CELL-SURFACE PROTEINASES IN PULMONARY INFLAMMATION

炎症过程中肺细胞外基质的蛋白质水解 肺气肿和其他致残性疾病发病机制中的关键事件 肺部疾病 我们有几条初步证据 表明人白细胞弹性蛋白酶（HLE）催化活性， 组织蛋白酶G（CG）集中在人多形性腺瘤细胞表面 嗜中性粒细胞，即使在富含嗜中性粒细胞的环境中，如存在于 细胞外空间。 我们的假设是活跃的细胞- 炎症细胞上的表面结合蛋白酶 通过特定的粘附分子与潜在的基质基质结合， 允许细胞穿透组织屏障， 潜在的基质损伤。 此外，最近的证据表明， 中性粒细胞的另一种丝氨酸蛋白酶（蛋白酶3; PR 3）是抗原 被一类“抗中性粒细胞胞质抗体”（ANCA）识别 在韦格纳肉芽肿病患者中。 我们的假设是 当PR 3在中性粒细胞的细胞表面表达时， 单核吞噬细胞，它成为自身免疫的主要目标， 过程 随后的细胞活动，然后都激活和吸引 炎症细胞，导致恶性循环， 坏死性血管炎 我们将致力于实现以下具体目标。1)丝氨酸的研究 蛋白酶（HLE，CG和PR 3）结合到人的细胞表面 中性粒细胞和单核细胞，关于： 刺激的细胞; B）催化活性和抑制抗性; c） 与细胞表面结合的机制;和d）炎性细胞 通过自身抗体激活。2)封闭区蛋白质水解的研究 细胞和下基板之间的接触，关于：a）共- 细胞表面结合丝氨酸蛋白酶的分布和选择 极化细胞上的粘附分子;和B）粘附的重要性 补丁在允许耐药蛋白水解。 炎症细胞既降解生物学上重要的基质， 蛋白质在体内，也提供了很好的模型，研究 体外耐药基质蛋白水解。 我们预计 对细胞表面丝氨酸蛋白酶活性的拟议研究将 提供了对细胞外严格控制的机制的见解， 蛋白水解活性发生在细胞表面，以及进入 炎症过程中组织损伤的潜在基本机制。

Proteolysis of lung extracellular matrix during inflammation is a pivotal event in pathogenesis of pulmonary emphysema and other disabling lung diseases. We have several lines of preliminary evidence which indicate that catalytic activity of human leukocyte elastase (HLE) and cathepsin G (CG) is focused at the cell surface of human polymorphonuclear neutrophils, even in an inhibitor-rich environment such as exists in the extracellular space in vivo. Our working hypothesis is that active cell- surface-bound proteinases on inflammatory cells are brought into contact with potential matrix substrates by specific adherence molecules, permitting the cells to penetrate tissue barriers and creating the potential for matrix injury. Moreover, recent evidence indicates that another serine proteinase of neutrophils (proteinase 3; PR3) is the antigen recognized by one class of "anti-neutrophil cytoplasmic antibodies" (ANCA) in individuals with Wegener's granulomatosis. Our working hypothesis is that when PR3 is expressed on the cell surface of neutrophils and mononuclear phagocytes, it becomes the primary target of the autoimmune process. Ensuing cellular events then both activate and attract inflammatory cells, leading to a vicious cycle which culminates in necrotizing vasculitis. We will address the following Specific Aims. 1) Study of serine proteinases (HLE, CG, and PR3) bound to the cell surface of human neutrophils and monocytes, with regard to: a) quantification on resting and stimulated cells; b) catalytic activity and resistance to inhibition; c) mechanism(s) of binding to the cell surface; and d) inflammatory cell activation by autoantibodies. 2) Study of proteolysis in zones of close contact between cells and subjacent substrates, with regard to: a) co- distribution of cell-surface-bound serine proteinases and selected adherence molecules on polarized cells; and b) importance of adhesion patches in permitting inhibitor-resistant proteolysis. Inflammatory cells both degrade biologically important matrix proteins in vivo and also provide excellent models for study of inhibitor-resistant matrix proteolysis in vitro. We anticipate that the proposed studies of serine proteinase activity at the cell surface will provide insights into mechanisms of tightly controlled extracellular proteolytic activity occurring at the cell surface, as well as into potential basic mechanisms of tissue injury during inflammation.