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低表达或高表达来识别动脉粥样硬化修饰基因方面提供了非常丰富的信息。此外，无偏见但费力的遗传学方法已经被用来绘制改变动脉粥样硬化易感性的小鼠基因的位置；现在，这些基因的身份正在被识别。通过无偏向遗传方法发现的动脉粥样硬化修饰基因可能会阐明以前未知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，这些小鼠繁殖到6岁以上 利用近亲交配背景菌株和一种名为“电子数量性状基因座(QTL)定位”的计算方法来预测小鼠动脉粥样硬化易感基因的基因组位置。我们检测到了5个基因座作为进一步研究的候选基因，其中两个以前使用更传统的QTL方法被确定为显著的动脉粥样硬化修改基因座，该方法涉及培育大量的F2小鼠。这项拟议工作的总体目标是确定这些QTL和新发现的QTL背后的动脉粥样硬化易感基因，并评估这些基因的人类同源基因的常见多态是否与心血管疾病有关。我们建议通过在动脉粥样硬化易感品系DBA/2上的apoE缺陷小鼠之间培育F2队列来在电子QTL中确认这些 以及抗动脉粥样硬化的AKR株。对于每只小鼠，将对动脉粥样硬化病变区域进行定量评估，并进行基因组扫描，以便执行传统的QTL分析，以确认电子QTL并确定其他QTL。为了验证每个QTL，将在次要同源品系中评估损伤，在次要同源品系中，一个品系的QTL间隔被培育到另一个品系上。这些次级同源系将被进一步培育以产生重组体，以便将QTL区间精细定位到约1Mb。这一区间内的所有基因都将通过小鼠草稿基因组序列进行鉴定。将使用多种并行方法来识别负责基因，包括表达微阵列、识别 在每个区间的基因中存在菌株特异性多态，并通过在转基因小鼠中过表达来检测候选基因。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.