RESUMEN
OBJECTIVE: LOX-1 is a multi-ligand receptor originally identified as the endothelial oxidized LDL receptor. LOX-1 expression is also induced in smooth muscle cells in response to proinflammatory and oxidative stimuli. Here, we report on the role of LOX-1 in intimal hyperplasia, in which proinflammatory and oxidative stimuli are increased. METHODS AND RESULTS: Left common carotid artery of rat was injured by a balloon catheter. The expression of LOX-1 was significantly increased within 24 h after the balloon injury and peaked at day 7. LOX-1 expression was observed predominantly in medial smooth muscle cells until day 3, and then shifted to predominantly intimal smooth muscle cells. At day 14, the expression was concentrated in the regenerated endothelial cells. To examine the contributory role of LOX-1 in the growth of intimal smooth muscle cells, rats were administered anti-LOX1 antibody intravenously every 3 days after balloon injury. Anti-LOX-1 antibody administration effectively suppressed intimal hyperplasia, oxidative stress, and leukocyte infiltration compared with control IgG. These findings suggest the importance of LOX-1 expression in the pathogenesis of neointimal formation in conjunction with oxidative stress and leukocyte infiltration. CONCLUSION: The LOX-1 expressed in smooth muscle cells is involved in intimal hyperplasia in a rat model of balloon injury. Manipulation of LOX-1 activity is a novel potential therapeutic target to prevent restenosis after angioplasty.
Asunto(s)
Traumatismos de las Arterias Carótidas/patología , Arteria Carótida Común/patología , Receptores Depuradores de Clase E/metabolismo , Túnica Íntima/patología , Animales , Anticuerpos Monoclonales/farmacología , Células CHO , Traumatismos de las Arterias Carótidas/metabolismo , Arteria Carótida Común/metabolismo , Cateterismo/efectos adversos , Cricetinae , Expresión Génica , Humanos , Hiperplasia , Inmunohistoquímica/métodos , Masculino , Microscopía Fluorescente , Ratas , Ratas Sprague-Dawley , Especies Reactivas de Oxígeno/análisis , Especies Reactivas de Oxígeno/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Receptores Depuradores de Clase E/genética , Receptores Depuradores de Clase E/inmunología , Túnica Íntima/metabolismoRESUMEN
The macrophage scavenger receptor (MSR) is a trimeric membrane protein which binds to modified low-density lipoprotein (LDL) and has been indicated in the development of atherosclerosis. It has recently been demonstrated that the N-terminal cytoplasmic domain of MSR has an important role in the efficient internalization and cell-surface expression of the receptor. This study shows that the N-terminal cytoplasmic domain in bovine was constructed using a peptide architecture technique in which the peptide chain was bundled at their C-terminus to yield a trimeric form and that this did not form an ordered structure. Furthermore, the binding proteins to the cytoplasmic domain of MSR were determined for the first time using a peptide affinity column. Sequence analyses of the specific binding proteins in bovine revealed that heat shock protein 90 (HSP90), heat shock protein 70 (HSP70), leucine aminopeptidase (LAP), adenocylhomocysteinase, and glyceraldehyde 3-phosphate dehydrogenase (GAPDH) were included. GST-pull-down assay and immunoprecipitation analyses on HSP90, HSP70, and GAPDH showed that all these proteins could bind to the cytoplasmic domain of MSR in vitro and in vivo. These proteins interact with the cytoplasmic domain directly and may have an effect on the functions of MSR such as internalization, cell-surface expression, and signal transduction.
Asunto(s)
Gliceraldehído-3-Fosfato Deshidrogenasas/metabolismo , Proteínas HSP70 de Choque Térmico/metabolismo , Proteínas HSP90 de Choque Térmico/metabolismo , Receptores Inmunológicos/química , Receptores Inmunológicos/metabolismo , Animales , Western Blotting , Células COS , Bovinos , Cromatografía de Afinidad , Dicroismo Circular , Electroforesis en Gel de Poliacrilamida , Gliceraldehído-3-Fosfato Deshidrogenasas/genética , Proteínas HSP70 de Choque Térmico/genética , Proteínas HSP90 de Choque Térmico/genética , Humanos , Pulmón/química , Pulmón/metabolismo , Fragmentos de Péptidos/síntesis química , Fragmentos de Péptidos/química , Fragmentos de Péptidos/metabolismo , Pruebas de Precipitina , Unión Proteica/fisiología , Estructura Terciaria de Proteína/fisiología , Receptores Inmunológicos/genética , Receptores Depuradores , Receptores Depuradores de Clase A , Relación Estructura-ActividadRESUMEN
Lectin-like oxidized low-density lipoprotein receptor (LOX-1/OLR1) has been suggested to play a role in the progression of atherogenesis. We analyzed the OLR1 gene and found a single nucleotide polymorphism (SNP), G501C, in patients with ischemic heart disease from a single family, which resulted in the missense mutation of K167N in LOX-1 protein. We compared the group of patients with myocardial infarction (MI) (n=102) with a group of clinically healthy subjects (n=102), and found that the MI group had a significantly high frequency of 501G/C+501C/C (38.2%) compared with the healthy group (17.6%; p<0.002). The odds ratio for the risk of MI associated with the 501G/C+501C/C genotype was 2.89 (95% CI, 1.51-5.53). These findings suggest that OLR1 or a neighboring gene linked with G501C SNP is important for the incidence of MI. Manipulating LOX-1 activity might be a useful therapeutic and preventative approach for coronary artery disease, especially for individuals with the G501C genotype of OLR1.