The EMT transcription factor Snai1 maintains myocardial wall integrity by repressing intermediate filament gene expression

The transcription factor Snai1, a well-known regulator of epithelial-to-mesenchymal transition, has been implicated in early cardiac morphogenesis as well as in cardiac valve formation. However, a role for Snai1 in regulating other aspects of cardiac morphogenesis has not been reported. Using genetic, transcriptomic, and chimeric analyses in zebrafish, we find that Snai1b is required in cardiomyocytes for myocardial wall integrity. Loss of snai1b increases the frequency of cardiomyocyte extrusion away from the cardiac lumen. Extruding cardiomyocytes exhibit increased actomyosin contractility basally as revealed by enrichment of p-myosin and α-catenin epitope α-18, as well as disrupted intercellular junctions. Transcriptomic analysis of wild-type and snai1b mutant hearts revealed the dysregulation of intermediate filament genes, including desmin b (desmb) upregulation. Cardiomyocyte-specific desmb overexpression caused increased cardiomyocyte extrusion, recapitulating the snai1b mutant phenotype. Altogether, these results indicate that Snai1 maintains the integrity of the myocardial epithelium, at least in part by repressing desmb expression.

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The EMT transcription factor Snai1 maintains myocardial wall integrity by repressing intermediate filament gene expression

10.1101/2020.12.15.422833 ◽

2020 ◽

Author(s):

Alessandra Gentile ◽

Anabela Y.R. Bensimon-Brito ◽

Rashmi Priya ◽

Hans-Martin Maischein ◽

Janett Piesker ◽

...

Keyword(s):

Gene Expression ◽

Transcription Factor ◽

Intermediate Filament ◽

Epithelial To Mesenchymal Transition ◽

Cardiac Development ◽

Cardiac Contractility ◽

Wild Type ◽

Mesenchymal Transition ◽

Myocardial Wall

The zinc finger transcription factor Snai1 is a well-known regulator of epithelial-to-mesenchymal transition (EMT)1, 2; it is required for mesoderm ingression in flies3 and neural crest delamination in vertebrates4. During cardiac development, Snai1-regulated EMT is necessary for myocardial precursor migration and valve formation5, 6. However, a role for Snai1 in maturing cardiomyocytes (CMs) has not been reported. Here, using genetic, transcriptomic and chimeric analyses in zebrafish, we find that Snai1b is required for myocardial wall integrity. Global loss of snai1b leads to the extrusion of CMs away from the cardiac lumen, a process we show is dependent on cardiac contractility. Examining CM junctions in snai1b mutants, we observed that N-cadherin localization was compromised, thereby likely weakening cell-cell adhesion. In addition, extruding CMs exhibit increased actomyosin contractility basally, as revealed by the specific enrichment of canonical markers of actomyosin tension - phosphorylated myosin light chain (active myosin) and the α-catenin epitope α-18. By comparing the transcriptome of wild-type and snai1b mutant hearts at early stages of CM extrusion, we found the dysregulation of intermediate filament genes in mutants including the upregulation of desmin b. We tested the role of desmin b in myocardial wall integrity and found that CM-specific desmin b overexpression led to CM extrusion, recapitulating the snai1b mutant phenotype. Altogether, these results indicate that Snai1 is a critical regulator of intermediate filament gene expression in CMs, and that it maintains the integrity of the myocardial epithelium during embryogenesis, at least in part by repressing desmin b expression.

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Molecular regulation of Snai2 in development and disease

Journal of Cell Science ◽

10.1242/jcs.235127 ◽

2019 ◽

Vol 132 (23) ◽

Author(s):

Wenhui Zhou ◽

Kayla M. Gross ◽

Charlotte Kuperwasser

Keyword(s):

Transcription Factor ◽

Cell Biology ◽

Molecular Mechanisms ◽

Epithelial To Mesenchymal Transition ◽

Zinc Finger Protein ◽

Main Role ◽

Biological Processes ◽

Developmental Defects ◽

Mesenchymal Transition ◽

Damage Repair

ABSTRACT The transcription factor Snai2, encoded by the SNAI2 gene, is an evolutionarily conserved C2H2 zinc finger protein that orchestrates biological processes critical to tissue development and tumorigenesis. Initially characterized as a prototypical epithelial-to-mesenchymal transition (EMT) transcription factor, Snai2 has been shown more recently to participate in a wider variety of biological processes, including tumor metastasis, stem and/or progenitor cell biology, cellular differentiation, vascular remodeling and DNA damage repair. The main role of Snai2 in controlling such processes involves facilitating the epigenetic regulation of transcriptional programs, and, as such, its dysregulation manifests in developmental defects, disruption of tissue homeostasis, and other disease conditions. Here, we discuss our current understanding of the molecular mechanisms regulating Snai2 expression, abundance and activity. In addition, we outline how these mechanisms contribute to disease phenotypes or how they may impact rational therapeutic targeting of Snai2 dysregulation in human disease.

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Anti-Cancer Effects of Glaucarubinone in the Hepatocellular Carcinoma Cell Line Huh7 via Regulation of the Epithelial-To-Mesenchymal Transition-Associated Transcription Factor Twist1

International Journal of Molecular Sciences ◽

10.3390/ijms22041700 ◽

2021 ◽

Vol 22 (4) ◽

pp. 1700

Author(s):

Jihye Seo ◽

Jain Ha ◽

Eunjeong Kang ◽

Haelim Yoon ◽

Sewoong Lee ◽

...

Keyword(s):

Hepatocellular Carcinoma ◽

Wound Healing ◽

Transcription Factor ◽

Cell Migration ◽

Cell Line ◽

Intracellular Signaling ◽

Epithelial To Mesenchymal Transition ◽

Mesenchymal Transition ◽

Huh7 Cells ◽

Anti Cancer

Hepatocellular carcinoma (HCC), the most common type of liver cancer, is a leading cause of cancer-related deaths. As HCC has a high mortality rate and its incidence is increasing worldwide, understanding and treating HCC are crucial for resolving major public health concerns. In the present study, wound healing screening assays were performed using natural product libraries to identify natural chemicals that can inhibit cancer cell migration. Glaucarubinone (GCB) showed a high potential for inhibiting cell migration. The anti-cancer effects of GCB were evaluated using the HCC cell line, Huh7. GCB showed anti-cancer effects, as verified by wound healing, cell migration, invasion, colony formation, and three-dimensional spheroid invasion assays. In addition, cells treated with GCB showed suppressed matrix metalloproteinase activities. Immunoblotting analyses of intracellular signaling pathways revealed that GCB regulated the levels of Twist1, a crucial transcription factor associated with epithelial-to-mesenchymal transition, and mitogen-activated protein kinase. The invasive ability of cancer cells was found to be decreased by the regulation of Twist1 protein levels. Furthermore, GCB downregulated phosphorylation of extracellular signal-regulated kinase. These results indicate that GCB exhibits anti-metastatic properties in Huh7 cells, suggesting that it could be used to treat HCC.

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The flow responsive transcription factor Klf2 is required for myocardial wall integrity by modulating Fgf signaling

eLife ◽

10.7554/elife.38889 ◽

2018 ◽

Vol 7 ◽

Cited By ~ 17

Author(s):

Seyed Javad Rasouli ◽

Mohamed El-Brolosy ◽

Ayele Taddese Tsedeke ◽

Anabela Bensimon-Brito ◽

Parisa Ghanbari ◽

...

Keyword(s):

Transcription Factor ◽

Cardiac Contractility ◽

Cardiovascular Development ◽

Fgf Signaling ◽

Wild Type ◽

Complex Interplay ◽

Exact Role ◽

Cardiac Tissues ◽

Myocardial Wall ◽

Apical Side

Complex interplay between cardiac tissues is crucial for their integrity. The flow responsive transcription factor KLF2, which is expressed in the endocardium, is vital for cardiovascular development but its exact role remains to be defined. To this end, we mutated both klf2 paralogues in zebrafish, and while single mutants exhibit no obvious phenotype, double mutants display a novel phenotype of cardiomyocyte extrusion towards the abluminal side. This extrusion requires cardiac contractility and correlates with the mislocalization of N-cadherin from the lateral to the apical side of cardiomyocytes. Transgenic rescue data show that klf2 expression in endothelium, but not myocardium, prevents this cardiomyocyte extrusion phenotype. Transcriptome analysis of klf2 mutant hearts reveals that Fgf signaling is affected, and accordingly, we find that inhibition of Fgf signaling in wild-type animals can lead to abluminal cardiomyocyte extrusion. These studies provide new insights into how Klf2 regulates cardiovascular development and specifically myocardial wall integrity.

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MicroRNA-29a Suppresses CD36 to Ameliorate High Fat Diet-Induced Steatohepatitis and Liver Fibrosis in Mice

Cells ◽

10.3390/cells8101298 ◽

2019 ◽

Vol 8 (10) ◽

pp. 1298 ◽

Cited By ~ 8

Author(s):

Hung-Yu Lin ◽

Feng-Sheng Wang ◽

Ya-Ling Yang ◽

Ying-Hsien Huang

Keyword(s):

Transcription Factor ◽

Liver Fibrosis ◽

High Fat Diet ◽

Critical Role ◽

Luciferase Reporter ◽

Hepatic Tissue ◽

Wild Type ◽

High Fat ◽

Alcoholic Fatty Liver ◽

Mesenchymal Transition

MicroRNA-29 (miR-29) has been shown to play a critical role in reducing inflammation and fibrosis following liver injury. Non-alcoholic fatty liver disease (NAFLD) occurs when fat is deposited (steatosis) in the liver due to causes other than excessive alcohol use and is associated with liver fibrosis. In this study, we asked whether miR-29a could reduce experimental high fat diet (HFD)-induced obesity and liver fibrosis in mice. We performed systematical expression analyses of miR-29a transgenic mice (miR-29aTg mice) and wild-type littermates subjected to HFD-induced NAFLD. The results demonstrated that increased miR-29a not only alleviated HFD-induced body weight gain but also subcutaneous, visceral, and intestinal fat accumulation and hepatocellular steatosis in mice. Furthermore, hepatic tissue in the miR-29aTg mice displayed a weak fibrotic matrix concomitant with low fibrotic collagen1α1 expression within the affected tissues compared to the wild-type (WT) mice fed the HFD diet. Increased miR-29a signaling also resulted in the downregulation of expression of the epithelial mesenchymal transition-executing transcription factor snail, mesenchymal markers vimentin, and such pro-inflammation markers as il6 and mcp1 within the liver tissue. Meanwhile, miR-29aTg-HFD mice exhibited significantly lower levels of peroxisome proliferator-activated receptor γ (PPARγ), mitochondrial transcription factor A TFAM, and mitochondria DNA content in the liver than the WT-HFD mice. An in vitro luciferase reporter assay further confirmed that miR-29a mimic transfection reduced fatty acid translocase CD36 expression in HepG2 cells. Conclusion: Our data provide new insights that miR-29a can improve HDF-induced obesity, hepatocellular steatosis, and fibrosis, as well as highlight the role of miR-29a in regulation of NAFLD.

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Interplay among SNAIL Transcription Factor, MicroRNAs, Long Non-Coding RNAs, and Circular RNAs in the Regulation of Tumor Growth and Metastasis

Cancers ◽

10.3390/cancers12010209 ◽

2020 ◽

Vol 12 (1) ◽

pp. 209 ◽

Cited By ~ 3

Author(s):

Klaudia Skrzypek ◽

Marcin Majka

Keyword(s):

Transcription Factor ◽

Tumor Growth ◽

Epithelial To Mesenchymal Transition ◽

Cell Metabolism ◽

Circular Rnas ◽

Mesenchymal Transition ◽

Expression Of Genes ◽

Non Coding Rnas ◽

Tumor Growth And Metastasis ◽

Novel Therapeutic Strategies

SNAIL (SNAI1) is a zinc finger transcription factor that binds to E-box sequences and regulates the expression of genes. It usually acts as a gene repressor, but it may also activate the expression of genes. SNAIL plays a key role in the regulation of epithelial to mesenchymal transition, which is the main mechanism responsible for the progression and metastasis of epithelial tumors. Nevertheless, it also regulates different processes that are responsible for tumor growth, such as the activity of cancer stem cells, the control of cell metabolism, and the regulation of differentiation. Different proteins and microRNAs may regulate the SNAIL level, and SNAIL may be an important regulator of microRNA expression as well. The interplay among SNAIL, microRNAs, long non-coding RNAs, and circular RNAs is a key event in the regulation of tumor growth and metastasis. This review for the first time discusses different types of regulation between SNAIL and non-coding RNAs with a focus on feedback loops and the role of competitive RNA. Understanding these mechanisms may help develop novel therapeutic strategies against cancer based on microRNAs.

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CD47-SIRPα Signaling Induces Epithelial-Mesenchymal Transition and Cancer Stemness and Links to a Poor Prognosis in Patients with Oral Squamous Cell Carcinoma

Cells ◽

10.3390/cells8121658 ◽

2019 ◽

Vol 8 (12) ◽

pp. 1658 ◽

Cited By ~ 5

Author(s):

Shin Pai ◽

Oluwaseun Adebayo Bamodu ◽

Yen-Kuang Lin ◽

Chun-Shu Lin ◽

Pei-Yi Chu ◽

...

Keyword(s):

Squamous Cell Carcinoma ◽

Transcription Factor ◽

Oral Squamous Cell Carcinoma ◽

Cell Carcinoma ◽

Squamous Cell ◽

Epithelial To Mesenchymal Transition ◽

Epithelial Mesenchymal Transition ◽

Therapy Resistance ◽

Cellular Migration ◽

Mesenchymal Transition

Background: Oral squamous cell carcinoma (OSCC), with high mortality rates, is one of the most diagnosed head and neck cancers. Epithelial-to-mesenchymal transition (EMT) and the generation of cancer stem cells (CSCs) are two keys for therapy-resistance, relapse, and distant metastasis. Accumulating evidence indicates that aberrantly expressed cluster of differentiation (CD)47 is associated with cell-death evasion and metastasis; however, the role of CD47 in the generation of CSCs in OSCC is not clear. Methods: We investigated the functional roles of CD47 in OSCC cell lines SAS, TW2.6, HSC-3, and FaDu using the bioinformatics approach, immunoblotting, immunofluorescence staining, and assays for cellular migration, invasion, colony, and orosphere formation, as well as radiosensitivity. Results: We demonstrated increased expression of CD47 in OSCC patients was associated with an estimated poorly survival disadvantage (p = 0.0391) and positively correlated with the expression of pluripotency factors. Silencing CD47 significantly suppressed cell viability and orosphere formation, accompanied by a downregulated expression of CD133, SRY-Box transcription factor 2 (SOX2), octamer-binding transcription factor 4 (OCT4), and c-Myc. In addition, CD47-silenced OSCC cells showed reduced EMT, migration, and clonogenicity reflected by increased E-cadherin and decreased vimentin, Slug, Snail, and N-cadherin expression. Conclusion: Of therapeutic relevance, CD47 knockdown enhanced the anti-OSCC effect of radiotherapy. Collectively, we showed an increased CD47 expression promoted the generation of CSCs and malignant OSCC phenotypes. Silencing CD47, in combination with radiation, could provide an alternative and improved therapeutic efficacy for OSCC patients.

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