Triptolide-induced Transrepression of IL-8 NF-kappaB in Lung Epithelial Cells / 결핵
Tuberculosis and Respiratory Diseases
; : 52-66, 2001.
Article
em Ko
| WPRIM
| ID: wpr-29923
Biblioteca responsável:
WPRO
ABSTRACT
BACKGROUND: NF-κB is the most important transcriptional factor in Il-8 gene expression. Triptolide is a new compound that recently has been shown to inhibit NF-κB activation. The purpose of this study is to investigate how triptolide inhibits NF-κB-dependent IL-8 gene transcription in lung epithelial cells and to pilot the potential for the clinical application of triptolide in inflammatory lung diseases. METHODS: A549 cells were used and triptolide was provided from Pharmagenesis Company (Palo Alto, CA). In order to examine NF-κB-dependent IL-8 transcriptional activity, we established stable A549 IL-8-NF-κB-luc. cells and performed luciferase assays. IL-8 gene expression was measured by RT-PCR and ELISA. A Western blot was done for the study of IκBα degradation and as electromobility shift assay was done to analyze NF-κB DNA binding. p65 specific transactivation was analyzed by a cotransfection study using a Gal4-p65 fusion protein expression system. To investigate the involvement of transcriptional coactivators, we perfomed a transfection study with CBP and SRC-1 expression vectors. RESULTS: We observed that triptolide significantly suppresses NF-κB-dependent IL-8 transcriptional activity induced by IL-1β and PMA. RT-PCR showed that triptolide represses both IL-1β- and pMA-induced IL-8 mRNA expression and ELISA confirmed this triptolide-mediated IL-8 suppression at the protein level. However, triptolide did not affect IκBα degradation and NF-κB DNA binding. In a p65-specific transactivation study, triptolide significantly suppressed Gal4-p65TA1 and Gal4-p65TA2 activity suggesting that triptolide inhibits NF-κB activation by inhibiting p65 transactivation. However, this triptolide-mediated inhibition of p65 transactivation was not rescued by the overexpression of CBP or SRC-1, thereby excluding the role of transcriptional coactivators. CONCLUSIONS: Triptolide is a new compound that inhibits NF-κB-dependent IL-8 transcriptional activation by inhibiting p65 transactivation, but not by an IκBα-dependent mechanism. This suggests that triptolide may have a therapeutic potential for inflammatory lung diseases.
Palavras-chave
Texto completo:
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Base de dados:
WPRIM
Assunto principal:
DNA
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RNA Mensageiro
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Ensaio de Imunoadsorção Enzimática
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Transfecção
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Expressão Gênica
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Ativação Transcricional
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Western Blotting
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Interleucina-8
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NF-kappa B
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Células Epiteliais
Idioma:
Ko
Revista:
Tuberculosis and Respiratory Diseases
Ano de publicação:
2001
Tipo de documento:
Article