Genetics of Atherosclerosis in a Murine Model

动脉粥样硬化性冠状动脉疾病是美国最常见的死亡原因。小鼠动脉粥样硬化模型在阐明动脉粥样硬化的发病机制和通过检测候选基因的过表达或低表达来鉴定动脉粥样硬化修饰基因方面提供了非常丰富的信息。此外，公正但费力的遗传学方法已被用于绘制改变动脉粥样硬化易感性的小鼠基因的位点;并且，现在正在辨别这些基因的身份。通过无偏遗传学方法发现的动脉粥样硬化修饰基因可能阐明以前不知道的参与动脉粥样硬化形成的途径。我们使用了一组apoE缺陷小鼠， 沿着的近交系背景菌株与一种称为“计算机定量性状基因座（QTL）定位”的计算方法，以预测小鼠动脉粥样硬化易感基因的基因组位置。我们检测到5个基因座，作为进一步研究的候选者，其中两个先前被确定为显着的动脉粥样硬化修饰基因座使用更传统的QTL方法，涉及育种的F2小鼠的大队列。这项工作的总体目标是确定这些和新发现的QTL的动脉粥样硬化易感基因，并评估这些基因的人类直系同源物中的常见多态性是否与心血管疾病相关。我们建议通过在动脉粥样硬化易感的DBA/2品系上繁殖apoE缺陷小鼠的F2队列来证实这些计算机QTL 和抗动脉粥样硬化AKR菌株。对于每只小鼠，将定量评估动脉粥样硬化病变面积，并进行基因组扫描，以进行传统的QTL分析，以确认计算机QTL并鉴定其他QTL。为了验证每个QTL，将在次级同类系中评估病变，其中来自一个品系的QTL区间与另一个品系交配。这些次级同类系将进一步育种以产生重组体，以便将QTL区间精细定位到约1 Mb。该间隔中的所有基因将通过小鼠基因组草图序列鉴定。将使用多种平行方法来鉴定责任基因，包括表达微阵列， 每个区间基因中的菌株特异性多态性，并通过在转基因小鼠中过表达来测试候选基因。一旦确定，这些基因将成为人类遗传关联研究的候选基因，以确定与心血管疾病相关的常见变异。

Atherosclerotic coronary disease is the most common cause of mortality in the United States. Mouse models of atherosclerosis have been very informative in elucidating the pathogenesis of atherosclerosis and in the identification of atherosclerosis modifying genes by testing candidate genes through their under or over expression. Additionally, unbiased but laborious genetic methods have been used to map the loci of mouse genes that alter atherosclerosis susceptibility; and, the identity of these genes are now being discerned. Atherosclerosis modifying genes discovered by the unbiased genetic method may illuminate pathways not previously known to be involved in atherogenesis. We have used a panel of apoE-deficient mice bred onto 6 inbred background strains along with a computational method called "in silico quantitative trait loci (QTL) mapping" to predict the genomic location of mouse atherosclerosis susceptibility genes. We detected 5 loci that stood out as candidates for further study, two of which were previously identified as significant atherosclerosis modifying loci using a more traditional QTL method that involves breeding a large cohort of F2 mice. The overall goal of the proposed work is identify the atherosclerosis susceptibility genes that underlie each of these and newly discovered QTLs, and assess whether common polymorphism in the human orthologs of these genes are associated with cardiovascular disease. We propose to confirm these in silico QTLs by breeding an F2 cohort between apoE-deficient mice on the atherosclerosis susceptible DBA/2 strain and the atherosclerosis resistant AKR strain. For each mouse, atherosclerosis lesion area will be quantitatively assessed and a genome scan will be preformed in order to perform a traditional QTL analysis to confirm the in silico QTLs and identify additional QTLs. To validate each QTL, lesions will be assessed in secondary congenic lines in which the QTL interval from one strain is bred onto the other strain. These secondary congenic lines will be bred further to generate recombinants in order to fine map the QTL interval to approximately 1 Mb. All of the genes in this interval will be identified via the mouse draft genome sequence. Multiple parallel approaches will be used to identify the responsible gene including expression micorarrays, identifying strain specific polymorphisms in the genes of each interval, and testing candidate genes by overexpression in transgenic mice. Once identified, these genes will be candidates for human genetic association studies to identify common variations associated with cardiovascular disease.