Development of Carbonic Anhydrase Inhibitors for Drug Discovery Against Neisseria gonorrhoeae

Neisseria gonorrhoeae is a Gram-negative pathogen that causes gonorrhea, a venereal disease that is becoming increasingly difficult to treat as antibiotic resistance increases worldwide. The CDC currently only recommends one drug to treat gonococcal infection, highlighting the need for the development of new therapeutics. To combat this public health crisis, we developed novel inhibitors that target the N. gonorrhoeae carbonic anhydrases, a family of metalloenzymes that catalyze the conversion of carbon dioxide to bicarbonate, which is necessary for several physiological processes. Our drug design strategy is centered on repurposing the scaffolds of ethoxzolamide (EZM) and acetazolamide (AZM), FDA-approved human carbonic anhydrase inhibitors with efficacy toward N. gonorrhoeae. The work herein describes our efforts to investigate the properties of EZM- and AZM-based derivatives to improve antimicrobial effects. First, we generated EZM analogs that were metabolically stable, which in turn improved in vivo PK properties and resulted in two lead compounds that reduced gonococcal infection in an infected mouse model by 90-95%. Secondly, we developed a structure-activity relationship for AZM analogs, in which we found compounds with hydrophobic six-membered rings as R-groups to be the most potent. One of these analogs was also found to reduce gonococcal infection in vivo by approximately 98%. Lastly, an accumulation assay was utilized to begin understanding the physicochemical properties of AZM analogs that influence a molecule’s concentration within the bacterial cell and how that affects activity. In sum, this dissertation investigated novel carbonic anhydrase inhibitors that showed efficacy against N. gonorrhoeae both in vitro and in vivo, while also determining how slight modifications to the scaffolds can greatly affect PK/ADME properties and intracellular accumulation. These findings will be used to inform future drug design towards developing agents with anti-gonococcal therapeutic potential.