title: Diethylmaleate and iodoacetate in combination caused profound cell death in astrocytes.
abstract: Energy failure and oxidative stress have been implicated in the pathogenesis of ischemia. Here, we report a potential link between cytosolic phospholipase A₂ (cPLA₂) activation and energy failure/oxidative stress-induced astrocyte damage involving reactive oxygen species (ROS), protein kinase C-α (PKC-α), Src, Raf, and extracellular signal-regulated kinase (ERK) signaling and concurrent elevation of endogenous chelatable zinc. Energy failure and oxidative stress were produced by treating astrocytes with glycolytic inhibitor iodoacetate and glutathione chelator diethylmaleate, respectively. Diethylmaleate and iodoacetate in combination caused augmented damage to astrocytes in a time- and concentration-dependent manner. The cell death caused by diethylmaleate/iodoacetate was accompanied by increased ROS generation, PKC-α membrane translocation, Src, Raf, ERK, and cPLA₂ phosphorylation. Pharmacological studies revealed that these activations all contributed to diethylmaleate/iodoacetate-induced astrocyte death. Intriguingly, the mobilization of endogenous chelatable zinc was observed in diethylmaleate/iodoacetate-treated astrocytes. Zinc appears to act as a downstream mediator in response to diethylmaleate/iodoacetate treatment because of the attenuating effects of its chelator N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine. These observations indicate that ROS/PKC-α, Src/Raf/ERK signaling and cPLA₂ are active participants in diethylmaleate/iodoacetate-induced astrocyte death and contribute to a vicious cycle between the depletion of ATP/glutathione and the mobilization of chelatable zinc as critical upstream effectors in initiating cytotoxic cascades.
authors: Department of Education and Research, Taichung Veterans General Hospital, Taichung, Taiwan.
authors: Su-Lan
authors: SL
authors: Liao
authors: Yen-Chuan
authors: YC
authors: Ou
authors: Cheng-Yi
authors: CY
authors: Chang
authors: Wen-Ying
authors: WY
authors: Chen
authors: Yu-Hsiang
authors: YH
authors: Kuan
authors: Wen-Yi
authors: WY
authors: Wang
authors: Hung-Chuan
authors: HC
authors: Pan
authors: Chun-Jung
authors: CJ
authors: Chen
mesh_terms: D000255:Adenosine Triphosphate / Q000502:physiology; D000477:Alkylating Agents / Q000494:pharmacology*; D000818:Animals; D001253:Astrocytes / Q000187:drug effects*; D015153:Blotting, Western; D016923:Cell Death / Q000187:drug effects*; D002614:Chelating Agents / Q000494:pharmacology; D004789:Enzyme Activation / Q000502:physiology; D006019:Glycolysis / Q000187:drug effects; D007461:Iodoacetates / Q000494:pharmacology*; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008297:Male; D008298:Maleates / Q000494:pharmacology*; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism / Q000502:physiology; D018384:Oxidative Stress / Q000187:drug effects; D054467:Phospholipases A2 / Q000378:metabolism; D011493:Protein Kinase C / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species; D015032:Zinc / Q000378:metabolism; D019061:src-Family Kinases / Q000502:physiology
chemical_list: D000477:Alkylating Agents; D002614:Chelating Agents; D007461:Iodoacetates; D008298:Maleates; D017382:Reactive Oxygen Species; D000255:Adenosine Triphosphate; D007770:L-Lactate Dehydrogenase; D019061:src-Family Kinases; D011493:Protein Kinase C; D020928:Mitogen-Activated Protein Kinases; D054467:Phospholipases A2; C014476:diethyl maleate; D015032:Zinc
keywords: astrocyte; energy failure; oxidative stress; zinc