QTL analysis of carotid atherosclerosis

描述(申请人提供)：中风是美国第三大致死原因和第一大致残原因，很大一部分缺血性中风是由颈动脉粥样硬化引起的，颈动脉粥样硬化导致血管狭窄并阻止流向大脑的血液。这项建议的目的是利用新的载脂蛋白E缺陷(apoE-/-)小鼠模型，识别导致颈动脉粥样硬化发展的遗传因素。在C57BL/6(B6)遗传背景上的APOE-/-小鼠在颈动脉中发展为人类所见的所有阶段的动脉粥样硬化病变。我们最近的研究表明，通过与C3H/HeJ(C3H)小鼠进行异种杂交，可以显著减少损伤，证明了小鼠疾病过程的基因控制。在体外，C3H型小鼠内皮细胞对氧化低密度脂蛋白的反应不如B6内皮细胞。我们假设，影响氧化低密度脂蛋白反应的基因改变有助于C3H小鼠对颈动脉粥样硬化的抵抗力。为了验证这一假设，B6.apoE-/-小鼠将与C3H.apoE-/-小鼠杂交产生F1小鼠，然后再杂交产生F2小鼠。从6周大的F2小鼠开始，连同F1和两个亲本品系，将以西方饮食喂养12周。颈动脉的动脉粥样硬化病变将通过光学显微镜进行测量。将采集血液以检测空腹血脂和炎症标志物。将使用微卫星标记进行全基因组扫描，以确定与B6和C3H菌株表型差异有关的遗传位点。将进行标记和表型的统计关联，以确定潜在性状的基因座。在基因组筛选检测到与动脉粥样硬化病变相关联的染色体区域后，我们将键入额外的紧密间隔的多态标记。通过构建同源品系，将分离到一个到两个与动脉粥样硬化病变相关的主效QTL。

DESCRIPTION (provided by applicant): Stroke is the third leading cause of mortality and the leading cause of disability in the United States, and a significant fraction of ischemic strokes are caused by carotid atherosclerosis, which results in stenosis of the vessels and blocks the blood flow to the brain. The goal of this proposal is to identify genetic factors that contribute to the development of carotid atherosclerosis, using the novel apolipoprotein E-deficient (apoE-/-) mouse model. ApoE-/- mice on the C57BL/6 (B6) genetic background develop all phases of atherosclerotic lesions seen in humans in carotid arteries. Our recent studies show that the lesions can be dramatically diminished by outcross with C3H/HeJ (C3H) mice, demonstrating the genetic control of the disease process in the mice. In vitro, endothelial cells of C3H mice are not as responsive to oxidized LDL as B6 endothelial cells. We hypothesize that a genetic alteration that influences the response to oxidized LDL contributes to the resistance of C3H mice to carotid atherosclerosis. To test this hypothesis, B6.apoE-/- mice will be crossed with C3H.apoE-/- mice to generate F1 mice, which will be subsequently intercrossed to generate F2 mice. Starting at 6 weeks of age, the F2 mice, together with the F1 and the two parental strains, will be fed a Western diet for 12 weeks. Atherosclerotic lesions in carotid arteries will be measured by light microscopy. Blood will be collected for fasting lipid profiles and inflammatory markers. Genome wide scan will be performed using microsatellite markers to define the genetic loci that are linked to differences in phenotypes between B6 and C3H strains. Statistical associations of the markers and the phenotypes will be performed to identify loci underlying the traits. After the genome screen has detected chromosomal regions that show linkage with atherosclerotic lesions, we will type additional closely spaced polymorphic markers. One to two major QTLs for atherosclerotic lesions will be dissected through construction of congenic strains.