Assuntos
Nanocápsulas/administração & dosagem , Administração Cutânea , Animais , Portadores de Fármacos , Genisteína/administração & dosagem , Cobaias , Nanocápsulas/química , Oxazinas/química , Poliglactina 910/química , Pele/efeitos dos fármacos , Pele/patologia , Eletricidade Estática , Raios UltravioletaRESUMO
In our search for NF-kappaB inhibitors from natural resources, we have previously identified two structurally related dilignans, manassantin A and B as specific inhibitors of NF-kappaB activation from Saururus chinensis. However, their molecular mechanism of action remains unclear. We here demonstrate that manassantins A and B are potent inhibitors of NF-kappaB activation by the suppression of transciptional activity of RelA/p65 subunit of NF-kappaB. These compounds significantly inhibited the induced expression of NF-kappaB reporter gene by LPS or TNF-alpha in a dose-dependent manner. However, these compounds did not prevent the DNA-binding activity of NF-kappaB assessed by electrophoretic mobility shift assay as well as the induced-degradation of IkappaB-alpha protein by LPS or TNF-alpha. Further analysis revealed that manassantins A and B dose-dependently suppressed not only the induced NF-kappaB activation by overexpression of RelA/p65, but also transactivation activity of RelA/p65. Furthermore, treatment of cells with these compounds prevented the TNF-alpha-induced expression of anti-apoptotic NF-kappaB target genes Bfl-1/A1, a prosurvival Bcl-2 homologue, and resulted in sensitizing HT-1080 cells to TNF-alpha-induced cell death. Similarly, these compounds also suppressed the LPS-induced inducible nitric oxide synthase expression and nitric oxide production. Taken together, manassantins A and B could be valuable candidate for the intervention of NF-kappaB-dependent pathological condition such as inflammation and cancer.
Assuntos
Furanos/farmacologia , Expressão Gênica/efeitos dos fármacos , NF-kappa B/genética , Saururaceae/química , Ativação Transcricional/efeitos dos fármacos , Animais , Apoptose , DNA/efeitos dos fármacos , DNA/metabolismo , Interações Medicamentosas , Furanos/isolamento & purificação , Humanos , Proteínas I-kappa B/metabolismo , Lignanas , Lipopolissacarídeos/farmacologia , Camundongos , Antígenos de Histocompatibilidade Menor , Inibidor de NF-kappaB alfa , NF-kappa B/antagonistas & inibidores , NF-kappa B/metabolismo , Óxido Nítrico/metabolismo , Óxido Nítrico Sintase/biossíntese , Óxido Nítrico Sintase/genética , Óxido Nítrico Sintase Tipo II , Proteínas Proto-Oncogênicas c-bcl-2/biossíntese , Proteínas Proto-Oncogênicas c-bcl-2/genética , Fator de Transcrição RelA , Células Tumorais Cultivadas , Fator de Necrose Tumoral alfa/farmacologiaRESUMO
Sauchinone, a known lignan, was isolated from the root of Saururus chinensis as an active principle responsible for inhibiting the production of NO in LPS-stimulated RAW264.7 cells by activity-guided fractionation. Sauchinone dose-dependently inhibited not only the production of NO, but also the expression of iNOS mRNA and protein in LPS-stimulated RAW 264.7 cells. Furthermore, sauchinone prevented LPS-induced NF-kappaB activation, which is known to play a critical role in iNOS expression, assessed by a reporter assay under the control of NF-kappaB. However, an electrophoretic mobility shift assay (EMSA) demonstrated that sauchinone did not suppress the DNA-binding activity of NF-kappaB or the degradation of IkappaB-alpha induced by LPS. Further analysis revealed that transactivation activity of RelA subunit of NF-kappaB was dose-dependently suppressed in the presence of sauchinone. Taken together, our results suggested that sauchinone could inhibit production of NO in LPS-stimulated RAW264.7 cells through the suppression of NF-kappaB by inhibiting transactivation activity of RelA subunit.
