miRNA-Profiling in Ejaculated and Epididymal Pig Spermatozoa and Their Relation to Fertility after Artificial Insemination

Abstract

MicroRNAs (miRNAs) are short non-coding RNAs (20–25 nucleotides in length) capable of regulating gene expression by binding -fully or partially- to the 3’-UTR of target messenger RNA (mRNA). To date, several studies have investigated the role of sperm miRNAs in spermatogenesis and their remaining presence toward fertilization and early embryo development. However, little is known about the miRNA cargo in the different sperm sources and their possible implications in boar fertility. Here, we characterized the differential abundance of miRNAs in spermatozoa from the terminal segment of the epididymis and three different fractions of the pig ejaculate (sperm-peak, sperm-rich, and post-sperm rich) comparing breeding boars with higher (HF) and lower (LF) fertility after artificial insemination (AI) using high-output small RNA sequencing. We identified five sperm miRNAs that, to our knowledge, have not been previously reported in pigs (mir-10386, mir-10390, mir-6516, mir-9788-1, and mir-9788-2). Additionally, four miRNAs (mir-1285, mir-92a, mir-34c, mir-30), were differentially expressed among spermatozoa sourced from ejaculate fractions and the cauda epididymis, and also different abundance was found between HF and LF groups in mir-182, mir-1285, mir-191, and mir-96. These miRNAs target genes with key roles in fertility, sperm survival, immune tolerance, or cell cycle regulation, among others. Linking the current findings with the expression of specific sperm proteins would help predict fertility in future AI-sires.

Comprehensive analysis of the differential expression of mRNAs, lncRNAs, and miRNAs in Zi goose testis with high and low sperm mobility

“…In our study, we observed a significant upregulation of miR-182-5p expression in the high-SMR group that was positively correlated with SM. These findings are consistent with the results reported by Ding et al (2020) and Martinez et al (2022) . A possible explanation is that miR-182-5p can reportedly inhibit inflammatory responses and regulate physiological apoptosis during spermatogenesis in the testis ( Qin, et al, 2018 ; Zhang, et al, 2018 ; Fei, et al, 2021 ; Wang, et al, 2024 ).…”

“… Ding et al (2020) found a positive correlation between the expression level of miR-182-5p and normal sperm morphology numbers in individuals with teratozoospermia ( TZ ), suggesting its potential use as a biomarker for TZ. Martinez et al (2022) and Curry et al (2011) reported that sperm with high miR-182-5p expression maintain high motility and integrity. In our study, we observed a significant upregulation of miR-182-5p expression in the high-SMR group that was positively correlated with SM.…”

QTLs and Candidate Genes Associated with Semen Traits in Merino Sheep

“…Similarly, a GWAS involving semen volume and number of sperm collected from Holstein-Friesian bulls identified several candidate genes such as GALC, PHF7, and PRKCD, all of which have been previously identified to play a role in spermatogenesis [38]. Similar investigations in pigs have identified several putative candidates associated with post-thaw motility and membrane integrity, including PLBD1, OXSR1, and EML5 [39], and polymorphisms in such genes have been previously reported to be associated with fertilisation in humans [40], spermatozoal motility in pigs [41], and spermatogenesis in bulls [42], respectively. Despite several past GWAS focused on identifying genomic regions and candidate genes associated with semen traits across a wide range of livestock species, the only previous study in sheep was conducted using Assaf rams [6], and there are no studies involving other common sheep breeds like the Merino.…”

Epigenetic Alterations in Cryopreserved Human Spermatozoa: Suspected Potential Functional Defects

“…The problem of sample size has always been an objective problem in related research of human gametes. For example, some sperm proteomics studies can only detect single-digit samples [76,77], and sperm transcriptome analysis also has objective limitations.…”