Surface Expression Of Intercellular Adhesion Molecule-1 Research Articles

Curcumin Attenuates TNF‐α‐induced Expression of Intercellular Adhesion Molecule‐1, Vascular Cell Adhesion Molecule‐1 and Proinflammatory Cytokines in Human Endometriotic Stromal Cells

Curcumin, a naturally occurring polyphenolic compound from Curcuma longa, has long been used in folk medicine as an antiinflammatory remedy in Asian countries. Endometriosis is a chronic gynecological inflammatory disorder in which immune system deregulation may play a role in its initiation and progression. A number of mediators, including cell adhesion molecules such as intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1); proinflammatory cytokines such as tumour necrosis factor-α (TNF-α), interleukin-1 (IL-1), IL-6 and IL-8; and chemokines such as monocyte chemotactic protein-1 (MCP-1), play key roles in the pathogenesis of endometriosis. The aim of our study was to explore the effect of curcumin on the expression of these critical molecules in human ectopic endometriotic stromal cells isolated from women with endometriosis. Endometriotic stromal cells treated with curcumin showed marked suppression of TNF-α-induced mRNA expression of ICAM-1 and VCAM-1. Curcumin treatment also significantly decreased the TNF-α-induced cell surface and total protein expression of ICAM-1 and VCAM-1 in a dose-dependent manner. In addition, treatment of endometriotic stromal cells with curcumin markedly inhibited TNF-α-induced secretion of IL-6, IL-8 and MCP-1. Furthermore, curcumin inhibited the activation of transcription factor NF-κB, a key regulator of inflammation, in human endometriotic stromal cells. These findings suggest that curcumin may have potential therapeutic uses in the prevention and treatment of endometriosis.

Abstract 18114: Efficacy of Apolipoprotein A-IV as a Vascular Anti-Inflammatory and Anti-Oxidant Agent

Objective: Apolipoprotein (apo) A-IV, the 3rd most abundant HDL apolipoprotein in human plasma, has anti-inflammatory properties in animal models of colitis and LPS-induced systemic inflammation. This study investigates the ability of apoA-IV to inhibit acute vascular inflammation in the NZW rabbit. Methods: A non-occlusive peri-arterial carotid collar was inserted into normocholesterolemic NZW rabbits (mean weight 3 Kg) 24 h after administering a single intravenous (iv) infusion of either saline or lipid-free apoA-IV (1 mg/kg). The animals were sacrificed 24 h post-collar insertion. Carotid arteries were extracted and analysed immunohistochemically for endothelial expression of vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1) and intima/media neutrophil infiltration (CD18+ cells). Human coronary artery endothelial cells (HCAECs) were pre-incubated for 16 h with discoidal reconstituted HDL (rHDL) containing phosphatidylcholine complexed with apoA-IV (final apoA-IV concentration 10 µM/L), then stimulated for a further 5 h with tumour necrosis factor α (TNF- α) (0.2 ng/ml). Cell surface VCAM-1 and ICAM-1 expression was measured by flow cytometry. VCAM-1 and ICAM-1 mRNA levels and the mRNA level of the anti-oxidant and anti-apoptotic enzyme 3β-hydroxysteroid-D24 reductase (DHCR24) were quantified by qPCR. Results: Relative to the saline-infused animals, a single iv infusion of lipid-free apoA-IV decreased collar-induced neutrophil infiltration by 74% and endothelial expression of ICAM-1 and VCAM-1 by 75% and 68%, respectively. Pre-incubation of TNF-α stimulated HCAECs with rHDL reduced ICAM-1 protein and mRNA levels by 34% and 48%, respectively. VCAM-1 protein and mRNA levels were decreased by 61% and 55%, respectively. Pre-incubation of HCAECs with rHDL increased DHCR24 mRNA levels 2.6-fold. Conclusion: ApoA-IV has potent vascular anti-inflammatory and anti-oxidant properties in vitro and in vivo .

Crimean-Congo Hemorrhagic Fever Virus Activates Endothelial Cells

Crimean-Congo hemorrhagic fever virus (CCHFV) causes viral hemorrhagic fever with high case-fatality rates and is geographically widely distributed. Due to the requirement for a biosafety level 4 (BSL-4) laboratory and the lack of an animal model, knowledge of the viral pathogenesis is limited. Crimean-Congo hemorrhagic fever (CCHF) is characterized by hemorrhage and vascular permeability, indicating the involvement of endothelial cells (ECs). The interplay between ECs and CCHFV is therefore important for understanding the pathogenesis of CCHF. In a previous study, we found that CCHFV-infected monocyte-derived dendritic cells (moDCs) activated ECs; however, the direct effect of CCHFV on ECs was not investigated. Here, we report that ECs are activated upon infection, as demonstrated by upregulation of mRNA levels for E-selectin, vascular cell adhesion molecule 1 (VCAM1), and intercellular adhesion molecule 1 (ICAM1). Protein levels and cell surface expression of ICAM1 responded in a dose-dependent manner to increasing CCHFV titers with concomitant increase in leukocyte adhesion. Furthermore, we examined vascular endothelial (VE) cadherin in CCHFV-infected ECs by different approaches. Infected ECs released higher levels of interleukin 6 (IL-6) and IL-8; however, stimulation of resting ECs with supernatants derived from infected ECs did not result in increased ICAM1 expression. Interestingly, the moDC-mediated activation of ECs was abrogated by addition of neutralizing tumor necrosis factor alpha (TNF-α) antibody to moDC supernatants, thereby identifying this soluble mediator as the key cytokine causing EC activation. We conclude that CCHFV can exert both direct and indirect effects on ECs.

Endothelial metallothionein expression and intracellular free zinc levels are regulated by shear stress

We examined the effects of fluid shear stress on metallothionein (MT) gene and protein expression and intracellular free zinc in mouse aorta and in human umbilical vein endothelial cells (HUVECs). Immunostaining of the endothelial surface of mouse aorta revealed increased expression of MT protein in the lesser curvature of the aorta relative to the descending thoracic aorta. HUVECs were exposed to high steady shear stress (15 dyn/cm(2)), low steady shear stress (1 dyn/cm(2)), or reversing shear stress (mean of 1 dyn/cm(2), 1 Hz) for 24 h. Gene expression of three MT-1 isoforms, MT-2A, and zinc transporter-1 was upregulated by low steady shear stress and reversing shear stress. HUVECs exposed to 15 dyn/cm(2) had increased levels of free zinc compared with cells under other shear stress regimes and static conditions. The increase in free zinc was partially blocked with an inhibitor of nitric oxide synthesis, suggesting a role for shear stress-induced endothelial nitric oxide synthase activity. Cells subjected to reversing shear stress in zinc-supplemented media (50 μM ZnSO(4)) had increased intracellular free zinc, reduced surface intercellular adhesion molecule-1 expression, and reduced monocyte adhesion compared with cells exposed to reversing shear stress in normal media. The sensitivity of intracellular free zinc to differences in shear stress suggests that intracellular zinc levels are important in the regulation of the endothelium and in the progression of vascular disease.

Insulin inhibits leukocyte–endothelium adherence via an Akt-NO-dependent mechanism in myocardial ischemia/reperfusion

Clinical evidence indicates that intensive insulin therapy during critical illness protects the endothelium and contributes to prevention of organ failure and death but the mechanisms involved remain unclear. This study was designed to test the hypothesis that insulin inhibits adherence of polymorphonuclear leukocytes (PMNs) to endothelial cells in myocardial ischemia/reperfusion (MI/R) and to investigate the underlying mechanisms. Anesthetized rabbits were subjected to MI/R (45 min/4 h) and randomly received saline, glucose-insulin-potassium (GIK) or GK respectively (2 mL/kg/h, i.v.). In vitro study was performed on cultured endothelial cells subjected to simulated ischemia/reperfusion. In vivo treatment with GIK but not GK attenuated myocardial injury as evidenced by reduced plasma creatine kinase activity, myocardial apoptosis and infarct size in MI/R rabbits compared with the saline group. Interestingly, GIK but not GK significantly decreased coronary endothelial expression of P-selectin and intercellular adhesion molecule-1 (ICAM-1), inhibited adherence of PMNs to coronary endothelium (107.7 ± 7.4 vs. 155.0 ± 9.2 PMNs/mm 2 in saline group, n = 8, P < 0.01), and therefore decreased myocardial PMNs accumulation. In cultured endothelial cells subjected to simulated ischemia/reperfusion, insulin (10 − 7 M) increased Akt activity and eNOS phosphorylation with subsequent NO production, and concurrently exerted an anti-adhesive effect as manifested by reduced endothelial P-selectin and ICAM-1 surface expression and PMNs adherence (13.7 ± 1.3% vs. 22.2 ± 1.9% in vehicle, n = 9, P < 0.01), all of which are abolished by the specific Akt inhibitor. Furthermore, inhibition of insulin-stimulated NO production using either the selective eNOS inhibitor cavtratin or the NOS inhibitor L-NAME blocked the anti-adhesive effect of insulin. These results demonstrate that insulin reduces endothelial P-selectin and ICAM-1 expression, and thus inhibits leukocyte–endothelium adherence in MI/R rabbit hearts. The anti-adhesive property by insulin may be mediated by the Akt-mediated and NO-dependent pathway.

Cigarette smoke extract induces expression of cell adhesion molecules in HUVEC via actin filament reorganization

Epidemiologic studies have shown a strong association between cigarette smoking and cardiovascular diseases. Various oxidative species and free radicals are produced during cigarette smoking and these lead to endothelial dysfunction and inflammation. Expression of adhesion molecules, such as intercellular adhesion molecule-1 (ICAM-1), E-selectin, and vascular cell adhesion molecule-1, and adhesion of leukocytes are present in atherosclerosis. We showed previously that a nonfractionated cigarette smoke extract (CSE) induces surface expression of ICAM-1 and E-selectin in human umbilical vein endothelial cells (HUVEC). We then investigated the role of the MAPKs (ERK1/2, JNK, and p38) and AP-1 and the role of actin cytoskeleton reorganization in the CSE-induced expression of ICAM-1 and E-selectin. Western blot analysis showed that CSE treatment rapidly and significantly caused phosphorylation of JNK and ERK1/2 but not of p38. Cytochalasin D (an actin filament disruptor) partially inhibited CSE-induced ICAM-1 and E-selectin surface expression. However, inhibitors of ERK1/2 (PD98059) and JNK (SP600125) did not attenuate the CSE-induced ICAM-1 and E-selectin surface expression. The results of electrophoretic mobility shift assay showed that CSE enhanced AP-1 binding activity. Therefore, CSE activated AP-1 and upregulated ICAM-1 and E-selectin surface expression in HUVEC seem to be via an MAPK-independent pathway. Moreover, the dynamic reorganization of the actin cytoskeleton seems to be required for the CSE-induced surface expression of ICAM-1 and E-selectin.

Cardiotrophin-1 induces intercellular adhesion molecule-1 expression by nuclear factor κB activation in human umbilical vein endothelial cells

In addition to elevated concentrations of cytokines, patients with congestive heart failure (CHF) show endothelial dysfunction and increased plasma concentrations of adhesion molecules like intercellular adhesion molecule-1 (ICAM-1). Furthermore, the concentration of cardiotrophin-1 (CT-1)--a cytokine of the interleukin-6 superfamily--is increased in CHF. We tested the hypothesis whether CT-1 is able to induce ICAM-1 in human umbilical vein endothelial cells (HUVEC). Furthermore we examined the signalling mechanisms of CT-1 mediated ICAM-1 expression. Confluent layers of HUVEC were incubated with increasing concentrations of CT-1 (5 to 100 ng/ml) for different periods. ICAM-1 mRNA was determined by real-time polymerase chain reaction (PCR) and ICAM-1 surface expression by fluorescence-activated cell sorter (FACS) analysis and soluble ICAM-1 (sICAM-1) in the culture supernatant by enzyme linked immunosorbent assay (ELISA). To clarify the signalling pathway of CT-1 induced ICAM-1 expression we used various inhibitors of possible signal transducing molecules, electromobility shift assay (EMSA) and Western blot analysis. CT-1 induced ICAM-1 mRNA (1.8 +/- 0.8 fold increase compared to unstimulated cells after 6 hours) and protein (1.4 +/- 0.2 fold increase compared to unstimulated cells after 48 hours) in HUVEC in a time- and concentration-dependent manner. EMSA experiments show that CT-1 causes nuclear factor (NF) kappaB activation. Because parthenolide could inhibit CT-1 induced ICAM-1 expression NFkappaB activation is required in this pathway. CT-1 did not activate extracellular signal regulated kinases (ERK), c-Jun N-terminal kinase (JNK) and p38. CT-1 is able to induce ICAM-1 in endothelial cells by NFkappaB activation. These results may explain in part elevated ICAM-1 concentrations in patients with CHF and endothelial dysfunction.

Circulating intercellular adhesion molecule-1 (ICAM-1) in autoimmune liver disease and evidence for the production of ICAM-1 by cytokine-stimulated human hepatocytes.

A circulating form of the membrane-bound ICAM-1 (CD54), a ligand for lymphocyte function-associated antigen-1 (LFA-1), has recently been identified in normal human serum. In this study, serum levels of soluble ICAM-1 (sICAM-1) were determined by sandwich ELISA both in normal healthy individuals of both sexes and in subjects with autoimmune liver diseases. Patients with primary biliary cirrhosis (PBC), primary sclerosing cholangitis and chronic active hepatitis (autoimmune) showed significant elevations in sICAM-1 compared with normal healthy subjects. The median level in PBC was approximately seven-fold above normal. Significant elevations in sICAM-1 were also detected, however, in patients with inactive alcoholic cirrhosis, suggesting that impaired liver clearance might at least in part account for the increased serum levels seen in patients with autoimmune liver disease. In patients with PBC, sICAM-1 levels were related to summary assessment of disease severity (Child-Pugh classification) and correlated significantly with serum biochemical indices of liver function, including measures both of cholestasis and liver cell injury. In contrast, serum levels of E-selectin did not differ significantly from healthy controls. Although it has been suggested that peripheral blood mononuclear cells (PBMC) may be a source of sICAM-1, investigation of ICAM-1 gene expression by reverse transcriptase polymerase chain reaction revealed similar basal levels of ICAM-1 message in PBMC of normal individuals and those with active PBC. This suggests that PBMC may not be a significant source of sICAM-1 in this disease. Similar increases in ICAM-1 mRNA expression were found in cultured, concanavalin A (Con A)-stimulated lymphocytes of both PBC patients and controls. Significantly, stimulation of cultured, normal human hepatocytes with proinflammatory cytokines and endotoxin induced cell surface expression of ICAM-1 and the secretion/shedding of sICAM-1 into the hepatocyte culture medium. This new finding suggests that hepatocytes may be an important source of sICAM-1 in autoimmune and other chronic liver diseases. The possible role of sICAM-1 in inflammatory disorders remains to be determined.

IFN-gamma regulation of ICAM-1 receptors in bronchial epithelial cells: soluble ICAM–1 release inhibits human rhinovirus infection

BackgroundIntercellular adhesion molecule-1 (ICAM-1) is a critical target-docking molecule on epithelial cells for 90% of human rhinovirus (HRV) serotypes. Two forms of ICAM-1 exist, membranous (mICAM-1) and soluble (sICAM-1), both expressed by bronchial epithelial cells. Interferon-gamma (IFN-γ), a crucial Th-1 immuno-regulatory mediator, can modulate mICAM-1 expression; however its simultaneous effects on mICAM-1: sICAM-1 levels and their consequent outcome on cell infectivity have not been previously explored.MethodsPrimary normal human bronchial epithelial cells were pre-stimulated with IFN-γ (1 ng/ml for 24 h) and subsequently inoculated with HRV-14 or HRV-1b (TCID50 10 2.5). Epithelial surface ICAM-1 expression and soluble ICAM-1 release were measured at the protein and gene level by immunofluorescence and ELISA respectively; mRNA levels were semi-quantified using RT-PCR. Molecular mechanisms regulating ICAM-1 isoform expression and effects on epithelial cell infectivity were explored.ResultsIn IFN-γ-biased cells infected with HRV-14, but not HRV-1b, mICAM-1 expression is down-regulated, with simultaneous induction of sICAM-1 release. This differential effect on HRV-14 receptor isoforms appears to be related to a combination of decreased IFN-γ-induced JAK-STAT signalling and proteolytic receptor cleavage of the membranous form in IFN-γ-biased HRV-14 infected cells. The observed changes in relative mICAM-1: sICAM-1 expression levels are associated with reduced HRV-14 viral titres.ConclusionThese findings support the hypothesis that in epithelial cells conditioned to IFN-γ and subsequently exposed to HRV-14 infection, differential modulation in the ratio of ICAM-1 receptors prevails in favour of an anti-viral milieu, appearing to limit further target cell viral attachment and propagation.

Inflammatory Markers of Atherosclerosis Are Decreased after Moderate Consumption of Cava (Sparkling Wine) in Men with Low Cardiovascular Risk ,

Atherosclerosis is considered a low-grade inflammatory disease. Polyphenol-rich alcoholic beverages (red wine) have shown a more pronounced antiinflammatory effect than polyphenol-free alcoholic beverages (gin). However, no studies to our knowledge have evaluated the antiinflammatory effects of alcoholic beverages with medium-level polyphenol content such as cava (sparkling wine). We enrolled 20 healthy men (aged 34 ± 9 y) in a randomized crossover study to receive 30 g ethanol/d as cava or gin for 28 d. Before both interventions, subjects abstained from alcohol for 2 wk. Inflammatory biomarkers of atherosclerosis and expression of adhesion molecules on peripheral leukocytes were measured before and after each intervention. Likewise, dietary intake and exercise were also evaluated. Expression of lymphocyte function-associated antigen-1 (LFA-1), very late activation antigen-4 (VLA-4), Sialyl-Lewisx (SLex), and CD40 on monocytes decreased after cava intake (all P < 0.05), whereas only SLex was reduced after gin intake (P = 0.036). Circulating markers of atherosclerosis including vascular cell adhesion molecule-1, E-selectin, and P-selectin decreased after both interventions (all P < 0.05). High-sensitivity C-reactive protein, intercellular adhesion molecule-1 (ICAM-1), IL-6, monocyte chemoattractant protein-1 (MCP-1), and CD40L were diminished only after cava intake (all P < 0.05). The effects of cava on circulating CD40L, ICAM-1, and MCP-1, and monocyte surface expression of CD40, LFA-1, and VLA-4 were greater than those of gin (all P < 0.05). In conclusion, both cava and gin showed antiinflammatory properties; however, cava had a greater protective effect, probably due its polyphenol content.

Oncostatin M induces angiogenesis and cartilage degradation in rheumatoid arthritis synovial tissue and human cartilage cocultures

To investigate the role of oncostatin M (OSM) in cell adhesion, angiogenesis, and matrix degradation in rheumatoid arthritis (RA) synovial tissue and normal human cartilage. Human dermal microvascular endothelial cell (HDMEC) and RA synovial fibroblast (RASF) proliferation and intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1) expression were assessed by a bromodeoxyuridine proliferation assay and flow cytometry. HDMEC tubule formation and migration were assessed by Matrigel culture and migration assay. Production of matrix metalloproteinase (MMP) and tissue inhibitor of metalloproteinases 1 (TIMP-1) in RA synovial explants, and proteoglycan/glycosaminoglycan (GAG) release, vascular endothelial growth factor (VEGF), and angiopoietin 2 production from RASF/normal cartilage cocultures were assessed by enzyme-linked immunosorbent assay and immunohistology. HDMEC/RASF proliferation was induced by OSM and interleukin-1beta (IL-1beta), alone and in combination. OSM enhanced cell surface expression of ICAM-1, but not VCAM-1, on endothelial cells and RASFs. OSM increased endothelial cell tubule formation and migration. In RA synovial explants, OSM induced production of MMP-1 and TIMP-1. When OSM was combined with IL-1beta, however, the MMP-1:TIMP-1 ratio was significantly increased. OSM potentiated IL-1beta-induced MMP-1 and MMP-13 expression in normal human cartilage/RASF cocultures, resulting in a significant increase in the MMP:TIMP ratio. In OSM/IL-1beta- stimulated cocultures, cartilage sections demonstrated significant proteoglycan depletion that was paralleled by a significant increase in GAG release in supernatants. Finally, compared with either cytokine alone, the combination of OSM and IL-1beta significantly induced VEGF production in RASF/cartilage cocultures. These data suggest that OSM promotes angiogenesis and endothelial cell migration and potentiates the effects of IL-1beta in promoting extracellular matrix turnover and human cartilage degradation. Furthermore, the induction of VEGF in cocultures supports the hypothesis of a link between angiogenesis and cartilage degradation.

Inhibition of ICAM-1 expression by garlic component, allicin, in gamma-irradiated human vascular endothelial cells via downregulation of the JNK signaling pathway

Ionizing radiation used in cancer therapy frequently exerts damaging effects on normal tissues and induces a complex response including inflammation. Since the upregulation of adhesion molecules on endothelial cell surface has been known to be associated with inflammation and our previous data showed that irradiation enhanced adhesion molecules expression, interfering with the expression of adhesion molecules may be an important therapeutic target of inflammatory diseases. We examined the effect of allicin, a major component of garlic, on the induction of intercellular adhesion molecule-1 (ICAM-1) by gamma-irradiation (γIR) and the mechanisms of its effect in gamma-irradiated human umbilical vein endothelial cells (HUVECs). HUVECs were pretreated for 20 h with allicin (0.01–1 μg/ml) and then exposed to 8 Gy radiation. Allicin significantly inhibited γIR-induced surface expression of ICAM-1 and ICAM mRNA in a dose-dependent manner. In addition, pretreatment with allicin resulted in the decrease of AP-1 activation and phosphorylation of the c-Jun NH2-terminal kinase (JNK) induced by γIR. These results suggest that allicin downregulates γIR-induced ICAM-1 expression via inhibition of both AP-1 activation and the JNK pathway and may be considered in therapeutic strategies for the management of patients treated with radiation therapy.

Glabridin Suppresses Intercellular Adhesion Molecule-1 Expression in Tumor Necrosis Factor-α-Stimulated Human Umbilical Vein Endothelial Cells by Blocking Sphingosine Kinase Pathway: Implications of Akt, Extracellular Signal-Regulated Kinase, and Nuclear Factor-κB/Rel Signaling Pathways

(<i>R</i>)-4-(3,4-Dihydro-8,8-dimethyl)-2<i>H</i>,8<i>H</i>-benzo[1,2-<i>b</i>:3,4-<i>b</i>′] dipyran-3yl)-1,3-benzenediol (glabridin) is known to have anti-inflammatory, antimicrobial, and cardiovascular protective activities. In the present study, we report the inhibitory effect of glabridin on intercellular adhesion molecule-1 (ICAM-1) expression in tumor necrosis factor-α (TNF-α)-stimulated human umbilical vein endothelial cells (HUVECs). Glabridin inhibited THP-1 cell adhesion to HUVECs stimulated by TNF-α and cell surface expression of ICAM-1 in TNF-α-stimulated HUVECs. The mRNA expression of adhesion molecules, including ICAM-1, vascular cell adhesion molecule-1, and E-selectin, was also suppressed by glabridin. Further study demonstrated the inhibitory effect of glabridin on nuclear factor (NF)-κB/Rel DNA binding, inhibitory factor-κBα (IκBα), and IκBβ degradation, IκB kinase activation, and p65 nuclear translocation in TNF-α-stimulated HUVECs. Treatment of a variety of cell lines with glabridin revealed that inhibitory effect of glabridin on NF-κB/Rel activation is not cell type-specific, and both inducible and constitutive NF-κB/Rel activation was suppressed by glabridin treatment. Moreover, TNF-α-induced phosphorylation of Akt and extracellular signal-regulated kinase (ERK) was blocked by glabridin treatment in HUVECs. Glabridin also suppressed sphingosine-1-phosphate (S1P)-induced cell surface expression and mRNA expression of ICAM-1. Further study demonstrated that TNF-α-induced sphingosine kinase activity was inhibited by glabridin, and the inhibitory effect of glabridin on TNF-α-induced ICAM-1 expression was reversed by addition of exogenous S1P. Together, our results indicate that the inhibitory effect of glabridin on ICAM-1 expression might be mediated, at least in part, by inhibiting sphingosine kinase pathway and subsequent inhibition of signaling pathways, including Akt, ERK, and NF-κB/Rel signaling pathway.

Postprandial, but not postabsorptive low-density lipoproteins increase the expression of intercellular adhesion molecule-1 in human aortic endothelial cells

The magnitude of postprandial lipemia has been identified as independent risk factor for the development of coronary artery disease. To test the effect of postprandial versus postabsorptive low-density lipoproteins (LDL) on the expression of adhesion molecules, LDL were isolated from healthy subjects before and 4 h after ingestion of a standardized fatty test meal. We used flow cytometry and Northern blotting to quantify cell adhesion molecules in human aortic endothelial cells (HAEC). The adherence of leukocytes to HAEC was analyzed using a monocyte adhesion assay. Incubation of HAEC with postprandial, but not postabsorptive LDL induced a two-fold increase in the surface expression of intercellular adhesion molecule-1 (ICAM-1), but not of E-selectin or vascular cell adhesion molecule-1. In addition, increased amounts of ICAM-1 transcripts were found in HAEC treated with postprandial LDL. The adhesion of monocytes to HAEC was enhanced after pretreatment with postprandial, but not with postabsorptive LDL. We conclude that postprandial, but not postabsorptive LDL increase the surface expression of ICAM-1 in HAEC apparently by de novo protein synthesis leading to increased adhesion of monocytes. The upregulation of ICAM-1 by postprandial LDL may explain part of the proatherogenic effect of high postprandial lipemia.

Acute Tumor Necrosis Factor Alpha Signaling via NADPH Oxidase in Microvascular Endothelial Cells: Role of p47phox Phosphorylation and Binding to TRAF4

Tumor necrosis factor alpha (TNF-alpha) receptor-associated factors (TRAFs) play important roles in TNF-alpha signaling by interacting with downstream signaling molecules, e.g., mitogen-activated protein kinases (MAPKs). However, TNF-alpha also signals through reactive oxygen species (ROS)-dependent pathways. The interrelationship between these pathways is unclear; however, a recent study suggested that TRAF4 could bind to the NADPH oxidase subunit p47phox. Here, we investigated the potential interaction between p47phox phosphorylation and TRAF4 binding and their relative roles in acute TNF-alpha signaling. Exposure of human microvascular endothelial cells (HMEC-1) to TNF-alpha (100 U/ml; 1 to 60 min) induced rapid (within 5 min) p47phox phosphorylation. This was paralleled by a 2.7- +/- 0.5-fold increase in p47phox-TRAF4 association, membrane translocation of p47phox-TRAF4, a 2.3- +/- 0.4-fold increase in p47phox-p22phox complex formation, and a 3.2- +/- 0.2-fold increase in NADPH-dependent O2- production (all P < 0.05). TRAF4-p47phox binding was accompanied by a progressive increase in extracellular signal-regulated kinases 1 and 2 (ERK1/2) and p38(MAPK) activation, which was inhibited by an O2- scavenger, tiron. TRAF4 predominantly bound the phosphorylated form of p47phox, in a protein kinase C-dependent process. Knockdown of TRAF4 expression using siRNA had no effect on p47phox phosphorylation or binding to p22phox but inhibited TNF-alpha-induced ERK1/2 activation. In coronary microvascular EC from p47phox-/- mice, TNF-alpha-induced NADPH oxidase activation, ERK1/2 activation, and cell surface intercellular adhesion molecule 1 (ICAM-1) expression were all inhibited. Thus, both p47phox phosphorylation and TRAF4 are required for acute TNF-alpha signaling. The increased binding between p47phox and TRAF4 that occurs after p47phox phosphorylation could serve to spatially confine ROS generation from NADPH oxidase and subsequent MAPK activation and cell surface ICAM-1 expression in EC.

Extracts from cigarette smoke induce DNA damage and cell adhesion molecule expression through different pathways

Cigarette smoke is a major risk factor for human diseases, such as lung cancer and atherosclerosis. The present study was undertaken to investigate the effect of non-fractionated water-soluble cigarette smoke extract (NFWS CSE) on DNA damage and cellular adhesion molecule expression in human umbilical vein endothelial cells (HUVECs). DNA damage and the surface expression of intercellular adhesion molecule-1 (ICAM-1) and E-selectin were determined by the use of the comet assay and flow cytometry, respectively. NFWS CSE-induced DNA damage in a dose-dependent manner during a 2 h exposure. Pretreatment with ascorbic acid or α-tocopherol completely inhibited the NFWS CSE-induced DNA damage. NFWS CSE exposure also up-regulated the surface expression of ICAM-1 and E-selectin in HUVECs. Pretreatment with ascorbic acid or α-tocopherol had no effect on NFWS CSE-induced E-selectin and ICAM-1 expression. In contrast, the non-antioxidant metal chelator 1,10-phenanthroline partially suppressed the surface expression of ICAM-1 and E-selectin. These results suggest that NFWS CSE exposure induces both DNA damage and the surface expression of adhesion molecules in HUVECs. However, the molecular mechanism of these effects may be through different pathways: reactive oxygen species are involved in NFWS CSE-induced DNA damage but have little relation to NFWS CSE-induced E-selectin and ICAM-1 expression.

Novel Role for Decay-Accelerating Factor in Coxsackievirus A21-Mediated Cell Infectivity

Decay-accelerating factor (DAF) is involved in the cell membrane attachment of many human enteroviruses. Presently, further specific active roles of DAF in mediating productive cell infection and in the pathogenesis of natural enterovirus infection are poorly understood. In an attempt to more fully understand the role of DAF in lytic cell infection we examined the specific interactions of the prototype strain of coxsackievirus A21 (CVA21) with surface-expressed DAF. Investigations into discrete DAF-CVA21 interactions focused on viral binding; viral particle elution with respect to the parameters of time, temperature, and pH; and subsequent cell infection. Radiolabeled-virus binding assays revealed that peak elution of CVA21 from DAF occurred within 15 min of initial attachment and that the DAF-eluted virus increased in a linear fashion with respect to temperature and pH. CVA21 eluted from endogenous surface-expressed DAF was highly infectious, in contrast to CVA21 eluted from intercellular adhesion molecule 1 (ICAM-1), which retained little to no infectivity. Using an adenovirus transduction system, we demonstrate that CVA21 can remain infectious for up to 24 h after DAF binding and is capable of initiating a multicycle lytic infection upon delayed ICAM-1 surface expression. Taken together, the data suggest that a major role of DAF in cell infection by the prototype strain of CVA21 is to provide membrane concentration of infectious virions, effectively increasing viral interactions with endogenous or induced ICAM-1.

Effect of glucocorticosteroids on tumour necrosis factor-alpha-induced intercellular adhesion molecule-1 expression in cultured primary human nasal epithelial cells.

In order to confirm the direct effect of glucocorticosteroids on epithelial intercellular adhesion molecule-1 (ICAM-1) expression, we examined ICAM-1 expression on primary cultured human nasal epithelial cells (HNECs) at both protein and mRNA levels. HNECs were stimulated with recombinant human TNF-alpha (20 pg/mL-20 ng/mL) for specified time periods (0, 12, 24, and 48 h) and ICAM-1 mRNA and the soluble ICAM-1 (sICAM-1) concentrations were measured by quantitative RT-PCR and ELISA, respectively. We also evaluated surface expression of ICAM-1 by flow cytometry 48 h after stimulation and determined the effect of dexamethasone (DEX) on TNF-alpha-induced ICAM-1 expression. Significant increases in ICAM-1 gene expression in HNECs were initially detected at 24 h, peaking at 48 h after the stimulation. The TNF-mediated-ICAM-1 mRNA and ICAM-1 surface expression at 48 h was significantly inhibited by co-incubation with human recombinant soluble TNF receptor I. Similarly, TNF-alpha-induced release sICAM-1 occurred in a time- and concentration-dependent manner. DEX 10(-6) M attenuated the TNF-alpha-induced ICAM-1 expression at mRNA and protein levels. Our finding suggests a potential role for topical steroids in allergic rhinitis in suppressing inflammatory reactions in the nasal mucosa by regulating ICAM-1 expression on nasal epithelium.

Effects of antioxidants and nitric oxide on TNF-α-induced adhesion molecule expression and NF-κB activation in human dermal microvascular endothelial cells

Cell adhesion molecules expressed on endothelial cells in inflamed skin appear to be controlled by the actions of cytokines and reactive oxygen species. However, molecular mechanisms of the expression of adhesion molecules during skin inflammation are currently not well understood. To evaluate the role of antioxidants and nitric oxide in modulating inflammatory processes in the skin, we examined the effects of pyrrolidine dithiocarbamate (PDTC, 0.1 mM) and spermine NONOate (Sper-NO, 1 mM) on adhesion molecule expression and nuclear factor kappa B (NF-κB) activation induced by TNF-α (10 ng/ml) in cultured human dermal microvascular endothelial cells (HDMEC). Treatment of cells with TNF-α for 4 h significantly induced the surface expression of E-selectin and intercellular adhesion molecule-1 (ICAM-1). Treatment with TNF-α for 8 h significantly induced the surface expression of E-selectin, ICAM-1 and vascular cell adhesion molecule-1 (VCAM-1). The up-regulation of these adhesion molecules was suppressed significantly by pretreatment with PDTC or Sper-NO for 1 h. The mRNA expression of E-selectin, ICAM-1 and VCAM-1, and activation of NF-κB induced by TNF-α for 2 h were significantly decreased by the above two pretreatments. N-acetylcysteine (10 mM) and S-nitroso-N-acetylpenicillamine (1 mM) had no significant inhibitory effects on the cell surface and mRNA expression of these adhesion molecules stimulated by TNF-α. These findings indicate that both cell surface and mRNA expression of adhesion molecules in HDMEC induced by TNF-α are inhibited significantly by pretreatment with PDTC or Sper-NO, possibly in part through blocking the activation of NF-κB. These results suggest a potential therapeutic approach using antioxidant agents or nitric oxide pathway modulators in the treatment of inflammatory skin diseases.

The role of the cytoskeleton in cellular adhesion molecule expression in tumor necrosis factor-stimulated endothelial cells.

Leukocyte infiltration is a hallmark of the atherosclerotic lesion. These cells are captured by cellular adhesion molecules (CAMs), including vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1), platelet-endothelial cell adhesion molecule (PECAM), and E-selectin, on endothelial cells (EC). We examined the role of the actin cytoskeleton in tumor necrosis factor-alpha (TNF-alpha)-induced translocation of CAMs to the cell surface. Human aortic EC were grown on 96-well plates and an ELISA was used to assess surface expression of the CAMs. TNF-alpha increased VCAM-1, ICAM-1, and E-selectin by 4 h but had no affect on the expression of PECAM. A functioning actin cytoskeleton was important for VCAM-1 and ICAM-1 expression as both cytochalasin D, an actin filament disruptor, and jasplakinolide, an actin filament stabilizer, attenuated the expression of these CAMs. These compounds were ineffective in altering E-selectin surface expression. Myosin light chains are phosphorylated in response to TNF-alpha and this appears to be regulated by Rho kinase instead of myosin light chain kinase. However, the Rho kinase inhibitor, Y27632, had no affect on TNF-alpha-induced CAM expression. ML-7, a myosin light chain kinase inhibitor, had a modest inhibitory effect on the translocation of VCAM-1 but not on ICAM-1 or E-selectin. These data suggest that the surface expression of VCAM-1 and ICAM-1 is dependent on cycling of the actin cytoskeleton. Nevertheless, modulation of actin filaments via myosin light chain phosphorylation is not necessary. The regulation of E-selectin surface expression differs from that of the other CAMs.