title: Extensive dysregulations of oligodendrocytic and astrocytic connexins are associated with disease progression in an amyotrophic lateral sclerosis mouse model.
abstract: BACKGROUND
  Non-cell-autonomous motor neuronal death is suggested in a mutant Cu/Zn superoxide dismutase 1 (mSOD1)-mediated amyotrophic lateral sclerosis (ALS) model, in which glial cells play significant roles in disease progression. Connexins (Cxs) form homotypic or heterotypic gap junctions (GJs) and allow direct intercellular communications among nervous tissue cells. The role of Cxs in motor neuron disease has never been investigated; therefore, we aimed to evaluate alterations of Cxs in mSOD1-transgenic (mSOD1-Tg) mice in comparison with their non-transgenic (non-Tg) littermates at the same ages.
  
  
  METHODS
  We pathologically evaluated temporal changes to astrocytic Cx43/Cx30 and oligodendrocytic Cx47/Cx32 immunoreactivities at presymptomatic, disease-progressive, and end stages, relative to aquaporin-4 (AQP4), glial fibrillary acidic protein (GFAP), excitatory amino acid transporter-2 (EAAT2), myelin-oligodendrocyte glycoprotein (MOG), and Nogo-A immunoreactivities, and observed neuronal loss by NeuN and neurofilament immunostaining, and microglial response by Iba-1 immunostaining. We also performed quantitative immunoblotting and real-time PCR analyses for Cxs.
  
  
  RESULTS
  The mSOD1-Tg mice showed neuronal and axonal loss in the anterior horns of the lumbar spinal cord accompanied by increased activation of microglia compared with non-Tg mice at the disease-progressive and end stages. Expression patterns of Cxs were not different between mSOD1-Tg and non-Tg mice at the presymptomatic stage, but immunoreactivities for GFAP, Cx43, Cx30 and AQP4 were increased in the anterior horns of mSOD1-Tg mice at the disease-progressive and end stages. By contrast, Cx47 and Cx32 immunoreactivities were markedly diminished in Nogo-A-positive oligodendrocytes in the anterior horns of mSOD1-Tg mice at the disease-progressive and end stages, especially in oligodendrocytes showing SOD1 accumulation. EAAT2 immunoreactivity was also diminished in the anterior horns of mSOD1-Tg mice at the disease-progressive and end stages. Quantitative immunoblotting revealed a significant reduction in Cx47 and Cx32 protein levels in mSOD1-Tg mice at the disease-progressive and end stages. The levels of Cx47 and Cx32 mRNAs were also decreased at these stages.
  
  
  CONCLUSIONS
  Our findings indicate that oligodendrocytic and astrocytic GJ proteins in the anterior horns of spinal cord in mSOD1-Tg mice are profoundly affected at the disease-progressive and end stages, where disruption of GJs among glial cells may exacerbate motor neuronal death.
authors.forename: Yiwen
authors.initials: Y
authors.lastname: Cui
authors.forename: Katsuhisa
authors.initials: K
authors.lastname: Masaki
authors.forename: Ryo
authors.initials: R
authors.lastname: Yamasaki
authors.forename: Shihoko
authors.initials: S
authors.lastname: Imamura
authors.forename: Satoshi O
authors.initials: SO
authors.lastname: Suzuki
authors.forename: Shintaro
authors.initials: S
authors.lastname: Hayashi
authors.forename: Shinya
authors.initials: S
authors.lastname: Sato
authors.forename: Yuko
authors.initials: Y
authors.lastname: Nagara
authors.forename: Mami F
authors.initials: MF
authors.lastname: Kawamura
authors.affiliation: Department of Neurology, Neurological Institute, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan. kira@neuro.med.kyushu-u.ac.jp.
authors.forename: Jun-ichi
authors.initials: J
authors.lastname: Kira
mesh_terms: D000690:Amyotrophic Lateral Sclerosis / Q000235:genetics / Q000473:pathology*; D000818:Animals; D051401:Aquaporin 4 / Q000378:metabolism; D001253:Astrocytes / Q000378:metabolism*; D017630:Connexins / Q000378:metabolism*; D004195:Disease Models, Animal; D018450:Disease Progression; D005786:Gene Expression Regulation / Q000235:genetics*; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D018613:Microscopy, Confocal; D009836:Oligodendroglia / Q000378:metabolism*; D012333:RNA, Messenger; D013116:Spinal Cord / Q000378:metabolism / Q000473:pathology; D013482:Superoxide Dismutase / Q000235:genetics
chemical_list: C496031:Aqp4 protein, mouse; D051401:Aquaporin 4; D017630:Connexins; D005904:Glial Fibrillary Acidic Protein; D012333:RNA, Messenger; C109415:SOD1 G93A protein; D013482:Superoxide Dismutase