title: Th1 cells downregulate connexin 43 gap junctions in astrocytes via microglial activation.
abstract: We previously reported early and extensive loss of astrocytic connexin 43 (Cx43) in acute demyelinating lesions of multiple sclerosis (MS) patients. Because it is widely accepted that autoimmune T cells initiate MS lesions, we hypothesized that infiltrating T cells affect Cx43 expression in astrocytes, which contributes to MS lesion formation. Primary mixed glial cell cultures were prepared from newborn mouse brains, and microglia were isolated by anti-CD11b antibody-conjugated magnetic beads. Next, we prepared astrocyte-rich cultures and astrocyte/microglia-mixed cultures. Treatment of primary mixed glial cell cultures with interferon (IFN) γ, interleukin (IL)-4, or IL-17 showed that only IFNγ or IL-17 at high concentrations reduced Cx43 protein levels. Upon treatment of astrocyte-rich cultures and astrocyte/microglia-mixed cultures with IFNγ, Cx43 mRNA/protein levels and the function of gap junctions were reduced only in astrocyte/microglia-mixed cultures. IFNγ-treated microglia-conditioned media and IL-1β, which was markedly increased in IFNγ-treated microglia-conditioned media, reduced Cx43 protein levels in astrocyte-rich cultures. Finally, we confirmed that Th1 cell-conditioned medium decreased Cx43 protein levels in mixed glial cell cultures. These findings suggest that Th1 cell-derived IFNγ activates microglia to release IL-1β that reduces Cx43 gap junctions in astrocytes. Thus, Th1-dominant inflammatory states disrupt astrocytic intercellular communication and may exacerbate MS.
authors.affiliation: Department of Neurology, Neurological Institute, Graduate School of Medical Sciences, Kyushu University, Fukuoka, 812-8582, Japan.
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Watanabe
authors.affiliation: Department of Neurology, Neurological Institute, Graduate School of Medical Sciences, Kyushu University, Fukuoka, 812-8582, Japan.
authors.forename: Katsuhisa
authors.initials: K
authors.lastname: Masaki
authors.affiliation: Department of Neurology, Neurological Institute, Graduate School of Medical Sciences, Kyushu University, Fukuoka, 812-8582, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Yamasaki
authors.affiliation: Department of Neuroimmunology, Research Institute of Environmental Medicine, Nagoya University, Nagoya, 464-8601, Japan.|Institute of Traditional Chinese Medicine, Suzuka University of Medical Science, Suzuka, 510-0226, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Kawanokuchi
authors.affiliation: Department of Neuroimmunology, Research Institute of Environmental Medicine, Nagoya University, Nagoya, 464-8601, Japan.|Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, Yokohama, 236-0004, Japan.
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Takeuchi
authors.affiliation: Department of Neurology, Neurological Institute, Graduate School of Medical Sciences, Kyushu University, Fukuoka, 812-8582, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Matsushita
authors.affiliation: Department of Neuroimmunology, Research Institute of Environmental Medicine, Nagoya University, Nagoya, 464-8601, Japan.
authors.forename: Akio
authors.initials: A
authors.lastname: Suzumura
authors.affiliation: Department of Neurology, Neurological Institute, Graduate School of Medical Sciences, Kyushu University, Fukuoka, 812-8582, Japan.
authors.forename: Jun-Ichi
authors.initials: JI
authors.lastname: Kira
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000378:metabolism / Q000473:pathology; D002450:Cell Communication / Q000235:genetics / Q000276:immunology; D018031:Connexin 43 / Q000235:genetics*; D004195:Disease Models, Animal; D017629:Gap Junctions / Q000235:genetics / Q000473:pathology; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D007371:Interferon-gamma / Q000235:genetics* / Q000378:metabolism; D020381:Interleukin-17 / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D053583:Interleukin-1beta / Q000235:genetics* / Q000378:metabolism; D015847:Interleukin-4 / Q000276:immunology / Q000378:metabolism; D008262:Macrophage Activation / Q000235:genetics / Q000276:immunology; D051379:Mice; D017628:Microglia / Q000378:metabolism; D009103:Multiple Sclerosis / Q000235:genetics* / Q000276:immunology / Q000503:physiopathology; D009457:Neuroglia / Q000378:metabolism / Q000473:pathology; D018417:Th1 Cells / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism
chemical_list: D018031:Connexin 43; C000611649:IFNG protein, mouse; D020381:Interleukin-17; D053583:Interleukin-1beta; D015847:Interleukin-4; D007371:Interferon-gamma