926 The role of HTR2A on langerhans cells in skin inflammation

Drugs altering serotonin levels have been reported to influence skin inflammation. Serotonin 2A receptor (HTR2A) is hypothesized play a key role in mediating inflammation as it widely-expressed on many immune cells and HTR2A partial agonist could attenuate imiquimod (IMQ)-induced psoriasiform murine model. Furthermore, analysis of data from GEO database has found mRNA expression be lower psoriatic cases compared control. We psoriasis genes were modulated human samples treated with agonist. In IMQ model, we exacerbated HTR2A-/- (KO) mice wild type (WT) ear epidermal thickness, population pro-inflammatory IL-23 IL-17 significantly increased. Using chimeric bone marrow transplant, KO hematopoietic stem (HSC) experienced more than WT HSCs. used FlowSOM algorithm, visualized via UMAP Langerhans (LC) the causing By treating LC depleted agonist, validated exacerbation will further verify conditional mice. IL23 secretion by LCs was increased determined ELISA γδ T IL17 IL22 when cocultured LCs. Phospholipase C (PLC) downregulated gene PLC antagonist functions. Immunofluorescence staining reanalysis single cell RNA sequencing pathways also reduced lesioned Overall, our demonstrated exacerbates pathway.