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Graham CI, MacMartin TL, de Kievit TR, Brassinga AKC. Molecular regulation of virulence in Legionella pneumophila. Mol Microbiol 2024; 121:167-195. [PMID: 37908155 DOI: 10.1111/mmi.15172] [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: 05/31/2023] [Revised: 09/15/2023] [Accepted: 09/17/2023] [Indexed: 11/02/2023]
Abstract
Legionella pneumophila is a gram-negative bacteria found in natural and anthropogenic aquatic environments such as evaporative cooling towers, where it reproduces as an intracellular parasite of cohabiting protozoa. If L. pneumophila is aerosolized and inhaled by a susceptible person, bacteria may colonize their alveolar macrophages causing the opportunistic pneumonia Legionnaires' disease. L. pneumophila utilizes an elaborate regulatory network to control virulence processes such as the Dot/Icm Type IV secretion system and effector repertoire, responding to changing nutritional cues as their host becomes depleted. The bacteria subsequently differentiate to a transmissive state that can survive in the environment until a replacement host is encountered and colonized. In this review, we discuss the lifecycle of L. pneumophila and the molecular regulatory network that senses nutritional depletion via the stringent response, a link to stationary phase-like metabolic changes via alternative sigma factors, and two-component systems that are homologous to stress sensors in other pathogens, to regulate differentiation between the intracellular replicative phase and more transmissible states. Together, we highlight how this prototypic intracellular pathogen offers enormous potential in understanding how molecular mechanisms enable intracellular parasitism and pathogenicity.
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Affiliation(s)
- Christopher I Graham
- Department of Microbiology, Faculty of Science, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Teassa L MacMartin
- Department of Microbiology, Faculty of Science, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Teresa R de Kievit
- Department of Microbiology, Faculty of Science, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Ann Karen C Brassinga
- Department of Microbiology, Faculty of Science, University of Manitoba, Winnipeg, Manitoba, Canada
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2
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Zhuang C, Zhao J, Zhang S, Shahid M. Escherichia coli infection mediates pyroptosis via activating p53-p21 pathway-regulated apoptosis and cell cycle arrest in bovine mammary epithelial cells. Microb Pathog 2023; 184:106338. [PMID: 37683833 DOI: 10.1016/j.micpath.2023.106338] [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: 08/07/2023] [Revised: 09/05/2023] [Accepted: 09/05/2023] [Indexed: 09/10/2023]
Abstract
Escherichia coli (E. coli) is a major environmental pathogen that causes mammary tissue damage and cell death, which results in substantial economic losses. Pyroptosis, a novel form of programmed cell death characterized by DNA fragmentation, chromatin condensation, cell swelling and leakage of cell contents, often occurs after inflammatory apoptotic pathways activation. Our objective was to investigate the intraction between E. coli infection and bovine mammary epithelial cells (bMECs) with pyroptosis and to explore the underlying regulatory mechanism. bMECs were infected with E. coli for 6 h. Lactic dehydrogenase activities, interleukin (IL)-10, IL-1β, IL-18 and tumor necrosis factor-α concentrations, total apoptosis indexes, and protein expressions of P-cdc25c, P-CDK1, cleaved caspase 9, cleaved caspase 3, cleaved PARP, P-NF-κB, NLRP3, ASC, caspase 1, gasdermin D N-terminal, IL-1β and IL-18 were significantly increased in E. coli infected bMECs. Whereas, cell membrane potential, protein levels of cdc25c, CDK1, cyclin B1, and Bcl-2/Bax level were markedly reduced. Furthermore, Ac-DEVD-CHO (specific inhibitor of apoptosis) dramatically suppressed pyroptosis in bMECs. Moreover, expressions of p53 and p21 promptly improved after E. coli infection, however, Pifithrin-α (specific inhibitor of p53) inhibited p53-p21 pathway, apoptosis, cell cycle arrest and pyroptosis. These results elaborated that E. coli infection of bMECs induced pyroptosis through activating the p53-p21 pathway-mediated apoptosis and cell cycle arrest. Taken together, inhibition of pyroptosis via suppressing of p53-p21 pathway may be an effective therapeutic approach for treating E. coli-induced mastitis, offering efficient theoretical support for the protection and treatment of bovine mastitis.
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Affiliation(s)
- Cuicui Zhuang
- College of Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi, 030801, PR China.
| | - Jinhui Zhao
- College of Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi, 030801, PR China
| | - Shiyao Zhang
- China Agricultural Science and Technology Press Ltd, Beijing, 100081, PR China
| | - Muhammad Shahid
- Center of Microbiology and Biotechnology, Veterinary Research Institute, Khyber Pakhtunkhwa, Peshawar, 25000, Pakistan
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3
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Subramanian A, Wang L, Moss T, Voorhies M, Sangwan S, Stevenson E, Pulido EH, Kwok S, Chalkley RJ, Li KH, Krogan NJ, Swaney DL, Burlingame AL, Floor SN, Sil A, Walter P, Mukherjee S. A Legionella toxin exhibits tRNA mimicry and glycosyl transferase activity to target the translation machinery and trigger a ribotoxic stress response. Nat Cell Biol 2023; 25:1600-1615. [PMID: 37857833 PMCID: PMC11005034 DOI: 10.1038/s41556-023-01248-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 09/01/2023] [Indexed: 10/21/2023]
Abstract
A widespread strategy employed by pathogens to establish infection is to inhibit host-cell protein synthesis. Legionella pneumophila, an intracellular bacterial pathogen and the causative organism of Legionnaires' disease, secretes a subset of protein effectors into host cells that inhibit translation elongation. Mechanistic insights into how the bacterium targets translation elongation remain poorly defined. We report here that the Legionella effector SidI functions in an unprecedented way as a transfer-RNA mimic that directly binds to and glycosylates the ribosome. The 3.1 Å cryo-electron microscopy structure of SidI reveals an N-terminal domain with an 'inverted L' shape and surface-charge distribution characteristic of tRNA mimicry, and a C-terminal domain that adopts a glycosyl transferase fold that licenses SidI to utilize GDP-mannose as a sugar precursor. This coupling of tRNA mimicry and enzymatic action endows SidI with the ability to block protein synthesis with a potency comparable to ricin, one of the most powerful toxins known. In Legionella-infected cells, the translational pausing activated by SidI elicits a stress response signature mimicking the ribotoxic stress response, which is activated by elongation inhibitors that induce ribosome collisions. SidI-mediated effects on the ribosome activate the stress kinases ZAKα and p38, which in turn drive an accumulation of the protein activating transcription factor 3 (ATF3). Intriguingly, ATF3 escapes the translation block imposed by SidI, translocates to the nucleus and orchestrates the transcription of stress-inducible genes that promote cell death, revealing a major role for ATF3 in the response to collided ribosome stress. Together, our findings elucidate a novel mechanism by which a pathogenic bacterium employs tRNA mimicry to hijack a ribosome-to-nuclear signalling pathway that regulates cell fate.
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Affiliation(s)
- Advait Subramanian
- G.W. Hooper Foundation, University of California at San Francisco, San Francisco, CA, USA
- Department of Microbiology and Immunology, University of California at San Francisco, San Francisco, CA, USA
- Department of Biochemistry and Biophysics, University of California at San Francisco, San Francisco, CA, USA
| | - Lan Wang
- Department of Biochemistry and Biophysics, University of California at San Francisco, San Francisco, CA, USA
| | - Tom Moss
- G.W. Hooper Foundation, University of California at San Francisco, San Francisco, CA, USA
- Department of Microbiology and Immunology, University of California at San Francisco, San Francisco, CA, USA
| | - Mark Voorhies
- Department of Microbiology and Immunology, University of California at San Francisco, San Francisco, CA, USA
| | - Smriti Sangwan
- Department of Biochemistry and Biophysics, University of California at San Francisco, San Francisco, CA, USA
| | - Erica Stevenson
- Gladstone Institute of Data Science and Biotechnology, J. Gladstone Institutes, San Francisco, CA, USA
- Department of Cellular and Molecular Pharmacology, University of California at San Francisco, San Francisco, CA, USA
- Quantitative Biosciences Institute, University of California at San Francisco, San Francisco, CA, USA
| | - Ernst H Pulido
- Gladstone Institute of Data Science and Biotechnology, J. Gladstone Institutes, San Francisco, CA, USA
| | - Samentha Kwok
- Department of Cell and Tissue Biology, University of California at San Francisco, San Francisco, CA, USA
| | - Robert J Chalkley
- Mass Spectrometry Facility, Department of Pharmaceutical Chemistry, University of California at San Francisco, San Francisco, CA, USA
| | - Kathy H Li
- Mass Spectrometry Facility, Department of Pharmaceutical Chemistry, University of California at San Francisco, San Francisco, CA, USA
| | - Nevan J Krogan
- Gladstone Institute of Data Science and Biotechnology, J. Gladstone Institutes, San Francisco, CA, USA
- Department of Cellular and Molecular Pharmacology, University of California at San Francisco, San Francisco, CA, USA
- Quantitative Biosciences Institute, University of California at San Francisco, San Francisco, CA, USA
| | - Danielle L Swaney
- Gladstone Institute of Data Science and Biotechnology, J. Gladstone Institutes, San Francisco, CA, USA
- Department of Cellular and Molecular Pharmacology, University of California at San Francisco, San Francisco, CA, USA
- Quantitative Biosciences Institute, University of California at San Francisco, San Francisco, CA, USA
| | - Alma L Burlingame
- Mass Spectrometry Facility, Department of Pharmaceutical Chemistry, University of California at San Francisco, San Francisco, CA, USA
| | - Stephen N Floor
- Department of Cell and Tissue Biology, University of California at San Francisco, San Francisco, CA, USA
- Helen Diller Family Comprehensive Cancer Center, University of California at San Francisco, San Francisco, CA, USA
| | - Anita Sil
- Department of Microbiology and Immunology, University of California at San Francisco, San Francisco, CA, USA
- Chan Zuckerberg Biohub, San Francisco, CA, USA
| | - Peter Walter
- Department of Biochemistry and Biophysics, University of California at San Francisco, San Francisco, CA, USA.
- Howard Hughes Medical Institute, University of California at San Francisco, San Francisco, CA, USA.
- Bay Area Institute of Science, Altos Labs, Redwood City, CA, USA.
| | - Shaeri Mukherjee
- G.W. Hooper Foundation, University of California at San Francisco, San Francisco, CA, USA.
- Department of Microbiology and Immunology, University of California at San Francisco, San Francisco, CA, USA.
- Chan Zuckerberg Biohub, San Francisco, CA, USA.
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4
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In Search of a Mechanistic Link between Chlamydia trachomatis-Induced Cellular Pathophysiology and Oncogenesis. Infect Immun 2023; 91:e0044322. [PMID: 36695575 PMCID: PMC9933725 DOI: 10.1128/iai.00443-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Centrosome duplication and cell cycle progression are essential cellular processes that must be tightly controlled to ensure cellular integrity. Despite their complex regulatory mechanisms, microbial pathogens have evolved sophisticated strategies to co-opt these processes to promote infection. While misregulation of these processes can greatly benefit the pathogen, the consequences to the host cell can be devastating. During infection, the obligate intracellular pathogen Chlamydia trachomatis induces gross cellular abnormalities, including supernumerary centrosomes, multipolar spindles, and defects in cytokinesis. While these observations were made over 15 years ago, identification of the bacterial factors responsible has been elusive due to the genetic intractability of Chlamydia. Recent advances in techniques of genetic manipulation now allows for the direct linking of bacterial virulence factors to manipulation of centrosome duplication and cell cycle progression. In this review, we discuss the impact, both immediate and downstream, of C. trachomatis infection on the host cell cycle regulatory apparatus and centrosome replication. We highlight links between C. trachomatis infection and cervical and ovarian cancers and speculate whether perturbations of the cell cycle and centrosome are sufficient to initiate cellular transformation. We also explore the biological mechanisms employed by Inc proteins and other secreted effector proteins implicated in the perturbation of these host cell pathways. Future work is needed to better understand the nuances of each effector's mechanism and their collective impact on Chlamydia's ability to induce host cellular abnormalities.
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5
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Zhang H, Ma W, Liu H, Tang W, Shu J, Zhou J, Zheng H, Xiao H, Yang X, Liu D, Liang H, Yang X. Systematic analysis of lysine crotonylation in human macrophages responding to MRSA infection. Front Cell Infect Microbiol 2023; 13:1126350. [PMID: 36844408 PMCID: PMC9945341 DOI: 10.3389/fcimb.2023.1126350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Accepted: 01/24/2023] [Indexed: 02/11/2023] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most commonly encountered bacteria found in healthcare clinics and has been ranked a priority 2 pathogen. Research is urgently needed to develop new therapeutic approaches to combat the pathogen. Variations in the pattern of protein posttranslational modifications (PTMs) of host cells affect physiological and pathological events, as well as therapeutic effectiveness. However, the role of crotonylation in MRSA-infected THP1 cells remains unknown. In this study, we found that crotonylation profiles of THP1 cells were altered after MRSA infection. It was then confirmed that lysine crotonylation profiles of THP1 cells and bacteria were different; MRSA infection inhibited global lysine crotonylation (Kcro) modification but partially elevated Kcro of host proteins. We obtained a proteome-wide crotonylation profile of THP1 cells infected by MRSA further treated by vancomycin, leading to the identification of 899 proteins, 1384 sites of which were down-regulated, and 160 proteins with 193 sites up-regulated. The crotonylated down-regulated proteins were mainly located in cytoplasm and were enriched in spliceosome, RNA degradation, protein posttranslational modification, and metabolism. However, the crotonylated up-regulated proteins were mainly located in nucleus and significantly involved in nuclear body, chromosome, ribonucleoprotein complex, and RNA processing. The domains of these proteins were significantly enriched on RNA recognition motif, and linker histone H1 and H5 families. Some proteins related to protecting against bacterial infection were also found to be targets of crotonylation. The present findings point to a comprehensive understanding of the biological functions of lysine crotonylation in human macrophages, thereby providing a certain research basis for the mechanism and targeted therapy on the immune response of host cells against MRSA infection.
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Affiliation(s)
- Hao Zhang
- Department of Wound Infection and Drug, State Key Laboratory of Trauma, Burn and Combined Injury, Daping Hospital, Army Medical University (Third Military Medical University), Chongqing, China
- Deparment of Critical Care Medicine, Daping Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Wei Ma
- Department of Wound Infection and Drug, State Key Laboratory of Trauma, Burn and Combined Injury, Daping Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Haoru Liu
- Department of Wound Infection and Drug, State Key Laboratory of Trauma, Burn and Combined Injury, Daping Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Wanqi Tang
- Department of Wound Infection and Drug, State Key Laboratory of Trauma, Burn and Combined Injury, Daping Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Junjie Shu
- Department of Wound Infection and Drug, State Key Laboratory of Trauma, Burn and Combined Injury, Daping Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Jianping Zhou
- College of Basic Medical Sciences, Panzihua University, Panzihua, China
| | - Hongsheng Zheng
- Department of Wound Infection and Drug, State Key Laboratory of Trauma, Burn and Combined Injury, Daping Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Hongyan Xiao
- Department of Wound Infection and Drug, State Key Laboratory of Trauma, Burn and Combined Injury, Daping Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Xue Yang
- Department of Wound Infection and Drug, State Key Laboratory of Trauma, Burn and Combined Injury, Daping Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Daoyan Liu
- Department of Wound Infection and Drug, State Key Laboratory of Trauma, Burn and Combined Injury, Daping Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Huaping Liang
- Department of Wound Infection and Drug, State Key Laboratory of Trauma, Burn and Combined Injury, Daping Hospital, Army Medical University (Third Military Medical University), Chongqing, China
- *Correspondence: Huaping Liang, ; Xia Yang,
| | - Xia Yang
- Department of Wound Infection and Drug, State Key Laboratory of Trauma, Burn and Combined Injury, Daping Hospital, Army Medical University (Third Military Medical University), Chongqing, China
- *Correspondence: Huaping Liang, ; Xia Yang,
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6
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Lockwood DC, Amin H, Costa TRD, Schroeder GN. The Legionella pneumophila Dot/Icm type IV secretion system and its effectors. MICROBIOLOGY (READING, ENGLAND) 2022; 168. [PMID: 35639581 DOI: 10.1099/mic.0.001187] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
To prevail in the interaction with eukaryotic hosts, many bacterial pathogens use protein secretion systems to release virulence factors at the host–pathogen interface and/or deliver them directly into host cells. An outstanding example of the complexity and sophistication of secretion systems and the diversity of their protein substrates, effectors, is the Defective in organelle trafficking/Intracellular multiplication (Dot/Icm) Type IVB secretion system (T4BSS) of
Legionella pneumophila
and related species.
Legionella
species are facultative intracellular pathogens of environmental protozoa and opportunistic human respiratory pathogens. The Dot/Icm T4BSS translocates an exceptionally large number of effectors, more than 300 per
L. pneumophila
strain, and is essential for evasion of phagolysosomal degradation and exploitation of protozoa and human macrophages as replicative niches. Recent technological advancements in the imaging of large protein complexes have provided new insight into the architecture of the T4BSS and allowed us to propose models for the transport mechanism. At the same time, significant progress has been made in assigning functions to about a third of
L. pneumophila
effectors, discovering unprecedented new enzymatic activities and concepts of host subversion. In this review, we describe the current knowledge of the workings of the Dot/Icm T4BSS machinery and provide an overview of the activities and functions of the to-date characterized effectors in the interaction of
L. pneumophila
with host cells.
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Affiliation(s)
- Daniel C Lockwood
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, BT9 7BL, Northern Ireland, UK
| | - Himani Amin
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College, London, SW7 2AZ, UK
| | - Tiago R D Costa
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College, London, SW7 2AZ, UK
| | - Gunnar N Schroeder
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, BT9 7BL, Northern Ireland, UK
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7
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Glycosylating Effectors of Legionella pneumophila: Finding the Sweet Spots for Host Cell Subversion. Biomolecules 2022; 12:biom12020255. [PMID: 35204756 PMCID: PMC8961657 DOI: 10.3390/biom12020255] [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: 10/22/2021] [Revised: 01/30/2022] [Accepted: 01/31/2022] [Indexed: 02/04/2023] Open
Abstract
Work over the past two decades clearly defined a significant role of glycosyltransferase effectors in the infection strategy of the Gram-negative, respiratory pathogen Legionella pneumophila. Identification of the glucosyltransferase effectors Lgt1-3, specifically modifying elongation factor eEF1A, disclosed a novel mechanism of host protein synthesis manipulation by pathogens and illuminated its impact on the physiological state of the target cell, in particular cell cycle progression and immune and stress responses. Recent characterization of SetA as a general O-glucosyltransferase with a wide range of targets including the proteins Rab1 and Snx1, mediators of membrane transport processes, and the discovery of new types of glycosyltransferases such as LtpM and SidI indicate that the vast effector arsenal might still hold more so-far unrecognized family members with new catalytic features and substrates. In this article, we review our current knowledge regarding these fascinating biomolecules and discuss their role in introducing new or overriding endogenous post-translational regulatory mechanisms enabling the subversion of eukaryotic cells by L. pneumophila.
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8
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Lisowski C, Dias J, Costa S, Silva RJ, Mano M, Eulalio A. Dysregulated endolysosomal trafficking in cells arrested in the G 1 phase of the host cell cycle impairs Salmonella vacuolar replication. Autophagy 2021; 18:1785-1800. [PMID: 34781820 DOI: 10.1080/15548627.2021.1999561] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
Modulation of the host cell cycle has emerged as a common theme among the pathways regulated by bacterial pathogens, arguably to promote host cell colonization. However, in most cases the exact benefit ensuing from such interference to the infection process remains unclear. Previously, we have shown that Salmonella actively induces G2/M arrest of host cells, and that infection is severely inhibited in cells arrested in G1. In this study, we demonstrate that Salmonella vacuolar replication is inhibited in host cells blocked in G1, whereas the cytosolic replication of the closely related pathogen Shigella is not affected. Mechanistically, we show that cells arrested in G1, but not cells arrested in G2, present dysregulated endolysosomal trafficking, displaying an abnormal accumulation of vesicles positive for late endosomal and lysosomal markers. In addition, the macroautophagic/autophagic flux and degradative lysosomal function are strongly impaired. This endolysosomal trafficking dysregulation results in sustained activation of the SPI-1 type III secretion system and lack of vacuole repair by the autophagy pathway, ultimately compromising the maturation and integrity of the Salmonella-containing vacuole. As such, Salmonella is released in the host cytosol. Collectively, our findings demonstrate that the modulation of the host cell cycle occurring during Salmonella infection is related to a disparity in the permissivity of cells arrested in G1 and G2/M, due to their intrinsic characteristics.
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Affiliation(s)
- Clivia Lisowski
- Host RNA Metabolism Group, Institute for Molecular Infection Biology (IMIB), University of Würzburg, Würzburg, Germany
| | - Jane Dias
- RNA & Infection Laboratory, Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Coimbra, Portugal.,Functional Genomics and RNA-based Therapeutics Laboratory, Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Coimbra, Portugal.,PhD Programme in Experimental Biology and Biomedicine (PDBEB), Institute for Interdisciplinary Research (IIIUC), University of Coimbra, Coimbra, Portugal
| | - Susana Costa
- RNA & Infection Laboratory, Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Coimbra, Portugal.,Functional Genomics and RNA-based Therapeutics Laboratory, Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Coimbra, Portugal.,PhD Programme in Experimental Biology and Biomedicine (PDBEB), Institute for Interdisciplinary Research (IIIUC), University of Coimbra, Coimbra, Portugal
| | - Ricardo Jorge Silva
- Functional Genomics and RNA-based Therapeutics Laboratory, Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Coimbra, Portugal.,PhD Programme in Experimental Biology and Biomedicine (PDBEB), Institute for Interdisciplinary Research (IIIUC), University of Coimbra, Coimbra, Portugal
| | - Miguel Mano
- Functional Genomics and RNA-based Therapeutics Laboratory, Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Coimbra, Portugal.,Department of Life Sciences, University of Coimbra, Coimbra, Portugal
| | - Ana Eulalio
- Host RNA Metabolism Group, Institute for Molecular Infection Biology (IMIB), University of Würzburg, Würzburg, Germany.,RNA & Infection Laboratory, Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Coimbra, Portugal.,Department of Life Sciences, University of Coimbra, Coimbra, Portugal
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9
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Abstract
Intracellular proliferation of Legionella pneumophila within a vacuole in human alveolar macrophages is essential for manifestation of Legionnaires’ pneumonia. Intravacuolar growth of the pathogen is totally dependent on remodeling the L. pneumophila-containing vacuole (LCV) by the ER and on its evasion of the endosomal-lysosomal degradation pathway. Diversion of the Legionella pneumophila-containing vacuole (LCV) from the host endosomal-lysosomal degradation pathway is one of the main virulence features essential for manifestation of Legionnaires’ pneumonia. Many of the ∼350 Dot/Icm-injected effectors identified in L. pneumophila have been shown to interfere with various host pathways and processes, but no L. pneumophila effector has ever been identified to be indispensable for lysosomal evasion. While most single effector mutants of L. pneumophila do not exhibit a defective phenotype within macrophages, we show that the MavE effector is essential for intracellular growth of L. pneumophila in human monocyte-derived macrophages (hMDMs) and amoebae and for intrapulmonary proliferation in mice. The mavE null mutant fails to remodel the LCV with endoplasmic reticulum (ER)-derived vesicles and is trafficked to the lysosomes where it is degraded, similar to formalin-killed bacteria. During infection of hMDMs, the MavE effector localizes to the poles of the LCV membrane. The crystal structure of MavE, resolved to 1.8 Å, reveals a C-terminal transmembrane helix, three copies of tyrosine-based sorting motifs, and an NPxY eukaryotic motif, which binds phosphotyrosine-binding domains present on signaling and adaptor eukaryotic proteins. Two point mutations within the NPxY motif result in attenuation of L. pneumophila in both hMDMs and amoeba. The substitution defects of P78 and D64 are associated with failure of vacuoles harboring the mutant to be remodeled by the ER and results in fusion of the vacuole to the lysosomes leading to bacterial degradation. Therefore, the MavE effector of L. pneumophila is indispensable for phagosome biogenesis and lysosomal evasion.
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10
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The metaeffector MesI regulates the activity of the Legionella effector SidI through direct protein-protein interactions. Microbes Infect 2021; 23:104794. [PMID: 33571674 DOI: 10.1016/j.micinf.2021.104794] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 12/10/2020] [Accepted: 01/26/2021] [Indexed: 12/25/2022]
Abstract
To create an intracellular niche permissive for its replication, Legionella pneumophila uses hundreds of effectors to target a wide variety of host proteins and manipulate specific host processes such as immune response, and vesicle trafficking. To avoid unwanted disruption of host physiology, this pathogen also imposes precise control of its virulence by the use of effectors called metaeffectors to regulate the activity of other effectors. A number of effector/metaeffector pairs with distinct regulatory mechanisms have been characterized, including abrogation of protein modifications, direct modification of the effector and direct binding to the catalytic pocket of the cognate effector. Recently, MesI (Lpg2505) was found to be a metaeffector of SidI, an effector involved in inhibiting host protein translation. Here we demonstrate that MesI functions by inhibiting the activity of SidI via direct protein-protein interactions. We show that this interaction occurs within L. pneumophila and thus interferes with the translocation of SidI into host cells. We also solved the structure of MesI, which suggests that this protein does not have an active site similar to any known enzymes. Analysis of deletion mutants allowed the identification of regions within SidI and MesI that are important for their interactions.
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11
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Li P, Vassiliadis D, Ong SY, Bennett-Wood V, Sugimoto C, Yamagishi J, Hartland EL, Pasricha S. Legionella pneumophila Infection Rewires the Acanthamoeba castellanii Transcriptome, Highlighting a Class of Sirtuin Genes. Front Cell Infect Microbiol 2020; 10:428. [PMID: 32974218 PMCID: PMC7468528 DOI: 10.3389/fcimb.2020.00428] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Accepted: 07/14/2020] [Indexed: 12/13/2022] Open
Abstract
Legionella pneumophila is an environmental bacterium that has evolved to survive predation by soil and water amoebae such as Acanthamoeba castellanii, and this has inadvertently led to the ability of L. pneumophila to survive and replicate in human cells. L. pneumophila causes Legionnaire's Disease, with human exposure occurring via the inhalation of water aerosols containing both amoebae and the bacteria. These aerosols originate from aquatic biofilms found in artifical water sources, such as air-conditioning cooling towers and humidifiers. In these man-made environments, A. castellanii supports L. pneumophila intracellular replication, thereby promoting persistence and dissemination of the bacteria and providing protection from external stress. Despite this close evolutionary relationship, very little is known about how A. castellanii responds to L. pneumophila infection. In this study, we examined the global transcriptional response of A. castellanii to L. pneumophila infection. We compared A. castellanii infected with wild type L. pneumophila to A. castellanii infected with an isogenic ΔdotA mutant strain, which is unable to replicate intracellularly. We showed that A. castellanii underwent clear morphological and transcriptional rewiring over the course of L. pneumophila infection. Through improved annotation of the A. castellanii genome, we determined that these transcriptional changes primarily involved biological processes utilizing small GTPases, including cellular transport, signaling, metabolism and replication. In addition, a number of sirtuin-encoding genes in A. castellanii were found to be conserved and upregulated during L. pneumophila infection. Silencing of sirtuin gene, sir6f (ACA1_153540) resulted in the inhibition of A. castellanii cell proliferation during infection and reduced L. pneumophila replication. Overall our findings identified several biological pathways in amoebae that may support L. pneumophila replication and A. castellanii proliferation in environmental conditions.
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Affiliation(s)
- Pengfei Li
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, VIC, Australia.,Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, Australia
| | - Dane Vassiliadis
- Cancer Research Division, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia
| | - Sze Ying Ong
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, VIC, Australia
| | - Vicki Bennett-Wood
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, Australia
| | - Chihiro Sugimoto
- Global Station for Zoonosis Control, GI-CoRE, Hokkaido University, Sapporo, Japan.,Research Center for Zoonosis Control, Hokkaido University, Sapporo, Japan
| | - Junya Yamagishi
- Global Station for Zoonosis Control, GI-CoRE, Hokkaido University, Sapporo, Japan.,Research Center for Zoonosis Control, Hokkaido University, Sapporo, Japan
| | - Elizabeth L Hartland
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, VIC, Australia.,Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, Australia.,Research Center for Zoonosis Control, Hokkaido University, Sapporo, Japan.,Department of Molecular and Translational Science, Monash University, Clayton, VIC, Australia
| | - Shivani Pasricha
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, VIC, Australia.,Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, Australia
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12
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Belyi Y. Targeting Eukaryotic mRNA Translation by Legionella pneumophila. Front Mol Biosci 2020; 7:80. [PMID: 32411722 PMCID: PMC7201127 DOI: 10.3389/fmolb.2020.00080] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 04/07/2020] [Indexed: 02/01/2023] Open
Abstract
Legionella is a gram-negative microorganism and an infectious agent of pneumonia in humans. It is an intracellular pathogen and multiplies in different eukaryotic cells like amoebae, ciliated protozoa, macrophages, monocytes, and lung epithelial cells. Proliferation of L. pneumophila in eukaryotic cells depends on its type 4 secretion system, which delivers an arsenal of bacterial effector proteins to cytoplasm of its host. Once within the cytoplasm, effectors modify a broad range of host activities, including mRNA translation. Translation is inhibited by Legionella through the action of several effector proteins including Lgt1, Lgt2, Lgt3, SidI, LegK4, SidL, and RavX. Lgt1-3 and SidI target elongation factors: Lgt1-3 mono-glucosylate elongation factor eEF1A, while SidI binds eEF1A, and eEF1Bγ. Effector LegK4 inhibits protein synthesis by phosphorylating Hsp70 proteins, while SidL and RavX have no defined targets in protein synthesis machinery thus far. In addition to direct inhibition of protein synthesis, SidI also affects the stress response, whereas Lgt1-3 – unfolded protein response and cell-cycle progression of host cells. Whether manipulation of these processes is linked to canonical or non-canonical function(s) of targeted elongation factors remains unknown.
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Affiliation(s)
- Yury Belyi
- Gamaleya Research Centre for Epidemiology and Microbiology, Moscow, Russia
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13
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Budzik JM, Swaney DL, Jimenez-Morales D, Johnson JR, Garelis NE, Repasy T, Roberts AW, Popov LM, Parry TJ, Pratt D, Ideker T, Krogan NJ, Cox JS. Dynamic post-translational modification profiling of Mycobacterium tuberculosis-infected primary macrophages. eLife 2020; 9:e51461. [PMID: 31951200 PMCID: PMC7030789 DOI: 10.7554/elife.51461] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Accepted: 01/16/2020] [Indexed: 12/23/2022] Open
Abstract
Macrophages are highly plastic cells with critical roles in immunity, cancer, and tissue homeostasis, but how these distinct cellular fates are triggered by environmental cues is poorly understood. To uncover how primary murine macrophages respond to bacterial pathogens, we globally assessed changes in post-translational modifications of proteins during infection with Mycobacterium tuberculosis, a notorious intracellular pathogen. We identified hundreds of dynamically regulated phosphorylation and ubiquitylation sites, indicating that dramatic remodeling of multiple host pathways, both expected and unexpected, occurred during infection. Most of these cellular changes were not captured by mRNA profiling, and included activation of ubiquitin-mediated autophagy, an evolutionarily ancient cellular antimicrobial system. This analysis also revealed that a particular autophagy receptor, TAX1BP1, mediates clearance of ubiquitylated Mtb and targets bacteria to LC3-positive phagophores. These studies provide a new resource for understanding how macrophages shape their proteome to meet the challenge of infection.
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Affiliation(s)
- Jonathan M Budzik
- Department of MedicineUniversity of California, San FranciscoSan FranciscoUnited States
- Department of Molecular and Cell BiologyUniversity of California, BerkeleyBerkeleyUnited States
| | - Danielle L Swaney
- Department of Cellular and Molecular PharmacologyUniversity of California, San FranciscoSan FranciscoUnited States
- Quantitative Biosciences InstituteUniversity of California, San FranciscoSan FranciscoUnited States
- Gladstone InstitutesSan FranciscoUnited States
| | - David Jimenez-Morales
- Department of Cellular and Molecular PharmacologyUniversity of California, San FranciscoSan FranciscoUnited States
- Quantitative Biosciences InstituteUniversity of California, San FranciscoSan FranciscoUnited States
- Gladstone InstitutesSan FranciscoUnited States
- Department of Medicine, Division of Cardiovascular MedicineStanford UniversityStanfordUnited States
| | - Jeffrey R Johnson
- Department of Cellular and Molecular PharmacologyUniversity of California, San FranciscoSan FranciscoUnited States
- Quantitative Biosciences InstituteUniversity of California, San FranciscoSan FranciscoUnited States
- Gladstone InstitutesSan FranciscoUnited States
| | - Nicholas E Garelis
- Department of Molecular and Cell BiologyUniversity of California, BerkeleyBerkeleyUnited States
| | - Teresa Repasy
- Department of Molecular and Cell BiologyUniversity of California, BerkeleyBerkeleyUnited States
| | - Allison W Roberts
- Department of Molecular and Cell BiologyUniversity of California, BerkeleyBerkeleyUnited States
| | - Lauren M Popov
- Department of Molecular and Cell BiologyUniversity of California, BerkeleyBerkeleyUnited States
| | - Trevor J Parry
- Department of Molecular and Cell BiologyUniversity of California, BerkeleyBerkeleyUnited States
| | - Dexter Pratt
- Department of MedicineUniversity of California, San DiegoLa JollaUnited States
| | - Trey Ideker
- Department of MedicineUniversity of California, San DiegoLa JollaUnited States
| | - Nevan J Krogan
- Department of Cellular and Molecular PharmacologyUniversity of California, San FranciscoSan FranciscoUnited States
- Quantitative Biosciences InstituteUniversity of California, San FranciscoSan FranciscoUnited States
- Gladstone InstitutesSan FranciscoUnited States
| | - Jeffery S Cox
- Department of Molecular and Cell BiologyUniversity of California, BerkeleyBerkeleyUnited States
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14
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Abstract
Bacteria participate in a wide diversity of symbiotic associations with eukaryotic hosts that require precise interactions for bacterial recognition and persistence. Most commonly, host-associated bacteria interfere with host gene expression to modulate the immune response to the infection. However, many of these bacteria also interfere with host cellular differentiation pathways to create a hospitable niche, resulting in the formation of novel cell types, tissues, and organs. In both of these situations, bacterial symbionts must interact with eukaryotic regulatory pathways. Here, we detail what is known about how bacterial symbionts, from pathogens to mutualists, control host cellular differentiation across the central dogma, from epigenetic chromatin modifications, to transcription and mRNA processing, to translation and protein modifications. We identify four main trends from this survey. First, mechanisms for controlling host gene expression appear to evolve from symbionts co-opting cross-talk between host signaling pathways. Second, symbiont regulatory capacity is constrained by the processes that drive reductive genome evolution in host-associated bacteria. Third, the regulatory mechanisms symbionts exhibit correlate with the cost/benefit nature of the association. And, fourth, symbiont mechanisms for interacting with host genetic regulatory elements are not bound by native bacterial capabilities. Using this knowledge, we explore how the ubiquitous intracellular Wolbachia symbiont of arthropods and nematodes may modulate host cellular differentiation to manipulate host reproduction. Our survey of the literature on how infection alters gene expression in Wolbachia and its hosts revealed that, despite their intermediate-sized genomes, different strains appear capable of a wide diversity of regulatory manipulations. Given this and Wolbachia's diversity of phenotypes and eukaryotic-like proteins, we expect that many symbiont-induced host differentiation mechanisms will be discovered in this system.
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Affiliation(s)
- Shelbi L Russell
- Department of Molecular Cell and Developmental Biology, University of California, Santa Cruz, CA, USA.
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15
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Kjellin J, Pränting M, Bach F, Vaid R, Edelbroek B, Li Z, Hoeppner MP, Grabherr M, Isberg RR, Hagedorn M, Söderbom F. Investigation of the host transcriptional response to intracellular bacterial infection using Dictyostelium discoideum as a host model. BMC Genomics 2019; 20:961. [PMID: 31823727 PMCID: PMC6902447 DOI: 10.1186/s12864-019-6269-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 11/07/2019] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND During infection by intracellular pathogens, a highly complex interplay occurs between the infected cell trying to degrade the invader and the pathogen which actively manipulates the host cell to enable survival and proliferation. Many intracellular pathogens pose important threats to human health and major efforts have been undertaken to better understand the host-pathogen interactions that eventually determine the outcome of the infection. Over the last decades, the unicellular eukaryote Dictyostelium discoideum has become an established infection model, serving as a surrogate macrophage that can be infected with a wide range of intracellular pathogens. In this study, we use high-throughput RNA-sequencing to analyze the transcriptional response of D. discoideum when infected with Mycobacterium marinum and Legionella pneumophila. The results were compared to available data from human macrophages. RESULTS The majority of the transcriptional regulation triggered by the two pathogens was found to be unique for each bacterial challenge. Hallmark transcriptional signatures were identified for each infection, e.g. induction of endosomal sorting complexes required for transport (ESCRT) and autophagy genes in response to M. marinum and inhibition of genes associated with the translation machinery and energy metabolism in response to L. pneumophila. However, a common response to the pathogenic bacteria was also identified, which was not induced by non-pathogenic food bacteria. Finally, comparison with available data sets of regulation in human monocyte derived macrophages shows that the elicited response in D. discoideum is in many aspects similar to what has been observed in human immune cells in response to Mycobacterium tuberculosis and L. pneumophila. CONCLUSIONS Our study presents high-throughput characterization of D. discoideum transcriptional response to intracellular pathogens using RNA-seq. We demonstrate that the transcriptional response is in essence distinct to each pathogen and that in many cases, the corresponding regulation is recapitulated in human macrophages after infection by mycobacteria and L. pneumophila. This indicates that host-pathogen interactions are evolutionary conserved, derived from the early interactions between free-living phagocytic cells and bacteria. Taken together, our results strengthen the use of D. discoideum as a general infection model.
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Affiliation(s)
- Jonas Kjellin
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden.
| | - Maria Pränting
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden.,Present Address: ReAct - Action on Antibiotic Resistance, Department of Medical Sciences, Uppsala University, Uppsala, Sweden
| | - Frauke Bach
- Section Parasitology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany.,Present Address: Department of Stem Cell Transplantation, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Roshan Vaid
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden.,Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Bart Edelbroek
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Zhiru Li
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA, 02111, USA.,Present Address: New England Biolabs, Ipswich, MA, USA
| | - Marc P Hoeppner
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden.,Institute of Clinical Molecular Biology, Kiel University, University Hospital Schleswig-Holstein, Kiel, Germany
| | - Manfred Grabherr
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Ralph R Isberg
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA, 02111, USA
| | - Monica Hagedorn
- Section Parasitology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany.,Life Sciences and Chemistry, Jacobs University Bremen gGmbH, Group Ribogenetics, Bremen, Germany
| | - Fredrik Söderbom
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden.
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