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Santamaria C, Biegas KJ, Lim PN, Cabral J, Kim CY, Lee JR, Gaidhane IV, Papson C, Gomard-Henshaw K, Rothchild AC, Swarts BM, Siegrist MS. Trehalose dimycolate inhibits phagosome maturation and promotes intracellular M. tuberculosis growth via noncanonical SNARE interactions. Proc Natl Acad Sci U S A 2025; 122:e2423292122. [PMID: 40354525 DOI: 10.1073/pnas.2423292122] [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: 11/12/2024] [Accepted: 03/26/2025] [Indexed: 05/14/2025] Open
Abstract
Mycobacterial cell envelopes are rich in unusual lipids and glycans that play key roles during infection and vaccination. The most abundant envelope glycolipid is trehalose dimycolate (TDM). TDM compromises the host response to mycobacterial species via multiple mechanisms, including inhibition of phagosome maturation. The molecular mechanism by which TDM inhibits phagosome maturation has been elusive. We find that a clickable, photoaffinity TDM probe recapitulates key phenotypes of native TDM in macrophage host cells and binds several host Soluble N-ethylmaleimide-Sensitive Factor Attachment Proteins Receptor (SNARE) proteins, including Vesicle Transport through Interaction with t-SNAREs 1B (VTI1B), Syntaxin 8 (STX8), and Vesicle-Associated Membrane Protein 2 (VAMP2). VTI1B and STX8 normally promote endosome fusion by forming a complex with VAMP8. However, in the presence of Mycobacterium tuberculosis, VTI1B and STX8 complex with VAMP2, which in turn decreases VAMP8 binding. VAMP2 acts together with mycolate structure to inhibit phagosome maturation and promotes intracellular M. tuberculosis replication. Thus one mechanism by which TDM constrains the innate immune response to M. tuberculosis is via noncanonical SNARE complexation.
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Affiliation(s)
- Carolina Santamaria
- Molecular and Cellular Biology Program, College of Natural Sciences, University of Massachusetts, Amherst, MA 01003
- Department of Microbiology, University of Massachusetts, Amherst, MA 01003
| | - Kyle J Biegas
- Department of Chemistry and Biochemistry, Central Michigan University, Mount Pleasant, MI 48859
- Biochemistry, Cell, and Molecular Biology Graduate Program, College of Science and Engineering, Central Michigan University, Mount Pleasant, MI 48859
| | - Pamelia N Lim
- Molecular and Cellular Biology Program, College of Natural Sciences, University of Massachusetts, Amherst, MA 01003
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, MA 01003
| | - Jessica Cabral
- Department of Microbiology, University of Massachusetts, Amherst, MA 01003
| | - Christi Y Kim
- Department of Microbiology, University of Massachusetts, Amherst, MA 01003
| | - James R Lee
- Department of Microbiology, University of Massachusetts, Amherst, MA 01003
| | - Ishani V Gaidhane
- Department of Chemistry and Biochemistry, Central Michigan University, Mount Pleasant, MI 48859
| | - Casey Papson
- Department of Chemistry and Biochemistry, Central Michigan University, Mount Pleasant, MI 48859
| | - Kyla Gomard-Henshaw
- Molecular and Cellular Biology Program, College of Natural Sciences, University of Massachusetts, Amherst, MA 01003
- Department of Microbiology, University of Massachusetts, Amherst, MA 01003
| | - Alissa C Rothchild
- Molecular and Cellular Biology Program, College of Natural Sciences, University of Massachusetts, Amherst, MA 01003
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, MA 01003
| | - Benjamin M Swarts
- Department of Chemistry and Biochemistry, Central Michigan University, Mount Pleasant, MI 48859
- Biochemistry, Cell, and Molecular Biology Graduate Program, College of Science and Engineering, Central Michigan University, Mount Pleasant, MI 48859
| | - M Sloan Siegrist
- Molecular and Cellular Biology Program, College of Natural Sciences, University of Massachusetts, Amherst, MA 01003
- Department of Microbiology, University of Massachusetts, Amherst, MA 01003
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2
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Zhang W, Zhang H, He T, Li X, Liu Y, Han H, Wang J. The diverse functions of syntaxin 13 in endosome-mediated membrane fusion. Int J Biol Macromol 2025; 307:141878. [PMID: 40058431 DOI: 10.1016/j.ijbiomac.2025.141878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2025] [Revised: 03/04/2025] [Accepted: 03/07/2025] [Indexed: 03/14/2025]
Abstract
SNARE is a crucial membrane fusion factor. It forms SNARE complex that play significant roles in regulating various biological functions. The SNARE protein family, including syntaxin13 (STX13), is highly conserved across various species, from yeast to humans. This review summarizes the molecular mechanisms by which STX13-associated SNARE complexes contribute to diverse endosome-mediated membrane fusions. Furthermore, multiple cofactors are essential for regulating the SNARE complexes-mediated membrane fusion. These include but are not limited to Rab GTPases and their effectors. The interaction of these factors with SNARE proteins constitutes a critical component driving vesicle fusion processes.
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Affiliation(s)
- Wenting Zhang
- College of Chemistry and Life Science, Beijing University of Technology, 100 Pingleyuan, Chaoyang District, Beijing 100124, China
| | - Haolin Zhang
- College of Chemistry and Life Science, Beijing University of Technology, 100 Pingleyuan, Chaoyang District, Beijing 100124, China
| | - Tianlong He
- College of Chemistry and Life Science, Beijing University of Technology, 100 Pingleyuan, Chaoyang District, Beijing 100124, China
| | - Xianghua Li
- College of Chemistry and Life Science, Beijing University of Technology, 100 Pingleyuan, Chaoyang District, Beijing 100124, China
| | - Yukun Liu
- College of Chemistry and Life Science, Beijing University of Technology, 100 Pingleyuan, Chaoyang District, Beijing 100124, China
| | - Huijie Han
- College of Chemistry and Life Science, Beijing University of Technology, 100 Pingleyuan, Chaoyang District, Beijing 100124, China.
| | - Juan Wang
- College of Chemistry and Life Science, Beijing University of Technology, 100 Pingleyuan, Chaoyang District, Beijing 100124, China.
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3
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Zhao H, Zhang X, Zhang N, Zhu L, Lian H. The interplay between Salmonella and host: Mechanisms and strategies for bacterial survival. CELL INSIGHT 2025; 4:100237. [PMID: 40177681 PMCID: PMC11964643 DOI: 10.1016/j.cellin.2025.100237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2024] [Revised: 01/20/2025] [Accepted: 01/21/2025] [Indexed: 04/05/2025]
Abstract
Salmonella, an intracellular pathogen, infects both humans and animals, causing diverse diseases such as gastroenteritis and enteric fever. The Salmonella type III secretion system (T3SS), encoded within its pathogenicity islands (SPIs), is critical for bacterial virulence by directly delivering multiple effectors into eukaryotic host cells. Salmonella utilizes these effectors to facilitate its survival and replication within the host through modulating cytoskeletal dynamics, inflammatory responses, the biogenesis of Salmonella-containing vacuole (SCV), and host cell survival. Moreover, these effectors also interfere with immune responses via inhibiting innate immunity or antigen presentation. In this review, we summarize the current progress in the survival strategies employed by Salmonella and the molecular mechanisms underlying its interactions with the host. Understanding the interplay between Salmonella and host can enhance our knowledge of the bacterium's pathogenic processes and provide new insights into how it manipulates host cellular physiological activities to ensure its survival.
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Affiliation(s)
- Hongyu Zhao
- Department of Laboratory Medicine, Zhongnan Hospital of Wuhan University, Medical Research Institute, Frontier Science Center for Immunology and Metabolism, Wuhan University, Wuhan 430071, Hubei, China
| | - Xinyue Zhang
- Department of Laboratory Medicine, Zhongnan Hospital of Wuhan University, Medical Research Institute, Frontier Science Center for Immunology and Metabolism, Wuhan University, Wuhan 430071, Hubei, China
| | - Ningning Zhang
- Yale Stem Cell Center, New Haven, CT, 06520, USA
- Department of Genetics, Yale University School of Medicine, New Haven, CT, 06510, USA
- Yale Cooperative Center of Excellence in Hematology, New Haven, CT, 12208, USA
| | - Li Zhu
- Department of Internal Medicine, Section of Infectious Diseases, Yale University School of Medicine, New Haven, CT, 06511, USA
| | - Huan Lian
- Department of Laboratory Medicine, Zhongnan Hospital of Wuhan University, Medical Research Institute, Frontier Science Center for Immunology and Metabolism, Wuhan University, Wuhan 430071, Hubei, China
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4
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Chakraborty S, Ganguli D, Nagaraja T, Gope A, Dey S, Pal A, Mandal RS, Das SS, Das S. Salmonella Typhi serine threonine kinase T4519 induces lysosomal membrane permeabilization by manipulating Toll-like receptor 2-Cystatin B-Cathepsin B-NF-κB-reactive oxygen species pathway and promotes survival within human macrophages. PLoS Pathog 2025; 21:e1013041. [PMID: 40168426 PMCID: PMC11984733 DOI: 10.1371/journal.ppat.1013041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2024] [Revised: 04/10/2025] [Accepted: 03/12/2025] [Indexed: 04/03/2025] Open
Abstract
Intracellular pathogens of Salmonella spp. survive and replicate within the phagosomes, called Salmonella-containing vacuoles (SCVs) inside macrophages by manipulating phagosomal maturation and phagolysosome formation. While controversies exist about the phagosomal traffic of Salmonella Typhimurium, little studies were carried out with the intracellular survival mechanisms of Salmonella Typhi (S. Typhi). We had previously reported that a eukaryote-like serine/threonine kinase of S. Typhi (T4519) contributes to survival within macrophages and activates host pro-inflammatory signaling pathways regulated by NF-κB. However, neither the mechanisms underlying NF-κB activation nor how it contributes to intracellular survival of S. Typhi were studied. Here we show, by using antibody-mediated blocking and gene knockdown studies that T4519 activates Toll-like receptor 2 (TLR2) signals in the human monocyte-derived macrophages. We computationally predicted the NH2-terminal glycine rich repeat domain of T4519 as the TLR2-binding moiety and confirmed the interaction by co-immunoprecipitation experiment. TLR2-T4519 interaction transcriptionally repressed cystatin B, a cathepsin B inhibitor, leading to the activation of cytosolic cathepsin B, leaked from the lysosomes of the infected cells. Through a series of RT-qPCR, western blotting, gene knockdown, flow cytometry and confocal microscopy experiments, we have shown that active cytosolic cathepsin B cleaves IKB-α, resulting in nuclear translocation of NF-κB and transactivation of its target genes, including reactive oxygen species (ROS), which in turn induces lysosomal membrane permeabilization (LMP). TLR2-dependent targeting of the cystatin B-cathepsin B-NF-κB-ROS pathways by T4519, leading to LMP promotes phagosomal survival of S. Typhi. This study describes a unique mechanism of the exploitation of host NF-κB signaling pathways by bacterial pathogens to promote its own persistence within macrophage cells.
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Affiliation(s)
- Swarnali Chakraborty
- Department of Clinical Medicine, ICMR - National Institute for Research in Bacterial Infections, Kolkata, West Bengal, India
| | - Debayan Ganguli
- Division of Infectious Diseases, Washington school of medicine, St. Louis, Missouri, United States of America
| | - Theeya Nagaraja
- Biocon Biologics Limited- R&D centre, Chennai, Tamil Nadu, India
| | - Animesh Gope
- Department of Clinical Medicine, ICMR - National Institute for Research in Bacterial Infections, Kolkata, West Bengal, India
| | - Sudip Dey
- Department of Clinical Medicine, ICMR - National Institute for Research in Bacterial Infections, Kolkata, West Bengal, India
| | - Ananda Pal
- Department of Clinical Medicine, ICMR - National Institute for Research in Bacterial Infections, Kolkata, West Bengal, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh, India.
| | - Rahul Shubhra Mandal
- Department of Cancer Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Sudipta Sekhar Das
- Department of Cancer, Apollo Multispeciality Hospitals Limited, Kolkata, West Bengal, India
| | - Santasabuj Das
- Department of Clinical Medicine, ICMR - National Institute for Research in Bacterial Infections, Kolkata, West Bengal, India
- ICMR-National Institute of Occupational Health, Ahmedabad, Gujarat, India
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5
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Santamaria C, Biegas KJ, Lim PN, Cabral J, Kim CY, Lee JR, Gaidhane IV, Papson C, Gomard-Henshaw K, Rothchild AC, Swarts BM, Siegrist MS. Trehalose dimycolate inhibits phagosome maturation and promotes intracellular M. tuberculosis growth via noncanonical SNARE interaction. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2025:2024.12.16.627577. [PMID: 39763847 PMCID: PMC11702582 DOI: 10.1101/2024.12.16.627577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/02/2025]
Abstract
Mycobacterial cell envelopes are rich in unusual lipids and glycans that play key roles during infection and vaccination. The most abundant envelope glycolipid is trehalose dimycolate (TDM). TDM compromises the host response to mycobacterial species via multiple mechanisms, including inhibition of phagosome maturation. The molecular mechanism by which TDM inhibits phagosome maturation has been elusive. We find that a clickable, photoaffinity TDM probe recapitulates key phenotypes of native TDM in macrophage host cells and binds several host SNARE proteins, including VTI1B, STX8, and VAMP2. VTI1B and STX8 normally promote endosome fusion by forming a complex with VAMP8. However, in the presence of Mycobacterium tuberculosis , VTI1B and STX8 complex with VAMP2, which in turn decreases VAMP8 binding. VAMP2 acts together with mycolate structure to inhibit phagosome maturation and promotes intracellular M. tuberculosis replication. Thus one mechanism by which TDM constrains the innate immune response to M. tuberculosis is via non-canonical SNARE complexation. Significance Statement Glycolipids from the Mycobacterium tuberculosis cell envelope, particularly trehalose dimycolate (TDM), play major roles in subverting the immune response to this intracellular pathogen. How subversion occurs is often unclear because glycans and lipids are technically challenging to study in cells. We discovered that a TDM-mimicking chemical probe interacts with three host SNARE proteins, including two that regulate endosome fusion and one that does not. The presence of TDM or M. tuberculosis triggers abnormal binding of these SNAREs, which in turn inhibits the fusion of M. tuberculosis -containing phagosomes with lysosomes and promotes M. tuberculosis replication. Our work provides an unusual example of a bacterial pathogen restricting the immune response via glycolipid-SNARE interactions.
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Birk MS, Walch P, Baykara T, Sefried S, Amelang J, Buerova E, Breuer I, Vervoots J, Typas A, Savitski MM, Mateus A, Selkrig J. Salmonella infection impacts host proteome thermal stability. Eur J Cell Biol 2024; 103:151448. [PMID: 39128247 DOI: 10.1016/j.ejcb.2024.151448] [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: 08/21/2023] [Revised: 07/31/2024] [Accepted: 08/03/2024] [Indexed: 08/13/2024] Open
Abstract
Intracellular bacterial pathogens hijack the protein machinery of infected host cells to evade their defenses and cultivate a favorable intracellular niche. The intracellular pathogen Salmonella enterica subsp. Typhimurium (STm) achieves this by injecting a cocktail of effector proteins into host cells that modify the activity of target host proteins. Yet, proteome-wide approaches to systematically map changes in host protein function during infection have remained challenging. Here we adapted a functional proteomics approach - Thermal-Proteome Profiling (TPP) - to systematically assess proteome-wide changes in host protein abundance and thermal stability throughout an STm infection cycle. By comparing macrophages treated with live or heat-killed STm, we observed that most host protein abundance changes occur independently of STm viability. In contrast, a large portion of host protein thermal stability changes were specific to infection with live STm. This included pronounced thermal stability changes in proteins linked to mitochondrial function (Acod1/Irg1, Cox6c, Samm50, Vdac1, and mitochondrial respiratory chain complex proteins), as well as the interferon-inducible protein with tetratricopeptide repeats, Ifit1. Integration of our TPP data with a publicly available STm-host protein-protein interaction database led us to discover that the secreted STm effector kinase, SteC, thermally destabilizes and phosphorylates the ribosomal preservation factor Serbp1. In summary, this work emphasizes the utility of measuring protein thermal stability during infection to accelerate the discovery of novel molecular interactions at the host-pathogen interface.
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Affiliation(s)
- Marlène S Birk
- Institute of Medical Microbiology, RWTH University Hospital, Aachen 52074, Germany
| | - Philipp Walch
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, Meyerhofstrasse 1, Heidelberg 69117, Germany
| | - Tarik Baykara
- Institute of Medical Microbiology, RWTH University Hospital, Aachen 52074, Germany
| | - Stephanie Sefried
- Institute of Medical Microbiology, RWTH University Hospital, Aachen 52074, Germany
| | - Jan Amelang
- Institute of Biochemistry and Molecular Biology, RWTH University Hospital, Aachen 52074, Germany
| | - Elena Buerova
- Institute of Biochemistry and Molecular Biology, RWTH University Hospital, Aachen 52074, Germany
| | - Ingrid Breuer
- Institute of Medical Microbiology, RWTH University Hospital, Aachen 52074, Germany
| | - Jörg Vervoots
- Institute of Biochemistry and Molecular Biology, RWTH University Hospital, Aachen 52074, Germany
| | - Athanasios Typas
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, Meyerhofstrasse 1, Heidelberg 69117, Germany
| | - Mikhail M Savitski
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, Meyerhofstrasse 1, Heidelberg 69117, Germany
| | - André Mateus
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, Meyerhofstrasse 1, Heidelberg 69117, Germany; Department of Chemistry, Umeå University, Umeå 907 36, Sweden; The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå 907 36, Sweden.
| | - Joel Selkrig
- Institute of Medical Microbiology, RWTH University Hospital, Aachen 52074, Germany; European Molecular Biology Laboratory (EMBL), Genome Biology Unit, Meyerhofstrasse 1, Heidelberg 69117, Germany.
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7
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Niedzialkowska E, Runyan LA, Kudryashova E, Egelman EH, Kudryashov DS. Stabilization of F-actin by Salmonella effector SipA resembles the structural effects of inorganic phosphate and phalloidin. Structure 2024; 32:725-738.e8. [PMID: 38518780 PMCID: PMC11162321 DOI: 10.1016/j.str.2024.02.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 02/08/2024] [Accepted: 02/26/2024] [Indexed: 03/24/2024]
Abstract
Entry of Salmonella into host enterocytes relies on its pathogenicity island 1 effector SipA. We found that SipA binds to F-actin in a 1:2 stoichiometry with sub-nanomolar affinity. A cryo-EM reconstruction revealed that SipA's globular core binds at the groove between actin strands, whereas the extended C-terminal arm penetrates deeply into the inter-strand space, stabilizing F-actin from within. The unusually strong binding of SipA is achieved by a combination of fast association via the core and very slow dissociation dictated by the arm. Similar to Pi, BeF3, and phalloidin, SipA potently inhibited actin depolymerization by actin depolymerizing factor (ADF)/cofilin, which correlated with increased filament stiffness, supporting the hypothesis that F-actin's mechanical properties contribute to the recognition of its nucleotide state by protein partners. The remarkably strong binding to F-actin maximizes the toxin's effects at the injection site while minimizing global influence on the cytoskeleton and preventing pathogen detection by the host cell.
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Affiliation(s)
- Ewa Niedzialkowska
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22903, USA
| | - Lucas A Runyan
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
| | - Elena Kudryashova
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
| | - Edward H Egelman
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22903, USA.
| | - Dmitri S Kudryashov
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA.
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8
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Chatterjee R, Setty SRG, Chakravortty D. SNAREs: a double-edged sword for intravacuolar bacterial pathogens within host cells. Trends Microbiol 2024; 32:477-493. [PMID: 38040624 DOI: 10.1016/j.tim.2023.11.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2023] [Revised: 11/07/2023] [Accepted: 11/08/2023] [Indexed: 12/03/2023]
Abstract
In the tug-of-war between host and pathogen, both evolve to combat each other's defence arsenals. Intracellular phagosomal bacteria have developed strategies to modify the vacuolar niche to suit their requirements best. Conversely, the host tries to target the pathogen-containing vacuoles towards the degradative pathways. The host cells use a robust system through intracellular trafficking to maintain homeostasis inside the cellular milieu. In parallel, intracellular bacterial pathogens have coevolved with the host to harbour strategies to manipulate cellular pathways, organelles, and cargoes, facilitating the conversion of the phagosome into a modified pathogen-containing vacuole (PCV). Key molecular regulators of intracellular traffic, such as changes in the organelle (phospholipid) composition, recruitment of small GTPases and associated effectors, soluble N-ethylmaleimide-sensitive factor-activating protein receptors (SNAREs), etc., are hijacked to evade lysosomal degradation. Legionella, Salmonella, Coxiella, Chlamydia, Mycobacterium, and Brucella are examples of pathogens which diverge from the endocytic pathway by using effector-mediated mechanisms to overcome the challenges and establish their intracellular niches. These pathogens extensively utilise and modulate the end processes of secretory pathways, particularly SNAREs, in repurposing the PCV into specialised compartments resembling the host organelles within the secretory network; at the same time, they avoid being degraded by the host's cellular mechanisms. Here, we discuss the recent research advances on the host-pathogen interaction/crosstalk that involves host SNAREs, conserved cellular processes, and the ongoing host-pathogen defence mechanisms in the molecular arms race against each other. The current knowledge of SNAREs, and intravacuolar bacterial pathogen interactions, enables us to understand host cellular innate immune pathways, maintenance of homeostasis, and potential therapeutic strategies to combat ever-growing antimicrobial resistance.
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Affiliation(s)
- Ritika Chatterjee
- Department of Microbiology and Cell Biology, Division of Biological Sciences, Indian Institute of Science, Bangalore, Karnataka, India
| | - Subba Rao Gangi Setty
- Department of Microbiology and Cell Biology, Division of Biological Sciences, Indian Institute of Science, Bangalore, Karnataka, India.
| | - Dipshikha Chakravortty
- Department of Microbiology and Cell Biology, Division of Biological Sciences, Indian Institute of Science, Bangalore, Karnataka, India; Adjunct Faculty, Indian Institute of Science Research and Education, Thiruvananthapuram, Kerala, India.
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9
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Sood C, Verma JK, Basak R, Kapoor A, Gupta S, Mukhopadhyay A. Leishmania highjack host lipid body for its proliferation in macrophages by overexpressing host Rab18 and TRAPPC9 by downregulating miR-1914-3p expression. PLoS Pathog 2024; 20:e1012024. [PMID: 38412149 PMCID: PMC10898768 DOI: 10.1371/journal.ppat.1012024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Accepted: 02/05/2024] [Indexed: 02/29/2024] Open
Abstract
Lipids stored in lipid-bodies (LBs) in host cells are potential sources of fatty acids for pathogens. However, the mechanism of recruitment of LBs from the host cells by pathogens to acquire fatty acids is not known. Here, we have found that Leishmania specifically upregulates the expression of host Rab18 and its GEF, TRAPPC9 by downregulating the expression of miR-1914-3p by reducing the level of Dicer in macrophages via their metalloprotease gp63. Our results also show that miR-1914-3p negatively regulates the expression of Rab18 and its GEF in cells. Subsequently, Leishmania containing parasitophorous vacuoles (Ld-PVs) recruit and retain host Rab18 and TRAPPC9. Leishmania infection also induces LB biogenesis in host cells and recruits LBs on Ld-PVs and acquires FLC12-labeled fatty acids from LBs. Moreover, overexpression of miR-1914-3p in macrophages significantly inhibits the recruitment of LBs and thereby suppresses the multiplication of parasites in macrophages as parasites are unable to acquire fatty acids. These results demonstrate a novel mechanism how Leishmania acquire fatty acids from LBs for their growth in macrophages.
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Affiliation(s)
- Chandni Sood
- National Institute of Immunology, New Delhi, India
| | - Jitender Kumar Verma
- Kusuma School of Biological Sciences, Indian Institute of Technology, Hauz Khas, New Delhi, India
- National Institute of Immunology, New Delhi, India
| | - Rituparna Basak
- Kusuma School of Biological Sciences, Indian Institute of Technology, Hauz Khas, New Delhi, India
| | - Anjali Kapoor
- Kusuma School of Biological Sciences, Indian Institute of Technology, Hauz Khas, New Delhi, India
| | - Swarnima Gupta
- Kusuma School of Biological Sciences, Indian Institute of Technology, Hauz Khas, New Delhi, India
| | - Amitabha Mukhopadhyay
- Kusuma School of Biological Sciences, Indian Institute of Technology, Hauz Khas, New Delhi, India
- National Institute of Immunology, New Delhi, India
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10
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Liu X, Liu Y, Zhao X, Li X, Yao T, Liu R, Wang Q, Wang Q, Li D, Chen X, Liu B, Feng L. Salmonella enterica serovar Typhimurium remodels mitochondrial dynamics of macrophages via the T3SS effector SipA to promote intracellular proliferation. Gut Microbes 2024; 16:2316932. [PMID: 38356294 PMCID: PMC10877990 DOI: 10.1080/19490976.2024.2316932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Accepted: 02/06/2024] [Indexed: 02/16/2024] Open
Abstract
Mitochondrial dynamics are critical in cellular energy production, metabolism, apoptosis, and immune responses. Pathogenic bacteria have evolved sophisticated mechanisms to manipulate host cells' mitochondrial functions, facilitating their proliferation and dissemination. Salmonella enterica serovar Typhimurium (S. Tm), an intracellular foodborne pathogen, causes diarrhea and exploits host macrophages for survival and replication. However, S. Tm-associated mitochondrial dynamics during macrophage infection remain poorly understood. In this study, we showed that within macrophages, S. Tm remodeled mitochondrial fragmentation to facilitate intracellular proliferation mediated by Salmonella invasion protein A (SipA), a type III secretion system effector encoded by Salmonella pathogenicity island 1. SipA directly targeted mitochondria via its N-terminal mitochondrial targeting sequence, preventing excessive fragmentation and the associated increase in mitochondrial reactive oxygen species, loss of mitochondrial membrane potential, and release of mitochondrial DNA and cytochrome c into the cytosol. Macrophage replication assays and animal experiments showed that mitochondria and SipA interact to facilitate intracellular replication and pathogenicity of S. Tm. Furthermore, we showed that SipA delayed mitochondrial fragmentation by indirectly inhibiting the recruitment of cytosolic dynamin-related protein 1, which mediates mitochondrial fragmentation. This study revealed a novel mechanism through which S. Tm manipulates host mitochondrial dynamics, providing insights into the molecular interplay that facilitates S. Tm adaptation within host macrophages.
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Affiliation(s)
- Xingmei Liu
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, China
- Key Laboratory of Molecular Microbiology and Technology, Nankai University, Tianjin, China
| | - Yutao Liu
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, China
- Key Laboratory of Molecular Microbiology and Technology, Nankai University, Tianjin, China
| | - Xinyu Zhao
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, China
- Key Laboratory of Molecular Microbiology and Technology, Nankai University, Tianjin, China
| | - Xueping Li
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, China
- Key Laboratory of Molecular Microbiology and Technology, Nankai University, Tianjin, China
| | - Ting Yao
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, China
- Key Laboratory of Molecular Microbiology and Technology, Nankai University, Tianjin, China
| | - Ruiying Liu
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, China
- Key Laboratory of Molecular Microbiology and Technology, Nankai University, Tianjin, China
| | - Qian Wang
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, China
- Key Laboratory of Molecular Microbiology and Technology, Nankai University, Tianjin, China
| | - Qiushi Wang
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, China
- Key Laboratory of Molecular Microbiology and Technology, Nankai University, Tianjin, China
| | - Dan Li
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, China
- Key Laboratory of Molecular Microbiology and Technology, Nankai University, Tianjin, China
| | - Xintong Chen
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, China
- Key Laboratory of Molecular Microbiology and Technology, Nankai University, Tianjin, China
| | - Bin Liu
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, China
- Key Laboratory of Molecular Microbiology and Technology, Nankai University, Tianjin, China
- Nankai International Advanced Research Institute, Nankai University Shenzhen, Shenzhen, China
| | - Lu Feng
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, China
- Key Laboratory of Molecular Microbiology and Technology, Nankai University, Tianjin, China
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11
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Niedzialkowska E, Runyan LA, Kudryashova E, Egelman EH, Kudryashov DS. Stabilization of F-actin by Salmonella effector SipA resembles the structural effects of inorganic phosphate and phalloidin. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.26.573373. [PMID: 38234808 PMCID: PMC10793455 DOI: 10.1101/2023.12.26.573373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
Entry of Salmonella into host enterocytes strictly relies on its pathogenicity island 1 effector SipA. We found that SipA binds to F-actin in a unique mode in a 1:2 stoichiometry with picomolar affinity. A cryo-EM reconstruction revealed that SipA's globular core binds at the grove between actin strands, whereas the extended C-terminal arm penetrates deeply into the inter-strand space, stabilizing F-actin from within. The unusually strong binding of SipA is achieved via a combination of fast association via the core and very slow dissociation dictated by the arm. Similarly to Pi, BeF3, and phalloidin, SipA potently inhibited actin depolymerization by ADF/cofilin, which correlated with the increased filament stiffness, supporting the hypothesis that F-actin's mechanical properties contribute to the recognition of its nucleotide state by protein partners. The remarkably strong binding to F-actin maximizes the toxin's effects at the injection site while minimizing global influence on the cytoskeleton and preventing pathogen detection by the host cell.
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Affiliation(s)
- Ewa Niedzialkowska
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22903, USA
| | - Lucas A. Runyan
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
| | - Elena Kudryashova
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
| | - Edward H. Egelman
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22903, USA
| | - Dmitri S. Kudryashov
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
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12
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Berni M, Bolzoni L, Menozzi I, Dodi A, Bracchi C, Morganti M, Scaltriti E, Pongolini S, Tambassi M. Salmonella Derby adaptation to swine and simultaneous attenuation for humans go through decay of Salmonella Pathogenicity Island I. Microbiol Spectr 2023; 11:e0189923. [PMID: 37800927 PMCID: PMC10715017 DOI: 10.1128/spectrum.01899-23] [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: 05/19/2023] [Accepted: 08/09/2023] [Indexed: 10/07/2023] Open
Abstract
IMPORTANCE This study integrated population data with in vitro assessment of virulence phenotypes to unveil that a considerable part of the global population of Salmonella Derby is evolving to enhance its host adaptation to the swine host and that this evolution is simultaneously increasing its attenuation for humans. The study shows that the fixation of deleterious mutations in SPI-1 has a role in this process. This evidence indicates that SPI-1 has a key role for S. Derby virulence in humans but not for its circulation in swine. The results show that genes generally considered essential for Salmonella pathogenesis do not play the same key role for all Salmonella serovars or lineages and/or all hosts. The study helps in understanding the molecular mechanisms underlying the ecology and host adaptation of Salmonella showing that the adaptation process can vary for different types of Salmonella and hosts.
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Affiliation(s)
- Melissa Berni
- Risk Analysis and Genomic Epidemiology Unit, Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia-Romagna (IZSLER), Parma, Italy
| | - Luca Bolzoni
- Risk Analysis and Genomic Epidemiology Unit, Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia-Romagna (IZSLER), Parma, Italy
| | - Ilaria Menozzi
- Risk Analysis and Genomic Epidemiology Unit, Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia-Romagna (IZSLER), Parma, Italy
| | - Alessandra Dodi
- Risk Analysis and Genomic Epidemiology Unit, Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia-Romagna (IZSLER), Parma, Italy
| | - Chiara Bracchi
- Risk Analysis and Genomic Epidemiology Unit, Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia-Romagna (IZSLER), Parma, Italy
| | - Marina Morganti
- Risk Analysis and Genomic Epidemiology Unit, Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia-Romagna (IZSLER), Parma, Italy
| | - Erika Scaltriti
- Risk Analysis and Genomic Epidemiology Unit, Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia-Romagna (IZSLER), Parma, Italy
| | - Stefano Pongolini
- Risk Analysis and Genomic Epidemiology Unit, Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia-Romagna (IZSLER), Parma, Italy
| | - Martina Tambassi
- Risk Analysis and Genomic Epidemiology Unit, Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia-Romagna (IZSLER), Parma, Italy
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13
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Yuan B, Scholz J, Wald J, Thuenauer R, Hennell James R, Ellenberg I, Windhorst S, Faix J, Marlovits TC. Structural basis for subversion of host cell actin cytoskeleton during Salmonella infection. SCIENCE ADVANCES 2023; 9:eadj5777. [PMID: 38064550 PMCID: PMC10708208 DOI: 10.1126/sciadv.adj5777] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Accepted: 11/09/2023] [Indexed: 12/18/2023]
Abstract
Secreted bacterial type III secretion system (T3SS) proteins are essential for successful infection by many human pathogens. Both T3SS translocator SipC and effector SipA are critical for Salmonella infection by subversion of the host cell cytoskeleton, but the precise molecular interplay between them remains unknown. Here, using cryo-electron microscopy, we show that SipA binds along the F-actin grooves with a unique binding pattern. SipA stabilizes F-actin through charged interface residues and appears to prevent inorganic phosphate release through closure of the "back door" of adenosine 5'-triphosphate pocket. We also show that SipC enhances the binding of SipA to F-actin, thus demonstrating that a sequential presence of T3SS proteins in host cells is associated with a sequence of infection events-starting with actin nucleation, filament growth, and stabilization. Together, our data explain the coordinated interplay of a precisely tuned and highly effective mechanism during Salmonella infection and provide a blueprint for interfering with Salmonella effectors acting on actin.
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Affiliation(s)
- Biao Yuan
- University Medical Center Hamburg-Eppendorf (UKE), Institute of Structural and Systems Biology, Hamburg, Germany
- Centre for Structural Systems Biology (CSSB), Hamburg, Germany
- Deutsches Elektronen-Synchrotron Zentrum (DESY), Hamburg, Germany
| | - Jonas Scholz
- Institute for Biophysical Chemistry, Hannover Medical School, Hannover, Germany
| | - Jiri Wald
- University Medical Center Hamburg-Eppendorf (UKE), Institute of Structural and Systems Biology, Hamburg, Germany
- Centre for Structural Systems Biology (CSSB), Hamburg, Germany
- Deutsches Elektronen-Synchrotron Zentrum (DESY), Hamburg, Germany
| | - Roland Thuenauer
- Centre for Structural Systems Biology (CSSB), Hamburg, Germany
- Technology Platform Light Microscopy (TPLM), University of Hamburg, Hamburg, Germany
- Technology Platform Microscopy and Image Analysis (TP MIA), Leibniz Institute of Virology (LIV), Hamburg, Germany
| | - Rory Hennell James
- University Medical Center Hamburg-Eppendorf (UKE), Institute of Structural and Systems Biology, Hamburg, Germany
- Centre for Structural Systems Biology (CSSB), Hamburg, Germany
- Deutsches Elektronen-Synchrotron Zentrum (DESY), Hamburg, Germany
| | - Irina Ellenberg
- University Medical Center Hamburg-Eppendorf (UKE), Institute for Biochemistry and Signal Transduction, Hamburg, Germany
| | - Sabine Windhorst
- University Medical Center Hamburg-Eppendorf (UKE), Institute for Biochemistry and Signal Transduction, Hamburg, Germany
| | - Jan Faix
- Institute for Biophysical Chemistry, Hannover Medical School, Hannover, Germany
| | - Thomas C. Marlovits
- University Medical Center Hamburg-Eppendorf (UKE), Institute of Structural and Systems Biology, Hamburg, Germany
- Centre for Structural Systems Biology (CSSB), Hamburg, Germany
- Deutsches Elektronen-Synchrotron Zentrum (DESY), Hamburg, Germany
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14
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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: 1.0] [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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15
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Chatterjee R, Nair AV, Singh A, Mehta N, Setty SRG, Chakravortty D. Syntaxin 3 SPI-2 dependent crosstalk facilitates the division of Salmonella containing vacuole. Traffic 2023; 24:270-283. [PMID: 37114883 DOI: 10.1111/tra.12887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Accepted: 04/15/2023] [Indexed: 04/29/2023]
Abstract
Intracellular membrane fusion is mediated by membrane-bridging complexes of soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs). SNARE proteins are one of the key players in vesicular transport. Several reports shed light on intracellular bacteria modulating host SNARE machinery to establish infection successfully. The critical SNAREs in macrophages responsible for phagosome maturation are Syntaxin 3 (STX3) and Syntaxin 4 (STX4). Reports also suggest that Salmonella actively modulates its vacuole membrane composition to escape lysosomal fusion. Salmonella containing vacuole (SCV) harbours recycling endosomal SNARE Syntaxin 12 (STX12). However, the role of host SNAREs in SCV biogenesis and pathogenesis remains unclear. Upon knockdown of STX3, we observed a reduction in bacterial proliferation, which is concomitantly restored upon the overexpression of STX3. Live-cell imaging of Salmonella-infected cells showed that STX3 localises to the SCV membranes and thus might help in the fusion of SCV with intracellular vesicles to acquire membrane for its division. We also found the interaction STX3-SCV was abrogated when we infected with SPI-2 encoded Type 3 secretion system (T3SS) apparatus mutant (STM ∆ssaV) but not with SPI-1 encoded T3SS apparatus mutant (STM ∆invC). These observations were also consistent in the mice model of Salmonella infection. Together, these results shed light on the effector molecules secreted through T3SS encoded by SPI-2, possibly involved in interaction with host SNARE STX3, which is essential to maintain the division of Salmonella in SCV and help to maintain a single bacterium per vacuole.
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Affiliation(s)
- Ritika Chatterjee
- Department of Microbiology and Cell Biology, Division of Biological Sciences, Indian Institute of Science, Bangalore, India
| | - Abhilash Vijay Nair
- Department of Microbiology and Cell Biology, Division of Biological Sciences, Indian Institute of Science, Bangalore, India
| | - Anmol Singh
- Department of Microbiology and Cell Biology, Division of Biological Sciences, Indian Institute of Science, Bangalore, India
| | - Nishi Mehta
- Department of Microbiology and Cell Biology, Division of Biological Sciences, Indian Institute of Science, Bangalore, India
| | - Subba Rao Gangi Setty
- Department of Microbiology and Cell Biology, Division of Biological Sciences, Indian Institute of Science, Bangalore, India
| | - Dipshikha Chakravortty
- Department of Microbiology and Cell Biology, Division of Biological Sciences, Indian Institute of Science, Bangalore, India
- School of Biology, Indian Institute of Science Education and Research, Thiruvananthapuram, Kerala, India
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16
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Pillay TD, Hettiarachchi SU, Gan J, Diaz-Del-Olmo I, Yu XJ, Muench JH, Thurston TL, Pearson JS. Speaking the host language: how Salmonella effector proteins manipulate the host. MICROBIOLOGY (READING, ENGLAND) 2023; 169:001342. [PMID: 37279149 PMCID: PMC10333799 DOI: 10.1099/mic.0.001342] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2023] [Accepted: 05/10/2023] [Indexed: 06/08/2023]
Abstract
Salmonella injects over 40 virulence factors, termed effectors, into host cells to subvert diverse host cellular processes. Of these 40 Salmonella effectors, at least 25 have been described as mediating eukaryotic-like, biochemical post-translational modifications (PTMs) of host proteins, altering the outcome of infection. The downstream changes mediated by an effector's enzymatic activity range from highly specific to multifunctional, and altogether their combined action impacts the function of an impressive array of host cellular processes, including signal transduction, membrane trafficking, and both innate and adaptive immune responses. Salmonella and related Gram-negative pathogens have been a rich resource for the discovery of unique enzymatic activities, expanding our understanding of host signalling networks, bacterial pathogenesis as well as basic biochemistry. In this review, we provide an up-to-date assessment of host manipulation mediated by the Salmonella type III secretion system injectosome, exploring the cellular effects of diverse effector activities with a particular focus on PTMs and the implications for infection outcomes. We also highlight activities and functions of numerous effectors that remain poorly characterized.
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Affiliation(s)
- Timesh D. Pillay
- Centre for Bacterial Resistance Biology, Department of Infectious Disease, Imperial College, London SW7 2AZ, UK
- The Francis Crick Institute, London NW1 1AT, UK
| | - Sahampath U. Hettiarachchi
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, Victoria, Australia
- Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - Jiyao Gan
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, Victoria, Australia
| | - Ines Diaz-Del-Olmo
- Centre for Bacterial Resistance Biology, Department of Infectious Disease, Imperial College, London SW7 2AZ, UK
| | - Xiu-Jun Yu
- Centre for Bacterial Resistance Biology, Department of Infectious Disease, Imperial College, London SW7 2AZ, UK
| | - Janina H. Muench
- Centre for Bacterial Resistance Biology, Department of Infectious Disease, Imperial College, London SW7 2AZ, UK
- The Francis Crick Institute, London NW1 1AT, UK
| | - Teresa L.M. Thurston
- Centre for Bacterial Resistance Biology, Department of Infectious Disease, Imperial College, London SW7 2AZ, UK
- The Francis Crick Institute, London NW1 1AT, UK
| | - Jaclyn S. Pearson
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, Victoria, Australia
- Department of Microbiology, Monash University, Clayton, Victoria, Australia
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17
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Zhou G, Zhao Y, Ma Q, Li Q, Wang S, Shi H. Manipulation of host immune defenses by effector proteins delivered from multiple secretion systems of Salmonella and its application in vaccine research. Front Immunol 2023; 14:1152017. [PMID: 37081875 PMCID: PMC10112668 DOI: 10.3389/fimmu.2023.1152017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 03/23/2023] [Indexed: 04/07/2023] Open
Abstract
Salmonella is an important zoonotic bacterial species and hazardous for the health of human beings and livestock globally. Depending on the host, Salmonella can cause diseases ranging from gastroenteritis to life-threatening systemic infection. In this review, we discuss the effector proteins used by Salmonella to evade or manipulate four different levels of host immune defenses: commensal flora, intestinal epithelial-mucosal barrier, innate and adaptive immunity. At present, Salmonella has evolved a variety of strategies against host defense mechanisms, among which various effector proteins delivered by the secretory systems play a key role. During its passage through the digestive system, Salmonella has to face the intact intestinal epithelial barrier as well as competition with commensal flora. After invasion of host cells, Salmonella manipulates inflammatory pathways, ubiquitination and autophagy processes with the help of effector proteins. Finally, Salmonella evades the adaptive immune system by interfering the migration of dendritic cells and interacting with T and B lymphocytes. In conclusion, Salmonella can manipulate multiple aspects of host defense to promote its replication in the host.
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Affiliation(s)
- Guodong Zhou
- College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, China
- Jiangsu Co-innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
| | - Yuying Zhao
- College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, China
- Jiangsu Co-innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
| | - Qifeng Ma
- College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, China
- Jiangsu Co-innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
| | - Quan Li
- College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, China
- Jiangsu Co-innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
| | - Shifeng Wang
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, FL, United States
| | - Huoying Shi
- College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, China
- Jiangsu Co-innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety, Yangzhou University (JIRLAAPS), Yangzhou, China
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18
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Ganesan S, Alvarez NN, Steiner S, Fowler KM, Corona AK, Roy CR. Syntaxin 11 Contributes to the Interferon-Inducible Restriction of Coxiella burnetii Intracellular Infection. mBio 2023; 14:e0354522. [PMID: 36728431 PMCID: PMC9972978 DOI: 10.1128/mbio.03545-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Accepted: 01/04/2023] [Indexed: 02/03/2023] Open
Abstract
There is a limited understanding of host defense mechanisms targeting intracellular pathogens that proliferate in a lysosome. Coxiella burnetii is a model bacterial pathogen capable of replicating in the hydrolytic and acidic environment of the lysosome. It has been shown that gamma interferon (IFNγ)-stimulated host cells restrict C. burnetii replication by a mechanism that involves host IDO1 depletion of tryptophan. Host cells deficient in IDO1 activity, however, retain the ability to restrict C. burnetii replication when stimulated with IFNγ, which suggests additional mechanisms of host defense. This study identified syntaxin 11 (STX11) as a host protein that contributes to IFNγ-mediated suppression of C. burnetii replication. STX11 is a SNARE protein; SNARE proteins are proteins that mediate fusion of host vesicles with specific subcellular organelles. Depletion of STX11 using either small interfering RNA (siRNA)- or CRISPR-based approaches enhanced C. burnetii replication intracellularly. Stable expression of STX11 reduced C. burnetii replication in epithelial cells and macrophages, which indicates that this STX11-dependent cell-autonomous response is operational in multiple cell types and can function independently of other IFNγ-induced factors. Fluorescently tagged STX11 localized to the Coxiella-containing vacuole (CCV), and STX11 restriction was found to involve an interaction with STX8. Thus, STX11 regulates a vesicle fusion pathway that limits replication of this intracellular pathogen in a lysosome-derived organelle. IMPORTANCE Cell intrinsic defense mechanisms are used by eukaryotic cells to restrict the replication and dissemination of pathogens. This study identified a human protein called syntaxin 11 (STX11) as a host restriction factor that inhibits the intracellular replication of Coxiella burnetii. Syntaxins regulate the delivery of cargo inside vesicles by promoting specific membrane fusion events between donor and acceptor vesicles. Data presented here demonstrate that STX11 regulates an immunological defense pathway that controls replication of pathogens in lysosome-derived organelles, which provides new insight into the function of this SNARE protein.
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Affiliation(s)
- Sandhya Ganesan
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Natalie N. Alvarez
- Department of Pediatrics, School of Medicine, Emory University, Atlanta, Georgia, USA
| | - Samuel Steiner
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Karen M. Fowler
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Abigail K. Corona
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Craig R. Roy
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut, USA
- Department of Immunobiology, Yale University School of Medicine, New Haven, Connecticut, USA
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19
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Murine AML12 hepatocytes allow Salmonella Typhimurium T3SS1-independent invasion and intracellular fate. Sci Rep 2021; 11:22803. [PMID: 34815429 PMCID: PMC8611075 DOI: 10.1038/s41598-021-02054-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 11/01/2021] [Indexed: 11/08/2022] Open
Abstract
Numerous studies have demonstrated the key role of the Salmonella Pathogenicity Island 1-encoded type III secretion system (T3SS1) apparatus as well as its associated effectors in the invasion and intracellular fate of Salmonella in the host cell. Several T3SS1 effectors work together to control cytoskeleton networks and induce massive membrane ruffles, allowing pathogen internalization. Salmonella resides in a vacuole whose maturation requires that the activity of T3SS1 subverts early stages of cell signaling. Recently, we identified five cell lines in which Salmonella Typhimurium enters without using its three known invasion factors: T3SS1, Rck and PagN. The present study investigated the intracellular fate of Salmonella Typhimurium in one of these models, the murine hepatocyte cell line AML12. We demonstrated that both wild-type Salmonella and T3SS1-invalidated Salmonella followed a common pathway leading to the formation of a Salmonella containing vacuole (SCV) without classical recruitment of Rho-GTPases. Maturation of the SCV continued through an acidified phase that led to Salmonella multiplication as well as the formation of a tubular network resembling Salmonella induced filaments (SIF). The fact that in the murine AML12 hepatocyte, the T3SS1 mutant induced an intracellular fate resembling to the wild-type strain highlights the fact that Salmonella Typhimurium invasion and intracellular survival can be completely independent of T3SS1.
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20
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Developing Cyclic Peptomers as Broad-Spectrum Type III Secretion System Inhibitors in Gram-Negative Bacteria. Antimicrob Agents Chemother 2021; 65:e0169020. [PMID: 33875435 PMCID: PMC8373237 DOI: 10.1128/aac.01690-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Antibiotic-resistant bacteria are an emerging global health threat. New antimicrobials are urgently needed. The injectisome type III secretion system (T3SS), required by dozens of Gram-negative bacteria for virulence but largely absent from nonpathogenic bacteria, is an attractive antimicrobial target. We previously identified synthetic cyclic peptomers, inspired by the natural product phepropeptin D, that inhibit protein secretion through the Yersinia Ysc and Pseudomonas aeruginosa Psc T3SSs but do not inhibit bacterial growth. Here, we describe the identification of an isomer, 4EpDN, that is 2-fold more potent (50% inhibitory concentration [IC50] of 4 μM) than its parental compound. Furthermore, 4EpDN inhibited the Yersinia Ysa and the Salmonella SPI-1 T3SSs, suggesting that this cyclic peptomer has broad efficacy against evolutionarily distant injectisome T3SSs. Indeed, 4EpDN strongly inhibited intracellular growth of Chlamydia trachomatis in HeLa cells, which requires the T3SS. 4EpDN did not inhibit the unrelated twin arginine translocation (Tat) system, nor did it impact T3SS gene transcription. Moreover, although the injectisome and flagellar T3SSs are evolutionarily and structurally related, the 4EpDN cyclic peptomer did not inhibit secretion of substrates through the Salmonella flagellar T3SS, indicating that cyclic peptomers broadly but specifically target the injectisome T3SS. 4EpDN reduced the number of T3SS needles detected on the surface of Yersinia pseudotuberculosis as detected by microscopy. Collectively, these data suggest that cyclic peptomers specifically inhibit the injectisome T3SS from a variety of Gram-negative bacteria, possibly by preventing complete T3SS assembly.
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21
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Positive regulation of Type III secretion effectors and virulence by RyhB paralogs in Salmonella enterica serovar Enteritidis. Vet Res 2021; 52:44. [PMID: 33691799 PMCID: PMC7944605 DOI: 10.1186/s13567-021-00915-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 02/17/2021] [Indexed: 01/02/2023] Open
Abstract
Small non-coding RNA RyhB is a key regulator of iron homeostasis in bacteria by sensing iron availability in the environment. Although RyhB is known to influence bacterial virulence by interacting with iron metabolism related regulators, its interaction with virulence genes, especially the Type III secretion system (T3SS), has not been reported. Here, we demonstrate that two RyhB paralogs of Salmonella enterica serovar Enteritidis upregulate Type III secretion system (T3SS) effectors, and consequently affect Salmonella invasion into intestinal epithelial cells. Specifically, we found that RyhB-1 modulate Salmonella response to stress condition of iron deficiency and hypoxia, and stress in simulated intestinal environment (SIE). Under SIE culture conditions, both RyhB-1 and RyhB-2 are drastically induced and directly upregulate the expression of T3SS effector gene sipA by interacting with its 5′ untranslated region (5′ UTR) via an incomplete base-pairing mechanism. In addition, the RyhB paralogs upregulate the expression of T3SS effector gene sopE. By regulating the invasion-related genes, RyhBs in turn affect the ability of S. Enteritidis to adhere to and invade into intestinal epithelial cells. Our findings provide evidence that RyhBs function as critical virulence factors by directly regulating virulence-related gene expression. Thus, inhibition of RyhBs may be a potential strategy to attenuate Salmonella.
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Andersen SE, Bulman LM, Steiert B, Faris R, Weber MM. Got mutants? How advances in chlamydial genetics have furthered the study of effector proteins. Pathog Dis 2021; 79:ftaa078. [PMID: 33512479 PMCID: PMC7862739 DOI: 10.1093/femspd/ftaa078] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Accepted: 12/17/2020] [Indexed: 02/07/2023] Open
Abstract
Chlamydia trachomatis is the leading cause of infectious blindness and a sexually transmitted infection. All chlamydiae are obligate intracellular bacteria that replicate within a membrane-bound vacuole termed the inclusion. From the confines of the inclusion, the bacteria must interact with many host organelles to acquire key nutrients necessary for replication, all while promoting host cell viability and subverting host defense mechanisms. To achieve these feats, C. trachomatis delivers an arsenal of virulence factors into the eukaryotic cell via a type 3 secretion system (T3SS) that facilitates invasion, manipulation of host vesicular trafficking, subversion of host defense mechanisms and promotes bacteria egress at the conclusion of the developmental cycle. A subset of these proteins intercalate into the inclusion and are thus referred to as inclusion membrane proteins. Whereas others, referred to as conventional T3SS effectors, are released into the host cell where they localize to various eukaryotic organelles or remain in the cytosol. Here, we discuss the functions of T3SS effector proteins with a focus on how advances in chlamydial genetics have facilitated the identification and molecular characterization of these important factors.
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Affiliation(s)
- Shelby E Andersen
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Lanci M Bulman
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Brianna Steiert
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Robert Faris
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Mary M Weber
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
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Sachdeva K, Sundaramurthy V. The Interplay of Host Lysosomes and Intracellular Pathogens. Front Cell Infect Microbiol 2020; 10:595502. [PMID: 33330138 PMCID: PMC7714789 DOI: 10.3389/fcimb.2020.595502] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Accepted: 10/22/2020] [Indexed: 12/20/2022] Open
Abstract
Lysosomes are an integral part of the intracellular defense system against microbes. Lysosomal homeostasis in the host is adaptable and responds to conditions such as infection or nutritional deprivation. Pathogens such as Mycobacterium tuberculosis (Mtb) and Salmonella avoid lysosomal targeting by actively manipulating the host vesicular trafficking and reside in a vacuole altered from the default lysosomal trafficking. In this review, the mechanisms by which the respective pathogen containing vacuoles (PCVs) intersect with lysosomal trafficking pathways and maintain their distinctness are discussed. Despite such active inhibition of lysosomal targeting, emerging literature shows that different pathogens or pathogen derived products exhibit a global influence on the host lysosomal system. Pathogen mediated lysosomal enrichment promotes the trafficking of a sub-set of pathogens to lysosomes, indicating heterogeneity in the host-pathogen encounter. This review integrates recent advancements on the global lysosomal alterations upon infections and the host protective role of the lysosomes against these pathogens. The review also briefly discusses the heterogeneity in the lysosomal targeting of these pathogens and the possible mechanisms and consequences.
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Stévenin V, Chang YY, Le Toquin Y, Duchateau M, Gianetto QG, Luk CH, Salles A, Sohst V, Matondo M, Reiling N, Enninga J. Dynamic Growth and Shrinkage of the Salmonella-Containing Vacuole Determines the Intracellular Pathogen Niche. Cell Rep 2020; 29:3958-3973.e7. [PMID: 31851926 PMCID: PMC6931108 DOI: 10.1016/j.celrep.2019.11.049] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 09/23/2019] [Accepted: 11/12/2019] [Indexed: 12/21/2022] Open
Abstract
Salmonella is a human and animal pathogen that causes gastro-enteric diseases. The key to Salmonella infection is its entry into intestinal epithelial cells, where the bacterium resides within a Salmonella-containing vacuole (SCV). Salmonella entry also induces the formation of empty macropinosomes, distinct from the SCV, in the vicinity of the entering bacteria. A few minutes after its formation, the SCV increases in size through fusions with the surrounding macropinosomes. Salmonella also induces membrane tubules that emanate from the SCV and lead to SCV shrinkage. Here, we show that these antipodal events are utilized by Salmonella to either establish a vacuolar niche or to be released into the cytosol by SCV rupture. We identify the molecular machinery underlying dynamic SCV growth and shrinkage. In particular, the SNARE proteins SNAP25 and STX4 participate in SCV inflation by fusion with macropinosomes. Thus, host compartment size control emerges as a pathogen strategy for intracellular niche regulation. The early SCV simultaneously grows and shrinks through fusion and tubule formation SCV shrinkage promotes vacuolar rupture and cytosolic release IAMs are enriched in the host SNAREs SNAP25 and STX4, enabling IAM-SCV fusion Promoting SNX1-mediated tubule formation, SopB fosters SCV ruptures
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Affiliation(s)
- Virginie Stévenin
- Institut Pasteur, Dynamics of Host-Pathogen Interactions Unit, 25 Rue du Dr. Roux, Paris, France
| | - Yuen-Yan Chang
- Institut Pasteur, Dynamics of Host-Pathogen Interactions Unit, 25 Rue du Dr. Roux, Paris, France
| | - Yoann Le Toquin
- Institut Pasteur, Dynamics of Host-Pathogen Interactions Unit, 25 Rue du Dr. Roux, Paris, France
| | - Magalie Duchateau
- Institut Pasteur, Plateforme Protéomique, Unité de Spectrométrie de Masse pour la Biologie, C2RT, USR 2000 CNRS, Paris, France
| | - Quentin Giai Gianetto
- Institut Pasteur, Plateforme Protéomique, Unité de Spectrométrie de Masse pour la Biologie, C2RT, USR 2000 CNRS, Paris, France; Institut Pasteur, Bioinformatics and Biostatistics HUB, C3BI, USR CNRS 3756, Paris, France
| | - Chak Hon Luk
- Institut Pasteur, Dynamics of Host-Pathogen Interactions Unit, 25 Rue du Dr. Roux, Paris, France
| | - Audrey Salles
- Institut Pasteur, UtechS Photonic BioImaging PBI (Imagopole), Centre de Recherche et de Ressources Technologiques C2RT, Paris, France
| | - Victoria Sohst
- Research Center Borstel, Leibniz Lung Center, RG Microbial Interface Biology, Parkallee 22, 23845 Borstel, Germany
| | - Mariette Matondo
- Institut Pasteur, Plateforme Protéomique, Unité de Spectrométrie de Masse pour la Biologie, C2RT, USR 2000 CNRS, Paris, France
| | - Norbert Reiling
- Research Center Borstel, Leibniz Lung Center, RG Microbial Interface Biology, Parkallee 22, 23845 Borstel, Germany; German Center for Infection Research (DZIF), Partner Site Hamburg-Lübeck-Borstel-Riems, Borstel, Germany
| | - Jost Enninga
- Institut Pasteur, Dynamics of Host-Pathogen Interactions Unit, 25 Rue du Dr. Roux, Paris, France.
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Kehl A, Göser V, Reuter T, Liss V, Franke M, John C, Richter CP, Deiwick J, Hensel M. A trafficome-wide RNAi screen reveals deployment of early and late secretory host proteins and the entire late endo-/lysosomal vesicle fusion machinery by intracellular Salmonella. PLoS Pathog 2020; 16:e1008220. [PMID: 32658937 PMCID: PMC7377517 DOI: 10.1371/journal.ppat.1008220] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2019] [Revised: 07/23/2020] [Accepted: 05/19/2020] [Indexed: 12/17/2022] Open
Abstract
The intracellular lifestyle of Salmonella enterica is characterized by the formation of a replication-permissive membrane-bound niche, the Salmonella-containing vacuole (SCV). As a further consequence of the massive remodeling of the host cell endosomal system, intracellular Salmonella establish a unique network of various Salmonella-induced tubules (SIT). The bacterial repertoire of effector proteins required for the establishment for one type of these SIT, the Salmonella-induced filaments (SIF), is rather well-defined. However, the corresponding host cell proteins are still poorly understood. To identify host factors required for the formation of SIF, we performed a sub-genomic RNAi screen. The analyses comprised high-resolution live cell imaging to score effects on SIF induction, dynamics and morphology. The hits of our functional RNAi screen comprise: i) The late endo-/lysosomal SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) complex, consisting of STX7, STX8, VTI1B, and VAMP7 or VAMP8, which is, in conjunction with RAB7 and the homotypic fusion and protein sorting (HOPS) tethering complex, a complete vesicle fusion machinery. ii) Novel interactions with the early secretory GTPases RAB1A and RAB1B, providing a potential link to coat protein complex I (COPI) vesicles and reinforcing recently identified ties to the endoplasmic reticulum. iii) New connections to the late secretory pathway and/or the recycling endosome via the GTPases RAB3A, RAB8A, and RAB8B and the SNAREs VAMP2, VAMP3, and VAMP4. iv) An unprecedented involvement of clathrin-coated structures. The resulting set of hits allowed us to characterize completely new host factor interactions, and to strengthen observations from several previous studies. The facultative intracellular pathogen Salmonella enterica serovar Typhimurium induces the reorganization of the endosomal system of mammalian host cells. This activity is dependent on translocated effector proteins of the pathogen. The host cell factors required for endosomal remodeling are only partially known. To identify such factors for the formation and dynamics of endosomal compartments in Salmonella-infected cells, we performed a live cell imaging-based RNAi screen to investigate the role of 496 mammalian proteins involved in cellular logistics. We identified that endosomal remodeling by intracellular Salmonella is dependent on host factors in the following functional classes: i) the late endo-/lysosomal SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) complex, ii) the early secretory pathway, represented by regulator GTPases RAB1A and RAB1B, iii) the late secretory pathway and/or recycling endosomes represented by GTPases RAB3A, RAB8A, RAB8B, and the SNAREs VAMP2, VAMP3, and VAMP4, and iv) clathrin-coated structures. The identification of these new host factors provides further evidence for the complex manipulation of host cell transport functions by intracellular Salmonella and should enable detailed follow-up studies on the mechanisms involved.
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Affiliation(s)
- Alexander Kehl
- Division of Microbiology, University of Osnabrück, Osnabrück, Germany
- Division of Biophysics, University of Osnabrück, Osnabrück, Germany
- * E-mail: (AK); (MH)
| | - Vera Göser
- Division of Microbiology, University of Osnabrück, Osnabrück, Germany
| | - Tatjana Reuter
- Division of Microbiology, University of Osnabrück, Osnabrück, Germany
| | - Viktoria Liss
- Division of Microbiology, University of Osnabrück, Osnabrück, Germany
| | - Maximilian Franke
- Division of Microbiology, University of Osnabrück, Osnabrück, Germany
| | - Christopher John
- Division of Microbiology, University of Osnabrück, Osnabrück, Germany
| | | | - Jörg Deiwick
- Division of Microbiology, University of Osnabrück, Osnabrück, Germany
| | - Michael Hensel
- Division of Microbiology, University of Osnabrück, Osnabrück, Germany
- CellNanOs–Center for Cellular Nanoanalytics, Fachbereich Biologie/Chemie, Universität Osnabrück, Osnabrück, Germany
- * E-mail: (AK); (MH)
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Varela-Chavez C, Blondel A, Popoff MR. Bacterial intracellularly active toxins: Membrane localisation of the active domain. Cell Microbiol 2020; 22:e13213. [PMID: 32353188 DOI: 10.1111/cmi.13213] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 04/06/2020] [Accepted: 04/17/2020] [Indexed: 12/31/2022]
Abstract
Numerous bacterial toxins exert their activity by inactivating or modulating a specific intracellular host target. For this purpose, these toxins have developed efficient strategies to overcome the different host cell defences including specific binding to cell surface, internalisation, passage through the endosome or plasma membrane, exploiting intracellular trafficking and addressing to intracellular targets. Several intracellularly active toxins deliver an active domain into the cytosol that interacts with a target localised to the inner face of the plasma membrane. Thus, the large clostridial glucosylating toxins (LCGTs) target Rho/Ras-GTPases, certain virulence factors of Gram negative bacteria, Rho-GTPases, while Pasteurella multocida toxin (PMT) targets trimeric G-proteins. Others such as botulinum neurotoxins and tetanus neurotoxin have their substrate on synaptic vesicle membrane. LCGTs, PMT, and certain virulence factors from Vibrio sp. show a particular structure constituted of a four-helix bundle membrane (4HBM) protruding from the catalytic site that specifically binds to the membrane phospholipids and then trap the catalytic domain at the proximity of the membrane anchored substrate. Structural and functional analysis indicate that the 4HBM tip of the Clostridium sordellii lethal toxin (TcsL) from the LCGT family contain two loops forming a cavity that mediates the binding to phospholipids and more specifically to phosphatidylserine.
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Affiliation(s)
| | - Arnaud Blondel
- Unité de Bio-Informatique Structurale, Institut Pasteur, Paris, France
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Azimi T, Zamirnasta M, Sani MA, Soltan Dallal MM, Nasser A. Molecular Mechanisms of Salmonella Effector Proteins: A Comprehensive Review. Infect Drug Resist 2020; 13:11-26. [PMID: 32021316 PMCID: PMC6954085 DOI: 10.2147/idr.s230604] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 12/20/2019] [Indexed: 12/27/2022] Open
Abstract
Salmonella can be categorized into many serotypes, which are specific to known hosts or broadhosts. It makes no difference which one of the serotypes would penetrate the gastrointestinal tract because they all face similar obstacles such as mucus and microbiome. However, following their penetration, some species remain in the gastrointestinal tract; yet, others spread to another organ like gallbladder. Salmonella is required to alter the immune response to sustain its intracellular life. Changing the host response requires particular effector proteins and vehicles to translocate them. To this end, a categorized gene called Salmonella pathogenicity island (SPI) was developed; genes like Salmonella pathogenicity island encode aggressive or modulating proteins. Initially, Salmonella needs to be attached and stabilized via adhesin factor, without which no further steps can be taken. In this review, an attempt has been made to elaborate on each factor attached to the host cell or to modulating and aggressive proteins that evade immune systems. This review includes four sections: (A) attachment factors or T3SS- independent entrance, (B) effector proteins or T3SS-dependent entrance, (c) regulation of invasive genes, and (D) regulation of immune responses.
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Affiliation(s)
- Taher Azimi
- Pediatric Infections Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Students Scientific Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Maryam Zamirnasta
- Clinical Microbiology Research Center, Ilam University of Medical Science, Ilam, Iran
| | - Mahmood Alizadeh Sani
- Food Safety and Hygiene Division, Environmental health Department, School of Public Health, Tehran University of medical sciences, Tehran, Iran
- Students Research Committee, Department of Food Sciences and Technology, Faculty of Nutrition and Food Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
| | | | - Ahmad Nasser
- Clinical Microbiology Research Center, Ilam University of Medical Science, Ilam, Iran
- Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
- Department of Medical Microbiology, School of Medicine, Ilam University of Medical Science, Ilam, Iran
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Chong A, Starr T, Finn CE, Steele-Mortimer O. A role for the Salmonella Type III Secretion System 1 in bacterial adaptation to the cytosol of epithelial cells. Mol Microbiol 2019; 112:1270-1283. [PMID: 31370104 DOI: 10.1111/mmi.14361] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/29/2019] [Indexed: 12/15/2022]
Abstract
Salmonella enterica serovar Typhimurium is a facultative intracellular pathogen that invades the intestinal epithelium. Following invasion of epithelial cells, Salmonella survives and replicates within two distinct intracellular niches. While all of the bacteria are initially taken up into a membrane bound vacuole, the Salmonella-containing vacuole or SCV, a significant proportion of them promptly escape into the cytosol. Cytosolic Salmonella replicates more rapidly compared to the vacuolar population, although the reasons for this are not well understood. SipA, a multi-function effector protein, has been shown to affect intracellular replication and is secreted by cytosolic Salmonella via the invasion-associated Type III Secretion System 1 (T3SS1). Here, we have used a multipronged microscopy approach to show that SipA does not affect bacterial replication rates per se, but rather mediates intra-cytosolic survival and/or initiation of replication following bacterial egress from the SCV. Altogether, our findings reveal an important role for SipA in the early survival of cytosolic Salmonella.
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Affiliation(s)
- Audrey Chong
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | - Tregei Starr
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | - Ciaran E Finn
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | - Olivia Steele-Mortimer
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
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