A product of growth arrest-specific gene 6 modulates scavenger receptor expression in human vascular smooth muscle cells

Introduction: Atherosclerosis is a leading cause of death in Western societies. Vasoactive peptide urotensin II (UII) is upregulated in atherosclerosis and several other cardiovascular diseases however further research is required to develop a complete understanding of UII’s role in the pathogenesis of atherosclerosis. Hypothesis: We hypothesized that UII stimulates calcification in vascular smooth muscle cells and that UII, urotensin II related peptide (URP) and UT receptor expression are upregulated in calcified aortic valves. Methods and Results: Human aortic smooth muscle cells (HASMC) were cultured in phosphate media (2.6mmol/L) for 13 days in the presence of varying concentrations of UII (0, 10, 50, 100nm) and the amount of calcium was measured with a calcium assay kit. Protein was extracted and measured with a protein assay kit. HASMC calcification was assessed as the ratio of calcium (μg)/protein (mg). HASMC calcification increased with increasing UII concentration and was significantly elevated in 100nm of UII (N=6, P<0.05) 13 days after incubation. We also examined UII, URP and UT protein expression in 90 carotid endarterectomies and 87 mitral, non-calcified and calcified aortic valves by immunohistochemistry. Multivariant Spearman correlation analyses in carotids revealed significant positive correlations between UII, URP and UT overall staining with calcification, remodeling and inflammation (P<0.05). In valves there was significant positive correlations between UII, URP and UT overall staining with calcification, fibrosis, remodeling, inflammation, lipid score and microvessels (P<0.05). Conclusion: The stimulatory effect of UII on vascular smooth muscle cell calcification as well as the upregulated expression of UII, URP and UT in calcified aortic valves suggests that the UT receptor system plays a key role in the pathogenesis of atherosclerosis and valve calcification.

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Abstract 381: IL-19 Inhibits Atherosclerosis in LDLR-/- Mice by Modulating Cholesterol Uptake in Macrophages and Vascular Smooth Muscle Cells

Arteriosclerosis Thrombosis and Vascular Biology ◽

10.1161/atvb.33.suppl_1.a381 ◽

2013 ◽

Vol 33 (suppl_1) ◽

Author(s):

Khatuna Gabunia ◽

Stephen P Ellison ◽

James M Richards ◽

Sheri E Kelemen ◽

Michael V Autieri

Keyword(s):

Smooth Muscle ◽

Vascular Smooth Muscle ◽

Smooth Muscle Cells ◽

Vascular Smooth Muscle Cells ◽

Atherosclerotic Plaque ◽

Scavenger Receptor ◽

Muscle Cells ◽

Wild Type ◽

Anti Inflammatory ◽

M2 Phenotype

IL-19 is a recently described, putative anti-inflammatory cytokine which had previously been ascribed to be leukocyte specific. IL-19 is not detected in normal artery, but we detected IL-19 in multiple cell types in human atherosclerotic plaque suggesting a role for this interleukin in atherosclerosis. The purpose of this study was to determine whether administration of exogenous IL-19 could attenuate development of pre-formed atherosclerotic plaque, and to identify potential molecular mechanisms. LDLR-/- mice were fed high-fat diet for 12 weeks and then administered with 10ng/g/day IL-19 or PBS for an additional 8 weeks. En face analysis demonstrated that IL-19 could halt, but not reverse existing plaque (26.7+/-1.7%, 41.03+/-3.1%, 23.70+/-2.6% for baseline, PBS control, and IL-19-treated mice). Foam cell formation by macrophages and vascular smooth muscle cells (VSMC) is a hallmark event during atherosclerosis. Nothing has been reported regarding IL-19 effects on macrophage or VSMC lipid uptake; we therefore investigated whether IL-19 affects macrophage and VSMC cholesterol handling. Addition of IL-19 to wild-type bone marrow derived macrophages (BMDM) significantly promoted oxLDL uptake, conversely, BMDM from IL-19-/- mice had significantly less oxLDL uptake compared to wild-type BMDM. Addition of IL-19 to wild type BMDM significantly increased expression of scavenger receptor B1 (SR-B1), and decreased expression of inflammatory cytokines TNFα, IL-12b, MCP1. Interestingly, converse results were obtained with VSMC, as addition of IL-19 to wild-type VSMC decreased uptake of oxLDL ( p<0.05 ) and decreased expression of scavenger receptor CD36. VSMC isolated from IL-19-/- mice had increased uptake of oxLDL (p<0.0001). It is reported that M2 macrophages participate in plaque regression. IL-19 decreased IL-12b and significantly promoted the polarization of anti-inflammatory M2 phenotype in BMDM as evidenced by the increased expression of YM1 and IL-10 mRNA. These data demonstrate that IL-19 can inhibit progression of existing atherosclerotic plaque by modulating lipid metabolism in VSMC and macrophages and by promoting macrophage differentiation into an alternative, anti-inflammatory M2 phenotype.

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K depletion alters angiotensin II receptor expression in vascular smooth muscle cells

AJP Cell Physiology ◽

10.1152/ajpcell.1990.258.5.c849 ◽

1990 ◽

Vol 258 (5) ◽

pp. C849-C854 ◽

Cited By ~ 53

Author(s):

S. L. Linas ◽

R. Marzec-Calvert ◽

M. E. Ullian

Keyword(s):

Smooth Muscle ◽

Angiotensin Ii ◽

Vascular Smooth Muscle ◽

Smooth Muscle Cells ◽

Vascular Smooth Muscle Cells ◽

Muscle Cells ◽

Receptor Expression ◽

Ang Ii ◽

Surface Receptors ◽

K Depletion

Dietary K depletion (KD) results in increases in the number of angiotensin II (ANG II) receptors and prevents ANG II-induced downregulation of ANG II receptors in membrane preparations of vessels from KD animals. Because dietary KD results in changes in factors other than K, we K depleted vascular smooth muscle cells (VSMC) in culture to determine the specific effects of KD on ANG II receptor expression and processing. Scatchard analysis of ANG II uptake at 4 degrees C revealed that the number of surface receptors was increased by 37% in cells in which K had been reduced by 45%. This increase also occurred in the presence of cycloheximide. To determine the effect of KD on receptor processing, we measured the number of surface receptors after exposure to ANG II in concentrations sufficient to cause down-regulation. After 30-min exposure to ANG II, the number of surface receptors was reduced by 63% in control cells but only 33% in KD cells. Thirty minutes after withdrawing ANG II, surface binding returned to basal levels in control cells but was still reduced by 20% in KD cells. To determine the functional significance of impaired receptor processing, we measured ANG II uptake at 21 degrees C. Uptake at 21 degrees C depends on the functional number of receptors, i.e., the absolute number of surface receptors and the rate at which receptors are recycled to the surface after ANG II binding. ANG II uptake at 21 degrees C was reduced by 50% in KD cells.(ABSTRACT TRUNCATED AT 250 WORDS)

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Regulation of Endothelin Receptor Expression in Vascular Smooth-Muscle Cells

Journal of Cardiovascular Pharmacology ◽

10.1097/00005344-199506263-00104 ◽

1995 ◽

Vol 26 ◽

pp. S348-350 ◽

Cited By ~ 8

Author(s):

Julie CM. Yu ◽

Anthony P. Davenport

Keyword(s):

Smooth Muscle ◽

Vascular Smooth Muscle ◽

Smooth Muscle Cells ◽

Vascular Smooth Muscle Cells ◽

Muscle Cells ◽

Receptor Expression ◽

Endothelin Receptor

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Agents which increase cyclic AMP have diverse effects on low-density-lipoprotein-receptor function in human vascular smooth-muscle cells and skin fibroblasts

Biochemical Journal ◽

10.1042/bj2670607 ◽

1990 ◽

Vol 267 (3) ◽

pp. 607-614 ◽

Cited By ~ 9

Author(s):

A Middleton ◽

B Middleton

Keyword(s):

Smooth Muscle ◽

Cyclic Amp ◽

Vascular Smooth Muscle ◽

Smooth Muscle Cells ◽

Vascular Smooth Muscle Cells ◽

Ldl Receptor ◽

Muscle Cells ◽

Skin Fibroblasts ◽

Receptor Expression ◽

Low Density

Receptor-mediated binding and metabolism of low-density lipoproteins (LDL) in cultured human vascular smooth-muscle cells and skin fibroblasts are altered by increased cellular cyclic AMP concentrations. However, the LDL receptor does not respond to changes in cyclic AMP concentration in a simple manner. The activation of adenylate cyclase with forskolin, or the addition of membrane-permeant cyclic AMP analogues, initially decreases the expression of the LDL receptor, but is followed by a substantial increase in receptor expression after 24 h. This increase does not occur in the presence of inhibitors of RNA or protein synthesis, and is due to doubling of the Bmax. of the LDL receptor, without alteration of its affinity for LDL. By contrast, elevation of cyclic AMP concentration by inhibition of phosphodiesterases results in decreased receptor expression throughout the 24 h period. These two response patterns are reproducible phenomena, consistently observed in low-passaged cells derived from seven unrelated individuals.

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