Endosulfan decreases cell growth and apoptosis in human HaCaT keratinocytes: partial ROS-dependent ERK1/2 mechanism

Toxicity evaluation of Pinus radiata D.Don bark wax for potential cosmetic application

Radiata pine bark is a widely available organic waste, requiring alternative uses due to its environmental impact on soil, fauna, and forest fires. Pine bark waxes could be used as cosmetic substitutes, but their toxicity requires evaluation since pine bark may contain toxic substances or xenobiotics, depending on the extraction process. This study evaluates the toxicity of radiata pine bark waxes obtained through various extraction methods on human skin cells grown in vitro. The assessment includes using XTT to evaluate mitochondrial activity, violet crystal dye to assess cell membrane integrity, and ApoTox-Glo triple assay to measure cytotoxicity, viability, and apoptosis signals. Pine bark waxes extracted via T3 (acid hydrolysis and petroleum ether incubation) and T9 (saturated steam cycle, alkaline hydrolysis, and petroleum ether incubation) exhibit non-toxicity up to 2% concentration, making them a potential substitute for petroleum-based cosmetic materials. Integrating the forestry and cosmetic industries through pine bark wax production under circular economy principles could promote development while replacing petroleum-based materials. Extraction methodology affects pine bark wax toxicity in human skin cells due to the retention of xenobiotic compounds including methyl 4-ketohex-5-enoate; 1-naphthalenol; dioctyl adipate; eicosanebioic acid dimethyl ester; among others. Future research will investigate whether the extraction methodology alters the molecular structure of the bark, affecting the release of toxic compounds in the wax mixture.

Risk of genotoxic damage in schoolchildren exposed to organochloride pesticides

This study identified and determined organochloride pesticide (OCs) concentrations in hair samples from children at two elementary schools: one exposed to fumigations in agricultural fields, the other unexposed. Three concentrations of OCs levels in the hair were compared (high, medium, low), and total nuclear abnormalities in buccal cells were determined: micronuclei (MNi), condensed chromatin, karyorrhexis, pyknosis, binucleate cells, karyolysis, lobed nuclei, and apoptosis. No significant differences were found for the presence of MNi between the schoolchildren from the exposed and unexposed schools, but the prevalence of OCs in both schools was over 50%, as well as the frequencies of MNi in the children were over 58%. Findings show a significant difference between the frequency of MNi in the total sample of schoolchildren (exposed school + unexposed school) in relation to the concentration of OCs detected in their hair. The children from exposed school that showed the higher concentrations of OCs in hair had higher levels of genotoxic damage in the buccal cells; compared against children with lower concentrations of OCs. The most frequent nuclear abnormalities in the exposed children were lobed nuclei (79.4%), binucleate cells (66.66%), apoptosis (65.07), and MNi (58.7%). We determined the prevalence ratio (PR) and prevalence odds ratio (POR) for the presence of MNi in buccal cells in relation to the OCs concentrations in the hair samples. Both ratios were high for MNi [PR 3.93, 95% confidence interval (CI) 1.97–7.84, p = 0.0003; and POR 7.97, 95% CI 2.62–24.28, p = 0.0003], indicating a 7.97 times greater risk that the exposed children will present > 0.2% of MNi when OCs concentrations exceed 0.447 μg/g. These indicators may be useful biomarkers of genotoxic damage in children exposed to persistent, highly-toxic compounds. Results suggest the potential risk to which those schoolchildren are exposed on a daily basis due to fumigations in nearby agricultural fields.

p,p'-Dichlorodiphenyltrichloroethane promotes aerobic glycolysis via reactive oxygen species-mediated extracellular signal-regulated kinase/M2 isoform of pyruvate kinase (PKM2) signaling in colorectal cancer cells

Aerobic glycolysis is crucial to tumor cells to acquire energy for proliferation and metastasis. Dichlorodiphenyltrichloroethane (DDT), which is a persistent organic pollutant, has been associated with colorectal cancer (CRC) progressions, but the influence of p,p'-DDT on CRC cell metabolism remains unclear. This study showed that exposure to low concentrations of p,p'-DDT from 10^-11 to 10^-7 M for 48 hours significantly increased glucose uptake and lactate production in colorectal adenocarcinoma cells, which were accompanied by the upregulation of proteins associated with aerobic glycolysis including glucose transporter1, lactate dehydrogenase A, and PDH kinase. We found p,p'-DDT elevated the expression and nucleus translocation of M2 isoform of pyruvate kinase (PKM2), which was responsible for p,p'-DDT-induced enhancement of aerobic glycolysis. Moreover, extracellular signal-regulated kinase (ERK1/2) activation by p,p'-DDT modulated the impacts of p,p'-DDT on PKM2 and aerobic glycolysis. Treatment of p,p'-DDT increased intracellular reactive oxygen species (ROS). N-acetyl-L-cysteine, an ROS inhibitor, prevented p,p'-DDT-induced promotion of aerobic glycolysis, ERK1/2 activation, upregulation, and nucleus translocation of PKM2. Taken together, these results demonstrated that p,p'-DDT promotes aerobic glycolysis via ROS-mediated ERK/PKM2 signaling.

Potential Health Risks Linked to Emerging Contaminants in Major Rivers and Treated Waters

The presence of endocrine-disrupting chemicals (EDCs) in our local waterways is becoming an increasing threat to the surrounding population. These compounds and their degradation products (found in pesticides, herbicides, and plastic waste) are known to interfere with a range of biological functions from reproduction to differentiation. To better understand these effects, we used an in silico ontological pathway analysis to identify the genes affected by the most commonly detected EDCs in large river water supplies, which we grouped together based on four common functions: Organismal injuries, cell death, cancer, and behavior. In addition to EDCs, we included the opioid buprenorphine in our study, as this similar ecological threat has become increasingly detected in river water supplies. Through the identification of the pleiotropic biological effects associated with both the acute and chronic exposure to EDCs and opioids in local water supplies, our results highlight a serious health threat worthy of additional investigations with a potential emphasis on the effects linked to increased DNA damage.

Low-dose endosulfan inhibits proliferation and induces senescence and pro-inflammatory cytokine production in human lymphocytes, preferentially impacting cytotoxic cells

Endosulfan is a DDT-era organochlorine pesticide. Due to past and current environmental contamination, investigation of endosulfan exposure is of current importance. Acute high dose exposure precipitates neural/endocrine system damage, but the effects on the immune system and of lower doses are not well-characterized. Two relatively low concentrations of endosulfan (i.e. 0.1 and 17 µM ENDO) were investigated in an in vitro study using human peripheral blood mononuclear cells (PBMC) to understand effects of relatively low doses (0.1-25.0 µM [≈0.04-10 ppm/40-10,000 ppb]) of ENDO upon normal human T- and B-lymphocytes and NK cells. The study here found that 17 µM ENDO inhibited phytohemagglutinin-M (PHA)-induced human PBMC proliferation. It was also seen that senescence and apoptosis among non-stimulated cells was increased, specifically within CD8 and NK populations, and that CD4:CD8 ratios also were increased. Treatment of non-stimulated PBMC with ENDO led to overall increases in production of tumor necrosis factor (TNF)-α, interferon (IFN)-γ, interleukin (IL)-2, -4, and -6, and decreased production of anti-inflammatory IL-10, suggesting an immunosenescence secretory phenotype. Interestingly, when the cells were pre-stimulated with mitogen (PHA), ENDO became inhibitory against the mitogen-induced proliferation and cytokine formation - with the exception of that of TNFα and IL-6, suggesting differential effects of ENDO on activated cells. Thus, at the organismal level, ENDO might also display differential effects during states of autoimmune disease or chronic viral infection in the exposed host.

Oleanolic acid protects against oxidative stress‑induced human umbilical vein endothelial cell injury by activating AKT/eNOS signaling

Oxidative injury of vascular endothelial cells in the initial event of atherosclerosis (AS) in diabetes was assessed in the present study. The antioxidant effect of oleanolic acid (OA) has attracted much attention. In the present study the potential effects of OA on human umbilical vein endothelial cells (HUVECs) were investigated. Cell viability was examined using the CCK‑8 assay. The activity of oxidative stress parameters was determined using commercial kits. Flow cytometry analysis was performed to detect the level of reactive oxygen species (ROS), mitochondrial membrane potential (MMP) and cell apoptosis. The expression levels of target genes and proteins were examined by reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) and western blot analysis. It was indicated that cell viability that was suppressed by high glucose was increased by the pretreatment of OA, and nitric oxide (NO) generation, the activities of superoxide dismutase (SOD) and catalase (CAT) were recovered by OA. By contrast, it was observed that OA decreased the MDA content. Notably, the pretreatment of OA alleviated mitochondria damage by reducing the level of ROS and maintaining MMP. In addition, apoptosis that was caused by high glucose was reduced by OA. Pro‑apoptotic genes (caspase‑3, Fas, Fasl) and anti‑apoptotic gene (Bcl‑2) expression levels were decreased and increased in the OA groups, respectively. Furthermore, the activity of AKT/endothelial nitric oxide synthase (eNOS) signaling was elevated by OA. Taken together, it was suggested that OA could protect against oxidative stress‑induced apoptosis of HUVECs, which was associated with AKT/eNOS signaling pathway.

Endosulfan causes the alterations of DNA damage response through ATM-p53 signaling pathway in human leukemia cells

Exposure to pesticides results in DNA damage and genomic instability. We previously predicted that endosulfan might be associated with leukemia, but the role of endosulfan in leukemia cells has been unexplored. The aim of this study is to elucidate molecular mechanism of endosulfan-induced DNA damage response in human leukemia cells. We performed endosulfan exposure experiments in K562 cells with varying concentrations of endosulfan for 48 h and found that endosulfan lowered cell viability in a dose-dependent manner. We observed the dramatic DNA damage using comet assay and the increase of micronucleus in 75 μM endosulfan-exposed cells. Endosulfan at 75 μM caused the expression alterations of ATM and DNA repair genes such as FANCD2, and BRCA1/2 at different exposure time points (12, 24, 48 h), which was reversed by ATM inhibitor KU-55933. Endosulfan significantly increased the mRNA expression levels of p53 and GADD45A, and decreased PCNA and XRCC2 at 48 h after exposure. Flow cytometric analysis showed that endosulfan at 50 and 75 μM induced cell cycle G1 arrest, a response attributed to down-regulation of CDK6 and up-regulation of p21. We also observed that endosulfan at 50 and 75 μM induced a considerable percentage of cells to undergo apoptosis, as detected by Annexin-V binding assays. Endosulfan resulted in the activation of caspase-3, and elevated the expression levels of PUMA and the ratio of BAX/Bcl-2. These findings suggest that endosulfan caused DNA damage response throughATM-p53 signaling pathway, implicating the potential correlation between endosulfan and leukemia.

The persistent organochlorine pesticide endosulfan modulates multiple epigenetic regulators with oncogenic potential in MCF-7 cells

Environmental cues and chemicals can potentially modulate the phenotypic expression of genome through alterations in the epigenetic mechanisms. Endosulfan is one of the extensively used organochlorine pesticides around the world which is known for its endocrine, neuro- and reproductive toxicity. This study was aimed to investigate the potential of α-endosulfan in modulation of multiple epigenetic enzymes in MCF-7 cells. The cells were treated with DMSO (control) or α-endosulfan (1 and 10μM) and the expression of various epigenetic enzymes was assayed by real-time PCR and immunoblotting, in addition to their activity assays. The results shows α-endosulfan, at 1 and 10μM concentration, significantly promoted viability of MCF-7 cells compared to untreated cells after 24h. The expression of DNA methyltransferases (DNMTs) was upregulated while the global DNA methylation status was initially affected, but later recovered. Total intracellular histone deacetylase (HDAC) activity was found to be significantly increased which was correlated with upregulation of class I HDACs (HDAC 1 and 3) while no significant alteration in the other HDAC classes was observed. The expression and activity of arginine and lysine methylation enzymes, protein arginine methyltransferase 5 (PRMT5) and Enhancer of Zeste homolog 2 (EZH2), respectively, were also found to be modulated by α-endosulfan. We found increased expression of histones H3 and H4, trimethylated H3K27 (product of EZH2), symmetric dimethylation of H4R3 (product of PRMT5) and five different (unidentified) proteins whose arginine residues are symmetrically dimethylated (by increased level of PRMT5) were enhanced in response to 10μM α-endosulfan after 24h exposure window. Moreover, overexpression of basal level of estrogen receptor alpha (ERα), suggests estrogenicity of α-endosulfan. In summary, our results shows modulatory impact of α-endosulfan on multiple cellular epigenetic regulators, known to possess oncogenic potential which might contribute to mechanistic insight of its action in future.

In vitro effects of endosulfan-based insecticides on mammalian sperm

Endosulfan is an organochloride insecticide extensively used in several countries to protect crops from pests. As several studies indicate that endosulfan can affect human and animal development, the aim of this study was to analyse whether sperm parameters and the process of chromatin decondensation could be altered by endosulfan in mice sperm. Spermatozoa from cauda epididymis were obtained from mature male mice and incubated in the presence of two commercial formulations (CFs) of endosulfan (Master® and Zebra Ciagro®) or the active ingredient (AI) alone. A significant decrease in the percentage motility and viability of spermatozoa with respect to controls was found. In vitro decondensation was performed in the presence of glutathione and heparin. Spermatozoa incubated with the AI, endosulfan Master® and endosulfan Zebra Ciagro® showed an increase in chromatin decondensation. In addition, the TUNEL assay showed that DNA fragmentation was significantly higher when sperm were incubated with either one of the CFs when compared to the AI or controls. The ultrastructure analysis of sperm cells showed evident changes in the structure of the plasma and acrosome membranes of sperm incubated with endosulfan AI or the CFs. These results suggest that endosulfan can affect sperm integrity and in vitro chromatin decondensation as well as DNA fragmentation.

A study of DNA damage in buccal cells of consumers of well- and/or tap-water using the comet assay: Assessment of occupational exposure to genotoxicants

Because of concerns that natural aquifers in the region of Todos Santos (Baja California Sur, Mexico) might be contaminated by organochlorine pesticides and heavy metals, a case-control study was conducted among consumers and non-consumers of well- and/or tap-water to determine risks to human health. This study was based on a genotoxic evaluation of buccal cells using the Comet assay technique. Levels of DNA damage in the consumers group were significantly higher than those of the control group. However, occupational exposure to genotoxicants showed to be the critical factor rather than water consumption. Taking into account the professions of well- and/or tap-water consumers, agricultural workers exposed directly (those who fumigated) or indirectly (those not involved in fumigating) to agrochemicals showed greater genetic damage than controls. This difference persisted even when age, and whether the person smoked or consumed alcoholic drinks were considered. These factors were not associated with the level of genetic damage observed. Chemical analyses of organochlorine pesticides and heavy metals were carried out to evaluate the water quality of wells, faucets, and surface water of canals consumed by the population and/or used for irrigation. High concentrations of α and β endosulfan were detected in water of surface canals. Although our inventory of agrochemicals employed in the region showed the use of products considered carcinogenic and/or mutagenic, they were not detected by the analytical techniques used. Heavy metals (arsenic, mercury, and lead) were detected in water of some wells used for irrigation and human consumption. Environ. Mol. Mutagen. 58:619-627, 2017. © 2017 Wiley Periodicals, Inc.

Synergistic cellular effects including mitochondrial destabilization, autophagy and apoptosis following low-level exposure to a mixture of lipophilic persistent organic pollutants

Humans are exposed to multiple exogenous environmental pollutants. Many of these compounds are parts of mixtures that can exacerbate harmful effects of the individual mixture components. 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), is primarily produced via industrial processes including incineration and the manufacture of herbicides. Both endosulfan and TCDD are persistent organic pollutants which elicit cytotoxic effects by inducing reactive oxygen species generation. Sublethal concentrations of mixtures of TCDD and endosulfan increase oxidative stress, as well as mitochondrial homeostasis disruption, which is preceded by a calcium rise and, in fine, induce cell death. TCDD+Endosulfan elicit a complex signaling sequence involving reticulum endoplasmic destalilization which leads to Ca2+ rise, superoxide anion production, ATP drop and late NADP(H) depletion associated with a mitochondrial induced apoptosis concomitant early autophagic processes. The ROS scavenger, N-acetyl-cysteine, blocks both the mixture-induced autophagy and death. Calcium chelators act similarly and mitochondrially targeted anti-oxidants also abrogate these effects. Inhibition of the autophagic fluxes with 3-methyladenine, increases mixture-induced cell death. These findings show that subchronic doses of pollutants may act synergistically. They also reveal that the onset of autophagy might serve as a protective mechanism against ROS-triggered cytotoxic effects of a cocktail of pollutants in Caco-2 cells and increase their tumorigenicity.

Mitochondria and MAPK cascades modulate endosulfan-induced germline apoptosis in Caenorhabditis elegans

Endosulfan as a new member of persistent organic pollutants has been shown to induce apoptosis in various animal models. However, the mechanism underlying endosulfan-induced apoptosis has not been well elucidated thus far. Caenorhabditis elegans N2 wild type and mutant strains were used in the present study to clarify the roles of the mitochondria, the insulin/insulin-like growth factor-1 (IGF-1) signaling pathway, and mitogen-activated protein kinase (MAPK) cascades in α-endosulfan-induced apoptosis. Our results demonstrated a dose- and time-dependent increase of apoptosis in the meiotic zone of the gonad of C. elegans exposed to graded concentrations of endosulfan. The expression levels of sod-3, localized in the mitochondrial matrix, increased greatly after endosulfan exposure. A significant increase in germ cell apoptosis was observed in abnormal methyl viologen sensitivity-1 (mev-1(kn-1)) mutants (with abnormal mitochondrial respiratory chain complex II and higher ROS levels) compared to that in N2 at equal endosulfan concentrations. We found that the insulin/IGF-1 signaling pathway and its downstream Ras/ERK/MAPK did not participate in the endosulfan-induced apoptosis. However, the apoptosis in the loss-of-function strains of JNK and p38 MAPK signaling pathways was completely or mildly suppressed under endosulfan stress. The apoptotic effects of endosulfan were blocked in the mutants of jnk-1/JNK-MAPK, sek-1/MAP2K, and pmk-1/p38-MAPK, suggesting that these downstream genes play an essential role in endosulfan-induced germ cell apoptosis. In contrast, the mkk-4/MAP2K and nsy-1/MAP3K were only partially involved in the apoptosis induction. Our data provide evidence that endosulfan increases germ cell apoptosis, which is regulated by mitochondrial function, JNK and p38 MAPK cascades. These findings contribute to the understanding of the signal transduction pathways involved in endosulfan-induced apoptosis.

Endosulfan inhibits proliferation through the Notch signaling pathway in human umbilical vein endothelial cells

Our previous research showed that endosulfan triggers the extrinsic coagulation pathway by damaging endothelial cells and causes hypercoagulation of blood. To identify the mechanism of endosulfan-impaired endothelial cells, we treated human umbilical vein endothelial cells (HUVECs) with different concentrations of endosulfan, with and without an inhibitor for Notch, N-[N-(3, 5-difluorophenacetyl)-1-alanyl]S-Phenylglycinet-butylester (DAPT, 20 μM), or a reactive oxygen species (ROS) scavenger, N-Acetyl-l-cysteine (NAC, 3 mM), for 24 h. The results showed that endosulfan could inhibit cell viability/proliferation by increasing the release of lactate dehydrogenase (LDH), arresting the cell cycle in both S and G2/M phases, and inducing apoptosis in HUVECs. We also found that endosulfan can damage microfilaments, microtubules, and nuclei; arrest mitosis; remarkably increase the expressions of Dll4, Notch1, Cleaved-Notch1, Jagged1, Notch4, Hes1, and p21; and significantly induce ROS and malondialdehyde production in HUVECs. The presence of DAPT antagonized the above changes of cycle arrest, proliferation inhibition, and expressions of Dll4, Notch1, Cleaved-Notch1, Hes1, and p21 caused by endosulfan; however, NAC could attenuate LDH release; ROS and malondialdehyde production; apoptosis; and the expression levels of Dll4, Notch1, Cleaved-Notch1, Notch4, and Hes1 induced by endosulfan. These results demonstrated that endosulfan inhibited proliferation through the Notch signaling pathway as a result of oxidative stress. In addition, endosulfan can damage the cytoskeleton and block mitosis, which may add another layer of toxic effects on endothelial cells.

Endosulfan inducing apoptosis and necroptosis through activation RIPK signaling pathway in human umbilical vascular endothelial cells

Endosulfan, an organochlorine pesticide, was found in human blood, and its possible cardiovascular toxicity has been suggested. However, the mechanism about endothelial cell injuries induced by endosulfan has remained unknown. In the present study, human umbilical vein endothelial cells (HUVECs) were chosen to explore the toxicity mechanism and were treated with 0, 1, 6, and 12 μg/mL^-1 endosulfan for 24 h, respectively. The results showed that exposure to endosulfan could inhibit the cell viability, increase the release of lactate dehydrogenase (LDH), damage the ultrastructure, and lead to apoptosis and necroptosis in HUVECs. Furthermore, endosulfan upregulated the expressions of receptor-interacting protein kinase 1 (RIPK1), receptor-interacting protein kinase 3 (RIPK3), mixed lineage kinase domain-like (MLKL), caspase 8, and caspase 3, which means the activation of RIPK1 pathways. In addition, endosulfan promoted the increases of ROS, IL-1α, and IL-33 levels while antioxidant N-acetyl-L-cysteine (NAC) effectively attenuated the cytotoxicity from endosulfan. Taken together, these results have demonstrated that endosulfan induces the apoptosis and necroptosis of HUVECs, where the RIPK pathway plays a pro-necroptotic role and NAC plays an anti-necroptotic role. Our results may contribute to understanding cellular mechanisms for endosulfan-induced cardiovascular toxicity.

Inhibition of cell growth and induction of inflammation by endosulfan in HUVEC-C cells

Endosulfan is one of the organochlorine pesticides. It has been associated with a wide range of adverse health effects. However, it is unknown whether endosulfan causes endothelial dysfunction. In the present study, we investigated the effects of endosulfan on human vascular endothelial cells. We exposed human umbilical vein endothelial cells (HUVEC-C) to varying concentrations of endosulfan for 48 h. The results showed that endosulfan lowered cell viability and inhibited cell proliferation in a dose-dependent manner. Flow cytometric analysis showed that endosulfan at 60 μM induced G1 cell cycle arrest, a response attributed to down-regulation of CDK6 and pRb dephosphorylation. We observed that endosulfan at 40 and 60 μM induced a considerable percentage of cells to undergo apoptosis, as detected by Annexin-V binding assays. Endosulfan reduced mitochondrial transmembrane potential, leading to the release of cytochrome c into the cytoplasm; meanwhile, endosulfan also inhibited the mRNA expression level of survivin, which resulted in the activation of caspase-3. These results indicated that the intrinsic mitochondria-mediated pathway was involved in apoptotic process. Exposure to endosulfan increased the secretion and mRNA expression levels of inflammation factors interleukin (IL)-6 and IL-8, suggesting that endosulfan could cause inflammation. Overall, these findings suggested that endosulfan is toxic to HUVEC-C cells, resulting in endothelial dysfunction. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1785-1795, 2016.

Isomers and their metabolites of endosulfan induced cytotoxicity and oxidative damage in SH-SY5Y cells

As an organochlorine insecticide, endosulfan has been widely banned or restricted, but it is still largely used in many developing countries. Previous studies have shown multiple adverse health effects of endosulfan. However, the neurotoxicity of endosulfan has not been fully elucidated. In this study, endosulfan isomers (α-/β-endosulfan) and their major metabolites (endosulfan sulfate, endosulfan diol, and endosulfan lactone) were, respectively, exposed to human neuroblastoma SH-SY5Y cells. Results showed that both α-endosulfan and β-endosulfan caused decrease of cell viability and morphological damages in a dose-dependent manner. Their median effective concentrations (EC50s) were respectively 79.6 μM (α-endosulfan) and 50.37 μM (β-endosulfan) for 72 h exposure. EC50s of α/β-endosulfan mixture were lower than that of the single isomer. However, EC50s of its metabolites were higher than that of technical endosulfan. Endosulfan and its metabolites caused increases of reactive oxygen species and the lipid peroxidation, but decrease of superoxide dismutase in a dose-dependent manner. These results indicate that α-endosulfan exhibits higher neurotoxicity than β-endosulfan. Mixture of endosulfan isomers shows stronger cytotoxicity than the single isomer. After endosulfan is degraded, cytotoxicity of its metabolites decreases gradually. The neurotoxicity of endosulfan and its metabolites is closely related to oxidative damage and antioxidative deficit.

Gene expression profiling to identify the toxicities and potentially relevant disease outcomes due to endosulfan exposure

Endosulfan, one of the most toxic organochlorine pesticides, belongs to a group of persistent organic pollutants. Gene expression profiling offers a promising approach in health hazard identification of chemicals. The aim of this study was to use gene expression profiling to identify the toxicities and potentially relevant human diseases due to endosulfan exposure. We performed DNA microarray analysis to analyze gene expression profiles in human endothelial cells exposed to 20, 40 and 60 μM endosulfan in combination with an endothelial phenotype. Microarray results showed that endosulfan increased the number of altered genes in a dose-dependent manner, and changed the expression of 161 genes across all treatment groups. qRT-PCR closely matched the microarray data for the genes tested. Significantly enriched biological processes for overlapping down-regulated genes include the neurological system process, signal transduction, and homeostatic process in all the dose groups. These down-regulated genes were associated with cytoskeleton organization and DNA repair at low doses, and involved in cell cycle, apoptosis, p53 pathway and carcinogenesis at high doses. Those up-regulated genes were linked to the inflammatory response and transcriptional misregulation in cancer at higher doses. These findings are consistent with our established endothelial phenotypes. Endosulfan may be relevant to human diseases including liver cancer, prostate cancer and leukemia using the NextBio Human Disease Atlas. These results provide molecular evidence supporting the toxicities and carcinogenic potential of endosulfan in humans.

Efficient removal of endosulfan from aqueous solution by UV-C/peroxides: a comparative study

This study explored the efficiency of UV-C-based advanced oxidation processes (AOPs), i.e., UV/S2O8(2-), UV/HSO5(-), and UV/H2O2 for the degradation of endosulfan, an organochlorine insecticide and an emerging water pollutant. A significant removal, 91%, 86%, and 64%, of endosulfan, at an initial concentration of 2.45 μM and UV fluence of 480 mJ/cm(2), was achieved by UV/S2O8(2-), UV/HSO5(-), and UV/H2O2 processes, respectively, at a [peroxide]0/[endosulfan]0 molar ratio of 20. The efficiency of these processes was, however, inhibited in the presence of radical scavengers, such as alcohols (e.g., tertiary butyl alcohol and isopropyl alcohol) and natural organic matter (NOM). The inhibition was also influenced by common inorganic anions in the order of nitrite > bicarbonate > chloride > nitrate ≈ sulfate. The observed pseudo-first-order rate constant decreased while the degradation rate increased with increasing initial concentration of the target contaminant. The degradation mechanism of endosulfan by the AOPs was evaluated revealing the main by-product as endosulfan ether. Results of this study suggest that UV-C-based AOPs are potential methods for the removal of pesticides, such as endosulfan and its by-products, from contaminated water.

The role of plant metabolism in the mutagenic and cytotoxic effects of four organophosphorus insecticides in Salmonella typhimurium and in human cell lines

This study used a cell/microbe co-incubation assay to evaluate the effect of four organophosphorus insecticides (parathion-methyl, azinphos-methyl, omethoate, and methamidophos) metabolized by coriander (Coriandrum sativum). The reverse mutation of Salmonella typhimurium strains TA98 and TA100 was used as an indicator of genetic damage. Treatments with these insecticides inhibited peroxidase activity in plant cells by between 17% (omethoate) and 98% (azinphos-methyl) and decreased plant protein content by between 36% (omethoate) and 99.6% (azinphos-methyl). Azinphos-methyl was the most toxic when applied directly. In the Ames test, treatments applied directly to strain TA100 killed the bacteria; however, the presence of plant metabolism detoxified the system and permitted the growth of bacteria. In strain TA98, plant metabolites of insecticides were mutagenic. This result suggests that the tested pesticides produce mutations through frameshifting. The same pesticides were applied to human skin (HaCaT) and lung (NL-20) cell lines to evaluate their effects on cell viability. Pesticides applied directly were more cytotoxic than the combination of pesticide plus coriander metabolic fraction. Omethoate and methamidophos did not affect the viability of HaCaT cells, but azinphos-methyl and parathion-methyl at 100 and 1000μgmL(-1) significantly decreased viability (p<0.05). The NL-20 cell line was remarkably sensitive to the direct application of insecticides. All of the treatment conditions caused decreases in NL-20 cell viability (e.g., viability decreased to 12.0% after parathion-methyl treatment, to 14.7% after azinphos-methyl treatment, and to 6.9% after omethoate treatment). Similar to the Ames test, all of the insecticides showed decreased toxicity in human cells when they were cultured in the presence of plant metabolism. In conclusion, when the studied organophosphorus insecticides were plant-metabolized, they induced mutations in the bacterial strain TA98. In human cell lines, plant metabolism reduced the cytotoxic properties of the insecticides, and human keratinocytes were more resistant to mortality than bronchial cells.

Flow cytometry detection of lysosomal presence and lysosomal membrane integrity in the three-spined stickleback (Gasterosteus aculeatus L.) immune cells: applications in environmental aquatic immunotoxicology

The neutral red retention assay has been proposed to determine the lysosomal membrane stability in immune cells. Nevertheless, this assay implies many examinations under a microscope at short time intervals and therefore the analysis of few samples. The present study proposes two more rapid, efficient, and sensitive sample analyses using flow cytometry method. Lysosomal presence and lysosomal membrane integrity (LMI) were evaluated on the three-spined stickleback, Gasterosteus aculeatus (L.), a well-described model fish species for aquatic ecotoxicology studies. After development of the two biomarkers, they were validated by ex vivo contamination with endosulfan and copper and by in situ sampling. These immunomarkers were clearly modulated by pollutants and their variations seemed to be correlated with leucocyte mortality. Thus, from a practical point of view, lysosomal presence and LMI may provide novel and efficient means of evaluating immune capacities and indicating the toxic effects of environmental pollution.

Effects of low concentration of endosulfan on proliferation, ERK1/2 pathway, apoptosis and senescence in Nile tilapia (Oreochromis niloticus) splenocytes

Endosulfan is a potent organochlorinated pesticide that is known to induce side effects in aquatic organisms, including Oreochromis niloticus (Nile tilapia). It has been previously shown that endosulfan induces oxidative stress and non-specific activation of splenic macrophages and exacerbated serum interleukin-2 synthesis in Nile tilapia. Endosulfan may promote proliferation of T cells through MAP kinase (MAPK) activated signal transductions. The ERK family of MAPKs includes ERK1 and ERK2. Phosphorylated ERK1/2 (pERK1/2) molecules are involved in many aspects of cellular survival, and are important for apoptosis or oxidative stress-induced senescence. In order to study the mechanisms by which endosulfan affects fish health, the present study was aimed at evaluating the in vitro effects of this insecticide on proliferation, the ERK1/2 pathway, apoptosis and cell senescence in splenocytes from Nile tilapia. Lymphoproliferation was evaluated by colorimetric method using the WST-1 assay. Flow cytometry was used to assess pERK1/2, apoptosis and senescence, using Annexin V-FITC and β-galactosidase respectively. Experimental data showed that exposure to 7 μg mL(-1) of endosulfan per se increased cellular proliferation, but decreased the lymphoproliferative response to mitogenic stimulus with PMA + ionomycin. Splenocytes exposed to endosulfan for 15-180 min showed significantly higher levels of pERK1/2 than the non-exposed control. Endosulfan mediated a decrease in etoposide-induced apoptosis and provoked cell senescence. In conclusion, exposure of immune cells to a low concentration of endosulfan deregulates their function and may facilitate the development of multiple diseases.

Endosulfan upregulates AP-1 binding and ARE-mediated transcription via ERK1/2 and p38 activation in HepG2 cells

Endosulfan is an organochlorine insecticide and has been implicated in neurotoxicity, hepatotoxicity, immunosuppression and teratogenicity. However, the molecular mechanism of endosulfan toxicity is not yet clear. Recent studies demonstrated that oxidative stress induced by endosulfan is involved in its toxicity and accumulating evidence suggests that endosulfan can modulate the activities of stress-responsive signal transduction pathways including extracellular signal regulated kinases (ERK) 1/2. However, none of the previous studies investigated the ability of endosulfan to modulate activating protein-1 (AP-1) binding and antioxidant response element (ARE)-mediated transcription as an underlying mechanism of endosulfan toxicity. In this report, we show that treatment of HepG2 cells with endosulfan significantly increased oxidative stress-responsive transcription via AP-1 activation. In addition, endosulfan-induced transcription was enhanced in cells depleted of glutathione by buthionine sulfoximine (BSO) treatment. Exposure to endosulfan resulted in a significant increase in the activities of MAPKs, ERK1/2 and p38. Endosulfan-induced increases in enzymatic activities of these MAPKs were consistent with MAPK phosphorylation. Endosulfan exposure also caused an increase in c-Jun phosphorylation. These results suggest a model for endosulfan toxicity in which endosulfan increases ERK1/2 and p38 activities and these activated MAPKs then increase c-Jun phosphorylation. Phosphorylated c-Jun, in turn, increases AP-1 activity, which results in activation of ARE-mediated transcription.

Carcinogenic potential of endosulfan and its metabolites based on a quantum chemical model

The aim of the present study was to investigate the carcinogenic potential of endosulfan and its metabolites through electronic parameters that characterize the action of carcinogens, i.e. descriptors such as electron affinity, Δ (HOMO-LUMO), dipole moments, electrostatic attraction, formation heat (H(f)) and permeability of the cell membrane (c Log P). The results reveal that both endosulfan and its metabolites are electrophilic and have carcinogenic potential. Although there are few data on its carcinogenicity in the literature, the findings of the present study indicate that the use of this pesticide represents a risk to the health of the general population, especially rural workers.

Maternal pesticide use and birth weight in the agricultural health study

Studies examining the association between maternal pesticide exposure and low birth weight yield conflicting results. The authors examined the association between maternal pesticide use and birth weight among women in the Agricultural Health Study, a large study of pesticide applicators and their spouses in Iowa and North Carolina. The authors evaluated self-reported pesticide use of 27 individual pesticides in relation to birth weight among 2246 farm women whose most recent singleton birth occurred within 5 years of enrollment (1993-1997). The authors used linear regression models adjusted for site, preterm birth, medical parity, maternal body mass index, height, and smoking. The results showed that mean infant birth weight was 3586 g (+/- 546 g), and 3% of the infants were low birth weight (<2500 g). First-trimester pesticide-related tasks were not associated with birth weight. Ever use of the pesticide carbaryl was associated with decreased birth weight (-82 g, 95% confidence interval [CI] = -132, -31). This study thus provides limited evidence about pesticide use as a modulator of birth weight. Overall, the authors observed no associations between birth weight and pesticide-related activities during early pregnancy; however, the authors have no data on temporal specificity of individual pesticide exposures prior to or during pregnancy and therefore cannot draw conclusions related to these exposure windows. Given the widespread exposure to pesticide products, additional evaluation of maternal pregnancy exposures at specific time windows and subsequent birth outcomes is warranted.

Endosulfan increases seric interleukin-2 like (IL-2L) factor and immunoglobulin M (IgM) of Nile tilapia (Oreochromis niloticus) challenged with Aeromona hydrophila

Endosulfan is a persistent organochlorine insecticide which is extremely toxic to fish. It is known to induce immunological alterations in juvenile Nile tilapia (Oreochromis niloticus) such as increases in phagocytic activity and reactive oxygen species production of spleen macrophages. The purpose of the present study was to demonstrate the effects of acute exposure to a sublethal concentration of endosulfan (7 ppb, 96 h) on parameters of the adaptive humoral immune response of the aforementioned aquatic organism. The effect of endosulfan on the capacity of immune cells to produce interleukin-2 like (IL-2L) factor and immunoglobulin M (IgM) in response to a challenge with (1/2) LD50 of the infectious bacteria Aeromonas hydrophila was evaluated. Experimental results indicate that short, sublethal, endosulfan exposure triggers a succession of events beginning with non-specific activation of macrophages followed by an exacerbated synthesis of the IL-2L factor by activated B cells. This leads to significantly increased secretion of IgM and could in turn facilitate autoantibody production and the development of autoimmune pathologies.

Enantioselective induction of oxidative stress by acetofenate in rat PC12 cells

In a non-chiral environment, the enantiomers of a racemate possessed the identical physico-chemical properties, but in the biological systems they possessed different activities. Considering that the involvement of oxidative damage has been implicated in the toxicities of various pesticides, this study investigated the possibility of enantioselective oxidative stress and cytotoxicity induction by acetofenate (AF) which contains an asymmetrical center on PC12 cells. The results of the cytotoxicity assay indicated that S-(+)-AF presented more toxic effects than R-(-)-AF and (+)-AF. It also demonstrated that S-(+)-AF possessed the strongest effects in induction of reactive oxygen species (ROS) production, decrease in superoxide dismutase (SOD) and catalase (CAT) activities, and increase in malondialdehyde (MDA) level. These results suggested that AF and its enantiomers could induce enantioselective cytotoxicity in PC12 cells mediated by oxidative stress. Therefore, the assessment in environmental safety and new chiral pesticide development should consider enantioselectivity.

Oxidative stress in macrophages from spleen of Nile tilapia (Oreochromis niloticus) exposed to sublethal concentration of endosulfan

Endosulfan is a widely used insecticide with immunosuppressive or immunopotentiating effects which alters the immune response of fish. The effects of the acute exposure to endosulfan on a series of parameters of the innate immune response (IIR) of Nile tilapia (Oreochromis niloticus) were investigated-phagocytosis, production of oxygen reactive species, lipoperoxidation as well as spleen cell viability, relative spleen weight and splenocyte concentration-to fully document the effects of this pesticide on Nile tilapia. Juvenile Nile tilapia were exposed in vivo and for 96h to each one of nine concentrations of endosulfan in order to determine the pesticide's acute toxicity level and calculate the lethal concentration of endosulfan to these organisms (LC(50)=12,795ppb). Functional assays showed that endosulfan, at a level equivalent to (1)/(2)LC(50), altered some parameters of the spleen macrophages of Nile tilapia. Phagocytosis, production of oxygen reactive species, and lipoperoxidation increased significantly in exposed fish. Spleen cell viability and relative spleen weight were lower in exposed organisms compared to non-exposed ones, without reaching statistical significance. Splenocyte concentration was not altered in the present experimental conditions. Thus, in vivo exposure (7ppb) of juvenile organisms stimulated the phagocytic activity up to significant oxidative stress levels as indicated by the increased lipid peroxidation in plasma. It can be concluded that short exposure to low concentration of endosulfan stimulated macrophage activity but that there was no significant reduction in the structural parameters of the IIR.