Background: During obesity, endothelial cells (ECs) become lipid laden, leading to endothelial dysfunction. We tested posttranslational modification on cluster of differentiation 36 (CD36) that may regulate EC lipid accumulation.
Methods: We used an EC-specific Cav1 (caveolin-1) knockout mouse, nitrosation and palmitoylation assays, and whole animal Nγ-nitro-l-arginine methyl ester administration to examine blood lipids.
Results: EC-specific Cav1 knockout male mice are hyperlipidemic regardless of diet but retain endothelial cell function. We found these mice have significantly increased NO in response to the lack of Cav1, and the presence or absence of NO toggled inversely EC lipid content and plasma lipid in mice. The NO nitrosated the fatty acid translocase CD36 at the same cysteines that are palmitoylated on CD36. The nitrosation of CD36 prevented its trafficking to the plasma membrane and decreased lipid accumulation. The physiological effect of this mechanism was a reliance on NO for endothelial function and not dilation.
Conclusions: This work suggests that CD36 nitrosation occurs as a protective mechanism to prevent EC lipotoxicity.
Keywords: cell membrane; fatty acids; hyperlipidemias; lipoylation; nitrosation.