TNFα-induced Adhesion Research Articles

MicroRNA-29a-3p Reduces TNFα-Induced Endothelial Dysfunction by Targeting Tumor Necrosis Factor Receptor 1

miR-29a-3p has been shown to be associated with cardiovascular diseases; however, the effect of miR-29a-3p on endothelial dysfunction is unclear. This study aimed to reveal the effects and mechanisms of miR-29a-3p on endothelial dysfunction. The levels of vascular cell adhesion molecule 1 (VCAM-1), intercellular adhesion molecule 1 (ICAM-1), and E-selectin were determined by real-time PCR and immunofluorescence staining to reveal the degree of tumor necrosis factor alpha (TNFα)-induced endothelial dysfunction. A luciferase activity assay and cell transfection with a miR-29a-3p mimic or an inhibitor were used to reveal the underlying mechanisms of miR-29a-3p action. Furthermore, the effects of miR-29a-3p on endothelial dysfunction were assessed in C57BL/6 mice injected with TNFα and/or a miR-29a-3p agomir. The results showed that the expression of TNFα-induced adhesion molecules in vascular endothelial cells (EA.hy926 cells, human aortic endothelial cells [HAECs], and primary human umbilical vein endothelial cells [pHUVECs]) and smooth muscle cells (human umbilical vein smooth muscle cells [HUVSMCs]) was significantly decreased following transfection with miR-29a-3p. This effect was reversed by cotransfection with a miR-29a-3p inhibitor. As a key target of miR-29a-3p, tumor necrosis factor receptor 1 mediated the effect of miR-29a-3p. Moreover, miR-29a-3p decreased the plasma levels of TNFα-induced VCAM-1 (32.62%), ICAM-1 (38.22%), and E-selectin (39.32%) in vivo. These data indicate that miR-29a-3p plays a protective role in TNFα-induced endothelial dysfunction, suggesting that miR-29a-3p is a novel target for the prevention and treatment of atherosclerosis.

Pharmacological inhibition of MALT1 protease activity suppresses endothelial activation via enhancing MCPIP1 expression

Mucosa associated lymphoid tissue lymphoma translocation protein 1 (MALT1) is not only an intracellular signaling scaffold protein but also a paracaspase that plays a key role in the signal transduction and cellular activation of lymphocytes and macrophages. However, its role in endothelial cells remains unknown. Here we report that pharmacological inhibition of MALT1 protease activity strongly suppresses endothelial activation via enhancing MCPIP1 expression. Treatment with MALT1 protease inhibitors selectively inhibited TNFα-induced VCAM-1 expression in HUVECs and LPS-induced VCAM-1 expression in mice. In addition, Inhibition of MALT1 protease activity also significantly inhibited TNFα-induced adhesion of THP-1 monocytic cells to HUVECs. To explore the mechanisms, MALT1 inhibitors does not affect the activation of NF-κB signaling pathway in HUVEC. However, they can stabilize MCPIP1 protein and significantly enhance MCPIP1 protein level in endothelial cells. These results suggest that MALT1 paracaspase also targets MCPIP1 and degrade MCPIP1 protein in endothelial cells similar as it does in immune cells. Taken together, the study suggest inhibition of MALT1 protease activity may represent a new strategy for prevention/therapy of vascular inflammatory diseases such as atherosclerosis.

C1q/TNF-related protein-9 inhibits cytokine-induced vascular inflammation and leukocyte adhesiveness via AMP-activated protein kinase activation in endothelial cells

Although recent studies have reported cardioprotective effects of C1q/TNF-related protein 9 (CTRP9), the closet adiponectin paralog, its role on cytokine-induced endothelial inflammation is unknown. We investigated whether CTRP9 prevented inflammatory cytokine-induced nuclear factor-kappa B (NF-κB) activation and inhibited the expression of adhesion molecules and a chemokine in the vascular endothelial cell. We used human aortic endothelial cells (HAECs) to examine the effects of CTRP9 on NF-κB activation and the expression of NF-κB-mediated genes, including intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and monocyte chemoattractant protein-1 (MCP-1). Tumor necrosis factor alpha (TNFα) was used as a representative proinflammatory cytokine. In an adhesion assay using THP-1 cells, CTRP9 reduced TNFα-induced adhesion of monocytes to HAECs. Treatment with CTRP9 significantly decreased TNFα-induced activation of NF-κB, as well as the expression of ICAM-1, VCAM-1, and MCP-1. In addition, treatment with CTRP9 significantly increased the phosphorylation of AMP-activated protein kinase (AMPK) and acetyl-CoA carboxylase (ACC), the downstream target of AMPK. The inhibitory effect of CTRP9 on the expression of ICAM-1, VCAM-1, and MCP-1 and monocyte adhesion to HAECs was abolished after transfection with an AMPKα1-specific siRNA. Our study is the first to demonstrate that CTRP9 attenuates cytokine-induced vascular inflammation in endothelial cells mediated by AMPK activation.

Vaspin inhibits cytokine-induced nuclear factor-kappa B activation and adhesion molecule expression via AMP-activated protein kinase activation in vascular endothelial cells

BackgroundVaspin is an adipocytokine that was recently identified in the visceral adipose tissue of diabetic rats and has anti-diabetic and anti-atherogenic effects. We hypothesized that vaspin prevents inflammatory cytokine-induced nuclear factor-kappa B (NF-κB) activation by activating AMP-activated protein kinase (AMPK) in vascular endothelial cells.MethodsWe examined the effects of vaspin on NF-κB activation and the expression of the NF-κB-mediated genes intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), E-selectin, and monocyte chemoattractant protein-1 (MCP-1). Human aortic endothelial cells (HAECS) were used. Tumor necrosis factor alpha (TNFα) was used as a representative proinflammatory cytokine.ResultsTreatment with vaspin significantly increased the phosphorylation of AMPK and acetyl-CoA carboxylase, the down-stream target of AMPK. Furthermore, treatment with vaspin significantly decreased TNFα-induced activation of NF-κB, as well as the expression of the adhesion molecules ICAM-1, VCAM-1, E-selectin, and MCP-1. These effects were abolished following transfection of AMPKα1-specific small interfering RNA. In an adhesion assay using THP-1 cells, vaspin reduced TNFα-induced adhesion of monocytes to HAECS in an AMPK-dependent manner.ConclusionsVaspin might attenuate the cytokine-induced expression of adhesion molecule genes by inhibiting NF-κB following AMPK activation.

Abstract 417: AT2R Stimulation Prevents TNFa-Induced Vascular Inflammation In Vitro and Ex Vivo

Vascular inflammation, involving the recruitment, adhesion and infiltration of monocytes to the sub-endothelial space, is a critical early event in the development of atherosclerosis. The renin angiotensin system plays an important role in inflammation via activation of the angiotensin type I receptor (AT1R), which induces pro-inflammatory effects. The angiotensin II type 2 receptor (AT2R) counter-regulates the effects of the AT1R, including AT1R-mediated pro-inflammatory cytokine expression. We investigated the anti-inflammatory effects of AT2R stimulation in vascular inflammation by examining leukocyte to endothelial adhesion. We quantified the effect of AT2R stimulation (Compound 21: C21, 100μM) on TNFα (10ng/mL)-induced monocyte adhesion to cultured human umbilical vascular endothelial cells in vitro . AT2R stimulation attenuated TNFα-induced monocyte adhesion (unstimulated: 8±4% of TNFα: 100%, C21+TNFα: 59±12% of TNFα-induced adhesion). Adhesion of monocytes to the endothelial monolayer following incubation with TNFα+C21+AT2R antagonism (PD 123319, 10μM) was not different to TNFα-induced monocyte adhesion (93±5% of TNFα); demonstrating that the anti-inflammatory effects of C21 are mediated by the AT2R. Furthermore, C21 treatment attenuated TNFα-induced upregulation of adhesion molecules ICAM-1 and E-selectin and abolished TNFα-induced ROS production (unstimulated: 2±2, TNFα: 55±16, TNFα+C21: -3±5 dihydroethidium fluorescence intensity units). We quantified TNFα-induced leukocyte adhesion in intact mouse thoracic aorta ex vivo in real time in the presence and absence of AT2R activation. Consistent with our in vitro findings, we observed that direct AT2R activation (C21, 10μM) abolished TNFα-induced leukocyte adhesion (TNFα: 30±4, vs TNFα+C21: 11±4 adhered leukocytes/field of view (FOV), P<0.01) an effect which was abolished by co-incubation with PD 123319 (10μM: 31±5 adhered leukocytes/FOV). This study provides the first functional evidence that direct AT2R stimulation prevents TNFα-induced leukocyte adhesion, ICAM-1 and E-selectin expression and ROS production revealing the anti-inflammatory and therapeutic potential of the AT2R in the treatment of inflammation-induced cardiovascular disease.

Astragalus polysaccharides suppress ICAM-1 and VCAM-1 expression in TNF-α-treated human vascular endothelial cells by blocking NF-κB activation

To investigate the effects Astragalus polysaccharides (APS) on tumor necrosis factor (TNF)-α-induced inflammatory reactions in human umbilical vein endothelial cells (HUVECs) and to elucidate the underlying mechanisms. HUVECs were treated with TNF-α for 24 h. The amounts of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) were determined with Western blotting. HUVEC viability and apoptosis were detected using cell viability assay and Hoechst staining, respectively. Reactive oxygen species (ROS) production was measured by DHE staining. Monocyte and HUVEC adhesion assay was used to detect endothelial cell adhesive function. NF-κB activation was detected with immunofluorescence. TNF-α (1-80 ng/mL) caused dose- and time-dependent increases of ICAM-1 and VCAM-1 expression in HUVECs, accompanied by significant augmentation of IκB phosphorylation and NF-κB translocation into the nuclei. Pretreatment with APS (10 and 50 μg/mL) significantly attenuated TNFα-induced upregulation of ICAM-1 VCAM-1 and NF-κB translocation. Moreover, APS significantly reduced apoptosis, ROS generation and adhesion function damage in TNF-α-treated HUVECs. APS suppresses TNFα-induced adhesion molecule expression by blocking NF-κB signaling and inhibiting ROS generation in HUVECs. The results suggest that APS may be used to treat and prevent endothelial cell injury-related diseases.

Reduced serum levels of vasostatin-2, an anti-inflammatory peptide derived from chromogranin A, are associated with the presence and severity of coronary artery disease

We here investigated the endothelial effects of the chromogranin A-derived peptide vasostatin-2 and its relation to coronary artery disease (CAD). We assessed the impact of recombinant vasostatin-1 and vasostatin-2 on tumour necrosis factor-alpha (TNFα)-, angiotensin II-, and oxidized low-density lipoprotein (oxLDL)-induced expression of adhesion molecules in human arterial endothelial cells. Vasostatin-1 and vasostatin-2 levels were examined in coronary endarterectomy specimens (n= 23), atherosclerotic aortas (n= 16), non-significant-atherosclerotic internal mammary arteries (n= 30), and non-atherosclerotic aortas (n= 10), as well as in peripheral blood mononuclear cells (PBMCs) from severe CAD patients (n= 50) and healthy volunteers (n= 21). Serum levels of vasostatin-2 were analysed in 968 consecutive patients undergoing coronary angiography. Vasostatin-1 and vasostatin-2 concentration-dependently inhibited TNFα-, angiotensin II-, and oxLDL-induced expression of adhesion molecules; and attenuated TNFα-induced adhesion of U937 monocytes to endothelial cells. Vasostatin-2 levels were significantly decreased in endarterectomy samples and atherosclerotic aortas compared with non-atherosclerotic internal mammary arteries and aortas, as well as in PBMCs of severe CAD patients compared with healthy controls (all P< 0.05). Serum vasostatin-2 levels were significantly lower in CAD patients (diameter stenosis ≥ 50%, n= 554) than in controls (normal arteries or diameter stenosis <30%, n= 281) (P< 0.001). Its concentrations correlated with the number of diseased coronary arteries and Syntax score in CAD patients (all P< 0.05). At multivariable regression analysis, decreased vasostatin-2 levels remained associated with CAD when other variables were taken into account. Vasostatin-2 has anti-inflammatory properties and is decreased in atherosclerotic plaque specimens and in PBMC of CAD patients. Decreased serum vasostatin-2 levels are associated with the presence and severity of CAD.

Suppression of endothelial cell activity by inhibition of TNFα

IntroductionTNFα is a proinflammatory cytokine that plays a central role in the pathogenesis of rheumatoid arthritis (RA). We investigated the effects of certolizumab pegol, a TNFα blocker, on endothelial cell function and angiogenesis.MethodsHuman dermal microvascular endothelial cells (HMVECs) were stimulated with TNFα with or without certolizumab pegol. TNFα-induced adhesion molecule expression and angiogenic chemokine secretion were measured by cell surface ELISA and angiogenic chemokine ELISA, respectively. We also examined the effect of certolizumab pegol on TNFα-induced myeloid human promyelocytic leukemia (HL-60) cell adhesion to HMVECs, as well as blood vessels in RA synovial tissue using the Stamper-Woodruff assay. Lastly, we performed HMVEC chemotaxis, and tube formation.ResultsCertolizumab pegol significantly blocked TNFα-induced HMVEC cell surface angiogenic E-selectin, vascular cell adhesion molecule-1 and intercellular adhesion molecule-1 expression and angiogenic chemokine secretion (P < 0.05). We found that certolizumab pegol significantly inhibited TNFα-induced HL-60 cell adhesion to HMVECs (P < 0.05), and blocked HL-60 cell adhesion to RA synovial tissue vasculature (P < 0.05). TNFα also enhanced HMVEC chemotaxis compared with the negative control group (P < 0.05) and this chemotactic response was significantly reduced by certolizumab pegol (P < 0.05). Certolizumab pegol inhibited TNFα-induced HMVEC tube formation on Matrigel (P < 0.05).ConclusionOur data support the hypothesis that certolizumab pegol inhibits TNFα-dependent leukocyte adhesion and angiogenesis, probably via inhibition of angiogenic adhesion molecule expression and angiogenic chemokine secretion.

Novel natural product-based cinnamates and their thio and thiono analogs as potent inhibitors of cell adhesion molecules on human endothelial cells

In the present study, we report the design and synthesis of novel analogs of cinnamates, thiocinnamates and thionocinnamates and evaluated the potencies of these analogs to inhibit TNF-α induced ICAM-1 expression on human endothelial cells. By using whole cell-ELISA, our screening data demonstrated that ethyl 3′,4′,5′-trimethoxythionocinnamate (ETMTC) is the most potent inhibitor of TNF-α induced ICAM-1, VCAM-1 and E-selectin. As functional consequences, ETMTC abrogated TNF-α induced adhesion of neutrophils to the endothelial monolayer. Structure–activity relationship studies revealed the critical role of the chain-length of the alkyl group in the alcohol moiety, number of methoxy groups in the aromatic ring of the cinnamoyl moiety and the presence of the α, β- C–C double bond in the thiocinnamates and thionocinnamates.

Inhibition of TNFα-induced adhesion molecule expression by (Z)-(S)-9-octadecenamide, N-(2-hydroxyethyl,1-methyl)

Inflammation is a primary event in atherogenesis. Oleoylethanolamide (OEA), a naturally occurring fatty-acid ethanolamide, lowers lipid levels in liver and blood through activation of the nuclear receptor, peroxisome proliferator-activated receptor-alpha (PPARα). We designed and synthesized (Z)-(S)-9-octadecenamide, N-(2-hydroxyethyl, 1-methyl) (OPA), an OEA analog. The present study investigated the effect of OPA on the expression of adhesion molecules in human umbilical vein endothelial cells (HUVEC). OPA inhibited expression of vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) stimulated by Tumor Necrosis Factor-α (TNF-α) via activation of PPARα. This inhibition of VCAM-1 and ICAM-1 expression decreased adhesion of monocyte-like cells to stimulated endothelial cells. These results demonstrate that OPA may have anti-inflammatory properties. Our results thus provide new insights into possible future therapeutic approaches to the treatment of atherosclerosis.

Translational Research Efforts in Biomarkers and Biology of Early Transplant-Related Complications

In the time since the first allogeneic hematopoietic stem cell transplantation (HSCT) was performed over 40 years ago, this life-saving procedure has been used increasingly for patients with hematologic, metabolic, and malignant diseases. Despite major advances in our understanding of the immunologic processes (both beneficial and injurious) that are associated with HSCT and improvements in supportive and critical care medicine, successful outcomes are still limited by several serious complications. As such, the establishment of effective therapeutic strategies for these complications will be crucial as increasing numbers of high-risk transplants are performed each year. The development of such approaches is fundamentally dependent upon a basic understanding of pathophysiologic mechanisms of disease and also on our ability to successfully translate these insights back to the bedside. This brief review will highlight breakthroughs in translational research endeavors that have paved the way for the development of novel strategies intended to change the standard of care and optimize outcomes for patients in whom allogeneic HSCT offers the only hope for a cure.

Dietary flavonoid apigenin inhibits high glucose and tumor necrosis factor α-induced adhesion molecule expression in human endothelial cells

Diabetes mellitus is associated with increased endothelial dysfunction and development of atherosclerotic vascular diseases. In contrast, an increased intake of dietary flavonoids is associated with a decreased risk of cardiovascular diseases. Here we demonstrate that high glucose (HG) and tumor necrosis factor α (TNFα) result in the expression of adhesion molecules and junctional molecules on endothelial cells (EC) within a short time. Simultaneously, we examined the regulatory effects of several dietary flavonoids. We demonstrated the short-term expression of adhesion molecules in a human EC line cultured with normal glucose (5.5 mM), HG (30 mM) and TNFα (10 ng/ml) by reverse transcription–polymerase chain reaction (RT-PCR), immunocytochemistry and adhesion assay. The expression of intercellular adhesion molecule-1 (ICAM1) and vascular cell adhesion molecule-1 (VCAM1) increased, but that of occludin decreased. Apigenin strongly inhibited the expression of VCAM1, IκB kinase (IKK) α and IKKɛ/IKKi, and suppressed the adhesion of U937 cells. From the structure and inhibitory activity of several dietary flavonoids, it was recognized that a double bond between apigenin and the third hydroxyl group was required for inhibition of gene expression. HG and TNFα induced the expression of cell adhesion molecules and reduced that of occludin in EC. These flavonoids modified the expression of cloudin 5 and occludin. These results demonstrated that apigenin inhibits HG- and TNFα-induced adhesion molecule expression and that flavonoids regulate the expression of junctional molecules in human EC. It is suggested that apigenin inhibited the expression of several genes through inhibition of IKKs.

P38 mitogen-activated kinase (MAPK) is essential for equine neutrophil migration

Equine laminar tissues do not contain resident neutrophils and have less superoxide dismutase (SOD) activity than other equine tissues, which makes them inherently more vulnerable to damage induced by reactive oxygen species (ROS) produced by neutrophils that enter the tissues. In the advanced clinical stages of acute laminitis, pathologic events in affected feet include a breakdown in the basement membrane, neutrophil infiltration, and platelet–neutrophil aggregates in laminar dermal veins, highlighting the contribution of neutrophils to the pathophysiology of the disease. The aim of this study was to determine the role of p38 MAPK in the mechanism underlying equine neutrophil migration to potentially reveal therapeutic targets that may limit lamellar damage from the neutrophil influx that occurs in acute laminitis. We determined that the endogenous chemoattractant LTB 4 transiently activated p38 MAPK and induced chemotaxis of equine primary neutrophils. Inhibition with the p38 MAPK specific inhibitor SB203580 reduced LTB 4-induced migration in a dose-dependent manner with an IC 50 of 2.8 μM. We then examined the potential mechanisms underlying the ability of SB203580 to abolish migration. We determined that inhibition of p38 MAPK with 10 μM SB203580 disrupted the ability of neutrophils to polarize in response to LTB 4 and PAF. In contrast, p38 MAPK did not appear to be required for chemoattractant- or PKC-induced β2 integrin-dependent adhesion or chemoattractant-induced upregulation of surface β2 integrins, but was required for TNFα-induced adhesion. These findings support a function for p38 MAPK in equine neutrophil migration and suggest the potential for the ability of p38 MAPK inhibition to limit neutrophilic inflammation in the laminae during acute laminitis.

Role of Scavenger Receptor Class B Type I and Sphingosine 1-Phosphate Receptors in High Density Lipoprotein-induced Inhibition of Adhesion Molecule Expression in Endothelial Cells

We characterized the molecular mechanisms by which high density lipoprotein (HDL) inhibits the expression of adhesion molecules, including vascular cell adhesion molecule-1 and intercellular adhesion molecule-1, induced by sphingosine 1-phosphate (S1P) and tumor necrosis factor (TNF) alpha in endothelial cells. HDL inhibited S1P-induced nuclear factor kappaB activation and adhesion molecule expression in human umbilical vein endothelial cells. The inhibitory HDL actions were associated with nitric-oxide synthase (NOS) activation and were reversed by inhibitors for phosphatidylinositol 3-kinase and NOS. The HDL-induced inhibitory actions were also attenuated by the down-regulation of scavenger receptor class B type I (SR-BI) and its associated protein PDZK1. When TNFalpha was used as a stimulant, the HDL-induced NOS activation and the inhibitory action on adhesion molecule expression were, in part, attenuated by the down-regulation of the expression of S1P receptors, especially S1P(1), in addition to SR-BI. Reconstituted HDL composed mainly of apolipoprotein A-I and phosphatidylcholine mimicked the SR-BI-sensitive part of HDL-induced actions. Down-regulation of S1P(3) receptors severely suppressed the stimulatory actions of S1P. Although G(i/o) proteins may play roles in either stimulatory or inhibitory S1P actions, as judged from pertussis toxin sensitivity, the coupling of S1P(3) receptors to G(12/13) proteins may be critical to distinguish the stimulatory pathways from the inhibitory ones. In conclusion, even though S1P alone stimulates adhesion molecule expression, HDL overcomes S1P(3) receptor-mediated stimulatory actions through SR-BI/PDZK1-mediated signaling pathways involving phosphatidylinositol 3-kinase and NOS. In addition, the S1P component of HDL plays a role in the inhibition of TNFalpha-induced actions through S1P receptors, especially S1P(1).

Normalizing the bone marrow microenvironment with p38 inhibitor reduces multiple myeloma cell proliferation and adhesion and suppresses osteoclast formation

The multiple myeloma (MM) bone marrow (BM) microenvironment plays a critical role in supporting tumor growth and survival as well as in promoting formation of osteolytic lesions. Recent results suggest that the p38 mitogen-activated protein kinase (MAPK) is an important factor in maintaining this activated environment. In this report, we demonstrate that the p38α MAPK inhibitor, SCIO-469, suppresses secretion of the tumor-supportive factors IL-6 and VEGF from BM stromal cells (BMSCs) as well as cocultures of BMSCs with MM cells, resulting in reduction in MM cell proliferation. Additionally, we show that SCIO-469 prevents TNFα-induced adhesion of MM cells to BMSCs through an ICAM-1- and VCAM-1-independent mechanism. Microarray analysis revealed a novel set of TNFα-induced chemokines in BMSCs that is strongly inhibited by SCIO-469. Furthermore, reintroduction of chemokines CXCL10 and CCL8 to BMSCs overcomes the inhibitory effect of SCIO-469 on TNFα-induced MM adhesion. Lastly, we show that SCIO-469 inhibits secretion and expression of the osteoclast-activating factors IL-11, RANKL, and MIP-1α as well as prevents human osteoclast formation in vitro. Collectively, these results suggest that SCIO-469 treatment can suppress factors in the bone marrow microenvironment to inhibit MM cell proliferation and adhesion and also to alleviate osteolytic activation in MM.

Conjugated linoleic acids have no effect on TNFα-induced adhesion molecule expression, U937 monocyte adhesion, and chemokine release in human aortic endothelial cells

Leukocyte recruitment and adhesion to the endothelium are critical steps in the early phase of atherosclerosis. Synthetic ligands of peroxisome proliferator-activated receptors (PPARs) were shown to reduce cytokine-stimulated leukocyte–endothelial cell interactions by inhibiting the NF-κB mediated inflammatory response. Conjugated linoleic acids (CLA), which are natural ligands of PPARs, were demonstrated to have anti-inflammatory and anti-atherogenic properties in vivo. With a view to elucidating the anti-atherogenic mechanisms of CLA, the present study aimed to explore the effects of cis-9, trans-11 CLA and trans-10, cis-12 CLA on cytokine-induced chemokine release, surface expression of adhesion molecules (ICAM-1, VCAM-1, and E-selectin) and U937 monocyte adhesion in human aortic endothelial cells (HAEC). Treatment of HAECs with 2 ng/mL of TNFα markedly increased expression of adhesion molecules, U937 monocyte adhesion, and release of the monocyte chemoattractant protein (MCP)-1. However, treatment of HAECs with either CLA isomer or linoleic acid did not modulate the cytokine-induced expression of ICAM-1, VCAM-1, and E-selectin, U937 cell adhesion and MCP-1 release. In addition, both CLA isomers and linoleic acid slightly increased PPARγ DNA-binding activity, but did not alter DNA-binding activity of NF-κB. In conclusion, CLA isomers showed no effect on cytokine-induced monocyte–endothelial cell interactions and on the molecular mechanisms regulating these processes in HAEC. This study suggests that anti-atherogenic effects of CLA observed in vivo are probably not mediated by reduced monocyte–endothelial cell interactions.

Simvastatin modulates TNFα-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 α (TNFα). 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 TNFα-stimulated HUVEC, simvastatin decreased VCAM-1 and ICAM-1 mRNA levels, inhibited TNFα-induced activation of nuclear factor κB (NF-κB) and enhanced expression of peroxisome proliferator-activated receptor α (PPARα). 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-κB.

Lack of inhibitory effect of HDL on TNFα-induced adhesion molecule expression in human aortic endothelial cells

Monocyte adhesion to and transmigration across the endothelium are initiating steps in atherogenesis. Cytokine-induced adhesion molecule expression in human umbilical vein endothelial cells (HUVEC) has been reported to be inhibited by either native HDL or reconstituted discoidal HDL (rHDL). In the present study we investigated these putative anti-atherosclerotic effects of HDL and rHDL in a more physiologically relevant cell type, i.e. human aortic endothelial cells (HAEC). HDL isolated by ultracentrifugation from eleven healthy subjects or rHDL made with apoA-I and either 1-palmitoyl-2-oleyl-sn-glycero-3-phosphocholine, 1-palmitoyl-2-linoleoyl-sn-glycero-3-phosphocholine (PLPC), or 1,2-dimyristoyl-sn-glycero-3-phosphocholine was incubated for 16 h with HAEC prior to stimulation with tumor necrosis factor-α (TNFα, 100 U/ml). Expression of E-selectin, vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) was measured by cell ELISA and Northern blot analysis. HDL (0.25, 0.5, 1.0 and 2.0 mg protein/ml) failed to significantly inhibit TNFα-induced mRNA and protein expression of all three adhesion molecules. Furthermore, of the three rHDL preparations (16 μmol/l apoA-I) only that containing the polyunsaturated PLPC significantly reduced TNFα-induced VCAM-1 expression (by 29.9±9.1%). These data contrast with previously reported results using plasma HDL and HUVEC, and show that human HDL and rHDL, except for PLPC-rHDL, are ineffective inhibitors of TNFα-induced adhesion molecule expression in HAEC. The ability of polyunsaturated phospholipids in HDL to affect endothelial activation remains to be further investigated.

Effect of tyrosine kinase inhibitors on TNFα-induced adhesion molecule expression on HUVE cells

Effect of tyrosine kinase inhibitors on TNFα-induced adhesion molecule expression on HUVE cells

Effect of tyrosine kinase inhibitors on TNFα-induced adhesion molecule expression on HUVE cells

Effect of tyrosine kinase inhibitors on TNFα-induced adhesion molecule expression on HUVE cells