Abstract
BackgroundReactive astrogliosis is one of the significantly pathological features in ischemic stroke accompanied with changes in gene expression, morphology, and proliferation. KCa3.1 was involved in TGF-β-induced astrogliosis in vitro and also contributed to astrogliosis-mediated neuroinflammation in neurodegeneration disease.MethodsWild type mice and KCa3.1−/− mice were subjected to permanent middle cerebral artery occlusion (pMCAO) to evaluate the infarct areas by 2,3,5-triphenyltetrazolium hydrochloride staining and neurological deficit. KCa3.1 channels expression and cell localization in the brain of pMCAO mice model were measured by immunoblotting and immunostaining. Glia activation and neuron loss was measured by immunostaining. DiBAC4 (3) and Fluo-4AM were used to measure membrane potential and cytosolic Ca2+ level in oxygen-glucose deprivation induced reactive astrocytes in vitro.ResultsImmunohistochemistry on pMCAO mice infarcts showed strong upregulation of KCa3.1 immunoreactivity in reactive astrogliosis. KCa3.1−/− mice exhibited significantly smaller infarct areas on pMCAO and improved neurological deficit. Both activated gliosis and neuronal loss were attenuated in KCa3.1−/− pMCAO mice. In the primary cultured astrocytes, the expressions of KCa3.1 and TRPV4 were increased associated with upregulation of astrogliosis marker GFAP induced by oxygen-glucose deprivation. The activation of KCa3.1 hyperpolarized membrane potential and, by promoting the driving force for calcium, induced calcium entry through TRPV4, a cation channel of the transient receptor potential family. Double-labeled staining showed that KCa3.1 and TRPV4 channels co-localized in astrocytes. Blockade of KCa3.1 or TRPV4 inhibited the phenotype switch of reactive astrogliosis.ConclusionsOur data suggested that KCa3.1 inhibition might represent a promising therapeutic strategy for ischemia stroke.
Highlights
Reactive astrogliosis is one of the significantly pathological features in ischemic stroke accompanied with changes in gene expression, morphology, and proliferation
Upregulation of KCa3.1 expression in the brains of permanent middle cerebral artery occlusion (pMCAO) mice Most recently, we reported KCa3.1 was increased in reactive astrocytes in the brains of both mouse models of Alzheimer’s disease (AD) and AD patients, and pharmacological inhibition or genetic deletion of KCa3.1 reduced astrogliosis-induced neuronal loss in the AD mouse model [7]
(See figure on previous page.) Fig. 5 Role of transient receptor potential vanilloid 4 (TRPV4) and KCa3.1 in alteration of membrane potential and Ca2+ entry in astrocytes following OGD. a–f Changes in membrane potential in response to activation of KCa3.1 channels and TRPV4 channels in astrocytes exposed to OGD 1 h. a, b 1-EBIO was added to wild type (WT) astrocytes and membrane potential measured with or without OGD or HC 067047
Summary
Reactive astrogliosis is one of the significantly pathological features in ischemic stroke accompanied with changes in gene expression, morphology, and proliferation. KCa3.1 channels expression and cell localization in the brain of pMCAO mice model were measured by immunoblotting and immunostaining. We reported that KCa3.1 was increased in reactive astrocytes as well as neurons in the brains of both mouse models of AD and AD patients. In a mouse model of ischemia, genetic deletion and wild type mice treated with the KCa3.1 blocker TRAM-34 resulted in a decrease in infarct areas and improved neurological deficits [9]. These findings suggest that KCa3.1 channels are important in the process of stroke, and that their blockade might prove useful as therapy in stroke with upregulated KCa3.1 expression
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
