Creemers L B, Jansen I D, Docherty A J, Reynolds J J, Beertsen W, Everts V
Department of Periodontology, Academic Center of Denistry, Amsterdam, The Netherlands.
Matrix Biol. 1998 Apr;17(1):35-46. doi: 10.1016/s0945-053x(98)90123-8.
The degradation of soft connective tissue collagen is considered to depend on the activity of various proteolytic enzymes, particularly those belonging to the group of matrix metalloproteinases and cysteine proteinases. In the present study, we investigated the contribution of these enzymes to this process. Using a general inhibitor of MMPs (SC44463), collagen degradation was strongly inhibited, by about 40% after 24 h and up to 80% after 72 h of culturing. Blockage of cysteine proteinase activity (with leupeptin or E-64) reduced breakdown at these time intervals by 50% and 20%, respectively. Given the abundant presence of gelatinases--in particular gelatinase A (MMP-2)--in the tissue, the effect of an inhibitor selective for gelatinases (CT1166) was studied. Gelatinase inhibition resulted in a dose-dependent decrease of collagen breakdown up to 90% after 48 h. The ability of gelatinase A to degrade collagens was demonstrated by the induction of breakdown in devitalized explants by addition of activated gelatinase A, or by activation of endogenous enzyme with 4-aminophenylmercuric acetate. This latter effect was not found with plasmin, an activator of MMPs other than gelatinase A. Finally, the relevance of gelatinase A to the in vivo degradation of soft connective tissue collagen was implicated by the significant correlation found between its activity and the collagen turnover rates of four soft connective tissues (tooth pulp, periodontal ligament, molar gingiva and skin). We conclude that collagen degradation in soft connective tissue is mediated by MMPs and to a lesser extent by cysteine proteinases. Our data are the first to attach a key role to gelatinase A in this process.
软结缔组织胶原蛋白的降解被认为取决于多种蛋白水解酶的活性，特别是那些属于基质金属蛋白酶和半胱氨酸蛋白酶组的酶。在本研究中，我们研究了这些酶在这一过程中的作用。使用基质金属蛋白酶的一种通用抑制剂（SC44463），胶原蛋白降解受到强烈抑制，培养24小时后约40%，培养72小时后高达80%。半胱氨酸蛋白酶活性的阻断（用亮抑酶肽或E-64）在这些时间间隔分别使分解减少50%和20%。鉴于组织中明胶酶（特别是明胶酶A，即基质金属蛋白酶-2）的大量存在，研究了一种对明胶酶有选择性的抑制剂（CT1166）的作用。明胶酶抑制导致胶原蛋白分解在48小时后呈剂量依赖性下降，最高可达90%。通过添加活化的明胶酶A诱导失活外植体中的分解，或用对乙酰氨基苯汞激活内源性酶，证明了明胶酶A降解胶原蛋白的能力。纤溶酶（明胶酶A以外的基质金属蛋白酶激活剂）未发现后一种作用。最后，通过其活性与四种软结缔组织（牙髓、牙周韧带、磨牙牙龈和皮肤）的胶原蛋白周转率之间的显著相关性，表明明胶酶A与软结缔组织胶原蛋白的体内降解相关。我们得出结论，软结缔组织中的胶原蛋白降解由基质金属蛋白酶介导，半胱氨酸蛋白酶的作用较小。我们的数据首次表明明胶酶A在这一过程中起关键作用。
