Protective Effect of PGC-1 on Lipid Overload-induced Apoptosis in Vascular Endothelial Cell

Background: Fatty acids contribute to endothelial cell dysfunction and apoptosis by inducing accumulation of long chain fatty acyl CoA (LCAC), which increases oxidative stress in vascular endothelial cells. Forced expression of PGC-1 was shown to induce mitochondrial biogenesis and to control expression of mitochondrial enzymes involved in fatty acid oxidation. This study was undertaken to test the hypothesis that PGC-1 overexpression could prevent endothelial cell apoptosis by enhancing fatty acid oxidation and relieving oxidative stress in vascular endothelium. Methods: Adenoviruses containing human PGC-1 (Ad-PGC-1) and -galactosidase (Ad--gal) were transfected to confluent human aortic endothelial cells (HAECs). To investigate the effect of adenoviral PGC-1 gene transfer on apoptosis, combined treatment of linoleic acid (LA), an unsaturated fatty acid, was performed. Results: PGC-1 overexpression inhibited the increase in ROS production and apoptosis of HAECs induced by LA. Also, PGC-1 led to a significant increase in fatty acid oxidation and decrease in triglyceride content in HAECs. LA caused the decrease of adenine nucleotide translocase (ANT) activity and transient mitochondrial hyperpolarization, which was followed by depolarization. PGC-1 overexpression prevented these processes. Conclusion: In summary, PGC-1 overexpression inhibited mitochondrial dysfunction and apoptosis by facilitating fatty acid oxidation and protecting against the damage from oxidative stress in HAECs. The data collectively suggest that the regulation of intracellular PGC-1 expression might play a critical role in preventing atherosclerosis.