Effect of isoliquiritigenin for the treatment of atopic dermatitis-like skin lesions in mice

Atopic dermatitis (AD) is a common chronic inflammatory skin disease characterized with high heterogeneity. Recent studies have suggested that it is driven by both terminal keratinocyte differentiation defects and type 2 immune responses. The mainstay steroid topical therapy has severe side effect and new treatment is in demand. Isoliquiritigenin (ISLG) is a small phenolic bioactive molecule from licorice that has shown multiple pharmacological effects against cancer, inflammatory disorder, and cardiovascular diseases. ISLG was evaluated in AD-like lesion model induced by the repetitive application of 2,4-dinitrochlorobenzene (DNCB) in BALB/c mice. Overall symptom score, serological and molecular changes of the skin lesions were evaluated. ISLG could ameliorate the overall manifestation of AD-like symptoms including scratching behavior incidence and skin lesion severity. At blood level, ISLG significantly suppressed the DNCB-induced IgE and Th2 cytokines up-regulation. At skin lesion site, ISLG also inhibited DNCB-induced pro-inflammatory cytokines like TNF-alpha, IL-6 as well as IL-4 expressions. In a human monocyte model THP-1, ISLG suppressed the up-regulation of CD86 and CD54 and abolished the DNCB-induced p38-alpha and ERK activation, suggesting a molecular mechanism for ISLG therapy. This study indicated that ISLG could be a potential therapeutic agent for the treatment of AD.