Xenoestrogens Research Articles

Transcriptome analysis reveals effects of ethynylestradiol and bisphenol A on multiple endocrine and metabolic pathways in the pituitary and liver of female Atlantic cod (Gadus morhua)

IntroductionThe pituitary and liver are among the main sites of action of estrogens in fish. Years of research has shown that xenoestrogens can interfere with functions of estrogens. There is however incomplete understanding of xenoestrogen targets genes, their molecular mechanisms and potential effects in some of the target organs, particularly the pituitary.MethodsWe performed a comprehensive analysis of pituitary and liver transcriptome 72 h after injection of ethynylestradiol (EE2: 10, 50 or 250 nmol/kg body weight/bw) and bisphenol A (BPA: 8, 40 or 200 μmol/kg bw) in juvenile female Atlantic cod (Gadus morhua).ResultsA broad range of reproductive and metabolic pathways were affected in both organs by BPA and EE2. In the pituitary, effects on the expression of many genes associated with reproduction-related hormonal pathways including the gonadotropin system, as well as genes in processes such as cell differentiation and metabolic homeostasis were observed. In the liver, in addition to upregulation of well-known estrogen marker genes, effects on metabolic pathways, in particular, a coordinated downregulation of genes in the triglyceride synthesis pathways were observed.DiscussionThe results suggest that estrogenic compounds affect a broad range of reproductive and metabolic processes in the pituitary. The alterations in the liver unravel the transcriptional changes underlying metabolic remodeling during estrogen induced vitellogenesis. This study provides new insights into mechanisms of endocrine and metabolic interactions that can be potential targets of environmental estrogens in fish. The study also identifies potential gene expression biomarkers for pituitary and liver effects of xenoestrogens.

Interaction of GPER-1 with the endocrine signaling axis in breast cancer

G Protein-Coupled Estrogen Receptor 1 (GPER-1) is a membrane estrogen receptor that has emerged as a key player in breast cancer development and progression. In addition to its direct influence on estrogen signaling, a crucial interaction between GPER-1 and the hypothalamic-pituitary-gonadal (HPG) axis has been evidenced. The novel and complex relationship between GPER-1 and HPG implies a hormonal regulation with important homeostatic effects on general organ development and reproductive tissues, but also on the pathophysiology of cancer, especially breast cancer. Recent research points to a great versatility of GPER-1, interacting with classical estrogen receptors and with signaling pathways related to inflammation. Importantly, through its activation by environmental and synthetic estrogens, GPER-1 is associated with hormone therapy resistance in breast cancer. These findings open new perspectives in the understanding of breast tumor development and raise the possibility of future applications in the design of more personalized and effective therapeutic approaches.

The role of lignin in 17β-estradiol biodegradation: insights from cellular characteristics and lipidomics

17β-estradiol (E2) is an endocrine disruptor, and even trace concentrations (ng/L) of environmental estrogen can interfere with the endocrine system of organisms. Lignin holds promise in enhancing the microbial degradation E2. However, the mechanisms by which lignin facilitates this process remain unclear, which is crucial for understanding complex environmental biodegradation in nature. In this study, we conducted a comprehensive analysis using cellular and lipidomics approaches to investigate the relationship between E2-degrading strain, Rhodococcus sp. RCBS9, and lignin. Our findings demonstrate that lignin significantly enhances E2 degradation efficiency, reaching 94.28% within 5 days with the addition of 0.25 mM lignin. This enhancement is associated with increased microbial growth and activity, reduced of membrane damages, and alleviation of oxidative stress. Fourier Transform Infrared Spectroscopy (FTIR) results indicate that lignin addition alters lipid peaks. Consequently, by analyzing lipid metabolism changes, we further elucidate how lignin addition promotes E2 degradation.

Preliminary Study on the Positive Expression Regulation of Alpha2-Macroglobulin in the Testicular Tissue of Male Mice by Environmental Estrogens.

The male reproductive impairment caused by environmental estrogens (EEs) stands as a pivotal research area in environmental toxicology. Alpha2-macroglobulin (A2M) emerges as a promising molecule capable of counteracting oxidative stress induced by EEs. This study conducted exposure experiments spanning PND1 to PND56 employing ICR mice, aiming to delve into the expression patterns of A2M and its modulated IL-6 in the testicular tissue of mice subsequent to diethylstilbestrol (DES) and benzophenone (BP) exposure, while elucidating the pivotal role of ERs in this intricate process. Our findings revealed that upon DES exposure (10 and 100 nM), there was a pronounced upregulation of A2M (mRNA and in situ protein levels) in mouse testicular tissue. Similarly, exposure to BPs (BP-1, BP-2, and BP-3, each at 10 and 1000 nM) exhibited comparable effects and increasing A2M levels in serum. Notably, BP exposure also caused an elevation in IL-6 levels (which could be directly regulated by A2M) within testicular tissue (mRNA and in situ protein). Remarkably, the specific estrogen receptor antagonist ICI 182780 (0.5 mg/kg/day) was effective in reversing the upregulation of both A2M and IL-6 induced by BP exposure. Significantly, the results of theoretical prediction of the potential ERE site in the A2m gene promoter region and ChIP-qPCR experiment provide essential and strong evidence for the key conclusion that A2m is the target gene of ER. Taken together, our study highlights EEs' ability to regulate A2M expression in the male reproductive system via the ER signaling pathway. This vital insight deepens our understanding of molecular mechanisms protecting against oxidative stress caused by EEs.

Fe(III)-Aided Novosphingobium sp. ES2-1 Regulates Molecular Mechanisms of 17β-Estradiol Biodegradation.

17β-estradiol (E2) is one of the strongest environmental estrogens threatening wildlife and human health globally. Microbial degradation is an alternative strategy to remediate E2-contaminated sites and may be regulated by ubiquitous Fe(III) in eco-environments. We have previously obtained a high-efficiency E2 degrader, Novosphingobium sp. ES2-1, and investigated its metabolic pathway in connection with monooxygenase EstO1-induced ring-B opening; however, the molecular mechanisms of ring-A cleavage in E2 are sorely lacking, especially under Fe(III)-aided regulation. Here, an extradiol dioxygenase EstN1 from strain ES2-1 involved in the ring-A cleavage of E2 was reported. It catalyzed the 4,5-seco reaction of 4-hydroxyestrone (4-OH-E1, a key E2-oxidized intermediate) with the support of the electron transport chain consisting of ferredoxin EstN2 and ferredoxin reductase EstN3, resulting in a ring-A meta-cleaved product. Interestingly, Fe(III)-assisted strain ES2-1 consolidated the opening of rings A and B in E2 by reinforcing the expression of estO1 and estN1 genes, consequently enhancing E2 metabolism. Compared to Fe(III) starvation, the biodegradation half-life of E2 was sharply reduced from 1.35 to 0.59 d after Fe(III) supplementation. Simultaneously, the transcription of estO1 and estN1 genes increased clearly from 4.3 to 47.5 times and 6.6 to 246.8 times after Fe(III) induction, respectively, accompanied by remarkable improvement in the abundance of ring-A/B cleavage products and their pyridine derivatives. These findings highlight the significance of Fe(III) in regulating the microbial remediation of environmental estrogens at the molecular level.

The Influence of Environmental Exposure to Xenoestrogens on the Risk of Cancer Development.

Xenoestrogens (XEs) are a group of exogenous substances that may interfere with the functioning of the endocrine system. They may mimic the function of estrogens, and their sources are plants, water or dust, plastic, chemical agents, and some drugs. Thus, people are highly exposed to their actions. Together with the development of industry, the number of XEs in our environment increases. They interact directly with estrogen receptors, disrupting the transmission of cellular signals. It is proven that XEs exhibit clinical application in e.g., menopause hormone therapy, but some studies observed that intense exposure to XEs leads to the progression of various cancers. Moreover, these substances exhibit the ability to cross the placental barrier, therefore, prenatal exposure may disturb fetus development. Due to the wide range of effects resulting from the biological activity of these substances, there is a need for this knowledge to be systematized. This review aims to comprehensively assess the environmental sources of XEs and their role in increasing cancer risk, focusing on current evidence of their biological and pathological impacts.

Bisphenol A-induced polycystic ovary syndrome (PCOS) with hormonal and metabolic implications in rats

There is a rising incidence of polycystic ovary syndrome (PCOS) cases worldwide in women of reproductive age due to environmental factors. We evaluated the effect of an environmental estrogen, bisphenol A (BPA) for its reprotoxicity regarding the induction of PCOS in rats and also assessed its hormonal and metabolic implications. There was 66.6 % and 50 % disorder, in the estrus cycle at low (50 µg/kg) and high (500 µg/kg) doses of BPA, respectively. While animals treated with the positive control (dehydroepiandrosterone, DHEA at 6 mg/100 g) caused 100 % disorder. Cystic and atretic follicles along with two corpora lutea were found in the low dose group. However, no corpus luteum was found in the high dose group. Furthermore, hyperplasia and hypertrophy were found in the myometrium, endometrium, and luminal epithelium of the uterus of the low dose and DHEA groups. Additionally, 17β estradiol, progesterone, DHEA, androstenedione, testosterone, dihydrotestosterone (DHT), dehydroepiandrosterone sulphate (DHEAS), antimullerian hormone (AMH), ratio of LH/FSH and testosterone/DHT were increased significantly (P < 0.01) in BPA groups. A significantly higher TSH (P < 0.01) indicates hypothyroidism. Furthermore, hyperglycemia, hyperinsulinemia, HOMA-IR, and HOMAβ indicate insulin resistance in the low-dose group. Thus, the low dose of BPA was found to be more potent as compared to the higher dose in defining the hyperandrogenic state. Our study revealed that BPA may not only be a causative factor in the induction of PCOS but also has metabolic implications bearing on its estrogenic nature.

“Study of the Measurement of Environmental Estrogen Level from Drinking Water in Dhaka City”- A Cross Sectional Study

“Study of the Measurement of Environmental Estrogen Level from Drinking Water in Dhaka City”- A Cross Sectional Study

Long-term exposure to environmentally relevant Bisphenol-A levels affects growth, swimming, condition factor, sex ratio and histology of juvenile zebrafish

Bisphenol A (BPA) is an environmental estrogen which perturbs hormone signaling pathways adversely affecting aquatic organisms. To evaluate the impact of developmental exposure to long term yet environmentally relevant low doses of BPA, wild-type juvenile zebrafish of 35 days post fertilization were treated with BPA (1 and 10 µg/L), treatment control (0.5% v/v methanol) and control for 60 days. Both BPA treatments led to significantly increased morality overtime. Length increment and specific growth rates became significantly high in BPA exposed zebrafish overtime. Obesogenic property of BPA was not evident with longexposure to low BPA doses. A significantly high and BPA dose-dependent female-biased sex ratios were observed following the juvenile exposure. Significantly low swimming speed was recorded in the fish of both BPA-treated tanks than that of control. Condition factor was significantly low in BPA exposed fish indicating the poor-wellness. There were numerous histopathological alterations of gonads, liver and kidney indicating impacts of juvenile exposure in zebrafish. Altered growth, swimming, mortality, feminization and histopathological changes in zebrafish induced by BPA indicate the risks associated with developmental exposures. The findings call for more comprehensive studies to comprehend the ecological risks imposed by low concentrations of environmental estrogens in urban aquatic ecosystems.

Vulnerable periods for the mouse mammary gland: Comparison of the effects of ethinyl estradiol exposures during two early stages of development

The mammary gland is responsive to endogenous hormones and environmental chemicals that are estrogen receptor (ER) agonists. The mouse mammary gland offers the opportunity to dissect the most sensitive windows of exposure. 17α-ethinyl estradiol (EE2) is a pharmaceutical ER agonist that often serves as a positive control for estrogen-active chemicals. Here, adult female mice were exposed to EE2 starting either at pregnancy day 7, or on lactational day 1, and exposures continued until the litters were weaned. The pups were therefore exposed during gestation + the juvenile period, or during the juvenile period alone. The morphology of the mammary gland was evaluated in both male and female offspring at two life stages: weaning (postnatal day [PND]21) and at puberty (PND32). Other hormone-sensitive outcomes evaluated included body weight, anogenital index, frequency of open vagina, and weight of the uterus. We found age- and sex-dependent effects of EE2 on these estrogen-responsive endpoints including the morphology of the mammary gland. Importantly, EE2 altered mammary gland morphology even when exposures were limited to the juvenile period. However, the number of endpoints that were affected in animals from the EE2-Juvenile-Only period were fewer, and typically of a lower magnitude, compared to those observed in the EE2-Gest-Juvenile group. Understanding the effects of environmental estrogen exposures during the juvenile period is critical because humans are exposed to estrogenic pollutants throughout life, including in early childhood.

Developing water quality and land use surrogates to predict endocrine-disrupting chemical profiles in a highly urbanized river basin

This study investigated geospatial distributions of endocrine-disrupting chemicals (EDCs) in the waters of the Dongjiang River and their associations with anthropogenic activities. Fifteen EDCs, with total concentrations in the river water of 149–2525 ng/L were detected, with bisphenol-A, 4-nonylphenol, 4-tert-octylphenol, p-hydroxybenzoic acid, and methylparaben being the five predominant EDCs. The total estrogen concentration was high downstream and significantly correlated with the spatial distribution of urban land use, wastewater discharge, population, and gross domestic product, indicating human activities have increased estrogen levels and threatened ecological health. The total risk quotient indicated a high ecological risk of estrogens to fish and a moderate to high ecological risk of personal care products to algae. Estrone, triclosan, bisphenol-A, 4-nonylphenol, and 4-tert-octylphenol were categorized as priority pollutants, which required special concern. Triclosan and triclocarban can serve as reliable chemical indicators for predicting EDC levels based on correlation analysis. The crucial factors affecting EDC levels were identified through the Mantel test and predictor importance was quantified using a multiple regression model, which can help predict occurrences and geospatial distributions of EDCs. Total phosphorus and electrical conductivity were the major predictors of EDC levels, providing promising indicators for monitoring EDCs in river water. Urban land proportion significantly affected phenolic environmental estrogens, natural estrogens, and disinfectants. In the main stream, urban population, urbanization rate, and gross domestic product influenced phenolic environmental estrogen levels. A mini-review of the global distribution of EDCs in river water revealed that income and population differences among countries affect their occurrence, suggesting socioeconomic factors should be considered to mitigate EDC pollution.

Estrogen receptor alpha mediated repression of PRICKLE1 destabilizes REST and promotes uterine fibroid pathogenesis.

Uterine fibroids (leiomyomas), benign tumors of the myometrial smooth muscle layer, are present in over 75% of women, often causing severe pain, menorrhagia and reproductive dysfunction. The molecular pathogenesis of fibroids is poorly understood. We previously showed that the loss of REST (RE-1 Silencing Transcription factor), a tumor suppressor, in fibroids leads to activation of PI3K/AKT-mTOR pathway. We report here a critical link between estrogen receptor alpha (ERα) and the loss of REST, via PRICKLE1. PRICKLE1 expression is markedly lower in leiomyomas, and the suppression of PRICKLE1 significantly down regulates REST protein levels. Conversely, overexpression of PRICKLE1 resulted in the restoration of REST in cultured primary leiomyoma smooth muscle cells (LSMCs). Crucially, mice exposed neonatally to environmental estrogens, proven risk factors for fibroids, expressed lower levels of PRICKLE1 and REST in the myometrium. Using mice that lack either endogenous estrogen (Lhb -/- mice) or ERα (Esr1 -/- mice), we demonstrate that Prickle1 expression in the myometrium is suppressed by estrogen through ERα. Enhancer of zeste homolog 2 (EZH2) is known to participate in the repression of specific ERα target genes. Uterine leiomyomas express increased levels of EZH2 that inversely correlate with the expression of PRICKLE1. Using chromatin immunoprecipitation, we provide evidence for association of EZH2 with the PRICKLE1 promoter and for hypermethylation of H3K27 within the regulatory region of PRICKLE1 in leiomyomas. Additionally, siRNA mediated knockdown of EZH2 leads to restoration of PRICKLE1 in LSMCs. Collectively, our results identify a novel link between estrogen exposure and PRICKLE1/REST-regulated tumorigenic pathways in leiomyomas.

Relationship Between Phenolic Environmental Estrogens and Gestational Diabetes Mellitus Modified by the Levels of One-Carbon Metabolism Nutrients in Chinese Pregnant Women

Relationship Between Phenolic Environmental Estrogens and Gestational Diabetes Mellitus Modified by the Levels of One-Carbon Metabolism Nutrients in Chinese Pregnant Women

Environmentally relevant estrogens impaired spermatogenesis and sexual behaviors in male and female zebrafish

Environmental estrogens (EEs) are found extensively in natural waters and negatively affect fish reproduction. Research on the reproductive toxicity of EEs mixtures in fish at environmentally relevant concentrations is scarce. In this study, adult male zebrafish were exposed for 60 days to EES (a mixture of EEs), EE2-low (5.55 ng/L, with an estrogenic potency equal to EES), and EE2-high (11.1 ng/L). After exposure, the expression levels of vtg1, vtg3, and esr1 in the livers in EES-treated fish remained unaltered, whereas they were significantly increased in EE2-treated fish. Both EE2-high and EES exposures notably reduced the gonad somatic index and sperm count. A disrupted spermatogenesis was also observed in the testes of EE2-high- and EES-exposed fish, along with an alteration in the expression of genes associated with spermatogonial proliferation (pcna, nanog), cell cycle transition (cyclinb1, cyclind1), and meiosis (aldh1a2, cyp26a1, sycp3). Both EE2 and EES significantly lowered plasma 11-ketotestosterone levels in males, likely by inhibiting the expression level of genes for its synthesis (scc, cyp17a1 and cyp11b2), and increased 17β-estradiol (E2) levels, possibly through upregulating the expression of cyp19a1a. A significant increase in tnfrsf1a expression and the tnfrsf1a/tnfrsf1b ratio in EE2-high and EES-treated males also suggests increased apoptosis via the extrinsic pathway. Further investigation showed that both EE2-high and EES diminished the sexual behavior of male fish, accompanied with reduced E2 levels in the brain and the expression of genes in the kisspeptin/gonadotropin-releasing hormone system. Interestingly, the sexual behavior of unexposed females paired with treated males was also reduced, indicating a synergistic effect. This study suggests that EES have a more severe impact on reproduction than EE2-low, and EEs could interfere not only with spermatogenesis in fish, but also with the sexual behaviors of both exposed males and their female partners, thereby leading to a more significant disruption in fish reproduction.

Asymmetric allostery in estrogen receptor-α homodimers drives responses to the ensemble of estrogens in the hormonal milieu

The estrogen receptor-α (ER) is thought to function only as a homodimer but responds to a variety of environmental, metazoan, and therapeutic estrogens at subsaturating doses, supporting binding mixtures of ligands as well as dimers that are only partially occupied. Here, we present a series of flexible ER ligands that bind to receptor dimers with individual ligand poses favoring distinct receptor conformations-receptor conformational heterodimers-mimicking the binding of two different ligands. Molecular dynamics simulations showed that the pairs of different ligand poses changed the correlated motion across the dimer interface to generate asymmetric communication between the dimer interface, the ligands, and the surface binding sites for epigenetic regulatory proteins. By examining the binding of the same ligand in crystal structures of ER in the agonist vs. antagonist conformers, we also showed that these allosteric signals are bidirectional. The receptor conformer can drive different ligand binding modes to support agonist vs. antagonist activity profiles, a revision of ligand binding theory that has focused on unidirectional signaling from the ligand to the coregulator binding site. We also observed differences in the allosteric signals between ligand and coregulator binding sites in the monomeric vs. dimeric receptor, and when bound by two different ligands, states that are physiologically relevant. Thus, ER conformational heterodimers integrate two different ligand-regulated activity profiles, representing different modes for ligand-dependent regulation of ER activity.

Induction of fibrosis following exposure to bisphenol A and its analogues in 3D human uterine leiomyoma cultures

Bisphenol A (BPA) and its analogues (BPAF, BPS) are ubiquitous environmental contaminants used as plastic additives in various daily life products, with many concerns on their role as environmental estrogens. Uterine leiomyomas (fibroids) are highly prevalent gynecologic tumors with progressive fibrosis. Fibroids are hormone-responsive and may be the target of environmental estrogens. However, the effects of BPA, BPAF, and BPS exposure on uterine fibrosis are largely unknown. Here, we evaluated fibrosis and the crucial role of TGF-beta signaling in human fibroid tumors, the profibrotic effects of BPA, BPAF or BPS in a human 3D uterine leiomyoma (ht-UtLM) in vitro model, and the long-term outcomes of BPAF exposure in rat uterus. In 3D ht-UtLM spheroids, BPA, BPAF, and BPS all promoted cell proliferation and fibrosis by increasing the production of extracellular matrices. Further mechanistic analysis showed the profibrotic effects were induced by TGF-beta signaling activation mainly through SMAD2/3 pathway and crosstalk with multiple non-SMAD pathways. Furthermore, the profibrotic effects of BPAF were supported by observation of uterine fibrosis in vivo in rats following long-term BPAF exposure. Overall, the 3D ht-UtLM spheroid can be an important model for investigating environment-induced fibrosis in uterine fibroids. BPA and its analogues can induce fibrosis via TGF-beta signaling.

Spatiotemporal variations and risk assessment of estrogens in the water of the southern Bohai Sea: A comprehensive investigation spanning three years

The ubiquitous and adverse effects of estrogens have aroused global concerns. Natural and synthetic estrogens in 255 water samples from the southern Bohai Sea were analyzed over three years. Total estrogen concentrations were 11.0–268 ng/L in river water and 1.98–99.7 ng/L in seawater, with bisphenol A (BPA) and 17α-ethynylestradiol (EE2) being the predominant estrogens, respectively. Estrogen showed the highest concentrations in summer 2018, followed by spring 2021 and spring 2019, which was consistent with the higher estrogen flux from rivers during summer. Higher estrogen concentrations in 2021 than in 2019 were driven by the higher level of BPA, an additive used in personal protective equipment. Estrogen exhibited higher concentrations in the southern coast of the Yellow River Delta and the northeastern coast of Laizhou bay due to the riverine input and aquaculture. Estrogens could disturb the normal endocrine activities of organisms and edict high ecological risks (90th simulated RQT > 1.0) to aquatic organisms, especially to fish. EE2 was the main contributor of estrogenic potency and ecological risk, which requires special concern. This is the first comprehensive study of estrogen spatiotemporal variations and risks in the Bohai Sea, providing insights into the environmental behavior of estrogens in coastal regions.

Xenoestrogens of anthropogenic origin in food products and their impact on human health

The anthropogenic impact on the biosphere has now acquired a global character, resulting in a massive influx of industrial, agricultural, and household waste into the environment. Numerous chemical, physical and biological substances present in the environment have a harmful effect on human health. Among them, a special group is formed by hormonally active xenobiotics – xenoestrogens. They are not produced by the body, but are structurally or functionally related to the human sex hormone 17β-estradiol, and bind to estrogen receptors with varying degrees of afnity and selectivity. The article summarizes and analyzes the available literature data on the most common synthetic xenoestrogens that can be present in foodstuff and have a negative impact on human health. In particular, such groups of substances as hormonal drugs, phenols, phthalates, pesticides, dioxins and dioxin-like substances, parabens, toxic metals are described. The presented evidence of the negative impact of synthetic xenoestrogens on human health requires more large-scale and clinically signifcant studies to determine the impact of chemical substances on the organs and systems of the human body, as well as generalization of the received evidence. Understanding the sources and extent of the impact of various xenobiotics on the environment and human health is essential for the development of comprehensive preventive measures. Key words: anthropogenic impact, xenoestrogens, toxicants, foodstuff, endocrine disorders.

Molecular mechanism of apoptosis induced by 4-tBP in common carp (Cyprinus carpio L.) head kidneys was explored from various angles: Hippo pathway, miR-203a, oxidative stress, ER stress, and mitochondrial pathway

4-tert butylphenol (4-tBP), a toxic environmental pollutant estrogen, received widespread attention due to its widespread presence, environmental persistence, and toxic effect. Common carp (Cyprinus carpio L.) is the most important freshwater economic animal in China and is also a model animal for the study on molecular mechanisms of poisoning. Head kidney is a target organ attacked by environmental pollutants. Here, we established a common carp 4-tBP poisoning model. The results showed that exposure to 4-tBP resulted in mitochondrial damage, endoplasmic reticulum damage, and apoptotic damage in head kidneys of common carps using microstructure and ultrastructure observations, as well as TUNEL kit methods. Furthermore, we found at transcriptional level from three perspectives that 4-tBP induced apoptosis in common carp head kidney cells: Hippo pathway, mitochondrial pathway, and ER stress. Hippo pathway formed a complex network, in which LATS1 was a core gene. It's noteworthy that Hippo pathway triggered mitochondrial pathway through YAP/NR4A1/Bcl-2 and YAP/BIRC5/Caspase-9 pathways under 4-tBP-induced apoptosis. PERK-eIF2α-ATF4-Caspase-3 pathway was involved in 4-tBP-induced apoptosis via ER stress. Moreover, miR-203a mediated 4-tBP-induced apoptosis through targeting MST1, MAP4K4, and NR4A1. In addition, 4-tBP disrupted balance between oxidants and antioxidants, and caused oxidative stress, and oxidative stress mediated ER stress under 4-tBP-caused apoptosis via via H2O2-PERK-eIF2α-ATF4-Caspase-3 pathway. miR-203a and oxidative stress participated in 4-tBP-induced apoptosis in common carp head kidney cells. For the first time, we found that Hippo pathway took part in molecular mechanism of fish poisoning, which needs to be investigated in the future. Our research provided foundational knowledge for exploring toxic effects of estrogen on fish and provided new insights into a theoretical basis for safety risk assessment for humans and fish, which deserves further profound exploration in the future. Moreover, the insights we generated help inform new strategies for preventing toxic injury in fish.

Comparison of in vitro Toxicities of 8-Prenylnaringenin, Tartrazine and 17β-Estradiol, Representatives of Natural and Synthetic Estrogens, in Rat and Human Hepatoma Cell Lines

ABSTRACT Background: Phytoestrogens have been praised for their beneficial health effects, whereas synthetic xenoestrogens have been connected to ailments. Aims: To ascertain whether the toxicities of natural and synthetic estrogens differ, we examined the potent phytoestrogen 8-prenylnaringenin (8-PN), the common synthetic xenoestrogen tartrazine, and the physiological estrogen 17β-estradiol (E2). Methods: These three compounds were tested for cytotoxicity, cell proliferation and genotoxicity in human HepG2 and rat H4IIE hepatoma cells. Results: All three estrogens elicited cytotoxicity at high concentrations in both cell lines. They also inhibited cell proliferation, with E2 being the most effective. They all tended to increase micronuclei formation. Conclusion: Natural estrogens were no less toxic than a synthetic one.