Piperine ameliorates psoriatic skin inflammation by inhibiting the phosphorylation of STAT3.

• Piperine inhibits M5-induced psoriatic dermatitis. • Piperine inhibits IMQ-induced psoriasis-like skin lesions. • Piperine inhibits STAT3 phosphorylation and activity. Psoriasis is a common chronic inflammatory skin disease that is easy to relapse and difficult to cure. Piperine is the main alkaloid extracted from black pepper, and its role in psoriasis has not been previously reported. We identified that piperine ameliorated M5-induced psoriatic skin lesions. Furthermore, piperine alleviated psoriasis pathological features including epidermal hyperplasia and inflammatory cell infiltration, decreased the expression of psoriasis-characteristic cytokines, chemokines and proteins in IMQ-induced psoriasiform dermatitis. Moreover, we determined that piperine inhibited the phosphorylation of STAT3 in M5- and IMQ-induced psoriasis-like skin lesions. Our data demonstrated that piperine ameliorated psoriatic skin inflammation by inhibiting the phosphorylation of STAT3. Therefore, piperine may be one potential compound candidate for psoriasis therapy, providing new strategies for clinical intervention. [ABSTRACT FROM AUTHOR]