Project description:Myofibroblast is a specific type of mesenchymal cell characterized by synthesis of extracellular matrix and contractile activity. While it serves a beneficial function during tissue wound healing under physiological conditions, it can cause devastating damage to organs afflicted with fibrosis. Myofibroblasts are also present in tumor stroma and contribute actively to tumor growth and spreading. Chicken embryo dermal myofibroblasts (CEDM) represent a novel ex vivo model suitable for the analysis of myofibroblastic phenotype as they show strongly pronounced, uniform and self-sustained myofibroblastic phenotype that is stable in time. As myofibroblastic differentiation is controlled chiefly by TGF-beta signaling, the understanding of the differentiation program entails the determination of TGF-beta-regulated genes. To achieve such a goal, we performed oligonucleotide microarray analysis of CEDM cells treated with a selective TGFBR1 kinase inhibitor. Genes reported previously to be under the control of TGF-beta signaling in mammalian cells appeared among the affected genes also in CEDM cells and many so far unknown TGF-beta targets were revealed. Comparison of the expression profiles of chicken embryo dermal myofibroblasts in culture treated with TGFBR1 Kinase Inhibitor II or DMSO only. Three biological replicates were analyzed for each group.
Project description:Myofibroblast is a specific type of mesenchymal cell characterized by synthesis of extracellular matrix and contractile activity. While it serves a beneficial function during tissue wound healing under physiological conditions, it can cause devastating damage to organs afflicted with fibrosis. Myofibroblasts are also present in tumor stroma and contribute actively to tumor growth and spreading. Chicken embryo dermal myofibroblasts (CEDM) represent a novel ex vivo model suitable for the analysis of myofibroblastic phenotype as they show strongly pronounced, uniform and self-sustained myofibroblastic phenotype that is stable in time. As myofibroblastic differentiation is controlled chiefly by TGF-beta signaling, the understanding of the differentiation program entails the determination of TGF-beta-regulated genes. To achieve such a goal, we performed oligonucleotide microarray analysis of CEDM cells treated with a selective TGFBR1 kinase inhibitor. Genes reported previously to be under the control of TGF-beta signaling in mammalian cells appeared among the affected genes also in CEDM cells and many so far unknown TGF-beta targets were revealed.
Project description:Fibrotic diseases are a group of pathologies with high incidence and mortality. Despite extensive research efforts, efficient therapies are still not available. Understanding the molecular mechanisms driving the onset, progression and possible resolution of fibrosis is a prerequisite to the development of successful therapies. The central role of the TGF-beta pathway and myofibroblasts in the pathogenesis of fibrosis is now generally accepted. The possible mechanisms of myofibroblast elimination or dedifferentiation, on the other hand, are still almost uncharted territory. Basic fibroblast growth factor (bFGF) is able to suppress myofibroblastic differentiation of mesenchymal cells, but the underlying mechanism has not been studied in detail. Here, we show that sustained expression of the transcription factor EGR4, which is inducible by bFGF, in primary chicken embryo dermal myofibroblasts results in suppression of the myofibroblastic phenotype, characterized by the loss of smooth muscle actin fibers and a substantial reduction in the production of extracellular matrix. Detailed analysis of the possible molecular mechanisms revealed FOXG1, BAMBI, NAB1, NAB2 and DUSP5 genes forming an EGR4 regulated network counteracting autocrine TGF-beta signaling.
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:Repair of the infarcted heart requires TGFβ-Smad3 signaling in cardiac myofibroblasts. However, TGF-β-driven myofibroblast activation needs to be tightly regulated in order to prevent excessive fibrosis and adverse remodeling that may precipitate heart failure. We hypothesized that induction of the inhibitory Smad, Smad7 may restrain infarct myofibroblast activation, and we examined the molecular mechanisms of Smad7 actions. In a mouse model of non-reperfused infarction, Smad3 activation triggered Smad7 synthesis in β-SMA+ infarct myofibroblasts, but not in β-SMA-/PDGFRα+ fibroblasts. Myofibroblast-specific Smad7 loss increased heart failure-related mortality, worsened dysfunction, and accentuated fibrosis in the infarct border zone and in the papillary muscles. Smad7 attenuated myofibroblast activation and reduced synthesis of structural and matricellular extracellular matrix proteins. Smad7 actions on TGF-β cascades involved de-activation of Smad2/3 and non-Smad pathways, without any effects on TGF-β receptor activity. Unbiased transcriptomic and proteomic analysis identified receptor tyrosine kinase signaling as a major target of Smad7. Smad7 interacted with Erbb2 in a TGF-independent manner and restrained Erbb1/Erbb2 activation, suppressing fibroblast expression of fibrogenic proteases, integrins and CD44. Smad7 induction in myofibroblasts serves as an endogenous TGF-β-induced negative feedback mechanism that inhibits post-infarction fibrosis by restraining Smad-dependent and Smad-independent TGF-β responses, and by suppressing TGF-independent fibrogenic actions of Erbb2.
Project description:Tissue fibrosis is a common pathway to organ injury and failure. It is characterized by an excessive deposition of extracellular matrix (ECM) in organs. Deciphering the fibrogenic processes is of utmost importance, as there are few effective therapies in fibrotic diseases 1. Systemic sclerosis (SSc) is a prototypical disease where fibroblasts (Fb) are key effector cells as they differentiate into myofibroblasts in response to chronic inflammation under the influence of transforming growth factor beta 1 (TGF-β1) pathway 2–4. In this study, we compared the proteome of primary Fb in different culture and stimulation conditions. Primary dermal normal human Fb were cultured at passage P3, P5 and P7 with and without Fetal Bovine Serum (FBS). At fifth passage, Fb were stimulated or not with different concentrations of recombinant human active TGF-β1 (0.04, 1 and 5 ng/mL) during 24, 48 and 72 hours.