Dataset Information

The GARDpotency Assay for Potency-Associated Subclassification of Chemical Skin Sensitizers-Rationale, Method Development, and Ring Trial Results of Predictive Performance and Reproducibility.

ABSTRACT: Proactive identification and characterization of hazards attributable to chemicals are central aspects of risk assessments. Current legislations and trends in predictive toxicology advocate a transition from in vivo methods to nonanimal alternatives. For skin sensitization assessment, several OECD validated alternatives exist for hazard identification, but nonanimal methods capable of accurately characterizing the risks associated with sensitizing potency are still lacking. The GARD (Genomic Allergen Rapid Detection) platform utilizes exposure-induced gene expression profiles of a dendritic-like cell line in combination with machine learning to provide hazard classifications for different immunotoxicity endpoints. Recently, a novel genomic biomarker signature displaying promising potency-associated discrimination between weak and strong skin sensitizers was proposed. Here, we present the adaptation of the defined biomarker signature on a gene expression analysis platform suited for routine acquisition, confirm the validity of the proposed biomarkers, and define the GARDpotency assay for prediction of skin sensitizer potency. The performance of GARDpotency was validated in a blinded ring trial, in accordance with OECD guidance documents. The cumulative accuracy was estimated to 88.0% across 3 laboratories and 9 independent experiments. The within-laboratory reproducibility measures ranged between 62.5% and 88.9%, and the between-laboratory reproducibility was estimated to 61.1%. Currently, no direct or systematic cause for the observed inconsistencies between the laboratories has been identified. Further investigations into the sources of introduced variability will potentially allow for increased reproducibility. In conclusion, the in vitro GARDpotency assay constitutes a step forward for development of nonanimal alternatives for hazard characterization of skin sensitizers.

SUBMITTER: Gradin R

PROVIDER: S-EPMC7416325 | biostudies-literature | 2020 Aug

REPOSITORIES: biostudies-literature

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The GARDpotency Assay for Potency-Associated Subclassification of Chemical Skin Sensitizers-Rationale, Method Development, and Ring Trial Results of Predictive Performance and Reproducibility.

Gradin Robin R Johansson Angelica A Forreryd Andy A Aaltonen Emil E Jerre Anders A Larne Olivia O Mattson Ulrika U Johansson Henrik H

Toxicological sciences : an official journal of the Society of Toxicology 20200801 2

Proactive identification and characterization of hazards attributable to chemicals are central aspects of risk assessments. Current legislations and trends in predictive toxicology advocate a transition from in vivo methods to nonanimal alternatives. For skin sensitization assessment, several OECD validated alternatives exist for hazard identification, but nonanimal methods capable of accurately characterizing the risks associated with sensitizing potency are still lacking. The GARD (Genomic All ...[more]

PMID: 32421796

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Project description:Proactive identification of chemicals with skin sensitizing properties is a key toxicological endpoint within chemical safety assessment, as required by legislation for registration of chemicals. In order to meet demands of increased animal welfare and facilitate increased testing efficiency also in nonregulatory settings, considerable efforts have been made to develop nonanimal approaches to replace current animal testing. Genomic Allergen Rapid Detection (GARD™) is a state-of-the-art technology platform, the most advanced application of which is the assay for assessment of skin sensitizing chemicals, GARD™skin. The methodology is based on a dendritic cell (DC)-like cell line, thus mimicking the mechanistic events leading to initiation and modulation of downstream immunological responses. Induced transcriptional changes are measured following exposure to test chemicals, providing a detailed evaluation of cell activation. These changes are associated with the immunological decision-making role of DCs in vivo and include among other phenotypic modifications, up-regulation of co-stimulatory molecules, induction of cellular and oxidative stress pathways and xenobiotic responses, and provide a holistic readout of substance-induced DC activation. Here, results from an inter-laboratory ring trial of GARD™skin, conducted in compliance with OECD guidance documents and comprising a blinded chemical test set of 28 chemicals, are summarized. The assay was found to be transferable to naïve laboratories, with an inter-laboratory reproducibility of 92.0%. The within-laboratory reproducibility ranged between 82.1% and 88.9%, whereas the cumulative predictive accuracy across the 3 laboratories was 93.8%. It was concluded that GARD™skin is a robust and reliable method for the identification of skin sensitizing chemicals and suitable for stand-alone use or as a constituent of integrated testing. These data form the basis for the regulatory validation of GARD™skin.

Project description:BACKGROUND: Due to the recent European legislations posing a ban of animal tests for safety assessment within the cosmetic industry, development of in vitro alternatives for assessment of skin sensitization is highly prioritized. To date, proposed in vitro assays are mainly based on single biomarkers, which so far have not been able to classify and stratify chemicals into subgroups, related to risk or potency. METHODS: Recently, we presented the Genomic Allergen Rapid Detection (GARD) assay for assessment of chemical sensitizers. In this paper, we show how the genome wide readout of GARD can be expanded and used to identify differentially regulated pathways relating to individual chemical sensitizers. In this study, we investigated the mechanisms of action of a range of skin sensitizers through pathway identification, pathway classification and transcription factor analysis and related this to the reactive mechanisms and potency of the sensitizing agents. RESULTS: By transcriptional profiling of chemically stimulated MUTZ-3 cells, 33 canonical pathways intimately involved in sensitization to chemical substances were identified. The results showed that metabolic processes, cell cycling and oxidative stress responses are the key events activated during skin sensitization, and that these functions are engaged differently depending on the reactivity mechanisms of the sensitizing agent. Furthermore, the results indicate that the chemical reactivity groups seem to gradually engage more pathways and more molecules in each pathway with increasing sensitizing potency of the chemical used for stimulation. Also, a switch in gene regulation from up to down regulation, with increasing potency, was seen both in genes involved in metabolic functions and cell cycling. These observed pathway patterns were clearly reflected in the regulatory elements identified to drive these processes, where 33 regulatory elements have been proposed for further analysis. CONCLUSIONS: This study demonstrates that functional analysis of biomarkers identified from our genomics study of human MUTZ-3 cells can be used to assess sensitizing potency of chemicals in vitro, by the identification of key cellular events, such as metabolic and cell cycling pathways.

Dataset Information

The GARDpotency Assay for Potency-Associated Subclassification of Chemical Skin Sensitizers-Rationale, Method Development, and Ring Trial Results of Predictive Performance and Reproducibility.

Publications

The GARDpotency Assay for Potency-Associated Subclassification of Chemical Skin Sensitizers-Rationale, Method Development, and Ring Trial Results of Predictive Performance and Reproducibility.

Similar Datasets

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