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

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 496 bp 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.