Comprehensive Profiling of Circular RNAs in Goat Dermal Papilla Cells and Prediction of Their Modulatory Roles in Hair Growth

Circular RNAs (circRNAs) are capable of finely modulating gene expression at transcriptional and post-transcriptional levels; however, their characters in dermal papilla cells (DPCs)-the signaling center of hair follicle-are still obscure. Herein, we established a comprehensive atlas of circRNAs in DPCs and their skin counterparts-dermal fibroblasts (DFs)-from cashmere goats. In terms of the results, a sum of 3706 circRNAs were bioinformatically identified. Subsequent analysis suggested that the detected transcripts exhibited several prominent genomic features, including exons as their main sources. Compared with DFs, 76 circRNAs significantly displayed higher abundances in goat DPCs, with 45 transcripts markedly exhibiting adverse trends (p < 0.05). Furthermore, potential roles and underlying molecular mechanisms of circRNAs in goat DPCs were speculated through constructing their possible regulatory networks with mRNAs and microRNAs (miRNAs). We found that the circRNAs may serve as miRNA sponges to alleviate three hair growth-related functional genes (HOXC8, RSPO1, and CCBE1) of DPCs from miRNAs-imposed post-transcriptional modulation, further facilitating two critical processes (HOXC8 and RSPO1: hair follicle stem cell activation; CCBE1: follicular angiogenesis) closely involved in hair growth. In addition, we also speculated that two intron-derived circRNAs (chi circ 0005569 and chi circ 0005570) possibly affect the expression of their host gene CCBE1 at a transcriptional level in the nucleus. The above results demonstrated that circRNAs are abundantly expressed in goat DPCs, and certain circRNAs are potential participators in hair growth via the effects on the levels of related functional genes. Our study offers a preliminary clue for researchers hoping to untangle the roles of non-coding RNAs in hair growth.