ABSTRACT: The present study used microarray expression profiling to determine the effects of embryonic arsenic exposure. Fertilized killifish (Fundulus heteroclitus) eggs were exposed to 0, 5, 15, or 25ppm arsenic as sodium arsenite. To examine differentially expressed genes, the microarrays were probed using RNA obtained from the control and 25ppm-exposed killifish just after hatching. No differences were noted in survival or hatching success between any of the groups. After analysis, a set of 332 genes was found to accurately distinguish between the control and 25ppm exposure groups. Expression of several of the genes (CDBP1, Arts1, FetB, and Fbp7) was quantified by qPCR in the lower exposure groups and at earlier time points to examine temporal and dose-responsive expression patterns. These results will enable us to better understand how arsenic impacts development. Killifish eggs were fertilized, divided into petri dishes containing 40 eggs (n=10 replicate petri dishes), and cultured until hatch in 0 or 25 ppm arsenic as sodium arsenite. Four to five hatchlings within each petri dish were pooled to obtain RNA. A total of 20 arrays were probed, 10 with RNA from control fish and 10 with RNA from the arsenic-exposed fish.
Project description:The present study used microarray expression profiling to determine the effects of embryonic arsenic exposure. Fertilized killifish (Fundulus heteroclitus) eggs were exposed to 0, 5, 15, or 25ppm arsenic as sodium arsenite. To examine differentially expressed genes, the microarrays were probed using RNA obtained from the control and 25ppm-exposed killifish just after hatching. No differences were noted in survival or hatching success between any of the groups. After analysis, a set of 332 genes was found to accurately distinguish between the control and 25ppm exposure groups. Expression of several of the genes (CDBP1, Arts1, FetB, and Fbp7) was quantified by qPCR in the lower exposure groups and at earlier time points to examine temporal and dose-responsive expression patterns. These results will enable us to better understand how arsenic impacts development.
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).
Project description:Human m6A-mRNA&lncRNA Epitranscriptomic Microarray of arsenite-transformed human keratinocytes (HaCaT-T cells, 1 μM arsenite exposure for 50 passages) compared to its control HaCaT cells (passed for 50 passages without arsenic exposure).
Project description:Talemi2014 - Arsenic toxicity and
detoxification mechanisms in yeast
The model implements arsenite (AsIII)
transport regulation, its distribution within main cellular AsIII
pools and detoxification. The intracellular As pools considered are
free AsIII (AsIIIin), protein-bound AsIII (AsIIIprot), glutathione
conjugated AsIII (AsGS3) and vacuolar sequestered AsIII (vAsGS3).
This model is described in the article:
Mathematical modelling of
arsenic transport, distribution and detoxification processes in
yeast.
Talemi SR, Jacobson T, Garla V,
Navarrete C, Wagner A, Tamás MJ, Schaber J.
Mol. Microbiol. 2014 Jun; 92(6):
1343-1356
Abstract:
Arsenic has a dual role as causative and curative agent of
human disease. Therefore, there is considerable interest in
elucidating arsenic toxicity and detoxification mechanisms. By
an ensemble modelling approach, we identified a best
parsimonious mathematical model which recapitulates and
predicts intracellular arsenic dynamics for different
conditions and mutants, thereby providing novel insights into
arsenic toxicity and detoxification mechanisms in yeast, which
could partly be confirmed experimentally by dedicated
experiments. Specifically, our analyses suggest that: (i)
arsenic is mainly protein-bound during short-term (acute)
exposure, whereas glutathione-conjugated arsenic dominates
during long-term (chronic) exposure, (ii) arsenic is not stably
retained, but can leave the vacuole via an export mechanism,
and (iii) Fps1 is controlled by Hog1-dependent and
Hog1-independent mechanisms during arsenite stress. Our results
challenge glutathione depletion as a key mechanism for arsenic
toxicity and instead suggest that (iv) increased glutathione
biosynthesis protects the proteome against the damaging effects
of arsenic and that (v) widespread protein inactivation
contributes to the toxicity of this metalloid. Our work in
yeast may prove useful to elucidate similar mechanisms in
higher eukaryotes and have implications for the use of arsenic
in medical therapy.
This model is hosted on
BioModels Database
and identified by:
BIOMD0000000547.
To cite BioModels Database, please use:
BioModels Database:
An enhanced, curated and annotated resource for published
quantitative kinetic models.
To the extent possible under law, all copyright and related or
neighbouring rights to this encoded model have been dedicated to
the public domain worldwide. Please refer to
CC0
Public Domain Dedication for more information.
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.
Project description:The present study investigated arsenicâs effects on mummichogs (Fundulus heteroclitus), while also examining what role that gender or age of exposure might play. Adult male and female mummichogs were exposed to 172ppb, 575ppb, or 1,720ppb arsenic as sodium arsenite for 10 days immediately prior to spawning. No differences were noted in the number or viability of eggs between the groups, but there was a significant increase in deformities in the 1,720ppb arsenic exposure group. Total RNA from adult livers or 6-week-old juveniles was used to probe custom macroarrays for changes in gene expression. In females, 3% of the genes were commonly differentially expressed in the 172 and 575ppb exposure groups. In the males, between 1.1-3% of the differentially expressed genes were in common between the exposure groups. Several genes, including apolipoprotein, serum amyloid precursor, lysozyme, and tributyltin-binding protein, were commonly expressed in either a dose-responsive or dose-specific, but across genders, manner. These patterns of regulation were confirmed by QPCR. These findings will provide us with a better understanding of the effects of dose, gender, and exposure age on the response to arsenic. Adult mummichogs (Fundulus heteroclitus) were exposed to either 0 or 1,720ppb sodium arsenite for 10 days before the full moon. Each treatment group had 5 20-gallon plastic tanks with 2 male and 5 female fish per tank. The fish were exposed via a static renewal, with renewals every 48 hours. Mummichogs were housed at 25C in a 14/10 light/dark cycle at 18% salinity. On the 3 days surrounding the full moon, spawning substrates were provided and eggs collected. Adult males: After the last day of egg collection, the adults were euthanized. The livers were removed from the males, placed in TRI-Reagent® for RNA isolation (Sigma Chemical Co, St. Louis, MO), and then stored at -80C. Juveniles: Eggs were transferred to clean water and allowed to hatch. The juveniles were grown out in clean water for 6 weeks and then were euthanized. Whole juveniles (7-10 per exposure per tank) were placed in TRI-Reagent® for RNA isolation (Sigma Chemical Co, St. Louis, MO), and then stored at -80C.
Project description:The present study investigated arsenicâs effects on mummichogs (Fundulus heteroclitus), while also examining what role that gender or age of exposure might play. Adult male and female mummichogs were exposed to 172ppb, 575ppb, or 1,720ppb arsenic as sodium arsenite for 10 days immediately prior to spawning. No differences were noted in the number or viability of eggs between the groups, but there was a significant increase in deformities in the 1,720ppb arsenic exposure group. Total RNA from adult livers or 6-week-old juveniles was used to probe custom macroarrays for changes in gene expression. In females, 3% of the genes were commonly differentially expressed in the 172 and 575ppb exposure groups. In the males, between 1.1-3% of the differentially expressed genes were in common between the exposure groups. Several genes, including apolipoprotein, serum amyloid precursor, lysozyme, and tributyltin-binding protein, were commonly expressed in either a dose-responsive or dose-specific, but across genders, manner. These patterns of regulation were confirmed by QPCR. These findings will provide us with a better understanding of the effects of dose, gender, and exposure age on the response to arsenic. Adult mummichogs (Fundulus heteroclitus) were exposed to either 0 or 172ppb sodium arsenite for 10 days before the full moon. Each treatment group had 5 20-gallon plastic tanks with 2 male and 5 female fish per tank. The fish were exposed via a static renewal, with renewals every 48 hours. Mummichogs were housed at 25C in a 14/10 light/dark cycle at 18% salinity. On the 3 days surrounding the full moon, spawning substrates were provided and eggs collected. Adult males and females: After the last day of egg collection, the adults were euthanized. The livers were removed from the males and females, placed in TRI-Reagent® for RNA isolation (Sigma Chemical Co, St. Louis, MO), and then stored at -80C. Juveniles: Eggs were transferred to clean water and allowed to hatch. The juveniles were grown out in clean water for 6 weeks and then were euthanized. Whole juveniles (7-10 per exposure per tank) were placed in TRI-Reagent® for RNA isolation (Sigma Chemical Co, St. Louis, MO), and then stored at -80C.
Project description:The present study investigated arsenicâs effects on mummichogs (Fundulus heteroclitus), while also examining what role that gender or age of exposure might play. Adult male and female mummichogs were exposed to 172ppb, 575ppb, or 1,720ppb arsenic as sodium arsenite for 10 days immediately prior to spawning. No differences were noted in the number or viability of eggs between the groups, but there was a significant increase in deformities in the 1,720ppb arsenic exposure group. Total RNA from adult livers or 6-week-old juveniles was used to probe custom macroarrays for changes in gene expression. In females, 3% of the genes were commonly differentially expressed in the 172 and 575ppb exposure groups. In the males, between 1.1-3% of the differentially expressed genes were in common between the exposure groups. Several genes, including apolipoprotein, serum amyloid precursor, lysozyme, and tributyltin-binding protein, were commonly expressed in either a dose-responsive or dose-specific, but across genders, manner. These patterns of regulation were confirmed by QPCR. These findings will provide us with a better understanding of the effects of dose, gender, and exposure age on the response to arsenic. Adult mummichogs (Fundulus heteroclitus) were exposed to either 0 or 172ppb sodium arsenite for 10 days before the full moon. Each treatment group had 5 20-gallon plastic tanks with 2 male and 5 female fish per tank. The fish were exposed via a static renewal, with renewals every 48 hours. Mummichogs were housed at 25C in a 14/10 light/dark cycle at 18% salinity. On the 3 days surrounding the full moon, spawning substrates were provided and eggs collected. Adult males and females: After the last day of egg collection, the adults were euthanized. The livers were removed from the males and females, placed in TRI-Reagent® for RNA isolation (Sigma Chemical Co, St. Louis, MO), and then stored at -80C. Juveniles: Eggs were transferred to clean water and allowed to hatch. The juveniles were grown out in clean water for 6 weeks and then were euthanized. Whole juveniles (7-10 per exposure per tank) were placed in TRI-Reagent® for RNA isolation (Sigma Chemical Co, St. Louis, MO), and then stored at -80C.
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:Arsenic contamination in food and ground water constitutes a public health concern to more than 100 million people worldwide. Individuals chronically exposed to arsenic through drinking and ingestion exhibit a higher risk in developing cancers and cardiovascular diseases. Nevertheless, the underlying mechanisms of arsenic toxicity are not fully understood. Arsenite is known to bind to and deactivate RING finger E3 ubiquitin ligases; thus, we reason that a systematic interrogation about how arsenite exposure modulates global protein ubiquitination may reveal novel molecular targets for arsenic toxicity. By employing liquid chromatography-tandem mass spectrometry, in combination with stable isotope labeling by amino acids in cell culture (SILAC) and immunoprecipitation of di-glycine-conjugated lysine-containing tryptic peptides, we assessed the alterations in protein ubiquitination in GM00637 human skin fibroblast cells upon arsenite exposure at the entire proteome level. We observed that arsenite exposure led to altered ubiquitination of many proteins, where the alterations in a large majority of ubiquitination events are negatively correlated with changes in expression of the corresponding proteins, suggesting their modulation by the ubiquitin-proteasomal pathway. Moreover, we observed that arsenite exposure confers diminished ubiquitination of a rate-limiting enzyme in cholesterol biosynthesis, HMGCR, at Lys248. In addition, we revealed that TRC8 is the major E3 ubiquitin ligase for HMGCR ubiquitination in HEK293T cells, and the arsenite-induced diminution of HMGCR ubiquitination is abrogated with depletion of TRC8. In summary, we systematically characterized arsenite-induced perturbations in ubiquitinated proteome in human cells, and found that the arsenite-elicited diminution of HMGCR ubiquitination involves TRC8.