Potential inhibitory effects of the traditional herbal prescription Hyangso-san against skin inflammation via inhibition of chemokine production and inactivation of STAT1 in HaCaT keratinocytes.

Inflammatory skin disease are caused by multiple factors, including susceptibility genes, and immunologic and environmental factors, and are characterized by an increase in epidermal thickness and the infiltration of macrophages, keratinocytes, mast cells, eosinophils and other inflammatory cells. Keratinocytes may serve an important role in the pathogenesis of inflammatory skin diseases. The traditional herbal decoction Hyangso­san (HSS) has been used to treat symptoms of the common cold, including headache, pantalgia, fever and chills. However, to the best of our knowledge, there is no evidence regarding whether HSS has an effect on inflammatory skin diseases. The present study investigated the anti­skin inflammation activity of HSS using the HaCaT human keratinocyte cell line. The mRNA expression and production of inflammatory chemokines, including C­C motif chemokine ligand 22 (CCL22), CCL5, CCL17, and interleukin (IL)­8, was measured using reverse transcription polymerase chain reaction and ELISA analyses. Moreover, we evaluated the effect of HSS on signal transducer and activator of transcription 1 (STAT1) pathway in HaCaT cells. The cells were stimulated with tumor necrosis factor­α (TNF­α) and interferon­Î³ (IFN­Î³) to induce an inflammatory reaction. In the TNF­α­ and IFN­Î³­stimulated cells, the production and expression of inflammatory chemokines were observed, including CCL22, CCL5, CCL17 and IL­8. In addition, stimulation with TNF­α and IFN­Î³ increased the phosphorylation and nuclear translocation of STAT1 in HaCaT cells. By contrast, HSS extract treatment inhibited TNF­α­ and IFN­Î³­induced STAT1 activation. Results from the present study indicated that HSS exhibited inhibitory effects on TNF­α­ and IFN­Î³­mediated chemokine production and expression by targeting STAT1 in keratinocytes. Overall, the results indicated that HSS may be a potential candidate therapeutic drug for inflammatory skin diseases such as atopic dermatitis.