Sequential release of nitric oxide, zinc, and superoxide in hypoglycemic neuronal death.
Oxidative stress and zinc release are both known to contribute to neuronal death after hypoglycemia; however, the cause-effect relationships between these events are not established. Here we found, using a rat model of profound hypoglycemia, that the neuronal zinc release and translocation that occur immediately after hypoglycemia are prevented by the nitric oxide synthase inhibitor 7-nitroindazole but not by overexpression of superoxide dismutase-1 (SOD-1). However, overexpression of SOD-1 prevented activation of poly(ADP-ribose) polymerase-1 (PARP-1) and neuronal death, suggesting that zinc release is upstream of superoxide production. Accordingly, zinc-induced superoxide production was blocked in neuronal cultures by the NADPH oxidase inhibitor apocynin and by genetic deficiency in the p47(phox) subunit of NADPH oxidase. A key role for the vesicular zinc pool in this process was suggested by reduced superoxide formation and neuronal death in mice deficient in zinc transporter 3. Together, these findings suggest a series of events in which nitric oxide production triggers vesicular zinc release, which in turn activates NADPH oxidase and PARP-1. This sequence may also occur in other central nervous system disorders in which zinc, nitric oxide, and oxidative stress have been linked.
Suh
Sang Won
SW
Department of Neurology, Veterans Affairs Medical Center, University of California, San Francisco, California 94121, USA. sang.suh@ucsf.edu
Hamby
Aaron M
AM
Gum
Elizabeth T
ET
Shin
Byung Seop
BS
Won
Seok Joon
SJ
Sheline
Christian T
CT
Chan
Pak H
PH
Swanson
Raymond A
RA
D000818:Animals; D030801:Animals, Genetically Modified; D002352:Carrier Proteins / Q000378:metabolism; D027682:Cation Transport Proteins / Q000378:metabolism; D016923:Cell Death / Q000502:physiology*; D002478:Cells, Cultured; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005947:Glucose / Q000494:pharmacology; D007003:Hypoglycemia / Q000150:complications / Q000378:metabolism / Q000473:pathology*; D008565:Membrane Proteins / Q000378:metabolism; D026901:Membrane Transport Proteins; D051379:Mice; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D019255:NADPH Oxidases / Q000235:genetics / Q000378:metabolism; D009474:Neurons / Q000378:metabolism / Q000473:pathology*; D009569:Nitric Oxide / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000378:metabolism; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism; D000072105:Superoxide Dismutase-1; D013481:Superoxides / Q000378:metabolism*; D015032:Zinc / Q000378:metabolism*
D002352:Carrier Proteins; D027682:Cation Transport Proteins; D004791:Enzyme Inhibitors; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; C491177:Slc30a3 protein, mouse; C503697:zinc transporter 3, rat; D013481:Superoxides; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; C000606291:Sod1 protein, mouse; C000606292:Sod1 protein, rat; D013482:Superoxide Dismutase; D000072105:Superoxide Dismutase-1; D019255:NADPH Oxidases; C060505:neutrophil cytosolic factor 1; C499321:Parp1 protein, mouse; C499322:Parp1 protein, rat; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases; D005947:Glucose; D015032:Zinc