Il‐1 Alpha‐induced Expression of Icam‐1 on Cultured Hyperproliferative Keratinocytes: Suppression by Antipsoriatic Dimethyl‐fumarate

BACKGROUND: In the psoriatic plaque both IL-1 dysregulation and ICAM-1 expression on keratinocytes have been previously described. Furthermore systemic administration of fumarates has been reported to be effective in psoriasis. We, therefore, studied the effect of dimethyl-fumarate ester (DMF) on the putative IL-1-induced ICAM-1 expression. METHODS: Hyperproliferative human keratinocytes (HaCaT cell line) were incubated in 10 to 100 U/mL IL-1 alpha for 24 h with and without preincubation with 0.4-12.0 microM DMF: Expression of ICAM-1 was measured by a special ELISA-APAAP technique. RESULTS: The exposure to IL-1 led to a significant dose-dependent induction of ICAM-1 expression of from 124 +/- 17 to 194 +/- 22% (control 100 +/- 12%), while proliferation remained unaltered. Pretreatment with > or = 4 microM DMF resulted in a distinct suppression of ICAM-1 expression and a slight decrease in proliferation. CONCLUSIONS: The present results show that ICAM-1 expression on hyperproliferative keratinocytes may be triggered by IL-1 alpha and serve as a molecular target for antipsoriatic DMF.