Role of integrin-mediated TGFβ activation in the pathogenesis of pulmonary fibrosis

2009 ◽  
Vol 37 (4) ◽  
pp. 849-854 ◽  
Author(s):  
Amanda Goodwin ◽  
Gisli Jenkins
Keyword(s):  
Pulmonary Fibrosis ◽  
Transforming Growth Factor ◽  
Epithelial Mesenchymal Transition ◽  
Transforming Growth Factor Β ◽  
Normal Lung ◽  
Membrane Repair ◽  
Mesenchymal Transition ◽  
Chronic Progressive Disease ◽  
Activation Pathways

IPF (idiopathic pulmonary fibrosis) is a chronic progressive disease of unknown aetiology without effective treatment. IPF is characterized by excessive collagen deposition within the lung. Recent evidence suggests that the lung epithelium plays a key role in driving the fibrotic response. The current paradigm suggests that, after epithelial injury, there is impaired epithelial proliferation and enhanced epithelial apoptosis. This in turn promotes lung fibrosis through impaired basement membrane repair and increased epithelial–mesenchymal transition. Furthermore, fibroblasts are recruited to the wounded area and adopt a myofibroblast phenotype, with the up-regulation of matrix-synthesizing genes and down-regulation of matrix-degradation genes. There is compelling evidence that the cytokine TGFβ (transforming growth factor β) plays a central role in this process. In normal lung, TGFβ is maintained in an inactive state that is tightly regulated temporally and spatially. One of the major TGFβ-activation pathways involves integrins, and the role of the αvβ6 integrin has been particularly well described in the pathogenesis of IPF. Owing to the pleiotropic nature of TGFβ, strategies that inhibit activation of TGFβ in a cell- or disease-specific manner are attractive for the treatment of chronic fibrotic lung conditions. Therefore the molecular pathways that lead to integrin-mediated TGFβ activation must be precisely defined to identify and fully exploit novel therapeutic targets that might ultimately improve the prognosis for patients with IPF.

Fibroblasts positive for meflin have anti-fibrotic property in pulmonary fibrosis

2021 ◽  
pp. 2003397
Author(s):  
Yoshio Nakahara ◽  
Naozumi Hashimoto ◽  
Koji Sakamoto ◽  
Atsushi Enomoto ◽  
Taylor S. Adams ◽  
...  
Keyword(s):  
Pulmonary Fibrosis ◽  
Single Cell ◽  
Transforming Growth Factor ◽  
Transforming Growth Factor Β ◽  
Normal Lung ◽  
Potential Marker ◽  
Rna Hybridisation ◽  
Secretory Phenotype

The prognosis of elderly individuals with idiopathic pulmonary fibrosis (IPF) remains poor. Fibroblastic foci, in which aggregates of proliferating fibroblasts and myofibroblasts are involved, are the pathological hallmark lesions in IPF to represent focal areas of active fibrogenesis. Fibroblast heterogeneity in fibrotic lesions hampers the discovery of the pathogenesis of pulmonary fibrosis. Therefore, to determine of the pathogenesis of IPF, identification of functional fibroblasts is warranted. This study was aimed to determine the role of fibroblasts positive for meflin, identified as a potential marker for mesenchymal stromal cells, during the development of pulmonary fibrosis. We characterised meflin-positive cells in a single cell atlas established by single-cell RNA sequencing (scRNA-seq)-based profiling of 243 472 cells from 32 IPF lungs and 29 normal lung samples. scRNA-seq combined with in situ RNA hybridisation identified proliferating fibroblasts positive for meflin in fibroblastic foci, not dense fibrosis, of fibrotic lungs in IPF patients. We determined the role of fibroblasts positive for meflin using bleomycin (BLM)-induced pulmonary fibrosis. A BLM-induced lung fibrosis model for meflin-deficient mice showed that fibroblasts positive for meflin had anti-fibrotic property to prevent pulmonary fibrosis. Although transforming growth factor-β-induced fibrogenesis and cell senescence with senescence-associated secretory phenotype were exacerbated in fibroblasts via the repression or lack of meflin, these were inhibited in meflin-deficient fibroblasts with meflin reconstitution. These findings provide evidence to show the biological importance of meflin expression on fibroblasts and myofibroblasts in the active fibrotic region of pulmonary fibrosis.

Intratubular epithelial-mesenchymal transition and tubular atrophy after kidney injury in mice

2020 ◽  
Vol 319 (4) ◽  
pp. F579-F591
Author(s):  
Noriyuki Yamashita ◽  
Tetsuro Kusaba ◽  
Tomohiro Nakata ◽  
Aya Tomita ◽  
Tomoharu Ida ◽  
...  
Keyword(s):  
Growth Factor ◽  
Acute Phase ◽  
Transforming Growth Factor ◽  
Epithelial Mesenchymal Transition ◽  
Chronic Phase ◽  
Transforming Growth Factor Β ◽  
Tubular Atrophy ◽  
Mesenchymal Transition

Tubular atrophy is a common pathological feature of kidney fibrosis. Although fibroblasts play a predominant role in tissue fibrosis, the role of repairing tubular epithelia in tubular atrophy is unclear. We demonstrated the essential role of focal adhesion kinase (FAK)-mediated intratubular epithelial-mesenchymal transition (EMT) in the pathogenesis of tubular atrophy after severe ischemia-reperfusion injury (IRI). Actively proliferating tubular epithelia undergoing intratubular EMT were noted in the acute phase of severe IRI, resulting in tubular atrophy in the chronic phase, reflecting failed tubular repair. Furthermore, FAK was phosphorylated in the tubular epithelia in the acute phase of severe IRI, and its inhibition ameliorated both tubular atrophy and interstitial fibrosis in the chronic phase after injury. In vivo clonal analysis of single-labeled proximal tubular epithelial cells after IRI using proximal tubule reporter mice revealed substantial clonal expansion after IRI, reflecting active epithelial proliferation during repair. The majority of these proliferating epithelia were located in atrophic and nonfunctional tubules, and FAK inhibition was sufficient to prevent tubular atrophy. In vitro, transforming growth factor-β induced FAK phosphorylation and an EMT phenotype, which was also prevented by FAK inhibition. In an in vitro tubular epithelia gel contraction assay, transforming growth factor-β treatment accelerated gel contraction, which was suppressed by FAK inhibition. In conclusion, injury-induced intratubular EMT is closely related to tubular atrophy in a FAK-dependent manner.

scholarly journals Downregulation of S100A2 alleviates pulmonary fibrosis through inhibiting wnt/β-catenin signaling pathway

2020 ◽  
Author(s):  
Guichuan Huang ◽  
Jing Zhang ◽  
Gang Qing ◽  
Daishun Liu ◽  
Xin Wang ◽  
...  
Keyword(s):  
Pulmonary Fibrosis ◽  
Western Blot ◽  
Molecular Mechanisms ◽  
Transforming Growth Factor ◽  
Epithelial Mesenchymal Transition ◽  
A549 Cells ◽  
Mesenchymal Transition ◽  
Qrt Pcr ◽  
Tgf Β1

Abstract Background：Pulmonary fibrosis (PF) is a progressive and lethal disease with poor prognosis. S100A2 plays an important role in the progression of cancer. However, the role of S100A2 in PF has not been reported yet. In this study, we explored the potential role of S100A2 in PF and its potential molecular mechanisms. Methods: First, we analyzed S100A2 expression of patients with PF by retrieving RNA-sequencing datasets from Gene Expression Omnibus (GEO) database. Next, we detected the expression of S100A2 in patients with PF using quantitative real time PCR (qRT-PCR). Then, S100A2 expression was determined with or without the treatment of transforming growth factor-β1 (TGF-β1) in A549 cells. Epithelial-mesenchymal transition (EMT) biomarkers, including E-cadherin，vimentin, and α smooth muscle actin (α-SMA), were identified using qRT-PCR and western blot. Finally, the relevant signalling pathway indicators were detected by western blot. Results: Increased expression of S100A2 was first observed in lung tissues of PF patients. Meanwhile, we found that downregulation of S100A2 inhibited the TGF-β1-induced EMT in A549 cells. Mechanically, TGF-β1 up-regulated β-catenin and phosphorylation of GSK-3β, which was blocked by silencing S100A2 in vitro. Conclusion: These findings demonstrate that downregulation of S100A2 alleviate pulmonary fibrosis via inhibiting EMT. S100A2 is a promising potential target for further understanding the mechanism and developing strategy for the treatment of PF and other EMT-associated disease.

scholarly journals Death-Associated Protein 6 (Daxx) Alleviates Liver Fibrosis by Modulating Smad2 Acetylation

Cells ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1742
Author(s):  
Sung-Min Kim ◽  
Won-Hee Hur ◽  
Byung-Yoon Kang ◽  
Sung-Won Lee ◽  
Pu-Reun Roh ◽  
...  
Keyword(s):  
Liver Fibrosis ◽  
Mouse Model ◽  
Transforming Growth Factor ◽  
Epithelial Mesenchymal Transition ◽  
Transforming Growth Factor Β ◽  
Apoptotic Pathway ◽  
Mesenchymal Transition ◽  
Pathway Activation

Transforming growth factor-β (TGF-β) has been identified as an inducer of hepatocyte epithelial–mesenchymal transition (EMT), which triggers liver fibrosis. Death-associated protein 6 (Daxx) is known to be associated with the TGF-β-induced apoptotic pathway, but the function of Daxx in liver fibrosis remains unknown. This study aimed to elucidate the role of Daxx in liver fibrosis. We used liver fibrosis tissues from humans and mice to assess Daxx expression. EMT properties and TGF-β signaling pathway activation were investigated in the Daxx-overexpressing FL83B cell line. The therapeutic effect of Daxx was investigated in a mouse model of liver fibrosis by the hydrodynamic injection of plasmids. The expression of Daxx was markedly decreased in hepatocytes from fibrotic human and mouse livers, as well as in hepatocytes treated with TGF-β in vitro. The overexpression of Daxx inhibited the EMT process by interfering with the TGF-β-induced phosphorylation of Smad2. Coimmunoprecipitation analysis confirmed that Daxx reduced the transcriptional activity of Smad2 by binding to its MH1 domain and interfering with Smad2 acetylation. In addition, the therapeutic delivery of Daxx alleviated liver fibrosis in a thioacetamide-induced fibrosis mouse model. Overall, our results indicate that Daxx could be a potential therapeutic target to modulate fibrogenesis, as well as a useful biomarker for liver fibrosis.

scholarly journals LncRNA SNHG16 promotes pulmonary fibrosis by targeting miR-455-3p to regulate the Notch2 pathway

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Panpan Liu ◽  
Lei Zhao ◽  
Yuxia Gu ◽  
Meilan Zhang ◽  
Hongchang Gao ◽  
...  
Keyword(s):  
Pulmonary Fibrosis ◽  
Lung Fibrosis ◽  
Transforming Growth Factor ◽  
Transforming Growth Factor Β ◽  
Interstitial Lung Diseases ◽  
Luciferase Reporter ◽  
Qrt Pcr ◽  
Rna Immunoprecipitation ◽  
And Migration

Abstract Background Idiopathic pulmonary fibrosis (IPF) is the most common interstitial lung diseases with a poor prognosis. Long non-coding RNAs (lncRNAs) have been reported to be involved in IPF in several studies. However, the role of lncRNA SNHG16 in IPF is largely unknown. Methods Firstly, experimental pulmonary fibrosis model was established by using bleomycin (BML). Histology and Western blotting assays were used to determine the different stages of fibrosis and expression of several fibrosis biomarkers. The expression of SNHG16 was detected by quantitative real-time polymerase chain reaction (qRT‐PCR). EdU staining and wound-healing assay were utilized to analyze proliferation and migration of lung fibroblast cells. Molecular mechanism of SNHG16 was explored by bioinformatics, dual-luciferase reporter assay, RNA immunoprecipitation assay (RIP), and qRT-PCR. Results The expression of SNHG16 was significantly up-regulated in bleomycin-(BLM) induced lung fibrosis and transforming growth factor-β (TGF-β)-induced fibroblast. Knockdown of SNHG16 could attenuate fibrogenesis. Mechanistically, SNHG16 was able to bind and regulate the expression of miR-455-3p. Moreover, SNHG16 also regulated the expression of Notch2 by targeting miR-455-3p. Finally, SNHG16 could promote fibrogenesis by regulating the expression of Notch2. Conclusion Taken together, our study demonstrated that SNHG16 promoted pulmonary fibrosis by targeting miR-455-3p to regulate the Notch2 pathway. These findings might provide a novel insight into pathologic process of lung fibrosis and may provide prevention strategies in the future.

scholarly journals The Molecular Mechanism of Epithelial–Mesenchymal Transition for Breast Carcinogenesis

Biomolecules ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 476 ◽  
Author(s):  
Chia-Jung Li ◽  
Pei-Yi Chu ◽  
Giou-Teng Yiang ◽  
Meng-Yu Wu
Keyword(s):  
Epithelial Cells ◽  
Tumor Progression ◽  
Signaling Pathways ◽  
Intracellular Signaling ◽  
Molecular Mechanisms ◽  
Transforming Growth Factor ◽  
Epithelial Mesenchymal Transition ◽  
Transforming Growth Factor Β ◽  
Inhibition Of Proliferation ◽  
Mesenchymal Transition

The transforming growth factor-β (TGF-β) signaling pathway plays multiple regulatory roles in the tumorigenesis and development of cancer. TGF-β can inhibit the growth and proliferation of epithelial cells and induce apoptosis, thereby playing a role in inhibiting breast cancer. Therefore, the loss of response in epithelial cells that leads to the inhibition of cell proliferation due to TGF-β is a landmark event in tumorigenesis. As tumors progress, TGF-β can promote tumor cell invasion, metastasis, and drug resistance. At present, the above-mentioned role of TGF-β is related to the interaction of multiple signaling pathways in the cell, which can attenuate or abolish the inhibition of proliferation and apoptosis-promoting effects of TGF-β and enhance its promotion of tumor progression. This article focuses on the molecular mechanisms through which TGF-β interacts with multiple intracellular signaling pathways in tumor progression and the effects of these interactions on tumorigenesis.

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