Genome-wide DNA methylation profiles of Arsenic exposed subjects through drinking water in Pakistan
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ABSTRACT: Ground water Arsenic (As) toxicity is a global problem and millions of people are exposed to elevated levels (more than WHO advised maximum limit of 10µg/L) through drinking water. The exposure is associated with various cancerous and non-cancerous diseases. It may alter DNA methylation profiles of inviduals and suppress the activity of various genes giving rise to different diseases. Pakistan, a developing country in South Asian region, also has reported elevated ground water As levels in various investigations since 2005. However, a very limited biomonitoring studies have been conducted in this context while no study reports molecular changes associated with drinking water As exposure in Pakistan. Within this context, the present study aimed to investigate genome-wide DNA methylation profiles of the exposed subjects in two districts of Punjab Province Pakistan, i.e Lahore and Kasur. The population was stratified into three exposure groups comprising Low, Medium and High exposure based on their urinary arsenic levels. Genome-wide DNA methylation profiles were obtained using MeDIP in combination with NimbleGen 2.1M Deluxe Promotor arrays.
Project description:Ground water Arsenic toxicity is the global problem and millions of people are exposed to elevated levels through drinking water than WHO permiscible limit of 10µg/L. The exposure is associated with various cancerous and non-cancerous diseases. It may alter the gene expression profile of invidual and suppress the activity of various genes giving rise to different diseases. Pakistan, a developing country in South Asian region, also have different areas reported to have elevated Ground water As. levels since 2005. The Present Study aimed to investigate Transcriptome profile of the exposed subjects in two districts of Punjab Province Pakistan. i.e Lahore and Kasur. The population was stratified into three exposure groups comprising Low, Medium and High exposure based on their urinary arsenic levels. We used Agilent Microarrays platform for Transcriptomics analysis and Linear mixed model was used to find differential gene expression associated with Arsenic exposure
Project description:Exposure to high levels of arsenic in drinking water is associated with several types of cancers including lung, bladder and skin, as well as vascular disease and diabetes. Drinking water standards are based primarily on epidemiology and extrapolation from higher dose experiments, rather than measurements of phenotypic changes associated with chronic exposure to levels of arsenic similar to the current standard of 10ppb, and little is known about the difference between arsenic in food as opposed to arsenic in water. Measurement of phenotypic changes at low doses may be confounded by the effect of laboratory diet, in part because of trace amounts of arsenic in standard laboratory chows, but also because of broad metabolic changes in response to the chow itself. Finally, this series contrasts 8hr, 1mg/kg injected arsenic with the various chronic exposures, and also contrasts the acute effects of arsenic, dexamethasone or their combination. Male C57BL/6 mice were fed on two commercially available laboratory diets (LRD-5001 and AIN-76A) were chronically exposed, through drinking water or food, to environmentally relevant concentrations of sodium arsenite, or acutely exposed to dexamethasone. Keywords: dose response
Project description:Exposure to high levels of arsenic in drinking water is associated with several types of cancers including lung, bladder and skin, as well as vascular disease and diabetes. Drinking water standards are based primarily on epidemiology and extrapolation from higher dose experiments, rather than measurements of phenotypic changes associated with chronic exposure to levels of arsenic similar to the current standard of 10ppb, and little is known about the difference between arsenic in food as opposed to arsenic in water. Measurement of phenotypic changes at low doses may be confounded by the effect of laboratory diet, in part because of trace amounts of arsenic in standard laboratory chows, but also because of broad metabolic changes in response to the chow itself. Finally, this series contrasts 8hr, 1mg/kg injected arsenic with the various chronic exposures, and also contrasts the acute effects of arsenic, dexamethasone or their combination. Male C57BL/6 mice were fed on two commercially available laboratory diets (LRD-5001 and AIN-76A) were chronically exposed, through drinking water or food, to environmentally relevant concentrations of sodium arsenite, or acutely exposed to dexamethasone. Keywords: dose response
Project description:Exposure to high levels of arsenic in drinking water is associated with several types of cancers including lung, bladder and skin, as well as vascular disease and diabetes. Drinking water standards are based primarily on epidemiology and extrapolation from higher dose experiments, rather than measurements of phenotypic changes associated with chronic exposure to levels of arsenic similar to the current standard of 10ppb, and little is known about the difference between arsenic in food as opposed to arsenic in water. Measurement of phenotypic changes at low doses may be confounded by the effect of laboratory diet, in part because of trace amounts of arsenic in standard laboratory chows, but also because of broad metabolic changes in response to the chow itself. Finally, this series contrasts 8hr, 1mg/kg injected arsenic with the various chronic exposures, and also contrasts the acute effects of arsenic, dexamethasone or their combination. Male C57BL/6 mice were fed on two commercially available laboratory diets (LRD-5001 and AIN-76A) were chronically exposed, through drinking water or food, to environmentally relevant concentrations of sodium arsenite, or acutely exposed to dexamethasone. Experiment Overall Design: Male C57BL/6 mice, fed on two commercially available laboratory diets (LRD-5001 and AIN-76A), were chronically exposed through drinking water or food, to environmentally relevant concentrations of sodium arsenite. Another group animals, fed on the AIN 76A diet, was IP injected with dexamethasone (1 mg/kg), sodium arsenite (1mg/kg), both dexamethosone and arsenite, or saline alone.
Project description:Exposure to high levels of arsenic in drinking water is associated with several types of cancers including lung, bladder and skin, as well as vascular disease and diabetes. Drinking water standards are based primarily on epidemiology and extrapolation from higher dose experiments, rather than measurements of phenotypic changes associated with; chronic exposure to levels of arsenic similar to the current standard of 10ppb, and little is known about the difference between arsenic in food as opposed to arsenic in water. Measurement of phenotypic changes at low doses may be confounded by the effect of laboratory diet, in part because of trace amounts of arsenic in standard laboratory chows,; but also because of broad metabolic changes in response to the chow itself. Finally, this series contrasts 8hr, 1mg/kg injected arsenic with the various chronic exposures, and also contrasts the acute effects of arsenic, dexamethasone or their combination. Male C57BL/6 mice were fed on two commercially available laboratory diets (LRD-5001 and AIN-76A) were chronically exposed, through drinking water or food, to environmentally relevant concentrations of sodium arsenite, or acutely exposed to dexamethasone. Experiment Overall Design: Male C57BL/6 mice, fed on two commercially available laboratory diets (LRD-5001 and AIN-76A), were chronically exposed through drinking water or food, to environmentally relevant concentrations of sodium arsenite. Experiment Overall Design: Another group animals, fed on the AIN 76A diet, was IP injected with dexamethasone (1 mg/kg), sodium arsenite (1mg/kg), both dexamethosone and arsenite, or saline alone.
Project description:There is a need to develop biomarkers in alternative testing models predictive for chemically induced chronic disease in humans, preferably describing key events and their relationships in an adverse outcome pathway analysis. Epigenetic modifications, and particularly DNA methylation effects, have been implicated as a major event in susceptibility to develop chronic disease. Arsenic exposure affects large populations around the world through drinking water and industrial activities. We sought to identify epigenetic markers of arsenic exposure. We analyzed the effect of sodium arsenite on DNA methylation in Danio rerio (zebrafish) embryos using unbiased methylation profiling by high throughput sequencing.
Project description:In utero exposure to arsenic via drinking water increases the risk of lower respiratory tract infections during infancy and mortality from bronchiectasis in adulthood. Pregnant mice were exposed to arsenic, and gene expression patterns were profiled in peripheral lung tissue obtained from the offspring at 2 weeks of age. Pregnant Mice (BALB/c, C57BL/6, C3H/HeARC) mice were exposed to arsenic (or control) via drinking water from day 8 of gestation until the birth of their offspring. After giving birth, mothers were given control drinking water. At 2 weeks post-natal age, total RNA was extracted from peripheral lung tissue of the offspring and analysed on Affymetrix microarrays.
Project description:In utero exposure to arsenic via drinking water increases the risk of lower respiratory tract infections during infancy and mortality from bronchiectasis in adulthood. Pregnant mice were exposed to arsenic, and gene expression patterns were profiled in peripheral lung tissue obtained from the offspring at 2 weeks of age.
Project description:Chronic exposure to arsenic is associated with dermatological and non-dermatological disorders. Consumption of arsenic contaminated drinking water results in accumulation of arsenic in liver, spleen, kidneys, lungs and gastrointestinal tract. Although, arsenic is cleared from these sites, a substantial amount of residual arsenic is left in keratin-rich tissues such as skin. Epidemiological studies on arsenic suggest the association of skin cancer upon arsenic exposure, however, the exact mechanism of arsenic induced carcinogenesis is not completely understood. We have developed a cell line-based model to understand the molecular mechanisms involved in arsenic mediated toxicity and carcinogenicity. Human skin keratinocyte cell line, HaCaT was exposed to 100nM sodium arsenite for six months. We observed an increase in the basal ROS levels in arsenic exposed cells along with the increase in anti-apoptotic proteins. SILAC-based quantitative proteomics approach resulted in the identification and quantitation of 2,181 proteins of which 39 proteins were found to be overexpressed (≥2-fold) and 56 downregulated (≤2-fold) upon chronic arsenic exposure. Our study provides comprehensive insights into the molecular basis of chronic arsenic exposure on skin.