Prunus Yeddensis Inhibits the Inflammatory Chemokines, MDC and TARC, by Regulating the STAT1-Signaling Pathway in IFN-γ-stimulated HaCaT Human Keratinocytes

Atopic dermatitis (AD) is an inflammatory skin disease commonly characterized by infiltration of inflammatory cells into skin lesions. Keratinocytes produce many chemokines that are involved in the pathogenesis of skin disorders. In particular, macrophage-derived chemokine (MDC/CCL22) and thymus and activation-regulated chemokine (TARC/CCL17) are Th2-type cytokines. Serum MDC and TARC levels are increased in AD patients. In this study, we investigated the anti-inflammatory effect and mechanism of action of the active fraction from Prunus yedoensis bark. We evaluated their inhibitory effects on the AD-like inflammatory markers (MDC: and TARC) and JAK-STAT pathway (STAT1) in HaCaT keratinocytes. The EtOAc fraction of the crude extract (80% EtOH) and the E5 sub-fraction potently inhibited the induction of MDC and TARC mRNA and protein at 50 mu g/mL in HaCaT cells. In addition, the E5 sub-fraction inhibited the phosphorylation of STAT1 protein associated with IFN-gamma signaling transduction in a dose-dependent manner. Thus, P. yedoensis may have anti-atopic activity by suppressing the inflammatory chemokines (MDC and TARC).