Objective: Fatty acids increase reactive oxygen species generation and cell apoptosis in endothelial cells. The peroxisome proliferator-activated receptor-gamma coactivator 1-alpha (PGC-1alpha) is a transcriptional coactivator that increases mitochondrial biogenesis and fatty acid oxidation in various cells. This study was undertaken to investigate the possible preventive effect of PGC-1alpha on endothelial apoptosis and its molecular mechanism.
Methods and results: Treatment with linoleic acid in cultured human aortic endothelial cells increased reactive oxygen species generation and cell apoptosis. These effects appeared to be mediated by increases in cytosolic fat metabolites, ie, fatty acyl CoA, diacylglycerol, and ceramide, and consequent decreases in ATP/ADP translocase activity of adenine nucleotide translocator. Adenoviral overexpression of PGC-1alpha prevented linoleic acid-induced increases in reactive oxygen species generation and cell apoptosis in human aortic endothelial cells by increasing fatty acid oxidation, decreasing diacylglycerol and ceramide, and increasing ATP/ADP translocase activity. In isolated aorta, PGC-1alpha overexpression prevented linoleic acid-induced decrease in endothelium-dependent vasorelaxation, and this effect was abolished by adenine nucleotide translocator1 shRNA.
Conclusions: PGC-1alpha regulates reactive oxygen species generation and apoptosis in endothelial cells by increasing fatty acid oxidation and enhancing ATP/ADP translocase activity. Measures to increase PGC-1alpha expression or ATP/ADP translocase activity in vascular cells may aid in the prevention or treatment of atherosclerosis.