The Mitochondrial Protein Mitofusin 2 Stabilizes Adherens Junctions and Suppresses Endothelial Inflammation via Modualtion of β-catenin Signaling
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE148987 | GEO | 2023/04/18
REPOSITORIES: GEO
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Project description:The vascular endothelium forms a physical barrier between blood and the surrounding tissue. Its constant exposure to haemodynamic shear stress controls endothelial barrier function which is of major importance for vascular homeostasis. The role of long non-coding RNAs (lncRNAs) in this process remains elusive. Here we identify the shear stress-induced lncRNA LASSIE (linc00520) as a stabilizer of adherens junctions (AJs) in endothelial cells (ECs), that is indispensable for normal endothelial barrier function and shear stress sensing. Silencing of LASSIE in ECs resulted in impaired cell survival, loss of cell-cell contacts and failure to align in the direction of flow. RNA affinity purification followed by mass spectrometry identified several junction proteins associated with LASSIE, including the endothelial adhesion protein PECAM-1 and intermediate filament (IF) protein nestin. Proteomic analysis of VE-cadherin-associated proteins showed that LASSIE silencing reduces VE-cadherin interaction with nestin and microtubule (MT)-associated cytoskeletal proteins. We confirmed that LASSIE silencing results in a decreased connection between VE-Cadherin and the cytoskeleton, resulting in loss of barrier function and shear stress sensing. Together, this study identifies the shear stress-induced lncRNA LASSIE as a critical link between AJs and the IF cytoskeleton, which is indispensable for normal EC junction stabilization and shear stress sensing.
2020-04-21 | GSE146110 | GEO
Project description:Blood-brain barrier (BBB) dysfunction is emerging as a key pathogenic factor in the progression of Alzheimer’s disease (AD), where increased microvascular endothelial permeability has been proposed to play an important role. However, the molecular mechanisms leading to increased brain microvascular permeability in AD are not fully understood. We observed that brain endothelial permeability in the APPswe/PS1DE9 (APP/PS1) transgenic mouse model of amyloid-beta (Ab) amyloidosis increases with aging in the areas with the greatest amyloid plaque deposition. We performed an unbiased bulk RNA-sequencing analysis of brain endothelial cells (BECs) in APP/PS1 transgenic mice. We observed that upregulation of interferon signaling gene expression pathways in BECs were among the most prominent transcriptomic signatures in the brain endothelium of APP/PS1 mice. Immunofluorescence analysis of isolated BECs from APP/PS1 mice demonstrated higher levels of the Type I interferon-stimulated gene IFIT2. Immunoblotting of APP/PS1 BECs showed downregulation of the adherens junction protein VE-cadherin. Stimulation of human brain endothelial cells with interferon-β decreased the levels of the adherens junction protein VE-cadherin as well as tight junction proteins Occludin and Claudin-5 and increased barrier leakiness. Depletion of the Type I interferon receptor in human brain endothelial cells prevented interferon-β-induced VE- cadherin downregulation and restored endothelial barrier integrity. Our study suggests that Type I interferon signaling contributes to brain endothelial dysfunction in AD.
2022-06-25 | GSE206629 | GEO
Project description:Rationale: The mechanistic foundation of vascular maturation is still largely unknown. Several human pathologies are characterized by deregulated angiogenesis and unstable blood vessels. Solid tumours, for instance, get their nourishment from newly formed structurally abnormal vessels which present wide and irregular inter-endothelial junctions. Expression and clustering of the main endothelial-specific adherens junction protein, vascular endothelial (VE)-cadherin (VEC), upregulate genes with key roles in endothelial differentiation and stability. Objective: We aim at understanding the molecular mechanisms through which VEC triggers the expression of a set of genes involved in endothelial differentiation and vascular stabilization. Methods and Results: We compared a VEC-null cell line with the same line reconstituted with VEC wild type cDNA. VEC expression and clustering upregulated endothelial-specific genes with key roles in vascular stabilization including claudin-5, Vascular Endothelial-Protein Tyrosine Phosphatase (VE-PTP) and von Willebrand factor (vWf). Mechanistically VEC exerts this effect by inhibiting Polycomb protein activity on the specific gene promoters. This is achieved by preventing nuclear translocation of FoxO1 and β-catenin, which contribute to Polycomb repressive complex-2 (PRC2) binding to promoter regions of claudin-5, VE-PTP and vWf. VE-cadherin/β-catenin complex also sequesters a core subunit of PRC2 (Ezh2) at the cell membrane, preventing its nuclear translocation. Inhibition of Ezh2/VE-cadherin association increases Ezh2 recruitment to claudin-5, VE-PTP and vWf promoters, causing gene downregulation. RNAseq comparison of VEC-null and VEC-positive cells suggested a more general role of VE-cadherin in activating endothelial genes and triggering a vascular stability-related gene expression program. In pathological angiogenesis of human ovarian carcinomas, reduced VEC expression paralleled decreased levels of Claudin-5 and VE-PTP. Conclusions: These data extend the knowledge of Polycomb-mediated regulation of gene expression to endothelial cell differentiation and vessel maturation. The identified mechanism opens novel therapeutic opportunities to modulate endothelial gene expression and induce vascular normalization through pharmacological inhibition of the Polycomb-mediated repression system. Keywords: Polycomb, endothelial cells, VE-cadherin, vessel maturation, vascular biology, vascular permeability, cell signalling, epigenetics, gene regulation. Downloaded from http://circres.ahajour Conclusions: These data extend the knowledge of Polycomb-mediated regulation of gene expression to endothelial cell differentiation and vessel maturation. The identified mechanism opens novel therapeutic opportunities to modulate endothelial gene expression and induce vascular normalization through pharmacological inhibition of the Polycomb-mediated repression system
2019-10-19 | GSE139092 | GEO
Project description:The shear stress-regulated lncRNA LASSIE interacts with junctional proteins (e.g. PECAM-1, which interacts with VE-cadherin) and influences endothelial barrier function. Here we characterize the remodeling of the VE-Cadherin complex by the lncRNA LASSIE. LASSIE silenced HUVECs were subjected to co-immunoprecipitation using an anti-VE-cadherin antibody. Differentially associated proteins were identified by Mass spectrometry. This analysis revealed a significantly decreased association of cytoskeleton-linked proteins with VE-cadherin after silencing of LASSIE. Functional assays confirmed this result and characterized LASSIE as a stabilizer of junctional complexes in endothelial cells, important for normal shear stress sensing and barrier function.
2021-09-09 | PXD018725 | Pride
Project description:In order to identify genes regulated by VE-cadherin expression, we compared a mouse VE-cadherin null cell line (VEC null) with the same line reconstituted with VE-cadherin wild type cDNA (VEC positive). The morphological and functional properties of these cell lines were described previously [Lampugnani,M.G. et al. Contact inhibition of VEGF-induced proliferation requires vascular endothelial cadherin, beta-catenin, and the phosphatase DEP-1/CD148. J. Cell Biol. 161, 793-804 (2003)]. By Affymetrix gene expression analysis we found several genes up-regulated by VE-cadherin, among which claudin-5 reached remarkably high levels. The up-regulation of these genes required not only VE-cadherin expression but also cell confluence suggesting that VE-cadherin clustering at junctions was needed.
2008-07-06 | GSE11674 | GEO
Project description:In the initial process of COVID-19, SARS-CoV-2 infects respiratory epithelial cells and then transfers to other organs via the blood vessels. It is believed that SARS-CoV-2 can pass the vascular wall by altering the endothelial barrier using an unknown mechanism. In this study, we investigated the effect of SARS-CoV-2 on the endothelial barrier using an airway-on-a-chip that mimics respiratory organs and found that SARS-CoV-2 produced from infected epithelial cells disrupts the barrier by decreasing Claudin-5 (CLDN5), a tight junction protein, and disrupting vascular endothelial cadherin (VE-cadherin)-mediated adherens junctions. Consistently, the gene and protein expression levels of CLDN5 in a COVID-19 patient’s lungs were decreased. CLDN5 overexpression or Fluvastatin treatment could rescue the SARS-CoV-2-induced respiratory endothelial barrier disruption. We therefore concluded that the downregulation of CLDN5 expression is a pivotal mechanism for SARS-CoV-2-induced endothelial barrier disruption in respiratory organs and that inducing CLDN5 expression is a novel therapeutic strategy against COVID-19.
2022-09-22 | GSE196113 | GEO
Project description:In the initial process of COVID-19, SARS-CoV-2 infects respiratory epithelial cells and then transfers to other organs via the blood vessels. It is believed that SARS-CoV-2 can pass the vascular wall by altering the endothelial barrier using an unknown mechanism. In this study, we investigated the effect of SARS-CoV-2 on the endothelial barrier using an airway-on-a-chip that mimics respiratory organs and found that SARS-CoV-2 produced from infected epithelial cells disrupts the barrier by decreasing Claudin-5 (CLDN5), a tight junction protein, and disrupting vascular endothelial cadherin (VE-cadherin)-mediated adherens junctions. Consistently, the gene and protein expression levels of CLDN5 in a COVID-19 patient’s lungs were decreased. CLDN5 overexpression or Fluvastatin treatment could rescue the SARS-CoV-2-induced respiratory endothelial barrier disruption. We therefore concluded that the downregulation of CLDN5 expression is a pivotal mechanism for SARS-CoV-2-induced endothelial barrier disruption in respiratory organs and that inducing CLDN5 expression is a novel therapeutic strategy against COVID-19.
2022-09-22 | GSE206635 | GEO
Project description:Purpose: WNT signaling activation in colorectal cancers (CRCs) occurs mainly through APC inactivation or, more uncommonly, β-catenin activation. Both processes promote β-catenin nuclear accumulation, which transcriptionally up-regulates epithelial-to-mesenchymal transition (EMT)-related genes. Experimental Design: We investigated β-catenin localization, downstream gene expression, and phenotypic alterations in HCT116 cells containing a wild-type (HCT116-WT) or mutant β-catenin allele (HCT116-MT), or parental cells with both WT and mutant alleles (HCT116-P). We then analyzed β-catenin localization and associated phenotypes in CRC tissues. Results: Wild-type β-catenin mainly localized at the cell membrane, whereas mutant showed predominantly nuclear localization; membranous, cytoplasmic, and nuclear localization was observed in HCT116-P cells. Microarray analysis revealed significant down-regulation of Claudin-7 and E-cadherin in HCT116-MT vs. HCT116-WT cells. Claudin-7 was also down-regulated in HCT116-P vs. HCT116-WT cells, although E-cadherin expression was unaffected. Altered expression of cell-cell junction-related molecules led to tight junction (TJ) impairment in HCT116-P, and dual loss of TJs and adherens junctions (AJs) in HCT116-MT. TJ loss increased migration and invasion activities of HCT116-WT, whereas AJ loss was required to further up-regulate these activities in HCT116-P. Immunohistochemistry analysis of 101 stage III CRC tissues revealed high nuclear β-catenin expression (≥30% of tumor cells) in 15 (14.9%) samples, low nuclear expression (1-29%) in 53 (52.5%) samples, and undetectable nuclear expression in 33 (32.6%) samples, with a trend toward more frequent down-regulation of Claudin-7 and E-cadherin, and increased metastasis in CRCs with high vs. low nuclear β-catenin. Conclusions: β-catenin activation and nuclear translocation induce EMT progression by modifying cell-cell junctions, and are associated with aggressive behaviors of CRCs.
2019-11-18 | GSE126845 | GEO
Project description:Vascular endothelial protein tyrosine phosphatase (VE-PTP, PTPRB) is a receptor type phosphatase that is crucial for the regulation of endothelial junctions and blood vessel development. VE-PTP regulates vascular integrity by dephosphorylating substrates which are key players in endothelial junction stability, such as the angiopoietin receptor TIE2, the endothelial adherens junction protein VE-cadherin and the vascular endothelial growth factor receptor VEGFR2. Here, we have systematically searched for novel substrates of VE-PTP in endothelial cells by utilizing two approaches. First, we studied changes in the endothelial phosphoproteome upon exposing cells to a highly VE-PTP-specific phosphatase inhibitor followed by affinity isolation and mass-spectrometric analysis of phosphorylated proteins by phosphotyrosine-specific antibodies. Second, we used a substrate trapping mutant of VE-PTP to pull down phosphorylated substrates in combination with SILAC-based quantitative mass spectrometry measurements. We identified a set of substrate candidates of VE-PTP, of which a remarkably large fraction is related to cell junctions (48/165; 29.1%). Several of those were found in both screens and displayed very high connectivity in predicted functional interaction networks. The receptor protein tyrosine kinase EPHB4 was the most prominently phosphorylated protein upon VE-PTP inhibition among those VE-PTP targets that were identified by both proteomic approaches. Further analysis revealed that EPHB4 forms a ternary complex with VE-PTP and TIE2 in endothelial cells. VE-PTP controls the phosphorylation of each of these two tyrosine kinase receptors. Despite of their simultaneous presence in a ternary complex, stimulating each of the receptors with their own specific ligand did not cross-activate the respective partner receptor. Our systematic approach has led to the identification of novel substrates of VE-PTP, of which many are relevant for the control of cellular junctions further promoting the importance of VE-PTP as a key player of junctional signalling.
2019-08-20 | PXD011940 | Pride
Project description:Background: PIM1 is a constitutively active serine-threonine kinase regulating cell survival and proliferation. Increased PIM1 expression has been correlated with cancer metastasis by facilitating migration and anti-adhesion. Endothelial cells play a pivotal role in these processes by contributing a barrier to the blood stream. Here, we investigated whether PIM1 regulates mouse aortic endothelial cell (MAEC) monolayer integrity. Methods: Pim1-/-MAEC were isolated from Pim1 knockout mice and used in trypsinization-, wound closure assays, electrical cell-substrate sensing, immunostaining, cDNA transfection and as RNA source for microarray analysis. Results: Pim1-/-MAEC displayed decreased migration, slowed cell detachment and increased electrical resistance across the endothelial monolayer. Reintroduction of Pim1- cDNA into Pim1-/-MAEC significantly restored wildtype adhesive characteristics. Pim1-/--MAEC displayed enhanced focal adhesion and adherens junction structures containing vinculin and M-NM-2-catenin, respectively. Junctional molecules such as Cadherin 13 and matrix components such as Collagen 6a3 were highly upregulated in Pim1-/- cells. Intriguingly, extracellular matrix deposited by Pim1-/- cells alone was sufficient to induce the hyperadhesive phenotype in wildtype endothelial cells. Conclusion: Loss of Pim1 induces a strong adhesive phenotype by enhancing endothelial cell-cell and cell-matrix adhesion by the deposition of a specific extracellular matrix. Targeting PIM1 function therefore might be important to promote endothelial barrier integrity. Pim-1-/- mouse aortic endothelial cells were compared to wildtype cells
2012-10-29 | E-GEOD-32059 | biostudies-arrayexpress