| mTOR partly mediates insulin resistance by phosphorylation of insulin receptor substrate-1 on serine³⁰⁷ residues after burn. | |
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MedLine Citation:
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PMID: 20594757 Owner: NLM Status: In-Process |
Abstract/OtherAbstract:
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Mammalian target of rapamycin (mTOR) is an important mediator for cross talk between nutritional signals and metabolic signals of insulin by downregulating insulin receptor substrate proteins. Therefore, mTOR inhibition could become a therapeutic strategy in insulin-resistant states, including insulin resistance induced by burn. We tested this hypothesis in the rat model of 30% TBSA full thickness burn, using the mTOR inhibitor rapamycin. Rapamycin (0.4 mg/kg, i.p.) was injected 2 h before euglycemic-hyperinsulinemic glucose clamps at 4 days after burn. IRS-1, phospho-serine³⁰⁷, phospho-tyrosine of IRS-1 and phospho-mTOR in muscle tissue were determined by immunoprecipitation and Western blot analysis or immunohistochemistry. Plasma TNF-α, insulin and C-peptide were determined before and after euglycemic-hyperinsulinemic glucose clamps. Our data showed that TNF-α, insulin and C-peptide significantly increased in the early stage after burn (P < 0.01). The infused rates of total 10% glucose (GIR, mg/kg min) significantly decreased at 4 days after burn. The level of IRS-1 serine³⁰⁷ phosphorylation in muscle in vivo significantly increased after burn (P < 0.01), while insulin-induced tyrosine phosphorylation of IRS-1 significantly decreased (P < 0.01). Inhibition of mTOR by rapamycin inhibited the phosphorylation of mTOR, reduced serine³⁰⁷ phosphorylation, elevated tyrosine phosphorylation and partly prevented the decrease of GIR after burn. However, TNF-α, insulin and C-peptide were not decreased by rapamycin treatment postburn. Taken together, these results indicate that the mTOR pathway is an important modulator of the signals involved in the acute regulation of insulin-stimulated glucose metabolism, and at least, partly contributes to burn-induced insulin resistance. mTOR inhibition may become a therapeutic strategy in insulin-resistant states after burn. |
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Authors:
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Chen Xin-Long; Xia Zhao-Fan; Ben Dao-Feng; Duo Wei |
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Publication Detail:
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Type: Journal Article Date: 2010-07-01 |
Journal Detail:
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Title: Burns : journal of the International Society for Burn Injuries Volume: 37 ISSN: 1879-1409 ISO Abbreviation: Burns Publication Date: 2011 Feb |
Date Detail:
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Created Date: 2010-12-27 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 8913178 Medline TA: Burns Country: Netherlands |
Other Details:
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Languages: eng Pagination: 86-93 Citation Subset: IM |
Copyright Information:
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Copyright © 2010 Elsevier Ltd and ISBI. All rights reserved. |
Affiliation:
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Department of Burn, Taizhou People's Hospital, Medical College of Yangzhou University, Jiangsu Province, Taizhou 225300, People's Republic of China. cxlcxlzxy@hotmail.com |
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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