Bisphenol analogues induced metabolic effects through eliciting intestinal cell heterogeneous response

Low-dose tire wear chemical 6PPD-Q exposure elicit fatty liver via promoting fatty acid biosynthesis in ICR mice

N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine-quinone (6PPD-Q) as a major metabolite of tire wear chemical 6PPD has been demonstrated to be an emerging burden of exposure in human populations, via contamination from drinking water, air particulate matter and food sources. Whilst increasing attention has been moved toward its adverse effect, the potential hepatotoxicity of 6PPD-Q in mammals at realistic dose remains unknown. Here, the toxic effects of 6PPD-Q at environmentally relevant dose on the liver of adult mice and its underlying mechanism were investigated through an integrative approach combining transcriptomic and lipidomic analyses. We found that 6PPD-Q exposure induced excessive lipid deposition following three weeks of exposure, ultimately contributing to the pathogenesis of fatty liver disease. Mechanistically, 6PPD-Q exposure caused a remarkable increase in the contents of fatty acids within the hepatic tissue of mice by enhancing their biosynthesis, thereby facilitating lipid deposition. In summary, this study provides a new understanding on the endocrine disrupting effects of 6PPD-Q on hepatic lipid metabolism and how it may contribute to elevated risk of fatty liver disease. Our findings call for a potential public health attention on the risk assessment of 6PPD-Q, particularly towards the risk of chronic metabolic diseases.

Selenium-enriched Lactiplantibacillus plantarum alleviates alkalinity stress-induced selective hepatic insulin resistance in common carp

Carbonate alkalinity is one of the primary factors limiting saline-alkaline water aquaculture, and high alkalinity can lead to respiratory alkalosis, which is hazardous to fish health. Selenium (Se) and Lactiplantibacillus plantarum (L. plantarum) can be used for the biosynthesis of organic selenium (selenium-enriched Lactiplantibacillus plantarum: SL), which has low toxicity, high bioavailability, and the promotion of metabolism. Additionally, it can be used as a feed additive in aquaculture. In the present study, we established a model of chronic alkalinity stress in common carp and added SL to the feed. We found that alkalinity stress can cause severe hepatic dysfunction in common carp, as well as disrupt the intestinal barrier, further contributing to the translocation of enterogenous lipopolysaccharides through portal circulation and exacerbating liver injury. SL alleviated glucose-lipid metabolism abnormalities of the liver while reducing serum LPS levels and reduction of enterogenous LPS translocation to the liver, thus significantly reducing the degree of intestinal villi damage, hepatocyte vacuolisation, and nuclear damage. The significantly increased activities of SOD, GSH-Px, CAT, and T-AOC revealed that SL improved the antioxidant capacity of common carp. SL inhibited the alkalinity stress-induced overexpression of genes related to lipid synthesis and gluconeogenesis by modulating the P13K/Akt/FoxO1 signalling pathway, thus alleviating selective hepatic insulin resistance. SL attenuated the inflammatory response by modulating the mRNA expression levels of IL-7, IL-6, TNF-α and IL-10. In addition, apparent increase in the abundance of pathogenic bacteria (Brevinema, Bosea, Luteolibacter, and Vibrio) and apparent reduction in the abundance of beneficial bacteria (Cetobacterium, ZOR0006, and Shewanella) were closely related to the hepato-intestinal circulation process in carp exposed to alkalinity stress. SL regulated the hepato-intestinal circulation, reduced the abundance of Brevinema, Bosea, Luteolibacter, and Vibrio, increased the abundance of Cetobacterium, ZOR0006, and Shewanella, alleviated alkalinity stress-induced damage to intestinal microvilli (villus height and width), and significantly restored normal liver and intestinal functions. This study reveals the physiological regulatory mechanism by which Se-enriched L. plantarum through liver-intestinal axis alleviates alkalinity stress-induced hepatic insulin resistance and may provide new ideas and a theoretical basis for protecting against alkalosis and treating insulin resistance.

How fish intestinal cells responded to dietary methylmercury exposure? A single-cell transcriptomic analysis

Fish intestine is not only an important digestive and immune organ, but also serves as the first barrier to defend against methylmercury (MeHg) toxicity. Numerous studies have examined the responses of intestine to MeHg, whereas the heterogeneous responses of intestinal cells have not been addressed. In this study, the gilthead seabream were exposed to dietary MeHg, and the gene expression profiles of different intestinal cell populations were examined using scRNA-seq technique. We demonstrated that among the 14 cell types identified, enterocytes, macrophages, T cells and goblet cells were the primary target cell populations exhibiting specific responses to MeHg. Enterocytes appeared to play the most important role in the MeHg transport across the intestinal epithelium as well as intracellular storage. The immune pathways of macrophages and T cells were suppressed by MeHg, which also interfered with the mucus production and secretion in the goblet cells. Furthermore, MeHg not only affected the cell-cell adhesion of the target cells, but also resulted in disorder of lipid metabolism and immune function, thereby leading to increased susceptibility to pathogenic infections. This study provides an important understanding of the specific responses of intestinal cells to MeHg exposure at the cellular level.

The impact of bisphenol AF on skeletal muscle function and differentiation in vitro

Various environmental chemicals have been identified as contributors to metabolic diseases. Bisphenol AF (BPAF), a substitute for bisphenol A, has been associated with changes in glucose metabolism and incidence of type 2 diabetes mellitus in humans. However, its mode of action remains unclear. Considering that skeletal muscle is the primary tissue for glucose utilization and the development of insulin resistance, yet largely neglected in toxicological assessments, we investigated the impact of BPAF on skeletal muscle function and differentiation. We examined the effects of BPAF (0.01-10 μM) on glucose uptake, response to insulin, production of reactive oxygen species (ROS), intracellular calcium, and myocyte differentiation, during hyperglycemia, insulin stimulation, and muscle contraction. We used the rat myoblast cell line L6 differentiated into myotubes, and murine primary isolated muscle fibers. In myotubes and contracting adult fibers, BPAF increased mitochondrial ROS. Basal glucose uptake was increased in myotubes while cells' ability to respond to insulin was decreased. Additionally, in developing myotubes, differentiation markers were downregulated with BPAF, along with impaired formation of tube structures. These effects were primarily observed at 10 μM concentration, which is markedly higher than reported human exposure concentrations. The results provide an insight into potential hazards associated with BPAF in terms of metabolic disruption in skeletal muscle. The developed in vitro methods show promise for future usage in assessments of new chemicals and their mixtures.

Environmental contamination by bisphenols: From plastic production to modulation of the intestinal morphophysiology in experimental models

Bisphenols are frequently found in a range of plastic products and have been associated with the development of diseases such as diabetes mellitus type 2 and obesity. These compounds are known as endocrine disruptors and have led to restrictions on their use due to their presence in the environment and their association with non-communicable chronic diseases. The gastrointestinal tract, being the primary site of food and water absorption, is particularly vulnerable to the effects of bisphenols. For this reason, a review of studies showing associations between bisphenols exposure and adverse effects in the gut microbiota, morphology tissue, gut permeability, and on the enteric nervous system was carried out. We have included perinatal studies and in different adult experimental models. The effects of bisphenol exposure on the gut microbiota are complex and varied. Bisphenol exposure generally leads to a decrease in microbial diversity and may impact the integrity of the intestinal barrier, resulting in elevated levels of inflammation, changes in morphological and metabolic characteristics of the gut, modifications in tight junction expression, and changes in goblet cell expression. In addition, bisphenol exposure in the perinatal phase can lead to important intestinal changes, including increased colonic inflammation and decreased colonic paracellular permeability.

Microplastics in aquatic ecosystems: Detection, source tracing, and sustainable management strategies

Microplastics (MPs) are emerging contaminants characterized by persistence, cross-media transport, and complex pollutant interactions, posing serious ecotoxicological risks to ecosystems and human health. Effective MPs management requires multi-faced, long-term, strategies involving targeted sampling, quantitative detection, and comprehensive risk assessments, all of which entail significant resource investment. Despite advancements in remediation technologies, a holistic governance framework integrating these innovations remains underdeveloped. This review synthesizes current knowledge on MPs, elaborating on their diverse morphologies, degradation pathways, and their role as vectors for toxic substances. State-of-the-art extraction techniques are evaluated in this article, including micropore adsorption using nanocomposites, alongside the incorporation of advanced analytical tools such as spectroscopic methods, electron microscopy, and bioinformatics to augment environmental forensics. This review also underscores the necessity of formulating robust global policies to regulate MPs pollution and discusses the potential of biodegradation and thermal degradation as sustainable solutions for MPs removal. By promoting an interdisciplinary approach, this review advocates for a coordinated global response, integrating environmental science, policy frameworks, and waste management strategies to mitigate the escalating impact of MPs on ecosystems and human well-being.

Environmental concentrations of 6PPD and 6PPD-quinone induce hepatic lipid metabolism disorders in male black-spotted frogs

Aquatic environments are generally contaminated with N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD) and its oxidation product 6PPD-quinone (6PPD-Q). Recently, 6PPD-Q was found lethally toxic to some specific species, especially salmonid silverfish. This study investigated male black-spotted frogs (Pelophylax nigromaculatus) exposed to 6PPD and 6PPD-Q with different environmental concentrations (0, 1, and 10 μg/L) for 21 days, after which biochemical, metabolomic, gene expression analyses, and molecular docking were conducted. 6PPD and 6PPD-Q were both found to bioaccumulate in frogs' livers in a dose-dependent manner and produce a significant reduction of the hepatosomatic index. Metabolomics data showed that 6PPD and 6PPD-Q induced distinct alterations in metabolite expression, predominantly within pathways associated with the biosynthesis of unsaturated fatty acids as well as the metabolism of arachidonic and linoleic acids. Exposure to 10 μg/L 6PPD and 6PPD-Q increased the cholesterol level by 2.22 and 4.35 folds, and the triglyceride level by 1.90 and 2.25 folds, respectively. 6PPD-Q inhibited the enzyme activity and gene expression involved in lipolysis, and promoted the lipid synthesis. Moreover, 6PPD and 6PPD-Q bound to peroxisome proliferators-activated receptors of α and γ. In conclusion, 6PPD and 6PPD-Q with environmental concentrations induced frogs' lipid metabolism disorders. These findings contribute to our understanding of 6PPD and 6PPD-Q health risks in amphibians.

Metabolic disrupting chemicals in the intestine: the need for biologically relevant models: Zebrafish: what can we learn from this small environment-sensitive fish?

Although the concept of endocrine disruptors first appeared almost 30 years ago, the relatively recent involvement of these substances in the etiology of metabolic pathologies (obesity, diabetes, hepatic steatosis, etc.) has given rise to the concept of Metabolic Disrupting Chemicals (MDCs). Organs such as the liver and adipose tissue have been well studied in the context of metabolic disruption by these substances. The intestine, however, has been relatively unexplored despite its close link with these organs. In vivo models are useful for the study of the effects of MDCs in the intestine and, in addition, allow investigations into interactions with the rest of the organism. In the latter respect, the zebrafish is an animal model which is used increasingly for the characterization of endocrine disruptors and its use as a model for assessing effects on the intestine will, no doubt, expand. This review aims to highlight the importance of the intestine in metabolism and present the zebrafish as a relevant alternative model for investigating the effect of pollutants in the intestine by focusing, in particular, on cytochrome P450 3A (CYP3A), one of the major molecular players in endogenous and MDCs metabolism in the gut.

Heterogeneity effects of bisphenol A and its substitute, fluorene-9-bisphenol, on intestinal homeostasis

Bisphenol A (BPA) and its substitute fluorene-9-bisphenol (BHPF) are used in consumer products; however, their toxic effects on intestinal epithelium remain largely unknown. In this study, we combined intestinal organoids and single-cell RNA sequencing to investigate the impact of BPA and BHPF exposure on intestinal cell composition, differentiation, and function. Both compounds inhibited the growth of small intestinal organoids, with BHPF exhibiting a more potent inhibitory effect. BPA and BHPF did not significantly alter the overall cell type composition; however, they led to different alterations in cell-cell communications. Gene Ontology enrichment analysis showed that BPA and BHPF exposures affected various biological processes, such as glutathione transferase activity, antioxidant activity, and lipid metabolism, in cell type-specific and compound-dependent manners. Trajectory analysis demonstrated that BPA and BHPF altered the differentiation trajectory of the intestinal cells. To further connect the cellular mechanism to the phenotypic impact in vivo, we constructed a mouse model exposed to BPA or BHPF and observed significant alterations in intestinal morphology, including reduced crypt depth and villus length and impaired stem cell proliferation and self-renewal. These results provide novel insights into the cell type-specific effects of BPA and BHPF on the intestinal epithelium and highlight the potential risks of exposure to these compounds. Our findings underscore the importance of evaluating the safety of BPA substitutes and contribute to a better understanding of the effects of environmental chemicals on gut health.

Combining Multiple Omics with Molecular Dynamics Reveals SCP2-Mediated Cytotoxicity Effects of Aflatoxin B1 in SW480 Cells

Aflatoxins belong to a class of mycotoxins, among which aflatoxin B1 (AFB1) has detrimental effects on the health of both animals and humans. It is associated with long-term exposure-induced carcinogenicity, hepatotoxicity, renal toxicity, neurotoxicity, and immunosuppressive properties, resulting in a variety of diseases. The intestine is the first barrier for human exposure to AFB1, but limited investigations have been conducted to clarify the underlying mechanisms of intestinal cytotoxicity. The mechanism of AFB1-induced cytotoxicity was investigated in this study using an integrated approach combining transcriptome, proteome, and metabolome analysis along with molecular dynamics simulation. After exposing SW480 cells to 50 μM AFB1 for 72 h, the transcriptome, proteome, and metabolome exhibited significant enrichment in pathways associated with oxidative stress, fatty acid and lipid metabolism, and glutathione metabolism. The experimental results demonstrated that AFB1 significantly reduces SW480 cells viability, and induces oxidative stress, calcium overload, mitochondrial damage, and lipid metabolism disorders.

Comparative toxicological assessment of 2 bisphenols using a systems approach: evaluation of the behavioral and transcriptomic responses of Danio rerio to bisphenol A and tetrabromobisphenol A

The zebrafish (Danio rerio) is becoming a critical component of new approach methods (NAMs) in chemical risk assessment. As a whole organism in vitro NAM, the zebrafish model offers significant advantages over individual cell-line testing, including toxicokinetic and toxicodynamic competencies. A transcriptomic approach not only allows for insight into mechanism of action for both apical endpoints and unobservable adverse outcomes, but also changes in gene expression induced by lower, environmentally relevant concentrations. In this study, we used a larval zebrafish model to assess the behavioral and transcriptomic alterations caused by subphenotypic concentrations of 2 chemicals with the same structural backbone, the endocrine-disrupting chemicals bisphenol A and tetrabromobisphenol A. Following assessment of behavioral toxicity, we used a transcriptomic approach to identify molecular pathways associated with previously described phenotypes. We also determined the transcriptomic point of departure for each chemical by modeling gene expression changes as continuous systems which allows for the identification of a single concentration at which toxic effects can be predicted. This can then be investigated with confirmatory cell-based testing in an integrated approach to testing and assessment to determine risk to human health and the environment with greater confidence. This paper demonstrates the impact of using a multi-faceted approach for evaluating the physiological and neurotoxic effects of exposure to structurally related chemicals. By comparing phenotypic effects with transcriptomic outcomes, we were able to differentiate, characterize, and rank the toxicities of related bisphenols, which demonstrates methodological advantages unique to the larval zebrafish NAM.

High-Throughput GPCRome Screen of Pollutants Reveals the Activity of Polychlorinated Biphenyls at Melatonin and Sphingosine-1-phosphate Receptors

Exposure to environmental pollutants is linked to numerous toxic outcomes, warranting concern about the effect of pollutants on human health. To assess the threat of pollutant exposure, it is essential to understand their biological activity. Unfortunately, gaps remain for many pollutants' specific biological activity and molecular targets. A superfamily of signaling proteins, G-protein-coupled receptors (GPCRs), has been shown as potential targets for pollutant activity. However, research investigating the pollutant activity at the GPCRome is scarce. This work explores pollutant activity across a library of human GPCRs by leveraging modern high-throughput screening techniques devised for drug discovery and pharmacology. We designed and implemented a pilot screen of eight pollutants at 314 human GPCRs and discovered specific polychlorinated biphenyl (PCB) activity at sphingosine-1-phosphate and melatonin receptors. The method utilizes open-source resources available to academic and governmental institutions to enable future campaigns that screen large numbers of pollutants. Thus, we present a novel high-throughput approach to assess the biological activity and specific targets of pollutants.

Bisphenol analogues induced social defects and neural impairment in zebrafish

There is evidence in humans that endocrine disrupting chemicals exposure, such as bisphenol A (BPA), is tied to social behavior impacts when evaluated in early life stage. However, the potential social impact of BPA alternatives and its association with central nervous system (CNS) is poorly understood. Here, we performed behavioral test for zebrafish that are continuously exposed to environmental relevant concentrations (5 and 500 ng/L) of BPA, BPF, and BPAF since embryonic stage. Surprisingly, significant social behavior defects, including increased social distance and decreased contact time, were identified in zebrafish treated by 500 ng/L BPAF and BPA. These behavioral changes were accompanied by apparent histological injury, microglia activation, enhanced apoptosis and neuron loss in brain. The gut-brain transcriptional profile showed that genes involved in neuronal development pathways were up-regulated in all bisphenol analogs treatments, indicating a protective phenotype of CNS; however, these pathways were inhibited in gut. Besides, a variety of key regulators in the gut-brain regulation were identified based on protein interaction prediction, such as rac1-limk1, insrb1 and fosab. These findings implicated that the existence of bisphenol analogues in water would influence the social life of fish, and revealed a potential role of gut-brain transcriptional alteration in mediating this effect.

Target Exposome for Characterizing Early Gestational Exposure to Contaminants of Emerging Concern and Association with Gestational Diabetes Mellitus

Characterization of gestational exposure to complex contaminants of emerging concern (CECs) is critical to the identification of environmental risk factors for pregnancy complications. However, determination of various CECs with diverse physicochemical properties in biological fluids is technically challenging. In the present study, we developed a target exposome protocol, consisting of simple liquid-liquid extraction-based sample preparation and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis, to determine 325 CECs covering 11 subclasses, including poly- and perfluoroalkyl substances, organophosphate esters, ultraviolet (UV) stabilizers, synthetic antioxidants, phthalate esters, and several others. The protocol exhibits exceptional advantages over traditional approaches in the coverage of chemicals, sample volume demand, and time and financial cost. The protocol was applied in a prospective nested gestational diabetes mellitus (GDM) study including 120 cases and 240 matched healthy controls. Thirty-three CECs were detected in >70% of the samples, with a combined concentration of 17.0-484.7 ng/mL. Bayesian kernel machine regression analysis showed that exposure to the CEC mixture was significantly associated with a higher GDM risk. For example, when increasing all CECs in the mixture from 50th percentile to 75th percentile, the estimated probit of GDM incidence had an increase of 92% (95% CI: 56%, 127%). Meanwhile, perfluorohexanesulfonic acid, 1,3-diphenylguanidine, and dibutyl fumarate were identified as the key CECs driving the joint effect. This work demonstrates great potential of our target exposome protocol for environmental risk factor identification in large-scale epidemiology or biomonitoring studies.

Metabolic and oxidative stress response of sea cucumber Apostichopus japonicus exposed to acute high concentration of bisphenol AF

Bisphenols are known as endocrine disruptor that affect the development, and growth of marine creatures, including human. There were plenty of manuscripts evaluated the toxicology of bisphenol A (BPA) and its analogues such as bisphenol F (BPF), bisphenol AF (BPAF), and bisphenol S (BPS), but limits of them studied the effects of bisphenol analogues on echinoderms. In this study, we used metabolomics to investigate the metabolic response of sea cucumber (Apostichopus japonicus) exposed to BPAF, and the activities of glutathione (GSH), catalase (CAT), and superoxide dismutase (SOD) were determined. The results demonstrated alterations in lipid metabolism, glycerophospholipid metabolism, and biosynthesis of amino acids following BPAF treatment. Sea cucumbers upregulated the glycerophospholipid metabolism to repair the destruction of intestine cellular homeostasis. Six metabolites were selected as the potential biomarkers for the exposure of BPAF. This study revealed the metabolic response and oxidative response of sea cucumber arising from BPAF exposure, and provided theoretical support for the risk assessment of bisphenol analogues on economically important echinoderms, such as A. japonicus.

FTO-Nrf2 axis regulates bisphenol F-induced leydig cell toxicity in an m6A-YTHDF2-dependent manner

Studies have shown that Bisphenol F (BPF) as an emerging bisphenol pollutant also has caused many hazards to the reproductive systems of humans and animals. However, its specific mechanism is still unclear. The mouse TM3 Leydig cell was used to explore the mechanism of BPF-induced reproductive toxicity in this study. The results showed BPF (0, 20, 40 and 80 μM) exposure for 72 h significantly increased cell apoptosis and decreased cell viability. Correspondingly, BPF increased the expression of P53 and BAX, and decreased the expression of BCL2. Moreover, BPF significantly increased the intracellular ROS level in TM3 cells, and significantly decreased oxidative stress-related molecule Nrf2. BPF decreased the expression of FTO and YTHDF2, and increased the total cellular m6A level. ChIP results showed that AhR transcriptionally regulated FTO. Differential expression of FTO revealed that FTO reduced the apoptosis rate of BPF-exposed TM3 cells and increased the expression of Nrf2, MeRIP confirmed that overexpression of FTO reduced the m6A of Nrf2 mRNA. After differential expression of YTHDF2, it was found that YTHDF2 enhanced the stability of Nrf2, and RIP assay showed that YTHDF2 was bound to Nrf2 mRNA. Nrf2 agonist enhanced the protective effect of FTO on TM3 cells exposure to BPF. Our study is the first to demonstrate that AhR transcriptionally regulated FTO, and then FTO regulated Nrf2 in a m6A-modified manner through YTHDF2, thereby affecting apoptosis in BPF-exposed TM3 cells to induce reproductive damage. It provides new insights into the importance of FTO-YTHDF2-Nrf2 signaling axis in BPF-induced reproductive toxicity and provided a new idea for the prevention of male reproductive injury.

Oral exposure to tire rubber-derived contaminant 6PPD and 6PPD-quinone induce hepatotoxicity in mice

N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD) is a widely used additive for protecting various rubber products, and its product of oxidation N-(1,3-Dimethylbutyl)-N'-phenyl-p-phenylenediamine-quinone (6PPDQ) has attracted extensive attention in aquatic toxicity. However, the toxicity of 6PPD and 6PPDQ in mammals has not been reported yet. In this study, the effects of 6PPD and 6PPDQ on the liver of C57BL/6 mice were assessed by orally administering different doses of 6PPD and 6PPDQ (10, 30, and 100 mg/kg) in mice for 6 weeks. 6PPD and 6PPDQ were found to bioaccumulate in the liver in a dose-dependent manner. Moreover, a high dose of 6PPD and 6PPDQ exposure increased not only the liver weights but also liver triglyceride levels, indicating that 6PPD and 6PPDQ exposure induced hepatotoxicity in mice. Furthermore, transcriptomic analysis revealed that 6PPD and 6PPDQ induced differential expression of genes mainly enriched in glycolipid metabolism, immune-related, and glutathione metabolism pathways. Therefore, 6PPD and 6PPDQ altered hepatic metabolism in mice. Furthermore, 6PPDQ could induce an immune response by upregulating the transcription of immune-related genes and promoting macrophage infiltration in the liver. In conclusion, our study revealed the toxic effects of 6PPD and 6PPDQ exposure on multi-endpoints in the liver of mice and improve our understanding of the health risks of 6PPD and 6PPDQ to mammals. The findings of our study may help formulate better safety regulations for the use and disposal of rubber products.

Comparative pharyngeal cartilage developmental toxicity of bisphenol A, bisphenol S and bisphenol AF to zebrafish (Danio rerio) larvae: A combination of morphometry and global transcriptome analyses

Exposure to BPA is recently shown to affect cartilage development in teleost fishes; whether BPS and BPAF, its two most frequently used phenolic analogues have similar effect, however, remains unclear. Here, we utilize zebrafish (Danio rerio) as an in-vivo larval model for systematic comparison of the pharyngeal arch-derived cartilage developmental toxicity of BPA, BPS and BPAF. Zebrafish are continuously exposed to three bisphenol analogues (3-BPs) at a range of concentrations since the embryonic stage (0.5 hpf), and identified cartilage malformations of the mandibular and hyoid pharyngeal arches at larval stage (120 hpf). BPA and BPAF prolong length and broaden cartilage angles; however, BPS shortens length and narrows the angles of skull cartilages. The results of the comparative transcriptome show that FoxO and MAPK signaling pathways are closely associated with the toxicity of BPA and BPAF, while BPS exposure affects energy metabolism-related pathways. Moreover, exposure to 3-BPs have an impact on the oxidative stress status. Our data collectively indicate that BPS and BPAF may not be safer than BPA regarding the impact on pharyngeal cartilage development in fish model, the mechanisms still need explorations, and that these two analogues should be applied with caution.

Congener-Specific Uptake and Metabolism of Bisphenols in Carrot Cells: Dissipation Kinetics, Biotransformation, and Enzyme Responses

Food consumption has been considered a key pathway of bisphenol compound (BP) exposure for humans. However, there is a lack of evidence concerning their congener-specific behavior and metabolism in plants. Herein, we examined the uptake and metabolism of five BPs in plants using carrot cells. Bisphenol S (BPS) and bisphenol AF (BPAF) exhibited substantially lower dissipation rates in the cells than the other BPs, indicating a strong selectivity in the uptake and metabolism among bisphenol congeners. For a total of 23 metabolites of BPs, the predominant biotransformation pathways were found to be glycosylation, methoxylation, and conjugation, while hydroxylation, methylation, and glutathionylation were only observed for some BPs. The changes in the mRNA expression of cytochrome P450 (P450) and the activities of glycosyltransferase and glutathione S-transferase were remarkably higher in cells exposed to bisphenol F, bisphenol A, and bisphenol B than in cells exposed to BPS and BPAF, indicating congener specificity in their effects on enzymes and the associated biotransformation processes. Consequently, the potential congener-specific differences in plant uptake, metabolism, and accumulation must be considered when assessing the environmental risks posed by these commonly used plasticizers.

Exposure to bisphenol A and its analogs and polycystic ovarian syndrome in women of childbearing age: A multicenter case-control study

BACKGROUND/OBJECTIVES

In recent years, the reproductive toxicity of new bisphenol analogs has garnered much interest, but it remains to be determined whether bisphenol analogs affect polycystic ovarian syndrome (PCOS).

METHODS

This study utilized data from a multicenter hospital-based case-control study conducted in 2014-2016 to examine the association between endocrine-disrupting chemicals and infertility in China. 321 PCOS cases and 412 controls were included in the current analysis. We quantified seven bisphenol analogs in urine samples, including bisphenol A (BPA), bisphenol AP (BPAP), bisphenol AF (BPAF), bisphenol B (BPB), bisphenol S (BPS), bisphenol P (BPP), and bisphenol Z (BPZ). Spearman correlation and generalized linear regression were used in assessing the relationship between bisphenol analogs and hormonal parameters. To examine the association of bisphenol analogs with odds of PCOS, multiple logistic regression, and two multi-pollutant models [quantile-based g-computation (QGC) and extreme gradient boosting (XGBoost) methods] were used.

RESULTS

After covariates adjustment, BPA, BPS, and BPAF were positively correlated with testosterone (T) in the control group (P < 0.05). Dose-response relationships were discovered between BPA, BPS, BPZ, and BPAF quartiles and PCOS. Mixed exposure to seven bisphenol analogs was found to be positively associated with the odds of PCOS (adjusted odds ratio = 1.26; 1.12-1.45), which was primarily driven by BPS (weight = 0.51), BPZ (weight = 0.26), and BPAF (weight = 0.23). Women who were overweight or obese tended to have a stronger association between bisphenol analogs and PCOS than normal-weight women.

CONCLUSIONS

Environmental exposure to bisphenol analogs was associated with increased odds of PCOS in this case-control study. This association was stronger among obese and overweight women.

Bisphenol F induces liver-gut alteration in zebrafish

The unease of consumers with bisphenol A has led to the increased industrial usage of bisphenol F (BPF), which is a new hazard to environmental health. Here, zebrafish were exposed to three BPF concentrations (0.5, 5, and 50 μg/L) from the embryonic stage for 180 days. Results showed that zebrafish body length and weight decreased and hepatosomatic index values increased, even at environmentally relevant concentration. Histological analysis identified the occurrence of hepatic fibrosis and steatosis in 5 and 50 μg/L groups, which indicated the liver injury caused by BPF. Based on the untargeted metabolomics results, a dose-dependent variation in the effects of BPF on liver metabolism was found, and amino acids, purines and one carbon metabolism were the main affected processes in the 0.5, 5, and 50 μg/L treatments, respectively. At the same time, BPF induced a shift in intestinal microbiome composition, including decreased abundance of Erysipelotrichaceae, Rhodobacteraceae and Gemmobacter. In addition, the correlation analysis suggested an association between gut microbiome changes and affected hepatic metabolites after BPF exposure. These findings indicate that a liver-gut alteration is induced by long-term BPF exposure.

Developmental and Reproductive Impacts of Four Bisphenols in Daphnia magna

Bisphenol A (BPA) is a typical endocrine-disrupting chemical (EDC) used worldwide. Considering its adverse effects, BPA has been banned or strictly restricted in some nations, and many analogs have been introduced to the market. In this study, we selected three representative substitutes, BPS, BPF, and BPAF, along with BPA, to assess the developmental and reproductive effects on Daphnia magna. The F0 generation was exposed to bisphenols (BPs) at an environmentally relevant concentration (100 μg/L) for 21 d; then the embryo spawn at day 21 was collected. Behavior traits, the activity of antioxidant enzymes, and gene transcription were evaluated at three developmental stages (days 7, 14, and 21). Notably, body length, heart rate, and thoracic limb beating were significantly decreased, and D. magna behaved more sluggishly in the exposed group. Moreover, exposure to BPs significantly increased the antioxidant enzymatic activities, which indicated that BPs activated the antioxidant defense system. Additionally, gene expression indicated intergenerational effects in larvae, particularly in the BPAF group. In conclusion, BPA analogs such as BPF and BPAF showed similar or stronger reproductive and developmental toxicity than BPA in D. magna. These findings collectively deepen our understanding of the toxicity of BPA analogs and provide empirical evidence for screening safe alternatives to BPA.