Bisphenol A exposure induces neurobehavioral deficits and neurodegeneration through induction of oxidative stress and activated caspase-3 expression in zebrafish brain

Prenatal co-exposure to phthalate metabolites and bisphenols among non-syndromic cleft lip and/or palate in offspring

Phthalate metabolites and bisphenols can cause adverse pregnancy outcomes. However, there is no study to evaluate the associations of prenatal exposure to phthalate metabolites and bisphenols with non-syndromic cleft lip and/or palate (NSCL/P) risk in offspring. A population-based case-control study was conducted in a multicenter setting from 2005 to 2021, enrolling 448 pregnant women. Seven phthalate metabolites and six bisphenols were quantified in placenta using liquid chromatography-tandem mass spectrometry. In the logistic regression analysis, high levels of mono-ethyl phthalate, mono-cyclohexyl phthalate, mono-octyl phthalate, bisphenol A, bisphenol AF, bisphenol AP, and fluorene-9-bisphenol were associated with increased NSCL/P risk with odds ratios (95% confidence intervals) of 1.86(1.07,3.25), 6.56(3.47,12.39), 8.49(4.44,16.24), 8.34(4.32,16.08), 3.19(1.81,5.62), 2.78(1.59,4.86), and 5.16(2.82,9.44). The Bayesian kernel machine regression model revealed that co-exposure to phthalate metabolites and bisphenols was associated with increased NSCL/P risk. Similarly, quantile-based g-computation analysis indicated that each quantile increase in mixture concentration was positively related to higher risk for NSCL/P [odds ratio (95% confidence interval) = 2.98(1.97,4.51)]. This study provides novel evidence that prenatal single and co-exposure to phthalate metabolites and bisphenols were associated with increased NSCL/P risk, suggesting that exposure to phthalate metabolites and bisphenols during pregnancy should be minimized to reduce the incidence of NSCL/P in offspring.

Folic acid mitigates the developmental and neurotoxic effects of bisphenol A in zebrafish by inhibiting the oxidative stress/JNK signaling pathway

Bisphenol A (BPA) is a widespread environmental endocrine disruptor (EED) that can cause various environmental and health issues by inducing oxidative stress. The c-Jun N-terminal kinase (JNK) signaling pathway plays a crucial role in oxidative stress-mediated cellular damage. Although folic acid (FA) has demonstrated antioxidant properties, its potential protective effects against BPA-induced developmental and neurotoxicity, as well as the mechanisms involved in the JNK signaling pathway, are still not completely understood. Zebrafish embryos were exposed to different concentrations of BPA ranging from 20 to 40 µM, with or without treatment of 50 µM FA, starting at 6 hours post-fertilization (hpf). Various parameters such as hatchability, survival rate, body length, and heart rate were measured and analyzed. Transcriptome sequencing was conducted to study the changes in gene expression. Oxidative stress markers, including reactive oxygen species (ROS), lipid peroxidation (LPO), hydrogen peroxide (H2O2), and catalase (CAT) activity, were assessed. The expression of proteins related to the mitogen-activated protein kinase (MAPK)/JNK pathway was analyzed using western blot. Neurodevelopmental and apoptotic outcomes were evaluated through behavioral tests, immunofluorescence and RT-qPCR examinations. The study found that exposure to BPA led to a decrease in hatchability, survival, body length, heart rate, total antioxidant capacity and promoted apoptosis in zebrafish larvae. However, supplementation with FA was able to alleviate these negative effects. BPA exposure increased levels of ROS, LPO, and H2O2, while decreasing CAT activity in zebrafish larvae. Treatment with FA effectively reduced BPA-induced oxidative stress and restored antioxidant defense systems. Moreover, KEGG pathway enrichment analysis revealed that the MAPK signaling pathway was the most enriched signaling pathway. Further studies revealed that BPA activated the JNK signaling pathway, while FA suppressed this activation. Additionally, FA significantly improved BPA-induced neurobehavioral deficits and protected against neurocytological alterations. Our findings demonstrate that FA effectively protects against BPA-induced developmental and neurotoxic effects in zebrafish by suppressing oxidative stress and inhibiting the JNK signaling pathway. This study provides new strategies and insights for preventing BPA-induced developmental and neurotoxicity in aquatic organisms.

Ferroptosis involvement in the neurotoxicity of flunitrazepam in zebrafish

In recent years, psychoactive drugs such as benzodiazepines (BZDs) have been frequently detected in water environments, however, there is still limited understanding regarding their potential impact on neurological health and underlying mechanisms. This study evaluated the neurotoxicity of the typical BZD drug flunitrazepam (FLZ, 0.2 and 5 μg/L) in zebrafish embryos and adults, and investigated the relationship between ferroptosis and FLZ-induced neurotoxicity. The results indicated that acute exposure to FLZ significantly inhibited zebrafish embryo hatching and promotes death, induced larval deformities, and led to abnormal neurobehavioral responses in larvae, likely due to ferroptosis induction. Results from a 30-day subacute exposure to FLZ showed that it decreased motor function and induced cognitive impairment in adult zebrafish. Immunofluorescence of brain tissues revealed a reduction in neurons in the telencephalon and an increase in microglia in the mesencephalon of the zebrafish exposed to FLZ. The ultrastructure of brain mitochondria showed serious damage. Besides, FLZ exposure increased iron levels, reduced GSH/GSSG and increased LPO in brain tissue, which is related to the abnormal expression of genes associated with ferroptosis. In the rescue experiments with co-exposure to deferoxamine (DFO), the motor-related parameters and biochemical indexes related to ferroptosis were restored, suggesting that FLZ can induce ferroptosis. The molecular docking results indicated that FLZ had a higher affinity with transferrin. This study elucidates the close relationship between ferroptosis and FLZ-induced neurotoxicity, which is significant for understanding the physiological damage caused by psychoactive substances and assessing environmental risks.

Bisphenol F-induced precocious genesis of aggressive neurobehavioral response is associated with heightened monoamine oxidase activity and neurodegeneration in zebrafish brain

The production and use of plastics and plastics products has increased dramatically in recent decades. Moreover, their unprotected disposal into ambient life sustaining environment poses a significant health risk. Bisphenol F (BPF) an alternative to bisphenol A (BPA) has been extensively employed for making of plastics. Recent reports have documented the neurotoxic potential of BPF through induction of altered neurochemical profile, microglia-astrocyte-mediated neuroinflammation, oxidative stress, transformed neurobehavioral response, cognitive dysfunction, etc. In the present study, our approach was to understand the underlying mechanism of BPF-persuaded genesis of aggressive neurobehavioral response in zebrafish. The basic findings advocated a temporal transformation in native explorative behaviour and progressive induction of aggressive behavioural response in zebrafish following exposure to BPF. Our neurobehavioral findings supported the argument of oxidative stress-mediated neuromorphological transformation in the periventricular grey zone (PGZ) of the zebrafish brain. In line with earlier reports, our findings also showed that heightened monoamine oxidase (MAO) activity and downregulation in tyrosine hydroxylase expression in the zebrafish brain is associated with the precocious genesis of aggressive neurobehavioral response in zebrafish brain. Our findings also shed light on BPF-instigated apoptotic neuronal death as revealed by augmented chromatin condensation and cleaved caspase-3 expression. Further observation showed that the downregulation of NeuN (a marker of post-mitotic mature neuron) expression provided substantial neurotoxicity, leading to neurodegeneration in the PGZ region of the zebrafish brain. These basic findings grossly advocate that BPF acts as a potent neurotoxicant in transmuting native neurobehavioral response through the induction of oxidative stress, heightened MAO activity and neuromorphological transformation in the zebrafish brain.

Bisphenol-F and Bisphenol-S (BPF and BPS) Impair the Stemness of Neural Stem Cells and Neuronal Fate Decision in the Hippocampus Leading to Cognitive Dysfunctions

Neurogenesis occurs throughout life in the hippocampus of the brain, and many environmental toxicants inhibit neural stem cell (NSC) function and neuronal generation. Bisphenol-A (BPA), an endocrine disrupter used for surface coating of plastic products causes injury in the developing and adult brain; thus, many countries have banned its usage in plastic consumer products. BPA analogs/alternatives such as bisphenol-F (BPF) and bisphenol-S (BPS) may also cause neurotoxicity; however, their effects on neurogenesis are still not known. We studied the effects of BPF and BPS exposure from gestational day 6 to postnatal day 21 on neurogenesis. We found that exposure to non-cytotoxic concentrations of BPF and BPS significantly decreased the number/size of neurospheres, BrdU+ (proliferating NSC marker) and MAP-2+ (neuronal marker) cells and GFAP+ astrocytes in the hippocampus NSC culture, suggesting reduced NSC stemness and self-renewal and neuronal differentiation and increased gliogenesis. These analogs also reduced the number of BrdU/Sox-2+, BrdU/Dcx+, and BrdU/NeuN+ co-labeled cells in the hippocampus of the rat brain, suggesting decreased NSC proliferation and impaired maturation of newborn neurons. BPF and BPS treatment increases BrdU/cleaved caspase-3+ cells and Bax-2 and cleaved caspase protein levels, leading to increased apoptosis in hippocampal NSCs. Transmission electron microscopy studies suggest that BPF and BPS also caused degeneration of neuronal myelin sheath, altered mitochondrial morphology, and reduced number of synapses in the hippocampus leading to altered cognitive functions. These results suggest that BPF and BPS exposure decreased the NSC pool, inhibited neurogenesis, induced apoptosis of NSCs, caused myelin degeneration/synapse degeneration, and impaired learning and memory in rats.

Concerted monoamine oxidase activity following exposure to di-2-ethylhexyl phthalate is associated with aggressive neurobehavioral response and neurodegeneration in zebrafish brain

Di-2-ethylhexyl phthalate (DEHP) is the most commonly preferred synthetic organic chemical in plastics and its products for making them ductile, flexible and durable. As DEHP is not chemically bound to the macromolecular polymer of plastics, it can be easily leached out to accumulate in food and environment. Our recent report advocated that exposure to DEHP significantly transformed the innate bottom-dwelling and scototaxis behaviour of zebrafish. Our present study aimed to understand the possible role of DEHP exposure pertaining towards the development of aggressive behaviour and its association with amplified monoamine oxidase activity and neurodegeneration in the zebrafish brain. As heightened monoamine oxidase (MAO) is linked with genesis of aggressive behaviour, our observation also coincides with DEHP-persuaded aggressive neurobehavioral transformation in zebrafish. Our preliminary findings also showed that DEHP epitomized as a prime factor in transforming native explorative behaviour and genesis of aggressive behaviour through oxidative stress induction and changes in the neuromorphology in the periventricular grey zone (PGZ) of the zebrafish brain. With the finding demarcating towards heightened chromatin condensation in the PGZ of zebrafish brain, our further observation by immunohistochemistry showed a profound augmentation in apoptotic cell death marker cleaved caspase 3 (CC3) expression following exposure to DEHP. Our further observation by immunoblotting study also demarcated a temporal augmentation in CC3 and tyrosine hydroxylase expression in the zebrafish brain. Therefore, the gross findings of the present study delineate the idea that chronic exposure to DEHP is associated with MAO-instigated aggressive neurobehavioral transformation and neurodegeneration in the zebrafish brain.

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.

In Vivo Assays for Amyloid-Related Diseases

Amyloid-related diseases, such as Alzheimer's and Parkinson's disease, are devastating conditions caused by the accumulation of abnormal protein aggregates known as amyloid fibrils. While assays involving animal models are essential for understanding the pathogenesis and developing therapies, a wide array of standard analytical techniques exists to enhance our understanding of these disorders. These techniques provide valuable information on the formation and propagation of amyloid fibrils, as well as the pharmacokinetics and pharmacodynamics of candidate drugs. Despite ethical concerns surrounding animal use, animal models remain vital tools in the search for treatments. Regardless of the specific animal model chosen, the analytical methods used are usually standardized. Therefore, the main objective of this review is to categorize and outline the primary analytical methods used in in vivo assays for amyloid-related diseases, highlighting their critical role in furthering our understanding of these disorders and developing effective therapies.

Effects and mechanisms of bisphenols exposure on neurodegenerative diseases risk: A systemic review

Environmental bisphenols (BPs) pose a global threat to human health because of their extensive use as additives in plastic products. BP residues are increasing in various environmental media (i.e., water, soil, and indoor dust) and biological and human samples (i.e., serum and brain). Both epidemiological and animal studies have determined an association between exposure to BPs and an increased risk of neurodegenerative diseases (e.g., Parkinson's disease, Alzheimer's disease, and amyotrophic lateral sclerosis), including cognitive abnormalities and behavioral disturbances. Hence, understanding the biological responses to different BPs is essential for prevention, and treatment. This study provides an overview of the underlying pathogenic molecular mechanisms as a valuable basis for understanding neurodegenerative disease responses to BPs, including accumulation of misfolded proteins, reduction of tyrosine hydroxylase and dopamine, abnormal hormone signaling, neuronal death, oxidative stress, calcium homeostasis, and inflammation. These findings provide new insights into the neurotoxic potential of BPs and ultimately contribute to a comprehensive health risk evaluation.

Enzymatic and transcriptional level changes induced by the co-presence of lead and procymidone in hook snout carp (Opsariichthys bidens)

Understanding the interactions between different environmental pollutants is necessary in ecotoxicology since environmental contaminants never appear as single components but rather in combination with other substances. Heavy metals and pesticides are commonly detected in the environment, but the characterization of their mixture toxicity has been inadequately explored. This research aimed to elucidate the mixture impacts of the heavy metal lead (Pb) and the pesticide procymidone (PCM) on the hook snout carp (Opsariichthys bidens) using an array of biomarkers. The data showed that Pb and PCM possessed almost equivalent acute toxicity to the animals, with 4-days LC50 values of 120.9 and 85.15 mg L-1, respectively. Combinations of Pb and PCM generated acute synergistic effects on O. bidens. The contents of malondialdehyde (MDA), antioxidative (SOD), apoptotic (caspase-9), and detoxifying enzymes glutathione S-transferase (GST) and cytochrome P450 (CYP450) significantly changed after most of the mixture exposures compared with the baseline level and the corresponding individual exposures. This suggests the induction of oxidative stress, cell damage, and detoxification dysfunction. The expressions of eight genes (mn-sod, cu-sod, p53, cas3, erβ1, esr, ap, and klf2α) associated with oxidative stress, cell apoptosis, immune response, and hormonal functions exhibited pronounced changes when challenged with the mixture compared to the individual treatments. This indicates the occurrence of immune dysregulation and endocrine disorder. These findings provide an overall understanding of fish upon the challenge of sublethal toxicity between Pb and PCM and can be adopted to evaluate the complicated toxic mechanisms in aquatic vertebrates when exposed to heavy metal and pesticide mixtures. Additionally, these results might guide environmental regulation tactics to protect the population of aquatic vertebrates in natural ecosystems.

The probiotic SLAB51 as agent to counteract BPA toxicity on zebrafish gut microbiota -liver-brain axis

A plethora of studies have so far described the toxic effects of bisphenol A (BPA) on organism health, highlighting the urgent need to find new strategies not only to reduce the presence of this toxicant but also to counteract its adverse effects. In this context, probiotics emerged as a potential tool since they promote organism welfare. Using a multidisciplinary approach, this study explores the effects of SLAB51 dietary administration to counteract BPA toxicity using zebrafish as a model. Adult males and females were maintained under standard conditions (control group; C), exposed for 28 days via the water to an environmental relevant dose of BPA (10 μg/L; BPA), dietary treated with SLAB51 (109 CFU/g of body weight; P) and co-treated with BPA plus SLAB51 (BPA + P). In the gut, exposure to BPA resulted in altered architecture in both males and females, with females also experiencing an increase of pathogenic bacterial species. Co-administration of BPA + P led to the restoration of normal gut architecture, favored beneficial bacteria colonization, and decreased the abundance of pathogenic species. In the liver, male BPA exposure led to steatosis and glycogen depletion, which was partially mitigated by SLAB51 co-administration. In contrast, in females exposed to BPA, the lack of steatosis along with the greater glycogen depletion, suggested an increase in energy demand as supported by the metabolomic phenotype. The analysis of liver metabolites in BPA + P males revealed increased levels of anserine and reduced levels of glutamine, which could lie behind the counteraction of the brain histopathological damage caused by BPA. In BPA + P females, a reduction of retinoic acid was found in the liver, suggesting an increase in retinoids responsible for BPA detoxification. Overall, these results demonstrate that SLAB51 exerts its beneficial effects on the gut microbiota-brain-liver axis through distinct molecular pathways, effectively mitigating the pleiotropic toxicity of BPA.

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.

Teratogenic and neuro-behavioural toxic effects of bisphenol A (BPA) and B (BPB) on Xenopus laevis development

Bisphenol A (BPA) is a plastic additive with endocrine disruptive activity, classified in 2017 by EU ECHA as substance of very high concern. A correlation between environmental exposure to BPA and congenital defects has been described in humans and in experimental species, including the amphibian Xenopus laevis. Among BPA analogues, bisphenol B (BPB) is used as alternative in different not-EU countries, including US, but seems to share with BPA its endocrine disruptor properties. Aim of the present work is the evaluation of the effects of BPB versus BPA exposure in a X. laevis developmental model. A windowed exposure (R-FETAX method) was applied covering the developmental phylotypic period (teratogenicity window), or the late tailbud stages (neuro-behavioural toxicity window, corresponding to the spontaneous swimming acquisition period). Samples were monitored for lethal effects during the full test period. External morphology evaluation and deglutition functional test were applied in any group. Abnormal tadpoles were also processed for cartilage staining. In groups exposed during neuro-behavioural toxicity window the swimming test was also applied. Lethality and malformations were obtained only in samples exposed during the teratogenicity window; these data were modelled using PROAST software and BPB relative potency resulted about 3 times higher than BPA. The day-by-day evaluation revealed that lethality was correlated to embryonic abnormal development of gills and apoptosis in gill primordia. Teratogenicity was never detected in groups exposed during the neuro-behavioural toxicity window, where some significant neuro-behavioural deficits were detected in tadpoles exposed to the highest tested concentrations of BPA and BPB.

Machine learning identifies phenotypic profile alterations of human dopaminergic neurons exposed to bisphenols and perfluoroalkyls

Parkinson's disease (PD) is the second most common neurodegenerative disease and is characterized by the loss of midbrain dopaminergic neurons. Endocrine disrupting chemicals (EDCs) are active substances that interfere with hormonal signaling. Among EDCs, bisphenols (BPs) and perfluoroalkyls (PFs) are chemicals leached from plastics and other household products, and humans are unavoidably exposed to these xenobiotics. Data from animal studies suggest that EDCs exposure may play a role in PD, but data about the effect of BPs and PFs on human models of the nervous system are lacking. Previous studies demonstrated that machine learning (ML) applied to microscopy data can classify different cell phenotypes based on image features. In this study, the effect of BPs and PFs at different concentrations within the real-life exposure range (0.01, 0.1, 1, and 2 µM) on the phenotypic profile of human stem cell-derived midbrain dopaminergic neurons (mDANs) was analyzed. Cells exposed for 72 h to the xenobiotics were stained with neuronal markers and evaluated using high content microscopy yielding 126 different phenotypic features. Three different ML models (LDA, XGBoost and LightGBM) were trained to classify EDC-treated versus control mDANs. EDC treated mDANs were identified with high accuracies (0.88-0.96). Assessment of the phenotypic feature contribution to the classification showed that EDCs induced a significant increase of alpha-synuclein (αSyn) and tyrosine hydroxylase (TH) staining intensity within the neurons. Moreover, microtubule-associated protein 2 (MAP2) neurite length and branching were significantly diminished in treated neurons. Our study shows that human mDANs are adversely impacted by exposure to EDCs, causing their phenotype to shift and exhibit more characteristics of PD. Importantly, ML-supported high-content imaging can identify concrete but subtle subcellular phenotypic changes that can be easily overlooked by visual inspection alone and that define EDCs effects in mDANs, thus enabling further pathological characterization in the future.

Neurodevelopmental toxicity of bisphenol AF in zebrafish larvae and the protective effects of curcumin

Bisphenol AF (BPAF) is one of the most commonly used alternatives of bisphenol A in the plastics industry. The effects of BPAF on nervous development are unclear. Curcumin (CUR) has been determined to be an anti-inflammatory and antioxidant agent. In this study, the effects of BPAF on neurotoxicity of zebrafish embryos/larvae and whether CUR could reverse effects induced by BPAF were investigated. The results showed that BPAF treatment induced deficits in locomotor behavior, altered the larval brain development, caused aberrant expression of neurogenesis related genes (elavl3, zn5, α-tubulin, syn2a, and gap43), decreased acetylcholinesterase (AChE) activity, and induced oxidative stress, cell apoptosis, and neuroinflammation in zebrafish larvae. CUR addition could block the adverse effects of BPAF on nervous development by attenuated oxidative stress and cell apoptosis induced by BPAF in zebrafish, enhanced the activity of AChE, and increased the expression of genes involved in the pro-inflammatory cytokines (IL-6, IL-1β, TNF-α, and IL-8). The results of this study indicate that BPAF could induce aberrant development on nervous system. However, CUR exerts neuroprotective effects on BPAF-induced neurotoxicity in zebrafish larvae.

Realistic concentrations of Bisphenol-A trigger a neurotoxic response in the brain of zebrafish: Oxidative stress, behavioral impairment, acetylcholinesterase inhibition, and gene expression disruption

Bisphenol A (BPA) is a micro-pollutant found in various environmental matrices at concentrations as low as ng/L. Recent studies have shown that this compound can cause oxidative damage and neurotoxic effects in aquatic organisms. However, there is a lack of research investigating the effects of BPA at environmentally relevant concentrations. Therefore, this study aimed to assess the neurotoxic effects of acute BPA exposure (96 h) at environmentally relevant concentrations (220, 1180, and 1500 ng/L) in adult zebrafish (Danio rerio). The Novel Tank trial was used to evaluate fish swimming behavior, and our results indicate that exposure to 1500 ng/L of BPA reduced the total distance traveled and increased freezing time. Furthermore, the evaluation of biomarkers in the zebrafish brain revealed that BPA exposure led to the production of reactive oxygen species and increased acetylcholinesterase activity. Gene expression analysis also indicated the overexpression of mbp, α1-tubulin, and manf in the zebrafish brain. Based on our findings, we concluded that environmentally relevant concentrations of BPA can cause anxiety-like behavior and neurotoxic effects in adult zebrafish.

Bisphenol A exposure inhibits vascular smooth muscle cell responses: Involvement of proliferation, migration, and invasion

Previous studies have associated bisphenol A (BPA) with malignant tumor formation, infertility, and atherosclerosis in vitro and in vivo. However, the precise mechanisms through which BPA affects the cardiovascular system under normal conditions remain unclear. Therefore, this study investigated the biological mechanisms through which BPA affects the responses of aortic vascular smooth muscle cells (VSMCs). BPA treatment inhibited the proliferative activity of VSMCs and induced G₂/M-phase cell cycle arrest via stimulation of the ATM-CHK2-Cdc25C-p21^WAF1-Cdc2 cascade in VSMCs. Furthermore, BPA treatment upregulated the phosphorylation of mitogen-activated protein kinase (MAPK) pathways such as ERK, JNK, and p38 MAPK in VSMCs. However, the phosphorylation level of AKT was down-regulated by BPA treatment. Additionally, the phosphorylation of ERK, JNK, and p38 MAPK was suppressed when the cells were treated with their respective inhibitors (U0126, SP600125, and SB203580). BPA suppressed MMP-9 activity by reducing the binding activity of AP-1, Sp-1, and NF-κB, thus inhibiting the invasive and migratory ability of VSMCs. These data demonstrate that BPA interferes with the proliferation, migration, and invasion capacities of VSMCs. Therefore, our findings suggest that overexposure to BPA can lead to cardiovascular damage due to dysregulated VSMC responses.

Bisphenol A and its substitutes in the aquatic environment: Occurrence and toxicity assessment

Bisphenol A is classified as a high production volume chemical commonly used in the manufacture of polycarbonate plastics, epoxy resins and thermal paper. The endocrine disrupting properties of this xenobiotic have led to the restriction and prohibition of its use in many consumer products. To date, many chemical compounds with a chemical structure similar to bisphenol A have been used in consumer products as its replacement. The ubiquitous occurrence of bisphenol A and its substitutes in the environment and their endocrine activity as well as adverse effects on aquatic organisms is a global concern, especially because many available literature reports show that many substitutes (e.g. bisphenol AF, bisphenol AP, bisphenol B, bisphenol C, bisphenol F, bisphenol G, bisphenol FL, tetrabromobisphenol A) exert adverse effects on aquatic organisms, similar to, or even stronger than bisphenol A. Therefore, the objective of this paper is to provide a comprehensive overview of the production, sources, occurrence and associated toxicity, as well as the endocrine activity of bisphenol A and its substitutes on aquatic species. The environmental levels and ecotoxicological data presented in this review allowed for a preliminary assessment and prediction of the risk of bisphenol A and its substitutes for aquatic organisms. Furthermore, the data collected in this paper highlight that several compounds applied in bisphenol A-free products are not safe alternatives and regulations regarding their use should be introduced.

Expression of selected nuclear receptors in human epithelial ovarian cell line Caov3 exposed to bisphenol derivatives

Objectives. Bisphenol A (BPA) is an indispensable industrial chemical. However, as a proven endocrine disruptor, it may be associated with several health disturbances, including the reproductive functions impairment and cancer. Due to the restriction of BPA usage, many bisphenol derivatives gradually substitute BPA. However, studies have reported adverse biological effects of BPA analogs, but the specific sites of their action remain largely unknown. Nuclear receptors (NRs) appear to play significant roles in various types of cancer. In addition, they are considered relevant targets of bisphenols. In the present study, we investigated the effects of BPA and its analogs bisphenol S (BPS), bisphenol F (BPF), and bisphenol AF (BPAF) on mRNA expression of selected NRs in the human ovarian epithelial cell line Caov3. The NRs examined included retinoic acid receptor α (RARA), retinoid X receptor α (RXRA), peroxisome proliferator activating receptor β/δ (PPARD), chicken ovalbumin upstream promoter-transcription factor 2 (COUPTFII), and nuclear receptor-related protein 1 (NURR1). Methods. Caov3 cells were treated with the bisphenols at the concentrations of 1 nM, 100 nM, 10 µM and 100 µM. After 24 h and 72 h of incubation, cell viability was determined by the MTS assay, and the selected genes expression was analyzed using RT-qPCR. Results. Bisphenol treatment did not affect Caov3 cell viability, except the significant impairment after exposure to the highest BPAF dose (100 µM). At lower doses, neither bisphenol analog altered the expression of the NRs. However, at the highest concentration (100 µM), BPAF and BPA altered the mRNA levels of PPARD, COUPTFII, and NURR1 in a time- and receptor-specific manner. Conclusions. The effects of bisphenols on the specific NRs in the epithelial ovarian cancer cells were addressed for the first time by the present study. Although generally we did not find that bisphenols may provoke significant alterations in the expression of the selected NRs in Caov3 cells, they may alter mRNA expression of certain NRs at high concentrations.

Genotoxic potential of bisphenol A: A review

Bisphenol A (BPA), as a major component of some plastic products, is abundant environmental pollutant. Due to its ability to bind to several types of estrogen receptors, it can trigger multiple cellular responses, which can contribute to various manifestations at the organism level. The most studied effect of BPA is endocrine disruption, but recently its prooxidative potential has been confirmed. BPA ability to induce oxidative stress through increased ROS production, altered activity of antioxidant enzymes, or accumulation of oxidation products of biomacromolecules is observed in a wide range of organisms - estrogen receptor-positive and -negative. Subsequently, increased intracellular oxidation can lead to DNA damage induction, represented by oxidative damage, single- and double-strand DNA breaks. Importantly, BPA shows several mechanisms of action and can trigger adverse effects on all organisms inhabiting a wide variety of ecosystem types. Therefore, the main aim of this review is to summarize the genotoxic effects of BPA on organisms across all taxa.

Maternal exposure to bisphenol S induces neuropeptide signaling dysfunction and oxidative stress in the brain, and abnormal social behaviors in zebrafish (Danio rerio) offspring

Recent studies show that bisphenol S (BPS) induces multiple adverse effects in exposed organisms; however, the maternal effects of BPS exposure remain poorly understood. Here, we expose adult female zebrafish to environmentally relevant concentrations of BPS (0, 1, 10, 30 μg/L) and 1 μg/L of 17-β-estradiol (E2) as a positive control for 60 days. Females were then paired with BPS-unexposed males and their offspring were raised in control water for 6 months. Maternal exposure to BPS was found to alter social behavior and anxiety response in a dose-specific manner in male offspring. Group preferences and social cohesion were significantly reduced by maternal exposure to 1 and 10 μg/L BPS, respectively. Additionally, maternal exposure to 1 and 30 μg/L BPS and E2 decreased offspring stress responses during the novel tank test. The impaired social behavior was associated with elevated arginine-vasotocin (AVT) level as well as with the altered expression of genes involved in AVT signaling pathway (AVT, avpr1aa) and enzymatic antioxidant genes (cat and Mn-sod) in the brain. Collectively, these results suggest that maternal exposure to environmentally relevant concentrations of BPS alters social behavior in zebrafish offspring, which is likely mediated by oxidative stress and disruption of neuropeptide signaling pathways in the brain.

Critical review of the toxicity mechanisms of bisphenol F in zebrafish (Danio rerio): Knowledge gaps and future directions

Replacement chemicals for bisphenol A, such as bisphenol F (BPF), are detected in aquatic environments worldwide and can potentially exert negative effects on aquatic organisms. We synthesized peer-reviewed literature reporting molecular and physiological responses in zebrafish following exposure to BPF, as BPF is closely related to BPA structure and is a dominant replacement chemical in the marketplace. Global concentrations of BPF in aquatic environments were compiled and compared to physiological and behavioral impacts reported in zebrafish (e.g., developmental abnormalities, oxidative stress, immunotoxicity, endocrine disruption, and neurotoxicity). Using computational approaches, we elucidate BPF-mediated molecular networks and reveal novel biomarkers associated with BPF exposure. Functional classes of proteins including inflammatory cytokines, ATPases, peroxidases, and aromatic l-amino decarboxylases represent novel, underexplored targets of toxicity. Most revealing of this critical review is that few studies report biological responses to BPF at levels present in aquatic environments. Recommendations for future investigations based on knowledge gaps include: (1) Mechanistic studies in the central nervous system of zebrafish to address neurotoxicity; (2) Behavioral assays in zebrafish that assess the effects of BPF on anxiolytic, social, and fear-related behaviors; (3) Studies that broaden understanding of potential endocrine disrupting effects of BPF, for example insulin signaling is predicted to be sensitive to BPF exposure; (4) Studies into metabolic disruption with a focus on glutathione and aromatic amino acids, based upon pathway analysis data; (5) Studies utilizing mixture exposures with other BPA analogs to reflect environmental conditions more accurately.

Intranasal delivery of SARS-CoV-2 spike protein is sufficient to cause olfactory damage, inflammation and olfactory dysfunction in zebrafish

Anosmia, loss of smell, is a prevalent symptom of SARS-CoV-2 infection. Anosmia may be explained by several mechanisms driven by infection of non-neuronal cells and damage in the nasal epithelium rather than direct infection of olfactory sensory neurons (OSNs). Previously, we showed that viral proteins are sufficient to cause neuroimmune responses in the teleost olfactory organ (OO). We hypothesize that SARS-CoV-2 spike (S) protein is sufficient to cause olfactory damage and olfactory dysfunction. Using an adult zebrafish model, we report that intranasally delivered SARS-CoV-2 S RBD mostly binds to the non-sensory epithelium of the olfactory organ and causes severe olfactory histopathology characterized by loss of cilia, hemorrhages and edema. Electrophysiological recordings reveal impaired olfactory function to both food and bile odorants in animals treated intranasally with SARS-CoV-2 S RBD. However, no loss of behavioral preference for food was detected in SARS-CoV-2 S RBD treated fish. Single cell RNA-Seq of the adult zebrafish olfactory organ indicated widespread loss of olfactory receptor expression and inflammatory responses in sustentacular, endothelial, and myeloid cell clusters along with reduced numbers of T_regs. Combined, our results demonstrate that intranasal SARS-CoV-2 S RBD is sufficient to cause structural and functional damage to the zebrafish olfactory system. These findings may have implications for intranasally delivered vaccines against SARS-CoV-2.