Poly(ADP-ribose)polymerase activation mediates lung epithelial cell death in vitro but is not essential in hyperoxia-induced lung injury.
Hyperoxia induces extensive DNA damage and lung cell death by apoptotic and nonapoptotic pathways. We analyzed the regulation of Poly(ADP-ribose)polymerase-1 (PARP-1), a nuclear enzyme activated by DNA damage, and its relation to cell death during hyperoxia in vitro and in vivo. In lung epithelial-derived A549 cells, which are known to die by necrosis when exposed to oxygen, a minimal amount of PARP-1 was cleaved, correlating with the absence of active caspase-3. Conversely, in primary lung fibroblasts, which die mainly by apoptosis, the complete cleavage of PARP-1 was concomitant to the induction of active caspase-3, as assessed by Western blot and caspase activity. Blockade of caspase activity by Z-VAD reduced the amount of cleaved PARP-1 in fibroblasts. Hyperoxia induced PARP activity in both cell types, as revealed by poly-ADP-ribose accumulation. In A549 cells, the final outcome of necrosis was dependent on PARP activity because it was prevented by the PARP inhibitor 3-aminobenzamide. In contrast, apoptosis of lung fibroblasts was not sensitive to 3-aminobenzamide and was not affected by PARP-1 deletion. In vivo, despite evidence of PARP activation in hyperoxia-exposed mouse lungs, absence of PARP-1 did not change the extent of lung damage, arguing for redundant oxidative stress-induced cell death pathways.
Pagano
Alessandra
A
Departments of Pediatrics and Pathology, Centre Médical Universitaire, 1 rue Michel Servet, 1211 Geneva 4, Switzerland.
Pitteloud
Claire
C
Reverdin
Coralie
C
Métrailler-Ruchonnet
Isabelle
I
Donati
Yves
Y
Barazzone Argiroffo
Constance
C
D000818:Animals; D017209:Apoptosis; D001549:Benzamides / Q000494:pharmacology; D015153:Blotting, Western; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D045744:Cell Line, Tumor; D004789:Enzyme Activation; D004847:Epithelial Cells / Q000201:enzymology / Q000473:pathology*; D005347:Fibroblasts / Q000201:enzymology / Q000473:pathology; D006801:Humans; D018496:Hyperoxia / Q000201:enzymology*; D066298:In Vitro Techniques; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008168:Lung / Q000201:enzymology / Q000473:pathology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism*; D011650:Pulmonary Alveoli / Q000166:cytology / Q000378:metabolism
D001549:Benzamides; C025160:3-aminobenzamide; D007770:L-Lactate Dehydrogenase; C499320:PARP1 protein, human; C499321:Parp1 protein, mouse; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases; C505407:CASP3 protein, human; C505409:Casp3 protein, mouse; D053148:Caspase 3; D020169:Caspases