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You-Yang Zhao, Yidan D. Zhao, Muhammad K. Mirza, Julia H. Huang, Hari-Hara S.K. Potula, Steven M. Vogel, Viktor Brovkovych, Jason X.-J. Yuan, John Wharton, Asrar B. Malik
Published in Volume 119, Issue 7
J Clin Invest. 2009; 119(7):2009–2018 doi:10.1172/JCI33338
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Jci33338
Figure 9
PKG tyrosine nitration in lung tissue from IPAH patients.

(A) Quantitative analysis of eNOS-derived NOx in human lung tissue. Following 20 minutes incubation with selective inhibitors, lung tissues were incubated with 1 mM l-arginine for 3 hours. eNOS-derived NOx was determined by measuring the concentration of nitrite and nitrate in the medium with the Griess reagent. Bars represent mean. *P < 0.01 versus normal. IPAH lungs produced 2-fold greater eNOS-derived NOx than normal lungs. (B) PKG tyrosine nitration in IPAH lungs. Each lysate (150 μg) was immunoprecipitated with anti–PKG-1 and immunoblotted with anti-nitrotyrosine for detection of PKG tyrosine nitration. IPAH lungs exhibited prominent PKG-1 tyrosine nitration compared with normal lungs. Protein levels of PKG-1, eNOS, and caveolin-1 were also determined by Western blotting with anti–PKG-1, -eNOS, or –caveolin-1 antibody, respectively. Immunoblot of GAPDH was used as loading control. (C) Densitometric analysis of PKG-1 tyrosine nitration. The intensity of each band of PKG-1 tyrosine nitration (PKG-1–NT) was normalized to the intensity of the respective PKG-1 band. PKG-1 tyrosine nitration increased 2-fold in IPAH lungs compared with normal lungs. Bars represent mean. *P < 0.05 (n = 3–4). (D) Proposed model of PKG nitration–mediated PH. Persistent eNOS activation secondary to caveolin-1 deficiency (Cav1–/– mice or IPAH patients) leads to formation of peroxynitrite in the pulmonary vasculature and impairment of PKG kinase activity through tyrosine nitration. Impaired PKG signaling induces pulmonary vascular remodeling and vasoconstriction, and thereby PH.