Colige A C, Lambert C A, Nusgens B V, Lapière C M
Laboratory of Experimental Dermatology, University of Liège, CHU Sart-Tilman, Sart-Tilman, Liège, Belgium.
Biochem J. 1992 Jul 1;285 ( Pt 1)(Pt 1):215-21. doi: 10.1042/bj2850215.
Investigations of the effect of epidermal growth factor (EGF) on the expression of four genes involved in the turnover of the extracellular matrix, collagen type I, collagenase, stromelysin and tissue inhibitor of metalloproteinases (TIMP) were performed on four strains of skin fibroblasts in vitro. Addition of EGF to subconfluent cultures for increasing periods of time up to 5 days induced an inhibition of procollagen alpha 1(I) mRNA and a strong stimulation of collagenase (100-fold) and stromelysin (1000-fold) mRNAs, whereas the mRNA of TIMP was increased to a lesser extent (5-fold). After a 40 h pulse with EGF, these effects persisted for 24-48 h after withdrawal of the growth factor and slowly diminished thereafter to attain control values after several days. By culturing fibroblasts for increasing periods of time, different levels of confluence were obtained allowing for the deposition of an extracellular biomatrix. The steady-state level of collagenase and stromelysin mRNAs were profoundly depressed in confluent as against non-confluent cultures, whereas no major change for TIMP and procollagen alpha 1(I) mRNAs was observed. Upon treatment of these cultures with EGF for 48h, the steady-state level of collagenase, stromelysin and TIMP increased, whereas procollagen alpha 1(I) mRNA was slightly reduced. These modifications were, at least in part, dependent upon a regulation of the transcription rate, as suggested from run-off experiments. Similar states of confluence were obtained by seeding cells at increasing densities in short-term cultures in which cell-cell contact predominated. In such culture conditions, the collagenase and stromelysin mRNAs were enhanced in high as compared to low density cultures. The response to EGF was progressively decreased for collagenase, stromelysin and, to a lesser extent, TIMP mRNAs at most densities and a complete lack of response to EGF at the highest cell density was observed. Under all culture conditions the modulation of collagenase mRNA was paralleled by similar modifications of enzyme activity. These results emphasize the importance of the cell-cell contacts and cell-matrix interactions in the expression of the genes coding for metalloproteinases or their inhibitor and their modulation by growth factors.
在体外对四株皮肤成纤维细胞进行了研究，以探讨表皮生长因子（EGF）对参与细胞外基质周转的四种基因，即I型胶原、胶原酶、基质溶解素和金属蛋白酶组织抑制剂（TIMP）表达的影响。向亚汇合培养物中添加EGF，持续时间长达5天，结果导致前胶原α1（I）mRNA受到抑制，胶原酶（100倍）和基质溶解素（1000倍）mRNA受到强烈刺激，而TIMP的mRNA增加幅度较小（5倍）。用EGF脉冲处理40小时后，这些效应在生长因子撤除后持续24 - 48小时，此后逐渐减弱，数天后达到对照值。通过将成纤维细胞培养更长时间，可获得不同程度的汇合状态，从而允许细胞外生物基质的沉积。与未汇合培养物相比，汇合培养物中胶原酶和基质溶解素mRNA的稳态水平显著降低，而TIMP和前胶原α1（I）mRNA未观察到重大变化。用EGF处理这些培养物48小时后，胶原酶、基质溶解素和TIMP的稳态水平升高，而前胶原α1（I）mRNA略有降低。这些修饰至少部分依赖于转录速率的调节，这从连续转录实验中可以看出。通过在短期培养中以增加的密度接种细胞（其中细胞 - 细胞接触占主导）可获得类似的汇合状态。在这种培养条件下，与低密度培养相比，高密度培养中胶原酶和基质溶解素mRNA增强。在大多数密度下，胶原酶、基质溶解素以及在较小程度上TIMP的mRNA对EGF的反应逐渐降低，在最高细胞密度下观察到对EGF完全无反应。在所有培养条件下，胶原酶mRNA 的调节与酶活性的类似修饰平行。这些结果强调了细胞 - 细胞接触和细胞 - 基质相互作用在编码金属蛋白酶或其抑制剂的基因表达及其受生长因子调节中的重要性。
