The role of NADPH oxidase and neuronal nitric oxide synthase in zinc-induced poly(ADP-ribose) polymerase activation and cell death in cortical culture

Exp Neurol. 2002 Oct;177(2):407-18. doi: 10.1006/exnr.2002.7990.

Abstract

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.

MeSH terms

  • Adenosine Triphosphate / metabolism
  • Animals
  • Apoptosis* / drug effects
  • Apoptosis* / physiology
  • Astrocytes / cytology
  • Astrocytes / drug effects
  • Astrocytes / enzymology
  • Cells, Cultured
  • Cerebral Cortex / cytology
  • Cerebral Cortex / drug effects*
  • Cerebral Cortex / embryology
  • Cerebral Cortex / enzymology
  • Coculture Techniques
  • DNA Fragmentation / drug effects
  • Enzyme Activation / drug effects
  • Enzyme Induction / drug effects
  • Enzyme Inhibitors / pharmacology
  • Glycoside Hydrolases / antagonists & inhibitors
  • Glycoside Hydrolases / metabolism
  • Mice
  • NAD / metabolism
  • NADPH Oxidases / antagonists & inhibitors
  • NADPH Oxidases / metabolism*
  • Neurons / cytology
  • Neurons / drug effects
  • Neurons / enzymology
  • Nitric Oxide / metabolism
  • Nitric Oxide Synthase / antagonists & inhibitors
  • Nitric Oxide Synthase / metabolism*
  • Nitric Oxide Synthase Type I
  • Nitric Oxide Synthase Type II
  • Nitric Oxide Synthase Type III
  • Poly(ADP-ribose) Polymerase Inhibitors
  • Poly(ADP-ribose) Polymerases / metabolism*
  • Tyrosine / analogs & derivatives*
  • Tyrosine / metabolism
  • Zinc / toxicity*

Substances

  • Enzyme Inhibitors
  • Poly(ADP-ribose) Polymerase Inhibitors
  • NAD
  • Nitric Oxide
  • 3-nitrotyrosine
  • Tyrosine
  • Adenosine Triphosphate
  • Nitric Oxide Synthase
  • Nitric Oxide Synthase Type I
  • Nitric Oxide Synthase Type II
  • Nitric Oxide Synthase Type III
  • Nos1 protein, mouse
  • Nos2 protein, mouse
  • Nos3 protein, mouse
  • NADPH Oxidases
  • Poly(ADP-ribose) Polymerases
  • Glycoside Hydrolases
  • poly ADP-ribose glycohydrolase
  • Zinc