miR-410 controls adult SVZ neurogenesis by targeting neurogenic genes

Over-expression of the early neural inducer, Noggin, in nestin positive subventricular zone (SVZ), neural stem cells (NSC) promotes proliferation and neuronal differentiation of neural progenitors and inhibits the expression of a CNS-enriched microRNA-410 (miR-410) (Morell et al., 2015). When expressed in neurospheres derived from the adult SVZ, miR-410 inhibits neuronal and oligodendrocyte differentiation, and promotes astrocyte differentiation. miR-410 also reverses the increase in neuronal differentiation and decreased astroglial differentiation caused by Noggin over-expression. Conversely, inhibition of miR-410 activity promotes neuronal and decreases astroglial differentiation of NSC. Using computer prediction algorithms and luciferase reporter assays we identified multiple neurogenic genes including Elavl4 as downstream targets of miR-410 via the canonical miRNA-3'UTR interaction. Over-expression of Elavl4 transcripts without the endogenous 3'UTR rescued the decrease in neuronal differentiation caused by miR-410 overexpression. Interestingly, we also observed that miR-410 affected neurite morphology; over-expression of miR-410 resulted in the formation of short, unbranched neurites. We conclude that miR-410 expression provides a new link between BMP signaling and the crucial lineage choice of adult neural stem cells via its ability to bind and control the expression of neurogenic gene transcripts.