Di(2-ethylhexyl) phthalate-induced apoptosis in rat INS-1 cells is dependent on activation of endoplasmic reticulum stress and suppression of antioxidant protection

Maslinic acid supplementation prevents di(2-ethylhexyl) phthalate-induced apoptosis via PRDX6 in peritubular myoid cells of Chinese forest musk deer

Chinese forest musk deer (FMD), an endangered species, have exhibited low reproductive rates even in captivity due to stress conditions. Investigation revealed the presence of di(2-ethylhexyl) phthalate (DEHP), an environmental endocrine disruptor, in the serum and skin of captive FMDs. Feeding FMDs with maslinic acid (MA) has been observed to alleviate the stress response and improve reproductive rates, although the precise molecular mechanisms remain unclear. Therefore, this study aims to investigate the molecular mechanisms underlying the alleviation of DEHP-induced oxidative stress and cell apoptosis in primary peritubular myoid cells (PMCs) through MA intake. Primary PMCs were isolated and exposed to DEHP in vitro. The results demonstrated that DEHP significantly suppressed antioxidant levels and promoted cell apoptosis in primary PMCs. Moreover, interfering with the expression of PRDX6 was found to induce excessive reactive oxygen species (ROS) production and cell apoptosis in primary PMCs. Supplementation with MA significantly upregulated the expression of PRDX6, thereby attenuating DEHP-induced oxidative stress and cell apoptosis in primary PMCs. These findings provide a theoretical foundation for mitigating stress levels and enhancing reproductive capacity of in captive FMDs.

miR-128-3p is involved in aluminum-induced cognitive impairment by regulating the Sirt1-Keap1/Nrf2 pathway

Aluminum (Al) is a common neurotoxicant in the environment, but the molecular mechanism of its toxic effects is still unclear. Studies have shown that aluminum exposure causes an increase in neuronal apoptosis. The aim of this study was to investigate the mechanism and signaling pathway of neuronal apoptosis induced by aluminum exposure. The rat model was established by intraperitoneal injection of maltol aluminum for 90 days. The results showed that the escape latency of the three groups exposed to maltol aluminum was higher than that of the control group on the 3rd, 4th and 5th days of the positioning cruise experiment (P < 0.05). On the 6th day of the space exploration experiment, compared with the control group(6.00 ± 0.71,15.33 ± 1.08) and the low-dose group(5.08 ± 1.69,13.67 ± 1.09), the number of times that the high-dose group crossed the platform(2.25 ± 0.76) and the platform quadrant(7.58 ± 1.43) was significantly reduced (P < 0.01). The relative expression levels of Sirt1 and Nrf2 in hippocampal tissues of all groups decreased gradually with increasing maltol aluminum exposure dose the relative expression levels of Sirt1 and Nrf2 in high-dose group (0.261 ± 0.094,0.325 ± 0.108) were significantly lower than those in control group (1.018 ± 0.222,1.009 ± 0.156)(P < 0.05). The relative expression level of Keap1 increased gradually with increasing maltol aluminum exposure dose (P < 0.05). The relative expression level of miR-128-3p in the high-dose group(1.520 ± 0.280) was significantly higher than that in the control group(1.000 ± 0.420) (P < 0.05). The content of GSH-Px in the hippocampus of rats decreased with increasing dose. ROS levels gradually increased. We speculated that subchronic aluminum exposure may lead to the activation of miR-128-3p in rat hippocampus of rats, thereby inhibiting the Sirt1-Keap1/Nrf2 pathway so that the Sirt1-Keap1/Nrf2 pathway could not be activated to exert antioxidant capacity, resulting in an imbalance in the antioxidant system of rats and the apoptosis of neurons, which caused reduced cognitive impairment in rats.

Role of intrinsic apoptosis in environmental exposure health outcomes

Environmental exposures are linked to diseases of high public health concern, including cancer, neurodegenerative disorders, and autoimmunity. These diseases are caused by excessive or insufficient cell death, prompting investigation of mechanistic links between environmental toxicants and dysregulation of cell death pathways, including apoptosis. This review describes how legacy and emerging environmental exposures target the intrinsic apoptosis pathway to potentially drive pathogenesis. Recent discoveries reveal that dynamic regulation of apoptosis may heighten the vulnerability of healthy tissues to exposures in children, and that apoptotic signaling can guide immune responses, tissue repair, and tumorigenesis. Understanding how environmental toxicants dysregulate apoptosis will uncover opportunities to deploy apoptosis-modulating agents for the treatment or prevention of exposure-linked diseases.

Endoplasmic reticulum stress and pro-inflammatory responses induced by phthalate metabolites monoethylhexyl phthalate and monobutyl phthalate in 1.1B4 pancreatic beta cells

In recent years, phthalates and their metabolites have been associated with metabolic diseases such as diabetes mellitus. To investigate the effects of phthalate metabolites exposure on insulin production and release, 1.1B4 pancreatic beta cells were treated with different concentrations (0.001-1000 µM) of monoethylhexyl phthalate (MEHP) and monobutyl phthalate (MBP). For such purpose, the 1.1B4 cells were evaluated for their viability, apoptosis rate, lysosomal membrane permeabilization (LMP), mitochondrial membrane potential (ΔΨm), oxidative stress, ER stress status, in addition to their secretory functions. MEHP, not MBP, exhibited a notable reduction in metabolic viability, particularly at higher concentrations (500 and 1000 µM) following 24-hour exposure. Similarly, both MEHP and MBP induced decreased metabolic viability at high concentrations after 48- and 72-hour exposure. Notably, neither MEHP nor MBP demonstrated a significant impact on apoptosis rates after 24-hour exposure, and MBP induced mild necrosis at 1000 µM concentration. Cell proliferation rates, indicated by PCNA expression, decreased with 10 and 1000 µM MEHP and 0.1 and 10 µM MBP exposures. LMP analysis revealed an increase in 1000 µM MBP group. Exposure to 0.001 µM of both MEHP and MBP significantly reduced cellular glutathione (GSH) levels. No significant change in intracellular reactive oxygen species (ROS) levels and ΔΨm was observed, but MBP-exposed cells exhibited elevated levels of lipid peroxidation. Functional assessments of pancreatic beta cells unveiled reduced insulin secretion at low glucose concentrations following exposure to both MEHP and MBP, with concurrent alterations in the expression levels of key proteins associated with beta cell function, including GLUT1, GCK, PDX1, and MafA. Moreover, MEHP and MBP exposures were associated with alterations in ER stress-related pathways, including JNK, GADD153, and NF-κB expression, as well as PPARα and PPARγ levels. In conclusion, this study provides comprehensive insights into the diverse impacts of MEHP and MBP on 1.1B4 pancreatic beta cells, emphasizing their potential role in modulating cell survival, metabolic function, and stress response pathways.

DDIT4 is essential for DINP-induced autophagy of ovarian granulosa cells

As one of the most important phthalates, di-isononyl phthalate (DINP) has been widely used as a common plasticizer in the food and personal care products sectors. In our previous study, we found that DINP can induce autophagy of ovarian granulosa cells; while the underlying mechanism is unclear. In the study, we showed that DINP exposure could induce autophagy of ovarian granulosa cells and KGN cells, accompanied with the increase in the mRNA and protein level of DDIT4. Furthermore, overexpression of DDIT4 were shown to induce autophagy of KGN cells; while knockdown of DDIT4 inhibited DINP-induced autophagy, implying that DDIT4 played an important role in DINP-induced autophagy of ovarian granulosa cells. There were three putative binding sites of transcription factor ATF4 in the promoter region of DDIT4 gene, suggesting that DDIT4 might be regulated by ATF4. Herein, we found that overexpression of ATF4 could upregulate the expression of DDIT4 in KGN cells, while knockdown of ATF4 inhibited its expression. Subsequently, ATF4 was identified to bind to the promoter region of DDIT4 gene and promote its transcription. The expression of ATF4 was also increased in the DINP-exposed granulosa cells, and ATF4 overexpression promoted autophagy of KGN cells; whereas knockdown of ATF4 alleviated DINP-induced upregulation of DDIT4 and autophagy of the cells. Taken together, DINP triggered autophagy of ovarian granulosa cells through activating ATF4/DDIT4 signals.

Combined Astragalus, vitamin C, and vitamin E alleviate DEHP-induced oxidative stress and the decreased of insulin synthesis and secretion in INS-1 cells

Di-(2-ethylhexyl)-phthalate (DEHP), a common Phthalic acid ester (PAEs), has been reported to be associated with diabetes mellitus, yet the underlying mechanisms remain unknown. Combined nutrient interventions have been shown to alleviate the diabetic toxicity of DEHP. However, the effects and mechanisms of the combined intervention of Astragalus and vitamins (C and E) are currently unknown. In this study, we investigated the potential mechanisms of DEHP-induced diabetes mellitus through transcriptome analysis and vitro experiments using rat insulinoma cells (INS-1 cells). Furthermore, we explored the protection of the combined Astragalus, vitamin C, and vitamin E on DEHP-induced diabetes mellitus through these mechanisms. INS-1 cells in the logarithmic growth period were exposed to 125 umol/L DEHP followed by high-throughput sequencing analysis. The cell proliferation inhibition rate was determined using MTT assay for each group, and the cell apoptosis rate and intracellular ROS level were measured using flow cytometer. Finally, insulin levels and markers of oxidative stress were detected using ELISA kits in different groups. A total of 372 differentially expressed genes were found between the 125 umol/L DEHP and control groups, subsequent functional enrichment analyses indicated that DEHP induced oxidative stress and disturbed insulin levels. In INS-1 cells, the rate of cell proliferation inhibition, apoptosis, and the degree of oxidative stress increased concentration-dependently with increasing DEHP concentrations, while antioxidant intervention could reverse these changes. Insulin synthesis and secretion decreased after 240 μmol/L DEHP exposure stimulated by 25 mM glucose in INS-1 cells, also could antioxidant intervention alleviate these reductions. Based on these results, the underlying mechanism of DEHP impairing the function of INS-1 cells might be through apoptosis pathways induced by oxidative stress and direct reduction of insulin levels (both synthesis and secretion), while the optimal combination of Astragalus and vitamins (C and E) could exert an alleviating effect.

Adverse cardiovascular effects of long-term exposure to diethyl phthalate in the rat aorta

Phthalates are classified as priority environmental pollutants, since they are ubiquitous in the environment, have endocrine disrupting properties and can contribute to impaired health. Used primarily in personal care products and excipients for pharmaceuticals, diethyl phthalate (DEP) is a short-chain alkyl phthalate that has been linked to decreased blood pressure, glucose tolerance, and increased gestational weight gain in humans, while in animals it has been associated with atherosclerosis and metabolic syndrome. Although all these findings are related to risk factors or cardiovascular diseases, DEP's vascular impacts still need to be clarified. Thus, performing ex vivo and in vitro experiments, we aimed to understand the vascular DEP effects in rat. To evaluate the vascular contractility of rat aorta exposed to different doses of DEP (0.001-1000 μM), an organs bath was used; and resorting to a cell line of the rat aorta vascular smooth muscle, electrophysiology experiments were performed to analyse the effects of a rapid (within minutes with no genomic effects) and a long-term (24 h with genomic effects) exposure of DEP on the L-type Ca2+ current (ICa,L), and the expression of several genes related with the vascular function. For the first time, vascular electrophysiological properties of an EDC were analysed after a long-term genomic exposure. The results show a hormetic response of DEP, inducing a Ca2+ current inhibition of the rat aorta, which may be responsible for impaired cardiovascular electrical health. Thus, these findings contribute to a greater scientific knowledge about DEP's effects in the cardiovascular system, specifically its implications in the development of electrical disturbances like arrhythmias and its possible mechanisms.

The Hidden Threat: Endocrine Disruptors and Their Impact on Insulin Resistance

The association between Insulin resistance, a global health issue, and endocrine disruptors (EDCs), chemicals interfering with the endocrine system, has sparked concern in the scientific community. This article provides a comprehensive review of the existing literature regarding the intricate relationship between EDCs and insulin resistance. Phthalates, commonly found in consumer products, are well-established EDCs with documented effects on insulin-signaling pathways and metabolic processes. Epidemiological studies have connected phthalate exposure to an increased risk of type 2 diabetes mellitus (T2DM). Perfluoroalkyl substances (PFAS), persistent synthetic compounds, have shown inconsistent associations with T2DM in epidemiological research. However, studies suggest that PFAS may influence insulin resistance and overall metabolic health, with varying effects depending on specific PFAS molecules and study populations. Bisphenol A (BPA), found in plastics and resins, has emerged as a concern for glucose regulation and insulin resistance. Research has linked BPA exposure to T2DM, altered insulin release, obesity, and changes in the mass and function of insulin-secreting β-cells. Triclosan, an antibacterial agent in personal care products, exhibits gender-specific associations with T2DM risk. It may impact gut microbiota, thyroid hormones, obesity, and inflammation, raising concerns about its effects on metabolic health. Furthermore, environmental EDCs like polycyclic aromatic hydrocarbons, pesticides, and heavy metals have demonstrated associations with T2DM, insulin resistance, hypertension, and obesity. Occupational exposure to specific pesticides and heavy metals has been linked to metabolic abnormalities.

Green tea polyphenols alleviate di-(2-ethylhexyl) phthalate-induced liver injury in mice

BACKGROUND

Di (2-ethylhexyl) phthalate (DEHP) is a common plasticizer known to cause liver injury. Green tea is reported to exert therapeutic effects on heavy metal exposure-induced organ damage. However, limited studies have examined the therapeutic effects of green tea polyphenols (GTPs) on DEHP-induced liver damage.

AIM

To evaluate the molecular mechanism underlying the therapeutic effects of GTPs on DEHP-induced liver damage.

METHODS

C57BL/6J mice were divided into the following five groups: Control, model [DEHP (1500 mg/kg bodyweight)], treatment [DEHP (1500 mg/kg bodyweight) + GTP (70 mg/kg bodyweight), oil, and GTP (70 mg/kg bodyweight)] groups. After 8 wk, the liver function, blood lipid profile, and liver histopathology were examined. Differentially expressed micro RNAs (miRNAs) and mRNAs in the liver tissues were examined using high-throughput sequencing. Additionally, functional enrichment analysis and immune infiltration prediction were performed. The miRNA-mRNA regulatory axis was elucidated using the starBase database. Protein expression was evaluated using immunohistochemistry.

RESULTS

GTPs alleviated DHEP-induced liver dysfunction, blood lipid dysregulation, fatty liver disease, liver fibrosis, and mitochondrial and endoplasmic reticulum lesions in mice. The infiltration of macrophages, mast cells, and natural killer cells varied between the model and treatment groups. mmu-miR-141-3p (a differentially expressed miRNA), Zcchc24 (a differentially expressed mRNA), and Zcchc24 (a differentially expressed protein) constituted the miRNA-mRNA-protein regulatory axis involved in mediating the therapeutic effects of GTPs on DEHP-induced liver damage in mice.

CONCLUSION

This study demonstrated that GTPs mitigate DEHP-induced liver dysfunction, blood lipid dysregulation, fatty liver disease, and partial liver fibrosis, and regulate immune cell infiltration. Additionally, an important miRNA-mRNA-protein molecular regulatory axis involved in mediating the therapeutic effects of GTPs on DEHP-induced liver damage was elucidated.

Endocrine disruptors in plastics alter β-cell physiology and increase the risk of diabetes mellitus

Plastic pollution breaks a planetary boundary threatening wildlife and humans through its physical and chemical effects. Of the latter, the release of endocrine disrupting chemicals (EDCs) has consequences on the prevalence of human diseases related to the endocrine system. Bisphenols (BPs) and phthalates are two groups of EDCs commonly found in plastics that migrate into the environment and make low-dose human exposure ubiquitous. Here we review epidemiological, animal, and cellular studies linking exposure to BPs and phthalates to altered glucose regulation, with emphasis on the role of pancreatic β-cells. Epidemiological studies indicate that exposure to BPs and phthalates is associated with diabetes mellitus. Studies in animal models indicate that treatment with doses within the range of human exposure decreases insulin sensitivity and glucose tolerance, induces dyslipidemia, and modifies functional β-cell mass and serum levels of insulin, leptin, and adiponectin. These studies reveal that disruption of β-cell physiology by EDCs plays a key role in impairing glucose homeostasis by altering the mechanisms used by β-cells to adapt to metabolic stress such as chronic nutrient excess. Studies at the cellular level demonstrate that BPs and phthalates modify the same biochemical pathways involved in adaptation to chronic excess fuel. These include changes in insulin biosynthesis and secretion, electrical activity, expression of key genes, and mitochondrial function. The data summarized here indicate that BPs and phthalates are important risk factors for diabetes mellitus and support a global effort to decrease plastic pollution and human exposure to EDCs.

Bisphenol F induced hyperglycemia via activation of oxidative stress-responsive miR-200 family in the pancreas

Bisphenol F (BPF), BPS and BPAF are gaining popularity as main substitutes to BPA, but there is no clear evidence that these compounds disrupt glycemic homeostasis in the same way. In this study, four bisphenols were administered to C57BL/6 J mice, and showed that the serum insulin was elevated in the BPA and BPS exposed mice, whereas BPF exposed mice exhibited lower serum insulin and higher blood glucose. BPF decreased oxidized glutathione/reduced glutathione ratio (GSSG/GSH) and N6-methyladenosine (m6A) levels, which was responsible for pancreatic apoptosis in mice. Additionally, the downregulation of Nrf2 and the aberrant regulation of the p53-lncRNA H19 signaling pathway further increased miR-200 family in the BPF-exposed pancreas. The miR-200 family directly suppressed Mettl14 and Xiap by targeting their 3' UTR, leading to islet apoptosis. Antioxidant treatment not only elevated m6A levels and insulin contents but also suppressed the miR-200 family in the pancreas, ultimately improving BPF-induced hyperglycemia. Taken together, miR-200 family could serve as a potential oxidative stress-responsive regulator in the pancreas. And moreover, we demonstrated a novel toxicological mechanism in that BPF disrupted the Keap1-Nrf2 redox system to upregulate miR-141/200b/c which controlled pancreatic insulin production and apoptosis via Mettl14 and Xiap, respectively. As the major surrogates of BPA in various applications, BPF was also diabetogenic, which warrants attention in future research.

Metabolomic analysis of the inhibitory effect of phthalates and bisphenol A on the antioxidant activity of vitamin D in human samples using liquid chromatography–mass spectrometry

Vitamin D is important because it has roles in maintaining musculoskeletal health, redox homeostasis, and the immune system; however, it is commonly dysregulated by endocrine disrupting chemicals, particularly phthalates and bisphenol A (BPA). Continuous exposure to phthalates and BPA may alter the endogenous metabolite profiles associated with vitamin D activity, although the specific metabolites are yet to be identified. In this study, we identified the endogenous metabolites altered by phthalates and BPA exposure through untargeted metabolic profiling and investigated the role of these metabolites in vitamin D activity. Plasma metabolic profiling using liquid chromatography-mass spectrometry was performed in two groups: severe 25-hydroxyvitamin D (25(OH)D) deficiency and high exposure to phthalates and BPA (Group A) and 25(OH)D deficiency and low exposure to phthalates and BPA (Group B). Multivariate analysis revealed a distinct separation between the two groups. A total of six metabolites were annotated, of which levels of two were significantly different between the two groups: platelet-activating factor (PAF) C16 or lysophosphatidylcholine (lysoPC) 18:0, and 11Z-eicosenamide. Plasma levels of PAF C16 or lysoPC 18:0 were increased in Group A and exhibited an area under the curve of 0.769 with an accuracy of 74.4% in a receiver operating characteristic curve analysis. These metabolites are generated as byproducts of lipid peroxidation, which supports the fact that phthalates and BPA induce oxidative stress in cells. Furthermore, PAF C16 and lysoPC 18:0 may be involved in the network that interferes with the antioxidant activity of vitamin D upon exposure to phthalates and BPA. This study results provide useful information on how the activity of vitamin D on the antioxidant system is inhibited when exposure to phthalates and BPA.

Effects of single or combined exposure to bisphenol A and mono(2-ethylhexyl)phthalate on oxidant/antioxidant status, endoplasmic reticulum stress, and apoptosis in HepG2 cell line

Endocrine disrupting chemicals (EDCs) may affect many biological processes like growth and stress response. Bisphenol A (BPA) is a plasticizer that is used to harden plastics and polycarbonates. Phthalates are used to add flexibility to polyvinyl chloride containing plastics. The main metabolite of di(2-ethylhexyl) phthalate (DEHP) is mono(2-ethylhexyl) phthalate (MEHP) and it is even more toxic than the parent compound. Humans are usually exposed to these chemicals in mixtures by different routes starting from fetal period. However, there are not many studies in literature that investigate the combined effects of these chemicals. The aim of this study is to investigate toxic effects of BPA and/or MEHP on HepG2 cell line. We have evaluated cytotoxicity, cytomorphological, apoptotic changes, oxidative stress, oxidant/antioxidant status alterations, and endoplasmic reticulum (ER) stress. Combined exposure to BPA and MEHP caused alterations in oxidant/antioxidant status and ER stress marker proteins in both cytoplasmic and nuclear cellular fractions. We can suggest that combined exposure to EDCs may cause serious toxicological outcomes and more mechanistic studies are needed to determine the combined toxic effects.

Combinatorial pathway disruption is a powerful approach to delineate metabolic impacts of endocrine disruptors

The prevalence of metabolic diseases, such as obesity, diabetes, metabolic syndrome and chronic liver diseases among others, has been rising for several years. Epidemiology and mechanistic (in vivo, in vitro and in silico) toxicology have recently provided compelling evidence implicating the chemical environment in the pathogenesis of these diseases. In this review, we will describe the biological processes that contribute to the development of metabolic diseases targeted by metabolic disruptors, and will propose an integrated pathophysiological vision of their effects on several organs. With regard to these pathomechanisms, we will discuss the needs, and the stakes of evolving the testing and assessment of endocrine disruptors to improve the prevention and management of metabolic diseases that have become a global epidemic since the end of last century.

DEHP triggers a damage severity grade increase in the jejunum in quail (Coturnix japonica) by disturbing nuclear xenobiotic receptors and the Nrf2-mediated defense response

As a plasticizer, di-2-ethylhexyl phthalate (DEHP) has been listed as a potential endocrine disruptor by The World Health Organization. The toxicity of DEHP has been widely studied, but its toxicity on the digestive tract of birds has not been clarified. Female quail were treated by gavage with DEHP (250, 500, 750 mg/kg), with the blank and vehicle control groups reserved. The result showed that DEHP raised the damage severity grade, and decreased the ratio of villus length to crypt depth. The content and activity of cytochrome P450 system (CYP450s) were increased by DEHP. DEHP interfered with the transcription of nuclear xenobiotic receptors (NXRs), CYP isoforms, and the nuclear factor-E2-related factor 2 (Nrf2) signaling pathway. This study revealed DEHP could cause the imbalance in CYP450s mediated by NXRs, and then promote Nrf2 mediated antioxidant defense. This study provided new evidence about the mechanisms of DEHP-induced toxic effects on digestive tract.

Cytotoxicity evaluation and mechanism of endocrine-disrupting chemicals by the embryoid body test

Endocrine-disrupting chemicals (EDCs) are a structurally diverse class of synthetic and natural compounds. EDCs can cause non-communicable diseases such as obesity, type 2 diabetes, thyroid disorders, neurodevelopmental disease, hormone-dependent cancers, and reproductive disorders. The embryoid body test (EBT) is a developmental toxicity test method that determines the size of embryoid bodies (EBs) and the viability of mouse embryonic stem cells (mESCs) and fibroblasts (3T3 cells). The present study used the EBT to perform cytotoxicity evaluations of 10 EDCs and assessed the mechanistic relationship between endoplasmic reticulum (ER) stress and cytotoxicity. According to the statistical analysis and prediction model results, methylparaben, butylparaben, propylparaben, ethylparaben, triclosan, octylphenol, methoxychlor, bisphenol A, and diethylstilbestrol were classified as cytotoxic, but trichloroacetic acid was non-toxic. Classification accuracy was 90%. The mechanistic study showed that the cytotoxicities of butylparaben, propylparaben, octylphenol, and triclosan were induced by ER stress. The mRNA expressions of BiP, CHOP, and ATF4 were significantly higher following treatments with four EDCs compared to those after the control treatment. Compared to the control treatment, the mRNA levels of XBP1u and XBP1s increased significantly after butylparaben and propylparaben treatments, but did not increase with octylphenol and triclosan treatments. These results indicate that the EBT can be applied as an alternative toxicity test when evaluating the cytotoxicity of EDCs.

Chronic exposure to environmentally relevant levels of di(2-ethylhexyl) phthalate (DEHP) disrupts lipid metabolism associated with SBP-1/SREBP and ER stress in C. elegans

DEHP is commonly found in the environment, biota, food, and humans, raising significant health concerns. Whether developmental stage and exposure duration modify the obesogenic effects of DEHP is unclear, especially the underlying mechanisms by which chronic exposure to DEHP as well as its metabolites remain largely unknown. This study investigated the obesogenic effects of chronic DEHP exposure, with levels below environmentally-relevant amounts and provide the mechanism in Caenorhabditis elegans. We show that early-life DEHP exposure resulted in an increased lipid and triglyceride (TG) accumulation mainly attributed to DEHP itself, not its metabolite mono-2-ethylhexyl phthalate (MEHP). In addition, developmental stage and exposure timing influence DEHP-induced TG accumulation and chronic DEHP exposure resulted in the most significant effect. Analysis of fatty acid composition shows that chronic DEHP exposure altered fatty acid composition and TG, resulting in an increased ω-6/ω-3 ratio. The increased TG content by chronic DEHP exposure required lipogenic genes fat-6, fat-7, pod-2, fasn-1, and sbp-1. Moreover, chronic DEHP exposure induced XBP-1-mediated endoplasmic reticulum (ER) stress which might lead to up-regulation of sbp-1. This study suggests the possible involvement of ER stress and SBP-1/SREBP-mediated lipogenesis in chronic DEHP-induced obesogenic effects. Results from this study implies that chronic exposure to DEHP disrupts lipid metabolism, which is likely conserved across species due to evolutionary conservation of molecular mechanisms, raising concerns in ecological and human health.

Exposure to perfluorooctane sulfonate reduced cell viability and insulin release capacity of β cells

Per- and polyfluoroalkyl substances (PFAS) are found to have multiple adverse outcomes on human health. Recently, epidemiological and toxicological studies showed that exposure to PFAS had adverse impacts on pancreas and showed association with insulin abnormalities. To explore how PFAS may contribute to diabetes, we studied impacts of perfluorooctane sulfonate (PFOS) on cell viability and insulin release capacity of pancreatic β cells by using in vivo and in vitro methods. We found that 28-day administration with PFOS (10 mg/(kg body weight•day)) caused reductions of pancreas weight and islet size in male mice. PFOS administration also led to lower serum insulin level both in fasting state and after glucose infusion among male mice. For cell-based in vitro bioassay, we used mouse β-TC-6 cancer cells and found 48-hr exposure to PFOS decreased the cell viability at 50 μmol/L. By measuring insulin content in supernatant, 48-hr pretreatment of PFOS (100 μmol/L) decreased the insulin release capacity of β-TC-6 cells after glucose stimulation. Although these concentrations were higher than the environmental concentration of PFOS, it might be reasonable for high concentration of PFOS to exert observable toxic effects in mice considering mice had a faster removal efficiency of PFOS than human. PFOS exposure (50 μmol/L) to β-TC-6 cells induced intracellular accumulation of reactive oxidative specie (ROS). Excessive ROS induced the reactive toxicity of cells, which eventually invoke apoptosis and necrosis. Results in this study provide evidence for the possible causal link of exposure to PFOS and diabetes risk.

Screening of Relevant Metabolism-Disrupting Chemicals on Pancreatic β-Cells: Evaluation of Murine and Human In Vitro Models

Endocrine-disrupting chemicals (EDCs) are chemical substances that can interfere with the normal function of the endocrine system. EDCs are ubiquitous and can be found in a variety of consumer products such as food packaging materials, personal care and household products, plastic additives, and flame retardants. Over the last decade, the impact of EDCs on human health has been widely acknowledged as they have been associated with different endocrine diseases. Among them, a subset called metabolism-disrupting chemicals (MDCs) is able to promote metabolic changes that can lead to the development of metabolic disorders such as diabetes, obesity, hepatic steatosis, and metabolic syndrome, among others. Despite this, today, there are still no definitive and standardized in vitro tools to support the metabolic risk assessment of existing and emerging MDCs for regulatory purposes. Here, we evaluated the following two different pancreatic cell-based in vitro systems: the murine pancreatic β-cell line MIN6 as well as the human pancreatic β-cell line EndoC-βH1. Both were challenged with the following range of relevant concentrations of seven well-known EDCs: (bisphenol-A (BPA), bisphenol-S (BPS), bisphenol-F (BPF), perfluorooctanesulfonic acid (PFOS), di(2-ethylhexyl) phthalate (DEHP), cadmium chloride (CdCl2), and dichlorodiphenyldichloroethylene (DDE)). The screening revealed that most of the tested chemicals have detectable, deleterious effects on glucose-stimulated insulin release, insulin content, electrical activity, gene expression, and/or viability. Our data provide new molecular information on the direct effects of the selected chemicals on key aspects of pancreatic β-cell function, such as the stimulus-secretion coupling and ion channel activity. In addition, we found that, in general, the sensitivity and responses were comparable to those from other in vivo studies reported in the literature. Overall, our results suggest that both systems can serve as effective tools for the rapid screening of potential MDC effects on pancreatic β-cell physiology as well as for deciphering and better understanding the molecular mechanisms that underlie their action.

Quercetin ameliorates Di (2-ethylhexyl) phthalate-induced nephrotoxicity by inhibiting NF-κB signaling pathway

This study aimed to evaluate the possible protective effects of quercetin, a natural flavonoid, against nephrotoxicity induced by Di (2-ethylhexyl) phthalate (DEHP) in kidney tissue of rats and human embryonic kidney (HEK) 293 cell line. The HEK-293 cells were treated with different concentrations of quercetin 24 h before treatment with monoethylhexyl phthalate (MEHP). Male rats were treated with 200-mg/kg DEHP, 200-mg/kg DEHP plus quercetin (50 and 100 mg/kg), and 200-mg/kg DEHP plus vitamin E (20 mg/kg) for 45 days by gavage. Quercetin treatment reduced cytotoxicity and oxidative damage inducing by MEHP in HEK-293 cells. The in vivo findings showed that 100-mg/kg quercetin significantly suppressed DEHP-induced kidney damage. For exploring the involved mechanisms, the expressions of nuclear factor E2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), nuclear factor kappa B (NFκB), and tumor necrosis factor alpha (TNFα) genes were determined via real-time Polymerase chain reaction (PCR) assay. High dose of quercetin significantly decreased the gene expressions of NF-κB and TNFα, whereas the alternations of Nrf2 and HO-1 gene expressions were not significant in quercetin groups in compared with DEHP group. These findings suggested that the suppression of DEHP-induced nephrotoxicity via quercetin is correlated, at least in part, with its potential to regulate NF-κB signaling pathway.

Endocrine-Disrupting Chemicals and Their Adverse Effects on the Endoplasmic Reticulum

There is growing concern regarding the health and safety issues of endocrine-disrupting chemicals (EDCs). Long-term exposure to EDCs has serious adverse health effects through both hormone-direct and hormone-indirect ways. Accordingly, some EDCs can be a pathogen and an inducer to the susceptibility of disease, even if they have a very low affinity on the estrogen receptor, or no estrogenic effect. Endoplasmic reticulum (ER) stress recently attracted attention in this research area. Because ER and ER stress could be key regulators of the EDC’s adverse effects, such as the malfunction of the organ, as well as the death, apoptosis, and proliferation of a cell. In this review, we focused on finding evidence which shows that EDCs could be a trigger for ER stress and provide specific examples of EDCs, which are known to cause ER stress currently.

Lycopene prevents DEHP-induced testicular endoplasmic reticulum stress via regulating nuclear xenobiotic receptors and unfolded protein response in mice

Lycopene (LYC) is a potent antioxidant synthesized by red vegetables or plants. Di-2-ethylhexyl phthalate (DEHP) is frequently detected in diverse agricultural environments and considered as a reproductive toxicant. The present research was designed to assess the potential mechanisms of DEHP-induced testicular toxicity and the treatment efficacy of LYC. In this study, after the oral administration of LYC at the dose of 5 mg per kg b.w. per day, mice were given 500 or 1000 mg per kg b.w. per day of DEHP. This research suggested that LYC prevented the DEHP-induced disorder at the levels of activity and content of CYP450 enzymes. LYC attenuated DEHP-caused enhancement in nuclear xenobiotic receptors (NXRs) and the phase I metabolizing enzymes (CYP1, CYP2, CYP3, etc.) levels. Furthermore, endoplasmic reticulum (ER) stress was induced by DEHP and triggered unfolded protein response (UPR). Interestingly, LYC could effectively ameliorate these "hit". The present study suggested that LYC prevents DEHP-induced ER stress in testis via regulating NXRs and UPRER.

DMEP induces mitochondrial damage regulated by inhibiting Nrf2 and SIRT1/PGC-1α signaling pathways in HepG2 cells

Dimethoxyethyl phthalate (DMEP) is an environmental endocrine disruptor. However, research into the underlying mechanisms of DMEP mitochondrial toxicity is still in its infancy. We therefore expect to understand whether DMEP induced mitochondrial damage in HepG2 cells and the associated signaling pathways. DMEP (0.125, 0.25, 0.5, 1 and 2 mM) exposure for 48 h induced a notable increment in reactive oxygen species (ROS), malondialdehyde (MDA), alanine aminotransferase (ALT), aspartate transaminase (AST) and 8-hydroxydeoxyguanosine (8-OHdG) in hepG2 cells, resulting in cellular oxidative stress. Low doses of DMEP upregulated nuclear factor E2-related factor 2 (Nrf2) and downstream protein haeme oxygenase-1 (HO-1) levels and high doses down-regulated their levels. Nrf2 levels increased after ROS scavenging by N-acetyl-L-cysteine (NAC), which indicated that the Nrf2 pathway may be affected by oxidative stress. We also found that DMEP decreased ATP content, mitochondrial copy number (mtDNA), translocase of the outer membrane subunit 20 (TOM20) expression, mitochondria-encoded genes CO1, CO2, CO3, ATP6, ATP8 expression, inhibited mitochondrial biogenesis pathway, down-regulated sirtuin 1(SIRT1), PPAR gamma co-activator 1 alpha (PGC-1α), Nuclear respiratory factor 1(Nrf1), Mitochondrial transcription factor A (TFAM) content and activated PINK1/Parkin autophagy pathway. DMEP also activated the mitochondrial apoptotic pathway, causing cytochrome c cytoplasmic translocation and caspase 3 cleavage. What's more, DMEP activated the Nuclear factor-κB (NF-κB) pathway and levels of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6) were significantly upregulated, causing an inflammatory response. In summary, DMEP can cause inflammatory response and oxidative stress in HepG2 cells, inhibited the Nrf2 pathway and mitochondrial biogenesis, and induced autophagy and apoptosis. And oxidative stress at least partially affected the Nrf2 pathway and mitochondrial biogenesis SIRT1/PGC-1α pathway.

Mechanistic insight into toxicity of phthalates, the involved receptors, and the role of Nrf2, NF-κB, and PI3K/AKT signaling pathways

The wide use of phthalates, as phthalates are used in the manufacturing of not only plastics but also many others goods, has become a main concern in the current century because of their potency to induce deleterious effects on organism health. The toxic effects of phthalates such as reproductive toxicity, cardiotoxicity, hepatotoxicity, nephrotoxicity, teratogenicity, and tumor development have been widely indicated by previous experimental studies. Some of the important mechanisms of toxicity by phthalates are the induction and promotion of inflammation, oxidative stress, and apoptosis. Awareness of the involved molecular pathways of these mechanisms will permit the detection of exact molecular targets of phthalates to protect or treat their toxicity. Up to now, various transcription factors and signaling pathways have been associated with phthalate-induced toxicity which by influencing on nuclear surface and the expression of different genes can alter cell hemostasis. In different studies, the role of nuclear factor erythroid 2-related factor 2 (Nrf2), nuclear factor-κB (NF-κB), and phosphatidylinositol-3-kinase (PI3K)/AKT signaling pathways in processes of oxidative stress, inflammation, apoptosis, and cancer has been shown following exposure to phthalates. In the present review, we aim to survey experimental studies (in vitro and in vivo) in order to show firstly the most involved receptors and also the importance and the role of the mentioned signaling pathways in phthalate-induced toxicity, and with considering this point, the future studies can focus on these molecular targets as a strategic method to reduce environmental chemicals-induced toxicity especially phthalates toxic effects.

Effects of Phthalate Esters (PAEs) on Cell Viability and Nrf2 of HepG2 and 3D-QSAR Studies

Phthalate esters (PAEs) are a widespread environmental pollutant, and their ecological and environmental health risks have gradually attracted attention. To reveal the toxicity characteristics of these compounds, ten PAEs were selected as research objects to establish a cell model. CCK-8 was used to determine cell viability, Western blots were used to determine the content of Nrf₂ in HepG2, and the LD₅₀ collected for the 13 PAEs administered to rats. On this basis, 3D-QSAR models of IC₅₀, LD₅₀ and Nrf2 were established. The experimental results showed that as the time of PAEs exposure increased (24, 48 and 72 h), cell viability gradually decreased. The test concentration (62.5 /125/250 μM) of PAEs exposed for 48 h could significantly increase the content of Nrf2, and the 1000 μM PAEs could inhibit the content of Nrf2. The model is relatively stable and predicts well that the introduction of large and hydrophobic groups may significantly affect the toxic effects of PAEs on cells. The present study provided a potential tool for predicting the LD50 and Nrf2 of new PAEs, and provide a reference for the design of new less toxic PAEs in the future.

Probiotic reduced the impact of phthalates and bisphenol A mixture on type 2 diabetes mellitus development: Merging bioinformatics with in vivo analysis

Linkage between bis(2-ethylhexyl) phthalate (DEHP), dibutyl phthalate (DBP), and bisphenol A (BPA) co-exposure and type 2 diabetes mellitus (T2DM), as well as ability of multi-strained probiotic to reduce DEHP, DBP and BPA mixture-induced oxidative damage in rat pancreas were investigated. The Comparative Toxicogenomics Database, Cytoscape software and ToppGene Suite were used for data-mining. Animals were sorted into seven groups (n = 6): (1) Control group: corn oil, (2) P: probiotic: Saccharomyces boulardii + Lactobacillus rhamnosus + Lactobacillus plantarum LP 6595 + Lactobacillus plantarum HEAL9; (3) DEHP: 50 mg/kg b.w./day, (4) DBP: 50 mg/kg b.w./day, (5) BPA: 25 mg/kg b.w./day, and (6) MIX: 50 mg/kg b.w./day DEHP + 50 mg/kg b.w/day DBP + 25 mg/kg b.w./day BPA; (7) MIX + P. Rats were sacrificed after 28 days of oral exposure. In silico investigation highlighted 44 DEHP, DBP and BPA mutual genes linked to the T2DM, while apoptosis and oxidative stress were highlighted as the main mechanisms of DEHP, DBP and BPA mixture-linked T2DM. In vivo experiment confirmed the presence of significant changes in redox status parameters (TOS, SOD and SH groups) only in the MIX group, indicating possible additive effects, while probiotic ameliorated mixture-induced redox status changes in rat pancreatic tissue.

Di-(2-ethylhexyl) phthalate induces testicular endoplasmic reticulum stress and germ cell apoptosis in adolescent mice

Di-(2-ethylhexyl) phthalate (DEHP) is a male reproductive toxicant. This research is aimed at investigating the effect of pubertal DEHP exposure on testicular endoplasmic reticulum (ER) stress and germ cell apoptosis. Five-week-old male mice were orally administered with DEHP (0, 0.5, 50, or 500 mg/kg/day) for 35 days. Testis weight and sperm count were reduced in mice exposed to 500 mg/kg/day DEHP. The number of seminiferous tubules in stages VII-VIII, mature seminiferous tubules, was reduced and the number of seminiferous tubules in stages IX-XII, immature seminiferous tubules, was elevated in mice treated with 500 mg/kg/day DEHP. Numerous apoptotic germ cells were observed in mouse seminiferous tubules exposed to 50 and 500 mg/kg/day DEHP. Moreover, cleaved caspase-3 was elevated in mouse testes exposed to 500 mg/kg/day DEHP. In addition, Bcl-2 was reduced and Bax/Bcl-2 was elevated in mouse testes exposed to 500 mg/kg/day DEHP. Additional experiment showed that GRP78, an ER molecular chaperone, was downregulated in mouse testes exposed to 500 mg/kg/day DEHP. Testicular p-IRE-1α, p-JNK, and CHOP, three markers of ER stress, were upregulated in mice exposed to 500 mg/kg/day DEHP. These results suggest that pubertal exposure to high doses of DEHP induces germ cell apoptosis partially through initiating ER stress in testes.

In vitro evaluation of cytotoxic effects of di (2-ethylhexyl) phthalate (DEHP) produced by Bacillus velezensis strain RP137 isolated from Persian Gulf

Phthalates are widely used in polymer science and have potential toxicity related to their chemical structures. However, lots of evidence indicate that phthalate derivatives are undoubtedly produced as secondary metabolites by organisms, including plants, animals, and microorganisms. In the present study, Bacillus velezensis strain RP137 was cultured under optimized conditions. Its biomass was extracted with ethyl acetate with one fraction showing cytotoxic properties. A pure compound was isolated from the active fraction using combined silica gel and LH20 size exclusion column chromatography. Structural evaluation including FT-IR, ¹H NMR, ¹³C NMR, HR-MS and CHN analysis identified the purified compound as di(2-ethylhexyl)phthalate (DEHP) with the formula C₂₄H₃₈O₄ and the molecular weight of 389.29 Da. The microorganism-derived (stereospecific) DEHP was strongly reduced the proliferation and induced cytotoxic effects on various eukaryotic cell lines in compare to the synthetic racemic mixture of the compound when assessed by MTT assay. Furthermore, crystal violet assay and morphological changes confirmed the cytotoxic effect of DEHP. Interestingly, non-malignant SV40-immortalized fibroblast cells were less affected by the purified DEHP. Further evaluation on the antibacterial activity of DEHP documented no effect toward Gram-positive (S. aureus) and Gram-negative (E. coli and P. aeruginosa) pathogens even at a high concentration of 100 μM. In conclusion, existence of DEHP as byproduct of microorganism's metabolism can seriously be considered as a warning to human health.

Aggravation of autism-like behavior in BTBR T+tf/J mice by environmental pollutant, di-(2-ethylhexyl) phthalate: Role of nuclear factor erythroid 2-related factor 2 and oxidative enzymes in innate immune cells and cerebellum

Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder which manifests itself in early childhood and is distinguished by recurring behavioral patterns, and dysfunction in social/communication skills. Ubiquitous environmental pollutant, di-2-ethylhexyl phthalate (DEHP) is one of the most frequently used plasticizers in various industrial products, e.g. vinyl flooring, plastic toys, and medical appliances. DEHP gets easily released into the environment and leads to human exposure through various routes. DEHP has been described to be linked with oxidative stress in various organs in animal/human studies. Increased concentration of DEHP has also been detected in ASD children which indicates an association between phthalates exposure and ASD. However, effect of DEHP on autism-like behavior has not been investigated previously. Therefore, this study probed the effect of DEHP on autism-like behavior (marble burying, self-grooming and sociability) and innate immune cells (dendritic cells/neutrophils)/cerebellar oxidant-antioxidant balance (NFkB, iNOS, NADPH oxidase, nitrotyrosine, lipid peroxides, Nrf2, SOD, GPx) in BTBR and C57 mice. Our data show that DEHP treatment causes worsening of autism-like behavior in BTBR mice which is associated with enhancement of oxidative stress in innate immune cells and cerebellum with concomitant lack of antioxidant protection. DEHP also causes oxidative stress in C57 mice in both innate immune cells and cerebellar compartment, however there is Nrf2-mediated induction of enzymatic antioxidants which protects them from upregulated oxidative stress. This proposes the notion that ubiquitous environmental pollutants such as DEHP may be involved in the pathogenesis/progression of ASD through dysregulation of antioxidant-antioxidant balance in innate immune cells and cerebellum.

A novel secretagogin/ATF4 pathway is involved in oxidized LDL-induced endoplasmic reticulum stress and islet β-cell apoptosis

Excessive accumulation of cholesterol in β cells initiates endoplasmic reticulum (ER) stress and associated apoptosis. We have reported that excessive uptake of cholesterol by MIN6 cells decreases the expression of secretagogin (SCGN) and then attenuates insulin secretion. Here, we aimed to determine whether cholesterol-induced SCGN decrease is involved in the modulation of ER stress and apoptosis in pancreatic β cells. In this study, MIN6 cells were treated with oxidized low-density lipoprotein (ox-LDL) for 24 h, and then intracellular lipid droplets and cell apoptosis were quantified, and SCGN and ER stress markers were identified by western blot analysis. Furthermore, small interfer RNA (siRNA)-mediated SCGN knockdown and recombinant plasmid-mediated SCGN restoration experiments were performed to confirm the role of SCGN in ER stress and associated cell apoptosis. Finally, the interaction of SCGN with ATF4 was computationally predicted and then validated by a co-immunoprecipitation assay. We found that ox-LDL treatment increased the levels of ER stress markers, such as phosphorylated protein kinase-like endoplasmic reticulum kinase, phosphorylated eukaryotic initiation factor 2 alpha, activating transcription factor 4 (ATF4), and transcription factor CCAAT-enhancer-binding protein homologous protein, and promoted MIN6 cell apoptosis; in addition, the expression of SCGN was downregulated. siRNA-mediated SCGN knockdown exacerbated β-cell ER stress by increasing ATF4 expression. Pretreatment of MIN6 cells with the recombinant SCGN partly antagonized ox-LDL-induced ER stress and apoptosis. Furthermore, a co-immunoprecipitation assay revealed an interaction between SCGN and ATF4 in MIN6 cells. Taken together, these results demonstrated that pancreatic β-cell apoptosis induced by ox-LDL treatment can be attributed, in part, to an SCGN/ATF4-dependent ER stress response.

Developmental origins of metabolic diseases

Almost 2 billion adults in the world are overweight, and more than half of them are classified as obese, while nearly one-third of children globally experience poor growth and development. Given the vast amount of knowledge that has been gleaned from decades of research on growth and development, a number of questions remain as to why the world is now in the midst of a global epidemic of obesity accompanied by the "double burden of malnutrition," where overweight coexists with underweight and micronutrient deficiencies. This challenge to the human condition can be attributed to nutritional and environmental exposures during pregnancy that may program a fetus to have a higher risk of chronic diseases in adulthood. To explore this concept, frequently called the developmental origins of health and disease (DOHaD), this review considers a host of factors and physiological mechanisms that drive a fetus or child toward a higher risk of obesity, fatty liver disease, hypertension, and/or type 2 diabetes (T2D). To that end, this review explores the epidemiology of DOHaD with discussions focused on adaptations to human energetics, placental development, dysmetabolism, and key environmental exposures that act to promote chronic diseases in adulthood. These areas are complementary and additive in understanding how providing the best conditions for optimal growth can create the best possible conditions for lifelong health. Moreover, understanding both physiological as well as epigenetic and molecular mechanisms for DOHaD is vital to most fully address the global issues of obesity and other chronic diseases.

Effect of di(2-ethylhexyl) phthalate on Nrf2-regulated glutathione homeostasis in mouse kidney

Environmental toxicants such as phthalate have been involved in multiple health disorders including renal diseases. Oxidative damage is implicated in many alterations caused by phthalate especially the di(2-ethylhexyl) phthalate (DEHP), which is the most useful phthalate. However, information regarding its mechanism of renal damage is lacking. The transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) regulates gene expression implicated in free radical scavenging and cytoprotection including the antioxidant glutathione (GSH) pathway. The aim of this study was to assess whether DEHP affects the Nrf2 pathway and the GSH concentration. Mice were divided into four groups: a control group and three groups treated with DEHP at different concentrations (5, 50, and 200 mg/kg body weight) for 30 days. Our results showed that DEHP altered the normal levels of serum biochemical parameters creatinine (CREA), urea, and lactate dehydrogenase (LDH). This phthalate caused oxidative damage through the induction of lipid peroxidation and protein oxidation as marked by increase of protein carbonyl (PC) and loss of protein-bound sulfhydryls (PSH). Simultaneously, DEHP treatment decreased the protein level of Nrf-2, HO-1, and GCLC (responsible of GSH synthesis) and decreased the GSH level. Inhibition of the Nrf2 pathway is related to the activation of the mitochondrial pathway of apoptosis. This apoptotic process is evidenced by an upregulation of p53 and Bax protein levels in addition to a downregulation of Bcl-2. Collectively, our data demonstrated that depletion of Nrf2 and GSH was associated with the elevation of oxidative stress and the activation of intrinsic apoptosis in mouse kidney treated with DEHP.

Intrauterine exposure to low-dose DBP in the mice induces obesity in offspring via suppression of UCP1 mediated ER stress

Dibutyl phthalate (DBP) is recognized as an environmental endocrine disruptor that has been detected in fetal and postnatal samples. Recent evidence found that in utero DBP exposure was associated with an increase of adipose tissue weight and serum lipids in offspring, but the precise mechanism is unknown. Here we aimed to study the effects of in utero DBP exposure on obesity in offspring and examine possible mechanisms. SPF C57BL/6J pregnant mice were gavaged with either DBP (5 mg /kg/day) or corn oil, from gestational day 12 until postnatal day 7. After the offspring were weaned, the mice were fed a standard diet for 21 weeks, and in the last 2 weeks 20 mice were selected for TUDCA treatment. Intrauterine exposure to low-dose DBP promoted obesity in offspring, with evidence of glucose and lipid metabolic disorders and a decreased metabolic rate. Compared to controls, the DBP exposed mice had lower expression of UCP1 and significantly higher expression of Bip and Chop, known markers of endoplasmic reticulum (ER) stress. However, TUDCA treatment of DBP exposed mice returned these parameters nearly to the levels of the controls, with increased expression of UCP1, lower expression of Bip and Chop and ameliorated obesity. Intrauterine exposure of mice to low-dose DBP appears to promote obesity in offspring by inhibiting UCP1 via ER stress, a process that was largely reversed by treatment with TUDCA.

Biochemical and behavior effects induced by diheptyl phthalate (DHpP) and Diisodecyl phthalate (DIDP) exposed to zebrafish

Both Diheptyl-phthalate (DHpP) and Diisodecyl-phthalate (DIDP) were used extensively as plasticizers. Recently, their occurrence in the environmental matrices and human body fluids have been reported. Unfortunately, these phthalate congeners are without basic toxicity profiles. Hence, we studied the toxic effects of both DHpP and DIDP in the median lethal concentration (LC₅₀ 96-h) on zebrafish (Danio rerio). We assessed swimming behavior strength and tissues biomarker responses including total antioxidants capacity (TAOC), transaminases, and acetylcholinesterase (AChE) enzyme. Fish exposed to phthalate congeners (Treatment-I and-II) for 15-days showed alterations on fish swimming behavior and circadian rhythm. At the end of the exposure period, both liver and heart tissue transaminases activities were found to be accelerated in DHpP and DIDP treated fish, when compared to control group. TAOC and AChE activities were found to be decreased in brain, gills, intestine, and muscle tissues of phthalate congeners treated fish than the control group. Alterations observed in the studied biomarkers were concentration-based response. Among treatment groups DHpP showed higher effects. Comparative studies on swimming behavior and biochemical activities were reasonable to know the swimming responses are mediated due to external stress or internal stress. More studies on molecular and biomarkers assessments are warranted on toxicity of emerging contaminants.

Epigenetic repression of miR-17 contributed to di(2-ethylhexyl) phthalate-triggered insulin resistance by targeting Keap1-Nrf2/miR-200a axis in skeletal muscle

Rationale: Skeletal muscle insulin resistance is detectable before type 2 diabetes is diagnosed. Exposure to di(2-ethylhexyl) phthalate (DEHP), a typical environmental endocrine-disrupting chemical, is a novel risk factor for insulin resistance and type 2 diabetes. This study aimed to explore insulin signaling regulatory pathway in skeletal muscle of the DEHP-induced insulin-resistant mice and to investigate potential therapeutic strategies for treating insulin resistance. Methods: C57BL/6J male mice were exposed to 2 mg/kg/day DEHP for 15 weeks. Whole-body glucose homeostasis, oxidative stress and deregulated miRNA-mediated molecular transduction in skeletal muscle were examined. microRNA (miRNA) interventions based on lentiviruses and adeno-associated viruses 9 (AAV9) were performed. Results: Dnmt3a-dependent promoter methylation and lncRNA Malat1-related sponge functions cooperatively downregulated miR-17 in DEHP-exposed skeletal muscle cells. DEHP suppressed miR-17 to disrupt the Keap1-Nrf2 redox system and to activate oxidative stress-responsive Txnip in skeletal muscle. Oxidative stress upregulated miR-200a, which directly targets the 3'UTR of Insr and Irs1, leading to hindered insulin signaling and impaired insulin-dependent glucose uptake in skeletal muscle, ultimately promoting the development of insulin resistance. AAV9-induced overexpression of miR-17 and lentivirus-mediated silencing of miR-200a in skeletal muscle ameliorated whole-body insulin resistance in DEHP-exposed mice. Conclusions: The miR-17/Keap1-Nrf2/miR-200a axis contributed to DEHP-induced insulin resistance. miR-17 is a positive regulator, whereas miR-200a is a negative regulator of insulin signaling in skeletal muscle, and both miRNAs have the potential to become therapeutic targets for preventing and treating insulin resistance or type 2 diabetes.

Acute exposure to bis(2-ethylhexyl)phthalate disrupts calcium homeostasis, energy metabolism and induces oxidative stress in the testis of Danio rerio

Bis(2-ethylhexyl)phthalate (BEHP) negatively affects testicular functions in different animal species, disturbing reproductive physiology and male fertility. The present study investigated the in vitro acute effect of BEHP on the mechanism of action of ionic calcium (Ca²⁺) homeostasis and energy metabolism. In addition, the effect of BEHP on oxidative stress was studied in vitro and in vivo in the testis of Danio rerio (D. rerio). Testes were treated in vitro for 30 min with 1 μM BEHP for ⁴⁵Ca²⁺ influx measurements. Testes were also incubated with 1 μM BEHP for 1 h (in vitro) or 12 h (in vivo) for the measurements of lactate content, ¹⁴C-deoxy-d-glucose uptake, lactate dehydrogenase (LDH) and gamma-glutamyl transpeptidase (GGT) activity, total reactive oxygen species (ROS) production and lipid peroxidation. In addition, the effect of BEHP (1 μM) on GGT, glutamic oxaloacetic transferase (GOT) and glutamic pyruvic transferase (GPT) activity in the liver was evaluated after in vivo treatment for 12 h. BEHP disturbs the Ca²⁺ balance in the testis when given acutely in vitro. BEHP stimulated Ca²⁺ influx occurs through L-type voltage-dependent Ca²⁺ channels (L-VDCC), transitory receptor potential vaniloid (TRPV1) channels, reverse-mode Na⁺/Ca²⁺ exchanger (NCX) activation and inhibition of sarco/endoplasmic reticulum Ca²⁺-ATPase (SERCA). BEHP affected energy metabolism in the testis by decreasing the lactate content and LDH activity. In vitro and in vivo acute effects of BEHP promoted oxidative stress by increasing ROS production, lipid peroxidation and GGT activity in the testis. Additionally, BEHP caused liver damage by increasing GPT activity.

Mono-(2-ethylhexyl) phthalate induces oxidative stress and lipid accumulation in zebrafish liver cells

The purpose of the present study was to examine the antioxidant and oxidative stress changes in zebrafish liver (ZFL) cells in the presence of mono-(2-ethylhexyl) phthalate (MEHP). When reactive oxygen species (ROS) and antioxidant levels were measured by immunoassay, significant differences were observed between MEHP-treated and control cells, while catalase levels did not change in any group. MEHP-treated cells had higher levels of ROS, glutathione peroxidase (GPx), glutathione S-transferase (GST), glutathione, and superoxide dismutase (SOD) than control cells. However, lower levels of lipid peroxidation were observed in MEHP-treated cells compared to control cells. After 24 h of MEHP treatment, ROS, SOD, GPx, and GST activity increased in a dose-dependent manner. Cellular lipid droplet formation and endoplasmic reticulum stress were both induced in the presence of MEHP. These findings demonstrated the potential impacts of the association of MEHP with adverse outcomes in fish liver. Future studies will focus on clarifying the molecular mechanism of phthalate toxicity via oxidative stress and peroxisome proliferator activated receptor as the major mechanistic pathway.

Lycopene Prevents DEHP-Induced Leydig Cell Damage with the Nrf2 Antioxidant Signaling Pathway in Mice

As a plasticizer, di(2-ethylhexyl) phthalate (DEHP) is the most usually used phthalate. Leydig cell is a male-specific cell, which plays a principal role in spermatogenesis and masculinization by the androgens of synthesis and secretion. Numerous researchers have indicated that DEHP can result in testicular toxicity by inducing oxidative stress. Lycopene (LYC) is a possible treatment option for male infertility due to its natural antioxidant properties. Our study was aimed to investigate whether LYC could rescue DEHP-induced Leydig cell damage. The mice were treated with DEHP (500 mg/kg BW/day or 1000 mg/kg BW/day) and/or LYC (5 mg/kg BW/day) for 28 days. We found that LYC attenuated DEHP-induced Leydig cell damage. Moreover, the protective role of LYC was verified by the histopathological and ultrastructural analysis of the Leydig cell. LYC suppressed oxidative stress that was induced by DEHP. In the Leydig cell, the expressions of the nuclear factor erythroid 2-related factor 2 (Nrf2) and its downstream target genes were improved through LYC-mediated protection in DEHP-induced Leydig cell damage. Our findings indicated that LYC could increase the antioxidant capacity via mediating Nrf2 signaling pathway, thereby attenuating DEHP-induced Leydig cell damage.

Urinary biomarkers of phthalates exposure and risks of thyroid cancer and benign nodule

Phthalates have been reported to affect the function and growth of thyroid. However, there is little data on the effect of phthalates on thyroid oncogenesis. Here we explored the associations between phthalates exposure and the risks of thyroid cancer and benign nodule. We sex-matched 144 thyroid cancer, 138 benign nodule patients and 144 healthy adults from Wuhan, China. Eight phthalate metabolites in spot urine samples were quantified using high-performance liquid chromatography and tandem mass spectrometry. The associations of creatinine-corrected urinary phthalate metabolites with the risks of thyroid cancer and benign nodule were assessed using multivariable logistic regression models. We found that urinary monomethyl phthalate (MMP), mono(2-ethyl-5hydroxyhexyl) phthalate (MEHHP) and mono(2-ethylhexyl) phthalate (MEHP) associated with increased risks of thyroid cancer and nodule, with adjusted odds ratios (ORs) ranging from 1.74 to 4.78 comparing the extreme tertiles, and urinary monobutyl phthalate (MBP) was associated with decreased risks of thyroid cancer and benign nodule (all P for trends < 0.05). Male-specific positive associations of urinary monoethyl phthalate (MEP) with thyroid cancer and nodule as well as urinary mono(2-ethyl-5-oxohexyl) phthalate (MEOHP) with thyroid cancer were also observed. Our results suggest that exposure to certain phthalates may contribute to increased risks of thyroid cancer and benign nodule.

Di-2-ethylhexyl phthalate (DEHP) induces apoptosis and autophagy of mouse GC-1 spg cells

As a widely used plasticizer in industry, di-2-ethylhexylphthalate (DEHP) can cause testicular toxicity, yet little is known about the potential mechanism. In this study, DEHP exposure dramatically inhibited cellviability and induced apoptosis of mouse GC-1 spg cells. Furthermore, DEHP significantly increased the levels of autophagy proteins LC3-II, Beclin1 and Atg5, as well as the ratio ofLC3-II/LC3-I. Transmission electron microscopy (TEM) further confirmed that DEHP induced autophagy of mouse GC-1 spg cells. DEHP was also shown to induceoxidative stress; while inhibition of oxidative stress with NAC could increase cell viability and inhibit DEHP-induced apoptosis and autophagy. These results suggested that DEHP induced apoptosis and autophagy of mouse GC-1 spg cells via oxidative stress. 3-MA, an inhibitor of autophagy, could rescue DEHP-induced apoptosis. In summary, DEHP induced apoptosis and autophagy of mouse GC-1 spg cells via oxidative stress, and autophagy might exert a cytotoxic effect on DEHP-induced apoptosis.

Antidiabetic Activity of Gold Nanoparticles Synthesized Using Wedelolactone in RIN-5F Cell Line

We synthesized the gold nanoparticles (AuNPs) using wedelolactone (WDL) and characterized them using UV-visible spectroscopy, fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopic (SEM), transmission electron microscopic (TEM), energy dispersive X-ray diffraction, and atomic force microscopic (AFM) studies. The electronic spectrum exhibited an absorption peak at 535 nm. The FT-IR results proved that WDL was stabilized on the surface of AuNPs by acting as a capping or reducing agent. The crystalline structure was affirmed by XRD pattern and the spherical shape of WDL-AuNPs was evidenced by SEM, TEM, and AFM. The synthesized WDL-AuNPS were evaluated for anti-diabetic activity in pancreatic RIN-5F cell lines. In vitro results showed that WDL-AuNPs did not only improve the insulin secretion affected by di-(2-ethylhexyl) phthalate (DEHP), but also the cell viability in RIN5F cells. WDL-AuNPs treatment modulates the pro-apoptotic proteins and anti-apoptotic proteins expression to prevent the cells undergoing apoptosis in DEHP-exposed RIN-5F cells. The exposure of DEHP causes an increase in ROS production and lipid peroxidation levels. The free radical scavenging and antioxidant properties of WDL-AuNPs increase the deleterious effect caused by DEHP. On the other side, WDL-AuNPs increase mRNA expressions of insulin-signaling proteins in RIN-5F cells. This study concludes that WDL-AuNPs can be successfully used to regulate the expression of Bcl-2 family proteins, reduce lipid peroxidation, and to improve the secretion of antioxidants and insulin through the GLUT2 pathway in RIN-5F cell lines.

Di (2-ethyl hexyl) phthalate (DEHP)-induced spleen toxicity in quail (Coturnix japonica) via disturbing Nrf2-mediated defense response

Di(2-ethylhexyl) phthalate (DEHP), as a widely used plasticizer, is reported to have widespread environmental and global health hazards. Trace amounts of phthalates in the environment are sufficient to disrupt ecological balance and affect human health. However, DEHP-induced splenic toxicity remains in an unknown state. Therefore, to explore the mechanism of DEHP-induced splenic toxicity, male quail were employed with 0, 250, 500 and 750 mg/kg body weight DEHP by daily gastric perfusion for 45 days. Notably, splenic corpuscular border and cell gap enlargement were observed in the spleen tissue of DEHP-exposed quail under the histopathological analysis. Furthermore, DEHP induced dysregulation of oxidative stress markers by increasing malondialdehyde (MDA) content and decreasing superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) activities. Low concentration of DEHP (≤250 mg/kg) exposure suppressed nuclear factor-E2-related factor 2 (Nrf2) signaling pathway, while high concentration of DEHP (≥500 mg/kg) exposure activated Nrf2-mediated defense response. DEHP induced splenic oxidative stress via interfering Nrf2 signal pathway and altering the transcription of its downstream genes. In conclusion, this study suggested that DEHP induced splenic toxicity.

DEHP triggers cerebral mitochondrial dysfunction and oxidative stress in quail (Coturnix japonica) via modulating mitochondrial dynamics and biogenesis and activating Nrf2-mediated defense response

Di-(2-ethylhexyl) phthalate (DEHP) in the environment and food chain may impact cerebrum development and neurobehavioral in humans and wildlife. However, it is unclear that DEHP exposure caused cerebral toxicity. This experiment used gavage to expose female quail to 0, 250, 500, and 1000 mg/kg BW/day for 45 days to assess the potential neurotoxicity of DEHP to the cerebrum. It can be observed that there will be obvious neurological abnormalities in the experiment. Cerebrum histological lesions can be observed with HE-staining. Detecting oxidative stress indices, Nrf2 pathway, and mitochondrial dynamics factor, by analyzing the results, these results were observed that DEHP exposure can cause damage to the cerebrum by causing oxidative stress and affecting the balance of mitochondrial dynamics. Nrf2-mediated defense is not activated by exposure to 250 mg/kg DEHP. Nrf2-mediated defense is activated but is not resistant to exposure to medium and high doses of DEHP (500 mg/kg; 1000 mg/kg). DEHP triggers cerebral mitochondrial dysfunction via modulating mitochondrial dynamics.

Di-(2-Ethylhexyl) Phthalate Promotes Release of Tissue Factor-Bearing Microparticles From Macrophages via the TGFβ1/Smad/PAI-1 Signaling Pathway

BACKGROUND

Plasminogen activator inhibitor type 1 promotes formation of endothelial microparticles with procoagulant activity. However, it remains unclear whether di-(2-ethylhexyl) phthalate, a peroxisome proliferator-activated receptor α agonist, influences microparticle formation.

MATERIALS AND METHODS

The effect of di-(2-ethylhexyl) phthalate on release of tissue factor-bearing microparticles was investigated using human M1 macrophages.

RESULTS

Exposure of M1 macrophages to di-(2-ethylhexyl) phthalate significantly upregulated expression of plasminogen activator inhibitor type 1, whereas incubation of macrophages with small interfering RNA for peroxisome proliferator-activated receptor α attenuated it. Di-(2-ethylhexyl) phthalate significantly increased the tissue factor protein level in culture supernatants of M1 macrophages, but not M2 macrophages. After purification of proteins by centrifugal filtration, western blotting detected 2 high molecular weight bands of tissue factor-bearing microparticles in culture supernatants of M1 macrophages. The upper band showed binding to factor VIIa and tissue factor pathway inhibitor, unlike the lower band. This suggested heterogeneity of the procoagulant activity of tissue factor-bearing microparticles, presumably dependent upon encryption/decryption of tissue factor. Phosphatidylserine contributes to tissue factor decryption, and western blotting revealed that the density of phosphatidylserine was reduced in the upper tissue factor band compared with the lower band. Di-(2-ethylhexyl) phthalate also upregulated transforming growth factor-β1 protein production by M1 macrophages. Moreover, silencing of Smad2, Smad3 or Smad4 attenuated plasminogen activator inhibitor type 1 expression and tissue factor-release from macrophages after di-(2-ethylhexyl) phthalate stimulation.

CONCLUSIONS

Di-(2-ethylhexyl) phthalate promotes formation of tissue factor-bearing microparticles in human M1 macrophages via the transforming growth factor-β1/Smad/ plasminogen activator inhibitor type 1 signaling pathway.

Di(2-ethylhexyl) phthalate induced hepatotoxicity in quail (Coturnix japonica) via modulating the mitochondrial unfolded protein response and NRF2 mediated antioxidant defense

Among ubiquitously found environmental contaminants in the ecosystem, di(2-ethylhexyl) phthalate (DEHP) is an important environmental contaminant used as plasticizer in medical and consumer goods. The bioaccumulation and environmental persistence of DEHP cause serious global health effects in wildlife animals and human, especially hepatotoxicity. Herein, to explore the mechanisms of DEHP induced hepatotoxicity, quail were exposed with 0, 250, 500 and 1000 mg/kg BW/day DEHP by gavage administration daily for 45 days. Notably, the adipose tissue degeneration was observed in the liver of DEHP-exposed quail under the histopathological analysis. DEHP exposure increased the peroxidation product (MDA), GSH and GST, but decreased antioxidant function (T-AOC, SOD and GPX). DEHP induced the oxidative stress and pulsed on NRF2 signal pathway through activating downstream genes. Furthermore, DEHP induced mitochondrial ultrastructural abnormalities and mitochondrial dysfunctions. Mitochondrial unfolded protein response (mtUPR) was activated to relieve mitochondrial dysfunctions and mitigated oxidative stress. These findings showed that mitochondrial functions and redox homeostasis were affected by DEHP and resulted in irreversible hepatic injury. In Conclusion, this study suggested that DEHP-induced hepatotoxicity in quail was associated with activating the NRF2 mediated antioxidant defense and mtUPR. These results provided new evidence on molecular mechanism of DEHP induced hepatotoxicity.

In vitro evaluation of cytotoxic and genotoxic effects of Di(2-ethylhexyl)-phthalate (DEHP) on European sea bass (Dicentrarchus labrax) embryonic cell line

Marine litter is extensively distributed in the marine environment, and plastic debris, of which litter is mostly composed, can be a major source of pollutants. Among them, Di(2-ethylhexyl)-phthalate (DEHP) is the most abundantly used plastic additive, and it has been reported to affect biochemical processes both in humans and wildlife; however, studies on its toxicological effects on marine organisms are still scarce. In this survey, we studied the cytotoxic, genotoxic, and mutagenic effects of DEHP in European sea bass embryonic cell line (DLEC) by applying specific in vitro tests. Results showed a significant decrease in cell viability starting at 0.01 mM of DEHP after 24 h together with a significant increase in apoptosis and necrosis, morphological changes and cell detachment. Consistently, we detected a moderate increase in DNA strand breaks from 0.02 mM, and a dose-dependent increase in of micronucleus frequency from 0.01 mM, accompanied by a significant inhibition of cell proliferation, which suggested a possible aneugenic effect of this phthalate. Our results demonstrate that in vitro exposure to DEHP had a dose-dependent cytotoxic and genotoxic effects in DLEC cell line, encouraging further investigation into its effects in in vivo and/or ex vivo cell systems of marine organisms.

Role of autophagy in di-2-ethylhexyl phthalate (DEHP)-induced apoptosis in mouse Leydig cells

Di-2-ethylhexyl phthalate (DEHP) has been widely used as a plasticizer in industry. DEHP can cause testicular atrophy, yet the exact mechanism remains unclear. In this study, male mice were intragastrically (i.g.) administered with 0, 100, 200 or 400 mg DEHP/kg/day for 21 days. We found that DEHP caused disintegration of the germinal epithelium and decreased sperm density in the epididymis. Furthermore, there was a significant increase in the levels of cleaved Caspase-8, cleaved Caspase-3 and Bax proteins and a decrease in Bcl2 protein. The results indicated that DEHP could induce apoptosis of the testis tissue. Meanwhile, DEHP significantly induced autophagy in the testis tissues with increases in LC3-II, Atg5 and Beclin-1 proteins. The serum testosterone concentration decreased in the DEHP-treated group, implying that DEHP might lead to Leydig cell damage. Furthermore, oxidative stress was induced by DEHP in the testis. To further investigate the potential mechanism, mouse TM3 Leydig cells were treated with 0-80 μM DEHP for 48 h. DEHP significantly inhibited cell viability and induced cell apoptosis. Oxidative stress was involved in DEHP-induced apoptosis as N-Acetyl-L-cysteine (NAC), an inhibitor of oxidative stress, could rescue the inhibition of cell viability and induction of apoptosis by DEHP. Similar to the in vivo findings, DEHP could also induce cell autophagy. However, inhibition of autophagy by 3-Methyladenine (3-MA) significantly increased cell viability and inhibited apoptosis. Taken together, oxidative stress was involved in DEHP-induced apoptosis and autophagy of mouse TM3 Leydig cells, and autophagy might play a cytotoxic role in DEHP-induced cell apoptosis.

Involvement of oxidative stress in di-2-ethylhexyl phthalate (DEHP)-induced apoptosis of mouse NE-4C neural stem cells

Di-2-ethylhexyl phthalate (DEHP) has been widely used as a plasticizer in industry and can cause neurotoxicity; however, the underlying mechanism remains unclear. In the study, we found that DEHP significantly inhibited viability of mouse NE-4C neural stem cells and caused lactate dehydrogenase (LDH) release from the cells. DEHP dramatically increased the levels of apoptosis-related proteins such as cleaved Caspase-8, cleaved Caspase-3 and Bax, as well as decreased Bcl-2 protein level. DEHP could also significantly increase the total numbers of AnnexinV-positive/PI-negative and AnnexinV-positive/PI-positive staining cells. Hoechst 33342 staining showed that marked DNA condensation and apoptotic bodies could be found in the ZnO NPs-treated cells. These results indicated that DEHP could induce apoptosis of NE-4C cells. Meanwhile, DEHP could significantly increase malondialdehyde (MDA) level, and decrease the content of glutathione (GSH) and activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX), respectively, implying that DEHP could induce oxidative stress of NE-4C cells. Furthermore, N-Acetyl-l-cysteine (NAC), an inhibitor of oxidative stress, could rescue the inhibition of cell viability and induction of apoptosis by DEHP. Taken together, our results showed that oxidative stress was involved in DEHP-induced apoptosis of mouse NE-4C cells.