Testing Human Skin and Respiratory Sensitizers—What Is Good Enough?

Int. J. Mol. Sci. 2017, 18(2), 241; doi:10.3390/ijms18020241 Malmborg A., Borrebaeck C. A.K. Abstract Alternative methods for accurate in vitro assessment of skin and respiratory sensitizers are urgently needed. Sensitization is a complex biological process that cannot be evaluated accurately using single events or biomarkers, since the information content is too restricted in these measurements. […]

Int. J. Mol. Sci. 2017, 18(2), 241; doi:10.3390/ijms18020241

Malmborg A., Borrebaeck C. A.K.

Abstract

Alternative methods for accurate in vitro assessment of skin and respiratory sensitizers are urgently needed. Sensitization is a complex biological process that cannot be evaluated accurately using single events or biomarkers, since the information content is too restricted in these measurements. On the contrary, if the tremendous information content harbored in DNA/mRNA could be mined, most complex biological processes could be elucidated. Genomic technologies available today, including transcriptional profiling and next generation sequencing, have the power to decipher sensitization, when used in the right context. Thus, a genomic test platform has been developed, denoted the Genomic Allergen Rapid Detection (GARD) assay. Due to the high informational content of the GARD test, accurate predictions of both the skin and respiratory sensitizing capacity of chemicals, have been demonstrated. Based on a matured dendritic cell line, acting as a human-like reporter system, information about potency has also been acquired. Consequently, multiparametric diagnostic technologies are disruptive test principles that can change the way in which the next generation of alternative methods are designed.
Keywords:

genomics; skin sensitization; adverse outcome pathways; next generation in vitro tests

senzagen member of the board

Ian Kimber joins the board of SenzaGen AB

SenzaGen AB, a diagnostic spin-off company from Lund University, is proud to announce that Prof. Ian Kimber will join the Board of Directors. SenzaGen AB is a diagnostic company working to replace animal testing for sensitization predictions. Prof Ian Kimber is currently Professor of Toxicology and Associate Dean for Business Development in the Faculty of […]

SenzaGen AB, a diagnostic spin-off company from Lund University, is proud to announce that Prof. Ian Kimber will join the Board of Directors.

SenzaGen AB is a diagnostic company working to replace animal testing for sensitization predictions.

Prof Ian Kimber is currently Professor of Toxicology and Associate Dean for Business Development in the Faculty of Life Sciences at the University of Manchester. He has broad research interests at the interface between toxicology and immunology, with a particular focus on allergy and inflammation.  Professor Kimber holds, and has held, a variety of positions on national and international expert and scientific advisory committees. Currently these include the following:  Member UK Medicines and Healthcare products Regulatory Agency (MHRA) Committee for Safety of Devices, Programme Advisor Food Standards Agency Food Allergy and Intolerance Research Programme, and member MRC Translational Research Group. Professor Kimber was previously President of the British Toxicology Society (BTS) (2012-2014), and Chairman of the Board of the UK National Centre for the Replacement, Refinement and Reduction of Animals in Research (NC3Rs) (2008-2013).  

“I am delighted to be joining the Board of SenzaGen at such an exciting period of growth. Since our initial studies that led to the development and ultimate validation of the Local Lymph Node Assay I have maintained a keen interest in chemical allergy and in the development of novel approaches for improved hazard identification and risk assessment. In this respect harnessing fully the opportunities afforded by developments in the biomedical sciences is critical, and the work of SenzaGen in exploiting a genomic approach to pathway analysis and risk assessment is at the cutting edge of new developments”, says Prof Kimber.

Ian Kimber has published over 600 research papers, review articles and book chapters, and serves currently on the editorial boards of toxicology, immunology, dermatology and pathology journals.

“We are very happy to have Prof Kimber on board in SenzaGen”, since he is one of the forerunners in sensitization testing, says Prof Carl Borrebaeck, “his knowledge and interest in the field of allergy and replacement of animal testing with new technologies is very important to us. We value his participation in developing the next generation tests.”

 

Press release in pdf

Genomic allergen rapid detection in-house validation-a proof of concept.

Toxicol Sci. 2014 Jun;139(2):362-70. doi: 10.1093/toxsci/kfu046. Epub 2014 Mar 27. Johansson H., Rydnert F., Kuehnl J., Schepky A., Borrebaeck C.A.K., Lindstedt M. Abstract Chemical sensitization is an adverse immunologic response to chemical substances, inducing hypersensitivity in exposed individuals. Identifying chemical sensitizers is of great importance for chemical, pharmaceutical, and cosmetic industries, in order to prevent […]

Toxicol Sci. 2014 Jun;139(2):362-70. doi: 10.1093/toxsci/kfu046. Epub 2014 Mar 27.

Johansson H., Rydnert F., Kuehnl J., Schepky A., Borrebaeck C.A.K., Lindstedt M.

Abstract

Chemical sensitization is an adverse immunologic response to chemical substances, inducing hypersensitivity in exposed individuals. Identifying chemical sensitizers is of great importance for chemical, pharmaceutical, and cosmetic industries, in order to prevent the use of sensitizers in consumer products. Historically, chemical sensitizers have been assessed mainly by in vivo methods, however, recently enforced European legislations urge and promote the development of animal-free test methods able to predict chemical sensitizers. Recently, we presented a predictive biomarker signature in the myeloid cell line MUTZ-3, for assessment of skinsensitizers. The identified genomic biomarkers were found to be involved in immunologically relevant pathways, induced by recognition of foreign substances and regulating dendritic cell maturation and cytoprotective mechanisms. We have developed the usage of this biomarker signature into a novel in vitro assay for assessment of chemical sensitizers, called Genomic Allergen Rapid Detection (GARD). The assay is based on chemical stimulation of MUTZ-3 cultures, using the compounds to be assayed as stimulatory agents. The readout of the assay is a transcriptional quantification of the genomic predictors, collectively termed the GARD Prediction Signature (GPS), using a complete genome expression array. Compounds are predicted as either sensitizers or nonsensitizers by a Support Vector Machine model. In this report, we provide a proof of concept for the functionality of the GARD assay by describing the classification of 26 blinded and 11 nonblinded chemicals as sensitizers or nonsensitizers. Based on these classifications, the accuracy, sensitivity, and specificity of the assay were estimated to 89, 89, and 88%, respectively.

KEYWORDS:

GARD; allergic contact dermatitis; chemical sensitizers; in vitro assay; predictive assay; skin sensitization

Link to article on line

Evaluation of high throughput gene expression platforms using a genomic biomarker signature for prediction of skin sensitization.

BMC Genomics. 2014 May 16;15:379. doi: 10.1186/1471-2164-15-379. Forreryd A., Johansson H., Albrekt A.S., Lindstedt M Abstract BACKGROUND: Allergic contact dermatitis (ACD) develops upon exposure to certain chemical compounds termed skin sensitizers. To reduce the occurrence of skin sensitizers, chemicals are regularly screened for their capacity to induce sensitization. The recently developed Genomic Allergen Rapid Detection […]

BMC Genomics. 2014 May 16;15:379. doi: 10.1186/1471-2164-15-379.

Forreryd A., Johansson H., Albrekt A.S., Lindstedt M

Abstract

BACKGROUND:

Allergic contact dermatitis (ACD) develops upon exposure to certain chemical compounds termed skin sensitizers. To reduce the occurrence of skin sensitizers, chemicals are regularly screened for their capacity to induce sensitization. The recently developed Genomic Allergen Rapid Detection (GARD) assay is an in vitro alternative to animal testing for identification of skinsensitizers, classifying chemicals by evaluating transcriptional levels of a genomic biomarker signature. During assay development and biomarker identification, genome-wide expression analysis was applied using microarrays covering approximately 30,000 transcripts. However, the microarray platform suffers from drawbacks in terms of low sample throughput, high cost per sample and time consuming protocols and is a limiting factor for adaption of GARD into a routine assay for screening of potential sensitizers. With the purpose to simplify assay procedures, improve technical parameters and increase sample throughput, we assessed the performance of three high throughput gene expression platforms–nCounter®, BioMark HD™ and OpenArray®–and correlated their performance metrics against our previously generated microarray data. We measured the levels of 30 transcripts from the GARD biomarker signature across 48 samples. Detection sensitivity, reproducibility, correlations and overall structure of gene expression measurements were compared across platforms.

RESULTS:

Gene expression data from all of the evaluated platforms could be used to classify most of the sensitizers from non-sensitizers in the GARD assay. Results also showed high data quality and acceptable reproducibility for all platforms but only medium to poor correlations of expression measurements across platforms. In addition, evaluated platforms were superior to the microarray platform in terms of cost efficiency, simplicity of protocols and sample throughput.

CONCLUSIONS:

We evaluated the performance of three non-array based platforms using a limited set of transcripts from the GARD biomarker signature. We demonstrated that it was possible to achieve acceptable discriminatory power in terms of separation between sensitizers and non-sensitizers in the GARD assay while reducing assay costs, simplify assay procedures and increase sample throughput by using an alternative platform, providing a first step towards the goal to prepare GARD for formal validation and adaption of the assay for industrial screening of potential sensitizers.

Link to article on line