Project description:To understand the fibrotic response in the CCl4 induced liver fibrosis model, we performed RNA-seq of liver samples from mice treated with oil or CCl4.
Project description:To investigate the differences in microRNA expression profiles between fibrotic and normal livers, we performed microRNA microarrays for total RNA extracts isolated from mouse livers treated with carbontetrachloride (CCl4) or corn-oil for 10 weeks (n=3/group). MicroRNAs were considered to have significant differences in expression level when the expression difference showed more than two-fold change between the experimental and control groups at p<0.05. We found that 12 miRNAs were differentially expressed in CCl4-induced fibrotic liver. To induce chronic liver fibrosis, seven-week-old mice received 0.6 ml/kg body weight of carbon-tetrachloride (CCl4) dissolved in corn-oil by intraperitoneal (i.p.) injection, twice a week for 10 weeks (n=3). As a control, same number of mice was injected with equal volume of corn-oil for 10 weeks.
Project description:Gene-expression profiles of liver tissue of cabon tetrachloride (CCl4)-treated and control mice were obtained before and after organotypic ex vivo tissue culture. keywords: liver tissue, mouse, gene-expression microarray, Illumina, ex vivo tissue culture
Project description:Liver fibrosis was found to be existed in all kinds of chronic liver diseases. Many studies suggested that DNA methylation was related with the pathogenesis of liver fibrosis. The aim of this study was to quantitatively detect DNA methylation changes in the whole genome in fibrotic liver tissues. Carbon tetrachloride (CCl4) was used to induce male mice liver fibrosis by intraperitoneal injection for 4 weeks. A genome-wide methylome analysis was performed using 850K BeadChips assays. The methylation status of 27 CpG dinucleotides located in 3 genes was detected by pyrosequencing to confirm chips data accuracy, and their mRNA expressions were examined by RT-qPCR methods. A total of 130,068 differentially methylated sites (DMS, 58,474 hypermethylated and 71,594 hypomethylated) between fibrotic liver tissues and control mice liver tissues were identified by the 850k BeadChips array. They distribute in each chromosome. Recognition of apoptotic cell, Notch and p38MAPK et al activities were significantly enriched in the Gene Ontology (GO) analyses. Cholesterol metabolism, bile secretion and more biosynthesis and metabolism pathway were enriched in KEGG pathway analyses. Many classical pathways of fibrogenesis and liver activity, as well as more biosynthetic and metabolic pathways, were found to be related to methylation changes. Our result facilitates future research for clinical application.
Project description:Abstract from Knabel et al. PLoS One (2015): Fibrosis refers to the accumulation of excess extracellular matrix (ECM) components and represents a key feature of many chronic inflammatory diseases. Unfortunately, no currently available treatments specifically target this important pathogenic mechanism. MicroRNAs (miRNAs) are short, non-coding RNAs that post-transcriptionally repress target gene expression and the development of miRNA-based therapeutics is being actively pursued for a diverse array of diseases. Because a single miRNA can target multiple genes, often within the same pathway, variations in the level of individual miRNAs can potently influence disease phenotypes. Members of the miR-29 family, which include mir29a, miR-29b and miR-29c, are strong inhibitors of ECM synthesis and fibrosis-associated decreases in miR-29 have been reported in multiple organs. We observed downregulation of miR-29a/b/c in fibrotic livers of carbon tetrachloride (CCl4) treated mice as well as in isolated human hepatocytes exposed to the pro-fibrotic cytokine TGF-β. Importantly, we demonstrate that a single systemic injection of a miR-29a expressing adeno-associated virus (AAV) can prevent and even reverse histologic and biochemical evidence of fibrosis despite continued exposure to CCl4. The observed therapeutic benefits were associated with AAV transduction of hepatocytes but not hepatic stellate cells, which are the main ECM producing cells in fibroproliferative liver diseases. Our data therefore demonstrate that delivery of mir-29 to the hepatic parenchyma using a clinically relevant gene delivery platform protects injured livers against fibrosis and, given the consistent fibrosis-associated downregulation of miR-29, suggests AAV-miR-29 based therapies may be effective in treating a variety of fibroproliferative disorders. The Taqman MicroRNA Array (Taqman Array Rodent MicroRNA A Cards v2.0, ABI) was run, using manufacturer's protocols, on 3 groups of mice with varying amounts fibrotic injury. The groups include carbon tetrachloride intraperitinially injected bi-weekly for 1, 4, and 8 weeks with n=4, 3, and 2 respectively for each group. The RNA was isolated from whole liver using the MiRvana miRNA Isolation Kit (Ambion) according to manufacturer's protocols. The fold_change.txt contains the following data columns; ID_Ref: mmu-miR being quantified not-treated (FC): Fold Change compared to not-treated group using Geometric mean normalization 1 week (FC): Fold Change compared to not-treated group using Geometric mean normalization 4 weeks (FC): Fold Change compared to not-treated group using Geometric mean normalization 8 weeks (FC): Fold Change compared to not-treated group using Geometric mean normalization
Project description:Liver fibrosis is a multifactorial trait that develops in response to chronic liver injury. Our aim was to characterize the genetic architecture of carbon tetrachloride (CCl4)-induced liver fibrosis using the Hybrid Mouse Diversity Panel (HMDP), a panel of over 100 genetically distinct mouse strains optimized for genome wide association studies and systems genetics. Chronic liver injury was induced by CCl4 injections twice weekly for six weeks. 437 mice received CCl4 and 256 received vehicle, after which animals were sacrificed for liver histology and gene expression. Using automated digital image analysis, we quantified fibrosis as the collagen proportionate area % (CPA%) of the whole section, excluding normal collagen. We discovered broad variation in fibrosis among the HMDP strains, demonstrating a significant genetic influence on this trait, with an estimated heritability (H2) of 44%. Genome-wide association analyses revealed significant and suggestive loci underlying susceptibility to fibrosis, some of which overlapped with loci identified in mouse crosses and human population studies. Liver global gene expression was assessed by RNA sequencing, and gene set enrichment analyses identified the underlying pathways, of which stellate cell involvement was prominent. We also performed expression quantitative trait locus analyses to identify strong causal candidate genes. Our results provide a rich resource for the design of experiments to understand mechanisms underlying fibrosis and for rational strain selection when testing anti-fibrotic drugs.
Project description:We conditionally deleted Yap/Taz from hepatocytes prior to induction of acute injury by injection of liver toxin carbon tetrachloride (CCl4).
Project description:Abstract from Knabel et al. PLoS One (2015): Fibrosis refers to the accumulation of excess extracellular matrix (ECM) components and represents a key feature of many chronic inflammatory diseases. Unfortunately, no currently available treatments specifically target this important pathogenic mechanism. MicroRNAs (miRNAs) are short, non-coding RNAs that post-transcriptionally repress target gene expression and the development of miRNA-based therapeutics is being actively pursued for a diverse array of diseases. Because a single miRNA can target multiple genes, often within the same pathway, variations in the level of individual miRNAs can potently influence disease phenotypes. Members of the miR-29 family, which include mir29a, miR-29b and miR-29c, are strong inhibitors of ECM synthesis and fibrosis-associated decreases in miR-29 have been reported in multiple organs. We observed downregulation of miR-29a/b/c in fibrotic livers of carbon tetrachloride (CCl4) treated mice as well as in isolated human hepatocytes exposed to the pro-fibrotic cytokine TGF-β. Importantly, we demonstrate that a single systemic injection of a miR-29a expressing adeno-associated virus (AAV) can prevent and even reverse histologic and biochemical evidence of fibrosis despite continued exposure to CCl4. The observed therapeutic benefits were associated with AAV transduction of hepatocytes but not hepatic stellate cells, which are the main ECM producing cells in fibroproliferative liver diseases. Our data therefore demonstrate that delivery of mir-29 to the hepatic parenchyma using a clinically relevant gene delivery platform protects injured livers against fibrosis and, given the consistent fibrosis-associated downregulation of miR-29, suggests AAV-miR-29 based therapies may be effective in treating a variety of fibroproliferative disorders.
Project description:Preclinical biomarkers useful for identification of idiosyncratic drugs have not been identified. It is hypothesized that patterns of transcript expression for the hepatotoxicants, including classical and idiosyncratic hepatotoxicants, are similar and the patterns differ from those of non-hepatotoxicants. This experiment is part of the biomarkers study, and focus on two clasical hepatotoxicants: Acetaminophen and Carbon tetrachloride. We have employed whole genome microarray expression profiling to identify liver gene expression changes induced by hepatotoxicants. For the same animal, urinary microRNA profiling were analyzed. APAP and CCl4 both significantly increased the urinary levels of 44 and 28 miRNAs, respectively. In addition, 10 of the increased miRNAs were in common between APAP and CCl4. Computational analysis was used to predict target genes of the 10 shared hepatotoxicant-induced miRNAs. From the same animals, liver gene expression profiling was performed using whole genome microarrays. Eight putative target genes were found to be significantly altered in the liver of APAP and CCl4 treated animals. Acetaminophen induced liver gene expression changes in rats (Six to seven week-old male Sprague-Dawley rats, provided by the US Food and Drug Administration National Center for Toxicological Research (NCTR) breeding colonies, were used for the study.) were measured at 6 hours, 24 hours, 3 days and 7 days after exposure to doses of 0, 100 and 1250 mg/kg. Carbon tetrachloride induced liver gene expression changes in rats were measured at 6 hours, 24 hours and 3 days after exposure to doses of 0, 50 and 2000 mg/kg. Each group has at least 4 animals, total of 96 samples.