Acceleration of liver regeneration by gene transfer with matrix metalloproteinase (MMP)-1

肝细胞外基质重塑被认为参与了肝再生。我们研究了在体内肝脏中胶原酶活性的增加是否可以诱导肝细胞增殖。用重组腺病毒Ad 5 MMP-1基因转移胶原酶诱导肝细胞BrdU标记指数和有丝分裂指数显著增加，导致肝干重增加，而对照腺病毒Ad 5LacZ的影响最小。Ad 5 MMP-1感染后48小时左右肝细胞开始增殖，2周时基本结束。在Ad 5 MMP-1感染后还检测到一过性肝损伤，表现为AST、ALT和LDH升高，峰值在1周左右，并伴有肝细胞凋亡。胶原酶诱导肝细胞增殖过程中的重要现象是糖原合成酶激酶（GSK）-3β丝氨酸残基磷酸化、β-catenin在肝细胞胞浆中的积聚以及E-cadherin表达的短暂性降低。 关于我们 ssion进行观察。因此，我们报道了胶原酶对肝细胞外基质的修饰在体内诱导了短暂的肝细胞增殖，这表明肝细胞外基质本身的状况在调节肝细胞增殖中起着关键作用。我们推测，肝纤维性瘢痕未能消退是由于间质胶原酶过少（MMP-1或MMP-13）和过多ECM和TIMP。我们通过在大鼠持续性肝纤维化模型中使用基因治疗来传递MMP-1，从而短暂改变平衡，从而验证了这一假设。在感染Ad 5 MMP-1的大鼠中，而在感染Ad 5LacZ的大鼠中，纤维化在感染后2周显著减弱。有趣的是，在Ad 5 MMP-1感染的大鼠中，活化的肝星状细胞的数量也减少。此外，只有在Ad 5 MMP-1处理的大鼠中观察到肝小梁的解体、肝细胞大小的异质性和肝干重的增加，这表明MMP-1刺激肝细胞增殖，这通过BrdU染色证实。我们的研究结果表明，短暂的MMP-1在肝脏中的过度表达有效地减弱建立纤维化和诱导肝细胞增殖。少

Remodeling of hepatic extracellular matrix has been supposed to participate in liver regeneration. We investigated whether increased activity of collagenase in the liver could induce hepatocyte proliferation in vivo. Gene transfer of collagenase with a recombinant adenovirus Ad5MMP-1 induced significant increase in BrdU labeling index and mitotic index in hepatocytes, leading to an increased dried liver weight, while a control adenovirus, Ad5LacZ, had a minimal effect. Hepatocyte proliferation started around 48hr after the infection with Ad5MMP-1 and almost ended at 2weeks. Transient liver injury indicated by increased AST, ALT, and LDH with peaks around 1 week was also detected after Ad5MMP-1 infection, accompanied by apoptosis in hepatocytes. As important phenomena during collagenase-induced hepatocyte proliferation, phosphorylation of glycogen synthase kinase (GSK)-3β at serine residue, accumulation of β-catenin in cytoplasm of hepatocytes, and transient decrease in E-cadherin expre … More ssion were observed. Thus, we report that modification of hepatic extracellular matrix by collagenase induces transient hepatocyte proliferation in vivo, suggesting that the condition of hepatic extracellular matrix per se plays a pivotal role in regulating hepatocyte proliferation.In another experiment, we hypothesized that failure to resolve the hepatic fibrous scar results from the imbalance between too little interstitial collagenases (MMP-1 or MMP-13) and too much ECM and TIMPs. We tested this hypothesis by transiently changing the balance by using gene therapy to deliver MMP-1 in a rat model of persistent liver fibrosis. In Ad5MMP-1 infected, but not in Ad5LacZ infected, rats the fibrosis was dramatically attenuated at 2 weeks after the infection. Interestingly, the number of activated hepatic stellate cells was also decreased in Ad5MMP-1 infected rats. Moreover, disorganization of hepatic trabecule, heterogeneity in size of hepatocytes, and increased dried liver weight were observed only in Ad5MMP-1 treated rats, suggesting that MMP-1 stimulated hepatocyte proliferation, which was confirmed by BrdU staining. Our findings demonstrate that transient MMP-1 overexpression in the liver effectively attenuates established fibrosis and induces hepatocyte proliferation. Less