Akers I A, Parsons M, Hill M R, Hollenberg M D, Sanjar S, Laurent G J, McAnulty R J
Centre for Cardiopulmonary Biochemistry and Respiratory Medicine, The Royal Free and University College Medical School, The Rayne Institute, London WC1E 6JJ, United Kingdom.
Am J Physiol Lung Cell Mol Physiol. 2000 Jan;278(1):L193-201. doi: 10.1152/ajplung.2000.278.1.L193.
Mast cells play a potentially important role in fibroproliferative diseases, releasing mediators including tryptase that are capable of stimulating fibroblast proliferation and procollagen synthesis. The mechanism by which tryptase stimulates fibroblast proliferation is unclear, although recent studies suggest it can activate protease-activated receptor (PAR)-2. We therefore investigated the role of PAR-2 in tryptase-induced proliferation of human fetal lung and adult lung parenchymal and airway fibroblasts and, for comparative purposes, adult dermal fibroblasts. Tryptase (0.7-70 mU/ml) induced concentration-dependent increases in proliferation of all fibroblasts studied. Antipain, bis(5-amidino-2-benzimidazolyl)methane, and benzamidine inhibited tryptase-induced fibroblast proliferation, demonstrating that proteolytic activity is required for the proliferative effects of tryptase. RT-PCR demonstrated the presence of PAR-2 mRNA, and immunohistochemical staining localized PAR-2 to the cell surface of lung fibroblasts. In addition, specific PAR-2 activating peptides, SLIGKV and SLIGRL, mimicked the proliferative effects of tryptase. In contrast, human dermal fibroblasts only weakly stained with the PAR-2 antibody, PAR-2 mRNA was almost undetectable, and fibroblasts did not respond to PAR-2 activating peptides. These results suggest that tryptase induces lung, but not dermal, fibroblast proliferation via activation of PAR-2 and are consistent with the hypothesis that the release of tryptase from activated mast cells may play an important role in the fibroproliferative response observed in asthma, chronic obstructive pulmonary disease, and patients with pulmonary fibrosis.
肥大细胞在纤维增生性疾病中可能发挥重要作用，释放包括类胰蛋白酶在内的介质，这些介质能够刺激成纤维细胞增殖和前胶原合成。尽管最近的研究表明类胰蛋白酶可激活蛋白酶激活受体（PAR）-2，但类胰蛋白酶刺激成纤维细胞增殖的机制尚不清楚。因此，我们研究了PAR-2在类胰蛋白酶诱导的人胎儿肺、成人肺实质和气道成纤维细胞增殖中的作用，并且为了进行比较，还研究了成人真皮成纤维细胞。类胰蛋白酶（0.7 - 70 mU/ml）可诱导所有研究的成纤维细胞增殖呈浓度依赖性增加。抗蛋白酶、双（5-脒基-2-苯并咪唑基）甲烷和苯甲脒可抑制类胰蛋白酶诱导的成纤维细胞增殖，表明类胰蛋白酶的增殖作用需要蛋白水解活性。逆转录-聚合酶链反应（RT-PCR）显示存在PAR-2信使核糖核酸（mRNA），免疫组织化学染色将PAR-2定位于肺成纤维细胞的细胞表面。此外，特异性PAR-2激活肽SLIGKV和SLIGRL模拟了类胰蛋白酶的增殖作用。相比之下，人真皮成纤维细胞仅被PAR-2抗体弱阳性染色，PAR-2 mRNA几乎检测不到，并且成纤维细胞对PAR-2激活肽无反应。这些结果表明，类胰蛋白酶通过激活PAR-2诱导肺成纤维细胞而非真皮成纤维细胞增殖，这与以下假设一致：活化的肥大细胞释放类胰蛋白酶可能在哮喘、慢性阻塞性肺疾病和肺纤维化患者中观察到的纤维增生反应中起重要作用。
