Inositol-C2-PAF down-regulates components of the antigen presentation machinery in a 2D-model of epidermal inflammation.

In cutaneous inflammatory diseases, such as psoriasis, atopic dermatitis and allergic contact dermatitis, skin-infiltrating T lymphocytes and dendritic cells modulate keratinocyte function via the secretion of pro-inflammatory cytokines. Keratinocytes then produce mediators that recruit and activate immune cells and amplify the inflammatory response. These pathophysiological tissue changes are caused by altered gene expression and the proliferation and maturation of dermal and epidermal cells. We recently demonstrated that the glycosidated phospholipid Ino-C2-PAF down-regulates a plethora of gene products associated with innate and acquired immune responses and inflammation in the HaCaT keratinocyte cell line. To further evaluate the influence of Ino-C2-PAF we established an in vitro 2D-model of epidermal inflammation. The induction of inflammation and the impact of Ino-C2-PAF were assessed in this system using a genome-wide microarray analysis. In addition, the expression of selected genes was validated using qRT-PCR and flow cytometry. Treatment of the keratinocytes with a mix of proinflammatory cytokines resulted in transcriptional effects on a variety of genes involved in cutaneous inflammation and immunity, while additional treatment with Ino-C2-PAF counteracted the induction of many of these genes. Remarkably, Ino-C2-PAF suppressed the expression of a group of targets that are implicated in antigen processing and presentation, including MHC molecules. Thus, it is conceivable that Ino-C2-PAF possess therapeutic potential for inflammatory skin disorders, such as psoriasis and allergic contact dermatitis.