Health risks of Bisphenol-A exposure: From Wnt signaling perspective

Human beings are routinely exposed to chronic and low dose of Bisphenols (BPs) due to their widely pervasiveness in the environment. BPs hold similar chemical structures to 17β-estradiol (E2) and thyroid hormone, thus posing threats to human health by rendering the endocrine system dysfunctional. Among BPs, Bisphenol-A (BPA) is the best-known and extensively studied endocrine disrupting compound (EDC). BPA possesses multisystem toxicity, including reproductive toxicity, neurotoxicity, hepatoxicity and nephrotoxicity. Particularly, the central nervous system (CNS), especially the developing one, is vulnerable to BPA exposure. This review describes our current knowledge of BPA toxicity and the related molecular mechanisms, with an emphasis on the role of Wnt signaling in the related processes. We also discuss the role of oxidative stress, endocrine signaling and epigenetics in the regulation of Wnt signaling by BPA exposure. In summary, dysfunction of Wnt signaling plays a key role in BPA toxicity and thus can be a potential target to alleviate EDCs induced damage to organisms.

Bisphenol and phthalate exposure during pregnancy and the development of childhood lung function and asthma. The generation R study

BACKGROUND

Fetal exposure to bisphenols and phthalates may lead to alterations in the respiratory and immune system development in children, and to adverse respiratory health. AIMTO STUDY: the associations of fetal bisphenols and phthalates exposure with lung function and asthma at age 13 years.

STUDY DESIGN

and Methods This study among 1020 children was embedded in a population-based prospective cohort study. We measured maternal urine bisphenol and phthalate concentrations in first, second and third trimester of pregnancy, and lung function by spirometry and asthma by questionnaires at age 13 years. Multivariable linear and logistic regression models were applied.

RESULTS

Maternal urine bisphenol and phthalate concentrations averaged during pregnancy were not associated with childhood lung function or asthma. Associations of maternal urine bisphenol and phthalate concentrations in specific trimesters with respiratory outcomes showed that one interquartile range increase in the natural log transformed maternal urine mono-isobutyl phthalate concentration in second trimester was associated with a higher FEV₁/FVC, but not with asthma, accounting for confounders and multiple-testing correction. Although there were associations of higher second trimester bisphenol S with a lower FVC and FEV₁ in boys and girls, and of higher first trimester bisphenol S with a decreased risk of asthma in boys and an increased risk of asthma in girls, these results did not remain significant after correction for multiple testing. Results were not modified by maternal history of asthma or atopy.

CONCLUSIONS

Maternal urine bisphenol and phthalate concentrations averaged or in specific trimesters during pregnancy were not strongly associated with childhood lung function and asthma at age 13 years. BPS, as a BPA substitute, tended to be associated with impaired lung function and altered risk of asthma, partly sex-dependent, but its strength was limited by a relatively low detection rate and should be queried in contemporary cohorts.

Re-evaluation of the risks to public health related to the presence of bisphenol A (BPA) in foodstuffs

In 2015, EFSA established a temporary tolerable daily intake (t-TDI) for BPA of 4 μg/kg body weight (bw) per day. In 2016, the European Commission mandated EFSA to re-evaluate the risks to public health from the presence of BPA in foodstuffs and to establish a tolerable daily intake (TDI). For this re-evaluation, a pre-established protocol was used that had undergone public consultation. The CEP Panel concluded that it is Unlikely to Very Unlikely that BPA presents a genotoxic hazard through a direct mechanism. Taking into consideration the evidence from animal data and support from human observational studies, the immune system was identified as most sensitive to BPA exposure. An effect on Th17 cells in mice was identified as the critical effect; these cells are pivotal in cellular immune mechanisms and involved in the development of inflammatory conditions, including autoimmunity and lung inflammation. A reference point (RP) of 8.2 ng/kg bw per day, expressed as human equivalent dose, was identified for the critical effect. Uncertainty analysis assessed a probability of 57-73% that the lowest estimated Benchmark Dose (BMD) for other health effects was below the RP based on Th17 cells. In view of this, the CEP Panel judged that an additional uncertainty factor (UF) of 2 was needed for establishing the TDI. Applying an overall UF of 50 to the RP, a TDI of 0.2 ng BPA/kg bw per day was established. Comparison of this TDI with the dietary exposure estimates from the 2015 EFSA opinion showed that both the mean and the 95th percentile dietary exposures in all age groups exceeded the TDI by two to three orders of magnitude. Even considering the uncertainty in the exposure assessment, the exceedance being so large, the CEP Panel concluded that there is a health concern from dietary BPA exposure.

In utero exposure to bisphenols and asthma, wheeze, and lung function in school-age children: a prospective meta-analysis of 8 European birth cohorts

BACKGROUND

In utero exposure to bisphenols, widely used in consumer products, may alter lung development and increase the risk of respiratory morbidity in the offspring. However, evidence is scarce and mostly focused on bisphenol A (BPA) only.

OBJECTIVE

To examine the associations of in utero exposure to BPA, bisphenol F (BPF), and bisphenol S (BPS) with asthma, wheeze, and lung function in school-age children, and whether these associations differ by sex.

METHODS

We included 3,007 mother-child pairs from eight European birth cohorts. Bisphenol concentrations were determined in maternal urine samples collected during pregnancy (1999-2010). Between 7 and 11 years of age, current asthma and wheeze were assessed from questionnaires and lung function by spirometry. Wheezing patterns were constructed from questionnaires from early to mid-childhood. We performed adjusted random-effects meta-analysis on individual participant data.

RESULTS

Exposure to BPA was prevalent with 90% of maternal samples containing concentrations above detection limits. BPF and BPS were found in 27% and 49% of samples. In utero exposure to BPA was associated with higher odds of current asthma (OR = 1.13, 95% CI = 1.01, 1.27) and wheeze (OR = 1.14, 95% CI = 1.01, 1.30) (p-interaction sex = 0.01) among girls, but not with wheezing patterns nor lung function neither in overall nor among boys. We observed inconsistent associations of BPF and BPS with the respiratory outcomes assessed in overall and sex-stratified analyses.

CONCLUSION

This study suggests that in utero BPA exposure may be associated with higher odds of asthma and wheeze among school-age girls.

Integration of data from the cell-based ERK1/2 ELISA and the Comparative Toxicogenomics Database deciphers the potential mode of action of bisphenol A and benzo[a]pyrene in lung neoplasm

Chemicals can activate a variety of signaling pathways, initiating changes in gene expression and cellular functions. Here, we combined experimental data on the chemical-induced extracellular signal-regulated kinase 1/2 (ERK1/2) activation with the Comparative Toxicogenomics Database (CTD) to connect signaling, genes, and phenotypes to reveal the potential chemical's mode of action (MOA) responsible for the disease state. Experimental data on ERK1/2 activation were derived from the cell-based phospho-ERK1/2 ELISA on human alveolar epithelial cells A549. A549 cells were exposed to bisphenol A (BPA), benzo[a]pyrene (BaP), tributyltin (TBT), and ibuprofen from 10^-12 M to 10^-5 M. Results show that BPA, BaP, and TBT can activate ERK1/2 in A549 cells. We selected BPA and BaP to elucidate the molecular events connecting chemical exposure, ERK1/2 signaling, phenotypes, and lung neoplasm (LN) using CTD. CTD analysis showed that BPA and BaP share 26 mitogen-activated protein kinase 1/3 (MAPK1/3) signaling genes associated with LN. Phenotype prioritization revealed 37 BPA, 10 BaP, and 11 shared key phenotypes associated with LN. Alignment of MAPK1/3 signaling genes and phenotypes showed that ERK1/2 and oxidative stress, EGFR gene, and positive regulation of cell proliferation and migration could be the shared key events (KE) for BPA and BaP. This analysis also identified protein kinase B and ERK1/2 signaling, FGF9, FGFR1 and FGFR2 genes, positive regulation of cell proliferation and angiogenesis as KE in MOA for BPA, whereas ERK1/2 signaling, IL6 and DAB2IP genes, negative regulation of cell proliferation and inflammatory response were identified as KE in MOA for BaP.

Bisphenol A increases TLR4-mediated inflammatory response by up-regulation of autophagy-related protein in lung of adolescent mice

In previous studies we found that bisphenol A (BPA) aggravated OVA-induced lung inflammation. The aim of this research was to determine whether BPA exposure alone also induced inflammatory response in the lungs, which mechanism was associated with TLR4/NF-κB signaling pathway and the activation of mTOR-mediated autophagy. Female C57BL/6 mice aged 4 weeks were randomly divided into three groups (10/group): control group, 0.1 and 0.2 μg mL^-1 BPA groups. BPA induced the pathological changes in the lung and increased the levels of cytokines and inflammatory cells, as well as affected autophagy related proteins expression. In addition, the RAW264.7 cell culture experiment was conducted in order to confirm the role of autophagy. We found that BPA can enhance autophagy flux by enhancing autophagosome formation. It was further confirmed the details of the mechanism of action with chloroquine (CQ, a compound that inhibits the fusion of autophagosomes and lysosomes) intervention. The inhibition of autophagy led to down-regulation of expression levels associated with inflammation. This research results indicated that BPA induced inflammatory response in vitro and in vivo, and its mechanism may be related to TLR4/NF-κB signaling pathway and the activation of mTOR-mediated autophagy. After autophagy was suppressed, the inflammatory response also weakened. Our findings provide a new perspective into the mechanisms underlying inflammatory responses induced by the environmental exposure. These findings indicate that therapeutic strategies targeting autophagy may provide a new method for the treatment of inflammatory diseases.

Effects on the liver lipidome of rat offspring prenatally exposed to bisphenol A

Bisphenol A (BPA) is a well-known endocrine disruptor that has obesogenic properties. We have previously reported sex- and age-dependent changes in hepatic transcriptome and proteome of several lipid homeostasis-related genes in rat offspring prenatally exposed to BPA. To further understand the impacts of prenatal BPA exposure, we analyzed lipidomic profiles in the postnatal day (PND) 21 and 60 rats using a high-resolution QTOF mass spectrometer coupled with a HPLC system. We found that the total lipid content was significantly decreased in PND21 females prenatally exposed to 5000 μg/kg bw/day of BPA. Levels of total fatty acids, acylcarnitines, and monoacylglycerols significantly increased in both female and male BPA-exposed rats at PND21. An elevation in total cholesterol esters and reductions in triacylglycerols and monogalactosyl diacylglycerols were found only in PND21 females prenatally exposed to BPA. Interestingly, opposite responses were observed for phospholipids and sphingolipids between PND21 females and males following BPA exposure. The effects on the body weight and total lipid content were mitigated in the latter stage, although the alterations of lipid profiles continued until PND60. A Data Integration Analysis for Biomarker discovery using Latent cOmponents (DIABLO) revealed a high correlation of the lipidome with our previously published transcriptome data. DIABLO also identified potential biomarkers of prenatal exposure to BPA; glycerol-3-phosphate dehydrogenase 1 (Gpd1) and glyceronephosphate O-acyltransferase (Gnpat), which are involved in the glycerophospholipid metabolism, in females and males, respectively. Collectively, we highlighted the sex- and age-dependent effects of prenatal BPA exposure on hepatic lipid homeostasis in rat offspring.

The impacts of intrauterine Bisphenol A exposure on pregnancy and expression of miRNAs related to heart development and diseases in animal model

This study aimed to examine the impact of BPA exposure on pregnancy and foetuses on cardiac tissues and the expression of cardiac microRNAs (miRNAs) related to heart development and diseases. Pregnancy is known to be the "critical windows" in determining the offspring physical and cells development in their life after birth. The increment of the risk of cardiovascular disease (CVD) in a later stage of life has been reported by few studies demonstrated from prenatal exposure of BPA. BPA has been shown to alter miRNAs expression profiles for organ development, regeneration and metabolic functions. These alterations have been associated with the risk of CVDs. However, the associations between pregnancy outcomes and miRNAs expression in cardiac of mother- and foetuses-exposed to BPA are still not entirely explored. In BPA-exposed pregnant rat groups, a significant weight gained was observed in comparison to control (p < 0.05). Interestingly, significant changes in systolic and diastolic blood pressure between the first and third trimester of BPA-exposed pregnant rats were also observed (p < 0.05). In BPA-exposed pregnant rats, miR-499-5p was significantly altered in the heart (p < 0.01). Meanwhile, altered miR-17-5p, -208-3p, and -210-3p expressions were observed in all heart of the foetuses from BPA-exposed pregnant rats (p < 0.05). In H&E staining, BPA-exposed foetal hearts showed a sign of fibrosis while BPA-exposed pregnant rats showed muscle remnant. Masson trichrome staining further confirmed the presence of fibrosis observed in BPA-exposed foetal heart and reduced expression of cardiac troponin I (cTnI) was also observed in BPA-exposed foetal heart. In summary, altered cardiac miRNAs with histological changes were observed in both mother- and foetus-exposed BPA These findings put forward the importance of future work to further understand how prenatal BPA exposure affect foetuses in their later stage of life.

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.

Melatonin attenuates bisphenol A-induced toxicity of the adrenal gland of Wistar rats

This study investigated the role of melatonin (MLT) on adrenal gland toxicity induced by bisphenol A (BPA). Adult male rats were divided into four groups of seven animals each: Group I (control) received oral 0.2 ml canola oil; group II received intra-peritoneal 10 mg/kg BW/day MLT; and group III received oral BPA (10 mg/kg BW/day). Group IV rats were treated with same dose of BPA as group III with a concomitant intra-peritoneal 10 mg/kg BW/day MLT. All treatments lasted for 14 days. BPA significantly increased (P < 0.05) adrenal index, circulating levels of corticosterone and adrenocorticotropic hormone (ACTH) in the rats. BPA caused marked vascular congestion, hyperplasia, cellular distortion, increased lipid peroxidation, decreased antioxidant enzymes, and decreased expression of αSmooth muscle actin as well as vimentin proteins. The concomitant treatment with MLT ameliorated these BPA-induced alterations. It is likely that melatonin attenuates BPA-induced alterations of the adrenal gland of rats through the antioxidant defense mechanism.

Bisphenol A stimulates adrenal cortical cell proliferation via ERβ-mediated activation of the sonic hedgehog signalling pathway

We previously demonstrated that prenatal exposure to bisphenol A (BPA) resulted in increased adrenal gland weight independent of changes in plasma ACTH levels in adult mouse offspring. This finding suggested that BPA exposure likely had a direct effect on adrenal development. Given that (1) sonic hedgehog (Shh) signaling is essential for adrenal development; (2) deletion of the Shh gene in mice results in adrenal hypoplasia; (3) BPA is known to signal through estrogen receptor β (ERβ); and (4) ERβ is highly expressed in adrenal glands; we hypothesized that BPA stimulates adrenal cell proliferation via ERβ-mediated activation of the Shh pathway. To test this hypothesis, the human adrenal cell line, H295A cells, was used as an in vitro model system. Our main findings were: (1) BPA increased cell number and protein levels of proliferating cell nuclear antigen (PCNA; a universal marker of cell proliferation), cyclin D1 and D2 (key proliferation factors), as well as Shh and its key transcriptional regulator Gli1; (2) cyclopamine, a Shh pathway inhibitor, blocked these stimulatory effects of BPA on cell proliferation; (3) BPA increased the nuclear translocation of ERβ; and (4) the ERβ-specific agonist DPN mimicked while the ERβ-specific antagonist PHTPP abrogated the stimulatory effects of BPA on cell proliferation and Shh signaling. Taken together, these findings demonstrate that BPA stimulates adrenal cell proliferation likely through ERβ-mediated activation of the Shh signaling pathway. Thus, the present study provides novel insights into the molecular mechanisms underlying our previously reported BPA-induced aberrant adrenal phenotype.

Bisphenol A induces DSB-ATM-p53 signaling leading to cell cycle arrest, senescence, autophagy, stress response, and estrogen release in human fetal lung fibroblasts

Experimental and/or epidemiological studies suggest that prenatal exposure to bisphenol A (BPA) may delay fetal lung development and maturation and increase the susceptibility to childhood respiratory disease. However, the underlying mechanisms remain to be elucidated. In our previous study with cultured human fetal lung fibroblasts (HFLF), we demonstrated that 24-h exposure to 1 and 100 µM BPA increased GPR30 protein in the nuclear fraction. Exposure to 100 μM BPA had no effects on cell viability, but increased cytoplasmic expression of ERβ and release of GDF-15, as well as decreased release of IL-6, ET-1, and IP-10 through suppression of NFκB phosphorylation. By performing global gene expression and pathway analysis in this study, we identified molecular pathways, gene networks, and key molecules that were affected by 100, but not 0.01 and 1 µM BPA in HFLF. Using multiple genomic and proteomic tools, we confirmed these changes at both gene and protein levels. Our data suggest that 100 μM BPA increased CYP1B1 and HSD17B14 gene and protein expression and release of endogenous estradiol, which was associated with increased ROS production and DNA double-strand breaks, upregulation of genes and/or proteins in steroid synthesis and metabolism, and activation of Nrf2-regulated stress response pathways. In addition, BPA activated ATM-p53 signaling pathway, resulting in increased cell cycle arrest at G1 phase, senescence and autophagy, and decreased cell proliferation in HFLF. The results suggest that prenatal exposure to BPA at certain concentrations may affect fetal lung development and maturation, and thereby affecting susceptibility to childhood respiratory diseases.

Recent advances in our understanding of the mechanisms of late lung development and bronchopulmonary dysplasia

The objective of lung development is to generate an organ of gas exchange that provides both a thin gas diffusion barrier and a large gas diffusion surface area, which concomitantly generates a steep gas diffusion concentration gradient. As such, the lung is perfectly structured to undertake the function of gas exchange: a large number of small alveoli provide extensive surface area within the limited volume of the lung, and a delicate alveolo-capillary barrier brings circulating blood into close proximity to the inspired air. Efficient movement of inspired air and circulating blood through the conducting airways and conducting vessels, respectively, generates steep oxygen and carbon dioxide concentration gradients across the alveolo-capillary barrier, providing ideal conditions for effective diffusion of both gases during breathing. The development of the gas exchange apparatus of the lung occurs during the second phase of lung development-namely, late lung development-which includes the canalicular, saccular, and alveolar stages of lung development. It is during these stages of lung development that preterm-born infants are delivered, when the lung is not yet competent for effective gas exchange. These infants may develop bronchopulmonary dysplasia (BPD), a syndrome complicated by disturbances to the development of the alveoli and the pulmonary vasculature. It is the objective of this review to update the reader about recent developments that further our understanding of the mechanisms of lung alveolarization and vascularization and the pathogenesis of BPD and other neonatal lung diseases that feature lung hypoplasia.

Molecular targets of developmental exposure to bisphenol A in diabesity: a focus on endoderm-derived organs

Several studies associate foetal human exposure to bisphenol A (BPA) to metabolic/endocrine diseases, mainly diabesity. They describe the role of BPA in the disruption of pancreatic beta cell, adipocyte and hepatocyte functions. Indeed, the complexity of the diabesity phenotype is due to the involvement of different endoderm-derived organs, all targets of BPA. Here, we analyse this point delineating a picture of different mechanisms of BPA toxicity in endoderm-derived organs leading to diabesity. Moving from epidemiological data, we summarize the in vivo experimental data of the BPA effects on endoderm-derived organs (thyroid, pancreas, liver, gut, prostate and lung) after prenatal exposure. Mainly, we gather molecular data evidencing harmful effects at low-dose exposure, pointing to the risk to human health. Although the fragmentation of molecular data does not allow a clear conclusion to be drawn, the present work indicates that the developmental exposure to BPA represents a risk for endoderm-derived organs development as it deregulates the gene expression from the earliest developmental stages. A more systematic analysis of BPA impact on the transcriptomes of endoderm-derived organs is still missing. Here, we suggest in vitro toxicogenomics approaches as a tool for the identification of common mechanisms of BPA toxicity leading to the diabesity in organs having the same developmental origin.

Effects of prenatal bisphenol-A exposure and postnatal overfeeding on cardiovascular function in female sheep

Bisphenol-A (BPA) is a widely used endocrine-disrupting chemical. Prenatal exposure to BPA is known to affect birth weight, but its impact on the cardiovascular system has not been studied in detail. In this study, we investigated the effects of prenatal BPA treatment and its interaction with postnatal overfeeding on the cardiovascular system. Pregnant sheep were given daily subcutaneous injections of corn oil (control) or BPA (0.5 mg/kg/day in corn oil) from day 30 to day 90 of gestation. A subset of female offspring of these dams were overfed to increase body weight to ~30% over that of normal fed controls. Cardiovascular function was assessed using non-invasive echocardiography and cuff blood pressure (BP) monitoring at 21 months of age. Ventricular tissue was analyzed for gene expression of cardiac markers of hypertrophy and collagen at the end of the observation period. Prenatal BPA exposure had no significant effect on BP or morphometric measures. However, it increased atrial natriuretic peptide gene expression in the ventricles and reduced collagen expression in the right ventricle. Overfeeding produced a marked increase in body weight and BP. There were compensatory increases in left ventricular area and internal diameter. Prenatal BPA treatment produced a significant increase in interventricular septal thickness when animals were overfed. However, it appeared to block the increase in BP and left ventricular area caused by overfeeding. Taken together, these results suggest that prenatal BPA produces intrinsic changes in the heart that are capable of modulating morphological and functional parameters when animals become obese in later life.

Bisphenol A exposure alters release of immune and developmental modulators and expression of estrogen receptors in human fetal lung fibroblasts

Bisphenol A (BPA) has been shown to exert biological effects through estrogen receptor (ER)-dependent and ER-independent mechanisms. Recent studies suggest that prenatal exposure to BPA may increase the risk of childhood asthma. To investigate the underlying mechanisms in the actions of BPA, human fetal lung fibroblasts (hFLFs) were exposed to varying doses of BPA in culture for 24hr. Effects of BPA on localization and uptake of BPA, cell viability, release of immune and developmental modulators, cellular localization and expression of ERα, ERβ and G-protein coupled estrogen receptor 30 (GPR30), and effects of ERs antagonists on BPA-induced changes in endothelin-1 (ET-1) release were examined. BPA at 0.01-100μmol/L caused no changes in cell viability after 24hr of exposure. hFLFs expresses all three ERs. BPA had no effects on either cellular distribution or protein expression of ERα, however, at 100μmol/L (or 23μmol/L intracellular BPA) increased ERβ protein levels in the cytoplasmic fractions and GPR30 protein levels in the nuclear fractions. These paralleled with increased release of growth differentiation factor-15, decreased phosphorylation of nuclear factor kappa B p65 at serine 536, and decreased release of ET-1, interleukin-6, and interferon gamma-induced protein 10. ERs antagonists had no effects on BPA-induced decrease in ET-1 release. These data suggest that BPA at 100μmol/L altered the release of immune and developmental modulators in hFLFs, which may negatively influence fetal lung development, maturation, and susceptibility to environmental stressors, although the role of BPA in childhood asthma remains to be confirmed in in vivo studies.

Bisphenol A (BPA) Exposure In Utero Leads to Immunoregulatory Cytokine Dysregulation in the Mouse Mammary Gland: A Potential Mechanism Programming Breast Cancer Risk

Bisphenol-A (BPA) is a ubiquitous estrogen-like endocrine disrupting compound (EDC). BPA exposure in utero has been linked to breast cancer and abnormal mammary gland development in mice. The recent rise in incidence of human breast cancer and decreased age of first detection suggests a possible environmental etiology. We hypothesized that developmental programming of carcinogenesis may involve an aberrant immune response. Both innate and adaptive immunity play a role in tumor suppression through cytolytic CD8, NK, and Th1 T-cells. We hypothesized that BPA exposure in utero would lead to dysregulation of both innate and adaptive immunity in the mammary gland. CD1 mice were exposed to BPA in utero during gestation (days 9-21) via osmotic minipump. At 6 weeks, the female offspring were ovariectomized and estradiol was given at 8 weeks. RNA and protein were extracted from the posterior mammary glands, and the mRNA and protein levels were measured by PCR array, qRT-PCR, and western blot. In mouse mammary tissue, BPA exposure in utero significantly decreased the expression of members of the chemokine CXC family (Cxcl2, Cxcl4, Cxcl14, and Ccl20), interleukin 1 (Il1) gene family (Il1β and Il1rn), interleukin 2 gene family (Il7 receptor), and interferon gene family (interferon regulatory factor 9 (Irf9), as well as immune response gene 1 (Irg1). Additionally, BPA exposure in utero decreased Esr1 receptor gene expression and increased Esr2 receptor gene expression. In utero exposure of BPA resulted in significant changes to inflammatory modulators within mammary tissue. We suggest that dysregulation of inflammatory cytokines, both pro-inflammatory and anti-inflammatory, leads to a microenvironment that may promote disordered cell growth through inhibition of the immune response that targets cancer cells.

Prenatal exposure to bisphenol A disrupts adrenal steroidogenesis in adult mouse offspring

The present study sought to determine if prenatal exposure to bisphenol A (BPA) alters adrenal steroidogenesis in adult offspring. Pregnant mice were exposed to BPA (25mg BPA/kg food pellet) via diet from day 7 to the end of pregnancy. At eight weeks of age, offsprings were sacrificed, blood samples and adrenal glands were collected for hormone assays and western blot analysis, respectively. We found that: (1) BPA increased adrenal gland weight in both males and females; (2) although BPA elevated plasma corticosterone levels in both sexes, it stimulated the expression of StAR and cyp11A1, the two rate-limiting factors in the steroidogenic pathway, only in female adrenal glands; and interestingly (3) BPA did not alter plasma ACTH levels or adrenal expression of the key steroidogenic transcription factor SF-1 in either sex. Taken together, the present study provides novel insights into the long-term consequences of developmental BPA exposure on adrenal steroidogenesis.