QTL analysis of carotid atherosclerosis

描述（由申请人提供）：卒中是美国第三大死亡原因和第一大残疾原因，很大一部分缺血性卒中是由颈动脉粥样硬化引起的，其导致血管狭窄并阻断流向大脑的血流。本研究的目的是利用新的载脂蛋白E缺陷（apoE-/-）小鼠模型来鉴定导致颈动脉粥样硬化发展的遗传因素。具有C57 BL/6（B6）遗传背景的ApoE-/-小鼠在颈动脉中出现了在人类中观察到的动脉粥样硬化病变的所有阶段。我们最近的研究表明，通过与C3 H/HeJ（C3 H）小鼠异交，病变可以显著减少，证明了小鼠疾病过程的遗传控制。在体外，C3 H小鼠的内皮细胞对氧化LDL的反应不如B6内皮细胞。我们推测，影响对氧化低密度脂蛋白的反应的遗传改变有助于C3 H小鼠对颈动脉粥样硬化的抵抗。为了检验这一假设，将B6.apoE-/-小鼠与C3H.apoE-/-小鼠杂交以产生F1小鼠，随后将其相互杂交以产生F2小鼠。从6周龄开始，F2小鼠与F1和两个亲本品系一起喂食西方饮食12周。将通过光学显微镜测量颈动脉中的动脉粥样硬化病变。将采集空腹血脂和炎症标志物的血液。将使用微卫星标记进行全基因组扫描，以确定与B6和C3 H菌株之间表型差异相关的遗传基因座。将进行标记和表型的统计关联，以识别特征背后的基因座。在基因组筛查检测到与动脉粥样硬化病变相关的染色体区域后，我们将对其他紧密间隔的多态性标记进行分型。将通过构建同源菌株来剖析动脉粥样硬化病变的一到两个主要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.