was consistently observed for glycogen synthesis, glucose and amino acid transport, and lipogenesis. In parallel, the same metabolic responses were substantially elevated by increased levels of Grb10. A similar role of Grb10 was confirmed in mouse L6 cells. In addition to the SH2 domain, the Pro-rich amino-terminal region of Grb10 was implicated in the regulation of PI 3-kinase catalytic activity. These regulatory roles of Grb10 were extended to specific insulin mediators downstream of PI 3-kinase including PKB/Akt, glycogen synthase kinase, and glycogen synthase. In contrast, a regulatory role of Grb10 in parallel insulin response pathways including p70 S6 kinase, ubiquitin ligase Cbl, or mitogen-activated protein kinase p38 was not observed. The dissection of the interaction of mouse Grb10 with p85 and the resulting regulation of PI 3-kinase activity should help elucidate the complexity of the IR signaling

  18. Liver lipid molecules induce PEPCK-C gene transcription and attenuate insulin action

    International Nuclear Information System (INIS)

    Chen Guoxun

    2007-01-01

    Cytosolic phosphoenolpyruvate carboxykinase (PEPCK-C) plays key roles in gluconeogenesis, glyceroneogenesis, and cataplerosis. Experiments were designed to examine the effects of endogenous lipid molecules from rat livers on the expression of PEPCK-C gene in primary rat hepatocytes. The lipid extracts prepared from livers of Zucker fatty, lean, and Wistar rats induced the expression levels of PEPCK-C transcripts. Insulin-mediated reduction of PEPCK-C gene expression was attenuated by the same treatment. The lipid extracts induced the relative luciferase activity of reporter gene constructs that contain a 2.2-kb 5' promoter fragment of PEPCK-C gene, but not the construct that contains only the 3' untranslated region (UTR) of its mRNA. The estimated half life of PEPCK-C transcripts in the presence of the lipid extract is the same as that in the absence of it. My results demonstrate for the first time that endogenous lipid molecules induce PEPCK-C gene transcription and attenuate insulin action in liver

  19. The CAPN10 Gene Is Associated with Insulin Resistance Phenotypes in the Spanish Population

    Science.gov (United States)

    Sáez, María E.; González-Sánchez, José L.; Ramírez-Lorca, Reposo; Martínez-Larrad, María T.; Zabena, Carina; González, Alejandro; Morón, Francisco J.; Ruiz, Agustín; Serrano-Ríos, Manuel

    2008-01-01

    Cardiovascular disease is the leading cause of morbidity and mortality in the industrialized world. Familial aggregation of cardiovascular risk factors is a frequent finding, but genetic factors affecting its presentation are still poorly understood. The calpain 10 gene (CAPN10) has been associated with type 2 diabetes (T2DM), a complex metabolic disorder with increased risk of cardiovascular disease. Moreover, the CAPN10 gene has been associated with the presence of metabolic syndrome (MS) in T2DM and in polycystic ovary syndrome (PCOS). In this work, we have analysed whether the polymorphisms UCSNP44, -43, -19 and -63 are related to several cardiovascular risk factors in the context of MS. Molecular analysis of CAPN10 gene was performed in 899 individuals randomly chosen from a cross-sectional population-based epidemiological survey. We have found that CAPN10 gene in our population is mainly associated with two indicators of the presence of insulin resistance: glucose levels two hours after a 75-g oral glucose tolerance test (OGTT) and HOMA values, although cholesterol levels and blood pressure values are also influenced by CAPN10 variants. In addition, the 1221/1121 haplogenotype is under-represented in individuals that fulfil the International Diabetes Federation (IDF) diagnostic criteria for MS. Our results suggest that CAPN10 gene is associated with insulin resistance phenotypes in the Spanish population. PMID:18698425

  20. The CAPN10 gene is associated with insulin resistance phenotypes in the Spanish population.

    Directory of Open Access Journals (Sweden)

    María E Sáez

    Full Text Available Cardiovascular disease is the leading cause of morbidity and mortality in the industrialized world. Familial aggregation of cardiovascular risk factors is a frequent finding, but genetic factors affecting its presentation are still poorly understood. The calpain 10 gene (CAPN10 has been associated with type 2 diabetes (T2DM, a complex metabolic disorder with increased risk of cardiovascular disease. Moreover, the CAPN10 gene has been associated with the presence of metabolic syndrome (MS in T2DM and in polycystic ovary syndrome (PCOS. In this work, we have analysed whether the polymorphisms UCSNP44, -43, -19 and -63 are related to several cardiovascular risk factors in the context of MS. Molecular analysis of CAPN10 gene was performed in 899 individuals randomly chosen from a cross-sectional population-based epidemiological survey. We have found that CAPN10 gene in our population is mainly associated with two indicators of the presence of insulin resistance: glucose levels two hours after a 75-g oral glucose tolerance test (OGTT and HOMA values, although cholesterol levels and blood pressure values are also influenced by CAPN10 variants. In addition, the 1221/1121 haplogenotype is under-represented in individuals that fulfil the International Diabetes Federation (IDF diagnostic criteria for MS. Our results suggest that CAPN10 gene is associated with insulin resistance phenotypes in the Spanish population.

  1. [Plasma IL-18 levels are related to insulin and are modulated by IL-18 gene polymorphisms].

    Science.gov (United States)

    Martinez-Hervas, Sergio; Martínez-Barquero, Vanesa; Nuñez Savall, Ester; Lendínez, Verónica; Olivares, Laura; Benito, Esther; Real, Jose T; Chaves, F Javier; Ascaso, Juan F

    2015-01-01

    Atherosclerosis is an inflammatory chronic disease influenced by multiple factors. Different prospective studies have shown that plasmatic levels of inflammatory markers were related to atherosclerosis and cardiovascular disease. To evaluate whether plasmatic levels of interleukin 18 (IL-18) are modulated by SNPs (single nucleotide polymorphisms) of the IL 18 gene and its possible association with insulin levels and other cardiovascular risk factors. 746 individuals were studied for a period of two years by opportunistic selection in the metropolitan area of Valencia. Parameters of lipid and glucose metabolism were analyzed by standard methodology. IL-18 was measured by ELISA. Individuals with insulin resistance showed significant higher levels of IL-18. IL 18 was significantly correlated with insulin levels and other cardiovascular risk factors. The CC genotype of the rs1834481 SNP was significantly associated with lower levels of IL-18. However, the GG genotype of the rs7559479 was associated with significant higher levels of IL-18. IL-18 is associated with insulin resistance and other cardiovascular risk factors, being those levels genetically regulated. Copyright © 2015 Sociedad Española de Arteriosclerosis. Published by Elsevier España. All rights reserved.

  2. IL-4 and IL-13 Receptor Signaling From 4PS to Insulin Receptor Substrate 2: There and Back Again, a Historical View.

    Science.gov (United States)

    Keegan, Achsah D; Zamorano, Jose; Keselman, Aleksander; Heller, Nicola M

    2018-01-01

    In this historical perspective, written in honor of Dr. William E. Paul, we describe the initial discovery of one of the dominant substrates for tyrosine phosphorylation stimulated by IL-4. We further describe how this "IL-4-induced phosphorylated substrate" (4PS) was characterized as a member of the insulin receptor substrate (IRS) family of large adaptor proteins that link IL-4 and insulin receptors to activation of the phosphatidyl-inositol 3' kinase pathway as well as other downstream signaling pathways. The relative contribution of the 4PS/IRS pathway to the early models of IL-4-induced proliferation and suppression of apoptosis are compared to our more recent understanding of the complex interplay between positive and negative regulatory pathways emanating from members of the IRS family that impact allergic responses.

  3. IL-4 and IL-13 Receptor Signaling From 4PS to Insulin Receptor Substrate 2: There and Back Again, a Historical View

    Directory of Open Access Journals (Sweden)

    Achsah D. Keegan

    2018-05-01

    Full Text Available In this historical perspective, written in honor of Dr. William E. Paul, we describe the initial discovery of one of the dominant substrates for tyrosine phosphorylation stimulated by IL-4. We further describe how this “IL-4-induced phosphorylated substrate” (4PS was characterized as a member of the insulin receptor substrate (IRS family of large adaptor proteins that link IL-4 and insulin receptors to activation of the phosphatidyl-inositol 3′ kinase pathway as well as other downstream signaling pathways. The relative contribution of the 4PS/IRS pathway to the early models of IL-4-induced proliferation and suppression of apoptosis are compared to our more recent understanding of the complex interplay between positive and negative regulatory pathways emanating from members of the IRS family that impact allergic responses.

  4. Recruitment of GABA(A) receptors and fearfulness in chicks: modulation by systemic insulin and/or epinephrine.

    Science.gov (United States)

    Cid, Mariana Paula; Toledo, Carolina Maribel; Salvatierra, Nancy Alicia

    2013-02-01

    One-day-old chicks were individually assessed on their latency to peck pebbles, and categorized as low latency (LL) or high latency (HL) according to fear. Interactions between acute stress and systemic insulin and epinephrine on GABA(A) receptor density in the forebrain were studied. At 10 days of life, LL and HL chicks were intraperitoneally injected with insulin, epinephrine or saline, and immediately after stressed by partial water immersion for 15 min and killed by decapitation. Forebrains were dissected and the GABA(A) receptor density was measured ex vivo by the (3)[H]-flunitrazepam binding assay in synaptosomes. In non-stressed chicks, insulin (non-hypoglycemic dose) at 2.50 IU/kg of body weight incremented the Bmax by 40.53% in the HL chicks compared to saline group whereas no significant differences were observed between individuals in the LL subpopulation. Additionally, insulin increased the Bmax (23.48%) in the HL group with respect to the LL ones, indicating that the insulin responses were different according to the anxiety of each category. Epinephrine administration (0.25 and 0.50mg/kg) incremented the Bmax in non-stressed chicks, in the LL group by about 37% and 33%, respectively, compared to ones injected with saline. In the stressed chicks, 0.25mg/kg bw epinephrine increased the Bmax significantly in the HL group by about 24% compared to saline, suggesting that the effect of epinephrine was only observed in the HL group under acute stress conditions. Similarly, the same epinephrine doses co-administered with insulin increased the receptor density in both subpopulations and also showed that the highest dose of epinephrine did not further increase the maximum density of GABA(A)R in HL chicks. These results suggest that systemic epinephrine, perhaps by evoking central norepinephrine release, modulated the increase in the forebrain GABA(A) receptor recruitment induced by both insulin and stress in different ways depending on the subpopulation

  5. Self-renewal of human embryonic stem cells requires insulin-like growth factor-1 receptor and ERBB2 receptor signaling

    Science.gov (United States)

    Wang, Linlin; Schulz, Thomas C.; Sherrer, Eric S.; Dauphin, Derek S.; Shin, Soojung; Nelson, Angelique M.; Ware, Carol B.; Zhan, Mei; Song, Chao-Zhong; Chen, Xiaoji; Brimble, Sandii N.; McLean, Amanda; Galeano, Maria J.; Uhl, Elizabeth W.; D'Amour, Kevin A.; Chesnut, Jonathan D.; Rao, Mahendra S.

    2007-01-01

    Despite progress in developing defined conditions for human embryonic stem cell (hESC) cultures, little is known about the cell-surface receptors that are activated under conditions supportive of hESC self-renewal. A simultaneous interrogation of 42 receptor tyrosine kinases (RTKs) in hESCs following stimulation with mouse embryonic fibroblast (MEF) conditioned medium (CM) revealed rapid and prominent tyrosine phosphorylation of insulin receptor (IR) and insulin-like growth factor-1 receptor (IGF1R); less prominent tyrosine phosphorylation of epidermal growth factor receptor (EGFR) family members, including ERBB2 and ERBB3; and trace phosphorylation of fibroblast growth factor receptors. Intense IGF1R and IR phosphorylation occurred in the absence of MEF conditioning (NCM) and was attributable to high concentrations of insulin in the proprietary KnockOut Serum Replacer (KSR). Inhibition of IGF1R using a blocking antibody or lentivirus-delivered shRNA reduced hESC self-renewal and promoted differentiation, while disruption of ERBB2 signaling with the selective inhibitor AG825 severely inhibited hESC proliferation and promoted apoptosis. A simple defined medium containing an IGF1 analog, heregulin-1β (a ligand for ERBB2/ERBB3), fibroblast growth factor-2 (FGF2), and activin A supported long-term growth of multiple hESC lines. These studies identify previously unappreciated RTKs that support hESC proliferation and self-renewal, and provide a rationally designed medium for the growth and maintenance of pluripotent hESCs. PMID:17761519

  6. Independent signaling by Drosophila insulin receptor for axon guidance and growth.

    Science.gov (United States)

    Li, Caroline R; Guo, Dongyu; Pick, Leslie

    2013-01-01

    The Drosophila insulin receptor (DInR) regulates a diverse array of biological processes including growth, axon guidance, and sugar homeostasis. Growth regulation by DInR is mediated by Chico, the Drosophila homolog of vertebrate insulin receptor substrate proteins IRS1-4. In contrast, DInR regulation of photoreceptor axon guidance in the developing visual system is mediated by the SH2-SH3 domain adaptor protein Dreadlocks (Dock). In vitro studies by others identified five NPXY motifs, one in the juxtamembrane region and four in the signaling C-terminal tail (C-tail), important for interaction with Chico. Here we used yeast two-hybrid assays to identify regions in the DInR C-tail that interact with Dock. These Dock binding sites were in separate portions of the C-tail from the previously identified Chico binding sites. To test whether these sites are required for growth or axon guidance in whole animals, a panel of DInR proteins, in which the putative Chico and Dock interaction sites had been mutated individually or in combination, were tested for their ability to rescue viability, growth and axon guidance defects of dinr mutant flies. Sites required for viability were identified. Unexpectedly, mutation of both putative Dock binding sites, either individually or in combination, did not lead to defects in photoreceptor axon guidance. Thus, either sites also required for viability are necessary for DInR function in axon guidance and/or there is redundancy built into the DInR/Dock interaction such that Dock is able to interact with multiple regions of DInR. We also found that simultaneous mutation of all five NPXY motifs implicated in Chico interaction drastically decreased growth in both male and female adult flies. These animals resembled chico mutants, supporting the notion that DInR interacts directly with Chico in vivo to control body size. Mutation of these five NPXY motifs did not affect photoreceptor axon guidance, segregating the roles of DInR in the

  7. Insulin-increased L-arginine transport requires A(2A adenosine receptors activation in human umbilical vein endothelium.

    Directory of Open Access Journals (Sweden)

    Enrique Guzmán-Gutiérrez

    Full Text Available Adenosine causes vasodilation of human placenta vasculature by increasing the transport of arginine via cationic amino acid transporters 1 (hCAT-1. This process involves the activation of A(2A adenosine receptors (A(2AAR in human umbilical vein endothelial cells (HUVECs. Insulin increases hCAT-1 activity and expression in HUVECs, and A(2AAR stimulation increases insulin sensitivity in subjects with insulin resistance. However, whether A(2AAR plays a role in insulin-mediated increase in L-arginine transport in HUVECs is unknown. To determine this, we first assayed the kinetics of saturable L-arginine transport (1 minute, 37°C in the absence or presence of nitrobenzylthioinosine (NBTI, 10 µmol/L, adenosine transport inhibitor and/or adenosine receptors agonist/antagonists. We also determined hCAT-1 protein and mRNA expression levels (Western blots and quantitative PCR, and SLC7A1 (for hCAT-1 reporter promoter activity. Insulin and NBTI increased the extracellular adenosine concentration, the maximal velocity for L-arginine transport without altering the apparent K(m for L-arginine transport, hCAT-1 protein and mRNA expression levels, and SLC7A1 transcriptional activity. An A2AAR antagonist ZM-241385 blocked these effects. ZM241385 inhibited SLC7A1 reporter transcriptional activity to the same extent in cells transfected with pGL3-hCAT-1(-1606 or pGL3-hCAT-1(-650 constructs in the presence of NBTI + insulin. However, SLC7A1 reporter activity was increased by NBTI only in cells transfected with pGL3-hCAT-1(-1606, and the ZM-241385 sensitive fraction of the NBTI response was similar in the absence or in the presence of insulin. Thus, insulin modulation of hCAT-1 expression and activity requires functional A(2AAR in HUVECs, a mechanism that may be applicable to diseases associated with fetal insulin resistance, such as gestational diabetes.

  8. Stimulation of albumin gene transcription by insulin in primary cultures of rat hepatocytes

    International Nuclear Information System (INIS)

    Lloyd, C.E.; Kalinyak, J.E.; Hutson, S.M.; Jefferson, L.S.

    1987-01-01

    The first goal of the work reported here was to prepare single-stranded DNA sequences for use in studies on the regulation of albumin gene expression. A double-stranded rat albumin cDNA clone was subcloned into the bacteriophage vector M13mp7. Single-stranded recombinant clones were screened for albumin sequences containing either the mRNA strand or the complementary strand. Two clones were selected that contained the 1200 nucleotide long 3' end of the albumin sequence. DNA from the clone containing the mRNA strand was used as a template for DNA polymerase I to prepare a radiolabeled, single-stranded cDNA to albumin mRNA. This radiolabeled cDNA probe was used to quantitate the relative abundance of albumin mRNA in samples of total cellular RNA. DNA from the clone containing the complementary strand was used to measure relative rates of albumin gene transcription in isolated nuclei. The second goal was to use the single-stranded DNA probes to investigate the mechanism of the insulin-mediated stimulation of albumin synthesis in primary cultures of rat hepatocytes. Addition of insulin to hepatocytes maintained in a chemically defined, serum-free medium for 40 h in the absence of any hormones resulted in a specific 1.5- to 2.5-fold stimulation of albumin gene transcription that was maximal at 3 h and was maintained above control values for at least 24 h. The rate of albumin gene transcription in nuclei isolated from livers of diabetic rats was reduced to 50% of the value recorded in control nuclei. Taken together, these findings demonstrate that insulin regulates synthesis of albumin at the level of gene transcription

  9. Longitudinal profiling of the tissue-specific expression of genes related with insulin sensitivity in dairy cows during lactation focusing on different fat depots.

    Directory of Open Access Journals (Sweden)

    Behnam Saremi

    Full Text Available In dairy cows the milk associated energy output in early lactation exceeds the input via voluntary feed intake. To spare glucose for mammary lactose synthesis, peripheral insulin sensitivity (IS is reduced and fat mobilization is stimulated. For these processes a link between IS and the endocrine functions of adipose tissue (AT is likely; we thus aimed to characterise the mRNA expression from bovine AT derived proteins and receptors that are related to IS according to the literature in metabolically active tissues plus systemic IS throughout lactation. Conjugated linoleic acids (CLA reduce milk fat thus decreasing the milk drain of energy and potentially dampening lipolysis, but may also affect IS. Subcutaneous (s.c. AT and liver from pluriparous cows receiving either control fat or CLA supplement (100 g/day from 1 to 182 days in milk each were biopsied covering week -3 to 36 relative to parturition. In an additional trial with primiparous cows treated analogously and slaughtered on days in milk 1, 42 or 105, samples from liver, udder, skeletal muscle and 3 visceral and 3 s.c. AT were obtained and assayed for mRNA abundance of adiponectin, its receptors, leptin, leptin receptor, PPARγ, PPARγ2, IL-6, and TNF-α. In pluriparous animals, the mRNA abundance of most of the target genes decreased after parturition in s.c. AT but increased in liver. In primiparous cows, AT depot specific differences were mostly related to retroperitoneal AT; adiponectin receptor 1 and TNF-α were affected predominantly. CLA effects in primiparous cows were largely limited to decreased PPARγ2 mRNA abundance in udder tissue. In pluriparous cows, insulin secretion was increased by CLA resulting in decreased systemic IS but without consistent changes in tissue target mRNA abundance. The temporal gene expression profiles from the adipokines and related receptors support their coactive function in adapting to the needs of lactation.

  10. Longitudinal Profiling of the Tissue-Specific Expression of Genes Related with Insulin Sensitivity in Dairy Cows during Lactation Focusing on Different Fat Depots

    Science.gov (United States)

    Saremi, Behnam; Winand, Sarah; Friedrichs, Paula; Kinoshita, Asako; Rehage, Jürgen; Dänicke, Sven; Häussler, Susanne; Breves, Gerhard; Mielenz, Manfred; Sauerwein, Helga

    2014-01-01

    In dairy cows the milk associated energy output in early lactation exceeds the input via voluntary feed intake. To spare glucose for mammary lactose synthesis, peripheral insulin sensitivity (IS) is reduced and fat mobilization is stimulated. For these processes a link between IS and the endocrine functions of adipose tissue (AT) is likely; we thus aimed to characterise the mRNA expression from bovine AT derived proteins and receptors that are related to IS according to the literature in metabolically active tissues plus systemic IS throughout lactation. Conjugated linoleic acids (CLA) reduce milk fat thus decreasing the milk drain of energy and potentially dampening lipolysis, but may also affect IS. Subcutaneous (s.c.) AT and liver from pluriparous cows receiving either control fat or CLA supplement (100 g/day from 1 to 182 days in milk each) were biopsied covering week −3 to 36 relative to parturition. In an additional trial with primiparous cows treated analogously and slaughtered on days in milk 1, 42 or 105, samples from liver, udder, skeletal muscle and 3 visceral and 3 s.c. AT were obtained and assayed for mRNA abundance of adiponectin, its receptors, leptin, leptin receptor, PPARγ, PPARγ2, IL-6, and TNF-α. In pluriparous animals, the mRNA abundance of most of the target genes decreased after parturition in s.c. AT but increased in liver. In primiparous cows, AT depot specific differences were mostly related to retroperitoneal AT; adiponectin receptor 1 and TNF-α were affected predominantly. CLA effects in primiparous cows were largely limited to decreased PPARγ2 mRNA abundance in udder tissue. In pluriparous cows, insulin secretion was increased by CLA resulting in decreased systemic IS but without consistent changes in tissue target mRNA abundance. The temporal gene expression profiles from the adipokines and related receptors support their coactive function in adapting to the needs of lactation. PMID:24465964

  11. Probing Receptor Specificity by Sampling the Conformational Space of the Insulin-like Growth Factor II C-domain

    Czech Academy of Sciences Publication Activity Database

    Hexnerová, Rozálie; Křížková, Květoslava; Fábry, Milan; Sieglová, Irena; Kedrová, Kateřina; Collinsová, Michaela; Ullrichová, P.; Srb, Pavel; Williams, C.; Crump, M. P.; Tošner, Z.; Jiráček, Jiří; Veverka, Václav; Žáková, Lenka

    2016-01-01

    Roč. 291, č. 40 (2016), s. 21234-21245 ISSN 0021-9258 R&D Projects: GA ČR GA15-19018S; GA MŠk(CZ) LK11205; GA MŠk(CZ) LO1304 Institutional support: RVO:61388963 ; RVO:68378050 Keywords : insulin * IGF-2 * receptor Subject RIV: CE - Biochemistry Impact factor: 4.125, year: 2016 http://www.jbc.org/content/291/40/21234.full

  12. Gene specific actions of thyroid hormone receptor subtypes.

    Directory of Open Access Journals (Sweden)

    Jean Z Lin

    Full Text Available There are two homologous thyroid hormone (TH receptors (TRs α and β, which are members of the nuclear hormone receptor (NR family. While TRs regulate different processes in vivo and other highly related NRs regulate distinct gene sets, initial studies of TR action revealed near complete overlaps in their actions at the level of individual genes. Here, we assessed the extent that TRα and TRβ differ in target gene regulation by comparing effects of equal levels of stably expressed exogenous TRs +/- T(3 in two cell backgrounds (HepG2 and HeLa. We find that hundreds of genes respond to T(3 or to unliganded TRs in both cell types, but were not able to detect verifiable examples of completely TR subtype-specific gene regulation. TR actions are, however, far from identical and we detect TR subtype-specific effects on global T(3 response kinetics in HepG2 cells and many examples of TR subtype specificity at the level of individual genes, including effects on magnitude of response to TR +/- T(3, TR regulation patterns and T(3 dose response. Cycloheximide (CHX treatment confirms that at least some differential effects involve verifiable direct TR target genes. TR subtype/gene-specific effects emerge in the context of widespread variation in target gene response and we suggest that gene-selective effects on mechanism of TR action highlight differences in TR subtype function that emerge in the environment of specific genes. We propose that differential TR actions could influence physiologic and pharmacologic responses to THs and selective TR modulators (STRMs.

  13. Targeting Insulin-Like Growth Factor 1 Receptor Inhibits Pancreatic Cancer Growth and Metastasis

    Science.gov (United States)

    Subramani, Ramadevi; Lopez-Valdez, Rebecca; Arumugam, Arunkumar; Nandy, Sushmita; Boopalan, Thiyagarajan; Lakshmanaswamy, Rajkumar

    2014-01-01

    Pancreatic cancer is one of the most lethal cancers. Increasing incidence and mortality indicates that there is still much lacking in detection and management of the disease. This is partly due to a lack of specific symptoms during early stages of the disease. Several growth factor receptors have been associated with pancreatic cancer. Here, we have investigated if an RNA interference approach targeted to IGF-IR could be effective and efficient against pancreatic cancer growth and metastasis. For that, we evaluated the effects of IGF-1R inhibition using small interfering RNA (siRNAs) on tumor growth and metastasis in HPAC and PANC-1 pancreatic cancer cell lines. We found that silencing IGF-1R inhibits pancreatic cancer growth and metastasis by blocking key signaling pathways such AKT/PI3K, MAPK, JAK/STAT and EMT. Silencing IGF-1R resulted in an anti-proliferative effect in PANC-1 and HPAC pancreatic cancer cell lines. Matrigel invasion, transwell migration and wound healing assays also revealed a role for IGF-1R in metastatic properties of pancreatic cancer. These results were further confirmed using Western blotting analysis of key intermediates involved in proliferation, epithelial mesenchymal transition, migration, and invasion. In addition, soft agar assays showed that silencing IGF-1R also blocks the colony forming capabilities of pancreatic cancer cells in vitro. Western blots, as well as, flow cytometric analysis revealed the induction of apoptosis in IGF-1R silenced cells. Interestingly, silencing IGF-1R also suppressed the expression of insulin receptor β. All these effects together significantly control pancreatic cancer cell growth and metastasis. To conclude, our results demonstrate the significance of IGF-1R in pancreatic cancer. PMID:24809702

  14. Insulin like growth factor 2 regulation of aryl hydrocarbon receptor in MCF-7 breast cancer cells

    International Nuclear Information System (INIS)

    Tomblin, Justin K.; Salisbury, Travis B.

    2014-01-01

    Highlights: •IGF-2 stimulates concurrent increases in AHR and CCND1 expression. •IGF-2 promotes the binding of AHR to the endogenous cyclin D1 promoter. •AHR knockdown inhibits IGF-2 stimulated increases in CCND1 mRNA and protein. •AHR knockdown inhibits IGF-2 stimulated increases in MCF-7 proliferation. -- Abstract: Insulin like growth factor (IGF)-1 and IGF-2 stimulate normal growth, development and breast cancer cell proliferation. Cyclin D1 (CCND1) promotes cell cycle by inhibiting retinoblastoma protein (RB1). The aryl hydrocarbon receptor (AHR) is a major xenobiotic receptor that also regulates cell cycle. The purpose of this study was to investigate whether IGF-2 promotes MCF-7 breast cancer proliferation by inducing AHR. Western blot and quantitative real time PCR (Q-PCR) analysis revealed that IGF-2 induced an approximately 2-fold increase (P < .001) in the expression of AHR and CCND1. Chromatin immunoprecipitation (ChIP), followed by Q-PCR indicated that IGF-2 promoted (P < .001) a 7-fold increase in AHR binding on the CCND1 promoter. AHR knockdown significantly (P < .001) inhibited IGF-2 stimulated increases in CCND1 mRNA and protein. AHR knockdown cells were less (P < .001) responsive to the proliferative effects of IGF-2 than control cells. Collectively, our findings have revealed a new regulatory mechanism by which IGF-2 induction of AHR promotes the expression of CCND1 and the proliferation of MCF-7 cells. This previously uncharacterized pathway could be important for the proliferation of IGF responsive cancer cells that also express AHR

  15. Insulin like growth factor 2 regulation of aryl hydrocarbon receptor in MCF-7 breast cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Tomblin, Justin K.; Salisbury, Travis B., E-mail: salisburyt@marshall.edu

    2014-01-17

    Highlights: •IGF-2 stimulates concurrent increases in AHR and CCND1 expression. •IGF-2 promotes the binding of AHR to the endogenous cyclin D1 promoter. •AHR knockdown inhibits IGF-2 stimulated increases in CCND1 mRNA and protein. •AHR knockdown inhibits IGF-2 stimulated increases in MCF-7 proliferation. -- Abstract: Insulin like growth factor (IGF)-1 and IGF-2 stimulate normal growth, development and breast cancer cell proliferation. Cyclin D1 (CCND1) promotes cell cycle by inhibiting retinoblastoma protein (RB1). The aryl hydrocarbon receptor (AHR) is a major xenobiotic receptor that also regulates cell cycle. The purpose of this study was to investigate whether IGF-2 promotes MCF-7 breast cancer proliferation by inducing AHR. Western blot and quantitative real time PCR (Q-PCR) analysis revealed that IGF-2 induced an approximately 2-fold increase (P < .001) in the expression of AHR and CCND1. Chromatin immunoprecipitation (ChIP), followed by Q-PCR indicated that IGF-2 promoted (P < .001) a 7-fold increase in AHR binding on the CCND1 promoter. AHR knockdown significantly (P < .001) inhibited IGF-2 stimulated increases in CCND1 mRNA and protein. AHR knockdown cells were less (P < .001) responsive to the proliferative effects of IGF-2 than control cells. Collectively, our findings have revealed a new regulatory mechanism by which IGF-2 induction of AHR promotes the expression of CCND1 and the proliferation of MCF-7 cells. This previously uncharacterized pathway could be important for the proliferation of IGF responsive cancer cells that also express AHR.

  16. The phosphatidylinositol-3 kinase pathway is not essential for insulin-like growth factor I receptor-mediated clonogenic radioresistance

    International Nuclear Information System (INIS)

    Yu, Dong; Watanabe, Hiroshi; Shibuya, Hitoshi; Miura, Masahiko

    2002-01-01

    The insulin-like growth factor I receptor (IGF-IR) is known to induce clonogenic radioresistance in cells following ionizing irradiation. To explore the downstream signaling pathways, we focused on the phosphatidylinositol-3 kinase (PI3-K) pathway, which is thought to be the primary cell survival signal originating from the receptor. For this purpose, R- cells deficient in the endogenous IGF-IR were used as a recipient of the human IGF-IR with or without mutations at potential PI3-K activation sites: NPXY 950 and Y 1316 XXM. Mutats with double mutation at Y950/Y1316 exhibited not abrogated, but reduced activation of insulin receptor substance-1 (IRS-1), PI3-K, and Akt upon IGF-I stimulation. However, the mutants had the same clonogenic radioresistance as cells with wild type (WT) receptors. Neither wortmannin nor LY294002, specific inhibitors of PI3-K, affected the radioresistance of cells with WT receptors at concentrations specific for PI3-K. Collectively, these results indicate that the PI3-K pathway is not essential for IGF-IR-mediated clonogenic radioresistance. (author)

  17. Insulin-like growth factor-I and insulin-like growth factor binding proteins in the bovine mammary gland: Receptors, endogenous secretion, and appearance in milk

    International Nuclear Information System (INIS)

    Campbell, P.G.

    1988-01-01

    This is the first study to characterize both insulin-like growth factor-I (IGF-I) and insulin-like growth factor binding proteins (IGFBPs) in bovine milk, to characterize the IGF-I receptor in the dry and lactating mammary gland, and to report de novo synthesis and secretion of IGF-I and IGFBP from normal mammary tissue. Immunoreactive IGF-I was principally associated with 45 kDa IGFBP in milk. Multiparous cows had a higher IGF-I concentration of 307 ng/ml than primiparous cows at 147 ng/ml. IGF-I concentration on day 56 of lactation was 34 ng/ml for combined parity groups. At parturition, IGF-I mass in blood and milk pools was 1.4 and 1.2 mg, respectively. Binding of 125 I-IGF-I was specific for IGF-I with anIC 50 of 2.2 ng which was a 10- and 1273-fold greater affinity than IGF-II and insulin, respectively. Association constants, as determined by Scatchard analysis, were similar for both pregnant and lactating cows at 3.5 and 4.0 L/nM, respectively. In addition, estimated mean receptor concentration was 0.25 and 0.23 pM/mg protein for pregnant and lactating cows, respectively. In a survey of mammary microscomes prepared from 48 cows, 125 I-IGF-I binding declined with progressing lactation and a similar trend was observed during pregnancy

  18. Synthesis and Evaluation of a Library of Trifunctional Scaffold-Derived Compounds as Modulators of the Insulin Receptor.

    Science.gov (United States)

    Fabre, Benjamin; Pícha, Jan; Vaněk, Václav; Selicharová, Irena; Chrudinová, Martina; Collinsová, Michaela; Žáková, Lenka; Buděšínský, Miloš; Jiráček, Jiří

    2016-12-12

    We designed a combinatorial library of trifunctional scaffold-derived compounds, which were derivatized with 30 different in-house-made azides. The compounds were proposed to mimic insulin receptor (IR)-binding epitopes in the insulin molecule and bind to and activate this receptor. This work has enabled us to test our synthetic and biological methodology and to prove its robustness and reliability for the solid-phase synthesis and testing of combinatorial libraries of the trifunctional scaffold-derived compounds. Our effort resulted in the discovery of two compounds, which were able to weakly induce the autophosphorylation of IR and weakly bind to this receptor at a 0.1 mM concentration. Despite these modest biological results, which well document the well-known difficulty in modulating protein-protein interactions, this study represents a unique example of targeting the IR with a set of nonpeptide compounds that were specifically designed and synthesized for this purpose. We believe that this work can open new perspectives for the development of next-generation insulin mimetics based on the scaffold structure.

  19. Overexpression of Insulin-like Growth Factor-1 Receptor Is Associated With Penile Cancer Progression.

    Science.gov (United States)

    Ball, Mark W; Bezerra, Stephania M; Chaux, Alcides; Faraj, Sheila F; Gonzalez-Roibon, Nilda; Munari, Enrico; Sharma, Rajni; Bivalacqua, Trinity J; Netto, George J; Burnett, Arthur L

    2016-06-01

    To evaluate insulin-like growth factor-1 receptor (IGF1R) expression in penile cancer and its association with oncologic outcomes. Tissue microarrays were constructed from 53 patients treated at our institution. Expression of IGF1R was evaluated using a Her2-like scoring system. Overexpression was defined as 1+ or greater membranous staining. Association of IGF1R expression with pathologic features was assessed with comparative statistics, and association with local recurrence, progression to nodal or distance metastases, or death was assessed with Kaplan-Meier survival analysis and Cox proportional hazard regression models. Overall, IGF1R overexpression was seen in 33 (62%) cases. With a median follow-up of 27.8 months, IGF1R overexpression was associated with inferior progression-free survival (PFS) (P  =  .003). In a multivariable model controlling for grade, T stage, perineural invasion, and lymphovascular invasion, IGF1R expression was independently associated with disease progression (hazard ratio 2.3, 95% confidence interval 1.1-5.1, P  =  .03. Comparing patients without IGF1R overexpression to those with overexpression, 5-year PFS was 94.1% vs 45.8%. IGF1R overexpression was associated with inferior PFS in penile cancer. Drugs that target IGF1R and downstream messengers may have a therapeutic benefit in patients that exhibit IGF1R overexpression. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. Targeting the Insulin-Like Growth Factor 1 Receptor in Ewing's Sarcoma: Reality and Expectations

    Directory of Open Access Journals (Sweden)

    David Olmos

    2011-01-01

    Full Text Available Ewing's sarcoma family of tumours comprises a group of very aggressive diseases that are potentially curable with multimodality treatment. Despite the undoubted success of current treatment, approximately 30% of patients will relapse and ultimately die of disease. The insulin-like growth factor 1 receptor (IGF-1R has been implicated in the genesis, growth, proliferation, and the development of metastatic disease in Ewing's sarcoma. In addition, IGF1-R has been validated, both in vitro and in vivo, as a potential therapeutic target in Ewing's sarcoma. Phase I studies of IGF-1R monoclonal antibodies reported several radiological and clinical responses in Ewing's sarcoma patients, and initial reports of several Phase II studies suggest that about a fourth of the patients would benefit from IGF-1R monoclonal antibodies as single therapy, with approximately 10% of patients achieving objective responses. Furthermore, these therapies are well tolerated, and thus far severe toxicity has been rare. Other studies assessing IGF-1R monoclonal antibodies in combination with traditional cytotoxics or other targeted therapies are expected. Despite, the initial promising results, not all patients benefit from IGF-1R inhibition, and consequently, there is an urgent need for the identification of predictive markers of response.

  1. Targeting the Insulin-Like Growth Factor 1 Receptor in Ewing's Sarcoma: Reality and Expectations

    Science.gov (United States)

    Olmos, David; Martins, Ana Sofia; Jones, Robin L.; Alam, Salma; Scurr, Michelle; Judson, Ian R.

    2011-01-01

    Ewing's sarcoma family of tumours comprises a group of very aggressive diseases that are potentially curable with multimodality treatment. Despite the undoubted success of current treatment, approximately 30% of patients will relapse and ultimately die of disease. The insulin-like growth factor 1 receptor (IGF-1R) has been implicated in the genesis, growth, proliferation, and the development of metastatic disease in Ewing's sarcoma. In addition, IGF1-R has been validated, both in vitro and in vivo, as a potential therapeutic target in Ewing's sarcoma. Phase I studies of IGF-1R monoclonal antibodies reported several radiological and clinical responses in Ewing's sarcoma patients, and initial reports of several Phase II studies suggest that about a fourth of the patients would benefit from IGF-1R monoclonal antibodies as single therapy, with approximately 10% of patients achieving objective responses. Furthermore, these therapies are well tolerated, and thus far severe toxicity has been rare. Other studies assessing IGF-1R monoclonal antibodies in combination with traditional cytotoxics or other targeted therapies are expected. Despite, the initial promising results, not all patients benefit from IGF-1R inhibition, and consequently, there is an urgent need for the identification of predictive markers of response. PMID:21647361

  2. CRDB: database of chemosensory receptor gene families in vertebrate.

    Directory of Open Access Journals (Sweden)

    Dong Dong

    Full Text Available Chemosensory receptors (CR are crucial for animals to sense the environmental changes and survive on earth. The emergence of whole-genome sequences provides us an opportunity to identify the entire CR gene repertoires. To completely gain more insight into the evolution of CR genes in vertebrates, we identified the nearly all CR genes in 25 vertebrates using homology-based approaches. Among these CR gene repertoires, nearly half of them were identified for the first time in those previously uncharacterized species, such as the guinea pig, giant panda and elephant, etc. Consistent with previous findings, we found that the numbers of CR genes vary extensively among different species, suggesting an extreme form of 'birth-and-death' evolution. For the purpose of facilitating CR gene analysis, we constructed a database with the goals to provide a resource for CR genes annotation and a web tool for exploring their evolutionary patterns. Besides a search engine for the gene extraction from a specific chromosome region, an easy-to-use phylogenetic analysis tool was also provided to facilitate online phylogeny study of CR genes. Our work can provide a rigorous platform for further study on the evolution of CR genes in vertebrates.

  3. Overexpression of the ped/pea-15 Gene Causes Diabetes by Impairing Glucose-Stimulated Insulin Secretion in Addition to Insulin Action

    OpenAIRE

    Vigliotta, Giovanni; Miele, Claudia; Santopietro, Stefania; Portella, Giuseppe; Perfetti, Anna; Maitan, Maria Alessandra; Cassese, Angela; Oriente, Francesco; Trencia, Alessandra; Fiory, Francesca; Romano, Chiara; Tiveron, Cecilia; Tatangelo, Laura; Troncone, Giancarlo; Formisano, Pietro

    2004-01-01

    Overexpression of the ped/pea-15 gene is a common feature of type 2 diabetes. In the present work, we show that transgenic mice ubiquitously overexpressing ped/pea-15 exhibited mildly elevated random-fed blood glucose levels and decreased glucose tolerance. Treatment with a 60% fat diet led ped/pea-15 transgenic mice to develop diabetes. Consistent with insulin resistance in these mice, insulin administration reduced glucose levels by only 35% after 45 min, compared to 70% in control mice. In...

  4. Haploinsufficiency in the PPARα and LDL receptor genes leads to gender- and age-specific obesity and hyperinsulinemia

    International Nuclear Information System (INIS)

    Sugiyama, Eiko; Tanaka, Naoki; Nakajima, Tamie; Kamijo, Yuji; Yokoyama, Shin; Li Yufeng; Gonzalez, Frank J.; Aoyama, Toshifumi

    2006-01-01

    When preparing peroxisome proliferator-activated receptor (PPAR)α:low-density lipoprotein receptor (LDLR) (-/-) double knockout mice, we unexpectedly found a unique gender- and age-specific obesity in the F1 generation, PPARα (+/-):LDLR (+/-), even in mice fed standard chow. Body weights of the male heterozygous mice increased up to about 60 g at 75 weeks of age, then decreased by about 30 g at 100 weeks of age. More than 95% of the heterozygous mice between 35- and 75-week-olds were overweight. Of interest, the obese heterozygous mice also exhibited hyperinsulinemia correlating with moderate insulin resistance. Hepatic gene expression of LDLR was lower than expected in the heterozygous mice, particularly at 50 and 75 weeks of age. In contrast, the hepatic expression of PPARα was higher than expected in obese heterozygous mice, but decreased in non-obese older heterozygous mice. Modulated expression of these genes may be partially associated with the onset of the hyperinsulinemia

  5. Adipose tissue insulin receptor and glucose transporter 4 expression, and blood glucose and insulin responses during glucose tolerance tests in transition Holstein cows with different body condition.

    Science.gov (United States)

    Jaakson, H; Karis, P; Ling, K; Ilves-Luht, A; Samarütel, J; Henno, M; Jõudu, I; Waldmann, A; Reimann, E; Pärn, P; Bruckmaier, R M; Gross, J J; Kaart, T; Kass, M; Ots, M

    2018-01-01

    Glucose uptake in tissues is mediated by insulin receptor (INSR) and glucose transporter 4 (GLUT4). The aim of this study was to examine the effect of body condition during the dry period on adipose tissue mRNA and protein expression of INSR and GLUT4, and on the dynamics of glucose and insulin following the i.v. glucose tolerance test in Holstein cows 21 d before (d -21) and after (d 21) calving. Cows were grouped as body condition score (BCS) ≤3.0 (thin, T; n = 14), BCS = 3.25 to 3.5 (optimal, O; n = 14), and BCS ≥3.75 (overconditioned, OC; n = 14). Blood was analyzed for glucose, insulin, fatty acids, and β-hydroxybutyrate concentrations. Adipose tissue was analyzed for INSR and GLUT4 mRNA and protein concentrations. During the glucose tolerance test 0.15 g/kg of body weight glucose was infused; blood was collected at -5, 5, 10, 20, 30, 40, 50, and 60 min, and analyzed for glucose and insulin. On d -21 the area under the curve (AUC) of glucose was smallest in group T (1,512 ± 33.9 mg/dL × min) and largest in group OC (1,783 ± 33.9 mg/dL × min), and different between all groups. Basal insulin on d -21 was lowest in group T (13.9 ± 2.32 µU/mL), which was different from group OC (24.9 ± 2.32 µU/mL. On d -21 the smallest AUC 5-60 of insulin in group T (5,308 ± 1,214 µU/mL × min) differed from the largest AUC in group OC (10,867 ± 1,215 µU/mL × min). Time to reach basal concentration of insulin in group OC (113 ± 14.1 min) was longer compared with group T (45 ± 14.1). The INSR mRNA abundance on d 21 was higher compared with d -21 in groups T (d -21: 3.3 ± 0.44; d 21: 5.9 ± 0.44) and O (d -21: 3.7 ± 0.45; d 21: 4.7 ± 0.45). The extent of INSR protein expression on d -21 was highest in group T (7.3 ± 0.74 ng/mL), differing from group O (4.6 ± 0.73 ng/mL), which had the lowest expression. The amount of GLUT4 protein on d -21 was lowest in group OC (1.2 ± 0.14 ng/mL), different from group O (1.8 ± 0.14 ng/mL), which had the highest amount

  6. Metabolic syndrome and related variables, insulin resistance, leptin levels, and PPAR-γ2 and leptin gene polymorphisms in a pedigree of subjects with bipolar disorder

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    Trino Baptista

    2015-06-01

    Full Text Available Objective:Evidence points to a high prevalence of metabolic dysfunction in bipolar disorder (BD, but few studies have evaluated the relatives of subjects with BD. We conducted a cross-sectional study in an extended family of patients with BD type I.Methods:The available relatives of the same family were interviewed (DSM-IV-R and assessed in fasting conditions for body mass index, constituent variables of the metabolic syndrome (MS, leptin levels, insulin resistance index, and single nucleotide polymorphisms (SNPs for the leptin receptor and promoter and PPAR-γ2 genes. The frequency of MS was compared with that recorded in the local general population.Results:Ninety-three relatives of three adults with BD were evaluated (30 aged 18 years. The frequency of MS was similar to that of the general population. Significantly higher frequencies of abnormal glucose, total and low density cholesterol (LDL-c levels (all p < 0.05, waist circumference (p = 0.057, and leptin and insulin resistance values (in adults only were observed in the family. Adults with the QQ genotype of the leptin receptor displayed higher LDL-c levels than carriers of the R allele.Conclusions:The associations among BD consanguinity, familial hypercholesterolemia, and leptin receptor SNPs reported herein should be replicated and extended in other pedigrees.

  7. Mu Opioid Receptor Gene: New Point Mutations in Opioid Addicts

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    Amin Dinarvand

    2014-02-01

    Full Text Available Introduction: Association between single-nucleotide polymorphisms (SNPs in mu opioid receptor gene and drug addiction has been shown in various studies. Here, we have evaluated the existence of polymorphisms in exon 3 of this gene in Iranian population and investigated the possible association between these mutations and opioid addiction.  Methods: 79 opioid-dependent subjects (55 males, 24 females and 134 non-addict or control individuals (74 males, 60 females participated in the study. Genomic DNA was extracted from volunteers’ peripheral blood and exon 3 of the mu opioid receptor gene was amplified by polymerase chain reaction (PCR whose products were then sequenced.  Results: Three different heterozygote polymorphisms were observed in 3 male individuals: 759T>C and 877G>A mutations were found in 2 control volunteers and 1043G>C substitution was observed in an opioid-addicted subject. Association between genotype and opioid addiction for each mutation was not statistically significant.  Discussion: It seems that the sample size used in our study is not enough to confirm or reject any association between 759T>C, 877G>A and 1043G>C substitutions in exon 3 of the mu opioid receptor gene and opioid addiction susceptibility in Iranian population.

  8. The Role of Type I Insulin Like Growth Factor Receptor (IGF-IR) in Adult and Childhood Acute Lymphoblastic Leukemia

    International Nuclear Information System (INIS)

    KAMEL, M.M.; HAMMAM, A.A.; ELHOSEINY, Sh.M.; MOKHLES, A.; MOHSEN, E.

    2008-01-01

    Background: Type 1 insulin like growth factor receptor (IGF-IR) is over expressed in many tumors including hematological cancers. It is a critical signaling molecule for tumor cell proliferation and survival. Data suggest that IGF-IR antibodies can effectively and specifically inhibit cancer cell growth in vitro and in vivo. Blockage of IGF-IR expression could be a promising therapeutic approach for the management of cancer patients. Aim of Work: To characterize the expression pattern of IGF-IR gene in malignant lymphoblasts of children and adults suffering from ALL in relation to clinical features at diagnosis. Patients and Methods: The expression of IGF-IR was analyzed in 60 patients with ALL, 30 childhood ALL (16 newly diagnosed and 14 in complete remission) and 30 adulthood ALL (15 newly diagnosed and 15 in complete remission) together with 20 normal age and sex matched healthy controls using a Real-Time Quantitative Reverse- Transcriptase Polymerase Chain Reaction (RTQ-PCR) to assess the possible relation, association or correlation between IGF-IR expression and ALL clinical and laboratory features at diagnosis. Results: IGF-IR was expressed in all 60 patients with ALL; the expression levels of IGF-IR were significantly higher in newly diagnosed patients than in patients in complete remission (CR) and controls (p<0.001). There were no statistically significant differences in the expression of IGF-IR between patients with different clinical and laboratory features. Conclusion: IGF-1R seems to play a crucial role in patients with ALL since it is expressed in all ALL cases (adulthood and childhood). Therefore, new therapeutic agents targeting IGF-1R may provide a better chance for those patients

  9. Linkage of the VNTR/insulin-gene and type I diabetes mellitus: Increased gene sharing in affected sibling pairs

    Energy Technology Data Exchange (ETDEWEB)

    Owerbach, D.; Gabbay, K.H. (Baylor College of Medicine, Houston, TX (United States))

    1994-05-01

    Ninety-six multiplex type I diabetic families were typed at the 5' flanking region of the insulin gene by using a PCR assay that better resolves the VNTR into multiple alleles. Affected sibling pairs shared 2, 1, and 0 VNTR alleles - identical by descent - at a frequency of .47, .45, and .08, respectively, a ratio that deviated from the expected 1:2:1 ratio (P<.001). These results confirm linkage of the chromosome 11p15.5 region with type I diabetes mellitus susceptibility. 20 refs., 2 tabs.

  10. The L-alpha-amino acid receptor GPRC6A is expressed in the islets of Langerhans but is not involved in L-arginine-induced insulin release

    DEFF Research Database (Denmark)

    Smajilovic, Sanela; Clemmensen, Christoffer; Johansen, Lars Dan

    2013-01-01

    insulin secretion; therefore, the receptor has been hypothesized to have a role in regulating glucose metabolism. In this study, we demonstrate that GPRC6A is expressed in islets of Langerhans, but activation of the receptor by L-arginine did not stimulate insulin secretion. We also investigated central...... metabolic parameters in GPRC6A knockout mice compared with wildtype littermates and found no difference in glucose metabolism or body fat percentage when mice were administered a standard chow diet. In conclusion, our data do not support a role for GPRC6A in L-arginine-induced insulin release and glucose...

  11. Drosophila insulin-producing cells are differentially modulated by serotonin and octopamine receptors and affect social behavior.

    Directory of Open Access Journals (Sweden)

    Jiangnan Luo

    Full Text Available A set of 14 insulin-producing cells (IPCs in the Drosophila brain produces three insulin-like peptides (DILP2, 3 and 5. Activity in IPCs and release of DILPs is nutrient dependent and controlled by multiple factors such as fat body-derived proteins, neurotransmitters, and neuropeptides. Two monoamine receptors, the octopamine receptor OAMB and the serotonin receptor 5-HT1A, are expressed by the IPCs. These receptors may act antagonistically on adenylate cyclase. Here we investigate the action of the two receptors on activity in and output from the IPCs. Knockdown of OAMB by targeted RNAi led to elevated Dilp3 transcript levels in the brain, whereas 5-HT1A knockdown resulted in increases of Dilp2 and 5. OAMB-RNAi in IPCs leads to extended survival of starved flies and increased food intake, whereas 5-HT1A-RNAi produces the opposite phenotypes. However, knockdown of either OAMB or 5-HT1A in IPCs both lead to increased resistance to oxidative stress. In assays of carbohydrate levels we found that 5-HT1A knockdown in IPCs resulted in elevated hemolymph glucose, body glycogen and body trehalose levels, while no effects were seen after OAMB knockdown. We also found that manipulations of the two receptors in IPCs affected male aggressive behavior in different ways and 5-HT1A-RNAi reduced courtship latency. Our observations suggest that activation of 5-HT1A and OAMB signaling in IPCs generates differential effects on Dilp transcription, fly physiology, metabolism and social interactions. However the findings do not support an antagonistic action of the two monoamines and their receptors in this particular system.

  12. Drosophila insulin-producing cells are differentially modulated by serotonin and octopamine receptors and affect social behavior.

    Science.gov (United States)

    Luo, Jiangnan; Lushchak, Oleh V; Goergen, Philip; Williams, Michael J; Nässel, Dick R

    2014-01-01

    A set of 14 insulin-producing cells (IPCs) in the Drosophila brain produces three insulin-like peptides (DILP2, 3 and 5). Activity in IPCs and release of DILPs is nutrient dependent and controlled by multiple factors such as fat body-derived proteins, neurotransmitters, and neuropeptides. Two monoamine receptors, the octopamine receptor OAMB and the serotonin receptor 5-HT1A, are expressed by the IPCs. These receptors may act antagonistically on adenylate cyclase. Here we investigate the action of the two receptors on activity in and output from the IPCs. Knockdown of OAMB by targeted RNAi led to elevated Dilp3 transcript levels in the brain, whereas 5-HT1A knockdown resulted in increases of Dilp2 and 5. OAMB-RNAi in IPCs leads to extended survival of starved flies and increased food intake, whereas 5-HT1A-RNAi produces the opposite phenotypes. However, knockdown of either OAMB or 5-HT1A in IPCs both lead to increased resistance to oxidative stress. In assays of carbohydrate levels we found that 5-HT1A knockdown in IPCs resulted in elevated hemolymph glucose, body glycogen and body trehalose levels, while no effects were seen after OAMB knockdown. We also found that manipulations of the two receptors in IPCs affected male aggressive behavior in different ways and 5-HT1A-RNAi reduced courtship latency. Our observations suggest that activation of 5-HT1A and OAMB signaling in IPCs generates differential effects on Dilp transcription, fly physiology, metabolism and social interactions. However the findings do not support an antagonistic action of the two monoamines and their receptors in this particular system.

  13. FOXC2 mRNA Expression and a 5' untranslated region polymorphism of the gene are associated with insulin resistance

    DEFF Research Database (Denmark)

    Ridderstråle, Martin; Carlsson, Emma; Klannemark, Mia

    2002-01-01

    with subcutaneous fat from obese subjects (12 +/- 4-fold; P = 0.0001), and there was a correlation between whole-body insulin sensitivity and FOXC2 mRNA levels in visceral fat (fS-insulin R = -0.64, P = 0.01, and homeostasis model assessment of insulin resistance [HOMA-IR] R = -0.68, P = 0.007) and skeletal muscle...... (fS-insulin R = -0.57, P = 0.03, and HOMA-IR R = -0.55, P = 0.04). Mutation screening of the FOXC2 gene identified a common polymorphism in the 5' untranslated region (C-512T). The T allele was associated with enhanced insulin sensitivity (HOMA-IR P = 0.007) and lower plasma triglyceride levels...

  14. The Role of Insulin, Insulin Growth Factor, and Insulin-Degrading Enzyme in Brain Aging and Alzheimer's Disease

    OpenAIRE

    Messier, Claude; Teutenberg, Kevin

    2005-01-01

    Most brain insulin comes from the pancreas and is taken up by the brain by what appears to be a receptor-based carrier. Type 2 diabetes animal models associated with insulin resistance show reduced insulin brain uptake and content. Recent data point to changes in the insulin receptor cascade in obesity-related insulin resistance, suggesting that brain insulin receptors also become less sensitive to insulin, which could reduce synaptic plasticity. Insulin transport to the brain is reduced in a...

  15. Human circulating monocytes internalize 125I-insulin in a similar fashion to rat hepatocytes: relevance to receptor regulation in target and nontarget tissues

    International Nuclear Information System (INIS)

    Grunberger, G.; Robert, A.; Carpentier, J.L.; Dayer, J.M.; Roth, A.; Stevenson, H.C.; Orci, L.; Gorden, P.

    1985-01-01

    Circulating monocytes bind 125 I-insulin in a specific fashion and have been used to analyze the ambient receptor status in humans. When freshly isolated circulating monocytes are incubated with 125 I-insulin and examined by electron microscopic autoradiography, approximately 18% of the labeled material is internalized after 15 minutes at 37 degrees C. By 2 hours at 37 degrees C, approximately one half of the 125 I-insulin is internalized. Internalization occurs also at 15 degrees C but at a slower rate. Furthermore, the monocytes bind and internalize 125 I-insulin in a manner that mirrors that of major target tissues, such as rat hepatocytes. These data suggest that the insulin receptor of the circulating monocyte might be regulated by adsorptive endocytosis in a manner analogous to that of target tissue, such as the liver

  16. Identification of novel androgen receptor target genes in prostate cancer

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    Gerald William L

    2007-06-01

    Full Text Available Abstract Background The androgen receptor (AR plays critical roles in both androgen-dependent and castrate-resistant prostate cancer (PCa. However, little is known about AR target genes that mediate the receptor's roles in disease progression. Results Using Chromatin Immunoprecipitation (ChIP Display, we discovered 19 novel loci occupied by the AR in castrate resistant C4-2B PCa cells. Only four of the 19 AR-occupied regions were within 10-kb 5'-flanking regulatory sequences. Three were located up to 4-kb 3' of the nearest gene, eight were intragenic and four were in gene deserts. Whereas the AR occupied the same loci in C4-2B (castrate resistant and LNCaP (androgen-dependent PCa cells, differences between the two cell lines were observed in the response of nearby genes to androgens. Among the genes strongly stimulated by DHT in C4-2B cells – D-dopachrome tautomerase (DDT, Protein kinase C delta (PRKCD, Glutathione S- transferase theta 2 (GSTT2, Transient receptor potential cation channel subfamily V member 3 (TRPV3, and Pyrroline-5-carboxylate reductase 1 (PYCR1 – most were less strongly or hardly stimulated in LNCaP cells. Another AR target gene, ornithine aminotransferase (OAT, was AR-stimulated in a ligand-independent manner, since it was repressed by AR siRNA knockdown, but not stimulated by DHT. We also present evidence for in vivo AR-mediated regulation of several genes identified by ChIP Display. For example, PRKCD and PYCR1, which may contribute to PCa cell growth and survival, are expressed in PCa biopsies from primary tumors before and after ablation and in metastatic lesions in a manner consistent with AR-mediated stimulation. Conclusion AR genomic occupancy is similar between LNCaP and C4-2B cells and is not biased towards 5' gene flanking sequences. The AR transcriptionally regulates less than half the genes nearby AR-occupied regions, usually but not always, in a ligand-dependent manner. Most are stimulated and a few are

  17. Prolonged Treatment with Free Fatty Acids has Post Receptor Effect in Hepatic Insulin Resistance: Evidence that Fatty Acids, Oleate and Palmitate have Insignificant Effect on the Insulin Receptor Beta In Vivo and Ex Vivo Primary Hepatocytes

    Directory of Open Access Journals (Sweden)

    Rafik Ragheb

    2009-01-01

    Full Text Available In the current study, we used immunoprecipitation and immunoblotting to examine the levels and phosphorylation status of the insulin receptor-beta subunit (IR-β, as well as the down stream target in PI3K pathway, total PKB/Akt as well as their phosphorylated forms. The assessment of FFAs treatment showed no direct and significant effect on the PI3K stimulation, specifically the IR-β in primary hepatic control cells treated with insulin. Cells treated with either oleate or palmitate (360 µM showed no statistically significant values following insulin stimulation (P > 0.05. To further investigate the effect of both FFAs and high insulin (1 µg, we examined the effects of oleate and palmitate at 360 µM concentration on IR-β as well as PKB. There was no significant difference in the total protein levels and their phosphorylated forms in cells treated with or without oleate or plamitate. Interestingly, IR-β tyrosine phosphorylation showed a similar insignificant effect in vivo and ex vivo hepatic cells treated with oleate or palmitate in comparison to their controls in the fructose fed hamsters.

  18. Bioluminescence imaging of β cells and intrahepatic insulin gene activity under normal and pathological conditions.

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    Tokio Katsumata

    Full Text Available In diabetes research, bioluminescence imaging (BLI has been applied in studies of β-cell impairment, development, and islet transplantation. To develop a mouse model that enables noninvasive imaging of β cells, we generated a bacterial artificial chromosome (BAC transgenic mouse in which a mouse 200-kbp genomic fragment comprising the insulin I gene drives luciferase expression (Ins1-luc BAC transgenic mouse. BLI of mice was performed using the IVIS Spectrum system after intraperitoneal injection of luciferin, and the bioluminescence signal from the pancreatic region analyzed. When compared with MIP-Luc-VU mice [FVB/N-Tg(Ins1-lucVUPwrs/J] expressing luciferase under the control of the 9.2-kbp mouse insulin I promoter (MIP, the bioluminescence emission from Ins1-luc BAC transgenic mice was enhanced approximately 4-fold. Streptozotocin-treated Ins1-luc BAC transgenic mice developed severe diabetes concomitant with a sharp decline in the BLI signal intensity in the pancreas. Conversely, mice fed a high-fat diet for 8 weeks showed an increase in the signal, reflecting a decrease or increase in the β-cell mass. Although the bioluminescence intensity of the islets correlated well with the number of isolated islets in vitro, the intensity obtained from a living mouse in vivo did not necessarily reflect an absolute quantification of the β-cell mass under pathological conditions. On the other hand, adenovirus-mediated gene transduction of β-cell-related transcription factors in Ins1-luc BAC transgenic mice generated luminescence from the hepatic region for more than 1 week. These results demonstrate that BLI in Ins1-luc BAC transgenic mice provides a noninvasive method of imaging islet β cells and extrapancreatic activity of the insulin gene in the liver under normal and pathological conditions.

  19. Dynamic evolution of bitter taste receptor genes in vertebrates

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    Jones Gareth

    2009-01-01

    Full Text Available Abstract Background Sensing bitter tastes is crucial for many animals because it can prevent them from ingesting harmful foods. This process is mainly mediated by the bitter taste receptors (T2R, which are largely expressed in the taste buds. Previous studies have identified some T2R gene repertoires, and marked variation in repertoire size has been noted among species. However, the mechanisms underlying the evolution of vertebrate T2R genes remain poorly understood. Results To better understand the evolutionary pattern of these genes, we identified 16 T2R gene repertoires based on the high coverage genome sequences of vertebrates and studied the evolutionary changes in the number of T2R genes during birth-and-death evolution using the reconciled-tree method. We found that the number of T2R genes and the fraction of pseudogenes vary extensively among species. Based on the results of phylogenetic analysis, we showed that T2R gene families in teleost fishes are more diverse than those in tetrapods. In addition to the independent gene expansions in teleost fishes, frogs and mammals, lineage-specific gene duplications were also detected in lizards. Furthermore, extensive gains and losses of T2R genes were detected in each lineage during their evolution, resulting in widely differing T2R gene repertoires. Conclusion These results further support the hypotheses that T2R gene repertoires are closely related to the dietary habits of different species and that birth-and-death evolution is associated with adaptations to dietary changes.

  20. 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

  1. Uteroplacental insufficiency down regulates insulin receptor and affects expression of key enzymes of long-chain fatty acid (LCFA metabolism in skeletal muscle at birth

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    Puglianiello Antonella

    2008-05-01

    Full Text Available Abstract Background Epidemiological studies have revealed a relationship between early growth restriction and the subsequent development of insulin resistance and type 2 diabetes. Ligation of the uterine arteries in rats mimics uteroplacental insufficiency and serves as a model of intrauterine growth restriction (IUGR and subsequent developmental programming of impaired glucose tolerance, hyperinsulinemia and adiposity in the offspring. The objective of this study was to investigate the effects of uterine artery ligation on the skeletal muscle expression of insulin receptor and key enzymes of LCFA metabolism. Methods Bilateral uterine artery ligation was performed on day 19 of gestation in Sprague-Dawley pregnant rats. Muscle of the posterior limb was dissected at birth and processed by real-time RT-PCR to analyze the expression of insulin receptor, ACCα, ACCβ (acetyl-CoA carboxylase alpha and beta subunits, ACS (acyl-CoA synthase, AMPK (AMP-activated protein kinase, alpha2 catalytic subunit, CPT1B (carnitine palmitoyltransferase-1 beta subunit, MCD (malonyl-CoA decarboxylase in 14 sham and 8 IUGR pups. Muscle tissue was treated with lysis buffer and Western immunoblotting was performed to assay the protein content of insulin receptor and ACC. Results A significant down regulation of insulin receptor protein (p Conclusion Our data suggest that uteroplacental insufficiency may affect skeletal muscle metabolism down regulating insulin receptor and reducing the expression of key enzymes involved in LCFA formation and oxidation.

  2. Rosiglitazone treatment of patients with extreme insulin resistance and diabetes mellitus due to insulin receptor mutations has no effects on glucose and lipid metabolism

    DEFF Research Database (Denmark)

    Vestergaard, H; Lund, S; Pedersen, O

    2001-01-01

    Rosiglitazone, a thiazolidinedione (TZD), increases insulin sensitivity by reducing levels of plasma NEFA, triglycerides (TG), glucose and serum insulin. Rosiglitazone treatment decreases insulin resistance in type 2 diabetic patients, but no data exist concerning rosiglitazone treatment...

  3. Replicated Risk Nicotinic Cholinergic Receptor Genes for Nicotine Dependence

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    Lingjun Zuo

    2016-11-01

    Full Text Available It has been hypothesized that the nicotinic acetylcholine receptors (nAChRs play important roles in nicotine dependence (ND and influence the number of cigarettes smoked per day (CPD in smokers. We compiled the associations between nicotinic cholinergic receptor genes (CHRNs and ND/CPD that were replicated across different studies, reviewed the expression of these risk genes in human/mouse brains, and verified their expression using independent samples of both human and mouse brains. The potential functions of the replicated risk variants were examined using cis-eQTL analysis or predicted using a series