BRONCHIOLAR CLARA CELLS: A ROLE IN TYPE 2 CELL FUNCTION

肺的无纤毛细支气管上皮(Clara)细胞 在生理方面仍然是一个很差的特征细胞 在呼吸道中的作用。澄清克拉拉的一个主要障碍 细胞在肺中的功能意义是最大的困难 在获得足够数量的这些电池以用于 学习。在目前的资助期内，我们的实验室 开发了解决此问题的独特方法，方法是建立和 乙基亚硝脲(ENU)诱导的小鼠肺的特征 腺瘤模型，其细胞具有大部分结构和已知 生化特征归因于正常小鼠克拉拉细胞。 这些包括与正常小鼠一致的超微结构特征 增强型β-肾上腺素能分泌调节的Clara细胞 混合功能氧化酶活性，独特的凝集素结合模式和 与正常的Clara细胞有共同抗原的初步证据。 对这一模型的形态研究清楚地表明 细胞与细胞之间的相互作用的发生 瘤旁的腺瘤和肺泡2型细胞。 具体地说，2型细胞被刺激积累了大量的 大量的表面活性物质。此类型2单元格 仅在与Clara细胞腺瘤有关的改变和 似乎与年龄和肿瘤的大小直接相关。 这项经修订的更新建议所详述的研究是为 为了检验细支气管克拉拉细胞有一个 通过定义与肺泡2型细胞的功能相互作用 通过产物调控2型细胞表面活性物质代谢(S) 由Clara细胞合成和分泌。 描述了检验这一假说的三种主要方法。 第一个是建立体外系统，允许更多的 假设的细胞-细胞相互作用的对照研究。这 将通过使用新鲜分离的肺泡2型来实现 将与Clara共培养的细胞或A549细胞系 从ENU诱导的肺腺瘤中分离出细胞。 第二种方法将使用另一种体内生物检测方法 克拉拉细胞分泌产物(S)胸膜腔内注射的疗效观察 将Clara细胞肿瘤和/或细胞植入新生儿或 免疫缺陷的裸鼠。这一模式将减少一些 我们对第二型脑实质可能改变的担忧 细胞受到原始致癌物质的暴露。 最后，我们打算用生化方法分离、提纯和 描述克拉拉细胞分泌产物的组成(S) 并且，使用我们现有的抗Clara细胞抗原的血清，来确定 分泌物的抗原性、分子和功能特性 物质。 我们的小鼠肺Clara细胞腺瘤模型在这些方面的应用 长期目标提供了一种新的独特的方法来定义 Clara细胞在生理和病理条件下的作用 阿龙。

The nonciliated bronchiolar epithelial (Clara) cell of the lung remains a poor characterized cell with respect to its physiologic role in the airway. A major barrier to elucidation of the Clara cell's functional significance in the lung is the great difficulty encountered in obtaining sufficient quantities of these cells for study. During the current grant period, our laboratory has developed a unique approach to this problem by establishing and characterizing an ethylnitrosourea-induced (ENU) murine lung adenoma model, whose cells possess most of the structural and known biochemical features attributed to the normal mouse Clara cell. These include ultrastructural features consistent with normal mouse Clara cells, beta-adrenergic regulation of secretion, enhanced mixed function oxidase activity, unique lectin binding patterns and preliminary evidence of shared antigens with normal Clara cells. Morphological investigations of this model clearly indicated the occurrence of a cell-cell interaction between the Clara cells of the adenoma and alveolar Type 2 cells adjacent to the tumors. Specifically, the Type 2 cells were stimulated to accumulate large quantities of surfactant-like material. This Type 2 cell alteration only occurred in relation to Clara cell adenomas and appeared directly related to age and size of the tumors. The studies detailed in this revised renewal proposal are designed to test the hypothesis that the bronchiolar Clara cell has a defined functional interaction with alveolar Type 2 cells by modulating Type 2 cell surfactant metabolism via product(s) synthesized and secreted by Clara cells. Three major approaches to testing this hypothesis are described. The first is to establish an in vitro system to allow more controlled studies of the postulated cell-cell interactions. This will be accomplished by using freshly isolated alveolar Type 2 cells or the A549 cell line that will be cocultured with Clara cells isolated from ENU-induced pulmonary adenomas. The second approach will use an alternative in vivo bioassay for the effects of Clara cell secretory product(s) using pleural implants of Clara cell tumors and/or cells in newborn or immunologically deficient nude mice. This model will reduce some of our concerns over possible alteration of parenchymal Type 2 cells by the original carcinogenic exposure. Finally, we intend to isolate, purify and biochemically characterize the composition of the Clara cell secretory product(s) and, using our existing antisera to Clara cell antigen, to define the antigenic, molecular, and functional character of the secretory substances. The application of our mouse lung Clara cell adenoma model to these long range goals offer a new and unique approach to define the Clara cell role in physiological and pathological conditions in the lung.