title: Phosphorylation of αB-crystallin supports reactive astrogliosis in demyelination.
abstract: The small heat shock protein αB-crystallin (CRYAB) has been implicated in multiple sclerosis (MS) pathogenesis. Earlier studies have indicated that CRYAB inhibits inflammation and attenuates clinical disease when administered in the experimental autoimmune encephalomyelitis model of MS. In this study, we evaluated the role of CRYAB in primary demyelinating events. Using the cuprizone model of demyelination, a noninflammatory model that allows the analysis of glial responses in MS, we show that endogenous CRYAB expression is associated with increased severity of demyelination. Moreover, we demonstrate a strong correlation between the expression of CRYAB and the extent of reactive astrogliosis in demyelinating areas and in in vitro assays. In addition, we reveal that CRYAB is differentially phosphorylated in astrocytes in active demyelinating MS lesions, as well as in cuprizone-induced lesions, and that this phosphorylation is required for the reactive astrocyte response associated with demyelination. Furthermore, taking a proteomics approach to identify proteins that are bound by the phosphorylated forms of CRYAB in primary cultured astrocytes, we show that there is clear differential binding of protein targets due to the specific phosphorylation of CRYAB. Subsequent Ingenuity Pathway Analysis of these targets reveals implications for intracellular pathways and biological processes that could be affected by these modifications. Together, these findings demonstrate that astrocytes play a pivotal role in demyelination, making them a potential target for therapeutic intervention, and that phosphorylation of CRYAB is a key factor supporting the pathogenic response of astrocytes to oligodendrocyte injury.
authors.affiliation: Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305; hkuipers@stanford.edu steinman@stanford.edu.
authors.forename: Hedwich F
authors.identifier: 0000-0002-7275-5889
authors.initials: HF
authors.lastname: Kuipers
authors.affiliation: Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305.
authors.forename: Jane
authors.initials: J
authors.lastname: Yoon
authors.affiliation: Department of Molecular Cell Biology and Immunology, VU University Medical Center, Neuroscience Campus Amsterdam, 1081 HZ Amsterdam, The Netherlands.
authors.forename: Jack
authors.initials: J
authors.lastname: van Horssen
authors.affiliation: Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305.
authors.forename: May H
authors.initials: MH
authors.lastname: Han
authors.affiliation: Division of Infectious Diseases, Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305.
authors.forename: Paul L
authors.initials: PL
authors.lastname: Bollyky
authors.affiliation: Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA 94305.
authors.forename: Theo D
authors.initials: TD
authors.lastname: Palmer
authors.affiliation: Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305; hkuipers@stanford.edu steinman@stanford.edu.
authors.forename: Lawrence
authors.initials: L
authors.lastname: Steinman
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism*; D003471:Cuprizone / Q000494:pharmacology; D003711:Demyelinating Diseases / Q000378:metabolism*; D004195:Disease Models, Animal; D004681:Encephalomyelitis, Autoimmune, Experimental / Q000139:chemically induced / Q000378:metabolism; D005260:Female; D006801:Humans; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009103:Multiple Sclerosis / Q000139:chemically induced / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009836:Oligodendroglia / Q000187:drug effects / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects / Q000502:physiology*; D038203:alpha-Crystallin B Chain / Q000378:metabolism*
chemical_list: D009419:Nerve Tissue Proteins; D038203:alpha-Crystallin B Chain; D003471:Cuprizone
keywords: astrogliosis; cuprizone; demyelination; phosphorylation; proteomics