Researchers from the University of Aveiro, the University of Coimbra and the University Hospital of Coimbra have developed a dendritic cell-based test for skin sensitizers that can serve as an alternative to animal testing.
The study developed an in vitro predictive test based on the analysis and integration of gene expression and intracellular signaling profiles of chemical-exposed, skin-derived dendritic cells. The findings were published in the American Chemical Society's journal Chemical Research in Toxicology.
Cells were treated with four known sensitizers and two non-sensitizers, and the effects on the expression of 20 candidate genes and the activation of MAPK, PI3K/Akt and NF-κB signaling pathways were analyzed by real-time reverse transcription polymerase chain reaction and Western blotting, respectively. Genes Trxr1, Hmox1, Nqo1, and Cxcl10 and the p38 MAPK and JNK signaling pathways were identified as good predictor variables and used to construct a dichotomous classifier. For validation of the model, 12 new chemicals were then analyzed in a blind assay, and from these, 11 were correctly classified.
Considering the total of 18 compounds tested here, 17 were correctly classified, representing a concordance of 94%, with a sensitivity of 92% (12 of 13 sensitizers identified) and a specificity of 100% (5 of 5 non-sensitizers identified).
Additionally, the researchers tested the ability of their model to discriminate sensitizers from non-allergenic but immunogenic compounds such as lipopolysaccharide (LPS). LPS was correctly classified as a non-sensitizer.
Overall, their results indicate that the analysis of proposed gene and signaling pathway signatures in a mouse fetal skin-derived dendritic cell line represents a valuable model to be integrated in a future in vitro test platform. As cosmetic products are often tested for sensitization, this testing method could have great implication in the personal care market.
The authors acknowledge funding from Fundação para a Ciência e a Tecnologia (FCT), Fundo Comunitário Europeu (FEDER) and Programa Operacional Factores de Competitividade (COMPETE).