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1.
Arch Toxicol ; 98(10): 3241-3257, 2024 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-39192018

RESUMEN

1,4-Dioxane (DX), an emerging water contaminant, is classified as a Group 2B liver carcinogen based on animal studies. Understanding of the mechanisms of action of DX liver carcinogenicity is important for the risk assessment and control of this environmental pollution. Previous studies demonstrate that high-dose DX exposure in mice through drinking water for up to 3 months caused liver mild cytotoxicity and oxidative DNA damage, a process correlating with hepatic CYP2E1 induction and elevated oxidative stress. To access the role of CYP2E1 in DX metabolism and liver toxicity, in the current study, male and female Cyp2e1-null mice were exposed to DX in drinking water (5000 ppm) for 1 week or 3 months. DX metabolism, redox and molecular investigations were subsequently performed on male Cyp2e1-null mice for cross-study comparisons to similarly treated male wildtype (WT) and glutathione (GSH)-deficient Gclm-null mice. Our results show that Cyp2e1-null mice of both genders were resistant to DX-induced hepatocellular cytotoxicity. In male Cyp2e1-null mice exposed to DX for 3 months, firstly, DX metabolism to ß-hydroxyethoxyacetic acid was reduced to ~ 36% of WT levels; secondly, DX-induced hepatic redox dysregulation (lipid peroxidation, GSH oxidation, and activation of NRF2 antioxidant response) was substantially attenuated; thirdly, liver oxidative DNA damage was at a comparable level to DX-exposed WT mice, accompanied by suppression of DNA damage repair response; lastly, no aberrant proliferative or preneoplastic lesions were noted in DX-exposed livers. Overall, this study reveals, for the first time, that CYP2E1 is the main enzyme for DX metabolism at high dose and a primary contributor to DX-induced liver oxidative stress and associated cytotoxicity. High dose DX-induced genotoxicity may occur via CYP2E1-independent pathway(s), potentially involving impaired DNA damage repair.


Asunto(s)
Citocromo P-450 CYP2E1 , Dioxanos , Hígado , Ratones Noqueados , Estrés Oxidativo , Animales , Citocromo P-450 CYP2E1/metabolismo , Citocromo P-450 CYP2E1/genética , Masculino , Femenino , Hígado/efectos de los fármacos , Hígado/metabolismo , Hígado/patología , Dioxanos/toxicidad , Estrés Oxidativo/efectos de los fármacos , Daño del ADN , Ratones , Ratones Endogámicos C57BL , Glutatión/metabolismo , Carcinógenos/toxicidad , Carcinógenos/metabolismo , Enfermedad Hepática Inducida por Sustancias y Drogas/etiología , Enfermedad Hepática Inducida por Sustancias y Drogas/metabolismo , Enfermedad Hepática Inducida por Sustancias y Drogas/genética , Enfermedad Hepática Inducida por Sustancias y Drogas/patología
4.
Dalton Trans ; 51(5): 2083-2093, 2022 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-35048912

RESUMEN

Herein, an amine decorated Cd(II) metal-organic framework (MOF) with a uninodal 6-c topology was synthesized as a suitable platform for facile post-synthetic modification (PSM). The as-synthesized parent d10-MOF (1) with free -NH2 centers, when functionalized with two different carbonyl substituents (1-naphthaldehyde and benzophenone) of varying conjugation, produces two novel luminescent MOFs (LMOFs) viz.PSM-1 and PSM-2. The judicious incorporation of carbonyl substituents into the skeleton of 1 was rationalized via ESI-MS, 1H-NMR, FT-IR and PXRD analyses. Interestingly, both PSM-1 and PSM-2 show 'turn-on' luminescent behaviour in the presence of 1,4-dioxane with the limit of detection (LOD) as 1.079 ppm and 2.487 ppm, respectively, with prompt response time (∼55 s & ∼58 s, respectively). The inhibition of PET is comprehended to be the prime reason for luminescence enhancement upon interaction with the targeted analyte which was further validated from DFT calculations. In continuation, the PSM-MOFs were equally responsive towards 1,4-dioxane in several complex environmental matrices and cosmetic products. Additionally, vapor phase detection of 1,4-dioxane using PSM-MOFs has also been demonstrated as an additional advantage ensuring propagation of future research endeavour.


Asunto(s)
Dioxanos/química , Dioxanos/aislamiento & purificación , Gases/química , Compuestos Organometálicos/química , Agua/química , Aminas , Cadmio/química , Dioxanos/toxicidad , Contaminantes Ambientales/química , Modelos Moleculares , Estructura Molecular
5.
Toxicol Sci ; 183(2): 338-351, 2021 09 28.
Artículo en Inglés | MEDLINE | ID: mdl-33693819

RESUMEN

1,4-Dioxane (1,4-DX) is an environmental contaminant found in drinking water throughout the United States. Although it is a suspected liver carcinogen, there is no federal or state maximum contaminant level for 1,4-DX in drinking water. Very little is known about the mechanisms by which this chemical elicits liver carcinogenicity. In the present study, female BDF-1 mice were exposed to 1,4-DX (0, 50, 500, and 5,000mg/L) in their drinking water for 1 or 4 weeks, to explore the toxic effects. Histopathological studies and a multi-omics approach (transcriptomics and metabolomics) were performed to investigate potential mechanisms of toxicity. Immunohistochemical analysis of the liver revealed increased H2AXγ-positive hepatocytes (a marker of DNA double-strand breaks), and an expansion of precholangiocytes (reflecting both DNA damage and repair mechanisms) after exposure. Liver transcriptomics revealed 1,4-DX-induced perturbations in signaling pathways predicted to impact the oxidative stress response, detoxification, and DNA damage. Liver, kidney, feces, and urine metabolomic profiling revealed no effect of 1,4-DX exposure, and bile acid quantification in liver and feces similarly showed no effect of exposure. We speculate that the results may be reflective of DNA damage being counterbalanced by the repair response, with the net result being a null overall effect on the systemic biochemistry of the exposed mice. Our results show a novel approach for the investigation of environmental chemicals that do not elicit cell death but have activated the repair systems in response to 1,4-DX exposure.


Asunto(s)
Dioxanos , Hígado , Animales , Daño del ADN , Dioxanos/toxicidad , Femenino , Ratones , Análisis de Sistemas
6.
Regul Toxicol Pharmacol ; 119: 104819, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-33189748

RESUMEN

Studies demonstrate that with sufficient dose and duration, 1,4-dioxane (1,4-DX) induces liver tumors in laboratory rodent models. The available evidence aligns with a threshold-dependent, tumor promotion mode of action (MOA). The MOA and key events (KE) in rats are well developed but less so in the mouse. Therefore, we conducted a 90-day drinking water study in female mice to evaluate early KE at 7, 28, and 90 days. Female B6D2F1/Crl mice consumed drinking water containing 0, 40, 200, 600, 2000 or 6000 ppm 1,4-DX. 1,4-DX was detected in blood at 90-days of exposure to 6000 ppm, but not in the other exposure groups, indicating a metabolic clearance threshold between 2000 and 6000. Early events identified in this study include glycogen-like vacuolization, centrilobular hypertrophy, centrilobular GST-P staining, apoptosis, and pan-lobular increase in cell proliferation observed after 90-days of exposure to 6000 ppm 1,4-DX. There was minimal evidence of hepatotoxicity over the duration of this study. These findings demonstrate a previously unreported direct mitogenic response following exposures exceeding the metabolic clearance threshold of 1,4-DX. Collectively, the information generated in this study supports a threshold MOA for the development of liver tumors in mice after exposure to 1,4-DX.


Asunto(s)
Carcinógenos/toxicidad , Dioxanos/toxicidad , Neoplasias Hepáticas/inducido químicamente , Animales , Carcinogénesis/inducido químicamente , Carcinogénesis/patología , Carcinógenos/farmacocinética , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Dioxanos/sangre , Dioxanos/farmacocinética , Relación Dosis-Respuesta a Droga , Agua Potable , Femenino , Hígado/efectos de los fármacos , Hígado/patología , Neoplasias Hepáticas/patología , Ratones , Pruebas de Toxicidad Subcrónica
7.
Proc Jpn Acad Ser B Phys Biol Sci ; 96(5): 180-187, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32389918

RESUMEN

1,4-Dioxane is a genotoxic carcinogen, and its mutagenic properties were recently observed in the liver of guanine phosphoribosyl transferase (gpt) delta transgenic rats. However, the mechanisms of its genotoxicity remain unclear. We analyzed DNA adduct formation in rat livers following 1,4-dioxane treatment. After administering 1,4-dioxane in drinking water at doses of 0, 20, 200, and 5,000 ppm, liver adduct formation was analyzed by DNA adductome analysis. Adducts in treated rat livers were dose-dependently increased compared with those in the control group. Principal component analysis-discriminant analysis (PCA-DA) clearly revealed two clusters of DNA adducts, associated with 0 ppm and low-dose (20 ppm) 1,4-dioxane-treatment versus middle- and high-dose (200, 5,000 ppm)-treated rats. After confirming the intensity of each adduct, three adducts were screened as characteristic of 1,4-dioxane treatment. Two of the three candidates contained thymine or cytidine/uracil moieties. Another candidate was identified as 8-oxo-dG based on mass fragmentation together with high-resolution accurate-mass (HRAM) mass spectrometry data. Oxidative stress responses may partly explain the mechanisms of increased mutations in the liver of gpt delta rats following 1,4-dioxane treatment.


Asunto(s)
Aductos de ADN/metabolismo , Dioxanos/toxicidad , Hígado/efectos de los fármacos , Hígado/metabolismo , Animales , Ratas
10.
Eur J Med Chem ; 176: 310-325, 2019 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-31112892

RESUMEN

A series of compounds generated by ring expansion/opening and molecular elongation/simplification of the 1,3-dioxolane scaffold were prepared and tested for binding affinity at 5-HT1AR and α1 adrenoceptors. The compounds with greater affinity were selected for further functional studies. N-((2,2-diphenyl-1,3-dioxan-5-yl)methyl)-2-(2-methoxyphenoxy)ethan-1-ammonium hydrogen oxalate (12) emerged as highly potent full agonist at the 5-HT1AR (pKi 5-HT1A = 8.8; pD2 = 9.22, %Emax = 92). The pharmacokinetic data in rats showed that the orally administered 12 has a high biodistribution in the brain compartment. Thus, 12 was further investigated in-vivo, showing an anxiolytic and antidepressant effect. Moreover, in the formalin test, 12 was able to decrease the late response to the noxious stimulus, indicating a potential use in the treatment of chronic pain.


Asunto(s)
Analgésicos/uso terapéutico , Ansiolíticos/uso terapéutico , Antidepresivos/uso terapéutico , Dioxanos/uso terapéutico , Fármacos Neuroprotectores/uso terapéutico , Agonistas del Receptor de Serotonina 5-HT1/uso terapéutico , Analgésicos/síntesis química , Analgésicos/farmacocinética , Analgésicos/toxicidad , Animales , Ansiolíticos/síntesis química , Ansiolíticos/farmacocinética , Ansiolíticos/toxicidad , Antidepresivos/síntesis química , Antidepresivos/farmacocinética , Antidepresivos/toxicidad , Encéfalo/metabolismo , Dioxanos/síntesis química , Dioxanos/farmacocinética , Dioxanos/toxicidad , Masculino , Fármacos Neuroprotectores/síntesis química , Fármacos Neuroprotectores/farmacocinética , Fármacos Neuroprotectores/toxicidad , Ratas Sprague-Dawley , Receptor de Serotonina 5-HT1A/metabolismo , Receptores Adrenérgicos alfa 1/metabolismo , Agonistas del Receptor de Serotonina 5-HT1/síntesis química , Agonistas del Receptor de Serotonina 5-HT1/farmacocinética , Agonistas del Receptor de Serotonina 5-HT1/toxicidad , Estereoisomerismo , Relación Estructura-Actividad
11.
Chemosphere ; 228: 149-158, 2019 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-31029960

RESUMEN

1,4-Dioxane (dioxane), an industrial solvent widely detected in environmental and biological matrices, has potential nephrotoxicity. However, the underlying mechanism by which dioxane induces kidney damage remains unclear. In this study, we used an integrated approach, combining kidney transcriptomics and urine metabolomics, to explore the mechanism for the toxic effects of dioxane on the mouse kidney. Transcriptomics profiling showed that exposure to 0.5 mg/L dioxane induced perturbations of multiple signaling pathways in kidneys, such as MAPK and Wnt, although no changes in oxidative stress indicators or anatomical pathology were observed. Exposure to 500 mg/L dioxane significantly disrupted various metabolic pathways, concomitantly with observed renal tissue damage and stimulated oxidant defense system. Urine metabolomic analysis using NMR indicated that exposure to dioxane gradually altered the metabolic profile of urine. Within the full range of altered metabolites, the metabolic pathway containing glycine, serine and threonine was the most significantly altered pathway at the early stage of exposure (3 weeks) in both 0.5 and 500 mg/L dioxane-treated groups. However, with prolonged exposure (9 and 12 weeks), the level of taurine significantly decreased after treatment of 0.5 mg/L dioxane, while exposure to 500 mg/L dioxane significantly increased glutathione levels in urine and decreased arginine metabolism. Furthermore, integrated omics analysis showed that 500 mg/L dioxane exposure induced arginine deficiency by perturbing several genes involved in renal arginine metabolism. Shortage of arginine coupled with increased oxidative stress could lead to renal dysfunction. These findings offer novel insights into the toxicity of dioxane.


Asunto(s)
Dioxanos/toxicidad , Riñón/lesiones , Redes y Vías Metabólicas , Animales , Arginina/deficiencia , Perfilación de la Expresión Génica/métodos , Riñón/efectos de los fármacos , Enfermedades Renales/inducido químicamente , Enfermedades Renales/genética , Enfermedades Renales/orina , Masculino , Metaboloma/efectos de los fármacos , Metabolómica/métodos , Ratones , Solventes/toxicidad , Orina/química
12.
Artículo en Inglés | MEDLINE | ID: mdl-30595213

RESUMEN

1,4-Dioxane, used widely as a solvent in the manufacture of chemicals and as a laboratory reagent, induced liver adenomas and carcinomas in mice and rats, and nasal tumors in rats in several long-term studies. 1,4-Dioxane has been reported to be non-genotoxic in vitro, and there is no clear conclusion concerning its in vivo genotoxicity in rodents. In the present study, we investigated the ability of 1,4-dioxane to induce micronuclei in the liver and bone marrow of rats. For the liver micronucleus test, we performed the juvenile animal method and two methods using partial hepatectomy (PH), dosing before PH or dosing after PH. We also evaluated the in vivo mutagenicity of 1,4-dioxane by Pig-a gene mutation assay using rat peripheral blood. As a result, all methods of liver micronucleus test showed an increase in the frequency of micronucleated hepatocytes by 1,4-dioxane. The dosing before PH, a suitable method for detecting structural chromosome aberration inducers, showed the clearest response for micronucleated hepatocytes induction among the three methods. This finding is consistent with a previous report that 1,4-dioxane induces mainly chromosome breakage in the liver. Negative results were obtained in the bone marrow micronucleus test and Pig-a gene mutation assay in our study. These results suggested that 1,4-dioxane is clastogenic in the liver but not genotoxic in the bone marrow of rats.


Asunto(s)
Médula Ósea/patología , Dioxanos/toxicidad , Hígado/patología , Proteínas de la Membrana/análisis , Pruebas de Micronúcleos , Mutágenos/toxicidad , Animales , Células de la Médula Ósea/patología , Rotura Cromosómica/efectos de los fármacos , Hepatocitos/patología , Masculino , Ratas , Ratas Endogámicas F344
13.
Environ Pollut ; 243(Pt A): 573-581, 2018 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-30216889

RESUMEN

Biodegradation of 1,4-dioxane was examined in packed quartz and soil column flow-through systems. The inhibitory effects of co-contaminants, specifically trichloroethene (TCE), 1,1-dichloroethene (1,1-DCE), and copper (Cu2+) ions, were investigated in the columns either with or without bioaugmentation with a 1,4-dioxane degrading bacterium Pseudonocardia dioxanivorans CB1190. Results indicate that CB1190 cells readily grew and colonized in the columns, leading to significant degradation of 1,4-dioxane under oxic conditions. Degradation of 1,4-dioxane was also observed in the native soil (without bioaugmentation), which had been previously subjected to enhanced reductive dechlorination treatment for co-contaminants TCE and 1,1-DCE. Bioaugmentation of the soil with CB1190 resulted in nearly complete degradation at influent concentrations of 3-10 mg L-1 1,4-dioxane and a residence reaction time of 40-80 h, but the presence of co-contaminants, 1,1-DCE and Cu2+ ions (up to 10 mg L-1), partially inhibited 1,4-dioxane degradation in the untreated and bioaugmented soil columns. However, the inhibitory effects were much less severe in the column flow-through systems than those previously observed in planktonic cultures, which showed near complete inhibition at the same co-contaminant concentrations. These observations demonstrate a low susceptibility of soil microbes to the toxicity of 1,1-DCE and Cu2+ in packed soil flow-through systems, and thus have important implications for predicting biodegradation potential and developing sustainable, cost-effective technologies for in situ remediation of 1,4-dioxane contaminated soils and groundwater.


Asunto(s)
Biodegradación Ambiental/efectos de los fármacos , Dioxanos/toxicidad , Contaminantes Químicos del Agua/toxicidad , Agua Subterránea/microbiología , Halogenación , Suelo/química , Tricloroetileno
14.
Artículo en Inglés | MEDLINE | ID: mdl-30173864

RESUMEN

It has long been unclear whether 1,4-dioxane (DO) is a genotoxic hepatocarcinogen (GTHC). Therefore, the present study aimed to evaluate rat GTHCs and non-genotoxic hepatocarcinogens (NGTHCs) via selected gene expression patterns in the liver, as determined by next generation sequencing-targeted mRNA sequencing (RNA-Seq) and principal component analysis (PCA). Previously, we selected 11 marker genes (Aen, Bax, Btg2, Ccnf, Ccng1, Cdkn1a, Lrp1, Mbd1, Phlda3, Plk2, and Tubb4b) to discriminate GTHCs and NGTHCs. In the present study, we quantified changes in the expression of these genes following DO treatment, and compared them with treatment with two typical rat GTHCs, N-nitrosodiethylamine (DEN) and 3,3'-dimethylbenzidine·2HCl (DMB), and a typical rat NGTHC, di(2-ethylhexyl)phthalate (DEHP). RNA-Seq was conducted on liver samples from groups of five male, 10-week-old F344 rats after 4 weeks' feeding of chemicals in the water or the food. Rats in the control group were given water and a basal diet. Significant changes in gene expression in experimental groups compared with the control group were observed in eight genes (Aen, Bax, Btg2, Ccnf, Ccng1, Cdkn1a, Phlda3 and Plk2), as shown by Tukey's test. Gene expression profiles of the 11 genes under DO treatment differed significantly from those with DEN and DMB, as well as DEHP. Gene expression profiles with DO treatment differed partially from those with typical GTHCs for five genes (Bax, Btg2, Cdkn1a, Lrp1 and Plk2) and were substantially different from treatment with a typical NGTHC (DEHP) for nine genes (Aen, Bax, Btg2, Ccnf, Ccng1, Cdkn1a, Mbd1, Phlda3 and Tubb4b) as determined by Tukey's test. Finally, PCA successfully differentiated GTHCs from DEHP and DO with the 11 genes. The present results suggest that RNA-Seq and PCA are useful to evaluate rat typical GTHCs and typical NGTHCs. DO was suggested to result in a different intermediate gene expression profile from typical GTHCs and NGTHC.


Asunto(s)
Biomarcadores de Tumor/genética , Carcinogénesis/inducido químicamente , Carcinogénesis/patología , Carcinógenos/toxicidad , Dioxanos/toxicidad , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Secuenciación de Nucleótidos de Alto Rendimiento/métodos , Neoplasias Hepáticas Experimentales/inducido químicamente , Neoplasias Hepáticas Experimentales/patología , Animales , Carcinogénesis/genética , Neoplasias Hepáticas Experimentales/genética , Masculino , Ratas , Ratas Endogámicas F344
15.
Arch Toxicol ; 92(10): 3207-3221, 2018 10.
Artículo en Inglés | MEDLINE | ID: mdl-30155721

RESUMEN

1,4-Dioxane is a widely used synthetic industrial chemical and its contamination of drinking water and food is a potential health concern. It induces liver tumors when administered in the drinking water to rats and mice. However, the mode of action (MOA) of the hepatocarcinogenicity of 1,4-dioxane remains unclear. Importantly, it is unknown if 1,4-dioxane is genotoxic, a key consideration for risk assessment. To determine the in vivo mutagenicity of 1,4-dioxane, gpt delta transgenic F344 rats were administered 1,4-dioxane at various doses in the drinking water for 16 weeks. The overall mutation frequency (MF) and A:T- to -G:C transitions and A:T- to -T:A transversions in the gpt transgene were significantly increased by administration of 5000 ppm 1,4-dioxane. A:T- to -T:A transversions were also significantly increased by administration of 1000 ppm 1,4-dioxane. Furthermore, the DNA repair enzyme MGMT was significantly induced at 5000 ppm 1,4-dioxane, implying that extensive genetic damage exceeded the repair capacity of the cells in the liver and consequently led to liver carcinogenesis. No evidence supporting other MOAs, including induction of oxidative stress, cytotoxicity, or nuclear receptor activation, that could contribute to the carcinogenic effects of 1,4-dioxane were found. These findings demonstrate that 1,4-dioxane is a genotoxic hepatocarcinogen and induces hepatocarcinogenesis through a mutagenic MOA in rats. Because our data indicate that 1,4-dioxane is a genotoxic carcinogen, we estimated the point of departure of the mutagenicity and carcinogenicity of 1,4-dioxane using the no-observed effect-level approach and the Benchmark dose approach to characterize its dose-response relationship at low doses.


Asunto(s)
Carcinógenos/toxicidad , Dioxanos/toxicidad , Hígado/efectos de los fármacos , Mutágenos/toxicidad , 8-Hidroxi-2'-Desoxicoguanosina , Animales , Pruebas de Carcinogenicidad , Desoxiguanosina/análogos & derivados , Desoxiguanosina/metabolismo , Dioxanos/administración & dosificación , Relación Dosis-Respuesta a Droga , Regulación de la Expresión Génica/efectos de los fármacos , Glutatión Transferasa/genética , Hígado/patología , Masculino , Pruebas de Mutagenicidad , Mutágenos/administración & dosificación , Nivel sin Efectos Adversos Observados , Ratas Endogámicas F344 , Ratas Transgénicas
16.
Environ Sci Pollut Res Int ; 25(27): 27274-27282, 2018 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-30032369

RESUMEN

1,4-Dioxane is an emerging pollutant, which widely exists in natural environments and poses potential risks to the living organisms. However, its effect on the denitrification process is still unknown. In this study, the effects of 1,4-dioxane on the denitrification process were therefore investigated by using Paracoccus denitrificans as the model denitrifier. The obtained results showed that the exposure of 1,4-dioxane exhibited remarkable lag or inhibition on the denitrification process, especially with high dose. In the control without 1,4-dioxane exposure, Paracoccus denitrificans showed high denitrification efficiency (98.5%). However, the efficiency decreased to 78.5, 63.9, and 9.3% with 0.50, 0.75, and 1.0% (v/v) 1,4-dioxane dose, respectively. The dose-induced inhibition of denitrification by 1,4-dioxane could be partially attributed to the negative effects on proliferation and viability of functional microorganisms by conjugating and disrupting the cell membranes. Furthermore, 1,4-dioxane caused biotoxicity to the intracellular activities of denitrifiers via disturbing carbon source utilization and interfering the key enzymes responsible for glycolysis. The decrease of microbial viability and activity inevitably resulted in the decline of key enzymes (NAR, NIR, NOR, and N2OR) closely related with denitrification process, which could be the direct reason for the decrease of denitrification performance.


Asunto(s)
Desnitrificación/efectos de los fármacos , Dioxanos/toxicidad , Contaminantes Ambientales/toxicidad , Nitratos/metabolismo , Paracoccus denitrificans/efectos de los fármacos , Glucólisis/efectos de los fármacos , Paracoccus denitrificans/metabolismo
17.
Environ Health Perspect ; 126(3): 037004, 2018 03 12.
Artículo en Inglés | MEDLINE | ID: mdl-29553459

RESUMEN

BACKGROUND: Previous studies have reported associations of perinatal exposure to air toxics, including some metals and volatile organic compounds, with autism spectrum disorder (ASD). OBJECTIVES: Our goal was to further explore associations of perinatal air toxics with ASD and associated quantitative traits in high-risk multiplex families. METHODS: We included participants of a U.S. family-based study [the Autism Genetic Resource Exchange (AGRE)] who were born between 1994 and 2007 and had address information. We assessed associations between average annual concentrations at birth for each of 155 air toxics from the U.S. EPA emissions-based National-scale Air Toxics Assessment and a) ASD diagnosis (1,540 cases and 477 controls); b) a continuous measure of autism-related traits, the Social Responsiveness Scale (SRS, among 1,272 cases and controls); and c) a measure of autism severity, the Calibrated Severity Score (among 1,380 cases). In addition to the individual's air toxic level, mixed models (clustering on family) included the family mean air toxic level, birth year, and census covariates, with consideration of the false discovery rate. RESULTS: ASD diagnosis was positively associated with propionaldehyde, methyl tert-butyl ether (MTBE), bromoform, 1,4-dioxane, dibenzofurans, and glycol ethers and was inversely associated with 1,4-dichlorobenzene, 4,4'-methylene diphenyl diisocyanate (MDI), benzidine, and ethyl carbamate (urethane). These associations were robust to adjustment in two-pollutant models. Autism severity was associated positively with carbon disulfide and chlorobenzene, and negatively with 1,4-dichlorobenzene. There were no associations with the SRS. CONCLUSIONS: Some air toxics were associated with ASD risk and severity, including some traffic-related air pollutants and newly-reported associations, but other previously reported associations with metals and volatile organic compounds were not reproducible. https://doi.org/10.1289/EHP1867.


Asunto(s)
Trastorno Autístico/epidemiología , Contaminantes Atmosféricos/toxicidad , Aldehídos , Trastorno del Espectro Autista/epidemiología , Trastorno del Espectro Autista/genética , Trastorno Autístico/etiología , Bencidinas/toxicidad , Clorobencenos/toxicidad , Dioxanos/toxicidad , Exposición a Riesgos Ambientales/efectos adversos , Femenino , Humanos , Masculino , Éteres Metílicos/toxicidad , Trihalometanos/toxicidad , Uretano/toxicidad
18.
ACS Chem Biol ; 12(10): 2538-2545, 2017 10 20.
Artículo en Inglés | MEDLINE | ID: mdl-28837769

RESUMEN

Two aromatic amines (ferrostatin-1 and liproxstatin-1) were recently identified from high-throughput screening efforts to uncover potent inhibitors of ferroptosis, the necrotic-like cell death induced by inhibition of glutathione peroxidase 4 (GPX4), deletion of the corresponding gpx4 gene, or starvation of GPX4 of its reducing cosubstrate, glutathione (GSH). We have since demonstrated that these two aromatic amines are highly effective radical-trapping antioxidants (RTAs) in lipid bilayers, suggesting that they subvert ferroptosis by inhibiting lipid peroxidation (autoxidation) and, thus, that this process drives the execution of ferroptosis. Herein, we show that diarylamine RTAs used to protect petroleum-derived products from autoxidation can be potent inhibitors of ferroptosis. The diarylamines investigated include representative examples of additives to engine oils, greases and rubber (4,4'-dialkyldiphenylamines), core structures of dyes and pharmaceuticals (phenoxazines and phenothiazines), and aza-analogues of these three classes of compounds that we have recently shown can be modified to achieve much greater reactivity. We find that regardless of how ferroptosis is induced (GPX4 inhibition, gpx4 deletion or GSH depletion), compounds which possess good RTA activity in organic solution (kinh > 105 M-1 s-1) and lipid bilayers (kinh > 104 M-1 s-1) are generally potent inhibitors of ferroptosis (in mouse embryonic fibroblasts). Likewise, structural analogs that do not possess RTA activity are devoid of antiferroptotic activity. These results further support the argument that lipid peroxidation (autoxidation) plays a major role in the mechanism of cell death induced by either GPX4 inhibition, gpx4 deletion, or GSH depletion. Moreover, it offers clear direction that ongoing medicinal chemistry efforts on liproxstatin and ferrostatin derivatives, which have been proposed as lead compounds for the treatment and/or prevention of ischemia/reperfusion injury, renal failure, and neurodegeneration, can be widened to include other aminic RTAs. To aid in these efforts, some relevant structure-reactivity relationships are discussed.


Asunto(s)
Aminas/química , Antioxidantes/química , Antioxidantes/farmacología , Autofagia/efectos de los fármacos , Glutatión Peroxidasa/antagonistas & inhibidores , Animales , Apoptosis/efectos de los fármacos , Autofagia/fisiología , Línea Celular , Supervivencia Celular , Dioxanos/toxicidad , Fibroblastos/efectos de los fármacos , Eliminación de Gen , Regulación Enzimológica de la Expresión Génica , Glutatión Peroxidasa/genética , Glutatión Peroxidasa/metabolismo , Humanos , Peroxidación de Lípido/fisiología , Liposomas , Ratones , Oxidación-Reducción , Fosfolípido Hidroperóxido Glutatión Peroxidasa
19.
Regul Toxicol Pharmacol ; 88: 45-55, 2017 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-28366800

RESUMEN

Previous work has shown that the weight of evidence supports the hypothesis that 1,4-dioxane causes liver tumors in rodents through cytotoxicity and subsequent regenerative hyperplasia. Questions regarding a lack of concordant findings for this mode of action (MOA) in mice have not been resolved, however. In the current work, a reanalysis of data from two chronic mouse cancer bioassays on 1,4-dioxane, one 13-week mouse study, seven rat cancer bioassays, coupled with other data such as 1,4-dioxane's negative mutagenicity, its lack of up-regulated DNA repair, and the appearance of liver tumors with a high background incidence, support the conclusion that rodent liver tumors, including those in mice, are evoked by a regenerative hyperplasia MOA. The initiating event for this MOA is metabolic saturation of 1,4-dioxane. Above metabolic saturation, higher doses of the parent compound cause an ever increasing toxicity in the rodent liver as evidenced by higher blood levels of enzymes indicative of liver cell damage and associated histopathology that occurs in a dose and time related manner. Importantly, alternative modes of action can be excluded. The observed liver toxicity has a threshold in the dose scale at or below levels that saturate metabolism, and generally in the range of 9.6-42 mg/kg-day for rats and 57 to 66 mg/kg-day for mice. It follows that threshold approaches to the assessment of this chemical's toxicity are supported by the non-mutagenic, metabolic saturation kinetics, and cytotoxicity-generated regenerative repair information available for 1,4-dioxane promoted rodent liver tumors.


Asunto(s)
Dioxanos/toxicidad , Neoplasias Hepáticas Experimentales/inducido químicamente , Hígado/efectos de los fármacos , Mutágenos/toxicidad , Animales , Hiperplasia/inducido químicamente , Hígado/patología , Neoplasias Hepáticas Experimentales/patología , Regeneración Hepática , Ratones , Ratas , Medición de Riesgo , Especificidad de la Especie
20.
J Egypt Soc Parasitol ; 46(1): 135-43, 2016 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-27363050

RESUMEN

1,4-Dioxane (DX) with two oxygen atoms make it hydrophilic and infinitely soluble in water. As a synthetic organic compound, it used widely throughout industry as a solvent. Dioxane causes numerous human ailments such as liver damage and kidney failure. It has been shown in research to be carcinogenic to animals, and is a potential carcinogen to humans. Daily administration for 1,4-dioxane (100 mg/kg body weight) in drinking water for rats weighing 120 g, except for normal control group. Experimental animal for 42 days was followed through body weight, serum alkaline phosphatase, serum creatinine, malondialdehyde, and catalase enzyme activity; beside histological patterns for liver, kidney, brain and ovary sections. Protection treatment has been offered using oral injection N-acetyl cysteine (100 mg/kg b.wt.), and fresh 200 mg/kg b.wt. in diet meal for each of nabk, husk, and sycamore in separated groups. Body weight and CAT activity have decreased by 25.8, and 68.7%, respectively. While increase has found in MDA, ALP and creatinine values by 76, 48.9, and 67.3%, respectively. NAC showed improvement especially for MDA peroxidation marker and creatinine for kidney disorder. On the other hand, nabk improved CAT activity and husk for ALP liver mutagenicity marker. Intoxicated DX showed edema, kupffer cell activation, atrophy of glomerular tuft, and necrosis of neurons in liver, kidney and brain sections. Obviously nabk showed highly improvement in liver toxicity which is the most sensitive organ to DX as found in research.


Asunto(s)
Dioxanos/toxicidad , Estrés Oxidativo/efectos de los fármacos , Plantas Comestibles , Acetilcisteína/farmacología , Animales , Encéfalo/efectos de los fármacos , Catalasa/metabolismo , Relación Dosis-Respuesta a Droga , Contaminantes Ambientales/toxicidad , Femenino , Hígado/efectos de los fármacos , Hígado/enzimología , Malondialdehído/metabolismo , Ovario/efectos de los fármacos , Ratas , Ratas Sprague-Dawley
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