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Urtasun-Elizari JM, Ma R, Pickford H, Farrell D, Gonzalez G, Perets V, Nakajima C, Suzuki Y, MacHugh DE, Bhatt A, Gordon SV. Functional analysis of the Mycobacterium bovis AF2122/97 PhoPR system. Tuberculosis (Edinb) 2024; 148:102544. [PMID: 39018651 DOI: 10.1016/j.tube.2024.102544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2024] [Revised: 06/25/2024] [Accepted: 07/12/2024] [Indexed: 07/19/2024]
Abstract
The PhoPR system is a master regulator in Mycobacterium tuberculosis. A key difference between M. tuberculosis and Mycobacterium bovis is a G71I substitution in the M. bovis PhoR orthologue. Functional studies of the M. bovis PhoPR system have generated conflicting findings, with some research suggesting that the M. bovis PhoPR is defective while others indicate it is functional. We sought to revisit the functionality of the M. bovis PhoPR system. To address this, we constructed a phoPR mutant in the reference strain M. bovis AF2122/97. We employed a combination of growth assays and transcriptomics analyses to assess the phenotype of the mutant vs wild type and complemented strains. We found that the M. bovis AF2122/97 ΔphoPR mutant showed a growth defect on solid and liquid media compared to the wild type and complemented strains. The transcriptome of the M. bovis AF2122/97 ΔphoPR mutant was also altered as compared to wild type, including differential expression of genes involved in lipid metabolism and secretion. Our work provides further insight into the activity of PhoPR in M. bovis and underlines the importance of the PhoPR system as a master regulator of gene expression in the Mycobacterium tuberculosis complex.
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Affiliation(s)
| | - Ruoyao Ma
- UCD School of Veterinary Medicine, University College Dublin, Belfield, Dublin, D04 V1W8, Ireland
| | - Hayleah Pickford
- School of Biosciences and Institute of Microbiology and Infection, University of Birmingham, Birmingham, B15 2TT, UK
| | - Damien Farrell
- UCD School of Veterinary Medicine, University College Dublin, Belfield, Dublin, D04 V1W8, Ireland
| | - Gabriel Gonzalez
- International Institute for Vaccine Research and Development, Hokkaido University, Kita 21, Nishi 11, Kita-ku, Sapporo, 001-0021, Japan
| | - Viktor Perets
- UCD School of Veterinary Medicine, University College Dublin, Belfield, Dublin, D04 V1W8, Ireland
| | - Chie Nakajima
- International Institute for Vaccine Research and Development, Hokkaido University, Kita 21, Nishi 11, Kita-ku, Sapporo, 001-0021, Japan; International Institute for Zoonosis Control, Hokkaido University, Kita 20, Nishi 10, Kita-ku, Sapporo, 001-0020, Japan
| | - Yasuhiko Suzuki
- International Institute for Vaccine Research and Development, Hokkaido University, Kita 21, Nishi 11, Kita-ku, Sapporo, 001-0021, Japan; International Institute for Zoonosis Control, Hokkaido University, Kita 20, Nishi 10, Kita-ku, Sapporo, 001-0020, Japan
| | - David E MacHugh
- UCD School of Agriculture and Food Science, University College Dublin, Belfield, Dublin, D04 V1W8, Ireland; UCD Conway Institute of Biomolecular and Biomedical Science, University College Dublin, Belfield, Dublin, D04 V1W8, Ireland; UCD Centre for One Health, University College Dublin, Belfield, Dublin, Ireland
| | - Apoorva Bhatt
- School of Biosciences and Institute of Microbiology and Infection, University of Birmingham, Birmingham, B15 2TT, UK
| | - Stephen V Gordon
- UCD School of Veterinary Medicine, University College Dublin, Belfield, Dublin, D04 V1W8, Ireland; International Institute for Vaccine Research and Development, Hokkaido University, Kita 21, Nishi 11, Kita-ku, Sapporo, 001-0021, Japan; International Institute for Zoonosis Control, Hokkaido University, Kita 20, Nishi 10, Kita-ku, Sapporo, 001-0020, Japan; UCD Conway Institute of Biomolecular and Biomedical Science, University College Dublin, Belfield, Dublin, D04 V1W8, Ireland; UCD Centre for One Health, University College Dublin, Belfield, Dublin, Ireland; UCD Centre for Experimental Pathogen Host Research, University College Dublin, Belfield, Dublin, Ireland.
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2
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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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3
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Sunita, Singhvi N, Gupta V, Singh Y, Shukla P. Computational Approaches for the Structure-Based Identification of Novel Inhibitors Targeting Nucleoid-Associated Proteins in Mycobacterium Tuberculosis. Mol Biotechnol 2024; 66:814-823. [PMID: 36913083 DOI: 10.1007/s12033-023-00710-5] [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: 06/09/2022] [Accepted: 02/24/2023] [Indexed: 03/14/2023]
Abstract
Implementation of computational tools in the identification of novel drug targets for Tuberculosis (TB) has been a promising area of research. TB has been a chronic infectious disease caused by Mycobacterium tuberculosis (Mtb) localized primarily on the lungs and it has been one of the most successful pathogen in the history of mankind. Extensively arising drug resistivity in TB has made it a global challenge and need for new drugs has become utmost important.The involvement of Nucleoid-Associated Proteins (NAPs) in maintaining the structure of the genomic material and regulating various cellular processes like transcription, DNA replication, repair and recombination makes significant, has opened a new arena to find the drugs targeting Mtb. The current study aims to identify potential inhibitors of NAPs through a computational approach. In the present work we worked on the eight NAPs of Mtb, namely, Lsr2, EspR, HupB, HNS, NapA, mIHF and NapM. The structural modelling and analysis of these NAPs were carried out. Moreover, molecular interaction were checked and binding energy was identified for 2500 FDA-approved drugs that were selected for antagonist analysis to choose novel inhibitors targeting NAPs of Mtb. Drugs including Amikacin, streptomycin, kanamycin, and isoniazid along with eight FDA-approved molecules that were found to be potential novel targets for these mycobacterial NAPs and have an impact on their functions. The potentiality of several anti-tubercular drugs as therapeutic agents identified through computational modelling and simulation unlocks a new gateway for accomplishing the goal to treat TB.
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Affiliation(s)
- Sunita
- Department of Microbiology, Maharshi Dayanand University, Rohtak, 124001, Haryana, India
- Bacterial Pathogenesis Laboratory, Department of Zoology, University of Delhi, Delhi, 110007, India
| | - Nirjara Singhvi
- Department of Zoology, Hansraj College, University of Delhi, Delhi, 110007, India
- School of Allied Sciences, Dev Bhoomi Uttarakhand University, Dehradun, Uttarakhand, 248001, India
| | - Vipin Gupta
- Ministry of Environment, Forest and Climate Change, Government of India, Dehradun, Uttarakhand, 248001, India
| | - Yogendra Singh
- Bacterial Pathogenesis Laboratory, Department of Zoology, University of Delhi, Delhi, 110007, India
| | - Pratyoosh Shukla
- Department of Microbiology, Maharshi Dayanand University, Rohtak, 124001, Haryana, India.
- Enzyme Technology and Protein Bioinformatics Laboratory, School of Biotechnology, Institute of Science, Banaras Hindu University, Varanasi, 221005, India.
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4
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Chumsakul O, Nakamura K, Fukamachi K, Ishikawa S, Oshima T. GeF-seq: A Simple Procedure for Base-Pair Resolution ChIP-seq. Methods Mol Biol 2024; 2819:39-53. [PMID: 39028501 DOI: 10.1007/978-1-0716-3930-6_3] [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] [Indexed: 07/20/2024]
Abstract
Nucleotide sequences recognized and bound by DNA-binding proteins (DBPs) are critical to controlling and maintaining gene expression, replication, chromosome segregation, cell division, and nucleoid structure in bacterial cells. Therefore, determination of the binding sequences of DBPs is important not only to study DBP recognition mechanisms but also to understand the fundamentals of cell homeostasis. While ChIP-seq analysis appears to be an effective way to determine DBP binding sites on the genome, the resolution is sometimes not sufficient to identify the sites precisely. Here we introduce a simple and effective method named Genome Footprinting with high-throughput sequencing (GeF-seq) to determine binding sites of DBPs with single base-pair resolution. GeF-seq detects binding sites of DBPs as sharp peaks and thus makes it possible to identify the recognition sequence in each "binding peak" more easily and accurately compared to the common ChIP-seq.
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Affiliation(s)
- Onuma Chumsakul
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara, Japan
- Basic Research and Development Division, Rohto Pharmaceutical Co., Ltd., Kyoto, Japan
- Graduate School of Science, Technology and Innovation, Kobe University, Noda, Kobe, Japan
| | - Kensuke Nakamura
- Division of Informatics, Bioengineering and Bioscience, Maebashi Institute of Technology, Maebashi, Gunma, Japan
| | - Kazuki Fukamachi
- Department of Biotechnology, Toyama Prefectural University, Imizu, Toyama, Japan
| | - Shu Ishikawa
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara, Japan.
- Graduate School of Science, Technology and Innovation, Kobe University, Noda, Kobe, Japan.
| | - Taku Oshima
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara, Japan.
- Department of Biotechnology, Toyama Prefectural University, Imizu, Toyama, Japan.
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5
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Keshavam CC, Naz S, Gupta A, Sanyal P, Kochar M, Gangwal A, Sangwan N, Kumar N, Tyagi E, Goel S, Singh NK, Sowpati DT, Khare G, Ganguli M, Raze D, Locht C, Basu-Modak S, Gupta M, Nandicoori VK, Singh Y. The heparin-binding hemagglutinin protein of Mycobacterium tuberculosis is a nucleoid-associated protein. J Biol Chem 2023; 299:105364. [PMID: 37865319 PMCID: PMC10665949 DOI: 10.1016/j.jbc.2023.105364] [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: 08/08/2023] [Revised: 10/05/2023] [Accepted: 10/10/2023] [Indexed: 10/23/2023] Open
Abstract
Nucleoid-associated proteins (NAPs) regulate multiple cellular processes such as gene expression, virulence, and dormancy throughout bacterial species. NAPs help in the survival and adaptation of Mycobacterium tuberculosis (Mtb) within the host. Fourteen NAPs have been identified in Escherichia coli; however, only seven NAPs are documented in Mtb. Given its complex lifestyle, it is reasonable to assume that Mtb would encode for more NAPs. Using bioinformatics tools and biochemical experiments, we have identified the heparin-binding hemagglutinin (HbhA) protein of Mtb as a novel sequence-independent DNA-binding protein which has previously been characterized as an adhesion molecule required for extrapulmonary dissemination. Deleting the carboxy-terminal domain of HbhA resulted in a complete loss of its DNA-binding activity. Atomic force microscopy showed HbhA-mediated architectural modulations in the DNA, which may play a regulatory role in transcription and genome organization. Our results showed that HbhA colocalizes with the nucleoid region of Mtb. Transcriptomics analyses of a hbhA KO strain revealed that it regulates the expression of ∼36% of total and ∼29% of essential genes. Deletion of hbhA resulted in the upregulation of ∼73% of all differentially expressed genes, belonging to multiple pathways suggesting it to be a global repressor. The results show that HbhA is a nonessential NAP regulating gene expression globally and acting as a plausible transcriptional repressor.
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Affiliation(s)
| | - Saba Naz
- Department of Zoology, University of Delhi, Delhi, India; CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India
| | - Aanchal Gupta
- CSIR-Institute of Genomics and Integrative Biology, New Delhi, India
| | - Priyadarshini Sanyal
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India; Academy of Scientific and Innovative Research (AcSIR), CSIR- Centre for Cellular and Molecular Biology (CSIR-CCMB) Campus, Hyderabad, India
| | - Manisha Kochar
- Department of Zoology, University of Delhi, Delhi, India; CSIR-Institute of Genomics and Integrative Biology, New Delhi, India
| | | | - Nitika Sangwan
- Department of Zoology, University of Delhi, Delhi, India
| | - Nishant Kumar
- Department of Zoology, University of Delhi, Delhi, India
| | - Ekta Tyagi
- Department of Zoology, University of Delhi, Delhi, India
| | - Simran Goel
- Department of Zoology, University of Delhi, Delhi, India
| | | | | | - Garima Khare
- Department of Biochemistry, University of Delhi South Campus, New Delhi, India
| | - Munia Ganguli
- CSIR-Institute of Genomics and Integrative Biology, New Delhi, India
| | - Dominique Raze
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019 - UMR9017 - CIIL - Centre for Infection and Immunity of Lille, Lille, France
| | - Camille Locht
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019 - UMR9017 - CIIL - Centre for Infection and Immunity of Lille, Lille, France
| | | | - Meetu Gupta
- CSIR-Institute of Genomics and Integrative Biology, New Delhi, India.
| | - Vinay Kumar Nandicoori
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India; Academy of Scientific and Innovative Research (AcSIR), CSIR- Centre for Cellular and Molecular Biology (CSIR-CCMB) Campus, Hyderabad, India; National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, India.
| | - Yogendra Singh
- Department of Zoology, University of Delhi, Delhi, India; Delhi School of Public Health, Institution of Eminence, University of Delhi, Delhi, India.
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6
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Li S, Liu Q, Duan C, Li J, Sun H, Xu L, Yang Q, Wang Y, Shen X, Zhang L. c-di-GMP inhibits the DNA binding activity of H-NS in Salmonella. Nat Commun 2023; 14:7502. [PMID: 37980414 PMCID: PMC10657408 DOI: 10.1038/s41467-023-43442-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Accepted: 11/09/2023] [Indexed: 11/20/2023] Open
Abstract
Cyclic di-GMP (c-di-GMP) is a second messenger that transduces extracellular stimuli into cellular responses and regulates various biological processes in bacteria. H-NS is a global regulatory protein that represses expression of many genes, but how H-NS activity is modulated by environmental signals remains largely unclear. Here, we show that high intracellular c-di-GMP levels, induced by environmental cues, relieve H-NS-mediated transcriptional silencing in Salmonella enterica serovar Typhimurium. We find that c-di-GMP binds to the H-NS protein to inhibit its binding to DNA, thus derepressing genes silenced by H-NS. However, c-di-GMP is unable to displace H-NS from DNA. In addition, a K107A mutation in H-NS abolishes response to c-di-GMP but leaves its DNA binding activity unaffected in vivo. Our results thus suggest a mechanism by which H-NS acts as an environment-sensing regulator in Gram-negative bacteria.
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Affiliation(s)
- Shuyu Li
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Qinmeng Liu
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Chongyi Duan
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Jialin Li
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Hengxi Sun
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Lei Xu
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Qiao Yang
- ABI Group, College of Marine Science and Technology, Zhejiang Ocean University, Zhoushan, 316021, China
- Donghai Laboratory, Zhoushan, 316021, China
| | - Yao Wang
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Xihui Shen
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, China.
| | - Lei Zhang
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, China.
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7
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Yandrapally S, Agarwal A, Chatterjee A, Sarkar S, Mohareer K, Banerjee S. Mycobacterium tuberculosis EspR modulates Th1-Th2 shift by transcriptionally regulating IL-4, steering increased mycobacterial persistence and HIV propagation during co-infection. Front Immunol 2023; 14:1276817. [PMID: 37928551 PMCID: PMC10621737 DOI: 10.3389/fimmu.2023.1276817] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2023] [Accepted: 10/06/2023] [Indexed: 11/07/2023] Open
Abstract
Mycobacterium tuberculosis (Mtb) and HIV are known to mutually support each other during co-infection by multiple mechanisms. This synergistic influence could be either by direct interactions or indirectly through secreted host or pathogen factors that work in trans. Mtb secretes several virulence factors to modulate the host cellular environment for its persistence and escaping cell-intrinsic immune responses. We hypothesized that secreted Mtb transcription factors that target the host nucleus can directly interact with host DNA element(s) or HIV LTR during co-infection, thereby modulating immune gene expression, or driving HIV transcription, helping the synergistic existence of Mtb and HIV. Here, we show that the Mtb-secreted protein, EspR, a transcription regulator, increased mycobacterial persistence and HIV propagation during co-infection. Mechanistically, EspR localizes to the nucleus of the host cells during infection, binds to its putative cognate motif on the promoter region of the host IL-4 gene, activating IL-4 gene expression, causing high IL-4 titers that induce a Th2-type microenvironment, shifting the macrophage polarization to an M2 state as evident from CD206 dominant population over CD64. This compromised the clearance of the intracellular mycobacteria and enhanced HIV propagation. It was interesting to note that EspR did not bind to HIV LTR, although its transient expression increased viral propagation. This is the first report of an Mtb transcription factor directly regulating a host cytokine gene. This augments our understanding of the evolution of Mtb immune evasion strategies and unveils how Mtb aggravates comorbidities, such as HIV co-infection, by modulating the immune microenvironment.
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8
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Meade RK, Long JE, Jinich A, Rhee KY, Ashbrook DG, Williams RW, Sassetti CM, Smith CM. Genome-wide screen identifies host loci that modulate Mycobacterium tuberculosis fitness in immunodivergent mice. G3 (BETHESDA, MD.) 2023; 13:jkad147. [PMID: 37405387 PMCID: PMC10468300 DOI: 10.1093/g3journal/jkad147] [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: 03/07/2023] [Revised: 06/05/2023] [Accepted: 06/27/2023] [Indexed: 07/06/2023]
Abstract
Genetic differences among mammalian hosts and among strains of Mycobacterium tuberculosis (Mtb) are well-established determinants of tuberculosis (TB) patient outcomes. The advent of recombinant inbred mouse panels and next-generation transposon mutagenesis and sequencing approaches has enabled dissection of complex host-pathogen interactions. To identify host and pathogen genetic determinants of Mtb pathogenesis, we infected members of the highly diverse BXD family of strains with a comprehensive library of Mtb transposon mutants (TnSeq). Members of the BXD family segregate for Mtb-resistant C57BL/6J (B6 or B) and Mtb-susceptible DBA/2J (D2 or D) haplotypes. The survival of each bacterial mutant was quantified within each BXD host, and we identified those bacterial genes that were differentially required for Mtb fitness across BXD genotypes. Mutants that varied in survival among the host family of strains were leveraged as reporters of "endophenotypes," each bacterial fitness profile directly probing specific components of the infection microenvironment. We conducted quantitative trait loci (QTL) mapping of these bacterial fitness endophenotypes and identified 140 host-pathogen QTL (hpQTL). We located a QTL hotspot on chromosome 6 (75.97-88.58 Mb) associated with the genetic requirement of multiple Mtb genes: Rv0127 (mak), Rv0359 (rip2), Rv0955 (perM), and Rv3849 (espR). Together, this screen reinforces the utility of bacterial mutant libraries as precise reporters of the host immunological microenvironment during infection and highlights specific host-pathogen genetic interactions for further investigation. To enable downstream follow-up for both bacterial and mammalian genetic research communities, all bacterial fitness profiles have been deposited into GeneNetwork.org and added into the comprehensive collection of TnSeq libraries in MtbTnDB.
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Affiliation(s)
- Rachel K Meade
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC 27710, USA
- University Program in Genetics and Genomics, Duke University, Durham, NC 27710, USA
| | - Jarukit E Long
- Department of Microbiology and Physiological Systems, UMass Chan Medical School, Worcester, MA 01655, USA
- Research Animal Diagnostic Services, Charles River Laboratories, Wilmington, MA 01887, USA
| | - Adrian Jinich
- Division of Infectious Diseases, Weill Cornell Medical College, New York, NY 10021, USA
| | - Kyu Y Rhee
- Division of Infectious Diseases, Weill Cornell Medical College, New York, NY 10021, USA
| | - David G Ashbrook
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Robert W Williams
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Christopher M Sassetti
- Department of Microbiology and Physiological Systems, UMass Chan Medical School, Worcester, MA 01655, USA
| | - Clare M Smith
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC 27710, USA
- University Program in Genetics and Genomics, Duke University, Durham, NC 27710, USA
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9
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Vargas R, Luna MJ, Freschi L, Marin M, Froom R, Murphy KC, Campbell EA, Ioerger TR, Sassetti CM, Farhat MR. Phase variation as a major mechanism of adaptation in Mycobacterium tuberculosis complex. Proc Natl Acad Sci U S A 2023; 120:e2301394120. [PMID: 37399390 PMCID: PMC10334774 DOI: 10.1073/pnas.2301394120] [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: 02/05/2023] [Accepted: 05/03/2023] [Indexed: 07/05/2023] Open
Abstract
Phase variation induced by insertions and deletions (INDELs) in genomic homopolymeric tracts (HT) can silence and regulate genes in pathogenic bacteria, but this process is not characterized in MTBC (Mycobacterium tuberculosis complex) adaptation. We leverage 31,428 diverse clinical isolates to identify genomic regions including phase-variants under positive selection. Of 87,651 INDEL events that emerge repeatedly across the phylogeny, 12.4% are phase-variants within HTs (0.02% of the genome by length). We estimated the in-vitro frameshift rate in a neutral HT at 100× the neutral substitution rate at [Formula: see text] frameshifts/HT/year. Using neutral evolution simulations, we identified 4,098 substitutions and 45 phase-variants to be putatively adaptive to MTBC (P < 0.002). We experimentally confirm that a putatively adaptive phase-variant alters the expression of espA, a critical mediator of ESX-1-dependent virulence. Our evidence supports the hypothesis that phase variation in the ESX-1 system of MTBC can act as a toggle between antigenicity and survival in the host.
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Affiliation(s)
- Roger Vargas
- Center for Computational Biomedicine, Harvard Medical School, Boston, MA02115
- Department of Biomedical Informatics, Harvard Medical School, Boston, MA02115
| | - Michael J. Luna
- Department of Microbiology and Physiological Systems, University of Massachusetts Chan Medical School, Worcester, MA01655
| | - Luca Freschi
- Department of Biomedical Informatics, Harvard Medical School, Boston, MA02115
| | - Maximillian Marin
- Department of Biomedical Informatics, Harvard Medical School, Boston, MA02115
| | - Ruby Froom
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY10065
- Laboratory of Host-Pathogen Biology, The Rockefeller University, New York, NY10065
| | - Kenan C. Murphy
- Department of Microbiology and Physiological Systems, University of Massachusetts Chan Medical School, Worcester, MA01655
| | | | - Thomas R. Ioerger
- Department of Computer Science and Engineering, Texas A&M University, College Station, TX77843
| | - Christopher M. Sassetti
- Department of Microbiology and Physiological Systems, University of Massachusetts Chan Medical School, Worcester, MA01655
| | - Maha Reda Farhat
- Department of Biomedical Informatics, Harvard Medical School, Boston, MA02115
- Pulmonary and Critical Care Medicine, Massachusetts General Hospital, Boston, MA02114
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10
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Meade RK, Long JE, Jinich A, Rhee KY, Ashbrook DG, Williams RW, Sassetti CM, Smith CM. Genome-wide screen identifies host loci that modulate M. tuberculosis fitness in immunodivergent mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.05.528534. [PMID: 36945430 PMCID: PMC10028809 DOI: 10.1101/2023.03.05.528534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/11/2023]
Abstract
Genetic differences among mammalian hosts and Mycobacterium tuberculosis ( Mtb ) strains determine diverse tuberculosis (TB) patient outcomes. The advent of recombinant inbred mouse panels and next-generation transposon mutagenesis and sequencing approaches has enabled dissection of complex host- pathogen interactions. To identify host and pathogen genetic determinants of Mtb pathogenesis, we infected members of the BXD family of mouse strains with a comprehensive library of Mtb transposon mutants (TnSeq). Members of the BXD family segregate for Mtb -resistant C57BL/6J (B6 or B ) and Mtb -susceptible DBA/2J (D2 or D ) haplotypes. The survival of each bacterial mutant was quantified within each BXD host, and we identified those bacterial genes that were differentially required for Mtb fitness across BXD genotypes. Mutants that varied in survival among the host family of strains were leveraged as reporters for "endophenotypes", each bacterial fitness profile directly probing specific components of the infection microenvironment. We conducted QTL mapping of these bacterial fitness endophenotypes and identified 140 h ost- p athogen quantitative trait loci ( hp QTL). We identified a QTL hotspot on chromosome 6 (75.97-88.58 Mb) associated with the genetic requirement of multiple Mtb genes; Rv0127 ( mak ), Rv0359 ( rip2 ), Rv0955 ( perM ), and Rv3849 ( espR ). Together, this screen reinforces the utility of bacterial mutant libraries as precise reporters of the host immunological microenvironment during infection and highlights specific host-pathogen genetic interactions for further investigation. To enable downstream follow-up for both bacterial and mammalian genetic research communities, all bacterial fitness profiles have been deposited into GeneNetwork.org and added into the comprehensive collection of TnSeq libraries in MtbTnDB.
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Affiliation(s)
- Rachel K. Meade
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC, USA
- University Program in Genetics and Genomics, Duke University, Durham, NC, USA
| | - Jarukit E. Long
- Department of Microbiology and Physiological Systems, UMass Chan Medical School, Worcester, MA, USA
- Charles River Laboratories, Research Animal Diagnostic Services, Wilmington, MA, USA
| | - Adrian Jinich
- Division of Infectious Diseases, Weill Cornell Medical College, NY, USA
| | - Kyu Y. Rhee
- Division of Infectious Diseases, Weill Cornell Medical College, NY, USA
| | - David G. Ashbrook
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Robert W. Williams
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Christopher M. Sassetti
- Department of Microbiology and Physiological Systems, UMass Chan Medical School, Worcester, MA, USA
| | - Clare M. Smith
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC, USA
- University Program in Genetics and Genomics, Duke University, Durham, NC, USA
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11
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Xie Y, Li J, Ding Y, Shao X, Sun Y, Xie F, Liu S, Tang S, Deng X. An atlas of bacterial two-component systems reveals function and plasticity in signal transduction. Cell Rep 2022; 41:111502. [DOI: 10.1016/j.celrep.2022.111502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Revised: 08/11/2022] [Accepted: 09/22/2022] [Indexed: 11/03/2022] Open
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12
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García EA, Blanco FC, Bigi F. H65 fusion protein fails to improve the protection of a rationally attenuated live vaccine candidate against bovine tuberculosis in a mouse model of tuberculosis. Int J Mycobacteriol 2021; 10:411-413. [PMID: 34916460 DOI: 10.4103/ijmy.ijmy_201_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Background The fusion protein H65, composed of Mycobacterium tuberculosis (TB) ESX-secreted antigens, has improved the bacillus Calmette-Guerin-induced immune protection in a mouse model of bovine TB when formulated in the liposomal adjuvant CAF01. In this study, we aimed to evaluate the protective efficacy of an attenuated Mycobacterium bovis strain - a mutant in mce2 and phoP genes - combined with H65+CAF01 immunization. We evaluated the protection of MbΔmce2-phoP alone or combined with H65+CAF01 against M. bovis challenge in mice. Methods Groups of BALBc mice were inoculated with the vaccine candidates or phosphate buffered saline (PBS), and 6 weeks after the last immunization, the animals were aerogenically challenged with virulent M. bovis. Bacterial load in organs was counted after 45 days of the challenge. One-way analysis of variance and Bonferroni's posttest were used for statistical analysis. Results All vaccinated mice showed reduced bacterial loads in lungs compared to unvaccinated animals. However, the protection level was similar between vaccinated groups. Conclusions The MbΔmce2-phoP strain combined with three doses of H65+CAF01 induced equivalent protection than the MbΔmce2-phoP strain alone. Thus, the use of combined vaccination strategies requires a careful analysis of the potential interactions of each of their components with the host's immune system.
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Affiliation(s)
- Elizabeth A García
- Instituto de Agrobiotecnologia y Biologia Molecular, Institute of Agrobiotechnology and Molecular Biology, (IABIMO) INTA-CONICET; Laboratorio de Tuberculosis Bovina, Bovine Tuberculosis Laboratory, Instituto de Biotecnología, CICVyA, Instituto Nacional de Tecnología Agropecuaria, Institute of Biotechnology, National Institute of Agricultural Technology, Buenos Aires, Argentina
| | - Federico C Blanco
- Instituto de Agrobiotecnologia y Biologia Molecular, Institute of Agrobiotechnology and Molecular Biology, (IABIMO) INTA-CONICET; Laboratorio de Tuberculosis Bovina, Bovine Tuberculosis Laboratory, Instituto de Biotecnología, CICVyA, Instituto Nacional de Tecnología Agropecuaria, Institute of Biotechnology, National Institute of Agricultural Technology, Buenos Aires, Argentina
| | - Fabiana Bigi
- Instituto de Agrobiotecnologia y Biologia Molecular, Institute of Agrobiotechnology and Molecular Biology, (IABIMO) INTA-CONICET; Laboratorio de Tuberculosis Bovina, Bovine Tuberculosis Laboratory, Instituto de Biotecnología, CICVyA, Instituto Nacional de Tecnología Agropecuaria, Institute of Biotechnology, National Institute of Agricultural Technology, Buenos Aires, Argentina
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13
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Payros D, Alonso H, Malaga W, Volle A, Mazères S, Déjean S, Valière S, Moreau F, Balor S, Stella A, Combes-Soia L, Burlet-Schiltz O, Bouchez O, Nigou J, Astarie-Dequeker C, Guilhot C. Rv0180c contributes to Mycobacterium tuberculosis cell shape and to infectivity in mice and macrophages. PLoS Pathog 2021; 17:e1010020. [PMID: 34724002 PMCID: PMC8584747 DOI: 10.1371/journal.ppat.1010020] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 11/11/2021] [Accepted: 10/08/2021] [Indexed: 11/19/2022] Open
Abstract
Mycobacterium tuberculosis, the main causative agent of human tuberculosis, is transmitted from person to person via small droplets containing very few bacteria. Optimizing the chance to seed in the lungs is therefore a major adaptation to favor survival and dissemination in the human population. Here we used TnSeq to identify genes important for the early events leading to bacterial seeding in the lungs. Beside several genes encoding known virulence factors, we found three new candidates not previously described: rv0180c, rv1779c and rv1592c. We focused on the gene, rv0180c, of unknown function. First, we found that deletion of rv0180c in M. tuberculosis substantially reduced the initiation of infection in the lungs of mice. Next, we established that Rv0180c enhances entry into macrophages through the use of complement-receptor 3 (CR3), a major phagocytic receptor for M. tuberculosis. Silencing CR3 or blocking the CR3 lectin site abolished the difference in entry between the wild-type parental strain and the Δrv0180c::km mutant. However, we detected no difference in the production of both CR3-known carbohydrate ligands (glucan, arabinomannan, mannan), CR3-modulating lipids (phthiocerol dimycocerosate), or proteins in the capsule of the Δrv0180c::km mutant in comparison to the wild-type or complemented strains. By contrast, we established that Rv0180c contributes to the functionality of the bacterial cell envelope regarding resistance to toxic molecule attack and cell shape. This alteration of bacterial shape could impair the engagement of membrane receptors that M. tuberculosis uses to invade host cells, and open a new perspective on the modulation of bacterial infectivity. The epidemic efficiency of tuberculosis bacilli is determined by their capacity to transmit via aerosol. Currently, the bacterial functions that favor Mycobacterium tuberculosis seeding in the lung of naïve host remain mostly unknown. Here we implemented a genome-wide approach to identify M. tuberculosis mutants deficient for seeding and early replication in the lung of mice. In addition to genes known to encode virulence factors, we identified three genes not previously described. We used complementary approaches to characterize the phenotype of a M. tuberculosis mutant with insertion within the rv0180c gene. We found that this mutant is impaired for seeding in the lung of mice and for invasion and replication in human macrophages. In macrophages, the defect relies on a lack of engagement of CR3 receptor. Although we did not detect any difference between the wild type strain and the rv0180c mutant with regard to potential CR3-ligand, we found that the bacterial cell envelope is altered in the rv0180c mutant. Our study provides new insight into bacterial genes required for early interaction of M. tuberculosis with the host and perspective to understand the bacterial functions enhancing infectivity.
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Affiliation(s)
- Delphine Payros
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Henar Alonso
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Wladimir Malaga
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Arnaud Volle
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Serge Mazères
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Sébastien Déjean
- Institut de Mathématiques de Toulouse, UMR5219, Université de Toulouse, CNRS, UPS, Toulouse, France
| | | | - Flavie Moreau
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Stéphanie Balor
- Plateforme de Microscopie Électronique Intégrative (METi), Centre de Biologie Intégrative (CBI), CNRS, Toulouse, France
| | - Alexandre Stella
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Lucie Combes-Soia
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Odile Burlet-Schiltz
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, UPS, Toulouse, France
| | | | - Jérôme Nigou
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Catherine Astarie-Dequeker
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, UPS, Toulouse, France
- * E-mail: (CAD); (CG)
| | - Christophe Guilhot
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, UPS, Toulouse, France
- * E-mail: (CAD); (CG)
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14
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Sarkar S, Dey U, Khohliwe TB, Yella VR, Kumar A. Analysis of nucleoid-associated protein-binding regions reveals DNA structural features influencing genome organization in Mycobacterium tuberculosis. FEBS Lett 2021; 595:2504-2521. [PMID: 34387867 DOI: 10.1002/1873-3468.14178] [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: 06/11/2021] [Revised: 08/01/2021] [Accepted: 08/11/2021] [Indexed: 11/10/2022]
Abstract
Nucleoid-associated proteins (NAPs) maintain bacterial nucleoid configuration through their architectural properties of DNA bending, wrapping, and bridging. However, the contribution of DNA structural alterations to DNA-NAP recognition at the genomic scale remains unresolved. Present work dissects the DNA sequence, shape and altered structural preferences at a genomic scale for six NAPs in Mycobacterium tuberculosis. Results suggest narrower minor groove width (MGW) and higher DNA rigidity are marked for the binding sites of EspR and Lsr2, while mIHF, MtHU and NapM have heterogeneous DNA structural predilections. In contrast, WhiB4-DNA-binding sites were characterized by wider MGW, highly deformable and less curved DNA. This work provides systematic insight into NAP-mediated genome organization as a function of DNA structural features.
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Affiliation(s)
- Sharmilee Sarkar
- Department of Molecular Biology and Biotechnology, Tezpur University, India
| | - Upalabdha Dey
- Department of Molecular Biology and Biotechnology, Tezpur University, India
| | | | - Venkata Rajesh Yella
- Department of Biotechnology, Koneru Lakshmaiah Education Foundation, Guntur, India
| | - Aditya Kumar
- Department of Molecular Biology and Biotechnology, Tezpur University, India
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15
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Sharma S, Sharma M. Proline-Glutamate/Proline-Proline-Glutamate (PE/PPE) proteins of Mycobacterium tuberculosis: The multifaceted immune-modulators. Acta Trop 2021; 222:106035. [PMID: 34224720 DOI: 10.1016/j.actatropica.2021.106035] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 06/23/2021] [Accepted: 06/29/2021] [Indexed: 12/30/2022]
Abstract
The PE/PPE proteins encoded by seven percent (7%) of Mycobacterium tuberculosis (Mtb) genome are the chief constituents to pathogen's virulence reservoir. The fact that these genes have evolved along ESX secretory system in pathogenic Mtb strains make their investigation very intriguing. There is lot of speculation about the prominent role of these proteins at host pathogen interface and in disease pathogenesis. Nevertheless, the exact function of PE/PPE proteins still remains a mystery which calls for further research targeting these proteins. This article is an effort to document all the facts known so far with regard to these unique proteins which involves their origin, evolution, transcriptional control, and most important their role as host immune-modulators. Our understanding strongly points towards the versatile nature of these PE/PPE proteins as Mtb's host immune sensors and as decisive factors in shaping the outcome of infection. Further investigation on these proteins will surely pave way for newer and effective vaccines and therapeutics to control Tuberculosis (TB).
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Affiliation(s)
- Sadhna Sharma
- DS Kothari Central Interdisciplinary Research Centre and Department of Zoology, Miranda House, University of Delhi, Delhi 110007, India.
| | - Monika Sharma
- DS Kothari Central Interdisciplinary Research Centre and Department of Zoology, Miranda House, University of Delhi, Delhi 110007, India.
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16
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Rivera-Calzada A, Famelis N, Llorca O, Geibel S. Type VII secretion systems: structure, functions and transport models. Nat Rev Microbiol 2021; 19:567-584. [PMID: 34040228 DOI: 10.1038/s41579-021-00560-5] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/09/2021] [Indexed: 02/07/2023]
Abstract
Type VII secretion systems (T7SSs) have a key role in the secretion of effector proteins in non-pathogenic mycobacteria and pathogenic mycobacteria such as Mycobacterium tuberculosis, the main causative agent of tuberculosis. Tuberculosis-causing mycobacteria, still accounting for 1.4 million deaths annually, rely on paralogous T7SSs to survive in the host and efficiently evade its immune response. Although it is still unknown how effector proteins of T7SSs cross the outer membrane of the diderm mycobacterial cell envelope, recent advances in the structural characterization of these secretion systems have revealed the intricate network of interactions of conserved components in the plasma membrane. This structural information, added to recent advances in the molecular biology and regulation of mycobacterial T7SSs as well as progress in our understanding of their secreted effector proteins, is shedding light on the inner working of the T7SS machinery. In this Review, we highlight the implications of these studies and the derived transport models, which provide new scenarios for targeting the deathly human pathogen M. tuberculosis.
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Affiliation(s)
- Angel Rivera-Calzada
- Structural Biology Programme, Spanish National Cancer Research Centre (CNIO), Madrid, Spain.
| | - Nikolaos Famelis
- Institute for Molecular Infection Biology, Julius-Maximilian University of Würzburg, Würzburg, Germany.,Rudolf Virchow Center for Integrative and Translational Biomedicine, Julius-Maximilian University of Würzburg, Würzburg, Germany
| | - Oscar Llorca
- Structural Biology Programme, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Sebastian Geibel
- Institute for Molecular Infection Biology, Julius-Maximilian University of Würzburg, Würzburg, Germany. .,Rudolf Virchow Center for Integrative and Translational Biomedicine, Julius-Maximilian University of Würzburg, Würzburg, Germany.
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17
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Shao X, Tan M, Xie Y, Yao C, Wang T, Huang H, Zhang Y, Ding Y, Liu J, Han L, Hua C, Wang X, Deng X. Integrated regulatory network in Pseudomonas syringae reveals dynamics of virulence. Cell Rep 2021; 34:108920. [PMID: 33789108 DOI: 10.1016/j.celrep.2021.108920] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 02/09/2021] [Accepted: 03/09/2021] [Indexed: 02/07/2023] Open
Abstract
Pseudomonas syringae, a Gram-negative plant pathogen, expresses multitudinous transcriptional regulators to control the type III secretion system (T3SS) and response to diverse environmental challenges. Although the mechanisms of virulence-associated regulators of P. syringae have been studied for decades, the overall crosstalk underlying these regulators is still elusive. Here, we identify five T3SS regulators (EnvZ-OmpR, CbrAB2, PhoPQ, PilRS, and MgrA), and find that the two-component systems EnvZ-OmpR and CbrAB2 negatively regulate the T3SS. To elucidate crosstalk between 16 virulence-associated regulators in P. syringae, we map an online intricate network called "PSRnet" (Pseudomonas syringae regulatory network) by combining the differentially expressed genes (DEGs) of these 16 regulators by RNA sequencing (RNA-seq) and their binding loci by chromatin immunoprecipitation sequencing (ChIP-seq). Consequently, we identify 238 and 153 functional genes involved in the T3SS and other virulence-related pathways in KB and MM media, respectively. Our results provide insights into the mechanism of plant infections caused by P. syringae.
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Affiliation(s)
- Xiaolong Shao
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China
| | - Miaomiao Tan
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China
| | - Yingpeng Xie
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China
| | - Chunyan Yao
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China
| | - Tingting Wang
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China
| | - Hao Huang
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China
| | - Yingchao Zhang
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China
| | - Yiqing Ding
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China
| | - Jingui Liu
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China
| | - Liangliang Han
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China
| | - Canfeng Hua
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China
| | - Xin Wang
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China; Shenzhen Research Institute, City University of Hong Kong, Shenzhen 518057, China.
| | - Xin Deng
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China; Shenzhen Research Institute, City University of Hong Kong, Shenzhen 518057, China.
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18
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Rens C, Chao JD, Sexton DL, Tocheva EI, Av-Gay Y. Roles for phthiocerol dimycocerosate lipids in Mycobacterium tuberculosis pathogenesis. MICROBIOLOGY-SGM 2021; 167. [PMID: 33629944 DOI: 10.1099/mic.0.001042] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The success of Mycobacterium tuberculosis as a pathogen is well established: tuberculosis is the leading cause of death by a single infectious agent worldwide. The threat of multi- and extensively drug-resistant bacteria has renewed global concerns about this pathogen and understanding its virulence strategies will be essential in the fight against tuberculosis. The current review will focus on phthiocerol dimycocerosates (PDIMs), a long-known and well-studied group of complex lipids found in the M. tuberculosis cell envelope. Numerous studies show a role for PDIMs in several key steps of M. tuberculosis pathogenesis, with recent studies highlighting its involvement in bacterial virulence, in association with the ESX-1 secretion system. Yet, the mechanisms by which PDIMs help M. tuberculosis to control macrophage phagocytosis, inhibit phagosome acidification and modulate host innate immunity, remain to be fully elucidated.
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Affiliation(s)
- Céline Rens
- Division of Infectious Disease, Department of Medicine, The University of British Columbia, Vancouver, Canada
| | - Joseph D Chao
- Division of Infectious Disease, Department of Medicine, The University of British Columbia, Vancouver, Canada
| | - Danielle L Sexton
- Department of Microbiology & Immunology, The University of British Columbia, Vancouver, Canada
| | - Elitza I Tocheva
- Department of Microbiology & Immunology, The University of British Columbia, Vancouver, Canada
| | - Yossef Av-Gay
- Division of Infectious Disease, Department of Medicine, The University of British Columbia, Vancouver, Canada.,Department of Microbiology & Immunology, The University of British Columbia, Vancouver, Canada
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19
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Fan K, Cao Q, Lan L. Genome-Wide Mapping Reveals Complex Regulatory Activities of BfmR in Pseudomonas aeruginosa. Microorganisms 2021; 9:485. [PMID: 33668961 PMCID: PMC8025907 DOI: 10.3390/microorganisms9030485] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 02/09/2021] [Accepted: 02/22/2021] [Indexed: 01/04/2023] Open
Abstract
BfmR is a response regulator that modulates diverse pathogenic phenotypes and induces an acute-to-chronic virulence switch in Pseudomonas aeruginosa, an important human pathogen causing serious nosocomial infections. However, the mechanisms of action of BfmR remain largely unknown. Here, using chromatin immunoprecipitation followed by high-throughput sequencing (ChIP-seq), we showed that 174 chromosomal regions of P. aeruginosa MPAO1 genome were highly enriched by coimmunoprecipitation with a C-terminal Flag-tagged BfmR. Integration of these data with global transcriptome analyses revealed that 172 genes in 106 predicted transcription units are potential targets for BfmR. We determined that BfmR binds to and modulates the promoter activity of genes encoding transcriptional regulators CzcR, ExsA, and PhoB. Intriguingly, BfmR bound to the promoters of a number of genes belong to either CzcR or PhoB regulon, or both, indicating that CzcRS and PhoBR two-component systems (TCSs) deeply feed into the BfmR-mediated regulatory network. In addition, we demonstrated that phoB is required for BfmR to promote the biofilm formation by P. aeruginosa. These results delineate the direct BfmR regulon and exemplify the complexity of BfmR-mediated regulation of cellular functions in P. aeruginosa.
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Affiliation(s)
- Ke Fan
- University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing 100049, China;
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China;
| | - Qiao Cao
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China;
| | - Lefu Lan
- University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing 100049, China;
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China;
- School of Pharmaceutical Science and Technology, Hangzhou Institute for Advanced Study, UCAS, Hangzhou 310024, China
- NMPA Key Laboratory for Testing Technology of Pharmaceutical Microbiology, Shanghai Institute for Food and Drug Control, Shanghai 201203, China
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20
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Young AT, Carette X, Helmel M, Steen H, Husson RN, Quackenbush J, Platig J. Multi-omic regulatory networks capture downstream effects of kinase inhibition in Mycobacterium tuberculosis. NPJ Syst Biol Appl 2021; 7:8. [PMID: 33514755 PMCID: PMC7846781 DOI: 10.1038/s41540-020-00164-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 12/07/2020] [Indexed: 11/30/2022] Open
Abstract
The ability of Mycobacterium tuberculosis (Mtb) to adapt to diverse stresses in its host environment is crucial for pathogenesis. Two essential Mtb serine/threonine protein kinases, PknA and PknB, regulate cell growth in response to environmental stimuli, but little is known about their downstream effects. By combining RNA-Seq data, following treatment with either an inhibitor of both PknA and PknB or an inactive control, with publicly available ChIP-Seq and protein–protein interaction data for transcription factors, we show that the Mtb transcription factor (TF) regulatory network propagates the effects of kinase inhibition and leads to widespread changes in regulatory programs involved in cell wall integrity, stress response, and energy production, among others. We also observe that changes in TF regulatory activity correlate with kinase-specific phosphorylation of those TFs. In addition to characterizing the downstream regulatory effects of PknA/PknB inhibition, this demonstrates the need for regulatory network approaches that can incorporate signal-driven transcription factor modifications.
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Affiliation(s)
- Albert T Young
- School of Medicine, University of California, San Francisco, USA
| | - Xavier Carette
- Division of Infectious Diseases, Boston Children's Hospital, Boston, USA.,Harvard Medical School, Boston, USA
| | - Michaela Helmel
- Harvard Medical School, Boston, USA.,Department of Pathology, Boston Children's Hospital, Boston, USA
| | - Hanno Steen
- Division of Infectious Diseases, Boston Children's Hospital, Boston, USA.,Harvard Medical School, Boston, USA.,Department of Pathology, Boston Children's Hospital, Boston, USA
| | - Robert N Husson
- Division of Infectious Diseases, Boston Children's Hospital, Boston, USA.,Harvard Medical School, Boston, USA
| | - John Quackenbush
- Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, USA.,Channing Division of Network Medicine, Brigham and Women's Hospital, Boston, USA
| | - John Platig
- Harvard Medical School, Boston, USA. .,Channing Division of Network Medicine, Brigham and Women's Hospital, Boston, USA.
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21
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Abstract
A vast array of molecular biology tools have been developed to investigate the Mycobacterium tuberculosis genome since the advent of its successful sequencing in 1998. These tools, such as quantitative and end point polymerase chain reaction, chromatin immunoprecipitation, and whole genome sequencing, require genomic DNA extracted from lysed mycobacteria. There are numerous methods described in the literature using mechanical, enzymatic, or chemical means to lyse cells and extract genomic DNA to varying degrees of purity. Here, we describe appropriate methods for genomic DNA isolation from solid or liquid cultures from both M. tuberculosis and nontuberculous mycobacteria.
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Affiliation(s)
- Heena Jagatia
- Department of Respiratory Sciences, University of Leicester, Leicester, UK.
| | - Daire Cantillon
- Department of Global Health and Infection, Brighton and Sussex Medical School, University of Sussex, Brighton, UK
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22
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García EA, Blanco FC, Klepp LI, Pazos A, McNeil MR, Jackson M, Bigi F. Role of PhoPR in the response to stress of Mycobacterium bovis. Comp Immunol Microbiol Infect Dis 2020; 74:101593. [PMID: 33285386 DOI: 10.1016/j.cimid.2020.101593] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 11/16/2020] [Accepted: 11/17/2020] [Indexed: 11/28/2022]
Abstract
PhoP is part of the two-component PhoPR system that regulates the expression of virulence genes of Mycobacteria. The goal of this work was to elucidate the role of PhoP in the mechanism that Mycobacterium bovis, the causative agent of bovine tuberculosis, displays upon stress. An analysis of gene expression and acidic growth curves indicated that M. bovis neutralized the external acidic environment by inducing and secreting ammonia. We found that PhoP is essential for ammonia production/secretion and its role in this process seems to be the induction of asparaginase and urease expression. We also demonstrated that the lack of PhoP negatively affected the synthesis of phthiocerol dimycocerosates. This finding is consistent with the role of the lipid anabolism in maintaining the redox environment upon stress in mycobacteria. Altogether the results of this study indicate that PhoP plays an important role in the response mechanisms to stress of M. bovis.
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Affiliation(s)
- Elizabeth A García
- Instituto de Agrobiotecnología y Biología Molecular, (IABIMO) INTA-CONICET, Argentina; Instituto de Biotecnología, CICVyA, Instituto Nacional de Tecnología Agropecuaria Institute of Biotechnology, National Institute of Agricultural Technology, Argentina.
| | - Federico C Blanco
- Instituto de Agrobiotecnología y Biología Molecular, (IABIMO) INTA-CONICET, Argentina; Instituto de Biotecnología, CICVyA, Instituto Nacional de Tecnología Agropecuaria Institute of Biotechnology, National Institute of Agricultural Technology, Argentina.
| | - Laura I Klepp
- Instituto de Agrobiotecnología y Biología Molecular, (IABIMO) INTA-CONICET, Argentina; Instituto de Biotecnología, CICVyA, Instituto Nacional de Tecnología Agropecuaria Institute of Biotechnology, National Institute of Agricultural Technology, Argentina.
| | - Adriana Pazos
- Instituto Tecnología de Alimentos (ITA), INTA, Food Technology Institute, Argentina.
| | - Michael R McNeil
- Colorado State University, Dept. of Microbiology, Immunology and Pathology, USA.
| | - Mary Jackson
- Colorado State University, Dept. of Microbiology, Immunology and Pathology, USA.
| | - Fabiana Bigi
- Instituto de Agrobiotecnología y Biología Molecular, (IABIMO) INTA-CONICET, Argentina; Instituto de Biotecnología, CICVyA, Instituto Nacional de Tecnología Agropecuaria Institute of Biotechnology, National Institute of Agricultural Technology, Argentina.
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23
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Modeling Tubercular ESX-1 Secretion Using Mycobacterium marinum. Microbiol Mol Biol Rev 2020; 84:84/4/e00082-19. [DOI: 10.1128/mmbr.00082-19] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Pathogenic mycobacteria cause chronic and acute diseases ranging from human tuberculosis (TB) to nontubercular infections.
Mycobacterium tuberculosis
causes both acute and chronic human tuberculosis. Environmentally acquired nontubercular mycobacteria (NTM) cause chronic disease in humans and animals. Not surprisingly, NTM and
M. tuberculosis
often use shared molecular mechanisms to survive within the host. The ESX-1 system is a specialized secretion system that is essential for virulence and is functionally conserved between
M. tuberculosis
and
Mycobacterium marinum
.
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24
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Conserved ESX-1 Substrates EspE and EspF Are Virulence Factors That Regulate Gene Expression. Infect Immun 2020; 88:IAI.00289-20. [PMID: 32900815 DOI: 10.1128/iai.00289-20] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 08/28/2020] [Indexed: 12/12/2022] Open
Abstract
Mycobacterium tuberculosis, the cause of human tuberculosis, and Mycobacterium marinum, a nontubercular pathogen with a broad host range, require the ESX-1 secretion system for virulence. The ESX-1 system secretes proteins which cause phagosomal lysis within the macrophage via an unknown mechanism. As reported elsewhere (R. E. Bosserman et al., Proc Natl Acad Sci U S A 114:E10772-E10781, 2017, https://doi.org/10.1073/pnas.1710167114), we recently discovered that the ESX-1 system regulates gene expression in M. marinum This finding was confirmed in M. tuberculosis in reports by C. Sala et al. (PLoS Pathog 14:e1007491, 2018, https://doi.org/10.1371/journal.ppat.1007491) and A. M. Abdallah et al. (PLoS One 14:e0211003, 2019, https://doi.org/10.1371/journal.pone.0211003). We further demonstrated that a feedback control mechanism connects protein secretion to WhiB6-dependent expression of the esx-1 genes via an unknown mechanism. Here, we connect protein secretion and gene expression by showing for the first time that specific ESX-1 substrates have dual functions inside and outside the mycobacterial cell. We demonstrate that the EspE and EspF substrates negatively control esx-1 gene expression in the M. marinum cytoplasm through the conserved WhiB6 transcription factor. We found that EspE and EspF are required for virulence and promote lytic activity independently of the major EsxA and EsxB substrates. We show that the dual functions of EspE and EspF are conserved in the orthologous proteins from M. tuberculosis Our findings support a role for EspE and EspF in virulence that is independent of the EsxA and EsxB substrates and demonstrate that ESX-1 substrates have a conserved role in regulating gene expression.
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25
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Li X, Ren F, Cai G, Huang P, Chai Q, Gundogdu O, Jiao X, Huang J. Investigating the Role of FlhF Identifies Novel Interactions With Genes Involved in Flagellar Synthesis in Campylobacter jejuni. Front Microbiol 2020; 11:460. [PMID: 32265885 PMCID: PMC7105676 DOI: 10.3389/fmicb.2020.00460] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2019] [Accepted: 03/04/2020] [Indexed: 12/15/2022] Open
Abstract
FlhF is a key protein required for complete flagellar synthesis, and its deletion results in the complete absence of a flagella and thus motility in Campylobacter jejuni. However, the specific mechanism still remains unknown. In this study, RNA-Seq, EMSAs, ChIP-qPCR and β-Galactosidase assays were performed to elucidate the novel interactions between FlhF and genes involved in flagellar synthesis. Results showed that FlhF has an overall influence on the transcription of flagellar genes with an flhF mutant displaying down-regulation of most flagellar related genes. FlhF can directly bind to the flgI promoter to regulate its expression, which has significant expression change in an flhF mutant. The possible binding site of FlhF to the flgI promoter was explored by continuously narrowing the flgI promoter region and performing further point mutations. Meanwhile, FlhF can directly bind to the promoters of rpoD, flgS, and fliA encoding early flagellin regulators, thereby directly or indirectly regulating the synthesis of class I, II, and III flagellar genes, respectively. Collectively, this study demonstrates that FlhF may directly regulate the transcription of flagellar genes by binding to their promoters as a transcriptional regulator, which will be helpful in understanding the mechanism of FlhF in flagellar biosynthetic and bacterial flagellation in general.
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Affiliation(s)
- Xiaofei Li
- Jiangsu Key Laboratory of Zoonosis, Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, China
| | - Fangzhe Ren
- Jiangsu Key Laboratory of Zoonosis, Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, China
| | - Guoqiang Cai
- Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of Agriculture of China, Yangzhou, China
| | - Pingyu Huang
- Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of Agriculture of China, Yangzhou, China
| | - Qinwen Chai
- Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of Agriculture of China, Yangzhou, China
| | - Ozan Gundogdu
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Xinan Jiao
- Joint International Research Laboratory of Agriculture and Agri-product Safety, Ministry of Education of China, Yangzhou, China
| | - Jinlin Huang
- Joint International Research Laboratory of Agriculture and Agri-product Safety, Ministry of Education of China, Yangzhou, China
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26
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Intelligent Mechanisms of Macrophage Apoptosis Subversion by Mycobacterium. Pathogens 2020; 9:pathogens9030218. [PMID: 32188164 PMCID: PMC7157668 DOI: 10.3390/pathogens9030218] [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: 02/25/2020] [Revised: 03/12/2020] [Accepted: 03/15/2020] [Indexed: 02/07/2023] Open
Abstract
Macrophages are one of the first innate defense barriers and play an indispensable role in communication between innate and adaptive immune responses, leading to restricted Mycobacterium tuberculosis (Mtb) infection. The macrophages can undergo programmed cell death (apoptosis), which is a crucial step to limit the intracellular growth of bacilli by liberating them into extracellular milieu in the form of apoptotic bodies. These bodies can be taken up by the macrophages for the further degradation of bacilli or by the dendritic cells, thereby leading to the activation of T lymphocytes. However, Mtb has the ability to interplay with complex signaling networks to subvert macrophage apoptosis. Here, we describe the intelligent strategies of Mtb inhibition of macrophages apoptosis. This review provides a platform for the future study of unrevealed Mtb anti-apoptotic mechanisms and the design of therapeutic interventions.
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27
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Structural and DNA binding properties of mycobacterial integration host factor mIHF. J Struct Biol 2020; 209:107434. [PMID: 31846718 DOI: 10.1016/j.jsb.2019.107434] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 12/06/2019] [Accepted: 12/11/2019] [Indexed: 01/08/2023]
Abstract
In bacteria, nucleoid associated proteins (NAPs) take part in active chromosome organization by supercoil management, three-dimensional DNA looping and direct transcriptional control. Mycobacterial integration host factor (mIHF, rv1388) is a NAP restricted to Actinobacteria and essential for survival of the human pathogen Mycobacterium tuberculosis. We show in vitro that DNA binding by mIHF strongly stabilizes the protein and increases its melting temperature. The structure obtained by Nuclear Magnetic Resonance (NMR) spectroscopy characterizes mIHF as a globular protein with a protruding alpha helix and a disordered N-terminus, similar to Streptomyces coelicolor IHF (sIHF). NMR revealed no residues of high flexibility, suggesting that mIHF is a rigid protein overall that does not undergo structural rearrangements. We show that mIHF only binds to double stranded DNA in solution, through two DNA binding sites (DBSs) similar to those identified in the X-ray structure of sIHF. According to Atomic Force Microscopy, mIHF is able to introduce left-handed loops of ca. 100 nm size (~300 bp) in supercoiled cosmids, thereby unwinding and relaxing the DNA.
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28
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Mai J, Rao C, Watt J, Sun X, Lin C, Zhang L, Liu J. Mycobacterium tuberculosis 6C sRNA binds multiple mRNA targets via C-rich loops independent of RNA chaperones. Nucleic Acids Res 2019; 47:4292-4307. [PMID: 30820540 PMCID: PMC6486639 DOI: 10.1093/nar/gkz149] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 02/19/2019] [Accepted: 02/22/2019] [Indexed: 12/15/2022] Open
Abstract
Bacterial small regulatory RNAs (sRNAs) are the most abundant class of post-transcriptional regulators and have been well studied in Gram-negative bacteria. Little is known about the functions and mechanisms of sRNAs in high GC Gram-positive bacteria including Mycobacterium and Streptomyces. Here, we performed an in-depth study of 6C sRNA of Mycobacterium tuberculosis, which is conserved among high GC Gram-positive bacteria. Forty-seven genes were identified as possible direct targets of 6C sRNA and 15 of them were validated using an in vivo translational lacZ fusion system. We found that 6C sRNA plays a pleotropic role and regulates genes involved in various cellular processes, including DNA replication and protein secretion. Mapping the interactions of 6C sRNA with mRNA targets panD and dnaB revealed that the C-rich loops of 6C sRNA act as direct binding sites to mRNA targets. Unlike in Gram-negative bacteria where RNA binding proteins Hfq and ProQ are required, the interactions of 6C sRNA with mRNAs appear to be independent of RNA chaperones. Our findings suggest that the multiple G–C pairings between single stranded regions are sufficient to establish stable interactions between 6C sRNA and mRNA targets, providing a mechanism for sRNAs in high GC Gram-positive bacteria.
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Affiliation(s)
- Juntao Mai
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Chitong Rao
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Jacqueline Watt
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Xian Sun
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Science, Fudan University, Shanghai, China
| | - Chen Lin
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Science, Fudan University, Shanghai, China
| | - Lu Zhang
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Science, Fudan University, Shanghai, China.,Shanghai Engineering Research Center of Industrial Microorganisms, Shanghai, China
| | - Jun Liu
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
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29
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An integrated genomic regulatory network of virulence-related transcriptional factors in Pseudomonas aeruginosa. Nat Commun 2019; 10:2931. [PMID: 31270321 PMCID: PMC6610081 DOI: 10.1038/s41467-019-10778-w] [Citation(s) in RCA: 91] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Accepted: 05/30/2019] [Indexed: 01/12/2023] Open
Abstract
The virulence of Pseudomonas aeruginosa, a Gram-negative opportunistic pathogen, is regulated by many transcriptional factors (TFs) that control the expression of quorum sensing and protein secretion systems. Here, we report a genome-wide, network-based approach to dissect the crosstalk between 20 key virulence-related TFs. Using chromatin immunoprecipitation coupled with high-throughput sequencing (ChIP-seq), as well as RNA-seq, we identify 1200 TF-bound genes and 4775 differentially expressed genes. We experimentally validate 347 of these genes as functional target genes, and describe the regulatory relationships of the 20 TFs with their targets in a network that we call ‘Pseudomonas aeruginosa genomic regulatory network’ (PAGnet). Analysis of the network led to the identification of novel functions for two TFs (ExsA and GacA) in quorum sensing and nitrogen metabolism. Furthermore, we present an online platform and R package based on PAGnet to facilitate updating and user-customised analyses. The virulence of Pseudomonas aeruginosa is regulated by many transcriptional factors (TFs). Here, the authors study the crosstalk between 20 key virulence-related TFs, validate 347 functional target genes, and describe the regulatory relationships of the 20 TFs with their targets in a network that is available as an online platform.
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30
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Zeng S, Constant P, Yang D, Baulard A, Lefèvre P, Daffé M, Wattiez R, Fontaine V. Cpn60.1 (GroEL1) Contributes to Mycobacterial Crabtree Effect: Implications for Biofilm Formation. Front Microbiol 2019; 10:1149. [PMID: 31244785 PMCID: PMC6579834 DOI: 10.3389/fmicb.2019.01149] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 05/06/2019] [Indexed: 12/18/2022] Open
Abstract
Biofilm formation is a survival strategy for microorganisms facing a hostile environment. Under biofilm, bacteria are better protected against antibacterial drugs and the immune response, increasing treatment difficulty, as persistent populations recalcitrant to chemotherapy are promoted. Deciphering mechanisms leading to biofilms could, thus, be beneficial to obtain new antibacterial drug candidates. Here, we show that mycobacterial biofilm formation is linked to excess glycerol adaptation and the concomitant establishment of the Crabtree effect. This effect is characterized by respiratory reprogramming, ATP downregulation, and secretion of various metabolites including pyruvate, acetate, succinate, and glutamate. Interestingly, the Crabtree effect was abnormal in a mycobacterial strain deficient for Cpn60.1 (GroEL1). Indeed, this mutant strain had a compromised ability to downregulate ATP and secreted more pyruvate, acetate, succinate, and glutamate in the culture medium. Importantly, the mutant strain had higher intracellular pyruvate and produced more toxic methylglyoxal, suggesting a glycolytic stress leading to growth stasis and consequently biofilm failure. This study demonstrates, for the first time, the link between mycobacterial biofilm formation and the Crabtree effect.
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Affiliation(s)
- Sheng Zeng
- Microbiology, Bioorganic and Macromolecular Chemistry Research Unit, Faculté de Pharmacie, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Patricia Constant
- Department of Tuberculosis and Infection Biology, Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Dong Yang
- Microbiology, Bioorganic and Macromolecular Chemistry Research Unit, Faculté de Pharmacie, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Alain Baulard
- Institut Pasteur de Lille, Université de Lille, CNRS, INSERM, CHU Lille, U1019-UMR 8204, Center for Infection and Immunity of Lille, Lille, France
| | - Philippe Lefèvre
- Microbiology, Bioorganic and Macromolecular Chemistry Research Unit, Faculté de Pharmacie, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Mamadou Daffé
- Department of Tuberculosis and Infection Biology, Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Ruddy Wattiez
- Department of Proteomics and Microbiology, University of Mons, Mons, Belgium
| | - Véronique Fontaine
- Microbiology, Bioorganic and Macromolecular Chemistry Research Unit, Faculté de Pharmacie, Université Libre de Bruxelles (ULB), Brussels, Belgium
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31
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Nontuberculous Mycobacteria Persistence in a Cell Model Mimicking Alveolar Macrophages. Microorganisms 2019; 7:microorganisms7050113. [PMID: 31035520 PMCID: PMC6560506 DOI: 10.3390/microorganisms7050113] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Revised: 04/22/2019] [Accepted: 04/24/2019] [Indexed: 12/15/2022] Open
Abstract
Nontuberculous Mycobacteria (NTM) respiratory infections have been gradually increasing. Here, THP-1 cells were used as a model to evaluate intracellular persistence of three NTM species (reference and clinical strains) in human alveolar macrophages. The contribution of phagosome acidification, nitric oxide (NO) production and cell dead on NTM intracellular fate was assessed. In addition, strains were characterized regarding their repertoire of virulence factors by whole-genome sequencing. NTM experienced different intracellular fates: M. smegmatis and M. fortuitum ATCC 6841 were cleared within 24h. In contrast, M. avium strains (reference/clinical) and M. fortuitum clinical strain were able to replicate. Despite this fact, unexpectedly high percentages of acidified phagosomes were found harbouring rab7, but not CD63. All NTM were able to survive in vitro at acidic pHs, with the exception of M. smegmatis. Our data further suggested a minor role for NO in intracellular persistence and that apoptosis mediated by caspase 8 and 3/7, but not necrosis, is triggered during NTM infection. Insights regarding the bacteria genomic backbone corroborated the virulence potential of M. avium and M. fortuitum. In conclusion, the phenotypic traits detected contrast with those described for M. tuberculosis, pointing out that NTM adopt distinct strategies to manipulate the host immune defense and persist intracellularly.
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32
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Jin C, Wu X, Dong C, Li F, Fan L, Xiong S, Dong Y. EspR promotes mycobacteria survival in macrophages by inhibiting MyD88 mediated inflammation and apoptosis. Tuberculosis (Edinb) 2019; 116:22-31. [PMID: 31153514 DOI: 10.1016/j.tube.2019.03.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 02/18/2019] [Accepted: 03/30/2019] [Indexed: 12/22/2022]
Abstract
Tuberculosis is an infectious disease caused by Mycobacterium tuberculosis (Mtb), leading to about a million deaths each year. EspR is a DNA binding protein of Mtb which regulates expression of multiple genes and the activity of ESX-1 secretion system of the bacteria, with itself being secreted out as a substrate of ESX-1. We explored the function of secreted EspR in host cells by overexpressing the protein in murine macrophage cell line RAW264.7, infecting the cells with BCG which does not secrete EspR, and evaluating the antimicrobial responses of the cells. We found that EspR resulted in an increased intracellular bacteria load in macrophages. This is due to its inhibition on BCG induced expression of inflammatory cytokines and inducible nitric oxide synthase (iNOS), as well as host cell apoptosis. Mechanism study showed that EspR directly interacted with adaptor protein myeloid differentiation factor 88 (MyD88), suppressed MyD88 dependent Toll-like receptor (TLR) and IL-1R signal activation, thus reduced inflammatory responses and apoptosis in macrophages and promoted mycobacteria survival.
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Affiliation(s)
- Chunyan Jin
- Jiangsu Key Laboratory of Infection and Immunity, Institute of Biology and Medical Sciences, Soochow University, Postal address: 199 Renai Road, SIP, Suzhou, Jiangsu, China.
| | - Xiaoyu Wu
- Jiangsu Key Laboratory of Infection and Immunity, Institute of Biology and Medical Sciences, Soochow University, Postal address: 199 Renai Road, SIP, Suzhou, Jiangsu, China.
| | - Chunsheng Dong
- Jiangsu Key Laboratory of Infection and Immunity, Institute of Biology and Medical Sciences, Soochow University, Postal address: 199 Renai Road, SIP, Suzhou, Jiangsu, China.
| | - Fengge Li
- Jiangsu Key Laboratory of Infection and Immunity, Institute of Biology and Medical Sciences, Soochow University, Postal address: 199 Renai Road, SIP, Suzhou, Jiangsu, China.
| | - Lingbo Fan
- Jiangsu Key Laboratory of Infection and Immunity, Institute of Biology and Medical Sciences, Soochow University, Postal address: 199 Renai Road, SIP, Suzhou, Jiangsu, China.
| | - Sidong Xiong
- Jiangsu Key Laboratory of Infection and Immunity, Institute of Biology and Medical Sciences, Soochow University, Postal address: 199 Renai Road, SIP, Suzhou, Jiangsu, China.
| | - Yuanshu Dong
- Jiangsu Key Laboratory of Infection and Immunity, Institute of Biology and Medical Sciences, Soochow University, Postal address: 199 Renai Road, SIP, Suzhou, Jiangsu, China.
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33
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NapA (Rv0430), a Novel Nucleoid-Associated Protein that Regulates a Virulence Operon in Mycobacterium tuberculosis in a Supercoiling-Dependent Manner. J Mol Biol 2019; 431:1576-1591. [DOI: 10.1016/j.jmb.2019.02.029] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2018] [Revised: 02/23/2019] [Accepted: 02/25/2019] [Indexed: 12/17/2022]
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34
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Pseudomonas savastanoi Two-Component System RhpRS Switches between Virulence and Metabolism by Tuning Phosphorylation State and Sensing Nutritional Conditions. mBio 2019; 10:mBio.02838-18. [PMID: 30890603 PMCID: PMC6426608 DOI: 10.1128/mbio.02838-18] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pseudomonas savastanoi uses a type III secretion system (T3SS) to invade host plants. Our previous studies have demonstrated that a two-component system (TCS), RhpRS, enables P. savastanoi to coordinate the T3SS gene expression, which depends on the phosphorylation state of RhpR under different environmental conditions. Orthologues of RhpRS are distributed in a wide range of bacterial species, indicating a general regulatory mechanism. How RhpRS uses external signals and the phosphorylation state to exercise its regulatory functions remains unknown. We performed chromatin immunoprecipitation sequencing (ChIP-seq) assays to identify the specific binding sites of RhpR and RhpRD70A in either King's B medium (KB [a T3SS-inhibiting medium]) or minimal medium (MM [a T3SS-inducing medium]). We identified 125 KB-dependent binding sites and 188 phosphorylation-dependent binding sites of RhpR. In KB, RhpR directly and positively regulated cytochrome c 550 production (via ccmA) and alcohol dehydrogenase activity (via adhB) but negatively regulated anthranilate synthase activity (via trpG) and protease activity (via hemB). In addition, phosphorylated RhpR (RhpR-P) directly and negatively regulated the T3SS (via hrpR and hopR1), swimming motility (via flhA), c-di-GMP levels (via PSPPH_2590), and biofilm formation (via algD). It positively regulated twitching motility (via fimA) and lipopolysaccharide production (via PSPPH_2653). Our transcriptome sequencing (RNA-seq) analyses identified 474 and 840 new genes that were regulated by RhpR in KB and MM, respectively. We showed nutrient-rich conditions allowed RhpR to directly regulate multiple metabolic pathways of P. savastanoi and phosphorylation enabled RhpR to specifically control virulence and the cell envelope. The action of RhpRS switched between virulence and regulation of multiple metabolic pathways by tuning its phosphorylation and sensing environmental signals in KB, respectively.IMPORTANCE The plant pathogen Pseudomonas savastanoi invades host plants through a type III secretion system, which is strictly regulated by a two-component system called RhpRS. The orthologues of RhpRS are widely distributed in the bacterial kingdom. The master regulator RhpR specifically depends on the phosphorylation state to regulate the majority of the virulence-related genes. Under nutrient-rich conditions, it modulates many important metabolic pathways, which consist of one-fifth of the genome. We propose that RhpRS uses phosphorylation- and nutrition-dependent mechanisms to switch between regulating virulence and metabolism, and this functionality is widely conserved among bacterial species.
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35
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Datta C, Jha RK, Ahmed W, Ganguly S, Ghosh S, Nagaraja V. Physical and functional interaction between nucleoid-associated proteins HU and Lsr2 of Mycobacterium tuberculosis: altered DNA binding and gene regulation. Mol Microbiol 2019; 111:981-994. [PMID: 30633392 DOI: 10.1111/mmi.14202] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/06/2019] [Indexed: 12/15/2022]
Abstract
Nucleoid-associated proteins (NAPs) in bacteria contribute to key activities such as DNA compaction, chromosome organization and regulation of gene expression. HU and Lsr2 are two principal NAPs in Mycobacterium tuberculosis (Mtb). HU is essential for Mtb survival and is one of the most abundant NAPs. It differs from other eubacterial HU proteins in having a long, flexible lysine- and arginine-rich carboxy-terminal domain. Lsr2 of Mtb is the functional analogue of the bacterial NAP commonly called H-NS. Lsr2 binds to and regulates expression of A/T-rich portions of the otherwise G/C-rich mycobacterial chromosome. Here, we demonstrate that HU and Lsr2 interact to form a complex. The interaction occurs primarily through the flexible carboxy-terminal domain of HU and the acidic amino-terminal domain of Lsr2. The resulting complex, upon binding to DNA, forms thick nucleoprotein rods, in contrast to the DNA bridging seen with Lsr2 and the DNA compaction seen with HU. Furthermore, transcription assays indicate that the HU-Lsr2 complex is a regulator of gene expression. This physical and functional interaction between two NAPs, which has not been reported previously, is likely to be important for DNA organization and gene expression in Mtb and perhaps other bacterial species.
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Affiliation(s)
- Chandreyee Datta
- Department of Microbiology and Cell Biology, Indian Institute of Science, C.V. Raman Avenue, Bangalore, 560012, India
| | - Rajiv Kumar Jha
- Department of Microbiology and Cell Biology, Indian Institute of Science, C.V. Raman Avenue, Bangalore, 560012, India
| | - Wareed Ahmed
- Department of Microbiology and Cell Biology, Indian Institute of Science, C.V. Raman Avenue, Bangalore, 560012, India
| | - Sohini Ganguly
- Department of Microbiology and Cell Biology, Indian Institute of Science, C.V. Raman Avenue, Bangalore, 560012, India
| | - Soumitra Ghosh
- Department of Microbiology and Cell Biology, Indian Institute of Science, C.V. Raman Avenue, Bangalore, 560012, India
| | - Valakunja Nagaraja
- Department of Microbiology and Cell Biology, Indian Institute of Science, C.V. Raman Avenue, Bangalore, 560012, India.,Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, 560064, India
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Sala C, Odermatt NT, Soler-Arnedo P, Gülen MF, von Schultz S, Benjak A, Cole ST. EspL is essential for virulence and stabilizes EspE, EspF and EspH levels in Mycobacterium tuberculosis. PLoS Pathog 2018; 14:e1007491. [PMID: 30571761 PMCID: PMC6319747 DOI: 10.1371/journal.ppat.1007491] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 01/04/2019] [Accepted: 11/28/2018] [Indexed: 12/03/2022] Open
Abstract
The ESX-1, type VII, secretion system represents the major virulence determinant of Mycobacterium tuberculosis, one of the most successful intracellular pathogens. Here, by combining genetic and high-throughput approaches, we show that EspL, a protein of 115 amino acids, is essential for mediating ESX-1-dependent virulence and for stabilization of EspE, EspF and EspH protein levels. Indeed, an espL knock-out mutant was unable to replicate intracellularly, secrete ESX-1 substrates or stimulate innate cytokine production. Moreover, proteomic studies detected greatly reduced amounts of EspE, EspF and EspH in the espL mutant as compared to the wild type strain, suggesting a role for EspL as a chaperone. The latter conclusion was further supported by discovering that EspL interacts with EspD, which was previously demonstrated to stabilize the ESX-1 substrates and effector proteins, EspA and EspC. Loss of EspL also leads to downregulation in M. tuberculosis of WhiB6, a redox-sensitive transcriptional activator of ESX-1 genes. Overall, our data highlight the importance of a so-far overlooked, though conserved, component of the ESX-1 secretion system and begin to delineate the role played by EspE, EspF and EspH in virulence and host-pathogen interaction. Mycobacterium tuberculosis is the etiological agent of human tuberculosis, a life-threatening disease which has seen a recrudescence in the last decades due to the spread of drug-resistant bacterial strains and to co-morbidities such as HIV and diabetes. To develop effective treatment and limit bacterial dissemination within and outside the host, it is pivotal to improve our understanding of the strategies used by the pathogen to colonize the host and subvert the immune defenses. The ESX-1 secretion system represents a key player in these processes. Here we show that the EspL protein, encoded by the ESX-1 gene cluster, is essential for bacterial virulence and for stabilizing the abundance of the EspE, EspF and EspH components of the ESX-1 system. Tubercle bacilli lacking EspL cannot multiply inside macrophages, do not secrete the major virulence factor EsxA and fail to trigger the ESX-1 dependent innate immune response. EspL is thus an important but so-far neglected contributor to ESX-1 function.
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Affiliation(s)
- Claudia Sala
- Global Health Institute, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
- * E-mail: (CS); (STC)
| | - Nina T. Odermatt
- Global Health Institute, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Paloma Soler-Arnedo
- Global Health Institute, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Muhammet F. Gülen
- Global Health Institute, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Sofia von Schultz
- Global Health Institute, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Andrej Benjak
- Global Health Institute, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Stewart T. Cole
- Global Health Institute, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
- * E-mail: (CS); (STC)
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Wang J, Shao X, Zhang Y, Zhu Y, Yang P, Yuan J, Wang T, Yin C, Wang W, Chen S, Liang H, Deng X. HrpS Is a Global Regulator on Type III Secretion System (T3SS) and Non-T3SS Genes in Pseudomonas savastanoi pv. phaseolicola. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2018; 31:1232-1243. [PMID: 29717915 DOI: 10.1094/mpmi-02-18-0035-r] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The type III secretion system (T3SS) is the main machinery for Pseudomonas savastanoi and other gram-negative bacteria to invade plant cells. HrpR and HrpS form a hetero-hexamer, which activates the expression of HrpL, which induces all T3SS genes by binding to a 'hrp box' in promoters. However, the individual molecular mechanism of HrpR or HrpS has not been fully understood. Through chromatin immunoprecipitation coupled to high-throughput DNA sequencing, we found that HrpR, HrpS, and HrpL had four, 47, and 31 targets on the genome, respectively. HrpS directly bound to the promoter regions of a group of T3SS genes and non-T3SS genes. HrpS independently regulated these genes in a hrpL deletion strain. Additionally, a HrpS-binding motif (GTGCCAAA) was identified, which was verified by electrophoretic mobility shift assay and lux-reporter assay. HrpS also regulated motility and biofilm formation in P. savastanoi. The present study strongly suggests that HrpS alone can work as a global regulator on both T3SS and non-T3SS genes in P. savastanoi. [Formula: see text] Copyright © 2018 The Author(s). This is an open-access article distributed under the CC BY-NC-ND 4.0 International license .
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Affiliation(s)
- Jingru Wang
- 1 Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, TEDA Institute of Biological Sciences and Biotechnology, Nankai University, 23 Hongda Street, Tianjin, 300457, China
| | - Xiaolong Shao
- 1 Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, TEDA Institute of Biological Sciences and Biotechnology, Nankai University, 23 Hongda Street, Tianjin, 300457, China
| | - Yingchao Zhang
- 1 Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, TEDA Institute of Biological Sciences and Biotechnology, Nankai University, 23 Hongda Street, Tianjin, 300457, China
| | - Yanan Zhu
- 2 Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, U.S.A
| | - Pan Yang
- 1 Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, TEDA Institute of Biological Sciences and Biotechnology, Nankai University, 23 Hongda Street, Tianjin, 300457, China
| | - Jian Yuan
- 1 Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, TEDA Institute of Biological Sciences and Biotechnology, Nankai University, 23 Hongda Street, Tianjin, 300457, China
| | - Tingting Wang
- 3 Department of Biomedical Sciences, City University of Hong Kong, 83 Tat Chee Rd, Kowloon Tong, Hong Kong
| | - Chunyan Yin
- 1 Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, TEDA Institute of Biological Sciences and Biotechnology, Nankai University, 23 Hongda Street, Tianjin, 300457, China
| | - Wei Wang
- 1 Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, TEDA Institute of Biological Sciences and Biotechnology, Nankai University, 23 Hongda Street, Tianjin, 300457, China
| | - Sheng Chen
- 4 Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Hong Kong; and
| | - Haihua Liang
- 5 Key Laboratory of Resources Biology and Biotechnology in Western China, Ministry of Education, College of Life Science, Northwest University, Xi'an, ShaanXi 710069, China
| | - Xin Deng
- 3 Department of Biomedical Sciences, City University of Hong Kong, 83 Tat Chee Rd, Kowloon Tong, Hong Kong
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38
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Li W, Deng W, Xie J. Expression and regulatory networks of Mycobacterium tuberculosis PE/PPE family antigens. J Cell Physiol 2018; 234:7742-7751. [PMID: 30478834 DOI: 10.1002/jcp.27608] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 09/21/2018] [Indexed: 01/06/2023]
Abstract
PE/PPE family antigens are distributed mainly in pathogenic mycobacteria and serve as potential antituberculosis (TB) vaccine components. Some PE/PPE family antigens can regulate the host innate immune response, interfere with macrophage activation and phagolysosome fusion, and serve as major sources of antigenic variation. PE/PPE antigens have been associated with mycobacteria pathogenesis; pe/ppe genes are mainly found in pathogenic mycobacteria and are differentially expressed between Mtb and Mycobacterium bovis. PE/PPE proteins were essential for the growth of Mtb, and PE/PPE proteins were differentially expressed under a variety of conditions. Multiple mycobacterial-virulence-related transcription factors, sigma factors, the global transcriptional regulation factor Lsr2, MprAB, and PhoPR two-component regulatory systems, and cyclic adenine monophosphate-dependent regulators, regulate the expression of PE/PPE family antigens. Multiple-scale integrative analysis revealed the expression and regulatory networks of PE/PPE family antigens underlying the virulence and pathogenesis of Mtb, providing important clues for the discovery of new anti-TB measures.
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Affiliation(s)
- Wu Li
- Key Laboratory of Regional Characteristic Agricultural Resources, College of Life Sciences, Neijiang Normal University, Neijiang, China
| | - Wanyan Deng
- Key Laboratory of Molecular Biology for Infectious Diseases (Ministry of Education), Institute for Viral Hepatitis, Department of Infectious Diseases, The Second Affiliated Hospital, Chongqing Medical University, Chongqing, China
| | - Jianping Xie
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Beibei, Chongqing, China
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39
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Essential Nucleoid Associated Protein mIHF (Rv1388) Controls Virulence and Housekeeping Genes in Mycobacterium tuberculosis. Sci Rep 2018; 8:14214. [PMID: 30242166 PMCID: PMC6155035 DOI: 10.1038/s41598-018-32340-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2018] [Accepted: 07/20/2018] [Indexed: 12/14/2022] Open
Abstract
Tight control of gene expression is crucial for Mycobacterium tuberculosis to adapt to the changing environments encountered when infecting or exiting human cells. While three nucleoid associated proteins (NAPs) EspR, HupB and Lsr2 have been investigated, the role of a fourth, the mycobacterial integration host factor (mIHF), remains elusive. Here, we report a multidisciplinary functional analysis that exploits a conditional mIHF mutant. Gene silencing was bactericidal and resulted in elongated cells devoid of septa, with only one nucleoid. ChIP-sequencing identified 153 broad peaks distributed around the chromosome, which were often situated upstream of transcriptional start sites where EspR also bound. RNA-sequencing showed expression of 209 genes to be heavily affected upon mIHF depletion, including those for many tRNAs, DNA synthesis and virulence pathways. Consistent with NAP function, mIHF acts as a global regulator by directly and indirectly controlling genes required for pathogenesis and for housekeeping functions.
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40
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Chawla M, Mishra S, Anand K, Parikh P, Mehta M, Vij M, Verma T, Singh P, Jakkala K, Verma HN, AjitKumar P, Ganguli M, Narain Seshasayee AS, Singh A. Redox-dependent condensation of the mycobacterial nucleoid by WhiB4. Redox Biol 2018; 19:116-133. [PMID: 30149290 PMCID: PMC6111044 DOI: 10.1016/j.redox.2018.08.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 08/02/2018] [Accepted: 08/11/2018] [Indexed: 12/22/2022] Open
Abstract
Oxidative stress response in bacteria is mediated through coordination between the regulators of oxidant-remediation systems (e.g. OxyR, SoxR) and nucleoid condensation (e.g. Dps, Fis). However, these genetic factors are either absent or rendered non-functional in the human pathogen Mycobacterium tuberculosis (Mtb). Therefore, how Mtb organizes genome architecture and regulates gene expression to counterbalance oxidative imbalance is unknown. Here, we report that an intracellular redox-sensor, WhiB4, dynamically links genome condensation and oxidative stress response in Mtb. Disruption of WhiB4 affects the expression of genes involved in maintaining redox homeostasis, central metabolism, and respiration under oxidative stress. Notably, disulfide-linked oligomerization of WhiB4 in response to oxidative stress activates the protein’s ability to condense DNA. Further, overexpression of WhiB4 led to hypercondensation of nucleoids, redox imbalance and increased susceptibility to oxidative stress, whereas WhiB4 disruption reversed this effect. In accordance with the findings in vitro, ChIP-Seq data demonstrated non-specific binding of WhiB4 to GC-rich regions of the Mtb genome. Lastly, data indicate that WhiB4 deletion affected the expression of ~ 30% of genes preferentially bound by the protein, suggesting both direct and indirect effects on gene expression. We propose that WhiB4 structurally couples Mtb’s response to oxidative stress with genome organization and transcription. Genome condensation is involved in the management of oxidative stress in bacteria. A relation between the genome condensation and oxidative stress is unclear in Mtb. A redox sensor WhiB4 calibrates genome-condensation and antioxidants in Mtb. Over-expression of WhiB4 hyper-condensed genome and induced killing by oxidants. WhiB4 deficiency delayed genome condensation and promoted oxidative stress survival.
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Affiliation(s)
- Manbeena Chawla
- Department of Microbiology and Cell Biology, Centre for Infectious Disease Research, Indian Institute of Science, Bangalore 560012, India
| | - Saurabh Mishra
- Department of Microbiology and Cell Biology, Centre for Infectious Disease Research, Indian Institute of Science, Bangalore 560012, India
| | - Kushi Anand
- Department of Microbiology and Cell Biology, Centre for Infectious Disease Research, Indian Institute of Science, Bangalore 560012, India
| | - Pankti Parikh
- Department of Microbiology and Cell Biology, Centre for Infectious Disease Research, Indian Institute of Science, Bangalore 560012, India
| | - Mansi Mehta
- Department of Microbiology and Cell Biology, Centre for Infectious Disease Research, Indian Institute of Science, Bangalore 560012, India
| | - Manika Vij
- Department of Structural Biology, CSIR-Institute of Genomics and Integrative Biology, South Campus, Mathura Road, New Delhi 110020, India; Academy of Scientific and Innovative Research (AcSIR), Anusandhan Bhawan, 2 Rafi Marg, New Delhi 110001, India
| | - Taru Verma
- Department of Microbiology and Cell Biology, Centre for Infectious Disease Research, Indian Institute of Science, Bangalore 560012, India; Centre for BioSystems Science and Engineering (BSSE), Indian Institute of Science, Bangalore 560012, India
| | - Parul Singh
- National Centre for Biological Science, Bangalore 560065, India; SASTRA University, Thanjavur 613401, Tamil Nadu, India
| | - Kishor Jakkala
- Department of Microbiology and Cell Biology, Centre for Infectious Disease Research, Indian Institute of Science, Bangalore 560012, India
| | - H N Verma
- Jaipur National University, Jagatpura, Jaipur 302017, India
| | - Parthasarathi AjitKumar
- Department of Microbiology and Cell Biology, Centre for Infectious Disease Research, Indian Institute of Science, Bangalore 560012, India
| | - Munia Ganguli
- Department of Structural Biology, CSIR-Institute of Genomics and Integrative Biology, South Campus, Mathura Road, New Delhi 110020, India; Academy of Scientific and Innovative Research (AcSIR), Anusandhan Bhawan, 2 Rafi Marg, New Delhi 110001, India
| | | | - Amit Singh
- Department of Microbiology and Cell Biology, Centre for Infectious Disease Research, Indian Institute of Science, Bangalore 560012, India.
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41
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Ates LS, Dippenaar A, Sayes F, Pawlik A, Bouchier C, Ma L, Warren RM, Sougakoff W, Majlessi L, van Heijst JWJ, Brossier F, Brosch R. Unexpected Genomic and Phenotypic Diversity of Mycobacterium africanum Lineage 5 Affects Drug Resistance, Protein Secretion, and Immunogenicity. Genome Biol Evol 2018; 10:1858-1874. [PMID: 30010947 PMCID: PMC6071665 DOI: 10.1093/gbe/evy145] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/10/2018] [Indexed: 01/19/2023] Open
Abstract
Mycobacterium africanum consists of Lineages L5 and L6 of the Mycobacterium tuberculosis complex (MTBC) and causes human tuberculosis in specific regions of Western Africa, but is generally not transmitted in other parts of the world. Since M. africanum is evolutionarily closely placed between the globally dispersed Mycobacterium tuberculosis and animal-adapted MTBC-members, these lineages provide valuable insight into M. tuberculosis evolution. Here, we have collected 15 M. africanum L5 strains isolated in France over 4 decades. Illumina sequencing and phylogenomic analysis revealed a previously underappreciated diversity within L5, which consists of distinct sublineages. L5 strains caused relatively high levels of extrapulmonary tuberculosis and included multi- and extensively drug-resistant isolates, especially in the newly defined sublineage L5.2. The specific L5 sublineages also exhibit distinct phenotypic characteristics related to in vitro growth, protein secretion and in vivo immunogenicity. In particular, we identified a PE_PGRS and PPE-MPTR secretion defect specific for sublineage L5.2, which was independent of PPE38. Furthermore, L5 isolates were able to efficiently secrete and induce immune responses against ESX-1 substrates contrary to previous predictions. These phenotypes of Type VII protein secretion and immunogenicity provide valuable information to better link genome sequences to phenotypic traits and thereby understand the evolution of the MTBC.
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Affiliation(s)
- Louis S Ates
- Department of Genomes and Genetics, Institut Pasteur, Unit for Integrated Mycobacterial Pathogenomics, CNRS UMR3525, Paris, France
- Department of Experimental Immunology, Amsterdam UMC, University of Amsterdam, Amsterdam Infection & Immunity Institute, Amsterdam, The Netherlands
| | - Anzaan Dippenaar
- DST-NRF Centre of Excellence for Biomedical Tuberculosis Research; South African Medical Research Council Centre for Tuberculosis Research; Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Fadel Sayes
- Department of Genomes and Genetics, Institut Pasteur, Unit for Integrated Mycobacterial Pathogenomics, CNRS UMR3525, Paris, France
| | - Alexandre Pawlik
- Department of Genomes and Genetics, Institut Pasteur, Unit for Integrated Mycobacterial Pathogenomics, CNRS UMR3525, Paris, France
| | - Christiane Bouchier
- Department of Genomes and Genetics, Institut Pasteur, Genomics Platform, Paris, France
| | - Laurence Ma
- Department of Genomes and Genetics, Institut Pasteur, Genomics Platform, Paris, France
| | - Robin M Warren
- DST-NRF Centre of Excellence for Biomedical Tuberculosis Research; South African Medical Research Council Centre for Tuberculosis Research; Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Wladimir Sougakoff
- Sorbonne Universités, INSERM, Centre d'Immunologie et des Maladies Infectieuses, CIMI-Paris, Team 13 (Bacteriology), Paris, France
- Laboratoire de Bactériologie-Hygiène, Centre National de Référence des Mycobactéries (NRC MyRMA), Hôpitaux Universitaires Pitié-Salpêtrière – Charles Foix, Paris, France
| | - Laleh Majlessi
- Department of Genomes and Genetics, Institut Pasteur, Unit for Integrated Mycobacterial Pathogenomics, CNRS UMR3525, Paris, France
| | - Jeroen W J van Heijst
- Department of Experimental Immunology, Amsterdam UMC, University of Amsterdam, Amsterdam Infection & Immunity Institute, Amsterdam, The Netherlands
| | - Florence Brossier
- Department of Genomes and Genetics, Institut Pasteur, Unit for Integrated Mycobacterial Pathogenomics, CNRS UMR3525, Paris, France
- Sorbonne Universités, INSERM, Centre d'Immunologie et des Maladies Infectieuses, CIMI-Paris, Team 13 (Bacteriology), Paris, France
- Laboratoire de Bactériologie-Hygiène, Centre National de Référence des Mycobactéries (NRC MyRMA), Hôpitaux Universitaires Pitié-Salpêtrière – Charles Foix, Paris, France
| | - Roland Brosch
- Department of Genomes and Genetics, Institut Pasteur, Unit for Integrated Mycobacterial Pathogenomics, CNRS UMR3525, Paris, France
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42
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RpoN-Dependent Direct Regulation of Quorum Sensing and the Type VI Secretion System in Pseudomonas aeruginosa PAO1. J Bacteriol 2018; 200:JB.00205-18. [PMID: 29760208 DOI: 10.1128/jb.00205-18] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Accepted: 05/09/2018] [Indexed: 12/23/2022] Open
Abstract
Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen of humans, particularly those with cystic fibrosis. As a global regulator, RpoN controls a group of virulence-related factors and quorum-sensing (QS) genes in P. aeruginosa To gain further insights into the direct targets of RpoN in vivo, the present study focused on identifying the direct targets of RpoN regulation in QS and the type VI secretion system (T6SS). We performed chromatin immunoprecipitation coupled with high-throughput sequencing (ChIP-seq) that identified 1,068 binding sites of RpoN, mostly including metabolic genes, a group of genes in QS (lasI, rhlI, and pqsR) and the T6SS (hcpA and hcpB). The direct targets of RpoN have been verified by electrophoretic mobility shifts assays (EMSA), lux reporter assay, reverse transcription-quantitative PCR, and phenotypic detection. The ΔrpoN::Tc mutant resulted in the reduced production of pyocyanin, motility, and proteolytic activity. However, the production of rhamnolipids and biofilm formation were higher in the ΔrpoN::Tc mutant than in the wild type. In summary, the results indicated that RpoN had direct and profound effects on QS and the T6SS.IMPORTANCE As a global regulator, RpoN controls a wide range of biological pathways, including virulence in P. aeruginosa PAO1. This work shows that RpoN plays critical and global roles in the regulation of bacterial pathogenicity and fitness. ChIP-seq provided a useful database to characterize additional functions and targets of RpoN in the future. The functional characterization of RpoN-mediated regulation will improve the current understanding of the regulatory network of quorum sensing and virulence in P. aeruginosa and other bacteria.
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43
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Evolution of virulence in the Mycobacterium tuberculosis complex. Curr Opin Microbiol 2018; 41:68-75. [DOI: 10.1016/j.mib.2017.11.021] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 10/27/2017] [Accepted: 11/04/2017] [Indexed: 01/16/2023]
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44
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Gago G, Diacovich L, Gramajo H. Lipid metabolism and its implication in mycobacteria-host interaction. Curr Opin Microbiol 2018; 41:36-42. [PMID: 29190491 PMCID: PMC5862736 DOI: 10.1016/j.mib.2017.11.020] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2017] [Revised: 11/06/2017] [Accepted: 11/07/2017] [Indexed: 12/16/2022]
Abstract
The complex lipids present in the cell wall of Mycobacterium tuberculosis (Mtb) act as major effector molecules that actively interact with the host, modulating its metabolism and stimulating the immune response, which in turn affects the physiology of both, the host cell and the bacilli. Lipids from the host are also nutrient sources for the pathogen and define the fate of the infection by modulating lipid homeostasis. Although new technologies and experimental models of infection have greatly helped understanding the different aspects of the host-pathogen interactions at the lipid level, the impact of this interaction in the Mtb lipid regulation is still incipient, mainly because of the low background knowledge in this area of research.
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Affiliation(s)
- Gabriela Gago
- Laboratory of Physiology and Genetics of Actinomycetes, Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Lautaro Diacovich
- Laboratory of Physiology and Genetics of Actinomycetes, Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Hugo Gramajo
- Laboratory of Physiology and Genetics of Actinomycetes, Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina.
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45
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Zondervan NA, van Dam JCJ, Schaap PJ, Martins Dos Santos VAP, Suarez-Diez M. Regulation of Three Virulence Strategies of Mycobacterium tuberculosis: A Success Story. Int J Mol Sci 2018; 19:E347. [PMID: 29364195 PMCID: PMC5855569 DOI: 10.3390/ijms19020347] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Revised: 01/19/2018] [Accepted: 01/21/2018] [Indexed: 12/28/2022] Open
Abstract
Tuberculosis remains one of the deadliest diseases. Emergence of drug-resistant and multidrug-resistant M. tuberculosis strains makes treating tuberculosis increasingly challenging. In order to develop novel intervention strategies, detailed understanding of the molecular mechanisms behind the success of this pathogen is required. Here, we review recent literature to provide a systems level overview of the molecular and cellular components involved in divalent metal homeostasis and their role in regulating the three main virulence strategies of M. tuberculosis: immune modulation, dormancy and phagosomal rupture. We provide a visual and modular overview of these components and their regulation. Our analysis identified a single regulatory cascade for these three virulence strategies that respond to limited availability of divalent metals in the phagosome.
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Affiliation(s)
- Niels A Zondervan
- Laboratory of Systems and Synthetic Biology, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands.
| | - Jesse C J van Dam
- Laboratory of Systems and Synthetic Biology, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands.
| | - Peter J Schaap
- Laboratory of Systems and Synthetic Biology, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands.
| | - Vitor A P Martins Dos Santos
- Laboratory of Systems and Synthetic Biology, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands.
- LifeGlimmer GmbH, Markelstrasse 38, 12163 Berlin, Germany.
| | - Maria Suarez-Diez
- Laboratory of Systems and Synthetic Biology, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands.
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46
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Kriel NL, Gallant J, van Wyk N, van Helden P, Sampson SL, Warren RM, Williams MJ. Mycobacterial nucleoid associated proteins: An added dimension in gene regulation. Tuberculosis (Edinb) 2018. [DOI: 10.1016/j.tube.2017.12.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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47
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Anand C, Garg R, Ghosh S, Nagaraja V. A Sir2 family protein Rv1151c deacetylates HU to alter its DNA binding mode in Mycobacterium tuberculosis. Biochem Biophys Res Commun 2017; 493:1204-1209. [PMID: 28935371 DOI: 10.1016/j.bbrc.2017.09.087] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 09/15/2017] [Indexed: 11/29/2022]
Abstract
Till recently, knowledge about epigenetic regulation in bacterial world confined largely to DNA methylation. Lysine acetylation/deacetylation of histones is a major contributor for chromatin dynamics in eukaryotes. However, little is known about such epigenetic changes brought about by post-translational modifications in bacteria. Here, we describe an example of such mechanism occurring in a histone like protein, HU from Mycobacterium tuberculosis (Mtb). Previously, we demonstrated the interaction and acetylation of Mtb HU (MtHU) by one of the acetyl transferases, Eis. In this work, we demonstrate the deacetylation of acetylated HU (MtHUAc) by Rv1151c, the only Sir2 like protein discovered in Mtb. The DNA binding properties of MtHU are significantly altered upon acetylation but reversed consequent to deacetylation by the deacetylase. Deacetylated HU (MtHUdAc) bound to relaxed DNA leading to the formation of looped and dense molecules as compared to open structures formed by its acetylated form. Interaction of MtHUdAc with linear DNA modifies its organization leading to formation of highly bridged compact structures while binding of MtHUAc leads to the formation of stiff and straight rods. That a nucleoid associated protein can undergo acetylation/deacetylation to alter its DNA binding and architectural role opens up a new dimension of investigation of epigenetic regulation in mycobacteria.
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Affiliation(s)
- Chinmay Anand
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, Karnataka, 560012, India
| | - Rajni Garg
- Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, Karnataka, 560064, India
| | - Soumitra Ghosh
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, Karnataka, 560012, India
| | - Valakunja Nagaraja
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, Karnataka, 560012, India; Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, Karnataka, 560064, India.
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Abstract
Mycobacterial 6-kDa early secreted antigenic target (ESAT-6) system (ESX) exporters transport proteins across the cytoplasmic membrane. Many proteins transported by ESX systems are then translocated across the mycobacterial cell envelope and secreted from the cell. Although the mechanism underlying protein transport across the mycolate outer membrane remains elusive, the ESX systems are closely connected with and localize to the cell envelope. Links between ESX-associated proteins, cell wall synthesis, and the maintenance of cell envelope integrity have been reported. Genes encoding the ESX systems and those required for biosynthesis of the mycobacterial envelope are coregulated. Here, we review the interplay between ESX systems and the mycobacterial cell envelope.
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Rv3852 (H-NS) of Mycobacterium tuberculosis Is Not Involved in Nucleoid Compaction and Virulence Regulation. J Bacteriol 2017; 199:JB.00129-17. [PMID: 28559300 DOI: 10.1128/jb.00129-17] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 05/25/2017] [Indexed: 02/05/2023] Open
Abstract
A handful of nucleoid-associated proteins (NAPs) regulate the vast majority of genes in a bacterial cell. H-NS, the histone-like nucleoid-structuring protein, is one of these NAPs and protects Escherichia coli from foreign gene expression. Though lacking any sequence similarity with E. coli H-NS, Rv3852 was annotated as the H-NS ortholog in Mycobacterium tuberculosis, as it resembles human histone H1. The role of Rv3852 was thoroughly investigated by immunoblotting, subcellular localization, construction of an unmarked rv3852 deletion in the M. tuberculosis genome, and subsequent analysis of the resulting Δrv3852 strain. We found that Rv3852 was predominantly present in the logarithmic growth phase with a decrease in protein abundance in stationary phase. Furthermore, it was strongly associated with the cell membrane and not detected in the cytosolic fraction, nor was it secreted. The Δrv3852 strain displayed no growth defect or morphological abnormalities. Quantitative measurement of nucleoid localization in the Δrv3852 mutant strain compared to that in the parental H37Rv strain showed no difference in nucleoid position or spread. Infection of macrophages as well as severe combined immunodeficient (SCID) mice demonstrated that loss of Rv3852 had no detected influence on the virulence of M. tuberculosis We thus conclude that M. tuberculosis Rv3852 is not involved in pathogenesis and is not a typical NAP. The existence of an as yet undiscovered Rv3852 ortholog cannot be excluded, although this role is likely played by the well-characterized Lsr2 protein.IMPORTANCEMycobacterium tuberculosis is the causative agent of the lung infection tuberculosis, claiming more than 1.5 million lives each year. To understand the mechanisms of latent infection, where M. tuberculosis can stay dormant inside the human host, we require deeper knowledge of the basic biology and of the regulatory networks. In our work, we show that Rv3852, previously annotated as H-NS, is not a typical nucleoid-associated protein (NAP) as expected from its initial annotation. Rv3852 from M. tuberculosis has neither influence on nucleoid shape or compaction nor a role in virulence. Our findings reduce the repertoire of identified nucleoid-associated proteins in M. tuberculosis to four transcription regulators and underline the importance of genetic studies to assign a function to bacterial genes.
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50
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The Cell Wall Lipid PDIM Contributes to Phagosomal Escape and Host Cell Exit of Mycobacterium tuberculosis. mBio 2017; 8:mBio.00148-17. [PMID: 28270579 PMCID: PMC5340868 DOI: 10.1128/mbio.00148-17] [Citation(s) in RCA: 135] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The cell wall of Mycobacterium tuberculosis is composed of unique lipids that are important for pathogenesis. Indeed, the first-ever genetic screen in M. tuberculosis identified genes involved in the biosynthesis and transport of the cell wall lipid PDIM (phthiocerol dimycocerosates) as crucial for the survival of M. tuberculosis in mice. Here we show evidence for a novel molecular mechanism of the PDIM-mediated virulence in M. tuberculosis We characterized the DNA interaction and the regulon of Rv3167c, a transcriptional repressor that is involved in virulence regulation of M. tuberculosis, and discovered that it controls the PDIM operon. A loss-of-function genetic approach showed that PDIM levels directly correlate with the capacity of M. tuberculosis to escape the phagosome and induce host cell necrosis and macroautophagy. In conclusion, our study attributes a novel role of the cell wall lipid PDIM in intracellular host cell modulation, which is important for host cell exit and dissemination of M. tuberculosisIMPORTANCEMycobacterium tuberculosis is a major human pathogen that has coevolved with its host for thousands of years. The complex and unique cell wall of M. tuberculosis contains the lipid PDIM (phthiocerol dimycocerosates), which is crucial for virulence of the bacterium, but its function is not well understood. Here we show that PDIM expression by M. tuberculosis is negatively regulated by a novel transcriptional repressor, Rv3167c. In addition, we discovered that the escape of M. tuberculosis from its intracellular vacuole was greatly augmented by the presence of PDIM. The increased release of M. tuberculosis into the cytosol led to increased host cell necrosis. The discovery of a link between the cell wall lipid PDIM and a major pathogenesis pathway of M. tuberculosis provides important insights into the molecular mechanisms of host cell manipulation by M. tuberculosis.
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