Comprehensive and comparative analysis of gene expression induced by LPA- and CP-609,550 in normal human epidermal keratinocytes (NHEKs)

We screened highly expressed G-protein coupled receptors (GPCRs) in normal human epidermal keratinocytes (NHEKs). We then tested the effect of ligands of selected GPCRs for their potency to induce the expression of FLG, a crucial skin barrier marker gene, in NHEKs. We used CP-609,550, a JAK inhibitor, as a positive control. As a result, we identified Oleoyl-L-α-lysophosphatidic acid (LPA) as a strong FLG inducer in NHEKs. In addition, we found that LPA induced NHEKs morphological changes characteristics of differentiated keratinocytes. Notably, although CP-609,550 also induced FLG expression in NHEKs, it didn't affect NHEKs cell morphology. We further conducted comprehensive and comparative microarray analysis of gene expression induced by LPA and CP-609,550 in NHEKs. We found that LPA treatment not only induced FLG expression but also expression of several genes related to keratinocytes differentiation, epidermis development and cornified envelope. This was not observed in the CP-609,550-treated cells. Gene expression induced by 10μM Oleoyl-L-α-lysophosphatidic acid or 1μM CP-609,550 in NHEKs were measured at 72h and compared to gene expression in the vehicle control-treated NHEKs. Three independent experiments were performed for each condition.