TNF-alpha induces endothelial cell F-actin depolymerization, new actin synthesis, and barrier dysfunction

1993 ◽  
Vol 264 (4) ◽  
pp. C894-C905 ◽  
Author(s):  
S. E. Goldblum ◽  
X. Ding ◽  
J. Campbell-Washington

Tumor necrosis factor-alpha (TNF-alpha) influences pulmonary vascular endothelial barrier function in vitro. We studied whether recombinant TNF-alpha (rTNF-alpha) regulates endothelial barrier function through actin reorganization. Postconfluent bovine pulmonary artery endothelial cell monolayers were exposed to human rTNF-alpha (1,000 U/ml) and evaluated for 1) transendothelial [14C]albumin flux, 2) F-actin organization with fluorescence microscopy, 3) F-actin quantitation by spectrofluorometry, and 4) monomeric G-actin levels by the deoxyribonuclease I inhibition assay. rTNF-alpha induced increments in [14C]albumin flux (P < 0.04) and intercellular gap formation at > or = 2-6 h. During this same time, the endothelial F-actin pool decreased (P = 0.0064), with reciprocal increases in the G-actin pool (P < 0.0001). Prior F-actin stabilization with phallicidin protected against the rTNF-alpha-induced increments in G-actin (P < 0.002) as well as changes in barrier function (P < 0.01). Prior protein synthesis inhibition enhanced the rTNF-alpha-induced decrement in F-actin (P < 0.0001), blunted the G-actin increment (P < 0.002), and increased rTNF-alpha-induced changes in endothelial barrier function (P < 0.003). Therefore, rTNF-alpha induces pulmonary vascular endothelial F-actin depolymerization, intercellular gap formation, and barrier dysfunction. rTNF-alpha also increased total actin (P < 0.02) and new actin synthesis (P < 0.002), which may be a compensatory endothelial cell response to rTNF-alpha-induced F-actin depolymerization.

2016 ◽  
Vol 64 (4) ◽  
pp. 965.3-966
Author(s):  
J Cai ◽  
J Wei ◽  
AM Jacko ◽  
J Zhao

BackgroundMaintenance of pulmonary endothelial barrier integrity is important for reducing severity of lung injury. VE-cadherin is a major component of cell–cell adherens junctions in endothelium. In response to inflammatory stimuli, VE-cadherin is tyrosine phosphorylated, resulting in dissociation with catenins, which links to f-actin. Lysophosphatidic acid (LPA) is a bioactive lysophospholipid, which regulates cell motility. LPA has been shown to increase lung epithelial barrier integrity, while it reduces endothelial barrier function. AM966 is an antagonist exhibiting an anti-fibrotic property. However, the effect of AM966 on pulmonary endothelial barrier integrity has not been well studied.Methods and ResultsTo investigate endothelial barrier integrity, electric cell-substrate sensing (ECIS) system was used to measure permeability in human lung microvascular endothelial cells (HLMVECs). Similar to the effect of LPA, AM966 increases permeability immediately in a dose dependent manner. To investigate the molecular mechanism by which regulates AM966-mediated reduction of endothelial barrier function, HLMVECs were treated with AM966, and then phosphorylation of myosin light chain (MLC) and VE-cadherin were determined by immunoblotting. AM966 increased phosphorylation of MLC and VE-cadherin. VE-cadherin and f-actin double immunostaining revealed that AM966 induces gap formation and f-actin stress fibers as well as dissociation between VE-cadherin and f-actin.ConclusionThis study reveals that AM966 induces lung endothelial barrier dysfunction, which is regulated by phosphorylation of VE-cadherin.This work was supported by the National Institutes of Health (R01GM115389 to J.Z.), American Heart Association 12SDG9050005 (J.Z.), American Lung Association Biomedical Research Grant RG350146 (J.Z.).


Author(s):  
Bo-Wen Xu ◽  
Zhi-Qiang Cheng ◽  
Xu-Ting Zhi ◽  
Xiao-Mei Yang ◽  
Zhi-Bo Yan

Abstract Endothelial barrier integrity requires recycling of VE-cadherin to adherens junctions. Both p18 and Rab11a play significant roles in VE-cadherin recycling. However, the underlying mechanism and the role of p18 in activating Rab11a have yet to be elucidated. Performing in vitro and in vivo experiments, we showed that p18 protein bound to VE-cadherin before Rab11a through its VE-cadherin-binding domain (aa 1–39). Transendothelial resistance showed that overexpression of p18 promoted the circulation of VE-cadherin to adherens junctions and the recovery of the endothelial barrier. Silencing of p18 caused endothelial barrier dysfunction and prevented Rab11a-positive recycling endosome accumulation in the perinuclear recycling compartments. Furthermore, p18 knockdown in pulmonary microvessels markedly increased vascular leakage in mice challenged with lipopolysaccharide and cecal ligation puncture. This study showed that p18 regulated the pulmonary endothelial barrier function in vitro and in vivo by regulating the binding of Rab11a to VE-cadherin and the activation of Rab11a.


2021 ◽  
Vol 19 ◽  
pp. 205873922110623
Author(s):  
Hisatake Mori ◽  
Muhammad Aminul Huq ◽  
Md. Monirul Islam ◽  
Naoshi Takeyama

Introduction: Acute respiratory response syndrome (ARDS) leads to increased permeability of the endothelial-epithelial barrier, which in turn promotes edema formation and hypoxemic respiratory failure. Although activated neutrophils are thought to play a significant role in mediating ARDS, at present the contribution of neutrophil extracellular traps (NETs) to lung endothelial barrier function is unclear. Methods: To clarify their role, we co-cultured in vitro NETs induced by phorbol myristate acetate (PMA)–activated neutrophils with lung endothelial cell monolayers and examined the barrier function of lung endothelial cells by immunofluorescence microscopy and albumin permeability in a double-chamber culture method. Results: Co-culture with stimulated neutrophils increased the albumin permeability of the human pulmonary artery endothelial cell (HPAEC) monolayer and altered cytoskeleton F-actin and vascular endothelial-cadherin in cell-cell junctions. Hyperpermeability to albumin and histological alterations were prevented by inhibition of NET formation with peptidyl arginine deiminase inhibitor or a neutrophil elastase inhibitor and were also prevented by increased degradation of NET structure with DNase. Conclusion: This in vitro experiment shows that altered HPAEC barrier function and increased albumin permeability are caused by the direct effect of PMA-induced NETs and their components. NET formation may be involved in the increased vascular permeability of the lung, which is a common feature in ARDS of various etiologies. These insights may help generate novel approaches for medical interventions.


2005 ◽  
Vol 79 (16) ◽  
pp. 10442-10450 ◽  
Author(s):  
Victoria M. Wahl-Jensen ◽  
Tatiana A. Afanasieva ◽  
Jochen Seebach ◽  
Ute Ströher ◽  
Heinz Feldmann ◽  
...  

ABSTRACT Ebola virus causes severe hemorrhagic fever with high mortality rates in humans and nonhuman primates. Vascular instability and dysregulation are disease-decisive symptoms during severe infection. While the transmembrane glycoprotein GP1,2 has been shown to cause endothelial cell destruction, the role of the soluble glycoproteins in pathogenesis is largely unknown; however, they are hypothesized to be of biological relevance in terms of target cell activation and/or increase of endothelial permeability. Here we show that virus-like particles (VLPs) consisting of the Ebola virus matrix protein VP40 and GP1,2 were able to activate endothelial cells and induce a decrease in barrier function as determined by impedance spectroscopy and hydraulic conductivity measurements. In contrast, the soluble glycoproteins sGP and Δ-peptide did not activate endothelial cells or change the endothelial barrier function. The VLP-induced decrease in barrier function was further enhanced by the cytokine tumor necrosis factor alpha (TNF-α), which is known to induce a long-lasting decrease in endothelial cell barrier function and is hypothesized to play a key role in Ebola virus pathogenesis. Surprisingly, sGP, but not Δ-peptide, induced a recovery of endothelial barrier function following treatment with TNF-α. Our results demonstrate that Ebola virus GP1,2 in its particle-associated form mediates endothelial cell activation and a decrease in endothelial cell barrier function. Furthermore, sGP, the major soluble glycoprotein of Ebola virus, seems to possess an anti-inflammatory role by protecting the endothelial cell barrier function.


2010 ◽  
Vol 103 (01) ◽  
pp. 40-55 ◽  
Author(s):  
Cora Beckers ◽  
Victor van Hinsbergh ◽  
Geerten van Nieuw Amerongen

SummaryIn the past decade understanding of the role of the Rho GTPases RhoA, Rac1 and Cdc42 has been developed from regulatory proteins that regulate specific actin cytoskeletal structures – stress fibers, lamellipodia and filopodia – to complex integrators of cytoskeletal structures that can exert multiple functions depending on the cellular context. Fundamental to these functions are three-dimensional complexes between the individual Rho GTPases, their specific activators (GEFs) and inhibitors (GDIs and GAPs), which greatly outnumber the Rho GTPases themselves, and additional regulatory proteins. By this complexity of regulation different vasoactive mediators can induce various cytoskeletal structures that enable the endothelial cell (EC) to respond adequately. In this review we have focused on this complexity and the consequences of Rho GTPase regulation for endothelial barrier function. The permeability inducers thrombin and VEGF are presented as examples of G-protein coupled receptor- and tyrosine kinase receptormediated Rho GTPase activation, respectively. These mediators induce complex but markedly different networks of activators, inhibitors and effectors of Rho GTPases, which alter the endothelial barrier function. An interesting feature in this regulation is that Rho GTPases often have both barrier-protecting and barrier-disturbing functions. While Rac1 enforces the endothelial junctions, it becomes part of a barrier-disturbing mechanism as activator of reactive oxygen species generating NADPH oxidase. Similarly RhoA is protective under basal conditions, but becomes involved in barrier dysfunction after activation of ECs by thrombin. The challenge and promise lies in unfolding this complex regulation, as this will provide leads for new therapeutic opportunities.


2019 ◽  
Vol 6 ◽  
Author(s):  
Quan-Yong Huang ◽  
Yu-Chuan Chen ◽  
Shui-Ping Liu

Background: Alcohol abuse is involved in the pathogenesis of multiple organ disorders; the underlying mechanism is incompletely understood. The ubiquitin editing enzyme A20 is involved in regulating activities in the cell. Suppression of A20 is suggested as one factor in the initiation of  inflammation. This study investigates the mechanism by which chronic alcohol consumption modulates the levels of ubiquitin editing enzyme A20 in macrophages and further contributes to induce endothelial barrier dysfunction in the lung. Methods: Mice were gavage-fed with 40% alcohol daily for 0- 3 weeks. Airway macrophages were collected by lung lavage. Expression of ubiquitin editing enzyme A20 in isolated macrophages was assessed at both mRNA and protein levels. The endothelial barrier function of the lung was evaluated by the Evans blue method. Results: Mice treated with alcohol for 3 weeks showed an increase in cell infiltration in the lung in response to exposure to peptidoglycan; over 80% of the infiltrated cells were macrophages. Furthermore, we observed that A20 level was suppressed in macrophages of mice treated with alcohol; the levels of tumor necrosis factor, interleukin-6 and nuclear factor kappa B in macrophage were increased. In addition, the endothelial barrier function of the lung was compromised, showing excessive infiltration of Evans blue in the lung indicating lung edema. Pretreatment with synthesized A20 inhibited alcohol-induced lung endothelial barrier dysfunction. Conclusions: We conclude that chronic alcohol ingestion disturbs the endothelial barrier function in the lung by modulating macrophage properties. Increase in A20 in the cell may have potential for the treatment of inflammatory disorders.


1995 ◽  
Vol 73 (04) ◽  
pp. 706-712 ◽  
Author(s):  
P G Bannon ◽  
Mi-Jurng Kim ◽  
R T Dean ◽  
J Dawes

SummaryGlycosaminoglycans (GAGs) are an important component of endothelial barrier function. Early passage human umbilical vein endothelial cells were grown to confluence on transparent micropore filters and barrier function assessed as transendothelial electrical resistance (TEER) and permeability to albumin and sucrose. Unfractionated heparin and the LMW heparin Clexane decreased endothelial permeability to both sucrose and albumin and increased TEER. Chondroitin 6-sulphate also augmented barrier function, but other GAGs had no effect. Interleukin-1 increased permeability to albumin and sucrose and decreased TEER. Although heparin attenuated the effect of IL-1 on TEER and sucrose permeability, it could not restore the barrier to albumin transfer. Denuded endothelial matrix presented a negligible barrier, which was not enhanced by heparin. When sulphation of endogenous GAGs was inhibited by chlorate, barrier function was compromised and was not restored by exogenous heparin. Thus heparin enhances the barrier function of resting endothelium, but cannot completely overcome the increased permeability resulting from exposure to IL-1 or substitute for endogenous GAGs.


Sign in / Sign up

Export Citation Format

Share Document