Nonylphenol induces the death of neural stem cells due to activation of the caspase cascade and regulation of the cell cycle

The impact of endocrine-disrupting chemicals on stem cells: Mechanisms and implications for human health

Endocrine-disrupting chemicals (EDCs) are compounds, either natural or man-made, that interfere with the normal functioning of the endocrine system. There is increasing evidence that exposure to EDCs can have profound adverse effects on reproduction, metabolic disorders, neurological alterations, and increased risk of hormone-dependent cancer. Stem cells (SCs) are integral to these pathological processes, and it is therefore crucial to understand how EDCs may influence SC functionality. This review examines the literature on different types of EDCs and their effects on various types of SCs, including embryonic, adult, and cancer SCs. Possible molecular mechanisms through which EDCs may influence the phenotype of SCs are also evaluated. Finally, the possible implications of these effects on human health are discussed. The available literature demonstrates that EDCs can influence the biology of SCs in a variety of ways, including by altering hormonal pathways, DNA damage, epigenetic changes, reactive oxygen species production and alterations in the gene expression patterns. These disruptions may lead to a variety of cell fates and diseases later in adulthood including increased risk of endocrine disorders, obesity, infertility, reproductive abnormalities, and cancer. Therefore, the review emphasizes the importance of raising broader awareness regarding the intricate impact of EDCs on human health.

Association between prenatal exposure to alkylphenols and intelligence quotient among preschool children: sex-specific effects

BACKGROUND

While prenatal exposure to alkylphenols (APs) has been demonstrated to be associated with neurodevelopmental impairments in animals, the evidence from epidemiological studies remains limited and inconclusive. This study aimed to explore the link between AP exposure during pregnancy and the intelligence quotient (IQ) of preschool children.

METHODS

A total of 221 mother-child pairs from the Guangxi Zhuang Birth Cohort were recruited. Nonylphenol (NP), 4-tert-octylphenol (4-T-OP), 4-n-nonylphenol (4-N-NP), and 4-n-octylphenol were measured in maternal serum in early pregnancy. Childhood IQ was evaluated by the Fourth Edition of Wechsler Preschool and Primary Scale of the Intelligence at 3 to 6 years of age. The impact of APs on childhood IQ were evaluated by generalized linear models (GLMs), restricted cubic spline (RCS), and Bayesian kernel machine regression (BKMR).

RESULTS

In GLMs, prenatal exposure to NP and the second tertile of 4-T-OP exhibited an inverse association with full-scale IQ (FSIQ) (β = -2.38; 95% CI: -4.59, -0.16) and working memory index (WMI) (β = -5.24; 95% CI: -9.58, -0.89), respectively. Prenatal exposure to the third tertile of 4-N-NP showed a positive association with the fluid reasoning index (β = 4.95; 95% CI: 1.14, 8.77) in total children, as well as in girls when stratified by sex. A U-shaped relationship between maternal 4-T-OP and WMI was noted in total children and girls by RCS (all P nonlinear < 0.05). The combined effect primarily driven by NP, of maternal AP mixtures at concentrations above the 50th percentile exhibited an inverse trend on FSIQ in total children and girls in BKMR.

CONCLUSIONS

Prenatal exposure to various APs affects IQ in preschool children, and there may be nonmonotonic and sex-specific effects. Further investigation across the population is required to elucidate the potential neurotoxic effects of APs.

Therapeutic effect of thymoquinone on brain damage caused by nonylphenol exposure in rats

Nonylphenol (NP), causes various harmful effects such as cognitive impairment and neurotoxicity. Thymoquinone (TQ), has antioxidant, anti-inflammatory, and neuroprotective properties. In this study, our aim is to investigate the effects of TQ on the brain damage caused by NP. Corn oil was applied to the control group. NP (100 mg/kg/day) was administered to the NP and NP + TQ groups for 21 days. TQ (5 mg/kg/day) was administered to the NP + TQ and TQ groups for 7 after 21 days. At the end of the experiment, the new object recognition test was applied to the rats and the rats were killed and their brain tissues were removed. Sections taken from brain tissues were stained with hematoxylin-eosin for histopathological evaluation. In addition, neuronal nuclei (NeuN), glial fibrillary acidic protein (GFAP), Cas-3, and nerve growth factor (NGF) immunoreactivities were evaluated in brain tissue sections. In addition, malondialdehyde (MDA), superoxide dismutase (SOD), and catalase (CAT) activities were determined. Comet assay was applied to determine DNA damage in cells. The results of our study showed that NP, caused behavioral disorders and damage to the cerebral cortex in rats. This damage in the form of neuron degeneration seen in the cortex was associated with apoptosis involving Cas-3 activation, increased DNA damage, and free oxygen radicals. NP, SOD, and CAT caused a decrease in enzyme activities. In addition, the cellular protein NeuN was decreased, astrocytosis-associated GFAP was increased, and growth factor NGF was decreased. When all our evaluations are taken together, treatment with TQ showed an ameliorative effect on the behavioral impairment and brain damage caused by NP exposure.

Ecotoxicological impacts caused by high demand surfactants in Latin America and a technological and innovative perspective for their substitution

Nowadays, water pollution represents a great concern due to population growth, industrialization, and urbanization. Every day hazardous chemical products for humans and aquatic organisms are disposed of arbitrarily from homes and industries. Even though detergents are considered an essential market, there is evidence of environmental impacts caused by surfactants like nonylphenol ethoxylate (NPE) and linear alkylbenzene sulfonates (LAS). Regulations about maximum allowable concentrations in sewage, surface water, and drinking water are scarce or null, mostly in developing countries like Latin American countries. Therefore, this review explores these two common toxic surfactants (NPE and LAS) and proposes a technological, innovative, and ecological perspective on detergents. Also, it establishes a starting point for industries to minimize adverse effects on humans and environmental health caused by these compounds.

Thymoquinone Improved Nonylphenol-Induced Memory Deficit and Neurotoxicity Through Its Antioxidant and Neuroprotective Effects

Nonylphenol (NP), a well-known endocrine-disrupter chemical, has several harmful effects on the central nervous system including neuroendocrine disruption, cognitive impairment, and neurotoxicity. Thymoquinone (TQ) is a main bioactive compound in the black seeds of Nigella sativa that has antioxidant, anti-inflammatory, and neuroprotective properties. Here, we investigated the neuroprotective effect of TQ against NP-induced memory deficit and neurotoxicity in rats. To induce memory impairment, NP (25 mg/kg) was used as gavage in male Wistar rats for 21 days. TQ (2.5, 5, and 10 mg/kg) was intraperitoneally administered in NP-treated animals. The morris water maze test was performed to assess spatial learning and memory. The hippocampal tissues were isolated from the brain for histopathological evaluation. Biochemical, molecular, and cellular tests were performed to quantify oxidant (malondialdehyde; MDA)/antioxidant (superoxide dismutase (SOD), total antioxidant capacity (TAC), and reduced glutathione (GSH) parameters) as well as markers for astrocytic activation (glial fibrillary acidic protein; GFAP) and neuronal death (alpha-synuclein; α-syn). Results showed TQ (5 mg/kg) significantly improved NP-induced memory impairment. Histological data revealed a significant increase in the number of necrotic cells in hippocampus, and TQ treatment markedly decreased this effect. The GSH and TAC levels were significantly increased in TQ-treated groups compared to NP group. The molecular analysis indicated that NP increased GFAP and decreased α-syn expression and TQ treatment did the reverse. In vitro study in astrocytes isolated from mice brain showed that TQ significantly increased cell viability in NP-induced cytotoxicity. This study strongly indicates that TQ has neuroprotective effects on NP-induced neurotoxicity through reducing oxidative damages and neuroinflammation. This study investigates the behavioral neurotoxicity induced by Nonylphenol (NP) and the protective effects of Thymoquinone (TQ) as a potent antioxidant compound using molecular, cell culture, histopathological and biochemical techniques.

Selenium improved the combined remediation efficiency of Pseudomonas aeruginosa and ryegrass on cadmium-nonylphenol co-contaminated soil

Most chemical plant wastewater contains both organic and inorganic pollutants, which are easy to diffuse along with surface runoff. The combined pollution of nonylphenol (NP) and cadmium (Cd) in soil is a serious problem that has not attracted enough attention. Based on the effects of selenium (Se) and Pseudomonas aeruginosa (P. aeruginosa) on plant and soil microbial communities, we speculated that the application of Se and P. aeruginosa in soil could improve the phytoremediation efficiency of ryegrass on contaminated soil. In this study, pot experiments with Cd and NP co-contaminated soil were conducted, and the results showed that application of P. aeruinosa alone could improve the removal rates of NP and Cd by ryegrass, and the supplementary of Se further enhanced the effect of micro-phyto remediation, with the highest removal rates of NP and Cd were 79.6% and 49.4%, respectively. The application of P. aeruginosa plus Se reduced the adsorption of Cd and NP through C-O and Si-O-Fe of the soil, changed the enzyme activity, and also affected the changing trend of the microbial community in soil. Pseudomonas, Sphingomonadales, Nitrospira, and other beneficial bacteria were enriched after a 60-day period with P. aeruginosa and Se treatment, thus promoting the removal of NP and Cd. In light of the above results, we suggest that P. aeruginosa application can efficiently facilitate the phytoremediation of ryegrass on Cd-NP co-contaminated soil, and Se supplementation in soil showed the synergistic effect on the remediation.

Behavioral disorders caused by nonylphenol and strategies for protection

Nonylphenol (NP) is widely used in daily production and life due to its good emulsification. In this review, we discuss toxicology studies that examined behavioral disorders caused by NP, the corresponding toxicological mechanisms in the central nervous system (CNS), and strategies for protection. Available in vitro and in vivo evidence suggests that exposure to NP during adulthood or early childhood is associated with cognitive dysfunction, including depression-like behaviors, anxiety-like behaviors, and impaired learning and memory. The main mechanisms underlying NP-related cognitive disorders include inflammation, destruction of synaptic plasticity, and destruction of important signaling pathways that affect the synthesis and secretion of neurotransmitters. The effects and mechanisms of NP exposure on CNS-mediated reproductive function, including interference with the expression of hormones, proteins, and enzymes, are discussed. Other abnormal behaviors such as locomotor activity and swimming behavior are also described. Several measures to prevent NP neurotoxicity are summarized. These measures are based on the toxicological mechanisms underlying NP exposure and include external protection and internal self-regulation of the nervous system. Finally, a new treatment idea is proposed based on the gut-brain axis. Characterizing the behavioral changes and underlying toxicity mechanisms associated with NP exposure and investigating the possible methods of treatment will help to expand the understanding of these mechanisms and could lead to more effective treatments.

The Investigation into Neurotoxicity Mechanisms of Nonylphenol: A Narrative Review

BACKGROUND

Nonylphenol (NP), a chemical compound widely used in industry, is the result of the nonylphenol ethoxylate decomposition and it is known as an estrogen-like compound. Numerous studies and researches have shown that it has many destructive functions of various organs such as the brain. This toxicant causes oxidative stress in the cortex and hippocampus cells, which are two essential regions to preserve memory and learning in the brain.

METHODS

This review examines recent findings to better understanding the mechanisms of NP neurotoxicity. We used Scopus, Google Scholar, and PubMed databases to find articles focused on the destructive effects of NP on the oxidative stress pathway and its defense mechanisms.

RESULTS

NP has potential human health hazards associated with gestational, peri- and postnatal exposure. NP can disrupt brain homeostasis in different ways, such as activation of inflammatory factors in brain especially in hippocampus and cortex, disruption of the cell cycle, changes in neuron, dendrites and synapses morphology, disruption of extra and intracellular calcium ion balance and also memory and learning disorders.

Effects of nonylphenol induced oxidative stress on apoptosis and autophagy in rat ovarian granulosa cells

Nonylphenol (NP) is a kind of environmental endocrine disruptors which is generally recognized to cause female reproductive toxicity, but its basic mechanism has not been fully elucidated. In this study, granulosa cells (GCs) were treated with 0-70 μM NP for 24 h, the cell viability of GCs was reduced significantly, as well as increased cell apoptosis with G2/M arrest. Furthermore, NP significantly induced autophagy and the production of reactive oxygen species (ROS). However, these phenomenons were inhibited by blocking the production of ROS with N-Acetyl-l-cysteine (NAC) administration. Intriguingly, the inhibition of autophagy with 3-Methyladenine (3-MA) could enhance the apoptosis induced by NP. Moreover, the down regulating of p-Akt/Akt, p-mTOR/mTOR and subsequent up-regulation of p-AMPK/AMPK induced by NP can be rescued by pretreatment of NAC. Our findings suggested that NP promotes rat ovarian GCs apoptosis and autophagy simultaneously, which may involve the activation of ROS-dependent Akt/AMPK/mTOR pathway. Whatever, the activation of autophagy is likely to develop a protective mechanism to improve the apoptosis of rat ovarian GCs induced by NP.

Oxidative stress in liver cell culture from mullet, Liza klunzingeri, induced by short-term exposure to benzo[a]pyrene and nonylphenol

The present investigation aimed to use primary liver cell culture obtained from mullet, Liza klunzingeri, to evaluate the toxic effects of benzo[a]pyrene (BaP) and nonylphenol (NP) on the antioxidant defense system. Liver samples taken from 20 L. klunzingeri were digested with 0.1% collagenase IV. The digested cells were then moved to Leibovitz L-15 culture medium and incubated at 25 °C for 2 weeks. 10^-5 mol/l of BaP and 10^-4 mol/l of NP were considered as the half maximal inhibitory concentration (IC50). Cells were then incubated with L-15 medium containing BaP (0[control], 10^-6,2 × 10^-6,3 × 10^-6 mol/l) and NP (0[control],10^-5,2 × 10^-5,3 × 10^-5 mol/l), and sampling was performed after 6, 12, and 24 h of incubation for measurement of catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), lipid peroxidation (LPO), total antioxidant power, and total protein. The lowest concentration of BaP and NP did not have considerable toxic effects on cultivated hepatocytes. The activities of SOD, CAT, GPx, LPO, total antioxidant power, and total protein changed dose-dependently in cells treated with BaP and NP. In conclusion, based on the results, short-term exposure to BaP and NP induced the oxidative stress in cultivated liver cells of L. klunzingeri. The toxicity of both pollutants is mainly because of the induction of the reactive oxygen species (ROS), which lead to cell membrane disruption, damage of cellular metabolism, and interference with cellular macromolecules.

Emerging pollutants (EPs) in Latin América: A critical review of under-studied EPs, case of study -Nonylphenol

Emerging contaminants (EPs) represent a significant risk to human, ecological and environmental health. Although progress has been made in establishing monitoring in environmental matrices, health effects, legislation and control, there are still problems associated with regional bias and the types of EPs commonly assessed, which may underestimate the risk to health. In Latin America there are limited reports on environmental monitoring of EPs and it is generally focused on wastewater. This review identifies the current research deficiencies for emerging contaminants in the Latin American region, and we address the case of nonylphenol as an under-studied EP in the region. Nonylphenol is a degradation product of nonylphenol ethoxylate, which is a surfactant widely used in the manufacture of detergents in Latin America, environmental concentrations have been reported, predominantly in water, and the possible effects on species in this region have been also described. The importance of the review of this compound in the region lies in the fact that the Rotterdam Convention has catalogued nonylphenol as a severely restricted compound, so it is necessary to establish measures for its restriction and change to a sustainable technology. Finally, the example of NP presented in this review highlights the lack of regulation in Latin America regarding to EPs, resulting in the contamination of wastewater, effluents, rivers and drinking water. It is imperative to determine the potential effects, occurrence and concentration levels to improve the regulation of these pollutants in a timely manner.

p-Nonylphenol Impairment of Osteogenic Differentiation of Mesenchymal Stem Cells was Found to be Due to Oxidative Stress and Down-Regulation of RUNX2 and BMP

OBJECTIVES

Previously, it was found that the para-nonylphenol (p-NP) impairs the osteogenic differentiation of rat bone marrow mesenchymal stem cells (rBMSCs); thus the aim of the present study was to evaluate the mechanism of the impairment.

METHODS

rBMSCs after 3rd passage cultured in osteogenic media in the presence of 0, 0.5 and 2.5 μM p-NP for 5, 10, 15 and 20 days. The study investigated the viability of the cells using MTT assays. The mineralization was studied using Alizarin red quantification analysis. Using a flame-photometer, the electrolytes (sodium and potassium) were measured, and the level of calcium as well as ALT, AST, ALP and LDH was determined by commercial kits. The level of total-antioxidant, MDA and the activity of SOD and CAT were estimated with the help of a spectrophotometer. Gene expression was studied using rt-PCR.

RESULTS

The p-NP treatment of osteogenic differentiated MSCs showed intracellular electrolyte imbalance and variation of cellular metabolism. In addition, we observed oxidative stress due to the reduction of total antioxidant capacity and the imbalance of antioxidant enzymes activity. Investigating the genes involved in the osteogenic differentiation of MSCs to osteoblast showed that the 2.5 μM of p-NP reduced the expression of the ALP, SMAD, BMP and RUNX2 genes.

CONCLUSION

The study concludes that this pollutant via influencing the genomics and metabolic imbalance, as well as oxidative induction, caused a reduction of mineralization and differentiation of MSCs. This environmental pollutant might cause osteoporosis, which necessitates raising public awareness, especially to those who live in the industrial area to prevent its drastic effect.

Systems analysis of the liver transcriptome in adult male zebrafish exposed to the non-ionic surfactant nonylphenol

Nonylphenol (NP) arises from the environmental degradation of nonylphenol ethoxylates. It is a ubiquitous environmental contaminant and has been detected at levels up to 167 nM in rivers in the United States. NP is an endocrine disruptor (ED) that can act as an agonist for estrogen receptors. The Adverse Outcome Pathway (AOP) framework defines an adverse outcome as the causal result of a series of molecular initiating events (MIEs) and key events (KEs) that lead to altered phenotypes. This study examined the liver transcriptome after a 21 day exposure to NP and 17β-estradiol (E2) by exploiting the zebrafish (Danio rerio) as a systems toxicology model. The goal of this study was to tease out non-estrogenic genomic signatures associated with NP exposure using DNA microarray and RNA sequencing. Our experimental design included E2 as a positive and potent estrogenic control in order to effectively compare and contrast the 2 compounds. This approach allowed us to identify hepatic transcriptomic perturbations that could serve as MIEs for adverse health outcomes in response to NP. Our results revealed that exposure to NP was associated with differential expression (DE) of genes associated with the development of steatosis, disruption of metabolism, altered immune response, and metabolism of reactive oxygen species, further highlighting NP as a chemical of emerging concern (CEC).

Endocrine Disruption by Mixtures in Topical Consumer Products

Endocrine disruption has been gathering increasing attention in the past 25 years as a possible new threat for health and safety. Exposure to endocrine disruptor has been progressively linked with a growing number of increasing disease in the human population. The mechanics through which endocrine disruptors act are not yet completely clear, however a number of pathways have been identified. A key concern is the cumulative and synergic effects that endocrine disruptors could have when mixed in consumer products. We reviewed the available literature to identify known or potential endocrine disruptors, as well as endocrine active substances that could contribute to cumulative effects, in topical consumer products. The number of endocrine actives used daily in consumer products is staggering and even though most if not all are used in concentrations that are considered to be safe, we believe that the possibility of combined effects in mixtures and non-monotonic dose/response is enough to require further precautions. A combined in vitro approach based on existing, validated OECD test methods is suggested to screen consumer products and mixtures for potential interaction with estrogen and androgen hormone receptors, in order to identify products that could have cumulative effects or support their safety concerning direct endocrine disruption capabilities.

Endocrine-disrupting metabolites of alkylphenol ethoxylates - A critical review of analytical methods, environmental occurrences, toxicity, and regulation

Despite the fact that metabolites of alkylphenol ethoxylates (APEO) are classified as hazardous substances, they continue to be released into the environment from a variety of sources and are not usually monitored. Their wide use has led to an increase in the possible exposure pathways for humans, which is cause for alarm. Moreover, there is a lack of knowledge about the behaviour of these metabolites with respect to the environment and toxicity, and their biological effects on human health. The aim of this work is to give an overview of the APEO metabolites and their analysis, occurrences and toxicity in various environmental and human samples. APEO metabolites have adverse effects on humans, wildlife, and the environment through their release into the environment. Currently, there are some reviews available on the behaviour of alkylphenols in soil, sediments, groundwater, surface water and food. However, none of these articles consider their toxicity in humans and especially their effect on the nervous and immune system. This work summarises the environmental occurrences of metabolites of APEOs in matrices, e.g. water, food and biological matrices, their effect on the immune and nervous systems, and isomer-specific issues. With that emphasis we are able to cover most common occurrences of human exposure, whether direct or indirect.

Bisphenol-A and Nonylphenol Induce Apoptosis in Reproductive Tract Cancer Cell Lines by the Activation of ADAM17

Endocrine-disruptor chemicals (EDCs), such as bisphenol A (BPA) and nonylphenol (NP), have been widely studied due to their negative effects on human and wildlife reproduction. Exposure to BPA or NP is related to cell death, hormonal deregulation, and cancer onset. Our previous studies showed that both compounds induce A Disintegrin And Metalloprotease 17 (ADAM17) activation. Here, we show that BPA and NP induce apoptosis in prostate and ovary cancer cell lines, in a process dependent on ADAM17 activation. ADAM17 knockdown completely prevented apoptosis as well as the shedding of ADAM17 substrates. Both compounds were found to induce an increase in intracellular calcium (Ca²⁺) only in Ca²⁺-containing medium, with the NP-treated cells response being more robust than those treated with BPA. Additionally, using a phosphorylated protein microarray, we found that both compounds stimulate common intracellular pathways related to cell growth, differentiation, survival, and apoptosis. These results suggest that BPA and NP could induce apoptosis through ADAM17 by activating different intracellular signaling pathways that may converge in different cellular responses, one of which is apoptosis. These results confirm the capacity of these compounds to induce cell apoptosis in cancer cell lines and uncover ADAM17 as a key regulator of this process in response to EDCs.

Toxicological assessment of multi-walled carbon nanotubes combined with nonylphenol in male mice

Carbon nanotubes have attracted increasing attention attributable to their widespread application. To evaluate the joint toxicity of multi-walled carbon nanotubes (MWCNTs) and nonylphenol (NP), we investigated the toxicological effects of NP, pristine MWCNTs, and MWCNTs combined with NP in male mice. After exposing male mice by gavage for 5 days, intracellular superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activity, as well as malondialdehyde (MDA) and glutathione (GSH) levels in tissues were determined to evaluate in vivo oxidative stress. In addition, genotoxicity was assessed by examining DNA damage in mouse liver and sperm via the comet assay, and transmission electron microscopy (TEM) was used for direct visual observations of mitochondrial damage in the liver. Results from the oxidative damage and DNA damage experiments indicate that after adsorbing NP, MWCNTs at a high dose induce oxidative lesions in the liver and cause DNA damage in mouse sperm; these data offer new insights regarding the toxicological assessment of MWCNTs.

Exposure to bisphenol A affects GABAergic neuron differentiation in neurosphere cultures

Endocrine-disrupting chemicals (EDCs) influence not only endocrine functions but also neuronal development and functions. In-vivo studies have suggested the relationship of EDC-induced neurobehavioral disorders with dysfunctions of neurotransmitter mechanisms including γ-aminobutyric acid (GABA)ergic mechanisms. However, whether EDCs affect GABAergic neuron differentiation remains unclear. In the present study, we show that a representative EDC, bisphenol A (BPA), affects GABAergic neuron differentiation. Cortical neurospheres prepared from embryonic mice were exposed to BPA for 7 days, and then neuronal differentiation was induced. We found that BPA exposure resulted in a decrease in the ratio of GABAergic neurons to total neurons. However, the same exposure stimulated the differentiation of neurons expressing calbindin, a calcium-binding protein observed in a subpopulation of GABAergic neurons. These findings suggested that BPA might influence the formation of an inhibitory neuronal network in developing cerebral cortex involved in the occurrence of neurobehavioral disorders.

Reproductive effects of cadmium on sperm function and early embryonic development in vitro

Cadmium is a major environmental toxicant that is released into the atmosphere, water and soil in the form of cadmium oxide, cadmium chloride, or cadmium sulfide via industrial activities, such as the manufacturing of batteries and pigments, metal smelting and refining and municipal waste incineration. In the present study, we investigated the effects of cadmium exposure on sperm quality parameters, fertilization capacity and early embryonic development. Our study showed that in vitro incubation of human or mouse sperms with cadmium for a long time (up to 24 hours) could significantly decreased sperm motility in a concentration- and time-dependent manner. Exposure to cadmium in the environment for a short term (30 min) did not affect sperm motility but significantly reduced in vitro fertilization rate. We also evaluated the effects of cadmium at concentrations of 0.625 μg/ml, and 1.25 μg/ml on early embryonic development in vitro and observed that the blastocyst formation rate dramatically decreased with increasing cadmium concentration. This finding emphasizes the hazardous effects of cadmium on sperm quality as well as on natural embryo development and raises greater concerns regarding cadmium pollution.

Using a liver cell culture from Epinephelus coioides as a model to evaluate the nonylphenol-induced oxidative stress

The present study aimed to use primary liver cell culture derived from the orange-spotted grouper, Epinephelus coioides, to assess the toxic effects of nonylphenol (NP) on the hepatocyte viability and the liver antioxidant system. E. coioides was selected due to its commercial importance. NP was used in this study because of its high potential of producing oxidative stress due to increased reactive oxygen species (ROS). A liver of E. coioides was digested with PBS containing 0.1% collagenase IV. The digested cells were moved to Leibovitz L-15 culture medium with 20% fetal bovine serum (FBS), 100IUmL^-1 penicillin, 100μgmL^-1 streptomycin. Aliquots of cell suspension were seeded as a monolayer into sterile 25cm² tissue culture flasks and incubated at 30°C for 14days. The medium, containing non-attached cells, was removed after 24 to 48h and a new medium was added. The IC50 of 10^-4molL^-1 was determined for nonylphenol using MTT assay. Cells were then incubated with L-15 medium containing 10^-5, 2×10^-5, 3×10^-5molL^-1 of NP and samples were taken after 6, 12 and 24h of incubation for analysis of LPO, SOD, CAT, GPx, LDH, AST, ALT, and ALP. Based on the results, the lowest concentration of NP was not markedly cytotoxic to primary hepatocytes and the cell sensitivity to NP increased dose-dependently. The activities of SOD, CAT and GPx decreased significantly, while activities of LPO, LDH, AST, ALT and ALP, increased significantly in a dose-related pattern in NP-treated cells. In conclusion, this study revealed that NP could induce the oxidative stress in cultivated hepatocytes of E. coioides during a short-term exposure. NP toxicity is mainly due to the induction of the reactive oxygen species (ROS), which lead to cell membrane disruption, damage of cellular metabolism, and interference with cellular macromolecules.

An Isomer-Specific Approach to Endocrine-Disrupting Nonylphenol in Infant Food

Nonylphenols (NPs) are persistent endocrine disruptors that are priority hazardous substances of the European Union Water Framework Directive. Their presence in the environment has caused growing concern regarding their impact on human health. Recent studies have shown that nonylphenol is ubiquitous in commercially available foodstuffs and is also present in human blood. The isomer distribution of 4-nonylphenol was analyzed by gas chromatography - mass spectrometry in 44 samples of infant food. Our study shows that the distribution of nonylphenol isomers is dependent on the foodstuff analyzed. Although some isomer groups prevail, different distributions are frequent. Variations are even found in the same food group. Nonylphenol is a complex mixture of isomers, and the estrogenic potentials of each of these isomers are very different. Consequently, to determine the potential toxicological impact of NP in food, an isomer-specific approach is necessary.

Effects of Mono-(2-Ethylhexyl) Phthalate and Di-(2-Ethylhexyl) Phthalate Administrations on Oocyte Meiotic Maturation, Apoptosis and Gene Quantification in Mouse Model

Objective

Phthalates, which are commonly used to render plastics into soft and flexible materials, have also been determined as developmental and reproductive toxicants in human and animals. The purpose of this study was to evaluate the effect of mono-(2- ethylhexyl) phthalate (MEHP) and di-(2-ethylhexyl) phthalate (DEHP) oral administrations on maturation of mouse oocytes, apoptosis and gene transcription levels.

Materials and Methods

In this experimental study, immature oocytes recovered from Naval Medical Research Institute (NMRI) mouse strain (6-8 weeks), were divided into seven different experimental and control groups. Control group oocytes were retrieved from mice that received only normal saline. The experimental groups I, II or III oocytes were retrieved from mice treated with 50, 100 or 200 µl DEHP (2.56 µM) solution, respectively. The experimental groups IV, V or VI oocytes were retrieved from mouse exposed to 50, 100 or 200 µl MEHP (2.56 µM) solution, respectively. Fertilization and embryonic development were carried out in OMM and T6 medium. Apoptosis was assessed by annexin V-FITC/Dead Cell Apoptosis Kit, with PI staining. In addition, the mRNA levels of Pou5f1, Ccna1 and Asah1 were examined in oocytes. Finally, mouse embryo at early blastocyst stage was stained with acridine-orange (AO) and ethidium-bromide (EB), in order to access their viability.

Results

The proportion of oocytes that progressed up to metaphase II (MII) and 2-cells embryo formation stage was significantly decreased by exposure to MEHP or DEHP, in a dose-dependent manner. Annexin V and PI positive oocytes showed greater quantity in the treated mice than control. Quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) revealed that expression levels of Pou5f1, Asah1 and Ccna1 were significantly lower in the treated mouse oocytes than control. The total cell count for blastocyst developed from the treated mouse oocytes was lower than the controls.

Conclusion

These results indicate that oral administration of MEHP and DEHP could negatively affect mouse oocyte meiotic maturation and development in vivo, suggesting that phthalates could be risk factors for mammalians’ reproductive health. Additionally, phthalate-induced changes in Pou5f1, Asah1 and Ccna1 transcription level could explain in part, the reduced developmental ability of mouse-treated oocytes.

Transcription factor activity of estrogen receptor α activation upon nonylphenol or bisphenol A treatment enhances the in vitro proliferation, invasion, and migration of neuroblastoma cells

Many kinds of endocrine-disrupting chemicals (EDCs), for example, the environmental estrogens bisphenol A and nonylphenol, may regulate the activity of estrogen receptor α (ERα) and therefore induce potential disruption of normal endocrine function. However, the involvement of EDCs in human cancers, especially in endocrine-related cancer neuroblastoma regulation, is not very clear. In this work, results showed that upon bisphenol A or nonylphenol treatment, the transcription factor activity of ERα was significantly increased in neuroblastoma cell line SH-SY5Y. Bisphenol A and nonylphenol could enhance ERα activity via recruiting it to the target gene promoter. Furthermore, treatment of bisphenol A and nonylphenol enhanced the in vitro proliferation, invasion, and migration ability of neuroblastoma cells. By investigating the role of EDC-induced ERα upregulation, our data extend the understanding of the function of EDCs and further suggest that ERα might be a potential therapeutic target in human neuroblastoma treatment.

RXRα, PXR and CAR xenobiotic receptors mediate the apoptotic and neurotoxic actions of nonylphenol in mouse hippocampal cells

In the present study, we investigated the role of the retinoid X receptor (RXR), the pregnane X receptor (PXR) and the constitutive androstane receptor (CAR), in the apoptotic and toxic effects of nonylphenol in mouse primary neuronal cell cultures. Our study demonstrated that nonylphenol activated caspase-3 and induced lactate dehydrogenase (LDH) release in hippocampal cells, which was accompanied by an increase in the mRNA expression and protein levels of RXRα, PXR and CAR. Nonylphenol stimulated Rxra, Pxr, and Car mRNA expression. These effects were followed by increase in the protein levels of particular receptors. Immunofluorescence labeling revealed the cellular distribution of RXRα, PXR and CAR in hippocampal neurons in response to nonylphenol, shortening of neurites and cytoplasmic shrinking, as indicated by MAP2 staining. It also showed NP-induced translocation of receptor-specific immunofluorescence from cytoplasm to the nucleus. The use of specific siRNAs demonstrated that Rxra-, Pxr-, and Car-siRNA-transfected cells were less vulnerable to nonylphenol-induced activation of caspase-3 and LDH, thus confirming the key involvement of RXRα/PXR/CAR signaling pathways in the apoptotic and neurotoxic actions of nonylphenol. These new data give prospects for the targeting xenobiotic nuclear receptors to protect the developing nervous system against endocrine disrupting chemicals.

4-Nonylphenol induces apoptosis, autophagy and necrosis in Sertoli cells: Involvement of ROS-mediated AMPK/AKT-mTOR and JNK pathways

The xenoestrogen 4-nonylphenol (NP) induces reproductive dysfunction of male rats, but the fundamental mechanism of this phenomenon is largely unexplored. Sertoli cells (SCs) are pivotal for spermatogenesis and male fertility. The involvement of autophagy in NP-induced apoptotic and necrotic death of SCs was investigated. In this study, 24-h exposure of SCs to 20-30μM NP decreased cell viability, caused G2/M arrest, triggered ΔΨm loss, increased ROS production and induced caspase-dependent apoptosis, necrosis as well as autophagosome formation. NP-induced autophagy was confirmed by monodansylcadaverine-staining and LC3-I/LC3-II conversion. Furthermore, NP up-regulated the (Thr172)p-AMPK/AMPK and (Thr183/185)p-JNK/JNK ratios. This was followed by the down-regulation of (Ser473)p-Akt/Akt, (Thr1462)p-TSC2/TSC2, (Ser2448)p-mTOR/mTOR, (Thr389)p-p70S6K/p70S6K and (Thr37/45)p-4EBP1/4EBP1. Intriguingly, NP-induced apoptosis, autophagy and necrosis could be inhibited through blocking ROS generation by N-acetylcysteine. Autophagy inhibitor 3-MA enhanced NP-induced apoptosis and necrosis. Moreover, The activation of AMPK/mTOR/p70s6k/4EBP1 and JNK signalling pathways induced by NP could be efficiently reversed by pretreatment of N-acetylcysteine or 3-MA. Collectively, our findings provide the first evidence that NP promotes apoptosis, autophagy and necrosis simultaneously in SCs and that this process may involve ROS-dependent JNK- and Akt/AMPK/mTOR pathways. Modulation of autophagy induced by NP may serve as a survival mechanism against apoptosis and necrosis.

Apoptotic and neurotoxic actions of 4-para-nonylphenol are accompanied by activation of retinoid X receptor and impairment of classical estrogen receptor signaling

4-para-Nonylphenol (NP) is a non-ionic surfactant that has widespread and uncontrolled distribution in the environment. Little is known, however, about its actions on neuronal cells during critical developmental periods. This study aimed to investigate the mechanisms underlying the apoptotic and toxic actions of NP on mouse embryonic neuronal cells and the possible interactions of NP with estrogen receptor (ER)- and retinoid X receptor (RXR)-mediated intracellular signaling. Treatment of mouse hippocampal neuronal cell cultures with NP (5 and 10μM) induced apoptotic and neurotoxic effects. The 2 and 7 day-old mouse hippocampal cultures were vulnerable to 5 and 10μM NP, whereas 12 day-old cultures responded only to the highest concentration of NP, thus suggesting an age-dependent action of the chemical on neuronal cells. The use of specific inhibitors did not support the involvement of calpains in NP-induced apoptosis, but indicated caspase-8- and caspase-9-dependent effects of NP. Specific ER antagonists MPP and PHTPP potentiated the NP-induced loss of mitochondrial membrane potential and increase in lactate dehydrogenase (LDH) release whereas, ER agonists PPT and DPN inhibited these effects. RXR antagonist HX531 diminished the NP-evoked loss of mitochondrial membrane potential, the activity of caspase-3 and LDH release. In addition, exposure to NP inhibited ERα- and ERβ-specific immunofluorescence but stimulated RXR-specific immunolabeling in mouse hippocampal cells. In conclusion, our study demonstrated that the apoptotic and toxic actions of NP on neuronal cells in early development is accompanied by an impairment of ER- and stimulation of RXR-mediated signaling pathways. Taking into account NP-induced alterations in mRNA expression levels of particular types of RXRs, we suggest that NP affected mainly RXRα and RXRβ, but not RXRγ signaling.

Actions of endocrine-disrupting chemicals on stem/progenitor cells during development and disease

Development and fate of the stem cell are regulated by extrinsic signals from the environment. Endocrine-disrupting chemicals which perturb hormonal signaling in utero and during early childhood may cause deregulation of multiple developmental processes, ranging from breakdown of stem cell niche architecture, developmental reprograming and altered stem cell fate to impaired organ and gonad development and sexual differentiation. Therefore, study of the environmental effects on stem cell integrity and normal development is a new and emerging focus for developmental biologists and cell toxicologists. When combined with new human and mouse stem cell-based models, stem cell differentiation dynamics can be studied in more biologically relevant ways. In this study, we review the current status of our understanding of the molecular mechanisms by which endocrine disruptors alter embryonic stem cell and adult stem/progenitor cell fate, organ development, cancer stem cell activity, and tumorigenesis.

National inventory of alkylphenol ethoxylate compounds in U.S. sewage sludges and chemical fate in outdoor soil mesocosms

We determined the first nationwide inventories of alkylphenol surfactants in U.S. sewage sludges (SS) using samples from the U.S. Environmental Protection Agency's 2001 national SS survey. Additionally, analysis of archived 3-year outdoor mesocosm samples served to determine chemical fates in SS-amended soil. Nonylphenol (NP) was the most abundant analyte (534 ± 192 mg/kg) in SS composites, followed by its mono- and di-ethoxylates (62.1 ± 28 and 59.5 ± 52 mg/kg, respectively). The mean annual load of NP and its ethoxylates in SS was estimated at 2408-7149 metric tonnes, of which 1204-4289 is applied on U.S. land. NP compounds showed observable loss from SS/soil mixtures (1:2), with mean half-lives ranging from 301 to 495 days. Surfactant levels in U.S. SS ten-times in excess of European regulations, substantial releases to U.S. soils, and prolonged half-lives found under field conditions, all argue for the U.S. to follow Europe's move from 20 years ago to regulate these chemicals.

The effects of Di-(2-ethylhexyl)-phthalate exposure on fertilization and embryonic development in vitro and testicular genomic mutation in vivo

The present study was undertaken to determine the reproductive hazards of Di-(2-ethylhexyl)-phthalate (DEHP) on mouse spermatozoa and embryos in vitro and genomic changes in vivo. Direct low-level DEHP exposure (1 μg/ml) on spermatozoa and embryos was investigated by in vitro fertilization (IVF) process, culture of preimplanted embryos in DEHP-supplemented medium and embryo transfer to achieve full term development. Big Blue® transgenic mouse model was employed to evaluate the mutagenesis of testicular genome with in vivo exposure concentration of DEHP (500 mg/kg/day). Generally, DEHP-treated spermatozoa (1 μg/ml, 30 min) presented reduced fertilization ability (P<0.05) and the resultant embryos had decreased developmental potential compared to DMSO controls (P<0.05). Meanwhile, the transferred 2-cell stage embryos derived from treated spermatozoa also exhibited decreased birth rate than that of control (P<0.05). When fertilized oocytes or 2-cell stage embryos were recovered by in vivo fertilization (without treatment) and then exposed to DEHP, the subsequent development proceed to blastocysts was different, fertilized oocytes were significantly affected (P<0.05) whereas developmental progression of 2-cell stage embryos was similar to controls (P>0.05). Testes of the Big Blue® transgenic mice treated with DEHP for 4 weeks indicated an approximately 3-fold increase in genomic DNA mutation frequency compared with controls (P<0.05). These findings unveiled the hazardous effects of direct low-level exposure of DEHP on spermatozoa's fertilization ability as well as embryonic development, and proved that in vivo DEHP exposure posed mutagenic risks in the reproductive organ – at least in testes, are of great concern to human male reproductive health.

Effect of di-(2-ethylhexyl) phthalate and mono-(2-ethylhexyl) phthalate on in vitro developmental competence of bovine oocytes

In the last decade, potential exposure of humans and animals to industrial chemicals and pesticides has been a growing concern. In the present study, di-(2-ethylhexyl) phthalate (DEHP) and mono-(2-ethylhexyl) phthalate (MEHP) were used to model the effects of endocrine-disrupting compounds and their risk in relation to early embryonic losses. Exposure of cumulus oocyte complexes during maturation to 50 μM MEHP reduced the proportion of oocytes that underwent nuclear maturation (p < 0.05) and increased the proportion of apoptotic oocytes (p < 0.05). Furthermore, phthalates reduced cleavage rate in the MEHP-treated group (p < 0.05) and the proportion of embryos developing to the blastocyst stage in both DEHP- and MEHP-treated groups (p < 0.05). The total cell count for blastocysts developing from MEHP-treated oocytes was lower than in controls (p < 0.05). Exposure of oocytes to MEHP during maturation reduced (p < 0.05) the expression of ASAH1 (an anti-apoptotic factor), CCNA2 (involved in cell cycle control), and POU5F1 (responsible for pluripotency) in matured oocytes. Furthermore, the reduced mRNA expression of POU5F1 and ASAH1 lasted into two-cell stage embryos (p < 0.05). Phthalate-induced alterations in POU5F1, ASAH1, and CCNA2 expression might explain in part the reduced developmental competence of MEHP-treated oocytes.

Mechanisms of neurotoxicity induced in the developing brain of mice and rats by DNA-damaging chemicals

It is not widely known how the developing brain responds to extrinsic damage, although the developing brain is considered to be sensitive to diverse environmental factors including DNA-damaging agents. This paper reviews the mechanisms of neurotoxicity induced in the developing brain of mice and rats by six chemicals (ethylnitrosourea, hydroxyurea, 5-azacytidine, cytosine arabinoside, 6-mercaptopurine and etoposide), which cause DNA damage in different ways, especially from the viewpoints of apoptosis and cell cycle arrest in neural progenitor cells. In addition, this paper also reviews the repair process following damage in the developing brain.

Effects of 4-nonylphenol on proliferation of AGS gastric cells

OBJECTIVES

Nonylphenol (NP) is present ubiquitously in both aquatic and terrestrial environments. This compound is considered an important endocrine disruptor and its toxic/oestrogenic activity has been investigated in a number of in vitro and in vivo studies. Human exposure to NP may occur by cutaneous absorption, ingestion of contaminated food or water and inhalation. Moreover, while the cytotoxic effects of NP are known and studied, its effects on cell death and related mechanisms are not known. Our group decided to investigate NP effects on a gastric epithelial cell line (AGS), in particular NP effects on AGS cell cycle and apoptosis.

MATERIALS AND METHODS

Cell cycle was analysed by flow cytometry, p21 and p27 induction, and apoptosis was analysed by flow cytometry and annexin-V assays, Fas, Fas-L, caspase 8 and caspase 3 activation.

RESULTS

We have demonstrated that NP affected cell cycle and apoptosis in a time- and dose-dependent manner, reaching the most notable effect at concentration of 10(-7)m, for 48 h. Flow cytometry revealed that treatment with 10(-7) m NP led to accumulation of cells at G(2) /M transition and increased percentage population of apoptotic cells. Results have shown that NP at concentration 10(-7) m induced marked increase in Fas and Fas-L expression. Moreover, 10(7) m NP induced activation of caspases 8 and 3, but not activation of caspase 9.

CONCLUSIONS

The results reported suggest that gastric cells can be useful as screening population for appropriate study of developmental toxicity.

Stem cell-derived in vitro models for investigating the effects of endocrine disruptors on developing neurons and neuroendocrine cells

Neuroendocrine cells are a set of specialized hormone-releasing neurons that control most vital functions in humans and wildlife, such as growth, reproduction, metabolism, and stress responses. Increasing evidence points to neuroendocrine cells as the primary neuronal target of endocrine disruptors. Endocrine disruption appears to be most significant during prenatal and early postnatal development. However, limitations with traditional cell culture models of neuronal development led to a lack of understanding regarding the mechanisms by which endocrine disruptors affect neurodevelopment. In recent years, Stem Cell-derived neuronal models have become available and may offer distinct advantages over other in vitro model systems for investigating the effects of endocrine disruptors on the developing brain. Further, recently new models of Stem Cell-derived neuroendocrine cells that may provide more effective ways for studying the effects of endocrine disruptors directly on developing neuroendocrine cells in vitro were developed. This constitutes a review of currently available cell models of developing neurons that have been used to investigate in vitro effects of endocrine disruptors on developing brain. The review also presents recently developed models of Stem Cell-derived neuroendocrine cells that might be used to investigate in vitro effects of endocrine disruptors and their mechanisms of action directly on the developing neuroendocrine cells.

Effects of estrogens and endocrine-disrupting chemicals on cell differentiation-survival-proliferation in brain: contributions of neuronal cell lines

Estrogens and estrogen receptors (ER) are key actors in the control of differentiation and survival and act on extrareproductive tissues such as brain. Thus, estrogens may display neuritogenic effects during development and neuroprotective effects in the pathophysiological context of brain ischemia and neurodegenerative pathologies like Alzheimer's disease or Parkinson's disease. Some of these effects require classical transcriptional "genomic" mechanisms through ER, whereas other effects appear to rely clearly on "membrane-initiated mechanisms" through cytoplasmic signal transduction pathways. Disturbances of these mechanisms by endocrine-disrupting chemicals (EDC) may exert adverse effects on brain. Some EDC may act via ER-independent mechanisms but might cross-react with endogenous estrogen. Other EDC may act through ER-dependent mechanisms and display agonistic/antagonistic estrogenic properties. Because of these potential effects of EDC, it is necessary to establish sensitive cell-based assays to determine EDC effects on brain. In the present review, some effects of estrogens and EDC are described with focus on ER-mediated effects in neuronal cells. Particular attention is given to PC12 cells, an interesting model to study the mechanisms underlying ER-mediated differentiating and neuroprotective effects of estrogens.

Estrogen stimulates proliferation and differentiation of neural stem/progenitor cells through different signal transduction pathways

Our previous study indicated that both 17β-estradiol (E2), known to be an endogenous estrogen, and bisphenol A (BPA), known to be a xenoestrogen, could positively influence the proliferation or differentiation of neural stem/progenitor cells (NS/PCs). The aim of the present study was to identify the signal transduction pathways for estrogenic activities promoting proliferation and differentiation of NS/PCs via well known nuclear estrogen receptors (ERs) or putative membrane-associated ERs. NS/PCs were cultured from the telencephalon of 15-day-old rat embryos. In order to confirm the involvement of nuclear ERs for estrogenic activities, their specific antagonist, ICI-182,780, was used. The presence of putative membrane-associated ER was functionally examined as to whether E2 can activate rapid intracellular signaling mechanism. In order to confirm the involvement of membrane-associated ERs for estrogenic activities, a cell-impermeable E2, bovine serum albumin-conjugated E2 (E2-BSA) was used. We showed that E2 could rapidly activate extracellular signal-regulated kinases 1/2 (ERK 1/2), which was not inhibited by ICI-182,780. ICI-182,780 abrogated the stimulatory effect of these estrogens (E2 and BPA) on the proliferation of NS/PCs, but not their effect on the differentiation of the NS/PCs into oligodendroglia. Furthermore, E2-BSA mimicked the activity of differentiation from NS/PCs into oligodendroglia, but not the activity of proliferation. Our study suggests that (1) the estrogen induced proliferation of NS/PCs is mediated via nuclear ERs; (2) the oligodendroglial generation from NS/PCs is likely to be stimulated via putative membrane-associated ERs.

Differential cytotoxic effects of mono-(2-ethylhexyl) phthalate on blastomere-derived embryonic stem cells and differentiating neurons

Potential applications of embryonic stem (ES) cells are not limited to regenerative medicine but can also include in vitro screening of various toxicants. In this study, we established mouse ES cell lines from isolated blastomeres of two-cell stage embryos and examined their potential use as an in vitro system for the study of developmental toxicity. Two ES cell lines were established from 69 blastomere-derived blastocysts (2.9%). The blastomere-derived ES (bm-ES) cells were treated with mono-(2-ethylhexyl) phthalate (MEHP) in an undifferentiated state or after directed differentiation into early neural cell types. We observed significantly decreased cell viability when undifferentiated bm-ES cells were exposed to a high dose of MEHP (1000 microM). The cytotoxic effects of MEHP were accompanied by increased DNA fragmentation, nuclear condensation, and activation of Caspase-3, which are biochemical and morphological features of apoptosis. Compared to undifferentiated bm-ES cells, considerably lower doses of MEHP (50 and 100 microM) were sufficient to induce cell death in early neurons differentiated from bm-ES cells. At the lower doses, the number of neural cells positive for the active form of Caspase-3 was greater than that for undifferentiated bm-ES cells. Thus, our data indicate that differentiating neurons are more sensitive to MEHP than undifferentiated ES cells, and that undifferentiated ES cells may have more efficient defense systems against cytotoxic stresses. These findings might contribute to the development of a new predictive screening method for assessment of hazards for developmental toxicity.

PPARgamma-mediated advanced glycation end products regulation of neural stem cells

Hyperglycemia is accompanied by an accelerated rate of advanced glycation end products (AGEs) formation, which is found to be associated with the pathogenesis of diabetic cognitive deficit, including Alzheimer's disease (AD). Peroxisome proliferator-activated receptor gamma (PPARgamma) plays an important role in controlling the proliferation of neural stem cells (NSCs) and their neuronal differentiation. We investigate the hypothesis that PPARgamma could mediate AGEs-related regulation of NSCs, by which AGEs possibly fulfill important roles in diabetic-related cognitive impairment. We found that AGEs down-regulated the proliferation and neurogenic differentiation of NSCs, and protein level of PPARgamma. PPARgamma agonist reversed the proliferation through the aid of AGE-BSA, with the exclusion of the neuronal differentiation of the NSCs which were also downregulated by AGE-BSA. These findings extend our understanding of the central role of PPARgamma in AGEs-related neurogenesis impairment, which probably increased risks of cognitive deficits or AD in diabetic patients.

Potencies of bisphenol A on the neuronal differentiation and hippocampal neurogenesis

Endocrine-disrupting chemicals (EDC) produce adverse effects on reproductive and immune function or neurological behavior, and may also induce cancer. The environmental EDC bisphenol A (BPA) is widely used in the manufacture of plastics and epoxy resins. BPA affects reproductive organ growth and development, but the potential adverse effects of BPA on neuronal development are not fully understood. Here, BPA concentration-dependently decreased proliferation of murine-derived multipotent neural progenitor cells (NPC), and high concentrations produced cytotoxicity. In contrast, low concentrations of BPA, which possess estrogenic activity, stimulated NPC differentiation into a neuronal phenotype. BPA treatment did not affect neonatal brain development in F1 mice. However, BPA treatment (20 mg/kg) accelerated formation of the dentate gyrus in postnatal day 1 mice. Prenatal and postnatal BPA treatment did not affect adult hippocampal neurogenesis in the dentate gyrus in 8-wk-old mice. Data indicate that BPA stimulates neuronal differentiation and might disrupt neonatal brain development.