scholarly journals Endothelial Focal Adhesions Are Functional Obstacles for Leukocytes During Basolateral Crawling

2021 ◽  
Vol 12 ◽  
Author(s):  
Janine J. G. Arts ◽  
Eike K. Mahlandt ◽  
Lilian Schimmel ◽  
Max L. B. Grönloh ◽  
Sanne van der Niet ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Inflammatory Response ◽  
Focal Adhesions ◽  
Small Gtpase ◽  
Endothelial Monolayer ◽  
Tirf Microscopy ◽  
Migration Path ◽  
Subendothelial Space

An inflammatory response requires leukocytes to migrate from the circulation across the vascular lining into the tissue to clear the invading pathogen. Whereas a lot of attention is focused on how leukocytes make their way through the endothelial monolayer, it is less clear how leukocytes migrate underneath the endothelium before they enter the tissue. Upon finalization of the diapedesis step, leukocytes reside in the subendothelial space and encounter endothelial focal adhesions. Using TIRF microscopy, we show that neutrophils navigate around these focal adhesions. Neutrophils recognize focal adhesions as physical obstacles and deform to get around them. Increasing the number of focal adhesions by silencing the small GTPase RhoJ slows down basolateral crawling of neutrophils. However, apical crawling and diapedesis itself are not affected by RhoJ depletion. Increasing the number of focal adhesions drastically by expressing the Rac1 GEF Tiam1 make neutrophils to avoid migrating underneath these Tiam1-expressing endothelial cells. Together, our results show that focal adhesions mark the basolateral migration path of neutrophils.

Thrombopoietin Stimulates the Formation of Endothelial Cell-Cell Contacts and Activates the Small GTPase Rap1.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 3713-3713
Author(s):  
Marloes R. Tijssen ◽  
Franca di Summa ◽  
Anne-Marieke van Stalborch ◽  
C. Ellen Van der Schoot ◽  
Jaap D. van Buul ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Electrical Resistance ◽  
Umbilical Vein ◽  
Small Gtpase ◽  
Endothelial Monolayer ◽  
Impedance Sensing ◽  
Cell Contacts ◽  
Umbilical Vein Endothelial Cells ◽  
Cell Cell

Abstract In addition to hematopoietic cells, the receptor for thrombopoietin (Tpo), c-Mpl, is expressed on human umbilical vein endothelial cells (HUVEC). In this study, we demonstrated that Mpl mRNA and protein can also be detected in immortalized human bone marrow endothelial cells (HBMEC). Furthermore, it was investigated whether Tpo affects endothelial monolayer integrity by either cell spreading or cell-cell contacts. By continuously monitoring the electrical resistance of freshly plated HUVEC or HBMEC with ECIS (electric cell-substrate impedance sensing), we observed a significant increase in the electrical resistance when endothelial cells were treated with 100 ng/ml of Tpo just prior to seeding, as shown in the figure below. This increase in electrical resistance was not due to increased cell adhesion or proliferation of the endothelial cells. However, a significant increase in initial spreading could be detected. Besides its effect on spreading, Tpo increased the electrical resistance of a confluent endothelial monolayer when compared to untreated monolayers. This indicates that Tpo promotes the formation of endothelial cell-cell contacts. Indeed, a decrease in immunostaining levels of phosphotyrosine could be observed in monolayers treated with Tpo. Also the junctional protein VE-cadherin showed diminished co-localization with phosphotyrosine staining when cells were treated with Tpo. The small GTPase Rap1 plays an important role in the formation of endothelial cell-cell contacts. In a pull-down experiment, using RalGDS as bait for active Rap1, we could demonstrate that Tpo transiently activates Rap1 in HUVEC. Thus, these results may put Tpo forward as a regulator of endothelial cell-cell contacts, possibly after vascular damage and subsequent release of Tpo by activated platelets. To our knowledge, Tpo is the first cytokine exerting this effect on endothelial cells. Figure Figure

Small GTP-binding Protein RalA Associates with Weibel-Palade Bodies in Endothelial Cells

1999 ◽  
Vol 82 (09) ◽  
pp. 1177-1181 ◽  
Author(s):  
Hubert de Leeuw ◽  
Pauline Wijers-Koster ◽  
Jan van Mourik ◽  
Jan Voorberg
Keyword(s):  
Endothelial Cells ◽  
Binding Proteins ◽  
Binding Protein ◽  
Control Release ◽  
Small Gtpase ◽  
Gtp Binding Protein ◽  
Two Dimensional Gel Electrophoresis ◽  
Gtp Binding Proteins ◽  
Dense Granules ◽  
Gtp Binding

SummaryIn endothelial cells von Willebrand factor (vWF) and P-selectin are stored in dense granules, so-called Weibel-Palade bodies. Upon stimulation of endothelial cells with a variety of agents including thrombin, these organelles fuse with the plasma membrane and release their content. Small GTP-binding proteins have been shown to control release from intracellular storage pools in a number of cells. In this study we have investigated whether small GTP-binding proteins are associated with Weibel-Palade bodies. We isolated Weibel-Palade bodies by centrifugation on two consecutive density gradients of Percoll. The dense fraction in which these subcellular organelles were highly enriched, was analysed by SDS-PAGE followed by GTP overlay. A distinct band with an apparent molecular weight of 28,000 was observed. Two-dimensional gel electrophoresis followed by GTP overlay revealed the presence of a single small GTP-binding protein with an isoelectric point of 7.1. A monoclonal antibody directed against RalA showed reactivity with the small GTP-binding protein present in subcellular fractions that contain Weibel-Palade bodies. The small GTPase RalA was previously identified on dense granules of platelets and on synaptic vesicles in nerve terminals. Our observations suggest that RalA serves a role in regulated exocytosis of Weibel-Palade bodies in endothelial cells.

ZUR SUBMIKROSKOPISCHEN STRUKTUR DER RATTENSCHILDDRÜSE ELEKTRONENMIKROSKOPISCHE UNTERSUCHUNGEN AN DER BASIS DES SCHILDDRÜSENFOLLIKELS

1960 ◽  
Vol XXXV (III) ◽  
pp. 334-350 ◽  
Author(s):  
U. Waller
Keyword(s):  
Endothelial Cells ◽  
Basement Membranes ◽  
The Other ◽  
Small Vesicle ◽  
Thyroid Follicle ◽  
Basal Secretion ◽  
Structural Principle ◽  
Thyroid Epithelial Cell ◽  
Endocrine Organs ◽  
Subendothelial Space

ABSTRACT This is a description of ultramicroscopic structures at the base of the thyroid follicle. The structural principle of the subendothelial or interfollicular space, namely basement membranes closely following both the endothelial cells of the capillaries and the epithelial cells of the thyroid, corresponds to that described by other authors in the other endocrine organs. Especially shown are small vesicle like decreases of intensity in the subendothelial space, causing bulges in both the subepithelial basement membrane and the membrane covering the endothelial cell pores thereby forming pseudopores. This membrane is in several parts a double one. The possible role played by the above mentioned structures in the basal secretion of the thyroid epithelial cell is discussed.

scholarly journals Ethanol inhibits monocyte chemotactic protein-1 expression in interleukin-1β-activated human endothelial cells

2005 ◽  
Vol 289 (4) ◽  
pp. H1669-H1675 ◽  
Author(s):  
John P. Cullen ◽  
Shariq Sayeed ◽  
Ying Jin ◽  
Nicholas G. Theodorakis ◽  
James V. Sitzmann ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Umbilical Vein ◽  
Binding Activity ◽  
Protective Effects ◽  
Monocyte Adhesion ◽  
Monocyte Chemotactic Protein ◽  
Chemotactic Protein ◽  
Subendothelial Space ◽  
Umbilical Vein Endothelial Cells

The aim of this study was to determine the effect of ethanol (EtOH) on endothelial monocyte chemotactic protein-1 (MCP-1) expression. IL-1β increased the production of MCP-1 by human umbilical vein endothelial cells from undetectable levels to ∼900 pg/ml at 24 h. EtOH dose-dependently inhibited IL-1β-stimulated MCP-1 secretion as determined by ELISA: 25 ± 1%, 35 ± 7%, and 65 ± 5% inhibition for 1, 10, and 100 mM EtOH, respectively, concomitant with inhibition of monocyte adhesion to activated endothelial cells. Similarly, EtOH dose-dependently inhibited IL-1β-stimulated MCP-1 mRNA expression. Experiments with actinomycin D demonstrated that EtOH decreased the stability of MCP-1 mRNA. In addition, EtOH significantly reduced NF-κB and AP-1 binding activity induced by IL-1β and inhibited MCP-1 gene transcription. Binding of 125I-labeled MCP-1 to its receptor (CCR2) on THP-1 human monocytic cells was not affected by EtOH treatment. Modulation of the expression of MCP-1 represents a mechanism whereby EtOH could inhibit atherogenesis by blocking the crucial early step of monocyte adhesion and subsequent recruitment to the subendothelial space. These actions of EtOH may underlie, in part, its cardiovascular protective effects in vivo.

scholarly journals ROCK and mDia1 antagonize in Rho-dependent Rac activation in Swiss 3T3 fibroblasts

2002 ◽  
Vol 157 (5) ◽  
pp. 819-830 ◽  
Author(s):  
Takahiro Tsuji ◽  
Toshimasa Ishizaki ◽  
Muneo Okamoto ◽  
Chiharu Higashida ◽  
Kazuhiro Kimura ◽  
...  
Keyword(s):  
Focal Adhesions ◽  
Small Gtpase ◽  
Dominant Negative ◽  
Stress Fibers ◽  
Induced Membrane ◽  
3T3 Fibroblasts ◽  
C3 Exoenzyme ◽  
Swiss 3T3 ◽  
Swiss 3T3 Fibroblasts ◽  
Membrane Ruffle

The small GTPase Rho acts on two effectors, ROCK and mDia1, and induces stress fibers and focal adhesions. However, how ROCK and mDia1 individually regulate signals and dynamics of these structures remains unknown. We stimulated serum-starved Swiss 3T3 fibroblasts with LPA and compared the effects of C3 exoenzyme, a Rho inhibitor, with those of Y-27632, a ROCK inhibitor. Y-27632 treatment suppressed LPA-induced formation of stress fibers and focal adhesions as did C3 exoenzyme but induced membrane ruffles and focal complexes, which were absent in the C3 exoenzyme-treated cells. This phenotype was suppressed by expression of N17Rac. Consistently, the amount of GTP-Rac increased significantly by Y-27632 in LPA-stimulated cells. Biochemically, Y-27632 suppressed tyrosine phosphorylation of paxillin and focal adhesion kinase and not that of Cas. Inhibition of Cas phosphorylation with PP1 or expression of a dominant negative Cas mutant inhibited Y-27632–induced membrane ruffle formation. Moreover, Crk-II mutants lacking in binding to either phosphorylated Cas or DOCK180 suppressed the Y-27632–induced membrane ruffle formation. Finally, expression of a dominant negative mDia1 mutant also inhibited the membrane ruffle formation by Y-27632. Thus, these results have revealed the Rho-dependent Rac activation signaling that is mediated by mDia1 through Cas phosphorylation and antagonized by the action of ROCK.

scholarly journals Regulation of the inflammatory response of vascular endothelial cells by EPAC1

2012 ◽  
Vol 166 (2) ◽  
pp. 434-446 ◽  
Author(s):  
Euan Parnell ◽  
Brian O Smith ◽  
Timothy M Palmer ◽  
Anna Terrin ◽  
Manuela Zaccolo ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Inflammatory Response ◽  
Vascular Endothelial Cells ◽  
Vascular Endothelial

scholarly journals Transport of Apolipoprotein B-Containing Lipoproteins through Endothelial Cells Is Associated with Apolipoprotein E-Carrying HDL-Like Particle Formation

2018 ◽  
Vol 19 (11) ◽  
pp. 3593 ◽  
Author(s):  
Hong Yang ◽  
Ningya Zhang ◽  
Emmanuel Okoro ◽  
Zhongmao Guo
Keyword(s):  
Endothelial Cells ◽  
Apolipoprotein B ◽  
Density Lipoprotein ◽  
High Density ◽  
Low Density ◽  
Endothelial Monolayer ◽  
Aortic Endothelial Cells ◽  
Pass Through ◽  
Intermediate Density ◽  
Current Report

Passage of apolipoprotein B-containing lipoproteins (apoB-LPs), i.e., triglyceride-rich lipoproteins (TRLs), intermediate-density lipoproteins (IDLs), and low-density lipoproteins (LDLs), through the endothelial monolayer occurs in normal and atherosclerotic arteries. Among these lipoproteins, TRLs and IDLs are apoE-rich apoB-LPs (E/B-LPs). Recycling of TRL-associated apoE has been shown to form apoE-carrying high-density lipoprotein (HDL)-like (HDLE) particles in many types of cells. The current report studied the formation of HDLE particles by transcytosis of apoB-LPs through mouse aortic endothelial cells (MAECs). Our data indicated that passage of radiolabeled apoB-LPs, rich or poor in apoE, through the MAEC monolayer is inhibited by filipin and unlabeled competitor lipoproteins, suggesting that MAECs transport apoB-LPs via a caveolae-mediated pathway. The cholesterol and apoE in the cell-untreated E/B-LPs, TRLs, IDLs, and LDLs distributed primarily in the low-density (LD) fractions (d ≤ 1.063). A substantial portion of the cholesterol and apoE that passed through the MAEC monolayer was allotted into the high-density (HD) (d > 1.063) fractions. In contrast, apoB was detectable only in the LD fractions before or after apoB-LPs were incubated with the MAEC monolayer, suggesting that apoB-LPs pass through the MAEC monolayer in the forms of apoB-containing LD particles and apoE-containing HD particles.

Sign in / Sign up

Export Citation Format

Share Document