Mammalian spermatozoa must undergo capacitation, before becoming competent for fertilization. Despite its importance, the fundamental molecular mechanisms of capacitation are poorly understood. Therefore, in this study, we applied a proteomic approach for identifying capacitation-related proteins in boar spermatozoa in order to elucidate the events more precisely. 2-DE gels were generated from spermatozoa samples in before- and after-capacitation. To validate the 2-DE results, Western blotting and immunocytochemistry were performed with 2 commercially available antibodies. Additionally, the protein-related signaling pathways among identified proteins were detected using Pathway Studio 9.0. We identified Ras-related protein Rab-2, Phospholipid hydroperoxide glutathione peroxidase (PHGPx) and Mitochondrial pyruvate dehydrogenase E1 component subunit beta (PDHB) that were enriched before-capacitation, and NADH dehydrogenase 1 beta subcomplex 6, Mitochondrial peroxiredoxin-5, (PRDX5), Apolipoprotein A-I (APOA1), Mitochondrial Succinyl-CoA ligase [ADP-forming] subunit beta (SUCLA2), Acrosin-binding protein, Ropporin-1A, and Spermadhesin AWN that were enriched after-capacitation (>3-fold) by 2-DE and ESI-MS/MS. SUCLA2 and PDHB are involved in the tricarboxylic acid cycle, whereas PHGPx and PRDX5 are involved in glutathione metabolism. SUCLA2, APOA1 and PDHB mediate adipocytokine signaling and insulin action. The differentially expressed proteins following capacitation are putatively related to sperm functions, such as ROS and energy metabolism, motility, hyperactivation, the acrosome reaction, and sperm-egg interaction. The results from this study elucidate the proteins involved in capacitation, which may aid in the design of biomarkers that can be used to predict boar sperm quality.

Benzo(a)pyrene (BaP) is an endocrine toxicant that is widely distributed in the environment. The adverse effects of BaP on fertility are well documented, however its effects on fertility in the subsequent generations are not known. We aimed to investigate the transgenerational effects of BaP on male fertility in mice. Six-week-old male mice (F0) were orally administered BaP (1 or 10 mg/kg body weight) or corn oil, daily for 6 weeks. The male mice were mated with untreated female mice to produce F1 offspring. The F2 and F3 progeny were produced in a similar manner. Testes and spermatozoa were collected from 14-week-old F0, F1, F2 and F3 males in order to assess male fertility parameters, namely testis histology, sperm count, sperm motility and sperm penetration (sperm penetration assay). Oral administration of a high dose of BaP induced testicular malformation and decreased numbers of seminiferous tubules with elongated spermatids for three generations studied (i.e. F0 to F2) with significant decreases in F0 and F2. It also significantly decreased sperm motility in F0. BaP significantly decreased sperm count in the group treated with a high dose of BaP in all generations except the F3 generation. The sperm fertility index (SFI) also decreased significantly for two generations. Of the fertility parameters measured, sperm count and SFI were the more sensitive parameters in our study. Exposure to BaP decreases the fertilization potential of exposed males and has an adverse impact on sperm function and fertility in subsequent generations. The BaP effect on fertility can be described as a transgenerational effect for F2 generation.

Recent evidence has indicated that bacteria-derived extracellular vesicles (EVs) are important for host–microbe communication. The aims of the present study were to evaluate whether bacteria-derived EVs are excreted via the urinary tract and to compare the composition of bacteria-derived EVs in the urine of pregnant and non-pregnant women. Seventy-three non-pregnant and seventy-four pregnant women were enrolled from Dankook University and Ewha Womans University hospitals. DNA was extracted from urine EVs after EV isolation using the differential centrifugation method. 16S ribosomal RNA (16S rRNA) gene sequencing was performed using high-throughput 454 pyrosequencing after amplification of the V1–V3 region of the 16S rDNA. The composition of 13 taxa differed significantly between the pregnant and non-pregnant women. At the genus level, Bacillus spp. EVs were more significantly enriched in the urine of the pregnant women than in that of the non-pregnant women (45.61% vs 0.12%, respectively). However, Pseudomonas spp. EVs were more dominant in non-pregnant women than in pregnant women (13.2% vs 4.09%, respectively). Regarding the compositional difference between pregnant women with normal and preterm delivery, EVs derived from Ureaplasma spp. and the family Veillonellaceae (including Megasphaera spp.) were more abundant in the urine of preterm-delivered women than in that of women with normal deliveries. Taken together, these data showed that Bacillus spp. EVs predominate in the urine of pregnant women, whereas Pseudomonas spp. EVs predominate in the urine of non-pregnant women; this suggests that Bacillus spp. EVs might have an important role in the maintenance of pregnancy.

Sodium fluoride (NaF), an environmental pollutant, has been tested for its impact on fertility in several species of laboratory animals. A literature demonstrated that NaF adversely affects sperm motility, morphology, capacitation, and the acrosome reaction. However, the molecular mechanisms underlying these alterations have not yet been elucidated. Therefore, present study was designed to evaluate the regulatory pathways involved in the effect of NaF on sperm function and fertilization. In this in vitro study, mouse spermatozoa were incubated with a range of concentrations (2.5, 5, and 10 mm) of NaF for 90 min in media that support in vitro fertilization. Our results showed that NaF was associated with reduced intracellular ATP generation, motility, and motion kinematics. Likewise, short‐term exposure of spermatozoa to NaF significantly reduced the intracellular calcium concentration, protein kinase‐A activity, and tyrosine phosphorylation of sperm proteins, which were associated with a significant decrease in the rate of capacitation and the acrosome reaction. Finally, NaF significantly reduced the fertilization and blastocyst formation during early embryonic development. On the basis of these results, we propose that NaF reduces sperm motility, capacitation, and the acrosome reaction leading to poor fertilization and suppressed embryonic development.

Arginine vasopressin (VP) is neurohypophysial hormone has been implicated in stimulating contractile activity of the male reproductive tract in the testis. Higher levels of VP decrease sperm count and motility. However, very little is known about the involvement of VP in controlling mammalian reproductive process. The goal of this study was to confirm that effect of VP receptor (AVPR2) on sperm function in capacitation condition. Deamino [Cys 1, D-ArgS] vasopressin (dDAVP), an AVPR2 agonist that operates only on AVPR2, was used. Also, Mouse spermatozoa were incubated with various concentrations of dDAVP (10⁻¹¹–10⁻⁵ M) and sperm motility, capacitation status, Protein Kinase A activity (PKA), tyrosine phosphorylation, fertilization, and embryo development were assessed using computer-assisted sperm analysis, Combined Hoechst 33258/chlortetracycline fluorescence, Western blotting, and in vitro fertilization, respectively. AVPR2 was placed on the acrosome region and mid-piece in cauda epididymal spermatozoa, but the caput epididymal spermatozoa was mid-piece only. The high dDAVP treatment (10⁻⁸ and 10⁻⁵ M) significantly decreased sperm motility, intracellular pH and PKA substrates (approximately 55 and 22 kDa) and increased Ca²⁺ concentration. The highest concentration treatment significantly decreased PKA substrate (approximately 23 kDa) and tyrosine phosphorylation (approximately 30 kDa). VP detrimentally affected capacitation, acrosome reaction, and embryo development. Treatment with the lowest concentration (10⁻¹¹ M) was not significantly different. Our data have shown that VP stimulates ion transport across sperm membrane through interactions with AVPR2. VP has a detrimental effect in sperm function, fertilization, and embryonic development, suggesting its critical role in the acquisition of fertilizing ability of mouse spermatozoa. These research findings will enable further study to determine molecular mechanism associated with fertility in capacitation and fertilization. It is also an important pivotal precondition to the progress of diagnostic test to identify infertility and to apply male contraception.