SURFACTANT RECYCLING IN TYPE II PNEUMOCYTES OF LUNG

最近发现肺表面活性物质磷脂 分子在肺泡亚相内的功能区室之间移动 包括表面活性剂广泛再循环到II型 肺细胞 已经有证据表明， 肺泡亚相，催化磷脂在 人造膜 本提案中概述的项目是针对 在确定这种蛋白质是否是正常的分泌成分时， 以及这种蛋白质是否可以催化 将表面活性剂磷脂重新并入II型 用于回收的肺细胞。 将使用弹性蛋白酶从大鼠肺中分离II型肺细胞。 的 将刺激单层培养物中的细胞分泌表面活性剂， 将检查培养基的磷脂转移活性。 其他 实验将包括将分离的II型肺细胞在 悬浮培养物与纯化磷脂转移蛋白 灌洗材料。 将使用各种组成的囊泡作为供体 膜和转移过程的性质和特异性， II型肺泡细胞测定。 磷脂运动控制机制的阐明 肺的不同功能区室之间的相互作用是至关重要的， 了解并最终操纵肺表面活性物质系统。 对肺泡亚时相蛋白的作用有一个清楚的认识， 在开发出功能齐全的人造表面活性剂之前，

It has become apparent recently that pulmonary surfactant phospholipid molecules move between functional compartments within the alveolar subphase of the lung, including extensive recycling of surfactant to the type II pneumocytes. Evidence has been obtained for the existence of a protein in the alveolar subphase that catalyzes the transfer of phospholipids between artificial membranes. The projects outlined in this proposal are directed at determining whether or not this protein is a normal secretory component of type II pneumocytes and whether or not this protein can catalyze the reincorporation of surfactant phospholipids back into the type II pneumocyte for recycling. Type II pneumocytes will be isolated from rat lungs using elastase. The cells in monolayer culture will be stimulated to secrete surfactant and the medium will be examined for phospholipid transfer activity. Other experiments will involve incubation of isolated type II pneumocytes in suspension culture with a purified phospholipid transfer protein from lavage material. Vesicles of various composition will be used as donor membranes and the nature and specificity of the transfer process to the type II pneumocyte determined. An elucidation of the mechanisms controlling the movement of phospholipids between the various functional compartments of the lung is essential to understanding and eventually manipulating the pulmonary surfactant system. A clear understanding of the role of alveolar subphase proteins may be required before a fully functional artificial surfactant can be developed.