Endothelial cell-selective adhesion molecule modulates atherosclerosis through plaque angiogenesis and monocyte-endothelial interaction

Modeling Foam Cell Formation in A Hydrogel-Based 3D-Intimal Model: A Study of The Role of Multi-Diseases During Early Atherosclerosis

Monocyte recruitment and transmigration are crucial in atherosclerotic plaque development. The multi-disease complexities aggravate the situation and continue to be a constant concern for understanding atherosclerosis plaque development. Herein, a 3D hydrogel-based model that integrates disease-induced microenvironments is sought to be designed, allowing us to explore the early stages of atherosclerosis, specifically examining monocyte fate in multi-disease complexities. As a proof-of-concept study, murine cells are employed to develop the model. The model is constructed with collagen embedded with murine aortic smooth muscle cells and a murine endothelial monolayer lining. The model achieves in vitro disease complexities using external stimuli such as glucose and lipopolysaccharide (LPS). Hyperglycemia exhibits a significant increase in monocyte adhesion but no enhancement in monocyte transmigration and foam cell conversion compared to euglycemia. Chronic infection achieved by LPS stimulation results in a remarkable augment in initial monocyte attachment and a significant increment in monocyte transmigration and foam cells in all concentrations. Moreover, the model exhibits synergistic sensitivity under multi-disease conditions such as hyperglycemia and infection, enhancing initial monocyte attachment, cell transmigration, and foam cell formation. Additionally, western blot data prove the enhanced levels of inflammatory biomarkers, indicating the model's capability to mimic disease-induced complexities during early atherosclerosis progression.

Bioactive TNIIIA2 Sequence in Tenascin-C Is Responsible for Macrophage Foam Cell Transformation; Potential of FNIII14 Peptide Derived from Fibronectin in Suppression of Atherosclerotic Plaque Formation

One of the extracellular matrix proteins, tenascin-C (TN-C), is known to be upregulated in age-related inflammatory diseases such as cancer and cardiovascular diseases. Expression of this molecule is frequently detected, especially in the macrophage-rich areas of atherosclerotic lesions; however, the role of TN-C in mechanisms underlying the progression of atherosclerosis remains obscure. Previously, we found a hidden bioactive sequence termed TNIIIA2 in the TN-C molecule and reported that the exposure of this sequence would be carried out through limited digestion of TN-C by inflammatory proteases. Thus, we hypothesized that some pro-atherosclerotic phenotypes might be elicited from macrophages when they were stimulated by TNIIIA2. In this study, TNIIIA2 showed the ability to accelerate intracellular lipid accumulation in macrophages. In this experimental condition, an elevation of phagocytic activity was observed, accompanied by a decrease in the expression of transporters responsible for lipid efflux. All these observations were mediated through the induction of excessive β1-integrin activation, which is a characteristic property of the TNIIIA2 sequence. Finally, we demonstrated that the injection of a drug that targets TNIIIA2's bioactivity could rescue mice from atherosclerotic plaque expansion. From these observations, it was shown that TN-C works as a pro-atherosclerotic molecule through an internal TNIIIA2 sequence. The possible advantages of clinical strategies targeting TNIIIA2 are also indicated.

Adipocyte hypertrophy associates with in vivo postprandial fatty acid metabolism and adipose single-cell transcriptional dynamics

Adipocyte hypertrophy is associated with metabolic complications independent of obesity. We aimed to determine: 1) the association between adipocyte size and postprandial fatty acid metabolism; 2) the potential mechanisms driving the obesity-independent, hypertrophy-associated dysmetabolism in vivo and at a single-cell resolution. Tracers with positron emission tomography were used to measure fatty acid metabolism in 40 men and women with normal or impaired glucose tolerance (NCT02808182), and single nuclei RNA-sequencing (snRNA-seq) to determine transcriptional dynamics of subcutaneous adipose tissue (AT) between individuals with AT hypertrophy vs. hyperplasia matched for sex, ethnicity, glucose-tolerance status, BMI, total and percent body fat, and waist circumference. Adipocyte size was associated with high postprandial total cardiac fatty acid uptake and higher visceral AT dietary fatty acid uptake, but lower lean tissue dietary fatty acid uptake. We found major shifts in cell transcriptomal dynamics with AT hypertrophy that were consistent with in vivo metabolic changes.

The role of oxidative stress in diabetes mellitus-induced vascular endothelial dysfunction

Diabetes mellitus is a metabolic disease characterized by long-term hyperglycaemia, which leads to microangiopathy and macroangiopathy and ultimately increases the mortality of diabetic patients. Endothelial dysfunction, which has been recognized as a key factor in the pathogenesis of diabetic microangiopathy and macroangiopathy, is characterized by a reduction in NO bioavailability. Oxidative stress, which is the main pathogenic factor in diabetes, is one of the major triggers of endothelial dysfunction through the reduction in NO. In this review, we summarize the four sources of ROS in the diabetic vasculature and the underlying molecular mechanisms by which the pathogenic factors hyperglycaemia, hyperlipidaemia, adipokines and insulin resistance induce oxidative stress in endothelial cells in the context of diabetes. In addition, we discuss oxidative stress-targeted interventions, including hypoglycaemic drugs, antioxidants and lifestyle interventions, and their effects on diabetes-induced endothelial dysfunction. In summary, our review provides comprehensive insight into the roles of oxidative stress in diabetes-induced endothelial dysfunction.

Mice with endothelial cell-selective adhesion molecule deficiency develop coronary microvascular rarefaction and left ventricle diastolic dysfunction

Endothelial cell-selective adhesion molecule (ESAM) regulates inflammatory cell adhesion and transmigration and promotes angiogenesis. Here, we examined the role of ESAM in cardiac vascularization, inflammatory cell infiltration, and left ventricle (LV) diastolic function under basal and hemodynamic stress conditions. We employed mice with homozygous genetic deletion of ESAM (ESAM-/- ) and also performed uninephrectomy and aldosterone infusion (UNX-Aldo) to induce volume and pressure overload. Using echocardiography, we found that ESAM-/- mice display no change in systolic function. However, they develop LV diastolic dysfunction, as indicated by a significantly reduced E/A ratio (E = early, A = late mitral inflow peak velocities), increased E/e' ratio, isovolumic relaxation time (IVRT), and E wave deceleration time. An unbiased automated tracing and 3D reconstruction of coronary vasculature revealed that ESAM-/- mice had reduced coronary vascular density. Arteries of ESAM-/- mice exhibited impaired endothelial sprouting and in cultured endothelial cells siRNA-mediated ESAM knockdown reduced tube formation. Changes in ESAM-/- mice were accompanied by elevated myocardial inflammatory cytokine and myeloperoxidase-positive neutrophil levels. Furthermore, UNX-Aldo procedure in wild type mice induced LV diastolic dysfunction, which was accompanied by significantly increased serum ESAM levels. When compared to wild types, ESAM-/- mice with UNX-Aldo displayed worsening of LV diastolic function, as indicated by increased IVRT and pulmonary edema. Thus, we propose that ESAM plays a mechanistic role in proper myocardial vascularization and the maintenance of LV diastolic function under basal and hemodynamic stress conditions.

Functions of two distinct Kupffer cells in the liver

Tissue-resident macrophages play critically important roles in host homeostasis and pathogenesis of diseases, with the functions of phagocytosis, metabolism, and immune modulation. Recently, two research studies accomplished by a collaborated group of researchers showed that there are two populations of liver resident Kupffer cells (KCs), including a major cluster of differentiation 206 low expression (CD206low)endothelial cell-selective adhesion molecule negative (ESAM-) population (KC1) and a minor CD206highESAM+ population (KC2). Both KC1 and KC2 express KC markers, such as C-type lectin domain family 4 member F (CLEC4F) and T-cell membrane protein 4 (Tim4). In fatty liver, the frequency of KC2 was increased, and those KC2 expressed some markers like liver sinusoidal endothelial cells (LSECs), such as CD31 and ESAM. In addition, KC2 population had a relatively higher expression of CD36, as fatty acid transporter, which was implicated in the production of reactive oxygen species (ROS) and lipid peroxidation. Furthermore, this collaborated group also showed that KC2 can cross-present hepatocellular antigens to prime antiviral function of CD8+ T cells by sensing interleukin-2 (IL-2) in hepatitis B virus (HBV) replication-competent transgenic mice. Increasing evidence shows that targeting hepatic macrophages can prevent and reverse non-alcoholic fatty liver disease (NAFLD), with a new suggested name metabolic dysfunction-associated fatty liver disease (MAFLD) to include metabolic dysfunction-associated fatty liver diseases, such as viruses and alcohol. In summary, differentiating specific populations of hepatic macrophages is critically important for the treatment of MAFLD or NAFLD, and their overlaps. Markers specifically expressed on sub-types of hepatic macrophages may be applied for liver disease diagnosis.

Propofol attenuates monocyte-endothelial adhesion via modulating connexin43 expression in monocytes

AIMS

Monocyte-endothelial adhesion is considered to be the primary initiator of inflammatory vascular diseases, such as atherosclerosis. Connexin 43 (Cx43) has been reported to play an important part in this process, however, the underlying mechanisms are not fully understood. Intravenous anesthetics, propofol is commonly used in the perioperative period and in the intensive care unit, and considered to have good anti-inflammatory and antioxidant effects. Thus, we speculate that propofol could influence monocyte-endothelial adhesion, and explore whether its possible mechanism is relative with Cx43 expression in U937 monocytes influencing cell adhesion of U937 monocytes to human umbilical vein endothelial cells (HUVEC).

MAIN METHODS

Cx43-siRNAs or pc-DNA-Cx43 were used to alter Cx43 expression in U937 monocytes. Propofol was given as pretreatments to U937 monocytes. Then, cell adhesion, ZO-1, LFA-1, VLA-4, COX and MCP-1 were determined. PI3K/AKT/NF-κB signaling pathway was explored to clarify the possible mechanism.

KEY FINDINGS

Alternation of Cx43 expression affects cell adhesion and adhesion molecules significantly, such as ZO-1, LFA-1, VLA-4, COX-2 and MCP-1, the mechanism of which is relative with Cx43 influencing the activation of PI3K/AKT/NF-κB signaling pathway. Preconditioning with propofol at its clinically relevant anesthesia concentration attenuates cell adhesion. Propofol not only decreases Cx43 expression in U937 monocytes, but also depresses the activation of PI3K/AKT/NF-κB signaling pathway.

SIGNIFICANCE

Modulation Cx43 expression in U937 monocytes could affect cell adhesion via regulating the activation of PI3K/AKT/NF-κB signaling pathway. Propofol attenuates cell adhesion via inhibiting Cx43 and its downstream signaling pathway of PI3K/AKT/NF-κB.

Functional Genomics for the Identification of Modulators of Platelet-Dependent Thrombus Formation

Despite the absence of the genome in platelets, transcription profiling provides important insights into platelet function and can help clarify abnormalities in platelet disorders. The Bloodomics Consortium performed whole-genome expression analysis comparing in vitro–differentiated megakaryocytes (MKs) with in vitro–differentiated erythroblasts and different blood cell types. This allowed the identification of genes with upregulated expression in MKs compared with all other cell lineages, among the receptors BAMBI, LRRC32, ESAM, and DCBLD2. In a later correlative analysis of genome-wide platelet RNA expression with interindividual human platelet reactivity, LLRFIP and COMMD7 were additionally identified. A functional genomics approach using morpholino-based silencing in zebrafish identified various roles for all of these selected genes in thrombus formation. In this review, we summarize the role of the six identified genes in zebrafish and discuss how they correlate with subsequently performed mouse experiments.

Sirt6 stabilizes atherosclerosis plaques by promoting macrophage autophagy and reducing contact with endothelial cells

Sirt6 has been reported to play a protective role in macrophage foam cell formation, but whether Sirt6 controls atherosclerosis plaque stability and whether it can reduce the interaction between endothelial cells and macrophages remains unclear. The aim of this study was to investigate the effect of Sirt6 on atherosclerosis plaque stability and the underlying mechanisms. We used Tie2-Cre transgenic mice as a Cre-lox tool to delete Sirt6 floxed sequences in endothelial cells during adulthood to establish Sirt6^-/- mice. ApoE^-/-:Sirt6^-/- and ApoE^-/-:Sirt6Tg mice were used in our investigation. After a 16 week high-fat diet, the mice developed markedly atherosclerotic plaques. Sirt6 knockout exacerbated atherosclerotic plaque progression in both size and stability. In vitro, murine macrophage RAW264.7 cells were treated with ox-low density lipoproteins for 24 h to simulate atherosclerosis. Furthermore, Sirt6 overexpression remarkably increased autophagic flux in macrophages and inhibited macrophage apoptosis. Moreover, Sirt6 overexpression inhibited the expression of vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1), and platelet selectin (P-selectin), leading to reduced infiltration of macrophages and foam cells. In conclusion, our study indicates a new mechanism-based strategy to therapeutically stimulate atherosclerosis plaque stability.

Microvascular endothelial function is an independent predictor for albuminuria progression among Asians with type 2 diabetes-A prospective cohort study

OBJECTIVE

We aim to investigate whether microvascular endothelial dysfunction is an independent predictor for future albuminuria progression in T2DM cohort.

METHODS

A total of 1098 patients with T2DM were clinically assessed at baseline and 3.2-year follow-up. Progression was defined as transition from normoalbuminuria (ACR <30 mg/g) to microalbuminuria (ACR = 30-299 mg/g) or macroalbuminuria (ACR >300 mg/g), or microalbuminuria to macroalbuminuria. Microvascular endothelial vasodilation at baseline was quantified using LDF. The increase in perfusion in response to ACh and NaNP was calculated. Logistic regression model was used to estimate the OR for albuminuria progression.

RESULTS

Albuminuria progression occurred in 226 (20.6%) patients. Baseline ACh was significantly higher in nonprogression than progression group (80.0 ± 53.2% vs 72.0 ± 49.7%, P = .04). There is no significant difference in NaNP between the two groups (111.1 ± 80.3% vs 121.1 ± 87.4%, P = .12). After multivariable adjustment, 1-SD increase in ACh was marginally associated with albuminuria progression (OR = 0.87, 95% CI, 0.72-1.02, P = .08) in all patients. When stratified by baseline albuminuria, 1-SD increase in ACh was significantly associated with albuminuria progression in normoalbuminuria (OR = 0.76, 95% CI, 0.59-0.97, P = .03), but not in microalbuminuria patients (OR = 1.18, 95% CI, 0.81-1.70, P = .39).

CONCLUSIONS

Impaired endothelial-dependent microvascular reactivity predicts the onset of albuminuria progression among T2DM patients with normoalbuminuria.

Defenders and Challengers of Endothelial Barrier Function

Regulated vascular permeability is an essential feature of normal physiology and its dysfunction is associated with major human diseases ranging from cancer to inflammation and ischemic heart diseases. Integrity of endothelial cells also play a prominent role in the outcome of surgical procedures and organ transplant. Endothelial barrier function and integrity are regulated by a plethora of highly specialized transmembrane receptors, including claudin family proteins, occludin, junctional adhesion molecules (JAMs), vascular endothelial (VE)-cadherin, and the newly identified immunoglobulin (Ig) and proline-rich receptor-1 (IGPR-1) through various distinct mechanisms and signaling. On the other hand, vascular endothelial growth factor (VEGF) and its tyrosine kinase receptor, VEGF receptor-2, play a central role in the destabilization of endothelial barrier function. While claudins and occludin regulate cell-cell junction via recruitment of zonula occludens (ZO), cadherins via catenin proteins, and JAMs via ZO and afadin, IGPR-1 recruits bullous pemphigoid antigen 1 [also called dystonin (DST) and SH3 protein interacting with Nck90/WISH (SH3 protein interacting with Nck)]. Endothelial barrier function is moderated by the function of transmembrane receptors and signaling events that act to defend or destabilize it. Here, I highlight recent advances that have provided new insights into endothelial barrier function and mechanisms involved. Further investigation of these mechanisms could lead to the discovery of novel therapeutic targets for human diseases associated with endothelial dysfunction.

Soluble endothelial cell-selective adhesion molecule and incident cardiovascular events in a multiethnic population

BACKGROUND

Cell adhesion molecules are key regulators of atherosclerotic plaque development, but circulating levels of soluble fragments, such as intercellular adhesion molecule (sICAM-1) and vascular cell adhesion molecule (sVCAM-1), have yielded conflicting associations with atherosclerotic cardiovascular disease (ASCVD). Endothelial cell-selective adhesion molecule (ESAM) is expressed exclusively in platelets and endothelial cells, and soluble ESAM (sESAM) levels have been associated with prevalent subclinical atherosclerosis. We therefore hypothesized that sESAM would be associated with incident ASCVD.

METHODS

sESAM, sICAM-1, and sVCAM-1 were measured in 2,442 participants without CVD in the Dallas Heart Study, a probability-based population sample aged 30-65 years enrolled between 2000 and 2002. ASCVD was defined as first myocardial infarction, stroke, coronary revascularization, or CV death. A total of 162 ASCVD events were analyzed over 10.4 years.

RESULTS

Increasing sESAM was associated with ASCVD, independent of risk factors (HR Q4 vs Q1: 2.7, 95% CI 1.6-4.6). Serial adjustment for renal function, sICAM-1, VCAM-1, and prevalent coronary calcium did not attenuate these associations. Continuous ESAM demonstrated similar findings (HR 1.31, 95% CI 1.2-1.4). Addition of sESAM to traditional risk factors improved discrimination and reclassification (delta c-index: P = .009; integrated-discrimination-improvement index P = .001; net reclassification index = 0.42, 95% CI 0.15-0.68). Neither sICAM-1 nor sVCAM-1 was independently associated with ASCVD.

CONCLUSIONS

sESAM but not sICAM-1 or sVCAM-1 levels are associated with incident ASCVD. Further studies are warranted to investigate the role of sESAM in ASCVD.

Underlying chronic inflammation alters the profile and mechanisms of acute neutrophil recruitment

Chronically inflamed tissues show altered characteristics that include persistent populations of inflammatory leukocytes and remodelling of the vascular network. As the majority of studies on leukocyte recruitment have been carried out in normal healthy tissues, the impact of underlying chronic inflammation on ongoing leukocyte recruitment is largely unknown. Here, we investigate the profile and mechanisms of acute inflammatory responses in chronically inflamed and angiogenic tissues, and consider the implications for chronic inflammatory disorders. We have developed a novel model of chronic ischaemia of the mouse cremaster muscle that is characterized by a persistent population of monocyte‐derived cells (MDCs), and capillary angiogenesis. These tissues also show elevated acute neutrophil recruitment in response to locally administered inflammatory stimuli. We determined that Gr1^lowMDCs, which are widely considered to have anti‐inflammatory and reparative functions, amplified acute inflammatory reactions via the generation of additional proinflammatory signals, changing both the profile and magnitude of the tissue response. Similar vascular and inflammatory responses, including activation of MDCs by transient ischaemia–reperfusion, were observed in mouse hindlimbs subjected to chronic ischaemia. This response demonstrates the relevance of the findings to peripheral arterial disease, in which patients experience transient exercise‐induced ischaemia known as claudication.These findings demonstrate that chronically inflamed tissues show an altered profile and altered mechanisms of acute inflammatory responses, and identify tissue‐resident MDCs as potential therapeutic targets. © 2016 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Low circulating microRNA levels in heart failure patients are associated with atherosclerotic disease and cardiovascular-related rehospitalizations

OBJECTIVE

Circulating microRNAs (miRNAs) have been implicated in both heart failure and atherosclerotic disease. The aim of this study was to examine associations between heart failure specific circulating miRNAs, atherosclerotic disease and cardiovascular-related outcome in patients with heart failure.

METHODS

The levels of 11 heart failure-specific circulating miRNAs were compared in plasma of 114 heart failure patients with and without different manifestations of atherosclerotic disease. We then studied these miRNAs in relation to biomarkers associated to atherosclerosis and to cardiovascular-related rehospitalizations during 18 months of follow-up.

RESULTS

At least one manifestation of atherosclerotic disease was found in 70 (61%) of the heart failure patients. A consistent trend was found between an increasing number of manifestations of atherosclerosis (peripheral arterial disease in specific), and lower levels of miR-18a-5p, miR-27a-3p, miR-199a-3p, miR-223-3p and miR-652-3p (all P < 0.05). Target prediction and network analyses identified several interactions between miRNA targets and biomarkers related to inflammation, angiogenesis and endothelial dysfunction. Lower miRNA levels were associated with higher levels of these atherosclerosis-related biomarkers. In addition, lower miRNA levels were significantly associated with rehospitalizations due to cardiovascular causes within 18 months, with let-7i-5p as strongest predictor [HR 2.06 (95% CI 1.29-3.28), C-index 0.70, P = 0.002].

CONCLUSIONS

A consistent pattern of lower levels of circulating miRNAs was found in heart failure patients with atherosclerotic disease, in particular peripheral arterial disease. In addition, lower levels of miRNAs were associated with higher levels of biomarkers involved in atherosclerosis and an increased risk of a cardiovascular-related rehospitalization.

Endosulfan induces autophagy and endothelial dysfunction via the AMPK/mTOR signaling pathway triggered by oxidative stress

Cardiovascular diseases is related to environmental pollution. Endosulfan is an organochlorine pesticide and its toxicity has been reported. However, the relationship between oxidative stress and autophagy induced by endosulfan and its underlying mechanism remain confusing. In this study, human umbilical vein endothelial cells (HUVECs) were chosen to explore the toxicity mechanism and were treated with 0, 1, 6, 12 μg/mL^-1 endosulfan for 24 h, respectively. The present results showed that autophagy could be induced by endosulfan, which was verified by the monodansylcadaverine staining, autophagic ultrastructural observation, and LC3-I/LC3-II conversion. In addition, the levels of adenosine triphosphate (ATP), the mitochondria membrane potential (MMP) were significantly decreased in a dose-dependent way. The expression of proinflammatory cytokines (tumor necrosis factor α, interleukin-1β, and interleukin-6) were significantly elevated, and the index of endothelial function such as monocyte chemotactic protein 1 (MCP-1), intercellular cell adhesion molecule-1 (ICAM-1) increased. Moreover, endosulfan had an activation effect on the 5'AMP-activated protein kinase (AMPK)/rapamycin (mTOR) signaling pathway. Our findings demonstrated that endosulfan could induce oxidative stress and mitochondria injury, activate autophagy, induce inflammatory response, and eventually lead to endothelial dysfunction via the AMPK/mTOR pathway. This indicates that exposure to endosulfan is a potential risk factor for cardiovascular diseases.

Atorvastatin attenuates p‑cresyl sulfate‑induced atherogenesis and plaque instability in ApoE knockout mice

p-cresyl sulfate (PCS) is a protein-bound uremic toxin retained in the blood of patients with chronic kidney disease (CKD) As atherosclerosis is a primary cardiovascular complication for patients with CKD, the aim of the present study was to investigate the mechanisms underlying the aggravation of atherosclerosis by PCS. In addition, the effect of atorvastatin was assessed in reversing the effects of PCS. PCS was revealed to promote the initiation and progression of atherosclerosis. Following treatment with atorvastatin, apolipoprotein E knockout mice demonstrated a reduction in PCS-induced atherogenesis and plaque vulnerability. In addition, atorvastatin decreased the protein expression levels of vascular cell adhesion molecule-1 and intercellular cell adhesion molecule-1, and the interaction between leukocytes and endothelia. The plasma lipid profiles of mice were not significantly affected by gavage of low-dose atorvastatin. The results of the present study indicate that PCS promotes plaque growth and instability by enhancing leukocyte-endothelium interaction, and that these effects may be attenuated by atorvastatin treatment.

Plasma Membrane Profiling Reveals Upregulation of ABCA1 by Infected Macrophages Leading to Restriction of Mycobacterial Growth

The plasma membrane represents a critical interface between the internal and extracellular environments, and harbors multiple proteins key receptors and transporters that play important roles in restriction of intracellular infection. We applied plasma membrane profiling, a technique that combines quantitative mass spectrometry with selective cell surface aminooxy-biotinylation, to Bacille Calmette–Guérin (BCG)-infected THP-1 macrophages. We quantified 559 PM proteins in BCG-infected THP-1 cells. One significantly upregulated cell-surface protein was the cholesterol transporter ABCA1. We showed that ABCA1 was upregulated on the macrophage cell-surface following infection with pathogenic mycobacteria and knockdown of ABCA1 resulted in increased mycobacterial survival within macrophages, suggesting that it may be a novel mycobacterial host-restriction factor.

Mutually Supportive Mechanisms of Inflammation and Vascular Remodeling

Chronic inflammation is often accompanied by angiogenesis, the development of new blood vessels from existing ones. This vascular response is a response to chronic hypoxia and/or ischemia, but is also contributory to the progression of disorders including atherosclerosis, arthritis, and tumor growth. Proinflammatory and proangiogenic mediators and signaling pathways form a complex and interrelated network in these conditions, and many factors exert multiple effects. Inflammation drives angiogenesis by direct and indirect mechanisms, promoting endothelial proliferation, migration, and vessel sprouting, but also by mediating extracellular matrix remodeling and release of sequestered growth factors, and recruitment of proangiogenic leukocyte subsets. The role of inflammation in promoting angiogenesis is well documented, but by facilitating greater infiltration of leukocytes and plasma proteins into inflamed tissues, angiogenesis can also propagate chronic inflammation. This review examines the mutually supportive relationship between angiogenesis and inflammation, and considers how these interactions might be exploited to promote resolution of chronic inflammatory or angiogenic disorders.

Endothelial Cell-Selective Adhesion Molecule Expression in Hematopoietic Stem/Progenitor Cells Is Essential for Erythropoiesis Recovery after Bone Marrow Injury

Numerous red blood cells are generated every second from proliferative progenitor cells under a homeostatic state. Increased erythropoietic activity is required after myelo-suppression as a result of chemo-radio therapies. Our previous study revealed that the endothelial cell-selective adhesion molecule (ESAM), an authentic hematopoietic stem cell marker, plays essential roles in stress-induced hematopoiesis. To determine the physiological importance of ESAM in erythroid recovery, ESAM-knockout (KO) mice were treated with the anti-cancer drug, 5-fluorouracil (5-FU). ESAM-KO mice experienced severe and prolonged anemia after 5-FU treatment compared to wild-type (WT) mice. Eight days after the 5-FU injection, compared to WT mice, ESAM-KO mice showed reduced numbers of erythroid progenitors in bone marrow (BM) and spleen, and reticulocytes in peripheral blood. Megakaryocyte-erythrocyte progenitors (MEPs) from the BM of 5-FU-treated ESAM-KO mice showed reduced burst forming unit-erythrocyte (BFU-E) capacities than those from WT mice. BM transplantation revealed that hematopoietic stem/progenitor cells from ESAM-KO donors were more sensitive to 5-FU treatment than that from WT donors in the WT host mice. However, hematopoietic cells from WT donors transplanted into ESAM-KO host mice could normally reconstitute the erythroid lineage after a BM injury. These results suggested that ESAM expression in hematopoietic cells, but not environmental cells, is critical for hematopoietic recovery. We also found that 5-FU treatment induces the up-regulation of ESAM in primitive erythroid progenitors and macrophages that do not express ESAM under homeostatic conditions. The phenotypic change seen in macrophages might be functionally involved in the interaction between erythroid progenitors and their niche components during stress-induced acute erythropoiesis. Microarray analyses of primitive erythroid progenitors from 5-FU-treated WT and ESAM-KO mice revealed that various signaling pathways, including the GATA1 system, were impaired in ESAM-KO mice. Thus, our data demonstrate that ESAM expression in hematopoietic progenitors is essential for erythroid recovery after a BM injury.

Potential contributions of intimal and plaque hypoxia to atherosclerosis

Injury of arterial endothelium by abnormal shear stress and other insults induces migration and proliferation of vascular smooth muscle cells (VSMCs), which in turn leads to intimal thickening, hypoxia, and vasa vasorum angiogenesis. The resultant new blood vessels extend from the tunica media into the outer intima, allowing blood-borne oxidized low-density lipoprotein (oxLDL) particles to accumulate in outer intimal tissues by extravasation through local capillaries. In response to oxLDL accumulation, monocytes infiltrate into arterial wall tissues, where they differentiate into macrophages and subsequently evolve into foam cells by uptaking large quantities of oxLDL particles, the latter process being stimulated by hypoxia. Increased oxygen demand due to expanding macrophage and foam cell populations contributes to persistent hypoxia in plaque lesions, whereas hypoxia further promotes plaque growth by stimulating angiogenesis, monocyte infiltration, and oxLDL uptake into macrophages. Molecularly, the accumulation of hypoxia-inducible factor (HIF)-1α and the expression of its target genes mediate many of the hypoxia-induced processes during plaque initiation and growth. It is hoped that further understanding of the underlying mechanisms may lead to novel therapies for effective intervention of atherosclerosis.

Soluble endothelial cell selective adhesion molecule and cardiovascular outcomes in patients with stable coronary disease: A report from the Heart and Soul Study

BACKGROUND AND AIMS

Endothelial cell-selective adhesion molecule (ESAM) is selectively expressed on vascular endothelium and is postulated to play a role in atherogenesis. We investigated the association of serum soluble ESAM (sESAM) levels with subsequent cardiovascular outcomes in patients with stable ischemic heart disease.

METHODS

We measured sESAM levels in 981 patients with stable coronary disease enrolled between September 2000 and December 2002 in a prospective cohort study. Poisson regression models were used to define the relationship between baseline sESAM levels and cardiovascular outcomes, including myocardial infarction, heart failure hospitalization, and mortality.

RESULTS

There were 293 occurrences of the composite endpoint over a median follow-up of 8.9 years. After adjusting for demographic and clinical risk factors, participants in the highest sESAM quartile (compared to the lower three sESAM quartiles) had a higher rate of the composite endpoint (incident rate ratio (IRR) 1.52 (95% CI 1.16-1.99) as well as of its individual components: myocardial infarction (IRR 1.64 (1.06-2.55)), heart failure hospitalizations (IRR 1.96 (1.32-2.81)), and death (IRR 1.5 (1.2-1.89)). These associations were no longer significant after adjustment for estimated glomerular filtration rate.

CONCLUSIONS

sESAM levels associate with myocardial infarction, heart failure, and death after adjustment for demographic and clinical risk factors, but not after adjustment for kidney function. sESAM may be involved in the pathogenesis of concurrent kidney and cardiovascular disease.

ESAM predicts cardiovascular mortality in diabetic hemodialysis patients

AIM

To assess endothelial cell selective adhesion molecule (ESAM) as predictor of cardiovascular mortality in diabetic dialysis patients (DDPs).

METHODS

ESAM, clinical and laboratory parameters were assessed in 73 DDP. Cardiovascular mortality was recorded in a 2 years' prospective observational study.

RESULTS

Baseline ESAM was 17.1 (10.05-24.8) ng/ml and was correlated to phosphate (r = -0.42, p = 0.008), parathormone (r = -0.36, p = 0.048), albumin (r = -0.24, p = 0.048). ESAM significantly predicted cardiovascular death in univariate [HR = 1.03, 95% CI (1.006-1.054), p = 0.01] and multivariate [HR = 1.034, 95% CI (1.003-1.066), p = 0.03] Cox analysis. Time to cardiovascular death was shorter for patients with ESAM >12.44 ng/ml, p = 0.0045.

CONCLUSION

ESAM is an independent predictor of cardiovascular mortality in DDP.

Silica nanoparticles enhance autophagic activity, disturb endothelial cell homeostasis and impair angiogenesis

Background

Given that the effects of ultrafine fractions (<0.1 μm) on ischemic heart diseases (IHD) and other cardiovascular diseases are gaining attention, this study is aimed to explore the influence of silica nanoparticles (SiNPs)-induced autophagy on endothelial cell homeostasis and angiogenesis.

Methods and results

Ultrastructural changes of autophagy were observed in both vascular endothelial cells and pericytes in the heart of ICR mice by TEM. Autophagic activity and impaired angiogenesis were further confirmed by the immunohistochemistry staining of LC3 and VEGFR2. In addition, the immunohistochemistry results showed that SiNPs had an inhibitory effect on ICAM-1 and VCAM-1, but no obvious effect on E-selectin in vivo. The disruption of F-actin cytoskeleton occurred as an initial event in SiNPs-treated endothelial cells. The depolarized mitochondria, autophagic vacuole accumulation, LC3-I/LC3-II conversion, and the down-regulation of cellular adhesion molecule expression were all involved in the disruption of endothelial cell homeostasis in vitro. Western blot analysis indicated that the VEGFR2/PI3K/Akt/mTOR and VEGFR2/MAPK/Erk1/2/mTOR signaling pathway was involved in the cardiovascular toxicity triggered by SiNPs. Moreover, there was a crosstalk between the VEGFR2-mediated autophagy signaling and angiogenesis signaling pathways.

Conclusions

In summary, the results demonstrate that SiNPs induce autophagic activity in endothelial cells and pericytes, subsequently disturb the endothelial cell homeostasis and impair angiogenesis. The VEGFR2-mediated autophagy pathway may play a critical role in maintaining endothelium and vascular homeostasis. Our findings may provide experimental evidence and explanation for cardiovascular diseases triggered by nano-sized particles.

Electronic supplementary material

The online version of this article (doi:10.1186/s12989-014-0050-8) contains supplementary material, which is available to authorized users.

TLR4-mediated expression of Mac-1 in monocytes plays a pivotal role in monocyte adhesion to vascular endothelium

Toll-like receptor 4 (TLR4) is known to mediate monocyte adhesion to endothelial cells, however, its role on the expression of monocyte adhesion molecules is unclear. In the present study, we investigated the role of TLR4 on the expression of monocyte adhesion molecules, and determined the functional role of TLR4-induced adhesion molecules on monocyte adhesion to endothelial cells. When THP-1 monocytes were stimulated with Kdo2-Lipid A (KLA), a specific TLR4 agonist, Mac-1 expression was markedly increased in association with an increased adhesion of monocytes to endothelial cells. These were attenuated by anti-Mac-1 antibody, suggesting a functional role of TLR4-induced Mac-1 on monocyte adhesion to endothelial cells. In monocytes treated with MK886, a 5-lipoxygenase (LO) inhibitor, both Mac-1 expression and monocyte adhesion to endothelial cells induced by KLA were markedly attenuated. Moreover, KLA increased the expression of mRNA and protein of 5-LO, suggesting a pivotal role of 5-LO on these processes. In in vivo studies, KLA increased monocyte adhesion to aortic endothelium of wild-type (WT) mice, which was attenuated in WT mice treated with anti-Mac-1 antibody as well as in TLR4-deficient mice. Taken together, TLR4-mediated expression of Mac-1 in monocytes plays a pivotal role on monocyte adhesion to vascular endothelium, leading to increased foam cell formation in the development of atherosclerosis.

JAM-related proteins in mucosal homeostasis and inflammation

Mucosal surfaces are lined by epithelial cells that form a physical barrier protecting the body against external noxious substances and pathogens. At a molecular level, the mucosal barrier is regulated by tight junctions (TJs) that seal the paracellular space between adjacent epithelial cells. Transmembrane proteins within TJs include junctional adhesion molecules (JAMs) that belong to the cortical thymocyte marker for Xenopus family of proteins. JAM family encompasses three classical members (JAM-A, JAM-B, and JAM-C) and related molecules including JAM4, JAM-like protein, Coxsackie and adenovirus receptor (CAR), CAR-like membrane protein and endothelial cell-selective adhesion molecule. JAMs have multiple functions that include regulation of endothelial and epithelial paracellular permeability, leukocyte recruitment during inflammation, angiogenesis, cell migration, and proliferation. In this review, we summarize the current knowledge regarding the roles of the JAM family members in the regulation of mucosal homeostasis and leukocyte trafficking with a particular emphasis on barrier function and its perturbation during pathological inflammation.

Adhesion molecule CD146 and its soluble form correlate well with carotid atherosclerosis and plaque instability

AIMS

Intraplaque neovascularization and foam cell infiltration contribute to the development of unstable plaque, leading to thromboembolism and stroke. Cell adhesion molecules (CAMs) have been reported to be involved in the progression of atherosclerosis and plaque vulnerability. The aim of this study was to assess the association of adhesion molecule CD146 with carotid plaque instability.

METHODS

We collected forty atherosclerotic plaques from 40 patients undergoing carotid endarterectomy. The clinical information of each patient was obtained, and the plaque morphology and characteristics were examined by the ultrasound. The CD146 expressions of the plaques were graded by using semiquantitative scales. The serum level of soluble form of CD146 was detected by enzyme-linked immunosorbent assay (ELISA).

RESULTS

CD146 expression was mainly on the intraplaque blood vessels and infiltrated macrophages. The CD146 expression was strongly correlated with the matrix metalloproteinase-9(MMP-9)expressions (P < 0.001) in the plaques. Soluble CD146 (sCD146) was also elevated in patients with atherosclerotic plaques. There was significant correlation between the increased CD146 expression and sCD146 level (P = 0.0057). sCD146 correlated well with serum MMP-9 (P < 0.0044), IL-6 (P = 0.0044) and high sensitivity C-reactive protein (hsCRP) (P = 0.005).

CONCLUSIONS

Adhesion molecules CD146 and its soluble form strongly correlated with the development of inflammation of atherosclerosis and plaque instability. CD146 may be a promising biomarker for monitoring the development and instability of atherosclerotic plaque in patients with carotid diseases.

Identification of a cytoplasmic linker protein as a potential target for neovascularization

OBJECTIVE

Atherosclerosis and other cardiovascular diseases are serious threats to human health and become the leading cause of death in the world. Emerging evidence reveals that inhibition of plaque neovascularization could be an effective approach for the treatment of atherosclerosis. This study was conducted to identify cytoplasmic linker protein 170 as a potential target for cardiovascular diseases through modulation of neovascularization.

METHODS AND RESULTS

Immunofluorescence microscopy revealed that cytoplasmic linker protein 170 was ubiquitously expressed in mouse kidney, liver, lung, normal non-atherosclerotic aorta, and atherosclerotic aorta and was partly localized in the vascular endothelium. siRNAs were introduced to human umbilical vein endothelial cells (HUVECs) and the effect of knockdown was confirmed by Western blotting. Vascularization study was assessed with matrigel-based capillary assembly, branching, and in vivo matrigel plug assays. The data showed that siRNA-mediated knockdown of the cytoplasmic linker protein remarkably compromised the assembly and branching of capillary-like blood vessels and neovascularization in vivo. Cell motility and polarity properties were then analyzed using scratch wound repair, boyden chamber, and immunofluorescence assays, and the results revealed that the cytoplasmic linker protein was critical for the motility abilities of HUVECs through its actions on cell polarity.

CONCLUSION

Both in vitro and in vivo studies demonstrate the significance of the cytoplasmic linker protein for blood vessel formation. Mechanistic investigation reveals that its effect on neovascularization is orchestrated through its regulation of vascular endothelial cell polarity and motility. These findings provide the basis for exploring effective approaches to regulate neovascularization in cardiovascular diseases.

Role of soluble endothelial cell-selective adhesion molecule biomarker in albuminuria and kidney function changes in patients with coronary artery disease: the Heart and Soul Study

OBJECTIVE

Endothelial dysfunction is a possible mechanism to explain the association between atherosclerosis and kidney disease. This study evaluated circulating soluble endothelial cell-selective adhesion molecule (sESAM), a marker of endothelial dysfunction, as a risk factor for kidney function decline and albuminuria.

APPROACH AND RESULTS

In the Heart and Soul Study, we measured sESAM from baseline serum samples and defined elevated levels of sESAM by the highest quartile (quartile 4 [Q4]: >65.4 ng/mL). We evaluated the associations of high sESAM with baseline estimated glomerular filtration rate (eGFR) and ratio of urine albumin to creatinine (ACR), and with longitudinal changes in eGFR and ACR. Among 990 participants with sESAM measurements, median sESAM was 54.5 ng/mL (interquartile range, 45.3-65.8). After multivariable adjustment, elevated levels of sESAM were strongly and independently associated with baseline reduced eGFR <60 mL/min per 1.73 m(2) (odds ratio [OR], 11.44; P<0.0001) and ACR ≥30 mg/g (OR, 5.23; P<0.0001). Associations of sESAM (Q4 versus quartile 1 [Q1]) with change in ACR (β=54.47; P<0.0001) were also significant after full adjustment. The association with change in eGFR (1.56%; P=0.0049) was not statistically significant after application of the Bonferroni correction for multiple markers. In unadjusted models, sESAM was associated with rapid kidney function loss, defined as 3% annual eGFR decline (OR, 2.28; P=0.0003), although this was attenuated by adjustment (OR, 2.11; P=0.0095).

CONCLUSIONS

sESAM is associated with albuminuria and reduced kidney function in both cross-sectional and longitudinal analyses. These findings implicate endothelial dysfunction as a potential contributor to the elevated kidney disease risk in persons with cardiovascular disease.

Endothelial junction regulation: a prerequisite for leukocytes crossing the vessel wall

The leukocytes of the innate immune system, especially neutrophils and monocytes, exit the circulation early in the response to local inflammation and infection. This is necessary to control and prevent the spread of infections before an adaptive immune response can be raised. The endothelial cells and the intercellular junctions that connect them form a barrier that leukocytes need to pass in order to get to the site of inflammation. The junctions are tightly regulated which ensures that leukocytes only exit when and where they are needed. This regulation is disturbed in many chronic inflammatory diseases which are characterized by ongoing recruitment and interstitial accumulation of leukocytes. In this review, we summarize the molecular mechanisms that regulate endothelial cell-cell junctions and prevent or permit leukocyte transendothelial migration.

Low serum endothelial cell-selective adhesion molecule predicts increase in albuminuria in type 2 diabetes patients

PURPOSE

The newly discovered endothelial cell-selective adhesion molecule (ESAM) stabilizes the interendothelial tight junction; it circulates in serum as a soluble fraction. In experimental diabetes, reduced ESAM expression in the kidney is associated with albuminuria. We investigated, for the first time, serum ESAM as a predictor of progression of kidney disease in type 2 diabetes (T2D).

METHODS

T2D non-nephrotic patients with glomerular filtration rate (GFR) > 30 ml/min were included. History, medication and laboratory evaluation were assessed at inclusion and the end of study; ESAM was determined at baseline.

RESULTS

Eighty-eight patients--mean age 63 ± 10.84 years, 49 (55.68 %) males--were prospectively followed up for 20 months. Baseline GFR was 76.37 ± 29.56 ml/min, and urinary albumin/creatinine ratio (UACR) 21.63(7.08-94.52) mg/g; ESAM was 12.85(6.13-19.83) ng/ml. Difference (Δ) in UACR between end of study and baseline was inversely related to serum albumin (r = -0.27, p = 0.017) and ESAM (r = -0.21, p = 0.047); ΔGFR correlated to glycated hemoglobin (r = 0.22, p = 0.05). In multiple regression, introducing variables susceptible to influence progression of kidney disease, ΔUACR was significantly related to log ESAM (p = 0.005) and ΔGFR to glycated hemoglobin (p = 0.016).

CONCLUSION

Serum ESAM is a predictor of worsening of albuminuria in T2D patients without advanced kidney disease.

Endothelial cell-selective adhesion molecule in diabetic nephropathy

BACKGROUND

Endothelial cell-selective adhesion molecule (ESAM) contributes to the integrity of tight junctions and modulates endothelial function. ESAM has been linked to experimental diabetic nephropathy; its soluble fraction is related to atherosclerosis in humans. In this cross-sectional observational study, we describe for the first time serum ESAM in type 2 diabetic patients with different stages of chronic kidney disease (CKD) and its relationship to vascular endothelial growth factor-A (VEGF-A). Materials and methods  We included diabetic patients with different stages of CKD and controls. History, laboratory evaluation, serum ESAM and VEGF-A and urinary albumin/creatinine ratio were obtained.

RESULTS

Endothelial cell-selective adhesion molecule was higher in non-CKD diabetic patients 13.80 (6.15-18.70) ng/mL (n=45) than controls 7.30 (4.60-9.40) ng/mL (n=48), P=0.001. VEGF-A had a similar pattern: 71.3 (54.75-120.70) vs. 43.20 (30.1-65.90) pg/mL, P<0.0001. ESAM was 10.4 (5.6-17.4) ng/mL in predialysis CKD patients (n=59) and 22.35 (8.55-29.95) ng/mL in dialysis patients (n=36), P<0.001. Patients with glomerular filtration rate (GFR)<15 mL/min had the highest ESAM (P=0.003). ESAM was similar in normoalbuminuric, microalbuminuric and proteinuric patients. ESAM was directly correlated with the duration of diabetes (r(2)=0.048, P=0.009), C-reactive protein (r(2)=0.028, P=0.05), VEGF-A (r(2)=0.040, P=0.01) and inversely with HbA1C (r(2)=0.036, P=0.03), haemoglobin (r(2)=0.062, P=0.005) and albumin (r(2)=0.0·40, P=0.026). In multiple regression diabetes duration, HbA1C and VEGF-A were significant predictors of ESAM. In controls, ESAM was inversely related to VEGF (r(2)=037, P=0.01).

CONCLUSION

Endothelial cell-selective adhesion molecule and VEGF-A are higher in patients with diabetes than in controls. The highest ESAM is found in dialysis patients. ESAM correlates with diabetes duration and control, inflammation and VEGF-A in patients with diabetes, but not in controls.

Vascular effects of phytoestrogens and alternative menopausal hormone therapy in cardiovascular disease

Phytoestrogens are estrogenic compounds of plant origin classified into different groups including isoflavones, lignans, coumestans and stilbenes. Isoflavones such as genistein and daidzein are the most studied and most potent phytoestrogens, and are found mainly in soy based foods. The effects of phytoestrogens are partly mediated via estrogen receptors (ERs): ERα, ERβ and possibly GPER. The interaction of phytoestrogens with ERs is thought to induce both genomic and non-genomic effects in many tissues including the vasculature. Some phytoestrogens such as genistein have additional non-ER-mediated effects involving signaling pathways such as tyrosine kinase. Experimental studies have shown beneficial effects of phytoestrogens on endothelial cells, vascular smooth muscle, and extracellular matrix. Phytoestrogens may also affect other pathophysiologic vascular processes such as lipid profile, angiogenesis, inflammation, tissue damage by reactive oxygen species, and these effects could delay the progression of atherosclerosis. As recent clinical trials showed no vascular benefits or even increased risk of cardiovascular disease (CVD) and CV events with conventional menopausal hormone therapy (MHT), phytoestrogens are being considered as alternatives to pharmacologic MHT. Epidemiological studies in the Far East population suggest that dietary intake of phytoestrogens may contribute to the decreased incidence of postmenopausal CVD and thromboembolic events. Also, the WHO-CARDIAC study supported that consumption of high soybean diet is associated with lower mortalities from coronary artery disease. However, as with estrogen, there has been some discrepancy between the experimental studies demonstrating the vascular benefits of phytoestrogens and the data from clinical trials. This is likely because the phytoestrogens clinical trials have been limited in many aspects including the number of participants enrolled, the clinical end points investigated, and the lack of long-term follow-up. Further investigation of the cellular mechanisms underlying the vascular effects of phytoestrogens and careful evaluation of the epidemiological evidence and clinical trials of their potential vascular benefits would put forward the use of phytoestrogens as an alternative MHT for the relief of menopausal symptoms and amelioration of postmenopausal CVD.