Cellular and mitochondrial changes in glutamate-induced HT4 neuronal cell death

O. Tirosh, C. K. Sen*, S. Roy, L. Packer

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

75 Scopus citations

Abstract

Elevated levels of extracellular glutamate are neurotoxic. The cytotoxic property of extracellular glutamate is known to mediate two primary mechanisms, excitotoxicity and excitotoxicity-independent processes. The excitotoxicity-independent pathway was investigated in the current study in a mouse hippocampal-derived HT4 cell line. Exposure of HT4 cells to glutamate for 12h induced loss of cell viability preceded by rapid loss of intracellular reduced glutathione followed by accumulation of intracellular reactive oxygen species, elevation of intracellular Ca2+, progressive loss of mitochondrial membrane potential swelling and loss of mitochondrial outer membrane integrity. Glutamate-induced loss of DNA integrity has been detected. The antioxidants α-tocopherol and trolox, mitochondrial calcium uniporter inhibitor Ruthenium Red and protein synthesis inhibitor cycloheximide all showed protection against glutamate-induced toxicity. None of the protective agents except for α-tocopherol controlled the glutamate-induced reactive oxygen species build-up. However, these cell death regulators prevented the glutamate-induced mitochondrial damage and regulated glutamate-induced increase in intracellular Ca2+. Carbonyl cyanide p-trifluoromethoxyphenyl-hydrazone, a mitochondrial uncoupler, partially protected against glutamate-induced cell death and mitochondrial damage, while the mitochondrial ribosomal inhibitor chloramphenicol and extracellular Ca2+ chelator ethylene glycol-bis(β-aminoethyl ether)-N,N,N',N'-tetraacetic acid did not protect the cells against glutamate treatment.The results of this study demonstrated that mitochondrial dysfunction was a key event in the excitotoxicity-independent component of neuronal cell death. Reactive oxygen species accumulation and glutathione depletion were prominent in glutamate-treated cells; however, these events were not direct mediators of cell death. Copyright (C) 2000 Elsevier Science Ltd.

Original languageAmerican English
Pages (from-to)531-541
Number of pages11
JournalNeuroscience
Volume97
Issue number3
DOIs
StatePublished - May 2000
Externally publishedYes

Bibliographical note

Funding Information:
We thank Dr John Maguire and Dr Kishorchandra Gohil for their valuable suggestions for preparation of the manuscript. This research was supported by NIH grants DK50430 (to L. P.) and GM27345 (to C. K. S.) and also by the Alice Sussman fund of the Hebrew University of Jerusalem, Israel.

Keywords

  • Antioxidants
  • Intracellular calcium
  • Protein synthesis
  • Reactive oxygen species
  • Redox

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