title: Limiting multiple sclerosis related axonopathy by blocking Nogo receptor and CRMP-2 phosphorylation.
abstract: Multiple sclerosis involves demyelination and axonal degeneration of the central nervous system. The molecular mechanisms of axonal degeneration are relatively unexplored in both multiple sclerosis and its mouse model, experimental autoimmune encephalomyelitis. We previously reported that targeting the axonal growth inhibitor, Nogo-A, may protect against neurodegeneration in experimental autoimmune encephalomyelitis; however, the mechanism by which this occurs is unclear. We now show that the collapsin response mediator protein 2 (CRMP-2), an important tubulin-associated protein that regulates axonal growth, is phosphorylated and hence inhibited during the progression of experimental autoimmune encephalomyelitis in degenerating axons. The phosphorylated form of CRMP-2 (pThr555CRMP-2) is localized to spinal cord neurons and axons in chronic-active multiple sclerosis lesions. Specifically, pThr555CRMP-2 is implicated to be Nogo-66 receptor 1 (NgR1)-dependent, since myelin oligodendrocyte glycoprotein (MOG)(35-55)-induced NgR1 knock-out (ngr1(-)(/)(-)) mice display a reduced experimental autoimmune encephalomyelitis disease progression, without a deregulation of ngr1(-)(/)(-) MOG(35-55)-reactive lymphocytes and monocytes. The limitation of axonal degeneration/loss in experimental autoimmune encephalomyelitis-induced ngr1(-)(/)(-) mice is associated with lower levels of pThr555CRMP-2 in the spinal cord and optic nerve during experimental autoimmune encephalomyelitis. Furthermore, transduction of retinal ganglion cells with an adeno-associated viral vector encoding a site-specific mutant T555ACRMP-2 construct, limits optic nerve axonal degeneration occurring at peak stage of experimental autoimmune encephalomyelitis. Therapeutic administration of the anti-Nogo(623-640) antibody during the course of experimental autoimmune encephalomyelitis, associated with an improved clinical outcome, is demonstrated to abrogate the protein levels of pThr555CRMP-2 in the spinal cord and improve pathological outcome. We conclude that phosphorylation of CRMP-2 may be downstream of NgR1 activation and play a role in axonal degeneration in experimental autoimmune encephalomyelitis and multiple sclerosis. Blockade of Nogo-A/NgR1 interaction may serve as a viable therapeutic target in multiple sclerosis.
authors.affiliation: Monash Immunology and Stem Cell Laboratories, Monash University, Clayton VIC 3800, Australia. steven.petratos@monash.edu
authors.forename: Steven
authors.initials: S
authors.lastname: Petratos
authors.forename: Ezgi
authors.initials: E
authors.lastname: Ozturk
authors.forename: Michael F
authors.initials: MF
authors.lastname: Azari
authors.forename: Rachel
authors.initials: R
authors.lastname: Kenny
authors.forename: Jae Young
authors.initials: JY
authors.lastname: Lee
authors.forename: Kylie A
authors.initials: KA
authors.lastname: Magee
authors.forename: Alan R
authors.initials: AR
authors.lastname: Harvey
authors.forename: Courtney
authors.initials: C
authors.lastname: McDonald
authors.forename: Kasra
authors.initials: K
authors.lastname: Taghian
authors.forename: Leon
authors.initials: L
authors.lastname: Moussa
authors.forename: Pei
authors.initials: P
authors.lastname: Mun Aui
authors.forename: Christopher
authors.initials: C
authors.lastname: Siatskas
authors.forename: Sara
authors.initials: S
authors.lastname: Litwak
authors.forename: Michael G
authors.initials: MG
authors.lastname: Fehlings
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Strittmatter
authors.forename: Claude C A
authors.initials: CC
authors.lastname: Bernard
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D000818:Animals; D000906:Antibodies / Q000627:therapeutic use; D001369:Axons / Q000378:metabolism* / Q000473:pathology / Q000648:ultrastructure; D017252:CD3 Complex / Q000378:metabolism; D045744:Cell Line, Tumor; D003711:Demyelinating Diseases / Q000209:etiology / Q000378:metabolism / Q000473:pathology; D004195:Disease Models, Animal; D004681:Encephalomyelitis, Autoimmune, Experimental / Q000150:complications* / Q000188:drug therapy / Q000276:immunology; D005260:Female; D058851:GPI-Linked Proteins / Q000037:antagonists & inhibitors / Q000172:deficiency / Q000276:immunology; D005786:Gene Expression Regulation / Q000235:genetics; D006023:Glycoproteins / Q000009:adverse effects; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D047468:Immunoprecipitation; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000150:complications / Q000473:pathology*; D009154:Mutation / Q000235:genetics; D009185:Myelin Proteins / Q000037:antagonists & inhibitors / Q000172:deficiency / Q000276:immunology; D063308:Myelin-Oligodendrocyte Glycoprotein; D009410:Nerve Degeneration / Q000209:etiology / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D009447:Neuroblastoma / Q000473:pathology; D016900:Neurofilament Proteins / Q000378:metabolism; D000070816:Nogo Receptor 1; D009900:Optic Nerve / Q000378:metabolism / Q000473:pathology; D010446:Peptide Fragments / Q000009:adverse effects; D010766:Phosphorylation; D011956:Receptors, Cell Surface / Q000037:antagonists & inhibitors / Q000172:deficiency / Q000276:immunology; D012165:Retinal Ganglion Cells / Q000378:metabolism / Q000473:pathology; D012720:Severity of Illness Index; D016622:Silver Staining; D013116:Spinal Cord / Q000378:metabolism / Q000473:pathology; D013997:Time Factors; D014161:Transduction, Genetic; D014404:Tubulin / Q000378:metabolism; D016875:tau Proteins / Q000378:metabolism
chemical_list: D000906:Antibodies; D017252:CD3 Complex; D058851:GPI-Linked Proteins; D006023:Glycoproteins; D036341:Intercellular Signaling Peptides and Proteins; D009185:Myelin Proteins; D063308:Myelin-Oligodendrocyte Glycoprotein; D009419:Nerve Tissue Proteins; D016900:Neurofilament Proteins; D000070816:Nogo Receptor 1; D010446:Peptide Fragments; D011956:Receptors, Cell Surface; C419790:Rtn4r protein, mouse; C498585:TUBB3 protein, human; D014404:Tubulin; C095114:collapsin response mediator protein-2; C445081:myelin oligodendrocyte glycoprotein (35-55); D016875:tau Proteins; C051774:neurofilament protein H; D049452:Green Fluorescent Proteins