Muscarinic Receptor M3R Signaling Prevents Efficient Remyelination by Human and Mouse Oligodendrocyte Progenitor Cells

Muscarinic receptor antagonists act as potent inducers of oligodendrocyte differentiation and accelerate remyelination. However, the use of muscarinic antagonists in the clinic is limited by poor understanding of the operant receptor subtype, and questions regarding possible species differences between rodents and humans. Based on high selective expression in human oligodendrocyte progenitor cells (OPCs), we hypothesized that M 3 R is the functionally relevant receptor. Lentiviral M 3 R knock-down in human primary CD140a/PDGFαR + OPCs resulted in enhanced differentiation in vitro and substantially reduced the calcium response following muscarinic agonist treatment. Importantly, following transplantation in hypomyelinating shiverer/rag2 mice, M 3 R knock-down improved remyelination by human OPCs. Furthermore, conditional M 3 R ablation in adult NG2-expressing OPCs increased oligodendrocyte differentiation and led to improved spontaneous remyelination in mice. Together, we demonstrate that M 3 R receptor mediates muscarinic signaling in human OPCs that act to delay differentiation and remyelination, suggesting that M 3 receptors are viable targets for human demyelinating disease. SIGNIFICANCE STATEMENT The identification of drug targets aimed at improving remyelination in patients with demyelination disease is a key step in development of effective regenerative therapies to treat diseases such as multiple sclerosis. Muscarinic receptor antagonists have been identified as effective potentiators of remyelination but the receptor subtypes that mediate these receptors are unclear. In this study, Welliver et al. show that genetic M 3 R ablation in both mouse and human cells results in improved remyelination and is mediated by acceleration of oligodendrocyte commitment from oligodendrocyte progenitor cells. Therefore, M 3 R therefore represents an attractive target for induced remyelination in human disease.