Oral Administration of Taurodeoxycholate, A GPCR19 Agonist, Effectively Ameliorates Atopic Dermatitis in A Mouse Model

ABSTRACT Atopic dermatitis (AD) is the most prevalent chronic inflammatory skin disorder, characterised by intense pruritus and recurrent eczematous lesions. Recently, the US FDA has approved Janus kinase (JAK) inhibitors for oral treatment in AD patients. However, oral immunomodulatory agents have demonstrated adverse effects. In previous studies, we demonstrated the efficacy of topical taurodeoxycholate (TDCA), a G protein‐coupled receptor 19 (GPCR19) agonist, on AD. In this study, we further evaluated the efficacy of orally administered TDCA on MC903‐ and dinitrochlorobenzene (DNCB)‐induced AD mouse models. Oral administration of TDCA significantly ameliorated AD symptoms and reduced both epidermal and dermal thickness. Additionally, oral TDCA treatment inhibited the infiltration of myeloid and lymphoid cells into AD lesions. TDCA also suppressed the expression of thymic stromal lymphopoietin (TSLP), interleukin (IL)‐4, IL‐13, IL‐33, IL‐1β, tumour necrosis factor‐alpha (TNF‐α) and chemokine (C‐C motif) ligand 17 in the skin and blood. Given the previously demonstrated safety profiles of TDCA, oral TDCA may offer a beneficial and safer alternative for AD patients.