The role of NADPH oxidase and neuronal nitric oxide synthase in zinc-induced poly(ADP-ribose) polymerase activation and cell death in cortical culture.
In the present study, we examined the role and the mechanism of poly(ADP-ribose) polymerase (PARP) and poly(ADP-ribose) glycohydrolase (PARG) activation in zinc-induced cell death in cortical culture. After brief exposure to 400 microM zinc, cortical cells exhibited DNA fragmentation, increased poly(ADP-ribosyl)ation, and decreased levels of nicotinamide adenine dinucleotide (NAD) and ATP and subsequently underwent cell death. Inhibitors of PARP/PARG attenuated both zinc-induced NAD/ATP depletion and cell death, thereby implicating the PARP/PARG cascade in these processes. The zinc-inducible enzymes NADPH oxidase and neuronal nitric oxide synthase (nNOS) contributed to PARP activation as their inhibitors attenuated zinc-induced poly(ADP-ribosyl)ation. Levels of nitric oxide and nitrites increased following zinc exposure, consistent with NOS activation. In addition, Western blots and RT-PCR analysis revealed that protein and mRNA levels of nNOS specifically increased following zinc exposure in a manner similar to that of NADPH oxidase. The present study demonstrates that induction of NADPH oxidase and nNOS actively contributes to PARP/PARG-mediated NAD/ATP depletion and cell death induced by zinc in cortical culture.
Kim
Yang-Hee
YH
National Creative Research Initiative Center for the Study of CNS Zinc, Department of Neurology, University of Ulsan College of Medicine, Seoul, 138-736, Korea.
Koh
Jae-Young
JY
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology; D001253:Astrocytes / Q000166:cytology / Q000187:drug effects / Q000201:enzymology; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology / Q000187:drug effects* / Q000196:embryology / Q000201:enzymology; D018920:Coculture Techniques; D053938:DNA Fragmentation / Q000187:drug effects; D004789:Enzyme Activation / Q000187:drug effects; D004790:Enzyme Induction / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006026:Glycoside Hydrolases / Q000037:antagonists & inhibitors / Q000378:metabolism; D051379:Mice; D009243:NAD / Q000378:metabolism; D019255:NADPH Oxidases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000201:enzymology; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D052248:Nitric Oxide Synthase Type I; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism*; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000378:metabolism; D015032:Zinc / Q000633:toxicity*
D004791:Enzyme Inhibitors; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D009243:NAD; D009569:Nitric Oxide; C002744:3-nitrotyrosine; D014443:Tyrosine; D000255:Adenosine Triphosphate; D019001:Nitric Oxide Synthase; D052248:Nitric Oxide Synthase Type I; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; C496321:Nos1 protein, mouse; C496317:Nos2 protein, mouse; C496315:Nos3 protein, mouse; D019255:NADPH Oxidases; D011065:Poly(ADP-ribose) Polymerases; D006026:Glycoside Hydrolases; C022407:poly ADP-ribose glycohydrolase; D015032:Zinc