Vascular endothelial growth factor expression of intercellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1), and E-selectin through nuclear factor-kappa B activation in endothelial cells

Vascular endothelial growth factor (VEGF) induces adhesion molecules on endothelial cells during inflammation. Here we examined the mechanisms underlying VEGF-stimulated expression of intercellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1), and E-selectin in human umbilical vein endothelial cells. VEGF (20 ng/ml) increased expression of ICAM-1, VCAM-1, and E-selectin mRNAs in a time-dependent manner. These effects were significantly suppressed by Flk-1/kinase-insert domain containing receptor (KDR) antagonist and by inhibitors of phospholipase C, nuclear factor (NF)-kappaB, sphingosine kinase, and protein kinase C, but they were not affected by inhibitors of mitogen-activated protein/extracellular signal-regulated kinase kinase (MEK) 1/2 or nitric-oxide synthase. Unexpectedly, the phosphatidylinositol (PI) 3'-kinase inhibitor wortmannin enhanced both basal and VEGF-stimulated adhesion molecule expression, whereas insulin, a PI 3'-kinase activator, suppressed both basal and VEGF-stimulated expression. Gel shift analysis revealed that VEGF stimulated NF-kappaB activity. This effect was inhibited by phospholipase C, NF-kappaB, or protein kinase C inhibitor. VEGF increased VCAM-1 and ICAM-1 protein levels and increased leukocyte adhesiveness in a NF-kappaB-dependent manner. These results suggest that VEGF-stimulated expression of ICAM-1, VCAM-1, and E-selectin mRNAs was mainly through NF-kappaB activation with PI 3'-kinase-mediated suppression, but was independent of nitric oxide and MEK. Thus, VEGF simultaneously activates two signal transduction pathways that have opposite functions in the induction of adhesion molecule expression. The existence of parallel inverse signaling implies that the induction of adhesion molecule expression by VEGF is very finely regulated.     

HIV-1 Tat protein-induced VCAM-1 expression in human pulmonary artery endothelial cells and its signaling

Expression of cell adhesion molecule in endothelial cells upon activation by human immunodeficiency virus (HIV) infection is associated with the development of atherosclerotic vasculopathy. We postulated that induction of vascular cell adhesion molecule-1 (VCAM-1) by HIV-1 Tat protein in endothelial cells might represent an early event that could culminate in inflammatory cell recruitment and vascular injury. We determined the role of HIV-1 Tat protein in VCAM-1 expression in human pulmonary artery endothelial cells (HPAEC). HIV-1 Tat protein treatment significantly increased cell-surface expression of VCAM-1 in HPAEC. Consistently, mRNA expression of VCAM-1 was also increased by HIV-1 Tat protein as measured by RT-PCR. HIV-1 Tat protein-induced VCAM-1 expression was abolished by the NF-kappaB inhibitor pyrrolidine dithiocarbamate (PDTC) and the p38 MAPK inhibitor SB-203580. Furthermore, HIV-1 Tat protein enhanced DNA binding activity of NF-kappaB, facilitated nuclear translocation of NF-kappaB subunit p65, and increased production of reactive oxygen species (ROS). Similarly to VCAM-1 expression, HIV-1 Tat protein-induced NF-kappaB activation and ROS generation were abrogated by PDTC and SB-203580. These data indicate that HIV-1 Tat protein is able to induce VCAM-1 expression in HPAEC, which may represent a pivotal early molecular event in HIV-induced vascular/pulmonary injury. These data also suggest that the molecular mechanism underlying the HIV-1 Tat protein-induced VCAM-1 expression may involve ROS generation, p38 MAPK activation, and NF-kappaB translocation, which are the characteristics of pulmonary endothelial cell activation.     

Visfatin enhances ICAM-1 and VCAM-1 expression through ROS-dependent NF-kappaB activation in endothelial cells

Visfatin has recently been identified as a novel visceral adipokine which may be involved in obesity-related vascular disorders. However, it is not known whether visfatin directly contributes to endothelial dysfunction. Here, we investigated the effect of visfatin on vascular inflammation, a key step in a variety of vascular diseases. Visfatin induced leukocyte adhesion to endothelial cells and the aortic endothelium by induction of the cell adhesion molecules, ICAM-1 and VCAM-1. Promoter analysis revealed that visfatin-mediated induction of CAMs is mainly regulated by nuclear factor-kappaB (NF-kappaB). Visfatin stimulated IkappaBalpha phosphorylation, nuclear translocation of the p65 subunit of NF-kappaB, and NF-kappaB DNA binding activity in HMECs. Furthermore, visfatin increased ROS generation, and visfatin-induced CAMs expression and NF-kappaB activation were abrogated in the presence of the direct scavenger of ROS. Taken together, our results demonstrate that visfatin is a vascular inflammatory molecule that increases expression of the inflammatory CAMs, ICAM-1 and VCAM-1, through ROS-dependent NF-kappaB activation in endothelial cells.     

Suppression by 17beta-estradiol of monocyte adhesion to vascular endothelial cells is mediated by estrogen receptors

Several observational studies have shown that estrogen replacement therapy decreases cardiovascular mortality and morbidity in postmenopausal women. However, The Women's Health Initiative (WHI) study has found that women receiving estrogen plus progestin had a significantly higher risk of breast cancer, coronary heart disease, stroke, and pulmonary embolus. In the present study, we examined whether estrogen prevents mechanisms that relate to plaque formation by inhibiting monocyte adhesion to endothelial cells. ECV304 cells, an endothelial cell line that normally expresses minimal estrogen receptor (ER)alpha, were transfected with an ERalpha expression plasmid. Treatment with tumor necrosis factor (TNF)-alpha increased expression of vascular cell adhesion molecule (VCAM)-1 mRNA, activation of nuclear factor-kappaB (NF-kappaB), and U937 cell adhesion in ECV304 cells. These effects of TNF-alpha were not significantly inhibited by pretreatment of native ECV304 cells with 17beta-estradiol (E(2)). In ECV304 cells overexpressing ERalpha, E(2) significantly inhibited the effects of TNF-alpha on NF-kappaB activation, VCAM-1 expression, and U937 cell adhesion. These findings suggest E(2) suppresses inflammatory cell adhesion to vascular endothelial cells that possess functional estrogen receptors. The mechanism of suppression may involve inhibition of NF-kappaB-mediated up-regulation of VCAM-1 expression induced by atherogenic stimuli. E(2) may prevent plaque formation, as first stage of atheroscrelosis through inhibiting adhesion monocytes to endothelial cell. Actions of estrogen replacement therapy can be assessed in terms of densities of functional ERalpha.     

Simvastatin modulates TNFalpha-induced adhesion molecules expression in human endothelial cells

Adhesion and transendothelial migration of leukocytes into the vascular wall is a crucial step in atherogenesis. Expression of cell adhesion molecules by endothelial cells plays a leading role in this process. We investigated the effect of simvastatin, an inhibitor of HMG-CoA reductase administered to reduce plasma levels of LDL-cholesterol, on the expression of vascular cell adhesion molecule-1 (VCAM-1) and intracellular cell adhesion molecule-1 (ICAM-1) by human umbilical vein endothelial cells (HUVEC) stimulated with tumor necrosis factor alpha (TNFalpha). We found the expression to be significantly inhibited by the drug in a time and concentration-dependent manner and to a greater extent in the case of VCAM-1 as compared with ICAM-1. In TNFalpha-stimulated HUVEC, simvastatin decreased VCAM-1 and ICAM-1 mRNA levels, inhibited TNFalpha-induced activation of nuclear factor kappaB (NF-kappaB) and enhanced expression of peroxisome proliferator-activated receptor alpha (PPARalpha). These effects were associated with reduction of adherence of monocytes and lymphocytes to HUVEC. The present findings suggest that the benefits of statins in vascular disease may include the inhibition of expression of VCAM-1 and ICAM-1 through effects on NF-kappaB.     

Butyrate inhibits cytokine-induced VCAM-1 and ICAM-1 expression in cultured endothelial cells: the role of NF-kappaB and PPARalpha

Adhesion and migration of leukocytes into the surrounding tissues is a crucial step in inflammation, immunity, and atherogenesis. Expression of cell adhesion molecules by endothelial cells plays a leading role in this process. Butyrate, a natural short-chain fatty acid produced by bacterial fermentation of dietary fiber, has been attributed with anti-inflammatory activity in inflammatory bowel disease. Butyrate in vitro is active in colonocytes and several other cell types. We have studied the effect of butyrate on expression of endothelial leukocyte adhesion molecules by cytokine-stimulated human umbilical vein endothelial cells (HUVEC). Pretreatment of HUVEC with butyrate-inhibited tumor necrosis factor-alpha (TNFalpha)-induced expression of vascular cell adhesion molecule-1 (VCAM-1) and intracellular cell adhesion molecule-1 (ICAM-1) in a time and concentration-dependent manner. Butyrate at 10 mM/L inhibited interleukin-1 (IL-1)-stimulated VCAM-1 and ICAM-1 expression. The effect of butyrate on cytokine-stimulated VCAM-1 expression was more pronounced than in the case of ICAM-1. Butyrate decreased TNFalpha-induced expression of mRNA for VCAM-1 and ICAM-1. Suppressed expression of VCAM-1 and ICAM-1 was associated with reduced adherence of monocytes and lymphocytes to cytokine-stimulated HUVEC. Butyrate inhibited TNFalpha-induced activation of nuclear factor-kappaB (NF-kappaB) in HUVEC. Finally, butyrate enhanced peroxisome proliferator-activated receptor-alpha (PPARalpha) expression in HUVEC. These results demonstrate that butyrate may have anti-inflammatory properties not only in colonocytes but also in endothelial cells. The anti-inflammatory and (perhaps) antiatherogenic properties of butyrate may partly be attributed to an effect on activation of NF-kappaB and PPARalpha and to the associated expression of VCAM-1 and ICAM-1. The present findings support further investigations on the therapeutic benefits of butyrate in several pathological events involving leukocyte recruitment.     

The ascochlorin derivative, AS-6, inhibits TNF-alpha-induced adhesion molecule and chemokine expression in rat vascular smooth muscle cells

Vascular inflammation induced by the proinflammatory cytokine/NF-kappaB pathway is one of the key mechanisms in the development of atherosclerosis. Peroxisome proliferators-activated receptor-gamma (PPARgamma) plays an important role in the prevention of arterial inflammation and formation of atherogenesis. Herein we examine the effects of a newly identified synthetic PPARgamma ligand, ascochlorin-6 (AS-6), on TNF-alpha-stimulated NF-kappaB activity and inflammatory molecule expression in vascular smooth muscle cells (VSMCs). AS-6 successfully inhibited TNF-alpha-stimulated NF-kappaB activity and inflammatory molecule expression, including vascular cell adhesion molecule-1 (VCAM-1), monocyte chemotactic protein-1 (MCP-1), and fractalkine (CX3CL1). Transient transfection with an [NF-kappaB]x4 luciferase reporter construct showed that AS-6 inhibition of TNF-alpha-stimulated NF-kappaB activation was PPARgamma-dependent. The effects of AS-6 on TNF-alpha-stimulated VCAM-1 and CX3CL1 expression were abolished in cells transfected with an adenovirus expressing dominant-negative PPARgamma and in cells treated with a PPARgamma specific inhibitor, GW9662, confirming again that the anti-inflammatory effect of AS-6 was PPARgamma-dependent. The inhibitory effects of AS-6 on TNF-alpha-stimulated inflammatory gene expression and NF-kappaB activation were more potent than those of rosiglitazone and pioglitazone. This study shows that AS-6 reduces the inflammatory response to TNF-alpha in VSMCs. The data suggest the possibility that AS-6 can be used to prevent the development and progression of atherosclerosis.     

Globular adiponectin induces adhesion molecule expression through the sphingosine kinase pathway in vascular endothelial cells

The signaling pathways that couple adiponectin receptors to functional, particularly inflammatory, responses have remained elusive. We report here that globular adiponectin induces endothelial cell activation, as measured by the expression of adhesion proteins such as vascular adhesion molecule-1 (VCAM-1), intracellular adhesion molecule-1 (ICAM-1), E-selectin and MCP-1, through the sphingosine kinase (SKase) signaling pathway. Treatment of human umbilical vein endothelial cells with globular adiponectin resulted in NF-kappaB activation and increased mRNA levels of VCAM-1, ICAM-1, E-selectin and MCP-1. Sphingosine 1-phosphate (S1P), but not ceramide or sphingosine, was a potent stimulator of adhesion protein expression. As S1P is generated from sphingosine by SKase, we treated cells with siRNA for SKase to silence the effects of S1P in the endothelial cells. Treatment with SKase siRNA inhibited globular adiponectin-induced NF-kappaB activation and markedly decreased the globular adiponectin-induced mRNA levels of adhesion protein. Thus, we demonstrated that the SKase pathway, through the generation of S1P, is critically involved in mediating globular adiponectin-induced endothelial cell activation.     

Angiotensin II differentially regulates interleukin-1-beta-inducible NO synthase (iNOS) and vascular cell adhesion molecule-1 (VCAM-1) expression: role of p38 MAPK

Angiotensin II is implicated in pathophysiological processes associated with vascular injury and repair, which include regulating the expression of numerous NF-kappaB-dependent genes. The present study examined the effect of angiotensin II on interleukin-1beta-induced NF-kappaB activation and the subsequent expression of inducible NO synthase (iNOS) and vascular cell adhesion molecule-1 (VCAM-1) in cultured rat vascular smooth muscle cells. Neither NF-kappaB activation nor iNOS or VCAM-1 expression was induced in cells treated with angiotensin II alone. However, when added together with interleukin-1beta, angiotensin II, through activation of the AT(1) receptor, inhibited iNOS expression and enhanced VCAM-1 expression induced by the cytokine. The inhibitory effect of angiotensin II on iNOS expression was associated with a down-regulation of the sustained activation of extracellular signal-regulated kinase (ERK) and NF-kappaB by interleukin-1beta, whereas the effect on VCAM-1 was independent of ERK activation. The effect of angiotensin II on iNOS was abolished by inhibition of p38 mitogen-activated protein kinase (MAPK) with SB203580, but not by inhibition of PI3 kinase with wortmannin or stress-activated protein kinase/c-Jun NH(2)-terminal kinase (JNK) with JNK inhibitor II. Thus, angiotensin II, by a mechanism that requires the participation of p38 MAPK, differentially regulates the expression of NF-kappaB-dependent genes in response to interleukin-1beta stimulation by controlling the duration of activation of ERK and NF-kappaB.