High-throughput tandem-microwell assay for ammonia repositions FDA-Approved drugs to Helicobacter pylori infection

To date, little attempt has been made to develop new treatments for Helicobacter pylori ( H. pylori ), although the community is aware of the shortage of treatments for H. pylori . In this study, we developed a 192-tandem-microwell-based high-throughput-assay for ammonia that is a known virulence factor of H. pylori and a product of urease. We could identify few drugs, i.e. panobinostat, dacinostat, ebselen, captan and disulfiram, to potently inhibit the activity of ureases from bacterial or plant species. These inhibitors suppress the activity of urease via substrate-competitive or covalent-allosteric mechanism, but all except captan prevent the antibiotic-resistant H. pylori strain from infecting human gastric cells, with a more pronounced effect than acetohydroxamic acid, a well-known urease inhibitor and clinically used drug for the treatment of bacterial infection. This study offers several bases for the development of new treatments for urease-containing pathogens and to study the mechanism responsible for the regulation of urease activity. * Abbreviations : AHA : acetohydroxamic acid CBS : cystathionine beta-synthase CSE : cystathionine γ-lyase DTT : dithiothreitol EBS : ebselen FAD : Foreign Approved Drugs FDA : U.S. Food and Drug Administration H. pylori : Helicobacter pylori HPU : H. pylori urease HTS : high-throughput screening JBU : jack bean urease KD : equilibrium dissociation constant LB : Luria-Bertani liquid medium MICs : minimum inhibitory concentrations O. anthropi : Ochrobactrum anthropi OAU : Ochrobactrum anthropic urease P. mirabilis : Proteus mirabilis SPR : surface plasmon resonance.