IDENTIFICATION AND CHARACTERIZATION OF MATERIALS SECRETED BY CLARA CELLS

克拉拉细胞分泌物质的鉴定和表征

• 批准号: 3941510
• 负责人: G R HOOK
• 金额: --
• 依托单位: NATIONAL INSTITUTE OF ENVIRONMENTAL HEALTH SCIENCES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/3941510
• 关键词: bronchus; cell differentiation; density gradient ultracentrifugation; diagnostic respiratory lavage; gel electrophoresis; genetic translation; granule; growth media; messenger RNA; microsomes; respiratory epithelium; respiratory transplantation; secretion; tissue /cell culture

The functions of the bronchiolar Clara cell are not known although it is generally believed that the cell is secretory. Using a model system, developed in this laboratory, we have identified a low molecular weight protein (Mr 12,500) as the major protein secreted by Clara cells. We have also identified the major secretory a simple procedure for its isolation. Antiserum developed in goats against highly purified Clara cells (purity greater than 90%) has been used to localize Clara cell secretory proteins within the osmiophilic cytoplasmic granules of bronchiolar Clara cells indicating the storage nature of the granules and that secretion of the low molecular weight protein probably occurs via a regulated pathway. We have also isolated mRNA from rabbit lungs and demonstrated that the primary translation product has a molecular weight about 1 kDa larger than the secreted form of the protein. The additional peptide was a signal peptide as indicated by its loss from the molecule when translation of the messenger was performed in the presence of microsomes. These studies identify the major secretory protein of Clara cells as a low molecular weight protein that appears to be stored within the cytoplasmic osmiophilic granules. We have also investigated the differentiative potential of Clara cells by inoculating purified cells into rat trachea denuded of their own epithelia. These trachea were then grafted onto the backs of nude mice and examined periodically for regeneration of epithelium. We have determined that Clara cells can multiply and generate an epithelium which consists of Clara cells and ciliated cells thus establishing the stem cell nature of this bronchiolar cell. Future studies will explore the ability of Clara cells to differentiate into mocous cells using the tracheal graft model and focus on the extracellular function of the low molecular weight secretory protein.

细支气管克拉拉细胞的功能尚不清楚。 尽管人们普遍认为细胞是分泌细胞。vbl.使用 在这个实验室开发的一个模型系统，我们已经确定了一个 低分子量蛋白质(Mr 12,500)为主要蛋白质 由克拉拉细胞分泌。我们还确定了少校 为它的分离分泌一个简单的程序。抗血清 在山羊体内培养抗高度纯化的Clara细胞(纯度 90%以上)已被用于定位Clara细胞分泌 嗜奥斯性胞质颗粒内的蛋白质 细支气管型Clara细胞表明 颗粒与低分子蛋白质分泌 可能是通过一条受调控的途径发生的。我们还分离出了 从兔肺中提取的mRNA，并证明了原始的 翻译产物的分子量要大1 kDa左右 而不是蛋白质的分泌形式。添加的多肽是 一种信号肽，由当它从分子中丢失来表示 信使的翻译是在当面进行的 微粒体。这些研究确定了主要的分泌蛋白 作为一种低分子量蛋白质，它似乎 储存在细胞质中的嗜奥斯性颗粒内。我们有 也研究了Clara细胞的分化潜能 大鼠气管内接种纯化细胞的实验研究 上皮细胞。这些气管随后被移植到 并定期检查裸鼠的再生情况 上皮组织。我们已经确定了Clara细胞可以增殖和 产生由Clara细胞和纤毛组成的上皮 从而确定了该细支气管膜的干细胞性质 手机。未来的研究将探索Clara细胞的能力 利用气管移植模型分化为粘液细胞 关注低分子量的胞外功能 分泌蛋白质。