RESUMO
BACKGROUND: Mite antigen, extract from Dermatophagoides farinae in house dust, is a well-known causative agent of atopy or allergic diseases, which involves many inflammatory cytokines/chemokines expression. Heme oxygenase 1 (HO1) has recently emerged as an important cytoprotective enzyme against oxidative stress and inflammatory responses in many cell types. OBJECTIVE: The aim of this study was to investigate the possible mechanism by which wogonin, a natural product isolated from Scutellaria baicalensis, inhibited the mite antigen-induced chemokine expression in human keratinocytes, HaCaT cells. METHODS: The level of chemokine expression was measured by reverse transcription-polymerase chain reaction (RT-PCR) and signaling study was performed by Western blot analysis. RESULTS: The mite antigen-induced thymus- and activation-regulated chemokine (TARC/CCL17) expression in a dose-dependent manner via extracellular signal-regulated kinase (ERK) activation. However, it did not affect the expression of other chemokines including macrophage-derived chemokine (MDC/CCL22), RANTES, and IL-8. Interestingly, wogonin significantly suppressed the mite antigen-induced TARC expression via the induction of HO1. This suppression was completely restored by HO1 siRNA, suggesting a direct role of HO1 for the suppressive effect. Furthermore, exogenous CO, but not other end products of HO1 activity, also suppressed the mite antigen-induced TARC expression. CONCLUSION: Wogonin induces HO1 expression, which in turn HO1 and/or CO suppresses TARC expression induced by mite antigen in human HaCaT cells.
Assuntos
Quimiocinas CC/genética , Dermatite Atópica/tratamento farmacológico , Flavanonas/farmacologia , Heme Oxigenase-1/genética , Queratinócitos/efeitos dos fármacos , Queratinócitos/imunologia , Animais , Antígenos de Dermatophagoides/imunologia , Antígenos de Dermatophagoides/farmacologia , Linhagem Celular Transformada , Quimiocina CCL17 , Dermatite Atópica/imunologia , Dermatophagoides farinae , Medicamentos de Ervas Chinesas/química , Medicamentos de Ervas Chinesas/farmacologia , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Flavanonas/química , Expressão Gênica/efeitos dos fármacos , Expressão Gênica/imunologia , Heme Oxigenase-1/metabolismo , Humanos , Técnicas In Vitro , Queratinócitos/citologia , Fosforilação/efeitos dos fármacos , Scutellaria baicalensisRESUMO
Recently, it has been reported that curcumin, which is known as a potent antioxidant, acts as a non- stressful and non-cytotoxic inducer of the cytoprotective heme oxygenase (HO)-1. In this study, naturally occurring curcuminoids, such as pure curcumin, demethoxycurcumin (DMC) and bis-demethoxycurcumin (BDMC), were compared for their potential ability to modulate HO-1 expression and cytoprotective activity in human endothelial cells. All three curcuminoids could induce HO-1 expression and HO activity with differential levels. The rank order of HO activity was curcumin, DMC and BDMC. In comparison with endothelial protection against H2O2-induced cellular injury, cytoprotective capacity was found to be highest with curcumin, followed by DMC and BDMC. Interestingly, cytoprotective effects afforded by curcuminoids were considerably associated with their abilities to enhance HO activity. Considering that the main difference among the three curcuminoids is the number of methoxy groups (none for BDMC, one for DMC, and two for curcumin), the presence of methoxy groups in the ortho position on the aromatic ring was suggested to be essential to enhance HO-1 expression and cytoprotection in human endothelial cells. Our results may be useful in designing more efficacious HO-1 inducers which could be considered as promising pharmacological agents in the development of therapeutic approaches for the prevention or treatment of endothelial diseases caused by oxidative damages.
