Project description:As a group, fibroproliferative disorders of the lung, liver, kidney, heart, vasculature and integument are common, progressive and refractory to therapy. They can emerge following toxic insults, but are frequently idiopathic. Their enigmatic propensity to resist therapy and progress to organ failure has focused attention on the myofibroblast – the primary effector of the fibroproliferative response. A central unanswered question is whether these myofibroblasts have acquired a distinct pathological phenotype - or whether they are normal myofibroblasts with a pathological phenotype that depends upon residing in a sea of pro-fibrotic cytokines and an abnormal extracellular matrix. Using a systems approach to study this question in a prototype fibrotic disease, Idiopathic Pulmonary Fibrosis (IPF); here we show organized changes in the gene expression pathway of primary lung myofibroblasts that persist for up to 9 sub-cultivations in vitro. When comparing IPF and control myofibroblasts in a 3-dimensional type I collagen matrix, more genes differed at the level of ribosome recruitment than at the level of transcript abundance, indicating pathological translational control as a major characteristic of IPF myofibroblasts. To determine the effect of matrix state on translational control, myofibroblasts were permitted to contract the matrix. Ribosome recruitment in control myofibroblasts was relatively stable. In contrast, IPF cells manifested large alterations in the ribosome recruitment pattern. Pathological studies suggest an epithelial origin for IPF myofibroblasts through the epithelial to mesenchymal transition (EMT). In accord with this, we found systems-level indications for TGF?b -driven EMT as one source of IPF myofibroblasts. Keywords: cell type comparison Comparison of lung myofibroblasts from patients with Idiopatic Pulmonary Fibrosis (IPF, 6 donors) to control (6 donors) in contractile and non-contractile matrices using both total and polyribosomal RNA
Project description:Fibrotic disease is caused by persistently activated fibroblasts, known as myofibroblasts, that continuously deposit extracellular matrix and fail to de-activate after injury resolution. There are currently no treatments for fibrotic disease; our study addresses the mechanisms whereby myofibroblasts persist in fibrotic tissues such as diseased cardiac valves. We exploit photo-softening hydrogels as synthetic valve tissue mimics and valve fibroblasts as a model to study how stiffness controls pathological myofibroblast activation and their persistence. We show that persistent myofibroblasts have condensed chromatin structure with genome-wide alterations and that this is associated with stabilization of the actin cytoskeleton. Disconnecting the nucleus from the cytoskeleton prevents chromatin condensation and myofibroblast persistence. Notably, myofibroblasts in patients with aortic valve stenosis display a condensed chromatin structure compared to myofibroblasts in a healthy patient, similar to the difference observed between cultured persistent myofibroblasts and transient myofibroblasts. Collectively, our results reveal that nuclear mechanosensing leads to distinct chromatin signatures in persistent myofibroblasts and that this novel cellular mechanism is likely relevant to human fibrotic disease.
Project description:Hepatic stellate cells are the primary cell type responsible for development of fibrosis in chronic liver disease. We used directional RNA sequencing (RNA-seq) and chromatin immunoprecipitation and sequencing (ChIP-seq) to identify the lncRNAs expressed in human HSCs. We also identified the lncRNAs that change in expression with differentiation of nonfibrotic quiescent HSCs into fibrotic HSC myofibroblasts and those that are regulated by TGF-beta signaling. ChIP-seq was also performed to identify DNA regions occupied by H3K27ac to define super-enhancers in HSC myofibroblasts. This study identified lncRNAs expressed HSCs that may regulate fibrosis. Analysis of genome-wide lncRNA expression using RNA-seq and ChiP-seq in human HSCs under four different conditions
Project description:As a group, fibroproliferative disorders of the lung, liver, kidney, heart, vasculature and integument are common, progressive and refractory to therapy. They can emerge following toxic insults, but are frequently idiopathic. Their enigmatic propensity to resist therapy and progress to organ failure has focused attention on the myofibroblast – the primary effector of the fibroproliferative response. A central unanswered question is whether these myofibroblasts have acquired a distinct pathological phenotype - or whether they are normal myofibroblasts with a pathological phenotype that depends upon residing in a sea of pro-fibrotic cytokines and an abnormal extracellular matrix. Using a systems approach to study this question in a prototype fibrotic disease, Idiopathic Pulmonary Fibrosis (IPF); here we show organized changes in the gene expression pathway of primary lung myofibroblasts that persist for up to 9 sub-cultivations in vitro. When comparing IPF and control myofibroblasts in a 3-dimensional type I collagen matrix, more genes differed at the level of ribosome recruitment than at the level of transcript abundance, indicating pathological translational control as a major characteristic of IPF myofibroblasts. To determine the effect of matrix state on translational control, myofibroblasts were permitted to contract the matrix. Ribosome recruitment in control myofibroblasts was relatively stable. In contrast, IPF cells manifested large alterations in the ribosome recruitment pattern. Pathological studies suggest an epithelial origin for IPF myofibroblasts through the epithelial to mesenchymal transition (EMT). In accord with this, we found systems-level indications for TGF-beta -driven EMT as one source of IPF myofibroblasts. Keywords: cell type comparison
Project description:Here, we investigate the role of enhancers in myofibroblasts, a cell type that dominates the pathogenesis and progression of tissue fibrosis. We reveal that bromodomain and extra-terminal family members (BETs), an important group of epigenetic readers, are critical for super-enhancer-mediated pro-fibrotic gene expression in hepatic stellate cells (HSCs, lipid-containing liver-specific pericytes), upon activation during liver fibrogenesis give rise to myofibroblasts2-4. We observe significantly enriched localization of BETs to hundreds of super-enhancers associated with genes involved in multiple pro-fibrotic pathways. This unique loading pattern consequentially serves as a molecular mechanism by which BETs modulate pro-fibrotic gene expression in myofibroblasts. Strikingly, suppression of BET-enhancer interaction using small-molecule inhibitors such as JQ1 dramatically blocks activation of HSCs into myofibroblasts and significantly compromises the proliferation of activated HSCs. Identification of BRD2, BRD3, BRD4, PolII, PolIIs2p and PolIIs5p binding sites in human stellate LX2 cells that were treated with DMSO (0.1%) or JQ1 (500nM) for 16 hrs.
Project description:Gene expression profiling of immortalized human mesenchymal stem cells with hTERT/E6/E7 transfected MSCs. hTERT may change gene expression in MSCs. Goal was to determine the gene expressions of immortalized MSCs.