Identification of potential biomarkers for predicting acute dermal irritation by proteomic analysis

In vitro alternative tests aiming at replacing the traditional animal test for predicting the irritant potential of chemicals have been developed, but the assessment parameters or endpoints are still not sufficient for analysis. To discover novel endpoints for skin irritation responses, a proteomics approach was used to analyze the protein expression in human keratinocytes exposed to sodium lauryl sulfate in the present study. Among the 20 identified proteins with altered expression, small heat shock protein 27 (HSP27) and superoxide dismutase [Cu-Zn] were down-regulated while cofilin-1 was up-regulated significantly in response to the chemical challenge. Keratinocytes were exposed to acid and basic chemicals for further validation of the proteins. HSP27 displayed the most significant alteration both in mRNA and protein levels, accompanied by nuclear translocation. The irritation also induced an increased production of interleukin-1α in keratinocytes. These findings suggest that these proteins may be combinational biomarkers or additional endpoints for skin hazard assessment. Further investigation into the protein alterations would be helpful for the mechanistic understanding of skin irritation.