Maternal exposure to PM2.5 induces the testicular cell apoptosis in offspring triggered by the UPR-mediated JNK pathway

Melatonin ameliorates PM2.5-induced spermatogenesis disorder by preserving H3K9 methylation and SIRT3

There was a link between exposure to PM2.5 and male infertility. Melatonin has beneficial effects on the male reproductive processes. How PM2.5 caused spermatogenesis disturbance and whether melatonin could prevent PM2.5-induced reproductive toxicity have remained unclear. The results showed that PM2.5 could inhibit the Nrf2-mediated antioxidant pathway and distinctly increase the cell apoptosis in testes. Moreover, PM2.5 also perturbed the process of meiosis by modulating meiosis-associated proteins such as γ-H2AX and Stra8. Mechanistically, PM2.5 inhibited G9a-dependent H3K9 methylation and SIRT3-mediated p53 deacetylation, which consistent with decreased sperm count and motility rate in ApoE-/- mice. Further investigation revealed melatonin effectively alleviated PM2.5-induced meiosis inhibition by preserving H3K9 methylation. Melatonin also alleviated PM2.5-induced apoptosis by regulating SIRT3-mediated p53 deacetylation. Overall, our study revealed PM2.5 resulted in spermatogenesis disorder by perturbing meiosis via G9a-dependent H3K9 di-methylation and causing cell apoptosis via SIRT3/p53 deacetylation pathway and provided promising insights into the protective role of melatonin in air pollution associated with male infertility.

PM 2.5 juvenile exposure-induced spermatogenesis dysfunction by triggering testes ferroptosis and antioxidative vitamins intervention in adult male rats

PM2.5 derived from automobile exhaust can cause reproductive impairment in adult males, but the toxic effects of PM2.5 exposure on reproductive function in juvenile male rats and its relationship with ferroptosis have not been reported. In this paper, 30-day-old juvenile male Sprague-Dawley (SD) rats were divided into four groups (blank control, vitamin control, PM2.5, and PM2.5+Vitamin). The blank control group was fed normally, and the vitamin control group was given intragastric administration of vitamins in addition to normal feeding. PM2.5 was administered via tracheal intubation. When the rats were treated for 4 weeks until reaching the period of sexual maturity. A mating test was performed first, and then their testicular and epididymal tissues were studied. Compared with control rats, juvenile male rats exposed to PM2.5 showed a decreased sperm count and fertility rate, redox imbalance, damaged mitochondria, a metabolic disorder of intracellular iron ions, and a significant rise in ferroptosis during the period of sexual maturity. After antioxidative vitamins intervention, the redox imbalance, metabolic disorder of intracellular iron ions, and ferroptosis were all alleviated, leading to the following conclusions: after being exposed to PM2.5 from automobile exhaust, male juvenile rats during the period of sexual maturity have significantly decreased reproductive function. The reproductive toxicity of PM2.5 is closely related to oxidative stress and ferroptosis. In addition, ferroptosis decreases and reproductive function is recovered to some degree after antioxidative vitamins intervention.

Impacts and potential mechanisms of fine particulate matter (PM2.5) on male testosterone biosynthesis disruption

Exposure to PM2.5 is the most significant air pollutant for health risk. The testosterone level in male is vulnerable to environmental toxicants. In the past, researchers focused more attention on the impacts of PM2.5 on respiratory system, cardiovascular system, and nervous system, and few researchers focused attention on the reproductive system. Recent studies have reported that PM2.5 involved in male testosterone biosynthesis disruption, which is closely associated with male reproductive health. However, the underlying mechanisms by which PM2.5 causes testosterone biosynthesis disruption are still not clear. To better understand its potential mechanisms, we based on the existing scientific publications to critically and comprehensively reviewed the role and potential mechanisms of PM2.5 that are participated in testosterone biosynthesis in male. In this review, we summarized the potential mechanisms of PM2.5 triggering the change of testosterone level in male, which involve in oxidative stress, inflammatory response, ferroptosis, pyroptosis, autophagy and mitophagy, microRNAs (miRNAs), endoplasmic reticulum (ER) stress, and N6-methyladenosine (m6A) modification. It will provide new suggestions and ideas for prevention and treatment of testosterone biosynthesis disruption caused by PM2.5 for future research.

Triphenyl phosphate induced reproductive toxicity through the JNK signaling pathway in Caenorhabditis elegans

Triphenyl phosphate (TPHP) is a widely used aryl organophosphate flame retardant (OPFR) that has attracted attention due to its frequent detection in the environment and living organisms. To date, the reproductive toxicity of TPHP has been investigated in organisms, but its molecular mechanisms are not fully understood. Caenorhabditis elegans (C. elegans) is the ideal animal for the study of reproductive toxicity following environmental pollutants, with short generation times, intact reproductive structures, and hermaphroditic fertilization. This study aimed to explore the reproductive dysfunction and molecular mechanisms induced by TPHP exposure in C. elegans. Specifically, exposure to TPHP resulted in a reduction in the number of eggs laid and developing embryos in utero, an increase in the number of apoptotic gonadal cells, and germ cell cycle arrest. The JNK signaling pathway is a potential pathway inducing reproductive toxicity following TPHP exposure based on transcriptome sequencing (RNA-seq). Moreover, TPHP exposure induced down-regulation of vhp-1 and kgb-2 gene transcription levels, and the knockout of vhp-1 and kgb-2 in the mutant strains exhibited more severe toxicity in apoptotic gonad cells, embryos, and eggs developing in utero, suggesting that vhp-1 and kgb-2 genes play a crucial role in TPHP-induced reproductive toxicity. Our data provide convergent evidence showing that TPHP exposure results in reproductive dysfunction through the JNK signaling pathway and improve our understanding of the ecotoxicity and toxicological mechanisms of aryl-OPFRs.

Maternal exposure to PM2.5 disrupting offspring spermatogenesis through induced sertoli cells apoptosis via inhibin B hypermethylation in mice

Particulate Matter 2.5 (PM_2.5) disrupts endocrine functions and may negatively affect sperm quality and quantity in males; however, the long-term effects and potential mechanisms of this effect are unknown. This study aimed to investigate the epigenetic mechanism of maternal exposure to PM_2.5-induced inhibin B hypermethylation in male offspring. In this experiment design, pregnant C57BL/6 mice were treated with two doses of PM_2.5 (4.8 and 43.2 mg/kg bw). The membrane control group was given a sampling membrane and the control group received nothing. Following the formation of the vaginal plug, intratracheal instillation of PM_2.5 was administered every three days until delivery of the pups. To assess the effect of PM_2.5 in vitro, TM4 cells, a Sertoli-like cell line, was treated with different concentrations (0, 25, 50, 100 μg/mL) of PM_2.5 for 24 h. The results displayed that Sperm motility, as well as the number of adult offspring, was decreased in the PM_2.5 exposed group relative to the untreated controls. Increased vacuolization was observed in the Sertoli cells of mice that were exposed to PM_2.5 in utero. The levels of inhibin and testosterone were reduced and the levels of LH and FSH increased in the PM_2.5 groups relative to the untreated controls. In vitro, PM_2.5 resulted in cell cycle inhibition as well as increased apoptosis in TM4 cells. Moreover, PM_2.5-induced inhibin B hypermethylation and activation of the p21/Cleaved Caspase-3 pathway resulted in TM4 cell apoptosis that was rescued through the use of a DNA methylation inhibitor. Together, our data suggest that prenatal exposure to PM_2.5 results in inhibin B hypermethylation and can activate the p21/Cleaved Caspase-3 pathway, resulting in Sertoli cell apoptosis, aberrant secretion of androgen binding protein, and decreased testosterone, thus resulting in the inhibition of spermatogenesis.

In addition to its endosomal escape effect, platycodin D also synergizes with ribosomal inactivation protein to induce apoptosis in hepatoma cells through AKT and MAPK signaling pathways

Efficient endosomal escape after cellular uptake is a major challenge for the clinical application of therapeutic proteins. To overcome this obstacle, several strategies have been used to help protein drugs escape from endosomes without affecting the integrity of the cell membrane. Among them, some triterpenoid saponins with special structures were used to greatly enhance the anti-tumor therapeutic effect of protein toxins. Herein, we demonstrated that platycodin D (PD), polygalacin D (PGD) and platycodin D2 (PD2) from Platycodonis Radix significantly enhanced the ability of MHBP (a type I ribosome-inactivating protein toxin MAP30 fused with a cell-penetrating peptide HBP) to induce apoptosis in hepatoma cells. Based on the results of co-localization of endocytosed EGFP-HBP with a lysosomal probe and Galectin-9 vesicle membrane damage sensor, we demonstrated that PD, PGD and PD2 have the ability to promote endosomal escape of endocytic proteins without affecting the integrity of the plasma membrane. Meanwhile, we observed that cholesterol metabolism plays an important role in the activity of PD by RNA-seq analysis and KEGG pathway enrichment analysis, and confirm that PD, PGD and PD2 enhance the anti-tumor activity of MHBP by inducing the redistribution of free cholesterol and inhibiting the activity of cathepsin B and cathepsin D. Finally, we found that PD synergized with MHBP to induce caspase-dependent apoptosis through inhibiting Akt and ERK1/2 signaling pathways and activating JNK and p38 MAPK signaling pathways. This study provides new insights into the application of PD in cancer therapy and provides efficient and promising strategies for the cytosolic delivery of therapeutic proteins.