ALBUMIN TRANSPORT BY THE TRACHEAL EPITHELIUM

气管上皮的白蛋白运输

• 批准号: 2224141
• 负责人: Mark E Deffebach
• 金额: $ 13.2万
• 依托单位: OREGON HEALTH & SCIENCE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-01-01 至 1997-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2224141
• 关键词: adrenergic agents; affinity chromatography; albumins; antimitotics; bovine serum albumin; cholinergic agents; colchicine; dextrans; endocytosis; fluorimetry; forskolin; intracellular transport; laboratory rabbit; lysosomes; membrane fusion; microtubules; neurohormones; prostaglandins; protein degradation; protein transport; receptor; respiratory epithelium; secretion; substance P; tissue /cell culture; trachea; vasoactive intestinal peptide; vesicle /vacuole

The long term objectives of this proposal are to understand the mechanisms and regulation of albumin transport across the tracheal epithelium. Albumin is a major protein constituent of the airways lining fluid and has many important properties and functions. These include anti-oxidant and non-specific binding properties, participation in lipid and drug transport, and having profound reversible effects on the physical properties of airway mucus. Despite these important effects, it is generally held that albumin reaches, and leaves the airspaces by purely diffusive mechanisms. Recent studies however, suggest that albumin content in the airways may be highly regulated, and that this regulation involves active transport mechanisms. the alterations in airways albumin content seen in a wide range of airways diseases may reflect abnormalities in these transport processes. these studies will first evaluate albumin and dextran movement in both the serosa to mucosa direction (secretion), and in the opposite direction (absorption) in the intact in-vitro rabbit trachea. The effect of a range of agonists on bidirectional transport will be determined. these results will then be compared to bidirectional albumin and dextran movement across a confluent monolayer of rabbit tracheal epithelial cells in primary culture. The same agonists will be used, and the validity of the tissue culture system for the study of macro-molecular transport determined. Using this system, several mechanisms of albumin transport will be explored. The hypothesis that albumin transport involves specific albumin receptors with endocytotic vesicles and microtubular based transcytosis which may include fusion with lysosomes will be tested. The role of vesicular transport will be assessed by determining the temperature dependence of transport. The participation of the microtubular network determined by pre-treatment with the microtubule-disrupting agents nocodazole and colchicine. The specificity of the transport mechanisms and presence of albumin receptors will be assessed by studying the saturation kinetics of transport and the degree of specific albumin binding on the epithelial surface. Lastly, possible fusion with lysosomes will be sought by looking for degradation of albumin during transport with column chromatography.

该提案的长期目标是了解 白蛋白跨气管转运的机制和调节 上皮。 白蛋白是气道内壁的主要蛋白质成分 流体并具有许多重要的特性和功能。 这些包括 抗氧化和非特异性结合特性，参与脂质 和药物运输，并对 气道粘液的物理特性。 尽管有这些重要影响， 通常认为白蛋白到达并离开空域的时间为 纯粹的扩散机制。 然而最近的研究表明 呼吸道中的白蛋白含量可能受到严格管制，并且这 调节涉及主动运输机制。 的改变 在多种气道疾病中发现的气道白蛋白含量可能 反映这些运输过程中的异常情况。 这些研究将 首先评估白蛋白和葡聚糖在浆膜到粘膜中的运动 方向（分泌）和相反方向（吸收） 完整的体外兔气管。 一系列激动剂的作用 双向传输将被确定。 这些结果将是 与白蛋白和葡聚糖跨汇合体的双向运动相比 原代培养的单层兔气管上皮细胞。 这 将使用相同的激动剂，以及组织培养系统的有效性 用于大分子运输研究的测定。 使用这个 系统，将探索白蛋白运输的几种机制。 这 白蛋白转运涉及特定白蛋白受体的假设 具有内吞囊泡和基于微管的转胞吞作用，这可能 包括与溶酶体的融合将被测试。 囊泡的作用 将通过确定温度依赖性来评估运输 运输。 微管网络的参与由 用微管破坏剂诺考达唑和 秋水仙碱。 运输机制的特殊性和存在 将通过研究饱和动力学来评估白蛋白受体 运输和特异性白蛋白在上皮细胞上结合的程度 表面。 最后，将寻求与溶酶体的可能融合 寻找柱运输过程中白蛋白的降解情况 色谱法。