title: Myelin-mediated inhibition of oligodendrocyte precursor differentiation can be overcome by pharmacological modulation of Fyn-RhoA and protein kinase C signalling.
abstract: Failure of oligodendrocyte precursor cell (OPC) differentiation contributes significantly to failed myelin sheath regeneration (remyelination) in chronic demyelinating diseases. Although the reasons for this failure are not completely understood, several lines of evidence point to factors present following demyelination that specifically inhibit differentiation of cells capable of generating remyelinating oligodendrocytes. We have previously demonstrated that myelin debris generated by demyelination inhibits remyelination by inhibiting OPC differentiation and that the inhibitory effects are associated with myelin proteins. In the present study, we narrow down the spectrum of potential protein candidates by proteomic analysis of inhibitory protein fractions prepared by CM and HighQ column chromatography followed by BN/SDS/SDS-PAGE gel separation using Nano-HPLC-ESI-Q-TOF mass spectrometry. We show that the inhibitory effects on OPC differentiation mediated by myelin are regulated by Fyn-RhoA-ROCK signalling as well as by modulation of protein kinase C (PKC) signalling. We demonstrate that pharmacological or siRNA-mediated inhibition of RhoA-ROCK-II and/or PKC signalling can induce OPC differentiation in the presence of myelin. Our results, which provide a mechanistic link between myelin, a mediator of OPC differentiation inhibition associated with demyelinating pathologies and specific signalling pathways amenable to pharmacological manipulation, are therefore of significant potential value for future strategies aimed at enhancing CNS remyelination.
authors.affiliation: Department of Neurosurgery, Medical University Vienna, Vienna, Austria.
authors.forename: Alexandra S
authors.initials: AS
authors.lastname: Baer
authors.forename: Yasir A
authors.initials: YA
authors.lastname: Syed
authors.forename: Sung Ung
authors.initials: SU
authors.lastname: Kang
authors.forename: Dieter
authors.initials: D
authors.lastname: Mitteregger
authors.forename: Raluca
authors.initials: R
authors.lastname: Vig
authors.forename: Charles
authors.initials: C
authors.lastname: Ffrench-Constant
authors.forename: Robin J M
authors.initials: RJ
authors.lastname: Franklin
authors.forename: Friedrich
authors.initials: F
authors.lastname: Altmann
authors.forename: Gert
authors.initials: G
authors.lastname: Lubec
authors.forename: Mark R
authors.initials: MR
authors.lastname: Kotter
mesh_terms: D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D000831:Animals, Newborn; D002227:Carbazoles / Q000494:pharmacology; D002454:Cell Differentiation; D003711:Demyelinating Diseases / Q000378:metabolism / Q000473:pathology*; D004591:Electrophoresis, Polyacrylamide Gel; D007211:Indoles / Q000494:pharmacology; D008301:Maleimides / Q000494:pharmacology; D009186:Myelin Sheath / Q000378:metabolism*; D009416:Nerve Regeneration; D009836:Oligodendroglia / Q000378:metabolism / Q000473:pathology*; D051571:Protein Kinase C-alpha / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D051076:Proto-Oncogene Proteins c-fyn / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000187:drug effects; D013234:Stem Cells / Q000378:metabolism / Q000473:pathology*; D054460:rho-Associated Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D020742:rhoA GTP-Binding Protein / Q000235:genetics / Q000378:metabolism*
chemical_list: D002227:Carbazoles; D007211:Indoles; D008301:Maleimides; D034741:RNA, Small Interfering; C467001:bisindolylmaleimide IX; C081021:Go 6976; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; C494961:Fyn protein, rat; D051076:Proto-Oncogene Proteins c-fyn; D054460:rho-Associated Kinases; D051571:Protein Kinase C-alpha; D020742:rhoA GTP-Binding Protein; C049347:fasudil