Elevating Cytosolic NADPH Metabolism in Endothelial Cells Ameliorates Vascular Aging

NADPH metabolism is independently regulated in different compartments in endothelial cells (EC). The metabolic profile and functional impact of NADPH during EC senescence remain largely unknown. Using a genetically encoded fluorescent indicator (iNap), we found that cytosolic, but not mitochondrial, NADPH level increased during EC senescence. Upregulation of glucose-6-phosphate dehydrogenase (G6PD) further elevated cytosolic NADPH level during EC senescence. Suppression of nitric oxide-induced G6PD S-nitrosylation at C385 potentiated G6PD activity. G6PD overexpression alleviated, while its knockdown aggravated, vascular aging. NADPH is indispensable for G6PD to protect against vascular aging through increasing reduced glutathione and inhibiting HDAC3 activity. Among 1419 FDA-approved drugs, folic acid, catalyzed by methylenetetrahydrofolate dehydrogenase to generate NADPH, effectively alleviated vascular aging in angiotensin II-infused mice and naturally aged mice. The novel connection between NADPH metabolism and EC senescence provides a unique angle for understanding vascular aging and a new target for therapy.