The primary role of insulin is glucose homeostasis. The beta-cells of the endocrine pancreatic islets function to synthesize, store and secrete insulin. Elevated plasma glucose stimulates the beta-cell to acutely deploy preformed insulin-containing secretory granules that rapidly undergo regulated exocytosis, releasing insulin into the periphery. In order to restore the depleted intracellular stores of insulin, glucose also stimulates the biosynthesis of pro-insulin, processing enzymes, and a number of other unidentified cytosolic and secretory granule-associated proteins. Complex metabolic pathways that have been uniquely adapted to the beta-cell tightly regulate each of these steps. The beta-cells play a pivotal role in the pathophysiology of both Type 1 and Type 2 diabetes. During the past few years, dramatic improvements have been made in techniques for the global evaluation of cellular gene expression such as differential display and microarray analyses. Unfortunately however, such techniques often result in the production of highly complex data sets that must be organized through the use of computer models to group expressed genes into a comprehensible pattern. Therefore, a primary organizational scheme would be of great value to parse the data into functionally relevant groupings. The cell itself actually provides such an organizational structure. All mRNAs copied from all genes are processed through a series of steps to modify, splice, transport, degrade, stabilize, store, or translate the mRNAs. The experiments described in this application utilize Ribonomics' novel technology to rapidly isolate unique subsets of mRNAs that are clustered in functionally related pathways. As we will describe, this technology will allow us to; 1) better define the current understanding of signaling and metabolic pathways in the beta-cell; and 2) allow us to identify previously unknown components involved in beta-cell-specific functions. These efforts will produce a list of candidate therapeutic targets for the treatment of diabetes.
