Dynamin-related Protein 1 Inhibition Mitigates Bisphenol A-mediated Alterations in Mitochondrial Dynamics and Neural Stem Cell Proliferation and Differentiation

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.

Deciphering the molecular mechanism of NLRP3 in BPA-mediated toxicity: Implications for targeted therapies

Bisphenol-A (BPA), a pervasive industrial chemical used in polymer synthesis, is found in numerous consumer products including food packaging, medical devices, and resins. Detectable in a majority of the global population, BPA exposure occurs via ingestion, inhalation, and dermal routes. Extensive research has demonstrated the adverse health effects of BPA, particularly its disruption of immune and endocrine systems, along with genotoxic potential. This review focuses on the complex relationship between BPA exposure and the NOD-like receptor protein 3 (NLRP3) inflammasome, a multiprotein complex central to inflammatory disease processes. We examine how BPA induces oxidative stress through the generation of intracellular free radicals, subsequently activating NLRP3 signaling. The mechanistic details of this process are explored, including the involvement of signaling cascades such as PI3K/AKT, JAK/STAT, AMPK/mTOR, and ERK/MAPK, which are implicated in NLRP3 inflammasome activation. A key focus of this review is the wide-ranging organ toxicities associated with BPA exposure, including hepatic, renal, gastrointestinal, and cardiovascular dysfunction. We investigate the immunopathogenesis and molecular pathways driving these injuries, highlighting the interplay among BPA, oxidative stress, and the NLRP3 inflammasome. Finally, this review explores the emerging concept of targeting NLRP3 as a potential therapeutic strategy to mitigate the organ toxicities stemming from BPA exposure. This work integrates current knowledge, emphasizes complex molecular mechanisms, and promotes further research into NLRP3-targeted interventions.

Potential involvement of ferroptosis in BPA-induced neurotoxicity: An in vitro study

BACKGROUND

Ferroptosis is a newly recognized cell death pathway having distinct characteristics compared to traditional cell death pathways such as apoptosis, necroptosis, or autophagy. However, the potential involvement of ferroptosis in bisphenol A (BPA)-induced neurotoxicity has not been well explored so far. In present study, we analyzed the relationship between ferroptosis and BPA-induced neurotoxicity.

METHODS

In this study, a human neuroblastoma cell line, SH-SY5Y, was treated with BPA, ferrostatin-1 (FS-1, ferroptosis inhibitor) and RSL-3 (ferroptosis inducer). The cell viability was measured using MTT assay. Additionally, the levels of lipid peroxidation, total iron content, reactive oxygen species (ROS) generation, and nitrite content were measured to evaluate the key markers of ferroptosis. To further confirm the involvement of ferroptosis in BPA-induced neurotoxicity, other ferroptosis markers such as glutathione peroxidase (GPx) activity, total glutathione contents and antioxidant parameters were also evaluated.

RESULTS

The cell viability of SH-SY5Y cells was down-regulated by BPA treatment in a concentration-dependent manner, the cell viability at 0.1 µM concentration was 97.63% whereas at highest BPA concentration i.e. 10 µM, the cell viability was 86.05% (p < 0.0001). Also the antioxidant parameters including catalase and superoxide dismutase activity of neuronal cells were down-regulated upon BPA exposure. However, the levels of lipid peroxidation, total iron, reactive oxygen species, and nitrite contents were increased in a concentration-dependent manner which could be rescued by FS-1 and exacerbated by RSL-3. The total iron in SH-SY5Y cells at 0.1 µM concentration was found to be 1.2 fold (p < 0.05) of control and at highest BPA concentration total iron was about 1.41 fold (p < 0.001) of control.

CONCLUSIONS

The present study indicated that, ferroptosis plays an important role in the progression of BPA-induced neurotoxicity, and ferroptosis may become a novel target in the treatment of various neurological disorders.

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.

Mystery of bisphenol F-induced nonalcoholic fatty liver disease-like changes: Roles of Drp1-mediated abnormal mitochondrial fission in lipid droplet deposition

As one of the major substitutes for bisphenol A (BPA), bisphenol F (BPF) has been widely used. Our previous study demonstrated that BPF exposure facilitates lipid droplet deposition in hepatic cells, contributing to nonalcoholic fatty liver disease (NAFLD)-like changes. However, the underlying mechanisms remain poorly understood. Here, with a metabolic cage system, we observed the perturbation of energy metabolism in mice treated with BPF. BPF obviously suppressed metabolic capacity, which manifested as decreased energy expenditure, low O2 consumption and CO2 levels in mice. Consistent with the in vivo results, a Seahorse XF Cell Mito Stress Test showed significant reductions in mitochondrial ATP production capacity, maximum respiratory capacity, and residual respiratory capacity after BPF treatment in an in vitro study. Electron microscopy revealed a striking increase in mitochondrial fission that was synchronous with excessive expression and activation of dynamin-related protein 1 (Drp1). Intriguingly, chemical inhibition of Drp1 by Mdivi-1 and/or silencing of Drp1 dramatically hampered mitochondrial fission and ameliorated BPF-induced lipid droplet deposition both in mouse liver and human hepatic cells. Mechanistically, mitochondrial dynamics imbalance played prominent roles in these processes, since suppression of Drp1 by chemical inhibition or knockdown substantially reversed BPF-induced mitochondrial fission and ameliorated the suppression of mitochondrial metabolism as well as excessive mitochondrial ROS, which was verified to be key to lipid droplet deposition. Collectively, the findings of the current study reveal previously unrecognized effects involving Drp1-mediated mitochondrial injury in BPF-induced lipid droplet deposition. Therefore, targeted intervention against mitochondrial dysfunction may be a promising therapeutic strategy for BPF-induced NAFLD-like changes.

Bisphenol-A disturbs hormonal levels and testis mitochondrial activity, reducing male fertility

STUDY QUESTION

How does bisphenol-A (BPA) influence male fertility, and which mechanisms are activated following BPA exposure?

SUMMARY ANSWER

BPA exposure causes hormonal disruption and alters mitochondrial dynamics and activity, ultimately leading to decreased male fertility.

WHAT IS KNOWN ALREADY

As public health concerns following BPA exposure are rising globally, there is a need to understand the exact mechanisms of BPA on various diseases. BPA exposure causes hormonal imbalances and affects male fertility by binding the estrogen receptors (ERs), but the mechanism of how it mediates the hormonal dysregulation is yet to be studied.

STUDY DESIGN SIZE DURATION

This study consisted of a comparative study using mice that were separated into a control group and a group exposed to the lowest observed adverse effect level (LOAEL) (n = 20 mice/group) after a week of acclimatization to the environment. For this study, the LOAEL established by the US Environmental Protection Agency of 50 mg/kg body weight (BW)/day of BPA was used. The control mice were given corn oil orally. Based on the daily variations in BW, both groups were gavaged every day from 6 to 11 weeks (6-week exposure). Before sampling, mice were stabilized for a week. Then, the testes and spermatozoa of each mouse were collected to investigate the effects of BPA on male fertility. IVF was carried out using the cumulus-oocyte complexes from female hybrid B6D2F1/CrljOri mice (n = 3) between the ages of eight and twelve weeks.

PARTICIPANTS/MATERIALS SETTING METHODS

Signaling pathways, apoptosis, and mitochondrial activity/dynamics-related proteins were evaluated by western blotting. ELISA was performed to determine the levels of sex hormones (FSH, LH, and testosterone) in serum. Hematoxylin and eosin staining was used to determine the effects of BPA on histological morphology and stage VII/VIII testicular seminiferous epithelium. Blastocyst formation and cleavage development rate were evaluated using IVF.

MAIN RESULTS AND THE ROLE OF CHANCE

BPA acted by binding to ERs and G protein-coupled receptors and activating the protein kinase A and mitogen-activated protein kinase signaling pathways, leading to aberrant hormone levels and effects on the respiratory chain complex, ATP synthase and protein-related apoptotic pathways in testis mitochondria (P < 0.05). Subsequently, embryo cleavage and blastocyst formation were reduced after the use of affected sperm, and abnormal morphology of seminiferous tubules and stage VII and VIII seminiferous epithelial cells (P < 0.05) was observed. It is noteworthy that histopathological lesions were detected in the testes at the LOAEL dose, even though the mice remained generally healthy and did not exhibit significant changes in BW following BPA exposure. These observations suggest that testicular toxicity is more than a secondary outcome of compromised overall health in the mice due to systemic effects.

LARGE SCALE DATA

Not applicable.

LIMITATIONS REASONS FOR CAUTION

Since the protein expression levels in the testes were validated, in vitro studies in each testicular cell type (Leydig cells, Sertoli cells, and spermatogonial stem cells) would be required to shed further light on the exact mechanism resulting from BPA exposure. Furthermore, the BPA doses employed in this study significantly exceed the typical human exposure levels in real-life scenarios. Consequently, it is imperative to conduct experiments focusing on the effects of BPA concentrations more in line with daily human exposures to comprehensively assess their impact on testicular toxicity and mitochondrial activity.

WIDER IMPLICATIONS OF THE FINDINGS

These findings demonstrate that BPA exposure impacts male fertility by disrupting mitochondrial dynamics and activities in the testes and provides a solid foundation for subsequent investigations into the effects on male reproductive function and fertility following BPA exposure, and the underlying mechanisms responsible for these effects. In addition, these findings suggest that the LOAEL concentration of BPA demonstrates exceptional toxicity, especially when considering its specific impact on the testes and its adverse consequences for male fertility by impairing mitochondrial activity. Therefore, it is plausible to suggest that BPA elicits distinct toxicological responses and mechanistic endpoints based on the particular concentration levels for each target organ.

STUDY FUNDING/COMPETING INTERESTS

This work was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2018R1A6A1A03025159). No competing interests are declared.

Nrf2-mediated protective effect of alpha-lipoic acid on synaptic oxidative damage and inhibition of PKC/ERK/CREB pathway in bisphenol A-exposed HT-22 cells

The harmful effects of bisphenol A (BPA) on learning and memory may involve hippocampal oxidative damage; however, the underlying mechanism remains unclear. Antioxidants that antagonize BPA-induced neuronal oxidative damage lack research. This study aimed to develop an in vitro model using the HT-22 mouse hippocampal neuronal cell line to investigate the neurotoxic mechanism of BPA and the protective effect of alpha-lipoic acid (ALA) on nuclear factor erythroid 2-related factor 2 (Nrf2) inhibition. The results showed that ALA reduced BPA-induced reactive oxygen species and neuronal nitric oxide synthase (nNOS) levels; however, inhibiting Nrf2 weakened the protective effects of ALA. BPA reduced mitochondrial complex I/III activity and ATP levels, but ALA ameliorated this damage. ALA improved the BPA-induced downregulation of the kelch-like ECH-associated protein 1 (keap1)/Nrf2 system, synaptic-related proteins, and the protein kinase C (PKC)/extracellular signal-regulated kinase (ERK)/cAMP response element binding protein (CREB) pathway; however, the protective effects of ALA were weakened when Nrf2 was inhibited. Our results suggest that BPA causes oxidative damage to HT-22 cells by damaging mitochondrial function, nNOS, and the keap1/Nrf2 system, thereby impairing synaptic-related proteins and the PKC/ERK/CREB pathway. ALA counters BPA-induced damage via Nrf2, which may be a significant target for the protective action of ALA.

Proteomics and disease network associations evaluation of environmentally relevant Bisphenol A concentrations in a human 3D neural stem cell model

Bisphenol A (BPA) exposure is associated with a plethora of neurodevelopmental abnormalities and brain disorders. Previous studies have demonstrated BPA-induced perturbations to critical neural stem cell (NSC) characteristics, such as proliferation and differentiation, although the underlying molecular mechanisms remain under debate. The present study evaluated the effects of a repeated-dose exposure of environmentally relevant BPA concentrations during the in vitro 3D neural induction of human induced pluripotent stem cells (hiPSCs), emulating a chronic exposure scenario. Firstly, we demonstrated that our model is suitable for NSC differentiation during the early stages of embryonic brain development. Our morphological image analysis showed that BPA exposure at 0.01, 0.1 and 1 µM decreased the average spheroid size by day 21 (D21) of the neural induction, while no effect on cell viability was detected. No alteration to the rate of the neural induction was observed based on the expression of key neural lineage and neuroectodermal transcripts. Quantitative proteomics at D21 revealed several differentially abundant proteins across all BPA-treated groups with important functions in NSC proliferation and maintenance (e.g., FABP7, GPC4, GAP43, Wnt-8B, TPPP3). Additionally, a network analysis demonstrated alterations to the glycolytic pathway, potentially implicating BPA-induced changes to glycolytic signalling in NSC proliferation impairments, as well as the pathophysiology of brain disorders including intellectual disability, autism spectrum disorders, and amyotrophic lateral sclerosis (ALS). This study enhances the current understanding of BPA-related NSC aberrations based mostly on acute, often high dose exposures of rodent in vivo and in vitro models and human GWAS data in a novel human 3D cell-based model with real-life scenario relevant prolonged and low-level exposures, offering further mechanistic insights into the ramifications of BPA exposure on the developing human brain and consequently, later life neurological disorders.

Targeting dynamin-related protein-1 as a potential therapeutic approach for mitochondrial dysfunction in Alzheimer's disease

Alzheimer's disease (AD) is a neurodegenerative disease that manifests its pathology through synaptic damage, mitochondrial abnormalities, microRNA deregulation, hormonal imbalance, increased astrocytes & microglia, accumulation of amyloid β (Aβ) and phosphorylated Tau in the brains of AD patients. Despite extensive research, the effective treatment of AD is still unknown. Tau hyperphosphorylation and mitochondrial abnormalities are involved in the loss of synapses, defective axonal transport and cognitive decline in patients with AD. Mitochondrial dysfunction is evidenced by enhanced mitochondrial fragmentation, impaired mitochondrial dynamics, mitochondrial biogenesis and defective mitophagy in AD. Hence, targeting mitochondrial proteins might be a promising therapeutic strategy in treating AD. Recently, dynamin-related protein 1 (Drp1), a mitochondrial fission protein, has gained attention due to its interactions with Aβ and hyperphosphorylated Tau, altering mitochondrial morphology, dynamics, and bioenergetics. These interactions affect ATP production in mitochondria. A reduction in Drp1 GTPase activity protects against neurodegeneration in AD models. This article provides a comprehensive overview of Drp1's involvement in oxidative damage, apoptosis, mitophagy, and axonal transport of mitochondria. We also highlighted the interaction of Drp1 with Aβ and Tau, which may contribute to AD progression. In conclusion, targeting Drp1 could be a potential therapeutic approach for preventing AD pathology.

HIV-1 gp120 protein promotes HAND through the calcineurin pathway activation

For over two decades, highly active antiretroviral therapy (HAART) was able to help prolong the life expectancy of people living with HIV-1 (PLWH) and eliminate the virus to an undetectable level. However, an increased prevalence of HIV- associated neurocognitive disorders (HAND) was observed. These symptoms range from neuronal dysfunction to cell death. Among the markers of neuronal deregulation, we cite the alteration of synaptic plasticity and neuronal communications. Clinically, these dysfunctions led to neurocognitive disorders such as learning alteration and loss of spatial memory, which promote premature brain aging even in HAART-treated patients. In support of these observations, we showed that the gp120 protein deregulates miR-499-5p and its downstream target, the calcineurin (CaN) protein. The gp120 protein also promotes the accumulation of calcium (Ca2+) and reactive oxygen species (ROS) inside the neurons leading to the activation of CaN and the inhibition of miR-499-5p. gp120 protein also caused mitochondrial fragmentation and changes in shape and size. The use of mimic miR-499 restored mitochondrial functions, appearance, and size. These results demonstrated the additional effect of the gp120 protein on neurons through the miR-499-5p/calcineurin pathway.

Paraquat-induced neurogenesis abnormalities via Drp1-mediated mitochondrial fission

Neurogenesis is a fundamental process in the development and plasticity of the nervous system, and its regulation is tightly linked to mitochondrial dynamics. Imbalanced mitochondrial dynamics can result in oxidative stress, which has been implicated in various neurological disorders. Paraquat (PQ), a commonly used agricultural chemical known to be neurotoxic, induces oxidative stress that can lead to mitochondrial fragmentation. In this study, we investigated the effects of PQ on neurogenesis in primary murine neural progenitor cells (mNPCs) isolated from neonatal C57BL/6 mice. We treated the mNPCs with 0-40 μM PQ for 24 h and observed that PQ inhibited their proliferation, migration, and differentiation into neurons in a concentration-dependent manner. Moreover, PQ induced excessive mitochondrial fragmentation and upregulated the expression of Drp-1, p-Drp1, and Fis-1, while downregulating the expression of Mfn2 and Opa1. To confirm our findings, we used Mdivi-1, an inhibitor of mitochondrial fission, which reversed the adverse effects of PQ on neurogenesis, particularly differentiation into neurons and migration of mNPCs. Additionally, we found that Mito-TEMPO, a mitochondria-targeted antioxidant, ameliorated excessive mitochondrial fragmentation caused by PQ. Our study suggests that PQ exposure impairs neurogenesis by inducing excessive mitochondrial fission and abnormal mitochondrial fragmentation via oxidative stress. These findings identify mitochondrial fission as a potential therapeutic target for PQ-induced neurotoxicity. Further research is needed to elucidate the underlying mechanisms of mitochondrial dynamics and neurogenesis in the context of oxidative stress-induced neurological disorders.

Re-evaluation of the risks to public health related to the presence of bisphenol A (BPA) in foodstuffs

In 2015, EFSA established a temporary tolerable daily intake (t-TDI) for BPA of 4 μg/kg body weight (bw) per day. In 2016, the European Commission mandated EFSA to re-evaluate the risks to public health from the presence of BPA in foodstuffs and to establish a tolerable daily intake (TDI). For this re-evaluation, a pre-established protocol was used that had undergone public consultation. The CEP Panel concluded that it is Unlikely to Very Unlikely that BPA presents a genotoxic hazard through a direct mechanism. Taking into consideration the evidence from animal data and support from human observational studies, the immune system was identified as most sensitive to BPA exposure. An effect on Th17 cells in mice was identified as the critical effect; these cells are pivotal in cellular immune mechanisms and involved in the development of inflammatory conditions, including autoimmunity and lung inflammation. A reference point (RP) of 8.2 ng/kg bw per day, expressed as human equivalent dose, was identified for the critical effect. Uncertainty analysis assessed a probability of 57-73% that the lowest estimated Benchmark Dose (BMD) for other health effects was below the RP based on Th17 cells. In view of this, the CEP Panel judged that an additional uncertainty factor (UF) of 2 was needed for establishing the TDI. Applying an overall UF of 50 to the RP, a TDI of 0.2 ng BPA/kg bw per day was established. Comparison of this TDI with the dietary exposure estimates from the 2015 EFSA opinion showed that both the mean and the 95th percentile dietary exposures in all age groups exceeded the TDI by two to three orders of magnitude. Even considering the uncertainty in the exposure assessment, the exceedance being so large, the CEP Panel concluded that there is a health concern from dietary BPA exposure.

Bisphenol-A (BPA) Impairs Hippocampal Neurogenesis via Inhibiting Regulation of the Ubiquitin Proteasomal System

The ubiquitin-proteasome system (UPS) controls protein homeostasis to maintain cell functionality and survival. Neurogenesis relies on proteasome function, and a defective proteasome system during brain development leads to neurological disorders. An endocrine-disrupting xenoestrogen bisphenol-A (BPA) used in plastic products adversely affects human health and causes neurotoxicity. Previously, we reported that BPA reduces neural stem cells (NSCs) proliferation and differentiation, impairs myelination and mitochondrial protein import, and causes excessive mitochondrial fragmentation leading to cognitive impairments in rats. Herein, we examined the effect(s) of prenatal BPA exposure on UPS functions during NSCs proliferation and differentiation in the hippocampus. Rats were orally treated with 40 µg/kg body weight BPA during day 6 gestation to day 21 postnatal. BPA significantly reduced proteasome activity in a cellular extract of NSCs. Immunocytochemistry exhibited a significant reduction of 20S proteasome/Nestin⁺ and PSMB5/Nestin⁺ cells in NSCs culture. BPA decreased 20S/Tuj1⁺ and PSMB5/Tuj1⁺ cells, indicating disrupted UPS during neuronal differentiation. BPA reduced the expression of UPS genes, 20S, and PSMB5 protein levels and proteasome activity in the hippocampus. It significantly reduced overall protein synthesis by the loss of Nissl substances in the hippocampus. Pharmacological activation of UPS by a bioactive triterpenoid 18α-glycyrrhetinic acid (18α GA) caused increased proteasome activities, significantly increased neurosphere size and number, and enhanced NSCs proliferation in BPA exposed culture, while proteasome inhibition by MG132 further aggravates BPA-mediated effects. In silico studies demonstrated that BPA strongly binds to catalytic sites of UPS genes (PSMB5, TRIM11, Parkin, and PSMD4) which may result in UPS inactivation. These results suggest that BPA significantly reduces NSCs proliferation by impairing UPS, and UPS activation by 18α GA could suppress BPA-mediated neurotoxicity and exerts neuroprotection.

Effect of the Enrichment in c-Kit Stem Cell Potential of Foetal Human Amniotic Fluid Cells: Characterization from Single Cell Analysis to the Secretome Content

Human amniotic fluid cells (hAFSCs) are a fascinating foetal cell-type that have important stem cell characteristics; however, they are a heterogeneous population that ranges from totally differentiated or progenitor cells to highly multipotent stem cells. There is no single approach to isolating the stem cell component, but the selection of a subpopulation of hAFSCs expressing c-Kit is widely employed, while a deep characterization of the two populations is still lacking. Here we performed single-cell and bulk RNAseq analysis to compare the gene expression profiles of adherent amniotic fluid cells and their subpopulation c-Kit⁺. Information deriving from this high throughput technology on the transcriptome was then confirmed for specific targets with protein expression experiments and functional analysis. In particular, transcriptome profiling identified changes in cellular distribution among the different clusters that correlated with significant differential expression in pathways related to stemness, proliferation, and cell cycle checkpoints. These differences were validated by RT-PCR, immunofluorescence, WB, and cell cycle assays. Interestingly, the two populations produced secretomes with different immune-modulating and pro-regenerative potentials. Indeed, the presence of TGFβ, HGF, IDO was higher in EVs deriving from c-Kit⁺ cells, unlike IL-6. These results suggest the existence of deep intra-population differences that can influence the stemness profile of hAFSCs. This study represents a proof-of-concept of the importance of selecting c-Kit positive fractions with higher potential in regenerative medicine applications.

Lipopolysaccharides and hydrogen peroxide induce contrasting pathological conditions in dental pulpal cells

AIM

To determine the effects of lipopolysaccharides (LPS), hydrogen peroxide (H₂ O₂ ), and both combined on cell proliferation/differentiation, inflammation, mitochondrial dynamics as indicated by mitochondrial fission/fusion, antioxidants as indicated by superoxide dismutase 2 (SOD2), and apoptosis of human dental pulpal cells (HDPCs).

METHODOLOGY

Pulpal tissues from eight healthy subjects (n = 8) were collected from Faculty of Dentistry, Chiang Mai University. Isolated HDPCs from healthy donors were divided into four experimental groups: vehicle, 20 μg/ml LPS, 400 μM H₂ O₂ , and the two combined. All experimental groups were investigated to assess cell proliferation, mineralization, differentiation, inflammation, mitochondrial dynamics, antioxidants, and apoptosis.

RESULTS

H₂ O₂ and combined agents decreased cell proliferation of HDPCs equally. LPS, H₂ O_2, and both combined decreased mineralization and differentiation with an increase in tumour necrosis factor-alpha (TNF-α) levels. Surprisingly, LPS and combined agents increased SOD2 expression and caused an imbalance in mitochondrial dynamics. A significant increase in apoptosis was observed in the case of H₂ O₂ and combined agents.

CONCLUSIONS

These findings suggest that LPS induced inflammation, imbalanced mitochondrial dynamics, and reduced cell differentiation without altering apoptosis and cell proliferation. However, H₂ O₂ decreased cell proliferation, and differentiation, and increased inflammation, and apoptosis without interfering with mitochondrial dynamics. Based on our findings, combining LPS and H₂ O₂ could be potentially used as the inducers in in vitro study to mimic the clinical pulpitis.

Protective effect of N-acetyl cysteine on the mitochondrial dynamic imbalance in temporal lobe epilepsy: Possible role of mTOR

Understanding the underlying molecular mechanisms involved in epilepsy is critical for the development of more effective therapies. It is believed that mTOR (Mechanistic Target of Rapamycin kinases) activity and the mitochondrial dynamic balance change during epilepsy. mTOR affects mitochondrial fission by stimulating the translation of mitochondrial fission process 1 (MTFP1). In This study, the protective role of N-acetylcysteine was studied in temporal lobe epilepsy (TLE) through the regulation of mTOR and mitochondrial dynamic proteins. Rats received N-acetylcysteine (oral administration) seven days before induction of epilepsy, followed by one day after epilepsy. TLE was induced by microinjection of kainite into the left lateral ventricle. The total mTOR and Drp1 levels in the hippocampus were evaluated by western blotting. MFN1 was assessed using immunohistochemistry, and the expression of Fis.1 and MTFP1 (fission-related proteins) and OPA (fusion-related protein) were detected by real-time PCR. The mitochondrial membrane potential was measured by Rhodamin 123. The results showed that 72 h after induction of epilepsy, the mTOR protein level increased, and the balance of the mitochondrial dynamic was disturbed; however, oral administration of NAC decreased the mTOR protein level and improved the mitochondrial dynamic. These findings indicate that NAC plays a neuroprotective role in temporal lobe epilepsy, probably through decreasing the mTOR protein level, which can improve the imbalance in the mitochondrial dynamic.

Impact of Bisphenol A on Structure and Function of Mitochondria: A Critical Review

Bisphenol A (BPA) is an industrial chemical used extensively to manufacture polycarbonate plastics and epoxy resins. Because of its estrogen-mimicking properties, BPA acts as an endocrine-disrupting chemical. It has gained attention due to its high chances of daily and constant human exposure, bioaccumulation, and the ability to cause cellular toxicities and diseases at extremely low doses. Several elegant studies have shown that BPA can exert cellular toxicities by interfering with the structure and function of mitochondria, leading to mitochondrial dysfunction. Exposure to BPA results in oxidative stress and alterations in mitochondrial DNA (mtDNA), mitochondrial biogenesis, bioenergetics, mitochondrial membrane potential (MMP) decline, mitophagy, and apoptosis. Accumulation of reactive oxygen species (ROS) in conjunction with oxidative damage may be responsible for causing BPA-mediated cellular toxicity. Thus, several reports have suggested using antioxidant treatment to mitigate the toxicological effects of BPA. The present literature review emphasizes the adverse effects of BPA on mitochondria, with a comprehensive note on the molecular aspects of the structural and functional alterations in mitochondria in response to BPA exposure. The review also confers the possible approaches to alleviate BPA-mediated oxidative damage and the existing knowledge gaps in this emerging area of research.

Bisphenol A exposure modulates reproductive and endocrine system, mitochondrial function and cellular senescence in female adult rats: A hallmarks of polycystic ovarian syndrome phenotype

Bisphenol A (BPA) mimics estrogen and consequently suspected to be detrimental to female reproductive system. Biomonitoring confirms the BPA burden in body leading to a complex condition called polycystic ovarian syndrome (PCOS) which is frequently attributed to female infertility. Due to unclear precise molecular pathomechanisms of BPA in PCOS, we intend to examine the molecular mechanisms of the reproductive, endocrine, mitochondrial features, and cellular senescence in BPA-treated rats. We analyzed vaginal smears and ovarian follicles using microscope, assessed sex hormones by ELISA, analyzed BPA target gene expression by semi-quantitative RT-PCR, assessed senescence induction by β-galactosidase staining and immunofluorescence in BPA-treated rats. Our data showed hormonal imbalance, impaired folliculogenesis, abnormal expression patterns of target genes, CDKN2A overexpression and enhanced ROS levels in BPA-treated rats. This study provides insights on the effects of BPA exposure on ovulatory, hormonal, mitochondrial dysfunction, and senescence that benefit in better understanding of PCOS induced by BPA.

Neuroprotective effect of Biochanin a against Bisphenol A-induced prenatal neurotoxicity in zebrafish by modulating oxidative stress and locomotory defects

Exogenous toxicants cause oxidative stress and damage to brain cells, resulting in inflammation. Neuroinflammation is important in the pathobiology of various neurological illnesses, including Alzheimer's disease (AD). In this context, Bisphenol A (BPA), a common toxin, causes oxidative damage and has been linked to neurological problems. An O-methylated isoflavone known as Biochanin A (5,7-dihydroxy-4'-methoxy-isoflavone, BCA) is considered to be a phytoestrogen, which is abundant in some legume plants and soy which have preventive effects against cancer, osteoporosis, menopausal symptoms and oxidative stress. However, the mechanism by which BCA protected the prenatal neurological stress are not known. So that, in this study we investigated the BCA neuroprotective effect against BPA-induced neuroinflammation in zebrafish embryo models. For this study, fertilized zebrafish embryos are exposed to BPA (1 µM) with or without BCA. Our finding suggested that BCA co-exposure prevented the depletion of antioxidant defense enzymes by BPA and reduced the production of intracellular ROS production, superoxide anion (O₂^-), lipid peroxidation (LPO), lactate dehydrogenase (LDH) and nitric oxide (NO) levels in the head that aided in safeguarding neuronal development. Baseline locomotion was rendered and a total distance was calculated to assess the motor function. Exposure to BCA increased acetylcholinestrase (AChE) and improved motor neuron functions. It also reduced the pro-inflammatory response expression and prevented neuroinflammation. Our study suggests that BCA has a positive role in the attenuation or amelioration of neuronal oxidative damage and locomotory behaviour induced by BPA.

Mitochondrial Impairment: A Common Motif in Neuropsychiatric Presentation? The Link to the Tryptophan-Kynurenine Metabolic System

Nearly half a century has passed since the discovery of cytoplasmic inheritance of human chloramphenicol resistance. The inheritance was then revealed to take place maternally by mitochondrial DNA (mtDNA). Later, a number of mutations in mtDNA were identified as a cause of severe inheritable metabolic diseases with neurological manifestation, and the impairment of mitochondrial functions has been probed in the pathogenesis of a wide range of illnesses including neurodegenerative diseases. Recently, a growing number of preclinical studies have revealed that animal behaviors are influenced by the impairment of mitochondrial functions and possibly by the loss of mitochondrial stress resilience. Indeed, as high as 54% of patients with one of the most common primary mitochondrial diseases, mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS) syndrome, present psychiatric symptoms including cognitive impairment, mood disorder, anxiety, and psychosis. Mitochondria are multifunctional organelles which produce cellular energy and play a major role in other cellular functions including homeostasis, cellular signaling, and gene expression, among others. Mitochondrial functions are observed to be compromised and to become less resilient under continuous stress. Meanwhile, stress and inflammation have been linked to the activation of the tryptophan (Trp)-kynurenine (KYN) metabolic system, which observably contributes to the development of pathological conditions including neurological and psychiatric disorders. This review discusses the functions of mitochondria and the Trp-KYN system, the interaction of the Trp-KYN system with mitochondria, and the current understanding of the involvement of mitochondria and the Trp-KYN system in preclinical and clinical studies of major neurological and psychiatric diseases.

Bisphenol-A Mediated Impaired DRP1-GFER Axis and Cognition Restored by PGC-1α Upregulation Through Nicotinamide in the Rat Brain Hippocampus

The regulatory network of mitochondrial biogenesis and dynamics is vital for mitochondrial functions and cellular homeostasis. Any impairment in the mitochondrial network leads to neurodegenerative disorders. Our earlier studies suggest that environmental toxicant Bisphenol-A (BPA) exposure reduces neurogenesis by abnormal mitochondrial dynamics and mitochondrial biogenesis through impairment of mitochondrial fission factor dynamin-related protein (DRP1) and mitochondrial import protein GFER, which leads to demyelination, neurodegeneration, and cognitive deficits in the rats. In the present study, we found that chronic BPA exposure reduces PGC-1α levels (master regulator of mitochondrial biogenesis), alters mitochondrial localization of DRP1 and GFER, and reduces the number of PGC-1α/NeuN+ and PGC-1α/β-tubulin+ neurons in the rat hippocampus, suggesting reduced PGC-1α-mediated neurogenesis. Nicotinamide significantly increased PGC-1α protein levels, PGC-1α/NeuN+ co-labeled cells in BPA-treated rat hippocampus and PGC-1α/β-tubulin+ co-labeled cells in neuron culture derived from hippocampal neural stem cells. Interestingly, PGC-1α upregulation by nicotinamide also resulted in increased GFER levels and restored mitochondrial localization of GFER (increased GFER/TOMM20 co-labeled cells) in vitro and in vivo following BPA treatment. Nicotinamide also reduced DRP1 levels and prevented DRP1 mitochondrial localization in BPA-treated neuronal cultures and hippocampus, suggesting reduced mitochondrial fission. This resulted in reduced cytochrome c levels in neuronal culture and reduced hippocampal neurodegeneration (reduced caspase-3/NeuN+ co-labeled neurons) following nicotinamide treatment in BPA-treated group. Consequently, activation of PGC-1α by nicotinamide restored BPA-mediated cognitive deficits in rats. Results suggest that the treatment of nicotinamide has therapeutic potential and rescues BPA-mediated neuronal death and cognitive deficits by upregulating the PGC-1α and GFER-DRP1 link, thus balancing mitochondrial homeostasis.

The Effect of bisphenol A and Photobiomodulation Therapy on Autophagy-Related Genes Induction in Adipose Tissue-Derived Stem Cells

Introduction: As adipose tissue-derived stem cells (ADSCs) can divide rapidly and be prepared non-invasively, they have extensively been used in regenerative medicine. On the other hand, a new method of therapy, known as photobiomodulation (PHT), has been used to treat many diseases, such as inflammatory conditions, wound healing and pain. Besides, exposure to chemical substances such as bisphenol A (BPA), at low levels, can lead to autophagy. This study investigated the effects of BPA and PHT on the expression of autophagy-related genes, including LC3, NRF2, P62, in rat ADSCs as a model. Methods: ADSCs isolation and purification were confirmed by immunocytochemistry (ICC). The cells were then treated with different concentrations of BPA and also subjected to PHT. Reverse transcription polymerase chain reaction (RT-PCR) was used for the evaluation of LC3, NRF2 and P62 gene expressions. Oil red O staining was used for adipogenic vacuole formation. Result: ICC showed that the isolated cells were CD 49-positive but CD 31 and CD 34-negative. The viability test indicated that the number of live cells after 24 hours in the BPA groups at concentrations of 0, 1, 50, 100 and 200 μM was 100%, 93%, 81%, 72%, and 43% respectively. The difference in cell viability between groups 50, 100 and 200 μM was significant as compared with the control groups (P<0.05). Moreover, in the group with 1 μM concentration of BPA, the expressions of LC3, NRF2 and P62 genes were upregulated. However, in the treatment group at the concentration of 200 μM of BPA, the LC3 gene was expressed, but NRF2 and P62 genes were downregulated. Conclusion: BPA and PHT induce autophagy and adiposeness in ADSCs in a dose-dependent manner.

Evaluation of BPA effects on autophagy in Neuro-2a cells

Bisphenol A (BPA), which is used for the industrial production of polycarbonate plastics and epoxy resins, is found in many commercially available products. Plasticizer BPA produces chemical substances worldwide, and knowledge of its effects on humans and animals is increasing. In the present work, the morphology of cells was observed by optical microscopy and phalloidin staining to evaluate the toxic effect of BPA on Neuro-2a cells. Autophagy has an important role in the regulation of cell metabolism. To study the effect of BPA on the autophagy in Neuro-2a cells, the expression distribution of LC3 was detected by immunofluorescence, and the expression levels of p62 and Beclin1 were determined using western blot and quantitative real-time PCR (qRT-PCR), respectively. Optical microscopy and phalloidin staining revealed that the cells became rounded and small and that the dendritic spine of the cells were reduced at high BPA doses. Immunofluorescence analysis demonstrated that the expression of LC3 fluorescence intensity was weak at increasing BPA concentrations. Western blot results showed that the relative expression of protein p62 increased significantly and that the relative expression levels of the Beclin1 and the LC3 proteins significantly decreased with increasing BPA concentration. qRT-PCR results showed that the relative expression level of autophagy-related p62 mRNA increased significantly and that the relative expression level of Beclin1 mRNA decreased significantly with increasing BPA concentration. The above results indicated that BPA treatment exerted dose-dependent toxic effects on Neuro-2a cells, and BPA inhibited the autophagy level of Neuro-2a cells, thereby providing a new perspective in studying the toxic effect of BPA on Neuro-2a cells.

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.

Role of Bisphenol A in Autophagy Modulation: Understanding the Molecular Concepts and Therapeutic Options

Abstract:

Bisphenol A (4,4′-isopropylidenediphenol) is an organic compound, commonly used in the plastic bottles, packaging containers, beverages and resin industry. The adverse effects of bisphenol A were studied in various systems of the body. Autophagy is a lysosomal degradation process meant for the regeneration of new cells. The role of bisphenol A on autophagy modulation in the pathogenesis of diseases is still debatable. Few research studies showed that bisphenol A-induced adverse effects were associated with autophagy dysregulation, while few showed the activation of autophagy by bisphenol A. Such contrasting views make the subject more interesting and debatable. In the present review, we discuss the different steps of autophagy, genes involved, and the effect of bisphenol A in autophagy modulation on different systems of the body. We also discuss the methods for monitoring autophagy and the roles of drugs such as chloroquine, verteporfin, and rapamycin in autophagy. Proper understanding of the role of bisphenol A in the modulation of autophagy may be important for future treatment and drug discovery.

Neurotoxicity and neuroinflammatory effects of bisphenol A in male rats: the neuroprotective role of grape seed proanthocyanidins

Exposure to bisphenol A (BPA) contributes to neurological disorders, but the underlying mechanisms are still not completely understood. We studied the neurotoxic effect of BPA and how it promotes inflammation and alteration in the neurotransmission synthesis, release, and transmission. This study was also designed to investigate the neuroprotective effect of grape seed proanthocyanidins (GSPE) against BPA-induced neurotoxicity in rats. Rats were equally divided into 4 groups with 7 rats in each: control group, BPA group, GSPE + BPA group, and GSPE group. Rats were orally treated with their respective doses (50 mg BPA/kg BW and/or 200 mg GSPE/kg BW) daily for 70 days. BPA elicits significant elevation in malondialdehyde (MDA) and nitric oxide (NO) associated with a significant reduction in glutathione (GSH), total thiols, glutathione peroxidase (GPx), superoxide dismutase (SOD), and glutathione-S-transferase (GST). BPA exposure results in increased dopamine and serotonin levels, elevation in acetylcholinesterase (AChE) activity, and reduction in Na/K-ATPase and total ATPase activities in the brain. Also, BPA induces upregulation in the gene expression of the inflammatory markers, tumor necrosis factor-α (TNF-α) and cyclooxygenase-2 (COX-2), and in the tumor suppressor and pro-oxidant p53 protein. The pretreatment with GSPE attenuates or ameliorate all the oxidative and neurotoxic parameters induced by BPA. Our results suggest that GSPE has a promising role in modulating BPA-induced neuroinflammation and neurotoxicity and its antioxidant and free radical scavenging activities may in part be responsible for such effects.

Protective Effects of Lignin-Carbohydrate Complexes from Wheat Stalk against Bisphenol a Neurotoxicity in Zebrafish via Oxidative Stress

Lignin-carbohydrate complexes (LCCs) from different lignocellulosic biomass have shown biological qualities as antioxidant and immunostimulant. By contrast, the application of LCCs as protectant against neurotoxicity caused by different compounds is scarce. In this work, two kinds of LCCs with carbohydrate-rich and lignin-rich fractions were obtained from wheat stalk and used to protect against BPA-neurotoxicity in zebrafish. The results showed that BPA at a concentration of 500 µg/L results in neurotoxicity, including significant behavioral inhibition, and prevents the expression of central nervous system proteins in transgenic zebrafish models (Tg (HuC-GFP)). When the zebrafish was treated by LCCs, the reactive oxygen species of zebrafish decreased significantly with the change of antioxidant enzymes and lipid peroxidation, which was due to the LCCs' ability to suppress the mRNA expression level of key genes related to nerves. This is essential in view of the neurotoxicity of BPA through oxidative stress. In addition, BPA exposure had negative effects on the exercise behavior, the catalase (CAT) and superoxide dismutase (SOD) activity, and the larval development and gene expression of zebrafish larvae, and LCC preparations could recover these negative effects by reducing oxidative stress. In zebrafish treated with BPA, carbohydrate-rich LCCs showed stronger antioxidant activity than lignin-rich LCCs, showing their potential as a neuroprotective agents.

Bisphenol a Induces Autophagy Defects and AIF-Dependent Apoptosis via HO-1 and AMPK to Degenerate N2a Neurons

Bisphenol A (BPA) is an environmental contaminant widely suspected to be a neurological toxicant. Epidemiological studies have demonstrated close links between BPA exposure, pathogenetic brain degeneration, and altered neurobehaviors, considering BPA a risk factor for cognitive dysfunction. However, the mechanisms of BPA resulting in neurodegeneration remain unclear. Herein, cultured N2a neurons were subjected to BPA treatment, and neurotoxicity was assessed using neuronal viability and differentiation assays. Signaling cascades related to cellular self-degradation were also evaluated. BPA decreased cell viability and axon outgrowth (e.g., by down-regulating MAP2 and GAP43), thus confirming its role as a neurotoxicant. BPA induced neurotoxicity by down-regulating Bcl-2 and initiating apoptosis and autophagy flux inhibition (featured by nuclear translocation of apoptosis-inducing factor (AIF), light chain 3B (LC3B) aggregation, and p62 accumulation). Both heme oxygenase (HO)-1 and AMP-activated protein kinase (AMPK) up-regulated/activated by BPA mediated the molecular signalings involved in apoptosis and autophagy. HO-1 inhibition or AIF silencing effectively reduced BPA-induced neuronal death. Although BPA elicited intracellular oxygen free radical production, ROS scavenger NAC exerted no effect against BPA insults. These results suggest that BPA induces N2a neurotoxicity characterized by AIF-dependent apoptosis and p62-related autophagy defects via HO-1 up-regulation and AMPK activation, thereby resulting in neuronal degeneration.

Coenzyme Q10 ameliorates BPA-induced apoptosis by regulating autophagy-related lysosomal pathways

Bisphenol A (BPA) is a widely distributed environmental endocrine disruptor. The accumulation of BPA has been proved that produce various toxic effects both on human and animals. However, the strategies to reduce the damage of BPA on the body and related mechanisms remain to be studied. Coenzyme Q10 (CoQ10), as a powerful antioxidant, is ubiquitous in many eukaryotic cells, which can improve the integrity of lysosomal membrane, lysosomal degradation function and promote autophagy. Here, we examined the ability of CoQ10 to alleviate oxidative stress and apoptosis in BPA-induced damages in C2C12 cells, and how to alleviate it. Our results showed that BPA treatment significantly reduced cell viability, increased the number of cell apoptosis and ROS production, decreased mitochondrial membrane potential, and inhibited the gene expression of mitochondria biogenesis. Moreover, we demonstrated that exposure to BPA increased expression levels of autophagy protein (LC3-II, p62), inhibited autophagy flux, and disrupted the acidic pH environment of lysosomes. Importantly, CoQ10 supplementation effectively restored these abnormalities caused by BPA. CoQ10 significantly decreased the apoptotic incidence and ROS levels, improved mitochondrial membrane potential. Moreover, CoQ10 improved lysosome function and enhanced autophagy flux. Taken together, our results indicate that CoQ10 supplementation is a feasible and effective way to promote the level of autophagy by improving lysosomal function, thereby reducing the apoptosis caused by BPA accumulation. This study aims to provide evidence for the role of CoQ10 in repairing BPA-induced cell damage in clinical practice.

How Inflammation Pathways Contribute to Cell Death in Neuro-Muscular Disorders

Neuro-muscular disorders include a variety of diseases induced by genetic mutations resulting in muscle weakness and waste, swallowing and breathing difficulties. However, muscle alterations and nerve depletions involve specific molecular and cellular mechanisms which lead to the loss of motor-nerve or skeletal-muscle function, often due to an excessive cell death. Morphological and molecular studies demonstrated that a high number of these disorders seem characterized by an upregulated apoptosis which significantly contributes to the pathology. Cell death involvement is the consequence of some cellular processes that occur during diseases, including mitochondrial dysfunction, protein aggregation, free radical generation, excitotoxicity and inflammation. The latter represents an important mediator of disease progression, which, in the central nervous system, is known as neuroinflammation, characterized by reactive microglia and astroglia, as well the infiltration of peripheral monocytes and lymphocytes. Some of the mechanisms underlying inflammation have been linked to reactive oxygen species accumulation, which trigger mitochondrial genomic and respiratory chain instability, autophagy impairment and finally neuron or muscle cell death. This review discusses the main inflammatory pathways contributing to cell death in neuro-muscular disorders by highlighting the main mechanisms, the knowledge of which appears essential in developing therapeutic strategies to prevent the consequent neuron loss and muscle wasting.

Drp-1-Dependent Mitochondrial Fragmentation Contributes to Cobalt Chloride-Induced Toxicity in Caenorhabditis elegans

Excess cobalt may lead to metallosis, characterized by sensorineural hearing loss, visual, and cognitive impairment, and peripheral neuropathy. In the present study, we sought to address the molecular mechanisms of cobalt-induced neurotoxicity, using Caenorhabditis elegans as an experimental model. Exposure to cobalt chloride for 2 h significantly decreased the survival rate and lifespan in nematodes. Cobalt chloride exposure led to increased oxidative stress and upregulation of glutathione S-transferase 4. Consistently, its upstream regulator skn-1, a mammalian homolog of the nuclear factor erythroid 2-related factor 2, was activated. Among the mRNAs examined by quantitative real-time polymerase chain reactions, apoptotic activator egl-1, proapoptotic gene ced-9, autophagic (bec-1 and lgg-1), and mitochondrial fission regulator drp-1 were significantly upregulated upon cobalt exposure, concomitant with mitochondrial fragmentation, as determined by confocal microscopy. Moreover, drp-1 inhibition suppressed the cobalt chloride-induced reactive oxygen species generation, growth defects, and reduced mitochondrial fragmentation. Our novel findings suggest that the acute toxicity of cobalt is mediated by mitochondrial fragmentation and drp-1 upregulation.

Fine particles in surgical smoke affect embryonic cardiomyocyte differentiation through oxidative stress and mitophagy

Surgical smoke is widespread in operating rooms, and fine particles are the main toxic components. However, the effect of fine particles in surgical smoke on embryonic development has not yet been studied. This study evaluated the effect of fine particles in surgical smoke on embryonic development and compared it with that of atmospheric fine particles. Afterwards, differentiated cardiomyocytes were purified, and the effect of exposure to fine particles in surgical smoke on cardiomyocyte differentiation was evaluated. Fine particles in surgical smoke exhibited weak embryotoxicity toward an embryonic stem cell test model, and their inhibitory effect on cardiomyocyte differentiation was slightly stronger than that of atmospheric fine particles. Fine particles in surgical smoke specifically inhibited the differentiation of the mesoderm lineage and promoted the differentiation of the ectoderm lineage. Furthermore, fine particles in surgical smoke reduced the beating rate of purified cardiomyocytes, promoted mitophagy, reduced ATP production and increased the reactive oxygen species (ROS) content. Antioxidants attenuated the inhibition of cardiomyocyte differentiation and the reduction in the cardiomyocyte beating rate caused by fine particles in surgical smoke and simultaneously restored mitophagy and other processes to the control levels. However, mitophagy inhibitors treatment blocked only the inhibition of cardiomyocyte differentiation caused by fine particles in surgical smoke; it had little effect on other changes caused by fine particles. Based on the results described above, we propose that fine particles in surgical smoke and atmospheric fine particles exhibit similar levels of toxicity toward embryonic development. Fine particles in surgical smoke potentially affect the beating of cardiomyocytes by damaging mitochondria and increasing oxidative stress.

Bisphenol-A inhibits mitochondrial biogenesis via impairment of GFER mediated mitochondrial protein import in the rat brain hippocampus

Mitochondrial biogenesis relies on different protein import machinery, as mitochondrial proteins are imported from the cytosol. The mitochondrial intermembrane space assembly (MIA) pathway consists of GFER/ALR and CHCHD4/Mia40, responsible for importing proteins and their oxidative folding inside the mitochondria. The MIA pathway plays an essential role in complex IV (COX IV) biogenesis via importing copper chaperone COX17, associated with the respiratory chain. BPA, an environmental toxicant, found in consumable plastics, causes neurotoxicity via impairment in mitochondrial dynamics, neurogenesis, and cognitive functions. We studied the levels of key regulatory proteins of mitochondrial import pathways and mitochondrial biogenesis after BPA exposure in the rat hippocampus. BPA caused a significant reduction in the levels of mitochondrial biogenesis proteins (PGC1α, and TFAM) and mitochondrial import protein (GFER). Immunohistochemical analysis showed reduced co-localization of NeuN with GFER, PGC-1α, and TFAM suggesting impaired mitochondrial biogenesis and protein import. BPA exposure resulted in damaged mitochondria with distorted cristae in neurons and caused a significant reduction in GFER localization inside IMS as depicted by immunogold electron microscopy. The reduced levels of GFER resulted in defective COX17 import. The translocation of cytochrome c into the cytosol and increased cleaved caspase-3 levels triggered apoptosis due to BPA toxicity. Overall, our study implicates GFER as a potential target for impaired mitochondrial protein machinery, biogenesis, and apoptosis against BPA neurotoxicity in the rat hippocampus.

Nanomedicine against Alzheimer's and Parkinson's Disease

Alzheimer's and Parkinson's are the two most rampant neurodegenerative disorders worldwide. Existing treatments have a limited effect on the pathophysiology but are unable to fully arrest the progression of the disease. This is due to the inability of these therapeutic molecules to efficiently cross the blood-brain barrier. We discuss how nanotechnology has enabled researchers to develop novel and efficient nano-therapeutics against these diseases. The development of nanotized drug delivery systems has permitted an efficient, site-targeted, and controlled release of drugs in the brain, thereby presenting a revolutionary therapeutic approach. Nanoparticles are also being thoroughly studied and exploited for their role in the efficient and precise diagnosis of neurodegenerative conditions. We summarize the role of different nano-carriers and RNAi-conjugated nanoparticle-based therapeutics for their efficacy in pre-clinical studies. We also discuss the challenges underlying the use of nanomedicine with a focus on their route of administration, concentration, metabolism, and any toxic effects for successful therapeutics in these diseases.

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

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

Low doses of BPF-induced hypertrophy in cardiomyocytes derived from human embryonic stem cells via disrupting the mitochondrial fission upon the interaction between ERβ and calcineurin A-DRP1 signaling pathway

Bisphenol F (BPF) is a replacement to bisphenol A, which has been extensively used in industrial manufacturing. Its wide detection in various human samples raises increasing concern on its safety. Currently, whether a low dose of BPF compromises cardiac function is still unknown. This study provides the first evidence that low-dose BPF can induce cardiac hypertrophy by using cardiomyocytes derived from human embryonic stem cells (hES). Non-cytotoxic BPF increased cytosolic Ca 2+ influx ([Ca2+ ]c), which was most remarkable at low dose (7 ng/ml) rather than at higher doses. Significant changes in the morphological parameters of mitochondria and significant decreases in ATP production were induced by 7 ng/ml BPF, representing a classic hypertrophic cardiomyocyte. After eliminating the direct effects on mitochondrial fission-related DRP1 by administration of the DRP1 inhibitor Mdivi-1, we examined the changes in [Ca 2+ ]c levels induced by BPF, which enhanced the calcineurin (Cn) activity and induced the abnormal mitochondrial fission via the CnAβ-DRP1 signaling pathway. BPF triggered excessive Ca 2+ influx by disrupting the L-type Ca 2+channel in cardiomyocytes. The interaction between ERβ and CnAβ cooperatively involved in the BPF-induced Ca 2+ influx, which resulted in the abnormal mitochondrial fission and compromised the cardiac function. Our findings provide a feasible molecular mechanism for explaining low-dose BPF-induced cardiac hypertrophy in vitro, preliminarily suggesting that BPF may not be as safe as assumed in humans.

The orphan nuclear receptor Nur77 plays a vital role in BPA-induced PC12 cell apoptosis

Bisphenol A (BPA) is a typical environmental endocrine disruptor that can migrate into organisms through skin contact, breathing, diet and various other approaches. The reproductive toxicity and neurotoxicity of BPA has been confirmed by several toxicological studies. However, the neurotoxicity of BPA is still controversial. In the present study, we used PC12 cells as a model to investigate the mechanism of BPA-induced neuronal apoptosis. BPA exposure reduced cell viability, altered cell morphology and aggravated intracellular Lactate dehydrogenase (LDH) release, intracellular Ca²⁺ concentration, Reactive oxygen species (ROS) levels, apoptosis and the reduction in the mitochondrial transmembrane potential (ΔΨm). Moreover, the results of the Western blot (WB) and Real-time quantitative polymerase chain reaction (RT-qPCR) assays indicated that the expression levels of Nur77 in the BPA group were down-regulated and accompanied by the downregulation of the NF-κb/Bcl-2 proteins and the upregulation of cleaved-caspase 3, which is a marker of apoptosis. However, these changes were significantly reversed with the upregulation of the Nur77 protein by introducing plasmids carrying the nur77 gene. These results indicated that BPA-induced apoptosis was closely related to Nur77-mediated inhibition of the NF-κb/Bcl-2 pathway.

Elucidation of the Effects of Bisphenol A and Structural Analogs on Germ and Steroidogenic Cells Using Single Cell High-Content Imaging

Concerns about the potential adverse effects of bisphenol A (BPA) have led to an increase in the use of replacements, yet the toxicity data for several of these chemicals are limited. Using high-content imaging, we compared the effects of BPA, BPAF, BPF, BPS, BPM, and BPTMC in germ (C18-4 spermatogonial) and steroidogenic (MA-10 Leydig and KGN granulosa) cell lines. Effects on cell viability and phenotypic markers were analyzed to determine benchmark concentrations (BMCs) and estimate administered equivalent doses (AEDs). In all 3 cell lines, BPA was one of the least cytotoxic bisphenol compounds tested, whereas BPM and BPTMC were the most cytotoxic. Interestingly, BPF and BPS were cytotoxic only in MA-10 cells. Effects on phenotypic parameters, including mitochondria, lysosomes, lipid droplets, and oxidative stress, were both bisphenol- and cell-line specific. BPA exposure affected mitochondria (BMC: 1.2 μM; AED: 0.09 mg/kg/day) in C18-4 cells. Lysosome numbers were increased in MA-10 cells exposed to BPA or BPAF but decreased in KGN cells exposed to BPAF or BPM. Lipid droplets were decreased in C18-4 cells exposed to BPF and in MA-10 cells exposed to BPTMC but increased in BPF, BPM, and BPTMC-exposed KGN cells. BPA and BPM exposure induced oxidative stress in MA-10 and KGN cells, respectively. In summary, structurally similar bisphenols displayed clear cell-line-specific differences in BMC and AED values for effects on cell viability and phenotypic endpoints. This approach, together with additional data on human exposure, may aid in the selection and prioritization of responsible replacements for BPA. .

Bisphenol A and rotenone induce S-nitrosylation of protein disulfide isomerase (PDI) and inhibit neurite outgrowth of primary cultured cells of the rat hippocampus and PC12 cells

Bisphenol A (BPA) interferes the function and development of the central nervous system (CNS), resulting in behavioral abnormalities and memory loss. S-nitrosylation of protein disulfide isomerase (PDI) is increased in brains with sporadic Alzheimer's disease and Parkinson's disease. The aim of the present study was to clarify the role of nitric oxide (NO) in BPA-induced neurotoxicity. Since rotenone induces NO-mediated neurodegeneration through S-nitrosylation of PDI, it was used as a positive control. First, rats were treated with BPA and rotenone, and S-nitrosylation of PDI was detected in rat brain microsomes. BPA and rotenone decreased RNase oxidation activity of PDI concomitant with S-nitrosylation of PDI. Next, to clarify S-nitrosylation of PDI by BPA and rotenone in rat brains, we treated the rat pheochromocytoma cell line PC12 and primary cultured neuron cells from the rat hippocampus with BPA (5 and 10 μM) and rotenone (100 or 200 nM). BPA induced S-nitrosylation of PDI, while NG-monomethyl-L-arginine (L-NMMA), a NOS inhibitor, exerted the opposite effects. Finally, to evaluate the toxicity of BPA in the CNS, we investigated its effects on neurite outgrowth of PC12 and primary cultured neuron cells. BPA inhibited neurite outgrowth of these cells, while L-NMMA reversed this inhibition. The involvement of PDI activity in neurite outgrowth was also examined, and bacitracin, a PDI inhibitor, is shown to decrease neurite outgrowth. Furthermore, the overexpression of PDI, but not a catalytically inactive PDI mutant, enhanced neurite outgrowth. These results suggested that S-nitrosylation of PDI induced by excessive NO caused BPA-induced neurotoxicity.

Mitochondrial and Autophagic Regulation of Adult Neurogenesis in the Healthy and Diseased Brain

Adult neurogenesis is a highly regulated process during which new neurons are generated from neural stem cells in two discrete regions of the adult brain: the subventricular zone of the lateral ventricle and the subgranular zone of the dentate gyrus in the hippocampus. Defects of adult hippocampal neurogenesis have been linked to cognitive decline and dysfunction during natural aging and in neurodegenerative diseases, as well as psychological stress-induced mood disorders. Understanding the mechanisms and pathways that regulate adult neurogenesis is crucial to improving preventative measures and therapies for these conditions. Accumulating evidence shows that mitochondria directly regulate various steps and phases of adult neurogenesis. This review summarizes recent findings on how mitochondrial metabolism, dynamics, and reactive oxygen species control several aspects of adult neural stem cell function and their differentiation to newborn neurons. It also discusses the importance of autophagy for adult neurogenesis, and how mitochondrial and autophagic dysfunction may contribute to cognitive defects and stress-induced mood disorders by compromising adult neurogenesis. Finally, I suggest possible ways to target mitochondrial function as a strategy for stem cell-based interventions and treatments for cognitive and mood disorders.

The Impact of Estrogen and Estrogen-Like Molecules in Neurogenesis and Neurodegeneration: Beneficial or Harmful?

Estrogens and estrogen-like molecules can modify the biology of several cell types. Estrogen receptors alpha (ERα) and beta (ERβ) belong to the so-called classical family of estrogen receptors, while the G protein-coupled estrogen receptor 1 (GPER-1) represents a non-classical estrogen receptor mainly located in the plasma membrane. As estrogen receptors are ubiquitously distributed, they can modulate cell proliferation, differentiation, and survival in several tissues and organs, including the central nervous system (CNS). Estrogens can exert neuroprotective roles by acting as anti-oxidants, promoting DNA repair, inducing the expression of growth factors, and modulating cerebral blood flow. Additionally, estrogen-dependent signaling pathways are involved in regulating the balance between proliferation and differentiation of neural stem/progenitor cells (NSPCs), thus influencing neurogenic processes. Since several estrogen-based therapies are used nowadays and estrogen-like molecules, including phytoestrogens and xenoestrogens, are omnipresent in our environment, estrogen-dependent changes in cell biology and tissue homeostasis have gained attention in human health and disease. This article provides a comprehensive literature review on the current knowledge of estrogen and estrogen-like molecules and their impact on cell survival and neurodegeneration, as well as their role in NSPCs proliferation/differentiation balance and neurogenesis.

Palmitate exacerbates bisphenol A toxicity via induction of ER stress and mitochondrial dysfunction

Combined exposure to dietary nutrients and environmental chemicals may elicit significantly different physiological effects than single exposures. Exposure to dietary saturated fats and environmental toxins is a physiologically-significant dual exposure that is particularly associated with lower socioeconomic status, potentially placing these individuals at heightened risk of xenobiotic toxicities. However, no prior studies have examined interactions between specific lipids and environmental xenobiotics in modulating cellular health. Using primary mouse embryonic fibroblasts, we have discovered that prior exposure to the saturated fatty acid, palmitate, exacerbates cellular toxicity associated with the industrial plasticizer, bisphenol A (BPA). Cell death upon BPA exposure following palmitate pre-treatment was greater than that occurring with either exposure alone. Mechanistically, cell death was preceded by increased endoplasmic reticulum stress and loss of mitochondrial membrane potential in palmitate plus BPA exposed cells, leading to increased caspase-3 cleavage and subsequent apoptosis. Interestingly, inclusion of the unsaturated fatty acid, oleate, along with palmitate during the pre-treatment period completely abrogated the ER stress, mitochondrial toxicity, and cell death induced by subsequent exposure to BPA. Thus, our data identify for the first time an important interaction between a fatty acid and an environmental toxin and have implications for developing nutritional interventions to mitigate the deleterious effects of such xenobiotic exposures.

Mitochondrial Protein Import Dysfunction in Pathogenesis of Neurodegenerative Diseases

Mitochondria play an essential role in maintaining energy homeostasis and cellular survival. In the brain, higher ATP production is required by mature neurons for communication. Most of the mitochondrial proteins transcribe in the nucleus and import in mitochondria through different pathways of the mitochondrial protein import machinery. This machinery plays a crucial role in determining mitochondrial morphology and functions through mitochondrial biogenesis. Failure of this machinery and any alterations during mitochondrial biogenesis underlies neurodegeneration resulting in Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), and Parkinson's disease (PD) etc. Current knowledge has revealed the different pathways of mitochondrial protein import machinery such as translocase of the outer mitochondrial membrane complex, the presequence pathway, carrier pathway, β-barrel pathway, and mitochondrial import and assembly machinery etc. In this review, we have discussed the recent studies regarding protein import machinery, beyond the well-known effects of increased oxidative stress and bioenergetics dysfunctions. We have elucidated in detail how these types of machinery help to import and locate the precursor proteins to their specific location inside the mitochondria and play a major role in mitochondrial biogenesis. We further discuss their involvement in mitochondrial dysfunctioning and the induction of toxic aggregates in neurodegenerative diseases like AD and PD. The review supports the importance of import machinery in neuronal functions and its association with toxic aggregated proteins in mitochondrial impairment, suggesting a critical role in fostering and maintaining neurodegeneration and therapeutic response.

Mitochondrial Dynamics: Fission and Fusion in Fate Determination of Mesenchymal Stem Cells

Mesenchymal stem cells (MSCs) are pivotal to tissue homeostasis, repair, and regeneration due to their potential for self-renewal, multilineage differentiation, and immune modulation. Mitochondria are highly dynamic organelles that maintain their morphology via continuous fission and fusion, also known as mitochondrial dynamics. MSCs undergo specific mitochondrial dynamics during proliferation, migration, differentiation, apoptosis, or aging. Emerging evidence suggests that mitochondrial dynamics are key contributors to stem cell fate determination. The coordination of mitochondrial fission and fusion is crucial for cellular function and stress responses, while abnormal fission and/or fusion causes MSC dysfunction. This review focuses on the role of mitochondrial dynamics in MSC commitment under physiological and stress conditions. We highlight mechanistic insights into modulating mitochondrial dynamics and mitochondrial strategies for stem cell-based regenerative medicine. These findings shed light on the contribution of mitochondrial dynamics to MSC fate and MSC-based tissue repair.

Notch pathway up-regulation via curcumin mitigates bisphenol-A (BPA) induced alterations in hippocampal oligodendrogenesis

CNS myelination process involves proliferation and differentiation of oligodendrocyte progenitor cells (OPCs). Defective myelination causes onset of neurological disorders. Bisphenol-A (BPA), a component of plastic items, exerts adverse effects on human health. Our previous studies indicated that BPA impairs neurogenesis and myelination process stimulating cognitive dysfunctions. But, the underlying mechanism(s) of BPA induced de-myelination and probable neuroprotection by curcumin remains elusive. We found that curcumin protected BPA mediated adverse effects on oligosphere growth kinetics. Curcumin significantly improved proliferation and differentiation of OPCs upon BPA exposure both in-vitro and in-vivo. Curcumin enhanced the mRNA expression and protein levels of myelination markers in BPA treated rat hippocampus. Curcumin improved myelination potential via increasing β-III tubulin-/MBP⁺ cells (neuron-oligodendrocyte co-culture) and augmented fluoromyelin intensity and neurofilament/MBP⁺ neurons in vivo. In silico docking studies suggested Notch pathway genes (Notch-1, Hes-1 and Mib-1) as potential targets of BPA and curcumin. Curcumin reversed BPA mediated myelination inhibition via increasing the Notch pathway gene expression. Genetic and pharmacological Notch pathway inhibition by DAPT and Notch-1 siRNA exhibited decreased curcumin mediated neuroprotection. Curcumin improved BPA mediated myelin sheath degeneration and neurobehavioral impairments. Altogether, results suggest that curcumin protected BPA induced de-myelination and behavioural deficits through Notch pathway activation.

Restoring mitochondrial function and normalizing ROS-JNK/MAPK pathway exert key roles in glutamine ameliorating bisphenol A-induced intestinal injury

Bisphenol A (BPA) is toxic to the reproductive and nervous system, even carcinogenetic in humans and animals. However, few studies focused on effects of BPA on the intestinal tract. Here, we detected BPA-induced injuries on intestinal mucosa and explored a reliable approach to counteract BPA effects. C57BL/6J mice were gavage BPA or BPA accompanied with ingestion of 4% (w/w) of glutamine for 4-wks. In vitro, IEC-6 cells were treated with 0.4 mmol/L BPA for 6 hours mimicking acute injury and 0.2 mmol/L BPA for 12 hours followed with or without the inclusion of 4 mmol/L glutamine for 12 hours to determine cell renewal, mitochondrial function and ROS-JNK/MAPK pathway upon moderate BPA exposure. As results, BPA exposure caused severe intestinal injury, and disturbed intestinal epithelial cell proliferation and apoptosis, accompanied with mitochondrial malfunction and activated JNK/MAPK pathway as well. Notably, glutathione metabolism was implicated in BPA-induce injury. Glutamine could well rescue cell renewal and mitochondrial function from BPA exposure-induced injuries. In conclusion, we demonstrated impaired effect of BPA exposure on intestinal functions, which could be well counteracted by glutamine partly via restoring mitochondrial function and normalizing ROS-JNK/MAPK pathway. Thereby, we provided a novel application of glutamine to rescue intestinal injury.

Neuro-toxic and Reproductive Effects of BPA

Background:

Bisphenol A (BPA) is one of the highest volume chemicals produced worldwide. It has recognized activity as an endocrine-disrupting chemical and has suspected roles as a neurological and reproductive toxicant. It interferes in steroid signaling, induces oxidative stress, and affects gene expression epigenetically. Gestational, perinatal and neonatal exposures to BPA affect developmental processes, including brain development and gametogenesis, with consequences on brain functions, behavior, and fertility.

Methods:

This review critically analyzes recent findings on the neuro-toxic and reproductive effects of BPA (and its ana-logues), with focus on neuronal differentiation, synaptic plasticity, glia and microglia activity, cognitive functions, and the central and local control of reproduction.

Results:

BPA has potential human health hazard associated with gestational, peri- and neonatal exposure. Beginning with BPA’s disposition, this review summarizes recent findings on the neurotoxicity of BPA and its analogues, on neuronal dif-ferentiation, synaptic plasticity, neuro-inflammation, neuro-degeneration, and impairment of cognitive abilities. Furthermore, it reports the recent findings on the activity of BPA along the HPG axis, effects on the hypothalamic Gonadotropin Releas-ing Hormone (GnRH), and the associated effects on reproduction in both sexes and successful pregnancy.

Conclusion:

BPA and its analogues impair neuronal activity, HPG axis function, reproduction, and fertility. Contrasting re-sults have emerged in animal models and human. Thus, further studies are needed to better define their safety levels. This re-view offers new insights on these issues with the aim to find the “fil rouge”, if any, that characterize BPA’s mechanism of action with outcomes on neuronal function and reproduction.

Global liver proteomic analysis of Wistar rats chronically exposed to low-levels of bisphenol A and S

Exposure to bisphenol A (BPA) and bisphenol S (BPS) has been associated with the development of metabolic disorders, such as obesity, dyslipidemias, and nonalcoholic fatty liver disease. Nonetheless, the associated mechanisms are still not fully understood. BPS is being used with no restrictions to replace BPA, which increases the concern regarding its safety and claims for further investigation on its potential mechanisms of toxicity. The present study aims to access liver molecular disturbances which could be associated with systemic metabolic disorders following exposure to BPA or BPS. Therefore, body weight gain and serum biochemical parameters were measured in male Wistar rats chronically exposed to 50 or 500 µg/kg/day of BPA or BPS, while an extensive evaluation of liver protein expression changes was conducted after exposure to 50 µg/kg/day of both compounds. Exposure to the lowest dose of BPA led to the development of hyperglycemia and hypercholesterolemia, while the BPS lowest dose led to the development of hypertriglyceridemia. Besides, exposure to 500 µg/kg/day of BPS significantly increased body weight gain and LDL-cholesterol levels. Hepatic proteins differentially expressed in BPA and BPS-exposed groups compared to the control group were mostly related to lipid metabolism and synthesis, with upregulation of glucokinase activity-related sequence 1 (1.8-fold in BPA and 2.4-fold in BPS), which is involved in glycerol triglycerides synthesis, and hydroxymethylglutaryl-CoA synthase cytoplasmic (2-fold in BPS), an enzyme involved in mevalonate biosynthesis. Essential mitochondrial proteins of the electron transport chain were upregulated after exposure to both contaminants. Also, BPA and BPS dysregulated expression of liver antioxidant enzymes, which are involved in cellular reactive oxygen species detoxification. Altogether, the results of the present study contribute to expand the scientific understanding of how BPA and BPS lead to the development of metabolic disorders and reinforce the risks associated with exposure to these contaminants.

Pioglitazone Protects Compression-Mediated Apoptosis in Nucleus Pulposus Mesenchymal Stem Cells by Suppressing Oxidative Stress

Excessive compression, the main cause of intervertebral disc (IVD) degeneration, affected endogenous repair of the intervertebral disc. Pioglitazone (PGZ) is the agonist of peroxisome proliferator-activated receptor γ, which has been widely used in the treatment of diabetes mellitus. The present study aim at investigating whether pioglitazone has protective effects on compression-mediated cell apoptosis in nucleus pulposus mesenchymal stem cells (NP-MSCs) and further exploring the possible underlying mechanism. Our results indicated that the isolated cells satisfied the criteria of MSC stated by the International Society for Cellular Therapy. Besides, our research revealed that pioglitazone could protect cell viability, cell proliferation of NP-MSCs and alleviated the toxic effects caused by compression. The actin stress fibers was suppressed obviously under compression, and pioglitazone alleviated the adverse outcomes. Pioglitazone exerted protective effects on compression-induced NP-MSCs apoptosis according to annexin V/PI double-staining and TUNEL assays. Pioglitazone suppressed compression-induced NP-MSCs oxidative stress, including decreasing compression-induced overproduction of reactive oxygen species (ROS) and malondialdehyde (MDA), and alleviated compression-induced mitochondrial membrane potential (MMP) decrease. Ultrastructure collapse of the mitochondria exhibited a notable improvement by pioglitazone in compression-induced NP-MSCs according to transmission electron microscopy (TEM). Furthermore, the molecular results showed that pioglitazone significantly decreased the expression of apoptosis-associated proteins, including cyto.cytochrome c, Bax, cleaved caspase-9, and cleaved caspase-3, and promoted Bcl-2 expression. These results indicated that pioglitazone alleviated compression-induced NP-MSCs apoptosis by suppressing oxidative stress and the mitochondrial apoptosis pathway, which may be a valuable candidate for the treatment of IVD degeneration.

N-Acetylcysteine Attenuates the Increasing Severity of Distant Organ Liver Dysfunction after Acute Kidney Injury in Rats Exposed to Bisphenol A

Distant organ liver damage after acute kidney injury (AKI) remains a serious clinical setting with high mortality. This undesirable outcome may be due to some hidden factors that can intensify the consequences of AKI. Exposure to bisphenol A (BPA), a universal chemical used in plastics industry, is currently unavoidable and can be harmful to the liver. This study explored whether BPA exposure could be a causative factor that increase severity of remote liver injury after AKI and examined the preventive benefit by N-acetylcysteine (NAC) in this complex condition. Male Wistar rats were given vehicle, BPA, or BPA + NAC for 5 weeks then underwent 45 min renal ischemia followed by 24 h reperfusion (RIR), a group of vehicle-sham-control was also included. RIR not only induced AKI but produced liver injury, triggered systemic oxidative stress as well as inflammation, which increasing severity upon exposure to BPA. Given NAC to BPA-exposed rats diminished the added-on effects of BPA on liver functional impairment, oxidative stress, inflammation, and apoptosis caused by AKI. NAC also mitigated the abnormalities in mitochondrial functions, dynamics, mitophagy, and ultrastructure of the liver by improving the mitochondrial homeostasis regulatory signaling AMPK-PGC-1α-SIRT3. The study demonstrates that NAC is an effective adjunct for preserving mitochondrial homeostasis and reducing remote effects of AKI in environments where BPA exposure is vulnerable.