title: Induction of neuronal apoptosis by thiol oxidation: putative role of intracellular zinc release.
abstract: The membrane-permeant oxidizing agent 2,2'-dithiodipyridine (DTDP) can induce Zn(2+) release from metalloproteins in cell-free systems. Here, we report that brief exposure to DTDP triggers apoptotic cell death in cultured neurons, detected by the presence of both DNA laddering and asymmetric chromatin formation. Neuronal death was blocked by increased extracellular potassium levels, by tetraethylammonium, and by the broad-spectrum cysteine protease inhibitor butoxy-carbonyl-aspartate-fluoromethylketone. N,N,N', N'-Tetrakis-(2-pyridylmethyl)ethylenediamine (TPEN) and other cell-permeant metal chelators also effectively blocked DTDP-induced toxicity in neurons. Cell death, however, was not abolished by the NMDA receptor blocker MK-801, by the intracellular calcium release antagonist dantrolene, or by high concentrations of ryanodine. DTDP generated increases in fluorescence signals in cultured neurons loaded with the zinc-selective dye Newport Green. The fluorescence signals following DTDP treatment also increased in fura-2- and magfura-2-loaded neurons. These responses were completely reversed by TPEN, consistent with a DTDP-mediated increase in intracellular free Zn(2+) concentrations. Our studies suggest that under conditions of oxidative stress, Zn(2+) released from intracellular stores may contribute to the initiation of neuronal apoptosis.
authors.affiliation: Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261, USA. redox@pitt.edu
authors.forename: E
authors.initials: E
authors.lastname: Aizenman
authors.forename: A K
authors.initials: AK
authors.lastname: Stout
authors.forename: K A
authors.initials: KA
authors.lastname: Hartnett
authors.forename: K E
authors.initials: KE
authors.lastname: Dineley
authors.forename: B
authors.initials: B
authors.lastname: McLaughlin
authors.forename: I J
authors.initials: IJ
authors.lastname: Reynolds
mesh_terms: D015082:2,2'-Dipyridyl / Q000031:analogs & derivatives* / Q000633:toxicity; D000818:Animals; D017209:Apoptosis; D002478:Cells, Cultured; D002614:Chelating Agents / Q000494:pharmacology; D018920:Coculture Techniques; D053938:DNA Fragmentation; D004220:Disulfides / Q000037:antagonists & inhibitors / Q000633:toxicity; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005456:Fluorescent Dyes; D007424:Intracellular Fluid / Q000378:metabolism*; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D016202:N-Methylaspartate / Q000633:toxicity; D009457:Neuroglia / Q000166:cytology / Q000187:drug effects; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D010084:Oxidation-Reduction / Q000187:drug effects; D011188:Potassium / Q000378:metabolism / Q000494:pharmacology; D051381:Rats; D019837:Ryanodine Receptor Calcium Release Channel / Q000378:metabolism; D013438:Sulfhydryl Compounds / Q000378:metabolism*; D013439:Sulfhydryl Reagents / Q000037:antagonists & inhibitors / Q000633:toxicity; D019789:Tetraethylammonium / Q000494:pharmacology; D015032:Zinc / Q000378:metabolism*
chemical_list: D002614:Chelating Agents; D004220:Disulfides; D004791:Enzyme Inhibitors; D005456:Fluorescent Dyes; D019837:Ryanodine Receptor Calcium Release Channel; D013438:Sulfhydryl Compounds; D013439:Sulfhydryl Reagents; C001105:2,2'-dipyridyl disulfide; D015082:2,2'-Dipyridyl; D016202:N-Methylaspartate; D019789:Tetraethylammonium; D007770:L-Lactate Dehydrogenase; D015032:Zinc; D011188:Potassium