Human Transcriptomic Integrated Approach for Testing and Assessment Oral Reference Dose for Steatosis
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PROVIDER: PRJNA557466 | ENA |
REPOSITORIES: ENA
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Project description:Integrated Approaches to Testing and Assessment (IATA) are emerging as a means to strategically assess and test chemicals for toxicity, using existing information, and helping to identify potential data gaps. Adverse Outcome Pathways (AOPs) have recently been shown to be a good starting point for IATA development. Our interest in IATAs and AOP Networks (AOPNs) focuses on developing efficient testing and risk assessment strategies for new materials, new chemical entities, and setting environmental cleanup goals. We combine the maths logic of causality, specifically the notion of sufficiency to infer an adverse outcome, with AOPNs to develop Minimally Sufficient Sets of Key Events (MinSSKEs). These MinSSKEs represent a set of key events (can just be one key event) that taken together allow assessors to predict if an adverse outcome is likely or not. For our case study we use the military explosive trinitrotoluene (TNT). TNT is a relatively data rich chemical where the US Environmental Protection Agency has set a reference dose of 0.0005mg/kg-day, based on a point of departure for liver toxicity in dogs of 0.5mg/kg-day (a lowest observed adverse effect level; LOAEL) with uncertainty of 1,000X. Our IATA measures gene expression for genes in involved in our AOPN for energy metabolism, steatosis and oxidative stress in human induced pluripotent stem cells differentiated to hepatocytes exposed to TNT. We used a Bayesian statistical approach to identify differentially expressed genes, and a nonlinear data-driven dose-response modeling approach (Good Risk Assessment Values for Environmental Exposures; GRAVEE) to estimate points of departure for reference dose estimation. We obtained an RfD of 0.12mg/kg-day, with a 90% credible interval spanning from 0.02-0.19mg/kg-day using our IATA approach. Our RfD is based on a POD of 1.22mg/kg-day with a 90% credible interval spanning from 0.24-1.94mg/kg-day, and uncertainty of 10X after applying the IRIS uncertainty factors. Our PODs are highly comparable, with a difference of only 0.72mg/kg-day (or 2.44x). Our RfDs differ by 240x, owing to the fact that we have only a 10x uncertainty factor for human variability, whereas the IRIS assessment uses 1000x uncertainty for 10x animal-to-human extrapolation, 10x LOAEL-to-NOAEL extrapolation, and 10x for subchronic-to-chronic extrapolation. In this case study, our IATA resulted in a highly similar POD compared to the IRIS assessment, and an overall decrease in the uncertainty factors that needed to be applied. Our IATA approach worked well in this instance, and demonstrated several advantages by focusing on using a human-relevant in vitro model, data-driven POD modeling, and a net decrease in the overall risk assessment uncertainty factors, while maintaining the uncertainty associated with the data.
2022-07-02 | GSE135117 | GEO
Project description:N-acyl amino acid methyl esters (NAMEs), which are structurally similar to the signalling compounds N-acyl homoserine lactones (AHLs), have been identified in culture extracts of Roseovarius tolerans EL-164. However, previous studies have shown that NAMEs do not participate in AHL-mediated signalling and thus their ecological role remains unclear. To enable dose-dependent bioactivity-testing of NAMEs, we have established a quantification method for NAMEs. The concentrations determined for the major NAMEs produced by EL 164, C16:1- and C17:1-NAME, ranged between 0.7-5.7 mg L-1 and 5.3-86.4 µg L-1, respectively. We observed opposing production patterns for NAMEs and AHLs, with a continuously increasing NAME production during exponential growth and an accumulation in the stationary phase. We further conducted a spike-in experiment, using the previously determined metabolite concentrations. By comparing the transcriptomes of pre- and post-NAME or AHL spikes, we identified distinct impacts on gene expression patterns. Different genetic neighbourhoods were significantly up- or downregulated in NAME and AHL-spiked cultures. Yet no synergetic effect was observed. These findings exemplify the broad application range of dose-dependent testing and highlight the different biological activities of NAMEs and AHLs.
2024-10-28 | GSE270994 | GEO
Project description:We demonstrate how a multidisciplinary approach encompassing cellular reprogramming, transcriptomics, proteomics, metabolomics, modeling, network reconstruction and data management can be employed to unveil the mechanisms underlying the progression of steatosis. Proteomics revealed reduced AKT/mTOR signaling in fibroblasts derived from steatosis patients and further establishes that the insulin-resistant phenotype is present not only in insulin-metabolizing central organs, e.g. the liver, but is also manifested in skin fibroblasts. Transcriptome data enabled the generation of a regulatory network based on the transcription factor SREBF1, linked to a metabolic network of glycerolipid and fatty acid biosynthesis including the downstream transcriptional targets of SREBF1 which include LIPIN1 (LPIN) and low density lipoprotein receptor (LDLR). Glutathione metabolism was among the pathways enriched in steatosis patients in comparison to healthy controls. By using a model of the glutathione pathway we predict a significant increase in the flux through glutathione synthesis as both gamma-glutamylcysteine synthetase and glutathione synthetase have an increased flux. The transcriptomes of dermal fibroblasts derived from two patients with steatosis (60 yr, male BMI 45.7 (H0008) and 33 yr, female, BMI 51.3 (H0007)) and control fibroblasts (19 yr, female, BMI 21, (H0002)) were analyzed. Total RNA obtained from dermal fibroblasts derived from two patients with steatosis (60 yr, male BMI 45.7 (H0008) and 33 yr, female, BMI 51.3 (H0007)) and control fibroblasts (19 yr, female, BMI 21, (H0002)).
2013-12-31 | E-GEOD-37689 | biostudies-arrayexpress
Project description:Testing the effect of specific macronutrient combinations on mouse metabolism in vivo, we determined that diets pairing starch as carbohydrate with oleate as fat (42%:42% kcal) induced significant white adipose tissue pathology and hepatic steatosis compared to other isocaloric combinations.
2017-09-01 | GSE93800 | GEO
Project description:Reference testing - FVST, DTU, ENGAGE (E.coli, 2014-2015)
| PRJEB14641 | ENA
Project description:CPEB4 prevents hepatic steatosis
| PRJNA322835 | ENA