Characterization of Estrogenic and Androgenic Activities for Bisphenol A-like Chemicals (BPs): In Vitro Estrogen and Androgen Receptors Transcriptional Activation, Gene Regulation, and Binding Profiles

In utero exposure to estrogenic bisphenol analogues increases mammary tissue stiffness

In utero exposures to estrogenic endocrine disrupting compounds (EDCs) can increase breast cancer risk in adulthood. It has previously been shown that the estrogenic plasticizer bisphenol A (BPA) alters development of the mammary gland and increases both mammary gland stiffness and tumor susceptibility in rodent models following in utero exposure. Because of its endocrine disrupting properties, BPA has been substituted with structural analogues with varying abilities to activate estrogen receptor alpha (ERα). However, the impact of in utero exposure to many of these analogues is unknown. In the present study, we aimed to analyze the impact of bisphenol analogues on collagen deposition and mammary gland stiffness and characterize mammary epithelial development following exposure to these compounds. With the exception of bisphenol S, all analogues significantly increased mammary gland stiffness at a 25µg/kg body weight dose in a manner that correlated to estrogenic activity. In contrast, significant effects on epithelial development endpoints were limited and did not follow a clear pattern. These results add to the growing literature on the hazard of bisphenol analogues and support the idea that these compounds promote abnormal mammary gland development. Furthermore, these data support a model that bisphenol compounds induce a microenvironment that may promote breast cancer development in an estrogen-dependent manner.

Effects of multiple novel bisphenol S analogs on adipogenesis in 3T3-L1 cells

The increasing usage of bisphenol S (BPS) analogs as novel alternatives to bisphenol A (BPA) or BPS results in widespread exposure risks. In contrast to BPS, BPS analog-induced perturbations in lipid metabolism are largely unknown. Our study aimed to investigate the interactions of nine novel BPS analogs with peroxisome proliferator-activated receptor γ (PPARγ) and their impacts on 3T3-L1 adipogenesis. BPS and its analogs were found to have varying binding affinities to the PPARγ ligand-binding domain, and five of the BPS analogs were identified as novel PPARγ agonists as evidenced by increased expressions of the PPARγ mediated luciferase reporter gene. Interestingly, seven BPS analogs, including five BPS analogs with PPARγ agonistic potency and two BPS analogs with negligible binding affinity, exhibited comparable or even greater adipogenic effects than BPS, which were demonstrated by increased triglyceride accumulation and enhanced expressions of the adipogenic biomarkers in 3T3-L1 cells. Further comparison revealed that a phenoxy group may be a potential structural regulator for the adipogenic capacities of the test BPS analogs. The findings provided the first evidence that seven novel BPS analogs exerted adipogenic potentials through PPARγ or other signaling pathways, revealing a hidden environmental factor in the development of obesity and other lipid metabolism disorders.

Unravelling immunomodulatory effects of bisphenol A substitutes on human macrophages, T and B lymphocytes using in vitro models

This study investigates the immunomodulatory effects of BPA substitutes using in silico and in vitro approaches. A comprehensive in silico screening with Endocrine Disruptome of BPA and its 25 substitutes revealed that BPG, BPS-MAE, BPS-MPE, BPPH and PF201 have the highest potential to bind nuclear receptors. Based on the in silico ranking, 12 compounds were selected and tested in vitro to investigate their effects on THP-1 derived macrophages, Jurkat T cells and LCLs. The metabolic activity tests showed that BPA has IC50 values of 99-182 µM, while the values for BPG, BPPH and BPP are 5-10 times lower. Comparison of the IC50 values with the logP of the tested compounds showed that the BPA analogues affect cell viability in proportion to their lipophilicity (R2 = 0.9185). The results of the cytokine release assays showed that the BPA substitutes generally stimulated the proinflammatory response in THP-1 macrophages in a statistically significant manner when exposed to the environmentally relevant concentrations and suppressed it in the micromolar range in all cell lines tested. Further analysis using RamosBlue reporter cells indicated that BPAP, BPG, BPP and BPPH alter the NF-κB/AP-1 signalling pathway. Moreover, BPAP, BPG, BPP, BPPH, BPS-MAE, BPS-MPE, BTUM and PF201 were predicted in silico to be TLR4-MyD88 inhibitors. The overall results of this study identify BPG, BPP, BPPH, BPZ and TCBPA as BPA analogues with the highest immunomodulatory potential. In addition, the immunomodulatory potential of the BPA alternatives Pergafast201 and BTUM was confirmed in vitro for the first time. This study emphasises the need for cautious evaluation of BPA substitutes due to their potential immunomodulatory effect, which could significantly affect public health.

Perinatal exposure to 4-hydroxy-4'-isopropoxydiphenylsulfone alters the adipogenesis in adult mice: A sex-specific study

4-hydroxy-4'-isopropoxydiphenylsulfone (BPSIP), a common alternative to bisphenol A (BPA), has been detected in breast milk and across placental barriers. However, the long-term impacts of perinatal exposure to BPSIP on adipogenesis and susceptibility to metabolic disorders later in life remain poorly understood. This study explored the effects of early-life BPSIP exposure on obesity and metabolic dysfunction in a diet-induced obesity model. Pregnant ICR mice were administered with BPSIP via oral gavage at doses of 0.02, 0.1, and 0.5 mg/kg body weight/day from gestational day 6 to postnatal day 21. After weaning, male and female offspring from control and high dose groups were fed either a normal diet (ND) or a high-fat diet (HFD) for 6 weeks. Results showed that perinatal BPSIP exposure significantly increased serum cholesterol levels, parametrial white adipose tissue (pWAT) weight, and body weight in female offspring, whereas males exhibited the opposite trend. Gene expression analyses revealed sex-specific alterations in adipogenesis, lipid metabolism, and endocrine function within pWAT, with these effects being more pronounced in HFD-fed BPSIP-exposed offspring. These findings demonstrate that perinatal exposure to BPSIP disrupts lipid metabolism in a sex-dependent manner, underscoring the potential long-term metabolic risks associated with BPSIP exposure during critical developmental periods.

Bisphenol Z inhibits the function of Leydig cells via upregulation of METTL3 expression in adult male rats

The use of bisphenol A has been restricted due to its toxicity. However, the impact of its substitute, bisphenol Z (BPZ), on Leydig cell function remains uncertain. We aimed to examine the associations between BPZ exposure and the disruption of Leydig cell function via upregulating Mettl3 and inducing oxidative stress. To address this, in vivo, male adult Sprague-Dawley rats received BPZ (0, 1, 10, or 100mg/kg/d orally) for 7 days, and in vitro, purified Leydig cells were treated with BPZ (0-20μM, 24h). Leydig cell morphology and function were assessed. The results showed that BPZ did not alter Leydig cell quantity but notably decreased serum testosterone levels. Furthermore, it significantly downregulated the expression levels of genes and proteins (SCARB1, STAR, CYP17A1, HSD17B3, and INSL3) in Leydig cells. Concurrently, BPZ treatment led to diminished expression of antioxidant genes (Gpx1 and Cat), an upregulation in m6A related gene (Mettl3) subsequent to the enrichment of RNA methylation fragments in the testis. In vitro analysis of primary Leydig cells demonstrated that BPZ heightened oxidative stress and diminished testosterone production. In conclusion, BPZ reduces rat testosterone by downregulating steroidogenic genes (Star, Scarb1, Cyp17a1, and Hsd17b3) via METTL3-m6A-Camkk2 pathway, impairing Leydig cell function.

The environmental occurrence, human exposure, and toxicity of novel bisphenol S derivatives: A review

Novel bisphenol S (BPS) derivatives are being increasingly utilized as substitutes to bisphenol A (BPA) and BPS in thermal receipts and other industrial or commercial products. In recent years, the environmental occurrence, human exposure, and toxicity of non-chlorinated and chlorinated BPS derivatives have been investigated in numerous studies. This review summarizes the state-of-art and new knowledge on these aspects and provides recommendations for future research directions. The environmental analysis showed that BPS derivatives have been widely detected in paper products, water, indoor dust, sediment, and municipal sewage sludge. Recent studies have also reported the presence of non-chlorinated BPS derivatives, such as benzenesulfonylbenzene (DDS) and 4-(4-propan-2-yloxyphenyl)sulfonylphenol (BPSIP), in human breast milk, urine, and the maternal-fetal-placental unit. Toxicological studies suggest that BPS derivatives may cause a series of toxic effects, including endocrine-disrupting effects, cytotoxicity, hepatotoxicity, developmental toxicity, and neurotoxicity, some of which have been shown to exhibit adverse effects similar to or even greater than those of BPS. Future studies should focus on elucidating environmental occurrences, half-lives, sources for human exposure, and potential transformation pathways of BPS derivatives, as well as their toxic effects and underlying mechanisms.

Bisphenol A Exposure Modifies the Vasoactive Response of the Middle Cerebral Artery

Bisphenol A (BPA) is the most used widely synthetic compound for the manufacture of polycarbonate plastics and epoxy resins produced worldwide. Given its androgenic and estrogenic activities, BPA is an endocrine disruptor that is linked to neurological and vascular outcomes, including strokes. Therefore, this study aims to investigate the mechanisms by which a 24 h exposure to BPA (0.002-20 μM) modifies the contractile function of rat middle cerebral artery (MCA) smooth muscle cells (SMCs). Thus, MCA explants were isolated from Wistar rats, and the SMC-MCA vasoactive response was assessed using planar cell surface area, while the gene expression of proteins and ion channel subunits involved in the MCA vasoactive response was evaluated by real-time quantitative PCR. The exposure to BPA (0.02 and 2 μM) decreased the noradrenaline (NA) vasocontractile response and sodium nitroprusside (SNP) vasorelaxant response. Moreover, exposure to BPA (0.02 and 2 μM) increased the gene expression of the soluble guanyl cyclase protein and the large conductance Ca2+-activated K+ channels (1.1 α-subunit). These results suggest an impairment of the SMC-MCA vasoactive response induced by intermediate BPA concentrations, an effect not attained for the lowest or highest exposure concentrations (non-monotonic inverted U-shaped response). In summary, these findings suggest that BPA exposure modifies MCA vascular homeostasis by interfering with the nitric oxide (NO) pathway and may, thus, be involved in ischemic stroke development.

The obesogenic effects of Bisphenol A and its analogues are differentially regulated via PPARγ transactivation in mouse 3T3-L1 cells

Exposure to environmental pollutants with obesogenic activity is being recognised as one of the contributing factors to the obesity epidemic. Bisphenol A (BPA) has been shown to stimulate adipogenesis in both human and mouse preadipocytes, to increase body weight and affect lipid metabolism in animal and epidemiological studies. Regulatory action and public concern has prompted industry to replace BPA with other structurally similar analogues that may have similar effects. In this study we investigated the effects of fifteen BPA analogues on adipogenesis in the mouse 3 T3-L1 pre-adipocyte cell model in order to determine their adipogenic activity relative to BPA. 3 T3-L1 cells were treated with increasing concentrations of BPA and replacements and mRNA expression of the mature adipocyte markers fatty acid binding protein 4 (Fabp4), perilipin (Plin) lipoprotein lipase (Lpl)and peroxisome proliferator-activated receptor (Ppar)γ and lipid accumulation were assessed. In addition, a luciferase reporter assay for PPARγ transactivation was employed to investigate mechanism of action. Our results show that BPC, BPS-MAE, BPS-MPE and TGSA, were the most adipogenic bisphenols, as shown by a robust increase in lipid accumulation and mRNA expression of adipogenic markers. BPS-MPE, BPC, BTUM, TGSA and D8 increased PPARγ transcriptional activity. Despite its ability to activate PPARγ in the transcriptional assay D8 did not affect adipogenesis in this cell model.

Comprehensive assessment of the safety of bisphenol A and its analogs based on multi-toxicity tests in vitro

As substitutes for bisphenol A (BPA), bisphenol analogs (BPs) have raised concerns due to their frequent environmental detection and unclear safety. Here, the cytotoxicity, endocrine disruption, neurotoxicity, aryl hydrocarbon receptor (AhR) activity, and genotoxicity of nine BPs and BPA were evaluated in three types of cell lines. Over half of the tested BPs exhibited greater cytotoxicity than BPA, with IC50 values showing a linear correlation with LogKow (R²=0.69). All tested BPs exhibited at least one endocrine-disrupting effect, notably estrogenic, which was observable even at 0.01-0.1 μM. Importantly, BPAF and BPAP exposure had widespread endocrine-suppressing effects. Moreover, all BPs (except BPP) and BPA increased SH-SY5Y cells apoptosis at 1-10 μM. Only BPF and BPP significantly increased 7-ethoxyresorufin-O-deethylase levels, highlighting their notable effects on AhR activity. BPAF significantly induced DNA damage at 1.25 μM, whereas BPA, BPF, and BPP induced damage at 20, 25, and 25 μM, respectively. Finally, ToxPi, a weighted scoring system, was used to rank the comprehensive toxicity of BPs, with 7 of 9 BPs showing higher scores than BPA. Collectively, BPs generally exhibited stronger comprehensive toxicity compared with BPA, emphasizing the urgent need for further research to confirm their potential health implications.

The biological effects of bisphenol AF in reproduction and development: What do we know so far?

Due to the established endocrine-disrupting effects of Bisphenol A (BPA), alternative bisphenols entered the market. Bisphenol AF (BPAF) is now commonly used in the industrial manufacturing of polycarbonate plastics and epoxy resins. However, BPAF's effects on reproduction and development have not been thoroughly reviewed. We investigated the relationship between BPAF exposure and reproduction and early development. We performed a literature review of studies on BPAF and reproductive physiology. Using keywords, we searched PubMed, Medline, Cochrane Library Database, Embase, and ClinicalTrials.gov for English language literature available until December 2024; we additionally identified and included studies from bibliographies. We included 125 articles, spanning in vitro and in vivo model organism and human studies. BPAF is a selective estrogen receptor modulator and an androgen receptor antagonist and is more potent than BPA. It is detected in urine, blood products, saliva, amniotic fluid, and breast milk. In vitro and in vivo studies demonstrate a spectrum of BPAF-induced endocrine and reproductive changes in both sexes. There is strong evidence of alterations in the hypothalamic-pituitary-gonadal axis and of altered steroidogenesis pathways. Multiple studies using zebrafish, Xenopus, chickens, and rodents, show BPAF's effects on embryogenesis, morphology, and sexual differentiation. Decreased serum testosterone and impaired spermatogenesis and oocyte viability have been demonstrated. The current literature shows clear disruptive effects of BPAF on reproductive health and embryonic development. Though further investigation is warranted, there is ample converging evidence to support limiting the use of BPAF and other similar bisphenols.

The Ovary as a Target Organ for New Generation Bisphenols Toxicity

Bisphenols (BPs) are a group of organic compounds used extensively in plastics, coatings, and epoxy resins; they have been of concern recently due to their endocrine-disrupting effects. Among these, bisphenol A (BPA) is the most studied. Regulatory measures, such as the ban on BPA use in baby bottles by the European Union and its restricted use in thermal paper, reflect the growing awareness of the health risks of BPA. To mitigate these risks, analogs such as bisphenol S (BPS), bisphenol F (BPF), and others (BPAF, BPAP, BPB, BPP, BPZ) have been developed as alternatives. Despite their intended safety, these analogs have been detected in environmental media, including indoor dust and thermal receipt paper, as well as in human biological samples. Studies report their presence in urine at levels comparable to BPA, with BPS and BPF found in 78% and 55% of samples, respectively. In addition, BPs have been found in human follicular fluid (FF) at concentrations that could exert some paracrine effects on ovarian function and reproductive health. With the increased global production of BPs, occupational exposure and environmental contamination also increase. This review summarizes what is currently known about the effects of BPs on the ovary and the mechanisms by which PBs exert ovarian toxicity, with a particular focus on oogenesis, folliculogenesis, and steroidogenesis. Further, this review emphasizes their influence on reproductive functions and the need for further biosafety evaluations.

2,4-Bisphenol S triggers physiological changes, oxidative stress and lipidome alterations in Gram-positive Enterococcus faecalis at environmental concentrations

2,4-bisphenol S (2,4-BPS) was an emerging BPS analogue as color developers, widely found in the environment. Fish toxicities, cytotoxicity and antiestrogenic effects of 2,4-BPS have been documented at mg L-1, while the toxicity of 2,4-BPS at environmental concentrations (from ng L-1 to μg L-1) were scarce. Bacteria are identified as important components of the ecosystem, while little is known regarding the ecotoxicity of 2,4-BPS on bacteria. Enterococcus faecalis, a good indicator of faecal contamination and anthropogenic pollution, was exposed to 0.5-50 nmol L-1 2,4-BPS. 2,4-BPS resulted in significantly decreased growth but notably increased membrane permeability in E. faecalis compared with the control. Hormetic effects on the expression of genes involved in DNA replication and efflux were observed. Inhibition of biofilm formation and induction of oxidative stress were caused by 0.5, 5 and 50 nmol L-1 2,4-BPS. Fatty acyls, glycerolipids and glycerophospholipids were differentially regulated by 2,4-BPS. Glycerolipid metabolism and glycine, serine and threonine metabolism were significantly altered by 0.5 nmol L-1 2,4-BPS, compared with glycerophospholipid metabolism disturbed by 5 and 50 nmol L-1 2,4-BPS, showing concentration-dependent responses. Trend analysis of differential lipids demonstrated that there were three significant clusters, all of which were enriched in glycerophospholipid metabolism. 2,4-BPS elicited the strongest lipidomic responses at 5 nmol L-1. Our study provides evidence for 2,4-BPS-induced toxicity to E. faecalis at environmental concentrations and contributes to a comprehensive understanding of the interaction between 2,4-BPS and Gram-positive bacteria.

BPAP induces autism-like behavior by affecting the expression of neurodevelopmental genes in Drosophila melanogaster

Bisphenol AP (BPAP), an environmental endocrine disruptor, may cause neurodevelopmental disorders affecting human health. Studies have shown that BPAP impacts hormone synthesis and metabolism, causes social behavior abnormalities, and induces anxiety-like behavioral impairments in mice. However, evidence for the neurobehavioral effects of BPAP is still lacking. Here, we examined the toxic effects of BPAP on neurodevelopment using a Drosophila model. We assessed the role of BPAP exposure in autism-like behavior and explored the underlying mechanisms. Our findings indicated that BPAP exposure reduced pupation and eclosion rates and delayed growth in Drosophila. Furthermore, BPAP exposure caused autism-like behaviors, characterized by increased grooming times and aberrant social interactions, along with abnormalities in locomotor activity, as well as learning and memory ability. Mechanistically, we found that BPAP decreases the number of neuroblasts (NBs) and mature intermediate neural progenitors (INPs) in the 3rd larval brain, impairing axon guidance in the mushroom body of the adult Drosophila brain. Additionally, our transcriptome analysis revealed that BPAP exposure alters the expression of neurodevelopment-related genes (Nplp3, sand, lush, and orco) and affects the estrogen signaling pathway (Hsp70Ab, Hsp70Bc, Hsp70Ba, and Hsp70Bb). These changes potentially explain the BPAP-induced autism-like behavior in Drosophila.

Urinary profiles of bisphenol S derivatives and their exposure pathway analysis in maternal and infant populations of Beijing

Bisphenol S (BPS) derivatives have potential reproductive developmental toxicity and have been found in the environment and in breast milk. The level of infant exposure and the source are currently unknown. In this study, we investigated BPS and six derivatives (together referred to as BPs) in urine samples from mothers and infants, indoor dust, breast milk and infant formula in Beijing, China. BPS, diphenyl sulfone (DPS) and 4-allyloxy-4'-hydroxydiphenyl sulfone (BPS-MAE) were the main BPs. Notably, the concentration of DPS in infants' urine was higher than that of BPS, which warrants attention. Infants have higher daily intake levels than mothers. Exclusively breastfed infants have a higher risk of BPs exposure than exclusively formula-fed infants. For exclusive breastfed infants, the contribution of individual BPs through breast milk was 23.2% to 93.6%. While for exclusively formula-fed infants, the contribution of individual BPs through infant formula was 30.5% to 70.3%. The contribution of individual BPs through indoor dust was no more than 10%. The results suggesting that infants can be exposed to BPs through other pathways. This is the first comprehensive assessment of maternal and infants exposure to BPS derivatives, providing insights into the sources of infant exposure.

Reducing Exposures to Endocrine Disruptors (REED) study, a personalized at-home intervention program to reduce exposure to endocrine disrupting chemicals among a child-bearing age cohort: study protocol for a randomized controlled trial

BACKGROUND

Exposures to endocrine disrupting chemicals (EDCs) have been linked to chronic diseases including breast cancer, metabolic syndrome, diabetes, and infertility. Exposure during pregnancy may have a lifelong impact on the fetus. Services are needed to allow individuals to learn about their personal EDC exposures and how to reduce them. Million Marker (MM) aims to crowdsource and scale the biomonitoring of environmental chemicals and provide actionable results to empower individuals to proactively assess, track, and reduce their EDC exposures. In previous research, we developed and tested the first mobile EDC intervention service (mail-in urine testing and exposure report-back) for its efficacy in increasing EH literacy (EHL), willingness to reduce exposures (i.e., readiness to change, RtC), and system usability. After intervention, we found increased EHL, increased RtC in women (but not men), and decreased EDC exposure. However, some participants did not increase their RtC and had difficulty carrying out the intervention on their own. The reasons for these less optimal results were the difficulty in the EHL subject matter-participants still felt ill-prepared to apply their knowledge to making healthier lifestyle changes. Therefore, in this study, we will address these perceived limitations.

METHODS

We will test a self-directed online interactive curriculum with live counseling sessions and individualized support modeled after the highly effective Diabetes Prevention Program (DPP). Recruiting from the Healthy Nevada Project (HNP), one of the largest population health cohorts in the world, we test the effectiveness of our EDC-specific online intervention curriculum via EHL and RtC surveys and determine changes in EDC exposure before and after intervention in a randomized controlled trial. We will also test for common clinical biomarkers via a commercially available at-home test (Siphox). We will recruit and randomize 300 women and 300 men of reproductive age (total n=600) from HNP. Our target population is men and women of reproductive age (18-44 years old).

DISCUSSION

At the conclusion of this project, we will be well-positioned to scale our services to clinics and the general public, with the eventual aims of FDA approval, insurance coverage, and incorporation into routine clinical care.

Metabolic status is a key factor influencing proteomic changes in ewe granulosa cells induced by chronic BPS exposure

BACKGROUND

Bisphenol S (BPS) is the main substitute for bisphenol A (BPA), a well-known plasticiser and endocrine disruptor. BPS disrupts ovarian function in several species. Moreover, a few studies have reported that the effects of BPS might be modulated by the metabolic status, and none have characterised the granulosa cell (GC) proteome after chronic BPS exposure.

OBJECTIVES

This study aimed to decipher the mechanisms of action of chronic BPS exposure on the proteome of ewe GCs while considering the interaction between a deliberate contrasted metabolism and reproductive function.

METHODS

Forty ewes were split into two groups with contrasted diets: restricted (R, n = 20) and well-fed (WF, n = 20). The R and WF ewes were subdivided according to the dose of BPS administered through the diet (0-50 µg/kg/day), forming four groups: R0, R50, WF0 and WF50. After 3-month BPS daily exposure, GCs were recovered during the pre-ovulatory stage and proteins were analysed by nano-liquid chromatography coupled with tandem mass spectrometry.

RESULTS

Chronic exposure to BPS affected the GC proteome differently according to the ewe metabolic status. Fifty-nine out of 958 quantified proteins were differentially abundant between groups and are mainly involved in carbohydrate and lipid pathways. Unsupervised hierarchical clustering of differentially abundant proteins (DAPs) identified four clusters of 34, 6, 5 and 14 proteins according to the BPS exposure and diet interaction. Pairwise comparisons between groups also revealed a strong effect of BPS exposure and diet interaction. Functional analysis of DAPs highlighted that BPS upregulated β-glucuronidase (GUSB; p = 0.002), a protein especially able to deconjugate bisphenol glucuronides (BP-g). Moreover, among unexposed ewes, GUSB was detected only in well-fed ewes.

DISCUSSION

Conjugation of glucuronides inhibits the oestrogenic activity of bisphenols. Upregulation of GUSB in ewes dosed with BPS would prolong the oestrogenic effects of BPS by deconjugating BPS-g into free BPS. In addition, literature has reported an up-regulation of GUSB in people suffering from obesity. Therefore, people suffering from obesity could be subjected to prolonged and aggravated exposure to BPS. These data highlighted the deleterious effects of BPS and its interaction with metabolic status.

Developmental exposures to common environmental pollutants result in long-term Reprogramming of hypothalamic-pituitary axis in mice

Humans are exposed to a range of endocrine disrupting chemicals (EDCs). Many studies demonstrate that exposures to EDCs during critical windows of development can permanently affect endocrine health outcomes. Most experimental studies address changes in secretion of hormones produced by gonads, thyroid gland and adrenals, and little is known about the ability of EDCs to produce long-term changes in the hypothalamic-pituitary (HP) control axes. Here, we examined the long-term effects of three common EDCs on male mouse HP gene expression, following developmental exposures. Pregnant mice were exposed to 0.2 mg/ml solutions of bisphenol S (BPS), 2,2',4,4'-tetrabromodiphenyl ether (BDE-47), or 3,3',5,5'-tetrabromobisphenol A (TBBPA) from pregnancy day 8 through lactation day 21 (weaning day). Male offspring were left untreated until postnatal day 140, where pituitaries and hypothalami were collected. Pituitaries were assed for gene expression via RNA sequencing, while specific genes were assessed for expression in hypothalami via RT-qPCR. Differential expression, as well as gene enrichment and pathway analysis, indicated that all three chemicals induced long-term changes, (mostly suppression) in pituitary genes involved in its endocrine function. BPS and BDE-47 produced effects overlapping significantly at the level of effected genes and pathways. All three chemicals altered pathways of gonad and liver HP axes, while BPS altered HP-adrenal and BDE-47 altered HP-thyroid pathways specifically. All three chemicals reduced expression of immune genes in the pituitaries. Targeted gene expression in the hypothalamus indicates down regulation of hypothalamic endocrine control genes by BPS and BDE-47 groups, concordant with changes in the pituitary, suggesting that these chemicals suppress overall HP endocrine function. Interestingly, all three chemicals altered pituitary genes of GPCR-mediated intracellular signaling molecules, key signalers common to many pituitary responses to hormones. The results of this study show that developmental exposures to common EDCs have long-term impacts on hormonal feedback control at the hypothalamic-pituitary level.

High-throughput transcriptomics toxicity assessment of eleven data-poor bisphenol A alternatives

Bisphenol A (BPA), a widely used chemical in the production of plastics and epoxy resins, has garnered significant attention due to its association with adverse health effects, particularly its endocrine-disrupting properties. Regulatory measures aimed at reducing human exposure to BPA have led to a proliferation of alternative chemicals used in various consumer and industrial products. While these alternatives serve to reduce BPA exposure, concerns have arisen regarding their safety and potential toxicity as regrettable substitutes. Previous efforts have demonstrated that in vitro high-throughput transcriptomics (HTTr) studies can be used to assess the endocrine-disrupting potential of BPA alternatives, and this strategy produces transcriptomic points-of-departure (tPODs) that are protective of human health when compared to the PODs from traditional rodent studies. In this study, we used in vitro HTTr to assess the potential for toxicity of eleven data-poor legacy chemicals sharing structural similarities to BPA. Human breast cancer MCF-7 cells were exposed to BPA and 11 alternatives at concentrations ranging from 0.1 to 25 μM to assess toxicity. Analysis of global transcriptomic changes and a previously characterized estrogen receptor alpha (ERα) transcriptomic biomarker signature revealed that 9 of 11 chemicals altered gene expression relative to controls. One of the chemicals (2,4'-Bisphenol A) activated the ERα biomarker at the same concentration as BPA (i.e., 4,4'-BPA) but was deemed to be more potent as it induced global transcriptomic changes at lower concentrations. These results address data gaps in support of ongoing screening assessments to identify BPA alternatives with hazard potential and help to identify potential candidates that may serve as safer alternatives.

Signature analysis of high-throughput transcriptomics screening data for mechanistic inference and chemical grouping

High-throughput transcriptomics (HTTr) uses gene expression profiling to characterize the biological activity of chemicals in in vitro cell-based test systems. As an extension of a previous study testing 44 chemicals, HTTr was used to screen an additional 1,751 unique chemicals from the EPA's ToxCast collection in MCF7 cells using 8 concentrations and an exposure duration of 6 h. We hypothesized that concentration-response modeling of signature scores could be used to identify putative molecular targets and cluster chemicals with similar bioactivity. Clustering and enrichment analyses were conducted based on signature catalog annotations and ToxPrint chemotypes to facilitate molecular target prediction and grouping of chemicals with similar bioactivity profiles. Enrichment analysis based on signature catalog annotation identified known mechanisms of action (MeOAs) associated with well-studied chemicals and generated putative MeOAs for other active chemicals. Chemicals with predicted MeOAs included those targeting estrogen receptor (ER), glucocorticoid receptor (GR), retinoic acid receptor (RAR), the NRF2/KEAP/ARE pathway, AP-1 activation, and others. Using reference chemicals for ER modulation, the study demonstrated that HTTr in MCF7 cells was able to stratify chemicals in terms of agonist potency, distinguish ER agonists from antagonists, and cluster chemicals with similar activities as predicted by the ToxCast ER Pathway model. Uniform manifold approximation and projection (UMAP) embedding of signature-level results identified novel ER modulators with no ToxCast ER Pathway model predictions. Finally, UMAP combined with ToxPrint chemotype enrichment was used to explore the biological activity of structurally related chemicals. The study demonstrates that HTTr can be used to inform chemical risk assessment by determining in vitro points of departure, predicting chemicals' MeOA and grouping chemicals with similar bioactivity profiles.

A critical review to identify data gaps and improve risk assessment of bisphenol A alternatives for human health

Bisphenol A (BPA), a synthetic chemical widely used in the production of polycarbonate plastic and epoxy resins, has been associated with a variety of adverse effects in humans including metabolic, immunological, reproductive, and neurodevelopmental effects, raising concern about its health impact. In the EU, it has been classified as toxic to reproduction and as an endocrine disruptor and was thus included in the candidate list of substances of very high concern (SVHC). On this basis, its use has been banned or restricted in some products. As a consequence, industries turned to bisphenol alternatives, such as bisphenol S (BPS) and bisphenol F (BPF), which are now found in various consumer products, as well as in human matrices at a global scale. However, due to their toxicity, these two bisphenols are in the process of being regulated. Other BPA alternatives, whose potential toxicity remains largely unknown due to a knowledge gap, have also started to be used in manufacturing processes. The gradual restriction of the use of BPA underscores the importance of understanding the potential risks associated with its alternatives to avoid regrettable substitutions. This review aims to summarize the current knowledge on the potential hazards related to BPA alternatives prioritized by European Regulatory Agencies based on their regulatory relevance and selected to be studied under the European Partnership for the Assessment of Risks from Chemicals (PARC): BPE, BPAP, BPP, BPZ, BPS-MAE, and TCBPA. The focus is on data related to toxicokinetic, endocrine disruption, immunotoxicity, developmental neurotoxicity, and genotoxicity/carcinogenicity, which were considered the most relevant endpoints to assess the hazard related to those substances. The goal here is to identify the data gaps in BPA alternatives toxicology and hence formulate the future directions that will be taken in the frame of the PARC project, which seeks also to enhance chemical risk assessment methodologies using new approach methodologies (NAMs).

Occurrence of bisphenol A analogues in the aquatic environment and their behaviors and toxicity effects in plants

Continuous technological and economic development has led to the extensive use of bisphenol A analogues (BPs) in products, leading to their release to aquatic environments and posing threats to aquatic plants. However, few papers have systemically reviewed the interactions between BPs and aquatic plants. This review comprehensively summarizes the properties, occurrence, fate, and hazardous influences of BPs on aquatic plants. BPs have been widely detected in the global aquatic environment, with concentrations generally ranging from a lower range of ng/L or ng/g to an upper range of μg/L or μg/g in surface water, groundwater, seawater, and sediments. Aquatic plants effectively uptake and translocate BPs, and metabolize them into new compounds. Meanwhile, BPs exposures have diverse toxic effects on the growth, photosynthesis, antioxidant, phytohormones, and structural integrity of aquatic plants. High-throughput omics assays provide significant evidence showing how BPs disturb gene transcription, proteins, and metabolism in plants. This review highlights the need for increased attention on the effects of emerging BPA alternatives, joint treatment, long-term exposure with environmental relevant doses, and potential hazards posed by ingesting polluted plants.

Mitigating Dietary Bisphenol Exposure Through the Gut Microbiota: The Role of Next-Generation Probiotics in Bacterial Detoxification

Bisphenols, such as bisphenol A and its analogs, which include bisphenol S, bisphenol F, bisphenol AF, and tetramethyl bisphenol F, are chemical contaminants commonly found in food that raise serious health concerns. These xenobiotics can potentially have harmful effects on human health. The gut microbiota plays a crucial role in metabolizing and neutralizing these substances, which is essential for their detoxification and elimination. Probiotic supplementation has been studied for its ability to modulate the gut microbiota's composition and function, enhancing detoxification processes. Next-Generation Probiotics (NGPs) may exhibit better properties than traditional strains and are designed for targeted action on specific conditions, such as obesity. By modulating inflammatory responses and reducing the secretion of pro-inflammatory cytokines, they can significantly improve host health. Research on NGPs' ability to neutralize obesogenic bisphenols remains limited, but their potential makes this a promising area for future exploration. This review aims to understand the mechanisms of the chemical transformation of bisphenol through its interactions with the gut microbiota and the role of probiotics, particularly NGPs, in these processes. Understanding the interplay between bisphenols, gut microbiota, and NGPs may pave the way for strategies to counteract the negative health effects associated with daily and chronic exposure to bisphenols, which is crucial for food safety and consumer health protection.

Screening (ant)agonistic activities of xenobiotics on the retinoic acid receptor alpha (RARα) using in vitro and in silico analysis

Retinoic acid receptors (RARs) are known as crucial endocrine receptors that could mediate a broad diversity of biological processes. However, the data on endocrine disrupting effects of emerging chemicals by targeting RAR (ant)agonism are far from sufficient. Herein, we investigated the RARα agonistic or antagonistic activities for 75 emerging chemicals of concern, and explored their interactions with this receptor. A recombinant two-hybrid yeast assay was used to examine the RARα activities of the test chemicals, wherein 7 showed effects of RARα agonism and 54 exerted potentials of RARα antagonism. The representative chemicals with RARα agonistic activities, i.e. 4-hydroxylphenol (4-HP) and bisphenol AF (BPAF), significantly increased the mRNA levels of CRABP2 and CYP26A1, while 4 select chemicals with RARα antagonistic potentials, including bisphenol A (BPA), tetrabromobisphenol A (TBBPA), 4-tert-octylphenol (4-t-OP), and 4-n-nonylphenol (4-n-NP), conversely decreased the transcriptional levels of the test genes. The in silico molecular docking analysis using 3 different approaches further confirmed the substantial binding between the chemicals with RARα activities and this nuclear receptor protein. This work highlights the promising strategy for screening endocrine-disrupting effects of emerging chemicals of concern by targeting RARα (ant)agonism.

TDMPP activation of estrogen receptor 2a regulates smc2 and p53 signaling to interfere with liver development in zebrafish (Danio rerio)

Tris (2,6-dimethylphenyl) phosphate (TDMPP), a novel organic phosphorus flame retardant (OPFR), has been found to have estrogenic activity. Estrogens are critical in regulating various biological responses during liver development. However, the effects of TDMPP on zebrafish liver development remain largely unexplored. Here, we utilized a chemical genetic screening approach to assess the estrogenic effects of TDMPP on liver development and to elucidate the underlying molecular mechanism. Our findings revealed that zebrafish larvae exposed to environmentally relevant concentrations of TDMPP (0.05 and 0.5 μM) exhibited concentration-dependent liver impairments, including reduced liver size, histopathological changes, and hepatocyte apoptosis. In addition, E2 caused similar adverse effects to TDMPP, but the pharmacological blockade of estrogen synthesis alleviated the effects on liver development. Chemical inhibitors and morpholino knockdown assays indicated that the reduction of esr2a blocked TDMPP-induced liver impairments, which was further confirmed in the esr2a-/- mutant line. Subsequently, transcriptomic analysis showed that the estrogen receptor activated by TDMPP inhibited the expression of smc2, which was linked to the suppression of liver development through p53 activation. Consistently, overexpression of smc2 and inhibition of p53 evidently rescued hepatic damages induced by TDMPP. Taken together, the above findings identified esr2a, downstream smc2, and p53 as important regulators for the estrogenic effects of TDMPP on liver development. Our work fills crucial gaps in the current knowledge of TDMPP's hepatotoxicity, providing new insights into the adverse effects of TDMPP and the molecular mechanisms of action. These findings underscore the need for further ecological risk assessment and regulatory considerations.

Early-Life Exposure to 4-Hydroxy-4'-Isopropoxydiphenylsulfone Induces Behavioral Deficits Associated with Autism Spectrum Disorders in Mice

Exposure to bisphenol A (BPA) during gestation and lactation is considered to be a potential risk factor for autism spectrum disorder (ASD) in both humans and animals. As a novel alternative to BPA, 4-hydroxy-4'-isopropoxydiphenylsulfone (BPSIP) is frequently detected in breast milk and placental barrier systems, suggesting potential transmission from the mother to offspring and increased risk of exposure. Gestation and lactation are critical periods for central nervous system development, which are vulnerable to certain environmental pollutants. Herein, we investigated the behavioral impacts and neurobiological effects of early-life exposure to BPSIP (0.02, 0.1, and 0.5 mg/kg body weight/day) in mice offspring. Behavioral studies indicated that BPSIP exposure induced ASD-like behaviors, including elevated anxiety-related behavior and decreased spatial memory, in both male and female pups. A distinct pattern of reduced social novelty was observed only in female offspring, accompanied by significant alterations in antioxidant levels. Transcriptome analysis demonstrated that differentially expressed genes (DEGs) were mainly enriched in pathways related to behaviors and neurodevelopment, which were consistent with the observed phenotype. Besides, a decrease in the protein levels of complex IV (COX IV) across all tested populations suggests a profound impact on mitochondrial function, potentially leading to abnormal energy metabolism in individuals with autism. Additionally, changes in synaptic proteins, evidenced by alterations in synapsin 1 (SYN1) and postsynaptic density protein-95 (PSD95) levels in the cerebellum and hippocampus, support the notion of synaptic involvement. These findings suggest that BPSIP may induce sex-specific neurotoxic effects that involve oxidative stress, energy generation, and synaptic plasticity.

Evaluating the Effects of Perinatal Exposures to BPSIP on Hepatic Cholesterol Metabolism in Female and Male Offspring ICR Mice

BACKGROUND

A broad suite of bisphenol S (BPS) derivatives as alternatives for BPS have been identified in various human biological samples, including 4-hydroxyphenyl 4-isopropoxyphenylsulfone (BPSIP) detected in human umbilical cord plasma and breast milk. However, very little is known about the health outcomes of prenatal BPS derivative exposure to offspring.

OBJECTIVES

Our study aimed to investigate the response of hepatic cholesterol metabolism by sex in offspring of dams exposed to BPSIP.

METHODS

Pregnant ICR mice were exposed to 5 μ g / kg body weight (BW)/day of BPSIP, BPS, or E2 through drinking water from gestational day one until the pups were weaned. The concentration of BPSIP, BPS, or E2 in the plasma and liver of pups was determined by liquid chromatography-tandem mass spectrometry. Metabolic phenotypes were recorded, and histopathology was examined for liver impairment. Transcriptome analysis was employed to characterize the distribution and expression patterns of differentially expressed genes across sexes. The metabolic regulation was validated by quantitative real-time PCR, immunohistochemistry, and immunoblotting. The role of estrogen receptors (ERs) in mediating sex-dependent effects was investigated using animal models and liver organoids.

RESULTS

Pups of dams exposed to BPSIP showed a higher serum cholesterol level, and liver cholesterol levels were higher in females and lower in males than in the controls. BPSIP concentration in the male liver was 1.22 ± 0.25  ng / g and 0.69 ± 0.27  ng / g in the female liver. Histopathology analysis showed steatosis and lipid deposition in both male and female offspring. Transcriptome and gene expression analyses identified sex-specific differences in cholesterol biosynthesis, absorption, disposal, and efflux between pups of dams exposed to BPSIP and those in controls. In vivo, chromatin immunoprecipitation analysis revealed that the binding of ER α protein to key genes such as Hmgcr, Pcsk9, and Abcg5 was attenuated in BPSIP-exposed females compared to controls, while it was enhanced in males. In vitro, the liver organoid experiments demonstrated that restoration of differential expression induced by BPSIP in key genes, such as Hmgcr, Ldlr, and Cyp7a1, to levels comparable to the controls was only achieved when treated with a combination of ER α agonist and ER β agonist.

DISCUSSION

Findings from this study suggest that perinatal exposure to BPSIP disrupted cholesterol metabolism in a sex-specific manner in a mouse model, in which ER α played a crucial role both in vivo and in vitro. Therefore, it is crucial to systematically evaluate BPS derivatives to protect maternal health during pregnancy and prevent the transmission of metabolic disorders across generations. https://doi.org/10.1289/EHP14643.

Adverse outcomes of the newly emerging bisphenol A substitutes

BPA and its analogues are facing increasingly stringent regulations restricting their use due to the increasing knowledge of their harmful effects. It is therefore expected that novel BPA analogues and alternatives will replace them in plastic products, cans and thermal paper to circumvent restrictions imposed by legislation. This raises concerns about the safety of "BPA-free" products, as they contain BPA substitutes whose safety has not been sufficiently assessed prior to their market introduction. The regulatory agencies have recognised BPAP, BPBP, BPC2, BPE, BPFL, BPG, BPP, BPPH, BPS-MAE, BPS-MPE, BP-TMC, BPZ and the alternatives BTUM, D-90, UU and PF201 as compound with insufficient data regarding their safety. We demonstrate that the mentioned compounds are present in consumer products, food and the environment, thus exhibiting toxicological risk not only to humans, but also to other species where their toxic effects have already been described. Results of in silico, in vitro and in vivo studies examining the endocrine disruption and other effects of BPA analogues show that they disrupt the endocrine system by targeting various nuclear receptors, impairing reproductive function and causing toxic effects such as hepatotoxicity, altered behaviour and impaired reproductive function. In vitro and in vivo data on BPA alternatives are literally non-existent, although these compounds are already present in commonly used thermal papers. However, in silico studies predicted that they might cause adverse effects as well. The aim of this article is to comprehensively collate the information on selected BPA substitutes to illustrate their potential toxicity and identify safety gaps.

Interaction of Bisphenol A and Its Analogs with Estrogen and Androgen Receptor from Atlantic Cod (Gadus morhua)

The widespread use of bisphenol A (BPA) in polycarbonate plastics and epoxy resins has made it a prevalent environmental pollutant in aquatic ecosystems. BPA poses a significant threat to marine and freshwater wildlife due to its documented endocrine-disrupting effects on various species. Manufacturers are increasingly turning to other bisphenol compounds as supposedly safer alternatives. In this study, we employed in vitro reporter gene assays and ex vivo precision-cut liver slices from Atlantic cod (Gadus morhua) to investigate whether BPA and 11 BPA analogs exhibit estrogenic, antiestrogenic, androgenic, or antiandrogenic effects by influencing estrogen or androgen receptor signaling pathways. Most bisphenols, including BPA, displayed estrogenic properties by activating the Atlantic cod estrogen receptor alpha (gmEra). BPB, BPE, and BPF exhibited efficacy similar to or higher than that of BPA, with BPB and BPAF being more potent agonists. Additionally, some bisphenols, like BPG, induced estrogenic effects in ex vivo liver slices despite not activating gmEra in vitro, suggesting structural modifications by hepatic biotransformation enzymes. While only BPC2 and BPAF activated the Atlantic cod androgen receptor alpha (gmAra), several bisphenols exhibited antiandrogenic effects by inhibiting gmAra activity. This study underscores the endocrine-disrupting impact of bisphenols on aquatic organisms, emphasizing that substitutes for BPA may pose equal or greater risks to both the environment and human health.

Exploring BPA alternatives - Environmental levels and toxicity review

Bisphenol A alternatives are manufactured as potentially less harmful substitutes of bisphenol A (BPA) that offer similar functionality. These alternatives are already in the market, entering the environment and thus raising ecological concerns. However, it can be expected that levels of BPA alternatives will dominate in the future, they are limited information on their environmental safety. The EU PARC project highlights BPA alternatives as priority chemicals and consolidates information on BPA alternatives, with a focus on environmental relevance and on the identification of the research gaps. The review highlighted aspects and future perspectives. In brief, an extension of environmental monitoring is crucial, extending it to cover BPA alternatives to track their levels and facilitate the timely implementation of mitigation measures. The biological activity has been studied for BPA alternatives, but in a non-systematic way and prioritized a limited number of chemicals. For several BPA alternatives, the data has already provided substantial evidence regarding their potential harm to the environment. We stress the importance of conducting more comprehensive assessments that go beyond the traditional reproductive studies and focus on overlooked relevant endpoints. Future research should also consider mixture effects, realistic environmental concentrations, and the long-term consequences on biota and ecosystems.

Associations of prenatal exposure to bisphenols with infant anthropometry: A prospective cohort study

BACKGROUND

Bisphenols (BPs) have been shown to exhibit developmental toxicities. Epidemiological evidence on prenatal BPs exposure and infant growth primarily confined scopes to specific BPs and birth outcomes, with few studies focusing on infant growth and reporting inconsistent findings. The joint effect of prenatal exposure to BPs mixture on infant growth was rarely studied.

OBJECTIVE

This study examined associations of prenatal exposure to individual bisphenol A (BPA) and its analogues (bisphenol F [BPF], bisphenol S [BPS], bisphenol AF [BPAF], and tetrachlorobisphenol A [TCBPA]) and their mixture with infant growth.

METHODS

Urinary concentrations of BPs in pregnant women were quantified. Weight, body mass index, skinfold thickness, and circumference measurements of infants were collected at birth, 6 and 12 months of age, rapid growth and overweight were further defined. Multiple linear regression models and Bayesian kernel machine regression models (BKMR) were used to analyze associations of exposure to individual BPs and BPs mixture with infants' anthropometric measurements, and to identify the important components among mixture. The risks for rapid growth and overweight of each BP were determined using modified Poisson regression models.

RESULTS

A general profile of higher prenatal BPs exposure (mainly BPA, BPF, and BPS) associated with higher anthropometric measurements and higher risks of overweight during infancy was found. We also observed higher risks of rapid growth in infants following prenatal BPs exposure, with risk ratios ranging from 1.46 to 1.91. The joint effect of BPs mixture and single effect of each BP from the BKMR models were consistent with findings from the linear regression models, further suggesting that associations in girls were generally driven by BPA, BPF, or BPS, while in boys mainly by BPF.

CONCLUSION

Prenatal exposure to BPs and their mixture could increase anthropometric measurements of offspring during infancy, with implications of altered growth trajectory in future.

A combined in vitro-in silico method for assessing the androgenic activities of bisphenol A and its analogues

Interactions between endocrine-disruptor chemicals (EDCs) and androgen receptor (AR) have adverse effects on the endocrine system, leading to human reproductive dysfunction. Bisphenol A (BPA) is an EDC that can damage both the environment and human health. Although numerous BPA analogues have been produced as substitutes for BPA, few studies have evaluated their endocrine-disrupting abilities. We assessed the (anti)-androgenic activities of BPA and its analogues using a yeast-based reporter assay. The BPA analogues tested were bisphenol S (BPS), 4-phenylphenol (4PP), 4,4'-(9-fluorenyliden)-diphenol (BPFL), tetramethyl bisphenol F (TMBPF), and tetramethyl bisphenol A (TMBPA). We also conducted molecular docking and dynamics simulations to assess the interactions of BPA and its analogues with the ligand-binding domain of human AR (AR-LBD). Neither BPA nor its analogues had androgenic activity; however, all except BPFL exerted robust anti-androgenic effects. Consistent with the in vitro results, anti-androgenic analogues of BPA formed hydrogen bonding patterns with key residues that differed from the patterns of endogenous hormones, indicating that the analogues display in inappropriate orientations when interacting with the binding pocket of AR-LBD. Our findings indicate that BPA and its analogues disrupt androgen signaling by interacting with the AR-LBD. Overall, BPA and its analogues display endocrine-disrupting activity, which is mediated by AR.

Ultrasonic synthesis of magnetic covalent organic frameworks and application magnetic solid phase extraction for rapid adsorption of trace bisphenols in food samples

A simple ultrasonic synthesis strategy was developed for a novel magnetic covalent organic framework. Firstly, the Fe3O4 nanoparticles were encapsulated by imine-type COF, which generated by the Schiff reaction of 4,4',4''-(1,3,5-Triazine-2,4,6-triyl)-trianiline (TAPT) and tris(4-formylphenyl)-amine (TFPA) using ultrasonic synthesis method within 2 h. The synthesised nanocomposites showed a sizeable specific surface area, and high adsorption capacity. A fast, sensitive MSPE method with Fe3O4@TAPT-TFPA-COF as adsorbent for analysing bisphenol compounds was developed. This method's advantages were simple operation, short extraction time, and avoidance of the use of centrifugal equipment. The method validation indicate that this method exhibited superior linearity, and detection limits range between 0.33 and 0.60 μg L-1. The recoveries of BPs ranged from 74.7 % to 107.0 %, with relative standard deviations of less than 3.8 % in water, milk, vinegar, and soy sauce samples. The proposed method was successfully applied for extracting BPs in food samples.

A 50-gene biomarker identifies estrogen receptor-modulating chemicals in a microarray compendium

High throughput transcriptomics (HTTr) profiling has the potential to rapidly and comprehensively identify molecular targets of environmental chemicals that can be linked to adverse outcomes. We describe here the construction and characterization of a 50-gene expression biomarker designed to identify estrogen receptor (ER) active chemicals in HTTr datasets. Using microarray comparisons, the genes in the biomarker were identified as those that exhibited consistent directional changes when ER was activated (4 ER agonists; 4 ESR1 gene constitutively active mutants) and opposite directional changes when ER was suppressed (4 antagonist treatments; 4 ESR1 knockdown experiments). The biomarker was evaluated as a predictive tool using the Running Fisher algorithm by comparison to annotated gene expression microarray datasets including those evaluating the transcriptional effects of hormones and chemicals in MCF-7 cells. Depending on the reference dataset used, the biomarker had a predictive accuracy for activation of up to 96%. To demonstrate applicability for HTTr data analysis, the biomarker was used to identify ER activators in a set of 15 chemicals that are considered potential bisphenol A (BPA) alternatives examined at up to 10 concentrations in MCF-7 cells and analyzed by full-genome TempO-Seq. Using benchmark dose (BMD) modeling, the biomarker genes stratified the ER potency of BPA alternatives consistent with previous studies. These results demonstrate that the ER biomarker can be used to accurately identify ER activators in transcript profile data derived from MCF-7 cells.

Screening of the Antagonistic Activity of Potential Bisphenol A Alternatives toward the Androgen Receptor Using Machine Learning and Molecular Dynamics Simulation

Over the past few decades, extensive research has indicated that exposure to bisphenol A (BPA) increases the health risks in humans. Toxicological studies have demonstrated that BPA can bind to the androgen receptor (AR), resulting in endocrine-disrupting effects. In recent investigations, many alternatives to BPA have been detected in various environmental media as major pollutants. However, related experimental evaluations of BPA alternatives have not been systematically implemented for the assessment of chemical safety and the effects of structural characteristics on the antagonistic activity of the AR. To promote the green development of BPA alternatives, high-throughput toxicological screening is fundamental for prioritizing chemical tests. Therefore, we proposed a hybrid deep learning architecture that combines molecular descriptors and molecular graphs to predict AR antagonistic activity. Compared to previous models, this hybrid architecture can extract substantial chemical information from various molecular representations to improve the model's generalization ability for BPA alternatives. Our predictions suggest that lignin-derivable bisguaiacols, as alternatives to BPA, are likely to be nonantagonist for AR compared to bisphenol analogues. Additionally, molecular dynamics (MD) simulations identified the dihydrotestosterone-bound pocket, rather than the surface, as the major binding site of bisphenol analogues. The conformational changes of key helix H12 from an agonistic to an antagonistic conformation can be evaluated qualitatively by accelerated MD simulations to explain the underlying mechanism. Overall, our computational study is helpful for toxicological screening of BPA alternatives and the design of environmentally friendly BPA alternatives.

Molecular insights into the effects of tetrachlorobisphenol A on puberty initiation in Wistar rats

Tetrachlorobisphenol A (TCBPA) is the chlorinated derivative of bisphenol A (BPA). Several studies have found that BPA adversely affects the reproductive activity largely through binding to estrogen receptors and the critical period of BPA exposure advances the vaginal opening time in the female offspring via the kisspeptin/G protein-coupled receptor 54 (KGG) system. However, whether TCBPA can affect puberty initiation via KGG and the roles of estrogen receptors in this process remain unknown. Therefore, this study investigated the influence of TCBPA on the onset time of puberty in Wistar rats and the related molecular mechanisms by combing in vitro GT1-7 cells and molecular docking. In female Wistar rats, TCBPA at ≥100 mg/kg bw/day (49.2 μmol/L in rat body) markedly advanced vaginal opening time and increased serum levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), and gonadotropin-releasing hormone (GnRH). It also increased the relative gene expression of LH receptor (LHR), GnRH1, and FSH receptor (FSHR) in hypothalamic-pituitary-gonadal (HPG) axis tissues. In GT1-7 cells, TCBPA increased genes and proteins associated with KGG pathway and activated the extracellular-regulated protein kinase 1/2 (Erk1/2) and phosphatidylinositol-3-kinase/protein kinase B (PI3K/Akt) pathways via G protein-coupled estrogen membrane receptor 1 (GPER1) and estrogen receptor alpha (ERα). Docking analyses supported its interactions with GPER1 and ERα, and treatment with specific inhibitors of ERα- and GPER1-modulated PI3K/Akt and Erk1/2 signaling suppressed its effects. Taken together, TCBPA-induced advancement of puberty initiation in Wistar rats thus results primarily from increased LH, GnRH, and FSH secretion together with GnRH1, FSHR, and LHR upregulation driven by ERα- and GPER1-modulated Erk1/2 and PI3K/Akt signaling. Our results provide new molecular insights into the reproductive toxicity of EDCs.

Bisphenol a alternatives suppress human and rat aromatase activity: QSAR structure-activity relationship and in silico docking analysis

The use of alternative substances to replace bisphenol A (BPA) has been encouraged. The objective of this study was to evaluate the effects of BPA and 9 BPA alternatives on human and rat aromatase (CYP19A1) in human and rat placental microsomes. The results revealed that bisphenol A, AP, B, C, E, F, FL, S, and Z, and 4,4'-thiodiphenol (TDP) inhibited human CYP19A1 and bisphenol A, AP, B, C, FL, Z, and TDP inhibited rat CYP19A1. The IC50 values of human CYP19A1 ranged from 3.3 to 172.63 μM and those of rat CYP19A1 ranged from 2.20 to over 100 μM. BPA alternatives were mixed/competitive inhibitors and inhibited estradiol production in BeWo placental cells. Molecular docking analysis showed that BPA alternatives bind to the domain between heme and steroid and form a hydrogen bond with catalytic residue Met374. Pharmacophore analysis showed that there were one hydrogen bond donor, one hydrophobic region, and one ring aromatic hydrophobic region. Bivariate correlation analysis showed that molecular weight, alkyl atom weight, and LogP of BPA alternatives were inversely correlated with their IC50 values. In conclusion, BPA alternatives can inhibit human and rat CYP19A1 and the lipophilicity and the substituted alkyl size determines their inhibitory strength.

Evaluating the efficiency of the 2020 ban of BPA and BPS in thermal papers in Switzerland

Thermal printing technology requires a color developer to activate the dye under the action of heat. Bisphenol A (BPA) has traditionally been used for this purpose, although it has increasingly been replaced by bisphenol S (BPS) in recent years. Due to concerns regarding their toxicity, the Swiss authorities have banned both BPA and BPS from thermal papers since 2020. The impact of this regulatory decision was evaluated during 3 monitoring campaigns: in 2013-2014, 2019 and 2021. They were used to describe the starting point, the transition phase, and the status after entry into force of the ban, respectively. Whereas the use of BPA as color developer dropped from 82.2% in 2013/14 to 10.8% in 2021, the fraction of BPS-based thermal paper rose from 3.1% to 19.1% during the same period, despite being banned. However, Pergafast® 201 (PF201) is now the main color developer in thermal paper in Switzerland, with an occurrence of 60.3%. Other alternatives such as D-8, TGSA, PPSMU, NKK-1304, BPS-MAE, D-90 and Blue4est® have only been marginally detected. This study demonstrates the efficiency of the regulatory measure and the feasibility to substitute BPA in thermal papers with less-toxic alternatives.

Bisphenol S and F affect cell cycle distribution and steroidogenic activity of human ovarian granulosa cells, but not primary granulosa tumour cells

Bisphenol S (BPS) and F (BPF), a new generation of bisphenols (BPs), are the main substitutes for bisphenol A (BPA). Both have been detected in human body fluids. Importantly, bisphenols are structurally similar to oestrogen, the main sex hormone in females. Because bisphenols bind to nuclear oestrogen receptors (ESR1 and ESR2) and to membrane G-coupled receptor 30 (GPR30), they can disrupt ovarian function. Here, we reveal the molecular mechanism underlying the effects of BPS and BPF on the cell cycle and steroidogenesis in the human ovarian granulosa cell (GC) line HGrC1. We show that BPS and BPF arrest GCs at the G0/G1 phase by inducing expression of cyclin D2, an important event that triggers maximal steroid synthesis in response to the BPS and BPF. We used pharmacological inhibitors to show that BPS and BPF, despite acting via already described pathways, also stimulate steroid secretion via IGF1R pathways in HGrC1 cells. Moreover, we identified differences critical to bisphenols response between normal (HGrC1) and primary tumour granulosa (COV434) cells, that enable COV434 cells to be more resistant to bisphenols. Overall, the data suggest that BPS and BPF drive steroidogenesis in human ovarian GCs by affecting the cell cycle. Furthermore, the results indicate that BPS and BPF act not only via the classical and non-classical ESR pathways, but also via the IGF1R pathway.

Bisphenol S stimulates Leydig cell proliferation but inhibits differentiation in pubertal male rats through multiple mechanisms

Bisphenol S (BPS) is a novel bisphenol A (BPA) analogue, a ubiquitous environmental pollutant that disrupts male reproductive system. Whether BPS affects Leydig cell maturation in male puberty remains unclear. Male Sprague-Dawley rats (age of 35 days) were daily gavaged to 0, 1, 10, 100, and 200 mg/kg/day from postnatal days 35-56. BPS at 1-10 mg/kg/day and higher doses markedly reduced serum testosterone and progesterone levels but it at 200 mg/kg/day significantly increased estradiol level. BPS at 100 and 200 mg/kg/day significantly elevated serum luteinizing hormone (LH) levels. BPS at 1-10 mg/kg/day and higher doses significantly reduced inhibin A and inhibin B levels. BPS at 100 and 200 mg/kg/day markedly increased CYP11A1+ Leydig cell number, but did not affect HSD11B1+ (a mature Leydig cell marker) cell number. BPS at 10 mg/kg/day and higher doses significantly downregulated the expression of Cyp11a1 and at 100 and 200 mg/kg/d significantly lowered Cyp17a1, Hsd11b1, and Nr5a1 in the testes. BPS at 100 and/or 200 mg/kg/day significantly elevated Lhb in the pituitary. BPS at 100 and 200 mg/kg/day significantly increased the phosphorylation of AKT1, AKT2, and CREB without affecting total AKT1, AKT2, and CREB levels. BPS at 1-100 μM significantly suppressed testosterone production and induced proliferation of primary immature Leydig cells after 24 h of treatment and these actions were reversed by estrogen receptor α antagonist, ICI 182780, and partially reversed by vitamin E. BPS at 0.1-10 μM significantly increased oxidative stress of Leydig cells in vitro. BPS also directly inhibited 17β-hydroxysteroid dehydrogenase 3 activity at 10-100 μM. In conclusion, BPS causes hypergonadotropic androgen deficiency in male rats during pubertal exposure via activating ESR1 and inducing ROS in immature Leydig cells and directly inhibiting 17β-hydroxysteroid dehydrogenase 3 activity.

Concentrations of bisphenols and phthalate esters in the muscle of Mediterranean striped dolphins (Stenella coeruleoalba)

Bisphenols (BPs) and phthalate esters (PAEs) are important compounds for the plastics industry, also called "everywhere chemicals" due to their ubiquity in daily use products. Both chemical groups are well-known environmental contaminants, whose presence has been reported in all environmental compartments, and whose effects, mainly associated to endocrine disruption, are detrimental to living organisms. Cetaceans, due to their long life-span, low reproduction rate and high position in the trophic web, are especially vulnerable to the effects of contaminants. However, little is known about BP and PAE concentrations in cetacean tissues, their potential relation to individual biological variables, or their trends over time. Here, the concentration of 10 BPs and 13 PAEs was assessed in the muscle of 30 striped dolphins (Stenella coeruleoalba) stranded along the Spanish Catalan coast (NW Mediterranean) between 1990 and 2018. Six BP and 6 PAE compounds were detected, of which only 4,4'-(cyclohexane-1,1-diyl)diphenol (BPZ) was detected in all the samples, at the highest concentration (mean 16.06 μg g-1 lipid weight). Sex or reproductive condition were largely uninfluential on concentrations: only dimethylphthalate (DMP) concentrations were significantly higher in immature individuals than in adults, and the overall PAE concentrations were significantly higher in males than in females. Temporal variations were only detected in bis(4-hydroxyphenyl)ethane (BPE), diethylphthalate (DEP) and dimethylphthalate (DMP), whose concentrations were lower, and 9,9-Bis(4-hydroxyphenyl)fluorene (BPFL), which were higher, respectively, in samples taken between 2014 and 2018, probably reflecting shifts in the production and use of these chemicals. These results provide the first assessment of concentrations of several BP and PAE compounds in the muscle of an odontocete cetacean.

The roles of membrane permeability and efflux pumps in the toxicity of bisphenol S analogues (2,4-bisphenol S and bis-(3-allyl-4-hydroxyphenyl) sulfone) to Escherichia coli K12

Bisphenol S (BPS) analogues are a group of recently reported emerging contaminants in the environment. Bacteria are important components of food webs. However, the potential risks of BPS analogues in bacteria have not been fully addressed. The toxicity effects and related mechanisms of two BPS analogues with different molecular weights (2,4-bisphenol S (2,4-BPS) and bis-(3-allyl-4-hydroxyphenyl) sulfone (TGSA)) on Escherichia coli K12 were compared. The minimum inhibitory concentration (MIC) of 2,4-BPS in the wild-type of E. coli K12 was lower than that of TGSA. The membrane permeability of the wild-type increased significantly after exposed to the same concentrations (0.5-50 nmol L^-1) of 2,4-BPS and TGSA. In addition, 2,4-BPS induced more significant changes in membrane permeability than TGSA. Hormetic effects of 2,4-BPS and TGSA in the wild-type strain were noted in the levels of outer membrane proteins (ompC and ompF), multidrug efflux pump acriflavine resistance B (acrB) and type II topoisomerases. Transcriptomic results indicated these two BPS analogues inhibited the function of ABC transporters. In contrast to TGSA, 2,4-BPS affected DNA replication, tricarboxylic acid cycle, oxidative phosphorylation, and inhibited energy metabolism. Compared with wild-type strain, the ΔacrB mutant strain showed enhanced susceptibility to 2,4-BPS and TGSA with their MICs reduced by 20% and 11%, respectively. Deletion of the acrB affected the growth characteristics and induced stronger oxidative stress than the wild-type strain when exposed to 2,4-BPS or TGSA. The results suggested that 2,4-BPS were more toxic to E. coli K12 than TGSA in the concentration range of 0.5-50 nmol L^-1, which was supported by the evidence from their impacts on membrane permeability and efflux pumps.

Evaluation of the bisphenol A-induced vascular toxicity on human umbilical artery

Bisphenol A (BPA) is one of the most widely used synthetic compound in the manufacture of polycarbonate plastics and epoxy resins. Worryingly, BPA is an endocrine disrupting chemical (EDC) with an estrogenic, androgenic, or anti-androgenic activities. However, the vascular implications of BPA exposome in pregnancy is unclear. In this sense, the present work proposed to understand how BPA exposure impair the vasculature of the pregnant women. To elucidate this, ex vivo studies were performed using human umbilical arteries to explore the acute and chronic effects of BPA. The mode of action of BPA was also explored by analysing the activity (by ex vivo studies) and expression (in vitro studies) analysis of Ca²⁺ and K⁺-channels and soluble guanyl cyclase. Moreover, in silico docking simulations were performed to unveil the modes of interactions of BPA with the proteins involved in these signalling pathways. Our study showed that the exposure to BPA may modify the vasorelaxant response of HUA, interfering with NO/sGC/cGMP/PKG pathway by modulation of sGC and activation of BKCa channels. Moreover, our findings suggest that BPA can modulate the HUA reactivity, increasing the L-type Ca²⁺ Channels (LTCC) activity, a common vascular response observed in hypertensive disorders of pregnancy.

Bisphenol P exposure in C57BL/6 mice caused gut microbiota dysbiosis and induced intestinal barrier disruption via LPS/TLR4/NF-κB signaling pathway

Despite being one of the most world's widely used and mass-produced compounds, bisphenol A (BPA) has a wide range of toxic effects. Bisphenol P (BPP), an alternative to BPA, has been detected in many foods. The effects of BPP dietary exposure on gut microbiota and the intestinal barrier were unclear. We designed three batches of animal experiments: The first studied mice were exposed to BPP (30 µg/kg BW/day) for nine weeks and found that they gained weight and developed dysbiosis of the gut microbiota. The second, using typical human exposure levels (L, 0.3 µg/kg BW/day BPP) and higher concentrations (M, 30 µg/kg BW/day BPP; H, 3000 µg/kg BW/day BPP), caused gut microbiota dysbiosis in mice, activated the Lipopolysaccharide (LPS) /TLR4/NF-κB signaling pathway, triggered an inflammatory response, increased intestinal permeability, and promoted bacterial translocation leading to intestinal barrier disruption. The third treatment used a combination of antibiotics and alleviated intestinal inflammation and injury. This study demonstrated the mechanism of injury and concentration effects of intestinal damage caused by BPP exposure, providing reference data for BPP use and control and yielding new insights for human disease prevention.

Binding, activity and risk assessment of bisphenols toward farnesoid X receptor pathway: In vitro and in silico study

Bisphenols have been identified as emerging environmental pollutants of high concern with potential adverse effects through interactions with receptor-mediated pathways. However, their potential mechanism of action and health risks through the farnesoid X receptor (FXR) pathway remain poorly understood. In the present study, we aimed to explore the potential disruption mechanism of bisphenols through the FXR signalling pathway. Receptor binding assays showed that bisphenols bound to FXR directly, with tetrabromobisphenol A (TBBPA; 34-fold), tetrachlorobisphenol A (TCBPA; 8.7-fold), bisphenol AF (BPAF; 2.0-fold), and bisphenol B (BPB; 1.9-fold) showing a significantly stronger binding potency than bisphenol A (BPA). In receptor transcriptional activity assays, bisphenols showed agonistic activity toward FXR, with BPAF, BPB, and bisphenol F (BPF) exhibiting higher activity than BPA, but TBBPA and TCBPA showing significantly weaker activity than BPA. Molecular docking results indicated that the number of hydrogen bonds dictated their binding strength. Intracellular concentrations of bisphenols were quantified using liquid chromatography-tandem mass spectrometry (LC-MS/MS) in receptor activity assays, and it was found that the intracellular concentrations of TBBPA and TCBPA were 40-fold lower than those of BPA. Using the bioactivity concentrations in the FXR receptor activity assay, the liver concentrations of bisphenols were estimated using physiologically-based pharmacokinetic (PBPK) models through their serum concentrations, and the hazard quotient (HQ) values were calculated. The results suggest a potentially high concern for the risk of activating the FXR pathway for some populations with high exposure. Overall, these results indicate that bisphenols can bind to and activate FXR receptors, and that the activation mechanism is dependent on cellular uptake and binding strength. This study provides important information regarding the exposure risk of bisphenols, which can promote the development of environmentally friendly bisphenols.

Exploration of the damage and mechanisms of BPS exposure on the uterus and ovary of adult female mice

Bisphenol S (BPS) has been followed with interest for its endocrine disrupting effects, but exploration on the reproductive system of adult females is lack of deep investigation. In the present study, adult female CD-1 mice were treated with BPS for 28 days at 300 μg/kg/day. After that, uteruses and ovaries were harvested for histopathological examination, RNA-seq analysis, and diseases risk prediction. Hematoxylin-eosin (H&E) staining results showed significant histological alterations in the uterus and ovary of the BPS-exposed mice. Bioinformatics analysis of the RNA-seq screened a certain number of differentially expressed genes (DEGs) in both uterus and ovary between BPS group and their corresponding vehicle control groups (Veh), respectively. Functional enrichment analysis of DEGs found that hormone metabolism and immunoinflammatory related pathways were enriched. Disease risk evaluation of the hub genes was performed and the results indicated that diseases associated with uterus and ovary were mainly related to tumors and cancers. Further pan cancer and ovarian cancer survival analysis based on human diseases database pointed out, Foxa1, Gata3, S100a8 and Shh for uterus, Itgam, Dhcr7, Fdps, Hmgcr, Hsd11b1, Hsd3b1, Ptges, F3, Fn1, Ptger4 and Srd5a1 for ovary were significant correlation with cancer. The findings suggest that BPS causes some histopathological changes, alters the expressions of hub genes, enhances uterine and ovarian tumors or even cancer risks.

Occurrence of multiple bisphenol S analogues in children from Shantou, China

Emerging bisphenol S analogues (BPSs) have gained their application perspectives to replace bisphenol A (BPA) and BPA analogues (BPAs). However, the extent of human exposure and potential health risk from BPSs is rarely known yet. We hypothesized that children living in Shantou, China, a well-known e-waste recycling city, may expose to emerging BPSs together with BPA and BPAs. In this study, BPA, six commonly used BPAs and 11 emerging BPSs were determined simultaneously in 240 urine samples collected from children residing in Shantou. BPA, BPS, bisphenol F, bisphenol AF and three BPSs of 2,4'-bis(hydroxyphenyl)sulfone, 4-((4-(allyloxy)phenyl)sulfonyl)phenol and diphenylsulfone (DPS) were the urinary predominant bisphenols with detection frequencies of 67-100% in the children. BPA was found at the highest median concentration (3.36 µg/g creatinine) followed by BPS (0.313) and DPS (0.187). It is interesting to find that the girls and children in the younger group (2 ≤ age < 5) had consistently higher concentrations of the seven dominant bisphenols than the boys and these of the older group (5 ≤ age ≤ 10), respectively. The children with under/overweight suffered higher burdens of bisphenol exposure based on medians of estimated daily intakes. Association analysis results indicated that the Shantou children exposed themselves to multiple BPSs along with BPA and BPAs from assumed consumer products and/or contaminated environments.

Direct inhibition of bisphenols on human and rat 11β-hydroxysteroid dehydrogenase 2: Structure-activity relationship and docking analysis

Bisphenols (BPs) as endocrine-disrupting compounds have drawn attention to their health hazards. Whether a BP interferes with glucocorticoid metabolism remains unclear. 11β-Hydroxysteroid dehydrogenase 2 (11β-HSD2) is a key glucocorticoid-metabolizing enzyme that controls fetal glucocorticoid levels across the placental barrier and mineralocorticoid receptor specificity in the kidney. In this study, 11 BPs were tested to inhibit human placental and rat renal 11β-HSD2 and were analyzed for inhibitory potency, mode action, and docking parameters. BPs had inhibitory potency against human 11β-HSD2: BPFL>BPAP>BPZ>BPB>BPC>BPAF>BPA>TDP and the IC₁₀ values were 0.21, 0.55, 1.04, 2.04, 2.43, 2.57, 14.43, and 22.18 μM, respectively. All BPs are mixed inhibitors except BPAP, which is a competitive inhibitor for human 11β-HSD2. Some BPs also inhibited rat renal 11β-HSD2, with BPB (IC₅₀, 27.74 ± 0.95) > BPZ (42.14 ± 0.59) > BPAF (54.87 ± 1.73) > BPA (77.32 ± 1.20) > other BPs (about 100 μM). Docking analysis showed that all BPs bound to the steroid-binding site, interacting with the catalytic residue Tyr232 of both enzymes and the most potent human 11β-HSD2 inhibitor BPFL acts possibly due to its large fluorene ring that has hydrophobic interaction with residues Glu172 and Val270 and π-stacking interaction with catalytic residue Tyr232. The increase in the size of substituted alkanes and halogenated groups in the methane moiety of the bridge of BPs increases its inhibitory potency. Regressions of the lowest binding energy with inhibition constant indicated that there was an inverse regression. These results indicated that BPs significantly inhibited human and rat 11β-HSD2 activity and that there were species-dependent differences.

Broadening the lens on bisphenols in coastal waters: Occurrence, partitioning, and input fluxes of multiple novel bisphenol S derivatives along with BPA and BPA analogues in the Pearl River Delta, China

Bisphenol S derivatives (BDs) are being widely used as novel substitutes for BPA and BPA analogues (BPAs), causing pollution in various environmental compartments. However, the occurrence and fate of BDs in coastal waters are currently unknown. To broaden the lens on bisphenols in coastal waters, this study measured a broad suite of 23 bisphenols, including 12 BDs along with BPA and 10 BPAs, in water, suspended particulate matter (SPM), and sediment from eight major outlets of the Pearl River Delta, China (PRD). In addition to BPA and BPAs, all the 12 BDs were detected in the collected samples. The total concentration of 12 BDs ranged from 1.2 to 25 ng/L (median of 4.3 ng/L) in water samples, 0.80-13 ng/g dw (median of 3.0 ng/g dw) in SPM samples and 0.48-3.7 ng/g dw (median of 0.64 ng/g dw) in sediment samples. For most individual BDs, they had comparable concentrations to individual BPAs. In addition, logK_d values of the frequently detected bisphenols, including BPA, BPS, BPF, 4-((4-Isopropoxyphenyl)sulfonyl)phenol (BPSIP), 2,4-bis(phenylsulfonyl)phenol (DBSP), and other 9 bisphenols, were significantly correlated with their logK_ow values (R² = 0.38, p < 0.05), indicating that the partitioning of bisphenols between the aqueous and SPM phases were strongly influenced by hydrophobic interaction. Based on bisphenols' concentrations in water from the eight outlets of PRD, the estimated input fluxes of novel BDs (1900 kg/y) were found to be even higher than that of BPAs (550 kg/y). This indicates that the riverine input of BDs into the coastal environment is gradually increasing, which should be taken seriously in the future.

The role of small GTPases in bisphenol AF-induced multinucleation in comparison with dibutyl phthalate in the male germ cells

The goal of this study is to examine bisphenol AF (BPAF)-induced multinucleation (MNC) in comparison with dibutyl phthalate (DBP), known to induce MNC in mouse gonocytes in vivo. We performed image-based single-cell high content analysis (HCA) in the mouse spermatogonia C18-4 cells treated with various concentrations of BPAF and DBP. BPAF as low as 5 µM was cytotoxic and resulted in 40% cell death of the C18-4 cells after 72 h. HCA revealed that 5 µM of BPAF significantly increased the number of MNC by an average of 3.6-fold. DBP did not induce MNC in the doses we tested. Cytokinesis is tightly regulated by various small GTPase-signaling pathways. We, therefore, tested 5 selective GTPase inhibitors and found that Y27632, a ROCK inhibitor, reduced the BPAF-induced MNC by nearly 30%. Inhibition of Cdc42 by ML141 conversely increased the number of BPAF-induced MNC. We performed a hierarchical cluster analysis of the HCA data and demonstrated that the cytoskeletal disruption by BPAF was reversely modified by Y27632. We found that mRNA expression of genes regulating Rho and Rac GTPase activities, p190RhoGap and MgcRacGap, was altered in BPAF-treated C18-4 cells in a time-dependent manner. Multinucleated gonocytes are often indicators of disease pathologies. Our results provided the first evidence of mechanisms of the dual toxicity by BPAF to male germ cells, which induces chromosome endoreplication without the coordinated cytokinetic cellular components. The unique genotoxic mechanism of forming multinucleated germ cells suggests a novel mode of action in the male repro-toxicity concern over the increasingly ubiquitous presence of BPA analogs.

Exposure to tris(2,6-dimethylphenyl) phosphate interferes with sexual differentiation via estrogen receptors 2a and 2b in zebrafish

Tris(2,6-dimethylphenyl) phosphate (TDMPP), an emerging organophosphate flame retardant, is frequently detected in multiple environmental media. Although TDMPP has been proven as a compound with estrogenic activity, its feminizing effects on reproductive system remain unclear. This study investigated the adverse effects of TDMPP on gonadal development by exposing zebrafish for 105 days from 15 days post-fertilization. Exposure to TDMPP (0.5 and 5 μM, corresponding to about 200 and 2000 μg/L) induced ovarian formation in aromatase mutant (cyp19a1a-/-) line which normally presents all-male phenotype for deficiency of endogenous estrogen (E2), suggesting its feminizing effect on sexual differentiation. In addition, TDMPP also interfered with other aspects of reproduction by delaying puberty onset, retarding sexual maturation, impairing gametogenesis and subfertility. Molecular docking and reporter gene assay indicated that all three nuclear estrogen receptors (nERs) can be binded to and activated by TDMPP. Using a series of nERs mutant lines, we confirmed the indispensable role of esr2a and esr2b in mediating the feminizing effects of TDMPP. Further analysis revealed that the prominent effects of TDMPP on sexual differentiation correlated to upregulation of female-promoting genes and downregulation of male-promoting genes. Taken together, the present study provided unequivocal genetic evidence for estrogenic effects of TDMPP on reproductive system and its molecular mechanisms of action.