2. Academic Validation
  3. Nitric Oxide-Dependent Electron Transport Chain Inhibition by the Cytochrome bc1 Inhibitor and Pretomanid Combination Kills Mycobacterium tuberculosis

Nitric Oxide-Dependent Electron Transport Chain Inhibition by the Cytochrome bc1 Inhibitor and Pretomanid Combination Kills Mycobacterium tuberculosis

  • Antimicrob Agents Chemother. 2021 Aug 17;65(9):e0095621. doi: 10.1128/AAC.00956-21.
Sheng Zeng  # 1 2,  Jingran Zhang  # 1 2 3,  Mingwei Sun 4,  Xiaofei Zhang 4 5 6,  Gregory M Cook 7 8,  Tianyu Zhang 1 2 6
Affiliations

Affiliations

  • 1 State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China.
  • 2 Guangdong-Hong Kong-Macao Joint Laboratory of Respiratory Infectious Diseases, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China.
  • 3 School of Life Sciences, University of Science and Technology of China, Hefei, China.
  • 4 Center for Cell Lineage and Atlas (CCLA), Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, China.
  • 5 CAS Key Laboratory of Regenerative Biology, Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China.
  • 6 University of Chinese Academy of Sciences, Beijing, China.
  • 7 Department of Microbiology and Immunology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand.
  • 8 Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland, New Zealand.
  • # Contributed equally.
PMID: 34152815 DOI: 10.1128/AAC.00956-21
Abstract

Mycobacterium tuberculosis, the causative agent of human tuberculosis, harbors a branched electron transport chain, preventing the bactericidal action of cytochrome bc1 inhibitors (e.g., TB47). Here, we investigated, using luminescent mycobacterial strains, the in vitro combination activity of cytochrome bc1 inhibitors and nitric oxide (NO) donors including pretomanid (PMD) and explored the mechanisms of combination activity. The TB47 and PMD combination quickly abolished the LIGHT emission of luminescent bacilli, as was the case for the combination of TB47 and aurachin D, a putative cytochrome bd inhibitor. The TB47 and PMD combination inhibited M. tuberculosis oxygen consumption, decreased ATP levels, and had a delayed bactericidal effect. The NO scavenger carboxy-PTIO prevented the bactericidal activity of the drug combination, suggesting the requirement for NO. In addition, cytochrome bc1 inhibitors were largely bactericidal when administered with DETA NONOate, another NO donor. Proteomic analysis revealed that the cotreated bacilli had a compromised expression of the dormancy regulon proteins, PE/PPE proteins, and proteins required for the biosynthesis of several cofactors, including mycofactocin. Some of these proteomic changes, e.g., the impaired dormancy regulon induction, were attributed to PMD. In conclusion, combination of cytochrome bc1 inhibitors with PMD inhibited M. tuberculosis respiration and killed the bacilli. The activity of cytochrome bc1 inhibitors can be greatly enhanced by NO donors. Monitoring of luminescence may be further exploited to screen cytochrome bd inhibitors.

Keywords

LuxAB luciferase; Mycobacterium tuberculosis; cytochrome bc1 inhibitor; cytochrome bd oxidase; electron transport chain; luminescence; nitric oxide; pretomanid (PA-824).

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