Differential expression of keratan sulphate proteoglycans fibromodulin, lumican and aggrecan in normal and fibrotic rat liver.

In this study we investigated in rat liver the expression of genes coding for the core proteins of fibromodulin, lumican and aggrecan. By means of Northern analysis and in situ hybridization we present evidence for their differential transcription during liver fibrogenesis. Whereas no fibromodulin expression could been detected, both lumican and aggrecan transcripts were found displaying different time-courses of expression during the fibrogenic process. Based on studies performed in non-hepatic tissues, these proteoglycans are considered to have keratan sulphate glycosaminoglycan side chains. The expression of the respective core protein genes in liver is unexpected since published data have shown neither keratan sulphate nor its synthesis de novo in this tissue. The results also point to a putative role of aggrecan in the modulation of the inflammatory process in the liver.