Background/aims: Halofuginone, an inhibitor of collagen synthesis, prevented and caused resolution of established hepatic fibrosis. A genomic approach in vivo was used to search for additional genes responsible for halofuginone mode of action.
Methods: Fibrosis was induced in rats by thioacetamide (TAA) and evaluated by collagen type I gene expression and the levels of collagen, tissue inhibitors of metalloproteinases-2 and smooth-muscle actin. Halofuginone was given in the diet. cDNA from liver biopsies was hybridized on Atlas arrays comprising of 588 genes. The results were confirmed by Northern blots and in situ hybridization.
Results: Insulin-like growth factor binding protein-1 (IGFBP-1) was one of the 13 genes differentially expressed in the fibrotic liver after halofuginone treatment. After 2 and 4 weeks, halofuginone prevented the TAA-induced down-regulation of IGFBP-1 gene expression. Halofuginone also prevented the TAA-dependent changes in IGFBP-3 gene expression. Halofuginone affected IGFBP-1 synthesis in rat hepatocytes and cells of hepatocyte origin and caused time- and dose-dependent increases in the IGFBP-1 gene expression and synthesis by HepG2 cells. The IGFBP-1 secreted by HepG2-inhibited stellate cell motility.
Conclusions: Halofuginone is an anti-fibrotic drug that inhibits collagen synthesis by stellate cells and preventing alteration in the synthesis of IGFBPs by hepatic cells.