title: Role for microglia in sex differences after ischemic stroke: importance of M2.
abstract: Inflammation plays a critical role in the pathogenesis of ischemic stroke. This process depends, in part, upon proinflammatory factors released by activated resident central nervous system (CNS) microglia (MG). Previous studies demonstrated that transfer of IL-10(+) B-cells reduced infarct volumes in male C57BL/6 J recipient mice when given 24 h prior to or therapeutically at 4 or 24 h after experimental stroke induced by 60 min middle cerebral artery occlusion (MCAO). The present study assesses possible sex differences in immunoregulation by IL-10(+) B-cells on primary male vs. female MG cultured from naïve and ischemic stroke-induced mice. Thus, MG cultures were treated with recombinant (r)IL-10, rIL-4 or IL-10(+) B-cells after lipopolysaccharide (LPS) activation and evaluated by flow cytometry for production of proinflammatory and anti-inflammatory factors. We found that IL-10(+) B-cells significantly reduced MG production of TNF-α, IL-1β and CCL3 post-MCAO and increased their expression of the anti-inflammatory M2 marker, CD206, by cell-cell interactions. Moreover, MG from female vs. male mice had higher expression of IL-4 and IL-10 receptors and increased production of IL-4, especially after treatment with IL-10(+) B-cells. These findings indicate that IL-10-producing B-cells play a crucial role in regulating MG activation, proinflammatory cytokine release and M2 phenotype induction, post-MCAO, with heightened sensitivity of female MG to IL-4 and IL-10. This study, coupled with our previous demonstration of increased numbers of transferred IL-10(+) B-cells in the ischemic hemisphere, provide a mechanistic basis for local regulation by secreted IL-10 and IL-4 as well as direct B-cell/MG interactions that promote M2-MG.
authors.affiliation: Neuroimmunology Research, R&D-31, VA Portland Health Care System, 3710 SW U.S. Veterans Hospital Rd., Portland, OR, 97239, USA.|Department of Neurology, Oregon Health & Science University, 3181 SW Sam Jackson Park Rd., Portland, OR, USA.
authors.forename: Sheetal
authors.initials: S
authors.lastname: Bodhankar
authors.affiliation: Neuroimmunology Research, R&D-31, VA Portland Health Care System, 3710 SW U.S. Veterans Hospital Rd., Portland, OR, 97239, USA.|Department of Neurology, Oregon Health & Science University, 3181 SW Sam Jackson Park Rd., Portland, OR, USA.
authors.forename: Andrew
authors.initials: A
authors.lastname: Lapato
authors.affiliation: Department of Anesthesiology & Perioperative Medicine, Oregon Health & Science University, 3181 SW Sam Jackson Park Rd., Portland, OR, USA.
authors.forename: Yingxin
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Neuroimmunology Research, R&D-31, VA Portland Health Care System, 3710 SW U.S. Veterans Hospital Rd., Portland, OR, 97239, USA.|Department of Neurology, Oregon Health & Science University, 3181 SW Sam Jackson Park Rd., Portland, OR, USA.|Department of Molecular Microbiology & Immunology, Oregon Health & Science University, 3181 SW Sam Jackson Park Rd., Portland, OR, USA.
authors.forename: Arthur A
authors.initials: AA
authors.lastname: Vandenbark
authors.affiliation: Department of Neurology, Oregon Health & Science University, 3181 SW Sam Jackson Park Rd., Portland, OR, USA.|Department of Anesthesiology & Perioperative Medicine, Oregon Health & Science University, 3181 SW Sam Jackson Park Rd., Portland, OR, USA.|Department of Medical and Molecular Genetics, Oregon Health & Science University, 3181 SW Sam Jackson Park Rd., Portland, OR, USA.
authors.forename: Julie A
authors.initials: JA
authors.lastname: Saugstad
authors.affiliation: Neuroimmunology Research, R&D-31, VA Portland Health Care System, 3710 SW U.S. Veterans Hospital Rd., Portland, OR, 97239, USA. offnerva@ohsu.edu.|Department of Neurology, Oregon Health & Science University, 3181 SW Sam Jackson Park Rd., Portland, OR, USA. offnerva@ohsu.edu.|Department of Anesthesiology & Perioperative Medicine, Oregon Health & Science University, 3181 SW Sam Jackson Park Rd., Portland, OR, USA. offnerva@ohsu.edu.
authors.forename: Halina
authors.initials: H
authors.lastname: Offner
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology; D002545:Brain Ischemia / Q000276:immunology* / Q000378:metabolism*; D002450:Cell Communication; D018920:Coculture Techniques; D005260:Female; D020244:Infarction, Middle Cerebral Artery / Q000378:metabolism / Q000473:pathology; D016753:Interleukin-10 / Q000235:genetics / Q000378:metabolism; D015847:Interleukin-4 / Q000378:metabolism; D037181:Lectins, C-Type / Q000096:biosynthesis / Q000235:genetics; D008297:Male; D000090323:Mannose Receptor; D037241:Mannose-Binding Lectins / Q000096:biosynthesis / Q000235:genetics; D051379:Mice; D008810:Mice, Inbred C57BL; D017628:Microglia / Q000276:immunology* / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000096:biosynthesis / Q000235:genetics; D012727:Sex Characteristics; D020521:Stroke / Q000276:immunology* / Q000378:metabolism*
chemical_list: C556062:IL10 protein, mouse; D037181:Lectins, C-Type; D000090323:Mannose Receptor; D037241:Mannose-Binding Lectins; D011956:Receptors, Cell Surface; D016753:Interleukin-10; D015847:Interleukin-4
keywords: IL-10-secreting B-cells; M1 and M2 MG states; MCAO; Microglia