51
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Röder J, Felgner P, Hensel M. Comprehensive Single Cell Analyses of the Nutritional Environment of Intracellular Salmonella enterica. Front Cell Infect Microbiol 2021; 11:624650. [PMID: 33834004 PMCID: PMC8021861 DOI: 10.3389/fcimb.2021.624650] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Accepted: 01/25/2021] [Indexed: 12/11/2022] Open
Abstract
The facultative intracellular pathogen Salmonella enterica Typhimurium (STM) resides in a specific membrane-bound compartment termed the Salmonella-containing vacuole (SCV). STM is able to obtain all nutrients required for rapid proliferation, although being separated from direct access to host cell metabolites. The formation of specific tubular membrane compartments, called Salmonella-induced filaments (SIFs) are known to provides bacterial nutrition by giving STM access to endocytosed material and enabling proliferation. Additionally, STM expresses a range of nutrient uptake system for growth in nutrient limited environments to overcome the nutrition depletion inside the host. By utilizing dual fluorescence reporters, we shed light on the nutritional environment of intracellular STM in various host cells and distinct intracellular niches. We showed that STM uses nutrients of the host cell and adapts uniquely to the different nutrient conditions. In addition, we provide further evidence for improved nutrient supply by SIF formation or presence in the cytosol of epithelial cells, and the correlation of nutrient supply to bacterial proliferation.
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Affiliation(s)
- Jennifer Röder
- Abteilung Mikrobiologie, Universität Osnabrück, Osnabrück, Germany
| | - Pascal Felgner
- Abteilung Mikrobiologie, Universität Osnabrück, Osnabrück, Germany
| | - Michael Hensel
- Abteilung Mikrobiologie, Universität Osnabrück, Osnabrück, Germany
- CellNanOs – Center of Cellular Nanoanalytics, Fachbereich Biologie/Chemie, Universität Osnabrück, Osnabrück, Germany
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52
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Type I IFNs facilitate innate immune control of the opportunistic bacteria Burkholderia cenocepacia in the macrophage cytosol. PLoS Pathog 2021; 17:e1009395. [PMID: 33684179 PMCID: PMC7971856 DOI: 10.1371/journal.ppat.1009395] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 03/18/2021] [Accepted: 02/16/2021] [Indexed: 12/20/2022] Open
Abstract
The mammalian immune system is constantly challenged by signals from both pathogenic and non-pathogenic microbes. Many of these non-pathogenic microbes have pathogenic potential if the immune system is compromised. The importance of type I interferons (IFNs) in orchestrating innate immune responses to pathogenic microbes has become clear in recent years. However, the control of opportunistic pathogens-and especially intracellular bacteria-by type I IFNs remains less appreciated. In this study, we use the opportunistic, Gram-negative bacterial pathogen Burkholderia cenocepacia (Bc) to show that type I IFNs are capable of limiting bacterial replication in macrophages, preventing illness in immunocompetent mice. Sustained type I IFN signaling through cytosolic receptors allows for increased expression of autophagy and linear ubiquitination mediators, which slows bacterial replication. Transcriptomic analyses and in vivo studies also show that LPS stimulation does not replicate the conditions of intracellular Gram-negative bacterial infection as it pertains to type I IFN stimulation or signaling. This study highlights the importance of type I IFNs in protection against opportunistic pathogens through innate immunity, without the need for damaging inflammatory responses.
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53
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Jiang L, Wang P, Song X, Zhang H, Ma S, Wang J, Li W, Lv R, Liu X, Ma S, Yan J, Zhou H, Huang D, Cheng Z, Yang C, Feng L, Wang L. Salmonella Typhimurium reprograms macrophage metabolism via T3SS effector SopE2 to promote intracellular replication and virulence. Nat Commun 2021; 12:879. [PMID: 33563986 PMCID: PMC7873081 DOI: 10.1038/s41467-021-21186-4] [Citation(s) in RCA: 60] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 01/11/2021] [Indexed: 12/14/2022] Open
Abstract
Salmonella Typhimurium establishes systemic infection by replicating in host macrophages. Here we show that macrophages infected with S. Typhimurium exhibit upregulated glycolysis and decreased serine synthesis, leading to accumulation of glycolytic intermediates. The effects on serine synthesis are mediated by bacterial protein SopE2, a type III secretion system (T3SS) effector encoded in pathogenicity island SPI-1. The changes in host metabolism promote intracellular replication of S. Typhimurium via two mechanisms: decreased glucose levels lead to upregulated bacterial uptake of 2- and 3-phosphoglycerate and phosphoenolpyruvate (carbon sources), while increased pyruvate and lactate levels induce upregulation of another pathogenicity island, SPI-2, known to encode virulence factors. Pharmacological or genetic inhibition of host glycolysis, activation of host serine synthesis, or deletion of either the bacterial transport or signal sensor systems for those host glycolytic intermediates impairs S. Typhimurium replication or virulence. Salmonella Typhimurium establishes systemic infection by replicating in host macrophages. Here, Jiang et al. show that infected macrophages exhibit upregulated glycolysis and decreased serine synthesis, leading to accumulation of glycolytic intermediates that promote intracellular replication and virulence of S. Typhimurium.
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Affiliation(s)
- Lingyan Jiang
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin, China.,TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, Tianjin, China
| | - Peisheng Wang
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin, China.,TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, Tianjin, China
| | - Xiaorui Song
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin, China.,TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, Tianjin, China
| | - Huan Zhang
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin, China.,TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, Tianjin, China
| | - Shuangshuang Ma
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin, China.,TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, Tianjin, China
| | - Jingting Wang
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin, China.,TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, Tianjin, China
| | - Wanwu Li
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin, China.,TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, Tianjin, China
| | - Runxia Lv
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin, China.,TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, Tianjin, China
| | - Xiaoqian Liu
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin, China.,TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, Tianjin, China
| | - Shuai Ma
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin, China.,TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, Tianjin, China
| | - Jiaqi Yan
- College of Life Sciences, Nankai University, Tianjin, China
| | - Haiyan Zhou
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Di Huang
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin, China.,TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, Tianjin, China
| | - Zhihui Cheng
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin, China.,College of Life Sciences, Nankai University, Tianjin, China
| | - Chen Yang
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Lu Feng
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin, China. .,TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, Tianjin, China.
| | - Lei Wang
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin, China. .,TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, Tianjin, China. .,The Institute of Translational Medicine Research, Tianjin Union Medical Center, Nankai University Affiliated Hospital, Nankai University, Tianjin, China.
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54
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Schulte M, Olschewski K, Hensel M. Fluorescent protein-based reporters reveal stress response of intracellular Salmonella enterica at level of single bacterial cells. Cell Microbiol 2020; 23:e13293. [PMID: 33222378 DOI: 10.1111/cmi.13293] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 11/17/2020] [Accepted: 11/18/2020] [Indexed: 12/17/2022]
Abstract
Intracellular bacteria such as Salmonella enterica are confronted with a broad array of defence mechanisms of their mammalian host cells. The ability to sense host cell-imposed damages, and to mount efficient stress responses are crucial for survival and proliferation of intracellular pathogens. The various combinations of host defence mechanisms acting on intracellular bacteria and their individual response also explain the occurrence of distinct subpopulations of intracellular S. enterica such as dormant or persisting, slowly or rapidly replicating cells. Here we describe a set of fluorescence protein (FP)-based reporter strains that were used to monitor the expression of cytoplasmic or periplasmic stress response systems of single bacterial cells. This is mediated by a fast-maturing FP as reporter for induction of stress response genes. We evaluated slower maturing FPs for a second function, that is, the analysis of the status of intracellular proliferation of pathogens. The combination of two FPs allows, at level of single bacterial cells, the interrogation of stress response and intracellular proliferation. Application of these reporters to S. enterica allowed us to detect and quantify distinct intracellular subpopulations with different levels of stress response and proliferation.
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Affiliation(s)
- Marc Schulte
- Abteilung Mikrobiologie, CellNanOs - Center of Cellular Nanoanalytics Osnabrück, Universität Osnabrück, Osnabrück, Germany
| | - Katharina Olschewski
- Abteilung Mikrobiologie, CellNanOs - Center of Cellular Nanoanalytics Osnabrück, Universität Osnabrück, Osnabrück, Germany
| | - Michael Hensel
- Abteilung Mikrobiologie, CellNanOs - Center of Cellular Nanoanalytics Osnabrück, Universität Osnabrück, Osnabrück, Germany
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55
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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: 6.3] [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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56
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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: 41] [Impact Index Per Article: 10.3] [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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57
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Self-Labeling Enzyme Tags for Translocation Analyses of Salmonella Effector Proteins. Methods Mol Biol 2020. [PMID: 32894488 DOI: 10.1007/978-1-0716-0791-6_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Salmonella enterica is an invasive, facultative intracellular pathogen with a highly sophisticated intracellular lifestyle. Invasion and intracellular proliferation are dependent on the translocation of effector proteins by two distinct type III secretion systems (T3SS) into the host cell. To unravel host-pathogen interactions, dedicated imaging techniques visualizing Salmonella effector proteins during the infection are essential. Here we describe a new approach utilizing self-labeling enzyme (SLE) tags as a universal labeling tool for tracing effector proteins. This method is able to resolve the temporal and spatial dynamics of effector proteins in living cells. The method is applicable to conventional confocal fluorescence microscopy, but also to tracking and localization microscopy (TALM), and super-resolution microscopy (SRM) of single molecules, allowing the visualization of effector proteins beyond the optical diffraction limit.
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58
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Kehl A, Noster J, Hensel M. Eat in or Take out? Metabolism of Intracellular Salmonella enterica. Trends Microbiol 2020; 28:644-654. [DOI: 10.1016/j.tim.2020.03.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2019] [Revised: 03/15/2020] [Accepted: 03/25/2020] [Indexed: 02/07/2023]
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59
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Knuff-Janzen K, Tupin A, Yurist-Doutsch S, Rowland JL, Finlay BB. Multiple Salmonella-pathogenicity island 2 effectors are required to facilitate bacterial establishment of its intracellular niche and virulence. PLoS One 2020; 15:e0235020. [PMID: 32584855 PMCID: PMC7316343 DOI: 10.1371/journal.pone.0235020] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Accepted: 06/05/2020] [Indexed: 12/31/2022] Open
Abstract
The pathogenesis of Salmonella Typhimurium depends on the
bacterium’s ability to survive and replicate within host cells. The formation
and maintenance of a unique membrane-bound compartment, termed the
Salmonella-containing vacuole (SCV), is essential for
S. Typhimurium pathogenesis. SCV-bound S.
Typhimurium induces formation of filamentous tubules that radiate outwards from
the SCV, termed Salmonella-induced filaments (SIFs). SIF
formation is concomitant with the onset of replication within host epithelial
cells. SIF biogenesis, formation and maintenance of the SCV, and the
intracellular positioning of the SCV within the host cell requires translocation
of bacterial proteins (effectors) into the host cell. Effectors secreted by the
type III secretion system encoded on Salmonella pathogenicity
island 2 (T3SS2) function to interfere with host cellular processes and promote
both intracellular survival and replication of S. Typhimurium.
Seven T3SS2-secreted effectors, SifA, SopD2, PipB2, SteA, SseJ, SseF, and SseG
have previously been implicated to play complementary, redundant, and/or
antagonistic roles with respect to SIF biogenesis, intracellular positioning of
the SCV, and SCV membrane dynamics modulation during infection. We undertook a
systematic study to delineate the contribution of each effector to these
processes by (i) deleting all seven of these effectors in a single
S. Typhimurium strain; and (ii) deleting combinations of
multiple effectors based on putative effector function. Using this deletion
mutant library, we show that each of SIF biogenesis, intracellular SCV
localization, intramacrophage replication, colonization, and virulence depends
on the activities of multiple effectors. Together, our data demonstrates the
complex interplay between these seven effectors and highlights the necessity to
study T3SS2-secreted effectors as groups, rather than studies of individual
effectors.
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Affiliation(s)
- Katelyn Knuff-Janzen
- Michael Smith Laboratories, University of British Columbia, Vancouver,
British Columbia, Canada
- Department of Microbiology & Immunology, University of British
Columbia, Vancouver, British Columbia, Canada
| | - Audrey Tupin
- Michael Smith Laboratories, University of British Columbia, Vancouver,
British Columbia, Canada
- Department of Microbiology & Immunology, University of British
Columbia, Vancouver, British Columbia, Canada
| | - Sophie Yurist-Doutsch
- Michael Smith Laboratories, University of British Columbia, Vancouver,
British Columbia, Canada
- Department of Microbiology & Immunology, University of British
Columbia, Vancouver, British Columbia, Canada
| | - Jennifer L. Rowland
- Michael Smith Laboratories, University of British Columbia, Vancouver,
British Columbia, Canada
- Department of Microbiology & Immunology, University of British
Columbia, Vancouver, British Columbia, Canada
| | - B. Brett Finlay
- Michael Smith Laboratories, University of British Columbia, Vancouver,
British Columbia, Canada
- Department of Microbiology & Immunology, University of British
Columbia, Vancouver, British Columbia, Canada
- Department of Biochemistry and Molecular Biology, University of British
Columbia, Vancouver, British Columbia, Canada
- * E-mail:
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60
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Galeev A, Suwandi A, Bakker H, Oktiviyari A, Routier FH, Krone L, Hensel M, Grassl GA. Proteoglycan-Dependent Endo-Lysosomal Fusion Affects Intracellular Survival of Salmonella Typhimurium in Epithelial Cells. Front Immunol 2020; 11:731. [PMID: 32411142 PMCID: PMC7201003 DOI: 10.3389/fimmu.2020.00731] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 03/31/2020] [Indexed: 11/28/2022] Open
Abstract
Proteoglycans (PGs) are glycoconjugates which are predominately expressed on cell surfaces and consist of glycosaminoglycans (GAGs) linked to a core protein. An initial step of GAGs assembly is governed by the β-D-xylosyltransferase enzymes encoded in mammals by the XylT1/XylT2 genes. PGs are essential for the interaction of a cell with other cells as well as with the extracellular matrix. A number of studies highlighted a role of PGs in bacterial adhesion, invasion, and immune response. In this work, we investigated a role of PGs in Salmonella enterica serovar Typhimurium (S. Typhimurium) infection of epithelial cells. Gentamicin protection and chloroquine resistance assays were applied to assess invasion and replication of S. Typhimurium in wild-type and xylosyltransferase-deficient (ΔXylT2) Chinese hamster ovary (CHO) cells lacking PGs. We found that S. Typhimurium adheres to and invades CHO WT and CHO ΔXylT2 cells at comparable levels. However, 24 h after infection, proteoglycan-deficient CHO ΔXylT2 cells are significantly less colonized by S. Typhimurium compared to CHO WT cells. This proteoglycan-dependent phenotype could be rescued by addition of PGs to the cell culture medium, as well as by complementation of the XylT2 gene. Chloroquine resistance assay and immunostaining revealed that in the absence of PGs, significantly less bacteria are associated with Salmonella-containing vacuoles (SCVs) due to a re-distribution of endocytosed gentamicin. Inhibition of endo-lysosomal fusion by a specific inhibitor of phosphatidylinositol phosphate kinase PIKfyve significantly increased S. Typhimurium burden in CHO ΔXylT2 cells demonstrating an important role of PGs for PIKfyve dependent vesicle fusion which is modulated by Salmonella to establish infection. Overall, our results demonstrate that PGs influence survival of intracellular Salmonella in epithelial cells via modulation of PIKfyve-dependent endo-lysosomal fusion.
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Affiliation(s)
- Alibek Galeev
- Institute of Medical Microbiology and Hospital Epidemiology, Hannover Medical School and German Center for Infection Research (DZIF), Hanover, Germany
| | - Abdulhadi Suwandi
- Institute of Medical Microbiology and Hospital Epidemiology, Hannover Medical School and German Center for Infection Research (DZIF), Hanover, Germany
| | - Hans Bakker
- Institute of Clinical Biochemistry, Hannover Medical School, Hanover, Germany
| | - Ade Oktiviyari
- Institute of Medical Microbiology and Hospital Epidemiology, Hannover Medical School and German Center for Infection Research (DZIF), Hanover, Germany
| | - Françoise H Routier
- Institute of Clinical Biochemistry, Hannover Medical School, Hanover, Germany
| | - Lena Krone
- Division of Microbiology, University of Osnabrück, Osnabrück, Germany
| | - Michael Hensel
- Division of Microbiology, University of Osnabrück, Osnabrück, Germany
| | - Guntram A Grassl
- Institute of Medical Microbiology and Hospital Epidemiology, Hannover Medical School and German Center for Infection Research (DZIF), Hanover, Germany
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61
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Alberdi L, Vergnes A, Manneville JB, Tembo DL, Fang Z, Zhao Y, Schroeder N, Dumont A, Lagier M, Bassereau P, Redondo-Morata L, Gorvel JP, Méresse S. Regulation of kinesin-1 activity by the Salmonella enterica effectors PipB2 and SifA. J Cell Sci 2020; 133:133/9/jcs239863. [PMID: 32409568 DOI: 10.1242/jcs.239863] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 03/13/2020] [Indexed: 11/20/2022] Open
Abstract
Salmonella enterica is an intracellular bacterial pathogen. The formation of its replication niche, which is composed of a vacuole associated with a network of membrane tubules, depends on the secretion of a set of bacterial effector proteins whose activities deeply modify the functions of the eukaryotic host cell. By recruiting and regulating the activity of the kinesin-1 molecular motor, Salmonella effectors PipB2 and SifA play an essential role in the formation of the bacterial compartments. In particular, they allow the formation of tubules from the vacuole and their extension along the microtubule cytoskeleton, and thus promote membrane exchanges and nutrient supply. We have developed in vitro and in cellulo assays to better understand the specific role played by these two effectors in the recruitment and regulation of kinesin-1. Our results reveal a specific interaction between the two effectors and indicate that, contrary to what studies on infected cells suggested, interaction with PipB2 is sufficient to relieve the autoinhibition of kinesin-1. Finally, they suggest the involvement of other Salmonella effectors in the control of the activity of this molecular motor.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
| | | | - Jean-Baptiste Manneville
- Institut Curie, PSL Research University, CNRS, UMR 144, 26 rue d'Ulm, F-75005, Paris, France.,Sorbonne Université, UPMC University Paris 06, CNRS, UMR 144, 26 rue d'Ulm, F-75005, Paris, France
| | | | - Ziyan Fang
- Aix-Marseille Université, CNRS, INSERM, CIML, Marseille, France
| | - Yaya Zhao
- Aix-Marseille Université, CNRS, INSERM, CIML, Marseille, France
| | - Nina Schroeder
- Aix-Marseille Université, CNRS, INSERM, CIML, Marseille, France
| | - Audrey Dumont
- Aix-Marseille Université, CNRS, INSERM, CIML, Marseille, France
| | - Margaux Lagier
- Aix-Marseille Université, CNRS, INSERM, CIML, Marseille, France
| | - Patricia Bassereau
- Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, CNRS UMR168, 75005 Paris, France.,Sorbonne Université, 1 Place Jussieu, 75005 Paris, France
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62
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Ammanathan V, Vats S, Abraham IM, Manjithaya R. Xenophagy in cancer. Semin Cancer Biol 2020; 66:163-170. [PMID: 32126260 DOI: 10.1016/j.semcancer.2020.02.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 02/17/2020] [Indexed: 12/24/2022]
Abstract
Macroautophagy (herein autophagy) is an intracellular pathway in which cytoplasmic components are captured by double-membrane vesicles (autophagosomes) that eventually fuse with lysosomes to degrade the cargo. Basal levels of autophagy in all eukaryotic cells maintain cellular homeostasis and under conditions of stress, organelles and proteins not essential for survival are degraded. Apart from these functions, cargoes like aggregated proteins, damaged organelles and intracellular pathogens, which are otherwise harmful to cells, are also selectively captured by autophagy and are destined for degradation. In terms of infectious diseases, pathogens are cleared by a specific form of autophagy known as xenophagy. This lysosomal mediated degradation of pathogens also increases the antigen presentation of cells thereby inducing a further immune response. The process of xenophagy provides a broad spectrum of defense mechanism to capture bacterial, viral and protozoan pathogens. However, pathogens have developed ingenious mechanisms to modulate xenophagy to enhance their intracellular survival. Meanwhile, certain pathogens also induce deleterious effects such as chronic inflammation and overexpression of oncogenes in the host system. This over time can increase the susceptibility of the host for tumorigenesis. Hence targeting tumor through anti-microbial mechanisms like xenophagy could be a novel strategy for combinatorial anti-cancer therapy. The recent developments in understanding the role of xenophagy in combating cancer causing pathogens will be discussed in this review.
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Affiliation(s)
- Veena Ammanathan
- Jawaharlal Nehru Centre for Advanced Scientific Research, 560064, Bangalore, India
| | - Somya Vats
- Jawaharlal Nehru Centre for Advanced Scientific Research, 560064, Bangalore, India
| | - Irine Maria Abraham
- Jawaharlal Nehru Centre for Advanced Scientific Research, 560064, Bangalore, India
| | - Ravi Manjithaya
- Jawaharlal Nehru Centre for Advanced Scientific Research, 560064, Bangalore, India
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63
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Göser V, Kehl A, Röder J, Hensel M. Role of the ESCRT‐III complex in controlling integrity of the
Salmonella
‐containing vacuole. Cell Microbiol 2020; 22:e13176. [DOI: 10.1111/cmi.13176] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 12/27/2019] [Accepted: 01/20/2020] [Indexed: 12/21/2022]
Affiliation(s)
- Vera Göser
- Abt. MikrobiologieFachbereich Biologie/Chemie, Universität Osnabrück Osnabrück Germany
| | - Alexander Kehl
- Abt. MikrobiologieFachbereich Biologie/Chemie, Universität Osnabrück Osnabrück Germany
- Institut für HygieneUniversität Münster Münster Germany
- CellNanOs, Center for Cellular NanoanalyticsFachbereich Biologie/Chemie, Universität Osnabrück Osnabrück Germany
| | - Jennifer Röder
- Abt. MikrobiologieFachbereich Biologie/Chemie, Universität Osnabrück Osnabrück Germany
| | - Michael Hensel
- Abt. MikrobiologieFachbereich Biologie/Chemie, Universität Osnabrück Osnabrück Germany
- CellNanOs, Center for Cellular NanoanalyticsFachbereich Biologie/Chemie, Universität Osnabrück Osnabrück Germany
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64
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Jiang L, Wang P, Li X, Lv R, Wang L, Yang B, Huang D, Feng L, Liu B. PagR mediates the precise regulation of
Salmonella
pathogenicity island 2 gene expression in response to magnesium and phosphate signals in
Salmonella
Typhimurium. Cell Microbiol 2019; 22:e13125. [DOI: 10.1111/cmi.13125] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 09/25/2019] [Accepted: 09/26/2019] [Indexed: 01/04/2023]
Affiliation(s)
- Lingyan Jiang
- TEDA Institute of Biological Sciences and BiotechnologyNankai University Tianjin China
- The Key Laboratory of Molecular Microbiology and TechnologyMinistry of Education Tianjin China
- Tianjin Key Laboratory of Microbial Functional GenomicsNankai University Tianjin China
| | - Peisheng Wang
- TEDA Institute of Biological Sciences and BiotechnologyNankai University Tianjin China
- The Key Laboratory of Molecular Microbiology and TechnologyMinistry of Education Tianjin China
| | - Xiaomin Li
- TEDA Institute of Biological Sciences and BiotechnologyNankai University Tianjin China
- The Key Laboratory of Molecular Microbiology and TechnologyMinistry of Education Tianjin China
| | - Runxia Lv
- TEDA Institute of Biological Sciences and BiotechnologyNankai University Tianjin China
- The Key Laboratory of Molecular Microbiology and TechnologyMinistry of Education Tianjin China
| | - Lin Wang
- Inspection and Quarantine Technical CenterBeijing Entry‐Exit Inspection and Quarantine Bureau Beijing China
| | - Bin Yang
- TEDA Institute of Biological Sciences and BiotechnologyNankai University Tianjin China
- The Key Laboratory of Molecular Microbiology and TechnologyMinistry of Education Tianjin China
- Tianjin Key Laboratory of Microbial Functional GenomicsNankai University Tianjin China
| | - Di Huang
- TEDA Institute of Biological Sciences and BiotechnologyNankai University Tianjin China
- The Key Laboratory of Molecular Microbiology and TechnologyMinistry of Education Tianjin China
- Tianjin Key Laboratory of Microbial Functional GenomicsNankai University Tianjin China
| | - Lu Feng
- TEDA Institute of Biological Sciences and BiotechnologyNankai University Tianjin China
- The Key Laboratory of Molecular Microbiology and TechnologyMinistry of Education Tianjin China
- Tianjin Key Laboratory of Microbial Functional GenomicsNankai University Tianjin China
| | - Bin Liu
- TEDA Institute of Biological Sciences and BiotechnologyNankai University Tianjin China
- The Key Laboratory of Molecular Microbiology and TechnologyMinistry of Education Tianjin China
- Tianjin Key Laboratory of Microbial Functional GenomicsNankai University Tianjin China
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65
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BioID screen of Salmonella type 3 secreted effectors reveals host factors involved in vacuole positioning and stability during infection. Nat Microbiol 2019; 4:2511-2522. [PMID: 31611645 DOI: 10.1038/s41564-019-0580-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 09/09/2019] [Indexed: 12/17/2022]
Abstract
Many bacterial pathogens express virulence proteins that are translocated into host cells (herein referred to as effectors), where they can interact with target proteins to manipulate host cell processes. These effector-host protein interactions are often dynamic and transient in nature, making them difficult to identify using traditional interaction-based methods. Here, we performed a systematic comparison between proximity-dependent biotin labelling (BioID) and immunoprecipitation coupled with mass spectrometry to investigate a series of Salmonella type 3 secreted effectors that manipulate host intracellular trafficking (SifA, PipB2, SseF, SseG and SopD2). Using BioID, we identified 632 candidate interactions with 381 unique human proteins, collectively enriched for roles in vesicular trafficking, cytoskeleton components and transport activities. From the subset of proteins exclusively identified by BioID, we report that SifA interacts with BLOC-2, a protein complex that regulates dynein motor activity. We demonstrate that the BLOC-2 complex is necessary for SifA-mediated positioning of Salmonella-containing vacuoles, and affects stability of the vacuoles during infection. Our study provides insight into the coordinated activities of Salmonella type 3 secreted effectors and demonstrates the utility of BioID as a powerful, complementary tool to characterize effector-host protein interactions.
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66
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Yang CY, Hsu CY, Fang CS, Shiau CW, Chen CS, Chiu HC. Loxapine, an antipsychotic drug, suppresses intracellular multiple-antibiotic-resistant Salmonella enterica serovar Typhimurium in macrophages. JOURNAL OF MICROBIOLOGY, IMMUNOLOGY, AND INFECTION = WEI MIAN YU GAN RAN ZA ZHI 2019; 52:638-647. [DOI: 10.1016/j.jmii.2019.05.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2018] [Revised: 03/11/2019] [Accepted: 05/29/2019] [Indexed: 11/28/2022]
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67
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Wemyss MA, Pearson JS. Host Cell Death Responses to Non-typhoidal Salmonella Infection. Front Immunol 2019; 10:1758. [PMID: 31402916 PMCID: PMC6676415 DOI: 10.3389/fimmu.2019.01758] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 07/11/2019] [Indexed: 12/20/2022] Open
Abstract
Salmonella enterica subsp. enterica serovar Typhimurium (S. Typhimurium) is a Gram-negative bacterium with a broad host range that causes non-typhoidal salmonellosis in humans. S. Typhimurium infects epithelial cells and macrophages in the small intestine where it replicates in a specialized intracellular niche called the Salmonella-containing vacuole (SCV) and promotes inflammation of the mucosa to induce typically self-limiting gastroenteritis. Virulence and spread of the bacterium is determined in part by the host individual's ability to limit the infection through innate immune responses at the gastrointestinal mucosa, including programmed cell death. S. Typhimurium however, has evolved a myriad of mechanisms to counteract or exploit host responses through the use of Type III Secretion Systems (T3SS), which allow the translocation of virulence (effector) proteins into the host cell for the benefit of optimal bacterial replication and dissemination. T3SS effectors have been found to interact with apoptotic, necroptotic, and pyroptotic cell death cascades, interfering with both efficient clearance of the bacteria and the recruitment of neutrophils or dendritic cells to the area of infection. The interplay of host inflammation, programmed cell death responses, and bacterial defenses in the context of non-typhoidal Salmonella (NTS) infection is a continuing area of interest within the field, and as such has been reviewed here.
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Affiliation(s)
- Madeleine A Wemyss
- Department of Molecular and Translational Research, Monash University, Clayton, VIC, Australia.,Department of Microbiology, Monash University, Clayton, VIC, Australia
| | - Jaclyn S Pearson
- Department of Molecular and Translational Research, Monash University, Clayton, VIC, Australia.,Department of Microbiology, Monash University, Clayton, VIC, Australia
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68
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Noster J, Chao TC, Sander N, Schulte M, Reuter T, Hansmeier N, Hensel M. Proteomics of intracellular Salmonella enterica reveals roles of Salmonella pathogenicity island 2 in metabolism and antioxidant defense. PLoS Pathog 2019; 15:e1007741. [PMID: 31009521 PMCID: PMC6497321 DOI: 10.1371/journal.ppat.1007741] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Revised: 05/02/2019] [Accepted: 03/28/2019] [Indexed: 11/18/2022] Open
Abstract
Intracellular Salmonella enterica serovar Typhimurium (STM) deploy the Salmonella Pathogenicity Island 2-encoded type III secretion system (SPI2-T3SS) for the massive remodeling of the endosomal system for host cells. This activity results in formation of an extensive interconnected tubular network of Salmonella-induced filaments (SIFs) connected to the Salmonella-containing vacuole (SCV). Such network is absent in cells infected with SPI2-T3SS-deficient mutant strains such as ΔssaV. A tubular network with reduced dimensions is formed if SPI2-T3SS effector protein SseF is absent. Previous single cell live microscopy-based analyses revealed that intracellular proliferation of STM is directly correlated to the ability to transform the host cell endosomal system into a complex tubular network. This network may also abrogate host defense mechanisms such as delivery of antimicrobial effectors to the SCV. To test the role of SIFs in STM patho-metabolism, we performed quantitative comparative proteomics of STM recovered from infected murine macrophages. We infected RAW264.7 cells with STM wild type (WT), ΔsseF or ΔssaV strains, recovered bacteria 12 h after infection and determined proteome compositions. Increased numbers of proteins characteristic for nutritional starvation were detected in STM ΔsseF and ΔssaV compared to WT. In addition, STM ΔssaV, but not ΔsseF showed signatures of increased exposure to stress by antimicrobial defenses, in particular reactive oxygen species, of the host cells. The proteomics analyses presented here support and extend the role of SIFs for the intracellular lifestyle of STM. We conclude that efficient manipulation of the host cell endosomal system by effector proteins of the SPI2-T3SS contributes to nutrition, as well as to resistance against antimicrobial host defense mechanisms. The facultative intracellular bacterium Salmonella enterica has evolved sophisticated mechanisms to adapt to life inside a pathogen-containing vacuole in mammalian host cells. Intracellular Salmonella manipulate the host cell endosomal system resulting in formation of a complex network of tubular vesicles, termed Salmonella-induced filaments (SIFs). We applied quantitative proteomics to intracellular Salmonella in murine macrophages and compared the wild-type strain to mutant strains with aberrant SIF architecture, or no capacity for induction of SIF. We determined that those mutant strains contain higher amounts of transporters for nutrient uptake, and lower amounts of proteins for central carbon metabolism. These observations indicate response to nutrient restriction in absence of fully established SIF. In addition, the mutant strain unable to induce SIF formation showed increased amounts of proteins required for response to antimicrobial factors of the host cells. These data show that the massive remodeling of the endosomal system of host cells by intracellular Salmonella serves to essential needs, i.e. to enable access to nutrients for efficient proliferation of the pathogen, and to withstand hostile conditions within the pathogen-containing vacuole.
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Affiliation(s)
- Janina Noster
- Abt. Mikrobiologie, Universität Osnabrück, Osnabrück, Germany
| | - Tzu-Chiao Chao
- Institute of Environmental Change & Society, University of Regina, Regina, Canada
| | - Nathalie Sander
- Abt. Mikrobiologie, Universität Osnabrück, Osnabrück, Germany
| | - Marc Schulte
- Abt. Mikrobiologie, Universität Osnabrück, Osnabrück, Germany
| | - Tatjana Reuter
- Abt. Mikrobiologie, Universität Osnabrück, Osnabrück, Germany
| | - Nicole Hansmeier
- Abt. Mikrobiologie, Universität Osnabrück, Osnabrück, Germany.,Institute of Environmental Change & Society, University of Regina, Regina, Canada
| | - Michael Hensel
- Abt. Mikrobiologie, Universität Osnabrück, Osnabrück, Germany
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69
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LoiA directly represses lon gene expression to activate the expression of Salmonella pathogenicity island-1 genes. Res Microbiol 2019; 170:131-137. [DOI: 10.1016/j.resmic.2019.01.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 01/02/2019] [Accepted: 01/08/2019] [Indexed: 12/23/2022]
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70
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The Role of the Host in Driving Phenotypic Heterogeneity in Salmonella. Trends Microbiol 2019; 27:508-523. [PMID: 30755344 DOI: 10.1016/j.tim.2019.01.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 12/21/2018] [Accepted: 01/18/2019] [Indexed: 02/07/2023]
Abstract
The complex infection environment within hosts exerts unique stresses across tissues and cell types, selecting for phenotypic heterogeneity in bacterial populations. Pathogens maintain variability during infection as a strategy to cope with fluctuating host immune conditions, leading to diversification of virulence phenotypes. Recent improvements in single-cell analyses have revealed that distinct bacterial subpopulations contribute unique colonization and growth strategies across infection sites. We discuss several examples of host-driven phenotypic heterogeneity in Salmonella populations throughout the course of infection, highlighting how variation in gene expression, growth rate, immune evasion, and metabolic activity contribute to overall bacterial success at the population level. We additionally focus our discussion on the implications of diversity within bacterial communities for antimicrobial efficacy.
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71
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Moest T, Zhao W, Zhao Y, Schüssler JM, Yan W, Gorvel JP, Méresse S. Contribution of bacterial effectors and host proteins to the composition and function of Salmonella-induced tubules. Cell Microbiol 2018; 20:e12951. [PMID: 30212607 DOI: 10.1111/cmi.12951] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 08/31/2018] [Accepted: 09/04/2018] [Indexed: 12/17/2023]
Abstract
Cells infected with Salmonella are characterised by the appearance of membrane tubular structures that stretch from the bacterial vacuole. The formation of these tubules requires the translocation of Salmonella effector proteins within the infected cell. Different types of Salmonella-induced tubules with varying host protein compositions have been identified. This variability probably reflects the ability of these tubules to interact with different host compartments. Membrane tubules decorated with effector proteins but essentially devoid of host proteins and named LAMP1-negative (LNT) were observed. LNTs wrap around LAMP1-positive vesicles and may promote recruitment of lysosomal glycoproteins to bacterial vacuole and the formation of a replication niche. We conducted a biochemical and functional characterisation of LNTs. We show that the effector proteins SseF and SseG are necessary for their formation. The absence of these tubules is associated with decreased recruitment of LAMP1 to SCVs, decreased intracellular replication of Salmonella, and decreased virulence in mice. We found that the process leading to the recruitment of lysosomal glycoproteins to tubules involves the C-terminal domain of the effector protein SifA and the GTPase Arl8b. Overall, these data suggest that Salmonella-induced tubules promote the establishment of the replication niche by promoting recruitment of host proteins to the bacterial vacuole.
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Affiliation(s)
- Thomas Moest
- Aix Marseille Univ, CNRS, INSERM, CIML, Marseille, France
| | - Weidong Zhao
- Aix Marseille Univ, CNRS, INSERM, CIML, Marseille, France
| | - Yaya Zhao
- Aix Marseille Univ, CNRS, INSERM, CIML, Marseille, France
| | | | - Wen Yan
- Aix Marseille Univ, CNRS, INSERM, CIML, Marseille, France
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72
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Tuli A, Sharma M. How to do business with lysosomes: Salmonella leads the way. Curr Opin Microbiol 2018; 47:1-7. [PMID: 30391777 DOI: 10.1016/j.mib.2018.10.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Revised: 10/02/2018] [Accepted: 10/05/2018] [Indexed: 11/19/2022]
Abstract
Pathogens have devised various strategies to alter the host endomembrane system towards building their replicative niche. This is aptly illustrated by Salmonella Typhimurium, whereby it remodels the host endolysosomal system to form a unique niche, also known as Salmonella-containing vacuole (SCV). Decades of research using in vitro cell-based infection studies have revealed intricate details of how Salmonella effectors target endocytic trafficking machinery of the host cell to acquire membrane and nutrients for bacterial replication. Unexpectedly, Salmonella requires host factors involved in endosome-lysosome fusion for its intravacuolar replication. Understanding how Salmonella obtains selective content from lysosomes, that is nutrients, but not active hydrolases, needs further exploration. Recent studies have described heterogeneity in the composition and pH of lysosomes, which will be highly relevant to explore, not only in the context of Salmonella infection, but also for other intracellular pathogens that interact with the endolysosomal pathway.
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Affiliation(s)
- Amit Tuli
- Division of Cell Biology and Immunology, CSIR-Institute of Microbial Technology (IMTECH), Chandigarh, India.
| | - Mahak Sharma
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER)-Mohali, Punjab, India.
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73
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Hefele M, Stolzer I, Ruder B, He GW, Mahapatro M, Wirtz S, Neurath MF, Günther C. Intestinal epithelial Caspase-8 signaling is essential to prevent necroptosis during Salmonella Typhimurium induced enteritis. Mucosal Immunol 2018; 11:1191-1202. [PMID: 29520026 DOI: 10.1038/s41385-018-0011-x] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 01/03/2018] [Accepted: 01/14/2018] [Indexed: 02/04/2023]
Abstract
Although induction of host cell death is a pivotal step during bacteria-induced gastroenteritis, the molecular regulation remains to be fully characterized. To expand our knowledge, we investigated the role of the central cell death regulator Caspase-8 in response to Salmonella Typhimurium. Here, we uncovered that intestinal salmonellosis was associated with strong upregulation of members of the host cell death machinery in intestinal epithelial cells (IECs) as an early event, suggesting that elimination of infected IECs represents a host defense strategy. Indeed, Casp8∆IEC mice displayed severe tissue damage and high lethality after infection. Additional deletion of Ripk3 or Mlkl rescued epithelial cell death and lethality of Casp8∆IEC mice, demonstrating the crucial role of Caspase-8 as a negative regulator of necroptosis. While Casp8∆IECTnfr1-/- mice showed improved survival after infection, tissue destruction was similar to Casp8∆IEC mice, indicating that necroptosis partially depends on TNF-α signaling. Although there was no impairment in antimicrobial peptide secretion during the early phase of infection, functional Caspase-8 seems to be required to control pathogen colonization. Collectively, these results demonstrate that Caspase-8 is essential to prevent Salmonella Typhimurium induced enteritis and to ensure host survival by two different mechanisms: maintenance of intestinal barrier function and restriction of pathogen colonization.
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Affiliation(s)
- Manuela Hefele
- Department of Medicine 1, University of Erlangen-Nuremberg, Erlangen, Germany
| | - Iris Stolzer
- Department of Medicine 1, University of Erlangen-Nuremberg, Erlangen, Germany
| | - Barbara Ruder
- Department of Medicine 1, University of Erlangen-Nuremberg, Erlangen, Germany
| | - Gui-Wei He
- Department of Medicine 1, University of Erlangen-Nuremberg, Erlangen, Germany
| | - Mousumi Mahapatro
- Department of Medicine 1, University of Erlangen-Nuremberg, Erlangen, Germany
| | - Stefan Wirtz
- Department of Medicine 1, University of Erlangen-Nuremberg, Erlangen, Germany
| | - Markus F Neurath
- Department of Medicine 1, University of Erlangen-Nuremberg, Erlangen, Germany
| | - Claudia Günther
- Department of Medicine 1, University of Erlangen-Nuremberg, Erlangen, Germany.
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74
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Thompson A, Fulde M, Tedin K. The metabolic pathways utilized by Salmonella Typhimurium during infection of host cells. ENVIRONMENTAL MICROBIOLOGY REPORTS 2018; 10:140-154. [PMID: 29411544 DOI: 10.1111/1758-2229.12628] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 01/29/2018] [Accepted: 01/31/2018] [Indexed: 06/08/2023]
Abstract
Only relatively recently has research on the metabolism of intracellular bacterial pathogens within their host cells begun to appear in the published literature. This reflects in part the experimental difficulties encountered in separating host metabolic processes from those of the resident pathogen. One of the most genetically tractable and thoroughly studied intracellular bacterial pathogens, Salmonella enterica serovar Typhimurium (S. Typhimurium), has been at the forefront of metabolic studies within eukaryotic host cells. In this review, we offer a synthesis of what has been discovered to date regarding the metabolic adaptation of S. Typhimurium to survival and growth within the infected host. We discuss many studies in the context of techniques used, types of host cells, how host metabolites contribute to intracellular survival and proliferation of the pathogen and how bacterial metabolism affects the virulence and persistence of the pathogen.
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Affiliation(s)
- Arthur Thompson
- Institute for Food Research, Norwich Research Park, Norwich NR4 7UA, UK
| | - Marcus Fulde
- Centre for Infection Medicine, Institute of Microbiology and Epizootics, Freie Universität Berlin, 14163 Berlin, Germany
| | - Karsten Tedin
- Centre for Infection Medicine, Institute of Microbiology and Epizootics, Freie Universität Berlin, 14163 Berlin, Germany
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75
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Fredlund J, Santos JC, Stévenin V, Weiner A, Latour-Lambert P, Rechav K, Mallet A, Krijnse-Locker J, Elbaum M, Enninga J. The entry ofSalmonellain a distinct tight compartment revealed at high temporal and ultrastructural resolution. Cell Microbiol 2018; 20. [DOI: 10.1111/cmi.12816] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 12/08/2017] [Accepted: 12/11/2017] [Indexed: 12/15/2022]
Affiliation(s)
- Jennifer Fredlund
- Unité “Dynamique des interactions hôte-pathogène”; Institut Pasteur; Paris France
| | - José Carlos Santos
- Unité “Dynamique des interactions hôte-pathogène”; Institut Pasteur; Paris France
| | - Virginie Stévenin
- Unité “Dynamique des interactions hôte-pathogène”; Institut Pasteur; Paris France
| | - Allon Weiner
- Unité “Dynamique des interactions hôte-pathogène”; Institut Pasteur; Paris France
| | | | - Katya Rechav
- Department of Interfaces; The Weizmann Institute of Sciences; Rehovot Israel
| | | | | | - Michael Elbaum
- Department of Interfaces; The Weizmann Institute of Sciences; Rehovot Israel
| | - Jost Enninga
- Unité “Dynamique des interactions hôte-pathogène”; Institut Pasteur; Paris France
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76
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Santi-Rocca J, Blanchard N. Membrane trafficking and remodeling at the host-parasite interface. Curr Opin Microbiol 2017; 40:145-151. [PMID: 29175340 DOI: 10.1016/j.mib.2017.11.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 10/14/2017] [Accepted: 11/13/2017] [Indexed: 11/16/2022]
Abstract
Membrane shape is functionally linked with many cellular processes. The limiting membrane of vacuoles containing Toxoplasma gondii and Plasmodium apicomplexan parasites lies at the host-parasite interface. This membrane comprises intra-vacuolar and extra-vacuolar tubulo-vesicular deformations, which influence host-parasite cross-talk. Here, underscoring specificities and similarities between the T. gondii and Plasmodium contexts, we present recent findings about vacuolar membrane remodeling and its potential roles in parasite fitness and immune recognition. We review in particular the implication of tubulo-vesicular structures in trapping and/or transporting host and parasite components. Understanding how membrane remodeling influences host-pathogen interactions is expected to be critical in the battle against many intracellular pathogens beyond parasites.
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Affiliation(s)
- Julien Santi-Rocca
- Centre de Physiopathologie de Toulouse Purpan (CPTP), INSERM, CNRS, Université de Toulouse, UPS, Toulouse, France
| | - Nicolas Blanchard
- Centre de Physiopathologie de Toulouse Purpan (CPTP), INSERM, CNRS, Université de Toulouse, UPS, Toulouse, France.
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77
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Sprenger M, Kasper L, Hensel M, Hube B. Metabolic adaptation of intracellular bacteria and fungi to macrophages. Int J Med Microbiol 2017; 308:215-227. [PMID: 29150190 DOI: 10.1016/j.ijmm.2017.11.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 09/21/2017] [Accepted: 11/05/2017] [Indexed: 02/07/2023] Open
Abstract
The mature phagosome of macrophages is a hostile environment for the vast majority of phagocytosed microbes. In addition to active destruction of the engulfed microbes by antimicrobial compounds, restriction of essential nutrients in the phagosomal compartment contributes to microbial growth inhibition and killing. However, some pathogenic microorganisms have not only developed various strategies to efficiently withstand or counteract antimicrobial activities, but also to acquire nutrients within macrophages for intracellular replication. Successful intracellular pathogens are able to utilize host-derived amino acids, carbohydrates and lipids as well as trace metals and vitamins during intracellular growth. This requires sophisticated strategies such as phagosome modification or escape, efficient nutrient transporters and metabolic adaptation. In this review, we discuss the metabolic adaptation of facultative intracellular bacteria and fungi to the intracellular lifestyle inside macrophages.
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Affiliation(s)
- Marcel Sprenger
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology, Hans-Knoell-Institute, Jena, Germany
| | - Lydia Kasper
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology, Hans-Knoell-Institute, Jena, Germany
| | - Michael Hensel
- Division of Microbiology, University Osnabrück, Osnabrück, Germany
| | - Bernhard Hube
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology, Hans-Knoell-Institute, Jena, Germany; Friedrich Schiller University, Jena, Germany; Center for Sepsis Control and Care, University Hospital, Jena, Germany.
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78
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Salmonella exploits the host endolysosomal tethering factor HOPS complex to promote its intravacuolar replication. PLoS Pathog 2017; 13:e1006700. [PMID: 29084291 PMCID: PMC5679646 DOI: 10.1371/journal.ppat.1006700] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 11/09/2017] [Accepted: 10/18/2017] [Indexed: 12/22/2022] Open
Abstract
Salmonella enterica serovar typhimurium extensively remodels the host late endocytic compartments to establish its vacuolar niche within the host cells conducive for its replication, also known as the Salmonella-containing vacuole (SCV). By maintaining a prolonged interaction with late endosomes and lysosomes of the host cells in the form of interconnected network of tubules (Salmonella-induced filaments or SIFs), Salmonella gains access to both membrane and fluid-phase cargo from these compartments. This is essential for maintaining SCV membrane integrity and for bacterial intravacuolar nutrition. Here, we have identified the multisubunit lysosomal tethering factor—HOPS (HOmotypic fusion and Protein Sorting) complex as a crucial host factor facilitating delivery of late endosomal and lysosomal content to SCVs, providing membrane for SIF formation, and nutrients for intravacuolar bacterial replication. Accordingly, depletion of HOPS subunits significantly reduced the bacterial load in non-phagocytic and phagocytic cells as well as in a mouse model of Salmonella infection. We found that Salmonella effector SifA in complex with its binding partner; SKIP, interacts with HOPS subunit Vps39 and mediates recruitment of this tethering factor to SCV compartments. The lysosomal small GTPase Arl8b that binds to, and promotes membrane localization of Vps41 (and other HOPS subunits) was also required for HOPS recruitment to SCVs and SIFs. Our findings suggest that Salmonella recruits the host late endosomal and lysosomal membrane fusion machinery to its vacuolar niche for access to host membrane and nutrients, ensuring its intracellular survival and replication. Intracellular pathogens have devised various strategies to subvert the host membrane trafficking pathways for their growth and survival inside the host cells. Salmonella is one such successful intracellular pathogen that redirects membrane and nutrients from the host endocytic compartments to its replicative niche known as the Salmonella-containing vacuole (SCV) via establishing an interconnected network of tubules (Salmonella-induced filaments or SIFs) that form a continuum with the SCVs. How Salmonella ensures a constant supply of endocytic cargo required for its survival and growth remained unexplored. Our work uncovers a strategy evolved by Salmonella wherein it secretes a bacterial effector into the host cytosol that recruits component of host vesicle fusion machinery-HOPS complex to SCVs and SIFs. HOPS complex promotes docking of the late endocytic compartments at the SCV membrane, prior to their fusion. Thus, depletion of HOPS subunits both in cultured cell lines as well as a mouse model inhibits Salmonella replication, likely due to reduced access to host membranes and nutrients by the vacuolar bacteria. These findings provide mechanistic insights into how this pathogen reroutes the host’s endocytic transport towards its vacuole, ensuring its own intracellular survival and replication.
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79
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Anderson CJ, Kendall MM. Salmonella enterica Serovar Typhimurium Strategies for Host Adaptation. Front Microbiol 2017; 8:1983. [PMID: 29075247 PMCID: PMC5643478 DOI: 10.3389/fmicb.2017.01983] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 09/26/2017] [Indexed: 12/21/2022] Open
Abstract
Bacterial pathogens must sense and respond to newly encountered host environments to regulate the expression of critical virulence factors that allow for niche adaptation and successful colonization. Among bacterial pathogens, non-typhoidal serovars of Salmonella enterica, such as serovar Typhimurium (S. Tm), are a primary cause of foodborne illnesses that lead to hospitalizations and deaths worldwide. S. Tm causes acute inflammatory diarrhea that can progress to invasive systemic disease in susceptible patients. The gastrointestinal tract and intramacrophage environments are two critically important niches during S. Tm infection, and each presents unique challenges to limit S. Tm growth. The intestinal tract is home to billions of commensal microbes, termed the microbiota, which limits the amount of available nutrients for invading pathogens such as S. Tm. Therefore, S. Tm encodes strategies to manipulate the commensal population and side-step this nutritional competition. During subsequent stages of disease, S. Tm resists host immune cell mechanisms of killing. Host cells use antimicrobial peptides, acidification of vacuoles, and nutrient limitation to kill phagocytosed microbes, and yet S. Tm is able to subvert these defense systems. In this review, we discuss recently described molecular mechanisms that S. Tm uses to outcompete the resident microbiota within the gastrointestinal tract. S. Tm directly eliminates close competitors via bacterial cell-to-cell contact as well as by stimulating a host immune response to eliminate specific members of the microbiota. Additionally, S. Tm tightly regulates the expression of key virulence factors that enable S. Tm to withstand host immune defenses within macrophages. Additionally, we highlight the chemical and physical signals that S. Tm senses as cues to adapt to each of these environments. These strategies ultimately allow S. Tm to successfully adapt to these two disparate host environments. It is critical to better understand bacterial adaptation strategies because disruption of these pathways and mechanisms, especially those shared by multiple pathogens, may provide novel therapeutic intervention strategies.
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Affiliation(s)
- Christopher J Anderson
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine,, Charlottesville, VA, United States
| | - Melissa M Kendall
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine,, Charlottesville, VA, United States
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80
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Castanheira S, García-Del Portillo F. Salmonella Populations inside Host Cells. Front Cell Infect Microbiol 2017; 7:432. [PMID: 29046870 PMCID: PMC5632677 DOI: 10.3389/fcimb.2017.00432] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 09/20/2017] [Indexed: 11/13/2022] Open
Abstract
Bacteria of the Salmonella genus cause diseases ranging from gastroenteritis to life-threatening typhoid fever and are among the most successful intracellular pathogens known. After the invasion of the eukaryotic cell, Salmonella exhibits contrasting lifestyles with different replication rates and subcellular locations. Although Salmonella hyper-replicates in the cytosol of certain host cell types, most invading bacteria remain within vacuoles in which the pathogen proliferates at moderate rates or persists in a dormant-like state. Remarkably, these cytosolic and intra-vacuolar intracellular lifestyles are not mutually exclusive and can co-exist in the same infected host cell. The mechanisms that direct the invading bacterium to follow the cytosolic or intra-vacuolar “pathway” remain poorly understood. In vitro studies show predominance of either the cytosolic or the intra-vacuolar population depending on the host cell type invaded by the pathogen. The host and pathogen factors controlling phagosomal membrane integrity and, as consequence, the egress into the cytosol, are intensively investigated. Other aspects of major interest are the host defenses that may affect differentially the cytosolic and intra-vacuolar populations and the strategies used by the pathogen to circumvent these attacks. Here, we summarize current knowledge about these Salmonella intracellular subpopulations and discuss how they emerge during the interaction of this pathogen with the eukaryotic cell.
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Affiliation(s)
- Sónia Castanheira
- Laboratory of Intracellular Bacterial Pathogens, Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología-Consejo Superior de Investigaciones Científicas (CNB-CSIC), Madrid, Spain
| | - Francisco García-Del Portillo
- Laboratory of Intracellular Bacterial Pathogens, Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología-Consejo Superior de Investigaciones Científicas (CNB-CSIC), Madrid, Spain
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81
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Namakchian M, Kassler K, Sticht H, Hensel M, Deiwick J. Structure-based functional analysis of effector protein SifA in living cells reveals motifs important for Salmonella intracellular proliferation. Int J Med Microbiol 2017; 308:84-96. [PMID: 28939436 DOI: 10.1016/j.ijmm.2017.09.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2017] [Revised: 09/02/2017] [Accepted: 09/04/2017] [Indexed: 02/01/2023] Open
Abstract
The facultative intracellular pathogen Salmonella enterica survives and replicates inside the Salmonella-containing vacuole (SCV) of mammalian host cells. SifA is a key effector protein translocated by a type III secretion system and involved in formation of Salmonella-induced filaments (SIF), extensive tubular endosomal compartments. Recruitment of LAMP1 (lysosomal-associated membrane protein 1)-positive membranes to SIF ensures integrity and dynamics of the membrane network. The binding of SifA to the host protein SKIP (SifA and kinesin interacting protein) was proposed as crucial for this function. Due to structural mimicry SifA has further been proposed to interact with G-proteins. We conducted a mutational study of SifA to identify domains and amino acid residues specifically relevant for intracellular replication and SIF formation. Mutations were designed based on the available structural data of SifA and its interface with SKIP, or modeled for SifA as putative guanine nucleotide exchange factor. We developed a live cell imaging-based approach for volume quantification of the SIF network that allowed determination of subtle changes in SIF network and performed a comprehensive analysis of mutant forms of SifA by this approach. We found that the SifA catalytic loop of WxxxE effectors is as important for SIF formation and intracellular proliferation as the SKIP interaction motif, or the CAAX motif for membrane anchoring of SifA.
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Affiliation(s)
| | - Kristin Kassler
- Institut für Biochemie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Heinrich Sticht
- Institut für Biochemie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Michael Hensel
- Abt. Mikrobiologie, Universität Osnabrück, Osnabrück, Germany.
| | - Jörg Deiwick
- Abt. Mikrobiologie, Universität Osnabrück, Osnabrück, Germany.
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82
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Bumann D, Schothorst J. Intracellular Salmonella metabolism. Cell Microbiol 2017; 19. [PMID: 28672057 DOI: 10.1111/cmi.12766] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 06/27/2017] [Accepted: 06/30/2017] [Indexed: 12/28/2022]
Abstract
Growth of Salmonella inside infected host cells is a key aspect of their ability to cause local enteritis or systemic disease. This growth depends on exploitation of host nutrients through a large Salmonella metabolism network with hundreds of metabolites and enzymes. Studies in cell culture infection models are unravelling more and more of the underlying molecular and cellular mechanisms but also show striking Salmonella metabolic plasticity depending on host cell line and experimental conditions. In vivo studies have revealed a qualitatively diverse, but quantitatively poor, host-Salmonella nutritional interface, which on one side makes Salmonella fitness largely resilient against metabolic perturbations, but on the other side severely limits Salmonella biomass generation and growth rates. This review discusses goals and techniques for studying Salmonella intracellular metabolism, summarises main results and implications, and proposes key issues that could be addressed in future studies.
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Affiliation(s)
- Dirk Bumann
- Focal Area Infection Biology, Biozentrum, University of Basel, Basel, Switzerland
| | - Joep Schothorst
- Focal Area Infection Biology, Biozentrum, University of Basel, Basel, Switzerland
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83
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Jennings E, Thurston TL, Holden DW. Salmonella SPI-2 Type III Secretion System Effectors: Molecular Mechanisms And Physiological Consequences. Cell Host Microbe 2017; 22:217-231. [DOI: 10.1016/j.chom.2017.07.009] [Citation(s) in RCA: 202] [Impact Index Per Article: 28.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 06/14/2017] [Accepted: 07/19/2017] [Indexed: 11/30/2022]
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84
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Knuff K, Finlay BB. What the SIF Is Happening-The Role of Intracellular Salmonella-Induced Filaments. Front Cell Infect Microbiol 2017; 7:335. [PMID: 28791257 PMCID: PMC5524675 DOI: 10.3389/fcimb.2017.00335] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 07/10/2017] [Indexed: 11/29/2022] Open
Abstract
A common strategy among intracellular bacterial pathogens is to enter into a vacuolar environment upon host cell invasion. One such pathogen, Salmonella enterica, resides within the Salmonella-containing vacuole (SCV) inside epithelial cells and macrophages. Salmonella hijacks the host endosomal system to establish this unique intracellular replicative niche, forming a highly complex and dynamic network of Salmonella-induced filaments (SIFs). SIFs radiate outwards from the SCV upon onset of bacterial replication. SIF biogenesis is dependent on the activity of bacterial effector proteins secreted by the Salmonella-pathogenicity island-2 (SPI-2) encoded type III secretion system. While the presence of SIFs has been known for almost 25 years, their precise role during infection remains elusive. This review summarizes our current knowledge of SCV maturation and SIF biogenesis, and recent advances in our understanding of the role of SIFs inside cells.
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Affiliation(s)
- Katelyn Knuff
- Michael Smith Laboratories, University of British ColumbiaVancouver, BC, Canada.,Department of Microbiology and Immunology, University of British ColumbiaVancouver, BC, Canada
| | - B Brett Finlay
- Michael Smith Laboratories, University of British ColumbiaVancouver, BC, Canada.,Department of Microbiology and Immunology, University of British ColumbiaVancouver, BC, Canada.,Department of Biochemistry and Molecular Biology, University of British ColumbiaVancouver, BC, Canada
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