The current perspective on genetic and epigenetic factors in sperm maturation in the epididymis

Abstract

Male infertility affects approximately 30% of infertile couples. As spermatozoa mature in the epididymal lumen, their potential for mobility increases, and their protein, lipid and small RNA (sRNA) content changes, whereas capacitation and fertilisation take place in the female reproductive tract. Both of the latter processes are affected by maturation, because impaired maturation causes premature capacitation and fertilization. The epididymis produces a suitable environment for sperm maturation via ion transport, vesicle secretion and protein matrix formation. The microenvironment for sperm maturation varies in three broad segments: the caput, the corpus and the cauda epididymis. Epididymosomes transfer proteins, lipids and sRNAs from the epididymal epithelium to spermatozoa and genetic alterations of epididymal genes can lead to decreased sperm motility, morphological abnormalities of spermatozoa and subfertility. Genetic factors are involved in all aetiological categories in male infertility. However, studies conducted on the genes involved in epididymal functions are limited. The sRNA content of spermatozoa changes during epididymal migration, and these sRNAs play a role in embryo development and epigenetic inheritance. This review aims to clarify the role of the epididymal epithelium in the maturation of spermatozoa in light of the current molecular genomic knowledge.

Epigenetics Role in Spermatozoa Function: Implications in Health and Evolution—An Overview

“…Globally, the transcriptome increases and undergoes dramatic transformations [ 10 ]. For that reason, in the head and in the tail of the epididymis, the spermatozoa transcriptome shows different compositions [ 8 , 9 ]. The most prominent changes are the reduction of piRNAs, the increase of the tsRNAs, and the increase and diversification of the miRNAs [ 10 ].…”

“…The most prominent changes are the reduction of piRNAs, the increase of the tsRNAs, and the increase and diversification of the miRNAs [ 10 ]. Proteome, in turn, seems to have an important influence on the induction of latency and potential capabilities [ 9 ]. Some RNAs and proteins remain in the seminal fluid performing their roles [ 30 ].…”

“…The maturation and fertilization capacity develops along the journey of the spermatozoa from the seminiferous epithelium to the encounter with the oocyte. It leads the male gamete to a state of hyperactivation, which guarantees that the action of the spermatozoa occurs at the moment adequate and with a sufficient intensity of motility [ 9 ]. The most remarkable changes occur during epididymal storage, where a molecular interchange is established between the gametes and the epididymal epithelium, which results in spermatozoa and plasma seminal molecular content transformation [ 10 ].…”

Sperm Selection for ICSI: Do We Have a Winner?

“…When the sperm sample is retrieved by testicular aspiration (TESE) [ 73 ] or epididymal aspiration (MESA) [ 74 ], the spermatozoa might appear immotile due to the lack of complete maturation that takes place in the final tract of the epididymis [ 75 ].…”

Effect of Paternal Diet on Spermatogenesis and Offspring Health: Focus on Epigenetics and Interventions with Food Bioactive Compounds

“…Previously, the sperm epigenome was not of significant importance, as it was thought that, after fertilization, all epigenetic marks were erased. However, with the passing of the years and the advancement of science, studies have increasingly demonstrated that epigenetic information carried by spermatozoa can indeed be transmitted between generations [ 98 , 99 , 100 , 101 , 102 ].…”