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Opposing roles for caspase and calpain death proteases in L-glutamate-induced oxidative neurotoxicity.
Toxicol Appl Pharmacol. 2008 Oct 15; 232(2):258-67.TA

Abstract

Oxidative glutamate toxicity in HT22 murine hippocampal cells is a model for neuronal death by oxidative stress. We have investigated the role of proteases in HT22 cell oxidative glutamate toxicity. L-glutamate-induced toxicity was characterized by cell and nuclear shrinkage and chromatin condensation, yet occurred in the absence of either DNA fragmentation or mitochondrial cytochrome c release. Pretreatment with the selective caspase inhibitors either benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone (pan-caspase), N-acetyl-Leu-Glu-His-Asp-aldehyde (caspase 9) or N-acetyl-Ile-Glu-Thr-Asp-aldehyde (caspase 8), significantly increased L-glutamate-induced cell death with a corresponding increase in observed nuclear shrinkage and chromatin condensation. This enhancement of glutamate toxicity correlated with an increase in L-glutamate-dependent production of reactive oxygen species (ROS) as a result of caspase inhibition. Pretreating the cells with N-acetyl-L-cysteine prevented ROS production, cell shrinkage and cell death from L-glutamate as well as that associated with the presence of the pan-caspase inhibitor. In contrast, the caspase-3/-7 inhibitor N-acetyl-Asp-Glu-Val-Asp aldehyde was without significant effect. However, pretreating the cells with the calpain inhibitor N-acetyl-Leu-Leu-Nle-CHO, but not the cathepsin B inhibitor CA-074, prevented cell death. The cytotoxic role of calpains was confirmed further by: 1) cytotoxic dependency on intracellular Ca(2+) increase, 2) increased cleavage of the calpain substrate Suc-Leu-Leu-Val-Tyr-AMC and 3) immunoblot detection of the calpain-selective 145 kDa alpha-fodrin cleavage fragment. We conclude that oxidative L-glutamate toxicity in HT22 cells is mediated via calpain activation, whereas inhibition of caspases-8 and -9 may exacerbate L-glutamate-induced oxidative neuronal damage through increased oxidative stress.

Authors+Show Affiliations

Division of Biochemical Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford, GU2 7XH, UK.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

18687350

Citation

Elphick, Lucy M., et al. "Opposing Roles for Caspase and Calpain Death Proteases in L-glutamate-induced Oxidative Neurotoxicity." Toxicology and Applied Pharmacology, vol. 232, no. 2, 2008, pp. 258-67.
Elphick LM, Hawat M, Toms NJ, et al. Opposing roles for caspase and calpain death proteases in L-glutamate-induced oxidative neurotoxicity. Toxicol Appl Pharmacol. 2008;232(2):258-67.
Elphick, L. M., Hawat, M., Toms, N. J., Meinander, A., Mikhailov, A., Eriksson, J. E., & Kass, G. E. (2008). Opposing roles for caspase and calpain death proteases in L-glutamate-induced oxidative neurotoxicity. Toxicology and Applied Pharmacology, 232(2), 258-67. https://doi.org/10.1016/j.taap.2008.07.008
Elphick LM, et al. Opposing Roles for Caspase and Calpain Death Proteases in L-glutamate-induced Oxidative Neurotoxicity. Toxicol Appl Pharmacol. 2008 Oct 15;232(2):258-67. PubMed PMID: 18687350.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Opposing roles for caspase and calpain death proteases in L-glutamate-induced oxidative neurotoxicity. AU - Elphick,Lucy M, AU - Hawat,Mohammad, AU - Toms,Nick J, AU - Meinander,Annika, AU - Mikhailov,Andrey, AU - Eriksson,John E, AU - Kass,George E N, Y1 - 2008/07/19/ PY - 2007/12/20/received PY - 2008/06/30/revised PY - 2008/07/01/accepted PY - 2008/8/9/pubmed PY - 2008/11/7/medline PY - 2008/8/9/entrez SP - 258 EP - 67 JF - Toxicology and applied pharmacology JO - Toxicol Appl Pharmacol VL - 232 IS - 2 N2 - Oxidative glutamate toxicity in HT22 murine hippocampal cells is a model for neuronal death by oxidative stress. We have investigated the role of proteases in HT22 cell oxidative glutamate toxicity. L-glutamate-induced toxicity was characterized by cell and nuclear shrinkage and chromatin condensation, yet occurred in the absence of either DNA fragmentation or mitochondrial cytochrome c release. Pretreatment with the selective caspase inhibitors either benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone (pan-caspase), N-acetyl-Leu-Glu-His-Asp-aldehyde (caspase 9) or N-acetyl-Ile-Glu-Thr-Asp-aldehyde (caspase 8), significantly increased L-glutamate-induced cell death with a corresponding increase in observed nuclear shrinkage and chromatin condensation. This enhancement of glutamate toxicity correlated with an increase in L-glutamate-dependent production of reactive oxygen species (ROS) as a result of caspase inhibition. Pretreating the cells with N-acetyl-L-cysteine prevented ROS production, cell shrinkage and cell death from L-glutamate as well as that associated with the presence of the pan-caspase inhibitor. In contrast, the caspase-3/-7 inhibitor N-acetyl-Asp-Glu-Val-Asp aldehyde was without significant effect. However, pretreating the cells with the calpain inhibitor N-acetyl-Leu-Leu-Nle-CHO, but not the cathepsin B inhibitor CA-074, prevented cell death. The cytotoxic role of calpains was confirmed further by: 1) cytotoxic dependency on intracellular Ca(2+) increase, 2) increased cleavage of the calpain substrate Suc-Leu-Leu-Val-Tyr-AMC and 3) immunoblot detection of the calpain-selective 145 kDa alpha-fodrin cleavage fragment. We conclude that oxidative L-glutamate toxicity in HT22 cells is mediated via calpain activation, whereas inhibition of caspases-8 and -9 may exacerbate L-glutamate-induced oxidative neuronal damage through increased oxidative stress. SN - 1096-0333 UR - https://www.unboundmedicine.com/medline/citation/18687350/Opposing_roles_for_caspase_and_calpain_death_proteases_in_L_glutamate_induced_oxidative_neurotoxicity_ DB - PRIME DP - Unbound Medicine ER -