KMID : 0880520170530030196
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Chonnam Medical Journal 2017 Volume.53 No. 3 p.196 ~ p.202
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NADPH Oxidase Mediates ¥â-Amyloid Peptide-Induced Neuronal Death in Mouse Cortical Cultures
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Chay Kee-Oh
Nam Kyoung-Young Hwang Shi-Nae Kim Jong-Keun Bae Choon-Sang
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Abstract
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¥â-Amyloid peptide (A¥â) is the main component of senile plaques in patients with Alzheimer's disease, and is known to be a main pathogenic factor of the disease. Recent evidence indicates that activation of NADPH oxidase (NOX) in microglia or astrocytes may be a source of A¥â-induced reactive oxygen species (ROS). We investigated the role of neuronal NOX in A¥â-induced neuronal death in mouse mixed cortical cultures. Cell death was assessed by measuring lactate dehydrogenase efflux to bathing media 24 or 48 hr after exposure to A¥â25-35, a fragment of A¥â with an equivalent neurotoxic effect. A¥â25-35 induced neuronal death in concentration- and time- dependent manners with apoptotic features. Neuronal death was significantly attenuated, not only by anti-apoptotic drugs, such as z-VAD-fmk and cycloheximide, but also by antioxidants, such as trolox, ascorbic acid, and epigallocatethin gallate. We also demonstrated that treatment with 20 ¥ìM A¥â25-35 increased fluorescent signals in mixed cortical cultures, but produced only weak signals in pure astrocyte cultures in the presence of 2',7'-dichlorofluorescin diacetate (DCF-DA), an indicator for intracellular ROS. Increased DCF-DA fluorescence was markedly inhibited, not only by trolox, but also by selective NOX inhibitors, such as apocynin and AEBSF. Western blot analyses revealed that A¥â25-35 increased the expression of gp91phox, a main subunit of NOX in cells. The above antioxidants, apocynin, and AEBSF significantly attenuated neuronal death induced by A¥â25-35. Furthermore, the gp91phox-specific siRNA-based knockdown of NOX significantly inhibited neuronal death. These results suggest that activation of neuronal NOX is involved in A¥â25-35-induced neuronal death.
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KEYWORD
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Amyloid beta-Peptides, Alzheimer Disease, NADPH Oxidase, Reactive Oxygen Species
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