Human Pulmonary Artery Endothelial Cells Increased Glycolysis and Decreased Nitric Oxide Synthase O-GlcNAcylation in Pulmonary Arterial Hypertension

Abstract

Pulmonary arterial hypertension (PAH) is a fatal disease that primarily affects women. In PAH, endothelial cells become dysfunctional, reducing production of the vasodilator nitric oxide while increasing proliferation. Other studies suggest altered glucose metabolism in PAH. Our recent study showed that increased endothelial glucose metabolism in disturbed flow increased O-GlcNAcylation of endothelial nitric oxide synthase (eNOS), the enzyme that makes nitric oxide, which then reduced nitric oxide production. We therefore hypothesized that elevated endothelial glycolytic activity in PAH endothelial cells would reduce nitric oxide production by increasing eNOS O-GlcNAcylation. We cultured human pulmonary artery endothelial cells (HPAECs) from failed lung transplant (“non-PAH”) and idiopathic PAH patients (“PAH”) and quantified glycolytic activity, nitric oxide production, and eNOS O-GlcNAcylation in each cell type. Our data show that PAH HPAECs had higher glucose uptake and glycolytic metabolites, as well as decreased nitric oxide production, compared to non-PAH HPAECs. However, PAH HPAECs had lower eNOS O-GlcNAcylation and UDP-GlcNAc, the substrate for O-GlcNAcylation. Interestingly, both glucose uptake and eNOS O-GlcNAcylation were higher in female as compared to male HPAECs. These data suggest that although endothelial glycolytic metabolism is altered in PAH, eNOS O-GlcNAcylation is not connected to decreased nitric oxide. In addition, differences in glucose metabolism and protein O-GlcNAcylation in HPAECs from male and female donors could relate to PAH sexual dimorphism.