Rat Aortic MCP-1 and Its Receptor CCR2 Increase With Age and Alter Vascular Smooth Muscle Cell Function

Abstract

Objective-With age, rat arterial walls thicken and vascular smooth muscle cells (VSMCs) exhibit enhanced migration and proliferation. Monocyte chemotactic protein-1 (MCP-1) affects these VSMC properties in vitro. Because arterial angiotensin II, which induces MCP-1 expression, increases with age, we hypothesized that aortic MCP-1 and its receptor CCR2 are also upregulated and affect VSMC properties. Methods and Results-Both MCP-1 and CCR2 mRNAs and proteins increased in old (30-month) versus young (8-month) F344ϫBN rat aortas in vivo. Cellular MCP-1 and CCR2 staining colocalized with that of ␣-smooth muscle actin in the thickened aortas of old rats and were expressed by early-passage VSMCs isolated from old aortas, which, relative to young VSMCs, exhibited increased invasion, and the age difference was abolished by vCCI, an inhibitor of CCR2 signaling. MCP-1 treatment of young VSMCs induced migration and increased their ability to invade a synthetic basement membrane. The MCP-1-dependent VSMC invasiveness was blocked by vCCI. After MCP-1 treatment, migration and invasion capacities of VSMCs from young aortas no longer differed from those of VSMCs isolated from older rats. Key Words: chemokines Ⅲ aging Ⅲ aorta Ⅲ vascular smooth muscle cells Ⅲ invasion A ging is the major risk factor for the development of atherosclerosis and hypertension, which have an important impact on Western society because they lead to myocardial infarction, stroke, and heart failure. 1-3 Arterial remodeling accompanies advancing age in all species, from rodents to nonhuman primates to humans, and the mechanisms involved in this remodeling likely confer on aging the status of the major risk factor for vascular diseases. 1,2 Specific facets of age-associated remodeling include luminal dilation, thickening of the intimal and medial layers with cellular and extracellular matrix reorganization, increased stiffness, and endothelial dysfunction. 4 -6 Studies from our laboratory and others have shown that diffuse intimal thickening with aging is characterized by accumulation of fibronectin, collagen, and vascular smooth muscle cells (VSMCs), with an increase in matrix metalloproteinase (MMP)-2 and angiotensin II (Ang II) expression. [7][8][9][10][11] In addition, the expression of aortic intracellular adhesion molecule and transforming growth factor-␤1 markedly increases with age, and these molecules localize to MMP-2-staining positive areas. 12 Arterial aging is also characterized by an increase in NAD(P)H oxidase activity and reactive oxygen species production and a reduction in nitric oxide (NO) bioavailability. [13][14][15][16] In addition, increased arterial levels of proinflammatory cytokines, such as tumor necrosis factor-␣ and interleukin-6, among others, accompany aging. [17][18][19][20] Structural and biochemical changes that occur within large arteries with aging are accompanied by a shift of the VSMC phenotype from the "contractile" to the "synthetic" state, characterized by an increased proliferative and migratory responsiveness to...

Varicose Remodeling of Veins Is Suppressed by 3‐Hydroxy‐3‐Methylglutaryl Coenzyme A Reductase Inhibitors

“…In this context, we showed that these environmental conditions activate the transcription factor activator protein 1 (AP‐1), which controls expression of genes with products that promote cellular activity and proliferation in the venous wall. Among them, monocyte chemoattractant protein 1 (MCP1) contributes to the recruitment of circulating monocytes and proliferation of vascular smooth muscle cells (SMCs),5, 6 whereas matrix metalloproteinase (MMP) 2 promotes degradation and thus structural rearrangement of the extracellular matrix in the vessel wall 7, 8. Consequently, an increase in wall stress stimulates expression of MMP2 and elevates gelatinase activity in the media of affected veins and human venous SMCs (HUVSMCs) 9, 10.…”

Calorie Restriction Curbs Proinflammation That Accompanies Arterial Aging, Preserving a Youthful Phenotype

“…Immunoblotting of supernatant from thoracic aortae homogenates or VSMC lysates were performed as previously described 5, 6, 19, 20. Primary antibodies used for Western blotting are listed in Table.…”

“…VSMCs were enzymatically isolated as previously described 5, 6, 19, 20. Briefly, young and old AL and CR F344 rat thoracic aortae (n=3 animals/group) were rinsed in Hanks balanced salt solution containing 50 μg/mL penicillin, 50 μg/mL streptomycin, and 0.25 μg/mL amphotericin B (ThermoFisher).…”

Monocyte chemoattractant protein-1 has prosclerotic effects both in a mouse model of experimental diabetes and in vitro in human mesangial cells

“…SB202190 and the rabbit anti-fibronectin antibody were from Calbiochem (Nottingham, UK). The protein kinase C (PKC) peptide inhibitors PKC [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36] and SN50 were from Alexis (Nottingham, UK) and the TransAM nuclear factor kappa B (NF-κB) kit was from Active Motif (Rixensart, Belgium). The FITC-conjugated rabbit antimouse antibody, the rabbit anti-fibronectin antibody and the avidin/biotin blocking solution were from DAKOCytomation (Glostrup, Denmark).…”

“…Inhibition experiments on basal protein production were carried out simultaneously. RS102895 (6 μmol/l), anti-TGF-β1 neutralising antibody (2 μg/ml), SN50 (18 μmol/l), SB202190 (1 μmol/l) and PKC [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36] (4 μmol/l) were used to block CCR2, TGF-β1, NF-κB, p38 mitogen-activated protein (MAP) kinase and PKC, respectively. The specificity and selectivity of the inhibitors used has been previously demonstrated [22][23][24][25].…”