文章基本信息

标题：PPARγ coactivator-1α contributes to exercise-induced regulation of intramuscular lipid droplet programming in mice and humans
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作者：Timothy R. Koves ; Lauren M. Sparks ; J. P. Kovalik 等
期刊名称：JLR Papers In Press
印刷版ISSN：0022-2275
电子版ISSN：1539-7262
出版年度：2013
卷号：54
期号：2
页码：522-534
DOI：10.1194/jlr.P028910
语种：English
出版社：American Society for Biochemistry and Molecular Biology
摘要：Intramuscular accumulation of triacylglycerol, in the form of lipid droplets (LD), has gained widespread attention as a hallmark of metabolic disease and insulin resistance. Paradoxically, LDs also amass in muscles of highly trained endurance athletes who are exquisitely insulin sensitive. Understanding the molecular mechanisms that mediate the expansion and appropriate metabolic control of LDs in the context of habitual physical activity could lead to new therapeutic opportunities. Herein, we show that acute exercise elicits robust upregulation of a broad program of genes involved in regulating LD assembly, morphology, localization, and mobilization. Prominent among these was perilipin-5, a scaffolding protein that affects the spatial and metabolic interactions between LD and their surrounding mitochondrial reticulum. Studies in transgenic mice and primary human skeletal myocytes established a key role for the exercise-responsive transcriptional coactivator PGC-1α in coordinating intramuscular LD programming with mitochondrial remodeling. Moreover, translational studies comparing physically active versus inactive humans identified a remarkably strong association between expression of intramuscular LD genes and enhanced insulin action in exercise-trained subjects. These results reveal an intimate molecular connection between intramuscular LD biology and mitochondrial metabolism that could prove relevant to the etiology and treatment of insulin resistance and other disorders of lipid imbalance.
关键词：skeletal muscle ; athlete's paradox ; mitochondria ; fatty acid metabolism ; insulin sensitivity ; gene regulation