Increased lipid accumulation and insulin resistance in transgenic mice expressing DGAT2 in glycolytic (type II) muscle

MC Levin, M Monetti, MJ Watt… - American Journal …, 2007 - journals.physiology.org
MC Levin, M Monetti, MJ Watt, MP Sajan, RD Stevens, JR Bain, CB Newgard, RV Farese Sr
American Journal of Physiology-Endocrinology and Metabolism, 2007journals.physiology.org
Insulin resistance and type 2 diabetes are frequently accompanied by lipid accumulation in
skeletal muscle. However, it is unknown whether primary lipid deposition in skeletal muscle
is sufficient to cause insulin resistance or whether the type of muscle fiber, oxidative or
glycolytic fiber, is an important determinant of lipid-mediated insulin resistance. Here we
utilized transgenic mice to test the hypothesis that lipid accumulation specifically in glycolytic
muscle promotes insulin resistance. Overexpression of DGAT2, which encodes an acyl-CoA …
Insulin resistance and type 2 diabetes are frequently accompanied by lipid accumulation in skeletal muscle. However, it is unknown whether primary lipid deposition in skeletal muscle is sufficient to cause insulin resistance or whether the type of muscle fiber, oxidative or glycolytic fiber, is an important determinant of lipid-mediated insulin resistance. Here we utilized transgenic mice to test the hypothesis that lipid accumulation specifically in glycolytic muscle promotes insulin resistance. Overexpression of DGAT2, which encodes an acyl-CoA:diacylglycerol acyltransferase that catalyzes triacylglycerol (TG) synthesis, in glycolytic muscle of mice increased the content of TG, ceramides, and unsaturated long-chain fatty acyl-CoAs in young adult mice. This lipid accumulation was accompanied by impaired insulin signaling and insulin-mediated glucose uptake in glycolytic muscle and impaired whole body glucose and insulin tolerance. We conclude that DGAT2-mediated lipid deposition specifically in glycolytic muscle promotes insulin resistance in this tissue and may contribute to the development of diabetes.
American Physiological Society