Bisphenol a affects neurodevelopmental gene expression, cognitive function, and neuromuscular synaptic morphology in Drosophila melanogaster

Bisphenol A (BPA) and neurological disorders: An overview

The human body is commonly exposed to bisphenol A (BPA), which is widely used in consumer and industrial products. BPA is an endocrine-disrupting chemical that has adverse effects on human health. In particular, many studies have shown that BPA can cause various neurological disorders by affecting brain development and neural function during prenatal, infancy, childhood, and adulthood exposure. In this review, we discussed the correlation between BPA and neurological disorders based on molecular cell biology, neurophysiology, and behavioral studies of the effects of BPA on brain development and function. Recent studies, both animal and epidemiological, strongly indicate that BPA significantly impacts brain development and function. It hinders neural processes, such as proliferation, migration, and differentiation during development, affecting synaptic formation and activity. As a result, BPA is implicated in neurodevelopmental and neuropsychiatric disorders like autism spectrum disorder (ASD), attention-deficit hyperactivity disorder (ADHD), and schizophrenia.

Bisphenol F affects neurodevelopmental gene expression, mushroom body development, and behavior in Drosophila melanogaster

Bisphenol F (BPF) is a potential neurotoxicant used as a replacement for bisphenol A (BPA) in polycarbonate plastics and epoxy resins. We investigated the neurodevelopmental impacts of BPF exposure using Drosophila melanogaster as a model. Our transcriptomic analysis indicated that developmental exposure to BPF caused the downregulation of neurodevelopmentally relevant genes, including those associated with synapse formation and neuronal projection. To investigate the functional outcome of BPF exposure, we evaluated neurodevelopmental impacts across two genetic strains of Drosophila- w1118 (control) and the Fragile X Syndrome (FXS) model-by examining both behavioral and neuronal phenotypes. We found that BPF exposure in w1118 Drosophila caused hypoactive larval locomotor activity, decreased time spent grooming by adults, reduced courtship activity, and increased the severity but not frequency of β-lobe midline crossing defects by axons in the mushroom body. In contrast, although BPF reduced peristaltic contractions in FXS larvae, it had no impact on other larval locomotor phenotypes, grooming activity, or courtship activity. Strikingly, BPF exposure reduced both the severity and frequency of β-lobe midline crossing defects in the mushroom body of FXS flies, a phenotype previously observed in FXS flies exposed to BPA. This data indicates that BPF can affect neurodevelopment and its impacts vary depending on genetic background. Further, BPF may elicit a gene-environment interaction with Drosophila fragile X messenger ribonucleoprotein 1 (dFmr1)-the ortholog of human FMR1, which causes fragile X syndrome and is the most common monogenetic cause of intellectual disability and autism spectrum disorder.

Bisphenol F and Bisphenol S exposure during development reduce neuronal ganglia integrity and change behavioral profile of Drosophila melanogaster larvae

The behavior and neuronal ganglia integrity of Drosophila melanogaster larvae exposed to Bisphenol F (BPF) and Bisphenol S (BPS) (0.25, 0.5 and 1 mM) was evaluated. Larvae exposed to BPF and BPS (0.5 and 1 mM) showed hyperactivity, reduced decision-making capacity and were not responsive to touch (no sensitivity to physical stimuli). There was also a reduction in the tunneling capacity induced by 1 mM of BPF and BPS (innate behaviors for survival). Behaviors resulting from changes in neuronal functioning, thermotaxis and phototaxis showed that BPS was more harmful compared to BPF. Furthermore, the concentration of 1 mM BPS generated greater damage to neuronal ganglia when compared to BPF. This difference may be related to the LC50 of the 10.04 mM BPS and 15.07 mM BPF. However, these behavioral changes presented by the larvae here are characteristic of those presented in neurodevelopmental disorders. Our findings are novel and refute the possibility that BPF and BPS are safer alternatives.

Effect of bisphenol A on the neurological system: a review update

Bisphenol A (BPA) is an endocrine-disrupting chemical (EDC) and one of the most produced synthetic compounds worldwide. BPA can be found in epoxy resins and polycarbonate plastics, which are frequently used in food storage and baby bottles. However, BPA can bind mainly to estrogen receptors, interfering with various neurologic functions, its use is a topic of significant concern. Nonetheless, the neurotoxicity of BPA has not been fully understood despite numerous investigations on its disruptive effects. Therefore, this review aims to highlight the most recent studies on the implications of BPA on the neurologic system. Our findings suggest that BPA exposure impairs various structural and molecular brain changes, promoting oxidative stress, changing expression levels of several crucial genes and proteins, destructive effects on neurotransmitters, excitotoxicity and neuroinflammation, damaged blood-brain barrier function, neuronal damage, apoptosis effects, disruption of intracellular Ca2+ homeostasis, increase in reactive oxygen species, promoted apoptosis and intracellular lactate dehydrogenase release, a decrease of axon length, microglial DNA damage, astrogliosis, and significantly reduced myelination. Moreover, BPA exposure increases the risk of developing neurologic diseases, including neurovascular (e.g. stroke) and neurodegenerative (e.g. Alzheimer's and Parkinson's) diseases. Furthermore, epidemiological studies showed that the adverse effects of BPA on neurodevelopment in children contributed to the emergence of serious neurological diseases like attention-deficit/hyperactivity disorder (ADHD), autism spectrum disorder (ASD), depression, emotional problems, anxiety, and cognitive disorders. In summary, BPA exposure compromises human health, promoting the development and progression of neurologic disorders. More research is required to fully understand how BPA-induced neurotoxicity affects human health.

Fluorene-9-bisphenol affects the terminal differentiation of mouse embryonic bodies

Fluorene-9-bisphenol (BHPF) has recently attracted interest as it is increasingly used in industrial settings as a substitute for Bisphenol A (BPA). However, the effects of BHPF exposure on embryonic stem cell (ESC) self-renewal, pluripotency, and differentiation remain poorly understood. This study investigates the impacts of BHPF on mouse embryonic stem cells (mESCs) and embryonic bodies (EBs). Our results reveal that BHPF exposure leads to a morphological shift in mESCs, reducing the percentage of dome-shaped colonies and indicating loss of self-renewal and pluripotency. BHPF exposure also appeared to affect the early stages of EB formation and their growth dynamics, with a reduction in EB numbers and an increase in their size. Subsequent gene expression analysis revealed that BHPF exposure led to increased expression of the inflammatory gene Il6, indicating a potential stress response. Furthermore, BHPF affected the terminal differentiation pathway, modulating the expression of 16 genes associated with distinct cell types, including lymphatic endothelium, keratinocyte epithelium, pancreatic beta cells, macrophages, monocytes, T-cells, neurons, retinal ganglion cells, nephrons proximal tubule cells, and cardiomyocytes. These findings offer insights into the impact of BHPF on ESC biology and suggest potential implications for developmental and neurodegenerative disorders. Future work should focus on elucidating the underlying mechanisms of BHPF-mediated effects on stem cell function. This may offer new perspectives for understanding the health impacts of environmental exposure to BHPF.

Genotoxic action of bifenthrin nanoparticles and its effect on the development, productivity, and behavior of Drosophila melanogaster

Rapid development of nanotechnology, particularly nanoparticles of pesticides, has facilitated the transformation of traditional agriculture. However, testing their effectiveness is essential for avoiding any environmental or adverse human health risk attributed to nanoparticle-based formulations, especially insecticides. Recently, organic nanoparticles of bifenthrin, a pyrethroid insecticide, were successfully synthesized by laser ablation of solids in liquid technique, with the most probable size of 5 nm. The aim of the present study was to examine the effects of acute exposure to bifenthrin (BIF) or bifenthrin nanoparticles (BIFNP) on larval-adult viability, developmental time, olfactory capacity, longevity, productivity defined as the number of eggs per couple, and genotoxicity in Drosophila melanogaster. Data demonstrated that BIFNP produced a marked delay in developmental time, significant reduction in viability and olfactory ability compared to BIF. No marked differences were detected between BIF and BIFNP on longevity and productivity. Genotoxicity findings indicated that only BIF, at longer exposure duration increased genetic damage.

Developmental neurotoxic effects of bisphenol A and its derivatives in Drosophila melanogaster

As a result of the ban on bisphenol A (BPA), a hormone disruptor with developmental neurotoxicity, several BPA derivatives (BPs) have been widely used in industrial production. However, there are no effective methods for assessing the neurodevelopmental toxic effects of BPs. To address this, a Drosophila exposure model was established, and W¹¹¹⁸ was reared in food containing these BPs. Results showed that each BPs displayed different semi-lethal doses ranging from 1.76 to 19.43 mM. Exposure to BPs delayed larval development and affected axonal growth, resulting in the abnormal crossing of the midline of axons in the β lobules of mushroom bodies, but the damage caused by BPE and BPF was relatively minor. BPC, BPAF, and BPAP have the most significant effects on locomotor behavior, whereas BPC exhibited the most affected social interactions. Furthermore, exposure to high-dose BPA, BPC, BPS, BPAF, and BPAP also significantly increased the expression of Drosophila estrogen-related receptors. These demonstrated that different kinds of BPs had different levels of neurodevelopmental toxicity, and the severity was BPZ > BPC and BPAF > BPB > BPS > BPAP ≈ BPAl ≈ BPF > BPE. Therefore, BPZ, BPC, BPS, BPAF, and BPAP should be evaluated as potential alternatives to BPA.

Evaluating Learning and Memory in Drosophila melanogaster to Study the Neurodevelopmental Impacts of Toxicants

Neurodevelopmental disorders are a heterogeneous group of behaviorally defined disorders with both genetic and environmental risk factors. Given that many neurodevelopmental disorders are characterized by impaired learning and/or intellectual abilities, behavioral paradigms that assess cognition in animal models have been effective tools in delineating underlying genetic variants that impact disease pathophysiology. For example, learning and memory paradigms in the common fruit fly Drosophila melanogaster have been successfully used to study risk genes and biological pathways associated with several neurodevelopmental disorders, including fragile X syndrome, autism spectrum disorder, and CHARGE syndrome. While these established Drosophila behavioral paradigms have historically been used to investigate genetic risk factors, they also have many other applications, including use in developmental neurotoxicology studies to determine environmental risk factors for neurodevelopmental disorders. There is, however, a deficit of step-by-step protocols that describe how to apply learning and memory assays in fruit flies to developmental neurotoxicology studies. Here, we describe two quantitative behavioral paradigms for Drosophila-predator-induced oviposition and courtship conditioning-that can be used to measure different forms of learning and memory in the context of a developmental neurotoxicology study. Non-associative learning and memory are measured here by examining female Drosophila oviposition behavior in response to endoparasitoid wasps, while associative learning and memory are measured in males using courtship conditioning. Our protocols outline procedures for oral toxicant exposure of developing fruit flies, culturing of endoparasitoid wasps, measuring Drosophila oviposition activity, and assessing conditioned courtship in order to identify the impact of toxicants on learning and memory in both females and males. As an example, we present the protocols using bisphenol A, a chemical utilized in the synthesis of polycarbonate plastics, to determine its impacts on learning and memory. These protocols are inexpensive and relatively simple to perform, and can be used by labs that are new to Drosophila behavioral research to evaluate how toxicant exposure influences learning and memory in male and female flies. © 2022 Wiley Periodicals LLC. Basic Protocol 1: Preparation of toxicant-containing food and developmental exposure Basic Protocol 2: Predator-induced oviposition assay Support Protocol: Culture of Leptopilina heterotoma Basic Protocol 3: Conditioned courtship assay.

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

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