ELASTASES OF HUMAN ALVEOLAR MACROPHAGES

弹性蛋白的降解是一个重要组成部分的发病机制， 肺气肿和巨噬细胞参与其中的机制 退化完全可以理解。 申请人之前的工作， 在本申请中总结的，已经证明肺巨噬细胞 合成组织蛋白酶L，一种有效弹性蛋白酶，以及这种酶的摄取 从细胞外微环境的途径，具有新的功能 特性是细胞内酶水平的重要决定因素。 进一步表征该摄取途径的策略是 提出，以及提出的实验，以确定这一作用， 其他蛋白酶的细胞内积累途径。 第二 该补助金的主要目的涉及表征和识别 第二种弹性蛋白分解酶，其具有两种弹性蛋白分解酶的特征， 半胱氨酸蛋白酶和金属酶。 数据显示 一种或多种具有约22 kD的MW和酸性pH最适值的酶， 负责在人肺中观察到的大多数弹性蛋白溶解活性 巨噬细胞 进一步的研究表明， 在吸烟者的巨噬细胞中酶增加7倍。 实验 建议进一步表征这种酶的调节，以及 分离并测序。总的来说，这些研究将使 申请人继续探索肺中蛋白酶的调节 巨噬细胞，同时发展成为一个独立的 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.