Atopic Dermatitis (AD) is a multifactorial disease. Activated keratinocytes release proinflammatory cytokines that induce Th2 lymphocytes to produce key AD inflammatory microenvironment. The endocannabinoid system (ECS), including cannabinoid receptors, their endogenous ligands and the metabolic enzymes of these ligands, has recently been implicated in the regulation of various skin process, including proliferation and immuno-tolerance of keratinocytes. Alterations of some components of ECS have been recently hypothesized in AD, but no studies have exhaustively investigated the role of all members of ECS. In this pilot study, we studied the expression of ECS components in AD in vitro model. HaCaT were cultured in DMEM with 10% FBS. HaCaT maturation was obtained by adding 1.8 mM CaCl2 every day for 7 days. On the last day, cells were treated with IL-4+IL13+INFγ at 10 ng/mL each for 24 hours to develop the AD model. The mRNA expression of following ECS genes were evaluated, by using TaqMan Real Time PCR Technology: CB1, CB2, GPR55, TRPV1, PPARα, PPARγ, PPARδ, NAPE-PLD, FAAH, DAGLα, DAGLβ, MAGL. Relative quantification was performed by the comparative ΔΔCt method. Regarding the ECS receptors, we observed a significant 2-fold increase of PPARα (p=0.02) in AD vs control keratinocytes; GPR55 and PPARδ resulted more elevated in diseased cells, although the differences were borderline for significativity (p=0.06 and p=0.07, respectively). A not significant increase was reported for CB1, PPARγ and TRPV1 transcripts (p=0.31, p=0.11 and p=0.22 respectively). With regard to ECS enzymes, AD showed not significant higher mRNA levels of FAAH and MAGL and a lower expression of NAPE-PLD (p=0.15, p=0.23, p=0.70, respectively). The expression of DAGLα (p=0.264) and DAGLβ (p=0.687) genes was similar between the two conditions. Our preliminary finding demonstrated the modulation of ECS pathway in the atopic dermatitis in vitro, with a marked increase of PPAR nuclear receptors.

ESDR401 - Endocannabinoid pathway in Atopic Dermatitis: results from an in vitro pilot study

The scientific meeting of the European Society for Dermatological Research (ESDR) is held yearly, usually in September. With an international attendance of more than 1000 skin scientists from around the globe, the four-day event includes short oral presentations from peer-reviewed abstracts, keynote lectures from international experts, sponsored symposia, satellite programs, educational events as well as an important focus on posters, networking and building collaborations amongst scientists. For more information about this year’s meeting visit our website.