Low density lipoproteins, vascular smooth muscle cell function and vascular remodeling
High levels of circulating low-density lipoproteins (LDL) are one of the major cardiovascular risk factors. Hypercholesterolemia induces endothelial dysfunction and chronic intimal inflammatory cell accumulation, hallmarks of the initiation of atherosclerosis. Additionally, growing human atheroscler...
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| Tipo de recurso: | tesis doctoral |
| Estado: | Versión publicada |
| Fecha de publicación: | 2013 |
| País: | España |
| Institución: | CBUC, CESCA |
| Repositorio: | TDR. Tesis Doctorales en Red |
| OAI Identifier: | oai:www.tdx.cat:10803/283471 |
| Acceso en línea: | http://hdl.handle.net/10803/283471 |
| Access Level: | acceso abierto |
| Palabra clave: | Atherosclerosis Low density lipoproteins Vascular remodeling Vascular smooth muscle cells Cell migration Urokinase plasminogen activator HMG-CoA reductase inhibitors HSP27 Aterosclerosis Lipoproteínas de bajas densidad Remodelado vascular Células musculares lisas vasculares Migración celular Activador del plasminogeno tipo uroquinasa Inhibidores de la HMG-CoA reductasa 616.1 |
| Sumario: | High levels of circulating low-density lipoproteins (LDL) are one of the major cardiovascular risk factors. Hypercholesterolemia induces endothelial dysfunction and chronic intimal inflammatory cell accumulation, hallmarks of the initiation of atherosclerosis. Additionally, growing human atherosclerotic plaques show proliferation and migration of vascular smooth muscle cells (VSMC) towards the intima producing remodeling of the vascular wall. However, those plaques that are most prone to rupture show a progressive loss of VSMC becoming soft and vulnerable and these lipid-rich high risk plaques cause clinical episodes resulting in morbid or fatal ischemic events. The mechanisms involved in the transformation of a plaque into a vulnerable VSMC-depleted atheroma have not been completely elucidated. Lipid-rich-VSMC have an impaired vascular repair function due to changes in cytoskeleton proteins. However, the effects of LDL on VSMC function during plaque remodeling and vascular repair are not fully understood. Thus, the aim of this thesis was to investigate early changes directly induced by LDL on VSMC phenotype and function and to identify the molecular mechanisms involved. This thesis demonstrates that the cardiovascular risk of hypercholesterolemia involves the interaction of LDL with VSMC and the regulation at a molecular level of different pathways that converge in the cell’s migratory capacity. Migratory function of lipid-loaded VSMC can be restored by inhibition of 3-hydroxy-methylglutaryl coenzyme A (HMG-CoA) through a Rho kinase and myosin light chain phosphatase dependent mechanism. In addition, the studies performed in this thesis show that LDL affect VSMC adhesion, migration and cytoskeleton dynamics through the abrogation of the urokinase-plasminogen activator (uPA)/uPA receptor (uPAR) system function and by modulation of HSP27 phosphorylation and subcellular localization. |
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