Insulin resistance in skeletal muscle plays a major role in the development of type 2 diabetes and may be causally associated with increases in intramuscular fatty acid metabolites. Fatty acid transport protein 1 (FATP1) is an acyl-CoA synthetase highly expressed in skeletal muscle and modulates fatty acid uptake and metabolism by converting fatty acids into fatty acyl-CoA. To investigate the role of FATP1 in glucose homeostasis and in the pathogenesis of insulin resistance, we examined the effect of acute lipid infusion or chronic high-fat feeding on insulin action in FATP1 KO mice. Whole-body adiposity, adipose tissue expression of adiponectin, intramuscular fatty acid metabolites, and insulin sensitivity were not altered in FATP1 KO mice fed a regular chow diet. In contrast, FATP1 deletion protected the KO mice from fat-induced insulin resistance and intramuscular accumulation of fatty acyl-CoA without alteration in whole-body adiposity. These findings demonstrate an important role of intramuscular fatty acid metabolites in causing insulin resistance and suggest that FATP1 may be a novel therapeutic target for the treatment of insulin resistance and type 2 diabetes.
Jason K. Kim, Ruth E. Gimeno, Takamasa Higashimori, Hyo-Jeong Kim, Hyejeong Choi, Sandhya Punreddy, Robin L. Mozell, Guo Tan, Alain Stricker-Krongrad, David J. Hirsch, Jonathan J. Fillmore, Zhen-Xiang Liu, Jianying Dong, Gary Cline, Andreas Stahl, Harvey F. Lodish, Gerald I. Shulman
Metabolic parameters during basal (overnight-fasted) and hyperinsulinemic-euglycemic clamp periods in the WT and FATP1 KO mice with or without lipid infusion or high-fat feeding