title: Phosphorylation inactivation of endothelial nitric oxide synthesis in pulmonary arterial hypertension.
abstract: The impairment of vasodilator nitric oxide (NO) production is well accepted as a typical marker of endothelial dysfunction in vascular diseases, including in the pathophysiology of pulmonary arterial hypertension (PAH), but the molecular mechanisms accounting for loss of NO production are unknown. We hypothesized that low NO production by pulmonary arterial endothelial cells in PAH is due to inactivation of NO synthase (eNOS) by aberrant phosphorylation of the protein. To test the hypothesis, we evaluated eNOS levels, dimerization, and phosphorylation in the vascular endothelial cells and lungs of patients with PAH compared with controls. In mechanistic studies, eNOS activity in endothelial cells in PAH lungs was found to be inhibited due to phosphorylation at T495. Evidence pointed to greater phosphorylation/activation of protein kinase C (PKC) α and its greater association with eNOS as the source of greater phosphorylation at T495. The presence of greater amounts of pT495-eNOS in plexiform lesions in lungs of patients with PAH confirmed the pathobiological mechanism in vivo. Transfection of the activating mutation of eNOS (T495A/S1177D) restored NO production in PAH cells. Pharmacological blockade of PKC activity by β-blocker also restored NO formation by PAH cells, identifying one mechanism by which β-blockers may benefit PAH and cardiovascular diseases through recovery of endothelial functions.
authors.affiliation: Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio;
authors.forename: Sudakshina
authors.initials: S
authors.lastname: Ghosh
authors.affiliation: Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio;
authors.forename: Manveen
authors.initials: M
authors.lastname: Gupta
authors.affiliation: Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio;
authors.forename: Weiling
authors.initials: W
authors.lastname: Xu
authors.affiliation: Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio;
authors.forename: Deloris A
authors.initials: DA
authors.lastname: Mavrakis
authors.affiliation: Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio;
authors.forename: Allison J
authors.initials: AJ
authors.lastname: Janocha
authors.affiliation: Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio;
authors.forename: Suzy A A
authors.initials: SA
authors.lastname: Comhair
authors.affiliation: Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio;
authors.forename: Mohammad Mahfuzul
authors.initials: MM
authors.lastname: Haque
authors.affiliation: Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio;
authors.forename: Dennis J
authors.initials: DJ
authors.lastname: Stuehr
authors.affiliation: Boston University School of Medicine, Boston, Massachusetts;
authors.forename: Jun
authors.initials: J
authors.lastname: Yu
authors.affiliation: Tupper Research Institute and Pulmonary, Critical Care, and Sleep Division, Tufts Medical Center, Boston, Massachusetts; and.
authors.forename: Peter
authors.initials: P
authors.lastname: Polgar
authors.affiliation: Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio;
authors.forename: Sathyamangla V
authors.initials: SV
authors.lastname: Naga Prasad
authors.affiliation: Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio; Respiratory Institute, Cleveland Clinic, Cleveland, Ohio erzurus@ccf.org.
authors.forename: Serpil C
authors.initials: SC
authors.lastname: Erzurum
mesh_terms: D000328:Adult; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000201:enzymology*; D005260:Female; D006801:Humans; D006976:Hypertension, Pulmonary / Q000201:enzymology* / Q000473:pathology; D008168:Lung / Q000201:enzymology / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000096:biosynthesis; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism*; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism; D011499:Protein Processing, Post-Translational
chemical_list: D009569:Nitric Oxide; C496314:NOS3 protein, human; D052250:Nitric Oxide Synthase Type III; D011493:Protein Kinase C
keywords: endothelial cells; nitric oxide; protein kinases