Ginsenoside Rb1 inhibits tumor necrosis factor-alpha-induced vascular cell adhesion molecule-1 expression in human endothelial cells.
ABSTRACT We investigated whether ginsenoside Rb1 (Rb1) could block tumor necrosis factor-alpha (TNF-alpha)-induced over-expression of vascular cell adhesion molecule-1 (VCAM-1) in human umbilical vein endothelial cells (HUVECs) and human lung microvascular endothelial cells (HMVECs-L). Cells were treated with various concentrations of TNF-alpha with or without Rb1 pre-treatment for 16 h. The mRNA and protein levels of VCAM-1 were determined with real-time polymerase chain reaction (PCR) and flow cytometry, respectively. Human monocytic THP-1 cells labeled with fluorescent dye (Calcein-AM) was used for the adhesion assay on HUVEC monolayers. Dihydroethidium (DHE) was used to demonstrate in situ levels of superoxide production. JC-1 dye was used to measure changes in mitochondrial membrane potential. Activation of mitogen-activated protein kinase (MAPK) and nuclear factor-kappaB (NF-kappaB) was determined by Bio-Plex immunoassay. TNF-alpha treatment significantly increased the mRNA and protein levels of VCAM-1 in HUVECs in a dose dependent manner. Rb1 pre-treatment effectively blocked the TNF-alpha-induced expression of VCAM-1 mRNA or protein by 80% and 43%, respectively (p<0.01). THP-1 adhesion was also blocked. Furthermore, Rb1 reduced the TNF-alpha-induced increase of superoxide anion production by 41% and inhibited the TNF-alpha-induced decrease of mitochondrial membrane potential by 44% in HUVECs. Rb1 also effectively blocked TNF-alpha-induced activation of p38, c-Jun N-terminal protein kinase, extracellular signal-regulated kinase 1/2 and IkappaBalpha. In conclusion, Rb1 effectively blocked the TNF-alpha-induced over-expression of VCAM-1, increased THP-1 adhesion and over-production of superoxide anion. Furthermore, Rb1 inhibited TNF-alpha-induced MAPKs and NF-kappaB activation. These data suggested that Rb1 might have potential therapeutic effects in controlling inflammation in vascular diseases.
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ABSTRACT: Monocyte adhesion to vascular endothelium has been reported to be one of the early processes in the development of atherosclerosis. In an attempt to develop strategies to prevent or delay atherosclerosis progression, we analyzed effects of the Wnt/beta-catenin signaling pathway on monocyte adhesion to various human endothelial cells. Adhesion of fluorescein-labeled monocytes to various human endothelial cells was analyzed under a fluorescent microscope. Unlike sodium chloride, lithium chloride enhanced monocyte adhesion to endothelial cells in a dose-dependent manner. We further demonstrated that inhibitors for glycogen synthase kinase (GSK)-3beta or proteosome enhanced monocyte-endothelial cell adhesion. Results of semi-quantitative reverse transcriptase polymerase chain reaction (RT-PCR) indicated that activation of Wnt/beta-catenin pathway did not change expression levels of mRNA for adhesion molecules. In conclusion, the canonical Wnt/beta-catenin pathway enhanced monocyte-endothelial cell adhesion without changing expression levels of adhesion molecules.Biochemical and Biophysical Research Communications 09/2006; 347(1):109-16. · 2.41 Impact Factor
- Critical Care Medicine 01/2006; 33(12 Suppl):S417-9. · 6.12 Impact Factor
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ABSTRACT: Endothelial cells actively participate in inflammatory events by regulating leukocyte recruitment via the expression of inflammatory genes such as E-selectin, VCAM-1, ICAM-1, IL-6, IL-8, and cyclooxygenase (COX)-2. In this study we showed by real-time RT-PCR that activation of human umbilical vein endothelial cells (HUVEC) by TNF-alpha and IL-1beta differentially affected the expression of these inflammatory genes. Combined treatment with TNF-alpha and IL-1beta resulted in nonadditive, additive, and even synergistic induction of expression of VCAM-1, IL-8, and IL-6, respectively. Overexpression of dominant-negative inhibitor kappaB protein blocking NF-kappaB signaling confirmed a major role of this pathway in controlling both TNF-alpha- and IL-1beta-induced expression of most of the genes studied. Although dexamethasone exerted limited effects at 1 muM, the thioredoxin inhibitor MOL-294, which regulates the redox state of NF-kappaB, mainly inhibited adhesion molecule expression. Its most pronounced effect was seen on VCAM-1 mRNA levels, especially in IL-1beta-activated endothelium. One micromolar RWJ-67657, an inhibitor of p38 MAPK activity, diminished TNF-alpha- and IL-1beta-induced expression of IL-6, IL-8, and E-selectin but had little effect on VCAM-1 and ICAM-1. Combined treatment of HUVEC with MOL-294 and RWJ-67657 resulted in significant blocking of the expression of E-selectin, IL-6, IL-8, and COX-2. The inhibitory effects were much stronger than those observed with single drug treatment. Application of combinations of drugs that affect multiple targets in activated endothelial cells may therefore be considered as a potential new therapeutic strategy to inhibit inflammatory disease activity.AJP Cell Physiology 12/2005; 289(5):C1229-39. · 3.71 Impact Factor