ELASTASES OF HUMAN ALVEOLAR MACROPHAGES

弹性蛋白的降解是糖尿病发病机制中的重要组成部分。 肺气肿及其巨噬细胞参与肺气肿的机制 退化是完全可以理解的。申请人之前的工作， 综上所述，在本应用中，已经证明了肺巨噬细胞 一种高效弹性蛋白酶组织蛋白酶L合成及其摄取 通过一条具有新功能的途径从细胞外微环境 特性是细胞内酶水平的重要决定因素。 进一步描述这种摄取途径的策略是 以及提出的实验，以确定这一作用 其他蛋白水解酶在细胞内积累的途径。第二 这笔赠款的主要目的是描述和识别 另一种弹性分解酶，它既具有 半胱氨酸蛋白酶和一种金属酶。提供的数据演示了 一种或多种酶，其相对分子质量为~22kD，具有最适的酸性pH，是 对人类肺中发现的大部分弹性溶解活动负责 巨噬细胞。进一步的研究表明，这一活性 吸烟者的巨噬细胞中的酶(S)增加了7倍。实验是 建议进一步表征这种酶的调节，以及 对其进行分离和排序。作为一个整体，这些研究将允许 申请者将继续探索肺内蛋白水解酶的调节 巨噬细胞同时发展成为独立的 调查员。

The degradation of elastin is a critical component of the pathogenesis of emphysema and the mechanisms by which macrophages participate in this degradation are completely understood. Prior work by the applicant, summarized in this application, has demonstrated that lung macrophages synthesize cathepsin L, a potent elastase, and that uptake of this enzyme from the extracellular microenvironment by a pathway with novel functional characteristics is a important determinant of intracellular enzyme levels. A strategy for the further characterization of this uptake pathway is presented, as well as proposed experiments to ascertain the role of this pathway in the intracellular accumulation of other proteases. The second major aim of this grant relates to the characterization and identification of a second elastolytic enzyme that has the characteristics of both a cysteine proteinase and a metalloenzyme. Data is presented demonstrating that one or more enzymes, with a MW of ~22 kD with an acidic pH optimum, is responsible for the majority of elastolytic activity seen in human lung macrophages. Further studies demonstrated that the activity of this enzyme(s) is increased 7 fold in smokers' macrophages. Experiments are proposed to further characterize the regulation of this enzyme, as well as to isolate and sequence it. Taken as a whole, these studies will allow the applicant to continue to explore the regulation of proteases in lung macrophages while developing the skills needed to become an independent investigator.