Voltage‐gated sodium channel Nav1.5 contributes to astrogliosis in an in vitro model of glial injury via reverse Na+/Ca2+ exchange |
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Authors: | Joel A Black Stephen G Waxman |
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Institution: | 1. Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut;2. Rehabilitation Research Center, VA Connecticut Healthcare System, West Haven, Connecticut |
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Abstract: | Astrogliosis is a prominent feature of many, if not all, pathologies of the brain and spinal cord, yet a detailed understanding of the underlying molecular pathways involved in the transformation from quiescent to reactive astrocyte remains elusive. We investigated the contribution of voltage‐gated sodium channels to astrogliosis in an in vitro model of mechanical injury to astrocytes. Previous studies have shown that a scratch injury to astrocytes invokes dual mechanisms of migration and proliferation in these cells. Our results demonstrate that wound closure after mechanical injury, involving both migration and proliferation, is attenuated by pharmacological treatment with tetrodotoxin (TTX) and KB‐R7943, at a dose that blocks reverse mode of the Na+/Ca2+ exchanger (NCX), and by knockdown of Nav1.5 mRNA. We also show that astrocytes display a robust Ca2+]i transient after mechanical injury and demonstrate that this Ca2+]i response is also attenuated by TTX, KB‐R7943, and Nav1.5 mRNA knockdown. Our results suggest that Nav1.5 and NCX are potential targets for modulation of astrogliosis after injury via their effect on Ca2+]i. GLIA 2014;62:1162–1175 |
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Keywords: | glial scar sodium channels sodium– calcium exchanger migration proliferation |
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