Structure-based drug design of 11β-hydroxysteroid dehydrogenase type 1 inhibitors

The enzyme 11β-Hydroxysteroid Dehydrogenase 1 (11β-HSD1) catalyses the intracellular biosynthesis of the active glucocorticoid cortisol. Tissue specific dysregulation of the enzyme has been implicated in the development of metabolic syndrome and other associated diseases. Experiments with transgenic mice and prototype inhibitors show that inhibition of 11β-HSD1 in visceral adipose tissue and liver leads to a resistance of diet-induced hyperglycemia and a favourable lipid and lipoprotein profile as compared to controls. 11β-HSD1 inhibition has thus been proposed as an effective strategy to decrease intracellular glucocorticoid levels without affecting circulating glucocorticoid levels that are essential for stress responses. The clinical development of selective and potent drugs has therefore become a priority. In this research, a process of virtual screening employing the novel algorithm UFSRAT (Ultra Fast Shape Recognition with Atom Types) was used to discover compounds which had specific physicochemical and spatial atomic parameters deemed essential for inhibition of 11β-HSD1. The top scoring compounds were assayed for inhibitory activity against recombinant human and mouse enzyme, using a fluorescence spectroscopy approach. In addition, HEK-293 cell based assays with either human, mouse or rat enzymes were carried out using a scintillation proximity assay (SPA). The most potent compound competitively inhibited human 11β-HSD1 with a Kiapp value of 51 nM. Recombinant mouse and human enzyme were expressed, purified and characterised and used in a series of ligand binding assays. Further to this, an X-ray crystal structure of mouse 11β-HSD1 in complex with a tight binding inhibitor – carbenoxolone was solved