ABSTRACT: Gene expression profile of liver tissue in low-dose, repeated diethylnitrosamine (DEN)-treated rat treated with epigallocatechin gallate (EGCG)
Project description:Gene expression profiling was performed in each of hepatocyte fraction and non-parenchymal cell fraction enriched with activated hepatic stellate cells/myofibroblasts from cirrhotic rat livers induced by repeated, low-dose diethylnitrosamine (DEN) treatment.
Project description:Male rats received repeated low-dose diethylnitrosamine (DEN) to induce liver cirrhosis, and were treated with nizatidine to examine change of liver transcriptome and its association with liver cancer chemopreventive effect of nizatidine.
Project description:Background: Hepatocellular carcinoma (HCC) is increasing in incidence and treatment is often unsuccessful. Thus, prevention in high-risk patients with established cirrhosis has been proposed as an alternative strategy. It has been suggested that the increased inflammation and fibrogenesis observed during cirrhosis predisposes the liver to future malignant transformation to HCC through a “field effect”. A growing body of evidence indicates that the green tea polyphenol, (-)-epigallocatechin gallate (EGCG), can reduce inflammation and fibrogenesis during chronic liver injury. Here, we test the hypothesis that EGCG administered in the setting of cirrhosis can prevent future HCC development. Methods: A rat model of diethylnitrosamine (DEN)-induced cirrhosis was used to examine the efficacy of EGCG for inhibition of HCC formation in these cirrhotic livers. DEN (50 mg/kg) was administered weekly throughout the study while 0.02% EGCG was given in drinking water beginning at the onset of cirrhosis. At the end of the study, rats were sacrificed, livers were sectioned and stained to analyze disease progression and tumor nodules were counted. Liver function tests were performed to determine liver injury and overall liver function. Finally, genome-wide gene expression profiling on the surrounding, non-tumoral liver tissue was used to monitor the “field effect” in response to EGCG. Results: EGCG significantly (p < 0.01) prevented the development of HCC tumor nodules from on average 18.8 in vehicle controls to on average 9.1 in EGCG-treated animals. EGCG also reduced liver injury and improved liver function as assessed by serum chemistry tests. Finally, a gene expression signature predictive of poor survival and HCC development in human cirrhosis patients was reversed in response to EGCG. Conclusions: Our data are consistent with the growing body of evidence suggesting that EGCG has protective effects in liver disease. Further, our results suggest that EGCG is a potentially effective HCC prevention strategy that can be monitored using gene expression signatures.
Project description:Gene expression profile of hepatocellular carcinoma in low-dose, repeated diethylnitrosamine (DEN)-treated rat treated with erlotinib
Project description:We have identified Epigallocatechin Gallate (EGCG) as a potent modulator of microglia function. Our aim was to determine whether EGCG affects the transcriptome of microglia and identify genes and gene sets that may underly the effects of EGCG on microglia function.
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:We reported the molecular mechanisms of low combination doses of epigallocatechin-3-gallate and hydroxychavicol (EGCG+HC) in glioma cell lines 1321N1 and LN18. Using high throughput RNA sequencing, combined EGCG+HC exerted its anticancer effect by downregulating the axon guidance process and metabolic pathways, while simultaneously interfering with endoplasmic reticulum unfolded protein response pathway. Furthermore, EGCG+HC exerted its apoptotic effect through the alteration of mitochondrial genes such as MT-CO3 and MT-RNR2 in 1321N1 and LN18 cells respectively. EGCG+HC dynamically altered DYNLL1 alternative splicing expression in 1321N1 and DLD splicing expression in LN18 cell lines.
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: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.