Project description:Background: Asthma is the most common chronic lung disease in children and young adults worldwide. Airway remodelling (including increased fibroblasts and myofibroblasts in airway walls due to chronic inflammation) differentiates asthmatic from non-asthmatic airways. The increase in airway fibroblasts and myofibroblasts occurs via epithelial to mesenchymal transition (EMT) where epithelial cells lose their tight junctions and are transdifferentiated to mesenchymal cells, with further increases in myofibroblasts occurring via fibroblast-myofibroblast transition (FMT). Transforming growth factor (TGF)-β is the central EMT- and FMT-inducing cytokine. In this study, we have used next generation sequencing to delineate the changes in the fibroblast transcriptome induced by TGF-β treatment in both the short term and after differentiation into myofibroblasts, to gain an understanding of the contribution of TGF-b induced transdifferentiation to the asthmatic phenotype. The data obtained from RNAseq analysis was confirmed by quantitative PCR (qPCR). Results: As expected, we found that genes coding for intermediates in the TGF-β signalling pathways (SMADs) were differentially expressed after treatment, and genes involved in cytoskeletal pathways (FN1, LAMA, ITGB1) were differentially expressed in myofibroblasts compared to fibroblasts. Importantly, genes that were previously shown to be changed in asthmatic lungs (ADAMTS1, DSP, TIMPs, MMPs) were differentially expressed in myofibroblasts, strongly suggesting that TGF-β mediated differentiation of fibroblasts to myofibroblasts may underlie important changes in the asthmatic airway. We also identified new signalling pathways (AKT, PTEN) that are changed in myofibroblasts compared to fibroblasts. Conclusion: We have found a significant number of genes that are altered after differentiation of fibroblasts into myofibroblasts by TGF-β treatment, many of which were expected or predicted. However, we also identified novel genes and pathways that were affected after treatment of fibroblasts with TGF-β, which suggests additional pathways that that are activated during the transition between fibroblasts and myofibroblasts, and may contribute to the asthma phenotype.
Project description:Background: Differentiation of fibroblasts into myofibroblasts is necessary for wound healing, but excessive myofibroblast presence and persistence can result in scarring. Treatment for scarring is limited largely due to a lack of comprehensive understanding of how fibroblasts and myofibroblasts differ at the transcript level. The purpose of the study was to comprehensively characterize transcriptional profiles of injured fibroblasts relative to normal fibroblasts, utilizing fibroblasts from the vocal fold as a model for other areas of the body. Results: we identified differentially expressed genes between groups of normal fibroblasts, scarred fibroblasts, and fibroblasts treated with transforming growth factor-beta 1 (TGF-β1), which represented an induced-scar phenotype. Principal component analysis revealed clustering of normal fibroblasts separate from the clustering of fibroblasts treated with TGF-β1; scarred fibroblasts were more similar to normal fibroblasts than fibroblasts treated with TGF-β1. Enrichment analyses revealed pathways related to cell signaling, receptor-ligand activity, and regulation of cell functions in scarred fibroblasts, pathways related to cell adhesion in normal fibroblasts, and pathways related to ECM binding in fibroblasts treated with TGF-β1. Although transcriptomic profiles between scarred fibroblasts and fibroblasts treated with TGF-β1 were relatively dissimilar, the most highly co-expressed genes were enriched in pathways related to actin cytoskeleton binding. Conclusions: Transcriptomics of normal fibroblasts differ from myofibroblasts, including from those retrieved from scar and those treated with TGF-β1. Despite large differences in transcriptomics between tVFF and sVFF, tVFF serve as a useful in vitro model of myofibroblasts and highlight key similarities to myofibroblasts extracted from scar pathology, as well as expected differences related to normal fibroblasts from healthy VF.
Project description:Cancer-associated fibroblasts are a major component of the cancer stroma. Here we focus on gastric cancer associated myofibroblasts (CAMs). CAMs secrete factors that increase the migration, invasion and proliferation of cancer cells when compared to adjacent tissue myofibroblasts (ATMs), or normal tissue myofibroblasts (NTMs). In this study we identified and quantified the proteins secreted by normoxic (21% O2) and hypoxic (1% O2) myofibroblast cells.
Project description:Recent studies demonstrated that metabolic disturbance, such as augmented glycolysis, contributes to fibrosis. The molecular regulation of this metabolic perturbation in fibrosis, however, has been elusive. COUP-TFII (also known as NR2F2) is an important regulator of glucose and lipid metabolism. Its contribution to organ fibrosis is undefined. Here, we found increased COUP-TFII expression in myofibroblasts in human fibrotic kidneys, lungs, kidney organoids, and mouse kidneys after injury. Genetic ablation of COUP-TFII in mice resulted in attenuation of injury-induced kidney fibrosis. A non-biased proteomic study revealed the suppression of fatty acid oxidation and the enhancement of glycolysis pathways in COUP-TFII overexpressing fibroblasts. Overexpression of COUP-TFII in fibroblasts induced augmented glycolysis and production of alpha smooth muscle actin (αSMA) and collagen1. Knockout of COUP-TFII decreased glycolysis and collagen1 levels in fibroblasts. Chip-qPCR revealed the binding of COUP-TFII on the promoter of PGC1α. Overexpression of COUP-TFII reduced the cellular level of PGC1α. Targeting COUP-TFII serves as a novel treatment approach for mitigating fibrosis in chronic kidney disease and potentially fibrosis in other organs.
Project description:After stromal injury to the cornea, the release of growth factors and pro-inflammatory cytokines promotes the activation of quiescent keratocytes into a migratory fibroblast and/or fibrotic myofibroblast phenotype. Persistence of the myofibroblast phenotype can lead to corneal fibrosis and scarring, which are leading causes of blindness worldwide. This study aims to establish comprehensive transcriptional profiles for cultured corneal keratocytes, fibroblasts, and myofibroblasts to gain insights into the mechanisms through which these phenotypic changes occur. Primary rabbit corneal keratocytes were cultured in either defined serum-free media (SF), fetal bovine serum (FBS) containing media, or in the presence of TGF-β1 to induce keratocyte, fibroblast, or myofibroblast phenotypes, respectively. Bulk RNA sequencing followed by bioinformatic analyses was performed to identify significant differentially expressed genes (DEGs) and enriched biological pathways for each phenotype. Genes commonly associated with keratocytes, fibroblasts, or myofibroblasts showed high relative expression in SF, FBS, or TGF-β1 culture conditions, respectively. Differential expression and functional analyses revealed novel DEGs for each cell type, as well as enriched pathways indicative of differences in proliferation, apoptosis, extracellular matrix (ECM) synthesis, cell-ECM interactions, cytokine signaling, and cell mechanics. Overall, these data demonstrate distinct transcriptional differences among cultured corneal keratocytes, fibroblasts, and myofibroblasts. We have identified genes and signaling pathways that may play important roles in keratocyte differentiation, including many related to mechanotransduction and ECM biology. Our findings have revealed novel molecular markers for each cell type, as well as possible targets for modulating cell behavior and promoting physiological corneal wound healing.
Project description:ABSTRACT Background: Human breast cancer most frequently originates within a well-defined anatomical structure referred to as the terminal duct lobular unit (TDLU). This structure is endowed with its very own lobular fibroblasts representing one out of two steady-state fibroblast subtypes – the other being interlobular fibroblasts. While cancer associated fibroblasts (CAFs) are increasingly appreciated as covering a spectrum of perturbed states, we lack a coherent understanding of their relationship – if any - with the steady-state fibroblast subtypes. To address this, we here established two autologous CAF lines representing inflammatory CAFs (iCAFs) and myofibroblast CAFs (myCAFs), and compared them with already established interlobular- and lobular fibroblasts with respect to their origin and impact on tumor formation. Methods: Primary breast tumor derived CAFs were transduced to express human telomerase reverse transcriptase (hTERT) and sorted into CD105low and CD105high populations using fluorescence activated cell sorting (FACS). The two populations were tested for differentiation similarities to iCAF and myCAF states through transcriptome-wide RNA-Sequencing (RNA-Seq) including comparison to an available iCAF-myCAF cell state atlas. Inference of origin in interlobular and lobular fibroblasts relied on RNA-seq profiles, immunocytochemistry and growth characteristics. Osteogenic differentiation and bone formation assays in culture and in vivo were employed to gauge for origin in bone marrow mesenchymal stem cells (bMSCs). Functional characteristics were assessed with respect to contractility in culture and interaction with tumor cells in mouse xenografts. The cells’ gene expression signatures were tested for association with clinical outcome of breast cancer patients using survival data in The Cancer Genome Atlas database (TCGA). Results: We demonstrate that iCAFs have properties in common with interlobular fibroblasts while myCAFs and lobular fibroblasts are related. None of the CAFs qualify as bMSCs as revealed by lack of critical performance in bone formation assays. Functionally, myCAFs and lobular fibroblasts are almost equally tumor promoting as opposed to iCAFs and interlobular fibroblasts. A myCAF gene signature is found to associate with poor breast cancer specific survival. Conclusions: We propose that iCAFs and myCAFs originate in interlobular and lobular fibroblasts, respectively, and more importantly, that the tumor promoting properties of lobular fibroblasts renders the TDLU an epicenter for breast cancer evolution.
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:Myofibroblasts are fibroblastic cells that function in wound healing, tissue repair and fibrosis, and are derived from bone marrow (BM) and a variety of local progenitor cells. In the cornea, myofibroblasts are derived primarily from stromal keratocytes and from BM-derived fibrocytes after epithelial-stromal and endothelial-stromal injuries. Quantitative proteomic comparison of mature alpha-smooth muscle actin (alpha-SMA)+ myofibroblasts from rabbit cornea and BM was pursued for insights into possible functional differences. Cornea- and BM-derived alpha-SMA+ myofibroblast primary cultures were generated from four New Zealand white rabbits and confirmed to be myofibroblasts by immunocytochemistry. Paired cornea- and BM-derived myofibroblast specimens from each rabbit were analyzed by LC MS/MS iTRAQ technology using an Orbitrap Fusion Lumos Tribrid mass spectrometer, the Mascot search engine, the weighted average quantification method and the UniProt rabbit and human databases. From 2329 proteins quantified with >= 2 unique peptides from >= 3 rabbits, a total of 673 differentially expressed (DE) proteins were identified. Bioinformatic analysis of DE proteins with Ingenunity Pathway Analsysis implicate progenitor-dependent functional differences in myofibroblasts that could impact tissue development. Our results suggest BM-derived myofibroblasts may be more prone to the formation of excessive cellular and extracellular material that are characteristic of fibrosis.