scholarly journals Phosphorylated cingulin localises GEF-H1 at tight junctions to protect vascular barriers in blood endothelial cells

2021 ◽  
Author(s):  
Silvio Holzner ◽  
Sophie Bromberger ◽  
Judith Wenzina ◽  
Karin Neumüller ◽  
Tina-Maria Holper ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Tight Junctions ◽  
Barrier Function ◽  
Inflammatory Diseases ◽  
Adaptor Protein ◽  
Cell Junctions ◽  
Nucleotide Exchange ◽  
Vascular Leak ◽  
Myosin Light Chain 2 ◽  
Nucleotide Exchange Factor

Cell-cell junctions of blood endothelial cells are critical barriers in inflammatory diseases. Endothelial tight junctions (TJs) control barrier function, and the cytoplasmic adaptor protein cingulin connects TJs to signalling pathways. However, local events at TJs during inflammation are largely unknown. In this study, we investigate the local response of TJ adaptor protein cingulin and its interaction with Rho guanine nucleotide exchange factor H1 (GEF-H1) upon vascular barrier disruption to find a new approach to counteract vascular leak. Based on transendothelial-electrical-resistance (TEER) measurements, cingulin strengthened barrier integrity upon stimulation with histamine, thrombin, and VEGF. Cingulin also attenuated myosin light chain 2 (MLC2) phosphorylation by localising GEF-H1 to cell junctions. Using cingulin phosphomutants, we verified that the phosphorylation of the cingulin head domain is required for its protective effect. Increased colocalisation of GEF-H1 and cingulin was observed in the vessels of vasculitis patients compared to those in healthy skin. Our findings demonstrate that cingulin can counteract vascular leak at TJs, suggesting the existence of a novel mechanism in blood endothelial cells that protects barrier function in diseases.

Abstract 546: L-NAME Attenuates the Cardiotonic Steroids-induced Monolayer Permeability in Lymphatic Endothelial Cells

Hypertension ◽  
2013 ◽  
Vol 62 (suppl_1) ◽  
Author(s):  
Juan Castor ◽  
Darijana Horvat ◽  
Walter E Cromer ◽  
Thomas J Kuehl ◽  
David C Zawieja ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Protein Expression ◽  
Tight Junctions ◽  
Cell Monolayer ◽  
Hypertensive Disorder ◽  
Lymphatic Endothelial Cells ◽  
Vascular Leak Syndrome ◽  
Vascular Leak ◽  
Monolayer Permeability

Objective: Preeclampsia (preE) is a hypertensive disorder unique to pregnancy. Cardiotonic steroids (CTS) such as marinobufagenin (MBG), cinobufotalin (CINO), and ouabain (OUB) are Na + /K + ATPase inhibitors. MBG is elevated in a rat model and patients with preE. MBG causes a vascular leak syndrome in vivo and increases endothelial cell monolayer permeability. Edema is a common syndrome of preE. To assess whether CTS are involved in the leakage of lymphatic endothelial cells (LECs) lining during preE, we evaluated the effect of these CTS on monolayer permeability of LECs in culture. Methods: LECs were isolated from a rat mesenteric collecting lymphatic vessel. The cells were treated with DMSO (vehicle), MBG, CINO, or OUB (1, 10 or 100 nM). Some LECs were pretreated with L-NAME (N-Nitro-L-Arginine Methyl Ester) at a concentration of 1μM before treatment with 100 nM MBG or CINO. Monolayer permeability of CTS-induced LECs was measured by using a fluorescent dye that was quantified on a fluorescence plate reader. The expression of β-catenin and VE-cadherin in the CTS-treated LECs was measured by immunofluorescence. Western blot was performed to measure β-catenin, VE-cadherin, and LYVE-1 protein levels. Statistical comparisons were performed using analysis of variance with Dunnett's post hoc tests. Results: MBG (≥ 1 nM, p<0.05) and CINO (≥ 10 nM, p<0.05) significantly increased the monolayer permeability of LECs compared to DMSO while OUB had no effect. Pretreatment of LECs with 1μM L-NAME attenuated the monolayer permeability of LECs treated with either 100 nM of MBG (p<0.05) or 100 nM of CINO (p<0.05). The β-catenin protein expression in LECs was downregulated by both MBG (p<0.05) and CINO (p<0.05) treatment. However, CTS did not cause any disruption of the LECs tight junctions. CINO (p<0.05) downregulated the VE-cadherin and LYVE-1 protein expression, but MBG did not. Conclusions: We have demonstrated that bufadienolides, MBG and CINO, caused an increase in the monolayer permeability of LECs which was attenuated by L-NAME pretreatment. Moreover, the β-catenin protein expression was downregulated by MBG and CINO treatment with no significant effect on tight junctions. These data suggest that CTS may be involved in the vascular leak syndrome in the LEC lining in preE.

Modulation of tight junction structure in blood-brain barrier endothelial cells. Effects of tissue culture, second messengers and cocultured astrocytes

1994 ◽  
Vol 107 (5) ◽  
pp. 1347-1357 ◽  
Author(s):  
H. Wolburg ◽  
J. Neuhaus ◽  
U. Kniesel ◽  
B. Krauss ◽  
E.M. Schmid ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Tight Junction ◽  
Tight Junctions ◽  
Blood Brain Barrier ◽  
Barrier Function ◽  
Primary Cultures ◽  
Brain Barrier ◽  
Brain Endothelial Cells ◽  
Blood Brain ◽  
Camp Levels

Tight junctions between endothelial cells of brain capillaries are the most important structural elements of the blood-brain barrier. Cultured brain endothelial cells are known to loose tight junction-dependent blood-brain barrier characteristics such as macromolecular impermeability and high electrical resistance. We have directly analyzed the structure and function of tight junctions in primary cultures of bovine brain endothelial cells using quantitative freeze-fracture electron microscopy, and ion and inulin permeability. The complexity of tight junctions, defined as the number of branch points per unit length of tight junctional strands, decreased 5 hours after culture but thereafter remained almost constant. In contrast, the association of tight junction particles with the cytoplasmic leaflet of the endothelial membrane bilayer (P-face) decreased continuously with a major drop between 16 hours and 24 hours. The complexity of tight junctions could be increased by elevation of intracellular cAMP levels while phorbol esters had the opposite effect. On the other hand, the P-face association of tight junction particles was enhanced by elevation of cAMP levels and by coculture of endothelial cells with astrocytes or exposure to astrocyte-conditioned medium. The latter effect on P-face association was induced by astrocytes but not fibroblasts. Elevation of cAMP levels together with astrocyte-conditioned medium synergistically increased transendothelial electrical resistance and decreased inulin permeability of primary cultures, thus confirming the effects on tight junction structure and barrier function. P-face association of tight junction particles in brain endothelial cells may therefore be a critical feature of blood-brain barrier function that can be specifically modulated by astrocytes and cAMP levels. Our results suggest an important functional role for the cytoplasmic anchorage of tight junction particles for brain endothelial barrier function in particular and probably paracellular permeability in general.

scholarly journals MYADM controls endothelial barrier function through ERM-dependent regulation of ICAM-1 expression

2013 ◽  
Vol 24 (4) ◽  
pp. 483-494 ◽  
Author(s):  
Juan F. Aranda ◽  
Natalia Reglero-Real ◽  
Beatriz Marcos-Ramiro ◽  
Ana Ruiz-Sáenz ◽  
Laura Fernández-Martín ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Plasma Membrane ◽  
Inflammatory Response ◽  
Barrier Function ◽  
Leukocyte Adhesion ◽  
Cell Junctions ◽  
Membrane Domains ◽  
Filamentous Actin ◽  
Cytokine Tumor Necrosis Factor ◽  
Factor Α

The endothelium maintains a barrier between blood and tissue that becomes more permeable during inflammation. Membrane rafts are ordered assemblies of cholesterol, glycolipids, and proteins that modulate proinflammatory cell signaling and barrier function. In epithelial cells, the MAL family members MAL, MAL2, and myeloid-associated differentiation marker (MYADM) regulate the function and dynamics of ordered membrane domains. We analyzed the expression of these three proteins in human endothelial cells and found that only MYADM is expressed. MYADM was confined in ordered domains at the plasma membrane, where it partially colocalized with filamentous actin and cell–cell junctions. Small interfering RNA (siRNA)-mediated MYADM knockdown increased permeability, ICAM-1 expression, and leukocyte adhesion, all of which are features of an inflammatory response. Barrier function decrease in MYADM-silenced cells was dependent on ICAM-1 expression. Membrane domains and the underlying actin cytoskeleton can regulate each other and are connected by ezrin, radixin, and moesin (ERM) proteins. In endothelial cells, MYADM knockdown induced ERM activation. Triple-ERM knockdown partially inhibited ICAM-1 increase induced by MYADM siRNA. Importantly, ERM knockdown also reduced ICAM-1 expression in response to the proinflammatory cytokine tumor necrosis factor-α. MYADM therefore regulates the connection between the plasma membrane and the cortical cytoskeleton and so can control the endothelial inflammatory response.

scholarly journals In Vitro Formation of Recycling Vesicles from Endosomes Requires Adaptor Protein-1/Clathrin and Is Regulated by Rab4 and the Connector Rabaptin-5

2004 ◽  
Vol 15 (11) ◽  
pp. 4990-5000 ◽  
Author(s):  
Adriana Pagano ◽  
Pascal Crottet ◽  
Cristina Prescianotto-Baschong ◽  
Martin Spiess
Keyword(s):  
Brefeldin A ◽  
Adaptor Protein ◽  
Adaptor Proteins ◽  
Vesicle Formation ◽  
Dependent Manner ◽  
Nucleotide Exchange ◽  
Vitro Assay ◽  
Guanine Nucleotide Exchange ◽  
Nucleotide Exchange Factor

The involvement of clathrin and associated adaptor proteins in receptor recycling from endosomes back to the plasma membrane is controversial. We have used an in vitro assay to identify the molecular requirements for the formation of recycling vesicles. Cells expressing the asialoglycoprotein receptor H1, a typical recycling receptor, were surface biotinylated and then allowed to endocytose for 10 min. After stripping away surface-biotin, the cells were permeabilized and the cytosol washed away. In a temperature-, cytosol-, and nucleotide-dependent manner, the formation of sealed vesicles containing biotinylated H1 could be reconstituted. Vesicle formation was strongly inhibited upon immunodepletion of adaptor protein (AP)-1, but not of AP-2 or AP-3, from the cytosol, and was restored by readdition of purified AP-1. Vesicle formation was stimulated by supplemented clathrin, but inhibited by brefeldin A, consistent with the involvement of ARF1 and a brefeldin-sensitive guanine nucleotide exchange factor. The GTPase rab4, but not rab5, was required to generate endosome-derived vesicles. Depletion of rabaptin-5/rabex-5, a known interactor of both rab4 and γ-adaptin, stimulated and addition of the purified protein strongly inhibited vesicle production. The results indicate that recycling is mediated by AP-1/clathrin-coated vesicles and regulated by rab4 and rabaptin-5/rabex-5.

Possible involvement of gap junctions in the barrier function of tight junctions of brain and lung endothelial cells

2006 ◽  
Vol 208 (1) ◽  
pp. 123-132 ◽  
Author(s):  
Kunihiko Nagasawa ◽  
Hideki Chiba ◽  
Hiroki Fujita ◽  
Takashi Kojima ◽  
Tsuyoshi Saito ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Gap Junctions ◽  
Tight Junctions ◽  
Barrier Function ◽  
Lung Endothelial Cells

scholarly journals INAVA-ARNO complexes bridge mucosal barrier function with inflammatory signaling

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Phi Luong ◽  
Matija Hedl ◽  
Jie Yan ◽  
Tao Zuo ◽  
Tian-Min Fu ◽  
...  
Keyword(s):  
Cross Talk ◽  
Barrier Function ◽  
Disease Risk ◽  
Cell Junctions ◽  
Actin Dynamics ◽  
Mucosal Barrier ◽  
Nucleotide Exchange ◽  
Inflammatory Signaling ◽  
Epithelial Barrier Function ◽  
Mucosal Barrier Function

Homeostasis at mucosal surfaces requires cross-talk between the environment and barrier epithelial cells. Disruption of barrier function typifies mucosal disease. Here we elucidate a bifunctional role in coordinating this cross-talk for the inflammatory bowel disease risk-gene INAVA. Both activities require INAVA’s DUF3338 domain (renamed CUPID). CUPID stably binds the cytohesin ARF-GEF ARNO to effect lateral membrane F-actin assembly underlying cell-cell junctions and barrier function. Unexpectedly, when bound to CUPID, ARNO affects F-actin dynamics in the absence of its canonical activity as a guanine nucleotide-exchange factor. Upon exposure to IL-1β, INAVA relocates to form cytosolic puncta, where CUPID amplifies TRAF6-dependent polyubiquitination and inflammatory signaling. In this case, ARNO binding to CUPID negatively-regulates polyubiquitination and the inflammatory response. INAVA and ARNO act similarly in primary human macrophages responding to IL-1β and to NOD2 agonists. Thus, INAVA-CUPID exhibits dual functions, coordinated directly by ARNO, that bridge epithelial barrier function with extracellular signals and inflammation.

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