Calcipotriol increases intracellular cathelicidin LL-37 but not its extracellular form in IL-17/IL-22-stimulated human keratinocytes

Abstract

Cathelicidin peptide LL-37 can interact with self-DNA in psoriatic skin. Extracellular self-DNA/LL-37 complexes activate plasmacytoid dendritic cells. Cytosolic DNA has recently been identified as a danger signal that activates inflammasomes containing DNA sensor AIM2 and converting proIL-1β to IL-1β. LL-37 neutralizes cytosolic DNA in keratinocytes (KCs) and blocks inflammasome activation. Thus, LL-37 promotes psoriasis with extracellular DNA, but suppresses psoriasis with cytosolic DNA. Given that KCs are exposed to Th17-derived cytokines in psoriasis, it is reasonable to investigate the in vitro effects of calcipotriol on the production of LL-37 in KCs stimulated with IL-17 and IL-22.