Gene Expression Changes Associated with the Airway Wall Response to Injury

BackgroundUnderstanding the way in which the airway heals in response to injury is fundamental to dissecting the mechanisms underlying airway disease pathology. As only limited data is available in relation to the in vivo characterisation of the molecular features of repair in the airway we sought to characterise the dynamic changes in gene expression that are associated with the early response to physical injury in the airway wall.Methodology/Principal FindingsWe profiled gene expression changes in the airway wall using a large animal model of physical injury comprising bronchial brush biopsy in anaesthetised sheep. The experimental design featured sequential studies in the same animals over the course of a week and yielded data relating to the response at 6 hours, and 1, 3 and 7 days after injury. Notable features of the transcriptional response included the early and sustained preponderance of down-regulated genes associated with angiogenesis and immune cell activation, selection and differentiation. Later features of the response included the up-regulation of cell cycle genes at d1 and d3, and the latter pronounced up-regulation of extracellular matrix-related genes at d3 and d7.Conclusions/SignificanceIt is possible to follow the airway wall response to physical injury in the same animal over the course of time. Transcriptional changes featured coordinate expression of functionally related genes in a reproducible manner both within and between animals. This characterisation will provide a foundation against which to assess the perturbations that accompany airway disease pathologies of comparative relevance.背景：阐明气道损伤后的修复通路，是解析气道疾病病理底层机制的核心基础。鉴于目前针对气道修复分子特征的体内（in vivo）表征相关研究数据较为匮乏，本研究旨在刻画气道壁物理损伤早期应答过程中伴随的基因表达动态变化。 方法与主要结果：本研究采用麻醉绵羊的支气管刷检术构建物理损伤大动物模型，对气道壁的基因表达变化开展了基因表达谱分析。实验设计采用同一动物的时序采样方案，于损伤后6小时、1天、3天及7天四个时间点采集样本，获取对应损伤应答数据。转录应答的显著特征包括：早期且持续富集的与血管生成（angiogenesis）、免疫细胞激活、筛选及分化相关的下调基因；损伤应答的后期特征则体现为：第1天及第3天细胞周期相关基因的上调，以及第3天、第7天细胞外基质（extracellular matrix）相关基因的显著上调。 结论与意义：本研究实现了同一动物体内气道壁物理损伤应答的时序追踪。转录组变化呈现功能相关基因的协同表达模式，且在个体内及个体间均具备可重复性。本研究的表征结果将为评估具有比较研究价值的气道疾病病理伴随的分子扰动提供重要基础。