Dynamic expression of miR-206-3p during mouse skin development is independent of keratinocyte differentiation

MicroRNA-206 (miR-206), the homolog of which in mice is termed miR-206-3p, is a muscle-specific miRNA known to be important in the development of skeletal muscle, and is involved in smooth muscle innervation of the airway through the post‑transcriptional suppression of brain‑derived neurotrophic factor (Bdnf). miR‑206‑3p is also expressed at significant levels in adult and embryonic skin; however, its functional roles in adult skin and during skin development remain to be fully elucidated. In the present study, the spatiotemporal expression of miR‑206‑3p and its target‑gene, Bdnf, during mouse skin development were investigated. The expression level of miR‑206‑3p increased from 13.5 days postcoitus (dpc), peaked at 17.5 dpc and declined following birth. The observed temporal profile of the expression of miR‑206‑3p was accompanied by an inverse change in the protein expression levels of BDNF. However, the mRNA expression levels of Bdnf did not parallel those of BDNF protein. The localization of the expression of miR‑206‑3p was similar, or located near that of ubiquitin carboxyl‑terminal hydrolase L1 during skin development. An in vitro keratinocyte model demonstrated no significant differences between primary and differentiated keratinocytes in the expression levels of either miR‑206‑3p (P=0.227) or Bdnf (mRNA, P=0.118; mature BDNF, P=0.106; pro‑BDNF, P=0.905). These findings indicate a potential role for miR‑206‑3p in cutaneous innervation, which largely relies on BDNF neurotrophic support and is independent of keratinocyte differentiation. The results of the present study suggested that this novel mechanism may be targeted for developing potential therapeutic approaches.