Figure 8.

Decorin and RA signaling role in NG2⁺ cell differentiation into myelinating oligodendrocytes. Schematic representation of the proposed interplay between decorin- and RARα-mediated differentiation of NG2⁺ cells into myelinating oligodendrocytes. Activation of RARβ in neurons results in the upregulation of decorin, which is released and downregulates the EGFR in NG2⁺ cells. This leads to a decrease in intracellular calcium. The NG2⁺ cells that are synthesizing RA will cease/decrease RA secretion in exosomes due to the lowering of intracellular calcium and this will lead to an increase of intracellular RA to activate RARα signaling that drives differentiation into myelinating oligodendrocytes. Additionally, decorin decreases the CSPGs derived from reactive astrocytes and thus tackles a major obstacle to myelination.