Genetic analysis of hyperoxia-induced acute lung injury

描述（由申请人提供）：急性肺损伤，包括最严重的形式-急性呼吸窘迫综合征（ARDS），是一种毁灭性的，往往是致命的疾病，可由许多看似无关的直接或间接肺损伤引起。已经测试了数百种与疾病发生或进展相关的蛋白质，以描述它们可能的作用；然而，在确定造成其发病率和死亡率的主要因素方面，几乎没有取得进展。由于在过去十年中使用这种候选基因方法的死亡率变化不大，因此替代策略对于提高我们对急性肺损伤发生和进展的病理生物学的理解至关重要。本研究的目的是利用小鼠急性肺损伤模型来确定与死亡率相关的主要数量性状位点（qtl）。为了获得该建议的初步数据，我们筛选了18种常见近交系小鼠在高氧（>95% O2）下的生存时间，高氧是一种用于诱导急性肺损伤和ARDS的原型剂。鉴定了两种不同生存时间的小鼠模型。首先，C57BL/6J (B)小鼠对高氧诱导的急性肺损伤死亡率敏感，而129X1/SvJ (S)小鼠对高氧诱导的急性肺损伤死亡率更有抵抗力。第二，将抗性S菌株与129P3/J (P)组合，129P3/J (P)是亲缘关系较近但敏感的毒株。对每种小鼠模型产生的后代的初步结果表明，性状遗传模式复杂，包括多基因和其他遗传和表观遗传因素（例如外显率降低、亲代印记和/或线粒体遗传）。S和p源杂交也表明有性连锁。根据这些初步数据，我们假设高氧诱导的急性肺损伤存活是一种数量性状，可以通过使用小鼠近交系进行遗传分析来模拟人类疾病。对于每个小鼠模型，提出了以下三个具体目标：(1)确定整体性状遗传的可能模式（分离分析），并估计对响应有贡献的位点数量；(2)鉴定高氧诱导的backcross和F2小鼠急性肺损伤存活相关的遗传区域（QTL分析）；(3)鉴定与菌株生存差异相关的候选基因和位置候选基因（微阵列分析）。通过这种联合方法，我们希望不仅能深入了解高氧诱导的急性肺损伤的病理，而且还能了解其与其他氧化诱导的急性肺损伤的可能相似之处。拟议的研究为一个可撤消的问题提供了不同的视角，并可能产生迫切需要的宝贵信息，以进一步评估人群中潜在疾病风险和治疗结果的遗传差异。

DESCRIPTION (provided by applicant): Acute lung injury, including the most severe form - acute respiratory distress syndrome (ARDS), is a devastating and, too often-times, lethal condition that can result from numerous seemingly unrelated direct or indirect pulmonary insults. Hundreds of proteins associated with the initiation or progression of the disease have been tested to delineate their possible role(s); however, little progress has been made to identify the key players responsible for its morbidity and mortality. Because mortality rates have changed little over the last decade using this candidate-gene approach, alternative strategies are essential to advance our understanding of the pathobiology of acute lung injury development and progression. The goal of this research is to use mouse models of acute lung injury to identify the major quantitative trait loci (QTLs) linked to mortality. To gain preliminary data for this proposal 18 common inbred mouse strains were screened for survival time in hyperoxia (>95% O2), a prototypic agent used to induce acute lung injury and ARDS. Two mouse models of differential survival time were identified. First, C57BL/6J (B) mice are sensitive, whereas 129X1/SvJ (S) mice are much more resistant to hyperoxia-induced acute lung injury mortality. Second, the resistant S strain was combined with 129P3/J (P), a closely related, but sensitive sub strain of the 129 line. Initial results with offspring generated for each mouse model suggested a complex mode of trait inheritance, including multiple genes and other genetic and epigenetic factor(s) (e.g., decreased penetrance, parental imprinting, and and/ or mitochondrial inheritance). S and P-derived crosses also suggested sex linkage. From these preliminary data, we hypothesize that hyperoxia-induced acute lung injury survival is a quantitative trait that is amenable to genetic analysis using inbred strains of mice to model the human disease. For each mouse model, the following three specific aims are proposed: (1) determine the likely mode of overall trait inheritance (segregation analysis) and estimate the number of loci contributing to the response; (2) identify genetic regions linked to hyperoxia-induced acute lung injury survival in backcross and F2 mice (QTL analysis) generated from strains of each model; and (3) identify candidate and positional candidate genes associated with the strain survival differences (microarray analysis). With this combined approach, we expect to gain insight into not only the pathology of hyperoxia-induced acute lung injury, but also the possible similarities to other oxidant-induced acute lung injuries. The proposed studies offer a different perspective to a retractable problem and could yield valuable information urgently needed to further assess genetic differences underlying disease risks and therapeutic outcomes in the population.