Document Detail


Increased mitochondrial fatty acid oxidation is sufficient to protect skeletal muscle cells from palmitate-induced apoptosis.
MedLine Citation:
PMID:  20837491     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The mechanisms underlying the protective effect of monounsaturated fatty acids (e.g. oleate) against the lipotoxic action of saturated fatty acids (e.g. palmitate) in skeletal muscle cells remain poorly understood. This study aimed to examine the role of mitochondrial long-chain fatty acid (LCFA) oxidation in mediating oleate's protective effect against palmitate-induced lipotoxicity. CPT1 (carnitine palmitoyltransferase 1), which is the key regulatory enzyme of mitochondrial LCFA oxidation, is inhibited by malonyl-CoA, an intermediate of lipogenesis. We showed that expression of a mutant form of CPT1 (CPT1mt), which is active but insensitive to malonyl-CoA inhibition, in C2C12 myotubes led to increased LCFA oxidation flux even in the presence of high concentrations of glucose and insulin. Furthermore, similar to preincubation with oleate, CPT1mt expression protected muscle cells from palmitate-induced apoptosis and insulin resistance by decreasing the content of deleterious palmitate derivates (i.e. diacylglycerols and ceramides). Oleate preincubation exerted its protective effect by two mechanisms: (i) in contrast to CPT1mt expression, oleate preincubation increased the channeling of palmitate toward triglycerides, as a result of enhanced diacylglycerol acyltransferase 2 expression, and (ii) oleate preincubation promoted palmitate oxidation through increasing CPT1 expression and modulating the activities of acetyl-CoA carboxylase and AMP-activated protein kinase. In conclusion, we demonstrated that targeting mitochondrial LCFA oxidation via CPT1mt expression leads to the same protective effect as oleate preincubation, providing strong evidence that redirecting palmitate metabolism toward oxidation is sufficient to protect against palmitate-induced lipotoxicity.
Authors:
Carole Henique; Abdelhak Mansouri; Gwladys Fumey; Veronique Lenoir; Jean Girard; Frederic Bouillaud; Carina Prip-Buus; Isabelle Cohen
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2010-09-12
Journal Detail:
Title:  The Journal of biological chemistry     Volume:  285     ISSN:  1083-351X     ISO Abbreviation:  J. Biol. Chem.     Publication Date:  2010 Nov 
Date Detail:
Created Date:  2010-11-15     Completed Date:  2011-02-28     Revised Date:  2011-12-21    
Medline Journal Info:
Nlm Unique ID:  2985121R     Medline TA:  J Biol Chem     Country:  United States    
Other Details:
Languages:  eng     Pagination:  36818-27     Citation Subset:  IM    
Affiliation:
Institut Cochin, Université Paris Descartes UMRS1016, CNRS (UMR 8104), 75014 Paris, France.
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MeSH Terms
Descriptor/Qualifier:
Animals
Apoptosis*
Blotting, Western
Carnitine O-Palmitoyltransferase / metabolism
Cells, Cultured
Fluorescent Antibody Technique
Mice
Mitochondria / metabolism*
Muscle Fibers, Skeletal / cytology,  drug effects*,  metabolism
Muscle, Skeletal / drug effects*,  pathology*
Oleic Acid / chemistry*,  metabolism
Oxidation-Reduction
Oxygen Consumption
Palmitates / pharmacology*
RNA, Messenger / genetics
Reverse Transcriptase Polymerase Chain Reaction
Chemical
Reg. No./Substance:
0/Palmitates; 0/RNA, Messenger; 112-80-1/Oleic Acid; EC 2.3.1.21/Carnitine O-Palmitoyltransferase

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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