Comparison of miRNA transcriptomes reveals differential regulation at four different ages in Sika Deer testes

To elucidate the complex physiological process of testis development and spermatogenesis in Sika deer, this study evaluated the changes of miRNA profiles in the four developmental stages of testis the juvenile (1-year-old), adolescence (3-year-old), adult (5-year-old) and aged (10-year-old) stages. The results showed that total total of 198 mature and 66 novel miRNAs were obtained. 88 (43 up and 45 down), 102 (44 up and 58 down), 54 (18 up and 36 down) DE miRNAs were identified in 3-vs.1-, 5-vs.3- and 10-vs.5-year-old testes, respectively. By integrating miRNA expression profiles, we predicted 69883 miRNA-mRNA interaction sites. The target genes were enriched by GO and KEGG pathways to obtain DE miRNA (miR-145, miR-140, miR-7, miR-26a, etc.), which play an important role in testis development and spermatogenesis. The data show that DE miRNAs could regulate testis developmental and spermatogenesis through signaling pathways, including MAPK signaling pathway, p53 signaling pathway, PI3K-Akt signaling pathway, Hippo signaling pathway, etc. It provides a useful resource for future studies on the role of miRNA regulation in testis development and spermatogenesis. The miRNA expression profiles of testicular tissues at 1, 3, 5, and 10-year-old in sika deer were generated by Illumina HiSeq2500 sequencing