Ortho-phenylphenol exposure impairs porcine sperm motility through AMPK/AKT signaling pathway

The natural flavonoid compound deguelin suppresses sperm (Sus Scrofa) functions through abnormal activation of the PI3K/AKT pathway

Deguelin is a natural flavonoid extracted from plants belonging to the Lonchocarpus, Derris, or Tephrosia genera. It inhibits AKT activity in tumors and has the potential to be used as a treatment for malignant tumors. However, the risks associated with the use of deguelin on male fertility have not yet been explained in detail. Therefore, this study was conducted to investigate the effects of deguelin on sperm functions during capacitation. First, boar spermatozoa were exposed to different concentrations of deguelin (0.1, 1, 10, 50, and 100 μM). Next, sperm functional assessments, such as sperm motility, capacitation status, intracellular ATP level, and cell viability, were performed. The expression levels of PI3K/AKT-related proteins and the phosphorylation of their tyrosine residues were also evaluated by western blotting. No significant difference was observed in cell viability; however, deguelin considerably decreased sperm motility and motion kinematics in a dose-dependent manner. Although no significant difference was observed in the capacitation status, acrosome reaction decreased at high concentrations of deguelin (50 and 100 μM). Furthermore, intracellular ATP levels were significantly decreased in all deguelin treatment groups compared with those in the control group. Results of western blotting revealed that deguelin substantially diminished tyrosine phosphorylation. Interestingly, in contrast to previous studies showing that deguelin inhibits AKT activity, our results showed that it increased the expression of PI3K/AKT pathway-related proteins. Collectively, these findings indicate that deguelin exerts negative effects on sperm functions due to abnormal PI3K/AKT signaling activation. We believe that this is the first study to provide evidence that deguelin can regulate sperm functions independent of PI3K/AKT pathway inhibition. Furthermore, its detrimental effects on male fertility should be considered while developing or using deguelin as a therapeutic agent.

Microcystin leucine arginine induces human sperm damage: Involvement of the Ca2+/CaMKKβ/AMPK pathway

As a common pollutant in the water environment, microcystin leucine arginine (MC-LR) can enter semen and damage the sperm in animals. However, the mechanism by which MC-LR damages human sperm is unclear. Therefore, human sperm samples were obtained from the Henan Provincial Sperm Bank and exposed to different concentrations (0, 1, 10, and 100 μg/L) of MC-LR for 1, 2, 4, and 6 h, to invegest the effects and potential mechanism of MC-LR on sperm. The results showed that MC-LR mainly accumulated in the neck and flagellum of human sperm. Compared to the control group, the sperm capacitation rate and motility were significantly decreased in the 100 μg/L group. After exposure of 100 μg/L of MC-LR, the central microtubule and microtubule doublet of sperm flagellum were blurred, asymmetrical, or even lost. Furthermore, the expression levels of flagellin DNAH17, SPEF2, SPAG16, SPAG6, and CFAP44 in human sperm were reduced. Also, the phosphorylation levels of CaMKKβ and AMPK can be inhibited by MC-LR. These findings revealed that MC-LR can induce functional and structural damage in human sperm, and the Ca²⁺/CaMKKβ/AMPK pathway may be involved in this process. This study will provide a basis for prevention and treatment of male fertility declines caused by MC-LR.

Establishment of a repertoire of fertility associated sperm proteins and their differential abundance in buffalo bulls (Bubalus bubalis) with contrasting fertility

Sperm harbours a wide range of proteins regulating their functions and fertility. In the present study, we made an effort to characterize and quantify the proteome of buffalo bull spermatozoa, and to identify fertility associated sperm proteins through comparative proteomics. Using high-throughput mass spectrometry platform, we identified 1305 proteins from buffalo spermatozoa and found that these proteins were mostly enriched in glycolytic process, mitochondrial respiratory chain, tricarboxylic acid cycle, protein folding, spermatogenesis, sperm motility and sperm binding to zona pellucida (p < 7.74E-08) besides metabolic (p = 4.42E-31) and reactive oxygen species (p = 1.81E-30) pathways. Differential proteomic analysis revealed that 844 proteins were commonly expressed in spermatozoa from both the groups while 77 and 52 proteins were exclusively expressed in high- and low-fertile bulls, respectively. In low-fertile bulls, 75 proteins were significantly (p < 0.05) upregulated and 176 proteins were significantly (p < 0.05) downregulated; these proteins were highly enriched in mitochondrial respiratory chain complex I assembly (p = 2.63E-07) and flagellated sperm motility (p = 7.02E-05) processes besides oxidative phosphorylation pathway (p = 6.61E-15). The down regulated proteins in low-fertile bulls were involved in sperm motility, metabolism, sperm-egg recognition and fertilization. These variations in the sperm proteome could be used as potential markers for the selection of buffalo bulls for fertility.

Mechanisms of deleterious effects of some pesticide exposure on pigs

The increase in the size of the global population increases the food and energy demand, making the use of pesticides in agricultural and livestock industries unavoidable. Exposure to pesticides can be toxic to the non-target species, such as humans, wildlife, and livestock, in addition to the target organisms. Various chemicals are used in the livestock industry to control harmful organisms, such as insects, weeds, and parasites. Pigs are one of the most important food sources for humans. In addition, pigs can be used as promising models for assessing the risk of absorption of environmental pollutants through the skin and oral exposure since they are physiologically similar to humans. Exposure to numerous environmental pollutants, such as mycotoxins, persistent organic pollutants, and heavy metals, has been reported to adversely affect growth, fertility, and endocrine homeostasis in pigs. Various pesticides have been observed in porcine tissues, blood, urine, and processed foods; however, there is a lack of comprehensive understanding of their effects on porcine health. This review provides a comprehensive description of the characteristics of pesticides that pigs can be exposed to and how their exposure affects porcine reproductive function, intestinal health, and endocrine homeostasis in vivo and in vitro.

Sphingomyelin Synthase 2 Participate in the Regulation of Sperm Motility and Apoptosis

Sphingomylin participates in sperm function in animals, and also regulates the Akt and ERK signaling pathways, both of which are associated with the asthenospermia. Sphingomyelin synthase 2 (SMS2) is involved in the biosynthesis of sphingomylin. To determine the relationship between SMS2 and human sperm function, we analyzed the distribution of SMS2 in human sperm and testes, and SMS2 expression in patients with asthenospermia and normozoospermia; human sperm were treated with anti-SMS2, and the sperm motility, penetration ability into methylcellulose, capacitation and acrosome reaction, and sperm [Ca²⁺]i imaging were evaluated, while the Akt and ERK pathway and cleaved caspase 3 were also analyzed. Results showed that SMS2 was localized in the testis and human sperm, and the protein levels of normozoospermia were higher than asthenospermia. Inhibition of SMS2 activity significantly decreased sperm motility and penetration ability into methylcellulose, but had no influence on capacitation and acrosome reaction, or on intracellular [Ca²⁺]i compared to IgG-treated control groups. Moreover, the phosphorylation level of Akt was decreased, whereas the phosphorylation of ERK and cleaved-caspase 3 levels were significantly increased. Taken together, SMS2 can affect sperm motility and penetration ability into methylcellulose, and participate in apoptosis associated with the Akt and ERK signaling pathways.

Neonatal exposure to organophosphorus flame retardant TDCPP elicits neurotoxicity in mouse hippocampus via microglia-mediated inflammation in vivo and in vitro

Tris(1,3-dichloro-2-propyl) phosphate (TDCPP) is a phosphorus-based flame retardant common in consumer goods and baby products. Concerns have been raised about TDCPP exposure and neurodevelopmental toxicity. However, the mechanism and early response for TDCPP-induced neurotoxicity are poorly understood. This study investigates the role of microglia-mediated neuroinflammation in TDCPP-induced neurotoxicity in mice and primary cells. TDCPP was administered to C57BL/6 pups (0, 5, or 50 mg/kg/day) via an oral gavage from postnatal days 10-38 (28 days). The results showed that TDCPP exposure for 28 days altered the gene expression of neuronal markers Tubb3, Nefh, and Nes, and led to apoptosis in the hippocampus. The mRNA levels of pro-inflammatory factors Il-1β, Tnfα and Ccl2 dose dependently increased in the hippocampus at both 24 h and 28 days following exposure, accompanied by microglia activation characterized by an amoeboid-like phenotype. In in vitro studies using the primary microglia isolated from neonatal mice, exposure to TDCPP (0-100 μM) for 24 h resulted in cellular activation. It also increased the expression of genes responsible for inflammatory responses including surface markers and pro-inflammatory cytokines. These changes occurred in a dose-dependent fashion. Neurite outgrowth of primary mouse hippocampal neurons was inhibited by treatment with the conditioned medium harvested from microglia exposed to TDCPP. These results reveal that neonatal exposure to TDCPP induces neuronal damage through microglia-mediated inflammation. This provides insight into the mechanism of TDCPP's neurodevelopmental toxicity, and suggests that microglial cell is a sensitive responder for OPFRs exposure.