system
Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: OBJECTIVE, METHODS, RESULTS. Meshes: Animals, Apoptosis, Bile Acids and Salts, Biological Transport, Cathepsin B, Cell Nucleus, Cells, Cultured, Liver, Male, Rats, Rats, Sprague-Dawley.
user
Does cathepsin B contribute to bile salt-induced apoptosis of rat hepatocytes? Context: Bile salt-induced apoptosis is mediated by a trypsin-like nuclear protease. The aims of this study were to identify this protease and to elucidate its mechanistic role in bile salt-induced hepatocyte apoptosis. Rats, isolated rat hepatocytes, and a rat hepatoma cell line stably transfected with a bile salt transporter (McNtcp.24) were used for this study. In the bile duct-ligated rat, a threefold increase in apoptosis and a fourfold increase in trypsin-like nuclear protease activity were observed. The nuclear protease activity was purified from bile duct-ligated rats and identified as cathepsin B. Specific, structurally dissimilar cathepsin B inhibitors blocked glycochenodeoxycholate (GCDC)-induced apoptosis in cultured rat hepatocytes. Furthermore, stable transfection of McNtcp.24 cells with the complementary DNA for cathepsin B in the antisense orientation reduced cathepsin B activity and GCDC-induced apoptosis by >75%. Next, cathepsin B cellular localization during apoptosis was determined by immunoblot analysis of nuclear cell fractions, immunocytochemistry, and by determining the compartmentation of expressed cathepsin B fused to green fluorescent protein. All three approaches showed translocation of cathepsin B from the cytoplasm to the nucleus during GCDC-induced apoptosis.
assistant
The data suggest that translocation of cathepsin B from the cytoplasm to the nucleus is a mechanism contributing to bile salt-induced apoptosis of hepatocytes. Final Decision: yes