biostudies-literatureGao TAlzheimer’s AssociationNIA NIH HHSGeorgia Clinical & Translational Science Alliance of the NIHNINDS NIH HHSNIHGeorgia Clinical &amp; Translational Science Alliance of the NIHAlzheimer's AssociationVA MERIT AwardNIH HHS116https://www.ebi.ac.uk/biostudies/studies/S-EPMC6545199biostudies-literatureUnknown16(1)<h4>Background</h4>Microglia and CNS-infiltrating monocytes/macrophages (CNS-MPs) perform pro-inflammatory and protective anti-inflammatory functions following ischemic stroke. Selective inhibition of pro-inflammatory responses can be achieved by Kv1.3 channel blockade, resulting in a lower infarct size in the transient middle cerebral artery occlusion (tMCAO) model. Whether beneficial effects of Kv1.3 blockers are mediated by targeting microglia or CNS-infiltrating monocytes/macrophages remains unclear.<h4>Methods</h4>In the 30-min tMCAO mouse model, we profiled functional cell-surface Kv1.3 channels and phagocytic properties of acutely isolated CNS-MPs at various timepoints post-reperfusion. Kv1.3 channels were flow cytometrically detected using fluorescein-conjugated Kv1.3-binding peptide ShK-F6CA as well as by immunohistochemistry. Quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR) was performed to measure Kv1.3 (Kcna3) and Kir2.1 (Kcnj2) gene expression. Phagocytosis of 1-μm microspheres by acutely isolated CNS-MPs was measured by flow cytometry.<h4>Results</h4>In flow cytometric assays, Kv1.3 channel expression by CD11b⁺ CNS-MPs was increased between 24 and 72 h post-tMCAO and decreased by 7 days post-tMCAO. Increased Kv1.3 expression was restricted to CD11b⁺CD45^lowLy6c^low (microglia) and CD11b⁺CD45^highLy6C^low CNS-MPs but not CD11b⁺CD45^highLy6c^high inflammatory monocytes/macrophages. In immunohistochemical studies, Kv1.3 protein expression was increased in Iba1⁺ microglia at 24-48 h post-tMCAO. No change in Kv1.3 mRNA in CNS-MPs was observed following tMCAO.<h4>Conclusions</h4>We conclude that resident microglia and a subset of CD45^highLy6c^low CNS-MPs are the likely cellular targets of Kv1.3 blockers and the delayed phase of neuroinflammation is the optimal therapeutic window for Kv1.3 blockade in ischemic stroke.Journal of neuroinflammationTemporal profiling of Kv1.3 channel expression in brain mononuclear phagocytes following ischemic stroke.PMC6545199K08 NS099474AARG 37102K08-NS099474-1NS-091201P50 AG025688UL1TR002378P51 OD011132NS-079331IO1BX003441Raza SAYepes MRangaraju SNwabueze NVXiao HCheng LRamesha STomkins AJGao TfalseTemporal profiling of Kv1.3 channel expression in brain mononuclear phagocytes following ischemic stroke.<h4>Background</h4>Microglia and CNS-infiltrating monocytes/macrophages (CNS-MPs) perform pro-inflammatory and protective anti-inflammatory functions following ischemic stroke. Selective inhibition of pro-inflammatory responses can be achieved by Kv1.3 channel blockade, resulting in a lower infarct size in the transient middle cerebral artery occlusion (tMCAO) model. Whether beneficial effects of Kv1.3 blockers are mediated by targeting microglia or CNS-infiltrating monocytes/macrophages remains unclear.<h4>Methods</h4>In the 30-min tMCAO mouse model, we profiled functional cell-surface Kv1.3 channels and phagocytic properties of acutely isolated CNS-MPs at various timepoints post-reperfusion. Kv1.3 channels were flow cytometrically detected using fluorescein-conjugated Kv1.3-binding peptide ShK-F6CA as well as by immunohistochemistry. Quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR) was performed to measure Kv1.3 (Kcna3) and Kir2.1 (Kcnj2) gene expression. Phagocytosis of 1-μm microspheres by acutely isolated CNS-MPs was measured by flow cytometry.<h4>Results</h4>In flow cytometric assays, Kv1.3 channel expression by CD11b⁺ CNS-MPs was increased between 24 and 72 h post-tMCAO and decreased by 7 days post-tMCAO. Increased Kv1.3 expression was restricted to CD11b⁺CD45^lowLy6c^low (microglia) and CD11b⁺CD45^highLy6C^low CNS-MPs but not CD11b⁺CD45^highLy6c^high inflammatory monocytes/macrophages. In immunohistochemical studies, Kv1.3 protein expression was increased in Iba1⁺ microglia at 24-48 h post-tMCAO. No change in Kv1.3 mRNA in CNS-MPs was observed following tMCAO.<h4>Conclusions</h4>We conclude that resident microglia and a subset of CD45^highLy6c^low CNS-MPs are the likely cellular targets of Kv1.3 blockers and the delayed phase of neuroinflammation is the optimal therapeutic window for Kv1.3 blockade in ischemic stroke.2019-01-01T00:00:00Z2019 Jun2025-04-04T18:59:05.508Z2019-07-24T07:08:06ZS-EPMC65451993115337710.1186/s12974-019-1510-8