Alveolar Basement Membrane/Cell Interactions in the Lung

描述（由申请人提供）：肺泡区域的上皮细胞容易受到损伤，例如由空气传播的毒物或氧化应激引起的损伤。 损伤后这些细胞更换的中断/延迟会导致肺泡修复错误和不可逆转的功能受损。 在本提案中，我们将证明肺上皮细胞和成纤维细胞之间存在关键的动态关系，这决定了它们对硫酸化细胞外基质（SECM）和生长因子的反应和表达。 这构成了一个动态屏障，由细胞本身修饰，定义了它们的选择性分工，最大化了它们的共同效率，并反映在这些调节因子表达的特定反调节中。 要解决的假设是：肺泡上皮和下面的成纤维细胞之间的硫酸化细胞外基质选择性下调关键调节因子的生成和活性：FGF-1、-2和-7及其衔接分子（FGF受体、FGF结合蛋白和特定的硫酸化ECM）。 这些过程构成了在肺泡正常、增生和疾病状态下调节细胞数量、细胞功能和细胞结构排列的关键旁分泌和近分泌机制。 分离的 AT2 细胞将与成纤维细胞共培养，并通过外源添加或刺激过量生产（增强）或基因/蛋白质表达的选择性抑制/修饰（减少）来修饰干预的硫酸化 ECM 环境。 为了确定控制关键上皮细胞-成纤维细胞相互作用的机制，将通过 DNA 合成、相关信号传导事件和所选基因/蛋白质产物的表达来测量细胞对关键调节生长因子过度表达和生长因子反应接头抑制翻译的反应。 使用腺载体介导的基因转移进行的整体动物研究将确定 FGF-BP 或 syndecan-1 的过度表达是否会改善或改变肺纤维化体内模型中的损伤/修复结果。 这些研究的结果预计将提供必要的信息，以更好地理解体内平衡中基本的细胞-细胞、细胞-ECM关系，以及引导肺部因损伤和/或疾病而发生纤维化变化的发病机制。

DESCRIPTION (provided by applicant): The epithelium of the alveolar region of the lung is susceptible to injury, such as that induced by air-borne toxicants or oxidant stress. Interruption/delay of the replacement of these cells following injury results in faulty repair and irreversibly impaired function in the alveolus. In this proposal, we will show that there exists a critical, dynamic relationship between lung epithelial cells and fibroblasts that dictate their responsiveness to and expression of sulfated extracellular matrices (SECMs) and growth factors. This constitutes a dynamic barrier, modified by the cells themselves, that defines their selective division of labor, maximizes their common efficiency, and is reflected in specific counter-regulation of expression of these modulatory factors. The hypothesis to be addressed is: The sulfated extracellular matrix between alveolar epithelium and underlying fibroblasts selectively down-regulates generation and activity of key regulatory factors: FGF-1, -2, and -7, and their adaptor molecules (FGF-receptors, FGF-binding protein, and specific sulfated ECMs). These processes constitute critical paracrine and juxtacrine mechanisms for regulating cell numbers, cell functions, and cellular architectural arrangement under normal, hyperplastic, and disease states in the alveolus. Isolated AT2 cells will be co-cultured with fibroblasts and the intervening sulfated ECM environment modified by either exogenous addition or stimulated overproduction (enhancement) or selective inhibition/modification of gene/protein expression (reduction). To define the mechanisms that control critical epithelial cell-fibroblast interactions, cellular responses to over expression of key regulatory growth factors and inhibited translation of growth factor response adapters will be measured by DNA synthesis, relevant signaling events, and expression of selected gene/protein products. Whole animal studies using adenovector-mediated gene transfer will determine if over expression of FGF-BP or syndecan-1 improves or alters injury/repair outcomes in an in vivo model of pulmonary fibrosis. Results of these studies are expected to provide essential information needed to better understand basic cell-cell, celI-ECM relationships in homeostasis, as well as the mechanisms that steer the pathogenesis of fibrogenic change in the lung because of injury and/or disease.