ALVEOLAR HOMEOSTASIS OF SURFACTANT LIPIDS AND PROTEINS

我们的假设是表面蛋白与磷脂相互作用并参与表面活性剂稳态的调节。该项目的目标是表征表面活性剂的脂质和蛋白质成分从II型细胞分泌到肺泡清除、再循环和分解代谢的正常形式。表面活性剂的正常放射性标记脂质和蛋白质成分将用于识别在空气中所采取的形式。平行实验将用于研究表面活性剂组分如何通过表面活性剂的形式转化在体外移动。表面活性剂蛋白成分SP-A、SP-B和SP-C对体外表面活性剂形式转化和表面活性剂功能的重要性和影响将通过缺乏或表面活性剂蛋白表达水平异常的转基因小鼠进行评估。表面活性剂组分从空气空间的清除，回收和/或分解代谢将使用双棕榈酰磷脂酰胆碱和表面活性剂蛋白质的类似物进行量化，其中残余的碳水化合物加合物不被分解代谢。II型细胞、Clara细胞和巨噬细胞对表面活性剂稳态的相对重要性将被量化，对表面活性剂成分运输重要的亚细胞器将被用共聚焦显微镜鉴定。了解正常的表面活性物质稳态将使我们对损伤后肺功能障碍有新的认识。

Our hypothesis is that the surface proteins interact with the phospholipids and participate in the regulation of surfactant homeostasis. The goals of this project are to characterize the normal forms assumed by the lipid and protein components of surfactant from secretion by type II cells to alveolar clearance, recycling and catabolism. Normal radiolabeled lipid and protein components of surfactant will be used to identify the forms taken in the airspace by which component in vivo. Parallel experiments will be used to study how the surfactant components move through the form conversions of surfactant in vitro. The importance to and effects of the surfactant protein components SP-A, SP-B, and SP-C on surfactant form conversions in vitro and surfactant function will be evaluated using transgenic mice that are deficient or have abnormal levels of expression of the surfactant proteins. Surfactant component clearance from the airspaces, and recycling and/or catabolism will be quantified using an analog of dipalmitoylphosphatidylcholine and surfactant proteins with residualizing carbohydrate adducts that are not catabolized. The relative importance of type II cells, Clara cells and macrophages to surfactant homeostasis will be quantified, and subcellular organelles important to surfactant component trafficking will be identified using confocal microscopy. Understanding normal surfactant homeostasis will permit new insights into lung dysfunction with injury.