Substrate stiffness regulates alveolar epithelial cell behavior

描述(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，受损的肺泡上皮修复障碍可导致肺纤维化。纤维化与肺实质中富含胶原的细胞外基质异常堆积有关，导致组织僵硬和肺功能进行性下降。我们将验证一种假设，即纤维化中的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，该亚基通过细胞表面受体DystroGan和信号支架蛋白plectin发挥作用，以保护AEC免受纤维化环境的有害影响。为了验证这一假设，在目标1中，我们将在不同硬度的底物上原位检测正常肺和纤维化肺以及体外维持的AEC中层粘连蛋白基质的沉积。在目标2中，我们将评估β3层粘连蛋白、营养不良多糖和凝集素在不同硬度的基质上维持的AEC的存活、黏附、迁移、增殖和分化中的作用。在目标3中，我们将评估在两种不同的肺部疾病小鼠模型中，层粘连蛋白(3)的缺失是否增强了纤维化并抑制了疾病的消退。为此，我们建议使用一种可诱导的肺特异性(3层粘连蛋白亚单位)基因敲除小鼠系。我们的基因敲除和对照小鼠的肺纤维化将通过用博莱霉素治疗动物或通过气管内滴注编码活性转化生长因子-(1)的腺病毒来启动。我们的目标将为急性肺损伤后纤维化的不同发展提供新的见解，急性肺损伤后纤维化的发展是ALI/ARDS患者预后的主要决定因素。与公共卫生相关：在某些肺部疾病中，肺组织变得纤维化和僵硬。我们建议分析肺的僵硬如何调节其细胞成分的功能。我们的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启示意义。

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.