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Schlichter Kadosh Y, Muthuraman S, Nisaa K, Ben-Zvi A, Karsagi Byron DL, Shagan M, Brandis A, Mehlman T, Gopas J, Saravana Kumar R, Kushmaro A. Pseudomonas aeruginosa quorum sensing and biofilm attenuation by a di-hydroxy derivative of piperlongumine (PL-18). Biofilm 2024; 8:100215. [PMID: 39148892 PMCID: PMC11326495 DOI: 10.1016/j.bioflm.2024.100215] [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: 01/10/2024] [Revised: 07/01/2024] [Accepted: 07/13/2024] [Indexed: 08/17/2024] Open
Abstract
Bacterial communication, Quorum Sensing (QS), is a target against virulence and prevention of antibiotic-resistant infections. 16 derivatives of Piperlongumine (PL), an amide alkaloid from Piper longum L., were screened for QS inhibition. PL-18 had the best QSI activity. PL-18 inhibited the lasR-lasI, rhlR-rhlI, and pqs QS systems of Pseudomonas aeruginosa. PL-18 inhibited pyocyanin and rhamnolipids that are QS-controlled virulence elements. Iron is an essential element for pathogenicity, biofilm formation and resilience in harsh environments, its uptake was inhibited by PL-18. Pl-18 significantly reduced the biofilm biovolume including in established biofilms. PL-18-coated silicon tubes significantly inhibited biofilm formation. The transcriptome study of treated P. aeruginosa showed that PL-18 indeed reduced the expression of QS and iron homeostasis related genes, and up regulated sulfur metabolism related genes. Altogether, PL-18 inhibits QS, virulence, iron uptake, and biofilm formation. Thus, PL-18 should be further developed against bacterial infection, antibiotic resistance, and biofilm formation.
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Affiliation(s)
- Yael Schlichter Kadosh
- Avram and Stella Goldstein-Goren Department of Biotechnology Engineering, Ben Gurion University of the Negev, Beer Sheva, Israel
| | | | - Khairun Nisaa
- Department of Life Science, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Anat Ben-Zvi
- Department of Life Science, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Danit Lisa Karsagi Byron
- Department of Civil and Environmental Engineering, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Marilou Shagan
- Avram and Stella Goldstein-Goren Department of Biotechnology Engineering, Ben Gurion University of the Negev, Beer Sheva, Israel
| | - Alexander Brandis
- Department of Life Sciences Core Facilities, Weizmann Institute of Science, Rehovot, Israel
| | - Tevie Mehlman
- Department of Life Sciences Core Facilities, Weizmann Institute of Science, Rehovot, Israel
| | - Jacob Gopas
- Department of Microbiology, Immunology and Genetics Faculty of Health Sciences, Ben Gurion University of the Negev, Beer Sheva, Israel
| | | | - Ariel Kushmaro
- Avram and Stella Goldstein-Goren Department of Biotechnology Engineering, Ben Gurion University of the Negev, Beer Sheva, Israel
- The Ilse Katz Center for Nanoscale Science and Technology, Ben Gurion University of the Negev, Beer Sheva, Israel
- School of Sustainability and Climate Change, Ben Gurion University of the Negev, Beer Sheva, Israel
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Ma X, Zeng J, Xiao W, Li W, Cheng J, Lin J. Relationship between Pyochelin and Pseudomonas Quinolone Signal in Pseudomonas aeruginosa: A Direction for Future Research. Int J Mol Sci 2024; 25:8611. [PMID: 39201297 PMCID: PMC11354437 DOI: 10.3390/ijms25168611] [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: 06/29/2024] [Revised: 08/03/2024] [Accepted: 08/06/2024] [Indexed: 09/02/2024] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that requires iron to survive in the host; however, the host immune system limits the availability of iron. Pyochelin (PCH) is a major siderophore produced by P. aeruginosa during infection, which can help P. aeruginosa survive in an iron-restricted environment and cause infection. The infection activity of P. aeruginosa is regulated by the Pseudomonas quinolone signal (PQS) quorum-sensing system. The system uses 2-heptyl-3-hydroxy-4-quinolone (PQS) or its precursor, 2-heptyl-4-quinolone (HHQ), as the signal molecule. PQS can control specific life processes such as mediating quorum sensing, cytotoxicity, and iron acquisition. This review summarizes the biosynthesis of PCH and PQS, the shared transport system of PCH and PQS, and the regulatory relationship between PCH and PQS. The correlation between the PQS and PCH is emphasized to provide a new direction for future research.
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Affiliation(s)
| | | | | | | | - Juanli Cheng
- Shaanxi Key Laboratory of Chinese Jujube, College of Life Sciences, Yan’an University, Yan’an 716000, China; (X.M.); (J.Z.); (W.X.); (W.L.)
| | - Jinshui Lin
- Shaanxi Key Laboratory of Chinese Jujube, College of Life Sciences, Yan’an University, Yan’an 716000, China; (X.M.); (J.Z.); (W.X.); (W.L.)
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Vieira TF, Leitão MM, Cerqueira NMFSA, Sousa SF, Borges A, Simões M. Montelukast and cefoperazone act as antiquorum sensing and antibiofilm agents against Pseudomonas aeruginosa. J Appl Microbiol 2024; 135:lxae088. [PMID: 38587815 DOI: 10.1093/jambio/lxae088] [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: 01/02/2024] [Revised: 03/21/2024] [Accepted: 04/03/2024] [Indexed: 04/09/2024]
Abstract
AIMS Drug repurposing is an attractive strategy to control biofilm-related infectious diseases. In this study, two drugs (montelukast and cefoperazone) with well-established therapeutic applications were tested on Pseudomonas aeruginosa quorum sensing (QS) inhibition and biofilm control. METHODS AND RESULTS The activity of montelukast and cefoperazone was evaluated for Pqs signal inhibition, pyocyanin synthesis, and prevention and eradication of Ps. aeruginosa biofilms. Cefoperazone inhibited the Pqs system by hindering the production of the autoinducer molecules 2-heptyl-4-hydroxyquinoline (HHQ) and 2-heptyl-3-hydroxy-4(1H)-quinolone (the Pseudomonas quinolone signal or PQS), corroborating in silico results. Pseudomonas aeruginosa pyocyanin production was reduced by 50%. The combination of the antibiotics cefoperazone and ciprofloxacin was synergistic for Ps. aeruginosa biofilm control. On the other hand, montelukast had no relevant effects on the inhibition of the Pqs system and against Ps. aeruginosa biofilm. CONCLUSION This study provides for the first time strong evidence that cefoperazone interacts with the Pqs system, hindering the formation of the autoinducer molecules HHQ and PQS, reducing Ps. aeruginosa pathogenicity and virulence. Cefoperazone demonstrated a potential to be used in combination with less effective antibiotics (e.g. ciprofloxacin) to potentiate the biofilm control action.
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Affiliation(s)
- Tatiana F Vieira
- Faculty of Medicine, LAQV/REQUIMTE, BioSIM, Departamento de Medicina, University of Porto, Alameda Prof. Hernâni Monteiro, 4200-319 Porto, Portugal
| | - Miguel M Leitão
- Faculty of Engineering, LEPABE Laboratory for Process Engineering, Environment, Biotechnology and Energy, University of Porto, Rua Dr Roberto Frias, s/n, 4200-465 Porto, Portugal
- Faculty of Engineering, ALiCE - Associate Laboratory in Chemical Engineering, University of Porto, Rua Dr Roberto Frias, 4200-465 Porto, Portugal
- Faculty of Sciences, CIQUP-IMS - Department of Chemistry and Biochemistry, University of Porto, Rua Campo Alegre 687, 4169-007 Porto, Portugal
| | - Nuno M F S A Cerqueira
- Faculty of Medicine, LAQV/REQUIMTE, BioSIM, Departamento de Medicina, University of Porto, Alameda Prof. Hernâni Monteiro, 4200-319 Porto, Portugal
| | - Sérgio F Sousa
- Faculty of Medicine, LAQV/REQUIMTE, BioSIM, Departamento de Medicina, University of Porto, Alameda Prof. Hernâni Monteiro, 4200-319 Porto, Portugal
| | - Anabela Borges
- Faculty of Engineering, LEPABE Laboratory for Process Engineering, Environment, Biotechnology and Energy, University of Porto, Rua Dr Roberto Frias, s/n, 4200-465 Porto, Portugal
- Faculty of Engineering, ALiCE - Associate Laboratory in Chemical Engineering, University of Porto, Rua Dr Roberto Frias, 4200-465 Porto, Portugal
| | - Manuel Simões
- Faculty of Engineering, LEPABE Laboratory for Process Engineering, Environment, Biotechnology and Energy, University of Porto, Rua Dr Roberto Frias, s/n, 4200-465 Porto, Portugal
- Faculty of Engineering, ALiCE - Associate Laboratory in Chemical Engineering, University of Porto, Rua Dr Roberto Frias, 4200-465 Porto, Portugal
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de Anda J, Kuchma SL, Webster SS, Boromand A, Lewis KA, Lee CK, Contreras M, Medeiros Pereira VF, Schmidt W, Hogan DA, O’Hern CS, O’Toole GA, Wong GCL. How P. aeruginosa cells with diverse stator composition collectively swarm. mBio 2024; 15:e0332223. [PMID: 38426789 PMCID: PMC11005332 DOI: 10.1128/mbio.03322-23] [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: 12/11/2023] [Accepted: 12/20/2023] [Indexed: 03/02/2024] Open
Abstract
Swarming is a macroscopic phenomenon in which surface bacteria organize into a motile population. The flagellar motor that drives swarming in Pseudomonas aeruginosa is powered by stators MotAB and MotCD. Deletion of the MotCD stator eliminates swarming, whereas deletion of the MotAB stator enhances swarming. Interestingly, we measured a strongly asymmetric stator availability in the wild-type (WT) strain, with MotAB stators produced at an approximately 40-fold higher level than MotCD stators. However, utilization of MotCD stators in free swimming cells requires higher liquid viscosities, while MotAB stators are readily utilized at low viscosities. Importantly, we find that cells with MotCD stators are ~10× more likely to have an active motor compared to cells uses the MotAB stators. The spectrum of motility intermittency can either cooperatively shut down or promote flagellum motility in WT populations. In P. aeruginosa, transition from a static solid-like biofilm to a dynamic liquid-like swarm is not achieved at a single critical value of flagellum torque or stator fraction but is collectively controlled by diverse combinations of flagellum activities and motor intermittencies via dynamic stator utilization. Experimental and computational results indicate that the initiation or arrest of flagellum-driven swarming motility does not occur from individual fitness or motility performance but rather related to concepts from the "jamming transition" in active granular matter.IMPORTANCEIt is now known that there exist multifactorial influences on swarming motility for P. aeruginosa, but it is not clear precisely why stator selection in the flagellum motor is so important. We show differential production and utilization of the stators. Moreover, we find the unanticipated result that the two motor configurations have significantly different motor intermittencies: the fraction of flagellum-active cells in a population on average with MotCD is active ~10× more often than with MotAB. What emerges from this complex landscape of stator utilization and resultant motor output is an intrinsically heterogeneous population of motile cells. We show how consequences of stator recruitment led to swarming motility and how the stators potentially relate to surface sensing circuitry.
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Affiliation(s)
- Jaime de Anda
- Department of Bioengineering, University of California Los Angeles, Los Angeles, California, USA
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California, USA
- Department of Microbiology, Immunology & Molecular Genetics, University of California Los Angeles, Los Angeles, California, USA
- California NanoSystems Institute, University of California Los Angeles, Los Angeles, California, USA
| | - Sherry L. Kuchma
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Shanice S. Webster
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Arman Boromand
- Department of Mechanical Engineering & Materials Science, Yale University, New Haven, Connecticut, USA
| | - Kimberley A. Lewis
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Calvin K. Lee
- Department of Bioengineering, University of California Los Angeles, Los Angeles, California, USA
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California, USA
- Department of Microbiology, Immunology & Molecular Genetics, University of California Los Angeles, Los Angeles, California, USA
- California NanoSystems Institute, University of California Los Angeles, Los Angeles, California, USA
| | - Maria Contreras
- Department of Bioengineering, University of California Los Angeles, Los Angeles, California, USA
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California, USA
- Department of Microbiology, Immunology & Molecular Genetics, University of California Los Angeles, Los Angeles, California, USA
- California NanoSystems Institute, University of California Los Angeles, Los Angeles, California, USA
| | | | - William Schmidt
- Department of Bioengineering, University of California Los Angeles, Los Angeles, California, USA
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California, USA
- Department of Microbiology, Immunology & Molecular Genetics, University of California Los Angeles, Los Angeles, California, USA
- California NanoSystems Institute, University of California Los Angeles, Los Angeles, California, USA
| | - Deborah A. Hogan
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Corey S. O’Hern
- Department of Mechanical Engineering & Materials Science, Yale University, New Haven, Connecticut, USA
| | - George A. O’Toole
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Gerard C. L. Wong
- Department of Bioengineering, University of California Los Angeles, Los Angeles, California, USA
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California, USA
- Department of Microbiology, Immunology & Molecular Genetics, University of California Los Angeles, Los Angeles, California, USA
- California NanoSystems Institute, University of California Los Angeles, Los Angeles, California, USA
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Fallah S, Duncan D, Reichl KD, Smith MJ, Wang W, Porco JA, Brown LE, Whitesell L, Robbins N, Cowen LE. A chemical screen identifies structurally diverse metal chelators with activity against the fungal pathogen Candida albicans. Microbiol Spectr 2024; 12:e0409523. [PMID: 38376363 PMCID: PMC10986608 DOI: 10.1128/spectrum.04095-23] [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: 12/02/2023] [Accepted: 01/25/2024] [Indexed: 02/21/2024] Open
Abstract
Candida albicans, one of the most prevalent human fungal pathogens, causes diverse diseases extending from superficial infections to deadly systemic mycoses. Currently, only three major classes of antifungal drugs are available to treat systemic infections: azoles, polyenes, and echinocandins. Alarmingly, the efficacy of these antifungals against C. albicans is hindered both by basal tolerance toward the drugs and the development of resistance mechanisms such as alterations of the drug's target, modulation of stress responses, and overexpression of efflux pumps. Thus, the need to identify novel antifungal strategies is dire. To address this challenge, we screened 3,049 structurally-diverse compounds from the Boston University Center for Molecular Discovery (BU-CMD) chemical library against a C. albicans clinical isolate and identified 17 molecules that inhibited C. albicans growth by >80% relative to controls. Among the most potent compounds were CMLD013360, CMLD012661, and CMLD012693, molecules representing two distinct chemical scaffolds, including 3-hydroxyquinolinones and a xanthone natural product. Based on structural insights, CMLD013360, CMLD012661, and CMLD012693 were hypothesized to exert antifungal activity through metal chelation. Follow-up investigations revealed all three compounds exerted antifungal activity against non-albicans Candida, including Candida auris and Candida glabrata, with the xanthone natural product CMLD013360 also displaying activity against the pathogenic mould Aspergillus fumigatus. Media supplementation with metallonutrients, namely ferric or ferrous iron, rescued C. albicans growth, confirming these compounds act as metal chelators. Thus, this work identifies and characterizes two chemical scaffolds that chelate iron to inhibit the growth of the clinically relevant fungal pathogen C. albicansIMPORTANCEThe worldwide incidence of invasive fungal infections is increasing at an alarming rate. Systemic candidiasis caused by the opportunistic pathogen Candida albicans is the most common cause of life-threatening fungal infection. However, due to the limited number of antifungal drug classes available and the rise of antifungal resistance, an urgent need exists for the identification of novel treatments. By screening a compound collection from the Boston University Center for Molecular Discovery (BU-CMD), we identified three compounds representing two distinct chemical scaffolds that displayed activity against C. albicans. Follow-up analyses confirmed these molecules were also active against other pathogenic fungal species including Candida auris and Aspergillus fumigatus. Finally, we determined that these compounds inhibit the growth of C. albicans in culture through iron chelation. Overall, this observation describes two novel chemical scaffolds with antifungal activity against diverse fungal pathogens.
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Affiliation(s)
- Sara Fallah
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Dustin Duncan
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- Department of Chemistry, Brock University, St. Catharines, Ontario, Canada
| | - Kyle D. Reichl
- Department of Chemistry, Center for Molecular Discovery (BU-CMD), Boston University, Boston, Massachusetts, USA
| | - Michael J. Smith
- Department of Chemistry, Center for Molecular Discovery (BU-CMD), Boston University, Boston, Massachusetts, USA
| | - Wenyu Wang
- Department of Chemistry, Center for Molecular Discovery (BU-CMD), Boston University, Boston, Massachusetts, USA
| | - John A. Porco
- Department of Chemistry, Center for Molecular Discovery (BU-CMD), Boston University, Boston, Massachusetts, USA
| | - Lauren E. Brown
- Department of Chemistry, Center for Molecular Discovery (BU-CMD), Boston University, Boston, Massachusetts, USA
| | - Luke Whitesell
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Nicole Robbins
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Leah E. Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
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Shahzad S, Krug SA, Mouriño S, Huang W, Kane MA, Wilks A. Pseudomonas aeruginosa heme metabolites biliverdin IXβ and IXδ are integral to lifestyle adaptations associated with chronic infection. mBio 2024; 15:e0276323. [PMID: 38319089 PMCID: PMC10936436 DOI: 10.1128/mbio.02763-23] [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: 10/11/2023] [Accepted: 12/11/2023] [Indexed: 02/07/2024] Open
Abstract
Pseudomonas aeruginosa is a versatile opportunistic pathogen requiring iron for its survival and virulence within the host. The ability to switch to heme as an iron source and away from siderophore uptake provides an advantage in chronic infection. We have recently shown the extracellular heme metabolites biliverdin IXβ (BVIXβ) and BVIXδ positively regulate the heme-dependent cell surface signaling cascade. We further investigated the role of BVIXβ and BVIXδ in cell signaling utilizing allelic strains lacking a functional heme oxygenase (hemOin) or one reengineered to produce BVIXα (hemOα). Compared to PAO1, both strains show a heme-dependent growth defect, decreased swarming and twitching, and less robust biofilm formation. Interestingly, the motility and biofilm defects were partially rescued on addition of exogenous BVIXβ and BVIXδ. Utilizing liquid chromatography-tandem mass spectrometry, we performed a comparative proteomics and metabolomics analysis of PAO1 versus the allelic strains in shaking and static conditions. In shaking conditions, the hemO allelic strains showed a significant increase in proteins involved in quorum sensing, phenazine production, and chemotaxis. Metabolite profiling further revealed increased levels of Pseudomonas quinolone signal and phenazine metabolites. In static conditions, we observed a significant repression of chemosensory pathways and type IV pili biogenesis proteins as well as several phosphodiesterases associated with biofilm dispersal. We propose BVIX metabolites function as signaling and chemotactic molecules integrating heme utilization as an iron source into the adaptation of P. aeruginosa from a planktonic to sessile lifestyle. IMPORTANCE The opportunistic pathogen Pseudomonas aeruginosa causes long-term chronic infection in the airways of cystic fibrosis patients. The ability to scavenge iron and to establish chronic infection within this environment coincides with a switch to utilize heme as the primary iron source. Herein, we show the heme metabolites biliverdin beta and delta are themselves important signaling molecules integrating the switch in iron acquisition systems with cooperative behaviors such as motility and biofilm formation that are essential for long-term chronic infection. These significant findings will enhance the development of viable multi-targeted therapeutics effective against both heme utilization and cooperative behaviors essential for survival and persistence within the host.
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Affiliation(s)
- Saba Shahzad
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland, USA
| | - Samuel A. Krug
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland, USA
| | - Susana Mouriño
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland, USA
| | - Weiliang Huang
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland, USA
| | - Maureen A. Kane
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland, USA
| | - Angela Wilks
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland, USA
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Hills OJ, Noble IO, Heyam A, Scott AJ, Smith J, Chappell HF. Atomistic modelling and NMR studies reveal that gallium can target the ferric PQS uptake system in P. aeruginosa biofilms. MICROBIOLOGY (READING, ENGLAND) 2023; 169:001422. [PMID: 38117289 PMCID: PMC10765035 DOI: 10.1099/mic.0.001422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Accepted: 12/11/2023] [Indexed: 12/21/2023]
Abstract
Intravenous gallium nitrate therapy is a novel therapeutic strategy deployed to combat chronic Pseudomonas aeruginosa biofilm infections in the lungs of cystic fibrosis (CF) patients by interfering with iron (Fe3+) uptake. The therapy is a source of Ga3+, which competes with Fe3+ for siderophore binding, subsequently disrupting iron metabolism and inhibiting biofilm proliferation in vivo. It was recently demonstrated that the Pseudomonas quinolone signal (PQS) can chelate Fe3+ to assist in bacterial iron uptake. However, it is unknown whether exogenous gallium also targets [Fe(PQS)3] uptake, which, in turn, would extend the mechanism of gallium therapy beyond siderophore competition, potentially supporting use of the therapy against P. aeruginosa mutants deficient in siderophore uptake proteins. To that end, the thermodynamic feasibility of iron-for-gallium cation exchange into [Fe(PQS)3] was evaluated using quantum chemical density functional theory (DFT) modelling and verified experimentally using 1H nuclear magnetic resonance (NMR). We demonstrate here that Ga3+ can strongly bind to three PQS molecules and, furthermore, displace and substitute Fe3+ from the native chelate pocket within PQS complexes, through a Trojan horse mechanism, retaining the key structural features present within the native ferric complex. As such, [Fe(PQS)3] complexes, in addition to ferric-siderophore complexes, represent another target for gallium therapy.
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Affiliation(s)
- Oliver J. Hills
- School of Food Science and Nutrition, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK
| | - Isaac O.K. Noble
- School of Food Science and Nutrition, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK
| | - Alex Heyam
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK
| | - Andrew J. Scott
- School of Chemical and Process Engineering, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK
| | - James Smith
- School of Food Science and Nutrition, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK
| | - Helen F. Chappell
- School of Food Science and Nutrition, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK
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8
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Niggli S, Schwyter L, Poveda L, Grossmann J, Kümmerli R. Rapid and strain-specific resistance evolution of Staphylococcus aureus against inhibitory molecules secreted by Pseudomonas aeruginosa. mBio 2023; 14:e0315322. [PMID: 37646506 PMCID: PMC10653847 DOI: 10.1128/mbio.03153-22] [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: 11/10/2022] [Accepted: 06/30/2023] [Indexed: 09/01/2023] Open
Abstract
IMPORTANCE Polymicrobial infections are common. In chronic infections, the different pathogens may repeatedly interact, which could spur evolutionary dynamics with pathogens adapting to one another. Here, we explore the potential of Staphylococcus aureus to adapt to its competitor Pseudomonas aeruginosa. These two pathogens frequently co-occur, and P. aeruginosa is seen as the dominant species being able to displace S. aureus. We studied three different S. aureus strains and found that all became quickly resistant to inhibitory compounds secreted by P. aeruginosa. Our experimental evolution revealed strains-specific adaptations with three main factors contributing to resistance evolution: (i) overproduction of staphyloxanthin, a molecule protecting from oxidative stress; (ii) the formation of small colony variants also protecting from oxidative stress; and (iii) alterations of membrane transporters possibly reducing toxin uptake. Our results show that species interactions can change over time potentially favoring species co-existence, which in turn could affect disease progression and treatment options.
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Affiliation(s)
- Selina Niggli
- Department of Quantitative Biomedicine, University of Zurich, Winterthurerstrasse, Zurich, Switzerland
| | - Lukas Schwyter
- Department of Quantitative Biomedicine, University of Zurich, Winterthurerstrasse, Zurich, Switzerland
| | - Lucy Poveda
- Functional Genomics Center Zurich, ETH Zurich and University of Zurich, Winterthurerstrasse, Zurich, Switzerland
- Swiss Institute of Bioinformatics (SIB) Quartier Sorge-Batiment Amphipole, Lausanne, Switzerland
| | - Jonas Grossmann
- Functional Genomics Center Zurich, ETH Zurich and University of Zurich, Winterthurerstrasse, Zurich, Switzerland
- Swiss Institute of Bioinformatics (SIB) Quartier Sorge-Batiment Amphipole, Lausanne, Switzerland
| | - Rolf Kümmerli
- Department of Quantitative Biomedicine, University of Zurich, Winterthurerstrasse, Zurich, Switzerland
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9
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Kawashima K, Nagakubo T, Nomura N, Toyofuku M. Iron Delivery through Membrane Vesicles in Corynebacterium glutamicum. Microbiol Spectr 2023; 11:e0122223. [PMID: 37154718 PMCID: PMC10269601 DOI: 10.1128/spectrum.01222-23] [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: 03/22/2023] [Accepted: 04/14/2023] [Indexed: 05/10/2023] Open
Abstract
Bacterial cells form and release membrane vesicles (MVs) originating from cellular membranes. In recent years, many biological functions of bacterial MVs have been identified. Here, we show that MVs derived from Corynebacterium glutamicum, a model organism for mycolic acid-containing bacteria, can mediate iron acquisition and other phylogenetically related bacteria. Lipid/protein analysis and iron quantification assay indicate that C. glutamicum MVs formed by outer mycomembrane blebbing can load ferric iron (Fe3+) as its cargo. Iron-loaded C. glutamicum MVs promoted the growth of producer bacteria in iron-limited liquid media. MVs were received by C. glutamicum cells, suggesting a direct transfer of iron to the recipient cells. Cross-feeding of C. glutamicum MVs with phylogenetically close (Mycobacterium smegmatis and Rhodococcus erythropolis) or distant (Bacillus subtilis) bacteria indicated that C. glutamicum MVs could be received by the different species tested, while iron uptake is limited to M. smegmatis and R. erythropolis. In addition, our results indicate that iron loading on MVs in C. glutamicum does not depend on membrane-associated proteins or siderophores, which is different from what has been shown in other mycobacterial species. Our findings illustrate the biological importance of MV-associated extracellular iron for C. glutamicum growth and suggest its ecological impact on selected members of microbial communities. IMPORTANCE Iron is an essential element of life. Many bacteria have developed iron acquisition systems, such as siderophores, for external iron uptake. Corynebacterium glutamicum, a soil bacterium known for its potential for industrial applications, was shown to lack the ability to produce extracellular, low-molecular-weight iron carriers, and it remains elusive how this bacterium acquires iron. Here, we demonstrated that MVs released from C. glutamicum cells could act as extracellular iron carriers that mediate iron uptake. Although MV-associated proteins or siderophores have been shown to play critical roles in MV-mediated iron uptake by other mycobacterial species, the iron delivery through C. glutamicum MVs is not dependent on these factors. Moreover, our results suggest that there is an unidentified mechanism that determines the species specificity of MV-mediated iron acquisition. Our results further demonstrated the important role of MV-associated iron.
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Affiliation(s)
- Kayuki Kawashima
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Toshiki Nagakubo
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
- Microbiology Research Center for Sustainability (MiCS), University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Nobuhiko Nomura
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
- Microbiology Research Center for Sustainability (MiCS), University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Masanori Toyofuku
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
- Microbiology Research Center for Sustainability (MiCS), University of Tsukuba, Tsukuba, Ibaraki, Japan
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10
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Giallonardi G, Letizia M, Mellini M, Frangipani E, Halliday N, Heeb S, Cámara M, Visca P, Imperi F, Leoni L, Williams P, Rampioni G. Alkyl-quinolone-dependent quorum sensing controls prophage-mediated autolysis in Pseudomonas aeruginosa colony biofilms. Front Cell Infect Microbiol 2023; 13:1183681. [PMID: 37305419 PMCID: PMC10250642 DOI: 10.3389/fcimb.2023.1183681] [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: 03/10/2023] [Accepted: 05/02/2023] [Indexed: 06/13/2023] Open
Abstract
Pseudomonas aeruginosa is a model quorum sensing (QS) pathogen with three interconnected QS circuits that control the production of virulence factors and antibiotic tolerant biofilms. The pqs QS system of P. aeruginosa is responsible for the biosynthesis of diverse 2-alkyl-4-quinolones (AQs), of which 2-heptyl-4-hydroxyquinoline (HHQ) and 2-heptyl-3-hydroxy-4(1H)-quinolone (PQS) function as QS signal molecules. Transcriptomic analyses revealed that HHQ and PQS influenced the expression of multiple genes via PqsR-dependent and -independent pathways whereas 2-heptyl-4-hydroxyquinoline N-oxide (HQNO) had no effect on P. aeruginosa transcriptome. HQNO is a cytochrome bc 1 inhibitor that causes P. aeruginosa programmed cell death and autolysis. However, P. aeruginosa pqsL mutants unable to synthesize HQNO undergo autolysis when grown as colony biofilms. The mechanism by which such autolysis occurs is not understood. Through the generation and phenotypic characterization of multiple P. aeruginosa PAO1 mutants producing altered levels of AQs in different combinations, we demonstrate that mutation of pqsL results in the accumulation of HHQ which in turn leads to Pf4 prophage activation and consequently autolysis. Notably, the effect of HHQ on Pf4 activation is not mediated via its cognate receptor PqsR. These data indicate that the synthesis of HQNO in PAO1 limits HHQ-induced autolysis mediated by Pf4 in colony biofilms. A similar phenomenon is shown to occur in P. aeruginosa cystic fibrosis (CF) isolates, in which the autolytic phenotype can be abrogated by ectopic expression of pqsL.
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Affiliation(s)
| | | | - Marta Mellini
- Department of Science, University Roma Tre, Rome, Italy
| | | | - Nigel Halliday
- National Biofilms Innovation Centre, Biodiscovery Institute and School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Stephan Heeb
- National Biofilms Innovation Centre, Biodiscovery Institute and School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Miguel Cámara
- National Biofilms Innovation Centre, Biodiscovery Institute and School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Paolo Visca
- Department of Science, University Roma Tre, Rome, Italy
- IRCCS Fondazione Santa Lucia, Rome, Italy
- NBFC, National Biodiversity Future Center, Palermo, Italy
| | - Francesco Imperi
- Department of Science, University Roma Tre, Rome, Italy
- IRCCS Fondazione Santa Lucia, Rome, Italy
- NBFC, National Biodiversity Future Center, Palermo, Italy
| | - Livia Leoni
- Department of Science, University Roma Tre, Rome, Italy
| | - Paul Williams
- National Biofilms Innovation Centre, Biodiscovery Institute and School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Giordano Rampioni
- Department of Science, University Roma Tre, Rome, Italy
- IRCCS Fondazione Santa Lucia, Rome, Italy
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11
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Sánchez-Jiménez A, Marcos-Torres FJ, Llamas MA. Mechanisms of iron homeostasis in Pseudomonas aeruginosa and emerging therapeutics directed to disrupt this vital process. Microb Biotechnol 2023. [PMID: 36857468 DOI: 10.1111/1751-7915.14241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 02/13/2023] [Indexed: 03/03/2023] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen able to infect any human tissue. One of the reasons for its high adaptability and colonization of host tissues is its capacity of maintaining iron homeostasis through a wide array of iron acquisition and removal mechanisms. Due to their ability to cause life-threatening acute and chronic infections, especially among cystic fibrosis and immunocompromised patients, and their propensity to acquire resistance to many antibiotics, the World Health Organization (WHO) has encouraged the scientific community to find new strategies to eradicate this pathogen. Several recent strategies to battle P. aeruginosa focus on targeting iron homeostasis mechanisms, turning its greatest advantage into an exploitable weak point. In this review, we discuss the different mechanisms used by P. aeruginosa to maintain iron homeostasis and the strategies being developed to fight this pathogen by blocking these mechanisms. Among others, the use of iron chelators and mimics, as well as disruption of siderophore production and uptake, have shown promising results in reducing viability and/or virulence of this pathogen. The so-called 'Trojan-horse' strategy taking advantage of the siderophore uptake systems is emerging as an efficient method to improve delivery of antibiotics into the bacterial cells. Moreover, siderophore transporters are considered promising targets for the developing of P. aeruginosa vaccines.
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Affiliation(s)
- Ana Sánchez-Jiménez
- Department of Biotechnology and Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - Francisco J Marcos-Torres
- Department of Biotechnology and Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - María A Llamas
- Department of Biotechnology and Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, Granada, Spain
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12
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Proteomic Profiling Reveals Distinct Bacterial Extracellular Vesicle Subpopulations with Possibly Unique Functionality. Appl Environ Microbiol 2023; 89:e0168622. [PMID: 36533919 PMCID: PMC9888257 DOI: 10.1128/aem.01686-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Bacterial outer membrane vesicles (OMVs) are 20- to 200-nm secreted packages of lipids, small molecules, and proteins that contribute to diverse bacterial processes. In plant systems, OMVs from pathogenic and beneficial strains elicit plant immune responses that inhibit seedling growth and protect against future pathogen challenge. Previous studies of OMV-plant interactions suggest functionally important differences in the protein composition of Pseudomonas syringae and Pseudomonas fluorescens OMVs, and that their composition and activity differ as a result of medium culture conditions. Here, we show that plant apoplast-mimicking minimal medium conditions impact OMV protein content dramatically in P. syringae but not in P. fluorescens relative to complete medium conditions. Comparative, 2-way analysis of the four conditions reveals subsets of proteins that may contribute to OMV-mediated bacterial virulence and plant immune activation as well as those involved in bacterial stress tolerance or adaptation to a beneficial relationship with plants. Additional localization enrichment analysis of these subsets suggests the presence of outer-inner membrane vesicles (OIMVs). Collectively, these results reveal distinct differences in bacterial extracellular vesicle cargo and biogenesis routes from pathogenic and beneficial plant bacteria in different medium conditions and point to distinct populations of vesicles with diverse functional roles. IMPORTANCE Recent publications have shown that bacterial vesicles play important roles in interkingdom communication between bacteria and plants. Indeed, our recently published data reveal that bacterial vesicles from pathogenic and beneficial strains elicit immune responses in plants that protect against future pathogen challenge. However, the molecules underlying these striking phenomena remain unknown. Our recent work indicated that proteins packaged in vesicles are critically important for vesicle-mediated seedling growth inhibition, often considered an indirect measure of plant immune activation. In this study, we characterize the protein cargo of vesicles from Pseudomonas syringae pathovar tomato DC3000 and Pseudomonas fluorescens from two different medium conditions and show that distinct subpopulations of vesicles contribute to bacterial virulence and stress tolerance. Furthermore, we reveal differences in how beneficial and pathogenic bacterial species respond to harsh environmental conditions through vesicle packaging. Importantly, we find that protein cargo implicates outer-inner membrane vesicles in bacterial stress responses, while outer membrane vesicles are packaged for virulence.
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13
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Pseudomonas aeruginosa H3-T6SS Combats H 2O 2 Stress by Diminishing the Amount of Intracellular Unincorporated Iron in a Dps-Dependent Manner and Inhibiting the Synthesis of PQS. Int J Mol Sci 2023; 24:ijms24021614. [PMID: 36675127 PMCID: PMC9866239 DOI: 10.3390/ijms24021614] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 12/28/2022] [Accepted: 01/10/2023] [Indexed: 01/17/2023] Open
Abstract
The type VI secretion system (T6SS), a protein translocation nanomachine, is widely distributed in Gram-negative bacteria and delivers effectors directly into target cells or the extracellular environment to help the bacteria gain a competitive fitness advantage and promote bacterial survival in harmful environments. In this study, we demonstrated that the synthesis of the Pseudomonas quinolone signal (PQS) in Pseudomonas aeruginosa PAO1 was inhibited by the H3-T6SS gene cluster under iron-rich conditions, and that this inhibition was relieved under iron starvation conditions. Conversely, PQS differentially regulated the expression of the H3-T6SS structural genes and the effector protein gene tseF. The expression of tseF was inhibited by PQS, while the expressions of the H3-T6SS structural genes were positively regulated by PQS. Further studies showed that the H3-T6SS was involved in the resistance of P. aeruginosa to oxidative stress caused by hydrogen peroxide (H2O2). Interestingly, H3-T6SS expression was neither induced by H2O2 stress nor regulated by OxyR (a global anti-oxidative transcriptional regulator) but was positively regulated by RpoS (a major transcription regulator of the stress response). In addition, we found that the clpV3 (a structural gene of H3-T6SS) mutation resulted in upregulation of two proteins related to PQS synthesis and many proteins related to oxidative stress resistance, while the expression of some iron storage proteins, especially Dps, were significantly downregulated. Furthermore, the clpV3 mutation led to an increase in the intracellular free Fe2+ content of P. aeruginosa. Further studies showed that both the PQS deficient mutation and overexpression of dps effectively restored the H2O2 sensitive phenotype of the H3-T6SS mutant. Finally, we proposed the following model of H3-T6SS-mediated resistance to H2O2 stress in P. aeruginosa. H3-T6SS not only reduces the intracellular free Fe2+ level by upregulating the expression of ferritin Dps, but also inhibits the synthesis of PQS to mediate the resistance of P. aeruginosa to H2O2 stress. This study highlights the important role of H3-T6SS in the ability of P. aeruginosa to combat H2O2 stress and provides a perspective for understanding the stress response mechanism of bacteria.
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14
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Temporal Hierarchy and Context-Dependence of Quorum Sensing Signal in Pseudomonas aeruginosa. LIFE (BASEL, SWITZERLAND) 2022; 12:life12121953. [PMID: 36556318 PMCID: PMC9781131 DOI: 10.3390/life12121953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 11/15/2022] [Accepted: 11/18/2022] [Indexed: 11/24/2022]
Abstract
The Gram-negative bacterium Pseudomonas aeruginosa can cause infections in a broad range of hosts including plants, invertebrates and mammals and is an important source of nosocomial infections in humans. We were interested in how differences in the bacteria's nutritional environment impact bacterial communication and virulence factor production. We grew P. aeruginosa in 96 different conditions in BIOLOG Gen III plates and assayed quorum sensing (QS) signaling over the course of growth. We also quantified pyocyanin and biofilm production and the impact of sub-inhibitory exposure to tobramycin. We found that while 3-oxo-C12 homoserine lactone remained the dominant QS signal to be produced, timing of PQS production differed between media types. Further, whether cells grew predominantly as biofilms or planktonic cells was highly context dependent. Our data suggest that understanding the impact of the nutritional environment on the bacterium can lead to valuable insights into the link between bacterial physiology and pathology.
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15
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Ogbechi J, Huang YS, Clanchy FIL, Pantazi E, Topping LM, Darlington LG, Williams RO, Stone TW. Modulation of immune cell function, IDO expression and kynurenine production by the quorum sensor 2-heptyl-3-hydroxy-4-quinolone (PQS). Front Immunol 2022; 13:1001956. [PMID: 36389710 PMCID: PMC9650388 DOI: 10.3389/fimmu.2022.1001956] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2022] [Accepted: 10/05/2022] [Indexed: 12/29/2023] Open
Abstract
Many invasive micro-organisms produce 'quorum sensor' molecules which regulate colony expansion and may modulate host immune responses. We have examined the ability of Pseudomonas Quorum Sensor (PQS) to influence cytokine expression under conditions of inflammatory stress. The administration of PQS in vivo to mice with collagen-induced arthritis (CIA) increased the severity of disease. Blood and inflamed paws from treated mice had fewer regulatory T cells (Tregs) but normal numbers of Th17 cells. However, PQS (1μM) treatment of antigen-stimulated lymph node cells from collagen-immunised mice in vitro inhibited the differentiation of CD4+IFNγ+ cells, with less effect on CD4+IL-17+ cells and no change in CD4+FoxP3+Tregs. PQS also inhibited T cell activation by anti-CD3/anti-CD28 antibodies. PQS reduced murine macrophage polarisation and inhibited expression of IL1B and IL6 genes in murine macrophages and human THP-1 cells. In human monocyte-derived macrophages, IDO1 gene, protein and enzyme activity were all inhibited by exposure to PQS. TNF gene expression was inhibited in THP-1 cells but not murine macrophages, while LPS-induced TNF protein release was increased by high PQS concentrations. PQS is known to have iron scavenging activity and its suppression of cytokine release was abrogated by iron supplementation. Unexpectedly, PQS decreased the expression of indoleamine-2, 3-dioxygenase genes (IDO1 and IDO2), IDO1 protein expression and enzyme activity in mouse and human macrophages. This is consistent with evidence that IDO1 inhibition or deletion exacerbates arthritis, while kynurenine reduces its severity. It is suggested that the inhibition of IDO1 and cytokine expression may contribute to the quorum sensor and invasive actions of PQS.
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Affiliation(s)
- Joy Ogbechi
- The Kennedy Institute of Rheumatology, Nuffield Department of Orthopaedics, Rheumatology and Musculo-skeletal Sciences (NDORMS), University of Oxford, Oxford, United Kingdom
| | - Yi-Shu Huang
- The Kennedy Institute of Rheumatology, Nuffield Department of Orthopaedics, Rheumatology and Musculo-skeletal Sciences (NDORMS), University of Oxford, Oxford, United Kingdom
| | - Felix I. L. Clanchy
- The Kennedy Institute of Rheumatology, Nuffield Department of Orthopaedics, Rheumatology and Musculo-skeletal Sciences (NDORMS), University of Oxford, Oxford, United Kingdom
| | - Eirini Pantazi
- The Kennedy Institute of Rheumatology, Nuffield Department of Orthopaedics, Rheumatology and Musculo-skeletal Sciences (NDORMS), University of Oxford, Oxford, United Kingdom
| | - Louise M. Topping
- The Kennedy Institute of Rheumatology, Nuffield Department of Orthopaedics, Rheumatology and Musculo-skeletal Sciences (NDORMS), University of Oxford, Oxford, United Kingdom
| | | | - Richard O. Williams
- The Kennedy Institute of Rheumatology, Nuffield Department of Orthopaedics, Rheumatology and Musculo-skeletal Sciences (NDORMS), University of Oxford, Oxford, United Kingdom
| | - Trevor W. Stone
- The Kennedy Institute of Rheumatology, Nuffield Department of Orthopaedics, Rheumatology and Musculo-skeletal Sciences (NDORMS), University of Oxford, Oxford, United Kingdom
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16
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Abstract
Pf4 is a filamentous bacteriophage integrated as a prophage into the genome of Pseudomonas aeruginosa PAO1. Pf4 virions can be produced without killing P. aeruginosa. However, cell lysis can occur during superinfection when Pf virions successfully infect a host lysogenized by a Pf superinfective variant. We have previously shown that infection of P. aeruginosa PAO1 with a superinfective Pf4 variant abolished twitching motility and altered biofilm architecture. More precisely, most of the cells embedded into the biofilm were showing a filamentous morphology, suggesting the activation of the cell envelope stress response involving both AlgU and SigX extracytoplasmic function sigma factors. Here, we show that Pf4 variant infection results in a drastic dysregulation of 3,360 genes representing about 58% of P. aeruginosa genome; of these, 70% of the virulence factors encoding genes show a dysregulation. Accordingly, Pf4 variant infection (termed Pf4*) causes in vivo reduction of P. aeruginosa virulence and decreased production of N-acyl-homoserine lactones and 2-alkyl-4-quinolones quorum-sensing molecules and related virulence factors, such as pyocyanin, elastase, and pyoverdine. In addition, the expression of genes involved in metabolism, including energy generation and iron homeostasis, was affected, suggesting further relationships between virulence and central metabolism. Altogether, these data show that Pf4 phage variant infection results in complex network dysregulation, leading to reducing acute virulence in P. aeruginosa. This study contributes to the comprehension of the bacterial response to filamentous phage infection. IMPORTANCE Filamentous bacteriophages can become superinfective and infect P. aeruginosa, even though they are inserted in the genome as lysogens. Despite this productive infection, growth of the host is only mildly affected, allowing the study of the interaction between the phage and the host, which is not possible in the case of lytic phages killing rapidly their host. Here, we demonstrate by transcriptome and phenotypic analysis that the infection by a superinfective filamentous phage variant causes a massive disruption in gene expression, including those coding for virulence factors and metabolic pathways.
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17
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Zgurskaya HI, Adamiak JW, Leus IV. Making sense of drug-efflux transporters in the physiological environment. Curr Opin Microbiol 2022; 69:102179. [PMID: 35882103 PMCID: PMC9942525 DOI: 10.1016/j.mib.2022.102179] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 06/23/2022] [Accepted: 06/24/2022] [Indexed: 02/06/2023]
Abstract
Bacterial drug-efflux transporters act synergistically with diffusion barriers of cellular membranes and other resistance mechanisms to protect cells from antibiotics and toxic metabolites. Their critical roles in clinical antibiotic and multidrug resistance are well established. In addition, a large body of evidence has been accumulated in support of their important contributions to bacterial growth and proliferation during infections. However, how these diverse functions of drug transporters are integrated at the level of bacterial cell physiology remains unclear. This opinion briefly summarizes the current understanding of substrate specificities and physiological roles of drug-efflux pumps from Resistance-Nodulation-Division (RND) superfamily of proteins in two ESKAPE pathogens Pseudomonas aeruginosa and Acinetobacter baumannii. Based on the analysis of phenotypic and transcriptomic studies in vitro and in vivo, we propose that RND pumps of Gram-negative bacteria fall into three categories: constitutively expressed, regulated, and silent. These three categories of efflux pumps participate in different physiological programs, which are not involved in the central metabolism and bacterial growth.
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Affiliation(s)
- Helen I Zgurskaya
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK 73072, USA.
| | - Justyna W Adamiak
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK 73072, USA
| | - Inga V Leus
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK 73072, USA
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18
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Hills OJ, Yong CW, Scott AJ, Devine DA, Smith J, Chappell HF. Atomic-scale interactions between quorum sensing autoinducer molecules and the mucoid P. aeruginosa exopolysaccharide matrix. Sci Rep 2022; 12:7724. [PMID: 35545629 PMCID: PMC9095684 DOI: 10.1038/s41598-022-11499-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 04/18/2022] [Indexed: 12/22/2022] Open
Abstract
Mucoid Pseudomonas aeruginosa is a prevalent cystic fibrosis (CF) lung coloniser whose chronicity is associated with the formation of cation cross-linked exopolysaccharide (EPS) matrices, which form a biofilm that acts as a diffusion barrier, sequestering cationic and neutral antimicrobials, and making it extremely resistant to pharmacological challenge. Biofilm chronicity and virulence of the colony is regulated by quorum sensing autoinducers (QSAIs), small signalling metabolites that pass between bacteria, through the biofilm matrix, regulating genetic responses on a population-wide scale. The nature of how these molecules interact with the EPS is poorly understood, despite the fact that they must pass through EPS matrix to reach neighbouring bacteria. Interactions at the atomic-scale between two QSAI molecules, C4-HSL and PQS—both utilised by mucoid P. aeruginosa in the CF lung—and the EPS, have been studied for the first time using a combined molecular dynamics (MD) and density functional theory (DFT) approach. A large-scale, calcium cross-linked, multi-chain EPS molecular model was developed and MD used to sample modes of interaction between QSAI molecules and the EPS that occur at physiological equilibrium. The thermodynamic stability of the QSAI-EPS adducts were calculated using DFT. These simulations provide a thermodynamic rationale for the apparent free movement of C4-HSL, highlight key molecular functionality responsible for EPS binding and, based on its significantly reduced mobility, suggest PQS as a viable target for quorum quenching.
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Affiliation(s)
- Oliver J Hills
- School of Food Science & Nutrition, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK.
| | - Chin W Yong
- Daresbury Laboratory, Scientific Computing Department, Science and Technology Facilities Council, Keckwick Lane, Daresbury, Warrington, WA4 4AD, UK.,Division of Pharmacy and Optometry, School of Health Sciences, University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Andrew J Scott
- School of Chemical & Process Engineering, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK
| | - Deirdre A Devine
- School of Dentistry, University of Leeds, Clarendon Way, Leeds, LS2 9LU, UK
| | - James Smith
- School of Food Science & Nutrition, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK
| | - Helen F Chappell
- School of Food Science & Nutrition, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK.
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19
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Coyne KJ, Wang Y, Johnson G. Algicidal Bacteria: A Review of Current Knowledge and Applications to Control Harmful Algal Blooms. Front Microbiol 2022; 13:871177. [PMID: 35464927 PMCID: PMC9022068 DOI: 10.3389/fmicb.2022.871177] [Citation(s) in RCA: 37] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 03/01/2022] [Indexed: 12/19/2022] Open
Abstract
Interactions between bacteria and phytoplankton in aqueous ecosystems are both complex and dynamic, with associations that range from mutualism to parasitism. This review focuses on algicidal interactions, in which bacteria are capable of controlling algal growth through physical association or the production of algicidal compounds. While there is some evidence for bacterial control of algal growth in the field, our understanding of these interactions is largely based on laboratory culture experiments. Here, the range of these algicidal interactions is discussed, including specificity of bacterial control, mechanisms for activity, and insights into the chemical and biochemical analysis of these interactions. The development of algicidal bacteria or compounds derived from bacteria for control of harmful algal blooms is reviewed with a focus on environmentally friendly or sustainable methods of application. Potential avenues for future research and further development and application of bacterial algicides for the control of algal blooms are presented.
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Affiliation(s)
- Kathryn J. Coyne
- College of Earth, Ocean, and Environment, University of Delaware, Lewes, DE, United States
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20
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Perry EK, Meirelles LA, Newman DK. From the soil to the clinic: the impact of microbial secondary metabolites on antibiotic tolerance and resistance. Nat Rev Microbiol 2022; 20:129-142. [PMID: 34531577 PMCID: PMC8857043 DOI: 10.1038/s41579-021-00620-w] [Citation(s) in RCA: 37] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/02/2021] [Indexed: 02/08/2023]
Abstract
Secondary metabolites profoundly affect microbial physiology, metabolism and stress responses. Increasing evidence suggests that these molecules can modulate microbial susceptibility to commonly used antibiotics; however, secondary metabolites are typically excluded from standard antimicrobial susceptibility assays. This may in part account for why infections by diverse opportunistic bacteria that produce secondary metabolites often exhibit discrepancies between clinical antimicrobial susceptibility testing results and clinical treatment outcomes. In this Review, we explore which types of secondary metabolite alter antimicrobial susceptibility, as well as how and why this phenomenon occurs. We discuss examples of molecules that opportunistic and enteric pathogens either generate themselves or are exposed to from their neighbours, and the nuanced impacts these molecules can have on tolerance and resistance to certain antibiotics.
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Affiliation(s)
- Elena K Perry
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Lucas A Meirelles
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Dianne K Newman
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA.
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA.
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21
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Dual Effect: High NADH Levels Contribute to Efflux-Mediated Antibiotic Resistance but Drive Lethality Mediated by Reactive Oxygen Species. mBio 2022; 13:e0243421. [PMID: 35038918 PMCID: PMC8764520 DOI: 10.1128/mbio.02434-21] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
In light of the antibiotic crisis, emerging strategies to sensitize bacteria to available antibiotics should be explored. Several studies on the mechanisms of killing suggest that bactericidal antibiotic activity is enforced through the generation of reactive oxygen species (ROS-lethality hypothesis). Here, we artificially manipulated the redox homeostasis of the model opportunistic pathogen Pseudomonas aeruginosa using specific enzymes that catalyze either the formation or oxidation of NADH. Increased NADH levels led to the activation of antibiotic efflux pumps and high levels of antibiotic resistance. However, higher NADH levels also resulted in increased intracellular ROS and amplified antibiotic killing. Our results demonstrate that growth inhibition and killing activity are mediated via different mechanisms. Furthermore, the profound changes in bioenergetics produced low-virulence phenotypes characterized by reduced interbacterial signaling controlled pathogenicity traits. Our results pave the way for a more effective infection resolution and add an antivirulence strategy to maximize chances to combat devastating P. aeruginosa infections while reducing the overall use of antibiotics. IMPORTANCE The emergence of antibiotic resistance has become one of the major threats to public health. A better understanding of antimicrobial killing mechanisms promises to uncover new ways to resensitize bacteria to commonly used antibiotics. In this context, there is increasing evidence that the metabolic status of the cell plays a fundamental role in reactive oxygen species (ROS)-mediated cell death. In this work, we artificially manipulated the redox balance in Pseudomonas aeruginosa by the expression of two orthologous enzymes. We found that the increase of intracellular NADH concentrations leads to higher antibiotic resistance but also generates a burst in the production of ROS that amplified antimicrobial killing. Our work suggests that the combination of bactericidal antibiotics with agents that disturb the cellular redox homeostasis could significantly enhance antibiotic killing via sensitization of pathogens to currently available antibiotics.
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22
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Outer Membrane Vesicles (OMVs) of Pseudomonas aeruginosa Provide Passive Resistance but Not Sensitization to LPS-Specific Phages. Viruses 2022; 14:v14010121. [PMID: 35062325 PMCID: PMC8778925 DOI: 10.3390/v14010121] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 01/05/2022] [Accepted: 01/06/2022] [Indexed: 02/06/2023] Open
Abstract
Outer membrane vesicles (OMVs) released from gram-negative bacteria are key elements in bacterial physiology, pathogenesis, and defence. In this study, we investigated the role of Pseudomonas aeruginosa OMVs in the anti-phage defence as well as in the potential sensitization to LPS-specific phages. Using transmission electron microscopy, virion infectivity, and neutralization assays, we have shown that both phages efficiently absorb on free vesicles and are unable to infect P. aeruginosa host. Nevertheless, the accompanying decrease in PFU titre (neutralization) was only observed for myovirus KT28 but not podovirus LUZ7. Next, we verified whether OMVs derived from wild-type PAO1 strain can sensitize the LPS-deficient mutant (Δwbpl PAO1) resistant to tested phages. The flow cytometry experiments proved a quite effective and comparable association of OMVs to Δwbpl PAO1 and wild-type PAO1; however, the growth kinetic curves and one-step growth assay revealed no sensitization event of the OMV-associated phage-resistant P. aeruginosa deletant to LPS-specific phages. Our findings for the first time identify naturally formed OMVs as important players in passive resistance (protection) of P. aeruginosa population to phages, but we disproved the hypothesis of transferring phage receptors to make resistant strains susceptible to LPS-dependent phages.
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23
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Iron Homeostasis in Pseudomonas aeruginosa: Targeting Iron Acquisition and Storage as an Antimicrobial Strategy. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1386:29-68. [DOI: 10.1007/978-3-031-08491-1_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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24
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Toyofuku M, Kikuchi Y, Taoka A. A Single Shot of Vesicles. Microbes Environ 2022; 37. [PMID: 36504177 PMCID: PMC10037094 DOI: 10.1264/jsme2.me22083] [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] [Indexed: 12/13/2022] Open
Abstract
Bacteria communicate through signaling molecules that coordinate group behavior. Hydrophobic signals that do not diffuse in aqueous environments are used as signaling molecules by several bacteria. However, limited information is currently available on the mechanisms by which these molecules are transported between cells. Membrane vesicles (MVs) with diverse functions play important roles in the release and delivery of hydrophobic signaling molecules, leading to differences in the dynamics of signal transportation from those of free diffusion. Studies on Paracoccus denitrificans, which produces a hydrophobic long-chain N-acyl homoserine lactone (AHL), showed that signals were loaded into MVs at a concentration with the potential to trigger the quorum sensing (QS) response with a "single shot" to the cell. Furthermore, stimulating the formation of MVs increased the release of signals from the cell; therefore, a basic understanding of MV formation is important. Novel findings revealed the formation of MVs through different routes, resulting in the production of different types of MVs. Methods such as high-speed atomic force microscopy (AFM) phase imaging allow the physical properties of MVs to be analyzed at a nanometer resolution, revealing their heterogeneity. In this special minireview, we introduce the role of MVs in bacterial communication and highlight recent findings on MV formation and their physical heterogeneity by referring to our research. We hope that this minireview will provide basic information for understanding the functionality of MVs in ecological systems.
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Affiliation(s)
- Masanori Toyofuku
- Faculty of Life and Environmental Sciences, University of Tsukuba
- Microbiology Research Center for Sustainability (MiCS), University of Tsukuba
| | - Yousuke Kikuchi
- WPI Nano Life Science Institute (WPI-NanoLSI), Kanazawa University
| | - Azuma Taoka
- WPI Nano Life Science Institute (WPI-NanoLSI), Kanazawa University
- Institute of Science and Engineering, Kanazawa University
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25
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Yang X, Liu H, Zhang Y, Shen X. Roles of Type VI Secretion System in Transport of Metal Ions. Front Microbiol 2021; 12:756136. [PMID: 34803980 PMCID: PMC8602904 DOI: 10.3389/fmicb.2021.756136] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 10/12/2021] [Indexed: 11/18/2022] Open
Abstract
The type VI secretion system (T6SS) is a transmembrane protein nanomachine employed by many gram-negative bacteria to directly translocate effectors into adjacent cells or the extracellular milieu, showing multiple functions in both interbacterial competition and bacteria-host interactions. Metal ion transport is a newly discovered T6SS function. This review summarizes the identified T6SS functions and highlights the features of metal ion transport mediated by T6SS and discusses its regulation.
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Affiliation(s)
- Xiaobing Yang
- College of Applied Engineering, Henan University of Science and Technology (HAUST), Sanmenxia, China.,Medical College, Sanmenxia Vocational Technical School, Sanmenxia, China
| | - Hai Liu
- Qingyang Longfeng Sponge City Construction Management & Operation Co., Ltd, Qingyang, China
| | - Yanxiong Zhang
- Qingyang Longfeng Sponge City Construction Management & Operation Co., Ltd, Qingyang, China
| | - Xihui Shen
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Xianyang, China
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26
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Coquant G, Aguanno D, Pham S, Grellier N, Thenet S, Carrière V, Grill JP, Seksik P. Gossip in the gut: Quorum sensing, a new player in the host-microbiota interactions. World J Gastroenterol 2021; 27:7247-7270. [PMID: 34876787 PMCID: PMC8611211 DOI: 10.3748/wjg.v27.i42.7247] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 08/17/2021] [Accepted: 10/27/2021] [Indexed: 02/06/2023] Open
Abstract
Bacteria are known to communicate with each other and regulate their activities in social networks by secreting and sensing signaling molecules called autoinducers, a process known as quorum sensing (QS). This is a growing area of research in which we are expanding our understanding of how bacteria collectively modify their behavior but are also involved in the crosstalk between the host and gut microbiome. This is particularly relevant in the case of pathologies associated with dysbiosis or disorders of the intestinal ecosystem. This review will examine the different QS systems and the evidence for their presence in the intestinal ecosystem. We will also provide clues on the role of QS molecules that may exert, directly or indirectly through their bacterial gossip, an influence on intestinal epithelial barrier function, intestinal inflammation, and intestinal carcinogenesis. This review aims to provide evidence on the role of QS molecules in gut physiology and the potential shared by this new player. Better understanding the impact of intestinal bacterial social networks and ultimately developing new therapeutic strategies to control intestinal disorders remains a challenge that needs to be addressed in the future.
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Affiliation(s)
- Garance Coquant
- Centre de Recherche Saint-Antoine, INSERM, Sorbonne Université, Paris 75012, France
| | - Doriane Aguanno
- Centre de Recherche Saint-Antoine, INSERM, Sorbonne Université, Paris 75012, France
- EPHE, PSL University, Paris 75014, France
| | - Sandrine Pham
- Centre de Recherche Saint-Antoine, INSERM, Sorbonne Université, Paris 75012, France
- EPHE, PSL University, Paris 75014, France
| | - Nathan Grellier
- Centre de Recherche Saint-Antoine, INSERM, Sorbonne Université, Paris 75012, France
| | - Sophie Thenet
- Centre de Recherche Saint-Antoine, INSERM, Sorbonne Université, Paris 75012, France
- EPHE, PSL University, Paris 75014, France
| | - Véronique Carrière
- Centre de Recherche Saint-Antoine, INSERM, Sorbonne Université, Paris 75012, France
| | - Jean-Pierre Grill
- Centre de Recherche Saint-Antoine, INSERM, Sorbonne Université, Paris 75012, France
| | - Philippe Seksik
- Centre de Recherche Saint-Antoine, INSERM, Sorbonne Université, Paris 75012, France
- Department of Gastroenterology and Nutrition, Saint-Antoine Hospital, APHP, Paris 75012, France
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27
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McMillan HM, Kuehn MJ. The extracellular vesicle generation paradox: a bacterial point of view. EMBO J 2021; 40:e108174. [PMID: 34636061 PMCID: PMC8561641 DOI: 10.15252/embj.2021108174] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 06/29/2021] [Accepted: 07/28/2021] [Indexed: 12/23/2022] Open
Abstract
All bacteria produce secreted vesicles that carry out a variety of important biological functions. These extracellular vesicles can improve adaptation and survival by relieving bacterial stress and eliminating toxic compounds, as well as by facilitating membrane remodeling and ameliorating inhospitable environments. However, vesicle production comes with a price. It is energetically costly and, in the case of colonizing pathogens, it elicits host immune responses, which reduce bacterial viability. This raises an interesting paradox regarding why bacteria produce vesicles and begs the question as to whether the benefits of producing vesicles outweigh their costs. In this review, we discuss the various advantages and disadvantages associated with Gram-negative and Gram-positive bacterial vesicle production and offer perspective on the ultimate score. We also highlight questions needed to advance the field in determining the role for vesicles in bacterial survival, interkingdom communication, and virulence.
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Affiliation(s)
- Hannah M McMillan
- Department of Molecular Genetics and MicrobiologyDuke UniversityDurhamNCUSA
| | - Meta J Kuehn
- Department of BiochemistryDuke UniversityDurhamNCUSA
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28
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Bach E, Passaglia LMP, Jiao J, Gross H. Burkholderia in the genomic era: from taxonomy to the discovery of new antimicrobial secondary metabolites. Crit Rev Microbiol 2021; 48:121-160. [PMID: 34346791 DOI: 10.1080/1040841x.2021.1946009] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Species of Burkholderia are highly versatile being found not only abundantly in soil, but also as plants and animals' commensals or pathogens. Their complex multireplicon genomes harbour an impressive number of polyketide synthase (PKS) and nonribosomal peptide-synthetase (NRPS) genes coding for the production of antimicrobial secondary metabolites (SMs), which have been successfully deciphered by genome-guided tools. Moreover, genome metrics supported the split of this genus into Burkholderia sensu stricto (s.s.) and five new other genera. Here, we show that the successful antimicrobial SMs producers belong to Burkholderia s.s. Additionally, we reviewed the occurrence, bioactivities, modes of action, structural, and biosynthetic information of thirty-eight Burkholderia antimicrobial SMs shedding light on their diversity, complexity, and uniqueness as well as the importance of genome-guided strategies to facilitate their discovery. Several Burkholderia NRPS and PKS display unusual features, which are reflected in their structural diversity, important bioactivities, and varied modes of action. Up to now, it is possible to observe a general tendency of Burkholderia SMs being more active against fungi. Although the modes of action and biosynthetic gene clusters of many SMs remain unknown, we highlight the potential of Burkholderia SMs as alternatives to fight against new diseases and antibiotic resistance.
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Affiliation(s)
- Evelise Bach
- Departamento de Genética and Programa de Pós-graduação em Genética e Biologia Molecular, Instituto de Biociências, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
| | - Luciane Maria Pereira Passaglia
- Departamento de Genética and Programa de Pós-graduação em Genética e Biologia Molecular, Instituto de Biociências, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
| | - Junjing Jiao
- Department for Pharmaceutical Biology, Pharmaceutical Institute, University of Tübingen, Tübingen, Germany
| | - Harald Gross
- Department for Pharmaceutical Biology, Pharmaceutical Institute, University of Tübingen, Tübingen, Germany
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29
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Loss of RND-type multidrug efflux pumps triggers iron starvation and lipid A modifications in Pseudomonas aeruginosa. Antimicrob Agents Chemother 2021; 65:e0059221. [PMID: 34252310 DOI: 10.1128/aac.00592-21] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Transporters belonging to the Resistance-Nodulation-Division (RND) superfamily of proteins are invariably present in the genomes of Gram-negative bacteria and are largely responsible for the intrinsic antibiotic resistance of these organisms. The number of genes encoding RND transporters per genome vary from one to sixteen and correlates with environmental versatilities of bacterial species. Pseudomonas aeruginosa PAO1 strain, a ubiquitous nosocomial pathogen, possesses twelve RND pumps, which are implicated in development of clinical multidrug resistance and known to contribute to virulence, quorum sensing and many other physiological functions. In this study, we analyzed how P. aeruginosa physiology adapts to the lack of RND-mediated efflux activities. A combination of transcriptomics, metabolomics, genetic and analytical approaches showed that the P. aeruginosa PΔ6 strain lacking six best characterized RND pumps activates a specific adaptation response that involves significant changes in abundance and activities of several transport systems, quorum sensing, iron acquisition and lipid A modifications. Our results demonstrate that these cells accumulate large quantities of pseudomonas quorum signal (PQS), which triggers iron starvation and activation of siderophore biosynthesis and acquisition pathways. The accumulation of iron in turn activates lipid A modification and membrane protection pathways. A transcriptionally regulated RND pump MuxABC-OpmB contributes to these transformations by controlling concentrations of coumarins. Our results suggest that these changes reduce the permeability barrier of the outer membrane and are needed to protect the cell envelope of efflux-deficient P. aeruginosa.
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30
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Dow L. How Do Quorum-Sensing Signals Mediate Algae-Bacteria Interactions? Microorganisms 2021; 9:microorganisms9071391. [PMID: 34199114 PMCID: PMC8307130 DOI: 10.3390/microorganisms9071391] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2021] [Revised: 06/11/2021] [Accepted: 06/15/2021] [Indexed: 11/16/2022] Open
Abstract
Quorum sensing (QS) describes a process by which bacteria can sense the local cell density of their own species, thus enabling them to coordinate gene expression and physiological processes on a community-wide scale. Small molecules called autoinducers or QS signals, which act as intraspecies signals, mediate quorum sensing. As our knowledge of QS has progressed, so too has our understanding of the structural diversity of QS signals, along with the diversity of bacteria conducting QS and the range of ecosystems in which QS takes place. It is now also clear that QS signals are more than just intraspecies signals. QS signals mediate interactions between species of prokaryotes, and between prokaryotes and eukaryotes. In recent years, our understanding of QS signals as mediators of algae-bacteria interactions has advanced such that we are beginning to develop a mechanistic understanding of their effects. This review will summarize the recent efforts to understand how different classes of QS signals contribute to the interactions between planktonic microalgae and bacteria in our oceans, primarily N-acyl-homoserine lactones, their degradation products of tetramic acids, and 2-alkyl-4-quinolones. In particular, this review will discuss the ways in which QS signals alter microalgae growth and metabolism, namely as direct effectors of photosynthesis, regulators of the cell cycle, and as modulators of other algicidal mechanisms. Furthermore, the contribution of QS signals to nutrient acquisition is discussed, and finally, how microalgae can modulate these small molecules to dampen their effects.
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Affiliation(s)
- Lachlan Dow
- Root Microbe Interactions Laboratory, Australian National University, Canberra 0200, Australia
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31
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Brown HL, Clayton A, Stephens P. The role of bacterial extracellular vesicles in chronic wound infections: Current knowledge and future challenges. Wound Repair Regen 2021; 29:864-880. [PMID: 34132443 DOI: 10.1111/wrr.12949] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 05/14/2021] [Accepted: 05/26/2021] [Indexed: 12/16/2022]
Abstract
Chronic wounds are a significant global problem with an increasing economic and patient welfare impact. How wounds move from an acute to chronic, non-healing, state is not well understood although it is likely that it is driven by a poorly regulated local inflammatory state. Opportunistic pathogens such as Staphylococcus aureus and Pseudomonas aeruginosa are well known to stimulate a pro-inflammatory response and so their presence may further drive chronicity. Studies have demonstrated that host cell extracellular vesicles (hEVs), in particular exosomes, have multiple roles in both increasing and decreasing chronicity within wounds; however, the role of bacterial extracellular vesicles (bEVs) is still poorly understood. The aim of this review is to evaluate bEV biogenesis and function within chronic wound relevant bacterial species to determine what, if any, role bEVs may have in driving wound chronicity. We determine that bEVs drive chronicity by both increasing persistence of key pathogens such as Staphylococcus aureus and Pseudomonas aeruginosa and stimulating a pro-inflammatory response by the host. Data also suggest that both bEVs and hEVs show therapeutic promise, providing vaccine candidates, decoy targets for bacterial toxins or modulating the bacterial species within chronic wound biofilms. Caution should, however, be used when interpreting findings to date as the bEV field is still in its infancy and as such lacks consistency in bEV isolation and characterization. It is of primary importance that this is addressed, allowing meaningful conclusions to be drawn and increasing reproducibility within the field.
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Affiliation(s)
- Helen L Brown
- School of Dentistry, Cardiff University, Cardiff, UK
| | - Aled Clayton
- Division of Cancer & Genetics, School of Medicine, Cardiff, UK
| | - Phil Stephens
- School of Dentistry, Cardiff University, Cardiff, UK
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32
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Vasseur-Coronado M, Vlassi A, du Boulois HD, Schuhmacher R, Parich A, Pertot I, Puopolo G. Ecological Role of Volatile Organic Compounds Emitted by Pantoea agglomerans as Interspecies and Interkingdom Signals. Microorganisms 2021; 9:microorganisms9061186. [PMID: 34072820 PMCID: PMC8229667 DOI: 10.3390/microorganisms9061186] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 05/22/2021] [Accepted: 05/29/2021] [Indexed: 12/28/2022] Open
Abstract
Volatile organic compounds (VOCs) play an essential role in microbe–microbe and plant–microbe interactions. We investigated the interaction between two plant growth-promoting rhizobacteria, and their interaction with tomato plants. VOCs produced by Pantoea agglomerans MVC 21 modulates the release of siderophores, the solubilisation of phosphate and potassium by Pseudomonas (Ps.) putida MVC 17. Moreover, VOCs produced by P. agglomerans MVC 21 increased lateral root density (LRD), root and shoot dry weight of tomato seedlings. Among the VOCs released by P. agglomerans MVC 21, only dimethyl disulfide (DMDS) showed effects similar to P. agglomerans MVC 21 VOCs. Because of the effects on plants and bacterial cells, we investigated how P. agglomerans MVC 21 VOCs might influence bacteria–plant interaction. Noteworthy, VOCs produced by P. agglomerans MVC 21 boosted the ability of Ps. putida MVC 17 to increase LRD and root dry weight of tomato seedlings. These results could be explained by the positive effect of DMDS and P. agglomerans MVC 21 VOCs on acid 3-indoleacetic production in Ps. putida MVC 17. Overall, our results clearly indicated that P. agglomerans MVC 21 is able to establish a beneficial interaction with Ps. putida MVC 17 and tomato plants through the emission of DMDS.
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Affiliation(s)
- Maria Vasseur-Coronado
- Research and Innovation Centre, Department of Sustainable Agro-Ecosystems and Bioresources, Fondazione Edmund Mach, Via E. Mach 1, 38098 San Michele all’Adige, Italy; (M.V.-C.); (I.P.)
- Department of Civil, Environmental and Mechanical Engineering, University of Trento, via Mesiano 77, 38123 Trento, Italy
- De Ceuster Meststoffen NV (DCM), Bannerlaan 79, 2280 Grobbendonk, Belgium;
- Scientia Terrae Research Institute, Fortsesteenweg 30A, 2860 Sint-Katelijne-Waver, Belgium
| | - Anthi Vlassi
- Department of Agrobiotechnology (IFA-Tulln), Institute of Bioanalytics and Agro-Metabolomics, University of Natural Resources and Life Sciences, Vienna (BOKU), Konrad-Lorenz Straße 20, 3430 Tulln, Austria; (A.V.); (R.S.); (A.P.)
| | | | - Rainer Schuhmacher
- Department of Agrobiotechnology (IFA-Tulln), Institute of Bioanalytics and Agro-Metabolomics, University of Natural Resources and Life Sciences, Vienna (BOKU), Konrad-Lorenz Straße 20, 3430 Tulln, Austria; (A.V.); (R.S.); (A.P.)
| | - Alexandra Parich
- Department of Agrobiotechnology (IFA-Tulln), Institute of Bioanalytics and Agro-Metabolomics, University of Natural Resources and Life Sciences, Vienna (BOKU), Konrad-Lorenz Straße 20, 3430 Tulln, Austria; (A.V.); (R.S.); (A.P.)
| | - Ilaria Pertot
- Research and Innovation Centre, Department of Sustainable Agro-Ecosystems and Bioresources, Fondazione Edmund Mach, Via E. Mach 1, 38098 San Michele all’Adige, Italy; (M.V.-C.); (I.P.)
- Center Agriculture Food Environment (C3A), University of Trento, via E. Mach 1, 38098 San Michele all’Adige, Italy
| | - Gerardo Puopolo
- Research and Innovation Centre, Department of Sustainable Agro-Ecosystems and Bioresources, Fondazione Edmund Mach, Via E. Mach 1, 38098 San Michele all’Adige, Italy; (M.V.-C.); (I.P.)
- Center Agriculture Food Environment (C3A), University of Trento, via E. Mach 1, 38098 San Michele all’Adige, Italy
- Correspondence:
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33
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Nazik H, Sass G, Williams P, Déziel E, Stevens DA. Molecular Modifications of the Pseudomonas Quinolone Signal in the Intermicrobial Competition with Aspergillus. J Fungi (Basel) 2021; 7:jof7050343. [PMID: 33925067 PMCID: PMC8146305 DOI: 10.3390/jof7050343] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 04/20/2021] [Accepted: 04/21/2021] [Indexed: 02/03/2023] Open
Abstract
The Pseudomonas quinolone signal (PQS) is an important quorum-sensing molecule for Pseudomonas aeruginosa that regulates virulence factors, chelates iron, and is an important factor in interactions with eukaryotes, including fungi and mammalian hosts. It was previously shown to inhibit or boost Aspergillus, depending on the milieu iron concentration. We studied several molecular modifications of the PQS molecule, and their effects on Aspergillus biofilm metabolism and growth in vitro, and the effects of iron supplementation. We found that most molecules inhibited Aspergillus at concentrations similar to that of PQS, but with relatively flat dose-responses, and all were less potent than PQS. The inhibition was reversible by iron, suggesting interference with fungal iron metabolism. Stimulation of Aspergillus was not noted. We conclude that the critical Aspergillus-inhibiting moeities of the PQS molecule were partially, but not completely, interfered with by molecular modifications at several sites on the PQS molecule. The mechanism, as with PQS, appears to relate to fungal iron metabolism.
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Affiliation(s)
- Hasan Nazik
- Infectious Diseases Research Laboratory, California Institute for Medical Research, San Jose, CA 95128, USA; (H.N.); (G.S.)
| | - Gabriele Sass
- Infectious Diseases Research Laboratory, California Institute for Medical Research, San Jose, CA 95128, USA; (H.N.); (G.S.)
| | - Paul Williams
- Biodiscovery Institute and School of Life Sciences, University of Nottingham, Nottingham NG7 2RD, UK;
| | - Eric Déziel
- Centre Armand-Frappier Santé Biotechnologie, Institut National de la Recherche Scientifique (INRS), Laval, QC H7V 1B7, Canada;
| | - David A. Stevens
- Infectious Diseases Research Laboratory, California Institute for Medical Research, San Jose, CA 95128, USA; (H.N.); (G.S.)
- Division of Infectious Diseases and Geographic Medicine, Stanford University Medical School, Stanford, CA 94305, USA
- Correspondence: ; Tel.: +1-408-998-4554
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34
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An Antifungal Polycyclic Tetramate Macrolactam, Heat-Stable Antifungal Factor (HSAF), Is a Novel Oxidative Stress Modulator in Lysobacter enzymogenes. Appl Environ Microbiol 2021; 87:AEM.03105-20. [PMID: 33712422 DOI: 10.1128/aem.03105-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 03/02/2021] [Indexed: 01/19/2023] Open
Abstract
Polycyclic tetramate macrolactams (PoTeMs) are a fast-growing family of antibiotic natural products found in phylogenetically diverse microorganisms. Surprisingly, none of the PoTeMs have been investigated for potential physiological functions in their producers. Here, we used heat-stable antifungal factor (HSAF), an antifungal PoTeM from Lysobacter enzymogenes, as a model to show that PoTeMs form complexes with iron ions, with an association constant (Ka ) of 2.71 × 106 M-1 The in vivo and in vitro data showed formation of 2:1 and 3:1 complexes between HSAF and iron ions, which were confirmed by molecular mechanical and quantum mechanical calculations. HSAF protected DNA from degradation in high concentrations of iron and H2O2 or under UV radiation. HSAF mutants of L. enzymogenes barely survived under oxidative stress and exhibited markedly increased production of reactive oxygen species (ROS). Exogenous addition of HSAF into the mutants significantly prevented ROS production and restored normal growth in the mutants under the oxidative stress. The results reveal that the function of HSAF is to protect the producer microorganism from oxidative damage rather than as an iron-acquisition siderophore. The characteristic structure of PoTeMs, a 2,4-pyrrolidinedione-embedded macrolactam, may represent a new iron-chelating scaffold of microbial metabolites. The study demonstrated a previously unrecognized strategy for microorganisms to modulate oxidative damage to the cells.IMPORTANCE PoTeMs are a family of structurally distinct metabolites that have been found in a large number of bacteria. Although PoTeMs exhibit diverse therapeutic properties, the physiological function of PoTeMs in the producer microorganisms had not been investigated. HSAF from Lysobacter enzymogenes is an antifungal PoTeM that has been subjected to extensive studies for mechanisms of biosynthesis, regulation, and antifungal activity. Using HSAF as a model system, we here showed that the characteristic structure of PoTeMs, a 2,4-pyrrolidinedione-embedded macrolactam, may represent a new iron-chelating scaffold of microbial metabolites. In L. enzymogenes, HSAF functions as a small-molecule modulator for oxidative damage caused by iron, H2O2, and UV light. Together, the study demonstrated a previously unrecognized strategy for microorganisms to modulate oxidative damage to the cells. HSAF represents the first member of the fast-growing PoTeM family of microbial metabolites whose potential biological function has been studied.
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35
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Elmassry MM, Bisht K, Colmer-Hamood JA, Wakeman CA, San Francisco MJ, Hamood AN. Malonate utilization by Pseudomonas aeruginosa affects quorum-sensing and virulence and leads to formation of mineralized biofilm-like structures. Mol Microbiol 2021; 116:516-537. [PMID: 33892520 DOI: 10.1111/mmi.14729] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 04/06/2021] [Accepted: 04/16/2021] [Indexed: 01/02/2023]
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that uses malonate among its many carbon sources. We recently reported that, when grown in blood from trauma patients, P. aeruginosa expression of malonate utilization genes was upregulated. In this study, we explored the role of malonate utilization and its contribution to P. aeruginosa virulence. We grew P. aeruginosa strain PA14 in M9 minimal medium containing malonate (MM9) or glycerol (GM9) as a sole carbon source and assessed the effect of the growth on quorum sensing, virulence factors, and antibiotic resistance. Growth of PA14 in MM9, compared to GM9, reduced the production of elastases, rhamnolipids, and pyoverdine; enhanced the production of pyocyanin and catalase; and increased its sensitivity to norfloxacin. Growth in MM9 decreased extracellular levels of N-acylhomoserine lactone autoinducers, an effect likely associated with increased pH of the culture medium; but had little effect on extracellular levels of PQS. At 18 hr of growth in MM9, PA14 formed biofilm-like structures or aggregates that were associated with biomineralization, which was related to increased pH of the culture medium. These results suggest that malonate significantly impacts P. aeruginosa pathogenesis by influencing the quorum sensing systems, the production of virulence factors, biofilm formation, and antibiotic resistance.
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Affiliation(s)
- Moamen M Elmassry
- Department of Biological Sciences, Texas Tech University, Lubbock, TX, USA
| | - Karishma Bisht
- Department of Biological Sciences, Texas Tech University, Lubbock, TX, USA
| | - Jane A Colmer-Hamood
- Department of Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, TX, USA.,Department of Medical Education, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | | | - Michael J San Francisco
- Department of Biological Sciences, Texas Tech University, Lubbock, TX, USA.,Honors College, Texas Tech University, Lubbock, TX, USA
| | - Abdul N Hamood
- Department of Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, TX, USA.,Department of Surgery, Texas Tech University Health Sciences Center, Lubbock, TX, USA
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36
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The involvement of PacIRA system of Stenotrophomonas maltophilia in the uptake of Pseudomonas aeruginosa pyochelin and intraspecies competition for iron acquisition. JOURNAL OF MICROBIOLOGY, IMMUNOLOGY, AND INFECTION = WEI MIAN YU GAN RAN ZA ZHI 2021; 55:273-281. [PMID: 33811013 DOI: 10.1016/j.jmii.2021.03.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 03/03/2021] [Indexed: 11/22/2022]
Abstract
BACKGROUND Stenotrophomonas maltophilia, a species of highly genetic diversity, has emerged as an important nosocomial pathogen. S. maltophilia and Pseudomonas aeruginosa are often co-isolated from pneumonia patients. In our previous study, we have demonstrated that the pacIRA cluster present in some but not all clinical S. maltophilia isolates. Proteins encoded by pacIRA operon are an extracytoplasmic function (ECF) sigma factor, a transmembrane anti-sigma regulator, and a TonB-dependent receptor. This study aimed to elucidate PacIRA system function and its significance to S. maltophilia. METHODS The pacI, pacR, and pacA genes were individually or totally deleted from the chromosome of KJΔEnt, a pacIRA-positive and siderophore-null strain. Growth promotion assay was performed to examine the implication of pacIRA system in iron utilization. Gene expression was quantified by quantitative real time PCR (qRT-PCR). Growth competition assay was executed to investigate the significance of pacIRA operon to S. maltophilia. RESULTS PacIRA system contributed to utilize ferri-pyochelin of P. aeruginosa as iron sources for growth in an iron-depleted condition, but hardly utilized ferric citrate, hemin, ferri-stenobactin, and ferri-pyoverdine. PacIRA was founded to belong to Fur regulon and upregulated in response to iron-depleted stress. Growth competition assay demonstrated that pacIRA-positive S. maltophilia had a superiority over pacIRA-negative S. maltophilia in iron acquisition when they were co-cultured in P. aeruginosa ferri-pyochelin-supplemented medium. CONCLUSIONS PacIRA system of S. maltophilia is a xenosiderophore uptake implement, involving in the acquisition of pyochelin of P. aeruginosa.
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Avila-Calderón ED, Ruiz-Palma MDS, Aguilera-Arreola MG, Velázquez-Guadarrama N, Ruiz EA, Gomez-Lunar Z, Witonsky S, Contreras-Rodríguez A. Outer Membrane Vesicles of Gram-Negative Bacteria: An Outlook on Biogenesis. Front Microbiol 2021; 12:557902. [PMID: 33746909 PMCID: PMC7969528 DOI: 10.3389/fmicb.2021.557902] [Citation(s) in RCA: 77] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 02/04/2021] [Indexed: 12/14/2022] Open
Abstract
Outer membrane vesicles (OMVs) from Gram-negative bacteria were first described more than 50 years ago. However, the molecular mechanisms involved in biogenesis began to be studied only in the last few decades. Presently, the biogenesis and molecular mechanisms for their release are not completely known. This review covers the most recent information on cellular components involved in OMV biogenesis, such as lipoproteins and outer membrane proteins, lipopolysaccharide, phospholipids, quorum-sensing molecules, and flagella.
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Affiliation(s)
- Eric Daniel Avila-Calderón
- Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, México City, Mexico.,Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados, Instituto Politécnico Nacional, CINVESTAV-IPN, México City, Mexico
| | - María Del Socorro Ruiz-Palma
- Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, México City, Mexico.,División Químico Biológicas, Universidad Tecnológica de Tecámac, Tecámac, Mexico
| | - Ma Guadalupe Aguilera-Arreola
- Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, México City, Mexico
| | - Norma Velázquez-Guadarrama
- Unidad de Investigación en enfermedades infecciosas, Hospital Infantil de México Federico Gómez, Ciudad de México, Mexico
| | - Enrico A Ruiz
- Departamento de Zoología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, México City, Mexico
| | - Zulema Gomez-Lunar
- Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, México City, Mexico
| | - Sharon Witonsky
- Center for One Health Research, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, United States.,Large Animal Clinical Sciences, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, United States
| | - Araceli Contreras-Rodríguez
- Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, México City, Mexico
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Influence of relevant cystic fibrosis bacteria on Scedosporium apiospermum and Scedosporium boydii growth and viability. Braz J Microbiol 2021; 52:185-193. [PMID: 33442865 DOI: 10.1007/s42770-020-00415-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Accepted: 12/18/2020] [Indexed: 10/22/2022] Open
Abstract
Cystic fibrosis (CF) causes a variety of symptoms in different organs, but the majority of the morbidity and mortality of CF is related with pulmonary conditions. Primary infections are usually bacterial, and when treated with antibiotics, yeast infections appear or become more evident. Studies show that different microorganisms can co-inhabit the same environment and the interactions could be synergistic or antagonistic. Using techniques including viable and non-viable cell-to-cell interactions, mixed culture in liquid, and solid media sharing or not the supernatant, this study has evaluated interactions between the fungal species Scedosporium apiospermum and Scedosporium boydii with the bacterial species Staphylococcus aureus, Pseudomonas aeruginosa, and Burkholderia cepacia. Cell-to-cell interactions in liquid medium showed that P. aeruginosa and B. cepacia were able to reduce fungal viability but only in the presence of alive bacteria. Interactions without cell contact using a semi-permeable membrane showed that all bacteria were able to inhibit both fungal growths/viabilities. Cell-free supernatants from bacterial growth reduced fungal viability in planktonic fungal cells as well as in some conditions for preformed fungal biomass. According to the chemical analysis of the bacterial supernatants, the predominant component is protein. In this work, we verified that bacterial cells and their metabolites, present in the supernatants, can play anti-S. apiospermum and anti-S. boydii roles on fungal growth and viability.
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Mozaheb N, Mingeot-Leclercq MP. Membrane Vesicle Production as a Bacterial Defense Against Stress. Front Microbiol 2020; 11:600221. [PMID: 33362747 PMCID: PMC7755613 DOI: 10.3389/fmicb.2020.600221] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 11/16/2020] [Indexed: 12/15/2022] Open
Abstract
Membrane vesicles are the nano-sized vesicles originating from membranes. The production of membrane vesicles is a common feature among bacteria. Depending on the bacterial growth phase and environmental conditions, membrane vesicles show diverse characteristics. Various physiological and ecological roles have been attributed to membrane vesicles under both homeostatic and stressful conditions. Pathogens encounter several stressors during colonization in the hostile environment of host tissues. Nutrient deficiency, the presence of antibiotics as well as elements of the host’s immune system are examples of stressors threatening pathogens inside their host. To combat stressors and survive, pathogens have established various defensive mechanisms, one of them is production of membrane vesicles. Pathogens produce membrane vesicles to alleviate the destructive effects of antibiotics or other types of antibacterial treatments. Additionally, membrane vesicles can also provide benefits for the wider bacterial community during infections, through the transfer of resistance or virulence factors. Hence, given that membrane vesicle production may affect the activities of antibacterial agents, their production should be considered when administering antibacterial treatments. Besides, regarding that membrane vesicles play vital roles in bacteria, disrupting their production may suggest an alternative strategy for battling against pathogens. Here, we aim to review the stressors encountered by pathogens and shed light on the roles of membrane vesicles in increasing pathogen adaptabilities in the presence of stress-inducing factors.
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Affiliation(s)
- Negar Mozaheb
- Université catholique de Louvain (UCL), Louvain Drug Research Institute (LDRI), Cellular & Molecular Pharmacology Unit (FACM), Brussels, Belgium
| | - Marie-Paule Mingeot-Leclercq
- Université catholique de Louvain (UCL), Louvain Drug Research Institute (LDRI), Cellular & Molecular Pharmacology Unit (FACM), Brussels, Belgium
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Baldelli V, D’Angelo F, Pavoncello V, Fiscarelli EV, Visca P, Rampioni G, Leoni L. Identification of FDA-approved antivirulence drugs targeting the Pseudomonas aeruginosa quorum sensing effector protein PqsE. Virulence 2020; 11:652-668. [PMID: 32423284 PMCID: PMC7549961 DOI: 10.1080/21505594.2020.1770508] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 04/03/2020] [Accepted: 05/05/2020] [Indexed: 12/13/2022] Open
Abstract
The ability of the bacterial pathogen Pseudomonas aeruginosa to cause both chronic and acute infections mainly relies on its capacity to finely modulate the expression of virulence factors through a complex network of regulatory circuits, including the pqs quorum sensing (QS) system. While in most QS systems the signal molecule/receptor complexes act as global regulators that modulate the expression of QS-controlled genes, the main effector protein of the pqs system is PqsE. This protein is involved in the synthesis of the QS signal molecules 2-alkyl-4(1H)-quinolones (AQs), but it also modulates the expression of genes involved in virulence factors production and biofilm formation via AQ-independent pathway(s). P. aeruginosa pqsE mutants disclose attenuated virulence in plant and animal infection models, hence PqsE is considered a good target for the development of antivirulence drugs against P. aeruginosa. In this study, the negative regulation exerted by PqsE on its own transcription has been exploited to develop a screening system for the identification of PqsE inhibitors in a library of FDA-approved drugs. This led to the identification of nitrofurazone and erythromycin estolate, two antibiotic compounds that reduce the expression of PqsE-dependent virulence traits and biofilm formation in the model strain P. aeruginosa PAO1 at concentrations far below those affecting the bacterial growth rate. Notably, both drugs reduce the production of the PqsE-controlled virulence factor pyocyanin also in P. aeruginosa strains isolated from cystic fibrosis patients, and do not antagonize the activity of antibiotics commonly used to treat P. aeruginosa infection.
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Affiliation(s)
| | | | | | | | - Paolo Visca
- Department of Science, University Roma Tre, Rome, Italy
| | | | - Livia Leoni
- Department of Science, University Roma Tre, Rome, Italy
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Cooke AC, Florez C, Dunshee EB, Lieber AD, Terry ML, Light CJ, Schertzer JW. Pseudomonas Quinolone Signal-Induced Outer Membrane Vesicles Enhance Biofilm Dispersion in Pseudomonas aeruginosa. mSphere 2020; 5:e01109-20. [PMID: 33239369 PMCID: PMC7690959 DOI: 10.1128/msphere.01109-20] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 11/08/2020] [Indexed: 01/15/2023] Open
Abstract
Bacterial biofilms are major contributors to chronic infections in humans. Because they are recalcitrant to conventional therapy, they present a particularly difficult treatment challenge. Identifying factors involved in biofilm development can help uncover novel targets and guide the development of antibiofilm strategies. Pseudomonas aeruginosa causes surgical site, burn wound, and hospital-acquired infections and is also associated with aggressive biofilm formation in the lungs of cystic fibrosis patients. A potent but poorly understood contributor to P. aeruginosa virulence is the ability to produce outer membrane vesicles (OMVs). OMV trafficking has been associated with cell-cell communication, virulence factor delivery, and transfer of antibiotic resistance genes. Because OMVs have almost exclusively been studied using planktonic cultures, little is known about their biogenesis and function in biofilms. Several groups have shown that Pseudomonas quinolone signal (PQS) induces OMV formation in P. aeruginosa Our group described a biophysical mechanism for this and recently showed it is operative in biofilms. Here, we demonstrate that PQS-induced OMV production is highly dynamic during biofilm development. Interestingly, PQS and OMV synthesis are significantly elevated during dispersion compared to attachment and maturation stages. PQS biosynthetic and receptor mutant biofilms were significantly impaired in their ability to disperse, but this phenotype was rescued by genetic complementation or exogenous addition of PQS. Finally, we show that purified OMVs can actively degrade extracellular protein, lipid, and DNA. We therefore propose that enhanced production of PQS-induced OMVs during biofilm dispersion facilitates cell escape by coordinating the controlled degradation of biofilm matrix components.IMPORTANCE Treatments that manipulate biofilm dispersion hold the potential to convert chronic drug-tolerant biofilm infections from protected sessile communities into released populations that are orders-of-magnitude more susceptible to antimicrobial treatment. However, dispersed cells often exhibit increased acute virulence and dissemination phenotypes. A thorough understanding of the dispersion process is therefore critical before this promising strategy can be effectively employed. Pseudomonas quinolone signal (PQS) has been implicated in early biofilm development, but we hypothesized that its function as an outer membrane vesicle (OMV) inducer may contribute at multiple stages. Here, we demonstrate that PQS and OMVs are differentially produced during Pseudomonas aeruginosa biofilm development and provide evidence that effective biofilm dispersion is dependent on the production of PQS-induced OMVs, which likely act as delivery vehicles for matrix-degrading enzymes. These findings lay the groundwork for understanding OMV contributions to biofilm development and suggest a model to explain the controlled matrix degradation that accompanies biofilm dispersion in many species.
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Affiliation(s)
- Adam C Cooke
- Department of Biological Sciences, Binghamton University, Binghamton, New York, USA
- Binghamton Biofilm Research Center, Binghamton University, Binghamton, New York, USA
| | - Catalina Florez
- Department of Biological Sciences, Binghamton University, Binghamton, New York, USA
- Binghamton Biofilm Research Center, Binghamton University, Binghamton, New York, USA
| | - Elise B Dunshee
- Department of Biological Sciences, Binghamton University, Binghamton, New York, USA
- Binghamton Biofilm Research Center, Binghamton University, Binghamton, New York, USA
| | - Avery D Lieber
- Department of Biological Sciences, Binghamton University, Binghamton, New York, USA
- First-year Research Immersion Program, Binghamton University, Binghamton, New York, USA
| | - Michelle L Terry
- Department of Biological Sciences, Binghamton University, Binghamton, New York, USA
- First-year Research Immersion Program, Binghamton University, Binghamton, New York, USA
| | - Caitlin J Light
- Department of Biological Sciences, Binghamton University, Binghamton, New York, USA
- Binghamton Biofilm Research Center, Binghamton University, Binghamton, New York, USA
- First-year Research Immersion Program, Binghamton University, Binghamton, New York, USA
- Summer Research Immersion Program, Binghamton University, Binghamton, New York, USA
| | - Jeffrey W Schertzer
- Department of Biological Sciences, Binghamton University, Binghamton, New York, USA
- Binghamton Biofilm Research Center, Binghamton University, Binghamton, New York, USA
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Burkholderia thailandensis Methylated Hydroxyalkylquinolines: Biosynthesis and Antimicrobial Activity in Cocultures. Appl Environ Microbiol 2020; 86:AEM.01452-20. [PMID: 33008823 DOI: 10.1128/aem.01452-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 09/15/2020] [Indexed: 02/04/2023] Open
Abstract
The bacterium Burkholderia thailandensis produces an arsenal of secondary metabolites that have diverse structures and roles in the ecology of this soil-dwelling bacterium. In coculture experiments, B. thailandensis strain E264 secretes an antimicrobial that nearly eliminates another soil bacterium, Bacillus subtilis strain 168. To identify the antimicrobial, we used a transposon mutagenesis approach. This screen identified antimicrobial-defective mutants with insertions in the hmqA, hmqC, and hmqF genes involved in biosynthesis of a family of 2-alkyl-4(1H)-quinolones called 4-hydroxy-3-methyl-2-alkenylquinolines (HMAQs), which are closely related to the Pseudomonas aeruginosa 4-hydroxy-2-alkylquinolines (HAQs). Insertions also occurred in the previously uncharacterized gene BTH_II1576 ("hmqL"). The results confirm that BTH_II1576 is involved in generating N-oxide derivatives of HMAQs (HMAQ-NOs). Synthetic HMAQ-NO is active against B. subtilis 168, showing ∼50-fold more activity than HMAQ. Both the methyl group and the length of the carbon side chain account for the high activity of HMAQ-NO. The results provide new information on the biosynthesis and activities of HMAQs and reveal new insight into how these molecules might be important for the ecology of B. thailandensis IMPORTANCE The soil bacterium Burkholderia thailandensis produces 2-alkyl-4(1H)-quinolones that are mostly methylated 4-hydroxyalkenylquinolines, a family of relatively unstudied metabolites similar to molecules also synthesized by Pseudomonas aeruginosa Several of the methylated 4-hydroxyalkenylquinolines have antimicrobial activity against other species. We show that Bacillus subtilis strain 168 is particularly susceptible to N-oxidated methylalkenylquinolines (HMAQ-NOs). We confirmed that HMAQ-NO biosynthesis requires the previously unstudied protein HmqL. These results provide new information about the biology of 2-alkyl-4(1H)-quinolones, particularly the methylated 4-hydroxyalkenylquinolines, which are unique to B. thailandensis This study also has importance for understanding B. thailandensis secondary metabolites and has implications for potential therapeutic development.
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Static Growth Promotes PrrF and 2-Alkyl-4(1 H)-Quinolone Regulation of Type VI Secretion Protein Expression in Pseudomonas aeruginosa. J Bacteriol 2020; 202:JB.00416-20. [PMID: 33020221 DOI: 10.1128/jb.00416-20] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 09/29/2020] [Indexed: 12/21/2022] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that is frequently associated with both acute and chronic infections. P. aeruginosa possesses a complex regulatory network that modulates nutrient acquisition and virulence, but our knowledge of these networks is largely based on studies with shaking cultures, which are not likely representative of conditions during infection. Here, we provide proteomic, metabolic, and genetic evidence that regulation by iron, a critical metallonutrient, is altered in static P. aeruginosa cultures. Specifically, we observed a loss of iron-induced expression of proteins for oxidative phosphorylation, tricarboxylic acid (TCA) cycle metabolism under static conditions. Moreover, we identified type VI secretion as a target of iron regulation in P. aeruginosa cells under static but not shaking conditions, and we present evidence that this regulation occurs via PrrF small regulatory RNA (sRNA)-dependent production of 2-alkyl-4(1H)-quinolone metabolites. These results yield new iron regulation paradigms in an important opportunistic pathogen and highlight the need to redefine iron homeostasis in static microbial communities.IMPORTANCE Host-mediated iron starvation is a broadly conserved signal for microbial pathogens to upregulate expression of virulence traits required for successful infection. Historically, global iron regulatory studies in microorganisms have been conducted in shaking cultures to ensure culture homogeneity, yet these conditions are likely not reflective of growth during infection. Pseudomonas aeruginosa is a well-studied opportunistic pathogen and model organism for iron regulatory studies. Iron homeostasis is maintained through the Fur protein and PrrF small regulatory sRNAs, the functions of which are highly conserved in many other bacterial species. In the current study, we examined how static growth affects the known iron and PrrF regulons of P. aeruginosa, leading to the discovery of novel PrrF-regulated virulence processes. This study demonstrates how the utilization of distinct growth models can enhance our understanding of basic physiological processes that may also affect pathogenesis.
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Targeted and untargeted quantification of quorum sensing signalling molecules in bacterial cultures and biological samples via HPLC-TQ MS techniques. Anal Bioanal Chem 2020; 413:853-864. [PMID: 33206214 PMCID: PMC7809007 DOI: 10.1007/s00216-020-03040-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 10/09/2020] [Accepted: 10/30/2020] [Indexed: 02/06/2023]
Abstract
Quorum sensing (QS) is the ability of some bacteria to detect and to respond to population density through signalling molecules. QS molecules are involved in motility and cell aggregation mechanisms in diseases such as sepsis. Few biomarkers are currently available to diagnose sepsis, especially in high-risk conditions. The aim of this study was the development of new analytical methods based on liquid chromatography-mass spectrometry for the detection and quantification of QS signalling molecules, including N-acyl homoserine lactones (AHL) and hydroxyquinolones (HQ), in biofluids. Biological samples used in the study were Pseudomonas aeruginosa bacterial cultures and plasma from patients with sepsis. We developed two MS analytical methods, based on neutral loss (NL) and product ion (PI) experiments, to identify and characterize unknown AHL and HQ molecules. We then established a multiple-reaction-monitoring (MRM) method to quantify specific QS compounds. We validated the HPLC-MS-based approaches (MRM-NL-PI), and data were in accord with the validation guidelines. With the NL and PI MS-based methods, we identified and characterized 3 and 13 unknown AHL and HQ compounds, respectively, in biological samples. One of the newly found AHL molecules was C12-AHL, first quantified in Pseudomonas aeruginosa bacterial cultures. The MRM quantitation of analytes in plasma from patients with sepsis confirmed the analytical ability of MRM for the quantification of virulence factors during sepsis. Graphical abstract ![]()
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Beasley KL, Cristy SA, Elmassry MM, Dzvova N, Colmer-Hamood JA, Hamood AN. During bacteremia, Pseudomonas aeruginosa PAO1 adapts by altering the expression of numerous virulence genes including those involved in quorum sensing. PLoS One 2020; 15:e0240351. [PMID: 33057423 PMCID: PMC7561203 DOI: 10.1371/journal.pone.0240351] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 09/24/2020] [Indexed: 12/17/2022] Open
Abstract
Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen that produces numerous virulence factors and causes serious infections in trauma patients and patients with severe burns. We previously showed that the growth of P. aeruginosa in blood from severely burned or trauma patients altered the expression of numerous genes. However, the specific influence of whole blood from healthy volunteers on P. aeruginosa gene expression is not known. Transcriptome analysis of P. aeruginosa grown for 4 h in blood from healthy volunteers compared to that when grown in laboratory medium revealed that the expression of 1085 genes was significantly altered. Quorum sensing (QS), QS-related, and pyochelin synthesis genes were downregulated, while genes of the type III secretion system and those for pyoverdine synthesis were upregulated. The observed effect on the QS and QS-related genes was shown to reside within serum fraction: growth of PAO1 in the presence of 10% human serum from healthy volunteers significantly reduced the expression of QS and QS-regulated genes at 2 and 4 h of growth but significantly enhanced their expression at 8 h. Additionally, the production of QS-regulated virulence factors, including LasA and pyocyanin, was also influenced by the presence of human serum. Serum fractionation experiments revealed that part of the observed effect resides within the serum fraction containing <10-kDa proteins. Growth in serum reduced the production of many PAO1 outer membrane proteins but enhanced the production of others including OprF, a protein previously shown to play a role in the regulation of QS gene expression. These results suggest that factor(s) within human serum: 1) impact P. aeruginosa pathogenesis by influencing the expression of different genes; 2) differentially regulate the expression of QS and QS-related genes in a growth phase- or time-dependent mechanism; and 3) manipulate the production of P. aeruginosa outer membrane proteins.
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Affiliation(s)
- Kellsie L. Beasley
- Department of Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, Texas, Untied States of America
| | - Shane A. Cristy
- Honors College, Texas Tech University, Lubbock, Texas, Untied States of America
| | - Moamen M. Elmassry
- Department of Biological Sciences, Texas Tech University, Lubbock, Texas, Untied States of America
| | - Nyaradzo Dzvova
- Department of Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, Texas, Untied States of America
| | - Jane A. Colmer-Hamood
- Department of Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, Texas, Untied States of America
- Department of Medical Education, Texas Tech University Health Sciences Center, Lubbock, Texas, Untied States of America
| | - Abdul N. Hamood
- Department of Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, Texas, Untied States of America
- Department of Surgery, Texas Tech University Health Sciences Center, Lubbock, Texas, Untied States of America
- * E-mail:
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Zhang Y, Pan X, Wang L, Chen L. Iron metabolism in Pseudomonas aeruginosa biofilm and the involved iron-targeted anti-biofilm strategies. J Drug Target 2020; 29:249-258. [PMID: 32969723 DOI: 10.1080/1061186x.2020.1824235] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Pseudomonas aeruginosa is a gram-negative bacterium that exists in various ecosystems, causing severe infections in patients with AIDS or cystic fibrosis. P. aeruginosa can form biofilm on a variety of surfaces, whereby the bacteria produce defensive substances and enhance antibiotic-resistance, making themselves more adaptable to hostile environments. P. aeruginosa resistance represents one of the main causes of infection-related morbidity and mortality at a global level. Iron is required for the growth of P. aeruginosa biofilm. This review summarises how the iron metabolism contributes to develop biofilm, and more importantly, it may provide some references for the clinic to achieve novel anti-biofilm therapeutics by targeting iron activities.
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Affiliation(s)
- Yapeng Zhang
- Department of Medical Microbiology, School of Basic Medical Sciences, Central South University, Changsha, China
| | - Xuanhe Pan
- Department of Medical Microbiology, School of Basic Medical Sciences, Central South University, Changsha, China
| | - Linqian Wang
- Department of Clinical Laboratory, Hunan Cancer Hospital, the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, China
| | - Liyu Chen
- Department of Medical Microbiology, School of Basic Medical Sciences, Central South University, Changsha, China
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Iron interferes with quorum sensing-mediated cooperation in Pseudomonas aeruginosa by affecting the expression of ppyR and mexT, in addition to rhlR. J Microbiol 2020; 58:938-944. [PMID: 32997304 DOI: 10.1007/s12275-020-0264-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 07/28/2020] [Accepted: 08/03/2020] [Indexed: 10/23/2022]
Abstract
The stabilization of quorum sensing (QS) is vital for bacterial survival in various environments. Although the mechanisms of QS stabilization in certain conditions have been well studied, the impact of environmental factors has received much less attention. In this study, we show that the supplementation of 25 µM iron in competition experiments and 50 µM in evolution experiments to casein growth cultures significantly increased the possibility of population collapse by affecting elastase production. However, the expression of lasI and lasR remained constant regardless of iron concentration and hence this effect was not through interference with the LasIR circuit, which mainly regulates the secretion of elastase in Pseudomonas aeruginosa. However, the expression of rhlR was significantly inhibited by iron treatment, which could affect the production of elastase. Further, based on both reverse transcription quantitative polymerase chain reaction and gene knock-out assays, we show that iron inhibits the transcription of ppyR and enhances the expression of mexT, both of which decrease elastase production and correspondingly interfere with QS stabilization. Our findings show that environmental factors can affect the genes of QS circuits, interfering with QS stabilization. These findings are not only beneficial in understanding the mechanistic effect of iron on QS stabilization, but also demonstrate the complexity of QS stabilization by linking non-QS-related genes with QS traits.
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Zhang F, Li B, Dong H, Chen M, Yao S, Li J, Zhang H, Liu X, Wang H, Song N, Zhang K, Du N, Xu S, Gu L. YdiV regulates Escherichia coli ferric uptake by manipulating the DNA-binding ability of Fur in a SlyD-dependent manner. Nucleic Acids Res 2020; 48:9571-9588. [PMID: 32813023 PMCID: PMC7515728 DOI: 10.1093/nar/gkaa696] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 07/31/2020] [Accepted: 08/13/2020] [Indexed: 12/19/2022] Open
Abstract
Iron is essential for all bacteria. In most bacteria, intracellular iron homeostasis is tightly regulated by the ferric uptake regulator Fur. However, how Fur activates the iron-uptake system during iron deficiency is not fully elucidated. In this study, we found that YdiV, the flagella gene inhibitor, is involved in iron homeostasis in Escherichia coli. Iron deficiency triggers overexpression of YdiV. High levels of YdiV then transforms Fur into a novel form which does not bind DNA in a peptidyl-prolyl cis-trans isomerase SlyD dependent manner. Thus, the cooperation of YdiV, SlyD and Fur activates the gene expression of iron-uptake systems under conditions of iron deficiency. Bacterial invasion assays also demonstrated that both ydiV and slyD are necessary for the survival and growth of uropathogenic E. coli in bladder epithelial cells. This reveals a mechanism where YdiV not only represses flagella expression to make E. coli invisible to the host immune system, but it also promotes iron acquisition to help E. coli overcome host nutritional immunity.
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Affiliation(s)
- Fengyu Zhang
- State Key Laboratory of Microbial Technology, Shandong University, 72 Binhai Road, Qingdao 266237, P.R. China
| | - Bingqing Li
- Key Laboratory of Rare and Uncommon Diseases, Department of Microbiology, Institute of Basic Medicine, Shandong First Medical University & Shandong Academy of Medical Sciences, 18877 Jingshi Road, Jinan 250062, P.R. China
| | - Hongjie Dong
- State Key Laboratory of Microbial Technology, Shandong University, 72 Binhai Road, Qingdao 266237, P.R. China
| | - Min Chen
- State Key Laboratory of Microbial Technology, Shandong University, 72 Binhai Road, Qingdao 266237, P.R. China
| | - Shun Yao
- School of Life Sciences, Shandong University, 72 Binhai Road, Qingdao 266237, P.R. China
| | - Jingwen Li
- Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, 189 Songling Road, Qingdao 266237, P.R. China
| | - Honghai Zhang
- Key Laboratory of Infection and Immunity of Shandong Province and Department of Immunology, School of Basic Medical Sciences, Shandong University, 44 Wenhuaxi Road, Jinan 250012, P. R. China
| | - Xiangguo Liu
- School of Life Sciences, Shandong University, 72 Binhai Road, Qingdao 266237, P.R. China
| | - Hongwei Wang
- State Key Laboratory of Microbial Technology, Shandong University, 72 Binhai Road, Qingdao 266237, P.R. China
| | - Nannan Song
- Key Laboratory of Rare and Uncommon Diseases, Department of Microbiology, Institute of Basic Medicine, Shandong First Medical University & Shandong Academy of Medical Sciences, 18877 Jingshi Road, Jinan 250062, P.R. China
| | - Kundi Zhang
- State Key Laboratory of Microbial Technology, Shandong University, 72 Binhai Road, Qingdao 266237, P.R. China
| | - Ning Du
- School of Life Sciences, Shandong University, 72 Binhai Road, Qingdao 266237, P.R. China
| | - Sujuan Xu
- State Key Laboratory of Microbial Technology, Shandong University, 72 Binhai Road, Qingdao 266237, P.R. China
| | - Lichuan Gu
- State Key Laboratory of Microbial Technology, Shandong University, 72 Binhai Road, Qingdao 266237, P.R. China
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Sikdar R, Elias M. Quorum quenching enzymes and their effects on virulence, biofilm, and microbiomes: a review of recent advances. Expert Rev Anti Infect Ther 2020; 18:1221-1233. [PMID: 32749905 DOI: 10.1080/14787210.2020.1794815] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
INTRODUCTION Numerous bacterial behaviors are regulated by a cell-density dependent mechanism known as Quorum Sensing (QS). QS relies on communication between bacterial cells using diffusible signaling molecules known as autoinducers. QS regulates physiological processes such as metabolism, virulence, and biofilm formation. Quorum Quenching (QQ) is the inhibition of QS using chemical or enzymatic means to counteract behaviors regulated by QS. AREAS COVERED We examine the main, diverse QS mechanisms present in bacterial species, with a special emphasis on AHL-mediated QS. We also discuss key in vitro and in vivo systems in which interference in QS was investigated. Additionally, we highlight promising developments, such as the substrate preference of the used enzymatic quencher, in the application of interference in QS to counter bacterial virulence. EXPERT OPINION Enabled via the recent isolation of highly stable quorum quenching enzymes and/or molecular engineering efforts, the effects of the interference in QS were recently evaluated outside of the traditional model of single species culture. Signal disruption in complex microbial communities was shown to result in the disruption of complex microbial behaviors, and changes in population structures. These new findings, and future studies, may result in significant changes in the traditional views about QS.
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Affiliation(s)
- Rakesh Sikdar
- Biochemistry, Molecular Biology & Biophysics Department and BioTechnology Institute, University of Minnesota , Saint Paul, Minnesota, USA
| | - Mikael Elias
- Biochemistry, Molecular Biology & Biophysics Department and BioTechnology Institute, University of Minnesota , Saint Paul, Minnesota, USA
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Chatterjee P, Sass G, Swietnicki W, Stevens DA. Review of Potential Pseudomonas Weaponry, Relevant to the Pseudomonas-Aspergillus Interplay, for the Mycology Community. J Fungi (Basel) 2020; 6:jof6020081. [PMID: 32517271 PMCID: PMC7345761 DOI: 10.3390/jof6020081] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 06/03/2020] [Accepted: 06/03/2020] [Indexed: 12/15/2022] Open
Abstract
Pseudomonas aeruginosa is one of the most prominent opportunistic bacteria in airways of cystic fibrosis patients and in immunocompromised patients. These bacteria share the same polymicrobial niche with other microbes, such as the opportunistic fungus Aspergillus fumigatus. Their inter-kingdom interactions and diverse exchange of secreted metabolites are responsible for how they both fare in competition for ecological niches. The outcomes of their contests likely determine persistent damage and degeneration of lung function. With a myriad of virulence factors and metabolites of promising antifungal activity, P. aeruginosa products or their derivatives may prove useful in prophylaxis and therapy against A. fumigatus. Quorum sensing underlies the primary virulence strategy of P. aeruginosa, which serves as cell–cell communication and ultimately leads to the production of multiple virulence factors. Understanding the quorum-sensing-related pathogenic mechanisms of P. aeruginosa is a first step for understanding intermicrobial competition. In this review, we provide a basic overview of some of the central virulence factors of P. aeruginosa that are regulated by quorum-sensing response pathways and briefly discuss the hitherto known antifungal properties of these virulence factors. This review also addresses the role of the bacterial secretion machinery regarding virulence factor secretion and maintenance of cell–cell communication.
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Affiliation(s)
- Paulami Chatterjee
- California Institute for Medical Research, San Jose, CA 95128, USA; (P.C.); (G.S.)
| | - Gabriele Sass
- California Institute for Medical Research, San Jose, CA 95128, USA; (P.C.); (G.S.)
| | - Wieslaw Swietnicki
- Department of Immunology of Infectious Diseases, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, 50-114 Wroclaw, Poland;
| | - David A. Stevens
- California Institute for Medical Research, San Jose, CA 95128, USA; (P.C.); (G.S.)
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
- Correspondence: ; Tel.: +1-408-998-4554
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