scholarly journals MYADM controls endothelial barrier function through ERM-dependent regulation of ICAM-1 expression

2013 ◽  
Vol 24 (4) ◽  
pp. 483-494 ◽  
Author(s):  
Juan F. Aranda ◽  
Natalia Reglero-Real ◽  
Beatriz Marcos-Ramiro ◽  
Ana Ruiz-Sáenz ◽  
Laura Fernández-Martín ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Plasma Membrane ◽  
Inflammatory Response ◽  
Barrier Function ◽  
Leukocyte Adhesion ◽  
Cell Junctions ◽  
Membrane Domains ◽  
Filamentous Actin ◽  
Cytokine Tumor Necrosis Factor ◽  
Factor Α

The endothelium maintains a barrier between blood and tissue that becomes more permeable during inflammation. Membrane rafts are ordered assemblies of cholesterol, glycolipids, and proteins that modulate proinflammatory cell signaling and barrier function. In epithelial cells, the MAL family members MAL, MAL2, and myeloid-associated differentiation marker (MYADM) regulate the function and dynamics of ordered membrane domains. We analyzed the expression of these three proteins in human endothelial cells and found that only MYADM is expressed. MYADM was confined in ordered domains at the plasma membrane, where it partially colocalized with filamentous actin and cell–cell junctions. Small interfering RNA (siRNA)-mediated MYADM knockdown increased permeability, ICAM-1 expression, and leukocyte adhesion, all of which are features of an inflammatory response. Barrier function decrease in MYADM-silenced cells was dependent on ICAM-1 expression. Membrane domains and the underlying actin cytoskeleton can regulate each other and are connected by ezrin, radixin, and moesin (ERM) proteins. In endothelial cells, MYADM knockdown induced ERM activation. Triple-ERM knockdown partially inhibited ICAM-1 increase induced by MYADM siRNA. Importantly, ERM knockdown also reduced ICAM-1 expression in response to the proinflammatory cytokine tumor necrosis factor-α. MYADM therefore regulates the connection between the plasma membrane and the cortical cytoskeleton and so can control the endothelial inflammatory response.

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 L-Selectin–Dependent Leukocyte Adhesion to Microvascular But Not to Macrovascular Endothelial Cells of the Human Coronary System

Blood ◽  
1997 ◽  
Vol 89 (9) ◽  
pp. 3228-3235 ◽  
Author(s):  
A. Zakrzewicz ◽  
M. Gräfe ◽  
D. Terbeek ◽  
M. Bongrazio ◽  
W. Auch-Schwelk ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Time Course ◽  
Leukocyte Adhesion ◽  
Flow Chamber ◽  
Shear Stresses ◽  
Selectin Ligands ◽  
Tnf Α ◽  
Factor Α

Abstract To characterize L-selectin–dependent cell adhesion to human vascular endothelium, human cardiac microvascular endothelial cells (HCMEC) and human coronary endothelial cells (HCEC) were isolated from explanted human hearts. The adhesion behavior of human (NALM-6) and mouse (300.19) pre-B cells transfected with cDNA encoding for human L-selectin was compared with that of the respective nontransfected cells in a flow chamber in vitro. More than 80% of the adhesion to tumor necrosis factor-α (TNF-α)–stimulated HCMEC at shear stresses <2 dyne/cm2 was L-selectin dependent and could be equally well blocked by an anti–L-selectin antibody or a L-selectin-IgG-chimera. No L-selectin dependent adhesion to HCEC could be shown. The L-selectin dependent adhesion to HCMEC was insensitive to neuraminidase, but greatly inhibited by addition of NaClO3 , which inhibits posttranslational sulfation and remained elevated for at least 24 hours of stimulation. E-selectin dependent adhesion of HL60 cells to HCMEC was blocked by neuraminidase, but not by NaClO3 and returned to control levels within 18 hours of HCMEC stimulation. It is concluded that microvascular, but not macrovascular endothelial cells express TNF-α–inducible sulfated ligand(s) for L-selectin, which differ from known L-selectin ligands, because sialylation is not required. The prolonged time course of L-selectin dependent adhesion suggests a role in sustained leukocyte recruitment into inflammatory sites in vivo.

scholarly journals TRPC6 is the endothelial calcium channel that regulates leukocyte transendothelial migration during the inflammatory response

2015 ◽  
Vol 212 (11) ◽  
pp. 1883-1899 ◽  
Author(s):  
Evan W. Weber ◽  
Fei Han ◽  
Mohammad Tauseef ◽  
Lutz Birnbaumer ◽  
Dolly Mehta ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Inflammatory Response ◽  
Calcium Channel ◽  
Transient Receptor Potential ◽  
Leukocyte Adhesion ◽  
Transendothelial Migration ◽  
Dominant Negative ◽  
Ion Concentration ◽  
Free Calcium ◽  
Leukocyte Transendothelial Migration

Leukocyte transendothelial migration (TEM) is a tightly regulated, multistep process that is critical to the inflammatory response. A transient increase in endothelial cytosolic free calcium ion concentration (↑[Ca2+]i) is required for TEM. However, the mechanism by which endothelial ↑[Ca2+]i regulates TEM and the channels mediating this ↑[Ca2+]i are unknown. Buffering ↑[Ca2+]i in endothelial cells does not affect leukocyte adhesion or locomotion but selectively blocks TEM, suggesting a role for ↑[Ca2+]i specifically for this step. Transient receptor potential canonical 6 (TRPC6), a Ca2+ channel expressed in endothelial cells, colocalizes with platelet/endothelial cell adhesion molecule-1 (PECAM) to surround leukocytes during TEM and clusters when endothelial PECAM is engaged. Expression of dominant-negative TRPC6 or shRNA knockdown in endothelial cells arrests neutrophils apically over the junction, similar to when PECAM is blocked. Selectively activating endothelial TRPC6 rescues TEM during an ongoing PECAM blockade, indicating that TRPC6 functions downstream of PECAM. Furthermore, endothelial TRPC6 is required for trafficking of lateral border recycling compartment membrane, which facilitates TEM. Finally, mice lacking TRPC6 in the nonmyeloid compartment (i.e., endothelium) exhibit a profound defect in neutrophil TEM with no effect on leukocyte trafficking. Our findings identify endothelial TRPC6 as the calcium channel mediating the ↑[Ca2+]i required for TEM at a step downstream of PECAM homophilic interactions.

P4501Identification and characterization of endothelial microRNAs that modulate leukocyte adhesion through novel mechanistic pathways

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
H Giral Arnal ◽  
A Kratzer ◽  
M Moobed ◽  
U Landmesser
Keyword(s):  
Myocardial Infarction ◽  
Endothelial Cells ◽  
Cell Adhesion ◽  
Endothelial Cell ◽  
Barrier Function ◽  
Leukocyte Adhesion ◽  
Endothelial Barrier ◽  
Monocyte Adhesion ◽  
Endothelial Barrier Function ◽  
Ras Gtpase

Abstract Introduction Inflammation is essential for the protective response of the immune system. However, hyperactivated inflammation and dysregulated resolution strongly associates with the pathophysiology of atherosclerosis and ischemia-induced injury after myocardial infarction. Therefore, attenuation of inflammatory response has emerged as a promising approach to reduce cardiovascular disease burden. A limiting step of inflammation is the local recruitment of leukocytes to the lesion, a process regulated by intense cross-talk between immune and endothelial cells. A better understanding of the modulatory mechanisms of adhesion is paramount for the development of better therapies. Purpose Identify endothelial miRNAs that impact leukocyte adhesion and characterize the underlying pathways that regulate this process. Methods A functional high-throughput screening (HTS) of human miRNA libraries (mimics and inhibitors) measured miRNA impact on monocyte (THP-1) adhesion to an endothelial monolayer (HAEC). Individually miRNAs were transfected in HAEC and fluorescently-labeled monocyte attachment was recorded by a robotic automated microscopy platform. Computational analysis lead to identification of potential targets and relevant pathways associated to the action of candidate miRNAs. Further validation of promising targets was performed by qPCR and western blotting. Additional endothelial phenotypic properties such as cytoskeleton morphology or endothelial barrier function were analyzed in the presence of specific miRNAs. Results Functional HTS and secondary screening resulted in 38 microRNAs that reduced and 2 that increased monocyte adhesion. Bioinformatic target prediction and pathway analysis narrowed the set of miRNA candidates used for characterization studies. These miRNAs significantly modulated cell adhesion of both monocytic-leukemia THP-1 cells and freshly isolated human CD14+ monocytes, but effect on CD14+ was weaker compared to THP-1. Several miRNAs induced severe changes on endothelial cell morphology, likely due to cytoskeleton rearrangement. We identified and validated several miRNA targets belonging to the Ras GTPase family of actin remodeling modulators (RalA, RAP1A). Additionally, a few miRNAs targeted Ephrin signaling molecules (EFNs, EPHs) which mediate multiple cell functions including cell-cell contacts. We also explored miRNA effects on endothelial barrier function and measured monocyte adhesion under physiological and disturbed flow conditions. Conclusions We identified a set of miRNAs able to modulate monocyte cell adhesion to endothelial cells under inflammatory conditions. Potential mechanistic pathways of miRNA modulation of adhesion included Ephrin signaling pathway and Ras GTPase family. A better understanding of the role of specific microRNAs regulating the immune-endothelial cell interaction may lead to novel therapeutic strategies in atherosclerosis and myocardial infarction. Acknowledgement/Funding DZHK (German Centre for Cardiovascular Research), partner site Berlin, Germany; Berlin Institute of Health (BIH)

scholarly journals Sinusoidal Endotheliopathy in Nonalcoholic Steatohepatitis: Therapeutic Implications

2021 ◽  
Author(s):  
Samar H Ibrahim
Keyword(s):  
Endothelial Cells ◽  
Inflammatory Response ◽  
Adhesion Molecules ◽  
Immune Cells ◽  
Immune Cell ◽  
Leukocyte Adhesion ◽  
Low Flow ◽  
Liver Sinusoidal Endothelial Cells ◽  
Nonalcoholic Fatty Liver ◽  
Therapeutic Implications

Liver sinusoidal endothelial cells (LSEC) are distinct subtypes of endothelial cells lining a low flow vascular bed at the interface of the liver parenchyma, and the circulating immune cells and soluble factors. Emerging literature implicates LSEC in the pathogenesis and progression of nonalcoholic fatty liver disease (NAFLD). During the evolution of NAFLD, LSEC dysfunction ensues. LSEC undergo morphological and functional transformation known as "capillarization", as well as a pathogenic increase in surface adhesion molecules expression, referred to in this review as "endotheliopathy". LSEC govern the composition of hepatic immune cell populations in nonalcoholic steatohepatis (NASH) by mediating leukocyte subset adhesion through specific combinations of activated adhesion molecules and secreted chemokines. Moreover, extracellular vesicles released by hepatocyte under lipotoxic stress in NASH act as a catalyst for the inflammatory response and promote immune cell chemotaxis and adhesion. In the current review, we highlight leukocyte adhesion to LSEC as an initiating event in the sterile inflammatory response in NASH. We discuss preclinical studies targeting immune cells adhesion in NASH mouse models, and potential therapeutic anti-inflammatory strategies for human NASH.

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