Sulforaphane suppresses TARC/CCL17 and MDC/CCL22 expression through heme oxygenase-1 and NF-κB in human keratinocytes.

Sulforaphane (4-methylsulfinylbutyl isothiocyanate, SFN) from broccoli has been used a chemopreventive photochemical as detoxification of xenobiotics and anti-inflammatory, however, there is no studies for Th2 chemokine expression through heme oxygenase-1 and NF-κB in keratinocytes. Atopic dermatitis is a chronically relapsing pruritic inflammatory skin disease. SFN is demonstrated to have anti-inflammatory and anti-oxidant effects. This study aimed to define whether and how SFN regulates Th2-related chemokine production in human HaCaT keratinocytes. The level of chemokine expression was measured by reverse transcription polymerase chain reaction (RT-PCR) and signaling study was performed by Western blot analysis. Chemokine production was determined by enzyme-linked immunosorbent assay. Pretreatment with SFN suppressed interferon-γ (IFN-γ) and tumor necrosis factor (TNF)-α- induced thymus- and activation-regulated chemokine (TARC/CCL17) and macrophage-derived chemokine (MDC/CCL22) production in HaCaT keratinocytes. SFN inhibited IFN-γ and TNF-α-induced NF-κB activation as well as STAT1 activation. Interestingly, pretreatment with SFN result in significantly suppressed IFN-γ and TNF-α-induced TARC/CCL17 and MDC/CCL22 production through the induction of HO-1. This suppression was completely abolished by HO-1 siRNA. Furthermore, Carbon monoxide, but not other end products of HO-1 activity, also suppressed IFN-γ and TNF-α-induced TARC/CCL17 and MDC/CCL22 production. These results demonstrate that SFN has an inhibitory role in IFN-γ and TNF-α-induced production of TARC/CCL17 and MDC/CCL22 in human HaCaT cells by inhibition of NF-κB activation and induction of HO-1.