Project description:To further development of our gene expression approach to biodosimetry, we have employed whole genome microarray expression profiling as a discovery platform to to study the genes that change in the progress of human liver fibrosis, so as to provide a basis for the clinical treatment of liver fibrosis.
Project description:Persistent liver injury triggers a fibrogenic program that causes pathologic remodelling of the hepatic microenvironment (i.e., liver fibrosis) and portal hypertension. The dynamics of gene regulation during liver disease progression and regression remain understudied. Here, we generated hepatic transcriptome profiles in two well-established liver disease models at peak fibrosis and during spontaneous regression after the removal of the inducing agents. We linked the dynamics of key liver disease readouts, such as portal pressure, collagen proportionate area, and transaminase serum levels, to most differentially expressed genes, enabling the identification of transcriptomic signatures of progressive vs. regressive liver fibrosis and portal hypertension. These candidate biomarkers (e.g., Scube1, Tcf4, Src, Hmga1, Trem2, Mafk, Mmp7) were also validated in RNA-seq datasets of patients with cirrhosis and portal hypertension. Finally, deconvolution analysis identified major cell types and suggested an association of macrophage and portal hepatocyte signatures with portal hypertension and fibrosis area in both models.
Project description:End stage liver disease due to Hepatitis C Virus (HCV) infection is a major health concern worldwide. Liver fibrosis following chronic HCV infection plays a pivotal role in loss of liver function and end stage liver disease. However the dynamics and molecular events that lead to fibrosis in HCV infection are poorly defined. Therefore, we determined the influence of HCV infection in altering the miRNA expression levels which can modulate immune responses to HCV leading to fibrosis. Analysis of the miRNA expression profiles of HCV infected liver biopsies revealed that 45 miRNAs were differentially expressed in the HCV infected liver when compared to normal livers. In silico target prediction of these differentially expressed miRNAs indicated that their targets include chemokine/cytokine signaling, cell cycle genes and extracellular matrix protein gene expression. Gene expression profiling using whole genome microarray demonstrated that 1320 genes were differentially expressed in chronic HCV liver when compared to normal. These genes could be functionally grouped into those involved in cell cycle regulation, cytokines and chemokines expression, cell adhesion, intracellular signaling and enzymes. Further pathway analysis using GeneGo software identified cell adhesion, cytoskeleton remodeling, cytokine signaling and metabolic pathways as the major pathways activated in chronic HCV. Combinatorial target prediction analysis of miRNA expression along with gene expression analysis indicated that differentially expressed microRNAs in HCV significantly impact transforming growth factor beta (TGF-?) signaling pathway, cell adhesion (integrin expression), chemokine signaling, Notch signaling and cell-cycle( Cyclin D,K) regulation. Overall these results demonstrate that chronic HCV infection induces specific miRNA signatures that will modulate genes involved in the cytoskeletal remodeling and cytokine signaling that can promote the development of fibrosis following HCV infection. Liver biopsies from chronic HCV patients and control liver biopsies from normal subjects (donor liver prior to transplantation) were used to analyze the miRNA and gene expression profile. Patients with HBV and/or HIV were excluded from the study. This Series represents the mRNA gene expression profiling data only.
Project description:The lack of adequate human in vitro models that recapitulate the cellular composition and response of the human liver to injury hampers the development of anti-fibrotic drugs. The goal of this study was to develop a human spheroid culture model to study liver fibrosis by using induced pluripotent stem cell (iPSC)-derived liver cells. iPSCs were independently differentiated towards hepatoblasts (iHepatoblasts), hepatic stellate cells (iHSCs), endothelial cells (iECs) and macrophages (iMΦ), before assembly into free floating spheroids by culturing cells in 96-well U-bottom plates and orbital shaking for up to 21 days to allow further maturation. Through transcriptome analysis, we show further maturation of iECs and iMΦ, the differentiation of the iHepatoblasts towards hepatocyte-like cells (iHeps) and the inactivation of the iHSCs by the end of the 3D culture. Moreover, these cultures display a similar expression of cell-specific marker genes (CYP3A4, PDGFRβ, CD31 and CD68) and sensitivity to hepatoxicity as spheroids made using freshly isolated primary human liver cells. Furthermore, we show the functionality of the iHeps and the iHSCs by mimicking liver fibrosis through iHep-induced iHSC activation, using acetaminophen. In conclusion, we have established a reproducible human iPSC-derived liver culture model that can be used to mimic fibrosis in vitro as a replacement of primary human liver derived 3D models. The model can be used to investigate pathways involved in fibrosis development and to identify new targets for chronic liver disease therapy
Project description:To determine gene signatures associated with advanced liver fibrosis, we undertook RNA-sequencing of liver biopsies from patients presenting with different aetiologies (HCV or FLD) and fibrosis stages (n=69 patients). This dataset is part of the TransQST collection.