Downregulation of GABA_A Receptor Recycling Mediated by HAP1 Contributes to Neuronal Death in In Vitro Brain Ischemia

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• 作者：Miranda Mele ; Maria Cristina Aspromonte ; Carlos B. Duarte
• 关键词：Huntingtin ; associated protein 1 (HAP1) ; Cerebral ischemia ; GABAA receptors ; Receptor traffic ; Oxygen/glucose deprivation (OGD)
• 刊名：Molecular Neurobiology
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：54
• 期：1
• 页码：45-57
• 全文大小：
• 刊物主题：Neurosciences; Neurobiology; Cell Biology; Neurology;
• 出版者：Springer US
• ISSN：1559-1182
• 卷排序：54

文摘

Downregulation of GABAergic synaptic transmission contributes to the increase in overall excitatory activity in the ischemic brain. A reduction of GABA_A receptor (GABA_AR) surface expression partly accounts for this decrease in inhibitory activity, but the mechanisms involved are not fully elucidated. In this work, we investigated the alterations in GABA_AR trafficking in cultured rat hippocampal neurons subjected to oxygen/glucose deprivation (OGD), an in vitro model of global brain ischemia, and their impact in neuronal death. The traffic of GABA_AR was evaluated after transfection of hippocampal neurons with myc-tagged GABA_AR β3 subunits. OGD decreased the rate of GABA_AR β3 subunit recycling and reduced the interaction of the receptors with HAP1, a protein involved in the recycling of the receptors. Furthermore, OGD induced a calpain-mediated cleavage of HAP1. Transfection of hippocampal neurons with HAP1A or HAP1B isoforms reduced the OGD-induced decrease in surface expression of GABA_AR β3 subunits, and HAP1A maintained the rate of receptor recycling. Furthermore, transfection of hippocampal neurons with HAP1 significantly decreased OGD-induced cell death. These results show a key role for HAP1 protein in the downmodulation of GABAergic neurotransmission during cerebral ischemia, which contributes to neuronal demise.