Inhibitory effect of GSPE on RAGE expression induced by advanced glycation end products in endothelial cells

Advanced glycation end products' (AGEs) engagement of a cell-surface receptor for AGEs (RAGE) has been causally implicated in the pathogenesis of diabetic vascular complications via induction of reactive oxygen species (ROS) and subsequent alteration of many gene expressions, including RAGE itself. Grapeseed proanthocyanidin extract (GSPE), which is a naturally occurring polyphenolic compound, has been reported to possess potent radical-scavenging and antioxidant properties and to display significant cardiovascular protective action. In this study, we investigated whether GSPE could inhibit AGE-induced RAGE expression through interference with ROS generation in human umbilical-vein endothelial cells (HUVECs). AGE-modified bovine serum albumin (AGE-BSA) was prepared by incubating BSA with high-concentration glucose. Stimulation of cultured HUVECs with 200 microg/mL of AGE-BSA significantly enhanced intracellular ROS formation and subsequently upregulated the protein and mRNA expression of RAGE; unmodified BSA and GSPE alone had no effect. However, GSPE preincubation markedly downregulated AGE-induced surface expression of RAGE in a time- and concentration-dependent manner. In AGE-stimulated HUVECs, GSPE also dose-dependently decreased RAGE mRNA levels and inhibited AGE-induced ROS generation at defined time periods. These results demonstrate that GSPE can inhibit enhanced RAGE expression in AGE-exposed endothelial cells by suppressing ROS generation, thereby limiting the AGE-RAGE interaction. Hence, GSPE may have therapeutic potential in the prevention and treatment of vascular complications in diabetic patients.     

Selective inhibition by grape seed proanthocyanidin extracts of cell adhesion molecule expression induced by advanced glycation end products in endothelial cells

The interaction of advanced glycation end products (AGE) with their cell surface receptors for AGEs (RAGE) has been causally implicated in the pathogenesis of diabetic vascular complications and has been shown to stimulate cell adhesion molecule expression in endothelial cells via induction of reactive oxygen species (ROS). Alternatively, grape seed proanthocyanidin extracts (GSPE), which are naturally occurring polyphenolic compounds, have been reported to possess potent radical scavenging and antioxidant properties and to display significant cardiovascular protective action. In this study, we investigated whether GSPE could inhibit AGE-induced cell adhesion molecule expression through interference with ROS generations in human umbilical vein endothelial cells. AGE-modified bovine serum albumin (AGE-BSA) was prepared by incubating BSA with a high concentration of glucose. Stimulation of cultured human umbilical vein endothelial cells with 200 microg/mL of AGE-BSA significantly enhanced intracellular ROS formation and subsequently upregulated the expression of vascular cell adhesion molecule-1 (VCAM) and intercellular adhesion molecule-1 (ICAM-1), whereas both unmodified BSA and GSPE alone were without effect. However, preincubation of different concentrations of GSPE markedly downregulated AGE-BSA-induced VCAM-1 expression at the surface protein and mRNA level in a concentration-dependent manner, but the increased ICAM-1 expression was not affected by GSPE treatment. Meanwhile, the inhibition by GSPE of intracellular ROS generation was also observed at defined time periods. These results demonstrate that GSPE can inhibit the enhanced VCAM-1 expression but not ICAM-1 in AGE-exposed endothelial cells by suppressing ROS generation. Hence, GSPE may have therapeutic potential in the prevention and treatment of vascular complications in patients with diabetes.     

Nifedipine inhibits tumor necrosis factor-alpha-induced leukocyte adhesion to endothelial cells by suppressing vascular cell adhesion molecule-1 (VCAM-1) expression

We have previously shown that nifedipine, one of the most popular dihydropyridine-based calcium antagonists (DHPs), blocked tumor necrosis factor-alpha (TNF-alpha)-induced reactive oxygen species generation and subsequent monocyte chemoattractant protein-1 expression in endothelial cells (ECs), thus suggesting that nifedipine may inhibit monocyte recruitment, an initiating step in atherosclerosis. However, the effect of nifedipine on leukocyte adhesion to ECs, another pivotal step in the early stage of atherosclerosis, remains to be elucidated. In this study, we investigated whether nifedipine could inhibit TNF-alpha-induced vascular cell adhesion molecule-1 (VCAM-1) expression and subsequent leukocyte adhesion to human umbilical vein endothelial cells (HUVEC). Nifedipine significantly inhibited TNF-alpha-induced up-regulation of VCAM-1 mRNA levels in HUVEC. Furthermore, nifedipine was found to block MOLT-3 (a human lymphoblastic cell line) cell adhesion to TNF-alpha-exposed HUVEC. The results suggest that nifedipine could inhibit TNF-alpha-induced leukocyte adhesion to ECs by suppressing VCAM-1 expression. Our present study provides a novel beneficial aspect of nifedipine on atherogenesis.     

Blockade by nifedipine of advanced glycation end product-induced CD40-CD40 ligand interaction in endothelial cells

Advanced glycation end products (AGEs), the senescent macroprotein derivatives that form in increased amounts in diabetes, have been implicated in the pathogenesis of accelerated atherosclerosis. There is a growing body of evidence that CD40-CD40 ligand (CD40L) interaction also plays an important role in atherogenesis. However, the effects of AGEs on CD40-CD40L signaling in endothelial cells (ECs) remain to be elucidated. In this study, we investigated (i) whether injection of AGE-proteins to normal rats stimulates CD40L expression on circulating platelets and (ii) whether AGEs up-regulate CD40 mRNA levels in cultured ECs. We further examined the effects of nifedipine, one of the most popular dihydropyridine-based calcium antagonists, on CD40 gene expression in AGE-exposed ECs. Platelet surface CD40L expression was increased in AGE-bovine serum albumin (AGE-BSA)-injected rats, compared with nonglycated BSA administration. AGEs were found to induce up-regulation of CD40 mRNA levels in ECs, which were significantly blocked by nifedipine. These results suggest that AGEs could enhance CD40-CD40L interaction, thereby promoting atherosclerosis in diabetes. Blockade of CD40-CD40L signaling in ECs may be a molecular target for the vasculoprotective property of nifedipine.     

Nifedipine inhibits tumor necrosis factor-alpha-induced monocyte chemoattractant protein-1 overexpression by blocking NADPH oxidase-mediated reactive oxygen species generation

There is a growing body of evidence that dihydropyridine-based calcium antagonists (DHPs) improve endothelial function, thus slowing the development and progression of atherosclerosis. However the molecular mechanisms by which DHPs normalize endothelial dysfunction, an initial step in atherosclerosis, are not fully understood. Monocyte recruitment and firm adhesion to endothelial cells play a central role in the pathogenesis of atherosclerosis. In this study, we investigated whether nifedipine, one of the most popular DHPs, could inhibit tumor necrosis factor-alpha (TNF-alpha)-induced reactive oxygen species (ROS) generation and subsequent monocyte chemoattractant protein-1 (MCP-1) expression in human umbilical vein endothelial cells (HUVEC). TNF-alpha significantly increased intracellular ROS generation in HUVEC, which was completely blocked by nifedipine. Nifedipine completely inhibited TNF-alpha-induced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity in HUVEC. Furthermore, nifedipine was found to significantly inhibit upregulation of MCP-1 messenger RNA levels in TNF-alpha-exposed HUVEC. The results demonstrate that nifedipine could inhibit TNF-alpha-induced MCP-1 overexpression in HUVEC by suppressing NADPH oxidase-mediated ROS generation. Our present study suggests that nifedipine may play a protective role in the development and progression of atherosclerosis through its antioxidative properties.     

Grape seed proanthocyanidin extracts inhibit vascular cell adhesion molecule expression induced by advanced glycation end products through activation of peroxisome proliferators-activated receptor gamma

Although evidence has shown that grape seed proanthocyanidin extracts (GSPE) can selectively inhibit cell adhesion molecule expression induced by advanced glycation end products (AGEs), the underlying molecular mechanism has not been extensively characterized. To study the antiinflammation mechanism of GSPE, we investigated the effect of GSPE on Von Willebrand factor (vWF) content and the expression of vascular cell adhesion molecule-1 (VCAM-1) induced by AGEs and the effect of GSPE on peroxisome proliferators-activated receptor gamma (PPAR gamma) and receptor for AGEs (RAGE) expression in human umbilical vein endothelial cells (HUVEC). HUVEC were preincubated with or without GSPE of different concentrations (10 mg/L, 50 mg/L, and 100 mg/L) for 4 hours before being treated with 200 mg/L AGEs or unmodified bovine serum albumin (BSA) for 24 hours. The expression of RAGE and PPAR gamma was investigated by Western blot. VCAM-1 expression was measured by flow cytometry and vWF content by enzyme-linked immunosorbent assay (ELISA). Results showed that GSPE significantly inhibited the expression of VCAM-1 in HUVEC and reduced the content of vWF in culture fluid induced by AGEs in a dose-dependent manner. AGEs activated the expression of RAGE and inhibited PPAR gamma expression in HUVEC, whereas GSPE inhibited the expression of RAGE through activation of PPAR gamma in HUVEC simultaneously. These findings indicated that GSPE inhibited the cell inflammatory factor expression and protected the function of endothelial cell through activation of PPAR gamma expression and inhibition of RAGE expression.     

Receptor for advanced glycation end products (RAGE): a novel therapeutic target for diabetic vascular complication

Diabetic vascular complication is a leading cause of acquired blindness, end-stage renal failure, a variety of neuropathies and accelerated atherosclerosis, which could account for disabilities and high mortality rates in patients with diabetes. Although several hyperglycemia-elicited metabolic and hemodynamic derangements have been implicated in the pathogenesis of diabetic vascular complication, the process of formation and accumulation of advanced glycation end products (AGEs) and their mode of action are most compatible with the theory 'hyperglycemic memory'. Further, there is a growing body of evidence that AGEs and their receptor (RAGE) axis is involved in the pathogenesis of diabetic vascular complication. Indeed, the engagement of RAGE with AGEs is shown to elicit oxidative stress generation and subsequently evoke inflammatory responses in various types of cells, thus playing an important role in the development and progression of diabetic micro- and macroangiopathy. These observations suggest that down-regulation of RAGE expression or blockade of the RAGE downstream signaling may be a promising target for therapeutic intervention in diabetic vascular complication. In this review, we discuss several types of agents that could potentially inhibit RAGE expression or its downstream pathways and their therapeutic implications in diabetic vascular complication.     

Novel therapeutics for diabetic micro- and macrovascular complications

Diabetic patients have a two- to four-fold increased risk for the development of microvascular (renal, neuronal and retinal) and macrovascular complications. Unfortunately, these complications may develop in both Type 1 and Type 2 diabetic patients even with careful glycaemic, blood pressure and lipid control. With the worldwide increase in the incidence diabetes, new strategies to prevent the complications are urgently needed. Mediators of vascular damage of diabetes include poor glycemic control, lipoprotein abnormalities, hypertension, oxidative stress, inflammation and advanced glycation end-products (AGEs), which are modified proteins formed by non-enzymatic glycation. AGEs are resistant to enzymatic degradation and therefore very stable, thus their accumulation continues throughout aging. AGE accumulation causes arterial stiffening in the vessel wall, glomerulosclerosis in the kidney, and vascular hyperpermeability in the retina. Through their interaction with their putative receptor the so-called receptor for AGEs (RAGE), AGEs activate endothelial cells and macrophages, generate reactive oxygen species (ROS), induce overexpression of vascular endothelial growth factor (VEGF) and vascular cell adhesion molecule-1 (VCAM-1), and quench nitric oxide (NO). The pharmacological treatment currently available for either Type 1 or Type 2 diabetic patients does not directly address the excess accumulation of AGEs. Novel compounds that inhibit AGE formation, cleave AGE cross-links or reverse their interaction with RAGE are now accessible and could prove useful in meeting this challenge. Other strategies such as inhibition of the hexosamine pathway, vitamin therapy to reduce oxidation and AGE accumulation, reduction of the ROS, or blocking the actions of growth factors or intracellular messengers of cell differentiation are also currently under research. This review will recount recent advances in the development of therapeutic approaches for inhibiting and treating the development of diabetic end-organ damage.     

Inhibition by advanced glycation end products (AGEs) of pigment epithelium-derived factor (PEDF) gene expression in microvascular endothelial cells

Pigment epithelium-derived factor (PEDF) is a natural extracellular component of the retina with neuronal differentiating activity. Recently, decreased levels of PEDF in the mammalian eye have been shown to participate in the pathogenesis of diabetic retinopathy In addition, advanced glycation end products (AGEs), senescent macroprotein derivatives that form at an accelerated rate under diabetes, have also been implicated in the development and progression of diabetic retinopathy. However the role of AGEs in decreased levels of PEDF in the eye remains to be elucidated. In this study, we examined the effects of AGEs on PEDF gene expression in microvascular endothelial cells (ECs). Various types of immunochemically distinct AGEs, which were prepared in vitro by incubating bovine serum albumin with glucose, glyceraldehyde or glycolaldehyde, significantly decreased endothelial mRNA levels of PEDF Furthermore, H2O2 dose-dependently suppressed PEDF gene expression in ECs. Our present results suggest that AGEs could down-regulate mRNA levels of PEDF in ECs, probably via oxidative stress generation. The deleterious effects of AGEs on diabetic retinopathy could be due, at least in part, to their PEDF-inhibitory properties.     

Inhibitory effects of Terminalia chebula extract on glycation and endothelial cell adhesion

Terminalia chebula Retz. has been used in India for a long time to treat many diseases, and its extract was reported to have antidiabetic activity in vivo. In this study, T. chebula methanolic extract (TCE) containing 2.7 % chebulic acid was evaluated for its preventive effects against the formation of advanced glycation end products (AGEs) and endothelial cell dysfunction. When the effects of TCE on AGE formation and on protein crossing-linking by glycation with D-threose and lens crystallines were examined, TCE showed inhibitory activity in a dose-dependent manner, and the concentration of 1000 μg/mL presented an activity similar to that of 5 mM aminoguanidine as a positive control. Upon investigating the protective activity of TCE against AGE-induced vascular endothelium dysfunction, human umbilical vein endothelial cells (HUVEC) incubated with 100 μg/mL of AGEs had significantly enhanced reactive oxygen species (ROS) formation, whereas the treatment of T. chebula reduced AGE-induced ROS generation. The incubation of HUVEC with 100 μg/mL of AGEs caused a considerable increase in THP-1 monocytic cell adhesion, but this adhesion was reduced by the treatment of TCE. These results suggest that TCE is a potential agent for alleviating diabetic complications.     

Azelnidipine, a dihydropyridine-based calcium antagonist, inhibits angiotensin II-induced oxidative stress generation and downregulation of pigment epithelium-derived factor mRNA levels in microvascular endothelial cells

We have previously shown that azelnidipine, a long-acting dihydropyridine-based calcium antagonist (DHP), inhibited tumor necrosis factor-alpha-induced endothelial cell (EC) activation through its antioxidative properties. However whether azelnidipine could also block the angiotensin II (Ang II)-signaling in ECs remains to be elucidated. Since Ang II-type 1 receptor interaction could contribute to exacerbation of diabetic retinopathy by downregulating pigment epithelium-derived factor (PEDF) gene expression in ECs, we examined here whether azelnidipine inhibited the Ang II-induced reactive oxygen species (ROS) generation and subsequent PEDF gene suppression in microvascular ECs. Azelnidipine, but not nitrendipine, the other popular DHFP completely inhibited the Ang II-induced ROS generation in ECs. Furthermore, azelnidipine, but not nitrendipine, was found to partially restore decreased PEDF mRNA levels in Ang II-exposed ECs. The present study suggests that azelnidipine could inhibit the Ang II-induced decrease in PEDF mRNA levels in ECs through its antioxidative properties. Upregulation of PEDF by azelnidipine may become a therapeutic target for the treatment of diabetic retinopathy associated with hypertension.     

西红花酸对晚期糖化终产物诱导内皮细胞晚期糖基化终产物受体表达的抑制作用

目的：研究西红花酸对晚期糖基化终产物（AGE）诱导牛内皮细胞（BEC）中晚期糖基化终产物受体（RAGE）mRNA表达的抑制作用,并探讨其可能机制。方法：不同浓度的西红花酸（1、0.1、0.01μmol/L）预孵BEC细胞12h后,用AGE（100mg/L）刺激细胞12h,RT-PCR法测定RAGEmRNA的表达水平;ELISA法测定细胞间黏附分子-1（ICAM-1）的表达;试剂盒分别检测胞外超氧阴离子和硫代巴比妥酸反应产物（TBARS）浓度;同时,还用2,7-二氯荧光素（DCFH）测定了胞内H2O2的浓度,并用罗丹明123（Rh123）荧光法及MTT法分别检测细胞线粒体膜电位（MMP）水平和其琥珀酸脱氢酶（MSDH）的活性。结果：与AGE模型组相比,西红花酸能显著抑制RAGE mRNA的表达（P〈0.05）,降低胞外超氧阴离子和TBARS（P〈0.01或P〈0.05）及胞内H2O2水平;结果还显示,西红花酸能提高细胞MMP水平和MSDH活性。对ICAM-1蛋白表达也有抑制作用,且呈时间和剂量依赖性。结论：西红花酸可能通过清除AGE与RAGE结合产生的活性氧（ROS）来抑制RAGE mRNA的高表达。提示西红花酸对糖尿病血管病变有潜在的治疗价值。     

Crocetin prevents AGEs-induced vascular endothelial cell apoptosis.

Advanced glycation end products (AGEs) are causally correlated with diabetic vascular complications. AGEs triggered oxidative reaction then accelerated endothelial cell apoptosis is a critical event in the process of vascular complications. Crocetin, a carotenoid has been previously shown to have strong antioxidant activates. Therefore, this study was designed to investigate the role of crocetin on the prevention of AGEs-mediated cell apoptosis in bovine aortic endothelial cells (BEC) and the mechanisms involved. Exposure of BEC to 200 microg/ml AGEs for 48 h results in a significant increase in apoptotic rate, compared with control. AGEs-induced DNA fragmentation preferentially occurred in the S phase cells. Crocetin prevented AGEs-induced BEC apoptosis, which correlates with crocetin attenuation of AGEs mediated increase of intracellular reactive oxygen species (ROS) formation and elevation of intracellular Ca2+ concentration ([Ca2+]i) level (P<0.01 versus AGEs group). These results demonstrate that crocetin prevents AGEs-induced BEC apoptosis through ROS inhibition and [Ca2+]i stabilization and suggest that crocetin may exert a beneficial effect in preventing diabetes-associated vascular complications.     

Beneficial effects of metformin and irbesartan on advanced glycation end products (AGEs)-RAGE-induced proximal tubular cell injury

Advanced glycation end products (AGEs) and their receptor (RAGE) axis contributes to diabetic nephropathy. An oral hypoglycemic agent, metformin may have a potential effect on the inhibition of glycation reactions. Further, since a pathophysiological crosstalk between renin-angiotensin system (RAS) and AGEs-RAGE axis is involved in diabetic nephropathy, it is conceivable that metformin and irbesartan additively could protect against the AGEs-RAGE-induced tubular cell injury. In this study, we addressed the issues. Metformin dose-dependently inhibited the formation of AGEs modification of bovine serum albumin (BSA). Compared with AGEs-modified BSA prepared without metformin (AGEs-MF0), those prepared in the presence of 30 mM or 100 mM metformin (AGEs-MF30 or AGEs-MF100) significantly reduced RAGE mRNA level, reactive oxygen species (ROS) generation, apoptosis, monocyte chemoattractant protein-1 and transforming growth factor-β mRNA level in tubular cells. Irbesartan further inhibited the harmful effects of AGEs-MF0 or AGEs-MF30 on tubular cells. Our present study suggests that combination therapy with metformin and irbesartan may have therapeutic potential in diabetic nephropathy; it could play a protective role against tubular injury in diabetes not only by inhibiting AGEs formation, but also by attenuating the deleterious effects of AGEs via down-regulating RAGE expression and subsequently suppressing ROS generation.     

Possible involvement of advanced glycation end-products (AGEs) in the pathogenesis of Alzheimer's disease

Alzheimer's disease (AD) is the most common cause of dementia in developed countries. AD is characterized pathologically by the presence of senile plaques (SPs) and neurofibrillary tangles (NFTs), the major constituents of which are amyloid betaprotein and tau protein, respectively. Advanced glycation end-products (AGEs), senescent macroprotein derivatives formed at an accelerated rate under normal aging, can be identified immunohistochemically in both SPs and NFTs in AD patients. Further, recent clinical evidence has suggested diabetes mellitus as one of the risk factors for the development and progression of AD. Continuous hyperglycemia is a causative factor for diabetic vascular complications, and it enhances the generation of AGEs through the non-enzymatic glycation, thereby being involved in the pathogenesis of AD as well. Moreover, there is a growing body of evidence to show that the interaction of AGEs with a receptor for AGEs (RAGE) elicits reactive oxygen species generation and vascular inflammation, and subsequently alters various gene expressions in numerous types of cells, all of which could contribute to the pathological changes of diabetic vascular complications and AD. Indeed, we have recently found that glyceraldehyde-derived AGEs (Glycer-AGE) induce apoptotic cell death in cultured cortical neuronal cells. In addition, we also found that neurotoxic effect of diabetic serum on neuronal cells was blocked by neutralizing antibody raised against Glycer-AGE. In human AD brains, Glycer-AGE are actually detected in the cytosol of neurons in the hippocampus and para-hippocampal gyrus. These observations suggest that Glycer-AGE play a role in the pathogenesis of AD. In this review, we discuss the pathophysiological role for AGEs in the development and progression of AD, especially focusing on Glycer-AGE.     

Regulation of advanced glycation end product (AGE)-receptor (RAGE) system by PPAR-gamma agonists and its implication in cardiovascular disease

Non-enzymatic modification of proteins by reducing sugars leads to the formation of advanced glycation end products (AGEs), whose process has been reported to progress under physiological aging, oxidative stress or diabetic conditions. There is a growing body of evidence that AGEs and their receptor (RAGE) axis is involved in the pathogenesis of cardiovascular disease (CVD). Indeed, engagement of RAGE with AGEs is shown to elicit oxidative stress generation and subsequently evoke inflammatory and thrombogenic responses in various types of cells, including endothelial cells, smooth muscle cells, macrophages and renal cells, thus playing an important role in the development and progression of vascular injury in both diabetes and non-diabetes. These observations suggest that the inhibition of AGE formation, down-regulation of RAGE expression or blockade of the RAGE downstream signaling may be a promising therapeutic target for preventing CVD. Recently, peroxisome proliferator-activated receptor-γ (PPARγ) is involved in not only adipocyte differentiation, but also vascular homeostasis. Therefore, in this study, we review effects of PPARγ agonists on the AGE–RAGE system and their implication in CVD.     

Kinetics, role and therapeutic implications of endogenous soluble form of receptor for advanced glycation end products (sRAGE) in diabetes

Reducing sugars can react non-enzymatically with amino groups of protein to form Amadori products. These early glycation products undergo further complex reaction such as rearrangement, dehydration, and condensation to become irreversibly cross-linked, heterogeneous fluorescent derivatives, termed advanced glycation end products (AGEs). The formation and accumulation of AGEs have been known to progress at an accelerated rate in diabetes. There is a growing body of evidence that AGEs and their receptor (RAGE) axis is implicated in the pathogenesis of diabetic vascular complications. Indeed, the engagement of RAGE with AGEs is shown to elicit oxidative stress generation and subsequently evoke inflammatory responses in various types of cells, thus playing an important role in the development and progression of diabetic micro- and macroangiopathy. Moreover, administration of a recombinant soluble form of RAGE (sRAGE), has been shown to suppress the development of accelerated atherosclerosis in diabetic apolipoprotein E-null mice. These observations suggest that exogenously administered sRAGE may capture and eliminate circulating AGEs, thus protecting against the AGEs-elicited tissue damage by acting as a decoy receptor. Recently, endogenous sRAGE has been identified in humans. However, there is few comprehensive review about the regulation and role of endogenous sRAGE in diabetes. In the former part of this paper, we review the role of the AGE-RAGE system in the pathogenesis of diabetic vascular complications. Then we summarize in the latter part of this review the kinetics and pathophysiological role of endogenous sRAGE in diabetes. We also discuss the possibility that endogenous sRAGE may be a therapeutic target for the prevention of diabetic vascular complications.     

Nifedipine inhibits tumor necrosis factor-alpha-induced upregulation of monocyte chemoattractant protein-1 mRNA levels by suppressing CD40 expression in endothelial cells

There is a growing body of evidence that dihydropyridine-based calcium antagonists (DHPs) improve endothelial function, thus slowing the development and progression of atherosclerosis. We have previously shown that nifedipine, one of the most popular DHPs, inhibits tumor necrosis factor-alpha (TNF-alpha)-induced reactive oxygen species generation and subsequent monocyte chemoattractant protein-1 (MCP-1) expression in human umbilical vein endothelial cells (HUVEC). However, the molecular mechanism underlying this phenomenon remains to be elucidated. CD40, a cell surface receptor that belongs to TNF-alpha receptor, has been associated with the pathogenesis of chronic inflammatory diseases such as atherosclerosis. In this study, we investigated the involvement of CD40 in MCP-1 suppression by nifedipine in TNF-alpha-exposed HUVEC. Nifedipine completely inhibited TNF-alpha-induced upregulation of CD40 mRNA levels in HUVEC. Furthermore, antibody against human CD40 was found to significantly inhibit upregulation of MCP-1 mRNA levels in TNF-alpha-exposed HUVEC. These results demonstrate that nifedipine could inhibit the TNF-alpha-induced upregulation of MCP-1 mRNA levels via suppression of CD40 expression in HUVEC. Our present study suggests that blockade of CD40 signaling in endothelial cells may be a molecular target for the vasculoprotective property of nifedipine.