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The efflux pumps Rv1877 and Rv0191 play differential roles in the protection of Mycobacterium tuberculosis against chemical stress. Front Microbiol 2024; 15:1359188. [PMID: 38516013 PMCID: PMC10956863 DOI: 10.3389/fmicb.2024.1359188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Accepted: 02/12/2024] [Indexed: 03/23/2024] Open
Abstract
Background It was previously shown that GlnA3sc enabled Streptomyces coelicolor to survive in excess polyamines. However, subsequent studies revealed that Rv1878, the corresponding Mycobacterium tuberculosis (M.tb) ortholog, was not essential for the detoxification of spermine (Spm), in M.tb. On the other hand, the multi-drug efflux pump Rv1877 was previously shown to enable export of a wide range of compounds, while Rv0191 was shown to be more specific to chloramphenicol. Rationale Therefore, we first wanted to determine if detoxification of Spm by efflux can be achieved by any efflux pump, or if that was dependent upon the function of the pump. Next, since Rv1878 was found not to be essential for the detoxification of Spm, we sought to follow-up on the investigation of the physiological role of Rv1878 along with Rv1877 and Rv0191. Approach To evaluate the specificity of efflux pumps in the mycobacterial tolerance to Spm, we generated unmarked ∆rv1877 and ∆rv0191 M.tb mutants and evaluated their susceptibility to Spm. To follow up on the investigation of any other physiological roles they may have, we characterized them along with the ∆rv1878 M.tb mutant. Results The ∆rv1877 mutant was sensitive to Spm stress, while the ∆rv0191 mutant was not. On the other hand, the ∆rv1878 mutant grew better than the wild-type during iron starvation yet was sensitive to cell wall stress. The proteins Rv1877 and Rv1878 seemed to play physiological roles during hypoxia and acidic stress. Lastly, the ∆rv0191 mutant was the only mutant that was sensitive to oxidative stress. Conclusion The multidrug MFS-type efflux pump Rv1877 is required for Spm detoxification, as opposed to Rv0191 which seems to play a more specific role. Moreover, Rv1878 seems to play a role in the regulation of iron homeostasis and the reconstitution of the cell wall of M.tb. On the other hand, the sensitivity of the ∆rv0191 mutant to oxidative stress, suggests that Rv0191 may be responsible for the transport of low molecular weight thiols.
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Affiliation(s)
- Carine Sao Emani
- Microbial Interface Biology, Research Center Borstel, Leibniz Lung Center, Borstel, Germany
| | - Norbert Reiling
- Microbial Interface Biology, Research Center Borstel, Leibniz Lung Center, Borstel, Germany
- German Center for Infection Research (DZIF), Partner Site Hamburg-Lübeck-Borstel-Riems, Borstel, Germany
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2
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Spermine enhances the activity of anti-tuberculosis drugs. Microbiol Spectr 2024; 12:e0356823. [PMID: 38095461 PMCID: PMC10782994 DOI: 10.1128/spectrum.03568-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Accepted: 11/11/2023] [Indexed: 12/21/2023] Open
Abstract
IMPORTANCE This is the first study that attempted to demonstrate the mechanisms of reactive oxygen species (ROS) generation by spermine (Spm) in Mycobacterium tuberculosis (M.tb). Furthermore, this is the first study to demonstrate that it is able to enhance the activity of currently available and World Health Organization (WHO)-approved tuberculosis (TB) drugs. Spermine can easily be obtained since it is already found in our diet. Moreover, as opposed to conventional antibiotics, it is less toxic to humans since it is found in millimolar concentrations in the body. Finally, with the difficulty of curing TB with conventional antibiotics, this study suggests that less toxic molecules, such as Spm, could in a long-term perspective be incorporated in a TB regimen to boost the treatment.
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Affiliation(s)
- Carine Sao Emani
- Microbial Interface Biology, Research Center Borstel, Leibniz Lung Center, Borstel, Germany
| | - Norbert Reiling
- Microbial Interface Biology, Research Center Borstel, Leibniz Lung Center, Borstel, Germany
- German Center for Infection Research (DZIF), Partner Site Hamburg-Lübeck-Borstel-Riems, Borstel, Germany
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3
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Cysteine and resistance to oxidative stress: implications for virulence and antibiotic resistance. Trends Microbiol 2024; 32:93-104. [PMID: 37479622 DOI: 10.1016/j.tim.2023.06.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 06/28/2023] [Accepted: 06/30/2023] [Indexed: 07/23/2023]
Abstract
Reactive oxygen species (ROS), including the superoxide radical anion (O2•-), hydrogen peroxide (H2O2), and the hydroxyl radical (•HO), are inherent components of bacterial metabolism in an aerobic environment. Bacteria also encounter exogenous ROS, such as those produced by the host cells during the respiratory burst. As ROS have the capacity to damage bacterial DNA, proteins, and lipids, detoxification of ROS is critical for bacterial survival. It has been recently recognised that low-molecular-weight (LMW) thiols play a central role in this process. Here, we review the emerging role of cysteine in bacterial resistance to ROS with a link to broader elements of bacterial lifestyle closely associated with cysteine-mediated oxidative stress response, including virulence and antibiotic resistance.
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Affiliation(s)
- Alexandra Tikhomirova
- Monash University, Department of Microbiology, Infection and Immunity Program, Monash Biomedicine Discovery Institute, Melbourne, VIC 3800, Australia
| | - Mohammad M Rahman
- University of Kentucky, Department of Microbiology, Immunology and Molecular Genetics, Lexington, KY, USA
| | - Stephen P Kidd
- University of Adelaide, Department of Molecular and Biomedical Sciences, School of Biological Sciences, Adelaide, SA 5005, Australia; University of Adelaide, Research Centre for Infectious Disease (RCID) and Australian Centre for Antimicrobial Resistance Ecology (ACARE), Adelaide, SA 5005, Australia
| | - Richard L Ferrero
- Monash University, Department of Microbiology, Infection and Immunity Program, Monash Biomedicine Discovery Institute, Melbourne, VIC 3800, Australia; Hudson Institute of Medical Research, Centre for Innate Immunity and Infectious Diseases, Melbourne, VIC 3168, Australia; Monash University, Department of Molecular and Translational Science, Infection and Immunity Program, Monash Biomedicine Discovery Institute, Melbourne, VIC 3800, Australia
| | - Anna Roujeinikova
- Monash University, Department of Microbiology, Infection and Immunity Program, Monash Biomedicine Discovery Institute, Melbourne, VIC 3800, Australia; Monash University, Department of Biochemistry and Molecular Biology, Melbourne, VIC 3800, Australia.
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The ΔCysK 2 mutant of Mycobacterium tuberculosis is sensitive to vancomycin associated with changes in cell wall phospholipid profile. Biochem Biophys Res Commun 2022; 624:120-126. [PMID: 35940124 DOI: 10.1016/j.bbrc.2022.07.096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 07/11/2022] [Accepted: 07/25/2022] [Indexed: 11/26/2022]
Abstract
Cysteine plays a versatile role in cellular physiology and has previously been shown to be instrumental to Mycobacterium tuberculosis (M.tb) pathophysiology. In this study, we have generated mutants deficient in CysK2 and CysH, the key Cysteine, biosynthetic enzymes. In contrast to the ΔcysH mutant, the ΔcysK2 mutant is not an auxotroph and as such not essential for cysteine biosynthesis. Interestingly, the ΔcysK2 mutant shows increased sensitivity to cumene hydroperoxide, vitamin C, diamide, rifampicin and Vancomycin and shows alterations in phospholipid profile of Mtb cell wall. Our findings suggest that alteration in phospholipids content of M.tb cell wall by CysK2 may form a mode of defence against selected antibiotics and oxidative stress.
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Affiliation(s)
- Carine Sao Emani
- Division of Infectious Diseases, Department of Medicine/Department of Microbiology and Immunology, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada.
| | - Adrian Richter
- Martin-Luther-University of Halle-Wittenberg, Kurt-Mothes-Straße 3, 06120, Halle, Germany
| | - Albel Singh
- School of Biosciences and Institute of Microbiology and Infection, University of Birmingham, Birmingham, B15 2TT, UK
| | - Apoorva Bhatt
- School of Biosciences and Institute of Microbiology and Infection, University of Birmingham, Birmingham, B15 2TT, UK
| | - Yossef Av-Gay
- Division of Infectious Diseases, Department of Medicine/Department of Microbiology and Immunology, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada.
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New roles for glutathione: Modulators of bacterial virulence and pathogenesis. Redox Biol 2021; 44:102012. [PMID: 34090244 PMCID: PMC8182430 DOI: 10.1016/j.redox.2021.102012] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 04/29/2021] [Accepted: 05/12/2021] [Indexed: 01/02/2023] Open
Abstract
Low molecular weight (LMW) thiols contain reducing sulfhydryl groups that are important for maintaining antioxidant defense in the cell. Aside from the traditional roles of LMW thiols as redox regulators in bacteria, glutathione (GSH) has been reported to affect virulence and bacterial pathogenesis. The role of GSH in virulence is diverse, including the activation of virulence gene expression and contributing to optimal biofilm formation. GSH can also be converted to hydrogen sulfide (H2S) which is important for the pathogenesis of certain bacteria. Besides GSH, some bacteria produce other LMW thiols such as mycothiol and bacillithiol that affect bacterial virulence. We discuss these newer reported functions of LMW thiols modulating bacterial pathogenesis either directly or indirectly and via modulation of the host immune system.
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Affiliation(s)
- Joanne Wei Kay Ku
- Infectious Diseases Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Department of Biochemistry, National University of Singapore, 8 Medical Drive, 117596, Singapore
| | - Yunn-Hwen Gan
- Infectious Diseases Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Department of Biochemistry, National University of Singapore, 8 Medical Drive, 117596, Singapore.
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Osmium-arene complexes with high potency towards Mycobacterium tuberculosis. Metallomics 2021; 13:mfab007. [PMID: 33693931 PMCID: PMC8026400 DOI: 10.1093/mtomcs/mfab007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 02/08/2021] [Indexed: 02/04/2023]
Abstract
The treatment of tuberculosis (TB) poses a major challenge as frontline therapeutic agents become increasingly ineffective with the emergence and spread of drug-resistant strains of Mycobacterium tuberculosis (Mtb). To combat this global health problem, new antitubercular agents with novel modes of action are needed. We have screened a close family of 17 organometallic half-sandwich Os(II) complexes [(arene)Os(phenyl-azo/imino-pyridine)(Cl/I)]+Y- containing various arenes (p-cymene, biphenyl, or terphenyl), and NMe2, F, Cl, or Br phenyl or pyridyl substituents, for activity towards Mtb in comparison with normal human lung cells (MRC5). In general, complexes with a monodentate iodido ligand were more potent than chlorido complexes, and the five most potent iodido complexes (MIC 1.25-2.5 µM) have an electron-donating Me2N or OH substituent on the phenyl ring. As expected, the counter anion Y (PF6-, Cl-, I-) had little effect on the activity. The pattern of potency of the complexes towards Mtb is similar to that towards human cells, perhaps because in both cases intracellular thiols are likely to be involved in their activation and their redox mechanism of action. The most active complex against Mtb is the p-cymene Os(II) NMe2-phenyl-azopyridine iodido complex (2), a relatively inert complex that also exhibits potent activity towards cancer cells. The uptake of Os from complex 2 by Mtb is rapid and peaks after 6 h, with temperature-dependence studies suggesting a major role for active transport. Significance to Metallomics Antimicrobial resistance is a global health problem. New advances are urgently needed in the discovery of new antibiotics with novel mechanisms of action. Half-sandwich organometallic complexes offer a versatile platform for drug design. We show that with an appropriate choice of the arene, an N,N-chelated ligand, and monodentate ligand, half-sandwich organo-osmium(II) complexes can exhibit potent activity towards Mycobacterium tuberculosis (Mtb), the leading cause of death from a single infectious agent. The patterns of activity of the 17 azo- and imino-pyridine complexes studied here towards Mtb and normal lung cells suggest a common redox mechanism of action involving intracellular thiols.
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Affiliation(s)
| | - Collette S Guy
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK
| | | | - Russell J Needham
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, UK
| | - Elizabeth Fullam
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK
| | - Peter J Sadler
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, UK
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From infection niche to therapeutic target: the intracellular lifestyle of Mycobacterium tuberculosis. MICROBIOLOGY (READING, ENGLAND) 2021; 167:001041. [PMID: 33826491 PMCID: PMC8289223 DOI: 10.1099/mic.0.001041] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Accepted: 02/15/2021] [Indexed: 12/16/2022]
Abstract
Mycobacterium tuberculosis (Mtb) is an obligate human pathogen killing millions of people annually. Treatment for tuberculosis is lengthy and complicated, involving multiple drugs and often resulting in serious side effects and non-compliance. Mtb has developed numerous complex mechanisms enabling it to not only survive but replicate inside professional phagocytes. These mechanisms include, among others, overcoming the phagosome maturation process, inhibiting the acidification of the phagosome and inhibiting apoptosis. Within the past decade, technologies have been developed that enable a more accurate understanding of Mtb physiology within its intracellular niche, paving the way for more clinically relevant drug-development programmes. Here we review the molecular biology of Mtb pathogenesis offering a unique perspective on the use and development of therapies that target Mtb during its intracellular life stage.
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Affiliation(s)
| | - Tirosh Shapira
- Division of Infectious Disease, Department of Medicine, The University of British Columbia, Vancouver, Canada
| | - Carine Sao Emani
- Division of Infectious Disease, Department of Medicine, The University of British Columbia, Vancouver, Canada
| | - Yossef Av-Gay
- Department of Microbiology & Immunology, The University of British Columbia, Vancouver, Canada
- Division of Infectious Disease, Department of Medicine, The University of British Columbia, Vancouver, Canada
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Preliminary Characterization of a Ni2+-Activated and Mycothiol-Dependent Glyoxalase I Enzyme from Streptomyces coelicolor. INORGANICS 2019. [DOI: 10.3390/inorganics7080099] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The glyoxalase system consists of two enzymes, glyoxalase I (Glo1) and glyoxalase II (Glo2), and converts a hemithioacetal substrate formed between a cytotoxic alpha-ketoaldehyde, such as methylglyoxal (MG), and an intracellular thiol, such as glutathione, to a non-toxic alpha-hydroxy acid, such as d-lactate, and the regenerated thiol. Two classes of Glo1 have been identified. The first is a Zn2+-activated class and is exemplified by the Homo sapiens Glo1. The second class is a Ni2+-activated enzyme and is exemplified by the Escherichia coli Glo1. Glutathione is the intracellular thiol employed by Glo1 from both these sources. However, many organisms employ other intracellular thiols. These include trypanothione, bacillithiol, and mycothiol. The trypanothione-dependent Glo1 from Leishmania major has been shown to be Ni2+-activated. Genetic studies on Bacillus subtilis and Corynebacterium glutamicum focused on MG resistance have indicated the likely existence of Glo1 enzymes employing bacillithiol or mycothiol respectively, although no protein characterizations have been reported. The current investigation provides a preliminary characterization of an isolated mycothiol-dependent Glo1 from Streptomyces coelicolor. The enzyme has been determined to display a Ni2+-activation profile and indicates that Ni2+-activated Glo1 are indeed widespread in nature regardless of the intracellular thiol employed by an organism.
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The role of low molecular weight thiols in Mycobacterium tuberculosis. Tuberculosis (Edinb) 2019; 116:44-55. [PMID: 31153518 DOI: 10.1016/j.tube.2019.04.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 04/16/2019] [Accepted: 04/22/2019] [Indexed: 02/06/2023]
Abstract
Low molecular weight (LMW) thiols are molecules with a functional sulfhydryl group that enable them to detoxify reactive oxygen species, reactive nitrogen species and other free radicals. Their roles range from their ability to modulate the immune system to their ability to prevent damage of biological molecules such as DNA and proteins by protecting against oxidative, nitrosative and acidic stress. LMW thiols are synthesized and found in both eukaryotes and prokaryotes. Due to their beneficial role to both eukaryotes and prokaryotes, their specific functions need to be elucidated, most especially in pathogenic prokaryotes such as Mycobacterium tuberculosis (M.tb), in order to provide a rationale for targeting their biosynthesis for drug development. Ergothioneine (ERG), mycothiol (MSH) and gamma-glutamylcysteine (GGC) are LMW thiols that have been shown to interplay to protect M.tb against cellular stress. Though ERG, MSH and GGC seem to have overlapping functions, studies are gradually revealing their unique physiological roles. Understanding their unique physiological role during the course of tuberculosis (TB) infection, would pave the way for the development of drugs that target their biosynthetic pathway. This review identifies the knowledge gap in the unique physiological roles of LMW thiols and proposes their mechanistic roles based on previous studies. In addition, it gives an update on identified inhibitors of their biosynthetic enzymes.
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