ROLE OF MAST CELL PROTEASES IN AIRWAY INFLAMMATION

肥大细胞储存和分泌的主要蛋白质是蛋白水解酶。这个 其中最丰富的是类胰蛋白酶，一种类似胰酶的丝氨酸蛋白酶，它可以 几乎由所有的肺和呼吸道肥大细胞和抵抗剂合成 释放后循环中的抗蛋白水解酶使其失活。近期工作 破译了狗和人的类胰蛋白酶的一级结构，发现 人类胰蛋白酶基因的新内含子-外显子组织，以及 已建立的类胰蛋白酶对支气管活性多肽的破坏作用 组胺在体外对支气管收缩的增强作用。一个子集 呼吸道肥大细胞中含有第二种主要的丝氨酸蛋白酶--凝乳酶。 进一步的研究解决了狗和人凝乳酶的一级结构， 将人类基因定位于一簇造血丝氨酸蛋白酶 基因，并建立了人与狗的密切关系 增加组胺诱导的体内血管渗漏的酶 在体外刺激腺体细胞分泌。在人的呼吸道中，凝乳酶- 发现含有肥大细胞的细胞在 粘膜下腺。尽管取得了这些进展，也有其他团体在 这些酶的性质及其在植物生长中的作用 人们对航空公司的理解并不完全。现在提议的研究将使用 生化、形态和生理学方法进一步 探索这些肥大细胞和相关肥大细胞的属性和作用 呼吸道炎症中的蛋白酶。调查的一个途径是 一种新发现的近亲的特征和功能的探讨 指类胰蛋白酶；被称为dMCP-3，它的存在是从一个 从犬肥大细胞瘤细胞中克隆出‘孤儿’基因。这个结构， DMCP-3的分泌、催化特性及呼吸道组织表达 并将对其假定的人类同源物进行检查。更多的研究将 肥大细胞蛋白水解酶在呼吸道组织生长中的作用 和重建，特别关注类胰酶作为生长因子 气道腺和平滑肌，并将使用一种表达克隆 识别和克隆一个可能的受体的策略 类胰蛋白酶的有丝分裂作用。肥大细胞也将作为一种 有别于丝氨酸的基质降解锌金属蛋白酶的来源 类胰蛋白酶、乳糜酶和dMCP-3等蛋白酶。最后，提出了 研究将探索类胰蛋白酶对血管通透性的调节 和凝乳酶及其与凝血酶的相互作用。这些研究可能 揭示肥大细胞分泌性蛋白水解酶的意外作用 为开发新的治疗方法提供了基础 呼吸道炎症的管理。

The major stored and secreted proteins of mast cells are proteases. The most abundant of these in tryptase, a trypsin-like serine protease that is synthesized by virtually all lung and airway mast cells and resists inactivation by circulating antiproteases following release. Recent work deciphered the primary structure of dog and human tryptases, discovered the novel intron-exon organization of human tryptase genes, and established tryptase's destruction of bronchoactive peptides and potentiation of histamine-induced bronchoconstriction in vitro. A subset of airway mast cells contain a second major serine protease, chymase. Further studies solved the primary structure of dog and human chymase, localized the human gene to a cluster of hematopoietic serine protease genes, and established the close relationship of the human to the dog enzyme, which increase histamine-induced vascular leak in vivo an stimulates gland cell secretion in vitro. In human airway, chymase- containing mast cells were found to be particularly abundant near submucosal glands. Despite these advances and those of other groups in the field, the characteristics of these enzymes and their function in the airways are incompletely understood. The studies now proposed will use biochemical, morphological and physiological approaches to further explore the properties and roles of these and relative mast cell proteases in airway inflammation. One avenue of investigation is an exploration of the features and functions of a newly discovered relative of tryptase; known as dMCP-3, whose existence is predicted from an 'orphan' cDNA cloned from dog mastocytoma cells. The structure, secretion, catalytic properties and airway tissue expression of dMCP-3 and its putative human homolog will be examined. Additional studies will examine the participation of mast cell proteases in airway tissue growth and remodeling, focusing particularly on tryptases as growth factors for airway glands and smooth muscle, and will use an expression cloning strategy to identify and clone a putative receptor mediating the mitogenic effects of tryptase. Mast cells also will be examined as a source of matrix-degrading Zn++-metalloproteases distinct from serine proteases such as tryptase, chymase, and dMCP-3. Finally, the proposed studies will explore the modulation of vascular permeability by tryptase and chymase and their interactions with thrombin. These studies may reveal unsuspected roles for mast cell secretory proteases and may suggest a basis for developing new therapeutic approaches to the management of airway inflammation.