Discovery and molecular analysis of conserved circRNAs from cashmere goat reveal their integrated regulatory network and potential roles in secondary hair follicle

Background: Circular RNAs, a novel class in the eukaryotic transcriptome, are characterized by the 3' and 5' ends that are covalently joined in a covalently closed loop without free ends. Circular RNAs are considerably stable molecules and act as microRNA sponges with regulatory potential to the protein-coding genes. Results: Eight circular RNAs were found to be significantly upregulated at anagen skin tissue of cashmere goat compared with their counterparts at telogen. Rich and complex regulatory patterns were revealed among the eight upregulated circular RNAs at anagen and related miRNAs with their potential regulatory genes. The potential regulatory genes of eight upregulated circular RNAs at anagen were involved in several pathways related to the main physiological process of hair follicle, such as histone acetylation and axon. For chi_circ_1926, chi_circ_3541, chi_circ_0483, chi_circ_3196, and chi_circ_2092, overall, the relative expression in secondary hair follicle exhibited highly similar trends with their corresponding host genes during the different stages of the hair follicle cycle. However, the expression trends of chi_circ_0100, chi_circ_2829, and chi_circ_1967 were found to diverge from their corresponding host genes during the different stages of the hair follicle cycle. Conclusions: A total of eighteen circular RNAs were identified and characterized from skin tissue of cashmere goat. The eight upregulated circular RNAs at anagen might have significant roles in the secondary hair follicle of cashmere goat. Our results would provide a novel regulatory layer to elucidate the molecular mechanisms underlying the development of secondary hair follicle and the growth of cashmere fiber in cashmere goat.

The effects of the method and dose of cyclophosphamide administration on cashmere shedding

The objective of this study was to investigate the effects of the method and dose of cyclophosphamide (CPA) administration on cashmere shedding. Thirty-two castrated Liaoning cashmere goats were randomly allotted to four groups, with eight replicates in each group. Goats in the four groups were injected intravenously or intramuscularly with CPA at doses of 20 or 25 mg kg−1 body weight (BW), respectively. Feed intake and BW were recorded, and erythrocyte count, hemoglobin content, and cashmere weight were determined. It was found that the CPA administration method had no significant effect on feed intake or BW of cashmere goats. Cyclophosphamide injection can significantly decrease the erythrocyte count and hemoglobin content of cashmere goats, but the effects are dependent on injection method and CPA dose. The injection method and dose did not significantly influence cashmere weight, but the method had significant effects on time to initiate shedding and regrown hair length. Regrown hair was longest by intramuscular injection with 20 mg kg−1 BW, which also caused the least erythema on the epidermis during the days after shedding. The results indicate that the CPA administration method can significantly influence cashmere shedding. Intramuscular injection of CPA at a dose of 20 mg kg−1 BW was found to be relatively beneficial for hair removal and regrowth in cashmere goats.(AU)