1
|
Cobe BL, Dey S, Minasov G, Inniss N, Satchell KJF, Cianciotto NP. Bactericidal effectors of the Stenotrophomonas maltophilia type IV secretion system: functional definition of the nuclease TfdA and structural determination of TfcB. mBio 2024:e0119824. [PMID: 38832773 DOI: 10.1128/mbio.01198-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2024] [Accepted: 04/28/2024] [Indexed: 06/05/2024] Open
Abstract
Stenotrophomonas maltophilia expresses a type IV protein secretion system (T4SS) that promotes contact-dependent killing of other bacteria and does so partly by secreting the effector TfcB. Here, we report the structure of TfcB, comprising an N-terminal domain similar to the catalytic domain of glycosyl hydrolase (GH-19) chitinases and a C-terminal domain for recognition and translocation by the T4SS. Utilizing a two-hybrid assay to measure effector interactions with the T4SS coupling protein VirD4, we documented the existence of five more T4SS substrates. One of these was protein 20845, an annotated nuclease. A S. maltophilia mutant lacking the gene for 20845 was impaired for killing Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa. Moreover, the cloned 20845 gene conferred robust toxicity, with the recombinant E. coli being rescued when 20845 was co-expressed with its cognate immunity protein. The 20845 effector was an 899 amino-acid protein, comprised of a GHH-nuclease domain in its N-terminus, a large central region of indeterminant function, and a C-terminus for secretion. Engineered variants of the 20845 gene that had mutations in the predicted catalytic site did not impede E. coli, indicating that the antibacterial effect of 20845 involves its nuclease activity. Using flow cytometry with DNA staining, we determined that 20845, but not its mutant variants, confers a loss in DNA content of target bacteria. Database searches revealed that uncharacterized homologs of 20845 occur within a range of bacteria. These data indicate that the S. maltophilia T4SS promotes interbacterial competition through the action of multiple toxic effectors, including a potent, novel DNase.IMPORTANCEStenotrophomonas maltophilia is a multi-drug-resistant, Gram-negative bacterium that is an emerging pathogen of humans. Patients with cystic fibrosis are particularly susceptible to S. maltophilia infection. In hospital water systems and various types of infections, S. maltophilia co-exists with other bacteria, including other pathogens such as Pseudomonas aeruginosa. We previously demonstrated that S. maltophilia has a functional VirB/D4 type VI protein secretion system (T4SS) that promotes contact-dependent killing of other bacteria. Since most work on antibacterial systems involves the type VI secretion system, this observation remains noteworthy. Moreover, S. maltophilia currently stands alone as a model for a human pathogen expressing an antibacterial T4SS. Using biochemical, genetic, and cell biological approaches, we now report both the discovery of a novel antibacterial nuclease (TfdA) and the first structural determination of a bactericidal T4SS effector (TfcB).
Collapse
Affiliation(s)
- Brandi L Cobe
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Supratim Dey
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
- Center for Structural Biology of Infectious Diseases, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - George Minasov
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
- Center for Structural Biology of Infectious Diseases, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Nicole Inniss
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
- Center for Structural Biology of Infectious Diseases, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Karla J F Satchell
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
- Center for Structural Biology of Infectious Diseases, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Nicholas P Cianciotto
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| |
Collapse
|
2
|
Kotewicz KM, Zhang M, Kim S, Martin MS, Chowdhury AR, Tai A, Scheck RA, Isberg RR. Sde Proteins Coordinate Ubiquitin Utilization and Phosphoribosylation to Promote Establishment and Maintenance of the Legionella Replication Vacuole. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.09.07.553534. [PMID: 38645023 PMCID: PMC11030226 DOI: 10.1101/2023.09.07.553534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/23/2024]
Abstract
The Legionella pneumophila Sde family of translocated proteins promotes host tubular endoplasmic reticulum (ER) rearrangements that are tightly linked to phosphoribosyl-ubiquitin (pR-Ub) modification of Reticulon 4 (Rtn4). Sde proteins have two additional activities of unclear relevance to the infection process: K63 linkage-specific deubiquitination and phosphoribosyl modification of polyubiquitin (pR-Ub). We show here that the deubiquitination activity (DUB) stimulates ER rearrangements while pR-Ub protects the replication vacuole from cytosolic surveillance by autophagy. Loss of DUB activity was tightly linked to lowered pR-Ub modification of Rtn4, consistent with the DUB activity fueling the production of pR-Ub-Rtn4. In parallel, phosphoribosyl modification of polyUb, in a region of the protein known as the isoleucine patch, prevented binding by the autophagy adapter p62. An inability of Sde mutants to modify polyUb resulted in immediate p62 association, a critical precursor to autophagic attack. The ability of Sde WT to block p62 association decayed quickly after bacterial infection, as predicted by the presence of previously characterized L. pneumophila effectors that inactivate Sde and remove polyUb. In sum, these results show that the accessory Sde activities act to stimulate ER rearrangements and protect from host innate immune sensing in a temporal fashion.
Collapse
Affiliation(s)
- Kristin M Kotewicz
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, 150 Harrison Ave., Boston, MA 02111, USA
- Current address: Gastrointestinal Unit and Center for the Study of Inflammatory Bowel Disease, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114
| | - Mengyun Zhang
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, 150 Harrison Ave., Boston, MA 02111, USA
- Current address: Global Health Drug Discovery Institute, Haidian, Beijing, China
| | - Seongok Kim
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, 150 Harrison Ave., Boston, MA 02111, USA
| | - Meghan S Martin
- Department of Chemistry, Tufts University, 62 Talbot Ave, Medford, MA, 02155, USA
| | - Atish Roy Chowdhury
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, 150 Harrison Ave., Boston, MA 02111, USA
| | - Albert Tai
- Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, 150 Harrison Ave., Boston, MA 02111, USA
| | - Rebecca A Scheck
- Department of Chemistry, Tufts University, 62 Talbot Ave, Medford, MA, 02155, USA
| | - Ralph R Isberg
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, 150 Harrison Ave., Boston, MA 02111, USA
- Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, 150 Harrison Ave., Boston, MA 02111, USA
| |
Collapse
|
3
|
Aguilera MO, Delgui LR, Reggiori F, Romano PS, Colombo MI. Autophagy as an innate immunity response against pathogens: a Tango dance. FEBS Lett 2024; 598:140-166. [PMID: 38101809 DOI: 10.1002/1873-3468.14788] [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: 08/23/2023] [Revised: 10/18/2023] [Accepted: 10/27/2023] [Indexed: 12/17/2023]
Abstract
Intracellular infections as well as changes in the cell nutritional environment are main events that trigger cellular stress responses. One crucial cell response to stress conditions is autophagy. During the last 30 years, several scenarios involving autophagy induction or inhibition over the course of an intracellular invasion by pathogens have been uncovered. In this review, we will present how this knowledge was gained by studying different microorganisms. We intend to discuss how the cell, via autophagy, tries to repel these attacks with the objective of destroying the intruder, but also how some pathogens have developed strategies to subvert this. These two fates can be compared with a Tango, a dance originated in Buenos Aires, Argentina, in which the partner dancers are in close connection. One of them is the leader, embracing and involving the partner, but the follower may respond escaping from the leader. This joint dance is indeed highly synchronized and controlled, perfectly reflecting the interaction between autophagy and microorganism.
Collapse
Affiliation(s)
- Milton O Aguilera
- Laboratorio de Mecanismos Moleculares Implicados en el Tráfico Vesicular y la Autofagia-Instituto de Histología y Embriología (IHEM), Universidad Nacional de Cuyo, CONICET, Mendoza, Argentina
- Facultad de Odontología, Microbiología, Parasitología e Inmunología, Universidad Nacional de Cuyo, Mendoza, Argentina
| | - Laura R Delgui
- Instituto de Histología y Embriología de Mendoza, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Centro Universitario M5502JMA, Universidad Nacional de Cuyo (UNCuyo), Mendoza, Argentina
- Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Cuyo (UNCuyo), Mendoza, Argentina
| | - Fulvio Reggiori
- Department of Biomedicine, Aarhus University, Denmark
- Aarhus Institute of Advanced Studies (AIAS), Aarhus University, Denmark
| | - Patricia S Romano
- Laboratorio de Biología de Trypanosoma cruzi y la célula hospedadora - Instituto de Histología y Embriología de Mendoza, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Centro Universitario M5502JMA, Universidad Nacional de Cuyo (UNCuyo), Mendoza, Argentina
- Facultad de Ciencias Médicas, Centro Universitario M5502JMA, Universidad Nacional de Cuyo (UNCuyo), Mendoza, Argentina
| | - María I Colombo
- Laboratorio de Mecanismos Moleculares Implicados en el Tráfico Vesicular y la Autofagia-Instituto de Histología y Embriología (IHEM), Universidad Nacional de Cuyo, CONICET, Mendoza, Argentina
- Facultad de Ciencias Médicas, Centro Universitario M5502JMA, Universidad Nacional de Cuyo (UNCuyo), Mendoza, Argentina
| |
Collapse
|
4
|
Isberg R, Kotewicz K, Zheng M, Kim S, Tai A. Sde Proteins Coordinate Ubiquitin Utilization and Phosphoribosylation to Promote Establishment and Maintenance of the Legionella Replication Vacuole. RESEARCH SQUARE 2023:rs.3.rs-3269310. [PMID: 37790456 PMCID: PMC10543313 DOI: 10.21203/rs.3.rs-3269310/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
The Legionella pneumophilaSde family of translocated proteins promote host tubular endoplasmic reticulum (ER) rearrangements that are tightly linked to phosphoribosyl-ubiquitin (pR-Ub) modification of Reticulon 4 (Rtn4). Sde proteins have two additional activities of unclear relevance to the infection process: K63 linkage-specific deubiquitination and phosphoribosyl modification of polyubiquitin (pR-Ub). We show here that the deubiquitination activity (DUB) stimulates ER rearrangements while pR-Ub protects the replication vacuole from cytosolic surveillance by autophagy. Loss of DUB activity was tightly linked to lowered pR-Ub modification of Rtn4, consistent with the DUB activity fueling the production of pR-Ub-Rtn4. In parallel, phosphoribosyl modification of polyUb, in a region of the protein known as the isoleucine patch, caused an absolute block in binding by the autophagy adapter p62. An inability of Sde mutants to modify polyUb resulted in immediate p62 association, a critical precursor to autophagic attack. The ability of Sde WT to block p62 association decayed quickly after bacterial infection, as predicted by the presence of previously characterized L. pneumophila effectors that inactivate Sde and remove polyUb. In sum, these results show that the accessory Sde activities act to stimulate ER rearrangements and protect from host innate immune sensing in a temporal fashion.
Collapse
|
5
|
Ge J, Wang Y, Chen X, Yu K, Luo ZQ, Liu X, Qiu J. Phosphoribosyl-linked serine ubiquitination of USP14 by the SidE family effectors of Legionella excludes p62 from the bacterial phagosome. Cell Rep 2023; 42:112817. [PMID: 37471226 DOI: 10.1016/j.celrep.2023.112817] [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: 11/03/2022] [Revised: 05/19/2023] [Accepted: 06/29/2023] [Indexed: 07/22/2023] Open
Abstract
Xenophagy is an evolutionarily conserved host defensive mechanism to eliminate invading microorganisms through autophagic machinery. The intracellular bacterial pathogen Legionella pneumophila can avoid clearance by the xenophagy pathway via the actions of multiple Dot/Icm effector proteins. Previous studies have shown that p62, an adaptor protein involved in xenophagy signaling, is excluded from Legionella-containing vacuoles (LCVs). Such defects are attributed to the multifunctional SidE family effectors (SidEs) that exhibit classic deubiquitinase (DUB) and phosphoribosyl ubiquitination (PR-ubiquitination) activities, yet the mechanism remains elusive. In the present study, we demonstrate that the host DUB USP14 is PR-ubiquitinated by SidEs at multiple serine residues, which impairs its DUB activity and its interactions with p62. The exclusion of p62 from the bacterial phagosome requires the ubiquitin ligase but not the DUB activity of SidEs. These results reveal that PR-ubiquitination of USP14 by SidEs contributes to the evasion of xenophagic clearance by L. pneumophila.
Collapse
Affiliation(s)
- Jinli Ge
- State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Key Laboratory for Zoonosis Research of the Ministry of Education, College of Veterinary Medicine, Jilin University, Center for Pathogen Biology and Infectious Diseases, The First Hospital of Jilin University, Changchun 130062, China
| | - Ying Wang
- Department of Microbiology and Infectious Disease Center, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Xindi Chen
- State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Key Laboratory for Zoonosis Research of the Ministry of Education, College of Veterinary Medicine, Jilin University, Center for Pathogen Biology and Infectious Diseases, The First Hospital of Jilin University, Changchun 130062, China
| | - Kaiwen Yu
- Department of Microbiology and Infectious Disease Center, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Zhao-Qing Luo
- Purdue Institute for Inflammation, Immunology and Infectious Disease and Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Xiaoyun Liu
- Department of Microbiology and Infectious Disease Center, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China; NHC Key Laboratory of Medical Immunology, Peking University, Beijing 100191, China.
| | - Jiazhang Qiu
- State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Key Laboratory for Zoonosis Research of the Ministry of Education, College of Veterinary Medicine, Jilin University, Center for Pathogen Biology and Infectious Diseases, The First Hospital of Jilin University, Changchun 130062, China.
| |
Collapse
|
6
|
Zhang Q, Wan M, Kudryashova E, Kudryashov DS, Mao Y. Membrane-dependent actin polymerization mediated by the Legionella pneumophila effector protein MavH. PLoS Pathog 2023; 19:e1011512. [PMID: 37463171 PMCID: PMC10381072 DOI: 10.1371/journal.ppat.1011512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 06/26/2023] [Indexed: 07/20/2023] Open
Abstract
L. pneumophila propagates in eukaryotic cells within a specialized niche, the Legionella-containing vacuole (LCV). The infection process is controlled by over 330 effector proteins delivered through the type IV secretion system. In this study, we report that the Legionella MavH effector localizes to endosomes and remodels host actin cytoskeleton in a phosphatidylinositol 3-phosphate (PI(3)P) dependent manner when ectopically expressed. We show that MavH recruits host actin capping protein (CP) and actin to the endosome via its CP-interacting (CPI) motif and WH2-like actin-binding domain, respectively. In vitro assays revealed that MavH stimulates actin assembly on PI(3)P-containing liposomes causing their tubulation. In addition, the recruitment of CP by MavH negatively regulates F-actin density at the membrane. We further show that, in L. pneumophila-infected cells, MavH appears around the LCV at the very early stage of infection and facilitates bacterium entry into the host. Together, our results reveal a novel mechanism of membrane tubulation induced by membrane-dependent actin polymerization catalyzed by MavH that contributes to the early stage of L. pneumophila infection by regulating host actin dynamics.
Collapse
Affiliation(s)
- Qing Zhang
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, New York, United States of America
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, United States of America
| | - Min Wan
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, New York, United States of America
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, United States of America
| | - Elena Kudryashova
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, United States of America
| | - Dmitri S Kudryashov
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, United States of America
| | - Yuxin Mao
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, New York, United States of America
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, United States of America
| |
Collapse
|
7
|
Distel JS, Di Venanzio G, Mackel JJ, Rosen DA, Feldman MF. Replicative Acinetobacter baumannii strains interfere with phagosomal maturation by modulating the vacuolar pH. PLoS Pathog 2023; 19:e1011173. [PMID: 37294840 DOI: 10.1371/journal.ppat.1011173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 05/23/2023] [Indexed: 06/11/2023] Open
Abstract
Bacterial pneumonia is a common infection of the lower respiratory tract that can afflict patients of all ages. Multidrug-resistant strains of Acinetobacter baumannii are increasingly responsible for causing nosocomial pneumonias, thus posing an urgent threat. Alveolar macrophages play a critical role in overcoming respiratory infections caused by this pathogen. Recently, we and others have shown that new clinical isolates of A. baumannii, but not the common lab strain ATCC 19606 (19606), can persist and replicate in macrophages within spacious vacuoles that we called Acinetobacter Containing Vacuoles (ACV). In this work, we demonstrate that the modern A. baumannii clinical isolate 398, but not the lab strain 19606, can infect alveolar macrophages and produce ACVs in vivo in a murine pneumonia model. Both strains initially interact with the alveolar macrophage endocytic pathway, as indicated by EEA1 and LAMP1 markers; however, the fate of these strains diverges at a later stage. While 19606 is eliminated in an autophagy pathway, 398 replicates in ACVs and are not degraded. We show that 398 reverts the natural acidification of the phagosome by secreting large amounts of ammonia, a by-product of amino acid catabolism. We propose that this ability to survive within macrophages may be critical for the persistence of clinical A. baumannii isolates in the lung during a respiratory infection.
Collapse
Affiliation(s)
- Jesus S Distel
- Department of Molecular Microbiology, Washington University School of Medicine, Saint Louis, Missouri, United States of America
| | - Gisela Di Venanzio
- Department of Molecular Microbiology, Washington University School of Medicine, Saint Louis, Missouri, United States of America
| | - Joseph J Mackel
- Department of Pediatrics, Division of Infectious Diseases, Washington University School of Medicine, Saint Louis, Missouri, United States of America
| | - David A Rosen
- Department of Molecular Microbiology, Washington University School of Medicine, Saint Louis, Missouri, United States of America
- Department of Pediatrics, Division of Infectious Diseases, Washington University School of Medicine, Saint Louis, Missouri, United States of America
| | - Mario F Feldman
- Department of Molecular Microbiology, Washington University School of Medicine, Saint Louis, Missouri, United States of America
| |
Collapse
|
8
|
Zhou Y, Hua S, Song L. The versatile defender: exploring the multifaceted role of p62 in intracellular bacterial infection. Front Cell Infect Microbiol 2023; 13:1180708. [PMID: 37216179 PMCID: PMC10196109 DOI: 10.3389/fcimb.2023.1180708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 04/25/2023] [Indexed: 05/24/2023] Open
Abstract
As a highly conserved, multifunctional protein with multiple domains, p62/SQSTM1 plays a crucial role in several essential cellular activities, particularly selective autophagy. Recent research has shown that p62 is crucial in eradicating intracellular bacteria by xenophagy, a selective autophagic process that identifies and eliminates such microorganisms. This review highlights the various roles of p62 in intracellular bacterial infections, including both direct and indirect, antibacterial and infection-promoting aspects, and xenophagy-dependent and independent functions, as documented in published literature. Additionally, the potential applications of synthetic drugs targeting the p62-mediated xenophagy mechanism and unresolved questions about p62's roles in bacterial infections are also discussed.
Collapse
Affiliation(s)
- Yuhao Zhou
- Department of Respiratory Medicine, Center for Pathogen Biology and Infectious Diseases, Key Laboratory of Organ Regeneration and Transplantation of the Ministry of Education, The First Hospital of Jilin University, Changchun, China
- State Key Laboratory for Zoonotic Diseases, The First Hospital of Jilin University, Changchun, China
| | - Shucheng Hua
- Department of Respiratory Medicine, Center for Pathogen Biology and Infectious Diseases, Key Laboratory of Organ Regeneration and Transplantation of the Ministry of Education, The First Hospital of Jilin University, Changchun, China
- State Key Laboratory for Zoonotic Diseases, The First Hospital of Jilin University, Changchun, China
| | - Lei Song
- Department of Respiratory Medicine, Center for Pathogen Biology and Infectious Diseases, Key Laboratory of Organ Regeneration and Transplantation of the Ministry of Education, The First Hospital of Jilin University, Changchun, China
- State Key Laboratory for Zoonotic Diseases, The First Hospital of Jilin University, Changchun, China
| |
Collapse
|
9
|
Shames SR. Eat or Be Eaten: Strategies Used by Legionella to Acquire Host-Derived Nutrients and Evade Lysosomal Degradation. Infect Immun 2023; 91:e0044122. [PMID: 36912646 PMCID: PMC10112212 DOI: 10.1128/iai.00441-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/14/2023] Open
Abstract
To replicate within host cells, bacterial pathogens must acquire host-derived nutrients while avoiding degradative antimicrobial pathways. Fundamental insights into bacterial pathogenicity have been revealed by bacteria of the genus Legionella, which naturally parasitize free-living protozoa by establishing a membrane-bound replicative niche termed the Legionella-containing vacuole (LCV). Biogenesis of the LCV and intracellular replication rely on rapid evasion of the endocytic pathway and acquisition of host-derived nutrients, much of which is mediated by bacterial effector proteins translocated into host cells by a Dot/Icm type IV secretion system. Billions of years of co-evolution with eukaryotic hosts and broad host tropism have resulted in expansion of the Legionella genome to accommodate a massive repertoire of effector proteins that promote LCV biogenesis, safeguard the LCV from endolysosomal maturation, and mediate the acquisition of host nutrients. This minireview is focused on the mechanisms by which an ancient intracellular pathogen leverages effector proteins and hijacks host cell biology to obtain essential host-derived nutrients and prevent lysosomal degradation.
Collapse
Affiliation(s)
- Stephanie R. Shames
- Department of Microbiology & Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| |
Collapse
|
10
|
Klatt AB, Diersing C, Lippmann J, Mayer-Lambertz S, Stegmann F, Fischer S, Caesar S, Fiocca Vernengo F, Hönzke K, Hocke AC, Ruland J, Witzenrath M, Lepenies B, Opitz B. CLEC12A Binds to Legionella pneumophila but Has No Impact on the Host's Antibacterial Response. Int J Mol Sci 2023; 24:ijms24043891. [PMID: 36835297 PMCID: PMC9967056 DOI: 10.3390/ijms24043891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 02/10/2023] [Accepted: 02/12/2023] [Indexed: 02/17/2023] Open
Abstract
Legionella pneumophila is an intracellular pathogen that can cause severe pneumonia after the inhalation of contaminated aerosols and replication in alveolar macrophages. Several pattern recognition receptors (PRRs) have been identified that contribute to the recognition of L. pneumophila by the innate immune system. However, the function of the C-type lectin receptors (CLRs), which are mainly expressed by macrophages and other myeloid cells, remains largely unexplored. Here, we used a library of CLR-Fc fusion proteins to search for CLRs that can bind the bacterium and identified the specific binding of CLEC12A to L. pneumophila. Subsequent infection experiments in human and murine macrophages, however, did not provide evidence for a substantial role of CLEC12A in controlling innate immune responses to the bacterium. Consistently, antibacterial and inflammatory responses to Legionella lung infection were not significantly influenced by CLEC12A deficiency. Collectively, CLEC12A is able to bind to L. pneumophila-derived ligands but does not appear to play a major role in the innate defense against L. pneumophila.
Collapse
Affiliation(s)
- Ann-Brit Klatt
- Department of Infectious Diseases, Respiratory Medicine and Critical Care, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, 13353 Berlin, Germany
| | - Christina Diersing
- Institute for Immunology, University of Veterinary Medicine Hannover, 30559 Hannover, Germany
- Research Center for Emerging Infections and Zoonoses, University of Veterinary Medicine Hannover, 30559 Hannover, Germany
| | - Juliane Lippmann
- Department of Infectious Diseases, Respiratory Medicine and Critical Care, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, 13353 Berlin, Germany
- Max Planck Institute for Infection Biology, Vector Biology, 10117 Berlin, Germany
| | - Sabine Mayer-Lambertz
- Institute for Immunology, University of Veterinary Medicine Hannover, 30559 Hannover, Germany
| | - Felix Stegmann
- Institute for Immunology, University of Veterinary Medicine Hannover, 30559 Hannover, Germany
- Research Center for Emerging Infections and Zoonoses, University of Veterinary Medicine Hannover, 30559 Hannover, Germany
| | - Swantje Fischer
- Institute for Immunology, University of Veterinary Medicine Hannover, 30559 Hannover, Germany
- Research Center for Emerging Infections and Zoonoses, University of Veterinary Medicine Hannover, 30559 Hannover, Germany
| | - Sandra Caesar
- Department of Infectious Diseases, Respiratory Medicine and Critical Care, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, 13353 Berlin, Germany
| | - Facundo Fiocca Vernengo
- Department of Infectious Diseases, Respiratory Medicine and Critical Care, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, 13353 Berlin, Germany
| | - Katja Hönzke
- Department of Infectious Diseases, Respiratory Medicine and Critical Care, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, 13353 Berlin, Germany
- Faculty of Health Sciences Brandenburg, Brandenburg University of Technology Cottbus—Senftenberg, 03046 Cottbus, Germany
| | - Andreas C. Hocke
- Department of Infectious Diseases, Respiratory Medicine and Critical Care, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, 13353 Berlin, Germany
- German Center for Lung Research (DZL), Augustenburger Platz 1, 13353 Berlin, Germany
| | - Jürgen Ruland
- Institute of Clinical Chemistry and Pathobiochemistry, School of Medicine, Technical University of Munich, 80333 Munich, Germany
- Center for Translational Cancer Research (TranslaTUM), 81675 Munich, Germany
- German Cancer Consortium (DKTK), Partner Site Munich, 80336 Munich, Germany
- German Research Center (DKFZ), 69120 Heidelberg, Germany
- German Center for Infection Research (DZIF), Partner Site Munich, 17493 Greifswald, Germany
| | - Martin Witzenrath
- Department of Infectious Diseases, Respiratory Medicine and Critical Care, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, 13353 Berlin, Germany
- German Center for Lung Research (DZL), Augustenburger Platz 1, 13353 Berlin, Germany
| | - Bernd Lepenies
- Institute for Immunology, University of Veterinary Medicine Hannover, 30559 Hannover, Germany
- Research Center for Emerging Infections and Zoonoses, University of Veterinary Medicine Hannover, 30559 Hannover, Germany
- Correspondence: (B.L.); (B.O.)
| | - Bastian Opitz
- Department of Infectious Diseases, Respiratory Medicine and Critical Care, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, 13353 Berlin, Germany
- German Center for Lung Research (DZL), Augustenburger Platz 1, 13353 Berlin, Germany
- Correspondence: (B.L.); (B.O.)
| |
Collapse
|
11
|
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.
Collapse
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)
| |
Collapse
|
12
|
Distel JS, Di Venanzio G, Mackel JJ, Rosen DA, Feldman MF. Replicative Acinetobacter baumannii strains interfere with phagosomal maturation by modulating the vacuolar pH. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.02.526753. [PMID: 36778331 PMCID: PMC9915592 DOI: 10.1101/2023.02.02.526753] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Bacterial pneumonia is a common infection of the lower respiratory tract that can afflict patients of all ages. Multidrug-resistant strains of Acinetobacter baumannii are increasingly responsible for causing nosocomial pneumonias, thus posing an urgent threat. Alveolar macrophages play a critical role in overcoming respiratory infections caused by this pathogen. Recently, we and others have shown that new clinical isolates of A. baumannii , but not the common lab strain ATCC 19606 (19606), can persist and replicate in macrophages within spacious vacuoles that we called A cinetobacter C ontaining V acuoles (ACV). In this work, we demonstrate that the modern A. baumannii clinical isolate 398, but not the lab strain 19606, can infect alveolar macrophages and produce ACVs in vivo in a murine pneumonia model. Both strains initially interact with the alveolar macrophage endocytic pathway, as indicated by EEA1 and LAMP1 markers; however, the fate of these strains diverges at a later stage. While 19606 is eliminated in an autophagy pathway, 398 replicates in ACVs and are not degraded. We show that 398 reverts the natural acidification of the phagosome by secreting large amounts of ammonia, a by-product of amino acid catabolism. We propose that this ability to survive within macrophages may be critical for the persistence of clinical A. baumannii isolates in the lung during a respiratory infection.
Collapse
Affiliation(s)
- Jesus S. Distel
- Department of Molecular Microbiology, Washington University School of Medicine, Saint Louis, Missouri, United States of America
| | - Gisela Di Venanzio
- Department of Molecular Microbiology, Washington University School of Medicine, Saint Louis, Missouri, United States of America
| | - Joseph J. Mackel
- Department of Pediatrics, Division of Infectious Diseases, Washington University School of Medicine, Saint Louis, MO, United States
| | - David A Rosen
- Department of Molecular Microbiology, Washington University School of Medicine, Saint Louis, Missouri, United States of America.,Department of Pediatrics, Division of Infectious Diseases, Washington University School of Medicine, Saint Louis, MO, United States
| | - Mario F. Feldman
- Department of Molecular Microbiology, Washington University School of Medicine, Saint Louis, Missouri, United States of America.,Corresponding author: Mario F. Feldman,
| |
Collapse
|
13
|
Zhang Q, Wan M, Mao Y. Membrane-dependent actin polymerization mediated by the Legionella pneumophila effector protein MavH. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.24.525393. [PMID: 36747622 PMCID: PMC9900769 DOI: 10.1101/2023.01.24.525393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
L. pneumophila propagates in eukaryotic cells within a specialized niche, the Legionella -containing vacuole (LCV). The infection process is controlled by over 330 effector proteins delivered through the type IV secretion system. In this study, we report that the Legionella MavH effector harbors a lipid-binding domain that specifically recognizes PI(3)P (phosphatidylinositol 3-phosphate) and localizes to endosomes when ectopically expressed. We show that MavH recruits host actin capping proteins (CP) and actin to the endosome via its CP interacting (CPI) motif and WH2-like actin-binding domain, respectively. In vitro assays revealed that MavH stimulates robust actin polymerization only in the presence of PI(3)P-containing liposomes and the recruitment of CP by MavH negatively regulates F-actin density at the membrane. Furthermore, in L. pneumophila -infected cells, MavH can be detected around the LCV at the very early stage of infection. Together, our results reveal a novel mechanism of membrane-dependent actin polymerization catalyzed by MavH that may play a role at the early stage of L. pneumophila infection by regulating host actin dynamics.
Collapse
Affiliation(s)
- Qing Zhang
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA.,Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Min Wan
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA.,Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Yuxin Mao
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA.,Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA.,Corresponding Author: , Telephone: 607-255-0783
| |
Collapse
|
14
|
Arunima A, van Schaik EJ, Samuel JE. The emerging roles of long non-coding RNA in host immune response and intracellular bacterial infections. Front Cell Infect Microbiol 2023; 13:1160198. [PMID: 37153158 PMCID: PMC10160451 DOI: 10.3389/fcimb.2023.1160198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Accepted: 04/07/2023] [Indexed: 05/09/2023] Open
Abstract
The long non-coding RNAs (lncRNAs) are evolutionarily conserved classes of non-coding regulatory transcripts of > 200 nucleotides in length. They modulate several transcriptional and post-transcriptional events in the organism. Depending on their cellular localization and interactions, they regulate chromatin function and assembly; and alter the stability and translation of cytoplasmic mRNAs. Although their proposed range of functionality remains controversial, there is increasing research evidence that lncRNAs play a regulatory role in the activation, differentiation and development of immune signaling cascades; microbiome development; and in diseases such as neuronal and cardiovascular disorders; cancer; and pathogenic infections. This review discusses the functional roles of different lncRNAs in regulation of host immune responses, signaling pathways during host-microbe interaction and infection caused by obligate intracellular bacterial pathogens. The study of lncRNAs is assuming significance as it could be exploited for development of alternative therapeutic strategies for the treatment of severe and chronic pathogenic infections caused by Mycobacterium, Chlamydia and Rickettsia infections, as well as commensal colonization. Finally, this review summarizes the translational potential of lncRNA research in development of diagnostic and prognostic tools for human diseases.
Collapse
|
15
|
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.
Collapse
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
| |
Collapse
|
16
|
Tóth D, Horváth GV, Juhász G. The interplay between pathogens and Atg8 family proteins: thousand-faced interactions. FEBS Open Bio 2021; 11:3237-3252. [PMID: 34670023 PMCID: PMC8634866 DOI: 10.1002/2211-5463.13318] [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: 06/29/2021] [Revised: 10/11/2021] [Accepted: 10/19/2021] [Indexed: 01/18/2023] Open
Abstract
Autophagy is an intracellular degradation and recycling process that can also remove pathogenic intracellular bacteria and viruses from within cells (referred to as xenophagy) and activate the adaptive immune responses. But autophagy-especially Atg proteins including Atg8 family members-can also have proviral and probacterial effects. In this review, we summarize known interactions of bacterial, parasitic, and viral proteins with Atg8 family proteins and the outcome of these interactions on pathogen replication, autophagy, or mitophagy. We discuss the value of prediction software and the research methodology in the study of pathogen protein-Atg8 family protein interactions, with selected examples of potential LC3-interacting region motif-containing SARS-CoV-2 proteins.
Collapse
Affiliation(s)
- Dávid Tóth
- Institute of Genetics, Biological Research Centre, Szeged, Hungary
| | - Gábor V Horváth
- Institute of Genetics, Biological Research Centre, Szeged, Hungary
| | - Gábor Juhász
- Institute of Genetics, Biological Research Centre, Szeged, Hungary.,Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, Budapest, Hungary
| |
Collapse
|
17
|
Viana F, Peringathara SS, Rizvi A, Schroeder GN. Host manipulation by bacterial type III and type IV secretion system effector proteases. Cell Microbiol 2021; 23:e13384. [PMID: 34392594 DOI: 10.1111/cmi.13384] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 07/28/2021] [Accepted: 07/30/2021] [Indexed: 01/08/2023]
Abstract
Proteases are powerful enzymes, which cleave peptide bonds, leading most of the time to irreversible fragmentation or degradation of their substrates. Therefore they control many critical cell fate decisions in eukaryotes. Bacterial pathogens exploit this power and deliver protease effectors through specialised secretion systems into host cells. Research over the past years revealed that the functions of protease effectors during infection are diverse, reflecting the lifestyles and adaptations to specific hosts; however, only a small number of peptidase families seem to have given rise to most of these protease virulence factors by the evolution of different substrate-binding specificities, intracellular activation and subcellular targeting mechanisms. Here, we review our current knowledge about the enzymology and function of protease effectors, which Gram-negative bacterial pathogens translocate via type III and IV secretion systems to irreversibly manipulate host processes. We highlight emerging concepts such as signalling by protease cleavage products and effector-triggered immunity, which host cells employ to detect and defend themselves against a protease attack. TAKE AWAY: Proteases irreversibly cleave proteins to control critical cell fate decisions. Gram-negative bacteria use type III and IV secretion systems to inject effectors. Protease effectors are integral weapons for the manipulation of host processes. Effectors evolved from few peptidase families to target diverse substrates. Effector-triggered immunity upon proteolytic attack emerges as host defence.
Collapse
Affiliation(s)
- Flávia Viana
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast, Northern Ireland, UK
| | - Shruthi Sachidanandan Peringathara
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast, Northern Ireland, UK
| | - Arshad Rizvi
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast, Northern Ireland, UK
| | - Gunnar N Schroeder
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast, Northern Ireland, UK
| |
Collapse
|
18
|
Effectors of the Stenotrophomonas maltophilia Type IV Secretion System Mediate Killing of Clinical Isolates of Pseudomonas aeruginosa. mBio 2021; 12:e0150221. [PMID: 34182776 PMCID: PMC8262851 DOI: 10.1128/mbio.01502-21] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Previously, we documented that Stenotrophomonas maltophilia encodes a type IV secretion system (T4SS) that allows the organism to kill, in contact-dependent fashion, heterologous bacteria, including wild-type Pseudomonas aeruginosa. Bioinformatic screens based largely on the presence of both a C-terminal consensus sequence and an adjacent gene encoding a cognate immunity protein identified 13 potential antibacterial effectors, most of which were highly conserved among sequenced strains of S. maltophilia. The immunity proteins of two of these proved especially capable of protecting P. aeruginosa and Escherichia coli against attack from the Stenotrophomonas T4SS. In turn, S. maltophilia mutants lacking the putative effectors RS14245 and RS14255 were impaired for killing not only laboratory E. coli but clinical isolates of P. aeruginosa, including ones isolated from the lungs of cystic fibrosis patients. That complemented mutants behaved as wild type did confirmed that RS14245 and RS14255 are required for the bactericidal activity of the S. maltophilia T4SS. Moreover, a mutant lacking both of these proteins was as impaired as a mutant lacking the T4SS apparatus, indicating that RS14245 and RS14255 account for (nearly) all of the bactericidal effects seen. Utilizing an interbacterial protein translocation assay, we determined that RS14245 and RS14255 are bona fide substrates of the T4SS, a result confirmed by examination of mutants lacking both the T4SS and the individual effectors. Delivery of the cloned 14245 protein (alone) into the periplasm resulted in the killing of target bacteria, indicating that this effector, a putative lipase, is both necessary and sufficient for bactericidal activity.
Collapse
|
19
|
Chauhan D, Shames SR. Pathogenicity and Virulence of Legionella: Intracellular replication and host response. Virulence 2021; 12:1122-1144. [PMID: 33843434 PMCID: PMC8043192 DOI: 10.1080/21505594.2021.1903199] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Bacteria of the genus Legionella are natural pathogens of amoebae that can cause a severe pneumonia in humans called Legionnaires’ Disease. Human disease results from inhalation of Legionella-contaminated aerosols and subsequent bacterial replication within alveolar macrophages. Legionella pathogenicity in humans has resulted from extensive co-evolution with diverse genera of amoebae. To replicate intracellularly, Legionella generates a replication-permissive compartment called the Legionella-containing vacuole (LCV) through the concerted action of hundreds of Dot/Icm-translocated effector proteins. In this review, we present a collective overview of Legionella pathogenicity including infection mechanisms, secretion systems, and translocated effector function. We also discuss innate and adaptive immune responses to L. pneumophila, the implications of Legionella genome diversity and future avenues for the field.
Collapse
Affiliation(s)
- Deepika Chauhan
- Division of Biology, Kansas State University, Manhattan, Kansas, USA
| | | |
Collapse
|
20
|
Autophagy-A Story of Bacteria Interfering with the Host Cell Degradation Machinery. Pathogens 2021; 10:pathogens10020110. [PMID: 33499114 PMCID: PMC7911818 DOI: 10.3390/pathogens10020110] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 01/18/2021] [Accepted: 01/20/2021] [Indexed: 02/07/2023] Open
Abstract
Autophagy is a highly conserved and fundamental cellular process to maintain cellular homeostasis through recycling of defective organelles or proteins. In a response to intracellular pathogens, autophagy further acts as an innate immune response mechanism to eliminate pathogens. This review will discuss recent findings on autophagy as a reaction to intracellular pathogens, such as Salmonella typhimurium, Listeria monocytogenes, Mycobacterium tuberculosis, Staphylococcus aureus, and pathogenic Escherichia coli. Interestingly, while some of these bacteria have developed methods to use autophagy for their own benefit within the cell, others have developed fascinating mechanisms to evade recognition, to subvert the autophagic pathway, or to escape from autophagy.
Collapse
|
21
|
Thomas DR, Newton P, Lau N, Newton HJ. Interfering with Autophagy: The Opposing Strategies Deployed by Legionella pneumophila and Coxiella burnetii Effector Proteins. Front Cell Infect Microbiol 2020; 10:599762. [PMID: 33251162 PMCID: PMC7676224 DOI: 10.3389/fcimb.2020.599762] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 10/13/2020] [Indexed: 12/14/2022] Open
Abstract
Autophagy is a fundamental and highly conserved eukaryotic process, responsible for maintaining cellular homeostasis and releasing nutrients during times of starvation. An increasingly important function of autophagy is its role in the cell autonomous immune response; a process known as xenophagy. Intracellular pathogens are engulfed by autophagosomes and targeted to lysosomes to eliminate the threat to the host cell. To counteract this, many intracellular bacterial pathogens have developed unique approaches to overcome, evade, or co-opt host autophagy to facilitate a successful infection. The intracellular bacteria Legionella pneumophila and Coxiella burnetii are able to avoid destruction by the cell, causing Legionnaires' disease and Q fever, respectively. Despite being related and employing homologous Dot/Icm type 4 secretion systems (T4SS) to translocate effector proteins into the host cell, these pathogens have developed their own unique intracellular niches. L. pneumophila evades the host endocytic pathway and instead forms an ER-derived vacuole, while C. burnetii requires delivery to mature, acidified endosomes which it remodels into a large, replicative vacuole. Throughout infection, L. pneumophila effectors act at multiple points to inhibit recognition by xenophagy receptors and disrupt host autophagy, ensuring it avoids fusion with destructive lysosomes. In contrast, C. burnetii employs its effector cohort to control autophagy, hypothesized to facilitate the delivery of nutrients and membrane to support the growing vacuole and replicating bacteria. In this review we explore the effector proteins that these two organisms utilize to modulate the host autophagy pathway in order to survive and replicate. By better understanding how these pathogens manipulate this highly conserved pathway, we can not only develop better treatments for these important human diseases, but also better understand and control autophagy in the context of human health and disease.
Collapse
Affiliation(s)
| | | | | | - Hayley J. Newton
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, VIC, Australia
| |
Collapse
|