MECHANISMS OF HUMAN LUNG HYPERSENSITIVITY REACTIONS

这个项目的长期目标是更好地理解 人类肺过敏性疾病的发病机制及防治 还有哮喘。研究将集中在肺的中央细胞上 人肺肥大细胞(HLMC)的超敏反应。HLMC， 凭借其解剖定位，阐述了 化学介体对刺激的影响，以及它们的影响 细胞和组织靶标上的介体，可以产生 这些疾病的病理生理表现：呼吸道 收缩、浮肿和过度分泌。 这些研究涉及通过酶法将人肺分散成 单细胞悬浮液；淋洗分离HLMC； 浮选通过阶梯状梯度进入形态和 基于其直径和功能的不同的子群体 密度分别为。密度阶跃还导致 直径分离的HLMC的纯化。通过利用 直径和密度后发现的典型组织化学图谱 除了分离，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 啮齿动物中经典描述的亚群。 一旦分离，HLMC亚群将用 关于介质的超微结构、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。这些刺激包括 一种新的肺泡巨噬细胞衍生释放因子。 此外，亚群对药物的选择性反应性 将研究释放的调制。被检测的试剂 包括B-肾上腺素能激动剂、花生四烯酸抑制剂 新陈代谢、膜胆固醇结合剂和胆固醇 生物合成抑制剂。 膜胆固醇和磷脂在动脉粥样硬化中的重要作用 将通过定量的方法在纯化的HLMC中探索释放 胆固醇和磷脂周转率的测定 激活-分泌。HLMC释放的新机制 抑制，通过操纵膜脂微米- 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.