Suppression of nuclear factor-kappa B activity by nitric oxide and hyperoxia in oxygen-resistant cells.
Inhaled nitric oxide (iNO) is used clinically to treat pulmonary hypertension in newborns, often in conjunction with hyperoxia (NO/O2). Prolonged exposure to NO/O2 causes synergistic lung injury and death of lung epithelial cells. To explore the mechanisms involved, oxygen-resistant HeLa-80 cells were exposed to NO +/- O2. Exposure to NO and O2 induced a synergistic cytotoxicity, accompanied with apoptotic characteristics, including elevated caspase-3-like activity, Annexin V incorporation, and nuclear condensation. This apoptosis was associated with a synergistic suppression of NF-kappaB activity. Cells lacking functional NF-kappaB p65 subunit were more sensitive to NO/O2 than their wild type counterparts. This injury was partially rescued by transfection with a p65 expression construct, suggesting an inverse relationship between NF-kappaB and susceptibility to the cytotoxicity of NO/O2. Despite the reduced NF-kappaB activity in cells exposed to NO +/- O2, IkappaBalpha was degraded, suggesting that pathways regulating the steady-state levels of IkappaB were not involved. However, exposure to NO/O2 caused a marked reduction in nuclear localization and an increase in protein carbonyl formation of NF-kappaB p65 subunit. These results suggest that NO/O2-induced apoptosis occurs by suppressing NF-kappaB activity.
Franek
William R
WR
Department of Thoracic Cardiovascular Surgery, Winthrop University Hospital, State University of New York/Stony Brook School of Medicine, Mineola, New York 11501, USA.
Chowdary
Yalamanchali C
YC
Lin
Xinchun
X
Hu
Maowen
M
Miller
Edmund J
EJ
Kazzaz
Jeffrey A
JA
Razzano
Pasquale
P
Romashko
John
J
Davis
Jonathan M
JM
Narula
Pramod
P
Horowitz
Stuart
S
Scott
William
W
Mantell
Lin L
LL
D016475:3T3 Cells; D000230:Adenocarcinoma; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects; D004357:Drug Synergism; D006367:HeLa Cells; D006801:Humans; D018496:Hyperoxia; D020672:I-kappa B Proteins / Q000187:drug effects / Q000378:metabolism; D008175:Lung Neoplasms; D051379:Mice; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000037:antagonists & inhibitors* / Q000187:drug effects / Q000378:metabolism; D009569:Nitric Oxide / Q000494:pharmacology*; D010100:Oxygen / Q000633:toxicity*; D021122:Protein Subunits; D021381:Protein Transport / Q000187:drug effects; D014407:Tumor Cells, Cultured
D020672:I-kappa B Proteins; D016328:NF-kappa B; C000606204:NFKBIA protein, human; C000606205:Nfkbia protein, mouse; D021122:Protein Subunits; D000072000:NF-KappaB Inhibitor alpha; D009569:Nitric Oxide; C505407:CASP3 protein, human; C505409:Casp3 protein, mouse; D053148:Caspase 3; D020169:Caspases; D010100:Oxygen