Fini M E, Girard M T
Eye Research Institute, Harvard Medical School, Boston, Massachusetts 02114.
J Cell Sci. 1990 Oct;97 ( Pt 2):373-83. doi: 10.1242/jcs.97.2.373.
We have examined the pattern of expression of four different matrix metalloproteinases (MMPs), collagenase, stromelysin, 92 kD gelatinase, and 72 kD gelatinase, by primary and passaged cultures of rabbit corneal fibroblasts. Primary cultures of this cell type have previously been shown to reproduce the normal tissue regulation of collagenase expression. We demonstrate qualitative and quantitative changes in the pattern of MMP expression as the cells are passaged in culture. Only a single MMP, 72 kD gelatinase, is constitutively expressed by primary fibroblast cultures. Phorbol myristate acetate (PMA) treatment upregulates expression of 72 kD gelatinase and turns on the expression of collagenase and stromelysin, as well as 92 kD gelatinase. However, the degree to which MMP expression is induced is minimal. Cells subcultured but a single time constitutively produce not only 72 kD gelatinase, but also collagenase and stromelysin. In addition, PMA treatment upregulates expression of collagenase, stromelysin and 92 kD gelatinase to high levels. In contrast, the expression of 72 kD gelatinase is repressed by treatment of passaged cell cultures with PMA. Our data indicate that the cell does not simply turn the MMP genes on or off, as a group, in response to various agents, but that it has the capacity for fine control over which MMPs are expressed and the degree to which each is expressed. Changes in MMP protein expression induced by PMA treatment are correlated with changes in specific mRNA levels in passaged cultures. The kinetics of mRNA accumulation suggest that the MMP genes can respond to multiple intracellular signals initiated in a temporal cascade by PMA. It is the combined effects of the individual signals on the accumulation of specific mRNAs that must determine the ultimate pattern of MMP protein expression. The distinct patterns of MMP expression produced by primary and passaged cell cultures may be analogous to patterns of expression that might occur under particular in vivo conditions.
我们已经通过兔角膜成纤维细胞的原代培养和传代培养，研究了四种不同基质金属蛋白酶（MMPs），即胶原酶、基质溶解素、92kD明胶酶和72kD明胶酶的表达模式。此前已表明，这种细胞类型的原代培养能够重现胶原酶表达的正常组织调控。我们证明，随着细胞在培养中传代，MMP表达模式会发生定性和定量的变化。原代成纤维细胞培养物仅组成性表达单一的MMP，即72kD明胶酶。佛波醇肉豆蔻酸酯乙酸盐（PMA）处理可上调72kD明胶酶的表达，并开启胶原酶、基质溶解素以及92kD明胶酶的表达。然而，MMP表达的诱导程度极小。仅传代培养一次的细胞不仅组成性产生72kD明胶酶，还产生胶原酶和基质溶解素。此外，PMA处理可将胶原酶、基质溶解素和92kD明胶酶的表达上调至高水平。相比之下，用PMA处理传代细胞培养物会抑制72kD明胶酶的表达。我们的数据表明，细胞并非简单地根据各种因子整体开启或关闭MMP基因，而是有能力对表达哪些MMP以及每种MMP的表达程度进行精细调控。PMA处理诱导的MMP蛋白表达变化与传代培养中特定mRNA水平的变化相关。mRNA积累的动力学表明，MMP基因可对PMA在时间级联中引发的多个细胞内信号作出反应。正是各个信号对特定mRNA积累的综合作用必定决定了MMP蛋白表达的最终模式。原代和传代细胞培养物产生的不同MMP表达模式可能类似于在特定体内条件下可能出现的表达模式。
