Sex differences in the effects of prenatal bisphenol A exposure on autism-related genes and their relationships with the hippocampus functions

Linking Environmental Chemicals to Neuroinflammation and Autism Spectrum Disorder: Mechanisms and Implications for Prevention

This article explores the potential link between endocrine-disrupting chemicals (EDCs), neuroinflammation, and the development of autism spectrum disorder (ASD). Neuroinflammation refers to the immune system's response to injury, infection, or disease in the central nervous system. Studies have shown that exposure to EDCs, such as bisphenol A and phthalates, can disrupt normal immune function in the brain, leading to chronic or excessive neuroinflammation. This disruption of immune function can contribute to developing neurological disorders, including ASD. Furthermore, EDCs may activate microglia, increasing pro-inflammatory cytokine production and astroglia-mediated oxidative stress, exacerbating neuroinflammation. EDCs may also modulate the epigenetic profile of cells by methyltransferase expression, thereby affecting neurodevelopment. This article also highlights the importance of reducing exposure to EDCs and advocating for policies and regulations restricting their use. Further research is needed to understand better the mechanisms underlying the link between EDCs, neuroinflammation, and ASD and to develop new treatments for ASD.

Role of Enzymes Capable of Transporting Phosphatidylserine in Brain Development and Brain Diseases

Phosphatidylserine (PS) is a common type of phospholipid, typically located in the inner leaflet of the cell membrane, especially abundant in the nervous system. It is an important component of the neuronal membrane and is considered to play a regulatory role in various brain functions, including memory and emotional stability, because its exposure to the outer leaflet of the neuronal membrane can result in abnormalities in various neurobiological processes such as synaptic transmission and neuronal apoptosis. Recently, research on two types of membrane proteins that synergistically mediate the transmembrane transport of phospholipid molecules in eukaryotic cells has become more in-depth and detailed. This review mainly explores the regulation of the expression of phosphatidylserine transporters and their impact on brain development and diseases.

Male autism spectrum disorder is linked to brain aromatase disruption by prenatal BPA in multimodal investigations and 10HDA ameliorates the related mouse phenotype

Male sex, early life chemical exposure and the brain aromatase enzyme have been implicated in autism spectrum disorder (ASD). In the Barwon Infant Study birth cohort (n = 1074), higher prenatal maternal bisphenol A (BPA) levels are associated with higher ASD symptoms at age 2 and diagnosis at age 9 only in males with low aromatase genetic pathway activity scores. Higher prenatal BPA levels are predictive of higher cord blood methylation across the CYP19A1 brain promoter I.f region (P = 0.009) and aromatase gene methylation mediates (P = 0.01) the link between higher prenatal BPA and brain-derived neurotrophic factor methylation, with independent cohort replication. BPA suppressed aromatase expression in vitro and in vivo. Male mice exposed to mid-gestation BPA or with aromatase knockout have ASD-like behaviors with structural and functional brain changes. 10-hydroxy-2-decenoic acid (10HDA), an estrogenic fatty acid alleviated these features and reversed detrimental neurodevelopmental gene expression. Here we demonstrate that prenatal BPA exposure is associated with impaired brain aromatase function and ASD-related behaviors and brain abnormalities in males that may be reversible through postnatal 10HDA intervention.

Antifungal climbazole alters androgenic pathways in mammalian cells

Among antifungal agents used in pharmaceuticals and personal care products, the synthetic azole climbazole (CBZ; 1-(4-Chlorophenoxy)-1-(imidazol-1-yl)-3,3-dimethylbutan-2-one) acts on the fungus Malassezia. Despite concerns surrounding its effects on health, based on alterations to reproduction and steroidogenesis found in fish, little is known about its mechanism of action as an endocrine disrupting chemical (EDC) in mammalian cells. In this study, using OECD test guidelines, we investigated the effects of CBZ (i) in H295R cells, on the production of estradiol and testosterone, as well as intermediate metabolites in steroidogenesis pathway, and (ii) in HeLa9903 and AR-EcoScreen cell lines, on the transactivation of estrogen and androgen receptors. Our results are the first evidence in H295R cells, that CBZ treatment (from 0.3 μM) decreased secreted levels of testosterone and estradiol. This was associated with reduced 17α-hydroxypregnenolone and 17α-hydroxyprogesterone levels. The altered levels of these metabolites were associated with a decrease in cytochrome P450 17α-hydroxylase/17,20-lyase (Cyp17A1) activity without any effect on its protein level. CBZ was also found to exert antagonistic effects toward androgen and estrogen α receptors. These results give insights into the toxicological mechanism of action of CBZ. Many azoles share structural similarities; therefore, caution should be adopted due to their potential toxicity.

Transcriptomics analysis reveals potential regulatory role of nSMase2 (Smpd3) in nervous system development and function of middle-aged mouse brains

Neutral sphingomyelinase-2 (nSMase2), gene name sphingomyelin phosphodiesterase-3 (Smpd3), is a key regulatory enzyme responsible for generating the sphingolipid ceramide. The function of nSMase2 in the brain is still controversial. To better understand the functional roles of nSMase2 in the aging mouse brain, we applied RNA-seq analysis, which identified a total of 1462 differentially abundant mRNAs between +/fro and fro/fro, of which 891 were increased and 571 were decreased in nSMase2-deficient mouse brains. The most strongly enriched GO and KEGG annotation terms among transcripts increased in fro/fro mice included synaptogenesis, synapse development, synaptic signaling, axon development, and axonogenesis. Among decreased transcripts, enriched annotations included ribosome assembly and mitochondrial protein complex functions. KEGG analysis of decreased transcripts also revealed overrepresentation of annotations for Alzheimer's disease (AD), Parkinson's disease (PD), and Huntington disease (HD). Ingenuity Pathway Analysis (IPA) tools predicted lower susceptibility to these neurodegenerative disorders, as well as predictions agreeing with stronger synaptic function, learning, and memory in fro/fro mice. The IPA tools identified signaling proteins, epigenetic regulators, and microRNAs as likely upstream regulators of the broader set of genes encoding the affected transcripts. It also revealed 16 gene networks, each linked to biological processes identified as overrepresented annotations among the affected transcripts by multiple analysis methods. Therefore, the analysis of these RNA-seq data indicates that nSMase2 impacts synaptic function and neural development, and may contribute to the onset and development of neurodegenerative diseases in middle-aged mice.

Distinct epigenetic modulation of differentially expressed genes in the adult mouse brain following prenatal exposure to low-dose bisphenol A

Bisphenol A (BPA) is a common component in the manufacture of daily plastic consumer goods. Recent studies have suggested that prenatal exposure to BPA can increase the susceptibility of offspring to mental illness, although the underlying mechanisms remain unclear. In this study, we performed transcriptomic and epigenomic profiling in the adult mouse brain following prenatal exposure to low-dose BPA. We observed a sex-specific transcriptional dysregulation in the cortex, with more significant differentially expressed genes was observed in adult cortex from male offspring. Moreover, the upregulated genes primarily influenced neuronal functions, while the downregulated genes were significantly associated with energy metabolism pathways. More evidence supporting impaired mitochondrial function included a decreased ATP level and a reduced number of mitochondria in the cortical neuron of the BPA group. We further investigated the higher-order chromatin regulatory patterns of DEGs by incorporating published Hi-C data. Interestingly, we found that upregulated genes exhibited more distal interactions with multiple enhancers, while downregulated genes displayed relatively short-range interactions among adjacent genes. Our data further revealed decreased H3K9me3 signal on the distal enhancers of upregulated genes, whereas increased DNA methylation and H3K27me3 signals on the promoters of downregulated genes. In summary, our study provides compelling evidence for the potential health risks associated with prenatal exposure to BPA, and uncovers sex-specific transcriptional changes with a complex interplay of multiple epigenetic mechanisms.

Implications of Prenatal Exposure to Endocrine-Disrupting Chemicals in Offspring Development: A Narrative Review

During the last decades, endocrine-disrupting chemicals (EDCs) have attracted the attention of the scientific community, as a result of a deepened understanding of their effects on human health. These compounds, which can reach populations through the food chain and a number of daily life products, are known to modify the activity of the endocrine system. Regarding vulnerable groups like pregnant mothers, the potential damage they can cause increases their importance, since it is the health of two lives that is at risk. EDCs can affect the gestation process, altering fetal development, and eventually inducing the appearance of many disorders in their childhood and/or adulthood. Because of this, several of these substances have been studied to clarify the influence of their prenatal exposure on the cognitive and psychomotor development of the newborn, together with the appearance of non-communicable diseases and other disorders. The most novel research on the subject has been gathered in this narrative review, with the aim of clarifying the current knowledge on the subject. EDCs have shown, through different studies involving both animal and human investigation, a detrimental effect on the development of children exposed to the during pregnancy, sometimes with sex-specific outcomes. However, some other studies have failed to find these associations, which highlights the need for deeper and more rigorous research, that will provide an even more solid foundation for the establishment of policies against the extended use of these chemicals.

Sex-specific impacts of prenatal bisphenol A exposure on genes associated with cortical development, social behaviors, and autism in the offspring's prefrontal cortex

BACKGROUND

Recent studies have shown that prenatal BPA exposure altered the transcriptome profiles of autism-related genes in the offspring's hippocampus, disrupting hippocampal neuritogenesis and causing male-specific deficits in learning. However, the sex differences in the effects of prenatal BPA exposure on the developing prefrontal cortex, which is another brain region highly implicated in autism spectrum disorder (ASD), have not been investigated.

METHODS

We obtained transcriptome data from RNA sequencing analysis of the prefrontal cortex of male and female rat pups prenatally exposed to BPA or control and reanalyzed. BPA-responsive genes associated with cortical development and social behaviors were selected for confirmation by qRT-PCR analysis. Neuritogenesis of primary cells from the prefrontal cortex of pups prenatally exposed to BPA or control was examined. The social behaviors of the pups were assessed using the two-trial and three-chamber tests. The male-specific impact of the downregulation of a selected BPA-responsive gene (i.e., Sema5a) on cortical development in vivo was interrogated using siRNA-mediated knockdown by an in utero electroporation technique.

RESULTS

Genes disrupted by prenatal BPA exposure were associated with ASD and showed sex-specific dysregulation. Sema5a and Slc9a9, which were involved in neuritogenesis and social behaviors, were downregulated only in males, while Anxa2 and Junb, which were also linked to neuritogenesis and social behaviors, were suppressed only in females. Neuritogenesis was increased in males and showed a strong inverse correlation with Sema5a and Slc9a9 expression levels, whereas, in the females, neuritogenesis was decreased and correlated with Anxa2 and Junb levels. The siRNA-mediated knockdown of Sema5a in males also impaired cortical development in utero. Consistent with Anxa2 and Junb downregulations, deficits in social novelty were observed only in female offspring but not in males.

CONCLUSION

This is the first study to show that prenatal BPA exposure dysregulated the expression of ASD-related genes and functions, including cortical neuritogenesis and development and social behaviors, in a sex-dependent manner. Our findings suggest that, besides the hippocampus, BPA could also exert its adverse effects through sex-specific molecular mechanisms in the offspring's prefrontal cortex, which in turn would lead to sex differences in ASD-related neuropathology and clinical manifestations, which deserves further investigation.

Giftedness and atypical sexual differentiation: enhanced perceptual functioning through estrogen deficiency instead of androgen excess

Syndromic autism spectrum conditions (ASC), such as Klinefelter syndrome, also manifest hypogonadism. Compared to the popular Extreme Male Brain theory, the Enhanced Perceptual Functioning model explains the connection between ASC, savant traits, and giftedness more seamlessly, and their co-emergence with atypical sexual differentiation. Overexcitability of primary sensory inputs generates a relative enhancement of local to global processing of stimuli, hindering the abstraction of communication signals, in contrast to the extraordinary local information processing skills in some individuals. Weaker inhibitory function through gamma-aminobutyric acid type A (GABAA) receptors and the atypicality of synapse formation lead to this difference, and the formation of unique neural circuits that process external information. Additionally, deficiency in monitoring inner sensory information leads to alexithymia (inability to distinguish one's own emotions), which can be caused by hypoactivity of estrogen and oxytocin in the interoceptive neural circuits, comprising the anterior insular and cingulate gyri. These areas are also part of the Salience Network, which switches between the Central Executive Network for external tasks and the Default Mode Network for self-referential mind wandering. Exploring the possibility that estrogen deficiency since early development interrupts GABA shift, causing sensory processing atypicality, it helps to evaluate the co-occurrence of ASC with attention deficit hyperactivity disorder, dyslexia, and schizophrenia based on phenotypic and physiological bases. It also provides clues for understanding the common underpinnings of these neurodevelopmental disorders and gifted populations.

Endocrine disrupting chemical Bisphenol A and its association with cancer mortality: a prospective cohort study of NHANES

Introduction

There is evidence suggesting that Bisphenol A (BPA) is associated with increased all-cause mortality in adults. However, the specific nature of the relationship between BPA exposure and cancer mortality remains relatively unexplored.

Methods

The National Health and Nutrition Examination Survey (NHANES) dataset was used to recruit participants. Urinary BPA was assessed using liquid chromatography-mass spectrum (LC-MS). Through the use of multivariable Cox proportional hazard regressions and constrained cubic splines, the relationships between urine BPA and death from all causes and cancer were investigated.

Results

This study has a total of 8,035 participants, and 137 died from cancers after a 7.5-year follow-up. The median level of BPA was 2.0 g/mL. Urinary BPA levels were not independently associated with all-cause mortality. For cancer mortality, the second quartile's multivariable-adjusted hazard ratio was 0.51 (95% confidence interval: 0.30 to 0.86; p = 0.011) compared to the lowest quartile. The restricted cubic splines showed that the association was nonlinear (p for nonlinearity = 0.028) and the inflection point was 1.99 ng/mL.

Conclusion

Urinary BPA exposure was U-shaped associated with the risk of cancer mortality, and a lower level of BPA less than 1.99 ng/mL was associated with a higher risk of cancer mortality.

The association between prenatal bisphenol F exposure and infant neurodevelopment: The mediating role of placental estradiol

BACKGROUND

There are limited population studies on the neurodevelopmental effects of bisphenol F (BPF), a substitute for bisphenol A. Furthermore, the role of placental estradiol as a potential mediator linking these two factors remains unclear.

OBJECTIVE

To examine the association between maternal prenatal BPF exposure and infant neurodevelopment in a prospective cohort study and to explore the mediating effects of placental estradiol between BPF exposure and neurodevelopment in a nested case-control study.

METHODS

The prospective cohort study included 1077 mother-neonate pairs from the Wuhu city cohort study in China. Maternal BPF was determined using the liquid/liquid extraction and Ultra-performance liquid chromatography tandem mass spectrometry method. Children's neurodevelopment was assessed at ages 3, 6, and 12 months using Ages and Stages Questionnaires. The nested case-control study included 150 neurodevelopmental delay cases and 150 healthy controls. Placental estradiol levels were measured using enzyme-linked immunosorbent assay kits. Generalized estimating equation models and robust Poisson regression models were used to examine the associations between BPF exposure and children's neurodevelopment. In the nested case-control study, causal mediation analysis was conducted to assess the role of placental estradiol as a mediator in multivariate models.

RESULTS

In the prospective cohort study, the pregnancy-average BPF concentration was positively associated with developmental delays in gross-motor, fine-motor, and problem-solving ( ORtotal ASQ: 1.14(1.05, 1.25), ORgross-motor: 1.22(1.10, 1.36), ORfine-motor: 1.19(1.07, 1.31), ORproblem-solving: 1.11(1.01, 1.23)). After sex-stratified analyses, pregnancy-average BPF concentration was associated with an increased risk of neurodevelopmental delays in the gross-motor (ORgross-motor:1.30(1.12, 1.51)) and fine-motor (ORfine-motor: 1.22(1.06, 1.40)) domains in boys. In the nested case-control study, placental estradiol mediated 16.6% (95%CI: 4.4%, 35.0%) of the effects of prenatal BPF exposure on developmental delay.

CONCLUSIONS

Our study supports an inverse relationship between prenatal BPF exposure and child neurodevelopment in infancy, particularly in boys. Decreased placental estradiol may be an underlying biological pathway linking prenatal BPF exposure to neurodevelopmental delay in offspring.

Mitigating the impact of bisphenol A exposure on mortality: Is diet the key? A cohort study based on NHANES

Bisphenol A (BPA) is a widespread environmental pollutant linked to detrimental effects on human health and reduced life expectancy following chronic exposure. This prospective cohort study aimed to examine the association between BPA exposure and mortality in American adults and to explore the potential mitigating effects of dietary quality on BPA-related mortality. This study utilized data from 8761 American adults in the 2003-2016 National Health and Nutrition Examination Survey (NHANES). Urinary BPA levels were employed to assess BPA exposure, and dietary quality was evaluated using the Healthy Eating Index-2015 (HEI-2015). All-cause, cardiovascular disease (CVD), and cancer mortality statuses were determined until December 31, 2019, resulting in a cumulative follow-up of 80,564 person-years. The results showed that the highest tertile of urinary BPA levels corresponded to a 36% increase in all-cause mortality and a 62% increase in CVD mortality compared to the lowest tertile. In contrast, the highest tertile of HEI-2015 scores was associated with a 29% reduction in all-cause mortality relative to the lowest tertile. Although no significant interaction was found between HEI-2015 scores and urinary BPA levels concerning mortality, the association between HEI-2015 scores and both all-cause and CVD mortality was statistically significant at low urinary BPA levels. Continuous monitoring of BPA exposure is crucial for evaluating its long-term adverse health effects. Improving dietary quality can lower all-cause mortality and decrease the risk of all-cause and CVD mortality at low BPA exposure levels. However, due to the limited protective effect of dietary quality against BPA exposure, minimizing BPA exposure remains a vital goal.

[Association between maternal gestational diabetes mellitus and the risk of autism spectrum disorder in offspring]

OBJECTIVES

To explore the association between maternal gestational diabetes mellitus (GDM) exposure and the development of autism spectrum disorder (ASD) in offspring.

METHODS

A case-control study was conducted, recruiting 221 children with ASD and 400 healthy children as controls. Questionnaires and interviews were used to collect information on general characteristics of the children, socio-economic characteristics of the family, maternal pregnancy history, and maternal disease exposure during pregnancy. Multivariate logistic regression analysis was used to investigate the association between maternal GDM exposure and the development of ASD in offspring. The potential interaction between offspring gender and maternal GDM exposure on the development of ASD in offspring was explored.

RESULTS

The proportion of maternal GDM was significantly higher in the ASD group compared to the control group (16.3% vs 9.4%, P=0.014). After adjusting for variables such as gender, gestational age, mode of delivery, parity, and maternal education level, maternal GDM exposure was a risk factor for ASD in offspring (OR=2.18, 95%CI: 1.04-4.54, P=0.038). On the basis of adjusting the above variables, after further adjusting the variables including prenatal intake of multivitamins, folic acid intake in the first three months of pregnancy, and assisted reproduction the result trend did not change, but no statistical significance was observed (OR=1.94, 95%CI: 0.74-5.11, P=0.183). There was an interaction between maternal GDM exposure and offspring gender on the development of ASD in offspring (P<0.001). Gender stratified analysis showed that only in male offspring of mothers with GDM, the risk of ASD was significantly increased (OR=3.67, 95%CI: 1.16-11.65, P=0.027).

CONCLUSIONS

Maternal GDM exposure might increase the risk of ASD in offspring. There is an interaction between GDM exposure and offspring gender in the development of ASD in offspring.

Dysfunction of the medial prefrontal cortex contributes to BPA-induced depression- and anxiety-like behavior in mice

Bisphenol A (BPA), a well-known environmental endocrine disruptor, has been implicated in anxiety-like behavior. But the neural mechanism remains elusive. Herein, we found that mice exposed to 0.5 mg/kg/day BPA chronically from postnatal days (PND) 21 to PND 80 exhibited depression- and anxiety-like behavior. Further study showed that medial prefrontal cortex (mPFC), was associated with BPA-induced depression- and anxiety-like behavior, as evidenced by decreased c-fos expression in mPFC of BPA-exposed mice. Both the morphology and function of glutamatergic neurons (also called pyramidal neurons) in mPFC of mice were impaired following BPA exposure, characterized by reduced primary branches, weakened calcium signal, and decreased mEPSC frequency. Importantly, optogenetic activation of the pyramidal neurons in mPFC greatly reversed BPA-induced depression- and anxiety-like behavior in mice. Furthermore, we reported that microglial activation in mPFC of mice may also have a role in BPA-induced depression- and anxiety-like behavior. Taken together, the results indicated that mPFC is the brain region that is greatly damaged by BPA exposure and is associated with BPA-induced depression- and anxiety-like behavior. The study thus provides new insights into BPA-induced neurotoxicity and behavioral changes.

Screening autism-associated environmental factors in differentiating human neural progenitors with fractional factorial design-based transcriptomics

Research continues to identify genetic variation, environmental exposures, and their mixtures underlying different diseases and conditions. There is a need for screening methods to understand the molecular outcomes of such factors. Here, we investigate a highly efficient and multiplexable, fractional factorial experimental design (FFED) to study six environmental factors (lead, valproic acid, bisphenol A, ethanol, fluoxetine hydrochloride and zinc deficiency) and four human induced pluripotent stem cell line derived differentiating human neural progenitors. We showcase the FFED coupled with RNA-sequencing to identify the effects of low-grade exposures to these environmental factors and analyse the results in the context of autism spectrum disorder (ASD). We performed this after 5-day exposures on differentiating human neural progenitors accompanied by a layered analytical approach and detected several convergent and divergent, gene and pathway level responses. We revealed significant upregulation of pathways related to synaptic function and lipid metabolism following lead and fluoxetine exposure, respectively. Moreover, fluoxetine exposure elevated several fatty acids when validated using mass spectrometry-based metabolomics. Our study demonstrates that the FFED can be used for multiplexed transcriptomic analyses to detect relevant pathway-level changes in human neural development caused by low-grade environmental risk factors. Future studies will require multiple cell lines with different genetic backgrounds for characterising the effects of environmental exposures in ASD.

Epigenetic Gene-Regulatory Loci in Alu Elements Associated with Autism Susceptibility in the Prefrontal Cortex of ASD

Alu elements are transposable elements that can influence gene regulation through several mechanisms; nevertheless, it remains unclear whether dysregulation of Alu elements contributes to the neuropathology of autism spectrum disorder (ASD). In this study, we characterized transposable element expression profiles and their sequence characteristics in the prefrontal cortex tissues of ASD and unaffected individuals using RNA-sequencing data. Our results showed that most of the differentially expressed transposable elements belong to the Alu family, with 659 loci of Alu elements corresponding to 456 differentially expressed genes in the prefrontal cortex of ASD individuals. We predicted cis- and trans-regulation of Alu elements to host/distant genes by conducting correlation analyses. The expression level of Alu elements correlated significantly with 133 host genes (cis-regulation, adjusted p < 0.05) associated with ASD as well as the cell survival and cell death of neuronal cells. Transcription factor binding sites in the promoter regions of differentially expressed Alu elements are conserved and associated with autism candidate genes, including RORA. COBRA analyses of postmortem brain tissues showed significant hypomethylation in global methylation analyses of Alu elements in ASD subphenotypes as well as DNA methylation of Alu elements located near the RNF-135 gene (p < 0.05). In addition, we found that neuronal cell density, which was significantly increased (p = 0.042), correlated with the expression of genes associated with Alu elements in the prefrontal cortex of ASD. Finally, we determined a relationship between these findings and the ASD severity (i.e., ADI-R scores) of individuals with ASD. Our findings provide a better understanding of the impact of Alu elements on gene regulation and molecular neuropathology in the brain tissues of ASD individuals, which deserves further investigation.

Microplastic sources, formation, toxicity and remediation: a review

Microplastic pollution is becoming a major issue for human health due to the recent discovery of microplastics in most ecosystems. Here, we review the sources, formation, occurrence, toxicity and remediation methods of microplastics. We distinguish ocean-based and land-based sources of microplastics. Microplastics have been found in biological samples such as faeces, sputum, saliva, blood and placenta. Cancer, intestinal, pulmonary, cardiovascular, infectious and inflammatory diseases are induced or mediated by microplastics. Microplastic exposure during pregnancy and maternal period is also discussed. Remediation methods include coagulation, membrane bioreactors, sand filtration, adsorption, photocatalytic degradation, electrocoagulation and magnetic separation. Control strategies comprise reducing plastic usage, behavioural change, and using biodegradable plastics. Global plastic production has risen dramatically over the past 70 years to reach 359 million tonnes. China is the world's top producer, contributing 17.5% to global production, while Turkey generates the most plastic waste in the Mediterranean region, at 144 tonnes per day. Microplastics comprise 75% of marine waste, with land-based sources responsible for 80-90% of pollution, while ocean-based sources account for only 10-20%. Microplastics induce toxic effects on humans and animals, such as cytotoxicity, immune response, oxidative stress, barrier attributes, and genotoxicity, even at minimal dosages of 10 μg/mL. Ingestion of microplastics by marine animals results in alterations in gastrointestinal tract physiology, immune system depression, oxidative stress, cytotoxicity, differential gene expression, and growth inhibition. Furthermore, bioaccumulation of microplastics in the tissues of aquatic organisms can have adverse effects on the aquatic ecosystem, with potential transmission of microplastics to humans and birds. Changing individual behaviours and governmental actions, such as implementing bans, taxes, or pricing on plastic carrier bags, has significantly reduced plastic consumption to 8-85% in various countries worldwide. The microplastic minimisation approach follows an upside-down pyramid, starting with prevention, followed by reducing, reusing, recycling, recovering, and ending with disposal as the least preferable option.

Investigation of autism-related transcription factors underlying sex differences in the effects of bisphenol A on transcriptome profiles and synaptogenesis in the offspring hippocampus

BACKGROUND

Bisphenol A (BPA) has been linked to susceptibility to autism spectrum disorder (ASD). Our recent studies have shown that prenatal BPA exposure disrupted ASD-related gene expression in the hippocampus, neurological functions, and behaviors associated with ASD in a sex-specific pattern. However, the molecular mechanisms underlying the effects of BPA are still unclear.

METHODS

Transcriptome data mining and molecular docking analyses were performed to identify ASD-related transcription factors (TFs) and their target genes underlying the sex-specific effects of prenatal BPA exposure. Gene ontology analysis was conducted to predict biological functions associated with these genes. The expression levels of ASD-related TFs and targets in the hippocampus of rat pups prenatally exposed to BPA were measured using qRT-PCR analysis. The role of the androgen receptor (AR) in BPA-mediated regulation of ASD candidate genes was investigated using a human neuronal cell line stably transfected with AR-expression or control plasmid. Synaptogenesis, which is a function associated with genes transcriptionally regulated by ASD-related TFs, was assessed using primary hippocampal neurons isolated from male and female rat pups prenatally exposed to BPA.

RESULTS

We found that there was a sex difference in ASD-related TFs underlying the effects of prenatal BPA exposure on the transcriptome profiles of the offspring hippocampus. In addition to the known BPA targets AR and ESR1, BPA could directly interact with novel targets (i.e., KDM5B, SMAD4, and TCF7L2). The targets of these TFs were also associated with ASD. Prenatal BPA exposure disrupted the expression of ASD-related TFs and targets in the offspring hippocampus in a sex-dependent manner. Moreover, AR was involved in the BPA-mediated dysregulation of AUTS2, KMT2C, and SMARCC2. Prenatal BPA exposure altered synaptogenesis by increasing synaptic protein levels in males but not in females, but the number of excitatory synapses was increased in female primary neurons only.

CONCLUSIONS

Our findings suggest that AR and other ASD-related TFs are involved in sex differences in the effects of prenatal BPA exposure on transcriptome profiles and synaptogenesis in the offspring hippocampus. These TFs may play an essential role in an increased ASD susceptibility associated with endocrine-disrupting chemicals, particularly BPA, and the male bias of ASD.

In Vitro Effects of Bisphenol Analogs on Immune Cells Activation and Th Differentiation

AIMS

Investigate the immunomodulatory effects of bisphenols in the THP-1 cell line and peripheral blood mononuclear cells in response to lipopolysaccharide (LPS) activation or to phorbol 12-myristate 13-acetate (PMA) and ionomycin.

BACKGROUND

We have previously demonstrated the usefulness of the evaluation of RACK1 expression as a link between endocrine disrupting activity and the immunotoxic effect of xenobiotics. We demonstrated that while BPA and BPAF reduced RACK1 expression, BPS was able to increase it.

OBJECTIVE

Bisphenol A (BPA) is one of the most commonly used chemicals in the manufacturing of polycarbonate plastics and plastic consumer products. Its endocrine disrupting (ED) potential and changes in European regulations have led to replacing BPA in many uses with structurally similar chemicals, like bisphenol AF (BPAF) and bisphenol S (BPS). However, emerging data indicated that bisphenol analogues may not be safer than BPA both in toxic effects and ED potential.

METHODS

THP-1 cell line and peripheral blood mononuclear cells were activated with lipopolysaccharide (LPS) or with phorbol 12-myristate 13-acetate (PMA) and ionomycin.

RESULTS

BPA and BPAF decreased LPS-induced expression of surface markers and the release of pro-inflammatory cytokines, while BPS increased LPS-induced expression of CD86 and cytokines. BPA, BPAF, and BPS affected PMA/ionomycin-induced T helper differentiation and cytokine release with gender-related alterations in some parameters investigated.

CONCLUSION

Data confirm that bisphenols can modulate immune cell differentiation and activation, further supporting their immunotoxic effects.

Acupuncture Ameliorated Behavioral Abnormalities in the Autism Rat Model via Pathways for Hippocampal Serotonin

Purpose

Acupuncture can improve symptoms of autism spectrum disorder (ASD), but the potential mechanisms remain undefined. So, we aimed to explore the behavioral improvement of autism rat model after acupuncture and to describe the potential molecular mechanism underlying these changes.

Patients and Methods

Wistar rats were intraperitoneally injected with VPA 12.5 days after conception, and their offspring were considered as good models of autism. Experimental rats were divided into three groups (wild-type (WT), n = 10; VPA, n = 10; and VPA_acupuncture, n = 10). VPA_acupuncture group rat received 4 weeks of acupuncture treatment (Shéntíng (GV24), and Bilateral Běnshén (GB13)) on the 23rd day after birth. All rats were subjected to behavioral tests, including social interaction, open field, and Morris water maze tests. Afterwards, hippocampal tissues (left side) were removed and subjected to RNA sequencing (RNA-seq) analysis; ELISA was also used to detect the associated serotonin levels in the hippocampus.

Results

Behavioral tests showed that acupuncture treatment improved spontaneous activity, aberrant social interaction, and alleviated impaired learning and memory in the VPA-induced rat model. Differentially expressed genes (DGEs) analysis showed 142 significantly differentially expressed genes between WT and VPA groups, and 282 between VPA and VPA_acupuncture rats. Htr2c and Htr1a, 5-HT receptor genes, were up-regulated in the VPA group compared with WT group. Additionally, Tph1, a rate-limiting enzyme gene of 5-HT synthesis, was up-regulated after acupuncture. These genes were confirmed to have the same trend of expression obtained by RT-qPCR and RNA seq. Furthermore, the concentration of serotonin in the hippocampus in the VPA group was significantly lower than the WT and VPA_acupuncture groups.

Conclusion

Acupuncture improved abnormal behavioral symptoms in the VPA-induced rat model. Further experiments showed that the improvement of the serotonin system may be one of the main regulatory mechanisms of acupuncture for treating ASD.

Length biases in single-cell RNA sequencing of pre-mRNA

Single-cell RNA sequencing data can be modeled using Markov chains to yield genome-wide insights into transcriptional physics. However, quantitative inference with such data requires careful assessment of noise sources. We find that long pre-mRNA transcripts are over-represented in sequencing data. To explain this trend, we propose a length-based model of capture bias, which may produce false-positive observations. We solve this model and use it to find concordant parameter trends as well as systematic, mechanistically interpretable technical and biological differences in paired data sets.

Impact of a bisphenol A, F, and S mixture and maternal care on the brain transcriptome of rat dams and pups

Products containing BPA structural analog replacements have increased in response to growing public concern over adverse effects of BPA. Although humans are regularly exposed to a mixture of bisphenols, few studies have examined effects of prenatal exposure to BPA alternatives or bisphenol mixtures. In the present study, we investigate the effect of exposure to an environmentally-relevant, low-dose (150 ug/kg body weight per day) mixture of BPA, BPS, and BPF during gestation on the brain transcriptome in Long-Evans pups and dams using Tag RNA-sequencing. We also examined the association between dam licking and grooming, which also has enduring effects on pup neural development, and the transcriptomes. Associations between licking and grooming and the transcriptome were region-specific, with the hypothalamus having the greatest number of differentially expressed genes associated with licking and grooming in both dams and pups. Prenatal bisphenol exposure also had region-specific effects on gene expression and pup gene expression was affected more robustly than dam gene expression. In dams, the prelimbic cortex had the greatest number of differentially expressed genes associated with prenatal bisphenol exposure. Prenatal bisphenol exposure changed the expression of over 2000 genes in pups, with the majority being from the pup amygdala. We used Gene Set Enrichment Analysis (GSEA) to asses enrichment of gene ontology biological processes for each region. Top GSEA terms were diverse and varied by brain region and included processes known to have strong associations with steroid hormone regulation, cilium-related terms, metabolic/biosynthetic process terms, and immune terms. Finally, hypothesis-driven analysis of genes related to estrogen response, parental behavior, and epigenetic regulation of gene expression revealed region-specific expression associated with licking and grooming and bisphenol exposure that were distinct in dams and pups. These data highlight the effects of bisphenols on multiple physiological process that are highly dependent on timing of exposure (prenatal vs. adulthood) and brain region, and reiterate the contributions of multiple environmental and experiential factors in shaping the brain.

Sex-specific Effects of Endocrine-disrupting Chemicals on Brain Monoamines and Cognitive Behavior

The period of brain sexual differentiation is characterized by the development of hormone-sensitive neural circuits that govern the subsequent presentation of sexually dimorphic behavior in adulthood. Perturbations of hormones by endocrine-disrupting chemicals (EDCs) during this developmental period interfere with an organism's endocrine function and can disrupt the normative organization of male- or female-typical neural circuitry. This is well characterized for reproductive and social behaviors and their underlying circuitry in the hypothalamus and other limbic regions of the brain; however, cognitive behaviors are also sexually dimorphic, with their underlying neural circuitry potentially vulnerable to EDC exposure during critical periods of brain development. This review provides recent evidence for sex-specific changes to the brain's monoaminergic systems (dopamine, serotonin, norepinephrine) after developmental EDC exposure and relates these outcomes to sex differences in cognition such as affective, attentional, and learning/memory behaviors.

A more than four-fold sex-specific difference of autism spectrum disorders and the possible contribution of pesticide usage in China 1990-2030

Autism spectrum disorders (ASDs) are prevalent in children and adolescents and disproportionately affect males, and the main contributing factors underlying male vulnerability remain widely unknown. Pesticide use is widely reported to be associated with ASD risk, and the cases of pesticide poisoning incidence in rural areas are remarkably higher than those in the urban areas while the prevalence of ASDs in rural areas was higher than that in urban areas and the rate of male pesticide poisoning was significantly higher than female. Thus, pesticide usage may be an important contributing factor for causing sex-specific differences of ASD incidence. ASD burden was analyzed by using the data of ASD number, ASD rate (ASD cases per 100,000 persons) and disability-adjusted life years (DALYs) from 1990 to 2019. The changes from 1990 to 2030 were predicted using autoregressive integrated moving average (ARIMA) in time series forecasting based on the small values of Akaike information criterion and Bayesian information criterion. Finally, the relationship between ASD rate and pesticide usage risk index (PURI) was analyzed via Pearson's correlation coefficient. ASD number, ASD rate and DALYs will be reduced by 45.5% ± 8.2% (t = 9.100 and p = 0.0119), 56.6% ± 10.2% (t = 9.111 and p = 0.0118), and 44.9% ± 7.0% (t = 20.90 and p = 0.0023) from 1990 to 2030 in China. PURI has a strong relationship with ASD rate (rho = 0.953 to 0.988 and p < 0.0001). Pesticide poisoning incidence in males is up to 2-fold higher than that in females. ASD number and DALYs in males are 4-fold higher than those in females. Furthermore, there is growing evidence supporting that males are more susceptible than females to pesticides with sex differences in neurotoxicogenetics. Therefore, pesticide poisoning may be a contributing factor for causing the sex differences of ASD. Much work still needs to be done to confirm that.

Sex differences in cognition following variations in endocrine status

Spatial memory, mediated primarily by the hippocampus, is responsible for orientation in space and retrieval of information regarding location of objects and places in an animal's environment. Since the hippocampus is dense with steroid hormone receptors and is capable of robust neuroplasticity, it is not surprising that changes in spatial memory performance occur following a variety of endocrine alterations. Here, we review cognitive changes in both spatial and nonspatial memory tasks following manipulations of the hypothalamic-pituitary-adrenal and gonadal axes and after exposure to endocrine disruptors in rodents. Chronic stress impairs male performance on numerous behavioral cognitive tasks and enhances or does not impact female cognitive function. Sex-dependent changes in cognition following stress are influenced by both organizational and activational effects of estrogen and vary depending on the developmental age of the stress exposure, but responses to gonadal hormones in adulthood are more similar than different in the sexes. Also discussed are possible underlying neural mechanisms for these steroid hormone-dependent, cognitive effects. Bisphenol A (BPA), an endocrine disruptor, given at low levels during adolescent development, impairs spatial memory in adolescent male and female rats and object recognition memory in adulthood. BPA's negative effects on memory may be mediated through alterations in dendritic spine density in areas that mediate these cognitive tasks. In summary, this review discusses the evidence that endocrine status of an animal (presence or absence of stress hormones, gonadal hormones, or endocrine disruptors) impacts cognitive function and, at times, in a sex-specific manner.

LINE-1 and Alu methylation signatures in autism spectrum disorder and their associations with the expression of autism-related genes

Long interspersed nucleotide element-1 (LINE-1) and Alu elements are retrotransposons whose abilities cause abnormal gene expression and genomic instability. Several studies have focused on DNA methylation profiling of gene regions, but the locus-specific methylation of LINE-1 and Alu elements has not been identified in autism spectrum disorder (ASD). Here we interrogated locus- and family-specific methylation profiles of LINE-1 and Alu elements in ASD whole blood using publicly-available Illumina Infinium 450 K methylation datasets from heterogeneous ASD and ASD variants (Chromodomain Helicase DNA-binding 8 (CHD8) and 16p11.2del). Total DNA methylation of repetitive elements were notably hypomethylated exclusively in ASD with CHD8 variants. Methylation alteration in a family-specific manner including L1P, L1H, HAL, AluJ, and AluS families were observed in the heterogeneous ASD and ASD with CHD8 variants. Moreover, LINE-1 and Alu methylation within target genes is inversely related to the expression level in each ASD variant. The DNA methylation signatures of the LINE-1 and Alu elements in ASD whole blood, as well as their associations with the expression of ASD-related genes, have been identified. If confirmed in future larger studies, these findings may contribute to the identification of epigenomic biomarkers of ASD.

New Insights into Prenatal NO2 Exposure and Behavioral Abnormalities in Male Offspring: Disturbed Serotonin Metabolism and Delayed Oligodendrocyte Development

Epidemiological studies show that prenatal exposure to nitrogen dioxide (NO₂) might cause behavioral abnormalities in childhood. However, toxicological mechanisms for such effects remain unclear, and it is still difficult to define adverse outcome pathways linking exposures to behavioral phenotypes. In this study, by exposing pregnant mice to NO₂ (2.5 ppm, 5 h/day) throughout gestation, we provided the first experimental evidence that prenatal NO₂ exposure did cause anxiety- and depression-like behaviors in weaning male offspring but not females. Specifically, the behavioral abnormalities were associated with abnormal myelination and the alterations attributed to the delayed oligodendrocyte (OL) development in the fetus and the early stage after birth. The expression of platelet-derived growth factor receptor α (Pdgfr-α) and Olig2 significantly decreased in the NO₂ group at E13.5 and E15.5, and the expression of Olig2, adenomatous polyposis coli colon (Cc1), and myelin basic protein (Mbp) was reduced in offspring at PNDs 1, 7, and 21. We performed the targeted metabolomic analysis of neurotransmitters in the placenta and found that prenatal exposure to NO₂ disturbed the metabolism of placental neurotransmitters. Serotonin (5-HT) was transferred from the placenta to the fetus at E10.5, and its accumulation in the fetal forebrain might affect oligodendrocyte progenitor cell (OPC) differentiation and OL maturation and eventually be involved in behavioral abnormalities. Our findings provide new insights into the association between prenatal NO₂ exposure with anxiety- and depression-like behaviors in male offspring.

Elevated exposures to persistent endocrine disrupting compounds impact the sperm methylome in regions associated with autism spectrum disorder

Environmental exposures to endocrine disrupting compounds (EDCs) such as the organochlorines have been linked with various diseases including neurodevelopmental disorders. Autism spectrum disorder (ASD) is a highly complex neurodevelopmental disorder that is considered strongly genetic in origin due to its high heritability. However, the rapidly rising prevalence of ASD suggests that environmental factors may also influence risk for ASD. In the present study, whole genome bisulfite sequencing was used to identify genome-wide differentially methylated regions (DMRs) in a total of 52 sperm samples from a cohort of men from the Faroe Islands (Denmark) who were equally divided into high and low exposure groups based on their serum levels of the long-lived organochlorine 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE), a primary breakdown product of the now banned insecticide dichlorodiphenyltrichloroethane (DDT). Aside from being considered a genetic isolate, inhabitants of the Faroe Islands have a native diet that potentially exposes them to a wide range of seafood neurotoxicants in the form of persistent organic pollutants (POPs). The DMRs were mapped to the human genome using Bismark, a 3-letter aligner used for methyl-seq analyses. Gene ontology, functional, and pathway analyses of the DMR-associated genes showed significant enrichment for genes involved in neurological functions and neurodevelopmental processes frequently impacted by ASD. Notably, these genes also significantly overlap with autism risk genes as well as those previously identified in sperm from fathers of children with ASD in comparison to that of fathers of neurotypical children. These results collectively suggest a possible mechanism involving altered methylation of a significant number of neurologically relevant ASD risk genes for introducing epigenetic changes associated with environmental exposures into the sperm methylome. Such changes may provide the potential for transgenerational inheritance of ASD as well as other disorders.

Pax6 loss alters the morphological and electrophysiological development of mouse prethalamic neurons

Pax6 is a well-known regulator of early neuroepithelial progenitor development. Its constitutive loss has a particularly strong effect on the developing prethalamus, causing it to become extremely hypoplastic. To overcome this difficulty in studying the long-term consequences of Pax6 loss for prethalamic development, we used conditional mutagenesis to delete Pax6 at the onset of neurogenesis and studied the developmental potential of the mutant prethalamic neurons in vitro. We found that Pax6 loss affected their rates of neurite elongation, the location and length of their axon initial segments, and their electrophysiological properties. Our results broaden our understanding of the long-term consequences of Pax6 deletion in the developing mouse forebrain, suggesting that it can have cell-autonomous effects on the structural and functional development of some neurons.

Summary: Pax6 impacts neurite extension, axon initial segment properties and the ability to fire normal action potentials in maturing neurons, revealing actions extending beyond those previously characterised in progenitors.

In utero exposure to endocrine disruptors and developmental neurotoxicity: Implications for behavioural and neurological disorders in adult life

Endocrine disrupting chemicals (EDCs) are a class of environmental toxicants that interfere with the endocrine system, resulting in developmental malformations, reproductive disorders, and alterations to immune and nervous system function. The emergence of screening studies identifying these chemicals in fetal developmental matrices such as maternal blood, placenta and amniotic fluid has steered research focus towards elucidation of in utero effects of exposure to these chemicals, as their capacity to cross the placenta and reach the fetus was established. The presence of EDCs, a majority of which are estrogen mimics, in the fetal environment during early development could potentially affect neurodevelopment, with implications for behavioural and neurological disorders in adult life. This review summarizes studies in animal models and human cohorts that aim to elucidate mechanisms of action of EDCs in the context of neurodevelopment and disease risk in adult life. This is a significant area of study as early brain development is heavily mediated by estrogen and could be particularly sensitive to EDC exposure. A network analysis presented using genes summarized in this review, further show a significant association with disorders such as major depressive disorder, alcoholic disorder, psychotic disorders and autism spectrum disorder. Functional outcomes such as alterations in memory, behaviour, cognition, learning memory, feeding behaviour and regulation of ion transport are also highlighted. Interactions between genes, receptors and signaling pathways like NMDA glutamate receptor activity, 5-hydroxytryptamine receptor activity, Ras-activated Ca₂⁺ influx and Grin2A interactions, provide further potential mechanisms of action of EDCs in mediating brain function. Taken together with the growing pool of human and animal studies, this review summarizes current status of EDC neurotoxicity research, limitations and future directions of study for researchers.

Prenatal Bisphenol A Exposure and Early Childhood Behavior and Cognitive Function: A Chinese Birth Cohort Study

INTRODUCTION

Biomonitoring of bisphenol A (BPA) in human blood is still scarce, although already noticeable. We aimed to examine the associations between prenatal serum BPA concentrations and behavior and cognitive function in preschool children.

METHODS

A total of 1,782 mother-child pairs with complete demographic information, blood samples, and psychological measurements were included from the China-Anhui Birth Cohort (C-ABCS). We detected serum BPA concentrations and assessed children's neurodevelopment using a set of psychometric scales.

RESULTS

The median prenatal maternal serum BPA concentration was 0.23 (P25, P75: 0.07, 0.52) ng/mL, with a detection frequency of 85.19%. Compared with the girls with the lowest concentrations, those with highest BPA concentrations had increased risks of inhibitory self-control impairment [relative risk (RR) = 3.66, 95% confidence interval (CI): 1.53, 7.58], emergent metacognition impairment (RR = 1.70, 95% CI: 1.07, 2.78), conduct problem (RR = 1.68, 95% CI: 1.12, 2.39), peer relationship problem (RR = 2.57, 95% CI: 1.33, 4.47), higher total difficulties score (RR = 1.76, 95% CI: 1.12, 2.67), and higher impact factor score (RR = 1.52, 95% CI: 1.11, 2.05), while the boys with the highest prenatal BPA concentrations had an increased risk of conduct problem compared with those with the lowest concentrations (RR = 1.59, 95% CI: 1.09, 2.24) (P-interaction = 0.011). After stratification by age, high prenatal BPA concentrations were associated with increased ADHD (RR = 4.44, 95% CI: 1.54, 10.85) among children aged 3 years, not among children aged 4 years.

CONCLUSION

Our study revealed the sex-specific and age-specific impacts of prenatal BPA exposure on preschool children's cognitive and behavioral development.

Autism-Related Transcription Factors Underlying the Sex-Specific Effects of Prenatal Bisphenol A Exposure on Transcriptome-Interactome Profiles in the Offspring Prefrontal Cortex

Bisphenol A (BPA) is an environmental risk factor for autism spectrum disorder (ASD). BPA exposure dysregulates ASD-related genes in the hippocampus and neurological functions of offspring. However, whether prenatal BPA exposure has an impact on genes in the prefrontal cortex, another brain region highly implicated in ASD, and through what mechanisms have not been investigated. Here, we demonstrated that prenatal BPA exposure disrupts the transcriptome-interactome profiles of the prefrontal cortex of neonatal rats. Interestingly, the list of BPA-responsive genes was significantly enriched with known ASD candidate genes, as well as genes that were dysregulated in the postmortem brain tissues of ASD cases from multiple independent studies. Moreover, several differentially expressed genes in the offspring's prefrontal cortex were the targets of ASD-related transcription factors, including AR, ESR1, and RORA. The hypergeometric distribution analysis revealed that BPA may regulate the expression of such genes through these transcription factors in a sex-dependent manner. The molecular docking analysis of BPA and ASD-related transcription factors revealed novel potential targets of BPA, including RORA, SOX5, TCF4, and YY1. Our findings indicated that prenatal BPA exposure disrupts ASD-related genes in the offspring's prefrontal cortex and may increase the risk of ASD through sex-dependent molecular mechanisms, which should be investigated further.

Alteration of Extracellular Matrix Components in the Anterior Pituitary Gland of Neonatal Rats Induced by a Maternal Bisphenol A Diet during Pregnancy

The extracellular matrix (ECM) plays crucial roles in the anterior pituitary gland via the mechanism of cell-ECM interaction. Since bisphenol A (BPA), a well-known endocrine disruptor, can cross through the placenta from mother to fetus and bind with estrogen receptors, cell populations in the neonatal anterior pituitary gland could be the target cells affected by this chemical. The present study treated maternal rats with 5000 µg/kg body weight of BPA daily throughout the pregnancy period and then investigated the changes in ECM-producing cells, i.e., pericytes and folliculostellate (FS) cells, including their ECM production in the neonatal anterior pituitary at Day 1. We found that pericytes and their collagen synthesis reduced, consistent with the increase in the number of FS cells that expressed several ECM regulators-matrix metalloproteinase (MMP) 9 and the tissue inhibitors of metalloproteinase (TIMP) family. The relative MMP9/TIMP1 ratio was extremely high, indicating that the control of ECM homeostasis was unbalanced. Moreover, transmission electron microscopy showed the unorganized cell cluster in the BPA-treated group. This study revealed that although the mother received BPA at the "no observed adverse effect" level, alterations in ECM-producing cells as well as collagen and the related ECM balancing genes occurred in the neonatal anterior pituitary gland.

Behavioral changes and hyperglycemia in NODEF mice following bisphenol S exposure are affected by diets

Bisphenol S (BPS), an analogue of the controversial bisphenol A (BPA) that is found in epoxy resins and plastics, is a potential endocrine-disrupting chemical that can mimic endogenous hormone signaling. However, little is known about the behavioral or immunologic effects of BPS. The purpose of this study was to examine the impact of diets in BPS-treated mice in relation to hyperglycemia, development of type 1 diabetes, immunomodulation, and behavioral changes. Adult male and female nonobese diabetic excluded flora (NODEF) mice were exposed to environmentally relevant doses of BPS (VH, 30, or 300 μg/kg BW) and fed either a soy-based diet, a phytoestrogen-free diet, or a Western diet. NODEF male mice fed a soy-based diet exhibited a decreased curiosity/desire to explore, and possibly increased anxiety-like behavior and decreased short-term memory when exposed to BPS (300 μg/kg BW). In addition, these mice had significant increases in non-fasting blood glucose levels along with increased insulin sensitivity, impaired glucose tolerance, resistance to fasting and proinflammation. Although BPS had little effect on the glucose parameters in NODEF male mice fed a Western diet, there were decreases in %CD24⁺CD5⁺ and %B220⁺CD40L^-cell populations and increases in distance traveled during the novel object test, suggesting hyperactivity. NODEF females fed a phytoestrogen-free diet exhibited slight decreases in time spent immobile during the tail suspension test in both the 30 and 300 μg/kg BW dose groups along with increases in %CD4⁺CD8⁺ and %Mac3⁺CD45R⁺ cell populations, signifying increased hyperactivity and anxiety-like behavior. In conclusion, BPS-exposed NODEF mice exhibited sex and diet-related changes in hyperglycemia, behaviors and immune endpoints.