scholarly journals TGF-β Signaling and the Epithelial-Mesenchymal Transition during Palatal Fusion

2018 ◽  
Vol 19 (11) ◽  
pp. 3638 ◽  
Author(s):  
Akira Nakajima ◽  
Charles F. Shuler ◽  
Alexander Gulka ◽  
Jun-ichi Hanai

Signaling by transforming growth factor (TGF)-β plays an important role in development, including in palatogenesis. The dynamic morphological process of palatal fusion occurs to achieve separation of the nasal and oral cavities. Critically and specifically important in palatal fusion are the medial edge epithelial (MEE) cells, which are initially present at the palatal midline seam and over the course of the palate fusion process are lost from the seam, due to cell migration, epithelial-mesenchymal transition (EMT), and/or programed cell death. In order to define the role of TGF-β signaling during this process, several approaches have been utilized, including a small interfering RNA (siRNA) strategy targeting TGF-β receptors in an organ culture context, the use of genetically engineered mice, such as Wnt1-cre/R26R double transgenic mice, and a cell fate tracing through utilization of cell lineage markers. These approaches have permitted investigators to distinguish some specific traits of well-defined cell populations throughout the palatogenic events. In this paper, we summarize the current understanding on the role of TGF-β signaling, and specifically its association with MEE cell fate during palatal fusion. TGF-β is highly regulated both temporally and spatially, with TGF-β3 and Smad2 being the preferentially expressed signaling molecules in the critical cells of the fusion processes. Interestingly, the accessory receptor, TGF-β type 3 receptor, is also critical for palatal fusion, with evidence for its significance provided by Cre-lox systems and siRNA approaches. This suggests the high demand of ligand for this fine-tuned signaling process. We discuss the new insights in the fate of MEE cells in the midline epithelial seam (MES) during the palate fusion process, with a particular focus on the role of TGF-β signaling.

2011 ◽  
Vol 300 (4) ◽  
pp. F1017-F1025 ◽  
Author(s):  
Hongli Lin ◽  
Dapeng Wang ◽  
Taihua Wu ◽  
Cui Dong ◽  
Nan Shen ◽  
...  

Posttranslational modification of proteins could regulate their multiple biological functions. Transforming growth factor-β receptor I and II (ALK5 and TGF-βRII), which are glycoproteins, play important roles in the renal tubular epithelial-mesenchymal transition (EMT). In the present study, we examined the role of core fucosylation of TGF-βRII and ALK5, which is regulated by α-1,6 fucosyltransferase (Fut8), in the process of EMT of cultured human renal proximal tubular epithelial (HK-2) cells. The typical cell model of EMT induced by TGF-β1 was constructed to address the role of core fucosylation in EMT. Core fucosylation was found to be essential for both TGF-βRII and ALK5 to fulfill their functions, and blocking it with Fut8 small interfering RNA greatly reduced the phosphorylation of Smad2/3 protein, caused the inactivation of TGF-β/Smad2/3 signaling, and resulted in remission of EMT. More importantly, even with high levels of expressions of TGF-β1, TGF-βRII, and ALK5, blocking core fucosylation also could attenuate the EMT of HK-2 cells. Thus blocking core fucosylation of TGF-βRII and ALK5 may attenuate EMT independently of the expression of these proteins. This study may provide new insight into the role of glycosylation in renal interstitial fibrosis. Furthermore, core fucosylation may be a novel potential therapeutic target for treatment of renal tubular EMT.


2007 ◽  
Vol 293 (3) ◽  
pp. L525-L534 ◽  
Author(s):  
Brigham C. Willis ◽  
Zea Borok

Epithelial-mesenchymal transition (EMT), a process whereby fully differentiated epithelial cells undergo transition to a mesenchymal phenotype giving rise to fibroblasts and myofibroblasts, is increasingly recognized as playing an important role in repair and scar formation following epithelial injury. The extent to which this process contributes to fibrosis following injury in the lung is a subject of active investigation. Recently, it was demonstrated that transforming growth factor (TGF)-β induces EMT in alveolar epithelial cells (AEC) in vitro and in vivo, and epithelial and mesenchymal markers have been colocalized to hyperplastic type II (AT2) cells in lung tissue from patients with idiopathic pulmonary fibrosis (IPF), suggesting that AEC may exhibit extreme plasticity and serve as a source of fibroblasts and/or myofibroblasts in lung fibrosis. In this review, we describe the characteristic features of EMT and its mechanistic underpinnings. We further describe the contribution of EMT to fibrosis in adult tissues following injury, focusing especially on the critical role of TGF-β and its downstream mediators in this process. Finally, we highlight recent descriptions of EMT in the lung and the potential implications of this process for the treatment of fibrotic lung disease. Treatment for fibrosis of the lung in diseases such as IPF has heretofore focused largely on amelioration of potential inciting processes such as inflammation. It is hoped that this review will stimulate further consideration of the cellular mechanisms of fibrogenesis in the lung and especially the role of the epithelium in this process, potentially leading to innovative avenues of investigation and treatment.


2018 ◽  
Vol 64 (1) ◽  
pp. 62-72
Author(s):  
V. Shcherbakov ◽  
T. Ryabichenko ◽  
G. Skosyreva ◽  
A. Trunov

The review considered the issues of epithelial-mesenchymal transition (EMT) and its role in inflammation, fibrosis, tumor growth. There were analyzed mechanisms and classification of EMT. A comparison of different forms of EMTs was performed. The important role of EMT in the formation of metastasis-initiating cells was noted. There were presented data on the role of fibroblasts in fibrosis of the lung, carcinogenesis. Stimulators and inhibitors of EMTs were summarized. There were considered intracellular paths that were associated with the development of the EMT under the influence of transforming growth factor ß1 (TGF - ß1). It also induced the development of local hypothyroidism, for easy expression of oncofetal genes, which was especially important in tumor growth. Therapy EMT was associated with blocking the actions of TGF - ß1 and was an important area in anticancer therapy.


2020 ◽  
Vol 319 (4) ◽  
pp. F579-F591
Author(s):  
Noriyuki Yamashita ◽  
Tetsuro Kusaba ◽  
Tomohiro Nakata ◽  
Aya Tomita ◽  
Tomoharu Ida ◽  
...  

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.


2009 ◽  
Vol 20 (22) ◽  
pp. 4751-4765 ◽  
Author(s):  
Ewa Kolosionek ◽  
Rajkumar Savai ◽  
Hossein Ardeschir Ghofrani ◽  
Norbert Weissmann ◽  
Andreas Guenther ◽  
...  

Epithelial–mesenchymal transition (EMT) has emerged as a critical event in the pathogenesis of organ fibrosis and cancer and is typically induced by the multifunctional cytokine transforming growth factor (TGF)-β1. The present study was undertaken to evaluate the potential role of phosphodiesterases (PDEs) in TGF-β1-induced EMT in the human alveolar epithelial type II cell line A549. Stimulation of A549 with TGF-β1 induced EMT by morphological alterations and by expression changes of the epithelial phenotype markers E-cadherin, cytokeratin-18, zona occludens-1, and the mesenchymal phenotype markers, collagen I, fibronectin, and α-smooth muscle actin. Interestingly, TGF-β1 stimulation caused twofold increase in total cAMP-PDE activity, contributed mostly by PDE4. Furthermore, mRNA and protein expression demonstrated up-regulation of PDE4A and PDE4D isoforms in TGF-β1-stimulated cells. Most importantly, treatment of TGF-β1 stimulated epithelial cells with the PDE4-selective inhibitor rolipram or PDE4 small interfering RNA potently inhibited EMT changes in a Smad-independent manner by decreasing reactive oxygen species, p38, and extracellular signal-regulated kinase phosphorylation. In contrast, the ectopic overexpression of PDE4A and/or PDE4D resulted in a significant loss of epithelial marker E-cadherin but did not result in changes of mesenchymal markers. In addition, Rho kinase signaling activated by TGF-β1 during EMT demonstrated to be a positive regulator of PDE4. Collectively, the findings presented herein suggest that TGF-β1 mediated up-regulation of PDE4 promotes EMT in alveolar epithelial cells. Thus, targeting PDE4 isoforms may be a novel approach to attenuate EMT-associated lung diseases such as pulmonary fibrosis and lung cancer.


2004 ◽  
Vol 24 (10) ◽  
pp. 4241-4254 ◽  
Author(s):  
Marcin Kowanetz ◽  
Ulrich Valcourt ◽  
Rosita Bergström ◽  
Carl-Henrik Heldin ◽  
Aristidis Moustakas

ABSTRACT Transforming growth factors β (TGF-βs) inhibit growth of epithelial cells and induce differentiation changes, such as epithelial-mesenchymal transition (EMT). On the other hand, bone morphogenetic proteins (BMPs) weakly affect epithelial cell growth and do not induce EMT. Smad4 transmits signals from both TGF-β and BMP pathways. Stimulation of Smad4-deficient epithelial cells with TGF-β1 or BMP-7 in the absence or presence of exogenous Smad4, followed by cDNA microarray analysis, revealed 173 mostly Smad4-dependent, TGF-β-, or BMP-responsive genes. Among 25 genes coregulated by both factors, inhibitors of differentiation Id2 and Id3 showed long-term repression by TGF-β and sustained induction by BMP. The opposing regulation of Id genes is critical for proliferative and differentiation responses. Hence, ectopic Id2 or Id3 expression renders epithelial cells refractory to growth inhibition and EMT induced by TGF-β, phenocopying the BMP response. Knockdown of endogenous Id2 or Id3 sensitizes epithelial cells to BMP, leading to robust growth inhibition and induction of transdifferentiation. Thus, Id genes sense Smad signals and create a permissive or refractory nuclear environment that defines decisions of cell fate and proliferation.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Yu Kyung Jun ◽  
So Hyun Kwon ◽  
Hee Tae Yoon ◽  
Hyunsun Park ◽  
Hosim Soh ◽  
...  

AbstractIntestinal fibrosis induced by chronic and recurrent colitis, which is exacerbated by bowel stenosis, stricture, and obstruction, is challenging to treat. Toll-like receptor 4 (TLR4) stimulates innate and acquired immunity in response to specific microbial components, but the role of TLR4 in intestinal fibrosis is largely unknown. We investigated its role in intestinal fibrosis using not only a murine fibrosis model but also human myofibroblasts and intestinal epithelial cells. Colon fibrosis was induced in TLR4-deficient (TLR4−/−) mice and its wild-type counterparts with 3% dextran sulfate sodium. Absence of TLR4 gene attenuated chronic inflammation and colonic macrophages infiltration; intestinal fibrosis and collagen deposition were suppressed. Also, the production of tumor necrosis factor-α, interleukin-12p40, and transforming growth factor-β was reduced in TLR4-deficient peritoneal macrophages. TLR4 was silenced in CCD-18Co cells by small interfering RNA (siRNA), and matrix metalloproteinase-1, tissue inhibitor of metalloproteinase, and collagen α1 expression was evaluated. Role of TLR4 in epithelial-mesenchymal transition (EMT) was evaluated in HCT116 cells. Suppression of TLR4 transcription by siRNAs affected myofibroblasts activity, collagen synthesis, and EMT in the human cancer cell line. Thus, we suggest that TLR4 can be an essential mediator in intestinal chronic inflammation and fibrosis, indicating that TLR4 signaling is a potential therapeutic target for intestinal fibrosis.


2020 ◽  
Author(s):  
Guichuan Huang ◽  
Jing Zhang ◽  
Gang Qing ◽  
Daishun Liu ◽  
Xin Wang ◽  
...  

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.


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