The role of NFkB in (1-->3)-B-glucan (Zymosan A) induced TNF-alpha production.
Young-S; Ye-J; Frazer-DG; Shi-X; Castranova-V
Proceedings of the 24th Cotton and Other Organic Dusts Research Conference, January 7-8, 2000, San Antonio, TX, Wakelyn-PJ, Jacobs-RR, Rylander-R, eds., Memphis, TN: The National Cotton Council, 2000 Jan; :15
The signal transduction pathway in the inflammatory response caused by a fungal cell wall component (1-->3)-B-glucan is not well understood. The present study used zymosan A-induced tumor necrosis factor (TNF)-alpha production as a model to explore the signal transduction pathway for B-glucan stimulation in RAW264.7 cells. Zymosan A increased TNF-alpha production in RAW264.7 cells in a time and concentration dependent pattern with the optimal time and concentration occurring at 23 hr and 100 ug/mL zymosan A, respectively. A gel shift assay was used to examine the DNA-binding activity of NFkB in the zymosan A- treated cells. This NFkB activity was enhanced by this stimulant. NFkB activation was associated with TNF-alpha production, since the cells pre-treated with a known NFkB inhibitor (caffeic acid phenethyl ester) decreased both NFkB activation and TNF-alpha production. The dependence of TNF-alpha transcriptional initiation on kB sites was investigated using a luciferase reporter assay. Both wild type and kB-mutated type TNF-alpha promoters were utilized to study the dependence of TNF-alpha promoter on kB sites. The results demonstrated that the activation of TNF-alpha promoter was dependent on the activation of NFkB. A NFkB specific reporter was used in conjunction with TNF-alpha wild type reporter to evaluate the temporal relationship between the NFkB activation and induction of TNF-alpha reporter activity. The results showed that the peak of NFkB activation occurred at 5 hrs which proceeded the peak of TNF-alpha promoter activation (30 hrs). The above results suggest that activation of NFkB is one of the pathways involved in zymosan A-induced TNF-alpha production.
Fungi; Fungicides; Fungal-infections; Models; Stimulants; Cell-cultures
Abstract; Conference/Symposia Proceedings
Wakelyn-PJ; Jacobs-RR; Rylander-R
Proceedings of the 24th Cotton and Other Organic Dusts Research Conference