1
|
Resko ZJ, Suhi RF, Thota AV, Kroken AR. Evidence for intracellular Pseudomonas aeruginosa. J Bacteriol 2024; 206:e0010924. [PMID: 38597609 PMCID: PMC11112991 DOI: 10.1128/jb.00109-24] [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] [Indexed: 04/11/2024] Open
Abstract
Pseudomonas aeruginosa is a significant cause of global morbidity and mortality. Although it is often regarded as an extracellular pathogen toward human cells, numerous investigations report its ability to survive and replicate within host cells, and additional studies demonstrate specific mechanisms enabling it to adopt an intracellular lifestyle. This ability of P. aeruginosa remains less well-investigated than that of other intracellular bacteria, although it is currently gaining attention. If intracellular bacteria are not killed after entering host cells, they may instead receive protection from immune recognition and experience reduced exposure to antibiotic therapy, among additional potential advantages shared with other facultative intracellular pathogens. For this review, we compiled studies that observe intracellular P. aeruginosa across strains, cell types, and experimental systems in vitro, as well as contextualize these findings with the few studies that report similar observations in vivo. We also seek to address key findings that drove the perception that P. aeruginosa remains extracellular in order to reconcile what is currently understood about intracellular pathogenesis and highlight open questions regarding its contribution to disease.
Collapse
Affiliation(s)
- Zachary J. Resko
- Department of Microbiology and Immunology, Loyola University Chicago, Maywood, Illinois, USA
| | - Rachel F. Suhi
- Department of Microbiology and Immunology, Loyola University Chicago, Maywood, Illinois, USA
| | - Adam V. Thota
- Department of Microbiology and Immunology, Loyola University Chicago, Maywood, Illinois, USA
| | - Abby R. Kroken
- Department of Microbiology and Immunology, Loyola University Chicago, Maywood, Illinois, USA
| |
Collapse
|
2
|
Minns MS, Liboro K, Lima TS, Abbondante S, Miller BA, Marshall ME, Tran Chau J, Roistacher A, Rietsch A, Dubyak GR, Pearlman E. NLRP3 selectively drives IL-1β secretion by Pseudomonas aeruginosa infected neutrophils and regulates corneal disease severity. Nat Commun 2023; 14:5832. [PMID: 37730693 PMCID: PMC10511713 DOI: 10.1038/s41467-023-41391-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 09/01/2023] [Indexed: 09/22/2023] Open
Abstract
Macrophages infected with Gram-negative bacteria expressing Type III secretion system (T3SS) activate the NLRC4 inflammasome, resulting in Gasdermin D (GSDMD)-dependent, but GSDME independent IL-1β secretion and pyroptosis. Here we examine inflammasome signaling in neutrophils infected with Pseudomonas aeruginosa strain PAO1 that expresses the T3SS effectors ExoS and ExoT. IL-1β secretion by neutrophils requires the T3SS needle and translocon proteins and GSDMD. In macrophages, PAO1 and mutants lacking ExoS and ExoT (ΔexoST) require NLRC4 for IL-1β secretion. While IL-1β release from ΔexoST infected neutrophils is also NLRC4-dependent, infection with PAO1 is instead NLRP3-dependent and driven by the ADP ribosyl transferase activity of ExoS. Genetic and pharmacologic approaches using MCC950 reveal that NLRP3 is also essential for bacterial killing and disease severity in a murine model of P. aeruginosa corneal infection (keratitis). Overall, these findings reveal a function for ExoS ADPRT in regulating inflammasome subtype usage in neutrophils versus macrophages and an unexpected role for NLRP3 in P. aeruginosa keratitis.
Collapse
Affiliation(s)
- Martin S Minns
- Departments of Ophthalmology and Physiology & Biophysics, University of California, Irvine, CA, USA
- Odyssey Therapeutics, Boston, MA, USA
| | - Karl Liboro
- Departments of Ophthalmology and Physiology & Biophysics, University of California, Irvine, CA, USA
| | - Tatiane S Lima
- Departments of Ophthalmology and Physiology & Biophysics, University of California, Irvine, CA, USA
- Department of Biological Sciences, California State Polytechnic University, Pomona, CA, USA
| | - Serena Abbondante
- Departments of Ophthalmology and Physiology & Biophysics, University of California, Irvine, CA, USA
| | - Brandon A Miller
- Department of Physiology & Biophysics, Case Western Reserve University, Cleveland, OH, USA
| | - Michaela E Marshall
- Departments of Ophthalmology and Physiology & Biophysics, University of California, Irvine, CA, USA
| | - Jolynn Tran Chau
- Departments of Ophthalmology and Physiology & Biophysics, University of California, Irvine, CA, USA
| | - Alicia Roistacher
- Department of Molecular Biology and Microbiology, Case Western Reserve University, Cleveland, OH, USA
| | - Arne Rietsch
- Department of Molecular Biology and Microbiology, Case Western Reserve University, Cleveland, OH, USA
| | - George R Dubyak
- Department of Physiology & Biophysics, Case Western Reserve University, Cleveland, OH, USA
| | - Eric Pearlman
- Departments of Ophthalmology and Physiology & Biophysics, University of California, Irvine, CA, USA.
| |
Collapse
|
3
|
Kharga K, Kumar L, Patel SKS. Recent Advances in Monoclonal Antibody-Based Approaches in the Management of Bacterial Sepsis. Biomedicines 2023; 11:biomedicines11030765. [PMID: 36979744 PMCID: PMC10045367 DOI: 10.3390/biomedicines11030765] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 02/21/2023] [Accepted: 02/27/2023] [Indexed: 03/06/2023] Open
Abstract
Sepsis is a life-threatening condition characterized by an uncontrolled inflammatory response to an infectious agent and its antigens. Immune cell activation against the antigens causes severe distress that mediates a strong inflammatory response in vital organs. Sepsis is responsible for a high rate of morbidity and mortality in immunosuppressed patients. Monoclonal antibody (mAb)-based therapeutic strategies are now being explored as a viable therapy option for severe sepsis and septic shock. Monoclonal antibodies may provide benefits through two major strategies: (a) monoclonal antibodies targeting the pathogen and its components, and (b) mAbs targeting inflammatory signaling may directly suppress the production of inflammatory mediators. The major focus of mAb therapies has been bacterial endotoxin (lipopolysaccharide), although other surface antigens are also being investigated for mAb therapy. Several promising candidates for mAbs are undergoing clinical trials at present. Despite several failures and the investigation of novel targets, mAb therapy provides a glimmer of hope for the treatment of severe bacterial sepsis and septic shock. In this review, mAb candidates, their efficacy against controlling infection, with special emphasis on potential roadblocks, and prospects are discussed.
Collapse
Affiliation(s)
- Kusum Kharga
- School of Biotechnology, Faculty of Applied Sciences and Biotechnology, Shoolini University, Solan 173229, Himachal Pradesh, India
| | - Lokender Kumar
- School of Biotechnology, Faculty of Applied Sciences and Biotechnology, Shoolini University, Solan 173229, Himachal Pradesh, India
- Cancer Biology Laboratory, Raj Khosla Centre for Cancer Research, Shoolini University, Solan 173229, Himachal Pradesh, India
- Correspondence: (L.K.); (S.K.S.P.)
| | - Sanjay Kumar Singh Patel
- Department of Chemical Engineering, Konkuk University, Seoul 05029, Republic of Korea
- Correspondence: (L.K.); (S.K.S.P.)
| |
Collapse
|
4
|
Chen P, Goldberg MB. Recent insights into type-3 secretion system injectisome structure and mechanism of human enteric pathogens. Curr Opin Microbiol 2023; 71:102232. [PMID: 36368294 PMCID: PMC10510281 DOI: 10.1016/j.mib.2022.102232] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 10/06/2022] [Accepted: 10/19/2022] [Indexed: 11/10/2022]
Abstract
Type-3 secretion system injectisomes are multiprotein complexes that translocate bacterial effector proteins from the cytoplasm of gram-negative bacteria directly into the cytosol of eukaryotic host cells. These systems are present in more than 30 bacterial species, including numerous human, animal, and plant pathogens. We review recent discoveries of structural and molecular mechanisms of effector protein translocation through the injectisomes and recent advances in the understanding of mechanisms of activation of effector protein secretion.
Collapse
Affiliation(s)
- Poyin Chen
- Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, Boston, MA, USA; Department of Microbiology, Harvard Medical School, Boston, MA, USA
| | - Marcia B Goldberg
- Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, Boston, MA, USA; Department of Microbiology, Harvard Medical School, Boston, MA, USA; Broad Institute, Cambridge, MA, USA.
| |
Collapse
|
5
|
PopB-PcrV Interactions Are Essential for Pore Formation in the Pseudomonas aeruginosa Type III Secretion System Translocon. mBio 2022; 13:e0238122. [PMID: 36154276 PMCID: PMC9600203 DOI: 10.1128/mbio.02381-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The type III secretion system (T3SS) is a syringe-like virulence factor that delivers bacterial proteins directly into the cytoplasm of host cells. An essential component of the system is the translocon, which creates a pore in the host cell membrane through which proteins are injected. In Pseudomonas aeruginosa, the translocation pore is formed by proteins PopB and PopD and attaches to the T3SS needle via the needle tip protein PcrV. The structure and stoichiometry of the multimeric pore are unknown. We took a genetic approach to map contact points within the system by taking advantage of the fact that the translocator proteins of P. aeruginosa and the related Aeromonas hydrophila T3SS are incompatible and cannot be freely exchanged. We created chimeric versions of P. aeruginosa PopB and A. hydrophila AopB to intentionally disrupt and restore protein-protein interactions. We identified a chimeric B-translocator that specifically disrupts an interaction with the needle tip protein. This disruption did not affect membrane insertion of the B-translocator but did prevent formation of the translocation pore, arguing that the needle tip protein drives the formation of the translocation pore. IMPORTANCE Type III secretion systems are integral to the pathogenesis of many Gram-negative bacterial pathogens. A hallmark of these secretion systems is that they deliver effector proteins vectorially into the targeted host cell via a translocation pore. The translocon is crucial for T3SS function, but it has proven difficult to study biochemically and structurally. Here, we used a genetic approach to identify protein-protein contacts among translocator proteins that are important for function. This genetic approach allowed us to specifically break a contact between the translocator PopB and the T3SS needle tip protein PcrV. Breaking this contact allowed us to determine, for the first time, that the needle tip actively participates in the assembly of the translocation pore by the membrane-bound pore-forming translocator proteins. Our study therefore both expands our knowledge of the network of functionally important interactions among translocator proteins and illuminates a new step in the assembly of this critical host cell interface.
Collapse
|
6
|
Jurado-Martín I, Sainz-Mejías M, McClean S. Pseudomonas aeruginosa: An Audacious Pathogen with an Adaptable Arsenal of Virulence Factors. Int J Mol Sci 2021; 22:3128. [PMID: 33803907 PMCID: PMC8003266 DOI: 10.3390/ijms22063128] [Citation(s) in RCA: 236] [Impact Index Per Article: 78.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Revised: 03/16/2021] [Accepted: 03/16/2021] [Indexed: 12/13/2022] Open
Abstract
Pseudomonas aeruginosa is a dominant pathogen in people with cystic fibrosis (CF) contributing to morbidity and mortality. Its tremendous ability to adapt greatly facilitates its capacity to cause chronic infections. The adaptability and flexibility of the pathogen are afforded by the extensive number of virulence factors it has at its disposal, providing P. aeruginosa with the facility to tailor its response against the different stressors in the environment. A deep understanding of these virulence mechanisms is crucial for the design of therapeutic strategies and vaccines against this multi-resistant pathogen. Therefore, this review describes the main virulence factors of P. aeruginosa and the adaptations it undergoes to persist in hostile environments such as the CF respiratory tract. The very large P. aeruginosa genome (5 to 7 MB) contributes considerably to its adaptive capacity; consequently, genomic studies have provided significant insights into elucidating P. aeruginosa evolution and its interactions with the host throughout the course of infection.
Collapse
Affiliation(s)
| | | | - Siobhán McClean
- School of Biomolecular and Biomedical Sciences, University College Dublin, Belfield, Dublin 4 D04 V1W8, Ireland; (I.J.-M.); (M.S.-M.)
| |
Collapse
|