Immune cell modulation of oligodendrocyte lineage cells.

Chronic demyelination and the concomitant loss of trophic support and increased energy demands in axons are thought to contribute to neurodegeneration in a number of neurological diseases such as multiple sclerosis (MS). Adult oligodendrocyte precursor cells (OPCs) play an important role in these demyelinating diseases by generating new myelinating oligodendrocytes that may help limit axonal degeneration. Thus, promoting the differentiation of OPCs and functional integration of newly generated oligodendrocytes is a crucial avenue for the next generation of therapies. Evidence to date suggests that the immune system may both positively and negatively impact OPC differentiation and endogenous remyelination in disease. Inflammatory cytokines not only suppress OPC differentiation but may also directly affect other functions of OPCs. Recent studies have demonstrated that OPCs and oligodendrocytes in both human multiple sclerosis lesions and mouse models of demyelination can express an immunogenic transcriptional signature and upregulate antigen presenting genes. In inflammatory demyelinating mouse models OPCs are capable of presenting antigen and activating CD8 + T cells. Here we review the evidence for this new role of oligodendroglia as antigen presenting cells and how these inflammatory OPCs (iOPCs) and inflammatory oligodendrocytes (iOLs) may influence myelin repair and other disease processes.