Induction Of Endothelial Adhesion Molecules Research Articles

SARS-CoV-2 Infection of Airway Epithelium Triggers Pulmonary Endothelial Cell Activation and Senescence Associated with Type I IFN Production.

Airway epithelial cells represent the main target of SARS-CoV-2 replication but several pieces of evidence suggest that endothelial cells (ECs), lining pulmonary blood vessels, are key players in lung injury in COVID-19 patients. Although in vivo evidence of SARS-CoV-2 affecting the vascular endothelium exists, in vitro data are limited. In the present study, we set up an organotypic model to dissect the crosstalk between airway epithelium and pulmonary endothelial cells during SARS-CoV-2 infection. We showed that SARS-CoV-2 infected airway epithelium triggers the induction of endothelial adhesion molecules in ECs, suggesting a bystander effect of dangerous soluble signals from the infected epithelium. The endothelial activation was correlated with inflammatory cytokines (IL-1β, IL-6, IL-8) and with the viral replication in the airway epithelium. Interestingly, SARS-CoV-2 infection determined a modulation of endothelial p21, which could be partially reversed by inhibiting IFN-β production from ECs when co-cultured with HAE. Altogether, we demonstrated that SARS-CoV-2 infected epithelium triggers activation/senescence processes in ECs involving type I IFN-β production, suggesting possible antiviral/damage mechanisms occurring in the endothelium.

Deletion of BACH1 Attenuates Atherosclerosis by Reducing Endothelial Inflammation.

The transcription factor BACH1 (BTB and CNC homology 1) suppressed endothelial cells (ECs) proliferation and migration and impaired angiogenesis in the ischemic hindlimbs of adult mice. However, the role and underlying mechanisms of BACH1 in atherosclerosis remain unclear. Mouse models of atherosclerosis in endothelial cell (EC)-specific-Bach1 knockout mice were used to study the role of BACH1 in the regulation of atherogenesis and the underlying mechanisms. Genetic analyses revealed that coronary artery disease-associated risk variant rs2832227 was associated with BACH1 gene expression in carotid plaques from patients. BACH1 was upregulated in ECs of human and mouse atherosclerotic plaques. Endothelial Bach1 deficiency decreased turbulent blood flow- or western diet-induced atherosclerotic lesions, macrophage content in plaques, expression of endothelial adhesion molecules (ICAM1 [intercellular cell adhesion molecule-1] and VCAM1 [vascular cell adhesion molecule-1]), and reduced plasma TNF-α (tumor necrosis factor-α) and IL-1β levels in atherosclerotic mice. BACH1 deletion or knockdown inhibited monocyte-endothelial adhesion and reduced oscillatory shear stress or TNF-α-mediated induction of endothelial adhesion molecules and/or proinflammatory cytokines in mouse ECs, human umbilical vein ECs, and human aortic ECs. Mechanistic studies showed that upon oscillatory shear stress or TNF-α stimulation, BACH1 and YAP (yes-associated protein) were induced and translocated into the nucleus in ECs. BACH1 upregulated YAP expression by binding to the YAP promoter. BACH1 formed a complex with YAP inducing the transcription of adhesion molecules. YAP overexpression in ECs counteracted the antiatherosclerotic effect mediated by Bach1-deletion in mice. Rosuvastatin inhibited BACH1 expression by upregulating microRNA let-7a in ECs, and decreased Bach1 expression in the vascular endothelium of hyperlipidemic mice. BACH1 was colocalized with YAP, and the expression of BACH1 was positively correlated with YAP and proinflammatory genes, as well as adhesion molecules in human atherosclerotic plaques. These data identify BACH1 as a mechanosensor of hemodynamic stress and reveal that the BACH1-YAP transcriptional network is essential to vascular inflammation and atherogenesis. BACH1 shows potential as a novel therapeutic target in atherosclerosis.

The Critical Role of SENP1‐Mediated GATA2 DeSUMOylation in Graft Arteriosclerosis by Promoting Endothelial Activation

Immune rejection mediated graft arteriosclerosis (GA) is the major cause of graft failure after allograft transplantation. The pathological process of GA starts from endothelial cell (EC) activation marked with inducible expression of endothelial adhesion molecules, which results in neointima formation, vasomotor dysfunction and consequent vascular occlusion. However, the comprehensive regulatory mechanism of EC activation during GA remains unclear. In the current study, dramatic but endothelium‐specific induction of SENP1, the major protease of small ubiquitin‐like modifier (SUMO) system, was observed in clinical graft rejection specimens by immunofluorescence staining, synchronized with endothelial activation mediated vascular remodeling. Of note, GATA2, the master transcriptional factor regulating expression of adhesion molecules, had similar expression pattern as SENP1. According to the correlation of endothelial SENP1 in GA, SENP1 endothelial conditional knockout mice (SENP1‐ecKO) were generated and subjected to an aorta transplantation model of GA. Endothelial SENP1 deficient graft maintained a better vessel function and had limited leukocyte recruitment and neointima formation during GA progression. Induction of endothelial adhesion molecules in early stages of GA was clearly diminished in the absence of endothelial SENP1 and this effect was confirmed in cultured mice aortic ECs as well as human EC bearing SENP1 deSUMOylase inactive mutant, indicating the regulatory effect of SUMOylation on EC activation. Indeed, constitutive SUMOylation of endothelial GATA2 was identified in SENP1‐ecKO graft and cultured EC, which was directly mediated by inflammation induced SENP1. Mechanistically, SUMOylated GATA2 demonstrated weakened stability and DNA binding onto promoters of adhesion molecule genes, resulting in dampened EC activation and consequently leukocyte‐endothelial adhesion and transmigration. More importantly, endothelial overexpression of GATA2 reversed the retarded GA progression in SENP1‐ecKO graft, further supporting the critical axis of SENP1‐GATA2 in endothelial inflammation. Taken together, we conclude that inflammation mediated SENP1 boosts GA by regulating GATA2 SUMOylation and consequent EC dysfunction.Support or Funding InformationThis work was supported by National Natural Science Foundation of China (Grant No. 81270357, 81422005 and 31470057), and Zhejiang Provincial Natural Science Foundation of China (Grant No. LR14H020002)

SOCS1 Prevents Graft Arteriosclerosis by Preserving Endothelial Cell Function

The aim of this study was to determine the role of suppressor of cytokine signaling 1 (SOCS1) in graft arteriosclerosis (GA). GA, the major cause of late cardiac allograft failure, is initiated by immune-mediated endothelial activation resulting in vascular inflammation and consequent neointima formation. SOCS1, a negative regulator of cytokine signaling, is highly expressed in endothelial cells (ECs) and may prevent endothelial inflammatory responses and phenotypic activation. Clinical specimens of coronary arteries with GA, with atherosclerosis, or without disease were collected for histological analysis. SOCS1 knockout or vascular endothelial SOCS1 (VESOCS1) transgenic mice were used in an aorta transplant model of GA. Mouse aortic ECs were isolated for in vitro assays. Dramatic but specific reduction of endothelial SOCS1 was observed in human GA and atherosclerosis specimens, which suggested the importance of SOCS1 in maintaining normal endothelial function. SOCS1 deletion in mice resulted in basal EC dysfunction. After transplantation, SOCS1-deficient aortic grafts augmented leukocyte recruitment and neointima formation, whereas endothelial overexpression of SOCS1 diminished arterial rejection. Induction of endothelial adhesion molecules in early stages of GA was suppressed by the VESOCS1 transgene, and this effect was confirmed in cultured aortic ECs. Moreover, VESOCS1 maintained better vascular function during GA progression. Mechanistically, endothelial SOCS1, by modulating both basal and cytokine-induced expression of the adhesion molecules platelet/endothelial cell adhesion molecule-1, intercellular adhesion molecule-1, and vascular cell adhesion molecule-1, restrained leukocyte adhesion and transendothelial migration during inflammatory cell infiltration. SOCS1 prevents GA progression by preserving endothelial function and attenuating cytokine-induced adhesion molecule expression in vascular endothelium.

Cutting Edge: TNF-Induced MicroRNAs Regulate TNF-Induced Expression of E-Selectin and Intercellular Adhesion Molecule-1 on Human Endothelial Cells: Feedback Control of Inflammation

MicroRNAs (miRNAs) pair with target sequences in the 3' untranslated region of mRNAs to posttranscriptionally repress gene expression. In this study, we report that TNF-mediated induction of endothelial adhesion molecules can be regulated by miRNAs that are induced by TNF. Specifically, E-selectin and ICAM-1 are targets of TNF-induced miRNAs miR-31 and miR-17-3p, respectively. Specific antagonism of these TNF-induced miRNAs increased neutrophil adhesion to cultured endothelial cells. Conversely, transfections with mimics of these miRNAs decreased neutrophil adhesion to endothelial cells. These data suggest that miRNAs provide negative feedback control of inflammation.

Sphingosine Kinase-1 Associates with Integrin α Vβ 3 to Mediate Endothelial Cell Survival

Sphingosine Kinase-1 Associates with Integrin α Vβ 3 to Mediate Endothelial Cell Survival

Impact of Omega-3 and Trans Fatty Acids on Vascular Remodeling:Opposing Roles in Cardiovascular Health

Omega-3 polyunsaturated fatty acids (n-3 PUFAs) have well-recognized cardio-beneficial effects that include reductions in atherosclerotic lesions and mortality from myocardial infarction, stroke, and sudden cardiac death. In contrast, evidence suggests that more than 30,000 premature coronary deaths per year in the US alone are associated with consumption of high levels of trans isomers of unsaturated fatty acids, or trans fatty acids (TFAs). Epidemiological evidence from four large cohort studies overwhelmingly supports the conclusion that TFAs are linked to coronary heart disease (CHD). CHD in patients is associated with pathological vascular remodeling (PVR) and impaired compensatory vascular remodeling (CVR). PVR is characterized by thickening of vessel walls, reduction in elasticity, and occlusion of vessels, resulting in restricted blood flow. CVR represents a physiological process whereby vessels from a pre-existing arteriolar network develop into collateral arteries, effectively bypassing the site of arterial occlusion. The structure and function of vascular endothelial cell membranes are altered by both PVR and CVR. Oxidative stress and the induction of endothelial adhesion molecules promote PVR and inhibit CVR. It is known that n-3 PUFAs inhibit the release of soluble adhesion molecules and proinflammatory cytokines whereas TFA consumption has been linked to an increased release of these proinflammatory mediators. However, it is not known whether the changes in cell membrane composition induced by n-3 PUFAs or TFAs impact development of PVR and CVR directly or whether the changes result indirectly from altered expression and/or release of proinflammatory mediators. This review summarizes studies suggesting that n-3 PUFAs and TFAs have opposing effects on endothelial cells and that their effects on the endothelium might play an important role in vascular remodeling.

Resveratrol blunts tumor necrosis factor-α-induced monocyte adhesion and transmigration

The leukocyte recruitment and transmigration across the endothelial barrier into the vessel wall are crucial steps in atherosclerosis. Leukocyte trafficking on the endothelium is elicited by induction of endothelial adhesion molecules, and its transmigration is mediated by degradation of basement membrane proteins through enzymatic activity of matrix metalloproteinases (MMP). The current study investigated whether resveratrol, a polyphenol present in grapes and red wine, was capable of inhibiting leukocyte adhesion to tumor necrosis factor (TNF)-α-activated endothelium. It was found that resveratrol inhibited the TNF-α-activated endothelial expression of vascular cell adhesion molecule-1 in a dose-dependent manner. In addition, resveratrol hampered THP-1 monocyte adhesion to activated endothelial cells. This study further examined whether resveratrol interfered with transendothelial migration of leukocytes. The MMP-2 gelatinolytic activity of endothelial cells was enhanced by TNF-α, which was attenuated by an addition of ≥25 µM resveratrol. In addition, 25 µM resveratrol mitigated the MMP-9 activity of THP-1 cells, followed by a marked inhibition of transendothelial migration. These results demonstrated that resveratrol suppressed monocyte adhesion and migration induced by TNF-α through modulating expression of adhesion molecules and gelatinolytic activity of MMP. These findings suggest that dietary resveratrol may be therapeutic agent for inhibiting leukocyte recruitment into the subendothelium during inflammatory atherosclerosis.

What happens inside an atherosclerotic plaque?

Atherogenesis probably begins with endothelial dysfunction, whose triggers include dyslipidemia, smoking, hypertension, and insulin resistance. Endothelial dysfunction may encompass impaired barrier function; induction of endothelial adhesion molecules including VCAM-1; and migration of leukocytes and monocytes into the subendothelial space in response to chemoattractant cytokines such as monocyte chemoattractant protein-1 (MCP-1). Subsequent steps include formation of foam cells, smooth muscle cell migration, T cell activation, and, at sites of plaque disruption, platelet activation and aggregation. The smooth muscle cells form a fibrous cap. Stable plaques have a thick fibrous cap, a small lipid core, and few inflammatory cells. In contrast, lesions with higher risk of rupture have high lipid content, numerous inflammatory cells, and a thin fibrous cap with reduced collagen and vascular smooth muscle cells. Diseased coronary arteries contain multiple such vulnerable plaques, hence the need for systematic therapy to prevent acute coronary events.

Of Mice and Dogs

Large animal models have provided much of the descriptive data regarding the cellular and molecular events in myocardial infarction and repair. The availability of genetically altered mice may provide a valuable tool for specific cellular and molecular dissection of these processes. In this report we compare closed chest models of canine and mouse infarction/reperfusion qualitatively and quantitatively for temporal, cellular, and spatial differences. Much like the canine model, reperfused mouse hearts are associated with marked induction of endothelial adhesion molecules, cytokines, and chemokines. Reperfused mouse infarcts show accelerated replacement of cardiomyocytes by granulation tissue leading to a thin mature scar at 14 days, when the canine infarction is still cellular and evolving. Infarcted mouse hearts demonstrate a robust but transient postreperfusion inflammatory reaction, associated with a rapid up-regulation of interleukin-10 and transforming growth factor-beta. Unlike canine infarcts, infarcted mouse hearts show only transient macrophage infiltration and no significant mast cell accumulation. In correlation, the growth factor for macrophages, M-CSF, shows modest and transient up-regulation in the early days of reperfusion; and the obligate growth factor for mast cells, stem cell factor, SCF, is not induced. In summary, the postinfarction inflammatory response and resultant repair in the mouse heart shares many common characteristics with large mammalian species, but has distinct temporal and qualitative features. These important species-specific differences should be considered when interpreting findings derived from studies using genetically altered mice.

Histamine Antagonizes Tumor Necrosis Factor (TNF) Signaling by Stimulating TNF Receptor Shedding from the Cell Surface and Golgi Storage Pool

Tumor necrosis factor (TNF) activates pro-inflammatory functions of vascular endothelial cells (EC) through binding to receptor type 1 (TNFR1) molecules expressed on the cell surface. The majority of TNFR1 molecules are localized to the Golgi apparatus. Soluble forms of TNFR1 (as well as of TNFR2) can be shed from the EC surface and inhibit TNF actions. The relationships among cell surface, Golgi-associated, and shed forms of TNFR1 are unclear. Here we report that histamine causes transient loss of surface TNFR1, TNFR1 shedding, and mobilization of TNFR1 molecules from the Golgi in cultured human EC. The Golgi pool of TNFR1 serves both to replenish cell surface receptors and as a source of shed receptor. Histamine-induced shedding is blocked by TNF-alpha protease inhibitor, an inhibitor of TNF-alpha-converting enzyme, and through the H1 receptor via a MEK-1/p42 and p44 mitogen-activated protein kinase pathway. Cultured EC with histamine-induced surface receptor loss become transiently refractory to TNF. Histamine injection into human skin engrafted on immunodeficient mice similarly caused shedding of TNFR1 and diminished TNF-mediated induction of endothelial adhesion molecules. These results both clarify relationships among TNFR1 populations and reveal a novel anti-inflammatory activity of histamine.

Endotoxin-induced lung inflammation is independent of the complement membrane attack complex.

Several products of the activated complement system are known to modulate endothelial cell function in vitro. It has been shown that the membrane attack complex (MAC) (C5b-C9) can enhance tumor necrosis factor alpha (TNF-alpha)-induced expression of P- and E-selectin and intercellular adhesion molecule type 1 in cell cultures of human umbilical vein endothelial cells. In the present study the potential role of this synegism for lung injury during endotoxin-mediated septic shock in vivo was examined using a model of C6-deficient PVG (C-) (RT1(C)) rats and the congenic PVG (C+) (RT1(C)) strain. Following administration of a high (5 mg/kg) or low (0.5 mg/kg) dose of lipopolysaccharide (LPS) (Escherichia coli O55:B5), we determined the expression of cytokines, chemokines, and adhesion molecules as well as the recruitment of leukocytes in the lung. Challenge with intraperitoneal i.p. injections of LPS resulted in a strong induction of TNF-alpha, interleukin-1alpha/beta, cytokine-induced neutrophil chemoattractant, interferon-inducible protein 10, macrophage inflammatory proteins 1alpha and 2, macrophage chemotactic protein 1, and P-selectin. However, there were no significant differences between PVG (C-) and PVG (C+) rats. Immunoperoxidase staining showed a similar increase of lung infiltration by CD11b/c(+) leukocytes in both rat strains. We therefore conclude that the described synergism between TNF-alpha and the MAC of the complement system on the induction of endothelial adhesion molecules is dispensable for inflammatory processes during endotoxin-mediated septic shock in vivo.

The effects of monocytes on the transendothelial migration of T lymphocytes.

In vivo cell-mediated immune reactions are characterized by mixtures of monocytes and T cells. The purpose of this study was to investigate the role of monocytes on T-cell migration and induction of endothelial adhesion molecules. The in vitro model consisted of adding peripheral blood mononuclear cells (PBMC), T cells or mixtures of monocytes and T cells, to endothelial cells on a porous membrane and using flow cytometry to distinguish between the monocyte and lymphocyte components. PBMC and PBMC supernatants were highly potent at upregulating intercellular adhesion molecule-1 (ICAM-1) and inducing expression of vascular cell adhesion molecule-1 (VCAM-1) and E-selectin. Induction by supernatants was inhibited by antibodies to tumour necrosis factor-alpha (TNF-alpha) and interleukin-1 (IL)-1 beta. Using monocyte-enriched populations, as few as one monocyte to 100 endothelial cells was sufficient to upregulate adhesion molecules. Fixed monocytes also induced adhesion molecules and expressed surface-bound cytokines. In contrast, highly purified unstimulated T cells were not found to induce adhesion molecules at 4, 6, 24 or 48 hr of coculture. Purified T cells showed low-level migration through resting (VCAM-1 negative) endothelium, which was approximately doubled by addition of small numbers of monocytes or TNF-alpha. In conclusion, monocytes, via cell surface or released cytokines play an essential role in allowing large-scale recruitment of T cells to inflammatory sites in vivo.

Novel cytokine-independent induction of endothelial adhesion molecules regulated by platelet/endothelial cell adhesion molecule (CD31).

Tumor necrosis factor-alpha, interleukin-1, and endotoxin stimulate the expression of vascular endothelial cell (EC) adhesion molecules. Here we describe a novel pathway of adhesion molecule induction that is independent of exogenous factors, but which is dependent on integrin signaling and cell-cell interactions. Cells plated onto gelatin, fibronectin, collagen or fibrinogen, or anti-integrin antibodies, expressed increased amounts of E-selectin, vascular cell adhesion molecule-1, and intercellular adhesion molecule-1. In contrast, ECs failed to express E-selectin when plated on poly-L-lysine or when plated on fibrinogen in the presence of attachment-inhibiting, cyclic Arg-Gly-Asp peptides. The duration and magnitude of adhesion molecule expression was dependent on EC density. Induction of E-selectin on ECs plated at confluent density was transient and returned to basal levels by 15 h after plating when only 7 +/- 2% (n = 5) of cells were positive. In contrast, cells plated at low density displayed a 17-fold greater expression of E-selectin than did high density ECs with 57 +/- 4% (n = 5) positive for E-selectin expression 15 h after plating, and significant expression still evident 72 h after plating. The confluency-dependent inhibition of expression of E-selectin was at least partly mediated through the cell junctional protein, platelet/endothelial cell adhesion molecule-1 (PECAM-1). Antibodies against PECAM-1, but not against VE-cadherin, increased E-selectin expression on confluent ECs. Co- culture of subconfluent ECs with PECAM-1- coated beads or with L cells transfected with full-length PECAM-1 or with a cytoplasmic truncation PECAM-1 mutant, inhibited E-selectin expression. In contrast, untransfected L cells or L cells transfected with an adhesion-defective domain 2 deletion PECAM-1 mutant failed to regulate E-selectin expression. In an in vitro model of wounding the wound front displayed an increase in the number of E-selectin-expressing cells, and also an increase in the intensity of expression of E-selectin positive cells compared to the nonwounded monolayer. Thus we propose that the EC junction, and in particular, the junctional molecule PECAM-1, is a powerful regulator of endothelial adhesiveness.

Involvement of tyrosine phosphorylation in endothelial adhesion molecule induction.

Induction of endothelial adhesion molecules by the cytokine tumor necrosis factor-alpha (TNF) can occur independently of protein kinase C and activation of a protein tyrosine kinase (PTK) has recently been implicated in the upregulation of vascular cell adhesion molecule 1 (VCAM-1) by interleukin-4 (IL-4) on endothelial cells. We demonstrate that the PTK inhibitors herbimycin A or genistein suppress induction of endothelial VCAM-1 and E-selectin, as well as subsequent monocytic cell adhesion to endothelial cells stimulated by TNF. Inhibition studies indicate that specific tyrosine phosphorylation following PTK activation is involved in the mobilization of the transcription factor, nuclear factor kappa B, and VCAM-1 mRNA expression. This may have implications for pathophysiological conditions that involve the upregulation of these molecules (e.g. inflammation and atherosclerosis).