Rossman M D, Maida B T, Douglas S D
Department of Pediatrics, University of Pennsylvania School of Medicine, Philadelphia.
Cell Immunol. 1990 Apr 1;126(2):268-77. doi: 10.1016/0008-8749(90)90320-q.
Alveolar macrophages are thought to play an important role in ongoing tissue breakdown and repair processes in the normal lung. The secretion and regulation of cathepsin D (important for the final breakdown of collagen) and fibronectin (involved in the healing process) in human peripheral blood monocytes (PBM) and pulmonary alveolar macrophages (PAM) were investigated. Cathepsin D enzyme activity was measured by quantitating the TCA-soluble fragments of [3H]hemoglobin. Freshly isolated PBM contained less cell-associated cathepsin D activity than did freshly isolated PAM (314 +/- 35 micrograms/10(6) cells vs 381 +/- 35 micrograms/10(6) cells, respectively). After 7-10 days in culture, cell-associated enzyme levels in both PBM and PAM were significantly increased (P less than 0.001 for PBM; P less than 0.0001 for PAM). In addition, freshly isolated PAM secreted more cathepsin D than did freshly isolated PBM (5.8 +/- 3.2 micrograms/10(6) cells vs 0.83 +/- 0.83 micrograms/10(6) cells, P less than 0.02). In the presence of LPS (10 micrograms/ml), cell-associated cathepsin D was inhibited in both PBM and PAM. With the addition of gamma-IFN (500 U/ml), both cell-associated and secreted enzyme were increased in freshly isolated and 10-day-cultured PBM and PAM. In parallel studies, fibronectin secretion (by ELISA assay) in both PBM and PAM increased over time in culture. LPS had no effect on PBM or PAM secretion of human fibronectin while gamma-IFN increased PBM and PAM fibronectin levels. Thus, both macrophage cathepsin D activity and fibronectin secretion are increased by gamma-interferon while macrophage cathepsin D activity, but not fibronectin secretion, is decreased by LPS. These studies demonstrate that human macrophage cathepsin D activity is actively modulated by inflammatory mediators and that macrophage mediators of tissue breakdown and repair are not modulated synchronously.
肺泡巨噬细胞被认为在正常肺组织的持续分解和修复过程中发挥重要作用。研究了人外周血单核细胞（PBM）和肺泡巨噬细胞（PAM）中组织蛋白酶D（对胶原蛋白的最终分解很重要）和纤连蛋白（参与愈合过程）的分泌及调节。通过定量[3H]血红蛋白的三氯乙酸可溶性片段来测定组织蛋白酶D的酶活性。新鲜分离的PBM所含的细胞相关组织蛋白酶D活性低于新鲜分离的PAM（分别为314±35微克/10^6细胞和381±35微克/10^6细胞）。培养7 - 10天后，PBM和PAM中的细胞相关酶水平均显著升高（PBM中P＜0.001；PAM中P＜0.0001）。此外，新鲜分离的PAM分泌的组织蛋白酶D比新鲜分离的PBM多（5.8±3.2微克/10^6细胞对0.83±0.83微克/10^6细胞，P＜0.02）。在脂多糖（LPS，10微克/毫升）存在的情况下，PBM和PAM中的细胞相关组织蛋白酶D均受到抑制。加入γ-干扰素（500单位/毫升）后，新鲜分离的以及培养10天的PBM和PAM中细胞相关和分泌的酶均增加。在平行研究中，培养过程中PBM和PAM中纤连蛋白的分泌（通过ELISA测定）随时间增加。LPS对人纤连蛋白的PBM或PAM分泌没有影响，而γ-干扰素增加了PBM和PAM中的纤连蛋白水平。因此，γ-干扰素可增加巨噬细胞组织蛋白酶D活性和纤连蛋白分泌，而LPS可降低巨噬细胞组织蛋白酶D活性，但不影响纤连蛋白分泌。这些研究表明，人巨噬细胞组织蛋白酶D活性受到炎症介质的积极调节，并且组织分解和修复的巨噬细胞介质并非同步调节。
