Bisphenol A and its structural analogues exhibit differential potential to induce mitochondrial dysfunction and apoptosis in human granulosa cells.

Bisphenol A (BPA) is an endocrine disruptor strongly associated with ovarian dysfunction. BPA is being substituted by structurally similar chemicals, such as bisphenol S (BPS), bisphenol F (BPF), and bisphenol AF (BPAF). However, the toxicity of these analogues in female reproduction remains largely unknown. This study evaluated the effects of BPA and its analogues BPS, BPF, and BPAF on the mitochondrial mass and function, oxidative stress, and their potential to induce apoptosis of human granulosa cells (KGN cells). BPA and its analogues, especially BPA and BPAF, significantly decreased mitochondrial activity and cell viability. The potential of bisphenols to reduce mitochondrial mass and function differed in the following order: BPAF > BPA > BPF > BPS. Flow cytometry revealed that exposure to bisphenols significantly increased mitochondrial ROS levels and increased mitochondrial Ca2+ levels. Thus, bisphenols exposure causes mitochondrial stress in KGN cells. At the same time, bisphenols exposure significantly induced apoptosis. These results thus emphasize the toxicity of these bisphenols to cells. Our study suggests the action mechanism of BPA and its analogues in damage caused to ovarian granulosa cells. Additionally, these novel analogues may be regrettable substitutes, and the biological effects and potential risks of BPA alternatives must be evaluated.

Bisphenol S impairs mitochondrial function by targeting Myo19/oxidative phosphorylation pathway contributing to axonal and dendritic injury.

Exposure to bisphenol S (BPS) is known to adversely affect neuronal development. As pivotal components of neuronal polarization, axons and dendrites are indispensable structures within neurons, crucial for the maintenance of nervous system function. Here, we investigated the impact of BPS exposure on axonal and dendritic development both in vivo and in vitro. Our results revealed that exposure to BPS during pregnancy and lactation led to a reduction in the complexity, density, and length of axons and dendrites in the prefrontal cortex (PFC) of offspring. Employing RNA sequencing technology to elucidate the underlying mechanisms of axonal and dendritic damage induced by BPS, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis highlighted a significant alteration in the oxidative phosphorylation (OXPHOS) pathway, essential for mitochondrial function. Subsequent experiments demonstrate BPS-induced impairment in mitochondrial function, including damaged morphology, decreased adenosine triphosphate (ATP) and superoxide dismutase (SOD) levels, and increased reactive oxygen species and malondialdehyde (MDA). These alterations coincided with the downregulated expression of OXPHOS pathway-related genes (ATP6V1B1, ATP5K, NDUFC1, NDUFC2, NDUFA3, COX6B1) and Myosin 19 (Myo19). Notably, Myo19 overexpression restored the BPS-induced mitochondrial dysfunction by alleviating the inhibition of OXPHOS pathway. Consequently, this amelioration was associated with a reduction in BPS-induced axonal and dendritic injury observed in cultured neurons of the PFC.

Reproductive and transgenerational toxicity of bisphenol S exposure in pregnant rats: Insights into hormonal imbalance and steroid biosynthesis pathway disruption.

Bisphenol S (BPS) is an alternative chemical to bisphenol A commonly used in food packaging materials. It raises concerns due to potential adverse effects on human health. However, limited evidence exists regarding reproductive toxicity from BPS exposure, and the mechanism of associated transgenerational toxicity remains unclear. In this study, pregnant SD rats were exposed to two different doses of BPS (0.05 or 20 mg/kg) from GD6 to PND21. The objective was to investigate reproductive and transmissible toxicity induced by BPS, explore endocrine effects, and uncover potential underlying mechanisms in rats. Perinatal exposure to BPS in the F0 generation significantly decreased the rate of body weight, ovarian organ coefficient, and growth and development of the F1 generation. Notably, these changes included abnormal increases in body weight and length, estrous cycle disruption, and embryonic dysplasia in F1. 4D-DIA proteomic and PRM analyses revealed that exposure to 20 mg/kg group significantly altered the expression of proteins, such as Lhcgr and Akr1c3, within the steroid biosynthetic pathway. This led to elevated levels of FSH and LH in the blood. The hypothalamic-pituitary-ovarian (HPO) axis, responsible for promoting fertility through the cyclic secretion of gonadotropins and steroid hormones, was affected. RT-qPCR and Western blot results demonstrated that the expression of GnRH in the hypothalamus was decreased, the GnRHR in the pituitary gland was decreased, and the expression of FSHß and LHß in the pituitary gland was increased. Overall, BPS exposure disrupts the HPO axis, hormone levels, and steroid biosynthesis in the ovaries, affecting offspring development and fertility. This study provides new insights into the potential effects of BPS exposure on the reproductive function of the body and its relevant mechanisms of action.

Description of Solvent-Extractable Chemicals in Thermal Receipts and Toxicological Assessment of Bisphenol S and Diphenyl Sulfone.

Research on thermal receipts has previously focused on the toxic effects of dermal exposure from the most publicized developers (e.g., bisphenol A (BPA) and bisphenol S (BPS)), while no studies have reported on the other solvent-extractable compounds therein. Diphenyl sulfone (DPS) is a sensitizer added to thermal receipts, but little is known about DPS concentrations in receipts or potential toxicity. Here, we quantified BPA, BPS, and DPS concentrations and tentatively identified the solvent-extractable compounds of thermal receipts collected from three South Dakota (USA) cities during 2016-2017. An immortalized chicken hepatic cell line, cultured as 3D spheroids, was used to screen effects of DPS, BPS, and 17ß estradiol (E2; 0.1-1000 µM) on cell viability and gene expression changes. These chemicals elicited limited cytotoxicity with LC50 values ranging from 113 to 143 µM, and induced dysregulation in genes associated with lipid and bile acid homeostasis. Taken together, this study generated novel information on solvent-extractable chemicals from thermal receipts and toxicity data for DPS.

Perinatal bisphenol S exposure exacerbates the oxidative burden and apoptosis in neonatal ovaries by suppressing the mTOR/autophagy axis.

Bisphenol S (BPS) is an emerging environmental endocrine disruptor capable of crossing the placental barrier, resulting in widespread exposure to pregnant women due to its extensive usage. However, the impact of perinatal maternal exposure to BPS on reproductive health in offspring and the underlying molecular mechanism remain underexplored. In this study, gestational ICR mice were provided with drinking water containing 3.33 mg/L BPS to mimic possible human exposure in some countries. Results demonstrated that BPS accelerated the breakdown of germ-cell cysts and the assembly of primordial follicles in neonates, leading to oocyte over-loss. Furthermore, the expression levels of folliculogenesis-related genes (Kit, Nobox, Gdf9, Sohlh2, Kitl, Bmp15, Lhx8, Figla, and Tgfb1) decreased, thus compromising oocyte quality and disrupting early folliculogenesis dynamics. BPS also disrupted other aspects of offspring reproduction, including advancing puberty onset, disrupting the estrus cycle, and impairing fertility. Further investigation found that BPS exposure inhibited the activities and expression levels of antioxidant-related enzymes in neonatal ovaries, leading to the substantial accumulation of MDA and ROS. The increased oxidative burden exacerbated the intracellular apoptotic signaling, manifested by increased expression levels of pro-apoptotic markers (Bax, Caspase 3, and Caspase 9) and decreased expression levels of anti-apoptotic marker (Bcl2). Concurrently, BPS inhibited autophagy by increasing p-mTOR/mTOR and decreasing p-ULK1/ULK1, subsequently down-regulating autophagy flux-related biomarkers (LC3b/LC3a and Beclin-1) and impeding the degradation of autophagy substrate p62. However, the imbalanced crosstalk between autophagy, apoptosis and oxidative stress homeostasis was restored after rapamycin treatment. Collectively, the findings demonstrated that BPS exposure induced reproductive disorders in offspring by perturbing the mTOR/autophagy axis, and such autophagic dysfunction exacerbated redox imbalance and promoted excessive apoptosis. These results provide novel mechanistic insights into the role of autophagy in mitigating BPS-induced intergenerational reproductive dysfunction.

Long-term Bisphenol S exposure induced gut microbiota dysbiosis, obesity, hepatic lipid accumulation, intestinal lesions and dyslipidemia in mice.

Bisphenol S (BPS) is a commonly detected chemical raw material in water, which poses significant threats to both the ecological environment and human health. Despite being recognized as a typical endocrine disruptor and a substitute for Bisphenol A, the toxicological effects of BPS remain nonnegligible. In order to comprehensively understand the health impacts of BPS, a long-term (154 days) exposure experiment was conducted on mice, during which the physiological indicators of the liver, intestine, and blood were observed. The findings revealed that exposure to BPS resulted in dysbiosis of the gut microbiota, obesity, hepatic lipid accumulation, intestinal lesions, and dyslipidemia. Furthermore, there exists a significant correlation between gut microbiota and indicators of host health. Consequently, the identification of specific gut microbiota can be considered as potential biomarkers for the evaluation of risk associated with BPS. This study will effectively address the deficiency in toxicological data pertaining to BPS. The novel BPS data obtained from this research can serve as a valuable reference for professionals in the field.

SWATH-MS reveals that bisphenol A and its analogs regulate pathways leading to disruption in insulin signaling and fatty acid metabolism.

Bisphenol A (BPA) is an endocrine-disrupting chemical (EDC), associated with obesity and insulin resistance. The FDA prohibited the use of BPA-based polycarbonate resins in infant formula packaging; thus, its analogs, viz. Bisphenol S (BPS) and Bisphenol F (BPF) were considered alternatives in epoxy resins, plastics, and food cans. As these analogs might evoke a similar response, we investigated the role of Bisphenols (BPA, BPF, and BPS), on insulin signaling in CHO-HIRc-myc-GLUT4eGFP cells at environmentally relevant concentrations of 2 nM and 200 nM. Insulin signaling demonstrated that Bisphenols reduced phosphorylation of IR and AKT2, GLUT4 translocation, and glucose uptake. This was accompanied by increased oxidative stress. Furthermore, SWATH-MS-based proteomics of 3T3-L1 cells demonstrated that Bisphenol-treated cells regulate proteins in insulin resistance, adipogenesis, and fatty acid metabolism pathways differently. All three Bisphenols induced differentially expressed proteins enriched similar pathways, although their abundance differed for each Bisphenol. This might be due to their varying toxicity level, structural differences, and estrogen-mimetic activity. This study has important implications in addressing health concerns related to EDCs. Given that the analogs of BPA are considered alternatives to BPA, the findings of this study suggest they are equally potent in altering fatty acid metabolism and inducing insulin resistance.

Developmental bisphenol S toxicity in two freshwater animal models.

Freshwater animals are exposed to anthropogenic contaminants and are biomonitors of water quality and models of the deleterious impacts of exposure. Sponges, such as Ephydatia muelleri, constantly pump water and are effective indicators of water-soluble contaminants. Zebrafish (Danio rerio), native to Southeast Asia, live in the water column and feed at the water-sediment interface and are exposed to both water-soluble and insoluble contaminants. While sponges and zebrafish diverged ∼700 million years ago, they share common genetic elements, and their response to contaminants can be predictive to a wide-range of animals. An emerging contaminant, bisphenol S, was tested to evaluate its toxicity during development. The toxicity and mechanism(s) of action of BPS is not well known. Water-borne exposures to BPS caused differing hatching rates, morphological changes, and shared gene expression changes of toxicologically-relevant genes. This study shows that BPS causes similarly adverse developmental impacts pointing to some overlapping mechanisms of action.

Bisphenol S Reduces Pig Spermatozoa Motility through Different Intracellular Pathways and Mechanisms than Its Analog Bisphenol A.

Bisphenol A (BPA: 2,3-bis (4-hydroxyphenyl) propane) is an environmental chemical widely used in the manufacturing of epoxy polymers and many thermoplastic consumer products. Serious concerns about its safety led to the development of analogs, such as BPS (4-hydroxyphenyl sulfone). Very limited studies about BPS's impact on reproduction, specifically in spermatozoa, exist in comparison with BPA. Therefore, this work aims to study the in vitro impact of BPS in pig spermatozoa in comparison with BPA, focusing on sperm motility, intracellular signaling pathways and functional sperm parameters. We have used porcine spermatozoa as an optimal and validated in vitro cell model to investigate sperm toxicity. Pig spermatozoa were exposed to 1 and 100 µM BPS or BPA for 3 and 20 h. Both bisphenol S and A (100 µM) significantly reduce pig sperm motility in a time-dependent manner, although BPS exerts a lower and slower effect than BPA. Moreover, BPS (100 µM, 20 h) causes a significant increase in the mitochondrial reactive species, whereas it does not affect sperm viability, mitochondrial membrane potential, cell reactive oxygen species, GSK3α/ß phosphorylation or phosphorylation of PKA substrates. However, BPA (100 µM, 20 h) leads to a decrease in sperm viability, mitochondrial membrane potential, GSK3ß phosphorylation and PKA phosphorylation, also causing an increase in cell reactive oxygen species and mitochondrial reactive species. These intracellular effects and signaling pathways inhibited might contribute to explaining the BPA-triggered reduction in pig sperm motility. However, the intracellular pathways and mechanisms triggered by BPS are different, and the BPS-caused reduction in motility can be only partially attributed to an increase in mitochondrial oxidant species.

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

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

Effect of Bisphenol S on testicular tissue after low-dose lactation exposure.

Exposure to endocrine disruptors such as bisphenols, can lead to and be the explanation for idiopathic infertility. In our study, we assessed the effect of exposure to bisphenol S (BPS) via breast milk on the testicular tissue health of adult male mice. Lactating dams were exposed to BPS through drinking water (0.216 ng g bw/day and 21.6 ng g bw/day) from post-natal day 0-15. Although there was no significant difference in testicular histopathology between the control and experimental groups, we observed an increase in the number of tight and gap junctions in the blood-testis barrier (BTB) of adult mice after lactation BPS exposure. Moreover, there was an increase in oxidative stress markers in adult testicular tissue of mice exposed via breast milk. Our lactation model indicates that breast milk is a route of exposure to an endocrine disruptor that can be responsible for idiopathic male infertility through the damage of the BTB and weakening of oxidative stress resistance in adulthood.

Bisphenol S induces cardiovascular toxicity by disturbing the development of the common cardinal vein and myocardial contractility in zebrafish embryos.

Bisphenol S (BPS) has been widely used as a substitute for bisphenol A in industrial manufacturing. However, the safety of BPS is controversial, and the mechanism by which BPS exerts cardiovascular toxicity remains unclear. In this study, zebrafish embryos, including wild-type zebrafish and transgenic (flk1:eGFP), (gata1:DsRed) and (cmlc2:eGFP) zebrafish at 2 h postfertilization (hpf), were exposed to BPS at concentrations of 1, 10 and 100 µg/L for 24, 48 and 72 h, respectively. The data showed that BPS accelerated the expansion of the common cardinal vein and inhibited lumen formation between 24 hpf and 72 hpf. Moreover, low-dose BPS disturbed cardiac muscle contraction by breaking the calcium balance in cardiac muscle cells according to the RNA-seq results. As a consequence, increased heart rate and irregular blood circulation were observed in the BPS treatment groups. This result suggested that BPS at environmental relevant concentrations caused cardiovascular toxicity during the development of zebrafish embryos, possibly being an important inducer of cardiovascular injury later in life. These findings provide insight into the rational and safe application of BPS.

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

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

Bisphenol A replacement chemicals, BPF and BPS, induce protumorigenic changes in human mammary gland organoid morphology and proteome.

SignificanceBisphenol A (BPA), found in many plastic products, has weak estrogenic effects that can be harmful to human health. Thus, structurally related replacements-bisphenol S (BPS) and bisphenol F (BPF)-are coming into wider use with very few data about their biological activities. Here, we compared the effects of BPA, BPS, and BPF on human mammary organoids established from normal breast tissue. BPS disrupted organoid architecture and induced supernumerary branching. At a proteomic level, the bisphenols altered the abundance of common targets and those that were unique to each compound. The latter included proteins linked to tumor-promoting processes. These data highlighted the importance of testing the human health effects of replacements that are structurally related to chemicals of concern.

Bisphenol S Impairs Invasion and Proliferation of Extravillous Trophoblasts Cells by Interfering with Epidermal Growth Factor Receptor Signaling.

The placenta supports fetal growth and is vulnerable to exogenous chemical exposures. We have previously demonstrated that exposure to the emerging chemical bisphenol S (BPS) can alter placental endocrine function. Mechanistically, we have demonstrated that BPS interferes with epidermal growth factor receptor (EGFR) signaling, reducing placenta cell fusion. Extravillous trophoblasts (EVTs), a placenta cell type that aids with vascular remodeling, require EGF to invade into the maternal endometrium. We hypothesized that BPS would impair EGF-mediated invasion and proliferation in EVTs. Using human EVTs (HTR-8/SVneo cells), we tested whether BPS could inhibit the EGF response by blocking EGFR activation. We also evaluated functional endpoints of EGFR signaling, including EGF endocytosis, cell invasion and proliferation, and endovascular differentiation. We demonstrated that BPS blocked EGF-induced phosphorylation of EGFR by acting as a competitive antagonist to EGFR. Transwell assay and a three-dimensional microfluidic chip invasion assay revealed that BPS exposure can block EGF-mediated cell invasion. BPS also blocked EGF-mediated proliferation and endovascular differentiation. In conclusion, BPS can prevent EGF-mediated EVT proliferation and invasion through EGFR antagonism. Given the role of EGFR in trophoblast proliferation and differentiation during placental development, our findings suggest that maternal exposure to BPS may contribute to placental dysfunction via EGFR-mediated mechanisms.

Regulatory and academic studies to derive reference values for human health: The case of bisphenol S.

The close structural analogy of bisphenol (BP) S with BPA, a recognized endocrine-disrupting chemical and a substance of very high concern in the European Union, highlights the need to assess the extent of similarities between the two compounds and carefully scrutinize BPS potential toxicity for human health. This analysis aimed to investigate human health toxicity data regarding BPS, to find a point of departure for the derivation of human guidance values. A systematic and transparent methodology was applied to determine whether European or international reference values have been established for BPS. In the absence of such values, the scientific literature on human health effects was evaluated by focusing on human epidemiological and animal experimental studies. The results were analyzed by target organ/system: male and female reproduction, mammary gland, neurobehavior, and metabolism/obesity. Academic experimental studies were analyzed and compared to regulatory data including subchronic studies and an extended one-generation and reproduction study. In contrast to the regulatory studies, which were performed at dose levels in the mg/kg bw/day range, the academic dataset on specific target organs or systems showed adverse effects for BPS at much lower doses (0.5-10 µg/kg bw/day). A large disparity between the lowest-observed-adverse-effect levels (LOAELs) derived from regulatory and academic studies was observed for BPS, as for BPA. Toxicokinetic data on BPS from animal and human studies were also analyzed and showed a 100-fold higher oral bioavailability compared to BPA in a pig model. The similarities and differences between the two bisphenols, in particular the higher bioavailability of BPS in its active (non-conjugated) form and its potential impact on human health, are discussed. Based on the available experimental data, and for a better human protection, we propose to derive human reference values for exposure to BPS from the N(L)OAELs determined in academic studies.

Low-dose bisphenol S exposure induces hypospermatogenesis and mitochondrial dysfunction in rats: A possible implication of StAR protein.

A wide variety of environmental chemicals/xenobiotics including bisphenol A (BPA) has been shown to cause male reproductive dysfunctions and infertility. Recently, bisphenol S (BPS) replaces BPA, in several products, including foodstuffs, under the BPA-free label. However, several studies have raised inquietude about the potential adverse effects of BPS. The present study was conducted to evaluate sperm parameters, biochemical parameters, mitochondrial function, and histopathological patterns after post-lactation BPS exposure at a low dose. Male rats (21 days old) were exposed to water containing BPS at 50 µg/L in drinking water for 10 weeks. Results showed no significant alteration in the gonadosomatic index (GSI) and relative reproductive organs weight. However, a significant reduction in epididymal sperm parameters (number, viability, and mobility) with morphological abnormalities were observed in the BPS group compared to control. An increase of malondialdehyde (MDA) level accompanied by antioxidant defense alteration particularly, in glutathione peroxidase activity, as well as a defective mitochondrial function were observed in testicular tissues of BPS treated rats. More importantly, in histopathological diagnosis, BPS treatment induces hypospermatogenesis and alteration in Sertoli cells. In silico docking studies illustrated BPS binds with steroidogenic acute regulatory (StAR) protein thereby affecting the transport of cholesterol into mitochondria resulting in decreased steroidogenesis. These results reflect a reprotoxic effect of BPS vould potentially lead to fertility reduction, in sexually maturity age. We highlighted that post-lactation exposure to BPS, equivalent in humans to the period covering childhood and adolescent stages, disrupt male reproduction function.

The effect of endocrine disrupting chemicals on the vitronectin-receptor (integrin αvß3)-mediated cell adhesion of human umbilical vein endothelial cells.

Endocrine disrupting chemicals (EDCs) are associated with cancer development and progression due to their promotion of increased cell invasiveness and metastasis formation. However, the effects of EDCs on cell adhesion mediated through integrins have not been well studied to date. Their actions are implicated by binding sites for hormones on the vitronectin receptor (VTNR; or integrin αvß3), which is involved in tumor angiogenesis and metastasis. VTNR-expressing human umbilical vein endothelial cells (HUVECs) were used to determine the effects of EDCs and endogenous hormones on cell adhesion to vitronectin-coated surfaces, and on VTNR activation. Cell adhesion was significantly increased for bisphenol A, triclocarban, and triclosan (10, 100 nM; p < 0.05), with similar trends for bisphenols AF and S (10, 100 nM; p > 0.05). No changes in cell adhesion were seen for 5α-dihydrotestosterone, 17ß-estradiol, triiodothyronine, imatinib and paroxetine. These data indicate that EDC-mediated increases in HUVEC adhesion to vitronectin are not mediated through androgenic, estrogenic, or thyroid activities, nor through activation of VTNR. Although these effects of EDCs on HUVEC adhesion require further investigation of the underlying mechanism(s) of action to define their biological relevance, the low-dose effects and nonmonotonic responses revealed here define the need for further investigation of these EDCs.

Early developmental exposure to bisphenol A and bisphenol S disrupts socio-cognitive function, isotocin equilibrium, and excitation-inhibition balance in developing zebrafish.

Dysregulation of the oxytocinergic system and excitation/inhibition (E/I) balance in synaptic transmission and neural circuits are common hallmarks of various neurodevelopmental disorders. Several experimental and epidemiological studies have shown that perinatal exposure to endocrine-disrupting chemicals bisphenol A (BPA) and bisphenol S (BPS) may contribute to a range of childhood neurodevelopmental disorders. However, the effects of BPA and BPS on social-cognitive development and the associated mechanisms remain largely unknown. In this study, we explored the impacts of early developmental exposure (2hpf-5dpf) to environmentally relevant concentrations of BPA, and its analog BPS (0.001, 0.01, and 0.1 µM), on anxiety, social behaviors, and memory performance in 21 dpf zebrafish larvae. Our results revealed that early-life exposure to low concentrations of BPA and BPS elevated anxiety-like behavior, while fish exposed to higher concentrations of these chemicals displayed social deficits and impaired object recognition memory. Additionally, we found that co-exposure with an aromatase inhibitor antagonized BPA- and BPS-induced effects on anxiety levels and social behaviors, while the co-exposure to an estrogen receptor antagonist restored recognition memory in zebrafish larvae. These results indicate that BPA and BPS may affect social-cognitive function through distinct mechanisms. On the other hand, exposure to low BPA/BPS concentrations increased both the mRNA and protein levels of isotocin (zebrafish oxytocin) in the zebrafish brain, whereas a reduction in its mRNA level was observed at higher concentrations. Further, alterations in the transcript abundance of chloride transporters, and molecular markers of gamma-aminobutyric acid (GABA) and glutamatergic systems, were observed in the zebrafish brain, suggesting possible E/I imbalance following BPA or BPS exposure. Collectively, the results of this study demonstrate that early-life exposure to low concentrations of the environmental contaminants BPA and BPS can interfere with the isotocinergic signaling pathway and disrupts the establishment of E/I balance in the developing brain, subsequently leading to the onset of a suite of behavioral deficits and neurodevelopmental disorders.

Developmental toxicity of bisphenol S in Caenorhabditis elegans and NODEF mice.

The growing concern surrounding bisphenol A (BPA) has led to increased industrial production and application of its analog bisphenol S (BPS). The goals of this study were: (1) To examine the generational effects in the nematode C. elegans for up to three generations following developmental exposure to BPS (0.1, 1.0, 5.0 and 10.0 µM), and (2) To examine the neurotoxicity and metabolic toxicity in NODEF mouse offspring exposed to BPS (3 µg/kg BW) in utero throughout gestation once/day via oral pipette. First, worms were exposed to BPS developmentally for a single period of 48 hours and then propagated for 2 additional generations. Exposure to 0.1 and 1.0 µM BPS decreased lifespan and the number of progeny with an ability to recover in subsequent generations. In contrast, worms exposed to 5.0 or 10.0 µM BPS exhibited a continuous effect in the second generation, e.g., decreased lifespan and reduced number of progeny. Only worms exposed to 10.0 µM BPS continued to have a significant long-term effect (e.g., decreased lifespan) through the third generation. In addition, worms developmentally exposed to BPS at 5.0 µM and 10.0 µM also showed decreases in body bends. In contrast, worms exposed to 0.1 µM BPS exhibited a significant increase in head thrashes. When the multigenerational effects were examined by exposing worms to BPS for 48 hours developmentally at each generation for three generations, an accumulative effect was observed in worms treated with 0.1 or 1.0 µM BPS for two generations, but not for three generations, suggesting a threshold existed. Worms exposed to either 5.0 or 10.0 µM BPS demonstrated accumulative effects through two and three generations. When the developmental effects of BPS were studied in NODEF mice, offspring exposed gestationally exhibited behavioral deficits at 12, but not at 3, weeks of age. Specifically, female offspring had decreases in working and short-term memories while male offspring showed increases in hyperactivity and anxiety-like behaviors. In summary, this study demonstrates the sex-related effects of BPS in NODEF mouse offspring exposed in utero, along with the generational effects observed in C. elegans.