scholarly journals Septin Roles and Mechanisms in Organization of Endothelial Cell Junctions

2020 ◽  
Author(s):  
Joanna Kim ◽  
John A. Cooper
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Adherens Junctions ◽  
Cell Junctions ◽  
Cell Junction ◽  
Cell Contact ◽  
Junction Molecules ◽  
Tnf Α ◽  
Multiple Cell ◽  
Cell Cell

AbstractSeptins play an important role in regulating the barrier function of the endothelial monolayer of the microvasculature. Depletion of septin 2 protein alters the organization of vascular endothelial (VE)-cadherin at cell-cell adherens junctions as well as the dynamics of membrane protrusions at endothelial cell-cell contact sites. Here, we report the discovery that localization of septin 2 at endothelial cell junctions is important for the distribution of a number of other junctional molecules. We also found that treatment of microvascular endothelial cells with the inflammatory mediator TNF-α led to sequestration of septin 2 away from cell junctions and into the cytoplasm, without an effect on the overall level of septin 2 protein. Interestingly, TNF-α treatment of endothelial monolayers produced effects similar to those of depletion of septin 2 on various molecular components of adherens junctions (AJs) and tight junctions (TJs). Immunofluorescence staining revealed disruption of the integrity of AJs and TJs at cell-cell junctions without significant changes in protein expression except for VE-cadherin and nectin-2. To investigate the mechanism of junctional localization of septin 2, we mutated the polybasic motif of septin 2, which is proposed to interact with PIP2 in the plasma membrane. Overexpression of PIP2-binding mutant (PIP2BM) septin 2 led to loss of septin 2 from cell junctions with accumulation in the cytoplasm. This redistribution of septin 2 away from the membrane led to effects on cell junction molecules similar to those observed for depletion of septin 2. We conclude that septin localization to the membrane is essential for function and that septins support the localization of multiple cell junction molecules in endothelial cells.

scholarly journals PKM2 regulates endothelial cell junction dynamics and angiogenesis via ATP production

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Jesús Gómez-Escudero ◽  
Cristina Clemente ◽  
Diego García-Weber ◽  
Rebeca Acín-Pérez ◽  
Jaime Millán ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Inflammatory Disease ◽  
Chronic Inflammatory Disease ◽  
Cell Junctions ◽  
Cell Junction ◽  
Collective Migration ◽  
Sprouting Angiogenesis ◽  
Cell Cell

Abstract Angiogenesis, the formation of new blood vessels from pre-existing ones, occurs in pathophysiological contexts such as wound healing, cancer, and chronic inflammatory disease. During sprouting angiogenesis, endothelial tip and stalk cells coordinately remodel their cell-cell junctions to allow collective migration and extension of the sprout while maintaining barrier integrity. All these processes require energy, and the predominant ATP generation route in endothelial cells is glycolysis. However, it remains unclear how ATP reaches the plasma membrane and intercellular junctions. In this study, we demonstrate that the glycolytic enzyme pyruvate kinase 2 (PKM2) is required for sprouting angiogenesis in vitro and in vivo through the regulation of endothelial cell-junction dynamics and collective migration. We show that PKM2-silencing decreases ATP required for proper VE-cadherin internalization/traffic at endothelial cell-cell junctions. Our study provides fresh insight into the role of ATP subcellular compartmentalization in endothelial cells during angiogenesis. Since manipulation of EC glycolysis constitutes a potential therapeutic intervention route, particularly in tumors and chronic inflammatory disease, these findings may help to refine the targeting of endothelial glycolytic activity in disease.

scholarly journals Regulation of Endothelial Cell Motility by Complexes of Tetraspan Molecules CD81/TAPA-1 and CD151/PETA-3 with α3β1 Integrin Localized at Endothelial Lateral Junctions

1998 ◽  
Vol 141 (3) ◽  
pp. 791-804 ◽  
Author(s):  
María Yáñez-Mó ◽  
Arántzazu Alfranca ◽  
Carlos Cabañas ◽  
Mónica Marazuela ◽  
Reyes Tejedor ◽  
...  
Keyword(s):  
Wound Healing ◽  
Endothelial Cell ◽  
Cell Motility ◽  
Cell Polarization ◽  
Cell Junctions ◽  
Cell Junction ◽  
Cell Contact ◽  
Collagen Gels ◽  
Α3β1 Integrin ◽  
Cell Cell

Cell-to-cell junction structures play a key role in cell growth rate control and cell polarization. In endothelial cells (EC), these structures are also involved in regulation of vascular permeability and leukocyte extravasation. To identify novel components in EC intercellular junctions, mAbs against these cells were produced and selected using a morphological screening by immunofluorescence microscopy. Two novel mAbs, LIA1/1 and VJ1/16, specifically recognized a 25-kD protein that was selectively localized at cell–cell junctions of EC, both in the primary formation of cell monolayers and when EC reorganized in the process of wound healing. This antigen corresponded to the recently cloned platelet-endothelial tetraspan antigen CD151/PETA-3 (platelet-endothelial tetraspan antigen-3), and was consistently detected at EC cell–cell contact sites. In addition to CD151/PETA-3, two other members of the tetraspan superfamily, CD9 and CD81/ TAPA-1 (target of antiproliferative antibody-1), localized at endothelial cell-to-cell junctions. Biochemical analysis demonstrated molecular associations among tetraspan molecules themselves and those of CD151/ PETA-3 and CD9 with α3β1 integrin. Interestingly, mAbs directed to both CD151/PETA-3 and CD81/ TAPA-1 as well as mAb specific for α3 integrin, were able to inhibit the migration of ECs in the process of wound healing. The engagement of CD151/PETA-3 and CD81/TAPA-1 inhibited the movement of individual ECs, as determined by quantitative time-lapse video microscopy studies. Furthermore, mAbs against the CD151/PETA-3 molecule diminished the rate of EC invasion into collagen gels. In addition, these mAbs were able to increase the adhesion of EC to extracellular matrix proteins. Together these results indicate that CD81/TAPA-1 and CD151/PETA-3 tetraspan molecules are components of the endothelial lateral junctions implicated in the regulation of cell motility, either directly or by modulation of the function of the associated integrin heterodimers.

scholarly journals Excess centrosomes disrupt vascular lumenization and endothelial cell adherens junctions

Angiogenesis ◽  
2020 ◽  
Vol 23 (4) ◽  
pp. 567-575
Author(s):  
Danielle B. Buglak ◽  
Erich J. Kushner ◽  
Allison P. Marvin ◽  
Katy L. Davis ◽  
Victoria L. Bautch
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Cell Polarity ◽  
Adherens Junctions ◽  
Cell Junctions ◽  
Microtubule Organizing Center ◽  
Sprouting Angiogenesis ◽  
Organizing Center ◽  
Important Regulator ◽  
Cell Cell

Abstract Proper blood vessel formation requires coordinated changes in endothelial cell polarity and rearrangement of cell–cell junctions to form a functional lumen. One important regulator of cell polarity is the centrosome, which acts as a microtubule organizing center. Excess centrosomes perturb aspects of endothelial cell polarity linked to migration, but whether centrosome number influences apical–basal polarity and cell–cell junctions is unknown. Here, we show that excess centrosomes alter the apical–basal polarity of endothelial cells in angiogenic sprouts and disrupt endothelial cell–cell adherens junctions. Endothelial cells with excess centrosomes had narrower lumens in a 3D sprouting angiogenesis model, and zebrafish intersegmental vessels had reduced perfusion following centrosome overduplication. These results indicate that endothelial cell centrosome number regulates proper lumenization downstream of effects on apical–basal polarity and cell–cell junctions. Endothelial cells with excess centrosomes are prevalent in tumor vessels, suggesting how centrosomes may contribute to tumor vessel dysfunction.

scholarly journals Excess Centrosomes Disrupt Vascular Lumenization and Endothelial Cell Adherens Junctions

2019 ◽  
Author(s):  
Danielle B Buglak ◽  
Erich J Kushner ◽  
Allison P Marvin ◽  
Katy L Davis ◽  
Victoria L Bautch
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Cell Polarity ◽  
Adherens Junctions ◽  
Cell Junctions ◽  
Microtubule Organizing Center ◽  
Sprouting Angiogenesis ◽  
Organizing Center ◽  
Important Regulator ◽  
Cell Cell

ABSTRACTProper blood vessel formation requires coordinated changes in endothelial cell polarity and rearrangement of cell-cell junctions to form a functional lumen. One important regulator of cell polarity is the centrosome, which acts as a microtubule organizing center. Excess centrosomes perturb aspects of endothelial cell polarity linked to migration, but whether centrosome number influences apical-basal polarity and cell-cell junctions is unknown. Here, we show that excess centrosomes alter the apical-basal polarity of endothelial cells in angiogenic sprouts and disrupt endothelial cell-cell adherens junctions. Endothelial cells with excess centrosomes had narrower lumens in a 3D sprouting angiogenesis model, and zebrafish intersegmental vessels had reduced perfusion following centrosome overduplication. These results indicate that endothelial cell centrosome number regulates proper lumenization downstream of effects on apical-basal polarity and cell-cell junctions. Endothelial cells with excess centrosomes are prevalent in tumor vessels, suggesting how centrosomes may contribute to tumor vessel dysfunction.

scholarly journals Nuclear SUN1 stabilizes endothelial cell junctions to regulate blood vessel formation

2021 ◽  
Author(s):  
Danielle B Buglak ◽  
Ariel L Gold ◽  
Allison P Marvin ◽  
Shea N Ricketts ◽  
Morgan Oatley ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Blood Vessel ◽  
Barrier Function ◽  
Cell Junctions ◽  
Cell Junction ◽  
Peripheral Cell ◽  
Blood Vessel Formation ◽  
Vessel Formation ◽  
Cell Cell

Endothelial cells line all blood vessels and coordinate blood vessel formation and the blood-tissue barrier via endothelial cell-cell junctions. The nucleus also regulates endothelial cell behaviors, but the mechanisms are poorly understood. Here we show that nuclear-localized SUN1, a LINC complex component that connects the nucleus to the cytoskeleton, regulates endothelial cell-cell junction communication and blood vessel formation. Loss of murine endothelial Sun1 impaired blood vessel formation and destabilized junctions. At the cellular level, SUN1 stabilized endothelial cell-cell junctions and promoted barrier function. Abnormal SUN1-depleted junctions resembled those seen with loss of microtubules, and they were accompanied by impaired microtubule dynamics and actomyosin hypercontractility. Angiogenic sprouts formed but retracted in SUN1-depleted endothelial cells, and vessels of zebrafish lacking SUN1 had abnormal extension and were defective in forming connections. Thus, endothelial SUN1 regulates peripheral cell-cell junctions from the nucleus, likely via microtubule-based interactions, and this long-range regulation is important for blood vessel formation and barrier function.

scholarly journals Spatial and temporal relationships between cadherins and PECAM-1 in cell-cell junctions of human endothelial cells.

1994 ◽  
Vol 126 (1) ◽  
pp. 247-258 ◽  
Author(s):  
O Ayalon ◽  
H Sabanai ◽  
M G Lampugnani ◽  
E Dejana ◽  
B Geiger
Keyword(s):  
Endothelial Cells ◽  
Plasma Membrane ◽  
Vascular System ◽  
Adherens Junctions ◽  
Microscopic Analysis ◽  
Membrane Receptors ◽  
Temporal Organization ◽  
Cell Junctions ◽  
Short Treatment ◽  
Cell Cell

The integrity of the endothelial layer, which lines the entire cavity of the vascular system, depends on tight adhesion of the cells to the underlying basement membrane as well as to each other. It has been previously shown that such interactions occur via membrane receptors that determine the specificity, topology, and mechanical properties of the surface adhesion. Cell-cell junctions between endothelial cells, in culture and in situ, involve both Ca(2+)-dependent and -independent mechanisms that are mediated by distinct adhesion molecules. Ca(2+)-dependent cell-cell adhesion occurs mostly via members of the cadherin family, which locally anchor the microfilament system to the plasma membrane, in adherens junctions. Ca(2+)-independent adhesions were reported to mainly involve members of the Ig superfamily. In this study, we performed three-dimensional microscopic analysis of the relative subcellular distributions of these two endothelial intercellular adhesion systems. We show that cadherins are located at adjacent (usually more apical), yet clearly distinct domains of the lateral plasma membrane, compared to PECAM-1. Moreover, cadherins were first organized in adherens junctions within 2 h after seeding of endothelial cells, forming multiple lateral patches which developed into an extensive belt-like structure over a period of 24 h. PECAM-1 became associated with surface adhesions significantly later and became progressively associated with the cadherin-containing adhesions. Cadherins and PECAM-1 also differed in their detergent extractability, reflecting differences in their mode of association with the cytoskeleton. Moreover, the two adhesion systems could be differentially modulated since short treatment with the Ca2+ chelator EGTA, disrupted the cadherin junctions leaving PECAM-1 apparently intact. These results confirm that endothelial cells possess distinct intercellular contact mechanisms that differ in their spatial and temporal organization as well as in their functional properties.

scholarly journals Monocytes Upregulate Endothelial Cell Expression of Tissue Factor: A Role for Cell-Cell Contact and Cross-Talk

Blood ◽  
1997 ◽  
Vol 89 (2) ◽  
pp. 541-549 ◽  
Author(s):  
Emanuela Napoleone ◽  
Angelomaria Di Santo ◽  
Roberto Lorenzet
Keyword(s):  
Endothelial Cell ◽  
Tissue Factor ◽  
Cross Talk ◽  
Umbilical Vein ◽  
Cell Types ◽  
Cell Contact ◽  
Tnf Α ◽  
Factor Α ◽  
Cell Expression ◽  
Cell Cell

Abstract Monocytes and endothelial cells interact at sites of vascular injury during inflammatory response, thrombosis, and development of atherosclerotic lesions. Such interactions result in modulation of several biological functions of the two cell types. Because both cells, on appropriate stimulation, synthesize tissue factor (TF), we examined the effect of human umbilical vein endothelial cell (HUVEC)/monocyte coculture on the expression of TF. We found that the coincubation resulted in TF generation, which was maximal at 4 hours, increased with increasing numbers of monocytes, and required mRNA and protein synthesis. Supernatant from HUVEC/monocyte coculture induced TF activity in HUVECs, but not in monocytes, indicating that HUVEC were the cells responsible for the activity, and that soluble mediators were involved. Interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α), well-known inducers of TF in HUVECs, were found in the supernatant from the coculture, and specific antibodies directed against either cytokine inhibited TF generation. The need of IL-1β and TNF-α synthesis in order to elicit TF expression was also suggested by the delay observed in TF mRNA formation and TF activity generation when monocytes were incubated with HUVECs. IL-1β and TNF-α antigen levels in the coculture supernatant, and, consequently, HUVEC TF expression, were inhibited in the presence of anti-CD18 monoclonal antibody. These findings emphasize the role of cell-cell contact and cross-talk in the procoagulant activity, which could be responsible for the thromboembolic complications observed in those vascular disorders in which monocyte infiltration is a common feature.

scholarly journals Flow mechanotransduction regulates traction forces, intercellular forces, and adherens junctions

2012 ◽  
Vol 302 (11) ◽  
pp. H2220-H2229 ◽  
Author(s):  
Lucas H. Ting ◽  
Jessica R. Jahn ◽  
Joon I. Jung ◽  
Benjamin R. Shuman ◽  
Shirin Feghhi ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Laminar Flow ◽  
Adherens Junctions ◽  
Cell Junctions ◽  
Flow Conditions ◽  
Traction Forces ◽  
Disturbed Flow ◽  
Cytoskeletal Tension ◽  
Static Conditions ◽  
Cell Cell

Endothelial cells respond to fluid shear stress through mechanotransduction responses that affect their cytoskeleton and cell-cell contacts. Here, endothelial cells were grown as monolayers on arrays of microposts and exposed to laminar or disturbed flow to examine the relationship among traction forces, intercellular forces, and cell-cell junctions. Cells under laminar flow had traction forces that were higher than those under static conditions, whereas cells under disturbed flow had lower traction forces. The response in adhesion junction assembly matched closely with changes in traction forces since adherens junctions were larger in size for laminar flow and smaller for disturbed flow. Treating the cells with calyculin-A to increase myosin phosphorylation and traction forces caused an increase in adherens junction size, whereas Y-27362 cause a decrease in their size. Since tugging forces across cell-cell junctions can promote junctional assembly, we developed a novel approach to measure intercellular forces and found that these forces were higher for laminar flow than for static or disturbed flow. The size of adherens junctions and tight junctions matched closely with intercellular forces for these flow conditions. These results indicate that laminar flow can increase cytoskeletal tension while disturbed flow decreases cytoskeletal tension. Consequently, we found that changes in cytoskeletal tension in response to shear flow conditions can affect intercellular tension, which in turn regulates the assembly of cell-cell junctions.

scholarly journals Thrombospondin-1, a natural inhibitor of angiogenesis, regulates platelet-endothelial cell adhesion molecule-1 expression and endothelial cell morphogenesis.

1997 ◽  
Vol 8 (7) ◽  
pp. 1329-1341 ◽  
Author(s):  
N Sheibani ◽  
P J Newman ◽  
W A Frazier
Keyword(s):  
Endothelial Cells ◽  
Cell Adhesion ◽  
Endothelial Cell ◽  
Adhesion Molecule ◽  
Cell Adhesion Molecule ◽  
Cell Contact ◽  
Platelet Endothelial Cell Adhesion ◽  
Cell Adhesion Molecule 1 ◽  
Endothelial Cell Adhesion ◽  
Cell Cell

Expression of thrombospondin-1 (TS1) in polyoma middle-sized T (tumor)-transformed mouse brain endothelial cells (bEND.3) restores a normal phenotype and suppresses their ability to form hemangiomas in mice. We show that TS1 expression results in complete suppression of platelet-endothelial cell adhesion molecule-1 (PECAM-1) expression and altered cell-cell interactions in bEND.3 cells. To further investigate the role of PECAM-1 in regulation of endothelial cell-cell interactions and morphogenesis, we expressed human (full length) or murine (delta 15) PECAM-1 isoforms in TS1-transfected bEND.3 (bEND/TS) cells. Expression of either human or murine PECAM-1 resulted in an enhanced ability to organize and form networks of cords on Matrigel, an effect that was specifically blocked by antibodies to PECAM-1. Anti-PECAM-1 antibodies also inhibited tube formation in Matrigel by normal human umbilical vein endothelial cells. However, PECAM-1-transfected bEND/TS cells did not regain the ability to form hemangiomas in mice and the expressed PECAM-1, unlike the endogenous PECAM-1 expressed in bEND.3 cells, failed to localize to sites of cell-cell contact. This may be, in part, attributed to the different isoforms of PECAM-1 expressed in bEND.3 cells. Using reverse transcription-polymerase chain reaction, we determined that bEND.3 cells express mRNA encoding six different PECAM-1 isoforms, the isoform lacking both exons 14 and 15 (delta 14&15) being most abundant. Expression of the murine delta 14&15 PECAM-1 isoform in bEND/TS cells resulted in a similar phenotype to that described for the full-length human or murine delta 15 PECAM-1 isoform. The delta 14&15 isoform, despite the lack of exon 14, failed to localize to sites of cell-cell contact even in clones that expressed it at very high levels. Thus, contrary to recent reports, lack of exon 14 is not sufficient to result in junctional localization of PECAM-1 isoforms in bEND/TS cells.

scholarly journals Vinculin controls endothelial cell junction dynamics during vascular lumen formation

2021 ◽  
Author(s):  
Maria P. Kotini ◽  
Miesje M. van der Stoel ◽  
Mitchell K. Han ◽  
Bettina Kirchmaier ◽  
Johan de Rooij ◽  
...  
Keyword(s):  
Endothelial Cell ◽  
Cell Junctions ◽  
Cell Junction ◽  
Vascular Integrity ◽  
Lumen Formation ◽  
Cell Behaviors ◽  
Sprouting Angiogenesis ◽  
Dynamic Cell ◽  
External Forces ◽  
Cell Cell

AbstractBlood vessel morphogenesis is driven by coordinated endothelial cell behaviors, which depend on dynamic cell-cell interactions. Remodeling of endothelial cell-cell junctions promote morphogenetic cellular events while preserving vascular integrity. Here, we have analyzed the dynamics of endothelial cell-cell junctions during lumen formation in angiogenic sprouts. By live-imaging of the formation of intersegmental blood vessels in zebrafish, we demonstrate that lumen expansion is accompanied by the formation of transient finger-shaped junctions. Formation and maintenance of these junctional fingers are positively regulated by blood pressure whereas inhibition of blood flow prevents their formation. Using fluorescent reporters, we show that the tension-sensor Vinculin localizes to junctional fingers. Furthermore, loss of vinculin function, in vinculin a and -b double knockouts, prevents junctional finger formation in angiogenic sprouts, whereas endothelial expression of a vinculin transgene is sufficient to restore junctional fingers. Taken together, our findings suggest a mechanism in which lumen expansion during angiogenesis leads to an increase in junctional tension, which triggers recruitment of vinculin and formation of junctional fingers. We propose that endothelial cells may employ force-dependent junctional remodeling to react to changes in external forces to protect cell-cell contacts and to maintain vascular integrity during sprouting angiogenesis.

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