An amiloride derivative is active against the F1Fo-ATP synthase and cytochrome bd oxidase of Mycobacterium tuberculosis

Kiel Hards,Julian D Langer,Benjamin J Buckley,Richard S Bujaroski,Kyu Y Rhee,Michael J Kelso,Laura M Keighley ,Kurt L Krause ,Liam K Harold,Erik J Hasenoehrl,Michael Berney,Ayana Menorca,Laura Preiß ,Matthew B Mcneil,Helen K Opel-Reading,Cara Adolph,Joel D A Tyndall,Natalie Je Waller ,Thomas Meier,Chen‐Yi Cheung ,Zhi Shean Tee,Gregory M Cook

doi:10.1038/s42003-022-03110-8

Abstract

Increasing antimicrobial resistance compels the search for next-generation inhibitors with differing or multiple molecular targets. In this regard, energy conservation in Mycobacterium tuberculosis has been clinically validated as a promising new drug target for combatting drug-resistant strains of M. tuberculosis. Here, we show that HM2-16F, a 6-substituted derivative of the FDA-approved drug amiloride, is an anti-tubercular inhibitor with bactericidal properties comparable to the FDA-approved drug bedaquiline (BDQ; Sirturo®) and inhibits the growth of bedaquiline-resistant mutants. We show that HM2-16F weakly inhibits the F1Fo-ATP synthase, depletes ATP, and affects the entry of acetyl-CoA into the Krebs cycle. HM2-16F synergizes with the cytochrome bcc-aa3 oxidase inhibitor Q203 (Telacebec) and co-administration with Q203 sterilizes in vitro cultures in 14 days. Synergy with Q203 occurs via direct inhibition of the cytochrome bd oxidase by HM2-16F. This study shows that amiloride derivatives represent a promising discovery platform for targeting energy generation in drug-resistant tuberculosis.

Highlights

Increasing antimicrobial resistance compels the search for next-generation inhibitors with differing or multiple molecular targets
This study shows that amiloride derivatives represent a promising discovery platform for targeting energy generation in drugresistant tuberculosis
We recently demonstrated that the cytochrome bd inhibitor ND-011992 strongly synergizes with Q203 and the combination can kill antibiotic-tolerant hypoxic M. tuberculosis[22]

Summary

Introduction

Increasing antimicrobial resistance compels the search for next-generation inhibitors with differing or multiple molecular targets. In this regard, energy conservation in Mycobacterium tuberculosis has been clinically validated as a promising new drug target for combatting drugresistant strains of M. tuberculosis. We show that HM2-16F, a 6-substituted derivative of the FDA-approved drug amiloride, is an anti-tubercular inhibitor with bactericidal properties comparable to the FDA-approved drug bedaquiline (BDQ; Sirturo®) and inhibits the growth of bedaquiline-resistant mutants. BDQ targets the energy-generating machinery (F1Fo-ATP synthase) of M. tuberculosis[7,8] marking energy generation a compelling target space for antimicrobial drug development[9]. BDQ dissipates the ΔpH component of the proton-motive force in mycobacteria[17,18] This depends on the target-based accumulation of BDQ and leads to an uncoupled microenvironment around the F1Fo-ATP synthase[18]. Telacebec® (Q203;20), has been developed as an inhibitor of M

Methods

Results

Conclusion