Linking Biological, Optical, and Mechanical Properties in the Airway Mucosa

描述（由申请人提供）：气道上皮损伤发生在吸入有毒物质、感染、插管和慢性重复性疾病（如哮喘）后，影响美国约10%的人口。上皮的创伤修复反应可诱导下层结缔组织的结构和机械性质的变化，这可改变正常肺功能。在支气管哮喘中，随着疾病的进展，气道粘膜的改变变得更加突出，并且与疾病的严重程度、症状和肺功能相关（即，固定气流阻塞）。已知支气管上皮在胚胎发生期间调节肺实质的发育，并且这些信号传导途径可能在慢性炎性疾病（例如哮喘）期间被“重新唤醒”，从而导致病理性组织生长。我们的中心假设是，受伤和发炎的上皮细胞分泌可溶性介质，这些介质以生物活性浓度扩散到下面的基质中，以显著影响基质的机械性能。我们的具体目标是专门解决上皮细胞在调节上皮下基质的机械和光学性质中的作用：1）利用两种物理性质，（压缩和刮擦）和化学（IL-13）损伤，表征对上皮下基质的光学和机械性质的影响; 2）表征光学终点与无细胞和细胞化胶原凝胶两者的机械性质之间的关系，其中胶原含量、微结构和转化生长因子-2被系统地改变; 3）在反复气道上皮损伤的兔模型中量化气管粘膜的光学和机械性质的变化。该提案结合了新的组织工程技术，模仿上皮和固有层的解剖学排列，传统的生物学技术，以评估蛋白质表达，非传统的微创光学技术（多光子激光扫描显微镜和光学相干断层扫描），以评估散装和微观变化的矩阵，和气管上皮损伤的体内模型。这些目标的完成将提供对气道重塑的潜在机制的洞察，并且不仅为气道，而且还为遭受慢性或急性损伤的其他上皮组织（例如，角膜、皮肤）。公共卫生相关性：气道损伤，主要表现为哮喘，是美国最流行的慢性疾病之一。由于导致组织重塑的疾病的慢性重复性质，诊断和管理仍然具有挑战性。该提案旨在了解触发气道粘膜机械和光学特性变化的生物机制之间的联系。研究结果将为药物发现和非侵入性诊断提供平台。

DESCRIPTION (provided by applicant): Airway epithelial injury occurs following inhalation of toxic agents, infection, intubation, and in a chronic repetitive disease such as asthma which impacts approximately 10% of the population in the United States. The wound repair response of the epithelium can induce changes in the structure and mechanical properties of the underlying connective tissue that can alter normal lung function. In bronchial asthma, alterations in the airway mucosa become more prominent as the disease progresses, and are correlated with disease severity, symptoms, and lung function (i.e., fixed airflow obstruction). The bronchial epithelium is known to modulate the development of the lung parenchyma during embryogenesis and these signaling pathways are likely "re- awakened" during chronic inflammatory diseases such as asthma resulting in pathological tissue growth. Our central hypothesis is that the wounded and inflamed epithelium secretes soluble mediators which diffuse into the underlying stroma at biologically active concentrations to significantly influence the mechanical properties of the matrix. Our specific aims are structured to specifically address the role of the epithelium in modulating the mechanical and optical properties of the subepithelial matrix: 1) utilizing both physical (compressive and scrape) and chemical (IL-13) injuries to the normal human bronchial epithelium in vitro, characterize the resulting impact on the optical and mechanical properties of the subepithelial matrix; 2) characterize the relationship between optical endpoints and the mechanical properties of both acellular and cellularized collagen gels in which collagen content, microstructure, and transforming growth factor-2 are systematically altered; 3) quantify changes in the optical and mechanical properties of the tracheal mucosa in a rabbit model of repeated airway epithelial injury. The proposal combines novel tissue engineering techniques which mimic the anatomical arrangement of the epithelium and lamina propria, conventional biological techniques to assess protein expression, non-traditional minimally-invasive optical techniques (multiphoton laser scanning microscopy and optical coherence tomography) to assess bulk and microscopic changes in the matrix, and an in vivo model of tracheal epithelial injury. Completion of these aims will provide insight into the underlying mechanisms of airway remodeling, and provide a platform for non-invasive diagnostics for not only the airway, but other epithelial tissues subject to chronic or acute injury (e.g., cornea, skin). PUBLIC HEALTH RELEVANCE: Airway injury, manifested primarily by asthma, is one of the most prevalent chronic diseases in the United States. Diagnosis and management remain challenging due to the chronic repetitive nature of the disease that leads to tissue remodeling. The proposal seeks to understand the link between the biological mechanisms that trigger changes in the mechanical and optical properties in the airway mucosa. The results should provide a platform for drug discovery and non-invasive diagnostics.