RESUMO
Although many organochlorine pesticides (OCPs) have been banned or restricted because of their persistence and linkage to neurodegenerative diseases, there is evidence of continued human exposure. In contrast, registered herbicides are reported to have a moderate to low level of toxicity; however, there is little information regarding their toxicity to humans or their combined effects with OCPs. This study aimed to characterize the mechanism of toxicity of banned OCP insecticides (aldrin, dieldrin, heptachlor, and lindane) and registered herbicides (trifluralin, triallate, and clopyralid) detected at a legacy contaminated pesticide manufacturing and packing site using SH-SY5Y cells. Cell viability, LDH release, production of reactive oxygen species (ROS), and caspase 3/7 activity were evaluated following 24 h of exposure to the biocides. In addition, RNASeq was conducted at sublethal concentrations to investigate potential mechanisms involved in cellular toxicity. Our findings suggested that aldrin and heptachlor were the most toxic, while dieldrin, lindane, trifluralin, and triallate exhibited moderate toxicity, and clopyralid was not toxic to SH-SY5Y cells. While aldrin and heptachlor induced their toxicity through damage to the cell membrane, the toxicity of dieldrin was partially attributed to necrosis and apoptosis. Moreover, toxic effects of lindane, trifluralin, and triallate, at least partially, were associated with ROS generation. Gene expression profiles suggested that decreased cell viability induced by most of the tested biocides was related to inhibited cell proliferation. The dysregulation of genes encoding for proteins with anti-apoptotic properties also supported the absence of caspase activation. Identified enriched terms showed that OCP toxicity in SH-SY5Y cells was mediated through pathways associated with the pathogenesis of neurodegenerative diseases. In conclusion, this study provides a basis for elucidating the molecular mechanisms of pesticide-induced neurotoxicity. Moreover, it introduced SH-SY5Y cells as a relevant in vitro model for investigating the neurotoxicity of pesticides in humans.
Assuntos
Neuroblastoma , Doenças Neurodegenerativas , Espécies Reativas de Oxigênio , Humanos , Doenças Neurodegenerativas/induzido quimicamente , Linhagem Celular Tumoral , Espécies Reativas de Oxigênio/metabolismo , Praguicidas/toxicidade , Dieldrin/toxicidade , Inseticidas/toxicidade , Sobrevivência Celular/efeitos dos fármacos , Hidrocarbonetos Clorados/toxicidade , Apoptose/efeitos dos fármacos , Herbicidas/toxicidade , Aldrina/toxicidade , Hexaclorocicloexano/toxicidadeRESUMO
Parkinson's disease (PD) is the fastest-growing neurological disease worldwide, with increases outpacing aging and occurring most rapidly in recently industrialized areas, suggesting a role of environmental factors. Epidemiological, post-mortem, and mechanistic studies suggest that persistent organic pollutants, including the organochlorine pesticide dieldrin, increase PD risk. In mice, developmental dieldrin exposure causes male-specific exacerbation of neuronal susceptibility to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and synucleinopathy. Specifically, in the α-synuclein (α-syn) pre-formed fibril (PFF) model, exposure leads to increased deficits in striatal dopamine (DA) turnover and motor deficits on the challenging beam. Here, we hypothesized that alterations in DA handling contribute to the observed changes and assessed vesicular monoamine transporter 2 (VMAT2) function and DA release in this dieldrin/PFF 2-hit model. Female C57BL/6 mice were exposed to 0.3 mg/kg dieldrin or vehicle every 3 days by feeding, starting at 8 weeks of age and continuing throughout breeding, gestation, and lactation. Male offspring from independent litters underwent unilateral, intrastriatal injections of α-syn PFFs at 12 weeks of age, and vesicular 3H-DA uptake assays and fast-scan cyclic voltammetry were performed 4 months post-PFF injection. Dieldrin-induced an increase in DA release in striatal slices in PFF-injected animals, but no change in VMAT2 activity. These results suggest that developmental dieldrin exposure increases a compensatory response to synucleinopathy-triggered striatal DA loss. These findings are consistent with silent neurotoxicity, where developmental exposure to dieldrin primes the nigrostriatal striatal system to have an exacerbated response to synucleinopathy in the absence of observable changes in typical markers of nigrostriatal dysfunction and degeneration.
Assuntos
Doença de Parkinson , Praguicidas , Sinucleinopatias , Camundongos , Animais , Masculino , Feminino , alfa-Sinucleína/metabolismo , Dopamina , Dieldrin/toxicidade , Camundongos Endogâmicos C57BL , Praguicidas/toxicidade , Proteínas Vesiculares de Transporte de Monoamina , Transmissão Sináptica , Substância Negra/metabolismoRESUMO
The molecular mechanisms of coevolution between plants and insects remain elusive. GABA receptors are targets of many neurotoxic terpenoids, which represent the most diverse array of natural products known. Over deep evolutionary time, as plant terpene synthases diversified in plants, so did plant terpenoid defence repertoires. Here we show that herbivorous insects and their predators evolved convergent amino acid changing substitutions in duplicated copies of the Resistance to dieldrin (Rdl) gene that encodes the GABA receptor, and that the evolution of duplicated Rdl and terpenoid-resistant GABA receptors is associated with the diversification of moths and butterflies. These same substitutions also evolved in pests exposed to synthetic insecticides that target the GABA receptor. We used in vivo genome editing in Drosophila melanogaster to evaluate the fitness effects of each putative resistance mutation and found that pleiotropy both facilitates and constrains the evolution of GABA receptor resistance. The same genetic changes that confer resistance to terpenoids across 300 Myr of insect evolution have re-evolved in response to synthetic analogues over one human lifespan.
Assuntos
Borboletas , Receptores de GABA , Animais , Humanos , Receptores de GABA/genética , Neurotoxinas/farmacologia , Drosophila melanogaster/genética , Resistência a Inseticidas/genética , Dieldrin/toxicidade , Insetos/genética , Terpenos/farmacologiaRESUMO
BACKGROUND: There is evidence that environmental factors contribute to the onset and progression of Parkinson's disease (PD). Pesticides are a class of environmental toxins that are linked to increased risk of developing PD. However, few studies have investigated the association between specific pesticides and PD, especially in China, which was one of the first countries to adopt the use of pesticides. METHODS: In this study, serum levels of 19 pesticides were measured in 90 patients with PD and 90 healthy spouse controls. We also analyzed the interaction between specific pesticides and PD. In addition, the association between pesticides and clinical features of PD was also investigated. Finally, we investigated the underlying mechanism of the association between pesticides and PD. RESULTS: Serum levels of organochlorine pesticides, which included α-hexachlorocyclohexane (HCH), ß-HCH, γ-HCH, δ-HCH, propanil, heptachlor, dieldrin, hexachlorobenzene, p,p'-dichlorodiphenyltrichloroethane and o,p'-dichloro-diphenyl-trichloroethane were higher in PD patients than controls. Moreover, α-HCH and propanil levels were associated with PD. Serum levels of dieldrin were associated with Hamilton Depression Scale and Montreal Cognitive Assessment scores in PD patients. In SH-SY5Y cells, α-HCH and propanil increased level of reactive oxygen species and decreased mitochondrial membrane potential. Furthermore, propanil, but not α-HCH, induced the aggregation of α-synuclein. CONCLUSIONS: This study revealed that elevated serum levels of α-HCH and propanil were associated with PD. Serum levels of dieldrin were associated with depression and cognitive function in PD patients. Moreover, propanil, but not α-HCH, induced the aggregation of α-synuclein. Further research is needed to fully elucidate the effects of pesticides on PD.
Assuntos
Hidrocarbonetos Clorados/sangue , Doença de Parkinson/sangue , Praguicidas/sangue , Idoso , Western Blotting , Estudos de Casos e Controles , Linhagem Celular Tumoral , Cognição/efeitos dos fármacos , Transtornos Cognitivos/sangue , Transtornos Cognitivos/induzido quimicamente , Depressão/sangue , Depressão/induzido quimicamente , Dieldrin/sangue , Dieldrin/toxicidade , Feminino , Hexaclorocicloexano/sangue , Hexaclorocicloexano/toxicidade , Humanos , Hidrocarbonetos Clorados/toxicidade , Masculino , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Pessoa de Meia-Idade , Doença de Parkinson/etiologia , Praguicidas/toxicidade , Propanil/sangue , Propanil/toxicidade , Espécies Reativas de Oxigênio/metabolismo , Fatores de RiscoRESUMO
Organochlorine pesticides are highly persistent environmental pollutants, generally shown to act through estrogen receptor alpha and alter estrogen biosynthesis. However, the molecular mechanism of regulation of estrogen biosynthesis by these pesticides is not clear. Estrogen is main female fertility hormone regulated by rate-limiting enzyme aromatase. It is encoded by the CYP19A1 gene, which is expressed using specific promoters. In the present study, the attempt has been made to elucidate the effect of dieldrin on the promoter-specific CYP19A1 gene expression and estrogen hormone production in buffalo granulosa cells. The buffalo granulosa cells were cultured and treated with dieldrin in a dose (100,150 and 200 ng/mL) and time (6, 12, and 24 h) dependent manner, followed by analysis of CYP19A1, promoter-specific CYP19A1 transcript expression, and estrogen production. Results showed that dieldrin significantly increased the expression of the CYP19A1 gene after 6 and 12 h while its expression was decreased after 24 h. To understand the upregulation of CYP19A1 gene, promoters' specific CYP19A1 transcript analysis was done. The finding showed that dieldrin significantly increased the proximal promoter specific CYP19A1 transcript while there was no effect on distal promoter specific CYP19A1 transcripts. This specific-promoter activity was quantified by chromatin immunoprecipitation assay (ChIP). Results confirmed the involvement of the proximal promoter in the overexpression of CYP19A1 gene. Furthermore, a significant increase in estradiol-17ß level was also observed. Overall, the present study demonstrated the stimulatory effect of dieldrin on the CYP19A1 gene and will help to understand the toxicological role of dieldrin on the reproductive system.
Assuntos
Família 19 do Citocromo P450/genética , Dieldrin/toxicidade , Estrogênios/metabolismo , Células da Granulosa/efeitos dos fármacos , Regiões Promotoras Genéticas/fisiologia , Animais , Búfalos , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Imunoprecipitação da Cromatina , Feminino , Células da Granulosa/metabolismo , Reação em Cadeia da Polimerase , Progesterona/análise , Regulação para CimaRESUMO
Organochlorine pesticides (OCPs) are persistent pollutants linked to diverse adverse health outcomes. Environmental exposure to OCPs has been suggested to negatively impact the immune system but their effects on cellular antiviral responses remain unknown. Transcriptomic analysis of N27 rat dopaminergic neuronal cells unexpectedly detected high level expression of genes in the interferon (IFN)-related antiviral response pathways including the IFN-induced protein with tetratricopeptide repeats 1 and 2 (Ifit1/2) and the MX Dynamin Like GTPases Mx1 and Mx2. Interestingly, treatment of N27 cells with dieldrin markedly downregulated the expression of many of these genes. Dieldrin exterted a similar effect in inhibiting IFIT2 and MX1 gene expression in human SH-SY5Y neuronal cells induced by an RNA viral mimic, polyinosinic: polycytidylic acid (poly I:C) and IFIT2/3 gene expression in human pulmonary epithelial cells exposed to human influenza H1N1 virus. Mechanistically, dieldrin induced a rapid rise in levels of intracellular reactive oxygen species (iROS) and a decrease in intracellular glutathione (GSH) levels in SH-SY5Y cells. Treatment with N-acetylcysteine, an antioxidant and GSH biosynthesis precursor, effectively blocked both dieldrin-induced increases in iROS and its inhibition of poly I:C-induced upregulation of IFIT and MX gene expression, suggesting a role for intracellular oxidative status in dieldrin's modulation of antiviral gene expression. This study demonstrates that dieldrin modulates key genes of the cellular innate immune responses that are normally involved in the host's cellular defense against viral infections. Our findings have potential relevance to understanding the organismal effects of environmentally persistent organochlorine contaminants on the mammalian cellular immune system.
Assuntos
Vírus da Influenza A Subtipo H1N1 , Praguicidas , Animais , Antivirais , Dieldrin/toxicidade , Neurônios Dopaminérgicos , Expressão Gênica , Humanos , Interferons , Praguicidas/toxicidade , RatosRESUMO
Dieldrin and DDE are environmental metabolites of the organochlorine pesticides aldrin and DDT, respectively. During pregnancy, these chemicals can quickly infiltrate through the placental barrier, accumulate in amniotic fluid and fetus, and act as endocrine disruptors (EDs). The aim of this study was to investigate the effect of DDE and dieldrin and their parental substances at concentrations of 1 and 10 ng/ml on secretion of PGE2 and PGF2α from bovine endometrial explants (120-150 and 151-180 days of pregnancy) after 24 hr of incubation with EDs. The mRNA expression of COX2, PGES and PGFS and the concentrations of PGE2 and PGF2α were measured. EDs did not affect (p>0.05) COX2 gene expression, but DDT and DDE decreased (p⟨0.05) PGES expression and PGE2 secretion in the explants from 120-150 days of pregnancy. Depending on the dose, DDT and DDE increased (p⟨0.05) PGFS expression and PGF2α secretion from the explants from 120-150 days and decreased PGF2α secretion (p⟨0.05) from the explants from 151-180 days of pregnancy. Aldrin and dieldrin decreased (p⟨0.05) PGFS expression and PGF2α secretion from all explants. In summary, EDs disrupt the secretion of PGE2 and PGF2α by influencing the gene expression of PGES and PGFS.
Assuntos
Bovinos/fisiologia , Dinoprosta/metabolismo , Dinoprostona/metabolismo , Endométrio/efeitos dos fármacos , Inseticidas/farmacologia , Aldrina/farmacologia , Aldrina/toxicidade , Animais , Ciclo-Oxigenase 2/genética , Ciclo-Oxigenase 2/metabolismo , DDT/farmacologia , DDT/toxicidade , Diclorodifenil Dicloroetileno/farmacologia , Diclorodifenil Dicloroetileno/toxicidade , Dieldrin/farmacologia , Dieldrin/toxicidade , Dinoprosta/genética , Dinoprostona/genética , Feminino , Regulação da Expressão Gênica/efeitos dos fármacos , Inseticidas/metabolismo , Inseticidas/toxicidade , Gravidez , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Técnicas de Cultura de Tecidos/veterináriaRESUMO
The toxicity of copper, cadmium, and dieldrin in adult Gammarus locusta (a marine amphipod) is currently unclear. Thus, G. locusta from the North Lake of Tunis were subjected to acute toxicity tests to assess LC50s at 48-96 h and to biomarker response tests through the assessment of catalase and acetylcholinesterase activities and malondialdehyde levels. The present study demonstrated the abilities of a chlorinated hydrocarbon pesticide (dieldrin) induce to oxidative stress and neurotoxicity. The comparison of metal toxicity showed that G. locusta was more sensitive to cadmium than copper. The three stressors caused significant inductions of all three biomarkers in a concentration-dependent manner. Catalase induction was dependent on exposure duration for all pollutants, while only copper led to increased malondialdehyde with longer exposure times. Catalase induction and malondialdehyde increase appeared to be sex dependent for all three pollutants. The neurotoxic effects of the pollutants were concentration dependent according to inhibition of acetylcholinesterase activity. In conclusion, catalase, malondialdehyde, and acetylcholinesterase are efficient biomarkers of copper, cadmium, and dieldrin in G. locusta.
Assuntos
Anfípodes , Inseticidas , Poluentes Químicos da Água , Animais , Biomarcadores , Cádmio/toxicidade , Cobre/toxicidade , Dieldrin/toxicidade , Inseticidas/toxicidade , Poluentes Químicos da Água/toxicidadeRESUMO
Dietary exposure to chemicals alters the diversity of microbiome communities and can lead to pathophysiological changes in the gastrointestinal system. The organochlorine pesticide dieldrin is a persistent environmental contaminant that bioaccumulates in fatty tissue of aquatic organisms. The objectives of this study were to determine whether environmentally-relevant doses of dieldrin altered gastrointestinal morphology and the microbiome of zebrafish. Adult zebrafish at â¼4 months of age were fed a measured amount of feed containing either a solvent control or one of two doses of dieldrin (measured at 16, and 163.5 ng/g dry weight) for 4 months. Dieldrin body burden levels in zebrafish after four-month exposure were 0 (control), 11.47 ± 1.13 ng/g (low dose) and 18.32 ± 1.32 ng/g (high dose) wet weight [mean ± std]. Extensive histopathology at the whole organism level revealed that dieldrin exposure did not induce notable tissue pathology, including the gastrointestinal tract. A repeated measure mixed model analysis revealed that, while fish gained weight over time, there were no dieldrin-specific effects on body weight. Fecal content was collected from the gastrointestinal tract of males and 16S rRNA gene sequencing conducted. Dieldrin at a measured feed dose of 16 ng/g reduced the abundance of Firmicutes, a phylum involved in energy resorption. At the level of class, there was a decrease in abundance of Clostridia and Betaproteobacteria, and an increase in Verrucomicrobiae species. We used a computational approach called predicted relative metabolomic turnover (PRMT) to predict how a shift in microbial community composition affects exchange of metabolites. Dieldrin was predicted to affect metabolic turnover of uroporphyrinogen I and coproporphyrinogen I [enzyme]-cysteine, hydrogen selenide, selenite, and methyl-selenic acid in the fish gastrointestinal system. These pathways are related to bacterial heme biosynthesis and selenium metabolism. Our study demonstrates that dietary exposures to dieldrin can alter microbiota composition over 4 months, however the long-term consequences of such impacts are not well understood.
Assuntos
Microbiota , Selênio , Animais , Dieldrin/toxicidade , Trato Gastrointestinal , Heme , Masculino , RNA Ribossômico 16S , Peixe-ZebraRESUMO
Chlorooganic xenobiotics (XBs) such as DDT, DDE, aldrin and dieldrin interfere with release of hormones from chorionic villi that are necessary for sustaining the normal course pregnancy: prostaglandins (PGs), oxytocin (OT), progesterone (P4) and estradiol (E2). Approximately 20 %-40 % of these hormones originate from the smooth chorion. The aim of current studies was to investigate effects of these XBs on synthesis and release of PGE2, PGF2α, OT, P4 and E2 from explants of smooth chorion of cattle, obtained during the120-150 and 151-180 day gestational period. Explants were incubated with DDT, DDE, aldrin or dieldrin at concentrations of 1 and 10 ng/mL for 24 h, and concentrations of PGE2, PGF2α, OT, P4 and E2 in post incubation medium and the relative abundances of COX-2, PTGES, AKR1B1, NP-I/OT, PAM, HSD3B, and CYP19A1 mRNA transcripts in tissue explants were determined. The XBs did not have effects on cell viability in explants (P > 0.05), however, there were effects on prostaglandins, OT and P4 secretion and relative abundance of mRNA transcript for genes encoding the main enzymes involved in synthesis of these hormones (P < 0.05). The XBs that were evaluated did not have effects on E2 synthesis and secretion (P > 0.05). In summary, XBs evaluated in the present study had effects on the pattern of prostaglandin secretion, and can increase OT and P4 release from smooth chorion explants. Because XBs inhibit hormonal action throughout the chorion, there is an increase in risk of abortions or premature births in animals.
Assuntos
Córion/efeitos dos fármacos , Hormônios Esteroides Gonadais/metabolismo , Inseticidas/toxicidade , Ocitocina/metabolismo , Prostaglandinas/metabolismo , Aldrina/toxicidade , Animais , Bovinos , Córion/citologia , DDT/toxicidade , Diclorodifenil Dicloroetileno/toxicidade , Dieldrin/toxicidade , Feminino , Regulação da Expressão Gênica/efeitos dos fármacos , Hormônios Esteroides Gonadais/genética , Ocitocina/genética , Gravidez , Prostaglandinas/genética , Técnicas de Cultura de TecidosRESUMO
The resistance to dieldrin gene (Rdl) encodes a subunit of the insect γ-amino butyric acid (GABA) receptor, and the encoded Rdl subunit is a major target site for cyclodiene and phenylpyrazole insecticides. Since the substitution of a single amino acid (Ala to Ser/Gly at position 302) of the Drosophila melanogaster Rdl gene was first identified to confer high level resistance to dieldrin, mutations at the equivalent positions have been reported to confer resistance to dieldrin and/or fipronil in a wide range of different insects. In the cotton bollworm Helicoverpa armigera, there are two Rdl homologs (HaRdl-1 and HaRdl-2) in close proximity on the Z chromosome, which as wild-type sequences, encode alanine and serine respectively at amino acid position 302. In the present study, we used the CRISPR/Cas9 gene editing approach to knock out HaRdl-1 and HaRdl-2 and establish two homozygous knockout strains (ΔRdl-1 and ΔRdl-2). The ΔRdl-1 strain showed low levels of resistance (8.0- to 9.3-fold) to three cyclodiene insecticides (endosulfan, aldrin and dieldrin) compared with the background SCD strain. In contrast, toxicity of the three cyclodiene insecticides to the ΔRdl-2 strain increased significantly (3.6- to 6.3-fold) when compared with the SCD strain. Genetic analysis indicated the obtained resistance to endosulfan and dieldrin in the ΔRdl-1 strain was sex-linked, which is consistent with the fact that HaRdl-1 locus is located on the Z chromosome. The above results demonstrate that both HaRdl-1 and HaRdl-2 are important determinants for the susceptibility of H. armigera SCD strain to the three cyclodiene insecticides, but have opposite effects. It was also found that HaRdl-1 and HaRdl-2 are involved, to some extent, in mediating sensitivity of H. armigera to avermectin and fipronil respectively. We speculate that the HaRdl-1 and HaRdl-2 subunits have different pharmacological properties, which contribute to the differential sensitivities of H. armigera to the tested cyclodienes and other insecticides.
Assuntos
Proteínas de Drosophila/genética , Inseticidas/farmacologia , Inseticidas/toxicidade , Mariposas/genética , Animais , Dieldrin/toxicidade , Drosophila melanogaster/genética , Resistência a Inseticidas/efeitos dos fármacos , Resistência a Inseticidas/genética , Receptores de GABA/genética , Receptores de GABA-A/genética , Genética ReversaRESUMO
Dieldrin has been shown to induce liver tumors selectively in mice. Although the exact mechanism is not fully understood, previous studies from our laboratory and others have shown that dieldrin induced liver tumors in mice through a non-genotoxic mechanism acting on tumor promotion stage. Two studies were performed to examine the role of nuclear receptor activation as a possible mode of action (MOA) for dieldrin-induced mouse liver tumors. In the initial study, male C57BL/6 mice (6- to 8-week old) were treated with dieldrin in diet (10 ppm) for 7, 14, and 28 days. Phenobarbital (PB), beta-naphthoflavone (BNF) and Di (2-ethylhexyl) phthalate (DEHP) were included as positive controls in this study for evaluating the involvement of CAR (constitutive androstane receptor), AhR (aryl hydrocarbon receptor) or PPARα (peroxisome proliferator activated receptor alpha) in the MOA of dieldrin hepatocarcinogenesis. A significant increase in hepatocyte DNA synthesis (BrdU incorporation) was seen in treated mice compared with the untreated controls. Analysis of the expression of the nuclear receptor responsive genes revealed that dieldrin induced a significant increase in the expression of genes specific to CAR activation (Cyp2b10, up to 400- to 2700-fold) and PXR activation (Cyp3a11, up to 5- to 11-fold) over untreated controls. The AhR target genes Cyp1a1 and Cyp1a2 were also slightly induced (2.0- to 3.7-fold and 1.7- to 2.8-fold, respectively). PPARα activation was not seen in the liver following dieldrin treatment. In addition, consistent with previous studies in our lab, treatment with dieldrin produced significant elevation in the hepatic oxidative stress. In a subsequent study using CAR, PXR, and CAR/PXR knockout mice, we confirmed that the dieldrin-induced liver effects in mouse were only mediated by the activation of CAR receptor. Based on these findings, we propose that dieldrin induced liver tumors in mice through a nuclear receptor CAR-mediated mode of action. The previously observed oxidative stress/damage may be an associated or modifying factor in the process of dieldrin-induced liver tumor formation subsequent to the CAR activation.
Assuntos
Transformação Celular Neoplásica/induzido quimicamente , Dieldrin/toxicidade , Inseticidas/toxicidade , Neoplasias Hepáticas/induzido quimicamente , Fígado/efeitos dos fármacos , Receptores Citoplasmáticos e Nucleares/agonistas , Animais , Hidrocarboneto de Aril Hidroxilases/biossíntese , Hidrocarboneto de Aril Hidroxilases/genética , Transformação Celular Neoplásica/genética , Transformação Celular Neoplásica/metabolismo , Receptor Constitutivo de Androstano , Família 2 do Citocromo P450/biossíntese , Família 2 do Citocromo P450/genética , Replicação do DNA/efeitos dos fármacos , Indução Enzimática , Fígado/metabolismo , Fígado/patologia , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Estresse Oxidativo/efeitos dos fármacos , PPAR alfa/genética , PPAR alfa/metabolismo , Receptor de Pregnano X/genética , Receptor de Pregnano X/metabolismo , Receptores Citoplasmáticos e Nucleares/metabolismo , Transdução de Sinais , Esteroide Hidroxilases/biossíntese , Esteroide Hidroxilases/genéticaRESUMO
Organochlorine pesticides, once widely used, are extremely persistent and bio-accumulative in the environment. Epidemiological studies have implicated that environmental exposure to organochlorine pesticides including dieldrin is a risk factor for the development of Parkinson's disease. However, the pertinent mechanisms of action remain poorly understood. In this study, we carried out a genome-wide (Brunello library, 19 114 genes, 76 411 sgRNAs) CRISPR/Cas9 screen in human dopaminergic SH-SY5Y neuronal cells exposed to a chronic treatment (30 days) with dieldrin to identify cellular pathways that are functionally related to the chronic cellular toxicity. Our results indicate that dieldrin toxicity was enhanced by gene disruption of specific components of the ubiquitin proteasome system as well as, surprisingly, the protein degradation pathways previously implicated in inherited forms of Parkinson's disease, centered on Parkin. In addition, disruption of regulatory components of the mTOR pathway which integrates cellular responses to both intra- and extracellular signals and is a central regulator for cell metabolism, growth, proliferation, and survival, led to increased sensitivity to dieldrin-induced cellular toxicity. This study is one of the first to apply a genome-wide CRISPR/Cas9-based functional gene disruption screening approach in an adherent neuronal cell line to globally decipher cellular mechanisms that contribute to environmental toxicant-induced neurotoxicity and provides novel insight into the dopaminergic neurotoxicity associated with chronic exposure to dieldrin.
Assuntos
Sistemas CRISPR-Cas , Dieldrin , Neurônios Dopaminérgicos/efeitos dos fármacos , Praguicidas , Linhagem Celular , Dieldrin/toxicidade , Humanos , Praguicidas/toxicidadeRESUMO
Human and animal studies have shown that exposure to the organochlorine pesticide dieldrin is associated with increased risk of Parkinson's disease (PD). Previous work showed that developmental dieldrin exposure increased neuronal susceptibility to MPTP toxicity in male C57BL/6 mice, possibly via changes in dopamine (DA) packaging and turnover. However, the relevance of the MPTP model to PD pathophysiology has been questioned. We therefore studied dieldrin-induced neurotoxicity in the α-synuclein (α-syn)-preformed fibril (PFF) model, which better reflects the α-syn pathology and toxicity observed in PD pathogenesis. Specifically, we used a "two-hit" model to determine whether developmental dieldrin exposure increases susceptibility to α-syn PFF-induced synucleinopathy. Dams were fed either dieldrin (0.3 mg/kg, every 3-4 days) or vehicle corn oil starting 1 month prior to breeding and continuing through weaning of pups at postnatal day 22. At 12 weeks of age, male and female offspring received intrastriatal α-syn PFF or control saline injections. Consistent with the male-specific increased susceptibility to MPTP, our results demonstrate that developmental dieldrin exposure exacerbates PFF-induced toxicity in male mice only. Specifically, in male offspring, dieldrin exacerbated PFF-induced motor deficits on the challenging beam and increased DA turnover in the striatum 6 months after PFF injection. However, male offspring showed neither exacerbation of phosphorylated α-syn aggregation (pSyn) in the substantia nigra (SN) at 1 or 2 months post-PFF injection, nor exacerbation of PFF-induced TH and NeuN loss in the SN 6 months post-PFF injection. Collectively, these data indicate that developmental dieldrin exposure produces a male-specific exacerbation of synucleinopathy-induced behavioral and biochemical deficits. This sex-specific result is consistent with both previous work in the MPTP model, our previously reported sex-specific effects of this exposure paradigm on the male and female epigenome, and the higher prevalence and more severe course of PD in males. The novel two-hit environmental toxicant/PFF exposure paradigm established in this project can be used to explore the mechanisms by which other PD-related exposures alter neuronal vulnerability to synucleinopathy in sporadic PD.
Assuntos
Dieldrin/toxicidade , Atividade Motora/efeitos dos fármacos , Transtornos Parkinsonianos/induzido quimicamente , Transtornos Parkinsonianos/patologia , Praguicidas/toxicidade , Agregação Patológica de Proteínas , alfa-Sinucleína/toxicidade , Animais , Dopamina/metabolismo , Feminino , Masculino , Camundongos Endogâmicos C57BL , Agregação Patológica de Proteínas/induzido quimicamente , Agregação Patológica de Proteínas/metabolismo , Fatores Sexuais , Substância Negra/metabolismo , Substância Negra/patologia , alfa-Sinucleína/administração & dosagemRESUMO
The organochlorine dieldrin (DLD) bioaccumulates in lipid-rich tissues and is associated with immunosuppression, altered metabolism, and cancer. The objective of this study was to determine the effect of DLD on the hepatic proteome in zebrafish following dietary treatment as the liver is central to metabolism. Females were fed a control dose or one of three doses of DLD-contaminated food pellets over 21â¯days. Both label-free and iTRAQ proteomics were conducted as two complementary methods to expand coverage of the proteome. Label-free proteomics quantified 1563 proteins: 6 proteins showed a linear dose-response with DLD. iTRAQ quantified >3500 proteins; 5 proteins were decreased and 34 proteins were increased in abundance within the liver with all three doses. Overall, DLD reduced the abundance of proteins associated with glucose and cholesterol metabolism, lipid oxidation, liver function, and immune-related processes. Few proteins were identified by both methods as being altered (~1%), suggesting that each method detected different subsets of proteins. Protein responses in the liver were largely dependent on dose, however proteins related to liver and organ function, centrosome separation, glucose/energy metabolism, and immune-related pathways were confirmed by each independent technique and were suppressed with DLD exposure. This study identifies proteomic responses that are associated with organochlorine-induced hepatotoxicity. BIOLOGICAL SIGNIFICANCE: Environmental contaminants cause hepatotoxicity because the liver is the major organ for detoxification. The legacy pesticide dieldrin significantly bioaccumulates in tissues, and can affect molecular processes that can lead to liver pathology. LC MS/MS proteomics identified protein networks related to tumors, energy homeostasis, and chromosomal separation as those affected by dietary exposure to dieldrin. We applied two orthogonal mass spectrometry-based methods to more completely survey the liver proteome, strengthening data interpretation. These data improve understanding as to the effects of organochlorine pesticide toxicity in the liver and the study identifies proteome networks that can contribute to adverse outcome pathways for pesticide exposure.
Assuntos
Dieldrin/toxicidade , Fígado/metabolismo , Praguicidas/toxicidade , Proteômica , Proteínas de Peixe-Zebra/metabolismo , Peixe-Zebra/metabolismo , Animais , Exposição DietéticaRESUMO
Human and animal studies have shown that exposure to the organochlorine pesticide dieldrin is associated with increased risk of Parkinson's disease (PD). Despite previous work showing a link between developmental dieldrin exposure and increased neuronal susceptibility to MPTP toxicity in male C57BL/6 mice, the mechanism mediating this effect has not been identified. Here, we tested the hypothesis that developmental exposure to dieldrin increases neuronal susceptibility via genome-wide changes in DNA methylation. Starting at 8 weeks of age and prior to mating, female C57BL/6 mice were exposed to 0.3 mg/kg dieldrin by feeding (every 3 days) throughout breeding, gestation, and lactation. At 12 weeks of age, pups were sacrificed and ventral mesencephalon, containing primarily substantia nigra, was microdissected. DNA was isolated and dieldrin-related changes in DNA methylation were assessed via reduced representation bisulfite sequencing. We identified significant, sex-specific differentially methylated CpGs (DMCs) and regions (DMRs) by developmental dieldrin exposure (false discovery rate < 0.05), including DMCs at the Nr4a2 and Lmx1b genes, which are involved in dopaminergic neuron development and maintenance. Developmental dieldrin exposure had distinct effects on the male and female epigenome. Together, our data suggest that developmental dieldrin exposure establishes sex-specific poised epigenetic states early in life. These poised epigenomes may mediate sensitivity to subsequent toxic stimuli and contribute to the development of late-life neurodegenerative disease, including PD.
Assuntos
Metilação de DNA/efeitos dos fármacos , Dieldrin/toxicidade , Neurônios Dopaminérgicos/efeitos dos fármacos , Feto/efeitos dos fármacos , Mesencéfalo/efeitos dos fármacos , Doença de Parkinson/etiologia , Animais , Neurônios Dopaminérgicos/fisiologia , Feminino , Proteína Adaptadora GRB10/genética , Masculino , Mesencéfalo/metabolismo , Camundongos Endogâmicos C57BL , Caracteres SexuaisRESUMO
The correlation between endocrine active contaminants in the environment and alterations in reproductive development of Sarotherodon melanotheron from Lagos lagoon has been investigated. Sediment and a total of 155 fish (74 males and 81 females) were collected between November 2014-March 2015 from selected contaminated sites (Ikorodu, Oworonshoki, Makoko and Idumota) and a putative control site (Igbore) along the lagoon. Sediment contaminant analysis revealed, significantly higher concentration of lindane, dieldrin, 4-iso-nonylphenol, 4-t-octylphenol and monobutyltin cation at the contaminated sites. Examination of gross morphological and histological changes of fish gonads showed a 27.4% prevalence of intersex in the sampled fish, of which 78% were males (testes-ova) and 22% were females (ovo-testis). Quantitative PCR (qPCR) of liver transcripts revealed the presence of vitellogenin (vtg) levels in male fish from contaminated sites. Zona radiata proteins (zrp) mRNA levels were significantly higher in females, compared to male fish. In general, significantly lower vtg and zrp transcripts levels were recorded at Igbore (control site), compared with contaminated sites. Principal component analysis (PCA) showed site and sex relationship in biological responses and contaminants, including trace metals, demonstrating that measured endocrine responses in fish were associated with contaminant burden in sediment. In addition, positive relationships were observed in male fish from Idumota, Oworonshoki and Ikorodu with vtg and dieldrin/4-iso-nonyphenol, with higher levels in male fish, compared to females. Further, contaminants from the Makoko, Oworonshoki and Ikorodu sites were positively associated with higher GSI and zrp in females. More importantly, the severity of intersex and changes in vtg transcripts imply a progressive feminization of male fish with concomitant alteration in the reproductive health of fish inhabiting the Lagos lagoon.
Assuntos
Ciclídeos/embriologia , Ciclídeos/fisiologia , Transtornos do Desenvolvimento Sexual/induzido quimicamente , Disruptores Endócrinos/análise , Disruptores Endócrinos/toxicidade , Sedimentos Geológicos/química , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade , Animais , Dieldrin/análise , Dieldrin/toxicidade , Feminino , Hexaclorocicloexano/análise , Hexaclorocicloexano/toxicidade , Fígado/metabolismo , Masculino , Nigéria , Ovário/efeitos dos fármacos , Ovário/embriologia , Fenóis/análise , Fenóis/toxicidade , Testículo/efeitos dos fármacos , Testículo/embriologia , Vitelogeninas/metabolismoRESUMO
Environmental exposure to the highly persistent chlorinated pesticides including dieldrin and lindane is postulated to be a risk factor to the development of Parkinson's disease, a devastating movement disorder. We have previously reported that the combined treatment with dieldrin and lindane induces a cooperative toxicity in the rat N27 dopaminergic neuronal cells through increased oxidative stress and mitochondrial dysfunction. In this study, we investigated the involvement of NADPH oxidase (NOX) proteins in the combined treatment with dieldrin and lindane-induced dopaminergic neurotoxicity. Immunoblot analysis demonstrated the presence of NADPH Oxidase 1 (Nox1) isoform and p67phox in N27 neurons. Furthermore, treatment with dieldrin and lindane upregulated the cellular expression of Nox1 but not p67phox protein. Functionally, dieldrin and lindane-induced ROS production was attenuated, in a dose-dependent manner, by Nox inhibitors diphenylene iodonium and apocynin. Subcellular localization analysis of Nox1 and p67phox proteins indicated colocalization of both subunits with mitochondria in untreated cells. Treatment with dieldrin and lindane further increased mitochondrial colocalization of Nox1 protein, suggesting a potentially prominent role for mitochondrial Nox1 protein in dieldrin and lindane-induced ROS generation in dopaminergic neurons and its contribution to the combined organochlorinated pesticide-induced neurotoxicity.
Assuntos
Dieldrin/toxicidade , Neurônios Dopaminérgicos/efeitos dos fármacos , Poluentes Ambientais/toxicidade , Hexaclorocicloexano/toxicidade , NADPH Oxidase 1/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Animais , Técnicas de Cultura de Células , Linhagem Celular , Neurônios Dopaminérgicos/metabolismo , Sinergismo Farmacológico , Ratos , Frações Subcelulares/efeitos dos fármacos , Frações Subcelulares/enzimologiaRESUMO
One level at which persistent organic pollutants (POPs) and polycyclic aromatic hydrocarbons PAHs) can exert damage is by causing DNA strand-breaks or nucleotide base modifications, which, if unrepaired, can lead to embryonic mutations, abnormal development and cancer. In marine ecosystems, genotoxicity is expected to be particularly strong in long-lived apex predators due to pollutant bioaccumulation. We conducted 32 P-postlabeling analyses optimized for the detection and quantification of aromatic/hydrophobic DNA adducts in the livers of 40 sexually-mature North Atlantic harbour porpoises (Phocoena phocoena) stranded along the English and Welsh coastlines. We examined hepatic tissue to search for inflammatory and preneoplastic lesions and examine their association with adduct levels. Adducts were found in all porpoises (mean: 17.56 ± 11.95 per 108 nucleotides), and were higher than levels reported for marine vertebrates from polluted sites. The pollutants causing the induced DNA adducts could not be further characterized. Hepatic DNA damage did not correlate with levels of blubber POP concentrations (including total polychlorinated biphenyl [PCBs], dichlorodiphenyltrichloroethane [DDT] and dieldrin); PAH concentrations were not available for the present study. However, DNA damage predicted occurrence of inflammatory and preneoplastic lesions. Further, our data showed a reduction in hepatic DNA adduct levels with age in the 40 animals examined while POP concentrations, particularly PCBs, increased with age. Using a different dataset of 145 mature male harbour porpoises confirmed that higher contaminant levels (total PCBs, DDT and dieldrin) are found in older animals. The reduction in hepatic DNA adduct levels in older animals was in accordance with other studies which show that suppression of hepatic CYP1A enzyme activity at high PCB concentrations might impact on CYP1A-mediated DNA adduct formation of PAHs which are ubiquitous environmental pollutants and readily metabolized by CYP1A to species binding to DNA. In summary, our study shows that pollutant-induced DNA damage is prevalent in harbour porpoises from UK waters and may lead to detectable sub-lethal hepatic damage. Environ. Mol. Mutagen. 59:613-624, 2018. © 2018 The Authors Environmental and Molecular Mutagenesis published by Wiley Periodicals, Inc. on behalf of Environmental Mutagen Society.
Assuntos
Dano ao DNA/efeitos dos fármacos , Fígado/efeitos dos fármacos , Mutagênicos/toxicidade , Phocoena/genética , Bifenilos Policlorados/toxicidade , Hidrocarbonetos Policíclicos Aromáticos/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Carcinógenos Ambientais/toxicidade , DDT/toxicidade , Dieldrin/toxicidade , Inglaterra , Exposição Ambiental/efeitos adversos , Monitoramento Ambiental , Feminino , Fígado/enzimologia , Fígado/metabolismo , Fígado/patologia , Masculino , País de GalesRESUMO
Aldrin, dieldrin, and DDT are chlorinated insecticides that are unintentionally widespread in the environment. It was previously shown that all of the aforementioned compounds increased secretion of ovarian oxytocin (OT), which is a potent uterotonic agent. However, only DDT and its metabolite (DDE) promoted, while aldrin and dieldrin inhibited basal and OT-stimulated myometrial contractions in cows. Therefore, the aim of this study was to determine the effect of these treatments on the reception and further transmission of the OT-signal for myometrial contractions and on the levels of contractile-associated integral proteins (caveolin; CAV) and gap junction proteins (GAPs). Moreover, their effect on reception of signal for the relaxation of myometrium was also studied. Myometrial strips or cells from non-pregnant (8-12 days of oestrous cycle) or late pregnant (5-8 months) cows were incubated with the studied compounds at environmentally relevant dose (10â¯ng/ml), which was chosen according to the previous studies. DDT and DDE increased the CAV protein level, while dieldrin decreased the GAPs level. None of the studied compounds affected mRNA expression of the OT receptor and expression of the second messengers (DAG, IP3, PKC, MLCK). Oppositely, DDE and dieldrin decreased mRNA expression of the relaxin (RLX) receptor. Changes in the amount of contractile-associated integral proteins may be involved in the molecular mechanism underlying the adverse effects of the studied insecticides on myometrial motility. Admittedly, none of the studied compounds impaired the reception or further intracellular transmission of the OT signal to promote contractions during the oestrous cycle, while they showed potential to impair the transmission the signal between cells as well as to diminish the effects of one of the primary inhibitor (RLX) of myometrial contractions during gestation.