382 OSTEOPONTIN INDUCES DUCTULAR REACTION AND CONTRIBUTES TO LIVER FIBROSIS

Abstract

in 113 HBV infected liver tissues. Primary rat hepatic stellate cells (HSC) and the CFSC cell line were used to examine the effects of Notch ligands in liver fibrogenesis. Results: Microarray analyses revealed upregulated Notch-related genes, e.g. Jagged-1 and Jagged-2, in HBV associated fibrotic liver tissues. IHC demonstrated remarkable positive staining for three Notch ligands, Jagged1, Dll3 and Dll4, in cirrhotic liver tissues compared to controls. In addition, Jagged-1 and Dll4 were confirmed to localise in activated HSC, the main collagen producing liver cell type, by confocal microscopy. Dll4 and Jagged-1 staining displayed an opposing trend in HBV infected patients. Dll4 IHC score correlated with inflammatory grades (r = 0.60, P < 0.0001) and fibrotic stages (r = 0.68, P< 0.0001) in 113 HBV infected patients, whereas 69% of specimens from cirrhotic patients were Dll4 immunostaining negative. In contrast, sinusoidal cell positive Jagged-1 staining was mainly observed in cirrhotic patients (54%), but only 20% non-cirrhotic patients showed Jagged-1 positive staining in sinusoidal cells. In vitro, blocking Notch signalling by g-secretase inhibitor significantly reduced expression of collagen I in HSCs. Treatment of HSCs and CFSCs with recombinant Dll4 protein decreased TGF-b1-dependent collagen I and connective tissue growth factor (CTGF) expression. On the other hand, recombinant Jagged-1 protein incubation ameliorated the effects of Dll4 on collagen I and CTGF expression. Conclusions: Notch ligands contribute to liver fibrogenesis. Dll4 and Jagged-1 play opposing effects on the regulation of fibrosisassociated genes.