Genetic and Longitudinal Analysis of Airway Remodeling

摘要 哮喘是一种慢性肺部疾病，导致25岁以上的人气道狭窄和高反应性。 数百万美国人尽管哮喘的吸入性糖皮质激素治疗是可行的， 需求依然存在。气道的细胞和组织组成的变化，称为气道重塑， 预计会影响哮喘患者肺功能的降低。这些减少无法完全解决， 可用的治疗方法，并可能导致致命的哮喘发作中看到的气道粘液阻塞。虽然 许多遗传和环境因素导致哮喘风险和严重程度，确定了 由于不能从大量的肺组织中取样， 受影响的个人和跟踪重塑随着时间的推移。阐明气道重塑的分子调节因子 是更全面了解哮喘发病机制的必要步骤， 有效的治疗方法。 该项目将询问慢性气道重塑的遗传和转录调控， 过敏原诱导的过敏性气道疾病小鼠模型。这些分析将有力地定义 重塑表型之间，确定新的治疗靶点，并跟踪重塑的发展， 进展在慢性暴露于屋尘螨（HDM）过敏原后，小鼠出现气道特征， 反映人类疾病的重塑，包括杯状细胞化生、上皮下纤维化和平滑肌细胞增生。 肌肉增厚我将研究这些重塑表型的机制，通过一个 使用协作杂交（CC）小鼠群体的无偏全基因组方法。CC是一个小组， 重组近交系，其中每个系的基因组代表八个创始菌株的独特嵌合体 包括五个经典的近交系和三个野生衍生的菌株， 多态性这种遗传变异导致菌株间的高表型变异性，使得有可能 使表型和基因型变异之间的关联，除了观察菌株与新的 表型我将量化30个慢性HDM治疗的CC株的气道重塑表型， 估计遗传变异对重塑的贡献，这是更好地了解气道的重要一步 重塑驱动程序，这在人类身上还不可能。此外，我将执行整个转录组 测序气道组织，并使用生物信息学方法来鉴定候选转录调节因子， 气道重塑表型，特别关注粘液分泌过多。这些候选监管机构和 其他基因将在慢性HDM暴露的时间过程中进行评估， 重塑的进展。综上所述，本研究的结果将进一步加深我们对气道的认识 重塑机制以及重塑如何随着时间的推移而发展，为 确定哮喘的新靶向治疗方法。

ABSTRACT Asthma is a chronic lung condition that causes airway narrowing and hyperresponsiveness in over 25 million Americans. Despite available inhaled corticosteroid treatments for asthma, significant unmet therapeutic needs remain. Changes in the cellular and tissue composition of the airways, referred to as airway remodeling, are predicted to influence reduced lung function in asthmatics. These reductions cannot be fully resolved with available therapeutics and can lead to mucus occlusion of the airways seen in fatal asthma attacks. Although numerous genetic and environmental factors contribute to asthma risk and severity, identifying the drivers of airway remodeling remains challenging due to the inability to sample lung tissue from a large number of affected individuals and track remodeling over time. Elucidating the molecular regulators of airway remodeling is a necessary step toward a more comprehensive understanding of asthma pathogenesis required to design effective therapeutics. This project will interrogate the genetic and transcriptional regulation of airway remodeling in a chronic allergen-induced mouse model of allergic airway disease. These analyses will robustly define the relationships between remodeling phenotypes, identify novel therapeutic targets, and track remodeling development and progression. Upon chronic exposure to house dust mite (HDM) allergen, mice develop features of airway remodeling that mirror human disease, including goblet cell metaplasia, subepithelial fibrosis, and smooth muscle thickening. I will investigate the mechanisms underlying these remodeling phenotypes through an unbiased genome-wide approach with the Collaborative Cross (CC) mouse population. The CC is a panel of recombinant inbred lines where the genome of each line represents a unique mosaic of eight founder strains including five classical inbred and three wild-derived strains varying by 45 million single nucleotide polymorphisms. This genetic variation results in high phenotypic variability across strains, making it possible to make associations between phenotypic and genotypic variation, in addition to observing strains with novel phenotypes. I will quantify airway remodeling phenotypes in 30 CC strains chronically treated with HDM and estimate the contribution of genetic variation to remodeling, an important step in better understanding airway remodeling drivers that has not yet been possible in humans. Furthermore, I will perform whole transcriptome sequencing of airway tissue and use bioinformatic approaches to identify candidate transcriptional regulators of airway remodeling phenotypes with a specific focus on mucus hypersecretion. These candidate regulators and other genes will be evaluated in a time course of chronic HDM exposure that tracks the initiation and progression of remodeling. In summary, the results of this proposal will further our understanding of airway remodeling mechanisms and how remodeling is developed over time, providing a significant foundation for identifying new targeted therapeutics for asthma.!