Overexpression of MMP-13 Inhibited Collagen I Expression in Rat Hepatic Stellate Cells

Objective Liver fibrosis is characterized by increased deposition and altered composition of extracellular matrix. The aim of this study was to construct recombinant vector carrying interstitial collagenase(MMP-13) and investigate if the expression of collagen I could be inhibited in rat hepatic stellate cell(HSC) overexpressing MMP-13 in vitro. Methods The plasmid expressing MMP-13(dl6-95-MMP-13) was constructed through inserting the full length of MMP-13 gene into the AAV vector dl6-95 which includes the ITR of AAV. Then,dl6-95-MMP-13 or dl6-95 plasmid was transfected into HSC for 7 days. The level of MMP-13 and collagen I mRNAs and proteins were analyzed by real time PCR and Western blotting. Results The plasmid expressing MMP-13(dl6-95-MMP-13) was constructed successfully. After dl6-95-MMP-13 plasmid was transfected into HSC for 7 days,real time PCR results showed that the level of MMP-13 mRNA increased significantly compared with HSC transfected with dl6-95 plasmid(without MMP-13),whereas the transcription of collagen I had only slight increase. Western blotting results showed that both the pro-MMP-13 and active MMP-13 increased significantly,especially the active form of MMP-13. After transfected with dl6-95-MMP-13,the expression of collagen I was inhibited significantly. Conclusion MMP-13 overexpression in HSC could inhibit the expression of collagen I significantly. This inhibition occurred mainly through degradation of collagen I protein,rather than through regulating the transcription of collagen I.