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Mediati DG, Blair TA, Costas A, Monahan LG, Söderström B, Charles IG, Duggin IG. Genetic requirements for uropathogenic E. coli proliferation in the bladder cell infection cycle. mSystems 2024:e0038724. [PMID: 39287381 DOI: 10.1128/msystems.00387-24] [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: 03/19/2024] [Accepted: 08/09/2024] [Indexed: 09/19/2024] Open
Abstract
Uropathogenic Escherichia coli (UPEC) requires an adaptable physiology to survive the wide range of environments experienced in the host, including gut and urinary tract surfaces. To identify UPEC genes required during intracellular infection, we developed a transposon-directed insertion-site sequencing approach for cellular infection models and searched for genes in a library of ~20,000 UTI89 transposon-insertion mutants that are specifically required at the distinct stages of infection of cultured bladder epithelial cells. Some of the bacterial functional requirements apparent in host bladder cell growth overlapped with those for M9-glycerol, notably nutrient utilization, polysaccharide and macromolecule precursor biosynthesis, and cell envelope stress tolerance. Two genes implicated in the intracellular bladder cell infection stage were confirmed through independent gene deletion studies: neuC (sialic acid capsule biosynthesis) and hisF (histidine biosynthesis). Distinct sets of UPEC genes were also implicated in bacterial dispersal, where UPEC erupts from bladder cells in highly filamentous or motile forms upon exposure to human urine, and during recovery from infection in a rich medium. We confirm that the dedD gene linked to septal peptidoglycan remodeling is required during UPEC dispersal from human bladder cells and may help stabilize cell division or the cell wall during envelope stress created by host cells. Our findings support a view that the host intracellular environment and infection cycle are multi-nutrient limited and create stress that demands an array of biosynthetic, cell envelope integrity, and biofilm-related functions of UPEC. IMPORTANCE Urinary tract infections (UTIs) are one of the most frequent infections worldwide. Uropathogenic Escherichia coli (UPEC), which accounts for ~80% of UTIs, must rapidly adapt to highly variable host environments, such as the gut, bladder sub-surface, and urine. In this study, we searched for UPEC genes required for bacterial growth and survival throughout the cellular infection cycle. Genes required for de novo synthesis of biomolecules and cell envelope integrity appeared to be important, and other genes were also implicated in bacterial dispersal and recovery from infection of cultured bladder cells. With further studies of individual gene function, their potential as therapeutic targets may be realized. This study expands knowledge of the UTI cycle and establishes an approach to genome-wide functional analyses of stage-resolved microbial infections.
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Affiliation(s)
- Daniel G Mediati
- Australian Institute for Microbiology and Infection, University of Technology Sydney, Ultimo, Australia
| | - Tamika A Blair
- Australian Institute for Microbiology and Infection, University of Technology Sydney, Ultimo, Australia
| | - Ariana Costas
- Australian Institute for Microbiology and Infection, University of Technology Sydney, Ultimo, Australia
- Institut Cochin, INSERM U1016, Université de Paris, Paris, France
| | - Leigh G Monahan
- Australian Institute for Microbiology and Infection, University of Technology Sydney, Ultimo, Australia
| | - Bill Söderström
- Australian Institute for Microbiology and Infection, University of Technology Sydney, Ultimo, Australia
| | - Ian G Charles
- Quadram Institute Bioscience, Norwich Research Park, Norwich, United Kingdom
- Norwich Medical School, University of East Anglia, Norwich Research Park, Norwich, United Kingdom
| | - Iain G Duggin
- Australian Institute for Microbiology and Infection, University of Technology Sydney, Ultimo, Australia
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2
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Hall KT, Kenedy MR, Johnson DK, Hefty PS, Akins DR. A conserved C-terminal domain of TamB interacts with multiple BamA POTRA domains in Borreliella burgdorferi. PLoS One 2024; 19:e0304839. [PMID: 39208212 PMCID: PMC11361582 DOI: 10.1371/journal.pone.0304839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Accepted: 05/20/2024] [Indexed: 09/04/2024] Open
Abstract
Lyme disease is the leading tick-borne infection in the United States, caused by the pathogenic spirochete Borreliella burgdorferi, formerly known as Borrelia burgdorferi. Diderms, or bacteria with dual-membrane ultrastructure, such as B. burgdorferi, have multiple methods of transporting and integrating outer membrane proteins (OMPs). Most integral OMPs are transported through the β-barrel assembly machine (BAM) complex. This complex consists of the channel-forming OMP BamA and accessory lipoproteins that interact with the five periplasmic, polypeptide transport-associated (POTRA) domains of BamA. Another system, the translocation and assembly module (TAM) system, has also been implicated in OMP assembly and export. The TAM system consists of two proteins, the BamA paralog TamA which has three POTRA domains and the inner membrane protein TamB. TamB is characterized by a C-terminal DUF490 domain that interacts with the POTRA domains of TamA. Interestingly, while TamB is found in almost all diderms, including B. burgdorferi, TamA is found almost exclusively in Proteobacteria. This strongly suggests a TamA-independent role of TamB in most diderms. We previously demonstrated that BamA interacts with TamB in B. burgdorferi and hypothesized that this is facilitated by the BamA POTRA domains interacting with the TamB DUF490 domain. In this study, we utilized protein-protein co-purification assays to empirically demonstrate that the B. burgdorferi TamB DUF490 domain interacts with BamA POTRA2 and POTRA3. We also observed that the DUF490 domain of TamB interacts with the accessory lipoprotein BamB. To examine if the BamA-TamB interaction is more ubiquitous among diderms, we examined BamA-TamB interactions in Salmonella enterica serovar Typhimurium (St). Interestingly, even though St encodes a TamA protein that interacts with TamB, we observed that the TamB DUF490 of St interacts with BamA in this organism. Our combined findings strongly suggest that the TamB-BamA interaction occurs independent of the TamA component of the TAM protein export system.
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Affiliation(s)
- Kari T. Hall
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Melisha R. Kenedy
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - David K. Johnson
- Chemical Computational Biology Core and the Molecular Graphics and Modeling Laboratory, University of Kansas, Lawrence, Kansas, United States of America
| | - P. Scott Hefty
- Department of Molecular Biosciences and the Center for Chemical Biology of Infectious Disease, University of Kansas, Lawrence, Kansas, United States of America
| | - Darrin R. Akins
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
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3
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McDonald K, Rodriguez A, Muthukrishnan G. Humanized Mouse Models of Bacterial Infections. Antibiotics (Basel) 2024; 13:640. [PMID: 39061322 PMCID: PMC11273811 DOI: 10.3390/antibiotics13070640] [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: 06/05/2024] [Revised: 07/02/2024] [Accepted: 07/06/2024] [Indexed: 07/28/2024] Open
Abstract
Bacterial infections continue to represent a significant healthcare burden worldwide, causing considerable mortality and morbidity every year. The emergence of multidrug-resistant bacterial strains continues to rise, posing serious risks to controlling global disease outbreaks. To develop novel and more effective treatment and vaccination programs, there is a need for clinically relevant small animal models. Since multiple bacterial species have human-specific tropism for numerous virulence factors and toxins, conventional mouse models do not fully represent human disease. Several human disease characteristic phenotypes, such as lung granulomas in the case of Mycobacterium tuberculosis infections, are absent in standard mouse models. Alternatively, certain pathogens, such as Salmonella enterica serovar typhi and Staphylococcus aureus, can be well tolerated in mice and cleared quickly. To address this, multiple groups have developed humanized mouse models and observed enhanced susceptibility to infection and a more faithful recapitulation of human disease. In the last two decades, multiple humanized mouse models have been developed to attempt to recapitulate the human immune system in a small animal model. In this review, we first discuss the history of immunodeficient mice that has enabled the engraftment of human tissue and the engraftment methods currently used in the field. We then highlight how humanized mouse models successfully uncovered critical human immune responses to various bacterial infections, including Salmonella enterica serovar Typhi, Mycobacterium tuberculosis, and Staphylococcus aureus.
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Affiliation(s)
- Katya McDonald
- Center for Musculoskeletal Research, Department of Orthopaedics, University of Rochester Medical Center, 601 Elmwood Avenue, Box 665, Rochester, NY 14642, USA
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Adryiana Rodriguez
- Center for Musculoskeletal Research, Department of Orthopaedics, University of Rochester Medical Center, 601 Elmwood Avenue, Box 665, Rochester, NY 14642, USA
| | - Gowrishankar Muthukrishnan
- Center for Musculoskeletal Research, Department of Orthopaedics, University of Rochester Medical Center, 601 Elmwood Avenue, Box 665, Rochester, NY 14642, USA
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, USA
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4
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Wang BX, Leshchiner D, Luo L, Tuncel M, Hokamp K, Hinton JCD, Monack DM. High-throughput fitness experiments reveal specific vulnerabilities of human-adapted Salmonella during stress and infection. Nat Genet 2024; 56:1288-1299. [PMID: 38831009 PMCID: PMC11176087 DOI: 10.1038/s41588-024-01779-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Accepted: 04/25/2024] [Indexed: 06/05/2024]
Abstract
Salmonella enterica is comprised of genetically distinct 'serovars' that together provide an intriguing model for exploring the genetic basis of pathogen evolution. Although the genomes of numerous Salmonella isolates with broad variations in host range and human disease manifestations have been sequenced, the functional links between genetic and phenotypic differences among these serovars remain poorly understood. Here, we conduct high-throughput functional genomics on both generalist (Typhimurium) and human-restricted (Typhi and Paratyphi A) Salmonella at unprecedented scale in the study of this enteric pathogen. Using a comprehensive systems biology approach, we identify gene networks with serovar-specific fitness effects across 25 host-associated stresses encountered at key stages of human infection. By experimentally perturbing these networks, we characterize previously undescribed pseudogenes in human-adapted Salmonella. Overall, this work highlights specific vulnerabilities encoded within human-restricted Salmonella that are linked to the degradation of their genomes, shedding light into the evolution of this enteric pathogen.
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Affiliation(s)
- Benjamin X Wang
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA
| | | | - Lijuan Luo
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK
| | - Miles Tuncel
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA
| | - Karsten Hokamp
- Department of Genetics, School of Genetics and Microbiology, Smurfit Institute of Genetics, Trinity College Dublin, Dublin, Ireland
| | - Jay C D Hinton
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK
| | - Denise M Monack
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA.
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5
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Stepien TA, Singletary LA, Guerra FE, Karlinsey JE, Libby SJ, Jaslow SL, Gaggioli MR, Gibbs KD, Ko DC, Brehm MA, Greiner DL, Shultz LD, Fang FC. Nuclear factor kappa B-dependent persistence of Salmonella Typhi and Paratyphi in human macrophages. mBio 2024; 15:e0045424. [PMID: 38497655 PMCID: PMC11005419 DOI: 10.1128/mbio.00454-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Accepted: 02/21/2024] [Indexed: 03/19/2024] Open
Abstract
Salmonella serovars Typhi and Paratyphi cause a prolonged illness known as enteric fever, whereas other serovars cause acute gastroenteritis. Mechanisms responsible for the divergent clinical manifestations of nontyphoidal and enteric fever Salmonella infections have remained elusive. Here, we show that S. Typhi and S. Paratyphi A can persist within human macrophages, whereas S. Typhimurium rapidly induces apoptotic macrophage cell death that is dependent on Salmonella pathogenicity island 2 (SPI2). S. Typhi and S. Paratyphi A lack 12 specific SPI2 effectors with pro-apoptotic functions, including nine that target nuclear factor κB (NF-κB). Pharmacologic inhibition of NF-κB or heterologous expression of the SPI2 effectors GogA or GtgA restores apoptosis of S. Typhi-infected macrophages. In addition, the absence of the SPI2 effector SarA results in deficient signal transducer and activator of transcription 1 (STAT1) activation and interleukin 12 production, leading to impaired TH1 responses in macrophages and humanized mice. The absence of specific nontyphoidal SPI2 effectors may allow S. Typhi and S. Paratyphi A to cause chronic infections. IMPORTANCE Salmonella enterica is a common cause of gastrointestinal infections worldwide. The serovars Salmonella Typhi and Salmonella Paratyphi A cause a distinctive systemic illness called enteric fever, whose pathogenesis is incompletely understood. Here, we show that enteric fever Salmonella serovars lack 12 specific virulence factors possessed by nontyphoidal Salmonella serovars, which allow the enteric fever serovars to persist within human macrophages. We propose that this fundamental difference in the interaction of Salmonella with human macrophages is responsible for the chronicity of typhoid and paratyphoid fever, suggesting that targeting the nuclear factor κB (NF-κB) complex responsible for macrophage survival could facilitate the clearance of persistent bacterial infections.
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Affiliation(s)
- Taylor A. Stepien
- Department of Global Health, University of Washington, Seattle, Washington, USA
| | | | - Fermin E. Guerra
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, Washington, USA
| | - Joyce E. Karlinsey
- Department of Microbiology, University of Washington, Seattle, Washington, USA
| | - Stephen J. Libby
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, Washington, USA
| | - Sarah L. Jaslow
- Department of Molecular Genetics and Microbiology, Duke University, Durham, North Carolina, USA
| | - Margaret R. Gaggioli
- Department of Molecular Genetics and Microbiology, Duke University, Durham, North Carolina, USA
| | - Kyle D. Gibbs
- Department of Molecular Genetics and Microbiology, Duke University, Durham, North Carolina, USA
| | - Dennis C. Ko
- Department of Molecular Genetics and Microbiology, Duke University, Durham, North Carolina, USA
| | - Michael A. Brehm
- Department of Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Dale L. Greiner
- Department of Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | | | - Ferric C. Fang
- Department of Global Health, University of Washington, Seattle, Washington, USA
- Department of Microbiology, University of Washington, Seattle, Washington, USA
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, Washington, USA
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6
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Stromberg ZR, Phillips SMB, Omberg KM, Hess BM. High-throughput functional trait testing for bacterial pathogens. mSphere 2023; 8:e0031523. [PMID: 37702517 PMCID: PMC10597404 DOI: 10.1128/msphere.00315-23] [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] [Indexed: 09/14/2023] Open
Abstract
Functional traits are characteristics that affect the fitness and metabolic function of a microorganism. There is growing interest in using high-throughput methods to characterize bacterial pathogens based on functional virulence traits. Traditional methods that phenotype a single organism for a single virulence trait can be time consuming and labor intensive. Alternatively, machine learning of whole-genome sequences (WGS) has shown some success in predicting virulence. However, relying solely on WGS can miss functional traits, particularly for organisms lacking classical virulence factors. We propose that high-throughput assays for functional virulence trait identification should become a prominent method of characterizing bacterial pathogens on a population scale. This work is critical as we move from compiling lists of bacterial species associated with disease to pathogen-agnostic approaches capable of detecting novel microbes. We discuss six key areas of functional trait testing and how advancing high-throughput methods could provide a greater understanding of pathogens.
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Affiliation(s)
- Zachary R. Stromberg
- Chemical and Biological Signatures Group, Pacific Northwest National Laboratory, Richland, Washington, USA
| | - Shelby M. B. Phillips
- Chemical and Biological Signatures Group, Pacific Northwest National Laboratory, Richland, Washington, USA
| | - Kristin M. Omberg
- Chemical and Biological Signatures Group, Pacific Northwest National Laboratory, Richland, Washington, USA
| | - Becky M. Hess
- Chemical and Biological Signatures Group, Pacific Northwest National Laboratory, Richland, Washington, USA
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7
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Thurston TLM, Holden DW. The Salmonella Typhi SPI-2 injectisome enigma. MICROBIOLOGY (READING, ENGLAND) 2023; 169:001405. [PMID: 37862087 PMCID: PMC10634361 DOI: 10.1099/mic.0.001405] [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: 08/29/2023] [Accepted: 10/11/2023] [Indexed: 10/21/2023]
Abstract
The Salmonella pathogenicity island 2 (SPI-2)-encoded type III secretion system (injectisome) is assembled following uptake of bacteria into vacuoles in mammalian cells. The injectisome translocates virulence proteins (effectors) into infected cells. Numerous studies have established the requirement for a functional SPI-2 injectisome for growth of Salmonella Typhimurium in mouse macrophages, but the results of similar studies involving Salmonella Typhi and human-derived macrophages are not consistent. It is important to clarify the functions of the S. Typhi SPI-2 injectisome, not least because an inactivated SPI-2 injectisome forms the basis for live attenuated S. Typhi vaccines that have undergone extensive trials in humans. Intracellular expression of injectisome genes and effector delivery take longer in the S. Typhi/human macrophage model than for S. Typhimurium and we propose that this could explain the conflicting results. Furthermore, strains of both S. Typhimurium and S. Typhi contain intact genes for several 'core' effectors. In S. Typhimurium these cooperate to regulate the vacuole membrane and contribute to intracellular bacterial replication; similar functions are therefore likely in S. Typhi.
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Affiliation(s)
- Teresa L. M. Thurston
- Department of Infectious Disease, Centre for Bacterial Resistance Biology, Imperial College London, London, SW7 2AZ, UK
| | - David W. Holden
- Department of Infectious Disease, Centre for Bacterial Resistance Biology, Imperial College London, London, SW7 2AZ, UK
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8
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Hamblin M, Schade R, Narasimhan R, Monack DM. Salmonella enterica serovar Typhi uses two type 3 secretion systems to replicate in human macrophages and colonize humanized mice. mBio 2023; 14:e0113723. [PMID: 37341487 PMCID: PMC10470537 DOI: 10.1128/mbio.01137-23] [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: 05/03/2023] [Accepted: 05/04/2023] [Indexed: 06/22/2023] Open
Abstract
Salmonella enterica serovar Typhi (S. Typhi) is a human-restricted pathogen that replicates in macrophages. In this study, we investigated the roles of the S. Typhi type 3 secretion systems (T3SSs) encoded on Salmonella pathogenicity islands (SPI)-1 (T3SS-1) and SPI-2 (T3SS-2) during human macrophage infection. We found that mutants of S. Typhi deficient for both T3SSs were defective for intramacrophage replication as measured by flow cytometry, viable bacterial counts, and live time-lapse microscopy. T3SS-secreted proteins PipB2 and SifA contributed to S. Typhi replication and were translocated into the cytosol of human macrophages through both T3SS-1 and T3SS-2, demonstrating functional redundancy for these secretion systems. Importantly, an S. Typhi mutant strain that is deficient for both T3SS-1 and T3SS-2 was severely attenuated in the ability to colonize systemic tissues in a humanized mouse model of typhoid fever. Overall, this study establishes a critical role for S. Typhi T3SSs during its replication within human macrophages and during systemic infection of humanized mice. IMPORTANCE Salmonella enterica serovar Typhi is a human-restricted pathogen that causes typhoid fever. Understanding the key virulence mechanisms that facilitate S. Typhi replication in human phagocytes will enable rational vaccine and antibiotic development to limit the spread of this pathogen. While S. Typhimurium replication in murine models has been studied extensively, there is limited information available about S. Typhi replication in human macrophages, some of which directly conflict with findings from S. Typhimurium murine models. This study establishes that both of S. Typhi's two type 3 secretion systems (T3SS-1 and T3SS-2) contribute to intramacrophage replication and virulence.
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Affiliation(s)
- Meagan Hamblin
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA
| | - Ruth Schade
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA
| | - Ramya Narasimhan
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA
| | - Denise M. Monack
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA
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9
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Chatterjee R, Chowdhury AR, Mukherjee D, Chakravortty D. From Eberthella typhi to Salmonella Typhi: The Fascinating Journey of the Virulence and Pathogenicity of Salmonella Typhi. ACS OMEGA 2023; 8:25674-25697. [PMID: 37521659 PMCID: PMC10373206 DOI: 10.1021/acsomega.3c02386] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/09/2023] [Accepted: 06/30/2023] [Indexed: 08/01/2023]
Abstract
Salmonella Typhi (S. Typhi), the invasive typhoidal serovar of Salmonella enterica that causes typhoid fever in humans, is a severe threat to global health. It is one of the major causes of high morbidity and mortality in developing countries. According to recent WHO estimates, approximately 11-21 million typhoid fever illnesses occur annually worldwide, accounting for 0.12-0.16 million deaths. Salmonella infection can spread to healthy individuals by the consumption of contaminated food and water. Typhoid fever in humans sometimes is accompanied by several other critical extraintestinal complications related to the central nervous system, cardiovascular system, pulmonary system, and hepatobiliary system. Salmonella Pathogenicity Island-1 and Salmonella Pathogenicity Island-2 are the two genomic segments containing genes encoding virulent factors that regulate its invasion and systemic pathogenesis. This Review aims to shed light on a comparative analysis of the virulence and pathogenesis of the typhoidal and nontyphoidal serovars of S. enterica.
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Affiliation(s)
- Ritika Chatterjee
- Department
of Microbiology and Cell Biology, Division of Biological Sciences, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Atish Roy Chowdhury
- Department
of Microbiology and Cell Biology, Division of Biological Sciences, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Debapriya Mukherjee
- Department
of Microbiology and Cell Biology, Division of Biological Sciences, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Dipshikha Chakravortty
- Department
of Microbiology and Cell Biology, Division of Biological Sciences, Indian Institute of Science, Bangalore, Karnataka 560012, India
- Centre
for Biosystems Science and Engineering, Indian Institute of Science, Bangalore, Karnataka 560012, India
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10
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Hamblin M, Schade R, Narasimhan R, Monack DM. Salmonella enterica serovar Typhi uses two type 3 secretion systems to replicate in human macrophages and to colonize humanized mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.06.543980. [PMID: 37333307 PMCID: PMC10274799 DOI: 10.1101/2023.06.06.543980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Salmonella enterica serovar Typhi ( S. Typhi) is a human-restricted pathogen that replicates in macrophages. In this study, we investigated the roles of the S. Typhi Type 3 secretion systems (T3SSs) encoded on Salmonella Pathogenicity Islands (SPI) -1 (T3SS-1) and -2 (T3SS-2) during human macrophage infection. We found that mutants of S . Typhi deficient for both T3SSs were defective for intramacrophage replication as measured by flow cytometry, viable bacterial counts, and live time-lapse microscopy. T3SS-secreted proteins PipB2 and SifA contributed to S. Typhi replication and were translocated into the cytosol of human macrophages through both T3SS-1 and -2, demonstrating functional redundancy for these secretion systems. Importantly, an S . Typhi mutant strain that is deficient for both T3SS-1 and -2 was severely attenuated in the ability to colonize systemic tissues in a humanized mouse model of typhoid fever. Overall, this study establishes a critical role for S. Typhi T3SSs during its replication within human macrophages and during systemic infection of humanized mice. Importance Salmonella enterica serovar Typhi is a human-restricted pathogen that causes typhoid fever. Understanding the key virulence mechanisms that facilitate S. Typhi replication in human phagocytes will enable rational vaccine and antibiotic development to limit spread of this pathogen. While S. Typhimurium replication in murine models has been studied extensively, there is limited information available about S. Typhi replication in human macrophages, some of which directly conflicts with findings from S. Typhimurium murine models. This study establishes that both of S. Typhi's two Type 3 Secretion Systems (T3SS-1 and -2) contribute to intramacrophage replication and virulence.
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11
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Wang BX, Butler DS, Hamblin M, Monack DM. One species, different diseases: the unique molecular mechanisms that underlie the pathogenesis of typhoidal Salmonella infections. Curr Opin Microbiol 2023; 72:102262. [PMID: 36640585 PMCID: PMC10023398 DOI: 10.1016/j.mib.2022.102262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 12/07/2022] [Accepted: 12/16/2022] [Indexed: 01/15/2023]
Abstract
Salmonella enterica is one of the most widespread bacterial pathogens found worldwide, resulting in approximately 100 million infections and over 200 000 deaths per year. Salmonella isolates, termed 'serovars', can largely be classified as either nontyphoidal or typhoidal Salmonella, which differ in regard to disease manifestation and host tropism. Nontyphoidal Salmonella causes gastroenteritis in many hosts, while typhoidal Salmonella is human-restricted and causes typhoid fever, a systemic disease with a mortality rate of up to 30% without treatment. There has been considerable interest in understanding how different Salmonella serovars cause different diseases, but the molecular details that underlie these infections have not yet been fully characterized, especially in the case of typhoidal Salmonella. In this review, we highlight the current state of research into understanding the pathogenesis of both nontyphoidal and typhoidal Salmonella, with a specific interest in serovar-specific traits that allow human-adapted strains of Salmonella to cause enteric fever. Overall, a more detailed molecular understanding of how different Salmonella isolates infect humans will provide critical insights into how we can eradicate these dangerous enteric pathogens.
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Affiliation(s)
- Benjamin X Wang
- Department of Microbiology & Immunology, Stanford University, Stanford, CA, USA
| | - Daniel Sc Butler
- Department of Microbiology & Immunology, Stanford University, Stanford, CA, USA
| | - Meagan Hamblin
- Department of Microbiology & Immunology, Stanford University, Stanford, CA, USA
| | - Denise M Monack
- Department of Microbiology & Immunology, Stanford University, Stanford, CA, USA.
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12
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Carfrae LA, Brown ED. Nutrient stress is a target for new antibiotics. Trends Microbiol 2023; 31:571-585. [PMID: 36709096 DOI: 10.1016/j.tim.2023.01.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 01/05/2023] [Accepted: 01/09/2023] [Indexed: 01/28/2023]
Abstract
Novel approaches are required to address the looming threat of pan-resistant Gram-negative pathogens and forestall the rise of untreatable infections. Unconventional targets that are uniquely important during infection and tractable to high-throughput drug discovery methods hold high potential for innovation in antibiotic discovery programs. In this context, inhibitors of bacterial nutrient stress are particularly exciting candidates for future antibiotic development. Amino acid, nucleotide, and vitamin biosynthesis pathways are critical for bacterial growth in nutrient-limiting conditions in the laboratory and the host. Although historically dismissed as dispensable for pathogens, a wealth of transposon mutagenesis and single-mutant studies have emerged which demonstrate that several such pathways are critical for infection. Indeed, high-throughput screens of diverse synthetic compounds and natural products have uncovered inhibitors of nutrient biosynthesis. Herein, we review bacterial nutrient biosynthesis and its role during host infection. Further, we explore screening platforms developed to search for inhibitors of these targets and highlight successes among these. Finally, we feature important and sometimes surprising connections between bacterial nutrient biosynthesis, antibiotic activity, and antibiotic resistance.
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Affiliation(s)
- Lindsey A Carfrae
- Institute of Infectious Disease Research, McMaster University, Hamilton, Ontario, L8S 4L8, Canada; Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, L8S 4L8, Canada
| | - Eric D Brown
- Institute of Infectious Disease Research, McMaster University, Hamilton, Ontario, L8S 4L8, Canada; Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, L8S 4L8, Canada; Present address: Institute of Infectious Disease Research, McMaster University, Hamilton, Ontario, L8S 4L8, Canada.
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13
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Identification of collaborative cross mouse strains permissive to Salmonella enterica serovar Typhi infection. Sci Rep 2023; 13:393. [PMID: 36624251 PMCID: PMC9829673 DOI: 10.1038/s41598-023-27400-1] [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: 10/01/2022] [Accepted: 01/02/2023] [Indexed: 01/11/2023] Open
Abstract
Salmonella enterica serovar Typhi is the causative agent of typhoid fever restricted to humans and does not replicate in commonly used inbred mice. Genetic variation in humans is far greater and more complex than that in a single inbred strain of mice. The Collaborative Cross (CC) is a large panel of recombinant inbred strains which has a wider range of genetic diversity than laboratory inbred mouse strains. We found that the CC003/Unc and CC053/Unc strains are permissive to intraperitoneal but not oral route of S. Typhi infection and show histopathological changes characteristic of human typhoid. These CC strains are immunocompetent, and immunization induces antigen-specific responses that can kill S. Typhi in vitro and control S. Typhi in vivo. Our results indicate that CC003/Unc and CC053/Unc strains can help identify the genetic basis for typhoid susceptibility, S. Typhi virulence mechanism(s) in vivo, and serve as a preclinical mammalian model system to identify effective vaccines and therapeutics strategies.
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14
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Abstract
Pyroptosis, a regulated form of pro-inflammatory cell death, is characterised by cell lysis and by the release of cytokines, damage- and pathogen-associated molecular patterns. It plays an important role during bacterial infection, where it can promote an inflammatory response and eliminate the replicative niche of intracellular pathogens. Recent work, using a variety of bacterial pathogens, has illuminated the versatility of pyroptosis, revealing unexpected and important concepts underlying host defence. In this Review, we overview the molecular mechanisms underlying pyroptosis and discuss their role in host defence, from the single cell to the whole organism. We focus on recent studies using three cellular microbiology paradigms - Mycobacterium tuberculosis, Salmonella Typhimurium and Shigella flexneri - that have transformed the field of pyroptosis. We compare insights discovered in tissue culture, zebrafish and mouse models, highlighting the advantages and disadvantages of using these complementary infection models to investigate pyroptosis and for modelling human infection. Moving forward, we propose that in-depth knowledge of pyroptosis obtained from complementary infection models can better inform future studies using higher vertebrates, including humans, and help develop innovative host-directed therapies to combat bacterial infection.
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Affiliation(s)
- Dominik Brokatzky
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Serge Mostowy
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
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15
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Maes M, Sikorski MJ, Carey ME, Higginson EE, Dyson ZA, Fernandez A, Araya P, Tennant SM, Baker S, Lagos R, Hormazábal JC, Levine MM, Dougan G. Whole genome sequence analysis of Salmonella Typhi provides evidence of phylogenetic linkage between cases of typhoid fever in Santiago, Chile in the 1980s and 2010-2016. PLoS Negl Trop Dis 2022; 16:e0010178. [PMID: 35767580 PMCID: PMC9275700 DOI: 10.1371/journal.pntd.0010178] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 07/12/2022] [Accepted: 06/08/2022] [Indexed: 11/25/2022] Open
Abstract
Typhoid fever epidemiology was investigated rigorously in Santiago, Chile during the 1980s, when Salmonella enterica serovar Typhi (S. Typhi) caused seasonal, hyperendemic disease. Targeted interventions reduced the annual typhoid incidence rates from 128–220 cases/105 population occurring between 1977–1984 to <8 cases/105 from 1992 onwards. As such, Santiago represents a contemporary example of the epidemiologic transition of an industrialized city from amplified hyperendemic typhoid fever to a period when typhoid is no longer endemic. We used whole genome sequencing (WGS) and phylogenetic analysis to compare the genotypes of S. Typhi cultured from acute cases of typhoid fever occurring in Santiago during the hyperendemic period of the 1980s (n = 74) versus the nonendemic 2010s (n = 80) when typhoid fever was rare. The genotype distribution between “historical” (1980s) isolates and “modern” (2011–2016) isolates was similar, with genotypes 3.5 and 2 comprising the majority of isolations, and 73/80 (91.3%) of modern isolates matching a genotype detected in the 1980s. Additionally, phylogenomically ‘ancient’ genotypes 1.1 and 1.2.1, uncommon in the global collections, were also detected in both eras, with a notable rise amongst the modern isolates. Thus, genotypes of S. Typhi causing acute illness in the modern nonendemic era match the genotypes circulating during the hyperendemic 1980s. The persistence of historical genotypes may be explained by chronic typhoid carriers originally infected during or before the 1980s. Studies of Salmonella Typhi (the cause of typhoid fever) rarely include isolates collected both before and after the interruption of hyperendemic transmission because this typically occurred decades before modern bacteria preservation methods. After substantial reduction in disease, it was assumed that sporadic cases and infrequent outbreaks were due to either chronic biliary carriers or importations, but this was difficult to characterize with low resolution bacterial typing methods. In Santiago, Chile, typhoid fever persisted at hyperendemic levels through the 1980s until organized control efforts in the 1980s and changes to wastewater policy in 1991 caused annual typhoid incidence to plummet. In this study, we used whole genome sequencing (WGS) to investigate whether recent sporadic cases occurring in Santiago in the 2010s were genomically similar to S. Typhi circulating in the 1980s, or dissimilar, possibly representing importations of S. Typhi from outside of Chile. We found concordance amongst S. Typhi genotypes between the 1980s and 2010s, and differences from genotypes circulating in Southeast Asia and Africa where typhoid remains hyperendemic. Our findings suggest that a proportion of modern, rare typhoid cases in Santiago are autochthonous, and that chronic carriers or another unknown reservoir likely contribute. Broadly, our findings corroborate the epidemiologic importance of long-term reservoirs of typhoid fever decades after typhoid elimination.
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Affiliation(s)
- Mailis Maes
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), Department of Medicine, University of Cambridge, Cambridge, United Kingdom
- * E-mail:
| | - Michael J. Sikorski
- Center for Vaccine Development and Global Health (CVD), University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Megan E. Carey
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Ellen E. Higginson
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Zoe A. Dyson
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), Department of Medicine, University of Cambridge, Cambridge, United Kingdom
- Department of Infectious Diseases, Monash University, Melbourne, Australia
- London School of Hygiene & Tropical Medicine, London, United Kingdom
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Alda Fernandez
- Bacteriologia, Subdepartamento de Enfermedades Infecciosas, Departamento de Laboratorio Biomédico, Instituto de Salud Pública de Chile (ISP), Santiago, Chile
| | - Pamela Araya
- Bacteriologia, Subdepartamento de Enfermedades Infecciosas, Departamento de Laboratorio Biomédico, Instituto de Salud Pública de Chile (ISP), Santiago, Chile
| | - Sharon M. Tennant
- Center for Vaccine Development and Global Health (CVD), University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Stephen Baker
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Rosanna Lagos
- Centro para Vacunas en Desarollo-Chile (CVD-Chile), Hospital de Niños Roberto del Rio, Santiago, Chile
| | - Juan Carlos Hormazábal
- Bacteriologia, Subdepartamento de Enfermedades Infecciosas, Departamento de Laboratorio Biomédico, Instituto de Salud Pública de Chile (ISP), Santiago, Chile
| | - Myron M. Levine
- Center for Vaccine Development and Global Health (CVD), University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Gordon Dougan
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), Department of Medicine, University of Cambridge, Cambridge, United Kingdom
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
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16
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Changes in physiological states of Salmonella Typhimurium measured by qPCR with PMA and DyeTox13 Green Azide after pasteurization and UV treatment. Appl Microbiol Biotechnol 2022; 106:2739-2750. [PMID: 35262785 DOI: 10.1007/s00253-022-11850-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 01/17/2022] [Accepted: 02/26/2022] [Indexed: 11/02/2022]
Abstract
Diarrheal diseases caused by Salmonella pose a major threat to public health, and assessment of bacterial viability is critical in determining the safety of food and drinking water after disinfection. Viability PCR could overcome the limitations of traditional culture-dependent methods for a more accurate assessment of the viability of a microbial sample. In this study, the physiological changes in Salmonella Typhimurium induced by pasteurization and UV treatment were evaluated using a culture-based method, RT-qPCR, and viability PCR. The plate count results showed no culturable S. Typhimurium after the pasteurization and UV treatments, while viability PCR with propidium monoazide (PMA) and DyeTox13-qPCR indicated that the membrane integrity of S. Typhimurium remained intact with no metabolic activity. The RT-qPCR results demonstrated that invasion protein (invA) was detectable in UV-treated cells even though the log2-fold change ranged from - 2.13 to - 5.53 for PMA treatment. However, the catalytic activity gene purE was under the detection limit after UV treatment, indicating that most Salmonella entered metabolically inactive status after UV disinfection. Also, viability PCRs were tested with artificially contaminated eggs to determine physiological status on actual food matrices. DyeTox13-qPCR methods showed that most Salmonella lost their metabolic activity but retained membrane integrity after UV disinfection. RT-qPCR may not determine the physiological status of Salmonella after UV disinfection because mRNA could be detectable in UV-treated cells depending on the choice of target gene. Viability PCR demonstrated potential for rapid and specific detection of pathogens with physiological states such as membrane integrity and metabolic activity.Key Points• Membrane integrity of Salmonella remained intact with no metabolic activity after UV.• mRNA could be detectable in UV-treated cells depending on the choice of target gene.• Viability PCR could rapidly detect specific pathogens with their physiological states.
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17
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Stepien TA, Libby SJ, Karlinsey JE, Brehm MA, Greiner DL, Shultz LD, Brabb T, Fang FC. Analysis of Salmonella Typhi Pathogenesis in a Humanized Mouse Model. Methods Mol Biol 2022; 2427:215-234. [PMID: 35619037 PMCID: PMC9682973 DOI: 10.1007/978-1-0716-1971-1_18] [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: 01/03/2023]
Abstract
Efforts to understand molecular mechanisms of pathogenesis of the human-restricted pathogen Salmonella enterica serovar Typhi, the causative agent of typhoid fever, have been hampered by the lack of a tractable small animal model. This obstacle has been surmounted by a humanized mouse model in which genetically modified mice are engrafted with purified CD34+ stem cells from human umbilical cord blood, designated CD34+ Hu-NSG (formerly hu-SRC-SCID) mice. We have shown that these mice develop a lethal systemic infection with S. Typhi that is dependent on the presence of engrafted human hematopoietic cells. Immunological and pathological features of human typhoid are recapitulated in this model, which has been successfully employed for the identification of bacterial genetic determinants of S. Typhi virulence. Here we describe the methods used to infect CD34+ Hu-NSG mice with S. Typhi in humanized mice and to construct and analyze a transposon-directed insertion site sequencing S. Typhi library, and provide general considerations for the use of humanized mice for the study of a human-restricted pathogen.
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Affiliation(s)
- Taylor A Stepien
- Department of Global Health, University of Washington, Seattle, WA, USA
| | - Stephen J Libby
- Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA, USA
| | - Joyce E Karlinsey
- Department of Microbiology, University of Washington, Seattle, WA, USA
| | - Michael A Brehm
- Department of Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, USA
| | - Dale L Greiner
- Department of Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, USA
| | | | - Thea Brabb
- Department of Comparative Medicine, University of Washington, Seattle, WA, USA
| | - Ferric C Fang
- Department of Global Health, University of Washington, Seattle, WA, USA.,Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA, USA.,Department of Microbiology, University of Washington, Seattle, WA, USA
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18
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Hullahalli K, Waldor MK. Pathogen clonal expansion underlies multiorgan dissemination and organ-specific outcomes during murine systemic infection. eLife 2021; 10:e70910. [PMID: 34636322 PMCID: PMC8545400 DOI: 10.7554/elife.70910] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 10/07/2021] [Indexed: 12/31/2022] Open
Abstract
The dissemination of pathogens through blood and their establishment within organs lead to severe clinical outcomes. However, the within-host dynamics that underlie pathogen spread to and clearance from systemic organs remain largely uncharacterized. In animal models of infection, the observed pathogen population results from the combined contributions of bacterial replication, persistence, death, and dissemination, each of which can vary across organs. Quantifying the contribution of each these processes is required to interpret and understand experimental phenotypes. Here, we leveraged STAMPR, a new barcoding framework, to investigate the population dynamics of extraintestinal pathogenic Escherichia coli, a common cause of bacteremia, during murine systemic infection. We show that while bacteria are largely cleared by most organs, organ-specific clearance failures are pervasive and result from dramatic expansions of clones representing less than 0.0001% of the inoculum. Clonal expansion underlies the variability in bacterial burden between animals, and stochastic dissemination of clones profoundly alters the pathogen population structure within organs. Despite variable pathogen expansion events, host bottlenecks are consistent yet highly sensitive to infection variables, including inoculum size and macrophage depletion. We adapted our barcoding methodology to facilitate multiplexed validation of bacterial fitness determinants identified with transposon mutagenesis and confirmed the importance of bacterial hexose metabolism and cell envelope homeostasis pathways for organ-specific pathogen survival. Collectively, our findings provide a comprehensive map of the population biology that underlies bacterial systemic infection and a framework for barcode-based high-resolution mapping of infection dynamics.
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Affiliation(s)
- Karthik Hullahalli
- Department of Microbiology, Harvard Medical SchoolBostonUnited States
- Division of Infectious Diseases, Brigham & Women’s HospitalBostonUnited States
| | - Matthew K Waldor
- Department of Microbiology, Harvard Medical SchoolBostonUnited States
- Division of Infectious Diseases, Brigham & Women’s HospitalBostonUnited States
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19
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Wang J, Ma S, Li W, Wang X, Huang D, Jiang L, Feng L. Salmonella enterica Serovar Typhi Induces Host Metabolic Reprogramming to Increase Glucose Availability for Intracellular Replication. Int J Mol Sci 2021; 22:ijms221810003. [PMID: 34576166 PMCID: PMC8467381 DOI: 10.3390/ijms221810003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 09/13/2021] [Accepted: 09/14/2021] [Indexed: 11/18/2022] Open
Abstract
Salmonella enterica serovar Typhi (S. Typhi) is a human-limited intracellular pathogen and the cause of typhoid fever, a severe systemic disease. Pathogen–host interaction at the metabolic level affects the pathogenicity of intracellular pathogens, but it remains unclear how S. Typhi infection influences host metabolism for its own benefit. Herein, using metabolomics and transcriptomics analyses, combined with in vitro and in vivo infection assays, we investigated metabolic responses in human macrophages during S. Typhi infection, and the impact of these responses on S. Typhi intracellular replication and systemic pathogenicity. We observed increased glucose content, higher rates of glucose uptake and glycolysis, and decreased oxidative phosphorylation in S. Typhi-infected human primary macrophages. Replication in human macrophages and the bacterial burden in systemic organs of humanized mice were reduced by either the inhibition of host glucose uptake or a mutation of the bacterial glucose uptake system, indicating that S. Typhi utilizes host-derived glucose to enhance intracellular replication and virulence. Thus, S. Typhi promotes its pathogenicity by inducing metabolic changes in host macrophages and utilizing the glucose that subsequently accumulates as a nutrient for intracellular replication. Our findings provide the first metabolic signature of S. Typhi-infected host cells and identifies a new strategy utilized by S. Typhi for intracellular replication.
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Affiliation(s)
- Jingting Wang
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin 300457, China; (J.W.); (S.M.); (W.L.); (X.W.); (D.H.)
- Tianjin Key Laboratory of Microbial Functional Genomics, TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin 300457, China
| | - Shuai Ma
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin 300457, China; (J.W.); (S.M.); (W.L.); (X.W.); (D.H.)
- Tianjin Key Laboratory of Microbial Functional Genomics, TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin 300457, China
| | - Wanwu Li
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin 300457, China; (J.W.); (S.M.); (W.L.); (X.W.); (D.H.)
- Tianjin Key Laboratory of Microbial Functional Genomics, TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin 300457, China
| | - Xinyue Wang
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin 300457, China; (J.W.); (S.M.); (W.L.); (X.W.); (D.H.)
- Tianjin Key Laboratory of Microbial Functional Genomics, TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin 300457, China
| | - Di Huang
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin 300457, China; (J.W.); (S.M.); (W.L.); (X.W.); (D.H.)
- Tianjin Key Laboratory of Microbial Functional Genomics, TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin 300457, China
| | - Lingyan Jiang
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin 300457, China; (J.W.); (S.M.); (W.L.); (X.W.); (D.H.)
- Tianjin Key Laboratory of Microbial Functional Genomics, TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin 300457, China
- Correspondence: (L.J.); (L.F.)
| | - Lu Feng
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin 300457, China; (J.W.); (S.M.); (W.L.); (X.W.); (D.H.)
- Tianjin Key Laboratory of Microbial Functional Genomics, TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin 300457, China
- Correspondence: (L.J.); (L.F.)
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20
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Cappable-Seq Reveals Specific Patterns of Metabolism and Virulence for Salmonella Typhimurium Intracellular Survival within Acanthamoeba castellanii. Int J Mol Sci 2021; 22:ijms22169077. [PMID: 34445780 PMCID: PMC8396566 DOI: 10.3390/ijms22169077] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 08/16/2021] [Accepted: 08/19/2021] [Indexed: 01/21/2023] Open
Abstract
The bacterial pathogen Salmonella enterica, which causes enteritis, has a broad host range and extensive environmental longevity. In water and soil, Salmonella interacts with protozoa and multiplies inside their phagosomes. Although this relationship resembles that between Salmonella and mammalian phagocytes, the interaction mechanisms and bacterial genes involved are unclear. Here, we characterized global gene expression patterns of S. enterica serovar Typhimurium within Acanthamoeba castellanii at the early stage of infection by Cappable-Seq. Gene expression features of S. Typhimurium within A. castellanii were presented with downregulation of glycolysis-related, and upregulation of glyoxylate cycle-related genes. Expression of Salmonella Pathogenicity Island-1 (SPI-1), chemotaxis system, and flagellar apparatus genes was upregulated. Furthermore, expression of genes mediating oxidative stress response and iron uptake was upregulated within A. castellanii as well as within mammalian phagocytes. Hence, global S. Typhimurium gene expression patterns within A. castellanii help better understand the molecular mechanisms of Salmonella adaptation to an amoeba cell and intracellular persistence in protozoa inhabiting water and soil ecosystems.
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21
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Groisman EA, Duprey A, Choi J. How the PhoP/PhoQ System Controls Virulence and Mg 2+ Homeostasis: Lessons in Signal Transduction, Pathogenesis, Physiology, and Evolution. Microbiol Mol Biol Rev 2021; 85:e0017620. [PMID: 34191587 PMCID: PMC8483708 DOI: 10.1128/mmbr.00176-20] [Citation(s) in RCA: 59] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The PhoP/PhoQ two-component system governs virulence, Mg2+ homeostasis, and resistance to a variety of antimicrobial agents, including acidic pH and cationic antimicrobial peptides, in several Gram-negative bacterial species. Best understood in Salmonella enterica serovar Typhimurium, the PhoP/PhoQ system consists o-regulated gene products alter PhoP-P amounts, even under constant inducing conditions. PhoP-P controls the abundance of hundreds of proteins both directly, by having transcriptional effects on the corresponding genes, and indirectly, by modifying the abundance, activity, or stability of other transcription factors, regulatory RNAs, protease regulators, and metabolites. The investigation of PhoP/PhoQ has uncovered novel forms of signal transduction and the physiological consequences of regulon evolution.
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Affiliation(s)
- Eduardo A. Groisman
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut, USA
- Yale Microbial Sciences Institute, West Haven, Connecticut, USA
| | - Alexandre Duprey
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut, USA
| | - Jeongjoon Choi
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut, USA
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22
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Schultz BM, Melo-Gonzalez F, Salazar GA, Porto BN, Riedel CA, Kalergis AM, Bueno SM. New Insights on the Early Interaction Between Typhoid and Non-typhoid Salmonella Serovars and the Host Cells. Front Microbiol 2021; 12:647044. [PMID: 34276584 PMCID: PMC8282409 DOI: 10.3389/fmicb.2021.647044] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 06/08/2021] [Indexed: 11/13/2022] Open
Abstract
Salmonella enterica is a common source of food and water-borne infections, causing a wide range of clinical ailments in both human and animal hosts. Immunity to Salmonella involves an interplay between different immune responses, which are rapidly initiated to control bacterial burden. However, Salmonella has developed several strategies to evade and modulate the host immune responses. In this sense, the main knowledge about the pathogenicity of this bacterium has been obtained by the study of mouse models with non-typhoidal serovars. However, this knowledge is not representative of all the pathologies caused by non-typhoidal serovars in the human. Here we review the most important features of typhoidal and non-typhoidal serovars and the diseases they cause in the human host, describing the virulence mechanisms used by these pathogens that have been identified in different models of infection.
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Affiliation(s)
- Bárbara M Schultz
- Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Felipe Melo-Gonzalez
- Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Geraldyne A Salazar
- Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Bárbara N Porto
- Laboratory of Clinical and Experimental Immunology, School of Medicine, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, Brazil.,Program in Translational Medicine, Hospital for Sick Children, Toronto, ON, Canada
| | - Claudia A Riedel
- Departamento de Ciencias Biológicas, Facultad de Ciencias de la Vida, Millennium Institute on Immunology and Immunotherapy, Universidad Andrés Bello, Santiago, Chile
| | - Alexis M Kalergis
- Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile.,Departamento de Endocrinología, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Susan M Bueno
- Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
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23
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Reuter T, Scharte F, Franzkoch R, Liss V, Hensel M. Single cell analyses reveal distinct adaptation of typhoidal and non-typhoidal Salmonella enterica serovars to intracellular lifestyle. PLoS Pathog 2021; 17:e1009319. [PMID: 34143852 PMCID: PMC8244875 DOI: 10.1371/journal.ppat.1009319] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 06/30/2021] [Accepted: 05/14/2021] [Indexed: 01/06/2023] Open
Abstract
Salmonella enterica is a common foodborne, facultative intracellular enteropathogen. Human-restricted typhoidal S. enterica serovars Typhi (STY) or Paratyphi A (SPA) cause severe typhoid or paratyphoid fever, while many S. enterica serovar Typhimurium (STM) strains have a broad host range and in human hosts usually lead to a self-limiting gastroenteritis. Due to restriction of STY and SPA to primate hosts, experimental systems for studying the pathogenesis of typhoid and paratyphoid fever are limited. Therefore, STM infection of susceptible mice is commonly considered as model system for studying these diseases. The type III secretion system encoded by Salmonella pathogenicity island 2 (SPI2-T3SS) is a key factor for intracellular survival of Salmonella. Inside host cells, the pathogen resides within the Salmonella-containing vacuole (SCV) and induces tubular structures extending from the SCV, termed Salmonella-induced filaments (SIF). This study applies single cell analyses approaches, which are flow cytometry of Salmonella harboring dual fluorescent protein reporters, effector translocation, and correlative light and electron microscopy to investigate the fate and activities of intracellular STY and SPA. The SPI2-T3SS of STY and SPA is functional in translocation of effector proteins, SCV and SIF formation. However, only a low proportion of intracellular STY and SPA are actively deploying SPI2-T3SS and STY and SPA exhibited a rapid decline of protein biosynthesis upon experimental induction. A role of SPI2-T3SS for proliferation of STY and SPA in epithelial cells was observed, but not for survival or proliferation in phagocytic host cells. Our results indicate that reduced intracellular activities are factors of the stealth strategy of STY and SPA and facilitate systemic spread and persistence of the typhoidal Salmonella. Typhoidal Salmonella enterica serovars Typhi (STY) and Paratyphi A (SPA) cause a major disease burden to the human population. The restriction of these pathogens to human hosts limits experimental analyses of molecular mechanisms of diseases. S. enterica serovar Typhimurium is commonly used as surrogate model for typhoidal Salmonella (TS), and allowed the identification of virulence factors for intracellular lifestyle of S. enterica in mammalian host cells. If virulence factors, such as the Salmonella Pathogenicity Island 2-encoded type III secretion system (SPI2-T3SS) have similar roles for intracellular lifestyle of TS is largely unknown. We analyzed, on single cell level, the intracellular activities of STY and SPA in comparison to STM. STY and SPA deploy SPI2-T3SS to actively manipulate their host cells, but with far lower frequency than STM. Our work supports a model of TS as stealth pathogens that persist in host cells.
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Affiliation(s)
- Tatjana Reuter
- Abt. Mikrobiologie, Universität Osnabrück, Osnabrück, Germany
| | - Felix Scharte
- Abt. Mikrobiologie, Universität Osnabrück, Osnabrück, Germany
| | - Rico Franzkoch
- Abt. Mikrobiologie, Universität Osnabrück, Osnabrück, Germany
- iBiOs–integrated Bioimaging Facility Osnabrück, Universität Osnabrück, Osnabrück, Germany
| | - Viktoria Liss
- Abt. Mikrobiologie, Universität Osnabrück, Osnabrück, Germany
- iBiOs–integrated Bioimaging Facility Osnabrück, Universität Osnabrück, Osnabrück, Germany
| | - Michael Hensel
- Abt. Mikrobiologie, Universität Osnabrück, Osnabrück, Germany
- CellNanOs–Center of Cellular Nanoanalytics Osnabrück, Universität Osnabrück, Osnabrück, Germany
- * E-mail:
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24
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Klebba PE, Newton SMC, Six DA, Kumar A, Yang T, Nairn BL, Munger C, Chakravorty S. Iron Acquisition Systems of Gram-negative Bacterial Pathogens Define TonB-Dependent Pathways to Novel Antibiotics. Chem Rev 2021; 121:5193-5239. [PMID: 33724814 PMCID: PMC8687107 DOI: 10.1021/acs.chemrev.0c01005] [Citation(s) in RCA: 58] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Iron is an indispensable metabolic cofactor in both pro- and eukaryotes, which engenders a natural competition for the metal between bacterial pathogens and their human or animal hosts. Bacteria secrete siderophores that extract Fe3+ from tissues, fluids, cells, and proteins; the ligand gated porins of the Gram-negative bacterial outer membrane actively acquire the resulting ferric siderophores, as well as other iron-containing molecules like heme. Conversely, eukaryotic hosts combat bacterial iron scavenging by sequestering Fe3+ in binding proteins and ferritin. The variety of iron uptake systems in Gram-negative bacterial pathogens illustrates a range of chemical and biochemical mechanisms that facilitate microbial pathogenesis. This document attempts to summarize and understand these processes, to guide discovery of immunological or chemical interventions that may thwart infectious disease.
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Affiliation(s)
- Phillip E Klebba
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, Kansas 66506, United States
| | - Salete M C Newton
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, Kansas 66506, United States
| | - David A Six
- Venatorx Pharmaceuticals, Inc., 30 Spring Mill Drive, Malvern, Pennsylvania 19355, United States
| | - Ashish Kumar
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, Kansas 66506, United States
| | - Taihao Yang
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, Kansas 66506, United States
| | - Brittany L Nairn
- Department of Biological Sciences, Bethel University, 3900 Bethel Drive, St. Paul, Minnesota 55112, United States
| | - Colton Munger
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, Kansas 66506, United States
| | - Somnath Chakravorty
- Jacobs School of Medicine and Biomedical Sciences, SUNY Buffalo, Buffalo, New York 14203, United States
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25
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Bouvenot T, Dewitte A, Bennaceur N, Pradel E, Pierre F, Bontemps-Gallo S, Sebbane F. Interplay between Yersinia pestis and its flea vector in lipoate metabolism. THE ISME JOURNAL 2021; 15:1136-1149. [PMID: 33479491 PMCID: PMC8182812 DOI: 10.1038/s41396-020-00839-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 10/22/2020] [Accepted: 11/11/2020] [Indexed: 01/29/2023]
Abstract
To thrive, vector-borne pathogens must survive in the vector's gut. How these pathogens successfully exploit this environment in time and space has not been extensively characterized. Using Yersinia pestis (the plague bacillus) and its flea vector, we developed a bioluminescence-based approach and employed it to investigate the mechanisms of pathogenesis at an unprecedented level of detail. Remarkably, lipoylation of metabolic enzymes, via the biosynthesis and salvage of lipoate, increases the Y. pestis transmission rate by fleas. Interestingly, the salvage pathway's lipoate/octanoate ligase LplA enhances the first step in lipoate biosynthesis during foregut colonization but not during midgut colonization. Lastly, Y. pestis primarily uses lipoate provided by digestive proteolysis (presumably as lipoyl peptides) rather than free lipoate in blood, which is quickly depleted by the vector. Thus, spatial and temporal factors dictate the bacterium's lipoylation strategies during an infection, and replenishment of lipoate by digestive proteolysis in the vector might constitute an Achilles' heel that is exploited by pathogens.
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Affiliation(s)
- Typhanie Bouvenot
- grid.503422.20000 0001 2242 6780Univ. Lille, Inserm, CNRS, CHU Lille, Institut Pasteur de Lille, U1019 - UMR 9017 – CIIL - Center for Infection and Immunity of Lille, F-59000 Lille, France
| | - Amélie Dewitte
- grid.503422.20000 0001 2242 6780Univ. Lille, Inserm, CNRS, CHU Lille, Institut Pasteur de Lille, U1019 - UMR 9017 – CIIL - Center for Infection and Immunity of Lille, F-59000 Lille, France
| | - Nadia Bennaceur
- grid.503422.20000 0001 2242 6780Univ. Lille, Inserm, CNRS, CHU Lille, Institut Pasteur de Lille, U1019 - UMR 9017 – CIIL - Center for Infection and Immunity of Lille, F-59000 Lille, France
| | - Elizabeth Pradel
- grid.503422.20000 0001 2242 6780Univ. Lille, Inserm, CNRS, CHU Lille, Institut Pasteur de Lille, U1019 - UMR 9017 – CIIL - Center for Infection and Immunity of Lille, F-59000 Lille, France
| | - François Pierre
- grid.503422.20000 0001 2242 6780Univ. Lille, Inserm, CNRS, CHU Lille, Institut Pasteur de Lille, U1019 - UMR 9017 – CIIL - Center for Infection and Immunity of Lille, F-59000 Lille, France
| | - Sébastien Bontemps-Gallo
- grid.503422.20000 0001 2242 6780Univ. Lille, Inserm, CNRS, CHU Lille, Institut Pasteur de Lille, U1019 - UMR 9017 – CIIL - Center for Infection and Immunity of Lille, F-59000 Lille, France
| | - Florent Sebbane
- grid.503422.20000 0001 2242 6780Univ. Lille, Inserm, CNRS, CHU Lille, Institut Pasteur de Lille, U1019 - UMR 9017 – CIIL - Center for Infection and Immunity of Lille, F-59000 Lille, France
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26
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Sousa Gerós A, Simmons A, Drakesmith H, Aulicino A, Frost JN. The battle for iron in enteric infections. Immunology 2020; 161:186-199. [PMID: 32639029 PMCID: PMC7576875 DOI: 10.1111/imm.13236] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 07/01/2020] [Indexed: 02/06/2023] Open
Abstract
Iron is an essential element for almost all living organisms, but can be extremely toxic in high concentrations. All organisms must therefore employ homeostatic mechanisms to finely regulate iron uptake, usage and storage in the face of dynamic environmental conditions. The critical step in mammalian systemic iron homeostasis is the fine regulation of dietary iron absorption. However, as the gastrointestinal system is also home to >1014 bacteria, all of which engage in their own programmes of iron homeostasis, the gut represents an anatomical location where the inter-kingdom fight for iron is never-ending. Here, we explore the molecular mechanisms of, and interactions between, host and bacterial iron homeostasis in the gastrointestinal tract. We first detail how mammalian systemic and cellular iron homeostasis influences gastrointestinal iron availability. We then focus on two important human pathogens, Salmonella and Clostridia; despite their differences, they exemplify how a bacterial pathogen must navigate and exploit this web of iron homeostasis interactions to avoid host nutritional immunity and replicate successfully. We then reciprocally explore how iron availability interacts with the gastrointestinal microbiota, and the consequences of this on mammalian physiology and pathogen iron acquisition. Finally, we address how understanding the battle for iron in the gastrointestinal tract might inform clinical practice and inspire new treatments for important diseases.
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Affiliation(s)
- Ana Sousa Gerós
- MRC Human Immunology UnitWeatherall Institute of Molecular MedicineUniversity of OxfordOxfordUK
- Translational Gastroenterology UnitJohn Radcliffe HospitalOxfordUK
| | - Alison Simmons
- MRC Human Immunology UnitWeatherall Institute of Molecular MedicineUniversity of OxfordOxfordUK
- Translational Gastroenterology UnitJohn Radcliffe HospitalOxfordUK
| | - Hal Drakesmith
- MRC Human Immunology UnitWeatherall Institute of Molecular MedicineUniversity of OxfordOxfordUK
| | - Anna Aulicino
- MRC Human Immunology UnitWeatherall Institute of Molecular MedicineUniversity of OxfordOxfordUK
- Translational Gastroenterology UnitJohn Radcliffe HospitalOxfordUK
| | - Joe N. Frost
- MRC Human Immunology UnitWeatherall Institute of Molecular MedicineUniversity of OxfordOxfordUK
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27
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Wang H, Zeng X, Lin J. Enterobactin-specific antibodies inhibit in vitro growth of different gram-negative bacterial pathogens. Vaccine 2020; 38:7764-7773. [PMID: 33164800 DOI: 10.1016/j.vaccine.2020.10.040] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 09/26/2020] [Accepted: 10/12/2020] [Indexed: 01/17/2023]
Abstract
Enterobactin (Ent)-mediated high affinity iron acquisition is critically important for Gram-negative bacterial pathogens to survive and infect the host. Recently, we reported an efficient method to prepare novel Ent conjugate vaccines for inducing high level of Ent-specific antibodies, which displayed similar bacteriostatic feature as lipocalins, the host innate immune effectors with potent Ent-binding ability. The Ent-specific antibodies also showed a significant advantage over lipocalins by cross-reacting to various Ent derivatives including salmochelins, the glycosylated Ent that can help enteric pathogens evade the siderophore sequestration by host lipocalins. To demonstrate significant potential of the Ent conjugate vaccine for broader applications to prevent and control various Gram-negative infections in human and animal, in this study, we examined inhibitory effect of Ent-specific antibodies on the in vitro growth of three significant Gram-negative pathogens: Escherichia coli (n = 27), Salmonella enterica (n = 8), and Campylobacter spp. (n = 6). The tested strains were diverse with respect to hosts, geographical origins, serotypes, infection sites and siderophore productions. The Ent-specific antibodies significantly suppressed the growth of each tested strain under iron-restricted conditions. For example, the Ent-specific antibodies consistently exerted 2-5 log10 units of growth reduction on most tested avian pathogenic E. coli (9 of 10 strains) isolated in five countries. Despite various dynamic growth responses observed, notably, the Ent-specific antibodies displayed significantly higher magnitude of growth reduction than lipocalin-2 (up to 5 log10 units of difference) on majority of tested E. coli and S. enterica, which is likely due to sequestration of other siderophores (e.g., salmochelins) by the Ent-specific antibodies. Production of a variety of major siderophores by the tested E. coli and S. enterica strains was examined and confirmed by ultra high performance liquid chromatography-high resolution mass spectrometry analysis. Collectively, this study provides critical and compelling in vitro evidence supporting the feasibility of Ent-based immune interventions against several Gram-negative pathogens.
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Affiliation(s)
- Huiwen Wang
- Department of Animal Science, The University of Tennessee, Knoxville, TN, USA
| | - Ximin Zeng
- Department of Animal Science, The University of Tennessee, Knoxville, TN, USA
| | - Jun Lin
- Department of Animal Science, The University of Tennessee, Knoxville, TN, USA.
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28
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Abstract
Trehalose is a disaccharide of two D-glucose molecules linked by a glycosidic linkage, which plays both structural and functional roles in bacteria. Trehalose can be synthesized and degraded by several pathways, and induction of trehalose biosynthesis is typically associated with exposure to abiotic stress. The ability of trehalose to protect against abiotic stress has been exploited to stabilize a range of bacterial vaccines. More recently, there has been interest in the role of this molecule in microbial virulence. There is now evidence that trehalose or trehalose derivatives play important roles in virulence of a diverse range of Gram-positive and Gram-negative pathogens of animals or plants. Trehalose and/or trehalose derivatives can play important roles in host colonization and growth in the host, and can modulate the interactions with host defense mechanisms. However, the roles are typically pathogen-specific. These findings suggest that trehalose metabolism may be a target for novel pathogen-specific rather than broad spectrum interventions.
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Affiliation(s)
- Muthita Vanaporn
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University , Bangkok, Thailand
| | - Richard W Titball
- College of Life and Environmental Sciences, University of Exeter , Exeter, UK
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29
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Weber BS, De Jong AM, Guo AB, Dharavath S, French S, Fiebig-Comyn AA, Coombes BK, Magolan J, Brown ED. Genetic and Chemical Screening in Human Blood Serum Reveals Unique Antibacterial Targets and Compounds against Klebsiella pneumoniae. Cell Rep 2020; 32:107927. [DOI: 10.1016/j.celrep.2020.107927] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 04/30/2020] [Accepted: 06/26/2020] [Indexed: 12/15/2022] Open
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30
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Murret-Labarthe C, Kerhoas M, Dufresne K, Daigle F. New Roles for Two-Component System Response Regulators of Salmonella enterica Serovar Typhi during Host Cell Interactions. Microorganisms 2020; 8:microorganisms8050722. [PMID: 32413972 PMCID: PMC7285189 DOI: 10.3390/microorganisms8050722] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 05/04/2020] [Accepted: 05/09/2020] [Indexed: 12/12/2022] Open
Abstract
In order to survive external stresses, bacteria need to adapt quickly to changes in their environment. One adaptive mechanism is to coordinate and alter their gene expression by using two-component systems (TCS). TCS are composed of a sensor kinase that activates a transcriptional response regulator by phosphorylation. TCS are involved in motility, virulence, nutrient acquisition, and envelope stress in many bacteria. The pathogenic bacteria Salmonella enterica serovar Typhi (S. Typhi) possess 30 TCSs, is specific to humans, and causes typhoid fever. Here, we have individually deleted each of the 30 response regulators. We have determined their role during interaction with host cells (epithelial cells and macrophages). Deletion of most of the systems (24 out of 30) resulted in a significant change during infection. We have identified 32 new phenotypes associated with TCS of S. Typhi. Some previously known phenotypes associated with TCSs in Salmonella were also confirmed. We have also uncovered phenotypic divergence between Salmonella serovars, as distinct phenotypes between S. Typhi and S. Typhimurium were identified for cpxR. This finding highlights the importance of specifically studying S. Typhi to understand its pathogenesis mechanisms and to develop strategies to potentially reduce typhoid infections.
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31
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Selection or drift: The population biology underlying transposon insertion sequencing experiments. Comput Struct Biotechnol J 2020; 18:791-804. [PMID: 32280434 PMCID: PMC7138912 DOI: 10.1016/j.csbj.2020.03.021] [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: 10/15/2019] [Revised: 03/06/2020] [Accepted: 03/22/2020] [Indexed: 01/23/2023] Open
Abstract
Transposon insertion sequencing methods such as Tn-seq revolutionized microbiology by allowing the identification of genomic loci that are critical for viability in a specific environment on a genome-wide scale. While powerful, transposon insertion sequencing suffers from limited reproducibility when different analysis methods are compared. From the perspective of population biology, this may be explained by changes in mutant frequency due to chance (drift) rather than differential fitness (selection). Here, we develop a mathematical model of the population biology of transposon insertion sequencing experiments, i.e. the changes in size and composition of the transposon-mutagenized population during the experiment. We use this model to investigate mutagenesis, the growth of the mutant library, and its passage through bottlenecks. Specifically, we study how these processes can lead to extinction of individual mutants depending on their fitness and the distribution of fitness effects (DFE) of the entire mutant population. We find that in typical in vitro experiments few mutants with high fitness go extinct. However, bottlenecks of a size that is common in animal infection models lead to so much random extinction that a large number of viable mutants would be misclassified. While mutants with low fitness are more likely to be lost during the experiment, mutants with intermediate fitness are expected to be much more abundant and can constitute a large proportion of detected hits, i.e. false positives. Thus, incorporating the DFEs of randomly generated mutations in the analysis may improve the reproducibility of transposon insertion experiments, especially when strong bottlenecks are encountered.
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32
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Zhu W, Winter MG, Spiga L, Hughes ER, Chanin R, Mulgaonkar A, Pennington J, Maas M, Behrendt CL, Kim J, Sun X, Beiting DP, Hooper LV, Winter SE. Xenosiderophore Utilization Promotes Bacteroides thetaiotaomicron Resilience during Colitis. Cell Host Microbe 2020; 27:376-388.e8. [PMID: 32075741 DOI: 10.1016/j.chom.2020.01.010] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 12/02/2019] [Accepted: 01/16/2020] [Indexed: 02/06/2023]
Abstract
During short-lived perturbations, such as inflammation, the gut microbiota exhibits resilience and reverts to its original configuration. Although microbial access to the micronutrient iron is decreased during colitis, pathogens can scavenge iron by using siderophores. How commensal bacteria acquire iron during gut inflammation is incompletely understood. Curiously, the human commensal Bacteroides thetaiotaomicron does not produce siderophores but grows under iron-limiting conditions using enterobacterial siderophores. Using RNA-seq, we identify B. thetaiotaomicron genes that were upregulated during Salmonella-induced gut inflammation and were predicted to be involved in iron uptake. Mutants in the xusABC locus (BT2063-2065) were defective for xenosiderophore-mediated iron uptake in vitro. In the normal mouse gut, the XusABC system was dispensable, while a xusA mutant colonized poorly during colitis. This work identifies xenosiderophore utilization as a critical mechanism for B. thetaiotaomicron to sustain colonization during inflammation and suggests a mechanism of how interphylum iron metabolism contributes to gut microbiota resilience.
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Affiliation(s)
- Wenhan Zhu
- Department of Microbiology, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Maria G Winter
- Department of Microbiology, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Luisella Spiga
- Department of Microbiology, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Elizabeth R Hughes
- Department of Microbiology, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Rachael Chanin
- Department of Microbiology, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Aditi Mulgaonkar
- Radiology and Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jenelle Pennington
- Radiology and Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Michelle Maas
- Department of Microbiology, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Cassie L Behrendt
- Department of Immunology, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jiwoong Kim
- Department of Population and Data Sciences, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Xiankai Sun
- Radiology and Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Daniel P Beiting
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Lora V Hooper
- Department of Immunology, UT Southwestern Medical Center, Dallas, TX 75390, USA; Howard Hughes Medical Institute, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Sebastian E Winter
- Department of Microbiology, UT Southwestern Medical Center, Dallas, TX 75390, USA.
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Salmonella enterica Serovar Typhimurium Uses PbgA/YejM To Regulate Lipopolysaccharide Assembly during Bacteremia. Infect Immun 2019; 88:IAI.00758-19. [PMID: 31611279 PMCID: PMC6921655 DOI: 10.1128/iai.00758-19] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 10/01/2019] [Indexed: 12/14/2022] Open
Abstract
Salmonella enterica serovar Typhimurium (S Typhimurium) relies upon the inner membrane protein PbgA to enhance outer membrane (OM) integrity and promote virulence in mice. The PbgA transmembrane domain (residues 1 to 190) is essential for viability, while the periplasmic domain (residues 191 to 586) is dispensable. Residues within the basic region (residues 191 to 245) bind acidic phosphates on polar phospholipids, like for cardiolipins, and are necessary for salmonella OM integrity. S Typhimurium bacteria increase their OM cardiolipin concentrations during activation of the PhoPQ regulators. The mechanism involves PbgA's periplasmic globular region (residues 245 to 586), but the biological role of increasing cardiolipins on the surface is not understood. Nonsynonymous polymorphisms in three essential lipopolysaccharide (LPS) synthesis regulators, lapB (also known as yciM), ftsH, and lpxC, variably suppressed the defects in OM integrity, rifampin resistance, survival in macrophages, and systemic colonization of mice in the pbgAΔ191-586 mutant (in which the PbgA periplasmic domain from residues 191 to 586 is deleted). Compared to the OMs of the wild-type salmonellae, the OMs of the pbgA mutants had increased levels of lipid A-core molecules, cardiolipins, and phosphatidylethanolamines and decreased levels of specific phospholipids with cyclopropanated fatty acids. Complementation and substitution mutations in LapB and LpxC generally restored the phospholipid and LPS assembly defects for the pbgA mutants. During bacteremia, mice infected with the pbgA mutants survived and cleared the bacteria, while animals infected with wild-type salmonellae succumbed within 1 week. Remarkably, wild-type mice survived asymptomatically with pbgA-lpxC salmonellae in their livers and spleens for months, but Toll-like receptor 4-deficient animals succumbed to these infections within roughly 1 week. In summary, S Typhimurium uses PbgA to influence LPS assembly during stress in order to survive, adapt, and proliferate within the host environment.
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34
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Wang N, Knodler LA, Strugnell RA. Typhoid Fever: The More We Learn, the Less We Know (Apologies, Albert Einstein). Cell Host Microbe 2019; 26:303-306. [PMID: 31513767 DOI: 10.1016/j.chom.2019.08.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
In this issue of Cell Host & Microbe, Karlinsey et al. (2019) combine TraDIS with humanized mice to identify genes required for early replication of Salmonella Typhi in vivo. Surprisingly, some expected virulence traits and genes appear dispensable in the replication of S. Typhi, supporting findings from a recent human challenge study by Gibani et al. (2019).
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Affiliation(s)
- Nancy Wang
- Department of Microbiology and Immunology, The University of Melbourne, at the Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, Australia
| | - Leigh A Knodler
- Department of Microbiology and Immunology, The University of Melbourne, at the Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, Australia; Washington State University Paul G. Allen School for Global Animal Health, Pullman, WA, USA
| | - Richard A Strugnell
- Department of Microbiology and Immunology, The University of Melbourne, at the Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, Australia.
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