The AGP-PPARγ axis promotes oxidative stress and diabetic endothelial cell dysfunction

Alkyl-glycerophosphate (AGP) accumulates in atherogenic oxidized-LDL and human atherosclerotic plaques and is a potent agonist of peroxisome-proliferator-activated receptor-gamma (PPARγ). Recent studies suggest a potential regulatory role for PPARγ in endothelial nitric oxide synthase (eNOS) expression/activation and nitrogen oxide (NO) generation in the vascular endothelium. Importantly, eNOS-induced NO and advanced glycation end-products (AGEs) are involved in blood-vessel damage, and diabetic patients exhibit high serum NO and AGE levels; however, the effect of AGP on NO- and AGE-mediated endothelium dysfunction remains unknown. Investigation of the AGP-specific effects on NO- and AGE-mediated dysfunction and the underlying molecular mechanisms revealed that AGP upregulated eNOS expression and NO production, and that eNOS silencing and PPARγ antagonism inhibited AGP-mediated eNOS upregulation and NO production. Moreover, AGP-PPARγ-axis-mediated NO production promoted the generation of reactive oxygen species and AGE formation. These results suggested that AGP plays a significant role in the initiation/progression of diabetes-related atherosclerosis through PPARγ activation.