BPA's transgenerational disturbance to transcription of ovarian steroidogenic genes in rare minnow Gobiocypris rarus via DNA and histone methylation

A novel long non-coding RNA linc-93.2 participates in bisphenol induced oxidative stress and macrophage polarization in red common carp (Cyprinus carpio)

Previous studies show that bisphenol A (BPA) and its analogs induce oxidative stress and promote inflammatory response. However, the key molecules in regulating this process remain unclear. Here, we report significant inductive effects of BPA and bisphenol AF (BPAF) on a newly found long non-coding RNA linc-93.2 accompanied by oxidative stress and activation of pro-inflammatory pathways in treated fish and fish primary macrophages. Silencing linc-93.2 in fish primary macrophages in vitro or fish in vivo significantly promotes the expression of anti-oxidative stress-related genes and anti-inflammatory cytokines. This inhibition of pro-inflammatory cytokine expression, showing cell status disruption towards to M2 polarization. Followed by exposure to BPA or BPAF, silencing linc-93.2 in vitro or in vivo significantly attenuates the increased production of reactive oxygen species and malondialdehyde level aroused by bisphenol treatment, possibly owing to the enhancement of total antioxidant capacity observed in cells and tissue after linc-93.2 knockdown. RNA-sequencing further revealed regulation of nuclear factor-kappa b (NF-κB) in linc-93.2's downstream network, combining with our previous observation on the upstream regulation of linc-93.2 via NF-κB, which together suggest a critical role of linc-93.2 in promoting NF-κB positive feedback loop that may be an important molecular event initiating the immunotoxicity of bisphenols.

The flame retardant triphenyl phosphate alters the epigenome of embryonic cells in an aquatic in vitro model

Triphenyl phosphate (TPhP) is an organophosphate flame retardant and plasticizer that is added to a wide variety of consumer and industrial products. It is also a ubiquitous environmental pollutant. Exposure to TPhP has been shown to alter gene expression in metabolic and estrogenic signaling pathways in in vitro and in vivo models of a variety of species, and as such, is considered to be an endocrine disrupting chemical. Exposure to endocrine disrupting chemicals is increasingly being associated with changes to the epigenome, especially during embryonic development. The aim of this study was to evaluate whether TPhP exposure in aquatic ecosystems has the ability to alter the epigenome in two immortal cell lines derived from trout (Oncorhynchus mykiss). This study assessed whether 24 h exposure to TPhP resulted in changes to histone modification and DNA methylation profiles in steelhead trout embryonic cells and rainbow trout gill epithelial cells. Results show that several epigenetic modifications on histone H3 and DNA methylation are altered in the embryonic cells following TPhP exposure, but not in the gill epithelial cells. Specifically, histone H3 acetylation, histone H3 mono-methylation and global DNA methylation were found to be reduced. The alterations of these epigenetic modification profiles in the embryonic cells suggest that exposure to TPhP during fetal development may alter gene expression in the developing embryo, likely in metabolic and estrogenic pathways. The impacts to the epigenome determined in this study may even carry multigenerational detrimental effects on human and ecosystem health, which requires further investigation.

Recent advances of piezo-catalysis and photocatalysis for efficient environmental remediation

The efficient degradation of organic pollutants in diverse environmental matrices can be achieved through the synergistic application of piezo-catalysis and photocatalysis. The focus of this study is on understanding the fundamental principles and mechanisms that govern the collaborative action of piezoelectric and photocatalytic materials. Piezoelectric nanomaterials, under mechanical stress, generate piezo-potential, which, when coupled with photocatalysts, enhances the generation and separation of charge carriers. The resulting cascade of redox reactions promotes the degradation of a wide spectrum of organic pollutants. The comprehensive investigation involves a variety of experimental techniques, including advanced spectroscopy and microscopy, to elucidate the intricate interplay between mechanical and photoinduced processes. The influence of key parameters, such as material composition, morphology, and external stimuli on the catalytic performance, is systematically explored. This study contributes to the increasing knowledge of environmental remediation and lays the foundation for the development of advanced technologies using piezo and photocatalysis for sustainable pollutant removal.

The Interplay between Endocrine-Disrupting Chemicals and the Epigenome towards Metabolic Dysfunction-Associated Steatotic Liver Disease: A Comprehensive Review

Metabolic dysfunction-associated steatotic liver disease (MASLD), described as the most prominent cause of chronic liver disease worldwide, has emerged as a significant public health issue, posing a considerable challenge for most countries. Endocrine-disrupting chemicals (EDCs), commonly found in daily use items and foods, are able to interfere with nuclear receptors (NRs) and disturb hormonal signaling and mitochondrial function, leading, among other metabolic disorders, to MASLD. EDCs have also been proposed to cause transgenerationally inherited alterations leading to increased disease susceptibility. In this review, we are focusing on the most prominent linking pathways between EDCs and MASLD, their role in the induction of epigenetic transgenerational inheritance of the disease as well as up-to-date practices aimed at reducing their impact.

Environmental bisphenol A disrupts methylation of steroidogenic genes in the ovary of Paradise threadfin Polynemus paradiseus via abnormal DNA methylation: Implications for human exposure and health risk assessment

Bisphenol A, endocrine-disrupting chemicals (EDCs) impacting disease development via epigenetic modifications, is crucial in transcriptional regulation. However, ecotoxicology's limited exploration of epigenetics prompted our study's objective: examining the extended exposure of riverine Bisphenol A (BPA), a potent EDC, on DNA methylation during female paradise threadfin (Polynemus paradiseus) reproductive maturation. Assessing BPA contamination in riverine water, we collected fish samples from two locations with distinct contamination levels. In the highly contaminated region (Hc), we observed elevated DNA methylation in aromatase (7.5-fold), 20β-HSD (3-fold), and FSHR (2-fold) genes. Hormone receptor investigation highlighted an escalating connection between transcriptional hyper-methylation and contamination levels. Additionally, our study revealed a positive correlation between oocyte growth and global DNA methylation, suggesting BPA's potential to modify DNA methylation in female paradise threadfins. This effect likely occurs through changes in hormone receptor expression, persisting throughout oocyte maturation. Notably, our research, the first of its kind in estuarine areas, confirmed BPA contamination in paradise threadfins, raising concerns about potential health risks for humans.

Study on epigenotoxicity, sex hormone synthesis, and DNA damage of benzo[a]pyrene in the testis of male Ruditapes philippinarum

Research on the mechanisms of reproductive toxicity caused by persistent organic pollutants (POPs) in marine animals has received significant attention. One group of typical POPs, called polycyclic aromatic hydrocarbons (PAHs), has been found to cause various reproductive toxicities in aquatic organisms, including epigenotoxicity, reproductive endocrine disruption, DNA damage effects and other reproductive toxicity, thereby affecting gonadal development. Interestingly, male aquatic animals are more susceptible to the disturbance and toxicity of environmental pollutants. However, current studies primarily focus on vertebrates, leaving a large gap in our understanding of the reproductive toxicity and mechanisms of PAHs interference in marine invertebrates. In this study, male Ruditapes philippinarum was used as an experimental subject to investigate reproduction-related indexes in clams under the stress of benzo[a]pyrene (B[a]P) at different concentrations (0, 0.8, 4 and 20 μg/L) during the proliferative, growth, maturity, and spawning period. We analyzed the molecular mechanisms of reproductive toxicity caused by PAHs in marine bivalves, specifically epigenotoxicity, reproductive endocrine disruption, and gonadal damage-apoptotic effect. The results suggest that DNA methylation plays a crucial role in mediating B[a]P-induced reproductive toxicity in male R. philippinarum. B[a]P may affect sex hormone levels, impede spermatogenesis and testis development in clams, by inhibiting the steroid hormone synthesis pathway and downregulating genes critical for cell proliferation, testis development, and spermatid expulsion. Moreover, the spermatids of male R. philippinarum were severely impaired under the B[a]P stress, leading to reduced reproductive performance in the clams. These findings contribute to a better understanding of the reproductive toxicity response of male marine invertebrates to POPs stress.

Warming and pollution interact to alter energy transfer efficiency, performance and fitness across generations in zebrafish (Danio rerio)

Energy transfer efficiency across different trophic levels, from food to new biomass, can determine population dynamics and food-web function. Here we show that the energy needed to produce a unit of new biomass increases with warming and exposure to bisphenol A (BPA), an endocrine disrupting compound. These environmental effects are at least partially transmitted across generations via DNA methylation. We raised parental (F0) and their offspring (F1) zebrafish (Danio rerio) of two genotypes (DNA methyltransferase 3a knock-out [DNMT3a-/-] and wild type [DNMT3a+/+]) at different temperatures (24 and 30 °C), with and without BPA (0 and 10 μg l-1) to test whether the effects of BPA are i) temperature specific, ii) mediated by DNA methylation, and iii) transmitted across generations even if offspring are not exposed. All experimental factors interacted to influence growth in length and mass, and metabolic rates with the result that wild-type F0 and F1 fish experienced the greatest energetic cost of growth under warm conditions in the presence of BPA. However, this response was not observed in DNMT3a-/- fish, indicating that DNA methylation is at least partly responsible for mediating these effects. Under the same conditions (warm + BPA) wild-type parents had reduced swimming performance, and reduced fecundity, and offspring embryonic survival was reduced significantly; genotype affected these responses significantly. Our results indicate that the conditions that are becoming increasingly common globally - warming and endocrine disrupting compounds from plastic pollution and production - can have detrimental effects on energy transfer efficiency and thereby potentially on food-web structure. These effects can be transmitted across generations even if offspring are not exposed to the pollutant, and are likely to have ramifications for conservation and fisheries.

Alteration of epigenetic methyl and acetyl marks by postnatal chromium(VI) exposure causes apoptotic changes in the ovary of the F1 offspring

Hexavalent chromium, Cr(VI), is a heavy metal endocrine disruptor used widely in various industries worldwide and is considered a reproductive toxicant. Our previous studies demonstrated that lactational exposure to Cr(VI) caused follicular atresia, disrupted steroid hormone biosynthesis and signaling, and delayed puberty. However, the underlying mechanism was unknown. The current study investigated the effects of Cr(VI) exposure (25 ppm) during postnatal days 1-21 via dam's milk on epigenetic alterations in the ovary of F1 offspring. Data indicated that Cr(VI) disrupted follicle development and caused apoptosis by increasing DNMT3a /3b and histone methyl marks (H3K27me3 and H3K9me3) along with decreasing histone acetylation marks (H3K9ac and H3K27ac). Our study demonstrates that exposure to Cr(VI) causes changes in the epigenetic marks, partially contributing to the transcriptional repression of genes regulating ovarian development, cell proliferation (PCNA), cell survival (BCL-XL and BCL-2), and activation of genes regulating apoptosis (AIF and cleaved caspase-3), resulting in follicular atresia. The current study suggests a role for epigenetics in Cr(VI)-induced ovotoxicity and infertility.

Bisphenol A exposure decreases sperm production and male fertility through inhibition PCBP2 expression

Growing evidence suggests that the exposure of bisphenol A (BPA), an endocrine disruptor that commonly present in the environment, can impair reproduction. However, conflicting results have been reported, and the underlying mechanism has not been fully understood. In this study, 3-week-old male mice were oral exposed to 50 mg/kg/d BPA or equivalent corn oil for 28 days. Their testis and epididymis were then collected for morphology examination by HE stains. The number of sperm was counted, and the morphology was analyzed by PNA (peptide nucleic acid) and pap staining. Fertilization capacity and successful rate were analyzed after mating with wide-type females. Spermatid DNA damage and apoptosis were evaluated by DFI, γH2AX stain, and TUNEL assay. RNA sequencing analysis was conducted to identify differentially expressed genes in testicular tissue of mice exposed to BPA. RNA interference was used to verify the regulatory mechanism of BPA exposure on gene expression in GC-2 cells. Our data showed that the total number of sperm was decreased and the morphology was impaired in BPA-exposed mice. In addition, the serum testosterone level and fertilization efficiency were also reduced. Mechanism studies showed that BPA could suppress the expression of PCBP2, a key regulatory gene in spermatid development, by activating the EZH2/H3K27me3. In conclusion, we found that BPA exposure can impair spermatid development via affecting key gene expression that is at least partially due to epigenetic modification.

Exploring the Effects of Rearing Densities on Epigenetic Modifications in the Zebrafish Gonads

Rearing density directly impacts fish welfare, which, in turn, affects productivity in aquaculture. Previous studies have indicated that high-density rearing during sexual development in fish can induce stress, resulting in a tendency towards male-biased sex ratios in the populations. In recent years, research has defined the relevance of the interactions between the environment and epigenetics playing a key role in the final phenotype. However, the underlying epigenetic mechanisms of individuals exposed to confinement remain elucidated. By using zebrafish (Danio rerio), the DNA methylation promotor region and the gene expression patterns of six genes, namely dnmt1, cyp19a1a, dmrt1, cyp11c1, hsd17b1, and hsd11b2, involved in the DNA maintenance methylation, reproduction, and stress were assessed. Zebrafish larvae were subjected to two high-density conditions (9 and 66 fish/L) during two periods of overlapping sex differentiation of this species (7 to 18 and 18 to 45 days post-fertilization, dpf). Results showed a significant masculinization in the populations of fish subjected to high densities from 18 to 45 dpf. In adulthood, the dnmt1 gene was differentially hypomethylated in ovaries and its expression was significantly downregulated in the testes of fish exposed to high-density. Further, the cyp19a1a gene showed downregulation of gene expression in the ovaries of fish subjected to elevated density, as previously observed in other studies. We proposed dnmt1 as a potential testicular epimarker and the expression of ovarian cyp19a1a as a potential biomarker for predicting stress originated from high densities during the early stages of development. These findings highlight the importance of rearing densities by long-lasting effects in adulthood conveying cautions for stocking protocols in fish hatcheries.

Decreased expression of Chrna4 by METTL3-mediated m6A modification participates in BPA-induced spatial memory deficit

Bisphenol A (BPA), a widely used endocrine disruptor, has been implicated in cognitive impairment via epigenetic machinery. N6-methyl adenosine (m6A) has recently emerged as a new epigenetic factor that influences cognition, but the role of m6A in BPA induced cognitive deficits has not been explored yet. In this study, we found increased global m6A abundance accompanied with elevated expression of methyltransferase-like 3 (METTL3) in hippocampal neurons following BPA exposure. Inhibition of METTL3 activity by selective METTL3 inhibitor 2457 (STM) in cultured neurons abolished BPA induced m6A upregulation and abnormal synaptic transmission. Additionally, knockdown of METTL3 in hippocampus abrogated BPA induced learning and memory deficit in rats. Further study showed that m6A modification was enriched in mRNA of cholinergic receptor nicotinic alpha 4 subunit (Chrna4). Inhibition of METTL3 either by STM or shRNA restored BPA induced downregulation of Chrna4, suggesting that Chrna4 may be a potential target involved in BPA induced neurotoxicity that modified by m6A. Collectively, our findings demonstrated that METTL3 mediated m6A modification was involved in BPA induced cognitive deficit with Chrna4 as a potential target, which enriched our understanding of the role of epigenetics (RNA modifications) in BPA induced neurotoxicity and provided new insights into BPA or its substitutes induced damages in other organs.

Genetic and Epigenetic Evidence for Nonestrogenic Disruption of Otolith Development by Bisphenol A in Zebrafish

Bisphenol A (BPA) is a well-known endocrine-disrupting chemical (EDC) that has estrogenic activities. In addition to disrupting reproductive development and function via estrogenic signaling pathways, BPA can also interfere with nonreproductive functions through nonestrogenic pathways; however, the mechanisms underlying such nonestrogenic activities are not well understood. In this study, we demonstrated that BPA could disrupt otolith formation during the early development of zebrafish with long-lasting ethological effects. Using multiple mutants of estrogen receptors, we provided strong genetic evidence that the BPA-induced otolith malformation was independent of estrogen signaling. Transcriptome analysis revealed that two genes related to otolith development, otopetrin 1 (otop1) and starmaker (stm), decreased their expression significantly after BPA exposure. Knockout of both otop1 and stm genes could phenocopy the BPA-induced otolith malformation, while microinjection of their mRNAs could rescue the BPA-induced abnormalities of otolith formation. Further experiments showed that BPA inhibited the expression of otop1 and stm by activating the MEK/ERK-EZH2-H3K27me3 signaling pathway. Taken together, our study provided comprehensive genetic and molecular evidence that BPA induced the otolith malformation through nonestrogenic pathway during zebrafish early development and its activities involved epigenetic control of key genes (e.g., otop1 and stm) participating in otolith formation.

Bisphenol A has a sex-dependent disruptive effect on hepatic lipid metabolism in zebrafish

Bisphenol A (BPA) is an endocrine disruptor that has adverse effects on lipid metabolism. However, most of the current studies on the effects of BPA on lipid metabolism in fish have focused on middle- and short-term exposure tests. The aim of this study was to investigate the effects of long-term BPA exposure on liver lipid metabolism in zebrafish. Post-fertilization embryos were exposed to environmentally relevant concentrations of BPA for 120 days, and the changes in triglyceride (TG), total cholesterol (TC) levels, and gene expression related to liver lipid metabolism were investigated in both male and female fish. The results showed that long-term exposure to BPA led to lipid deposition in liver, and there was a sex difference. In the liver of female fish, there was higher lipid transport and synthesis at low concentration of BPA, while overall metabolic levels were increased at high concentration of BPA. In contrast, BPA showed a dose-dependent effect on the lipid deposition in male fish. The expression of mRNA of TG transport-related and lipid synthesis-related genes was significantly up-regulated and the expression of genes related to lipid catabolism, was significantly down-regulated with increasing BPA dose. Taken together, our results indicate that long-term exposure to BPA can increase lipid deposition in a gender-specific manner. This may be due to the different responses of lipid metabolism related genes to BPA in male and female zebrafish. These results will provide a new reference for a deeper understanding of the ecotoxicological effects of BPA on aquatic animals.

Bisphenol A interferes with lncRNA Fhadlos2 and RUNX3 association in adolescent mouse ovary

Bisphenol A (BPA) has a number of adverse effects on the reproductive development of females. In particular, the mechanism of disruption of ovarian development in adolescent mice is still unclear. Based on transcriptome sequencing results, a differentially expressed lncRNA, Fhad1os2, was detected in the ovaries of BPA-exposed pubertal mice. In our study, the lncRNA Fhad1os2, localized in the ovarian granulosa cell cytoplasm, could regulate the proliferation of mouse ovarian granulosa cells. Mechanistically, the results of RNA pull-down experiments as well as mass spectrometry analysis showed that ERα, an interfering signaling molecule of BPA, could directly bind lncRNA Fhad1os2 and decrease the transcription of lncRNA Fhad1os2 in response to the estrogen-like effect of BPA. BPA exposure also caused abnormal lncRNA Fhad1os2 pulldown protein-related signaling pathways in the ovaries of adolescent mice. Furthermore, lncRNA Fhad1os2 interacted with RUNX3, a transcription factor related to follicle development and hormone synthesis. As a negative regulator, lncRNA Fhad1os2 transactivated the expression of Runx3, which in turn induced RUNX3 to positively regulate aromatase (Cyp19a1) expression in mouse ovarian granulosa cells and promote estrogen synthesis. In conclusion, our study indicates that BPA exposure interferes with ERα-regulated lncRNA Fhad1os2 interactions with RUNX3 in pubertal mice, affecting estrogen synthesis in mouse granulosa cells and contributing to premature ovarian maturation in pubertal mice.

Estrogenic and non-estrogenic effects of bisphenol A and its action mechanism in the zebrafish model: An overview of the past two decades of work

Bisphenol A (BPA) is the most simple and predominant component of the Bisphenol family. BPA is widely present in the environment and the human body as a result of its extensive usage in the plastic and epoxy resins of consumer goods like water bottles, food containers, and tableware. Since the 1930s, when BPA's estrogenic activity was first observed, and it was labeled as a "mimic hormone of E2", studies on the endocrine-disrupting effects of BPA then have been widely conducted. As a top vertebrate model for genetic and developmental studies, the zebrafish has caught tremendous attention in the past two decades. By using the zebrafish, the negative effects of BPA either through estrogenic signaling pathways or non-estrogenic signaling pathways were largely found. In this review, we tried to draw a full picture of the current state of knowledge on the estrogenic and non-estrogenic effects of BPA with their mechanisms of action through the zebrafish model of the past two decades, which may help to fully understand the endocrine-disrupting effects of BPA and its action mechanism, and give a direction for the future studies.

The State of Research and Weight of Evidence on the Epigenetic Effects of Bisphenol A

Bisphenol A (BPA) is a high-production-volume chemical with numerous industrial and consumer applications. BPA is extensively used in the manufacture of polycarbonate plastics and epoxy resins. The widespread utilities of BPA include its use as internal coating for food and beverage cans, bottles, and food-packaging materials, and as a building block for countless goods of common use. BPA can be released into the environment and enter the human body at any stage during its production, or in the process of manufacture, use, or disposal of materials made from this chemical. While the general population is predominantly exposed to BPA through contaminated food and drinking water, non-dietary exposures through the respiratory system, integumentary system, and vertical transmission, as well as other routes of exposure, also exist. BPA is often classified as an endocrine-disrupting chemical as it can act as a xenoestrogen. Exposure to BPA has been associated with developmental, reproductive, cardiovascular, neurological, metabolic, or immune effects, as well as oncogenic effects. BPA can disrupt the synthesis or clearance of hormones by binding and interfering with biological receptors. BPA can also interact with key transcription factors to modulate regulation of gene expression. Over the past 17 years, an epigenetic mechanism of action for BPA has emerged. This article summarizes the current state of research on the epigenetic effects of BPA by analyzing the findings from various studies in model systems and human populations. It evaluates the weight of evidence on the ability of BPA to alter the epigenome, while also discussing the direction of future research.

Bisphenol S reduces locomotor performance and modifies muscle protein levels but not mitochondrial bioenergetics in adult zebrafish

Human activity has now introduced novel chemicals into most aquatic ecosystems. Endocrine-disrupting compounds originating from plastic pollution and manufacture can have pronounced biological effects by disrupting hormone-mediated processes. Bisphenol A (BPA) is one of the most commonly produced endocrine-disrupting compounds, which interferes with signalling by a broad range of hormones. In recognition of its potentially harmful effects, BPA is being replaced by substitutes such as bisphenol S (BPS). However, toxicological studies revealed that BPS too can bind to hormone receptors and disrupt signalling, particularly of thyroid hormone. The aim of this study was to test whether BPS exposure impacts locomotor performance and muscle function in zebrafish (Danio rerio). Locomotor performance depends on thyroid hormone signalling, and it is closely related to fitness so that its disruption can have negative ecological and evolutionary consequences. BPS exposure of 15 μg l^-1 [∼60 nM] and 30 μg l^-1 (but not 60 μg l^-1) decreased sustained swimming performance (U_crit), but not sprint speed. In a fully factorial design, we show that living in flowing water increased U_crit compared to a still water control, and that BPS reduced U_crit under both conditions but did not eliminate the training effect. In a second factorial experiment, we show that BPS did not affect mitochondrial bioenergetics in skeletal muscle (state 3 and 4 rates, respiratory control ratios, ROS production), but that induced hypothyroidism decreased state 3 and 4 rates of respiration. However, both hypothyroidism and BPS exposure decreased activity of AMP-activated protein kinase (pAMPK:total AMPK) but increased protein levels of myocyte enhancer factor 2, and slow and fast myosin heavy chains. Our data indicate that BPS is not a safe alternative for BPA and that exposure to BPS can have ecological consequences, which are likely to be at least partly mediated via thyroid hormone disruption.

Isolation of female germline stem cells from neonatal piglet ovarian tissue and differentiation into oocyte-like cells

It has been generally accepted that the number of oocyte pool in mammalian ovaries is limited and irreversibly consumed throughout the adulthood until menopause, which has been challenged by the existence of female germline stem cells (FGSCs) and their differentiation potentials into oocytes through mitosis. However, there have been a few reports about the existence of porcine FGSCs (pFGSCs) in the neonatal piglet ovarian tissues. In this study, the pFGSCs were isolated from the one day post partum (1 dpp) piglet ovaries by a differential anchoring velocity method combined with the magnetic cell sorting (MACS) using VASA antibody. The gene expression levels and in vitro differentiation potentials of pFGSCs were subsequently analyzed. The results showed that Oct4, C-kit, Vasa, Stella, Ifitm3 and Dazl were expressed in the pFGSCs. A small portion of pFGSCs (2.81 ± 0.76%) spontaneously differentiated into oocyte-like cells (OLCs) with a mean diameter of 50 μm and gene expressions of Vasa, Ifitm3, Blimp1, Gdf9, Zp3, Dazl and Stella. Compared with that of the spontaneous differentiation system, the differentiation rates of pFGSCs into OLCs were significantly increased after the co-supplementations of porcine follicular fluid (PFF) and retinoic acid (RA). Taken together, these above results revealed the direct evidences for the existence of pFGSCs in 1 dpp piglet ovaries and the in vitro differentiation potential of pFGSCs into OLCs, benefiting future research related to the in vitro establishment of livestock FGSCs and the in vitro differentiation of pFGSCs.

The brominated flame retardant, 1,2,5,6-tetrabromocyclooctane (TBCO), causes multigenerational effects on reproductive capacity of Japanese medaka (Oryzias latipes)

Exposure of fishes to endocrine disrupting chemicals (EDCs) during early development can induce multigenerational and transgenerational effects on reproduction. Both in vivo and in vitro studies have demonstrated that the brominated flame retardant, 1,2,5,6-tetrabromocyclooctane (TBCO), is an EDC. The present study investigated whether TBCO has mutigenerational and/or transgenerational effects on the reproductive performance of Japanese medaka (Oryzias latipes). Sexually mature fish (F0 generation) were fed either a control diet or a low (40.6 μg/g) or high (1034.4 μg/g) diet containing TBCO, and three generations of embryos were reared to determine reproductive performance using a standard 21-day reproduction assay. Concentrations of TBCO in eggs (F1 generation) from F0 fish given the low and high diets were 711.3 and 2535.5 ng/g wet weight, respectively. Cumulative fecundity of the F1 generation in the low and high treatment were reduced by 33.9% and 33.3%, respectively, compared to the control. In the F2 generation, cumulative fecundity of the low treatment returned to the level of the controls, but the high treatment was decreased by 29.8%. There was no decrease in cumulative fecundity in the F3 generation compared to the controls. Mechanistically, mRNA abundances of cholesterol side chain cleavage enzyme (cyp11a), aromatase (cyp19a), and luteinizing hormone receptor (lhr) were differentially expressed in gonads from F1 females, suggesting that TBCO might cause developmental reprogramming that disrupts steroidogenesis leading to decreased fecundity. However, concentrations of E2 in plasma and mRNA abundance of vitellogenin in liver were not significantly different compared to controls suggesting a mechanism other than disruption of steroidogenesis or vitellogenesis. Mechanistically, no effects were observed in the F2 or F3 generation. Overall, results suggest that TBCO has multigenerational effects on the reproductive performance of Japanese medaka. However, no transgenerational effects were observed as the F3 generation fully recovered. The mechanism by which multigenerational effects were induced is not known.

Developmental origins of adult diseases

The occurrence and mechanisms of developmental adult diseases have gradually attracted attention in recent years. Exposure of gametes and embryos to adverse environments, especially during plastic development, can alter the expression of certain tissue-specific genes, leading to increased susceptibility to certain diseases in adulthood, such as diabetes, cardiovascular disease, neuropsychiatric, and reproductive system diseases, etc. The occurrence of chronic disease in adulthood is partly due to genetic factors, and the remaining risk is partly due to environmental-dependent epigenetic information alteration, including DNA methylation, histone modifications, and noncoding RNAs. Changes in this epigenetic information potentially damage our health, which has also been supported by numerous epidemiological and animal studies in recent years. Environmental factors functionally affect embryo development through epimutation, transmitting diseases to offspring and even later generations. This review mainly elaborated on the concept of developmental origins of adult diseases, and revealed the epigenetic mechanisms underlying these events, discussed the theoretical basis for the prevention and treatment of related diseases.

Transgenerational effects of parental bisphenol S exposure on zebrafish (Danio rerio) reproduction

Bisphenol S (BPS) is extensively used for production of polycarbonates and other commodities, and is often detected in environment and biota. Parental BPS exposure has been reported to interfere with reproductive development of offspring, but limited information is available on its multigenerational reproductive toxicity. In our present study, zebrafish (Danio rerio) were exposed to BPS (1 and 100 μg/L) from 3 hpf to 120 dpf, and the effects on reproduction, sex steroid hormones, DNA methylation levels and gene transcription involved in steroidogenesis and DNA methylation were investigated in unexposed F1-2 offspring. The results showed that 100 μg/L BPS exposure increased DNA methylation in F1 testes, and 1 μg/L BPS led to DNA methylation in F2 ovaries. The increased DNA methylation levels led to decreased expression of steroidogenic enzymes, including cyp11a, cyp17 and 3βhsd, which might be a main reason for the elevated plasma 17β-estradiol and decreased testosterone levels. In addition, sex ratio indicated a female dominance trend, and reproductive capacity of male fish was severely impaired. Overall, these findings suggest that parental BPS exposure impairs reproductive development of unexposed offspring via DNA methylation and BPS-induced epigenetic modification inheritance has a long-term effect on the fitness and sustainability of fish populations.

DNA Methylation in Polycystic Ovary Syndrome：Emerging Evidence and Challenges

Polycystic ovary syndrome (PCOS) is a disease related to reproductive endocrine abnormalities in women of reproductive age, often accompanied by metabolic diseases such as hyperandrogenemia, insulin resistance and dyslipidemia. However, the etiology and mechanism of PCOS are still unclear. In recent years, more and more studies have found that epigenetic factors play an important role in PCOS. DNA methylation is the most widely studied epigenetic modification. At present, changes of DNA methylation have been found in serum, ovarian, hypothalamus, skeletal muscle, adipose tissue of PCOS patients, and these changes are closely related to insulin resistance, lipid metabolism and follicular development of PCOS. Although the current research on DNA methylation in PCOS is not in-depth, it indicated up a good direction for future research on the etiology and mechanism of PCOS. This review discussed the relationship between DNA methylation and PCOS. It is expected to help accelerate the application of DNA methylation in the diagnosis and treatment of PCOS.

Impact of Endocrine Disruptors upon Non-Genetic Inheritance

Similar to environmental factors, EDCs (endocrine-disrupting chemicals) can influence gene expression without modifying the DNA sequence. It is commonly accepted that the transgenerational inheritance of parentally acquired traits is conveyed by epigenetic alterations also known as "epimutations". DNA methylation, acetylation, histone modification, RNA-mediated effects and extracellular vesicle effects are the mechanisms that have been described so far to be responsible for these epimutations. They may lead to the transgenerational inheritance of diverse phenotypes in the progeny when they occur in the germ cells of an affected individual. While EDC-induced health effects have dramatically increased over the past decade, limited effects on sperm epigenetics have been described. However, there has been a gain of interest in this issue in recent years. The gametes (sperm and oocyte) represent targets for EDCs and thus a route for environmentally induced changes over several generations. This review aims at providing an overview of the epigenetic mechanisms that might be implicated in this transgenerational inheritance.

TET1 mediated male reproductive toxicity induced by Bisphenol A through Catsper-Ca2+ signaling pathway

Bisphenol A (BPA) exposure has many adverse effects on the reproductive system in animals and humans. Ten-eleven translocation 1 (TET1) is closely related to a variety of biological processes through regulating the dynamic balance of DNA demethylation and methylation. However, the role and mechanism of TET1 during BPA induced reproductive toxicity are largely unknown. In this study, mouse spermatogonia cell line GC-2 was treated with BPA in the final concentration of 0, 20, 40 and 80 μM for 72 h. The cell model of differential TET1 gene expression was established to explore the role and mechanism. We found that the growth rate of GC-2 cells, and the intracellular calcium level decreased significantly with the increase of BPA dose, while TET1 and Catsper1-4 expression level decrease with a dose-dependent relationship. Furthermore, TET1 overexpression promoted the proliferation of GC-2 cell, the increase of calcium ion concentration, and the expression level of Catsper1-4, while knockdown of TET1 leads to the opposite results. Mechanistically, TET1 expression promoted the hydroxymethylation of Catsper1-4 and reduced their methylation level. In addition, the expression level of Catsper1-4 was positively correlated with TET1 gene expression level in semen samples of the population. Our study revealed for the first time that TET1 gene regulates the expression of related molecules in the Catsper calcium signal pathway through its hydroxymethylation modification to affect the calcium level, thereby participating in the process of BPA induced damage. These results indicated that TET1 gene may be a potential biomarker of BPA induced male reproductive toxicity.

The effects of H22 tumor on the quality of oocytes and the development of early embryos from host mice: A single-cell RNA sequencing approach

The association between cancer and female reproduction remains largely unknown. Here we investigated the quality of oocytes and the developmental potential of zygotes using H22 tumor-bearing mice model. The results showed that the number of oocytes was decreased in tumor-bearing mice compared with the control mice, and accompanied scattered chromosomes was observed. Further study revealed an abnormal epigenetic reprogramming occurred in the zygotes from the H22 tumor-bearing mice, as exemplified by the aberrant 5hmC/5mC modifications in the pronuclei. Finally, single-cell RNA sequencing was performed on the oocytes collected from the H22 tumor-bearing mice. Our data showed that 45 of the 202 differentially expressed genes in tumor-bearing group were closely associated with oocyte quality. Protein interaction analysis indicated that the potential interaction among these 45 genes. Collectively, our study uncovered that the quality of oocytes and early embryonic development were affected by H22 tumor bearing via the altered expression patterns of genes related with reproduction, providing new insights into the reproductive capability of female cancer patients.

Glutathione protects against the meiotic defects of ovine oocytes induced by arsenic exposure via the inhibition of mitochondrial dysfunctions

Accumulating evidences revealed the connections between arsenic exposure and mitochondrial dysfunctions induced reproductive toxicology. Meanwhile, production declines were found in livestock suffering from arsenic exposure. However, the connections between arsenic exposure and livestock meiotic defects remain unclear. In this study, the effects of sodium arsenite (NaAsO2) exposure during the in vitro maturation (IVM) on the meiotic potentials of ovine oocytes were analyzed. Furthermore, the effects of glutathione (GSH) supplementation on the meiotic defects of NaAsO2 exposed ovine oocytes were investigated by the assay of nuclear maturation, spindle organization, chromosome alignment, cytoskeleton assembly, cortical granule (CGs) dynamics, mitochondrial dysfunctions, reactive oxygen species (ROS) accumulation, oxidative DNA damages, cellular apoptosis, epigenetic modifications and fertilization capacities. The results showed that the meiotic defects of NaAsO2 exposed ovine oocytes were effectively ameliorated by the GSH supplementation via the inhibition of mitochondrial dysfunctions, which not only promoted the nuclear maturation, spindle organization, chromosome alignment, cytoskeleton assembly, CGs dynamic and fertilization capacities, but also inhibited the ROS accumulation, oxidative DNA damages and apoptosis of ovine MII oocytes. The abnormal expressions of 5mC, H3K4me3 and H3K9me3 in NaAsO2 exposed ovine oocytes, indicating the abnormal epimutations of DNA methylation and histone methylation, were also effectively ameliorated by the GSH supplementation. Taken together, this study confirmed the connections between arsenic exposure and meiotic defects of ovine oocytes. Meanwhile, the effects of GSH supplementation on the developmental competence of livestock oocytes, especially for these suffering from arsenic exposure were also founded, benefiting the extended researches for the GSH applications.

New insights into bisphenols induced obesity in zebrafish (Danio rerio): Activation of cannabinoid receptor CB1

Bisphenols (BPs), as widely used plastic additives, penetrate into our daily lives. BPs are considered endocrine disruptors and could potentially induce obesity. In this study, the effects of bisphenol A (BPA) and tetrabromobisphenol A (TBBPA) on food intake and lipid metabolism in zebrafish were determined. Moreover, the impact of BPA and TBBPA on the endocannabinoid system (ECS) of zebrafish was further explored by metabolomics, transcriptomics, and molecular docking analysis. Here we show that exposure to BPA and TBBPA at concentrations commonly found in the environment (20, 100, and 500 μg/L) led to hyperphagia and obesity in adult male zebrafish. Metabolomics and histopathological analysis revealed significant lipid accumulation in the liver of zebrafish exposed to BPA and TBBPA. The expression of ECS-related genes, in conjunction with RNA-Seq results, further indicated that BPA and TBBPA increased appetite and induced obesity by activating cannabinoid receptor type 1(CB1). Furthermore, molecular docking revealed that six representative BPs including BPA and TBBPA could bind to the CB1 receptor. Collectively, these findings indicate that CB1 may be a potential target for BPs to induce obesity.

Effects of 2,4-dichlorophenol exposure on zebrafish: Implications for the sex hormone synthesis

2,4-Dichlorophenol (2,4-DCP), an estrogenic endocrine disruptor, is widely spread in aquatic environments and may interfere with normal physiological functions in fish. However, the influence of this chemical on the synthesis of sex hormones is not well understood. In the present study, zebrafish (Danio rerio) were exposed to 2,4-DCP (80 and 160 μg/L) with or without fadrozole (an aromatase inhibitor which inhibits the synthesis of estradiol) from 20 to 40 days post fertilization. Then, the sex ratio, the content of vitellogenin (VTG) and sex hormones (androstenedione (ASD), estrone (E1), 17β-estradiol (E2), estriol (E3), testosterone (T) and 11-ketotestosterone (11-KT)) were studied. Furthermore, the expression of genes involved in synthesis of sex hormones (cyp19a1a, cyp19a1b, 17β-hsd, 11β-hsd and cyp11b) along with the DNA methylation in cyp19a1a and cyp19a1b promoters was analyzed. The results showed that 2,4-DCP exposure led to female-biased ratio, increased the content of ASD, E2 and VTG, as well as the ratio of E2/11-KT, while decreased the levels of androgens (T and 11-KT). The sex hormonal change can be explained by the significant up-regulation of cyp19a1a, cyp19a1b, 17β-hsd and 11β-hsd genes. In addition, hypomethylation of cyp19a1a promoter was involved in this process. Notably, fadrozole can partly attenuate 2,4-DCP-induced feminization, and recover the levels of ASD, E2 and 11-KT. Thus, these results demonstrate that 2,4-DCP induces feminization in fish by disrupting the synthesis of sex hormones.

Role of Endocrine-Disrupting Chemicals in the Pathogenesis of Non-Alcoholic Fatty Liver Disease: A Comprehensive Review

Non-alcoholic fatty liver disease (NAFLD) is considered the most common liver disorder, affecting around 25% of the population worldwide. It is a complex disease spectrum, closely linked with other conditions such as obesity, insulin resistance, type 2 diabetes mellitus, and metabolic syndrome, which may increase liver-related mortality. In light of this, numerous efforts have been carried out in recent years in order to clarify its pathogenesis and create new prevention strategies. Currently, the essential role of environmental pollutants in NAFLD development is recognized. Particularly, endocrine-disrupting chemicals (EDCs) have a notable influence. EDCs can be classified as natural (phytoestrogens, genistein, and coumestrol) or synthetic, and the latter ones can be further subdivided into industrial (dioxins, polychlorinated biphenyls, and alkylphenols), agricultural (pesticides, insecticides, herbicides, and fungicides), residential (phthalates, polybrominated biphenyls, and bisphenol A), and pharmaceutical (parabens). Several experimental models have proposed a mechanism involving this group of substances with the disruption of hepatic metabolism, which promotes NAFLD. These include an imbalance between lipid influx/efflux in the liver, mitochondrial dysfunction, liver inflammation, and epigenetic reprogramming. It can be concluded that exposure to EDCs might play a crucial role in NAFLD initiation and evolution. However, further investigations supporting these effects in humans are required.