Integrated Analysis of miRNAs and mRNA Profiling Reveals the Potential Role of miRNAs in Sheep Hair Follicle Development

Background: Merino sheep have high wool production and excellent wool quality. The fleece of the Merino sheep is composed predominantly of wool fibers grown from hair follicles (HFs). The hair follicle is a complex biological system involved in a dynamic process governed by gene regulation. However, gene expression is regulated by microRNAs (miRNAs). miRNA inhibits posttranscriptional gene expression by specifically binding to target messenger RNA (mRNA) and plays an important role in regulating gene expression, the cell cycle and biological development sequences. The purpose of this study was to bind to mRNA via miRNA to identify key miRNAs and target genes related to hair follicle development. This will provide new and important insights into fundamental mechanisms that regulate cellular activity and cell fate decisions inside and outside of the skin. Results We analyzed miRNA data in skin tissues of 18 Merino sheep at four embryonic days (E65, E85, E105 and E135) and two postnatal days (D7 and D30) and identified 87 differentially expressed miRNAs (DE-miRNAs). These six stages were further divided into two types of developmental stages based on heatmap cluster analysis, and the results showed that DE-mRNAs in Stage A were closely related to hair follicle morphogenesis. Co-analysis of Stage A DE-mRNAs and DE-miRNAs found that 9 DE-miRNAs and 17 DE-mRNAs have targeting relationships in Stage A. In our study, we found that miR-23b and miR-133 could target and regulate ACVR1B and WNT10A. In dermal fibroblasts, overexpression of miR-133 significantly reduced the mRNA and protein expression levels of ACVR1B. Overexpression of miR-23b significantly reduced the mRNA and protein expression levels of WNT10A. Conclusion This study provides a new reference for the molecular basis of HF development and lays a foundation for further improving sheep HF breeding. miRNAs and target genes related to hair follicular development were found, which provided a theoretical basis for molecular breeding for the culture of fine wool sheep.