Chi-miR-370-3p regulates hair follicle development of Inner Mongolian cashmere goats
Abstract Background MicroRNAs (miRNAs), a class of 22 nucleotide (nt) non-coding RNAs, negatively regulate mRNA post-transcriptional modification in various biological processes. Initiation of skin hair follicles in cashmere goats is a dynamic process involving many key signalling molecules, but the associated cellular biological mechanisms induced by these key signalling molecules have not been reported. Results In this study, differential expression, bioinformatics, and Gene Ontology (GO)/Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed on miRNA expression profiles of Inner Mongolian cashmere goats at 45, 55, and 65 days during the foetal period, and chi-miR-370-3p was identified and investigated further. Real-time fluorescence quantification (qRT-PCR), dual luciferase reporting, and western blotting results showed that transforming growth factor beta receptor 2 (TGF-βR2) and fibroblast growth factor receptor 2 (FGFR2) were the target genes of chi-miR-370-3p. Chi-miR-370-3p also regulated the expression of TGF-βR2 and FGFR2 at mRNA and protein levels in epithelial cells and dermal fibroblasts. DNA staining, Cell Counting Kit-8 (CCK8), and fluorescein-labelled Annexin V results showed that chi-miR-370-3p inhibited the proliferation of epithelial cells and fibroblasts, but had no effect on apoptosis. Cell scratch test results showed that chi-miR-370-3p promoted the migration of epithelial cells and fibroblasts. Conclusion Chi-miR-370-3p inhibits the proliferation of epithelial cells and fibroblasts by targeting TGF-βR2 and FGFR2, thereby improving cell migration ability, and ultimately regulating the fate of epithelial cells and dermal fibroblasts to develop the placode (PC) and dermal condensate (DC), inducing hair follicle development.