Netzel-Arnett Sarah, Mitola David J, Yamada Susan S, Chrysovergis Kali, Holmbeck Kenn, Birkedal-Hansen Henning, Bugge Thomas H
Matrix Metalloproteinase Unit, NIDCR, National Institutes of Health, Bethesda, Maryland 20892, USA.
J Biol Chem. 2002 Nov 22;277(47):45154-61. doi: 10.1074/jbc.M206354200. Epub 2002 Aug 20.
Matrix metalloproteinase-14 is required for degradation of fibrillar collagen by mesenchymal cells. Here we show that keratinocytes use an alternative plasminogen and matrix metalloproteinase-13-dependent pathway for dissolution of collagen fibrils. Primary keratinocytes displayed an absolute requirement for serum to dissolve collagen. Dissolution of collagen was abolished in plasminogen-depleted serum and could be restored by the exogenous addition of plasminogen. Both plasminogen activator inhibitor-1 and tissue inhibitor of metalloproteinase blocked collagen dissolution, demonstrating the requirement of both plasminogen activation and matrix metalloproteinase activity for degradation. Cell surface plasmin activity was critical for the degradation process as aprotinin, but not alpha(2)-antiplasmin, prevented collagen dissolution. Keratinocytes with single deficiencies in either urokinase or tissue plasminogen activator retained the ability to dissolve collagen. However, collagen fibril dissolution was abolished in keratinocytes with a combined deficiency in both urokinase and tissue plasminogen activator. Combined, but not single, urokinase and tissue plasminogen activator deficiency also completely blocked the activation of the fibrillar collagenase, matrix metalloproteinase-13, by keratinocytes. The activation of matrix metalloproteinase-13 in normal keratinocytes was prevented by plasminogen activator inhibitor-1 and aprotinin but not by tissue inhibitor of metalloproteinase-1 and -2, suggesting that plasmin activates matrix metalloproteinase-13 directly. We propose that plasminogen activation facilitates keratinocyte-mediated collagen breakdown via the direct activation of matrix metalloproteinase-13 and possibly other fibrillar collagenases.
间充质细胞降解纤维状胶原蛋白需要基质金属蛋白酶-14。在此我们表明，角质形成细胞利用一种替代的纤溶酶原和基质金属蛋白酶-13依赖性途径来溶解胶原纤维。原代角质形成细胞对血清溶解胶原蛋白表现出绝对需求。在缺乏纤溶酶原的血清中，胶原蛋白的溶解被消除，而通过外源添加纤溶酶原可恢复溶解。纤溶酶原激活物抑制剂-1和金属蛋白酶组织抑制剂均能阻断胶原蛋白的溶解，这表明纤溶酶原激活和基质金属蛋白酶活性对于降解都是必需的。细胞表面纤溶酶活性对降解过程至关重要，因为抑肽酶可阻止胶原蛋白溶解，而α2-抗纤溶酶则不能。尿激酶或组织纤溶酶原激活物单一缺陷的角质形成细胞仍保留溶解胶原蛋白的能力。然而，尿激酶和组织纤溶酶原激活物联合缺陷的角质形成细胞中，胶原纤维的溶解被消除。尿激酶和组织纤溶酶原激活物联合缺陷（而非单一缺陷）也完全阻断了角质形成细胞对纤维状胶原酶基质金属蛋白酶-13的激活。纤溶酶原激活物抑制剂-1和抑肽酶可阻止正常角质形成细胞中基质金属蛋白酶-13的激活，但金属蛋白酶组织抑制剂-1和-2则不能，这表明纤溶酶直接激活基质金属蛋白酶-13。我们提出，纤溶酶原激活通过直接激活基质金属蛋白酶-13以及可能的其他纤维状胶原酶，促进角质形成细胞介导的胶原蛋白分解。
