Title : New indications for FDA-approved drugs: Selective inhibition of the growth of Helicobacter pylori by covalent allosteric regulation of urease
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 and the increase in drug resistance of gram-negative bacteria. Thus, there is an unmet need to identify new potent inhibitors with a safe profile to control H. pylori. In this study, we developed a high-throughput assay for urease, an enzyme that is a known virulence factor of H. pylori. The assay is established on a previously-reported 192-tandem-well plate for gas-releasing enzymes. After executing a high-throughput screening of 1,563 clinically approved drugs with this assay, we identified three drugs that could potently inhibit the urease of jack bean, H. pylori and Ochrobactrum anthropic. The newly identified inhibitors, have an IC50 of 0.4 mM and 2.3 mM, and are ~400 and 70-fold more potent than acetohydroxamic acid (AHA), a well-known urease inhibitor and clinically used drug for the treatment of bacterial infection. Interestingly, a consistently new mode of action was found to rely on covalently and allosterically modifying the non-active-site Cys residue. These drugs as well as its newly synthesized derivatives could inhibit the growth of H. pylori much more efficiently than AHA, without affecting the growth of the urease-negative E. coli strain, and prevent H. pylori infection of human gastric cells. This study offers several bases for repurposing the old drugs to develop new treatments for urease-containing pathogens and to study the mechanism responsible for the regulation of urease activity.
Audience take away:
• Cutting-edge technology and knowledge on assay development and high-throughput screening
• A newly developed tandem-well-based assay for NH3-producing enzymes
• New indications of two clinically used drugs on inhibiting the growth and infection of H. pylori