Substrate stiffness regulates alveolar epithelial cell behavior

描述（由申请人提供）：在急性肺损伤（ALI）或成人呼吸窘迫综合征（ARDS）患者中，受损肺泡上皮的修复紊乱可导致肺纤维化。纤维化与肺实质中富含胶原的细胞外基质的异常积累有关，导致组织僵硬和肺功能的进行性下降。我们将验证纤维化组织诱导肺泡上皮细胞（AEC）沉积富含(3)层粘连蛋白亚基的基质的假设，该亚基通过细胞表面受体糖聚糖和信号支架蛋白plectin起作用，保护AEC免受纤维化环境的有害影响。为了验证这一假设，在目的1中，我们将在正常肺和纤维化肺以及体外维持在不同硬度底物上的AEC中检测(3)层粘连蛋白基质原位沉积。在目标2中，我们将评估？3层粘连蛋白、糖酐和粘连蛋白介导AEC在不同硬度底物上的存活、粘附、迁移、增殖和分化。在Aim 3中，我们将在两种不同的肺部疾病小鼠模型中评估(3)层粘连蛋白的缺失是否会增强纤维化并抑制疾病消退。为此，我们建议使用可诱导的肺特异性(3层粘连蛋白亚基敲除小鼠系。在我们的基因敲除小鼠和对照小鼠中，肺纤维化将通过博来霉素治疗动物或通过气管内注入编码活性TGF-(1)的腺病毒而引发。我们的目标将为急性肺损伤后纤维化的可变发展机制提供新的见解，这是ALI/ARDS患者预后的主要决定因素。公共卫生相关性：在某些肺部疾病中，肺组织变得纤维化和变硬。我们建议分析肺的硬度如何调节其细胞成分的功能。我们的研究结果将为疾病进展的机制提供新的见解，并对未来的治疗具有指导意义。

DESCRIPTION (provided by applicant): In patients with acute lung injury (ALI) or the adult respiratory distress syndrome (ARDS), disordered repair of the injured alveolar epithelium can result in lung fibrosis. Fibrosis is associated with aberrant accumulation of a collagen-rich extracellular matrix in the lung parenchyma that results in tissue stiffness and a progressive decline in lung function. We will test the hypothesis that the tissue in fibrosis induces alveolar epithelial cells (AEC) to deposit matrix enriched in the (3 laminin subunit which functions, via the cell surface receptor dystroglycan and the signaling scaffold protein plectin, to protect AEC from the harmful impact of the fibrotic milieu. To test this hypothesis, in Aim 1, we will assay (3 laminin matrix deposition in situ in normal and fibrotic lungs and in AEC maintained in vitro on substrates of varying stiffness. In Aim 2, we will evaluate the role of ?3 laminin, dystroglycan and plectin in mediating the survival, adhesion, migration, proliferation and differentiation of AEC maintained on substrate of varying stiffness. In Aim 3, we will assess whether the absence of the (3 laminin enhances fibrosis and inhibits disease resolution in two different mouse models of lung disease. In this aim, we propose to use an inducible lung specific (3 laminin subunit knockout mouse line. Lung fibrosis in our knockout and control mice will be initiated by treatment of animals with bleomycin or by the intratracheal instillation of an adenovirus encoding active TGF-(1. Our aims will provide new insights into the mechanisms that underlie the variable development of fibrosis after acute lung injury, a major determinant of outcome in patients with ALI/ARDS. PUBLIC HEALTH RELEVANCE: In certain pulmonary diseases, lung tissue becomes fibrotic and stiffens. We propose to assay how the stiffness of the lung regulates the function of its cellular components. Our results will provide novel insight into the mechanisms of disease progression and has implications for future therapies.