Proteome analysis of rat hepatic stellate cells

Proteome analysis was performed on cellular and secreted proteins of normal (quiescent) and activated rat hepatic stellate cells. The stellate cells w ere activated either in vitro by cultivating quiescent stellate cells for 9 days or in vivo by injecting rats with carbon tetrachloride for 8 weeks. A total of 43 proteins/polypeptides were identified, which altered their exp ression levels when the cells were activated in vivo and/or in vitro, Twent y-seven of them showed similar changes in vivo and in vitro, including up-r egulated proteins such as calcyclin, calgizzarin, and galectin-1 as well as down-regulated proteins such as liver carboxylesterase 10 and serine prote ase inhibitor 3, Sixteen of them showed different expression levels between in vivo and in vitro activated stellate cells. These results were reproduc ibly obtained in 3 independent experiments, The up-regulation of calcyclin, calgizzarin, and galectin-1, as well as the down-regulation of liver carbo xylesterase 10 were directly confirmed in fibrotic liver tissues. Northern blots confirmed up-regulation of the messenger RNAs (mRNAs) of calcyclin, c algizzarin, and galectin-1 in activated stellate cells, indicating that the se changes were controlled at the mRNA level. In addition a list compiling over 150 stellate cell proteins is presented. The data presented here thus provide a significant new protein-level insight into the activation of hepa tic stellate cells, a key event in liver fibrogenesis.