Wojta J, Nakamura T, Fabry A, Hufnagl P, Beckmann R, McGrath K, Binder B R
Department of Medical Physiology, University of Vienna, Austria.
Blood. 1994 Jul 1;84(1):151-7.
HGF is a powerful mitogen for both rat and human hepatocytes, epithelial cells and endothelial cells in vitro, and is angiogenic in vivo. It has considerable homology with plasminogen and has been shown to upregulate urokinase-type plasminogen activator (u-PA) in endothelial cells as well as u-PA and its receptor in kidney epithelial cells. In this study, we report that human recombinant HGF stimulates expression of plasminogen activator inhibitor type 1 (PAI-1) and tissue factor (TF) in the human hepatoma cell line HepG2. PAI-1 antigen as determined by a specific enzyme-linked immunosorbent assay increased up to threefold in conditioned media of HepG2. This increase was dose dependent with maximum stimulation achieved with a concentration of 50 ng/mL of hepatocyte growth factor (HGF). PAI-1 antigen also increased up to fourfold in the extracellular matrix in HGF treated HepG2. The production of the PAI-1 binding protein vitronectin (Vn) was not affected by HGF. In contrast, TF activity in HepG2 treated with HGF increased up to twofold. As determined by Northern blotting, PAI-1 and TF-specific mRNA were increased significantly in the presence of HGF, whereas Vn mRNA was not affected. The increase in PAI-1 and TF mRNA was also seen when HepG2 were incubated with HGF in the presence of cycloheximide, thereby indicating that de novo protein synthesis is not required to mediate the effect. u-PA could be detected neither in unstimulated or HGF-stimulated HepG2 cells on the antigen level nor on the mRNA level. In conclusion, our data give evidence that HGF, in addition to its proliferative effect for different cell types, is also involved in the local regulation of fibrinolysis and coagulation. One could speculate that HGF might modulate processes requiring matrix degradation by increasing the expression of the protease u-PA in one cell type and by upregulating the expression of the serine protease inhibitor PAI-1 in a different cell type. Because u-PA has been shown to activate latent HGF to the active form, it could furthermore be speculated that by upregulating PAI-1, which in turn could inhibit u-PA, HGF might regulate its own activation.
肝细胞生长因子（HGF）在体外对大鼠和人类的肝细胞、上皮细胞及内皮细胞都是一种强大的促有丝分裂原，且在体内具有血管生成作用。它与纤溶酶原具有相当的同源性，并且已被证明可上调内皮细胞中的尿激酶型纤溶酶原激活物（u-PA）以及肾上皮细胞中的u-PA及其受体。在本研究中，我们报告人重组HGF可刺激人肝癌细胞系HepG2中1型纤溶酶原激活物抑制剂（PAI-1）和组织因子（TF）的表达。通过特异性酶联免疫吸附测定法测定，HepG2条件培养基中的PAI-1抗原增加了高达三倍。这种增加呈剂量依赖性，在肝细胞生长因子（HGF）浓度为50 ng/mL时达到最大刺激。在HGF处理的HepG2细胞的细胞外基质中，PAI-1抗原也增加了高达四倍。PAI-1结合蛋白玻连蛋白（Vn）的产生不受HGF影响。相反，用HGF处理的HepG2中的TF活性增加了高达两倍。通过Northern印迹法测定，在HGF存在下，PAI-1和TF特异性mRNA显著增加，而Vn mRNA不受影响。当HepG2在放线菌酮存在下与HGF一起孵育时，也观察到PAI-1和TF mRNA的增加，从而表明介导该效应不需要从头合成蛋白质。在未刺激或HGF刺激的HepG2细胞中，无论是在抗原水平还是mRNA水平都检测不到u-PA。总之，我们的数据表明，HGF除了对不同细胞类型具有增殖作用外，还参与纤维蛋白溶解和凝血的局部调节。可以推测，HGF可能通过增加一种细胞类型中蛋白酶u-PA的表达并上调另一种细胞类型中丝氨酸蛋白酶抑制剂PAI-1的表达来调节需要基质降解的过程。因为已证明u-PA可将潜伏的HGF激活为活性形式，所以还可以推测，通过上调PAI-1（进而抑制u-PA），HGF可能调节其自身的激活。
