Novaluron Has Detrimental Effects on Sperm Functions

Nirmatrelvir has detrimental effects on sperm function by altering the PI3K/PDK1/AKT signaling pathway

Nirmatrelvir (NMV) is a recently developed selective inhibitor of the main protease of Sars-Cov-2 that reduces the severity of infection. Despite its widespread use and various side effects, NMV's effect on male fertility is still unclear. This study was thus established to investigate how NMV affects male fertility. For experiments, Duroc spermatozoa were incubated with various concentrations of NMV (0, 0.1, 1, 10, 50, and 100 μM). Then, sperm motility, motion kinematics, capacitation status, intracellular ATP level, and cell viability were evaluated. In addition, the expression levels of phospho-PKA substrates, tyrosine-phosphorylated proteins, and PI3K/PDK1/AKT signaling pathway-related proteins were measured by western blotting. Our results showed that sperm motility, motion kinematics, proportion of capacitated spermatozoa, and intracellular ATP level were significantly decreased by NMV in a dose-dependent manner. Moreover, PKA activation was significantly suppressed by NMV, and expression levels of PI3K, phospho-PDK1, AKT, and phospho-AKT (Thr308 and Ser473) were significantly increased in a dose-dependent manner. Combining these findings, it is suggested that NMV has detrimental effects on sperm function by inducing abnormal changes in the PI3K/PDK1/AKT signaling pathway, resulting in PKA deactivation. Therefore, there is a need to pay particular attention to its male reproductive toxicity when NMV is administered.

Adverse Effects of Avobenzone on Boar Sperm Function: Disruption of Protein Kinase A Activity and Tyrosine Phosphorylation

Avobenzone (AVO), an ultraviolet (UV) filter, is frequently used as an ingredient in personal cosmetics. This UV filter has been found to be easily exposed in swimming pools and beaches, and it has been detected in human urine and blood. Moreover, numerous studies have demonstrated that AVO exhibits endocrine-disrupting properties. Nevertheless, the effects of AVO on male fertility have not yet fully understood. Therefore, this study aimed to assess the effects of AVO on various sperm functions during capacitation. First, boar spermatozoa were treated with various AVO concentrations. After treatment, sperm motility and kinetic characteristics, capacitation status, intracellular adenosine triphosphate (ATP) levels, and sperm viability were evaluated. Moreover, Western blot analysis w.as conducted to evaluate protein kinase A (PKA) activity and tyrosine phosphorylation. As a result, AVO treatment significantly decreased total motility, progressive motility, and several kinetic characteristics at high concentrations (50 and 100 μM). Furthermore, the capacitation status dose-dependently decreased. Conversely, no significant differences in acrosome reaction, cell viability, and intracellular ATP levels were observed. However, the intracellular ATP level tended to decrease. In addition, AVO dose-dependently induced abnormal changes in PKA activity and tyrosine phosphorylation. Although AVO did not directly exert a toxic effect on cell viability, it ultimately negatively affected sperm functions through abnormal alterations in PKA activity and tyrosine phosphorylation. Thus, the potential implications on male fertility must be considered when contemplating the safe utilization of AVO.

Effect of 4-nonylphenol (4-NP) on sperm function: Insights into the PI3K/PDK1/AKT signaling pathway during capacitation

4-Nonylphenol (4-NP) is an endocrine-disrupting chemical that impairs animal and human reproduction. However, the mechanisms underlying male reproductive dysfunction by 4-NP have not been fully understood. Herein, we demonstrated the effects of 4-NP on boar sperm functions and molecular mechanisms. Spermatozoa were treated with various concentrations of 4-NP (0, 10, 25, 50, 75, and 100 μM) during capacitation. Then, we evaluated sperm motility, capacitation status, intracellular ATP level, and cell viability. Finally, we measured the expression of phosphorylated protein kinase A (PKA), tyrosine phosphorylation, and proteins related to the phosphatidylinositol 3 kinase (PI3K)/phosphoinositide-dependent kinase-1 (PDK1)/protein kinase B (AKT) signaling pathways following exposure to 4-NP. Sperm motility and motion kinematics were reduced by 4-NP, whereas intracellular ATP levels were increased significantly in a dose-dependent manner. Furthermore, the expression levels of p-PI3K, PTEN, p-PDK1, AKT, and p-AKT exhibited a significant dose-dependent increase. Moreover, abnormal activation of PKA and tyrosine phosphorylation were observed. Specifically, the ∼24 kDa p-PKA substrate demonstrated a significant reduction following exposure to 4-Np. In addition, the ∼18 kDa p-PKA substrate and tyrosine-phosphorylated proteins displayed a significant dose-dependent increase after exposure to 4-NP. Our results suggest that 4-NP may induce detrimental effects on sperm functions through abnormal changes in PKA activity and tyrosine phosphorylation during capacitation, possibly through unusual alteration of the PI3K/PDK1/AKT signaling pathway. Therefore, 4-NP must be cautiously used considering its reproductive toxicity.

Efficacy of the insect growth regulator novaluron in the control of dengue vector mosquitoes Aedes aegypti and Ae. albopictus

Insect Growth Regulator (IGR) novaluron is an alternative to synthetic neuro-inhibitory insecticides. Present study was designed to assess appropriate dosages of novaluron for dengue vector control. Larvae of Aedes aegypti and Ae. albopictus were exposed to a concentration series of novaluron (Rimon EC10) for two fixed exposure periods of 7-days and 14-days to determined LC50 and LC99 values. Inhibition of adult emergence (IE50 and IE99) was determined by a 14-day exposure. Semi-field experiments were conducted by exposing cohorts of Ae. aegypti larvae to IE99, 2 × IE99 and 10 × IE99 novaluron concentrations in water storage buckets (10 L) and plastic barrels (200 L). For the 7-day exposure, LC50 values were 0.047-0.049 ppm and LC99 were 0.144-0.151 ppm. For 14-day exposure, these values were 0.002-0.005 ppm and 0.006-0.01 ppm respectively. For both species, IE99 was 0.001 ppb under semi-field conditions, and was effective for nearly 2 months. Novaluron concentration 0.01 ppb was effective up to 3 months, with an IE of 89-95%. Authorities should critically review a reduction of the presently recommended field dosage of 200 ppm novaluron by × 100 or more. This would provide the same efficacy but mitigate environmental pollution, development of vector resistance, and financial losses.

Ritonavir Has Reproductive Toxicity Depending on Disrupting PI3K/PDK1/AKT Signaling Pathway

Ritonavir (RTV) is an antiviral and a component of COVID-19 treatments. Moreover, RTV demonstrates anti-cancer effects by suppressing AKT. However, RTV has cytotoxicity and suppresses sperm functions by altering AKT activity. Although abnormal AKT activity is known for causing detrimental effects on sperm functions, how RTV alters AKT signaling in spermatozoa remains unknown. Therefore, this study aimed to investigate reproductive toxicity of RTV in spermatozoa through phosphoinositide 3-kinase/phosphoinositide-dependent protein kinase-1/protein kinase B (PI3K/PDK1/AKT) signaling. Duroc spermatozoa were treated with various concentrations of RTV, and capacitation was induced. Sperm functions (sperm motility, motion kinematics, capacitation status, and cell viability) and expression levels of tyrosine-phosphorylated proteins and PI3K/PDK1/AKT pathway-related proteins were evaluated. In the results, RTV significantly suppressed sperm motility, motion kinematics, capacitation, acrosome reactions, and cell viability. Additionally, RTV significantly increased levels of phospho-tyrosine proteins and PI3K/PDK1/AKT pathway-related proteins except for AKT and PI3K. The expression level of AKT was not significantly altered and that of PI3K was significantly decreased. These results suggest RTV may suppress sperm functions by induced alterations of PI3K/PDK1/AKT pathway through abnormally increased tyrosine phosphorylation. Therefore, we suggest people who use or prescribe RTV need to consider its male reproductive toxicity.

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.

Reproductive Toxicity of Ritonavir in Male: insight into mouse sperm capacitation

Since COVID-19 began in 2019, therapeutic agents are being developed for its treatment. Among the numerous potential therapeutic agents, ritonavir (RTV), an anti-viral agent, has recently been identified as an important element of the COVID-19 treatment. Moreover, RTV has also been applied in the drug repurposing of cancer cells. However, previous studies have shown that RTV has toxic effects on various cell types. In addition, RTV regulates AKT phosphorylation within cancer cells, and AKT is known to control sperm functions (motility, capacitation, and so on). Although deleterious effects of RTV have been reported, it is not known whether RTV has male reproduction toxicity. Therefore, in this study, we aimed to investigate the effects of RTV on sperm function and male fertility. In the present study, sperm collected from the cauda epididymis of mice were incubated with various concentrations of RTV (0, 0.1, 1, 10, and 100 μM). The expression levels of AKT, phospho-AKT (Thr³⁰⁸ and Ser⁴⁷³), and phospho-tyrosine proteins, sperm motility, motion kinematics, capacitation status, and cell viability were assessed after capacitation. The results revealed that AKT phosphorylation at Thr³⁰⁸ and Ser⁴⁷³ was significantly increased, and the levels of tyrosine-phosphorylated proteins (at approximately 25 and 100 kDa) were significantly increased in a dose-dependent manner. In addition, RTV adversely affected sperm motility, motion kinematics, and cell viability. Taken together, RTV may have negative effects on sperm function through an abnormal increase in tyrosine phosphorylation and phospho-AKT levels. Therefore, individuals taking or prescribing RTV should be aware of its reproductive toxicity.

GRP78 plays a key role in sperm function via the PI3K/PDK1/AKT pathway

Glucose-regulated protein 78 (GRP78), which is commonly found in the endoplasmic reticulum (ER), is involved in stabilizing ER proteins and inducing the unfolded protein response. Furthermore, GRP78 is expressed on the surface of most common cancer cells, such as cells of breast, lung, liver, and prostate cancers, and plays a role in apoptosis and cell proliferation via the PI3K/PDK1/AKT signaling pathway. Therefore, various trials have been performed for evaluating cancer treatment by inhibiting GRP78. Moreover, GRP78 is expressed on the surface of spermatozoa; however, its role in spermatozoa physiology remains unclear. Therefore, this study was designed to investigate the effects of GRP78 on sperm function during capacitation and elucidate the underlying mechanisms. Boar spermatozoa were exposed to various concentrations of HA15, a GRP78 antagonist, and sperm kinematic parameters, capacitation status, cell viability, levels of PI3K/PDK1/AKT-pathway related proteins, and tyrosine phosphorylation were evaluated. GRP78 inhibition significantly decreased sperm motility, kinematic parameters, capacitated and acrosome-reacted spermatozoa counts, and cell viability. Moreover, GRP78 expression was significantly decreased in HA15-treated spermatozoa compared to that in the control group, and levels of PI3K/PDK1/AKT-pathway related proteins changed significantly. Furthermore, tyrosine phosphorylation was significantly altered in the HA15-treated group. The results of this study suggest that GRP78 inhibition in cancer therapy may negatively affect sperm function. These results lay a strong foundation for future studies aiming to identify the molecular mechanisms related to GRP78 in spermatozoa.