Screening and bioinformatics analysis of a potential ceRNA network in melatonin-induced cashmere growth in Liaoning...

The purpose of this study was to investigate the effect of melatonin (MT) on the expression patterns of lncRNA, mRNA and miRNA in Liaoning cashmere goat (LCG) skin fibroblasts. A quantity of 200 ng L ${}^{-1}$  MT (MT group) stimulated LCG skin fibroblasts for 48 h, and RNA sequencing was conducted with the control group (Con group) ( $n=3$ ). The ceRNA network was constructed by bioinformatics analysis of the sequencing data and transmission electron microscopy observation of coated pits and endocytic vesicles. In this study, the results indicated that MT treatment significantly facilitated the proliferation of LCG skin fibroblasts and increased the number of coated pits and vesicles. A total of 775 mRNAs, 57 lncRNAs and 10 miRNAs had differential expression, as indicated by RNA sequencing of skin fibroblasts administrated on the MT group and Con group. The regulatory network of ceRNA was studied, and the results suggested that inositol phosphate metabolism, the cGMP-PKG signaling pathway, endocytosis and other pathways played a certain role in the growth and development of the LCG cashmere. Moreover, the key genes (e.g., CREB1, PIK3C3, AGAP3, MEF2A, ASAP2, IRAG1, PNISR, PIP5K1A, SRSF11, ZRANB2, RBM39 and CBL) were regulated by chi-miR-34c-5p, chi-miR-34c-3p and chi-miR-195-5p. The above mRNAs were competitively bound by 15 lncRNAs (e.g., MSTRG.28630.12, MSTRG.28660.14, MSTRG.28099.7). And through dual luciferase and other experiments, it was further confirmed that PIP5K1A is the target gene of miR-34c-5p. This finding provides new insights into the molecular mechanism by which melatonin promotes villi growth in cashmere.