Activation Of Vascular Endothelial Cells Research Articles

The Evolving Role of Nucleotide-binding Oligomerisation Domain-like Receptor Pyrin Domain 3 Inflammasome Activation in Vascular Endothelial Cells: A Review.

In the vascular wall, defence against pathogenic damage requires a group of monocytes, the endothelium, dendritic cells, macrophages and a subsequent involvement of pattern recognition receptors anticipating damage-associated molecular patterns (DAMPs) to initiate an innate immune response. The endothelium plays a crucial role in regulating the duration, location and extent of the inflammatory cascade to ensure a definitive immune defence. Molecular changes in the expression of chemokines and cell adhesion molecules ensure protective responses against infection and injury. The multiprotein oligomer complex nucleotide-binding oligomerisation domain (NOD)-like receptor pyrin domain 3 (NLRP3) inflammasome plays a key role in the activation of inflammatory processes in response to DAMPs and pattern-associated molecular patterns. As a result of NLRP3 inflammasome activation, caspase-1 is activated and interleukin-1β (IL-1β) is produced. Caspase-1 is the main mediator of inflammatory feedback to tissue injury, and it is engaged both in the initiation of the inflammatory response and in the induction of cell death. NLRP3 inflammasome promotes further inflammatory responses and pyroptosis in the vascular endothelium; thus, its optimum regulation is crucial in cardiovascular homeostasis. This review outlines our current perception of the role of NLRP3 in vascular endothelial cells.

Galangin reduces vascular endothelial cell dysfunction via Heme oxygenase-1 signaling.

As one of the independent risk factors for atherosclerosis (AS), oxidized low-density lipoprotein (ox-LDL) can trigger damage to the vascular intima and induce the expression of various adhesion molecules. This study aimed to explore the effects of galangin, an extract of galangal, on ox-LDL-induced vascular endothelial cells. The effects of different concentrations of galangin or ox-LDL on the metabolic activity of vascular endothelial cells were determined using the CCK8 assay. Afterward, the role of galangin in the expression levels of inflammatory factors was assessed using RT-qPCR and Western blotting. In addition, the influences of galangin on apoptosis and endothelial-mesenchymal transition (EndMT) were also evaluated. Through molecular docking, the Heme oxygenase-1 (HO-1) signaling pathway was proposed, and then the effects of the HO-1 signaling pathway on the regulatory roles of galangin were evaluated. In this study, galangin was found to effectively increase the metabolic activity of ox-LDL-induced cells in a concentration-dependent manner. In addition, galangin was found to reduce ox-LDL-induced cell inflammation, apoptosis, and EndMT. Moreover, galangin could combine with HO-1 and regulate the HO-1 signaling pathway. The effects of galangin on cells were shown to be through the HO-1 signaling pathway. To sum up, galangin reduced ox-LDL-induced inflammation, apoptosis, and EndMT of vascular endothelial cells via regulating the HO-1 signaling pathway.

A human pluripotent stem cell-based model of SARS-CoV-2 infection reveals an ACE2-independent inflammatory activation of vascular endothelial cells through TLR4.

SummaryTo date, the direct causative mechanism of SARS-CoV-2-induced endotheliitis remains unclear. Here, we report that human ECs barely express surface ACE2, and ECs express less intracellular ACE2 than non-ECs of the lungs. We ectopically expressed ACE2 in hESC-ECs to model SARS-CoV-2 infection. ACE2-deficient ECs are resistant to the infection but are more activated than ACE2-expressing ones. The virus directly induces endothelial activation by increasing monocyte adhesion, NO production, and enhanced phosphorylation of p38 mitogen-associated protein kinase (MAPK), NF-κB, and eNOS in ACE2-expressing and -deficient ECs. ACE2-deficient ECs respond to SARS-CoV-2 through TLR4 as treatment with its antagonist inhibits p38 MAPK/NF-κB/ interleukin-1β (IL-1β) activation after viral exposure. Genome-wide, single-cell RNA-seq analyses further confirm activation of the TLR4/MAPK14/RELA/IL-1β axis in circulating ECs of mild and severe COVID-19 patients. Circulating ECs could serve as biomarkers for indicating patients with endotheliitis. Together, our findings support a direct role for SARS-CoV-2 in mediating endothelial inflammation in an ACE2-dependent or -independent manner.

Upregulation of Neogenin-1 by a CREB1-BAF47 Complex in Vascular Endothelial Cells is Implicated in Atherogenesis.

Atherosclerosis is generally considered a human pathology of chronic inflammation, to which endothelial dysfunction plays an important role. Here we investigated the role of neogenin 1 (Neo-1) in oxidized low-density lipoprotein (oxLDL) induced endothelial dysfunction focusing on its transcriptional regulation. We report that Neo-1 expression was upregulated by oxLDL in both immortalized vascular endothelial cells and primary aortic endothelial cells. Neo-1 knockdown attenuated whereas Neo-1 over-expression enhanced oxLDL-induced leukocyte adhesion to endothelial cells. Neo-1 regulated endothelial-leukocyte interaction by modulating nuclear factor kappa B (NF-κB) activity to alter the expression of adhesion molecules. Neo-1 blockade with a blocking antibody ameliorated atherogenesis in Apoe −/− mice fed a Western diet. Ingenuity pathway analysis combined with validation assays confirmed that cAMP response element binding protein 1 (CREB1) and Brg1-associated factor 47 (BAF47) mediated oxLDL induced Neo-1 upregulation. CREB1 interacted with BAF47 and recruited BAF47 to the proximal Neo-1 promoter leading to Neo-1 trans-activation. In conclusion, our data delineate a novel transcriptional mechanism underlying Neo-1 activation in vascular endothelial cells that might contribute to endothelial dysfunction and atherosclerosis.

Mechanism of Carthami Flos and Lepidii Semen drug pair in inhibition of myocardial fibrosis by improving cardiac microenvironment based on network pharmacology and animal experiment

Previously, Carthami Flos and Lepidii Semen(CF-LS) drug pair has been proved effective in inhibiting myocardial fibrosis(MF) by blunting the activity of cardiac fibroblasts. The present study explored the underlying mechanism of CF-LS in inhibiting MF by improving the cardiac microenvironment based on network pharmacology combined with experimental verification. Active compounds and potential targets of CF-LS were retrieved from Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform(TCMSP), and the potential targets of MF were obtained from GeneCards, Online Mendelian Inheritance in Man(OMIM), and Pharmacogenetics and Pharmacogenomics Knowledge Base(PharmGKB). The "active component-target-MF" network was constructed and analyzed by Cytoscape 3.8.1. The protein-protein interaction(PPI) network was constructed by STRING. The Gene Ontology(GO) biological process enrichment analysis was performed by CluoGO plug-in. Kyoto Encyclopedia of Genes and Genomes(KEGG) signaling pathway enrichment analysis was performed by R 4.0.2 and Funrich. Subsequently, the inhibitory effect of CF-LS on MF was investigated based on angiotensin Ⅱ(Ang Ⅱ)-induced MF rats. RT-PCR and ELISA were used to verify the effect of CF-LS on the targets of signaling pathways related to vascular endothelial cells predicted by the network pharmacology. Thirty-one active components and 204 potential targets of CF-LS, 4 671 MF-related targets, and 174 common targets were obtained. The network analysis showed that the key targets of CF-LS against MF included RAC-alpha serine/threonine-protein kinase(AKT1), transcription factor AP-1(JUN), mitogen-activated protein kinase 1(MAPK1), cellular tumor antigen p53(TP53), transcription factor p65(RELA), and mitogen-activated protein kinase 8(MAPK8). Biological processes mainly involved regulation of blood vessel diameter, regulation of blood vessel endothelial cell migration, cell death in response to oxidative stress, etc. Advanced glycation end products(AGE)-receptor for advanced glycation end products(RAGE) signaling pathway, phosphoinositide 3-kinase(PI3 K)-serine/threonine protein kinase(AKT) signaling pathway, hypoxia-inducible factor-1(HIF-1) signaling pathway, integrin signaling pathway, transforming growth factor-β(TGF-β) signaling pathway, etc. were involved in signaling pathway enrichment. Literature retrieval confirmed that some of these signaling pathways were closely related to vascular endothelial cells, including AGE-RAGE, PI3 K-AKT, HIF-1α, p53, the transcription factor activator protein-1(AP-1), integrin, p38 MAPK, and TGF-β. Animal experiments showed that CF-LS inhibited MF induced by Ang Ⅱ in rats by suppressing the expression of RAGE, HIF-1α, integrin β6, and TGF-β1. The inhibitory effect of CF-LS on MF has the characteristics of multiple components, multiple targets, and multiple pathways. CF-LS can inhibit MF by regulating the activity of vascular endothelial cells in the cardiac microenvironment.

The role of Cold-Inducible RNA-binding protein in respiratory diseases.

Cold‐inducible RNA‐binding protein (CIRP) is a stress‐response protein that is expressed in various types of cells and acts as an RNA chaperone, modifying the stability of its targeted mRNA. Intracellular CIRP could also be released into extracellular space and once released, extracellular CIRP (eCIRP) acts as a damage‐associated molecular pattern (DAMP) to induce and amplify inflammation. Recent studies have found that eCIRP could promote acute lung injury (ALI) via activation of macrophages, neutrophils, pneumocytes and lung vascular endothelial cells in context of sepsis, haemorrhagic shock, intestinal ischemia/reperfusion injury and severe acute pancreatitis. In addition, CIRP is also highly expressed in the bronchial epithelial cells and its expression is upregulated in the bronchial epithelial cells of patients with chronic obstructive pulmonary diseases (COPD) and rat models with chronic bronchitis. CIRP is a key contributing factor in the cold‐induced exacerbation of COPD by promoting the expression of inflammatory genes and hypersecretion of airway mucus in the bronchial epithelial cells. Besides, CIRP is also involved in regulating pulmonary fibrosis, as eCIRP could directly activate and induce an inflammatory phenotype in pulmonary fibroblast. This review summarizes the findings of CIRP investigation in respiratory diseases and the underlying molecular mechanisms.

Functional rare variant in a C/EBPbeta binding site in NINJ2 gene increases the risk of coronary artery disease.

Objective: NINJ2 regulates activation of vascular endothelial cells, and genome-wide association studies showed that variants in NINJ2 confer risk to stroke. However, whether variants in NINJ2 are associated with coronary artery disease (CAD) is unknown.Methods: We genotyped rs34166160 in NINJ2 in two independent Chinese GeneID populations which included 2,794 CAD cases and 4,131 controls, and performed genetics association studies. Functional studies were also performed to reveal the mechanisms.Results: Allele rs34166160 significantly confers risk to CAD in the GeneID Hubei population which contained 1,440 CAD cases and 2,660 CAD-free controls (observed P-obs = 6.39 × 10−3 with an odds ratio (OR) was 3.39, adjusted P-adj = 8.12 × 10−3 with an OR of 3.10). The association was replicated in another population, GeneID Shandong population contained 1,354 CAD cases and 1,471 controls (P-obs = 3.33 × 10−3 with an OR of 3.14, P-adj = 0.01 with an OR of 2.74). After combining the two populations, the association was more significant (P-obs = 1.57 × 10−5 with an OR of 3.58, P-adj = 3.41 × 10−4 with an OR of 2.80). In addition, we found that rs34166160 was associated with the mRNA expression level of NINJ2 and the flanking region of rs34166160 can directly bind with transcriptional factor CCAAT-box/enhancer-binding protein beta, and the risk A allele has more transcription activity than non-risk C allele with or without LPS in HUVEC cells.Conclusions: Our study demonstrates that the functional rare variant rs34166160 in NINJ2 confers risk to CAD for the first time, and these findings further expand the range of the pathology of CAD and atherosclerosis.

RETRACTED: Excellent application value of a rare pentanuclear [Ca5(COO)8] cluster-based compound in atherosclerosis treatment and nursing

Presented here is a novel Ca(II) compound, that is, {[(CH 3 ) 2 NH 2 ] 2 [Ca 5 (L) 4 (DMF) 4 ]} n ( 1 , H 3 L ​= ​4,4′,4″-ticarboxytriphenylamine), with rare pentanuclear [Ca 5 (COO) 8 ] clusters as building subunits. The L 3− ligands connected all pentanuclear [Ca 5 (COO) 8 ] clusters into a 3-dimensional anionic skeleton that was balanced via dimethylamine cations. Furthermore, the thermal behavior and compound's luminescent performance were also examined. For the treatment of atherosclerosis, the enzyme linked immunosorbent assay (ELISA) detection assay was implemented for the exploration of the fresh compound's influence against the inflammatory cytokines levels released into plasma. After that, the real time reverse transcription-polymerase chain reaction (RT-PCR) was finished and the nuclear factor kappa-B (NF-κb) signaling pathway activation in vascular endothelial cells was tested. • A novel Ca(II) compound was prepared. • The thermal and luminescent properties were examined. • Its treatment activity of atherosclerosis was studied.

Abstract 12466: Suppression of Inflammatory Activity in Vascular Endothelial Cells Reduces EndMT in Response to Oscillatory Shear Stress

Background: The incidence of pro-atherogenic lesions is greater in the branching regions of artery compared to non-branching regions. Disturbed blood flow in the atheroprone regions exerts oscillatory shear stress (OSS) to the vascular wall, particularly endothelial cells (ECs), and OSS is a risk factor for the development of pro-atherogenic lesions. This study aims to assess the impact of OSS on phenotypic transition in artery ECs. Methods and Results: Immunofluorescence staining and image quantification revealed that inflammatory activity and endothelial-to-mesenchymal transition (EndMT) are greater in mouse aortic arch than in the descending thoracic aorta. Inflammatory biomarker ICAM-1 is colocalized with the EndMT biomarker, vimentin and α-smooth muscle actin, in ECs of the aorta arch. As cells in aortic arch sustain OSS, we tested the hypothesis that OSS induces EndMT in artery ECs by a pro-inflammatory mechanism, using a three-dimensional microengineered human artery-on-a-chip system. Human coronary artery ECs were cultured on the surface of a collagen I-coated membrane and subjected to OSS. Single-cell RNA sequencing analysis revealed that inflammatory and EndMT-related genes were enriched in ECs after being exposed to OSS for 24 h. OSS-induced inflammatory response and EndMT were confirmed by immunoblotting and immunofluorescence staining. These changes were abolished by inhibiting the p38 MAPK-NF-κB signaling pathway. Moreover, anti-inflammatory cytokine, IL-37, suppressed the inflammatory response and prevented EndMT in ECs exposed to OSS. Importantly, expression of IL-37 in mice markedly reduced the level of inflammatory biomarker and the density of cells displaying EndMT biomarkers in the endothelium of aortic arch. Conclusion: OSS induces EndMT in artery ECs through a pro-inflammatory mechanism involving the p38 MAPK-NF-κB signaling pathway and contributes to the pro-atherogenic microenvironment in regions sustaining disturbed blood flow. Anti-inflammatory cytokine IL-37 may have the therapeutic potential for suppressing endothelial phenotypic transition caused by disturbed blood flow.

Insight Into the Roles of Non-coding RNA in Bronchopulmonary Dysplasia.

Bronchopulmonary dysplasia (BPD) is a chronic lung disease most commonly occurring in premature infants, and its pathological manifestations are alveolar hypoplasia and dysregulation of pulmonary vasculature development. The effective treatment for BPD has not yet been established. Non-coding RNAs, including microRNAs and long non-coding RNAs do not encode proteins, but can perform its biological functions at the RNA level. Non-coding RNAs play an important role in the incidence and development of BPD by regulating the expression of genes related to proliferation, apoptosis, angiogenesis, inflammation and other cell activities of alveolar epithelial cells and vascular endothelial cells. Here we summarize the role of non-coding RNAs in BPD, which provides possible molecular marker and therapeutic target for the diagnosis and treatment of BPD.

Synthesis of Reactive Sulfur Species in Cultured Vascular Endothelial Cells after Exposure to TGF-β1: Induction of Cystathionine γ-Lyase and Cystathionine β-Synthase Expression Mediated by the ALK5-Smad2/3/4 and ALK5-Smad2/3-ATF4 Pathways.

Transforming growth factor-β1 (TGF-β1) occurs at high levels at damage sites of vascular endothelial cell layers and regulates the functions of vascular endothelial cells. Reactive sulfur species (RSS), such as cysteine persulfide, glutathione persulfide, and hydrogen persulfide, are cytoprotective factors against electrophiles such as reactive oxygen species and heavy metals. Previously, we reported that sodium trisulfide, a sulfane sulfur donor, promotes vascular endothelial cell proliferation. The objective of the present study was to clarify the regulation and significance of RSS synthesis in vascular endothelial cells after exposure to TGF-β1. Bovine aortic endothelial cells in a culture system were treated with TGF-β1 to assess the expression of intracellular RSS, the effect of RSS on cell proliferation in the presence of TGF-β1, induction of RSS-producing enzymes by TGF-β1, and intracellular signal pathways that mediate this induction. The results suggest that TGF-β1 increased intracellular RSS levels to modulate its inhibitory effect on proliferation. The increased production of RSS, probably high-molecular-mass RSS, was due to the induction of cystathionine γ-lyase and cystathionine β-synthase, which are RSS-producing enzymes, and the induction was mediated by the ALK5-Smad2/3/4 and ALK5-Smad2/3-ATF4 pathways in vascular endothelial cells. TGF-β1 regulates vascular endothelial cell functions such as proliferation and fibrinolytic activity; intracellular high-molecular-mass RSS, which are increased by TGF-β1, may modulate the regulation activity in vascular endothelial cells.

Hyperuricemia enhances procoagulant activity of vascular endothelial cells through TMEM16F regulated phosphatidylserine exposure and microparticle release

The link between serum uric acid (SUA) and the risk of venous thromboembolism (VTE) is well established. Recent data suggested a causative role of UA in endothelial cells (ECs) dysfunction. However, the molecular mechanism of high UA on thrombogenesis is unknown. We investigate whether high UA induce phosphatidylserine (PS) externalization and microparticle (MP) shedding in cultured EC, and contribute to UA-induced hypercoagulable state. In the present study, we demonstrate that UA induces PS exposure and EMP release of EC in a concentration- and time-dependent manner, which enhances the procoagulant activity (PCA) of EC and inhibited over 90% by lactadherin in vitro. Furthermore, hyperuricemic rat model was used to evaluate the development of thrombi following by flow stasis in the inferior vena cava (IVC). Hyperuricemia group is more likely to form large and hard thrombi compared with control. Importantly, we found that TMEM16F expression is significantly upregulated in UA-treated EC, which is crucial for UA-induced PS exposure and MP formation. Additionally, UA increases the generation of reactive oxygen species (ROS), lipid peroxidation, and cytosolic Ca2+ concentration in EC, which might contribute to increased TMEM16F expression. Using confocal microscopy, we also observed disruption of the actin cytoskeleton, suggesting that depolymerization of actin filaments might be required for TMEM16F activation and followed by PS exposure and membrane blebbing in UA-treated EC. Our results demonstrate a thrombotic role of EC in hyperuricemia through TMEM16F-mediated PS exposure and MPs release.

Eicosapentaenoic acid reduces cytokine-induced expression of multiple proteins related to platelet activation and aggregation in pulmonary and vascular endothelium

Background and Aims: Platelet aggregation and thrombus formation link to cardiovascular (CV) disease and its clinical manifestations. Eicosapentaenoic acid (EPA), an omega-3 fatty acid (O3FA), reduced CV events, including ischemic stroke, in high-risk patients (REDUCE-IT). We compared the effects of EPA on expression of proteins involved in platelet activation and aggregation in both pulmonary and vascular endothelial cells (ECs) under conditions of inflammation with cytokine challenge.

Comparison of cytotoxicity of cigarette smoke extract derived from heat-not-burn and combustion cigarettes in human vascular endothelial cells

The present study compared the properties of mainstream smoke generated from heat-not-burn (HNB) cigarettes and a combustion cigarette (hi-lite™ brand). Three types of cigarette heating devices were used to generate cigarette smoke at different heating temperatures [Ploom S™ (200 °C), glo™ (240 °C), and IQOS™ (300–350 °C)]. Mainstream smoke was generated using the following puffing regimen: volume, 55 mL; duration, 3 s; and interval, 30 s. The rank order of particulate phase (nicotine and tar) amounts trapped on a Cambridge filter was Ploom S < glo < IQOS < hi-lite. Heated cigarette-derived smoke extract (hCSE) from the devices except for Ploom S, and burned CSE (bCSE) decreased mitochondrial metabolic activity (glo < IQOS < hi-lite) in human vascular endothelial cells. Furthermore, the cytotoxicity was reduced by removing the particulate phase from the mainstream smoke. Endothelial nitric oxide synthase activity was reduced by nicotine- and tar-free CSE of IQOS and hi-lite (IQOS < hi-lite), but not Ploom S and glo. These inhibitory effects were diminished by removing the carbonyl compounds from the mainstream smoke. These results indicated that the cytotoxicity of hCSE was lower than that of bCSE in vascular endothelial cells.

Cdc42 has important roles in postnatal angiogenesis and vasculature formation

Cdc42, a Rho family low molecular weight G protein, has important roles in various cell functions, including cytoskeletal rearrangement, cell adhesion and cell proliferation and differentiation. To investigate the involvement of Cdc42 in the activities of vascular endothelial cells, we generated Cdc42 conditional knockout mice in which Cdc42 was time -specifically deficient in vascular endothelial cells (Cdc42 ​fl/fl; VE-Cad CreERT: Cdc42 cKO). When the Cdc42 gene was deleted after birth, Cdc42 cKO mice were smaller than the control mice, and died between postnatal day 8 (P8) and P10. Necropsy findings confirmed that these mice had various pathological aberrances in the vessels of most organs, such as blood flow congestion and blood cell invasion. Electron microscopic observations also revealed that capillary endothelial cells were detached from the basement membrane as well as phagocytosis of dead endothelial cells induced by macrophages. Moreover, vascular sprouting from aortic rings induced by VEGF-A was diminished in samples from the Cdc42 cKO mice because of an endothelial cell proliferation defect. These results suggest that Cdc42 in vascular endothelial cells has important roles in blood vessel formation after birth.

Canine Angiostrongylus vasorum-Induced Early Innate Immune Reactions Based on NETs Formation and Canine Vascular Endothelial Cell Activation In Vitro.

Simple SummaryAngiostrongylus vasorum is a cardiopulmonary nematode that affects canids, residing in the pulmonary artery and right atrium/ventricle. Due to its location, the parasite will have a close interaction with the different components of the innate immune system, including endothelial cells and polymorphonuclear neutrophils (PMN). Here we evaluated the expression of adhesion molecules of canine aortic endothelial cells (CAEC), and NETs formation by co-culture of freshly isolated canine PMN with A. vasorum L3. Overall, we found distinct inter-donor variations in adhesion molecule expression among CAEC isolates. Additionally, PMN and A. vasorum co-culture induced NETs release without affecting larval viability.Due to its localization in the canine blood stream, Angiostrongylus vasorum is exposed to circulating polymorphonuclear neutrophils (PMN) and the endothelial cells of vessels. NETs release of canine PMN exposed to A. vasorum infective stages (third stage larvae, L3) and early pro-inflammatory immune reactions of primary canine aortic endothelial cells (CAEC) stimulated with A. vasorum L3-derived soluble antigens (AvAg) were analyzed. Expression profiles of the pro-inflammatory adhesion molecules ICAM-1, VCAM-1, P-selectin and E-selectin were analyzed in AvAg-stimulated CAEC. Immunofluorescence analyses demonstrated that motile A. vasorum L3 triggered different NETs phenotypes, with spread NETs (sprNETs) as the most abundant. Scanning electron microscopy confirmed that the co-culture of canine PMN with A. vasorum L3 resulted in significant larval entanglement. Distinct inter-donor variations of P-selectin, E-selectin, ICAM-1 and VCAM-1 gene transcription and protein expression were observed in CAEC isolates which might contribute to the high individual variability of pathological findings in severe canine angiostrongylosis. Even though canine NETs did not result in larval killing, the entanglement of L3 might facilitate further leukocyte attraction to their surface. Since NETs have already been documented as involved in both thrombosis and endothelium damage events, we speculate that A. vasorum-triggered NETs might play a critical role in disease outcome in vivo.

Nur77 Attenuates Inflammasome Activation by Inhibiting Caspase-1 Expression in Pulmonary Vascular Endothelial Cells

Inflammasomes are intracellular multiprotein complexes that help trigger and maintain the inflammatory response as part of the innate immune system. Recently, it has been increasingly recognized that aberrant inflammasome activation is critically involved in endothelial dysfunction in a variety of human diseases, such as atherosclerosis, acute lung injury (ALI), and type 2 diabetes. The molecular mechanisms underlying endothelial inflammasome activation, however, have not been completely elucidated. In the present study, we identified orphan nuclear receptor Nur77 as a novel regulator in controlling inflammasome activation in vascular endothelial cells (ECs). We demonstrated that LPS-induced inflammasome activation was significantly inhibited by ectopic overexpression of Nur77, predominantly through transcriptional suppression of caspase-1 expression in vascular ECs. Consistent with this observation, we found that LPS-induced inflammasome activation was significantly augmented in lung ECs isolated from Nur77-knockout mice. Mechanistically, we showed that Nur77-induced inhibition of caspase-1 expression was due to an inhibition of IRF1 (IFN regulatory factor 1) expression and its subsequent binding to the caspase-1 promoter. Importantly, in a mouse model of LPS-induced ALI, Nur77 knockout led to a marked activation of caspase-1 in the lung, increased alveolar and circulating IL-1β levels, and exacerbated ALI, all of which were substantially inhibited by administration of caspase-1 inhibitor. Together, our results support the presence of an important role for Nur77 in controlling inflammasome activation in vascular ECs and suggest that Nur77 could be a novel therapeutic target for the treatment of human diseases associated with aberrant inflammasome activation, such as ALI and atherosclerosis.

MicroRNA-126 Attenuates the Effect of Chemokine CXCL8 on Proliferation, Migration, Apoptosis, and MAPK-Dependent Signaling Activity of Vascular Endothelial Cells Cultured in a Medium with High Glucose Concentration.

We studied the mechanisms by which microRNA-126 regulates proliferation and migration of human umbilical vein endothelial cells (HUVEC) cultured in a medium with high glucose concentration and treated with chemokine CXCL8. Cell proliferation, apoptosis, and migration were analyzed by the CCK-8 assay, Annexin V-PI staining, and Transwell assay, respectively. The ratios of p-ERK/ERK, p-P38/P38, p-JNK/JNK were determined by ELISA. HUVEC cells cultured in the presence of high glucose concentration (30 mmol/ml) and treated with CXCL8 (50 ng/ml) demonstrated more intensive proliferation, migration, and p-ERK/ERK, p-P38/P38, and p-JNK/JNK ratios and significantly lower apoptosis rate than control cells (high glucose, no treatment) and cells treated with CXCL8 and transfected with microRNA-126-mimic. Thus, microRNA-126 regulates proliferation and migration of HUVEC cells cultured in the presence of high glucose concentrations and treated with CXCL8 through inhibition of MAPK signaling pathway.

Platelets in COVID-19: “innocent by-standers” or active participants?

One of the most dangerous features of the new coronavirus infection caused by the SARS-CoV-2 virus is the tendency of the hemostasis system of patients to excessive thrombus formation. Among the possible causes of this pathology, both the activation of vascular endothelial cells, leading to the exposure of tissue factor by these cells, and direct activation of the plasma hemostasis were named. Besides, there is a significant change in platelet responses to activation, which is not accompanied by significant thrombocytopenia. The mechanism of platelet dysfunction is rather controversial. On the one hand, there are suggestions that platelets can act as a direct “container” for the virus, thus spreading it throughout the body. On the other hand, the presence of viral RNA in platelets has been demonstrated in only one study, while other authors have obtained the opposite result. Another mechanism of the virus's direct effect on platelets is the penetration of the virus into megakaryocytes and the subsequent violation of thrombocytopoiesis. However, three of the four published works show that platelets from patients with SARS-CoV-2 are in an activated state (the so-called platelet pre-activation). This phenomenon can be caused by the direct influence of the virus and the effect of thromboinflammation in the lungs on platelet functions. Here we review the known data and possible causes of the platelet functionality changes observed in patients with SARS-CoV-2.

MMP-9 Mediates Cross-Talk between Neutrophils and Endothelial Cells in Psoriasis

In their report, Chen etal. provide new insights into psoriasis pathogenesis, showing that neutrophil infiltration of skin lesions increases vascular endothelial cell (VEC) activation, leading to cutaneous vasodilation and enhanced vascular permeability. In patients with psoriasis, neutrophil-derived matrix metalloproteinase 9 (MMP-9) plays a pivotal role in VEC barrier dysfunction, via extracellular signal-regulated kinase-1/2 and p38 pathways. Pharmacologic inhibition of MMP-9 in two different models confers reduced cutaneous vasodilation, vascular permeability, and inflammation, suggesting MMP-9 as a target in psoriasis pathogenesis.