Oxidative stress response results in increased p21WAF1/CIP1 degradation in cystic fibrosis lung epithelial cells.
Lung epithelium in cystic fibrosis (CF) patients is characterized by structural damage and altered repair due to oxidative stress. To gain insight into the oxidative stress-related damage in CF, we studied the effects of hyperoxia in CF and normal lung epithelial cell lines. In response to a 95% O2 exposure, both cell lines exhibited increased reactive oxygen species. Unexpectedly, the cyclin-dependent kinase inhibitor p21WAF1/CIP1 protein was undetectable in CF cells under hyperoxia, contrasting with increased levels of p21WAF1/CIP1 in normal cells. In both cell lines, exposure to hyperoxia led to S-phase arrest. Apoptotic features including nuclear condensation, DNA laddering, Annexin V incorporation, and elevated caspase-3 activity were not readily observed in CF cells in contrast to normal cells. Interestingly, treatment of hyperoxia-exposed CF cells with two proteasome inhibitors, MG132 and lactacystin, restored p21WAF1/CIP1 protein and was associated with an increase of caspase-3 activity. Moreover, transfection of p21WAF1/CIP1 protein in CF cells led to increased caspase-3 activity and was associated with increased apoptotic cell death, specifically under hyperoxia. Taken together, our data suggest that modulating p21WAF1/CIP1 degradation may have the therapeutic potential of reducing lung epithelial damage related to oxidative stress in CF patients.
Boncoeur
Emilie
E
Inserm U719, Université Pierre et Marie Curie, Hôpital Saint-Antoine, 184 rue du Fg St Antoine, Bâtiment Kourilsky, 75571 Paris Cedex 12, France.
Tabary
Olivier
O
Bonvin
Elise
E
Muselet
Celine
C
Fritah
Asmaa
A
Lefait
Emilie
E
Redeuilh
Gerard
G
Clement
Annick
A
Jacquot
Jacky
J
Henrion-Caude
Alexandra
A
D000111:Acetylcysteine / Q000031:analogs & derivatives / Q000494:pharmacology; D017304:Annexin A5 / Q000378:metabolism; D017209:Apoptosis; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002478:Cells, Cultured; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000235:genetics / Q000378:metabolism*; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D003550:Cystic Fibrosis / Q000201:enzymology* / Q000473:pathology; D004847:Epithelial Cells / Q000201:enzymology / Q000473:pathology; D006801:Humans; D018496:Hyperoxia / Q000201:enzymology; D007976:Leupeptins / Q000494:pharmacology; D008168:Lung / Q000201:enzymology* / Q000473:pathology; D018384:Oxidative Stress; D010100:Oxygen / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D016196:S Phase
D017304:Annexin A5; D050759:Cyclin-Dependent Kinase Inhibitor p21; D015853:Cysteine Proteinase Inhibitors; D007976:Leupeptins; D017382:Reactive Oxygen Species; C067713:lactacystin; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases; C072553:benzyloxycarbonylleucyl-leucyl-leucine aldehyde; D010100:Oxygen; D000111:Acetylcysteine