ROLE OF MAST CELL PROTEASES IN AIRWAY INFLAMMATION

肥大细胞主要储存和分泌的蛋白质是蛋白酶。 的 其中最丰富的是类胰蛋白酶，一种胰蛋白酶样丝氨酸蛋白酶， 由几乎所有的肺和气道肥大细胞合成， 释放后通过循环抗蛋白酶灭活。 最近的工作 破译了狗和人类胰蛋白酶的初级结构， 人类类胰蛋白酶基因的新型内含子-外显子结构，以及 建立类胰蛋白酶对支气管活性肽的破坏， 组胺诱导的支气管收缩在体外的增强。 一个子集 含有第二种主要的丝氨酸蛋白酶，糜酶。 进一步的研究解决了狗和人类糜酶的一级结构， 将人类基因定位于一组造血丝氨酸蛋白酶 基因，并建立了人类与狗的密切关系 这种酶在体内增加组胺诱导的血管渗漏， 刺激体外腺细胞分泌。 在人体气道中，糜酶- 发现含有肥大细胞的细胞在 粘膜下腺体 尽管这些进步和其他群体的进步， 本文综述了这些酶的研究领域、特性及其在生物合成中的作用， 对气道的了解还不完全。 现在提出的研究将使用 生物化学、形态学和生理学方法， 探讨这些及相关肥大细胞的性质和作用 蛋白酶在气道炎症中的作用调查的一个途径是 探索新发现的亲戚的特征和功能 类胰蛋白酶;被称为dMCP-3，其存在是从一个 从狗肥大细胞瘤细胞克隆的“孤儿”cDNA。 结构， dMCP-3的分泌、催化特性和气道组织表达 和它的假定人类同源物将被检验。 其他研究将 检查肥大细胞蛋白酶在气道组织生长中的参与 和重塑，特别关注胰蛋白酶作为生长因子， 气道腺体和平滑肌，并将使用表达克隆 策略，以确定和克隆一个假定的受体介导的 类胰蛋白酶的促有丝分裂作用。 肥大细胞也将作为一种 不同于丝氨酸基质降解Zn++-金属蛋白酶的来源 蛋白酶如类胰蛋白酶、糜蛋白酶和dMCP-3。 最后，建议 研究将探索类胰蛋白酶对血管通透性的调节 和糜酶以及它们与凝血酶的相互作用。 这些研究可能 揭示了肥大细胞分泌蛋白酶的未知作用， 为开发新的治疗方法提供了基础。 管理气道炎症。

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.