Epigenetic analysis of high and low motile sperm populations reveals methylation variation in satellite regions within the pericentromeric position and in genes functionally related to sperm DNA organization and maintenance in Bos taurus

Abstract

BackgroundSperm epigenetics is an emerging area of study supported by observations reporting that abnormal sperm DNA methylation patterns are associated with infertility. Here, we explore cytosine-guanine dinucleotides (CpGs) methylation in high (HM) and low motile (LM) Bos taurus sperm populations separated by Percoll gradient. HM and LM methylation patterns were investigated by bisulfite sequencing.ResultsComparison between HM and LM sperm populations revealed that methylation variation affects genes involved in chromatin organization. CpG Islands (CGIs), were highly remodelled. A high proportion of CGIs was found to be methylated at low/intermediate level (20–60%) and associated to the repetitive element BTSAT4 satellite. The low/intermediate level of methylation in BTSAT4 was stably maintained in pericentric regions of chromosomes. BTSAT4 was hypomethylated in HM sperm populations.ConclusionsThe characterization of the epigenome in HM and LM Bos taurus sperm populations provides a first step towards the understanding of the effect of methylation on sperm fertility. Methylation variation observed in HM and LM populations in genes associated to DNA structure remodelling as well as in a repetitive element in pericentric regions suggests that maintenance of chromosome structure through epigenetic regulation is probably crucial for correct sperm functionality.

Global Methylation and Protamine Deficiency in Ram Spermatozoa Correlate with Sperm Production and Quality but Are Not Influenced by Melatonin or Season

“…Specifically, the observed associations between protamine deficiency, sperm production, morphology, sperm DNA fragmentation and AMH concentration in seminal plasma suggest that sperm protamine deficiency may indicate testicular function. Similarly, our findings that sperm global methylation is linked to sperm motility, morphology and DNA fragmentation indicate that epigenetics may hold a role in ram sperm functionality, as similarly indicated in humans [65,68], cattle [63,67] and pigs [33]. Our observed correlations warrant further study in the ram in order to clarify the influence of external factors and environmental cues on global methylation and protamine status and to determine any subsequent effects upon fertility.…”

“…The present study revealed that global methylation in ram spermatozoa is correlated with sperm quality, with ejaculates with lower sperm motility and higher percentages of morphologically abnormal spermatozoa demonstrating greater levels of methylation. There are now several studies suggesting that both patterns and degree of methylation vary between highly and lowly motile sperm populations in the bull [63], normal and sub-fertile men [64][65][66] and high-and low-fertility buffalo [67]. The correlation between sperm global methylation and semen parameters is less explored in comparison to the relationship between methylation and fertility, with limited previous findings yet to definitively conclude the nature of the association between global methylation and semen parameters.…”

CircRNA Role and circRNA-Dependent Network (ceRNET) in Asthenozoospermia

“…SPZ-borne RNAs constitute a heterogeneous family of both coding and non-coding RNAs (40). Sperm epigenetic signature significantly changes in male infertility cases (10,(41)(42)(43)(44)(45). Using a microarray-based strategy, the mRNA fingerprint has been characterized in fertile men (9).…”

Parental Effects on Epigenetic Programming in Gametes and Embryos of Dairy Cows

“…In contrast, low planes of nutrition of young Holstein-Friesian bulls resulted in the retarded onset of puberty ( Byrne et al, 2018 ). Although epigenetic studies related to bull metabolic status is still missing, DNA methylation and histone modifications patterns were both reported to be associated with bull fertility ( Verma et al, 2015 ; Kropp et al, 2017 ; Kutchy et al, 2018 ; Capra et al, 2019 ; Ugur et al, 2019 ). Functional annotation of these alterations indicate that they might be involved in spermatogenesis and embryo development ( Verma et al, 2015 ; Ugur et al, 2019 ).…”