Invited talk (7): 4:50 p.m. - 5:25 p.m.
Drug Discovery Based on Genome Information
Speaker
Gozoh Tsujimoto, Professor, Graduate School of Pharmaceutical Sciences, Kyoto University, Japan
Abstract
The most important strategies in pharmacogenomics are gene expression profiling and the network analysis of human disease models. In this talk, I would like to show two examples. (1) Glomerulonephritis (GN) is a progressive inflammation that may be caused by a variety of underlying disorders. It is the primary cause of chronic renal failure and end-stage renal disease, which require dialysis and transplantation worldwide. Immunosuppressive therapy has been used to treat GN clinically, but this treatment has had insufficient therapeutic effects. Here, we show that protein kinase CK2 is a key molecule in the progression of GN. cDNA microarray analysis identified CK2alpha, the catalytic subunit of CK2, as a GN-related, differentially expressed gene. Overexpression of CK2alpha was noted in the proliferative glomerular lesions in rat GN models and in renal biopsy specimens from lupus nephritis or IgA nephropathy patients. Administration of either antisense oligodeoxynucleotide against CK2alpha or low molecular weight CK2-specific inhibitors effectively prevented the progression of renal pathology in the rat GN models. The resolution of GN by CK2 inhibition may result from its suppression of extracellular signal-regulated kinase-mediated cell proliferation, and its suppression of inflammatory and fibrotic processes that are enhanced in GN. Our results show that CK2 plays a critical role in the progression of immunogenic renal injury, and therefore, CK2 is a potential target for GN therapy. (2)Diabetes, a disease in which the body does not produce or use insulin properly, is a serious global health problem. Gut polypeptides secreted in response to food intake, such as glucagon-like peptide-1 (GLP-1), are potent incretin hormones that enhance the glucose-dependent secretion of insulin from pancreatic beta cells. Free fatty acids (FFAs) provide an important energy source and also act as signaling molecules in various cellular processes, including the secretion of gut incretin peptides. Here we show that a G-protein-coupled receptor, GPR120, which is abundantly expressed in intestine, functions as a receptor for unsaturated long-chain FFAs. Furthermore, we show that the stimulation of GPR120 by FFAs promotes the secretion of GLP-1 in vitro and in vivo, and increases circulating insulin. Because GLP-1 is the most potent insulinotropic incretin, our results indicate that GPR120-mediated GLP-1 secretion induced by dietary FFAs is important in the treatment of diabetes. In both studies, bioinfomatics is of most importance for us to find out candidate genes for drug discovery.