The central goal of this project is to identify potent and specific small molecule ligands to the orphan nuclear receptor RORalpha (NR1F1). As a drug target, RORalpha has the potential to address pathological factors in the pre-diabetic metabolic syndrome and in atherosclerosis. RORalpha has a ligand-binding pocket typical of nuclear receptors, but pharmacologically active small molecule ligands have not been identified as yet. Mice with a homozygous inactivation of RORalpha have a complex phenotype that includes an exaggerated response to ischemia, increased susceptibility to diet-induced atherosclerosis, and altered energy metabolism. At the molecular level, RORalpha is sharply induced by hypoxia and can suppress inflammatory markers in vascular smooth muscle cells, consistent with its role in atherogenesis. Testing of potent and specific compounds in animal models of disease is a critical next step in defining its therapeutic potential. We propose (i) to screen a focused library of 20,000 compounds in an optimal, cell based assay of transcriptional activity; (ii) develop a binding assay to exclude false positives and confirm hits; and (iii) identify a series of related, active compounds to further substantiate the viability of RORalpha as a target for drug development. Nuclear receptors have a very high success rate for development of new categories of drug. These Phase 1 studies will provide the foundation for the selection, design and synthesis of ligands to characterize RORalpha as a drug target in models of metabolic disease and atherosclerosis.
