Foda H D, George S, Rollo E, Drews M, Conner C, Cao J, Panettieri R A, Zucker S
Department of Medicine and Research, Veterans Affairs Medical Center, Northport, New York 11768, USA.
Am J Physiol. 1999 Jul;277(1):L174-82. doi: 10.1152/ajplung.1999.277.1.L174.
Matrix metalloproteinases (MMPs) play an important role in tumor metastasis and invasion, inflammatory tissue destruction and remodeling, wound healing, and angiogenesis. The 72-kDa gelatinase A is the most widely distributed of all the MMPs, and along with the 92-kDa gelatinase B, both play an important role in the turnover of basement membrane. The role of MMPs in chronic airway inflammation and remodeling has received scant attention. In this study, we sought to examine the release and activation of gelatinases from human airway smooth muscle (ASM) cells and the effect of tumor necrosis factor-alpha and phorbol 12-myristate 13-acetate (PMA) on this release and activation. The role of membrane type 1 MMP (MT1-MMP) and tissue inhibitor of MMP (TIMP)-2 in activating progelatinase A has been explored. We have demonstrated, using human airway smooth muscle cells in culture, that 1) ASM releases gelatinase A constitutively and when stimulated with PMA and tumor necrosis factor-alpha releases gelatinase B, and the release of gelatinase B is protein kinase C dependent because it is blocked by H-7 and staurosporin; 2) treatment of ASM cells with PMA or concanavalin A failed to activate progelatinase A despite these agents increasing cell expression of MT1-MMP; and 3) the inability of ASM cell membranes to activate progelatinase A is most likely secondary to the high levels of TIMP-2 on the cell membrane. In conclusion, our results demonstrate that human ASM cells constitutively secrete progelatinase A and when stimulated with proinflammatory mediators secrete gelatinase B. The released gelatinases A and B may be important factors in the airway remodeling that occurs in asthma.
基质金属蛋白酶（MMPs）在肿瘤转移与侵袭、炎症性组织破坏与重塑、伤口愈合及血管生成中发挥着重要作用。72 kDa的明胶酶A是所有MMPs中分布最广泛的，与92 kDa的明胶酶B一起，在基底膜的更新中均发挥重要作用。MMPs在慢性气道炎症和重塑中的作用鲜有研究关注。在本研究中，我们试图检测人气道平滑肌（ASM）细胞中明胶酶的释放与激活情况，以及肿瘤坏死因子-α和佛波酯12-肉豆蔻酸酯13-乙酸酯（PMA）对这种释放与激活的影响。我们还探讨了膜型1基质金属蛋白酶（MT1-MMP）和基质金属蛋白酶组织抑制剂（TIMP）-2在激活前明胶酶A中的作用。我们利用培养的人气道平滑肌细胞证明：1）ASM组成性释放明胶酶A，在用PMA和肿瘤坏死因子-α刺激时释放明胶酶B，且明胶酶B的释放依赖蛋白激酶C，因为它可被H-7和星形孢菌素阻断；2）用PMA或伴刀豆球蛋白A处理ASM细胞未能激活前明胶酶A，尽管这些试剂可增加MT1-MMP的细胞表达；3）ASM细胞膜无法激活前明胶酶A很可能是由于细胞膜上TIMP-2水平较高。总之，我们的结果表明，人ASM细胞组成性分泌前明胶酶A，在受到促炎介质刺激时分泌明胶酶B。释放的明胶酶A和B可能是哮喘中发生的气道重塑的重要因素。
