The role or NF-kappaB in 1-->3-beta-glucan(zymosan)induced TNF-alpha production.
Young-S; Ye-J; Frazer-DG; Shi-X; Castranova-V
Cotton and Other Organic Dusts. Proceedings of the Twenty-fourth Cotton and Organic Dusts Research Conference, Beltwide Cotton Conferences, San Antonio, TX, January 7 - 8, 2000. Memphis, TN: National Cotton Council, 2000 Jan; 1:241-247
The signal transduction pathway of inflammatory response to 1-->3-beta-glucans, a fungal cell wall component, is not well understood. Tumor necrosis factor (TNF)-alpha is an important cytokine in inflammation. The present study used zymosan A (a source of 1-->3-beta-glucans)-induced TNF-alpha production as a model to explore the signal transduction pathway of 1-->3-beta-glucans. The results show that zymosan A induced TNF-alpha production by mouse macrophage RAW264.7 cells in a time- and concentration- dependent pattern. The optimal concentration of zymosan A was 100 micrograms/ml for TNF-alpha simulation. The TNF-alpha level reached a plateau around 12.5 hrs. in the cell culture medium. The mechanism of zymosan A-induced TNF-alpha production was investigated at the gene transcription level. The gel shift assay was used to examine the DNA-binding activity of NF-kappaB in the zymosan A-treated cells. The results showed that NF-kappaB activity was increased by zymosan A, and this activity was associated with TNF-alpha production. Aluciferase reporter controlled by the TNF-alpha promoter was utilized to examine promoter activity of the TNF-alpha gene in transiently transfected RAW264.7 cells. The results demonstrated that zymosan A could activate the gene promoter and the induced-promoter activity peaked and 24 hours after zymosan A stimulation. The promoter response depended on the NF-kappaB binding site as verified by using a NFkappaB inhibitor (caffeic acid phenethyl ester) and by mutation of the NF-kappaB binding site in the promoter. Combined together, these results suggest that activation of NF-kappaB is a very important pathway by which zymosan A induces TNF-alpha expression.
Fungi; Fungal-infections; Fungal-diseases; Genes; Cell-cultures
Wakelyn-PJ; Jacobs-RR; Rylander-R
Cotton and Other Organic Dusts. Proceedings of the Twenty-fourth Cotton and Organic Dusts Research Conference, Beltwide Cotton Conferences, San Antonio, TX, January 7 - 8, 2000