Background-Monocyte infiltration into the arterial wall and its activation is the central event in atherogenesis. Thus, monocyte chemoattractant protein-1 (MCP-1) might be a novel therapeutic target against atherogenesis. We and others recently reported that blockade or abrogation of the MCP-1 pathway attenuates the initiation of atheroma formation in hypercholesterolemic mice. It remains unclear, however, whether blockade of MCP-1 can limit progression or destabilization of established lesions. Methods and Results-We report here that blockade of MCP-1 by transfecting an N-terminal deletion mutant of the MCP-1 gene limited progression of preexisting atherosclerotic lesions in the aortic root in hypercholesterolemic mice.In addition, blockade of MCP-1 changed the lesion composition into a more stable phenotype, ie, containing fewer macrophages and lymphocytes, less lipid, and more smooth muscle cells and collagen. This strategy decreased expression of CD40 and the CD40 ligand in the atherosclerotic plaque and normalized the increased chemokine (RANTES and MCP-1) and cytokine (tumor necrosis factor ␣, interleukin-6, interleukin-1␤, and transforming growth factor ␤ 1 ) gene expression. These data suggest that MCP-1 is a central mediator in the progression and destabilization of established atheroma. Key Words: gene therapy Ⅲ atherosclerosis Ⅲ leukocytes Ⅲ inflammation Ⅲ lymphocytes A therosclerosis and its complications are the major cause of death in Western countries. Atherosclerosis is now recognized to involve chronic inflammatory and immune responses. 1,2 A considerable body of evidence supports the notion that various mediators such as adhesion molecules, cytokines, and chemokines are involved in the early initiation of atherosclerotic lesions. 1,2 The precise molecular mechanism underlying later complications of atherosclerosis, however, remains unclear. Investigation of this mechanism is clinically very important, because atherosclerotic complications such as acute myocardial infarctions and stroke develop during the later stages of atherosclerosis. Recently, several groups established that the immune mediator CD40 ligand (CD40L) and its receptor CD40 are crucial not only in the initiation of atheroma formation but also in the progression and destabilization of established atheroma. 3,4 CD40 receptor binding induces production of inflammatory cytokines, chemokines, matrix metalloproteinases (MMPs), and tissue factors in atheroma, which weakens the collagen frame of the plaque and renders it prone to rupture and thrombosis. 5,6 There are likely to be other potential mediators, however, that might contribute to the progression and destabilization of established atheroma. Conclusions-TheMonocyte chemoattractant protein-1 (MCP-1), a C-C chemokine, controls chemotaxis of mononuclear cells. 7,8 MCP-1 and its receptor (CCR2) pathway recently attracted much attention, because the MCP-1/CCR2 pathway seems to be involved in the inflammatory aspect of atherogenesis. Atheroma-forming cells (endothelial cells, smooth mu...

Abstract-Neointimal hyperplasia is a major cause of restenosis after coronary intervention. Because vascular injury is now recognized to involve an inflammatory response, monocyte chemoattractant protein-1 (MCP-1) might be involved in underlying mechanisms of restenosis. In the present study, we demonstrate the important role of MCP-1 in neointimal hyperplasia after cuff-induced arterial injury. In the first set of experiments, placement of a nonconstricting cuff around the femoral artery of intact mice and monkeys resulted in inflammation in the early stages and subsequent neointimal hyperplasia at the late stages. We transfected with an N-terminal deletion mutant of the human MCP-1 gene into skeletal muscles to block MCP-1 activity in vivo. This mutant MCP-1 works as a dominant-negative inhibitor of MCP-1. This strategy inhibited early vascular inflammation (monocyte infiltration, increased expression of MCP-1, and inflammatory cytokines) and late neointimal hyperplasia. In the second set of experiments, the cuff-induced neointimal hyperplasia was found to be less in CCR2-deficient mice than in control CCR2 ϩ/ϩ mice. The MCP-1/CCR2 pathway plays a central role in the pathogenesis of neointimal hyperplasia in cuffed femoral artery of mice and monkeys. Therefore, the MCP-1/CCR2 pathway can be a therapeutic target for human restenosis after coronary intervention. Key Words: remodeling Ⅲ growth substances Ⅲ inflammation Ⅲ monocytes Ⅲ gene transfer N eointimal hyperplasia is an essential stage in the development of restenosis after coronary intervention as well as atherosclerosis. 1 Therefore, studying the mechanism of neointimal hyperplasia in animals is indispensable to clarifying the underlying mechanisms and exploring the new treatment for vascular diseases. Recent evidence suggests that vascular injury may involve an inflammatory response that accelerates the recruitment and activation of monocytes through the activation of chemotactic factors including monocyte chemoattractant protein-1 (MCP-1). 2-4 MCP-1 is a potent chemotactic factor for monocytes. 5,6 Eliminating MCP-1 gene or blockade of MCP-1 signals has been shown to decrease atherogenesis in hypercholesterolemic mice. [7][8][9] However, no prior study addressed the definite role of monocytes or MCP-1-mediated signals in the development of neointimal hyperplasia after periarterial injury. Placement of nonconstricting cuff around the artery induces vascular inflammation at the early stages and subsequently causes intimal hyperplasia at the late stages. 10 -12 Wu et al 12 recently reported that angiotensin II type 1 receptor blockade attenuated vascular inflammation (monocyte infiltration and activation, upregulation of MCP-1 and inflammatory cytokines) induced by perivascular cuff placement. The latter study suggests the importance of MCP-1-mediated inflammation in mediating the formation of neointimal hyperplasia. However, no prior study has addressed the role of MCP-1 in the pathogenesis of neointimal hyperplasia after cuff placement.In the present st...

Monocyte chemoattractant protein-1 (MCP-1) may play an essential part in the formation of arteriosclerosis by recruiting monocytes into the arterial wall. Thus, we devised a new strategy for anti-MCP-1 gene therapy against arteriosclerosis by transfecting an amino-terminal deletion mutant (missing the amino-terminal amino acids 2 to 8) of the human MCP-1 gene into a remote organ (skeletal muscles). Intramuscular transduction with the mutant MCP-1 gene blocked monocyte recruitment induced by a subcutaneous injection of recombinant MCP-1. In a rat model in which the chronic inhibition of endothelial nitric oxide synthesis induces early vascular inflammation as well as subsequent coronary vascular remodeling, this strategy suppressed monocyte recruitment into the coronary vessels and the development of vascular medial thickening, but did not reduce perivascular fibrosis. Thus, MCP-1 is necessary for the development of medial thickening but not for fibrosis in this model. This new strategy may be a useful and feasible gene therapy against arteriosclerosis.

Monocyte/macrophage chemoattractant protein-1 (MCP-1), a potent chemoattractant chemokine and an activator for mononuclear cells, may play a role in the initiation and/or progression of pulmonary hypertension (PH). To determine whether blockade of a systemic MCP-1 signal pathway in vivo may prevent PH, we intramuscularly transduced a naked plasmid encoding a 7-NH(2) terminus-deleted dominant negative inhibitor of the MCP-1 (7ND MCP-1) gene in monocrotaline-induced PH. We also simultaneously gave a duplicate transfection at 2-wk intervals or skeletal muscle-directed in vivo electroporation (EP) to evaluate whether a longer or higher expression might be more effective. The intramuscular reporter gene expression was enhanced 10 times over that by EP than by simple injection, and a significant 7ND MCP-1 protein in plasma was detected only in the EP group. 7ND MCP-1 gene transfer significantly inhibited the progression of MCT-induced PH as evaluated by right ventricular systolic pressure, right ventricular hypertrophy, medial hypertrophy of pulmonary arterioles, and mononuclear cell infiltration into the lung. Differential effects of longer or higher transgene expression were not apparent. Although the in vivo kinetics of 7ND MCP-1 gene therapy should be studied further, these encouraging results suggest that an anti-inflammatory strategy via blockade of the MCP-1 signal pathway may be an alternative approach to treat subjects with PH.

Objective-Chronic inflammatory processes might be involved in the progression and destabilization of atherosclerotic plaques. Therefore, identification of the mechanism underlying arterial inflammatory function might lead to the development of novel therapeutic strategies. Angiotensin II (AngII) is implicated in atherogenesis by activating the vascular inflammation system, mainly through monocyte chemotaxis. Therefore, we hypothesized that AngII increases plaque size and promotes destabilization of established atheromas by activating the monocyte chemoattractant protein-1 (MCP-1) pathway. Methods and Results-We report here that 4-week infusion of AngII not only increased plaque size but also induced a destabilization phenotype (ie, increased macrophages and lipids and decreased collagen and smooth muscle cells) of pre-existing atherosclerotic lesions of hypercholesterolemic mice. AngII also enhanced the gene expression of inflammatory cytokines (TNF␣, etc.) and chemokines CCR2, etc Key Words: atherosclerosis Ⅲ hypercholesterolemia Ⅲ cell adhesion molecules Ⅲ inflammation Ⅲ gene therapy A therosclerosis and its complications are the major cause of death in Western countries. Recent evidence suggests that chronic inflammatory processes have an important role in atherosclerotic plaque progression, destabilization, and subsequent rupture/thrombosis, resulting in acute coronary syndrome and stroke. 1 Therefore, identification of the critical inflammatory pathway involved in plaque progression and destabilization of pre-existing established atheromas might aid in the development of novel therapeutic strategies to reduce atherothrombotic complications. Angiotensin II (AngII) is implicated in atherogenesis beyond its hemodynamic effects. 2 Infusion of AngII into hypercholesterolemic mice dramatically accelerates the development and/or progression of atherosclerotic lesions and the effects of AngII occurred independent of changes in arterial pressure or plasma lipid concentration. 3,4 The mechanism of AngII-induced enhancement of atherogenesis is probably multifactorial, and includes hemodynamic effects, endothelial dysfunction and activation, 5 oxidative stress, 6 and inflammation. 7,8 AngII increases monocyte chemotaxis, activates nuclear factor-B, and augments production of inflammatory cytokines and chemokines by arterial wall cells and monocytes. 9 -12 AngII is very important in the pathogenesis of atherothrombotic complications, as evidenced by clinical benefits of angiotensinconverting enzyme inhibition 13 and AngII receptor blockers. 14 There are no reports, however, that address the mechanism of AngII-induced enhancement of atherogenesis and plaque destabilization under in vivo conditions.Emerging evidence suggests that AngII activates cell inflammatory systems in arterial lesion. 1,2 Inflammatory changes in arterial lesions are characterized by the recruitment and activation of monocytes/macrophages, which are regulated by monocyte chemoattractant protein-1 (MCP-1). 15 Expression Vector7ND was constructed b...