The Role of miR-214-3p in Hair Follicle Neural Crest Stem Cell-derived Exosomes in the Repair of Peripheral Nerve Injury

Harnessing the potential of stem cell-derived exosomes represents a promising cell-free therapeutic strategy for peripheral nerve regeneration. The purpose of this study is to investigate the role and mechanism of hair follicle neural crest stem cell-derived exosomes (hfNCSCs-Exos) in neurite outgrowth and regeneration of impaired neurons. Primary hfNCSCs were isolated and cultured, and the characteristics of hfNCSCs-Exos were identified via immunocytochemical staining and Western blot. Over-expression and down-regulation of miR-214-3p in hfNCSCs-Exos were established. An acrylamide-induced dorsal root ganglion (DRG) cell injury model in rats and a sciatic nerve defect model were constructed in vitro and in vivo, respectively. The effects of hfNCSCs-Exos and differential expression of miR-214-3p on neurite outgrowth and regeneration were assessed by immunocytochemical staining. hfNCSCs-Exos promoted axon extension in injured DRG neurons, and the fluorescence intensity of GAP43 and NF200 was higher than that in the injury group. This effect was particularly enhanced with overexpression of miR-214-3p, which yielded the most significant results in the above experiments. In vivo experiments showed that hfNCSCs-Exos significantly promoted nerve regeneration. In contrast, the down-regulated miR-214-3p hfNCSCs-Exos group showed results similar to the PBS control group, while hfNCSCs-Exos overexpressing miR-214-3p exhibited a strong positive effect on nerve regeneration. In terms of functional recovery, hfNCSCs-Exos, especially those overexpressing miR-214-3p, positively influenced the maintenance of muscle morphology and restoration of motor function. These results demonstrate that miR-214-3p derived from hfNCSCs plays an important role in promoting neurite outgrowth during nerve regeneration.