Oligodendroglia as functional effectors of Multiple Sclerosis risk variants

Multiple sclerosis (MS) is a neuroinflammatory disease for which a large number of non-coding single nucleotide polymorphisms (SNPs) have been associated with disease risk/susceptibility. Immune cells have been suggested as the principal functional effector cell types of these common variants. Here, we identify 76 MS-associated SNPs whose loci present accessible chromatin in homeostatic and diseased oligodendroglia (OLG), including both oligodendrocyte precursor cells (OPCs) and mature oligodendrocytes (MOLs). By applying high-throughput functional genomics, we found that a subset of these SNPs led to variant- and cell-specific regulatory effects in human induced pluripotent stem cell-derived oligodendroglia. Phenotypic profiling of these variants indicated that rs483180:PHGDH interfered with human OPC proliferation via long-range chromatin interactions with the S100A6 locus, while variants at rs2248137:CYP24A1 impaired oligodendrocyte differentiation by regulating BCAS1 expression. In addition, variants at rs1415069:DIPK1A enhanced secretion of the cytokine CCL2 by oligodendroglia, suggesting that these variants might be implicated in OLG-driven immune cell recruitment in MS. These findings position oligodendroglia as important drivers of MS pathogenesis through modulation of both their cell-intrinsic oligodendroglial function and intercellular communication by non-coding MS risk variants.