In vitro exposure to the herbicide atrazine inhibits T cell activation, proliferation, and cytokine production and significantly increases the frequency of Foxp3+ regulatory T cells

Imbalance of human CD4+ T lymphocyte subsets following atrazine treatment

While being banned in the European Union, the herbicide atrazine (ATR) is still one of the most used herbicides in the world. ATR is classified as an endocrine disruptor, but the immunotoxic effects of ATR may also be due to its direct impact on immune cells. To study the effects of ATR on human T cells, we activated T cells present in PBMCs of 8 healthy donors in the presence of ATR (0.1-100 μM). After 4 days of culture, T cells were stained to evaluate cell growth and phenotype by flow cytometry. The results demonstrated that ATR treatment exerts an antiproliferative activity on CD4+ T cells and decreases their activation, including the percentage of cytokine-producing CD4+ T cells. Among these, the percentage of interferon (IFN)-γ- and interleukin (IL)-22-producing CD4+ T cells decreased within total CD4+ T cells. Moreover, IL-4-, IL-10- and IL-17-producing CD4+ T cells decreased within cytokine-producing CD4+ T cells. Consequently, ATR caused a dose-related decrease in Th1/Th2 ratio. Many of the effects of ATR treatment were quantitatively different in males and females, with more pronounced effects observed in females. tSNE analysis demonstrated that ATR strongly inhibited the differentiation of two subsets of IFN-γ+IL-4+CD4+ T cells from each of the healthy donors tested and promoted greater differentiation of the CD25+FoxP3+CD4+ T cell subset from seven out of the eight healthy donors tested. In conclusion, the study suggests that ATR skews CD4+ T cell activation towards Th2, a phenotype that may promote reduced immunosurveillance and increased risk of cancer, as well as Th2-related diseases such as asthma, thereby presenting an environmental and occupation-related risk to human health.

Atrazine's effects on mammalian physiology

Atrazine is a chlorotriazine herbicide that is one of the most widely used herbicides in the USA and the world. For over 60 years atrazine has been used on major crops including corn, sorghum, and sugarcane to control broadleaf and grassy weed emergence and growth. Atrazine has exerted a major economic and environmental impact over that time, resulting in reduced production costs and increased conservation tillage practices. However, widespread use and a long half-life led to a high prevalence of atrazine in the environment. Indeed, atrazine is the most frequent herbicide contaminant detected in water sources in the USA. Due to its almost ubiquitous presence and questions regarding its safety, atrazine has been well-studied. First reported to affect reproduction with potential disruptive effects which were later linked to the immune system, cancer, stress response, neurological disorders, and cardiovascular ailments in experimental models. Atrazine impact on multiple interwoven systems broadens the significance of atrazine exposure. The endeavor to uncover the mechanisms underlying atrazine-induced dysfunction in mammals is ongoing, with new genetic and pharmacological targets being reported. This review aims to summarize the prominent effects of atrazine on mammalian physiology, primarily focusing on empirical studies conducted in lab animal models and establish correlations with epidemiological human studies when relevant. In addition, current common patterns of toxicity and potential underlying mechanisms of atrazine action will be examined.

The ENDOMIX perspective: how everyday chemical mixtures impact human health and reproduction by targeting the immune system†

Endocrine-disrupting chemicals are natural and synthetic compounds found ubiquitously in the environment that interfere with the hormonal-immune axis, potentially impacting human health and reproduction. Exposure to endocrine-disrupting chemicals has been associated with numerous health risks, such as neurodevelopmental disorders, metabolic syndrome, thyroid dysfunction, infertility, and cancers. Nevertheless, the current approach to establishing causality between these substances and disease outcomes has limitations. Epidemiological and experimental research on endocrine-disrupting chemicals faces challenges in accurately assessing chemical exposure and interpreting non-monotonic dose response curves. In addition, most studies have focused on single chemicals or simple mixtures, overlooking complex real-life exposures and mechanistic insights, in particular regarding endocrine-disrupting chemicals' impact on the immune system. The ENDOMIX project, funded by the EU's Horizon Health Program, addresses these challenges by integrating epidemiological, risk assessment, and immunotoxicology methodologies. This systemic approach comprises the triangulation of human cohort, in vitro, and in vivo data to determine the combined effects of chemical mixtures. The present review presents and discusses current literature regarding human reproduction in the context of immunotolerance and chemical disruption mode of action. It further underscores the ENDOMIX perspective to elucidate the impact of endocrine-disrupting chemicals on immune-reproductive health.

Pesticide residues: Bridging the gap between environmental exposure and chronic disease through omics

Pesticide residues, resulting from agricultural practices, pose significant health and environmental risks. This review synthesizes the current understanding of pesticide impacts on the immune system, highlighting their role in chronic diseases such as asthma, diabetes, Parkinson's disease (PD) and cancer. We emphasize the significant role of omics technologies in the study of pesticide toxicity mechanisms. The integration of genomics, proteomics, metabolomics, and epigenomics offers a multidimensional strategy for a comprehensive assessment of pesticide effects, facilitating personalized risk management and policy formulation. We advocate for stringent regulatory policies, public education, and global cooperation to enhance food safety and environmental sustainability. By adopting a unified approach, we aim to mitigate the risks of pesticide residues, ensuring human health and ecological balance are preserved.

Atrazine promotes cholangiocarcinoma cell proliferation and migration via GPER-mediated PI3K/Akt/NF-κB pathway

Atrazine (ATZ), an herbicide widely distributed on a global scale, possess a potential risk for the development of various cancers upon environmental exposure. However, the effect and molecular mechanism of ATZ in cholangiocarcinoma (CCA), is still unclear. This study aimed to investigate the effect of ATZ on the proliferation and migration of CCA cell in vitro. Immortalized human cholangiocytes (MMNK-1) and three CCA cell lines (KKU-055, KKU-100 and KKU-213B) were treated with 0.01 to 100 μM of ATZ and 17β-estradiol (E2). The results showed that, similar to E2, low doses (0.01 to 1 μM) of ATZ promoted the proliferation of all CCA and MMNK-1 cells. ATZ exposure increased non-genomic G protein-coupled estrogen receptor (GPER) expression in the cell membrane and cytoplasm of KKU-213B and KKU-055 cells via G2/M cell cycle accumulation. This, in turn, promoted the proliferation and migration of CCA cells. ATZ exposure induced the upregulation of GPER and increased expression levels of PI3K, p-PI3K, Akt, p-Akt, NF-κB and PCNA. In contrast, following ATZ treatment, the GPER antagonist G15 significantly downregulated the GPER/PI3K/Akt/NF-κB pathway. These results suggest that ATZ promotes CCA cell proliferation and migration through the GPER/PI3K/Akt/NF-κB pathway. This information can enhance public health awareness regarding ATZ contamination to prevent the relative risk of CCA.

Lycopene Protects against Atrazine-Induced Kidney STING-Dependent PANoptosis through Stabilizing mtDNA via Interaction with Sam50/PHB1

Atrazine (ATR) is a widely used herbicide worldwide that can cause kidney damage in humans and animals by accumulation in water and soil. Lycopene (LYC), a carotenoid with numerous biological activities, plays an important role in kidney protection due to its potent antioxidant and anti-inflammatory effects. The current study sought to investigate the role of interactions between mtDNA and the cGAS-STING signaling pathway in LYC mitigating PANoptosis and inflammation in kidneys induced by ATR exposure. In our research, 350 mice were orally administered LYC (5 mg/kg BW/day) and ATR (50 or 200 mg/kg BW/day) for 21 days. Our results reveal that ATR exposure induces a decrease in mtDNA stability, resulting in the release of mtDNA into the cytoplasm through the mPTP pore and the BAX pore and the mobilization of the cGAS-STING pathway, thereby inducing renal PANoptosis and inflammation. LYC can inhibit the above changes caused by ATR. In conclusion, LYC inhibited ATR exposure-induced histopathological changes, renal PANoptosis, and inflammation by inhibiting the cGAS-STING pathway. Our results demonstrate the positive role of LYC in ATR-induced renal injury and provide a new therapeutic target for treating renal diseases in the clinic.

Atrazine: cytotoxicity, oxidative stress, apoptosis, testicular effects and chemopreventive Interventions

Atrazine (ATZ) is an environmental pollutant that interferes with several aspects of mammalian cellular processes including germ cell development, immunological, reproductive and neurological functions. At the level of human exposure, ATZ reduces sperm count and contribute to infertility in men. ATZ also induces morphological changes similar to apoptosis and initiates mitochondria-dependent cell death in several experimental models. When in vitro experimental models are exposed to ATZ, they are faced with increased levels of reactive oxygen species (ROS), cytotoxicity and decreased growth rate at dosages that may vary with cell types. This results in differing cytotoxic responses that are influenced by the nature of target cells, assay types and concentrations of ATZ. However, oxidative stress could play salient role in the observed cellular and genetic toxicity and apoptosis-like effects which could be abrogated by antioxidant vitamins and flavonoids, including vitamin E, quercetin, kolaviron, myricetin and bioactive extractives with antioxidant effects. This review focuses on the differential responses of cell types to ATZ toxicity, testicular effects of ATZ in both in vitro and in vivo models and chemopreventive strategies, so as to highlight the current state of the art on the toxicological outcomes of ATZ exposure in several experimental model systems.

Atrazine promotes breast cancer development by suppressing immune function and upregulating MMP expression

There is evidence that the triazine herbicide atrazine, which is used extensively, is present in both surface water and groundwater, and its interfering effect on immune systems, endocrine systems, and tumours has been reported by laboratory and epidemiological studies. This study explored how atrazine affected 4T1 breast cancer cell development in vitro and in vivo. The obtained results showed that after exposure to atrazine, the cell proliferation and tumour volume were significantly increased and the expression of MMP2, MMP7, and MMP9 was upregulated. The thymus and spleen indices, the CD4 + and CD3 + lymphocyte percentages which from the spleen and inguinal lymph nodes, and the CD4 + /CD8 + ratio were noticeably lower than they were in the control group. Importantly, tumour-infiltrating lymphocytes such as CD4 + , CD8 + , and NK cells were decreased while Treg cells were increased. Moreover, IL-4 was increased and IFN-γ and TNF-α were decreased in the serum and tumour microenvironment. These results suggested that atrazine can suppress systemic as well as local tumour immune function and upregulate MMPs to promote breast tumour development.

Toxic effects of pesticides on cellular and humoral immunity: an overview

People are exposed to pesticides through food, drinking water, and the environment. These compounds are associated with several disorders, such as inflammatory diseases, rheumatoid arthritis, cancer, and a condition related to metabolic syndrome. The immunotoxicants or immunotoxic compounds can cause a wide variety of effects on immune function, altering humoral immunity and cell-mediated immunity, resulting in adverse effects to the body. Here, immune system disorders are highlighted because they are closely linked to multiple organs, including the nervous, endocrine, reproductive, cardiovascular, and respiratory systems, leading to transient or permanent changes. Therefore, this study reviewed the mechanisms involved in the immunotoxicity of fungicides, herbicides, and insecticides in cells, animals, and humans in the past 11 years. According to the studies analyzed, the pesticides interfere with innate and adaptive immune functions, but the effects observed mainly on cellular and humoral immunity were highlighted. These compounds affected specific immune cells, causing apoptosis, changes in factor nuclear kappa B (NF-κB) expression, pro-inflammatory factors interleukin 6 (IL-6), interleukin 8 (IL-8), interferon-gamma (IFN-γ), chemokines (CXCL-c1c), and anti-inflammatory factor, such as interleukin 10 (IL-10). To verify the threats of these compounds, new evaluations with immunotoxicological biomarkers are necessary. HighlightsPesticides interfere with the innate and adaptive immune response.Cells, animals and human studies demonstrate the immunotoxicity of pesticides in the cellular and humoral immune response.Fungicides, herbicides, and insecticides alter the immune system by various mechanisms, such as pro-inflammatory and anti-inflammatory factors.

Effects of endocrine active contaminating pesticides on RACK1 expression and immunological consequences in THP-1 cells

We have previously demonstrated that RACK1, which expression is under steroid hormone control, plays an important role in the activation of immune cells and its expression can be useful to evaluate the immunotoxic profile of endocrine disrupting chemicals (EDCs). Hence, we investigated the effects of three contaminating and persistent pesticides: the fungicide vinclozolin (VIN), the herbicide atrazine (ATR) and the insecticide cypermethrin (CYP) on RACK1 expression and on innate immune response. VIN resulted in modest alteration of RACK1 while ATR and CYP reduced in a dose dependent manner RACK1 expression, ultimately leading to the decrease in lipopolysaccharide-induced IL-8 and TNF-α release and CD86 and CD54 surface marker expression. Moreover, our data indicate that, after exposure to EDCs, alterations of RACK1 expression can also occur with mechanisms not directly mediated by an interaction with a nuclear or membrane steroid receptors. Therefore, RACK1 could represent a useful EDCs screening tool to evaluate their immunotoxic potential and to dissect their mechanisms of action.

Curcumin improves the protective effects of quercetin against atrazine-induced testicular injury in adult Wistar rats

This study evaluated the beneficial protective effect of cotreatment of curcumin (CUR) and quercetin (QUE) on atrazine (ATZ)-induced testicular toxicity in rats. ATZ challenge diminished luteinizing hormone, follicular stimulating hormone, testosterone and myeloperoxidase enzyme activity, but these effects were attenuated on co-treatment with CUR and QUE. Also, co-treatment of CUR + QUE was better than separate administration of QUE at diminishing malondialdehyde and glutathione and improving tumour necrosis factor-α concentration, germ cell numbers (spermatogonia, spermatocytes and round spermatids) and epididymal sperm quality. Histologically, smaller sized tubules with degenerated epithelia and few germ cells were seen in the seminiferous tubules of the ATZ group whereas CUR + QUE pretreatment improved the histo-morphologic features of the tubules compared to the ATZ group and was also better than separate administration of QUE. We conclude that CUR can improve the protective effects of QUE against ATZ-induced testicular injury by enhancing the levels of reproductive hormones, recovering testicular biochemical parameters and improving the histological features of the testes.

Endocrine Disruptor Compounds-A Cause of Impaired Immune Tolerance Driving Inflammatory Disorders of Pregnancy?

Endocrine disrupting compounds (EDCs) are prevalent and ubiquitous in our environment and have substantial potential to compromise human and animal health. Amongst the chronic health conditions associated with EDC exposure, dysregulation of reproductive function in both females and males is prominent. Human epidemiological studies demonstrate links between EDC exposure and infertility, as well as gestational disorders including miscarriage, fetal growth restriction, preeclampsia, and preterm birth. Animal experiments show EDCs administered during gestation, or to either parent prior to conception, can interfere with gamete quality, embryo implantation, and placental and fetal development, with consequences for offspring viability and health. It has been presumed that EDCs operate principally through disrupting hormone-regulated events in reproduction and fetal development, but EDC effects on maternal immune receptivity to pregnancy are also implicated. EDCs can modulate both the innate and adaptive arms of the immune system, to alter inflammatory responses, and interfere with generation of regulatory T (Treg) cells that are critical for pregnancy tolerance. Effects of EDCs on immune cells are complex and likely exerted by both steroid hormone-dependent and hormone-independent pathways. Thus, to better understand how EDCs impact reproduction and pregnancy, it is imperative to consider how immune-mediated mechanisms are affected by EDCs. This review will describe evidence that several EDCs modify elements of the immune response relevant to pregnancy, and will discuss the potential for EDCs to disrupt immune tolerance required for robust placentation and optimal fetal development.

Adverse effects of pesticides on the functions of immune system

Pesticides are chemical substances used to kill unwanted fungi, weeds and insects. In many countries, there is currently concern regarding the adverse effects of pesticides on health. It has been reported that pesticides may cause cancer, respiratory diseases, organ diseases, system failures, nervous system disorders and asthma, which are closely connected with immune disorders. Therefore, this study reviewed the immunotoxicity of pesticides that are currently used or prohibited from being used, especially their effects on leukocytes such as T cells, B cells, NK cells and macrophages. These immune cells play crucial roles in innate and adaptive immune systems to protect hosts. Pesticides are known to have possible toxicological modes of action to induce oxidative stress, mitochondrial dysfunction, and endoplasmic reticulum (ER) stress in living organisms. According to previous studies, pesticides such as atrazine (ATR), organophophorus (OP) compounds, carbamates, and pyrethroids were shown to inhibit the survival and growth of leukocytes by inducing apoptosis or cell cycle arrest and interfering with the specific immunological functions of each type of immune cells. These results suggest the immunotoxicity of pesticides toward specific immune cells. To substantiate the overall immunocompromised effects of pesticides, there is a need to collect and thoroughly analyze additional information regarding other immunological toxicities.

Assessing in vitro and in vivo Trogocytosis By Murine CD4+ T cells

Recognition of antigens by lymphocytes (B, T, and NK) on the surface of an antigen-presenting cell (APC) leads to lymphocyte activation and the formation of an immunological synapse between the lymphocyte and the APC. At the immunological synapse APC membrane and associated membrane proteins can be transferred to the lymphocyte in a process called trogocytosis. The detection of trogocytosed molecules provides insights to the activation state, antigen specificity, and effector functions and differentiation of the lymphocytes. Here we outline our protocol for identifying trogocytosis-positive CD4+ T cells in vitro and in vivo. In vitro, antigen presenting cells are surface biotinylated and pre-loaded with magnetic polystyrene beads before incubating for a short time with in vitro activated CD4+ T cell blasts (90 min) or naïve T cells (3-24 h). After T cell recovery and APC depletion by magnetic separation trogocytosis positive (trog+) cells are identified by streptavidin staining of trogocytosed, biotinylated APC membrane proteins. Their activation phenotype, effector function, and effector differentiation are subsequently analyzed by flow cytometry immediately or after subsequent incubation. Similarly, trogocytosis-positive cells can be identified and similarly analyzed by flow cytometry. Previous studies have described methods for analyzing T cell trogocytosis to identify antigen-specific cells or the antigenic epitopes recognized by the cells. With the current protocol, the effects of trogocytosis on the individual T cell or the ability of trog+ T cells to modulate the activation and function of other immune cells can be assessed over an extended period of time.

Glycyrrhizic acid modulates the atrazine-induced apoptosis in rabbit spleen

Atrazine (ATR) is a common herbicide used worldwide. It is a potent endocrine disruptor that causes hormonal imbalance. We investigated the modulatory role predisposed by glycyrrhizic acid (GA) against the hazardous effects caused by the ATR in the rabbit spleen. Sixty rabbits were assigned into 4 groups. The first group is the negative control; the ATR group received 1/10 of the oral LD ₅₀ ATR; the GA group received 50 mg/kg body weight daily intraproteinally; and group 4 received both ATR and GA concurrently. ATR and GA administrations were done for 60 days. ATR-induced humoral immunotoxicity was illustrated by decreased serum total protein, albumin, and globulin levels and rabbit hemorrhagic disease virus antibody titer, 4 weeks after vaccination. Moreover, upregulation of spleen Fas and caspase-III genes was recorded in ATR-exposed rabbits. Clear splenocyte apoptosis was observed in the immunohistochemical examination by the caspase-III technique. GA diminished the ATR-induced splenocyte apoptosis through downregulation of Fas and caspase-III expressions. In conclusion, our findings bounced a new perspective into the mechanism by which ATR induces immunotoxicity and assumed the potential modulatory role of GA.

Immunomodulatory effects of synthetic endocrine disrupting chemicals on the development and functions of human immune cells

Endocrine disrupting chemicals (EDCs) are added to food, cosmetics, plastic packages, and children's toys and have thus become an integral part of the human environment. In the last decade, there has been increasing interest in the effect of EDCs on human health, including their impact on the immune system. So far, researchers have proved that EDCs (e.g. bisphenols, phthalates, triclosan, phenols, propanil, tetrachlorodibenzo-p-dioxin, diethylstilbestrol, tributyltin (TBT), and parabens) affect the development, functions, and lifespan of immune cells (e.g., monocytes, neutrophils, mast cells, eosinophils, lymphocytes, dendritic cells, and natural killers). In this review, we have summarized the current knowledge of the multivariable influence of EDCs on immune cells and underlined the novel approach to EDC studies, including dose-dependent effects and low-dose effects. We discuss critically the possible relationship between exposure to EDCs and immunity related diseases (e.g. allergy, asthma, diabetes, and lupus). Moreover, based on the literature, we construct a model of possible mechanisms of EDC action on immune cells at cellular, molecular, and epigenetic levels.

A novel mechanism underlies atrazine toxicity in quails (Coturnix Coturnix coturnix): triggering ionic disorder via disruption of ATPases

The widely used atrazine has been reported to exhibit extensive ecological hazards. Due to the biological accumulation, atrazine elicits widespread toxic effects on different organisms. However, true proof for the mechanism of atrazine-induced toxicity is lacking. To determine the potential mechanism by which atrazine exerted toxic effects, quails were treated with atrazine (0, 50, 250 and 500 mg/kg) by gavage administration for 45 days. Atrazine significantly increased the histological alterations and serum creatine kinase, lactate dehydrogenase and choline esterase levels. A marked disorder in ionic (Na+, K+, Ca2+ and Mg2+)contents and the decrease of ATPases (Na+-K+-ATPase, Ca2+-ATPase, Mg2+-ATPase and Ca2+-Mg2+-ATPase) activities were observed in the heart and liver of atrazine-exposed quails. Of note, it was also observed that atrazine suppressed the transcription of Na+, K+ transfer associated genes (Na+-K+-ATPase subunits) and Ca2+ transfer associated genes (Ca2+-ATPase subunits, solute carriers) in heart and liver. In conclusion, atrazine induced cardiac and hepatic damage via causing the ionic disorder, triggering the transcription of the ion transporters and leading the histopathological and functional alternations in the heart and liver of quails. This study demonstrated atrazine significantly induced the ionic disorder via decreasing the ATPases activities and disturbing the transcription of the ion transporters.

Lack of immunotoxic effects of repeated exposure to atrazine associated with the adaptation of adrenal gland activation

T cell-dependent IgM antibody production and natural killer cell (NKC) activity were assessed in SD rats orally administered atrazine for 28 days to males (0, 6.5, 25, or 100 mg/kg/day) or females (0, 3, 6, or 50 mg/kg/day), or 30 or 500 ppm in diet (3 or 51 mg/kg/day). Anti-asialo GM1 antibodies (NKC) and cyclophosphamide (antibody-forming cell assay [AFC]) served as positive controls. Pituitary (ACTH, prolactin), adrenal (corticosterone, progesterone, aldosterone), and gonadal (androgens, estrogens) hormones were assessed after 1, 7, and/or 28 days of treatment. Food intake and body weights were significantly reduced in the highest dosed males, and transiently affected in females. Urinary corticosterone levels were not increased in atrazine-treated groups in either sex at any time point measured (10, 22, or 24 days). Corticosterone and progesterone were elevated in males after a single atrazine dose ≥6.5 mg/kg/day, but not after 7, 14, or 28 doses. There were no effects on adrenal, pituitary, or gonadal hormones in females. Atrazine did not suppress the AFC response or decrease NKC function after 28 days in males or females. Atrazine had no effect on spleen weights or spleen cell numbers in males or females, although thymus weights were elevated in males receiving the highest dose. The lack of immunotoxic effect of atrazine was associated with diminished adrenal activation over time in males, and no effects on adrenal hormones in females.

Toxic effects of atrazine on porcine oocytes and possible mechanisms of action

Because atrazine is a widely used herbicide, its adverse effects on the reproductive system have been extensively researched. In this study, we investigated the effects of atrazine exposure on porcine oocyte maturation and the possible mechanisms. Our results showed that the rates of oocyte maturation significantly decreased after treatment with 200 μM atrazine in vitro. Atrazine treatment resulted in abnormal spindle morphology but did not affect actin distribution. Atrazine exposure not only triggered a DNA damage response but also decreased MPF levels in porcine oocytes. Our results also revealed that atrazine worsened porcine oocyte quality by causing excessive accumulation of superoxide radicals, increasing cathepsin B activity, and decreasing the GSH level and mitochondrial membrane potential. Furthermore, atrazine decreased developmental competence of porcine oocytes up to the blastocyst stage and changed some properties: cell numbers, apoptosis, and related gene expression levels. Collectively, our results indicate that porcine oocyte maturation is defective after atrazine treatment at least through disruption of spindle morphology, MPF activity, and mitochondrial function and via induction of DNA damage, which probably reduces developmental competence.

Potential biomarkers for monitoring the toxicity of long-term exposure to atrazine in rat by metabonomic analysis

1. Herbicide atrazine (ATR) poses harmful effects on human health. The purpose of this study is to study potential biomarkers used for monitoring the toxic effects after chronic exposure to ATR by studying urine metabolites. 2. Rats were assigned into clinical chemistry and metabonomics arms, and each arm was divided into low-dose, high-dose and control groups. ATR was administered to rats along with their feed. At the end of 16, 20 and 24 weeks, clinical parameters and histopathologic changes was assessed to monitor the toxic effects. Twenty-four hour urine samples was analyzed by UPLC-MS, to find the significant alterations in metabolic profiling. 3. The body weight of rats in ATR group was lower than that of control starting from 12th week; abnormal levels of serum biochemistry and histopathologic alterations of organs were found initially from 16th and 20th week, respectively. Five exogenous and five endogenous metabolites were found which showed significant differences between ATR groups and control group at above-mentioned time points. 4. These metabolites may be used as potential indicators to monitor ATR toxicity, and also may provide some clues for understanding the mechanism of toxicity of ATR. The exact relationship between endogenous metabolites and ATR toxicity needs further investigation.

Effects of long-term endocrine disrupting compound exposure on Macaca mulatta embryonic stem cells

Endocrine disrupting chemicals (EDCs) exert significant effects on health and physiology, many traceable to effects on stem cell programming underlying development. Understanding risk of low-level, chronic EDC exposure will be enhanced by knowledge of effects on stem cells. We exposed rhesus monkey embryonic stem cells to low levels of five EDCs [bisphenol A (BPA), atrazine (ATR), tributyltin (TBT), perfluorooctanoic acid (PFOA), and di-(2-ethylhexyl) phthalate (DEHP)] for 28days, and evaluated effects on gene expression by RNAseq transcriptome profiling. We observed little effect of BPA, and small numbers of affected genes (≤119) with other EDCs. There was substantial overlap in effects across two, three, or four treatments. Ingenuity Pathway analysis indicated suppression of cell survival genes and genes downstream of several stress response mediators, activation of cell death genes, and modulations in several genes regulating pluripotency, differentiation, and germ layer development. Potential adverse effects of these changes on development are discussed.

Assessing the carcinogenic potential of low-dose exposures to chemical mixtures in the environment: the challenge ahead

Lifestyle factors are responsible for a considerable portion of cancer incidence worldwide, but credible estimates from the World Health Organization and the International Agency for Research on Cancer (IARC) suggest that the fraction of cancers attributable to toxic environmental exposures is between 7% and 19%. To explore the hypothesis that low-dose exposures to mixtures of chemicals in the environment may be combining to contribute to environmental carcinogenesis, we reviewed 11 hallmark phenotypes of cancer, multiple priority target sites for disruption in each area and prototypical chemical disruptors for all targets, this included dose-response characterizations, evidence of low-dose effects and cross-hallmark effects for all targets and chemicals. In total, 85 examples of chemicals were reviewed for actions on key pathways/mechanisms related to carcinogenesis. Only 15% (13/85) were found to have evidence of a dose-response threshold, whereas 59% (50/85) exerted low-dose effects. No dose-response information was found for the remaining 26% (22/85). Our analysis suggests that the cumulative effects of individual (non-carcinogenic) chemicals acting on different pathways, and a variety of related systems, organs, tissues and cells could plausibly conspire to produce carcinogenic synergies. Additional basic research on carcinogenesis and research focused on low-dose effects of chemical mixtures needs to be rigorously pursued before the merits of this hypothesis can be further advanced. However, the structure of the World Health Organization International Programme on Chemical Safety 'Mode of Action' framework should be revisited as it has inherent weaknesses that are not fully aligned with our current understanding of cancer biology.