Cloning of the rat ADAMTS-1 gene and its down regulation in endothelial cells in cirrhotic rats


Ioannis Diamantis M.D., Ph.D., Department of Gastroenterology Inselspital, CH-3010 Berne, Switzerland


Abstract:Aims: This study was undertaken in order to identify genes which are regulated during the process of liver fibrosis. Methods: The differential display method and RNA from rat endothelial cells before and after induction of cirrhosis were used. Results: A 496bp fragment, which was down regulated in liver endothelial cells from a cirrhotic animal, was cloned. The cloned fragment showed a 95% homology with the newly cloned mouse ADAMTS-1 gene (a disintegrin and metalloproteinase with thrombospondin motifs), which is implicated in inflammation. The fragment was found to span the 3′ of exon 6, the whole exon 7 and the 5′ of exon 8. Sequencing of the entire coding region of the rat gene showed a 94% homology at the nucleic acid level and 96% homology at the amino acid level. The sequences responsible for the function of the protein were conserved. Northern blot analysis, using the cloned fragment as a probe, confirmed the finding that the gene was down-regulated in endothelial cells derived from livers of cirrhotic animals. In situ PCR analysis localised the ADAMTS-1 gene in the liver endothelial cells from normal animals. Conclusions: Regulation of the expression of genes which belong to the metalloproteinase family in liver endothelial cells might be important in the development of liver cirrhosis.