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Kasza K, Soukarieh F, Romero M, Hardie KR, Gurnani P, Cámara M, Alexander C. Triblock copolymer micelles enhance solubility, permeability and activity of a quorum sensing inhibitor against Pseudomonas aeruginosa biofilms. RSC APPLIED POLYMERS 2024; 2:444-455. [PMID: 38800514 PMCID: PMC11114570 DOI: 10.1039/d3lp00208j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 02/26/2024] [Indexed: 05/29/2024]
Abstract
Antimicrobial resistance is a threat to public health for which new treatments are urgently required. The capability of bacteria to form biofilms is of particular concern as it enables high bacterial tolerance to conventional therapies by reducing drug diffusion through the dense, exopolymeric biofilm matrix and the upregulation of antimicrobial resistance machinery. Quorum sensing (QS), a process where bacteria use diffusible chemical signals to coordinate group behaviour, has been shown to be closely interconnected with biofilm formation and bacterial virulence in many top priority pathogens including Pseudomonas aeruginosa. Inhibition of QS pathways therefore pose an attractive target for new therapeutics. We have recently reported a new series of pqs quorum sensing inhibitors (QSIs) that serve as potentiators for antibiotics in P. aeruginosa infections. The impact on biofilms of some reported QSIs was however hindered by their poor penetration through the bacterial biofilm, limiting the potential for clinical translation. In this study we developed a series of poly(β-amino ester) (PBAE) triblock copolymers and evaluated their ability to form micelles, encapsulate a QSI and enhance subsequent delivery to P. aeruginosa biofilms. We observed that the QSI could be released from polymer micelles, perturbing the pqs pathway in planktonic P. aeruginosa. In addition, one of the prepared polymer variants increased the QSIs efficacy, leading to an enhanced potentiation of ciprofloxacin (CIP) action and therefore improved reduction in biofilm viability, compared to the non-encapsulated QSI. Thus, we demonstrate QSI encapsulation in polymeric particles can enhance its efficacy through improved biofilm penetration.
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Affiliation(s)
- Karolina Kasza
- Division of Molecular Therapeutics and Formulation, School of Pharmacy, University of Nottingham NG7 2RD UK
- National Biofilms Innovation Centre, School of Life Sciences, Biodiscovery Institute, University Park, University of Nottingham Nottingham NG7 2RD UK
| | - Fadi Soukarieh
- National Biofilms Innovation Centre, School of Life Sciences, Biodiscovery Institute, University Park, University of Nottingham Nottingham NG7 2RD UK
| | - Manuel Romero
- National Biofilms Innovation Centre, School of Life Sciences, Biodiscovery Institute, University Park, University of Nottingham Nottingham NG7 2RD UK
- Department of Microbiology and Parasitology, Faculty of Biology-CIBUS, Universidade de Santiago de Compostela Santiago de Compostela 15782 Spain
- Aquatic One Health Research Center (ARCUS), Universidade de Santiago de Compostela Santiago de Compostela, 15782 Spain
| | - Kim R Hardie
- National Biofilms Innovation Centre, School of Life Sciences, Biodiscovery Institute, University Park, University of Nottingham Nottingham NG7 2RD UK
| | - Pratik Gurnani
- UCL School of Pharmacy, University College London 29-39 Brunswick Square London WC1N 1AX UK
| | - Miguel Cámara
- National Biofilms Innovation Centre, School of Life Sciences, Biodiscovery Institute, University Park, University of Nottingham Nottingham NG7 2RD UK
| | - Cameron Alexander
- Division of Molecular Therapeutics and Formulation, School of Pharmacy, University of Nottingham NG7 2RD UK
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2
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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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3
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Trottier MC, de Oliveira Pereira T, Groleau MC, Hoffman LR, Dandekar AA, Déziel E. The end of the reign of a "master regulator''? A defect in function of the LasR quorum sensing regulator is a common feature of Pseudomonas aeruginosa isolates. mBio 2024; 15:e0237623. [PMID: 38315035 PMCID: PMC10936206 DOI: 10.1128/mbio.02376-23] [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] [Indexed: 02/07/2024] Open
Abstract
Pseudomonas aeruginosa, a bacterium causing infections in immunocompromised individuals, regulates several of its virulence functions using three interlinked quorum sensing (QS) systems (las, rhl, and pqs). Despite its presumed importance in regulating virulence, dysfunction of the las system regulator LasR occurs frequently in strains isolated from various environments, including clinical infections. This newfound abundance of LasR-defective strains calls into question existing hypotheses regarding their selection. Indeed, current assumptions concerning factors driving the emergence of LasR-deficient isolates and the role of LasR in the QS hierarchy must be reconsidered. Here, we propose that LasR is not the primary master regulator of QS in all P. aeruginosa genetic backgrounds, even though it remains ecologically significant. We also revisit and complement current knowledge on the ecology of LasR-dependent QS in P. aeruginosa, discuss the hypotheses explaining the putative adaptive benefits of selecting against LasR function, and consider the implications of this renewed understanding.
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Affiliation(s)
- Mylène C. Trottier
- Centre Armand-Frappier Santé Biotechnologie, Institut National de la Recherche Scientifique (INRS), Laval, Québec, Canada
| | - Thays de Oliveira Pereira
- Centre Armand-Frappier Santé Biotechnologie, Institut National de la Recherche Scientifique (INRS), Laval, Québec, Canada
| | - Marie-Christine Groleau
- Centre Armand-Frappier Santé Biotechnologie, Institut National de la Recherche Scientifique (INRS), Laval, Québec, Canada
| | - Lucas R. Hoffman
- Departments of Pediatrics and Microbiology, University of Washington, Seattle, Washington, USA
| | - Ajai A. Dandekar
- Departments of Medicine and Microbiology, University of Washington, Seattle, Washington, USA
| | - Eric Déziel
- Centre Armand-Frappier Santé Biotechnologie, Institut National de la Recherche Scientifique (INRS), Laval, Québec, Canada
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4
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Deery J, Carmody M, Flavin R, Tomanek M, O'Keeffe M, McGlacken GP, Reen FJ. Comparative genomics reveals distinct diversification patterns among LysR-type transcriptional regulators in the ESKAPE pathogen Pseudomonas aeruginosa. Microb Genom 2024; 10:001205. [PMID: 38421269 PMCID: PMC10926688 DOI: 10.1099/mgen.0.001205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Accepted: 02/06/2024] [Indexed: 03/02/2024] Open
Abstract
Pseudomonas aeruginosa, a harmful nosocomial pathogen associated with cystic fibrosis and burn wounds, encodes for a large number of LysR-type transcriptional regulator proteins. To understand how and why LTTR proteins evolved with such frequency and to establish whether any relationships exist within the distribution we set out to identify the patterns underpinning LTTR distribution in P. aeruginosa and to uncover cluster-based relationships within the pangenome. Comparative genomic studies revealed that in the JGI IMG database alone ~86 000 LTTRs are present across the sequenced genomes (n=699). They are widely distributed across the species, with core LTTRs present in >93 % of the genomes and accessory LTTRs present in <7 %. Analysis showed that subsets of core LTTRs can be classified as either variable (typically specific to P. aeruginosa) or conserved (and found to be distributed in other Pseudomonas species). Extending the analysis to the more extensive Pseudomonas database, PA14 rooted analysis confirmed the diversification patterns and revealed PqsR, the receptor for the Pseudomonas quinolone signal (PQS) and 2-heptyl-4-quinolone (HHQ) quorum-sensing signals, to be amongst the most variable in the dataset. Successful complementation of the PAO1 pqsR - mutant using representative variant pqsR sequences suggests a degree of structural promiscuity within the most variable of LTTRs, several of which play a prominent role in signalling and communication. These findings provide a new insight into the diversification of LTTR proteins within the P. aeruginosa species and suggests a functional significance to the cluster, conservation and distribution patterns identified.
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Affiliation(s)
- Jamie Deery
- School of Microbiology, University College Cork, Cork, Ireland
| | - Muireann Carmody
- School of Microbiology, University College Cork, Cork, Ireland
- School of Chemistry, University College Cork, Cork, Ireland
| | - Rhiannon Flavin
- School of Microbiology, University College Cork, Cork, Ireland
| | - Malwina Tomanek
- School of Microbiology, University College Cork, Cork, Ireland
| | - Maria O'Keeffe
- School of Microbiology, University College Cork, Cork, Ireland
| | - Gerard P. McGlacken
- School of Chemistry, University College Cork, Cork, Ireland
- Synthesis and Solid State Pharmaceutical Centre, University College Cork, Cork, Ireland
| | - F. Jerry Reen
- School of Microbiology, University College Cork, Cork, Ireland
- Synthesis and Solid State Pharmaceutical Centre, University College Cork, Cork, Ireland
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5
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Muriel-Millán LF, Montelongo-Martínez LF, González-Valdez A, Bedoya-Pérez LP, Cocotl-Yañez M, Soberón-Chávez G. The alternative sigma factor RpoS regulates Pseudomonas aeruginosa quorum sensing response by repressing the pqsABCDE operon and activating vfr. Mol Microbiol 2024; 121:291-303. [PMID: 38169053 DOI: 10.1111/mmi.15224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 12/02/2023] [Accepted: 12/22/2023] [Indexed: 01/05/2024]
Abstract
Pseudomonas aeruginosa is an important opportunistic pathogen. Several of its virulence-related processes, including the synthesis of pyocyanin (PYO) and biofilm formation, are controlled by quorum sensing (QS). It has been shown that the alternative sigma factor RpoS regulates QS through the reduction of lasR and rhlR transcription (encoding QS regulators). However, paradoxically, the absence of RpoS increases PYO production and biofilm development (that are RhlR dependent) by unknown mechanisms. Here, we show that RpoS represses pqsE transcription, which impacts the stability and activity of RhlR. In the absence of RpoS, rhlR transcript levels are reduced but not the RhlR protein concentration, presumably by its stabilization by PqsE, whose expression is increased. We also report that PYO synthesis and the expression of pqsE and phzA1B1C1D1E1F1G1 operon exhibit the same pattern at different RpoS concentrations, suggesting that the RpoS-dependent PYO production is due to its ability to modify PqsE concentration, which in turn modulates the activation of the phzA1 promoter by RhlR. Finally, we demonstrate that RpoS favors the expression of Vfr, which activates the transcription of lasR and rhlR. Our study contributes to the understanding of how RpoS modulates the QS response in P. aeruginosa, exerting both negative and positive regulation.
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Affiliation(s)
- Luis Felipe Muriel-Millán
- Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, Ciudad de México, Mexico
| | - Luis Fernando Montelongo-Martínez
- Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, Ciudad de México, Mexico
| | - Abigail González-Valdez
- Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, Ciudad de México, Mexico
| | - Leidy Patricia Bedoya-Pérez
- Programa de Biología Sintética, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico
| | - Miguel Cocotl-Yañez
- Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad Universitaria, Ciudad de México, Mexico
| | - Gloria Soberón-Chávez
- Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, Ciudad de México, Mexico
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Vinayavekhin N, Wattanophas T, Murphy MF, Vangnai AS, Hobbs G. Metabolomics responses and tolerance of Pseudomonas aeruginosa under acoustic vibration stress. PLoS One 2024; 19:e0297030. [PMID: 38285708 PMCID: PMC10824448 DOI: 10.1371/journal.pone.0297030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Accepted: 12/25/2023] [Indexed: 01/31/2024] Open
Abstract
Sound has been shown to impact microbial behaviors. However, our understanding of the chemical and molecular mechanisms underlying these microbial responses to acoustic vibration is limited. In this study, we used untargeted metabolomics analysis to investigate the effects of 100-Hz acoustic vibration on the intra- and extracellular hydrophobic metabolites of P. aeruginosa PAO1. Our findings revealed increased levels of fatty acids and their derivatives, quinolones, and N-acylethanolamines upon sound exposure, while rhamnolipids (RLs) showed decreased levels. Further quantitative real-time polymerase chain reaction experiments showed slight downregulation of the rhlA gene (1.3-fold) and upregulation of fabY (1.5-fold), fadE (1.7-fold), and pqsA (1.4-fold) genes, which are associated with RL, fatty acid, and quinolone biosynthesis. However, no alterations in the genes related to the rpoS regulators or quorum-sensing networks were observed. Supplementing sodium oleate to P. aeruginosa cultures to simulate the effects of sound resulted in increased tolerance of P. aeruginosa in the presence of sound at 48 h, suggesting a potential novel response-tolerance correlation. In contrast, adding RL, which went against the response direction, did not affect its growth. Overall, these findings provide potential implications for the control and manipulation of virulence and bacterial characteristics for medical and industrial applications.
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Affiliation(s)
- Nawaporn Vinayavekhin
- Center of Excellence in Natural Products Chemistry, Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
- Center of Excellence in Biocatalyst and Sustainable Biotechnology, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
| | - Thanyaporn Wattanophas
- Center of Excellence in Natural Products Chemistry, Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
| | - Mark Francis Murphy
- School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Liverpool, United Kingdom
| | - Alisa S. Vangnai
- Center of Excellence in Biocatalyst and Sustainable Biotechnology, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
- Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
| | - Glyn Hobbs
- School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Liverpool, United Kingdom
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7
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Vadakkan K, Ngangbam AK, Sathishkumar K, Rumjit NP, Cheruvathur MK. A review of chemical signaling pathways in the quorum sensing circuit of Pseudomonas aeruginosa. Int J Biol Macromol 2024; 254:127861. [PMID: 37939761 DOI: 10.1016/j.ijbiomac.2023.127861] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 10/26/2023] [Accepted: 11/01/2023] [Indexed: 11/10/2023]
Abstract
Pseudomonas aeruginosa, an increasingly common competitive and biofilm organism in healthcare infection with sophisticated, interlinked and hierarchic quorum systems (Las, Rhl, PQS, and IQS), creates the greatest threats to the medical industry and has rendered prevailing chemotherapy medications ineffective. The rise of multidrug resistance has evolved into a concerning and potentially fatal occurrence for human life. P. aeruginosa biofilm development is assisted by exopolysaccharides, extracellular DNA, proteins, macromolecules, cellular signaling and interaction. Quorum sensing is a communication process between cells that involves autonomous inducers and regulators. Quorum-induced infectious agent biofilms and the synthesis of virulence factors have increased disease transmission, medication resistance, infection episodes, hospitalizations and mortality. Hence, quorum sensing may be a potential therapeutical target for bacterial illness, and developing quorum inhibitors as an anti-virulent tool could be a promising treatment strategy for existing antibiotics. Quorum quenching is a prevalent technique for treating infections caused by microbes because it diminishes microbial pathogenesis and increases microbe biofilm sensitivity to antibiotics, making it a potential candidate for drug development. This paper examines P. aeruginosa quorum sensing, the hierarchy of quorum sensing mechanism, quorum sensing inhibition and quorum sensing inhibitory agents as a drug development strategy to supplement traditional antibiotic strategies.
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Affiliation(s)
- Kayeen Vadakkan
- Department of Biology, St. Mary's College, Thrissur, Kerala 680020, India; Manipur International University, Imphal, Manipur 795140, India.
| | | | - Kuppusamy Sathishkumar
- Rhizosphere Biology Laboratory, Department of Microbiology, Bharathidasan University, Tiruchirappalli, Tamil Nadu 620024, India; Department of Computational Biology, Institute of Bioinformatics, Saveetha School of Engineering, Saveetha Institute of Medical and Technical Sciences, Thandalam, Chennai 602 105, Tamil Nadu, India
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8
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Ghosh M, Raghav S, Ghosh P, Maity S, Mohela K, Jain D. Structural analysis of novel drug targets for mitigation of Pseudomonas aeruginosa biofilms. FEMS Microbiol Rev 2023; 47:fuad054. [PMID: 37771093 DOI: 10.1093/femsre/fuad054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 09/20/2023] [Accepted: 09/27/2023] [Indexed: 09/30/2023] Open
Abstract
Pseudomonas aeruginosa is an opportunistic human pathogen responsible for acute and chronic, hard to treat infections. Persistence of P. aeruginosa is due to its ability to develop into biofilms, which are sessile bacterial communities adhered to substratum and encapsulated in layers of self-produced exopolysaccharides. These biofilms provide enhanced protection from the host immune system and resilience towards antibiotics, which poses a challenge for treatment. Various strategies have been expended for combating biofilms, which involve inhibiting biofilm formation or promoting their dispersal. The current remediation approaches offer some hope for clinical usage, however, treatment and eradication of preformed biofilms is still a challenge. Thus, identifying novel targets and understanding the detailed mechanism of biofilm regulation becomes imperative. Structure-based drug discovery (SBDD) provides a powerful tool that exploits the knowledge of atomic resolution details of the targets to search for high affinity ligands. This review describes the available structural information on the putative target protein structures that can be utilized for high throughput in silico drug discovery against P. aeruginosa biofilms. Integrating available structural information on the target proteins in readily accessible format will accelerate the process of drug discovery.
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Affiliation(s)
- Moumita Ghosh
- Transcription Regulation Lab, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurugram Expressway, Faridabad, Haryana-121001, India
| | - Shikha Raghav
- Transcription Regulation Lab, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurugram Expressway, Faridabad, Haryana-121001, India
| | - Puja Ghosh
- Transcription Regulation Lab, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurugram Expressway, Faridabad, Haryana-121001, India
| | - Swagatam Maity
- Transcription Regulation Lab, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurugram Expressway, Faridabad, Haryana-121001, India
| | - Kavery Mohela
- Transcription Regulation Lab, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurugram Expressway, Faridabad, Haryana-121001, India
| | - Deepti Jain
- Transcription Regulation Lab, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurugram Expressway, Faridabad, Haryana-121001, India
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9
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Bru JL, Kasallis SJ, Zhuo Q, Høyland-Kroghsbo NM, Siryaporn A. Swarming of P. aeruginosa: Through the lens of biophysics. BIOPHYSICS REVIEWS 2023; 4:031305. [PMID: 37781002 PMCID: PMC10540860 DOI: 10.1063/5.0128140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 08/29/2023] [Indexed: 10/03/2023]
Abstract
Swarming is a collective flagella-dependent movement of bacteria across a surface that is observed across many species of bacteria. Due to the prevalence and diversity of this motility modality, multiple models of swarming have been proposed, but a consensus on a general mechanism for swarming is still lacking. Here, we focus on swarming by Pseudomonas aeruginosa due to the abundance of experimental data and multiple models for this species, including interpretations that are rooted in biology and biophysics. In this review, we address three outstanding questions about P. aeruginosa swarming: what drives the outward expansion of a swarm, what causes the formation of dendritic patterns (tendrils), and what are the roles of flagella? We review models that propose biologically active mechanisms including surfactant sensing as well as fluid mechanics-based models that consider swarms as thin liquid films. Finally, we reconcile recent observations of P. aeruginosa swarms with early definitions of swarming. This analysis suggests that mechanisms associated with sliding motility have a critical role in P. aeruginosa swarm formation.
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Affiliation(s)
- Jean-Louis Bru
- Department of Molecular Biology and Biochemistry, University of California Irvine, Irvine, California 92697, USA
| | - Summer J. Kasallis
- Department of Physics and Astronomy, University of California Irvine, Irvine, California 92697, USA
| | - Quantum Zhuo
- Department of Physics and Astronomy, University of California Irvine, Irvine, California 92697, USA
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10
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Scheller D, Becker F, Wimbert A, Meggers D, Pienkoß S, Twittenhoff C, Knoke LR, Leichert LI, Narberhaus F. The oxidative stress response, in particular the katY gene, is temperature-regulated in Yersinia pseudotuberculosis. PLoS Genet 2023; 19:e1010669. [PMID: 37428814 PMCID: PMC10358904 DOI: 10.1371/journal.pgen.1010669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 06/12/2023] [Indexed: 07/12/2023] Open
Abstract
Pathogenic bacteria, such as Yersinia pseudotuberculosis encounter reactive oxygen species (ROS) as one of the first lines of defense in the mammalian host. In return, the bacteria react by mounting an oxidative stress response. Previous global RNA structure probing studies provided evidence for temperature-modulated RNA structures in the 5'-untranslated region (5'-UTR) of various oxidative stress response transcripts, suggesting that opening of these RNA thermometer (RNAT) structures at host-body temperature relieves translational repression. Here, we systematically analyzed the transcriptional and translational regulation of ROS defense genes by RNA-sequencing, qRT-PCR, translational reporter gene fusions, enzymatic RNA structure probing and toeprinting assays. Transcription of four ROS defense genes was upregulated at 37°C. The trxA gene is transcribed into two mRNA isoforms, of which the most abundant short one contains a functional RNAT. Biochemical assays validated temperature-responsive RNAT-like structures in the 5'-UTRs of sodB, sodC and katA. However, they barely conferred translational repression in Y. pseudotuberculosis at 25°C suggesting partially open structures available to the ribosome in the living cell. Around the translation initiation region of katY we discovered a novel, highly efficient RNAT that was primarily responsible for massive induction of KatY at 37°C. By phenotypic characterization of catalase mutants and through fluorometric real-time measurements of the redox-sensitive roGFP2-Orp1 reporter in these strains, we revealed KatA as the primary H2O2 scavenger. Consistent with the upregulation of katY, we observed an improved protection of Y. pseudotuberculosis at 37°C. Our findings suggest a multilayered regulation of the oxidative stress response in Yersinia and an important role of RNAT-controlled katY expression at host body temperature.
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Affiliation(s)
- Daniel Scheller
- Ruhr University Bochum, Faculty of Biology and Biotechnology, Microbial Biology, Bochum, Germany
| | - Franziska Becker
- Ruhr University Bochum, Faculty of Biology and Biotechnology, Microbial Biology, Bochum, Germany
| | - Andrea Wimbert
- Ruhr University Bochum, Faculty of Biology and Biotechnology, Microbial Biology, Bochum, Germany
| | - Dominik Meggers
- Ruhr University Bochum, Faculty of Biology and Biotechnology, Microbial Biology, Bochum, Germany
| | - Stephan Pienkoß
- Ruhr University Bochum, Faculty of Biology and Biotechnology, Microbial Biology, Bochum, Germany
| | - Christian Twittenhoff
- Ruhr University Bochum, Faculty of Biology and Biotechnology, Microbial Biology, Bochum, Germany
| | - Lisa R Knoke
- Ruhr University Bochum, Faculty of Medicine, Institute of Biochemistry and Pathobiochemistry, Microbial Biochemistry, Bochum, Germany
| | - Lars I Leichert
- Ruhr University Bochum, Faculty of Medicine, Institute of Biochemistry and Pathobiochemistry, Microbial Biochemistry, Bochum, Germany
| | - Franz Narberhaus
- Ruhr University Bochum, Faculty of Biology and Biotechnology, Microbial Biology, Bochum, Germany
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11
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The two faces of pyocyanin - why and how to steer its production? World J Microbiol Biotechnol 2023; 39:103. [PMID: 36864230 PMCID: PMC9981528 DOI: 10.1007/s11274-023-03548-w] [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: 12/30/2022] [Accepted: 02/13/2023] [Indexed: 03/04/2023]
Abstract
The ambiguous nature of pyocyanin was noted quite early after its discovery. This substance is a recognized Pseudomonas aeruginosa virulence factor that causes problems in cystic fibrosis, wound healing, and microbiologically induced corrosion. However, it can also be a potent chemical with potential use in a wide variety of technologies and applications, e.g. green energy production in microbial fuel cells, biocontrol in agriculture, therapy in medicine, or environmental protection. In this mini-review, we shortly describe the properties of pyocyanin, its role in the physiology of Pseudomonas and show the ever-growing interest in it. We also summarize the possible ways of modulating pyocyanin production. We underline different approaches of the researchers that aim either at lowering or increasing pyocyanin production by using different culturing methods, chemical additives, physical factors (e.g. electromagnetic field), or genetic engineering techniques. The review aims to present the ambiguous character of pyocyanin, underline its potential, and signalize the possible further research directions.
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12
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Pan X, Liang H, Zhao X, Zhang Q, Chen L, Yue Z, Yin L, Jin Y, Bai F, Cheng Z, Bartlam M, Wu W. Regulatory and structural mechanisms of PvrA-mediated regulation of the PQS quorum-sensing system and PHA biosynthesis in Pseudomonas aeruginosa. Nucleic Acids Res 2023; 51:2691-2708. [PMID: 36744476 PMCID: PMC10085694 DOI: 10.1093/nar/gkad059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 01/17/2023] [Accepted: 01/20/2023] [Indexed: 02/07/2023] Open
Abstract
Pseudomonas aeruginosa is capable of causing acute and chronic infections in various host tissues, which depends on its abilities to effectively utilize host-derived nutrients and produce protein virulence factors and toxic compounds. However, the regulatory mechanisms that direct metabolic intermediates towards production of toxic compounds are poorly understood. We previously identified a regulatory protein PvrA that controls genes involved in fatty acid catabolism by binding to palmitoyl-coenzyme A (CoA). In this study, transcriptomic analyses revealed that PvrA activates the Pseudomonas quinolone signal (PQS) synthesis genes, while suppressing genes for production of polyhydroxyalkanoates (PHAs). When palmitic acid was the sole carbon source, mutation of pvrA reduced production of pyocyanin and rhamnolipids due to defective PQS synthesis, but increased PHA production. We further solved the co-crystal structure of PvrA with palmitoyl-CoA and identified palmitoyl-CoA-binding residues. By using pvrA mutants, we verified the roles of the key palmitoyl-CoA-binding residues in gene regulation in response to palmitic acid. Since the PQS signal molecules, rhamnolipids and PHA synthesis pathways are interconnected by common metabolic intermediates, our results revealed a regulatory mechanism that directs carbon flux from carbon/energy storage to virulence factor production, which might be crucial for the pathogenesis.
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Affiliation(s)
- Xiaolei Pan
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Han Liang
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China.,Tianjin Key Laboratory of Protein Science, Nankai University, Tianjin 300071, China
| | - Xinrui Zhao
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Qionglin Zhang
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China.,Tianjin Key Laboratory of Protein Science, Nankai University, Tianjin 300071, China
| | - Lei Chen
- Department of Plant Biology and Ecology, College of Life Science Nankai University, Tianjin 300071 China
| | - Zhuo Yue
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Liwen Yin
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Yongxin Jin
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Fang Bai
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Zhihui Cheng
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Mark Bartlam
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China.,Tianjin Key Laboratory of Protein Science, Nankai University, Tianjin 300071, China.,Nankai International Advanced Research Institute (Shenzhen Futian), Shenzhen, Guangdong 518045, China
| | - Weihui Wu
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
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13
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Jia J, Parmar D, Ellis JF, Cao T, Cutri AR, Shrout JD, Sweedler JV, Bohn PW. Effect of Micro-Patterned Mucin on Quinolone and Rhamnolipid Profiles of Mucoid Pseudomonas aeruginosa under Antibiotic Stress. ACS Infect Dis 2023; 9:150-161. [PMID: 36538577 PMCID: PMC10116410 DOI: 10.1021/acsinfecdis.2c00519] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Pseudomonas aeruginosa (P. aeruginosa) is commonly implicated in hospital-acquired infections where its capacity to form biofilms on a variety of surfaces and the resulting enhanced antibiotic resistance seriously limit treatment choices. Because surface attachment sensitizes P. aeruginosa to quorum sensing (QS) and induces virulence through both chemical and mechanical cues, we investigate the effect of surface properties through spatially patterned mucin, combined with sub-inhibitory concentrations of tobramycin on QS and virulence factors in both mucoid and non-mucoid P. aeruginosa strains using multi-modal chemical imaging combining confocal Raman microscopy and matrix-assisted laser desorption/ionization-mass spectrometry. Samples comprise surface-adherent static biofilms at a solid-water interface, supernatant liquid, and pellicle biofilms at an air-water interface at various time points. Although the presence of a sub-inhibitory concentration of tobramycin in the supernatant retards growth and development of static biofilms independent of strain and surface mucin patterning, we observe clear differences in the behavior of mucoid and non-mucoid strains. Quinolone signals in a non-mucoid strain are induced earlier and are influenced by mucin surface patterning to a degree not exhibited in the mucoid strain. Additionally, phenazine virulence factors, such as pyocyanin, are observed in the pellicle biofilms of both mucoid and non-mucoid strains but are not detected in the static biofilms from either strain, highlighting the differences in stress response between pellicle and static biofilms. Differences between mucoid and non-mucoid strains are consistent with their strain-specific phenology, in which the mucoid strain develops highly protected biofilms.
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Affiliation(s)
- Jin Jia
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Dharmeshkumar Parmar
- Department of Chemistry and Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Joanna F Ellis
- Department of Chemistry and Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Tianyuan Cao
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Allison R Cutri
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Joshua D Shrout
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana 46556, United States.,Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Jonathan V Sweedler
- Department of Chemistry and Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Paul W Bohn
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States.,Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana 46556, United States
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14
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Evaluating Bacterial Pathogenesis Using a Model of Human Airway Organoids Infected with Pseudomonas aeruginosa Biofilms. Microbiol Spectr 2022; 10:e0240822. [PMID: 36301094 PMCID: PMC9769610 DOI: 10.1128/spectrum.02408-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Pseudomonas aeruginosa is one of the leading invasive agents of human pulmonary infection, especially in patients with compromised immunity. Prior studies have used various in vitro models to establish P. aeruginosa infection and to analyze transcriptomic profiles of either the host or pathogen, and yet how much those works are relevant to the genuine human airway still raises doubts. In this study, we cultured and differentiated human airway organoids (HAOs) that recapitulate, to a large extent, the histological and physiological features of the native human mucociliary epithelium. HAOs were then employed as a host model to monitor P. aeruginosa biofilm development. Through dual-species transcriptome sequencing (RNA-seq) analyses, we found that quorum sensing (QS) and several associated protein secretion systems were significantly upregulated in HAO-associated bacteria. Cocultures of HAOs and QS-defective mutants further validated the role of QS in the maintenance of a robust biofilm and disruption of host tissue. Simultaneously, the expression magnitude of multiple inflammation-associated signaling pathways was higher in the QS mutant-infected HAOs, suggesting that QS promotes immune evasion at the transcriptional level. Altogether, modeling infection of HAOs by P. aeruginosa captured several crucial facets in host responses and bacterial pathogenesis, with QS being the most dominant virulence pathway showing profound effects on both bacterial biofilm and host immune responses. Our results revealed that HAOs are an optimal model for studying the interaction between the airway epithelium and bacterial pathogens. IMPORTANCE Human airway organoids (HAOs) are an organotypic model of human airway mucociliary epithelium. The HAOs can closely resemble their origin organ in terms of epithelium architecture and physiological function. Accumulating studies have revealed the great values of the HAO cultures in host-pathogen interaction research. In this study, HAOs were used as a host model to grow Pseudomonas aeruginosa biofilm, which is one of the most common pathogens found in pulmonary infection cases. Dual transcriptome sequencing (RNA-seq) analyses showed that the cocultures have changed the gene expression pattern of both sides significantly and simultaneously. Bacterial quorum sensing (QS), the most upregulated pathway, contributed greatly to biofilm formation, disruption of barrier function, and subversion of host immune responses. Our study therefore provides a global insight into the transcriptomic responses of both P. aeruginosa and human airway epithelium.
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15
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Feathers JR, Richael EK, Simanek KA, Fromme JC, Paczkowski JE. Structure of the RhlR-PqsE complex from Pseudomonas aeruginosa reveals mechanistic insights into quorum-sensing gene regulation. Structure 2022; 30:1626-1636.e4. [PMID: 36379213 PMCID: PMC9722607 DOI: 10.1016/j.str.2022.10.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 08/26/2022] [Accepted: 10/20/2022] [Indexed: 11/16/2022]
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that is responsible for thousands of deaths every year in the United States. P. aeruginosa virulence factor production is mediated by quorum sensing, a mechanism of bacterial cell-cell communication that relies on the production and detection of signal molecules called autoinducers. In P. aeruginosa, the transcription factor receptor RhlR is activated by a RhlI-synthesized autoinducer. We recently showed that RhlR-dependent transcription is enhanced by a physical interaction with the enzyme PqsE via increased affinity of RhlR for promoter DNA. However, the molecular basis for complex formation and how complex formation enhanced RhlR transcriptional activity remained unclear. Here, we report the structure of ligand-bound RhlR in complex with PqsE. Additionally, we determined the structure of the complex bound with DNA, revealing the mechanism by which RhlR-mediated transcription is enhanced by PqsE, thereby establishing the molecular basis for RhlR-dependent virulence factor production in P. aeruginosa.
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Affiliation(s)
- J Ryan Feathers
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA
| | - Erica K Richael
- Division of Genetics, Wadsworth Center, New York State Department of Health, Albany, NY 12208, USA
| | - Kayla A Simanek
- Department of Biomedical Sciences, University at Albany, School of Public Health, Albany, NY 12201, USA
| | - J Christopher Fromme
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA
| | - Jon E Paczkowski
- Division of Genetics, Wadsworth Center, New York State Department of Health, Albany, NY 12208, USA; Department of Biomedical Sciences, University at Albany, School of Public Health, Albany, NY 12201, USA.
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16
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Borgert SR, Henke S, Witzgall F, Schmelz S, Zur Lage S, Hotop SK, Stephen S, Lübken D, Krüger J, Gomez NO, van Ham M, Jänsch L, Kalesse M, Pich A, Brönstrup M, Häussler S, Blankenfeldt W. Moonlighting chaperone activity of the enzyme PqsE contributes to RhlR-controlled virulence of Pseudomonas aeruginosa. Nat Commun 2022; 13:7402. [PMID: 36456567 PMCID: PMC9715718 DOI: 10.1038/s41467-022-35030-w] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 11/14/2022] [Indexed: 12/05/2022] Open
Abstract
Pseudomonas aeruginosa is a major cause of nosocomial infections and also leads to severe exacerbations in cystic fibrosis or chronic obstructive pulmonary disease. Three intertwined quorum sensing systems control virulence of P. aeruginosa, with the rhl circuit playing the leading role in late and chronic infections. The majority of traits controlled by rhl transcription factor RhlR depend on PqsE, a dispensable thioesterase in Pseudomonas Quinolone Signal (PQS) biosynthesis that interferes with RhlR through an enigmatic mechanism likely involving direct interaction of both proteins. Here we show that PqsE and RhlR form a 2:2 protein complex that, together with RhlR agonist N-butanoyl-L-homoserine lactone (C4-HSL), solubilizes RhlR and thereby renders the otherwise insoluble transcription factor active. We determine crystal structures of the complex and identify residues essential for the interaction. To corroborate the chaperone-like activity of PqsE, we design stability-optimized variants of RhlR that bypass the need for C4-HSL and PqsE in activating PqsE/RhlR-controlled processes of P. aeruginosa. Together, our data provide insight into the unique regulatory role of PqsE and lay groundwork for developing new P. aeruginosa-specific pharmaceuticals.
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Affiliation(s)
- Sebastian Roman Borgert
- Department Structure and Function of Proteins, Helmholtz Centre for Infection Research, Inhoffenstr. 7, 38124, Braunschweig, Germany
| | - Steffi Henke
- Department Structure and Function of Proteins, Helmholtz Centre for Infection Research, Inhoffenstr. 7, 38124, Braunschweig, Germany
| | - Florian Witzgall
- Department Structure and Function of Proteins, Helmholtz Centre for Infection Research, Inhoffenstr. 7, 38124, Braunschweig, Germany
| | - Stefan Schmelz
- Department Structure and Function of Proteins, Helmholtz Centre for Infection Research, Inhoffenstr. 7, 38124, Braunschweig, Germany
| | - Susanne Zur Lage
- Department Structure and Function of Proteins, Helmholtz Centre for Infection Research, Inhoffenstr. 7, 38124, Braunschweig, Germany
| | - Sven-Kevin Hotop
- Department Chemical Biology, Helmholtz Centre for Infection Research, Inhoffenstr. 7, 38124, Braunschweig, Germany
| | - Steffi Stephen
- Department Chemical Biology, Helmholtz Centre for Infection Research, Inhoffenstr. 7, 38124, Braunschweig, Germany
| | - Dennis Lübken
- Institute of Organic Chemistry, Leibniz University Hannover, Schneiderberg 1B, 30167, Hannover, Germany
| | - Jonas Krüger
- Department Molecular Bacteriology, Helmholtz Centre for Infection Research, Inhoffenstr. 7, 38124, Braunschweig, Germany
| | - Nicolas Oswaldo Gomez
- Department Molecular Bacteriology, Helmholtz Centre for Infection Research, Inhoffenstr. 7, 38124, Braunschweig, Germany
| | - Marco van Ham
- Cellular Proteomics, Helmholtz Centre for Infection Research, Inhoffenstr. 7, 38124, Braunschweig, Germany
| | - Lothar Jänsch
- Cellular Proteomics, Helmholtz Centre for Infection Research, Inhoffenstr. 7, 38124, Braunschweig, Germany
| | - Markus Kalesse
- Institute of Organic Chemistry, Leibniz University Hannover, Schneiderberg 1B, 30167, Hannover, Germany
| | - Andreas Pich
- Institute for Toxicology, Core Facility Proteomics, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
| | - Mark Brönstrup
- Department Chemical Biology, Helmholtz Centre for Infection Research, Inhoffenstr. 7, 38124, Braunschweig, Germany
| | - Susanne Häussler
- Department Molecular Bacteriology, Helmholtz Centre for Infection Research, Inhoffenstr. 7, 38124, Braunschweig, Germany
| | - Wulf Blankenfeldt
- Department Structure and Function of Proteins, Helmholtz Centre for Infection Research, Inhoffenstr. 7, 38124, Braunschweig, Germany.
- Institute for Biochemistry, Biotechnology and Bioinformatics, Technische Universität Braunschweig, Spielmannstr. 7, 38106, Braunschweig, Germany.
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17
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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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18
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Resistance Is Not Futile: The Role of Quorum Sensing Plasticity in Pseudomonas aeruginosa Infections and Its Link to Intrinsic Mechanisms of Antibiotic Resistance. Microorganisms 2022; 10:microorganisms10061247. [PMID: 35744765 PMCID: PMC9228389 DOI: 10.3390/microorganisms10061247] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 06/06/2022] [Accepted: 06/09/2022] [Indexed: 01/01/2023] Open
Abstract
Bacteria use a cell-cell communication process called quorum sensing (QS) to orchestrate collective behaviors. QS relies on the group-wide detection of extracellular signal molecules called autoinducers (AI). Quorum sensing is required for virulence and biofilm formation in the human pathogen Pseudomonas aeruginosa. In P. aeruginosa, LasR and RhlR are homologous LuxR-type soluble transcription factor receptors that bind their cognate AIs and activate the expression of genes encoding functions required for virulence and biofilm formation. While some bacterial signal transduction pathways follow a linear circuit, as phosphoryl groups are passed from one carrier protein to another ultimately resulting in up- or down-regulation of target genes, the QS system in P. aeruginosa is a dense network of receptors and regulators with interconnecting regulatory systems and outputs. Once activated, it is not understood how LasR and RhlR establish their signaling hierarchy, nor is it clear how these pathway connections are regulated, resulting in chronic infection. Here, we reviewed the mechanisms of QS progression as it relates to bacterial pathogenesis and antimicrobial resistance and tolerance.
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19
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Genetic and Transcriptomic Characteristics of RhlR-Dependent Quorum Sensing in Cystic Fibrosis Isolates of Pseudomonas aeruginosa. mSystems 2022; 7:e0011322. [PMID: 35471121 PMCID: PMC9040856 DOI: 10.1128/msystems.00113-22] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
In people with the genetic disease cystic fibrosis (CF), bacterial infections involving the opportunistic pathogen Pseudomonas aeruginosa are a significant cause of morbidity and mortality. P. aeruginosa uses a cell-cell signaling mechanism called quorum sensing (QS) to regulate many virulence functions. One type of QS consists of acyl-homoserine lactone (AHL) signals produced by LuxI-type signal synthases, which bind a cognate LuxR-type transcription factor. In laboratory strains and conditions, P. aeruginosa employs two AHL synthase/receptor pairs arranged in a hierarchy, with the LasI/R system controlling the RhlI/R system and many downstream virulence factors. However, P. aeruginosa isolates with inactivating mutations in lasR are frequently isolated from chronic CF infections. We and others have shown that these isolates frequently use RhlR as the primary QS regulator. RhlR is rarely mutated in CF and environmental settings. We were interested in determining whether there were reproducible genetic characteristics of these isolates and whether there was a central group of genes regulated by RhlR in all isolates. We examined five isolates and found signatures of adaptation common to CF isolates. We did not identify a common genetic mechanism to explain the switch from Las- to Rhl-dominated QS. We describe a core RhlR regulon encompassing 20 genes encoding 7 products. These results suggest a key group of QS-regulated factors important for pathogenesis of chronic infections and position RhlR as a target for anti-QS therapeutics. Our work underscores the need to sample a diversity of isolates to understand QS beyond what has been described in laboratory strains. IMPORTANCE The bacterial pathogen Pseudomonas aeruginosa can cause chronic infections that are resistant to treatment in immunocompromised individuals. Over the course of these infections, the original infecting organism adapts to the host environment. P. aeruginosa uses a cell-cell signaling mechanism termed quorum sensing (QS) to regulate virulence factors and cooperative behaviors. The key QS regulator in laboratory strains, LasR, is frequently mutated in infection-adapted isolates, leaving another transcription factor, RhlR, in control of QS gene regulation. Such isolates provide an opportunity to understand Rhl-QS regulation without the confounding effects of LasR, as well as the scope of QS in the context of within-host evolution. We show that a core group of virulence genes is regulated by RhlR in a variety of infection-adapted LasR-null isolates. Our results reveal commonalities in infection-adapted QS gene regulation and key QS factors that may serve as therapeutic targets in the future.
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20
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The PqsE-RhlR Interaction Regulates RhlR DNA Binding to Control Virulence Factor Production in Pseudomonas aeruginosa. Microbiol Spectr 2022; 10:e0210821. [PMID: 35019777 PMCID: PMC8754118 DOI: 10.1128/spectrum.02108-21] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that causes disease in immunocompromised individuals and individuals with underlying pulmonary disorders. P. aeruginosa virulence is controlled by quorum sensing (QS), a bacterial cell-cell communication mechanism that underpins transitions between individual and group behaviors. In P. aeruginosa, the PqsE enzyme and the QS receptor RhlR directly interact to control the expression of genes involved in virulence. Here, we show that three surface-exposed arginine residues on PqsE comprise the site required for interaction with RhlR. We show that a noninteracting PqsE variant [PqsE(NI)] possesses catalytic activity, but is incapable of promoting virulence phenotypes, indicating that interaction with RhlR, and not catalysis, drives these PqsE-dependent behaviors. Biochemical characterization of the PqsE-RhlR interaction coupled with RNA-seq analyses demonstrates that the PqsE-RhlR complex increases the affinity of RhlR for DNA, enabling enhanced expression of genes encoding key virulence factors. These findings provide the mechanism for PqsE-dependent regulation of RhlR and identify a unique regulatory feature of P. aeruginosa QS and its connection to virulence. IMPORTANCE Bacteria use a cell-cell communication process called quorum sensing (QS) to orchestrate collective behaviors. QS relies on the group-wide detection of molecules called autoinducers (AI). QS is required for virulence in the human pathogen Pseudomonas aeruginosa, which can cause fatal infections in patients with underlying pulmonary disorders. In this study, we determine the molecular basis for the physical interaction between two virulence-driving QS components, PqsE and RhlR. We find that the ability of PqsE to bind RhlR correlates with virulence factor production. Since current antimicrobial therapies exacerbate the growing antibiotic resistance problem because they target bacterial growth, we suggest that the PqsE-RhlR interface discovered here represents a new candidate for targeting with small molecule inhibition. Therapeutics that disrupt the PqsE-RhlR interaction should suppress virulence. Targeting bacterial behaviors such as QS, rather than bacterial growth, represents an attractive alternative for exploration because such therapies could potentially minimize the development of resistance.
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21
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Duplantier M, Lohou E, Sonnet P. Quorum Sensing Inhibitors to Quench P. aeruginosa Pathogenicity. Pharmaceuticals (Basel) 2021; 14:1262. [PMID: 34959667 PMCID: PMC8707152 DOI: 10.3390/ph14121262] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 12/01/2021] [Accepted: 12/02/2021] [Indexed: 12/22/2022] Open
Abstract
The emergence and the dissemination of multidrug-resistant bacteria constitute a major public health issue. Among incriminated Gram-negative bacteria, Pseudomonas aeruginosa has been designated by the WHO as a critical priority threat. During the infection process, this pathogen secretes various virulence factors in order to adhere and colonize host tissues. Furthermore, P. aeruginosa has the capacity to establish biofilms that reinforce its virulence and intrinsic drug resistance. The regulation of biofilm and virulence factor production of this micro-organism is controlled by a specific bacterial communication system named Quorum Sensing (QS). The development of anti-virulence agents targeting QS that could attenuate P. aeruginosa pathogenicity without affecting its growth seems to be a promising new therapeutic strategy. This could prevent the selective pressure put on bacteria by the conventional antibiotics that cause their death and promote resistant strain survival. This review describes the QS-controlled pathogenicity of P. aeruginosa and its different specific QS molecular pathways, as well as the recent advances in the development of innovative QS-quenching anti-virulence agents to fight anti-bioresistance.
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Affiliation(s)
| | | | - Pascal Sonnet
- AGIR, UR4294, UFR of Pharmacy, Jules Verne University of Picardie, 80037 Amiens, France; (M.D.); (E.L.)
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22
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García-Reyes S, Cocotl-Yañez M, Soto-Aceves MP, González-Valdez A, Servín-González L, Soberón-Chávez G. PqsR-independent quorum-sensing response of Pseudomonas aeruginosa ATCC 9027 outlier-strain reveals new insights on the PqsE effect on RhlR activity. Mol Microbiol 2021; 116:1113-1123. [PMID: 34418194 DOI: 10.1111/mmi.14797] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 08/16/2021] [Accepted: 08/17/2021] [Indexed: 11/28/2022]
Abstract
Pseudomonas aeruginosa is a ubiquitous environmental bacterium and an opportunistic pathogen that represents an important health hazard. The quorum-sensing response regulates the expression of several virulence factors and involves three regulons: Las, Rhl, and Pqs. The P. aeruginosa ATCC 9027 strain, which belongs to the genetically diverse PA7 clade, contains a frame-shift mutation in the pqsR gene that encodes a transcriptional activator necessary for pyocyanin (PYO) synthesis in type strains PAO1 and PA14. Here we characterize the PqsE-dependent production of PYO in strain ATCC 9027. We show that this strain expresses pqsE independently of PqsR and in the absence of quinolone production, and that PqsE promotes the RhlR-dependent production of PYO, yet this production is not strictly dependent on PqsE. In addition, we show that in both strains ATCC 9027 and PAO1, PqsE overexpression causes an increased concentration of RhlR and enhances PYO production but does not affect rhamnolipids (RL) production in the same way. These results suggest that PqsE interaction with RhlR preferentially modifies its ability to activate transcription of genes involved in PYO production and provide new evidence about PqsE-dependent RhlR activation, highlighting the variability of the QS response among different P. aeruginosa clades and strains. HIGHLIGHTS: Pseudomonas aeruginosa ATCC 9027 is able to produce pyocyanin in phosphate limiting conditions, even in the absence of a functional PqsR. This strain does not produce alkyl quinolones like PQS and HHQ, but expresses pqsE. Synthesis of pyocyanin by ATCC 9027 is only partially dependent on pqsE. The overexpression of pqsE in the ATCC 9027 and PAO1 strains causes pyocyanin overproduction. The overexpression of pqsE in these strains causes an increased RhlR concentration without affecting rhlR transcription or translation. Rhamnolipids production is not affected to the same extent as pyocyanin by overexpression of pqsE in these strains.
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Affiliation(s)
- Selene García-Reyes
- Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, Ciudad de Mexico, Mexico
| | - Miguel Cocotl-Yañez
- Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad Universitaria, Ciudad de Mexico, Mexico
| | - Martín Paolo Soto-Aceves
- Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, Ciudad de Mexico, Mexico
| | - Abigail González-Valdez
- Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, Ciudad de Mexico, Mexico
| | - Luis Servín-González
- Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, Ciudad de Mexico, Mexico
| | - Gloria Soberón-Chávez
- Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, Ciudad de Mexico, Mexico
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Lee C, Klockgether J, Fischer S, Trcek J, Tümmler B, Römling U. Why? - Successful Pseudomonas aeruginosa clones with a focus on clone C. FEMS Microbiol Rev 2021; 44:740-762. [PMID: 32990729 PMCID: PMC7685784 DOI: 10.1093/femsre/fuaa029] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 07/12/2020] [Indexed: 12/20/2022] Open
Abstract
The environmental species Pseudomonas aeruginosa thrives in a variety of habitats. Within the epidemic population structure of P. aeruginosa, occassionally highly successful clones that are equally capable to succeed in the environment and the human host arise. Framed by a highly conserved core genome, individual members of successful clones are characterized by a high variability in their accessory genome. The abundance of successful clones might be funded in specific features of the core genome or, although not mutually exclusive, in the variability of the accessory genome. In clone C, one of the most predominant clones, the plasmid pKLC102 and the PACGI-1 genomic island are two ubiquitous accessory genetic elements. The conserved transmissible locus of protein quality control (TLPQC) at the border of PACGI-1 is a unique horizontally transferred compository element, which codes predominantly for stress-related cargo gene products such as involved in protein homeostasis. As a hallmark, most TLPQC xenologues possess a core genome equivalent. With elevated temperature tolerance as a characteristic of clone C strains, the unique P. aeruginosa and clone C specific disaggregase ClpG is a major contributor to tolerance. As other successful clones, such as PA14, do not encode the TLPQC locus, ubiquitous denominators of success, if existing, need to be identified.
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Affiliation(s)
- Changhan Lee
- Department of Microbiology, Tumor and Cell Biology, Biomedicum C8, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - Jens Klockgether
- Clinic for Paediatric Pneumology, Allergology and Neonatology, Clinical Research Group 'Pseudomonas Genomics', Hannover Medical School, D-30625 Hannover, Germany
| | - Sebastian Fischer
- Clinic for Paediatric Pneumology, Allergology and Neonatology, Clinical Research Group 'Pseudomonas Genomics', Hannover Medical School, D-30625 Hannover, Germany
| | - Janja Trcek
- Faculty of Natural Sciences and Mathematics, Department of Biology, University of Maribor, Maribor, 2000, Slovenia
| | - Burkhard Tümmler
- Clinic for Paediatric Pneumology, Allergology and Neonatology, Clinical Research Group 'Pseudomonas Genomics', Hannover Medical School, D-30625 Hannover, Germany
| | - Ute Römling
- Department of Microbiology, Tumor and Cell Biology, Biomedicum C8, Karolinska Institutet, SE-171 77 Stockholm, Sweden
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Moriel B, de Campos Prediger K, de Souza EM, Pedrosa FO, Fadel-Picheth CMT, Cruz LM. In silico comparative analysis of Aeromonas Type VI Secretion System. Braz J Microbiol 2021; 52:229-243. [PMID: 33410103 DOI: 10.1007/s42770-020-00405-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 11/12/2020] [Indexed: 12/29/2022] Open
Abstract
Aeromonas are bacteria broadly spread in the environment, particularly in aquatic habitats and can induce human infections. Several virulence factors have been described associated with bacterial pathogenicity, such as the Type VI Secretion System (T6SS). This system translocates effector proteins into target cells through a bacteriophage-like contractile structure encoded by tss genes. Here, a total of 446 Aeromonas genome sequences were screened for T6SS and the proteins subjected to in silico analysis. The T6SS-encoding locus was detected in 243 genomes and its genes are encoded in a cluster containing 13 core and 5 accessory genes, in highly conserved synteny. The amino acid residues identity of T6SS proteins ranges from 78 to 98.8%. In most strains, a pair of tssD and tssI is located upstream the cluster (tssD-2, tssI-2) and another pair was detected distant from the cluster (tssD-1, tssI-1). Significant variability was seen in TssI (VgrG) C-terminal region, which was sorted in four groups based on its sequence length and protein domains. TssI containing ADP-ribosyltransferase domain are associated exclusively with TssI-1, while genes coding proteins carrying DUF4123 (a conserved domain of unknown function) were observed downstream tssI-1 or tssI-2 and escort of possible effector proteins. Genes coding proteins containing DUF1910 and DUF1911 domains were located only downstream tssI-2 and might represent a pair of toxin/immunity proteins. Nearly all strains display downstream tssI-3, that codes for a lysozyme family domain protein. These data reveal that Aeromonas T6SS cluster synteny is conserved and the low identity observed for some genes might be due to species heterogeneity or its niche/functionality.
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Affiliation(s)
- Barbara Moriel
- Department of Clinical Analysis, Setor de Ciências da Saúde, Curitiba, Brazil
| | | | - Emanuel M de Souza
- Department of Biochemistry and Molecular Biology, Setor de Ciências Biológicas, Curitiba, PR, Brazil
| | - Fábio O Pedrosa
- Department of Biochemistry and Molecular Biology, Setor de Ciências Biológicas, Curitiba, PR, Brazil
| | | | - Leonardo M Cruz
- Department of Biochemistry and Molecular Biology, Setor de Ciências Biológicas, Curitiba, PR, Brazil.
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Cajaninstilbene acid analogues as novel quorum sensing and biofilm inhibitors of Pseudomonas aeruginosa. Microb Pathog 2020; 148:104414. [DOI: 10.1016/j.micpath.2020.104414] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Revised: 05/20/2020] [Accepted: 07/21/2020] [Indexed: 01/09/2023]
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26
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González Plaza JJ. Small RNAs as Fundamental Players in the Transference of Information During Bacterial Infectious Diseases. Front Mol Biosci 2020; 7:101. [PMID: 32613006 PMCID: PMC7308464 DOI: 10.3389/fmolb.2020.00101] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2020] [Accepted: 05/04/2020] [Indexed: 12/24/2022] Open
Abstract
Communication shapes life on Earth. Transference of information has played a paramount role on the evolution of all living or extinct organisms since the appearance of life. Success or failure in this process will determine the prevalence or disappearance of a certain set of genes, the basis of Darwinian paradigm. Among different molecules used for transmission or reception of information, RNA plays a key role. For instance, the early precursors of life were information molecules based in primitive RNA forms. A growing field of research has focused on the contribution of small non-coding RNA forms due to its role on infectious diseases. These are short RNA species that carry out regulatory tasks in cis or trans. Small RNAs have shown their relevance in fine tuning the expression and activity of important regulators of essential genes for bacteria. Regulation of targets occurs through a plethora of mechanisms, including mRNA stabilization/destabilization, driving target mRNAs to degradation, or direct binding to regulatory proteins. Different studies have been conducted during the interplay of pathogenic bacteria with several hosts, including humans, animals, or plants. The sRNAs help the invader to quickly adapt to the change in environmental conditions when it enters in the host, or passes to a free state. The adaptation is achieved by direct targeting of the pathogen genes, or subversion of the host immune system. Pathogens trigger also an immune response in the host, which has been shown as well to be regulated by a wide range of sRNAs. This review focuses on the most recent host-pathogen interaction studies during bacterial infectious diseases, providing the perspective of the pathogen.
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Affiliation(s)
- Juan José González Plaza
- Faculty of Forestry and Wood Sciences, Czech University of Life Sciences Prague, Prague, Czechia
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Piewngam P, Chiou J, Chatterjee P, Otto M. Alternative approaches to treat bacterial infections: targeting quorum-sensing. Expert Rev Anti Infect Ther 2020; 18:499-510. [PMID: 32243194 PMCID: PMC11032741 DOI: 10.1080/14787210.2020.1750951] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 03/31/2020] [Indexed: 12/22/2022]
Abstract
Introduction: The emergence of multi- and pan-drug-resistant bacteria represents a global crisis that calls for the development of alternative anti-infective strategies. These comprise anti-virulence approaches, which target pathogenicity without exerting a bacteriostatic or bactericidal effect and are claimed to reduce the development of resistance. Because in many pathogens, quorum-sensing (QS) systems control the expression of virulence factors, interference with QS, or quorum-quenching, is often proposed as a strategy with a broad anti-virulence effect.Areas covered: We discuss the role and regulatory targets of QS control in selected Gram-positive and Gram-negative bacteria, focusing on those with clinical importance and QS control of virulence. We present the components of QS systems that form possible targets for the development of anti-virulence drugs and discuss recent research on quorum-quenching approaches to control bacterial infection.Expert opinion: While there has been extensive research on QS systems and quorum-quenching approaches, there is a paucity of in-vivo research using adequate animal models to substantiate applicability. In-vivo research on QS blockers needs to be intensified and optimized to use clinically relevant setups, in order to underscore that such drugs can be used effectively to overcome problems associated with the treatment of severe infections by antibiotic-resistant pathogens.
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Affiliation(s)
- Pipat Piewngam
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, U.S. National Institutes of Health, 50 South Drive, Bethesda, Maryland 20814, USA
| | - Janice Chiou
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, U.S. National Institutes of Health, 50 South Drive, Bethesda, Maryland 20814, USA
| | - Priyanka Chatterjee
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, U.S. National Institutes of Health, 50 South Drive, Bethesda, Maryland 20814, USA
| | - Michael Otto
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, U.S. National Institutes of Health, 50 South Drive, Bethesda, Maryland 20814, USA
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Abstract
Pseudomonas aeruginosa is a versatile bacterium found in various environments. It can cause severe infections in immunocompromised patients and naturally resists many antibiotics. The World Health Organization listed it among the top priority pathogens for research and development of new antimicrobial compounds. Quorum sensing (QS) is a cell-cell communication mechanism, which is important for P. aeruginosa adaptation and pathogenesis. Here, we validate the central role of the PqsE protein in QS particularly by its impact on the regulator RhlR. This study challenges the traditional dogmas of QS regulation in P. aeruginosa and ties loose ends in our understanding of the traditional QS circuit by confirming RhlR to be the main QS regulator in P. aeruginosa. PqsE could represent an ideal target for the development of new control methods against the virulence of P. aeruginosa. This is especially important when considering that LasR-defective mutants frequently arise, e.g., in chronic infections. The bacterium Pseudomonas aeruginosa has emerged as a central threat in health care settings and can cause a large variety of infections. It expresses an arsenal of virulence factors and a diversity of survival functions, many of which are finely and tightly regulated by an intricate circuitry of three quorum sensing (QS) systems. The las system is considered at the top of the QS hierarchy and activates the rhl and pqs systems. It is composed of the LasR transcriptional regulator and the LasI autoinducer synthase, which produces 3-oxo-C12-homoserine lactone (3-oxo-C12-HSL), the ligand of LasR. RhlR is the transcriptional regulator for the rhl system and is associated with RhlI, which produces its cognate autoinducer C4-HSL. The third QS system is composed of the pqsABCDE operon and the MvfR (PqsR) regulator. PqsABCD synthetize 4-hydroxy-2-alkylquinolines (HAQs), which include ligands activating MvfR. PqsE is not required for HAQ production and instead is associated with the expression of genes controlled by the rhl system. While RhlR is often considered the main regulator of rhlI, we confirmed that LasR is in fact the principal regulator of C4-HSL production and that RhlR regulates rhlI and production of C4-HSL essentially only in the absence of LasR by using liquid chromatography-mass spectrometry quantifications and gene expression reporters. Investigating the expression of RhlR targets also clarified that activation of RhlR-dependent QS relies on PqsE, especially when LasR is not functional. This work positions RhlR as the key QS regulator and points to PqsE as an essential effector for full activation of this regulation. IMPORTANCEPseudomonas aeruginosa is a versatile bacterium found in various environments. It can cause severe infections in immunocompromised patients and naturally resists many antibiotics. The World Health Organization listed it among the top priority pathogens for research and development of new antimicrobial compounds. Quorum sensing (QS) is a cell-cell communication mechanism, which is important for P. aeruginosa adaptation and pathogenesis. Here, we validate the central role of the PqsE protein in QS particularly by its impact on the regulator RhlR. This study challenges the traditional dogmas of QS regulation in P. aeruginosa and ties loose ends in our understanding of the traditional QS circuit by confirming RhlR to be the main QS regulator in P. aeruginosa. PqsE could represent an ideal target for the development of new control methods against the virulence of P. aeruginosa. This is especially important when considering that LasR-defective mutants frequently arise, e.g., in chronic infections.
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Pletzer D, Sun E, Ritchie C, Wilkinson L, Liu LT, Trimble MJ, Wolfmeier H, Blimkie TM, Hancock REW. Surfing motility is a complex adaptation dependent on the stringent stress response in Pseudomonas aeruginosa LESB58. PLoS Pathog 2020; 16:e1008444. [PMID: 32208458 PMCID: PMC7122816 DOI: 10.1371/journal.ppat.1008444] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2019] [Revised: 04/03/2020] [Accepted: 02/29/2020] [Indexed: 11/18/2022] Open
Abstract
Cystic fibrosis (CF) is a genetic disease that affects mucin-producing body organs such as the lungs. Characteristic of CF is the production of thick, viscous mucus, containing the glycoprotein mucin, that can lead to progressive airway obstruction. Recently, we demonstrated that the presence of mucin induced a rapid surface adaptation in motile bacteria termed surfing motility, which data presented here indicates is very different from swarming motility. Pseudomonas aeruginosa, the main colonizing pathogen in CF, employs several stress coping mechanisms to survive the highly viscous environment of the CF lung. We used motility-based assays and RNA-Seq to study the stringent stress response in the hypervirulent CF isolate LESB58 (Liverpool Epidemic Strain). Motility experiments revealed that an LESB58 stringent response mutant (ΔrelAΔspoT) was unable to surf. Transcriptional profiling of ΔrelAΔspoT mutant cells from surfing agar plates, when compared to wild-type cells from the surfing edge, revealed 2,584 dysregulated genes. Gene Ontology and KEGG enrichment analysis revealed effects of the stringent response on amino acid, nucleic acid and fatty acid metabolism, TCA cycle and glycolysis, type VI secretion, as well as chemotaxis, cell communication, iron transport, nitrogen metabolic processes and cyclic-di-GMP signalling. Screening of the ordered PA14 transposon library revealed 224 mutants unable to surf and very limited overlap with genes required for swarming. Mutants affecting surfing included two downstream effector genes of the stringent stress response, the copper regulator cueR and the quinolone synthase pqsH. Both the cueR and pqsH cloned genes complemented the surfing deficiency of ΔrelAΔspoT. Our study revealed insights into stringent stress dependency in LESB58 and showed that surfing motility is stringently-controlled via the expression of cueR and pqsH. Downstream factors of the stringent stress response are important to investigate in order to fully understand its ability to colonize and persist in the CF lung.
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Affiliation(s)
- Daniel Pletzer
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
- * E-mail: (DP); (REWH)
| | - Evelyn Sun
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
| | - Caleb Ritchie
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
| | - Lauren Wilkinson
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
| | - Leo T. Liu
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
| | - Michael J. Trimble
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
| | - Heidi Wolfmeier
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
| | - Travis M. Blimkie
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
| | - Robert E. W. Hancock
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
- * E-mail: (DP); (REWH)
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30
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Kirchhoff L, Weisner AK, Schrepffer M, Hain A, Scharmann U, Buer J, Rath PM, Steinmann J. Phenotypical Characteristics of the Black Yeast Exophiala dermatitidis Are Affected by Pseudomonas aeruginosa in an Artificial Sputum Medium Mimicking Cystic Fibrosis-Like Conditions. Front Microbiol 2020; 11:471. [PMID: 32265891 PMCID: PMC7100538 DOI: 10.3389/fmicb.2020.00471] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 03/04/2020] [Indexed: 12/18/2022] Open
Abstract
Research into the cooperative pathogenicity of microbes in cystic fibrosis (CF) lungs is crucial for an understanding of the pathophysiology of infections and the development of novel treatment strategies. This study investigated the impact of the common CF-associated bacterial pathogen Pseudomonas aeruginosa on the black yeast Exophiala dermatitidis. It evaluated the planktonic growth, biofilm formation, morphology, and virulence of the fungus in the presence or absence of P. aeruginosa. It also determined the role of P. aeruginosa quorum-sensing (QS) molecules within these interactions, e.g., by using sterile culture filtrate and QS-deficient mutants. P. aeruginosa is known to inhibit the planktonic growth of E. dermatitidis. We found that fungal biofilm formation increased in the presence of P. aeruginosa after 24 h but is decreased significantly after 48 h. This effect was reversed when, instead of QS wild-type strains, ΔlasR, and ΔrhlR mutants were added to E. dermatitidis biofilm formation. The number and length of hyphae were substantially reduced when E. dermatitidis was co-cultivated with P. aeruginosa, but not when it was co-cultivated with the mutants. Experiments testing the virulence of E. dermatitidis in the greater wax moth Galleria mellonella showed a synergetic effect on larval killing when E. dermatitidis was injected together with P. aeruginosa culture filtrate. Survival rates were decreased when biofilm culture filtrate was added but not when planktonic culture filtrate was added. In summary, P. aeruginosa affects the growth, morphology, biofilm formation, and virulence of E. dermatitidis. N-acyl-L-homoserine lactone (AHL) QS molecules regulated factors that have been shown to contribute to the inhibition of the ability of E. dermatitidis to form filaments and biofilm.
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Affiliation(s)
- Lisa Kirchhoff
- Institute of Medical Microbiology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Ann-Kathrin Weisner
- Institute of Medical Microbiology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Mona Schrepffer
- Institute of Medical Microbiology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Andrea Hain
- Institute of Medical Microbiology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Ulrike Scharmann
- Institute of Medical Microbiology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Jan Buer
- Institute of Medical Microbiology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Peter-Michael Rath
- Institute of Medical Microbiology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Joerg Steinmann
- Institute of Medical Microbiology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany.,Institute of Clinical Hygiene, Medical Microbiology and Infectiology, Klinikum Nürnberg, Paracelsus Medical University, Nuremberg, Germany
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31
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Mohamed B, Abdel-Samii ZK, Abdel-Aal EH, Abbas HA, Shaldam MA, Ghanim AM. Synthesis of imidazolidine-2,4-dione and 2-thioxoimidazolidin-4-one derivatives as inhibitors of virulence factors production in Pseudomonas aeruginosa. Arch Pharm (Weinheim) 2020; 353:e1900352. [PMID: 32134150 DOI: 10.1002/ardp.201900352] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 02/11/2020] [Accepted: 02/13/2020] [Indexed: 12/19/2022]
Abstract
In an attempt to counteract bacterial pathogenicity, a set of novel imidazolidine-2,4-dione and 2-thioxoimidazolidin-4-one derivatives was synthesized and evaluated as inhibitors of bacterial virulence. The new compounds were characterized and screened for their effects on the expression of virulence factors of Pseudomonas aeruginosa, including protease, hemolysin, and pyocyanin. Imidazolidine-2,4-diones 4c, 4j, and 12a showed complete inhibition of the protease enzyme, and they almost completely inhibited the production of hemolysin at 1/4 MIC (1/4 minimum inhibitory concentration; 1, 0.5, and 0.5 mg/ml, respectively). 2-Thioxoimidazolidin-4-one derivative 7a exhibited the best inhibitory activity (96.4%) against pyocyanin production at 1 mg/ml (1/4 MIC). A docking study was preformed to explore the potential binding interactions with quorum-sensing receptors (LasR and RhlR), which are responsible for the expression of virulence genes.
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Affiliation(s)
- Basant Mohamed
- Department of Pharmaceutical Organic Chemistry, Faculty of Pharmacy, Zagazig University, Zagazig, Egypt
| | - Zakaria K Abdel-Samii
- Department of Pharmaceutical Organic Chemistry, Faculty of Pharmacy, Zagazig University, Zagazig, Egypt
| | - Eatedal H Abdel-Aal
- Department of Pharmaceutical Organic Chemistry, Faculty of Pharmacy, Zagazig University, Zagazig, Egypt
| | - Hisham A Abbas
- Department of Microbiology and Immunology, Faculty of Pharmacy, Zagazig University, Zagazig, Egypt
| | - Moataz A Shaldam
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Kafrelsheikh University, Kafrelsheikh, Egypt
| | - Amany M Ghanim
- Department of Pharmaceutical Organic Chemistry, Faculty of Pharmacy, Zagazig University, Zagazig, Egypt
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García-Reyes S, Soberón-Chávez G, Cocotl-Yanez M. The third quorum-sensing system of Pseudomonas aeruginosa: Pseudomonas quinolone signal and the enigmatic PqsE protein. J Med Microbiol 2020; 69:25-34. [PMID: 31794380 DOI: 10.1099/jmm.0.001116] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that produces several virulence factors such as lectin A, pyocyanin, elastase and rhamnolipids. These compounds are controlled transcriptionally by three quorum-sensing circuits, two based on the synthesis and detection of N-acyl-homoserine-lactone termed the Las and Rhl system and a third system named the Pseudomonas quinolone signal (PQS) system, which is responsible for generating 2-alkyl-4(1 h)-quinolones (AQs). The transcriptional regulator called PqsR binds to the promoter of pqsABCDE in the presence of PQS or HHQ creating a positive feedback-loop. PqsE, encoded in the operon for AQ synthesis, is a crucial protein for pyocyanin production, activating the Rhl system by a still not fully understood mechanism. In turn, the regulation of the PQS system is modulated by Las and Rhl systems, which act positively and negatively, respectively. This review focuses on the PQS system, from its discovery to its role in Pseudomonas pathogenesis, such as iron depletion and pyocyanin synthesis that involves the PqsE protein - an intriguing player of this system.
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Affiliation(s)
- Selene García-Reyes
- Departamento de Biología molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, Apdo Postal 70228, C.P. 04510, Ciudad de México, Mexico
| | - Gloria Soberón-Chávez
- Departamento de Biología molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, Apdo Postal 70228, C.P. 04510, Ciudad de México, Mexico
| | - Miguel Cocotl-Yanez
- Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México. Av. Universidad 3000, Cd. Universitaria, C.P. 04510, Coyoacán, Ciudad de México, Mexico
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Chakravarty S, Massé E. RNA-Dependent Regulation of Virulence in Pathogenic Bacteria. Front Cell Infect Microbiol 2019; 9:337. [PMID: 31649894 PMCID: PMC6794450 DOI: 10.3389/fcimb.2019.00337] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 09/18/2019] [Indexed: 12/19/2022] Open
Abstract
During infection, bacterial pathogens successfully sense, respond and adapt to a myriad of harsh environments presented by the mammalian host. This exquisite level of adaptation requires a robust modulation of their physiological and metabolic features. Additionally, virulence determinants, which include host invasion, colonization and survival despite the host's immune responses and antimicrobial therapy, must be optimally orchestrated by the pathogen at all times during infection. This can only be achieved by tight coordination of gene expression. A large body of evidence implicate the prolific roles played by bacterial regulatory RNAs in mediating gene expression both at the transcriptional and post-transcriptional levels. This review describes mechanistic and regulatory aspects of bacterial regulatory RNAs and highlights how these molecules increase virulence efficiency in human pathogens. As illustrative examples, Staphylococcus aureus, Listeria monocytogenes, the uropathogenic strain of Escherichia coli, Helicobacter pylori, and Pseudomonas aeruginosa have been selected.
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Affiliation(s)
- Shubham Chakravarty
- RNA Group, Department of Biochemistry, Faculty of Medicine and Health Sciences, CRCHUS, University of Sherbrooke, Sherbrooke, QC, Canada
| | - Eric Massé
- RNA Group, Department of Biochemistry, Faculty of Medicine and Health Sciences, CRCHUS, University of Sherbrooke, Sherbrooke, QC, Canada
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34
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Reen FJ, McGlacken GP, O'Gara F. The expanding horizon of alkyl quinolone signalling and communication in polycellular interactomes. FEMS Microbiol Lett 2019; 365:4953739. [PMID: 29718276 DOI: 10.1093/femsle/fny076] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 03/25/2018] [Indexed: 02/07/2023] Open
Abstract
Population dynamics within natural ecosystems is underpinned by microbial diversity and the heterogeneity of host-microbe and microbe-microbe interactions. Small molecule signals that intersperse between species have been shown to govern many virulence-related processes in established and emerging pathogens. Understanding the capacity of microbes to decode diverse languages and adapt to the presence of 'non-self' cells will provide an important new direction to the understanding of the 'polycellular' interactome. Alkyl quinolones (AQs) have been described in the ESKAPE pathogen Pseudomonas aeruginosa, the primary agent associated with mortality in patients with cystic fibrosis and the third most prevalent nosocomial pathogen worldwide. The role of these molecules in governing the physiology and virulence of P. aeruginosa and other pathogens has received considerable attention, while a role in interspecies and interkingdom communication has recently emerged. Herein we discuss recent advances in our understanding of AQ signalling and communication in the context of microbe-microbe and microbe-host interactions. The integrated knowledge from these systems-based investigations will facilitate the development of new therapeutics based on the AQ framework that serves to disarm the pathogenesis of P. aeruginosa and competing pathogens.
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Affiliation(s)
- F Jerry Reen
- School of Microbiology, University College Cork, Cork, Ireland
| | - Gerard P McGlacken
- School of Chemistry and Analytical & Biological Chemistry Research Facility (ABCRF), University College Cork, Ireland
| | - Fergal O'Gara
- BIOMERIT Research Centre, School of Microbiology, University College Cork, Cork, Ireland
- Human Microbiome Programme, School of Pharmacy and Biomedical Sciences, Curtin Health Innovation Research Institute, Curtin University, Perth, WA 6102, USA
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Differential effects of alkyl gallates on quorum sensing in Pseudomonas aeruginosa. Sci Rep 2019; 9:7741. [PMID: 31123307 PMCID: PMC6533263 DOI: 10.1038/s41598-019-44236-w] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 05/13/2019] [Indexed: 02/07/2023] Open
Abstract
Virulence factors and biofilms constitute attractive targets for the prevention of infections caused by multidrug-resistant bacteria. Among alkyl gallates, propyl gallate (PG) and octyl gallate (OG) are used as food preservatives. Here we found that alkyl gallates differentially affect virulence, biofilm formation, and quorum sensing (QS) in Pseudomonas aeruginosa. Ethyl gallate (EG), PG, and butyl gallate (BG) inhibited biofilm formation and virulence factors including elastase, pyocyanin, and rhamnolipid, in P. aeruginosa without affecting cell viability by antagonizing the QS receptors LasR and RhlR. PG exhibited the most potent activity. Interestingly, hexyl gallate (HG) inhibited the production of rhamnolipid and pyocyanin but did not affect elastase production or biofilm formation. Notably, OG inhibited the production of rhamnolipid and pyocyanin but stimulated elastase production and biofilm formation. Analysis of QS signaling molecule production and QS gene expression suggested that HG inhibited RhlR, while OG activated LasR but inhibited PqsR. This mechanism was confirmed using QS mutants. Additionally, PG prevented the virulence of P. aeruginosa in Caenorhabditis elegans and a mouse model. This is the first report of the differential effects of alkyl gallates on QS systems and PG has great potential as an inhibitor of the virulence and biofilm formation of P. aeruginosa.
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Xu XJ, Zeng T, Huang ZX, Xu XF, Lin J, Chen WM. Synthesis and Biological Evaluation of Cajaninstilbene Acid and Amorfrutins A and B as Inhibitors of the Pseudomonas aeruginosa Quorum Sensing System. JOURNAL OF NATURAL PRODUCTS 2018; 81:2621-2629. [PMID: 30444360 DOI: 10.1021/acs.jnatprod.8b00315] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The quorum sensing (QS) system inhibitors of Pseudomonas aeruginosa are thought to attenuate bacterial pathogenicity and drug resistance by inhibiting biofilm formation and the production of virulence factors. In this study, a synthetic approach to the natural products cajaninstilbene acid (1) and amorfrutins A (2) and B (3) has been developed and was characterized by the Heck reaction, which was used to obtain the stilbene core and a Pinick oxidation to give the O-hydroxybenzoic acid. The biological activities of these compounds against the P. aeruginosa quorum sensing systems were evaluated. Amorfrutin B (3) showed promising antibiofilm activity against P. aeruginosa PAO1 with a biofilm inhibition ratio of 50.3 ± 2.7. Three lacZ reporter strains were constructed to identify the effects of compound 3 on different QS systems. Suppression efficacy of compound 3 on the expression of lasB-lacZ and pqsA-lacZ as well as on the production of their corresponding virulence factors elastase and pyocyanin was observed.
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Affiliation(s)
- Xing-Jun Xu
- College of Pharmacy , Jinan University , Guangzhou 510632 , People's Republic of China
| | - Ting Zeng
- College of Pharmacy , Jinan University , Guangzhou 510632 , People's Republic of China
| | - Zhi-Xing Huang
- College of Pharmacy , Jinan University , Guangzhou 510632 , People's Republic of China
| | - Xiao-Fang Xu
- College of Pharmacy , Jinan University , Guangzhou 510632 , People's Republic of China
| | - Jing Lin
- College of Pharmacy , Jinan University , Guangzhou 510632 , People's Republic of China
| | - Wei-Min Chen
- College of Pharmacy , Jinan University , Guangzhou 510632 , People's Republic of China
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D'Angelo F, Baldelli V, Halliday N, Pantalone P, Polticelli F, Fiscarelli E, Williams P, Visca P, Leoni L, Rampioni G. Identification of FDA-Approved Drugs as Antivirulence Agents Targeting the pqs Quorum-Sensing System of Pseudomonas aeruginosa. Antimicrob Agents Chemother 2018; 62:e01296-18. [PMID: 30201815 PMCID: PMC6201120 DOI: 10.1128/aac.01296-18] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 09/01/2018] [Indexed: 12/11/2022] Open
Abstract
The long-term use of antibiotics has led to the emergence of multidrug-resistant bacteria. A promising strategy to combat bacterial infections aims at hampering their adaptability to the host environment without affecting growth. In this context, the intercellular communication system quorum sensing (QS), which controls virulence factor production and biofilm formation in diverse human pathogens, is considered an ideal target. Here, we describe the identification of new inhibitors of the pqs QS system of the human pathogen Pseudomonas aeruginosa by screening a library of 1,600 U.S. Food and Drug Administration-approved drugs. Phenotypic characterization of ad hoc engineered strains and in silico molecular docking demonstrated that the antifungal drugs clotrimazole and miconazole, as well as an antibacterial compound active against Gram-positive pathogens, clofoctol, inhibit the pqs system, probably by targeting the transcriptional regulator PqsR. The most active inhibitor, clofoctol, specifically inhibited the expression of pqs-controlled virulence traits in P. aeruginosa, such as pyocyanin production, swarming motility, biofilm formation, and expression of genes involved in siderophore production. Moreover, clofoctol protected Galleria mellonella larvae from P. aeruginosa infection and inhibited the pqs QS system in P. aeruginosa isolates from cystic fibrosis patients. Notably, clofoctol is already approved for clinical treatment of pulmonary infections caused by Gram-positive bacterial pathogens; hence, this drug has considerable clinical potential as an antivirulence agent for the treatment of P. aeruginosa lung infections.
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Affiliation(s)
| | | | - Nigel Halliday
- Centre for Biomolecular Sciences and School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Paolo Pantalone
- Centre for Biomolecular Sciences and School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Fabio Polticelli
- Department of Science, University Roma Tre, Rome, Italy
- National Institute of Nuclear Physics, Roma Tre Section, Rome, Italy
| | - Ersilia Fiscarelli
- Laboratory of Cystic Fibrosis Microbiology, Bambino Gesú Hospital, Rome, Italy
| | - Paul Williams
- Centre for Biomolecular Sciences and School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Paolo Visca
- Department of Science, University Roma Tre, Rome, Italy
| | - Livia Leoni
- Department of Science, University Roma Tre, Rome, Italy
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Thi Bach Nguyen H, Romero A D, Amman F, Sorger-Domenigg T, Tata M, Sonnleitner E, Bläsi U. Negative Control of RpoS Synthesis by the sRNA ReaL in Pseudomonas aeruginosa. Front Microbiol 2018; 9:2488. [PMID: 30420839 PMCID: PMC6215814 DOI: 10.3389/fmicb.2018.02488] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 09/28/2018] [Indexed: 12/13/2022] Open
Abstract
Pseudomonas aeruginosa (Pae) is an opportunistic human pathogen, able to resist host defense mechanisms and antibiotic treatment. In Pae, the master regulator of stress responses RpoS (σS) is involved in the regulation of quorum sensing and several virulence genes. Here, we report that the sRNA ReaL translationally silences rpoS mRNA, which results in a decrease of the RpoS levels. Our studies indicated that ReaL base-pairs with the Shine-Dalgarno region of rpoS mRNA. These studies are underlined by a highly similar transcription profile of a rpoS deletion mutant and a reaL over-expressing strain.
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Affiliation(s)
- Hue Thi Bach Nguyen
- Department of Microbiology, Immunobiology and Genetics, Max F. Perutz Laboratories, Center of Molecular Biology, University of Vienna - Vienna Biocenter, Vienna, Austria
| | - David Romero A
- Department of Microbiology, Immunobiology and Genetics, Max F. Perutz Laboratories, Center of Molecular Biology, University of Vienna - Vienna Biocenter, Vienna, Austria
| | - Fabian Amman
- Institute of Theoretical Chemistry, University of Vienna, Vienna, Austria
| | - Theresa Sorger-Domenigg
- Department of Microbiology, Immunobiology and Genetics, Max F. Perutz Laboratories, Center of Molecular Biology, University of Vienna - Vienna Biocenter, Vienna, Austria
| | - Muralidhar Tata
- Department of Microbiology, Immunobiology and Genetics, Max F. Perutz Laboratories, Center of Molecular Biology, University of Vienna - Vienna Biocenter, Vienna, Austria
| | - Elisabeth Sonnleitner
- Department of Microbiology, Immunobiology and Genetics, Max F. Perutz Laboratories, Center of Molecular Biology, University of Vienna - Vienna Biocenter, Vienna, Austria
| | - Udo Bläsi
- Department of Microbiology, Immunobiology and Genetics, Max F. Perutz Laboratories, Center of Molecular Biology, University of Vienna - Vienna Biocenter, Vienna, Austria
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Higgins S, Heeb S, Rampioni G, Fletcher MP, Williams P, Cámara M. Differential Regulation of the Phenazine Biosynthetic Operons by Quorum Sensing in Pseudomonas aeruginosa PAO1-N. Front Cell Infect Microbiol 2018; 8:252. [PMID: 30083519 PMCID: PMC6064868 DOI: 10.3389/fcimb.2018.00252] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 07/03/2018] [Indexed: 01/26/2023] Open
Abstract
The Pseudomonas aeruginosa quorum sensing (QS) network plays a key role in the adaptation to environmental changes and the control of virulence factor production in this opportunistic human pathogen. Three interlinked QS systems, namely las, rhl, and pqs, are central to the production of pyocyanin, a phenazine virulence factor which is typically used as phenotypic marker for analysing QS. Pyocyanin production in P. aeruginosa is a complex process involving two almost identical operons termed phzA1B1C1D1E1F1G1 (phz1) and phzA2B2C2D2E2F2G2 (phz2), which drive the production of phenazine-1-carboxylic acid (PCA) which is further converted to pyocyanin by two modifying enzymes PhzM and PhzS. Due to the high sequence conservation between the phz1 and phz2 operons (nucleotide identity > 98%), analysis of their individual expression by RNA hybridization, qRT-PCR or transcriptomics is challenging. To overcome this difficulty, we utilized luminescence based promoter fusions of each phenazine operon to measure in planktonic cultures their transcriptional activity in P. aeruginosa PAO1-N genetic backgrounds impaired in different components of the las, rhl, and pqs QS systems, in the presence or absence of different QS signal molecules. Using this approach, we found that all three QS systems play a role in differentially regulating the phz1 and phz2 phenazine operons, thus uncovering a higher level of complexity to the QS regulation of PCA biosynthesis in P. aeruginosa than previously appreciated. Importance The way the P. aeruginosa QS regulatory networks are intertwined creates a challenge when analysing the mechanisms governing specific QS-regulated traits. Multiple QS regulators and signals have been associated with the production of phenazine virulence factors. In this work we designed experiments where we dissected the contribution of specific QS switches using individual mutations and complementation strategies to gain further understanding of the specific roles of these QS elements in controlling expression of the two P. aeruginosa phenazine operons. Using this approach we have teased out which QS regulators have either indirect or direct effects on the regulation of the two phenazine biosynthetic operons. The data obtained highlight the sophistication of the QS cascade in P. aeruginosa and the challenges in analysing the control of phenazine secondary metabolites.
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Affiliation(s)
- Steven Higgins
- Centre for Biomolecular Science, School of Life Science, University of Nottingham, Nottingham, United Kingdom
- Department of Plant and Microbial Biology, University of Zürich, Zurich, Switzerland
| | - Stephan Heeb
- Centre for Biomolecular Science, School of Life Science, University of Nottingham, Nottingham, United Kingdom
| | - Giordano Rampioni
- Centre for Biomolecular Science, School of Life Science, University of Nottingham, Nottingham, United Kingdom
- Department of Science, University Roma Tre, Rome, Italy
| | - Mathew P. Fletcher
- Centre for Biomolecular Science, School of Life Science, University of Nottingham, Nottingham, United Kingdom
| | - Paul Williams
- Centre for Biomolecular Science, School of Life Science, University of Nottingham, Nottingham, United Kingdom
| | - Miguel Cámara
- Centre for Biomolecular Science, School of Life Science, University of Nottingham, Nottingham, United Kingdom
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40
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Jagmann N, Philipp B. SpoT-Mediated Regulation and Amino Acid Prototrophy Are Essential for Pyocyanin Production During Parasitic Growth of Pseudomonas aeruginosa in a Co-culture Model System With Aeromonas hydrophila. Front Microbiol 2018; 9:761. [PMID: 29720972 PMCID: PMC5915560 DOI: 10.3389/fmicb.2018.00761] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 04/04/2018] [Indexed: 11/17/2022] Open
Abstract
The opportunistic pathogen Pseudomonas aeruginosa employs its complex quorum sensing (QS) network to regulate the expression of virulence factors such as pyocyanin. Besides cell density, QS in this bacterium is co-regulated by environmental cues. In this study, we employed a previously established co-culture model system to identify metabolic influences that are involved in the regulation of pyocyanin production in P. aeruginosa. In this co-culture consisting of P. aeruginosa and the chitinolytic bacterium Aeromonas hydrophila, parasitic growth of P. aeruginosa is strictly dependent on the production of pyocyanin. We could show that in this co-culture, pyocyanin production is likely induced by the stringent response mediated by SpoT in response to nutrient limitation. Pyocyanin production by stringent response mutants in the co-culture could not be complemented by overexpression of PqsE. Via transposon mutagenesis, several amino acid auxotrophic mutants were identified that were also unable to produce pyocyanin when PqsE was overexpressed or when complementing amino acids were present. The inability to produce pyocyanin even though PqsE was overexpressed was likely a general effect of amino acid auxotrophy. These results show the value of the co-culture approach to identify both extra- and intracellular metabolic influences on QS that might be important in infection processes as well.
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Affiliation(s)
- Nina Jagmann
- Institute for Molecular Microbiology and Biotechnology, University of Münster, Münster, Germany
| | - Bodo Philipp
- Institute for Molecular Microbiology and Biotechnology, University of Münster, Münster, Germany
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41
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Baker YR, Hodgkinson JT, Florea BI, Alza E, Galloway WRJD, Grimm L, Geddis SM, Overkleeft HS, Welch M, Spring DR. Identification of new quorum sensing autoinducer binding partners in Pseudomonas aeruginosa using photoaffinity probes. Chem Sci 2017; 8:7403-7411. [PMID: 29163891 PMCID: PMC5674140 DOI: 10.1039/c7sc01270e] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Accepted: 08/26/2017] [Indexed: 12/20/2022] Open
Abstract
Many bacterial species, including the human pathogen Pseudomonas aeruginosa, employ a mechanism of intercellular communication known as quorum sensing (QS), which is mediated by signalling molecules termed autoinducers. The Pseudomonas Quinolone Signal (PQS) and 2-Heptyl-3H-4-Quinolone (HHQ) are autoinducers in P. aeruginosa, and they are considered important factors in the progress of infections by this clinically relevant organism. Herein, we report the development of HHQ and PQS photoaffinity-based probes for chemical proteomic studies. Application of these probes led to the identification of previously unsuspected putative HHQ and PQS binders, thereby providing new insights into QS at a proteomic level and revealing potential new small molecule targets for virulence attenuation strategies. Notably, we found evidence that PQS binds RhlR, the cognate receptor in the Rhl QS sub-system of P. aeruginosa. This is the first indication of interaction between the Rhl and PQS systems at the protein/ligand level, which suggests that RhlR should be considered a highly attractive target for antivirulence strategies.
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Affiliation(s)
- Y R Baker
- Department of Chemistry , University of Cambridge , Lensfield Road , Cambridge , CB2 1EW , UK .
- Leiden Institute of Chemistry , Leiden University , Einsteinweg 55 , 2333 CC Leiden , The Netherlands
- Department of Biochemistry , University of Cambridge , 80 Tennis Court Road , Cambridge , CB2 1GA , UK .
| | - J T Hodgkinson
- Department of Chemistry , University of Cambridge , Lensfield Road , Cambridge , CB2 1EW , UK .
- Department of Biochemistry , University of Cambridge , 80 Tennis Court Road , Cambridge , CB2 1GA , UK .
| | - B I Florea
- Leiden Institute of Chemistry , Leiden University , Einsteinweg 55 , 2333 CC Leiden , The Netherlands
| | - E Alza
- Department of Chemistry , University of Cambridge , Lensfield Road , Cambridge , CB2 1EW , UK .
| | - W R J D Galloway
- Department of Chemistry , University of Cambridge , Lensfield Road , Cambridge , CB2 1EW , UK .
| | - L Grimm
- Department of Biochemistry , University of Cambridge , 80 Tennis Court Road , Cambridge , CB2 1GA , UK .
| | - S M Geddis
- Department of Chemistry , University of Cambridge , Lensfield Road , Cambridge , CB2 1EW , UK .
| | - H S Overkleeft
- Leiden Institute of Chemistry , Leiden University , Einsteinweg 55 , 2333 CC Leiden , The Netherlands
| | - M Welch
- Department of Biochemistry , University of Cambridge , 80 Tennis Court Road , Cambridge , CB2 1GA , UK .
| | - D R Spring
- Department of Chemistry , University of Cambridge , Lensfield Road , Cambridge , CB2 1EW , UK .
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Turnpenny P, Padfield A, Barton P, Teague J, Rahme LG, Pucci MJ, Zahler R, Rubio A. Bioanalysis of Pseudomonas aeruginosa alkyl quinolone signalling molecules in infected mouse tissue using LC-MS/MS; and its application to a pharmacodynamic evaluation of MvfR inhibition. J Pharm Biomed Anal 2017; 139:44-53. [PMID: 28273650 DOI: 10.1016/j.jpba.2017.02.034] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 02/16/2017] [Indexed: 10/20/2022]
Abstract
Alkyl quinolone molecules 2-heptyl-4-quinolone (HHQ) and 2-heptyl-3-hydroxy-4(1H)-quinolone (PQS) are important quorum sensing signals, which play a mediatory role in the pathogenesis of acute and chronic Pseudomonas aeruginosa infection. A targeted approach inhibiting the bacterial 'multiple virulence factor regulon' (MvfR) protein complex, offers the possibility to block the synthesis of MvfR-dependant signal molecules. Here, a high throughput bioanalytical method was developed using LC-MS/MS detection for the selective determination of HHQ and PQS in mouse tissue homogenate, over a sensitive range of 1-5000 and 10-5000pg/mL, respectively. Chromatographic peak distortion of the iron chelator PQS was overcome with the applied use of a bidentate chelator mobile phase additive 2-Picolinic acid at 0.2mM concentration, giving an improved separation and response for the analyte, whilst maintaining overall MS system robustness. Following thigh infection with P. aeruginosa strain 2-PA14 in mice, the concentration and time course of HHQ and PQS (4-hydroxy-2-alkyl-quinolone (HAQ) biomarkers) residing in the biophase were evaluated, and exhibited a low level combined with a substantial inter-individual variability. Quantifiable levels could be obtained from approximately 15h post infection, to the study termination at 21-22h. A dose dependant reduction in HAQ tissue concentrations at selected time points were obtained following MvfR inhibitor administration versus drug vehicle (p<0.01, Kruskal-Wallis-one way ANOVA) and meta -analyses of several studies enabled an inhibitory concentration (IC50) of 80nM free drug to be determined. However, due to the experimental limitations a defined time profile for in-vivo HAQ production could not be characterised. Microsomal stability measurements demonstrated a rapid metabolic clearance of both alkyl quinolone biomarkers in the bacterial host, with a hepatic extraction ratio greater than 0.96 (the measurable assay limit). High clearance underpinned the low concentrations present in the well-perfused thigh tissue. Along with method development and validation details, this paper considers the kinetics of in-vivo HAQ bio-synthesis during Pseudomonas infection; and risks of biomarker over-estimation from samples which contain an exogenous population of bacteria.
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Affiliation(s)
- Paul Turnpenny
- Evotec, Drug Metabolism and Pharmacokinetics Department, Abingdon, Oxon, United Kingdom.
| | - Anthony Padfield
- Evotec, Drug Metabolism and Pharmacokinetics Department, Abingdon, Oxon, United Kingdom
| | - Patrick Barton
- Evotec, Drug Metabolism and Pharmacokinetics Department, Abingdon, Oxon, United Kingdom
| | - Joanne Teague
- Evotec, Anti-infective Research Unit, Manchester, United Kingdom
| | - Laurence G Rahme
- Department of Surgery, Massachusetts General Hospital, Boston, MA, United States; Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA, United States; Shriners Hospitals for Children, Boston, MA, United States
| | | | | | - Aileen Rubio
- Spero Therapeutics, Cambridge, MA, United States
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43
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Farrow JM, Pesci EC. Distal and proximal promoters co-regulate pqsR expression in Pseudomonas aeruginosa. Mol Microbiol 2017; 104:78-91. [PMID: 28010047 DOI: 10.1111/mmi.13611] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/18/2016] [Indexed: 01/27/2023]
Abstract
The ubiquitous bacterium Pseudomonas aeruginosa is an opportunistic pathogen that can cause serious infections in immunocompromised individuals. P. aeruginosa virulence is controlled partly by intercellular communication, and the transcription factor PqsR is a necessary component in the P. aeruginosa cell-to-cell signaling network. PqsR acts as the receptor for the Pseudomonas quinolone signal, and it controls the production of 2-alkyl-4-quinolone molecules which are important for pathogenicity. Previous studies showed that the expression of pqsR is positively controlled by the quorum-sensing regulator LasR, but it was unclear how LasR is able to induce pqsR transcription. In this report, we further investigated the control of pqsR, and discovered two separate promoter sites that contribute to pqsR expression. LasR-mediated activation occurs at the distal promoter site, but this activation can be antagonized by the regulator CysB. The proximal promoter site also contributes to pqsR transcription, but initiation at this site is inhibited by a negative regulatory sequence element, and potentially by the H-NS family members MvaT and MvaU. We propose a model where positive and negative regulatory influences at each promoter site are integrated to modify pqsR expression. This arrangement could allow for information from both environmental signals and cell-to-cell communication to influence PqsR levels.
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Affiliation(s)
- John M Farrow
- Department of Microbiology and Immunology, The Brody School of Medicine at East Carolina University, 600 Moye Blvd, Greenville, NC, 27834, USA
| | - Everett C Pesci
- Department of Microbiology and Immunology, The Brody School of Medicine at East Carolina University, 600 Moye Blvd, Greenville, NC, 27834, USA
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RpoN Modulates Carbapenem Tolerance in Pseudomonas aeruginosa through Pseudomonas Quinolone Signal and PqsE. Antimicrob Agents Chemother 2016; 60:5752-64. [PMID: 27431228 DOI: 10.1128/aac.00260-16] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2016] [Accepted: 07/05/2016] [Indexed: 01/09/2023] Open
Abstract
The ability of Pseudomonas aeruginosa to rapidly modulate its response to antibiotic stress and persist in the presence of antibiotics is closely associated with the process of cell-to-cell signaling. The alternative sigma factor RpoN (σ(54)) is involved in the regulation of quorum sensing (QS) and plays an important role in the survival of stationary-phase cells in the presence of carbapenems. Here, we demonstrate that a ΔrpoN mutant grown in nutrient-rich medium has increased expression of pqsA, pqsH, and pqsR throughout growth, resulting in the increased production of the Pseudomonas quinolone signal (PQS). The link between pqsA and its role in carbapenem tolerance was studied using a ΔrpoN ΔpqsA mutant, in which the carbapenem-tolerant phenotype of the ΔrpoN mutant was abolished. In addition, we demonstrate that another mechanism leading to carbapenem tolerance in the ΔrpoN mutant is mediated through pqsE Exogenously supplied PQS abolished the biapenem-sensitive phenotype of the ΔrpoN ΔpqsA mutant, and overexpression of pqsE failed to alter the susceptibility of the ΔrpoN ΔpqsA mutant to biapenem. The mutations in the ΔrpoN ΔrhlR mutant and the ΔrpoN ΔpqsH mutant led to susceptibility to biapenem. Comparison of the changes in the expression of the genes involved in QS in wild-type PAO1 with their expression in the ΔrpoN mutant and the ΔrpoN mutant-derived strains demonstrated the regulatory effect of RpoN on the transcript levels of rhlR, vqsR, and rpoS The findings of this study demonstrate that RpoN negatively regulates the expression of PQS in nutrient-rich medium and provide evidence that RpoN interacts with pqsA, pqsE, pqsH, and rhlR in response to antibiotic stress.
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45
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Jagmann N, Bleicher V, Busche T, Kalinowski J, Philipp B. The guanidinobutyrase GbuA is essential for the alkylquinolone-regulated pyocyanin production during parasitic growth of Pseudomonas aeruginosa in co-culture with Aeromonas hydrophila. Environ Microbiol 2016; 18:3550-3564. [PMID: 27322205 DOI: 10.1111/1462-2920.13419] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 06/15/2016] [Indexed: 11/30/2022]
Abstract
The opportunistic pathogen Pseudomonas aeruginosa controls the production of virulence factors by quorum sensing (QS). Besides cell density, QS in P. aeruginosa is co-regulated by metabolic influences, especially nutrient limitation. Previously, a co-culture model system was established consisting of P. aeruginosa and the chitinolytic bacterium Aeromonas hydrophila, in which parasitic growth of P. aeruginosa is strictly dependent on the QS-controlled production of pyocyanin in response to nutrient limitation (Jagmann et al., ). In this study, the co-culture was employed to identify novel genes involved in the regulation of pyocyanin production. Via transposon mutagenesis, the gene gbuA encoding a guanidinobutyrase was identified, deletion of which led to a loss of pyocyanin production in co-cultures and to a reduced pyocyanin production in single cultures. Addition of the natural substrate of GbuA to the mutant strain enhanced the negative effect on pyocyanin production in single cultures. The gbuA mutant showed a reduced transcription of the pqsABCDE operon and could be complemented by PqsE overexpression and addition of alkylquinolone signal molecules. The strong effect of gbuA deletion on the QS-controlled pyocyanin production in co-cultures showed the value of this approach for the discovery of novel gene functions linking metabolism and QS in P. aeruginosa.
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Affiliation(s)
- Nina Jagmann
- Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität (WWU) Münster, Corrensstr. 3, Münster, 48149, Germany
| | - Vera Bleicher
- Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität (WWU) Münster, Corrensstr. 3, Münster, 48149, Germany
| | - Tobias Busche
- Center for Biotechnology (CeBiTec), Universität Bielefeld, Universitätsstr. 25, Bielefeld, 33615, Germany
| | - Jörn Kalinowski
- Center for Biotechnology (CeBiTec), Universität Bielefeld, Universitätsstr. 25, Bielefeld, 33615, Germany
| | - Bodo Philipp
- Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität (WWU) Münster, Corrensstr. 3, Münster, 48149, Germany.
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Temperature-responsive in vitro RNA structurome of Yersinia pseudotuberculosis. Proc Natl Acad Sci U S A 2016; 113:7237-42. [PMID: 27298343 DOI: 10.1073/pnas.1523004113] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
RNA structures are fundamentally important for RNA function. Dynamic, condition-dependent structural changes are able to modulate gene expression as shown for riboswitches and RNA thermometers. By parallel analysis of RNA structures, we mapped the RNA structurome of Yersinia pseudotuberculosis at three different temperatures. This human pathogen is exquisitely responsive to host body temperature (37 °C), which induces a major metabolic transition. Our analysis profiles the structure of more than 1,750 RNAs at 25 °C, 37 °C, and 42 °C. Average mRNAs tend to be unstructured around the ribosome binding site. We searched for 5'-UTRs that are folded at low temperature and identified novel thermoresponsive RNA structures from diverse gene categories. The regulatory potential of 16 candidates was validated. In summary, we present a dynamic bacterial RNA structurome and find that the expression of virulence-relevant functions in Y. pseudotuberculosis and reprogramming of its metabolism in response to temperature is associated with a restructuring of numerous mRNAs.
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Gruber JD, Chen W, Parnham S, Beauchesne K, Moeller P, Flume PA, Zhang YM. The role of 2,4-dihydroxyquinoline (DHQ) in Pseudomonas aeruginosa pathogenicity. PeerJ 2016; 4:e1495. [PMID: 26788419 PMCID: PMC4715436 DOI: 10.7717/peerj.1495] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 11/22/2015] [Indexed: 11/20/2022] Open
Abstract
Bacteria synchronize group behaviors using quorum sensing, which is advantageous during an infection to thwart immune cell attack and resist deleterious changes in the environment. In Pseudomonas aeruginosa, the Pseudomonas quinolone signal (Pqs) quorum-sensing system is an important component of an interconnected intercellular communication network. Two alkylquinolones, 2-heptyl-4-quinolone (HHQ) and 2-heptyl-3-hydroxy-4-quinolone (PQS), activate transcriptional regulator PqsR to promote the production of quinolone signals and virulence factors. Our work focused on the most abundant quinolone produced from the Pqs system, 2,4-dihydroxyquinoline (DHQ), which was shown previously to sustain pyocyanin production and antifungal activity of P. aeruginosa. However, little is known about how DHQ affects P. aeruginosa pathogenicity. Using C. elegans as a model for P. aeruginosa infection, we found pqs mutants only able to produce DHQ maintained virulence towards the nematodes similar to wild-type. In addition, DHQ-only producing mutants displayed increased colonization of C. elegans and virulence factor production compared to a quinolone-null strain. DHQ also bound to PqsR and activated the transcription of pqs operon. More importantly, high extracellular concentration of DHQ was maintained in both aerobic and anaerobic growth. High levels of DHQ were also detected in the sputum samples of cystic fibrosis patients. Taken together, our findings suggest DHQ may play an important role in sustaining P. aeruginosa pathogenicity under oxygen-limiting conditions.
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Affiliation(s)
- Jordon D Gruber
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina , Charleston, SC , United States
| | - Wei Chen
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina , Charleston, SC , United States
| | - Stuart Parnham
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina , Charleston, SC , United States
| | - Kevin Beauchesne
- Natural Products Chemistry, National Ocean Service , Charleston, SC , United States
| | - Peter Moeller
- Natural Products Chemistry, National Ocean Service , Charleston, SC , United States
| | - Patrick A Flume
- Department of Medicine, Medical University of South Carolina , Charleston, SC , United States
| | - Yong-Mei Zhang
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina , Charleston, SC , United States
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48
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Sams T, Baker Y, Hodgkinson J, Gross J, Spring D, Welch M. The Pseudomonas Quinolone Signal (PQS). Isr J Chem 2015. [DOI: 10.1002/ijch.201400128] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Tipton KA, Coleman JP, Pesci EC. Post-transcriptional regulation of gene PA5507 controls Pseudomonas quinolone signal concentration in P. aeruginosa. Mol Microbiol 2015; 96:670-83. [PMID: 25662317 DOI: 10.1111/mmi.12963] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/04/2015] [Indexed: 11/29/2022]
Abstract
Pseudomonas aeruginosa can sense and respond to a myriad of environmental signals and utilizes a system of small molecules to communicate through intercellular signaling. The small molecule 2-heptyl-3-hydroxy-4-quinolone (Pseudomonas Quinolone Signal [PQS]) is one of these signals and its synthesis is important for virulence. Previously, we identified an RpiR-type transcriptional regulator, QapR, that positively affects PQS production by repressing the qapR operon. An in-frame deletion of this regulator caused P. aeruginosa to produce a greatly reduced concentration of PQS. Here, we report that QapR translation is linked to the downstream gene PA5507. We found that introduction of a premature stop codon within qapR eliminates transcriptional autorepression of the qapR operon as expected but has no effect on PQS concentration. This was investigated with a series of lacZ reporter fusions which showed that translation of QapR must terminate at, or close to, the native qapR stop codon in order for translation of PA5507 to occur. Also, it was shown that truncation of the 5' end of the qapR transcript permitted PA5507 translation without translation of QapR. Our findings led us to conclude that PA5507 transcription and translation are both tightly controlled by QapR and this control is important for PQS homeostasis.
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Affiliation(s)
- Kyle A Tipton
- Department of Microbiology and Immunology, The Brody School of Medicine at East Carolina University, 600 Moye Blvd., Greenville, North Carolina, 27834, USA
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Welsh MA, Eibergen NR, Moore JD, Blackwell HE. Small molecule disruption of quorum sensing cross-regulation in pseudomonas aeruginosa causes major and unexpected alterations to virulence phenotypes. J Am Chem Soc 2015; 137:1510-9. [PMID: 25574853 DOI: 10.1021/ja5110798] [Citation(s) in RCA: 121] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The opportunistic pathogen Pseudomonas aeruginosa uses three interwoven quorum-sensing (QS) circuits-Las, Rhl, and Pqs-to regulate the global expression of myriad virulence-associated genes. Interception of these signaling networks with small molecules represents an emerging strategy for the development of anti-infective agents against this bacterium. In the current study, we applied a chemical approach to investigate how the Las-Rhl-Pqs QS hierarchy coordinates key virulence phenotypes in wild-type P. aeruginosa. We screened a focused library of synthetic, non-native N-acyl l-homoserine lactones and identified compounds that can drastically alter production of two important virulence factors: pyocyanin and rhamnolipid. We demonstrate that these molecules act by targeting RhlR in P. aeruginosa, a QS receptor that has seen far less scrutiny to date relative to other circuitry. Unexpectedly, modulation of RhlR activity by a single compound induces inverse regulation of pyocyanin and rhamnolipid, a result that was not predicted using genetic approaches to interrogate QS in P. aeruginosa. Further, we show that certain RhlR agonists strongly repress Pqs signaling, revealing disruption of Rhl-Pqs cross-regulation as a novel mechanism for QS inhibition. These compounds significantly expand the known repertoire of chemical probes available to study RhlR in P. aeruginosa. Moreover, our results suggest that designing chemical agents to disrupt Rhl-Pqs crosstalk could be an effective antivirulence strategy to fight this common pathogen.
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Affiliation(s)
- Michael A Welsh
- Department of Chemistry, University of Wisconsin-Madison , 1101 University Avenue, Madison, Wisconsin 53706, United States
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