The endoplasmic reticulum stress and related signal pathway mediated the glyphosate-induced testosterone synthesis inhibition in TM3 cells

Chlorpyrifos-oxon induced neuronal cell death via endoplasmic reticulum stress-triggered apoptosis pathways

Chlorpyrifos (CPF) is one of the organophosphorus pesticides widely used throughout the world. Epidemiological studies suggested a link between CPF exposure and neurologic disorders, while the molecular mechanisms remain inconclusive. In the present study, we investigated the impacts of chlorpyrifos-oxon (CPO), the major toxic CPF metabolite, on cell apoptosis, and explored possible mechanism associated with endoplasmic reticulum (ER) stress in SH-SY5Y cells. Results showed that CPO exposure induced dose-dependent apoptosis and expression of ER stress-related proteins in SH-SY5Y cells. Pretreatment with 4-PBA (an ER stress inhibitor) effectively inhibited the expression of GRP78, GRP94, p-IRE1α, and XBP1-s, and apoptotic events. Pretreatment with STF-083010 (an IRE1α inhibitor) partially attenuated CPO-induced apoptosis. In addition, CPO exposure significantly evoked the generation of reactive oxygen species (ROS) which could be eliminated by pretreatment of 4-PBA. Of note, buffering the ROS generation with antioxidant NAC had little impact on the expression of p-IRE1α, and only partially attenuated CPO-induced apoptosis. In contrast, co-pretreatment with NAC and STF-083010 effectively inhibited CPO-induced apoptotic events. Collectively, our results indicate that CPO exposure exerts neuronal cytotoxicity via ER stress downstream-regulated IRE1α/XBP1 signaling pathway and ROS generation-triggered apoptosis. These findings highlight the role of ER stress in CPF-induced neurotoxicity, and provide a promising target for the intervention of organophosphate-associated neurodegenerative diseases.

Apigenin improves testosterone synthesis by regulating endoplasmic reticulum stress

Obesity is a growing epidemic among reproductive-age men, which can cause and exacerbate male infertility by means of associated comorbidities, endocrine abnormalities, and direct effects on the fidelity and throughput of spermatogenesis. A prominent consequence of male obesity is a reduction in testosterone levels. Natural products have shown tremendous potential anti-obesity effects in metabolic diseases. This study aimed to investigate the potential of apigenin (AP) to alleviate testicular dysfunction induced by a high-fat diet (HFD) and to investigate the underlying mechanisms, focusing on endoplasmic reticulum stress (ERS) and testosterone synthesis. A murine model of obesity was established using HFD-fed mice. The effects of AP on obesity, lipid metabolism, testicular dysfunction, and ERS were assessed through various physiological, histological, and molecular techniques. Administration of AP (10 mg/kg) ameliorated HFD-induced obesity and testicular dysfunction in a mouse model, as evidenced by decreased body weight, improved lipid profiles and testicular pathology, and restored protein levels related to testosterone. Furthermore, in vitro studies demonstrated that AP relieved ERS and recovered testosterone synthesis in murine Leydig cells (TM3) treated with free fatty acids (FFAs). It was also observed that AP rescued testosterone synthesis enzymes in TM3 cells, similar to that observed with the inhibitor of the PERK pathway (GSK2606414). In addition, ChIP, qPCR, and gene silencing showed that the C/EBP homologous protein (CHOP) bound directly to the promoter region of steroidogenic STAR and negatively modulated its expression. Collectively, AP has remarkable potential to alleviate HFD-induced obesity and testicular dysfunction. Its protective effects are attributable partly to mitigating ERS and restoring testosterone synthesis in Leydig cells.

Glyphosate presence in human sperm: First report and positive correlation with oxidative stress in an infertile French population

Environmental exposure to endocrine disruptors, such as pesticides, could contribute to a decline of human fertility. Glyphosate (GLY) is the main component of Glyphosate Based Herbicides (GBHs), which are the most commonly herbicides used in the world. Various animal model studies demonstrated its reprotoxicity. In Europe, GLY authorization in agriculture has been extended until 2034. Meanwhile the toxicity of GLY in humans is still in debate. The aims of our study were firstly to analyse the concentration of GLY and its main metabolite, amino-methyl-phosphonic acid (AMPA) by LC/MS-MS in the seminal and blood plasma in an infertile French men population (n=128). We secondly determined Total Antioxidant Status (TAS) and Total Oxidant Status (TOS) using commercial colorimetric kits and some oxidative stress biomarkers including malondialdehyde (MDA) and 8-hydroxy-2'-deoxyguanosine (8-OHdG) by ELISA assays. We next analysed potential correlations between GLY and oxidative stress biomarkers concentration and sperm parameters (sperm concentration, progressive speed, anormal forms). Here, we detected for the first time GLY in the human seminal plasma in significant proportions and we showed that its concentration was four times higher than those observed in blood plasma. At the opposite, AMPA was undetectable. We also observed a strong positive correlation between plasma blood GLY concentrations and plasma seminal GLY and 8-OHdG concentrations, the latter reflecting DNA impact. In addition, TOS, Oxidative Stress Index (OSI) (TOS/TAS), MDA blood and seminal plasma concentrations were significantly higher in men with glyphosate in blood and seminal plasma, respectively. Taken together, our results suggest a negative impact of GLY on the human reproductive health and possibly on his progeny. A precaution principle should be applied at the time of the actual discussion of GLY and GBHs formulants uses in Europe by the authorities.

Protein quality control systems in the endoplasmic reticulum and the cytosol coordinately prevent alachlor-induced proteotoxic stress in Saccharomyces cerevisiae

Alachlor, a widely used chloroacetanilide herbicide for controlling annual grasses in crops, has been reported to rapidly trigger protein denaturation and aggregation in the eukaryotic model organism Saccharomyces cerevisiae. Therefore, this study aimed to uncover cellular mechanisms involved in preventing alachlor-induced proteotoxicity. The findings reveal that the ubiquitin-proteasome system (UPS) plays a crucial role in eliminating alachlor-denatured proteins by tagging them with polyubiquitin for subsequent proteasomal degradation. Exposure to alachlor rapidly induced an inhibition of proteasome activity by 90 % within 30 min. The molecular docking analysis suggests that this inhibition likely results from the binding of alachlor to β subunits within the catalytic core of the proteasome. Notably, our data suggest that nascent proteins in the endoplasmic reticulum (ER) are the primary targets of alachlor. Consequently, the unfolded protein response (UPR), responsible for coping with aberrant proteins in the ER, becomes activated within 1 h of alachlor treatment, leading to the splicing of HAC1 mRNA into the active transcription activator Hac1p and the upregulation of UPR gene expression. These findings underscore the critical roles of the protein quality control systems UPS and UPR in mitigating alachlor-induced proteotoxicity by degrading alachlor-denatured proteins and enhancing the protein folding capacity of the ER.

Melatonin alleviates glyphosate-induced testosterone synthesis inhibition via targeting mitochondrial function in roosters

Glyphosate (GLY) is a widely used herbicide that has been revealed to inhibit testosterone synthesis in humans and animals. Melatonin (MET) is an endogenous hormone that has been demonstrated to promote mammalian testosterone synthesis via protecting mitochondrial function. However, it remains unclear whether MET targets mitochondria to alleviate GLY-inhibited testosterone synthesis in avian. In this study, an avian model using 7-day-old rooster upon chronic exposure to GLY with the treatment of MET was designed to clarify this issue. Data first showed that GLY-induced testicular Leydig cell damage, structural damage of the seminiferous tubule, and sperm quality decrease were mitigated by MET. Transcriptomic analyses of the testicular tissues revealed the potentially critical role of mitophagy and steroid hormone biosynthesis in the process of MET counteracting GLY-induced testicular damage. Also, validation data demonstrated that the inhibition of testosterone synthesis due to GLY-induced mitochondrial dynamic imbalance and concomitant Parkin-dependent mitophagy activation is alleviated by MET. Moreover, GLY-induced oxidative stress in serum and testicular tissue were significantly reversed by MET. In summary, these findings demonstrate that MET effectively ameliorates GLY-inhibited testosterone synthesis by inhibiting mitophagy activation, which provides a promising remedy for the application of MET as a potential therapeutic agent to antagonize reproductive toxicity induced by GLY and similar contaminants.

Integrated Studies on Male Reproductive Toxicity of Bis(2-ethylhexyl)-tetrabromophthalate: in Silico, in Vitro, ex Vivo, and in Vivo

Bis(2-ethylhexyl)tetrabromophthalate (TBPH) has been widely detected in the environment and organisms; thus, its toxic effects on male reproduction were systematically studied. First, we found that TBPH can stably bind to the androgen receptor (AR) based on in silico molecular docking results and observed an antagonistic activity, but not agonistic activity, on the AR signaling pathway using a constructed AR-GRIP1 yeast assay. Subsequently, we validated the adverse effects on male germ cells by observing inhibited androgen production and proliferation in Leydig cells upon in vitro exposure and affected general motility and motive tracks of zebrafish sperm upon ex vivo exposure. Finally, the in vivo reproductive toxicity was demonstrated in male zebrafish by reduced mating behavior in F0 generation when paired with unexposed females and abnormal development of their offspring. In addition, reduced sperm motility and impaired germ cells in male zebrafish were also observed, which may be related to the disturbed homeostasis of sex hormones. Notably, the specifically suppressed AR in the brain provides further evidence for the antagonistic effects as above-mentioned. These results confirmed that TBPH affected male reproduction through a classical nuclear receptor-mediated pathway, which would be helpful for assessing the ecological and health risks of TBPH.

Association of glyphosate exposure with multiple adverse outcomes and potential mediators

Glyphosate (GLY) is a widely used herbicide with potential adverse effects on public health. However, the current epidemiological evidence is limited. This study aimed to investigate the potential associations between exposure to GLY and multiple health outcomes. The data on urine GLY concentration and nine health outcomes, including type 2 diabetes mellitus (T2DM), hypertension, cardiovascular disease (CVD), obesity, chronic kidney disease (CKD), hepatic steatosis, cancers, chronic obstructive pulmonary disease (COPD), and neurodegenerative diseases (NGDs), were extracted from NHANES (2013-2016). The associations between GLY exposure and each health outcome were estimated using reverse-scale Cox regression and logistic regression. Furthermore, mediation analysis was conducted to identify potential mediators in the significant associations. The dose-response relationships between GLY exposure with health outcomes and potential mediators were analyzed using restricted cubic spline (RCS) regression. The findings of the study revealed that individuals with higher urinary concentrations of GLY had a higher likelihood of having T2DM, hypertension, CVD and obesity (p < 0.001, p = 0.005, p < 0.001 and p = 0.005, respectively). In the reverse-scale Cox regression, a notable association was solely discerned between exposure to GLY and the risk of T2DM (adjusted HR = 1.22, 95% CI: 1.10, 1.36). Consistent outcomes were also obtained via logistic regression analysis, wherein the adjusted OR and 95% CI for T2DM were determined to be 1.30 (1.12, 1.52). Moreover, the present investigation identified serum high-density lipoprotein cholesterol (HDL) as a mediator in this association, with a mediating effect of 7.14% (p = 0.040). This mediating effect was further substantiated by RCS regression, wherein significant dose-response associations were observed between GLY exposure and an increased risk of T2DM (p = 0.002) and reduced levels of HDL (p = 0.001). Collectively, these findings imply an association between GLY exposure and an increased risk of T2DM in the general adult population.

4-Phenylbutyric acid may prevent mouse ovarian and uterine damage due to procymidone-induced alteration of circRNA Scar and circZc3h4 levels by controlling excessive unfolded protein response

Procymidone (PCM) below the no-observed-adverse-effect-level (NOAEL) has previously been proven to induce ovarian and uterine damage in adolescent mice due to its raised circRNA Scar, decreased circZc3h4, and overactivated unfolded protein response (UPR). Also, 4-phenylbutyric acid (4-PBA) inhibits histone deacetylase and endoplasmic reticulum stress, reduces UPR, improves metabolism, and ensures homeostasis within the endoplasmic reticulum. In this study, 20, 40 and 80 mM of 4-PBA were utilized respectively to intervene the damage caused by 1.0 × 10-5 M PCM to ovaries and uterus in vitro culture. Besides, 100 mg/kg /d 4-PBA was intraperitoneally injected to female adolescent mice before, during and after oral administration of 100 mg/kg /d PCM for prevention and cure to observe tissue changes in the ovaries and uteri, and levels of circRNA Scar, circZc3h4 and UPR members. Our findings demonstrated that in vitro experiments, all doses of 4-PBA could inhibit ovarian and uterine damage caused by PCM, and the effect of 80 mM was especially noticeable. In the in vivo experiments, the best results were obtained when PCM was given with simultaneous 4-PBA intervention, i.e., minimal ovarian and uterine damage. Both in vivo and in vitro, 4-PBA in the ovary and uterus resulted in decreased circRNA Scar levels, increased circZc3h4 abundance, and moderately elevated levels of UPR members. So, it is suggested that 4-PBA moderately activates UPR, partially or completely antagonizing the elevated circRNA Scar and decreased circZc3h4 and consequently preventing PCM-induced ovarian and uterine damage effectively in adolescent mice.

Effects of glyphosate-based herbicides and glyphosate exposure on sex hormones and the reproductive system: From epidemiological evidence to mechanistic insights

Glyphosate-based herbicides (GBHs) containing glyphosate as the active component are extensively used worldwide. Concerns have arisen about their potential risk to human, as glyphosate has been detected in human body fluids. Current controversies surround the endocrine-disrupting properties and transgenerational inheritance of diseases and germline epimutations resulting from exposure to GBHs and glyphosate. This review discusses evidence from in vitro, in vivo, and clinical studies on their impact on sex hormone regulation and reproductive system. Evidence suggests that they act as endocrine-disrupting chemicals, which altering sex hormone levels. Mechanistically, they interfere with hormone signaling pathways by disrupting proteins involved in hormone transport and metabolism. Pathological changes have been observed in male and female reproductive systems, potentially leading to reproductive toxicity. Prenatal exposure may lead to transgenerational inheritance of pathologies and sperm epimutations. However, due to the complexity of glyphosate formulations containing adjuvants identifying higher risk components in environmental exposure becomes challenging.

High doses of GrassOut Max poses reproductive hazard by affecting male reproductive function and early embryogenesis in Swiss albino mice

Clethodim is a widely used and approved class II herbicide, with little information about its impact on the reproductive system. Herein, we investigated the male reproductive toxicity of clethodim using a mouse model. GrassOut Max (26% clethodim-equivalent) or 50 mg kg^-1 body weight analytical grade clethodim (≥90%) were given orally to male mice for 10 d in varying doses. All parameters were assessed at 35 d from the first day of treatment. Significant decrease in testicular weight, decreased germ cell population, elevated DNA damage in testicular cells and lower serum testosterone level was observed post clethodim-equivalent exposure. Epididymal spermatozoa were characterized with significant decrease in motility, elevated DNA damage, abnormal morphology, chromatin immaturity and, decreased acetylated-lysine of sperm proteins. In the testicular cells of clethodim-equivalent treated mice, the expression of Erβ and Gper was significantly higher. Proteomic analysis revealed lower metabolic activity, poor sperm-oocyte binding potential and defective mitochondrial electron transport in spermatozoa of clethodim-equivalent treated mice. Further, fertilizing ability of spermatozoa was compromised and resulted in defective preimplantation embryo development. Together, our data suggest that clethodim exposure risks male reproductive function and early embryogenesis in Swiss albino mice via endocrine disrupting function.

1-Nitropyrene disrupts testicular steroidogenesis via oxidative stress-evoked PERK-eIF2α pathway

Our previous study showed 1-Nitropyrene (1-NP) exposure disrupted testicular testosterone synthesis in mouse, but the exact mechanism needs further investigation. The present research found 4-phenylbutyric acid (4-PBA), an endoplasmic reticulum (ER) stress inhibitor, recovered 1-NP-induced ER stress and testosterone synthases reduction in TM3 cells. GSK2606414, a protein kinase-like ER kinase (PERK) kinase inhibitor, attenuated 1-NP-induced PERK-eukaryotic translation initiation factor 2α (eIF2α) signaling activation and downregulation of steroidogenic proteins in TM3 cells. Both 4-PBA and GSK2606414 attenuated 1-NP-induced steroidogenesis disruption in TM3 cells. Further studies used N-Acetyl-L-cysteine (NAC) as a classical antioxidant to explore whether oxidative stress-activated ER stress mediated 1-NP-induced testosterone synthases reduction and steroidogenesis disruption in TM3 cells and mouse testes. The results showed NAC pretreatment mitigated oxidative stress, and subsequently attenuated ER stress, particularly PERK-eIF2α signaling activation, and downregulation of testosterone synthases in 1-NP-treated TM3 cells. More importantly, NAC extenuated 1-NP-induced testosterone synthesis in vitro and in vivo. The current work indicated that oxidative stress-caused ER stress, particularly PERK-eIF2α pathway activation, mediates 1-NP-downregulated steroidogenic proteins and steroidogenesis disruption in TM3 cells and mouse testes. Significantly, the current study provides a theoretical basis and demonstrates the experimental evidence for the potential application of antioxidant, such as NAC, in public health prevention, particularly in 1-NP-induced endocrine disorder.

Maternal exposure to a glyphosate-based herbicide impairs placental development through endoplasmic reticulum stress in mice

Glyphosate-based herbicides (GBHs) are the most widely used agrochemicals worldwide, increasing the risk of their occurrence in the environment. This study aimed to explore effects and mechanisms of GBH exposure on placental development in vivo during pregnancy in mice. Pregnant mice received GBH by gavage at 0, 5, and 50 mg⋅kg^-1⋅day^-1 doses from gestational day (GD) 1 to GD 13 and were sacrificed on GD 13 or GD19. Our data indicated that GBH administration significantly increased the number of resorbed fetuses, reduced the weight of fetuses and placentas, and inhibited placental growth, as evident from decreased placental total area and spongiotrophoblast area on GD 19. GBH treatment also inhibited proliferation and induced apoptosis of placenta via upregulation of Bax, cleaved caspase-3 and -12 expression, and downregulation of B cell lymphoma (Bcl)-2 expression. Further study showed that GBH exposure significantly increased expression levels of glucose-regulated protein 78 (GRP78), protein kinase RNA-like endoplasmic reticulum kinase (PERK), and C/EBP homologous protein (CHOP) mRNAs and proteins and triggered oxidative stress in placenta on GD 13 and GD 19. In conclusion, our findings suggest that maternal exposure to GBH can impair placental development through the endoplasmic reticulum stress-mediated activation of GRP78/PERK/CHOP signaling pathway in mice.

Disturbance of cellular calcium homeostasis plays a pivotal role in glyphosate-based herbicide-induced oxidative stress

Glyphosate-based herbicides (GBHs) are the most worldwide used pesticides. The wide application of GBHs contaminates the soil and, consequently, water and food resources reaching human consumption. GBHs induce oxidative stress in non-target organisms, leading to a pro-inflammatory and pro-apoptotic cellular status, promoting tissue dysfunction and, thus, metabolic and neurobehavioral changes. This review presents evidence of oxidative damage induced by GBHs and the mechanism of cell damage and health consequences. To summarize, exposure to GBHs may induce disorders in calcium homeostasis related to the activation of ion channels. Also, alterations in pathways related to redox state regulation must have a primordial role in oxidative stress caused by GBHs.

Glyphosate-induced mitochondrial reactive oxygen species overproduction activates parkin-dependent mitophagy to inhibit testosterone synthesis in mouse leydig cells

Glyphosate (GLY), one of the most extensively used herbicides in the world, has been shown to inhibit testosterone synthesis in male animals. Mitochondria are crucial organelles for testosterone synthesis and its dysfunction has been demonstrated to induce the inhibition of testosterone biosynthesis. However, whether low-dose GLY exposure targets mitochondria to inhibit testosterone synthesis and its underlying mechanism remains unclear. Here, an in vitro model of 10 μM GLY-exposed mouse Leydig (TM3) cells was established to elucidate this issue. Data firstly showed that mitochondrial malfunction, mainly manifested by ultrastructure damage, disturbance of mitochondrial dynamics and mitochondrial reactive oxygen species (mtROS) overproduction, was responsible for GLY-decreased protein levels of steroidogenic enzymes, which leads to the inhibition of testosterone synthesis. Enhancement of autophagic flux and activation of mitophagy were shown in GLY-treated TM3 cells, and further studies have revealed that GLY-activated mitophagy is parkin-dependent. Notably, GLY-inhibited testosterone production was significantly improved by parkin knockdown. Finally, data showed that treatment with mitochondria-targeted antioxidant Mito-TEMPO (M-T) markedly reversed GLY-induced mitochondrial network fragmentation, activation of parkin-dependent mitophagy and consultant testosterone reduction. Overall, these findings demonstrate that GLY induces mtROS overproduction to activate parkin-dependent mitophagy, which contributes to the inhibition of testosterone synthesis. This study provides a potential mechanistic explanation for how GLY inhibits testosterone synthesis in mouse Leydig cells.

Geniposide attenuates spermatogenic dysfunction via inhibiting endoplasmic reticulum stress in male mice

BACKGROUND

Spermatogenesis dysfunction is common in clinically infertile patients. Geniposide (GP) is one of the important active ingredients extracted from Eucommia ulmoides. However, the protective effect and mechanism of GP in the treatment of spermatogenic dysfunction is not known yet.

METHODS

After cyclophosphamide-induced spermatogenic dysfunction was established in male mice, we gavaged GP for 4 weeks to evaluate spermatogenic function and anti-apoptotic effects by fertility, testicular weight, sperm quality, endoplasmic reticulum stress (ER stress), comet assay and serum testosterone level.

RESULTS

GP can improve the damage of fertility and reproductive organs induced by cyclophosphamide and increase the number and activity of sperm. In comet assay, it was found that GP administration could alleviate sperm DNA damage induced by cyclophosphamide. In addition, GP treatment can significantly reduce ThT fluorescence intensity and improve endoplasmic reticulum stress induced by cyclophosphamide. Besides, TUNEL staining and WB showed that GP could inhibit the excessive apoptosis of cells and protect testis. (p < 0.05, p < 0.01, p < 0.001).

CONCLUSION

The protective effect of Geniposide on cyclophosphamide-induced spermatogenic dysfunction in mice is related to the inhibition of endoplasmic reticulum stress.

Melatonin ameliorates renal dysfunction in glyphosate- and hard water-treated mice

Chronic interstitial nephritis in agricultural communities (CINAC) is a severe and widespread disease that has been associated with environmental and occupational exposure to glyphosate and hard water. However, the potential underlying mechanisms remain incompletely understood. Melatonin is reported to exert protective effects on the kidney, but whether melatonin can attenuate renal tubular injury in mice exposed to glyphosate combined with hard water is unclear. Here, mice were treated with high doses and environmentally relevant doses of glyphosate (100 mg/kg·bw and 0.7 mg/L, respectively) and/or hard water (2500 mg/L CaCO₃ and 250 mg/L Ca²⁺, respectively) via their drinking water for 12 weeks. We found that high-dose glyphosate or hard water treatment significantly increased the levels of biomarkers of renal damage, including β₂-microglobulin, neutrophil gelatinase-associated lipid carrier protein, and/or albumin, in the urine; these increased biomarker levels were correlated with obvious morphological changes, and all of these changes were also observed in animals exposed to environmentally relevant doses of glyphosate and/or high Ca²⁺ water. Melatonin (10 mg/kg·bw, intraperitoneal injection, daily for 12 weeks) administered concomitantly with high doses of glyphosate and hard water inhibited the glyphosate- and hard water-induced increases in the levels of kidney injury biomarkers and changes in morphology; this result was intriguing. Additionally, glyphosate combined with hard water at both high and environmentally relevant doses significantly upregulated the expression of the endoplasmic reticulum (ER) stress marker proteins Bip, ATF6, and PERK as well as the pyroptosis-related proteins (NLRP3 and caspase 1 signaling proteins) in renal tissues. Similarly, melatonin significantly attenuated the increased ER stress and pyroptosis induced by high doses of glyphosate and hard water. In summary, we conclude that exposure to glyphosate and hard water at both high doses and environmentally relevant doses causes renal dysfunction in mice, and this dysfunction can be attenuated by melatonin, possibly through the inhibition of ER stress and pyroptosis. Our results support the notion that melatonin may have therapeutic potential for the treatment of chronic kidney diseases.

Glyphosate exposure deteriorates oocyte meiotic maturation via induction of organelle dysfunctions in pigs

Background

Recently, defects in mammalian oocytes maturation induced by environmental pollution results in the decreasing animal reproduction. Animal exposed to glyphosate is largely unavoidable because glyphosate is one of the most widely used herbicide worldwide due to its high-efficiency and broad-spectrum effects, which causes glyphosate an environmental contaminant found in soil, water and food. During the last few years, the growing and wider use of glyphosate has raised great concerns about its effects of reproductive toxicity. In this study, using porcine models, we investigated effects of glyphosate on organelle functions during oocyte meiosis.

Results

The results showed glyphosate exposure disrupted porcine oocyte maturation. Expression levels of cumulus expansion-related genes were interfered, further indicating the meiotic defects. The damaging effects were mediated by destruction of mitochondrial distribution and functions, which induced ROS accumulation and oxidative stress, also indicated by the decreased mRNA expression of related antioxidant enzyme genes. We also found an interference of endoplasmic reticulum (ER) distribution, disturbance of Ca²⁺ homeostasis, as well as fluctuation of ER stress, showing with the reduced ER stress-related mRNA or protein expression, which could indicate the dysfunction of ER for protein processing and signal transduction in glyphosate-exposed oocytes. Moreover, glyphosate exposure induced the disruption of lysosome function for autophagy, showing with the decrease of LAMP2 expression and autophagy-related genes mRNA expression. Additionally, our data showed the distribution of Golgi apparatus and the functions of ribosome were disturbed after glyphosate exposure, which might affect protein synthesis and transport.

Conclusions

Collectively, our study showed that exposed to glyphosate could affect animal reproduction by compromising the quality of oocytes through its wide toxic effects on organelle functions.

Endocrine-Disrupting Chemicals and Their Adverse Effects on the Endoplasmic Reticulum

There is growing concern regarding the health and safety issues of endocrine-disrupting chemicals (EDCs). Long-term exposure to EDCs has serious adverse health effects through both hormone-direct and hormone-indirect ways. Accordingly, some EDCs can be a pathogen and an inducer to the susceptibility of disease, even if they have a very low affinity on the estrogen receptor, or no estrogenic effect. Endoplasmic reticulum (ER) stress recently attracted attention in this research area. Because ER and ER stress could be key regulators of the EDC’s adverse effects, such as the malfunction of the organ, as well as the death, apoptosis, and proliferation of a cell. In this review, we focused on finding evidence which shows that EDCs could be a trigger for ER stress and provide specific examples of EDCs, which are known to cause ER stress currently.

Review: Mechanisms of Glyphosate and Glyphosate-Based Herbicides Action in Female and Male Fertility in Humans and Animal Models

Glyphosate (G), also known as N-(phosphonomethyl)glycine is the declared active ingredient of glyphosate-based herbicides (GBHs) such as Roundup largely used in conventional agriculture. It is always used mixed with formulants. G acts in particular on the shikimate pathway, which exists in bacteria, for aromatic amino acids synthesis, but this pathway does not exist in vertebrates. In recent decades, researchers have shown by using various animal models that GBHs are endocrine disruptors that might alter reproductive functions. Our review describes the effects of exposure to G or GBHs on the hypothalamic-pituitary-gonadal (HPG) axis in males and females in terms of endocrine disruption, cell viability, and proliferation. Most of the main regulators of the reproductive axis (GPR54, GnRH, LH, FSH, estradiol, testosterone) are altered at all levels of the HPG axis (hypothalamus, pituitary, ovaries, testis, placenta, uterus) by exposure to GBHs which are considered more toxic than G alone due to the presence of formulants such as polyoxyethylene tallow amine (POEA)." In addition, we report intergenerational impacts of exposure to G or GBHs and, finally, we discuss different strategies to reduce the negative effects of GBHs on fertility.

Glyphosate exposure attenuates testosterone synthesis via NR1D1 inhibition of StAR expression in mouse Leydig cells

Glyphosate is a broad-spectrum herbicide that impairs testosterone synthesis in mammals. Leydig cells (LCs), the primary producers of testosterone, demonstrate rhythmic expression of circadian clock genes both in vivo and in vitro. The nuclear receptor NR1D1 is an important clock component that constitutes the subsidiary transcriptional/translational loop in the circadian clock system. Nr1d1 deficiency resulted in diminished fertility in both male and female mice. However, whether NR1D1 is involved in the glyphosate-mediated inhibition of testosterone synthesis in LCs remains unclear. Here, the involvement of NR1D1 in glyphosate-mediated inhibition of testosterone synthesis was investigated both in vitro and in vivo. Glyphosate exposure of TM3 cells significantly increased Nr1d1 mRNA levels, but decreased Bmal1, Per2, StAR, Cyp11a1, and Cyp17a1 mRNA levels. Western blotting confirmed elevated NR1D1 and reduced StAR protein levels following glyphosate exposure. Glyphosate exposure also reduced testosterone production in TM3 cells. In primary LCs, glyphosate exposure also upregulated Nr1d1 mRNA levels and downregulated the mRNA levels of other clock genes (Bmal1 and Per2) and steroidogenic genes (StAR, Cyp17a1, Cyp11a1, and Hsd3b2), and inhibited testosterone synthesis. Moreover, glyphosate exposure significantly reduced the amplitude and shortened the period of PER2::LUCIFERASE oscillations in primary LCs isolated from mPer2Luciferase knock-in mice. Four weeks of oral glyphosate upregulated NR1D1 at both the mRNA and protein levels in mouse testes, and this was accompanied by a reduction in StAR expression. Notably, serum testosterone levels were also drastically reduced in mice treated with glyphosate. Moreover, dual-luciferase reporter and EMSA assays revealed that in TM3 cells NR1D1 inhibits the expression of StAR by binding to a canonical RORE element present within its promoter. Together, these data demonstrate that glyphosate perturbs testosterone synthesis via NR1D1 mediated inhibition of StAR expression in mouse LCs. These findings extend our understanding of how glyphosate impairs male fertility.

Microcystin-LR inhibits testosterone synthesis via reactive oxygen species-mediated GCN2/eIF2α pathway in mouse testes

Previous studies demonstrated that microcystin-leucine-arginine (MC-LR) disrupted testosterone (T) synthesis, but the underlying mechanisms are not entirely elucidated. This study aims to explore the role of reactive oxygen species (ROS)-mediated GCN2/eIF2α activation on MC-LR-induced disruption of testicular T synthesis. Male mice were intraperitoneally injected with MC-LR (0 or 20 μg/kg) daily for 5 weeks. Serum T was decreased in MC-LR-exposed mice (0.626 ± 0.122 vs 24.565 ± 8.486 ng/ml, P < 0.01), so did testicular T (0.667 ± 0.15 vs 8.317 ± 1.387 ng/mg protein, P < 0.01). Steroidogenic proteins including StAR, CYP11A1 and CYP17A1 were downregulated in MC-LR-exposed mouse testes and TM3 cells. Mechanistically, p-GCN2 and p-eIF2α were elevated in MC-LR-exposed TM3 cells. GCN2iB attenuated MC-LR-induced GCN2 and eIF2α phosphorylation in TM3 cells. Moreover, GCN2iB attenuated MC-LR-induced downregulation of steroidogenic proteins in TM3 cells. Further analysis found that cellular ROS were elevated and HO-1 was upregulated in MC-LR-exposed TM3 cells. PBN rescued MC-LR-induced activation of GCN2/eIF2α signaling in TM3 cells. Additionally, pretreatment with PBN attenuated MC-LR induced downregulation of steroidogenic proteins and synthases in TM3 cells. These results suggest that ROS-mediated GCN2/eIF2α activation contributes partially to MC-LR-caused downregulation of steroidogenic proteins and synthases. The present study provides a new clue for understanding the mechanism of MC-LR-induced endocrine disruption.

Zearalenone perturbs the circadian clock and inhibits testosterone synthesis in mouse Leydig cells

Zearalenone (ZEA), a mycotoxin, is known to impair reproductive capability by disrupting the synthesis and secretion of testosterone by Leydig cells (LCs), although the mechanism is unknown. Robust rhythmicity of circadian clock and steroidogenic genes were identified in LCs. The aim of this study was to examine whether ZEA significantly attenuated the transcription of core clock genes (Bmal1, Dbp, Per2, and Nr1d1) as well as steroidogenic genes (StAR, Hsd3b2, and Cyp11a1) in mouse testis Leydig cell line (TM3). Western blotting confirmed declines in BMAL1, NR1D1, and StAR protein levels. ZEA also suppressed secreted testosterone levels. In primary LCs, isolated from PER2::LUCIFERASE reporter gene knock in mice, ZEA diminished the amplitude of PER2::LUC expression, and induced a phase shift and period extension. In primary LCs, ZEA also suppressed the expression levels of core clock and steroidogenic genes, reduced protein levels of BMAL1, and decreased testosterone secretion. In vivo expression of core clock and steroidogenic genes were reduced in testes of mice exposed to ZEA for 1 week leading to decreased serum testosterone levels. In summary, data suggest that ZEA may impair testosterone synthesis through attenuation of the circadian clock in LCs culminating in reproductive dysfunction in male mammals .

Environment permissible concentrations of glyphosate in drinking water can influence the fate of neural stem cells from the subventricular zone of the postnatal mouse

The developing nervous system is highly vulnerable to environmental toxicants especially pesticides. Glyphosate pesticide induces neurotoxicity both in humans and rodents, but so far only when exposed to higher concentrations. A few studies, however, have also reported the risk of general toxicity of glyphosate at concentrations comparable to allowable limits set up by environmental protection authorities. In vitro data regarding glyphosate neurotoxicity at concentrations comparable to maximum permissible concentrations in drinking water is lacking. In the present study, we established an in vitro assay based upon neural stem cells (NSCs) from the subventricular zone of the postnatal mouse to decipher the effects of two maximum permissible concentrations of glyphosate in drinking water on the basic neurogenesis processes. Our results demonstrated that maximum permissible concentrations of glyphosate recognized by environmental protection authorities significantly reduced the cell migration and differentiation of NSCs as demonstrated by the downregulation of the expression levels of the neuronal ß-tubulin III and the astrocytic S100B genes. The expression of the cytoprotective gene CYP1A1 was downregulated whilst the expression of oxidative stresses indicator gene SOD1 was upregulated. The concentration comparable to non-toxic human plasma concentration significantly induced cytotoxicity and activated Ca2+ signalling in the differentiated culture. Our findings demonstrated that the permissible concentrations of glyphosate in drinking water recognized by environmental protection authorities are capable of inducing neurotoxicity in the developing nervous system.

Perfluorooctane sulfonate (PFOS) disrupts testosterone biosynthesis via CREB/CRTC2/StAR signaling pathway in Leydig cells

Perfluorooctane sulfonate (PFOS), a stable end-product of perfluorinated compounds (PFCs), is associated with male reproductive disorders, but its underlying mechanisms are still unclear. We used in vivo and in vitro models to investigate the effects of PFOS on testosterone biosynthesis and related mechanisms. First, male ICR mice were orally administered PFOS (0-10 mg/kg/bw) for 4 weeks. Bodyweight, sperm count, reproductive hormones, mRNA expression of the genes related to testosterone biosynthesis, and the protein expression of protein kinase A (PKA), p38 mitogen-activated protein kinase (MAPK), cAMP-response element binding protein (CREB), CREB regulated transcription coactivator 2 (CRTC2) and steroidogenic acute regulatory protein (StAR) were evaluated. Furthermore, mouse primary Leydig cells were used to delineate the molecular mechanisms that mediate the effects of PFOS on testosterone biosynthesis. Our results demonstrated that PFOS dose-dependently decreased sperm count, testosterone level, CRTC2/StAR expression, and damaged testicular interstitium morphology, paralleled by increase in phosphorylated PKA, CREB and p38 in testes. Additionally, similar to the in vivo results, PFOS significantly decreased testosterone secretion, CRTC2/StAR expression, interaction between CREB and CRTC2 and binding of CREB/CRTC2 to StAR promoter region, paralleled by increase in phosphorylated-p38, PKA, and CREB expression. Meanwhile, inhibition of p38 by SB203580, or inhibition of PKA by H89 can significantly alleviate the above PFOS-induced effects. As such, the present study highlights a role of the CREB/CRTC2/StAR signaling pathway in PFOS-induced suppression of testosterone biosynthesis, advancing our understanding of molecular mechanisms for PFOS-induced male reproductive disorders.

Assessing Agricultural Toxicity in Brazil: Advances and Opportunities in the 21st Century

Agriculture in the 21st century faces multiple challenges to produce food for the growing population using ethical/sustainable and efficient methods safely for humans and the environment. Brazil today is a world leader in terms of production of food of plant origin, both for human consumption and animal feed. Agriculture and livestock raising are critical economic activities in maintaining a positive balance in its economy. As a consequence, the registration and use of pesticides in Brazil have grown at an accelerated rate. This work shows the current situation in Brazil in terms of the prevailing laws about the registration of pesticides, with a focus on the toxicological aspects related to human health. The regulatory aspects of registration of pesticides in Brazil, the mandatory testing for evaluating pesticide toxicity, adoption of the Globally Harmonized System of Classification and Labeling of Chemicals, and recent progress toward nonanimal methods to toxicity evaluation were explored in this work. In this field, Brazil has advanced and there are opportunities and challenges. There is still much to be done and investments to be made so that Brazil can definitively consolidate its conduct within the context of a Modern Regulatory Toxicology, which has entered the 21st century.