LAMININ-RICH EXTRACELLULAR-MATRIX MAINTAINS HIGH-LEVEL OF HEPATOCYTE NUCLEAR FACTOR-4 IN RAT HEPATOCYTE CULTURE

Laminin-rich extracellular matrix, EHS-gel, has been demonstrated to k eep a high level of liver-specific gene expression in cultured rat hep atocytes. To obtain information about the effect of EHS-gel on liver-s pecific functions, gene expression of liver-enriched transcription fac tors in rat hepatocytes was investigated. The apolipoprotein A-I and a lbumin mRNA levels were higher in hepatocytes cultured on EHS-gel than in those cultured on type I collagen (TIC). The levels of mRNA for HN F-4, C/EBP alpha and C/EBP beta were also higher on EHS-gel than on TI C. The level of HNF-4 mRNA in hepatocytes on EHS-gel was almost compar able to that in liver. The HNF-3 alpha mRNA level was lower on EHS-gel than on TIC. C/EBP beta mRNA was induced by dexamethasone in both EHS -gel and TIC. The induction of C/EBP alpha and HNF-4 by dexamethasone was observed only on TIC. These data suggest that EHS-gel leads hepato cytes to keep the phenotypic expression through high expression of liv er-enriched transcription factors, such as HNF-4. (C) 1995 Academic Pr ess, Inc.