Activation of NF-kappaB induced by H(2)O(2) and TNF-alpha and its effects on ICAM-1 expression in endothelial cells

Intercellular Adhesion Molecule 1 (ICAM-1): An Inflammatory Regulator with Potential Implications in Ferroptosis and Parkinson's Disease

Intercellular adhesion molecule 1 (ICAM-1/CD54), a transmembrane glycoprotein, has been considered as one of the most important adhesion molecules during leukocyte recruitment. It is encoded by the ICAM1 gene and plays a central role in inflammation. Its crucial role in many inflammatory diseases such as ulcerative colitis and rheumatoid arthritis are well established. Given that neuroinflammation, underscored by microglial activation, is a key element in neurodegenerative diseases such as Parkinson's disease (PD), we investigated whether ICAM-1 has a role in this progressive neurological condition and, if so, to elucidate the underpinning mechanisms. Specifically, we were interested in the potential interaction between ICAM-1, glial cells, and ferroptosis, an iron-dependent form of cell death that has recently been implicated in PD. We conclude that there exist direct and indirect (via glial cells and T cells) influences of ICAM-1 on ferroptosis and that further elucidation of these interactions can suggest novel intervention for this devastating disease.

Mitochondria-derived damage-associated molecular patterns and inflammation in the ischemic-reperfused heart

Cardiac cell death after myocardial infarction release endogenous structures termed damage-associated molecular patterns (DAMPs) that trigger the innate immune system and initiate a sterile inflammation in the myocardium. Cardiomyocytes are energy demanding cells and 30% of their volume are mitochondria. Mitochondria are evolutionary endosymbionts originating from bacteria containing molecular patterns similar to bacteria, termed mitochondrial DAMPs (mDAMPs). Consequently, mitochondrial debris may be particularly immunogenic and damaging. However, the role of mDAMPs in myocardial infarction is not clarified. Identifying the most harmful mDAMPs and inhibiting their early inflammatory signaling may reduce infarct size and the risk of developing post-infarct heart failure. The focus of this review is the role of mDAMPs in the immediate pro-inflammatory phase after myocardial infarction before arrival of immune cells in the myocardium. We discuss different mDAMPs, their role in physiology and present knowledge regarding their role in the inflammatory response of acute myocardial infarction.

Downregulation of VAP-1 in OSCC suppresses tumor growth and metastasis via NF-κB/IL-8 signaling and reduces neutrophil infiltration

BACKGROUND

Vascular adhesion protein-1 (VAP-1) is believed to play a role in inflammation. Studies have suggested that VAP-1-mediated activation of inflammation is dependent on NF-κB, leading to secretion of the interleukin(IL)-8; however, no reports have addressed the association between VAP-1 and NF-κB/IL-8 signaling in oral squamous cell carcinoma (OSCC). This study aimed to investigate the role of VAP-1 in OSCC and further explore whether VAP-1 is involved in the regulation of neutrophil infiltration in the tumor microenvironment (TME).

METHODS

Immunochemistry staining was used to observe VAP-1 expression. CCK-8 and Transwell assays were used to measure cell proliferation, migration, and invasion. OSCC xenograft mouse models were used for in vivo verification of the VAP-1 function. The expression of NF-κB and IL-8 were determined by qRT-PCR and western blot. ELISA for IL-8 was also conducted. The relationship between VAP-1 expression and neutrophil infiltration was analyzed by immunofluorescence.

RESULTS

VAP-1 was overexpressed in human OSCC tissues. Downregulation of VAP-1 suppressed OSCC cells proliferation, migration, and invasion in vitro and inhibited tumor proliferation and metastasis in vivo. Additionally, downregulation of VAP-1 inhibited NF-κB/IL-8 signaling in vitro and in vivo. VAP-1 expression was positively correlated with neutrophil infiltration in human OSCC tissues. Moreover, blocking VAP-1 decreased neutrophil infiltration by reducing IL-8 production.

CONCLUSIONS

VAP-1 downregulation in OSCC suppresses tumor growth and metastasis by inhibiting NF-κB/IL-8 signaling and reducing neutrophil infiltration in the TME, suggesting that VAP-1 may be a potential therapeutic target for OSCC.

Metformin in cardiovascular diabetology: a focused review of its impact on endothelial function

As a first-line treatment for diabetes, the insulin-sensitizing biguanide, metformin, regulates glucose levels and positively affects cardiovascular function in patients with diabetes and cardiovascular complications. Endothelial dysfunction (ED) represents the primary pathological change of multiple vascular diseases, because it causes decreased arterial plasticity, increased vascular resistance, reduced tissue perfusion and atherosclerosis. Caused by “biochemical injury”, ED is also an independent predictor of cardiovascular events. Accumulating evidence shows that metformin improves ED through liver kinase B1 (LKB1)/5'-adenosine monophosphat-activated protein kinase (AMPK) and AMPK-independent targets, including nuclear factor-kappa B (NF-κB), phosphatidylinositol 3 kinase-protein kinase B (PI3K-Akt), endothelial nitric oxide synthase (eNOS), sirtuin 1 (SIRT1), forkhead box O1 (FOXO1), krüppel-like factor 4 (KLF4) and krüppel-like factor 2 (KLF2). Evaluating the effects of metformin on endothelial cell functions would facilitate our understanding of the therapeutic potential of metformin in cardiovascular diabetology (including diabetes and its cardiovascular complications). This article reviews the physiological and pathological functions of endothelial cells and the intact endothelium, reviews the latest research of metformin in the treatment of diabetes and related cardiovascular complications, and focuses on the mechanism of action of metformin in regulating endothelial cell functions.

Myeloperoxidase: A versatile mediator of endothelial dysfunction and therapeutic target during cardiovascular disease

Myeloperoxidase (MPO) is a prominent mammalian heme peroxidase and a fundamental component of the innate immune response against microbial pathogens. In recent times, MPO has received considerable attention as a key oxidative enzyme capable of impairing the bioactivity of nitric oxide (NO) and promoting endothelial dysfunction; a clinically relevant event that manifests throughout the development of inflammatory cardiovascular disease. Increasing evidence indicates that during cardiovascular disease, MPO is released intravascularly by activated leukocytes resulting in its transport and sequestration within the vascular endothelium. At this site, MPO catalyzes various oxidative reactions that are capable of promoting vascular inflammation and impairing NO bioactivity and endothelial function. In particular, MPO catalyzes the production of the potent oxidant hypochlorous acid (HOCl) and the catalytic consumption of NO via the enzyme's NO oxidase activity. An emerging paradigm is the ability of MPO to also influence endothelial function via non-catalytic, cytokine-like activities. In this review article we discuss the implications of our increasing knowledge of the versatility of MPO's actions as a mediator of cardiovascular disease and endothelial dysfunction for the development of new pharmacological agents capable of effectively combating MPO's pathogenic activities. More specifically, we will (i) discuss the various transport mechanisms by which MPO accumulates into the endothelium of inflamed or diseased arteries, (ii) detail the clinical and basic scientific evidence identifying MPO as a significant cause of endothelial dysfunction and cardiovascular disease, (iii) provide an up-to-date coverage on the different oxidative mechanisms by which MPO can impair endothelial function during cardiovascular disease including an evaluation of the contributions of MPO-catalyzed HOCl production and NO oxidation, and (iv) outline the novel non-enzymatic mechanisms of MPO and their potential contribution to endothelial dysfunction. Finally, we deliver a detailed appraisal of the different pharmacological strategies available for targeting the catalytic and non-catalytic modes-of-action of MPO in order to protect against endothelial dysfunction in cardiovascular disease.

Extracellular miR-146a-5p Induces Cardiac Innate Immune Response and Cardiomyocyte Dysfunction

Previous studies have demonstrated that transient myocardial ischemia leads to release of cellular nucleic acids such as RNA. Extracellular RNA reportedly plays a pivotal role in myocardial inflammation and ischemic injury in animals. RNA profiling has identified that numerous microRNA (miRNAs), such as ss-miR-146a-5p, are upregulated in plasma following myocardial ischemia, and certain uridine-rich miRNAs exhibit strong proinflammatory effects in immune cells via ssRNA-sensing mechanism. However, the effect of extracellular miRNAs on myocardial inflammation and cardiac cell function remains unknown. In this study, we treated adult mouse cardiomyocytes with miR-146a-5p loaded in extracellular vesicles and observed a dose- and TLR7-dependent production of CXCL-2, IL-6, and TNF-α. In vivo, a single dose of myocardial injection of miR-146a-5p induced both cytokine expression (CXCL2, IL-6, and TNF-α) and innate immune cell activation (CD45⁺ leukocytes, Ly6C^mid+ monocytes, Ly6G⁺ neutrophils), which was significantly attenuated in the hearts of TLR7 KO mice. We discovered that conditioned media from miR-146a-treated macrophages stimulated proinflammatory cytokine production in adult cardiomyocytes and significantly inhibited their sarcomere shortening. Finally, using an electric cell impedance-sensing assay, we found that the conditioned media from miR-146a-treated cardiac fibroblasts or cardiomyocytes impaired the barrier function of coronary artery endothelial cells. Taken together, these data demonstrate that extracellular miR-146a-5p activates multiple cardiac cells and induces myocardial inflammation and cardiomyocyte dysfunction via intercellular interaction and innate immune TLR7 nucleic acid sensing.

Nitric oxide and oxidative stress pathways do not contribute to sex differences in renal injury and function in Dahl SS/Jr rats

The burden of hypertension in the United States is increasing and yields significant morbidity and mortality, and sex differences in hypertension are widely recognized. Reduced nitric oxide (NO) bioavailability and increased oxidative stress are known to contribute to the pathogenesis of hypertensive renal injury, and but their contributions to sex differences in injury progression of are undefined. Our purpose was to test the hypothesis that male hypertensive rats have accelerated renal injury compared to females and to determine the contributions of the nitric oxide pathway and oxidative stress in these differences. Male and female Dahl SS/Jr rats, a model that spontaneously develops hypertension with age, were allowed to age on a 0.3% NaCl diet until 3 or 6 months of age, at which points blood pressure was measured and plasma, tissue, and urine were collected. While no significant sex differences in blood pressure were present at either time point, renal injury measured by urine protein excretion was more severe (male = 44.9 ± 6; female = 15±3 mg/day/100 g bw, p = .0001), and renal function was reduced (male = 0.48 ± 0.02; female = 0.7 ± 0.03 ml min-1  g-1 kw, p = .001) in males compared to females with age. Both male and female rats exhibited reduced nitric oxide metabolites (3 months: male = 0.65 ± 0.1; female = 0.74 ± 0.3; 6 months: male = 0.16 ± 0.1; female = 0.41 ± 0.1 ml min-1  g-1 kw, p, age = 0.02, p, sex = 0.3). Levels of urinary TBARS were similar (3 months: male = 20±1.5; female = 23±1.8; 6 months: male = 26±4.8; female = 23±4.7µM day g-1 kw, p, age = 0.4, p, sex = 0.9), extracellular superoxide dismutase (EC SOD) mRNA was greater in females (3 months: male = 0.35 ± 0.03; female = 1.4 ± 0.2; 6 months: male = 0.4 ± 0.05; female = 1.3 ± 0.1 normalized counts, p, age = 0.7, p, sex < 0.0001), but EC SOD protein expression was not different (3 months: male = 0.01 ± 0.002; female = 0.01 ± 0.002; 6 months: male = 0.02 ± 0.004; female = 0.01 ± 0.002 relative density, p, age = 0.2, p, sex = 0.8). These data support the presence of significant sex differences in renal injury and function in the Dahl S rat and identify a need for further study into the mechanisms involved.

Metabolic Inflammation-A Role for Hepatic Inflammatory Pathways as Drivers of Comorbidities in Nonalcoholic Fatty Liver Disease?

Nonalcoholic fatty liver disease (NAFLD) is a global and growing health concern. Emerging evidence points toward metabolic inflammation as a key process in the fatty liver that contributes to multiorgan morbidity. Key extrahepatic comorbidities that are influenced by NAFLD are type 2 diabetes, cardiovascular disease, and impaired neurocognitive function. Importantly, the presence of nonalcoholic steatohepatitis and advanced hepatic fibrosis increase the risk for systemic comorbidity in NAFLD. Although the precise nature of the crosstalk between the liver and other organs has not yet been fully elucidated, there is emerging evidence that metabolic inflammation-in part, emanating from the fatty liver-is the engine that drives cellular dysfunction, cell death, and deleterious remodeling within various body tissues. This review describes several inflammatory pathways and mediators that have been implicated as links between NAFLD and type 2 diabetes, cardiovascular disease, and neurocognitive decline.

It takes more than two to tango: mechanosignaling of the endothelial surface

The endothelial surface is a highly flexible signaling hub which is able to sense the hemodynamic forces of the streaming blood. The subsequent mechanosignaling is basically mediated by specific structures, like the endothelial glycocalyx building the top surface layer of endothelial cells as well as mechanosensitive ion channels within the endothelial plasma membrane. The mechanical properties of the endothelial cell surface are characterized by the dynamics of cytoskeletal proteins and play a key role in the process of signal transmission from the outside (lumen of the blood vessel) to the interior of the cell. Thus, the cell mechanics directly interact with the function of mechanosensitive structures and ion channels. To precisely maintain the vascular tone, a coordinated functional interdependency between endothelial cells and vascular smooth muscle cells is necessary. This is given by the fact that mechanosensitive ion channels are expressed in both cell types and that signals are transmitted via autocrine/paracrine mechanisms from layer to layer. Thus, the outer layer of the endothelial cells can be seen as important functional mechanosensitive and reactive cellular compartment. This review aims to describe the known mechanosensitive structures of the vessel building a bridge between the important role of physiological mechanosignaling and the proper vascular function. Since mutations and dysfunction of mechanosensitive proteins are linked to vascular pathologies such as hypertension, they play a potent role in the field of channelopathies and mechanomedicine.

Redox Regulation of the Microcirculation

The microcirculation maintains tissue homeostasis through local regulation of blood flow and oxygen delivery. Perturbations in microvascular function are characteristic of several diseases and may be early indicators of pathological changes in the cardiovascular system and in parenchymal tissue function. These changes are often mediated by various reactive oxygen species and linked to disruptions in pathways such as vasodilation or angiogenesis. This overview compiles recent advances relating to redox regulation of the microcirculation by adopting both cellular and functional perspectives. Findings from a variety of vascular beds and models are integrated to describe common effects of different reactive species on microvascular function. Gaps in understanding and areas for further research are outlined. © 2020 American Physiological Society. Compr Physiol 10:229-260, 2020.

Alanyl-glutamine Heals Indomethacin-induced Gastric Ulceration in Rats Via Antisecretory and Anti-apoptotic Mechanisms

OBJECTIVES

Alanylglutamine (AG) is a dipeptide that fuels enterocytes and has a coadjuvant role during gut healing. The current study aimed to investigate the potential ulcer-healing effect of AG in indomethacin-induced gastropathy.

METHODS

Animals (n = 10 rats/group) were randomly allocated into 5 groups. Gastric ulcerated rats were administered AG, AG + dexamethasone, or pantoprazole after indomethacin exposure.

RESULTS

Comparable to pantoprazole, AG inhibited H-KATPase pump, and elevated the pH of gastric juice. Moreover, the dipeptide increased the serum/mucosal contents of glucagon-like peptide-1 (GLP-1), pS473-Akt, and cyclin-D1. On the contrary, AG abated serum tumor necrosis factor-α and gastric mucosal content of pS45-β catenin, pS9-GSK3β, pS133-CREB, pS536-NF-κB, H2O2, claudin-1, and caspase-3. The administration of dexamethasone before AG hampered its effect on almost all the measured parameters.

CONCLUSIONS

AG confers its antiulcerogenic/antisecretory potentials by repressing the proton pump to increase the gastric juice pH via boosting p-CREB, p-Akt, p-GSK-3β, and GLP-1. Also, it inhibits apoptosis through suppressing nuclear factor-kappa B/tumor necrosis factor-α/H2O2/claudin-1 cue. This trajectory contributes to loosen the tight junction priming AG-mediated GLP-1/β-catenin/cyclin-D1 that results in pronounced increase in gastric mucosa proliferation. Therefore, the crosstalk between multiple pathways orchestrates the action of AG against gastric ulceration.

Nepeta angustifolia attenuates responses to vascular inflammation in high glucose-induced human umbilical vein endothelial cells through heme oxygenase-1 induction

ETHNOPHARMACOLOGICAL RELEVANCE

The traditional folk medicine Nepeta angustifolia C. Y. Wu (NA) reportedly possesses various biological activities, such as anti-inflammatory, analgesic, antihypoxia, and antifatigue effects. In this study, we evaluated the anti-vascular inflammation effects of N. angustifolia extract in human umbilical vein endothelial cells (HUVECs) induced by high glucose (HG) as well as the underlying mechanisms and verified its activity in diabetic rats.

MATERIALS AND METHODS

HUVECs were exposed to 25 mM glucose to induce endothelial dysfunction. Adhesion molecule expression and reactive oxygen species (ROS) were assayed. IκB and IκB phosphorylation, nuclear factor-κB (NF-κB), HO-1 and nuclear factor erythroid 2-related factor 2 (Nrf2) were examined by Western blot. Nuclear localisation of Nrf2 was also examined using immunofluorescence. The in vivo study of NA was tested in diabetic rats in which the thoracic aorta and serum were collected to observe aorta histological change, and evaluate endothelial function and vascular inflammation.

RESULTS

The results revealed that HG can significantly promote the generation of ROS, the expression of cell adhesion molecules (CAMs), and the phosphorylation and degradation of IκB and NF-κB activation in HUVECs. These HG-induced phenomena were suppressed by NA-induced heme oxygenase (HO)- 1 expression in a dose- and time-dependent manner by activating Nrf2. The HO-1 inhibitor tin protoporphyrin also dramatically reversed the NA-induced inhibition of CAM expression and the reduction in ROS production. Furthermore, NA also elicited anti-vascular dysfunction effects in diabetic rats, where endothelial function was improved and vascular inflammation was alleviated.

CONCLUSION

All these findings indicated that NA attenuated high glucose-induced vascular dysfunction in vitro and in vivo.

Myeloperoxidase in the inflamed colon: A novel target for treating inflammatory bowel disease

Inflammatory bowel disease (IBD) is a debilitating disorder involving inflammation of the gastrointestinal tract. The incidence of IBD is increasing worldwide. Immunological responses in the gastrointestinal (GI) tract to altered gut microbiota, mucosal injury and loss of intestinal epithelial cell function all contribute to a complex mechanism underlying IBD pathogenesis. Immune cell infiltration, particularly neutrophils, is a histological feature of IBD. This innate immune response is aimed at resolving intestinal damage however, neutrophils and monocytes that are recruited and accumulate in the GI wall, participate in IBD pathogenesis by producing inflammatory cytokines and soluble mediators such as reactive oxygen species (ROS; one- and two-electron oxidants). Unregulated ROS production in host tissue is linked to oxidative damage and inflammation and may potentiate mucosal injury. Neutrophil-myeloperoxidase (MPO) is an abundant granule enzyme that catalyses production of potent ROS; biomarkers of oxidative damage (and MPO protein) are increased in the mucosa of patients with IBD. Targeting MPO may mitigate oxidative damage to host tissue and ensuing inflammation. Here we identify mechanisms by which MPO activity perpetuates inflammation and contributes to host-tissue injury in patients with IBD and discuss MPO as a potential therapeutic target to protect the colon from inflammatory injury.

VEGF Neutralization Plus CTLA-4 Blockade Alters Soluble and Cellular Factors Associated with Enhancing Lymphocyte Infiltration and Humoral Recognition in Melanoma

Immune recognition of tumor targets by specific cytotoxic lymphocytes is essential for the effective rejection of tumors. A phase I clinical trial of ipilimumab (an antibody that blocks CTLA-4 function) in combination with bevacizumab (an antibody that inhibits angiogenesis) in patients with metastatic melanoma found favorable clinical outcomes were associated with increased tumor endothelial activation and lymphocyte infiltration. To better understand the underlying mechanisms, we sought features and factors that changed as a function of treatment in patients. Ipilimumab plus bevacizumab (Ipi-Bev) increased tumor vascular expression of ICAM1 and VCAM1. Treatment also altered concentrations of many circulating cytokines and chemokines, including increases of CXCL10, IL1α, TNFα, CXCL1, IFNα2, and IL8, with decreases in VEGF-A in most patients. IL1α and TNFα induced expression of E-selectin, CXCL1, and VCAM1 on melanoma tumor-associated endothelial cells (TEC) in vitro and promoted adhesion of activated T cells onto TEC. VEGFA inhibited TNFα-induced expression of ICAM1 and VCAM1 and T-cell adhesion, which was blocked by bevacizumab. CXCL10 promoted T-cell migration across TEC in vitro, was frequently expressed by melanoma cells, and was upregulated in a subset of tumors in treated patients. Robust upregulation of CXCL10 in tumors was accompanied by increased T-cell infiltration. Ipi-Bev also augmented humoral immune responses recognizing targets in melanoma, tumor endothelial, and tumor mesenchymal stem cells. Our findings suggest that Ipi-Bev therapy augments immune recognition in the tumor microenvironment through enhancing lymphocyte infiltration and antibody responses. IL1α, TNFα, and CXCL10, together with VEGF neutralization, contribute to Ipi-Bev-induced melanoma immune recognition. Cancer Immunol Res; 4(10); 858-68. ©2016 AACR.

Endothelial cell regulation of pulmonary vascular tone, inflammation, and coagulation

The pulmonary endothelium represents a heterogeneous cell monolayer covering the luminal surface of the entire lung vasculature. As such, this cell layer lies at a critical interface between the blood, airways, and lung parenchyma, and must act as a selective barrier between these diverse compartments. Lung endothelial cells are able to produce and secrete mediators, display surface receptor, and cellular adhesion molecules, and metabolize circulating hormones to influence vasomotor tone, both local and systemic inflammation, and coagulation functions. In this review, we will explore the role of the pulmonary endothelium in each of these systems, highlighting key regulatory functions of the pulmonary endothelial cell, as well as novel aspects of the pulmonary endothelium in contrast to the systemic cell type. The interactions between pulmonary endothelial cells and both leukocytes and platelets will be discussed in detail, and wherever possible, elements of endothelial control over physiological and pathophysiological processes will be examined.

Maternal serum uric acid concentration is associated with the expression of tumour necrosis factor-α and intercellular adhesion molecule-1 in patients with preeclampsia

We aimed to investigate whether there is a correlation between elevated serum uric acid (SUA) concentration and endothelial inflammatory response in women with preeclampsia (PE). On the basis of clinical and laboratory findings, patients were assigned to three groups: normal blood pressure (Control (Con)), gestational hypertension (GH) and PE (n=50 in each group). SUA concentration was measured by spectrophotometry, and serum tumour necrosis factor-α (TNF-α) and intercellular adhesion molecule-1 (ICAM-1) levels were measured by enzyme-linked immunosorbent assay. Western blotting and immunohistochemical staining were also used to detect the changes in TNF-α and ICAM-1 expression in subcutaneous fat tissue. PE patients showed significantly higher systolic and diastolic blood pressures compared with Con and GH pregnant women (P=0.02 and P=0.02, respectively). The changes of body mass index (ΔBMI) before and after pregnancy and 24-h urine protein were significantly different among the three groups (P<0.001). Maternal SUA, TNF-α and soluble ICAM-1 (sICAM-1) levels were significantly increased in the patients with PE (P<0.05) compared with the other two groups. Scatterplot analysis revealed that elevated SUA concentration positively correlated with TNF-α and sICAM-1 in pregnant women. Moreover, vessels in subcutaneous fat tissues of preeclamptic patients showed intense TNF-α and ICAM-1 staining compared with Con and GH patients. The results support that, to a certain extent, elevated SUA concentration is significantly associated with inflammation of maternal systemic vasculature as indicated by increased TNF-α and ICAM-1 expression in women with PE.

Green Tea Polyphenol Epigallocatechin-3-Gallate Attenuates TNF-α-Induced Intercellular Adhesion Molecule-1 Expression and Monocyte Adhesion to Retinal Pigment Epithelial Cells

Epigallocatechin-3-gallate (EGCG) is a major polyphenol component of green tea (Camellia sinensis) and demonstrates anti-oxidant, anticancer and anti-inflammatory properties. EGCG has been shown to protect retinal pigment epithelium (RPE) against oxidative stress-induced cell death. The pathogenesis of diseases in the retina is usually initiated by local inflammation at the RPE cell layer, and inflammation is mostly associated with leukocyte migration and the secretion of pro-inflammatory cytokines. Whether EGCG can modulate the cytokine-induced inflammatory response of RPE, particularly leukocyte migration, has not been clearly elucidated, and was therefore the objective of this study. ARPE-19 cells were cultured with different concentrations of TNF-α in the presence or absence of EGCG to different time points. Intracellular reactive oxygen species (ROS) levels were determined. Intercellular adhesion molecule (ICAM)-1 and phosphor-NF-κB and IκB expression were determined by Western blot analysis. Phosphor-NF-κB nuclear translocation and monocyte–RPE adhesion were investigated using immunofluorescence confocal laser scanning microscopy. Scanning electron microscopy (SEM) was carried out to further determine the ultrastructure of monocyte–RPE adhesion. The results demonstrated that TNF-α modulated inflammatory effects in ARPE-19 by induction of ROS and up-regulation of ICAM-1 expression. Moreover, TNF-α-induced phosphor-NF-κB nuclear translocation, increased phosphor-NF-κB expression and IκB degradation, and increased the degree of monocyte–RPE adhesion. Pretreating the cells with EGCG ameliorated the inflammatory effects of TNF-α. The results indicated that EGCG significantly exerts anti-inflammatory effects in ARPE-19 cells, partly as a suppressor of TNF-α signaling and that the inhibition was mediated via the NF-κB pathway.

Effect of hyperketonemia (Acetoacetate) on nuclear factor-κB and p38 mitogen-activated protein kinase activation mediated intercellular adhesion molecule 1 upregulation in endothelial cells

BACKGROUND

Hyperketonemia is a pathological condition observed in patients with type 1 diabetes and ketosis-prone diabetes (KPD), which results in increased blood levels of acetoacetate (AA) and β-hydroxybutyrate (BHB). Frequent episodes of hyperketonemia are associated with a higher incidence of vascular disease. We examined the hypothesis that hyperketonemia activates the nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways that regulate intercellular adhesion molecule 1 (ICAM-1) expression in endothelial cells.

METHODS

Human umbilical vein endothelial cells (HUVECs) were cultured with AA (0-8 mM) or BHB (0-10 mM) for 0-24 hr. Western blotting was used to determine NF-κB activation in whole-cell lysates. ICAM-1 expression was measured using flow cytometry.

RESULTS

RESULTS show a 2.4-fold increase in NF-κB activation in cells treated with 8 mM AA compared to the control. BHB had little or no effect on NF-κB activation. Pretreatment with a reactive oxygen species (ROS) inhibitor [N-acetyl-l-cysteine (NAC)] reduced NF-κB to near-control levels. The expression of AA-induced ICAM-1 was significantly reduced when cells were pretreated with either NAC or p38 MAPK inhibitor.

CONCLUSIONS

These results suggest that NF-κB and p38 MAPK mediate upregulation of ICAM-1 expression in endothelial cells exposed to elevated levels of AA, which may contribute to the development of vascular disease in diabetes.

Regulation of NF-κB signaling by oxidized glycerophospholipid and IL-1β induced miRs-21-3p and -27a-5p in human aortic endothelial cells

Exposure of endothelial cells (ECs) to agents such as oxidized glycerophospholipids (oxGPs) and cytokines, known to accumulate in atherosclerotic lesions, perturbs the expression of hundreds of genes in ECs involved in inflammatory and other biological processes. We hypothesized that microRNAs (miRNAs) are involved in regulating the inflammatory response in human aortic endothelial cells (HAECs) in response to oxGPs and interleukin 1β (IL-1β). Using next-generation sequencing and RT-quantitative PCR, we characterized the profile of expressed miRNAs in HAECs pre- and postexposure to oxGPs. Using this data, we identified miR-21-3p and miR-27a-5p to be induced 3- to 4-fold in response to oxGP and IL-1β treatment compared with control treatment. Transient overexpression of miR-21-3p and miR-27a-5p resulted in the downregulation of 1,253 genes with 922 genes overlapping between the two miRNAs. Gene Ontology functional enrichment analysis predicted that the two miRNAs were involved in the regulation of nuclear factor κB (NF-κB) signaling. Overexpression of these two miRNAs leads to changes in p65 nuclear translocation. Using 3' untranslated region luciferase assay, we identified 20 genes within the NF-κB signaling cascade as putative targets of miRs-21-3p and -27a-5p, implicating these two miRNAs as modulators of NF-κB signaling in ECs.

Tomato extract and the carotenoids lycopene and lutein improve endothelial function and attenuate inflammatory NF-κB signaling in endothelial cells

OBJECTIVES

In our previous research the antihypertensive properties of lycopene-containing tomato oleoresin have been revealed. The present study was aimed to assess if oleoresin interferes in the inflammatory signalling in endothelial cells, imitating reduction of inflammatory processes in the vessel wall and in this way to propose the mechanism for the reduction of blood pressure by oleoresin.

METHODS AND RESULTS

A wide number of functional and inflammatory markers were investigated in two cultured endothelial cell models [EA.hy926 and human umbilical vein endothelial cell (HUVEC)], exposed to oleoresin and carotenoids lycopene and lutein. All the carotenoids significantly improved basic endothelial function as measured by increased nitric oxide and decreased endothelin (ET-1) release. They were effective in attenuation of inflammatory nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signalling: decrease of tumour necrosis factor-alpha (TNF-α)-induced leukocytes adhesion, expression of adhesion molecules inter-cellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1), and nuclear translocation of NF-κB components as well as some revert of inhibitor of kappa B (IκB) ubiquitination. In addition, the carotenoids were able to inhibit NF-κB activation in transfected endothelial cells. When combined with lutein, oleoresin exerted synergistic effect on preclusion of leukocytes adhesion.

CONCLUSIONS

Prevention of over-expression of adhesion molecules through inhibition of NF-κB signalling may be one of the main mechanisms driving carotenoids to attenuate inflammatory leukocyte adhesion to endothelium. This is the first profound study on the mechanisms involved in the positive action of natural tomato products in endothelial cells.

Novel quinic acid derivative KZ-41 prevents retinal endothelial cell apoptosis without inhibiting retinoblastoma cell death through p38 signaling

PURPOSE

To determine whether a novel NF-κB inhibitor, KZ-41, can inhibit melphalan's actions on retinal endothelial cell (REC) inflammation and apoptosis, without eliminating the chemotherapeutic efficacy of melphalan on cell death of retinoblastoma cells (Y79).

METHODS

RECs were cultured in M131 medium supplemented with growth factors and antibiotics. Once cells reached confluence, they were treated with or without 10 μM KZ-41, following treatment with 4 μg/mL melphalan. Cell proteins were extracted and analyzed for intracellular adhesion molecule 1 (ICAM-1) levels and Cell Death ELISA. RECs were also transfected with or without NF-κB siRNA or treated with SB202190 (p38 [mitogen activated protein kinase] MAPK inhibitor) before melphalan treatment to determine the involvement of NF-κB and p38 MAPK in REC apoptosis and ICAM-1 levels. We also cultured retinoblastoma cells (Y79) in RMPI-1640 medium supplemented with 20% fetal bovine serum and performed a Cell Death ELISA after melphalan + KZ-41 treatment to determine if the treatments altered melphalan's ability to promote cell death of Y79 cells.

RESULTS

KZ-41 inhibited melphalan-stimulation of ICAM-1 levels and REC apoptosis, whereas KZ-41 did not alter melphalan's effects on Y79 cells. KZ-41's protective effects on REC were mediated through p38 MAPK activation. Although KZ-41 blocked both NF-κB- and p38 MAPK-dependent ICAM-1 stimulation; the p38 MAPK/ICAM-1 pathway appears to be the primary pathway involved in melphalan-induced REC apoptosis.

CONCLUSIONS

KZ-41 protects REC against melphalan-induced upregulation of ICAM-1 and apoptosis through p38 MAPK-dependent pathways.

Current status of NADPH oxidase research in cardiovascular pharmacology

The implications of reactive oxygen species in cardiovascular disease have been known for some decades. Rationally, therapeutic antioxidant strategies combating oxidative stress have been developed, but the results of clinical trials have not been as good as expected. Therefore, to move forward in the design of new therapeutic strategies for cardiovascular disease based on prevention of production of reactive oxygen species, steps must be taken on two fronts, ie, comprehension of reduction-oxidation signaling pathways and the pathophysiologic roles of reactive oxygen species, and development of new, less toxic, and more selective nicotinamide adenine dinucleotide phosphate (NADPH) oxidase inhibitors, to clarify both the role of each NADPH oxidase isoform and their utility in clinical practice. In this review, we analyze the value of NADPH oxidase as a therapeutic target for cardiovascular disease and the old and new pharmacologic agents or strategies to prevent NADPH oxidase activity. Some inhibitors and different direct or indirect approaches are available. Regarding direct NADPH oxidase inhibition, the specificity of NADPH oxidase is the focus of current investigations, whereas the chemical structure-activity relationship studies of known inhibitors have provided pharmacophore models with which to search for new molecules. From a general point of view, small-molecule inhibitors are preferred because of their hydrosolubility and oral bioavailability. However, other possibilities are not closed, with peptide inhibitors or monoclonal antibodies against NADPH oxidase isoforms continuing to be under investigation as well as the ongoing search for naturally occurring compounds. Likewise, some different approaches include inhibition of assembly of the NADPH oxidase complex, subcellular translocation, post-transductional modifications, calcium entry/release, electron transfer, and genetic expression. High-throughput screens for any of these activities could provide new inhibitors. All this knowledge and the research presently underway will likely result in development of new drugs for inhibition of NADPH oxidase and application of therapeutic approaches based on their action, for the treatment of cardiovascular disease in the next few years.

Annexin peptide Ac2-26 suppresses TNFα-induced inflammatory responses via inhibition of Rac1-dependent NADPH oxidase in human endothelial cells

The anti-inflammatory peptide annexin-1 binds to formyl peptide receptors (FPR) but little is known about its mechanism of action in the vasculature. Here we investigate the effect of annexin peptide Ac2-26 on NADPH oxidase activity induced by tumour necrosis factor alpha (TNFα) in human endothelial cells. Superoxide release and intracellular reactive oxygen species (ROS) production from NADPH oxidase was measured with lucigenin-enhanced chemiluminescence and 2′,7′-dichlorodihydrofluorescein diacetate, respectively. Expression of NADPH oxidase subunits and intracellular cell adhesion molecule (ICAM-1) and vascular cell adhesion molecule (VCAM-1) were determined by real-time PCR and Western blot analysis. Promoter activity of nuclear factor kappa B (NFκB) was measured by luciferase activity assay. TNFα stimulated NADPH-dependent superoxide release, total ROS formation and expression of ICAM-1and VCAM-1. Pre-treatment with N-terminal peptide of annexin-1 (Ac2-26, 0.5–1.5 µM) reduced all these effects, and the inhibition was blocked by the FPRL-1 antagonist WRW4. Furthermore, TNFα-induced NFκB promoter activity was attenuated by both Ac2-26 and NADPH oxidase inhibitor diphenyliodonium (DPI). Surprisingly, Nox4 gene expression was reduced by TNFα whilst expression of Nox2, p22phox and p67phox remained unchanged. Inhibition of NADPH oxidase activity by either dominant negative Rac1 (N17Rac1) or DPI significantly attenuated TNFα-induced ICAM-1and VCAM-1 expression. Ac2-26 failed to suppress further TNFα-induced expression of ICAM-1 and VCAM-1 in N17Rac1-transfected cells. Thus, Ac2-26 peptide inhibits TNFα-activated, Rac1-dependent NADPH oxidase derived ROS formation, attenuates NFκB pathways and ICAM-1 and VCAM-1 expression in endothelial cells. This suggests that Ac2-26 peptide blocks NADPH oxidase activity and has anti-inflammatory properties in the vasculature which contributes to modulate in reperfusion injury inflammation and vascular disease.

Proteome-wide profiling of activated transcription factors with a concatenated tandem array of transcription factor response elements

Transcription factors (TFs) are families of proteins that bind to specific DNA sequences, or TF response elements (TFREs), and function as regulators of many cellular processes. Because of the low abundance of TFs, direct quantitative measurement of TFs on a proteome scale remains a challenge. In this study, we report the development of an affinity reagent that permits identification of endogenous TFs at the proteome scale. The affinity reagent is composed of a synthetic DNA containing a concatenated tandem array of the consensus TFREs (catTFRE) for the majority of TF families. By using catTFRE to enrich TFs from cells, we were able to identify as many as 400 TFs from a single cell line and a total of 878 TFs from 11 cell types, covering more than 50% of the gene products that code for the DNA-binding TFs in the genome. We further demonstrated that catTFRE pull-downs could quantitatively measure proteome-wide changes in DNA binding activity of TFs in response to exogenous stimulation by using a label-free MS-based quantification approach. Applying catTFRE on the evaluation of drug effects, we described a panoramic view of TF activations and provided candidates for the elucidation of molecular mechanisms of drug actions. We anticipate that the catTFRE affinity strategy will find widespread applications in biomedical research.

The role of serum VCAM-1 and TNF-α as predictors of mortality and morbidity in patients with chronic heart failure

BACKGROUND

To assess the prognostic significance of four inflammatory markers (TNF-α, high sensitive C-reactive protein (hs-CRP), intercellular cell adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1)) in chronic heart failure (CHF) patients with respect to individual outcomes, especially disease exacerbation and mortality.

METHODS

Plasma adhesion molecules, ICAM-1, and VCAM-1, together with TNF-α and hs-CRP were determined in 120 CHF patients and 69 healthy controls. Endothelial function was also estimated by flow-mediated brachial artery dilatation.

RESULTS

Increased levels of all investigated inflammatory markers were found in CHF patients compared to controls, with the rise more pronounced in New York Heart association (NYHA) functional IV class. Significant correlations were obtained for VCAM-1 and brain natriuretic peptide (r = 0.191; P = 0.038), as well as, ICAM-1 and endothelium-dependent vasodilatation (r = -0.235; P = 0.01). Kaplan-Meier analysis showed disease exacerbation in patients with TNF-α levels >2.78 pg/ml significantly shorter compared to those with TNF-α levels <2.78 pg/ml (log-rank test = 8.270; P = 0.004), while similar association was observed for patients with hs-CRP levels >4.76 mg/l (log-rank test = 5.052; P = 0.025) and VCAM-1 levels >1200 ng/l (log-rank test = 5.45; P = 0.020) with respect to mortality. Cox regression analysis demonstrated only VCAM-1 (HR = 4.7; 95% confidence interval (CI): 1.1-18.7; P = 0.030) as independent death predictor, while TNF-α was associated with disease exacerbation (HR = 8.2; 95%CI: 1.1-23.0; P = 0.045).

CONCLUSIONS

VCAM-1 appears to be useful in risk stratification of CHF patients and in screening, to identify subjects at risk for heart failure related events.

Tumor necrosis factor-alpha (TNF-α) is a therapeutic target for impaired cutaneous wound healing

Impaired wound healing states lead to substantial morbidity and cost with treatment resulting in an expenditure of billions of dollars per annum in the U.S. alone. Both chronic wounds and impaired acute wounds are characterized by excessive inflammation, enhanced proteolysis, and reduced matrix deposition. These confounding factors are exacerbated in the elderly, in part, as we report here, related to increased local and systemic tumor necrosis factor-alpha (TNF-α) levels. Moreover, we have used a secretory leukocyte protease inhibitor (SLPI) null mouse model of severely impaired wound healing and excessive inflammation, comparable to age-related delayed human healing, to demonstrate that topical application of anti-TNF-α neutralizing antibodies blunts leukocyte recruitment and NFκB activation, alters the balance between M1 and M2 macrophages, and accelerates wound healing. Following antagonism of TNF-α, matrix synthesis is enhanced, associated with suppression of both inflammatory parameters and NFκB binding activity. Our data suggest that inhibiting TNF-α is a critical event in reversing the severely impaired healing response associated with the absence of SLPI, and may be applicable to prophylaxis and/or treatment of impaired wound healing states in humans.

Decreased NADPH oxidase expression and antioxidant activity in cachectic skeletal muscle

BACKGROUND: Cancer cachexia is the progressive loss of skeletal muscle protein that contributes significantly to cancer morbidity and mortality. Evidence of antioxidant attenuation and the presence of oxidised proteins in patients with cancer cachexia indicate a role for oxidative stress. The level of oxidative stress in tissues is determined by an imbalance between reactive oxygen species production and antioxidant activity. This study aimed to investigate the superoxide generating NADPH oxidase (NOX) enzyme and antioxidant enzyme systems in murine adenocarcinoma tumour-bearing cachectic mice. METHODS: Superoxide levels, mRNA levels of NOX enzyme subunits and the antioxidant enzymes superoxide dismutase (SOD), glutathione peroxidise (GPx) and catalase was measured in the skeletal muscle of mice with cancer and cancer cachexia. Protein expression levels of NOX enzyme subunits and antioxidant enzyme activity was also measured in the same muscle samples. RESULTS: Superoxide levels increased 1.4-fold in the muscle of mice with cancer cachexia, and this was associated with a decrease in mRNA of NOX enzyme subunits, NOX2, p40(phox) and p67(phox) along with the antioxidant enzymes SOD1, SOD2 and GPx. Cancer cachexia was also associated with a 1.3-fold decrease in SOD1 and 2.0-fold decrease in GPx enzyme activity. CONCLUSION: Despite increased superoxide levels in cachectic skeletal muscle, NOX enzyme subunits, NOX2, p40(phox) and p67(phox), were downregulated along with the expression and activity of the antioxidant enzymes. Therefore, the increased superoxide levels in cachectic skeletal muscle may be attributed to the reduction in the activity of endogenous antioxidant enzymes.

ROS-induced ZNF580 expression: a key role for H2O2/NF-κB signaling pathway in vascular endothelial inflammation

ZNF580, a newly found C2H2 zinc finger transcription factor, was first described by Zhang (GenBank ID: AF184939). Emerging evidence has suggested that reactive oxygen species (ROS) play an important role in redox-sensitive signal transduction, and the vascular endothelium plays a critical role in the vascular inflammatory response. In this communication, we present evidence for the potential role of ZNF580 in hydrogen peroxide (H2O2)-regulated inflammation-related signaling pathways. In a human endothelial cell hybridoma line (EA.hy926), ZNF580 levels were markedly upregulated with H2O2 stimulation in different concentrations (0-400 μM) and at different time-points (0-6 h). H2O2 promoted the rapid translocation of p65 from the cytoplasm into the nucleus according to immunocytochemistry staining. In subsequent research, inhibition of NF-κB by pyrrolidine dithiocarbamate (PDTC, a selective chemical inhibitor of NF-κB) was shown to block the upregulated expression of ZNF580 that was induced by H2O2. Furthermore, transient transfection of ZNF580 resulted in an increase of the pro-inflammatory cytokine interleukin-8 (IL-8) 3.01±0.05 folds according to real-time RT-PCR and ELISA assays, which also showed significantly enhanced motility of human acute monocytic leukemia cells (THP-1). These results suggest that H2O2 upregulates the expression of ZNF580 via the NF-κB signaling pathway, and overexpression of ZNF580 plays a critical role in augmenting the release of pro-inflammatory cytokine IL-8.

The transcription factor Erg inhibits vascular inflammation by repressing NF-kappaB activation and proinflammatory gene expression in endothelial cells

OBJECTIVE

To test whether ETS-related gene (Erg) inhibits tumor necrosis factor (TNF)-α-dependent endothelial activation and inflammation.

METHODS AND RESULTS

Endothelial activation underlies many vascular diseases, including atherosclerosis. Endothelial activation by proinflammatory cytokines decreases expression of the ETS transcription factor Erg. By using human umbilical vein endothelial cells (HUVECs), we showed that Erg overexpression by adenovirus (AdErg) repressed basal and TNF-α-induced expression of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule (VCAM), and interleukin 8 (IL-8). Erg inhibited TNF-α-dependent activation of the ICAM-1 promoter, nuclear factor (NF)-κB activity, and NF-κB p65 phosphorylation. Basal NF-κB activity was also inhibited by Erg overexpression. Chromatin immunoprecipitation showed that Erg binds to the ICAM-1 proximal promoter region, which contains 7 putative ETS binding sites. To test the anti-inflammatory role of Erg in vivo, we used a murine model of TNF-α-dependent acute inflammation. The injection of AdErg into the paw decreased TNF-α-induced inflammation compared with control. Finally, staining of human coronary plaques showed loss of Erg expression from the endothelium overlaying active plaque shoulders.

CONCLUSIONS

We have identified a novel physiological anti-inflammatory pathway under the control of the transcription factor Erg; this pathway inhibits NF-κB-dependent transcription and TNF-α-induced inflammation in vivo. These results suggest a novel approach to anti-inflammatory therapies.

The effect of intracellular antioxidant delivery (catalase) on hydrogen peroxide and proinflammatory cytokine synthesis: a new therapeutic horizon

Reactive oxygen species synthesized by endothelial cells may be responsible for cell damage and altered physiologic function. After endotoxin stimulation, free radicals including H(2)O(2) are produced. We have developed a method of intracellular drug delivery using albumin microcapsules. Catalase would be an excellent compound to alter H(2)O(2) production. However, the large molecular size of catalase limits cellular penetration. Endothelial cells have been previously shown to readily phagocytoze albumin microcapsules.

METHODS

Catalase was added to an albumin solution to form a 10% solution of catalase. Microspheres from 2 to 7 microm in size were formed using a Bucchi spray dryer. Human endothelial cells were incubated with varying concentrations of microencapsulated catalase. The cells were then exposed to Escherichia coli endotoxin to determine if increased intracellular penetration of catalase would inhibit H(2)O(2), nitrate, and cytokine synthesis.

RESULTS

There was a 7.2-fold increase in endothelial intracellular catalase after 48 h incubation. H(2)O(2) was inhibited by 72%, nitrate 96%, TNF 90%, IL1 21%, IL6 42%.

CONCLUSIONS

These results demonstrate that inhibition of H(2)O(2) as a result of increased intracellular delivery of catalase inhibits proinflammatory cytokine synthesis after endotoxin exposure.

Role of hydrogen peroxide in NF-kappaB activation: from inducer to modulator

Hydrogen peroxide (H2O2) has been implicated in the regulation of the transcription factor NF-kappaB, a key regulator of the inflammatory process and adaptive immunity. However, no consensus exists regarding the regulatory role played by H2O2. We discuss how the experimental methodologies used to expose cells to H2O2 produce inconsistent results that are difficult to compare, and how the steady-state titration with H2O2 emerges as an adequate tool to overcome these problems. The redox targets of H2O2 in the NF-kappaB pathway--from the membrane to the post-translational modifications in both NF-kappaB and histones in the nucleus--are described. We also review how H2O2 acts as a specific regulator at the level of the single gene, and briefly discuss the implications of this regulation for human health in the context of kappaB polymorphisms. In conclusion, after near 30 years of research, H2O2 emerges not as an inducer of NF-kappaB, but as an agent able to modulate the activation of the NF-kappaB pathway by other agents. This modulation is generic at the level of the whole pathway but specific at the level of the single gene. Therefore, H2O2 is a fine-tuning regulator of NF-kappaB-dependent processes, as exemplified by its dual regulation of inflammation.

Regulation of renin gene expression by oxidative stress

Increased arterial pressure, angiotensin II, and cytokines each result in feedback inhibition of renin gene expression. Because angiotensin II and cytokines can stimulate reactive oxygen species production, we tested the hypothesis that oxidative stress may be a mediator of this inhibition. Treatment of renin-expressing As4.1 cells with the potent cytokine tumor necrosis factor-alpha caused an increase in the steady-state levels of cellular reactive oxygen species, which was reversed by the antioxidant N-acetylcysteine. Exogenous H(2)O(2) caused a dose- and time-dependent decrease in the level of endogenous renin mRNA and decreased the transcriptional activity of a 4.1-kb renin promoter fused to luciferase, which was maximal when the renin enhancer was present. The effect of H(2)O(2) appeared to be specific to renin, because there was no change in the expression of beta-actin or cyclophilin mRNA or transcriptional activity of the SV40 promoter. The tumor necrosis factor-alpha-induced decrease in renin mRNA was partially reversed by either N-acetylcysteine or panepoxydone, a nuclear factor kappaB (NFkappaB) inhibitor. Interestingly, H(2)O(2) did not induce NFkappaB in As4.1 cells, and panepoxydone had no effect on the downregulation of renin mRNA by H(2)O(2). The transcriptional activity of a cAMP response element-luciferase construct was decreased by both tumor necrosis factor-alpha and H(2)O(2). These data suggest that cellular reactive oxygen species can negatively regulate renin gene expression via an NFkappaB-independent mechanism involving the renin enhancer and inhibiting cAMP response element-mediated transcription. Our data further suggest that tumor necrosis factor-alpha decreases renin expression through both NFkappaB-dependent and NFkappaB-independent mechanisms, the latter involving the production of reactive oxygen species.

Unique aspects of transcriptional regulation in neurons--nuances in NFkappaB and Sp1-related factors

The unique physiology and function of neurons create differences in their cellular physiology, including their regulation of gene expression. We began several years ago exploring the relationships between the NFκB transcription factor, neuronal survival, and glutamate receptor activation in telencephalic neurons. These studies led us to conclude that this population of cells is nearly incapable of activating the NFκB that is nonetheless expressed at reasonable levels. A subset of the κB cis elements are instead bound by members of the Sp1 family in neurons. Also surprising was our discovery that Sp1 itself, typically described as ubiquitous, is severely restricted in expression within forebrain neurons; Sp4 seems to be substituted during neuronal differentiation. These findings and their implications for neuronal differentiation – as well as potential dedifferentiation during degenerative processes – are discussed here.

NADPH oxidase-dependent signaling in endothelial cells: role in physiology and pathophysiology

Reactive oxygen species (ROS) including superoxide (O(2)(.-)) and hydrogen peroxide (H(2)O(2)) are produced endogenously in response to cytokines, growth factors; G-protein coupled receptors, and shear stress in endothelial cells (ECs). ROS function as signaling molecules to mediate various biological responses such as gene expression, cell proliferation, migration, angiogenesis, apoptosis, and senescence in ECs. Signal transduction activated by ROS, "oxidant signaling," has received intense investigation. Excess amount of ROS contribute to various pathophysiologies, including endothelial dysfunction, atherosclerosis, hypertension, diabetes, and acute respiratory distress syndrome (ARDS). The major source of ROS in EC is a NADPH oxidase. The prototype phagaocytic NADPH oxidase is composed of membrane-bound gp91phox and p22hox, as well as cytosolic subunits such as p47(phox), p67(phox) and small GTPase Rac. In ECs, in addition to all the components of phagocytic NADPH oxidases, homologues of gp91(phox) (Nox2) including Nox1, Nox4, and Nox5 are expressed. The aim of this review is to provide an overview of the emerging area of ROS derived from NADPH oxidase and oxidant signaling in ECs linked to physiological and pathophysiological functions. Understanding these mechanisms may provide insight into the NADPH oxidase and oxidant signaling components as potential therapeutic targets.

Possible mechanism of the anti-inflammatory activity of ruscogenin: role of intercellular adhesion molecule-1 and nuclear factor-kappaB

Ruscogenin (RUS), first isolated from Ruscus aculeatus, also a major steroidal sapogenin of traditional Chinese herb Radix Ophiopogon japonicus, has been found to exert significant anti-inflammatory and anti-thrombotic activities. Our previous studies suggested that ruscogenin remarkably inhibited adhesion of leukocytes to a human umbilical vein endothelial cell line (ECV304) injured by tumor necrosis factor-alpha (TNF-alpha) in a concentration-dependent manner. Yet the underlying mechanisms remain unclear. In this study, the in vivo effects of ruscogenin on leukocyte migration and celiac prostaglandin E(2) (PGE(2)) level induced by zymosan A were studied in mice. Furthermore, the effects of ruscogenin on TNF-alpha-induced intercellular adhesion molecule-1 (ICAM-1) expression and nuclear factor-kappaB (NF-kappaB) activation were also investigated under consideration of their key roles in leukocyte recruitment. The results showed that ruscogenin significantly suppressed zymosan A-evoked peritoneal total leukocyte migration in mice in a dose-dependent manner, while it had no obvious effect on PGE(2) content in peritoneal exudant. Ruscogenin also inhibited TNF-alpha-induced over expression of ICAM-1 both at the mRNA and protein levels and suppressed NF-kappaB activation considerably by decreasing NF-kappaB p65 translocation and DNA binding activity. These findings provide some new insights that may explain the possible molecular mechanism of ruscogenin and Radix Ophiopogon japonicus for the inhibition of endothelial responses to cytokines during inflammatory and vascular disorders.

The role of inflammatory cytokines in endothelial dysfunction

Clinical and experimental data support a link between endothelial dysfunction and inflammation. Inflammatory cytokines are important protagonists in formation of atherosclerotic plaque, eliciting effects throughout the atherosclerotic vessel. Importantly, the development of atherosclerotic lesions, regardless of the risk factor, e.g., diabetes, hypertension, obesity, is characterized by disruption in normal function of the endothelial cells. Endothelial cells, which line the internal lumen of the vasculature, are part of a complex system that regulates vasodilation and vasoconstriction, growth of vascular smooth muscle cells, inflammation, and hemostasis, maintaining a proper blood supply to tissues and regulating inflammation and coagulation. Current concepts suggest that the earliest event in atherogenesis is endothelial dysfunction, manifested by deficiencies in the production of nitric oxide (NO) and prostacyclin. The focus of this review is to summarize recent evidence showing the effects of inflammation on vascular dysfunction in ischemic-heart disease, which may prompt new directions for targeting inflammation in future therapies.

Nicotinamide adenine dinucleotide phosphate (reduced form) oxidase is important for LPS-induced endothelial cell activation

Activation of the endothelium plays an important role in the innate immune response. This process is associated with an increase in the production of superoxide (O2-) by nicotinamide adenine dinucleotide phosphate (reduced form; NADPH) oxidase. Our objective was to determine if O2- from NADPH oxidase contributes to activation of human umbilical vein endothelial cells by LPS as it does for TNF-alpha. We used the adhesion molecule intracellular adhesion molecule 1 and cytokine IL-8 as indicators of human umbilical vein endothelial cell activation and measured O2- production with chemiluminescence. LPS increased baseline and NADPH-stimulated O2- production. The increase was reduced by tiron, a protein kinase C inhibitor (bisindolylmaleimide I hydrochloride), the flavin inhibitor (diphenylene iodonium), and by a short interfering RNA against the p22phox component of NADPH oxidase. Inhibition of NADPH oxidase with the short interfering RNA reduced the induction by LPS of intracellular adhesion molecule 1 mRNA, protein, and IL-8 release (by enzyme-linked immunosorbent assay). The production of O2- by NADPH oxidase contributes to intracellular signaling by LPS in endothelial cells as it does for TNF-alpha and helps turn on the innate immune response in these cells.