1
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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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Yang Y, Mei L, Chen J, Chen X, Wang Z, Liu L, Yang A. Legionella pneumophila-mediated host posttranslational modifications. J Mol Cell Biol 2023; 15:mjad032. [PMID: 37156500 PMCID: PMC10720952 DOI: 10.1093/jmcb/mjad032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 01/17/2023] [Accepted: 05/06/2023] [Indexed: 05/10/2023] Open
Abstract
Legionella pneumophila is a Gram-negative bacterium ubiquitously present in freshwater environments and causes a serious type of pneumonia called Legionnaires' disease. During infections, L. pneumophila releases over 300 effector proteins into host cells through an Icm/Dot type IV secretion system to manipulate the host defense system for survival within the host. Notably, certain effector proteins mediate posttranslational modifications (PTMs), serving as useful approaches exploited by L. pneumophila to modify host proteins. Some effectors catalyze the addition of host protein PTMs, while others mediate the removal of PTMs from host proteins. In this review, we summarize L. pneumophila effector-mediated PTMs of host proteins, including phosphorylation, ubiquitination, glycosylation, AMPylation, phosphocholination, methylation, and ADP-ribosylation, as well as dephosphorylation, deubiquitination, deAMPylation, deADP-ribosylation, dephosphocholination, and delipidation. We describe their molecular mechanisms and biological functions in the regulation of bacterial growth and Legionella-containing vacuole biosynthesis and in the disruption of host immune and defense machinery.
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Affiliation(s)
- Yi Yang
- School of Life Sciences, Chongqing University, Chongqing 401331, China
| | - Ligang Mei
- School of Life Sciences, Chongqing University, Chongqing 401331, China
| | - Jing Chen
- School of Life Sciences, Chongqing University, Chongqing 401331, China
| | - Xiaorong Chen
- School of Life Sciences, Chongqing University, Chongqing 401331, China
| | - Zhuolin Wang
- School of Life Sciences, Chongqing University, Chongqing 401331, China
| | - Lu Liu
- School of Life Sciences, Chongqing University, Chongqing 401331, China
| | - Aimin Yang
- School of Life Sciences, Chongqing University, Chongqing 401331, China
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3
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Wehrmann M, Vilchez D. The emerging role and therapeutic implications of bacterial and parasitic deubiquitinating enzymes. Front Immunol 2023; 14:1303072. [PMID: 38077335 PMCID: PMC10703165 DOI: 10.3389/fimmu.2023.1303072] [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: 09/27/2023] [Accepted: 11/03/2023] [Indexed: 12/18/2023] Open
Abstract
Deubiquitinating enzymes (DUBs) are emerging as key factors for the infection of human cells by pathogens such as bacteria and parasites. In this review, we discuss the most recent studies on the role of deubiquitinase activity in exploiting and manipulating ubiquitin (Ub)-dependent host processes during infection. The studies discussed here highlight the importance of DUB host-pathogen research and underscore the therapeutic potential of inhibiting pathogen-specific DUB activity to prevent infectious diseases.
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Affiliation(s)
- Markus Wehrmann
- Cologne Excellence Cluster for Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
- Institute for Integrated Stress Response Signaling, Faculty of Medicine, University Hospital Cologne, Cologne, Germany
| | - David Vilchez
- Cologne Excellence Cluster for Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
- Institute for Integrated Stress Response Signaling, Faculty of Medicine, University Hospital Cologne, Cologne, Germany
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
- Institute for Genetics, University of Cologne, Cologne, Germany
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4
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Roberts CG, Franklin TG, Pruneda JN. Ubiquitin-targeted bacterial effectors: rule breakers of the ubiquitin system. EMBO J 2023; 42:e114318. [PMID: 37555693 PMCID: PMC10505922 DOI: 10.15252/embj.2023114318] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 07/10/2023] [Accepted: 07/18/2023] [Indexed: 08/10/2023] Open
Abstract
Regulation through post-translational ubiquitin signaling underlies a large portion of eukaryotic biology. This has not gone unnoticed by invading pathogens, many of which have evolved mechanisms to manipulate or subvert the host ubiquitin system. Bacteria are particularly adept at this and rely heavily upon ubiquitin-targeted virulence factors for invasion and replication. Despite lacking a conventional ubiquitin system of their own, many bacterial ubiquitin regulators loosely follow the structural and mechanistic rules established by eukaryotic ubiquitin machinery. Others completely break these rules and have evolved novel structural folds, exhibit distinct mechanisms of regulation, or catalyze foreign ubiquitin modifications. Studying these interactions can not only reveal important aspects of bacterial pathogenesis but also shed light on unexplored areas of ubiquitin signaling and regulation. In this review, we discuss the methods by which bacteria manipulate host ubiquitin and highlight aspects that follow or break the rules of ubiquitination.
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Affiliation(s)
- Cameron G Roberts
- Department of Molecular Microbiology & ImmunologyOregon Health & Science UniversityPortlandORUSA
| | - Tyler G Franklin
- Department of Molecular Microbiology & ImmunologyOregon Health & Science UniversityPortlandORUSA
| | - Jonathan N Pruneda
- Department of Molecular Microbiology & ImmunologyOregon Health & Science UniversityPortlandORUSA
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5
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Shi Y, Liu H, Ma K, Luo ZQ, Qiu J. Legionella longbeachae effector protein RavZ inhibits autophagy and regulates phagosome ubiquitination during infection. PLoS One 2023; 18:e0281587. [PMID: 36758031 PMCID: PMC9910735 DOI: 10.1371/journal.pone.0281587] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 01/26/2023] [Indexed: 02/10/2023] Open
Abstract
Legionella organisms are ubiquitous environmental bacteria that are responsible for human Legionnaires' disease, a fatal form of severe pneumonia. These bacteria replicate intracellularly in a wide spectrum of host cells within a distinct compartment termed the Legionella-containing vacuole (LCV). Effector proteins translocated by the Dot/Icm apparatus extensively modulate host cellular functions to aid in the biogenesis of the LCV and intracellular proliferation. RavZ is an L. pneumophila effector that functions as a cysteine protease to hydrolyze lipidated LC3, thereby compromising the host autophagic response to bacterial infection. In this study, we characterized the RavZ (RavZLP) ortholog in L. longbeachae (RavZLLO), the second leading cause of Legionella infections in the world. RavZLLO and RavZLP share approximately 60% sequence identity and a conserved His-Asp-Cys catalytic triad. RavZLLO is recognized by the Dot/Icm systems of both L. pneumophila and L. longbeachae. Upon translocation into the host, it suppresses autophagy signaling in cells challenged with both species, indicating the functional redundancy of RavZLLO and RavZLP. Additionally, ectopic expression of RavZLLO but not RavZLP in mammalian cells reduces the levels of cellular polyubiquitinated and polyneddylated proteins. Consistent with this process, RavZLLO regulates the accumulation of polyubiquitinated species on the LCV during L. longbeachae infection.
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Affiliation(s)
- Yunjia Shi
- State Key Laboratory for Zoonotic Diseases, Key Laboratory for Zoonosis Research of the Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Hongtao Liu
- State Key Laboratory for Zoonotic Diseases, Key Laboratory for Zoonosis Research of the Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Kelong Ma
- State Key Laboratory for Zoonotic Diseases, Key Laboratory for Zoonosis Research of the Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Zhao-Qing Luo
- Purdue Institute for Inflammation, Immunology and Infectious Disease and Department of Biological Sciences, Purdue University, West Lafayette, Indiana, United States of America
- * E-mail: (JQ); (ZQL)
| | - Jiazhang Qiu
- State Key Laboratory for Zoonotic Diseases, Key Laboratory for Zoonosis Research of the Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, China
- * E-mail: (JQ); (ZQL)
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6
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Chen Y, Cao B, Zheng W, Xu T. ACKR4a induces autophagy to block NF-κB signaling and apoptosis to facilitate Vibrio harveyi infection. iScience 2023; 26:106105. [PMID: 36843837 PMCID: PMC9947386 DOI: 10.1016/j.isci.2023.106105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2022] [Revised: 12/03/2022] [Accepted: 01/27/2023] [Indexed: 02/04/2023] Open
Abstract
Autophagy and apoptosis are two recognized mechanisms of resistance to bacterial invasion. However, bacteria have likewise evolved the ability to evade immunity. In this study, we identify ACKR4a, a member of an atypical chemokine receptor family, as a suppressor of the NF-κB pathway, which cooperates with Beclin-1 to induce autophagy to inhibit NF-κB signaling and block apoptosis, facilitating Vibrio harveyi infection. Mechanistically, V. harveyi-induced Ap-1 activates ACKR4a transcription and expression. ACKR4a forms a complex with Beclin-1 and MyD88, respectively, inducing autophagy and transporting MyD88 into the lysosome for degradation to suppress inflammatory cytokine production. Meanwhile, ACKR4a-induced autophagy blocks apoptosis by inhibiting caspase8. This study proves for the first time that V. harveyi uses both autophagy and apoptosis to evade innate immunity, suggesting that V. harveyi has evolved the ability to against fish immunity.
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Affiliation(s)
- Ya Chen
- Laboratory of Fish Molecular Immunology, College of Fisheries and Life Science, Shanghai Ocean University, Shanghai, China
| | - Baolan Cao
- Laboratory of Fish Molecular Immunology, College of Fisheries and Life Science, Shanghai Ocean University, Shanghai, China
| | - Weiwei Zheng
- Laboratory of Fish Molecular Immunology, College of Fisheries and Life Science, Shanghai Ocean University, Shanghai, China
| | - Tianjun Xu
- Laboratory of Fish Molecular Immunology, College of Fisheries and Life Science, Shanghai Ocean University, Shanghai, China
- Laboratory of Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
- Corresponding author
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7
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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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8
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Murata M, Kanamori R, Kitao T, Kubori T, Nagai H, Tagaya M, Arasaki K. Requirement of phosphatidic acid binding for distribution of bacterial protein targeting syntaxin 17. J Cell Sci 2022; 135:274561. [DOI: 10.1242/jcs.259538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 02/17/2022] [Indexed: 11/20/2022] Open
Abstract
A gram-negative bacterium, Legionella pneumophila is known to manipulate the host cellular functions. In these manipulations, bacterial proteins called Legionella effectors that L. pneumophila secretes into the host cytosol are necessary. A Legionella effector, Lpg1137, was identified as a serine protease responsible for degradation of syntaxin 17 (Stx17). However, how Lpg1137 can specifically recognize and degrade Stx17 remains unknown. Given that Stx17 is localized in the ER/mitochondria-associated membrane (MAM)/mitochondria, Lpg1137 likely distributes to these compartments to recognize Stx17. Here we show that the C-terminal region of Lpg1137 binds to phosphatidic acid (PA), a MAM/mitochondria-enriched phospholipid, and that this binding is required for the correct intracellular distribution of Lpg1137. Two basic residues in the C-terminal region are required for PA binding and their mutation causes mislocalization of Lpg1137. This mutant fails to degrade Stx17 while retaining a protease activity. Taken together, our data reveal that Lpg1137 utilizes PA for its distribution to the membranous compartments in which Stx17 is localized.
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Affiliation(s)
- Misaki Murata
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan
| | - Riku Kanamori
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan
| | - Tomoe Kitao
- Department of Microbiology, Graduate School of Medicine, Gifu University, 1-1 Yanagito, Gifu 501-1194, Japan
| | - Tomoko Kubori
- Department of Microbiology, Graduate School of Medicine, Gifu University, 1-1 Yanagito, Gifu 501-1194, Japan
- G-CHAIN, Gifu University, 1-1 Yanagito, Gifu 501-1194, Japan
| | - Hiroki Nagai
- Department of Microbiology, Graduate School of Medicine, Gifu University, 1-1 Yanagito, Gifu 501-1194, Japan
- G-CHAIN, Gifu University, 1-1 Yanagito, Gifu 501-1194, Japan
| | - Mitsuo Tagaya
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan
| | - Kohei Arasaki
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan
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9
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Lau N, Thomas DR, Lee YW, Knodler LA, Newton HJ. Perturbation of ATG16L1 function impairs the biogenesis of Salmonella and Coxiella replication vacuoles. Mol Microbiol 2022; 117:235-251. [PMID: 34874584 PMCID: PMC8844213 DOI: 10.1111/mmi.14858] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Accepted: 12/03/2021] [Indexed: 02/03/2023]
Abstract
Anti-bacterial autophagy, known as xenophagy, is a host innate immune response that targets invading pathogens for degradation. Some intracellular bacteria, such as the enteric pathogen Salmonella enterica serovar Typhimurium (S. Typhimurium), utilize effector proteins to interfere with autophagy. One such S. Typhimurium effector, SopF, inhibits recruitment of ATG16L1 to damaged Salmonella-containing vacuoles (SCVs), thereby inhibiting the host xenophagic response. SopF is also required to maintain the integrity of the SCV during the early stages of infection. Here we show disruption of the SopF-ATG16L1 interaction leads to an increased proportion of cytosolic S. Typhimurium. Furthermore, SopF was utilized as a molecular tool to examine the requirement for ATG16L1 in the intracellular lifestyle of Coxiella burnetii, a bacterium that requires a functional autophagy pathway to replicate efficiently and form a single, spacious vacuole called the Coxiella-containing vacuole (CCV). ATG16L1 is required for CCV expansion and fusion but does not influence C. burnetii replication. In contrast, SopF did not affect CCV formation or replication, demonstrating that the contribution of ATG16L1 to CCV biogenesis is via its role in autophagy, not xenophagy. This study highlights the diverse capabilities of bacterial effector proteins to dissect the molecular details of host-pathogen interactions.
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Affiliation(s)
- Nicole Lau
- The Department of Microbiology and Immunology at the Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
| | - David R Thomas
- The Department of Microbiology and Immunology at the Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
| | - Yi Wei Lee
- The Department of Microbiology and Immunology at the Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
| | - Leigh A Knodler
- The Department of Microbiology and Immunology at the Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia.,Paul G. Allen School for Global Health, College of Veterinary Medicine, Washington State University, Pullman, Washington, USA
| | - Hayley J Newton
- The Department of Microbiology and Immunology at the Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
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10
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Sura T, Surabhi S, Maaß S, Hammerschmidt S, Siemens N, Becher D. The global proteome and ubiquitinome of bacterial and viral co-infected bronchial epithelial cells. J Proteomics 2022; 250:104387. [PMID: 34600154 DOI: 10.1016/j.jprot.2021.104387] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 08/26/2021] [Accepted: 09/22/2021] [Indexed: 12/13/2022]
Abstract
Viral infections facilitate bacterial trafficking to the lower respiratory tract resulting in bacterial-viral co-infections. Bacterial dissemination to the lower respiratory tract is enhanced by influenza A virus induced epithelial cell damage and dysregulation of immune responses. Epithelial cells act as a line of defense and detect pathogens by a high variety of pattern recognition receptors. The post-translational modification ubiquitin is involved in almost every cellular process. Moreover, ubiquitination contributes to the regulation of host immune responses, influenza A virus uncoating and transport within host cells. We applied proteomics with a special focus on ubiquitination to assess the impact of single bacterial and viral as well as bacterial-viral co-infections on bronchial epithelial cells. We used Tandem Ubiquitin Binding Entities to enrich polyubiquitinated proteins and assess changes in the ubiquitinome. Infecting 16HBE cells with Streptococcus pyogenes led to an increased abundance of proteins related to mitochondrial translation and energy metabolism in proteome and ubiquitinome. In contrast, influenza A virus infection mainly altered the ubiquitinome. Co-infections had no additional impact on protein abundances or affected pathways. Changes in protein abundance and enriched pathways were assigned to imprints of both infecting pathogens. SIGNIFICANCE: Viral and bacterial co-infections of the lower respiratory tract are a burden for health systems worldwide. Therefore, it is necessary to elucidate the complex interplay between the host and the infecting pathogens. Thus, we analyzed the proteome and the ubiquitinome of co-infected bronchial epithelial cells to elaborate a potential synergism of the two infecting organisms. The results presented in this work can be used as a starting point for further analyses.
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Affiliation(s)
- Thomas Sura
- University of Greifswald, Center for Functional Genomics of Microbes, Institute of Microbiology, Department of Microbial Proteomics, Felix-Hausdorff-Str. 8, 17489 Greifswald, Germany
| | - Surabhi Surabhi
- University of Greifswald, Center for Functional Genomics of Microbes, Interfaculty Institute for Genetics and Functional Genomics, Department of Molecular Genetics and Infection Biology, Felix-Hausdorff-Str. 8, 17489 Greifswald, Germany
| | - Sandra Maaß
- University of Greifswald, Center for Functional Genomics of Microbes, Institute of Microbiology, Department of Microbial Proteomics, Felix-Hausdorff-Str. 8, 17489 Greifswald, Germany
| | - Sven Hammerschmidt
- University of Greifswald, Center for Functional Genomics of Microbes, Interfaculty Institute for Genetics and Functional Genomics, Department of Molecular Genetics and Infection Biology, Felix-Hausdorff-Str. 8, 17489 Greifswald, Germany
| | - Nikolai Siemens
- University of Greifswald, Center for Functional Genomics of Microbes, Interfaculty Institute for Genetics and Functional Genomics, Department of Molecular Genetics and Infection Biology, Felix-Hausdorff-Str. 8, 17489 Greifswald, Germany
| | - Dörte Becher
- University of Greifswald, Center for Functional Genomics of Microbes, Institute of Microbiology, Department of Microbial Proteomics, Felix-Hausdorff-Str. 8, 17489 Greifswald, Germany.
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11
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Tripathi-Giesgen I, Behrends C, Alpi AF. The ubiquitin ligation machinery in the defense against bacterial pathogens. EMBO Rep 2021; 22:e52864. [PMID: 34515402 PMCID: PMC8567218 DOI: 10.15252/embr.202152864] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 07/21/2021] [Accepted: 08/27/2021] [Indexed: 12/12/2022] Open
Abstract
The ubiquitin system is an important part of the host cellular defense program during bacterial infection. This is in particular evident for a number of bacteria including Salmonella Typhimurium and Mycobacterium tuberculosis which—inventively as part of their invasion strategy or accidentally upon rupture of seized host endomembranes—become exposed to the host cytosol. Ubiquitylation is involved in the detection and clearance of these bacteria as well as in the activation of innate immune and inflammatory signaling. Remarkably, all these defense responses seem to emanate from a dense layer of ubiquitin which coats the invading pathogens. In this review, we focus on the diverse group of host cell E3 ubiquitin ligases that help to tailor this ubiquitin coat. In particular, we address how the divergent ubiquitin conjugation mechanisms of these ligases contribute to the complexity of the anti‐bacterial coating and the recruitment of different ubiquitin‐binding effectors. We also discuss the activation and coordination of the different E3 ligases and which strategies bacteria evolved to evade the activities of the host ubiquitin system.
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Affiliation(s)
- Ishita Tripathi-Giesgen
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Christian Behrends
- Munich Cluster for Systems Neurology (SyNergy), Medical Faculty, Ludwig-Maximilians-University München, München, Germany
| | - Arno F Alpi
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried, Germany
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12
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Liu K, Kong L, Graham DB, Carey KL, Xavier RJ. SAC1 regulates autophagosomal phosphatidylinositol-4-phosphate for xenophagy-directed bacterial clearance. Cell Rep 2021; 36:109434. [PMID: 34320354 PMCID: PMC8327279 DOI: 10.1016/j.celrep.2021.109434] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 12/21/2020] [Accepted: 07/01/2021] [Indexed: 02/07/2023] Open
Abstract
Phosphoinositides are important molecules in lipid signaling, membrane identity, and trafficking that are spatiotemporally controlled by factors from both mammalian cells and intracellular pathogens. Here, using small interfering RNA (siRNA) directed against phosphoinositide kinases and phosphatases, we screen for regulators of the host innate defense response to intracellular bacterial replication. We identify SAC1, a transmembrane phosphoinositide phosphatase, as an essential regulator of xenophagy. Depletion or inactivation of SAC1 compromises fusion between Salmonella-containing autophagosomes and lysosomes, leading to increased bacterial replication. Mechanistically, the loss of SAC1 results in aberrant accumulation of phosphatidylinositol-4-phosphate [PI(4)P] on Salmonella-containing autophagosomes, thus facilitating recruitment of SteA, a PI(4)P-binding Salmonella effector protein, which impedes lysosomal fusion. Replication of Salmonella lacking SteA is suppressed by SAC-1-deficient cells, however, demonstrating bacterial adaptation to xenophagy. Our findings uncover a paradigm in which a host protein regulates the level of its substrate and impairs the function of a bacterial effector during xenophagy.
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Affiliation(s)
- Kai Liu
- Center for Computational and Integrative Biology, Department of Molecular Biology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Lingjia Kong
- Center for Computational and Integrative Biology, Department of Molecular Biology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Daniel B Graham
- Center for Computational and Integrative Biology, Department of Molecular Biology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Center for the Study of Inflammatory Bowel Disease, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA; Klarman Cell Observatory, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | | | - Ramnik J Xavier
- Center for Computational and Integrative Biology, Department of Molecular Biology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Center for the Study of Inflammatory Bowel Disease, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA; Klarman Cell Observatory, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA.
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13
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Kitao T, Taguchi K, Seto S, Arasaki K, Ando H, Nagai H, Kubori T. Legionella Manipulates Non-canonical SNARE Pairing Using a Bacterial Deubiquitinase. Cell Rep 2021; 32:108107. [PMID: 32905772 DOI: 10.1016/j.celrep.2020.108107] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2019] [Revised: 05/30/2020] [Accepted: 08/12/2020] [Indexed: 10/23/2022] Open
Abstract
The intracellular bacterial pathogen Legionella pneumophila uses many effector proteins delivered by the bacterial type IV secretion system (T4SS) to hijack the early secretory pathway to establish its replicative niche, known as the Legionella-containing vacuole (LCV). On LCV biogenesis, the endoplasmic reticulum (ER) vesicular soluble N-ethylmaleimide-sensitive factor attachment protein receptors (v-SNARE) Sec22b is recruited to the bacterial phagosome and forms non-canonical pairings with target membrane SNAREs (t-SNAREs) from the plasma membrane. Here, we identify a Legionella deubiquitinase (DUB), LotB, that can modulate the early secretory pathway by interacting with coatomer protein complex I (COPI) vesicles when ectopically expressed. We show that Sec22b is ubiquitinated upon L. pneumophila infection in a T4SS-dependent manner and that, subsequently, LotB deconjugates K63-linked ubiquitins from Sec22b. The DUB activity of LotB stimulates dissociation of the t-SNARE syntaxin 3 (Stx3) from Sec22b, which resides on the LCV. Our study highlights a bacterial strategy manipulating the dynamics of infection-induced SNARE pairing using a bacterial DUB.
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Affiliation(s)
- Tomoe Kitao
- Department of Microbiology, Graduate School of Medicine, Gifu University, Gifu, Gifu 501-1194, Japan
| | - Kyoichiro Taguchi
- Department of Microbiology, Graduate School of Medicine, Gifu University, Gifu, Gifu 501-1194, Japan; Laboratory of Veterinary Microbiology, Faculty of Applied Biological Science, Gifu University, Gifu, Gifu 501-1193, Japan
| | - Shintaro Seto
- Department of Pathophysiology and Host Defense, The Research Institute of Tuberculosis, Japan Anti-Tuberculosis Association, Kiyose, Tokyo 204-8533, Japan
| | - Kohei Arasaki
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan
| | - Hiroki Ando
- G-CHAIN, Gifu University, Gifu, Gifu 501-1194, Japan; Laboratory of Phage Biologics, Graduate School of Medicine, Gifu University, Gifu, Gifu 501-1194, Japan
| | - Hiroki Nagai
- Department of Microbiology, Graduate School of Medicine, Gifu University, Gifu, Gifu 501-1194, Japan; G-CHAIN, Gifu University, Gifu, Gifu 501-1194, Japan.
| | - Tomoko Kubori
- Department of Microbiology, Graduate School of Medicine, Gifu University, Gifu, Gifu 501-1194, Japan; G-CHAIN, Gifu University, Gifu, Gifu 501-1194, Japan.
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14
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Kitao T, Arasaki K, Nagai H, Kubori T. Protocol for imaging proteins associated with Legionella-containing vacuoles in host cells. STAR Protoc 2021; 2:100410. [PMID: 33870219 PMCID: PMC8042411 DOI: 10.1016/j.xpro.2021.100410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
The intracellular bacterial pathogen Legionella pneumophila exploits host cellular systems using approximately 300 effector proteins to establish a replicative niche known as the Legionella-containing vacuole (LCV). During infection, both host and bacterial proteins interactively function on the LCVs. Here, we describe a detailed step-by-step protocol to visualize proteins associated with LCVs in host cells. This protocol can aid in analyzing whether a protein of interest influences the subcellular localization of LCV-associated proteins during infection. For complete details on the use and execution of this protocol, please refer to Kitao et al. (2020). Step-by-step workflow describing how to infect host cells with intracellular bacteria Identification of subcellular localization of bacterial proteins in host cells Analysis of cellular reorganization of host proteins as a result of infection Protocol is applicable to any intracellular bacteria
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Affiliation(s)
- Tomoe Kitao
- Department of Microbiology, Graduate School of Medicine, Gifu University, Gifu, Gifu 501-1194, Japan
| | - Kohei Arasaki
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan
| | - Hiroki Nagai
- Department of Microbiology, Graduate School of Medicine, Gifu University, Gifu, Gifu 501-1194, Japan.,G-CHAIN, Gifu University, Gifu, Gifu 501-1194, Japan
| | - Tomoko Kubori
- Department of Microbiology, Graduate School of Medicine, Gifu University, Gifu, Gifu 501-1194, Japan.,G-CHAIN, Gifu University, Gifu, Gifu 501-1194, Japan
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15
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Legionella hijacks the host Golgi-to-ER retrograde pathway for the association of Legionella-containing vacuole with the ER. PLoS Pathog 2021; 17:e1009437. [PMID: 33760868 PMCID: PMC8021152 DOI: 10.1371/journal.ppat.1009437] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 04/05/2021] [Accepted: 03/01/2021] [Indexed: 11/19/2022] Open
Abstract
Legionella pneumophila (L. pneumophila) is a gram-negative bacterium that replicates in a compartment that resembles the host endoplasmic reticulum (ER). To create its replicative niche, L. pneumophila manipulates host membrane traffic and fusion machineries. Bacterial proteins called Legionella effectors are translocated into the host cytosol and play a crucial role in these processes. In an early stage of infection, Legionella subverts ER-derived vesicles (ERDVs) by manipulating GTPase Rab1 to facilitate remodeling of the Legionella-containing vacuole (LCV). Subsequently, the LCV associates with the ER in a mechanism that remains elusive. In this study, we show that L. pneumophila recruits GTPases Rab33B and Rab6A, which regulate vesicle trafficking from the Golgi to the ER, to the LCV to promote the association of LCV with the ER. We found that recruitment of Rab6A to the LCV depends on Rab33B. Legionella effector SidE family proteins, which phosphoribosyl-ubiquitinate Rab33B, were found to be necessary for the recruitment of Rab33B to the LCV. Immunoprecipitation experiments revealed that L. pneumophila facilitates the interaction of Rab6 with ER-resident SNAREs comprising syntaxin 18, p31, and BNIP1, but not tethering factors including NAG, RINT-1, and ZW10, which are normally required for syntaxin 18-mediated fusion of Golgi-derived vesicles with the ER. Our results identified a Rab33B-Rab6A cascade on the LCV and the interaction of Rab6 with ER-resident SNARE proteins for the association of LCV with the ER and disclosed the unidentified physiological role of SidE family proteins. Legionella pneumophila causes a sever pneumonia called Legionnaires’ disease and a threat of this disease has increased on a world-wide scale. As a feature of L. pneumophila, it secrets over 300 bacterial effectors to adapt and survive inside the host and many of effectors modify the host proteins in a unique manner. L. pneumophila is known to travel inside the host and final destination of this pathogens is the host ER. In the initial step of this travel, L. pneumophila subverts host early vesicular trafficking to remodel the membrane composition of Legionella-containing vacuole (LCV). Although this remodeling process has been well characterized, the molecular machinery of association of remodeled vacuoles with the ER is still obscure. This paper shows that the host GTPases Rab6A and Rab33B, both of which control Golgi-to-ER traffic, are recruited to the LCV in a cascade manner and are required for the association of LCVs with the ER through the interaction between Rab6A and ER-resident t-SNARE proteins. Of note, we demonstrate that a bacteria-specific Rab33B modification called phosphoribosyl-ubiquitination by Legionella effectors proteins of the SidE family is essential for the recruitment of Rab33B to the LCV.
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16
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Vozandychova V, Stojkova P, Hercik K, Rehulka P, Stulik J. The Ubiquitination System within Bacterial Host-Pathogen Interactions. Microorganisms 2021; 9:638. [PMID: 33808578 PMCID: PMC8003559 DOI: 10.3390/microorganisms9030638] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 03/15/2021] [Accepted: 03/16/2021] [Indexed: 12/17/2022] Open
Abstract
Ubiquitination of proteins, like phosphorylation and acetylation, is an important regulatory aspect influencing numerous and various cell processes, such as immune response signaling and autophagy. The study of ubiquitination has become essential to learning about host-pathogen interactions, and a better understanding of the detailed mechanisms through which pathogens affect ubiquitination processes in host cell will contribute to vaccine development and effective treatment of diseases. Pathogenic bacteria (e.g., Salmonella enterica, Legionella pneumophila and Shigella flexneri) encode many effector proteins, such as deubiquitinating enzymes (DUBs), targeting the host ubiquitin machinery and thus disrupting pertinent ubiquitin-dependent anti-bacterial response. We focus here upon the host ubiquitination system as an integral unit, its interconnection with the regulation of inflammation and autophagy, and primarily while examining pathogens manipulating the host ubiquitination system. Many bacterial effector proteins have already been described as being translocated into the host cell, where they directly regulate host defense processes. Due to their importance in pathogenic bacteria progression within the host, they are regarded as virulence factors essential for bacterial evasion. However, in some cases (e.g., Francisella tularensis) the host ubiquitination system is influenced by bacterial infection, although the responsible bacterial effectors are still unknown.
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Affiliation(s)
- Vera Vozandychova
- Department of Molecular Pathology and Biology, Faculty of Military Health Sciences, University of Defence, Trebesska 1575, 50001 Hradec Kralove, Czech Republic; (V.V.); (P.S.); (K.H.); (P.R.)
| | - Pavla Stojkova
- Department of Molecular Pathology and Biology, Faculty of Military Health Sciences, University of Defence, Trebesska 1575, 50001 Hradec Kralove, Czech Republic; (V.V.); (P.S.); (K.H.); (P.R.)
| | - Kamil Hercik
- Department of Molecular Pathology and Biology, Faculty of Military Health Sciences, University of Defence, Trebesska 1575, 50001 Hradec Kralove, Czech Republic; (V.V.); (P.S.); (K.H.); (P.R.)
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo namesti 542/2, 16000 Prague, Czech Republic
| | - Pavel Rehulka
- Department of Molecular Pathology and Biology, Faculty of Military Health Sciences, University of Defence, Trebesska 1575, 50001 Hradec Kralove, Czech Republic; (V.V.); (P.S.); (K.H.); (P.R.)
| | - Jiri Stulik
- Department of Molecular Pathology and Biology, Faculty of Military Health Sciences, University of Defence, Trebesska 1575, 50001 Hradec Kralove, Czech Republic; (V.V.); (P.S.); (K.H.); (P.R.)
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17
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Mei L, Qiu X, Jiang C, Yang A. Host Delipidation Mediated by Bacterial Effectors. Trends Microbiol 2020; 29:238-250. [PMID: 33092951 DOI: 10.1016/j.tim.2020.09.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 09/28/2020] [Accepted: 09/29/2020] [Indexed: 12/19/2022]
Abstract
Protein lipidation, the covalent attachment of a lipid moiety to a target protein, plays a critical role in many cellular processes in eukaryotic cells. Bacterial pathogens secrete various effectors to subvert the host signaling pathway as a mechanism of microbial pathogenesis. An increasing number of effectors from diverse bacterial pathogens function as cysteine proteases to cause irreversible delipidation of host lipidated proteins. This in turn results in disruption of crucial lipidation-mediated host signal transduction, thereby enabling pathogen survival and replication. In this review, we discuss the role of the bacterial effectors in interactions with the host and highlight our knowledge of irreversible host delipidation, with a focus on the common concerted biochemical mechanisms of the bacterial effectors.
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Affiliation(s)
- Ligang Mei
- School of Life Sciences, Chongqing University, Chongqing 401331, China
| | - Xiaofeng Qiu
- School of Life Sciences, Chongqing University, Chongqing 401331, China
| | - Chen Jiang
- School of Life Sciences, Chongqing University, Chongqing 401331, China
| | - Aimin Yang
- School of Life Sciences, Chongqing University, Chongqing 401331, China; Ultrafast Transient Materials Science Center, Institute of Advanced Interdisciplinary Studies, Chongqing University, Chongqing 401331, China.
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18
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Russell KL, Gorgulho CM, Allen A, Vakaki M, Wang Y, Facciabene A, Lee D, Roy P, Buchser WJ, Appleman LJ, Maranchie J, Storkus WJ, Lotze MT. Inhibiting Autophagy in Renal Cell Cancer and the Associated Tumor Endothelium. ACTA ACUST UNITED AC 2020; 25:165-177. [PMID: 31135523 PMCID: PMC10395074 DOI: 10.1097/ppo.0000000000000374] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The clear cell subtype of kidney cancer encompasses most renal cell carcinoma cases and is associated with the loss of von Hippel-Lindau gene function or expression. Subsequent loss or mutation of the other allele influences cellular stress responses involving nutrient and hypoxia sensing. Autophagy is an important regulatory process promoting the disposal of unnecessary or degraded cellular components, tightly linked to almost all cellular processes. Organelles and proteins that become damaged or that are no longer needed in the cell are sequestered and digested in autophagosomes upon fusing with lysosomes, or alternatively, released via vesicular exocytosis. Tumor development tends to disrupt the regulation of the balance between this process and apoptosis, permitting prolonged cell survival and increased replication. Completed trials of autophagic inhibitors using hydroxychloroquine in combination with other anticancer agents including rapalogues and high-dose interleukin 2 have now been reported. The complex nature of autophagy and the unique biology of clear cell renal cell carcinoma warrant further understanding to better develop the next generation of relevant anticancer agents.
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Affiliation(s)
| | | | - Abigail Allen
- Bioengineering, University of Pittsburgh, Pittsburgh, PA
| | | | | | - Andrea Facciabene
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA
| | | | - Partha Roy
- Bioengineering, University of Pittsburgh, Pittsburgh, PA
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19
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Abstract
Autophagy is a conserved and fundamental cellular process mainly to recycle or eliminate dysfunctional cellular organelles or proteins. As a response to cellular stress, autophagy is used as a defense mechanism to combat the infection with pathogenic bacteria. However, many intracellular bacteria have developed diverse mechanisms to evade recognition, to manipulate the autophagic pathway, and to hijack the autophagosomal compartment for replication. In this review, we discuss recent understandings on how bacteria interact with host autophagy.
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Affiliation(s)
- Yao-Wen Wu
- a Department of Chemistry, Umeå Centre for Microbial Research , Umeå University , Umeå , Sweden.,b Chemical Genomics Centre of the Max Planck Society , Dortmund , Germany.,c Max Planck Institute of Molecular Physiology , Dortmund , Germany
| | - Fu Li
- a Department of Chemistry, Umeå Centre for Microbial Research , Umeå University , Umeå , Sweden.,b Chemical Genomics Centre of the Max Planck Society , Dortmund , Germany.,c Max Planck Institute of Molecular Physiology , Dortmund , Germany
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20
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Bacterial DUBs: deubiquitination beyond the seven classes. Biochem Soc Trans 2020; 47:1857-1866. [PMID: 31845741 DOI: 10.1042/bst20190526] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 11/27/2019] [Accepted: 11/28/2019] [Indexed: 12/13/2022]
Abstract
Protein ubiquitination is a posttranslational modification that regulates many aspects of cellular life, including proteostasis, vesicular trafficking, DNA repair and NF-κB activation. By directly targeting intracellular bacteria or bacteria-containing vacuoles to the lysosome, ubiquitination is also an important component of cell-autonomous immunity. Not surprisingly, several pathogenic bacteria encode deubiquitinases (DUBs) and use them as secreted effectors that prevent ubiquitination of bacterial components. A systematic overview of known bacterial DUBs, including their cleavage specificities and biological roles, suggests multiple independent acquisition events from host-encoded DUBs and other proteases. The widely used classification of DUBs into seven well-defined families should only be applied to eukaryotic DUBs, since several bacterial DUBs do not follow this classification.
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21
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Emerging insights into bacterial deubiquitinases. Curr Opin Microbiol 2019; 47:14-19. [DOI: 10.1016/j.mib.2018.10.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 10/05/2018] [Accepted: 10/05/2018] [Indexed: 02/01/2023]
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Best AM, Abu Kwaik Y. Evasion of phagotrophic predation by protist hosts and innate immunity of metazoan hosts by Legionella pneumophila. Cell Microbiol 2018; 21:e12971. [PMID: 30370624 DOI: 10.1111/cmi.12971] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 10/08/2018] [Accepted: 10/24/2018] [Indexed: 12/18/2022]
Abstract
Legionella pneumophila is a ubiquitous environmental bacterium that has evolved to infect and proliferate within amoebae and other protists. It is thought that accidental inhalation of contaminated water particles by humans is what has enabled this pathogen to proliferate within alveolar macrophages and cause pneumonia. However, the highly evolved macrophages are equipped with more sophisticated innate defence mechanisms than are protists, such as the evolution of phagotrophic feeding into phagocytosis with more evolved innate defence processes. Not surprisingly, the majority of proteins involved in phagosome biogenesis (~80%) have origins in the phagotrophy stage of evolution. There are a plethora of highly evolved cellular and innate metazoan processes, not represented in protist biology, that are modulated by L. pneumophila, including TLR2 signalling, NF-κB, apoptotic and inflammatory processes, histone modification, caspases, and the NLRC-Naip5 inflammasomes. Importantly, L. pneumophila infects haemocytes of the invertebrate Galleria mellonella, kill G. mellonella larvae, and proliferate in and kill Drosophila adult flies and Caenorhabditis elegans. Although coevolution with protist hosts has provided a substantial blueprint for L. pneumophila to infect macrophages, we discuss the further evolutionary aspects of coevolution of L. pneumophila and its adaptation to modulate various highly evolved innate metazoan processes prior to becoming a human pathogen.
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Affiliation(s)
- Ashley M Best
- Department of Microbiology and Immunology, College of Medicine, University of Louisville, Louisville, Kentucky
| | - Yousef Abu Kwaik
- Department of Microbiology and Immunology, College of Medicine, University of Louisville, Louisville, Kentucky.,Center for Predictive Medicine, College of Medicine, University of Louisville, Louisville, Kentucky
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23
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Abstract
Within the human host, Legionella pneumophila replicates within alveolar macrophages, leading to pneumonia. However, L. pneumophila is an aquatic generalist pathogen that replicates within a wide variety of protist hosts, including amoebozoa, percolozoa, and ciliophora. The intracellular lifestyles of L. pneumophila within the two evolutionarily distant hosts macrophages and protists are remarkably similar. Coevolution with numerous protist hosts has shaped plasticity of the genome of L. pneumophila, which harbors numerous proteins encoded by genes acquired from primitive eukaryotic hosts through interkingdom horizontal gene transfer. The Dot/Icm type IVb translocation system translocates ∼6,000 effectors among Legionella species and >320 effector proteins in L. pneumophila into host cells to modulate a plethora of cellular processes to create proliferative niches. Since many of the effectors have likely evolved to modulate cellular processes of primitive eukaryotic hosts, it is not surprising that most of the effectors do not contribute to intracellular growth within human macrophages. Some of the effectors may modulate highly conserved eukaryotic processes, while others may target protist-specific processes that are absent in mammals. The lack of studies to determine the role of the effectors in adaptation of L. pneumophila to various protists has hampered the progress to determine the function of most of these effectors, which are routinely studied in mouse or human macrophages. Since many protists restrict L. pneumophila, utilization of such hosts can also be instrumental in deciphering the mechanisms of failure of L. pneumophila to overcome restriction of certain protist hosts. Here, we review the interaction of L. pneumophila with its permissive and restrictive protist environmental hosts and outline the accomplishments as well as gaps in our knowledge of L. pneumophila-protist host interaction and L. pneumophila's evolution to become a human pathogen.
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Affiliation(s)
- Ashley Best
- Department of Microbiology and Immunology, School of Medicine, University of Louisville, Louisville, Kentucky, USA
| | - Yousef Abu Kwaik
- Department of Microbiology and Immunology, School of Medicine, University of Louisville, Louisville, Kentucky, USA
- Center for Predictive Medicine, University of Louisville, Louisville, Kentucky, USA
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24
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Deubiquitinating Enzymes Related to Autophagy: New Therapeutic Opportunities? Cells 2018; 7:cells7080112. [PMID: 30126257 PMCID: PMC6116007 DOI: 10.3390/cells7080112] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 08/13/2018] [Accepted: 08/17/2018] [Indexed: 12/21/2022] Open
Abstract
Autophagy is an evolutionary conserved catabolic process that allows for the degradation of intracellular components by lysosomes. This process can be triggered by nutrient deprivation, microbial infections or other challenges to promote cell survival under these stressed conditions. However, basal levels of autophagy are also crucial for the maintenance of proper cellular homeostasis by ensuring the selective removal of protein aggregates and dysfunctional organelles. A tight regulation of this process is essential for cellular survival and organismal health. Indeed, deregulation of autophagy is associated with a broad range of pathologies such as neuronal degeneration, inflammatory diseases, and cancer progression. Ubiquitination and deubiquitination of autophagy substrates, as well as components of the autophagic machinery, are critical regulatory mechanisms of autophagy. Here, we review the main evidence implicating deubiquitinating enzymes (DUBs) in the regulation of autophagy. We also discuss how they may constitute new therapeutic opportunities in the treatment of pathologies such as cancers, neurodegenerative diseases or infections.
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Spatial, Temporal, and Functional Assessment of LC3-Dependent Autophagy in Shigella flexneri Dissemination. Infect Immun 2018; 86:IAI.00134-18. [PMID: 29844234 DOI: 10.1128/iai.00134-18] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Accepted: 05/22/2018] [Indexed: 12/21/2022] Open
Abstract
Shigella flexneri disseminates within the colonic mucosa by displaying actin-based motility in the cytosol of epithelial cells. Motile bacteria form membrane protrusions that project into adjacent cells and resolve into double-membrane vacuoles (DMVs) from which the bacteria escape, thereby achieving cell-to-cell spread. During dissemination, S. flexneri is targeted by LC3-dependent autophagy, a host cell defense mechanism against intracellular pathogens. The S. flexneri type III secretion system effector protein IcsB was initially proposed to counteract the recruitment of the LC3-dependent autophagy machinery to cytosolic bacteria. However, a recent study proposed that LC3 was recruited to bacteria in DMVs formed during cell-to-cell spread. To resolve the controversy and clarify the role of autophagy in S. flexneri infection, we tracked dissemination using live confocal microscopy and determined the spatial and temporal recruitment of LC3 to bacteria. This approach demonstrated that (i) LC3 was exclusively recruited to wild-type or icsB bacteria located in DMVs and (ii) the icsB mutant was defective in cell-to-cell spread due to failure to escape LC3-positive as well as LC3-negative DMVs. Failure of S. flexneri to escape DMVs correlated with late LC3 recruitment, suggesting that LC3 recruitment is the consequence and not the cause of DMV escape failure. Inhibition of autophagy had no positive impact on the spreading of wild-type or icsB mutant bacteria. Our results unambiguously demonstrate that IcsB is required for DMV escape during cell-to-cell spread, regardless of LC3 recruitment, and do not support the previously proposed notion that autophagy counters S. flexneri dissemination.
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26
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Best A, Jones S, Abu Kwaik Y. Mammalian Solute Carrier (SLC)-like transporters of Legionella pneumophila. Sci Rep 2018; 8:8352. [PMID: 29844490 PMCID: PMC5974234 DOI: 10.1038/s41598-018-26782-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 05/15/2018] [Indexed: 01/07/2023] Open
Abstract
Acquisition of nutrients during intra-vacuolar growth of L. pneumophila within macrophages or amoebae is poorly understood. Since many genes of L. pneumophila are acquired by inter-kingdom horizontal gene transfer from eukaryotic hosts, we examined the presence of human solute carrier (SLC)-like transporters in the L. pneumophila genome using I-TASSER to assess structural alignments. We identified 11 SLC-like putative transporters in L. pneumophila that are structurally similar to SLCs, eight of which are amino acid transporters, and one is a tricarboxylate transporter. The two other transporters, LstA and LstB, are structurally similar to the human glucose transporter, SLC2a1/Glut1. Single mutants of lstA or lstB have decreased ability to import, while the lstA/lstB double mutant is severely defective for uptake of glucose. While lstA or lstB single mutants are not defective in intracellular proliferation within Acanthamoeba polyphaga and human monocyte-derived macrophages, the lstA/lstB double mutant is severely defective in both host cells. The two phenotypic defects of the lstA/lstB double mutant in uptake of glucose and intracellular replication are both restored upon complementation of either lstA or lstB. Our data show that the two glucose transporters, LstA and LstB, are redundant and are required for intracellular replication within human macrophages and amoebae.
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Affiliation(s)
- Ashley Best
- Department of Microbiology and Immunology, School of Medicine, University of Louisville, Louisville, KY, United States
| | - Snake Jones
- Department of Microbiology and Immunology, School of Medicine, University of Louisville, Louisville, KY, United States
| | - Yousef Abu Kwaik
- Department of Microbiology and Immunology, School of Medicine, University of Louisville, Louisville, KY, United States.
- Center for Predictive Medicine, University of Louisville, Louisville, KY, United States.
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27
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Siqueira MDS, Ribeiro RDM, Travassos LH. Autophagy and Its Interaction With Intracellular Bacterial Pathogens. Front Immunol 2018; 9:935. [PMID: 29875765 PMCID: PMC5974045 DOI: 10.3389/fimmu.2018.00935] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2018] [Accepted: 04/16/2018] [Indexed: 12/20/2022] Open
Abstract
Cellular responses to stress can be defined by the overwhelming number of changes that cells go through upon contact with and stressful conditions such as infection and modifications in nutritional status. One of the main cellular responses to stress is autophagy. Much progress has been made in the understanding of the mechanisms involved in the induction of autophagy during infection by intracellular bacteria. This review aims to discuss recent findings on the role of autophagy as a cellular response to intracellular bacterial pathogens such as, Streptococcus pyogenes, Mycobacterium tuberculosis, Shigella flexneri, Salmonella typhimurium, Listeria monocytogenes, and Legionella pneumophila, how the autophagic machinery senses these bacteria directly or indirectly (through the detection of bacteria-induced nutritional stress), and how some of these bacterial pathogens manage to escape from autophagy.
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Affiliation(s)
- Mariana da Silva Siqueira
- Laboratory of Immunoreceptors and Signaling, Immunobiology Program, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Renato de Moraes Ribeiro
- Laboratory of Immunoreceptors and Signaling, Immunobiology Program, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Leonardo H Travassos
- Laboratory of Immunoreceptors and Signaling, Immunobiology Program, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
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28
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Best A, Price C, Ozanic M, Santic M, Jones S, Abu Kwaik Y. A Legionella pneumophila amylase is essential for intracellular replication in human macrophages and amoebae. Sci Rep 2018; 8:6340. [PMID: 29679057 PMCID: PMC5910436 DOI: 10.1038/s41598-018-24724-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 04/05/2018] [Indexed: 11/09/2022] Open
Abstract
Legionella pneumophila invades protozoa with an "accidental" ability to cause pneumonia upon transmission to humans. To support its nutrition during intracellular residence, L. pneumophila relies on host amino acids as the main source of carbon and energy to feed the TCA cycle. Despite the apparent lack of a requirement for glucose for L. pneumophila growth in vitro and intracellularly, the organism contains multiple amylases, which hydrolyze polysaccharides into glucose monomers. Here we describe one predicted putative amylase, LamB, which is uniquely present only in L. pneumophila and L. steigerwaltii among the ~60 species of Legionella. Our data show that LamB has a strong amylase activity, which is abolished upon substitutions of amino acids that are conserved in the catalytic pocket of amylases. Loss of LamB or expression of catalytically-inactive variants of LamB results in a severe growth defect of L. pneumophila in Acanthamoeba polyphaga and human monocytes-derived macrophages. Importantly, the lamB null mutant is severely attenuated in intra-pulmonary proliferation in the mouse model and is defective in dissemination to the liver and spleen. Our data show an essential role for LamB in intracellular replication of L. pneumophila in amoeba and human macrophages and in virulence in vivo.
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Affiliation(s)
- Ashley Best
- Department of Microbiology and Immunology, College of Medicine, University of Louisville, Louisville, KY, USA
| | - Christopher Price
- Department of Microbiology and Immunology, College of Medicine, University of Louisville, Louisville, KY, USA
| | - Mateja Ozanic
- Department of Microbiology and Parasitology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Marina Santic
- Department of Microbiology and Parasitology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Snake Jones
- Department of Microbiology and Immunology, College of Medicine, University of Louisville, Louisville, KY, USA
| | - Yousef Abu Kwaik
- Department of Microbiology and Immunology, College of Medicine, University of Louisville, Louisville, KY, USA.
- Center for Predictive Medicine, University of Louisville, Louisville, KY, USA.
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