Indomethacin-Amides As Molecular Scaffolds To Investigate The Structure and Function of Cyclooxygenases, Thromboxane Synthase, and Sterol 14-alpha Demethylase From Trypanosoma Cruzi

Abstract

Indomethacin (INDO) has been a commercially available non-steroidal anti-inflammatory drug since 1963. As such, INDO has well-defined toxicology and pharmacokinetics that allow it to serve as a known molecular scaffold that can be subtly modified to explore the structure and function of multiple enzyme systems. Neutralization of the INDO scaffold by amidation affords an inhibitor that is selective for cyclooxygenase-2 (COX-2) over COX-1. By utilizing newly synthesized INDO-amides, we report that a second-shell residue, residue472, is a molecular determinant for this selectivity via its influence on dynamic motions of active site residue Glu524. Additionally, we report this residue is also a molecular determinant of the competency of a COX isoform to oxygenate 2-arachidonoyl glycerol (2-AG). As such, we have determined that a COX-1 (mouse), contrary to previous reports, can oxygenate the endocannabinoid 2-AG. We also report the design and synthesis of dual inhibitors of thromboxane synthase (TXAS) and COX-2. We have conferred TXAS inhibition through the addition of an amide group containing alkyl linkers of varying lengths and various positional isomers of the pyridyl moiety. As such, we have improved upon the previously reported structure activity relationship of TXAS inhibitors which demanded the presence of a free carboxylate and only a 3-pyridyl moiety. Lastly, we have used INDO-amides as inhibitors of sterol 14-ƒÑƒndemethylase (CYP51) from the parasite Trypanosoma cruzi (TC). Infection by TC causes Chagas disease in Latin American countries. With these compounds, have been able to retard parasite growth in cardiomyocytes.