Dynamic nitrosation - palmitoylation of CD36 regulates serum lipids

Regulation of endothelial cell (EC) lipid content is crucial for cell and organ function. During obesity, ECs become lipid laden leading to lipotoxicity and endothelial dysfunction which further contribute to metabolic syndrome progression. Here, we demonstrate a novel pathway by which the endothelium, via eNOS-dependent nitrosation, inhibits excess lipid accumulation during hyperlipidemic conditions in obesity. In the vasculature, nitric oxide has been reported as a potent vasodilator. However, we highlight a new role for nitric oxide as a modulator of serum lipids. We show this occurs as a result of the downregulation of Cav1, a potent negative regulator of endothelial nitric oxide synthase, increasing EC endogenous nitric oxide synthesis. Using EC-specific Cav1 knockout mice, we are able to increase nitric oxide in vivo. This increased nitric oxide leads to nitrosation of cysteines 3 and 466 on the cytoplasmic tails of CD36, a fatty acid translocase, disrupting palmitoylation of these residues and subsequently inhibiting trafficking of CD36 to the plasma membrane. Together, this work suggests that CD36 nitrosation occurs as a protective mechanism to prevent lipotoxicity and EC dysfunction during the progression of metabolic syndrome.