Modeling the three-way feedback between cellular contractility, actin polymerization, and adhesion turnover resolves the contradictory effects of RhoA and Rac1 on endothelial junction dynamics

The formation and recovery of gaps in the vascular endothelium governs a wide range of physiological and pathological phenomena, from angiogenesis to atherosclerosis and tumor cell extravasation. However, the interplay between the mechanical and signaling processes that drive dynamic behavior in vascular endothelial cells is not well understood. In this study, we propose a chemo-mechanical model to investigate the maintenance of endothelial junctions as dependent on the crosstalk between actomyosin contractility, VE-cadherin bond turnover, and actin polymerization, which mediate the forces exerted on the cell-cell interface. Our theoretical model reveals that active cell tension can stabilize cadherin bonds within an adhesion, but excessive RhoA signaling can drive bond dissociation and junction failure. While Rac1-mediated actin polymerization aids gap closure, high levels of Rac1 may also facilitate junction weakening. Combining the modeling framework with novel experiments, we identify how dynamic rupture and heal cycles emerge and, further, describe why gaps tend to localize at multi-cell contacts. Beyond, our analysis also indicates that a critical balance between RhoA and Rac1 expression is required to maintain junction stability and limit endothelial dysfunction. The model predicts how pharmacological modulation of actin polymerization and cell contractility impacts junction stability, with predictions subsequently validated experimentally. Our proposed framework can help guide the development of therapeutics that target the Rho family of GTPases and downstream active mechanical processes.

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TRPM7 regulates vascular endothelial cell adhesion and tube formation

AJP Cell Physiology ◽

10.1152/ajpcell.00275.2013 ◽

2015 ◽

Vol 308 (4) ◽

pp. C308-C318 ◽

Cited By ~ 19

Author(s):

Zhao Zeng ◽

Koichi Inoue ◽

Huawei Sun ◽

Tiandong Leng ◽

Xuechao Feng ◽

...

Keyword(s):

Endothelial Cells ◽

Cell Adhesion ◽

Transient Receptor Potential ◽

Vascular Endothelial Cells ◽

Vascular Endothelial Cell ◽

Underlying Mechanism ◽

Tube Formation ◽

Vascular Endothelial ◽

Cell Contractility ◽

Transient Receptor Potential Melastatin

Transient receptor potential melastatin 7 (TRPM7) is a nonselective cation channel with an α-kinase domain in its COOH terminal, known to play a role in diverse physiological and pathological processes such as Mg2+ homeostasis, cell proliferation, and hypoxic neuronal injury. Increasing evidence suggests that TRPM7 contributes to the physiology/pathology of vascular systems. For example, we recently demonstrated that silencing TRPM7 promotes growth and proliferation and protects against hyperglycemia-induced injury in human umbilical vein endothelial cells (HUVECs). Here we investigated the potential effects of TRPM7 on morphology, adhesion, migration, and tube formation of vascular endothelial cells and the potential underlying mechanism. We showed that inhibition of TRPM7 function in HUVECs by silencing TRPM7 decreases the density of TRPM7-like current and cell surface area and inhibits cell adhesion to Matrigel. Silencing TRPM7 also promotes cell migration, wound healing, and tube formation. Further studies showed that the extracellular signal-regulated kinase (ERK) pathway is involved in the change of cell morphology and the increase in HUVEC migration induced by TRPM7 silencing. We also demonstrated that silencing TRPM7 enhances the phosphorylation of myosin light chain (MLC) in HUVECs, which might be involved in the enhancement of cell contractility and motility. Collectively, our data suggest that the TRPM7 channel negatively regulates the function of vascular endothelial cells. Further studies on the underlying mechanism may facilitate the development of the TRPM7 channel as a target for the therapeutic intervention of vascular diseases.

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An In Vitro Model of Diabetic Retinal Vascular Endothelial Dysfunction and Neuroretinal Degeneration

Journal of Diabetes Research ◽

10.1155/2021/9765119 ◽

2021 ◽

Vol 2021 ◽

pp. 1-12

Author(s):

Qiyun Wang ◽

Xinyuan Zhang ◽

Kaiyue Wang ◽

Ling Zhu ◽

Bingjie Qiu ◽

...

Keyword(s):

Cell Proliferation ◽

Endothelial Dysfunction ◽

Vascular Endothelial Cells ◽

Tube Formation ◽

Cell Counting ◽

Vascular Endothelial ◽

Migration Assay ◽

Tube Formation Assay ◽

Wide Range

Background. Diabetic retinopathy (DR) is a leading cause of blindness in working-age populations. Proper in vitro DR models are crucial for exploring pathophysiology and identifying novel therapeutic targets. This study establishes a rational in vitro diabetic retinal neuronal-endothelial dysfunction model and a comprehensive downstream validation system. Methods. Human retinal vascular endothelial cells (HRMECs) and retinal ganglion cells (RGCs) were treated with different glucose concentrations with mannitol as matched osmotic controls. Cell proliferation and viability were evaluated by the Cell Counting Kit-8. Cell migration was measured using a transwell migration assay. Cell sprouting was assessed by a tube formation assay. The VEGF expression was assessed by ELISA. RGCs were labeled by neurons and RGC markers TUJ1 and BRN3A for quantitative and morphological analysis. Apoptosis was detected using PI/Hoechst staining and TUNEL assay and quantified by ImageJ. Results. Cell proliferation and migration in HRMECs were significantly higher in the 25 mM glucose-treated group ( p < 0.001 ) but lower in the 50 mM and 100 mM groups ( p < 0.001 ). The permeability and the apoptotic index in HRMECs were statistically higher in the 25 mM, 50 mM, and 100 mM groups ( p < 0.05 ). The tube formation assay found that all the parameters were significantly higher in the 25 mM and 50 mM groups ( p < 0.001 ) concomitant with the elevated VEGFA expression in HRMECs ( p = 0.016 ). Cell viability was significantly lower in the 50 mM, 100 mM, and 150 mM groups in RGCs ( p 50 mM = 0.013 , p 100 mM = 0.019 , and p 150 mM = 0.002 ). Apoptosis was significantly elevated, but the proportion of RGCs with neurite extension was significantly lower in the 50 mM, 100 mM, and 150 mM groups ( p 50 mM < 0.001 , p 100 m M < 0.001 , and p 150 mM < 0.001 ). Conclusions. We have optimized glucose concentrations to model diabetic retinal endothelial (25-50 mM) or neuronal (50-100 mM) dysfunction in vitro, which have a wide range of downstream applications.

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Natural History of the Bruise: Formation, Elimination, and Biological Effects of Oxidized Hemoglobin

Oxidative Medicine and Cellular Longevity ◽

10.1155/2013/703571 ◽

2013 ◽

Vol 2013 ◽

pp. 1-9 ◽

Cited By ~ 28

Author(s):

Viktória Jeney ◽

John W. Eaton ◽

György Balla ◽

József Balla

Keyword(s):

Actin Polymerization ◽

Vascular Endothelial Cells ◽

Biological Effects ◽

Scavenger Receptor ◽

Oxidation States ◽

Vascular Endothelial ◽

Disease States ◽

Macrophage Scavenger Receptor ◽

Single Chemical ◽

History Of

Numerous disease states are associated with hemolysis or hemorrhage. Because red cells in the extravascular space tend to lyse quickly, hemoglobin (Hb) is released and is prone to autoxidation producing MetHb. Inorganic and organic peroxides may convert Hb and MetHb to higher oxidation states such as ferrylHb. FerrylHb is not a single chemical entity but is a mixture of globin- and porphyrin-centered radicals and covalently cross-linked Hb multimers. Oxidized Hb species are potent prooxidants caused mainly by heme release from oxidized Hb. Moreover, ferrylHb is a strong proinflammatory agonist that targets vascular endothelial cells. This proinflammatory effect of ferrylHb requires actin polymerization, is characterized by the upregulation of proinflammatory adhesion molecules, and is independent of heme release. Deleterious effects of native Hb are controlled by haptoglobin (Hp) that binds cell-free Hb avidly and facilitates its removal from circulation through the CD163 macrophage scavenger receptor-mediated endocytosis. Under circumstances of Hb oxidation, Hp can prevent heme release from MetHb, but unfortunately the Hp-mediated removal of Hb is severely compromised when Hb is structurally altered such as in ferrylHb allowing deleterious downstream reactions to occur even in the presence of Hp.

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Contributions of Microscopy to the Diagnosis and Investigation of Aids-Associated Renal Disease

Microscopy and Microanalysis ◽

10.1017/s1431927600018791 ◽

1999 ◽

Vol 5 (S2) ◽

pp. 1094-1095

Author(s):

D. N. Howell ◽

L. A. Szczech

Keyword(s):

Hiv Infection ◽

Vascular Endothelial Cells ◽

Microscopic Analysis ◽

Renal Tissue ◽

Nuclear Bodies ◽

Mononuclear Leukocytes ◽

Renal Lesion ◽

Vascular Endothelial ◽

Wide Range ◽

Tubuloreticular Inclusions

Microscopy has had a major role in the analysis of renal disorders associated with human immunodeficiency virus (HIV) infection, both as a diagnostic method and as a means of studying pathogenic mechanisms. In the diagnostic realm, microscopic analysis of renal tissue obtained at biopsy and autopsy is a mainstay for the detection of a wide range of glomerular, vascular, and tubulointerstitial diseases. As an investigative tool, microscopy has made an important, albeit somewhat controversial, contribution to our understanding of the pathogenesis of at least one HIV-associated renal lesion.A variety of ultrastructural alterations have been documented in association with HIV infection. These include tubuloreticular inclusions (most commonly seen in vascular endothelial cells and mononuclear leukocytes)(Fig. la), cylindrical confronting cisternae (typically found in mononuclear leukocytes) (Fig. lb), and nuclear abnormalities such as nuclear bodies and granular change (most often in tubulointerstitial cells) (Fig. lc).

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CD147 (BSG) but not ACE2 expression is detectable in vascular endothelial cells within single cell RNA sequencing datasets derived from multiple tissues in healthy individuals

10.1101/2020.05.29.123513 ◽

2020 ◽

Cited By ~ 3

Author(s):

C Ganier ◽

X Du-Harpur ◽

N Harun ◽

B Wan ◽

C Arthurs ◽

...

Keyword(s):

Endothelial Cells ◽

Single Cell ◽

Vascular Endothelial Cells ◽

Cell Surface Receptor ◽

Vascular Endothelial ◽

Healthy Individuals ◽

Sequencing Data ◽

Direct Role ◽

Single Cell Sequencing ◽

Wide Range

ABSTRACTCoronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and is associated with a wide range of systemic manifestations. Several observations support a role for vascular endothelial dysfunction in the pathogenesis including an increased incidence of thrombotic events and coagulopathy and the presence of vascular risk factors as an independent predictor of poor prognosis. It has recently been reported that endothelitis is associated with viral inclusion bodies suggesting a direct role for SARS-CoV-2 in the pathogenesis. The ACE2 receptor has been shown to mediate SARS-CoV-2 uptake and it has been proposed that CD147 (BSG) can function as an alternative cell surface receptor. To define the endothelial cell populations that are susceptible to infection with SARS-CoV-2, we investigated the expression of ACE2 as well as other genes implicated in the cellular entry of SARS-Cov-2 in the vascular endothelium through the analysis of single cell sequencing data derived from multiple human tissues (skin, liver, kidney, lung and intestine). We found that CD147 (BSG) but not ACE2 is detectable in vascular endothelial cells within single cell sequencing datasets derived from multiple tissues in healthy individuals. This implies that either ACE2 is not expressed in healthy tissue but is instead induced in response to SARS-Cov2 or that SARS-Cov2 enters endothelial cells via an alternative receptor such as CD147.

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Cytoskeletal Remodeling Mimics Endothelial Response to Microgravity

Frontiers in Cell and Developmental Biology ◽

10.3389/fcell.2021.733573 ◽

2021 ◽

Vol 9 ◽

Author(s):

Laura Locatelli ◽

Jeanette A. M. Maier

Keyword(s):

Endothelial Cells ◽

Stress Response ◽

Actin Polymerization ◽

Simulated Microgravity ◽

Transient Receptor Potential ◽

Vascular Endothelial Cells ◽

Cytochalasin D ◽

Endothelial Cell Proliferation ◽

Vascular Endothelial ◽

Transient Receptor Potential Melastatin

Mechanical cues contribute to the maintenance of a healthy endothelium, which is essential for vascular integrity. Indeed endothelial cells are mechanosensors that integrate the forces in the form of biochemical signals. The cytoskeleton is fundamental in sensing mechanical stimuli and activating specific signaling pathways. Because the cytoskeleton is very rapidly remodeled in endothelial cells exposed to microgravity, we investigated whether the disruption of actin polymerization by cytochalasin D in 1g condition triggers and orchestrates responses similar to those occurring in micro- and macro-vascular endothelial cells upon gravitational unloading. We focused our attention on the effect of simulated microgravity on stress proteins and transient receptor potential melastatin 7 (TRPM7), a cation channel that acts as a mechanosensor and modulates endothelial cell proliferation and stress response. Simulated microgravity downregulates TRPM7 in both cell types. However, 24 h of treatment with cytochalasin D decreases the amounts of TRPM7 only in macrovascular endothelial cells, suggesting that the regulation and the role of TRPM7 in microvascular cells are more complex than expected. The 24 h culture in the presence of cytochalasin D mimics the effect of simulated microgravity in modulating stress response in micro- and macro-vascular endothelial cells. We conclude that cytoskeletal disruption might mediate some effects of microgravity in endothelial cells.

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