Expression of miRNAs in Bull Spermatozoa Correlates with Fertility Rates (original) (raw)

MicroRNA in sperm from Duroc, Landrace and Yorkshire boars

Scientific Reports, 2016

Sperm contain microRNAs (miRNAs), which may have roles in epigenetic control. Regarding phylogenetic relationships among various swine breeds, Yorkshire and Landrace, are considered phenotypically and genetically very similar, but distinctly different from Duroc. The objective of the present study was to compare abundance of boar sperm miRNAs in these three breeds. Overall, 252 prioritized miRNAs were investigated using real-time PCR; relative expression of miRNAs in sperm was similar in Yorkshire and Landrace boars, but significantly different compared to Duroc. Seventeen miRNAs (hsa-miR-196a-5p, hsa-miR-514a-3p, hsa-miR-938, hsa-miR-372-3p, hsa-miR-558, hsa-miR-579-3p, hsa-miR-595, hsa-miR-648, hsa-miR-524-3p, hsa-miR-512-3p, hsa-miR-429, hsa-miR-639, hsa-miR-551a, hsa-miR-624-5p, hsa-miR-585-3p, hsa-miR-508-3p and hsa-miR-626) were downregulated (P < 0.05; fold regulation ≤−2) in Yorkshire and Landrace sperm, compared to Duroc sperm. Furthermore, three miRNAs (hsa-miR-9-5p, hsa-miR-150-5p, and hsa-miR-99a-5p) were significantly up-regulated in Yorkshire and Landrace sperm compared to Duroc sperm, However, 240 miRNAs were not significantly different (within + 2 fold) between Yorkshire and Landrace sperm. We concluded that miRNAs in sperm were not significantly different between Yorkshire and Landrace boars, but there were significant differences between those two breeds and Duroc boars. Furthermore, integrated target genes for selected down-regulated miRNAs (identified via an in-silico method) appeared to participate in spermatogenesis and sperm functions. MicroRNAs are non-coding RNAs that regulate gene expression at a post-transcriptional level and fine-tune expression of ~30% of all mammalian protein-coding genes 1. Mature miRNAs are single-stranded, with approximately 22 nucleotides 2. MicroRNA genes are substantially regulated (positively or negatively) by many transcription factors and other proteins, in a tissue-or development-specific manner. Similar to protein-coding genes, microRNA genes are transcribed by RNA polymerase II as large primary transcripts (pri-miRNA) and subsequently processed by RNase III enzyme Drosha to form ~70 nucleotide precursor microRNAs (pre-miRNAs). These pre-miRNAs are subsequently transported to the cytoplasm and processed by RNase III enzyme DICER to form mature miRNAs, which are incorporated into a ribonuclear protein to form a miRNA-induced silencing complex (miRISC) that mediates gene silencing 3. Post-transcriptional addition of nucleotides to the 3′ ends of pre-miRNAs or mature miRNAs affects miRNA stability or abundance 4. Pig domestication has generated several phenotypically distinct breeds, with large differences among breeds for some traits, including reproduction and meat production 5-7. Although selection for various environments has resulted in a wide variety of domestic pig breeds with apparently divergent phenotypes 8 , genetic variability of miRNA expression, which could be linked to post-transcriptional modifications, has not yet been well characterized. However, a few studies reported differential expression (among various pig breeds) of miRNAs in skeletal muscles 9 , kidneys 10 and lungs 11. The present investigation proposed that miRNA expression was not only influenced by stages of development within an individual, types of animal tissues, or age, but also by breed. Sperm concentration, vitality and motility, as well as semen volume in boars, differed significantly among breeds 12. For example, Piétrain boars had lower ejaculate volume and total sperm number, but higher sperm concentration than Large White boars 13,14. Furthermore, Piétrain boars produced semen with greater volume and total number of sperm, but lower sperm concentration than Duroc boars 14-16. Despite these known semen traits differences among breeds, differences in miRNAs have not been well characterized. There are indications that expression of sperm miRNAs were altered by environmental changes 17 and that sperm traits influenced sperm miRNA expression 18. A hallmark study 19 identified robust changes in miRNAs in mouse sperm induced

A Combined Flow Cytometric Semen Analysis and miRNA Profiling as a Tool to Discriminate Between High- and Low-Fertility Bulls

2021

Predicting bull fertility is one of the main challenges for the dairy breeding industry and artificial insemination (AI) centers. Semen evaluation performed in the AI center is not fully reliable to determine the level of bull fertility. Spermatozoa are rich in active miRNA. Specific sperm-borne miRNAs can be linked to fertility. The aim of our study is to propose a combined flow cytometric analysis and miRNA profiling of semen bulls with different fertility to identify markers that can be potentially used for the prediction of field fertility. Sperm functions were analyzed in frozen-thawed semen doses (CG: control group) and high-quality sperm (HQS) fraction collected from bulls with different field fertility levels (estimated relative conception rate or ERCR) by using advanced techniques, such as the computer-assisted semen analysis system, flow cytometry, and small RNA-sequencing. Fertility groups differ for total and progressive motility and in the abnormality degree of the chro...

Small RNA sequencing of cryopreserved semen from single bull revealed altered miRNAs and piRNAs expression between High- and Low-motile sperm populations

BMC genomics, 2017

Small RNAs present in bovine ejaculate can be linked to sperm abnormalities and fertility disorders. At present, quality parameters routinely used in semen evaluation are not fully reliable to predict bull fertility. In order to provide additional quality measurements for cryopreserved semen used for breeding, a method based on deep sequencing of sperm microRNA (miRNA) and Piwi-interacting RNA (piRNA) from individual bulls was developed. To validate our method, two populations of spermatozoa isolated from high and low motile fractions separated by Percoll were sequenced, and their small RNAs content characterized. Sperm cells from frozen thawed semen samples of 4 bulls were successfully separated in two fractions. We identified 83 miRNAs and 79 putative piRNAs clusters that were differentially expressed in both fractions. Gene pathways targeted by 40 known differentially expressed miRNAs were related to apoptosis. Dysregulation of miR-17-5p, miR-26a-5p, miR-486-5p, miR-122-5p, miR-1...

Changes in miRNA levels of sperm and small extracellular vesicles of seminal plasma are associated with transient scrotal heat stress in bulls

Theriogenology, 2021

Scrotal heat stress affects spermatogenesis and impairs male fertility by increasing sperm morphological abnormalities, oxidative stress and DNA fragmentation. While sperm morpho-functional changes triggered by scrotal heat stress are well described, sperm molecular alterations remain unknown. Recently, spermatozoa were described as accumulating miRNAs during the last steps of spermatogenesis and through epididymis transit, mainly by communication with small extracellular vesicles (sEVs). Herein, the aim was to investigate the impact of scrotal heat stress in miRNAs profile of sperm, as well as, seminal plasma sEVs. Six Nelore bulls (Bos indicus) were divided into two groups: Control (CON; n ¼ 3) and Scrotal Heat Stress (SHS; n ¼ 3; scrotal heat stressed during 96 h by scrotal bags). The day that the scrotal bags were removed from SHS group was considered as D0 (Day zero). Seminal plasma sEVs were isolated from semen samples collected seven days after heat stress (Dþ7) to evaluate sEVs diameter, concentration, and 380 miRNA levels. Sperm morpho-functional features and profile of 380 miRNAs were evaluated from semen collected 21 days after heat stress (Dþ21). As a control, sEVs and sperm were analyzed seven days before heat stress (D-7). Only semen parameters that were not significantly different (P > 0.05) among bulls on D-7 were addressed on Dþ7 and Dþ21. While no alterations in diameter and concentration were detected in sEVs on Dþ7 between CON and SHS groups, three sEVs-miRNAs (miR-23b-5p, À489 and À1248) were down-regulated in SHS bulls compared to CON on Dþ7; other three (miR-126-5p, À656 and À1307) displayed a tendency (0.05 < P < 0.10) to be altered. Sperm oxidative stress was higher, and the level of 21 sperm miRNAs was altered (18 down-, 3 up-regulated) in SHS bulls compared to CON on Dþ21. Functional analysis indicated that target genes involved in transcription activation, as well as cell proliferation and differentiation were related to the 18 down-regulated sperm miRNAs (miR-9-5p,

Micro-RNAs differentially expressed in comparative analysis of sperm samples with high and low efficiency in the in vitro production of bovine (Bos Taurus) embryos

Bioscience Journal, 2019

Infertility or subfertility in bovine males may be related to spermatic microRNAs (miRNAs), whose function seems to be associated with the regulation of gene expression, degradation or storage of messenger RNAs (mRNAs) for later translation into early embryonic development. Thus, the purpose of this study was to identify differentially expressed miRNAs in semen samples from bulls (Bos taurus) with low and high efficiency in the in vitro embryo production (IVEP) and to evaluate if they can be used as markers of semen efficiency for IVEPs. In order to identify miRNA markers of semen efficiency in the in vitro embryo production, eight semen samples from each animal, one bull with high and two bulls with low efficiency in IVEPs were used to perform the RNAseq technique for miRNAs. Initially the samples were washed with PBS to remove the extender semen and subsequently were submitted to RNA extraction protocols performed according to procedures described by mirVanaâ„¢ miRNA Isolation Kit...

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

Biology

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-9...

An Investigation Into miRNAs in the Equine Epididymis as Potential Regulators of Spermatozoal Maturation

After spermatogenesis, spermatozoa are not mature and unable to fertilize an oocyte. During transition through the epididymis, spermatozoa mature, and gain fertility and motility. Although epididymal functions are relatively well known, the mechanisms behind maturation are not yet fully understood. Studies indicate proteins are delivered to the spermatozoa during epididymal transit through microvesicles. These microvesicles, called epididymosomes, carry microRNAs (miRNAs). These miRNAs are w22 nucleotides in length and regulate mRNA translation. The purpose of this study was to investigate which miRNAs are located within the various regions of stallion epididymal tissue. Three mature stallion epididymides were divided into four sections for miRNA isolation: the caput, proximal corpus, distal corpus and cauda. The contents of the lumen were removed and epididymal tissue was homogenized. Quantitative real-time polymerase chain reaction analysis was used to determine miRNA content. A total of 328 miRNAs were noted in epididymal tissue. A total of 186 of the 346 known equine miRNA transcripts used were found in each section, all four sections also contained miRNAs distinct to specific regions. The cauda contained the greatest number of exclusive miRNA (19) and expressed the greatest number of miRNA (282). This study shows there is indeed a difference in the miRNA profile between regions of the epididymis, and their targeted pathways may effect spermatozoal maturation.

Serum microRNAs in buffalo cows: Potential biomarkers of pregnancy

Research in veterinary science, 2017

MiRNAs (microRNA) constitute a large family of single-stranded, non-coding small RNAs. Although the functions and target genes of most miRNAs are still unknown, it has been well established that they are involved in embryogenesis, organogenesis and neonatal birth. In recent decades, interest in buffalo breeding has largely increased worldwide thus focusing the attention on this species as a dairy purpose animal. Problems related to long calving interval, late puberty and seasonal anestrus hamper reproductive efficiency in this species. Early pregnancy diagnosis is important to shorten the calving interval and increase lifetime production on dairy animals. MicroRNAs have recently emerged as key molecules in fertilization of several species even though in buffalo, few previous studies have investigated miRNAs. The aim of this research was to identify the best miRNA reference in serum among miR-191, miR-25-3p, SNORD44, and SNORD48. Consequently, assess the expression levels of miR-103,...

Involvement of miRNAs in equine follicle development

Reproduction, 2013

Previous evidence from in vitro studies suggests specific roles for a subset of miRNAs, including miR-21, miR-23a, miR-145, miR-503, miR-224, miR-383, miR-378, miR-132, and miR-212, in regulating ovarian follicle development. The objective of this study was to determine changes in the levels of these miRNAs in relation to follicle selection, maturation, and ovulation in the monovular equine ovary. In Experiment 1, follicular fluid was aspirated during ovulatory cycles from the dominant (DO) and largest subordinate (S) follicles of an ovulatory wave and the dominant (DA) follicle of a mid-cycle anovulatory wave (n=6 mares). Follicular fluid levels of progesterone and estradiol were lower (P<0.01) in S follicles than in DO follicles, whereas mean levels of IGF1 were lower (P<0.01) in S and DA follicles than in DO follicles. Relative to DO and DA follicles, S follicles had higher (P≤0.01) follicular fluid levels of miR-145 and miR-378. In Experiment 2, follicular fluid and granul...