Nuclear factor-kappaB immunoreactivity is present in human coronary plaque and enhanced in patients with unstable angina pectoris

E-Cigarettes induce expression of procoagulant tissue factor in cultivated human endothelial cells

BACKGROUND

E-cigarettes (ECIG) are proposed as an alternative for regular tobacco users with less dangerous effects for health. Several studies demonstrated that ECIG exert deleterious cardiovascular effects and promote platelet dependent thrombosis. However, ECIG role on Tissue Factor-dependent thrombosis is still unknown. Dysfunctional endothelial cells (ECs) are known to express Tissue Factor (TF) on their surface. Aim of the present study was to investigate whether ECIG might promote TF expression in ECs, shifting them to a pro thrombotic phenotype.

METHODS

Human Umbilical Vein Endothelial Cells (HUVEC) were incubated with increasing doses of ECIG (commercially available and mix of propylene glycol/vegetable glycerine/nicotine 18 mg/mL) up to 1.8 mg/mL. TF gene expression and protein levels were assessed at different time points by Real Time PCR and Western Blot, respectively. TF surface expression and activity were also measured by FACS analysis and coagulation assay. Finally, NF-kB translocation was investigated as possible mechanism of action. Potential protective effects by Rosuvastatin were also investigated.

RESULTS

ECIG significantly increased TF expression at both gene and protein levels in a time and dose dependent manner. Surface expression and procoagulant activity were increased as well. These phenomena appeared modulated by the NF-κB pathway. Rosuvastatin reduced ECIG effects on TF-mRNA.

CONCLUSIONS

Although in vitro, we indicate that ECIG promote a pro thrombotic phenotype in ECs via expression of functional TF. Data of the present study permit to shed a brighter light on the still partially unresolved issue about the role of ECIG in development of cardiovascular diseases suggesting that they might represent a potential risk factor for thrombotic cardiovascular events.

Uric Acid Induces a Proatherothrombotic Phenotype in Human Endothelial Cells by Imbalancing the Tissue Factor/Tissue Factor Pathway Inhibitor Pathway

BACKGROUND

 Several evidence show that elevated plasma levels of uric acid (UA) are associated with the increased risk of developing atherothrombotic cardiovascular events. Hyperuricemia is a risk factor for endothelial dysfunction (ED). ED is involved in the pathophysiology of atherothrombosis since dysfunctional cells lose their physiological, antithrombotic properties. We have investigated whether UA might promote ED by modulating the tissue factor (TF)/TF pathway inhibitor (TFPI) balance by finally changing the antithrombotic characteristics of endothelial cells.

METHODS

 Human umbilical vein endothelial cells were incubated with increasing doses of UA (up to 9 mg/dL). TF gene and protein expressions were evaluated by real-time polymerase chain reaction (PCR) and Western blot. Surface expression and procoagulant activity were assessed by FACS (fluorescence activated cell sorting) analysis and coagulation assay. The mRNA and protein levels of TFPI were measured by real-time PCR and Western blot. The roles of inflammasome and nuclear factor-κB (NF-κB) as possible mechanism(s) of action of the UA on TF/TFPI balance were also investigated.

RESULTS

 UA significantly increased TF gene and protein levels, surface expression, and procoagulant activity. In parallel, TFPI levels were significantly reduced. The NF-κB pathways appeared to be involved in modulating these phenomena. Additionally, inflammasome might also play a role.

CONCLUSION

 The present in vitro study shows that one of the mechanisms by which high levels of UA contribute to ED might be the imbalance between TF/TFPI levels in endothelial cells, shifting them to a nonphysiological, prothrombotic phenotype. These UA effects might hypothetically explain, at least in part, the relationship observed between elevated plasma levels of UA and cardiovascular events.

Effects of diet-induced hypercholesterolemia and gold nanoparticles treatment on peripheral tissues

Cholesterol is a lipid molecule of great biological importance to animal cells. Dysregulation of cholesterol metabolism leads to raised blood total cholesterol levels, a clinical condition called hypercholesterolemia. Evidence has shown that hypercholesterolemia is associated with the development of liver and heart disease. One of the mechanisms underlying heart and liver alterations induced by hypercholesterolemia is oxidative stress. In this regard, in several experimental studies, gold nanoparticles (AuNP) displayed antioxidant properties. We hypothesized that hypercholesterolemia causes redox system imbalance in the liver and cardiac tissues, and AuNP treatment could ameliorate it. Young adult male Swiss mice fed a regular rodent diet or a high cholesterol diet for eight weeks and concomitantly treated with AuNP (2.5 μg/kg) or vehicle by oral gavage. Hypercholesterolemia increased the nitrite concentration and glutathione (GSH) levels and decreased the liver's superoxide dismutase (SOD) activity. Also, hypercholesterolemia significantly enhanced the reactive oxygen species (ROS) and GSH levels in cardiac tissue. Notably, AuNP promoted the redox system homeostasis, increasing the SOD activity in hepatic tissue and reducing ROS levels in cardiac tissue. Overall, our data showed that hypercholesterolemia triggered oxidative stress in mice's liver and heart, which was partially prevented by AuNP treatment.

Effects of colchicine on tissue factor in oxLDL-activated T-lymphocytes

Several studies have shown that T-cells might be involved in pathophysiology of acute coronary syndromes (ACS). Tissue factor (TF) plays a key role in ACS. Many evidences have indicated that some statins reduce TF expression in several cell types. However, literature about rosuvastatin and TF and about statins effects on T-cells is still scanty. Colchicine is an anti-inflammatory drug recently proven to have beneficial effects in ACS via unknown mechanisms. This study investigates the effects of colchicine and rosuvastatin on TF expression in oxLDL-activated T-cells. T-cells, isolated from buffy coats of healthy volunteers, were stimulated with oxLDL (50 µg/dL). T-cells were pre-incubated with colchicine (10 µM) or rosuvastatin (5 µM) for 1 h and then stimulated with oxLDL (50 μg/mL). TF gene (RT-PCR), protein (western blot), surface expression (FACS) and procoagulant activity (FXa generation assay) were measured. NF-κB/IκB axis was examined by western blot analysis and translocation assay. Colchicine and rosuvastatin significantly reduced TF gene, and protein expression and procoagulant activity in oxLDL stimulated T-cells. This effect was associated with a significant reduction in TF surface expression as well as its procoagulant activity. These phenomena appear modulated by drug effects on the transcription factor NF-kB. Rosuvastatin and colchicine prevent TF expression in oxLDL-stimulated T-cells by modulating the NF-κB/IκB axis. Thus, we speculate that this might be another mechanism by which these drugs exert benefic cardiovascular effects.

Anti-Inflammatory Drugs in Patients with Ischemic Heart Disease

Inflammation has long been known to play a role in atherogenesis and plaque complication, as well as in some drugs used in therapy for atherosclerotic disease, such as statins, acetylsalicylic acid, and modulators of the renin-angiotensin system, which also have anti-inflammatory effects. Furthermore, inflammatory biomarkers have been demonstrated to predict the incidence of cardiovascular events. In spite of this, and with the exception of acetylsalicylic acid, non-steroidal anti-inflammatory drugs are unable to decrease the incidence of cardiovascular events and may even be harmful to the cardiovascular system. In recent years, other anti-inflammatory drugs, such as canakinumab and colchicine, have shown an ability to reduce the incidence of cardiovascular events in secondary prevention. Colchicine could be a potential candidate for use in clinical practice given its safety and low price, although the results of temporary studies require confirmation in large randomized clinical trials. In this paper, we discuss the evidence linking inflammation with atherosclerosis and review the results from various clinical trials performed with anti-inflammatory drugs. We also discuss the potential use of these drugs in routine clinical settings.

Investigating the multi-target pharmacological mechanism of danhong injection acting on unstable angina by combined network pharmacology and molecular docking

Background

Danhong injection (DHI), which is one of the most well-known Traditional Chinese Medicine (TCM) injections, widely used to treat unstable angina (UA). However, its underlying pharmacological mechanisms need to be further clarified.

Methods

In the present study, network pharmacology was adopted. Firstly, the relative compounds were obtained by a wide-scaled literatures-mining and potential targets of these compounds by target fishing were collected. Then, we built the UA target database by DisGeNET, DigSee, TTD, OMIM. Based on data, protein-protein interaction (PPI) analysis, GO and KEGG pathway enrichment analysis were performed and screen the hub targets by topology. Furthermore, evaluation of the binding potential of key targets and compounds through molecular docking.

Results

The results showed that 12 ingredients of DHI and 27 putative known therapeutic targets were picked out. By systematic analysis, identified 4 hub targets (TNF, TLR4, NFKB1 and SERPINE1) mainly involved in the complex treating effects associated with coagulation and hemostasis, cell membrane region, platelet alpha granule, NF-kappa B signaling pathway and TNF signaling pathway.

Conclusion

The results of this study preliminarily explained the potential targets and signaling pathways of DHI in the treatment of UA, which may help to laid a good foundation for experimental research and further clinical application.

Neutrophil microvesicles drive atherosclerosis by delivering miR-155 to atheroprone endothelium

Neutrophils are implicated in the pathogenesis of atherosclerosis but are seldom detected in atherosclerotic plaques. We investigated whether neutrophil-derived microvesicles may influence arterial pathophysiology. Here we report that levels of circulating neutrophil microvesicles are enhanced by exposure to a high fat diet, a known risk factor for atherosclerosis. Neutrophil microvesicles accumulate at disease-prone regions of arteries exposed to disturbed flow patterns, and promote vascular inflammation and atherosclerosis in a murine model. Using cultured endothelial cells exposed to disturbed flow, we demonstrate that neutrophil microvesicles promote inflammatory gene expression by delivering miR-155, enhancing NF-κB activation. Similarly, neutrophil microvesicles increase miR-155 and enhance NF-κB at disease-prone sites of disturbed flow in vivo. Enhancement of atherosclerotic plaque formation and increase in macrophage content by neutrophil microvesicles is dependent on miR-155. We conclude that neutrophils contribute to vascular inflammation and atherogenesis through delivery of microvesicles carrying miR-155 to disease-prone regions.

Nrf2, NF-κB and PPARβ/δ mRNA Expression Profile in Patients with Coronary Artery Disease

BACKGROUND

Oxidative stress and inflammation are present in coronary artery disease (CAD) and are linked to the activation of the transcription nuclear factor kappa B (NF-κB). To attenuate these complications, transcription factors like nuclear factor erythroid 2-related factor 2 (Nrf2) and peroxisome proliferator-activated receptor-β/δ (PPARβ/δ) can be activated to inhibit NF-κB. However, the available data on expression of NF-κB, Nrf2 and PPARβ/δ in CAD patients are limited.

OBJECTIVE

To evaluate the expression of the transcription factors NF-κB and Nrf2 and PPAR𝛽/𝛿 in CAD patients.

METHODS

Thirty-five patients (17 men, mean age 62.4 ? 7.55 years) with CAD and twelve patients (5 men, mean age 63.50 ? 11.46 years) without CAD were enrolled. Peripheral blood mononuclear cells (PBMCs) were isolated and processed for mRNA expression of Nrf2, NF-κB, NADPH: quinone oxidoreductase 1 (NQO1) and PPARβ/δ mRNAs using quantitative real-time polymerase chain reaction (qPCR). p < 0.05 was considered statistically significant.

RESULTS

There was no difference in the mRNA expressions of Nrf2 (1.35 ? 0.57), NF-κB (1.08 ? 0.50) or in the antioxidant enzyme NQO1 (1.05 ? 0.88) in the CAD group compared to the group without CAD (1.16 ? 0.76, 0.95 ? 0.33, 0.81 ? 0.55, respectively). However, PPARβ/δ was highest expressed in the CAD group (1.17 ? 0.86 vs. 0.56 ? 0.34, p = 0.008).

CONCLUSION

The main finding of this study was the PPARβ/δ being more expressed in the PBMC of patients with CAD compared to the control group, whereas no differences were observed in Nrf2 or NF-κB mRNA expressions.

Hydrogen sulfide stabilizes atherosclerotic plaques in apolipoprotein E knockout mice

Hydrogen sulfide gas (H₂S) has protective effects in the cardiovascular system that includes preventing the development of atherosclerosis when tested in several in vivo models. Plaque instability is a major risk factor for thromboembolism, myocardial infarction, and stroke, so we examined if H₂S can promote plaque stability and the potential underlying mechanisms. Apolipoprotein E knockout mice fed an atherogenic diet were administered the exogenous H₂S donor sodium hydrosulfide (NaHS) or pravastatin as a positive control daily for 14 weeks. NaHS significantly enhanced plaque stability by increasing fibrous cap thickness and collagen content compared to vehicle-treated controls. NaHS treatment also reduced blood lipid levels and plaque formation. Preservation of plaque stability by NaHS was associated with reductions in vascular smooth muscle cells (VSMCs) apoptosis and expression of the collagen-degrading enzyme matrix metallopeptidase-9 (MMP-9) in plaque. While pravastatin also increased fibrous cap thickness and reduced VSMC apoptosis, but did not enhance plaque collagen or reduce MMP-9 significantly, suggesting distinct mechanisms of plaque stabilization. in vitro, NaHS also decreased MMP-9 expression in macrophages stimulated with tumor necrosis factor-α by inhibiting ERK/JNK phosphorylation and activator protein 1 nuclear translocation. Moreover, H₂S reduced caspase-3/9 activity, Bax/Bcl-2 ratio, and LOX-1 mRNA expression in VSMCs stimulated with oxidized low-density lipoprotein. These results suggest that H₂S enhances plaque stability and protects against atherogenesis by increasing plaque collagen content and VSMC count. In conclusion, H₂S exerts protective effects against atherogenesis at least partly by stabilizing atherosclerotic plaque.

Pregnancy-associated plasma protein-A promotes TF procoagulant activity in human endothelial cells by Akt-NF-κB axis

Pregnancy-associated plasma protein-A (PAPP-A) is a metalloproteinase with a controversial role in pathophysiology of cardiovascular disease. It seems involved in progression of atherosclerosis and is widely represented in atherosclerotic plaque. PAPP-A plasma levels are elevated in patients with acute coronary syndromes (ACS), thus it has been suggested that it might be a prognostic marker for developing major cardiovascular events. However, the pathophysiological link(s) between PAPP-A and ACS are still unknown. Several studies have indicated that tissue factor (TF) plays a pivotal role in the pathophysiology of ACS by triggering the formation of intracoronary thrombi following endothelial injury. This study investigates whether PAPP-A, at concentrations measurable in ACS patients, might induce TF expression in human endothelial cells in culture (HUVEC). In HUVEC, PAPP-A induced TF-mRNA transcription as demonstrated by real time PCR and expression of functionally active TF as demonstrated by FACS analysis and pro-coagulant activity assay. PAPP-A induced TF expression through the activation of Akt/NF-κB axis, as demonstrated by luciferase assay and by suppression of TF-mRNA transcription as well as of TF expression/activity by Akt and NF-κB inhibitors. These data indicate that PAPP-A promotes TF expression in human endothelial cells and support the hypothesis that this proteinase, besides being involved in progression of atherosclerosis, does not represent an independent risk factor for adverse cardiovascular events, but it rather might play an "active" role in the pathophysiology of ACS as an effector molecule able to induce a pro-thrombotic phenotype in endothelial cells.

Vinexin β Ablation Inhibits Atherosclerosis in Apolipoprotein E-Deficient Mice by Inactivating the Akt-Nuclear Factor κB Inflammatory Axis

Background

Vinexin β is a novel adaptor protein that regulates cellular adhesion, cytoskeletal reorganization, signal transduction, and transcription; however, the exact role that vinexin β plays in atherosclerosis remains unknown.

Methods and Results

Immunoblot analysis showed that vinexin β expression is upregulated in the atherosclerotic lesions of both patients with coronary heart disease and hyperlipemic apolipoprotein E–deficient mice and is primarily localized in macrophages indicated by immunofluorescence staining. The high‐fat diet–induced double‐knockout mice exhibited lower aortic plaque burdens than apolipoprotein E^−/− littermates and decreased macrophage content. Vinexin β deficiency improved plaque stability by attenuating lipid accumulation and increasing smooth muscle cell content and collagen. Moreover, the bone marrow transplant experiment demonstrated that vinexin β deficiency exerts atheroprotective effects in hematopoietic cells. Consistent with these changes, the mRNA expression of proinflammatory cytokines were downregulated in vinexin β^−/− apolipoprotein E^−/− mice, whereas the anti‐inflammatory M2 macrophage markers were upregulated. The immunohistochemical staining and in vitro experiments showed that deficiency of vinexin β inhibited the accumulation of monocytes and the migration of macrophages induced by tumor necrosis factor α–stimulated human umbilical vein endothelial cells as well as macrophage proliferation. Finally, the inhibitory effects exerted by vinexin β deficiency on foam cell formation, nuclear factor κB activation, and inflammatory cytokine expression were largely reversed by constitutive Akt activation, whereas the increased expression of the nuclear factor κB subset promoted by adenoviral vinexin β was dramatically suppressed by inhibition of AKT.

Conclusions

Vinexin β deficiency attenuates atherogenesis primarily by suppressing vascular inflammation and inactivating Akt–nuclear factor κB signaling. Our data suggest that vinexin β could be a therapeutic target for the treatment of atherosclerosis.

Nobiletin inhibits oxidized-LDL mediated expression of Tissue Factor in human endothelial cells through inhibition of NF-κB

INTRODUCTION

Flavonoids are nutrients usually included in human diet with several significant biological activities. Nobiletin is a flavonoid that, besides having anti-inflammatory and anti-tumoral activity, seems to exert protective effects on cardiovascular system. Several studies investigated nobiletin as a natural drug to antagonize the atherosclerotic disease. On the contrary, literature about its potential role in modulating the main acute complication of atherosclerosis, thrombosis, is still scanty. Several studies have indicated that Tissue Factor (TF) plays a pivotal role in the pathophysiology of cardiovascular thrombotic events by triggering the formation of intracoronary thrombi. Oxidized-LDL have an important role in promoting athero-thrombotic events. This study investigates whether nobiletin might exert protective cardiovascular effects by preventing the oxidized-LDL mediated expression of TF in human endothelial cells in vitro. Moreover, we have studied whether the nobiletin effects might be modulated by the inhibition of the NF-κB pathway.

METHODS AND RESULTS

In HUVEC, ox-LDL induced TF-mRNA transcription as demonstrated by real time PCR and expression of functionally active TF as demonstrated by Western-blot, FACS analysis and pro-coagulant activity assay. Nobiletin prevented these ox-LDL-mediated effects by exerting antioxidant effects, finally leading to inhibition of the transcription factor NF-κB.

CONCLUSIONS

These data suggest that nobiletin might be a potential antithrombotic agent of dietary origin. This flavonoid, through its antioxidant proprieties, might potentially exert an antithrombotic activity by inhibiting TF expression/activity in a cell population never investigated before in this context and that is normally represented in vessel wall such as endothelial cells.

Fructose induces prothrombotic phenotype in human endothelial cells : A new role for "added sugar" in cardio-metabolic risk

Intake of large amounts of added sweeteners has been associated with the pathogenesis of cardiometabolic risk. Several studies have shown that fructose increases the cardiovascular risk by modulating endothelial dysfunction and promoting atherosclerosis. Recently, a potential role for fructose in cardiovascular thrombosis has been suggested but with controversial results. Tissue factor (TF) plays a pivotal role in the pathophysiology of cardiovascular thrombosis by triggering the formation of intracoronary thrombi following endothelial injury. This study investigates the effects of fructose, in a concentration range usually observed in the plasma of patients with increased cardiovascular risk, on TF in human umbilical endothelial cells (HUVECs). Cells were stimulated with increasing concentrations of fructose (0.25, 1 and 2.5 mM) and then processed to evaluate TF-mRNA levels by real-time PCR as well as TF expression/activity by FACS analysis and procoagulant activity. Finally, a potential molecular pathway involved in modulating this phenomenon was investigated. We demonstrate that fructose induces transcription of mRNA for TF. In addition, we show that this monosaccharide promotes surface expression of TF that is functionally active. Fructose effects on TF appear modulated by the oxygen free radicals through activation of the transcription factor NF-κB since superoxide dismutase and NF-κB inhibitors suppressed TF expression. Data of the present study, although in vitro, indicate that fructose, besides promoting atherosclerosis, induces a prothrombotic phenotype in HUVECs, thus indicating one the mechanism(s) by which this sweetener might increase cardiometabolic risk.

Tricin, flavonoid from Njavara reduces inflammatory responses in hPBMCs by modulating the p38MAPK and PI3K/Akt pathways and prevents inflammation associated endothelial dysfunction in HUVECs

Previous studies revealed the potent anti-inflammatory activity of tricin, the active component of Njavara rice bran. Here, we report the involvement of specific signaling pathways in the protective effect of tricin against LPS induced inflammation in hPBMCs and the role of tricin in modulating endothelial dysfunction in LPS induced HUVECs. Pretreatment with tricin (15μM) significantly inhibited the release of TNF-α and was comparable to the specific pathway blockers like ERK inhibitor (PD98059), JNK inhibitor (SP600125) and p38 inhibitor (SB203580), whereas an increased release of TNF-α was observed in PI3K/Akt inhibitor (LY294002) treated cells. Tricin alone and combination treatment of tricin and SB203580 showed more significant inhibition of activation of COX-2 and TNF-α than that of SB203580 alone treated group. Combination treatment of tricin and LY294002 showed increased activation of COX-2 and TNF-α, proved that PI3K activation is essential for the anti-inflammatory effect of tricin. Studies conducted on HUVECs revealed the protective effect of tricin against endothelial dysfunction associated with LPS induced inflammation by inhibiting the activation of proinflammatory mediators like TNF-α, IFN-γ, MCP 1 by modulating NF-κB and MAPK signaling pathways. ELISA and flow cytometric analysis again confirmed the protection of tricin against endothelial damage, especially from the decreased activation of cell adhesion molecules like ICAM-1, VCAM-1 and E-Selectin upon tricin treatment. This work establishes the mechanism behind the potent anti-inflammatory activity of the flavonoid tricin.

Small-nucleic-acid-based therapeutic strategy targeting the transcription factors regulating the vascular inflammation, remodeling and fibrosis in atherosclerosis

Atherosclerosis arises when injury to the arterial wall induces an inflammatory cascade that is sustained by a complex network of cytokines, together with accumulation of lipids and fibrous material. Inflammatory cascades involve leukocyte adherence and chemotaxis, which are coordinated by the local secretion of adhesion molecules, chemotactic factors, and cytokines. Transcription factors are critical to the integration of the various steps of the cascade response to mediators of vascular injury, and are induced in a stimulus-dependent and cell-type-specific manner. Several small-nucleic-acid-based therapeutic strategies have recently been developed to target transcription factors: antisense oligodeoxynucleotides, RNA interference, microRNA, and decoy oligodeoxynucleotides. The aim of this review was to provide an overview of these particular targeted therapeutic strategies, toward regulation of the vascular inflammation, remodeling and fibrosis associated with atherosclerosis.

Vascular wall hypoxia promotes arterial thrombus formation via augmentation of vascular thrombogenicity

Atherosclerotic lesions represent a hypoxic milieu. However, the significance of this milieu in atherothrombosis has not been established. We aimed to assess the hypothesis that vascular wall hypoxia promotes arterial thrombus formation. We examined the relation between vascular wall hypoxia and arterial thrombus formation using a rabbit model in which arterial thrombosis was induced by 0.5 %-cholesterol diet and repeated balloon injury of femoral arteries. Vascular wall hypoxia was immunohistochemically detected by pimonidazole hydrochloride, a hypoxia marker. Rabbit neointima and THP-1 macrophages were cultured to analyse prothrombotic factor expression under hypoxic conditions (1 % O2). Prothrombotic factor expression and nuclear localisation of hypoxia-inducible factor (HIF)-1α and nuclear factor-kappa B (NF-κB) p65 were immunohistochemically assessed using human coronary atherectomy plaques. Hypoxic areas were localised in the macrophage-rich deep portion of rabbit neointima and positively correlated with the number of nuclei immunopositive for HIF-1α and NF-κB p65, and tissue factor (TF) expression. Immunopositive areas for glycoprotein IIb/IIIa and fibrin in thrombi were significantly correlated with hypoxic areas in arteries. TF and plasminogen activator inhibitor-1 (PAI-1) expression was increased in neointimal tissues and/or macrophages cultured under hypoxia, and both were suppressed by inhibitors of either HIF-1 or NF-κB. In human coronary plaques, the number of HIF-1α-immunopositive nuclei was positively correlated with that of NF-κB-immunopositive nuclei and TF-immunopositive and PAI-1-immunopositive area, and it was significantly higher in thrombotic plaques. Vascular wall hypoxia augments the thrombogenic potential of atherosclerotic plaque and thrombus formation on plaques via prothrombotic factor upregulation.

The adipokine apelin-13 induces expression of prothrombotic tissue factor

Adipocytes are cells able to produce and secrete several active substances (adipokines) with direct effects on vascular cells. Apelin, one of the most recently identified adipokines has been studied in cardiovascular system physiology in regard to vessel vasodilation and myocardial contraction, but it has not yet completely characterised for its pathophysiological role in cardiovascular disease and especially in acute coronary syndromes (ACS). Several studies have indicated that tissue factor (TF) plays a pivotal role in the pathophysiology of ACS by triggering the formation of intracoronary thrombi following endothelial injury. This study investigates the effects of apelin 12 and apelin 13 on TF in human umbilical endothelial cells (HUVECs) and monocytes. Cells were stimulated with increasing concentrations of apelin 12 or apelin 13 and then processed to evaluate TF-mRNA levels by real-time PCR as well as TF expression/activity by FACS analysis and pro-coagulant activity. Finally, a potential molecular pathway involved in modulating this phenomenon was investigated. We demonstrate that apelin 13 but not apelin 12 induces transcription of mRNA for TF. In addition, we show that this adipokine promotes surface expression of TF that is functionally active. Apelin 13 effects on TF appear modulated by the activation of the G-protein-transcription factor nuclear factor (NF)-κB axis since G-protein inhibitors suppressed NF-κB mediated TF expression. Data of the present study, although in vitro, indicate that apelin-13, induces a procoagulant phenotype in HUVECs and monocytes by promoting TF expression. These observations support the hypothesis that this adipokine might play a relevant role as an active partaker in athero-thrombotic disease.

A potential therapeutic effect of CYP2C8 overexpression on anti-TNF-α activity

Epoxyeicosatrienoic acids (EETs) are generated from arachidonic acid catalysed by cytochrome P450 (CYP) epoxygenases. In addition to regulating vascular tone EETs may alleviate inflammation and ROS. The present study was conducted to determine whether CYP2C8 gene overexpression was able to increase the level of EETs, and subsequently prevent TNF-α induced inflammation and reactive oxygen species (ROS) in human umbilical vein endothelial cells (HUVECs) and macrophages. Peroxisome proliferator-activated receptor γ (PPARγ) activation, nuclear factor-κB (NF-κB) activation, endothelial nitric oxide synthase (eNOS) activation, gp-91 activation, and inflammatory cytokine expression were detected by western blot analysis or enzyme-linked immunosorbent assay. Intracellular reactive oxygen species (ROS) was measured by flow cytometry, while the migration of vascular smooth muscle cells (VSMCs) was detected by Transwell assay. pCMV-mediated CYP2C8 overexpression and its metabolites, EETs, markedly suppressed TNF-α induced inflammatory cytokines IL-6 and MCP-1 expression via the activation of NF-κB and degradation of IκBα. Moreover, pretreatment with 11,12-EET significantly blocked TNF-α-induced ROS production. CYP2C8-derived EETs also effectively alleviated the migration of VSMCs and improved the function of endothelial cells through the upregulation of eNOS, which was significantly decreased under the stimulation of TNF-α. Furthermore, these protective effects observed were mediated by PPARγ activation. To the best of our knowledge, the results of the present study demonstrated for the first time that CYP2C8-derived EETs exerted antivascular inflammatory and anti-oxidative effects, at least in part, through the activation of PPARγ. Thus, the CYP2C8 gene may be useful in the prevention and treatment of vascular inflammatory diseases.

Bone marrow-specific knock-in of a non-activatable Ikkα kinase mutant influences haematopoiesis but not atherosclerosis in Apoe-deficient mice

Background

The Ikkα kinase, a subunit of the NF-κB-activating IKK complex, has emerged as an important regulator of inflammatory gene expression. However, the role of Ikkα-mediated phosphorylation in haematopoiesis and atherogenesis remains unexplored. In this study, we investigated the effect of a bone marrow (BM)-specific activation-resistant Ikkα mutant knock-in on haematopoiesis and atherosclerosis in mice.

Methods and Results

Apolipoprotein E (Apoe)-deficient mice were transplanted with BM carrying an activation-resistant Ikkα gene (Ikkα^AA/AAApoe^−/−) or with Ikkα^+/+Apoe^−/− BM as control and were fed a high-cholesterol diet for 8 or 13 weeks. Interestingly, haematopoietic profiling by flow cytometry revealed a significant decrease in B-cells, regulatory T-cells and effector memory T-cells in Ikkα^AA/AAApoe^−/− BM-chimeras, whereas the naive T-cell population was increased. Surprisingly, no differences were observed in the size, stage or cellular composition of atherosclerotic lesions in the aorta and aortic root of Ikkα^AA/AAApoe^−/− vs Ikkα^+/+Apoe^−/− BM-transplanted mice, as shown by histological and immunofluorescent stainings. Necrotic core sizes, apoptosis, and intracellular lipid deposits in aortic root lesions were unaltered. In vitro, BM-derived macrophages from Ikkα^AA/AAApoe^−/− vs Ikkα^+/+Apoe^−/− mice did not show significant differences in the uptake of oxidized low-density lipoproteins (oxLDL), and, with the exception of Il-12, the secretion of inflammatory proteins in conditions of Tnf-α or oxLDL stimulation was not significantly altered. Furthermore, serum levels of inflammatory proteins as measured with a cytokine bead array were comparable.

Conclusion

Our data reveal an important and previously unrecognized role of haematopoietic Ikkα kinase activation in the homeostasis of B-cells and regulatory T-cells. However, transplantation of Ikkα^AA mutant BM did not affect atherosclerosis in Apoe^−/− mice. This suggests that the diverse functions of Ikkα in haematopoietic cells may counterbalance each other or may not be strong enough to influence atherogenesis, and reveals that targeting haematopoietic Ikkα kinase activity alone does not represent a therapeutic approach.

Nuclear factor κ-B is activated in the pulmonary vessels of patients with end-stage idiopathic pulmonary arterial hypertension

OBJECTIVES

To assess activation of the inflammatory transcription factor NF-kappa B (NF-κB) in human idiopathic pulmonary arterial hypertension (PAH).

BACKGROUND

Idiopathic PAH is a severe progressive disease characterized by pulmonary vascular remodeling and excessive proliferation of vascular cells. Increasing evidence indicates that inflammation is important in disease pathophysiology.

METHODS

NF-κB-p65 and CD68, CD20 and CD45 were measured by immunohistochemistry and confocal microscopy on lung specimens from patients with idiopathic PAH (n = 12) and controls undergoing lung surgery (n = 14). Clinical data were recorded for all patients including invasive pulmonary hemodynamics for the PAH patients. Immunohistochemical images were analyzed by blinded observers to include standard pulmonary vascular morphometry; absolute macrophage counts/mm(2) and p65-positivity (p65+) using composite images and image-analysis software; and cytoplasmic:nuclear p65+ of individual pulmonary arterial endothelial and smooth muscle cells (PASMC) in 10-20 pulmonary arteries or arterioles per subject. The expression of ET-1 and CCL5 (RANTES) in whole lung was determined by RT-qPCR.

RESULTS

Macrophage numbers were increased in idiopathic PAH versus controls (49.0±4.5 vs. 7.95±1.9 macrophages/100 mm(2), p<0.0001): these macrophages demonstrated more nuclear p65+ than in macrophages from controls (16.9±2.49 vs. 3.5±1.25%, p<0.001). An increase in p65+ was also seen in perivascular lymphocytes in patients with PAH. Furthermore, NF-κB activation was increased in pulmonary arterial endothelial cells (62.3±2.9 vs. 14.4±3.8, p<0.0001) and PASMC (22.6±2.3 vs. 11.2±2.0, p<0.001) in patients with PAH versus controls, with similar findings in arterioles. Gene expression of both ET-1 mRNA ((0.213±0.069 vs. 1.06±0.23, p<0.01) and CCL5 (RANTES) (0.16±0.045 vs. 0.26±0.039, p<0.05) was increased in whole lung homogenates from patients with PAH.

CONCLUSIONS

NF-κB is activated in pulmonary macrophages, lymphocytes, endothelial and PASMC in patients with end-stage idiopathic PAH. Future research should determine whether NF-κB activation is a driver or bystander of pulmonary vascular inflammation and if the former, its potential role as a therapeutic target.

The efficacy of edaravone (radicut), a free radical scavenger, for cardiovascular disease

Edaravone was originally developed as a potent free radical scavenger, and has been widely used to treat acute ischemic stroke in Japan since 2001. Free radicals play an important role in the pathogenesis of a variety of diseases, such as cardiovascular diseases and stroke. Therefore, free radicals may be targets for therapeutic intervention in these diseases. Edaravone shows protective effects on ischemic insults and inflammation in the heart, vessel, and brain in experimental studies. As well as scavenging free radicals, edaravone has anti-apoptotic, anti-necrotic, and anti-cytokine effects in cardiovascular diseases and stroke. Edaravone has preventive effects on myocardial injury following ischemia and reperfusion in patients with acute myocardial infarction. Edaravone may represent a new therapeutic intervention for endothelial dysfunction in the setting of atherosclerosis, heart failure, diabetes, or hypertension, because these diseases result from oxidative stress and/or cytokine-induced apoptosis. This review evaluates the potential of edaravone for treatment of cardiovascular disease, and covers clinical and experimental studies conducted between 1984 and 2013. We propose that edaravone, which scavenges free radicals, may offer a novel option for treatment of cardiovascular diseases. However, additional clinical studies are necessary to verify the efficacy of edaravone.

Peptide inhibitor of NF-κB translocation ameliorates experimental atherosclerosis

Atherosclerosis is a chronic inflammatory disease of the arterial wall. NF-κB is a major regulator of inflammation that controls the expression of many genes involved in atherogenesis. Activated NF-κB was detected in human atherosclerotic plaques, and modulation of NF-κB inflammatory activity limits disease progression in mice. Herein, we investigate the anti-inflammatory and atheroprotective effects of a cell-permeable peptide containing the NF-κB nuclear localization sequence (NLS). In vascular smooth muscle cells and macrophages, NLS peptide specifically blocked the importin α-mediated nuclear import of NF-κB and prevented lipopolysaccharide-induced pro-inflammatory gene expression, cell migration, and oxidative stress. In experimental atherosclerosis (apolipoprotein E-knockout mice fed a high-fat diet), i.p., 0.13 μmol/day NLS peptide administration for 5 weeks attenuated NF-κB activation in atherosclerotic plaques. NLS peptide significantly inhibited lesion development at both early (age 10 weeks) and advanced (age 28 weeks) stages of atherosclerosis in mice, without affecting serum lipid levels. Plaques from NLS-treated mice contained fewer macrophages of pro-inflammatory M1 subtype than those from respective untreated controls. By contrast, the relative smooth muscle cell and collagen content was increased, indicating a more stable plaque phenotype. NLS peptide also attenuated pro-inflammatory gene expression and oxidative stress in aortic lesions. Our study demonstrates that targeting NF-κB nuclear translocation hampers inflammation and atherosclerosis development and identifies cell-permeable NLS peptide as a potential anti-atherosclerotic agent.

Inflammatory cytokines promote mesenchymal transformation in embryonic and adult valve endothelial cells

OBJECTIVE

Inflammatory activation of valve endothelium is an early phase of aortic valve disease pathogenesis, but subsequent mechanisms are poorly understood. Adult valve endothelial cells retain the developmental ability to undergo endothelial-to-mesenchymal transformation (EndMT), but a biological role has not been established. Here, we test whether and how inflammatory cytokines (tumor necrosis factor-α and interleukin-6) regulate EndMT in embryonic and adult valve endothelium.

METHODS AND RESULTS

Using in vitro 3-dimensional collagen gel culture assays with primary cells, we determined that interleukin-6 and tumor necrosis factor-α induce EndMT and cell invasion in dose-dependent manners. Inflammatory-EndMT occurred through an Akt/nuclear factor-κB-dependent pathway in both adult and embryonic stages. In embryonic valves, inflammatory-EndMT required canonical transforming growth factor-β signaling through activin receptor-like kinases 2 and 5 to drive EndMT. In adult valve endothelium, however, inflammatory-induced EndMT still occurred when activin receptor-like kinases 2 and 5 signaling was blocked. Inflammatory receptor gene expression was significantly upregulated in vivo during embryonic valve maturation. Endothelial-derived mesenchymal cells expressing activated nuclear factor-κB were found distal to calcific lesions in diseased human aortic valves.

CONCLUSIONS

Inflammatory cytokine-induced EndMT in valve endothelium is present in both embryonic and adult stages, acting through Akt/nuclear factor-κB, but differently using transforming growth factor-β signaling. Molecular signatures of valve EndMT may be important diagnostic and therapeutic targets in early valve disease.

Suppression of oxLDL-induced MMP-9 and EMMPRIN expression by berberine via inhibition of NF-κB activation in human THP-1 macrophages

Upregulation of matrix metalloproteinases (MMPs) and extracellular matrix metalloproteinase inducer (EMMPRIN) by macrophages leads to atherosclerotic plaque rupture by degradation of the extracellular matrix. NF-κB activation regulates many key inflammatory genes linked to atherosclerosis. In the present study, the function of berberine, a natural extract from Rhizoma coptidis, on MMP-9 and EMMPRIN expression, the role of NF-κB activation in oxLDL-stimulated macrophages, and the possible mechanism in which NF-κB activation is involved were investigated. Berberine inhibited the expression of MMP-9 and EMMPRIN at both mRNA and protein levels. The phosphorylation of IκB-α and nuclear translocation of p65 protein were reduced by berberine, suggesting that NF-κB activation was inhibited by berberine in oxLDL-stimulated macrophages. Overall, berberine suppressed the expression of MMP-9 and EMMPRIN by at least reducing partly the activity of NF-κB in oxLDL-induced macrophages.

Effects of tumour necrosis factor-alpha on activity and nitric oxide synthase of endothelial progenitor cells from peripheral blood

The aim of this investigation was to determine whether tumour necrosis factor-alpha (TNF-α) has any effect on endothelial progenitor cells (EPCs). Total mononuclear cells were isolated from peripheral blood by Ficoll density gradient centrifugation, and then the cells were plated on fibronectin-coated culture dishes. After 7 days culture, attached cells were stimulated with tumour necrosis factor-α (final concentrations: 0, 10, 20, 50 and 100 mg/l) for 0, 6, 12, 24 and 48 h. EPCs were characterized as adherent cells double positive for DiLDL-uptake and lectin binding, by direct fluorescence staining. EPC proliferation and migration were assayed using the MTT assay and modified Boyden chamber assay, respectively. EPC adhesion assay was performed by re-plating those cells on fibronectin-coated dishes, and adherent cells were counted. Tube formation activity was assayed using a tube formation kit. Levels of apoptosis were revealed using an annexin V apoptosis detection kit. Vascular endothelial growth factor Receptor-1 (VEGF-R1) and stromal derived factor-1 (SDF-1) mRNA, assessed by real-time RT-PCR inducible nitric oxide synthase (iNOS) and endothelial nitric oxide synthase (eNOS) were assayed by western blot analysis. Incubation of EPCs with tumour necrosis factor-α reduced EPC proliferation, migration, adhesion, tube formation capacity, iNOS and eNOS in concentration- and time-dependent manners. Tumour necrosis factor-α reduced proliferation, migration, adhesion and tube formation capacity of EPCs. TNF-α increased EPC apoptosis level, reduced VEGF-R1 and SDF-1 mRNA expression; tumour necrosis factor-α also reduced iNOS and eNOS in the EPCs.

-94 ins/del ATTG NFKB1 gene variant is associated with lower susceptibility to myocardial infarction

BACKGROUND AND AIMS

An imbalance of Nuclear Factor Kappa B (NFкB) and Inhibitor Kappa B (IкB) is involved in various human diseases including atherogenesis. We aimed to evaluate the relationship between NFKB1 and NFKBIA polymorphism and susceptibility to myocardial infarction (MI).

METHODS AND RESULTS

Genotyping was performed for NFKB1 and NFKBIA gene variants in 253 subjects (86 patients affected by myocardial infarction and 167 control subjects). In 40 patients, biopsy specimens were taken from the left ventricle area of presumed ischemia for p50, p65 and IкBα quantification. The allele frequency and genotype distribution of NFKBIA gene polymorphism did not differ between MI and control group while control subjects had a higher D allele frequency of -94 ins/del ATTG NFKB1 polymorphism, compared to the MI group (P<0.001; OR=0.304; 95% CI=0.177-0.522). Subjects carrying the D allele had significantly lower plasma fibrinogen and CRP (C-reactive protein) levels compared to no carriers (P<0.05). Fibrinogen-genotype interaction was found to have a significant effect on susceptibility to myocardial infarction. Myocardial p50 (r=0.627; P=0.012) and p65 (r=0.683; P=0.005) levels significantly correlated with plasma fibrinogen levels while subjects carrying the D allele of the NFкB1 gene variant had lower myocardial p50 (P=0.007) and p65 (P=0.009) levels compared to no carriers.

CONCLUSION

-94 ins/del ATTG NFKB1 gene variant may contribute to lower MI susceptibility via the potential reduction of activated NFкB which in turn is related to plasma inflammatory marker reduction.

Aronia melanocarpa fruit extract exhibits anti-inflammatory activity in human aortic endothelial cells

Background

Altered expression of cell adhesion molecules (CAMs) has been implicated in a variety of chronic inflammatory conditions, including atherosclerosis. Regulation of adhesion molecule expression by specific redox-sensitive mechanisms has been reported. Additionally, it has been observed that the extract of Aronia melanocarpa (A. Melanocarpa) fruits, rich in polyphenols, exhibits potent anti-oxidant properties and displays cardioprotective activity.

Methods and results

Human aortic endothelial cells (HAECs) were pretreated with various concentrations (primarily 50 μg/mL) of Aronia Melanocarpa fruit extract prior to treatment with TNFα (10 ng/mL) for various periods of time. The surface protein and mRNA expression of ICAM-1 and VCAM-1 were determined using flow cytometry and real-time RT-PCR, respectively. Adhesion of peripheral blood mononuclear leucocytes (PBMLs) to TNFα-treated HAECs was evaluated by an adhesion assay. Activation of NF-κB was evaluated by measuring NF-κB p65 phosphorylation using flow cytometry. ROS production was determined by reduction in fluorescent 2′,7′-dichlorofluorescein diacetate (DCFH-DA). Tested A. Melanocarpa extract significantly inhibited the expression of ICAM-1 and VCAM-1, attenuated the phosphorylation of NF-κB p65 and decreased intracellular ROS production in TNFα-treated HAECs.

Conclusion

We conclude that A. Melanocarpa fruit extract exhibits anti-inflammatory effects in HAECs by inhibiting the expression of endothelial CAMs, activation of NF-κB and production of ROS.

Oxidative stress as a mediator of cardiovascular disease

During physiological processes molecules undergo chemical changes involving reducing and oxidizing reactions. A molecule with an unpaired electron can combine with a molecule capable of donating an electron. The donation of an electron is termed as oxidation whereas the gaining of an electron is called reduction. Reduction and oxidation can render the reduced molecule unstable and make it free to react with other molecules to cause damage to cellular and sub-cellular components such as membranes, proteins and DNA. In this paper, we have discussed the formation of reactive oxidant species originating from a variety of sources such as nitric oxide (NO) synthase (NOS), xanthine oxidases (XO), the cyclooxygenases, nicotinamide adenine dinucleotide phosphate (NAD(P)H) oxidase isoforms and metal-catalysed reactions. In addition, we present a treatise on the physiological defences such as specialized enzymes and antioxidants that maintain reduction-oxidation (redox) balance. We have also given an account of how enzymes and antioxidants can be exhausted by the excessive production of reactive oxidant species (ROS) resulting in oxidative stress/nitrosative stress, a process that is an important mediator of cell damage. Important aspects of redox imbalance that triggers the activity of a number of signalling pathways including transcription factors activity, a process that is ubiquitous in cardiovascular disease related to ischemia/reperfusion injury have also been presented.

Overexpression of activated nuclear factor-kappa B in aorta of patients with coronary atherosclerosis

BACKGROUND

Inflammation is an established risk factor for atherosclerosis. In an inflammatory state, nuclear factor-kappa B (NF-kappaB) is frequently activated as a key transcription activator for the downstream responses.

HYPOTHESIS

The aim of this study was to investigate the changes of NF-kappaB in the aorta of patients with coronary atherosclerosis and its association with atherosclerotic risk factors.

METHODS

From 2004 to 2005, we collected a small piece of ascending aorta in the bypass procedure from patients (n = 31) undergoing coronary artery bypass graft (CABG) surgery. The expression of NF-kappaB was determined by immunohistochemistry, and its transcriptional activity was evaluated by electrophoretic mobility shift assay. Celiac aortic tissues from 4 subjects without known atherosclerosis through the kidney donation program were taken as control.

RESULTS

NF-kappaB was detectable in aortas from CABG patients with the transcriptional activities significantly increased. The relative level of aortic NF-kappaB expression was elevated in patients who were smokers or with hypertension. Spearman correlation revealed that aortic NF-kappaB expression had significant correlation with coronary severity scores (Gensini score, r = 0.608, P < .05). The NF-kappaB expression was positively correlated with the levels of blood glucose, low-density lipoprotein cholesterol, lipoprotein(a), total cholesterol, and non-high-density lipoprotein cholesterol (P < .05); but negatively correlated with high-density lipoprotein cholesterol (P < .05).

CONCLUSIONS

Our study demonstrates a highly activated NF-kappaB in aortas from patients with coronary atherosclerosis, which may reflect overall arterial overinflammatory status. The findings of hyperactive NF-kappaB in aortas may provide a diagnostic parameter for the inflammation that is associated with and may cause atherosclerosis.

Enhanced TLR4 endothelial cell immunohistochemical expression in symptomatic carotid atherosclerotic plaques

BACKGROUND AND PURPOSE

Toll-like receptor-4 (TLR4) has been linked to the pathogenesis of atherosclerosis. Carotid atheroma endothelial cells (ECs) express TLR4, nevertheless correlations with cerebrovascular symptomatology, epidemiological and clinical variables remain unresolved.

METHODS

Carotid atherosclerotic plaques were obtained by standard carotid endarterectomy from 157 patients with carotid artery disease (84 asymptomatic - Group A, 73 symptomatic - Group B). TLR4 expression was detected by immunohistochemistry and TLR4 positivity, overexpression and intensity of immunostaining in ECs were correlated with cerebrovascular symptomatology, epidemiological and clinical variables.

RESULTS

A significant association was found between TLR4 positivity in ECs and the occurrence of any cerebrovascular event (overall response (OR): 2.85, 95% CI 1.33 - 6.11, p = 0.009). TLR4 overexpression and staining intensity in ECs were both significantly enhanced in symptomatic patients (p < 0.0001 and p = 0.003, respectively). These associations were stronger for the occurrence of a major cerebrovascular accident (CVA) compared with a transient ischemic attack (TIA) or amaurosis fugax. TLR4 expression in ECs was less prominent in statin users (OR: 0.25, 95%CI 0.1 - 0.58, p = 0.001], while it was enhanced in restenotic plaques compared with primary atherosclerotic lesions (p = 0.012).

CONCLUSIONS

TLR4 expression in ECs of carotid atheroma was enhanced in symptomatic patients with most commonly 'unstable' - 'more prone to rupture' carotid plaques.

Dual Role of Oxidized LDL on the NF-KappaB Signaling Pathway

Atherosclerosis is a slowly evolutive age-linked disease of large arteries, characterized by a local lipid deposition associated with a chronic inflammatory response, leading potentially to acute plaque rupture, thrombosis and ischemic heart disease. Atherogenesis is a complex sequence of events associating first expression of adhesion molecules, recruitment of mononuclear cells to the endothelium, local activation of leukocytes and inflammation, lipid accumulation and foam cell formation. Low density lipoproteins (LDLs) become atherogenic after undergoing oxidation by vascular cells, that transform them into highly bioreactive oxidized LDL (oxidized LDLs). Oxidized LDLs are involved in foam cell formation, and trigger proatherogenic events such as overexpression of adhesion molecules, chemoattractant agents growth factors and cytokines involved in the inflammatory process, cell proliferation and apoptosis. Moreover, this toxic effect of oxidized LDLs plays probably a role in plaque erosion/rupture and subsequent atherothrombosis. Several biological effects of oxidized LDLs are mediated through changes in the activity of transcription factors and subsequently in gene expression. Oxidized LDLs exert a biphasic effect on the redox-sensitive transcription factor NF-kappaB, which can be activated thereby up-regulating proinflammatory gene expression, such as adhesion molecules, tissue factor, scavenger receptor LOX-1. On the other hand, higher concentrations of oxidized LDLs may inhibit NF-kappaB activation triggered by inflammatory agents such as LPS, and may thereby exert an immunosuppressive effect. This review is an attempt to clarify the mechanism by which oxidized LDLs may up- or down-regulate NF-kappaB, the role of NF-kappaB activation (or inhibition), and the consequences of the oxidized LDLs-mediated NF-kappaB dysregulation and their potential involvement in atherosclerosis.

Endothelial cell-specific NF-kappaB inhibition protects mice from atherosclerosis

Atherosclerosis is a progressive disorder of the arterial wall and the underlying cause of cardiovascular diseases such as heart attack and stroke. Today, atherosclerosis is recognized as a complex disease with a strong inflammatory component. The nuclear factor-kappaB (NF-kappaB) signaling pathway regulates inflammatory responses and has been implicated in atherosclerosis. Here, we addressed the function of NF-kappaB signaling in vascular endothelial cells in the pathogenesis of atherosclerosis in vivo. Endothelium-restricted inhibition of NF-kappaB activation, achieved by ablation of NEMO/IKKgamma or expression of dominant-negative IkappaBalpha specifically in endothelial cells, resulted in strongly reduced atherosclerotic plaque formation in ApoE(-/-) mice fed with a cholesterol-rich diet. Inhibition of NF-kappaB abrogated adhesion molecule induction in endothelial cells, impaired macrophage recruitment to atherosclerotic plaques, and reduced expression of cytokines and chemokines in the aorta. Thus, endothelial NF-kappaB signaling orchestrates proinflammatory gene expression at the arterial wall and promotes the pathogenesis of atherosclerosis.

Effect of intensive atorvastatin therapy on prostaglandin E2 levels and metalloproteinase-9 activity in the plasma of patients with non-ST-elevation acute coronary syndrome

Inflammation plays a pivotal role in the pathophysiology of non-ST elevation acute coronary syndromes (NSTEACS). Intensive statin therapy reduces the recurrence of cardiovascular events after acute coronary syndromes. The aim of this study was to examine nuclear factor-kappa B activity in peripheral blood mononuclear cells, prostaglandin E2 (PGE2) and leukotriene B4 levels, and matrix metalloproteinase-9 (MMP-9) activity in plasma from patients with NSTEACS (at 0 days, 4 days, 2 months, and 6 months), patients with stable coronary artery disease, and healthy controls. On day 4, patients with NSTEACS were randomized to receive atorvastatin 80 mg/day (n = 14) or standard treatment (n = 16) during 2 months to study its effect on these parameters. Nuclear factor-kappa B activity (by electrophoretic mobility shift assay), PGE2 levels (by enzyme-linked immunosorbent assay), and MMP-9 activity (by gelatin zymography) in the plasma of patients with NSTEACS were significantly increased compared with patients with coronary artery disease and healthy controls. At 6 months, MMP-9 activity was normalized, whereas nuclear factor-kappa B activity and PGE2 levels were still increased. Leukotriene B4 plasma levels (by enzyme-linked immunosorbent assay) were similar in patients with NSTEACS and those with coronary artery disease but were significantly higher than those of healthy subjects. There was a significant correlation between plasma PGE2 levels and MMP-9 activity in patients with NSTEACS (r = 0.754, p <0.01). Atorvastatin 80 mg/day reduced circulating PGE2 levels (median 222.4 [interquartile range 157.4 to 253.5] vs 550.8 [276.9 to 613.0] pg/ml, p = 0.006) and MMP-9 activity (0.0025 [0.0017 to 0.0035] vs 0.0280 [0.0057 to 0.0712] arbitrary units, p = 0.03). In conclusion, nuclear factor-kappa B activity in peripheral blood mononuclear cells, and plasma PGE2 levels and MMP-9 activity, increase during NSTEACS. Atorvastatin 80 mg/day normalizes PGE2 levels and MMP-9 activity, providing additional mechanisms by which intensive atorvastatin therapy may reduce the incidence of cardiovascular events.

Human urotensin II induces tissue factor and cellular adhesion molecules expression in human coronary endothelial cells: an emerging role for urotensin II in cardiovascular disease

BACKGROUND

Human urotensin II is an 11-aminoacid peptide with a controversial role in the human cardiovascular system. Indeed, urotensin effects on vascular reactivity and in heart failure are well documented, while its potential role in the pathophysiology of athero-thrombosis is still unknown. This study investigates the effects of urotensin on tissue factor (TF) and VCAM-1/ICAM-1 expression in human coronary endothelial cells (HCAECs).

METHODS AND RESULTS

Urotensin induced TF-mRNA transcription as demonstrated by real time PCR and expression of TF that was functionally active as demonstrated by procoagulant activity assay. In addition, urotensin induced expression of VCAM-1 and ICAM-1 as demonstrated by FACS analysis. VCAM-1 and ICAM-1 were functionally active because they increased leukocyte adhesivity to HCAECs. Urotensin-induced expression of TF and of VCAM-1/ICAM-1 was mediated through the Rho A-activation of the transcription factor, NF-kappaB, as demonstrated by EMSA. Indeed, lovastatin, an HMG-CoA reductase inhibitor, by modulating the Rho activation, and NF-kappaB inhibitors, suppressed the urotensin effects on TF and CAMs.

CONCLUSIONS

Data of the present study, although in vitro, describe the close relationship existing between urotensin II and athero-thrombosis, providing for the first time support for the view that this peptide might have not only vasoactive functions but it might be an effector molecule able to induce a pro-atherothrombotic phenotype in cells of the coronary circulation. Although future studies are required to clarify whether these mechanisms are also important in the clinical setting, this report supports an emerging new role for urotensin II in the pathogenesis and progression of cardiovascular disease.

Possible role of NFkappaB in the embryonic vascular remodeling and the endothelial mesenchymal transition process

The NFkappaB family of transcription factors, particularly the activated p50/p65 heterodimer, is expressed in vascular cells during intimal thickening formation when hemodynamic conditions are altered. Here, we report that p50, p65, IkappaBalpha and IKKalpha display different spatial and temporal patterns of expression and distribution during both chicken embryo aortic wall remodeling and intimal thickening development. Additionally, we show that both p50 and p65 were located in the nucleus of some mesenchymal cells expressing alpha-smooth muscle actin which are present in the spontaneous intimal thickening observed at embryonic days 12-14 of development. We also demonstrated that both NFkappaB subunits are present in monolayers of primary embryonic aortic endothelial cells attached to fibronectin and stimulated with complete medium. This study demonstrates for the first time the presence of activated NFkappaB during the remodeling of the embryonic aortic wall and the formation of intimal thickening, providing evidence that suggest a possible role for this transcription factor in the EndoMT process.

HMG-CoA Reductase Inhibitors Reduce Nicotine-Induced Expression of Cellular Adhesion Molecules in Cultured Human Coronary Endothelial Cells

BACKGROUND

Smoking predisposes to the development of atherosclerosis and of its complications. The mechanisms responsible for these effects are not completely understood. We have investigated whether nicotine might promote a proatherosclerotic state in human coronary endothelial cells (HCAECs), studying the role of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors in preventing these phenomena.

METHODS AND RESULTS

Real-time PCR showed that nicotine induced a dose-dependent increase in mRNA levels for vascular cellular adhesion molecule-1 (VCAM-1)/intercellular adhesion molecule-1 (ICAM-1). Fluorescent-activated cell sorting analysis showed that nicotine induced expression of functionally active VCAM-1/ICAM-1, since they increased leukocyte adherence to HCAECs. Oxygen free radicals, Rho A and nuclear factor kappaB (NF-kappaB) play a pivotal role in modulating these effects. Indeed, nicotine caused oxygen free radical production as well as activation of Rho A and NF-kappaB pathways, evaluated by malondialdehyde levels, pulldown assay and by electrophoretic mobility shift assay, respectively. Superoxide dimutase, Rho A (Y-27639) and NF-kappaB inhibitors (pyrrolidine dithiocarbamate ammonium, Bay 11-7082) suppressed nicotine effects on CAM expression. HMG-CoA reductase inhibitors prevented these nicotine-mediated effects by inhibiting free radical generation and by modulating activation of Rho A and NF-kappaB pathways.

CONCLUSIONS

Nicotine promotes CAM expression on HCAECs, shifting them toward a proatherosclerotic state. These effects might explain, at least in part, the deleterious cardiovascular consequences of cigarette smoking. HMG-CoA reductase inhibitors play an important role in preventing these phenomena.

Secretory products from human adipocytes impair endothelial function via nuclear factor kappaB

Hyperplasia and hypertrophy of fat cells can be found in obesity, and increased adiposity is associated with endothelial dysfunction as an early event of atherosclerosis. However, it is unclear whether human adipocytes directly influence endothelial function. To study the crosstalk between fat and endothelial cells, human umbilical venous endothelial cells (HUVECs), and human coronary artery endothelial cells (HCAECs) were cultured in infranatants (Adipo) of primary differentiated human adipocytes. Interestingly, incubation of HUVECs and HCAECs with Adipo significantly increased monocyte adhesion 7.3 and 2.2-fold, respectively. VCAM-1, ICAM-1, and E-selectin in HUVECs were upregulated 3.9, 3.0, and 9.5-fold, respectively, under these conditions. Furthermore, Adipo significantly stimulated NFkappaB activity 1.9-fold. The NFkappaB inhibitor MG-132 and heat inactivation significantly reversed Adipo-stimulated monocyte adhesion. TNFalpha-neutralizing antibodies partly reversed Adipo-induced monocyte adhesion. In contrast, thiazolidinedione-pretreatment of human adipocytes did not alter the effects of Adipo. Adipo did not show cytotoxic effects. Taken together, we demonstrate that endothelial dysfunction is induced by adipocyte-secreted factors via NFkappaB partly dependent on TNFalpha.

Circulating human monocytes in the acute coronary syndrome express a characteristic proteomic profile

We examined the proteome of circulating monocytes of patients with acute coronary syndrome at different times in comparison to that of patients with stable coronary artery disease. On admission, the expression of 18 spot proteins was altered, 10 of which were totally absent. This pattern changed progressively, and at 6 months, there were no differences with the monocyte proteome of stable patients.

Persistent activation of nuclear factor kappa-B signaling pathway in patients with unstable angina and elevated levels of C-reactive protein evidence for a direct proinflammatory effect of azide and lipopolysaccharide-free C-reactive protein on human monocytes via nuclear factor kappa-B activation

OBJECTIVES

Our study investigated: 1) the contribution of nuclear factor kappa-B (NF-kappaB) signaling pathway to the enhanced inflammatory response observed in unstable angina (UA) patients with elevated levels of C-reactive protein (CRP); and 2) whether CRP may have direct proinflammatory effects via NF-kappaB activation.

BACKGROUND

Unstable angina patients with elevated CRP have enhanced inflammatory response and increased risk of persistent instability, myocardial infarction, and death.

METHODS

We studied 28 patients with history of UA and persistently elevated CRP (>3 mg/l) followed for 24 months and free of symptoms for at least 6 months (group 1), 14 patients with history of UA and low CRP (group 2), and 24 patients with chronic stable angina and low CRP (group 3). Peripheral blood monocytes were analyzed for spontaneous NF-kappaB activation and interleukin (IL)-6 and tumor necrosis factor (TNF)-alpha production. To assess the direct proinflammatory effects of CRP, monocytes from 8 healthy subjects were stimulated in vitro with increasing doses of CRP (5 to 10 to 25 microg/ml), lipopolysaccharide (LPS) (1 to 10 ng/ml), or both.

RESULTS

Spontaneous NF-kappaB activation in vivo was demonstrated in 82% of group 1 versus 14% of group 2 and 21% of group 3 patients (p < 0.001). Interleukin-6 and TNF-alpha production was significantly correlated with the NF-kappaB activation status (r = 0.55, p < 0.001 and r = 0.53, p = 0.006, respectively). Patients with NF-kappaB activation had recurrence of acute coronary events (60% vs. 28%; p = 0.017). C-reactive protein induced a significant but modest in vitro NF-kappaB activation in human monocytes (p = 0.002). Coincubation with LPS produced a greater-than-additive response (p < 0.01 vs. CRP and LPS alone).

CONCLUSIONS

Nuclear factor kappa-B activation might represent a mechanism by which CRP amplifies and perpetuates the inflammatory component of acute coronary syndromes and influences the clinical outcome.

Neopterin induces pro-atherothrombotic phenotype in human coronary endothelial cells

BACKGROUND

Inflammation plays a pivotal role in atherothrombosis. Recent data indicate that serum levels of neopterin, a marker of inflammation and immune modulator secreted by monocytes/macrophages, are elevated in patients with acute coronary syndromes and seem to be a prognostic marker for major cardiovascular events. The aim of the present study was to determine whether neopterin might affect the thrombotic and atherosclerotic characteristics of human coronary artery endothelial cells (HCAECs).

METHODS AND RESULTS

In HCAECs, neopterin induced TF-mRNA transcription as demonstrated by real time polymerase chain reaction and expression of functionally active tissue factor (TF) as demonstrated by procoagulant activity assay, and of cellular adhesion molecules (CAMs) as demonstrated by FACS analysis, in a dose-dependent fashion. These neopterin effects were prevented by lovastatin, a HMG-CoA reductase inhibitor. Neopterin-induced TF and CAMs expression was mediated by oxygen free radicals through the activation of the transcription factor, nuclear factor-kappa B (NF-kappaB), as demonstrated by electrophoretic mobility shift assay and by suppression of CAMs and TF expression by superoxide dismutase and by NF-kappaB inhibitor, pyrrolidine-dithio-carbamate ammonium.

CONCLUSIONS

These data indicate that neopterin exerts direct effects on HCAECs by promoting CAMs and TF expression and support the hypothesis that neopterin, besides representing a marker of inflammation, might be an effector molecule able to induce a pro-atherothrombotic phenotype in cells of the coronary circulation.

Transcription factor and kinase-mediated signaling in atherosclerosis and vascular injury

Our understanding of the molecular signaling pathways regulating the initiation and progression of atherosclerosis or remodeling in response to injury has begun to cross the boundaries from regulation of well-described canonical pathways to the interplay between these pathways. The focus of this review is to summarize our current understanding of a finite group of transcription factors and kinases involved in vascular injury and atherosclerosis, including nuclear factor-kappaB (NF-kappaB), early growth response factor-1 (Egr-1), activator protein-1 (AP-1), hypoxia inducible factor-1alpha (HIF-1alpha), homeobox, and T cell factor/lymphoid enhancer factor (Tcf-Lef), as well as the kinases janus kinase/signal transducers and activators of transcription (JAK/STAT), protein kinase C (PKC), p38, Rho, ERK5, JNK, p44/p42, and phosphoinositide 3 (PI3) kinase/AKT.