Studies in experimental autoimmune encephalomyelitis do not support developmental bisphenol a exposure as an environmental factor in increasing multiple sclerosis risk

Endocrine-disrupting chemicals and autoimmune diseases

Endocrine-disrupting chemicals (EDCs) widely exist in people's production and life which have great potential to damage human and animal health. Over the past few decades, growing attention has been paid to the impact of EDCs on human health, as well as immune system. So far, researchers have proved that EDCs (such as bisphenol A (BPA), phthalate, tetrachlorodibenzodioxin (TCDD), etc.) affect human immune function and promotes the occurrence and development of autoimmune diseases (ADs). Therefore, in order to better understand how EDCs affect ADs, we summarized the current knowledge about the impact of EDCs on ADs, and elaborated the potential mechanism of the impact of EDCs on ADs in this review.

Effects of perinatal exposure to bisphenol A or S in EAE model of multiple sclerosis

Epidemiological studies support the idea that multiple sclerosis (MS) is a multifactorial disease, overlapping genetic, epigenetic, and environmental factors. A better definition of environmental risks is critical to understand both etiology and the sex-related differences of MS. Exposure to endocrine-disrupting compounds (EDCs) fully represents one of these risks. EDCs are natural or synthetic exogenous substances (or mixtures) that alter the functions of the endocrine system. Among synthetic EDCs, exposure to bisphenol A (BPA) has been implicated in the etiology of MS, but to date, controversial data has emerged. Furthermore, nothing is known about bisphenol S (BPS), one of the most widely used substitutes for BPA. As exposure to bisphenols will not disappear soon, it is necessary to clarify their role also in this pathological condition defining their role in disease onset and course in both sexes. In this study, we examined, in both sexes, the effects of perinatal exposure to BPA and BPS in one of the most widely used mouse models of MS, experimental autoimmune encephalomyelitis (EAE). Exposure to bisphenols seemed to be particularly deleterious in males. In fact, both BPA- and BPS-treated males showed anticipation of the disease onset and an increased motoneuron loss in the spinal cord. Overall, BPA-treated males also displayed an exacerbation of EAE course and an increase in inflammation markers in the spinal cord. Analyzing the consequences of bisphenol exposure on EAE will help to better understand the role of both xenoestrogens and endogenous estrogens on the sexually dimorphic characteristics of MS.

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.

NF-κB-An Important Player in Xenoestrogen Signaling in Immune Cells

The proper functioning of the immune system is critical for an effective defense against pathogenic factors such as bacteria and viruses. All the cellular processes taking place in an organism are strictly regulated by an intracellular network of signaling pathways. In the case of immune cells, the NF-κB pathway is considered the key signaling pathway as it regulates the expression of more than 200 genes. The transcription factor NF-κB is sensitive to exogenous factors, such as xenoestrogens (XEs), which are compounds mimicking the action of endogenous estrogens and are widely distributed in the environment. Moreover, XE-induced modulation of signaling pathways may be crucial for the proper development of the immune system. In this review, we summarize the effects of XEs on the NF-κB signaling pathway. Based on our analysis, we constructed a model of XE-induced signaling in immune cells and found that in most cases XEs activate NF-κB. Our analysis indicated that the indirect impact of XEs on NF-κB in immune cells is related to the modulation of estrogen signaling and other pathways such as MAPK and JAK/STAT. We also summarize the role of these aspects of signaling in the development and further functioning of the immune system in this paper.

Protective effect of alpha-lipoic acid on bisphenol A-induced learning and memory impairment in developing mice: nNOS and keap1/Nrf2 pathway

The adverse effects of bisphenol A (BPA) on learning and memory may be related with oxidative stress, but the mechanisms are unclear. This study aimed to investigate the mechanism of damaged learning and memory caused by BPA through inducing oxidative stress, as well as to explore whether alpha-lipoic acid (ALA) show a protective action. Female mice were exposed to 0.1 μg/mL BPA, 0.2 μg/mL BPA, 0.6 mg/mL ALA, and 0.2 BPA + ALA through drinking water for 8 weeks. The results showed that ALA protected against the impairment of spatial, recognition, and avoidance memory caused by BPA. ALA replenished the reduce of hippocampus coefficient, serum estradiol (E2) level, and hippocampal neurotransmitters levels induced by BPA. ALA alleviated BPA-induced oxidative stress and hippocampal histological changes. BPA exposure reduced the levels of synaptic structural proteins and PKC/ERK/CREB pathway proteins, and ALA improved these reductions. ALA altered the protein levels of nNOS and keap1/Nrf2 pathway affected by BPA. Our results suggested that impairments of learning and memory caused by BPA was related to the damage of hippocampal synapses mediated by oxidative stress, and ALA protected learning and memory by reducing the oxidative stress induced by BPA through regulating the nNOS and keap1/Nrf2 pathway.

Bisphenol A as a Factor in the Mosaic of Autoimmunity

The population worldwide is largely exposed to bisphenol A (BPA), a commonly used plasticizer, that has a similar molecular structure to endogenous estrogens. Therefore, it is able to influence physiological processes in human body, taking part in the pathophysiology of various endocrinopathies, as well as, cardiovascular, neurological and oncological diseases. BPA has been found to affect the immune system, leading to the development of autoimmunity and allergies, too. In the last few decades, the prevalence of autoimmune diseases has significantly increased, that could be explained by a rising exposure of the population to environmental factors, such as BPA. BPA has been found to play a role in the pathogenesis of systemic autoimmune diseases and also organ-specific autoimmunity (thyroid autoimmunity, diabetes mellitus type 1, myocarditis, inflammatory bowel disease, multiple sclerosis, encephalomyelitis etc), but the results of some studies remain still controversial, so further research is needed.

Interplay Between Endocrine Disruptors and Immunity: Implications for Diseases of Autoreactive Etiology

The sex-bias of disease susceptibility has remained a puzzling aspect of several autoimmune conditions, including post-infection viral autoimmunity. In the last half of the twentieth century, the incidence rate of female-biased autoimmunity has steadily increased independent of medical advances. This has suggested a role for environmental factors, such as endocrine disrupting chemicals, which have been described to interfere with endocrine signaling. Endocrine involvement in the proper function of innate and adaptive immunity has also been defined, however, these two areas have rarely been reviewed in correlation. In addition, studies addressing the effects of endocrine disruptors have reported findings resulting from a broad range of exposure doses, schedules and models. This experimental heterogeneity adds confusion and may mislead the translation of findings to human health. Our work will normalize results across experiments and provide a necessary summary relevant to human exposure. Through a novel approach, we describe how different categories of ubiquitously used environmental endocrine disruptors interfere with immune relevant endocrine signaling and contribute to autoimmunity. We hope this review will guide identification of mechanisms and concentration-dependent EDC effects important not only for the sex-bias of autoimmunity, but also for other conditions of immune dysfunction, including post-infection autoreactivity such as may arise following severe acute respiratory syndrome coronavirus 2, Epstein-Barr virus, Herpes Simplex virus.

Identification of Methylated Gene Biomarkers in Patients with Alzheimer's Disease Based on Machine Learning

Background

Alzheimer's disease (AD) is a neurodegenerative disorder and characterized by the cognitive impairments. It is essential to identify potential gene biomarkers for AD pathology.

Methods

DNA methylation expression data of patients with AD were downloaded from the Gene Expression Omnibus (GEO) database. Differentially methylated sites were identified. The functional annotation analysis of corresponding genes in the differentially methylated sites was performed. The optimal diagnostic gene biomarkers for AD were identified by using random forest feature selection procedure. In addition, receiver operating characteristic (ROC) diagnostic analysis of differentially methylated genes was performed.

Results

A total of 10 differentially methylated sites including 5 hypermethylated sites and 5 hypomethylated sites were identified in AD. There were a total of 8 genes including thioredoxin interacting protein (TXNIP), noggin (NOG), regulator of microtubule dynamics 2 (FAM82A1), myoneurin (MYNN), ankyrin repeat domain 34B (ANKRD34B), STAM-binding protein like 1, ALMalpha (STAMBPL1), cyclin-dependent kinase inhibitor 1C (CDKN1C), and coronin 2B (CORO2B) that correspond to 10 differentially methylated sites. The cell cycle (FDR = 0.0284087) and TGF-beta signaling pathway (FDR = 0.0380372) were the only two significantly enriched pathways of these genes. MYNN was selected as optimal diagnostic biomarker with great diagnostic value. The random forests model could effectively predict AD.

Conclusion

Our study suggested that MYNN could be served as optimal diagnostic biomarker of AD. Cell cycle and TGF-beta signaling pathway may be associated with AD.

Long-term Immunotoxic Effects of Oral Prenatal and Neonatal Atrazine Exposure

Atrazine and its metabolites are present at high concentrations in many water supplies in agro-intensive areas. Because residents in these areas drink water from sources fed from these contaminated supplies, we investigated the long-term immunotoxicity of combined prenatal and neonatal (perinatal) exposure to atrazine via drinking water, on the immune system in mice. At 6 months of age, upon immunization with heat-killed Streptococcus pneumoniae, the serum IgG antibody response against the T independent antigen phosphorylcholine was significantly higher in male, but not female, atrazine-exposed mice as compared with that in untreated controls. No alterations were present in all offspring in the serum antibody response against the T-dependent antigen pneumococcal surface protein A (PspA). ELISpot analysis showed only a small, insignificant reduction in PspA-specific IgG producing splenocytes in atrazine-treated male offspring. Interestingly, upon ex vivo stimulation with anti-CD3 and anti-CD28 antibodies, significant decreases in interleukin (IL)-2, tumor necrosis factor-α, interferon-γ, and IL-17A and a decreasing trend in IL-10 were observed in splenocytes from atrazine-exposed male, but not female mice. Analysis of thymic and splenic cell populations showed no effects of atrazine exposure in either sex. This is the first time that long-term changes in the immune response were observed after a perinatal exposure to atrazine and it demonstrates that these early life exposures can result in permanent changes to the immune system as well as a male bias in these effects.

Environmental exposures during pregnancy: Mechanistic effects on immunity

In human studies, it is well established that exposures during embryonic and fetal development periods can influence immune health. Coupled with genetic predisposition, these exposures can alter lifetime chronic and infectious disease trajectory, and, ultimately, life expectancy. Fortunately, as research advances, mechanisms governing long-term effects of prenatal exposures are coming to light and providing the opportunity for intervention and risk reduction. For instance, human association studies have provided a foundation for the association of prenatal exposure to particulate matter with early immunosuppression and later allergic disease in the offspring. Only recently, the mechanisms mediating this response have been revealed and there is much we have yet to discover. Although cellular immune response is understood for many exposure scenarios, molecular pathways are still unidentified. This review will provide commentary and synthesis of the current literature regarding environmental exposures during pregnancy and mechanisms determining immune outcomes. Shared mechanistic features and current gaps in the state of the science are identified and discussed. To such purpose, we address exposures by their immune effect type: immunosuppression, autoimmunity, inflammation and tissue damage, hypersensitivity, and general immunomodulation.

Effects of continuous bisphenol A exposure from early gestation on 90 day old rat testes function and sperm molecular profiles: A CLARITY-BPA consortium study

Bisphenol A (BPA) is a ubiquitous industrial chemical that has been identified as an endocrine disrupting compound (EDC). There is growing concern that early life exposures to EDCs, such as BPA, can adversely affect the male reproductive tract and function. This study was conducted as part of the Consortium Linking Academic and Regulatory Insights on BPA Toxicity (CLARITY-BPA) to further delineate the toxicities associated with continuous exposure to BPA from early gestation, and to comprehensively examine the elicited effects on testes and sperm. NCTR Sprague Dawley rat dams were gavaged from gestational day (GD) 6 until parturition, and their pups were directly gavaged daily from postnatal day (PND) 1 to 90 with BPA (2.5, 25, 250, 2500, 25,000, 250,000 μg/kg/d) or vehicle control. At PND 90, the testes and sperm were collected for evaluation. The testes were histologically evaluated for altered germ cell apoptosis, sperm production, and altered spermiation. RNA and DNA isolated from sperm were assessed for elicited changes in global mRNA transcript abundance and altered DNA methylation. Effects of BPA were observed in changes in body, testis and epididymis weights only at the highest administered dose of BPA of 250,000 μg/kg/d. Genome-wide transcriptomic and epigenomic analyses failed to detect robust alterations in sperm mRNA and DNA methylation levels. These data indicate that prolonged exposure starting in utero to BPA over a wide range of levels has little, if any, impact on the testes and sperm molecular profiles of 90 day old rats as assessed by the histopathologic, morphometric, and molecular endpoints evaluated.

Epigenetic underpinnings of developmental immunotoxicity and autoimmune disease

The concordance rate for developing autoimmune disease in identical twins is around 50% demonstrating that gene and environmental interactions contribute to disease etiology. The environmental contribution to autoimmune disease is a wide-ranging concept including exposure to immunotoxic environmental chemicals. Because the immune system is immature during development suggests that adult-onset autoimmunity may originate when the immune system is particularly sensitive. Among the pollutants most closely associated with inflammation and/or autoimmunity include Bisphenol-A, mercury, TCDD, and trichloroethylene. These toxicants have been shown to impart epigenetic changes (e.g., DNA methylation) that may alter immune function and promote autoreactivity. Here we review these autoimmune-promoting toxicants and their relation to immune cell epigenetics both in terms of adult and developmental exposure.

Bisphenol A Does Not Mimic Estrogen in the Promotion of the In Vitro Response of Murine Dendritic Cells to Toll-Like Receptor Ligands

Sex hormones affect immune responses and might promote autoimmunity. Endocrine disrupting chemicals such as bisphenol A (BPA) may mimic their immune effects. Conventional dendritic cells (cDCs) are pivotal initiators of immune responses upon activation by danger signals coming from pathogens or distressed tissues through triggering of the Toll-like receptors (TLRs). We generated in vitro murine cDCs in the absence of estrogens and measured the effects of exogenously added estrogen or BPA on their differentiation and activation by the TLR ligands LPS and CpG. Estrogen enhanced the differentiation of GM-CSF-dependent cDCs from bone marrow precursors in vitro, and the selective estrogen receptor modulators (SERMs) tamoxifen and fulvestrant blocked these effects. Moreover, estrogen augmented the upregulation of costimulatory molecules and proinflammatory cytokines (IL-12p70 and TNFα) upon stimulation by TLR9 ligand CpG, while the response to LPS was less estrogen-dependent. These effects are partially explained by an estrogen-dependent regulation of TLR9 expression. BPA did not promote cDC differentiation nor activation upon TLR stimulation. Our results suggest that estrogen promotes immune responses by increasing DC activation, with a preferential effect on TLR9 over TLR4 stimulation, and highlight the influence of estrogens in DC cultures, while BPA does not mimic estrogen in the DC functions that we tested.

Gestational bisphenol-A exposure lowers the threshold for autoimmunity in a model of multiple sclerosis

Environmental and hormonal factors are implicated in dysimmunity in multiple sclerosis. We investigated whether bisphenol-A, a prominent contaminant with endocrine-disrupting capabilities, altered susceptibility in an inflammatory model of multiple sclerosis. We found that gestational, but not adult, exposure to bisphenol-A increased the development of experimental autoimmune encephalomyelitis in adulthood in male, but not female, mice when a suboptimal disease-inducing immunization was used. Gestational bisphenol-A in male mice primed macrophages in adulthood and raised granulocyte-colony stimulating factor and neutrophil counts/activity postsuboptimal immunization. Neutralizing granulocyte-colony stimulating factor blocked susceptibility to disease in bisphenol-A mice. Early life exposure to bisphenol-A may represent an environmental consideration in multiple sclerosis.

Single nucleotide polymorphisms in the FOXP3 gene are associated with increased risk of relapsing-remitting multiple sclerosis

BACKGROUND

Although Multiple Sclerosis (MS) is an autoimmune multifactorial disease with unknown etiology, various genetic and environmental factors are known to contribute to the pathogenesis of the disease.

OBJECTIVE

Recent studies have confirmed that the suppressive function of regulatory T cells (T (reg)) is impaired in MS patients and that the FOXP3 gene is a crucial transcription factor in the regulation of CD4+CD25+FOXP3+ Treg cells. Polymorphisms in the promoter region of the FOXP3 gene may alter the gene expression level and, therefore, contribute to the disease susceptibility.

METHODS

The present study aimed to investigate the possible association between single nucleotide polymorphisms (SNPs) rs3761548 and rs2232365 in the FOXP3 gene and predisposition to MS. We conducted a case-control study on 410 patients with sporadic MS and 446 healthy controls. Genotyping was performed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).

RESULTS

Significant differences in distribution of both rs3761548 and rs2232365 A allele were found in MS patients in comparison to controls. Haplotype frequencies were also different among the studied groups. The A-A and C-G haplotype blocks showed a significant difference between case and controls.

CONCLUSION

we have provided further evidence for the association between genetic variations and haplotypes in FOXP3 and MS in Iranian population.

Developmental Bisphenol A Exposure Modulates Immune-Related Diseases

Bisphenol A (BPA), used in polycarbonate plastics and epoxy resins, has a widespread exposure to humans. BPA is of concern for developmental exposure resulting in immunomodulation and disease development due to its ability to cross the placental barrier and presence in breast milk. BPA can use various mechanisms to modulate the immune system and affect diseases, including agonistic and antagonistic effects on many receptors (e.g., estrogen receptors), epigenetic modifications, acting on cell signaling pathways and, likely, the gut microbiome. Immune cell populations and function from the innate and adaptive immune system are altered by developmental BPA exposure, including decreased T regulatory (Treg) cells and upregulated pro- and anti-inflammatory cytokines and chemokines. Developmental BPA exposure can also contribute to the development of type 2 diabetes mellitus, allergy, asthma and mammary cancer disease by altering immune function. Multiple sclerosis and type 1 diabetes mellitus may also be exacerbated by BPA, although more research is needed. Additionally, BPA analogs, such as bisphenol S (BPS), have been increasing in use, and currently, little is known about their immune effects. Therefore, more studies should be conducted to determine if developmental exposure BPA and its analogs modulate immune responses and lead to immune-related diseases.

Environmental estrogen bisphenol A and autoimmunity

Over the past few years, there has been evidence of the increasing prevalence of autoimmune diseases. Autoimmune diseases consist of many complex disorders of unknown etiology resulting in immune responses to self-antigens. The immune system, and its function, is under complex and integrated control and its disruption can be triggered by multiple factors. Autoimmunity development is influenced by multiple factors and is thought to be a result of interactions between genetic and environmental factors. Here, we review the role of a specific environmental factor, bisphenol A (BPA), in the pathogenesis of autoimmune diseases. BPA belongs to the group of environmental estrogens that have been identified as risk factors involved in the development of autoimmune diseases.

Epigenetic Regulation of Non-Lymphoid Cells by Bisphenol A, a Model Endocrine Disrupter: Potential Implications for Immunoregulation

Endocrine disrupting chemicals (EDC) abound in the environment since many compounds are released from chemical, agricultural, pharmaceutical, and consumer product industries. Many of the EDCs such as Bisphenol A (BPA) have estrogenic activity or interfere with endogenous sex hormones. Experimental studies have reported a positive correlation of BPA with reproductive toxicity, altered growth, and immune dysregulation. Although the precise relevance of these studies to the environmental levels is unclear, nevertheless, their potential health implications remain a concern. One possible mechanism by which BPA can alter genes is by regulating epigenetics, including microRNA, alteration of methylation, and histone acetylation. There is now wealth of information on BPA effects on non-lymphoid cells and by comparison, paucity of data on effects of BPA on the immune system. In this mini review, we will highlight the BPA regulation of estrogen receptor-mediated immune cell functions and in different inflammatory conditions. In addition, BPA-mediated epigenetic regulation of non-lymphoid cells is emphasized. We recognize that most of these studies are on non-lymphoid cells, and given that BPA also affects the immune system, it is plausible that BPA could have similar epigenetic regulation in immune cells. It is hoped that this review will stimulate studies in this area to ascertain whether or not BPA epigenetically regulates the cells of the immune system.

The role of genetics in estrogen responses: a critical piece of an intricate puzzle

The estrogens are female sex hormones that are involved in a variety of physiological processes, including reproductive development and function, wound healing, and bone growth. They are mainly known for their roles in reproductive tissues--specifically, 17β-estradiol (E2), the primary estrogen, which is secreted by the ovaries and induces cellular proliferation and growth of the uterus and mammary glands. In addition to the role of estrogens in promoting tissue growth and development during normal physiological states, they have a well-established role in determining susceptibility to disease, particularly cancer, in reproductive tissues. The responsiveness of various tissues to estrogen is genetically controlled, with marked quantitative variation observed across multiple species, including humans. This variation presents both researchers and clinicians with a veritable physiological puzzle, the pieces of which--many of them unknown--are complex and difficult to fit together. Although genetics is known to play a major role in determining sensitivity to estrogens, there are other factors, including parent of origin and the maternal environment, that are intimately linked to heritable phenotypes but do not represent genotype, per se. The objectives of this review article were to summarize the current knowledge of the role of genotype, and uterine and neonatal environments, in phenotypic variation in the response to estrogens; to discuss recent findings and the potential mechanisms involved; and to highlight exciting research opportunities for the future.

Gestational bisphenol A exposure and testis development

Virtually all humans are exposed to bisphenol A (BPA). Since BPA can act as a ligand for estrogen receptors, potential hazardous effects of BPA should be evaluated in the context of endogenous estrogenic hormones. Because estrogen is metabolized in the placenta, developing fetuses are normally exposed to very low endogenous estrogen levels. BPA, on the other hand, passes through the placenta and might have distinct adverse consequences during the sensitive stages of fetal development. Testicular gametogenesis and steroidogenesis begin early during fetal development. These processes are sensitive to estrogens and play a role in determining the number of germ stem cells, sperm count, and male hormone levels in adulthood. Although studies have shown a correlation between BPA exposure and perturbed reproduction, a clear consensus has yet to be established as to whether current human gestational BPA exposure results in direct adverse effects on male genital development and reproduction. However, studies in animals and in vitro have provided direct evidence for the ability of BPA exposure to influence male reproductive development. This review discusses the current knowledge of potential effects of BPA exposure on male reproductive health and whether gestational exposure adversely affects testis development.

Coexposure to phytoestrogens and bisphenol a mimics estrogenic effects in an additive manner

Endocrine-disrupting chemicals (EDC) are abundant in our environment. A number of EDCs, including bisphenol A (BPA) can bind to the estrogen receptors (ER), ERα and ERβ, and may contribute to estrogen-linked diseases such as breast cancer. Early exposure is of particular concern; many EDCs cross the placenta and infants have measurable levels of, eg, BPA. In addition, infants are frequently fed soy-based formula (SF) that contains phytoestrogens. Effects of combined exposure to xeno- and phytoestrogens are poorly studied. Here, we extensively compared to what extent BPA, genistein, and an extract of infant SF mimic estrogen-induced gene transcription and cell proliferation. We investigated ligand-specific effects on ER activation in HeLa-ERα and ERβ reporter cells; on proliferation, genome-wide gene regulation and non-ER-mediated effects in MCF7 breast cancer cells; and how coexposure influenced these effects. The biological relevance was explored using enrichment analyses of differentially regulated genes and clustering with clinical breast cancer profiles. We demonstrate that coexposure to BPA and genistein, or SF, results in increased functional and transcriptional estrogenic effects. Using statistical modeling, we determine that BPA and phytoestrogens act in an additive manner. The proliferative and transcriptional effects of the tested compounds mimic those of 17β-estradiol, and are abolished by cotreatment with an ER antagonist. Gene expression profiles induced by each compound clustered with poor prognosis breast cancer, indicating that exposure may adversely affect breast cancer prognosis. This study accentuates that coexposure to BPA and soy-based phytoestrogens results in additive estrogenic effects, and may contribute to estrogen-linked diseases, including breast cancer.

Environmental factors acting during development to influence MS risk: insights from animal studies

Multiple sclerosis (MS) is an autoimmune demyelinating disease of the central nervous system with an increasing incidence in females. Epidemiological data strongly implicate environmental factors acting at the population level during gestation, childhood and adulthood in the increasing incidence of MS. Several such factors are implicated in disease risk, but their causality remains unproven, while other factors remain unknown. An understanding of the risk factors acting during development is particularly limited. Animal studies could potentially bridge the gap between observational epidemiology and clinical intervention, providing not only direct evidence of causality for a given environmental agent, but also an opportunity to dissect the underlying molecular mechanisms. Given a rodent's short gestational and developmental period, the effects of developmental exposure can also be readily addressed. Nonetheless, studies in this area so far are few. In this review, we summarize the insights gleaned from studies that test environmental influences in animal models of MS, with a particular focus on gestational and early life exposures.