Methylthioadenosine promotes remyelination by inducing oligodendrocyte differentiation

Abstract

Methylthioadenosine is a metabolite of the polyamine pathway that modulates methyltransferase activity, thereby influencing DNA and protein methylation. Since methylthioadenosine produces neuroprotection in models of inflammation, ischemia and epilepsy, we set out to evaluate the role of methylthioadenosine in promoting remyelination, a process that will protect axons in demyelinating diseases and that will aid functional recovery. The effect of methylthioadenosine in promoting remyelination was tested in mouse cerebellum organotypic cultures that were exposed to lipopolysaccharide to induce neuroinflammation, or lysolecithin to induce chemical demyelination. In addition methylthioadenosine administration was also tested in vivo, using the cuprizone model of demyelination. The molecular pathways involved in this methylthioadenosine activity were evaluated in primary cortical mouse astrocytes. In models of neuroinflammation or chemical demyelination, methylthioadenosine prevented the loss of myelin and promoted remyelination in vitro by increasing the number of mature myelinating oligodendrocytes. Methylthioadenosine enhanced myelin production in the cuprizone model, in conjunction with a clinical improvement. Methylthioadenosine enhanced STAT-3 phosphorylation in astrocytes in vitro, and the production of ciliary neurotrophic factor (CNTF), a trophic factor known to promote oligodendrocyte maturation and differentiation, as well as remyelination. The remyelination promoted by methylthioadenosine suggests a role for the polyamine pathway in oligodendrocyte maturation and survival, paving the way for new therapeutic strategies to promote regeneration in Multiple Sclerosis and other demyelinating diseases.