Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Xianyang 712100, China.
Int J Mol Sci. 2020 May 28;21(11):3846. doi: 10.3390/ijms21113846.
Spermatogenesis is a complex biological process regulated by well-coordinated gene regulation, including MicroRNAs (miRNAs). miRNAs are endogenous non-coding ribonucleic acids (ncRNAs) that mainly regulate the gene expression at post-transcriptional levels. Several studies have reported miRNAs expression in bull sperm and the process of spermatogenic arrest in cattle and yak. However, studies for the identification of differential miRNA expression and its mechanisms during the developmental stages of testis still remain uncertain. In the current study, we comprehensively analyzed the expression of miRNA in bovine testes at neonatal (3 days after birth, = 3) and mature (13 months, = 3) stages by RNA-seq. Moreover, the role of bta-miR-146b was also investigated in regulating the proliferation and apoptosis of bovine male germline stem cells (mGSCs) followed by a series of experiments. A total of 652 miRNAs (566 known and 86 novel miRNAs) were identified, whereas 223 miRNAs were differentially expressed between the two stages. Moreover, an elevated expression level of bta-miR-146b was found in bovine testis among nine tissues, and the functional studies indicated that the overexpression of bta-miR-146b inhibited the proliferation of bovine mGSCs and promoted apoptosis. Conversely, regulation of bta-miR-146b inhibitor promoted bovine mGSCs proliferation. This study provides a basis for understanding the regulation roles of miRNAs in bovine testis development and spermatogenesis.
精子发生是一个复杂的生物学过程，受基因调控的良好协调，包括 microRNAs（miRNAs）。miRNAs 是内源性非编码核糖核酸（ncRNAs），主要在转录后水平调节基因表达。几项研究报道了牛精子中的 miRNAs 表达及其在牛和牦牛精子发生停滞过程中的作用。然而，关于鉴定睾丸发育阶段差异表达 miRNA 及其机制的研究仍不确定。在本研究中，我们通过 RNA-seq 全面分析了牛睾丸在新生（出生后 3 天，n = 3）和成熟（13 个月，n = 3）阶段的 miRNA 表达。此外，还研究了 bta-miR-146b 在调节牛雄性生殖干细胞（mGSCs）增殖和凋亡中的作用，随后进行了一系列实验。共鉴定出 652 个 miRNA（566 个已知和 86 个新 miRNA），其中 223 个 miRNA 在两个阶段之间差异表达。此外，在牛睾丸中的 9 种组织中发现 bta-miR-146b 的表达水平升高，功能研究表明，bta-miR-146b 的过表达抑制了牛 mGSCs 的增殖并促进了凋亡。相反，bta-miR-146b 抑制剂的调节促进了牛 mGSCs 的增殖。本研究为理解 miRNA 在牛睾丸发育和精子发生中的调控作用提供了基础。
