The role of miR-9 during neuron differentiation of mouse retinal stem cells.

Retinal stem cells (RSCs) have been defined as neural cells with the potential to self-renew and to generate all the different cell types of the nervous system following differentiation, which are an ideal engraft in retinal regeneration. In this research, mouse RSCs were isolated from retina, induced differentiation into neuron cells in vitro after over-expression of miR-9. The results showed that the RSCs could induce differentiation into neuron cells under the special medium, but when the miR-9 was over-expressed, the differentiated efficiency of neuron cells from RSCs could be promoted. This reason was demonstrated that polypyrimidine tract-binding protein 1 (PTBP1) was a repressor for polypyrimidine tract-binding protein 2 (PTBP2), during neuronal differentiation, miR-9 reduced PTBP1 levels, leading to the accumulation of correctly spliced PTBP2 mRNA and a dramatic increase in PTBP2 protein. And then miR-9 promoted neuron cells from RSCs were successful colonized into injured spinal cord for participation in tissue-repair. In conclusion, our research showed that the miR-9 promoted the differentiation of neuronal cells from RSCs, and this mechanism was miR-9 reduced the expression of PTBP1, increased the expression of PTBP2.