Identification of expressed sequence tags of genes expressed highly in the activated hepatic stellate cell

Expressed sequence tags (ESTs) were generated from two 3'-directed cDNA libraries constructed from quiescent and activated rat hepatic stellate cell (HSC) to analyze the expression profiles of active genes in both cells. From quiescent and activated HSC, 694 ESTs and 779 ESTs, respectively, were obtained after excluding those having shorter than 30 bp. Among ESTs obtained from quiescent and activated HSC, 68 and 73 kinds of ESTs (186 clones and 236 clones), respectively, appeared more than once, implying that their genes are expressed highly in each cell type. 52 among 73 ESTs appeared only in the activated HSC, 47 among 68 ESTs only in the normal HSC, and 21 in both cells. The genes of these 52 ESTs were assumed to be expressed more highly in the activated HSC. To confirm the high expression of genes of which the ESTs appeared more than twice in the activated HSC, northern hybridization was carried out with RNAs derived from rat normal and fibrotic liver using each of 18 EST DNAs as probe. 13 ESTs showed more intense bands with RNA isolated from the fibrotic liver than normal liver. From these results, we confirm the positive correlation between abundance of transcript in activated HSCs and the expression level in fibrotic liver. The expression profile of the transcripts serves as an important tool in understanding the biological properties of HSC.