Department of Biomedical Sciences, The University of Guelph, Guelph, ON, Canada.
CReATe Fertility Centre, Toronto, ON, Canada.
Front Endocrinol (Lausanne). 2022 May 19;13:874371. doi: 10.3389/fendo.2022.874371. eCollection 2022.
Small non-coding RNAs have been linked to different phenotypes in bovine sperm, however attempts to identify sperm-borne molecular biomarkers of male fertility have thus far failed to identify a robust profile of expressed miRNAs related to fertility. We hypothesized that some differences in bull fertility may be reflected in the levels of different miRNAs in sperm. To explore such differences in fertility that are not due to differences in visible metrics of sperm quality, we employed Next Generation Sequencing to compare the miRNA populations in sperm from bulls with comparable motility and morphology but varying Sire Conception Rates. We identified the most abundant miRNAs in both populations (miRs -34b-3p; -100-5p; -191-5p; -30d-4p; -21-5p) and evaluated differences in the overall levels and specific patterns of isomiR expression. We also explored correlations between specific pairs of miRNAs in each population and identified 10 distinct pairs of miRNAs that were positively correlated in bulls with higher fertility and negatively correlated in comparatively less fertile individuals. Furthermore, 8 additional miRNA pairs demonstrated the opposite trend; negatively correlated in high fertility animals and positively correlated in less fertile bulls. Finally, we performed pathway analysis to identify potential roles of miRNAs present in bull sperm in the regulation of specific genes that impact spermatogenesis and embryo development. Together, these results present a comprehensive picture of the bovine sperm miRNAome that suggests multiple potential roles in fertility.
小非编码 RNA 与牛精子的不同表型有关，然而，试图鉴定与男性生育力相关的精子携带的分子生物标志物的尝试迄今为止未能确定与生育力相关的表达 miRNA 的稳健特征。我们假设，公牛生育力的一些差异可能反映在精子中不同 miRNA 的水平上。为了探索由于精子质量的可见指标差异而不是由于精子质量的可见指标差异而导致的生育力差异，我们采用下一代测序来比较具有可比运动性和形态但 sire 受孕率不同的精子中的 miRNA 群体。我们确定了两个群体中最丰富的 miRNAs（miRs-34b-3p；-100-5p；-191-5p；-30d-4p；-21-5p），并评估了整体水平和特定 isomiR 表达模式的差异。我们还探索了每个群体中特定 miRNA 对之间的相关性，并鉴定出 10 对在生育力较高的公牛中呈正相关而在生育力相对较低的个体中呈负相关的独特 miRNA 对。此外，另外 8 对 miRNA 对表现出相反的趋势；在高生育力动物中呈负相关，在生育力较低的公牛中呈正相关。最后，我们进行了途径分析，以鉴定存在于公牛精子中的 miRNA 在调节影响精子发生和胚胎发育的特定基因中的潜在作用。总之，这些结果提供了牛精子 miRNAome 的全面描述，表明其在生育力方面具有多种潜在作用。
