Biomedical subjects

Vicenta Llorente-Cortés

Publications and source records attributed to Vicenta Llorente-Cortés.

7 recordsLinked to original sources

PubMed2006

Aggregated low density lipoproteins decrease metalloproteinase-9 expression and activity in human coronary smooth muscle cells.

Plaque stability largely depends on vascular smooth muscle cell (VSMC) function. VSMC secrete metalloproteinases (MMPs), matrix degrading endopeptidases, that regulate VSMC migration and function. Among them, gelatinase B or MMP-9 seems to have a protective effect by promoting a stable plaque phenotype. In macrophage foam cells oxidized LDL (oxLDL) uptake regulates MMP-9 expression. However, it is unknown whether VSMC-lipid loading by aggregated LDL (agLDL) internalization produces any effect on MMP-9 production by human resident vascular cells. In the present study, we analyzed the effect of lipid-internalization in MMP-9 and MMP-2 expression and activity and its consequences in VSMC migration. Our results show that agLDL-internalization down-regulates MMP-9 activity in a time-dependent manner up to 42% at 48h and in a dose-dependent manner up to 87% at 300 microg/mL. nLDL induced similar but not sustained decrease on MMP-9 activity. However, neither agLDL nor nLDL exerted any significant effect on MMP-2 and TIMP-1. VSMC regrowth after a scratch injury was significantly reduced by exposure to agLDL. We conclude that agLDL-lipid loading reduces MMP-9 activity and this effect is associated to inhibition of VSMC migration. Thus, agLDL internalization may have consequences on vascular remodeling after injury, and the stability of lipid-rich atherosclerotic plaques.

Cell Movement↗

PubMed2005

Cholesteryl esters of aggregated LDL are internalized by selective uptake in human vascular smooth muscle cells.

OBJECTIVE: Low-density lipoprotein (LDL) receptor-related protein (LRP1) mediates the internalization of aggregated LDL (agLDL)-LDL trapped in the arterial intima bound to proteoglycans-into human vascular smooth muscle cells (VSMC). LRP1-mediated agLDL uptake induces high-intracellular cholesteryl ester (CE) accumulation. The aim of this study was to characterize the mechanism of agLDL internalization in human VSMC. METHODS AND RESULTS: The lipidic component of LDL was labeled with [3H] and the apolipoprotein component with [(125)I]. We found that >90% of intracellular CE derived from agLDL uptake was not associated with apoB100 degradation but was selectively taken up from agLDL. The inhibition of LRP1 expression by small interfering RNA treatment led to a decrease of 80+/-0.05% in agLDL-CE selective uptake. AgLDL induced intracellular CE accumulation without a concomitant CE synthesis. Cytosolic and cytoskeletal proteins were not required for CE transport. Electron and confocal microscopy experiments indicate that CE derived from agLDL accumulated in adipophilin-stained lipid droplets that were not removable by high-density lipoprotein. CONCLUSIONS: Taken together, these results demonstrate that LRP1 mediates the selective uptake of CE from agLDL and that CE derived from agLDL is not intracellularly processed but stored in lipid droplets in human VSMC.

Antimalarials↗

PubMed2005

LDL receptor-related protein and the vascular wall: implications for atherothrombosis.

LDL receptor-related protein 1 (LRP1) is highly expressed in the vascular wall and is mainly associated with macrophages and vascular smooth muscle cells (VSMCs). Overexpression of LRP1 in atherosclerotic lesions has been demonstrated in several animal models and human lesions. Clinical studies have suggested a relation between alterations in LRP1 expression and coronary heart disease. Indeed, it has been demonstrated that LRP1 gene expression is increased in blood mononuclear cells from patients with coronary obstruction and that the LRP1 mRNA-protein expression ratio is altered in coronary patients. Taken together, these results seem to suggest that LRP1 may be a pivotal receptor in the etiology of atherosclerosis. Our group has contributed to the elucidation of the physiopathologic role of LRP1 in the vascular wall by demonstrating that LRP1-mediated, matrix-retained LDL internalization could be crucial for VSMC-foam cell formation, that LRP1 is upregulated by lipid during human atherosclerotic lesion progression, and that LRP1-mediated aggregated LDL uptake causes the prothrombotic transformation of the vascular wall. Therefore, LRP1 seems to play a pathologic function during atherosclerotic lesion progression; however, LRP1 also seems to be essential for embryonic development and for the maintenance of vascular integrity. The protective effect of LRP1 in the vessel wall seems to be mainly due to its role in controlling certain signaling pathways. In this review, we will focus on the description of the main physiopathologic functions of LRP1 in the vascular wall.

Arteriosclerosis↗

PubMed2004

Aggregated low-density lipoprotein uptake induces membrane tissue factor procoagulant activity and microparticle release in human vascular smooth muscle cells.

BACKGROUND: Tissue factor (TF) is the main initiator of the arterial blood coagulation system, and aggregated LDL (agLDL) are found in the arterial intima. Our hypothesis is that agLDL internalization by vascular smooth muscle cells (VSMCs) may trigger TF-procoagulant activity. METHODS AND RESULTS: Cultured human VSMCs were obtained from human coronary arteries of explanted hearts during transplant operations. VSMCs were incubated with native LDL (nLDL) or agLDL. TF mRNA was analyzed by real-time polymerase chain reaction, and cellular and released TF protein antigen were analyzed by Western blot. TF microparticle (MP) content was analyzed by flow cytometry and TF activity by a factor Xa generation test. Both nLDL and agLDL strongly and equally increased TF mRNA and cell membrane protein expression, by approximately 5- and 9-fold, respectively. A sustained TF procoagulant activity was induced by agLDL but not by nLDL (agLDL 2.46+/-0.22 versus nLDL 0.72+/-0.12 mU/mg protein at 12 hours). AgLDL increased TF antigen release (agLDL 5.64+/-0.4 versus nLDL 3.28+/-0.22 AU) and TF MP release (agLDL 89.85+/-8.51 versus nLDL 19.69+/-4.59 TF MP/10(3) cells). TF activation and release induced by agLDL is not related to apoptosis. Blockade of LDL receptor-related protein, a receptor for agLDL, prevented the agLDL-induced release of TF protein and TF MP. CONCLUSIONS: VSMC-TF expression is upregulated by both nLDL and agLDL. However, only agLDL engagement to LDL receptor-related protein induced cellular TF procoagulant activity and TF release by human VSMCs.

Annexin A5↗

PubMed2002

Low-density lipoprotein upregulates low-density lipoprotein receptor-related protein expression in vascular smooth muscle cells: possible involvement of sterol regulatory element binding protein-2-dependent mechanism.

BACKGROUND: Low-density lipoprotein (LDL) receptor-related protein (LRP) is highly expressed in vascular smooth muscle cells (VSMCs) of both normal and atherosclerotic lesions. However, little is known about LRP regulation in the vascular wall. METHODS AND RESULTS: We analyzed the regulation of LRP expression in vitro in human VSMCs cultured with native LDL (nLDL) or aggregated LDL (agLDL) by semiquantitative reverse transcriptase-polymerase chain reaction, real-time polymerase chain reaction, and Western blot and in vivo during diet-induced hypercholesterolemia by in situ hybridization. LRP expression in human VSMCs is increased by nLDL and agLDL in a time- and dose-dependent manner. Maximal induction of LRP mRNA expression was observed after 24 hours of exposure to LDL. However, agLDL induced higher LRP mRNA expression (3.0-fold) than nLDL (1.76-fold). LRP mRNA upregulation was associated with an increase on LRP protein expression with the greatest induction by agLDL. VSMC-LRP upregulation induced by nLDL or agLDL was reduced by an inhibitor of sterol regulatory element binding protein (SREBP) catabolism (N-acetyl-leucyl-leucyl-norleucinal). In situ hybridization analysis indicates that there is a higher VSMC-LRP expression in hypercholesterolemic than in normocholesterolemic pig aortas. CONCLUSIONS: These results indicate that LRP expression in VSMCs is upregulated by intravascular and systemic LDL.

Animals↗

PubMed2002

Differential role of heparan sulfate proteoglycans on aggregated LDL uptake in human vascular smooth muscle cells and mouse embryonic fibroblasts.

OBJECTIVE: Low density lipoprotein (LDL) receptor-related protein (LRP) binds and internalizes aggregated LDL (agLDL) in human vascular smooth muscle cells (VSMCs). To analyze the contribution of proteoglycans (PGs) to agLDL uptake in human VSMCs, in wild-type mouse embryonic fibroblasts (MEF line), and in LRP-deficient mouse embryonic fibroblasts (PEA13 line). METHODS AND RESULTS: PGs in the medium and cellular and extracellular matrix have been isolated by metabolic radiolabeling with [35S]Na2SO4 and characterized by selective digestion with heparinase I and III (4 U/mL each) and chondroitinase ABC (2 U/mL). To examine the contribution of PGs and LRPs to agLDL internalization, nonexpressing and LRP-expressing cells, treated or not with polysaccharidase, were incubated with agLDL (25, 50, and 100 micro g/mL) for 18 hours. In human VSMCs, agLDL was unable to induce cholesteryl ester (CE) accumulation in antisense LRP-oligodeoxynucleotide-treated cells, and heparan sulfate (HS)-PG depletion leads to a reduction of the CE accumulation. In mouse fibroblasts, PEA13 compared with MEF showed lower, but still considerable, CE accumulation, and HS-PG depletion almost completely inhibited CE accumulation. CONCLUSIONS: In MEF, HS-PGs can function alone as receptors that bind and internalize agLDL in the absence of LRP, but in human VSMCs, although HS-PGs facilitate agLDL binding to the cells, LRP is essential for agLDL internalization.

Animals↗

PubMed2002

Human coronary smooth muscle cells internalize versican-modified LDL through LDL receptor-related protein and LDL receptors.

Versican-like proteoglycans are the main component of the intimal extracellular matrix interacting with low density lipoprotein (LDL). The aim of this study has been to investigate the receptors involved in versican-modified LDL uptake by human vascular smooth muscle cells (VSMCs). We have found that versican-LDL interaction leads to the following: (1) monomeric LDL particles that are similar in size and electrophoretic mobility to native LDL but that have a higher capacity to induce intracellular cholesteryl ester (CE) accumulation and (2) fused LDL particles similar in size to those obtained by vortexing. The precipitable fraction of versican-LDL, composed of 50% monomeric and 50% fused LDL particles, induced a dose-response increase in the CE content of VSMCs. Anti-LDL receptor antibody decreased the CE accumulation derived from monomeric LDL particles by 88 +/- 3% and that derived from the total precipitable fraction by 45 +/- 3%. Inhibition of LDL receptor-related protein expression by antisense oligodeoxynucleotides reduced the CE accumulation derived from the precipitable fraction by 65 +/- 2.8%, whereas it did not produce any effect on the CE accumulation derived from monomeric LDL. These results suggest that versican-LDL induces CE accumulation in human VSMCs by the LDL receptor (monomeric particles) and LDL receptor-related protein (fused LDL).

Cell Membrane↗