Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2018 Jun 26;62(7):e02459-17.
doi: 10.1128/AAC.02459-17. Print 2018 Jul.

HC2091 Kills Mycobacterium tuberculosis by Targeting the MmpL3 Mycolic Acid Transporter

Huiqing Zheng  1 , John T Williams  1 , Garry B Coulson  1 , Elizabeth R Haiderer  1 , Robert B Abramovitch  2
Affiliations

HC2091 Kills Mycobacterium tuberculosis by Targeting the MmpL3 Mycolic Acid Transporter

Huiqing Zheng et al. Antimicrob Agents Chemother. .

Abstract

Tuberculosis, caused by the intracellular pathogen Mycobacterium tuberculosis, is a deadly disease that requires a long course of treatment. The emergence of drug-resistant strains has driven efforts to discover new small molecules that can kill the bacterium. Here, we report characterizations of the compound HC2091, which kills M. tuberculosis in a time- and dose-dependent manner in vitro and inhibits M. tuberculosis growth in macrophages. Whole-genome sequencing of spontaneous HC2091-resistant mutants identified single-nucleotide variants in the mmpL3 mycolic acid transporter gene. HC2091-resistant mutants do not exhibit cross-resistance with the well-characterized Mycobacterium membrane protein large 3 (MmpL3) inhibitor SQ109, suggesting a distinct mechanism of interaction with MmpL3. Additionally, HC2091 does not modulate bacterial membrane potential or kill nonreplicating M. tuberculosis, thus acting differently from other known MmpL3 inhibitors. RNA sequencing (RNA-seq) transcriptional profiling and lipid profiling of M. tuberculosis treated with HC2091 or SQ109 show that the two compounds target a similar pathway. HC2091 has a chemical structure dissimilar to those of previously described MmpL3 inhibitors, supporting the notion that HC2091 is a new class of MmpL3 inhibitor.

Keywords: MmpL3; Mycobacterium tuberculosis; cell envelope; drug discovery; high-throughput screen; resistant mutants.

PubMed Disclaimer

Figures

FIG 1
FIG 1
HC2091 is bactericidal to M. tuberculosis. (a) Chemical structure of HC2091. (b) HC2091 inhibits M. tuberculosis growth, with an EC50 of 6.4 μM. (c) HC2091 kills M. tuberculosis in a dose- and time-dependent manner. The error bars represent the standard deviation of the results from three technical replicates. The experiment was repeated twice with similar results.
FIG 2
FIG 2
HC2091 is active against intracellular M. tuberculosis and inactive against nonreplicating M. tuberculosis. (a) M. tuberculosis-infected murine bone marrow-derived macrophages were treated with doses of HC2091 ranging from 1 μM to 40 μM. CFU were enumerated on 7H10 agar plates at the indicated days postinfection. (b) The impact of HC2091 on nonreplicating M. tuberculosis was characterized using the hypoxic shift-down assay (30). SQ109 and INH were used as controls. Both experiments were repeated twice with similar results, and the error bars represent the standard deviation of the results from three technical replicates.
FIG 3
FIG 3
HC2091 inhibits TDM accumulation. (a) M. tuberculosis cells were treated with HC2091 or SQ109, and lipids were labeled with [14C]acetate for 6 days. Lipids were isolated and analyzed by TLC. (b) Quantification of TDM for M. tuberculosis cells treated with HC2091, SQ109, or DMSO control. Compared to the DMSO control, TDM is significantly reduced (P < 0.05), as determined by Student's t test. The error bars represent the standard deviation of the results from two biological replicates.
FIG 4
FIG 4
Shared transcriptional profiles between HC2091 and SQ109. Transcriptional profiling of M. tuberculosis cells treated with HC2091 (a) or SQ109 (b). Cells were treated with the compounds at a concentration of 10 μM for 24 h. The genes in red are significantly differentially regulated (q < 0.05). (c) Overlap exists between the HC2091 and SQ109 differentially expressed genes (downregulated >2×, q < 0.05). The heatmap represents the 11 commonly downregulated genes. CHP, conserved hypothetical protein; HP, hypothetical protein.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Hoagland DT, Liu J, Lee RB, Lee RE. 2016. New agents for the treatment of drug-resistant Mycobacterium tuberculosis. Adv Drug Deliv Rev 102:55–72. doi:10.1016/j.addr.2016.04.026. - DOI - PMC - PubMed
    1. Poce G, Consalvi S, Biava M. 2016. MmpL3 inhibitors: diverse chemical scaffolds inhibit the same target. Mini Rev Med Chem 16:1274–1283. doi:10.2174/1389557516666160118105319. - DOI - PubMed
    1. Belardinelli JM, Yazidi A, Yang L, Fabre L, Li W, Jacques B, Angala SK, Rouiller I, Zgurskaya HI, Sygusch J, Jackson M. 2016. Structure-function profile of MmpL3, the essential mycolic acid transporter from Mycobacterium tuberculosis. ACS Infect Dis 2:702–713. doi:10.1021/acsinfecdis.6b00095. - DOI - PMC - PubMed
    1. Xu Z, Meshcheryakov VA, Poce G, Chng SS. 2017. MmpL3 is the flippase for mycolic acids in mycobacteria. Proc Natl Acad Sci U S A 114:7993–7998. doi:10.1073/pnas.1700062114. - DOI - PMC - PubMed
    1. Tahlan K, Wilson R, Kastrinsky DB, Arora K, Nair V, Fischer E, Barnes SW, Walker JR, Alland D, Barry CE III, Boshoff HI. 2012. SQ109 targets MmpL3, a membrane transporter of trehalose monomycolate involved in mycolic acid donation to the cell wall core of Mycobacterium tuberculosis. Antimicrob Agents Chemother 56:1797–1809. doi:10.1128/AAC.05708-11. - DOI - PMC - PubMed

Publication types

MeSH terms