scholarly journals A small population of liver endothelial cells undergoes endothelial-to-mesenchymal transition in response to chronic liver injury

2017 ◽  
Vol 313 (5) ◽  
pp. G492-G504 ◽  
Author(s):  
Jordi Ribera ◽  
Montse Pauta ◽  
Pedro Melgar-Lesmes ◽  
Bernat Córdoba ◽  
Anna Bosch ◽  
...  

Rising evidence points to endothelial-to-mesenchymal transition (EndMT) as a significant source of the mesenchymal cell population in fibrotic diseases. In this context, we hypothesized that liver endothelial cells undergo EndMT during fibrosis progression. Cirrhosis in mice was induced by CCl4. A transgenic mouse expressing a red fluorescent protein reporter under the control of Tie2 promoter (Tie2-tdTomato) was used to trace the acquisition of EndMT. Sinusoidal vascular connectivity was evaluated by intravital microscopy and high-resolution three-dimensional confocal microscopy. A modest but significant fraction of liver endothelial cells from both cirrhotic patients and CCl4-treated Tie2-tdTomato mice acquired an EndMT phenotype characterized by the coexpression of CD31 and α-smooth muscle actin, compared with noncirrhotic livers. Bone morphogenetic protein-7 (BMP-7) inhibited the acquisition of EndMT induced by transforming growth factor-β1 (TGF-β1) treatment in cultured primary mouse liver endothelial cells from control mice. EndMT was also reduced significantly in vivo in cirrhotic Tie2-tdTomato mice treated intraperitoneally with BMP-7 compared with untreated mice (1.9 ± 0.2 vs. 3.8 ± 0.3%, respectively; P < 0.05). The decrease of EndMT in cirrhotic livers correlated with a significant decrease in liver fibrosis ( P < 0.05) and an improvement in the vascular disorganization rate ( P < 0.05). We demonstrated the acquisition of the EndMT phenotype by a subpopulation of endothelial cells from cirrhotic livers in both animal models and patients. BMP-7 treatment decreases the occurrence of the EndMT phenotype and has a positive impact on the severity of disease by reducing fibrosis and sinusoidal vascular disorganization. NEW & NOTEWORTHY A subpopulation of liver endothelial cells from cirrhotic patients and mice with liver fibrosis undergoes endothelial-to-mesenchymal transition. Liver endothelial cells from healthy mice could transition into a mesenchymal phenotype in culture in response to TGF-β1 treatment. Fibrotic livers treated chronically with BMP-7 showed lower EndMT acquisition, reduced fibrosis, and improved vascular organization.

Cardiology ◽  
2017 ◽  
Vol 137 (3) ◽  
pp. 179-187 ◽  
Author(s):  
Juling Feng ◽  
Jingjing Zhang ◽  
Ampadu O. Jackson ◽  
Xiao Zhu ◽  
Hainan Chen ◽  
...  

Objective: Transforming growth factor β1 (TGF-β1) is the major cytokine for stimulating endothelial cells (ECs) to transdifferentiate to mesenchymal cells (MCs) in the process known as endothelial-to-mesenchymal transition (EndMT). Recently, TGF-β1-induced EndMT has been implicated in the pathogenesis of atherosclerosis (AS). It has been identified that apolipoprotein A1 (ApoA-I) obstructs TGF-β1-induced endothelial dysfunction, providing a protective effect for ECs and also anti-AS activity. However, the exact role of ApoA-I in TGF-β1-induced EndMT is not clear. In this study, we aimed to investigate whether ApoA-I can modulate TGF-β1-induced EndMT in human coronary artery ECs (HCAECs). Methods and Results: The HCAECs were treated with TGF-β1 with or without ApoA-I. Morphological changes in HCAECs and the expression of EndMT-related markers were evaluated. HCAECs treated with TGF-β1 were found to transform to MC morphology, with inconspicuous expression of EC markers such as vascular endothelial cadherin and CD31, and conspicuous expression of fibroblast-specific protein 1 (FSP-1) and α-smooth muscle actin. The treatment of HCAECs with ApoA-I inhibited the TGF-β1-induced EndMT, and elevated expression of EC markers was observed but reduced expression of MC markers. Moreover, ApoA-I impeded the expression level of Slug and Snail, crucial transcriptional factors of EndMT, and it inhibited the TGF-β1-induced phosphorylation of Smad2 and Smad3 which affected the EC morphology. In addition, the knockdown of ABCA1 by RNA interference eliminated the inhibition effect of ApoA-I on TGF-β1-induced EndMT. Conclusions: Our findings revealed a novel mechanism for the ApoA-I protective effect on endothelium function via the inhibition of TGF-β1-induced EndMT. This might provide new insights for developing strategies for modulating AS and vascular remodeling.


2019 ◽  
Vol 20 (3) ◽  
pp. 458 ◽  
Author(s):  
Fernanda Ursoli Ferreira ◽  
Lucas Eduardo Botelho Souza ◽  
Carolina Hassibe Thomé ◽  
Mariana Tomazini Pinto ◽  
Clarice Origassa ◽  
...  

The endothelial-to-mesenchymal transition (EndMT) is a biological process where endothelial cells (ECs) acquire a fibroblastic phenotype after concomitant loss of the apical-basal polarity and intercellular junction proteins. This process is critical to embryonic development and is involved in diseases such as fibrosis and tumor progression. The signaling pathway of the transforming growth factor β (TGF-β) is an important molecular route responsible for EndMT activation. However, it is unclear whether the anatomic location of endothelial cells influences the activation of molecular pathways responsible for EndMT induction. Our study investigated the molecular mechanisms and signaling pathways involved in EndMT induced by TGF-β2 in macrovascular ECs obtained from different sources. For this purpose, we used four types of endothelial cells (coronary artery endothelial cells, CAECs; primary aortic endothelial cells PAECs; human umbilical vein endothelia cells, HUVECs; and human pulmonary artery endothelial cells, HPAECs) and stimulated with 10 ng/mL of TGF-β2. We observed that among the ECs analyzed in this study, PAECs showed the best response to the TGF-β2 treatment, displaying phenotypic changes such as loss of endothelial marker and acquisition of mesenchymal markers, which are consistent with the EndMT activation. Moreover, the PAECs phenotypic transition was probably triggered by the extracellular signal–regulated kinases 1/2 (ERK1/2) signaling pathway activation. Therefore, the anatomical origin of ECs influences their ability to undergo EndMT and the selective inhibition of the ERK pathway may suppress or reverse the progression of diseases caused or aggravated by the involvement EndMT activation.


2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Valentin Platel ◽  
Sébastien Faure ◽  
Isabelle Corre ◽  
Nicolas Clere

Cancer cells evolve in a very complex tumor microenvironment, composed of several cell types, among which the endothelial cells are the major actors of the tumor angiogenesis. Today, these cells are also characterized for their plasticity, as endothelial cells have demonstrated their potential to modify their phenotype to differentiate into mesenchymal cells through the endothelial-to-mesenchymal transition (EndoMT). This cellular plasticity is mediated by various stimuli including transforming growth factor-β (TGF-β) and is modulated dependently of experimental conditions. Recently, emerging evidences have shown that EndoMT is involved in the development and dissemination of cancer and also in cancer cell to escape from therapeutic treatment. In this review, we summarize current updates on EndoMT and its main induction pathways. In addition, we discuss the role of EndoMT in tumorigenesis, metastasis, and its potential implication in cancer therapy resistance.


2019 ◽  
Vol 99 (2) ◽  
pp. 1281-1324 ◽  
Author(s):  
Sonsoles Piera-Velazquez ◽  
Sergio A. Jimenez

Numerous studies have demonstrated that endothelial cells are capable of undergoing endothelial to mesenchymal transition (EndMT), a newly recognized type of cellular transdifferentiation. EndMT is a complex biological process in which endothelial cells adopt a mesenchymal phenotype displaying typical mesenchymal cell morphology and functions, including the acquisition of cellular motility and contractile properties. Endothelial cells undergoing EndMT lose the expression of endothelial cell-specific proteins such as CD31/platelet-endothelial cell adhesion molecule, von Willebrand factor, and vascular-endothelial cadherin and initiate the expression of mesenchymal cell-specific genes and the production of their encoded proteins including α-smooth muscle actin, extra domain A fibronectin, N-cadherin, vimentin, fibroblast specific protein-1, also known as S100A4 protein, and fibrillar type I and type III collagens. Transforming growth factor-β1 is considered the main EndMT inducer. However, EndMT involves numerous molecular and signaling pathways that are triggered and modulated by multiple and often redundant mechanisms depending on the specific cellular context and on the physiological or pathological status of the cells. EndMT participates in highly important embryonic development processes, as well as in the pathogenesis of numerous genetically determined and acquired human diseases including malignant, vascular, inflammatory, and fibrotic disorders. Despite intensive investigation, many aspects of EndMT remain to be elucidated. The identification of molecules and regulatory pathways involved in EndMT and the discovery of specific EndMT inhibitors should provide novel therapeutic approaches for various human disorders mediated by EndMT.


2017 ◽  
Vol 42 (1) ◽  
pp. 357-372 ◽  
Author(s):  
Yin Xiang ◽  
Yachen Zhang ◽  
Yong Tang ◽  
Qianhui Li

Background/Aims: Endothelial-to-mesenchymal transition (EndMT) plays significant roles under various pathological conditions including cardiovascular diseases, fibrosis, and cancer. EndMT of endothelial progenitor cells (EPCs) contributes to neointimal hyperplasia following cell therapy Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is a long non-coding RNA (lncRNA) that promotes metastasis and cancer. MicroRNA-145 (miR-145) is a tumor suppressor that has been reported to inhibit SMAD3-mediated epithelial-to-mesenchymal transition (EMT) of cancer cells. In the present study, we investigated the role of MALAT1 and miR-145 in EndMT of human circulating EPCs induced by transforming growth factor beta1 (TGF-β1). Methods: Human circulating EPCs were isolated and characterized by fluorescence-activated cell sorting (FACS). Expression levels of EndMT markers were assessed by qRT-PCR and western blotting. Alpha-smooth muscle actin (α-SMA) expression was measured by cell immunofluorescence staining. The regulatory relationship between MALAT1 and miR-145 and its target genes, TGFBR2 (TGFβ receptortype II) and SMAD3 (mothers against decapentaplegic homolog 3) was analyzed using the luciferase reporter assay. Results: We found that EndMT of EPCs induced by TGF-β1 is accompanied by increased MALAT1 expression and decreased miR-145 expression, and MALAT1 and miR-145 directly bind and reciprocally repress each other in these cells. Dual-Luciferase Reporter assay indicated that miR-145 inhibits TGF-β1-induced EndMT by directly targeting TGFBR2 and SMAD3. Conclusions: MALAT1 modulates TGF-β1-induced EndMT of EPCs through regulation of TGFBR2 and SMAD3 via miR-145. Thus, the MALAT1-miR-145-TGFBR2/SMAD3 signaling pathway plays a key role in TGF-β1-induced EndMT.


2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Zhenyuan Wei ◽  
Yang Zhao ◽  
Peichun Hsu ◽  
Shang Guo ◽  
Chi Zhang ◽  
...  

Abstract Background Heterotopic ossification (HO) can limit joint activity, causes ankylosis and impairs the function and rehabilitation of patients. Endothelial to mesenchymal transition (EndMT) plays an important role in the pathogenesis of HO, and high expression of SMAD7(Mothers Against Decapentaplegic Homolog 7) in endothelial cells can effectively reverse the TGF-β1 mediated EndMT. This article studied an appropriately engineered exosome with high biocompatibility and good targeting property to administrate SMAD7 gene therapy to inhibit the EndMT. Methods Exosomes from mouse aortic endothelial cells were cultured and harvested. DSPE-PEG and antibody CD34 were combined to exosomes to synthesize the endothelial cell targeting exosome vector (Exosome-DSPE-PEG-AbCD34). The biocompatibility, stability, targeting and cell internalization of exosome vector were tested, then the Exosome-DSPE-PEG-AbCD34 was loaded with Smad7 plasmid and administrated to MAECs to examine its therapeutic effect on EndMT of MAEC mediated by TGF-β1. Results The Exosome-DSPE-PEG-AbCD34 has no impact on MAEC cell viability at high concentration, and exosome-DSPE-PEG-AbCD34 could be stably stored at 4°C and 37°C for at least 8 days. Exosome-DSPE-PEG-AbCD34 has better targeting property to MAEC cells and can enter into the cells more effectively. The Exosome-DSPE-PEG-AbCD34-Smad7 could significantly increase the level of SMAD7, decrease the expression of TGF-β1, and effectively reverse the EndMT of MAEC mediated by TGF- β1 in MAEC cells. Conclusions The synthesized Exosome-DSPE-PEG-AbCD34-Smad7 has good biological properties and can effectively reverse the EndMT of MAEC mediated by TGF-β1. Thus, Exosome-DSPE-PEG-AbCD34-Smad7 may has the potential for the prevention and treatment of HO.


Author(s):  
Xiaodong Liang ◽  
Shuo Wu ◽  
Zilong Geng ◽  
Li Liu ◽  
Shasha Zhang ◽  
...  

Rationale: Endothelial-to-mesenchymal transition (EndMT) is a fundamental biological process in which endothelial cells lose their endothelial characteristics and acquire mesenchymal properties. EndMT contributes to physiological organ development such as valvulogenesis, and is associated with a number of deleterious pathologies such as organ fibrosis. Several signaling pathways of transforming growth factor beta (TGF-β), bone morphogenetic protein (BMP) and inflammation have been shown to regulate EndMT. However, the transcriptional and epigenetic programs governing EndMT remains largely unclarified. Objective: To identify the transcriptional or epigenetic mechanisms underlying EndMT and EndMT-associated formation of cardiac valves. Methods and Results: We identified the La ribonucleoprotein domain family member 7 (LARP7), a RNA binding protein regulating RNA polymerase II (RNAPII) pausing, was downregulated in two cytokine-induced EndMT models. LARP7 depletion with lentivirus-mediated shRNA transformed endothelial cells to mesenchymal morphology and induced the expression of the EndMT key regulator, SLUG. Specific deletion of LARP7 in the endocardium in inducible CDH5CreERT2;LARP7f/f mouse enhanced EndMT in the atrioventricular and outflow tract (OFT) cushion as revealed by lineage tracing approach. ChIP-seq analysis showed LARP7 and Tripartite Motif Containing 28 (TRIM28) which is an epigenetic repressor were colocalized at SLUG promoter. LARP7 directly interacted with TRIM28 and facilitated it loading to SLUG promoter and repressed its transcription through deacetylating the histones. More importantly, inducible knockout of LARP7 or TRIM28 in the endocardium accelerated EndMT, leading to the valvular hyperplasia, which was further aggravated by the double knockout of these two genes. Conclusions: The present study uncovers an orchestrated transcriptional and epigenetic mechanism by which LARP7 cooperates with TRIM28 to govern the EndMT and valvulogenesis.


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