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

描述(申请人提供)：呼吸道上皮损伤发生在吸入有毒物质、感染、插管以及影响美国约10%人口的慢性反复疾病(如哮喘)中。上皮的创伤修复反应可以引起底层结缔组织的结构和机械性能的变化，从而改变正常的肺功能。在哮喘中，随着疾病的进展，呼吸道粘膜的改变变得更加明显，并与疾病的严重程度、症状和肺功能(即固定的气流阻塞)相关。已知支气管上皮在胚胎发育期间调节肺实质的发育，这些信号通路可能在慢性炎症性疾病(如哮喘)导致病理性组织生长时被重新唤醒。我们的中心假设是，损伤和炎症的上皮细胞分泌可溶性介质，这些介质以生物活性的浓度扩散到基质中，从而显著影响基质的机械性能。我们的具体目标是专门针对上皮在调节上皮下基质的机械和光学特性中的作用：1)利用体外培养的正常人支气管上皮，利用物理(压缩和擦伤)和化学(IL-13)损伤，表征其对上皮下基质光学和力学特性的影响；2)表征光学终点与无细胞和细胞化的胶原凝胶的机械特性之间的关系，其中胶原含量、微观结构和转化生长因子-2被系统地改变；3)在反复呼吸道上皮损伤的兔模型中，量化气管黏膜的光学和机械特性的变化。该方案结合了模拟上皮和固有层解剖排列的新组织工程技术，评估蛋白质表达的常规生物学技术，评估基质中大量和微观变化的非传统微创光学技术(多光子激光扫描显微镜和光学相干断层扫描)，以及气管上皮损伤的活体模型。这些目标的完成将有助于深入了解呼吸道重塑的潜在机制，并为非侵入性诊断提供平台，不仅适用于呼吸道，还适用于其他遭受慢性或急性损伤的上皮组织(如角膜、皮肤)。公共卫生相关性：呼吸道损伤，主要表现为哮喘，是美国最常见的慢性病之一。由于疾病的慢性重复性质，导致组织重塑，诊断和治疗仍然具有挑战性。该提案试图了解触发呼吸道粘膜机械和光学特性变化的生物学机制之间的联系。这一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.