Dataset Information

M2 microglia and macrophages drive oligodendrocyte differentiation during CNS remyelination.

ABSTRACT: The lack of therapies for progressive multiple sclerosis highlights the need to understand the regenerative process of remyelination that can follow CNS demyelination. This involves an innate immune response consisting of microglia and macrophages, which can be polarized to distinct functional phenotypes: pro-inflammatory (M1) and anti-inflammatory or immunoregulatory (M2). We found that a switch from an M1- to an M2-dominant response occurred in microglia and peripherally derived macrophages as remyelination started. Oligodendrocyte differentiation was enhanced in vitro with M2 cell conditioned media and impaired in vivo following intra-lesional M2 cell depletion. M2 cell densities were increased in lesions of aged mice in which remyelination was enhanced by parabiotic coupling to a younger mouse and in multiple sclerosis lesions that normally show remyelination. Blocking M2 cell-derived activin-A inhibited oligodendrocyte differentiation during remyelination in cerebellar slice cultures. Thus, our results indicate that M2 cell polarization is essential for efficient remyelination and identify activin-A as a therapeutic target for CNS regeneration.

SUBMITTER: Miron VE

PROVIDER: S-EPMC3977045 | biostudies-literature | 2013 Sep

REPOSITORIES: biostudies-literature

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M2 microglia and macrophages drive oligodendrocyte differentiation during CNS remyelination.

Miron Veronique E VE Boyd Amanda A Zhao Jing-Wei JW Yuen Tracy J TJ Ruckh Julia M JM Shadrach Jennifer L JL van Wijngaarden Peter P Wagers Amy J AJ Williams Anna A Franklin Robin J M RJM Ffrench-Constant Charles C

Nature neuroscience 20130721 9

The lack of therapies for progressive multiple sclerosis highlights the need to understand the regenerative process of remyelination that can follow CNS demyelination. This involves an innate immune response consisting of microglia and macrophages, which can be polarized to distinct functional phenotypes: pro-inflammatory (M1) and anti-inflammatory or immunoregulatory (M2). We found that a switch from an M1- to an M2-dominant response occurred in microglia and peripherally derived macrophages as ...[more]

PMID: 23872599

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Project description:HMGB1 is a highly conserved, ubiquitous protein in eukaryotic cells. HMGB1 is normally localized to the nucleus, where it acts as a chromatin associated non-histone binding protein. In contrast, extracellular HMGB1 is an alarmin released by stressed cells to act as a danger associated molecular pattern (DAMP). We have recently determined that progenitor cells from multiple sclerosis patients exhibit a cellular senescent phenotype and release extracellular HMGB1 which directly impaired the maturation of oligodendrocyte progenitor cells (OPCs) to myelinating oligodendrocytes (OLs). Herein, we report that administration of recombinant HMGB1 into the spinal cord at the time of lysolecithin administration resulted in arrest of OPC differentiation in vivo, and a profound impairment of remyelination. To define the receptor by which extracellular HMGB1 mediates its inhibitory influence on OPCs to impair OL differentiation, we tested selective inhibitors against the four primary receptors known to mediate the effects of HMGB1, the toll-like receptors (TLRs)-2, -4, -9 or the receptor for advanced glycation end-products (RAGE). We found that inhibition of neither TLR9 nor RAGE increased OL differentiation in the presence of HMGB1, while inhibition of TLR4 resulted in partial restoration of OL differentiation and inhibiting TLR2 fully restored differentiation of OLs in the presence of HMGB1. Analysis of transcriptomic data (RNAseq) from OPCs identified an overrepresentation of NFκB regulated genes in OPCs when in the presence of HMGB1. We found that application of HMGB1 to OPCs in culture resulted in a rapid and concentration dependent shift in NFκB nuclear translocation which was also attenuated with coincident TLR2 inhibition. These data provide new information on how extracellular HMGB1 directly affects the differentiation potential of OPCs. Recent and past evidence for elevated HMGB1 released from senescent progenitor cells within demyelinated lesions in the MS brain suggests that a greater understanding of how this molecule acts on OPCs may unfetter the endogenous remyelination potential in MS.

Project description:We used transcription-profiling to identify mitogen-activated protein kinase (Mapk) signaling as an important regulator involved in the differentiation of oligodendrocyte progenitor cells (OPCs) into oligodendrocytes. We show in tissue culture that activation of Mapk signaling by elevation of intracellular levels of cAMP using administration of either dibutyryl-cAMP or inhibitors of the cAMP-hydrolyzing enzyme phosphodiesterase-4 (Pde4) enhances OPC differentiation. Finally, we demonstrate that systemic delivery of a Pde4 inhibitor leads to enhanced differentiation of OPCs within focal areas of toxin-induced demyelination and a consequent acceleration of remyelination. Study was conducted to identify the genes that are differentialy regulated during early time point of OPC differentiation. This study includes reanalyzed data from the following 6 Samples available in GSE24821: [i] 5 days post lesion (dpl) laser captured caudal cerebellar peduncle (CCP) replicates 1-3 (GSM610956-GSM610958), and [ii] 14 dpl laser captured CCP replicates 1-3 (GSM610959-GSM610961). For the reanalyzed data, raw data files were background-corrected, normalized and summarized using the RMA algorithm as implemented in the R statistical programming environment (http://www.r-project.org). Differential expression between sample groups was assessed using the moderated t-test as implemented in the limma package for the Bioconductor suite of R bioinformatics software (http://bioconductor.org). In order to correct for hypothesis testing on such a scale, P-values relating to differential expression were corrected for multiple testing using FDR correction. Differential expression across sample groups was deemed significant at an FDR of 5% (q < 0.05). The processed data for the reanalyzed dataset is linked below as supplementary file 'GSE50042_reanalyzed_Samples.txt'. The processed data for Samples GSM1213100-GSM1213114 is linked below as supplementary file 'GSE50042_processed_data.txt'.

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Dataset Information

M2 microglia and macrophages drive oligodendrocyte differentiation during CNS remyelination.

Publications

M2 microglia and macrophages drive oligodendrocyte differentiation during CNS remyelination.

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