Zearalenone exposure impairs ovarian primordial follicle formation via down-regulation of Lhx8 expression in vitro

Cyanidin-3-O-glucoside Mitigates the Ovarian Defect Induced by Zearalenone via p53-GADD45a Signaling during Primordial Follicle Assembly

Zearalenone (ZEN) is well known as a kind of endocrine disruptor whose exposure is capable of causing reproductive toxicity in animals. Cyanidin-3-O-glucoside (C3G) is a derivative of cyanidin and owns multiple biofunctions, and prior efforts have suggested that C3G has therapeutic actions for reproductive diseases. In this article, a ZEN exposure model during primordial follicle assembly was constructed using the in vitro culture platform of neonatal mouse ovaries. We investigated the protective effect of C3G on ZEN-induced ovarian toxicity during primordial follicle assembly in mice, as well as its potential mechanism. Interestingly, we observed that C3G could effectively protect the ovary from ZEN damage, mainly by restoring primordial follicle assembly, which upregulated the expression of LHX8 and SOHLH1 proteins and relieved ZEN-induced DNA damage. Next, to explore the mechanism by which C3G rescued ZEN-induced injury, we performed RNA sequencing (RNA-seq). The bioinformatic analysis illustrated that the rescue pathway of C3G was associated with p53-Gadd45a signaling and cell cycle. Then, western blotting and flow cytometry results revealed that C3G restored the expression levels of cyclin-dependent kinase 6 (CDK6) and cyclin D2 (CCND2) and regulated the ovarian cell cycle to normal. In conclusion, our findings manifested that C3G could alleviate ZEN-induced primordial follicle assembly impairment by restoring the cell cycle involved in p53-GADD45a signaling.

Low dose of zearalenone inhibited the proliferation of porcine prospermatogonia and transformed the physiology through cytokine-cytokine receptor interaction

Zearalenone (ZEA) is a prevalent mycotoxin functions as an endocrine disrupter to the reproductive systems of farm animals, especially in pigs. To evaluate the effect and the underlying molecular changes that occurred when the porcine germline stem cells were exposed to ZEA, prospermatogonia (ProSGs) were enriched and treated with a gradient concentration (0-10 μM) of ZEA for 2-8 days. Our results showed that the ZEA treatment inhibited the proliferation of ProSGs in a dose-dependent manner with a critical concentration at 1 μM. Transcriptome analysis revealed that the differentially expressed genes mainly concentrated on the molecular function of positive regulation of response to stimulus, and the most enriching pathway is cytokine-cytokine receptor interaction. ZEA exposure decreased a buck of cytokine/chemokine expression involved in the inflammatory response and stem cells maintenance/self-renewal, moreover, some energy expenditure and anti-apoptosis genes were also down-regulated, while the up-regulated genes were mainly connected with the innate immunity. These data demonstrate that ZEA induces multiply cellular damage and may eventually do harm to the health and fertility of animals.

Role of epigenetics in mycotoxin toxicity: a review

Mycotoxins can induce cell cycle disorders, cell proliferation, oxidative stress, and apoptosis through pathways such as those associated with MAPK, JAK2/STAT3, and Bcl-w/caspase-3, and cause reproductive toxicity, immunotoxicity, and genotoxicity. Previous studies have explored the toxicity mechanism of mycotoxins from the levels of DNA, RNA, and proteins, and proved that mycotoxins have epigenetic toxicity. To explore the toxic effects and mechanisms of these changes in mycotoxins, this paper summarizes the changes in DNA methylation, non-coding RNA, RNA and histone modification induced by several common mycotoxins (zearalenone, aflatoxin B1, ochratoxin A, deoxynivalenol, T-2 toxin, etc.) based on epigenetic studies. In addition, the roles of mycotoxin-induced epigenetic toxicity in germ cell maturation, embryonic development, and carcinogenesis are highlighted. In summary, this review provides theoretical support for a better understanding of the regulatory mechanism of mycotoxin epigenotoxicity and the diagnosis and treatment of diseases.

Zearalenone induces mitochondria-associated endoplasmic reticulum membranes dysfunction in piglet Sertoli cells based on endoplasmic reticulum stress

Zearalenone (ZEA) is an estrogen-like mycotoxin, which mainly led to reproductive toxicity. The study aimed to investigate the molecular mechanism of ZEA-induced dysfunction of mitochondria-associated endoplasmic reticulum membranes (MAM) in piglet Sertoli cells (SCs) via the endoplasmic reticulum stress (ERS) pathway. In this study, SCs were used as a research object that was exposed to ZEA, and ERS inhibitor 4-Phenylbutyrate acid (4-PBA) was used as a reference. The results showed that ZEA damaged cell viability and increased Ca²⁺ levels; damaged the structure of MAM; up-regulated the relative mRNA and protein expression of glucose-regulated protein 75 (Grp75) and mitochondrial Rho-GTPase 1 (Miro1), while inositol 1,4,5-trisphosphate receptor (IP3R), voltage-dependent anion channel 1 (VDAC1), mitofusin2 (Mfn2) and phosphofurin acidic cluster protein 2 (PACS2) were down-regulated. After a 3 h 4-PBA-pretreatment, ZEA was added for mixed culture. The results of 4-PBA pretreatment showed that inhibition of ERS reduced the cytotoxicity of ZEA against piglet SCs. Compared with the ZEA group, inhibition of ERS increased cell viability and decreased Ca²⁺ levels; restored the structural damage of MAM; down-regulated the relative mRNA and protein expression of Grp75 and Miro1; and up-regulated the relative mRNA and protein expression of IP3R, VDAC1, Mfn2, and PACS2. In conclusion, ZEA can induce MAM dysfunction in piglet SCs via the ERS pathway, whereas ER can regulate mitochondria through MAM.

Maternal Zearalenone Exposure Affects Gut Microbiota and Follicular Development in Suckled Offspring

Zearalenone (ZEN) is a mycotoxin that is widely present in feed and agricultural products. Studies have demonstrated that ZEN, as a type of estrogen analogue, can significantly affect the female reproductive system. Breast milk is the best nutrient for infant growth and development, but it is still unknown whether ZEN influences the fertility of offspring through suckling. In this study, we collected fecal and ovarian tissue from neonatal female offspring, whose mothers were exposed to ZEN for 21 days, and explored the effects of maternal ZEN exposure on intestinal microecology and follicular development in the mouse using 16S rRNA amplicon sequencing technology. Our findings suggested that maternal ZEN exposure significantly diminished ovarian reserve, increased apoptosis of ovarian granulosa cell (GC), and impacted the developmental competence of oocytes in lactating offspring. In addition, the results of 16S rRNA sequencing showed that the abundance of gut microbiota in offspring was significantly changed, including Bacteroidetes, Proteobacteria, and Firmicutes. This leads to alterations of glutathione metabolism and the expression of antioxidant enzymes in ovaries. In summary, our findings supported a potential relationship between gut microbiota and abnormal ovarian development caused by ZEN, which offers novel insights for therapeutic strategies for reproductive disorders induced by ZEN exposure.

Hippo Signaling in the Ovary: Emerging Roles in Development, Fertility, and Disease

Emerging studies indicate that the Hippo pathway, a highly conserved pathway that regulates organ size control, plays an important role in governing ovarian physiology, fertility, and pathology. Specific to the ovary, the spatiotemporal expression of the major components of the Hippo signaling cascade are observed throughout the reproductive lifespan. Observations from multiple species begin to elucidate the functional diversity and molecular mechanisms of Hippo signaling in the ovary in addition to the identification of interactions with other signaling pathways and responses to various external stimuli. Hippo pathway components play important roles in follicle growth and activation, as well as steroidogenesis, by regulating several key biological processes through mechanisms of cell proliferation, migration, differentiation, and cell fate determination. Given the importance of these processes, dysregulation of the Hippo pathway contributes to loss of follicular homeostasis and reproductive disorders such as polycystic ovary syndrome (PCOS), premature ovarian insufficiency, and ovarian cancers. This review highlights what is currently known about the Hippo pathway core components in ovarian physiology, including ovarian development, follicle development, and oocyte maturation, while identifying areas for future research to better understand Hippo signaling as a multifunctional pathway in reproductive health and biology.

Recent Research on Fusarium Mycotoxins in Maize—A Review

Maize (Zea mays L.) is one of the most susceptible crops to pathogenic fungal infections, and in particular to the Fusarium species. Secondary metabolites of Fusarium spp.—mycotoxins are not only phytotoxic, but also harmful to humans and animals. They can cause acute or chronic diseases with various toxic effects. The European Union member states apply standards and legal regulations on the permissible levels of mycotoxins in food and feed. This review summarises the most recent knowledge on the occurrence of toxic secondary metabolites of Fusarium in maize, taking into account modified forms of mycotoxins, the progress in research related to the health effects of consuming food or feed contaminated with mycotoxins, and also the development of biological methods for limiting and/or eliminating the presence of the same in the food chain and in compound feed.

Mycotoxin surveillance on wheats in Shandong province, China, reveals non-negligible probabilistic health risk of chronic gastrointestinal diseases posed by deoxynivalenol

Abnormal climate changes have resulted in over-precipitation in many regions. The occurrence and contamination levels of mycotoxins in crops and cereals have been elevated largely. From 2017 to 2019, we did investigation targeting 15 mycotoxins shown in the wheat samples collected from Shandong, a region suffering over-precipitation in China. We found that deoxynivalenol (DON) was the dominant mycotoxin contaminating wheats, with detection rates 304/340 in 2017 (89.41%), 303/330 in 2018 (91.82%), and 303/340 in 2019 (89.12%). The ranges of DON levels were < 4 to 580 μg/kg in 2017, < 4 to 3070 μg/kg in 2018, and < 4 to 1540 μg/kg in 2019. The exposure levels were highly correlated with local precipitation. Male exposure levels were generally higher than female's, with significant difference found in 2017 (1.89-fold, p = 0.023). Rural exposure levels were higher than that of cities but not statistically significant (1.41-fold, p = 0.13). Estimated daily intake (EDI) and margin of exposure (MoE) approaches revealed that 8 prefecture cities have probabilistically extra adverse health effects (vomiting or diarrhea) cases > 100 patients in 100,000 residents attributable to DON exposure. As a prominent wheat-growing area, Dezhou city reached ~ 300/100,000 extra cases while being considered as a major regional contributor to DON contamination. Our study suggests that more effort should be given to the prevention and control of DON contamination in major wheat-growing areas, particularly during heavy precipitation year. The mechanistic association between DON and chronic intestinal disorder/diseases should be further investigated.

Oxidative stress as a plausible mechanism for zearalenone to induce genome toxicity

Zearalenone (ZEN), a common non-steroidal estrogenic mycotoxin of the Fusarium genus, is one of the most frequent and powerful contaminant of grains and cereal products representing a serious threat for people and livestock health. In fact, ZEN causes cytotoxicity and genotoxicity in a variety of cell types at least in part through binding to estrogen receptors (ERs). The main pathways through which ZEN induces such effects remain, however, elusive. In particular, how the mycotoxin causes DNA damage, dysregulates DNA repair mechanisms, changes epigenome of targeted cells and, not least, affects chromatin conformation and non-coding RNA (ncRNA), is unclear. In the present paper, following extensive review of the literature about such ZEN effects and our own experience in studying the effects of this compound on reproductive processes, we propose that increased production of reactive oxygen species (ROS) and consequently oxidative stress (OS) are central in ZEN genotoxicity. Besides to shed light on the action mechanisms of the mycotoxin, this notion might help to develop effective strategies to counteract its deleterious biological effects.

Identification of apoptotic pathways in zearalenone-treated mouse sertoli cells

Zearalenone (ZEN), one of the most prevalent non-steroidal oestrogenic mycotoxins, is primarily produced by Fusarium fungi. Due to its toxicity as an oestrogenic compound and wide distribution in feed and foods, the reproductive toxicology of ZEN exposure is of public concern. The aim of the present study was to investigate the effect of ZEN on Sertoli cells to identify apoptotic pathways induced by this compound. We found that ZEN reduced the viability and caused apoptosis in Sertoli cells in vitro. Notably, we observed that such effects were associated with a significant increase in reactive oxygen species (ROS) and the number of cells that showed positive staining for γH2AX and RAD51, enzymes essential for repairing DNA damage. There was a parallel decrease in the expression of occludin and connexin 43, proteins that are present in the testis-blood barrier and gap junctions of Sertoli cells, respectively. Overall, the present study confirms that ZEN exposure can have serious deleterious effects on mammalian Sertoli cells and offers novel insight about its molecular targets in these cells.

Impaired primordial follicle assembly in offspring ovaries from zearalenone-exposed mothers involves reduced mitochondrial activity and altered epigenetics in oocytes

Previous works have shown that zearalenone (ZEA), as an estrogenic pollutant, has adverse effects on mammalian folliculogenesis. In the present study, we found that prolonged exposure of female mice to ZEA around the end of pregnancy caused severe impairment of primordial follicle formation in the ovaries of newborn mice and altered the expression of many genes in oocytes as revealed by single-cell RNA sequencing (scRNA-seq). These changes were associated with morphological and molecular alterations of mitochondria, increased autophagic markers in oocytes, and epigenetic changes in the ovaries of newborn mice from ZEA-exposed mothers. The latter increased expression of HDAC2 deacetylases was leading to decreased levels of H3K9ac and H4K12ac. Most of these modifications were relieved when the expression of  Hdac2 in newborn ovaries was reduced by RNA interference during in vitro culture in the presence of ZEA. Such changes were also alleviated in offspring ovaries from mothers treated with both ZEA and the coenzyme Q10 (CoQ10), which is known to be able to restore mitochondrial activities. We concluded that impaired mitochondrial activities in oocytes caused by ZEA are at the origin of metabolic alterations that modify the expression of genes controlling autophagy and primordial follicle assembly through changes in epigenetic histones.

Intergenerational protein deficiency and adolescent reproductive function of subsequent female generations (F1 and F2) in rat model

Background

Efficient reproductive function is an important characteristic that has evolved through natural selection. Nutrition can modulate reproductive activities at different levels, and its effect on reproduction is deemed complex and less predictable.

Objective

This study aims at investigating the underlying effect of persistent dietary protein deficiency during early life on reproductive parameters of subsequent (F₁ and F₂) generations.

Method

Rats in group of four (4) were fed daily, different ration of protein diet (PD) formulated as: 21% protein diet, 10%protein diet, 5%protein diet and control diet (rat chow, containing 16–18% protein). They were fed ad libitum before mating, throughout gestation and lactation, and next generations were weaned to the maternal diet. Reproductive function analysis (which include; gestation and pubertal hormonal profiling, onset of puberty, oestrus cyclicity, sexual response) and morphometric analysis of the ovarian structure were carried out to assess associated consequences.

Results

There was significant reduction in the fertility index (Control; 85.8%., 21%PD; 88.43%., as compared to 10%PD; 65.9%., 5%PD; 35.78%.,) at F_1, also recurring in F₂ respectively as a consequence of altered reproductive function in the protein deficient models at P ≤ 0.05. Low protein diet posed suboptimal intrauterine condition, which was linked to increased prenatal morbidity and mortality (control; 11.3%., 21%PD; 3.3%., 10%PD; 27.4%., 5%PD; 32.9%), low birthweight (control; 5.29, 4.9 g., 21%PD; 5.5, 5.06 g., 10%PD; 4.05, 3.86 g., 5%PD; 2.7, 2.5 g) at F₁ and F₂ respectively, delayed onset of puberty (with average pubertal age set at: control; PND 36, 21%PD; PND 38 while 10%PD; PND 62., and 5%PD; PND 67), followed by induced cycle irregularity, altered follicular maturation and endocrine dysfunction, more severe in 5%PD.

Conclusion

Reproductive status of a female organism depends on the maintenance of ovarian structure and function that has been associated with the hypothalamic pituitary-gonadal axis, hormonal events and sexual maturity. There is therefore an association between persistent early life protein deficiency and reproductive response which mechanistically involves life-long changes in key ovarian cytoarchitecture and function.

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Intergenerational protein malnutrition exerts female hormonal dysregulation and irregular cyclicity at adolescence.

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It delayed pubertal attainment and reproductive performance that persists to the next–generation of rats.

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Perinatal protein deficiency also altered the ovarian morphology with an implication on fertility index across generations.

Deoxynivalenol and zearalenone: Different mycotoxins with different toxic effects in donkey (Equus asinus) endometrial epithelial cells

Deoxynivalenol (DON) and zearalenone (ZEA), which are commonly found in feed products, exhibit serious negative effects on the reproductive systems of domestic animals. However, the toxicity of mycotoxins on the uterine function of donkey (Equus asinus) remains unclear. This study investigated the biological effects of DON and ZEA exposure on donkey endometrial epithelial cells (EECs). It was administered 10 μM and 30 μM DON and ZEA to cells cultured in vitro. The results showed that 10 μM DON exposure markedly changed the expression levels of pyroptosis-associated genes and that 30 μM ZEA exposure changed the expression levels of inflammation-associated genes in EECs. The mRNA expression of cancer-promoting genes was markedly upregulated in cells exposed to DON and 30 μM ZEA; in particular, 10 μM and 30 μM DON and ZEA markedly disturbed the expression of androgen and estrogen secretion-related genes. Furthermore, Q-PCR, Western blot, and immunofluorescence analyses verified the different expression patterns of related genes in DON- and ZEA-exposed EECs. Collectively, these results illustrated the impact of exposure to different toxins and concrete toxicity on the mRNA expression of EECs from donkey in vitro.

Updated Review of the Toxicity of Selected Fusarium Toxins and Their Modified Forms

Mycotoxins are one of the most dangerous food and feed contaminants, hence they have significant influence on human and animal health. This study reviews the information reported over the last few years on the toxic effects of the most relevant and studied Fusarium toxins and their modified forms. Deoxynivalenol (DON) and its metabolites can induce intracellular oxidative stress, resulting in DNA damage. Recent studies have also revealed the capability of DON and its metabolites to disturb the cell cycle and alter amino acid expression. Several studies have attempted to explore the mechanism of action of T-2 and HT-2 toxins in anorexia induction. Among other findings, two neurotransmitters associated with this process have been identified, namely substance P and serotonin (5-hydroxytryptamine). For zearalenone (ZEN) and its metabolites, the literature points out that, in addition to their generally acknowledged estrogenic and oxidative potentials, they can also modify DNA by altering methylation patterns and histone acetylation. The ability of the compounds to induce alterations in the expression of major metabolic genes suggests that these compounds can contribute to the development of numerous metabolic diseases, including type 2 diabetes.

Maternal Zearalenone exposure impacted ovarian follicle formation and development of suckled offspring

Zearalenone (ZEN) is a secondary metabolite, which is mainly produced by Fusarium fungi and exists in various feeds and agricultural products. Recently, an increasing amount of data has shown that ZEN, as an estrogen-like hormone, can have harmful effects on the female reproductive system, especially on oogenesis and folliculogenesis. Breast milk is considered to be the ideal form of nutrition for infants; however, there are some records of contaminants in food, such as mycotoxins, which may be transferred from maternal blood to milk. In this study, we investigated the toxic effects of breast milk on folliculogenesis in offspring following maternal ZEN exposure. Our results showed that maternal ZEN exposure significantly inhibited the process of primordial follicle (PF) assembly and reduced the number of PFs in suckled offspring's ovaries. In addition, RNA-seq analysis showed that RIG-I-like receptor (RLRs) signaling pathways were activated after exposed to ZEN, which increased the expression levels of DNA damage (γ-H2AX, RAD51, and PARP1) and apoptosis related protein (BAX/BCL2 and Caspase-3). Finally, ZEN exposure interfered with follicular development, as evidenced by the reduced percentages of oocyte maturation and embryonic development when the offspring grew to adolescence. It is worth noting that maternal ZEN exposure disrupted the tri-methylation levels of H3K4, H3K9, and H3K27 in the offspring's oocytes. Our results indicated that maternal ZEN exposure affected ovarian development in offspring through the breast milk, which may be detrimental to their reproductive capability in adult life.

Obesity alters the ovarian proteomic response to zearalenone exposure†

Zearalenone (ZEN), a nonsteroidal estrogenic mycotoxin, is detrimental to female reproduction. Altered chemical biotransformation, depleted primordial follicles and a blunted genotoxicant response have been discovered in obese female ovaries, thus, this study investigated the hypothesis that obesity would enhance ovarian sensitivity to ZEN exposure. Seven-week-old female wild-type nonagouti KK.Cg-a/a mice (lean) and agouti lethal yellow KK.Cg-Ay/J mice (obese) received food and water ad libitum, and either saline or ZEN (40 μg/kg) per os for 15 days. Body and organ weights, and estrous cyclicity were recorded, and ovaries collected posteuthanasia for protein analysis. Body and liver weights were increased (P < 0.05) in the obese mice, but obesity did not affect (P > 0.05) heart, kidney, spleen, uterus, or ovary weight and there was no impact (P > 0.05) of ZEN exposure on body or organ weight in lean or obese mice. Obese mice had shorter proestrus (P < 0.05) and a tendency (P = 0.055) for longer metestrus/diestrus. ZEN exposure in obese mice increased estrus but shortened metestrus/diestrus length. Neither obesity nor ZEN exposure impacted (P > 0.05) circulating progesterone, or ovarian abundance of EPHX1, GSTP1, CYP2E1, ATM, BRCA1, DNMT1, HDAC1, H4K16ac, or H3K9me3. Lean mice exposed to ZEN had a minor increase in γH2AX abundance (P < 0.05). In lean and obese mice, LC-MS/MS identified alterations to proteins involved in chemical metabolism, DNA repair and reproduction. These data identify ZEN-induced adverse ovarian modes of action and suggest that obesity is additive to ZEN-induced ovotoxicity.

Zearalenone Blocks Autophagy Flow and Induces Cell Apoptosis During Embryo Implantation in Gilts

Zearalenone (ZEA) has been proved to be toxic, particularly to the reproductive system of gilts. The effect of ZEA on gilts during embryo implantation window period is of particular interests. Here, we observed window stage dysontogenesis of gilts treated with ZEA. In endometrial tissues and cells, autophagosomes increased significantly and mitochondria were damaged with increasing ZEA concentration. Addition of autophagy inhibitor confirmed that ZEA blocks the autophagic flow in the fusion of autophagosomes and lysosomes. In conclusion, ZEA exposure during embryo implantation results in endometrium inflammation by activating autophagy while blocking autophagy flow at the same time, leading to the significant accumulation of autophagosomes. The aforementioned effects of ZEA induce the apoptosis of primary endometrial cells through the caspase3 pathway, which would break the uterus environment balance and finally lead to embryo implantation failure and dysontogenesis in gilts.

Impact of Fusarium-Derived Mycoestrogens on Female Reproduction: A Systematic Review

Contamination of the world's food supply and animal feed with mycotoxins is a growing concern as global temperatures rise and promote the growth of fungus. Zearalenone (ZEN), an estrogenic mycotoxin produced by Fusarium fungi, is a common contaminant of cereal grains and has also been detected at lower levels in meat, milk, and spices. ZEN's synthetic derivative, zeranol, is used as a growth promoter in United States (US) and Canadian beef production. Experimental research suggests that ZEN and zeranol disrupt the endocrine and reproductive systems, leading to infertility, polycystic ovarian syndrome-like phenotypes, pregnancy loss, and low birth weight. With widespread human dietary exposure and growing experimental evidence of endocrine-disrupting properties, a comprehensive review of the impact of ZEN, zeranol, and their metabolites on the female reproductive system is warranted. The objective of this systematic review was to summarize the in vitro, in vivo, and epidemiological literature and evaluate the potential impact of ZEN, zeranol, and their metabolites (commonly referred to as mycoestrogens) on female reproductive outcomes. We conducted a systematic review (PROSPERO registration CRD42020166469) of the literature (2000-2020) following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The data sources were primary literature published in English obtained from searching PubMed, Web of Science, and Scopus. The ToxR tool was applied to assess risk of bias. In vitro and in vivo studies (n = 104) were identified and, overall, evidence consistently supported adverse effects of mycoestrogens on physiological processes, organs, and tissues associated with female reproduction. In non-pregnant animals, mycoestrogens alter follicular profiles in the ovary, disrupt estrus cycling, and increase myometrium thickness. Furthermore, during pregnancy, mycoestrogen exposure contributes to placental hemorrhage, stillbirth, and impaired fetal growth. No epidemiological studies fitting the inclusion criteria were identified.

Single-cell transcriptomic profiling provides insights into the toxic effects of Zearalenone exposure on primordial follicle assembly

Rationale: Zearalenone (ZEN), a pollutant in our daily diet, seriously threatens the reproductive health of humans and animals. The primordial follicle (PF) assembly in the mouse occurs during the perinatal period, which determines the whole ovarian reserve in reproductive lifespan. In the current investigation, we administered ZEN orally to perinatal mice from 16.5 days post coitum (dpc) to postnatal day 3 (PD3), and single-cell RNA sequencing (scRNA-seq) was performed on PD0 and PD3 ovarian tissues in the offspring to check ZEN toxic to primordial follicle formation at the single cell level. Methods: Ovarian tissues (in vivo) were examined by single cell RNA sequencing analysis, Immunostaining, and Western blotting. Ovarian tissues (in vitro) were examined by qRT-PCR, Immunostaining, and Western blotting. Results: We found that ZEN exposure altered the developmental trajectory of both germ cells and granulosa cells. Furthermore, after establishing the cell-cell communication network between germ cells and granulosa cells, we found that this was perturbed by ZEN exposure, especially during the Hippo signaling pathway. Conclusions: This study showed that ZEN affected the status of germ cells and granulosa cells through the Hippo signaling pathway and blocked the assembly of PFs. This research contributes to our deeper understanding of the mechanisms of toxicity in different cell types and the disruption of normal intercellular signaling by ZEN exposure.

Responses of oxidative stress and inflammatory cytokines after zearalenone exposure in human kidney cells

Zearalenone is a mycotoxin widely found worldwide that is produced by several fungal species. Due to its similarity to estradiol, it has been shown to have toxic effects on the reproductive system. Although various animal studies have been conducted to investigate the toxic effects of zearalenone, the mechanisms of toxicity have not been fully elucidated. The aim of the study was to investigate the dose-dependent toxic effects of zearalenone exposure in human kidney cells. The half-maximal inhibitory concentration values of zearalenone in HK-2 cells were found to be 133.42 and 101.74 µM in MTT- and NRU-tests, respectively. Zearalenone exposure at concentrations of 1, 10 and 50 µM decreased cell proliferation by 2.1, 11.07 and 24.34%, respectively. Reactive oxygen species levels increased significantly in a dose-dependent manner. A significant increase was observed in the expressions of MGMT, α-GST, Hsp70 and HO-1 genes, which are associated with oxidative damage, while a significant decrease in L-Fabp gene expression was observed. Moreover, zearalenone increased gene expression of inflammatory cytokines, such as IL-6, IL-8, TNFα and MAPK8. Significant increases were observed at the level of global DNA methylation and expression of DNMT1 in all exposure groups. These results indicate that changes in DNA methylation and oxidative damage may play an important role in the toxicity of zearalenone.

Zearalenone exposure triggered porcine granulosa cells apoptosis via microRNAs-mediated focal adhesion pathway

Zearalenone (ZEA), a metabolite of Fusarium, which is commonly found in moldy feed crops, is a well-known exogenous endocrine disruptor and has serious negative effects on animal reproduction. In order to understand the toxic effects of ZEA exposure on porcine granulosa cells (pGCs), which were exposed to 10 μM and 30 μM ZEA for 48 h in vitro, several methods were used for analysis. Flow cytometry and TUNEL analysis showed that the apoptosis of pGCs significantly increased in a dose-dependent manner after ZEA exposure compared with that of the control group. Whole transcriptome RNA-seq analysis was performed to reveal the mRNAs and miRNAs expression changes of pGCs after ZEA exposure and it was found that the expression of apoptosis-related genes was altered after ZEA exposure, and miRNAs were also significantly different among the experimental groups. In particular, ZEA exposure affected the expression of miRNAs associated with apoptosis-related pathways, such as miR-744, miR-1343 and miR-331-3p, as well as focal adhesion pathways related genes, Pak4 and Elk1, which were also involved in the apoptosis-related pathways. Moreover, the regulation networks between apoptosis-related mRNA and miRNAs were confirmed with the results of RT-qPCR and immunofluorescence. In conclusion, our results here demonstrated that ZEA exposure impaired pGCs growth and apoptosis via miRNAs-mediated focal adhesion pathway.

Chlorogenic acid rescues zearalenone induced injury to mouse ovarian granulosa cells

Zearalenone (ZEA), a toxic substance produced by Fusarium fungi, accumulated in cereals grain and animal feed, causes injury to humans and animals. ZEA can induce obvious reproductive toxicity with the ovarian granulosa cells (GCs) as the main target. However, the study on exploring the protective compounds against ZEA-induced mouse primary ovarian GCs damage remains less. In the current study, the protective effect of 20 compounds derived from traditional Chinese medicines (TCMs) on the injury of mouse GCs caused by ZEA were evaluated using MTT assay and the cell morphology. Our results showed that chlorogenic acid (250, 500, and 1000 μg/mL) significantly suppress ZEA-induced GCs death. Western blot analysis suggested chlorogenic acid could rescue the up-regulated apoptosis of GCs induced by ZEA via attenuating the protein expression of cleaved caspase-3, the ratio of Bax/Bcl-2 and cleaved-PARP. Our results provide strong evidence that chlorogenic acid warrants further optimization for more potent and safer compounds for against the ZEA lead toxicity to humans and animals.

Zearalenone-induced aberration in the composition of the gut microbiome and function impacts the ovary reserve

Zearalenone (ZEA), as a contaminant commonly found in our daily diet, has been widely studied for its toxicity. However, the exact mechanism underlying ZEA induced reproduction disorders remains unclear. Our study aimed to elucidate the underlying relationship between aberrations in the gut microbiota and the degeneration of the ovarian reserve following exposure to ZEA. Four-week-old mice were treated with different doses (0, 20, 40 μg/kg bw/day) of ZEA for 2 weeks and it was found that the primordial follicles were dramatically decreased when compared to untreated controls. Moreover, we applied metagenomic shotgun sequencing to investigate the effects of ZEA exposure on the population composition and function of gut microbiota. The results showed that the abundance of three susceptible bacterial strains, parabacteroides, bacteroides and lachnospiraceae were increased in a dose-dependent manner after ZEA exposure, whereas the bacterial glycerophospholipid metabolism pathway was greatly suppressed. Of note, utilizing LC/MS we found lysophosphatidylcholines (LPCs), important metabolites in the process of glycerophospholipid metabolism, were markedly decreased in the plasma of the ZEA treated mice. In conclusion, our findings here provide evidences that the dysfunction in gut microbiome after ZEA exposure may affect the ovarian reserve.

Evaluation of the epigenetic alterations and gene expression levels of HepG2 cells exposed to zearalenone and α-zearalenol

Zearalenone, produced by various Fusarium species, is a non-steroidal estrogenic mycotoxin that contaminates cereals, resulting in adverse effects on human health. We investigated the effects of zearalenone and its metabolite alpha zearalenol on epigenetic modifications and its relationship with metabolic pathways in human hepatocellular carcinoma cells following 24 h of exposure. Zearalenone and alpha zearalenol at the concentrations of 1, 10 and 50 μM significantly increased global levels of DNA methylation and global histone modifications (H3K27me3, H3K9me3, H3K9ac). Expression levels of the chromatin modifying enzymes EHMT2, ESCO1, HAT1, KAT2B, PRMT6 and SETD8 were upregulated by 50 μM of zearalenone exposure using PCR arrays, consistent with the results of global histone modifications. Zearalenone and alpha zearalenol also changed expression levels of the AhR, LXRα, PPARα, PPARɣ, L-fabp, LDLR, Glut2, Akt1 and HK2 genes, which are related to nuclear receptors and metabolic pathways. PPARɣ, a key regulator of lipid metabolism, was selected from among these genes for further analysis. The PPARɣ promoter reduced methylation significantly following zearalenone exposure. Taken together, the epigenetic mechanisms of DNA methylation and histone modifications may be key mechanisms in zearalenone toxicity. Furthermore, effects of zearalenone in metabolic pathways could be mediated by epigenetic modifications.

Understanding the Toxin Effects of β-Zearalenol and HT-2 on Bovine Granulosa Cells Using iTRAQ-Based Proteomics

Simple Summary

Zearalenone (ZEA) and T-2 are two important mycotoxins, which have deleterious effects on the health of humans and livestock. ZEA and its derivatives, α-zearalenol and β-zearalenol, disturb the hormonal homeostasis and lead to numerous problems in the reproductive system. The HT-2 toxin, as the primary metabolite of the T-2 toxin, exerts a series of toxic effects on humans and livestock. The T-2 toxin and its metabolite HT-2 toxin induce damages in multiple tissues, which include the reproductive system. However, toxic response profiles of these mycotoxins on bovine ovarian granulosa cells (bGCs) are unclear. In this study, we determined the importance of heat shock proteins, clarified oxidative stress, and the caspase-3 signaling cascade involved in the mycotoxin-treated toxic response. These results could provide new insights for future studies on prevention and treatment of reproductive problems caused by mycotoxins in bovines.

Abstract

Zearalenone (ZEA) and T-2 are the most common mycotoxins in grains and can enter the animal and human food-chain and cause many health disorders. To elucidate the toxic response profile, we stimulated bovine granulosa cells (GCs) with β-zearalenol or HT-2. Using isobaric tags for relative and absolute quantification (iTRAQ)-based proteomic, 178 and 291 differentially expressed proteins (DEPs, fold change ≥ 1.3 and p-value < 0.05) in β-zearalenol and HT-2 groups were identified, respectively. Among these DEPs, there were 66 common DEPs between β-zearalenol and HT-2 groups. These 66 DEPs were associated with 23 biological processes terms, 14 molecular functions terms, and 19 cellular components terms. Most heat shock proteins (HSPs) were involved in the toxic response. Reactive oxygen species accumulation, the endoplasmic reticulum (ER)-stress related marker molecule (GRP78), and apoptosis were activated. β-zearalenol and HT-2 inhibited oestradiol (E₂) production. These results emphasized the important function of HSPs, clarified oxidative stress, and demonstrated the caspase-3 signaling cascade involved in mycotoxin-treated toxic response, along with decreased E₂ production. This study offers new insights into the toxicity of β-zearalenol and HT-2 on ovarian granulosa cells.

Phosphatidylcholine could protect the defect of zearalenone exposure on follicular development and oocyte maturation

Zearalenone (ZEA) is a well-known exogenous endocrine disruptor and can lead to severe negative effects on the human and animal reproductive process. Using a follicle culture model, we have previously shown that ZEA exposure significantly affected the follicular development and antrum formation but the underlying mechanisms are not well known. Therefore, in this study, we explored the metabolomic changes of granulosa cell (GC) culture media with or without ZEA exposure. The results showed that ZEA significantly increased phosphatidylcholine or phosphatidyl ethanolamine adducts in culture medium. A comprehensive analysis with the metabolome data from follicular fluid of small and large antral follicles showed that lyso phosphatidylcholine (LPC) was accumulated during follicle growth, but was depleted by ZEA exposure. Exogenous supplement with LPC to the follicle growth media or oocyte maturation media can partly protect the defect of ZEA exposure on follicular antrum formation and oocyte maturation. Taken together, our results demonstrate that ZEA exposure hinders the follicular growth and exogenous LPC can practically protect the defect of ZEA on follicular development and oocyte maturation.

Zearalenone Exposure Induces the Apoptosis of Porcine Granulosa Cells and Changes Long Noncoding RNA Expression To Promote Antiapoptosis by Activating the JAK2-STAT3 Pathway

Zearalenone (ZEA), a pathogenic toxin produced by Fusarium, is widely detected in moldy feed materials. Previous studies have reported that ZEA exerts a harmful influence on animal reproductive systems; however, its effects on the changes of long noncoding RNAs (lncRNAs) remain unclear. Here, tackling this question, we performed RNA sequencing on porcine granulosa cells (GCs) after being exposed to 10 and 30 μM ZEA in vitro. The results showed that ZEA exposure observably changed the expression of lncRNAs in porcine GCs and increased the rate of apoptosis. Furthermore, Gene Ontology analysis showed that ZEA exposure induced variation of the Janus kinase 2 (JAK2)-signal transducer and activator of transcription 3 (STAT3) signaling pathway in porcine GCs. To verify our bioinformatics analysis, western blotting and immunofluorescence analysis were performed and the results demonstrated that porcine GCs after ZEA exposure increased the expression of key proteins in the JAK2-STAT3 signaling pathway. Further bioinformatics analysis found that MSTRG.22680 and MSTRG.23882 played a pivotal role in activating the JAK2-STAT3 signaling pathway. To summarize, our results throw light on the fact that ZEA exposure dramatically increases the apoptosis of porcine GCs and alters the expression of lncRNAs that play an antiapoptotic role in porcine GCs via activating the JAK2-STAT3 signaling pathway.

Alterations in global DNA methylation and metabolism-related genes caused by zearalenone in MCF7 and MCF10F cells

Zearalenone (ZEN) is a non-steroidal estrogenic mycotoxin produced by Fusarium fungi. ZEN has endocrine disruptor effects and could impair the hormonal balance. Here, we aimed at investigating possible effects of ZEN on metabolism-related pathways and its relation to epigenetic mechanisms in breast adenocarcinoma (MCF7) and breast epithelial (MCF10F) cells. Using the MTT and neutral red uptake (NRU) cell viability tests, IC₅₀ values of ZEN after 24 h were found to be 191 μmol/L and 92.6 μmol/L in MCF7 cells and 67.4 μmol/L and 79.5 μmol/L in MCF10F cells. A significant increase on global levels of 5-methylcytosine (5-mC%) was observed for MCF7 cells, correlating with the increased expression of DNA methyltransferases. No alterations were observed on levels of 5-mC% and expression of DNA methyltransferases for MCF10F cells. Further, at least threefold upregulation compared to control was observed for several genes related to nuclear receptors and metabolism in MCF7 cells, while some of these genes were downregulated in MCF10F cells. The most notably altered genes were IGF1, HK2, PXR, and PPARγ. We suggested that ZEN could alter levels of global DNA methylation and impair metabolism-related pathways.

Effect of grape seed extract on maternal toxicity and in utero development in mice treated with zearalenone

The aims of this study were to determine the polyphone content of grape seed extract (GSE) and to assess their protective effects against zearalenone (ZEN)-induced maternal toxicity and in utero development defects in mice. Five groups of pregnant mice were treated orally during days 6-13 of gestation as follows: control group, corn oil as vehicle (0.1 ml/mice)-treated group, ZEN-treated group (25 mg/kg b.w), GSE-treated group (150 mg/kg b.w.), and ZEN plus GSE-treated group. All animals were sacrificed on the 19th day of gestation and samples of bone marrow were collected for the micronucleus assay. The maternal and developmental toxicity were carried out. The HPLC analyses revealed that GES is rich in gallic acid, syringic acid, vanillin, quercetin, and coumaric acid. ZEN administration resulted in severe maternal and developmental toxicity which included an increase of micronuclei formation in bone marrow, decreased maternal weight gain, and litter weight. It also induces fetal growth retardation, increased number of the aborted dams and resorbed fetuses, abnormality of fetal bone ossification, and number of fetuses with a hematoma. GSE showed positive effects on the pregnant mice and the developing fetuses. Moreover, it counteracted the detrimental effects of ZEN in dams and fetuses. It could be concluded that polyphenols in GSE are a promising candidate to protect against ZEN toxicity in highly endemic areas.

Zearalenone: A Mycotoxin With Different Toxic Effect in Domestic and Laboratory Animals' Granulosa Cells

Zearalenone (ZEA), one of the most prevalent estrogenic mycotoxins, is mainly produced by Fusarium fungi and has been proven to affect the reproductive capacity of animals. Exposure of farm animals to ZEA is a global public health concern because of its toxicity and wide distribution in animal feeds. In vitro and in vivo experiments indicate that ZEA possesses estrogenic activity in mice, swine, Equus asinus and cattle. The precise mechanism of the reproductive toxicity of ZEA has not been established yet. This article reviews evidence on the deleterious effects of ZEA on mammalian folliculogenesis from early to final oogenesis stages. Such effects include impaired granulosa cell (GC) development and follicle steroidogenesis, reduced oocyte nest breakdown, damaged meiotic progression, poor fetal oocyte survival, accelerated primordial follicle activation and enhanced follicle atresia. These phenomena may result in reproductive and non-reproductive problems in domestic animals. In addition, emerging data indicates that ZEA may cause mRNA expression changes in the GCs. In general, E. asinus is more sensitive than swine to ZEA exposure. Finally, results of in vivo animal studies and in vitro tests are reported and discussed.

Isolation and characterization of the Bacillus cereus BC7 strain, which is capable of zearalenone removal and intestinal flora modulation in mice

Zearalenone (ZEN) causes serious diseases in both animals and humans and thereby leads to substantial economic losses. The elimination of ZEN contamination from food and feed is an important concern worldwide. This study aimed to screen a bacterium that can efficiently detoxify ZEN both in vitro and in vivo. A bacterium (designated BC7) with high ZEN-removing capability was isolated from mouldy contaminated feeds and characterized as Bacillus cereus based on biochemical and 16S rRNA sequencing analyses. BC7 could remove 100% and 89.31% of 10 mg/L ZEN in Luria-Bertani (LB) medium and simulated gastric fluid (GSF), respectively, within 24 h at 37 °C. The effects of BC7 on ZEN detoxification and on the intestinal flora were further evaluated using four groups of mice that were intragastrically administered normal saline, BC7 culture (CFU = 3.45 × 10⁸/mL), ZEN (10 mg/kg BW) or BC7 culture (CFU = 3.45 × 10⁸/mL) + ZEN (10 mg/kg BW) for 2 weeks. ZEN showed distinct reproductive and hepatic toxicity, as characterized by increased weights of the uterus and liver, altered levels of oestradiol (E2) and luteinizing hormone (LH), increased secretion of the liver injury biomarkers alanine transaminase (ALT) and aspartate transaminase (AST), and abnormal histological phenotypes for the uterus, ovary and liver. However, BC7 could significantly reduce all the above-mentioned adverse effects caused by ZEN with no harmful effect on the reproductive system and liver in mice. Moreover, the addition of BC7 could efficiently renormalize the ZEN-induced perturbation of the gut microbiota and significantly increase the abundance of Lactobacillus to maintain the health of the intestinal flora in mice. In conclusion, Bacillus cereus BC7 could be used as a potential feed additive to efficiently remove ZEN in vitro or in vivo and to normalize the disordered gut microbiota in mice.

Mycotoxin levels in the digestive tissues of immature gilts exposed to zearalenone and deoxynivalenol

Most plant materials are contaminated with small doses of Fusarium mycotoxins and its modified forms that exert subclinical toxic effects on humans and animals. The aim of this study was to evaluate the carry-over of zearalenone and deoxynivalenol (pure parent compounds) to intestinal and liver tissues during 6 weeks of exposure to mycotoxins administered per os to gilts. The experiment was performed on 36 gilts with average body weight of 25 ± 2 kg, divided into 2 groups: an experimental group (group E, administered zearalenone at 40 μg/kg BW and deoxynivalenol at 12 μg/kg BW daily with feed) and a control group administered placebo. Tissue saturation with mycotoxins was analysed by liquid chromatography in samples collected at weekly intervals. Six gilts were euthanized in each week of the study. The conducted analyses revealed: (i) a non-uniform increase in zearalenone levels in the duodenum, jejunum, ascending colon and the liver; and (ii) an increase in deoxynivalenol levels, mainly in the ileum, caecum, ascending colon and the transverse colon, and a minor increase in the liver. The degree of tissue saturation was determined by the type of mycotoxin, but not by the time of exposure.

Zearalenone Exposure Enhanced the Expression of Tumorigenesis Genes in Donkey Granulosa Cells via the PTEN/PI3K/AKT Signaling Pathway

Zearalenone (ZEA) is a natural contaminant existing in food and feed products that exhibits a negative effect on domestic animals’ reproduction. Donkeys possess high economic value in China and are at risk of exposure to ZEA. However, few information is available on ZEA-induced toxicity and no report on toxicity in donkeys can be found in scientific literature. We investigated the biological effects of ZEA exposure on donkey granulosa cells (dGCs) by using RNA-seq analysis. ZEA at 10 and 30 μM were administered to GCs within 72 h of in vitro culture. ZEA at 10 μM significantly altered the tumorigenesis associated genes in dGCs. Exposure to 10 and 30 μM ZEA treatment significantly reduced mRNA expression of PTEN, TGFβ, ATM, and CDK2 genes, particularly, the ZEA treatment significantly increased the expression of PI3K and AKT genes. Furthermore, immunofluorescence, RT-qPCR, and Western blot analysis verified the gene expression of ZEA-exposed GCs. Collectively, these results demonstrated the deleterious effect of ZEA exposure on the induction of ovarian cancer related genes via the PTEN/PI3K/AKT signaling pathway in dGCs in vitro.

Proanthocyanidins Protect Epithelial Cells from Zearalenone-Induced Apoptosis via Inhibition of Endoplasmic Reticulum Stress-Induced Apoptosis Pathways in Mouse Small Intestines

This study evaluated the protective effect of proanthocyanidins (PCs) on reducing apoptosis in the mouse intestinal epithelial cell model MODE-K exposed to zearalenone (ZEA) through inhibition of the endoplasmic reticulum stress (ERS)-induced apoptosis pathway. Our results showed that PCs could reduce the rate of apoptosis in MODE-K cells exposed to ZEA (p < 0.01). PCs significantly increased the ZEA-induced antioxidant protective effects on the enzymes superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) and on the content of GSH. PCs also significantly decreased the ZEA-induced increase in the content of malondialdehyde (MDA). The analysis indicated that ZEA increased both mRNA and protein expression levels of C/EBP homologous protein (CHOP), GRP78, c-Jun N-terminal kinase (JNK), and cysteinyl aspartate specific proteinase 12 (caspase-12) (p < 0.05), which are related to the ERS-induced apoptosis pathway. ZEA decreased levels of the pro-apoptotic related protein Bcl-2 (p < 0.05) and increased the anti-apoptotic related protein Bax (p < 0.05). Co-treatment with PCs was also shown to significantly reverse the expression levels of these proteins in MODE-K cells. The results demonstrated that PCs could protect MODE-K cells from oxidative stress and apoptosis induced by ZEA. The underlying mechanism may be that PCs can alleviate apoptosis in mouse intestinal epithelial cells by inhibition of the ERS-induced apoptosis pathway.

Differentiation of sow and mouse ovarian granulosa cells exposed to zearalenone in vitro using RNA-seq gene expression

Zearalenone (ZEA), a natural contaminant found in feed, has been shown to have a negative impact on domestic animal reproduction, particularly in pigs. There are species-specific differences in the ZEA-induced toxicity pattern. Here, we investigated the different biological effects of ZEA exposure on porcine and mouse granulosa cells, using RNA-seq analysis. We treated murine and porcine granulosa cells with 10 μM and 30 μM ZEA during 72 h of culturing, in vitro. The results showed that 10 μM ZEA exposure significantly altered mitosis associated genes in porcine granulosa cells, while the same treatment significantly altered the steroidogenesis associated genes in mouse granulosa cells. Exposure to 30 μM ZEA resulted in significantly up-regulated expression of inflammatory related genes in porcine granulosa cells as well as the cancer related genes in mouse granulosa cells. Similarly, 30 μM ZEA exposure significantly decreased the expression of tumor suppressor factors in the mouse granulosa cells. Furthermore, immunofluorescence, RT-qPCR as well as western-blot analysis verified the different expression of related genes in ZEA exposed porcine and mouse granulosa cells. Collectively, these results illustrate the presence of species differences with regards to ZEA effects between porcine and mouse ovarian granulosa cells, in vitro.

Mycotoxin zearalenone exposure impairs genomic stability of swine follicular granulosa cells in vitro

Zearalenone (ZEA), a metabolite of Fusarium fungi, is commonly found on moldy grains. Because it can competitively combine to estrogen receptor to disrupt estrogenic signaling, it has been reported to have serious adverse effects on animal reproduction systems. In order to explore the genotoxic effects of ZEA exposure on ovarian somatic cells, porcine granulosa cells were exposed to 10 μM and 30 μM ZEA for 24 or 72 h in vitro. The results showed that ZEA exposure for 24 h remarkably reduced the proliferation of porcine granulosa cells in a dose-dependent manner as determined by MTT analysis and flow cytometry. Furthermore, exposure to ZEA for 72 h induced apoptosis, and RNA sequence analysis also revealed that the expression of apoptosis related genes were altered. RT-qPCR, immunofluorescence and western blot analysis further confirmed the expression of DNA damage and repair related genes (γ-H2AX, BRCA1, RAD51 and PRKDC) were increased in ZEA exposed granulosa cells. When the estrogen antagonist, tamoxifen, was added with ZEA in the culture medium, the DNA damage and repairment by ZEA returned to normal level. Collectively, these results illustrate that ZEA disrupts genome stability and inhibits growth of porcine granulosa cells via the estrogen receptors which may promote granulosa cell apoptosis when the DNA repair system is not enough to rescue this serious damage.

The role of autophagy during murine primordial follicle assembly

It is generally accepted that significant germ cell loss occurs during the establishment of the primordial follicle pool in most mammalian ovaries around the time of birth. However, the underlying mechanisms responsible for these processes remain largely unknown. In this investigation, we explored the role of autophagy during the establishment of the primordial follicle pool and found that autophagy was active in this process. Our data suggested that 17.5 dpc ovaries treated with rapamycin displayed a delay in germ cell cyst breakdown resulting in more oocytes at day 5 of treatment, while, ovaries that treated with 3-MA showed the opposite effect. We found that rapamycin treatment promoted autophagy and depressed cell apoptosis increasing the number of NOBOX positive oocytes. Furthermore, our results also revealed that epigenetic regulator, Sirt1, plays a role in germ cell loss. An epigenetic inhibitor or RNAi treatment of Sirt1, showed an increased level of H4K16ac and a decreased level of autophagy. Thus, these data indicate that autophagy prevents germ cell over loss during the establishment of primordial follicle pool, and this process may be influenced by Sirt1-invovled epigenetic regulation.

Protective effect of proanthocyanidin on mice Sertoli cell apoptosis induced by zearalenone via the Nrf2/ARE signalling pathway

This study evaluated the protective effect of proanthocyanidin (PC) on the cytotoxicity of the Sertoli cell TM4 of mice, as induced by zearalenone (ZEA). Flow cytometry was used to detect the apoptosis rate of cells in each group. The activities of antioxidant enzymes and the content of antioxidant substances were detected by using a proprietary kit; the RT-PCR method was used to detect the expression level of mRNA, the related genes of Nrf2/ARE signal pathway, the nuclear factor E2 related factor 2 (Nrf2), heme oxygenase 1 (HO-1), glutathione peroxidase (GSH-Px), quinone oxidoreductase 1 (NQO1), γ-glutamylcysteine synthetase (γ-GCS) and the expression level of mRNA, the apoptosis-related genes, Bcl-2 and Bax; the Western-blot method was used to detect the protein expression levels of Nrf2, GSH-Px, HO-1, γ-GCS and NQO1 in each group. Our results showed that PC could reduce the apoptosis rate of the TM4 cells exposed to ZEA (p < 0.01); PC could enhance the decrease in the activities of T-SOD and GSH-Px induced by ZEA (p < 0.05), reduce the increase in the content of MDA, as caused by ZEA; PC could significantly up-regulate the down-regulation levels of the mRNA and protein of Nrf2, GSH-Px, HO-1, γ-GCS and NQO1 induced by ZEA. PC could enhance the decrease in the mRNA expression level of Bcl-2 and down-regulate the mRNA expression of Bax induced by ZEA (p < 0.05). These results demonstrated that PC conferred protective effects against oxidative damage and apoptosis of TM4 cells induced by ZEA. The protection mechanism of PC on TM4 cells might act through the activation of the Nrf2/ARE signalling pathway.

RNA-seq based gene expression analysis of ovarian granulosa cells exposed to zearalenone in vitro: significance to steroidogenesis

Zearalenone (ZEA) is a natural contaminant of various food and feed products representing a significant problem worldwide. Since the occurrence of ZEA in grains and feeds is frequent, the present study was carried out to evaluate the possible effects of ZEA on steroid production and gene expression of porcine granulosa cells, using RNA-seq analysis. Porcine granulosa cells were administered 10 μM and 30 μM ZEA during 72 h of culture in vitro. Following ZEA treatment the gene expression profile of control and exposed granulosa cells was compared using RNA-seq analysis. The results showed that in the exposed granulosa cells ZEA significantly altered the transcript levels, particularly steroidogenesis associated genes. Compared with the control group, 10 μM and 30 μM ZEA treatment significantly increased the mRNA expression of EDN1, IER3, TGFβ and BDNF genes and significantly reduced the mRNA expression of IGF-1 and SFRP2 genes. In particular, ZEA significantly decreased the expression of genes essential for estrogen synthesis including FSHR, CYP19A1 and HSD17β in granulosa cells. Furthermore, Q-PCR and Western-blot analysis also confirmed reduced expression of these genes in ZEA exposed granulosa cells. These effects were associated with a significant reduction of 17β-estradiol concentrations in the culture medium of granulosa cells. Collectively, these results demonstrated a concretely deleterious effect of ZEA exposure on the mRNA expression of steroidogenesis related genes and the production of steroid hormones in porcine ovarian granulosa cells in vitro.