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Cioetto-Mazzabò L, Sorze D, Babic F, Boldrin F, Segafreddo G, Provvedi R, Manganelli R. Structure of the SigE regulatory network in Mycobacterium tuberculosis. Front Microbiol 2024; 15:1407500. [PMID: 38873166 PMCID: PMC11173970 DOI: 10.3389/fmicb.2024.1407500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Accepted: 05/15/2024] [Indexed: 06/15/2024] Open
Abstract
SigE is one of the main regulators of mycobacterial stress response and is characterized by a complex regulatory network based on two pathways, which have been partially characterized in conditions of surface stress. The first pathway is based on the induction of sigE transcription by the two-component system MprAB, while the second is based on the degradation of SigE anti-sigma factor RseA by ClpC1P2, a protease whose structural genes are induced by ClgR. We characterized the dynamics of the SigE network activation in conditions of surface stress and low pH in Mycobacterium tuberculosis. Using a series of mutants in which the main regulatory nodes of the network have been inactivated, we could explore their hierarchy, and we determined that MprAB had a key role in the network activation in both stress conditions through the induction of sigE. However, while in conditions of surface stress the absence of MprAB totally abrogated sigE induction, under low pH conditions it only resulted in a small delay of the induction of sigE. In this case, sigE induction was due to SigH, which acted as a MprAB backup system. The ClgR pathway, leading to the degradation of the SigE anti-sigma factor RseA, was shown to be essential for the activation of the SigE network only following surface stress, where it showed an equal hierarchy with the MprAB pathway.
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Affiliation(s)
| | - Davide Sorze
- Department of Molecular Medicine, University of Padova, Padova, Italy
| | - Fedora Babic
- Department of Molecular Medicine, University of Padova, Padova, Italy
| | - Francesca Boldrin
- Department of Molecular Medicine, University of Padova, Padova, Italy
| | - Greta Segafreddo
- Department of Molecular Medicine, University of Padova, Padova, Italy
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Nelson SJ, Williams JT, Buglino JA, Nambi S, Lojek LJ, Glickman MS, Ioerger TR, Sassetti CM. The Rip1 intramembrane protease contributes to iron and zinc homeostasis in Mycobacterium tuberculosis. mSphere 2023; 8:e0038922. [PMID: 37318217 PMCID: PMC10449499 DOI: 10.1128/msphere.00389-22] [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: 08/11/2022] [Accepted: 04/28/2023] [Indexed: 06/16/2023] Open
Abstract
Mycobacterium tuberculosis is exposed to a variety of stresses during a chronic infection, as the immune system simultaneously produces bactericidal compounds and starves the pathogen of essential nutrients. The intramembrane protease, Rip1, plays an important role in the adaptation to these stresses, at least partially by the cleavage of membrane-bound transcriptional regulators. Although Rip1 is known to be critical for surviving copper intoxication and nitric oxide exposure, these stresses do not fully account for the regulatory protein's essentiality during infection. In this work, we demonstrate that Rip1 is also necessary for growth in low-iron and low-zinc conditions, similar to those imposed by the immune system. Using a newly generated library of sigma factor mutants, we show that the known regulatory target of Rip1, SigL, shares this defect. Transcriptional profiling under iron-limiting conditions supported the coordinated activity of Rip1 and SigL and demonstrated that the loss of these proteins produces an exaggerated iron starvation response. These observations demonstrate that Rip1 coordinates several aspects of metal homeostasis and suggest that a Rip1- and SigL-dependent pathway is necessary to thrive in the iron-deficient environments encountered during infection. IMPORTANCE Metal homeostasis represents a critical point of interaction between the mammalian immune system and potential pathogens. While the host attempts to intoxicate microbes with high concentrations of copper or starve the invader of iron and zinc, successful pathogens have acquired mechanisms to overcome these defenses. Our work identifies a regulatory pathway consisting of the Rip1 intramembrane protease and the sigma factor, SigL, that is essential for the important human pathogen, Mycobacterium tuberculosis, to grow in low-iron or low-zinc conditions such as those encountered during infection. In conjunction with Rip1's known role in resisting copper toxicity, our work implicates this protein as a critical integration point that coordinates the multiple metal homeostatic systems required for this pathogen to survive in host tissue.
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Affiliation(s)
- Samantha J. Nelson
- Department of Microbiology and Physiological Systems, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA
| | - John T. Williams
- Department of Microbiology and Physiological Systems, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA
| | - John A. Buglino
- Immunology Program, Sloan Kettering Institute, New York City, New York, USA
| | - Subhalaxmi Nambi
- Department of Microbiology and Physiological Systems, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA
| | - Lisa J. Lojek
- Department of Microbiology and Physiological Systems, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA
| | | | - Thomas R. Ioerger
- Department of Computer Science and Engineering, Texas A&M University, College Station, Texas, USA
| | - Christopher M. Sassetti
- Department of Microbiology and Physiological Systems, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA
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3
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Manganelli R, Cioetto-Mazzabò L, Segafreddo G, Boldrin F, Sorze D, Conflitti M, Serafini A, Provvedi R. SigE: A master regulator of Mycobacterium tuberculosis. Front Microbiol 2023; 14:1075143. [PMID: 36960291 PMCID: PMC10027907 DOI: 10.3389/fmicb.2023.1075143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 02/16/2023] [Indexed: 03/09/2023] Open
Abstract
The Extracellular function (ECF) sigma factor SigE is one of the best characterized out of the 13 sigma factors encoded in the Mycobacterium tuberculosis chromosome. SigE is required for blocking phagosome maturation and full virulence in both mice and guinea pigs. Moreover, it is involved in the response to several environmental stresses as surface stress, oxidative stress, acidic pH, and phosphate starvation. Underscoring its importance in M. tuberculosis physiology, SigE is subjected to a very complex regulatory system: depending on the environmental conditions, its expression is regulated by three different sigma factors (SigA, SigE, and SigH) and a two-component system (MprAB). SigE is also regulated at the post-translational level by an anti-sigma factor (RseA) which is regulated by the intracellular redox potential and by proteolysis following phosphorylation from PknB upon surface stress. The set of genes under its direct control includes other regulators, as SigB, ClgR, and MprAB, and genes involved in surface remodeling and stabilization. Recently SigE has been shown to interact with PhoP to activate a subset of genes in conditions of acidic pH. The complex structure of its regulatory network has been suggested to result in a bistable switch leading to the development of heterogeneous bacterial populations. This hypothesis has been recently reinforced by the finding of its involvement in the development of persister cells able to survive to the killing activity of several drugs.
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Affiliation(s)
| | | | - Greta Segafreddo
- Department of Molecular Medicine, University of Padova, Padova, Italy
| | - Francesca Boldrin
- Department of Molecular Medicine, University of Padova, Padova, Italy
| | - Davide Sorze
- Department of Molecular Medicine, University of Padova, Padova, Italy
| | - Marta Conflitti
- Department of Molecular Medicine, University of Padova, Padova, Italy
| | - Agnese Serafini
- Department of Molecular Medicine, University of Padova, Padova, Italy
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Xu X, Zhang L, Yang T, Qiu Z, Bai L, Luo Y. Targeting caseinolytic protease P and its AAA1 chaperone for tuberculosis treatment. Drug Discov Today 2023; 28:103508. [PMID: 36706830 DOI: 10.1016/j.drudis.2023.103508] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 01/11/2023] [Accepted: 01/19/2023] [Indexed: 01/26/2023]
Abstract
Caseinolytic protease P with its AAA1 chaperone, known as Mycobacterium tuberculosis (Mtb)ClpP1P2 proteolytic machinery, maintains protein homeostasis in Mtb cells and is essential for bacterial survival. It is regarded as an important biological target with the potential to address the increasingly serious issue of multidrug-resistant (MDR) TB. Over the past 10 years, many MtbClpP1P2-targeted modulators have been identified and characterized, some of which have shown potent anti-TB activity. In this review, we describe current understanding of the substrates, structure and function of MtbClpP1P2, classify the modulators of this important protein machine into several categories based on their binding subunits or pockets, and discuss their binding details; Such information provides insights for use in candidate drug research and development of TB treatments by targeting MtbClpP1P2 proteolytic machinery.
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Affiliation(s)
- Xin Xu
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China
| | - Laiying Zhang
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China
| | - Tao Yang
- Laboratory of Human Diseases and Immunotherapy, West China Hospital, Sichuan University, Chengdu 610041, China; Institute of Immunology and Inflammation, Frontiers Science Center for Disease-related Molecular Network, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Zhiqiang Qiu
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China
| | - Lang Bai
- Center of Infectious Diseases and State Key Laboratory of Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China.
| | - Youfu Luo
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China.
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5
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Oh Y, Lee HN, Ko EM, Jeong JA, Park SW, Oh JI. Mycobacterial Regulatory Systems Involved in the Regulation of Gene Expression Under Respiration-Inhibitory Conditions. J Microbiol 2023; 61:297-315. [PMID: 36847970 DOI: 10.1007/s12275-023-00026-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 01/31/2023] [Accepted: 02/01/2023] [Indexed: 03/01/2023]
Abstract
Mycobacterium tuberculosis is the causative agent of tuberculosis. M. tuberculosis can survive in a dormant state within the granuloma, avoiding the host-mounting immune attack. M. tuberculosis bacilli in this state show increased tolerance to antibiotics and stress conditions, and thus the transition of M. tuberculosis to the nonreplicating dormant state acts as an obstacle to tuberculosis treatment. M. tuberculosis in the granuloma encounters hostile environments such as hypoxia, nitric oxide, reactive oxygen species, low pH, and nutrient deprivation, etc., which are expected to inhibit respiration of M. tuberculosis. To adapt to and survive in respiration-inhibitory conditions, it is required for M. tuberculosis to reprogram its metabolism and physiology. In order to get clues to the mechanism underlying the entry of M. tuberculosis to the dormant state, it is important to understand the mycobacterial regulatory systems that are involved in the regulation of gene expression in response to respiration inhibition. In this review, we briefly summarize the information regarding the regulatory systems implicated in upregulation of gene expression in mycobacteria exposed to respiration-inhibitory conditions. The regulatory systems covered in this review encompass the DosSR (DevSR) two-component system, SigF partner switching system, MprBA-SigE-SigB signaling pathway, cAMP receptor protein, and stringent response.
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Affiliation(s)
- Yuna Oh
- Department of Integrated Biological Science, Pusan National University, Busan, 46241, Republic of Korea
| | - Ha-Na Lee
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, NY, 10065, USA
| | - Eon-Min Ko
- Division of Bacterial Disease Research, Center for Infectious Disease Research, Korea Disease Control and Prevention Agency, National Institute of Infectious Diseases, National Institute of Health, Osong, 28159, Republic of Korea
| | - Ji-A Jeong
- Division of Bacterial Disease Research, Center for Infectious Disease Research, Korea Disease Control and Prevention Agency, National Institute of Infectious Diseases, National Institute of Health, Osong, 28159, Republic of Korea
| | - Sae Woong Park
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, NY, 10065, USA
| | - Jeong-Il Oh
- Department of Integrated Biological Science, Pusan National University, Busan, 46241, Republic of Korea. .,Microbiological Resource Research Institute, Pusan National University, Busan, 46241, Republic of Korea.
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Miotto P, Sorrentino R, De Giorgi S, Provvedi R, Cirillo DM, Manganelli R. Transcriptional regulation and drug resistance in Mycobacterium tuberculosis. Front Cell Infect Microbiol 2022; 12:990312. [PMID: 36118045 PMCID: PMC9480834 DOI: 10.3389/fcimb.2022.990312] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2022] [Accepted: 08/11/2022] [Indexed: 11/13/2022] Open
Abstract
Bacterial drug resistance is one of the major challenges to present and future human health, as the continuous selection of multidrug resistant bacteria poses at serious risk the possibility to treat infectious diseases in the near future. One of the infection at higher risk to become incurable is tuberculosis, due to the few drugs available in the market against Mycobacterium tuberculosis. Drug resistance in this species is usually due to point mutations in the drug target or in proteins required to activate prodrugs. However, another interesting and underexplored aspect of bacterial physiology with important impact on drug susceptibility is represented by the changes in transcriptional regulation following drug exposure. The main regulators involved in this phenomenon in M. tuberculosis are the sigma factors, and regulators belonging to the WhiB, GntR, XRE, Mar and TetR families. Better understanding the impact of these regulators in survival to drug treatment might contribute to identify new drug targets and/or to design new strategies of intervention.
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Affiliation(s)
- Paolo Miotto
- Emerging Bacterial Pathogens Unit, Div. of Immunology, Transplantation and Infectious Diseases IRCCS San Raffaele Scientific Institute, Milano, Italy
| | - Rita Sorrentino
- Emerging Bacterial Pathogens Unit, Div. of Immunology, Transplantation and Infectious Diseases IRCCS San Raffaele Scientific Institute, Milano, Italy
| | - Stefano De Giorgi
- Department of Molecular Medicine, University of Padova, Padova, Italy
| | | | - Daniela Maria Cirillo
- Emerging Bacterial Pathogens Unit, Div. of Immunology, Transplantation and Infectious Diseases IRCCS San Raffaele Scientific Institute, Milano, Italy
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Activation of the SigE-SigB signaling pathway by inhibition of the respiratory electron transport chain and its effect on rifampicin resistance in Mycobacterium smegmatis. J Microbiol 2022; 60:935-947. [DOI: 10.1007/s12275-022-2202-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 07/01/2022] [Accepted: 07/05/2022] [Indexed: 10/16/2022]
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Marcos-Torres FJ, Moraleda-Muñoz A, Contreras-Moreno FJ, Muñoz-Dorado J, Pérez J. Mechanisms of Action of Non-Canonical ECF Sigma Factors. Int J Mol Sci 2022; 23:ijms23073601. [PMID: 35408957 PMCID: PMC8999054 DOI: 10.3390/ijms23073601] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 03/23/2022] [Accepted: 03/24/2022] [Indexed: 02/04/2023] Open
Abstract
Extracytoplasmic function (ECF) sigma factors are subunits of the RNA polymerase specialized in activating the transcription of a subset of genes responding to a specific environmental condition. The signal-transduction pathways where they participate can be activated by diverse mechanisms. The most common mechanism involves the action of a membrane-bound anti-sigma factor, which sequesters the ECF sigma factor, and releases it after the stimulus is sensed. However, despite most of these systems following this canonical regulation, there are many ECF sigma factors exhibiting a non-canonical regulatory mechanism. In this review, we aim to provide an updated and comprehensive view of the different activation mechanisms known for non-canonical ECF sigma factors, detailing their inclusion to the different phylogenetic groups and describing the mechanisms of regulation of some of their representative members such as EcfG from Rhodobacter sphaeroides, showing a partner-switch mechanism; EcfP from Vibrio parahaemolyticus, with a phosphorylation-dependent mechanism; or CorE from Myxococcus xanthus, regulated by a metal-sensing C-terminal extension.
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Affiliation(s)
| | - Aurelio Moraleda-Muñoz
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Granada, Avda, Fuentenueva s/n, 18071 Granada, Spain; (F.J.C.-M.); (J.M.-D.)
- Correspondence: (A.M.-M.); (J.P.); Tel.: +34-95-824-2858 (A.M.-M.); +34-95-824-9830 (J.P.)
| | - Francisco Javier Contreras-Moreno
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Granada, Avda, Fuentenueva s/n, 18071 Granada, Spain; (F.J.C.-M.); (J.M.-D.)
| | - José Muñoz-Dorado
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Granada, Avda, Fuentenueva s/n, 18071 Granada, Spain; (F.J.C.-M.); (J.M.-D.)
| | - Juana Pérez
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Granada, Avda, Fuentenueva s/n, 18071 Granada, Spain; (F.J.C.-M.); (J.M.-D.)
- Correspondence: (A.M.-M.); (J.P.); Tel.: +34-95-824-2858 (A.M.-M.); +34-95-824-9830 (J.P.)
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9
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Zorzan I, Del Favero S, Giaretta A, Manganelli R, Di Camillo B, Schenato L. Mathematical modelling of SigE regulatory network reveals new insights into bistability of mycobacterial stress response. BMC Bioinformatics 2021; 22:558. [PMID: 34798803 PMCID: PMC8605609 DOI: 10.1186/s12859-021-04372-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 09/11/2021] [Indexed: 12/19/2022] Open
Abstract
Background The ability to rapidly adapt to adverse environmental conditions represents the key of success of many pathogens and, in particular, of Mycobacterium tuberculosis. Upon exposition to heat shock, antibiotics or other sources of stress, appropriate responses in terms of genes transcription and proteins activity are activated leading part of a genetically identical bacterial population to express a different phenotype, namely to develop persistence. When the stress response network is mathematically described by an ordinary differential equations model, development of persistence in the bacterial population is associated with bistability of the model, since different emerging phenotypes are represented by different stable steady states. Results In this work, we develop a mathematical model of SigE stress response network that incorporates interactions not considered in mathematical models currently available in the literature. We provide, through involved analytical computations, accurate approximations of the system’s nullclines, and exploit the obtained expressions to determine, in a reliable though computationally efficient way, the number of equilibrium points of the system. Conclusions Theoretical analysis and perturbation experiments point out the crucial role played by the degradation pathway involving RseA, the anti-sigma factor of SigE, for coexistence of two stable equilibria and the emergence of bistability. Our results also indicate that a fine control on RseA concentration is a necessary requirement in order for the system to exhibit bistability. Supplementary Information The online version contains supplementary material available at 10.1186/s12859-021-04372-5.
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Affiliation(s)
- Irene Zorzan
- Department of Information Engineering, University of Padova, 35131, Padova, Italy.
| | - Simone Del Favero
- Department of Information Engineering, University of Padova, 35131, Padova, Italy
| | - Alberto Giaretta
- Department of Information Engineering, University of Padova, 35131, Padova, Italy
| | - Riccardo Manganelli
- Department of Molecular Medicine, University of Padova, 35121, Padova, Italy
| | - Barbara Di Camillo
- Department of Information Engineering, University of Padova, 35131, Padova, Italy.,Department of Comparative Biomedicine and Food Science, University of Padova, 35020, Legnaro (Padova), Italy
| | - Luca Schenato
- Department of Information Engineering, University of Padova, 35131, Padova, Italy
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Thiede JM, Dillon NA, Howe MD, Aflakpui R, Modlin SJ, Hoffner SE, Valafar F, Minato Y, Baughn AD. Pyrazinamide Susceptibility Is Driven by Activation of the SigE-Dependent Cell Envelope Stress Response in Mycobacterium tuberculosis. mBio 2021; 13:e0043921. [PMID: 35100871 PMCID: PMC8805019 DOI: 10.1128/mbio.00439-21] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 01/06/2022] [Indexed: 01/09/2023] Open
Abstract
Pyrazinamide (PZA) plays a crucial role in first-line tuberculosis drug therapy. Unlike other antimicrobial agents, PZA is active against Mycobacterium tuberculosis only at low pH. The basis for this conditional drug susceptibility remains undefined. In this study, we utilized a genome-wide approach to interrogate potentiation of PZA action. We found that mutations in numerous genes involved in central metabolism as well as cell envelope maintenance and stress response are associated with PZA resistance. Further, we demonstrate that constitutive activation of the cell envelope stress response can drive PZA susceptibility independent of environmental pH. Consequently, exposure to peptidoglycan synthesis inhibitors, such as beta-lactams and d-cycloserine, potentiate PZA action through triggering this response. These findings illuminate a regulatory mechanism for conditional PZA susceptibility and reveal new avenues for enhancing potency of this important drug through targeting activation of the cell envelope stress response. IMPORTANCE For decades, pyrazinamide has served as a cornerstone of tuberculosis therapy. Unlike any other antitubercular drug, pyrazinamide requires an acidic environment to exert its action. Despite its importance, the driver of this conditional susceptibility has remained unknown. In this study, a genome-wide approach revealed that pyrazinamide action is governed by the cell envelope stress response. This observation was validated by orthologous approaches that demonstrate that a central player of this response, SigE, is both necessary and sufficient for potentiation of pyrazinamide action. Moreover, constitutive activation of this response through deletion of the anti-sigma factor gene rseA or exposure of bacilli to drugs that target the cell wall was found to potently drive pyrazinamide susceptibility independent of environmental pH. These findings force a paradigm shift in our understanding of pyrazinamide action and open new avenues for improving diagnostic and therapeutic tools for tuberculosis.
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Affiliation(s)
- Joshua M. Thiede
- Department of Microbiology and Immunology, University of Minnesota Medical School, Minneapolis, Minnesota, USA
| | - Nicholas A. Dillon
- Department of Microbiology and Immunology, University of Minnesota Medical School, Minneapolis, Minnesota, USA
| | - Michael D. Howe
- Department of Microbiology and Immunology, University of Minnesota Medical School, Minneapolis, Minnesota, USA
| | - Ranee Aflakpui
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
| | - Samuel J. Modlin
- Laboratory for Pathogenesis of Clinical Drug Resistance and Persistence, Biomedical Informatics Research Center, Division of Epidemiology, School of Public Health, San Diego State University, San Diego, California, USA
| | - Sven E. Hoffner
- Laboratory for Pathogenesis of Clinical Drug Resistance and Persistence, Biomedical Informatics Research Center, Division of Epidemiology, School of Public Health, San Diego State University, San Diego, California, USA
- Department of Global Public Health, Karolinska Institute, Stockholm, Sweden
| | - Faramarz Valafar
- Laboratory for Pathogenesis of Clinical Drug Resistance and Persistence, Biomedical Informatics Research Center, Division of Epidemiology, School of Public Health, San Diego State University, San Diego, California, USA
| | - Yusuke Minato
- Department of Microbiology and Immunology, University of Minnesota Medical School, Minneapolis, Minnesota, USA
- Department of Microbiology, Fujita Health University School of Medicine, Toyoake, Japan
| | - Anthony D. Baughn
- Department of Microbiology and Immunology, University of Minnesota Medical School, Minneapolis, Minnesota, USA
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11
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Tamizi AA, Abu-Bakar N, Samsuddin AF, Rozano L, Ahmad-Redzuan R, Abdul-Murad AM. Characterisation and Mutagenesis Study of An Alternative Sigma Factor Gene ( hrpL) from Erwinia mallotivora Reveal Its Central Role in Papaya Dieback Disease. BIOLOGY 2020; 9:biology9100323. [PMID: 33023069 PMCID: PMC7600996 DOI: 10.3390/biology9100323] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 09/21/2020] [Accepted: 09/22/2020] [Indexed: 11/26/2022]
Abstract
Simple Summary Erwinia mallotivora is the causal agent of papaya dieback disease in Malaysia, and its pathogenicity is less appreciated, especially from the molecular perspective. Our previous investigations proved that the hrpL/rpoE gene was one of the significant differentially expressed genes (DEGs) during early infection of E. mallotivora in papaya, suggesting this particular gene is important for infection. In this study, an in-depth analysis was performed using bioinformatics software on hrpL from E. mallotivora (EmhrpL) and its encoded protein (EmHrpL) obtaining crucial information including the conserved function and sequence motif, protein structural similarity with related homologs, and the possibility of being inhibited by a cognate inhibitor. Moreover, knockout (insertional mutational on DNA sequence) of the hrpL gene had caused mutant E. mallotivora (ΔEmhrpL) to be avirulent in four-month-old papaya plants. Here, the conclusion was that EmHrpL is indeed a necessary factor in E. mallotivora pathogenicity, and the findings on the potential inhibitor of this protein are useful for future studies to formulate a papaya dieback disease management programme. Abstract The alternative sigma (σ) factor E, RpoE or HrpL, has been reported to be involved in stress- and pathogenicity-related transcription initiation in Escherichia coli and many other Gram-negative bacteria, including Erwinia spp. and Pseudomonas spp. A previous study identified the hrpL/rpoE transcript as one of the significant differentially expressed genes (DEGs) during early E. mallotivora infection in papaya and those data serve as the basis of the current project. Here, the full coding DNA sequence (CDS) of hrpL from E. mallotivora (EmhrpL) was determined to be 549 bp long, and it encoded a 21.3 kDa HrpL protein that possessed two highly conserved sigma-70 (σ70) motifs—σR2 and σR4. Nucleotide sequence alignment revealed the hrpL from E. mallotivora shared high sequence similarity to rpoE/hrpL from E. tracheiphila (83%), E. pyrifoliae (81%), and E. tasmaniensis (80%). Phylogenetics analysis indicated hrpL from E. mallotivora to be monophyletic with rpoEs/hrpLs from Pantoea vagans, E. herbicola, and E. tracheiphila. Structural analysis postulated that the E. mallotivora’s alternative σ factor was non-transmembranic and was an extracytoplasmic function (ECF) protein—characteristics shared by other σ factors in different bacterial species. Notably, the protein–protein interaction (PPI) study through molecular docking suggested the σ factor could be possibly inhibited by an anti-σ. Finally, a knockout of hrpL in E. mallotivora (ΔEmhrpL) resulted in avirulence in four-month-old papaya plants. These findings have revealed that the hrpL is a necessary element in E. mallotivora pathogenicity and also predicted that the gene can be inhibited by an anti-σ.
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Affiliation(s)
- Amin-Asyraf Tamizi
- Agri-Omics and Bioinformatics Programme, Biotechnology and Nanotechnology Research Centre, Malaysian Agricultural Research and Development Institute Headquarters, Serdang 43400, Selangor, Malaysia; (A.-A.T.); (L.R.); (R.A.-R.)
| | - Norliza Abu-Bakar
- Agri-Omics and Bioinformatics Programme, Biotechnology and Nanotechnology Research Centre, Malaysian Agricultural Research and Development Institute Headquarters, Serdang 43400, Selangor, Malaysia; (A.-A.T.); (L.R.); (R.A.-R.)
- Correspondence: ; Tel.: +60-3-8953-6102
| | - Aimera-Farhana Samsuddin
- School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi 43600, Selangor, Malaysia; (A.-F.S.); (A.-M.A.-M.)
| | - Lina Rozano
- Agri-Omics and Bioinformatics Programme, Biotechnology and Nanotechnology Research Centre, Malaysian Agricultural Research and Development Institute Headquarters, Serdang 43400, Selangor, Malaysia; (A.-A.T.); (L.R.); (R.A.-R.)
| | - Rohaiza Ahmad-Redzuan
- Agri-Omics and Bioinformatics Programme, Biotechnology and Nanotechnology Research Centre, Malaysian Agricultural Research and Development Institute Headquarters, Serdang 43400, Selangor, Malaysia; (A.-A.T.); (L.R.); (R.A.-R.)
| | - Abdul-Munir Abdul-Murad
- School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi 43600, Selangor, Malaysia; (A.-F.S.); (A.-M.A.-M.)
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Construction and Characterization of the Mycobacterium tuberculosis sigE fadD26 Unmarked Double Mutant as a Vaccine Candidate. Infect Immun 2019; 88:IAI.00496-19. [PMID: 31591165 DOI: 10.1128/iai.00496-19] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Accepted: 09/30/2019] [Indexed: 01/17/2023] Open
Abstract
Despite the great increase in the understanding of the biology and pathogenesis of Mycobacterium tuberculosis achieved by the scientific community in recent decades, tuberculosis (TB) still represents one of the major threats to global human health. The only available vaccine (Mycobacterium bovis BCG) protects children from disseminated forms of TB but does not effectively protect adults from the respiratory form of the disease, making the development of new and more-efficacious vaccines against the pulmonary forms of TB a major goal for the improvement of global health. Among the different strategies being developed to reach this goal is the construction of attenuated strains more efficacious and safer than BCG. We recently showed that a sigE mutant of M. tuberculosis was more attenuated and more efficacious than BCG in a mouse model of infection. In this paper, we describe the construction and characterization of an M. tuberculosis sigE fadD26 unmarked double mutant fulfilling the criteria of the Geneva Consensus for entering human clinical trials. The data presented suggest that this mutant is even more attenuated and slightly more efficacious than the previous sigE mutant in different mouse models of infection and is equivalent to BCG in a guinea pig model of infection.
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