Peroxisomal biogenesis occurs in response to obesity and to a high lipid environment in human skeletal muscle (1159.5)

Obesity is associated with elevated levels of lipids and reductions in mitochondrial fatty acid oxidation in skeletal muscle, both of which are associated with insulin resistance. Known almost exclusively for their actions in liver, peroxisomes are critical subcellular compartments essential for chain-shortening very long- and long-chain fatty acids to acyl-carnitines which are hypothesized to permit CPT-1 independent entry into the mitochondria for subsequent oxidation. We hypothesize that peroxisomes proliferate in human skeletal muscle as an adaptive response to a high lipid environment to facilitate mitochondrial fatty acid oxidation. Assays for peroxisomal membrane protein 70 (PMP70) and peroxisomal biogenesis factor PEX 19 protein content, and peroxisomal-mitochondrial co-localization were assessed in vastus lateralis from obese and lean humans and after lipid incubation in human skeletal muscle primary myotubes. Results: 1) A peroxisomal-mitochondrial co-localization was identified in human skeleta...