Mediation of endothelial injury following neutrophil adherence to extracellular matrix

1993 ◽  
Vol 264 (4) ◽  
pp. L401-L405 ◽  
Author(s):  
R. A. Kaslovsky ◽  
L. Lai ◽  
K. Parker ◽  
A. B. Malik

Since polymorphonuclear leukocytes (PMN) rapidly migrate across the endothelial barrier and attach to extracellular matrix components, we tested the hypothesis that adhesion of PMN to matrix proteins can mediate endothelial injury following PMN activation. Studies were made using gelatin- and fibronectin-coated polycarbonate microporous filters (10 microns thick) on which confluent monolayers of bovine pulmonary microvessel endothelial cells were grown. PMN were layered either directly onto endothelial cells (at a ratio of 10:1) (“upright system”) or onto gelatin- and fibronectin-coated filters with the endothelial monolayer grown on the underside of the filter without contact between PMN and endothelial cells (“inverted system”). PMN were activated with phorbol 12-myristate 13-acetate (PMA; 5 x 10(-9) M) in both systems. PMN activation increased endothelial permeability to 125I-labeled albumin in upright as well as inverted systems. Pretreatment of PMN with anti-CD18 monoclonal antibodies IB4 or R15.7, which inhibited PMN adherence to matrix constituents as well as to endothelial cells, prevented the permeability increase in both configurations. This effect of anti-CD18 monoclonal antibodies (mAbs) was not ascribed to a reduction in PMN activation, since PMA-induced superoxide generation was unaffected. We conclude that activation of PMN adherent to extracellular matrix proteins increases endothelial permeability to albumin and that this response is dependent on PMN adhesion to the matrix. The results support the concept that PMN-mediated increase in endothelial permeability is the result of “targeted” release of PMN products independent of whether the PMN are adherent to the extracellular matrix or the endothelium.

1998 ◽  
Vol 275 (1) ◽  
pp. L126-L138 ◽  
Author(s):  
Theresa M. Curtis ◽  
Robert F. Rotundo ◽  
Peter A. Vincent ◽  
Paula J. McKeown-Longo ◽  
Thomas M. Saba

Exposure of confluent pulmonary arterial endothelial monolayers to tumor necrosis factor (TNF)-α causes both a reorganization and/or disruption of fibronectin (Fn) in the extracellular matrix and an increase in transendothelial protein permeability. However, the factors initiating this response to TNF-α have not been defined. Because TNF-α can induce proteinase expression in endothelial cells, we determined whether proteinases cause both the alteration of the Fn matrix and the permeability increase as is often speculated. Incubation of calf pulmonary arterial endothelial monolayers with TNF-α (200 U/ml) for 18 h caused a disruption of the Fn matrix and an increase in transendothelial protein permeability. A reduced colocalization of cell-surface α5β1-Fn integrins with the Fn fibers in focal contacts was also observed. TNF-α treatment of endothelial monolayers with matrices prelabeled with125I-human Fn (hFn) did not cause the release of Fn fragments or alter the content of Fn antigen in the medium as analyzed by SDS-PAGE coupled with autoradiography. Both the content and fragmentation pattern of Fn within the cell layer and the insoluble Fn matrix also appeared unchanged after TNF-α exposure as confirmed by Western immunoblot. Fn-substrate zymography revealed that TNF-α increased the expression of two proteinases within the conditioned medium in which activity could be blocked by aprotinin but not by EDTA, 1,10-phenanthroline, leupeptin, or pepstatin. However, inhibition of the Fn proteolytic activity of these two serine proteinases did not prevent either the TNF-α-induced disruption of the Fn matrix or the increase in permeability. Thus the reorganization and/or disruption of the Fn matrix and the temporally associated increase in endothelial permeability caused by TNF-α appear not to be due to proteolytic degradation of Fn within the extracellular matrix. In contrast, decreased α5β1-Fn integrin interaction with Fn fibers in the matrix may be important in the response to TNF-α exposure.


1991 ◽  
Vol 66 (06) ◽  
pp. 715-724 ◽  
Author(s):  
Albert Dekker ◽  
André A Poot ◽  
Jan A van Mourik ◽  
Martin P A Workel ◽  
Tom Beugeling ◽  
...  

SummaryEndothelial cell seeding may improve the patency of synthetic vascular grafts provided that platelet reactivity of non-endothelialized sites is not increased. We have investigated if surface-adsorbed monoclonal antibodies directed against endothelial cell membrane proteins and against extracellular matrix proteins promote the adhesion and proliferation of cultured human endothelial cells, without causing platelet deposition at non-endothelialized sites. Adhesion of endothelial cells onto polyethylene coated with monoclonal antibodies directed against endothelial cell-specific membrane antigens, integrin receptors and glycoprotein CD31 was equal to or higher than adhesion onto fibronectin-coated polyethylene. Endothelial cells did not proliferate on these surface-adsorbed antibodies. However, pre-coating of polyethylene with mixtures of endothelial cell-specific monoclonal antibodies and monoclonal antibodies directed against fibronectin or von Willebrand factor, resulted in relatively high adhesion and optimal proliferation. Platelet reactivity of the polyethylene surface was found to significantly increase after adsorption of fibronectin, endothelial cell-specific monoclonal antibody or its Fc fragments. In contrast, adsorption of F(ab')2 fragments of endothelial cell-specific monoclonal antibody did not promote platelet deposition. Therefore, it is concluded that coating of vascular graft materials with mixtures of F(ab')2 fragments of monoclonal antibodies specifically directed against endothelial cells and against extracellular matrix proteins may be an effective way to both promote the growth of seeded endothelial cells and limit platelet-graft interaction.


Blood ◽  
1987 ◽  
Vol 69 (5) ◽  
pp. 1531-1534 ◽  
Author(s):  
LA Sporn ◽  
VJ Marder ◽  
DD Wagner

Abstract Large multimers of von Willebrand factor (vWf) are released from the Weibel-Palade bodies of cultured endothelial cells following treatment with a secretagogue (Sporn et al, Cell 46:185, 1986). These multimers were shown by immunofluorescent staining to bind more extensively to the extracellular matrix of human foreskin fibroblasts than constitutively secreted vWf, which is composed predominantly of dimeric molecules. Increased binding of A23187-released vWf was not due to another component present in the releasate, since releasate from which vWf was adsorbed, when added together with constitutively secreted vWf, did not promote binding. When iodinated plasma vWf was overlaid onto the fibroblasts, the large forms bound preferentially to the matrix. These results indicated that the enhanced binding of the vWf released from the Weibel-Palade bodies was likely due to its large multimeric size. It appears that multivalency is an important component of vWf interaction with the extracellular matrix, just as has been shown for vWf interaction with platelets. The pool of vWf contained within the Weibel-Palade bodies, therefore, is not only especially suited for platelet binding, but also for interaction with the extracellular matrix.


2020 ◽  
Vol 77 (12) ◽  
pp. 3831-3841
Author(s):  
Lidia Muscariello ◽  
Barbara De Siena ◽  
Rosangela Marasco

AbstractThe gut microbiota is a complex microbial ecosystem where bacteria, through mutual interactions, cooperate in maintaining of wellbeing and health. Lactobacilli are among the most important constituents of human and animal intestinal microbiota and include many probiotic strains. Their presence ensures protection from invasion of pathogens, as well as stimulation of the immune system and protection of the intestinal flora, often exerted through the ability to interact with mucus and extracellular matrix components. The main factors responsible for mediating adhesion of pathogens and commensals to the gut are cell surface proteins that recognize host targets, as mucus layer and extracellular matrix proteins. In the last years, several adhesins have been reported to be involved in lactobacilli–host interaction often miming the same mechanism used by pathogens.


1989 ◽  
Vol 66 (3) ◽  
pp. 1471-1476 ◽  
Author(s):  
H. Lum ◽  
P. J. Del Vecchio ◽  
A. S. Schneider ◽  
M. S. Goligorsky ◽  
A. B. Malik

We examined whether the increase in endothelial albumin permeability induced by alpha-thrombin is dependent on extracellular Ca2+ influx. Permeability of 125I-albumin across confluent monolayers of cultured bovine pulmonary artery endothelial cells was measured before and after the addition of 0.1 microM alpha-thrombin. In the presence of normal extracellular Ca2+ concentration ([Ca2+]o, 1000 microM), alpha-thrombin produced a 175 +/- 10% increase in 125I-albumin permeability. At lower [Ca2+]o (100, 10, 1, or less than 1 microM), alpha-thrombin caused a 140% increase in permeability (P less than 0.005). LaCl3 (1 mM), which competes for Ca2+ entry, blunted 38% of the increase in permeability. Preloading endothelial monolayers with quin2 to buffer cytosolic Ca2+ (Cai2+) produced a dose-dependent inhibition of the increase in 125I-albumin permeability. Preincubation with nifedipine or verapamil was ineffective in reducing the thrombin-induced permeability increase. A 60 mM K+ isosmotic solution did not alter base-line endothelial permeability. alpha-Thrombin increased [Ca2+]i in a dose-dependent manner and the 45Ca2+ influx rate. Extracellular medium containing 60 mM K+ did not increase 45Ca2+ influx, and nifedipine did not block the rise in 45Ca2+ influx caused by alpha-thrombin. Ca2+ flux into endothelial cells induced by alpha-thrombin does not occur through voltage-sensitive channels but may involve receptor-operated channels. In conclusion, the increase in endothelial albumin permeability caused by alpha-thrombin is dependent on Ca2+ influx and intracellular Ca2+ mobilization.


2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Yi Chen ◽  
Dan Tang ◽  
Linjie Zhu ◽  
Tianjie Yuan ◽  
Yingfu Jiao ◽  
...  

Heterogeneous nuclear ribonucleoprotein A2/B1 (hnRNPA2/B1) is a protein involved in the regulation of RNA processing, cell metabolism, migration, proliferation, and apoptosis. However, the effect of hnRNPA2/B1 on injured endothelial cells (ECs) remains unclear. We investigated the effect of hnRNPA2/B1 on lipopolysaccharide- (LPS-) induced vascular endothelial injury in human umbilical vein endothelial cells (HUVECs) and the underlying mechanisms. LPS was used to induce EC injury, and the roles of hnRNPA2/B1 in EC barrier dysfunction and inflammatory responses were measured by testing endothelial permeability and the expression of inflammatory factors after the suppression and overexpression of hnRNPA2/B1. To explore the underlying mechanism by which hnRNPA2/B1 regulates endothelial injury, we studied the VE-cadherin/β-catenin pathway and NF-κB activation in HUVECs. The results showed that hnRNPA2/B1 was elevated in LPS-stimulated HUVECs. Moreover, knockdown of hnRNPA2/B1 aggravated endothelial injury by increasing EC permeability and promoting the secretion of the inflammatory cytokines TNF-α, IL-1β, and IL-6. Overexpression of hnRNPA2/B1 can reduce the permeability and inflammatory response of HUVEC stimulated by LPS in vitro, while increasing the expression of VE-Cadherin and β-catenin. Furthermore, the suppression of hnRNPA2/B1 increased the LPS-induced NF-κB activation and reduced the VE-cadherin/β-catenin pathway. Taken together, these results suggest that hnRNPA2/B1 can regulate LPS-induced EC damage through regulating the NF-κB and VE-cadherin/β-catenin pathways.


1992 ◽  
Vol 262 (1) ◽  
pp. L21-L31 ◽  
Author(s):  
P. G. Phillips ◽  
L. Birnby ◽  
L. A. Di Bernardo ◽  
T. J. Ryan ◽  
M. F. Tsan

Confluent calf pulmonary artery endothelial monolayers exposed to 95% oxygen for 1, 2, or 3 days exhibit a time-dependent increase in adherence to substratum, which closely parallels changes in actin cytoarchitecture and the distribution of focal contact proteins vinculin and talin. Oxygen exposure also resulted in elevated plasminogen activator (PA) activity in conditioned media (CM) and in cytoskeletal protein- and focal contact protein-enriched fractions, with highest levels achieved in the latter two fractions at 48 h after oxygen exposure. PAs have been shown to participate in dismantling of extracellular matrix in a number of physiological and pathological situations. Immunocytochemical studies demonstrated extensive restructuring of matrix proteins collagen IV, laminin, and fibronectin, which correlated temporally with elevated PA levels. Further, when protease-containing cell fractions were used to study degradation of isolated matrices, those obtained from hyperoxia-exposed cells were substantially more active than those from normoxia-exposed cells. Our data suggest that hyperoxia-induced production of PA (and perhaps other proteases) may be partly responsible for degradation of the extracellular matrix of endothelial cells.


2018 ◽  
Vol 27 (148) ◽  
pp. 180018 ◽  
Author(s):  
Magnus Paulsson ◽  
Kristian Riesbeck

Haemophilus influenzae,Moraxella catarrhalisandPseudomonas aeruginosaare common Gram-negative pathogens associated with an array of pulmonary diseases. All three species have multiple adhesins in their outer membrane,i.e.surface structures that confer the ability to bind to surrounding cells, proteins or tissues. This mini-review focuses on proteins with high affinity for the components of the extracellular matrix such as collagen, laminin, fibronectin and vitronectin. Adhesins are not structurally related and may be lipoproteins, transmembrane porins or large protruding trimeric auto-transporters. They enable bacteria to avoid being cleared together with mucus by attaching to patches of exposed extracellular matrix, or indirectly adhering to epithelial cells using matrix proteins as bridging molecules. As more adhesins are being unravelled, it is apparent that bacterial adhesion is a highly conserved mechanism, and that most adhesins target the same regions on the proteins of the extracellular matrix. The surface exposed adhesins are prime targets for new vaccines and the interactions between proteins are often possible to inhibit with interfering molecules,e.g. heparin. In conclusion, this highly interesting research field of microbiology has unravelled host–pathogen interactions with high therapeutic potential.


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