Kir4.1 Channel Deficits In NG2-glia Contribute To The Loss Of Myelin In Ischemic Stroke

?Background?The contribution of Kir4.1 channels has been focused mainly on astrocytes,which play important roles in the maintenance of resting membrane pontetial,extracellular K~+uptake,cell volume regulation and facilitation of glutamate uptake in the CNS.Here we report that NG2-glia widely express functional Kir4.1 channels during brain development.In adult hippocampus of the mouse brain,Kir4.1 channels contribute more than 80%of K~+channels inward currents in NG2-glia as shown by using conditional knockout transgenic mice.This large portion of Kir4.1 channel currents exhibiting a deficit in NG2-glia demonstrates an intial response of NG2-glia in a transient ischemic mouse model(tMCAO).Further evidence indicates that Kir4.1deficits in NG2-glia caused a loss of myelin in ischemia through the association with oligodendrocyte-specific protein(OSP/Claudin-11),which unravels a potential therapeutic target in the treatment of ischemic stroke.?Objective?Our study focus on the investigation of the functional impairment of Kir4.1channels in NG2-glia after ischemia and the pathological mechanism of demyelination in the CNS.There are three goals we aim to:(1)Whether NG2-glia functionally express Kir4.1 channels in the adult mouse brain.(2)The impact on the Kir4.1 channels in NG2-glia after ischemia.(3)The relevance between the deficits of Kir4.1 channels and demyelination after ischemia and its potential mechanism underlying.?Methods?By using electrophysiological patch clamp recordings in acute brain slices,RNA-sequencing,immunohistochemistry,Wstern blots and Co-Immunoprecipitation,single cell RT-PCR,FACS,electron microscopy and tMCAO mouse model,we examined the Kir4.1 channels biophysical properties,gene expression of K~+channels family,mRNA and protein expression levels of Kir4.1,protein associations between Kir4.1 and OSP,and morphological changes of myelined axons after ischemia.?Results?1.NG2-glia express Kir4.1(Kcnj10)during early developmental and adult life.2.Kir4.1 channel currents constitute a large portion of inward K~+channel currents in NG2-glia and an initial deficit of Kir4.1 channels in NG2-glia but not astrocytes occurred in a tMCAO mouse model.3.Deficits of Kir4.1 channels in NG2-glia contribute to the myelin loss of axons in tMCAO which is potentially through the association with Olig-specific protein(OSP/Claudin-11).?Conclusion?Our data first systematically presented that NG2-glia functionally express Kir4.1in adult mouse brain and the impairment of myelin in axons was mainly caused by the deficits of Kir4.1 in NG2-glia after ischemia through the association with Olig-specific protein(OSP/Claudin-11).Our data also support that Kir4.1 is crucial to the myelin formation during early brain development.