Cellular and molecular biology of lung surfactant

描述(由申请人提供)： 此应用程序要求为当前处于第30年的计划项目提供五年的额外支持。该项目的主题是肺表面活性物质系统的细胞和分子生物学。假设表面活性物质的细胞周期是通过控制脂肪和蛋白质的合成，在分泌细胞器中包装，调节和结构性分泌，细胞重摄取，以及细胞内对内吞的脂肪和蛋白质成分的处理来调节的。这一假设将通过5个持续的项目进行研究。项目1将评估SP-A与肺泡II型细胞的相互作用，重点是受体介导的SP-A和DPPC的摄取以及SP-A进入板层小体的途径。本项目为P63作为一种生物相关的SP-A受体提供了新的信息。项目2将侧重于ABCA3的分子和功能研究，ABCA3是一种板层体膜蛋白，最初由该计划描述，现在已知对表面活性物质的加工至关重要。由于项目负责人已调往另一所大学，项目3已中止。项目4的重点是表面活性物质相关基因的基因表达调控，重点是TTF调控的基因。该项目开发了一种体外激素反应模型系统，用于研究II型细胞的分化。该项目将专注于板层小体相关蛋白、ABCA3和LAMP的基因调控。项目5的重点是使用各种独特的免疫试剂在细胞内处理SP-C，以确定将初级翻译产物转化为成熟蛋白质的亚细胞位置。该项目已经确定了一种由于SP-C的错误处理而导致侵袭体形成的新途径，并将评估导致肺纤维化综合征的后续细胞损伤的机制。项目6将继续研究过氧化还蛋白6，这是一种由该计划鉴定的新型溶酶体型磷脂酶A2。这种PLA2负责DPPC被II型细胞内化后的降解，也是通过反应途径合成PC所必需的。这5个项目由一个提供腺病毒载体构建和重组蛋白的分子核心、一个为共聚焦荧光成像提供支持的成像和形态核心、包括免疫金定位和形态计量分析的电子显微镜、一个提供人、大鼠和小鼠颗粒肺细胞原代培养的细胞培养核心和一个管理核心提供支持。这些项目和核心形成了一个紧密联系的单元，在研究人员和项目之间进行了广泛的互动，所有这些项目都侧重于了解肺表面活性物质系统的细胞和分子生物学的共同目标，目的是加强表面活性物质相关疾病的治疗。

DESCRIPTION (provided by applicant): This application requests five years of additional support for a Program Project that is currently in year 30. The theme for the program is cellular and molecular biology of the lung surfactant system. The hypothesis is that the surfactant cell cycle is regulated through control of lipid and protein synthesis, packaging in secretory organelles, regulated and constitutive secretion, cellular reuptake, and intracellular processing of endocytosed lipid and protein components. This hypothesis will be studied through 5 continuing projects. Project 1 will evaluate the interaction of SP-A with alveolar type II cells with emphasis on receptor-mediated uptake of SP-A and DPPC and the pathways for routing of SP-A to lamellar bodies. This project provides novel information on P63 as a biologically-relevant SP-A receptor. Project 2 will focus on molecular and functional studies of ABCA3, a lamellar body membrane protein that was originally described by this program and that is now known to be essential for surfactant processing. Project 3 has been discontinued as the project leader has relocated to another university. Project 4 has as its focus the regulation of gene expression for surfactant-related genes with emphasis on genes regulated by TTF. This project has developed an in vitro hormonally responsive model system for study of type II cell differentiation. The project will focus on regulation of genes for the lamellar body relevant proteins, ABCA3 and LAMPS. Project 5 has as its focus the intracellular processing of SP-C using a variety of unique immunological reagents to identify subcellular sites for conversion of the primary translation product to the mature protein. This project has identified a novel pathway to aggresome formation due to misprocessing of SP-C and will evaluate the subsequent mechanisms for cell injury that result in a lung fibrosis syndrome. Project 6 will continue study of perioxiredoxin 6, a novel lysosomal type phospholipase A2 that was identified by this program. This PLA2 is responsible for DPPC degradation following internalization by type II cells and is also required for PC synthesis by the reacylation pathway. The 5 projects are supported by a molecular core that will provide adenovector constructs and recombinant proteins, an imaging and morphology core which provides support for confocal fluorescence imaging, electron microscopy including immunogold localization, and morphometric analysis, a cell culture core that provides primary cultures of human, rat and mouse granular pneumocytes, and an administrative core. These projects and cores form a cohesive unit with extensive interactions between investigators and projects, all focused on the common aim to understand the cellular and molecular biology of the lung surfactant system with the goal of enhancing the treatment for surfactant-related diseases.