Journal Article

Myelin-mediated inhibition of oligodendrocyte precursor differentiation can be overcome by pharmacological modulation of Fyn-RhoA and protein kinase C signalling

Alexandra S. Baer, Yasir A. Syed, Sung Ung Kang, Dieter Mitteregger, Raluca Vig, Charles ffrench-Constant, Robin J. M. Franklin, Friedrich Altmann, Gert Lubec and Mark R. Kotter

in Brain

Published on behalf of The Guarantors of Brain

Volume 132, issue 2, pages 465-481
Published in print February 2009 | ISSN: 0006-8950
Published online February 2009 | e-ISSN: 1460-2156 | DOI: http://dx.doi.org/10.1093/brain/awn334

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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.

Keywords: adult stem/precursor cells; oligodendrocyte; differentiation; myelin inhibitors; intracellular signalling; multiple sclerosis; remyelination

Journal Article.  10850 words.  Illustrated.

Subjects: Neurology ; Neuroscience

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