Nitrotyrosine impairs mitochondrial function in fetal lamb pulmonary artery endothelial cells

• Published in: American Journal of Physiology: Cell Physiology 2016-01, Vol.310 (1), p.C80-C88
• Main Authors: Teng, Ru-Jeng, Wu, Tzong-Jin, Afolayan, Adeleye J, Konduri, Girija G
• Format: Article
• Language: English
• Subjects: Acetylation; Amino acids; Animals; Cells; Cells, Cultured; DNA, Mitochondrial - biosynthesis; Dose-Response Relationship, Drug; Electron Transport Chain Complex Proteins - metabolism; Endothelial Cells - drug effects; Endothelial Cells - metabolism; Endothelial Cells - pathology; Endothelium; Gestational Age; HSP90 Heat-Shock Proteins - metabolism; Microtubules - drug effects; Microtubules - metabolism; Mitochondria; Mitochondria - drug effects; Mitochondria - metabolism; Mitochondria - pathology; Nitric Oxide Synthase Type III - metabolism; Nitrogen; Oxygen Consumption - drug effects; Polymerization; Protein Binding; Pulmonary Artery - drug effects; Pulmonary Artery - metabolism; Pulmonary Artery - pathology; Sheep; Superoxides - metabolism; Tyrosine - analogs & derivatives; Tyrosine - toxicity
• ISSN: 0363-6143; 1522-1563
• DOI: 10.1152/ajpcell.00073.2015

Nitration of both protein-bound and free tyrosine by reactive nitrogen species results in the formation of nitrotyrosine (NT). We previously reported that free NT impairs microtubule polymerization and uncouples endothelial nitric oxide synthase (eNOS) function in pulmonary artery endothelial cells (PAEC). Because microtubules modulate mitochondrial function, we hypothesized that increased NT levels during inflammation and oxidative stress will lead to mitochondrial dysfunction in PAEC. PAEC isolated from fetal lambs were exposed to varying concentrations of free NT. At low concentrations (1-10 μM), NT increased nitration of mitochondrial electron transport chain (ETC) protein subunit complexes I-V and state III oxygen consumption. Higher concentrations of NT (50 μM) caused decreased microtubule acetylation, impaired eNOS interactions with mitochondria, and decreased ETC protein levels. We also observed increases in heat shock protein-90 nitration, mitochondrial superoxide formation, and fragmentation of mitochondria in PAEC. Our data suggest that free NT accumulation may impair microtubule polymerization and exacerbate reactive oxygen species-induced cell damage by causing mitochondrial dysfunction.