Anti-psoriatic properties of paeoniflorin: suppression of the NF-kappaB pathway and Keratin 17

BACKGROUND Psoriasis is a common inflammatory skin disease characterized by hyperproliferation of epidermal keratinocytes, however, there is still no curative therapy for psoriasis. Paeoniflorin (PF), a Chinese herbal medicine, has shown anti-inflammatory effects. OBJECTIVES We aimed to illustrate the effect and associated mechanism of PF on keratinocyte proliferation using the IMQ-induced psoriasis mouse model. MATERIALS AND METHODS The anti-psoriatic effect of PF in vivo and in vitro was assessed by western blot, RT-PCR, immunofluorescence, cell counting kit-8 and haematoxylin/eosin staining. RESULTS In vivo, epidermal thickness, dermal infiltrated lymphocytes and the level of several antimicrobial peptides, pro-inflammatory cytokines, and K17 were significantly reduced in mice with topical application of PF. In vitro, PF inhibited the proliferation of HaCaT cells in a dose-dependent manner, down-regulated K17 expression, and suppressed NF-kappaB activation. CONCLUSION Our findings indicate that PF may inhibit the proliferation of keratinocytes by targeting K17, suggesting that PF might be a potential target in the treatment of psoriasis.