MECHANISMS OF HUMAN LUNG HYPERSENSITIVITY REACTIONS

该项目的长期目标是更好地了解 人类肺超敏性疾病的机制和控制 和哮喘。 研究将集中在肺的中央细胞 人肺肥大细胞（HLMC）。 HLMC， 由于其解剖定位， 刺激后的化学介质，以及这些介质的作用 细胞和组织靶点上的介质，可以产生 这些疾病的病理生理表现：气道 收缩水肿和分泌过多 这些研究涉及将人肺酶促分散到 单细胞悬液，通过淘洗分离HLMC， 通过分级梯度浮选， 基于其直径的功能不同的亚群， 密度，分别。 密度阶跃还导致 直径分离的HLMC的纯化。 通过利用 直径和密度后发现典型的组织化学轮廓 分离，我们最近还开发了分离方法， HLMC亚群类似于组织化学上不同的 在啮齿类动物中经典描述的亚群。 一旦分离，HLMC亚群将用 超微结构、介质含量和释放 （包括最近发现的肥大细胞弹性蛋白酶），以及 对相关触发刺激的敏感性。 这些刺激因素包括 一种新描述的肺泡巨噬细胞源性释放因子。 此外，亚群对药理学的选择性反应性 将检查释放的调节。 待测试剂 包括β-肾上腺素能激动剂、花生四烯酸抑制剂 代谢、膜胆固醇结合剂和胆固醇 生物合成抑制剂 膜胆固醇和磷脂在 将通过定量分析在纯化的HLMC中探索释放 胆固醇和磷脂周转率的测量， 激活-分泌 HLMC释放的新机制 抑制，通过操纵膜脂质微- 环境，也将进行研究。

This project's long term objective is a better understanding of the mechanisms and control of human lung hypersensitivity disorders and asthma. Studies will focus on the central cell of lung hypersensitivity, the human lung mast cell (HLMC). The HLMC, by virtue of its anatomic localization, elaboration of potent chemical mediators upon stimulation, and the effects of these mediators on cell and tissue targets, can produce the pathophysiologic manifestations of these disorders: airway constriction, edema, and hypersecretion. The studies involve enzymatically dispersing human lung into a single cell suspension, and separating HLMC by elutriation and flotation through step-gradients into morphologically and functionally distinct subpopulations based on their diameters and densities, respectively. The density-step also results in purification of diameter separated HLMC. By taking advantage of typical histochemical profiles found after diameter and density separations, we have also recently developed methods to isolate HLMC subpopulations akin to the histochemically distinct subpopulations classically described in the rodent. Once isolated, HLMC subpopulations will be examined with respect to ultrastructure, content and release of mediators (including a recently discovered mast cell elastase), and sensitivities to relevant triggering stimuli. These stimuli include a newly described alvolar macrophage-derived releasing factor. Also, selective responsiveness of subpopulations to pharmacologic modulation of release will be examined. The agents to be tested include B-adrenergic agonists, inhibitors of arachidonic acid metabolism, membrane cholesterol binders, and cholesterol biosynthesis inhibitors. The crucial role of membrane cholesterol and phospholipids in release will be explored in purified HLMC through quantitative measurements of cholesterol and phospholipid turnover during activation-secretion. Novel mechanisms of HLMC release inhibition, through manipulation of the membrane lipid micro- environment, will also be studied.