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Paradoxical effect of rapamycin on inflammatory stress-induced insulin resistance in vitro and in vivo

Yang, P; Zhao, Y; Zhao, L; Yuan, J; Chen, Y; Varghese, Z; Moorhead, JF; ... Ruan, XZ; + view all (2015) Paradoxical effect of rapamycin on inflammatory stress-induced insulin resistance in vitro and in vivo. Scientific Reports , 5 , Article 14959. 10.1038/srep14959. Green open access

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Abstract

Insulin resistance is closely related to inflammatory stress and the mammalian target of rapamycin/S6 kinase (mTOR/S6K) pathway. The present study investigated whether rapamycin, a specific inhibitor of mTOR, ameliorates inflammatory stress-induced insulin resistance in vitro and in vivo. We used tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) stimulation in HepG2 hepatocytes, C2C12 myoblasts and 3T3-L1 adipocytes and casein injection in C57BL/6J mice to induce inflammatory stress. Our results showed that inflammatory stress impairs insulin signaling by reducing the expression of total IRS-1, p-IRS-1 (tyr632), and p-AKT (ser473); it also activates the mTOR/S6K signaling pathway both in vitro and in vivo. In vitro, rapamycin treatment reversed inflammatory cytokine-stimulated IRS-1 serine phosphorylation, increased insulin signaling to AKT and enhanced glucose utilization. In vivo, rapamycin treatment also ameliorated the impaired insulin signaling induced by inflammatory stress, but it induced pancreatic β-cell apoptosis, reduced pancreatic β-cell function and enhanced hepatic gluconeogenesis, thereby resulting in hyperglycemia and glucose intolerance in casein-injected mice. Our results indicate a paradoxical effect of rapamycin on insulin resistance between the in vitro and in vivo environments under inflammatory stress and provide additional insight into the clinical application of rapamycin.

Type: Article
Title: Paradoxical effect of rapamycin on inflammatory stress-induced insulin resistance in vitro and in vivo
Open access status: An open access version is available from UCL Discovery
DOI: 10.1038/srep14959
Publisher version: http://doi.org/10.1038/srep14959
Language: English
Additional information: This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/
Keywords: Science & Technology, Multidisciplinary Sciences, Science & Technology - Other Topics, NECROSIS-FACTOR-ALPHA, C-REACTIVE PROTEIN, BETA-CELL FUNCTION, GLUCOSE-UPTAKE, ADIPOSE-TISSUE, AMINO-ACID, HEPATIC GLUCONEOGENESIS, RECEPTOR SUBSTRATE-1, DIABETES-MELLITUS, MAMMALIAN TARGET
UCL classification: UCL
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Medical Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Medical Sciences > Div of Medicine
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Medical Sciences > Div of Medicine > Inst for Liver and Digestive Hlth
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Medical Sciences > Div of Medicine > Renal Medicine
URI: https://discovery.ucl.ac.uk/id/eprint/1508257
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