Overexpression of MMP-1 significantly degrades type I collagen in human hepatic stellate cells

ObjectiveTo construct recombinant vector carrying interstitial collagenase (MMP-1) and investigate whether the expression of collagen I and other extracellular matrix ingredients could be inhibited in human hepatic stellate cell (LX-2) by overexpressing MMP-1 in vitro.MethodsThe plasmid expressing MMP-1 (dl6-95-MMP1) was constructed through inserting the full length of MMP-1 gene into the AAV vector dl6-95 which includes the ITR of AAV. Then,dl6-95-MMP1 or dl6-95 plasmid was transfected into LX-2 after 7 days. The levels of MMP-1,collagen I and TIMP-1 mRNAs and proteins were analyzed by real time PCR and Western blotting. Results The plasmid expressing MMP-1 (dl6-95-MMP-1) was constructed successfully. After dl6-95-MMP-1 plasmid was transfected into LX-2,real time PCR results showed that the level of MMP-1 mRNA increased significantly compared with LX-2 transfected with dl6-95 plasmid (without MMP-1),whereas the transcription of collagen I and TIMP-1 mRNA had not changed. Western blot results showed that MMP-1 increased significantly. After transfected with dl6-95-MMP-1,the expression of collagen I was inhibited significantly,while the expression of TIMP-1 was not significantly changed.ConclusionMMP-1 overexpression in LX-2 could inhibit the expression of collagen I significantly. This inhibition was mainly through degrading collagen I protein,other than through down-regulating the transcription of collagen I and TIMP-1 mRNA or inhibiting the expression of TIMP-1 protein.