Glucose homeostasis is strongly influenced by metabolic flux through the central anaplerotic enzyme, pyruvate carboxylase (PC). Many studies have implicated PC activity in hepatic glucose release, beta cell insulin release and beta cell proliferation. As such, PC plays an important role in regulating blood glucose levels and aberrant PC activity is correlated with type-2 diabetes. Remarkably, despite its critical role in central metabolism and its connection to several human diseases, there are no known potent or specific pharmacological modulators of PC activity. This project seeks to develop chemical probes directed against PC that will assist fundamental research on enzyme function and cellular metabolism. Such probes may ultimately facilitate the development of new therapeutics designed to mitigate the effects of diseases such as type-2 diabetes. PC effectors will be developed and characterized using two independent but highly complementary approaches: (1) Using a structure-based drug design approach, an extended structure-activity relationship will be developed for a promising lead compound that binds to the carboxyltransferase domain active site with low M affinity; (2) In parallel, high throughput screening will be initiated with a ~100 000 compound library to expand the range of target sites, chemical scaffolds and effector types among the lead compounds. The most promising compounds from both approaches will be assessed for potency and specificity using a suite of kinetic assays, and structurally characterized by computational docking and X-ray crystallography. The approach is highly compatible with the integration of undergraduate students in an inter-disciplinary research team that offers exposure to medicinal chemistry, protein biochemistry and structural biology. This project will result in a first-ever set of chemical probes directed against PC that will serve as powerful new tools to modulate central metabolism in studies of beta cell function and glucose homeostasis.
Pyruvate carboxylase is an essential central metabolic enzyme that has been implicated in a range of human health disorders, including type-2 diabetes and cancer. Despite its important role in maintaining the body's energy balance, it has never been explored as a drug target. We will develop small molecules that are potent and specific inhibitors and activators of pyruvate carboxylase, with the expectation that these will serve as new chemical probes for basic research.
