Expression data from L3 stage Caernorhabditis elegans after arsenic exposure
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ABSTRACT:
ORGANISM(S): Caenorhabditis elegans
SUBMITTER: Jada Lewis
PROVIDER: E-GEOD-39012 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
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Project description:Background: Arsenite is one of the most toxic chemical substances known and is assumed to exert detrimental effects on viability even at lowest concentrations. By contrast and unlike higher concentrations, we here find that exposure to low-dose arsenite promotes growth of cultured mammalian cells. In the nematode C. elegans, low-dose arsenite promotes resistance against thermal and chemical stressors, and extends lifespan of this metazoan, whereas higher concentrations reduce longevity. While arsenite causes a transient increase in reactive oxygen species (ROS) levels in C. elegans, co-exposure to ROS scavengers prevents the lifespan-extending capabilities of arsenite, indicating that transiently increased ROS levels act as transducers of arsenite effects on lifespan, a process known as mitohormesis. The RNA-seq data comprises 2 biological replicates for worms exposed to 100nM Arsenite 48h after L4 and 2 biological replicates of the same age as controls 4 samples: 2 mRNA profiles of C.elegans 48h after L4 exposed to Arsenite; 2 mRNA profiles of C.elegans 48h after L4 as controls (H20). The N2 wild type (var. Bristol) strain was used.
2013-04-23 | E-GEOD-46257 | biostudies-arrayexpress
Project description:The principal toxicity of acute organophosphate (OP) pesticides poisoning is the disruption of neurotransmission through inhibition of acetylcholinesterase (AChE). However, other mechanisms leading to persistent effects and neurodegeneration remain controversial and difficult to detect. Because Caenorhabditis elegans is relatively resistant to OP lethalityM-bM-^@M-^Tparticularly through the inhibition of AChEM-bM-^@M-^Tstudies in this nematode provide an opportunity to observe alterations in global gene expression following OP exposure that cannot be readily observed in less resistant organisms. We exposed cultures of worms in axenic, defined medium to dichlorvos under three exposure protocols. In the first, worms were exposed continuously throughout the experiment. In the second and third, the worms were exposed for either 2 or 8 h, the dichlorvos was washed out of the culture, and the worms were allowed to recover. We then analyzed gene expression using whole genome microarrays from RNA sampled at multiple time points throughout the exposure. The worms showed a time-dependent response that progressively worsened. Early in the exposure, the predominant effect was on metabolic processes, while at later times, an immune-like response and cellular repair mechanisms dominated the expression pattern. Following removal of dichlorvos, the gene expression in the worms appeared to relatively, rapidly return to steady-state levels. The changes in gene expression observed in the worms following exposure to dichlorvos point towards two potential mechanisms of toxicity: inhibition of AChE and mitochondrial disruption. Synchronized cultures of worms at the L3/L4 molt were treated with dichlorvos (0.6 M-BM-5M or 15 M-BM-5M) or maintained as a controls according to one of three protocols. In the first protocol, the set of flasks was incubated without interruption for the duration of the experiment with flasks being harvested at 2, 8, 14, 20, and 26 h. The other two sets were incubated for 2 or 8 h, at which time the worms were centrifuged out of the exposure medium, washed 3 times with a modified CeHR medium (Washout Buffer), resuspended in fresh CeHR medium without dichlorvos, and returned to the incubator. Flasks were harvested at 6 h intervals following the washout through 26 h. Flasks of worms were also harvested prior to beginning the exposure as the 0 h controls. Total RNA was isolated from the frozen harvested worms then analyzed using Affymetrix GeneChips. A total of 148 microarrays were processed (47 per exposure protocol with 4 replicates) however only 146 were included in final analysis as 2 falied to pass QC criteria.
2013-10-05 | E-GEOD-41366 | biostudies-arrayexpress
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.
2008-10-21 | E-GEOD-11056 | biostudies-arrayexpress
Project description:Arsenic (As) exposure is a significant worldwide environmental health concern. Low dose, chronic arsenic exposure has been associated with higher risk of skin, lung, and bladder cancer, as well as cardiovascular disease and diabetes. While arsenic-induced biological changes play a role in disease pathology, little is known about the dynamic cellular changes due to arsenic exposure and withdrawal. In these studies, we seek to understand the molecular mechanisms behind the biological changes induced by chronic low doses of arsenic exposure. We used a comprehensive approach involving chromatin structural studies and mRNA microarray analyses to determine how chromatin structure and gene expression patterns change in response to chronic low dose arsenic exposure and its subsequent withdrawal. Our results show that cells exposed to low doses of sodium arsenite have distinct temporal and coordinated chromatin, gene expression and miRNA changes that are consistent with differentiation and activation of multiple biochemical pathways. Most of these temporal patterns in gene expression are reversed when arsenic was withdrawn. However, some of the gene expression patterns remained altered, plausibly as a result of an adaptive response by these cells. Additionally, these gene expression patterns correlated with changes in chromatin structure, further solidifying the role of chromatin structure in gene regulatory changes due to arsenite exposure. Lastly, we show that arsenite exposure influences gene regulation both at the transcription initiation as well as at the splicing level. Thus our results suggest that general patterns of alternative splicing, as well as expression of particular gene regulators, can be indicative of arsenite-induced cell transformation. A total of eight (8) samples with two biological replicates under four separate conditions: wild-type treated with deionized H2O for 36 days (NT); chronic low-dose arsenic exposure of 1 uM of sodium arsenite (iAs-T) for 36 days; chronic arsenic exposure of 1 uM of sodium arsenite for 26 days followed by removal of sodium arsenite for 10 days, measured at day 36 (iAs-Rev); and chronic arsenic exposure of 1 uM of sodium arsenite for 26 days, followed by removal of sodium arsenite exposure for 10 days, followed by 1 uM of chronic sodium arsenite exposure for 10 days (measured at day 46) (iAs-Rev-T).
2015-05-05 | E-GEOD-60760 | biostudies-arrayexpress
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.
2008-06-16 | E-GEOD-9630 | biostudies-arrayexpress
Project description:The goal of this study was to identify yeast mutants with arsenite hypersensitivity. Keywords: dose response Matched pools of yeast knockout (YKO) mutants were grown in paired growth media lacking or containing arsenite at various concentrations. The relative abundances of the YKO mutants were profiled using microarrays. Three types of pools were used in this study: (1) heterozygous diploid mutants; (2) haploid mutants obtained as progeny from the heterozygous diploid pool; and (3) haploid mutants also containing a null mutation of the prefoldin gene PFD1.
2010-07-26 | E-GEOD-5973 | biostudies-arrayexpress
Project description:The aim of this study was to determine how gene expression is changed after arsenite-induced malignant transformation of prostate epithelial cells. Gene expression from three distinct passages of untreated, immortal RWPE-1 cells was compared to three timepoints of arsenite-exposed RWPE-1 cells (CAsE-PE) that have undergone malignant transformation.
2013-05-18 | E-GEOD-47047 | biostudies-arrayexpress
Project description:Arsenic is a potent environmental toxin and a cause of numerous health problems. Most studies have assumed that arsenic-induced changes in mRNA levels result from effects on gene transcription. The influence of arsenic on post-transcriptional regulation, another important locus of gene expression control, has remained largely unexplored. To evaluate the prevalence of changes in mRNA stability in response to arsenic in human fibroblasts, we used microarray analyses to determine changes in steady state mRNA levels, and their decay rates, following 24 hour exposure to non-cytotoxic concentrations of sodium arsenite (1 µM). We conclude that arsenite modification of mRNA stability is relatively uncommon, but in some instances can result in significant changes in gene expression. Human BJ diploid foreskin fibroblasts were used in the study. The decay rates of transcripts were determined using actinomycin D to stop transcription after sodium arsenite or water treatment for 24 h. Actinomycin D was added into the culture medium at a final concentration of 5 µg/ml, and treated cells were then harvested at 0, 1, 2, 3 and 4 h for RNA extraction.
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2008-06-16 | E-GEOD-8733 | biostudies-arrayexpress
Project description:Arsenic is methylated during its metabolism, thereby depleting the intracellular methyl donor S-adenosyl-methionine, which may lead to disturbances in DNA methylation patterns which could lead to altered gene expression Cells were exposed to sodium arsenite (NaAsO2, Sigma) at concentrations of 0.08 M-BM-5M, 0.4 M-BM-5M and 2 M-BM-5M for 1, 2 and 8 weeks.
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