1
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Niet SVD, Green KD, Schimmel IM, Bakker JD, Lodder B, Reits EA, Garneau-Tsodikova S, van der Wel NN. Zafirlukast induces DNA condensation and has bactericidal effect on replicating Mycobacterium abscessus. Antimicrob Agents Chemother 2024:e0002924. [PMID: 38990015 DOI: 10.1128/aac.00029-24] [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: 01/05/2024] [Accepted: 06/09/2024] [Indexed: 07/12/2024] Open
Abstract
Mycobacterium abscessus infections are emerging in cystic fibrosis patients, and treatment success rate in these patients is only 33% due to extreme antibiotic resistance. Thus, new treatment options are essential. An interesting target could be Lsr2, a nucleoid-associated protein involved in mycobacterial virulence. Zafirlukast is a Food and Drug Administration (FDA)-approved drug against asthma that was shown to bind Lsr2. In this study, zafirlukast treatment is shown to reduce M. abscessus growth, with a minimal inhibitory concentration of 16 µM and a bactericidal concentration of 64 µM in replicating bacteria only. As an initial response, DNA condensation, a known stress response of mycobacteria, occurs after 1 h of treatment with zafirlukast. During continued zafirlukast treatment, the morphology of the bacteria alters and the structural integrity of the bacteria is lost. After 4 days of treatment, reduced viability is measured in different culture media, and growth of M. abscessus is reduced in a dose-dependent manner. Using transmission electron microscopy, we demonstrated that the hydrophobic multilayered cell wall and periplasm are disorganized and ribosomes are reduced in size and relocalized. In summary, our data demonstrate that zafirlukast alters the morphology of M. abscessus and is bactericidal at 64 µM. The bactericidal concentration of zafirlukast is relatively high, and it is only effective on replicating bacteria but as zafirlukast is an FDA-approved drug, and currently used as an anti-asthma treatment, it could be an interesting drug to further study in in vivo experiments to determine whether it could be used as an antibiotic for M. abscessus infections.
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Affiliation(s)
- Sanne van der Niet
- Electron Microscopy Centre Amsterdam, Amsterdam University Medical Centre, Amsterdam, the Netherlands
| | - Keith D Green
- College of Pharmacy, University of Kentucky, Lexington, Kentucky, USA
| | - Irene M Schimmel
- Electron Microscopy Centre Amsterdam, Amsterdam University Medical Centre, Amsterdam, the Netherlands
| | - Jordy de Bakker
- Electron Microscopy Centre Amsterdam, Amsterdam University Medical Centre, Amsterdam, the Netherlands
| | - Bastiaan Lodder
- Electron Microscopy Centre Amsterdam, Amsterdam University Medical Centre, Amsterdam, the Netherlands
| | - Eric A Reits
- Electron Microscopy Centre Amsterdam, Amsterdam University Medical Centre, Amsterdam, the Netherlands
| | | | - Nicole N van der Wel
- Electron Microscopy Centre Amsterdam, Amsterdam University Medical Centre, Amsterdam, the Netherlands
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2
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Johansen MD, Spaink HP, Oehlers SH, Kremer L. Modeling nontuberculous mycobacterial infections in zebrafish. Trends Microbiol 2024; 32:663-677. [PMID: 38135617 DOI: 10.1016/j.tim.2023.11.011] [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: 10/24/2023] [Revised: 11/24/2023] [Accepted: 11/27/2023] [Indexed: 12/24/2023]
Abstract
The incidence of infections due to nontuberculous mycobacteria (NTM) has increased rapidly in recent years, surpassing tuberculosis in developed countries. Due to inherent antimicrobial resistance, NTM infections are particularly difficult to treat with low cure rates. There is an urgent need to understand NTM pathogenesis and to develop novel therapeutic approaches for the treatment of NTM diseases. Zebrafish have emerged as an excellent animal model due to genetic amenability and optical transparency during embryonic development, allowing spatiotemporal visualization of host-pathogen interactions. Furthermore, adult zebrafish possess fully functional innate and adaptive immunity and recapitulate important pathophysiological hallmarks of mycobacterial infection. Here, we report recent breakthroughs in understanding the hallmarks of NTM infections using the zebrafish model.
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Affiliation(s)
- Matt D Johansen
- Centre for Inflammation, Centenary Institute and University of Technology Sydney, Faculty of Science, School of Life Sciences, Sydney, NSW, Australia
| | - Herman P Spaink
- Institute of Biology, Leiden University, Leiden, The Netherlands
| | - Stefan H Oehlers
- A*STAR Infectious Diseases Labs (A*STAR ID Labs), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Laurent Kremer
- Centre National de la Recherche Scientifique, UMR 9004, Institut de Recherche en Infectiologie de Montpellier (IRIM), Université de Montpellier, 1919 Route de Mende, 34293, Montpellier, France; INSERM, IRIM, 34293 Montpellier, France.
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3
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Santoshi M, Tare P, Nagaraja V. Nucleoid-associated proteins of mycobacteria come with a distinctive flavor. Mol Microbiol 2024. [PMID: 38922783 DOI: 10.1111/mmi.15287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Revised: 05/31/2024] [Accepted: 06/05/2024] [Indexed: 06/28/2024]
Abstract
In every bacterium, nucleoid-associated proteins (NAPs) play crucial roles in chromosome organization, replication, repair, gene expression, and other DNA transactions. Their central role in controlling the chromatin dynamics and transcription has been well-appreciated in several well-studied organisms. Here, we review the diversity, distribution, structure, and function of NAPs from the genus Mycobacterium. We highlight the progress made in our understanding of the effects of these proteins on various processes and in responding to environmental stimuli and stress of mycobacteria in their free-living as well as during distinctive intracellular lifestyles. We project them as potential drug targets and discuss future studies to bridge the information gap with NAPs from well-studied systems.
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Affiliation(s)
- Meghna Santoshi
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru, India
| | - Priyanka Tare
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru, India
| | - Valakunja Nagaraja
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru, India
- Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru, India
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4
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Lagune M, Kremer L, Herrmann JL. Mycobacterium abscessus, a complex of three fast-growing subspecies sharing virulence traits with slow-growing mycobacteria. Clin Microbiol Infect 2024; 30:726-731. [PMID: 37797823 DOI: 10.1016/j.cmi.2023.08.036] [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: 05/15/2023] [Revised: 08/28/2023] [Accepted: 08/31/2023] [Indexed: 10/07/2023]
Abstract
BACKGROUND Mycobacterium abscessus belongs to the largest group of mycobacteria, the rapid-growing saprophytic mycobacteria, and is one of the most difficult-to-treat opportunistic pathogen. Several features pertain to the high adaptability of M. abscessus to the host. These include the capacity to survive and persist within amoebae, to transition from a smooth to a rough morphotype that occurs during the course of the disease and to express of a wide array of virulence factors. OBJECTIVES The main objective of this narrative review consists to report major assets of M. abscessus that contribute to the virulence of these rapid-growing saprophytic mycobacteria. Strikingly, many of these determinants, whether they are from a mycobacterial origin or acquired by horizontal gene transfer, are known virulence factors found in slow-growing and strict pathogens for humans and animals. SOURCES In the light of recent published work in the field we attempted to highlight major features characterizing M. abscessus pathogenicity and to explain why this led to the emergence of this mycobacterial species in patients with cystic fibrosis. CONTENT M. abscessus genome plasticity, the smooth-to-rough transition, and the expression of a panel of enzymes associated with virulence in other bacteria are key players in M. abscessus virulence. In addition, the very large repertoire of lipid transporters, known as mycobacterial membrane protein large and small (MmpL and MmpS respectively), deeply influences the pathogenicity of M. abscessus, as exemplified here for some of them. IMPLICATIONS All these traits largely contribute to make M. abscessus a unique mycobacterium regarding to its pathophysiological processes, ranging from the early colonization steps to the establishment of severe and chronic pulmonary diseases.
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Affiliation(s)
- Marion Lagune
- Department of Pathology and Immunology, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Laurent Kremer
- Centre National de la Recherche Scientifique UMR 9004, Institut de Recherche en Infectiologie de Montpellier (IRIM), Université de Montpellier, Montpellier, France; INSERM, IRIM, Montpellier, France
| | - Jean-Louis Herrmann
- Université Paris-Saclay, UVSQ, INSERM, U1173 Infection et Inflammation, Montigny-le-Bretonneux, France; Assistance Publique-Hôpitaux de Paris, Hôpitaux Universitaires Ile-de-France Ouest, GHU Paris-Saclay, Hôpital Raymond Poincaré, Garches, France.
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5
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Ng WL, Rego EH. A nucleoid-associated protein is involved in the emergence of antibiotic resistance by promoting the frequent exchange of the replicative DNA polymerase in Mycobacterium smegmatis. mSphere 2024; 9:e0012224. [PMID: 38591887 PMCID: PMC11237743 DOI: 10.1128/msphere.00122-24] [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: 03/04/2024] [Accepted: 03/16/2024] [Indexed: 04/10/2024] Open
Abstract
Antibiotic resistance in Mycobacterium tuberculosis exclusively originates from chromosomal mutations, either during normal DNA replication or under stress, when the expression of error-prone DNA polymerases increases to repair damaged DNA. To bypass DNA lesions and catalyze error-prone DNA synthesis, translesion polymerases must be able to access the DNA, temporarily replacing the high-fidelity replicative polymerase. The mechanisms that govern polymerase exchange are not well understood, especially in mycobacteria. Here, using a suite of quantitative fluorescence imaging techniques, we discover that in Mycobacterium smegmatis, as in other bacterial species, the replicative polymerase, DnaE1, exchanges at a timescale much faster than that of DNA replication. Interestingly, this fast exchange rate depends on an actinobacteria-specific nucleoid-associated protein (NAP), Lsr2. In cells missing lsr2, DnaE1 exchanges less frequently, and the chromosome is replicated more faithfully. Additionally, in conditions that damage DNA, cells lacking lsr2 load the complex needed to bypass DNA lesions less effectively and, consistently, replicate with higher fidelity but exhibit growth defects. Together, our results show that Lsr2 promotes dynamic flexibility of the mycobacterial replisome, which is critical for robust cell growth and lesion repair in conditions that damage DNA. IMPORTANCE Unlike many other pathogens, Mycobacterium tuberculosis has limited ability for horizontal gene transfer, a major mechanism for developing antibiotic resistance. Thus, the mechanisms that facilitate chromosomal mutagenesis are of particular importance in mycobacteria. Here, we show that Lsr2, a nucleoid-associated protein, has a novel role in DNA replication and mutagenesis in the model mycobacterium Mycobacterium smegmatis. We find that Lsr2 promotes the fast exchange rate of the replicative DNA polymerase, DnaE1, at the replication fork and is important for the effective loading of the DnaE2-ImuA'-ImuB translesion complex. Without lsr2, M. smegmatis replicates its chromosome more faithfully and acquires resistance to rifampin at a lower rate, but at the cost of impaired survival to DNA damaging agents. Together, our work establishes Lsr2 as a potential factor in the emergence of mycobacterial antibiotic resistance.
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Affiliation(s)
- Wei L Ng
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut, USA
| | - E Hesper Rego
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut, USA
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6
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Andima M, Boese A, Paul P, Koch M, Loretz B, Lehr CM. Targeting Intracellular Bacteria with Dual Drug-loaded Lactoferrin Nanoparticles. ACS Infect Dis 2024; 10:1696-1710. [PMID: 38577780 PMCID: PMC11091908 DOI: 10.1021/acsinfecdis.4c00045] [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: 01/16/2024] [Revised: 03/18/2024] [Accepted: 03/26/2024] [Indexed: 04/06/2024]
Abstract
Treatment of microbial infections is becoming daunting because of widespread antimicrobial resistance. The treatment challenge is further exacerbated by the fact that certain infectious bacteria invade and localize within host cells, protecting the bacteria from antimicrobial treatments and the host's immune response. To survive in the intracellular niche, such bacteria deploy surface receptors similar to host cell receptors to sequester iron, an essential nutrient for their virulence, from host iron-binding proteins, in particular lactoferrin and transferrin. In this context, we aimed to target lactoferrin receptors expressed by macrophages and bacteria; as such, we prepared and characterized lactoferrin nanoparticles (Lf-NPs) loaded with a dual drug combination of antimicrobial natural alkaloids, berberine or sanguinarine, with vancomycin or imipenem. We observed increased uptake of drug-loaded Lf-NPs by differentiated THP-1 cells with up to 90% proportion of fluorescent cells, which decreased to about 60% in the presence of free lactoferrin, demonstrating the targeting ability of Lf-NPs. The encapsulated antibiotic drug cocktail efficiently cleared intracellular Staphylococcus aureus (Newman strain) compared to the free drug combinations. However, the encapsulated drugs and the free drugs alike exhibited a bacteriostatic effect against the hard-to-treat Mycobacterium abscessus (smooth variant). In conclusion, the results of this study demonstrate the potential of lactoferrin nanoparticles for the targeted delivery of antibiotic drug cocktails for the treatment of intracellular bacteria.
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Affiliation(s)
- Moses Andima
- Department
of Drug Delivery (DDEL), Helmholtz Institute
for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for
Infection Research, Campus E8.1, Saarbrücken 66123, Germany
- Department
of Chemistry, Faculty of Science and Education, Busitema University, P.O Box 236, Tororo 21435, Uganda
| | - Annette Boese
- Department
of Drug Delivery (DDEL), Helmholtz Institute
for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for
Infection Research, Campus E8.1, Saarbrücken 66123, Germany
| | - Pascal Paul
- Department
of Drug Delivery (DDEL), Helmholtz Institute
for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for
Infection Research, Campus E8.1, Saarbrücken 66123, Germany
| | - Marcus Koch
- INM-Leibniz
Institute for New Materials, Campus D2 2, Saarbrücken 66123, Germany
| | - Brigitta Loretz
- Department
of Drug Delivery (DDEL), Helmholtz Institute
for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for
Infection Research, Campus E8.1, Saarbrücken 66123, Germany
| | - Claus-Micheal Lehr
- Department
of Drug Delivery (DDEL), Helmholtz Institute
for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for
Infection Research, Campus E8.1, Saarbrücken 66123, Germany
- Department
of Pharmacy, Saarland University, Saarbrücken 66123, Germany
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7
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Gerges E, Rodríguez-Ordoñez MDP, Durand N, Herrmann JL, Crémazy F. Lsr2, a pleiotropic regulator at the core of the infectious strategy of Mycobacterium abscessus. Microbiol Spectr 2024; 12:e0352823. [PMID: 38353553 PMCID: PMC10913753 DOI: 10.1128/spectrum.03528-23] [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: 09/30/2023] [Accepted: 01/22/2024] [Indexed: 03/06/2024] Open
Abstract
Mycobacterium abscessus is a non-tuberculous mycobacterium, causing lung infections in cystic fibrosis patients. During pulmonary infection, M. abscessus switches from smooth (Mabs-S) to rough (Mabs-R) morphotypes, the latter being hyper-virulent. Previously, we isolated the lsr2 gene as differentially expressed during S-to-R transition. lsr2 encodes a pleiotropic transcription factor that falls under the superfamily of nucleoid-associated proteins. Here, we used two functional genomic methods, RNA-seq and chromatin immunoprecipitation-sequencing (ChIP-seq), to elucidate the molecular role of Lsr2 in the pathobiology of M. abscessus. Transcriptomic analysis shows that Lsr2 differentially regulates gene expression across both morphotypes, most of which are involved in several key cellular processes of M. abscessus, including host adaptation and antibiotic resistance. These results were confirmed through quantitative real-time PCR, as well as by minimum inhibitory concentration tests and infection tests on macrophages in the presence of antibiotics. ChIP-seq analysis revealed that Lsr2 extensively binds the M. abscessus genome at AT-rich sequences and appears to form long domains that participate in the repression of its target genes. Unexpectedly, the genomic distribution of Lsr2 revealed no distinctions between Mabs-S and Mabs-R, implying more intricate mechanisms at play for achieving target selectivity.IMPORTANCELsr2 is a crucial transcription factor and chromosome organizer involved in intracellular growth and virulence in the smooth and rough morphotypes of Mycobacterium abscessus. Using RNA-seq and chromatin immunoprecipitation-sequencing (ChIP-seq), we investigated the molecular role of Lsr2 in gene expression regulation along with its distribution on M. abscessus genome. Our study demonstrates the pleiotropic regulatory role of Lsr2, regulating the expression of many genes coordinating essential cellular and molecular processes in both morphotypes. In addition, we have elucidated the role of Lsr2 in antibiotic resistance both in vitro and in vivo, where lsr2 mutant strains display heightened sensitivity to antibiotics. Through ChIP-seq, we reported the widespread distribution of Lsr2 on M. abscessus genome, revealing a direct repressive effect due to its extensive binding on promoters or coding sequences of its targets. This study unveils the significant regulatory role of Lsr2, intricately intertwined with its function in shaping the organization of the M. abscessus genome.
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Affiliation(s)
- Elias Gerges
- Université Paris-Saclay, UVSQ, Inserm, Infection et inflammation, Montigny-Le-Bretonneux, France
| | - María del Pilar Rodríguez-Ordoñez
- Université Paris-Saclay, Université d’Evry, Laboratoire Européen de Recherche pour la Polyarthrite rhumatoïde-Genhotel, Evry, France
| | - Nicolas Durand
- Université Paris-Saclay, UVSQ, Inserm, Infection et inflammation, Montigny-Le-Bretonneux, France
| | - Jean-Louis Herrmann
- Université Paris-Saclay, UVSQ, Inserm, Infection et inflammation, Montigny-Le-Bretonneux, France
- APHP, GHU Paris-Saclay, Hôpital Raymond Poincaré, Service de Microbiologie, Garches, France
| | - Frédéric Crémazy
- Université Paris-Saclay, UVSQ, Inserm, Infection et inflammation, Montigny-Le-Bretonneux, France
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8
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Gerges E, Herrmann JL, Crémazy F. [Lsr2: A Nucleoid Associated Protein (NAP) and a transcription factor in mycobacteria]. Med Sci (Paris) 2024; 40:154-160. [PMID: 38411423 DOI: 10.1051/medsci/2023218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/28/2024] Open
Abstract
Lsr2, a small protein mainly found in actinobacteria, plays a crucial role in the virulence and adaptation of mycobacteria to environmental conditions. As a member of the nucleoid-associated protein (NAPs) superfamily, Lsr2 influences DNA organization by facilitating the formation of chromosomal loops in vitro and, therefore, may be a major player in the three-dimensional folding of the genome. Additionally, Lsr2 also acts as a transcription factor, regulating the expression of numerous genes responsible for coordinating a myriad of cellular and molecular processes essential for the actinobacteria. Similar to the H-NS protein, its ortholog in enterobacteria, its role in transcriptional repression likely relies on oligomerization, rigidifying, and bridging of DNA, thereby disrupting RNA polymerase recruitment as well as the elongation of RNA transcripts.
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Affiliation(s)
- Elias Gerges
- Université Paris-Saclay, UVSQ, Inserm, Infection et inflammation, 78180 Montigny-Le-Bretonneux, France
| | - Jean-Louis Herrmann
- Université Paris-Saclay, UVSQ, Inserm, Infection et inflammation, 78180 Montigny-Le-Bretonneux, France
| | - Frédéric Crémazy
- Université Paris-Saclay, UVSQ, Inserm, Infection et inflammation, 78180 Montigny-Le-Bretonneux, France
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9
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Ng WL, Rego EH. A nucleoid-associated protein is involved in the emergence of antibiotic resistance by promoting the frequent exchange of the replicative DNA polymerase in M. smegmatis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.06.12.544663. [PMID: 38260554 PMCID: PMC10802252 DOI: 10.1101/2023.06.12.544663] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Antibiotic resistance in M. tuberculosis exclusively originates from chromosomal mutations, either during normal DNA replication or under stress, when the expression of error-prone DNA polymerases increases to repair damaged DNA. To bypass DNA lesions and catalyze error-prone DNA synthesis, translesion polymerases must be able to access the DNA, temporarily replacing the high-fidelity replicative polymerase. The mechanisms that govern polymerase exchange are not well understood, especially in mycobacteria. Here, using a suite of quantitative fluorescence imaging techniques, we discover that, as in other bacterial species, in M. smegmatis, the replicative polymerase, DnaE1, exchanges at a timescale much faster than that of DNA replication. Interestingly, this fast exchange rate depends on an actinobacteria-specific nucleoid-associated protein (NAP), Lsr2. In cells missing lsr2, DnaE1 exchanges less frequently, and the chromosome is replicated more faithfully. Additionally, in conditions that damage DNA, cells lacking lsr2 load the complex needed to bypass DNA lesions less effectively and, consistently, replicate with higher fidelity but exhibit growth defects. Together, our results show that Lsr2 promotes dynamic flexibility of the mycobacterial replisome, which is critical for robust cell growth and lesion repair in conditions that damage DNA.
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Affiliation(s)
- Wei L. Ng
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, 06519
| | - E. Hesper Rego
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, 06519
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10
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Born SEM, Reichlen MJ, Bartek IL, Benoit JB, Frank DN, Voskuil MI. Population heterogeneity in Mycobacterium smegmatis and Mycobacterium abscessus. MICROBIOLOGY (READING, ENGLAND) 2023; 169:001402. [PMID: 37862100 PMCID: PMC10634367 DOI: 10.1099/mic.0.001402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Accepted: 10/06/2023] [Indexed: 10/21/2023]
Abstract
Bacteria use population heterogeneity, the presence of more than one phenotypic variant in a clonal population, to endure diverse environmental challenges - a 'bet-hedging' strategy. Phenotypic variants have been described in many bacteria, but the phenomenon is not well-understood in mycobacteria, including the environmental factors that influence heterogeneity. Here, we describe three reproducible morphological variants in M. smegmatis - smooth, rough, and an intermediate morphotype that predominated under typical laboratory conditions. M. abscessus has two recognized morphotypes, smooth and rough. Interestingly, M. tuberculosis exists in only a rough form. The shift from smooth to rough in both M. smegmatis and M. abscessus was observed over time in extended static culture, however the frequency of the rough morphotype was high in pellicle preparations compared to planktonic culture, suggesting a role for an aggregated microenvironment in the shift to the rough form. Differences in growth rate, biofilm formation, cell wall composition, and drug tolerance were noted among M. smegmatis and M. abscessus variants. Deletion of the global regulator lsr2 shifted the M. smegmatis intermediate morphotype to a smooth form but did not fully phenocopy the naturally generated smooth morphotype, indicating Lsr2 is likely downstream of the initiating regulatory cascade that controls these morphotypes. Rough forms typically correlate with higher invasiveness and worse outcomes during infection and our findings indicate the shift to this rough form is promoted by aggregation. Our findings suggest that mycobacterial population heterogeneity, reflected in colony morphotypes, is a reproducible, programmed phenomenon that plays a role in adaptation to unique environments and this heterogeneity may influence infection progression and response to treatment.
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Affiliation(s)
- Sarah E. M. Born
- Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Matthew J. Reichlen
- Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Iona L. Bartek
- Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Jeanne B. Benoit
- Division of Infectious Diseases, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Daniel N. Frank
- Division of Infectious Diseases, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Martin I. Voskuil
- Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
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11
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Pereira MMR, de Oliveira FM, da Costa AC, Junqueira-Kipnis AP, Kipnis A. Ferritin from Mycobacterium abscessus is involved in resistance to antibiotics and oxidative stress. Appl Microbiol Biotechnol 2023; 107:2577-2595. [PMID: 36862179 DOI: 10.1007/s00253-023-12420-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 01/22/2023] [Accepted: 01/30/2023] [Indexed: 03/03/2023]
Abstract
Mycobacterium abscessus subsp. massiliense (Mycma) is a rapidly growing Mycobacterium belonging to the M. abscessus complex that is often associated with lung and soft tissue infection outbreaks. Mycma is resistant to many antimicrobials, including those used for treating tuberculosis. Therefore, Mycma infections are difficult to treat and may lead to high infectious complication rates. Iron is essential for bacterial growth and establishment of infection. During infection, the host reduces iron concentrations as a defense mechanism. To counteract the host-induced iron deficiency, Mycma produces siderophores to capture iron. Mycma has two ferritins (encoded by mycma_0076 and mycma_0077) modulated by different iron concentrations, which allow the survival of this pathogen during iron scarcity. In this study, we constructed knockout (Mycma 0076KO) and complemented (Mycma 0076KOc) gene strains for mycma_0076 to understand the function of 0076 ferritin. Deletion of mycma_0076 in Mycma led to the transition in colony morphology from smooth to rough, alteration of the glycopeptidolipids spectra, increased permeability of the envelope, reduction in biofilm formation, increased susceptibility to antimicrobials and hydrogen peroxide-induced oxidative stress, and decreased internalization by macrophages. This study shows that Mycma_0076 ferritin in Mycma is involved in resistance to oxidative stress and antimicrobials, and alteration of cell envelope architecture. KEY POINTS: • Deletion of the mycma_0076 gene altered colony morphology to rough; • Mycma 0076KO changed GPL profile; • Absence of Mycma_0076 ferritin results in increased susceptibility to antimicrobials and oxidative stress in Mycma. Legend: a In wild-type M. abscessus subsp. massiliense strain, iron is captured from the environment by carboxymycobactins and mycobactins (1). Iron-dependent regulator (IdeR) proteins bind to ferrous iron (Fe+2) in the bacterial cytoplasm leading to the activation of the IdeR-Fe+2 complex (2). The activated complex binds to the promoter regions of iron-dependent genes, called iron box, which in turn help in the recruitment of RNA polymerase to promote transcription of genes such as mycma_0076 and mycma_0077 ferritin genes (3). Mycma_0076 and Mycma_0077 ferritins bind to excess iron in the medium and promote Fe2+ oxidation into ferric iron (Fe3+) and store iron molecules to be released under iron scarcity conditions. (4) Genes related to biosynthesis and transport of glycopeptidolipids (GPL) are expressed normally and the cell envelope is composed of different GPL species (colored squares represented on the cell surface (GPLs). Consequently, WT Mycma present smooth colony phenotype (5). b In Mycma 0076KO strain, the lack of ferritin 0076 causes overexpression of mycma_0077 (6), but does not restore wild-type iron homeostasis and thus may result in free intracellular iron, even in the presence of miniferritins (MaDps). The excess iron potentiates oxidative stress (7) by generating hydroxyl radicals through Fenton Reaction. During this process, through an unknown mechanism, that could involve Lsr2 (8), the expression of GPL synthesis locus is regulated positively and/or negatively, resulting in alteration of GPL composition in the membrane (as represented by different colors of squares on the cell surface), resulting in a rough colony phenotype (9). The changes of GPL can increase cell wall permeability, contributing to antimicrobial susceptibility (10).
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Affiliation(s)
- Maria Micaella Rodrigues Pereira
- Institute of Tropical Pathology and Public Health, Federal University of Goiás, Goiânia, GO, Brazil
- Tropical Medicine and Public Health Graduate Program at Federal, University of Goiás, Goiânia, GO, Brazil
| | - Fábio Muniz de Oliveira
- Institute of Tropical Pathology and Public Health, Federal University of Goiás, Goiânia, GO, Brazil
- Tropical Medicine and Public Health Graduate Program at Federal, University of Goiás, Goiânia, GO, Brazil
- Indiana Center for Regenerative Medicine and Engineering, School of Medicine, Indiana University, Indianapolis, IN, USA
| | | | | | - André Kipnis
- Institute of Tropical Pathology and Public Health, Federal University of Goiás, Goiânia, GO, Brazil.
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12
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Dulberger CL, Guerrero-Bustamante CA, Owen SV, Wilson S, Wuo MG, Garlena RA, Serpa LA, Russell DA, Zhu J, Braunecker BJ, Squyres GR, Baym M, Kiessling LL, Garner EC, Rubin EJ, Hatfull GF. Mycobacterial nucleoid-associated protein Lsr2 is required for productive mycobacteriophage infection. Nat Microbiol 2023; 8:695-710. [PMID: 36823286 PMCID: PMC10066036 DOI: 10.1038/s41564-023-01333-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 01/23/2023] [Indexed: 02/25/2023]
Abstract
Mycobacteriophages are a diverse group of viruses infecting Mycobacterium with substantial therapeutic potential. However, as this potential becomes realized, the molecular details of phage infection and mechanisms of resistance remain ill-defined. Here we use live-cell fluorescence microscopy to visualize the spatiotemporal dynamics of mycobacteriophage infection in single cells and populations, showing that infection is dependent on the host nucleoid-associated Lsr2 protein. Mycobacteriophages preferentially adsorb at Mycobacterium smegmatis sites of new cell wall synthesis and following DNA injection, Lsr2 reorganizes away from host replication foci to establish zones of phage DNA replication (ZOPR). Cells lacking Lsr2 proceed through to cell lysis when infected but fail to generate consecutive phage bursts that trigger epidemic spread of phage particles to neighbouring cells. Many mycobacteriophages code for their own Lsr2-related proteins, and although their roles are unknown, they do not rescue the loss of host Lsr2.
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Affiliation(s)
- Charles L Dulberger
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, MA, USA.,Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA
| | | | - Siân V Owen
- Department of Biomedical Informatics and Laboratory of Systems Pharmacology, Harvard Medical School, Boston, MA, USA
| | - Sean Wilson
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA
| | - Michael G Wuo
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Rebecca A Garlena
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, USA
| | - Lexi A Serpa
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, USA
| | - Daniel A Russell
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, USA
| | - Junhao Zhu
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, MA, USA
| | - Ben J Braunecker
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, MA, USA
| | - Georgia R Squyres
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA
| | - Michael Baym
- Department of Biomedical Informatics and Laboratory of Systems Pharmacology, Harvard Medical School, Boston, MA, USA
| | - Laura L Kiessling
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Ethan C Garner
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA
| | - Eric J Rubin
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, MA, USA.
| | - Graham F Hatfull
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, USA.
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13
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Updated Review on the Mechanisms of Pathogenicity in Mycobacterium abscessus, a Rapidly Growing Emerging Pathogen. Microorganisms 2022; 11:microorganisms11010090. [PMID: 36677382 PMCID: PMC9866562 DOI: 10.3390/microorganisms11010090] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 12/21/2022] [Accepted: 12/23/2022] [Indexed: 01/01/2023] Open
Abstract
In recent years, Mycobacterium abscessus has appeared as an emerging pathogen, with an increasing number of disease cases reported worldwide that mainly occur among patients with chronic lung diseases or impaired immune systems. The treatment of this pathogen represents a challenge due to the multi-drug-resistant nature of this species and its ability to evade most therapeutic approaches. However, although predisposing host factors for disease are well known, intrinsic pathogenicity mechanisms of this mycobacterium are still not elucidated. Like other mycobacteria, intracellular invasiveness and survival inside different cell lines are pathogenic factors related to the ability of M. abscessus to establish infection. Some of the molecular factors involved in this process are well-known and are present in the mycobacterial cell wall, such as trehalose-dimycolate and glycopeptidolipids. The ability to form biofilms is another pathogenic factor that is essential for the development of chronic disease and for promoting mycobacterial survival against the host immune system or different antibacterial treatments. This capability also seems to be related to glycopeptidolipids and other lipid molecules, and some studies have shown an intrinsic relationship between both pathogenic mechanisms. Antimicrobial resistance is also considered a mechanism of pathogenicity because it allows the mycobacterium to resist antimicrobial therapies and represents an advantage in polymicrobial biofilms. The recent description of hyperpathogenic strains with the potential interhuman transmission makes it necessary to increase our knowledge of pathogenic mechanisms of this species to design better therapeutic approaches to the management of these infections.
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14
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Le Moigne V, Blouquit-Laye S, Desquesnes A, Girard-Misguich F, Herrmann JL. Liposomal amikacin and Mycobacterium abscessus: intimate interactions inside eukaryotic cells. J Antimicrob Chemother 2022; 77:3496-3503. [PMID: 36253948 DOI: 10.1093/jac/dkac348] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 09/26/2022] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Mycobacterium abscessus (Mabs), a rapidly growing Mycobacterium species, is considered an MDR organism. Among the standard antimicrobial multi-drug regimens against Mabs, amikacin is considered as one of the most effective. Parenteral amikacin, as a consequence of its inability to penetrate inside the cells, is only active against extracellular mycobacteria. The use of inhaled liposomal amikacin may yield improved intracellular efficacy by targeting Mabs inside the cells, while reducing its systemic toxicity. OBJECTIVES To evaluate the colocalization of an amikacin liposomal inhalation suspension (ALIS) with intracellular Mabs, and then to measure its intracellular anti-Mabs activity. METHODS We evaluated the colocalization of ALIS with Mabs in eukaryotic cells such as macrophages (THP-1 and J774.2) or pulmonary epithelial cells (BCi-NS1.1 and MucilAir), using a fluorescent ALIS and GFP-expressing Mabs, to test whether ALIS reaches intracellular Mabs. We then evaluated the intracellular anti-Mabs activity of ALIS inside macrophages using cfu and/or luminescence. RESULTS Using confocal microscopy, we demonstrated fluorescent ALIS and GFP-Mabs colocalization in macrophages and epithelial cells. We also showed that ALIS was active against intracellular Mabs at a concentration of 32 to 64 mg/L, at 3 and 5 days post-infection. Finally, ALIS intracellular activity was confirmed when tested against 53 clinical Mabs isolates, showing intracellular growth reduction for nearly 80% of the isolates. CONCLUSIONS Our experiments demonstrate the intracellular localization and intracellular contact between Mabs and ALIS, and antibacterial activity against intracellular Mabs, showing promise for its future use for Mabs pulmonary infections.
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Affiliation(s)
- Vincent Le Moigne
- Pensez à respecter la signature institutionnelle (think to respect the institutional signature): Université Paris-Saclay, UVSQ, Inserm, Infection et inflammation, 78180, Montigny-Le-Bretonneux, France
| | - Sabine Blouquit-Laye
- Pensez à respecter la signature institutionnelle (think to respect the institutional signature): Université Paris-Saclay, UVSQ, Inserm, Infection et inflammation, 78180, Montigny-Le-Bretonneux, France
| | - Aurore Desquesnes
- Pensez à respecter la signature institutionnelle (think to respect the institutional signature): Université Paris-Saclay, UVSQ, Inserm, Infection et inflammation, 78180, Montigny-Le-Bretonneux, France
| | - Fabienne Girard-Misguich
- Pensez à respecter la signature institutionnelle (think to respect the institutional signature): Université Paris-Saclay, UVSQ, Inserm, Infection et inflammation, 78180, Montigny-Le-Bretonneux, France
| | - Jean-Louis Herrmann
- Pensez à respecter la signature institutionnelle (think to respect the institutional signature): Université Paris-Saclay, UVSQ, Inserm, Infection et inflammation, 78180, Montigny-Le-Bretonneux, France.,AP-HP, GHU Paris-Saclay, Hôpital Raymond Poincaré, Service de Microbiologie, Garches, France
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15
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Kam JY, Wright K, Britton WJ, Oehlers SH. Treatment of infection-induced vascular pathologies is protective against persistent rough morphotype Mycobacterium abscessus infection in zebrafish. Microb Pathog 2022; 167:105590. [PMID: 35588967 DOI: 10.1016/j.micpath.2022.105590] [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: 12/30/2021] [Revised: 04/25/2022] [Accepted: 05/10/2022] [Indexed: 11/30/2022]
Abstract
Mycobacterium abscessus infections are of increasing global prevalence and are often difficult to treat due to complex antibiotic resistance profiles. While there are similarities between the pathogenesis of M. abscessus and tuberculous mycobacteria, including granuloma formation and stromal remodelling, there are distinct molecular differences at the host-pathogen interface. Here we have used a zebrafish-M. abscessus model and host-directed therapies that were previously identified in the zebrafish-M. marinum model to identify potential host-directed therapies against M. abscessus infection. We find efficacy of anti-angiogenic and vascular normalizing therapies against rough M. abscessus infection, but no effect of anti-platelet drugs.
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Affiliation(s)
- Julia Y Kam
- Tuberculosis Research Program at the Centenary Institute, The University of Sydney, Camperdown, NSW, 2050, Australia
| | - Kathryn Wright
- Tuberculosis Research Program at the Centenary Institute, The University of Sydney, Camperdown, NSW, 2050, Australia
| | - Warwick J Britton
- Tuberculosis Research Program at the Centenary Institute, The University of Sydney, Camperdown, NSW, 2050, Australia; Department of Clinical Immunology, Royal Prince Alfred Hospital, Camperdown, NSW, 2050, Australia
| | - Stefan H Oehlers
- Tuberculosis Research Program at the Centenary Institute, The University of Sydney, Camperdown, NSW, 2050, Australia; The University of Sydney, Sydney Institute for Infectious Diseases, Camperdown, NSW, 2050, Australia; A*STAR Infectious Diseases Labs (A*STAR ID Labs), Agency for Science, Technology and Research (A*STAR), Singapore 138648, Singapore.
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16
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Ferrell KC, Johansen MD, Triccas JA, Counoupas C. Virulence Mechanisms of Mycobacterium abscessus: Current Knowledge and Implications for Vaccine Design. Front Microbiol 2022; 13:842017. [PMID: 35308378 PMCID: PMC8928063 DOI: 10.3389/fmicb.2022.842017] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 02/08/2022] [Indexed: 12/22/2022] Open
Abstract
Mycobacterium abscessus is a member of the non-tuberculous mycobacteria (NTM) group, responsible for chronic infections in individuals with cystic fibrosis (CF) or those otherwise immunocompromised. While viewed traditionally as an opportunistic pathogen, increasing research into M. abscessus in recent years has highlighted its continued evolution into a true pathogen. This is demonstrated through an extensive collection of virulence factors (VFs) possessed by this organism which facilitate survival within the host, particularly in the harsh environment of the CF lung. These include VFs resembling those of other Mycobacteria, and non-mycobacterial VFs, both of which make a notable contribution in shaping M. abscessus interaction with the host. Mycobacterium abscessus continued acquisition of VFs is cause for concern and highlights the need for novel vaccination strategies to combat this pathogen. An effective M. abscessus vaccine must be suitably designed for target populations (i.e., individuals with CF) and incorporate current knowledge on immune correlates of protection against M. abscessus infection. Vaccination strategies must also build upon lessons learned from ongoing efforts to develop novel vaccines for other pathogens, particularly Mycobacterium tuberculosis (M. tb); decades of research into M. tb has provided insight into unconventional and innovative vaccine approaches that may be applied to M. abscessus. Continued research into M. abscessus pathogenesis will be critical for the future development of safe and effective vaccines and therapeutics to reduce global incidence of this emerging pathogen.
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Affiliation(s)
- Kia C. Ferrell
- School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Camperdown, NSW, Australia
- Tuberculosis Research Program, Centenary Institute, Sydney, NSW, Australia
- *Correspondence: Kia C. Ferrell,
| | - Matt D. Johansen
- Centre for Inflammation, Centenary Institute, University of Technology, Sydney, NSW, Australia
- Faculty of Science, School of Life Sciences, University of Technology, Sydney, NSW, Australia
| | - James A. Triccas
- School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Camperdown, NSW, Australia
- Sydney Institute for Infectious Diseases and the Charles Perkins Centre, The University of Sydney, Camperdown, NSW, Australia
| | - Claudio Counoupas
- School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Camperdown, NSW, Australia
- Tuberculosis Research Program, Centenary Institute, Sydney, NSW, Australia
- Sydney Institute for Infectious Diseases and the Charles Perkins Centre, The University of Sydney, Camperdown, NSW, Australia
- Claudio Counoupas,
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17
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Kam JY, Hortle E, Krogman E, Warner SE, Wright K, Luo K, Cheng T, Manuneedhi Cholan P, Kikuchi K, Triccas JA, Britton WJ, Johansen MD, Kremer L, Oehlers SH. Rough and smooth variants of Mycobacterium abscessus are differentially controlled by host immunity during chronic infection of adult zebrafish. Nat Commun 2022; 13:952. [PMID: 35177649 PMCID: PMC8854618 DOI: 10.1038/s41467-022-28638-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 02/03/2022] [Indexed: 11/09/2022] Open
Abstract
Prevalence of Mycobacterium abscessus infections is increasing in patients with respiratory comorbidities. After initial colonisation, M. abscessus smooth colony (S) variants can undergo an irreversible genetic switch into highly inflammatory, rough colony (R) variants, often associated with a decline in pulmonary function. Here, we use an adult zebrafish model of chronic infection with R and S variants to study M. abscessus pathogenesis in the context of fully functioning host immunity. We show that infection with an R variant causes an inflammatory immune response that drives necrotic granuloma formation through host TNF signalling, mediated by the tnfa, tnfr1 and tnfr2 gene products. T cell-dependent immunity is stronger against the R variant early in infection, and regulatory T cells associate with R variant granulomas and limit bacterial growth. In comparison, an S variant proliferates to high burdens but appears to be controlled by TNF-dependent innate immunity early during infection, resulting in delayed granuloma formation. Thus, our work demonstrates the applicability of adult zebrafish to model persistent M. abscessus infection, and illustrates differences in the immunopathogenesis induced by R and S variants during granulomatous infection. The pathogen Mycobacterium abscessus can switch from a smooth colony form (S) into a highly inflammatory, rough colony form (R) during infection. Here, Kam et al. use an adult zebrafish model of M. abscessus chronic infection to illustrate differences in the immunopathogenesis induced by R and S variants.
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Affiliation(s)
- Julia Y Kam
- Tuberculosis Research Program at the Centenary Institute, The University of Sydney, Camperdown, NSW, Australia
| | - Elinor Hortle
- Tuberculosis Research Program at the Centenary Institute, The University of Sydney, Camperdown, NSW, Australia.,The University of Sydney, Faculty of Medicine and Health & Marie Bashir Institute, Camperdown, NSW, Australia
| | - Elizabeth Krogman
- Tuberculosis Research Program at the Centenary Institute, The University of Sydney, Camperdown, NSW, Australia
| | - Sherridan E Warner
- Tuberculosis Research Program at the Centenary Institute, The University of Sydney, Camperdown, NSW, Australia.,The University of Sydney, Faculty of Medicine and Health & Marie Bashir Institute, Camperdown, NSW, Australia
| | - Kathryn Wright
- Tuberculosis Research Program at the Centenary Institute, The University of Sydney, Camperdown, NSW, Australia
| | - Kaiming Luo
- Tuberculosis Research Program at the Centenary Institute, The University of Sydney, Camperdown, NSW, Australia
| | - Tina Cheng
- Tuberculosis Research Program at the Centenary Institute, The University of Sydney, Camperdown, NSW, Australia
| | - Pradeep Manuneedhi Cholan
- Tuberculosis Research Program at the Centenary Institute, The University of Sydney, Camperdown, NSW, Australia
| | - Kazu Kikuchi
- Developmental and Stem Cell Biology Division, Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia.,St. Vincent's Clinical School, University of New South Wales, Kensington, NSW, Australia
| | - James A Triccas
- The University of Sydney, Faculty of Medicine and Health & Marie Bashir Institute, Camperdown, NSW, Australia
| | - Warwick J Britton
- Tuberculosis Research Program at the Centenary Institute, The University of Sydney, Camperdown, NSW, Australia.,Department of Clinical Immunology, Royal Prince Alfred Hospital, Camperdown, NSW, Australia
| | - Matt D Johansen
- Centre National de la Recherche Scientifique UMR 9004, Institut de Recherche en Infectiologie de Montpellier (IRIM), Université de Montpellier, Montpellier, France
| | - Laurent Kremer
- Centre National de la Recherche Scientifique UMR 9004, Institut de Recherche en Infectiologie de Montpellier (IRIM), Université de Montpellier, Montpellier, France.,INSERM, IRIM, Montpellier, France
| | - Stefan H Oehlers
- Tuberculosis Research Program at the Centenary Institute, The University of Sydney, Camperdown, NSW, Australia. .,The University of Sydney, Faculty of Medicine and Health & Marie Bashir Institute, Camperdown, NSW, Australia. .,A*STAR Infectious Diseases Labs, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore.
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18
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Elimination of PknL and MSMEG_4242 in Mycobacterium smegmatis alters the character of the outer cell envelope and selects for mutations in Lsr2. ACTA ACUST UNITED AC 2021; 7:100060. [PMID: 34485766 PMCID: PMC8408660 DOI: 10.1016/j.tcsw.2021.100060] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2021] [Revised: 08/12/2021] [Accepted: 08/13/2021] [Indexed: 11/23/2022]
Abstract
Elimination of pknL and adjacent gene MSMEG_4242 in M. smegmatis produces rough & smooth colonies. All smooth colony mutants have inactivated lsr2 genes. Inactivated lsr2 leads to high expression of MSMEG_4727 and increased synthesis of LOS. Smooth mutants don’t form biofilms, have longer bacilli and increased sliding motility. Rough strains deleted for pknL and MSMEG_4242 form biofilms but have aberrant sliding motility. We propose a phosphorylation cascade of PknB phosphorylating PknL that then phosphorylates Lsr2.
Four serine/threonine kinases are present in all mycobacteria: PknA, PknB, PknG and PknL. PknA and PknB are essential for growth and replication, PknG regulates metabolism, but little is known about PknL. Inactivation of pknL and adjacent regulator MSMEG_4242 in rough colony M. smegmatis mc2155 produced both smooth and rough colonies. Upon restreaking rough colonies, smooth colonies appeared at a frequency of ~ 1/250. Smooth mutants did not form biofilms, showed increased sliding motility and anomalous lipids on thin-layer chromatography, identified by mass spectrometry as lipooligosaccharides and perhaps also glycopeptidolipids. RNA-seq and Sanger sequencing revealed that all smooth mutants had inactivated lsr2 genes due to mutations and different IS1096 insertions. When complemented with lsr2, the colonies became rough, anomalous lipids disappeared and sliding motility decreased. Smooth mutants showed increased expression of IS1096 transposase TnpA and MSMEG_4727, which encodes a protein similar to PKS5. When MSMEG_4727 was deleted, smooth pknL/MSMEG_4242/lsr2 mutants reverted to rough, formed good biofilms, their motility decreased slightly and their anomalous lipids disappeared. Rough delpknL/del4242 mutants formed poor biofilms and showed decreased, aberrant sliding motility and both phenotypes were complemented with the two deleted genes. Inactivation of lsr2 changes colony morphology from rough to smooth, augments sliding motility and increases expression of MSMEG_4727 and other enzymes synthesizing lipooligosaccharides, apparently preventing biofilm formation. Similar morphological phase changes occur in other mycobacteria, likely reflecting environmental adaptations. PknL and MSMEG_4242 regulate lipid components of the outer cell envelope and their absence selects for lsr2 inactivation. A regulatory, phosphorylation cascade model is proposed.
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19
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NOD2/c-Jun NH 2-Terminal Kinase Triggers Mycoplasma ovipneumoniae-Induced Macrophage Autophagy. J Bacteriol 2020; 202:JB.00689-19. [PMID: 32778560 PMCID: PMC7515247 DOI: 10.1128/jb.00689-19] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 07/29/2020] [Indexed: 02/07/2023] Open
Abstract
Mycoplasma ovipneumoniae belongs to Mycoplasma, a genus containing the smallest self-replicating microorganisms, and causes infectious pleuropneumonia in goats and sheep. Nucleotide-binding oligomerization domain-containing protein (NOD2), an intracellular pattern recognition receptor, interacts with muramyl dipeptide (MDP) to recognize bacterial peptidoglycans and is involved in autophagy induction. However, there have been no reports about NOD recognition of mycoplasmas or M. ovipneumoniae-induced autophagy. In this study, we sought to determine the role of NOD2 in M. ovipneumoniae-induced autophagy using Western blotting, immunofluorescence, real-time PCR (RT-PCR), and color-changing unit (CCU) analysis. M. ovipneumoniae infection markedly increased NOD2 but did not increase NOD1 expression in RAW 264.7 cells. Treating RAW 264.7 cells with MDP significantly increased colocalization of M. ovipneumoniae and LC3, whereas treatment with NOD inhibitor, NOD-IN-1, decreased colocalization of M. ovipneumoniae and LC3. Furthermore, suppressing NOD2 expression with small interfering RNA (siRNA)-NOD2 failed to trigger M. ovipneumoniae-induced autophagy by detecting autophagy markers Atg5, beclin1, and LC3-II. In addition, M. ovipneumoniae infection significantly increased the phosphorylated c-Jun NH2-terminal kinase (p-JNK)/JNK, p-Bcl-2/Bcl-2, beclin1, Atg5, and LC3-II ratios in RAW 264.7 cells. Treatment with JNK inhibitor, SP600126, or siRNA-NOD2 did not increase this reaction. These findings suggested that M. ovipneumoniae infection activated NOD2, and both NOD2 and JNK pathway activation promoted M. ovipneumoniae-induced autophagy. This study provides new insight into the NOD2 reorganization mechanism and the pathogenesis of M. ovipneumoniae infection.IMPORTANCE M. ovipneumoniae, which lacks a cell wall, causes infectious pleuropneumonia in goats and sheep. In the present study, we focused on the interaction between NOD and M. ovipneumoniae, as well as its association with autophagy. We showed for the first time that NOD2 was activated by M. ovipneumoniae even when peptidoglycans were not present. We also observed that both NOD2 and JNK pathway activation promoted M. ovipneumoniae-induced autophagy.
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20
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de Alcântara NR, de Oliveira FM, Garcia W, Dos Santos OAL, Junqueira-Kipnis AP, Kipnis A. Dps protein is related to resistance of Mycobacterium abscessus subsp. massiliense against stressful conditions. Appl Microbiol Biotechnol 2020; 104:5065-5080. [PMID: 32253472 DOI: 10.1007/s00253-020-10586-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 03/18/2020] [Accepted: 03/24/2020] [Indexed: 02/06/2023]
Abstract
Mycobacterium abscessus subsp. massiliense (Mycma) belongs to the Mycobacterium abscessus complex and is a rapidly growing non-tuberculous mycobacterium. The chronic pulmonary, skin, and soft tissue infections that it causes may be difficult to treat due to its intrinsic resistance to the commonly used antimicrobial drugs, making it a serious world public health problem. Iron is an essential nutrient for the growth of microorganisms; nonetheless, it can be toxic when in excess. Thus, bacteria require an iron homeostasis mechanism to succeed in different environments. DNA-binding proteins from starved cells (Dps) are miniferritins with the property to act as additional iron storage proteins but also can bind to DNA, protecting it against hydroxyl radical. Annotation of the Mycma genome revealed the gene mycma_03135 with 79% sequential identity when compared to MSMEG_3242 gene from M. smegmatis mc2 155, which codifies for a known Dps. Recombinant Dps from M. abscessus (rMaDps) was produced in Escherichia coli, purified in soluble form and shown to form high mass oligomers in solution with ferroxidase activity, DNA binding, and protection against damage. The expression of the mycma_03135 gene was induced during Mycma growth in the presence of hydrogen peroxide (H2O2). Additionally, the expression of rMaDps by E. coli conferred greater resistance to H2O2. Thus, this study is the first to identify and characterize a Dps from M. abscessus. KEY POINTS: Mycobacterium abscessus subsp. massiliense express a miniferritin protein (Dps). Mycma Dps binds to DNA and protects against oxidative stress.
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Affiliation(s)
| | - Fábio Muniz de Oliveira
- Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, GO, Brazil
| | - Wanius Garcia
- Centro de Ciências Naturais e Humanas, Universidade Federal do ABC (UFABC), Santo André, SP, Brazil
| | | | | | - André Kipnis
- Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, GO, Brazil.
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21
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Johansen MD, Herrmann JL, Kremer L. Non-tuberculous mycobacteria and the rise of Mycobacterium abscessus. Nat Rev Microbiol 2020; 18:392-407. [PMID: 32086501 DOI: 10.1038/s41579-020-0331-1] [Citation(s) in RCA: 364] [Impact Index Per Article: 91.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/15/2020] [Indexed: 12/17/2022]
Abstract
Infections caused by non-tuberculous mycobacteria (NTM) are increasing globally and are notoriously difficult to treat due to intrinsic resistance of these bacteria to many common antibiotics. NTM are diverse and ubiquitous in the environment, with only a few species causing serious and often opportunistic infections in humans, including Mycobacterium abscessus. This rapidly growing mycobacterium is one of the most commonly identified NTM species responsible for severe respiratory, skin and mucosal infections in humans. It is often regarded as one of the most antibiotic-resistant mycobacteria, leaving us with few therapeutic options. In this Review, we cover the proposed infection process of M. abscessus, its virulence factors and host interactions and highlight the commonalities and differences of M. abscessus with other NTM species. Finally, we discuss drug resistance mechanisms and future therapeutic options. Taken together, this knowledge is essential to further our understanding of this overlooked and neglected global threat.
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Affiliation(s)
- Matt D Johansen
- Institut de Recherche en Infectiologie de Montpellier, Centre National de la Recherche Scientifique UMR 9004, Université de Montpellier, Montpellier, France
| | - Jean-Louis Herrmann
- Université Paris-Saclay, UVSQ, Inserm, Infection et Inflammation, Montigny-Le-Bretonneux, France.,AP-HP. GHU Paris Saclay, Hôpital Raymond Poincaré, Garches, France
| | - Laurent Kremer
- Institut de Recherche en Infectiologie de Montpellier, Centre National de la Recherche Scientifique UMR 9004, Université de Montpellier, Montpellier, France. .,Inserm, Institut de Recherche en Infectiologie de Montpellier, Montpellier, France.
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