Project name: Mus musculus

Description: Epigallocatechin-3-gallate (EGCG), a major active polyphenol of green tea, has been shown to downregulate inflammatory responses in macrophages; however, the underlying mechanism has not been understood. Recently, we identified the 67-kDa laminin receptor (67LR) as a cell-surface EGCG receptor that mediates the anti-cancer action of EGCG at physiologically relevant concentrations (0.1-1 mM). Here we show the molecular basis for the downregulation of TLR4 signal transduction by EGCG at 1 mM in macrophages. Anti-67LR antibody treatment or RNAi-mediated silencing of 67LR resulted in abrogation of the inhibitory action of EGCG on LPS-induced activation of downstream signaling pathways and target gene expressions. Additionally, we found that EGCG reduced the TLR4 expression through 67LR. Interestingly, EGCG induced a rapid upregulation of Tollip protein, a negative regulator of TLR-signaling, and this EGCG action was prevented by 67LR silencing or anti-67LR antibody treatment. RNAi-mediated silencing of Tollip impaired the TLR4 signaling inhibitory activity of EGCG. Taken together, these findings demonstrate that 67LR plays a critical role in mediating anti-inflammatory action of a physiologically relevant EGCG and Tollip expression could be modulated through 67LR. These results provide a new insight into the understanding of negative regulatory mechanisms for TLR4 signaling pathway and consequent inflammatory responses which are implicated in the development and progression of many chronic diseases.Overall design: We quantified expression profile of 210 inflammatory-relating genes in the 67LR-downregulated cells treated with LPS or/and EGCG by microarray

Data type: Transcriptome or Gene expression

Sample scope: Multiisolate

Relevance: ModelOrganism

Release date: 2010-04-20

Last updated: 2010-04-13