scholarly journals High Mobility Group Box 1 Mediates TMAO-Induced Endothelial Dysfunction

2019 ◽  
Vol 20 (14) ◽  
pp. 3570 ◽  
Author(s):  
Gurinder Bir Singh ◽  
Yang Zhang ◽  
Krishna M. Boini ◽  
Saisudha Koka
Keyword(s):  
Endothelial Cells ◽  
Endothelial Dysfunction ◽  
High Mobility ◽  
Prior Treatment ◽  
Cell Junctions ◽  
High Mobility Group ◽  
Cell Junction ◽  
Tlr4 Expression ◽  
Junction Proteins ◽  
Cell Cell

The intestinal microbe-derived metabolite trimethylamine N-oxide (TMAO) is implicated in the pathogenesis of cardiovascular diseases (CVDs). The molecular mechanisms of how TMAO induces atherosclerosis and CVDs’ progression are still unclear. In this regard, high-mobility group box protein 1 (HMGB1), an inflammatory mediator, has been reported to disrupt cell–cell junctions, resulting in vascular endothelial hyper permeability leading to endothelial dysfunction. The present study tested whether TMAO associated endothelial dysfunction results via HMGB1 activation. Biochemical and RT-PCR analysis showed that TMAO increased the HMGB1 expression in a dose-dependent manner in endothelial cells. However, prior treatment with glycyrrhizin, an HMGB1 binder, abolished the TMAO-induced HMGB1 production in endothelial cells. Furthermore, Western blot and immunofluorescent analysis showed significant decrease in the expression of cell–cell junction proteins ZO-2, Occludin, and VE-cadherin in TMAO treated endothelial cells compared with control cells. However, prior treatment with glycyrrhizin attenuated the TMAO-induced cell–cell junction proteins’ disruption. TMAO increased toll-like receptor 4 (TLR4) expression in endothelial cells. Inhibition of TLR4 expression by TLR4 siRNA protected the endothelial cells from TMAO associated tight junction protein disruption via HMGB1. In conclusion, our results demonstrate that HMGB1 is one of the important mediators of TMAO-induced endothelial dysfunction.

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 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 The Motor Protein Myosin-X Transports VE-Cadherin along Filopodia To Allow the Formation of Early Endothelial Cell-Cell Contacts

2010 ◽  
Vol 30 (7) ◽  
pp. 1703-1717 ◽  
Author(s):  
Sébastien Almagro ◽  
Claire Durmort ◽  
Adeline Chervin-Pétinot ◽  
Stephanie Heyraud ◽  
Mathilde Dubois ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Motor Protein ◽  
Vascular Diseases ◽  
Dominant Negative ◽  
Cell Junctions ◽  
Cell Junction ◽  
Dominant Negative Mutant ◽  
Myosin X ◽  
Actin Cables ◽  
Cell Cell

ABSTRACT Vascular endothelium (VE), the monolayer of endothelial cells that lines the vascular tree, undergoes damage at the basis of some vascular diseases. Its integrity is maintained by VE-cadherin, an adhesive receptor localized at cell-cell junctions. Here, we show that VE-cadherin is also located at the tip and along filopodia in sparse or subconfluent endothelial cells. We observed that VE-cadherin navigates along intrafilopodial actin filaments. We found that the actin motor protein myosin-X is colocalized and moves synchronously with filopodial VE-cadherin. Immunoprecipitation and pulldown assays confirmed that myosin-X is directly associated with the VE-cadherin complex. Furthermore, expression of a dominant-negative mutant of myosin-X revealed that myosin-X is required for VE-cadherin export to cell edges and filopodia. These features indicate that myosin-X establishes a link between the actin cytoskeleton and VE-cadherin, thereby allowing VE-cadherin transportation along intrafilopodial actin cables. In conclusion, we propose that VE-cadherin trafficking along filopodia using myosin-X motor protein is a prerequisite for cell-cell junction formation. This mechanism may have functional consequences for endothelium repair in pathological settings.

scholarly journals Golgi-associated cPLA2α Regulates Endothelial Cell–Cell Junction Integrity by Controlling the Trafficking of Transmembrane Junction Proteins

2009 ◽  
Vol 20 (19) ◽  
pp. 4225-4234 ◽  
Author(s):  
Elsa Regan-Klapisz ◽  
Vincent Krouwer ◽  
Miriam Langelaar-Makkinje ◽  
Laxman Nallan ◽  
Michael Gelb ◽  
...  
Keyword(s):  
Endothelial Cell ◽  
Intracellular Trafficking ◽  
Adherens Junction ◽  
Cell Junctions ◽  
Cell Junction ◽  
Tight Junction Formation ◽  
Junction Formation ◽  
Junction Proteins ◽  
Cell Cell

In endothelial cells specifically, cPLA2α translocates from the cytoplasm to the Golgi complex in response to cell confluence. Considering the link between confluence and cell–cell junction formation, and the emerging role of cPLA2α in intracellular trafficking, we tested whether Golgi-associated cPLA2α is involved in the trafficking of junction proteins. Here, we show that the redistribution of cPLA2α from the cytoplasm to the Golgi correlates with adherens junction maturation and occurs before tight junction formation. Disruption of adherens junctions using a blocking anti-VE-cadherin antibody reverses the association of cPLA2α with the Golgi. Silencing of cPLA2α and inhibition of cPLA2α enzymatic activity using various inhibitors result in the diminished presence of the transmembrane junction proteins VE-cadherin, occludin, and claudin-5 at cell–cell contacts, and in their accumulation at the Golgi. Altogether, our data support the idea that VE-cadherin triggers the relocation of cPLA2α to the Golgi and that in turn, Golgi-associated cPLA2α regulates the transport of transmembrane junction proteins through or from the Golgi, thereby controlling the integrity of endothelial cell–cell junctions.

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.

Histidine-Rich Glycoprotein Inhibits High Mobility Group Box 1-Mediated Pathways in Vascular Endothelial Cells

2019 ◽  
Author(s):  
Shangze Gao ◽  
Hidenori Wake ◽  
Masakiyo Sakaguchi ◽  
Dengli Wang ◽  
Youhei Takahashi ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Vascular Endothelial Cells ◽  
High Mobility ◽  
High Mobility Group ◽  
Vascular Endothelial

Glycocalyx modulates the motility and proliferative response of vascular endothelium to fluid shear stress

2007 ◽  
Vol 293 (2) ◽  
pp. H1023-H1030 ◽  
Author(s):  
Yu Yao ◽  
Aleksandr Rabodzey ◽  
C. Forbes Dewey
Keyword(s):  
Endothelial Cells ◽  
Vascular Endothelium ◽  
Fluid Shear Stress ◽  
Vascular Endothelial Cells ◽  
Surface Profile ◽  
Cell Junctions ◽  
Vascular Endothelial ◽  
Fluid Shear ◽  
New Perspective ◽  
Cell Cell

Flow-induced mechanotransduction in vascular endothelial cells has been studied over the years with a major focus on putative connections between disturbed flow and atherosclerosis. Recent studies have brought in a new perspective that the glycocalyx, a structure decorating the luminal surface of vascular endothelium, may play an important role in the mechanotransduction. This study reports that modifying the amount of the glycocalyx affects both short-term and long-term shear responses significantly. It is well established that after 24 h of laminar flow, endothelial cells align in the direction of flow and their proliferation is suppressed. We report here that by removing the glycocalyx by using the specific enzyme heparinase III, endothelial cells no longer align under flow after 24 h and they proliferate as if there were no flow present. In addition, confluent endothelial cells respond rapidly to flow by decreasing their migration speed by 40% and increasing the amount of vascular endothelial cadherin in the cell-cell junctions. These responses are not observed in the cells treated with heparinase III. Heparan sulfate proteoglycans (a major component of the glycocalyx) redistribute after 24 h of flow application from a uniform surface profile to a distinct peripheral pattern with most molecules detected above cell-cell junctions. We conclude that the presence of the glycocalyx is necessary for the endothelial cells to respond to fluid shear, and the glycocalyx itself is modulated by the flow. The redistribution of the glycocalyx also appears to serve as a cell-adaptive mechanism by reducing the shear gradients that the cell surface experiences.

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 TNF-α Activates High-Mobility Group Box 1 - Toll-Like Receptor 4 Signaling Pathway in Human Aortic Endothelial Cells

2016 ◽  
Vol 38 (6) ◽  
pp. 2139-2151 ◽  
Author(s):  
Won Seok Yang ◽  
Nam Jeong Han ◽  
Jin Ju Kim ◽  
Mee Jeong Lee ◽  
Su-Kil Park
Keyword(s):  
Signal Transduction ◽  
Endothelial Cells ◽  
High Mobility ◽  
Neutralizing Antibody ◽  
High Mobility Group ◽  
Toll Like Receptor ◽  
Toll Like Receptor 4 ◽  
Aortic Endothelial Cells ◽  
Tnf Α ◽  
Human Aortic Endothelial Cells

Background/Aims: Toll-like receptor 4 (TLR4) interacts with endogenous substances as well as lipopolysaccharide. We explored whether TLR4 is implicated in tumor necrosis factor-α (TNF-α) signal transduction in human aortic endothelial cells. Methods: The pathway was evaluated by transfection of siRNAs, immunoprecipitation and Western blot analysis. Results: TNF-α activated spleen tyrosine kinase (Syk) within 10 min, which led to endothelin-1 (ET-1) production. TLR4 was also rapidly activated by TNF-α stimulation, as shown by recruitment of interleukin-1 receptor-associated kinase 1 to TLR4 and its adaptor molecule, myeloid differentiation factor 88 (MyD88). siRNA depletion of TLR4 markedly attenuated TNF-α-induced Syk activation and ET-1 production. TLR4 inhibitor (CLI-095), TLR4-neutralizing antibody and siRNA depletion of MyD88 also attenuated TNF-α-induced Syk activation. Syk was co-immunoprecipitated with TLR4, and TNF-α activated Syk bound to TLR4. High-mobility group box 1 (HMGB1) was rapidly released and associated with TLR4 after TNF-α stimulation with a peak at 5 min, which was prevented by N-acetylcysteine, an antioxidant. Glycyrrhizin (HMGB1 inhibitor), HMGB1-neutralizing antibody and siRNA depletion of HMGB1 all suppressed TNF-α-induced Syk activation and ET-1 production. Conclusion: Upon TNF-α stimulation, TLR4 is activated by HMGB1 that is immediately released after the generation of reactive oxygen species, and plays a crucial role in the signal transduction.

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