MicroRNA-30b regulates the polarity of retinal ganglion cells by inhibiting semaphorin-3A.

PURPOSE: Retinal ganglion cell (RGC) polarity plays an important role in optic nerve regeneration. This study was designed to investigate whether semaphorin-3A (Sema3A) is involved in the regulation of RGC polarity and Sema3A protein expression.

METHODS

Cultured primary RGCs were treated with Fc-Sema3A or Sema3A siRNA or transfected with purified miR-30b recombinant adenoassociated virus (rAAV). The polarity of the RGCs was observed with immunofluorescence. A western blot analysis of phosphorylated protein kinase A (p-PKA), the downstream effector molecule phosphorylated glycogen synthase kinase 3 beta (GSK-3β), and collapsing response mediator protein 2 (CRMP2) was performed.

RESULTS

We found that Sema3A could statistically significantly promote dendritic branching while inhibiting the growth of axons in RGCs. miR-30b overexpression and Sema3A siRNA could statistically significantly promote the growth of axons while inhibiting the growth of dendrites from RGCs. Additionally, miR-30b could restrain the expression of Sema3A protein and its downstream PKA/GSK-3β/CRMP2 signaling pathways.

CONCLUSIONS

The results indicate that Sema3A promotes dendritic growth and inhibits axonal growth, which is not conducive to the early repair of optic nerve injury. The overexpression of miR-30b can overcome this problem, and may represent a new target for the treatment of nerve injury and regeneration in the future.