[Mechanism of hepatic stellate cell migration during liver fibrosis].

ABSTRACT

OBJECTIVE: To study the mechanism of migration of hepatic stellate cells (HSCs) within the space of Disse microenvironment during liver fibrosis, and to explore the novel pathogenesis of liver fibrosis from the view of cell migration. METHODS: Human HSCs of the line LX2-HSC were cultured. A modified in vitro Boyden chamber system was used to partially mimic the microenvironment of Disse space of normal basement membrane like matrix or that in fibrosis. HSCs were put in the upper chamber, and transforming growth factor (TGF)-beta1, plate-derived growth factor (PDGF)-BB, epidermal growth factor (EGF), vascular epithelial growth factor (VEGF), bfibroblast growth factor (bFGF), and collagen type I or type IV were put into the lower chamber. Four hours later cell migration assay was conducted. HSCs were put into 6-well plate and then added with TGF-beta1, PDGF-BB, EGF, VEGF, bFGF, and collagen type I or type IV, zymography was used to examine the activity of matrix metalloproteinases 2 and 9. SDS-gel immunoblotting was used too. RESULTS: Stimulation of HSCs with PDGF-BB, TGF-beta1, and/or EGF resulted in an increase in their migratory capacity and up-regulated MMP-2 activity. And the increase of MMP-2 could enhance Migration of HSC by 4.9-fold. The migration of HSCs (3.2-fold) was induced by type I collagen and inhibited by type IV collagen (1.2-fold). Migration induced by PDGF-BB, TGF-beta1, and collagen I could be inhibited by alpha1- and/or alpha2-integrin blocking antibodies. CONCLUSION: In liver fibrosis, alterations within the space of Disse microenvironment facilitate the migration of HSCs; the mechanism is associated with up-regulation of MMP-2 and with mediation of alpha1beta1 and alpha2beta1 integrins. Extracellular matrix by it self shows feedback actions to migration of HSCs.