Prenatal bisphenol A exposure contributes to Tau pathology: Potential roles of CDK5/GSK3β/PP2A axis in BPA-induced neurotoxicity

Carnosic Acid Attenuated the Motor Impairment by Bisphenol A is Related to the Regulation of Autophagy Through Parkin in In Vitro and In Vivo

Bisphenol A (BPA) is an endocrine-disrupting compound linked to impairments in motor function and the manifestation of anxiety-like behaviors. The present study investigated the effects of carnosic acid (CA) on BPA-induced motor deficits and explored the role of parkin in the autophagic mechanism. First, C57BL/6 J male mice were orally administered with CA (5 mg/kg and 20 mg/kg) or RE (80 mg/kg rosemary extract) to test the motor function and anxiety-like behaviors in BPA (50 μg/kg) treatment. The results showed that CA and RE ameliorate BPA-induced motor impairments and anxiety-like behaviors. Moreover, CA and RE attenuated BPA-induced phosphorylation of tau and α-synuclein while restoring the expression levels of autophagy-related proteins, including parkin, PINK1, PI3K, Atg7, Beclin1, and LC3B-II. Then, SH-SY5Y cells were treated with 20 nM BPA and 1 μM CA or 0.5 μg/mL RE for 18 h. The results showed that treatment of CA and RE with BPA activated the parkin pathway and reduced the levels of Ser396p-tau and p-α-synuclein. Moreover, treatment of CA or RE with BPA restored the parkin signaling, resulting in the upregulation of autophagy-related proteins. However, wortmannin treatment attenuated this restorative effect of CA or RE. Additionally, transfection with parkin siRNA in cells reversed the ability of CA or RE to counteract BPA-induced reductions in autophagy-related proteins and increased the accumulation of misfolded proteins. Therefore, the results indicated that CA and RE improved motor impairments and reduced the accumulation of misfolding proteins induced by BPA, potentially through regulating autophagy by parkin.

Ferulic acid ameliorates bisphenol A (BPA)-induced Alzheimer's disease-like pathology through Akt-ERK crosstalk pathway in male rats

OBJECTIVES

This study investigated the neuroprotective effect of ferulic acid (FA) against bisphenol A (BPA) induced Alzheimer's disease-like pathology in male rats.

METHODS

Rats were allocated into four groups, control, BPA, BPA + FA, and FA, respectively, for 40 days. Spatial working memory and recognition memory were evaluated. Moreover, the brain levels of oxidative stress biomarkers, proinflammatory cytokines, extracellular signal-regulated kinase (ERK), and phosphorylated serine/threonine protein kinase (p-Akt) were measured. We also determined the brain neuropathological protein levels, including Beta-Amyloid 1-42, total Tau (tTau), and phosphorylated Tau (pTau) proteins. Furthermore, brain levels of Acetylcholinesterase (AChE) and Beta-secretase (BACE) were assessed. Brain histological investigation and immunohistochemistry determination of glial fibrillar acidic protein (GFAP) were also performed. Moreover, docking simulation was adapted to understand the inhibitory role of FA on AChE, BACE-1, and ERK1/2.

RESULTS

Interestingly, the BPA + FA treated group showed a reversal in the cognitive impairments induced by BPA, which was associated with improved brain redox status. They also exhibited a significant decrease in brain inflammatory cytokines, ERK, and p-Akt levels. Moreover, they revealed a decline in beta-amyloid 1-42 and a significant improvement in tTau expression and pTau protein levels in the brain tissue. Further, the brain levels of AChE and BACE were substantially reduced in BPA + FA rats. The neuroprotective effect of FA was confirmed by restoring the normal architecture of brain tissue, which was associated with decreasing GFAP.

CONCLUSION

FA could be a potent neuroprotectant agent against AD with a possible prospect for its therapeutic capabilities and nutritional supplement value due to its antioxidant and antiapoptotic properties.

TDCPP promotes apoptosis and inhibits the calcium signaling pathway in human neural stem cells

Tris (1, 3-dichloro-2-propyl) phosphate (TDCPP) is an extensively used organophosphorus flame retardant (OFR). Previous studies have suggested that it has neurotoxic effects, but the neurotoxicity mechanism is still unclear. Neural stem cells are an important in vitro model for studying the neurotoxicity mechanism of pollutants. In this study, we investigated the neurotoxic effects and molecular mechanisms of TDCPP by using human induced pluripotent stem cells (hiPSCs)-derived neural stem cells. We found that TDCPP inhibited the viability of human neural stem cells (hNSCs), stimulated the generation of ROS, arrested the cell cycle in the S phase, and promoted apoptosis. A total of 387 differentially expressed genes were screened out by transcriptome sequencing analysis, and KEGG enrichment analysis showed that the "calcium signaling pathway" was the most significantly enriched. Further studies on the calcium signaling pathway showed that TDCPP disrupted intracellular calcium homeostasis and inhibited the activation of the Ca2+/CALM/CaN/CAMK signaling pathway and the expression levels of NFATC2 and GSK3β. In conclusion, TDCPP has significant toxicity on the calcium signaling pathway of human neural stem cells, which may affect the development process of the human nervous system.

Maternal Bisphenol A Exposure Induces Hippocampal-Dependent Learning and Memory Deficits Through the PI3K/Akt/mTOR Pathway in Male Offspring Rats

Bisphenol A (BPA), an environmental endocrine disrupting chemical, is one of the most widely used chemicals in the world and is widely distributed in the external environment, specifically in food, water, dust, and soil. BPA exposure is associated with abnormal cognitive behaviors. However, the underlying mechanism remains unclear. In this study, pregnant female Sprague Dawley rats were orally exposed to BPA at a low dose of 0, 0.04, 0.4, or 4 mg per kg·of body weight per day from embryonic Day 0 (ED 0) to postnatal Day 21 (PND 21). Spatial learning and memory were measured via a Morris water maze test on PND 22. PI3K/Akt/mTOR signaling pathway protein expression was detected in the hippocampi of male offspring using a western blot. The water maze test demonstrated that BPA exposure considerably reduced the learning and memory capacities of the male offspring exposure groups when compared to the control group. The male offspring rats' latency to escape increased significantly, the time taken to traverse a platform reduced, and latency to find a hidden platform showed an increasing trend. Meanwhile, maternal exposure to BPA downregulated the expression of PI3K/Akt/mTOR/p70S6K pathway in the hippocampi of the offspring. Moreover, BPA exposure improved the GSK3β and phosphorylated tau protein (T231) levels, increased malondialdehyde levels, and activated caspase-3 expression in the hippocampi of the male offspring rats. Taken together, these findings indicate that maternal exposure to BPA causes learning and memory impairment and that the PI3K/Akt/mTOR pathway participates in the mechanism of BPA-induced neurocognitive decline.

Induction of Phosphorylated Tau Accumulation and Memory Impairment by Bisphenol A and the Protective Effects of Carnosic Acid in In Vitro and In Vivo

Bisphenol A (BPA) is a component of polycarbonate plastics that has been implicated in memory impairment. The present study investigated the effect of carnosic acid (CA) on memory deficit induced by BPA and the role of Akt in this mechanism. First, SH-SY5Y cells were treated with 20 nM BPA and 1 μM CA for 12 h. The results showed that treatment of CA with BPA improved the alternation of IRS-1/Akt/GSK-3β as well as the induction of ApoE and Ser396p-tau. Moreover, treatment of CA with BPA restored the signaling involved in long-term potentiation (LTP) effect, leading to induction of synaptic-related proteins, such as PSD-95, synapsin1a, and pro-BDNF. Wortmannin treatment alleviated the reversal by CA. Then, C57BL/6 J male mice were orally administered with CA to test the memory function in BPA treatment. The results showed that CA and RE can improve BPA-induced impairment of motor, recognition, and spatial memory by using open-field test (OFT), novel objective recognition test (NOR), and Y-maze test, respectively. Moreover, CA and RE improved the phosphorylation of tau and the reduction of PSD-95, synapsin1a, and pro-BDNF proteins induced by BPA. Therefore, the results indicated that CA decreased the phosphorylated tau and memory impairment induced by BPA through Akt pathway.

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

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

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.

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.

Early-Life Environment Influence on Late-Onset Alzheimer's Disease

With the expand of the population's average age, the incidence of neurodegenerative disorders has dramatically increased over the last decades. Alzheimer disease (AD) which is the most prevalent neurodegenerative disease is mostly sporadic and primarily characterized by cognitive deficits and neuropathological lesions such as amyloid -β (Aβ) plaques and neurofibrillary tangles composed of hyper- and/or abnormally phosphorylated Tau protein. AD is considered a complex disease that arises from the interaction between environmental and genetic factors, modulated by epigenetic mechanisms. Besides the well-described cognitive decline, AD patients also exhibit metabolic impairments. Metabolic and cognitive perturbations are indeed frequently observed in the Developmental Origin of Health and Diseases (DOHaD) field of research which proposes that environmental perturbations during the perinatal period determine the susceptibility to pathological conditions later in life. In this review, we explored the potential influence of early environmental exposure to risk factors (maternal stress, malnutrition, xenobiotics, chemical factors … ) and the involvement of epigenetic mechanisms on the programming of late-onset AD. Animal models indicate that offspring exposed to early-life stress during gestation and/or lactation increase both AD lesions, lead to defects in synaptic plasticity and finally to cognitive impairments. This long-lasting epigenetic programming could be modulated by factors such as nutriceuticals, epigenetic modifiers or psychosocial behaviour, offering thus future therapeutic opportunity to protect from AD development.

A targeted review on fate, occurrence, risk and health implications of bisphenol analogues

Due to its widespread applications and its ubiquitous occurrence in the environment, bisphenol A (BPA) and its alternatives have gained increasing attention, especially in terms of human safety. Like BPA, alternatives such as bisphenol S (BPS), bisphenol F (BPF), and bisphenol AF (BPAF) have also been identified to be endocrine-disrupting chemicals (EDCs). Hence, in this study, we reviewed the literature of BPA and its alternatives mainly published between the period 2018-2020, including their occurrences in the environment, human exposure, and adverse health effects. The review shows that bisphenols are prevalent in the environment with BPA, BPS, and BPF being the most ubiquitous in the environment worldwide, though BPA remains the most abundant bisphenol. However, the levels of BPS and BPF in different environmental media have been constantly increasing and their fates and health risks are being evaluated. The studies show that humans and animals are exposed to bisphenols in many different ways through inhalation and ingestion and the exposure can have serious health effects. Urinary bisphenols (BPs) levels were frequently reported to be positively associated with different health problems such as cancer, infertility, cardiovascular diseases, diabetes and neurodegenerative diseases. Our literature study also shows that BPs generate reactive oxygen species and disrupt various signalling pathways, which could lead to the development of chronic diseases. Activated carbon-based and chitosan-based sorbents have been widely utilized in the removal of BPA in aqueous solutions. In addition, enzymes and microorganisms have also been getting much attention due to their high removal efficiencies.

Small Molecule Inhibitors of DYRK1A Identified by Computational and Experimental Approaches

Dual-specificity tyrosine phosphorylation-regulated kinase 1A (DYRK1A) is a protein kinase with diverse functions in cell regulation. Abnormal expression and activity of DYRK1A contribute to numerous human malignancies, Down syndrome, and Alzheimer's disease. Notably, DYRK1A has been proposed as a potential therapeutic target for the treatment of diabetes because of its key role in pancreatic β-cell proliferation. Consequently, DYRK1A is an attractive drug target for a variety of diseases. Here, we report the identification of several DYRK1A inhibitors using our in-house topological water network-based approach. All inhibitors were further verified by in vitro assay.