The environmental obesogen bisphenol A promotes adipogenesis by increasing the amount of 11β-hydroxysteroid dehydrogenase type 1 in the adipose tissue of children

Establishments of G3BP1-GFP stress granule monitoring system for real-time stress assessment in human neuroblastoma cells

Acute stress caused by short-term exposure to deleterious chemicals can induce the aggregation of RNA-binding proteins (RBPs) in the cytosol and the formation of stress granules (SGs). The cytoplasmic RBP, Ras GTPase-activating protein-binding protein 1 (G3BP1) is a critical organizer of SG, and its aggregation is considered a hallmark of cellular stress. However, assembly of SG is a highly dynamic process that involves RBPs; hence, existing methods based on fixation processes or overexpression of RBPs exhibit limited efficacy in detecting the assembly of SG under stress conditions. In this study, we established a G3BP1- Green fluorescent protein (GFP) reporter protein in a human neuroblastoma cell line to overcome these limitations. GFP was introduced into the G3BP1 genomic sequence via homologous recombination to generate a G3BP1-GFP fusion protein and further analyze the aggregation processes. We validated the assembly of SG under stress conditions using the G3BP1-GFP reporter system. Additionally, this system supported the evaluation of bisphenol A-induced SG response in the established human neuroblastoma cell line. In conclusion, the established G3BP1-GFP reporter system enables us to monitor the assembly of the SG complex in a human neuroblastoma cell line in real time and can serve as an efficient tool for assessing potential neurotoxicity associated with short-term exposure to chemicals.

Exploring novel insights into the molecular mechanisms underlying Bisphenol A-induced toxicity: A persistent threat to human health

Bisphenol A (BPA) is a ubiquitous industrial chemical used in the production of polycarbonate plastics and epoxy resins, found in numerous consumer products. Despite its widespread use, its potential adverse health effects have raised significant concerns. This review explores the molecular mechanisms and evidence-based literature underlying BPA-induced toxicities and its implications for human health. BPA is an endocrine-disrupting chemical (EDC) which exhibits carcinogenic properties by influencing various receptors, such as ER, AhR, PPARs, LXRs, and RARs. It induces oxidative stress and contributes to cellular dysfunction, inflammation, and DNA damage, ultimately leading to various toxicities including but not limited to reproductive, cardiotoxicity, neurotoxicity, and endocrine toxicity. Moreover, BPA can modify DNA methylation patterns, histone modifications, and non-coding RNA expression, leading to epigenetic changes and contribute to carcinogenesis. Overall, understanding molecular mechanisms of BPA-induced toxicity is crucial for developing effective strategies and policies to mitigate its adverse effects on human health.

The Role of Endocrine Disruptors Bisphenols and Phthalates in Obesity: Current Evidence, Perspectives and Controversies

Excess body weight constitutes one of the major health challenges for societies and healthcare systems worldwide. Besides the type of diet, calorie intake and the lack of physical exercise, recent data have highlighted a possible association between endocrine-disrupting chemicals (EDCs), such as bisphenol A, phthalates and their analogs, and obesity. EDCs represent a heterogeneous group of chemicals that may influence the hormonal regulation of body mass and adipose tissue morphology. Based on the available data from mechanistic, animal and epidemiological studies including meta-analyses, the weight of evidence points towards the contribution of EDCs to the development of obesity, associated disorders and obesity-related adipose tissue dysfunction by (1) impacting adipogenesis; (2) modulating epigenetic pathways during development, enhancing susceptibility to obesity; (3) influencing neuroendocrine signals responsible for appetite and satiety; (4) promoting a proinflammatory milieu in adipose tissue and inducing a state of chronic subclinical inflammation; (5) dysregulating gut microbiome and immune homeostasis; and (6) inducing dysfunction in thermogenic adipose tissue. Critical periods of exposure to obesogenic EDCs are the prenatal, neonatal, pubertal and reproductive periods. Interestingly, EDCs even at low doses may promote epigenetic transgenerational inheritance of adult obesity in subsequent generations. The aim of this review is to summarize the available evidence on the role of obesogenic EDCs, specifically BPA and phthalate plasticizers, in the development of obesity, taking into account in vitro, animal and epidemiologic studies; discuss mechanisms linking EDCs to obesity; analyze the effects of EDCs on obesity in critical chronic periods of exposure; and present interesting perspectives, challenges and preventive measures in this research area.

Bisphenol A (BPA) and Cardiovascular or Cardiometabolic Diseases

Bisphenol A (BPA; 4,4'-isopropylidenediphenol) is a well-known endocrine disruptor. Most human exposure to BPA occurs through the consumption of BPA-contaminated foods. Cardiovascular or cardiometabolic diseases such as diabetes, obesity, hypertension, acute kidney disease, chronic kidney disease, and heart failure are the leading causes of death worldwide. Positive associations have been reported between blood or urinary BPA levels and cardiovascular or cardiometabolic diseases. BPA also induces disorders or dysfunctions in the tissues associated with these diseases through various cell signaling pathways. This review highlights the literature elucidating the relationship between BPA and various cardiovascular or cardiometabolic diseases and the potential mechanisms underlying BPA-mediated disorders or dysfunctions in tissues such as blood vessels, skeletal muscle, adipose tissue, liver, pancreas, kidney, and heart that are associated with these diseases.

From gestational chronodisruption to noncommunicable diseases: Pathophysiological mechanisms of programming of adult diseases, and the potential therapeutic role of melatonin

During gestation, the developing fetus relies on precise maternal circadian signals for optimal growth and preparation for extrauterine life. These signals regulate the daily delivery of oxygen, nutrients, hormones, and other biophysical factors while synchronizing fetal rhythms with the external photoperiod. However, modern lifestyle factors such as light pollution and shift work can induce gestational chronodisruption, leading to the desynchronization of maternal and fetal circadian rhythms. Such disruptions have been associated with adverse effects on cardiovascular, neurodevelopmental, metabolic, and endocrine functions in the fetus, increasing the susceptibility to noncommunicable diseases (NCDs) in adult life. This aligns with the Developmental Origins of Health and Disease theory, suggesting that early-life exposures can significantly influence health outcomes later in life. The consequences of gestational chronodisruption also extend into adulthood. Environmental factors like diet and stress can exacerbate the adverse effects of these disruptions, underscoring the importance of maintaining a healthy circadian rhythm across the lifespan to prevent NCDs and mitigate the impact of gestational chronodisruption on aging. Research efforts are currently aimed at identifying potential interventions to prevent or mitigate the effects of gestational chronodisruption. Melatonin supplementation during pregnancy emerges as a promising intervention, although further investigation is required to fully understand the precise mechanisms involved and to develop effective strategies for promoting health and preventing NCDs in individuals affected by gestational chronodisruption.

Environmental Pollution and the Risk of Developing Metabolic Disorders: Obesity and Diabetes

To meet the increased need for food and energy because of the economic shift brought about by the Industrial Revolution in the 19th century, there has been an increase in persistent organic pollutants (POPs), atmospheric emissions and metals in the environment. Several studies have reported a relationship between these pollutants and obesity, and diabetes (type 1, type 2 and gestational). All of the major pollutants are considered to be endocrine disruptors because of their interactions with various transcription factors, receptors and tissues that result in alterations of metabolic function. POPs impact adipogenesis, thereby increasing the prevalence of obesity in exposed individuals. Metals impact glucose regulation by disrupting pancreatic β-cells, causing hyperglycemia and impaired insulin signaling. Additionally, a positive association has been observed between the concentration of endocrine disrupting chemicals (EDCs) in the 12 weeks prior to conception and fasting glucose levels. Here, we evaluate what is currently known regarding the link between environmental pollutants and metabolic disorders. In addition, we indicate where further research is required to improve our understanding of the specific effects of pollutants on these metabolic disorders which would enable implementation of changes to enable their prevention.

Application of In Vitro Models for Studying the Mechanisms Underlying the Obesogenic Action of Endocrine-Disrupting Chemicals (EDCs) as Food Contaminants-A Review

Obesogenic endocrine-disrupting chemicals (EDCs) belong to the group of environmental contaminants, which can adversely affect human health. A growing body of evidence supports that chronic exposure to EDCs can contribute to a rapid increase in obesity among adults and children, especially in wealthy industrialized countries with a high production of widely used industrial chemicals such as plasticizers (bisphenols and phthalates), parabens, flame retardants, and pesticides. The main source of human exposure to obesogenic EDCs is through diet, particularly with the consumption of contaminated food such as meat, fish, fruit, vegetables, milk, and dairy products. EDCs can promote obesity by stimulating adipo- and lipogenesis of target cells such as adipocytes and hepatocytes, disrupting glucose metabolism and insulin secretion, and impacting hormonal appetite/satiety regulation. In vitro models still play an essential role in investigating potential environmental obesogens. The review aimed to provide information on currently available two-dimensional (2D) in vitro animal and human cell models applied for studying the mechanisms of obesogenic action of various industrial chemicals such as food contaminants. The advantages and limitations of in vitro models representing the crucial endocrine tissue (adipose tissue) and organs (liver and pancreas) involved in the etiology of obesity and metabolic diseases, which are applied to evaluate the effects of obesogenic EDCs and their disruption activity, were thoroughly and critically discussed.

Impact of combined chronic exposure to low-dose bisphenol A and fructose on serum adipocytokines and the energy target metabolome in white adipose tissue

Background: Adipose tissue is a dynamic endocrine organ that plays a key role in regulating metabolic homeostasis. Previous studies confirmed that bisphenol A (BPA) or fructose can interfere with the function of adipose tissue. Nonetheless, knowledge on how exposure to BPA and fructose impacts energy metabolism in adipose tissue remains limited.Purpose: To determine impact of combined chronic exposure to low-dose bisphenol A and fructose on serum adipocytokines and the energy target metabolome in white adipose tissue.Method: 57 energy metabolic intermediates in adipose tissue and 7 adipocytokines in serum from Sprague Dawley rats were examined after combined exposure to two levels of BPA (lower dose: 0.25, and higher dose: 25 μg/kg every other day) and 5% fructose for 6 months.Results: combined exposure to lower-dose BPA and fructose significantly increased omentin-1, pyruvic acid, adenosine triphosphate (ATP), adenosine monophosphate (AMP), inosine monophosphate (IMP), inosine, and l-lactate; however, these parameters were not significantly affected by higher-dose BPA combined with fructose. Interestingly, the level of succinate (an intermediate of the citric acid cycle) increased dose-dependently in adipose tissue, and the level of apelin 13 (a versatile adipocytokine) decreased dose-dependently in serum after combined exposure to BPA and fructose. Phosphoenolpyruvic acid, phenyl-lactate, and ornithine were significantly correlated with asprosin, omentin-1, apelin, apelin 13, and adiponectin, while l-tyrosine was significantly correlated with irisin and a-FABP under combined exposure to BPA and fructose.Conclusions: these findings indicated that lower-dose BPA combined with fructose could amplify the impact on glycolysis, energy storage, and purine nucleotide biosynthesis in adipose tissue, and adipocytokines, such as omentin-1 and apelin 13, may be related to metabolic interference induced by BPA and fructose exposure.

Bisphenol A is a carcinogen that induces lipid accumulation, peroxisome proliferator‑activated receptor‑γ expression and liver disease

Bisphenol (BP) A is an exogenous endocrine disruptor that mimics hormones closely associated with health complications, e.g., obesity and cancers. The present study aimed to evaluate the effects of BPA on human liver cells and tissue. The peroxisome proliferator-activated receptor (PPAR)-γ expression profile across tumour samples and paired normal tissue was first analysed using GEPIA. Subsequently, BPA-treated liver THLE-2 cell viability was evaluated using an MTT assay. Clusterin, PPARα and PPARγ gene expression in BPA-treated THLE-2 cells was assessed using GEPIA before validating the gene expression using real-time PCR and analysing overall survival using TCGA data in GEPIA. Cytoplasmic lipid accumulation was examined in BPA-treated THLE-2 cells using Oil Red O staining, and liver tissue was examined using haematoxylin and eosin staining. Finally, cytochrome P450 (CYP) gene expression was assessed in BPA-treated THLE-2 cells using real-time PCR. PPARγ is likely the primary nuclear receptor protein involved in lipid accumulation in THLE-2 cells following BPA treatment and is associated with liver disease. THLE-2 cells exposed to BPA showed a decrease in viability and lipid accumulation after 48 h treatment. Higher PPARγ gene expression was significantly associated with survival of patients with liver cancer, with an average survival time of <80 months. Haematoxylin and eosin-stained sections showed notable disruption of the liver architecture in tissue exposed to BPA. Downregulated CYP1A1 and CYP1B1 gene expression implied that BPA-treated THLE-2 cells decreased capacity for carcinogen metabolism, while upregulated CYP2S1 gene expression exerted minimal cytotoxicity. The present study revealed that BPA served as a carcinogen, enhanced tumorigenesis susceptibility and may induce other types of liver disease.

Implications of endocrine-disrupting chemicals on polycystic ovarian syndrome: A comprehensive review

Polycystic ovarian syndrome (PCOS) is a complex multifactorial disorder of unknown pathogenesis in which genetic and environmental factors contribute synergistically to its phenotypic expressions. Endocrine-disrupting chemicals (EDCs), a group of widespread pollutants freely available in the environment and consumer products, can interfere with normal endocrine signals. Extensive evidence has shown that EDCs, environmental contributors to PCOS, can frequently induce ovarian and metabolic abnormalities at low doses. The current research on environmental EDCs suggests that there may be link between EDC exposure and PCOS, which calls for more human bio-monitoring of EDCs using highly sophisticated analytical techniques for the identification and quantification and to discover the underlying pathophysiology of the disease. This review briefly elaborated on the general etiology of PCOS and listed various epidemiological and experimental data from human and animal studies correlating EDCs and PCOS. This review also provides insights into various analytical tools and sample preparation techniques for biomonitoring studies for PCOS risk assessment. Furthermore, we highlight the role of metabolomics in disease-specific biomarker discovery and its use in clinical practice. It also suggests the way forward to integrate biomonitoring studies and metabolomics to underpin the role of EDCs in PCOS pathophysiology.

The Mixture of Bisphenol-A and Its Substitutes Bisphenol-S and Bisphenol-F Exerts Obesogenic Activity on Human Adipose-Derived Stem Cells

Bisphenol A (BPA) and its substitutes, bisphenol F (BPF) and S (BPS), have previously shown in vitro obesogenic activity. This study was designed to investigate their combined effect on the adipogenic differentiation of human adipose-derived stem cells (hASCs). Cells were exposed for 14 days to an equimolar mixture of bisphenols (MIX) (range 10 nM–10 µM). Oil Red staining was used to measure intracellular lipid accumulation, quantitative real-time polymerase chain reaction (qRT-PCR) to study gene expression of adipogenic markers (PPARγ, C/EBPα, LPL, and FABP4), and Western Blot to determine their corresponding proteins. The MIX promoted intracellular lipid accumulation in a dose-dependent manner with a maximal response at 10 µM. Co-incubation with pure antiestrogen (ICI 182,780) inhibited lipid accumulation, suggesting that the effect was mediated by the estrogen receptor. The MIX also significantly altered the expression of PPARγ, C/EBPα, LPL, and FABP4 markers, observing a non-monotonic (U-shaped) dose-response, with maximal gene expression at 10 nM and 10 µM and lesser expression at 1 µM. This pattern was not observed when bisphenols were tested individually. Exposure to MIX (1–10 µM) also increased all encoded proteins except for FABP4, which showed no changes. Evaluation of the combined effect of relevant chemical mixtures is needed rather than single chemical testing.

Does Bisphenol A Confer Risk of Neurodevelopmental Disorders? What We Have Learned from Developmental Neurotoxicity Studies in Animal Models

Substantial evidence indicates that bisphenol A (BPA), a ubiquitous environmental chemical used in the synthesis of polycarbonate plastics and epoxy resins, can impair brain development. Clinical and epidemiological studies exploring potential connections between BPA and neurodevelopmental disorders in humans have repeatedly identified correlations between early BPA exposure and developmental disorders, such as attention deficit/hyperactivity disorder and autism spectrum disorder. Investigations using invertebrate and vertebrate animal models have revealed that developmental exposure to BPA can impair multiple aspects of neuronal development, including neural stem cell proliferation and differentiation, synapse formation, and synaptic plasticity-neuronal phenotypes that are thought to underpin the fundamental changes in behavior-associated neurodevelopmental disorders. Consistent with neuronal phenotypes caused by BPA, behavioral analyses of BPA-treated animals have shown significant impacts on behavioral endophenotypes related to neurodevelopmental disorders, including altered locomotor activity, learning and memory deficits, and anxiety-like behavior. To contextualize the correlations between BPA and neurodevelopmental disorders in humans, this review summarizes the current literature on the developmental neurotoxicity of BPA in laboratory animals with an emphasis on neuronal phenotypes, molecular mechanisms, and behavioral outcomes. The collective works described here predominantly support the notion that gestational exposure to BPA should be regarded as a risk factor for neurodevelopmental disorders.

The Role of Persistent Organic Pollutants in Obesity: A Review of Laboratory and Epidemiological Studies

Persistent organic pollutants (POPs) are considered as potential obesogens that may affect adipose tissue development and functioning, thus promoting obesity. However, various POPs may have different mechanisms of action. The objective of the present review is to discuss the key mechanisms linking exposure to POPs to adipose tissue dysfunction and obesity. Laboratory data clearly demonstrate that the mechanisms associated with the interference of exposure to POPs with obesity include: (a) dysregulation of adipogenesis regulators (PPARγ and C/EBPα); (b) affinity and binding to nuclear receptors; (c) epigenetic effects; and/or (d) proinflammatory activity. Although in vivo data are generally corroborative of the in vitro results, studies in living organisms have shown that the impact of POPs on adipogenesis is affected by biological factors such as sex, age, and period of exposure. Epidemiological data demonstrate a significant association between exposure to POPs and obesity and obesity-associated metabolic disturbances (e.g., type 2 diabetes mellitus and metabolic syndrome), although the existing data are considered insufficient. In conclusion, both laboratory and epidemiological data underline the significant role of POPs as environmental obesogens. However, further studies are required to better characterize both the mechanisms and the dose/concentration-response effects of exposure to POPs in the development of obesity and other metabolic diseases.

Bisphenol A and its alternatives in Austrian thermal paper receipts, and the migration from reusable plastic drinking bottles into water and artificial saliva using UHPLC-MS/MS

Bisphenol A (BPA) a synthetic, high production volume chemical identified as endocrine disruptor and toxic to reproduction is mainly used in the production of polycarbonate plastics, in epoxy resins, polyvinylchloride, thermal papers as color developer, and is present in a wide range of consumer goods such as food packaging materials, storage containers, and cash receipts. Due to its effects on health and legal restrictions, BPA is increasingly replaced by other bisphenols. In this study, BPA and 13 alternatives including BPS, Bisphenol F (BPF), Bisphenol B (BPB), Bisphenol C (BPC), Bisphenol Z (BPZ), Bisphenol M (BPM), Bisphenol P (BPP), Bisphenol AF (BPAF), Bisphenol FL (BPFL), Bisphenol C12 (BPC12), Tetramethylbisphenol A (tmBPA), 4,4-bisphenol (BP-4,4), and p,p-oxybisphenol were analyzed in thermal paper cash receipts (content) and migration studies were carried out in BPA-free labelled reusable plastic drinking bottles using a sensitive UHPLC-MS/MS method. The receipts contained almost only BPA and BPS, whereas BPS was found in all samples ranging at levels up to 38 μg/g. BPA was detected at low concentrations, only in one sample 11,000 μg/g were found, exceeding the EU limit of BPA in thermal paper of 0.02% per weight. In leaching solutions from the drinking bottles BPA, BPS and BPF were found at concentrations up to 0.047 μg/L BPA, 0.043 μg/L BPS, and <0.01 μg/L BPF. No other analogues were detected. However, these levels identified are far below the legal limits. In addition, a theoretical exposure assessment was conducted indicating that exposures were within the current regulatory guidelines.

Endrin potentiates early-stage adipogenesis in 3T3-L1 cells by activating the mammalian target of rapamycin

Obesogens are a type of endocrine-disrupting chemicals (EDCs) that disrupt the human endocrine system, resulting in obesity and metabolic disease. Several obesogens, including bisphenol A, tolylfluanid, and some pesticides, have been identified and studied previously; however, the underlying molecular mechanisms by which obesogens interfere with adipogenesis and induce insulin resistance in adipocyte remain unknown. This study aims to determine which type of chemical is the most potent obesogen and to investigate its effect on adipogenesis-related gene expressions. 3T3-L1, a pre adipocyte cell line, was differentiated into mature adipocytes with either vehicle or various obesogens, including bisphenol A, tolylfluanid, and endrin, as well as corticosterone, at the same dose. Subsequently, intracellular and secreted triglyceride levels were measured, and the expression of genes and proteins involved in adipogenesis and lipogenesis was investigated. We found that endrin was the most potent regulator of adipogenic differentiation, as compared to tolylfluanid, bisphenol A, and corticosterone. Endrin increased intracellular and secreted triglyceride levels and enhanced the expression of adipogenic transcription factors as well as the terminal differentiation marker in a dose-dependent manner. During the early stages of differentiation, endrin enhanced mammalian target of rapamycin (mTOR) activity, which was suppressed by the pharmacological blockade of the protein kinase B-mTOR pathway, with repressed adipogenic differentiation. However, endrin did not change the expression levels of the downstream members of the mTOR signaling pathway or proteins related to lipolysis in response to insulin. Thus, we suggest that endrin potentiates early-stage adipogenic differentiation by activating the mTOR pathway.

Obesogens in Children-An Uncharted Territory

Obesogens are exogenous chemicals belonging to the group of endocrine-disrupting chemicals and are believed to interfere in obesity development. In children, several chemicals are under investigation, most commonly bisphenol A, phthalates, perfluorinated alkyl substances, and persistent organic pollutants, including organochlorinated pesticides, tributyltin, polychlorinated biphenyls and dioxins. Several associations have been studied between chemical exposure in utero and postnatally. Current opinion among researchers indicates that the obesogen theory is very likely; however, limited published studies show inconsistent support for the obesogenic effects of most substances in children and are limited by difficulty in providing the exact mechanisms of action, nor is their mutual effect in humans known, let alone in children. Existing data indicate that we have only scratched the surface and have much more to learn about obesogens. Hopefully, in the future, more information will provide an opportunity for policy makers to take action and protect public health.

Occurrence, spatial distribution and risk assessment of high concern endocrine-disrupting chemicals in Jiangsu Province, China

Endocrine-disrupting chemicals (EDCs) have attracted much concern because of the environmental and health risks they pose. Here we used liquid chromatography coupled with quadrupole-Orbitrap high-resolution mass spectrometry to quantify 10 types of EDCs at 118 sampling sites in Jiangsu Province, China, and then evaluated their respective environmental risk using a conservative risk quotient method. The results show that, in surface water, the targeted nonylphenol (NP), 4-tert-octylphenol (4-t-OP), and (2-ethylhexyl)phthalate (DEHP) were ranked highest, having mean concentrations above 300 ng/L. In comparison, both 4-t-OP and DEHP were also ranked highest, with mean concentrations above 100 ng/g, in the sediment samples. Moreover, the ∑₁₀EDCs concentration in the Huai River Basin was similar to that in the Yangtze River Basin. Notably, Huai'an city had the maximum mean concentration for EDCs in the Huai River Basin, followed by Xuzhou city and Suqian city, while Yangzhou city ranked highest in the Yangtze River Basin. Furthermore, the corresponding risk distribution revealed that (1) NP, bisphenol A (BPA), and 4-t-OP are of medium to high risk in 70%, 100% and 95% of the surface water samples, and likewise in 45%, 88% and 100% of the sediment samples, respectively; the maximum RQ value for NP in surface water samples reached 74.9; (2) DEHP belongs to the high-risk category in all samples (100%), whose maximum RQ reached 54.7. To our best knowledge, this is the first study to report on the occurrence, spatial distribution, and risk assessment of EDCs of high concern in Jiangsu Province, China.

Epigenetic Mechanisms of Endocrine-Disrupting Chemicals in Obesity

The incidence of obesity has dramatically increased over the last decades. Recently, there has been a growing interest in the possible association between the pandemics of obesity and some endocrine-disrupting chemicals (EDCs), termed “obesogens”. These are a heterogeneous group of exogenous compounds that can interfere in the endocrine regulation of energy metabolism and adipose tissue structure. Oral intake, inhalation, and dermal absorption represent the major sources of human exposure to these EDCs. Recently, epigenetic changes such as the methylation of cytosine residues on DNA, post-translational modification of histones, and microRNA expression have been considered to act as an intermediary between deleterious effects of EDCs and obesity development in susceptible individuals. Specifically, EDCs exposure during early-life development can detrimentally affect individuals via inducing epigenetic modifications that can permanently change the epigenome in the germline, enabling changes to be transmitted to the next generations and predisposing them to a multitude of diseases. The purpose of this review is to analyze the epigenetic alterations putatively induced by chemical exposures and their ability to interfere with the control of energy metabolism and adipose tissue regulation, resulting in imbalances in the control of body weight, which can lead to obesity.

Bisphenols and the Development of Type 2 Diabetes: The Role of the Skeletal Muscle and Adipose Tissue

Bisphenol A (BPA) and bisphenol S (BPS) are environmental contaminants that have been associated with the development of insulin resistance and type 2 diabetes (T2D). Two organs that are often implicated in the development of insulin resistance are the skeletal muscle and the adipose tissue, however, seldom studies have investigated the effects of bisphenols on their metabolism. In this review we discuss metabolic perturbations that occur in both the skeletal muscle and adipose tissue affected with insulin resistance, and how exposure to BPA or BPS has been linked to these changes. Furthermore, we highlight the possible effects of BPA on the cross-talk between the skeletal muscle and adipose tissue.

Bisphenol F and bisphenol S promote lipid accumulation and adipogenesis in human adipose-derived stem cells

Bisphenol F (BPF) and bisphenol S (BPS) are increasingly used as substitutes for bisphenol A (BPA), an endocrine disrupting chemical (EDC) with obesogenic activity. We investigated the in vitro effects of BPS and BPF on the adipogenesis of human adipose-derived stem cells (hASCs) exposed to different doses (0.01, 0.1, 1, 10 and 25 μM), stopping the adipogenic process at 7 or 14 days. Intracellular lipid accumulation was quantified by the Oil Red O assay, gene expression of peroxisome proliferator-activated receptor gamma (PPARγ), CCAT/enhancer-binding protein (C/EBPα), lipoprotein-lipase (LPL) and fatty acid binding protein 4 (FABP4), by quantitative real-time polymerase chain reaction (qRT-PCR) and protein levels by Western Blot. hASCs with BPF or BPS produced a linear dose-response increase in intracellular lipid accumulation and in gene expression of the adipogenic markers, confirmed by protein levels. Co-treatment ICI 182,780 significantly inhibited BPF- but not BPS-induced lipid accumulation. Given the affinity of bisphenols for diverse nuclear receptors, their obesogenic effects may result from a combination of pathways rather than a single mechanism. Further research is warranted on the manner in which chemicals interfere with adipogenic differentiation. To our best knowledge, this report shows for the first time the obesogenic potential of BPF in hASCs.

Gestational bisphenol A exposure induces fatty liver development in male offspring mice through the inhibition of HNF1b and upregulation of PPARγ

Bisphenol A (BPA) is an endocrine-disrupting chemical (EDC) associated with non-alcoholic fatty liver disease (NAFLD). The effects of gestational BPA exposure on hepatic lipid accumulation in offspring are not fully understood. Here, we investigate the sex-dependent effects of gestational BPA exposure on hepatic lipid and glucose metabolism in the offspring of mice to reveal the mechanisms underlying gestational BPA exposure-associated NAFLD. Pregnant mice were administered gavage with or without 1 μg kg-1 day-1 BPA at embryonic day 7.5 (E7.5)-E16.5. Hepatic glucose and lipid metabolism were evaluated in these models. Both male and female offspring mice exhibited hepatic fatty liver after BPA treatment. Lipid accumulation and dysfunction of glucose metabolism were observed in male offspring. We revealed abnormal expression of lipid regulators in the liver and that inhibition of peroxisome proliferator-activated receptor γ (PPARγ) repressed hepatic lipid accumulation induced by gestational BPA exposure. We also found a sex-dependent decrease of hepatocyte nuclear factor 1b (HNF1b) expression in male offspring. The transcriptional repression of PPARγ by HNF1b was confirmed in L02 cells. Downregulation of HNF1b, upregulation of PPARγ, and subsequent upregulation of hepatic lipid accumulation were essential for NAFLD development in male offspring gestationally exposed to BPA as well as BPA-exposed adult male mice. Dysregulation of the HNF1b/PPARγ pathway may be involved in gestational BPA exposure-induced NAFLD in male offspring. These data provide new insights into the mechanism of gestational BPA exposure-associated sex-dependent glucose and lipid metabolic dysfunction. Graphical abstract Schematic of the mechanism of gestational BPA exposure-induced glucose and lipid metabolic dysfunction.

Serum levels of non-persistent environmental pollutants and risk of incident hypertension in a sub-cohort from the EPIC study

BACKGROUND

The prevalence of arterial hypertension (AHT), a well-known risk factor for cardiovascular disease, has considerably increased over last decades. Non-persistent environmental pollutants (npEPs) are a group of ubiquitous chemicals, widely used in consumer products such as food packaging and cosmetics, which have been identified as endocrine disrupting chemicals and obesogens. The aim of this study was to assess the potential associations of serum levels of three groups of npEPs with the risk of incident AHT.

METHODS

Cohort study within a sub-cohort of Granada EPIC-Spain center (n = 670). We quantified serum concentrations of three groups of npEPs, i.e., bisphenol A (BPA), four parabens: methylparaben (MP), ethylparaben (EP), propylparaben (PP) and butylparaben (BP), and two benzophenones: benzophenone 1 (BP1), benzophenone 3 (BP3), in samples collected at recruitment. Statistical analyses were performed by means of Cox Proportional Hazard Models.

RESULTS

Median follow-up time was 23 years. BPA and MP were found in >80% of the study population. Individuals within the 4th PP quartile (0.53-9.24 ng/ml) showed a statistically significant increased risk of AHT (HR = 1.40, p = 0.015). No associations were found for the rest of pollutants.

CONCLUSIONS

Overall, we evidenced no associations of most npEPs with AHT risk, with the exception of an increased risk in the highest PP percentiles. Considering the limitations of using one spot serum sample for exposure characterization, further research on the potential contribution of npEPs on the development of AHT risk is warranted.

Bisphenol A Induces Agrp Gene Expression in Hypothalamic Neurons through a Mechanism Involving ATF3

BACKGROUND

Bisphenol A (BPA) is a ubiquitous endocrine disrupting chemical and obesogen. Although limited evidence exists of the effects of BPA on hypothalamic agouti-related peptide (AgRP) levels, the mechanisms underlying these effects remain unknown. Given that AgRP is a potent orexigenic neuropeptide, determining the mechanism by which BPA increases AgRP is critical to preventing the progression to metabolic disease.

METHODS

Using quantitative reverse transcriptase polymerase chain reaction, we investigated the response of Agrp-expressing mouse hypothalamic cell lines to BPA treatment. The percentage of total BPA entering hypothalamic cells in culture was quantified using an enzyme-linked immunosorbent assay. In order to identify the mechanism underlying BPA-mediated changes in Agrp, siRNA knockdown of transcription factors, FOXO1, CHOP, ATF3, ATF4, ATF6, and small-molecule inhibitors of endoplasmic reticulum stress, JNK or MEK/ERK were used.

RESULTS

BPA increased mRNA levels of Agrp in six hypothalamic cell lines (mHypoA-59, mHypoE-41, mHypoA-2/12, mHypoE-46, mHypoE-44, and mHypoE-42). Interestingly, only 18% of the total BPA in the culture medium entered the cells after 24 h, suggesting that the exposure concentration is much lower than the treatment concentration. BPA increased pre-Agrp mRNA levels, indicating increased Agrp transcription. Knockdown of the transcription factor ATF3 prevented BPA-mediated increase in Agrp, pre-Agrp, and in part Npy mRNA levels. However, chemical chaperone, sodium phenylbutyrate, JNK inhibitor, SP600125, or the MEK/ERK inhibitor PD0352901 did not block BPA-induced Agrp upregulation.

CONCLUSION

Overall, these results indicate that hypothalamic Agrp is susceptible to dysregulation by BPA and implicate ATF3 as a common mediator of the orexigenic effects of BPA in hypothalamic neurons.

The effects of bisphenol A and bisphenol S on adipokine expression and glucose metabolism in human adipose tissue

PURPOSE

The environmental endocrine disruptors, bisphenol A (BPA) and bisphenol S (BPS) are associated with the development of type 2 diabetes. We aim to study the effects of BPA or BPS exposure on adipokine expression in human adipose tissue and on adipocyte glucose uptake.

METHODS

Human subcutaneous adipose tissue was treated for 24 or 72 h with environmentally-relevant and supraphysiological concentrations of BPA or BPS (1-10⁴ nM). Following exposure, gene expression of proinflammatory cytokines, adipokines, and estrogen receptors was measured in adipose tissue. Glucose uptake and the insulin signalling pathway were analyzed in isolated adipocytes following adipose tissue culture with BPA for 24 h.

RESULTS

Adipose tissue treated with BPA for 24 h had reduced expression of the proinflammatory genes (IL6, IL1B, TNFA) and adipokines (ADIPOQ, FABP4). BPA and BPS had no effect on the expression of other proinflammatory genes (IL33), adipokines (LEP), or receptors (ESR1, ESR2) after 72-h exposure. Adipose tissue treated with environmentally-relevant concentrations of BPA for 24 h had reduced insulin-stimulated glucose uptake, without altered gene and protein levels of key insulin signalling pathway markers.

CONCLUSIONS

We found that human adipose tissue treated with environmentally-relevant concentrations of BPA for 24 h, but not BPS, reduced expression of proinflammatory genes and adipokines. Furthermore, BPA reduced glucose uptake in adipocytes independently of insulin signalling. Such mechanisms can contribute to the development of insulin resistance associated with BPA exposure.

Bisphenol-A and polycystic ovary syndrome: a review of the literature

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder among women of reproductive age with reproductive, metabolic and endocrine implications. While the exact pathophysiological mechanisms of the syndrome are unknown, its heterogeneity suggests a multifactorial causal background. In the last two decades, numerous environmental chemicals, including Bisphenol-A (BPA) that is used in the synthesis of polycarbonate plastics, have been proposed as potential contributors to the aetiology of PCOS. This review provides a holistic overview of the available data regarding the possible relation of PCOS with BPA exposure. We have included a total number of 24 studies. Eleven human case-control and 13 animal studies provided data regarding this potential relation. Accumulating evidence suggests that a correlation between high levels of BPA and the presence of PCOS may exist. Contradicting results from human and animal studies, however, render it difficult to conclude on the exact role of BPA in the pathogenesis of PCOS. BPA may constitute a consequence of the syndrome rather than a cause, but further research is still needed to clarify this. Continued efforts to study the early origins of PCOS, using prospective-designed studies, are required to identify the exact effect of BPA on women with PCOS.

Low-dose Bisphenol-A Promotes Epigenetic Changes at Pparγ Promoter in Adipose Precursor Cells

Exposure to endocrine-disrupting chemicals such as Bisphenol-A (BPA) is associated with an increase in obesity prevalence. Diet is the primary cause of human exposure to this contaminant. BPA promotes obesity by inducing adipocyte dysfunction and altering adipogenesis. Contradictory evidence and unanswered questions are reported in the literature concerning the BPA effects on adipogenesis. To clarify this issue, we tested the effects of prolonged low-dose BPA exposure on different phases of adipogenesis in committed 3T3L1 and uncommitted NIH3T3 preadipocytes. Our findings show that BPA effects on the adipogenesis are mediated by epigenetic mechanisms by reducing peroxisome proliferator-activated receptor gamma (Pparγ) promoter methylation in preadipocytes. Nevertheless, in BPA-exposed 3T3L1, Pparγ expression only transiently increases as lipid accumulation at day 4 of differentiation, without altering the adipogenic potential of the precursor cells. In the absence of differentiation mix, BPA does not make the 3T3L1 an in vitro model of spontaneous adipogenesis and the effects on the Pparγ expression are still limited at day 4 of differentiation. Furthermore, BPA exposure does not commit the NIH3T3 to the adipocyte lineage, although Pparγ overexpression is more evident both in preadipocytes and during the adipocyte differentiation. Interestingly, termination of the BPA exposure restores the Pparγ promoter methylation and inflammatory profile of the 3T3L1 cells. This study shows that BPA induces epigenetic changes in a key adipogenic gene. These modifications are reversible and do not affect preadipocyte commitment and/or differentiation. We identify an alternative transcriptional mechanism by which BPA affects gene expression and demonstrate how the challenge of preventing exposure is fundamental for human health.

Effect of prenatal bisphenol A exposure on early childhood body mass index through epigenetic influence on the insulin-like growth factor 2 receptor (IGF2R) gene

OBJECTIVES

Epigenetic mechanisms have been suggested to play a role in the link between in utero exposure to bisphenol A (BPA) and pediatric obesity; however, there is little evidence regarding this mechanism in humans. We obtained data on obesity-associated CpG sites from a previous epigenome-wide association study, and then examined whether methylation at those CpG sites was influenced by prenatal BPA exposure. We then evaluated the relationship between CpG methylation status and body mass index (BMI) in a prospective children's cohort at ages 2, 4, 6, and 8 years.

METHODS

Methylation profiles of 59 children were longitudinally analyzed at ages 2 and 6 years using the Infinium Human Methylation BeadChip. A total of 594 CpG sites known to be BMI or obesity-associated sites were tested for an association with prenatal BPA levels, categorized into low and high exposure groups based on the 80th percentile of maternal BPA levels (2.68 μg/g creatinine), followed by an analysis of the association between DNA methylation and BMI from ages 2-8.

RESULTS

There was a significant increase in the methylation levels of cg19196862 (IGF2R) in the high BPA group at age 2 years (p = 0.00030, false discovery rate corrected p < 0.10) but not at age 6. With one standard deviation increase of methylation at cg19196862 (IGF2R) at age 2 years, the linear mixed model analysis revealed that BMI during ages 2-8 years significantly increased by 0.49 (95% confidence interval; 0.08, 0.90) in girls, but not in boys. The indirect effect of prenatal BPA exposure on early childhood BMI through methylation at cg19196862 (IGF2R) at age 2 years was marginally significant.

CONCLUSIONS

Prenatal exposure to BPA may influence differential methylation of IGF2R at age 2. This result indicates that a possible sensitive period of DNA methylation occurs earlier during development, which may affect BMI until later childhood in a sex-specific manner.

Developmental programming: Transcriptional regulation of visceral and subcutaneous adipose by prenatal bisphenol-A in female sheep

BACKGROUND

Bisphenol-A (BPA) exposure is widespread and early life exposure is associated with metabolic syndrome. While visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) are implicated in the development of metabolic syndrome, the adipose depot-specific effects of prenatal BPA treatment are poorly understood.

OBJECTIVE

To determine the impact of prenatal BPA exposure on genome-wide gene expression of VAT and SAT depots.

METHODS

RNA sequencing was performed on SAT and VAT from 21-month old control and prenatal BPA-treated female sheep. Gene expression and pathway differences between SAT and VAT depots with or without prenatal BPA-treatment and the effect of prenatal BPA treatment on each depot were tested.

RESULTS

There were 179 differentially expressed genes (padjusted < 0.05, log2-fold change >2.5) between SAT and VAT. Development and immune response pathways were upregulated in SAT, while metabolic pathways were upregulated in VAT. These adipose depot-specific genes and pathways were consistent with prenatal BPA-treatment. In SAT, BPA-treatment resulted in differential expression of 108 genes (78% upregulated with BPA) and altered pathways (immune response downregulated, RNA processing upregulated). In contrast in VAT, BPA-treatment differentially expressed 4 genes and upregulated chromatin and RNA processing pathways.

CONCLUSION

Prenatal BPA-treatment induces adult depot-specific alterations in RNA expression in inflammation, RNA processing, and chromatin pathways, reflecting the diverse roles of SAT and VAT in regulating lipid storage and insulin sensitivity. These adipose tissue transcriptional dysregulations may contribute to the metabolic disorders observed in prenatal BPA-treated female sheep.

Potential Mechanisms of Bisphenol A (BPA) Contributing to Human Disease

Bisphenol A (BPA) is an organic synthetic compound serving as a monomer to produce polycarbonate plastic, widely used in the packaging for food and drinks, medical devices, thermal paper, and dental materials. BPA can contaminate food, beverage, air, and soil. It accumulates in several human tissues and organs and is potentially harmful to human health through different molecular mechanisms. Due to its hormone-like properties, BPA may bind to estrogen receptors, thereby affecting both body weight and tumorigenesis. BPA may also affect metabolism and cancer progression, by interacting with GPR30, and may impair male reproductive function, by binding to androgen receptors. Several transcription factors, including PPARγ, C/EBP, Nrf2, HOX, and HAND2, are involved in BPA action on fat and liver homeostasis, the cardiovascular system, and cancer. Finally, epigenetic changes, such as DNA methylation, histones modification, and changes in microRNAs expression contribute to BPA pathological effects. This review aims to provide an extensive and comprehensive analysis of the most recent evidence about the potential mechanisms by which BPA affects human health.

Effects of endocrine disrupting chemicals in pigs

Endocrine-disrupting chemicals (EDCs) are compounds that interfere with the expression, synthesis, and activity of hormones in organisms. They are released into the environment from flame retardants and products containing plasticizers. Persistent pesticides, such as dichlorodiphenyltrichloroethane (DDT) and hexachlorobenzene, also disrupt the endocrine system through interaction with hormone receptors. Endogenous hormones, such as 17β-estradiol (E2), are released in the urine and feces of farm animals and seep into terrestrial and aquatic ecosystems through sewage. Pigs are widely used as animal models to determine the effects of EDCs because they are physiologically, biochemically, and histologically similar to humans. EDCs primarily disrupt the reproductive and nervous systems of pigs. Moreover, embryonic development during the prenatal and early postnatal periods is particularly sensitive to EDCs. Mycotoxins, such as zearalenone, are food contaminants that alter hormonal activities in pigs. Mycotoxins also alter the innate immune system in pigs, making them vulnerable to diseases. It has been reported that farm animals are exposed to various types of EDCs, which accumulate in tissues, such as those of gonads, livers, and intestines. There is a lack of an integrated understanding of the impact of EDCs on porcine reproduction and development. Thus, this article aims to provide a comprehensive review of literature regarding the effects of EDCs in pigs.

New directions in understanding the role of environmental contaminants in child development: Four themes

Environmental contaminants, which include several heavy metals, persistent organic pollutants, and other harmful chemicals, impair several domains of child development. This article describes four themes from recent research on the impact of environmental contaminants on child development. The first theme, disparities in exposure, focuses on how marginalized communities are disproportionately exposed to harmful environmental contaminants. The second theme, complexity of exposures, encapsulates recent emphases on timing of exposures and mixtures of multiple exposures. The third theme, mechanisms that link exposures to outcomes, focuses on processes that elucidate how contaminants impact outcomes. The fourth theme, mitigating risks associated with exposures, sheds light on potential protective factors that could ameliorate many of the harmful effects of contaminant exposures. Developmental scientists are well positioned to contribute to interdisciplinary research that addresses these themes, which could foster additional conceptual and empirical innovations and inform policies and practices to mitigate risks and improve children's well-being.

Historical exposure to non-persistent environmental pollutants and risk of type 2 diabetes in a Spanish sub-cohort from the European Prospective Investigation into Cancer and Nutrition study

BACKGROUND

Environmental factors are believed to account for a substantial burden of type 2 diabetes mellitus (T2DM). Non-persistent environmental pollutants (npEPs) are a group of widely-used chemicals identified as endocrine/metabolic disrupting chemicals and obesogens. The aim of this study was to analyse the potential associations of serum levels of three groups of npEPs with the risk of incident T2DM.

METHODS

This is a longitudinal study within a sub-sample of Granada EPIC-Spain cohort (n = 670). We quantified serum concentrations of 7 npEPs: four parabens (Methylparaben (MP) ethylparaben (EP), propylparaben (PP) and butilparaben (BP); two benzophenones: Benzophenone 1 (BP1), Benzophenone 3 (BP3); and Bisphenol A (BPA). Exposure was assessed by means of chemical analyses of serum samples collected at recruitment, and information on potential confounders was gathered by using validated questionnaires at baseline. Follow-up was performed by review of patients' clinical records. Cox Proportional Hazards Models were used for the statistical analyses.

RESULTS

Median follow-up time was 23 years. There were 182 (27%) incident T2DM diagnoses in our sub-cohort. MP was the most frequently detected npEP, 88.42% samples above the limit of detection, and BP showed the lowest percentage of detection (19.21%). Those individuals within the fourth PP quartile (0.53-9.24 ng/ml) showed a statistically significant increased risk of T2DM (HR = 1.668 p = 0.012), while BP1 concentrations showed an inverse non-significant trend with the risk.

CONCLUSIONS

We evidenced a potential contribution of npEP exposure on T2DM, but no clear trend was observed. However, limitations in relation to exposure estimation might influence our findings and further research is warranted to confirm our results.

Changes in lipid profiles induced by bisphenol A (BPA) in zebrafish eleutheroembryos during the yolk sac absorption stage

Bisphenol A (BPA; 4,4'-(propane-2,2-diyl)diphenol) has been shown to act as an obesogen and to disrupt lipid metabolism in zebrafish eleutheroembryos (ZE). To characterize the consequences of this disruption, we performed a detailed lipidomic study using ZE exposed to different BPA concentrations (0, 4, 6 and 8 mg/L of BPA) from day 2 to up to day 6 post fertilization (dpf). Total lipids at 4, 5 and 6 dpf were extracted by Folch method and analyzed by high-performance thin layer chromatography (HPTLC) as wide-range preliminary screening. Selected conditions (0 and 6 mg/L of BPA) were used to obtain a high-quality lipid profile using ultra high-performance liquid chromatography/time-of-flight mass spectrometry (UHPLC-TOFMS). BPA exposed ZE exhibited increased amounts of triglycerides (TG), diglycerides (DG), phosphatidylcholines (PC) and phosphatidylinositols (PI), regarding the control group. Analysis of time- and BPA exposure-related patterns of specific lipid species showed a clear influence of unsaturation degree (mostly in DG and PC) and/or fatty acid chain length (mostly in TG and PC derivatives) on their response to the presence of BPA. A decreased yolk-sac and energy consumption in exposed individuals appeared as the main reason for the observed BPA-driven effects. Integration of these results with previous morphological, biochemical, transcriptomic, metabolomic and behavioral data suggests a disruption of different signalling pathways by BPA that starts at very low BPA concentrations, whose effects propagate across different organization levels, and that cannot be only explained by the relatively weak estrogenic effect of BPA.

Metabolomic-based assessment reveals dysregulation of lipid profiles in human liver cells exposed to environmental obesogens

Significant attention has been given to the potential of environmental chemicals to disrupt lipid homeostasis at the cellular level. These chemicals, classified as obesogens, are abundantly used in a wide variety of consumer products. However, there is a significant lack of information regarding the mechanisms by which environmental exposure can contribute to the onset of obesity and non-alcoholic fatty liver disease (NAFLD). Several studies have described the interaction of potential obesogens with lipid-related peroxisome proliferator-activated receptors (PPAR). However, no studies have quantified the degree of modification to lipidomic profiles in relevant human models, making it difficult to directly link PPAR agonists to the onset of lipid-related diseases. A quantitative metabolomic approach was used to examine the dysregulation of lipid metabolism in human liver cells upon exposure to potential obesogenic compounds. The chemicals rosiglitazone, perfluorooctanoic acid, di-2-ethylexylphthalate, and tributyltin significantly increased total lipids in liver cells, being diglycerides, triglycerides and phosphatidylcholines the most prominent. Contrarily, perfluorooctane sulfonic acid and the pharmaceutical fenofibrate appeared to lower total lipid concentrations, especially those belonging to the acylcarnitine, ceramide, triglyceride, and phosphatidylcholine groups. Fluorescence microscopy analysis for cellular neutral lipids revealed significant lipid bioaccumulation upon exposure to obesogens at environmentally relevant concentrations. This integrated omics analysis provides unique mechanistic insight into the potential of these environmental pollutants to promote diseases like obesity and NAFLD. Furthermore, this study provides a significant contribution to advance the understanding of molecular signatures related to obesogenic chemicals and to the development of alternatives to in vivo experimentation.

Development of AOP relevant to microplastics based on toxicity mechanisms of chemical additives using ToxCast™ and deep learning models combined approach

Various additives are used in plastic products to improve the properties and the durability of the plastics. Their possible elution from the plastics when plastics are fragmented into micro- and nano-size in the environment is suspected to one of the major contributors to environmental and human toxicity of microplastics. In this context, to better understand the hazardous effect of microplastics, the toxicity of chemical additives was investigated. Fifty most common chemicals presented in plastics were selected as target additives. Their toxicity was systematically identified using apical and molecular toxicity databases, such as ChemIDplus and ToxCast™. Among the vast ToxCast assays, those having intended gene targets were selected for identification of the mechanism of toxicity of plastic additives. Deep learning artificial neural network models were further developed based on the ToxCast assays for the chemicals not tested in the ToxCast program. Using both the ToxCast database and deep learning models, active chemicals on each ToxCast assays were identified. Through correlation analysis between molecular targets from ToxCast and mammalian toxicity results from ChemIDplus, we identified the fifteen most relevant mechanisms of toxicity for the understanding mechanism of toxicity of plastic additives. They are neurotoxicity, inflammation, lipid metabolism, and cancer pathways. Based on these, along with, previously conducted systemic review on the mechanism of toxicity of microplastics, here we have proposed potential adverse outcome pathways (AOPs) relevant to microplastics pollution. This study also suggests in vivo and in vitro toxicity database and deep learning model combined approach is appropriate to provide insight into the toxicity mechanism of the broad range of environmental chemicals, such as plastic additives.

Adipogenesis Regulation and Endocrine Disruptors: Emerging Insights in Obesity

Endocrine disruptors (EDs) are defined as environmental pollutants capable of interfering with the functioning of the hormonal system. They are environmentally distributed as synthetic fertilizers, electronic waste, and several food additives that are part of the food chain. They can be considered as obesogenic compounds since they have the capacity to influence cellular events related to adipose tissue, altering lipid metabolism and adipogenesis processes. This review will present the latest scientific evidence of different EDs such as persistent organic pollutants (POPs), heavy metals, "nonpersistent" phenolic compounds, triclosan, polybrominated diphenyl ethers (PBDEs), and smoke-derived compounds (benzo -alpha-pyrene) and their influence on the differentiation processes towards adipocytes in both in vitro and in vivo models.

Dichotomy of bisphenol A-induced expression of peroxisome proliferator-activated receptors in hepatic and testicular tissues in mice

Environmental and dietary exposure to bisphenol A (BPA) and its toxicological consequences are extensively reported. BPA has multiple cellular targets. One of the mechanisms of action of BPA involves interaction with and activation of nuclear receptors (NRs) including peroxisome proliferator activated-receptors (PPARs). PPARs regulate genes involved in adipogenesis, and metabolism of glucose, lipid and cholesterol. Study of tissue and dose specific PPAR expression may decipher the toxicity outcome of BPA exposure. We studied expression of three forms of PPARs in mouse liver and testes exposed to BPA for 14 days. mRNA and protein expression of all forms of PPAR increased linearly (monotonic) with the dose in the liver while non-monotonic but dose specific effects were observed in the testes showing a differential pattern of expression. However, histopathological study showed a dose-dependent pattern of changes in liver as well as testes demonstrating a monotonic effect. These findings imply that other PPAR-independent mechanisms may play a role in BPA-induced pathological changes. The present study warrants exploration of the role of PPARs in BPA-induced effects on male reproductive functions and offers an insight into the peculiar response of BPA at low subchronic levels which may be helpful in designing appropriate risk assessment framework.

Glucocorticoid and mineralocorticoid receptors and corticosteroid homeostasis are potential targets for endocrine-disrupting chemicals

Endocrine-disrupting chemicals (EDCs) have received significant concern, since they ubiquitously exist in the environment and are able to induce adverse health effects on human and wildlife. Increasing evidence shows that the glucocorticoid receptor (GR) and the mineralocorticoid receptor (MR), members of the steroid receptor subfamily, are potential targets for EDCs. GR and MR mediate the actions of glucocorticoids and mineralocorticoids, respectively, which are two main classes of corticosteroids involved in many physiological processes. The effects of EDCs on the homeostasis of these two classes of corticosteroids have also gained more attention recently. This review summarized the effects of environmental GR/MR ligands on receptor activity, and disruption of corticosteroid homeostasis. More than 130 chemicals classified into 7 main categories were reviewed, including metals, metalloids, pesticides, bisphenol analogues, flame retardants, other industrial chemicals and pharmaceuticals. The mechanisms by which EDCs interfere with GR/MR activity are primarily involved in ligand-receptor binding, nuclear translocation of the receptor complex, DNA-receptor binding, and changes in the expression of endogenous GR/MR genes. Besides directly interfering with receptors, enzyme-catalyzed synthesis and prereceptor regulation pathways of corticosteroids are also important targets for EDCs. The collected evidence suggests that corticosteroids and their receptors should be considered as potential targets for safety assessment of EDCs. The recognition of relevant xenobiotics and their underlying mechanisms of action is still a challenge in this emerging field of research.

Environmental neglect: endocrine disruptors as underappreciated but potentially modifiable diabetes risk factors

Type 2 diabetes prevalence is increasing dramatically across the globe, imposing a tremendous toll on individuals and healthcare systems. Reversing these trends requires comprehensive approaches to address both classical and emerging diabetes risk factors. Recently, environmental toxicants acting as endocrine-disrupting chemicals (EDCs) have emerged as novel metabolic disease risk factors. EDCs implicated in diabetes pathogenesis include various inorganic and organic molecules of both natural and synthetic origin, including arsenic, bisphenol A, phthalates, polychlorinated biphenyls and organochlorine pesticides. Indeed, evidence implicates EDC exposures across the lifespan in metabolic dysfunction; moreover, specific developmental windows exhibit enhanced sensitivity to EDC-induced metabolic disruption, with potential impacts across generations. Importantly, differential exposures to diabetogenic EDCs likely also contribute to racial/ethnic and economic disparities. Despite these emerging links, clinical practice guidelines fail to address this underappreciated diabetes risk factor. Comprehensive approaches to stem the tide of diabetes must include efforts to address its environmental drivers.

The Association between Bisphenol A Exposure and Obesity in Children-A Systematic Review with Meta-Analysis

Bisphenol A (BPA) is an environmental chemical that has adverse effects on health, probably causing childhood obesity. However, this association remains controversial, and it is difficult to find evidence for direct causality between environmental exposure and disease using epidemiological studies. In this study, we sought to elucidate the possible causality between BPA exposure and childhood obesity by conducting two meta-analyses showing bidirectional associations, including exposure effect by obesity and obesity risk by exposure. Articles published up to September 2017 were searched in PubMed, Embase, and Cochrane Library. We evaluated observational studies that included measurements of urinary BPA concentration and BMI or body weight. Of 436 articles, a total of 13 studies were included in the meta-analysis. Two meta-analyses were performed to investigate the association between BPA exposure and childhood obesity. The results showed that the relatively high-exposed group had a significantly higher risk of childhood obesity than the relatively low-exposed group (odds ratio = 1.566, 95% confidence interval [CI]: 1.097 to 2.234, p = 0.014). However, the obese group showed no significant difference in the BPA concentration when compared to the normal group (standardized mean difference = 0.166, 95% CI: −0.121 to 0.453, p = 0.257). This study suggested possible causality between BPA exposure and childhood obesity using data from epidemiological studies and showed that BPA exposure itself increased the risk of obesity in children.

Bisphenol a: A narrative review of prenatal exposure effects on adipogenesis and childhood obesity via peroxisome proliferator-activated receptor gamma

There is significant evidence of globally ubiquitous prenatal exposures to bisphenol A (BPA). Childhood obesity as an epidemic has been a global concern for over a decade. Experimental models and epidemiological evidence suggest that BPA may act as an obesogen during adipogenesis. Results from stem cell models and birth cohort studies support the developmental origins of health and disease theory. While literature reviews have presented a variety of potential mechanisms of BPA action during adipogenesis, there remains no consensus. This review is the first to explore the proliferator-activated receptor gamma (PPARγ) mechanism in detail. This review will also examine the obesogenic effect of prenatal exposure to BPA during critical windows of vulnerability. Although vast experimental literature exists, there is limited epidemiological evidence to support the hypothesis for the obesogenic effect of BPA. The primary goal of this review is to provide researchers with a roadmap of existing research and suggestions for future directions for analyzing the relationship between prenatal BPA exposures and childhood obesity.

Bisphenol A and adiposity measures in peripubertal boys from the INMA-Granada cohort

INTRODUCTION

Childhood obesity is one of the most serious public health challenges of our times. Although an important body of experimental evidence highlights the obesogenic potential of endocrine disruptors such as bisphenol A (BPA), the epidemiological evidence remains inconclusive and limited.

OBJECTIVE

To assess associations between urinary BPA concentrations and several adiposity measures in peripubertal boys from the Environment and Childhood (INMA) cohort in Granada, Spain.

MATERIAL AND METHODS

BPA concentrations were determined in spot urine samples from 298 boys aged 9-11, and their weight, height, waist circumference, and percentage body fat mass were measured. Overweight/obesity was defined as BMI z-score ≥85th percentile and abdominal obesity as waist-to-height ratio (WHtR) ≥0.5. Associations were assessed using multivariable linear and logistic regression models.

RESULTS

In adjusted models, each natural log-unit increase in urinary BPA concentrations was associated with higher BMI z-score (β = 0.22; 95%CI = 0.03, 0.41) and increased odds of overweight/obesity (OR = 1.46; 95%CI = 1.05, 2.05). Children with higher BPA concentrations had higher WHtR values (β = 0.007; 95%CI = -0.001, 0.015), and BPA was associated with a greater risk of abdominal obesity (OR = 1.45; 95%CI = 1.03, 2.06). No associations were found with % body fat mass.

CONCLUSIONS

BPA may exert an obesogenic effect in peripubertal boys, potentially increasing the risk of overweight/obesity, especially abdominal obesity. However, these results should be interpreted with caution given the modest sample size and the possibilities of reverse causality and residual confounding by diet and lifestyle patterns.

Prenatal Bisphenol A Exposure in Mice Induces Multitissue Multiomics Disruptions Linking to Cardiometabolic Disorders

The health impacts of endocrine-disrupting chemicals (EDCs) remain debated, and their tissue and molecular targets are poorly understood. In this study, we leveraged systems biology approaches to assess the target tissues, molecular pathways, and gene regulatory networks associated with prenatal exposure to the model EDC bisphenol A (BPA). Prenatal BPA exposure at 5 mg/kg/d, a dose below most reported no-observed-adverse-effect levels, led to tens to thousands of transcriptomic and methylomic alterations in the adipose, hypothalamus, and liver tissues in male offspring in mice, with cross-tissue perturbations in lipid metabolism as well as tissue-specific alterations in histone subunits, glucose metabolism, and extracellular matrix. Network modeling prioritized main molecular targets of BPA, including Pparg, Hnf4a, Esr1, Srebf1, and Fasn as well as numerous less studied targets such as Cyp51 and long noncoding RNAs across tissues, Fa2h in hypothalamus, and Nfya in adipose tissue. Lastly, integrative analyses identified the association of BPA molecular signatures with cardiometabolic phenotypes in mouse and human. Our multitissue, multiomics investigation provides strong evidence that BPA perturbs diverse molecular networks in central and peripheral tissues and offers insights into the molecular targets that link BPA to human cardiometabolic disorders.

Endocrine Disrupting Chemicals: An Occult Mediator of Metabolic Disease

Endocrine disrupting chemicals (EDCs), a heterogeneous group of exogenous chemicals that can interfere with any aspect of endogenous hormones, represent an emerging global threat for human metabolism. There is now considerable evidence that the observed upsurge of metabolic disease cannot be fully attributed to increased caloric intake, physical inactivity, sleep deficit, and ageing. Among environmental factors implicated in the global deterioration of metabolic health, EDCs have drawn the biggest attention of scientific community, and not unjustifiably. EDCs unleash a coordinated attack toward multiple components of human metabolism, including crucial, metabolically-active organs such as hypothalamus, adipose tissue, pancreatic beta cells, skeletal muscle, and liver. Specifically, EDCs' impact during critical developmental windows can promote the disruption of individual or multiple systems involved in metabolism, via inducing epigenetic changes that can permanently alter the epigenome in the germline, enabling changes to be transmitted to the subsequent generations. The clear effect of this multifaceted attack is the manifestation of metabolic disease, clinically expressed as obesity, metabolic syndrome, diabetes mellitus, and non-alcoholic fatty liver disease. Although limitations of EDCs research do exist, there is no doubt that EDCs constitute a crucial parameter of the global deterioration of metabolic health we currently encounter.

Effects of bisphenol A on metabolism and evidences of a mode of action mediated through endocrine disruption

Based on rodent studies after prenatal and/or perinatal or adult exposure, there is now evidence that BPA may increase metabolic disturbances eventually leading to type-2 diabetes development via an ED MoA. In particular, BPA has been shown to alter insulin synthesis and/or release by pancreatic β-cells, and insulin signaling within insulin-sensitive organs (i.e., liver, muscle, adipose tissues). This resulted in variations in the expression of specific hepatic or adipose tissue markers, which are indicative of a state of insulin resistance. These effects are considered by experts to be hallmarks of adverse hormonal effects, each leading to insulin resistance within the different insulin-sensitive tissues. Although epidemiological studies are inconclusive, these effects are considered relevant for humans, because similarities exist in homeostatic regulation of insulin production and sensitivity between rodents and humans and because evidence was also shown through in vitro experimental data using human cells or tissues.

Bisphenol A and microglia: could microglia be responsive to this environmental contaminant during neural development?

There is a growing interest in the functional role of microglia in the developing brain. In our laboratory, we have become particularly intrigued as to whether fetal microglia in the embryonic brain are susceptible to maternal challenges in utero (e.g., maternal infection, stress) and, if so, whether their precocious activation could then adversely influence brain development. One such challenge that is newly arising in this field is whether microglia might be downstream targets to endocrine-disrupting chemicals, such as the plasticizer bisphenol A (BPA), which functions in part by mimicking estrogen structure and function. A growing body of evidence demonstrates that gestational exposure to BPA has adverse effects on brain development, although the exact mechanisms are still emerging. Given that microglia express estrogen receptors and steroid-producing enzymes, microglia might be an unappreciated target of BPA. Mechanistically, we propose that BPA binding to estrogen receptors within microglia initiates transcription of downstream target genes, which then leads to activation of microglia that can then perhaps adversely influence brain development. Here, we first briefly outline the current understanding of how microglia may influence brain development and then describe how this literature overlaps with our understanding of BPA's effects during similar time points. We also outline the current literature demonstrating that BPA exposure affects microglia. We conclude by discussing our thoughts on the mechanisms through which exposure to BPA could disrupt normal microglia functions, ultimately affecting brain development that could potentially lead to lasting behavioral effects and perhaps even neuroendocrine diseases such as obesity.

Sex differences, endogenous sex-hormone hormones, sex-hormone binding globulin, and exogenous disruptors in diabetes and related metabolic outcomes

In assessing clinical and pathophysiological development of type 2 diabetes (T2D), the critical role of the sex steroids axis is underappreciated, particularly concerning the sex-specific relationships with many relevant cardiometabolic outcomes. In this issue of the Journal of Diabetes, we provide a comprehensive overview of these significant associations of germline variants in the genes governing the sex steroid pathways, plasma levels of steroid hormones, and sex hormone-binding globulin (SHBG) with T2D risk that have been observed in many clinical and high-quality large prospective cohorts of men and women across ethnic populations. Together, this body of evidence indicates that sex steroids and SHBG should be routinely incorporated into clinical characterization of T2D patients, particularly in screening prediabetic patients, such as those with metabolic syndrome, using plasma levels of SHBG. Given that several germline mutations in the SHBG gene have also been directly related to both plasma concentrations of SHBG and clinical manifestation of T2D, targeting signals in the sex steroid axis, particularly SHBG, may have significant utility in the prediction and treatment of T2D. Further, many of the environmental endocrine disrupting chemicals may exert their potential adverse effects on cardiometabolic outcomes via either estrogenic or androgenic signaling pathways, highlighting the importance of using the sex steroids and SHBG as important biochemical markers in both clinical and population studies in studying sex-specific mechanisms in the pathogenesis of T2D and its complications, as well as the need to equitably allocate resources in studying both men and women.

A plurality of molecular targets: The receptor ecosystem for bisphenol-A (BPA)

Bisphenol-A (BPA) is a well-known endocrine disrupting compound (EDC), capable of affecting the normal function and development of the reproductive system, brain, adipose tissue, and more. In spite of these diverse and well characterized effects, there is often comparatively little known about the molecular mechanisms which bring them about. BPA has traditionally been regarded as a primarily estrogenic EDC, and this perspective is often what guides research into the effects of BPA. However, emerging data from in-vitro and in-silico models show that BPA binds with a significant number of hormone receptors, including a number of nuclear and membrane-bound estrogen receptors, androgen receptors, as well as the thyroid hormone receptor, glucocorticoid receptor, and PPARγ. With this increased diversity of receptor targets, it may be possible to explain some of the more puzzling aspects of BPA pharmacology, including its non-monotonic dose-response curve, as well as experimental results which disagree with estrogenic positive controls. This paper reviews the receptors for which BPA has a known interaction, and discusses the implications of taking these receptors into account when studying the disruptive effects of BPA on growth and development.