Project description:Transcriptomic profiling; Determination of the transcriptomic similarity between Egfr fl/fl and Met fl/fl progenitor cells isolated from excised livers (n=3, each) Profiling of hepatic progenitor cells
Project description:Transcriptomic profiling; Determination of the transcriptomic similarity between Egfr fl/fl and Met fl/fl progenitor cells isolated from excised livers (n=3, each)
Project description:MET and EGFR receptor tyrosine kinases are crucial for liver regeneration and normal hepatocyte function. Recently we demonstrated that in mice, combined inhibition of these two signaling pathways abolished liver regeneration following hepatectomy, with subsequent hepatic failure and death at 15-18 days post-resection. Morbidity was associated with distinct and specific alterations in important downstream signaling pathways that led to a decrease in hepatocyte volume, reduced proliferation, and shutdown of many essential hepatocyte functions such as fatty acid synthesis, urea cycle, and mitochondrial functions. In the present study we explore the role of MET and EGFR signaling in resting mouse livers that are not subjected to hepatectomy. Mice with combined disruption of MET and EGFR signaling (Delta MET + EGFRi) were noticeably sick by 10 day and died at 12-14 days. Delta MET + EGFRi mice showed decreased liver to body weight ratios, increased apoptosis in non-parenchymal cells, impaired liver metabolic functions, and activation of distinct, downstream signaling pathways related to inflammation, cell death, and survival. Conclusion: The present study demonstrates that in addition to controlling the regenerative response, MET and EGFR synergistically control baseline liver homeostasis in normal mice in such a way that their combined disruption leads to liver failure and death. We used microarrays to detail the global programme of gene expression in Delta MET + EGFRi mice liver vs control mice liver
Project description:HGF has been reported to have both positive and negative effects on carcinogenesis. Here we show that the loss of c-Met signaling in hepatocytes enhanced rather than suppressed the early stages of chemical hepatocarcinogenesis. c-Met conditional knockout mice (c-metfl/fl, AlbCre+/-; MetLivKO) treated with N-nitrosodiethylamine (DEN) developed significantly more and bigger tumors and with a shorter latency as compared with control (wt/wt, AlbCre+/-; Cre-Ctrl) mice. Accelerated tumor development was associated with increased rate of cell proliferation and prolonged activation of epidermal growth factor receptor (EGFR) signaling. MetLivKO livers treated with DEN also displayed elevated lipid peroxidation, decreased ratio of reduced glutathione (GSH) to oxidized glutathione (GSSG), and upregulation of superoxide dismutase 1 (Sod1) and heat shock protein 70 (Hsp70), all consistent with increased oxidative stress. Likewise, gene expression profiling performed at 3 and 5 months after DEN treatment revealed upregulation of genes associated with cell proliferation and stress responses in c-Met mutant livers. The negative effects of c-Met-deficiency were reversed by chronic oral administration of anti-oxidant N-acetylcysteine (NAC). NAC blocked the EGFR activation and reduced the DEN-initiated hepatocarcinogenesis to the levels of Cre-Ctrl mice. These results argue that intact HGF/c-Met signaling is essential for maintaining normal redox homeostasis in the liver and has tumor suppressor effect(s) during the early stages of DEN-induced hepatocarcinogenesis. Keywords: compound treatment design
Project description:Purpose: The goal of this study was to determine biological consequences during liver regeneration following partial hepatectomy in mice by next-generation sequencing. A particular interest was to compare mice with either a floxed b-PDGFR allele to mice that harbored a deletion of b-PDGFR in hepatic stellate cells (HSCs), by crossing b-PDGFR fl/fl mice with transgenic GFAP-Cre mice. Methods: b-PDGFR fl/fl mice or mice with a HSC-specific deletion of b-PDGFR underwent either sham operation or 70% partial hepatectomy. Following 72 hours, livers were collected and total RNA was extracted using tizol, followed by a purification using Quiagen spin columns including an on-column DNAse digestion step. Conclusion: Our study represents a detailed analysis of hepatic transcriptome, with biologic replicates, generated by RNA-seq technology of livers following sham operation or partial hepatectomy in b-PDGFR fl/fl mice or b-PDGFRfl/fl/GRAP-Cre mice. Whole liver mRNA profiles of sham operated livers or livers collected 72hours after partial hepatectomy of beta-PDGFR fl/fl and beta-PDGFR fl/fl/GFAP-Cre (creating a hepatic stellate cell-specific deletion of b-PDGFR) mice were generated by deep sequencing, in duplicate, using Illumina HiSeq2000.
Project description:To identify HGF/Met regulated genes, we performed expression microarray analysis after inducible activation of Met receptor in primary cultures of hepatocytes established from wild-type control (Alb-Cre +/-) and Met conditional knockout mice (Alb-Cre +/-; Met Fl/Fl). Keywords: time series design
Project description:HGF has been reported to have both positive and negative effects on carcinogenesis. Here we show that the loss of c-Met signaling in hepatocytes enhanced rather than suppressed the early stages of chemical hepatocarcinogenesis. c-Met conditional knockout mice (c-metfl/fl, AlbCre+/-; MetLivKO) treated with N-nitrosodiethylamine (DEN) developed significantly more and bigger tumors and with a shorter latency as compared with control (wt/wt, AlbCre+/-; Cre-Ctrl) mice. Accelerated tumor development was associated with increased rate of cell proliferation and prolonged activation of epidermal growth factor receptor (EGFR) signaling. MetLivKO livers treated with DEN also displayed elevated lipid peroxidation, decreased ratio of reduced glutathione (GSH) to oxidized glutathione (GSSG), and upregulation of superoxide dismutase 1 (Sod1) and heat shock protein 70 (Hsp70), all consistent with increased oxidative stress. Likewise, gene expression profiling performed at 3 and 5 months after DEN treatment revealed upregulation of genes associated with cell proliferation and stress responses in c-Met mutant livers. The negative effects of c-Met-deficiency were reversed by chronic oral administration of anti-oxidant N-acetylcysteine (NAC). NAC blocked the EGFR activation and reduced the DEN-initiated hepatocarcinogenesis to the levels of Cre-Ctrl mice. These results argue that intact HGF/c-Met signaling is essential for maintaining normal redox homeostasis in the liver and has tumor suppressor effect(s) during the early stages of DEN-induced hepatocarcinogenesis. Keywords: compound treatment design To address a role for c-Met in liver carcinogenesis, we employed a hepatocyte specific c-Met conditional knockout mouse model generated in our laboratory. Mice received a single intraperitoneal injection of 10 µg/g body weight of N-nitrosodiethylamine (DEN) (Sigma-Aldrich, Inc., St. Louis, MO, USA) at 14 days of age. Livers were examined at 3 and 5 months after DEN injection. Expression profiling was conducted on five animals from each genotype per time point. Total RNA pooled from five wild-type B6/129 strain mouse livers was used as universal hybridization reference. All experiments were performed in duplicates following a dye-swapping design. Arrays were scanned with a GenePix 4000A scanner (Axon Instruments Ltd., Burlingame, CA) in a way to achieve optimal signal intensity at both channels with less than 1% saturated spots. After excluding the invalid features, all arrays were normalized to the 50th percentile of the median signal intensity using the mAdb data analysis suite (http://nciarray.nci.nih.gov/). Unsupervised cluster analysis was performed with the Cluster and TreeView programs (http://rana.lbl.gov/EisenSoftware.htm). The BRB ArrayTools V3.3.0 software package (Biometric Research Branch, National Cancer Institute; http://linus.nci.nih.gov/BRB-ArrayTools.html) was used for the supervised comparison. Differentially expressed genes were selected using a univariate 2-sample t-test (P<0.001) with a random variance model (15). Functional classification of the significant genes was based on the Gene Ontology (GO) annotations (www.geneontology.org).
Project description:To identify gene expression changes associated with receptor tyrosine kinase (RTK) activation, we performed RNA-Seq analysis of murine pro-B BAF3 cells over-expressing the oncogenic form of EGFR (EGFR-L858R-T790M), FGFR (TEL-FGFR1 fusion), MET (TPR-MET fusion) or RET (CCDC6-RET fusion) genes. We reported the RTK-driven transcriptional reprogramming of metabolic genes.
Project description:Background: HGF/c-Met signaling plays a pivotal role in hepatocyte survival and tissue remodeling during liver regeneration. Treatment with HGF has been shown to accelerate resolution of fibrotic liver lesions in experimental animal models. To formally address the importance of c-Met signaling in hepatocytes in the context of chronic liver injury, we have used hepatocyte-specific Metfl/fl;Alb-Cre+/- conditional knockout mice (KO) and a model of liver fibrosis. Methods: CCl4 was administrated biweekly over a period of 4 weeks (injury phase), and the animals were followed over the next 4 weeks (healing phase). Macroscopic and microscopic changes during the injury and healing phases were monitored by IHC. Deposition of ECM was assessed by Sirius red staining and hydroxiproline content. Activation of hepatic stellate cells (HSC) was estimated by a-SMA using WB and IHC. Expression levels of the selected key fibrotic molecules were evaluated by RT-qPCR and WB. Time-dependent global transcriptomic changes from whole livers and isolated hepatocytes were examined using gene expression microarrays. Results: Loss of HGF/c-Met signaling in hepatocytes altered the hepatic microenvironment and dramatically aggravated hepatic fibrogenesis. Increased liver damage was associated with decreased hepatocyte proliferation, progressive accumulation of HSCs, and delayed fibrinolysis causing increased collagen deposit. Dystrophic calcification of necrotic areas impaired phagocytosis, resulting in sustained inflammatory and fibrogenic signaling further augmenting severity of fibrogenesis. Global gene-expression analysis demonstrated upregulation of key fibrogenic molecules, such as Tgf-â and Pdgf-â, paralleled by a decreased expression of genes important for cell cycle, stress response and regeneration, which could be attributed to the c-Met deficiency in hepatocytes. Additionally, key chemotactic and inflammatory cytokines, including Ccl2, SDF1/Cxcr4 and Spp1, were upregulated in Metfl/fl;Alb-Cre+/- hepatocytes. However, the major pro-fibrotic signaling originated from the non-parenchymal cell compartments, as revealed by cell type-specific gene expression signatures. Conclusion: These results indicate that lack of c-Met signaling in hepatocytes disrupts the balance between extracellular matrix production and degradation and establish a protective role for c-Met against adverse microenvironment leading to the development of fibrotic liver disease. In the present study, we reported a detailed and comprehensive dynamic characterization of the cellular and molecular alterations involved in fibrosis in the liver of c-Met transgenic mice. Liver samples from female animals were collected at various time-points after fibrosis induction using CCL4 ranging from 0 weeks to 3 weeks. Tissue samples were divided into two parts; one was fixed in 10% formalin for histological evaluation and the other was used for RNA analysis.
Project description:TGF-b1 induces hepatic progenitor cells experience an epithelial-mesenchymal transition, and EGF could reverse this process via mesenchymal-epithelial transition. Yet, the mechanism underline these EMT and MET processes are not clear. The aim of this study is to reveal the genes with significant difference during these EMT and MET process in hepatic progenitor cells.