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Yadav R, Saini DK. A conserved two-component system senses intracellular iron levels and regulates redox balance in Mycobacterium spp. Microbiol Spectr 2024:e0110624. [PMID: 39315783 DOI: 10.1128/spectrum.01106-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2024] [Accepted: 08/20/2024] [Indexed: 09/25/2024] Open
Abstract
For bacteria, an intricate coordination between sensing and regulating iron levels and managing oxidative stress is required as their levels are tightly interlinked. While various oxidative stress and heme-based redox sensors have been reported for both pathogenic and non-pathogenic bacteria, the mechanisms governing the modulation of intracellular iron levels in response to changes in redox status remain unclear. In this study, a gene-inactivated strain of mycobacterial sensor kinase PdtaS showed dysregulated expression of genes associated with iron metabolism, including Fe-S clusters, NADH dehydrogenases, and iron uptake. The strain showed poor growth in nutrient-limiting conditions, a defect rescuable by heme but not by Fe3+ supplementation. This observation was associated with the PAS domain of the PdtaS sensor kinase. Biochemical and biophysical experiments established heme-binding to the PAS domain and its inhibitory effect on PdtaS auto-kinase activity, suggesting that the absence of heme induces activation of this sensor kinase. Interestingly, despite having an endogenous heme biosynthetic pathway or even external heme supplementation, the ∆pdtaS mutant exhibited persistent low intracellular iron levels concomitant with elevated oxidative stress. Antioxidant supplementation mitigated growth defects, emphasizing the link between oxidative stress, intracellular iron levels, and PdtaS activity. RNA-IP identified key targets associated with redox homeostasis and iron metabolism as targets of the PdtaR response regulator. The study proposes a novel role for the PdtaS-PdtaR TCS in sensing heme, regulation of intracellular iron levels, and redox balance.IMPORTANCEThe research article investigates the intricate interplay between bacteria's ability to take and utilize iron without inducing excess iron's toxic effects, including oxidative stress. The study shows that bacteria achieve this by sensing intracellular iron available as heme through a sensory protein PdtaS, which turns off when heme is in excess and prevents iron uptake and iron efflux. The process shields bacteria from generating Fe-dependent free radicals and allows it to maintain viability. The absence of sensor kinase abrogates all these processes, increasing bacteria susceptibility to ROS and thereby slowing growth. This feature of the sensor kinase PdtaS makes it an attractive co-therapeutic target for tuberculosis therapy, where its inhibition will prevent iron uptake, even in the presence of low iron, thereby halting bacterial proliferation.
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Affiliation(s)
- Rahul Yadav
- Department of Developmental Biology and Genetics, Indian Institute of Science, Bangalore, India
| | - Deepak Kumar Saini
- Department of Developmental Biology and Genetics, Indian Institute of Science, Bangalore, India
- Department of Bioengineering, Indian Institute of Science, Bangalore, India
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2
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Buglino JA, Ozakman Y, Hatch C, Benjamin A, Tan D, Glickman MS. Chalkophore mediated respiratory oxidase flexibility controls M. tuberculosis virulence. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.12.589290. [PMID: 38645185 PMCID: PMC11030325 DOI: 10.1101/2024.04.12.589290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/23/2024]
Abstract
Oxidative phosphorylation has emerged as a critical therapeutic vulnerability of M. tuberculosis, but it is unknown how M. tuberculosis and other pathogens maintain respiration during infection. M. tuberculosis synthesizes diisonitrile lipopeptide chalkophores that chelate copper tightly, but their role in host-pathogen interactions is also unknown. We demonstrate that M. tuberculosis chalkophores maintain the function of the heme-copper bcc:aa3 respiratory oxidase under copper limitation. Chalkophore deficient M. tuberculosis cannot survive, respire to oxygen, or produce ATP under copper deprivation in culture. M. tuberculosis lacking chalkophore biosynthesis is attenuated in mice, a phenotype that is severely exacerbated by loss of the CytBD alternative respiratory oxidase (encoded by cydAB), revealing a multilayered flexibility of the respiratory chain that maintains oxidative phosphorylation during infection. Taken together, these data demonstrate that chalkophores counter host inflicted copper deprivation and highlight that protection of cellular respiration is a critical virulence function in M. tuberculosis.
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Affiliation(s)
- John A. Buglino
- Immunology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, New York 10065 USA
| | - Yaprak Ozakman
- Immunology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, New York 10065 USA
| | - Chad Hatch
- Chemical Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, New York 10065 USA
| | - Anna Benjamin
- Immunology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, New York 10065 USA
| | - Derek Tan
- Chemical Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, New York 10065 USA
- Tri-Institutional Research Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, New York 10065 USA
| | - Michael S. Glickman
- Immunology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, New York 10065 USA
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Yadav M, Sathe J, Teronpi V, Kumar A. Navigating the signaling landscape of Ralstonia solanacearum: a study of bacterial two-component systems. World J Microbiol Biotechnol 2024; 40:153. [PMID: 38564115 DOI: 10.1007/s11274-024-03950-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Accepted: 03/10/2024] [Indexed: 04/04/2024]
Abstract
Ralstonia solanacearum, the bacterium that causes bacterial wilt, is a destructive phytopathogen that can infect over 450 different plant species. Several agriculturally significant crop plants, including eggplant, tomato, pepper, potato, and ginger, are highly susceptible to this plant disease, which has a global impact on crop quality and yield. There is currently no known preventive method that works well for bacterial wilt. Bacteria use two-component systems (TCSs) to sense their environment constantly and react appropriately. This is achieved by an extracellular sensor kinase (SK) capable of sensing a suitable signal and a cytoplasmic response regulator (RR) which gives a downstream response. Moreover, our investigation revealed that R. solanacearum GMI1000 possesses a substantial count of TCSs, specifically comprising 36 RRs and 27 SKs. While TCSs are known targets for various human pathogenic bacteria, such as Salmonella, the role of TCSs in R. solanacearum remains largely unexplored in this context. Notably, numerous inhibitors targeting TCSs have been identified, including GHL (Gyrase, Hsp, and MutL) compounds, Walk inhibitors, and anti-TCS medications like Radicicol. Consequently, the investigation into the involvement of TCSs in virulence and pathogenesis has gained traction; however, further research is imperative to ascertain whether TCSs could potentially supplant conventional anti-wilt therapies. This review delves into the prospective utilization of TCSs as an alternative anti-wilt therapy, focusing on the lethal phytopathogen R. solanacearum.
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Affiliation(s)
- Mohit Yadav
- Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur, Assam, 784028, India
| | - Janhavi Sathe
- Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur, Assam, 784028, India
- Institute for Stem Cell Science and Regenerative Medicine, Bangalore, Karnataka, 560065, India
| | - Valentina Teronpi
- Department of Zoology, Pandit Deendayal Upadhyaya Adarsha Mahavidyalaya, Behali, Biswanath, Assam, 784184, India
| | - Aditya Kumar
- Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur, Assam, 784028, India.
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4
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Wang S, Fang R, Wang H, Li X, Xing J, Li Z, Song N. The role of transcriptional regulators in metal ion homeostasis of Mycobacterium tuberculosis. Front Cell Infect Microbiol 2024; 14:1360880. [PMID: 38529472 PMCID: PMC10961391 DOI: 10.3389/fcimb.2024.1360880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2023] [Accepted: 02/27/2024] [Indexed: 03/27/2024] Open
Abstract
Metal ions are essential trace elements for all living organisms and play critical catalytic, structural, and allosteric roles in many enzymes and transcription factors. Mycobacterium tuberculosis (MTB), as an intracellular pathogen, is usually found in host macrophages, where the bacterium can survive and replicate. One of the reasons why Tuberculosis (TB) is so difficult to eradicate is the continuous adaptation of its pathogen. It is capable of adapting to a wide range of harsh environmental stresses, including metal ion toxicity in the host macrophages. Altering the concentration of metal ions is the common host strategy to limit MTB replication and persistence. This review mainly focuses on transcriptional regulatory proteins in MTB that are involved in the regulation of metal ions such as iron, copper and zinc. The aim is to offer novel insights and strategies for screening targets for TB treatment, as well as for the development and design of new therapeutic interventions.
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Affiliation(s)
- Shuxian Wang
- Key Laboratory of Respiratory Tract Pathogens and Drug Therapy, School of Life Science and Technology, Shandong Second Medical University, Weifang, China
| | - Ren Fang
- Key Laboratory of Respiratory Tract Pathogens and Drug Therapy, School of Life Science and Technology, Shandong Second Medical University, Weifang, China
| | - Hui Wang
- Key Laboratory of Respiratory Tract Pathogens and Drug Therapy, School of Life Science and Technology, Shandong Second Medical University, Weifang, China
| | - Xiaotian Li
- Key Laboratory of Respiratory Tract Pathogens and Drug Therapy, School of Life Science and Technology, Shandong Second Medical University, Weifang, China
| | - Jiayin Xing
- Key Laboratory of Respiratory Tract Pathogens and Drug Therapy, School of Life Science and Technology, Shandong Second Medical University, Weifang, China
| | - Zhaoli Li
- Drug Innovation Research Center, SAFE Pharmaceutical Technology Co. Ltd., Beijing, China
| | - Ningning Song
- Key Laboratory of Respiratory Tract Pathogens and Drug Therapy, School of Life Science and Technology, Shandong Second Medical University, Weifang, China
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Prendergast KA, Nagalingam G, West NP, Triccas JA. Mycobacterium tuberculosis Deficient in PdtaS Cytosolic Histidine Kinase Displays Attenuated Growth and Affords Protective Efficacy against Aerosol M. tuberculosis Infection in Mice. Vaccines (Basel) 2024; 12:50. [PMID: 38250863 PMCID: PMC10821411 DOI: 10.3390/vaccines12010050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 12/20/2023] [Accepted: 12/28/2023] [Indexed: 01/23/2024] Open
Abstract
New control measures are urgently required to control tuberculosis (TB), as the current vaccine, Bacille Calmette-Guérin (BCG), has had a limited impact on disease spread. The identification of virulence mechanisms of Mycobacterium tuberculosis is an important strategy in vaccine design, as it permits the development of strains attenuated for growth that may have vaccine potential. In this report, we determined the role of the PdtaS response regulator in M. tuberculosis virulence and defined the vaccine potential of a pdtaS-deficient strain. Deletion of pdtaS (MtbΔpdtaS) resulted in reduced persistence of M. tuberculosis within mouse organs, which was equivalent to the persistence of the BCG vaccine in the lung and liver of infected mice. However, the generation of effector CD4+ and CD8+ T cells (CD44+CD62LloKLRG1+) was similar between wild-type M. tuberculosis and MtbΔpdtaS and greater than that elicited by BCG. Heightened immunity induced by MtbΔpdtaS compared to BCG was also observed by analysis of antigen-specific IFN-γ-secreting T cell responses induced by vaccination. MtbΔpdtaS displayed improved protection against aerosol M. tuberculosis compared to BCG, which was most apparent in the lung at 20 weeks post-infection. These results suggest that the deletion of the PdtaS response regulator warrants further appraisal as a tool to combat TB in humans.
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Affiliation(s)
- Kelly A. Prendergast
- Sydney Infectious Diseases Institute (Sydney ID), Faculty of Medicine and Health, The University of Sydney, Camperdown, NSW 2006, Australia; (K.A.P.); (G.N.)
- School of Medical Sciences, The University of Sydney, Camperdown, NSW 2006, Australia
| | - Gayathri Nagalingam
- Sydney Infectious Diseases Institute (Sydney ID), Faculty of Medicine and Health, The University of Sydney, Camperdown, NSW 2006, Australia; (K.A.P.); (G.N.)
- School of Medical Sciences, The University of Sydney, Camperdown, NSW 2006, Australia
| | - Nicholas P. West
- Australian Infectious Disease Research Centre, School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD 4072, Australia;
| | - James A. Triccas
- Sydney Infectious Diseases Institute (Sydney ID), Faculty of Medicine and Health, The University of Sydney, Camperdown, NSW 2006, Australia; (K.A.P.); (G.N.)
- School of Medical Sciences, The University of Sydney, Camperdown, NSW 2006, Australia
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6
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Li Y, Kong X, Li Y, Tao N, Hou Y, Wang T, Li Y, Han Q, Liu Y, Li H. Association between two-component systems gene mutation and Mycobacterium tuberculosis transmission revealed by whole genome sequencing. BMC Genomics 2023; 24:718. [PMID: 38017383 PMCID: PMC10683263 DOI: 10.1186/s12864-023-09788-2] [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: 08/04/2023] [Accepted: 11/06/2023] [Indexed: 11/30/2023] Open
Abstract
BACKGROUND Two-component systems (TCSs) assume a pivotal function in Mycobacterium tuberculosis (M.tuberculosis) growth. However, the exact regulatory mechanism of this system needs to be elucidated, and only a few studies have investigated the effect of gene mutations within TCSs on M.tuberculosis transmission. This research explored the relationship between TCSs gene mutation and the global transmission of (M.tuberculosis). RESULTS A total of 13531 M.tuberculosis strains were enrolled in the study. Most of the M.tuberculosis strains belonged to lineage4 (n=6497,48.0%), followed by lineage2 (n=5136,38.0%). Our results showed that a total of 36 single nucleotide polymorphisms (SNPs) were positively correlated with clustering of lineage2, such as Rv0758 (phoR, C820G), Rv1747(T1102C), and Rv1057(C1168T). A total of 30 SNPs showed positive correlation with clustering of lineage4, such as phoR(C182A, C1184G, C662T, T758G), Rv3764c (tcrY, G1151T), and Rv1747 C20T. A total of 19 SNPs were positively correlated with cross-country transmission of lineage2, such as phoR A575C, Rv1028c (kdpD, G383T, G1246C), and Rv1057 G817T. A total of 41 SNPs were positively correlated with cross-country transmission of lineage4, such as phoR(T758G, T327G, C284G), kdpD(G1755A, G625C), Rv1057 C980T, and Rv1747 T373G. CONCLUSIONS Our study identified that SNPs in genes of two-component systems were related to the transmission of M. tuberculosis. This finding adds another layer of complexity to M. tuberculosis virulence and provides insight into future research that will help to elucidate a novel mechanism of M. tuberculosis pathogenicity.
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Affiliation(s)
- Yameng Li
- Shandong University of Traditional Chinese Medicine, Jinan, Shandong, 250014, People's Republic of China
| | - Xianglong Kong
- Artificial Intelligence Institute, Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, 250011, People's Republic of China
| | - Yifan Li
- Department of Respiratory and Critical Care Medicine, The Third Affiliated Hospital of Shandong First Medical University (Affiliated Hospital of Shandong Academy of Medical Sciences), Jinan, Shandong, 250031, People's Republic of China
| | - Ningning Tao
- Department of Respiratory and Critical Care Medicine, Shandong Provincial Hospital Affiliated to Shandong University, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jingwuweiqi Road, Huaiyin District, Jinan, Shandong, 250021, People's Republic of China
| | - Yawei Hou
- Shandong University of Traditional Chinese Medicine, Jinan, Shandong, 250014, People's Republic of China
| | - Tingting Wang
- Shandong University of Traditional Chinese Medicine, Jinan, Shandong, 250014, People's Republic of China
| | - Yingying Li
- Shandong University of Traditional Chinese Medicine, Jinan, Shandong, 250014, People's Republic of China
| | - Qilin Han
- Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong, 250117, People's Republic of China
| | - Yao Liu
- Department of Respiratory and Critical Care Medicine, Shandong Provincial Hospital Affiliated to Shandong University, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jingwuweiqi Road, Huaiyin District, Jinan, Shandong, 250021, People's Republic of China.
| | - Huaichen Li
- Shandong University of Traditional Chinese Medicine, Jinan, Shandong, 250014, People's Republic of China.
- Department of Respiratory and Critical Care Medicine, Shandong Provincial Hospital Affiliated to Shandong University, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jingwuweiqi Road, Huaiyin District, Jinan, Shandong, 250021, People's Republic of China.
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7
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Yang J, Zhang L, Qiao W, Luo Y. Mycobacterium tuberculosis: Pathogenesis and therapeutic targets. MedComm (Beijing) 2023; 4:e353. [PMID: 37674971 PMCID: PMC10477518 DOI: 10.1002/mco2.353] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 07/31/2023] [Accepted: 08/03/2023] [Indexed: 09/08/2023] Open
Abstract
Tuberculosis (TB) remains a significant public health concern in the 21st century, especially due to drug resistance, coinfection with diseases like immunodeficiency syndrome (AIDS) and coronavirus disease 2019, and the lengthy and costly treatment protocols. In this review, we summarize the pathogenesis of TB infection, therapeutic targets, and corresponding modulators, including first-line medications, current clinical trial drugs and molecules in preclinical assessment. Understanding the mechanisms of Mycobacterium tuberculosis (Mtb) infection and important biological targets can lead to innovative treatments. While most antitubercular agents target pathogen-related processes, host-directed therapy (HDT) modalities addressing immune defense, survival mechanisms, and immunopathology also hold promise. Mtb's adaptation to the human host involves manipulating host cellular mechanisms, and HDT aims to disrupt this manipulation to enhance treatment effectiveness. Our review provides valuable insights for future anti-TB drug development efforts.
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Affiliation(s)
- Jiaxing Yang
- Center of Infectious Diseases and State Key Laboratory of Biotherapy, West China HospitalSichuan UniversityChengduChina
| | - Laiying Zhang
- Center of Infectious Diseases and State Key Laboratory of Biotherapy, West China HospitalSichuan UniversityChengduChina
| | - Wenliang Qiao
- Department of Thoracic Surgery, West China HospitalSichuan UniversityChengduSichuanChina
- Lung Cancer Center, West China HospitalSichuan UniversityChengduSichuanChina
| | - Youfu Luo
- Center of Infectious Diseases and State Key Laboratory of Biotherapy, West China HospitalSichuan UniversityChengduChina
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Limón G, Samhadaneh NM, Pironti A, Darwin KH. Aldehyde accumulation in Mycobacterium tuberculosis with defective proteasomal degradation results in copper sensitivity. mBio 2023; 14:e0036323. [PMID: 37350636 PMCID: PMC10470581 DOI: 10.1128/mbio.00363-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2023] [Accepted: 04/17/2023] [Indexed: 06/24/2023] Open
Abstract
Mycobacterium tuberculosis is a major human pathogen and the causative agent of tuberculosis disease. M. tuberculosis is able to persist in the face of host-derived antimicrobial molecules nitric oxide (NO) and copper (Cu). However, M. tuberculosis with defective proteasome activity is highly sensitive to NO and Cu, making the proteasome an attractive target for drug development. Previous work linked NO susceptibility with the accumulation of para-hydroxybenzaldehyde (pHBA) in M. tuberculosis mutants with defective proteasomal degradation. In this study, we found that pHBA accumulation was also responsible for Cu sensitivity in these strains. We showed that exogenous addition of pHBA to wild-type M. tuberculosis cultures sensitized bacteria to Cu to a degree similar to that of a proteasomal degradation mutant. We determined that pHBA reduced the production and function of critical Cu resistance proteins of the regulated in copper repressor (RicR) regulon. Furthermore, we extended these Cu-sensitizing effects to an aldehyde that M. tuberculosis may face within the macrophage. Collectively, this study is the first to mechanistically propose how aldehydes can render M. tuberculosis susceptible to an existing host defense and could support a broader role for aldehydes in controlling M. tuberculosis infections. IMPORTANCE M. tuberculosis is a leading cause of death by a single infectious agent, causing 1.5 million deaths annually. An effective vaccine for M. tuberculosis infections is currently lacking, and prior infection does not typically provide robust immunity to subsequent infections. Nonetheless, immunocompetent humans can control M. tuberculosis infections for decades. For these reasons, a clear understanding of how mammalian immunity inhibits mycobacterial growth is warranted. In this study, we show aldehydes can increase M. tuberculosis susceptibility to copper, an established antibacterial metal used by immune cells to control M. tuberculosis and other microbes. Given that activated macrophages produce increased amounts of aldehydes during infection, we propose host-derived aldehydes may help control bacterial infections, making aldehydes a previously unappreciated antimicrobial defense.
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Affiliation(s)
- Gina Limón
- Department of Microbiology, New York University Grossman School of Medicine, New York, New York, USA
| | - Nora M. Samhadaneh
- Department of Microbiology, New York University Grossman School of Medicine, New York, New York, USA
- Antimicrobial-Resistant Pathogens Program, New York University Grossman School of Medicine, New York, New York, USA
- Microbial Computational Genomic Core Lab, New York University Grossman School of Medicine, New York, New York, USA
| | - Alejandro Pironti
- Department of Microbiology, New York University Grossman School of Medicine, New York, New York, USA
- Antimicrobial-Resistant Pathogens Program, New York University Grossman School of Medicine, New York, New York, USA
- Microbial Computational Genomic Core Lab, New York University Grossman School of Medicine, New York, New York, USA
| | - K. Heran Darwin
- Department of Microbiology, New York University Grossman School of Medicine, New York, New York, USA
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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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10
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Sankhe GD, Raja R, Singh DP, Bheemireddy S, Rana S, Athira PJ, Dixit NM, Saini DK. Sequestration of histidine kinases by non-cognate response regulators establishes a threshold level of stimulation for bacterial two-component signaling. Nat Commun 2023; 14:4483. [PMID: 37491529 PMCID: PMC10368727 DOI: 10.1038/s41467-023-40095-2] [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: 05/05/2020] [Accepted: 07/12/2023] [Indexed: 07/27/2023] Open
Abstract
Bacterial two-component systems (TCSs) consist of a sensor histidine kinase (HK) that perceives a specific signal, and a cognate response regulator (RR) that modulates the expression of target genes. Positive autoregulation improves TCS sensitivity to stimuli, but may trigger disproportionately large responses to weak signals, compromising bacterial fitness. Here, we combine experiments and mathematical modelling to reveal a general design that prevents such disproportionate responses: phosphorylated HKs (HK~Ps) can be sequestered by non-cognate RRs. We study five TCSs of Mycobacterium tuberculosis and find, for all of them, non-cognate RRs that show higher affinity than cognate RRs for HK~Ps. Indeed, in vitro assays show that HK~Ps preferentially bind higher affinity non-cognate RRs and get sequestered. Mathematical modelling indicates that this sequestration would introduce a 'threshold' stimulus strength for eliciting responses, thereby preventing responses to weak signals. Finally, we construct tunable expression systems in Mycobacterium bovis BCG to show that higher affinity non-cognate RRs suppress responses in vivo.
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Affiliation(s)
- Gaurav D Sankhe
- Centre for Biosystems Science and Engineering, Indian Institute of Science, Bengaluru, India
| | - Rubesh Raja
- Department of Chemical Engineering, Indian Institute of Science, Bengaluru, India
| | - Devendra Pratap Singh
- Department of Developmental Biology and Genetics, Indian Institute of Science, Bengaluru, India
| | - Sneha Bheemireddy
- Molecular Biophysics Unit, Indian Institute of Science, Bengaluru, India
| | - Subinoy Rana
- Materials Research Centre, Indian Institute of Science, Bengaluru, India
| | - P J Athira
- Department of Developmental Biology and Genetics, Indian Institute of Science, Bengaluru, India
| | - Narendra M Dixit
- Centre for Biosystems Science and Engineering, Indian Institute of Science, Bengaluru, India.
- Department of Chemical Engineering, Indian Institute of Science, Bengaluru, India.
| | - Deepak Kumar Saini
- Centre for Biosystems Science and Engineering, Indian Institute of Science, Bengaluru, India.
- Department of Developmental Biology and Genetics, Indian Institute of Science, Bengaluru, India.
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11
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Kristensen SS, Diep DB, Kjos M, Mathiesen G. The role of site-2-proteases in bacteria: a review on physiology, virulence, and therapeutic potential. MICROLIFE 2023; 4:uqad025. [PMID: 37223736 PMCID: PMC10202637 DOI: 10.1093/femsml/uqad025] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 04/21/2023] [Accepted: 05/02/2023] [Indexed: 05/25/2023]
Abstract
Site-2-proteases are a class of intramembrane proteases involved in regulated intramembrane proteolysis. Regulated intramembrane proteolysis is a highly conserved signaling mechanism that commonly involves sequential digestion of an anti-sigma factor by a site-1- and site-2-protease in response to external stimuli, resulting in an adaptive transcriptional response. Variation of this signaling cascade continues to emerge as the role of site-2-proteases in bacteria continues to be explored. Site-2-proteases are highly conserved among bacteria and play a key role in multiple processes, including iron uptake, stress response, and pheromone production. Additionally, an increasing number of site-2-proteases have been found to play a pivotal role in the virulence properties of multiple human pathogens, such as alginate production in Pseudomonas aeruginosa, toxin production in Vibrio cholerae, resistance to lysozyme in enterococci and antimicrobials in several Bacillus spp, and cell-envelope lipid composition in Mycobacterium tuberculosis. The prominent role of site-2-proteases in bacterial pathogenicity highlights the potential of site-2-proteases as novel targets for therapeutic intervention. In this review, we summarize the role of site-2-proteases in bacterial physiology and virulence, as well as evaluate the therapeutic potential of site-2-proteases.
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Affiliation(s)
- Sofie S Kristensen
- Faculty of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences (NMBU), 1433 Ås, Norway
| | | | - Morten Kjos
- Corresponding author. NMBU, P.O. Box 5003, 1433 Ås, Norway. E-mail:
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Diisonitrile Lipopeptides Mediate Resistance to Copper Starvation in Pathogenic Mycobacteria. mBio 2022; 13:e0251322. [PMID: 36197089 PMCID: PMC9600254 DOI: 10.1128/mbio.02513-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacterial pathogens and their hosts engage in intense competition for critical nutrients during infection, including metals such as iron, copper, and zinc. Some metals are limited by the host, and some are deployed by the host as antimicrobials. To counter metal limitation, pathogens deploy high-affinity metal acquisition systems, best exemplified by siderophores to acquire iron. Although pathogen strategies to resist the toxic effects of high Cu have been elucidated, the role of Cu starvation and the existence of Cu acquisition systems are less well characterized. In this study, we examined the role of diisonitrile chalkophores of pathogenic mycobacteria, synthesized by the enzymes encoded by the virulence-associated nrp gene cluster, in metal acquisition. nrp gene cluster expression is strongly induced by starvation or chelation of Cu but not starvation of Zn or excess Cu. Mycobacterium tuberculosis and Mycobacterium marinum strains lacking the nrp-encoded nonribosomal peptide sythetase, the fadD10 adenylate-forming enzyme, or the uncharacterized upstream gene ppe1 are all sensitized to Cu, but not Zn, starvation. This low Cu sensitivity is rescued by genetic complementation or by provision of a synthetic diisonitrile chalkophore. These data demonstrate that diisonitrile lipopeptides in mycobacteria are chalkophores that facilitate survival under Cu-limiting conditions and suggest that Cu starvation is a relevant stress for M. tuberculosis in the host.
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13
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Stupar M, Furness J, De Voss CJ, Tan L, West NP. Two-component sensor histidine kinases of Mycobacterium tuberculosis: beacons for niche navigation. Mol Microbiol 2022; 117:973-985. [PMID: 35338720 PMCID: PMC9321153 DOI: 10.1111/mmi.14899] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 03/12/2022] [Accepted: 03/22/2022] [Indexed: 11/27/2022]
Abstract
Intracellular bacterial pathogens such as Mycobacterium tuberculosis are remarkably adept at surviving within a host, employing a variety of mechanisms to counteract host defenses and establish a protected niche. Constant surveying of the environment is key for pathogenic mycobacteria to discern their immediate location and coordinate the expression of genes necessary for adaptation. Two‐component systems efficiently perform this role, typically comprised of a transmembrane sensor kinase and a cytoplasmic response regulator. In this review, we describe the role of two‐component systems in bacterial pathogenesis, focusing predominantly on the role of sensor kinases of M. tuberculosis. We highlight important features of sensor kinases in mycobacterial infection, discuss ways in which these signaling proteins sense and respond to environments, and how this is attuned to their intracellular lifestyle. Finally, we discuss recent studies which have identified and characterized inhibitors of two‐component sensor kinases toward establishing a new strategy in anti‐mycobacterial therapy.
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Affiliation(s)
- Miljan Stupar
- School of Chemistry and Molecular Biosciences, Australian Infectious Disease Research Centre, University of Queensland, Brisbane, 4072, Australia
| | - Juanelle Furness
- School of Chemistry and Molecular Biosciences, Australian Infectious Disease Research Centre, University of Queensland, Brisbane, 4072, Australia
| | - Christopher J De Voss
- School of Chemistry and Molecular Biosciences, Australian Infectious Disease Research Centre, University of Queensland, Brisbane, 4072, Australia
| | - Lendl Tan
- School of Chemistry and Molecular Biosciences, Australian Infectious Disease Research Centre, University of Queensland, Brisbane, 4072, Australia
| | - Nicholas P West
- School of Chemistry and Molecular Biosciences, Australian Infectious Disease Research Centre, University of Queensland, Brisbane, 4072, Australia
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Cai Z, Yang F, Shao X, Yue Z, Li Z, Song Y, Pan X, Jin Y, Cheng Z, Ha UH, Feng J, Yang L, Deng X, Wu W, Bai F. ECF Sigma Factor HxuI Is Critical for In Vivo Fitness of Pseudomonas aeruginosa during Infection. Microbiol Spectr 2022; 10:e0162021. [PMID: 35044199 PMCID: PMC8768829 DOI: 10.1128/spectrum.01620-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Accepted: 01/04/2022] [Indexed: 11/22/2022] Open
Abstract
The opportunistic pathogen Pseudomonas aeruginosa often adapts to its host environment and causes recurrent nosocomial infections. The extracytoplasmic function (ECF) sigma factor enables bacteria to alter their gene expression in response to host environmental stimuli. Here, we report an ECF sigma factor, HxuI, which is rapidly induced once P. aeruginosa encounters the host. Host stresses such as iron limitation, oxidative stress, low oxygen, and nitric oxide induce the expression of hxuI. By combining RNA-seq and promoter-lacZ reporter fusion analysis, we reveal that HxuI can activate the expression of diverse metabolic and virulence pathways which are critical to P. aeruginosa infections, including iron acquisition, denitrification, pyocyanin synthesis, and bacteriocin production. Most importantly, overexpression of the hxuI in the laboratory strain PAO1 promotes its colonization in both murine lung and subcutaneous infections. Together, our findings show that HxuI, a key player in host stress-response, controls the in vivo adaptability and virulence of P. aeruginosa during infection. IMPORTANCE P. aeruginosa has a strong ability to adapt to diverse environments, making it capable of causing recurrent and multisite infections in clinics. Understanding host adaptive mechanisms plays an important guiding role in the development of new anti-infective agents. Here, we demonstrate that an ECFσ factor of P. aeruginosa response to the host-inflicted stresses, which promotes the bacterial in vivo fitness and pathogenicity. Furthermore, our findings may help explain the emergence of highly transmissible strains of P. aeruginosa and the acute exacerbations during chronic infections.
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Affiliation(s)
- Zeqiong Cai
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
| | - Fan Yang
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
| | - Xiaolong Shao
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China
| | - Zhuo Yue
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
| | - Zhenpeng Li
- School of Laboratory Medicine, Key Laboratory of Clinical Laboratory Diagnostics in Universities of Shandong, Weifang Medical University, Weifang, Shandong, China
| | - Yuqin Song
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Xiaolei Pan
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
| | - Yongxin Jin
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
| | - Zhihui Cheng
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
| | - Un-Hwan Ha
- Department of Biotechnology and Bioinformatics, Korea University, Sejong, Republic of Korea
| | - Jie Feng
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Liang Yang
- School of Medicine, Southern University of Science and Technology (SUSTec), Shenzhen, China
| | - Xin Deng
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China
| | - Weihui Wu
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
| | - Fang Bai
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
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