Nitrotyrosine impairs mitochondrial function in fetal lamb pulmonary artery endothelial cells.
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.
Department of Pediatrics, Medical College of Wisconsin, Wauwatosa, Wisconsin rteng@mcw.edu.
Ru-Jeng
RJ
Teng
Department of Pediatrics, Medical College of Wisconsin, Wauwatosa, Wisconsin.
Tzong-Jin
TJ
Wu
Department of Pediatrics, Medical College of Wisconsin, Wauwatosa, Wisconsin.
Adeleye J
AJ
Afolayan
Department of Pediatrics, Medical College of Wisconsin, Wauwatosa, Wisconsin.
Girija G
GG
Konduri
D000107:Acetylation; D000818:Animals; D002478:Cells, Cultured; D004272:DNA, Mitochondrial / Q000096:biosynthesis; D004305:Dose-Response Relationship, Drug; D045222:Electron Transport Chain Complex Proteins / Q000378:metabolism; D042783:Endothelial Cells / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D005865:Gestational Age; D018841:HSP90 Heat-Shock Proteins / Q000378:metabolism; D008870:Microtubules / Q000187:drug effects / Q000378:metabolism; D008928:Mitochondria / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism; D010101:Oxygen Consumption / Q000187:drug effects; D011485:Protein Binding; D011651:Pulmonary Artery / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D012756:Sheep; D013481:Superoxides / Q000378:metabolism; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000633:toxicity
D004272:DNA, Mitochondrial; D045222:Electron Transport Chain Complex Proteins; D018841:HSP90 Heat-Shock Proteins; D013481:Superoxides; C002744:3-nitrotyrosine; D014443:Tyrosine; D052250:Nitric Oxide Synthase Type III
bioenergetics; microtubules; mitochondria; nitric oxide