Glutamate-induced oxidative stress, but not cell death, is largely dependent upon extracellular calcium in mouse neuronal HT22 cells.
Elucidating the relationship of glutamate-induced Ca2+ flux and oxidative death of neuronal cells may be of great relevance for neurodegenerative diseases in human beings. Mouse hippocampal HT22 cells provide a model system to study this relationship at the molecular level. Here we show that stimulation of HT22 cells with 5 mM glutamate is cytotoxic. Glutamate-induced cytotoxicity was associated with the generation of reactive oxygen species (ROS) and activation of the death executioner caspases 1 and 3. Treatment of HT22 cells with the calcium chelator, EGTA, and the calcium channel blocker, CoCl2, revealed that glutamate-induced cell death was dependent, in part, on glutamate-induced Ca2+ influx from extracellular stores. However, activation of caspases 1 and 3 and death of HT22 cells were also observed when Ca2+ was lacking in the extracellular milieu and ROS production abrogated. These findings led us to conclude that glutamate-induced death of mouse HT22 cells utilizes a complex mechanism that relies only in part on Ca2+ influx and ROS production. Additional studies are warranted to evaluate glutamate-induced death mechanisms that operate independently of Ca2+ influx and generation of ROS.
Ha
Jong Seong
JS
Systemic Proteomics Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 52 Oun, Yusong, Taejon 305-333, South Korea.
Park
Sung Sup
SS
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002122:Calcium Chloride / Q000494:pharmacology; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002452:Cell Count / Q000379:methods; D016923:Cell Death / Q000187:drug effects; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D002614:Chelating Agents / Q000494:pharmacology; D003035:Cobalt / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004533:Egtazic Acid / Q000494:pharmacology; D005110:Extracellular Space / Q000187:drug effects / Q000378:metabolism*; D018698:Glutamic Acid / Q000494:pharmacology*; D051379:Mice; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D009842:Oligopeptides / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects*; D017382:Reactive Oxygen Species / Q000378:metabolism
D002614:Chelating Agents; D009842:Oligopeptides; D017382:Reactive Oxygen Species; C099158:acetyl-aspartyl-glutamyl-valyl-aspartal; D003035:Cobalt; D018698:Glutamic Acid; D004533:Egtazic Acid; C505407:CASP3 protein, human; C505409:Casp3 protein, mouse; D053148:Caspase 3; D020169:Caspases; C018021:cobaltous chloride; D002122:Calcium Chloride; D002118:Calcium