Project 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. We quantified expression profile of 210 inflammatory-relating genes in the 67LR-downregulated cells treated with LPS or/and EGCG by microarray
Project description:This is a randomized, placebo controlled, multicentric trial to investigate the effect of diet supplementation with green tea extract containing 300mg epigallocatechin gallate (EGCG), the major polyphenol of green tea, on the recurrence of colon adenomas.
Project 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.
Project description:Epigallocatechin-3-gallate (EGCG) is the most plentiful polyphenol in green tea and has antiviral, antioxidant, anti-aging, anti-inflammatory, and neuroprotective effects . Studies have shown that EGCG can inhibit a diversity of biological processes of tumor progression, including cell proliferation, invasion, metastasis, and angiogenesis, and can also induce apoptosis and cell cycle arrest. In order to investigate the role of EGCG in multiple myeloma (MM), we carried out this study. We found that EGCG could inhibit myeloma cell activity and promote myeloma cell apoptosis. To further explore the mechanism of EGCG promoting apoptosis in myeloma cells, cells were treated with EGCG and subjected to RNA sequencing.
Project description:Mi(cro)RNAs are small non-coding RNAs of 18-25 nucleotides in length that modulate gene expression at the post-transcriptional level. These RNAs have been shown to be involved in a several biological processes, human diseases and metabolic disorders. Proanthocyanidins, which are the most abundant polyphenol class in the human diet, have positive heath effects on a variety of metabolic disorders such as inflammation, obesity, diabetes and insulin resistance. The present study aimed to evaluate whether proanthocyanidin-rich natural extracts modulate miRNA expression. Using microarray analysis and Q-PCR, we investigated miRNA expression in HepG2 cells treated with proanthocyanidins. Our results showed that when HepG2 cells were treated with grape seed proanthocyanidin extract (GSPE), cocoa proanthocyanidin extract (CPE) or pure epigallocatechin gallate isolated from green tea (EGCG), fifteen, six and five differentially expressed miRNAs, respectively, were identified out of 904 mRNAs. Specifically, miR-30b* was downregulated by the three treatments, and treatment with GSPE or CPE upregulated miR-1224-3p, miR-197 and miR-532-3p. Therefore, these results provide evidence of the capacity of dietary proanthocyanidins to influence microRNA expression, revealing a new mechanism of action of proanthocyanidins. microRNA profiling of Human hepatocellular liver carcinoma cell line (HepG2) comparing control untreated HepG2 cells with cells treated with grape seed proanthocyanidin extract (100 mg/L, 5h), cacao proanthocyanidin extract (100 mg/L, 5h) or epigallocatechin gallate (50 mg/L, 5h). Two biologival replicates were used for control and treated cells with one replicate per array.
Project description:Alzheimer’s disease (AD) is the most common form of adult-onset dementia with severe intellectual deterioration and is characterised by the accumulation of the amyloid-β (Aβ) peptides and the presence of hyperphosphorylated microtubule- associated protein, tau. (-)-Epigallocatechin-3-gallate (EGCG) – a polyphenolic catechin found in green tea leaves, not only acts as a proteasome inhibitor, it is also involved in neuroprotection.
Project description:Epigallocatechin gallate (EGCG), the major green tea polyphenol, has been a subject of global interest as a potential chemopreventive or chemotherapeutic supplement for breast cancer. While on one hand epidemiological studies suggest inverse correlation between green tea consumption and breast cancer risk, investigations using cell culture and animal models of breast carcinogenesis on the other hand have demonstrated antiproliferative, antitumor, anti-invasive and anti-metastatic properties of EGCG. Mechanism of how EGCG affects cell proliferation, apoptosis, migration and cell cycle by affecting the function of a wide range of molecular targets have also been studied. However, the question as to how EGCG impacts on estrogen responsive genes has not been addressed. This issue is of relevance to our notion of EGCG as a potential chemopreventive or chemotherapeutic agent against breast cancer, which is estrogen dependent in majority of the newly diagnosed cases. Here, using the estrogen receptor α (ERα) positive MCF-7 breast cancer cells as a model, we have examined the effect of EGCG on the estrogen regulated genes.
Project description:Alzheimer’s disease (AD) is the most common form of adult-onset dementia with severe intellectual deterioration and is characterised by the accumulation of the amyloid-β (Aβ) peptides and the presence of hyperphosphorylated microtubule- associated protein, tau. (-)-Epigallocatechin-3-gallate (EGCG) – a polyphenolic catechin found in green tea leaves, not only acts as a proteasome inhibitor, it is also involved in neuroprotection. A total of 7 RNA samples were analyzed. Cultured murine primary cortical neurons were treated with 1uM EGCG for 24h (n=3) in addition to the vehicle control (n=4).
Project description:Experimental studies have shown the chemopreventive properties of green tea extract (GTE) on colorectal cancer. And colorectal adenomas are precursors to colorectal cancers. The aim of this study is to determine the preventive effect of GTE supplements on metachronous colorectal adenomas by giving GTE tablets of which are equivalent of 9 cup-of-green tea per day (0.9 g/day GTE, 0.6 g/day Epigallocatechin gallate (EGCG).
Project description:Epigallocatechin gallate (EGCG), the major green tea polyphenol, has been a subject of global interest as a potential chemopreventive or chemotherapeutic supplement for breast cancer. While on one hand epidemiological studies suggest inverse correlation between green tea consumption and breast cancer risk, investigations using cell culture and animal models of breast carcinogenesis on the other hand have demonstrated antiproliferative, antitumor, anti-invasive and anti-metastatic properties of EGCG. Mechanism of how EGCG affects cell proliferation, apoptosis, migration and cell cycle by affecting the function of a wide range of molecular targets have also been studied. However, the question as to how EGCG impacts on estrogen responsive genes has not been addressed. This issue is of relevance to our notion of EGCG as a potential chemopreventive or chemotherapeutic agent against breast cancer, which is estrogen dependent in majority of the newly diagnosed cases. Here, using the estrogen receptor α (ERα) positive MCF-7 breast cancer cells as a model, we have examined the effect of EGCG on the estrogen regulated genes. MCF7 cells were treated with vehicle (Ethanol) or EGCG in the presence or absence of estrogen for 24hrs. Total RNA was extracted; Cy3 labeled cRNA was hybridized to Genotypic Technology designed Custom Human Whole Genome 8x60k Microarray (Agilent-027114). Median signal intensities were used for the analysis. After background subtraction (normexp) and normalization (quantile) differentially expressed genes were identified using linear models.