Elastase and cathepsin G of human monocytes. Quantification of cellular content, release in response to stimuli, and heterogeneity in elastase-mediated proteolytic activity.
Elastase and cathepsin G of human monocytes. Quantification of cellular content, release in response to stimuli, and heterogeneity in elastase-mediated proteolytic activity.
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DOI：
10.4049/jimmunol.143.9.2961
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发表时间：
1989-11
影响因子：
4.4
通讯作者：
E. J. Campbell;E. K. Silverman;M. Campbell
中科院分区：
文献类型：
--
作者：
E. J. Campbell;E. K. Silverman;M. Campbell
人外周血单核细胞含有人白细胞弹性蛋白酶（HLE）和组织蛋白酶G（CG），丝氨酸蛋白酶最初描述于多形核中性粒细胞（PMN）的嗜天青颗粒中。在本研究中，对新鲜收获的单核细胞的免疫反应性HLE和CG进行了定量;为了开始阐明这些酶在细胞外事件中的潜在作用，测量了响应刺激的释放，沿着单核细胞对表面结合蛋白的蛋白水解活性。我们的研究结果表明，单核细胞的全细胞提取物含有约6%的量的HLE，因为相当数量的PMN提取物。在PMA的体外反应中，单核细胞在60分钟内释放了39%至53%的HLE和CG，分数释放大于PMN。此外，当佛波醇刺激的单核细胞粘附到纤连蛋白包被的表面时，观察到广泛的HLE介导的表面结合蛋白的蛋白水解。在蛋白酶抑制剂的存在下，这些细胞的蛋白水解是相当感兴趣的，因为一个亚群（占总数的15 - 20%）表达了明显的但局部的蛋白水解活性，可能通过接触介导的机制逃避抑制。这些数据表明，新鲜收获的单核细胞的亚群富含HLE和CG（丝氨酸蛋白酶传统上与PMN），可以迅速释放HLE和CG响应刺激，并可以利用HLE的细胞外蛋白水解。单核细胞衍生的丝氨酸蛋白酶可能参与以前与PMN衍生的HLE和CG相关的细胞外事件。
Human peripheral blood monocytes contain human leukocyte elastase (HLE) and cathepsin G (CG), serine proteinases originally described in azurophil granules of polymorphonuclear neutrophils (PMN). Immunoreactive HLE and CG of freshly harvested monocytes have been quantified in this study; to begin to elucidate potential roles for these enzymes in extracellular events, release in response to stimuli has been measured, along with proteolytic activity of monocytes toward surface-bound proteins. Our results indicate that whole-cell extracts of monocytes contain approximately 6% of the amount of HLE as do extracts of comparable numbers of PMN. In response to PMA in vitro, monocytes released 39 to 53% of their content of HLE and CG within 60 min, a fractional release greater than that of PMN. Furthermore, when phorbol-stimulated monocytes were adherent to a fibronectin-coated surface, extensive HLE-mediated proteolysis of the surface-bound protein was observed. Proteolysis by such cells in the presence of proteinase inhibitors was of considerable interest, since a subpopulation (15 to 20% of the total) expressed marked but localized proteolytic activity, possibly escaping inhibition through contact-mediated mechanisms. These data indicate that a subpopulation of freshly harvested monocytes is rich in HLE and CG (serine proteinases traditionally associated with PMN), can promptly release HLE and CG in response to stimuli, and can utilize HLE for extracellular proteolysis. Monocyte-derived serine proteinases may participate in extracellular events formerly associated with PMN-derived HLE and CG.