Influence of the Season and Region Factor on Phosphoproteome of Stallion Epididymal Sperm

Epididymal maturation can be defined as a scope of changes occurring during epididymal transit that prepare spermatozoa to undergo capacitation. One of the most common post-translational modifications involved in the sperm maturation process and their ability to fertilise an oocyte is the phosphorylation of sperm proteins. The aim of this study was to compare tyrosine, serine, and threonine phosphorylation patterns of sperm proteins isolated from three subsequent segments of the stallion epididymis, during and out of the breeding season. Intensities of phosphorylation signals and phosphoproteins profiles varied in consecutive regions of the epididymis. However, significant differences in the phosphorylation status were demonstrated in case of endoplasmic reticulum chaperone BiP (75 and 32 kDa), protein disulfide-isomerase A3 (50 kDa), nesprin-1 (23 kDa), peroxiredoxin-5 (17 kDa), and protein bicaudal D homolog (15 kDa) for season x type of phosphorylated residues variables. Significant differences in the phosphorylation status were also demonstrated in case of endoplasmic reticulum chaperone BiP and albumin (61 kDa), protein disulfide-isomerase A3 (50 kDa), and protein bicaudal D homolog (15 kDa) for region x type of phosphorylated residues variables.

Influence of Risk Factors for Male Infertility on Sperm Protein Composition

Male infertility is a common health problem that can be influenced by a host of lifestyle risk factors such as environment, nutrition, smoking, stress, and endocrine disruptors. These effects have been largely demonstrated on sperm parameters (e.g., motility, numeration, vitality, DNA integrity). In addition, several studies showed the deregulation of sperm proteins in relation to some of these factors. This review inventories the literature related to the identification of sperm proteins showing abundance variations in response to the four risk factors for male infertility that are the most investigated in this context: obesity, diabetes, tobacco smoking, and exposure to bisphenol-A (BPA). First, we provide an overview of the techniques used to identify deregulated proteins. Then, we summarise the main results obtained in the different studies and provide a compiled list of deregulated proteins in relation to each risk factor. Gene ontology analysis of these deregulated proteins shows that oxidative stress and immune and inflammatory responses are common mechanisms involved in sperm alterations encountered in relation to the risk factors.

Telomere Signaling and Maintenance Pathways in Spermatozoa of Infertile Men Treated With Antioxidants: An in silico Approach Using Bioinformatic Analysis

Telomere shortening is considered as a marker of cellular senescence and it is regulated by various signaling pathways. Sperm telomere appears to play important role in its longevity and function. Antioxidant intake has been known to prevent the shortening of telomere. In the management of male infertility, antioxidants are commonly used to counterbalance the seminal oxidative stress. It is important to understand how antioxidants treatment may modulate telomere signaling in sperm. In the current study, we have identified 377 sperm proteins regulated by antioxidants based on data mining of published literature. Bioinformatic analysis revealed involvement of 399 upstream regulators and 806 master regulators associated with differentially expressed sperm proteins. Furthermore, upstream regulator analysis indicated activation of kinases (EGFR and MAPK3) and transcription factors (CCNE1, H2AX, MYC, RB1, and TP53). Hence, it is evident that antioxidant supplementation activates molecules associated with telomere function in sperm. The outcome of this in silico study suggests that antioxidant therapy has beneficial effects on certain transcription factors and kinases associated with sperm telomere maintenance and associated signaling pathways that may play an important role in the management of male factor infertility.

Difference of seminal plasma and sperm proteins in good and poor freezability boar ejaculates

The present study was performed to compare the expression of sperm proteins, i.e. triosephosphate isomerase (TPI) and acrosin binding protein (ACRBP) and seminal plasma proteins, i.e. glutathione peroxidase 5 (GPX5) and fibronectin 1 (FN1), in boar semen with good, moderate and poor freezability. The study was conducted by determining the protein contents in 32 sperm samples and 38 seminal plasma samples of semen. The ejaculated semen was divided into two portions: the first portion was centrifuged to separate the pellet of sperm from the seminal plasma and the second portion was cryopreserved. After thawing, the ejaculates were classified into three groups according to their post-thawed sperm motility: good (60.2 ± 1.7%), moderate (29.3 ± 2.0%) and poor (16.6 ± 2.2%) freezabilities. The expressions of GPX5 and FN1 in seminal plasma and TPI and ACRBP in sperm were determined using Western blot analysis. It was found that, for sperm proteins, the level of TPI was negatively correlated with the post-thawed total sperm motility (r = -0.38, P = 0.029). For seminal plasma proteins, the level of FN1 in the seminal plasma was positively correlated with the post-thawed total sperm motility (r = 0.37, P = 0.021) and progressive motility (r = 0.39, P = 0.016). The expression of GPX5 was not correlated with any of the frozen–thawed sperm qualities (P > 0.05). In conclusions, boar semen containing a high level of FN1 in seminal plasma has better freezability. Frozen–thawed sperm motility was positively correlated with the level of FN1 in boar seminal plasma and negatively correlated with TPI in boar spermatozoa.

Effect of Boar Sperm Proteins and Quality Changes on Field Fertility

This study aimed to evaluate boar sperm characteristics and proteins, in relation to their importance regarding in vivo fertility. Sixty-five ejaculates were used and 468 sows (parity ≥ 2) were inseminated. Sperm CASA kinetics, morphology, viability, DNA fragmentation, mitochondrial membrane potential, sperm membrane biochemical activity (HOST) and sperm proteins (Heat Shock Protein 90-HSP90, glutathione peroxidase-5-GPX5, Osteopontin 70-OPN70) were assessed and related to field fertility (number of live-born piglets—NLBP, litter size ≥ 12 piglets—LS, farrowing rate—FR). Statistical analysis was conducted with simple and multiple regression models. Simple regression analysis showed that immotile sperm (IM) significantly affected the NLBP and LS, explaining 6.7% and 6.5% of their variation, respectively. The HOST positive spermatozoa significantly affected the NLBP and LS, explaining 24.5% and 7.8% of their variation, respectively. Similarly, sperm with activated mitochondria significantly affected the NLBP, explaining 13.5% of its variation. Moreover, the OPN70 affected LS and FR, explaining 7.5% and 10.8% of their variation, respectively. Sperm GPX5 protein affected FR, explaining 6.7% of its variation. Multiple regression analysis showed that the combination of IM and/OPN70 explains 13.0% of the variation regarding LS, and the combination of GPX5 and OPN70 explains 13.6% of the variation regarding FR. In conclusion, the estimation of parameters IM, membrane biochemical activity, mitochondrial membrane potential, OPN and GPX5 can provide useful information regarding semen doses for field fertility.

Analysis of major sperm proteins in two nematode species from two classes, Enoplus brevis (Enoplea, Enoplida) and Panagrellus redivivus (Chromadorea, Rhabditida), reveal similar localization, but less homology of protein sequences than expected for Nematoda phylum

Major sperm proteins (MSP) are a nematode-specific system of motor proteins required for amoeboid sperm movement. A number of MSP genes vary in different nematode species, but encoded protein sequences reveal high homology between these proteins. In fact, all studies of MSPs localization and functions are based exclusively on the representatives of the order Rhabditida belonging to the nematode class Chromadorea, while MSP-driven sperm movement in Enoplea, another major clade of the phylum Nematoda is still unconfirmed. In this study, we found out the presence of MSPs in the enoplean nematode Enoplus brevis (Enoplida) and compared MSP localization in sperm of this species with the chromadorean nematode Panagrellus redivivus (Rhabditida). Then, we analyzed the putative MSP sequences of both species. Our results indicate that MSPs are presented in E. brevis spermatozoa and form filamentous structures after sperm activation, which may be considered as the evidence of their motor functions similar to those in the spermatozoa of chromadorean nematodes. We found that E. brevis MSPs show lower homology to known proteins of rhabditids which species reveal hyper-conservatism in MSP protein sequences. It reflects evidently more distant evolutionary relationships of Enoplea and Chromadorea than exist within Rhabditida order. Our data denote necessity of reconsideration of view on MSP evolution within Nematoda.