Project description:Tumor microenvironment contains various components including cancer cells, tumor vessels, and cancer associated fibroblasts (CAFs), comprising of tumor-promoting myofibroblasts and tumor-suppressing fibroblasts. Multiple lines of evidence indicated that transforming growth factor-β (TGF-β) induces the formation of myofibroblasts and other types of mesenchymal (non-myofibroblastic) cells from endothelial cells. Recent reports showed that fibroblast growth factor 2 (FGF2) modulates TGF-β-induced mesenchymal transition of endothelial cells, but the molecular mechanisms regarding the signals that control the transcriptional networks during the formation of different groups of fibroblasts remain largely unclear. Here, we studied the roles of FGF2 during the regulation of TGF-β-induced mesenchymal transition of tumor endothelial cells (TECs). We demonstrated that auto/paracrine FGF signals in TECs inhibit TGF-β-induced endothelial-to-myofibroblast transition (End-MyoT), leading to suppressed formation of contractile myofibroblast cells, but on the other hand can also collaborate with TGF-β in promoting the formation of active fibroblastic cells which have migratory and proliferative properties. FGF2 modulated TGF-β-induced formation of myofibroblastic and non-myofibroblastic cells from TECs via transcriptional regulation of the array of various mesenchymal markers and growth factors. Furthermore, we observed that TECs treated with TGF-β were more competent in promoting in vivo tumor growth than TECs treated with TGF-β and FGF2. Mechanistically, we showed that Elk1 mediated this FGF2-induced inhibition of End-MyoT via inhibition of TGF-β-induced transcriptional activation of α-SMA promoter by myocardin-related transcription factor (MRTF)-A. Our data suggest that TGF-β and FGF2 oppose and cooperate with each other during the formation of myofibroblastic and non-myofibroblastic cells from TECs to determine the characteristics of the mesenchymal cells in tumor microenvironment. Identification of marker genes for TGF-β-induced endothelial-to-myofibroblast transition
Project description:Glioma-associated oncogene homolog-1 (Gli1)-positive resident mesenchymal stem cell-like cells are the predominant source of kidney myofibroblasts in fibrosis, but investigating Gli1-positive myofibroblast progenitor activation is hampered by the difficulty of isolating and propagating primary cultures of these cells. Using a genetic strategy with positive and negative selection, we isolated Kidney-Gli1 (KGli1) cells that maintain expression of appropriate mesenchymal stem cell-like cell markers, respond to hedgehog pathway activation, and display robust myofibroblast differentiation upon treatment with transforming growth factor-β (TGF-β). Coculture of KGli1 cells with endothelium stabilizes capillary formation. Single-cell RNA sequencing (scRNA-seq) analysis during differentiation identified autocrine ligand-receptor pair upregulation and a strong focal adhesion pathway signal. This led us to test the serum response factor inhibitor CCG-203971 that potently inhibited TGF-β-induced pericyte-to-myofibroblast transition. scRNA-seq also identified the unexpected upregulation of nerve growth factor (NGF), which we confirmed in two mouse kidney fibrosis models. The Ngf receptor Ntrk1 is expressed in tubular epithelium in vivo, suggesting a novel interstitial-to-tubule paracrine signaling axis. Thus, KGli1 cells accurately model myofibroblast activation in vitro, and the development of this cell line provides a new tool to study resident mesenchymal stem cell-like progenitors in health and disease.
Project description:Analysis of primary bovine aortic endothelial cells treated for 24 hours with TGF-beta 1 5 ng/ml. TGF-beta 1 has been shown to induce endothelial-to-mesenchymal transition (EndoMT) and to be implicated in differentiation of endothelial cells into smooth muscle-like cells as occurred in vascular neointimal formation. Primary aortic endothelial cells seeded on 10 mm diameter plates were incubated with TGF-beta 1 (5 ng/ml) for 24 hours or left under basal conditions. Triplicates from three different cultures.
Project description:Endothelial to mesenchymal transition (EndoMT) plays a key role in heart development, but is also implicated in cardiovascular diseases in postnatal life. While the roles of TGF-β as inducer of EndoMT on the transcriptional level are well characterised, its post-transcriptional regulatory mechanisms remain largely unknown. Here, we identified global changes in the endothelial mRNA bound proteome upon TGF-β stimulation using RNA interactome capture. Characterisation of TGF-β regulated RNA binding proteins (RBPs) revealed heterogeneous nuclear ribonucleoprotein H1 (hnRNP H1) and Cold Shock Domain Containing E1 (Csde1) as key regulators of endothelial function and EndoMT. We profiled TGF-β driven changes in the RNA binding patterns of hnRNP H1 and Csde1 and found that they dynamically bind and regulate specific subsets of functionally connected RNAs related to mesenchymal activation upon TGF-β stimulation. Together, we show that RBPs play a key role in EndoMT and that the RBPs hnRNP H1 and Csde1 maintain endothelial cell function and counteract mesenchymal activation.
Project description:Endothelial to mesenchymal transition (EndoMT) plays a key role in heart development, but is also implicated in cardiovascular diseases in postnatal life. While the roles of TGF-β as inducer of EndoMT on the transcriptional level are well characterised, its post-transcriptional regulatory mechanisms remain largely unknown. Here, we identified global changes in the endothelial mRNA bound proteome upon TGF-β stimulation using RNA interactome capture. Characterisation of TGF-β regulated RNA binding proteins (RBPs) revealed heterogeneous nuclear ribonucleoprotein H1 (hnRNP H1) and Cold Shock Domain Containing E1 (Csde1) as key regulators of endothelial function and EndoMT. We profiled TGF-β driven changes in the RNA binding patterns of hnRNP H1 and Csde1 and found that they dynamically bind and regulate specific subsets of functionally connected RNAs related to mesenchymal activation upon TGF-β stimulation. Together, we show that RBPs play a key role in EndoMT and that the RBPs hnRNP H1 and Csde1 maintain endothelial cell function and counteract mesenchymal activation.
Project description:Analysis of primary bovine aortic endothelial cells treated for 24 hours with TGF-beta 1 5 ng/ml. TGF-beta 1 has been shown to induce endothelial-to-mesenchymal transition (EndoMT) and to be implicated in differentiation of endothelial cells into smooth muscle-like cells as occurred in vascular neointimal formation.
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:Background:This study investigated if and how atrial endothelial cells may transform to mesenchymal cells and contribute to atrial fibrosis via endothelial-to-mesenchymal transition (EndMT). Results:We show a novel mechanistic link between TGF-β1/SMAD signaling and decreased Sema3a expression through the induction of miR-181b; this pathway plays an important role in EndMT associated with the pathogenesis of AF. Both miR-181b and Sema3a are potential therapeutic targets in AF.
Project description:Background:This study investigated if and how atrial endothelial cells may transform to mesenchymal cells and contribute to atrial fibrosis via endothelial-to-mesenchymal transition (EndMT). Results:We show a novel mechanistic link between TGF-β1/SMAD signaling and decreased Sema3a expression through the induction of miR-181b; this pathway plays an important role in EndMT associated with the pathogenesis of AF. Both miR-181b and Sema3a are potential therapeutic targets in AF.