Two-Way Regulation of MmpL3 Expression Identifies and Validates Inhibitors of MmpL3 Function in Mycobacterium tuberculosis

  • ACS Infect Dis. 2021 Jan 8;7(1):141-152. doi: 10.1021/acsinfecdis.0c00675.
Shipra Grover  1 ,  Curtis A Engelhart  1 ,  Esther Pérez-Herrán  2 ,  Wei Li  3 ,  Katherine A Abrahams  4 ,  Kadamba Papavinasasundaram  5 ,  James M Bean  6 ,  Christopher M Sassetti  5 ,  Alfonso Mendoza-Losana  2 ,  Gurdyal S Besra  4 ,  Mary Jackson  3 ,  Dirk Schnappinger  1
Affiliations
  • 1. Department of Microbiology and Immunology, Weill Cornell Medicine, New York, New York 10065, United States.
  • 2. TB Research Unit, Global Health R&D, GlaxoSmithKline, Severo Ochoa 2, Tres Cantos, Madrid 28760, Spain.
  • 3. Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado 80523, United States.
  • 4. Institute of Microbiology and Infection, School of Biological Sciences, University of Birmingham, Birmingham B15 2TT, U.K.
  • 5. Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, Massachusetts 01655, United States.
  • 6. Sloan Kettering Institute, New York, New York 10065, United States.
PMID: 33319550 DOI: 10.1021/acsinfecdis.0c00675
Abstract

MmpL3, an essential mycolate transporter in the inner membrane of Mycobacterium tuberculosis (Mtb), has been identified as a target of multiple, chemically diverse antitubercular drugs. However, several of these molecules seem to have secondary targets and inhibit Bacterial growth by more than one mechanism. Here, we describe a cell-based assay that utilizes two-way regulation of MmpL3 expression to readily identify MmpL3-specific inhibitors. We successfully used this assay to identify a novel guanidine-based MmpL3 inhibitor from a library of 220 compounds that inhibit growth of Mtb by largely unknown mechanisms. We furthermore identified inhibitors of cytochrome bc1-aa3 oxidase as one class of off-target hits in whole-cell screens for MmpL3 inhibitors and report a novel sulfanylacetamide as a potential QcrB inhibitor.

Keywords
antibiotics; drug discovery; molecular genetics; mycolic acids; respiration; targeted whole-cell screen.
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