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Sample records for mtor signaling pathway

  1. The mTOR signalling pathway in cancer and the potential mTOR inhibitory activities of natural phytochemicals.

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    Tan, Heng Kean; Moad, Ahmed Ismail Hassan; Tan, Mei Lan

    2014-01-01

    The mammalian target of rapamycin (mTOR) kinase plays an important role in regulating cell growth and cell cycle progression in response to cellular signals. It is a key regulator of cell proliferation and many upstream activators and downstream effectors of mTOR are known to be deregulated in various types of cancers. Since the mTOR signalling pathway is commonly activated in human cancers, many researchers are actively developing inhibitors that target key components in the pathway and some of these drugs are already on the market. Numerous preclinical investigations have also suggested that some herbs and natural phytochemicals, such as curcumin, resveratrol, timosaponin III, gallic acid, diosgenin, pomegranate, epigallocatechin gallate (EGCC), genistein and 3,3'-diindolylmethane inhibit the mTOR pathway either directly or indirectly. Some of these natural compounds are also in the clinical trial stage. In this review, the potential anti-cancer and chemopreventive activities and the current status of clinical trials of these phytochemicals are discussed.

  2. BMAL1-dependent regulation of the mTOR signaling pathway delays aging.

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    Khapre, Rohini V; Kondratova, Anna A; Patel, Sonal; Dubrovsky, Yuliya; Wrobel, Michelle; Antoch, Marina P; Kondratov, Roman V

    2014-01-01

    The circadian clock, an internal time-keeping system, has been linked with control of aging, but molecular mechanisms of regulation are not known. BMAL1 is a transcriptional factor and core component of the circadian clock; BMAL1 deficiency is associated with premature aging and reduced lifespan. Here we report that activity of mammalian Target of Rapamycin Complex 1 (mTORC1) is increased upon BMAL1 deficiency both in vivo and in cell culture. Increased mTOR signaling is associated with accelerated aging; in accordance with that, treatment with the mTORC1 inhibitor rapamycin increased lifespan of Bmal1-/- mice by 50%. Our data suggest that BMAL1 is a negative regulator of mTORC1 signaling. We propose that the circadian clock controls the activity of the mTOR pathway through BMAL1-dependent mechanisms and this regulation is important for control of aging and metabolism.

  3. Mechanisms of amino acid sensing in mTOR signaling pathway

    OpenAIRE

    Kim, Eunjung

    2009-01-01

    Amino acids are fundamental nutrients for protein synthesis and cell growth (increase in cell size). Recently, many compelling evidences have shown that the level of amino acids is sensed by extra- or intra-cellular amino acids sensor(s) and regulates protein synthesis/degradation. Mammalian target of rapamycin complex 1 (mTORC1) is placed in a central position in cell growth regulation and dysregulation of mTOR signaling pathway has been implicated in many serious human diseases including ca...

  4. Leucine minimizes denervation-induced skeletal muscle atrophy of rats through akt/mtor signaling pathways

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    Carolina Barbosa Ribeiro

    2015-03-01

    Full Text Available The aim of the present study was to evaluate the effect of leucine treatment (0.30 mM on muscle weight and signaling of myoproteins related to synthesis and degradation pathways of soleus muscle following seven days of complete sciatic nerve lesion.Wistar rats (n=24 of 3 to 4 months of age (192 ± 23 g were used. The animals were randomly distributed into four experimental groups (n=6/group: control, treated with leucine (L, denervated (D and denervated treated with leucine (DL.Dependent measures were proteins levels of AKT, AMPK, mTOR, and ACC performed by Western blot. Leucine induced a reduction in the phosphorylation of AMPK (p<0.05 by 16% in the L and by 68% in the DL groups as compared with control group. Denervation increased AMPK by 24% in the D group as compared with the control group (p<0.05. AKT was also modulated by denervation and leucine treatment, highlighted by the elevation of AKT phosphorylation in the D (65%, L (98% and DL (146% groups as compared with the control group (p<0.05. AKT phosphorylation was 49% higher in the D group as compared with the DL group.Furthermore, denervation decreased mTOR phosphorylation by 29% in the D group as compared with the control group. However, leucine treatment induced an increase of 49% in the phosphorylation of mTOR in the L group as compared with the control group, and an increase of 154% in the DL as compared with the D group ( p<0.05. ACC phosphorylation was 20% greater in the D group than the control group. Furthermore, ACC in the soleus was 22% lower in the in the L group and 50% lower in the DL group than the respective control group (p<0.05.In conclusion, leucine treatment minimized the deleterious effects of denervation on rat soleus muscle by increasing anabolic (AKT and mTOR and decreasing catabolic (AMPK pathways. These results may be interesting for muscle recovery following acute denervation, which may contribute to musculoskeletal rehabilitation after denervation.

  5. mTOR signaling promotes foam cell formation and inhibits foam cell egress through suppressing the SIRT1 signaling pathway.

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    Zheng, Haixiang; Fu, Yucai; Huang, Yusheng; Zheng, Xinde; Yu, Wei; Wang, Wei

    2017-09-01

    Atherosclerosis (AS) is a chronic immuno‑inflammatory disease accompanied by dyslipidemia. The authors previously demonstrated that sirtuin 1 (SIRT1) may prevent atherogenesis through influencing the liver X receptor/C‑C chemokine receptor type 7/nuclear factor‑κB (LXR‑CCR7/NF‑κB) signaling pathway. Previous studies have suggested a role for mammalian target of rapamycin (mTOR) signaling in the pathogenesis of cardiovascular diseases. The present study investigated the potential association between mTOR signaling and SIRT1‑LXR‑CCR7/NF‑κB signaling (SIRT1 signaling) in AS pathogenesis. To induce foam cell formation, U937 cells were differentiated into macrophages by exposure to phorbol 12‑myristate 13‑acetate (PMA) for 24 h, followed by treatment with palmitate and oxidized low density lipoprotein for a further 24 h. Oil red O staining revealed a large accumulation of lipid droplets present in foam cells. Western blot analysis demonstrated increased protein levels of phosphorylated (p)‑mTOR and its downstream factor p‑ribosomal protein S6 kinase (p70S6K). Reverse transcription‑quantitative polymerase chain reaction and western blot analyses additionally revealed decreased expression of SIRT1, LXRα and CCR7 and increased expression of NF‑κB and its downstream factor tumor necrosis factor‑α (TNF‑α) in an atherogenetic condition induced by lysophosphatidic acid (LPA). In addition, abundant lipid droplets accumulated in U937‑LPA‑treated foam cells. Rapamycin, an mTOR inhibitor, suppressed the expression and activity of mTOR and p70S6K, however enhanced expression of SIRT1, LXRα, and CCR7. Conversely, rapamycin deceased TNF‑α and NF‑κB activity, the latter of which was further confirmed by immunofluorescence analysis demonstrating increased levels of NF‑κB present in the cytoplasm compared with the nucleus. The findings of the present study suggest that mTOR signaling promotes foam cell formation and inhibits foam

  6. Inflammatory stress increases hepatic CD36 translational efficiency via activation of the mTOR signalling pathway.

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    Chuan Wang

    Full Text Available Inflammatory stress is an independent risk factor for the development of non-alcoholic fatty liver disease (NAFLD. Although CD36 is known to facilitate long-chain fatty acid uptake and contributes to NAFLD progression, the mechanisms that link inflammatory stress to hepatic CD36 expression and steatosis remain unclear. As the mammalian target of rapamycin (mTOR signalling pathway is involved in CD36 translational activation, this study was undertaken to investigate whether inflammatory stress enhances hepatic CD36 expression via mTOR signalling pathway and the underlying mechanisms. To induce inflammatory stress, we used tumour necrosis factor alpha (TNF-α and interleukin-6 (IL-6 stimulation of the human hepatoblastoma HepG2 cells in vitro and casein injection in C57BL/6J mice in vivo. The data showed that inflammatory stress increased hepatic CD36 protein levels but had no effect on mRNA expression. A protein degradation assay revealed that CD36 protein stability was not different between HepG2 cells treated with or without TNF-α or IL-6. A polysomal analysis indicated that CD36 translational efficiency was significantly increased by inflammatory stress. Additionally, inflammatory stress enhanced the phosphorylation of mTOR and its downstream translational regulators including p70S6K, 4E-BP1 and eIF4E. Rapamycin, an mTOR-specific inhibitor, reduced the phosphorylation of mTOR signalling pathway and decreased the CD36 translational efficiency and protein level even under inflammatory stress resulting in the alleviation of inflammatory stress-induced hepatic lipid accumulation. This study demonstrates that the activation of the mTOR signalling pathway increases hepatic CD36 translational efficiency, resulting in increased CD36 protein expression under inflammatory stress.

  7. Caloric restriction protects against electrical kindling of the amygdala by inhibiting the mTOR signaling pathway

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    Bryan Victor Phillips-Farfan

    2015-03-01

    Full Text Available Caloric restriction (CR has been shown to possess antiepileptic properties; however its mechanism of action is poorly understood. CR might inhibit the activity of the mammalian or mechanistic target of rapamycin (mTOR signaling cascade, which seems to participate crucially in the generation of epilepsy. Thus, we investigated the effect of CR on the mTOR pathway and whether CR modified epilepsy generation due to electrical amygdala kindling. The former was studied by analyzing the phosphorylation of adenosine monophosphate-activated protein kinase, protein kinase B and the ribosomal protein S6. The mTOR cascade is regulated by energy and by insulin levels, both of which may be changed by CR; thus we investigated if CR altered the levels of energy substrates in the blood or the level of insulin in plasma. Finally, we studied if CR modified the expression of genes that encode proteins participating in the mTOR pathway. CR increased the after-discharge threshold and tended to reduce the after-discharge duration, indicating an anti-convulsive action. CR diminished the phosphorylation of protein kinase B and ribosomal protein S6, suggesting an inhibition of the mTOR cascade. However, CR did not change glucose, β-hydroxybutyrate or insulin levels; thus the effects of CR were independent from them. Interestingly, CR also did not modify the expression of any investigated gene. The results suggest that the anti-epileptic effect of CR may be partly due to inhibition of the mTOR pathway.

  8. Effects of ketamine administration on mTOR and reticulum stress signaling pathways in the brain after the infusion of rapamycin into prefrontal cortex.

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    Abelaira, Helena M; Réus, Gislaine Z; Ignácio, Zuleide M; Dos Santos, Maria Augusta B; de Moura, Airam B; Matos, Danyela; Demo, Júlia P; da Silva, Júlia B I; Michels, Monique; Abatti, Mariane; Sonai, Beatriz; Dal Pizzol, Felipe; Carvalho, André F; Quevedo, João

    2017-04-01

    Recent studies show that activation of the mTOR signaling pathway is required for the rapid antidepressant actions of glutamate N-methyl-D-aspartate (NMDA) receptor antagonists. A relationship between mTOR kinase and the endoplasmic reticulum (ER) stress pathway, also known as the unfolded protein response (UPR) has been shown. We evaluate the effects of ketamine administration on the mTOR signaling pathway and proteins of UPR in the prefrontal cortex (PFC), hippocampus, amygdala and nucleus accumbens, after the inhibiton of mTOR signaling in the PFC. Male adult Wistar rats received pharmacological mTOR inhibitor, rapamycin (0.2 nmol), or vehicle into the PFC and then a single dose of ketamine (15 mg/kg, i.p.). The immunocontent of mTOR, eukaryotic initiation factor 4E-binding protein 1 (4E-BP1), eukaryotic elongation factor 2 kinase (eEF2K) homologous protein (CHOP), PKR-like ER kinase (PERK) and inositol-requiring enzyme 1 (IRE1) - alpha were determined in the brain. The mTOR levels were reduced in the rapamycin group treated with saline and ketamine in the PFC; p4EBP1 levels were reduced in the rapamycin group treated with ketamine in the PFC and nucleus accumbens; the levels of peEF2K were increased in the PFC in the vehicle group treated with ketamine and reduced in the rapamycin group treated with ketamine. The PERK and IRE1-alpha levels were decreased in the PFC in the rapamycin group treated with ketamine. Our results suggest that mTOR signaling inhibition by rapamycin could be involved, at least in part, with the mechanism of action of ketamine; and the ketamine antidepressant on ER stress pathway could be also mediated by mTOR signaling pathway in certain brain structures. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Nanoparticle core stability and surface functionalization drive the mTOR signaling pathway in hepatocellular cell lines

    Czech Academy of Sciences Publication Activity Database

    Lunova, Mariia; Prokhorov, Andriy; Jirsa, M.; Hof, Martin; Olžyńska, Agnieszka; Jurkiewicz, Piotr; Kubinová, Šárka; Lunov, Oleg; Dejneka, Alexandr

    2017-01-01

    Roč. 7, Nov (2017), s. 1-16, č. článku 16049. ISSN 2045-2322 R&D Projects: GA MŠk LO1409; GA MŠk LM2015088 Grant - others:AV ČR(CZ) Fellowship J. E. Purkyně Institutional support: RVO:68378271 ; RVO:61388955 Keywords : nanoparticle core stability * surface functionalization drive * mTOR signaling pathway * hepatocellular cell lines Subject RIV: BO - Biophysics; CF - Physical ; Theoretical Chemistry (UFCH-W) OBOR OECD: Biophysics; Physical chemistry (UFCH-W) Impact factor: 4.259, year: 2016

  10. Long non-coding RNA BCAR4 promotes chondrosarcoma cell proliferation and migration through activation of mTOR signaling pathway.

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    Shui, Xiaolong; Zhou, Chengwei; Lin, Wei; Yu, Yang; Feng, Yongzeng; Kong, Jianzhong

    2017-05-01

    Chondrosarcoma is one of the common malignant histologic tumors, very difficult to treat, but the concrete cause and mechanism have not yet been elucidated. The present study aimed to investigate the functional involvement of BCAR4 in chondrosarcoma and its potentially underlying mechanism. QRT-PCR and western blot were used to determine the expression of BCAR4 and mTOR signaling pathway proteins both in chondrosarcoma tissues and cells. Chondrosarcoma cell proliferation and migration were assessed by MTT assay and transwell migration assay, respectively. The expression vectors were constructed and used to modulate the expression of BCAR4 and mTOR. Chondrosarcoma xenograft mouse model was established by subcutaneous injection with chondrosarcoma cell lines. The tumor volume was monitored to evaluate the effect of BCAR4 on chondrosarcoma cell tumorigenicity. The expressions of BCAR4, p-mTOR and p-P70S6K were up-regulated in chondrosarcoma tissues and cell lines. Moreover, BCAR4 overexpression had significant promoting effect on cell proliferation and migration in chondrosarcoma cells. Furthermore, mTOR signaling pathway was epigenetically activated by BCAR4-induced hyperacetylation of histone H3. We also found that mTOR overexpression abolished the decrease of chondrosarcoma cell proliferation and migration induced by BCAR4 knockdown. In vivo experiments confirmed that BCAR4 overexpression significantly accelerated tumor growth, while the knockdown of BCAR4 significantly inhibited tumor growth. BCAR4 promoted chondrosarcoma cell proliferation and migration through activation of mTOR signaling pathway, and thus contributed to chondrosarcoma progression. Impact statement LncRNA BCAR4 promoted chondrosarcoma cell proliferation and migration through activation of mTOR signaling pathway, and thus contributed to chondrosarcoma progression.

  11. AMP-Activated Protein Kinase Alleviates Extracellular Matrix Accumulation in High Glucose-Induced Renal Fibroblasts through mTOR Signaling Pathway

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    Xia Luo

    2015-01-01

    Full Text Available Background/Aims: Extracellular matrix accumulation contributes significantly to the pathogenesis of diabetic nephropathy. Although AMP-activated protein kinase (AMPK has been found to inhibit extracellular matrix synthesis by experiments in vivo and vitro, its role in alleviating the deposition of extracellular matrix in renal interstitial fibroblasts has not been well defined. Methods: Currently, we conducted this study to investigate the effects of AMPK on high glucose-induced extracellular matrix synthesis and involved intracellular signaling pathway by using western blot in the kidney fibroblast cell line (NRK-49f. Results: Collagen IV protein levels were significantly increased by high glucose in a time-dependent manner. This was associated with a decrease in Thr72 phosphorylation of AMPK and an increase in phosphorylation of mTOR on Ser2448. High glucose-induced extracellular matrix accumulation and mTOR activation were significantly inhibited by the co-treatment of rAAV-AMPKα1312 (encoding constitutively active AMPKα1 whereas activated by r-AAV-AMPKα1D157A (encoding dominant negative AMPKα1. In cultured renal fibroblasts, overexpression of AMPKα1D157A upregulated mTOR signaling and matrix synthesis, which were ameliorated by co-treatment with the inhibitor of mTOR, rapamycin. Conclusion: Collectively, these findings indicate that AMPK exerts renoprotective effects by inhibiting the accumulation of extracellular matrix through mTOR signaling pathway.

  12. Rapamycin targeting mTOR and hedgehog signaling pathways blocks human rhabdomyosarcoma growth in xenograft murine model

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    Kaylani, Samer Z. [Division of Hematology and Oncology, Department of Pediatrics, University of Alabama at Birmingham, 1600 7th Avenue South, ACC 414, Birmingham, AL 35233 (United States); Xu, Jianmin; Srivastava, Ritesh K. [Department of Dermatology and Skin Diseases Research Center, University of Alabama at Birmingham, 1530 3rd Avenue South, VH 509, Birmingham, AL 35294-0019 (United States); Kopelovich, Levy [Division of Cancer Prevention, National Cancer Institute, Bethesda (United States); Pressey, Joseph G. [Division of Hematology and Oncology, Department of Pediatrics, University of Alabama at Birmingham, 1600 7th Avenue South, ACC 414, Birmingham, AL 35233 (United States); Athar, Mohammad, E-mail: mathar@uab.edu [Department of Dermatology and Skin Diseases Research Center, University of Alabama at Birmingham, 1530 3rd Avenue South, VH 509, Birmingham, AL 35294-0019 (United States)

    2013-06-14

    Graphical abstract: Intervention of poorly differentiated RMS by rapamycin: In poorly differentiated RMS, rapamycin blocks mTOR and Hh signaling pathways concomitantly. This leads to dampening in cell cycle regulation and induction of apoptosis. This study provides a rationale for the therapeutic intervention of poorly differentiated RMS by treating patients with rapamycin alone or in combination with other chemotherapeutic agents. -- Highlights: •Rapamycin abrogates RMS tumor growth by modulating proliferation and apoptosis. •Co-targeting mTOR/Hh pathways underlie the molecular basis of effectiveness. •Reduction in mTOR/Hh pathways diminish EMT leading to reduced invasiveness. -- Abstract: Rhabdomyosarcomas (RMS) represent the most common childhood soft-tissue sarcoma. Over the past few decades outcomes for low and intermediate risk RMS patients have slowly improved while patients with metastatic or relapsed RMS still face a grim prognosis. New chemotherapeutic agents or combinations of chemotherapies have largely failed to improve the outcome. Based on the identification of novel molecular targets, potential therapeutic approaches in RMS may offer a decreased reliance on conventional chemotherapy. Thus, identification of effective therapeutic agents that specifically target relevant pathways may be particularly beneficial for patients with metastatic and refractory RMS. The PI3K/AKT/mTOR pathway has been found to be a potentially attractive target in RMS therapy. In this study, we provide evidence that rapamycin (sirolimus) abrogates growth of RMS development in a RMS xenograft mouse model. As compared to a vehicle-treated control group, more than 95% inhibition in tumor growth was observed in mice receiving parenteral administration of rapamycin. The residual tumors in rapamycin-treated group showed significant reduction in the expression of biomarkers indicative of proliferation and tumor invasiveness. These tumors also showed enhanced apoptosis

  13. Dietary protein sources differentially affect microbiota, mTOR activity and transcription of mTOR signaling pathways in the small intestine.

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    Soumya K Kar

    Full Text Available Dietary protein sources can have profound effects on host-microbe interactions in the gut that are critically important for immune resilience. However more knowledge is needed to assess the impact of different protein sources on gut and animal health. Thirty-six wildtype male C57BL/6J mice of 35 d age (n = 6/group; mean ± SEM body weight 21.9 ± 0.25 g were randomly assigned to groups fed for four weeks with semi synthetic diets prepared with one of the following protein sources containing (300 g/kg as fed basis: soybean meal (SBM, casein, partially delactosed whey powder, spray dried plasma protein, wheat gluten meal and yellow meal worm. At the end of the experiment, mice were sacrificed to collect ileal tissue to acquire gene expression data, and mammalian (mechanistic target of rapamycin (mTOR activity, ileal digesta to study changes in microbiota and serum to measure cytokines and chemokines. By genome-wide transcriptome analysis, we identified fourteen high level regulatory genes that are strongly affected in SBM-fed mice compared to the other experimental groups. They mostly related to the mTOR pathway. In addition, an increased (P < 0.05 concentration of granulocyte colony-stimulating factor was observed in serum of SBM-fed mice compared to other dietary groups. Moreover, by 16S rRNA sequencing, we observed that SBM-fed mice had higher (P < 0.05 abundances of Bacteroidales family S24-7, compared to the other dietary groups. We showed that measurements of genome-wide expression and microbiota composition in the mouse ileum reveal divergent responses to diets containing different protein sources, in particular for a diet based on SBM.

  14. Enhancement of Autophagy by Simvastatin through Inhibition of Rac1-mTOR Signaling Pathway in Coronary Arterial Myocytes

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    Yu-Miao Wei

    2013-06-01

    Full Text Available Background/Aims: In addition to their action of lowering blood cholesterol levels, statins modulate biological characteristics and functions of arterial myocytes such as viability, proliferation, apoptosis, survival and contraction. The present study tested whether simvastatin, as a prototype statin, enhances autophagy in coronary arterial myocytes (CAMs to thereby exert their beneficial effects in atherosclerosis. Methods and Results: Using flow cytometry, we demonstrated that simvastatin significantly increased the autophagsome formation in CAMs. Western blot analysis confirmed that simvastatin significantly increased protein expression of typical autophagy markers LC3B and Beclin1 in these CAMs. Confocal microscopy further demonstrated that simvastatin increased fusion of autophagosomes with lysosomes, which was blocked by autophagy inhibitor 3-methyladenine or silencing of Atg7 genes. Simvastatin reduced mammalian target of rapamycin (mTOR activity, which was reversed by Rac1-GTPase overexpression and the mTOR agonist phosphatidic acid. Moreover, both Rac1-GTPase overexpression and activation of mTOR by phosphatidic acid drastically blocked simvastatin-induced autophagosome formation in CAMs. Interestingly, simvastatin increased protein expression of a contractile phenotype marker calponin in CAMs, which was blocked by autophagy inhibitor 3-methyladenine. Simvastatin markedly reduced proliferation of CAMs under both control and proatherogenic stimulation. However, this inhibitory effect of simvastatin on CAM proliferation was blocked by by autophagy inhibitor 3-methyladenine or silencing of Atg7 genes. Lastly, animal experiments demonstrated that simvastatin increased protein expression of LC3B and calponin in mouse coronary arteries. Conclusion: Our results indicate that simvastatin inhibits the Rac1-mTOR pathway and thereby increases autophagy in CAMs which may stabilize CAMs in the contractile phenotype to prevent proliferation and growth

  15. Selective regulation of YB-1 mRNA translation by the mTOR signaling pathway is not mediated by 4E-binding protein.

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    Lyabin, D N; Ovchinnikov, L P

    2016-03-02

    The Y-box binding protein 1 (YB-1) is a key regulator of gene expression at the level of both translation and transcription. The mode of its action on cellular events depends on its subcellular distribution and the amount in the cell. So far, the regulatory mechanisms of YB-1 synthesis have not been adequately studied. Our previous finding was that selective inhibition of YB-1 mRNA translation was caused by suppression of activity of the mTOR signaling pathway. It was suggested that this event may be mediated by phosphorylation of the 4E-binding protein (4E-BP). Here, we report that 4E-BP alone can only slightly inhibit YB-1 synthesis both in the cell and in vitro, although it essentially decreases binding of the 4F-group translation initiation factors to mRNA. With inhibited mTOR kinase, the level of mRNA binding to the eIF4F-group factors was decreased, while that to 4E-BP1 was increased, as was observed for both mTOR kinase-sensitive mRNAs and those showing low sensitivity. This suggests that selective inhibition of translation of YB-1 mRNA, and probably some other mRNAs as well, by mTOR kinase inhibitors is not mediated by the action of the 4E-binding protein upon functions of the 4F-group translation initiation factors.

  16. Effects of dietary poly-β-hydroxybutyrate (PHB) on microbiota composition and the mTOR signaling pathway in the intestines of litopenaeus vannamei.

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    Duan, Yafei; Zhang, Yue; Dong, Hongbiao; Wang, Yun; Zhang, Jiasong

    2017-12-01

    Poly-β-hydroxybutyrate (PHB) is a natural polymer of the short chain fatty acid β-hydroxybutyrate, which acts as a microbial control agent. The mammalian target of the rapamycin (mTOR) signaling pathway plays a crucial role in intestine inflammation and epithelial morphogenesis. In this study, we examined the composition of intestine microbiota, and mTOR signaling-related gene expression in Pacific white shrimp Litopenaeus vannamei fed diets containing different levels of PHB: 0% (Control), 1% (PHB1), 3% (PHB3), and 5% (PHB5) (w/w) for 35 days. High-throughput sequencing analysis revealed that dietary PHB altered the composition and diversity of intestine microbiota, and that the microbiota diversity decreased with the increasing doses of PHB. Specifically, dietary PHB increased the relative abundance of Proteobacteria and Tenericutes in the PHB1 and PHB5 groups, respectively, and increased that of Gammaproteobacteria in the three PHB groups. Alternatively, PHB decreased Alphaproteobacteria in the PHB3 and PHB5 groups. At the genus level, dietary PHB increased the abundance of beneficial bacteria, such as Bacillus, Lactobacillus, Lactococcus, Clostridium, and Bdellovibrio. The relative mRNA expression levels of the mTOR signaling-related genes TOR, 4E-BP, eIF4E1α, and eIF4E2 all increased in the three PHB treatment groups. These results revealed that dietary PHB supplementation had a beneficial effect on intestine health of L. vannamei by modulating the composition of intestine microbiota and activating mTOR signaling.

  17. Exercise and dietary change ameliorate high fat diet induced obesity and insulin resistance via mTOR signaling pathway.

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    Bae, Ju Yong; Shin, Ki Ok; Woo, Jinhee; Woo, Sang Heon; Jang, Ki Soeng; Lee, Yul Hyo; Kang, Sunghwun

    2016-06-01

    The purpose of this study was to investigate the effect of exercise and dietary change on obesity and insulin resistance and mTOR signaling protein levels in skeletal muscles of obese rats. Sixty male Sprague-Dawley rats were divided into CO (Normal diet) and HF (High Fat diet) groups in order to induce obesity for 15 weeks. The rats were then subdivided into CO, COT (CO + Training), HF, HFT (HF + Training), HFND (Dietary change), and HFNDT (HFND + Training) groups (10 rats / group). The training groups underwent moderate-intensity treadmill exercise for 8 weeks, after which soleus muscles were excised and analyzed. Data was statistically analyzed by independent t-test and One-way ANOVA tests with a 0.05 significance level. Fasting blood glucose, plasma insulin, and HOMA-IR in the HF group were significantly higher, as compared with other groups (p continuous high fat intake, regular exercise and dietary change showed a positive effect on insulin resistance and mTOR signaling protein levels.

  18. mTOR Signaling Confers Resistance to Targeted Cancer Drugs.

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    Guri, Yakir; Hall, Michael N

    2016-11-01

    Cancer is a complex disease and a leading cause of death worldwide. Extensive research over decades has led to the development of therapies that target cancer-specific signaling pathways. However, the clinical benefits of such drugs are at best transient due to tumors displaying intrinsic or adaptive resistance. The underlying compensatory pathways that allow cancer cells to circumvent a drug blockade are poorly understood. We review here recent studies suggesting that mammalian TOR (mTOR) signaling is a major compensatory pathway conferring resistance to many cancer drugs. mTOR-mediated resistance can be cell-autonomous or non-cell-autonomous. These findings suggest that mTOR signaling should be monitored routinely in tumors and that an mTOR inhibitor should be considered as a co-therapy. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Artemisinic acid exhibits antitumor activity in MCF-7 breast cancer cells through the inhibition of angiogenesis, VEGF, m-TOR and AKT signalling pathways

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    Yan Cui

    2016-09-01

    Full Text Available The aim of the present study was to evaluate the antitumor and anti-angiogenic effects of artemisinic acid in MCF-7 human breast cancer cells. Various cell signalling pathways (VEGF, m-TOR and AKT signalling pathways and MTT assay were used. The in vivo antitumor activity of artemisinic acid was evaluated by means of tumor xenograft mouse model. Transwell cell migration assay was used to examine the chemotactic motility of the human umbilical vascular endothelial cells (HUVECs, while as endothelial cell capillary-like tube formation assay was used to evaluate the effect of artemisinic acid on the tube formation in HUVECs. We found that artemisinic acid considerably reduced both the volume and weight of concrete tumors and reduced angiogenesis in a xenograft mouse tumor model in vivo. Further, artemisinic acid suppressed the VEGF-induced cell migration and capillary-like tube formation of HUVECs in a dose-dependent manner. Artemisinic acid was found to suppress the VEGF-induced phosphorylation of VEGFR2 and also the activity of AKT and m-TOR.

  20. DNA damage-inducible transcript 4 (DDIT4) mediates methamphetamine-induced autophagy and apoptosis through mTOR signaling pathway in cardiomyocytes

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    Chen, Rui; Wang, Bin; Chen, Ling; Cai, Dunpeng; Li, Bing; Chen, Chuanxiang; Huang, Enping; Liu, Chao; Lin, Zhoumeng; Xie, Wei-Bing; Wang, Huijun

    2016-01-01

    Methamphetamine (METH) is an amphetamine-like psychostimulant that is commonly abused. Previous studies have shown that METH can induce damages to the nervous system and recent studies suggest that METH can also cause adverse and potentially lethal effects on the cardiovascular system. Recently, we demonstrated that DNA damage-inducible transcript 4 (DDIT4) regulates METH-induced neurotoxicity. However, the role of DDIT4 in METH-induced cardiotoxicity remains unknown. We hypothesized that DDIT4 may mediate METH-induced autophagy and apoptosis in cardiomyocytes. To test the hypothesis, we examined DDIT4 protein expression in cardiomyocytes and in heart tissues of rats exposed to METH with Western blotting. We also determined the effects on METH-induced autophagy and apoptosis after silencing DDIT4 expression with synthetic siRNA with or without pretreatment of a mTOR inhibitor rapamycin in cardiomyocytes using Western blot analysis, fluorescence microscopy and TUNEL staining. Our results showed that METH exposure increased DDIT4 expression and decreased phosphorylation of mTOR that was accompanied with increased autophagy and apoptosis both in vitro and in vivo. These effects were normalized after silencing DDIT4. On the other hand, rapamycin promoted METH-induced autophagy and apoptosis in DDIT4 knockdown cardiomyocytes. These results suggest that DDIT4 mediates METH-induced autophagy and apoptosis through mTOR signaling pathway in cardiomyocytes. - Highlights: • METH exposure increases DDIT4 expression in cardiomyocytes. • DDIT4 mediates METH-induced autophagy and apoptosis in cardiomyocytes. • DDIT4 silencing protects cardiomyocytes against METH-caused autophagy and apoptosis.

  1. DNA damage-inducible transcript 4 (DDIT4) mediates methamphetamine-induced autophagy and apoptosis through mTOR signaling pathway in cardiomyocytes

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    Chen, Rui [Department of Forensic Medicine, School of Basic Medical Science, Southern Medical University, Guangzhou 510515 (China); Department of Forensic Medicine, Guangdong Medical University, Dongguan 523808 (China); Wang, Bin; Chen, Ling; Cai, Dunpeng; Li, Bing; Chen, Chuanxiang; Huang, Enping [Department of Forensic Medicine, School of Basic Medical Science, Southern Medical University, Guangzhou 510515 (China); Liu, Chao [Guangzhou Forensic Science Institute, Guangzhou 510030 (China); Lin, Zhoumeng [Institute of Computational Comparative Medicine and Department of Anatomy and Physiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506 (United States); Xie, Wei-Bing, E-mail: xieweib@126.com [Department of Forensic Medicine, School of Basic Medical Science, Southern Medical University, Guangzhou 510515 (China); Wang, Huijun, E-mail: hjwang711@yahoo.cn [Department of Forensic Medicine, School of Basic Medical Science, Southern Medical University, Guangzhou 510515 (China)

    2016-03-15

    Methamphetamine (METH) is an amphetamine-like psychostimulant that is commonly abused. Previous studies have shown that METH can induce damages to the nervous system and recent studies suggest that METH can also cause adverse and potentially lethal effects on the cardiovascular system. Recently, we demonstrated that DNA damage-inducible transcript 4 (DDIT4) regulates METH-induced neurotoxicity. However, the role of DDIT4 in METH-induced cardiotoxicity remains unknown. We hypothesized that DDIT4 may mediate METH-induced autophagy and apoptosis in cardiomyocytes. To test the hypothesis, we examined DDIT4 protein expression in cardiomyocytes and in heart tissues of rats exposed to METH with Western blotting. We also determined the effects on METH-induced autophagy and apoptosis after silencing DDIT4 expression with synthetic siRNA with or without pretreatment of a mTOR inhibitor rapamycin in cardiomyocytes using Western blot analysis, fluorescence microscopy and TUNEL staining. Our results showed that METH exposure increased DDIT4 expression and decreased phosphorylation of mTOR that was accompanied with increased autophagy and apoptosis both in vitro and in vivo. These effects were normalized after silencing DDIT4. On the other hand, rapamycin promoted METH-induced autophagy and apoptosis in DDIT4 knockdown cardiomyocytes. These results suggest that DDIT4 mediates METH-induced autophagy and apoptosis through mTOR signaling pathway in cardiomyocytes. - Highlights: • METH exposure increases DDIT4 expression in cardiomyocytes. • DDIT4 mediates METH-induced autophagy and apoptosis in cardiomyocytes. • DDIT4 silencing protects cardiomyocytes against METH-caused autophagy and apoptosis.

  2. Vorinostat, an HDAC inhibitor attenuates epidermoid squamous cell carcinoma growth by dampening mTOR signaling pathway in a human xenograft murine model

    Energy Technology Data Exchange (ETDEWEB)

    Kurundkar, Deepali; Srivastava, Ritesh K.; Chaudhary, Sandeep C. [Department of Dermatology and Skin Diseases Research Center, University of Alabama at Birmingham, 1530 3rd Avenue South, VH 509, Birmingham, AL 35294-0019 (United States); Ballestas, Mary E. [Department of Pediatrics Infectious Disease, Children' s of Alabama, School of Medicine, University of Alabama at Birmingham, AL (United States); Kopelovich, Levy [Division of Cancer Prevention, National Cancer Institute, 6130 Executive Blvd., Suite 2114, Bethesda, MD 20892 (United States); Elmets, Craig A. [Department of Dermatology and Skin Diseases Research Center, University of Alabama at Birmingham, 1530 3rd Avenue South, VH 509, Birmingham, AL 35294-0019 (United States); Athar, Mohammad, E-mail: mathar@uab.edu [Department of Dermatology and Skin Diseases Research Center, University of Alabama at Birmingham, 1530 3rd Avenue South, VH 509, Birmingham, AL 35294-0019 (United States)

    2013-01-15

    Histone deacetylase (HDAC) inhibitors are potent anticancer agents and show efficacy against various human neoplasms. Vorinostat is a potent HDAC inhibitor and has shown potential to inhibit growth of human xenograft tumors. However, its effect on the growth of skin neoplasm remains undefined. In this study, we show that vorinostat (2 μM) reduced expression of HDAC1, 2, 3, and 7 in epidermoid carcinoma A431 cells. Consistently, it increased acetylation of histone H3 and p53. Vorinostat (100 mg/kg body weight, IP) treatment reduced human xenograft tumor growth in highly immunosuppressed nu/nu mice. Histologically, the vorinostat-treated tumor showed features of well-differentiation with large necrotic areas. Based on proliferating cell nuclear antigen (PCNA) staining and expression of cyclins D1, D2, E, and A, vorinostat seems to impair proliferation by down-regulating the expression of these proteins. However, it also induced apoptosis. The mechanism by which vorinostat blocks proliferation and makes tumor cells prone to apoptosis, involved inhibition of mTOR signaling which was accompanied by reduction in cell survival AKT and extracellular-signal regulated kinase (ERK) signaling pathways. Our data provide a novel mechanism-based therapeutic intervention for cutaneous squamous cell carcinoma (SCC). Vorinostat may be utilized to cure skin neoplasms in organ transplant recipient (OTR). These patients have high morbidity and surgical removal of these lesions which frequently develop in these patients, is difficult. -- Highlights: ► Vorinostat reduces SCC growth in a xenograft murine model. ► Vorinostat dampens proliferation and induces apoptosis in tumor cells. ► Diminution in mTOR, Akt and ERK signaling underlies inhibition in proliferation. ► Vorinostat by inhibiting HDACs inhibits epithelial–mesenchymal transition.

  3. Vorinostat, an HDAC inhibitor attenuates epidermoid squamous cell carcinoma growth by dampening mTOR signaling pathway in a human xenograft murine model

    International Nuclear Information System (INIS)

    Kurundkar, Deepali; Srivastava, Ritesh K.; Chaudhary, Sandeep C.; Ballestas, Mary E.; Kopelovich, Levy; Elmets, Craig A.; Athar, Mohammad

    2013-01-01

    Histone deacetylase (HDAC) inhibitors are potent anticancer agents and show efficacy against various human neoplasms. Vorinostat is a potent HDAC inhibitor and has shown potential to inhibit growth of human xenograft tumors. However, its effect on the growth of skin neoplasm remains undefined. In this study, we show that vorinostat (2 μM) reduced expression of HDAC1, 2, 3, and 7 in epidermoid carcinoma A431 cells. Consistently, it increased acetylation of histone H3 and p53. Vorinostat (100 mg/kg body weight, IP) treatment reduced human xenograft tumor growth in highly immunosuppressed nu/nu mice. Histologically, the vorinostat-treated tumor showed features of well-differentiation with large necrotic areas. Based on proliferating cell nuclear antigen (PCNA) staining and expression of cyclins D1, D2, E, and A, vorinostat seems to impair proliferation by down-regulating the expression of these proteins. However, it also induced apoptosis. The mechanism by which vorinostat blocks proliferation and makes tumor cells prone to apoptosis, involved inhibition of mTOR signaling which was accompanied by reduction in cell survival AKT and extracellular-signal regulated kinase (ERK) signaling pathways. Our data provide a novel mechanism-based therapeutic intervention for cutaneous squamous cell carcinoma (SCC). Vorinostat may be utilized to cure skin neoplasms in organ transplant recipient (OTR). These patients have high morbidity and surgical removal of these lesions which frequently develop in these patients, is difficult. -- Highlights: ► Vorinostat reduces SCC growth in a xenograft murine model. ► Vorinostat dampens proliferation and induces apoptosis in tumor cells. ► Diminution in mTOR, Akt and ERK signaling underlies inhibition in proliferation. ► Vorinostat by inhibiting HDACs inhibits epithelial–mesenchymal transition.

  4. Finding a better drug for epilepsy: the mTOR pathway as an antiepileptogenic target.

    NARCIS (Netherlands)

    Galanopoulou, A.S.; Gorter, J.A.; Cepeda, C.

    2012-01-01

    The mammalian target of rapamycin (mTOR) signaling pathway regulates cell growth, differentiation, proliferation, and metabolism. Loss-of-function mutations in upstream regulators of mTOR have been highly associated with dysplasias, epilepsy, and neurodevelopmental disorders. These include tuberous

  5. Vorinostat, an HDAC inhibitor attenuates epidermoid squamous cell carcinoma growth by dampening mTOR signaling pathway in a human xenograft murine model.

    Science.gov (United States)

    Kurundkar, Deepali; Srivastava, Ritesh K; Chaudhary, Sandeep C; Ballestas, Mary E; Kopelovich, Levy; Elmets, Craig A; Athar, Mohammad

    2013-01-15

    Histone deacetylase (HDAC) inhibitors are potent anticancer agents and show efficacy against various human neoplasms. Vorinostat is a potent HDAC inhibitor and has shown potential to inhibit growth of human xenograft tumors. However, its effect on the growth of skin neoplasm remains undefined. In this study, we show that vorinostat (2 μM) reduced expression of HDAC1, 2, 3, and 7 in epidermoid carcinoma A431 cells. Consistently, it increased acetylation of histone H3 and p53. Vorinostat (100mg/kg body weight, IP) treatment reduced human xenograft tumor growth in highly immunosuppressed nu/nu mice. Histologically, the vorinostat-treated tumor showed features of well-differentiation with large necrotic areas. Based on proliferating cell nuclear antigen (PCNA) staining and expression of cyclins D1, D2, E, and A, vorinostat seems to impair proliferation by down-regulating the expression of these proteins. However, it also induced apoptosis. The mechanism by which vorinostat blocks proliferation and makes tumor cells prone to apoptosis, involved inhibition of mTOR signaling which was accompanied by reduction in cell survival AKT and extracellular-signal regulated kinase (ERK) signaling pathways. Our data provide a novel mechanism-based therapeutic intervention for cutaneous squamous cell carcinoma (SCC). Vorinostat may be utilized to cure skin neoplasms in organ transplant recipient (OTR). These patients have high morbidity and surgical removal of these lesions which frequently develop in these patients, is difficult. Copyright © 2012 Elsevier Inc. All rights reserved.

  6. Glutamate alleviates muscle protein loss by modulating TLR4, NODs, Akt/FOXO and mTOR signaling pathways in LPS-challenged piglets.

    Directory of Open Access Journals (Sweden)

    Ping Kang

    Full Text Available The experiment was conducted to study the effect of the glutamate (Glu on muscle protein loss through toll-like receptor 4 (TLR4, nucleotide-binding oligomerization domain proteins (NODs, Akt/Forkhead Box O (Akt/FOXO and mammalian target of rapamycin (mTOR signaling pathways in LPS-challenged piglets. Twenty-four weaned piglets were assigned into four treatments: (1 Control; (2 LPS+0% Glu; (3 LPS + 1.0% Glu; (4 LPS + 2.0% Glu. The experiment was lasted for 28 days. On d 28, the piglets in the LPS challenged groups were injected with LPS on 100 μg/kg body weight (BW, and the piglets in the control group were injected with the same volume of 0.9% NaCl solution. After 4 h LPS or saline injection, the piglets were slaughtered and the muscle samples were collected. Glu supplementation increased the protein/DNA ratio in gastrocnemius muscle, and the protein content in longissimus dorsi (LD muscle after LPS challenge (P<0.05. In addition, Glu supplementation decreased TLR4, IL-1 receptor-associated kinase (IRAK 1, receptor-interacting serine/threonine-protein kinase (RIPK 2, and nuclear factor-κB (NF-κB mRNA expression in gastrocnemius muscle (P<0.05, MyD88 mRNA expression in LD muscle, and FOXO1 mRNA expression in LD muscle (P<0.05. Moreover, Glu supplementation increased p-Akt/t-Akt ratio (P<0.05 in gastrocnemius muscle, and p-4EBP1/t-4EBP1 ratio in both gastrocnemius and LD muscles (P<0.05. Glu supplementation in the piglets' diets might be an effective strategy to alleviate LPS-induced muscle protein loss, which might be due to suppressing the mRNA expression of TLR4 and NODs signaling-related genes, and modulating Akt/FOXO and mTOR signaling pathways.

  7. Involvement of TSC genes and differential expression of other members of the mTOR signaling pathway in oral squamous cell carcinoma

    International Nuclear Information System (INIS)

    Chakraborty, Sanjukta; Mohiyuddin, SM Azeem; Gopinath, KS; Kumar, Arun

    2008-01-01

    Despite extensive research, the five-year survival rate of oral squamous cell carcinoma (OSCC) patients has not improved. Effective treatment of OSCC requires the identification of molecular targets and signaling pathways to design appropriate therapeutic strategies. Several genes from the mTOR signaling pathway are known to be dysregulated in a wide spectrum of cancers. However, not much is known about the involvement of this pathway in tumorigenesis of OSCC. We therefore investigated the role of the tumor suppressor genes, TSC1 and TSC2, and other members of this pathway in tumorigenesis of OSCC. Expression of genes at the RNA and protein levels was examined by semi-quantitative RT-PCR and western blot analyses, respectively. Loss of heterozygosity was studied using matched blood and tumor DNA samples and microsatellite markers from the TSC1, TSC2 and PTEN candidate regions. The effect of promoter methylation on TSC gene expression was studied by treating cells with methyltransferase inhibitor 5-azacytidine. Methylation status of the TSC2 promoter in tissue samples was examined by combined bisulfite restriction analysis (COBRA). The semi-quantitative RT-PCR analysis showed downregulation of TSC1, TSC2, EIF4EBP1 and PTEN, and upregulation of PIK3C2A, AKT1, PDPK1, RHEB, FRAP1, RPS6KB1, EIF4E and RPS6 in tumors. A similar observation was made for AKT1 and RPS6KB1 expression in tumors at the protein level. Investigation of the mechanism of downregulation of TSC genes identified LOH in 36.96% and 39.13% of the tumors at the TSC1 and TSC2 loci, respectively. No mutation was found in TSC genes. A low LOH rate of 13% was observed at the PTEN locus. Treatment of an OSCC cell line with the methyltransferase inhibitor 5-azacytidine showed a significant increase in the expression of TSC genes, suggesting methylation of their promoters. However, the 5-azacytidine treatment of non-OSCC HeLa cells showed a significant increase in the expression of the TSC2 gene only. In order

  8. Allomyrina Dichotoma Larvae Regulate Food Intake and Body Weight in High Fat Diet-Induced Obese Mice Through mTOR and Mapk Signaling Pathways

    Directory of Open Access Journals (Sweden)

    Jongwan Kim

    2016-02-01

    Full Text Available Recent evidence has suggested that the Korean horn beetle (Allomyrina dichotoma has anti-hepatofibrotic, anti-neoplastic, and antibiotic effects and is recognized as a traditional medicine. In our previous works, Allomyrina dichotoma larvae (ADL inhibited differentiation of adipocytes both in vitro and in vivo. However, the anorexigenic and endoplasmic reticulum(ER stress-reducing effects of ADL in obesity has not been examined. In this study, we investigated the anorexigenic and ER stress-reducing effects of ADL in the hypothalamus of diet-induced obese (DIO mice. Intracerebroventricular (ICV administration of ethanol extract of ADL (ADE suggested that an antagonizing effect on ghrelin-induced feeding behavior through the mTOR and MAPK signaling pathways. Especially, ADE resulted in strong reduction of ER stress both in vitro and in vivo. These findings strongly suggest that ADE and its constituent bioactive compounds are available and valuable to use for treatment of various diseases driven by prolonged ER stress.

  9. Hypothalamic mTOR signaling regulates food intake.

    Science.gov (United States)

    Cota, Daniela; Proulx, Karine; Smith, Kathi A Blake; Kozma, Sara C; Thomas, George; Woods, Stephen C; Seeley, Randy J

    2006-05-12

    The mammalian Target of Rapamycin (mTOR) protein is a serine-threonine kinase that regulates cell-cycle progression and growth by sensing changes in energy status. We demonstrated that mTOR signaling plays a role in the brain mechanisms that respond to nutrient availability, regulating energy balance. In the rat, mTOR signaling is controlled by energy status in specific regions of the hypothalamus and colocalizes with neuropeptide Y and proopiomelanocortin neurons in the arcuate nucleus. Central administration of leucine increases hypothalamic mTOR signaling and decreases food intake and body weight. The hormone leptin increases hypothalamic mTOR activity, and the inhibition of mTOR signaling blunts leptin's anorectic effect. Thus, mTOR is a cellular fuel sensor whose hypothalamic activity is directly tied to the regulation of energy intake.

  10. The progesterone-induced enhancement of object recognition memory consolidation involves activation of the extracellular signal-regulated kinase (ERK) and mammalian target of rapamycin (mTOR) pathways in the dorsal hippocampus

    Science.gov (United States)

    Orr, Patrick T.; Rubin, Amanda J.; Fan, Lu; Kent, Brianne A.; Frick, Karyn M.

    2012-01-01

    Although much recent work has elucidated the biochemical mechanisms underlying the modulation of memory by 17β-estradiol, little is known about the signaling events through which progesterone (P) regulates memory. We recently demonstrated that immediate post-training infusion of P into the dorsal hippocampus enhances object recognition memory consolidation in young ovariectomized female mice (Orr et al., 2009). The goal of the present study was to identify the biochemical alterations that might underlie this mnemonic enhancement. We hypothesized that the P-induced enhancement of object recognition would be dependent on activation of the ERK and mTOR pathways. In young ovariectomized mice, we found that bilateral dorsal hippocampal infusion of P significantly increased levels of phospho-p42 ERK and the mTOR substrate S6K in the dorsal hippocampus 5 minutes after infusion. Phospho-p42 ERK levels were downregulated 15 minutes after infusion and returned to baseline 30 minutes after infusion, suggesting a biphasic effect of P on ERK activation. Dorsal hippocampal ERK and mTOR activation were necessary for P to facilitate memory consolidation, as suggested by the fact that inhibitors of both pathways infused into the dorsal hippocampus immediately after training blocked the P-induced enhancement of object recognition. Collectively, these data provide the first demonstration that the ability of P to enhance memory consolidation depends on the rapid activation of cell signaling and protein synthesis pathways in the dorsal hippocampus. PMID:22265866

  11. Next-generation mTOR inhibitors in clinical oncology: how pathway complexity informs therapeutic strategy.

    LENUS (Irish Health Repository)

    Wander, Seth A

    2011-04-01

    Mammalian target of rapamycin (mTOR) is a PI3K-related kinase that regulates cell growth, proliferation, and survival via mTOR complex 1 (mTORC1) and mTORC2. The mTOR pathway is often aberrantly activated in cancers. While hypoxia, nutrient deprivation, and DNA damage restrain mTORC1 activity, multiple genetic events constitutively activate mTOR in cancers. Here we provide a brief overview of the signaling pathways up- and downstream of mTORC1 and -2, and discuss the insights into therapeutic anticancer targets - both those that have been tried in the clinic with limited success and those currently under clinical development - that knowledge of these pathways gives us.

  12. Mechanical stimulation induces mTOR signaling via an ERK-independent mechanism: implications for a direct activation of mTOR by phosphatidic acid.

    Directory of Open Access Journals (Sweden)

    Jae Sung You

    Full Text Available Signaling by mTOR is a well-recognized component of the pathway through which mechanical signals regulate protein synthesis and muscle mass. However, the mechanisms involved in the mechanical regulation of mTOR signaling have not been defined. Nevertheless, recent studies suggest that a mechanically-induced increase in phosphatidic acid (PA may be involved. There is also evidence which suggests that mechanical stimuli, and PA, utilize ERK to induce mTOR signaling. Hence, we reasoned that a mechanically-induced increase in PA might promote mTOR signaling via an ERK-dependent mechanism. To test this, we subjected mouse skeletal muscles to mechanical stimulation in the presence or absence of a MEK/ERK inhibitor, and then measured several commonly used markers of mTOR signaling. Transgenic mice expressing a rapamycin-resistant mutant of mTOR were also used to confirm the validity of these markers. The results demonstrated that mechanically-induced increases in p70(s6k T389 and 4E-BP1 S64 phosphorylation, and unexpectedly, a loss in total 4E-BP1, were fully mTOR-dependent signaling events. Furthermore, we determined that mechanical stimulation induced these mTOR-dependent events, and protein synthesis, through an ERK-independent mechanism. Similar to mechanical stimulation, exogenous PA also induced mTOR-dependent signaling via an ERK-independent mechanism. Moreover, PA was able to directly activate mTOR signaling in vitro. Combined, these results demonstrate that mechanical stimulation induces mTOR signaling, and protein synthesis, via an ERK-independent mechanism that potentially involves a direct interaction of PA with mTOR. Furthermore, it appears that a decrease in total 4E-BP1 may be part of the mTOR-dependent mechanism through which mechanical stimuli activate protein synthesis.

  13. Regulation of autophagy by amino acids and MTOR-dependent signal transduction

    NARCIS (Netherlands)

    Meijer, Alfred J.; Lorin, Séverine; Blommaart, Edward F.; Codogno, Patrice

    2015-01-01

    Amino acids not only participate in intermediary metabolism but also stimulate insulin-mechanistic target of rapamycin (MTOR)-mediated signal transduction which controls the major metabolic pathways. Among these is the pathway of autophagy which takes care of the degradation of long-lived proteins

  14. Hypothalamic mTOR pathway mediates thyroid hormone-induced hyperphagia in hyperthyroidism.

    Science.gov (United States)

    Varela, Luis; Martínez-Sánchez, Noelia; Gallego, Rosalía; Vázquez, María J; Roa, Juan; Gándara, Marina; Schoenmakers, Erik; Nogueiras, Rubén; Chatterjee, Krishna; Tena-Sempere, Manuel; Diéguez, Carlos; López, Miguel

    2012-06-01

    Hyperthyroidism is characterized in rats by increased energy expenditure and marked hyperphagia. Alterations of thermogenesis linked to hyperthyroidism are associated with dysregulation of hypothalamic AMPK and fatty acid metabolism; however, the central mechanisms mediating hyperthyroidism-induced hyperphagia remain largely unclear. Here, we demonstrate that hyperthyroid rats exhibit marked up-regulation of the hypothalamic mammalian target of rapamycin (mTOR) signalling pathway associated with increased mRNA levels of agouti-related protein (AgRP) and neuropeptide Y (NPY), and decreased mRNA levels of pro-opiomelanocortin (POMC) in the arcuate nucleus of the hypothalamus (ARC), an area where mTOR co-localizes with thyroid hormone receptor-α (TRα). Central administration of thyroid hormone (T3) or genetic activation of thyroid hormone signalling in the ARC recapitulated hyperthyroidism effects on feeding and the mTOR pathway. In turn, central inhibition of mTOR signalling with rapamycin in hyperthyroid rats reversed hyperphagia and normalized the expression of ARC-derived neuropeptides, resulting in substantial body weight loss. The data indicate that in the hyperthyroid state, increased feeding is associated with thyroid hormone-induced up-regulation of mTOR signalling. Furthermore, our findings that different neuronal modulations influence food intake and energy expenditure in hyperthyroidism pave the way for a more rational design of specific and selective therapeutic compounds aimed at reversing the metabolic consequences of this disease. Copyright © 2012 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

  15. Regulation of autophagy by amino acids and MTOR-dependent signal transduction.

    Science.gov (United States)

    Meijer, Alfred J; Lorin, Séverine; Blommaart, Edward F; Codogno, Patrice

    2015-10-01

    Amino acids not only participate in intermediary metabolism but also stimulate insulin-mechanistic target of rapamycin (MTOR)-mediated signal transduction which controls the major metabolic pathways. Among these is the pathway of autophagy which takes care of the degradation of long-lived proteins and of the elimination of damaged or functionally redundant organelles. Proper functioning of this process is essential for cell survival. Dysregulation of autophagy has been implicated in the etiology of several pathologies. The history of the studies on the interrelationship between amino acids, MTOR signaling and autophagy is the subject of this review. The mechanisms responsible for the stimulation of MTOR-mediated signaling, and the inhibition of autophagy, by amino acids have been studied intensively in the past but are still not completely clarified. Recent developments in this field are discussed.

  16. PRAS40 is an integral regulatory component of erythropoietin mTOR signaling and cytoprotection.

    Directory of Open Access Journals (Sweden)

    Zhao Zhong Chong

    Full Text Available Emerging strategies that center upon the mammalian target of rapamycin (mTOR signaling for neurodegenerative disorders may bring effective treatment for a number of difficult disease entities. Here we show that erythropoietin (EPO, a novel agent for nervous system disorders, prevents apoptotic SH-SY5Y cell injury in an oxidative stress model of oxygen-glucose deprivation through phosphatidylinositol-3-kinase (PI 3-K/protein kinase B (Akt dependent activation of mTOR signaling and phosphorylation of the downstream pathways of p70 ribosomal S6 kinase (p70S6K, eukaryotic initiation factor 4E-binding protein 1 (4EBP1, and proline rich Akt substrate 40 kDa (PRAS40. PRAS40 is an important regulatory component either alone or in conjunction with EPO signal transduction that can determine cell survival through apoptotic caspase 3 activation. EPO and the PI 3-K/Akt pathways control cell survival and mTOR activity through the inhibitory post-translational phosphorylation of PRAS40 that leads to subcellular binding of PRAS40 to the cytoplasmic docking protein 14-3-3. However, modulation and phosphorylation of PRAS40 is independent of other protective pathways of EPO that involve extracellular signal related kinase (ERK 1/2 and signal transducer and activator of transcription (STAT5. Our studies highlight EPO and PRAS40 signaling in the mTOR pathway as potential therapeutic strategies for development against degenerative disorders that lead to cell demise.

  17. Lysophosphatidic acid acyltransferase beta regulates mTOR signaling.

    Directory of Open Access Journals (Sweden)

    Michelle A Blaskovich

    Full Text Available Lysophosphatidic acid acyltransferase (LPAAT-β is a phosphatidic acid (PA generating enzyme that plays an essential role in triglyceride synthesis. However, LPAAT-β is now being studied as an important regulator of cell growth and differentiation and as a potential therapeutic target in cancer since PA is necessary for the activity of key proteins such as Raf, PKC-ζ and mTOR. In this report we determine the effect of LPAAT-β silencing with siRNA in pancreatic adenocarcinoma cell lines. We show for the first time that LPAAT-β knockdown inhibits proliferation and anchorage-independent growth of pancreatic cancer cells. This is associated with inhibition of signaling by mTOR as determined by levels of mTORC1- and mTORC2-specific phosphorylation sites on 4E-BP1, S6K and Akt. Since PA regulates the activity of mTOR by modulating its binding to FKBP38, we explored the possibility that LPAAT-β might regulate mTOR by affecting its association with FKBP38. Coimmunoprecipitation studies of FKBP38 with mTOR show increased levels of FKBP38 associated with mTOR when LPAAT-β protein levels are knocked down. Furthermore, depletion of LPAAT-β results in increased Lipin 1 nuclear localization which is associated with increased nuclear eccentricity, a nuclear shape change that is dependent on mTOR, further confirming the ability of LPAAT-β to regulate mTOR function. Our results provide support for the hypothesis that PA generated by LPAAT-β regulates mTOR signaling. We discuss the implications of these findings for using LPAAT-β as a therapeutic target.

  18. Morphoproteomic profiling of the mammalian target of rapamycin (mTOR) signaling pathway in desmoplastic small round cell tumor (EWS/WT1), Ewing's sarcoma (EWS/FLI1) and Wilms' tumor(WT1).

    Science.gov (United States)

    Subbiah, Vivek; Brown, Robert E; Jiang, Yunyun; Buryanek, Jamie; Hayes-Jordan, Andrea; Kurzrock, Razelle; Anderson, Pete M

    2013-01-01

    Desmoplastic small round cell tumor (DSRCT) is a rare sarcoma in adolescents and young adults. The hallmark of this disease is a EWS-WT1 translocation resulting from apposition of the Ewing's sarcoma (EWS) gene with the Wilms' tumor (WT1) gene. We performed morphoproteomic profiling of DSRCT (EWS-WT1), Ewing's sarcoma (EWS-FLI1) and Wilms' tumor (WT1) to better understand the signaling pathways for selecting future targeted therapies. This pilot study assessed patients with DSRCT, Wilms' tumor and Ewing's sarcoma. Morphoproteomics and immunohistochemical probes were applied to detect: p-mTOR (Ser2448); p-Akt (Ser473); p-ERK1/2 (Thr202/Tyr204); p-STAT3 (Tyr 705); and cell cycle-related analytes along with their negative controls. In DSRCT the PI3K/Akt/mTOR pathway is constitutively activated by p-Akt (Ser 473) expression in the nuclear compartment of the tumor cells and p-mTOR phosphorylated on Ser 2448, suggesting mTORC2 (rictor+mTOR) as the dominant form. Ewing's sarcoma had upregulated p-Akt and p-mTOR, predominantly mTORC2. In Wilm's tumor, the mTOR pathway is also activated with most tumor cells moderately expressing p-mTOR (Ser 2448) in plasmalemmal and cytoplasmic compartments. This coincides with the constitutive activation of one of the downstream effectors of the mTORC1 signaling pathway, namely p-p70S6K (Thr 389). There was constitutive activation of the Ras/Raf/ERK pathway p-ERK 1/2 (Thr202/Tyr204) expression in the Wilms tumor and metastatic Ewing's sarcoma, but not in the DSRCT. MORPHOPROTEOMIC TUMOR ANALYSES REVEALED CONSTITUTIVE ACTIVATION OF THE MTOR PATHWAY AS EVIDENCED BY: (a) expression of phosphorylated (p)-mTOR, p-p70S6K; (b) mTORC 2 in EWS and DSRCT; (c) ERK signaling was seen in the advanced setting indicating these as resistance pathways to IGF1R related therapies. This is the first morphoproteomic study of such pathways in these rare malignancies and may have potential therapeutic implications. Further study using morphoproteomic

  19. IL-6 and IGF-1 signaling within and between muscle and bone: how important is the mTOR pathway for bone metabolism?

    NARCIS (Netherlands)

    Bakker, A.D.; Jaspers, R.T.

    2015-01-01

    Insulin-like growth factor 1 (IGF-1) and interleukin 6 (IL-6) play an important role in the adaptation of both muscle and bone to mechanical stimuli. Here, we provide an overview of the functions of IL-6 and IGF-1 in bone and muscle metabolism, and the intracellular signaling pathways that are well

  20. IL-6 and IGF-1 Signaling within, and between, Muscle and Bone: How Important is the mTOR Pathway for Bone Metabolism?

    NARCIS (Netherlands)

    Bakker, A.D.; Jaspers, R.T.

    2015-01-01

    Insulin-like growth factor 1 (IGF-1) and interleukin 6 (IL-6) play an important role in the adaptation of both muscle and bone to mechanical stimuli. Here, we provide an overview of the functions of IL-6 and IGF-1 in bone and muscle metabolism, and the intracellular signaling pathways that are well

  1. Fluoxetine regulates mTOR signalling in a region-dependent manner in depression-like mice

    Science.gov (United States)

    Liu, Xiao-Long; Luo, Liu; Mu, Rong-Hao; Liu, Bin-Bin; Geng, Di; Liu, Qing; Yi, Li-Tao

    2015-01-01

    Previous studies have demonstrated that the mammalian target of rapamycin (mTOR) signaling pathway has an important role in ketamine-induced, rapid antidepressant effects despite the acute administration of fluoxetine not affecting mTOR phosphorylation in the brain. However, the effects of long-term fluoxetine treatment on mTOR modulation have not been assessed to date. In the present study, we examined whether fluoxetine, a type of commonly used antidepressant agent, alters mTOR signaling following chronic administration in different brain regions, including the frontal cortex, hippocampus, amygdala and hypothalamus. We also investigated whether fluoxetine enhanced synaptic protein levels in these regions via the activation of the mTOR signaling pathway and its downstream regulators, p70S6K and 4E-BP-1. The results indicated that chronic fluoxetine treatment attenuated the chronic, unpredictable, mild stress (CUMS)-induced mTOR phosphorylation reduction in the hippocampus and amygdala of mice but not in the frontal cortex or the hypothalamus. Moreover, the CUMS-decreased PSD-95 and synapsin I levels were reversed by fluoxetine, and these effects were blocked by rapamycin only in the hippocampus. In conclusion, our findings suggest that chronic treatment with fluoxetine can induce synaptic protein expression by activating the mTOR signaling pathway in a region-dependent manner and mainly in the hippocampus. PMID:26522512

  2. Finding a better drug for epilepsy: The mTOR pathway as an antiepileptogenic target

    Science.gov (United States)

    Galanopoulou, Aristea S.; Gorter, Jan A.; Cepeda, Carlos

    2012-01-01

    Summary The mTOR signaling pathway regulates cell growth, differentiation, proliferation and metabolism. Loss of function mutations in upstream regulators of mTOR have been highly associated with dysplasias, epilepsy and neurodevelopmental disorders. These include tuberous sclerosis, which is due to mutations in TSC1 or TSC2 genes, mutations in phosphatase and tensin homolog (PTEN) as in Cowden syndrome, polyhydramnios, megalencephaly, symptomatic epilepsy syndrome (PMSE) due to mutations in the STE20-related kinase adaptor alpha (STRADalpha), and neurofibromatosis type 1 attributed to neurofibromin 1 mutations. Inhibition of the mTOR pathway with rapamycin may prevent epilepsy and improve the underlying pathology in mouse models with disrupted mTOR signaling, due to PTEN or TSC mutations. However the timing and duration of its administration appear critical in defining the seizure and pathology-related outcomes. Rapamycin application in human cortical slices from patients with cortical dysplasias reduces the 4-aminopyridine induced oscillations. In the multiple-hit model of infantile spasms, pulse high dose rapamycin administration can reduce the cortical overactivation of the mTOR pathway, suppresses spasms and has disease-modifying effects by partially improving cognitive deficits. In post-status epilepticus models of temporal lobe epilepsy, rapamycin may ameliorate the development of epilepsy-related pathology and reduce the expression of spontaneous seizures, but its effects depend on the timing and duration of administration, and possibly the model used. The observed recurrence of seizures and epilepsy-related pathology after rapamycin discontinuation suggests the need for continuous administration to maintain the benefit. However, the use of pulse administration protocols may be useful in certain age-specific epilepsy syndromes, like infantile spasms, whereas repetitive pulse rapamycin protocols may suffice to sustain a long-term benefit in genetic disorders

  3. Cortisol inhibits mTOR signaling in avascular necrosis of the femoral head.

    Science.gov (United States)

    Liao, Yun; Su, Rui; Zhang, Ping; Yuan, Bo; Li, Ling

    2017-10-18

    ANFH is a major health problem, to which long lasting and definitive treatments are lacking. The aim of this study is to study RNA alterations attributed to cortisol-induced ANFH. Rat models were stratified into three groups: in vitro group (n = 20) for molecular biological assays, control group (n = 3), and ANFH group induced using lipopolysaccharide and dexamethasone (n = 3). Bone marrow-derived endothelial progenitor cells (BM-EPCs) were extracted from the rats. An RNA expression array was performed on BM-EPCs, and enriched genes were subject to pathway analysis. In vitro studies following findings of array results were also performed using the isolated BM-EPCs. Significant alterations in mammalian target of rapamycin (mTOR) and HIF signaling pathways were identified in BM-EPCs of ANFH. By applying cortisol and dexamethasone to BM-EPCs, significant changes in mTOR and HIF elements were identified. The alteration of HIF pathways appeared to be downstream of mTOR signaling. Glucocorticoid receptor (GR) expression was related to glucocorticoid-dependent mRNA expression of mTOR/HIF genes. mTOR-dependent angiogenesis but not anabolism was the target of GR in ANFH. Inhibition of mTOR signaling also induced apoptosis of BM-EPCs via CHOP-dependent DR5 induction in response to GR stimulation. Decreased mTOR signaling in response to GR stimulation leading to downregulated HIF pathway as well as increased apoptosis could be the pathophysiology.

  4. Cross regulation between mTOR signaling and O-GlcNAcylation.

    Science.gov (United States)

    Very, Ninon; Steenackers, Agata; Dubuquoy, Caroline; Vermuse, Jeanne; Dubuquoy, Laurent; Lefebvre, Tony; El Yazidi-Belkoura, Ikram

    2018-06-01

    The hexosamine biosynthetic pathway (HBP) integrates glucose, amino acids, fatty acids and nucleotides metabolisms for uridine diphosphate N-acetylglucosamine (UDP-GlcNAc) synthesis. UDP-GlcNAc is the nucleotide sugar donor for O-linked β-N-acetylglucosaminylation (O-GlcNAcylation) processes. O-GlcNAc transferase (OGT) is the enzyme which transfers the N-acetylglucosamine (O-GlcNAc) residue onto target proteins. Several studies previously showed that glucose metabolism dysregulations associated with obesity, diabetes or cancer correlated with an increase of OGT expression and global O-GlcNAcylation levels. Moreover, these diseases present an increased activation of the nutrient sensing mammalian target of rapamycin (mTOR) pathway. Other works demonstrate that mTOR regulates protein O-GlcNAcylation in cancer cells through stabilization of OGT. In this context, we studied the cross-talk between these two metabolic sensors in vivo in obese mice predisposed to diabetes and in vitro in normal and colon cancer cells. We report that levels of OGT and O-GlcNAcylation are increased in obese mice colon tissues and colon cancer cells and are associated with a higher activation of mTOR signaling. In parallel, treatments with mTOR regulators modulate OGT and O-GlcNAcylation levels in both normal and colon cancer cells. However, deregulation of O-GlcNAcylation affects mTOR signaling activation only in cancer cells. Thus, a crosstalk exists between O-GlcNAcylation and mTOR signaling in contexts of metabolism dysregulation associated to obesity or cancer.

  5. Reactivation of cocaine reward memory engages the Akt/GSK3/mTOR signaling pathway and can be disrupted by GSK3 inhibition.

    Science.gov (United States)

    Shi, Xiangdang; Miller, Jonathan S; Harper, Lauren J; Poole, Rachel L; Gould, Thomas J; Unterwald, Ellen M

    2014-08-01

    Memories return to a labile state following their retrieval and must undergo a process of reconsolidation to be maintained. Thus, disruption of cocaine reward memories by interference with reconsolidation may be therapeutically beneficial in the treatment of cocaine addiction. The objectives were to elucidate the signaling pathway involved in reconsolidation of cocaine reward memory and to test whether targeting this pathway could disrupt cocaine-associated contextual memory. Using a mouse model of conditioned place preference, regulation of the activity of glycogen synthase kinase-3 (GSK3), mammalian target of Rapamycin complex 1 (mTORC1), P70S6K, β-catenin, and the upstream signaling molecule Akt, was studied in cortico-limbic-striatal circuitry after re-exposure to an environment previously paired with cocaine. Levels of phosporylated Akt-Thr308, GSK3α-Ser21, GSK3β-Ser9, mTORC1, and P70S6K were reduced in the nucleus accumbens and hippocampus 10 min after the reactivation of cocaine cue memories. Levels of pAkt and pGSK3 were also reduced in the prefrontal cortex. Since reduced phosphorylation of GSK3 indicates heightened enzyme activity, the effect of a selective GSK3 inhibitor, SB216763, on reconsolidation was tested. Administration of SB216763 immediately after exposure to an environment previously paired with cocaine abrogated a previously established place preference, suggesting that GSK3 inhibition interfered with reconsolidation of cocaine-associated reward memories. These findings suggest that the Akt/GSK3/mTORC1 signaling pathway in the nucleus accumbens, hippocampus, and/or prefrontal cortex is critically involved in the reconsolidation of cocaine contextual reward memory. Inhibition of GSK3 activity during memory retrieval can erase an established cocaine place preference.

  6. mTOR pathway inhibition prevents neuroinflammation and neuronal death in a mouse model of cerebral palsy.

    Science.gov (United States)

    Srivastava, Isha N; Shperdheja, Jona; Baybis, Marianna; Ferguson, Tanya; Crino, Peter B

    2016-01-01

    Mammalian target of rapamycin (mTOR) pathway signaling governs cellular responses to hypoxia and inflammation including induction of autophagy and cell survival. Cerebral palsy (CP) is a neurodevelopmental disorder linked to hypoxic and inflammatory brain injury however, a role for mTOR modulation in CP has not been investigated. We hypothesized that mTOR pathway inhibition would diminish inflammation and prevent neuronal death in a mouse model of CP. Mouse pups (P6) were subjected to hypoxia-ischemia and lipopolysaccharide-induced inflammation (HIL), a model of CP causing neuronal injury within the hippocampus, periventricular white matter, and neocortex. mTOR pathway inhibition was achieved with rapamycin (an mTOR inhibitor; 5mg/kg) or PF-4708671 (an inhibitor of the downstream p70S6kinase, S6K, 75 mg/kg) immediately following HIL, and then for 3 subsequent days. Phospho-activation of the mTOR effectors p70S6kinase and ribosomal S6 protein and expression of hypoxia inducible factor 1 (HIF-1α) were assayed. Neuronal cell death was defined with Fluoro-Jade C (FJC) and autophagy was measured using Beclin-1 and LC3II expression. Iba-1 labeled, activated microglia were quantified. Neuronal death, enhanced HIF-1α expression, and numerous Iba-1 labeled, activated microglia were evident at 24 and 48 h following HIL. Basal mTOR signaling, as evidenced by phosphorylated-S6 and -S6K levels, was unchanged by HIL. Rapamycin or PF-4,708,671 treatment significantly reduced mTOR signaling, neuronal death, HIF-1α expression, and microglial activation, coincident with enhanced expression of Beclin-1 and LC3II, markers of autophagy induction. mTOR pathway inhibition prevented neuronal death and diminished neuroinflammation in this model of CP. Persistent mTOR signaling following HIL suggests a failure of autophagy induction, which may contribute to neuronal death in CP. These results suggest that mTOR signaling may be a novel therapeutic target to reduce neuronal cell death in

  7. CXCR4/CXCL12/CXCR7 axis is functional in neuroendocrine tumors and signals on mTOR.

    Science.gov (United States)

    Circelli, Luisa; Sciammarella, Concetta; Guadagno, Elia; Tafuto, Salvatore; del Basso de Caro, Marialaura; Botti, Giovanni; Pezzullo, Luciano; Aria, Massimo; Ramundo, Valeria; Tatangelo, Fabiana; Losito, Nunzia Simona; Ieranò, Caterina; D'Alterio, Crescenzo; Izzo, Francesco; Ciliberto, Gennaro; Colao, Annamaria; Faggiano, Antongiulio; Scala, Stefania

    2016-04-05

    To evaluate the possible crosstalk between C-X-C chemokine receptor 4 (CXCR4)/C-X-C motif chemokine 12 (CXCL12)/C-X-C chemokine receptor 7 (CXCR7) axis with the mammalian target of rapamycin (mTOR) pathway in neuroendocrine tumors (NETs). Sixty-one human NETs were included into the study. CXCR4/CXCL12/CXCR7 axis and mTOR pathway were assessed by qRT-PCR and immunohistochemistry (IHC). The effect of mTOR inhibitor, RAD001, was evaluated on CXCR4 pathway through proliferation and p-Erk and p-AKT induction. CXCR4/CXCL12/CXCR7 axis and p-mTOR were found to be active and correlated with grading, Ki67 index and tumor stage. mTOR pathway activation significantly correlated with poor prognosis. In human NET cells, CXCL12 induced mTOR signalling while AMD3100 (CXCR4-antagonist) impaired it. The mTOR-antagonist, RAD001, impaired the CXCL12-dependent induction of CXCR4 downstream effectors. Combination of AMD3100 and RAD001 potentiate cell growth inhibition. CXCR4/CXCL12/CXCR7 axis is active in NETs and signals on mTOR. CXCR4 might be considered a prognostic factor in NETs. Combined treatment with AMD3100 and RAD001 may provide clinical benefits in NET patients with drug-resistant.

  8. Correlation between telomerase and mTOR pathway in cancer stem cells.

    Science.gov (United States)

    Dogan, Fatma; Biray Avci, Cigir

    2018-01-30

    Cancer stem cells (CSCs), which are defined as a subset of tumor cells, are able to self-renew, proliferate, differentiate similar to normal stem cells. Therefore, targeting CSCs has been considered as a new approach in cancer therapy. The mammalian target of rapamycin (mTOR) is a receptor tyrosine kinase which plays an important role in regulating cell proliferation, differentiation, cell growth, self-renewal in CSCs. On the other hand, hTERT overactivation provides replicative feature and immortality to CSCs, so the stemness and replicative properties of CSCs depend on telomerase activity. Therefore hTERT/telomerase activity may become a universal biomarker for anticancer therapy and it is an attractive therapeutic target for CSCs. It is known that mTOR regulates telomerase activity at the translational and post-translational level. Researchers show that mTOR inhibitor rapamycin reduces telomerase activity without changing hTERT mRNA activity. Correlation between mTOR and hTERT is important for survival and immortality of cancer cells. In addition, the PI3K/AKT/mTOR signaling pathway and hTERT up-regulation are related with cancer stemness features and drug resistance. mTOR inhibitor and TERT inhibitor combination may construct a novel strategy in cancer stem cells and it can make a double effect on telomerase enzyme. Consequently, inhibition of PI3K/AKT/mTOR signaling pathway components and hTERT activation may prohibit CSC self-renewal and surpass CSC-mediated resistance in order to develop new cancer therapeutics. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Endocrine responses and acute mTOR pathway phosphorylation to resistance exercise with leucine and whey

    Directory of Open Access Journals (Sweden)

    MT Lane

    2017-02-01

    Full Text Available Leucine ingestion reportedly activates the mTOR pathway in skeletal muscle, contributing to a hypertrophy response. The purpose of the study was to compare the post-resistance exercise effects of leucine and whey protein supplementation on endocrine responses and muscle mTOR pathway phosphorylation. On visit 1, subjects (X±SD; n=20; age=27.8±2.8yrs provided baseline blood samples for analysis of cortisol, glucose and insulin; a muscle biopsy of the vastus lateralis muscle to assess mTOR signaling pathway phosphorylation; and were tested for maximum strength on the leg press and leg extension exercises. For visits 2 and 3, subjects were randomized in a double-blind crossover design to ingest either leucine and whey protein (10g+10g; supplement or a non-caloric placebo. During these visits, 5 sets of 10 repetitions were performed on both exercises, immediately followed by ingestion of the supplement or placebo. Blood was sampled 30 min post-, and a muscle biopsy 45 min post-exercise. Western blots quantified total and phosphorylated proteins. Insulin increased (α<.05 with supplementation with no change in glucose compared to placebo. Relative phosphorylation of AKT and rpS6 were greater with leucine and whey supplementation compared to placebo. Supplementation of leucine and whey protein immediately after heavy resistance exercise increases anabolic signaling in human skeletal muscle.

  10. mTOR signaling promotes stem cell activation via counterbalancing BMP-mediated suppression during hair regeneration.

    Science.gov (United States)

    Deng, Zhili; Lei, Xiaohua; Zhang, Xudong; Zhang, Huishan; Liu, Shuang; Chen, Qi; Hu, Huimin; Wang, Xinyue; Ning, Lina; Cao, Yujing; Zhao, Tongbiao; Zhou, Jiaxi; Chen, Ting; Duan, Enkui

    2015-02-01

    Hair follicles (HFs) undergo cycles of degeneration (catagen), rest (telogen), and regeneration (anagen) phases. Anagen begins when the hair follicle stem cells (HFSCs) obtain sufficient activation cues to overcome suppressive signals, mainly the BMP pathway, from their niche cells. Here, we unveil that mTOR complex 1 (mTORC1) signaling is activated in HFSCs, which coincides with the HFSC activation at the telogen-to-anagen transition. By using both an inducible conditional gene targeting strategy and a pharmacological inhibition method to ablate or inhibit mTOR signaling in adult skin epithelium before anagen initiation, we demonstrate that HFs that cannot respond to mTOR signaling display significantly delayed HFSC activation and extended telogen. Unexpectedly, BMP signaling activity is dramatically prolonged in mTOR signaling-deficient HFs. Through both gain- and loss-of-function studies in vitro, we show that mTORC1 signaling negatively affects BMP signaling, which serves as a main mechanism whereby mTORC1 signaling facilitates HFSC activation. Indeed, in vivo suppression of BMP by its antagonist Noggin rescues the HFSC activation defect in mTORC1-null skin. Our findings reveal a critical role for mTOR signaling in regulating stem cell activation through counterbalancing BMP-mediated repression during hair regeneration. © The Author (2015). Published by Oxford University Press on behalf of Journal of Molecular Cell Biology, IBCB, SIBS, CAS. All rights reserved.

  11. Leucine Modulation of the mTOR Pathway for Cognition Modulation: Kinetic and In Vitro Studies and Model Development

    Science.gov (United States)

    2015-09-30

    ultimately at regional levels. In other words , the arrival of free leucine at a tissue site and taken up by the cells would impart a signal for...immunohistochemical techniques and immortalized rat hippocampal cells. Figure 2. Schematic of the Impact of Leucine on the mTOR Protein Synthesis Pathway

  12. Role of nutrients and mTOR signaling in the regulation of pancreatic progenitors development

    Directory of Open Access Journals (Sweden)

    Lynda Elghazi

    2017-06-01

    Full Text Available Objective: Poor fetal nutrition increases the risk of type 2 diabetes in the offspring at least in part by reduced embryonic β-cell growth and impaired function. However, it is not entirely clear how fetal nutrients and growth factors impact β-cells during development to alter glucose homeostasis and metabolism later in life. The current experiments aimed to test the impact of fetal nutrients and growth factors on endocrine development and how these signals acting on mTOR signaling regulate β-cell mass and glucose homeostasis. Method: Pancreatic rudiments in culture were used to study the role of glucose, growth factors, and amino acids on β-cell development. The number and proliferation of pancreatic and endocrine progenitor were assessed in the presence or absence of rapamycin. The impact of mTOR signaling in vivo on pancreas development and glucose homeostasis was assessed in models deficient for mTOR or Raptor in Pdx1 expressing pancreatic progenitors. Results: We found that amino acid concentrations, and leucine in particular, enhance the number of pancreatic and endocrine progenitors and are essential for growth factor induced proliferation. Rapamycin, an mTORC1 complex inhibitor, reduced the number and proliferation of pancreatic and endocrine progenitors. Mice lacking mTOR in pancreatic progenitors exhibited hyperglycemia in neonates, hypoinsulinemia and pancreatic agenesis/hypoplasia with pancreas rudiments containing ductal structures lacking differentiated acinar and endocrine cells. In addition, loss of mTORC1 by deletion of raptor in pancreatic progenitors reduced pancreas size with reduced number of β-cells. Conclusion: Together, these results suggest that amino acids concentrations and in particular leucine modulates growth responses of pancreatic and endocrine progenitors and that mTOR signaling is critical for these responses. Inactivation of mTOR and raptor in pancreatic progenitors suggested that alterations in some of

  13. FXR blocks the growth of liver cancer cells through inhibiting mTOR-s6K pathway

    International Nuclear Information System (INIS)

    Huang, Xiongfei; Zeng, Yeting; Wang, Xinrui; Ma, Xiaoxiao; Li, Qianqian; Li, Ningbo; Su, Hongying; Huang, Wendong

    2016-01-01

    The nuclear receptor Farnesoid X Receptor (FXR) is likely a tumor suppressor in liver tissue but its molecular mechanism of suppression is not well understood. In this study, the gene expression profile of human liver cancer cells was investigated by microarray. Bioinformatics analysis of these data revealed that FXR might regulate the mTOR/S6K signaling pathway. This was confirmed by altering the expression level of FXR in liver cancer cells. Overexpression of FXR prevented the growth of cells and induced cell cycle arrest, which was enhanced by the mTOR/S6K inhibitor rapamycin. FXR upregulation also intensified the inhibition of cell growth by rapamycin. Downregulation of FXR produced the opposite effect. Finally, we found that ectopic expression of FXR in SK-Hep-1 xenografts inhibits tumor growth and reduces expression of the phosphorylated protein S6K. Taken together, our data provide the first evidence that FXR suppresses proliferation of human liver cancer cells via the inhibition of the mTOR/S6K signaling pathway. FXR expression can be used as a biomarker of personalized mTOR inhibitor treatment assessment for liver cancer patients. -- Highlights: •FXR inhibits the proliferation of liver cancer cells by prolonging G0/G1 phase. •Microarray results indicate that mTOR-S6k signaling is involved in cellular processes in which FXR plays an important role. •FXR blocks the growth of liver cancer cells via the inhibition of the mTOR/S6K signaling pathway in vitro and in vivo.

  14. FXR blocks the growth of liver cancer cells through inhibiting mTOR-s6K pathway

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Xiongfei, E-mail: xiongfeihuang@hotmail.com [Department of Pathology and Institute of Oncology, Preclinical School, Fujian Medical University, Fuzhou 350108, Fujian (China); Key Laboratory of Ministry of Education for Gastrointestinal Cancer, Fujian Medical University, Fuzhou 350108, Fujian (China); Zeng, Yeting [Department of Pathology and Institute of Oncology, Preclinical School, Fujian Medical University, Fuzhou 350108, Fujian (China); Wang, Xinrui [Department of Biochemistry and Molecular Biology, Fujian Medical University, Fuzhou 350108, Fujian (China); Ma, Xiaoxiao [Department of Diabetes Complications and Metabolism, Diabetes & Metabolism Research Institute, Beckman Research Institute, City of Hope, CA 91010 (United States); Li, Qianqian; Li, Ningbo; Su, Hongying [Department of Pathology and Institute of Oncology, Preclinical School, Fujian Medical University, Fuzhou 350108, Fujian (China); Huang, Wendong [Department of Diabetes Complications and Metabolism, Diabetes & Metabolism Research Institute, Beckman Research Institute, City of Hope, CA 91010 (United States)

    2016-05-27

    The nuclear receptor Farnesoid X Receptor (FXR) is likely a tumor suppressor in liver tissue but its molecular mechanism of suppression is not well understood. In this study, the gene expression profile of human liver cancer cells was investigated by microarray. Bioinformatics analysis of these data revealed that FXR might regulate the mTOR/S6K signaling pathway. This was confirmed by altering the expression level of FXR in liver cancer cells. Overexpression of FXR prevented the growth of cells and induced cell cycle arrest, which was enhanced by the mTOR/S6K inhibitor rapamycin. FXR upregulation also intensified the inhibition of cell growth by rapamycin. Downregulation of FXR produced the opposite effect. Finally, we found that ectopic expression of FXR in SK-Hep-1 xenografts inhibits tumor growth and reduces expression of the phosphorylated protein S6K. Taken together, our data provide the first evidence that FXR suppresses proliferation of human liver cancer cells via the inhibition of the mTOR/S6K signaling pathway. FXR expression can be used as a biomarker of personalized mTOR inhibitor treatment assessment for liver cancer patients. -- Highlights: •FXR inhibits the proliferation of liver cancer cells by prolonging G0/G1 phase. •Microarray results indicate that mTOR-S6k signaling is involved in cellular processes in which FXR plays an important role. •FXR blocks the growth of liver cancer cells via the inhibition of the mTOR/S6K signaling pathway in vitro and in vivo.

  15. mTOR signaling and its roles in normal and abnormal brain development.

    Directory of Open Access Journals (Sweden)

    Nobuyuki eTakei

    2014-04-01

    Full Text Available Target of rapamycin (TOR was first identified in yeast as a target molecule of rapamycin, an anti-fugal and immunosuppressant macrolide compound. In mammals, its orthologue is called mTOR (mammalian TOR. mTOR is a serine/threonine kinase that converges different extracellular stimuli, such as nutrients and growth factors, and diverges into several biochemical reactions, including translation, autophagy, transcription, and lipid synthesis among others. These biochemical reactions govern cell growth and cause cells to attain an anabolic state. Thus, the disruption of mTOR signaling is implicated in a wide array of diseases such as cancer, diabetes, and obesity. In the central nervous system (CNS, the mTOR signaling cascade is activated by nutrients, neurotrophic factors, and neurotransmitters that enhances protein (and possibly lipid synthesis and suppresses autophagy. These processes contribute to normal neuronal growth by promoting their differentiation, neurite elongation and branching, and synaptic formation during development. Therefore, disruption of mTOR signaling may cause neuronal degeneration and abnormal neural development. While reduced mTOR signaling is associated with neurodegeneration, excess activation of mTOR signaling causes abnormal development of neurons and glia, leading to brain malformation. In this review, we first introduce the current state of molecular knowledge of mTOR complexes and signaling in general. We then describe mTOR activation in neurons, which leads to translational enhancement, and finally discuss the link between mTOR and normal/abnormal neuronal growth during development.

  16. Estradiol-Induced Object Recognition Memory Consolidation Is Dependent on Activation of mTOR Signaling in the Dorsal Hippocampus

    Science.gov (United States)

    Fortress, Ashley M.; Fan, Lu; Orr, Patrick T.; Zhao, Zaorui; Frick, Karyn M.

    2013-01-01

    The mammalian target of rapamycin (mTOR) signaling pathway is an important regulator of protein synthesis and is essential for various forms of hippocampal memory. Here, we asked whether the enhancement of object recognition memory consolidation produced by dorsal hippocampal infusion of 17[Beta]-estradiol (E[subscript 2]) is dependent on mTOR…

  17. Effective Therapeutic Intervention and Comprehensive Genetic Analysis of mTOR Signaling in PEComa : A Case Report

    NARCIS (Netherlands)

    Weeber, Fleur; Koudijs, Marco J; Hoogstraat, Marlous; Besselink, Nicolle J M; VAN Lieshout, Stef; Nijman, Isaac J; Cuppen, Edwin; Offerhaus, G Johan; Voest, Emile E

    BACKGROUND/AIM: Perivascular epithelioid cell tumors (PEComas) are rare mesenchymal neoplasms. The exact genetic alterations underlying the pathophysiology of PEComas are largely unknown, although it has been shown that activation of the Mammalian target of rapamycin (mTOR) signaling pathway plays a

  18. ESCMID Study Group for Infections in Compromised Hosts (ESGICH) Consensus Document on the safety of targeted and biological therapies: an infectious diseases perspective (Intracellular signaling pathways: tyrosine kinase and mTOR inhibitors).

    Science.gov (United States)

    Reinwald, M; Silva, J T; Mueller, N J; Fortún, J; Garzoni, C; de Fijter, J W; Fernández-Ruiz, M; Grossi, P; Aguado, J M

    2018-06-01

    The present review is part of the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) Study Group for Infections in Compromised Hosts (ESGICH) Consensus Document on the safety of targeted and biologic therapies. To review, from an infectious diseases perspective, the safety profile of therapies targeting different intracellular signaling pathways and to suggest preventive recommendations. Computer-based Medline searches with MeSH terms pertaining to each agent or therapeutic family. Although BCR-ABL tyrosine kinase inhibitors modestly increase the overall risk of infection, dasatinib has been associated with cytomegalovirus and hepatitis B virus reactivation. BRAF/MEK kinase inhibitors do not significantly affect infection susceptibility. The effect of Bruton tyrosine kinase inhibitors (ibrutinib) among patients with B-cell malignancies is difficult to distinguish from that of previous immunosuppression. However, cases of Pneumocystis jirovecii pneumonia (PCP), invasive fungal infection and progressive multifocal leukoencephalopathy have been occasionally reported. Because phosphatidylinositol-3-kinase inhibitors (idelalisib) may predispose to opportunistic infections, anti-Pneumocystis prophylaxis and prevention strategies for cytomegalovirus are recommended. No increased rates of infection have been observed with venetoclax (antiapoptotic protein Bcl-2 inhibitor). Therapy with Janus kinase inhibitors markedly increases the incidence of infection. Pretreatment screening for chronic hepatitis B virus and latent tuberculosis infection must be performed, and anti-Pneumocystis prophylaxis should be considered for patients with additional risk factors. Cancer patients receiving mTOR inhibitors face an increased incidence of overall infection, especially those with additional risk factors (prior therapies or delayed wound healing). Specific preventive approaches are warranted in view of the increased risk of infection associated with some of the

  19. FK866-induced NAMPT inhibition activates AMPK and downregulates mTOR signaling in hepatocarcinoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Schuster, Susanne, E-mail: Susanne.Schuster@medizin.uni-leipzig.de [Center for Pediatric Research Leipzig, University Hospital for Children and Adolescents, Faculty of Medicine, University of Leipzig, Liebigstr. 21, 04103 Leipzig (Germany); Penke, Melanie; Gorski, Theresa [Center for Pediatric Research Leipzig, University Hospital for Children and Adolescents, Faculty of Medicine, University of Leipzig, Liebigstr. 21, 04103 Leipzig (Germany); Gebhardt, Rolf [Institute of Biochemistry, Faculty of Medicine, University of Leipzig, Johannisallee 30, 04103 Leipzig (Germany); Weiss, Thomas S. [Children' s University Hospital, University of Regensburg, Franz-Josef-Strauss-Allee 11, 93053 Regensburg (Germany); Kiess, Wieland; Garten, Antje [Center for Pediatric Research Leipzig, University Hospital for Children and Adolescents, Faculty of Medicine, University of Leipzig, Liebigstr. 21, 04103 Leipzig (Germany)

    2015-03-06

    Background: Nicotinamide phosphoribosyltransferase (NAMPT) is the key enzyme of the NAD salvage pathway starting from nicotinamide. Cancer cells have an increased demand for NAD due to their high proliferation and DNA repair rate. Consequently, NAMPT is considered as a putative target for anti-cancer therapies. There is evidence that AMP-activated protein kinase (AMPK) and mammalian target of rapamycin (mTOR) become dysregulated during the development of hepatocellular carcinoma (HCC). Here, we investigated the effects of NAMPT inhibition by its specific inhibitor FK866 on the viability of hepatocarcinoma cells and analyzed the effects of FK866 on the nutrient sensor AMPK and mTOR complex1 (mTORC1) signaling. Results: FK866 markedly decreased NAMPT activity and NAD content in hepatocarcinoma cells (Huh7 cells, Hep3B cells) and led to delayed ATP reduction which was associated with increased cell death. These effects could be abrogated by administration of nicotinamide mononucleotide (NMN), the enzyme product of NAMPT. Our results demonstrated a dysregulation of the AMPK/mTOR pathway in hepatocarcinoma cells compared to non-cancerous hepatocytes with a higher expression of mTOR and a lower AMPKα activation in hepatocarcinoma cells. We found that NAMPT inhibition by FK866 significantly activated AMPKα and inhibited the activation of mTOR and its downstream targets p70S6 kinase and 4E-BP1 in hepatocarcinoma cells. Non-cancerous hepatocytes were less sensitive to FK866 and did not show changes in AMPK/mTOR signaling after FK866 treatment. Conclusion: Taken together, these findings reveal an important role of the NAMPT-mediated NAD salvage pathway in the energy homeostasis of hepatocarcinoma cells and suggest NAMPT inhibition as a potential treatment option for HCC. - Highlights: • FK866 increases cell death in p53-deficient hepatocarcinoma cells. • AMPK/mTOR signaling is dysregulated in hepatocarcinoma cells. • FK866-induced NAMPT inhibition activates AMPK

  20. FK866-induced NAMPT inhibition activates AMPK and downregulates mTOR signaling in hepatocarcinoma cells

    International Nuclear Information System (INIS)

    Schuster, Susanne; Penke, Melanie; Gorski, Theresa; Gebhardt, Rolf; Weiss, Thomas S.; Kiess, Wieland; Garten, Antje

    2015-01-01

    Background: Nicotinamide phosphoribosyltransferase (NAMPT) is the key enzyme of the NAD salvage pathway starting from nicotinamide. Cancer cells have an increased demand for NAD due to their high proliferation and DNA repair rate. Consequently, NAMPT is considered as a putative target for anti-cancer therapies. There is evidence that AMP-activated protein kinase (AMPK) and mammalian target of rapamycin (mTOR) become dysregulated during the development of hepatocellular carcinoma (HCC). Here, we investigated the effects of NAMPT inhibition by its specific inhibitor FK866 on the viability of hepatocarcinoma cells and analyzed the effects of FK866 on the nutrient sensor AMPK and mTOR complex1 (mTORC1) signaling. Results: FK866 markedly decreased NAMPT activity and NAD content in hepatocarcinoma cells (Huh7 cells, Hep3B cells) and led to delayed ATP reduction which was associated with increased cell death. These effects could be abrogated by administration of nicotinamide mononucleotide (NMN), the enzyme product of NAMPT. Our results demonstrated a dysregulation of the AMPK/mTOR pathway in hepatocarcinoma cells compared to non-cancerous hepatocytes with a higher expression of mTOR and a lower AMPKα activation in hepatocarcinoma cells. We found that NAMPT inhibition by FK866 significantly activated AMPKα and inhibited the activation of mTOR and its downstream targets p70S6 kinase and 4E-BP1 in hepatocarcinoma cells. Non-cancerous hepatocytes were less sensitive to FK866 and did not show changes in AMPK/mTOR signaling after FK866 treatment. Conclusion: Taken together, these findings reveal an important role of the NAMPT-mediated NAD salvage pathway in the energy homeostasis of hepatocarcinoma cells and suggest NAMPT inhibition as a potential treatment option for HCC. - Highlights: • FK866 increases cell death in p53-deficient hepatocarcinoma cells. • AMPK/mTOR signaling is dysregulated in hepatocarcinoma cells. • FK866-induced NAMPT inhibition activates AMPK

  1. Reduced AMPK-ACC and mTOR signaling in muscle from older men, and effect of resistance exercise.

    Science.gov (United States)

    Li, Mengyao; Verdijk, Lex B; Sakamoto, Kei; Ely, Brian; van Loon, Luc J C; Musi, Nicolas

    2012-01-01

    AMP-activated protein kinase (AMPK) is a key energy-sensitive enzyme that controls numerous metabolic and cellular processes. Mammalian target of rapamycin (mTOR) is another energy/nutrient-sensitive kinase that controls protein synthesis and cell growth. In this study we determined whether older versus younger men have alterations in the AMPK and mTOR pathways in skeletal muscle, and examined the effect of a long term resistance type exercise training program on these signaling intermediaries. Older men had decreased AMPKα2 activity and lower phosphorylation of AMPK and its downstream signaling substrate acetyl-CoA carboxylase (ACC). mTOR phosphylation also was reduced in muscle from older men. Exercise training increased AMPKα1 activity in older men, however, AMPKα2 activity, and the phosphorylation of AMPK, ACC and mTOR, were not affected. In conclusion, older men have alterations in the AMPK-ACC and mTOR pathways in muscle. In addition, prolonged resistance type exercise training induces an isoform-selective up regulation of AMPK activity. Published by Elsevier Ireland Ltd.

  2. Androgen interacts with exercise through the mTOR pathway to induce skeletal muscle hypertrophy.

    Science.gov (United States)

    Zeng, Fanxing; Zhao, Hua; Liao, Jingwen

    2017-12-01

    This study was designed to investigate the effects of exogenous androgen and resistance exercise on skeletal muscle hypertrophy and the role of the mammalian target of rapamycin (mTOR) signalling during the process. A total of 24 male Sprague-Dawley rats were randomly assigned to sham operation and dihydrotestosterone (DHT) implantation groups with subgroups subjected to sedentary conditions or resistance exercise (SHAM+SED, SHAM+EX, DHT+SED, and DHT+EX). The experimental procedure lasted for 10 days. The mRNA expression of androgen receptor (AR) and insulin-like growth factor I (IGF-I), the expression of myosin heavy chain (MHC), as well as the phosphorylation statuses of AR, mTOR, p70 ribosomal S6 kinase (p70 S6K ), and eukaryotic translation initiation factor 4E-binding protein 1 (4EBP1) were determined in the white gastrocnemius muscle. The cross sectional area and wet mass of the muscle were also measured. The cross sectional area and MHC expression were significantly higher in SHAM+EX, DHT+SED, and DHT+EX than in SHAM+SED. There was no significant difference among groups in muscle mass. The mRNA expression of AR and IGF-I and the phosphorylation of mTOR, p70 S6K , and 4EBP1 were significantly increased in DHT+SED and SHAM+EX and were significantly enhanced in DHT+EX compared with either DHT or exercise alone. These data show that DHT causes hypertrophy in skeletal muscle and that exercise has a synergistic effect on DHT-induced hypertrophy. Exercise enhances androgen-induced rapid anabolic action, which involves activation of the mTOR pathway.

  3. mTOR signaling plays a critical role in the defects observed in muscle-derived stem/progenitor cells isolated from a murine model of accelerated aging.

    Science.gov (United States)

    Takayama, Koji; Kawakami, Yohei; Lavasani, Mitra; Mu, Xiaodong; Cummins, James H; Yurube, Takashi; Kuroda, Ryosuke; Kurosaka, Masahiro; Fu, Freddie H; Robbins, Paul D; Niedernhofer, Laura J; Huard, Johnny

    2017-07-01

    Mice expressing reduced levels of ERCC1-XPF (Ercc1 -/Δ mice) demonstrate premature onset of age-related changes due to decreased repair of DNA damage. Muscle-derived stem/progenitor cells (MDSPCs) isolated from Ercc1 -/Δ mice have an impaired capacity for cell differentiation. The mammalian target of rapamycin (mTOR) is a critical regulator of cell growth in response to nutrient, hormone, and oxygen levels. Inhibition of the mTOR pathway extends the lifespan of several species. Here, we examined the role of mTOR in regulating the MDSPC dysfunction that occurs with accelerated aging. We show that mTOR signaling pathways are activated in Ercc1 -/Δ MDSPCs compared with wild-type (WT) MDSPCs. Additionally, inhibiting mTOR with rapamycin promoted autophagy and improved the myogenic differentiation capacity of the Ercc1 -/Δ MDSPCs. The percent of apoptotic and senescent cells in Ercc1 -/Δ MDSPC cultures was decreased upon mTOR inhibition. These results establish that mTOR signaling contributes to stem cell dysfunction and cell fate decisions in response to endogenous DNA damage. Therefore, mTOR represents a potential therapeutic target for improving defective, aged stem cells. © 2016 The Authors. Journal of Orthopaedic Research Published by Wiley Periodicals, Inc. on behalf of Orthopaedic Research Society. J Orthop Res 35:1375-1382, 2017. © 2016 The Authors. Journal of Orthopaedic Research Published by Wiley Periodicals, Inc. on behalf of Orthopaedic Research Society.

  4. Repression of protein translation and mTOR signaling by proteasome inhibitor in colon cancer cells

    International Nuclear Information System (INIS)

    Wu, William Ka Kei; Volta, Viviana; Cho, Chi Hin; Wu, Ya Chun; Li, Hai Tao; Yu, Le; Li, Zhi Jie; Sung, Joseph Jao Yiu

    2009-01-01

    Protein homeostasis relies on a balance between protein synthesis and protein degradation. The ubiquitin-proteasome system is a major catabolic pathway for protein degradation. In this respect, proteasome inhibition has been used therapeutically for the treatment of cancer. Whether inhibition of protein degradation by proteasome inhibitor can repress protein translation via a negative feedback mechanism, however, is unknown. In this study, proteasome inhibitor MG-132 lowered the proliferation of colon cancer cells HT-29 and SW1116. In this connection, MG-132 reduced the phosphorylation of mammalian target of rapamycin (mTOR) at Ser2448 and Ser2481 and the phosphorylation of its downstream targets 4E-BP1 and p70/p85 S6 kinases. Further analysis revealed that MG-132 inhibited protein translation as evidenced by the reductions of 35 S-methionine incorporation and polysomes/80S ratio. Knockdown of raptor, a structural component of mTOR complex 1, mimicked the anti-proliferative effect of MG-132. To conclude, we demonstrate that the inhibition of protein degradation by proteasome inhibitor represses mTOR signaling and protein translation in colon cancer cells.

  5. The proliferation of amplifying neural progenitor cells is impaired in the aging brain and restored by the mTOR pathway activation.

    Science.gov (United States)

    Romine, Jennifer; Gao, Xiang; Xu, Xiao-Ming; So, Kwok Fai; Chen, Jinhui

    2015-04-01

    A decrease in neurogenesis in the aged brain has been correlated with cognitive decline. The molecular signaling that regulates age-related decline in neurogenesis is still not fully understood. We found that different subtypes of neural stem cells (NSCs) in the hippocampus were differentially impaired by aging. The quiescent NSCs decreased slowly, although the active NSCs exhibited a sharp and dramatic decline from the ages of 6-9 months and became more quiescent at an early stage during the aging process. The activity of the mammalian target of rapamycin (mTOR) signal pathway is compromised in the NSCs of the aged brain. Activating the mTOR signaling pathway increased NSC proliferation and promoted neurogenesis in aged mice. In contrast, inhibiting the mTOR signaling pathway decreased NSCs proliferation. These results indicate that an age-associated decline in neurogenesis is mainly because of the reduction in proliferation of active NSCs, at least partially because of the compromise in the mTOR signaling activity. Stimulating the mTOR signaling revitalizes the NSCs, restores their proliferation, and enhances neurogenesis in the hippocampus of the aged brain. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. A chemical genetic screen for mTOR pathway inhibitors based on 4E-BP-dependent nuclear accumulation of eIF4E.

    Science.gov (United States)

    Livingstone, Mark; Larsson, Ola; Sukarieh, Rami; Pelletier, Jerry; Sonenberg, Nahum

    2009-12-24

    The signal transduction pathway wherein mTOR regulates cellular growth and proliferation is an active target for drug discovery. The search for new mTOR inhibitors has recently yielded a handful of promising compounds that hold therapeutic potential. This search has been limited by the lack of a high-throughput assay to monitor the phosphorylation of a direct rapamycin-sensitive mTOR substrate in cells. Here we describe a novel cell-based chemical genetic screen useful for efficiently monitoring mTOR signaling to 4E-BPs in response to stimuli. The screen is based on the nuclear accumulation of eIF4E, which occurs in a 4E-BP-dependent manner specifically upon inhibition of mTOR signaling. Using this assay in a small-scale screen, we have identified several compounds not previously known to inhibit mTOR signaling, demonstrating that this method can be adapted to larger screens. Copyright 2009 Elsevier Ltd. All rights reserved.

  7. Genetic variability of the mTOR pathway and prostate cancer risk in the European Prospective Investigation on Cancer (EPIC.

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    Daniele Campa

    2011-02-01

    Full Text Available The mTOR (mammalian target of rapamycin signal transduction pathway integrates various signals, regulating ribosome biogenesis and protein synthesis as a function of available energy and amino acids, and assuring an appropriate coupling of cellular proliferation with increases in cell size. In addition, recent evidence has pointed to an interplay between the mTOR and p53 pathways. We investigated the genetic variability of 67 key genes in the mTOR pathway and in genes of the p53 pathway which interact with mTOR. We tested the association of 1,084 tagging SNPs with prostate cancer risk in a study of 815 prostate cancer cases and 1,266 controls nested within the European Prospective Investigation into Cancer and Nutrition (EPIC. We chose the SNPs (n = 11 with the strongest association with risk (p<0.01 and sought to replicate their association in an additional series of 838 prostate cancer cases and 943 controls from EPIC. In the joint analysis of first and second phase two SNPs of the PRKCI gene showed an association with risk of prostate cancer (OR(allele = 0.85, 95% CI 0.78-0.94, p = 1.3 x 10⁻³ for rs546950 and OR(allele = 0.84, 95% CI 0.76-0.93, p = 5.6 x 10⁻⁴ for rs4955720. We confirmed this in a meta-analysis using as replication set the data from the second phase of our study jointly with the first phase of the Cancer Genetic Markers of Susceptibility (CGEMS project. In conclusion, we found an association with prostate cancer risk for two SNPs belonging to PRKCI, a gene which is frequently overexpressed in various neoplasms, including prostate cancer.

  8. Biphasic activation of the mTOR pathway in the gustatory cortex is correlated with and necessary for taste learning.

    Science.gov (United States)

    Belelovsky, Katya; Kaphzan, Hanoch; Elkobi, Alina; Rosenblum, Kobi

    2009-06-10

    Different forms of memories and synaptic plasticity require synthesis of new proteins at the time of acquisition or immediately after. We are interested in the role of translation regulation in the cortex, the brain structure assumed to store long-term memories. The mammalian target of rapamycin, mTOR (also known as FRAP and RAFT-1), is part of a key signal transduction mechanism known to regulate translation of specific subset of mRNAs and to affect learning and synaptic plasticity. We report here that novel taste learning induces two waves of mTOR activation in the gustatory cortex. Interestingly, the first wave can be identified both in synaptoneurosomal and cellular fractions, whereas the second wave is detected in the cellular fraction but not in the synaptic one. Inhibition of mTOR, specifically in the gustatory cortex, has two effects. First, biochemically, it modulates several known downstream proteins that control translation and reduces the expression of postsynaptic density-95 in vivo. Second, behaviorally, it attenuates long-term taste memory. The results suggest that the mTOR pathway in the cortex modulates both translation factor activity and protein expression, to enable normal taste memory consolidation.

  9. Regulation of androgen receptor transactivity and mTOR-S6 kinase pathway by Rheb in prostate cancer cell proliferation.

    Science.gov (United States)

    Kobayashi, Takashi; Shimizu, Yosuke; Terada, Naoki; Yamasaki, Toshinari; Nakamura, Eijiro; Toda, Yoshinobu; Nishiyama, Hiroyuki; Kamoto, Toshiyuki; Ogawa, Osamu; Inoue, Takahiro

    2010-06-01

    Ras homolog-enriched in brain (Rheb), a small GTP-binding protein, is associated with prostate carcinogenesis through activating mammalian target of rapamycin (mTOR) signaling pathway. This study aimed to elucidate whether Rheb promotes proliferation of prostate cancer cells and can act as a potent therapeutic target in prostate cancer. Prostate cancer cell lines and human prostatic tissues were examined for the expression of Rheb. The effects of forced expression or knockdown of Rheb on cell proliferation were also examined. Semi-quantitative and quantitative RT-PCR were performed to evaluate mRNA expression. Western blotting was used to examine protein expression. Cell count and WST-1 assay were used to measure cell proliferation. Fluorescence-activated cell sorting was used to assess the cell cycle. Rheb mRNA and protein expression was higher in more aggressive, androgen-independent prostate cancer cell lines PC3, DU145, and C4-2, compared with the less aggressive LNCaP. Rheb expression was higher in cancer tissues than in benign prostatic epithelia. Forced expression of Rheb in LNCaP cells accelerated proliferation without enhancing androgen receptor transactivity. Attenuation of Rheb expression or treatment with the mTOR inhibitor rapamycin decreased proliferation of PC3 and DU145 cells, with a decrease in the activated form of p70S6 kinase, one of the main targets of mTOR. Rheb potentiates proliferation of prostate cancer cells and inhibition of Rheb or mTOR can lead to suppressed proliferation of aggressive prostate cancer cell lines in vitro. Rheb and the mTOR pathway are therefore probable targets for suppressing prostate cancer.

  10. FRS2α is Essential for the Fibroblast Growth Factor to Regulate the mTOR Pathway and Autophagy in Mouse Embryonic Fibroblasts

    OpenAIRE

    Xiang Lin, Yongyou Zhang, Leyuan Liu, Wallace L. McKeehan, Yuemao Shen, Siyang Song, Fen Wang

    2011-01-01

    Although the fibroblast growth factor (FGF) signaling axis plays important roles in cell survival, proliferation, and differentiation, the molecular mechanism underlying how the FGF elicits these diverse regulatory signals is not well understood. By using the Frs2α null mouse embryonic fibroblast (MEF) in conjunction with inhibitors to multiple signaling pathways, here we report that the FGF signaling axis activates mTOR via the FGF receptor substrate 2α (FRS2α)-mediated PI3K/A...

  11. miR-199a Links MeCP2 with mTOR Signaling and Its Dysregulation Leads to Rett Syndrome Phenotypes

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    Keita Tsujimura

    2015-09-01

    Full Text Available Rett syndrome (RTT is a neurodevelopmental disorder caused by MECP2 mutations. Although emerging evidence suggests that MeCP2 deficiency is associated with dysregulation of mechanistic target of rapamycin (mTOR, which functions as a hub for various signaling pathways, the mechanism underlying this association and the molecular pathophysiology of RTT remain elusive. We show here that MeCP2 promotes the posttranscriptional processing of particular microRNAs (miRNAs as a component of the microprocessor Drosha complex. Among the MeCP2-regulated miRNAs, we found that miR-199a positively controls mTOR signaling by targeting inhibitors for mTOR signaling. miR-199a and its targets have opposite effects on mTOR activity, ameliorating and inducing RTT neuronal phenotypes, respectively. Furthermore, genetic deletion of miR-199a-2 led to a reduction of mTOR activity in the brain and recapitulated numerous RTT phenotypes in mice. Together, these findings establish miR-199a as a critical downstream target of MeCP2 in RTT pathogenesis by linking MeCP2 with mTOR signaling.

  12. Fasting Increases Human Skeletal Muscle Net Phenylalanine Release and This Is Associated with Decreased mTOR Signaling

    Science.gov (United States)

    Vendelbo, Mikkel Holm; Møller, Andreas Buch; Christensen, Britt; Nellemann, Birgitte; Clasen, Berthil Frederik Forrest; Nair, K. Sreekumaran; Jørgensen, Jens Otto Lunde; Jessen, Niels; Møller, Niels

    2014-01-01

    Aim Fasting is characterised by profound changes in energy metabolism including progressive loss of body proteins. The underlying mechanisms are however unknown and we therefore determined the effects of a 72-hour-fast on human skeletal muscle protein metabolism and activation of mammalian target of rapamycin (mTOR), a key regulator of cell growth. Methods Eight healthy male volunteers were studied twice: in the postabsorptive state and following 72 hours of fasting. Regional muscle amino acid kinetics was measured in the forearm using amino acid tracers. Signaling to protein synthesis and breakdown were assessed in skeletal muscle biopsies obtained during non-insulin and insulin stimulated conditions on both examination days. Results Fasting significantly increased forearm net phenylalanine release and tended to decrease phenylalanine rate of disappearance. mTOR phosphorylation was decreased by ∼50% following fasting, together with reduced downstream phosphorylation of 4EBP1, ULK1 and rpS6. In addition, the insulin stimulated increase in mTOR and rpS6 phosphorylation was significantly reduced after fasting indicating insulin resistance in this part of the signaling pathway. Autophagy initiation is in part regulated by mTOR through ULK1 and fasting increased expression of the autophagic marker LC3B-II by ∼30%. p62 is degraded during autophagy but was increased by ∼10% during fasting making interpretation of autophagic flux problematic. MAFbx and MURF1 ubiquitin ligases remained unaltered after fasting indicating no change in protesomal protein degradation. Conclusions Our results show that during fasting increased net phenylalanine release in skeletal muscle is associated to reduced mTOR activation and concomitant decreased downstream signaling to cell growth. PMID:25020061

  13. Fasting increases human skeletal muscle net phenylalanine release and this is associated with decreased mTOR signaling.

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    Mikkel Holm Vendelbo

    Full Text Available Fasting is characterised by profound changes in energy metabolism including progressive loss of body proteins. The underlying mechanisms are however unknown and we therefore determined the effects of a 72-hour-fast on human skeletal muscle protein metabolism and activation of mammalian target of rapamycin (mTOR, a key regulator of cell growth.Eight healthy male volunteers were studied twice: in the postabsorptive state and following 72 hours of fasting. Regional muscle amino acid kinetics was measured in the forearm using amino acid tracers. Signaling to protein synthesis and breakdown were assessed in skeletal muscle biopsies obtained during non-insulin and insulin stimulated conditions on both examination days.Fasting significantly increased forearm net phenylalanine release and tended to decrease phenylalanine rate of disappearance. mTOR phosphorylation was decreased by ∼50% following fasting, together with reduced downstream phosphorylation of 4EBP1, ULK1 and rpS6. In addition, the insulin stimulated increase in mTOR and rpS6 phosphorylation was significantly reduced after fasting indicating insulin resistance in this part of the signaling pathway. Autophagy initiation is in part regulated by mTOR through ULK1 and fasting increased expression of the autophagic marker LC3B-II by ∼30%. p62 is degraded during autophagy but was increased by ∼10% during fasting making interpretation of autophagic flux problematic. MAFbx and MURF1 ubiquitin ligases remained unaltered after fasting indicating no change in protesomal protein degradation.Our results show that during fasting increased net phenylalanine release in skeletal muscle is associated to reduced mTOR activation and concomitant decreased downstream signaling to cell growth.

  14. mTOR inhibition in macrophages of asymptomatic HIV+ persons reverses the decrease in TLR4-mediated TNFα release through prolongation of MAPK pathway activation1

    Science.gov (United States)

    Li, Xin; Han, Xinbing; Llano, Juliana; Bole, Medhavi; Zhou, Xiuqin; Swan, Katharine; Anandaiah, Asha; Nelson, Benjamin; Patel, Naimish R.; Reinach, Peter S.; Koziel, Henry; Tachado, Souvenir D.

    2011-01-01

    Toll-like receptor 4 (TLR4) mediated signaling is significantly impaired in macrophages from HIV+ persons predominantly due to altered MyD88-dependent pathway signaling caused in part by constitutive activation of PI3K. Here we assessed in these macrophages if the blunted increase in TLR4-mediated TNFα release induced by lipid A are associated with PI3K-induced upregulation of mammalian target of rapamycin (mTOR) activity. mTOR inhibition with rapamycin enhanced TLR4-mediated TNFα release, but instead suppressed anti-inflammatory IL-10 release. Targeted gene silencing of mTOR in macrophages resulted in lipid A-induced TNFα and IL-10 release patterns similar to those induced by rapamycin. Rapamycin restored MyD88-IRAK interaction in a dose-dependent manner. Targeted gene silencing of MyD88 (shRNA) and mTOR (RNAi) inhibition resulted in TLR4-mediated p70s6K activation and enhanced TNFα release, whereas IL-10 release was inhibited in both silenced and non-silenced HIV+ macrophages. Furthermore, mTOR inhibition augmented lipid A-induced TNFα release through enhanced and prolonged phosphorylation of ERK1/2 and JNK1/2 MAP kinases, which was associated with time-dependent MKP-1 destabilization. Taken together, impaired TLR4-mediated TNFα release in HIV+ macrophages is attributable in part to mTOR activation by constitutive PI3K expression in a MyD88-dependent signaling pathway. These changes result in MKP-1 stabilization, which shortens and blunts MAP kinase activation. mTOR inhibition may serve as a potential therapeutic target to upregulate macrophage innate immune host defense responsiveness in HIV+ persons. PMID:22025552

  15. Hormone resistance in two MCF-7 breast cancer cell lines is associated with reduced mTOR signaling, decreased glycolysis and increased sensitivity to cytotoxic drugs

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    Euphemia Yee Leung

    2014-09-01

    Full Text Available The mTOR pathway is a key regulator of multiple cellular signaling pathways and is a potential target for therapy. We have previously developed two hormone-resistant sub-lines of the MCF-7 human breast cancer line, designated TamC3 and TamR3, which were characterized by reduced mTOR signaling, reduced cell volume and resistance to mTOR inhibition. Here we show that these lines exhibit increased sensitivity to carboplatin, oxaliplatin, 5-fluorouracil, camptothecin, doxorubicin, paclitaxel, docetaxel and hydrogen peroxide. The mechanisms underlying these changes have not yet been characterized but may include a shift from glycolysis to mitochondrial respiration. If this phenotype is found in clinical hormone-resistant breast cancers, conventional cytotoxic therapy may be a preferred option for treatment.

  16. Outside-in HLA class I signaling regulates ICAM-1 clustering and endothelial cell-monocyte interactions via mTOR in transplant antibody-mediated rejection.

    Science.gov (United States)

    Salehi, Sahar; Sosa, Rebecca A; Jin, Yi-Ping; Kageyama, Shoichi; Fishbein, Michael C; Rozengurt, Enrique; Kupiec-Weglinski, Jerzy W; Reed, Elaine F

    2018-05-01

    Antibody-mediated rejection (AMR) resulting in transplant allograft vasculopathy (TAV) is the major obstacle for long-term survival of solid organ transplants. AMR is caused by donor-specific antibodies to HLA, which contribute to TAV by initiating outside-in signaling transduction pathways that elicit monocyte recruitment to activated endothelium. Mechanistic target of rapamycin (mTOR) inhibitors can attenuate TAV; therefore, we sought to understand the mechanistic underpinnings of mTOR signaling in HLA class I Ab-mediated endothelial cell activation and monocyte recruitment. We used an in vitro model to assess monocyte binding to HLA I Ab-activated endothelial cells and found mTOR inhibition reduced ezrin/radixin/moesin (ERM) phosphorylation, intercellular adhesion molecule 1 (ICAM-1) clustering, and monocyte firm adhesion to HLA I Ab-activated endothelium. Further, in a mouse model of AMR, in which C57BL/6. RAG1 -/- recipients of BALB/c cardiac allografts were passively transferred with donor-specific MHC I antibodies, mTOR inhibition significantly reduced vascular injury, ERM phosphorylation, and macrophage infiltration of the allograft. Taken together, these studies indicate mTOR inhibition suppresses ERM phosphorylation in endothelial cells, which impedes ICAM-1 clustering in response to HLA class I Ab and prevents macrophage infiltration into cardiac allografts. These findings indicate a novel therapeutic application for mTOR inhibitors to disrupt endothelial cell-monocyte interactions during AMR. © 2017 The American Society of Transplantation and the American Society of Transplant Surgeons.

  17. Agmatine produces antidepressant-like effects by activating AMPA receptors and mTOR signaling.

    Science.gov (United States)

    Neis, Vivian Binder; Moretti, Morgana; Bettio, Luis Eduardo B; Ribeiro, Camille M; Rosa, Priscila Batista; Gonçalves, Filipe Marques; Lopes, Mark William; Leal, Rodrigo Bainy; Rodrigues, Ana Lúcia S

    2016-06-01

    The activation of AMPA receptors and mTOR signaling has been reported as mechanisms underlying the antidepressant effects of fast-acting agents, specially the NMDA receptor antagonist ketamine. In the present study, oral administration of agmatine (0.1mg/kg), a neuromodulator that has been reported to modulate NMDA receptors, caused a significant reduction in the immobility time of mice submitted to the tail suspension test (TST), an effect prevented by the administration of DNQX (AMPA receptor antagonist, 2.5μg/site, i.c.v.), BDNF antibody (1μg/site, i.c.v.), K-252a (TrkB receptor antagonist, 1μg/site, i.c.v.), LY294002 (PI3K inhibitor, 10nmol/site, i.c.v.) or rapamycin (selective mTOR inhibitor, 0.2nmol/site, i.c.v.). Moreover, the administration of lithium chloride (non-selective GSK-3β inhibitor, 10mg/kg, p.o.) or AR-A014418 (selective GSK-3β inhibitor, 0.01μg/site, i.c.v.) in combination with a sub-effective dose of agmatine (0.0001mg/kg, p.o.) reduced the immobility time in the TST when compared with either drug alone. Furthermore, increased immunocontents of BDNF, PSD-95 and GluA1 were found in the prefrontal cortex of mice just 1h after agmatine administration. These results indicate that the antidepressant-like effect of agmatine in the TST may be dependent on the activation of AMPA and TrkB receptors, PI3K and mTOR signaling as well as inhibition of GSK-3β, and increase in synaptic proteins. The results contribute to elucidate the complex signaling pathways involved in the antidepressant effect of agmatine and reinforce the pivotal role of these molecular targets for antidepressant responses. Copyright © 2016 Elsevier B.V. and ECNP. All rights reserved.

  18. PARP-1 modulation of mTOR signaling in response to a DNA alkylating agent.

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    Chantal Ethier

    Full Text Available Poly(ADP-ribose polymerase-1 (PARP-1 is widely involved in cell death responses. Depending on the degree of injury and on cell type, PARP activation may lead to autophagy, apoptosis or necrosis. In HEK293 cells exposed to the alkylating agent N-methyl-N'-nitro-N'-nitrosoguanine (MNNG, we show that PARP-1 activation triggers a necrotic cell death response. The massive poly(ADP-ribose (PAR synthesis following PARP-1 activation leads to the modulation of mTORC1 pathway. Shortly after MNNG exposure, NAD⁺ and ATP levels decrease, while AMP levels drastically increase. We characterized at the molecular level the consequences of these altered nucleotide levels. First, AMP-activated protein kinase (AMPK is activated and the mTORC1 pathway is inhibited by the phosphorylation of Raptor, in an attempt to preserve cellular energy. Phosphorylation of the mTORC1 target S6 is decreased as well as the phosphorylation of the mTORC2 component Rictor on Thr1135. Finally, Akt phosphorylation on Ser473 is lost and then, cell death by necrosis occurs. Inhibition of PARP-1 with the potent PARP inhibitor AG14361 prevents all of these events. Moreover, the antioxidant N-acetyl-L-cysteine (NAC can also abrogate all the signaling events caused by MNNG exposure suggesting that reactive oxygen species (ROS production is involved in PARP-1 activation and modulation of mTOR signaling. In this study, we show that PARP-1 activation and PAR synthesis affect the energetic status of cells, inhibit the mTORC1 signaling pathway and possibly modulate the mTORC2 complex affecting cell fate. These results provide new evidence that cell death by necrosis is orchestrated by the balance between several signaling pathways, and that PARP-1 and PAR take part in these events.

  19. Nutrient-Deprived Retinal Progenitors Proliferate in Response to Hypoxia: Interaction of the HIF-1 and mTOR Pathway

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    Helena Khaliullina

    2016-05-01

    Full Text Available At a cellular level, nutrients are sensed by the mechanistic Target of Rapamycin (mTOR. The response of cells to hypoxia is regulated via action of the oxygen sensor Hypoxia-Inducible Factor 1 (HIF-1. During development, injury and disease, tissues might face conditions of both low nutrient supply and low oxygen, yet it is not clear how cells adapt to both nutrient restriction and hypoxia, or how mTOR and HIF-1 interact in such conditions. Here we explore this question in vivo with respect to cell proliferation using the ciliary marginal zone (CMZ of Xenopus. We found that both nutrient-deprivation and hypoxia cause retinal progenitors to decrease their proliferation, yet when nutrient-deprived progenitors are exposed to hypoxia there is an unexpected rise in cell proliferation. This increase, mediated by HIF-1 signalling, is dependent on glutaminolysis and reactivation of the mTOR pathway. We discuss how these findings in non-transformed tissue may also shed light on the ability of cancer cells in poorly vascularised solid tumours to proliferate.

  20. Identification of Palmitoleic Acid Controlled by mTOR Signaling as a Biomarker of Polymyositis

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    Geng Yin

    2017-01-01

    Full Text Available Polymyositis (PM is a chronic disease characterized by muscle pain, weakness, and increase in muscle-related enzymes, accompanied with inflammations in lymphocytes. However, it is not well understood how the molecular alternations in lymphocytes contribute to the development of polymyositis. The mechanistic target of rapamycin (mTOR signaling is the central regulator of metabolism and inflammation in mammalian cells. Based on previous studies, we proposed that mTOR signaling may control inflammatory reactions via lipid metabolism. In this study, we aim to figure out the role of mTOR signaling in the development of polymyositis and identify novel biomarkers for the detection and therapy of polymyositis. After screening and validation, we found that palmitoleic acid, a monounsaturated fatty acid, is highly regulated by mTOR signaling. Inhibition of mTORC1 activity decreases palmitoleic acid level. Moreover, mTORC1 regulates the level of palmitoleic acid by controlling its de novo synthesis. Importantly, increased palmitoleic acid has been proven to be a marker of polymyositis. Our work identifies palmitoleic acid in peripheral blood mononuclear cells (PBMC as a biomarker of polymyositis and offers new targets to the clinical therapy.

  1. Hypothalamic roles of mTOR complex I: Integration of nutrient and hormone signals to regulate energy homeostasis

    Science.gov (United States)

    Mammalian or mechanistic target of rapamycin (mTOR) senses nutrient, energy, and hormone signals to regulate metabolism and energy homeostasis. mTOR activity in the hypothalamus, which is associated with changes in energy status, plays a critical role in the regulation of food intake and body weight...

  2. Six1 induces protein synthesis signaling expression in duck myoblasts mainly via up-regulation of mTOR

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    Haohan Wang

    2016-03-01

    Full Text Available Abstract As a critical transcription factor, Six1 plays an important role in the regulation of myogenesis and muscle development. However, little is known about its regulatory mechanism associated with muscular protein synthesis. The objective of this study was to investigate the effects of overexpression ofSix1 on the expression of key protein metabolism-related genes in duck myoblasts. Through an experimental model where duck myoblasts were transfected with a pEGFP-duSix1 construct, we found that overexpression of duckSix1 could enhance cell proliferation activity and increase mRNA expression levels of key genes involved in the PI3K/Akt/mTOR signaling pathway, while the expression of FOXO1, MuRF1and MAFbx was not significantly altered, indicating thatSix1 could promote protein synthesis in myoblasts through up-regulating the expression of several related genes. Additionally, in duck myoblasts treated with LY294002 and rapamycin, the specific inhibitors ofPI3K and mTOR, respectively, the overexpression of Six1 could significantly ameliorate inhibitive effects of these inhibitors on protein synthesis. Especially, the mRNA expression levels of mTOR and S6K1 were observed to undergo a visible change, and a significant increase in protein expression of S6K1 was seen. These data suggested that Six1plays an important role in protein synthesis, which may be mainly due to activation of the mTOR signaling pathway.

  3. Bifenthrin causes transcriptomic alterations in mTOR and ryanodine receptor-dependent signaling and delayed hyperactivity in developing zebrafish (Danio rerio).

    Science.gov (United States)

    Frank, Daniel F; Miller, Galen W; Harvey, Danielle J; Brander, Susanne M; Geist, Juergen; Connon, Richard E; Lein, Pamela J

    2018-04-18

    Over the last few decades, the pyrethroid insecticide bifenthrin has been increasingly employed for pest control in urban and agricultural areas, putting humans and wildlife at increased risk of exposure. Exposures to nanomolar (nM) concentrations of bifenthrin have recently been reported to alter calcium oscillations in rodent neurons. Neuronal calcium oscillations are influenced by ryanodine receptor (RyR) activity, which modulates calcium-dependent signaling cascades, including the mechanistic target of rapamycin (mTOR) signaling pathway. RyR activity and mTOR signaling play critical roles in regulating neurodevelopmental processes. However, whether environmentally relevant levels of bifenthrin alter RyR or mTOR signaling pathways to influence neurodevelopment has not been addressed. Therefore, our main objectives in this study were to examine the transcriptomic responses of genes involved in RyR and mTOR signaling pathways in zebrafish (Danio rerio) exposed to low (ng/L) concentrations of bifenthrin, and to assess the potential functional consequences by measuring locomotor responses to external stimuli. Wildtype zebrafish were exposed for 1, 3 and 5 days to 1, 10 and 50 ng/L bifenthrin, followed by a 14 d recovery period. Bifenthrin elicited significant concentration-dependent transcriptional responses in the majority of genes examined in both signaling cascades, and at all time points examined during the acute exposure period (1, 3, and 5 days post fertilization; dpf), and at the post recovery assessment time point (19 dpf). Changes in locomotor behavior were not evident during the acute exposure period, but were observed at 19 dpf, with main effects (increased locomotor behavior) detected in fish exposed developmentally to bifenthrin at 1 or 10 ng/L, but not 50 ng/L. These findings illustrate significant influences of developmental exposures to low (ng/L) concentrations of bifenthrin on neurodevelopmental processes in zebrafish. Copyright © 2018

  4. Advanced Research of mTOR and Lung Carcinoid Tumors

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    Zixuan ZHANG

    2013-01-01

    Full Text Available Mammalian target of rapamycin (mTOR, a main protein kinase in the phosphoinositide 3-kinase (PI3K/AKT/mTOR signaling pathway, is an important intracellular mediator involved in multiple celluar functions including proliferation, differentiation, apoptosis, tumorigenesis, and angiogenesis. Recently, the high expression of mTOR and mTOR-related kinase have been found in neuroendocrin tumors. Therefore, mTOR pathway represents an attractive target for new anticancer therapies except surgery.

  5. The Effects of Krill Oil on mTOR Signaling and Resistance Exercise: A Pilot Study

    OpenAIRE

    Georges, John; Sharp, Matthew H.; Lowery, Ryan P.; Wilson, Jacob M.; Purpura, Martin; Hornberger, Troy A.; Harding, Flint; Johnson, James H.; Peele, David M.; Jäger, Ralf

    2018-01-01

    Introduction. Krill oil supplementation has been shown to improve postexercise immune function; however, its effect on muscle hypertrophy is currently unknown. Therefore, the aim of present study was to investigate the ability of krill oil to stimulate mTOR signaling and its ability to augment resistance training-induced changes in body composition and performance. Methods. C2C12 myoblasts cells were stimulated with krill oil or soy-derived phosphatidylcholine (S-PC), and then, the ratio of P...

  6. The Effects of Krill Oil on mTOR Signaling and Resistance Exercise: A Pilot Study

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    John Georges

    2018-01-01

    Full Text Available Introduction. Krill oil supplementation has been shown to improve postexercise immune function; however, its effect on muscle hypertrophy is currently unknown. Therefore, the aim of present study was to investigate the ability of krill oil to stimulate mTOR signaling and its ability to augment resistance training-induced changes in body composition and performance. Methods. C2C12 myoblasts cells were stimulated with krill oil or soy-derived phosphatidylcholine (S-PC, and then, the ratio of P-p70-389 to total p70 was used as readout for mTOR signaling. In double-blind,placebo-controlled study, resistance trained subjects consumed either 3 g krill oil daily or placebo, and each took part in an 8-week periodized resistance training program. Body composition, maximal strength, peak power, and rate of perceived recovery were assessed collectively at the end of weeks 0 and 8. In addition, safety parameters (comprehensive metabolic panel (CMP, complete blood count (CBC, and urine analysis (UA and cognitive performance were measured pre- and posttesting. Results. Krill oil significantly stimulated mTOR signaling in comparison to S-PC and control. No differences for markers on the CMP, CBC, or UA were observed. Krill oil significantly increased lean body mass from baseline (p=0.021, 1.4 kg, +2.1%; however, there were no statistically significant differences between groups for any measures taken. Conclusion. Krill oil activates mTOR signaling. Krill oil supplementation in athletes is safe, and its effect on resistance exercise deserves further research.

  7. Thyroid hormone-dependent development of early cortical networks: Temporal specificity and the contribution of trkB and mTOR pathways

    Directory of Open Access Journals (Sweden)

    Sören eWesterholz

    2013-08-01

    Full Text Available Early in neocortical network development, triiodothyronine (T3 promotes GABAergic neurons’ population increase, their somatic growth and the formation of GABAergic synapses. In the presence of T3, GABAergic interneurons form longer axons and conspicuous axonal arborizations, with an increased number of putative synaptic boutons. Here we show that the increased GABAergic axonal growth is positively correlated with the proximity to non-GABAergic neurons. A differential innervation emerges from a T3-dependent decrease of axonal length in fields with low density of neuronal cell bodies, combined with an increased bouton formation in fields with high density of neuronal somata. T3 addition to deprived networks after the first two weeks of development did not rescue deficits in the GABAergic synaptic bouton distribution, or in the frequency and duration of spontaneous bursts. During the critical two-week-period, GABAergic signaling is depolarizing as revealed by calcium imaging experiments. Interestingly, T3 enhanced the expression of the potassium-chloride cotransporter 2 (KCC2, and accelerated the developmental shift from depolarizing to hyperpolarizing GABAergic signaling in non-GABAergic neurons.The T3-related increase of spontaneous network activity was remarkably reduced after blockade of either tropomyosin-receptor kinase B (trkB or mammalian target of rapamycin (mTOR pathways. T3-dependent increase in GABAergic neurons’ soma size was mediated mainly by mTOR signaling. Conversely, the T3-dependent selective increase of GABAergic boutons near non-GABAergic cell bodies is mediated by trkB signaling only. Both trkB and mTOR signaling mediate T3-dependent reduction of the GABAergic axon extension. The circuitry context is relevant for the interaction between T3 and trkB signaling, but not for the interactions between T3 and mTOR signaling.

  8. Alcohol Inhibits Odontogenic Differentiation of Human Dental Pulp Cells by Activating mTOR Signaling

    Directory of Open Access Journals (Sweden)

    Wei Qin

    2017-01-01

    Full Text Available Long-term heavy alcohol consumption could result in a range of health, social, and behavioral problems. People who abuse alcohol are at high risks of seriously having osteopenia, periodontal disease, and compromised oral health. However, the role of ethanol (EtOH in the biological functions of human dental pulp cells (DPCs is unknown. Whether EtOH affects the odontoblastic differentiation of DPCs through the mechanistic target of rapamycin (mTOR remains unexplored. The objective of this study was to investigate the effects of EtOH on DPC differentiation and mineralization. DPCs were isolated and purified from human dental pulps. The proliferation and odontoblastic differentiation of DPCs treated with EtOH were subsequently investigated. Different doses of EtOH were shown to be cytocompatible with DPCs. EtOH significantly activated the mTOR pathway in a dose-dependent manner. In addition, EtOH downregulated the alkaline phosphatase activity, attenuated the mineralized nodule formation, and suppressed the expression of odontoblastic markers including ALP, DSPP, DMP-1, Runx2, and OCN. Moreover, the pretreatment with rapamycin, a specific mTOR inhibitor, markedly reversed the EtOH-induced odontoblastic differentiation and cell mineralization. Our findings show for the first time that EtOH can suppress DPC differentiation and mineralization in a mTOR-dependent manner, indicating that EtOH may be involved in negatively regulating the dental pulp repair.

  9. Alcohol Inhibits Odontogenic Differentiation of Human Dental Pulp Cells by Activating mTOR Signaling.

    Science.gov (United States)

    Qin, Wei; Huang, Qi-Ting; Weir, Michael D; Song, Zhi; Fouad, Ashraf F; Lin, Zheng-Mei; Zhao, Liang; Xu, Hockin H K

    2017-01-01

    Long-term heavy alcohol consumption could result in a range of health, social, and behavioral problems. People who abuse alcohol are at high risks of seriously having osteopenia, periodontal disease, and compromised oral health. However, the role of ethanol (EtOH) in the biological functions of human dental pulp cells (DPCs) is unknown. Whether EtOH affects the odontoblastic differentiation of DPCs through the mechanistic target of rapamycin (mTOR) remains unexplored. The objective of this study was to investigate the effects of EtOH on DPC differentiation and mineralization. DPCs were isolated and purified from human dental pulps. The proliferation and odontoblastic differentiation of DPCs treated with EtOH were subsequently investigated. Different doses of EtOH were shown to be cytocompatible with DPCs. EtOH significantly activated the mTOR pathway in a dose-dependent manner. In addition, EtOH downregulated the alkaline phosphatase activity, attenuated the mineralized nodule formation, and suppressed the expression of odontoblastic markers including ALP, DSPP, DMP-1, Runx2, and OCN. Moreover, the pretreatment with rapamycin, a specific mTOR inhibitor, markedly reversed the EtOH-induced odontoblastic differentiation and cell mineralization. Our findings show for the first time that EtOH can suppress DPC differentiation and mineralization in a mTOR-dependent manner, indicating that EtOH may be involved in negatively regulating the dental pulp repair.

  10. The role of mTOR signaling in the regulation of protein synthesis and muscle mass during immobilization in mice

    Science.gov (United States)

    You, Jae-Sung; Anderson, Garrett B.; Dooley, Matthew S.; Hornberger, Troy A.

    2015-01-01

    ABSTRACT The maintenance of skeletal muscle mass contributes substantially to health and to issues associated with the quality of life. It has been well recognized that skeletal muscle mass is regulated by mechanically induced changes in protein synthesis, and that signaling by mTOR is necessary for an increase in protein synthesis and the hypertrophy that occurs in response to increased mechanical loading. However, the role of mTOR signaling in the regulation of protein synthesis and muscle mass during decreased mechanical loading remains largely undefined. In order to define the role of mTOR signaling, we employed a mouse model of hindlimb immobilization along with pharmacological, mechanical and genetic means to modulate mTOR signaling. The results first showed that immobilization induced a decrease in the global rates of protein synthesis and muscle mass. Interestingly, immobilization also induced an increase in mTOR signaling, eIF4F complex formation and cap-dependent translation. Blocking mTOR signaling during immobilization with rapamycin not only impaired the increase in eIF4F complex formation, but also augmented the decreases in global protein synthesis and muscle mass. On the other hand, stimulating immobilized muscles with isometric contractions enhanced mTOR signaling and rescued the immobilization-induced decrease in global protein synthesis through a rapamycin-sensitive mechanism that was independent of ribosome biogenesis. Unexpectedly, the effects of isometric contractions were also independent of eIF4F complex formation. Similar to isometric contractions, overexpression of Rheb in immobilized muscles enhanced mTOR signaling, cap-dependent translation and global protein synthesis, and prevented the reduction in fiber size. Therefore, we conclude that the activation of mTOR signaling is both necessary and sufficient to alleviate the decreases in protein synthesis and muscle mass that occur during immobilization. Furthermore, these results indicate

  11. MenTORing Immunity: mTOR Signaling in the Development and Function of Tissue-Resident Immune Cells.

    Science.gov (United States)

    Jones, Russell G; Pearce, Edward J

    2017-05-16

    Tissue-resident immune cells must balance survival in peripheral tissues with the capacity to respond rapidly upon infection or tissue damage, and in turn couple these responses with intrinsic metabolic control and conditions in the tissue microenvironment. The serine/threonine kinase mammalian/mechanistic target of rapamycin (mTOR) is a central integrator of extracellular and intracellular growth signals and cellular metabolism and plays important roles in both innate and adaptive immune responses. This review discusses the function of mTOR signaling in the differentiation and function of tissue-resident immune cells, with focus on the role of mTOR as a metabolic sensor and its impact on metabolic regulation in innate and adaptive immune cells. We also discuss the impact of metabolic constraints in tissues on immune homeostasis and disease, and how manipulating mTOR activity with drugs such as rapamycin can modulate immunity in these contexts. Copyright © 2017. Published by Elsevier Inc.

  12. Deregulation of mTOR signaling is involved in thymic lymphoma development in Atm-/- mice

    International Nuclear Information System (INIS)

    Kuang, Xianghong; Shen, Jianjun; Wong, Paul K.Y.; Yan, Mingshan

    2009-01-01

    Abnormal thymocyte development with thymic lymphomagenesis inevitably occurs in Atm-/- mice, indicating that ATM plays a pivotal role in regulating postnatal thymocyte development and preventing thymic lymphomagenesis. The mechanism for ATM controls these processes is unclear. We have shown previously that c-Myc, an oncoprotein regulated by the mammalian target of rapamycin (mTOR), is overexpressed in Atm-/- thymocytes. Here, we show that inhibition of mTOR signaling with its specific inhibitor, rapamycin, suppresses normal thymocyte DNA synthesis by downregulating 4EBP1, but not S6K, and that 4EBP1 phosphorylation and cyclin D1 expression are coordinately increased in Atm-/- thymocytes. Administration of rapamycin to Atm-/- mice attenuates elevated phospho-4EBP1, c-Myc and cyclin D1 in their thymocytes, and delays thymic lymphoma development. These results indicate that mTOR downstream effector 4EBP1 is essential for normal thymocyte proliferation, but deregulation of 4EBP1 in Atm deficiency is a major factor driving thymic lymphomagenesis in the animals.

  13. Comment on "A dynamic network model of mTOR signaling reveals TSC-independent mTORC2 regulation": building a model of the mTOR signaling network with a potentially faulty tool.

    Science.gov (United States)

    Manning, Brendan D

    2012-07-10

    In their study published in Science Signaling (Research Article, 27 March 2012, DOI: 10.1126/scisignal.2002469), Dalle Pezze et al. tackle the dynamic and complex wiring of the signaling network involving the protein kinase mTOR, which exists within two distinct protein complexes (mTORC1 and mTORC2) that differ in their regulation and function. The authors use a combination of immunoblotting for specific phosphorylation events and computational modeling. The primary experimental tool employed is to monitor the autophosphorylation of mTOR on Ser(2481) in cell lysates as a surrogate for mTOR activity, which the authors conclude is a specific readout for mTORC2. However, Ser(2481) phosphorylation occurs on both mTORC1 and mTORC2 and will dynamically change as the network through which these two complexes are connected is manipulated. Therefore, models of mTOR network regulation built using this tool are inherently imperfect and open to alternative explanations. Specific issues with the main conclusion made in this study, involving the TSC1-TSC2 (tuberous sclerosis complex 1 and 2) complex and its potential regulation of mTORC2, are discussed here. A broader goal of this Letter is to clarify to other investigators the caveats of using mTOR Ser(2481) phosphorylation in cell lysates as a specific readout for either of the two mTOR complexes.

  14. 25-Hydroxycholecalciferol Enhances Male Broiler Breast Meat Yield through the mTOR Pathway.

    Science.gov (United States)

    Vignale, Karen; Greene, Elizabeth S; Caldas, Justina V; England, Judith A; Boonsinchai, Nirun; Sodsee, Phiphob; Pollock, Erik D; Dridi, Sami; Coon, Craig N

    2015-05-01

    In recent years, there has been a growing body of evidence indicating that replacing cholecalciferol (vitamin D₃) with 25-hydroxycholecalciferol [25(OH)D₃] through dietary supplementation enhances breast meat yield in broiler chickens. However, the underlying molecular mechanisms are still unknown. We investigated the effect of 25(OH)D₃ on male broiler growth performance (body weight, feed intake, feed conversion ratio, and breast meat yield), muscle protein synthesis, and the potential underlying molecular mechanisms. Male Cobb 500 broiler chickens were divided into 4 body weight-matched groups and received a control diet with normal cholecalciferol (2760 IU/kg feed) for 42 d, a diet with high concentrations of cholecalciferol (5520 IU/kg feed) for 42 d, or a diet with 25(OH)D₃ (5520 IU/kg feed) for 42 d (HyD-42). A fourth group consumed the HyD-42 for 21 d and then control feed for 21 d (HyD-21) (n = 360 birds, 12 replicates/treatment). Food and clean water were available for ad libitum consumption. At the end of the 42-d experiment, protein turnover was measured by phenylalanine flooding dose. Breast muscle tissues were collected and protein synthesis-related gene and protein expression were measured by real time polymerase chain reaction and Western blot, respectively. Functional studies were performed in vitro with the use of a quail myoblast (QM7) cell line. QM7 cells were treated with 2 doses (1 nM and 10 nM) of cholecalciferol or 25(OH)D₃ alone or in combination with 100 nM rapamycin, and cell proliferation was determined by cell proliferation assay. Protein synthesis-related gene and protein expression were also determined. The HyD-42 increased 25(OH)D₃ circulating concentrations by 126% (P meat yield (P vitro functional studies showed that cells treated with 25(OH)D₃ for 24 h had increased VDR expression, and activated the mechanistic target of rapamycin (mTOR)/S6 kinase (S6K) pathway, enhanced Ki67 protein concentrations, and induced QM7

  15. mTOR dysregulation and tuberous sclerosis-related epilepsy

    NARCIS (Netherlands)

    Curatolo, Paolo; Moavero, Romina; van Scheppingen, Jackelien; Aronica, Eleonora

    2018-01-01

    The mammalian target of rapamycin (mTOR) pathway has emerged as a key player for proper neural network development, and it is involved in epileptogenesis triggered by both genetic or acquired factors. Areas covered. The robust mTOR signaling deregulation observed in a large spectrum of epileptogenic

  16. PRKCI negatively regulates autophagy via PIK3CA/AKT–MTOR signaling

    Energy Technology Data Exchange (ETDEWEB)

    Qu, Liujing; Li, Ge; Xia, Dan; Hongdu, Beiqi; Xu, Chentong; Lin, Xin [Key Laboratory of Medical Immunology, Ministry of Health, Peking University Health Sciences Center, Beijing (China); Peking University Center for Human Disease Genomics, Peking University, Beijing (China); Chen, Yingyu, E-mail: yingyu_chen@bjmu.edu.cn [Key Laboratory of Medical Immunology, Ministry of Health, Peking University Health Sciences Center, Beijing (China); Peking University Center for Human Disease Genomics, Peking University, Beijing (China)

    2016-02-05

    The atypical protein kinase C isoform PRKC iota (PRKCI) plays a key role in cell proliferation, differentiation, and carcinogenesis, and it has been shown to be a human oncogene. Here, we show that PRKCI overexpression in U2OS cells impaired functional autophagy in normal or cell stress conditions, as characterized by decreased levels of light chain 3B-II protein (LC3B-II) and weakened degradation of endogenous and exogenous autophagic substrates. Conversely, PRKCI knockdown by small interference RNA resulted in opposite effects. Additionally, we identified two novel PRKCI mutants, PRKCI{sup L485M} and PRKCI{sup P560R}, which induced autophagy and exhibited dominant negative effects. Further studies indicated that PRKCI knockdown–mediated autophagy was associated with the inactivation of phosphatidylinositol 3-kinase alpha/AKT–mammalian target of rapamycin (PIK3CA/AKT–MTOR) signaling. These data underscore the importance of PRKCI in the regulation of autophagy. Moreover, the finding may be useful in treating PRKCI-overexpressing carcinomas that are characterized by increased levels of autophagy. - Highlights: • The atypical protein kinase C iota isoform (PRKCI) is a human oncogene. • PRKCI overexpression impairs functional autophagy in U2OS cells. • It reduces LC3B-II levels and weakens SQSTM1 and polyQ80 aggregate degradation. • PRKCI knockdown has the opposite effect. • The effect of PRKCI knockdown is related to PIK3CA/AKT–MTOR signaling inactivation.

  17. A Recollection of mTOR Signaling in Learning and Memory

    Science.gov (United States)

    Graber, Tyson E.; McCamphill, Patrick K.; Sossin, Wayne S.

    2013-01-01

    Mechanistic target of rapamcyin (mTOR) is a central player in cell growth throughout the organism. However, mTOR takes on an additional, more specialized role in the developed neuron, where it regulates the protein synthesis-dependent, plastic changes underlying learning and memory. mTOR is sequestered in two multiprotein complexes (mTORC1 and…

  18. Caffeine affects the biological responses of human hematopoietic cells of myeloid lineage via downregulation of the mTOR pathway and xanthine oxidase activity

    Science.gov (United States)

    Abooali, Maryam; Yasinska, Inna M.; Casely-Hayford, Maxwell A.; Berger, Steffen M.; Fasler-Kan, Elizaveta; Sumbayev, Vadim V.

    2015-01-01

    Correction of human myeloid cell function is crucial for the prevention of inflammatory and allergic reactions as well as leukaemia progression. Caffeine, a naturally occurring food component, is known to display anti-inflammatory effects which have previously been ascribed largely to its inhibitory actions on phosphodiesterase. However, more recent studies suggest an additional role in affecting the activity of the mammalian target of rapamycin (mTOR), a master regulator of myeloid cell translational pathways, although detailed molecular events underlying its mode of action have not been elucidated. Here, we report the cellular uptake of caffeine, without metabolisation, by healthy and malignant hematopoietic myeloid cells including monocytes, basophils and primary acute myeloid leukaemia mononuclear blasts. Unmodified caffeine downregulated mTOR signalling, which affected glycolysis and the release of pro-inflammatory/pro-angiogenic cytokines as well as other inflammatory mediators. In monocytes, the effects of caffeine were potentiated by its ability to inhibit xanthine oxidase, an enzyme which plays a central role in human purine catabolism by generating uric acid. In basophils, caffeine also increased intracellular cyclic adenosine monophosphate (cAMP) levels which further enhanced its inhibitory action on mTOR. These results demonstrate an important mode of pharmacological action of caffeine with potentially wide-ranging therapeutic impact for treating non-infectious disorders of the human immune system, where it could be applied directly to inflammatory cells. PMID:26384306

  19. Association of breast cancer risk and the mTOR pathway in women of African ancestry in 'The Root' Consortium.

    Science.gov (United States)

    Wang, Shengfeng; Huo, Dezheng; Ogundiran, Temidayo O; Ojengbede, Oladosu; Zheng, Wei; Nathanson, Katherine L; Nemesure, Barbara; Ambs, Stefan; Olopade, Olufunmilayo I; Zheng, Yonglan

    2017-08-01

    Functional studies have elucidated the role of the mammalian target of rapamycin (mTOR) pathway in breast carcinogenesis, but to date, there is a paucity of data on its contribution to breast cancer risk in women of African ancestry. We examined 47628 SNPs in 61 mTOR pathway genes in the genome wide association study of breast cancer in the African Diaspora study (The Root consortium), which included 3686 participants (1657 cases). Pathway- and gene-level analyses were conducted using the adaptive rank truncated product (ARTP) test for 10994 SNPs that were not highly correlated (r2 studies of breast cancer in the African Diaspora. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  20. Critical nodes in signalling pathways

    DEFF Research Database (Denmark)

    Taniguchi, Cullen M; Emanuelli, Brice; Kahn, C Ronald

    2006-01-01

    Physiologically important cell-signalling networks are complex, and contain several points of regulation, signal divergence and crosstalk with other signalling cascades. Here, we use the concept of 'critical nodes' to define the important junctions in these pathways and illustrate their unique role...... using insulin signalling as a model system....

  1. Phosphatidylinositol-3-OH kinase and nutrient-sensing mTOR pathways control T lymphocyte trafficking

    NARCIS (Netherlands)

    Sinclair, Linda V.; Finlay, David; Feijoo, Carmen; Cornish, Georgina H.; Gray, Alex; Ager, Ann; Okkenhaug, Klaus; Hagenbeek, Thijs J.; Spits, Hergen; Cantrell, Doreen A.

    2008-01-01

    Phosphatidylinositol-3-OH kinase (PI(3)K) and the nutrient sensor mTOR are evolutionarily conserved regulators of cell metabolism. Here we show that PI(3)K and mTOR determined the repertoire of adhesion and chemokine receptors expressed by T lymphocytes. The key lymph node-homing receptors CD62L

  2. Activation of mTor Signaling by Gene Transduction to Induce Axon Regeneration in the Central Nervous System Following Neural Injury (Addendum)

    Science.gov (United States)

    2016-03-01

    terminus amino acids of amyloid precursor protein (cAPP). cAPP had been found in our publication in Gene Therapy (2013) to be the most effective known axon...Efeyan A, Sabatini DM. mTOR: from growth signal integration to cancer, diabetes and ageing. NatRevMolCell Biol. 2011;12:21-35. 8. Morita T, Sobue K...Specification of neuronal polarity regulated by local translation of CRMP2 and Tau via the mTOR-p70S6K pathway. JBiolChem. 2009;284:27734-45. 9. Yan

  3. The actions of exogenous leucine on mTOR signalling and amino acid transporters in human myotubes

    Directory of Open Access Journals (Sweden)

    Cameron-Smith David

    2011-06-01

    Full Text Available Abstract Background The branched-chain amino acid (BCAA leucine has been identified to be a key regulator of skeletal muscle anabolism. Activation of anabolic signalling occurs via the mammalian target of rapamycin (mTOR through an undefined mechanism. System A and L solute carriers transport essential amino acids across plasma membranes; however it remains unknown whether an exogenous supply of leucine regulates their gene expression. The aim of the present study was to investigate the effects of acute and chronic leucine stimulation of anabolic signalling and specific amino acid transporters, using cultured primary human skeletal muscle cells. Results Human myotubes were treated with leucine, insulin or co-treated with leucine and insulin for 30 min, 3 h or 24 h. Activation of mTOR signalling kinases were examined, together with putative nutrient sensor human vacuolar protein sorting 34 (hVps34 and gene expression of selected amino acid transporters. Phosphorylation of mTOR and p70S6K was transiently increased following leucine exposure, independently to insulin. hVps34 protein expression was also significantly increased. However, genes encoding amino acid transporters were differentially regulated by insulin and not leucine. Conclusions mTOR signalling is transiently activated by leucine within human myotubes independently of insulin stimulation. While this occurred in the absence of changes in gene expression of amino acid transporters, protein expression of hVps34 increased.

  4. Non-Smad signaling pathways.

    Science.gov (United States)

    Mu, Yabing; Gudey, Shyam Kumar; Landström, Maréne

    2012-01-01

    Transforming growth factor-beta (TGFβ) is a key regulator of cell fate during embryogenesis and has also emerged as a potent driver of the epithelial-mesenchymal transition during tumor progression. TGFβ signals are transduced by transmembrane type I and type II serine/threonine kinase receptors (TβRI and TβRII, respectively). The activated TβR complex phosphorylates Smad2 and Smad3, converting them into transcriptional regulators that complex with Smad4. TGFβ also uses non-Smad signaling pathways such as the p38 and Jun N-terminal kinase (JNK) mitogen-activated protein kinase (MAPK) pathways to convey its signals. Ubiquitin ligase tumor necrosis factor (TNF)-receptor-associated factor 6 (TRAF6) and TGFβ-associated kinase 1 (TAK1) have recently been shown to be crucial for the activation of the p38 and JNK MAPK pathways. Other TGFβ-induced non-Smad signaling pathways include the phosphoinositide 3-kinase-Akt-mTOR pathway, the small GTPases Rho, Rac, and Cdc42, and the Ras-Erk-MAPK pathway. Signals induced by TGFβ are tightly regulated and specified by post-translational modifications of the signaling components, since they dictate the subcellular localization, activity, and duration of the signal. In this review, we discuss recent findings in the field of TGFβ-induced responses by non-Smad signaling pathways.

  5. Hypothalamic roles of mTOR complex I: integration of nutrient and hormone signals to regulate energy homeostasis.

    Science.gov (United States)

    Hu, Fang; Xu, Yong; Liu, Feng

    2016-06-01

    Mammalian or mechanistic target of rapamycin (mTOR) senses nutrient, energy, and hormone signals to regulate metabolism and energy homeostasis. mTOR activity in the hypothalamus, which is associated with changes in energy status, plays a critical role in the regulation of food intake and body weight. mTOR integrates signals from a variety of "energy balancing" hormones such as leptin, insulin, and ghrelin, although its action varies in response to these distinct hormonal stimuli as well as across different neuronal populations. In this review, we summarize and highlight recent findings regarding the functional roles of mTOR complex 1 (mTORC1) in the hypothalamus specifically in its regulation of body weight, energy expenditure, and glucose/lipid homeostasis. Understanding the role and underlying mechanisms behind mTOR-related signaling in the brain will undoubtedly pave new avenues for future therapeutics and interventions that can combat obesity, insulin resistance, and diabetes. Copyright © 2016 the American Physiological Society.

  6. The Inhibition of microRNA-128 on IGF-1-Activating mTOR Signaling Involves in Temozolomide-Induced Glioma Cell Apoptotic Death.

    Directory of Open Access Journals (Sweden)

    Peng-Hsu Chen

    Full Text Available Temozolomide (TMZ, an alkylating agent of the imidazotetrazine series, is a first-line chemotherapeutic drug used in the clinical therapy of glioblastoma multiforme, the most common and high-grade primary glioma in adults. Micro (miRNAs, which are small noncoding RNAs, post-transcriptionally regulate gene expressions and are involved in gliomagenesis. However, no studies have reported relationships between TMZ and miRNA gene regulation. We investigated TMZ-mediated miRNA profiles and its molecular mechanisms underlying the induction of glioma cell death. By performing miRNA microarray and bioinformatics analyses, we observed that expression of 248 miRNAs was altered, including five significantly upregulated and 17 significantly downregulated miRNAs, in TMZ-treated U87MG cells. miR-128 expression levels were lower in different glioma cells and strongly associated with poor survival. TMZ treatment significantly upregulated miR-128 expression. TMZ significantly enhanced miR-128-1 promoter activity and transcriptionally regulated miR-128 levels through c-Jun N-terminal kinase 2/c-Jun pathways. The overexpression and knockdown of miR-128 expression significantly affected TMZ-mediated cell viability and apoptosis-related protein expression. Furthermore, the overexpression of miR-128 alone enhanced apoptotic death of glioma cells through caspase-3/9 activation, poly(ADP ribose polymerase degradation, reactive oxygen species generation, mitochondrial membrane potential loss, and non-protective autophagy formation. Finally, we identified that key members in mammalian target of rapamycin (mTOR signaling including mTOR, rapamycin-insensitive companion of mTOR, insulin-like growth factor 1, and PIK3R1, but not PDK1, were direct target genes of miR-128. TMZ inhibited mTOR signaling through miR-128 regulation. These results indicate that miR-128-inhibited mTOR signaling is involved in TMZ-mediated cytotoxicity. Our findings may provide a better understanding

  7. Regulation of the mTOR Pathway by a Novel Rheb Binding Protein BNIP3

    National Research Council Canada - National Science Library

    Guan, Kun-Liang

    2008-01-01

    .... We demonstrate that BNIP3 plays a critical role in hypoxia-induced mTOR inhibition. Furthermore we found that BNIP3 itself has a growth inhibitory activity and inactivation of BNIP3 promotes cell growth...

  8. Retroactive signaling in short signaling pathways.

    Directory of Open Access Journals (Sweden)

    Jacques-Alexandre Sepulchre

    Full Text Available In biochemical signaling pathways without explicit feedback connections, the core signal transduction is usually described as a one-way communication, going from upstream to downstream in a feedforward chain or network of covalent modification cycles. In this paper we explore the possibility of a new type of signaling called retroactive signaling, offered by the recently demonstrated property of retroactivity in signaling cascades. The possibility of retroactive signaling is analysed in the simplest case of the stationary states of a bicyclic cascade of signaling cycles. In this case, we work out the conditions for which variables of the upstream cycle are affected by a change of the total amount of protein in the downstream cycle, or by a variation of the phosphatase deactivating the same protein. Particularly, we predict the characteristic ranges of the downstream protein, or of the downstream phosphatase, for which a retroactive effect can be observed on the upstream cycle variables. Next, we extend the possibility of retroactive signaling in short but nonlinear signaling pathways involving a few covalent modification cycles.

  9. The role of mTOR in ovarian cancer, polycystic ovary syndrome and ovarian aging.

    Science.gov (United States)

    Liu, Jin; Wu, Dai-Chao; Qu, Li-Hua; Liao, Hong-Qing; Li, Mei-Xiang

    2018-05-12

    The mammalian target of rapamycin, mTOR, is a serine-threonine protein kinase downstream of the phosphatidylinositol 3-kinase (PI3K)-AKT axis. The pathway can regulate cell growth, proliferation, and survival by activating ribosomal kinases. Recent studies have implicated the mTOR signaling pathway in ovarian neoplasms, polycystic ovary syndrome (PCOS) and premature ovarian failure (POF). Preclinical investigations have demonstrated that the PI3K/AKT/mTOR pathway is frequently activated in the control of various ovarian functions. mTOR allows cancer cells to escape the normal biochemical system and regulates the balance between apoptosis and survival. Some recent studies have suggested that involvement of the mTOR signaling system is an important pathophysiological basis of PCOS. Overexpression of the mTOR pathway can impair the interaction of cumulus cells, lead to insulin resistance, and affect the growth of follicles directly. The roles of mTOR signaling in follicular development have been extensively studied in recent years; abnormalities in this process lead to a series of pathologies such as POF and infertility. To improve understanding of the role of the mTOR signaling pathway in the pathogenesis and development of ovarian diseases, here we review the roles of mTOR signaling in such diseases and discuss the corresponding therapeutic strategies that target this pathway. This article is protected by copyright. All rights reserved. © 2018 Wiley Periodicals, Inc.

  10. Aberrant Signaling Pathways in Glioma

    International Nuclear Information System (INIS)

    Nakada, Mitsutoshi; Kita, Daisuke; Watanabe, Takuya; Hayashi, Yutaka; Teng, Lei; Pyko, Ilya V.; Hamada, Jun-Ichiro

    2011-01-01

    Glioblastoma multiforme (GBM), a WHO grade IV malignant glioma, is the most common and lethal primary brain tumor in adults; few treatments are available. Median survival rates range from 12–15 months. The biological characteristics of this tumor are exemplified by prominent proliferation, active invasiveness, and rich angiogenesis. This is mainly due to highly deregulated signaling pathways in the tumor. Studies of these signaling pathways have greatly increased our understanding of the biology and clinical behavior of GBM. An integrated view of signal transduction will provide a more useful approach in designing novel therapies for this devastating disease. In this review, we summarize the current understanding of GBM signaling pathways with a focus on potential molecular targets for anti-signaling molecular therapies

  11. DUAL INHIBITION OF PI3K/AKT AND mTOR SIGNALING IN HUMAN NON-SMALL CELL LUNG CANCER CELLS BY A DIETARY FLAVONOID FISETIN

    Science.gov (United States)

    Khan, Naghma; Afaq, Farrukh; Khusro, Fatima H.; Adhami, Vaqar Mustafa; Suh, Yewseok; Mukhtar, Hasan

    2011-01-01

    Lung cancer is one of the most commonly occurring malignancies. It has been reported that mTOR is phosphorylated in lung cancer and its activation was more frequent in tumors with over-expression of PI3K/Akt. Therefore, dual inhibitors of PI3K/Akt and mTOR signaling could be valuable agents for treating lung cancer. In the present study, we show that fisetin, a dietary tetrahydroxyflavone inhibits cell-growth with the concomitant suppression of PI3K/Akt and mTOR signaling in human non-small cell lung cancer (NSCLC) cells. Using autodock 4, we found that fisetin physically interacts with the mTOR complex at two sites. Fisetin treatment was also found to reduce the formation of A549 cell colonies in a dose-dependent manner. Treatment of cells with fisetin caused decrease in the protein expression of PI3K (p85 and p110), inhibition of phosphorylation of Akt, mTOR, p70S6K1, eIF-4E and 4E-BP1. Fisetin-treated cells also exhibited dose-dependent inhibition of the constituents of mTOR signaling complex like Rictor, Raptor, GβL and PRAS40. There was increase in the phosphorylation of AMPKα and decrease in the phosphorylation of TSC2 on treatment of cells with fisetin. We also found that treatment of cells with mTOR inhibitor rapamycin and mTOR-siRNA caused decrease in phosphorylation of mTOR and its target proteins which were further downregulated on treatment with fisetin, suggesting that these effects are mediated in part, through mTOR signaling. Our results show that fisetin suppressed PI3K/Akt and mTOR signaling in NSCLC cells and thus, could be developed as a chemotherapeutic agent against human lung cancer. PMID:21618507

  12. Leucine supplementation of a chronically restricted protein and energy diet enhances mTOR pathway activation but not muscle protein synthesis in neonatal pigs.

    Science.gov (United States)

    Manjarín, Rodrigo; Columbus, Daniel A; Suryawan, Agus; Nguyen, Hanh V; Hernandez-García, Adriana D; Hoang, Nguyet-Minh; Fiorotto, Marta L; Davis, Teresa

    2016-01-01

    Suboptimal nutrient intake represents a limiting factor for growth and long-term survival of low-birth weight infants. The objective of this study was to determine if in neonates who can consume only 70 % of their protein and energy requirements for 8 days, enteral leucine supplementation will upregulate the mammalian target of rapamycin (mTOR) pathway in skeletal muscle, leading to an increase in protein synthesis and muscle anabolism. Nineteen 4-day-old piglets were fed by gastric tube 1 of 3 diets, containing (kg body weight(-1) · day(-1)) 16 g protein and 190 kcal (CON), 10.9 g protein and 132 kcal (R), or 10.8 g protein + 0.2 % leucine and 136 kcal (RL) at 4-h intervals for 8 days. On day 8, plasma AA and insulin levels were measured during 6 post-feeding intervals, and muscle protein synthesis rate and mTOR signaling proteins were determined at 120 min post-feeding. At 120 min, leucine was highest in RL (P protein synthesis, phosphorylation of S6 kinase (p-S6K1) and 4E-binding protein (p-4EBP1), and activation of eukaryotic initiation factor 4 complex (eIF4E · eIF4G). RL increased (P ≤ 0.01) p-S6K1, p-4EBP1 and eIF4E · eIF4G compared to R. In conclusion, when protein and energy intakes are restricted for 8 days, leucine supplementation increases muscle mTOR activation, but does not improve body weight gain or enhance skeletal muscle protein synthesis in neonatal pigs.

  13. MTOR signaling and ubiquitin-proteosome gene expression in the preservation of fat free mass following high protein, calorie restricted weight loss

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    McIver Cassandra M

    2012-09-01

    Full Text Available Abstract Caloric restriction is one of the most efficient ways to promote weight loss and is known to activate protective metabolic pathways. Frequently reported with weight loss is the undesirable consequence of fat free (lean muscle mass loss. Weight loss diets with increased dietary protein intake are popular and may provide additional benefits through preservation of fat free mass compared to a standard protein, high carbohydrate diet. However, the precise mechanism by which a high protein diet may mitigate dietary weight loss induced reductions in fat free mass has not been fully elucidated. Maintenance of fat free mass is dependent upon nutrient stimulation of protein synthesis via the mTOR complex, although during caloric restriction a decrease (atrophy in skeletal muscle may be driven by a homeostatic shift favouring protein catabolism. This review evaluates the relationship between the macronutrient composition of calorie restricted diets and weight loss using metabolic indicators. Specifically we evaluate the effect of increased dietary protein intake and caloric restricted diets on gene expression in skeletal muscle, particularly focusing on biosynthesis, degradation and the expression of genes in the ubiquitin-proteosome (UPP and mTOR signaling pathways, including MuRF-1, MAFbx/atrogin-1, mTORC1, and S6K1.

  14. mTOR pathway is activated in endothelial cells from patients with Takayasu arteritis and is modulated by serum immunoglobulin G.

    Science.gov (United States)

    Hadjadj, Jérôme; Canaud, Guillaume; Mirault, Tristan; Samson, Maxime; Bruneval, Patrick; Régent, Alexis; Goulvestre, Claire; Witko-Sarsat, Véronique; Costedoat-Chalumeau, Nathalie; Guillevin, Loïc; Mouthon, Luc; Terrier, Benjamin

    2018-06-01

    Takayasu arteritis (TA) and GCA are large-vessel vasculitides characterized by vascular remodelling involving endothelial cells (ECs) and vascular smooth muscle cells. Mammalian target of rapamycin (mTOR) pathway has been involved in vascular remodelling. We hypothesized that the mTOR pathway was involved in the pathogenesis of large-vessel vasculitis. We used IF analysis on aortic and temporal artery biopsies from patients with TA and GCA to assess the involvement of the mTOR pathway and searched for antibodies targeting ECs in serum by IIF and cellular ELISA. We evaluated in vitro the effect of purified IgG from patients on mTOR pathway activation and cell proliferation. IF analyses on tissues revealed that both mTORC1 and mTORC2 are activated specifically in ECs from TA patients but not in ECs from GCA patients and healthy controls (HCs). Using IIF and ELISA, we observed higher levels of antibodies binding to ECs in TA patients compared with GCA patients and HCs. Using western blot, we demonstrated that purified IgG from TA patients caused mTORC1 activation in ECs, whereas this effect was not observed with purified IgG from GCA patients or HCs. Purified IgG from TA patients induced a significant EC proliferation compared with to GCA and HC IgG, and this effect was decreased after EC exposure with sirolimus, a specific mTOR inhibitor and PI3K inhibitor. Our results suggest that antibodies targeting ECs drive endothelial remodelling in TA through activation of the mTOR pathway, but not in GCA. Inhibition of the mTOR pathway could represent a therapeutic option in TA.

  15. Metabolic Symbiosis Enables Adaptive Resistance to Anti-angiogenic Therapy that Is Dependent on mTOR Signaling

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    Elizabeth Allen

    2016-05-01

    Full Text Available Therapeutic targeting of tumor angiogenesis with VEGF inhibitors results in demonstrable, but transitory efficacy in certain human tumors and mouse models of cancer, limited by unconventional forms of adaptive/evasive resistance. In one such mouse model, potent angiogenesis inhibitors elicit compartmental reorganization of cancer cells around remaining blood vessels. The glucose and lactate transporters GLUT1 and MCT4 are induced in distal hypoxic cells in a HIF1α-dependent fashion, indicative of glycolysis. Tumor cells proximal to blood vessels instead express the lactate transporter MCT1, and p-S6, the latter reflecting mTOR signaling. Normoxic cancer cells import and metabolize lactate, resulting in upregulation of mTOR signaling via glutamine metabolism enhanced by lactate catabolism. Thus, metabolic symbiosis is established in the face of angiogenesis inhibition, whereby hypoxic cancer cells import glucose and export lactate, while normoxic cells import and catabolize lactate. mTOR signaling inhibition disrupts this metabolic symbiosis, associated with upregulation of the glucose transporter GLUT2.

  16. Bitter melon seed oil may reduce the adiposity through the hypothalamus mTOR signaling in mice fed a high fat diet

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    Yi Xu

    2016-12-01

    Full Text Available Bitter melon seed oil (BMSO was found to have an advantageous effect on anti-obesity. Up to date, the mechanisms underlying this process have been extensively investigated. However, there are very few reports focusing on the roles of central nervous system (CNS involved. In this study, Golgi-Cox staining and western blotting assays were used to examine the hypothalamic spine density and the expression levels of NMDA-2B receptor and P-S6 protein, respectively. A significant reduction concerning hypothalamic spine density was observed in HFD mice, a phenomenon that could be partially rescued by the BMSO administration. Furthermore, it was found that BMSO could also reverse the changes upon the phosphorylation levels of S6, a typical protein involved in mTOR signaling pathway, indicating that mTOR signaling potentially participated in this metabolism regulation. Besides, NMDA-2B levels were up-regulated in HFD mice, which could not be considerably influenced by BMSO. In summary, this study first proposed aberrant hypothalamic plasticity as CNS's roles in BMSO's fat-reducing effects, favoring the better recognition and treatment of the intractable hypothalamic obesity.

  17. Crosstalk of the mTOR network with stress granules and the TGF-beta pathway

    NARCIS (Netherlands)

    Prentzell, Mirja Tamara

    2018-01-01

    Alle organismen en cellen hebben voedingsstoffen nodig om te kunnen groeien en overleven. Het mTOR (mechanistic of mammalian target of rapamycin) kinase is een knooppunt in een complex signaaltransductie netwerk dat celgroei in reactie op voedingsstoffen faciliteert. Ontregeling van dit netwerk

  18. Translational up-regulation and high-level protein expression from plasmid vectors by mTOR activation via different pathways in PC3 and 293T cells.

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    Prashanthi Karyala

    Full Text Available BACKGROUND: Though 293T cells are widely used for expression of proteins from transfected plasmid vectors, the molecular basis for the high-level expression is yet to be understood. We recently identified the prostate carcinoma cell line PC3 to be as efficient as 293T in protein expression. This study was undertaken to decipher the molecular basis of high-level expression in these two cell lines. METHODOLOGY/PRINCIPAL FINDINGS: In a survey of different cell lines for efficient expression of platelet-derived growth factor-B (PDGF-B, β-galactosidase (β-gal and green fluorescent protein (GFP from plasmid vectors, PC3 was found to express at 5-50-fold higher levels compared to the bone metastatic prostate carcinoma cell line PC3BM and many other cell lines. Further, the efficiency of transfection and level of expression of the reporters in PC3 were comparable to that in 293T. Comparative analyses revealed that the high level expression of the reporters in the two cell lines was due to increased translational efficiency. While phosphatidic acid (PA-mediated activation of mTOR, as revealed by drastic reduction in reporter expression by n-butanol, primarily contributed to the high level expression in PC3, multiple pathways involving PA, PI3K/Akt and ERK1/2 appear to contribute to the abundant reporter expression in 293T. Thus the extent of translational up-regulation attained through the concerted activation of mTOR by multiple pathways in 293T could be achieved through its activation primarily by the PA pathway in PC3. CONCLUSIONS/SIGNIFICANCE: Our studies reveal that the high-level expression of proteins from plasmid vectors is effected by translational up-regulation through mTOR activation via different signaling pathways in the two cell lines and that PC3 is as efficient as 293T for recombinant protein expression. Further, PC3 offers an advantage in that the level of expression of the protein can be regulated by simple addition of n-butanol to

  19. Dietary interventions that reduce mTOR activity rescue autistic-like behavioral deficits in mice

    NARCIS (Netherlands)

    Wu, Jiangbo; de Theije, Caroline G M; da Silva, Sofia Lopes; Abbring, Suzanne; van der Horst, Hilma; Broersen, Laus M; Willemsen, Linette; Kas, Martien; Garssen, Johan; Kraneveld, Aletta D

    Enhanced mammalian target of rapamycin (mTOR) signaling in the brain has been implicated in the pathogenesis of autism spectrum disorder (ASD). Inhibition of the mTOR pathway improves behavior and neuropathology in mouse models of ASD containing mTOR-associated single gene mutations. The current

  20. The interaction between early life epilepsy and autistic-like behavioral consequences: a role for the mammalian target of rapamycin (mTOR pathway.

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    Delia M Talos

    Full Text Available Early life seizures can result in chronic epilepsy, cognitive deficits and behavioral changes such as autism, and conversely epilepsy is common in autistic children. We hypothesized that during early brain development, seizures could alter regulators of synaptic development and underlie the interaction between epilepsy and autism. The mammalian Target of Rapamycin (mTOR modulates protein translation and is dysregulated in Tuberous Sclerosis Complex, a disorder characterized by epilepsy and autism. We used a rodent model of acute hypoxia-induced neonatal seizures that results in long term increases in neuronal excitability, seizure susceptibility, and spontaneous seizures, to determine how seizures alter mTOR Complex 1 (mTORC1 signaling. We hypothesized that seizures occurring at a developmental stage coinciding with a critical period of synaptogenesis will activate mTORC1, contributing to epileptic networks and autistic-like behavior in later life. Here we show that in the rat, baseline mTORC1 activation peaks during the first three postnatal weeks, and induction of seizures at postnatal day 10 results in further transient activation of its downstream targets phospho-4E-BP1 (Thr37/46, phospho-p70S6K (Thr389 and phospho-S6 (Ser235/236, as well as rapid induction of activity-dependent upstream signaling molecules, including BDNF, phospho-Akt (Thr308 and phospho-ERK (Thr202/Tyr204. Furthermore, treatment with the mTORC1 inhibitor rapamycin immediately before and after seizures reversed early increases in glutamatergic neurotransmission and seizure susceptibility and attenuated later life epilepsy and autistic-like behavior. Together, these findings suggest that in the developing brain the mTORC1 signaling pathway is involved in epileptogenesis and altered social behavior, and that it may be a target for development of novel therapies that eliminate the progressive effects of neonatal seizures.

  1. Huaier Extract Induces Autophagic Cell Death by Inhibiting the mTOR/S6K Pathway in Breast Cancer Cells.

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    Xiaolong Wang

    Full Text Available Huaier extract is attracting increased attention due to its biological activities, including antitumor, anti-parasite and immunomodulatory effects. Here, we investigated the role of autophagy in Huaier-induced cytotoxicity in MDA-MB-231, MDA-MB-468 and MCF7 breast cancer cells. Huaier treatment inhibited cell viability in all three cell lines and induced various large membranous vacuoles in the cytoplasm. In addition, electron microscopy, MDC staining, accumulated expression of autophagy markers and flow cytometry revealed that Huaier extract triggered autophagy. Inhibition of autophagy attenuated Huaier-induced cell death. Furthermore, Huaier extract inhibited the mammalian target of the rapamycin (mTOR/S6K pathway in breast cancer cells. After implanting MDA-MB-231 cells subcutaneously into the right flank of BALB/c nu/nu mice, Huaier extract induced autophagy and effectively inhibited xenograft tumor growth. This study is the first to show that Huaier-induced cytotoxicity is partially mediated through autophagic cell death in breast cancer cells through suppression of the mTOR/S6K pathway.

  2. Clustered, Regularly Interspaced Short Palindromic Repeats (CRISPR)/Cas9-coupled Affinity Purification/Mass Spectrometry Analysis Revealed a Novel Role of Neurofibromin in mTOR Signaling.

    Science.gov (United States)

    Li, Xu; Gao, Min; Choi, Jong Min; Kim, Beom-Jun; Zhou, Mao-Tian; Chen, Zhen; Jain, Antrix N; Jung, Sung Yun; Yuan, Jingsong; Wang, Wenqi; Wang, Yi; Chen, Junjie

    2017-04-01

    Neurofibromin (NF1) is a well known tumor suppressor that is commonly mutated in cancer patients. It physically interacts with RAS and negatively regulates RAS GTPase activity. Despite the importance of NF1 in cancer, a high quality endogenous NF1 interactome has yet to be established. In this study, we combined c lustered, r egularly i nterspaced s hort p alindromic r epeats (CRISPR)/Cas9-mediated gene knock-out technology with affinity purification using antibodies against endogenous proteins, followed by mass spectrometry analysis, to sensitively and accurately detect NF1 protein-protein interactions in unaltered in vivo settings. Using this system, we analyzed endogenous NF1-associated protein complexes and identified 49 high-confidence candidate interaction proteins, including RAS and other functionally relevant proteins. Through functional validation, we found that NF1 negatively regulates mechanistic target of rapamycin signaling (mTOR) in a LAMTOR1-dependent manner. In addition, the cell growth and survival of NF1-deficient cells have become dependent on hyperactivation of the mTOR pathway, and the tumorigenic properties of these cells have become dependent on LAMTOR1. Taken together, our findings may provide novel insights into therapeutic approaches targeting NF1-deficient tumors. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  3. Resveratrol engages AMPK to attenuate ERK and mTOR signaling in sensory neurons and inhibits incision-induced acute and chronic pain

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    Tillu Dipti V

    2012-01-01

    Full Text Available Abstract Background Despite advances in our understanding of basic mechanisms driving post-surgical pain, treating incision-induced pain remains a major clinical challenge. Moreover, surgery has been implicated as a major cause of chronic pain conditions. Hence, more efficacious treatments are needed to inhibit incision-induced pain and prevent the transition to chronic pain following surgery. We reasoned that activators of AMP-activated protein kinase (AMPK may represent a novel treatment avenue for the local treatment of incision-induced pain because AMPK activators inhibit ERK and mTOR signaling, two important pathways involved in the sensitization of peripheral nociceptors. Results To test this hypothesis we used a potent and efficacious activator of AMPK, resveratrol. Our results demonstrate that resveratrol profoundly inhibits ERK and mTOR signaling in sensory neurons in a time- and concentration-dependent fashion and that these effects are mediated by AMPK activation and independent of sirtuin activity. Interleukin-6 (IL-6 is thought to play an important role in incision-induced pain and resveratrol potently inhibited IL-6-mediated signaling to ERK in sensory neurons and blocked IL-6-mediated allodynia in vivo through a local mechanism of action. Using a model of incision-induced allodynia in mice, we further demonstrate that local injection of resveratrol around the surgical wound strongly attenuates incision-induced allodynia. Intraplantar IL-6 injection and plantar incision induces persistent nociceptive sensitization to PGE2 injection into the affected paw after the resolution of allodynia to the initial stimulus. We further show that resveratrol treatment at the time of IL-6 injection or plantar incision completely blocks the development of persistent nociceptive sensitization consistent with the blockade of a transition to a chronic pain state by resveratrol treatment. Conclusions These results highlight the importance of signaling

  4. The nuclear import of ribosomal proteins is regulated by mTOR

    Science.gov (United States)

    Kazyken, Dubek; Kaz, Yelimbek; Kiyan, Vladimir; Zhylkibayev, Assylbek A.; Chen, Chien-Hung; Agarwal, Nitin K.; Sarbassov, Dos D.

    2014-01-01

    Mechanistic target of rapamycin (mTOR) is a central component of the essential signaling pathway that regulates cell growth and proliferation by controlling anabolic processes in cells. mTOR exists in two distinct mTOR complexes known as mTORC1 and mTORC2 that reside mostly in cytoplasm. In our study, the biochemical characterization of mTOR led to discovery of its novel localization on nuclear envelope where it associates with a critical regulator of nuclear import Ran Binding Protein 2 (RanBP2). We show that association of mTOR with RanBP2 is dependent on the mTOR kinase activity that regulates the nuclear import of ribosomal proteins. The mTOR kinase inhibitors within thirty minutes caused a substantial decrease of ribosomal proteins in the nuclear but not cytoplasmic fraction. Detection of a nuclear accumulation of the GFP-tagged ribosomal protein rpL7a also indicated its dependence on the mTOR kinase activity. The nuclear abundance of ribosomal proteins was not affected by inhibition of mTOR Complex 1 (mTORC1) by rapamycin or deficiency of mTORC2, suggesting a distinctive role of the nuclear envelope mTOR complex in the nuclear import. Thus, we identified that mTOR in association with RanBP2 mediates the active nuclear import of ribosomal proteins. PMID:25294810

  5. Dexamethasone and BCAA Failed to Modulate Muscle Mass and mTOR Signaling in GH-Deficient Rats.

    Science.gov (United States)

    Nishida, Hikaru; Ikegami, Ayaka; Kaneko, Chiaki; Kakuma, Hitomi; Nishi, Hisano; Tanaka, Noriko; Aoyama, Michiko; Usami, Makoto; Okimura, Yasuhiko

    2015-01-01

    Branched-chain amino acids (BCAAs) and IGF-I, the secretion of which is stimulated by growth hormone (GH), prevent muscle atrophy. mTOR plays a pivotal role in the protective actions of BCAA and IGF-1. The pathway by which BCAA activates mTOR is different from that of IGF-1, which suggests that BCAA and GH work independently. We tried to examine whether BCAA exerts a protective effect against dexamethasone (Dex)-induced muscle atrophy independently of GH using GH-deficient spontaneous dwarf rats (SDRs). Unexpectedly, Dex did not induce muscle atrophy assessed by the measurement of cross-sectional area (CSA) of the muscle fibers and did not increase atrogin-1, MuRF1 and REDD1 expressions, which are activated during protein degradation. Glucocorticoid (GR) mRNA levels were higher in SDRs compared to GH-treated SDRs, indicating that the low expression of GR is not the reason of the defect of Dex's action in SDRs. BCAA did not stimulate the phosphorylation of p70S6K or 4E-BP1, which stimulate protein synthesis. BCAA did not decrease the mRNA level of atrogin-1 or MuRF1. These findings suggested that Dex failed to modulate muscle mass and that BCAA was unable to activate mTOR in SDRs because these phosphorylations of p70S6K and 4E-BP1 and the reductions of these mRNAs are regulated by mTOR. In contrast, after GH supplementation, these responses to Dex were normalized and muscle fiber CSA was decreased by Dex. BCAA prevented the Dex-induced decrease in CSA. BCAA increased the phosphorylation of p70S6K and decreased the Dex-induced elevations of atrogin-1 and Bnip3 mRNAs. However, the amount of mTORC1 components including mTOR was not decreased in the SDRs compared to the normal rats. These findings suggest that GH increases mTORC1 activity but not its content to recover the action of BCAA in SDRs and that GH is required for actions of Dex and BCAA in muscles.

  6. Dexamethasone and BCAA Failed to Modulate Muscle Mass and mTOR Signaling in GH-Deficient Rats.

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    Hikaru Nishida

    Full Text Available Branched-chain amino acids (BCAAs and IGF-I, the secretion of which is stimulated by growth hormone (GH, prevent muscle atrophy. mTOR plays a pivotal role in the protective actions of BCAA and IGF-1. The pathway by which BCAA activates mTOR is different from that of IGF-1, which suggests that BCAA and GH work independently. We tried to examine whether BCAA exerts a protective effect against dexamethasone (Dex-induced muscle atrophy independently of GH using GH-deficient spontaneous dwarf rats (SDRs. Unexpectedly, Dex did not induce muscle atrophy assessed by the measurement of cross-sectional area (CSA of the muscle fibers and did not increase atrogin-1, MuRF1 and REDD1 expressions, which are activated during protein degradation. Glucocorticoid (GR mRNA levels were higher in SDRs compared to GH-treated SDRs, indicating that the low expression of GR is not the reason of the defect of Dex's action in SDRs. BCAA did not stimulate the phosphorylation of p70S6K or 4E-BP1, which stimulate protein synthesis. BCAA did not decrease the mRNA level of atrogin-1 or MuRF1. These findings suggested that Dex failed to modulate muscle mass and that BCAA was unable to activate mTOR in SDRs because these phosphorylations of p70S6K and 4E-BP1 and the reductions of these mRNAs are regulated by mTOR. In contrast, after GH supplementation, these responses to Dex were normalized and muscle fiber CSA was decreased by Dex. BCAA prevented the Dex-induced decrease in CSA. BCAA increased the phosphorylation of p70S6K and decreased the Dex-induced elevations of atrogin-1 and Bnip3 mRNAs. However, the amount of mTORC1 components including mTOR was not decreased in the SDRs compared to the normal rats. These findings suggest that GH increases mTORC1 activity but not its content to recover the action of BCAA in SDRs and that GH is required for actions of Dex and BCAA in muscles.

  7. Discrete functions of mTOR signaling in iNKT cell development and NKT17 fate decision

    OpenAIRE

    Wei, Jun; Yang, Kai; Chi, Hongbo

    2014-01-01

    Invariant natural killer T (iNKT) cells have been recently classified into NKT1, NKT2 and NKT17 lineages with distinct transcription factor and cytokine profiles, but mechanisms underlying such fate decisions remain elusive. Here, we report crucial roles of mTOR signaling especially mTORC2 in iNKT cell development and fate determination of NKT17 cells. Loss of Rictor, an obligatory component of mTORC2, decreased thymic and peripheral iNKT cells, associated with defective survival. Strikingly,...

  8. DMPD: Signal integration between IFNgamma and TLR signalling pathways in macrophages. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 16920490 Signal integration between IFNgamma and TLR signalling pathways in macroph...tml) (.csml) Show Signal integration between IFNgamma and TLR signalling pathways in macrophages. PubmedID 16920490 Title Signal inte...gration between IFNgamma and TLR signalling pathways in

  9. AKT inhibitors promote cell death in cervical cancer through disruption of mTOR signaling and glucose uptake.

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    Ramachandran Rashmi

    Full Text Available PI3K/AKT pathway alterations are associated with incomplete response to chemoradiation in human cervical cancer. This study was performed to test for mutations in the PI3K pathway and to evaluate the effects of AKT inhibitors on glucose uptake and cell viability.Mutational analysis of DNA from 140 pretreatment tumor biopsies and 8 human cervical cancer cell lines was performed. C33A cells (PIK3CAR88Q and PTENR233* were treated with increasing concentrations of two allosteric AKT inhibitors (SC-66 and MK-2206 with or without the glucose analogue 2-deoxyglucose (2-DG. Cell viability and activation status of the AKT/mTOR pathway were determined in response to the treatment. Glucose uptake was evaluated by incubation with 18F-fluorodeoxyglucose (FDG. Cell migration was assessed by scratch assay.Activating PIK3CA (E545K, E542K and inactivating PTEN (R233* mutations were identified in human cervical cancer. SC-66 effectively inhibited AKT, mTOR and mTOR substrates in C33A cells. SC-66 inhibited glucose uptake via reduced delivery of Glut1 and Glut4 to the cell membrane. SC-66 (1 µg/ml-56% and MK-2206 (30 µM-49% treatment decreased cell viability through a non-apoptotic mechanism. Decreases in cell viability were enhanced when AKT inhibitors were combined with 2-DG. The scratch assay showed a substantial reduction in cell migration upon SC-66 treatment.The mutational spectrum of the PI3K/AKT pathway in cervical cancer is complex. AKT inhibitors effectively block mTORC1/2, decrease glucose uptake, glycolysis, and decrease cell viability in vitro. These results suggest that AKT inhibitors may improve response to chemoradiation in cervical cancer.

  10. Ropinirole and Pramipexole Promote Structural Plasticity in Human iPSC-Derived Dopaminergic Neurons via BDNF and mTOR Signaling

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    Ginetta Collo

    2018-01-01

    Full Text Available The antiparkinsonian ropinirole and pramipexole are D3 receptor- (D3R- preferring dopaminergic (DA agonists used as adjunctive therapeutics for the treatment resistant depression (TRD. While the exact antidepressant mechanism of action remains uncertain, a role for D3R in the restoration of impaired neuroplasticity occurring in TRD has been proposed. Since D3R agonists are highly expressed on DA neurons in humans, we studied the effect of ropinirole and pramipexole on structural plasticity using a translational model of human-inducible pluripotent stem cells (hiPSCs. Two hiPSC clones from healthy donors were differentiated into midbrain DA neurons. Ropinirole and pramipexole produced dose-dependent increases of dendritic arborization and soma size after 3 days of culture, effects antagonized by the selective D3R antagonists SB277011-A and S33084 and by the mTOR pathway kinase inhibitors LY294002 and rapamycin. All treatments were also effective in attenuating the D3R-dependent increase of p70S6-kinase phosphorylation. Immunoneutralisation of BDNF, inhibition of TrkB receptors, and blockade of MEK-ERK signaling likewise prevented ropinirole-induced structural plasticity, suggesting a critical interaction between BDNF and D3R signaling pathways. The highly similar profiles of data acquired with DA neurons derived from two hiPSC clones underpin their reliability for characterization of pharmacological agents acting via dopaminergic mechanisms.

  11. Determination and validation of mTOR kinase-domain 3D structure by homology modeling

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    Lakhlili W

    2015-07-01

    Full Text Available Wiame Lakhlili,1 Gwénaël Chevé,2 Abdelaziz Yasri,2 Azeddine Ibrahimi1 1Laboratoire de Biotechnologie (MedBiotech, Faculté de Médecine et de Pharmacie de Rabat, Université Mohammed V de Rabat, Rabat, Morroco; 2OriBase Pharma, Cap Gamma, Parc Euromédecine, Montpellier, France Abstract: The AKT/mammalian target of rapamycin (mTOR pathway is considered as one of the commonly activated and deregulated signaling pathways in human cancer. mTOR is associated with other proteins in two molecular complexes: mTOR complex 1/Raptor and the mTOR complex 2/Rictor. Using the crystal structure of the related lipid kinase PI3Kγ, we built a model of the catalytic region of mTOR. The modeling of the three-dimensional (3D structure of the mTOR was performed by homology modeling program SWISS-MODEL. The quality and validation of the obtained model were performed using PROCHECK and PROVE softwares. The overall stereochemical property of the protein was assessed by the Ramachandran plot. The model validation was also done by docking of known inhibitors. In this paper, we describe and validate a 3D model for the mTOR catalytic site.Keywords: mTOR, homology modeling, mTOR kinase-domain, docking

  12. Antidepressant action of ketamine via mTOR is mediated by inhibition of nitrergic Rheb degradation.

    Science.gov (United States)

    Harraz, M M; Tyagi, R; Cortés, P; Snyder, S H

    2016-03-01

    As traditional antidepressants act only after weeks/months, the discovery that ketamine, an antagonist of glutamate/N-methyl-D-aspartate (NMDA) receptors, elicits antidepressant actions in hours has been transformative. Its mechanism of action has been elusive, though enhanced mammalian target of rapamycin (mTOR) signaling is a major feature. We report a novel signaling pathway wherein NMDA receptor activation stimulates generation of nitric oxide (NO), which S-nitrosylates glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Nitrosylated GAPDH complexes with the ubiquitin-E3-ligase Siah1 and Rheb, a small G protein that activates mTOR. Siah1 degrades Rheb leading to reduced mTOR signaling, while ketamine, conversely, stabilizes Rheb that enhances mTOR signaling. Drugs selectively targeting components of this pathway may offer novel approaches to the treatment of depression.

  13. The PTPN11 loss-of-function mutation Q510E-Shp2 causes hypertrophic cardiomyopathy by dysregulating mTOR signaling.

    Science.gov (United States)

    Schramm, Christine; Fine, Deborah M; Edwards, Michelle A; Reeb, Ashley N; Krenz, Maike

    2012-01-01

    The identification of mutations in PTPN11 (encoding the protein tyrosine phosphatase Shp2) in families with congenital heart disease has facilitated mechanistic studies of various cardiovascular defects. However, the roles of normal and mutant Shp2 in the developing heart are still poorly understood. Furthermore, it remains unclear how Shp2 loss-of-function (LOF) mutations cause LEOPARD Syndrome (also termed Noonan Syndrome with multiple lentigines), which is characterized by congenital heart defects such as pulmonary valve stenosis and hypertrophic cardiomyopathy (HCM). In normal hearts, Shp2 controls cardiomyocyte size by regulating signaling through protein kinase B (Akt) and mammalian target of rapamycin (mTOR). We hypothesized that Shp2 LOF mutations dysregulate this pathway, resulting in HCM. For our studies, we chose the Shp2 mutation Q510E, a dominant-negative LOF mutation associated with severe early onset HCM. Newborn mice with cardiomyocyte-specific overexpression of Q510E-Shp2 starting before birth displayed increased cardiomyocyte sizes, heart-to-body weight ratios, interventricular septum thickness, and cardiomyocyte disarray. In 3-mo-old hearts, interstitial fibrosis was detected. Echocardiographically, ventricular walls were thickened and contractile function was depressed. In ventricular tissue samples, signaling through Akt/mTOR was hyperactivated, indicating that the presence of Q510E-Shp2 led to upregulation of this pathway. Importantly, rapamycin treatment started shortly after birth rescued the Q510E-Shp2-induced phenotype in vivo. If rapamycin was started at 6 wk of age, HCM was also ameliorated. We also generated a second mouse model in which cardiomyocyte-specific Q510E-Shp2 overexpression started after birth. In contrast to the first model, these mice did not develop HCM. In summary, our studies establish a role for mTOR signaling in HCM caused by Q510E-Shp2. Q510E-Shp2 overexpression in the cardiomyocyte population alone was sufficient to

  14. Reduced neuronal size and mTOR pathway activity in the Mecp2 A140V Rett syndrome mouse model [version 1; referees: 2 approved

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    Sampathkumar Rangasamy

    2016-09-01

    Full Text Available Rett syndrome (RTT is a neurodevelopmental disorder caused by mutation in the X-linked MECP2 gene, encoding methyl-CpG-binding protein 2. We have created a mouse model (Mecp2 A140V “knock-in” mutant expressing the recurrent human MECP2 A140V mutation linked to an X-linked mental retardation/Rett syndrome phenotype. Morphological analyses focused on quantifying soma and nucleus size were performed on primary hippocampus and cerebellum granule neuron (CGN cultures from mutant (Mecp2A140V/y and wild type (Mecp2+/y male mice. Cultured hippocampus and cerebellar granule neurons from mutant animals were significantly smaller than neurons from wild type animals. We also examined soma size in hippocampus neurons from individual female transgenic mice that express both a mutant  (maternal allele and a wild type Mecp2 gene linked to an eGFP transgene (paternal allele. In cultures from such doubly heterozygous female mice, the size of neurons expressing the mutant (A140V allele also showed a significant reduction compared to neurons expressing wild type MeCP2, supporting a cell-autonomous role for MeCP2 in neuronal development. IGF-1 (insulin growth factor-1 treatment of neuronal cells from Mecp2 mutant mice rescued the soma size phenotype. We also found that Mecp2  mutation leads to down-regulation of the mTOR signaling pathway, known to be involved in neuronal size regulation. Our results suggest that i reduced neuronal size is an important in vitro cellular phenotype of Mecp2 mutation in mice, and ii MeCP2 might play a critical role in the maintenance of neuronal structure by modulation of the mTOR pathway. The definition of a quantifiable cellular phenotype supports using neuronal size as a biomarker in the development of a high-throughput, in vitro assay to screen for compounds that rescue small neuronal phenotype (“phenotypic assay”.

  15. TIME COURSE CHANGE OF IGF1/AKT/MTOR/P70S6K PATHWAY ACTIVATION IN RAT GASTROCNEMIUS MUSCLE DURING REPEATED BOUTS OF ECCENTRIC EXERCISE

    Directory of Open Access Journals (Sweden)

    Eisuke Ochi

    2010-06-01

    Full Text Available The purpose of this study was to examine whether insulin-like growth factor (IGF-1 and Akt/mTOR/p70S6K pathway activity is altered by chronic eccentric exercise in rat medial gastrocnemius muscle. Male Wistar rats (n = 24 were randomly assigned to 1 of the 2 groups: eccentric exercise (ECC group or sham-operated control (CON group. Rats in the ECC group were trained every second day for 10 days (5 sessions in total or 20 days (10 sessions in total. After either 5 or 10 exercise sessions, muscle specimens were dissected and weighed. The mRNA expression of IGF-1 and its variant, mechano growth factor (MGF, was evaluated using real time reverse transcriptase-polymerase chain reaction (RT-PCR. Tissue concentrations of Akt (P, mTOR (P, and p70S6K (P were measured by using western blot analysis. The medial gastrocnemius muscle mass of the ECC group did not show any significant difference after 5 exercise sessions, whereas the muscle mass increased significantly after 10 exercise sessions with a concomitant increase in the cross-sectional area of muscle fibers (p < 0.05. The expression of IGF-1 mRNA and the tissue concentrations of Akt (P and p70S6K (P after 10 exercise sessions was significantly higher than those of the age-matched controls and the rats that received 5 exercise sessions. The expression of MGF mRNA in both ECC5S and ECC10S were significantly higher than that in each period-matched control (p < 0.01. The tissue concentration of mTOR (P after 10 sessions showed a significant increase when compared with period-matched controls (p < 0.01. These results suggest that activation of the IGF-1/Akt/mTOR/p70S6K signaling pathway becomes dominant in the later phase of chronic exercise, when significant muscular hypertrophy is observed

  16. Lactic acid in tumor microenvironments causes dysfunction of NKT cells by interfering with mTOR signaling.

    Science.gov (United States)

    Xie, Di; Zhu, Shasha; Bai, Li

    2016-12-01

    Cellular metabolism has been shown to regulate differentiation and function of immune cells. Tumor associated immune cells undergo phenotypic and functional alterations due to the change of cellular metabolism in tumor microenvironments. NKT cells are good candidates for immunotherapies against tumors and have been used in several clinical trials. However, the influences of tumor microenvironments on NKT cell functions remain unclear. In our studies, lactic acid in tumor microenvironments inhibited IFNγ and IL4 productions from NKT cells, and more profound influence on IFNγ was observed. By adjusting the pH of culture medium we further showed that, dysfunction of NKT cells could simply be induced by low extracellular pH. Moreover, low extracellular pH inhibited NKT cell functions by inhibiting mammalian target of rapamycin (mTOR) signaling and nuclear translocation of promyelocytic leukemia zinc-finger (PLZF). Together, our results suggest that tumor acidic microenvironments could interfere with NKT cell functions through metabolic controls.

  17. Effects of Arginine Concentration on the In Vitro Expression of Casein and mTOR Pathway Related Genes in Mammary Epithelial Cells from Dairy Cattle

    Science.gov (United States)

    Wang, Mengzhi; Xu, Bolin; Wang, Hongrong; Bu, Dengpan; Wang, Jiaqi; Loor, Juan-Jose

    2014-01-01

    Arginine (Arg) is a conditionally-essential amino acid that is taken up by bovine mammary gland in excess of its output in milk. In this study we evaluated the effects of Arg concentration on the expression of casein and signaling pathway-related genes in mammary epithelial cells. The treatments (applied for 24 h) were designed to be devoid of Arg 0X (control; 0.00 mg/L), resemble the profile of Arg in casein (Arg 1X; 278.00 mg/L), be deficient [Arg 0.25X (69.50 mg/L) and Arg 0.5X (139.00 mg/L)], or be in excess of the amount in casein [Arg 2X (556.00 mg/L), Arg 4X (1,112 mg/L), and Arg 8X (2,224 mg/L)]. The expression of CSN1S, CSN3 and mTOR in the experimental groups was higher than those of the control group (P0.05), the expression of CSN1S2, CSN2 and JAK2 in other experimental groups was higher (P0.05), the expression of STAT5 in the other experimental groups was higher than those of the control (Pcasein genes and mTOR-related genes in bovine mammary epithelial cells. PMID:24788778

  18. β-Hydroxy-β-methylbutyrate (HMβ supplementation stimulates skeletal muscle hypertrophy in rats via the mTOR pathway

    Directory of Open Access Journals (Sweden)

    Pimentel Gustavo D

    2011-02-01

    Full Text Available Abstract β-Hydroxy-β-methylbutyrate (HMβ supplementation is used to treat cancer, sepsis and exercise-induced muscle damage. However, its effects on animal and human health and the consequences of this treatment in other tissues (e.g., fat and liver have not been examined. The purpose of this study was to evaluate the effects of HMβ supplementation on skeletal muscle hypertrophy and the expression of proteins involved in insulin signalling. Rats were treated with HMβ (320 mg/kg body weight or saline for one month. The skeletal muscle hypertrophy and insulin signalling were evaluated by western blotting, and hormonal concentrations were evaluated using ELISAs. HMβ supplementation induced muscle hypertrophy in the extensor digitorum longus (EDL and soleus muscles and increased serum insulin levels, the expression of the mammalian target of rapamycin (mTOR and phosphorylation of p70S6K in the EDL muscle. Expression of the insulin receptor was increased only in liver. Thus, our results suggest that HMβ supplementation can be used to increase muscle mass without adverse health effects.

  19. Decoding resistant hypertension signalling pathways.

    Science.gov (United States)

    Parreira, Ricardo Cambraia; Lacerda, Leandro Heleno Guimarães; Vasconcellos, Rebecca; Lima, Swiany Silveira; Santos, Anderson Kenedy; Fontana, Vanessa; Sandrim, Valéria Cristina; Resende, Rodrigo Ribeiro

    2017-12-01

    Resistant hypertension (RH) is a clinical condition in which the hypertensive patient has become resistant to drug therapy and is often associated with increased cardiovascular morbidity and mortality. Several signalling pathways have been studied and related to the development and progression of RH: modulation of sympathetic activity by leptin and aldosterone, primary aldosteronism, arterial stiffness, endothelial dysfunction and variations in the renin-angiotensin-aldosterone system (RAAS). miRNAs comprise a family of small non-coding RNAs that participate in the regulation of gene expression at post-transcriptional level. miRNAs are involved in the development of both cardiovascular damage and hypertension. Little is known of the molecular mechanisms that lead to development and progression of this condition. This review aims to cover the potential roles of miRNAs in the mechanisms associated with the development and consequences of RH, and explore the current state of the art of diagnostic and therapeutic tools based on miRNA approaches. © 2017 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

  20. Dietary interventions that reduce mTOR activity rescue autistic-like behavioral deficits in mice.

    Science.gov (United States)

    Wu, Jiangbo; de Theije, Caroline G M; da Silva, Sofia Lopes; Abbring, Suzanne; van der Horst, Hilma; Broersen, Laus M; Willemsen, Linette; Kas, Martien; Garssen, Johan; Kraneveld, Aletta D

    2017-01-01

    Enhanced mammalian target of rapamycin (mTOR) signaling in the brain has been implicated in the pathogenesis of autism spectrum disorder (ASD). Inhibition of the mTOR pathway improves behavior and neuropathology in mouse models of ASD containing mTOR-associated single gene mutations. The current study demonstrated that the amino acids histidine, lysine, threonine inhibited mTOR signaling and IgE-mediated mast cell activation, while the amino acids leucine, isoleucine, valine had no effect on mTOR signaling in BMMCs. Based on these results, we designed an mTOR-targeting amino acid diet (Active 1 diet) and assessed the effects of dietary interventions with the amino acid diet or a multi-nutrient supplementation diet (Active 2 diet) on autistic-like behavior and mTOR signaling in food allergic mice and in inbred BTBR T+Itpr3tf/J mice. Cow's milk allergic (CMA) or BTBR male mice were fed a Control, Active 1, or Active 2 diet for 7 consecutive weeks. CMA mice showed reduced social interaction and increased self-grooming behavior. Both diets reversed behavioral impairments and inhibited the mTOR activity in the prefrontal cortex and amygdala of CMA mice. In BTBR mice, only Active 1 diet reduced repetitive self-grooming behavior and attenuated the mTOR activity in the prefrontal and somatosensory cortices. The current results suggest that activated mTOR signaling pathway in the brain may be a convergent pathway in the pathogenesis of ASD bridging genetic background and environmental triggers (food allergy) and that mTOR over-activation could serve as a potential therapeutic target for the treatment of ASD. Copyright © 2016. Published by Elsevier Inc.

  1. EGFR targeting monoclonal antibody combines with an mTOR inhibitor and potentiates tumor inhibition by acting on complementary signaling hubs

    International Nuclear Information System (INIS)

    James, Roshan; Vishwakarma, Siddharth; Chivukula, Indira V; Basavaraj, Chetana; Melarkode, Ramakrishnan; Montero, Enrique; Nair, Pradip

    2012-01-01

    Nimotuzumab, an anti-epidermal growth factor receptor (anti-EGFR) monoclonal antibody, has been used extensively in many solid tumors and confers significant survival advantage. The antibody has limited skin toxicity and is generally well tolerated. Similar to other anti-EGFR therapies, patients may relapse a few months after treatment. In this study we show for the first time, the use of Nimotuzumab along with Sirolimus has synergistic effect on tumor inhibition as compared with the drugs used individually, in Nimotuzumab responsive and nonresponsive cell lines. In vitro studies prove that while Sirolimus (25 nmol/L) affects the signal downstream to mammalian target of rapamycin (mTOR), Nimotuzumab (83 nmol/L) downregulates pTYR, pMAPK and pSTAT3 by 40%, 20% and 30%, respectively. The combination, targeting these two different signaling hubs, may be associated with the synergistic inhibition observed. In vivo, the use of half human therapeutic equivalent doses for both the drugs substantially reduces tumors established in nude as well as severe combined immunodeficiency (SCID) mice by EGFR overexpressing A-431 cells. The drug combination reduces cell proliferation and the expression of signal transduction molecules. Treated tumors are better differentiated as compared with those established in the control mice. Tumor microarray demonstrates that Nimotuzumab and the combination groups segregate independently to the Sirolimus and the control treatment. The combination uniquely downregulated 55% of the altered tumor genes, extending beyond the typical pathways associated with Nimotuzumab and Sirolimus downstream pathways inhibition. These results would suggest that this nontoxic drug combination improves therapeutic benefit even in patients with low-EGFR expression and severely immunocompromised because of their current medication

  2. Skeletal myocyte hypertrophy requires mTOR kinase activity and S6K1

    International Nuclear Information System (INIS)

    Park, In-Hyun; Erbay, Ebru; Nuzzi, Paul; Chen Jie

    2005-01-01

    The protein kinase mammalian target of rapamycin (mTOR) is a central regulator of cell proliferation and growth, with the ribosomal subunit S6 kinase 1 (S6K1) as one of the key downstream signaling effectors. A critical role of mTOR signaling in skeletal muscle differentiation has been identified recently, and an unusual regulatory mechanism independent of mTOR kinase activity and S6K1 is revealed. An mTOR pathway has also been reported to regulate skeletal muscle hypertrophy, but the regulatory mechanism is not completely understood. Here, we report the investigation of mTOR's function in insulin growth factor I (IGF-I)-induced C2C12 myotube hypertrophy. Added at a later stage when rapamycin no longer had any effect on normal myocyte differentiation, rapamycin completely blocked myocyte hypertrophy as measured by myotube diameter. Importantly, a concerted increase of average myonuclei per myotube was observed in IGF-I-stimulated myotubes, which was also inhibited by rapamycin added at a time when it no longer affected normal differentiation. The mTOR protein level, its catalytic activity, its phosphorylation on Ser2448, and the activity of S6K1 were all found increased in IGF-I-stimulated myotubes compared to unstimulated myotubes. Using C2C12 cells stably expressing rapamycin-resistant forms of mTOR and S6K1, we provide genetic evidence for the requirement of mTOR and its downstream effector S6K1 in the regulation of myotube hypertrophy. Our results suggest distinct mTOR signaling mechanisms in different stages of skeletal muscle development: While mTOR regulates the initial myoblast differentiation in a kinase-independent and S6K1-independent manner, the hypertrophic function of mTOR requires its kinase activity and employs S6K1 as a downstream effector

  3. Modularized Smad-regulated TGFβ signaling pathway.

    Science.gov (United States)

    Li, Yongfeng; Wang, Minli; Carra, Claudio; Cucinotta, Francis A

    2012-12-01

    The transforming Growth Factor β (TGFβ) signaling pathway is a prominent regulatory signaling pathway controlling various important cellular processes. TGFβ signaling can be induced by several factors including ionizing radiation. The pathway is regulated in a negative feedback loop through promoting the nuclear import of the regulatory Smads and a subsequent expression of inhibitory Smad7, that forms ubiquitin ligase with Smurf2, targeting active TGFβ receptors for degradation. In this work, we proposed a mathematical model to study the Smad-regulated TGFβ signaling pathway. By modularization, we are able to analyze mathematically each component subsystem and recover the nonlinear dynamics of the entire network system. Meanwhile the excitability, a common feature observed in the biological systems, in the TGFβ signaling pathway is discussed and supported as well by numerical simulation, indicating the robustness of the model. Published by Elsevier Inc.

  4. Comparison of growth factor signalling pathway utilisation in cultured normal melanocytes and melanoma cell lines

    International Nuclear Information System (INIS)

    Kim, Ji Eun; Stones, Clare; Joseph, Wayne R; Leung, Euphemia; Finlay, Graeme J; Shelling, Andrew N; Phillips, Wayne A; Shepherd, Peter R; Baguley, Bruce C

    2012-01-01

    The phosphatidylinositol-3-kinase (PI3K-PKB), mitogen activated protein kinase (MEK-ERK) and the mammalian target of rapamycin (mTOR- p70S6K), are thought to regulate many aspects of tumour cell proliferation and survival. We have examined the utilisation of these three signalling pathways in a number of cell lines derived from patients with metastatic malignant melanoma of known PIK3CA, PTEN, NRAS and BRAF mutational status. Western blotting was used to compare the phosphorylation status of components of the PI3K-PKB, MEK-ERK and mTOR-p70S6K signalling pathways, as indices of pathway utilisation. Normal melanocytes could not be distinguished from melanoma cells on the basis of pathway utilisation when grown in the presence of serum, but could be distinguished upon serum starvation, where signalling protein phosphorylation was generally abrogated. Surprisingly, the differential utilisation of individual pathways was not consistently associated with the presence of an oncogenic or tumour suppressor mutation of genes in these pathways. Utilisation of the PI3K-PKB, MEK-ERK and mTOR-p70S6K signalling pathways in melanoma, as determined by phosphorylation of signalling components, varies widely across a series of cell lines, and does not directly reflect mutation of genes coding these components. The main difference between cultured normal melanocytes and melanoma cells is not the pathway utilisation itself, but rather in the serum dependence of pathway utilisation

  5. LMW-E/CDK2 Deregulates Acinar Morphogenesis, Induces Tumorigenesis, and Associates with the Activated b-Raf-ERK1/2-mTOR Pathway in Breast Cancer Patients

    Science.gov (United States)

    Duong, MyLinh T.; Akli, Said; Wei, Caimiao; Wingate, Hannah F.; Liu, Wenbin; Lu, Yiling; Yi, Min; Mills, Gordon B.; Hunt, Kelly K.; Keyomarsi, Khandan

    2012-01-01

    Elastase-mediated cleavage of cyclin E generates low molecular weight cyclin E (LMW-E) isoforms exhibiting enhanced CDK2–associated kinase activity and resistance to inhibition by CDK inhibitors p21 and p27. Approximately 27% of breast cancers express high LMW-E protein levels, which significantly correlates with poor survival. The objective of this study was to identify the signaling pathway(s) deregulated by LMW-E expression in breast cancer patients and to identify pharmaceutical agents to effectively target this pathway. Ectopic LMW-E expression in nontumorigenic human mammary epithelial cells (hMECs) was sufficient to generate xenografts with greater tumorigenic potential than full-length cyclin E, and the tumorigenicity was augmented by in vivo passaging. However, cyclin E mutants unable to interact with CDK2 protected hMECs from tumor development. When hMECs were cultured on Matrigel, LMW-E mediated aberrant acinar morphogenesis, including enlargement of acinar structures and formation of multi-acinar complexes, as denoted by reduced BIM and elevated Ki67 expression. Similarly, inducible expression of LMW-E in transgenic mice generated hyper-proliferative terminal end buds resulting in enhanced mammary tumor development. Reverse-phase protein array assay of 276 breast tumor patient samples and cells cultured on monolayer and in three-dimensional Matrigel demonstrated that, in terms of protein expression profile, hMECs cultured in Matrigel more closely resembled patient tissues than did cells cultured on monolayer. Additionally, the b-Raf-ERK1/2-mTOR pathway was activated in LMW-E–expressing patient samples, and activation of this pathway was associated with poor disease-specific survival. Combination treatment using roscovitine (CDK inhibitor) plus either rapamycin (mTOR inhibitor) or sorafenib (a pan kinase inhibitor targeting b-Raf) effectively prevented aberrant acinar formation in LMW-E–expressing cells by inducing G1/S cell cycle arrest. LMW

  6. The Role of the Mammalian Target of Rapamycin (mTOR) in Pulmonary Fibrosis

    Science.gov (United States)

    Nho, Richard

    2018-01-01

    The phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR)-dependent pathway is one of the most integral pathways linked to cell metabolism, proliferation, differentiation, and survival. This pathway is dysregulated in a variety of diseases, including neoplasia, immune-mediated diseases, and fibroproliferative diseases such as pulmonary fibrosis. The mTOR kinase is frequently referred to as the master regulator of this pathway. Alterations in mTOR signaling are closely associated with dysregulation of autophagy, inflammation, and cell growth and survival, leading to the development of lung fibrosis. Inhibitors of mTOR have been widely studied in cancer therapy, as they may sensitize cancer cells to radiation therapy. Studies also suggest that mTOR inhibitors are promising modulators of fibroproliferative diseases such as idiopathic pulmonary fibrosis (IPF) and radiation-induced pulmonary fibrosis (RIPF). Therefore, mTOR represents an attractive and unique therapeutic target in pulmonary fibrosis. In this review, we discuss the pathological role of mTOR kinase in pulmonary fibrosis and examine how mTOR inhibitors may mitigate fibrotic progression. PMID:29518028

  7. Targeting Signaling Pathways in Epithelial Ovarian Cancer

    Directory of Open Access Journals (Sweden)

    Johannes Haybaeck

    2013-05-01

    Full Text Available Ovarian carcinoma (OC is the most lethal gynecological malignancy. Response to platinum-based chemotherapy is poor in some patients and, thus, current research is focusing on new therapy options. The various histological types of OC are characterized by distinctive molecular genetic alterations that are relevant for ovarian tumorigenesis. The understanding of these molecular pathways is essential for the development of novel therapeutic strategies. Purpose: We want to give an overview on the molecular genetic changes of the histopathological types of OC and their role as putative therapeutic targets. In Depth Review of Existing Data: In 2012, the vascular endothelial growth factor (VEGF inhibitor, bevacizumab, was approved for OC treatment. Bevacizumab has shown promising results as single agent and in combination with conventional chemotherapy, but its target is not distinctive when analyzed before treatment. At present, mammalian target of rapamycin (mTOR inhibitors, poly-ADP-ribose polymerase (PARP inhibitors and components of the EGFR pathway are in the focus of clinical research. Interestingly, some phytochemical substances show good synergistic effects when used in combination with chemotherapy. Conclusion: Ongoing studies of targeted agents in conjunction with chemotherapy will show whether there are alternative options to bevacizumab available for OC patients. Novel targets which can be assessed before therapy to predict efficacy are needed. The assessment of therapeutic targets is continuously improved by molecular pathological analyses on tumor tissue. A careful selection of patients for personalized treatment will help to reduce putative side effects and toxicity.

  8. Functions and Signaling Pathways of Amino Acids in Intestinal Inflammation

    Directory of Open Access Journals (Sweden)

    Fang He

    2018-01-01

    Full Text Available Intestine is always exposed to external environment and intestinal microorganism; thus it is more sensitive to dysfunction and dysbiosis, leading to intestinal inflammation, such as inflammatory bowel disease (IBD, irritable bowel syndrome (IBS, and diarrhea. An increasing number of studies indicate that dietary amino acids play significant roles in preventing and treating intestinal inflammation. The review aims to summarize the functions and signaling mechanisms of amino acids in intestinal inflammation. Amino acids, including essential amino acids (EAAs, conditionally essential amino acids (CEAAs, and nonessential amino acids (NEAAs, improve the functions of intestinal barrier and expressions of anti-inflammatory cytokines and tight junction proteins but decrease oxidative stress and the apoptosis of enterocytes as well as the expressions of proinflammatory cytokines in the intestinal inflammation. The functions of amino acids are associated with various signaling pathways, including mechanistic target of rapamycin (mTOR, inducible nitric oxide synthase (iNOS, calcium-sensing receptor (CaSR, nuclear factor-kappa-B (NF-κB, mitogen-activated protein kinase (MAPK, nuclear erythroid-related factor 2 (Nrf2, general controlled nonrepressed kinase 2 (GCN2, and angiotensin-converting enzyme 2 (ACE2.

  9. Modularized TGFbeta-Smad Signaling Pathway

    Science.gov (United States)

    Li, Yongfeng; Wang, M.; Carra, C.; Cucinotta, F. A.

    2011-01-01

    The Transforming Growth Factor beta (TGFbeta) signaling pathway is a prominent regulatory signaling pathway controlling various important cellular processes. It can be induced by several factors, including ionizing radiation. It is regulated by Smads in a negative feedback loop through promoting increases in the regulatory Smads in the cell nucleus, and subsequent expression of inhibitory Smad, Smad7 to form a ubiquitin ligase with Smurf targeting active TGF receptors for degradation. In this work, we proposed a mathematical model to study the radiation-induced Smad-regulated TGF signaling pathway. By modularization, we are able to analyze each module (subsystem) and recover the nonlinear dynamics of the entire network system. Meanwhile the excitability, a common feature observed in the biological systems, along the TGF signaling pathway is discussed by mathematical analysis and numerical simulation.

  10. Targeting Glutamatergic Signaling and the PI3 Kinase Pathway to Halt Melanoma Progression

    Directory of Open Access Journals (Sweden)

    Stephen A. Rosenberg

    2015-02-01

    Full Text Available Our group has previously reported that the majority of human melanomas (>60% express the metabotropic glutamate receptor 1 (GRM1 and that the glutamate release inhibitor riluzole, a drug currently used to treat amyotrophic lateral sclerosis, can induce apoptosis in GRM1-expressing melanoma cells. Our group previously reported that in vitro riluzole treatment reduces cell growth in three-dimensional (3D soft agar colony assays by 80% in cells with wildtype phosphoinositide 3-kinase (PI3K pathway activation. However, melanoma cell lines harboring constitutive activating mutations of the PI3K pathway (PTEN and NRAS mutations showed only a 35% to 40% decrease in colony formation in soft agar in the presence of riluzole. In this study, we have continued our preclinical studies of riluzole and its effect on melanoma cells alone and in combination with inhibitors of the PI3 kinase pathway: the AKT inhibitor, API-2, and the mammalian target of rapamycin (mTOR inhibitor, rapamycin. We modeled these combinatorial therapies on various melanoma cell lines in 3D and 2D systems and in vivo. Riluzole combined with mTOR inhibition is more effective at halting melanoma anchorage-independent growth and xenograft tumor progression than either agent alone. PI3K signaling changes associated with this combinatorial treatment shows that 3D (nanoculture modeling of cell signaling more closely resembles in vivo signaling than monolayer models. Riluzole combined with mTOR inhibition is effective at halting tumor cell progression independent of BRAF mutational status. This makes this combinatorial therapy a potentially viable alternative for metastatic melanoma patients who are BRAF WT and are therefore ineligible for vemurafenib therapy.

  11. Signaling pathways regulating murine pancreatic development

    DEFF Research Database (Denmark)

    Serup, Palle

    2012-01-01

    The recent decades have seen a huge expansion in our knowledge about pancreatic development. Numerous lineage-restricted transcription factor genes have been identified and much has been learned about their function. Similarly, numerous signaling pathways important for pancreas development have...... been identified and the specific roles have been investigated by genetic and cell biological methods. The present review presents an overview of the principal signaling pathways involved in regulating murine pancreatic growth, morphogenesis, and cell differentiation....

  12. mTOR Hyperactivation in down syndrome hippocampus appears early during development

    NARCIS (Netherlands)

    Iyer, Anand M.; van Scheppingen, Jackelien; Milenkovic, Ivan; Anink, Jasper J.; Adle-Biassette, Homa; Kovacs, Gabor G.; Aronica, Eleonora

    2014-01-01

    The mammalian target of rapamycin (mTOR) signaling pathway is a key developmental pathway involved in mechanisms underlying cellular aging and neurodegeneration. We hypothesized that its deregulation may occur during early brain development in patients with Down syndrome (DS). The expression

  13. Targeting Apoptosis Signaling Pathways for Anticancer Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Fulda, Simone, E-mail: simone.fulda@kgu.de [Institute for Experimental Cancer Research in Pediatrics, Goethe-University, Frankfurt (Germany)

    2011-08-29

    Treatment approaches for cancer, for example chemotherapy, radiotherapy, or immunotherapy, primarily act by inducing cell death in cancer cells. Consequently, the inability to trigger cell death pathways or alternatively, evasion of cancer cells to the induction of cell death pathways can result in resistance of cancers to current treatment protocols. Therefore, in order to overcome treatment resistance a better understanding of the underlying mechanisms that regulate cell death and survival pathways in cancers and in response to cancer therapy is necessary to develop molecular-targeted therapies. This strategy should lead to more effective and individualized treatment strategies that selectively target deregulated signaling pathways in a tumor type- and patient-specific manner.

  14. Targeting Apoptosis Signaling Pathways for Anticancer Therapy

    International Nuclear Information System (INIS)

    Fulda, Simone

    2011-01-01

    Treatment approaches for cancer, for example chemotherapy, radiotherapy, or immunotherapy, primarily act by inducing cell death in cancer cells. Consequently, the inability to trigger cell death pathways or alternatively, evasion of cancer cells to the induction of cell death pathways can result in resistance of cancers to current treatment protocols. Therefore, in order to overcome treatment resistance a better understanding of the underlying mechanisms that regulate cell death and survival pathways in cancers and in response to cancer therapy is necessary to develop molecular-targeted therapies. This strategy should lead to more effective and individualized treatment strategies that selectively target deregulated signaling pathways in a tumor type- and patient-specific manner.

  15. U12, a UDCA derivative, acts as an anti-hepatoma drug lead and inhibits the mTOR/S6K1 and cyclin/CDK complex pathways.

    Directory of Open Access Journals (Sweden)

    Yang Xu

    Full Text Available U12, one of 20 derivatives synthesized from ursodeoxycholic acid (UDCA, has been found to have anticancer effects in liver cancer cell lines (SMMC-7721 and HepG2 and to protect normal liver cells from deoxycholic acid (DCA damage (QSG-7701. Its anticancer mechanism was investigated using computer-aided network pharmacology and comparative proteomics. Results showed that its anti-malignancy activities were activated by mTOR/S6K1, cyclinD1/CDK2/4 and caspase-dependent apoptotic signaling pathways in hepatocellular carcinoma cells (HCC. The action of U12 may be similar to that of rapamycin. Animal testing confirmed that U12 exerted better anti-tumor activity than UDCA and had less severe side effects than fluorouracil (5-Fu. These observations indicate that U12 differs from UDCA and other derivatives and may be a suitable lead for the development of compounds useful in the treatment of HCC.

  16. mTOR Complex Signaling through the SEMA4A-Plexin B2 Axis Is Required for Optimal Activation and Differentiation of CD8+ T Cells.

    Science.gov (United States)

    Ito, Daisuke; Nojima, Satoshi; Nishide, Masayuki; Okuno, Tatsusada; Takamatsu, Hyota; Kang, Sujin; Kimura, Tetsuya; Yoshida, Yuji; Morimoto, Keiko; Maeda, Yohei; Hosokawa, Takashi; Toyofuku, Toshihiko; Ohshima, Jun; Kamimura, Daisuke; Yamamoto, Masahiro; Murakami, Masaaki; Morii, Eiichi; Rakugi, Hiromi; Isaka, Yoshitaka; Kumanogoh, Atsushi

    2015-08-01

    Mammalian target of rapamycin (mTOR) plays crucial roles in activation and differentiation of diverse types of immune cells. Although several lines of evidence have demonstrated the importance of mTOR-mediated signals in CD4(+) T cell responses, the involvement of mTOR in CD8(+) T cell responses is not fully understood. In this study, we show that a class IV semaphorin, SEMA4A, regulates CD8(+) T cell activation and differentiation through activation of mTOR complex (mTORC) 1. SEMA4A(-/-) CD8(+) T cells exhibited impairments in production of IFN-γ and TNF-α and induction of the effector molecules granzyme B, perforin, and FAS-L. Upon infection with OVA-expressing Listeria monocytogenes, pathogen-specific effector CD8(+) T cell responses were significantly impaired in SEMA4A(-/-) mice. Furthermore, SEMA4A(-/-) CD8(+) T cells exhibited reduced mTORC1 activity and elevated mTORC2 activity, suggesting that SEMA4A is required for optimal activation of mTORC1 in CD8(+) T cells. IFN-γ production and mTORC1 activity in SEMA4A(-/-) CD8(+) T cells were restored by administration of recombinant Sema4A protein. In addition, we show that plexin B2 is a functional receptor of SEMA4A in CD8(+) T cells. Collectively, these results not only demonstrate the role of SEMA4A in CD8(+) T cells, but also reveal a novel link between a semaphorin and mTOR signaling. Copyright © 2015 by The American Association of Immunologists, Inc.

  17. Cap-independent translation ensures mTOR expression and function upon protein synthesis inhibition.

    Science.gov (United States)

    Marques-Ramos, Ana; Candeias, Marco M; Menezes, Juliane; Lacerda, Rafaela; Willcocks, Margaret; Teixeira, Alexandre; Locker, Nicolas; Romão, Luísa

    2017-11-01

    The mechanistic/mammalian target of rapamycin (mTOR) is a conserved serine/threonine kinase that integrates cellular signals from the nutrient and energy status to act, namely, on the protein synthesis machinery. While major advances have emerged regarding the regulators and effects of the mTOR signaling pathway, little is known about the regulation of mTOR gene expression. Here, we show that the human mTOR transcript can be translated in a cap-independent manner, and that its 5' untranslated region (UTR) is a highly folded RNA scaffold capable of binding directly to the 40S ribosomal subunit. We further demonstrate that mTOR is able to bypass the cap requirement for translation both in normal and hypoxic conditions. Moreover, our data reveal that the cap-independent translation of mTOR is necessary for its ability to induce cell-cycle progression into S phase. These results suggest a novel regulatory mechanism for mTOR gene expression that integrates the global protein synthesis changes induced by translational inhibitory conditions. © 2017 Marques-Ramos et al.; Published by Cold Spring Harbor Laboratory Press for the RNA Society.

  18. A mouse model of DEPDC5-related epilepsy: Neuronal loss of Depdc5 causes dysplastic and ectopic neurons, increased mTOR signaling, and seizure susceptibility.

    Science.gov (United States)

    Yuskaitis, Christopher J; Jones, Brandon M; Wolfson, Rachel L; Super, Chloe E; Dhamne, Sameer C; Rotenberg, Alexander; Sabatini, David M; Sahin, Mustafa; Poduri, Annapurna

    2018-03-01

    DEPDC5 is a newly identified epilepsy-related gene implicated in focal epilepsy, brain malformations, and Sudden Unexplained Death in Epilepsy (SUDEP). In vitro, DEPDC5 negatively regulates amino acid sensing by the mTOR complex 1 (mTORC1) pathway, but the role of DEPDC5 in neurodevelopment and epilepsy has not been described. No animal model of DEPDC5-related epilepsy has recapitulated the neurological phenotypes seen in patients, and germline knockout rodent models are embryonic lethal. Here, we establish a neuron-specific Depdc5 conditional knockout mouse by cre-recombination under the Synapsin1 promotor. Depdc5 flox/flox -Syn1 Cre (Depdc5cc+) mice survive to adulthood with a progressive neurologic phenotype that includes motor abnormalities (i.e., hind limb clasping) and reduced survival compared to littermate control mice. Depdc5cc+ mice have larger brains with increased cortical neuron size and dysplastic neurons throughout the cortex, comparable to the abnormal neurons seen in human focal cortical dysplasia specimens. Depdc5 results in constitutive mTORC1 hyperactivation exclusively in neurons as measured by the increased phosphorylation of the downstream ribosomal protein S6. Despite a lack of increased mTORC1 signaling within astrocytes, Depdc5cc+ brains show reactive astrogliosis. We observed two Depdc5cc+ mice to have spontaneous seizures, including a terminal seizure. We demonstrate that as a group Depdc5cc+ mice have lowered seizure thresholds, as evidenced by decreased latency to seizures after chemoconvulsant injection and increased mortality from pentylenetetrazole-induced seizures. In summary, our neuron-specific Depdc5 knockout mouse model recapitulates clinical, pathological, and biochemical features of human DEPDC5-related epilepsy and brain malformations. We thereby present an important model in which to study targeted therapeutic strategies for DEPDC5-related conditions. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Gemcitabine resistance in breast cancer cells regulated by PI3K/AKT-mediated cellular proliferation exerts negative feedback via the MEK/MAPK and mTOR pathways

    Directory of Open Access Journals (Sweden)

    Yang XL

    2014-06-01

    Full Text Available Xiao Li Yang, Feng Juan Lin, Ya Jie Guo, Zhi Min Shao, Zhou Luo Ou Key Laboratory of Breast Cancer in Shanghai, Breast Cancer Institute, Cancer Hospital, Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, People's Republic of China Abstract: Chemoresistance is a major cause of cancer treatment failure and leads to a reduction in the survival rate of cancer patients. Phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR and mitogen-activated protein kinase (MAPK pathways are aberrantly activated in many malignant tumors, including breast cancer, which may indicate an association with breast cancer chemoresistance. In this study, we generated a chemoresistant human breast cancer cell line, MDA-MB-231/gemcitabine (simplified hereafter as “231/Gem”, from MDA-MB-231 human breast cancer cells. Flow cytometry studies revealed that with the same treatment concentration of gemcitabine, 231/Gem cells displayed more robust resistance to gemcitabine, which was reflected by fewer apoptotic cells and enhanced percentage of S-phase cells. Through the use of inverted microscopy, Cell Counting Kit-8, and Transwell assays, we found that compared with parental 231 cells, 231/Gem cells displayed more morphologic projections, enhanced cell proliferative ability, and improved cell migration and invasion. Mechanistic studies revealed that the PI3K/AKT/mTOR and mitogen-activated protein kinase kinase (MEK/MAPK signaling pathways were activated through elevated expression of phosphorylated (p-extracellular signal-regulated kinase (ERK, p-AKT, mTOR, p-mTOR, p-P70S6K, and reduced expression of p-P38 and LC3-II (the marker of autophagy in 231/Gem in comparison to control cells. However, there was no change in the expression of Cyclin D1 and p-adenosine monophosphate-activated protein kinase (AMPK. In culture, inhibitors of PI3K/AKT and mTOR, but not of MEK/MAPK, could reverse the enhanced proliferative

  20. Hedgehog signaling pathway in neuroblastoma differentiation.

    Science.gov (United States)

    Souzaki, Ryota; Tajiri, Tatsuro; Souzaki, Masae; Kinoshita, Yoshiaki; Tanaka, Sakura; Kohashi, Kenichi; Oda, Yoshinao; Katano, Mitsuo; Taguchi, Tomoaki

    2010-12-01

    The hedgehog (Hh) signaling pathway is activated in some adult cancers. On the other hand, the Hh signaling pathway plays an important role in the development of the neural crest in embryos. The aim of this study is to show the activation of Hh signaling pathway in neuroblastoma (NB), a pediatric malignancy arising from neural crest cells, and to reveal the meaning of the Hh signaling pathway in NB development. This study analyzed the expression of Sonic hedgehog (Shh), GLI1, and Patched 1 (Ptch1), transactivators of Hh signaling pathway, by immunohistochemistry in 82 NB and 10 ganglioneuroblastoma cases. All 92 cases were evaluated for the status of MYCN amplification. Of the 92 cases, 67 (73%) were positive for Shh, 62 cases (67%) were positive for GLI1, and 73 cases (79%) were positive for Ptch1. Only 2 (10%) of the 20 cases with MYCN amplification were positive for Shh and GLI1, and 4 cases (20%) were positive for Ptch1 (MYCN amplification vs no MYCN amplification, P ≦ .01). The percentage of GLI1-positive cells in the cases with INSS stage 1 without MYCN amplification was significantly higher than that with INSS stage 4. Of 72 cases without MYCN amplification, 60 were GLI1-positive. Twelve cases were GLI1-negative, and the prognosis of the GLI1-positive cases was significantly better than that of the GLI1-negative cases (P = .015). Most of NBs without MYCN amplification were positive for Shh, GLI1, and Ptch1. In the cases without MYCN amplification, the high expression of GLI1 was significantly associated with early clinical stage and a good prognosis of the patients. In contrast to adult cancers, the activation of the Hh signaling pathway in NB may be associated with the differentiation of the NB. Copyright © 2010 Elsevier Inc. All rights reserved.

  1. Novel nervous and multi-system regenerative therapeutic strategies for diabetes mellitus with mTOR

    Directory of Open Access Journals (Sweden)

    Kenneth Maiese

    2016-01-01

    Full Text Available Throughout the globe, diabetes mellitus (DM is increasing in incidence with limited therapies presently available to prevent or resolve the significant complications of this disorder. DM impacts multiple organs and affects all components of the central and peripheral nervous systems that can range from dementia to diabetic neuropathy. The mechanistic target of rapamycin (mTOR is a promising agent for the development of novel regenerative strategies for the treatment of DM. mTOR and its related signaling pathways impact multiple metabolic parameters that include cellular metabolic homeostasis, insulin resistance, insulin secretion, stem cell proliferation and differentiation, pancreatic β-cell function, and programmed cell death with apoptosis and autophagy. mTOR is central element for the protein complexes mTOR Complex 1 (mTORC1 and mTOR Complex 2 (mTORC2 and is a critical component for a number of signaling pathways that involve phosphoinositide 3-kinase (PI 3-K, protein kinase B (Akt, AMP activated protein kinase (AMPK, silent mating type information regulation 2 homolog 1 (Saccharomyces cerevisiae (SIRT1, Wnt1 inducible signaling pathway protein 1 (WISP1, and growth factors. As a result, mTOR represents an exciting target to offer new clinical avenues for the treatment of DM and the complications of this disease. Future studies directed to elucidate the delicate balance mTOR holds over cellular metabolism and the impact of its broad signaling pathways should foster the translation of these targets into effective clinical regimens for DM.

  2. Blocking mammalian target of rapamycin (mTOR) improves neuropathic pain evoked by spinal cord injury.

    Science.gov (United States)

    Wang, Xiaoping; Li, Xiaojia; Huang, Bin; Ma, Shuai

    2016-01-01

    Spinal cord injury (SCI) is an extremely serious type of physical trauma observed in clinics. Neuropathic pain resulting from SCI has a lasting and significant impact on most aspects of daily life. Thus, a better understanding of the molecular pathways responsible for the cause of neuropathic pain observed in SCI is important to develop effective therapeutic agents and treatment strategies. Mammalian target of rapamycin (mTOR) is a serine/threonine protein kinase that is well known for its critical roles in regulating protein synthesis and growth. Furthermore, compelling evidence supports the notion that widespread dysregulation of mTOR and its downstream pathways are involved in neuropathic pain. Thus, in this study we specifically examined the underlying mechanisms by which mTOR and its signaling pathways are involved in SCI-evoked neuropathic pain in a rat model. Overall, we demonstrated that SCI increased the protein expression of p-mTOR, and mTORmediated- phosphorylation of 4E-binding protein 4 (4E-BP1) and p70 ribosomal S6 protein kinase 1 (S6K1) in the superficial dorsal horn of the spinal cord. Also, we showed that blocking spinal mTOR by intrathecal injection of rapamycin significantly inhibited pain responses induced by mechanical and thermal stimulation. In addition, blocking spinal phosphatidylinositide 3-kinase (p-PI3K) pathway significantly attenuated activities of p-mTOR pathways as well as mechanical and thermal hyperalgesia in SCI rats. Moreover, blocking mTOR and PI3K decreased the enhanced levels of substance P and calcitonin gene-related peptide (CGRP) in the dorsal horn of SCI rats. We revealed specific signaling pathways leading to SCI-evoked neuropathic pain, including the activation of PI3K, mTOR and its downstream signaling pathways. Targeting one or more of these signaling molecules may present new opportunities for treatment and management of neuropathic pain often observed in patients with SCI.

  3. AKTivation of the PI3K/AKT/mTOR signaling pathway by KSHV

    Directory of Open Access Journals (Sweden)

    Aadra P Bhatt

    2013-01-01

    Full Text Available As an obligate intracellular parasite, the Kaposi sarcoma-associated herpesvirus (KSHV relies on host cell machinery to meet its needs for survival, viral replication, production, and dissemination of progeny virions. KSHV is a ɣ-herpesvirus that is associated with three different malignancies: Kaposi sarcoma (KS, and two B cell lymphoproliferative disorders, primary effusion lymphoma (PEL and multicentric Castleman disease (MCD. KSHV viral proteins modulate cellular phosphatidylinositol-3-kinase (PI3K/AKT/mammalian target of rapamycin (mTOR signaling pathway, which is a ubiquitous pathway that also controls B lymphocyte proliferation and development. We review the mechanisms by which KSHV manipulates the PI3K/AKT/mTOR pathway, with a specific focus on B cells.

  4. Learning from the Cardiologists and Developing Eluting Stents Targeting the Mtor Pathway for Pulmonary Application; A Future Concept for Tracheal Stenosis

    Science.gov (United States)

    Zarogoulidis, Paul; Darwiche, Kaid; Tsakiridis, Kosmas; Teschler, Helmut; Yarmus, Lonny; Zarogoulidis, Konstantinos; Freitag, Lutz

    2014-01-01

    Tracheal stenosis due to either benign or malignant disease is a situation that the pulmonary physicians and thoracic surgeons have to cope in their everyday clinical practice. In the case where tracheal stenosis is caused due to malignancy mini-interventional interventions with laser, apc, cryoprobe, balloon dilation or with combination of more than one equipment and technique can be used. On the other hand, in the case of a benign disease such as; tracheomalacia the clinician can immediately upon diagnosis proceed to the stent placement. In both situations however; it has been observed that the stents induce formation of granuloma tissue in both or one end of the stent. Therefore a frequent evaluation of the patient is necessary, taking also into account the nature of the primary disease. Evaluation methodologies identifying different types and extent of the trachea stenosis have been previously published. However; we still do not have an effective adjuvant therapy to prevent granuloma tissue formation or prolong already treated granuloma lesions. There have been proposed many mechanisms which induce the abnormal growth of the local tissue, such as; local pressure, local stress, inflammation and vascular endothelial growth factor overexpression. Immunomodulatory agents inhibiting the mTOR pathway are capable of inhibiting the inflammatory cascade locally. In the current mini-review we will try to present the current knowledge of drug eluting stents inhibiting the mTOR pathway and propose a future application of these stents as a local anti-proliferative treatment. PMID:24454525

  5. Learning from the Cardiologists and Developing Eluting Stents Targeting the Mtor Pathway for Pulmonary Application; A Future Concept for Tracheal Stenosis.

    Science.gov (United States)

    Zarogoulidis, Paul; Darwiche, Kaid; Tsakiridis, Kosmas; Teschler, Helmut; Yarmus, Lonny; Zarogoulidis, Konstantinos; Freitag, Lutz

    2013-08-26

    Tracheal stenosis due to either benign or malignant disease is a situation that the pulmonary physicians and thoracic surgeons have to cope in their everyday clinical practice. In the case where tracheal stenosis is caused due to malignancy mini-interventional interventions with laser, apc, cryoprobe, balloon dilation or with combination of more than one equipment and technique can be used. On the other hand, in the case of a benign disease such as; tracheomalacia the clinician can immediately upon diagnosis proceed to the stent placement. In both situations however; it has been observed that the stents induce formation of granuloma tissue in both or one end of the stent. Therefore a frequent evaluation of the patient is necessary, taking also into account the nature of the primary disease. Evaluation methodologies identifying different types and extent of the trachea stenosis have been previously published. However; we still do not have an effective adjuvant therapy to prevent granuloma tissue formation or prolong already treated granuloma lesions. There have been proposed many mechanisms which induce the abnormal growth of the local tissue, such as; local pressure, local stress, inflammation and vascular endothelial growth factor overexpression. Immunomodulatory agents inhibiting the mTOR pathway are capable of inhibiting the inflammatory cascade locally. In the current mini-review we will try to present the current knowledge of drug eluting stents inhibiting the mTOR pathway and propose a future application of these stents as a local anti-proliferative treatment.

  6. Lung cancer, intracellular signaling pathways, and preclinical models

    International Nuclear Information System (INIS)

    Mordant, P.

    2012-01-01

    Non-small cell lung cancer (NSCLC) is the leading cause of cancer-related mortality worldwide. Activation of phosphatidylinositol-3-kinase (PI3K)-AKT and Kirsten rat sarcoma viral oncogene homologue (KRAS) can induce cellular immortalization, proliferation, and resistance to anticancer therapeutics such as epidermal growth factor receptor inhibitors or chemotherapy. This study assessed the consequences of inhibiting these two pathways in tumor cells with activation of KRAS, PI3K-AKT, or both. We investigated whether the combination of a novel RAF/vascular endothelial growth factor receptor inhibitor, RAF265, with a mammalian target of rapamycin (mTOR) inhibitor, RAD001 (everolimus), could lead to enhanced anti-tumoral effects in vitro and in vivo. To address this question, we used cell lines with different status regarding KRAS, PIK3CA, and BRAF mutations, using immunoblotting to evaluate the inhibitors, and MTT and clonogenic assays for effects on cell viability and proliferation. Subcutaneous xenografts were used to assess the activity of the combination in vivo. RAD001 inhibited mTOR downstream signaling in all cell lines, whereas RAF265 inhibited RAF downstream signaling only in BRAF mutant cells. In vitro, addition of RAF265 to RAD001 led to decreased AKT, S6, and Eukaryotic translation initiation factor 4E binding protein 1 phosphorylation in HCT116 cells. In vitro and in vivo, RAD001 addition enhanced the anti-tumoral effect of RAF265 in HCT116 and H460 cells (both KRAS mut, PIK3CA mut); in contrast, the combination of RAF265 and RAD001 yielded no additional activity in A549 and MDAMB231 cells. The combination of RAF and mTOR inhibitors is effective for enhancing anti-tumoral effects in cells with deregulation of both RAS-RAF and PI3K, possibly through the cross-inhibition of 4E binding protein 1 and S6 protein. We then focus on animal models. Preclinical models of NSCLC require better clinical relevance to study disease mechanisms and innovative

  7. A dynamic network model of mTOR signaling reveals TSC-independent mTORC2 regulation

    NARCIS (Netherlands)

    Dalle Pezze, Piero; Sonntag, Annika G; Thien, Antje; Prentzell, Mirja T; Gödel, Markus; Fischer, Sven; Neumann-Haefelin, Elke; Huber, Tobias B; Baumeister, Ralf; Shanley, Daryl P; Thedieck, Kathrin

    2012-01-01

    The kinase mammalian target of rapamycin (mTOR) exists in two multiprotein complexes (mTORC1 and mTORC2) and is a central regulator of growth and metabolism. Insulin activation of mTORC1, mediated by phosphoinositide 3-kinase (PI3K), Akt, and the inhibitory tuberous sclerosis complex 1/2

  8. MTOR-Driven Metabolic Reprogramming Regulates Legionella pneumophila Intracellular Niche Homeostasis

    Science.gov (United States)

    Abshire, Camille F.; Roy, Craig R.

    2016-01-01

    Vacuolar bacterial pathogens are sheltered within unique membrane-bound organelles that expand over time to support bacterial replication. These compartments sequester bacterial molecules away from host cytosolic immunosurveillance pathways that induce antimicrobial responses. The mechanisms by which the human pulmonary pathogen Legionella pneumophila maintains niche homeostasis are poorly understood. We uncovered that the Legionella-containing vacuole (LCV) required a sustained supply of host lipids during expansion. Lipids shortage resulted in LCV rupture and initiation of a host cell death response, whereas excess of host lipids increased LCVs size and housing capacity. We found that lipids uptake from serum and de novo lipogenesis are distinct redundant supply mechanisms for membrane biogenesis in Legionella-infected macrophages. During infection, the metabolic checkpoint kinase Mechanistic Target of Rapamycin (MTOR) controlled lipogenesis through the Serum Response Element Binding Protein 1 and 2 (SREBP1/2) transcription factors. In Legionella-infected macrophages a host-driven response that required the Toll-like receptors (TLRs) adaptor protein Myeloid differentiation primary response gene 88 (Myd88) dampened MTOR signaling which in turn destabilized LCVs under serum starvation. Inactivation of the host MTOR-suppression pathway revealed that L. pneumophila sustained MTOR signaling throughout its intracellular infection cycle by a process that required the upstream regulator Phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K) and one or more Dot/Icm effector proteins. Legionella-sustained MTOR signaling facilitated LCV expansion and inhibition of the PI3K-MTOR-SREPB1/2 axis through pharmacological or genetic interference or by activation of the host MTOR-suppression response destabilized expanding LCVs, which in turn triggered cell death of infected macrophages. Our work identified a host metabolic requirement for LCV homeostasis and demonstrated that L

  9. The Fog signaling pathway: Insights into signaling in morphogenesis

    Science.gov (United States)

    Manning, Alyssa J.; Rogers, Stephen L.

    2014-01-01

    Epithelia form the building blocks of many tissue and organ types. Epithelial cells often form a contiguous 2-dimensional sheet that is held together by strong adhesions. The mechanical properties conferred by these adhesions allow the cells to undergo dramatic three-dimensional morphogenetic movements while maintaining cell–cell contacts during embryogenesis and post-embryonic development. The Drosophila Folded gastrulation pathway triggers epithelial cell shape changes that drive gastrulation and tissue folding and is one of the most extensively studied examples of epithelial morphogenesis. This pathway has yielded key insights into the signaling mechanisms and cellular machinery involved in epithelial remodeling. In this review, we discuss principles of morphogenesis and signaling that have been discovered through genetic and cell biological examination of this pathway. We also consider various regulatory mechanisms and the system's relevance to mammalian development. We propose future directions that will continue to broaden our knowledge of morphogenesis across taxa. PMID:25127992

  10. Transient mTOR inhibition facilitates continuous growth of liver tumors by modulating the maintenance of CD133+ cell populations.

    Directory of Open Access Journals (Sweden)

    Zhaojuan Yang

    Full Text Available The mammalian target of the rapamycin (mTOR pathway, which drives cell proliferation, is frequently hyperactivated in a variety of malignancies. Therefore, the inhibition of the mTOR pathway has been considered as an appropriate approach for cancer therapy. In this study, we examined the roles of mTOR in the maintenance and differentiation of cancer stem-like cells (CSCs, the conversion of conventional cancer cells to CSCs and continuous tumor growth in vivo. In H-Ras-transformed mouse liver tumor cells, we found that pharmacological inhibition of mTOR with rapamycin greatly increased not only the CD133+ populations both in vitro and in vivo but also the expression of stem cell-like genes. Enhancing mTOR activity by over-expressing Rheb significantly decreased CD133 expression, whereas knockdown of the mTOR yielded an opposite effect. In addition, mTOR inhibition severely blocked the differentiation of CD133+ to CD133- liver tumor cells. Strikingly, single-cell culture experiments revealed that CD133- liver tumor cells were capable of converting to CD133+ cells and the inhibition of mTOR signaling substantially promoted this conversion. In serial implantation of tumor xenografts in nude BALB/c mice, the residual tumor cells that were exposed to rapamycin in vivo displayed higher CD133 expression and had increased secondary tumorigenicity compared with the control group. Moreover, rapamycin treatment also enhanced the level of stem cell-associated genes and CD133 expression in certain human liver tumor cell lines, such as Huh7, PLC/PRC/7 and Hep3B. The mTOR pathway is significantly involved in the generation and the differentiation of tumorigenic liver CSCs. These results may be valuable for the design of more rational strategies to control clinical malignant HCC using mTOR inhibitors.

  11. Mammalian target of rapamycin (mTOR): a central regulator of male fertility?

    Science.gov (United States)

    Jesus, Tito T; Oliveira, Pedro F; Sousa, Mário; Cheng, C Yan; Alves, Marco G

    2017-06-01

    Mammalian target of rapamycin (mTOR) is a central regulator of cellular metabolic phenotype and is involved in virtually all aspects of cellular function. It integrates not only nutrient and energy-sensing pathways but also actin cytoskeleton organization, in response to environmental cues including growth factors and cellular energy levels. These events are pivotal for spermatogenesis and determine the reproductive potential of males. Yet, the molecular mechanisms by which mTOR signaling acts in male reproductive system remain a matter of debate. Here, we review the current knowledge on physiological and molecular events mediated by mTOR in testis and testicular cells. In recent years, mTOR inhibition has been explored as a prime strategy to develop novel therapeutic approaches to treat cancer, cardiovascular disease, autoimmunity, and metabolic disorders. However, the physiological consequences of mTOR dysregulation and inhibition to male reproductive potential are still not fully understood. Compelling evidence suggests that mTOR is an arising regulator of male fertility and better understanding of this atypical protein kinase coordinated action in testis will provide insightful information concerning its biological significance in other tissues/organs. We also discuss why a new generation of mTOR inhibitors aiming to be used in clinical practice may also need to include an integrative view on the effects in male reproductive system.

  12. Signaling Pathways in Cardiac Myocyte Apoptosis

    Science.gov (United States)

    Xia, Peng; Liu, Yuening

    2016-01-01

    Cardiovascular diseases, the number 1 cause of death worldwide, are frequently associated with apoptotic death of cardiac myocytes. Since cardiomyocyte apoptosis is a highly regulated process, pharmacological intervention of apoptosis pathways may represent a promising therapeutic strategy for a number of cardiovascular diseases and disorders including myocardial infarction, ischemia/reperfusion injury, chemotherapy cardiotoxicity, and end-stage heart failure. Despite rapid growth of our knowledge in apoptosis signaling pathways, a clinically applicable treatment targeting this cellular process is currently unavailable. To help identify potential innovative directions for future research, it is necessary to have a full understanding of the apoptotic pathways currently known to be functional in cardiac myocytes. Here, we summarize recent progress in the regulation of cardiomyocyte apoptosis by multiple signaling molecules and pathways, with a focus on the involvement of these pathways in the pathogenesis of heart disease. In addition, we provide an update regarding bench to bedside translation of this knowledge and discuss unanswered questions that need further investigation. PMID:28101515

  13. Arctigenin inhibits the activation of the mTOR pathway, resulting in autophagic cell death and decreased ER expression in ER-positive human breast cancer cells.

    Science.gov (United States)

    Maxwell, Thressi; Lee, Kyu Shik; Kim, Soyoung; Nam, Kyung-Soo

    2018-04-01

    Arctigenin, a member of the Asteraceae family, is a biologically active lignan that is consumed worldwide due to its several health benefits. However, its use may pose a problem for patients with estrogen receptor (ER)α-positive breast cancer, since studies have shown that arctigenin is a phytoestrogen that exerts a proliferative effect by binding to the ER. Thus, in this study, we examined the effect of arctigenin on ERα-positive MCF-7 human breast cancer cells to determine whether the consumption of arctigenin is safe for patients with breast cancer. First, we found that arctigenin inhibited the viability of the MCF-7 cells, and colony formation assay confirmed that this effect was cytotoxic rather than cytostatic. The cytotoxic effects were not mediated by cell cycle arrest, apoptosis, or necroptosis, despite DNA damage, as indicated by poly(ADP-ribose) polymerase (PARP) cleavage and phosphorylated H2A.X. An increase in lipidated LC3, a marker of autophagosome formation, was observed, indicating that autophagy was induced by arctigenin, which was found to be triggered by the inhibition of the mechanistic target of rapamycin (mTOR) pathway. We then examined the effects of arctigenin on ERα expression and determined whether it affects the sensitivity of the cells to tamoxifen, as tamoxifen is commonly used against hormone-responsive cancers and is known to act via the ERα. We found that treatment with arctigenin effectively downregulated ERα expression, which was found to be a consequence of the inhibition of the mTOR pathway. However, treatment with arctigenin in combination with tamoxifen did not affect the sensitivity of the cells to tamoxifen, but instead, exerted a synergistic effect. On the whole, our data indicate that the phytoestrogen, arctigenin, mainly targeted the mTOR pathway in ERα-positive MCF-7 human breast cancer cells, leading to autophagy-induced cell death and the downregulation of ERα expression. Furthermore, the synergistic effects

  14. ROLE OF PI3K-AKT-mTOR AND Wnt SIGNALING PATHWAYS IN G1-S TRANSITION OF CELL CYCLE IN CANCER CELLS

    Directory of Open Access Journals (Sweden)

    LAKSHMIPATHI eVADLAKONDA

    2013-04-01

    Full Text Available The PI3K–Akt pathway together with one of its downstream targets, the mechanistic target of rapamycin (mTOR is a highly deregulated pathway in cancers. There is a reciprocal relation between the Akt phosphorylation and mTOR complexes. Akt phosphorylated at T308 activates mTORC1 by inhibition of the tuberous sclerosis complex (TSC1/2, where as mTORC2 is recognized as the kinase that phosphorylates Akt at S473. Recent developments in the research on regulatory mechanisms of autophagy places mTORC1 mediated inhibition of autophagy at the central position in activation of proliferation and survival pathways in cells. Autophagy is a negative regulator of Wnt signaling pathway and the downstream effectors of Wnt signaling pathway, cyclin D1 and the c-Myc, are the key players in initiation of cell cycle and regulation of the G1-S transition in cancer cells. Production of reaction oxygen species (ROS, a common feature of a cancer cell metabolism, activates several downstream targets like the transcription factors FoxO, which play key roles in promoting the progression of cell cycle. A model is presented on the role of PI3K -Akt - mTOR and Wnt pathways in regulation of the progression of cell cycle through Go-G1-and S phases.

  15. Gene targeting by the vitamin D response element binding protein reveals a role for vitamin D in osteoblast mTOR signaling.

    Science.gov (United States)

    Lisse, Thomas S; Liu, Ting; Irmler, Martin; Beckers, Johannes; Chen, Hong; Adams, John S; Hewison, Martin

    2011-03-01

    Transcriptional regulation by hormonal 1,25-dihydroxyvitamin D(3) [1,25(OH)(2)D(3)] involves occupancy of vitamin D response elements (VDREs) by the VDRE binding protein (VDRE-BP) or 1,25(OH)(2)D(3)-bound vitamin D receptor (VDR). This relationship is disrupted by elevated VDRE-BP, causing a form of hereditary vitamin D-resistant rickets (HVDRR). DNA array analysis showed that of 114 genes regulated by 1,25(OH)(2)D(3) in control cells, almost all (113) were rendered insensitive to the hormone in VDRE-BP-overexpressing HVDRR cells. Among these was the gene for DNA-damage-inducible transcript 4 (DDIT4), an inhibitor of mammalian target of rapamycin (mTOR) signaling. Chromatin immunoprecipitation PCR using 1,25(OH)(2)D(3)-treated osteoblasts confirmed that VDR and VDRE-BP compete for binding to the DDIT4 gene promoter. Expression of DDIT4 mRNA in these cells was induced (1.6-6 fold) by 1,25(OH)(2)D(3) (10-100 nM), and Western blot and flow cytometry analysis showed that this response involved suppression of phosphorylated S6K1(T389) (a downstream target of mTOR) similar to rapamycin treatment. siRNA knockdown of DDIT4 completely abrogated antiproliferative responses to 1,25(OH)(2)D(3), whereas overexpression of VDRE-BP exerted a dominant-negative effect on transcription of 1,25(OH)(2)D(3)-target genes. DDIT4, an inhibitor of mTOR signaling, is a direct target for 1,25(OH)(2)D(3) and VDRE-BP, and functions to suppress cell proliferation in response to vitamin D.

  16. Prenatal physical activity and diet composition affect the expression of nutrient transporters and mTOR signaling molecules in the human placenta.

    Science.gov (United States)

    Brett, K E; Ferraro, Z M; Holcik, M; Adamo, K B

    2015-02-01

    Adequate nutrient delivery to the fetus is essential for optimal growth. Differences in prenatal physical activity level and diet quality influence maternal energy balance and these factors may alter placental nutrient transport. We investigated the associations between meeting physical activity guidelines and the quality of maternal diet on the expression of genes involved in fatty acid, amino acid and glucose transport, and mammalian target of rapamycin (mTOR) and insulin signaling in the placenta from 16 term pregnancies. Physical activity was directly measured with accelerometry, diet composition was assessed with 24 h dietary recalls, and gene expression was measured with custom polymerase chain reaction (PCR) arrays. Women who met physical activity guidelines had lower gene expression of fatty acid transport protein 4 (FATP4), insulin-like growth factor 1 (IGF1), and the beta non-catalytic subunit of AMP-activated protein kinase (AMPK), and a higher expression of SNAT2. There was a strong positive correlation observed between total sugar intake and glucose transporter 1 (GLUT1) (r = 0.897, p = 0.000, n = 12), and inverse correlations between total sugar and mTOR and IGF1 expression. Percentage of total calories from protein was inversely related to insulin-like growth factor 1 receptor (IGF1R) (r = -0.605, p = 0.028, n = 13). Variations in maternal physical activity and diet composition altered the expression of genes involved in fatty acid, amino acid and glucose transport and mTOR signaling. Future research on placental nutrient transport should include direct measures of maternal PA and dietary habits to help eliminate confounding factors. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. 14-3-3γ Regulates Lipopolysaccharide-Induced Inflammatory Responses and Lactation in Dairy Cow Mammary Epithelial Cells by Inhibiting NF-κB and MAPKs and Up-Regulating mTOR Signaling

    Directory of Open Access Journals (Sweden)

    Lixin Liu

    2015-07-01

    Full Text Available As a protective factor for lipopolysaccharide (LPS-induced injury, 14-3-3γ has been the subject of recent research. Nevertheless, whether 14-3-3γ can regulate lactation in dairy cow mammary epithelial cells (DCMECs induced by LPS remains unknown. Here, the anti-inflammatory effect and lactation regulating ability of 14-3-3γ in LPS-induced DCMECs are investigated for the first time, and the molecular mechanisms responsible for their effects are explored. The results of qRT-PCR showed that 14-3-3γ overexpression significantly inhibited the mRNA expression of tumor necrosis factor-α (TNF-α, interleukin-6 (IL-6, interleukin-1β (IL-1β and inducible nitric oxide synthase (iNOS. Enzyme-linked immunosorbent assay (ELISA analysis revealed that 14-3-3γ overexpression also suppressed the production of TNF-α and IL-6 in cell culture supernatants. Meanwhile, CASY-TT Analyser System showed that 14-3-3γ overexpression clearly increased the viability and proliferation of cells. The results of kit methods and western blot analysis showed that 14-3-3γ overexpression promoted the secretion of triglycerides and lactose and the synthesis of β-casein. Furthermore, the expression of genes relevant to nuclear factor-κB (NF-κB and mitogen-activated protein kinase (MAPKs and lactation-associated proteins were assessed by western blot, and the results suggested that 14-3-3γ overexpression inactivated the NF-κB and MAPK signaling pathways by down-regulating extracellular signal regulated protein kinase (ERK, p38 mitogen-activated protein kinase (p38MAPK and inhibitor of NF-κB (IκB phosphorylation levels, as well as by inhibiting NF-κB translocation. Meanwhile, 14-3-3γ overexpression enhanced the expression levels of β-casein, mammalian target of rapamycin (mTOR, ribosomal protein S6 kinase 1 (S6K1, serine/threonine protein kinase Akt 1 (AKT1, sterol regulatory element binding protein 1 (SREBP1 and peroxisome proliferator-activated receptor gamma

  18. Purinergic signaling pathways in endocrine system.

    Science.gov (United States)

    Bjelobaba, Ivana; Janjic, Marija M; Stojilkovic, Stanko S

    2015-09-01

    Adenosine-5'-triphosphate is released by neuroendocrine, endocrine, and other cell types and acts as an extracellular agonist for ligand-gated P2X cationic channels and G protein-coupled P2Y receptors in numerous organs and tissues, including the endocrine system. The breakdown of ATP by ectonucleotidases not only terminates its extracellular messenger functions, but also provides a pathway for the generation of two additional agonists: adenosine 5'-diphosphate, acting via some P2Y receptors, and adenosine, a native agonist for G protein-coupled adenosine receptors, also expressed in the endocrine system. This article provides a review of purinergic signaling pathways in the hypothalamic magnocellular neurosecretory cells and neurohypophysis, hypothalamic parvocellular neuroendocrine system, adenohypophysis, and effector glands organized in five axes: hypothalamic-pituitary-gonadal, hypothalamic-pituitary-thyroid, hypothalamic-pituitary-adrenal, hypothalamic-pituitary-growth hormone, and hypothalamic-pituitary-prolactin. We attempted to summarize current knowledge of purinergic receptor subtypes expressed in the endocrine system, including their roles in intracellular signaling, hormone secretion, and other cell functions. We also briefly review the release mechanism for adenosine-5'-triphosphate by neuroendocrine, endocrine and surrounding cells, the enzymes involved in adenosine-5'-triphosphate hydrolysis to adenosine-5'-diphosphate and adenosine, and the relevance of this pathway for sequential activation of receptors and termination of signaling. Published by Elsevier B.V.

  19. Purinergic Signaling Pathways in Endocrine System

    Science.gov (United States)

    Bjelobaba, Ivana; Janjic, Marija M.; Stojilkovic, Stanko S.

    2015-01-01

    Adenosine-5′-triphosphate is released by neuroendocrine, endocrine, and other cell types and acts as an extracellular agonist for ligand-gated P2X cationic channels and G protein-coupled P2Y receptors in numerous organs and tissues, including the endocrine system. The breakdown of ATP by ectonucleotidases not only terminates its extracellular messenger functions, but also provides a pathway for the generation of two additional agonists: adenosine 5′-diphosphate, acting via some P2Y receptors, and adenosine, a native agonist for G protein-coupled adenosine receptors, also expressed in the endocrine system. This article provides a review of purinergic signaling pathways in the hypothalamic magnocellular neurosecretory cells and neurohypophysis, hypothalamic parvocellular neuroendocrine system, adenohypophysis, and effector glands organized in five axes: hypothalamic-pituitary-gonadal, hypothalamic-pituitary-thyroid, hypothalamic-pituitary-adrenal, hypothalamic-pituitary-growth hormone, and hypothalamic-pituitary-prolactin. We attempted to summarize current knowledge of purinergic receptor subtypes expressed in the endocrine system, including their roles in intracellular signaling, hormone secretion, and other cell functions. We also briefly review the release mechanism for adenosine-5′-triphosphate by neuroendocrine, endocrine and surrounding cells, the enzymes involved in adenosine-5′-triphosphate hydrolysis to adenosine-5′-diphosphate and adenosine, and the relevance of this pathway for sequential activation of receptors and termination of signaling. PMID:25960051

  20. Insulin signaling pathways in lepidopteran steroidogenesis

    Directory of Open Access Journals (Sweden)

    Wendy eSmith

    2014-02-01

    Full Text Available Molting and metamorphosis are stimulated by the secretion of ecdysteroid hormones from the prothoracic glands. Insulin-like hormones have been found to enhance prothoracic gland activity, providing a mechanism to link molting to nutritional state. In silk moths (Bombyx mori, the prothoracic glands are directly stimulated by insulin and the insulin-like hormone bombyxin. Further, in Bombyx , the neuropeptide prothoracicotropic hormone (PTTH appears to act at least in part through the insulin-signaling pathway. In the prothoracic glands of Manduca sexta, while insulin stimulates the phosphorylation of the insulin receptor and Akt, neither insulin nor bombyxin II stimulate ecdysone secretion. Involvement of the insulin-signaling pathway in Manduca prothoracic glands was explored using two inhibitors of phosphatidylinositol-3-kinase (PI3K, LY294002 and wortmannin. PI3K inhibitors block the phosphorylation of Akt and 4EBP but have no effect on ecdysone secretion, or on the phosphorylation of the MAPkinase, ERK. Inhibitors that block phosphorylation of ERK, including the MEK inhibitor U0126, and high doses of the RSK inhibitor SL0101, effectively inhibit ecdysone secretion. The results highlight differences between the two lepidopteran insects most commonly used to directly study ecdysteroid secretion. In Bombyx, the PTTH and insulin-signaling pathways intersect; both insulin and PTTH enhance the phosphorylation of Akt and stimulate ecdysteroid secretion, and inhibition of PI3K reduces ecdysteroid secretion. By contrast, in Manduca, the action of PTTH is distinct from insulin. The results highlight species differences in the roles of translational regulators such as 4EBP, and members of the MAPkinase pathway such as ERK and RSK, in the effects of nutritionally-sensitive hormones such as insulin on ecdysone secretion and molting.

  1. TIS21/(BTG2) negatively regulates estradiol-stimulated expansion of hematopoietic stem cells by derepressing Akt phosphorylation and inhibiting mTOR signal transduction.

    Science.gov (United States)

    Kim, Bong Cho; Ryu, Min Sook; Oh, S Paul; Lim, In Kyoung

    2008-09-01

    It has been known that 12-O-tetradecanoyl phorbol-13-acetate-inducible sequence 21 (TIS21), ortholog of human B-cell translocation gene 2, regulates expansions of stage-specific thymocytes and hematopoietic progenitors. In the present study, lineage-negative (Lin(-))/stem cell antigen-1-positive (Sca-1+)/c-Kit+ (LSK) cell content was significantly elevated in bone marrow (BM) of TIS21-knockout (TIS21(-/-)) female mice, suggesting 17beta-estradiol (E(2))-regulated progenitor expansion. E(2) induced DNA synthesis and cell proliferation of mouse embryonic fibroblasts (MEFs) isolated from TIS21(-/-) mice, but not wild type (WT). In contrast to WT, E(2) failed to activate protein kinase B (Akt) in the TIS21(-/-) MEFs, independent of extracellular signal-regulated kinase 1/2 (Erk1/2) activation. Despite attenuation of Akt activation, mammalian target of rapamycin (mTOR) was constitutively activated in the TIS21(-/-) MEFs. Furthermore, mitogen-activated protein kinase 1/2 inhibitor or knockdown of Erk1 could restore activation of Akt and downregulate mTOR. Immunoprecipitation showed Akt preferentially bound to phosphorylated Erk1/2 (p-Erk1/2) in TIS21(-/-) cells, but reconstitution of TIS21 inhibited their interaction. E(2)-injected TIS21(-/-) male mice also increased LSK cells in BM. Taken together, expansion of hematopoietic progenitors in TIS21(-/-) female mice might be through inhibition of Akt activation, and constitutive activation of mTOR via preferential binding of TIS21 to E(2)-induced p-Erk1/2, compared with that of Akt. Our results suggest that TIS21 plays a pivotal role in maintaining the hematopoietic stem cell compartment and hematopoiesis.

  2. Interleukin 4 signals through two related pathways.

    Science.gov (United States)

    Pernis, A; Witthuhn, B; Keegan, A D; Nelms, K; Garfein, E; Ihle, J N; Paul, W E; Pierce, J H; Rothman, P

    1995-08-15

    The interleukin 4 (IL-4) signaling pathway involves activation, by tyrosine phosphorylation, of two distinct substrates, a signal-transducing factor (STF-IL4) and the IL-4-induced phosphotyrosine substrate (4PS). It is not known whether the IL-4-mediated activation of these substrates occurs via related or distinct signaling pathways. We report that 32D cells, an IL-3-dependent myeloid progenitor cell line in which no phosphorylated 4PS is found, activate high levels of STF-IL4 in response to IL-4. Consistent with the known requirement for 4PS or insulin receptor substrate 1 (IRS-1) in IL-4-mediated mitogenesis, activation of STF-IL4 in 32D cells is not sufficient for IL-4-inducible c-myc expression. In addition, we have examined the ability of 32D cells transfected with different truncation mutants of the human IL-4 receptor to activate Jak-3 kinase and STF-IL4 in response to human IL-4. As in the case of 4PS/IRS-1, we have found that activation of both Jak-3 and STF-IL4 requires the presence of the IL-4 receptor region comprising aa 437-557. The finding that the same region of the IL-4 receptor is required for the induction of both 4PS/IRS-1 and STF-IL4 suggests that the IL-4-stimulated activation of these two substrates might involve common factors.

  3. Signaling pathways in a Citrus EST database

    Directory of Open Access Journals (Sweden)

    Angela Mehta

    2007-01-01

    Full Text Available Citrus spp. are economically important crops, which in Brazil are grown mainly in the State of São Paulo. Citrus cultures are attacked by several pathogens, causing severe yield losses. In order to better understand this culture, the Millenium Project (IAC Cordeirópolis was launched in order to sequence Citrus ESTs (expressed sequence tags from different tissues, including leaf, bark, fruit, root and flower. Plants were submitted to biotic and abiotic stresses and investigated under different development stages (adult vs. juvenile. Several cDNA libraries were constructed and the sequences obtained formed the Citrus ESTs database with almost 200,000 sequences. Searches were performed in the Citrus database to investigate the presence of different signaling pathway components. Several of the genes involved in the signaling of sugar, calcium, cytokinin, plant hormones, inositol phosphate, MAPKinase and COP9 were found in the citrus genome and are discussed in this paper. The results obtained may indicate that similar mechanisms described in other plants, such as Arabidopsis, occur in citrus. Further experimental studies must be conducted in order to understand the different signaling pathways present.

  4. Non-Smad pathways in TGF-β signaling

    OpenAIRE

    Zhang, Ying E

    2009-01-01

    Transforming growth factor-β utilizes a multitude of intracellular signaling pathways in addition to Smads to regulate a wide array of cellular functions. These non-canonical, non-Smad pathways are activated directly by ligand-occupied receptors to reinforce, attenuate, or otherwise modulate downstream cellular responses. These non-Smad pathways include various branches of MAP kinase pathways, Rho-like GTPase signaling pathways, and phosphatidylinositol-3-kinase/AKT pathways. This review focu...

  5. Immunohistochemical analysis of the mechanistic target of rapamycin and hypoxia signalling pathways in basal cell carcinoma and trichoepithelioma.

    Directory of Open Access Journals (Sweden)

    Tjinta Brinkhuizen

    Full Text Available BACKGROUND: Basal cell carcinoma (BCC is the most common cancer in Caucasians. Trichoepithelioma (TE is a benign neoplasm that strongly resembles BCC. Both are hair follicle (HF tumours. HFs are hypoxic microenvironments, therefore we hypothesized that hypoxia-induced signalling pathways could be involved in BCC and TE as they are in other human malignancies. Hypoxia-inducible factor 1 (HIF1 and mechanistic/mammalian target of rapamycin (mTOR are key players in these pathways. OBJECTIVES: To determine whether HIF1/mTOR signalling is involved in BCC and TE. METHODS: We used immunohistochemical staining of formalin-fixed paraffin-embedded BCC (n = 45 and TE (n = 35 samples to assess activity of HIF1, mTORC1 and their most important target genes. The percentage positive tumour cells was assessed manually in a semi-quantitative manner and categorized (0%, 80%. RESULTS: Among 45 BCC and 35 TE examined, expression levels were respectively 81% and 57% (BNIP3, 73% and 75% (CAIX, 79% and 86% (GLUT1, 50% and 19% (HIF1α, 89% and 88% (pAKT, 55% and 61% (pS6, 15% and 25% (pMTOR, 44% and 63% (PHD2 and 44% and 49% (VEGF-A. CAIX, Glut1 and PHD2 expression levels were significantly higher in TE when only samples with at least 80% expression were included. CONCLUSIONS: HIF and mTORC1 signalling seems active in both BCC and TE. There are no appreciable differences between the two with respect to pathway activity. At this moment immunohistochemical analyses of HIF, mTORC1 and their target genes does not provide a reliable diagnostic tool for the discrimination of BCC and TE.

  6. Down-Regulation of Homer1b/c Protects Against Chemically Induced Seizures Through Inhibition of mTOR Signaling

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    Lei Cao

    2015-03-01

    Full Text Available Background: Homer is a family of post synaptic density proteins functionally and physically attached to target proteins at proline-rich sequences. Reducing Homer1b/c expression has been shown in previous studies to be protective against excitotoxic insults, implicating Homer1b/c in the physiological regulation of aberrant neuronal excitability. Methods: To test the efficacy of a Homer1b/c reducing therapy for disorders with a detrimental hyperexcitability profile in mice, we used small interfere RNA (siRNA to decrease endogenous Homer1b/c expression in mouse hippocampus. The baseline motor and cognitive behavior was measured by sensorimotor tests, Morris water maze and elevated plus maze tasks. The anti-epileptic effects of Homer1b/c knockdown were determined in two chemically induced seizure models induced by Picrotoxin (PTX or pentylenetetrazole (PTZ administration. Results: The results of sensorimotor tests, Morris water maze and elevated plus maze tasks showed that Homer1b/c reduction had no effect on baseline motor or cognitive behavior. In two chemically induced seizure models, mice with reduced Homerb/c protein had less severe seizures than control mice. Total Homer1b/c protein levels and seizure severity were highly correlated, such that those mice with the most severe seizures also had the highest levels of Homer1b/c. In addition, the phosphorylation of mammalian target of rapamycin (mTOR and its target protein S6 was significantly inhibited in Homer1b/c down-regulated mice. Homer1b/c knockdown-induced inhibition of mTOR pathway was partially ablated by the metabotropic glutamate receptor 5 (mGluR5 agonist CHPG. Conclusion: Our results demonstrate that endogenous Homer1b/c is integral for regulating neuronal hyperexcitability in adult animals and suggest that reduction of Homer1b/c could protect against chemically induced seizures through inhibition mTOR pathway.

  7. Agmatine modulates melanogenesis via MITF signaling pathway.

    Science.gov (United States)

    Kwon, Eun-Jeong; Kim, Moon-Moo

    2017-01-01

    Agmatine contained in soybean is also found in Manaca, an anti-aging plant, inhabited in Amazon and induces vasodilation by the promotion of NO synthesis in blood vessel. However, the research of agmatine on melanin synthesis related to hair greying is lacking. The aim of this study was to investigate the melanogenic effect of agmatine via regulation of MITF signaling pathway in B16F1 cells. It was determined whether agmatine regulates melanin synthesis at cellular level in addition to the effect of agmatine on mushroom tyrosinase in vitro in the presence of different concentrations of agmatine. Furthermore, the effect of agmatine on the protein expressions of tyrosinase, TRP-1, TRP-2, BMP-4, BMP-6, C-KIT, p-p38, MITF and C-FOS were examined by western blot analysis. In addition, immunofluorescence staining was carried out to visualize the location of MITF expression in cell. Agmatine at 256μM or more increased melanin synthesis as well as tyrosinase activity. Moreover, whereas agmatine increased the expression levels of TRP-1, BMP-6, p-p38 and MITF, it reduced the expression level of BMP-4. It was also found that agmatine enhanced the expression level of MITF in nucleus. These results suggest that agmatine could induce melanin synthesis though the regulation of MITF transcription factor via BMP-6/p38 signaling pathway. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Collagen type I induces EGFR-TKI resistance in EGFR-mutated cancer cells by mTOR activation through Akt-independent pathway.

    Science.gov (United States)

    Yamazaki, Shota; Higuchi, Youichi; Ishibashi, Masayuki; Hashimoto, Hiroko; Yasunaga, Masahiro; Matsumura, Yasuhiro; Tsuchihara, Katsuya; Tsuboi, Masahiro; Goto, Koichi; Ochiai, Atsushi; Ishii, Genichiro

    2018-06-01

    Primary resistance to epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) is a serious problem in lung adenocarcinoma patients harboring EGFR mutations. The aim of this study was to examine whether and how collagen type I (Col I), the most abundantly deposited matrix in tumor stroma, affects EGFR-TKI sensitivity in EGFR-mutant cells. We evaluated the EGFR-TKI sensitivity of EGFR-mutated cancer cells cultured with Col I. Changes in the activation of downstream signaling molecules of EGFR were analyzed. We also examined the association between the Col I expression in tumor stroma in surgical specimens and EGFR-TKI response of postoperative recurrence patients with EGFR mutations. Compared to cancer cells without Col I, the survival rate of cancer cells cultured with Col I was significantly higher after EGFR-TKI treatment. In cancer cells cultured with and without Col I, EGFR-TKI suppressed the levels of phosphorylated (p-)EGFR, p-ERK1/2, and p-Akt. When compared to cancer cells without Col I, expression of p-P70S6K, a hallmark of mTOR activation, was dramatically upregulated in cancer cells with Col I. This activation was maintained even after EGFR-TKI treatment. Simultaneous treatment with EGFR-TKI and mTOR inhibitor abrogated Col I-induced resistance to EGFR-TKI. Patients with Col I-rich stroma had a significantly shorter progression-free survival time after EGFR-TKI therapy (238 days vs 404 days; P Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.

  9. DMPD: When signaling pathways collide: positive and negative regulation of toll-likereceptor signal transduction. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 18631453 When signaling pathways collide: positive and negative regulation of toll-...uction. PubmedID 18631453 Title When signaling pathways collide: positive and neg...l) Show When signaling pathways collide: positive and negative regulation of toll-likereceptor signal transd...likereceptor signal transduction. O'Neill LA. Immunity. 2008 Jul 18;29(1):12-20. (.png) (.svg) (.html) (.csm

  10. Effects of the single and combined treatment with dopamine agonist, somatostatin analog and mTOR inhibitors in a human lung carcinoid cell line: an in vitro study.

    Science.gov (United States)

    Pivonello, Claudia; Rousaki, Panagoula; Negri, Mariarosaria; Sarnataro, Maddalena; Napolitano, Maria; Marino, Federica Zito; Patalano, Roberta; De Martino, Maria Cristina; Sciammarella, Concetta; Faggiano, Antongiulio; Rocco, Gaetano; Franco, Renato; Kaltsas, Gregory A; Colao, Annamaria; Pivonello, Rosario

    2017-06-01

    Somatostatin analogues and mTOR inhibitors have been used as medical therapy in lung carcinoids with variable results. No data are available on dopamine agonists as treatment for lung carcinoids. The main aim of the current study was to evaluate the effect of the combined treatment of somatostatin analogue octreotide and the dopamine agonist cabergoline with mTOR inhibitors in an in vitro model of typical lung carcinoids: the NCI-H727 cell line. In NCI-H727 cell line, reverse transcriptase-quantitative polymerase chain reaction and immunofluorescence were assessed to characterize the expression of the somatostatin receptor 2 and 5, dopamine receptor 2 and mTOR pathway components. Fifteen typical lung carcinoids tissue samples have been used for somatostatin receptor 2, dopamine receptor 2, and the main mTOR pathway component p70S6K expression and localization by immunohistochemistry. Cell viability, fluorescence-activated cell sorting analysis and western blot have been assessed to test the pharmacological effects of octreotide, cabergoline and mTOR inhibitors, and to evaluate the activation of specific cell signaling pathways in NCI-H727 cell line. NCI-H727 cell line expressed somatostatin receptor 2, somatostatin receptor 5 and dopamine receptor 2 and all mTOR pathway components at messenger and protein levels. Somatostatin receptor 2, dopamine receptor 2, and p70S6K (non phosphorylated and phosphorylated) proteins were expressed in most typical lung carcinoids tissue samples. Octreotide and cabergoline did not reduce cell viability as single agents but, when combined with mTOR inhibitors, they potentiate mTOR inhibitors effect after long-term exposure, reducing Akt and ERK phosphorylation, mTOR escape mechanisms, and increasing the expression DNA-damage-inducible transcript 4, an mTOR suppressor. In conclusion, the single use of octreotide and cabergoline is not sufficient to block cell viability but the combined approach of these agents with mTOR inhibitors

  11. Regulation of the insulin-Akt signaling pathway and glycolysis during dehydration stress in the African clawed frog Xenopus laevis.

    Science.gov (United States)

    Wu, Cheng-Wei; Tessier, Shannon N; Storey, Kenneth B

    2017-12-01

    Estivation is an adaptive stress response utilized by some amphibians during periods of drought in the summer season. In this study, we examine the regulation of the insulin signaling cascade and glycolysis pathway in the African clawed frog Xenopus laevis during the dehydration stress induced state of estivation. We show that in the brain and heart of X. laevis, dehydration reduces the phosphorylation of the insulin growth factor-1 receptor (IGF-1R), and this is followed by similar reductions in the phosphorylation of the Akt and mechanistic target of rapamycin (mTOR) kinase. Interestingly, phosphorylation levels of IGF-1R and mTOR were not affected in the kidney, and phosphorylation levels of P70S6K and the ribosomal S6 protein were elevated during dehydration stress. Animals under estivation are also susceptible to periods of hypoxia, suggesting that glycolysis may also be affected. We observed that protein levels of many glycolytic enzymes remained unchanged during dehydration; however, the hypoxia response factor-1 alpha (HIF-1α) protein was elevated by greater than twofold in the heart during dehydration. Overall, we provide evidence that shows that the insulin signaling pathway in X. laevis is regulated in a tissue-specific manner during dehydration stress and suggests an important role for this signaling cascade in mediating the estivation response.

  12. DEPTOR-related mTOR suppression is involved in metformin's anti-cancer action in human liver cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Obara, Akio; Fujita, Yoshihito; Abudukadier, Abulizi; Fukushima, Toru; Oguri, Yasuo; Ogura, Masahito; Harashima, Shin-ichi; Hosokawa, Masaya; Inagaki, Nobuya, E-mail: inagaki@metab.kuhp.kyoto-u.ac.jp

    2015-05-15

    Metformin, one of the most commonly used drugs for patients with type 2 diabetes, recently has received much attention regarding its anti-cancer action. It is thought that the suppression of mTOR signaling is involved in metformin's anti-cancer action. Although liver cancer is one of the most responsive types of cancer for reduction of incidence by metformin, the molecular mechanism of the suppression of mTOR in liver remains unknown. In this study, we investigated the mechanism of the suppressing effect of metformin on mTOR signaling and cell proliferation using human liver cancer cells. Metformin suppressed phosphorylation of p70-S6 kinase, and ribosome protein S6, downstream targets of mTOR, and suppressed cell proliferation. We found that DEPTOR, an endogenous substrate of mTOR suppression, is involved in the suppressing effect of metformin on mTOR signaling and cell proliferation in human liver cancer cells. Metformin increases the protein levels of DEPTOR, intensifies binding to mTOR, and exerts a suppressing effect on mTOR signaling. This increasing effect of DEPTOR by metformin is regulated by the proteasome degradation system; the suppressing effect of metformin on mTOR signaling and cell proliferation is in a DEPTOR-dependent manner. Furthermore, metformin exerts a suppressing effect on proteasome activity, DEPTOR-related mTOR signaling, and cell proliferation in an AMPK-dependent manner. We conclude that DEPTOR-related mTOR suppression is involved in metformin's anti-cancer action in liver, and could be a novel target for anti-cancer therapy. - Highlights: • We elucidated a novel pathway of metformin's anti-cancer action in HCC cells. • DEPTOR is involved in the suppressing effect of metformin on mTOR signaling. • Metformin increases DEPTOR protein levels via suppression of proteasome activity. • DEPTOR-related mTOR suppression is involved in metformin's anti-cancer action.

  13. DEPTOR-related mTOR suppression is involved in metformin's anti-cancer action in human liver cancer cells

    International Nuclear Information System (INIS)

    Obara, Akio; Fujita, Yoshihito; Abudukadier, Abulizi; Fukushima, Toru; Oguri, Yasuo; Ogura, Masahito; Harashima, Shin-ichi; Hosokawa, Masaya; Inagaki, Nobuya

    2015-01-01

    Metformin, one of the most commonly used drugs for patients with type 2 diabetes, recently has received much attention regarding its anti-cancer action. It is thought that the suppression of mTOR signaling is involved in metformin's anti-cancer action. Although liver cancer is one of the most responsive types of cancer for reduction of incidence by metformin, the molecular mechanism of the suppression of mTOR in liver remains unknown. In this study, we investigated the mechanism of the suppressing effect of metformin on mTOR signaling and cell proliferation using human liver cancer cells. Metformin suppressed phosphorylation of p70-S6 kinase, and ribosome protein S6, downstream targets of mTOR, and suppressed cell proliferation. We found that DEPTOR, an endogenous substrate of mTOR suppression, is involved in the suppressing effect of metformin on mTOR signaling and cell proliferation in human liver cancer cells. Metformin increases the protein levels of DEPTOR, intensifies binding to mTOR, and exerts a suppressing effect on mTOR signaling. This increasing effect of DEPTOR by metformin is regulated by the proteasome degradation system; the suppressing effect of metformin on mTOR signaling and cell proliferation is in a DEPTOR-dependent manner. Furthermore, metformin exerts a suppressing effect on proteasome activity, DEPTOR-related mTOR signaling, and cell proliferation in an AMPK-dependent manner. We conclude that DEPTOR-related mTOR suppression is involved in metformin's anti-cancer action in liver, and could be a novel target for anti-cancer therapy. - Highlights: • We elucidated a novel pathway of metformin's anti-cancer action in HCC cells. • DEPTOR is involved in the suppressing effect of metformin on mTOR signaling. • Metformin increases DEPTOR protein levels via suppression of proteasome activity. • DEPTOR-related mTOR suppression is involved in metformin's anti-cancer action

  14. DMPD: Regulation of mitochondrial antiviral signaling pathways. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 18549796 Regulation of mitochondrial antiviral signaling pathways. Moore CB, Ting J...P. Immunity. 2008 Jun;28(6):735-9. (.png) (.svg) (.html) (.csml) Show Regulation of mitochondrial antiviral ...signaling pathways. PubmedID 18549796 Title Regulation of mitochondrial antiviral signaling pathways. Author

  15. DMPD: Signaling pathways activated by microorganisms. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 17303405 Signaling pathways activated by microorganisms. Takeuchi O, Akira S. Curr ...Opin Cell Biol. 2007 Apr;19(2):185-91. Epub 2007 Feb 15. (.png) (.svg) (.html) (.csml) Show Signaling pathways activated by microorg...anisms. PubmedID 17303405 Title Signaling pathways activated by microorganisms. Auth

  16. Targeting embryonic signaling pathways in cancer therapy.

    Science.gov (United States)

    Harris, Pamela Jo; Speranza, Giovanna; Dansky Ullmann, Claudio

    2012-01-01

    The embryonic signaling pathways (ESP), Hedgehog, Notch and Wnt, are critical for the regulation of normal stem cells and cellular development processes. They are also activated in the majority of cancers. ESP are operational in putative cancer stem cells (CSC), which drive initial tumorigenesis and sustain cancer progression and recurrence in non-CSC bulk subpopulations. ESP represent novel therapeutic targets. A variety of inhibitors and targeting strategies are being developed. This review discusses the rationale for targeting ESP for cancer treatment, as well as specific inhibitors under development; mainly focusing on those approaching clinical use and the challenges that lie ahead. The data sources utilized are several database search engines (PubMed, Google, Clinicaltrials.gov), and the authors' involvement in the field. CSC research is rapidly evolving. Expectations regarding their therapeutic targeting are rising quickly. Further definition of what constitutes a true CSC, proper validation of CSC markers, a better understanding of cross-talk among ESP and other pathways, and interactions with tumor non-CSC and the tumor microenvironment are needed. The appropriate patient population, the right clinical setting and combination strategies to test these therapies, as well as the proper pharmacodynamic markers to measure, need to be further established.

  17. Leucine Affects α-Amylase Synthesis through PI3K/Akt-mTOR Signaling Pathways in Pancreatic Acinar Cells of Dairy Calves.

    Science.gov (United States)

    Guo, Long; Liang, Ziqi; Zheng, Chen; Liu, Baolong; Yin, Qingyan; Cao, Yangchun; Yao, Junhu

    2018-05-23

    Dietary nutrient utilization, particularly starch, is potentially limited by digestion in dairy cow small intestine because of shortage of α-amylase. Leucine acts as an effective signal molecular in the mTOR signaling pathway, which regulates a series of biological processes, especially protein synthesis. It has been reported that leucine could affect α-amylase synthesis and secretion in ruminant pancreas, but mechanisms have not been elaborated. In this study, pancreatic acinar (PA) cells were used as a model to determine the cellular signal of leucine influence on α-amylase synthesis. PA cells were isolated from newborn Holstein dairy bull calves and cultured in Dulbecco's modifed Eagle's medium/nutrient mixture F12 liquid media containing four leucine treatments (0, 0.23, 0.45, and 0.90 mM, respectively), following α-amylase activity, zymogen granule, and signal pathway factor expression detection. Rapamycin, a specific inhibitor of mTOR, was also applied to PA cells. Results showed that leucine increased ( p synthesis of α-amylase as well as phosphorylation of PI3K, Akt, mTOR, and S6K1 while reduced ( p synthesis. In addition, the extracellular leucine dosage significantly influenced intracellular metabolism of isoleucine ( p synthesis through promoting the PI3K/Akt-mTOR pathway and reducing the GCN2 pathway in PA cells of dairy calves. These pathways form the signaling network that controls the protein synthesis and metabolism. It would be of great interest in future studies to explore the function of leucine in ruminant nutrition.

  18. 20(S-Protopanaxadiol-Induced Apoptosis in MCF-7 Breast Cancer Cell Line through the Inhibition of PI3K/AKT/mTOR Signaling Pathway

    Directory of Open Access Journals (Sweden)

    Hong Zhang

    2018-04-01

    Full Text Available 20(S-Protopanaxadiol (PPD is one of the major active metabolites of ginseng. It has been reported that 20(S-PPD shows a broad spectrum of antitumor effects. Our research study aims were to investigate whether apoptosis of human breast cancer MCF-7 cells could be induced by 20(S-PPD by targeting the Phosphatidylinositol 3-kinase/Protein kinase B/Mammalian target of rapamycin (PI3K/AKT/mTOR signal pathway in vitro and in vivo. Cell cycle analysis was performed by Propidium Iodide (PI staining. To overexpress and knock down the expression of mTOR, pcDNA3.1-mTOR and mTOR small interfering RNA (siRNA transient transfection assays were used, respectively. Cell viability and apoptosis were evaluated by 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide (MTT-test and Annexin V /PI double-staining after transfection. The antitumor effect in vivo was determined by the nude mice xenograft assay. After 24 h of incubation, treatment with 20(S-PPD could upregulate phosphorylated-Phosphatase and tensin homologue deleted on chromosome 10 (p-PTEN expression and downregulate PI3K/AKT/mTOR-pathway protein expression. Moreover, G0/G1 cell cycle arrest in MCF-7 cells could be induced by 20(S-PPD treatment at high concentrations. Furthermore, overexpression or knockdown of mTOR could inhibit or promote the apoptotic effects of 20(S-PPD. In addition, tumor volumes were partially reduced by 20(S-PPD at 100 mg/kg in a MCF-7 xenograft model. Immunohistochemical staining indicated a close relationship between the inhibition of tumor growth and the PI3K/AKT/mTOR signal pathway. PI3K/AKT/mTOR pathway-mediated apoptosis may be one of the potential mechanisms of 20(S-PPD treatment.

  19. The Protective Effects of Κ-Opioid Receptor Stimulation in Hypoxic Pulmonary Hypertension Involve Inhibition of Autophagy Through the AMPK-MTOR Pathway

    Directory of Open Access Journals (Sweden)

    Yaguang Zhou

    2017-12-01

    Full Text Available Background/Aims: In a previous study, we showed that κ-opioid receptor stimulation with the selective agonist U50,488H ameliorated hypoxic pulmonary hypertension (HPH. However, the roles that pulmonary arterial smooth muscle cell (PASMC proliferation, apoptosis, and autophagy play in κ-opioid receptor-mediated protection against HPH are still unknown. The goal of the present study was to investigate the role of autophagy in U50,488H-induced HPH protection and the underlying mechanisms. Methods: Rats were exposed to 10% oxygen for three weeks to induce HPH. After hypoxia, the mean pulmonary arterial pressure (mPAP and the right ventricular pressure (RVP were measured. Cell viability was monitored using the Cell Counting Kit-8 (CCK-8 assay. Cell apoptosis was detected by flow cytometry and Western blot. Autophagy was assessed by means of the mRFP-GFP-LC3 adenovirus transfection assay and by Western blot. Results: Inhibition of autophagy by the administration of chloroquine prevented the development of HPH in the rat model, as evidenced by significantly reduced mPAP and RVP, as well as decreased autophagy. U50,488H mimicked the effects of chloroquine, and the effects of U50,488H were blocked by nor-BNI, a selective κ-opioid receptor antagonist. In vitro experiments showed that the inhibition of autophagy by chloroquine was associated with decreased proliferation and increased apoptosis of PASMCs. Under hypoxia, U50,488H also significantly inhibited autophagy, reduced proliferation and increased apoptosis of PASMCs. These effects of U50,488H were blocked by nor-BNI. Moreover, exposure to hypoxic conditions significantly increased AMPK phosphorylation and reduced mTOR phosphorylation, and these effects were abrogated by U50,488H. The effects of U50,488H on PASMC autophagy were inhibited by AICAR, a selective AMPK agonist, or by rapamycin, a selective mTOR inhibitor. Conclusion: Our data provide evidence for the first time that κ-opioid receptor

  20. Alcohol impairs skeletal muscle protein synthesis and mTOR signaling in a time-dependent manner following electrically stimulated muscle contraction.

    Science.gov (United States)

    Steiner, Jennifer L; Lang, Charles H

    2014-11-15

    Alcohol (EtOH) decreases protein synthesis and mammalian target of rapamycin (mTOR)-mediated signaling and blunts the anabolic response to growth factors in skeletal muscle. The purpose of the current investigation was to determine whether acute EtOH intoxication antagonizes the contraction-induced increase in protein synthesis and mTOR signaling in skeletal muscle. Fasted male mice were injected intraperitoneally with 3 g/kg EtOH or saline (control), and the right hindlimb was electrically stimulated (10 sets of 6 contractions). The gastrocnemius muscle complex was collected 30 min, 4 h, or 12 h after stimulation. EtOH decreased in vivo basal protein synthesis (PS) in the nonstimulated muscle compared with time-matched Controls at 30 min, 4 h, and 12 h. In Control, but not EtOH, PS was decreased 15% after 30 min. In contrast, PS was increased in Control 4 h poststimulation but remained unchanged in EtOH. Last, stimulation increased PS 10% in Control and EtOH at 12 h, even though the absolute rate remained reduced by EtOH. The stimulation-induced increase in the phosphorylation of S6K1 Thr(421)/Ser(424) (20-52%), S6K1 Thr(389) (45-57%), and its substrate rpS6 Ser(240/244) (37-72%) was blunted by EtOH at 30 min, 4 h, and 12 h. Phosphorylation of 4E-BP1 Ser(65) was also attenuated by EtOH (61%) at 4 h. Conversely, phosphorylation of extracellular signal-regulated kinase Thr(202)/Tyr(204) was increased by stimulation in Control and EtOH mice at 30 min but only in Control at 4 h. Our data indicate that acute EtOH intoxication suppresses muscle protein synthesis for at least 12 h and greatly impairs contraction-induced changes in synthesis and mTOR signaling. Copyright © 2014 the American Physiological Society.

  1. Adiponectin promotes VEGF-A-dependent angiogenesis in human chondrosarcoma through PI3K, Akt, mTOR, and HIF-α pathway.

    Science.gov (United States)

    Lee, Hsiang-Ping; Lin, Chih-Yang; Shih, Jhao-Sheng; Fong, Yi-Chin; Wang, Shih-Wei; Li, Te-Mao; Tang, Chih-Hsin

    2015-11-03

    Chondrosarcoma is a type of highly malignant tumor with a potent capacity to invade locally and cause distant metastasis. Adiponectin is a protein hormone secreted predominantly by differentiated adipocytes. On the other hand, angiogenesis is a critical step in tumor growth and metastasis. However, the relationship of adiponectin with vascular endothelial growth factor-A (VEGF-A) expression and angiogenesis in human chondrosarcoma is mostly unknown. In this study we first demonstrated that the expression of adiponectin was correlated with tumor stage of human chondrosarcoma tissues. In addition, we also found that adiponectin increased VEGF-A expression in human chondrosarcoma cells and subsequently induced migration and tube formation in human endothelial progenitor cells (EPCs). Adiponectin promoted VEGF-A expression through adiponectin receptor (AdipoR), phosphoinositide 3 kinase (PI3K), Akt, mammalian target of rapamycin (mTOR), and hypoxia-inducible factor-1α (HIF)-1α signaling cascades. Knockdown of adiponectin decreased VEGF-A expression and also abolished chondrosarcoma conditional medium-mediated tube formation in EPCs in vitro as well as angiogenesis effects in the chick chorioallantoic membrane and Matrigel plug nude mice model in vivo. Therefore, adiponectin is crucial for tumor angiogenesis and growth, which may represent a novel target for anti-angiogenic therapy in human chondrosarcoma.

  2. Discovery and optimization of potent and selective imidazopyridine and imidazopyridazine mTOR inhibitors.

    Science.gov (United States)

    Peterson, Emily A; Boezio, Alessandro A; Andrews, Paul S; Boezio, Christiane M; Bush, Tammy L; Cheng, Alan C; Choquette, Deborah; Coats, James R; Colletti, Adria E; Copeland, Katrina W; DuPont, Michelle; Graceffa, Russell; Grubinska, Barbara; Kim, Joseph L; Lewis, Richard T; Liu, Jingzhou; Mullady, Erin L; Potashman, Michele H; Romero, Karina; Shaffer, Paul L; Stanton, Mary K; Stellwagen, John C; Teffera, Yohannes; Yi, Shuyan; Cai, Ti; La, Daniel S

    2012-08-01

    mTOR is a critical regulator of cellular signaling downstream of multiple growth factors. The mTOR/PI3K/AKT pathway is frequently mutated in human cancers and is thus an important oncology target. Herein we report the evolution of our program to discover ATP-competitive mTOR inhibitors that demonstrate improved pharmacokinetic properties and selectivity compared to our previous leads. Through targeted SAR and structure-guided design, new imidazopyridine and imidazopyridazine scaffolds were identified that demonstrated superior inhibition of mTOR in cellular assays, selectivity over the closely related PIKK family and improved in vivo clearance over our previously reported benzimidazole series. Copyright © 2012. Published by Elsevier Ltd.

  3. Cerebral insulin, insulin signaling pathway, and brain angiogenesis.

    Science.gov (United States)

    Zeng, Yi; Zhang, Le; Hu, Zhiping

    2016-01-01

    Insulin performs unique non-metabolic functions within the brain. Broadly speaking, two major areas of these functions are those related to brain endothelial cells and the blood-brain barrier (BBB) function, and those related to behavioral effects, like cognition in disease states (Alzheimer's disease, AD) and in health. Recent studies showed that both these functions are associated with brain angiogenesis. These findings raise interesting questions such as how they are linked to each other and whether modifying brain angiogenesis by targeting certain insulin signaling pathways could be an effective strategy to treat dementia as in AD, or even to help secure healthy longevity. The two canonical downstream pathways involved in mediating the insulin signaling pathway, the phosphoinositide-3 kinase (PI3K), and mitogen-activated protein kinase (MAPK) cascades, in the brain are supposed to be similar to those in the periphery. PI3K and MAPK pathways play important roles in angiogenesis. Both are involved in stimulating hypoxia inducible factor (HIF) in angiogenesis and could be activated by the insulin signaling pathway. This suggests that PI3K and MAPK pathways might act as cross-talk between the insulin signaling pathway and the angiogenesis pathway in brain. But the cerebral insulin, insulin signaling pathway, and the detailed mechanism in the connection of insulin signaling pathway, brain angiogenesis pathway, and healthy aging or dementias are still mostly not clear and need further studies.

  4. Polyphenolics from mango (Mangifera indica L.) suppress breast cancer ductal carcinoma in situ proliferation through activation of AMPK pathway and suppression of mTOR in athymic nude mice.

    Science.gov (United States)

    Nemec, Matthew J; Kim, Hyemee; Marciante, Alexandria B; Barnes, Ryan C; Hendrick, Erik D; Bisson, William H; Talcott, Stephen T; Mertens-Talcott, Susanne U

    2017-03-01

    The objective of this study was to assess the underlying mechanisms of mango polyphenol decreased cell proliferation and tumor volume in ductal carcinoma in situ breast cancer. We hypothesized that mango polyphenols suppress signaling along the AKT/mTOR axis while up-regulating AMPK. To test this hypothesis, mango polyphenols (0.8 mg gallic acid equivalents per day) and pyrogallol (0.2 mg/day) were administered for 4 weeks to mice xenografted with MCF10DCIS.com cells subcutaneously (n=10 per group). Tumor volumes were significantly decreased, both mango and pyrogallol groups displayed greater than 50% decreased volume compared to control. There was a significant reduction of phosphorylated protein levels of IR, IRS1, IGF-1R, and mTOR by mango; while pyrogallol significantly reduced the phosphorylation levels of IR, IRS1, IGF-1R, p70S6K, and ERK. The protein levels of Sestrin2, which is involved in AMPK-signaling, were significantly elevated in both groups. Also, mango significantly elevated AMPK phosphorylation and pyrogallol significantly elevated LKB1 protein levels. In an in vitro model, mango and pyrogallol increased reactive oxygen species (ROS) generation and arrested cells in S phase. In silico modeling indicates that pyrogallol has the potential to bind directly to the allosteric binding site of AMPK, inducing activation. When AMPK expression was down-regulated using siRNA in vitro, pyrogallol reversed the reduced expression of AMPK. This indicates that pyrogallol not only activates AMPK, but also increases constitutive protein expression. These results suggest that mango polyphenols and their major microbial metabolite, pyrogallol, inhibit proliferation of breast cancer cells through ROS-dependent up-regulation of AMPK and down-regulation of the AKT/mTOR pathway. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. mTOR: A Link from the Extracellular Milieu to Transcriptional Regulation of Oligodendrocyte Development

    Directory of Open Access Journals (Sweden)

    Teresa L. Wood

    2013-02-01

    Full Text Available Oligodendrocyte development is controlled by numerous extracellular signals that regulate a series of transcription factors that promote the differentiation of oligodendrocyte progenitor cells to myelinating cells in the central nervous system. A major element of this regulatory system that has only recently been studied is the intracellular signalling from surface receptors to transcription factors to down-regulate inhibitors and up-regulate inducers of oligodendrocyte differentiation and myelination. The current review focuses on one such pathway: the mTOR (mammalian target of rapamycin pathway, which integrates signals in many cell systems and induces cell responses including cell proliferation and cell differentiation. This review describes the known functions of mTOR as they relate to oligodendrocyte development, and its recently discovered impact on oligodendrocyte differentiation and myelination. A potential model for its role in oligodendrocyte development is proposed.

  6. Metformin sensitizes chemotherapy by targeting cancer stem cells and the mTOR pathway in esophageal cancer

    OpenAIRE

    HONJO, SOICHIRO; AJANI, JAFFER A.; SCOTT, AILING W.; CHEN, QIONGRONG; SKINNER, HEATH D.; STROEHLEIN, JOHN; JOHNSON, RANDY L.; SONG, SHUMEI

    2014-01-01

    Our clinical study indicates esophageal adenocarcinoma patients on metformin had a better treatment response than those without metformin. However, the effects of metformin and the mechanisms of its action in esophageal cancer (EC) are unclear. EC cell lines were used to assess the effects of metformin alone or in combination with 5-fluorouracil on survival and apoptosis. RPPA proteomic array and immunoblots were used to identify signaling affected by metformin. Standard descriptive statistic...

  7. DMPD: Signalling pathways mediating type I interferon gene expression. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 17904888 Signalling pathways mediating type I interferon gene expression. Edwards M...hways mediating type I interferon gene expression. PubmedID 17904888 Title Signalling pathways...R, Slater L, Johnston SL. Microbes Infect. 2007 Sep;9(11):1245-51. Epub 2007 Jul 1. (.png) (.svg) (.html) (.csml) Show Signalling pat

  8. Characteristic mTOR activity in Hodgkin-lymphomas offers a potential therapeutic target in high risk disease – a combined tissue microarray, in vitro and in vivo study

    International Nuclear Information System (INIS)

    Márk, Ágnes; Kopper, László; Sebestyén, Anna; Hajdu, Melinda; Váradi, Zsófia; Sticz, Tamás Béla; Nagy, Noémi; Csomor, Judit; Berczi, Lajos; Varga, Viktória; Csóka, Monika

    2013-01-01

    Targeting signaling pathways is an attractive approach in many malignancies. The PI3K/Akt/mTOR pathway is activated in a number of human neoplasms, accompanied by lower overall and/or disease free survival. mTOR kinase inhibitors have been introduced in the therapy of renal cell carcinoma and mantle cell lymphoma, and several trials are currently underway. However, the pathological characterization of mTOR activity in lymphomas is still incomplete. mTOR activity and the elements of mTOR complexes were investigated by immunohistochemistry on tissue microarrays representing different human non-Hodgkin-lymphomas (81 cases) and Hodgkin-lymphomas (87 cases). The expression of phospho-mTOR, phospho-4EBP1, phospho-p70S6K, phospho-S6, Rictor, Raptor and Bcl-2, Bcl-xL, Survivin and NF-kappaB-p50 were evaluated, and mTOR activity was statistically analyzed along with 5-year survival data. The in vitro and in vivo effect of the mTOR inhibitor rapamycin was also examined in human Hodgkin-lymphoma cell lines. The majority (>50%) of mantle cell lymphoma, Burkitt lymphoma, diffuse large B-cell lymphoma, anaplastic large-cell lymphoma and Hodgkin-lymphoma cases showed higher mTOR activity compared to normal lymphoid tissues. Hodgkin-lymphoma was characterized by high mTOR activity in 93% of the cases, and Bcl-xL and NF-kappaB expression correlated with this mTOR activity. High mTOR activity was observed in the case of both favorable and unfavorable clinical response. Low mTOR activity was accompanied by complete remission and at least 5-year disease free survival in Hodgkin-lymphoma patients. However, statistical analysis did not identify correlation beetween mTOR activity and different clinical data of HL patients, such as survival. We also found that Rictor (mTORC2) was not overexpressed in Hodgkin-lymphoma biopsies and cell lines. Rapamycin inhibited proliferation and induced apoptosis in Hodgkin-lymphoma cells both in vitro and in vivo, moreover, it increased the apoptotic

  9. Antagonism between Hedgehog and Wnt signaling pathways regulates tumorigenicity.

    Science.gov (United States)

    Ding, Mei; Wang, Xin

    2017-12-01

    The crosstalk of multiple cellular signaling pathways is crucial in animal development and tissue homeostasis, and its dysregulation may result in tumor formation and metastasis. The Hedgehog (Hh) and Wnt signaling pathways are both considered to be essential regulators of cell proliferation, differentiation and oncogenesis. Recent studies have indicated that the Hh and Wnt signaling pathways are closely associated and involved in regulating embryogenesis and cellular differentiation. Hh signaling acts upstream of the Wnt signaling pathway, and negative regulates Wnt activity via secreted frizzled-related protein 1 (SFRP1), and the Wnt/β-catenin pathway downregulates Hh activity through glioma-associated oncogene homolog 3 transcriptional regulation. This evidence suggests that the imbalance of Hh and Wnt regulation serves a crucial role in cancer-associated processes. The activation of SFRP1, which inhibits Wnt, has been demonstrated to be an important cross-point between the two signaling pathways. The present study reviews the complex interaction between the Hh and Wnt signaling pathways in embryogenesis and tumorigenicity, and the role of SFRP1 as an important mediator associated with the dysregulation of the Hh and Wnt signaling pathways.

  10. Blocking mammalian target of rapamycin (mTOR improves neuropathic pain evoked by spinal cord injury

    Directory of Open Access Journals (Sweden)

    Wang Xiaoping

    2016-01-01

    Full Text Available Spinal cord injury (SCI is an extremely serious type of physical trauma observed in clinics. Neuropathic pain resulting from SCI has a lasting and significant impact on most aspects of daily life. Thus, a better understanding of the molecular pathways responsible for the cause of neuropathic pain observed in SCI is important to develop effective therapeutic agents and treatment strategies. Mammalian target of rapamycin (mTOR is a serine/threonine protein kinase that is well known for its critical roles in regulating protein synthesis and growth. Furthermore, compelling evidence supports the notion that widespread dysregulation of mTOR and its downstream pathways are involved in neuropathic pain. Thus, in this study we specifically examined the underlying mechanisms by which mTOR and its signaling pathways are involved in SCI-evoked neuropathic pain in a rat model. Overall, we demonstrated that SCI increased the protein expression of p-mTOR, and mTORmediated- phosphorylation of 4E–binding protein 4 (4E-BP1 and p70 ribosomal S6 protein kinase 1 (S6K1 in the superficial dorsal horn of the spinal cord. Also, we showed that blocking spinal mTOR by intrathecal injection of rapamycin significantly inhibited pain responses induced by mechanical and thermal stimulation. In addition, blocking spinal phosphatidylinositide 3-kinase (p-PI3K pathway significantly attenuated activities of p-mTOR pathways as well as mechanical and thermal hyperalgesia in SCI rats. Moreover, blocking mTOR and PI3K decreased the enhanced levels of substance P and calcitonin gene-related peptide (CGRP in the dorsal horn of SCI rats. We revealed specific signaling pathways leading to SCI-evoked neuropathic pain, including the activation of PI3K, mTOR and its downstream signaling pathways. Targeting one or more of these signaling molecules may present new opportunities for treatment and management of neuropathic pain often observed in patients with SCI.

  11. Research advances in Hedgehog signaling pathway in hepatocellular carcinoma

    Directory of Open Access Journals (Sweden)

    LIU Jia

    2015-02-01

    Full Text Available Hedgehog (Hh signaling pathway is present in many animals and plays an important role in regulating embryonic development and differentiation. Aberrant activation of Hh signaling contributes to the pathogenesis of many malignancies. Recent studies have shown that dysregulated Hh signaling pathway participates in the tumorigenesis, tumor invasion, and metastasis of hepatocellular carcinoma (HCC. Investigation of the relationship between Hh signaling pathway and HCC will help elucidate the molecular mechanism of pathogenesis of HCC and provide a new insight into the development of novel anticancer therapy and therapeutic target.

  12. Inositol Hexaphosphate Inhibits Proliferation and Induces Apoptosis of Colon Cancer Cells by Suppressing the AKT/mTOR Signaling Pathway

    Directory of Open Access Journals (Sweden)

    Małgorzata Kapral

    2017-10-01

    Full Text Available Abstract: AKT, a serine/threonine protein kinase and mammalian target of rapamycin (mTOR plays a critical role in the proliferation and resistance to apoptosis that are essential to the development and progression of colon cancer. Therefore, AKT/mTOR signaling pathway has been recognized as an attractive target for anticancer therapy. Inositol hexaphosphate (InsP6, a natural occurring phytochemical, has been shown to have both preventive and therapeutic effects against various cancers, however, its exact molecular mechanisms of action are not fully understood. The aim of the in vitro study was to investigate the anticancer activity of InsP6 on colon cancer with the focus on inhibiting the AKT1 kinase and p70S6K1 as mTOR effector, in relation to proliferation and apoptosis of cells. The colon cancer Caco-2 cells were cultured using standard techniques and exposed to InsP6 at different concentrations (1 mM, 2.5 mM and 5 mM. Cellular proliferative activity was monitored by 5-bromo-2′-deoxyuridine (BrdU incorporation into cellular DNA. Flow cytometric analysis was performed for cell cycle progression and apoptosis studies. Real-time RT-qPCR was used to validate mRNA levels of CDNK1A, CDNK1B, CASP3, CASP9, AKT1 and S6K1 genes. The concentration of p21 protein as well as the activities of caspase 3, AKT1 and p70S6K1 were determined by the ELISA method. The results revealed that IP6 inhibited proliferation and stimulated apoptosis of colon cancer cells. This effect was mediated by an increase in the expression of genes encoding p21, p27, caspase 3, caspase 9 as well a decrease in transcription of AKT1 and S6K1. InsP6 suppressed phosphorylation of AKT1 and p70S6K1, downstream effector of mTOR. Based on these studies it may be concluded that InsP6 can reduce proliferation and induce apoptosis through inhibition of the AKT/mTOR pathway and mTOR effector followed by modulation of the expression and activity of several key components of these pathways in

  13. Pachymic acid promotes induction of autophagy related to IGF-1 signaling pathway in WI-38 cells.

    Science.gov (United States)

    Lee, Su-Gyeong; Kim, Moon-Moo

    2017-12-01

    The insulin-like growth factor 1 (IGF-1) signaling pathway has spotlighted as a mechanism to elucidate aging associated with autophagy in recent years. Therefore, we have tried to screen an effective compound capable of inducing autophagy to delay aging process. The aim of this study is to investigate whether pachymic acid, a main compound in Poria cocos, induces autophagy in the aged cells. The aging of young cells was induced by treatment with IGF-1 at 50 ng/ml three times every two days. The effect of pachymic acid on cell viability was evaluated in human lung fibroblasts, WI-38 cells, using MTT assay. The induction of autophagy was detected using autophagy detection kit. The expression of proteins related to autophagy and IGF-1 signaling pathway was examined by western blot analysis and immunofluorescence assay. In this study, pachymic acid showed cytotoxic effect in a dose dependent manner and remarkably induced autophagy at the same time. Moreover, pachymic acid increased the expression of proteins related to autophagy such as LC3-II and Beclin1 and decreased the levels of mTor phosphorylation and p70S6K in the aged cells. In particular, pachymic acid increased the expression of p-PI3K, p-FoxO and Catalase. In addition, pachymic acid remarkably increased the expression of IGFBP-3. Above results suggest that pachymic acid could induce autophagy related to IGF-1 signaling pathway in the aged cells. Copyright © 2017 Elsevier GmbH. All rights reserved.

  14. Radioresistance-related signaling pathways in nasopharyngeal carcinoma cells

    International Nuclear Information System (INIS)

    Guo Ya; Zhu Xiaodong; Qu Song; Su Fang; Wang Qi; Zhang Wei

    2011-01-01

    Objective: To study the difference of gene expression profile between the radioresistant human nasopharyngeal carcinoma cell line CNE-2R and CNE-2, and to screen the signaling pathway associated with radioresistance of nasopharyngeal carcinoma. Methods: The radioresistant nasopharyngeal carcinoma cell line CNE-2R was constructed from the original cell line CNE-2. CNE-2R and CNE-2 cells were cultured and administered with 60 Co γ-ray irradiation at the dose of 400 cGy for 15 times. Human-6v 3.0 whole genome expression profile was used to screen the differentially expressed genes. Bioinformatic analysis was used to identify the pathways related to radioresistance. Results: The number of the differentially expressed genes that were found in these 2 experiments was 374. The Kegg pathway and Biocarta pathway analysis of the differentially expressed genes showed the biological importance of Toll-like receptor signaling pathway and IL-1 R-mediated signal transduction pathway to the radioresistance of the CNE-2R cells and the significant differences of 13 genes in these 2 pathways,including JUN, MYD88, CCL5, CXCL10, STAT1, LY96, FOS, CCL3, IL-6, IL-8, IL-1α, IL-1β, and IRAK2 (t=13.47-66.57, P<0.05). Conclusions: Toll-like receptor signaling pathway and IL-1R-mediated signal transduction pathway might be related to the occurrence of radioresistance. (authors)

  15. Association of CAD, a multifunctional protein involved in pyrimidine synthesis, with mLST8, a component of the mTOR complexes

    Science.gov (United States)

    2013-01-01

    Background mTOR is a genetically conserved serine/threonine protein kinase, which controls cell growth, proliferation, and survival. A multifunctional protein CAD, catalyzing the initial three steps in de novo pyrimidine synthesis, is regulated by the phosphorylation reaction with different protein kinases, but the relationship with mTOR protein kinase has not been known. Results CAD was recovered as a binding protein with mLST8, a component of the mTOR complexes, from HEK293 cells transfected with the FLAG-mLST8 vector. Association of these two proteins was confirmed by the co-immuoprecipitaiton followed by immunoblot analysis of transfected myc-CAD and FLAG-mLST8 as well as that of the endogenous proteins in the cells. Analysis using mutant constructs suggested that CAD has more than one region for the binding with mLST8, and that mLST8 recognizes CAD and mTOR in distinct ways. The CAD enzymatic activity decreased in the cells depleted of amino acids and serum, in which the mTOR activity is suppressed. Conclusion The results obtained indicate that mLST8 bridges between CAD and mTOR, and plays a role in the signaling mechanism where CAD is regulated in the mTOR pathway through the association with mLST8. PMID:23594158

  16. Evolutionary conservation of plant gibberellin signalling pathway components

    Directory of Open Access Journals (Sweden)

    Reski Ralf

    2007-11-01

    Full Text Available Abstract Background: Gibberellins (GA are plant hormones that can regulate germination, elongation growth, and sex determination. They ubiquitously occur in seed plants. The discovery of gibberellin receptors, together with advances in understanding the function of key components of GA signalling in Arabidopsis and rice, reveal a fairly short GA signal transduction route. The pathway essentially consists of GID1 gibberellin receptors that interact with F-box proteins, which in turn regulate degradation of downstream DELLA proteins, suppressors of GA-controlled responses. Results: Arabidopsis sequences of the gibberellin signalling compounds were used to screen databases from a variety of plants, including protists, for homologues, providing indications for the degree of conservation of the pathway. The pathway as such appears completely absent in protists, the moss Physcomitrella patens shares only a limited homology with the Arabidopsis proteins, thus lacking essential characteristics of the classical GA signalling pathway, while the lycophyte Selaginella moellendorffii contains a possible ortholog for each component. The occurrence of classical GA responses can as yet not be linked with the presence of homologues of the signalling pathway. Alignments and display in neighbour joining trees of the GA signalling components confirm the close relationship of gymnosperms, monocotyledonous and dicotyledonous plants, as suggested from previous studies. Conclusion: Homologues of the GA-signalling pathway were mainly found in vascular plants. The GA signalling system may have its evolutionary molecular onset in Physcomitrella patens, where GAs at higher concentrations affect gravitropism and elongation growth.

  17. Association between PI3K/Akt/mTOR/p70S6K signaling pathway and hepatic fibrosis

    Directory of Open Access Journals (Sweden)

    WU Changhui

    2015-11-01

    Full Text Available Phosphoinositide 3-kinase (PI3K/protein kinase-B (AkT/mammalian target of rapamycin (mTOR/70-kDa ribosomal protein S6 kinase (p70S6K, PI3K/Akt/mTOR/p70S6K, is an important signaling pathway in the life activities of cells, and it plays an important role in promoting the growth, proliferation, invasion, and anti-apoptosis of cells and promoting angiogenesis. It was clarified that the PI3K/Akt/mTOR/p70S6K signaling pathway is involved in regulating the activities of hepatic stellate cell(HSC, thus influencing the development and progression of hepatic fibrosis. Analysis demonstrated that blocking any target of the PI3K/Akt/mTOR/p70S6K signaling pathway can inhibit the activation and proliferation of HSC, promote the apoptosis of HSC, inhibit the extracellular matrix secretion from HSC, and delay the progression of hepatic fibrosis. Blocking the pathway is expected to be a treatment strategy for hepatic fibrosis.

  18. Differential control of ageing and lifespan by isoforms and splice variants across the mTOR network.

    Science.gov (United States)

    Razquin Navas, Patricia; Thedieck, Kathrin

    2017-07-15

    Ageing can be defined as the gradual deterioration of physiological functions, increasing the incidence of age-related disorders and the probability of death. Therefore, the term ageing not only reflects the lifespan of an organism but also refers to progressive functional impairment and disease. The nutrient-sensing kinase mTOR (mammalian target of rapamycin) is a major determinant of ageing. mTOR promotes cell growth and controls central metabolic pathways including protein biosynthesis, autophagy and glucose and lipid homoeostasis. The concept that mTOR has a crucial role in ageing is supported by numerous reports on the lifespan-prolonging effects of the mTOR inhibitor rapamycin in invertebrate and vertebrate model organisms. Dietary restriction increases lifespan and delays ageing phenotypes as well and mTOR has been assigned a major role in this process. This may suggest a causal relationship between the lifespan of an organism and its metabolic phenotype. More than 25 years after mTOR's discovery, a wealth of metabolic and ageing-related effects have been reported. In this review, we cover the current view on the contribution of the different elements of the mTOR signalling network to lifespan and age-related metabolic impairment. We specifically focus on distinct roles of isoforms and splice variants across the mTOR network. The comprehensive analysis of mouse knockout studies targeting these variants does not support a tight correlation between lifespan prolongation and improved metabolic phenotypes and questions the strict causal relationship between them. © 2017 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

  19. Intricacies of hedgehog signaling pathways: A perspective in tumorigenesis

    International Nuclear Information System (INIS)

    Kar, Swayamsiddha; Deb, Moonmoon; Sengupta, Dipta; Shilpi, Arunima; Bhutia, Sujit Kumar; Patra, Samir Kumar

    2012-01-01

    The hedgehog (HH) signaling pathway is a crucial negotiator of developmental proceedings in the embryo governing a diverse array of processes including cell proliferation, differentiation, and tissue patterning. The overall activity of the pathway is significantly curtailed after embryogenesis as well as in adults, yet it retains many of its functional capacities. However, aberration in HH signaling mediates the initiation, proliferation and continued sustenance of malignancy in different tissues to varying degrees through different mechanisms. In this review, we provide an overview of the role of constitutively active aberrant HH signaling pathway in different types of human cancer and the underlying molecular and genetic mechanisms that drive tumorigenesis in that particular tissue. An insight into the various modes of anomalous HH signaling in different organs will provide a comprehensive knowledge of the pathway in these tissues and open a window for individually tailored, tissue-specific therapeutic interventions. The synergistic cross talking of HH pathway with many other regulatory molecules and developmentally inclined signaling pathways may offer many avenues for pharmacological advances. Understanding the molecular basis of abnormal HH signaling in cancer will provide an opportunity to inhibit the deregulated pathway in many aggressive and therapeutically challenging cancers where promising options are not available.

  20. Intricacies of hedgehog signaling pathways: A perspective in tumorigenesis

    Energy Technology Data Exchange (ETDEWEB)

    Kar, Swayamsiddha; Deb, Moonmoon; Sengupta, Dipta; Shilpi, Arunima; Bhutia, Sujit Kumar [Epigenetics and Cancer Research Laboratory, Biochemistry and Molecular Biology Group, Department of Life Science, National Institute of Technology, Rourkela, Odisha 769008 (India); Patra, Samir Kumar, E-mail: samirp@nitrkl.ac.in [Epigenetics and Cancer Research Laboratory, Biochemistry and Molecular Biology Group, Department of Life Science, National Institute of Technology, Rourkela, Odisha 769008 (India)

    2012-10-01

    The hedgehog (HH) signaling pathway is a crucial negotiator of developmental proceedings in the embryo governing a diverse array of processes including cell proliferation, differentiation, and tissue patterning. The overall activity of the pathway is significantly curtailed after embryogenesis as well as in adults, yet it retains many of its functional capacities. However, aberration in HH signaling mediates the initiation, proliferation and continued sustenance of malignancy in different tissues to varying degrees through different mechanisms. In this review, we provide an overview of the role of constitutively active aberrant HH signaling pathway in different types of human cancer and the underlying molecular and genetic mechanisms that drive tumorigenesis in that particular tissue. An insight into the various modes of anomalous HH signaling in different organs will provide a comprehensive knowledge of the pathway in these tissues and open a window for individually tailored, tissue-specific therapeutic interventions. The synergistic cross talking of HH pathway with many other regulatory molecules and developmentally inclined signaling pathways may offer many avenues for pharmacological advances. Understanding the molecular basis of abnormal HH signaling in cancer will provide an opportunity to inhibit the deregulated pathway in many aggressive and therapeutically challenging cancers where promising options are not available.

  1. Implication of inflammatory signaling pathways in obesity-induced insulin resistance

    Directory of Open Access Journals (Sweden)

    Jean-François eTANTI

    2013-01-01

    Full Text Available Obesity is characterized by the development of a low-grade chronic inflammatory state in different metabolic tissues including adipose tissue and liver. This inflammation develops in response to an excess of nutrient flux and is now recognized as an important link between obesity and insulin resistance. Several dietary factors like saturated fatty acids and glucose as well as changes in gut microbiota have been proposed as triggers of this metabolic inflammation through the activation of pattern-recognition receptors, including Toll-like receptors, inflammasome and NOD. The consequences are the production of pro-inflammatory cytokines and the recruitment of immune cells such as macrophages and T lymphocytes in metabolic tissues. Inflammatory cytokines activate several kinases like IKKbeta, mTOR/S6 kinase and MAP kinases as well as SOCS proteins that interfere with insulin signaling and action in adipocytes and hepatocytes. In this review, we summarize recent studies demonstrating that pattern recognition receptors and stress kinases are important integrators of metabolic and inflammatory stress signals in metabolic tissues leading to peripheral and central insulin resistance and metabolic dysfunction. We discuss recent data obtained with genetically modified mice and pharmacological approaches suggesting that these inflammatory pathways are potential novel pharmacological targets for the management of obesity-associated insulin resistance.

  2. Cellular Signaling Pathway Alterations and Potential Targeted Therapies for Medullary Thyroid Carcinoma

    Directory of Open Access Journals (Sweden)

    Serena Giunti

    2013-01-01

    Full Text Available Parafollicular C-cell-derived medullary thyroid cancer (MTC comprises 3% to 4% of all thyroid cancers. While cytotoxic treatments have been shown to have limited efficacy, targeted molecular therapies that inhibit rearranged during transfection (RET and other tyrosine kinase receptors that are mainly involved in angiogenesis have shown great promise in the treatment of metastatic or locally advanced MTC. Multi-tyrosine kinase inhibitors such as vandetanib, which is already approved for the treatment of progressive MTC, and cabozantinib have shown distinct advantages with regard to rates of disease response and control. However, these types of tyrosine kinase inhibitor compounds are able to concurrently block several types of targets, which limits the understanding of RET as a specific target. Moreover, important resistances to tyrosine kinase inhibitors can occur, which limit the long-term efficacy of these treatments. Deregulated cellular signaling pathways and genetic alterations in MTC, particularly the activation of the RAS/mammalian target of rapamycin (mTOR cascades and RET crosstalk signaling, are now emerging as novel and potentially promising therapeutic treatments for aggressive MTC.

  3. Transforming growth factor β-induced expression of chondroitin sulfate proteoglycans is mediated through non-Smad signaling pathways.

    Science.gov (United States)

    Jahan, Naima; Hannila, Sari S

    2015-01-01

    The expression of chondroitin sulfate proteoglycans (CSPGs) by reactive astrocytes is a major factor contributing to glial scarring and regenerative failure after spinal cord injury, but the molecular mechanisms underlying CSPG expression remain largely undefined. One contributing factor is transforming growth factor β (TGFβ), which is upregulated after injury and has been shown to induce expression of CSPGs in vitro. TGFβ typically mediates its effects through the Smad2/3 signaling pathway, and it has been suggested that this pathway is responsible for CSPG expression. However, there is evidence that TGFβ can also activate non-Smad signaling pathways. In this study, we report that TGFβ-induced expression of three different CSPGs--neurocan, brevican, and aggrecan--is mediated through non-Smad signaling pathways. We observed significant increases in TGFβ-induced expression of neurocan, brevican, and aggrecan following siRNA knockdown of Smad2 or Smad4, which indicates that Smad signaling is not required for the expression of these CSPGs. In addition, we show that neurocan, aggrecan, and brevican levels are significantly reduced when TGFβ is administered in the presence of either the PI3K inhibitor LY294002 or the mTOR inhibitor rapamycin, but not the MEK1/2 inhibitor U0126. This suggests that TGFβ mediates this effect through non-Smad-dependent activation of the PI3K-Akt-mTOR signaling pathway, and targeting this pathway may therefore be an effective means of reducing CSPG expression in the injured CNS. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. Role of the Akt/mTOR signaling pathway in human papillomavirus-associated nasal and sinonasal inverted papilloma.

    Science.gov (United States)

    Liu, Yongliang; Duan, Lihua; Tian, Jie; Song, Daoliang; Zhang, Min; Zhao, Shenlin; Yin, Zhaofu; Xiang, Xinxin; Li, Xuezhong

    2017-12-01

    Nasal and sinonasal inverted papilloma (NSIP) is a benign tumor in which surface epithelial cells grow downward into the underlying supportive tissue with varying degrees of metaplasia. Human papillomavirus (HPV) has been proposed as the causal agent in the pathogenesis of this disease. Many studies have shown that HPV can activate the Akt/mechanistic target of rapamycin (mTOR) signaling pathway, but the role of this pathway in HPV-associated NSIP is largely unknown. In this study, we enrolled 40 control tissue samples and 80 NSIP tissue samples. HPV genotyping showed that 47 of the 80 examined cases of NSIP were HPV-positive (58.8%), and the most common subtype was HPV11 (20/53, 37.7%). The immunohistochemistry showed statistically significant differences in phosphorylated Akt and phosphorylated S6 ribosomal protein staining among control samples, HPV-positive NSIP and HPV-negative NSIP. The HPV11 L1-L2 plasmid increased the proliferation of normal human nasopharyngeal epithelial NP69-SV40T cells and human nasopharyngeal cancer CNE1 cells. Meanwhile, rapamycin, an mTOR inhibitor, reversed the increased cell proliferation induced by the HPV11 L1-L2 plasmid. Western blot analysis showed that Akt/mTOR/S6 were overexpressed in NP69-SV40T cells and CNE1 cells infected with the HPV11 L1-L2 plasmid. These data demonstrate that HPV promotes cell proliferation through the Akt/mTOR signaling pathway in NSIP. © The Author 2017. Published by Oxford University Press on behalf of the Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  5. Insights into significance of combined inhibition of MEK and m-TOR signalling output in KRAS mutant non-small-cell lung cancer.

    Science.gov (United States)

    Broutin, Sophie; Stewart, Adam; Thavasu, Parames; Paci, Angelo; Bidart, Jean-Michel; Banerji, Udai

    2016-08-23

    We aimed to understand the dependence of MEK and m-TOR inhibition in EGFR(WT)/ALK(non-rearranged) NSCLC cell lines. In a panel of KRAS(M) and KRAS(WT) NSCLC cell lines, we determined growth inhibition (GI) following maximal reduction in p-ERK and p-S6RP caused by trametinib (MEK inhibitor) and AZD2014 (m-TOR inhibitor), respectively. GI caused by maximal m-TOR inhibition was significantly greater than GI caused by maximal MEK inhibition in the cell line panel (52% vs 18%, PTOR compared with maximal m-TOR+MEK inhibition. However, GI caused by the combination was significantly greater in the KRAS(M) cell lines (79% vs 61%, P=0.017). m-TOR inhibition was more critical to GI than MEK inhibition in EGFR(WT)/ALK(non-rearranged) NSCLC cells. The combination of MEK and m-TOR inhibition was most effective in KRAS(M) cells.

  6. Dissection of the insulin signaling pathway via quantitative phosphoproteomics

    DEFF Research Database (Denmark)

    Krüger, Marcus; Kratchmarova, Irina; Blagoev, Blagoy

    2008-01-01

    spectrum of the tyrosine phosphorylation cascade, we have defined the tyrosine-phosphoproteome of the insulin signaling pathway, using high resolution mass spectrometry in combination with phosphotyrosine immunoprecipitation and stable isotope labeling by amino acids in cell culture (SILAC......The insulin signaling pathway is of pivotal importance in metabolic diseases, such as diabetes, and in cellular processes, such as aging. Insulin activates a tyrosine phosphorylation cascade that branches to create a complex network affecting multiple biological processes. To understand the full...

  7. Signaling Pathways in Pathogenesis of Diamond Blackfan Anemia

    Science.gov (United States)

    2015-12-01

    AWARD NUMBER: W81XWH-12-1-0590 TITLE: SIGNALING PATHWAYS IN PATHOGENESIS OF DIAMOND BLACKFAN ANEMIA PRINCIPAL INVESTIGATOR: KATHLEEN M...SUBTITLE 5a. CONTRACT NUMBER W81XWH-12-1-0590 SIGNALING PATHWAYS IN PATHOGENESIS OF DIAMOND BLACKFAN ANEMIA 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER...Unlimited 13. SUPPLEMENTARY NOTES None 14. ABSTRACT: Diamond Blackfan Anemia (DBA) is a disorder that results in pure red cell aplasia, congenital

  8. mTOR up-regulation of PFKFB3 is essential for acute myeloid leukemia cell survival

    International Nuclear Information System (INIS)

    Feng, Yonghuai; Wu, Liusong

    2017-01-01

    Although mTOR (mammalian target of rapamycin) activation is frequently observed in acute myeloid leukemia (AML) patients, the precise function and the downstream targets of mTOR are poorly understood. Here we revealed that PFKFB3, but not PFKFB1, PFKFB2 nor PFKFB4 was a novel downstream substrate of mTOR signaling pathway as PFKFB3 level was augmented after knocking down TSC2 in THP1 and OCI-AML3 cells. Importantly, PFKFB3 silencing suppressed glycolysis and cell proliferation of TSC2 silencing OCI-AML3 cells and activated apoptosis pathway. These results suggested that mTOR up-regulation of PFKFB3 was essential for AML cells survival. Mechanistically, Rapamycin treatment or Raptor knockdown reduced the expression of PFKFB3 in TSC2 knockdown cells, while Rictor silencing did not have such effect. Furthermore, we also revealed that mTORC1 up-regulated PFKFB3 was dependent on hypoxia-inducible factor 1α (HIF1α), a positive regulator of glycolysis. Moreover, PFKFB3 inhibitor PFK15 and rapamycin synergistically blunted the AML cell proliferation. Taken together, PFKFB3 was a promising drug target in AML patients harboring mTOR hyper-activation.

  9. Modelling and Analysis of Biochemical Signalling Pathway Cross-talk

    Directory of Open Access Journals (Sweden)

    Robin Donaldson

    2010-02-01

    Full Text Available Signalling pathways are abstractions that help life scientists structure the coordination of cellular activity. Cross-talk between pathways accounts for many of the complex behaviours exhibited by signalling pathways and is often critical in producing the correct signal-response relationship. Formal models of signalling pathways and cross-talk in particular can aid understanding and drive experimentation. We define an approach to modelling based on the concept that a pathway is the (synchronising parallel composition of instances of generic modules (with internal and external labels. Pathways are then composed by (synchronising parallel composition and renaming; different types of cross-talk result from different combinations of synchronisation and renaming. We define a number of generic modules in PRISM and five types of cross-talk: signal flow, substrate availability, receptor function, gene expression and intracellular communication. We show that Continuous Stochastic Logic properties can both detect and distinguish the types of cross-talk. The approach is illustrated with small examples and an analysis of the cross-talk between the TGF-b/BMP, WNT and MAPK pathways.

  10. Oncogenic Signaling Pathways in The Cancer Genome Atlas

    NARCIS (Netherlands)

    Sanchez-Vega, Francisco; Mina, Marco; Armenia, Joshua; Chatila, Walid K.; Luna, Augustin; La, Konnor C.; Dimitriadoy, Sofia; Liu, David L.; Kantheti, Havish S.; Saghafinia, Sadegh; Chakravarty, Debyani; Daian, Foysal; Gao, Qingsong; Bailey, Matthew H.; Liang, Wen Wei; Foltz, Steven M.; Shmulevich, Ilya; Ding, Li; Heins, Zachary J.; Ochoa, Angelica; Gross, Benjamin E.; Gao, Jianjiong; Zhang, Hongxin; Kundra, Ritika; Kandoth, Cyriac; Bahceci, Istemi; Dervishi, Leonard; Dogrusoz, Ugur; Zhou, Wanding; Shen, Hui; Laird, Peter W.; Way, Gregory P.; Greene, Casey S.; Liang, Han; Xiao, Yonghong; Wang, Chen; Iavarone, Antonio; Berger, Alice H.; Bivona, Trever G.; Lazar, Alexander J.; Hammer, Gary D.; Giordano, Thomas; Kwong, Lawrence N.; McArthur, Grant; Huang, Chenfei; Tward, Aaron D.; Frederick, Mitchell J.; McCormick, Frank; Meyerson, Matthew; Caesar-Johnson, Samantha J.; Demchok, John A.; Felau, Ina; Kasapi, Melpomeni; Ferguson, Martin L.; Hutter, Carolyn M.; Sofia, Heidi J.; Tarnuzzer, Roy; Wang, Zhining; Yang, Liming; Zenklusen, Jean C.; Zhang, Jiashan (Julia); Chudamani, Sudha; Liu, Jia; Lolla, Laxmi; Naresh, Rashi; Pihl, Todd; Sun, Qiang; Wan, Yunhu; Wu, Ye; Cho, Juok; DeFreitas, Timothy; Frazer, Scott; Gehlenborg, Nils; Getz, Gad; Heiman, David I.; Kim, Jaegil; Lawrence, Michael S.; Lin, Pei; Meier, Sam; Noble, Michael S.; Saksena, Gordon; Voet, Doug; Zhang, Hailei; Bernard, Brady; Chambwe, Nyasha; Dhankani, Varsha; Knijnenburg, Theo; Kramer, Roger; Leinonen, Kalle; Liu, Yuexin; Miller, Michael; Reynolds, Sheila; Shmulevich, Ilya; Thorsson, Vesteinn; Zhang, Wei; Akbani, Rehan; Broom, Bradley M.; Hegde, Apurva M.; Ju, Zhenlin; Kanchi, Rupa S.; Korkut, Anil; Li, Jun; Liang, Han; Ling, Shiyun; Liu, Wenbin; Lu, Yiling; Mills, Gordon B.; Ng, Kwok Shing; Rao, Arvind; Ryan, Michael; Wang, Jing; Weinstein, John N.; Zhang, Jiexin; Abeshouse, Adam; Armenia, Joshua; Chakravarty, Debyani; Chatila, Walid K.; de Bruijn, Ino; Gao, Jianjiong; Gross, Benjamin E.; Heins, Zachary J.; Kundra, Ritika; La, Konnor; Ladanyi, Marc; Luna, Augustin; Nissan, Moriah G.; Ochoa, Angelica; Phillips, Sarah M.; Reznik, Ed; Sanchez-Vega, Francisco; Sander, Chris; Schultz, Nikolaus; Sheridan, Robert; Sumer, S. Onur; Sun, Yichao; Taylor, Barry S.; Wang, Jioajiao; Zhang, Hongxin; Anur, Pavana; Peto, Myron; Spellman, Paul; Benz, Christopher; Stuart, Joshua M.; Wong, Christopher K.; Yau, Christina; Hayes, D. Neil; Parker, Joel S.; Wilkerson, Matthew D.; Ally, Adrian; Balasundaram, Miruna; Bowlby, Reanne; Brooks, Denise; Carlsen, Rebecca; Chuah, Eric; Dhalla, Noreen; Holt, Robert; Jones, Steven J.M.; Kasaian, Katayoon; Lee, Darlene; Ma, Yussanne; Marra, Marco A.; Mayo, Michael; Moore, Richard A.; Mungall, Andrew J.; Mungall, Karen; Robertson, A. Gordon; Sadeghi, Sara; Schein, Jacqueline E.; Sipahimalani, Payal; Tam, Angela; Thiessen, Nina; Tse, Kane; Wong, Tina; Berger, Ashton C.; Beroukhim, Rameen; Cherniack, Andrew D.; Cibulskis, Carrie; Gabriel, Stacey B.; Gao, Galen F.; Ha, Gavin; Meyerson, Matthew; Schumacher, Steven E.; Shih, Juliann; Kucherlapati, Melanie H.; Kucherlapati, Raju S.; Baylin, Stephen; Cope, Leslie; Danilova, Ludmila; Bootwalla, Moiz S.; Lai, Phillip H.; Maglinte, Dennis T.; Van Den Berg, David J.; Weisenberger, Daniel J.; Auman, J. Todd; Balu, Saianand; Bodenheimer, Tom; Fan, Cheng; Hoadley, Katherine A.; Hoyle, Alan P.; Jefferys, Stuart R.; Jones, Corbin D.; Meng, Shaowu; Mieczkowski, Piotr A.; Mose, Lisle E.; Perou, Amy H.; Perou, Charles M.; Roach, Jeffrey; Shi, Yan; Simons, Janae V.; Skelly, Tara; Soloway, Matthew G.; Tan, Donghui; Veluvolu, Umadevi; Fan, Huihui; Hinoue, Toshinori; Laird, Peter W.; Shen, Hui; Zhou, Wanding; Bellair, Michelle; Chang, Kyle; Covington, Kyle; Creighton, Chad J.; Dinh, Huyen; Doddapaneni, Harsha Vardhan; Donehower, Lawrence A.; Drummond, Jennifer; Gibbs, Richard A.; Glenn, Robert; Hale, Walker; Han, Yi; Hu, Jianhong; Korchina, Viktoriya; Lee, Sandra; Lewis, Lora; Li, Wei; Liu, Xiuping; Morgan, Margaret; Morton, Donna; Muzny, Donna; Santibanez, Jireh; Sheth, Margi; Shinbrot, Eve; Wang, Linghua; Wang, Min; Wheeler, David A.; Xi, Liu; Zhao, Fengmei; Hess, Julian; Appelbaum, Elizabeth L.; Bailey, Matthew; Cordes, Matthew G.; Ding, Li; Fronick, Catrina C.; Fulton, Lucinda A.; Fulton, Robert S.; Kandoth, Cyriac; Mardis, Elaine R.; McLellan, Michael D.; Miller, Christopher A.; Schmidt, Heather K.; Wilson, Richard K.; Crain, Daniel; Curley, Erin; Gardner, Johanna; Lau, Kevin; Mallery, David; Morris, Scott; Paulauskis, Joseph; Penny, Robert; Shelton, Candace; Shelton, Troy; Sherman, Mark; Thompson, Eric; Yena, Peggy; Bowen, Jay; Gastier-Foster, Julie M.; Gerken, Mark; Leraas, Kristen M.; Lichtenberg, Tara M.; Ramirez, Nilsa C.; Wise, Lisa; Zmuda, Erik; Corcoran, Niall; Costello, Tony; Hovens, Christopher; Carvalho, Andre L.; de Carvalho, Ana C.; Fregnani, José H.; Longatto-Filho, Adhemar; Reis, Rui M.; Scapulatempo-Neto, Cristovam; Silveira, Henrique C.S.; Vidal, Daniel O.; Burnette, Andrew; Eschbacher, Jennifer; Hermes, Beth; Noss, Ardene; Singh, Rosy; Anderson, Matthew L.; Castro, Patricia D.; Ittmann, Michael; Huntsman, David; Kohl, Bernard; Le, Xuan; Thorp, Richard; Andry, Chris; Duffy, Elizabeth R.; Lyadov, Vladimir; Paklina, Oxana; Setdikova, Galiya; Shabunin, Alexey; Tavobilov, Mikhail; McPherson, Christopher; Warnick, Ronald; Berkowitz, Ross; Cramer, Daniel; Feltmate, Colleen; Horowitz, Neil; Kibel, Adam; Muto, Michael; Raut, Chandrajit P.; Malykh, Andrei; Barnholtz-Sloan, Jill S.; Barrett, Wendi; Devine, Karen; Fulop, Jordonna; Ostrom, Quinn T.; Shimmel, Kristen; Wolinsky, Yingli; Sloan, Andrew E.; De Rose, Agostino; Giuliante, Felice; Goodman, Marc; Karlan, Beth Y.; Hagedorn, Curt H.; Eckman, John; Harr, Jodi; Myers, Jerome; Tucker, Kelinda; Zach, Leigh Anne; Deyarmin, Brenda; Hu, Hai; Kvecher, Leonid; Larson, Caroline; Mural, Richard J.; Somiari, Stella; Vicha, Ales; Zelinka, Tomas; Bennett, Joseph; Iacocca, Mary; Rabeno, Brenda; Swanson, Patricia; Latour, Mathieu; Lacombe, Louis; Têtu, Bernard; Bergeron, Alain; McGraw, Mary; Staugaitis, Susan M.; Chabot, John; Hibshoosh, Hanina; Sepulveda, Antonia; Su, Tao; Wang, Timothy; Potapova, Olga; Voronina, Olga; Desjardins, Laurence; Mariani, Odette; Roman-Roman, Sergio; Sastre, Xavier; Stern, Marc Henri; Cheng, Feixiong; Signoretti, Sabina; Berchuck, Andrew; Bigner, Darell; Lipp, Eric; Marks, Jeffrey; McCall, Shannon; McLendon, Roger; Secord, Angeles; Sharp, Alexis; Behera, Madhusmita; Brat, Daniel J.; Chen, Amy; Delman, Keith; Force, Seth; Khuri, Fadlo; Magliocca, Kelly; Maithel, Shishir; Olson, Jeffrey J.; Owonikoko, Taofeek; Pickens, Alan; Ramalingam, Suresh; Shin, Dong M.; Sica, Gabriel; Van Meir, Erwin G.; Zhang, Hongzheng; Eijckenboom, Wil; Gillis, Ad; Korpershoek, Esther; Looijenga, Leendert; Oosterhuis, Wolter; Stoop, Hans; van Kessel, Kim E.; Zwarthoff, Ellen C.; Calatozzolo, Chiara; Cuppini, Lucia; Cuzzubbo, Stefania; DiMeco, Francesco; Finocchiaro, Gaetano; Mattei, Luca; Perin, Alessandro; Pollo, Bianca; Chen, Chu; Houck, John; Lohavanichbutr, Pawadee; Hartmann, Arndt; Stoehr, Christine; Stoehr, Robert; Taubert, Helge; Wach, Sven; Wullich, Bernd; Kycler, Witold; Murawa, Dawid; Wiznerowicz, Maciej; Chung, Ki; Edenfield, W. Jeffrey; Martin, Julie; Baudin, Eric; Bubley, Glenn; Bueno, Raphael; De Rienzo, Assunta; Richards, William G.; Kalkanis, Steven; Mikkelsen, Tom; Noushmehr, Houtan; Scarpace, Lisa; Girard, Nicolas; Aymerich, Marta; Campo, Elias; Giné, Eva; Guillermo, Armando López; Van Bang, Nguyen; Hanh, Phan Thi; Phu, Bui Duc; Tang, Yufang; Colman, Howard; Evason, Kimberley; Dottino, Peter R.; Martignetti, John A.; Gabra, Hani; Juhl, Hartmut; Akeredolu, Teniola; Stepa, Serghei; Hoon, Dave; Ahn, Keunsoo; Kang, Koo Jeong; Beuschlein, Felix; Breggia, Anne; Birrer, Michael; Bell, Debra; Borad, Mitesh; Bryce, Alan H.; Castle, Erik; Chandan, Vishal; Cheville, John; Copland, John A.; Farnell, Michael; Flotte, Thomas; Giama, Nasra; Ho, Thai; Kendrick, Michael; Kocher, Jean Pierre; Kopp, Karla; Moser, Catherine; Nagorney, David; O'Brien, Daniel; O'Neill, Brian Patrick; Patel, Tushar; Petersen, Gloria; Que, Florencia; Rivera, Michael; Roberts, Lewis; Smallridge, Robert; Smyrk, Thomas; Stanton, Melissa; Thompson, R. Houston; Torbenson, Michael; Yang, Ju Dong; Zhang, Lizhi; Brimo, Fadi; Ajani, Jaffer A.; Gonzalez, Ana Maria Angulo; Behrens, Carmen; Bondaruk, Jolanta; Broaddus, Russell; Czerniak, Bogdan; Esmaeli, Bita; Fujimoto, Junya; Gershenwald, Jeffrey; Guo, Charles; Lazar, Alexander J.; Logothetis, Christopher; Meric-Bernstam, Funda; Moran, Cesar; Ramondetta, Lois; Rice, David; Sood, Anil; Tamboli, Pheroze; Thompson, Timothy; Troncoso, Patricia; Tsao, Anne; Wistuba, Ignacio; Carter, Candace; Haydu, Lauren; Hersey, Peter; Jakrot, Valerie; Kakavand, Hojabr; Kefford, Richard; Lee, Kenneth; Long, Georgina; Mann, Graham; Quinn, Michael; Saw, Robyn; Scolyer, Richard; Shannon, Kerwin; Spillane, Andrew; Stretch, Jonathan; Synott, Maria; Thompson, John; Wilmott, James; Al-Ahmadie, Hikmat; Chan, Timothy A.; Ghossein, Ronald; Gopalan, Anuradha; Levine, Douglas A.; Reuter, Victor; Singer, Samuel; Singh, Bhuvanesh; Tien, Nguyen Viet; Broudy, Thomas; Mirsaidi, Cyrus; Nair, Praveen; Drwiega, Paul; Miller, Judy; Smith, Jennifer; Zaren, Howard; Park, Joong Won; Hung, Nguyen Phi; Kebebew, Electron; Linehan, W. Marston; Metwalli, Adam R.; Pacak, Karel; Pinto, Peter A.; Schiffman, Mark; Schmidt, Laura S.; Vocke, Cathy D.; Wentzensen, Nicolas; Worrell, Robert; Yang, Hannah; Moncrieff, Marc; Goparaju, Chandra; Melamed, Jonathan; Pass, Harvey; Botnariuc, Natalia; Caraman, Irina; Cernat, Mircea; Chemencedji, Inga; Clipca, Adrian; Doruc, Serghei; Gorincioi, Ghenadie; Mura, Sergiu; Pirtac, Maria; Stancul, Irina; Tcaciuc, Diana; Albert, Monique; Alexopoulou, Iakovina; Arnaout, Angel; Bartlett, John; Engel, Jay; Gilbert, Sebastien; Parfitt, Jeremy; Sekhon, Harman; Thomas, George; Rassl, Doris M.; Rintoul, Robert C.; Bifulco, Carlo; Tamakawa, Raina; Urba, Walter; Hayward, Nicholas; Timmers, Henri; Antenucci, Anna; Facciolo, Francesco; Grazi, Gianluca; Marino, Mirella; Merola, Roberta; de Krijger, Ronald; Gimenez-Roqueplo, Anne Paule; Piché, Alain; Chevalier, Simone; McKercher, Ginette; Birsoy, Kivanc; Barnett, Gene; Brewer, Cathy; Farver, Carol; Naska, Theresa; Pennell, Nathan A.; Raymond, Daniel; Schilero, Cathy; Smolenski, Kathy; Williams, Felicia; Morrison, Carl; Borgia, Jeffrey A.; Liptay, Michael J.; Pool, Mark; Seder, Christopher W.; Junker, Kerstin; Omberg, Larsson; Dinkin, Mikhail; Manikhas, George; Alvaro, Domenico; Bragazzi, Maria Consiglia; Cardinale, Vincenzo; Carpino, Guido; Gaudio, Eugenio; Chesla, David; Cottingham, Sandra; Dubina, Michael; Moiseenko, Fedor; Dhanasekaran, Renumathy; Becker, Karl Friedrich; Janssen, Klaus Peter; Slotta-Huspenina, Julia; Abdel-Rahman, Mohamed H.; Aziz, Dina; Bell, Sue; Cebulla, Colleen M.; Davis, Amy; Duell, Rebecca; Elder, J. Bradley; Hilty, Joe; Kumar, Bahavna; Lang, James; Lehman, Norman L.; Mandt, Randy; Nguyen, Phuong; Pilarski, Robert; Rai, Karan; Schoenfield, Lynn; Senecal, Kelly; Wakely, Paul; Hansen, Paul; Lechan, Ronald; Powers, James; Tischler, Arthur; Grizzle, William E.; Sexton, Katherine C.; Kastl, Alison; Henderson, Joel; Porten, Sima; Waldmann, Jens; Fassnacht, Martin; Asa, Sylvia L.; Schadendorf, Dirk; Couce, Marta; Graefen, Markus; Huland, Hartwig; Sauter, Guido; Schlomm, Thorsten; Simon, Ronald; Tennstedt, Pierre; Olabode, Oluwole; Nelson, Mark; Bathe, Oliver; Carroll, Peter R.; Chan, June M.; Disaia, Philip; Glenn, Pat; Kelley, Robin K.; Landen, Charles N.; Phillips, Joanna; Prados, Michael; Simko, Jeffry; Smith-McCune, Karen; VandenBerg, Scott; Roggin, Kevin; Fehrenbach, Ashley; Kendler, Ady; Sifri, Suzanne; Steele, Ruth; Jimeno, Antonio; Carey, Francis; Forgie, Ian; Mannelli, Massimo; Carney, Michael; Hernandez, Brenda; Campos, Benito; Herold-Mende, Christel; Jungk, Christin; Unterberg, Andreas; von Deimling, Andreas; Bossler, Aaron; Galbraith, Joseph; Jacobus, Laura; Knudson, Michael; Knutson, Tina; Ma, Deqin; Milhem, Mohammed; Sigmund, Rita; Godwin, Andrew K.; Madan, Rashna; Rosenthal, Howard G.; Adebamowo, Clement; Adebamowo, Sally N.; Boussioutas, Alex; Beer, David; Giordano, Thomas; Mes-Masson, Anne Marie; Saad, Fred; Bocklage, Therese; Landrum, Lisa; Mannel, Robert; Moore, Kathleen; Moxley, Katherine; Postier, Russel; Walker, Joan; Zuna, Rosemary; Feldman, Michael; Valdivieso, Federico; Dhir, Rajiv; Luketich, James; Pinero, Edna M.Mora; Quintero-Aguilo, Mario; Carlotti, Carlos Gilberto; Dos Santos, Jose Sebastião; Kemp, Rafael; Sankarankuty, Ajith; Tirapelli, Daniela; Catto, James; Agnew, Kathy; Swisher, Elizabeth; Creaney, Jenette; Robinson, Bruce; Shelley, Carl Simon; Godwin, Eryn M.; Kendall, Sara; Shipman, Cassaundra; Bradford, Carol; Carey, Thomas; Haddad, Andrea; Moyer, Jeffey; Peterson, Lisa; Prince, Mark; Rozek, Laura; Wolf, Gregory; Bowman, Rayleen; Fong, Kwun M.; Yang, Ian; Korst, Robert; Rathmell, W. Kimryn; Fantacone-Campbell, J. Leigh; Hooke, Jeffrey A.; Kovatich, Albert J.; Shriver, Craig D.; DiPersio, John; Drake, Bettina; Govindan, Ramaswamy; Heath, Sharon; Ley, Timothy; Van Tine, Brian; Westervelt, Peter; Rubin, Mark A.; Lee, Jung Il; Aredes, Natália D.; Mariamidze, Armaz; Van Allen, Eliezer M.; Cherniack, Andrew D.; Ciriello, Giovanni; Sander, Chris; Schultz, Nikolaus

    2018-01-01

    Genetic alterations in signaling pathways that control cell-cycle progression, apoptosis, and cell growth are common hallmarks of cancer, but the extent, mechanisms, and co-occurrence of alterations in these pathways differ between individual tumors and tumor types. Using mutations, copy-number

  11. Cell volume homeostatic mechanisms: effectors and signalling pathways

    DEFF Research Database (Denmark)

    Hoffmann, E K; Pedersen, Stine Helene Falsig

    2011-01-01

    . Later work addressed the mechanisms through which cellular signalling pathways regulate the volume regulatory effectors or flux pathways. These studies were facilitated by the molecular identification of most of the relevant channels and transporters, and more recently also by the increased...

  12. Review of Signaling Pathways Governing MSC Osteogenic and Adipogenic Differentiation

    Directory of Open Access Journals (Sweden)

    Aaron W. James

    2013-01-01

    Full Text Available Mesenchymal stem cells (MSC are multipotent cells, functioning as precursors to a variety of cell types including adipocytes, osteoblasts, and chondrocytes. Between osteogenic and adipogenic lineage commitment and differentiation, a theoretical inverse relationship exists, such that differentiation towards an osteoblast phenotype occurs at the expense of an adipocytic phenotype. This balance is regulated by numerous, intersecting signaling pathways that converge on the regulation of two main transcription factors: peroxisome proliferator-activated receptor-γ (PPARγ and Runt-related transcription factor 2 (Runx2. These two transcription factors, PPARγ and Runx2, are generally regarded as the master regulators of adipogenesis and osteogenesis. This review will summarize signaling pathways that govern MSC fate towards osteogenic or adipocytic differentiation. A number of signaling pathways follow the inverse balance between osteogenic and adipogenic differentiation and are generally proosteogenic/antiadipogenic stimuli. These include β-catenin dependent Wnt signaling, Hedgehog signaling, and NELL-1 signaling. However, other signaling pathways exhibit more context-dependent effects on adipogenic and osteogenic differentiation. These include bone morphogenic protein (BMP signaling and insulin growth factor (IGF signaling, which display both proosteogenic and proadipogenic effects. In summary, understanding those factors that govern osteogenic versus adipogenic MSC differentiation has significant implications in diverse areas of human health, from obesity to osteoporosis to regenerative medicine.

  13. Anchoring Proteins as Regulators of Signaling Pathways

    Science.gov (United States)

    Perino, Alessia; Ghigo, Alessandra; Scott, John D.; Hirsch, Emilio

    2012-01-01

    Spatial and temporal organization of signal transduction is coordinated through the segregation of signaling enzymes in selected cellular compartments. This highly evolved regulatory mechanism ensures the activation of selected enzymes only in the vicinity of their target proteins. In this context, cAMP-responsive triggering of protein kinase A is modulated by a family of scaffold proteins referred to as A-kinase anchoring proteins. A-kinase anchoring proteins form the core of multiprotein complexes and enable simultaneous but segregated cAMP signaling events to occur in defined cellular compartments. In this review we will focus on the description of A-kinase anchoring protein function in the regulation of cardiac physiopathology. PMID:22859670

  14. Linking proteins to signaling pathways for experiment design and evaluation.

    Directory of Open Access Journals (Sweden)

    Illés J Farkas

    Full Text Available Biomedical experimental work often focuses on altering the functions of selected proteins. These changes can hit signaling pathways, and can therefore unexpectedly and non-specifically affect cellular processes. We propose PathwayLinker, an online tool that can provide a first estimate of the possible signaling effects of such changes, e.g., drug or microRNA treatments. PathwayLinker minimizes the users' efforts by integrating protein-protein interaction and signaling pathway data from several sources with statistical significance tests and clear visualization. We demonstrate through three case studies that the developed tool can point out unexpected signaling bias in normal laboratory experiments and identify likely novel signaling proteins among the interactors of known drug targets. In our first case study we show that knockdown of the Caenorhabditis elegans gene cdc-25.1 (meant to avoid progeny may globally affect the signaling system and unexpectedly bias experiments. In the second case study we evaluate the loss-of-function phenotypes of a less known C. elegans gene to predict its function. In the third case study we analyze GJA1, an anti-cancer drug target protein in human, and predict for this protein novel signaling pathway memberships, which may be sources of side effects. Compared to similar services, a major advantage of PathwayLinker is that it drastically reduces the necessary amount of manual literature searches and can be used without a computational background. PathwayLinker is available at http://PathwayLinker.org. Detailed documentation and source code are available at the website.

  15. Evaluation of Notch and Hypoxia Signaling Pathways in Chemically ...

    African Journals Online (AJOL)

    Hepatocellular carcinoma (HCC) is a common worldwide malignancy. Notch signaling pathway contributes to the genesis of diverse cancers, however, its role in HCC is unclear. Hypoxia is a common feature of HCC. Signal integration between Notch and hypoxia may be involved in HCC. The aim of this study was to ...

  16. DMPD: TLR signaling. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 2007 Feb 1. (.png) (.svg) (.html) (.csml) Show TLR signaling. PubmedID 17275323 Title TLR signaling. Author...s Kawai T, Akira S. Publication Semin Immunol. 2007 Feb;19(1):24-32. Epub 2007 Feb 1. Pathway - PNG File (.png) SVG File (.svg) HTML... File (.html) CSML File (.csml) Open .csml file with CIOP

  17. Signal Transduction Pathways that Regulate CAB Gene Expression

    Energy Technology Data Exchange (ETDEWEB)

    Chory, Joanne

    2004-12-31

    The process of chloroplast differentiation, involves the coordinate regulation of many nuclear and chloroplast genes. The cues for the initiation of this developmental program are both extrinsic (e.g., light) and intrinsic (cell-type and plastid signals). During this project period, we utilized a molecular genetic approach to select for Arabidopsis mutants that did not respond properly to environmental light conditions, as well as mutants that were unable to perceive plastid damage. These latter mutants, called gun mutants, define two retrograde signaling pathways that regulate nuclear gene expression in response to chloroplasts. A major finding was to identify a signal from chloroplasts that regulates nuclear gene transcription. This signal is the build-up of Mg-Protoporphyrin IX, a key intermediate of the chlorophyll biosynthetic pathway. The signaling pathways downstream of this signal are currently being studied. Completion of this project has provided an increased understanding of the input signals and retrograde signaling pathways that control nuclear gene expression in response to the functional state of chloroplasts. These studies should ultimately influence our abilities to manipulate plant growth and development, and will aid in the understanding of the developmental control of photosynthesis.

  18. Signal Transduction Pathways that Regulate CAB Gene Expression

    Energy Technology Data Exchange (ETDEWEB)

    Chory, Joanne

    2006-01-16

    The process of chloroplast differentiation, involves the coordinate regulation of many nuclear and chloroplast genes. The cues for the initiation of this developmental program are both extrinsic (e.g., light) and intrinsic (cell-type and plastid signals). During this project period, we utilized a molecular genetic approach to select for Arabidopsis mutants that did not respond properly to environmental light conditions, as well as mutants that were unable to perceive plastid damage. These latter mutants, called gun mutants, define two retrograde signaling pathways that regulate nuclear gene expression in response to chloroplasts. A major finding was to identify a signal from chloroplasts that regulates nuclear gene transcription. This signal is the build-up of Mg-Protoporphyrin IX, a key intermediate of the chlorophyll biosynthetic pathway. The signaling pathways downstream of this signal are currently being studied. Completion of this project has provided an increased understanding of the input signals and retrograde signaling pathways that control nuclear gene expression in response to the functional state of chloroplasts. These studies should ultimately influence our abilities to manipulate plant growth and development, and will aid in the understanding of the developmental control of photosynthesis.

  19. Signaling pathway networks mined from human pituitary adenoma proteomics data

    Directory of Open Access Journals (Sweden)

    Zhan Xianquan

    2010-04-01

    Full Text Available Abstract Background We obtained a series of pituitary adenoma proteomic expression data, including protein-mapping data (111 proteins, comparative proteomic data (56 differentially expressed proteins, and nitroproteomic data (17 nitroproteins. There is a pressing need to clarify the significant signaling pathway networks that derive from those proteins in order to clarify and to better understand the molecular basis of pituitary adenoma pathogenesis and to discover biomarkers. Here, we describe the significant signaling pathway networks that were mined from human pituitary adenoma proteomic data with the Ingenuity pathway analysis system. Methods The Ingenuity pathway analysis system was used to analyze signal pathway networks and canonical pathways from protein-mapping data, comparative proteomic data, adenoma nitroproteomic data, and control nitroproteomic data. A Fisher's exact test was used to test the statistical significance with a significance level of 0.05. Statistical significant results were rationalized within the pituitary adenoma biological system with literature-based bioinformatics analyses. Results For the protein-mapping data, the top pathway networks were related to cancer, cell death, and lipid metabolism; the top canonical toxicity pathways included acute-phase response, oxidative-stress response, oxidative stress, and cell-cycle G2/M transition regulation. For the comparative proteomic data, top pathway networks were related to cancer, endocrine system development and function, and lipid metabolism; the top canonical toxicity pathways included mitochondrial dysfunction, oxidative phosphorylation, oxidative-stress response, and ERK/MAPK signaling. The nitroproteomic data from a pituitary adenoma were related to cancer, cell death, lipid metabolism, and reproductive system disease, and the top canonical toxicity pathways mainly related to p38 MAPK signaling and cell-cycle G2/M transition regulation. Nitroproteins from a

  20. Epilepsy and the Wnt Signaling Pathway

    Science.gov (United States)

    2015-06-01

    forebrain development. The primary target is Wnt 8b, which is elevated in this period 4. Fox G1 is also genetically associated with infantile spasms 8...the Warburg effect’s role in non- cancerous tissues is largely unexplored. Second, in other diseases such as diabetes , Wnt signaling has emerged as...epilepsy and infantile spasms, we found that both mechanisms appeared to contribute. Two of the three genes came from our observation that several genes

  1. CCR7 signaling pathway and retinal neovascularization

    Directory of Open Access Journals (Sweden)

    Lin-Hui Yuan

    2015-11-01

    Full Text Available Retinal neovascularization diseases are the major causes of blindness. C-C chemokine receptor type 7(CCR7can promote the expression of vascular endothelial growth factor(VEGFthrough the extracellular signal regulated kinase(ERKpathway, leading to vascular leakage, proliferation of vascular endothelial cell, neovascularization and etc. The detection of CCR7 can guide the diagnosis and treatments of retinal neovascularization diseases.

  2. TSLP signaling pathway map: a platform for analysis of TSLP-mediated signaling.

    Science.gov (United States)

    Zhong, Jun; Sharma, Jyoti; Raju, Rajesh; Palapetta, Shyam Mohan; Prasad, T S Keshava; Huang, Tai-Chung; Yoda, Akinori; Tyner, Jeffrey W; van Bodegom, Diederik; Weinstock, David M; Ziegler, Steven F; Pandey, Akhilesh

    2014-01-01

    Thymic stromal lymphopoietin (TSLP) is a four-helix bundle cytokine that plays a critical role in the regulation of immune responses and in the differentiation of hematopoietic cells. TSLP signals through a heterodimeric receptor complex consisting of an interleukin-7 receptor α chain and a unique TSLP receptor (TSLPR) [also known as cytokine receptor-like factor 2 (CRLF2)]. Cellular targets of TSLP include dendritic cells, B cells, mast cells, regulatory T (Treg) cells and CD4+ and CD8+ T cells. The TSLP/TSLPR axis can activate multiple signaling transduction pathways including the JAK/STAT pathway and the PI-3 kinase pathway. Aberrant TSLP/TSLPR signaling has been associated with a variety of human diseases including asthma, atopic dermatitis, nasal polyposis, inflammatory bowel disease, eosinophilic eosophagitis and, most recently, acute lymphoblastic leukemia. A centralized resource of the TSLP signaling pathway cataloging signaling events is not yet available. In this study, we present a literature-annotated resource of reactions in the TSLP signaling pathway. This pathway map is publicly available through NetPath (http://www.netpath.org/), an open access signal transduction pathway resource developed previously by our group. This map includes 236 molecules and 252 reactions that are involved in TSLP/TSLPR signaling pathway. We expect that the TSLP signaling pathway map will provide a rich resource to study the biology of this important cytokine as well as to identify novel therapeutic targets for diseases associated with dysregulated TSLP/TSLPR signaling. Database URL: http://www.netpath.org/pathways?path_id=NetPath_24.

  3. Oscillatory Dynamics of the Extracellular Signal-regulated Kinase Pathway

    Energy Technology Data Exchange (ETDEWEB)

    Shankaran, Harish; Wiley, H. S.

    2010-12-01

    The extracellular signal-regulated kinase (ERK) pathway is a central signaling pathway in development and disease and is regulated by multiple negative and positive feedback loops. Recent studies have shown negative feedback from ERK to upstream regulators can give rise to biochemical oscillations with a periodicity of between 15-30 minutes. Feedback due to the stimulated transcription of negative regulators of the ERK pathway can also give rise to transcriptional oscillations with a periodicity of 1-2h. The biological significance of these oscillations is not clear, but recent evidence suggests that transcriptional oscillations participate in developmental processes, such as somite formation. Biochemical oscillations are more enigmatic, but could provide a mechanism for encoding different types of inputs into a common signaling pathway.

  4. Microenvironment Dependent Photobiomodulation on Function-Specific Signal Transduction Pathways

    Directory of Open Access Journals (Sweden)

    Timon Cheng-Yi Liu

    2014-01-01

    Full Text Available Cellular photobiomodulation on a cellular function has been shown to be homeostatic. Its function-specific pathway mechanism would be further discussed in this paper. The signal transduction pathways maintaining a normal function in its function-specific homeostasis (FSH, resisting the activation of many other irrelative signal transduction pathways, are so sparse that it can be supposed that there may be normal function-specific signal transduction pathways (NSPs. A low level laser irradiation or monochromatic light may promote the activation of partially activated NSP and/or its redundant NSP so that it may induce the second-order phase transition of a function from its dysfunctional one far from its FSH to its normal one in a function-specific microenvironment and may also induce the first-order functional phase transition of the normal function from low level to high level.

  5. 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

  6. ERβ induces the differentiation of cultured osteoblasts by both Wnt/β-catenin signaling pathway and estrogen signaling pathways

    Energy Technology Data Exchange (ETDEWEB)

    Yin, Xinhua [Department of Spine Surgery, Xiangya Hospital of Central South University, Changsha (China); Wang, Xiaoyuan [Department of Nephrology, Xi An Honghui Hospital, Xi an (China); Hu, Xiongke; Chen, Yong; Zeng, Kefeng [Department of Spine Surgery, Xiangya Hospital of Central South University, Changsha (China); Zhang, Hongqi, E-mail: zhq9699@126.com [Department of Spine Surgery, Xiangya Hospital of Central South University, Changsha (China)

    2015-07-01

    Although 17β-estradial (E2) is known to stimulate bone formation, the underlying mechanisms are not fully understood. Recent studies have implicated the Wnt/β-catenin pathway as a major signaling cascade in bone biology. The interactions between Wnt/β-catenin signaling pathway and estrogen signaling pathways have been reported in many tissues. In this study, E2 significantly increased the expression of β-catenin by inducing phosphorylations of GSK3β at serine 9. ERβ siRNAs were transfected into MC3T3-E1 cells and revealed that ERβ involved E2-induced osteoblasts proliferation and differentiation via Wnt/β-catenin signaling. The osteoblast differentiation genes (BGP, ALP and OPN) and proliferation related gene (cyclin D1) expression were significantly induced by E2-mediated ERβ. Furthermore immunofluorescence and immunoprecipitation analysis demonstrated that E2 induced the accumulation of β-catenin protein in the nucleus which leads to interaction with T-cell-specific transcription factor/lymphoid enhancer binding factor (TCF/LEF) transcription factors. Taken together, these findings suggest that E2 promotes osteoblastic proliferation and differentiation by inducing proliferation-related and differentiation-related gene expression via ERβ/GSK-3β-dependent Wnt/β-catenin signaling pathway. Our findings provide novel insights into the mechanisms of action of E2 in osteoblastogenesis. - Highlights: • 17β-estradial (E2) promotes GSK3-β phosphorylation. • E2 activates the Wnt/β-catenin signaling pathway. • The Wnt/β-catenin signaling pathway interacts with estrogen signaling pathways. • E2-mediated ER induced osteoblast differentiation and proliferation related genes expression.

  7. ERβ induces the differentiation of cultured osteoblasts by both Wnt/β-catenin signaling pathway and estrogen signaling pathways

    International Nuclear Information System (INIS)

    Yin, Xinhua; Wang, Xiaoyuan; Hu, Xiongke; Chen, Yong; Zeng, Kefeng; Zhang, Hongqi

    2015-01-01

    Although 17β-estradial (E2) is known to stimulate bone formation, the underlying mechanisms are not fully understood. Recent studies have implicated the Wnt/β-catenin pathway as a major signaling cascade in bone biology. The interactions between Wnt/β-catenin signaling pathway and estrogen signaling pathways have been reported in many tissues. In this study, E2 significantly increased the expression of β-catenin by inducing phosphorylations of GSK3β at serine 9. ERβ siRNAs were transfected into MC3T3-E1 cells and revealed that ERβ involved E2-induced osteoblasts proliferation and differentiation via Wnt/β-catenin signaling. The osteoblast differentiation genes (BGP, ALP and OPN) and proliferation related gene (cyclin D1) expression were significantly induced by E2-mediated ERβ. Furthermore immunofluorescence and immunoprecipitation analysis demonstrated that E2 induced the accumulation of β-catenin protein in the nucleus which leads to interaction with T-cell-specific transcription factor/lymphoid enhancer binding factor (TCF/LEF) transcription factors. Taken together, these findings suggest that E2 promotes osteoblastic proliferation and differentiation by inducing proliferation-related and differentiation-related gene expression via ERβ/GSK-3β-dependent Wnt/β-catenin signaling pathway. Our findings provide novel insights into the mechanisms of action of E2 in osteoblastogenesis. - Highlights: • 17β-estradial (E2) promotes GSK3-β phosphorylation. • E2 activates the Wnt/β-catenin signaling pathway. • The Wnt/β-catenin signaling pathway interacts with estrogen signaling pathways. • E2-mediated ER induced osteoblast differentiation and proliferation related genes expression

  8. Autophagy and the nutritional signaling pathway

    Directory of Open Access Journals (Sweden)

    Long HE,Shabnam ESLAMFAM,Xi MA,Defa LI

    2016-09-01

    Full Text Available During their growth and development, animals adapt to tremendous changes in order to survive. These include responses to both environmental and physiological changes and autophagy is one of most important adaptive and regulatory mechanisms. Autophagy is defined as an autolytic process to clear damaged cellular organelles and recycle the nutrients via lysosomic degradation. The process of autophagy responds to special conditions such as nutrient withdrawal. Once autophagy is induced, phagophores form and then elongate and curve to form autophagosomes. Autophagosomes then engulf cargo, fuse with endosomes, and finally fuse with lysosomes for maturation. During the initiation process, the ATG1/ULK1 (unc-51-like kinase 1 and VPS34 (which encodes a class III phosphatidylinositol (PtdIns 3-kinase complexes are critical in recruitment and assembly of other complexes required for autophagy. The process of autophagy is regulated by autophagy related genes (ATGs. Amino acid and energy starvation mediate autophagy by activating mTORC1 (mammalian target of rapamycin and AMP-activated protein kinase (AMPK. AMPK is the energy status sensor, the core nutrient signaling component and the metabolic kinase of cells. This review mainly focuses on the mechanism of autophagy regulated by nutrient signaling especially for the two important complexes, ULK1 and VPS34.

  9. Vasopressin activates Akt/mTOR pathway in smooth muscle cells cultured in high glucose concentration

    Energy Technology Data Exchange (ETDEWEB)

    Montes, Daniela K.; Brenet, Marianne; Muñoz, Vanessa C.; Burgos, Patricia V.; Villanueva, Carolina I. [Department of Physiology, Universidad Austral de Chile, Valdivia 509-9200 (Chile); Figueroa, Carlos D. [Department of Anatomy, Histology and Pathology, Universidad Austral de Chile, Valdivia 509-9200 (Chile); González, Carlos B., E-mail: cbgonzal@uach.cl [Department of Physiology, Universidad Austral de Chile, Valdivia 509-9200 (Chile); Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, TX 77555 (United States)

    2013-11-29

    Highlights: •AVP induces mTOR phosphorylation in A-10 cells cultured in high glucose concentration. •The mTOR phosphorylation is mediated by the PI3K/Akt pathway activation. •The AVP-induced mTOR phosphorylation inhibited autophagy and stimulated cell proliferation. -- Abstract: Mammalian target of rapamycin (mTOR) complex is a key regulator of autophagy, cell growth and proliferation. Here, we studied the effects of arginine vasopressin (AVP) on mTOR activation in vascular smooth muscle cells cultured in high glucose concentration. AVP induced the mTOR phosphorylation in A-10 cells grown in high glucose, in contrast to cells cultured in normal glucose; wherein, only basal phosphorylation was observed. The AVP-induced mTOR phosphorylation was inhibited by a PI3K inhibitor. Moreover, the AVP-induced mTOR activation inhibited autophagy and increased thymidine incorporation in cells grown in high glucose. This increase was abolished by rapamycin which inhibits the mTORC1 complex formation. Our results suggest that AVP stimulates mTOR phosphorylation by activating the PI3K/Akt signaling pathway and, subsequently, inhibits autophagy and raises cell proliferation in A-10 cells maintained in high glucose concentration.

  10. Sepsis and mechnaical ventilation restrain translation initiation in skeletal muscle by inducing AMPK-associated TSC[2] restriction of mTOR signaling in pigs

    Science.gov (United States)

    In skeletal muscle, AMP-activated protein kinase (AMPK) acts as a cellular energy sensor of AMP: ATP and modulates translation by repressing mammalian target of rapamycin (mTOR) activation. Endotoxin (LPS)-induced sepsis reduces muscle protein synthesis by blunting translation initiation. We hypothe...

  11. Interaction of TGFβ and BMP signaling pathways during chondrogenesis.

    Directory of Open Access Journals (Sweden)

    Bettina Keller

    2011-01-01

    Full Text Available TGFβ and BMP signaling pathways exhibit antagonistic activities during the development of many tissues. Although the crosstalk between BMP and TGFβ signaling pathways is well established in bone development, the relationship between these two pathways is less well defined during cartilage development and postnatal homeostasis. We generated hypomorphic mouse models of cartilage-specific loss of BMP and TGFβ signaling to assess the interaction of these pathways in postnatal growth plate homeostasis. We further used the chondrogenic ATDC5 cell line to test effects of BMP and TGFβ signaling on each other's downstream targets. We found that conditional deletion of Smad1 in chondrocytes resulted in a shortening of the growth plate. The addition of Smad5 haploinsufficiency led to a more severe phenotype with shorter prehypertrophic and hypertrophic zones and decreased chondrocyte proliferation. The opposite growth plate phenotype was observed in a transgenic mouse model of decreased chondrocytic TGFβ signaling that was generated by expressing a dominant negative form of the TGFβ receptor I (ΔTβRI in cartilage. Histological analysis demonstrated elongated growth plates with enhanced Ihh expression, as well as an increased proliferation rate with altered production of extracellular matrix components. In contrast, in chondrogenic ATDC5 cells, TGFβ was able to enhance BMP signaling, while BMP2 significantly reduces levels of TGF signaling. In summary, our data demonstrate that during endochondral ossification, BMP and TGFβ signaling can have antagonistic effects on chondrocyte proliferation and differentiation in vivo. We also found evidence of direct interaction between the two signaling pathways in a cell model of chondrogenesis in vitro.

  12. PI3K-Akt signaling activates mTOR-mediated epileptogenesis in organotypic hippocampal culture model of posttraumatic epilepsy

    OpenAIRE

    Berdichevsky, Yevgeny; Dryer, Alexandra M.; Saponjian, Yero; Mahoney, Mark M.; Pimentel, Corrin A.; Lucini, Corrina A.; Usenovic, Marija; Staley, Kevin J.

    2013-01-01

    mTOR is activated in epilepsy, but the mechanisms of mTOR activation in post-traumatic epileptogenesis are unknown. It is also not clear whether mTOR inhibition has an antiepileptogenic, or merely anti-convulsive effect. The rat hippocampal organotypic culture model of post-traumatic epilepsy was used to study the effects of long term (four weeks) inhibition of signaling pathways that interact with mTOR. Ictal activity was quantified by measurement of lactate production and electrical recordi...

  13. Signaling flux redistribution at toll-like receptor pathway junctions.

    Directory of Open Access Journals (Sweden)

    Kumar Selvarajoo

    Full Text Available Various receptors on cell surface recognize specific extracellular molecules and trigger signal transduction altering gene expression in the nucleus. Gain or loss-of-function mutations of one molecule have shown to affect alternative signaling pathways with a poorly understood mechanism. In Toll-like receptor (TLR 4 signaling, which branches into MyD88- and TRAM-dependent pathways upon lipopolysaccharide (LPS stimulation, we investigated the gain or loss-of-function mutations of MyD88. We predict, using a computational model built on the perturbation-response approach and the law of mass conservation, that removal and addition of MyD88 in TLR4 activation, enhances and impairs, respectively, the alternative TRAM-dependent pathway through signaling flux redistribution (SFR at pathway branches. To verify SFR, we treated MyD88-deficient macrophages with LPS and observed enhancement of TRAM-dependent pathway based on increased IRF3 phosphorylation and induction of Cxcl10 and Ifit2. Furthermore, increasing the amount of MyD88 in cultured cells showed decreased TRAM binding to TLR4. Investigating another TLR4 pathway junction, from TRIF to TRAF6, RIP1 and TBK1, the removal of MyD88-dependent TRAF6 increased expression of TRAM-dependent Cxcl10 and Ifit2. Thus, we demonstrate that SFR is a novel mechanism for enhanced activation of alternative pathways when molecules at pathway junctions are removed. Our data suggest that SFR may enlighten hitherto unexplainable intracellular signaling alterations in genetic diseases where gain or loss-of-function mutations are observed.

  14. Using Proteomics To Elucidate Critical Signaling Pathways

    KAUST Repository

    Ahmed, Heba

    2012-11-01

    Despite important advances in the therapy of acute myeloid leukemia (AML) the majority of patients will die from their disease (Appelbaum, Rowe, Radich, & Dick, 2001). Characterization of the aberrant molecular pathways responsible for this malignancy provides a platform to discover alternative treatments to help alter the fate of patients. AML is characterized by a blockage in the differentiation of myeloid cells resulting in the accumulation of highly proliferating immature hematopoietic cells. Since treatments such as chemotherapy rarely destroy the leukemic cells entirely, differentiation induction therapy has become a very attractive treatment option. Interestingly, previous experiments have shown that ligation of CD44, a cell surface glycoprotein strongly expressed on all AML cells, with anti-CD44 monoclonal antibodies (mAbs) could reverse this block in differentiation of leukemic blasts regardless of the AML subtype. To expand the understanding of the cellular regulation and circuitry involved, we aim to apply quantitative phosphoproteomics to monitor dynamic changes in phosphorylation state in response to anti-CD44 treatment. Protein phosphorylation and dephosphorylation is a highly controlled biochemical process that responds to various intracellular and extracellular stimuli. As phosphorylation is a dynamic process, quantification of these phosphorylation events would be vastly insightful. The main objective of this project is to determine the differentiation-dependent phosphoproteome of AML cells upon treatment of cells with the anti-CD44 mAb.In these experiments, optimization of protein extraction, phosphopeptide enrichment and data processing and analysis has been achieved. The primary results show successful phosphoproteome extraction complemented with efficient phosphopeptide enrichment and informative data processing. Further quantification with stable isotope labeling techniques is anticipated to provide candidates for targeted therapy.

  15. Computational identification of signalling pathways in Plasmodium falciparum.

    Science.gov (United States)

    Oyelade, Jelili; Ewejobi, Itunu; Brors, Benedikt; Eils, Roland; Adebiyi, Ezekiel

    2011-06-01

    Malaria is one of the world's most common and serious diseases causing death of about 3 million people each year. Its most severe occurrence is caused by the protozoan Plasmodium falciparum. Reports have shown that the resistance of the parasite to existing drugs is increasing. Therefore, there is a huge and urgent need to discover and validate new drug or vaccine targets to enable the development of new treatments for malaria. The ability to discover these drug or vaccine targets can only be enhanced from our deep understanding of the detailed biology of the parasite, for example how cells function and how proteins organize into modules such as metabolic, regulatory and signal transduction pathways. It has been noted that the knowledge of signalling transduction pathways in Plasmodium is fundamental to aid the design of new strategies against malaria. This work uses a linear-time algorithm for finding paths in a network under modified biologically motivated constraints. We predicted several important signalling transduction pathways in Plasmodium falciparum. We have predicted a viable signalling pathway characterized in terms of the genes responsible that may be the PfPKB pathway recently elucidated in Plasmodium falciparum. We obtained from the FIKK family, a signal transduction pathway that ends up on a chloroquine resistance marker protein, which indicates that interference with FIKK proteins might reverse Plasmodium falciparum from resistant to sensitive phenotype. We also proposed a hypothesis that showed the FIKK proteins in this pathway as enabling the resistance parasite to have a mechanism for releasing chloroquine (via an efflux process). Furthermore, we also predicted a signalling pathway that may have been responsible for signalling the start of the invasion process of Red Blood Cell (RBC) by the merozoites. It has been noted that the understanding of this pathway will give insight into the parasite virulence and will facilitate rational vaccine design

  16. SPV: a JavaScript Signaling Pathway Visualizer.

    Science.gov (United States)

    Calderone, Alberto; Cesareni, Gianni

    2018-03-24

    The visualization of molecular interactions annotated in web resources is useful to offer to users such information in a clear intuitive layout. These interactions are frequently represented as binary interactions that are laid out in free space where, different entities, cellular compartments and interaction types are hardly distinguishable. SPV (Signaling Pathway Visualizer) is a free open source JavaScript library which offers a series of pre-defined elements, compartments and interaction types meant to facilitate the representation of signaling pathways consisting of causal interactions without neglecting simple protein-protein interaction networks. freely available under Apache version 2 license; Source code: https://github.com/Sinnefa/SPV_Signaling_Pathway_Visualizer_v1.0. Language: JavaScript; Web technology: Scalable Vector Graphics; Libraries: D3.js. sinnefa@gmail.com.

  17. Association of MTOR and AKT Gene Polymorphisms with Susceptibility and Survival of Gastric Cancer.

    Directory of Open Access Journals (Sweden)

    Ying Piao

    Full Text Available The phosphoinositide 3-kinase (PI3K/protein kinase B (PKB, AKT/mammalian target of rapamycin (mTOR signaling pathway plays a critical role in angiogenesis and cell growth, proliferation, metabolism, migration, differentiation, and apoptosis. Genetic diversity in key factors of this pathway may influence protein function and signal transduction, contributing to disease initiation and progression. Studies suggest that MTOR rs1064261 and AKT rs1130233 polymorphisms are associated with risk and/or prognosis of multiple cancer types. However, this relationship with gastric cancer (GC remains unclear. The aim of this study was to investigate the role of MTOR and AKT polymorphisms in the risk and prognosis of GC.The Sequenom MassARRAY platform was used to genotype 1842 individuals for MTOR rs1064261 T→C and AKT rs1130233 G→A polymorphisms. ELISA was used to detect Helicobacter pylori antibodies in serum. Immunohistochemical analysis was used to detect total and phosphorylated MTOR and AKT proteins.The MTOR rs1064261 (TC+CC genotype and the AKT rs1130233 (GA+AA genotype were associated with increased risk of GC in men (P = 0.049, P = 0.030. In H. pylori-negative individuals, the AKT rs1130233 GA and (GA+AA genotypes were related to increased risk of atrophic gastritis (AG; P = 0.012, P = 0.024. Notably, the AKT rs1130233 (GA+AA genotype demonstrated significant interactions with H. pylori in disease progression from healthy controls (CON to AG (P = 0.013 and from AG to GC (P = 0.049. Additionally, for individuals with the AKT rs1130233 variant, those in the H. pylori-positive group had higher levels of phosphorylated AKT (p-AKT expression. The AKT rs1130233 genotype was found to be associated with clinicopathological parameters including lymph node metastasis and alcohol drinking (P<0.05.MTOR rs1064261and AKT rs1130233 polymorphisms were associated with increased GC risk in males and increased AG risk in H. pylori-negative individuals. A significant

  18. POSTRANSLATIONAL MODIFICATIONS OF P53: UPSTREAM SIGNALING PATHWAYS.

    Energy Technology Data Exchange (ETDEWEB)

    ANDERSON,C.W.APPELLA,E.

    2003-10-23

    The p53 tumor suppressor is a tetrameric transcription factor that is posttranslational modified at >20 different sites by phosphorylation, acetylation, or sumoylation in response to various cellular stress conditions. Specific posttranslational modifications, or groups of modifications, that result from the activation of different stress-induced signaling pathways are thought to modulate p53 activity to regulate cell fate by inducing cell cycle arrest, apoptosis, or cellular senescence. Here we review recent progress in characterizing the upstream signaling pathways whose activation in response to various genotoxic and non-genotoxic stresses result in p53 posttranslational modifications.

  19. Jatropha curcas Protein Concentrate Stimulates Insulin Signaling, Lipogenesis, Protein Synthesis and the PKCα Pathway in Rat Liver.

    Science.gov (United States)

    León-López, Liliana; Márquez-Mota, Claudia C; Velázquez-Villegas, Laura A; Gálvez-Mariscal, Amanda; Arrieta-Báez, Daniel; Dávila-Ortiz, Gloria; Tovar, Armando R; Torres, Nimbe

    2015-09-01

    Jatropha curcas is an oil seed plant that belongs to the Euphorbiaceae family. Nontoxic genotypes have been reported in Mexico. The purpose of the present work was to evaluate the effect of a Mexican variety of J. curcas protein concentrate (JCP) on weight gain, biochemical parameters, and the expression of genes and proteins involved in insulin signaling, lipogenesis, cholesterol and protein synthesis in rats. The results demonstrated that short-term consumption of JCP increased serum glucose, insulin, triglycerides and cholesterol levels as well as the expression of transcription factors involved in lipogenesis and cholesterol synthesis (SREBP-1 and LXRα). Moreover, there was an increase in insulin signaling mediated by Akt phosphorylation and mTOR. JCP also increased PKCα protein abundance and the activation of downstream signaling pathway targets such as the AP1 and NF-κB transcription factors typically activated by phorbol esters. These results suggested that phorbol esters are present in JCP, and that they could be involved in the activation of PKC which may be responsible for the high insulin secretion and consequently the activation of insulin-dependent pathways. Our data suggest that this Mexican Jatropha variety contains toxic compounds that produce negative metabolic effects which require caution when using in the applications of Jatropha-based products in medicine and nutrition.

  20. Effects of cortisol and dexamethasone on insulin signalling pathways in skeletal muscle of the ovine fetus during late gestation.

    Directory of Open Access Journals (Sweden)

    Juanita K Jellyman

    Full Text Available Before birth, glucocorticoids retard growth, although the extent to which this is mediated by changes in insulin signalling pathways in the skeletal muscle of the fetus is unknown. The current study determined the effects of endogenous and synthetic glucocorticoid exposure on insulin signalling proteins in skeletal muscle of fetal sheep during late gestation. Experimental manipulation of fetal plasma glucocorticoid concentration was achieved by fetal cortisol infusion and maternal dexamethasone treatment. Cortisol infusion significantly increased muscle protein levels of Akt2 and phosphorylated Akt at Ser473, and decreased protein levels of phosphorylated forms of mTOR at Ser2448 and S6K at Thr389. Muscle GLUT4 protein expression was significantly higher in fetuses whose mothers were treated with dexamethasone compared to those treated with saline. There were no significant effects of glucocorticoid exposure on muscle protein abundance of IR-β, IGF-1R, PKCζ, Akt1, calpastatin or muscle glycogen content. The present study demonstrated that components of the insulin signalling pathway in skeletal muscle of the ovine fetus are influenced differentially by naturally occurring and synthetic glucocorticoids. These findings may provide a mechanism by which elevated concentrations of endogenous glucocorticoids retard fetal growth.

  1. Clinical Implications of Hedgehog Pathway Signaling in Prostate Cancer

    Directory of Open Access Journals (Sweden)

    Daniel L. Suzman

    2015-09-01

    Full Text Available Activity in the Hedgehog pathway, which regulates GLI-mediated transcription, is important in organogenesis and stem cell regulation in self-renewing organs, but is pathologically elevated in many human malignancies. Mutations leading to constitutive activation of the pathway have been implicated in medulloblastoma and basal cell carcinoma, and inhibition of the pathway has demonstrated clinical responses leading to the approval of the Smoothened inhibitor, vismodegib, for the treatment of advanced basal cell carcinoma. Aberrant Hedgehog pathway signaling has also been noted in prostate cancer with evidence suggesting that it may render prostate epithelial cells tumorigenic, drive the epithelial-to-mesenchymal transition, and contribute towards the development of castration-resistance through autocrine and paracrine signaling within the tumor microenvironment and cross-talk with the androgen pathway. In addition, there are emerging clinical data suggesting that inhibition of the Hedgehog pathway may be effective in the treatment of recurrent and metastatic prostate cancer. Here we will review these data and highlight areas of active clinical research as they relate to Hedgehog pathway inhibition in prostate cancer.

  2. Auraptene, a Major Compound of Supercritical Fluid Extract of Phalsak (Citrus Hassaku Hort ex Tanaka, Induces Apoptosis through the Suppression of mTOR Pathways in Human Gastric Cancer SNU-1 Cells

    Directory of Open Access Journals (Sweden)

    Jeong Yong Moon

    2015-01-01

    Full Text Available The supercritical extraction method is a widely used process to obtain volatile and nonvolatile compounds by avoiding thermal degradation and solvent residue in the extracts. In search of phytochemicals with potential therapeutic application in gastric cancer, the supercritical fluid extract (SFE of phalsak (Citrus hassaku Hort ex Tanaka fruits was analyzed by gas chromatography-mass spectrometry (GC-MS. Compositional analysis in comparison with the antiproliferative activities of peel and flesh suggested auraptene as the most prominent anticancer compound against gastric cancer cells. SNU-1 cells were the most susceptible to auraptene-induced toxicity among the tested gastric cancer cell lines. Auraptene induced the death of SNU-1 cells through apoptosis, as evidenced by the increased cell population in the sub-G1 phase, the appearance of fragmented nuclei, the proteolytic cleavage of caspase-3 and poly(ADP-ribose polymerase (PARP protein, and depolarization of the mitochondrial membrane. Interestingly, auraptene induces an increase in the phosphorylation of Akt, which is reminiscent of the effect of rapamycin, the mTOR inhibitor that triggers a negative feedback loop on Akt/mTOR pathway. Taken together, these findings provide valuable insights into the anticancer effects of the SFE of the phalsak peel by revealing that auraptene, the major compound of it, induced apoptosis in accompanied with the inhibition of mTOR in SNU-1 cells.

  3. Phylogenetic diversity of stress signalling pathways in fungi

    Directory of Open Access Journals (Sweden)

    Stansfield Ian

    2009-02-01

    Full Text Available Abstract Background Microbes must sense environmental stresses, transduce these signals and mount protective responses to survive in hostile environments. In this study we have tested the hypothesis that fungal stress signalling pathways have evolved rapidly in a niche-specific fashion that is independent of phylogeny. To test this hypothesis we have compared the conservation of stress signalling molecules in diverse fungal species with their stress resistance. These fungi, which include ascomycetes, basidiomycetes and microsporidia, occupy highly divergent niches from saline environments to plant or mammalian hosts. Results The fungi displayed significant variation in their resistance to osmotic (NaCl and sorbitol, oxidative (H2O2 and menadione and cell wall stresses (Calcofluor White and Congo Red. There was no strict correlation between fungal phylogeny and stress resistance. Rather, the human pathogens tended to be more resistant to all three types of stress, an exception being the sensitivity of Candida albicans to the cell wall stress, Calcofluor White. In contrast, the plant pathogens were relatively sensitive to oxidative stress. The degree of conservation of osmotic, oxidative and cell wall stress signalling pathways amongst the eighteen fungal species was examined. Putative orthologues of functionally defined signalling components in Saccharomyces cerevisiae were identified by performing reciprocal BLASTP searches, and the percent amino acid identities of these orthologues recorded. This revealed that in general, central components of the osmotic, oxidative and cell wall stress signalling pathways are relatively well conserved, whereas the sensors lying upstream and transcriptional regulators lying downstream of these modules have diverged significantly. There was no obvious correlation between the degree of conservation of stress signalling pathways and the resistance of a particular fungus to the corresponding stress. Conclusion Our

  4. Reversal of muscle atrophy by Zhimu-Huangbai herb-pair via Akt/mTOR/FoxO3 signal pathway in streptozotocin-induced diabetic mice.

    Directory of Open Access Journals (Sweden)

    Jinbao Zhang

    Full Text Available Skeletal muscle atrophy is one of the serious complications of diabetes. Zhimu-Huangbai herb-pair (ZB is widely used in Chinese traditional medicine formulas for treating Xiaoke (known as diabetes and its complications. However, the effect of ZB on reversal of muscle atrophy and the underlying mechanisms remain unknown. In this research, we investigated the effect and possible mechanisms of ZB on skeletal muscle atrophy in diabetic mice. Animal model of diabetic muscle atrophy was developed by high fat diet (HFD feeding plus streptozotocin (STZ injection. After oral adminstration of ZB for 6 weeks, the effects of ZB on reversal of muscle atrophy and the underlying mechanisms were evaluated by biochemical, histological and western blot methods. The skeletal muscle weight, strength, and cross-sectional area of diabetic mice were significantly increased by ZB treatment. Biochemical results showed that ZB treatment reduced the serum glucose level, and elevated the serum insulin-like growth factor 1 (IGF-1 and insulin levels significantly compared with untreated diabetic group. The western blot results showed that ZB activated the mTOR signal pathway, shown as increased phosphorylations (p- of Akt, mTOR, Raptor, S6K1 and reduced Foxo3 expression compared with the model group. ZB could reverse muscle atrophy in diabetic mice. This may be through activation of mTOR signaling pathway that promotes protein synthesis, and inactivation foxo3 protein that inhibits protein degradation. These findings suggested that ZB may be considered as a potential candidate drug in treatment of diabetic muscle atrophy.

  5. Wnt pathway in Dupuytren disease: connecting profibrotic signals.

    Science.gov (United States)

    van Beuge, Marike M; Ten Dam, Evert-Jan P M; Werker, Paul M N; Bank, Ruud A

    2015-12-01

    A role of Wnt signaling in Dupuytren disease, a fibroproliferative disease of the hand and fingers, has not been fully elucidated. We examined a large set of Wnt pathway components and signaling targets and found significant dysregulation of 41 Wnt-related genes in tissue from the Dupuytren nodules compared with patient-matched control tissue. A large proportion of genes coding for Wnt proteins themselves was downregulated. However, both canonical Wnt targets and components of the noncanonical signaling pathway were upregulated. Immunohistochemical analysis revealed that protein expression of Wnt1-inducible secreted protein 1 (WISP1), a known Wnt target, was increased in nodules compared with control tissue, but knockdown of WISP1 using small interfering RNA (siRNA) in the Dupuytren myofibroblasts did not confirm a functional role. The protein expression of noncanonical pathway components Wnt5A and VANGL2 as well as noncanonical coreceptors Ror2 and Ryk was increased in nodules. On the contrary, the strongest downregulated genes in this study were 4 antagonists of Wnt signaling (DKK1, FRZB, SFRP1, and WIF1). Downregulation of these genes in the Dupuytren tissue was mimicked in vitro by treating normal fibroblasts with transforming growth factor β1 (TGF-β1), suggesting cross talk between different profibrotic pathways. Furthermore, siRNA-mediated knockdown of these antagonists in normal fibroblasts led to increased nuclear translocation of Wnt target β-catenin in response to TGF-β1 treatment. In conclusion, we have shown extensive dysregulation of Wnt signaling in affected tissue from Dupuytren disease patients. Components of both the canonical and the noncanonical pathways are upregulated, whereas endogenous antagonists are downregulated, possibly via interaction with other profibrotic pathways. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. mTOR inhibitors alone and in combination with JAK2 inhibitors effectively inhibit cells of myeloproliferative neoplasms.

    Directory of Open Access Journals (Sweden)

    Costanza Bogani

    Full Text Available BACKGROUND: Dysregulated signaling of the JAK/STAT pathway is a common feature of chronic myeloproliferative neoplasms (MPN, usually associated with JAK2V617F mutation. Recent clinical trials with JAK2 inhibitors showed significant improvements in splenomegaly and constitutional symptoms in patients with myelofibrosis but meaningful molecular responses were not documented. Accordingly, there remains a need for exploring new treatment strategies of MPN. A potential additional target for treatment is represented by the PI3K/AKT/mammalian target of rapamycin (mTOR pathway that has been found constitutively activated in MPN cells; proof-of-evidence of efficacy of the mTOR inhibitor RAD001 has been obtained recently in a Phase I/II trial in patients with myelofibrosis. The aim of the study was to characterize the effects in vitro of mTOR inhibitors, used alone and in combination with JAK2 inhibitors, against MPN cells. FINDINGS: Mouse and human JAK2V617F mutated cell lines and primary hematopoietic progenitors from MPN patients were challenged with an allosteric (RAD001 and an ATP-competitive (PP242 mTOR inhibitor and two JAK2 inhibitors (AZD1480 and ruxolitinib. mTOR inhibitors effectively reduced proliferation and colony formation of cell lines through a slowed cell division mediated by changes in cell cycle transition to the S-phase. mTOR inhibitors also impaired the proliferation and prevented colony formation from MPN hematopoietic progenitors at doses significantly lower than healthy controls. JAK2 inhibitors produced similar antiproliferative effects in MPN cell lines and primary cells but were more potent inducers of apoptosis, as also supported by differential effects on cyclinD1, PIM1 and BcLxL expression levels. Co-treatment of mTOR inhibitor with JAK2 inhibitor resulted in synergistic activity against the proliferation of JAK2V617F mutated cell lines and significantly reduced erythropoietin-independent colony growth in patients with

  7. YAP regulates neuronal differentiation through Sonic hedgehog signaling pathway

    International Nuclear Information System (INIS)

    Lin, Yi-Ting; Ding, Jing-Ya; Li, Ming-Yang; Yeh, Tien-Shun; Wang, Tsu-Wei; Yu, Jenn-Yah

    2012-01-01

    Tight regulation of cell numbers by controlling cell proliferation and apoptosis is important during development. Recently, the Hippo pathway has been shown to regulate tissue growth and organ size in Drosophila. In mammalian cells, it also affects cell proliferation and differentiation in various tissues, including the nervous system. Interplay of several signaling cascades, such as Notch, Wnt, and Sonic Hedgehog (Shh) pathways, control cell proliferation during neuronal differentiation. However, it remains unclear whether the Hippo pathway coordinates with other signaling cascades in regulating neuronal differentiation. Here, we used P19 cells, a mouse embryonic carcinoma cell line, as a model to study roles of YAP, a core component of the Hippo pathway, in neuronal differentiation. P19 cells can be induced to differentiate into neurons by expressing a neural bHLH transcription factor gene Ascl1. Our results showed that YAP promoted cell proliferation and inhibited neuronal differentiation. Expression of Yap activated Shh but not Wnt or Notch signaling activity during neuronal differentiation. Furthermore, expression of Yap increased the expression of Patched homolog 1 (Ptch1), a downstream target of the Shh signaling. Knockdown of Gli2, a transcription factor of the Shh pathway, promoted neuronal differentiation even when Yap was over-expressed. We further demonstrated that over-expression of Yap inhibited neuronal differentiation in primary mouse cortical progenitors and Gli2 knockdown rescued the differentiation defect in Yap over-expressing cells. In conclusion, our study reveals that Shh signaling acts downstream of YAP in regulating neuronal differentiation. -- Highlights: ► YAP promotes cell proliferation and inhibits neuronal differentiation in P19 cells. ► YAP promotes Sonic hedgehog signaling activity during neuronal differentiation. ► Knockdown of Gli2 rescues the Yap-overexpression phenotype in P19 cells. ► Knockdown of Gli2 rescues the Yap

  8. YAP regulates neuronal differentiation through Sonic hedgehog signaling pathway

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Yi-Ting; Ding, Jing-Ya [Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei 112, Taiwan (China); Li, Ming-Yang [Department of Life Science, National Taiwan Normal University, Taipei 116, Taiwan (China); Yeh, Tien-Shun [Department of Anatomy and Cell Biology, National Yang-Ming University, Taipei 112, Taiwan (China); Wang, Tsu-Wei [Department of Life Science, National Taiwan Normal University, Taipei 116, Taiwan (China); Yu, Jenn-Yah [Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei 112, Taiwan (China); Brain Research Center, National Yang-Ming University, Taipei 112, Taiwan (China)

    2012-09-10

    Tight regulation of cell numbers by controlling cell proliferation and apoptosis is important during development. Recently, the Hippo pathway has been shown to regulate tissue growth and organ size in Drosophila. In mammalian cells, it also affects cell proliferation and differentiation in various tissues, including the nervous system. Interplay of several signaling cascades, such as Notch, Wnt, and Sonic Hedgehog (Shh) pathways, control cell proliferation during neuronal differentiation. However, it remains unclear whether the Hippo pathway coordinates with other signaling cascades in regulating neuronal differentiation. Here, we used P19 cells, a mouse embryonic carcinoma cell line, as a model to study roles of YAP, a core component of the Hippo pathway, in neuronal differentiation. P19 cells can be induced to differentiate into neurons by expressing a neural bHLH transcription factor gene Ascl1. Our results showed that YAP promoted cell proliferation and inhibited neuronal differentiation. Expression of Yap activated Shh but not Wnt or Notch signaling activity during neuronal differentiation. Furthermore, expression of Yap increased the expression of Patched homolog 1 (Ptch1), a downstream target of the Shh signaling. Knockdown of Gli2, a transcription factor of the Shh pathway, promoted neuronal differentiation even when Yap was over-expressed. We further demonstrated that over-expression of Yap inhibited neuronal differentiation in primary mouse cortical progenitors and Gli2 knockdown rescued the differentiation defect in Yap over-expressing cells. In conclusion, our study reveals that Shh signaling acts downstream of YAP in regulating neuronal differentiation. -- Highlights: Black-Right-Pointing-Pointer YAP promotes cell proliferation and inhibits neuronal differentiation in P19 cells. Black-Right-Pointing-Pointer YAP promotes Sonic hedgehog signaling activity during neuronal differentiation. Black-Right-Pointing-Pointer Knockdown of Gli2 rescues the Yap

  9. Effects of CD44 Ligation on Signaling and Metabolic Pathways in Acute Myeloid Leukemia

    KAUST Repository

    Madhoun, Nour Y.

    2017-04-01

    Acute myeloid leukemia (AML) is characterized by a blockage in the differentiation of myeloid cells at different stages. CD44-ligation using anti-CD44 monoclonal antibodies (mAbs) has been shown to reverse the blockage of differentiation and to inhibit the proliferation of blasts in most AML-subtypes. However, the molecular mechanisms underlying this property have not been fully elucidated. Here, we sought to I) analyze the effects of anti-CD44 mAbs on downstream signaling pathways, including the ERK1/2 (extracellular signal-regulated kinase 1 and 2) and mTOR (mammalian target of rapamycin) pathways and II) use state-of-the-art Nuclear Magnetic Resonance (NMR) technology to determine the global metabolic changes during differentiation induction of AML cells using anti-CD44 mAbs and other two previously reported differentiation agents. In the first objective (Chapter 4), our studies provide evidence that CD44-ligation with specific mAbs in AML cells induced an increase in ERK1/2 phosphorylation. The use of the MEK inhibitor (U0126) significantly inhibited the CD44-induced differentiation of HL60 cells, suggesting that ERK1/2 is critical for the CD44-triggered differentiation in AML. In addition, this was accompanied by a marked decrease in the phosphorylation of the mTORC1 and mTORC2 complexes, which are strongly correlated with the inhibition of the PI3K/Akt pathway. In the second objective (Chapter 5), 1H NMR experiments demonstrated that considerable changes in the metabolic profiles of HL60 cells were induced in response to each differentiation agent. These most notable metabolites that significantly changed upon CD44 ligation were involved in the tricarboxylic acid (TCA) cycle and glycolysis such as, succinate, fumarate and lactate. Therefore, we sought to analyze the mechanisms underlying their alterations. Our results revealed that anti-CD44 mAbs treatment induced upregulation in fumarate hydratase (FH) expression and its activity which was accompanied by a

  10. DMPD: Multiple signaling pathways leading to the activation of interferon regulatoryfactor 3. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 12213596 Multiple signaling pathways leading to the activation of interferon regula...(.html) (.csml) Show Multiple signaling pathways leading to the activation of interferon regulatoryfactor 3.... PubmedID 12213596 Title Multiple signaling pathways leading to the activation of

  11. Signaling Pathways in Leiomyoma: Understanding Pathobiology and Implications for Therapy

    Science.gov (United States)

    Borahay, Mostafa A; Al-Hendy, Ayman; Kilic, Gokhan S; Boehning, Darren

    2015-01-01

    Uterine leiomyomas are the most common tumors of the female genital tract, affecting 50% to 70% of females by the age of 50. Despite their prevalence and enormous medical and economic impact, no effective medical treatment is currently available. This is, in part, due to the poor understanding of their underlying pathobiology. Although they are thought to start as a clonal proliferation of a single myometrial smooth muscle cell, these early cytogenetic alterations are considered insufficient for tumor development and additional complex signaling pathway alterations are crucial. These include steroids, growth factors, transforming growth factor-beta (TGF-β)/Smad; wingless-type (Wnt)/β-catenin, retinoic acid, vitamin D, and peroxisome proliferator-activated receptor γ (PPARγ). An important finding is that several of these pathways converge in a summative way. For example, mitogen-activated protein kinase (MAPK) and Akt pathways seem to act as signal integrators, incorporating input from several signaling pathways, including growth factors, estrogen and vitamin D. This underlines the multifactorial origin and complex nature of these tumors. In this review, we aim to dissect these pathways and discuss their interconnections, aberrations and role in leiomyoma pathobiology. We also aim to identify potential targets for development of novel therapeutics. PMID:25879625

  12. Network features and pathway analyses of a signal transduction cascade

    Directory of Open Access Journals (Sweden)

    Ryoji Yanashima

    2009-05-01

    Full Text Available The scale-free and small-world network models reflect the functional units of networks. However, when we investigated the network properties of a signaling pathway using these models, no significant differences were found between the original undirected graphs and the graphs in which inactive proteins were eliminated from the gene expression data. We analyzed signaling networks by focusing on those pathways that best reflected cellular function. Therefore, our analysis of pathways started from the ligands and progressed to transcription factors and cytoskeletal proteins. We employed the Python module to assess the target network. This involved comparing the original and restricted signaling cascades as a directed graph using microarray gene expression profiles of late onset Alzheimer's disease. The most commonly used method of shortest-path analysis neglects to consider the influences of alternative pathways that can affect the activation of transcription factors or cytoskeletal proteins. We therefore introduced included k-shortest paths and k-cycles in our network analysis using the Python modules, which allowed us to attain a reasonable computational time and identify k-shortest paths. This technique reflected results found in vivo and identified pathways not found when shortest path or degree analysis was applied. Our module enabled us to comprehensively analyse the characteristics of biomolecular networks and also enabled analysis of the effects of diseases considering the feedback loop and feedforward loop control structures as an alternative path.

  13. Interaction Dynamics Determine Signaling and Output Pathway Responses

    Directory of Open Access Journals (Sweden)

    Klement Stojanovski

    2017-04-01

    Full Text Available The understanding of interaction dynamics in signaling pathways can shed light on pathway architecture and provide insights into targets for intervention. Here, we explored the relevance of kinetic rate constants of a key upstream osmosensor in the yeast high-osmolarity glycerol-mitogen-activated protein kinase (HOG-MAPK pathway to signaling output responses. We created mutant pairs of the Sln1-Ypd1 complex interface that caused major compensating changes in the association (kon and dissociation (koff rate constants (kinetic perturbations but only moderate changes in the overall complex affinity (Kd. Yeast cells carrying a Sln1-Ypd1 mutant pair with moderate increases in kon and koff displayed a lower threshold of HOG pathway activation than wild-type cells. Mutants with higher kon and koff rates gave rise to higher basal signaling and gene expression but impaired osmoadaptation. Thus, the kon and koff rates of the components in the Sln1 osmosensor determine proper signaling dynamics and osmoadaptation.

  14. DMPD: TLR signaling. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available kira S. Publication Cell Death Differ. 2006 May;13(5):816-25. Pathway - PNG File (.png) SVG File (.svg) HTML File (.html...16410796 TLR signaling. Kawai T, Akira S. Cell Death Differ. 2006 May;13(5):816-25. (.png) (.svg) (.html

  15. Regulation of insect behavior via the insulin-signaling pathway

    Directory of Open Access Journals (Sweden)

    Renske eErion

    2013-12-01

    Full Text Available The insulin/insulin-like growth factor signaling (IIS pathway is well established as a critical regulator of growth and metabolic homeostasis across the animal kingdom. Insulin-like peptides (ILPs, the functional analogs of mammalian insulin, were initially discovered in the silkmoth Bombyx mori and subsequently identified in many other insect species. Initial research focused on the role of insulin signaling in metabolism, cell proliferation, development, reproduction and aging. More recently however, increasing attention has been given to the role of insulin in the regulation of neuronal function and behavior. Here we review the role of insulin signaling in two specific insect behaviors: feeding and locomotion.

  16. Critical analysis of the potential for therapeutic targeting of mammalian target of rapamycin (mTOR in gastric cancer

    Directory of Open Access Journals (Sweden)

    Inokuchi M

    2014-04-01

    Full Text Available Mikito Inokuchi,1 Keiji Kato,1 Kazuyuki Kojima,2 Kenichi Sugihara1 1Department of Surgical Oncology, 2Department of Minimally Invasive Surgery, Tokyo Medical and Dental University, Tokyo, Japan Abstract: Multidisciplinary treatment including chemotherapy has become the global standard of care for patients with metastatic gastric cancer (mGC; nonetheless, survival remains poor. Although many molecular-targeted therapies have been developed for various cancers, only anti-HER2 treatment has produced promising results in patients with mGC. Mammalian target of rapamycin (mTOR plays a key role in cell proliferation, antiapoptosis, and metastasis in signaling pathways from the tyrosine kinase receptor, and its activation has been demonstrated in gastric cancer (GC cells. This review discusses the clinical relevance of mTOR in GC and examines its potential as a therapeutic target in patients with mGC. Preclinical studies in animal models suggest that suppression of the mTOR pathway inhibits the proliferation of GC cells and delays tumor progression. The mTOR inhibitor everolimus has been evaluated as second- or third-line treatment in clinical trials. Adverse events were well tolerated although the effectiveness of everolimus alone was limited. Everolimus is now being evaluated in combination with chemotherapy in Phase III clinical studies in this subgroup of patients. Two Phase III studies include exploratory biomarker research designed to evaluate the predictive value of the expression or mutation of molecules related to the Akt/mTOR signaling pathway. These biomarker studies may lead to the realization of targeted therapy for selected patients with mGC in the future. Keywords: gastric cancer, mTOR, everolimus

  17. Role of Notch signalling pathway in cancer and its association with ...

    Indian Academy of Sciences (India)

    The Notch signalling pathway is an evolutionarily conserved cell signalling pathway involved in the development of organ- ... Abnormal Notch signalling is seen in many cancers like T-cell acute ...... Morgan T. H. 1917 The theory of the gene.

  18. Atorvastatin enhances neurite outgrowth in cortical neurons in vitro via up-regulating the Akt/mTOR and Akt/GSK-3β signaling pathways

    Science.gov (United States)

    Jin, Ying; Sui, Hai-juan; Dong, Yan; Ding, Qi; Qu, Wen-hui; Yu, Sheng-xue; Jin, Ying-xin

    2012-01-01

    Aim: To investigate whether atorvastatin can promote formation of neurites in cultured cortical neurons and the signaling mechanisms responsible for this effect. Methods: Cultured rat cerebral cortical neurons were incubated with atorvastatin (0.05–10 μmol/L) for various lengths of time. For pharmacological experiments, inhibitors were added 30 min prior to addition of atorvastatin. Control cultures received a similar amount of DMSO. Following the treatment period, phase-contrast digital images were taken. Digital images of neurons were analyzed for total neurite branch length (TNBL), neurite number, terminal branch number, and soma area by SPOT Advanced Imaging software. After incubation with atorvastatin for 48 h, the levels of phosphorylated 3-phosphoinoside-dependent protein kinase-1 (PDK1), phospho-Akt, phosphorylated mammalian target of rapamycin (mTOR), phosphorylated 4E-binding protein 1 (4E-BP1), p70S6 kinase (p70S6K), and glycogen synthase kinase-3β (GSK-3β) in the cortical neurons were evaluated using Western blotting analyses. Results: Atorvastatin (0.05–10 μmol/L) resulted in dose-dependent increase in neurite number and length in these neurons. Pretreatment of the cortical neurons with phosphatidylinositol 3-kinase (PI3K) inhibitors LY294002 (30 μmol/L) and wortmannin (5 μmol/L), Akt inhibitor tricribine (1 μmol/L) or mTOR inhibitor rapamycin (100 nmol/L) blocked the atorvastatin-induced increase in neurite outgrowth, suggesting that atorvastatin promoted neurite outgrowth via activating the PI3K/Akt/mTOR signaling pathway. Atorvastatin (10 μmol/L) significantly increased the levels of phosphorylated PDK1, Akt and mTOR in the cortical neurons, which were prevented by LY294002 (30 μmol/L). Moreover, atorvastatin (10 μmol/L) stimulated the phosphorylation of 4E-BP1 and p70S6K, the substrates of mTOR, in the cortical neurons. In addition, atorvastatin (10 μmol/L) significantly increased the phosphorylated GSK-3β level in the cortical

  19. Fisetin inhibits laryngeal carcinoma through regulation of AKT/NF-κB/mTOR and ERK1/2 signaling pathways.

    Science.gov (United States)

    Zhang, Xi-Jun; Jia, Shen-Shan

    2016-10-01

    Targeting cancer cells is crucial for improving the efficiency of laryngeal cancer treatment. However, the signaling pathway and therapeutic strategy, related to the tumor, still need further research. Dietary flavonoid fisetin (3,3',4',7-tetrahydroxyflavone) found in many fruits and vegetables has been shown in preclinical studies to inhibit cancer growth through regulating cell cycle, apoptosis, angiogenesis, invasion and metastasis without causing any toxicity to normal cells. PI3K/AKT and ERK1/2 have been known as essential signaling pathways to modulate cell proliferation, apoptosis as well as autophagy via mTOR, Caspase-3 and NF-κB signals. In our study, flow cytometry and western blot assays suggested that apoptosis was induced by fisetin administration, promoting Caspase-3 expressions by regulating PI3K/AKT/NF-κB. Additionally, fisetin suppressed TU212 cells proliferation, which was linked with ERK1/2 inactivation. Further, the activation of PI3K/AKT-regulated mTOR was inhibited by fisetin, leading to transcription suppression and proliferation inhibition of TU212 cells. In vivo studies also showed that the tumor volume and weight of nude mice were reduced for fisetin use with KI-67 decrease and LC3II increase in tumor tissue samples. Together, our data indicated that fisetin had a potential role in controlling human laryngeal cancer through inhibiting tumor cell proliferation, inducing apoptosis and autophagy regulated by ERK1/2 and AKT/NF-κB/mTOR signaling pathways, which might provide a therapeutic strategy for laryngeal cancer inhibition in future. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  20. Nanoparticle core stability and surface functionalization drive the mTOR signaling pathway in hepatocellular cell lines.

    Czech Academy of Sciences Publication Activity Database

    Lunova, M.; Prokhorov, A.; Jirsa, M.; Hof, M.; Olžyńska, A.; Jurkiewicz, P.; Kubinová, Šárka; Lunov, O.; Dejneka, A.

    2017-01-01

    Roč. 7, č. 1 (2017), s. 16049 ISSN 2045-2322 R&D Projects: GA MŠk(CZ) LO1309 Institutional support: RVO:68378041 Keywords : mesoporous silica nanoparticles * iron-oxide nanoparticles * double-stranded-rna * drug-delivery Subject RIV: FP - Other Medical Disciplines OBOR OECD: Biophysics Impact factor: 4.259, year: 2016

  1. NK cell activation: distinct stimulatory pathways counterbalancing inhibitory signals.

    Science.gov (United States)

    Bakker, A B; Wu, J; Phillips, J H; Lanier, L L

    2000-01-01

    A delicate balance between positive and negative signals regulates NK cell effector function. Activation of NK cells may be initiated by the triggering of multiple adhesion or costimulatory molecules, and can be counterbalanced by inhibitory signals induced by receptors for MHC class I. A common pathway of inhibitory signaling is provided by immunoreceptor tyrosine-based inhibitory motifs (ITIMs) in the cytoplasmic domains of these receptors which mediate the recruitment of SH2 domain-bearing tyrosine phosphate-1 (SHP-1). In contrast to the extensive progress that has been made regarding the negative regulation of NK cell function, our knowledge of the signals that activate NK cells is still poor. Recent studies of the activating receptor complexes have shed new light on the induction of NK cell effector function. Several NK receptors using novel adaptors with immunoreceptor tyrosine-based activation motifs (ITAMs) and with PI 3-kinase recruiting motifs have been implicated in NK cell stimulation.

  2. Signal transduction pathways involved in mechanotransduction in bone cells

    International Nuclear Information System (INIS)

    Liedert, Astrid; Kaspar, Daniela; Blakytny, Robert; Claes, Lutz; Ignatius, Anita

    2006-01-01

    Several in vivo and in vitro studies with different loading regimens showed that mechanical stimuli have an influence on proliferation and differentiation of bone cells. Prerequisite for this influence is the transduction of mechanical signals into the cell, a phenomenon that is termed mechanotransduction, which is essential for the maintenance of skeletal homeostasis in adults. Mechanoreceptors, such as the integrins, cadherins, and stretch-activated Ca 2+ channels, together with various signal transduction pathways, are involved in the mechanotransduction process that ultimately regulates gene expression in the nucleus. Mechanotransduction itself is considered to be regulated by hormones, the extracellular matrix of the osteoblastic cells and the mode of the mechanical stimulus

  3. Signaling transduction pathways involved in basophil adhesion and histamine release

    DEFF Research Database (Denmark)

    Sha, Quan; Poulsen, Lars K.; Gerwien, Jens

    2006-01-01

    Little is known about basophil with respect to the different signaling transduction pathways involved in spontaneous, cytokine or anti-IgE induced adhesion and how this compares to IgE-dependent and IgE-independent mediator secretion. The purpose of the present study was to investigate the roles...... of beta1 and beta2 integrins in basophil adhesion as well as hosphatidylinositol 3-kinase (PI3K), src-kinases and extracellular signal regulated kinase (ERK) 1/2 in basophil adhesion and histamine release (HR)....

  4. Globular Adiponectin Attenuated H2O2-Induced Apoptosis in Rat Chondrocytes by Inducing Autophagy Through the AMPK/ mTOR Pathway.

    Science.gov (United States)

    Hu, Junzheng; Cui, Weiding; Ding, Wenxiao; Gu, Yanqing; Wang, Zhen; Fan, Weimin

    2017-01-01

    APN protected chondrocytes from H2O2-induced apoptosis by inducing autophagy possibly associated with AMPK/mTOR signal-pathway activation. © 2017 The Author(s). Published by S. Karger AG, Basel.

  5. Globular Adiponectin Attenuated H2O2-Induced Apoptosis in Rat Chondrocytes by Inducing Autophagy Through the AMPK/ mTOR Pathway

    Directory of Open Access Journals (Sweden)

    Junzheng Hu

    2017-08-01

    H2O2-induced chondrocytes apoptosis by gAPN. Conclusions: gAPN protected chondrocytes from H2O2-induced apoptosis by inducing autophagy possibly associated with AMPK/mTOR signal-pathway activation.

  6. Probing the canonicity of the Wnt/Wingless signaling pathway.

    Directory of Open Access Journals (Sweden)

    Alexandra Franz

    2017-04-01

    Full Text Available The hallmark of canonical Wnt signaling is the transcriptional induction of Wnt target genes by the beta-catenin/TCF complex. Several studies have proposed alternative interaction partners for beta-catenin or TCF, but the relevance of potential bifurcations in the distal Wnt pathway remains unclear. Here we study on a genome-wide scale the requirement for Armadillo (Arm, Drosophila beta-catenin and Pangolin (Pan, Drosophila TCF in the Wnt/Wingless(Wg-induced transcriptional response of Drosophila Kc cells. Using somatic genetics, we demonstrate that both Arm and Pan are absolutely required for mediating activation and repression of target genes. Furthermore, by means of STARR-sequencing we identified Wnt/Wg-responsive enhancer elements and found that all responsive enhancers depend on Pan. Together, our results confirm the dogma of canonical Wnt/Wg signaling and argue against the existence of distal pathway branches in this system.

  7. Aberrant Signaling Pathways in T-Cell Acute Lymphoblastic Leukemia

    Science.gov (United States)

    Bongiovanni, Deborah; Saccomani, Valentina

    2017-01-01

    T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive disease caused by the malignant transformation of immature progenitors primed towards T-cell development. Clinically, T-ALL patients present with diffuse infiltration of the bone marrow by immature T-cell blasts high blood cell counts, mediastinal involvement, and diffusion to the central nervous system. In the past decade, the genomic landscape of T-ALL has been the target of intense research. The identification of specific genomic alterations has contributed to identify strong oncogenic drivers and signaling pathways regulating leukemia growth. Notwithstanding, T-ALL patients are still treated with high-dose multiagent chemotherapy, potentially exposing these patients to considerable acute and long-term side effects. This review summarizes recent advances in our understanding of the signaling pathways relevant for the pathogenesis of T-ALL and the opportunities offered for targeted therapy. PMID:28872614

  8. Signaling Pathways Related to Protein Synthesis and Amino Acid Concentration in Pig Skeletal Muscles Depend on the Dietary Protein Level, Genotype and Developmental Stages.

    Science.gov (United States)

    Liu, Yingying; Li, Fengna; Kong, Xiangfeng; Tan, Bie; Li, Yinghui; Duan, Yehui; Blachier, François; Hu, Chien-An A; Yin, Yulong

    2015-01-01

    Muscle growth is regulated by the homeostatic balance of the biosynthesis and degradation of muscle proteins. To elucidate the molecular interactions among diet, pig genotype, and physiological stage, we examined the effect of dietary protein concentration, pig genotype, and physiological stages on amino acid (AA) pools, protein deposition, and related signaling pathways in different types of skeletal muscles. The study used 48 Landrace pigs and 48 pure-bred Bama mini-pigs assigned to each of 2 dietary treatments: lower/GB (Chinese conventional diet)- or higher/NRC (National Research Council)-protein diet. Diets were fed from 5 weeks of age to respective market weights of each genotype. Samples of biceps femoris muscle (BFM, type I) and longissimus dorsi muscle (LDM, type II) were collected at nursery, growing, and finishing phases according to the physiological stage of each genotype, to determine the AA concentrations, mRNA levels for growth-related genes in muscles, and protein abundances of mechanistic target of rapamycin (mTOR) signaling pathway. Our data showed that the concentrations of most AAs in LDM and BFM of pigs increased (Prelated AA, including Met, Phe, Tyr, Pro, and Ser, compared with Landrace pigs. The mRNA levels for myogenic determining factor, myogenin, myocyte-specific enhancer binding factor 2 A, and myostatin of Bama mini-pigs were higher (P<0.05) than those of Landrace pigs, while total and phosphorylated protein levels for protein kinase B, mTOR, and p70 ribosomal protein S6 kinases (p70S6K), and ratios of p-mTOR/mTOR, p-AKT/AKT, and p-p70S6K/p70S6K were lower (P<0.05). There was a significant pig genotype-dependent effect of dietary protein on the levels for mTOR and p70S6K. When compared with the higher protein-NRC diet, the lower protein-GB diet increased (P<0.05) the levels for mTOR and p70S6K in Bama mini-pigs, but repressed (P<0.05) the level for p70S6K in Landrace pigs. The higher protein-NRC diet increased ratio of p-mTOR/mTOR in

  9. GAS6/TAM Pathway Signaling in Hemostasis and Thrombosis.

    Science.gov (United States)

    Law, Luke A; Graham, Douglas K; Di Paola, Jorge; Branchford, Brian R

    2018-01-01

    The GAS6/TYRO3-AXL-MERTK (TAM) signaling pathway is essential for full and sustained platelet activation, as well as thrombus stabilization. Inhibition of this pathway decreases platelet aggregation, shape change, clot retraction, aggregate formation under flow conditions, and surface expression of activation markers. Transgenic mice deficient in GAS6, or any of the TAM family of receptors that engage this ligand, exhibit in vivo protection against arterial and venous thrombosis but do not demonstrate either spontaneous or prolonged bleeding compared to their wild-type counterparts. Comparable results are observed in wild-type mice treated with pharmacological inhibitors of the GAS6-TAM pathway. Thus, GAS6/TAM inhibition offers an attractive novel therapeutic option that may allow for a moderate reduction in platelet activation and decreased thrombosis while still permitting the primary hemostatic function of platelet plug formation.

  10. Inflammation Activates the Interferon Signaling Pathways in Taste Bud Cells

    OpenAIRE

    Wang, Hong; Zhou, Minliang; Brand, Joseph; Huang, Liquan

    2007-01-01

    Patients with viral and bacterial infections or other inflammatory illnesses often experience taste dysfunctions. The agents responsible for these taste disorders are thought to be related to infection-induced inflammation, but the mechanisms are not known. As a first step in characterizing the possible role of inflammation in taste disorders, we report here evidence for the presence of interferon (IFN)-mediated signaling pathways in taste bud cells. IFN receptors, particularly the IFN-γ rece...

  11. Herpes simplex virus triggers activation of calcium-signaling pathways

    Science.gov (United States)

    Cheshenko, Natalia; Del Rosario, Brian; Woda, Craig; Marcellino, Daniel; Satlin, Lisa M.; Herold, Betsy C.

    2003-01-01

    The cellular pathways required for herpes simplex virus (HSV) invasion have not been defined. To test the hypothesis that HSV entry triggers activation of Ca2+-signaling pathways, the effects on intracellular calcium concentration ([Ca2+]i) after exposure of cells to HSV were examined. Exposure to virus results in a rapid and transient increase in [Ca2+]i. Pretreatment of cells with pharmacological agents that block release of inositol 1,4,5-triphosphate (IP3)–sensitive endoplasmic reticulum stores abrogates the response. Moreover, treatment of cells with these pharmacological agents inhibits HSV infection and prevents focal adhesion kinase (FAK) phosphorylation, which occurs within 5 min after viral infection. Viruses deleted in glycoprotein L or glycoprotein D, which bind but do not penetrate, fail to induce a [Ca2+]i response or trigger FAK phosphorylation. Together, these results support a model for HSV infection that requires activation of IP3-responsive Ca2+-signaling pathways and that is associated with FAK phosphorylation. Defining the pathway of viral invasion may lead to new targets for anti-viral therapy. PMID:14568989

  12. mTOR Inhibition Induces EGFR Feedback Activation in Association with Its Resistance to Human Pancreatic Cancer

    Directory of Open Access Journals (Sweden)

    Feng Wei

    2015-02-01

    Full Text Available The mammalian target of rapamycin (mTOR is dysregulated in diverse cancers and contributes to tumor progression and drug resistance. The first generation of mTOR inhibitors have failed to show clinical efficiency in treating pancreatic cancers due in part to the feedback relief of the insulin-like growth factor-1 receptor (IGF-1R-AKT signaling pathway. The second generation of mTOR inhibitors, such as AZD8055, could inhibit AKT activation upon mTOR complex 2 (mTORC2 inhibition. However, whether this generation of mTOR inhibitors can obtain satisfactory activities in pancreatic cancer therapy remains unclear. In this study, we found AZD8055 did not show great improvement compared with everolimus, AZD8055 induced a temporal inhibition of AKT kinase activities and AKT was then rephosphorylated. Additionally, we found that AZD8055-induced transient AKT inhibition increased the expression and activation of epidermal growth factor receptor (EGFR by releasing its transcriptional factors Fork-head box O 1/3a (FoxO1/3a, which might contribute to cell resistance to AZD8055. The in vitro and in vivo experiments further indicated the combination of AZD8055 and erlotinib synergistically inhibited the mTORC1/C2 signaling pathway, EGFR/AKT feedback activation, and cell growth, as well as suppressed the progression of pancreatic cancer in a xenograft model. This study provides a rationale and strategy for overcoming AZD8055 resistance by a combined treatment with the EGFR inhibitor erlotinib in pancreatic cancer therapy.

  13. Differential Reponses of Hematopoietic Stem and Progenitor Cells to mTOR Inhibition

    Directory of Open Access Journals (Sweden)

    Aimin Yang

    2015-01-01

    Full Text Available Abnormal activation of the mammalian target of rapamycin (mTOR signaling pathway has been observed in a variety of human cancers. Therefore, targeting of the mTOR pathway is an attractive strategy for cancer treatment and several mTOR inhibitors, including AZD8055 (AZD, a novel dual mTORC1/2 inhibitor, are currently in clinical trials. Although bone marrow (BM suppression is one of the primary side effects of anticancer drugs, it is not known if pharmacological inhibition of dual mTORC1/2 affects BM hematopoietic stem and progenitor cells (HSPCs function and plasticity. Here we report that dual inhibition of mTORC1/2 by AZD or its analogue (KU-63794 depletes mouse BM Lin−Sca-1+c-Kit+ cells in cultures via the induction of apoptotic cell death. Subsequent colony-forming unit (CFU assays revealed that inhibition of mTORC1/2 suppresses the clonogenic function of hematopoietic progenitor cells (HPCs in a dose-dependent manner. Surprisingly, we found that dual inhibition of mTORC1/2 markedly inhibits the growth of day-14 cobblestone area-forming cells (CAFCs but enhances the generation of day-35 CAFCs. Given the fact that day-14 and day-35 CAFCs are functional surrogates of HPCs and hematopoietic stem cells (HSCs, respectively, these results suggest that dual inhibition of mTORC1/2 may have distinct effects on HPCs versus HSCs.

  14. Combined inhibition of p38 and Akt signaling pathways abrogates cyclosporine A-mediated pathogenesis of aggressive skin SCCs

    Energy Technology Data Exchange (ETDEWEB)

    Arumugam, Aadithya; Walsh, Stephanie B.; Xu, Jianmin; Afaq, Farrukh [Department of Dermatology, University of Alabama at Birmingham, Birmingham, AL 35294-0019 (United States); Elmets, Craig A. [Department of Dermatology, University of Alabama at Birmingham, Birmingham, AL 35294-0019 (United States); Skin Diseases Research Center, University of Alabama at Birmingham, Birmingham, AL 35294 (United States); Athar, Mohammad, E-mail: mathar@uab.edu [Department of Dermatology, University of Alabama at Birmingham, Birmingham, AL 35294-0019 (United States); Skin Diseases Research Center, University of Alabama at Birmingham, Birmingham, AL 35294 (United States)

    2012-08-24

    Highlights: Black-Right-Pointing-Pointer p38 and Akt are the crucial molecular targets in the pathogenesis of SCCs in OTRs. Black-Right-Pointing-Pointer Combined inhibition of these targets diminished tumor growth by 90%. Black-Right-Pointing-Pointer Inhibition of these targets act through downregulating mTOR signaling pathway. -- Abstract: Non-melanoma skin cancers (NMSCs) are the most common neoplasm in organ transplant recipients (OTRs). These cancers are more invasive and metastatic as compared to those developed in normal cohorts. Previously, we have shown that immunosuppressive drug, cyclosporine A (CsA) directly alters tumor phenotype of cutaneous squamous cell carcinomas (SCCs) by activating TGF-{beta} and TAK1/TAB1 signaling pathways. Here, we identified novel molecular targets for the therapeutic intervention of these SCCs. We observed that combined blockade of Akt and p38 kinases-dependent signaling pathways in CsA-promoted human epidermoid carcinoma A431 xenograft tumors abrogated their growth by more than 90%. This diminution in tumor growth was accompanied by a significant decrease in proliferation and an increase in apoptosis. The residual tumors following the combined treatment with Akt inhibitor triciribine and p38 inhibitors SB-203580 showed significantly diminished expression of phosphorylated Akt and p38 and these tumors were less invasive and highly differentiated. Diminished tumor invasiveness was associated with the reduced epithelial-mesenchymal transition as ascertained by the enhanced E-cadherin and reduced vimentin and N-cadherin expression. Consistently, these tumors also manifested reduced MMP-2/9. The decreased p-Akt expression was accompanied by a significant reduction in p-mTOR. These data provide first important combinatorial pharmacological approach to block the pathogenesis of CsA-induced highly aggressive cutaneous neoplasm in OTRs.

  15. Interleukins and their signaling pathways in the Reactome biological pathway database.

    Science.gov (United States)

    Jupe, Steve; Ray, Keith; Roca, Corina Duenas; Varusai, Thawfeek; Shamovsky, Veronica; Stein, Lincoln; D'Eustachio, Peter; Hermjakob, Henning

    2018-04-01

    much molecular detail as possible and are linked to literature citations that contain supporting experimental details. All newly created events undergo a peer-review process before they are added to the database and made available on the associated Web site. New content is added quarterly. The 63rd release of Reactome in December 2017 contains 10,996 human proteins participating in 11,426 events in 2,179 pathways. In addition, analytic tools allow data set submission for the identification and visualization of pathway enrichment and representation of expression profiles as an overlay on Reactome pathways. Protein-protein and compound-protein interactions from several sources, including custom user data sets, can be added to extend pathways. Pathway diagrams and analytic result displays can be downloaded as editable images, human-readable reports, and files in several standard formats that are suitable for computational reuse. Reactome content is available programmatically through a REpresentational State Transfer (REST)-based content service and as a Neo4J graph database. Signaling pathways for IL-1 to IL-38 are hierarchically classified within the pathway "signaling by interleukins." The classification used is largely derived from Akdis et al. The addition to Reactome of a complete set of the known human interleukins, their receptors, and established signaling pathways linked to annotations of relevant aspects of immune function provides a significant computationally accessible resource of information about this important family. This information can be extended easily as new discoveries become accepted as the consensus in the field. A key aim for the future is to increase coverage of gene expression changes induced by interleukin signaling. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

  16. Nasopharyngeal Carcinoma Signaling Pathway: An Update on Molecular Biomarkers

    Directory of Open Access Journals (Sweden)

    Warut Tulalamba

    2012-01-01

    Full Text Available Nasopharyngeal carcinoma (NPC is an uncommon cancer, which has a distinctive ethnic and geographic distribution. Etiology of NPC is considered to be related with a complex interaction of environmental and genetic factors as well as Epstein-Barr virus infection. Since NPC is located in the silent painless area, the disease is usually therefore diagnosed at the advanced stages; hence early detection of NPC is difficult. Furthermore, understanding in molecular pathogenesis is still lacking, pondering the identification of effective prognostic and diagnostic biomarkers. Dysregulation of signaling molecules in intracellular signal transduction, which regulate cell proliferation, apoptosis, and adhesion, underlines the basis of NPC pathogenesis. In this paper, the molecular signaling pathways in the NPC are discussed for the holistic view of NPC development and progression. The important insights toward NPC pathogenesis may offer strategies for identification of novel biomarkers for diagnosis and prognosis.

  17. Pentagone internalises glypicans to fine-tune multiple signalling pathways

    Science.gov (United States)

    Norman, Mark; Vuilleumier, Robin; Springhorn, Alexander; Gawlik, Jennifer; Pyrowolakis, George

    2016-01-01

    Tight regulation of signalling activity is crucial for proper tissue patterning and growth. Here we investigate the function of Pentagone (Pent), a secreted protein that acts in a regulatory feedback during establishment and maintenance of BMP/Dpp morphogen signalling during Drosophila wing development. We show that Pent internalises the Dpp co-receptors, the glypicans Dally and Dally-like protein (Dlp), and propose that this internalisation is important in the establishment of a long range Dpp gradient. Pent-induced endocytosis and degradation of glypicans requires dynamin- and Rab5, but not clathrin or active BMP signalling. Thus, Pent modifies the ability of cells to trap and transduce BMP by fine-tuning the levels of the BMP reception system at the plasma membrane. In addition, and in accordance with the role of glypicans in multiple signalling pathways, we establish a requirement of Pent for Wg signalling. Our data propose a novel mechanism by which morphogen signalling is regulated. DOI: http://dx.doi.org/10.7554/eLife.13301.001 PMID:27269283

  18. Signal Transduction Pathways of TNAP: Molecular Network Analyses.

    Science.gov (United States)

    Négyessy, László; Györffy, Balázs; Hanics, János; Bányai, Mihály; Fonta, Caroline; Bazsó, Fülöp

    2015-01-01

    Despite the growing body of evidence pointing on the involvement of tissue non-specific alkaline phosphatase (TNAP) in brain function and diseases like epilepsy and Alzheimer's disease, our understanding about the role of TNAP in the regulation of neurotransmission is severely limited. The aim of our study was to integrate the fragmented knowledge into a comprehensive view regarding neuronal functions of TNAP using objective tools. As a model we used the signal transduction molecular network of a pyramidal neuron after complementing with TNAP related data and performed the analysis using graph theoretic tools. The analyses show that TNAP is in the crossroad of numerous pathways and therefore is one of the key players of the neuronal signal transduction network. Through many of its connections, most notably with molecules of the purinergic system, TNAP serves as a controller by funnelling signal flow towards a subset of molecules. TNAP also appears as the source of signal to be spread via interactions with molecules involved among others in neurodegeneration. Cluster analyses identified TNAP as part of the second messenger signalling cascade. However, TNAP also forms connections with other functional groups involved in neuronal signal transduction. The results indicate the distinct ways of involvement of TNAP in multiple neuronal functions and diseases.

  19. Leucine Supplementation in a Chronically Protein-Restricted Diet Enhances Muscle Weight and Postprandial Protein Synthesis of Skeletal Muscle by Promoting the mTOR Pathway in Adult Rats

    Directory of Open Access Journals (Sweden)

    Bo Zhang

    2017-10-01

    Full Text Available Low protein intake causes a decrease in protein deposition in most animal tissues. The purpose of this study was to investigate whether leucine supplementation would increase the synthesis rate of protein and muscle weight in adult rats, which chronically consume only 58.8% of their protein requirements. Thirty-six male Sprague-Dawley rats were assigned to one of three dietary treatments including a 20% casein diet (CON, a 10% casein + 0.44% alanine diet (R, and a 10% casein + 0.87% leucine diet (RL. After a 10 d dietary treatment, plasma amino acid levels were measured after feeding, the gastrocnemius muscles and soleus muscles were harvested and weighed, and the fractional synthesis rate (FSR and mammalian target of rapamycin (mTOR signaling proteins in skeletal muscle were measured. Regarding the plasma amino acid level, the RL group had the highest concentration of leucine (P < 0.05 and the lowest concentration of isoleucine (P < 0.05 among the three groups, and the CON group had a lower concentration of valine (P < 0.05 than the R and RL groups. Compared with the R and RL groups, the CON group diet significantly increased (P < 0.05 feed intake, protein synthesis rate, and the phosphorylation of eukaryotic initiation factor 4E binding protein 1 (4E-BP1, and decreased the weight of abdominal adipose. Compared with the R group, the RL group significantly increased in gastrocnemius muscle weight, protein synthesis rate, and phosphorylation of both ribosomal protein S6 kinase 1 (S6K1 and 4E-BP1. In conclusion, when protein is chronically restricted in adult rat diets, leucine supplementation moderately improves body weight gain and increases muscle protein synthesis through mTOR activation.

  20. Romidepsin targets multiple survival signaling pathways in malignant T cells

    International Nuclear Information System (INIS)

    Valdez, B C; Brammer, J E; Li, Y; Murray, D; Liu, Y; Hosing, C; Nieto, Y; Champlin, R E; Andersson, B S

    2015-01-01

    Romidepsin is a cyclic molecule that inhibits histone deacetylases. It is Food and Drug Administration-approved for treatment of cutaneous and peripheral T-cell lymphoma, but its precise mechanism of action against malignant T cells is unknown. To better understand the biological effects of romidepsin in these cells, we exposed PEER and SUPT1 T-cell lines, and a primary sample from T-cell lymphoma patient (Patient J) to romidepsin. We then examined the consequences in some key oncogenic signaling pathways. Romidepsin displayed IC 50 values of 10.8, 7.9 and 7.0 nm in PEER, SUPT1 and Patient J cells, respectively. Strong inhibition of histone deacetylases and demethylases, increased production of reactive oxygen species and decreased mitochondrial membrane potential were observed, which may contribute to the observed DNA-damage response and apoptosis. The stress-activated protein kinase/c-Jun N-terminal kinase signaling pathway and unfolded protein response in the endoplasmic reticulum were activated, whereas the phosphatidylinositol 3-kinase/AKT/mammalian target of rapamycin (PI3K/AKT/mTOR) and β-catenin pro-survival pathways were inhibited. The decreased level of β-catenin correlated with the upregulation of its inhibitor SFRP1 through romidepsin-mediated hypomethylation of its gene promoter. Our results provide new insights into how romidepsin invokes malignant T-cell killing, show evidence of its associated DNA hypomethylating activity and offer a rationale for the development of romidepsin-containing combination therapies

  1. The interplay of CD150 and CD180 receptor pathways contribute to the pathobiology of chronic lymphocytic leukemia B cells by selective inhibition of Akt and MAPK signaling.

    Directory of Open Access Journals (Sweden)

    Inna Gordiienko

    Full Text Available Cell surface expression of CD150 and CD180 receptors in chronic lymphocytic leukemia (CLL associates with mutational IGHV status and favourable prognosis. Here we show a direct correlation between cell surface expression and colocalization of these receptors on CLL B cells. In the absence of CD150 and CD180 on the cell surface both receptors were expressed in the cytoplasm. The CD150 receptor was colocalized with markers of the endoplasmic reticulum, the Golgi apparatus and early endosomes. In contrast, CD180 was detected preferentially in early endosomes. Analysis of CD150 isoforms differential expression revealed that regardless of CD150 cell surface expression the mCD150 isoform with two ITSM signaling motifs was a predominant CD150 isoform in CLL B cells. The majority of CLL cases had significantly elevated expression level of the soluble sCD150, moreover CLL B cells secrete this isoform. CD150 or CD180 crosslinking on CLL B cells alone led to activation of Akt, mTORC1, ERK1/2, p38MAPK and JNK1/2 networks. Both CD150 and CD180 target the translation machinery through mTOR independent as well as mTOR dependent pathways. Moreover, both these receptors transmit pro-survival signals via Akt-mediated inhibition of GSK3β and FOXO1/FOXO3a. Unexpectedly, coligation CD150 and CD180 receptors on CLL B cells led to mutual inhibition of the Akt and MAPK pathways. While CD150 and CD180 coligation resulted in reduced phosphorylation of Akt, ERK1/2, c-Jun, RSK, p70S6K, S6RP, and 4E-BP; it led to complete blocking of mTOR and p38MAPK phosphorylation. At the same time coligation of CD150 and CD40 receptors did not result in Akt and MAPK inhibition. This suggests that combination of signals via CD150 and CD180 leads to blocking of pro-survival pathways that may be a restraining factor for neoplastic CLL B cells propagation in more than 50% of CLL cases where these receptors are coexpressed.

  2. Prevotella intermedia induces prostaglandin E2 via multiple signaling pathways.

    Science.gov (United States)

    Guan, S-M; Fu, S-M; He, J-J; Zhang, M

    2011-01-01

    Prostaglandin E(2) (PGE(2)) plays important roles in the bone resorption of inflammatory diseases such as rheumatoid arthritis and periodontitis via specific prostaglandin receptors (i.e., EP1-EP4). In this study, the authors examined whether Prevotella intermedia regulates PGE(2) production and EP expression in human periodontal ligament fibroblasts (hPDLs); they also explored the potential signaling pathways involved in PGE(2) production. P. intermedia induced PGE(2) production and cyclooxygenase-2 (COX-2) expression in a dose- and time-dependent manner. Indomethacin and NS-398 completely abrogated the P. intermedia-induced PGE(2) production without modulating COX-2 expression. Specific inhibitors of extracellular signal-regulated kinase, c-Jun N-terminal kinase, p38, phosphatidylinositol 3-kinase, and protein kinase C--but not c-AMP and protein kinase A--significantly attenuated the P. intermedia-induced COX-2 and PGE(2) expression. P. intermedia reduced EP1 expression in a concentration- and time-dependent manner. The results indicate that the COX-2-dependent induction of PGE(2) by P. intermedia in hPDLs is mediated by multiple signaling pathways.

  3. Calcium-Dependent Protein Kinases in Phytohormone Signaling Pathways

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    Wuwu Xu

    2017-11-01

    Full Text Available Calcium-dependent protein kinases (CPKs/CDPKs are Ca2+-sensors that decode Ca2+ signals into specific physiological responses. Research has reported that CDPKs constitute a large multigene family in various plant species, and play diverse roles in plant growth, development, and stress responses. Although numerous CDPKs have been exhaustively studied, and many of them have been found to be involved in plant hormone biosynthesis and response mechanisms, a comprehensive overview of the manner in which CDPKs participate in phytohormone signaling pathways, regulating nearly all aspects of plant growth, has not yet been undertaken. In this article, we reviewed the structure of CDPKs and the mechanism of their subcellular localization. Some CDPKs were elucidated to influence the intracellular localization of their substrates. Since little work has been done on the interaction between CDPKs and cytokinin signaling pathways, or on newly defined phytohormones such as brassinosteroids, strigolactones and salicylic acid, this paper mainly focused on discussing the integral associations between CDPKs and five plant hormones: auxins, gibberellins, ethylene, jasmonates, and abscisic acid. A perspective on future work is provided at the end.

  4. Notch pathway signaling in the skin antagonizes Merkel cell development.

    Science.gov (United States)

    Logan, Gregory J; Wright, Margaret C; Kubicki, Adam C; Maricich, Stephen M

    2018-02-15

    Merkel cells are mechanosensitive skin cells derived from the epidermal lineage whose development requires expression of the basic helix-loop-helix transcription factor Atoh1. The genes and pathways involved in regulating Merkel cell development during embryogenesis are poorly understood. Notch pathway signaling antagonizes Atoh1 expression in many developing body regions, so we hypothesized that Notch signaling might inhibit Merkel cell development. We found that conditional, constitutive overexpression of the Notch intracellular domain (NICD) in mouse epidermis significantly decreased Merkel cell numbers in whisker follicles and touch domes of hairy skin. Conversely, conditional deletion of the obligate NICD binding partner RBPj in the epidermis significantly increased Merkel cell numbers in whisker follicles, led to the development of ectopic Merkel cells outside of touch domes in hairy skin epidermis, and altered the distribution of Merkel cells in touch domes. Deletion of the downstream Notch effector gene Hes1 also significantly increased Merkel cell numbers in whisker follicles. Together, these data demonstrate that Notch signaling regulates Merkel cell production and patterning. Copyright © 2018 Elsevier Inc. All rights reserved.

  5. Radiation-induced adaptive response and intracellular signal transduction pathways

    International Nuclear Information System (INIS)

    Tachibana, Akira

    2009-01-01

    As an essential biological function, cells can sense the radiation even at low dose and respond to it, and which is one of bases of the radiation-induced adaptive response (AR) where effects caused by high dose radiation are reduced by prior exposure to low dose radiation (LDR). Here described are studies of AR in well established m5S cells on the intracellular signal transduction that involves sensing of LDR and transmitting of its signal within the cell network. The first signal for AR yielded by LDR on the cell membrane is exactly unknown though hydrogen peroxide and phorbol ester (PMA) can reportedly cause AR. As PMA activates protein kinase C (PKC) and its inhibitors suppress AR, participation of PKC in AR has been suggested and supported by studies showing PKCα activation by LDR. In addition, p38 mitogen-activated protein kinase (MAPK) is shown to participate in AR by those facts that the enzyme is activated by LDR, a p38 MAPK inhibitor suppresses AR, and PKC inhibitors suppress the enzyme activation, which also suggesting that the signaling from PKC to p38 MAPK can become operative by LDR. However, the possible reverse signaling is also suggested, and thus the activation of positive feedback mechanism is postulated in PKC/p38 MAPK/phospholipase δ1/ PKC pathway. Cells introduced with siRNA against Prkca gene (coding PKCs) produce reduced amount of the enzyme, particularly, of PKCα. In those cells, AR by 5 Gy X-ray is not observed and thereby PKCα is involved in AR. The signaling in AR is only partly elucidated at present as above, and more detailed studies including identification of more PKC subtypes and signaling to DNA repair system are considered necessary. (K.T.)

  6. miR-155 Controls Lymphoproliferation in LAT Mutant Mice by Restraining T-Cell Apoptosis via SHIP-1/mTOR and PAK1/FOXO3/BIM Pathways.

    Directory of Open Access Journals (Sweden)

    Alexandre K Rouquette-Jazdanian

    Full Text Available Linker for Activation of T cells (LAT is an adapter protein that is essential for T cell function. Knock-in mice with a LAT mutation impairing calcium flux develop a fatal CD4+ lymphoproliferative disease. miR-155 is a microRNA that is correlated with hyperproliferation in a number of cancers including lymphomas and leukemias and is overexpressed in mutant LAT T cells. To test whether miR-155 was merely indicative of T cell activation or whether it contributes to lymphoproliferative disease in mutant LAT mice, we interbred LAT mutant and miR-155-deficient mice. miR-155 deficiency markedly inhibited lymphoproliferative disease by stimulating BIM-dependent CD4+ T cell apoptosis, even though ERK activation and T cell proliferation were increased in double mutant CD4+ T cells. Bim/Bcl2l11 expression is activated by the forkhead transcription factor FOXO3. Using miR-155-deficient, LAT mutant T cells as a discovery tool, we found two connected pathways that impact the nuclear translocation and activation of FOXO3 in T cells. One pathway is mediated by the inositide phosphatase SHIP-1 and the serine/threonine kinases AKT and PDK1. The other pathway involves PAK1 and JNK kinase activation. We define crosstalk between the two pathways via the kinase mTOR, which stabilizes PAK1. This study establishes a role for PAK1 in T cell apoptosis, which contrasts to its previously identified role in T cell proliferation. Furthermore, miR-155 regulates the delicate balance between PAK1-mediated proliferation and apoptosis in T cells impacting lymphoid organ size and function.

  7. L-Arginine Enhances Protein Synthesis by Phosphorylating mTOR (Thr 2446 in a Nitric Oxide-Dependent Manner in C2C12 Cells

    Directory of Open Access Journals (Sweden)

    Ruxia Wang

    2018-01-01

    Full Text Available Muscle atrophy may arise from many factors such as inactivity, malnutrition, and inflammation. In the present study, we investigated the stimulatory effect of nitric oxide (NO on muscle protein synthesis. Primarily, C2C12 cells were supplied with extra L-arginine (L-Arg in the culture media. L-Arg supplementation increased the activity of inducible nitric oxide synthase (iNOS, the rate of protein synthesis, and the phosphorylation of mTOR (Thr 2446 and p70S6K (Thr 389. L-NAME, an NOS inhibitor, decreased NO concentrations within cells and abolished the stimulatory effect of L-Arg on protein synthesis and the phosphorylation of mTOR and p70S6K. In contrast, SNP (sodium nitroprusside, an NO donor, increased NO concentrations, enhanced protein synthesis, and upregulated mTOR and p70S6K phosphorylation, regardless of L-NAME treatment. Blocking mTOR with rapamycin abolished the stimulatory effect of both L-Arg and SNP on protein synthesis and p70S6K phosphorylation. These results indicate that L-Arg stimulates protein synthesis via the activation of the mTOR (Thr 2446/p70S6K signaling pathway in an NO-dependent manner.

  8. TSC1 and TSC2 regulate cilia length and canonical Hedgehog signaling via different mechanisms

    DEFF Research Database (Denmark)

    Rosengren, Thomas; Larsen, Lasse Jonsgaard; Pedersen, Lotte Bang

    2018-01-01

    Primary cilia are sensory organelles that coordinate multiple cellular signaling pathways, including Hedgehog (HH), Wingless/Int (WNT) and Transforming Growth Factor-β (TGF-β) signaling. Similarly, primary cilia have been implicated in regulation of mTOR signaling, in which Tuberous Sclerosis Com...

  9. Interleukin-2 signaling pathway analysis by quantitative phosphoproteomics

    DEFF Research Database (Denmark)

    Osinalde, Nerea; Moss, Helle; Arrizabalaga, Onetsine

    2011-01-01

    among which 79 were found with increased abundance in the tyrosine-phosphorylated complexes, including several previously not reported IL-2 downstream effectors. Combinatorial site-specific phosphoproteomic analysis resulted in identification of 99 phosphorylated sites mapping to the identified proteins...... with increased abundance in the tyrosine-phosphorylated complexes, of which 34 were not previously described. In addition, chemical inhibition of the identified IL-2-mediated JAK, PI3K and MAPK signaling pathways, resulted in distinct alteration on the IL-2 dependent proliferation....

  10. Understanding Resolvin Signaling Pathways to Improve Oral Health

    Directory of Open Access Journals (Sweden)

    Laura De Oleo

    2013-03-01

    Full Text Available The discovery of resolvins has been a major breakthrough for understanding the processes involved in resolution of inflammation. Resolvins belong to a family of novel lipid mediators that possess dual anti-inflammatory and pro-resolution actions. Specifically, they protect healthy tissue during immune-inflammatory responses to infection or injury, thereby aiding inflammation resolution and promoting tissue healing. One of the major concerns in modern medicine is the management and treatment of oral diseases, as they are related to systemic outcomes impacting the quality of life of many patients. This review summarizes known signaling pathways utilized by resolvins to regulate inflammatory responses associated with the oral cavity.

  11. GDF15 regulates Kv2.1-mediated outward K+ current through the Akt/mTOR signalling pathway in rat cerebellar granule cells.

    Science.gov (United States)

    Wang, Chang-Ying; Huang, An-Qi; Zhou, Meng-Hua; Mei, Yan-Ai

    2014-05-15

    GDF15 (growth/differentiation factor 15), a novel member of the TGFβ (transforming growth factor β) superfamily, plays critical roles in the central and peripheral nervous systems, but the signal transduction pathways and receptor subtypes involved are not well understood. In the present paper, we report that GDF15 specifically increases the IK (delayed-rectifier outward K+ current) in rat CGNs (cerebellar granule neurons) in time- and concentration-dependent manners. The GDF15-induced amplification of the IK is mediated by the increased expression and reduced lysosome-dependent degradation of the Kv2.1 protein, the main α-subunit of the IK channel. Exposure of CGNs to GDF15 markedly induced the phosphorylation of ERK (extracellular-signal-regulated kinase), Akt and mTOR (mammalian target of rapamycin), but the GDF15-induced IK densities and increased expression of Kv2.1 were attenuated only by Akt and mTOR, and not ERK, inhibitors. Pharmacological inhibition of the Src-mediated phosphorylation of TGFβR2 (TGFβ receptor 2), not TGFβR1, abrogated the effect of GDF15 on IK amplification and Kv2.1 induction. Immunoprecipitation assays showed that GDF15 increased the tyrosine phosphorylation of TGFβRII in the CGN lysate. The results of the present study reveal a novel regulation of Kv2.1 by GDF15 mediated through the TGFβRII-activated Akt/mTOR pathway, which is a previously uncharacterized Smad-independent mechanism of GDF15 signalling.

  12. Expression of factors and key components associated with the PI3K signaling pathway in colon cancer.

    Science.gov (United States)

    Chen, Hua; Gao, Junyi; Du, Zhenhua; Zhang, Xuequn; Yang, Fei; Gao, Wei

    2018-04-01

    The pathophysiology of colorectal cancer (CRC) has not been fully elucidated. The dysregulation of the phosphatidylinositol 3-kinase (PI3K) signaling pathway frequently contributes to the tumorigenesis and progression of human cancer. The aim of the present study was to explore the expression and clinical significance of a number of associated factors and key components of the PI3K signaling pathway, including phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit α (p110α), phosphorylated protein kinase B (p-Akt) Ser473, p-mammalian target of rapamycin (mTOR) Ser2448, cyclin D1, cyclin dependent kinase (CDK)4, RELA proto-oncogene, nuclear factor-κβ subunit (p65), Ras and extracellular signal-regulated kinase (ERK)1/2 in human CRC. The expression of target proteins was detected using immunohistochemistry (IHC) in 65 CRC cases and 15 colonic adenoma cases. The association between the expression of target proteins and clinical pathological parameters was analyzed using a χ 2 test. IHC results revealed that the expression of all target proteins was significantly increased in CRC tissues compared with in colonic adenoma tissues (P0.05). Cyclin D1, CDK4 and Ras were revealed to be expressed significantly higher in poorly differentiated CRC compared with moderately differentiated CRC (Pcancer tissues with lymph node metastasis compared with cancer tissues without lymph node metastasis (P<0.05). These results suggest that the target proteins may all participate in the tumorigenesis of CRC. Furthermore, cyclin D1, CDK4, Ras, p65 and ERK1/2 may be important in the progression of CRC. The results of the present study may provide novel predictive factors and therapeutic targets for CRC.

  13. Methamphetamine exposure triggers apoptosis and autophagy in neuronal cells by activating the C/EBPβ-related signaling pathway.

    Science.gov (United States)

    Xu, Xiang; Huang, Enping; Luo, Baoying; Cai, Dunpeng; Zhao, Xu; Luo, Qin; Jin, Yili; Chen, Ling; Wang, Qi; Liu, Chao; Lin, Zhoumeng; Xie, Wei-Bing; Wang, Huijun

    2018-06-25

    Methamphetamine (Meth) is a widely abused psychoactive drug that primarily damages the nervous system, notably causing dopaminergic neuronal apoptosis. CCAAT-enhancer binding protein (C/EBPβ) is a transcription factor and an important regulator of cell apoptosis and autophagy. Insulin-like growth factor binding protein (IGFBP5) is a proapoptotic factor that mediates Meth-induced neuronal apoptosis, and Trib3 (tribbles pseudokinase 3) is an endoplasmic reticulum (ER) stress-inducible gene involved in autophagic cell death through the mammalian target of rapamycin (mTOR) signaling pathway. To test the hypothesis that C/EBPβ is involved in Meth-induced IGFBP5-mediated neuronal apoptosis and Trib3-mediated neuronal autophagy, we measured the protein expression of C/EBPβ after Meth exposure and evaluated the effects of silencing C/EBPβ, IGFBP5, or Trib3 on Meth-induced apoptosis and autophagy in neuronal cells and in the rat striatum after intrastriatal Meth injection. We found that, at relatively high doses, Meth exposure increased C/EBPβ protein expression, which was accompanied by increased neuronal apoptosis and autophagy; triggered the IGFBP5-mediated, p53-up-regulated modulator of apoptosis (PUMA)-related mitochondrial apoptotic signaling pathway; and stimulated the Trib3-mediated ER stress signaling pathway through the Akt-mTOR signaling axis. We also found that autophagy is an early response to Meth-induced stress upstream of apoptosis and plays a detrimental role in Meth-induced neuronal cell death. These results suggest that Meth exposure induces C/EBPβ expression, which plays an essential role in the neuronal apoptosis and autophagy induced by relatively high doses of Meth; however, relatively low concentrations of Meth did not change the expression of C/EBPβ in vitro. Further studies are needed to elucidate the role of C/EBPβ in low-dose Meth-induced neurotoxicity.-Xu, X., Huang, E., Luo, B., Cai, D., Zhao, X., Luo, Q., Jin, Y., Chen, L., Wang, Q

  14. Inflammation activates the interferon signaling pathways in taste bud cells.

    Science.gov (United States)

    Wang, Hong; Zhou, Minliang; Brand, Joseph; Huang, Liquan

    2007-10-03

    Patients with viral and bacterial infections or other inflammatory illnesses often experience taste dysfunctions. The agents responsible for these taste disorders are thought to be related to infection-induced inflammation, but the mechanisms are not known. As a first step in characterizing the possible role of inflammation in taste disorders, we report here evidence for the presence of interferon (IFN)-mediated signaling pathways in taste bud cells. IFN receptors, particularly the IFN-gamma receptor IFNGR1, are coexpressed with the taste cell-type markers neuronal cell adhesion molecule and alpha-gustducin, suggesting that both the taste receptor cells and synapse-forming cells in the taste bud can be stimulated by IFN. Incubation of taste bud-containing lingual epithelia with recombinant IFN-alpha and IFN-gamma triggered the IFN-mediated signaling cascades, resulting in the phosphorylation of the downstream STAT1 (signal transducer and activator of transcription protein 1) transcription factor. Intraperitoneal injection of lipopolysaccharide or polyinosinic:polycytidylic acid into mice, mimicking bacterial and viral infections, respectively, altered gene expression patterns in taste bud cells. Furthermore, the systemic administration of either IFN-alpha or IFN-gamma significantly increased the number of taste bud cells undergoing programmed cell death. These findings suggest that bacterial and viral infection-induced IFNs can act directly on taste bud cells, affecting their cellular function in taste transduction, and that IFN-induced apoptosis in taste buds may cause abnormal cell turnover and skew the representation of different taste bud cell types, leading to the development of taste disorders. To our knowledge, this is the first study providing direct evidence that inflammation can affect taste buds through cytokine signaling pathways.

  15. Autonomous rexinoid death signaling is suppressed by converging signaling pathways in immature leukemia cells.

    Science.gov (United States)

    Benoit, G R; Flexor, M; Besançon, F; Altucci, L; Rossin, A; Hillion, J; Balajthy, Z; Legres, L; Ségal-Bendirdjian, E; Gronemeyer, H; Lanotte, M

    2001-07-01

    On their own, retinoid X receptor (RXR)-selective ligands (rexinoids) are silent in retinoic acid receptor (RAR)-RXR heterodimers, and no selective rexinoid program has been described as yet in cellular systems. We report here on the rexinoid signaling capacity that triggers apoptosis of immature promyelocytic NB4 cells as a default pathway in the absence of survival factors. Rexinoid-induced apoptosis displays all features of bona fide programmed cell death and is inhibited by RXR, but not RAR antagonists. Several types of survival signals block rexinoid-induced apoptosis. RARalpha agonists switch the cellular response toward differentiation and induce the expression of antiapoptosis factors. Activation of the protein kinase A pathway in the presence of rexinoid agonists induces maturation and blocks immature cell apoptosis. Addition of nonretinoid serum factors also blocks cell death but does not induce cell differentiation. Rexinoid-induced apoptosis is linked to neither the presence nor stability of the promyelocytic leukemia-RARalpha fusion protein and operates also in non-acute promyelocytic leukemia cells. Together our results support a model according to which rexinoids activate in certain leukemia cells a default death pathway onto which several other signaling paradigms converge. This pathway is entirely distinct from that triggered by RAR agonists, which control cell maturation and postmaturation apoptosis.

  16. Kinetic modelling of in vitro data of PI3K, mTOR1, PTEN enzymes and on-target inhibitors Rapamycin, BEZ235, and LY294002.

    Science.gov (United States)

    Goltsov, Alexey; Tashkandi, Ghassan; Langdon, Simon P; Harrison, David J; Bown, James L

    2017-01-15

    The phosphatidylinositide 3-kinases (PI3K) and mammalian target of rapamycin-1 (mTOR1) are two key targets for anti-cancer therapy. Predicting the response of the PI3K/AKT/mTOR1 signalling pathway to targeted therapy is made difficult because of network complexities. Systems biology models can help explore those complexities but the value of such models is dependent on accurate parameterisation. Motivated by a need to increase accuracy in kinetic parameter estimation, and therefore the predictive power of the model, we present a framework to integrate kinetic data from enzyme assays into a unified enzyme kinetic model. We present exemplar kinetic models of PI3K and mTOR1, calibrated on in vitro enzyme data and founded on Michaelis-Menten (MM) approximation. We describe the effects of an allosteric mTOR1 inhibitor (Rapamycin) and ATP-competitive inhibitors (BEZ235 and LY294002) that show dual inhibition of mTOR1 and PI3K. We also model the kinetics of phosphatase and tensin homolog (PTEN), which modulates sensitivity of the PI3K/AKT/mTOR1 pathway to these drugs. Model validation with independent data sets allows investigation of enzyme function and drug dose dependencies in a wide range of experimental conditions. Modelling of the mTOR1 kinetics showed that Rapamycin has an IC 50 independent of ATP concentration and that it is a selective inhibitor of mTOR1 substrates S6K1 and 4EBP1: it retains 40% of mTOR1 activity relative to 4EBP1 phosphorylation and inhibits completely S6K1 activity. For the dual ATP-competitive inhibitors of mTOR1 and PI3K, LY294002 and BEZ235, we derived the dependence of the IC 50 on ATP concentration that allows prediction of the IC 50 at different ATP concentrations in enzyme and cellular assays. Comparison of drug effectiveness in enzyme and cellular assays showed that some features of these drugs arise from signalling modulation beyond the on-target action and MM approximation and require a systems-level consideration of the whole PI3K

  17. Curcumin mediates anticancer effects by modulating multiple cell signaling pathways.

    Science.gov (United States)

    Kunnumakkara, Ajaikumar B; Bordoloi, Devivasha; Harsha, Choudhary; Banik, Kishore; Gupta, Subash C; Aggarwal, Bharat B

    2017-08-01

    Curcumin, a component of a spice native to India, was first isolated in 1815 by Vogel and Pelletier from the rhizomes of Curcuma longa (turmeric) and, subsequently, the chemical structure of curcumin as diferuloylmethane was reported by Milobedzka et al. [(1910) 43., 2163-2170]. Since then, this polyphenol has been shown to exhibit antioxidant, anti-inflammatory, anticancer, antiviral, antibacterial, and antifungal activities. The current review primarily focuses on the anticancer potential of curcumin through the modulation of multiple cell signaling pathways. Curcumin modulates diverse transcription factors, inflammatory cytokines, enzymes, kinases, growth factors, receptors, and various other proteins with an affinity ranging from the pM to the mM range. Furthermore, curcumin effectively regulates tumor cell growth via modulation of numerous cell signaling pathways and potentiates the effect of chemotherapeutic agents and radiation against cancer. Curcumin can interact with most of the targets that are modulated by FDA-approved drugs for cancer therapy. The focus of this review is to discuss the molecular basis for the anticancer activities of curcumin based on preclinical and clinical findings. © 2017 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

  18. The chromatin remodeler SPLAYED regulates specific stress signaling pathways.

    Directory of Open Access Journals (Sweden)

    Justin W Walley

    2008-12-01

    Full Text Available Organisms are continuously exposed to a myriad of environmental stresses. Central to an organism's survival is the ability to mount a robust transcriptional response to the imposed stress. An emerging mechanism of transcriptional control involves dynamic changes in chromatin structure. Alterations in chromatin structure are brought about by a number of different mechanisms, including chromatin modifications, which covalently modify histone proteins; incorporation of histone variants; and chromatin remodeling, which utilizes ATP hydrolysis to alter histone-DNA contacts. While considerable insight into the mechanisms of chromatin remodeling has been gained, the biological role of chromatin remodeling complexes beyond their function as regulators of cellular differentiation and development has remained poorly understood. Here, we provide genetic, biochemical, and biological evidence for the critical role of chromatin remodeling in mediating plant defense against specific biotic stresses. We found that the Arabidopsis SWI/SNF class chromatin remodeling ATPase SPLAYED (SYD is required for the expression of selected genes downstream of the jasmonate (JA and ethylene (ET signaling pathways. SYD is also directly recruited to the promoters of several of these genes. Furthermore, we show that SYD is required for resistance against the necrotrophic pathogen Botrytis cinerea but not the biotrophic pathogen Pseudomonas syringae. These findings demonstrate not only that chromatin remodeling is required for selective pathogen resistance, but also that chromatin remodelers such as SYD can regulate specific pathways within biotic stress signaling networks.

  19. A SNP uncoupling Mina expression from the TGFβ signaling pathway.

    Science.gov (United States)

    Lian, Shang L; Mihi, Belgacem; Koyanagi, Madoka; Nakayama, Toshinori; Bix, Mark

    2018-03-01

    Mina is a JmjC family 2-oxoglutarate oxygenase with pleiotropic roles in cell proliferation, cancer, T cell differentiation, pulmonary inflammation, and intestinal parasite expulsion. Although Mina expression varies according to cell-type, developmental stage and activation state, its transcriptional regulation is poorly understood. Across inbred mouse strains, Mina protein level exhibits a bimodal distribution, correlating with inheritance of a biallelic haplotype block comprising 21 promoter/intron 1-region SNPs. We previously showed that heritable differences in Mina protein level are transcriptionally regulated. Accordingly, we decided to test the hypothesis that at least one of the promoter/intron 1-region SNPs perturbs a Mina cis-regulatory element (CRE). Here, we have comprehensively scanned for CREs across a Mina locus-spanning 26-kilobase genomic interval. We discovered 8 potential CREs and functionally validated 4 of these, the strongest of which (E2), residing in intron 1, contained a SNP whose BALB/c-but not C57Bl/6 allele-abolished both Smad3 binding and transforming growth factor beta (TGFβ) responsiveness. Our results demonstrate the TGFβ signaling pathway plays a critical role in regulating Mina expression and SNP rs4191790 controls heritable variation in Mina expression level, raising important questions regarding the evolution of an allele that uncouples Mina expression from the TGFβ signaling pathway. © 2017 The Authors. Immunity, Inflammation and Disease Published by John Wiley & Sons Ltd.

  20. Aberrant signaling pathways in medulloblastomas: a stem cell connection

    Directory of Open Access Journals (Sweden)

    Carolina Oliveira Rodini

    2010-12-01

    Full Text Available Medulloblastoma is a highly malignant primary tumor of the central nervous system. It represents the most frequent type of solid tumor and the leading cause of death related to cancer in early childhood. Current treatment includes surgery, chemotherapy and radiotherapy which may lead to severe cognitive impairment and secondary brain tumors. New perspectives for therapeutic development have emerged with the identification of stem-like cells displaying high tumorigenic potential and increased radio- and chemo-resistance in gliomas. Under the cancer stem cell hypothesis, transformation of neural stem cells and/or granular neuron progenitors of the cerebellum are though to be involved in medulloblastoma development. Dissecting the genetic and molecular alterations associated with this process should significantly impact both basic and applied cancer research. Based on cumulative evidences in the fields of genetics and molecular biology of medulloblastomas, we discuss the possible involvement of developmental signaling pathways as critical biochemical switches determining normal neurogenesis or tumorigenesis. From the clinical viewpoint, modulation of signaling pathways such as TGFβ, regulating neural stem cell proliferation and tumor development, might be attempted as an alternative strategy for future drug development aiming at more efficient therapies and improved clinical outcome of patients with pediatric brain cancers.

  1. Modulation of neurotrophic signaling pathways by polyphenols

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    Moosavi F

    2015-12-01

    Full Text Available Fatemeh Moosavi,1,2 Razieh Hosseini,1,2 Luciano Saso,3 Omidreza Firuzi1 1Medicinal and Natural Products Chemistry Research Center, Shiraz University of Medical Sciences, Shiraz, Iran; 2Department of Pharmacology, School of Veterinary Medicine, Shiraz University, Shiraz, Iran; 3Department of Physiology and Pharmacology “Vittorio Erspamer”, Sapienza University of Rome, Rome, Italy Abstract: Polyphenols are an important class of phytochemicals, and several lines of evidence have demonstrated their beneficial effects in the context of a number of pathologies including neurodegenerative disorders such as Alzheimer’s and Parkinson’s disease. In this report, we review the studies on the effects of polyphenols on neuronal survival, growth, proliferation and differentiation, and the signaling pathways involved in these neurotrophic actions. Several polyphenols including flavonoids such as baicalein, daidzein, luteolin, and nobiletin as well as nonflavonoid polyphenols such as auraptene, carnosic acid, curcuminoids, and hydroxycinnamic acid derivatives including caffeic acid phentyl ester enhance neuronal survival and promote neurite outgrowth in vitro, a hallmark of neuronal differentiation. Assessment of underlying mechanisms, especially in PC12 neuronal-like cells, reveals that direct agonistic effect on tropomyosin receptor kinase (Trk receptors, the main receptors of neurotrophic factors including nerve growth factor (NGF and brain-derived neurotrophic factor (BDNF explains the action of few polyphenols such as 7,8-dihydroxyflavone. However, several other polyphenolic compounds activate extracellular signal-regulated kinase (ERK and phosphoinositide 3-kinase (PI3K/Akt pathways. Increased expression of neurotrophic factors in vitro and in vivo is the mechanism of neurotrophic action of flavonoids such as scutellarin, daidzein, genistein, and fisetin, while compounds like apigenin and ferulic acid increase cyclic adenosine monophosphate

  2. Signaling Pathways Involved in Lunar Dust Induced Cytotoxicity

    Science.gov (United States)

    Zhang, Ye; Lam, Chiu-Wing; Scully, Robert R.; Williams, Kyle; Zalesak, Selina; Wu, Honglu; James, John T.

    2014-01-01

    The Moon's surface is covered by a layer of fine, reactive dust. Lunar dust contain about 1-2% of very fine dust (pathways involved in lunar dust-induced toxicity. F344 rats were exposed for 4 weeks (6h/d; 5d/wk) in nose-only inhalation chambers to concentrations of 0 (control air), 2.1, 6.1, 21, and 61 mg/m(exp 3) of lunar dust. Five rats per group were euthanized 1 day, 1 week, 1 month, and 3 months after the last inhalation exposure. The total RNAs were isolated from the blood or lung tissue after being lavaged, using the Qigen RNeasy kit. The Rat Fibrosis RT2 Profile PCR Array was used to profile the expression of 84 genes relevant to fibrosis. The genes with significant expression changes are identified and the gene expression data were further analyzed using IPA pathway analysis tool to determine the signaling pathways with significant changes.

  3. MicroRNA-gene signaling pathways in pancreatic cancer

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    Alexandra Drakaki

    2013-10-01

    Full Text Available Pancreatic cancer is the fourth most frequent cause of cancer-related deaths and is characterized by early metastasis and pronounced resistance to chemotherapy and radiation therapy. Despite extensive esearch efforts, there is not any substantial progress regarding the identification of novel drugs against pancreatic cancer. Although the introduction of the chemotherapeutic agent gemcitabine improved clinical response, the prognosis of these patients remained extremely poor with a 5-year survival rate of 3-5%. Thus, the identification of the novel molecular pathways involved in pancreatic oncogenesis and the development of new and potent therapeutic options are highly desirable. Here, we describe how microRNAs control signaling pathways that are frequently deregulated during pancreatic oncogenesis. In addition, we provide evidence that microRNAs could be potentially used as novel pancreatic cancer therapeutics through reversal of chemotherapy and radiotherapy resistance or regulation of essential molecular pathways. Further studies should integrate the deregulated genes and microRNAs into molecular networks in order to identify the central regulators of pancreatic oncogenesis. Targeting these central regulators could lead to the development of novel targeted therapeutic approaches for pancreatic cancer patients.

  4. Signaling Pathways Regulating Redox Balance in Cancer Metabolism.

    Science.gov (United States)

    De Santis, Maria Chiara; Porporato, Paolo Ettore; Martini, Miriam; Morandi, Andrea

    2018-01-01

    The interplay between rewiring tumor metabolism and oncogenic driver mutations is only beginning to be appreciated. Metabolic deregulation has been described for decades as a bystander effect of genomic aberrations. However, for the biology of malignant cells, metabolic reprogramming is essential to tackle a harsh environment, including nutrient deprivation, reactive oxygen species production, and oxygen withdrawal. Besides the well-investigated glycolytic metabolism, it is emerging that several other metabolic fluxes are relevant for tumorigenesis in supporting redox balance, most notably pentose phosphate pathway, folate, and mitochondrial metabolism. The relationship between metabolic rewiring and mutant genes is still unclear and, therefore, we will discuss how metabolic needs and oncogene mutations influence each other to satisfy cancer cells' demands. Mutations in oncogenes, i.e., PI3K/AKT/mTOR, RAS pathway, and MYC, and tumor suppressors, i.e., p53 and liver kinase B1, result in metabolic flexibility and may influence response to therapy. Since metabolic rewiring is shaped by oncogenic driver mutations, understanding how specific alterations in signaling pathways affect different metabolic fluxes will be instrumental for the development of novel targeted therapies. In the era of personalized medicine, the combination of driver mutations, metabolite levels, and tissue of origins will pave the way to innovative therapeutic interventions.

  5. MiRNA-199a-3p Regulates C2C12 Myoblast Differentiation through IGF-1/AKT/mTOR Signal Pathway

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    Long Jia

    2013-12-01

    Full Text Available MicroRNAs constitute a class of ~22-nucleotide non-coding RNAs. They modulate gene expression by associating with the 3' untranslated regions (3' UTRs of messenger RNAs (mRNAs. Although multiple miRNAs are known to be regulated during myoblast differentiation, their individual roles in muscle development are still not fully understood. In this study, we showed that miR-199a-3p was highly expressed in skeletal muscle and was induced during C2C12 myoblasts differentiation. We also identified and confirmed several genes of the IGF-1/AKT/mTOR signal pathway, including IGF-1, mTOR, and RPS6KA6, as important cellular targets of miR-199a-3p in myoblasts. Overexpression of miR-199a-3p partially blocked C2C12 myoblast differentiation and the activation of AKT/mTOR signal pathway, while interference of miR-199a-3p by antisense oligonucleotides promoted C2C12 differentiation and myotube hypertrophy. Thus, our studies have established miR-199a-3p as a potential regulator of myogenesis through the suppression of IGF-1/AKT/mTOR signal pathway.

  6. Targeting mTOR in HIV-Negative Classic Kaposi's Sarcoma

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    Ofer Merimsky

    2008-01-01

    Full Text Available A 66-year old female with HIV-negative classic Kaposi's sarcoma responded to mTOR targeting by rapamycin. The response was well documented by PET-CT. This case provides supporting evidence that the mTOR pathway may be important in the tumorigenesis of KS and that rapamycin may have activity in this disease.

  7. Combination of mTOR and MAPK Inhibitors—A Potential Way to Treat Renal Cell Carcinoma

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    Ashutosh Chauhan

    2016-10-01

    Full Text Available Renal cell carcinoma (RCC is the most common neoplasm that occurs in the kidney and is marked by a unique biology, with a long history of poor response to conventional cancer treatments. In the past few years, there have been significant advancements to understand the biology of RCC. This has led to the introduction of novel targeted therapies in the management of patients with metastatic disease. Patients treated with targeted therapies for RCC had shown positive impact on overall survival, however, no cure is possible and patients need to undergo treatment for long periods of time, which raises challenges to manage the associated adverse events. Moreover, many patients may not respond to it and even response may not last long enough in the responders. Many inhibitors of the Mammalian target of Rapamycin (mTOR signaling pathway are currently being used in treatment of advanced RCC. Studies showed that inhibitions of mTOR pathways induce Mitogen-Activated Protein Kinase (MAPK escape cell death and cells become resistant to mTOR inhibitors. Because of this, there is a need to inhibit both pathways with their inhibitors comparatively for a better outcome and treatment of patients with RCC.

  8. An algorithm for modularization of MAPK and calcium signaling pathways: comparative analysis among different species.

    Science.gov (United States)

    Nayak, Losiana; De, Rajat K

    2007-12-01

    Signaling pathways are large complex biochemical networks. It is difficult to analyze the underlying mechanism of such networks as a whole. In the present article, we have proposed an algorithm for modularization of signal transduction pathways. Unlike studying a signaling pathway as a whole, this enables one to study the individual modules (less complex smaller units) easily and hence to study the entire pathway better. A comparative study of modules belonging to different species (for the same signaling pathway) has been made, which gives an overall idea about development of the signaling pathways over the taken set of species of calcium and MAPK signaling pathways. The superior performance, in terms of biological significance, of the proposed algorithm over an existing community finding algorithm of Newman [Newman MEJ. Modularity and community structure in networks. Proc Natl Acad Sci USA 2006;103(23):8577-82] has been demonstrated using the aforesaid pathways of H. sapiens.

  9. PSFC: a Pathway Signal Flow Calculator App for Cytoscape [version 2; referees: 2 approved

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    Lilit Nersisyan

    2017-04-01

    Full Text Available Cell signaling pathways are sequences of biochemical reactions that propagate an input signal, such as a hormone binding to a cell-surface receptor, into the cell to trigger a reactive process. Assessment of pathway activities is crucial for determining which pathways play roles in disease versus normal conditions. To date various pathway flow/perturbation assessment tools are available, however they are constrained to specific algorithms and specific data types. There are no accepted standards for evaluation of pathway activities or simulation of flow propagation events in pathways, and the results of different software are difficult to compare. Here we present Pathway Signal Flow Calculator (PSFC, a Cytoscape app for calculation of a pathway signal flow based on the pathway topology and node input data. The app provides a rich framework for customization of different signal flow algorithms to allow users to apply various approaches within a single computational framework.

  10. Activation of the Akt/mTOR signaling pathway: A potential response to long-term neuronal loss in the hippocampus after sepsis

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    Jia-nan Guo

    2017-01-01

    Full Text Available Survivors of sepsis may suffer chronic cognitive impairment as a long-term sequela. However, the precise mechanisms of cognitive dysfunction after sepsis are not well understood. We employed the cecal ligation-and-puncture-induced septic mouse model. We observed elevated phosphorylation of Akt, mammalian target of rapamycin (mTOR and p70S6K on days 14 and 60, progressive neuronal loss in the cornu ammonis 1 region, and abnormal neuronal morphology in the hippocampus in the sepsis mouse model. These findings indicate that changes in neuronal morphology and number in the hippocampus after sepsis were associated with strong activation of the Akt/mTOR signaling pathway, and may reflect a “self-rescuing” feedback response to neuronal loss after sepsis.

  11. Yeast signaling pathways in the oxidative stress response

    Energy Technology Data Exchange (ETDEWEB)

    Ikner, Aminah [Section of Microbiology, Division of Biological Sciences, University of California, Davis, CA 95616 (United States); Shiozaki, Kazuhiro [Section of Microbiology, Division of Biological Sciences, University of California, Davis, CA 95616 (United States)]. E-mail: kshiozaki@ucdavis.edu

    2005-01-06

    Oxidative stress that generates the reactive oxygen species (ROS) is one of the major causes of DNA damage and mutations. The 'DNA damage checkpoint' that arrests cell cycle and repairs damaged DNA has been a focus of recent studies, and the genetically amenable model systems provided by yeasts have been playing a leading role in the eukaryotic checkpoint research. However, means to eliminate ROS are likely to be as important as the DNA repair mechanisms in order to suppress mutations in the chromosomal DNA, and yeasts also serve as excellent models to understand how eukaryotes combat oxidative stress. In this article, we present an overview of the signaling pathways that sense oxidative stress and induce expression of various anti-oxidant genes in the budding yeast Saccharomyces cerevisiae, the fission yeast Schizosaccharomyces pombe and the pathogenic yeast Candida albicans. Three conserved signaling modules have been identified in the oxidative stress response of these diverse yeast species: the stress-responsive MAP kinase cascade, the multistep phosphorelay and the AP-1-like transcription factor. The structure and function of these signaling modules are discussed.

  12. Yeast signaling pathways in the oxidative stress response

    International Nuclear Information System (INIS)

    Ikner, Aminah; Shiozaki, Kazuhiro

    2005-01-01

    Oxidative stress that generates the reactive oxygen species (ROS) is one of the major causes of DNA damage and mutations. The 'DNA damage checkpoint' that arrests cell cycle and repairs damaged DNA has been a focus of recent studies, and the genetically amenable model systems provided by yeasts have been playing a leading role in the eukaryotic checkpoint research. However, means to eliminate ROS are likely to be as important as the DNA repair mechanisms in order to suppress mutations in the chromosomal DNA, and yeasts also serve as excellent models to understand how eukaryotes combat oxidative stress. In this article, we present an overview of the signaling pathways that sense oxidative stress and induce expression of various anti-oxidant genes in the budding yeast Saccharomyces cerevisiae, the fission yeast Schizosaccharomyces pombe and the pathogenic yeast Candida albicans. Three conserved signaling modules have been identified in the oxidative stress response of these diverse yeast species: the stress-responsive MAP kinase cascade, the multistep phosphorelay and the AP-1-like transcription factor. The structure and function of these signaling modules are discussed

  13. Ghrelin promotes human non-small cell lung cancer A549 cell proliferation through PI3K/Akt/mTOR/P70S6K and ERK signaling pathways.

    Science.gov (United States)

    Zhu, Jianhua; Yao, Jianfeng; Huang, Rongfu; Wang, Yueqin; Jia, Min; Huang, Yan

    2018-04-06

    Ghrelin is a gastric acyl-peptide that plays an important role in cell proliferation. In the present study, we explored the role of ghrelin in A549 cell proliferation and the possible molecular mechanisms. We found that ghrelin promotes A549 cell proliferation, knockdown of the growth hormone secretagogue receptor (GHSR) attenuated A549 cell proliferation caused by ghrelin. Ghrelin induced the rapid phosphorylation of phosphatidylinositol 3-kinase (PI3K), Akt, ERK, mammalian target of rapamycin (mTOR) and P70S6K. PI3K inhibitor (LY 294002), ERK inhibitor (PD98059) and mTOR inhibitor (Rapamycin) inhibited ghrelin-induced A549 cell proliferation. Moreover, GHSR siRNA inhibited phosphorylation of PI3K, Akt, ERK, mTOR and P70S6K induced by ghrelin. Akt and mTOR/P70S6K phosphorylation was inhibited by LY 294002 but not by PD98059. These results indicate that ghrelin promotes A549 cell proliferation via GHSR-dependent PI3K/Akt/mTOR/P70S6K and ERK signaling pathways. Copyright © 2018 Elsevier Inc. All rights reserved.

  14. Curcumin inhibited HGF-induced EMT and angiogenesis through regulating c-Met dependent PI3K/Akt/mTOR signaling pathways in lung cancer

    Directory of Open Access Journals (Sweden)

    Demin Jiao

    2016-01-01

    Full Text Available The epithelial-mesenchymal transition (EMT and angiogenesis have emerged as two pivotal events in cancer progression. Curcumin has been extensively studied in preclinical models and clinical trials of cancer prevention due to its favorable toxicity profile. However, the possible involvement of curcumin in the EMT and angiogenesis in lung cancer remains unclear. This study found that curcumin inhibited hepatocyte growth factor (HGF-induced migration and EMT-related morphological changes in A549 and PC-9 cells. Moreover, pretreatment with curcumin blocked HGF-induced c-Met phosphorylation and downstream activation of Akt, mTOR, and S6. These effects mimicked that of c-Met inhibitor SU11274 or PI3 kinase inhibitor LY294002 or mTOR inhibitor rapamycin treatment. c-Met gene overexpression analysis further demonstrated that curcumin suppressed lung cancer cell EMT by inhibiting c-Met/Akt/mTOR signaling pathways. In human umbilical vein endothelial cells (HUVECs, we found that curcumin also significantly inhibited PI3K/Akt/mTOR signaling and induced apoptosis and reduced migration and tube formation of HGF-treated HUVEC. Finally, in the experimental mouse model, we showed that curcumin inhibited HGF-stimulated tumor growth and induced an increase in E-cadherin expression and a decrease in vimentin, CD34, and vascular endothelial growth factor (VEGF expression. Collectively, these findings indicated that curcumin could inhibit HGF-promoted EMT and angiogenesis by targeting c-Met and blocking PI3K/Akt/mTOR pathways.

  15. Involvement of PI3K/Akt Signaling Pathway and Its Downstream Intracellular Targets in the Antidepressant-Like Effect of Creatine.

    Science.gov (United States)

    Cunha, Mauricio P; Budni, Josiane; Ludka, Fabiana K; Pazini, Francis L; Rosa, Julia Macedo; Oliveira, Ágatha; Lopes, Mark W; Tasca, Carla I; Leal, Rodrigo B; Rodrigues, Ana Lúcia S

    2016-07-01

    Creatine has been proposed to exert beneficial effects in the management of depression, but the cell signaling pathways implicated in its antidepressant effects are not well established. This study investigated the involvement of PI3K/Akt signaling pathway and its downstream intracellular targets in the antidepressant-like effect of creatine. The acute treatment of mice with creatine (1 mg/kg, po) increased the Akt and P70S6K phosphorylation, and HO-1, GPx and PSD95 immunocontents. The pretreatment of mice with LY294002 (10 nmol/mouse, icv, PI3K inhibitor), wortmannin (0.1 μg/mouse, icv, PI3K inhibitor), ZnPP (10 μg/mouse, icv, HO-1 inhibitor), or rapamycin (0.2 nmol/mouse, icv, mTOR inhibitor) prevented the antidepressant-like effect of creatine (1 mg/kg, po) in the TST. In addition, the administration of subeffective dose of either the selective GSK3 inhibitor AR-A014418 (0.01 μg/mouse, icv), the nonselective GSK3 inhibitor lithium chloride (10 mg/kg, po), or the HO-1 inductor CoPP (0.01 μg/mouse, icv), in combination with a subeffective dose of creatine (0.01 mg/kg, po) reduced the immobility time in the TST as compared with either drug alone. No treatment caused significant changes in the locomotor activity of mice. These results indicate that the antidepressant-like effect of creatine in the TST depends on the activation of Akt, Nrf2/HO-1, GPx, and mTOR, and GSK3 inhibition.

  16. Germline and somatic mutations in the MTOR gene in focal cortical dysplasia and epilepsy

    DEFF Research Database (Denmark)

    Møller, Rikke S; Weckhuysen, Sarah; Chipaux, Mathilde

    2016-01-01

    OBJECTIVE: To assess the prevalence of somatic MTOR mutations in focal cortical dysplasia (FCD) and of germline MTOR mutations in a broad range of epilepsies. METHODS: We collected 20 blood-brain paired samples from patients with FCD and searched for somatic variants using deep-targeted gene panel...... sequencing. Germline mutations in MTOR were assessed in a French research cohort of 93 probands with focal epilepsies and in a diagnostic Danish cohort of 245 patients with a broad range of epilepsies. Data sharing among collaborators allowed us to ascertain additional germline variants in MTOR. RESULTS: We...... detected recurrent somatic variants (p.Ser2215Phe, p.Ser2215Tyr, and p.Leu1460Pro) in the MTOR gene in 37% of participants with FCD II and showed histologic evidence for activation of the mTORC1 signaling cascade in brain tissue. We further identified 5 novel de novo germline missense MTOR variants in 6...

  17. Paris saponin-induced autophagy promotes breast cancer cell apoptosis via the Akt/mTOR signaling pathway.

    Science.gov (United States)

    Xie, Zhan-Zhi; Li, Man-Mei; Deng, Peng-Fei; Wang, Sheng; Wang, Lei; Lu, Xue-Ping; Hu, Liu-Bing; Chen, Zui; Jie, Hui-Yang; Wang, Yi-Fei; Liu, Xiao-Xiao; Liu, Zhong

    2017-02-25

    Paris saponins possess anticancer, anti-inflammatory, and antiviral effects. However, the anticancer effect of Paris saponins has not been well elucidated and the mechanisms underlying the potential function of Paris saponins in cancer therapy are needed to be further identify. In this study, we report that saponin compounds isolated from Paris polyphylla exhibited antitumor activity against breast cancer cell lines, MCF-7 and MDA-MB-231. Paris saponin XA-2 induced apoptosis in both cell lines, as evidenced by the activation of caspases and cleavage of Poly (ADP-ribose) polymerase. The ability of XA-2 to induce autophagy was confirmed by acridine orange staining, accumulation of autophagosome-bound Long chain 3 (LC3)-II, and measurement of autophagic flux. XA-2-induced autophagy was observed to promote apoptosis by the combined treatment of breast cancer cell lines with XA-2 and autophagy inhibitors 3-methyladenine and bafilomycin A1, respectively. Moreover, we report a decrease in the levels of Akt/mTOR signaling pathway proteins, such as the phosphorylated forms of Akt, mTOR, P70S6K, and eukaryotic translation initiation factor 4E-binding protein 1 (4EBP1). Taken together, these results provide important insights explaining the anticancer activity of Paris saponins and the potential development of XA-2 as a new therapeutic agent. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. In vitro reconstitution of an abscisic acid signalling pathway

    KAUST Repository

    Fujii, Hiroaki; Chinnusamy, Viswanathan; Rodrigues, Americo; Rubio, Silvia; Antoni, Regina; Park, Sang-Youl; Cutler, Sean R.; Sheen, Jen; Rodriguez, Pedro L.; Zhu, Jian-Kang

    2009-01-01

    The phytohormone abscisic acid (ABA) regulates the expression of many genes in plants; it has critical functions in stress resistance and in growth and development. Several proteins have been reported to function as ABA receptors, and many more are known to be involved in ABA signalling. However, the identities of ABA receptors remain controversial and the mechanism of signalling from perception to downstream gene expression is unclear. Here we show that by combining the recently identified ABA receptor PYR1 with the type 2C protein phosphatase (PP2C) ABI1, the serine/threonine protein kinase SnRK2.6/OST1 and the transcription factor ABF2/AREB1, we can reconstitute ABA-triggered phosphorylation of the transcription factor in vitro. Introduction of these four components into plant protoplasts results in ABA-responsive gene expression. Protoplast and test-tube reconstitution assays were used to test the function of various members of the receptor, protein phosphatase and kinase families. Our results suggest that the default state of the SnRK2 kinases is an autophosphorylated, active state and that the SnRK2 kinases are kept inactive by the PP2Cs through physical interaction and dephosphorylation. We found that in the presence of ABA, the PYR/PYL (pyrabactin resistance 1/PYR1-like) receptor proteins can disrupt the interaction between the SnRK2s and PP2Cs, thus preventing the PP2C-mediated dephosphorylation of the SnRK2s and resulting in the activation of the SnRK2 kinases. Our results reveal new insights into ABA signalling mechanisms and define a minimal set of core components of a complete major ABA signalling pathway. © 2009 Macmillan Publishers Limited. All rights reserved.

  19. In vitro reconstitution of an abscisic acid signalling pathway

    KAUST Repository

    Fujii, Hiroaki

    2009-11-18

    The phytohormone abscisic acid (ABA) regulates the expression of many genes in plants; it has critical functions in stress resistance and in growth and development. Several proteins have been reported to function as ABA receptors, and many more are known to be involved in ABA signalling. However, the identities of ABA receptors remain controversial and the mechanism of signalling from perception to downstream gene expression is unclear. Here we show that by combining the recently identified ABA receptor PYR1 with the type 2C protein phosphatase (PP2C) ABI1, the serine/threonine protein kinase SnRK2.6/OST1 and the transcription factor ABF2/AREB1, we can reconstitute ABA-triggered phosphorylation of the transcription factor in vitro. Introduction of these four components into plant protoplasts results in ABA-responsive gene expression. Protoplast and test-tube reconstitution assays were used to test the function of various members of the receptor, protein phosphatase and kinase families. Our results suggest that the default state of the SnRK2 kinases is an autophosphorylated, active state and that the SnRK2 kinases are kept inactive by the PP2Cs through physical interaction and dephosphorylation. We found that in the presence of ABA, the PYR/PYL (pyrabactin resistance 1/PYR1-like) receptor proteins can disrupt the interaction between the SnRK2s and PP2Cs, thus preventing the PP2C-mediated dephosphorylation of the SnRK2s and resulting in the activation of the SnRK2 kinases. Our results reveal new insights into ABA signalling mechanisms and define a minimal set of core components of a complete major ABA signalling pathway. © 2009 Macmillan Publishers Limited. All rights reserved.

  20. Interconnection between thyroid hormone signalling pathways and parvovirus cytotoxic functions.

    Science.gov (United States)

    Vanacker, J M; Laudet, V; Adelmant, G; Stéhelin, D; Rommelaere, J

    1993-01-01

    Nonstructural (NS) proteins of autonomous parvoviruses can repress expression driven by heterologous promoters, an activity which thus far has not been separated from their cytotoxic effects. It is shown here that, in transient transfection assays, the NS-1 protein of the parvovirus minute virus of mice (MVMp) activates the promoter of the human c-erbA1 gene, encoding the thyroid hormone (T3) receptor alpha. The endogenous c-erbA1 promoter is also a target for induction upon MVMp infection. Moreover, T3 was found to up-modulate the level of cell sensitivity to parvovirus attack. These data suggest an interconnection between T3 signalling and NS cytotoxic pathways. Images PMID:8230488

  1. Use of glycolytic pathways for inhibiting or measuring oncogenic signaling

    Science.gov (United States)

    Onodera, Yasuhito; Bissell, Mina

    2017-06-27

    Disclosed are methods in which glucose metabolism is correlated to oncogenesis through certain specific pathways; inhibition of certain enzymes is shown to interfere with oncogenic signaling, and measurement of certain enzyme levels is correlated with patient survival. The present methods comprise measuring level of expression of at least one of the enzymes involved in glucose uptake or metabolism, wherein increased expression of the at least one of the enzymes relative to expression in a normal cell correlates with poor prognosis of disease in a patient. Preferably the genes whose expression level is measured include GLUT3, PFKP, GAPDH, ALDOC, LDHA and GFPT2. Also disclosed are embodiments directed towards downregulating the expression of some genes in glucose uptake and metabolism.

  2. Current Views of Toll-Like Receptor Signaling Pathways

    Directory of Open Access Journals (Sweden)

    Masahiro Yamamoto

    2010-01-01

    Full Text Available On microbial invasion, the host immediately evokes innate immune responses. Recent studies have demonstrated that Toll-like receptors (TLRs play crucial roles in innate responses that lead not only to the clearance of pathogens but also to the efficient establishment of acquired immunity by directly detecting molecules from microbes. In terms of intracellular TLR-mediated signaling pathways, cytoplasmic adaptor molecules containing Toll/IL-1R (TIR domains play important roles in inflammatory immune responses through the production of proinflammatory cytokines, nitric oxide, and type I interferon, and upregulation of costimulatory molecules. In this paper, we will describe our current understanding of the relationship between TLRs and their ligands derived from pathogens such as viruses, bacteria, fungi, and parasites. Moreover, we will review the historical and current literature to describe the mechanisms behind TLR-mediated activation of innate immune responses.

  3. Signal transduction in mitogenesis: Further evidence for multiple pathways

    International Nuclear Information System (INIS)

    Rozengurt, E.; Erusalimsky, J.; Mehmet, H.; Morris, C.; Nanberg, E.; Sinnett-Smith, J.

    1988-01-01

    Growth factors are implicated in a wide variety of physiological and pathological processes, including embryogenesis, hematopoiesis, would healing, immune responses, atherosclerosis, and neoplasia. An important link between growth factors and their receptors and oncogene products has also been established. Thus, the elucidation of the mechanism of action of growth factors has emerged as one of the fundamental problems in biology and may prove crucial for understanding the unrestrained proliferation of cancer cells. A new and intriguing development is the discovery that neuropeptides localized in neural and neuroendocrine cells of mammalian tissue can also act as growth factors for cells in culture. Furthermore, indirect evidence is accumulating that the mitogenic effects of neuropeptides may be relevant for a variety of long-term biological processes, including development and oncogenesis. In this context, the peptides of the bombesin family are of particular significance. These peptides are potent mitogens for Swiss 3T3 cells and may act as autocrine growth factors for small cell lung cancer. Here, the authors summarize their recent studies using bombesin-like peptides for elucidating the signal transduction pathways leading to mitogenesis and compare these pathways with those elicited by other growth factors

  4. Analysis list: Mtor [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Mtor + mm9 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/target/Mtor.1.tsv http://dbarchive.bioscience...dbc.jp/kyushu-u/mm9/target/Mtor.5.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/tar...get/Mtor.10.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/colo/Mtor..tsv http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/colo/.gml ...

  5. The Spectrin cytoskeleton regulates the Hippo signalling pathway.

    Science.gov (United States)

    Fletcher, Georgina C; Elbediwy, Ahmed; Khanal, Ichha; Ribeiro, Paulo S; Tapon, Nic; Thompson, Barry J

    2015-04-01

    The Spectrin cytoskeleton is known to be polarised in epithelial cells, yet its role remains poorly understood. Here, we show that the Spectrin cytoskeleton controls Hippo signalling. In the developing Drosophila wing and eye, loss of apical Spectrins (alpha/beta-heavy dimers) produces tissue overgrowth and mis-regulation of Hippo target genes, similar to loss of Crumbs (Crb) or the FERM-domain protein Expanded (Ex). Apical beta-heavy Spectrin binds to Ex and co-localises with it at the apical membrane to antagonise Yki activity. Interestingly, in both the ovarian follicular epithelium and intestinal epithelium of Drosophila, apical Spectrins and Crb are dispensable for repression of Yki, while basolateral Spectrins (alpha/beta dimers) are essential. Finally, the Spectrin cytoskeleton is required to regulate the localisation of the Hippo pathway effector YAP in response to cell density human epithelial cells. Our findings identify both apical and basolateral Spectrins as regulators of Hippo signalling and suggest Spectrins as potential mechanosensors. © 2015 The Authors. Published under the terms of the CC BY 4.0 license.

  6. The Transcriptional Landscape of p53 Signalling Pathway

    Directory of Open Access Journals (Sweden)

    Chizu Tanikawa

    2017-06-01

    Full Text Available Although recent cancer genomics studies have identified a large number of genes that were mutated in human cancers, p53 remains as the most frequently mutated gene. To further elucidate the p53-signalling network, we performed transcriptome analysis on 24 tissues in p53+/+ or p53−/− mice after whole-body X-ray irradiation. Here we found transactivation of a total of 3551 genes in one or more of the 24 tissues only in p53+/+ mice, while 2576 genes were downregulated. p53 mRNA expression level in each tissue was significantly associated with the number of genes upregulated by irradiation. Annotation using TCGA (The Cancer Genome Atlas database revealed that p53 negatively regulated mRNA expression of several cancer therapeutic targets or pathways such as BTK, SYK, and CTLA4 in breast cancer tissues. In addition, stomach exhibited the induction of Krt6, Krt16, and Krt17 as well as loricrin, an epidermal differentiation marker, after the X-ray irradiation only in p53+/+ mice, implying a mechanism to protect damaged tissues by rapid induction of differentiation. Our comprehensive transcriptome analysis elucidated tissue specific roles of p53 and its signalling networks in DNA-damage response that will enhance our understanding of cancer biology.

  7. RNA Sequencing Identifies Upregulated Kyphoscoliosis Peptidase and Phosphatidic Acid Signaling Pathways in Muscle Hypertrophy Generated by Transgenic Expression of Myostatin Propeptide

    Directory of Open Access Journals (Sweden)

    Yuanxin Miao

    2015-04-01

    Full Text Available Myostatin (MSTN, a member of the transforming growth factor-β superfamily, plays a crucial negative role in muscle growth. MSTN mutations or inhibitions can dramatically increase muscle mass in most mammal species. Previously, we generated a transgenic mouse model of muscle hypertrophy via the transgenic expression of the MSTN N-terminal propeptide cDNA under the control of the skeletal muscle-specific MLC1 promoter. Here, we compare the mRNA profiles between transgenic mice and wild-type littermate controls with a high-throughput RNA sequencing method. The results show that 132 genes were significantly differentially expressed between transgenic mice and wild-type control mice; 97 of these genes were up-regulated, and 35 genes were down-regulated in the skeletal muscle. Several genes that had not been reported to be involved in muscle hypertrophy were identified, including up-regulated myosin binding protein H (mybph, and zinc metallopeptidase STE24 (Zmpste24. In addition, kyphoscoliosis peptidase (Ky, which plays a vital role in muscle growth, was also up-regulated in the transgenic mice. Interestingly, a pathway analysis based on grouping the differentially expressed genes uncovered that cardiomyopathy-related pathways and phosphatidic acid (PA pathways (Dgki, Dgkz, Plcd4 were up-regulated. Increased PA signaling may increase mTOR signaling, resulting in skeletal muscle growth. The findings of the RNA sequencing analysis help to understand the molecular mechanisms of muscle hypertrophy caused by MSTN inhibition.

  8. RNA sequencing identifies upregulated kyphoscoliosis peptidase and phosphatidic acid signaling pathways in muscle hypertrophy generated by transgenic expression of myostatin propeptide.

    Science.gov (United States)

    Miao, Yuanxin; Yang, Jinzeng; Xu, Zhong; Jing, Lu; Zhao, Shuhong; Li, Xinyun

    2015-04-09

    Myostatin (MSTN), a member of the transforming growth factor-β superfamily, plays a crucial negative role in muscle growth. MSTN mutations or inhibitions can dramatically increase muscle mass in most mammal species. Previously, we generated a transgenic mouse model of muscle hypertrophy via the transgenic expression of the MSTN N-terminal propeptide cDNA under the control of the skeletal muscle-specific MLC1 promoter. Here, we compare the mRNA profiles between transgenic mice and wild-type littermate controls with a high-throughput RNA sequencing method. The results show that 132 genes were significantly differentially expressed between transgenic mice and wild-type control mice; 97 of these genes were up-regulated, and 35 genes were down-regulated in the skeletal muscle. Several genes that had not been reported to be involved in muscle hypertrophy were identified, including up-regulated myosin binding protein H (mybph), and zinc metallopeptidase STE24 (Zmpste24). In addition, kyphoscoliosis peptidase (Ky), which plays a vital role in muscle growth, was also up-regulated in the transgenic mice. Interestingly, a pathway analysis based on grouping the differentially expressed genes uncovered that cardiomyopathy-related pathways and phosphatidic acid (PA) pathways (Dgki, Dgkz, Plcd4) were up-regulated. Increased PA signaling may increase mTOR signaling, resulting in skeletal muscle growth. The findings of the RNA sequencing analysis help to understand the molecular mechanisms of muscle hypertrophy caused by MSTN inhibition.

  9. Tofacitinib Represses the Janus Kinase-Signal Transducer and Activators of Transcription Signalling Pathway in Keratinocytes.

    Science.gov (United States)

    Srivastava, Ankit; Ståhle, Mona; Pivarcsi, Andor; Sonkoly, Enikö

    2018-05-08

    Tofacitinib is a Janus kinase (JAK) inhibitor, which has shown efficacy in treating psoriasis. The mode of action of tofacitinib is not completely understood but it has been thought to be mediated by the inhibition of CD4+ T-cell activation. Here, we investigated whether the molecular targets of tofacitinib are expressed in keratinocytes, and whether tofacitinib can modulate the activity of the JAK/Signal Transducer and Activators of Transcription (STAT)-pathway in keratinocytes. Transcriptomic profiling of human keratinocytes treated with IL-22 in combination with tofacitinib revealed that tofacitinib could prevent the majority of IL-22-mediated gene expression changes. Pathway analysis of tofacitinib-regulated genes in keratinocytes revealed enrichment of genes involved in the JAK/STAT signalling pathway. Quantitative real-time-PCR confirmed the upregulation of S100A7 and downregulation of EGR1 expression by IL-22, which was prevented by tofacitinib pre-treatment. These results indicate a direct effect of tofacinitib on keratinocytes, which can have relevance for systemic as well as for topical treatment of psoriasis with tofacitinib.

  10. Ames dwarf (Prop1(df)/Prop1(df)) mice display increased sensitivity of the major GH-signaling pathways in liver and skeletal muscle.

    Science.gov (United States)

    Miquet, Johanna G; Muñoz, Marina C; Giani, Jorge F; González, Lorena; Dominici, Fernando P; Bartke, Andrzej; Turyn, Daniel; Sotelo, Ana I

    2010-04-01

    Growth hormone (GH) is an anabolic hormone that regulates growth and metabolism. Ames dwarf mice are natural mutants for Prop1, with impaired development of anterior pituitary and undetectable levels of circulating GH, prolactin and TSH. They constitute an endocrine model of life-long GH-deficiency. The main signaling cascades activated by GH binding to its receptor are the JAK2/STATs, PI-3K/Akt and the MAPK Erk1/2 pathways. We have previously reported that GH-induced STAT5 activation was higher in Ames dwarf mice liver compared to non-dwarf controls. The aim of this study was to evaluate the principal components of the main GH-signaling pathways under GH-deficiency in liver and skeletal muscle, another GH-target tissue. Ames dwarf mice and their non-dwarf siblings were assessed. Animals were injected i.p. with GH or saline 15min before tissue removal. Protein content and phosphorylation of signaling mediators were determined by immunoblotting of tissue solubilizates. GH was able to induce STAT5 and STAT3 tyrosine phosphorylation in both liver and muscle, but the response was higher for Ames dwarf mice than for non-dwarf controls. When Erk1/2 activation was assessed in liver, only dwarf mice showed GH-induced phosphorylation, while in muscle no response to the hormone was found in either genotype. GH-induced Akt phosphorylation at Ser473 in liver was only detected in dwarf mice. In skeletal muscle, both normal and dwarf mice responded to a GH stimulus, although dwarf mice presented higher GH activation levels. The phosphorylation of GSK-3, a substrate of Akt, increased upon hormone stimulation only in dwarf mice in both tissues. In contrast, no differences in the phosphorylation of mTOR, another substrate of Akt, were observed after GH stimulus, either in normal or dwarf mice in liver, while we were unable to determine mTOR in muscle. Protein content of GH-receptor and of the signaling mediators studied did not vary between normal and dwarf animals in the assessed

  11. Systems Biomedicine of Rabies Delineates the Affected Signaling pathways

    Directory of Open Access Journals (Sweden)

    Sayed Hamid Reza Mozhgani

    2016-11-01

    Full Text Available The prototypical neurotropic virus, rabies, is a member of the Rhabdoviridae family that causes lethal encephalomyelitis. Although there have been a plethora of studies investigating the etiological mechanism of the rabies virus and many precautionary methods have been implemented to avert the disease outbreak over the last century, the disease has surprisingly no definite remedy at its late stages. The psychological symptoms and the underlying etiology, as well as the rare survival rate from rabies encephalitis, has still remained a mystery. We, therefore, undertook a systems biomedicine approach to identify the network of gene products implicated in rabies. This was done by meta-analyzing whole-transcriptome microarray datasets of the CNS infected by strain CVS-11, and integrating them with interactome data using computational and statistical methods. We first determined the differentially expressed genes (DEGs in each study and horizontally integrated the results at the mRNA and microRNA levels separately. A total of 61 seed genes involved in signal propagation system were obtained by means of unifying mRNA and microRNA detected integrated DEGs. We then reconstructed a refined protein-protein interaction network (PPIN of infected cells to elucidate the rabies-implicated signal transduction network (RISN. To validate our findings, we confirmed differential expression of randomly selected genes in the network using Real-time PCR. In conclusion, the identification of seed genes and their network neighborhood within the refined PPIN can be useful for demonstrating signaling pathways including interferon circumvent, toward proliferation and survival, and neuropathological clue, explaining the intricate underlying molecular neuropathology of rabies infection and thus rendered a molecular framework for predicting potential drug targets.

  12. Systems Biomedicine of Rabies Delineates the Affected Signaling Pathways

    Science.gov (United States)

    Azimzadeh Jamalkandi, Sadegh; Mozhgani, Sayed-Hamidreza; Gholami Pourbadie, Hamid; Mirzaie, Mehdi; Noorbakhsh, Farshid; Vaziri, Behrouz; Gholami, Alireza; Ansari-Pour, Naser; Jafari, Mohieddin

    2016-01-01

    The prototypical neurotropic virus, rabies, is a member of the Rhabdoviridae family that causes lethal encephalomyelitis. Although there have been a plethora of studies investigating the etiological mechanism of the rabies virus and many precautionary methods have been implemented to avert the disease outbreak over the last century, the disease has surprisingly no definite remedy at its late stages. The psychological symptoms and the underlying etiology, as well as the rare survival rate from rabies encephalitis, has still remained a mystery. We, therefore, undertook a systems biomedicine approach to identify the network of gene products implicated in rabies. This was done by meta-analyzing whole-transcriptome microarray datasets of the CNS infected by strain CVS-11, and integrating them with interactome data using computational and statistical methods. We first determined the differentially expressed genes (DEGs) in each study and horizontally integrated the results at the mRNA and microRNA levels separately. A total of 61 seed genes involved in signal propagation system were obtained by means of unifying mRNA and microRNA detected integrated DEGs. We then reconstructed a refined protein–protein interaction network (PPIN) of infected cells to elucidate the rabies-implicated signal transduction network (RISN). To validate our findings, we confirmed differential expression of randomly selected genes in the network using Real-time PCR. In conclusion, the identification of seed genes and their network neighborhood within the refined PPIN can be useful for demonstrating signaling pathways including interferon circumvent, toward proliferation and survival, and neuropathological clue, explaining the intricate underlying molecular neuropathology of rabies infection and thus rendered a molecular framework for predicting potential drug targets. PMID:27872612

  13. Systems Biomedicine of Rabies Delineates the Affected Signaling Pathways.

    Science.gov (United States)

    Azimzadeh Jamalkandi, Sadegh; Mozhgani, Sayed-Hamidreza; Gholami Pourbadie, Hamid; Mirzaie, Mehdi; Noorbakhsh, Farshid; Vaziri, Behrouz; Gholami, Alireza; Ansari-Pour, Naser; Jafari, Mohieddin

    2016-01-01

    The prototypical neurotropic virus, rabies, is a member of the Rhabdoviridae family that causes lethal encephalomyelitis. Although there have been a plethora of studies investigating the etiological mechanism of the rabies virus and many precautionary methods have been implemented to avert the disease outbreak over the last century, the disease has surprisingly no definite remedy at its late stages. The psychological symptoms and the underlying etiology, as well as the rare survival rate from rabies encephalitis, has still remained a mystery. We, therefore, undertook a systems biomedicine approach to identify the network of gene products implicated in rabies. This was done by meta-analyzing whole-transcriptome microarray datasets of the CNS infected by strain CVS-11, and integrating them with interactome data using computational and statistical methods. We first determined the differentially expressed genes (DEGs) in each study and horizontally integrated the results at the mRNA and microRNA levels separately. A total of 61 seed genes involved in signal propagation system were obtained by means of unifying mRNA and microRNA detected integrated DEGs. We then reconstructed a refined protein-protein interaction network (PPIN) of infected cells to elucidate the rabies-implicated signal transduction network (RISN). To validate our findings, we confirmed differential expression of randomly selected genes in the network using Real-time PCR. In conclusion, the identification of seed genes and their network neighborhood within the refined PPIN can be useful for demonstrating signaling pathways including interferon circumvent, toward proliferation and survival, and neuropathological clue, explaining the intricate underlying molecular neuropathology of rabies infection and thus rendered a molecular framework for predicting potential drug targets.

  14. Resveratrol induces autophagy by directly inhibiting mTOR through ATP competition

    Science.gov (United States)

    Park, Dohyun; Jeong, Heeyoon; Lee, Mi Nam; Koh, Ara; Kwon, Ohman; Yang, Yong Ryoul; Noh, Jungeun; Suh, Pann-Ghill; Park, Hwangseo; Ryu, Sung Ho

    2016-01-01

    Resveratrol (RSV) is a natural polyphenol that has a beneficial effect on health, and resveratrol-induced autophagy has been suggested to be a key process in mediating many beneficial effects of resveratrol, such as reduction of inflammation and induction of cancer cell death. Although various resveratrol targets have been suggested, the molecule that mediates resveratrol-induced autophagy remains unknown. Here, we demonstrate that resveratrol induces autophagy by directly inhibiting the mTOR-ULK1 pathway. We found that inhibition of mTOR activity and presence of ULK1 are required for autophagy induction by resveratrol. In line with this mTOR dependency, we found that resveratrol suppresses the viability of MCF7 cells but not of SW620 cells, which are mTOR inhibitor sensitive and insensitive cancer cells, respectively. We also found that resveratrol-induced cancer cell suppression occurred ULK1 dependently. For the mechanism of action of resveratrol on mTOR inhibition, we demonstrate that resveratrol directly inhibits mTOR. We found that resveratrol inhibits mTOR by docking onto the ATP-binding pocket of mTOR (i.e., it competes with ATP). We propose mTOR as a novel direct target of resveratrol, and inhibition of mTOR is necessary for autophagy induction. PMID:26902888

  15. Study on the relationship between PI3K/AKT signaling pathway and apoptosis in cartilage tissue of rats with osteoarthritis

    Directory of Open Access Journals (Sweden)

    Xiao-Yan Li

    2017-05-01

    Full Text Available Objective: To study the relationship between PI3K/AKT signaling pathway and apoptosis in cartilage tissue of rats with osteoarthritis (OA. Methods: The clean male Wistar rats were selected as experimental animals and randomly divided into OA model group and control group. The OA model was established by intra-articular injection of papain solution and L-cysteine. Fourth weeks and eighth weeks after model establishment, the expression of PI3K/AKT signaling molecules, inflammatory mediators, apoptosis marker molecules and autophagy marker molecules in articular cartilage were determined. Results: p-PI3K and p-AKT expression in articular cartilage of OA group were significantly lower than those of control group; IL-1β, IL-6, IL-17, IL-18, eIF4E, Bax, Caspase-3, mTOR, Beclin1, Atg5 and Atg7 expression in articular cartilage of OA group were significantly higher than those of control group and negatively correlated with p-PI3K and p-AKT expression while Bcl-2 expression in articular cartilage of OA group was significantly lower than that of control group and positively correlated with p-PI3K and p-AKT expression. Conclusion: The inhibition of PI3K/AKT signaling pathway in cartilage tissue of OA rat model can promote chondrocyte apoptosis and autophagy.

  16. Signals of Ezh2, Src, and Akt Involve in Myostatin-Pax7 Pathways Regulating the Myogenic Fate Determination during the Sheep Myoblast Proliferation and Differentiation

    Science.gov (United States)

    Li, Li; Liu, Ruizao; Zhang, Li; Zhao, Fuping; Lu, Jian; Zhang, Xiaoning; Du, Lixin

    2015-01-01

    Myostatin and Pax7 have been well documented individually, however, the mechanism by which Myostatin regulates Pax7 is seldom reported. Here, based on muscle transcriptome analysis in Texel (Myostatin mutant) and Ujumqin (wild type) sheep across the five fetal stages, we constructed and examined the Myostatin-Pax7 pathways in muscle. Then we validated the signals by RNAi in the proliferating and differentiating sheep myoblasts in vitro at mRNA, protein, and cell morphological levels. We reveal that Myostatin signals to Pax7 at least through Ezh2, Src, and Akt during the sheep myoblast proliferation and differentiation. Other signals such as p38MAPK, mTOR, Erk1/2, Wnt, Bmp2, Smad, Tgfb1, and p21 are most probably involved in the Myostatin-affected myogenic events. Myostatin knockdown significantly reduces the counts of nucleus and myotube, but not the fusion index of myoblasts during cell differentiation. In addition, findings also indicate that Myostatin is required for normal myogenic differentiation of the sheep myoblasts, which is different from the C2C12 myoblasts. We expand the regulatory network of Myostatin-Pax7 pathways and first illustrate that Myostatin as a global regulator participates in the epigenetic events involved in myogenesis, which contributes to understand the molecular mechanism of Myostatin in regulation of myogenesis. PMID:25811841

  17. Telocinobufagin inhibits the epithelial-mesenchymal transition of breast cancer cells through the phosphoinositide 3-kinase/protein kinase B/extracellular signal-regulated kinase/Snail signaling pathway.

    Science.gov (United States)

    Gao, Yuxue; Shi, Lihong; Cao, Zhen; Zhu, Xuetao; Li, Feng; Wang, Ruyan; Xu, Jinyuan; Zhong, Jinyi; Zhang, Baogang; Lu, Shijun

    2018-05-01

    Telocinobufagin (TBG), an active ingredient of Venenumbufonis , exhibits an immunomodulatory activity. However, its antimetastatic activity in breast cancer remains unknown. The present study investigated whether TBG prevents breast cancer metastasis and evaluated its regulatory mechanism. TBG inhibited the migration and invasion of 4T1 breast cancer cells. Furthermore, TBG triggered the collapse of F-actin filaments in breast cancer. The epithelial-mesenchymal transition (EMT) markers, vimentin and fibronectin, were downregulated following TBG treatment. However, E-cadherin was upregulated following TBG treatment. Snail, a crucial transcriptional factor of EMT, was downregulated following TBG treatment. Signaling pathway markers, including phosphorylated protein kinase B (P-Akt), p-mechanistic target of rapamycin (mTOR) and p-extracellular signal-regulated kinase (ERK), were decreased following TBG treatment. The same results were obtained from in vivo experiments. In conclusion, in vitro and in vivo experiments reveal that TBG inhibited migration, invasion and EMT via the phosphoinositide 3-kinase (PI3K)/Akt/ERK/Snail signaling pathway in breast cancer.

  18. mTOR regulates the expression of DNA damage response enzymes in long-lived Snell dwarf, GHRKO, and PAPPA-KO mice.

    Science.gov (United States)

    Dominick, Graham; Bowman, Jacqueline; Li, Xinna; Miller, Richard A; Garcia, Gonzalo G

    2017-02-01

    Studies of the mTOR pathway have prompted speculation that diminished mTOR complex-1 (mTORC1) function may be involved in controlling the aging process. Our previous studies have shown diminished mTORC1 activity in tissues of three long-lived mutant mice: Snell dwarf mice, growth hormone receptor gene disrupted mice (GHRKO), and in this article, mice deficient in the pregnancy-associated protein-A (PAPPA-KO). The ways in which lower mTOR signals slow aging and age-related diseases are, however, not well characterized. Here, we show that Snell, GHKRO, and PAPPA-KO mice express high levels of two proteins involved in DNA repair, O-6-methylguanine-DNA methyltransferase (MGMT) and N-myc downstream-regulated gene 1 (NDRG1). Furthermore, we report that lowering mTOR enhances MGMT and NDRG1 protein expression via post-transcriptional mechanisms. We show that the CCR4-NOT complex, a post-transcriptional regulator of gene expression, is downstream of the mTORC1 pathway and may be responsible for the upregulation of MGMT and NDRG1 in all three varieties of long-lived mice. Our data thus suggest a novel link between DNA repair and mTOR signaling via post-transcriptional regulation involving specific alteration in the CCR4-NOT complex, whose modulation could control multiple aspects of the aging process. © 2016 The Authors. Aging Cell published by the Anatomical Society and John Wiley & Sons Ltd.

  19. Nuclear Receptor Signaling Atlas: Opening Access to the Biology of Nuclear Receptor Signaling Pathways.

    Science.gov (United States)

    Becnel, Lauren B; Darlington, Yolanda F; Ochsner, Scott A; Easton-Marks, Jeremy R; Watkins, Christopher M; McOwiti, Apollo; Kankanamge, Wasula H; Wise, Michael W; DeHart, Michael; Margolis, Ronald N; McKenna, Neil J

    2015-01-01

    Signaling pathways involving nuclear receptors (NRs), their ligands and coregulators, regulate tissue-specific transcriptomes in diverse processes, including development, metabolism, reproduction, the immune response and neuronal function, as well as in their associated pathologies. The Nuclear Receptor Signaling Atlas (NURSA) is a Consortium focused around a Hub website (www.nursa.org) that annotates and integrates diverse 'omics datasets originating from the published literature and NURSA-funded Data Source Projects (NDSPs). These datasets are then exposed to the scientific community on an Open Access basis through user-friendly data browsing and search interfaces. Here, we describe the redesign of the Hub, version 3.0, to deploy "Web 2.0" technologies and add richer, more diverse content. The Molecule Pages, which aggregate information relevant to NR signaling pathways from myriad external databases, have been enhanced to include resources for basic scientists, such as post-translational modification sites and targeting miRNAs, and for clinicians, such as clinical trials. A portal to NURSA's Open Access, PubMed-indexed journal Nuclear Receptor Signaling has been added to facilitate manuscript submissions. Datasets and information on reagents generated by NDSPs are available, as is information concerning periodic new NDSP funding solicitations. Finally, the new website integrates the Transcriptomine analysis tool, which allows for mining of millions of richly annotated public transcriptomic data points in the field, providing an environment for dataset re-use and citation, bench data validation and hypothesis generation. We anticipate that this new release of the NURSA database will have tangible, long term benefits for both basic and clinical research in this field.

  20. Nuclear Receptor Signaling Atlas: Opening Access to the Biology of Nuclear Receptor Signaling Pathways.

    Directory of Open Access Journals (Sweden)

    Lauren B Becnel

    Full Text Available Signaling pathways involving nuclear receptors (NRs, their ligands and coregulators, regulate tissue-specific transcriptomes in diverse processes, including development, metabolism, reproduction, the immune response and neuronal function, as well as in their associated pathologies. The Nuclear Receptor Signaling Atlas (NURSA is a Consortium focused around a Hub website (www.nursa.org that annotates and integrates diverse 'omics datasets originating from the published literature and NURSA-funded Data Source Projects (NDSPs. These datasets are then exposed to the scientific community on an Open Access basis through user-friendly data browsing and search interfaces. Here, we describe the redesign of the Hub, version 3.0, to deploy "Web 2.0" technologies and add richer, more diverse content. The Molecule Pages, which aggregate information relevant to NR signaling pathways from myriad external databases, have been enhanced to include resources for basic scientists, such as post-translational modification sites and targeting miRNAs, and for clinicians, such as clinical trials. A portal to NURSA's Open Access, PubMed-indexed journal Nuclear Receptor Signaling has been added to facilitate manuscript submissions. Datasets and information on reagents generated by NDSPs are available, as is information concerning periodic new NDSP funding solicitations. Finally, the new website integrates the Transcriptomine analysis tool, which allows for mining of millions of richly annotated public transcriptomic data points in the field, providing an environment for dataset re-use and citation, bench data validation and hypothesis generation. We anticipate that this new release of the NURSA database will have tangible, long term benefits for both basic and clinical research in this field.

  1. Comparison of Akt/mTOR/4E-BP1 pathway signal activation and mutations of PIK3CA in Merkel cell polyomavirus-positive and Merkel cell polyomavirus-negative carcinomas.

    Science.gov (United States)

    Iwasaki, Takeshi; Matsushita, Michiko; Nonaka, Daisuke; Kuwamoto, Satoshi; Kato, Masako; Murakami, Ichiro; Nagata, Keiko; Nakajima, Hideki; Sano, Shigetoshi; Hayashi, Kazuhiko

    2015-02-01

    Merkel cell polyomavirus (MCPyV) integrates monoclonally into the genomes of approximately 80% of Merkel cell carcinomas (MCCs), affecting their clinicopathological features. The molecular mechanisms underlying MCC development after MCPyV infection remain unclear. We investigated the association of MCPyV infection with activation of the Akt/mammalian target of rapamycin (mTOR)/4E-binding protein 1 (4E-BP1) signaling pathway in MCCs to elucidate the role of these signal transductions and to identify molecular targets for treatment. We analyzed the molecular and pathological characteristics of 41 MCPyV-positive and 27 MCPyV-negative MCCs. Expression of mTOR, TSC1, and TSC2 messenger RNA was significantly higher in MCPyV-negative MCCs, and Akt (T308) phosphorylation also was significantly higher (92% vs 66%; P = .019), whereas 4E-BP1 (S65 and T70) phosphorylation was common in both MCC types (92%-100%). The expression rates of most other tested signals were high (60%-100%) and not significantly correlated with MCPyV large T antigen expression. PIK3CA mutations were observed more frequently in MCPyV-positive MCCs (6/36 [17%] vs 2/20 [10%]). These results suggest that protein expression (activation) of most Akt/mTOR/4E-BP1 pathway signals was not significantly different in MCPyV-positive and MCPyV-negative MCCs, although these 2 types may differ in tumorigenesis, and MCPyV-negative MCCs showed significantly more frequent p-Akt (T308) activation. Therefore, certain Akt/mTOR/4E-BP1 pathway signals could be novel therapeutic targets for MCC regardless of MCPyV infection status. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Plasticity and mTOR: Towards Restoration of Impaired Synaptic Plasticity in mTOR-Related Neurogenetic Disorders

    Directory of Open Access Journals (Sweden)

    Tanjala T. Gipson

    2012-01-01

    Full Text Available Objective. To review the recent literature on the clinical features, genetic mutations, neurobiology associated with dysregulation of mTOR (mammalian target of rapamycin, and clinical trials for tuberous sclerosis complex (TSC, neurofibromatosis-1 (NF1 and fragile X syndrome (FXS, and phosphatase and tensin homolog hamartoma syndromes (PTHS, which are neurogenetic disorders associated with abnormalities in synaptic plasticity and mTOR signaling. Methods. Pubmed and Clinicaltrials.gov were searched using specific search strategies. Results/Conclusions. Although traditionally thought of as irreversible disorders, significant scientific progress has been made in both humans and preclinical models to understand how pathologic features of these neurogenetic disorders can be reduced or reversed. This paper revealed significant similarities among the conditions. Not only do they share features of impaired synaptic plasticity and dysregulation of mTOR, but they also share clinical features—autism, intellectual disability, cutaneous lesions, and tumors. Although scientific advances towards discovery of effective treatment in some disorders have outpaced others, progress in understanding the signaling pathways that connect the entire group indicates that the lesser known disorders will become treatable as well.

  3. In Vivo Characterization of Intracellular Signaling Pathways Activated by the Nerve Agent Sarin

    National Research Council Canada - National Science Library

    Shih, Tsung-Ming A; Snyder, Gretchen L; Hendrick, Joseph P; Fienberg, Allen A; McDonough, John H

    2004-01-01

    ..., an excessive stimulation of nicotinic and muscarinic receptors. Preliminary evidence using diverse OPs indicates that the DARPP-32/PP-1 signaling pathway is activated by nicotinic receptor stimulation...

  4. Molecular Signaling Pathways Mediating Osteoclastogenesis Induced by Prostate Cancer Cells

    International Nuclear Information System (INIS)

    Rafiei, Shahrzad; Komarova, Svetlana V

    2013-01-01

    Advanced prostate cancer commonly metastasizes to bone leading to osteoblastic and osteolytic lesions. Although an osteolytic component governed by activation of bone resorbing osteoclasts is prominent in prostate cancer metastasis, the molecular mechanisms of prostate cancer-induced osteoclastogenesis are not well-understood. We studied the effect of soluble mediators released from human prostate carcinoma cells on osteoclast formation from mouse bone marrow and RAW 264.7 monocytes. Soluble factors released from human prostate carcinoma cells significantly increased viability of naïve bone marrow monocytes, as well as osteoclastogenesis from precursors primed with receptor activator of nuclear factor κ-B ligand (RANKL). The prostate cancer-induced osteoclastogenesis was not mediated by RANKL as it was not inhibited by osteoprotegerin (OPG). However inhibition of TGFβ receptor I (TβRI), or macrophage-colony stimulating factor (MCSF) resulted in attenuation of prostate cancer-induced osteoclastogenesis. We characterized the signaling pathways induced in osteoclast precursors by soluble mediators released from human prostate carcinoma cells. Prostate cancer factors increased basal calcium levels and calcium fluctuations, induced nuclear localization of nuclear factor of activated t-cells (NFAT)c1, and activated prolonged phosphorylation of ERK1/2 in RANKL-primed osteoclast precursors. Inhibition of calcium signaling, NFATc1 activation, and ERK1/2 phosphorylation significantly reduced the ability of prostate cancer mediators to stimulate osteoclastogenesis. This study reveals the molecular mechanisms underlying the direct osteoclastogenic effect of prostate cancer derived factors, which may be beneficial in developing novel osteoclast-targeting therapeutic approaches

  5. ent-Steroids: novel tools for studies of signaling pathways.

    Science.gov (United States)

    Covey, Douglas F

    2009-07-01

    Membrane receptors are often modulated by steroids and it is necessary to distinguish the effects of steroids at these receptors from effects occurring at nuclear receptors. Additionally, it may also be mechanistically important to distinguish between direct effects caused by binding of steroids to membrane receptors and indirect effects on membrane receptor function caused by steroid perturbation of the membrane containing the receptor. In this regard, ent-steroids, the mirror images of naturally occurring steroids, are novel tools for distinguishing between these various actions of steroids. The review provides a background for understanding the different actions that can be expected of steroids and ent-steroids in biological systems, references for the preparation of ent-steroids, a short discussion about relevant forms of stereoisomerism and the requirements that need to be fulfilled for the interaction between two molecules to be enantioselective. The review then summarizes results of biophysical, biochemical and pharmacological studies published since 1992 in which ent-steroids have been used to investigate the actions of steroids in membranes and/or receptor-mediated signaling pathways.

  6. Functional comparison of innate immune signaling pathways in primates.

    Directory of Open Access Journals (Sweden)

    Luis B Barreiro

    2010-12-01

    Full Text Available Humans respond differently than other primates to a large number of infections. Differences in susceptibility to infectious agents between humans and other primates are probably due to inter-species differences in immune response to infection. Consistent with that notion, genes involved in immunity-related processes are strongly enriched among recent targets of positive selection in primates, suggesting that immune responses evolve rapidly, yet providing only indirect evidence for possible inter-species functional differences. To directly compare immune responses among primates, we stimulated primary monocytes from humans, chimpanzees, and rhesus macaques with lipopolysaccharide (LPS and studied the ensuing time-course regulatory responses. We find that, while the universal Toll-like receptor response is mostly conserved across primates, the regulatory response associated with viral infections is often lineage-specific, probably reflecting rapid host-virus mutual adaptation cycles. Additionally, human-specific immune responses are enriched for genes involved in apoptosis, as well as for genes associated with cancer and with susceptibility to infectious diseases or immune-related disorders. Finally, we find that chimpanzee-specific immune signaling pathways are enriched for HIV-interacting genes. Put together, our observations lend strong support to the notion that lineage-specific immune responses may help explain known inter-species differences in susceptibility to infectious diseases.

  7. Erythrocyte signal transduction pathways, their oxygenation dependence and functional significance.

    Science.gov (United States)

    Barvitenko, Nadezhda N; Adragna, Norma C; Weber, Roy E

    2005-01-01

    Erythrocytes play a key role in human and vertebrate metabolism. Tissue O2 supply is regulated by both hemoglobin (Hb)-O2 affinity and erythrocyte rheology, a key determinant of tissue perfusion. Oxygenation-deoxygenation transitions of Hb may lead to re-organization of the cytoskeleton and signalling pathways activation/deactivation in an O2-dependent manner. Deoxygenated Hb binds to the cytoplasmic domain of the anion exchanger band 3, which is anchored to the cytoskeleton, and is considered a major mechanism underlying the oxygenation-dependence of several erythrocyte functions. This work discusses the multiple modes of Hb-cytoskeleton interactions. In addition, it reviews the effects of Mg2+, 2,3-diphosphoglycerate, NO, shear stress and Ca2+, all factors accompanying the oxygenation-deoxygenation cycle in circulating red cells. Due to the extensive literature on the subject, the data discussed here, pertain mainly to human erythrocytes whose O2 affinity is modulated by 2,3-diphosphoglycerate, ectothermic vertebrate erythrocytes that use ATP, and to bird erythrocytes that use inositol pentaphosphate. Copyright 2005 S. Karger AG, Basel.

  8. The Wnt signaling pathway in familial exudative vitreoretinopathy and Norrie disease.

    Science.gov (United States)

    Warden, Scott M; Andreoli, Christopher M; Mukai, Shizuo

    2007-01-01

    The Wnt signaling pathway is highly conserved among species and has an important role in many cell biological processes throughout the body. This signaling cascade is involved in regulating ocular growth and development, and recent findings indicate that this is particularly true in the retina. Mutations involving different aspects of the Wnt signaling pathway are being linked to several diseases of retinal development. The aim of this article is to first review the Wnt signaling pathway. We will then describe two conditions, familial exudative vitreoretinopathy (FEVR) and Norrie disease (ND), which have been shown to be caused in part by defects in the Wnt signaling cascade.

  9. Urotensin II inhibits skeletal muscle glucose transport signaling pathways via the NADPH oxidase pathway.

    Directory of Open Access Journals (Sweden)

    Hong-Xia Wang

    Full Text Available Our previous studies have demonstrated that the urotensin (UII and its receptor are up-regulated in the skeletal muscle of mice with type II diabetes mellitus (T2DM, but the significance of UII in skeletal muscle insulin resistance remains unknown. The purpose of this study was to investigate the effect of UII on NADPH oxidase and glucose transport signaling pathways in the skeletal muscle of mice with T2DM and in C2C12 mouse myotube cells. KK/upj-AY/J mice (KK mice were divided into the following groups: KK group, with saline treatment for 2 weeks; KK+ urantide group, with daily 30 µg/kg body weight injections over the same time period of urantide, a potent urotensin II antagonist peptide; Non-diabetic C57BL/6J mice were used as normal controls. After urantide treatment, mice were subjected to an intraperitoneal glucose tolerance test, in addition to measurements of the levels of ROS, NADPH oxidase and the phosphorylated AKT, PKC and ERK. C2C12 cells were incubated with serum-free DMEM for 24 hours before conducting the experiments, and then administrated with 100 nM UII for 2 hours or 24 hours. Urantide treatment improved glucose tolerance, decreased the translocation of the NADPH subunits p40-phox and p47-phox, and increased levels of the phosphorylated PKC, AKT and ERK. In contrast, UII treatment increased ROS production and p47-phox and p67-phox translocation, and decreased the phosphorylated AKT, ERK1/2 and p38MAPK; Apocynin abrogated this effect. In conclusion, UII increased ROS production by NADPH oxidase, leading to the inhibition of signaling pathways involving glucose transport, such as AKT/PKC/ERK. Our data imply a role for UII at the molecular level in glucose homeostasis, and possibly in skeletal muscle insulin resistance in T2DM.

  10. MicroRNA-99 family targets AKT/mTOR signaling pathway in dermal wound healing.

    Science.gov (United States)

    Jin, Yi; Tymen, Stéphanie D; Chen, Dan; Fang, Zong Juan; Zhao, Yan; Dragas, Dragan; Dai, Yang; Marucha, Phillip T; Zhou, Xiaofeng

    2013-01-01

    Recent studies suggest that microRNAs play important roles in dermal wound healing and microRNA deregulation has been linked with impaired wound repair. Here, using a mouse experimental wound healing model, we identified a panel of 63 differentially expressed microRNAs during dermal wound healing, including members of miR-99 family (miR-99a, miR-99b, miR-100). We further demonstrated that miR-99 family members regulate cell proliferation, cell migration, and AKT/mTOR signaling. Combined experimental and bioinformatics analyses revealed that miR-99 family members regulate AKT/mTOR signaling by targeting multiple genes, including known target genes (e.g., IGF1R, mTOR) and a new target (AKT1). The effects of miR-99 family members on the expression of IGF1R, mTOR and AKT1 were validated at both the mRNA and protein levels. Two adjacent miR-99 family targeting sites were identified in the 3'-UTR of the AKT1 mRNA. The direct interaction of miR-100 with these targeting sites was confirmed using luciferase reporter assays. The microRNA-100-directed recruitment of AKT1 mRNA to the RNAi-induced silencing complex (RISC) was confirmed by a ribonucleoprotein-IP assay. In summary, we identified a panel of differentially expressed microRNAs which may play important roles in wound healing. We provide evidence that miR-99 family members contribute to wound healing by regulating the AKT/mTOR signaling.

  11. Testosterone induces molecular changes in dopamine signaling pathway molecules in the adolescent male rat nigrostriatal pathway.

    Directory of Open Access Journals (Sweden)

    Tertia D Purves-Tyson

    Full Text Available Adolescent males have an increased risk of developing schizophrenia, implicating testosterone in the precipitation of dopamine-related psychopathology. Evidence from adult rodent brain indicates that testosterone can modulate nigrostriatal dopamine. However, studies are required to understand the role testosterone plays in maturation of dopamine pathways during adolescence and to elucidate the molecular mechanism(s by which testosterone exerts its effects. We hypothesized that molecular indices of dopamine neurotransmission [synthesis (tyrosine hydroxylase, breakdown (catechol-O-methyl transferase; monoamine oxygenase, transport [vesicular monoamine transporter (VMAT, dopamine transporter (DAT] and receptors (DRD1-D5] would be changed by testosterone or its metabolites, dihydrotestosterone and 17β-estradiol, in the nigrostriatal pathway of adolescent male rats. We found that testosterone and dihydrotestosterone increased DAT and VMAT mRNAs in the substantia nigra and that testosterone increased DAT protein at the region of the cell bodies, but not in target regions in the striatum. Dopamine receptor D2 mRNA was increased and D3 mRNA was decreased in substantia nigra and/or striatum by androgens. These data suggest that increased testosterone at adolescence may change dopamine responsivity of the nigrostriatal pathway by modulating, at a molecular level, the capacity of neurons to transport and respond to dopamine. Further, dopamine turnover was increased in the dorsal striatum following gonadectomy and this was prevented by testosterone replacement. Gene expression changes in the dopaminergic cell body region may serve to modulate both dendritic dopamine feedback inhibition and reuptake in the dopaminergic somatodendritic field as well as dopamine release and re-uptake dynamics at the presynaptic terminals in the striatum. These testosterone-induced changes of molecular indices of dopamine neurotransmission in males are primarily androgen

  12. Promotion of ovarian follicle growth following mTOR activation: synergistic effects of AKT stimulators.

    Directory of Open Access Journals (Sweden)

    Yuan Cheng

    Full Text Available Mammalian target of rapamycin (mTOR is a serine/threonine kinase and mTOR signaling is important in regulating cell growth and proliferation. Recent studies using oocyte- and granulosa cell-specific deletion of mTOR inhibitor genes TSC1 or TSC2 demonstrated the important role of mTOR signaling in the promotion of ovarian follicle development. We now report that treatment of ovaries from juvenile mice with an mTOR activator MHY1485 stimulated mTOR, S6K1 and rpS6 phosphorylation. Culturing ovaries for 4 days with MHY1485 increased ovarian explant weights and follicle development. In vivo studies further demonstrated that pre-incubation of these ovaries with MHY1485 for 2 days, followed by allo-grafting into kidney capsules of adult ovariectomized hosts for 5 days, led to marked increases in graft weights and promotion of follicle development. Mature oocytes derived from MHY1485-activated ovarian grafts could be successfully fertilized, leading the delivery of healthy pups. We further treated ovaries with the mTOR activator together with AKT activators (PTEN inhibitor and phosphoinositol-3-kinase stimulator before grafting and found additive enhancement of follicle growth. Our studies demonstrate the ability of an mTOR activator in promoting follicle growth, leading to a potential strategy to stimulate preantral follicle growth in infertile patients.

  13. PI3K-Akt signaling activates mTOR-mediated epileptogenesis in organotypic hippocampal culture model of posttraumatic epilepsy

    Science.gov (United States)

    Berdichevsky, Yevgeny; Dryer, Alexandra M.; Saponjian, Yero; Mahoney, Mark M.; Pimentel, Corrin A.; Lucini, Corrina A.; Usenovic, Marija; Staley, Kevin J.

    2013-01-01

    mTOR is activated in epilepsy, but the mechanisms of mTOR activation in post-traumatic epileptogenesis are unknown. It is also not clear whether mTOR inhibition has an antiepileptogenic, or merely anti-convulsive effect. The rat hippocampal organotypic culture model of post-traumatic epilepsy was used to study the effects of long term (four weeks) inhibition of signaling pathways that interact with mTOR. Ictal activity was quantified by measurement of lactate production and electrical recordings, and cell death was quantified with LDH release measurements and Nissl-stained neuron counts. Lactate and LDH measurements were well-correlated with electrographic activity and neuron counts, respectively. Inhibition of PI3K and Akt prevented activation of mTOR, and was as effective as inhibition of mTOR in reducing ictal activity and cell death. A dual inhibitor of PI3K and mTOR, NVP-BEZ235, was also effective. Inhibition of mTOR with rapamycin reduced axon sprouting. Late start of rapamycin treatment was effective in reducing epileptic activity and cell death, while early termination of rapamycin treatment did not result in increased epileptic activity or cell death. The conclusions of the study are: (1), the organotypic hippocampal culture model of posttraumatic epilepsy comprises a rapid assay of antiepileptogenic and neuroprotective activities and, in this model (2), mTOR activation depends on PI3K-Akt signaling, and (3) transient inhibition of mTOR has sustained effects on epilepsy. PMID:23699517

  14. Pirarubicin induces an autophagic cytoprotective response through suppression of the mammalian target of rapamycin signaling pathway in human bladder cancer cells

    International Nuclear Information System (INIS)

    Li, Kuiqing; Chen, Xu; Liu, Cheng; Gu, Peng; Li, Zhuohang; Wu, Shaoxu; Xu, Kewei; Lin, Tianxin; Huang, Jian

    2015-01-01

    Pirarubicin is widely used in intravesical chemotherapy for bladder cancer, but its efficacy is limited due to drug resistance; the mechanism has not been well studied. Emerging evidence shows that autophagy can be a novel target for cancer therapy. This study aimed to investigate the role of autophagy in pirarubicin-treated bladder cancer cells. Bladder cancer cells EJ and J82 were treated with pirarubicin, siRNA, 3-methyladenine or hydroxychloroquine. Cell proliferation and apoptosis were tested by cell survival assay and flow cytometric analysis, respectively. Autophagy was evaluated by immunoblotting before and after the treatments. The phosphorylated mammalian target of rapamycin, serine/threonine kinase p70 S6 kinase, and eukaryotic translation initiation factor 4E binding protein 1 were also investigated by immunoblotting. We found that pirarubicin could induce autophagy in bladder cancer cells. Inhibition of autophagy by 3-methyladenine, hydroxychloroquine or knockdown of autophagy related gene 3 significantly increased apoptosis in pirarubicin-treated bladder cancer cells. Pirarubicin-induced autophagy was mediated via the mTOR/p70S6K/4E-BP1 signaling pathway. In conclusion, autophagy induced by pirarubicin plays a cytoprotective role in bladder cancer cells, suggesting that inhibition of autophagy may improve efficacy over traditional pirarubicin chemotherapy in bladder cancer patients. - Highlights: • Pirarubicin induced autophagy in bladder cancer cells. • Inhibition of autophagy enhanced pirarubicin-induced apoptosis. • Pirarubicin induced autophagy through inhibition of mTOR signaling pathway

  15. Trillium tschonoskii maxim saponin mitigates D-galactose-induced brain aging of rats through rescuing dysfunctional autophagy mediated by Rheb-mTOR signal pathway.

    Science.gov (United States)

    Wang, Lingjie; Du, Junlong; Zhao, Fangyu; Chen, Zonghai; Chang, Jingru; Qin, Furong; Wang, Zili; Wang, Fengjie; Chen, Xianbing; Chen, Ning

    2018-02-01

    During the expansion of aging population, the study correlated with brain aging is one of the important research topics. Developing novel and effective strategies for delaying brain aging is highly desired. Brain aging is characteristics of impaired cognitive capacity due to dysfunctional autophagy regulated by Rheb-mTOR signal pathway in hippocampal tissues. In the present study, we have established a rat model with brain aging through subcutaneous injection of D-galactose (D-gal). Upon the intervention of Trillium tschonoskii Maxim (TTM) saponin, one of bioactive components from local natural herbs in China, the learning and memory capacity of D-gal-induced aging rats was evaluated through Morris water maze test, and the regulation of Rheb-mTOR signal pathway and functional status of autophagy in hippocampal tissues of D-gal-induced aging rats was explored by Western blot. TTM saponin revealed an obvious function to improve learning and memory capacity of D-gal-induced aging rats through up-regulating Rheb and down-regulating mTOR, thereby rescuing dysfunctional autophagy to execute anti-aging role. Meanwhile, this study confirmed the function of TTM saponin for preventing and treating brain aging, and provided a reference for the development and utilization of natural products in health promotion and aging-associated disease treatment. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  16. Pirarubicin induces an autophagic cytoprotective response through suppression of the mammalian target of rapamycin signaling pathway in human bladder cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Li, Kuiqing; Chen, Xu [Department of Urology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou 510120 (China); Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou 510120 (China); Liu, Cheng [Department of Urology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou 510120 (China); Gu, Peng; Li, Zhuohang; Wu, Shaoxu [Department of Urology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou 510120 (China); Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou 510120 (China); Xu, Kewei [Department of Urology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou 510120 (China); Lin, Tianxin, E-mail: tianxinl@sina.com [Department of Urology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou 510120 (China); Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou 510120 (China); Huang, Jian, E-mail: urolhj@sina.com [Department of Urology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou 510120 (China)

    2015-05-01

    Pirarubicin is widely used in intravesical chemotherapy for bladder cancer, but its efficacy is limited due to drug resistance; the mechanism has not been well studied. Emerging evidence shows that autophagy can be a novel target for cancer therapy. This study aimed to investigate the role of autophagy in pirarubicin-treated bladder cancer cells. Bladder cancer cells EJ and J82 were treated with pirarubicin, siRNA, 3-methyladenine or hydroxychloroquine. Cell proliferation and apoptosis were tested by cell survival assay and flow cytometric analysis, respectively. Autophagy was evaluated by immunoblotting before and after the treatments. The phosphorylated mammalian target of rapamycin, serine/threonine kinase p70 S6 kinase, and eukaryotic translation initiation factor 4E binding protein 1 were also investigated by immunoblotting. We found that pirarubicin could induce autophagy in bladder cancer cells. Inhibition of autophagy by 3-methyladenine, hydroxychloroquine or knockdown of autophagy related gene 3 significantly increased apoptosis in pirarubicin-treated bladder cancer cells. Pirarubicin-induced autophagy was mediated via the mTOR/p70S6K/4E-BP1 signaling pathway. In conclusion, autophagy induced by pirarubicin plays a cytoprotective role in bladder cancer cells, suggesting that inhibition of autophagy may improve efficacy over traditional pirarubicin chemotherapy in bladder cancer patients. - Highlights: • Pirarubicin induced autophagy in bladder cancer cells. • Inhibition of autophagy enhanced pirarubicin-induced apoptosis. • Pirarubicin induced autophagy through inhibition of mTOR signaling pathway.

  17. Targeting Wnt signaling in colorectal cancer. A Review in the Theme: Cell Signaling: Proteins, Pathways and Mechanisms

    Science.gov (United States)

    Novellasdemunt, Laura; Antas, Pedro

    2015-01-01

    The evolutionarily conserved Wnt signaling pathway plays essential roles during embryonic development and tissue homeostasis. Notably, comprehensive genetic studies in Drosophila and mice in the past decades have demonstrated the crucial role of Wnt signaling in intestinal stem cell maintenance by regulating proliferation, differentiation, and cell-fate decisions. Wnt signaling has also been implicated in a variety of cancers and other diseases. Loss of the Wnt pathway negative regulator adenomatous polyposis coli (APC) is the hallmark of human colorectal cancers (CRC). Recent advances in high-throughput sequencing further reveal many novel recurrent Wnt pathway mutations in addition to the well-characterized APC and β-catenin mutations in CRC. Despite attractive strategies to develop drugs for Wnt signaling, major hurdles in therapeutic intervention of the pathway persist. Here we discuss the Wnt-activating mechanisms in CRC and review the current advances and challenges in drug discovery. PMID:26289750

  18. Wnt and the Wnt signaling pathway in bone development and disease

    Science.gov (United States)

    Wang, Yiping; Li, Yi-Ping; Paulson, Christie; Shao, Jian-Zhong; Zhang, Xiaoling; Wu, Mengrui; Chen, Wei

    2014-01-01

    Wnt signaling affects both bone modeling, which occurs during development, and bone remodeling, which is a lifelong process involving tissue renewal. Wnt signals are especially known to affect the differentiation of osteoblasts. In this review, we summarize recent advances in understanding the mechanisms of Wnt signaling, which is divided into two major branches: the canonical pathway and the noncanonical pathway. The canonical pathway is also called the Wnt/β-catenin pathway. There are two major noncanonical pathways: the Wnt-planar cell polarity pathway (Wnt-PCP pathway) and the Wnt-calcium pathway (Wnt-Ca2+ pathway). This review also discusses how Wnt ligands, receptors, intracellular effectors, transcription factors, and antagonists affect both the bone modeling and bone remodeling processes. We also review the role of Wnt ligands, receptors, intracellular effectors, transcription factors, and antagonists in bone as demonstrated in mouse models. Disrupted Wnt signaling is linked to several bone diseases, including osteoporosis, van Buchem disease, and sclerosteosis. Studying the mechanism of Wnt signaling and its interactions with other signaling pathways in bone will provide potential therapeutic targets to treat these bone diseases. PMID:24389191

  19. BLM promotes the activation of Fanconi Anemia signaling pathway.

    Science.gov (United States)

    Panneerselvam, Jayabal; Wang, Hong; Zhang, Jun; Che, Raymond; Yu, Herbert; Fei, Peiwen

    2016-05-31

    Mutations in the human RecQ helicase, BLM, causes Bloom Syndrome, which is a rare autosomal recessive disorder and characterized by genomic instability and an increased risk of cancer. Fanconi Anemia (FA), resulting from mutations in any of the 19 known FA genes and those yet to be known, is also characterized by chromosomal instability and a high incidence of cancer. BLM helicase and FA proteins, therefore, may work in a common tumor-suppressor signaling pathway. To date, it remains largely unclear as to how BLM and FA proteins work concurrently in the maintenance of genome stability. Here we report that BLM is involved in the early activation of FA group D2 protein (FANCD2). We found that FANCD2 activation is substantially delayed and attenuated in crosslinking agent-treated cells harboring deficient Blm compared to similarly treated control cells with sufficient BLM. We also identified that the domain VI of BLM plays an essential role in promoting FANCD2 activation in cells treated with DNA crosslinking agents, especially ultraviolet B. The similar biological effects performed by ΔVI-BLM and inactivated FANCD2 further confirm the relationship between BLM and FANCD2. Mutations within the domain VI of BLM detected in human cancer samples demonstrate the functional importance of this domain, suggesting human tumorigenicity resulting from mtBLM may be at least partly attributed to mitigated FANCD2 activation. Collectively, our data show a previously unknown regulatory liaison in advancing our understanding of how the cancer susceptibility gene products act in concert to maintain genome stability.

  20. Rac1 promotes chondrogenesis by regulating STAT3 signaling pathway.

    Science.gov (United States)

    Kim, Hyoin; Sonn, Jong Kyung

    2016-09-01

    The small GTPase protein Rac1 is involved in a wide range of biological processes including cell differentiation. Previously, Rac1 was shown to promote chondrogenesis in micromass cultures of limb mesenchyme. However, the pathways mediating Rac1's role in chondrogenesis are not fully understood. This study aimed to explore the molecular mechanisms by which Rac1 regulates chondrogenic differentiation. Phosphorylation of signal transducer and activator of transcription 3 (STAT3) was increased as chondrogenesis proceeded in micromass cultures of chick wing bud mesenchyme. Inhibition of Rac1 with NSC23766, janus kinase 2 (JAK2) with AG490, or STAT3 with stattic inhibited chondrogenesis and reduced phosphorylation of STAT3. Conversely, overexpression of constitutively active Rac1 (Rac L61) increased phosphorylation of STAT3. Rac L61 expression resulted in increased expression of interleukin 6 (IL-6), and treatment with IL-6 increased phosphorylation of STAT3. NSC23766, AG490, and stattic prohibited cell aggregation, whereas expression of Rac L61 increased cell aggregation, which was reduced by stattic treatment. Our studies indicate that Rac1 induces STAT3 activation through expression and action of IL-6. Overexpression of Rac L61 increased expression of bone morphogenic protein 4 (BMP4). BMP4 promoted chondrogenesis, which was inhibited by K02288, an activin receptor-like kinase-2 inhibitor, and increased phosphorylation of p38 MAP kinase. Overexpression of Rac L61 also increased phosphorylation of p38 MAPK, which was reduced by K02288. These results suggest that Rac1 activates STAT3 by expression of IL-6, which in turn increases expression and activity of BMP4, leading to the promotion of chondrogenesis. © 2016 International Federation for Cell Biology.

  1. Oncogenic signalling pathways in benign odontogenic cysts and tumours.

    Science.gov (United States)

    Diniz, Marina Gonçalves; Gomes, Carolina Cavalieri; de Sousa, Sílvia Ferreira; Xavier, Guilherme Machado; Gomez, Ricardo Santiago

    2017-09-01

    The first step towards the prevention of cancer is to develop an in-depth understanding of tumourigenesis and the molecular basis of malignant transformation. What drives tumour initiation? Why do most benign tumours fail to metastasize? Oncogenic mutations, previously considered to be the hallmark drivers of cancers, are reported in benign cysts and tumours, including those that have an odontogenic origin. Despite the presence of such alterations, the vast majority of odontogenic lesions are benign and never progress to the stage of malignant transformation. As these lesions are likely to develop due to developmental defects, it is possible that they harbour quiet genomes. Now the question arises - do they result from DNA replication errors? Specific candidate genes have been sequenced in odontogenic lesions, revealing recurrent BRAF mutation in the case of ameloblastoma, KRAS mutation in adenomatoid odontogenic tumours, PTCH1 mutation in odontogenic keratocysts, and CTNNB1 (Beta-catenin) mutation in calcifying odontogenic cysts. Studies on these benign and rare entities might reveal important information about the tumorigenic process and the mechanisms that hinder/halt neoplastic progression. This is because the role of relatively common oncogenic mutations seems to be context dependent. In this review, each mutation signature of the odontogenic lesion and the affected signalling pathways are discussed in the context of tooth development and tumorigenesis. Furthermore, behavioural differences between different types of odontogenic lesions are explored and discussed based on the molecular alteration described. This review also includes the employment of molecular results for guiding therapeutic approaches towards odontogenic lesions. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. From tyrosine to melanin: Signaling pathways and factors regulating melanogenesis

    Directory of Open Access Journals (Sweden)

    Zuzanna Rzepka

    2016-06-01

    Full Text Available Melanins are natural pigments of skin, hair and eyes and can be classified into two main types: brown to black eumelanin and yellow to reddish-brown pheomelanin. Biosynthesis of melanins takes place in melanosomes, which are specialized cytoplasmic organelles of melanocytes - dendritic cells located in the basal layer of the epidermis, uveal tract of the eye, hair follicles, as well as in the inner ear, central nervous system and heart. Melanogenesis is a multistep process and begins with the conversion of amino acid L-tyrosine to DOPAquinone. The addition of cysteine or glutathione to DOPAquinone leads to the intermediates formation, followed by subsequent transformations and polymerization to the final product, pheomelanin. In the absence of thiol compounds DOPAquinone undergoes an intramolecular cyclization and oxidation to form DOPAchrome, which is then converted to 5,6-dihydroksyindole (DHI or 5,6-dihydroxyindole-2-carboxylic acid (DHICA. Eumelanin is formed by polymerization of DHI and DHICA and their quinones. Regulation of melanogenesis is achieved by physical and biochemical factors. The article presents the intracellular signaling pathways: cAMP/PKA/CREB/MITF cascade, MAP kinases cascade, PLC/DAG/PKCβ cascade and NO/cGMP/PKG cascade, which are involved in the regulation of expression and activity of the melanogenesis-related proteins by ultraviolet radiation and endogenous agents (cytokines, hormones. Activity of the key melanogenic enzyme, tyrosinase, is also affected by pH and temperature. Many pharmacologically active substances are able to inhibit or stimulate melanin biosynthesis, as evidenced by in vitro studies on cultured pigment cells.

  3. Mast cell chemotaxis – Chemoattractants and signaling pathways

    Directory of Open Access Journals (Sweden)

    Ivana eHalova

    2012-05-01

    Full Text Available Migration of mast cells is essential for their recruitment within target tissues where they play an important role in innate and adaptive immune responses. These processes rely on the ability of mast cells to recognize appropriate chemotactic stimuli and react to them by a chemotactic response. Another level of intercellular communication is attained by production of chemoattractants by activated mast cells, which results in accumulation of mast cells and other hematopoietic cells at the sites of inflammation. Mast cells express numerous surface receptors for various ligands with properties of potent chemoattractants. They include the stem cell factor recognized by c-Kit, antigen, which binds to immunoglobulin E (IgE anchored to the high affinity IgE receptor (FcRI, highly cytokinergic IgE recognized by FcRI, lipid mediator sphingosine-1-phosphate (S1P, which binds to G-protein-coupled receptors (GPCRs. Other large groups of chemoattractants are eicosanoids [prostaglandin E2 and D2, leukotriene (LT B4, LTD4 and LTC4, and others] and chemokines (CC, CXC, C and CX3X, which also bind to various GPCRs. Further noteworthy chemoattractants are isoforms of transforming growth factor (TGF , which are sensitively recognized by TGF- serine/threonine type I and II  receptors, adenosine, C1q, C3a, and C5a components of the complement, 5-hydroxytryptamine, neuroendocrine peptide catestatin, interleukin-6, tumor necrosis factor- and others. Here we discuss the major types of chemoattractants recognized by mast cells, their target receptors, as well as signaling pathways they utilize. We also briefly deal with methods used for studies of mast cell chemotaxis and with ways of how these studies profited from the results obtained in other cellular systems.

  4. Porcine Circovirus-Like Virus P1 Inhibits Wnt Signaling Pathway in Vivo and in Vitro.

    Science.gov (United States)

    Zhu, Xuejiao; Wen, Libin; Sheng, Shaoyang; Wang, Wei; Xiao, Qi; Qu, Meng; Hu, Yiyi; Liu, Chuanmin; He, Kongwang

    2018-01-01

    Porcine circovirus-like virus P1 is an important pathogen of the current pig industry, the infection mechanism is not entirely clear. Wnt signaling pathway plays an important role in the growth of young animals and infection of some viruses. This study was designed to demonstrate the effects of P1 infection on the Wnt signaling pathway. In vivo experiments, we demonstrated the down-regulatory effects of P1 infection in piglets and mice on the downstream components expression levels of Wnt signaling pathway, and the effects of Wnt signaling pathway activation on the pathogenesis of P1. In vitro studies, we found P1 infection down-regulated protein level of β-catenin and mRNA level of mmp2, prevented the β-catenin from entering into nucleus, abolished the TCF/LEF promoter activity, proved that P1 could inhibit the activation of Wnt signaling pathway in vitro . Finally, we found that VP1 of P1 virus also had the inhibitory effects on Wnt signaling pathway in vitro , elucidated the mechanism of P1's inhibitory effects on the Wnt signaling pathway and offered the possibility that the suppression of Wnt signaling pathway was involved in the post-weaning multisystemic wasting syndrome (PMWS), laying a foundation for elucidating the pathogenesis of P1.

  5. Porcine Circovirus-Like Virus P1 Inhibits Wnt Signaling Pathway in Vivo and in Vitro

    Directory of Open Access Journals (Sweden)

    Xuejiao Zhu

    2018-03-01

    Full Text Available Porcine circovirus-like virus P1 is an important pathogen of the current pig industry, the infection mechanism is not entirely clear. Wnt signaling pathway plays an important role in the growth of young animals and infection of some viruses. This study was designed to demonstrate the effects of P1 infection on the Wnt signaling pathway. In vivo experiments, we demonstrated the down-regulatory effects of P1 infection in piglets and mice on the downstream components expression levels of Wnt signaling pathway, and the effects of Wnt signaling pathway activation on the pathogenesis of P1. In vitro studies, we found P1 infection down-regulated protein level of β-catenin and mRNA level of mmp2, prevented the β-catenin from entering into nucleus, abolished the TCF/LEF promoter activity, proved that P1 could inhibit the activation of Wnt signaling pathway in vitro. Finally, we found that VP1 of P1 virus also had the inhibitory effects on Wnt signaling pathway in vitro, elucidated the mechanism of P1’s inhibitory effects on the Wnt signaling pathway and offered the possibility that the suppression of Wnt signaling pathway was involved in the post-weaning multisystemic wasting syndrome (PMWS, laying a foundation for elucidating the pathogenesis of P1.

  6. Exercise-Induced Hypertrophic and Oxidative Signaling Pathways and Myokine Expression in Fast Muscle of Adult Zebrafish

    Directory of Open Access Journals (Sweden)

    Mireia Rovira

    2017-12-01

    Full Text Available Skeletal muscle is a plastic tissue that undergoes cellular and metabolic adaptations under conditions of increased contractile activity such as exercise. Using adult zebrafish as an exercise model, we previously demonstrated that swimming training stimulates hypertrophy and vascularization of fast muscle fibers, consistent with the known muscle growth-promoting effects of exercise and with the resulting increased aerobic capacity of this tissue. Here we investigated the potential involvement of factors and signaling mechanisms that could be responsible for exercise-induced fast muscle remodeling in adult zebrafish. By subjecting zebrafish to swimming-induced exercise, we observed an increase in the activity of mammalian target of rapamycin (mTOR and Mef2 protein levels in fast muscle. We also observed an increase in the protein levels of the mitotic marker phosphorylated histone H3 that correlated with an increase in the protein expression levels of Pax7, a satellite-like cell marker. Furthermore, the activity of AMP-activated protein kinase (AMPK was also increased by exercise, in parallel with an increase in the mRNA expression levels of pgc1α and also of pparda, a β-oxidation marker. Changes in the mRNA expression levels of slow and fast myosin markers further supported the notion of an exercise-induced aerobic phenotype in zebrafish fast muscle. The mRNA expression levels of il6, il6r, apln, aplnra and aplnrb, sparc, decorin and igf1, myokines known in mammals to be produced in response to exercise and to signal through mTOR/AMPK pathways, among others, were increased in fast muscle of exercised zebrafish. These results support the notion that exercise increases skeletal muscle growth and myogenesis in adult zebrafish through the coordinated activation of the mTOR-MEF2 and AMPK-PGC1α signaling pathways. These results, coupled with altered expression of markers for oxidative metabolism and fast-to-slow fiber-type switch, also suggest

  7. Inhibition of the adrenomedullin/nitric oxide signaling pathway in early diabetic retinopathy.

    Science.gov (United States)

    Blom, Jan J; Giove, Thomas J; Favazza, Tara L; Akula, James D; Eldred, William D

    2011-06-01

    The nitric oxide (NO) signaling pathway is integrally involved in visual processing and changes in the NO pathway are measurable in eyes of diabetic patients. The small peptide adrenomedullin (ADM) can activate a signaling pathway to increase the enzyme activity of neuronal nitric oxide synthase (nNOS). ADM levels are elevated in eyes of diabetic patients and therefore, ADM may play a role in the pathology of diabetic retinopathy. The goal of this research was to test the effects of inhibiting the ADM/NO signaling pathway in early diabetic retinopathy. Inhibition of this pathway decreased NO production in high-glucose retinal cultures. Treating diabetic mice with the PKC β inhibitor ruboxistaurin for 5 weeks lowered ADM mRNA levels and ADM-like immunoreactivity and preserved retinal function as assessed by electroretinography. The results of this study indicate that inhibiting the ADM/NO signaling pathway prevents neuronal pathology and functional losses in early diabetic retinopathy.

  8. The effect of caffeine on skeletal muscle anabolic signaling and hypertrophy.

    Science.gov (United States)

    Moore, Timothy M; Mortensen, Xavier M; Ashby, Conrad K; Harris, Alexander M; Kump, Karson J; Laird, David W; Adams, Aaron J; Bray, Jeremy K; Chen, Ting; Thomson, David M

    2017-06-01

    Caffeine is a widely consumed stimulant with the potential to enhance physical performance through multiple mechanisms. However, recent in vitro findings have suggested that caffeine may block skeletal muscle anabolic signaling through AMP-activated protein kinase (AMPK)-mediated inhibition of mechanistic target of rapamycin (mTOR) signaling pathway. This could negatively affect protein synthesis and the capacity for muscle growth. The primary purpose of this study was to assess the effect of caffeine on in vivo AMPK and mTOR pathway signaling, protein synthesis, and muscle growth. In cultured C2C12 muscle cells, physiological levels of caffeine failed to impact mTOR activation or myoblast proliferation or differentiation. We found that caffeine administration to mice did not significantly enhance the phosphorylation of AMPK or inhibit signaling proteins downstream of mTOR (p70S6k, S6, or 4EBP1) or protein synthesis after a bout of electrically stimulated contractions. Skeletal muscle-specific knockout of LKB1, the primary AMPK activator in skeletal muscle, on the other hand, eliminated AMPK activation by contractions and enhanced S6k, S6, and 4EBP1 activation before and after contractions. In rats, the addition of caffeine did not affect plantaris hypertrophy induced by the tenotomy of the gastrocnemius and soleus muscles. In conclusion, caffeine administration does not impair skeletal muscle load-induced mTOR signaling, protein synthesis, or muscle hypertrophy.

  9. The role of the Hedgehog signaling pathway in cancer: A comprehensive review

    Directory of Open Access Journals (Sweden)

    Ana Marija Skoda

    2018-02-01

    Full Text Available The Hedgehog (Hh signaling pathway was first identified in the common fruit fly. It is a highly conserved evolutionary pathway of signal transmission from the cell membrane to the nucleus. The Hh signaling pathway plays an important role in the embryonic development. It exerts its biological effects through a signaling cascade that culminates in a change of balance between activator and repressor forms of glioma-associated oncogene (Gli transcription factors. The components of the Hh signaling pathway involved in the signaling transfer to the Gli transcription factors include Hedgehog ligands (Sonic Hh [SHh], Indian Hh [IHh], and Desert Hh [DHh], Patched receptor (Ptch1, Ptch2, Smoothened receptor (Smo, Suppressor of fused homolog (Sufu, kinesin protein Kif7, protein kinase A (PKA, and cyclic adenosine monophosphate (cAMP. The activator form of Gli travels to the nucleus and stimulates the transcription of the target genes by binding to their promoters. The main target genes of the Hh signaling pathway are PTCH1, PTCH2, and GLI1. Deregulation of the Hh signaling pathway is associated with developmental anomalies and cancer, including Gorlin syndrome, and sporadic cancers, such as basal cell carcinoma, medulloblastoma, pancreatic, breast, colon, ovarian, and small-cell lung carcinomas. The aberrant activation of the Hh signaling pathway is caused by mutations in the related genes (ligand-independent signaling or by the excessive expression of the Hh signaling molecules (ligand-dependent signaling – autocrine or paracrine. Several Hh signaling pathway inhibitors, such as vismodegib and sonidegib, have been developed for cancer treatment. These drugs are regarded as promising cancer therapies, especially for patients with refractory/advanced cancers.

  10. Signaling pathways activation profiles make better markers of cancer than expression of individual genes

    OpenAIRE

    Borisov, Nikolay M.; Terekhanova, Nadezhda V.; Aliper, Alexander M.; Venkova, Larisa S.; Smirnov, Philip Yu; Roumiantsev, Sergey; Korzinkin, Mikhail B.; Zhavoronkov, Alex A.; Buzdin, Anton A.

    2014-01-01

    Identification of reliable and accurate molecular markers remains one of the major challenges of contemporary biomedicine. We developed a new bioinformatic technique termed OncoFinder that for the first time enables to quantatively measure activation of intracellular signaling pathways basing on transcriptomic data. Signaling pathways regulate all major cellular events in health and disease. Here, we showed that the Pathway Activation Strength (PAS) value itself may serve as the biomarker for...

  11. DMPD: Signal transduction pathways mediated by the interaction of CpG DNA withToll-like receptor 9. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 14751759 Signal transduction pathways mediated by the interaction of CpG DNA withTo...;16(1):17-22. (.png) (.svg) (.html) (.csml) Show Signal transduction pathways mediated by the interaction of... CpG DNA withToll-like receptor 9. PubmedID 14751759 Title Signal transduction pathways media

  12. Signaling Pathways Related to Protein Synthesis and Amino Acid Concentration in Pig Skeletal Muscles Depend on the Dietary Protein Level, Genotype and Developmental Stages.

    Directory of Open Access Journals (Sweden)

    Yingying Liu

    Full Text Available Muscle growth is regulated by the homeostatic balance of the biosynthesis and degradation of muscle proteins. To elucidate the molecular interactions among diet, pig genotype, and physiological stage, we examined the effect of dietary protein concentration, pig genotype, and physiological stages on amino acid (AA pools, protein deposition, and related signaling pathways in different types of skeletal muscles. The study used 48 Landrace pigs and 48 pure-bred Bama mini-pigs assigned to each of 2 dietary treatments: lower/GB (Chinese conventional diet- or higher/NRC (National Research Council-protein diet. Diets were fed from 5 weeks of age to respective market weights of each genotype. Samples of biceps femoris muscle (BFM, type I and longissimus dorsi muscle (LDM, type II were collected at nursery, growing, and finishing phases according to the physiological stage of each genotype, to determine the AA concentrations, mRNA levels for growth-related genes in muscles, and protein abundances of mechanistic target of rapamycin (mTOR signaling pathway. Our data showed that the concentrations of most AAs in LDM and BFM of pigs increased (P<0.05 gradually with increasing age. Bama mini-pigs had generally higher (P<0.05 muscle concentrations of flavor-related AA, including Met, Phe, Tyr, Pro, and Ser, compared with Landrace pigs. The mRNA levels for myogenic determining factor, myogenin, myocyte-specific enhancer binding factor 2 A, and myostatin of Bama mini-pigs were higher (P<0.05 than those of Landrace pigs, while total and phosphorylated protein levels for protein kinase B, mTOR, and p70 ribosomal protein S6 kinases (p70S6K, and ratios of p-mTOR/mTOR, p-AKT/AKT, and p-p70S6K/p70S6K were lower (P<0.05. There was a significant pig genotype-dependent effect of dietary protein on the levels for mTOR and p70S6K. When compared with the higher protein-NRC diet, the lower protein-GB diet increased (P<0.05 the levels for mTOR and p70S6K in Bama mini-pigs, but

  13. Piperlongumine induces apoptosis and autophagy in leukemic cells through targeting the PI3K/Akt/mTOR and p38 signaling pathways.

    Science.gov (United States)

    Wang, Hongfei; Wang, Yongqiang; Gao, Hongmei; Wang, Bing; Dou, Lin; Li, Yin

    2018-02-01

    Piperlongumine is an alkaloid compound extracted from Piper longum L. It is a chemical substance with various pharmacological effects and medicinal value, including anti-tumor, lipid metabolism regulatory, antiplatelet aggregation and analgesic properties. The present study aimed to understand whether piperlongumine induces the apoptosis and autophagy of leukemic cells, and to identify the mechanism involved. Cell viability and autophagy were detected using MTT, phenazine methyl sulfate and trypan blue exclusion assays. The apoptosis rate was calculated using flow cytometry. The protein expression levels of microtubule-associated protein 1A/1B-light chain 3, Akt and mechanistic target of rapamycin (mTOR) were measured using western blotting. The cell growth of leukemic cells was completely inhibited following treatment with piperlongumine, and marked apoptosis was also induced. Dead cells as a result of autophagy were stained using immunofluorescence and observed under a light microscope. Phosphoinositide 3-kinase (PI3K)/Akt/mTOR signaling was suppressed by treatment with piperlongumine, while p38 signaling and caspase-3 activity were induced by treatment with piperlongumine. It was concluded that piperlongumine induces apoptosis and autophagy in leukemic cells through targeting the PI3K/Akt/mTOR and p38 signaling pathways.

  14. Roquin Suppresses the PI3K-mTOR Signaling Pathway to Inhibit T Helper Cell Differentiation and Conversion of Treg to Tfr Cells.

    Science.gov (United States)

    Essig, Katharina; Hu, Desheng; Guimaraes, Joao C; Alterauge, Dominik; Edelmann, Stephanie; Raj, Timsse; Kranich, Jan; Behrens, Gesine; Heiseke, Alexander; Floess, Stefan; Klein, Juliane; Maiser, Andreas; Marschall, Susan; Hrabĕ de Angelis, Martin; Leonhardt, Heinrich; Calkhoven, Cornelis F; Noessner, Elfriede; Brocker, Thomas; Huehn, Jochen; Krug, Anne B; Zavolan, Mihaela; Baumjohann, Dirk; Heissmeyer, Vigo

    2017-12-19

    Roquin proteins preclude spontaneous T cell activation and aberrant differentiation of T follicular helper (Tfh) or T helper 17 (Th17) cells. Here we showed that deletion of Roquin-encoding alleles specifically in regulatory T (Treg) cells also caused the activation of conventional T cells. Roquin-deficient Treg cells downregulated CD25, acquired a follicular Treg (Tfr) cell phenotype, and suppressed germinal center reactions but could not protect from colitis. Roquin inhibited the PI3K-mTOR signaling pathway by upregulation of Pten through interfering with miR-17∼92 binding to an overlapping cis-element in the Pten 3' UTR, and downregulated the Foxo1-specific E3 ubiquitin ligase Itch. Loss of Roquin enhanced Akt-mTOR signaling and protein synthesis, whereas inhibition of PI3K or mTOR in Roquin-deficient T cells corrected enhanced Tfh and Th17 or reduced iTreg cell differentiation. Thereby, Roquin-mediated control of PI3K-mTOR signaling prevents autoimmunity by restraining activation and differentiation of conventional T cells and specialization of Treg cells. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Dysplasia and overgrowth. Magnetic resonance imaging of pediatric brain abnormalities secondary to alterations in the mechanistic target of rapamycin pathway

    Energy Technology Data Exchange (ETDEWEB)

    Shrot, Shai [Johns Hopkins University School of Medicine, Division of Pediatric Radiology and Pediatric Neuroradiology, Russell H. Morgan Department of Radiology and Radiological Science, Baltimore, MD (United States); Sheba Medical Center, Department of Diagnostic Imaging, Ramat-Gan (Israel); Hwang, Misun; Huisman, Thierry A.G.M.; Soares, Bruno P. [Johns Hopkins University School of Medicine, Division of Pediatric Radiology and Pediatric Neuroradiology, Russell H. Morgan Department of Radiology and Radiological Science, Baltimore, MD (United States); Stafstrom, Carl E. [Johns Hopkins University School of Medicine, Division of Pediatric Neurology, Department of Neurology, Baltimore, MD (United States)

    2018-02-15

    The current classification of malformations of cortical development is based on the type of disrupted embryological process (cell proliferation, migration, or cortical organization/post-migrational development) and the resulting morphological anomalous pattern of findings. An ideal classification would include knowledge of biological pathways. It has recently been demonstrated that alterations affecting the mechanistic target of rapamycin (mTOR) signaling pathway result in diverse abnormalities such as dysplastic megalencephaly, hemimegalencephaly, ganglioglioma, dysplastic cerebellar gangliocytoma, focal cortical dysplasia type IIb, and brain lesions associated with tuberous sclerosis. We review the neuroimaging findings in brain abnormalities related to alterations in the mTOR pathway, following the emerging trend from morphology towards genetics in the classification of malformations of cortical development. This approach improves the understanding of anomalous brain development and allows precise diagnosis and potentially targeted therapies that may regulate mTOR pathway function. (orig.)

  16. Dysplasia and overgrowth. Magnetic resonance imaging of pediatric brain abnormalities secondary to alterations in the mechanistic target of rapamycin pathway

    International Nuclear Information System (INIS)

    Shrot, Shai; Hwang, Misun; Huisman, Thierry A.G.M.; Soares, Bruno P.; Stafstrom, Carl E.

    2018-01-01

    The current classification of malformations of cortical development is based on the type of disrupted embryological process (cell proliferation, migration, or cortical organization/post-migrational development) and the resulting morphological anomalous pattern of findings. An ideal classification would include knowledge of biological pathways. It has recently been demonstrated that alterations affecting the mechanistic target of rapamycin (mTOR) signaling pathway result in diverse abnormalities such as dysplastic megalencephaly, hemimegalencephaly, ganglioglioma, dysplastic cerebellar gangliocytoma, focal cortical dysplasia type IIb, and brain lesions associated with tuberous sclerosis. We review the neuroimaging findings in brain abnormalities related to alterations in the mTOR pathway, following the emerging trend from morphology towards genetics in the classification of malformations of cortical development. This approach improves the understanding of anomalous brain development and allows precise diagnosis and potentially targeted therapies that may regulate mTOR pathway function. (orig.)

  17. Cross-regulation of signaling pathways: An example of nuclear hormone receptors and the canonical Wnt pathway

    Energy Technology Data Exchange (ETDEWEB)

    Beildeck, Marcy E. [Lombardi Comprehensive Cancer Center, Georgetown University, 3970 Reservoir Road, NW, Washington, DC 20057 (United States); Gelmann, Edward P. [Columbia University, Department of Medicine, New York, NY (United States); Byers, Stephen W., E-mail: byerss@georgetown.edu [Lombardi Comprehensive Cancer Center, Georgetown University, 3970 Reservoir Road, NW, Washington, DC 20057 (United States)

    2010-07-01

    Predicting the potential physiological outcome(s) of any given molecular pathway is complex because of cross-talk with other pathways. This is particularly evident in the case of the nuclear hormone receptor and canonical Wnt pathways, which regulate cell growth and proliferation, differentiation, apoptosis, and metastatic potential in numerous tissues. These pathways are known to intersect at many levels: in the intracellular space, at the membrane, in the cytoplasm, and within the nucleus. The outcomes of these interactions are important in the control of stem cell differentiation and maintenance, feedback loops, and regulating oncogenic potential. The aim of this review is to demonstrate the importance of considering pathway cross-talk when predicting functional outcomes of signaling, using nuclear hormone receptor/canonical Wnt pathway cross-talk as an example.

  18. Cross-regulation of signaling pathways: An example of nuclear hormone receptors and the canonical Wnt pathway

    International Nuclear Information System (INIS)

    Beildeck, Marcy E.; Gelmann, Edward P.; Byers, Stephen W.

    2010-01-01

    Predicting the potential physiological outcome(s) of any given molecular pathway is complex because of cross-talk with other pathways. This is particularly evident in the case of the nuclear hormone receptor and canonical Wnt pathways, which regulate cell growth and proliferation, differentiation, apoptosis, and metastatic potential in numerous tissues. These pathways are known to intersect at many levels: in the intracellular space, at the membrane, in the cytoplasm, and within the nucleus. The outcomes of these interactions are important in the control of stem cell differentiation and maintenance, feedback loops, and regulating oncogenic potential. The aim of this review is to demonstrate the importance of considering pathway cross-talk when predicting functional outcomes of signaling, using nuclear hormone receptor/canonical Wnt pathway cross-talk as an example.

  19. Unkempt is negatively regulated by mTOR and uncouples neuronal differentiation from growth control.

    Directory of Open Access Journals (Sweden)

    Amélie Avet-Rochex

    2014-09-01

    Full Text Available Neuronal differentiation is exquisitely controlled both spatially and temporally during nervous system development. Defects in the spatiotemporal control of neurogenesis cause incorrect formation of neural networks and lead to neurological disorders such as epilepsy and autism. The mTOR kinase integrates signals from mitogens, nutrients and energy levels to regulate growth, autophagy and metabolism. We previously identified the insulin receptor (InR/mTOR pathway as a critical regulator of the timing of neuronal differentiation in the Drosophila melanogaster eye. Subsequently, this pathway has been shown to play a conserved role in regulating neurogenesis in vertebrates. However, the factors that mediate the neurogenic role of this pathway are completely unknown. To identify downstream effectors of the InR/mTOR pathway we screened transcriptional targets of mTOR for neuronal differentiation phenotypes in photoreceptor neurons. We identified the conserved gene unkempt (unk, which encodes a zinc finger/RING domain containing protein, as a negative regulator of the timing of photoreceptor differentiation. Loss of unk phenocopies InR/mTOR pathway activation and unk acts downstream of this pathway to regulate neurogenesis. In contrast to InR/mTOR signalling, unk does not regulate growth. unk therefore uncouples the role of the InR/mTOR pathway in neurogenesis from its role in growth control. We also identified the gene headcase (hdc as a second downstream regulator of the InR/mTOR pathway controlling the timing of neurogenesis. Unk forms a complex with Hdc, and Hdc expression is regulated by unk and InR/mTOR signalling. Co-overexpression of unk and hdc completely suppresses the precocious neuronal differentiation phenotype caused by loss of Tsc1. Thus, Unk and Hdc are the first neurogenic components of the InR/mTOR pathway to be identified. Finally, we show that Unkempt-like is expressed in the developing mouse retina and in neural stem

  20. Identification of a novel Gnao-mediated alternate olfactory signaling pathway in murine OSNs

    Directory of Open Access Journals (Sweden)

    Paul eScholz

    2016-03-01

    Full Text Available It is generally agreed that in olfactory sensory neurons (OSNs, the binding of odorant molecules to their specific olfactory receptor (OR triggers a cAMP-dependent signaling cascade, activating cyclic-nucleotide gated (CNG channels. However, considerable controversy dating back more than 20 years has surrounded the question of whether alternate signaling plays a role in mammalian olfactory transduction. In this study, we demonstrate a specific alternate signaling pathway in Olfr73-expressing OSNs. Methylisoeugenol (MIEG and at least one other known weak Olfr73 agonist (Raspberry Ketone trigger a signaling cascade independent from the canonical pathway, leading to the depolarization of the cell. Interestingly, this pathway is mediated by Gnao activation, leading to Cl- efflux; however, the activation of adenylyl cyclase III (ACIII, the recruitment of Ca2+ from extra-or intracellular stores, and phosphatidylinositol 3-kinase-dependent signaling (PI signaling are not involved. Furthermore, we demonstrated that our newly identified pathway coexists with the canonical olfactory cAMP pathway in the same OSN and can be triggered by the same OR in a ligand-selective manner. We suggest that this pathway might reflect a mechanism for odor recognition predominantly used in early developmental stages before olfactory cAMP signaling is fully developed. Taken together, our findings support the existence of at least one odor-induced alternate signal transduction pathway in native OSNs mediated by Olfr73 in a ligand-selective manner.

  1. Interactions among oscillatory pathways in NF-kappa B signaling

    Directory of Open Access Journals (Sweden)

    White Michael RH

    2011-02-01

    Full Text Available Abstract Background Sustained stimulation with tumour necrosis factor alpha (TNF-alpha induces substantial oscillations—observed at both the single cell and population levels—in the nuclear factor kappa B (NF-kappa B system. Although the mechanism has not yet been elucidated fully, a core system has been identified consisting of a negative feedback loop involving NF-kappa B (RelA:p50 hetero-dimer and its inhibitor I-kappa B-alpha. Many authors have suggested that this core oscillator should couple to other oscillatory pathways. Results First we analyse single-cell data from experiments in which the NF-kappa B system is forced by short trains of strong pulses of TNF-alpha. Power spectra of the ratio of nuclear-to-cytoplasmic concentration of NF-kappa B suggest that the cells' responses are entrained by the pulsing frequency. Using a recent model of the NF-kappa B system due to Caroline Horton, we carried out extensive numerical simulations to analyze the response frequencies induced by trains of pulses of TNF-alpha stimulation having a wide range of frequencies and amplitudes. These studies suggest that for sufficiently weak stimulation, various nonlinear resonances should be observable. To explore further the possibility of probing alternative feedback mechanisms, we also coupled the model to sinusoidal signals with a wide range of strengths and frequencies. Our results show that, at least in simulation, frequencies other than those of the forcing and the main NF-kappa B oscillator can be excited via sub- and superharmonic resonance, producing quasiperiodic and even chaotic dynamics. Conclusions Our numerical results suggest that the entrainment phenomena observed in pulse-stimulated experiments is a consequence of the high intensity of the stimulation. Computational studies based on current models suggest that resonant interactions between periodic pulsatile forcing and the system's natural frequencies may become evident for sufficiently

  2. Aberrant Wnt signaling pathway in medial temporal lobe structures of Alzheimer's disease

    DEFF Research Database (Denmark)

    Riise, Jesper; Plath, Niels; Pakkenberg, Bente

    2015-01-01

    alterations of the intracellular Wnt pathway signaling components β-catenin, Gsk3β and Tcf7l1/Tcf3 and the phosphorylation state of β-catenin and Gsk3β in the hippocampus suggestive of a link between AD and aberrant canonical activity. Alterations in Gsk3β co-appeared with hippocampal kinase...... on isolated Wnt pathway components. Here, we provide the first comprehensive pathway-focused evaluation of the Wnt pathway in the entorhinal cortex and hippocampus of AD brains. Our data demonstrate altered Wnt pathway gene expression at all levels of the pathway in both medial temporal lobe regions...

  3. The node-weighted Steiner tree approach to identify elements of cancer-related signaling pathways.

    Science.gov (United States)

    Sun, Yahui; Ma, Chenkai; Halgamuge, Saman

    2017-12-28

    Cancer constitutes a momentous health burden in our society. Critical information on cancer may be hidden in its signaling pathways. However, even though a large amount of money has been spent on cancer research, some critical information on cancer-related signaling pathways still remains elusive. Hence, new works towards a complete understanding of cancer-related signaling pathways will greatly benefit the prevention, diagnosis, and treatment of cancer. We propose the node-weighted Steiner tree approach to identify important elements of cancer-related signaling pathways at the level of proteins. This new approach has advantages over previous approaches since it is fast in processing large protein-protein interaction networks. We apply this new approach to identify important elements of two well-known cancer-related signaling pathways: PI3K/Akt and MAPK. First, we generate a node-weighted protein-protein interaction network using protein and signaling pathway data. Second, we modify and use two preprocessing techniques and a state-of-the-art Steiner tree algorithm to identify a subnetwork in the generated network. Third, we propose two new metrics to select important elements from this subnetwork. On a commonly used personal computer, this new approach takes less than 2 s to identify the important elements of PI3K/Akt and MAPK signaling pathways in a large node-weighted protein-protein interaction network with 16,843 vertices and 1,736,922 edges. We further analyze and demonstrate the significance of these identified elements to cancer signal transduction by exploring previously reported experimental evidences. Our node-weighted Steiner tree approach is shown to be both fast and effective to identify important elements of cancer-related signaling pathways. Furthermore, it may provide new perspectives into the identification of signaling pathways for other human diseases.

  4. Inhibitors of mTOR

    NARCIS (Netherlands)

    Klümpen, Heinz-Josef; Beijnen, Jos H.; Gurney, Howard; Schellens, Jan H. M.

    2010-01-01

    Inhibitors of mammalian target of rapamycin (mTOR) have been approved for the treatment of renal cell carcinoma and appear to have a role in the treatment of other malignancies. The primary objective of this drug review is to provide pharmacokinetic and dynamic properties of the commonly used drugs

  5. PI3K-Akt signaling activates mTOR-mediated epileptogenesis in organotypic hippocampal culture model of post-traumatic epilepsy.

    Science.gov (United States)

    Berdichevsky, Yevgeny; Dryer, Alexandra M; Saponjian, Yero; Mahoney, Mark M; Pimentel, Corrin A; Lucini, Corrina A; Usenovic, Marija; Staley, Kevin J

    2013-05-22

    mTOR is activated in epilepsy, but the mechanisms of mTOR activation in post-traumatic epileptogenesis are unknown. It is also not clear whether mTOR inhibition has an anti-epileptogenic, or merely anticonvulsive effect. The rat hippocampal organotypic culture model of post-traumatic epilepsy was used to study the effects of long-term (four weeks) inhibition of signaling pathways that interact with mTOR. Ictal activity was quantified by measurement of lactate production and electrical recordings, and cell death was quantified with lactate dehydrogenase (LDH) release measurements and Nissl-stained neuron counts. Lactate and LDH measurements were well correlated with electrographic activity and neuron counts, respectively. Inhibition of PI3K and Akt prevented activation of mTOR, and was as effective as inhibition of mTOR in reducing ictal activity and cell death. A dual inhibitor of PI3K and mTOR, NVP-BEZ235, was also effective. Inhibition of mTOR with rapamycin reduced axon sprouting. Late start of rapamycin treatment was effective in reducing epileptic activity and cell death, while early termination of rapamycin treatment did not result in increased epileptic activity or cell death. The conclusions of the study are as follows: (1) the organotypic hippocampal culture model of post-traumatic epilepsy comprises a rapid assay of anti-epileptogenic and neuroprotective activities and, in this model (2) mTOR activation depends on PI3K-Akt signaling, and (3) transient inhibition of mTOR has sustained effects on epilepsy.

  6. Comparative Analysis of Muscle Hypertrophy Models Reveals Divergent Gene Transcription Profiles and Points to Translational Regulation of Muscle Growth through Increased mTOR Signaling

    Directory of Open Access Journals (Sweden)

    Marcelo G. Pereira

    2017-12-01

    Full Text Available Skeletal muscle mass is a result of the balance between protein breakdown and protein synthesis. It has been shown that multiple conditions of muscle atrophy are characterized by the common regulation of a specific set of genes, termed atrogenes. It is not known whether various models of muscle hypertrophy are similarly regulated by a common transcriptional program. Here, we characterized gene expression changes in three different conditions of muscle growth, examining each condition during acute and chronic phases. Specifically, we compared the transcriptome of Extensor Digitorum Longus (EDL muscles collected (1 during the rapid phase of postnatal growth at 2 and 4 weeks of age, (2 24 h or 3 weeks after constitutive activation of AKT, and (3 24 h or 3 weeks after overload hypertrophy caused by tenotomy of the Tibialis Anterior muscle. We observed an important overlap between significantly regulated genes when comparing each single condition at the two different timepoints. Furthermore, examining the transcriptional changes occurring 24 h after a hypertrophic stimulus, we identify an important role for genes linked to a stress response, despite the absence of muscle damage in the AKT model. However, when we compared all different growth conditions, we did not find a common transcriptional fingerprint. On the other hand, all conditions showed a marked increase in mTORC1 signaling and increased ribosome biogenesis, suggesting that muscle growth is characterized more by translational, than transcriptional regulation.

  7. Optimal structural inference of signaling pathways from unordered and overlapping gene sets.

    Science.gov (United States)

    Acharya, Lipi R; Judeh, Thair; Wang, Guangdi; Zhu, Dongxiao

    2012-02-15

    A plethora of bioinformatics analysis has led to the discovery of numerous gene sets, which can be interpreted as discrete measurements emitted from latent signaling pathways. Their potential to infer signaling pathway structures, however, has not been sufficiently exploited. Existing methods accommodating discrete data do not explicitly consider signal cascading mechanisms that characterize a signaling pathway. Novel computational methods are thus needed to fully utilize gene sets and broaden the scope from focusing only on pairwise interactions to the more general cascading events in the inference of signaling pathway structures. We propose a gene set based simulated annealing (SA) algorithm for the reconstruction of signaling pathway structures. A signaling pathway structure is a directed graph containing up to a few hundred nodes and many overlapping signal cascades, where each cascade represents a chain of molecular interactions from the cell surface to the nucleus. Gene sets in our context refer to discrete sets of genes participating in signal cascades, the basic building blocks of a signaling pathway, with no prior information about gene orderings in the cascades. From a compendium of gene sets related to a pathway, SA aims to search for signal cascades that characterize the optimal signaling pathway structure. In the search process, the extent of overlap among signal cascades is used to measure the optimality of a structure. Throughout, we treat gene sets as random samples from a first-order Markov chain model. We evaluated the performance of SA in three case studies. In the first study conducted on 83 KEGG pathways, SA demonstrated a significantly better performance than Bayesian network methods. Since both SA and Bayesian network methods accommodate discrete data, use a 'search and score' network learning strategy and output a directed network, they can be compared in terms of performance and computational time. In the second study, we compared SA and

  8. The emerging role of m-TOR up-regulation in brain Astrocytoma.

    Science.gov (United States)

    Ryskalin, Larisa; Limanaqi, Fiona; Biagioni, Francesca; Frati, Alessandro; Esposito, Vincenzo; Calierno, Maria Teresa; Lenzi, Paola; Fornai, Francesco

    2017-05-01

    The present manuscript is an overview of various effects of mTOR up-regulation in astrocytoma with an emphasis on its deleterious effects on the proliferation of Glioblastoma Multiforme. The manuscript reports consistent evidence indicating the occurrence of mTOR up-regulation both in experimental and human astrocytoma. The grading of human astrocytoma is discussed in relationship with mTOR up-regulation. In the second part of the manuscript, the biochemical pathways under the influence of mTOR are translated to cell phenotypes which are generated by mTOR up-regulation and reverted by its inhibition. A special section is dedicated to the prominent role of autophagy in mediating the effects of mTOR in glioblastoma. In detail, autophagy inhibition produced by mTOR up-regulation determines the fate of cancer stem cells. On the other hand, biochemical findings disclose the remarkable effects of autophagy activators as powerful inducers of cell differentiation with a strong prevalence towards neuronal phenotypes. Thus, mTOR modulation acts on the neurobiology of glioblastoma just like it operates in vivo at the level of brain stem cell niches by altering autophagy-dependent cell differentiation. In the light of such a critical role of autophagy we analyzed the ubiquitin proteasome system. The merging between autophagy and proteasome generates a novel organelle, named autophagoproteasome which is strongly induced by mTOR inhibitors in glioblastoma cells. Remarkably, when mTOR is maximally inhibited the proteasome component selectively moves within autophagy vacuoles, thus making the proteasome activity dependent on the entry within autophagy compartment.

  9. Second messenger/signal transduction pathways in major mood disorders: moving from membrane to mechanism of action, part I: major depressive disorder.

    Science.gov (United States)

    Niciu, Mark J; Ionescu, Dawn F; Mathews, Daniel C; Richards, Erica M; Zarate, Carlos A

    2013-10-01

    The etiopathogenesis and treatment of major mood disorders have historically focused on modulation of monoaminergic (serotonin, norepinephrine, dopamine) and amino acid [γ-aminobutyric acid (GABA), glutamate] receptors at the plasma membrane. Although the activation and inhibition of these receptors acutely alter local neurotransmitter levels, their neuropsychiatric effects are not immediately observed. This time lag implicates intracellular neuroplasticity as primary in the mechanism of action of antidepressants and mood stabilizers. The modulation of intracellular second messenger/signal transduction cascades affects neurotrophic pathways that are both necessary and sufficient for monoaminergic and amino acid-based treatments. In this review, we will discuss the evidence in support of intracellular mediators in the pathophysiology and treatment of preclinical models of despair and major depressive disorder (MDD). More specifically, we will focus on the following pathways: cAMP/PKA/CREB, neurotrophin-mediated (MAPK and others), p11, Wnt/Fz/Dvl/GSK3β, and NFκB/ΔFosB. We will also discuss recent discoveries with rapidly acting antidepressants, which activate the mammalian target of rapamycin (mTOR) and release of inhibition on local translation via elongation factor stimulation. Throughout this discourse, we will highlight potential intracellular targets for therapeutic intervention. Finally, future clinical implications are discussed.

  10. Downregulation of PI3K/Akt/mTOR signaling pathway in curcumin-induced autophagy in APP/PS1 double transgenic mice.

    Science.gov (United States)

    Wang, Chen; Zhang, Xiong; Teng, Zhipeng; Zhang, Tong; Li, Yu

    2014-10-05

    Autophagy is a lysosomal degradation pathway, which is essential for cell survival, proliferation, differentiation and homeostasis. It is well known that beta-amyloid (Aβ) aggregation is one of key characteristics for Alzheimer's disease (AD), which triggers a complex pathological cascade, leading to neurodegeneration. Recent studies have shown that Aβ peptide is generated from amyloid β precursor protein (APP) during autophagic turnover of APP-rich organelles by autophagy. Aβ generation during normal autophagy is subsequently degraded by lysosomes. Curcumin, a nature plant extraction, has been reported to inhibit the generation and deposition of Aβ; however, the underlying mechanisms are not fully understood yet. In the present study, we reported that curcumin treatment not only attenuated cognitive impairment detected by Morris water maze test, but also inhibited the generation of Aβ investigated by immunohistochemistry in APP/PS1 double transgenic AD mice. Moreover, curcumin induced autophagy in the mice, evidenced by LC3 immunofluorescence analysis and western blot assays on LC3. Furthermore, we found that curcumin significantly decreased the expression of Phosphatidylinositol 3-Kinase (PI3K), phosphorylated Akt and rapamycin (mTOR) at protein levels, respectively. Taken together, our data suggests that curcumin inhibits Aβ generation and induces of autophagy by downregulating PI3K/Akt/mTOR signaling pathway, and further shows a neuroprotective effect. Meanwhile curcumin might be a candidate neuroprotective agent for AD patients treatment by inducing autophagy. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. mTOR inhibitors in urinary bladder cancer.

    Science.gov (United States)

    Pinto-Leite, R; Arantes-Rodrigues, R; Sousa, Nuno; Oliveira, P A; Santos, L

    2016-09-01

    Despite the great scientific advances that have been made in cancer treatment, there is still much to do, particularly with regard to urinary bladder cancer. Some of the drugs used in urinary bladder cancer treatment have been in use for more than 30 years and show reduced effectiveness and high recurrence rates. There have been several attempts to find new and more effective drugs, to be used alone or in combination with the drugs already in use, in order to overcome this situation.The biologically important mammalian target of rapamycin (mTOR) pathway is altered in cancer and mTOR inhibitors have raised many expectations as potentially important anticancer drugs. In this article, the authors will review the mTOR pathway and present their experiences of the use of some mTOR inhibitors, sirolimus, everolimus and temsirolimus, in isolation and in conjunction with non-mTOR inhibitors cisplatin and gemcitabine, on urinary bladder tumour cell lines. The non-muscle-invasive cell line, 5637, is the only one that exhibits a small alteration in the mTOR and AKT phosphorylation after rapalogs exposure. Also, there was a small inhibition of cell proliferation. With gemcitabine plus everolimus or temsirolimus, the results were encouraging as a more effective response was noticed with both combinations, especially in the 5637 and T24 cell lines. Cisplatin associated with everolimus or temsirolimus also gave promising results, as an antiproliferative effect was observed when the drugs were associated, in particular on the 5637 and HT1376 cell lines. Everolimus or temsirolimus in conjunction with gemcitabine or cisplatin could have an important role to play in urinary bladder cancer treatment, depending on the tumour grading.

  12. Sensitivity analysis of intracellular signaling pathway kinetics predicts targets for stem cell fate control.

    Directory of Open Access Journals (Sweden)

    Alborz Mahdavi

    2007-07-01

    Full Text Available Directing stem cell fate requires knowledge of how signaling networks integrate temporally and spatially segregated stimuli. We developed and validated a computational model of signal transducer and activator of transcription-3 (Stat3 pathway kinetics, a signaling network involved in embryonic stem cell (ESC self-renewal. Our analysis identified novel pathway responses; for example, overexpression of the receptor glycoprotein-130 results in reduced pathway activation and increased ESC differentiation. We used a systematic in silico screen to identify novel targets and protein interactions involved in Stat3 activation. Our analysis demonstrates that signaling activation and desensitization (the inability to respond to ligand restimulation is regulated by balancing the activation state of a distributed set of parameters including nuclear export of Stat3, nuclear phosphatase activity, inhibition by suppressor of cytokine signaling, and receptor trafficking. This knowledge was used to devise a temporally modulated ligand delivery strategy that maximizes signaling activation and leads to enhanced ESC self-renewal.

  13. mTOR as a Key Regulator in Maintaining Skeletal Muscle Mass

    Directory of Open Access Journals (Sweden)

    Mee-Sup Yoon

    2017-10-01

    Full Text Available Maintenance of skeletal muscle mass is regulated by the balance between anabolic and catabolic processes. Mammalian target of rapamycin (mTOR is an evolutionarily conserved serine/threonine kinase, and is known to play vital roles in protein synthesis. Recent findings have continued to refine our understanding of the function of mTOR in maintaining skeletal muscle mass. mTOR controls the anabolic and catabolic signaling of skeletal muscle mass, resulting in the modulation of muscle hypertrophy and muscle wastage. This review will highlight the fundamental role of mTOR in skeletal muscle growth by summarizing the phenotype of skeletal-specific mTOR deficiency. In addition, the evidence that mTOR is a dual regulator of anabolism and catabolism in skeletal muscle mass will be discussed. A full understanding of mTOR signaling in the maintenance of skeletal muscle mass could help to develop mTOR-targeted therapeutics to prevent muscle wasting.

  14. Role of CSL-dependent and independent Notch signaling pathways in cell apoptosis.

    Science.gov (United States)

    Zeng, Chong; Xing, Rui; Liu, Jing; Xing, Feiyue

    2016-01-01

    Apoptosis is a normally biological phenomenon in various organisms, involving complexly molecular mechanisms with a series of signaling processes. Notch signaling is found evolutionarily conserved in many species, playing a critical role in embryonic development, normal tissue homeostasis, angiogenesis and immunoregulation. The focus of this review is on currently novel advances about roles of CSL-dependent and independent Notch signaling pathways in cell apoptosis. The CSL can bind Notch intracellular domain (NIC) to act as a switch in mediating transcriptional activation or inactivation of the Notch signaling pathway downstream genes in the nucleus. It shows that CSL-dependent signaling regulates the cell apoptosis through Hes-1-PTEN-AKT-mTOR signaling, but rather the CSL-independent signaling mediates the cell apoptosis possibly via NIC-mTORC2-AKT-mTOR signaling, providing a new insight into apoptotic mechanisms.

  15. The mTOR inhibitor rapamycin has limited acute anticonvulsant effects in mice.

    Directory of Open Access Journals (Sweden)

    Adam L Hartman

    Full Text Available The mammalian target of rapamycin (mTOR pathway integrates signals from different nutrient sources, including amino acids and glucose. Compounds that inhibit mTOR kinase activity such as rapamycin and everolimus can suppress seizures in some chronic animal models and in patients with tuberous sclerosis. However, it is not known whether mTOR inhibitors exert acute anticonvulsant effects in addition to their longer term antiepileptogenic effects. To gain insights into how rapamycin suppresses seizures, we investigated the anticonvulsant activity of rapamycin using acute seizure tests in mice.Following intraperitoneal injection of rapamycin, normal four-week-old male NIH Swiss mice were evaluated for susceptibility to a battery of acute seizure tests similar to those currently used to screen potential therapeutics by the US NIH Anticonvulsant Screening Program. To assess the short term effects of rapamycin, mice were seizure tested in ≤ 6 hours of a single dose of rapamycin, and for longer term effects of rapamycin, mice were tested after 3 or more daily doses of rapamycin.The only seizure test where short-term rapamycin treatment protected mice was against tonic hindlimb extension in the MES threshold test, though this protection waned with longer rapamycin treatment. Longer term rapamycin treatment protected against kainic acid-induced seizure activity, but only at late times after seizure onset. Rapamycin was not protective in the 6 Hz or PTZ seizure tests after short or longer rapamycin treatment times. In contrast to other metabolism-based therapies that protect in acute seizure tests, rapamycin has limited acute anticonvulsant effects in normal mice.The efficacy of rapamycin as an acute anticonvulsant agent may be limited. Furthermore, the combined pattern of acute seizure test results places rapamycin in a third category distinct from both fasting and the ketogenic diet, and which is more similar to drugs acting on sodium channels.

  16. Rapidly exploring structural and dynamic properties of signaling networks using PathwayOracle

    Directory of Open Access Journals (Sweden)

    Ram Prahlad T

    2008-08-01

    Full Text Available Abstract Background In systems biology the experimentalist is presented with a selection of software for analyzing dynamic properties of signaling networks. These tools either assume that the network is in steady-state or require highly parameterized models of the network of interest. For biologists interested in assessing how signal propagates through a network under specific conditions, the first class of methods does not provide sufficiently detailed results and the second class requires models which may not be easily and accurately constructed. A tool that is able to characterize the dynamics of a signaling network using an unparameterized model of the network would allow biologists to quickly obtain insights into a signaling network's behavior. Results We introduce PathwayOracle, an integrated suite of software tools for computationally inferring and analyzing structural and dynamic properties of a signaling network. The feature which differentiates PathwayOracle from other tools is a method that can predict the response of a signaling network to various experimental conditions and stimuli using only the connectivity of the signaling network. Thus signaling models are relatively easy to build. The method allows for tracking signal flow in a network and comparison of signal flows under different experimental conditions. In addition, PathwayOracle includes tools for the enumeration and visualization of coherent and incoherent signaling paths between proteins, and for experimental analysis – loading and superimposing experimental data, such as microarray intensities, on the network model. Conclusion PathwayOracle provides an integrated environment in which both structural and dynamic analysis of a signaling network can be quickly conducted and visualized along side experimental results. By using the signaling network connectivity, analyses and predictions can be performed quickly using relatively easily constructed signaling network models

  17. Sex and hedgehog: roles of genes in the hedgehog signaling pathway in mammalian sexual differentiation.

    Science.gov (United States)

    Franco, Heather L; Yao, Humphrey H-C

    2012-01-01

    The chromosome status of the mammalian embryo initiates a multistage process of sexual development in which the bipotential reproductive system establishes itself as either male or female. These events are governed by intricate cell-cell and interorgan communication that is regulated by multiple signaling pathways. The hedgehog signaling pathway was originally identified for its key role in the development of Drosophila, but is now recognized as a critical developmental regulator in many species, including humans. In addition to its developmental roles, the hedgehog signaling pathway also modulates adult organ function, and misregulation of this pathway often leads to diseases, such as cancer. The hedgehog signaling pathway acts through its morphogenetic ligands that signal from ligand-producing cells to target cells over a specified distance. The target cells then respond in a graded manner based on the concentration of the ligands that they are exposed to. Through this unique mechanism of action, the hedgehog signaling pathway elicits cell fate determination, epithelial-mesenchymal interactions, and cellular homeostasis. Here, we review current findings on the roles of hedgehog signaling in the sexually dimorphic development of the reproductive organs with an emphasis on mammals and comparative evidence in other species.

  18. A comparative study of the molecular evolution of signalling pathway ...

    Indian Academy of Sciences (India)

    2013-08-05

    Aug 5, 2013 ... formed using DnaSP ver. 5 (Librado and Rozas 2009) from ... a context of global divergence within each phylum we exam- ined genomewide ... suggests that the overall conserved sensory signalling cas- cade members are ...

  19. Transient activation of mTOR following forced treadmill exercise in rats

    DEFF Research Database (Denmark)

    Elfving, Betina; Christensen, Tina; Ratner, Cecilia

    2013-01-01

    , while the induction of neurogenesis requires signaling through the VEGF receptor, Flk-1 (VEGFR-2). VEGF expression is believed to be regulated by two distinct mTOR (mammalian Target of Rapamycin)-containing multiprotein complexes mTORC1 and mTORC2, respectively. This study was initiated to investigate...... of mTOR was regulated after a single bout of exercise. In conclusion, the effect of treadmill exercise on the VEGF system is acute rather than chronic and there is a transient activation of mTOR. More studies are needed to understand whether this could be beneficial in the treatment of neuropsychiatric...

  20. Correlated cone noise decreases rod signal contributions to the post-receptoral pathways.

    Science.gov (United States)

    Hathibelagal, Amithavikram R; Feigl, Beatrix; Zele, Andrew J

    2018-04-01

    This study investigated how invisible extrinsic temporal white noise that correlates with the activity of one of the three [magnocellular (MC), parvocellular (PC), or koniocellular (KC)] post-receptoral pathways alters mesopic rod signaling. A four-primary photostimulator provided independent control of the rod and three cone photoreceptor excitations. The rod contributions to the three post-receptoral pathways were estimated by perceptually matching a 20% contrast rod pulse by independently varying the LMS (MC pathway), +L-M (PC pathway), and S-cone (KC pathway) excitations. We show that extrinsic cone noise caused a predominant decrease in the overall magnitude and ratio of the rod contributions to each pathway. Thus, the relative cone activity in the post-receptoral pathways determines the relative mesopic rod inputs to each pathway.

  1. The ABA-INSENSITIVE-4 (ABI4) transcription factor links redox, hormone and sugar signaling pathways.

    Science.gov (United States)

    Foyer, Christine H; Kerchev, Pavel I; Hancock, Robert D

    2012-02-01

    The cellular reduction-oxidation (redox) hub processes information from metabolism and the environment and so regulates plant growth and defense through integration with the hormone signaling network. One key pathway of redox control involves interactions with ABSCISIC ACID (ABA). Accumulating evidence suggests that the ABA-INSENSITIVE-4 (ABI4) transcription factor plays a key role in transmitting information concerning the abundance of ascorbate and hence the ability of cells to buffer oxidative challenges. ABI4 is required for the ascorbate-dependent control of growth, a process that involves enhancement of salicylic acid (SA) signaling and inhibition of jasmonic acid (JA) signaling pathways. Low redox buffering capacity reinforces SA- JA- interactions through the mediation of ABA and ABI4 to fine-tune plant growth and defense in relation to metabolic cues and environmental challenges. Moreover, ABI4-mediated pathways of sugar sensitivity are also responsive to the abundance of ascorbate, providing evidence of overlap between redox and sugar signaling pathways.

  2. Characterization of Heregulin-Stimulated Signal Transduction Pathways to the Nucleus

    National Research Council Canada - National Science Library

    Wilson, Kristin

    2000-01-01

    ... 40% of breast cancers and correlates with a poor prognosis for women with breast cancer. Mapping the molecular determinants of the heregulin/ErbB2 signaling pathway will be important in determining viable cellular targets for therapeutic intervention...

  3. Wnt signaling inhibits CTL memory programming.

    Science.gov (United States)

    Xiao, Zhengguo; Sun, Zhifeng; Smyth, Kendra; Li, Lei

    2013-12-01

    Induction of functional CTLs is one of the major goals for vaccine development and cancer therapy. Inflammatory cytokines are critical for memory CTL generation. Wnt signaling is important for CTL priming and memory formation, but its role in cytokine-driven memory CTL programming is unclear. We found that wnt signaling inhibited IL-12-driven CTL activation and memory programming. This impaired memory CTL programming was attributed to up-regulation of eomes and down-regulation of T-bet. Wnt signaling suppressed the mTOR pathway during CTL activation, which was different to its effects on other cell types. Interestingly, the impaired memory CTL programming by wnt was partially rescued by mTOR inhibitor rapamycin. In conclusion, we found that crosstalk between wnt and the IL-12 signaling inhibits T-bet and mTOR pathways and impairs memory programming which can be recovered in part by rapamycin. In addition, direct inhibition of wnt signaling during CTL activation does not affect CTL memory programming. Therefore, wnt signaling may serve as a new tool for CTL manipulation in autoimmune diseases and immune therapy for certain cancers. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. Investigation of radiation-induced multilayered signalling response of the inflammatory pathway

    International Nuclear Information System (INIS)

    Babini, G.; Ugolini, M.; Morini, J.; Baiocco, G.; Ottolenghi, A.; Mariotti, L.; Tabarelli de Fatis, P.; Liotta, M.

    2015-01-01

    Ionising radiation exposure of cells might induce the perturbation of cell functions and, in particular, the activation or inhibition of several important pathways. This perturbation can cause the deregulation of both intra- and extra-cellular signalling cascades (such as the inflammatory pathway) and alter not only the behaviour of directly exposed cells but also the neighbouring nonirradiated ones, through the so-called bystander effect. The aim of the present work was to investigate the complex nonlinear interactions between the inflammatory pathway and other strictly interlaced signalling pathways, such as Erk1/2 and Akt/PKB, focusing on the radiation-induced perturbation of such pathways in the dose range of 0 -2 Gy. The results show how radiation affects these interconnected pathways and how confounding factors, such as the change of culture medium, can hide radiation-induced perturbations. (authors)

  5. Molecular pathway profiling of T lymphocyte signal transduction pathways; Th1 and Th2 genomic fingerprints are defined by TCR and CD28-mediated signaling

    NARCIS (Netherlands)

    Smeets, Ruben L.; Fleuren, Wilco W. M.; He, Xuehui; Vink, Paul M.; Wijnands, Frank; Gorecka, Monika; Klop, Henri; Bauerschmidt, Sussane; Garritsen, Anja; Koenen, Hans J. P. M.; Joosten, Irma; Boots, Annemieke M. H.; Alkema, Wynand

    2012-01-01

    Background: T lymphocytes are orchestrators of adaptive immunity. Naive T cells may differentiate into Th1, Th2, Th17 or iTreg phenotypes, depending on environmental co-stimulatory signals. To identify genes and pathways involved in differentiation of Jurkat T cells towards Th1 and Th2 subtypes we

  6. Molecular pathway profiling of T lymphocyte signal transduction pathways; Th1 and Th2 genomic fingerprints are defined by TCR and CD28-mediated signaling.

    NARCIS (Netherlands)

    Smeets, R.L.; Fleuren, W.W.M.; He, X.; Vink, P.M.; Wijnands, F.; Gorecka, M.; Klop, H.; Bauerschmidt, S.; Garritsen, A.; Koenen, H.J.P.M.; Joosten, I.; Boots, A.M.H.; Alkema, W.

    2012-01-01

    BACKGROUND: T lymphocytes are orchestrators of adaptive immunity. Naive T cells may differentiate into Th1, Th2, Th17 or iTreg phenotypes, depending on environmental co-stimulatory signals. To identify genes and pathways involved in differentiation of Jurkat T cells towards Th1 and Th2 subtypes we

  7. Advances in the therapeutic use of mammalian target of rapamycin (mTOR) inhibitors in dermatology.

    Science.gov (United States)

    Fogel, Alexander L; Hill, Sharleen; Teng, Joyce M C

    2015-05-01

    Significant developments in the use of mammalian target of rapamycin (mTOR) inhibitors (mTORIs) as immunosuppressant and antiproliferative agents have been made. Recent advances in the understanding of the mTOR signaling pathway and its downstream effects on tumorigenesis and vascular proliferation have broadened the clinical applications of mTORIs in many challenging disorders such as tuberous sclerosis complex, pachyonychia congenita, complex vascular anomalies, and inflammatory dermatoses. Systemic mTORI therapy has shown benefits in these areas, but is associated with significant side effects that sometimes necessitate drug holidays. To mitigate the side effects of systemic mTORIs for dermatologic applications, preliminary work to assess the potential of percutaneous therapy has been performed, and the evidence suggests that percutaneous delivery of mTORIs may allow for effective long-term therapy while avoiding systemic toxicities. Additional large placebo-controlled, double-blinded, randomized studies are needed to assess the efficacy, safety, duration, and tolerability of topical treatments. The objective of this review is to provide updated information on the novel use of mTORIs in the management of many cutaneous disorders. Copyright © 2015 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.

  8. The Drosophila rolled locus encodes a MAP kinase required in the sevenless signal transduction pathway.

    OpenAIRE

    Biggs, W H; Zavitz, K H; Dickson, B; van der Straten, A; Brunner, D; Hafen, E; Zipursky, S L

    1994-01-01

    Mitogen-activated protein (MAP) kinases have been proposed to play a critical role in receptor tyrosine kinase (RTK)-mediated signal transduction pathways. Although genetic and biochemical studies of RTK pathways in Caenorhabditis elegans, Drosophila melanogaster and mammals have revealed remarkable similarities, a genetic requirement for MAP kinases in RTK signaling has not been established. During retinal development in Drosophila, the sevenless (Sev) RTK is required for development of the ...

  9. Isoflurane produces antidepressant effects and induces TrkB signaling in rodents

    DEFF Research Database (Denmark)

    Antila, Hanna; Ryazantseva, Maria; Popova, Dina

    2017-01-01

    in the learned helplessness paradigm and regulates molecular events implicated in the mechanism of action of rapid-acting antidepressant ketamine: activation of brain-derived neurotrophic factor (BDNF) receptor TrkB, facilitation of mammalian target of rapamycin (mTOR) signaling pathway and inhibition...

  10. Coupled down-regulation of mTOR and telomerase activity during fluorouracil-induced apoptosis of hepatocarcinoma Cells

    Energy Technology Data Exchange (ETDEWEB)

    Bu, Xinxin; Jia, Fengqi; Wang, Weifeng; Guo, Xianling; Wu, Mengchao; Wei, Lixin [Tumor Immunology and Gene Therapy Center, Eastern Hepatobiliary Hospital, Second Military Medical Universisty, 225 Changhai Road, Shanghai 200438 (China)

    2007-11-12

    Hepatocellular carcinoma (HCC) is the most invasive and frequently diagnosed malignancy and the second leading cause of cancer death in many regions of Asia. The PI3K/Akt/mTOR signal pathway is involved in multiple cellular functions including proliferation, differentiation, tumorigenesis, and apoptosis. Up-regulation of telomerase activity is thought to be a critical step leading to cell transformation. This study investigated changes in mTOR pathway and telomerase activity in hepatocarcinoma cell line SMMC-7721 treated with chemotherapeutic agent 5-fluorouracil (5-Fu). We detected apoptosis of hepatocarcinoma cells by TUNEL assay. Telomerase activity, hTERT transcription level and p- p70 S6k was demonstrated by the telomeric repeat amplification protocol and silver staining assay, Dual-Luciferase Reporter Assay and Western blot analysis respectively. Treating SMMC-7721 cells with 5-Fu leads to apoptosis of the cells, and reduction in telomerase activity, as well as a dramatic reduction in the activated form of p70 S6 kinase, a mTOR substrate. The 5-Fu treatment nearly abolishes transcription of hTERT (the major component of telomerase) mRNA. Treating SMMC-7721 cells with Rapamycin, a specific mTOR inhibitor, significantly reduce hTERT protein level but did not affect hTERT transcription. 5-Fu and rapamycin were synergistic in regards to down-regulation of telomerase activity in hepatocarcinoma cells. These results suggest that chemotherapeutic agent 5-Fu may down-regulate telomerase activity at both transcriptional level and PI3K/Akt/mTOR pathway-dependent post-transcriptional level to facilitate hepatocellular carcinoma cell apoptosis.

  11. Coupled down-regulation of mTOR and telomerase activity during fluorouracil-induced apoptosis of hepatocarcinoma Cells

    International Nuclear Information System (INIS)

    Bu, Xinxin; Jia, Fengqi; Wang, Weifeng; Guo, Xianling; Wu, Mengchao; Wei, Lixin

    2007-01-01

    Hepatocellular carcinoma (HCC) is the most invasive and frequently diagnosed malignancy and the second leading cause of cancer death in many regions of Asia. The PI3K/Akt/mTOR signal pathway is involved in multiple cellular functions including proliferation, differentiation, tumorigenesis, and apoptosis. Up-regulation of telomerase activity is thought to be a critical step leading to cell transformation. This study investigated changes in mTOR pathway and telomerase activity in hepatocarcinoma cell line SMMC-7721 treated with chemotherapeutic agent 5-fluorouracil (5-Fu). We detected apoptosis of hepatocarcinoma cells by TUNEL assay. Telomerase activity, hTERT transcription level and p- p70 S6k was demonstrated by the telomeric repeat amplification protocol and silver staining assay, Dual-Luciferase Reporter Assay and Western blot analysis respectively. Treating SMMC-7721 cells with 5-Fu leads to apoptosis of the cells, and reduction in telomerase activity, as well as a dramatic reduction in the activated form of p70 S6 kinase, a mTOR substrate. The 5-Fu treatment nearly abolishes transcription of hTERT (the major component of telomerase) mRNA. Treating SMMC-7721 cells with Rapamycin, a specific mTOR inhibitor, significantly reduce hTERT protein level but did not affect hTERT transcription. 5-Fu and rapamycin were synergistic in regards to down-regulation of telomerase activity in hepatocarcinoma cells. These results suggest that chemotherapeutic agent 5-Fu may down-regulate telomerase activity at both transcriptional level and PI3K/Akt/mTOR pathway-dependent post-transcriptional level to facilitate hepatocellular carcinoma cell apoptosis

  12. Coupled down-regulation of mTOR and telomerase activity during fluorouracil-induced apoptosis of hepatocarcinoma Cells

    Directory of Open Access Journals (Sweden)

    Wu Mengchao

    2007-11-01

    Full Text Available Abstract Background Hepatocellular carcinoma (HCC is the most invasive and frequently diagnosed malignancy and the second leading cause of cancer death in many regions of Asia. The PI3K/Akt/mTOR signal pathway is involved in multiple cellular functions including proliferation, differentiation, tumorigenesis, and apoptosis. Up-regulation of telomerase activity is thought to be a critical step leading to cell transformation. Methods This study investigated changes in mTOR pathway and telomerase activity in hepatocarcinoma cell line SMMC-7721 treated with chemotherapeutic agent 5-fluorouracil (5-Fu. We detected apoptosis of hepatocarcinoma cells by TUNEL assay. Telomerase activity, hTERT transcription level and p- p70 S6k was demonstrated by the telomeric repeat amplification protocol and silver staining assay, Dual-Luciferase Reporter Assay and Western blot analysis respectively. Results Treating SMMC-7721 cells with 5-Fu leads to apoptosis of the cells, and reduction in telomerase activity, as well as a dramatic reduction in the activated form of p70 S6 kinase, a mTOR substrate. The 5-Fu treatment nearly abolishes transcription of hTERT (the major component of telomerase mRNA. Treating SMMC-7721 cells with Rapamycin, a specific mTOR inhibitor, significantly reduce hTERT protein level but did not affect hTERT transcription. 5-Fu and rapamycin were synergistic in regards to down-regulation of telomerase activity in hepatocarcinoma cells. Conclusion These results suggest that chemotherapeutic agent 5-Fu may down-regulate telomerase activity at both transcriptional level and PI3K/Akt/mTOR pathway-dependent post-transcriptional level to facilitate hepatocellular carcinoma cell apoptosis.

  13. Inferring the functional effect of gene expression changes in signaling pathways

    Science.gov (United States)

    Sebastián-León, Patricia; Carbonell, José; Salavert, Francisco; Sanchez, Rubén; Medina, Ignacio; Dopazo, Joaquín

    2013-01-01

    Signaling pathways constitute a valuable source of information that allows interpreting the way in which alterations in gene activities affect to particular cell functionalities. There are web tools available that allow viewing and editing pathways, as well as representing experimental data on them. However, few methods aimed to identify the signaling circuits, within a pathway, associated to the biological problem studied exist and none of them provide a convenient graphical web interface. We present PATHiWAYS, a web-based signaling pathway visualization system that infers changes in signaling that affect cell functionality from the measurements of gene expression values in typical expression microarray case–control experiments. A simple probabilistic model of the pathway is used to estimate the probabilities for signal transmission from any receptor to any final effector molecule (taking into account the pathway topology) using for this the individual probabilities of gene product presence/absence inferred from gene expression values. Significant changes in these probabilities allow linking different cell functionalities triggered by the pathway to the biological problem studied. PATHiWAYS is available at: http://pathiways.babelomics.org/. PMID:23748960

  14. A SNARE-protein has opposing functions in penetration resistance and defence signalling pathways

    DEFF Research Database (Denmark)

    Zhang, Ziguo; Feechan, Angela; Pedersen, Carsten

    2007-01-01

    Penetration resistance is often the first line of defence against fungal pathogens. Subsequently induced defences are mediated by the programmed cell death (PCD) reaction pathway and the salicylic acid (SA), jasmonic acid (JA) and ethylene (ET) signalling pathways. We previously demonstrated...

  15. mTOR inhibition elicits a dramatic response in PI3K-dependent colon cancers.

    Directory of Open Access Journals (Sweden)

    Dustin A Deming

    Full Text Available The phosphatidylinositide-3-kinase (PI3K signaling pathway is critical for multiple cellular functions including metabolism, proliferation, angiogenesis, and apoptosis, and is the most commonly altered pathway in human cancers. Recently, we developed a novel mouse model of colon cancer in which tumors are initiated by a dominant active PI3K (FC PIK3ca. The cancers in these mice are moderately differentiated invasive mucinous adenocarcinomas of the proximal colon that develop by 50 days of age. Interestingly, these cancers form without a benign intermediary or aberrant WNT signaling, indicating a non-canonical mechanism of tumorigenesis. Since these tumors are dependent upon the PI3K pathway, we investigated the potential for tumor response by the targeting of this pathway with rapamycin, an mTOR inhibitor. A cohort of FC PIK3ca mice were treated with rapamycin at a dose of 6 mg/kg/day or placebo for 14 days. FDG dual hybrid PET/CT imaging demonstrated a dramatic tumor response in the rapamycin arm and this was confirmed on necropsy. The tumor tissue remaining after treatment with rapamycin demonstrated increased pERK1/2 or persistent phosphorylated ribosomal protein S6 (pS6, indicating potential resistance mechanisms. This unique model will further our understanding of human disease and facilitate the development of therapeutics through pharmacologic screening and biomarker identification.

  16. Intercellular signaling pathways active during and after growth and differentiation of the lumbar vertebral growth plate.

    Science.gov (United States)

    Dahia, Chitra Lekha; Mahoney, Eric J; Durrani, Atiq A; Wylie, Christopher

    2011-06-15

    Vertebral growth plates at different postnatal ages were assessed for active intercellular signaling pathways. To generate a spatial and temporal map of the major signaling pathways active in the postnatal mouse lumbar vertebral growth plate. The growth of all long bones is known to occur by cartilaginous growth plates. The growth plate is composed of layers of chondrocyets that actively proliferate, differentiate, die and, are replaced by bone. The role of major cell signaling pathways has been suggested for regulation of the fetal long bones. But not much is known about the molecular or cellular signals that control the postnatal vertebral growth plate and hence postnatal vertebral bone growth. Understanding such molecular mechanisms will help design therapeutic treatments for vertebral growth disorders such as scoliosis. Antibodies against activated downstream intermediates were used to identify cells in the growth plate responding to BMP, TGFβ, and FGF in cryosections of lumbar vertebrae from different postnatal age mice to identify the zones that were responding to these signals. Reporter mice were used to identify the chondrocytes responding to hedgehog (Ihh), and Wnt signaling. We present a spatial/temporal map of these signaling pathways during growth, and differentiation of the mouse lumbar vertebral growth plate. During growth and differentiation of the vertebral growth plate, its different components respond at different times to different intercellular signaling ligands. Response to most of these signals is dramatically downregulated at the end of vertebral growth.

  17. Evolution and Design Governing Signal Precision and Amplification in a Bacterial Chemosensory Pathway.

    Directory of Open Access Journals (Sweden)

    Mathilde Guzzo

    2015-08-01

    Full Text Available Understanding the principles underlying the plasticity of signal transduction networks is fundamental to decipher the functioning of living cells. In Myxococcus xanthus, a particular chemosensory system (Frz coordinates the activity of two separate motility systems (the A- and S-motility systems, promoting multicellular development. This unusual structure asks how signal is transduced in a branched signal transduction pathway. Using combined evolution-guided and single cell approaches, we successfully uncoupled the regulations and showed that the A-motility regulation system branched-off an existing signaling system that initially only controlled S-motility. Pathway branching emerged in part following a gene duplication event and changes in the circuit structure increasing the signaling efficiency. In the evolved pathway, the Frz histidine kinase generates a steep biphasic response to increasing external stimulations, which is essential for signal partitioning to the motility systems. We further show that this behavior results from the action of two accessory response regulator proteins that act independently to filter and amplify signals from the upstream kinase. Thus, signal amplification loops may underlie the emergence of new connectivity in signal transduction pathways.

  18. Dietary influence on MAPK-signaling pathways and risk of colon and rectal cancer.

    Science.gov (United States)

    Slattery, Martha L; Lundgreen, Abbie; Wolff, Roger K

    2013-01-01

    Mitogen-activated protein kinase (MAPK) pathways regulate cellular functions including cell proliferation, differentiation, migration, and apoptosis. Associations between genes in the DUSP, ERK1/2, JNK, and p38 MAPK-signaling pathways and dietary factors associated with growth factors, inflammation, and oxidative stress and risk of colon and rectal cancer were evaluated. Data include colon cases (n = 1555) and controls (n = 1956) and rectal cases (n = 754) and controls (n = 959). Statistically significant interactions were observed for the MAPK-signaling pathways after adjustment for multiple comparisons. DUSP genes interacted with carbohydrates, mutagen index, calories, calcium, vitamin D, lycopene, dietary fats, folic acid, and selenium. MAPK1, MAPK3, MAPK1, and RAF1 within the ERK1/2 MAPK-signaling pathway interacted with dietary fats and cruciferous vegetables. Within the JNK MAPK-signaling pathway, interactions between MAP3K7 and protein, vitamin C, iron, folic acid, carbohydrates, and cruciferous vegetables; MAP3K10 and folic acid; MAP3K9 and lutein/zeaxanthin; MAPK8 and calcium; MAP3K3 and calcium and lutein; MAP3K1 and cruciferous vegetables. Interaction within the p38-signaling pathway included MAPK14 with calories, carbohydrates saturated fat, selenium, vitamin C; MAP3K2 and carbohydrates, and folic acid. These data suggest that dietary factors involved in inflammation and oxidative stress interact with MAPK-signaling genes to alter risk of colorectal cancer.

  19. Regulation of PCP by the Fat signaling pathway

    Science.gov (United States)

    Matis, Maja; Axelrod, Jeffrey D.

    2013-01-01

    Planar cell polarity (PCP) in epithelia, orthogonal to the apical–basal axis, is essential for numerous developmental events and physiological functions. Drosophila model systems have been at the forefront of studies revealing insights into mechanisms regulating PCP and have revealed distinct signaling modules. One of these, involving the atypical cadherins Fat and Dachsous and the ectokinase Four-jointed, appears to link the direction of cell polarization to the tissue axes. We discuss models for the function of this signaling module as well as several unanswered questions that may guide future investigations. PMID:24142873

  20. [The function of transcription factor P63 and its signaling pathway during limb development].

    Science.gov (United States)

    Ma, Wei; Tian, Wen

    2014-08-01

    The development of human limb is controlled by several transcription factors and signaling pathways, which are organized in precise time- and space-restricted manners. Recent studies showed that P63 and its signaling pathway play important roles in this process. Transcription factor P63, one member of the P53 family, is characterized by a similar amino acid domain, plays a crucial role in the development of limb and ectoderm differentiation, especially with its DNA binding domain, and sterile alpha motif domains. Mutated P63 gene may produce abnormal transcription factor P63 which can affect the signaling pathway. Furthermore, defective signaling protein in structure and/or quantity is synthesized though the pathway. Eventually, members of the signaling protein family are involved in the regulation of differentiation and development of stem cell, which causes deformity of limbs. In brief, three signaling pathways are related to the digit formation along three axes, including SHH-ZPA, FGFs-AER and Lmx1B-Wnt7a-En1. Each contains numerous signaling molecules which are integrated in self-regulatory modules that assure the acquisition or the correct digit complements. These finding has brought new clues for deciphering the etiology of congenital limb malformation and may provide alternatives for both prevention and treatment.