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Laborda P, Molin S, Johansen HK, Martínez JL, Hernando-Amado S. Role of bacterial multidrug efflux pumps during infection. World J Microbiol Biotechnol 2024; 40:226. [PMID: 38822187 DOI: 10.1007/s11274-024-04042-7] [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: 04/03/2024] [Accepted: 05/29/2024] [Indexed: 06/02/2024]
Abstract
Multidrug efflux pumps are protein complexes located in the cell envelope that enable bacteria to expel, not only antibiotics, but also a wide array of molecules relevant for infection. Hence, they are important players in microbial pathogenesis. On the one hand, efflux pumps can extrude exogenous compounds, including host-produced antimicrobial molecules. Through this extrusion, pathogens can resist antimicrobial agents and evade host defenses. On the other hand, efflux pumps also have a role in the extrusion of endogenous compounds, such as bacterial intercommunication signaling molecules, virulence factors or metabolites. Therefore, efflux pumps are involved in the modulation of bacterial behavior and virulence, as well as in the maintenance of the bacterial homeostasis under different stresses found within the host. This review delves into the multifaceted roles that efflux pumps have, shedding light on their impact on bacterial virulence and their contribution to bacterial infection. These observations suggest that strategies targeting bacterial efflux pumps could both reinvigorate the efficacy of existing antibiotics and modulate the bacterial pathogenicity to the host. Thus, a comprehensive understanding of bacterial efflux pumps can be pivotal for the development of new effective strategies for the management of infectious diseases.
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Affiliation(s)
- Pablo Laborda
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen, 9301, Denmark.
| | - Søren Molin
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Helle Krogh Johansen
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen, 9301, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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Kristensen R, Andersen JB, Rybtke M, Jansen CU, Fritz BG, Kiilerich RO, Uhd J, Bjarnsholt T, Qvortrup K, Tolker-Nielsen T, Givskov M, Jakobsen TH. Inhibition of Pseudomonas aeruginosa quorum sensing by chemical induction of the MexEF-oprN efflux pump. Antimicrob Agents Chemother 2024; 68:e0138723. [PMID: 38189278 PMCID: PMC10848761 DOI: 10.1128/aac.01387-23] [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: 10/26/2023] [Accepted: 11/17/2023] [Indexed: 01/09/2024] Open
Abstract
The cell-to-cell communication system quorum sensing (QS), used by various pathogenic bacteria to synchronize gene expression and increase host invasion potentials, is studied as a potential target for persistent infection control. To search for novel molecules targeting the QS system in the Gram-negative opportunistic pathogen Pseudomonas aeruginosa, a chemical library consisting of 3,280 small compounds from LifeArc was screened. A series of 10 conjugated phenones that have not previously been reported to target bacteria were identified as inhibitors of QS in P. aeruginosa. Two lead compounds (ethylthio enynone and propylthio enynone) were re-synthesized for verification of activity and further elucidation of the mode of action. The isomeric pure Z-ethylthio enynone was used for RNA sequencing, revealing a strong inhibitor of QS-regulated genes, and the QS-regulated virulence factors rhamnolipid and pyocyanin were significantly decreased by treatment with the compounds. A transposon mutagenesis screen performed in a newly constructed lasB-gfp monitor strain identified the target of Z-ethylthio enynone in P. aeruginosa to be the MexEF-OprN efflux pump, which was further established using defined mex knockout mutants. Our data indicate that the QS inhibitory capabilities of Z-ethylthio enynone were caused by the drainage of intracellular signal molecules as a response to chemical-induced stimulation of the MexEF-oprN efflux pump, thereby inhibiting the autogenerated positive feedback and its enhanced signal-molecule synthesis.
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Affiliation(s)
- Rasmus Kristensen
- Department of Immunology and Microbiology, Costerton Biofilm Center, University of Copenhagen, Copenhagen, Denmark
| | - Jens Bo Andersen
- Department of Immunology and Microbiology, Costerton Biofilm Center, University of Copenhagen, Copenhagen, Denmark
| | - Morten Rybtke
- Department of Immunology and Microbiology, Costerton Biofilm Center, University of Copenhagen, Copenhagen, Denmark
| | | | - Blaine Gabriel Fritz
- Department of Immunology and Microbiology, Costerton Biofilm Center, University of Copenhagen, Copenhagen, Denmark
| | - Rikke Overgaard Kiilerich
- Department of Immunology and Microbiology, Costerton Biofilm Center, University of Copenhagen, Copenhagen, Denmark
| | - Jesper Uhd
- Department of Chemistry, Technical University of Denmark, Lyngby, Denmark
| | - Thomas Bjarnsholt
- Department of Immunology and Microbiology, Costerton Biofilm Center, University of Copenhagen, Copenhagen, Denmark
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen, Denmark
| | - Katrine Qvortrup
- Department of Chemistry, Technical University of Denmark, Lyngby, Denmark
| | - Tim Tolker-Nielsen
- Department of Immunology and Microbiology, Costerton Biofilm Center, University of Copenhagen, Copenhagen, Denmark
| | - Michael Givskov
- Department of Immunology and Microbiology, Costerton Biofilm Center, University of Copenhagen, Copenhagen, Denmark
| | - Tim Holm Jakobsen
- Department of Immunology and Microbiology, Costerton Biofilm Center, University of Copenhagen, Copenhagen, Denmark
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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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4
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Wang Z, Ma R, Chen B, Yu X, Wang X, Zuo X, Liang B, Yang J. A transcription factor-based bacterial biosensor system and its application for on-site detection of explosives. Biosens Bioelectron 2024; 244:115805. [PMID: 37948915 DOI: 10.1016/j.bios.2023.115805] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 10/01/2023] [Accepted: 10/29/2023] [Indexed: 11/12/2023]
Abstract
Detecting unexploded landmines is critical due to the environmental pollution and potential humanitarian risks caused by buried landmines. Therefore, this study focused on developing a biosensor system capable of detecting explosives safely and efficiently. A novel transcription factor-based Escherichia coli biosensor was designed to detect 1,3-dinitrobenzene (1,3-DNB). The MexT transcription factor from Pseudomonas putida (P. putida) was identified as the fundamental sensing element in this biosensor. The study found that MexT positively regulated the transcription of PP_2827 by binding to the bidirectional promoter region between them, and significantly enhanced the expression of downstream genes under the condition of 1,3-DNB. The MexT-based biosensor for 1,3-DNB was developed by adopting different combinations of the mexT gene and promoters. The optimized biosensor demonstrated adequate sensitivity for detecting 0.1 μg/mL of 1,3-DNB in a liquid solution with satisfactory specificity and long-term stability. Subsequently, the MexT-based biosensor was integrated into a detection device to simulate the in-field exploration of explosives. The system exhibited a detection sensitivity of 0.5 mg/kg for 1,3-DNB in the sand, and realized the detection of on-site and large-scale area and the location of buried 1,3-DNB under the soil. The study provided a novel transcription factor-based bacterial biosensor and a complete system (China Earth Eye, CEE) for sensitive detection of 1,3-DNB. The good performance of this biosensor system can facilitate the development of accurate, on-site, and high-efficient exploration of explosives in real extensive minefields. Moreover, this 1,3-DNB biosensor can be complementary to the 2,4-DNT biosensor reported before, demonstrating its potential applications in military situations.
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Affiliation(s)
- Zhaobao Wang
- Energy-rich Compound Production by Photosynthetic Carbon Fixation Research Center, Shandong Key Lab of Applied Mycology, College of Life Sciences, Qingdao Agricultural University, PR China
| | - Ran Ma
- Energy-rich Compound Production by Photosynthetic Carbon Fixation Research Center, Shandong Key Lab of Applied Mycology, College of Life Sciences, Qingdao Agricultural University, PR China
| | - Bingjing Chen
- Energy-rich Compound Production by Photosynthetic Carbon Fixation Research Center, Shandong Key Lab of Applied Mycology, College of Life Sciences, Qingdao Agricultural University, PR China
| | - Xiaotong Yu
- Energy-rich Compound Production by Photosynthetic Carbon Fixation Research Center, Shandong Key Lab of Applied Mycology, College of Life Sciences, Qingdao Agricultural University, PR China
| | - Xue Wang
- Energy-rich Compound Production by Photosynthetic Carbon Fixation Research Center, Shandong Key Lab of Applied Mycology, College of Life Sciences, Qingdao Agricultural University, PR China
| | - Xinyun Zuo
- Energy-rich Compound Production by Photosynthetic Carbon Fixation Research Center, Shandong Key Lab of Applied Mycology, College of Life Sciences, Qingdao Agricultural University, PR China
| | - Bo Liang
- Energy-rich Compound Production by Photosynthetic Carbon Fixation Research Center, Shandong Key Lab of Applied Mycology, College of Life Sciences, Qingdao Agricultural University, PR China.
| | - Jianming Yang
- Energy-rich Compound Production by Photosynthetic Carbon Fixation Research Center, Shandong Key Lab of Applied Mycology, College of Life Sciences, Qingdao Agricultural University, PR China.
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Yamasaki S, Zwama M, Yoneda T, Hayashi-Nishino M, Nishino K. Drug resistance and physiological roles of RND multidrug efflux pumps in Salmonella enterica, Escherichia coli and Pseudomonas aeruginosa. MICROBIOLOGY (READING, ENGLAND) 2023; 169:001322. [PMID: 37319001 PMCID: PMC10333786 DOI: 10.1099/mic.0.001322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 03/18/2023] [Indexed: 06/17/2023]
Abstract
Drug efflux pumps transport antimicrobial agents out of bacteria, thereby reducing the intracellular antimicrobial concentration, which is associated with intrinsic and acquired bacterial resistance to these antimicrobials. As genome analysis has advanced, many drug efflux pump genes have been detected in the genomes of bacterial species. In addition to drug resistance, these pumps are involved in various essential physiological functions, such as bacterial adaptation to hostile environments, toxin and metabolite efflux, biofilm formation and quorum sensing. In Gram-negative bacteria, efflux pumps in the resistance–nodulation–division (RND) superfamily play a clinically important role. In this review, we focus on Gram-negative bacteria, including Salmonella enterica , Escherichia coli and Pseudomonas aeruginosa , and discuss the role of RND efflux pumps in drug resistance and physiological functions.
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Affiliation(s)
- Seiji Yamasaki
- SANKEN (The Institute of Scientific and Industrial Research), Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan
- Institute for Advanced Co-Creation Studies, Osaka University, 1-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Martijn Zwama
- SANKEN (The Institute of Scientific and Industrial Research), Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan
| | - Tomohiro Yoneda
- SANKEN (The Institute of Scientific and Industrial Research), Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Mitsuko Hayashi-Nishino
- SANKEN (The Institute of Scientific and Industrial Research), Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Kunihiko Nishino
- SANKEN (The Institute of Scientific and Industrial Research), Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan
- Center for Infectious Disease Education and Research, 2-8 Yamadaoka, Osaka University, Suita, Osaka 565-0871, Japan
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Genetic and Environmental Investigation of a Novel Phenylamino Acetamide Inhibitor of the Pseudomonas aeruginosa Type III Secretion System. Appl Environ Microbiol 2023; 89:e0175222. [PMID: 36519869 PMCID: PMC9888221 DOI: 10.1128/aem.01752-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Traditional antibiotics target essential cellular components or metabolic pathways conserved in both pathogenic and nonpathogenic bacteria. Unfortunately, long-term antibiotic use often leads to antibiotic resistance and disruption of the overall microbiota. In this work, we identified a phenylamino acetamide compound, named 187R, that strongly inhibited the expression of the type III secretion system (T3SS) encoding genes and the secretion of the T3SS effector proteins in Pseudomonas aeruginosa. T3SS is an important virulence factor, as T3SS-deficient strains of P. aeruginosa are greatly attenuated in virulence. We further showed that 187R had no effect on bacterial growth, implying a reduced selective pressure for the development of resistance. 187R-mediated repression of T3SS was dependent on ExsA, the master regulator of T3SS in P. aeruginosa. The impact of 187R on the host-associated microbial community was also tested using the Arabidopsis thaliana phyllosphere as a model. Both culture-independent (Illumina sequencing) and culture-dependent (Biolog) methods showed that the application of 187R had little impact on the composition and function of microbial community compared to the antibiotic streptomycin. Together, these results suggested that compounds that target virulence factors could serve as an alternative strategy for disease management caused by bacterial pathogens. IMPORTANCE New antimicrobial therapies are urgently needed, since antibiotic resistance in human pathogens has become one of the world's most urgent public health problems. Antivirulence therapy has been considered a promising alternative for the management of infectious diseases, as antivirulence compounds target only the virulence factors instead of the growth of bacteria, and they are therefore unlikely to affect commensal microorganisms. However, the impacts of antivirulence compounds on the host microbiota are not well understood. We report a potent synthetic inhibitor of the P. aeruginosa T3SS, 187R, and its effect on the host microbiota of Arabidopsis. Both culture-independent (Illumina sequencing) and culture-dependent (Biolog) methods showed that the impacts of the antivirulence compound on the composition and function of host microbiota were limited. These results suggest that antivirulence compounds can be a potential alternative method to antibiotics.
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Bové M, Kolpen M, Lichtenberg M, Bjarnsholt T, Coenye T. Adaptation of Pseudomonas aeruginosa biofilms to tobramycin and the quorum sensing inhibitor C-30 during experimental evolution requires multiple genotypic and phenotypic changes. MICROBIOLOGY (READING, ENGLAND) 2023; 169:001278. [PMID: 36748633 PMCID: PMC9993117 DOI: 10.1099/mic.0.001278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
In the present study we evaluated the fitness, antimicrobial susceptibility, metabolic activity, gene expression, in vitro production of virulence factors and in vivo virulence of experimentally evolved Pseudomonas aeruginosa PAO1. These strains were previously evolved in the presence of tobramycin and the quorum sensing inhibitor furanone C-30 (C-30) and carried mutations in mexT and fusA1. Compared to the wild-type (WT), the evolved strains show a different growth rate and different metabolic activity, suggesting they have an altered fitness. mexT mutants were less susceptible to C-30 than WT strains; they also show reduced susceptibility to chloramphenicol and ciprofloxacin, two substrates of the MexEF-OprN efflux pump. fusA1 mutants had a decreased susceptibility to aminoglycoside antibiotics, and an increased susceptibility to chloramphenicol. The decreased antimicrobial susceptibility and decreased susceptibility to C-30 was accompanied by a changed metabolic activity profile during treatment. The expression of mexE was significantly increased in mexT mutants and induced by C-30, suggesting that MexEF-OprN exports C-30 out of the bacterial cell. The in vitro production of virulence factors as well as virulence in two in vivo models of the strains evolved in the presence of C-30 was unchanged compared to the virulence of the WT. Finally, the evolved strains were less susceptible towards tobramycin (alone and combined with C-30) in an in vivo mouse model. In conclusion, this study shows that mutations acquired during experimental evolution of P. aeruginosa biofilms in the presence of tobramycin and C-30, are accompanied by an altered fitness, metabolism, mexE expression and in vitro and in vivo antimicrobial susceptibility.
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Affiliation(s)
- Mona Bové
- Laboratory of Pharmaceutical Microbiology, Ghent University, Ghent, Belgium
| | - Mette Kolpen
- Department of Clinical Microbiology, Rigshospitalet, 2200 Copenhagen N, Denmark
| | - Mads Lichtenberg
- Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Thomas Bjarnsholt
- Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Tom Coenye
- Laboratory of Pharmaceutical Microbiology, Ghent University, Ghent, Belgium.,Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
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Zhou D, Huang G, Xu G, Xiang L, Huang S, Chen X, Zhang Y, Wang D. CRISPRi-Mediated Gene Suppression Reveals Putative Reverse Transcriptase Gene PA0715 to Be a Global Regulator of Pseudomonas aeruginosa. Infect Drug Resist 2022; 15:7577-7599. [PMID: 36579125 PMCID: PMC9792118 DOI: 10.2147/idr.s384980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 11/09/2022] [Indexed: 12/24/2022] Open
Abstract
Purpose Pseudomonas aeruginosa is a common pathogen of infection in burn and trauma patients, and multi-drug resistant P. aeruginosa has become an increasingly important pathogen. Essential genes are key to the development of novel antibiotics. The PA0715 gene is a novel unidentified essential gene that has attracted our interest as a potential antibiotic target. Our study aims to determine the exact role of PA0715 in cell physiology and bacterial pathogenicity, providing important clues for antibiotic development. Patients and Methods The shuttle vector pHERD20T containing an arabinose inducible promoter was used to construct the CRISPRi system. Alterations in cellular physiology and bacterial pathogenicity of P. aeruginosa PAO1 after PA0715 inhibition were characterized. High-throughput RNA-seq was performed to gain more insight into the mechanisms by which PA0715 regulates the vital activity of P. aeruginosa. Results We found that down-regulation of PA0715 significantly reduced PAO1 growth rate, motility and chemotaxis, antibiotic resistance, pyocyanin and biofilm production. In addition, PA0715 inhibition reduced the pathogenicity of PAO1 to the greater galleria mellonella larvae. Transcriptional profiling identified 1757 genes including those related to amino acid, carbohydrate, ketone body and organic salt metabolism, whose expression was directly or indirectly controlled by PA0715. Unexpectedly, genes involved in oxidative phosphorylation also varied with PA0715 levels, and these findings support a hitherto unrecognized critical role for PA0715 in oxidative respiration in P. aeruginosa. Conclusion We identified PA0715 as a global regulator of the metabolic network that is indispensable for the survival and reproduction of P. aeruginosa. Our results provide a basis for future studies of potential antibiotic targets for P. aeruginosa and offer new ideas for P. aeruginosa infection control.
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Affiliation(s)
- Dapeng Zhou
- Department of Burns and Plastic Surgery, Affiliated Hospital of Zunyi Medical University, Zunyi, People’s Republic of China
- The Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine of Zunyi Medical University, Zunyi, People’s Republic of China
| | - Guangtao Huang
- Department of Burns and Plastic Surgery, Affiliated Hospital of Zunyi Medical University, Zunyi, People’s Republic of China
- The Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine of Zunyi Medical University, Zunyi, People’s Republic of China
- Department of Burn and Plastic Surgery, Department of Wound Repair, Shenzhen Institute of Translational Medicine, The First Affiliated Hospital of Shenzhen University, Shenzhen Second People’s Hospital, Shenzhen, People’s Republic of China
- Department of Plastic and Reconstructive Surgery, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, People’s Republic of China
| | - Guangchao Xu
- Department of Burns and Plastic Surgery, Affiliated Hospital of Zunyi Medical University, Zunyi, People’s Republic of China
- The Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine of Zunyi Medical University, Zunyi, People’s Republic of China
| | - Lijuan Xiang
- Department of Clinical Laboratory, Shenzhen Institute of Translational Medicine, The First Affiliated Hospital of Shenzhen University, Shenzhen Second People’s Hospital, Shenzhen, People’s Republic of China
| | - Siyi Huang
- Department of Burns and Plastic Surgery, Affiliated Hospital of Zunyi Medical University, Zunyi, People’s Republic of China
- The Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine of Zunyi Medical University, Zunyi, People’s Republic of China
| | - Xinchong Chen
- Department of Burns and Plastic Surgery, Affiliated Hospital of Zunyi Medical University, Zunyi, People’s Republic of China
- The Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine of Zunyi Medical University, Zunyi, People’s Republic of China
| | - Yixin Zhang
- Department of Plastic and Reconstructive Surgery, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, People’s Republic of China
| | - Dali Wang
- Department of Burns and Plastic Surgery, Affiliated Hospital of Zunyi Medical University, Zunyi, People’s Republic of China
- The Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine of Zunyi Medical University, Zunyi, People’s Republic of China
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Rajput A, Tsunemoto H, Sastry AV, Szubin R, Rychel K, Chauhan SM, Pogliano J, Palsson BO. Advanced transcriptomic analysis reveals the role of efflux pumps and media composition in antibiotic responses of Pseudomonas aeruginosa. Nucleic Acids Res 2022; 50:9675-9688. [PMID: 36095122 PMCID: PMC9508857 DOI: 10.1093/nar/gkac743] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 08/06/2022] [Accepted: 09/06/2022] [Indexed: 11/14/2022] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen and major cause of hospital-acquired infections. The virulence of P. aeruginosa is largely determined by its transcriptional regulatory network (TRN). We used 411 transcription profiles of P. aeruginosa from diverse growth conditions to construct a quantitative TRN by identifying independently modulated sets of genes (called iModulons) and their condition-specific activity levels. The current study focused on the use of iModulons to analyze the biofilm production and antibiotic resistance of P. aeruginosa. Our analysis revealed: (i) 116 iModulons, 81 of which show strong association with known regulators; (ii) novel roles of regulators in modulating antibiotics efflux pumps; (iii) substrate-efflux pump associations; (iv) differential iModulon activity in response to beta-lactam antibiotics in bacteriological and physiological media; (v) differential activation of 'Cell Division' iModulon resulting from exposure to different beta-lactam antibiotics and (vi) a role of the PprB iModulon in the stress-induced transition from planktonic to biofilm lifestyle. In light of these results, the construction of an iModulon-based TRN provides a transcriptional regulatory basis for key aspects of P. aeruginosa infection, such as antibiotic stress responses and biofilm formation. Taken together, our results offer a novel mechanistic understanding of P. aeruginosa virulence.
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Affiliation(s)
- Akanksha Rajput
- Department of Bioengineering, University of California, San Diego, La Jolla, CA, USA
| | - Hannah Tsunemoto
- Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Anand V Sastry
- Department of Bioengineering, University of California, San Diego, La Jolla, CA, USA
| | - Richard Szubin
- Department of Bioengineering, University of California, San Diego, La Jolla, CA, USA
| | - Kevin Rychel
- Department of Bioengineering, University of California, San Diego, La Jolla, CA, USA
| | - Siddharth M Chauhan
- Department of Bioengineering, University of California, San Diego, La Jolla, CA, USA
| | - Joe Pogliano
- Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Bernhard O Palsson
- Department of Bioengineering, University of California, San Diego, La Jolla, CA, USA.,Department of Pediatrics, University of California, San Diego, La Jolla, CA, USA.,Center for Microbiome Innovation, University of California San Diego, La Jolla, CA 92093, USA.,Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet, Building 220, 2800 Kongens, Lyngby, Denmark
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10
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Pseudomonas aeruginosa: pathogenesis, virulence factors, antibiotic resistance, interaction with host, technology advances and emerging therapeutics. Signal Transduct Target Ther 2022; 7:199. [PMID: 35752612 PMCID: PMC9233671 DOI: 10.1038/s41392-022-01056-1] [Citation(s) in RCA: 265] [Impact Index Per Article: 132.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 06/04/2022] [Accepted: 06/08/2022] [Indexed: 02/05/2023] Open
Abstract
Pseudomonas aeruginosa (P. aeruginosa) is a Gram-negative opportunistic pathogen that infects patients with cystic fibrosis, burn wounds, immunodeficiency, chronic obstructive pulmonary disorder (COPD), cancer, and severe infection requiring ventilation, such as COVID-19. P. aeruginosa is also a widely-used model bacterium for all biological areas. In addition to continued, intense efforts in understanding bacterial pathogenesis of P. aeruginosa including virulence factors (LPS, quorum sensing, two-component systems, 6 type secretion systems, outer membrane vesicles (OMVs), CRISPR-Cas and their regulation), rapid progress has been made in further studying host-pathogen interaction, particularly host immune networks involving autophagy, inflammasome, non-coding RNAs, cGAS, etc. Furthermore, numerous technologic advances, such as bioinformatics, metabolomics, scRNA-seq, nanoparticles, drug screening, and phage therapy, have been used to improve our understanding of P. aeruginosa pathogenesis and host defense. Nevertheless, much remains to be uncovered about interactions between P. aeruginosa and host immune responses, including mechanisms of drug resistance by known or unannotated bacterial virulence factors as well as mammalian cell signaling pathways. The widespread use of antibiotics and the slow development of effective antimicrobials present daunting challenges and necessitate new theoretical and practical platforms to screen and develop mechanism-tested novel drugs to treat intractable infections, especially those caused by multi-drug resistance strains. Benefited from has advancing in research tools and technology, dissecting this pathogen's feature has entered into molecular and mechanistic details as well as dynamic and holistic views. Herein, we comprehensively review the progress and discuss the current status of P. aeruginosa biophysical traits, behaviors, virulence factors, invasive regulators, and host defense patterns against its infection, which point out new directions for future investigation and add to the design of novel and/or alternative therapeutics to combat this clinically significant pathogen.
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Zhao H, Clevenger AL, Coburn PS, Callegan MC, Rybenkov V. Condensins are essential for Pseudomonas aeruginosa corneal virulence through their control of lifestyle and virulence programs. Mol Microbiol 2022; 117:937-957. [PMID: 35072315 PMCID: PMC9512581 DOI: 10.1111/mmi.14883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 01/20/2022] [Accepted: 01/20/2022] [Indexed: 12/01/2022]
Abstract
Pseudomonas aeruginosa is a significant opportunistic pathogen responsible for numerous human infections. Its high pathogenicity resides in a diverse array of virulence factors and an ability to adapt to hostile environments. We report that these factors are tied to the activity of condensins, SMC and MksBEF, which primarily function in structural chromosome maintenance. This study revealed that both proteins are required for P. aeruginosa virulence during corneal infection. The reduction in virulence was traced to broad changes in gene expression. Transcriptional signatures of smc and mksB mutants were largely dissimilar and non-additive, with the double mutant displaying a distinct gene expression profile. Affected regulons included those responsible for lifestyle control, primary metabolism, surface adhesion and biofilm growth, iron and sulfur assimilation, and numerous virulence factors, including type 3 and type 6 secretion systems. The in vitro phenotypes of condensin mutants mirrored their transcriptional profiles and included impaired production and secretion of multiple virulence factors, growth deficiencies under nutrient limiting conditions, and altered c-di-GMP signaling. Notably, c-di-GMP mediated some but not all transcriptional responses of the mutants. Thus, condensins are integrated into the control of multiple genetic programs related to epigenetic and virulent behavior of P. aeruginosa.
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Affiliation(s)
- Hang Zhao
- Department of Chemistry and Biochemistry, University of Oklahoma, 101 Stephenson Parkway, Norman, OK, USA
| | - April L Clevenger
- Department of Chemistry and Biochemistry, University of Oklahoma, 101 Stephenson Parkway, Norman, OK, USA
| | - Phillip S Coburn
- Department of Ophthalmology, the University of Oklahoma Health Sciences Center, 608 Stanton L. Young Blvd, Oklahoma City, USA
| | - Michelle C Callegan
- Department of Ophthalmology, the University of Oklahoma Health Sciences Center, 608 Stanton L. Young Blvd, Oklahoma City, USA
| | - Valentin Rybenkov
- Department of Chemistry and Biochemistry, University of Oklahoma, 101 Stephenson Parkway, Norman, OK, USA
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12
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Wang D, Zhang X, Yin L, Liu Q, Yu Z, Xu C, Ma Z, Xia Y, Shi J, Gong Y, Bai F, Cheng Z, Wu W, Lin J, Jin Y. RplI interacts with 5’ UTR of exsA to repress its translation and type III secretion system in Pseudomonas aeruginosa. PLoS Pathog 2022; 18:e1010170. [PMID: 34986198 PMCID: PMC8730436 DOI: 10.1371/journal.ppat.1010170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 12/04/2021] [Indexed: 11/19/2022] Open
Abstract
Pseudomonas aeruginosa is an important opportunistic pathogen capable of causing variety of infections in humans. The type III secretion system (T3SS) is a critical virulence determinant of P. aeruginosa in the host infections. Expression of the T3SS is regulated by ExsA, a master regulator that activates the expression of all known T3SS genes. Expression of the exsA gene is controlled at both transcriptional and posttranscriptional levels. Here, we screened a P. aeruginosa transposon (Tn5) insertional mutant library and found rplI, a gene coding for the ribosomal large subunit protein L9, to be a repressor for the T3SS gene expression. Combining real-time quantitative PCR (qPCR), western blotting and lacZ fusion assays, we show that RplI controls the expression of exsA at the posttranscriptional level. Further genetic experiments demonstrated that RplI mediated control of the exsA translation involves 5’ untranslated region (5’ UTR). A ribosome immunoprecipitation assay and qPCR revealed higher amounts of a 24 nt fragment from exsA mRNA being associated with ribosomes in the ΔrplI mutant. An interaction between RplI and exsA mRNA harboring its 24 nt, but not 12 nt, 5’ UTR was confirmed by RNA Gel Mobility Shift and Microscale Thermophoresis assays. Overall, this study identifies the ribosomal large subunit protein L9 as a novel T3SS repressor that inhibits ExsA translation in P. aeruginosa. Ribosomes provide all living organisms the capacity to synthesize proteins. The production of many ribosomal proteins is often controlled by an autoregulatory feedback mechanism. P. aeruginosa is an opportunistic human pathogen and its type III secretion system (T3SS) is a critical virulence determinant in host infections. In this study, by screening a Tn5 mutant library, we identified rplI, encoding ribosomal large subunit protein L9, as a novel repressor for the T3SS. Further exploring the regulatory mechanism, we found that the RplI protein interacts with the 5’ UTR (5’ untranslated region) of exsA, a gene coding for transcriptional activator of the T3SS. Such an interaction likely blocks ribosome loading on the exsA 5’ UTR, inhibiting the initiation of exsA translation. The significance of this work is in the identification of a novel repressor for the T3SS and elucidation of its molecular mechanism. Furthermore, this work provides evidence for individual ribosomal protein regulating mRNA translation beyond its autogenous feedback control.
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Affiliation(s)
- Dan Wang
- 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, China
| | - Xinxin 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, 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, China
| | - Qi Liu
- 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, China
| | - Zhaoli Yu
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Congjuan Xu
- 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, China
| | - Zhenzhen Ma
- 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, China
| | - Yushan Xia
- 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, China
| | - Jing Shi
- 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, China
| | - Yuehua Gong
- Cancer Institute, the First Affiliated Hospital of China Medical University, Shenyang, 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, 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, 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, China
| | - Jinzhong Lin
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Zhongshan Hospital, Fudan University, Shanghai, 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, China
- * E-mail:
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13
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Reigada I, San-Martin-Galindo P, Gilbert-Girard S, Chiaro J, Cerullo V, Savijoki K, Nyman TA, Fallarero A, Miettinen I. Surfaceome and Exoproteome Dynamics in Dual-Species Pseudomonas aeruginosa and Staphylococcus aureus Biofilms. Front Microbiol 2021; 12:672975. [PMID: 34248881 PMCID: PMC8267900 DOI: 10.3389/fmicb.2021.672975] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 05/21/2021] [Indexed: 01/12/2023] Open
Abstract
Bacterial biofilms are an important underlying cause for chronic infections. By switching into the biofilm state, bacteria can evade host defenses and withstand antibiotic chemotherapy. Despite the fact that biofilms at clinical and environmental settings are mostly composed of multiple microbial species, biofilm research has largely been focused on single-species biofilms. In this study, we investigated the interaction between two clinically relevant bacterial pathogens (Staphylococcus aureus and Pseudomonas aeruginosa) by label-free quantitative proteomics focusing on proteins associated with the bacterial cell surfaces (surfaceome) and proteins exported/released to the extracellular space (exoproteome). The changes observed in the surfaceome and exoproteome of P. aeruginosa pointed toward higher motility and lower pigment production when co-cultured with S. aureus. In S. aureus, lower abundances of proteins related to cell wall biosynthesis and cell division, suggesting increased persistence, were observed in the dual-species biofilm. Complementary phenotypic analyses confirmed the higher motility and the lower pigment production in P. aeruginosa when co-cultured with S. aureus. Higher antimicrobial tolerance associated with the co-culture setting was additionally observed in both species. To the best of our knowledge, this study is among the first systematic explorations providing insights into the dynamics of both the surfaceome and exoproteome of S. aureus and P. aeruginosa dual-species biofilms.
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Affiliation(s)
- Inés Reigada
- Drug Research Program, Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland
| | - Paola San-Martin-Galindo
- Drug Research Program, Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland
| | - Shella Gilbert-Girard
- Drug Research Program, Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland
| | - Jacopo Chiaro
- Drug Research Program, Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland
| | - Vincenzo Cerullo
- Drug Research Program, Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland
| | - Kirsi Savijoki
- Drug Research Program, Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland
| | - Tuula A Nyman
- Department of Immunology, Institute of Clinical Medicine, Rikshospitalet, University of Oslo, Oslo, Norway
| | - Adyary Fallarero
- Drug Research Program, Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland
| | - Ilkka Miettinen
- Drug Research Program, Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland
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14
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Reales-Calderón JA, Sun Z, Mascaraque V, Pérez-Navarro E, Vialás V, Deutsch EW, Moritz RL, Gil C, Martínez JL, Molero G. A wide-ranging Pseudomonas aeruginosa PeptideAtlas build: A useful proteomic resource for a versatile pathogen. J Proteomics 2021; 239:104192. [PMID: 33757883 PMCID: PMC8668395 DOI: 10.1016/j.jprot.2021.104192] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 02/17/2021] [Accepted: 03/10/2021] [Indexed: 01/05/2023]
Abstract
Pseudomonas aeruginosa is an important opportunistic human pathogen with high prevalence in nosocomial infections. This microorganism is a good model for understanding biological processes such as the quorum-sensing response, the metabolic integration of virulence, the mechanisms of global regulation of bacterial physiology, and the evolution of antibiotic resistance. Till now, P. aeruginosa proteomic data, although available in several on-line repositories, were dispersed and difficult to access. In the present work, proteomes of the PAO1 strain grown under different conditions and from diverse cellular compartments have been joined to build the Pseudomonas PeptideAtlas. This resource is a comprehensive mass spectrometry-derived peptide and inferred protein database with 71.3% coverage of the total predicted proteome of P. aeruginosa PAO1, the highest coverage among bacterial PeptideAtlas datasets. The proteins included cover 89% of metabolic proteins, 72% of proteins involved in genetic information processing, 83% of proteins responsible for environmental information processing, more than 88% of the ones related to quorum sensing and biofilm formation, and 89% of proteins responsible for antimicrobial resistance. It exemplifies a necessary tool for targeted proteomics studies, system-wide observations, and cross-species observational studies. The manuscript describes the building of the PeptideAtlas and the contribution of the different proteomic data used. SIGNIFICANCE: Pseudomonas aeruginosa is among the most versatile human bacterial pathogens. Studies of its proteome are very important as they can reveal virulence factors and mechanisms of antibiotic resistance. The construction of a proteomic resource such as the PeptideAtlas enables targeted proteomics studies, system-wide observations, and cross-species observational studies.
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Affiliation(s)
- J A Reales-Calderón
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid, Spain
| | - Z Sun
- Institute for Systems Biology, Seattle, WA, USA
| | - V Mascaraque
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid, Spain
| | - E Pérez-Navarro
- Unidad de Proteómica de la Universidad Complutense de Madrid, Spain
| | - V Vialás
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid, Spain
| | - E W Deutsch
- Institute for Systems Biology, Seattle, WA, USA
| | - R L Moritz
- Institute for Systems Biology, Seattle, WA, USA
| | - C Gil
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid, Spain; Unidad de Proteómica de la Universidad Complutense de Madrid, Spain
| | - J L Martínez
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, CSIC, Madrid, Spain
| | - G Molero
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid, Spain.
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15
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Wang T, Sun W, Fan L, Hua C, Wu N, Fan S, Zhang J, Deng X, Yan J. An atlas of the binding specificities of transcription factors in Pseudomonas aeruginosa directs prediction of novel regulators in virulence. eLife 2021; 10:61885. [PMID: 33779544 PMCID: PMC8041468 DOI: 10.7554/elife.61885] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 03/26/2021] [Indexed: 12/14/2022] Open
Abstract
A high-throughput systematic evolution of ligands by exponential enrichment assay was applied to 371 putative TFs in Pseudomonas aeruginosa, which resulted in the robust enrichment of 199 unique sequence motifs describing the binding specificities of 182 TFs. By scanning the genome, we predicted in total 33,709 significant interactions between TFs and their target loci, which were more than 11-fold enriched in the intergenic regions but depleted in the gene body regions. To further explore and delineate the physiological and pathogenic roles of TFs in P. aeruginosa, we constructed regulatory networks for nine major virulence-associated pathways and found that 51 TFs were potentially significantly associated with these virulence pathways, 32 of which had not been characterized before, and some were even involved in multiple pathways. These results will significantly facilitate future studies on transcriptional regulation in P. aeruginosa and other relevant pathogens, and accelerate to discover effective treatment and prevention strategies for the associated infectious diseases.
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Affiliation(s)
- Tingting Wang
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China
| | - Wenju Sun
- School of Medicine, Northwest University, Xi'an, China
| | - Ligang Fan
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China.,School of Medicine, Northwest University, Xi'an, China
| | - Canfeng Hua
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China
| | - Nan Wu
- School of Medicine, Northwest University, Xi'an, China
| | - Shaorong Fan
- School of Medicine, Northwest University, Xi'an, China
| | - Jilin Zhang
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Solna, Sweden
| | - Xin Deng
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China
| | - Jian Yan
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China.,School of Medicine, Northwest University, Xi'an, China
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16
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The Small RNAs PA2952.1 and PrrH as Regulators of Virulence, Motility, and Iron Metabolism in Pseudomonas aeruginosa. Appl Environ Microbiol 2021; 87:AEM.02182-20. [PMID: 33158897 DOI: 10.1128/aem.02182-20] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Accepted: 11/03/2020] [Indexed: 02/06/2023] Open
Abstract
Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen that undergoes swarming motility in response to semisolid conditions with amino acids as a nitrogen source. With a genome encoding hundreds of potential intergenic small RNAs (sRNAs), P. aeruginosa can easily adapt to different conditions and stresses. We previously identified 20 sRNAs that were differentially expressed (DE) under swarming conditions. Here, these sRNAs were overexpressed in strain PAO1 and were subjected to an array of phenotypic screens. Overexpression of the PrrH sRNA resulted in decreased swimming motility, whereas a ΔprrH mutant had decreased cytotoxicity and increased pyoverdine production. Overexpression of the previously uncharacterized PA2952.1 sRNA resulted in decreased swarming and swimming motilities, increased gentamicin and tobramycin resistance under swarming conditions, and increased trimethoprim susceptibility. Transcriptome sequencing (RNA-Seq) and proteomic analysis were performed on the wild type (WT) overexpressing PA2952.1 compared to the empty vector control under swarming conditions, and these revealed the differential expression (absolute fold change [FC] ≥ 1.5) of 784 genes and the differential abundance (absolute FC ≥ 1.25) of 59 proteins. Among these were found 73 transcriptional regulators, two-component systems, and sigma and anti-sigma factors. Downstream effectors included downregulated pilus and flagellar genes, the upregulated efflux pump MexGHI-OpmD, and the upregulated arn operon. Genes involved in iron and zinc uptake were generally upregulated, and certain pyoverdine genes were upregulated. Overall, the sRNAs PA2952.1 and PrrH appeared to be involved in regulating virulence-related programs in P. aeruginosa, including iron acquisition and motility.IMPORTANCE Due to the rising incidence of multidrug-resistant (MDR) strains and the difficulty of eliminating P. aeruginosa infections, it is important to understand the regulatory mechanisms that allow this bacterium to adapt to and thrive under a variety of conditions. Small RNAs (sRNAs) are one regulatory mechanism that allows bacteria to change the amount of protein synthesized. In this study, we overexpressed 20 different sRNAs in order to investigate how this might affect different bacterial behaviors. We found that one of the sRNAs, PrrH, played a role in swimming motility and virulence phenotypes, indicating a potentially important role in clinical infections. Another sRNA, PA2952.1, affected other clinically relevant phenotypes, including motility and antibiotic resistance. RNA-Seq and proteomics of the strain overexpressing PA2952.1 revealed the differential expression of 784 genes and 59 proteins, with a total of 73 regulatory factors. This substantial dysregulation indicates an important role for the sRNA PA2952.1.
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17
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Xu C, Liu H, Pan X, Ma Z, Wang D, Zhang X, Zhu G, Bai F, Cheng Z, Wu W, Jin Y. Mechanisms for Development of Ciprofloxacin Resistance in a Clinical Isolate of Pseudomonas aeruginosa. Front Microbiol 2021; 11:598291. [PMID: 33488544 PMCID: PMC7819972 DOI: 10.3389/fmicb.2020.598291] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 11/24/2020] [Indexed: 12/21/2022] Open
Abstract
Treatment of infections by Pseudomonas aeruginosa is difficult due to its high intrinsic and acquired antibiotic resistance. Upon colonization in the human hosts, P. aeruginosa accumulates genetic mutations that confer the bacterium antibiotic resistance and ability to better live in the host environment. Characterizing the evolutionary traits would provide important insights into the development of effective combinatory antibiotic therapies to cure P. aeruginosa infections. In this work, we performed a detailed analysis of the molecular mechanisms by which a clinical isolate (CSP18) yields a ciprofloxacin-resistant derivative (CRP42). Genomic DNA re-sequencing and RNAseq were carried out to compare the genomic mutational signature and transcriptional profiles between the two isolates. The results indicated that D87G mutation in GyrA, together with MexEF-OprN hyper-expression caused by F7S mutation in MexS, was responsible for the increased resistance to ciprofloxacin in the isolate CRP42. Further simulation of CRP42 by gene editing in CSP18 demonstrated that D87G mutation in GyrA rendered CSP18 a fourfold increase in minimum inhibitory concentration against ciprofloxacin, while F7S mutation in MexS conferred an additional eightfold increase. Our experimental results demonstrate for the first time that the clinically relevant F7S point mutation in MexS results in hyper-expression of the mexEF-oprN and thus confers P. aeruginosa resistance to ciprofloxacin.
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Affiliation(s)
- Congjuan Xu
- 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, China
| | - Huimin Liu
- Tianjin Union Medical Center, Nankai University Affiliated Hospital, Tianjin, China
| | - 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, China
| | - Zhenzhen Ma
- 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, China
| | - Dan Wang
- 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, China
| | - Xinxin 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, China
| | - Guangbo Zhu
- Tianjin Union Medical Center, Nankai University Affiliated Hospital, Tianjin, 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, 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, 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, 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, China
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18
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Henriquez T, Baldow T, Lo YK, Weydert D, Brachmann A, Jung H. Involvement of MexS and MexEF-OprN in Resistance to Toxic Ion Chelators in Pseudomonas putida KT2440. Microorganisms 2020; 8:microorganisms8111782. [PMID: 33202537 PMCID: PMC7697342 DOI: 10.3390/microorganisms8111782] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 11/09/2020] [Accepted: 11/12/2020] [Indexed: 01/22/2023] Open
Abstract
Bacteria must be able to cope with harsh environments to survive. In Gram-negative bacteria like Pseudomonas species, resistance-nodulation-division (RND) transporters contribute to this task by pumping toxic compounds out of cells. Previously, we found that the RND system TtgABC of Pseudomonas putida KT2440 confers resistance to toxic metal chelators of the bipyridyl group. Here, we report that the incubation of a ttgB mutant in medium containing 2,2’-bipyridyl generated revertant strains able to grow in the presence of this compound. This trait was related to alterations in the pp_2827 locus (homolog of mexS in Pseudomonas aeruginosa). The deletion and complementation of pp_2827 confirmed the importance of the locus for the revertant phenotype. Furthermore, alteration in the pp_2827 locus stimulated expression of the mexEF-oprN operon encoding an RND efflux pump. Deletion and complementation of mexF confirmed that the latter system can compensate the growth defect of the ttgB mutant in the presence of 2,2’-bipyridyl. To our knowledge, this is the first report on a role of pp_2827 (mexS) in the regulation of mexEF-oprN in P. putida KT2440. The results expand the information about the significance of MexEF-OprN in the stress response of P. putida KT2440 and the mechanisms for coping with bipyridyl toxicity.
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Affiliation(s)
- Tania Henriquez
- Biozentrum, Mikrobiologie, Ludwig-Maximilians-Universität München, 82152 Martinsried, Germany; (T.H.); (T.B.); (Y.K.L.); (D.W.)
| | - Tom Baldow
- Biozentrum, Mikrobiologie, Ludwig-Maximilians-Universität München, 82152 Martinsried, Germany; (T.H.); (T.B.); (Y.K.L.); (D.W.)
| | - Yat Kei Lo
- Biozentrum, Mikrobiologie, Ludwig-Maximilians-Universität München, 82152 Martinsried, Germany; (T.H.); (T.B.); (Y.K.L.); (D.W.)
| | - Dina Weydert
- Biozentrum, Mikrobiologie, Ludwig-Maximilians-Universität München, 82152 Martinsried, Germany; (T.H.); (T.B.); (Y.K.L.); (D.W.)
| | - Andreas Brachmann
- Biozentrum, Genetik, Ludwig-Maximilians-Universität München, 82152 Martinsried, Germany;
| | - Heinrich Jung
- Biozentrum, Mikrobiologie, Ludwig-Maximilians-Universität München, 82152 Martinsried, Germany; (T.H.); (T.B.); (Y.K.L.); (D.W.)
- Correspondence:
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19
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Xiang L, Qi F, Jiang L, Tan J, Deng C, Wei Z, Jin S, Huang G. CRISPR-dCas9-mediated knockdown of prtR, an essential gene in Pseudomonas aeruginosa. Lett Appl Microbiol 2020; 71:386-393. [PMID: 32506497 DOI: 10.1111/lam.13337] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Revised: 05/19/2020] [Accepted: 05/27/2020] [Indexed: 12/21/2022]
Abstract
Pseudomonas aeruginosa is a widely distributed non-fermentative Gram-negative opportunistic pathogen that is often responsible for nosocomial infections. Gene interference is a potentially valuable tool for investigating essential genes in P. aeruginosa. To establish a gene interference platform in P. aeruginosa, CRISPR system was used with an inactive Cas9 protein. The CRISPR-dCas9 system was cloned into pHERD20T, a shuttle vector with arabinose inducible promoter, and was further modified to target a regulatory gene prtR that is essential for the viability of P. aeruginosa. Cells expressing the prtR-targeting CRISPR interference (CRISPRi) showed growth defect in an arabinose dose-dependent manner. A high-throughput RNA sequencing analysis of bacterial cells with or without the CRISPRi-mediated prtR inhibition indicated that prtRis a global regulator affecting multiple biological processes. In conclusion, the CRISPR-dCas9-based gene knockdown system has been successfully implemented in P. aeruginosa and demonstrated to be an effective tool in the investigation of essential or difficult-to-inactivate genes in this species.
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Affiliation(s)
- L Xiang
- Department of Laboratory Medicine, Affiliated Hospital of Zunyi Medical University, Zunyi, China
| | - F Qi
- Department of Plastic and Burn Surgery, The Affiliated Hospital of Zunyi Medical University, Zunyi, China
| | - L Jiang
- Department of Plastic and Burn Surgery, The Affiliated Hospital of Zunyi Medical University, Zunyi, China
| | - J Tan
- Department of Plastic and Burn Surgery, The Affiliated Hospital of Zunyi Medical University, Zunyi, China
| | - C Deng
- Department of Plastic and Burn Surgery, The Affiliated Hospital of Zunyi Medical University, Zunyi, China
| | - Z Wei
- Department of Plastic and Burn Surgery, The Affiliated Hospital of Zunyi Medical University, Zunyi, China
| | - S Jin
- Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - G Huang
- Department of Plastic and Burn Surgery, The Affiliated Hospital of Zunyi Medical University, Zunyi, China
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Karna SLR, Nguyen JQ, Evani SJ, Qian LW, Chen P, Abercrombie JJ, Sebastian EA, Fourcaudot AB, Leung KP. T3SS and alginate biosynthesis of Pseudomonas aeruginosa impair healing of infected rabbit wounds. Microb Pathog 2020; 147:104254. [PMID: 32416139 DOI: 10.1016/j.micpath.2020.104254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 05/05/2020] [Accepted: 05/08/2020] [Indexed: 10/24/2022]
Abstract
Pseudomonas aeruginosa (a Gram-negative bacterium) is an opportunistic pathogen found in many infected wounds and is known to impair healing. To test the hypothesis that knocking out P. aeruginosa genes that are overexpressed during wound infection can cripple a pathogen's ability to impair healing, we assessed two pathways: the Type III secretion system (T3SS) and alginate biosynthesis. We generated single- and double-mutant strains of ExsA (T3SS activator), AlgD (GDP- mannose 6-dehydrogenase of alginate biosynthesis) and their complemented strains and evaluated their pathogenicity in a rabbit ear full-thickness excision-wound infection model. Wounds were inoculated with different strains (wild type, mutants, and complementary strains) at 106 CFU/wound on post-wounding day 3. After 24 h, 5 days and 9 days post-infection, wounds were harvested for measuring bacterial counts (viable and total) and wound healing (epithelial gap). On day 9 post-infection, the viable counts of the double mutant, (exsA/algD)‾ were 100-fold lower than the counts of the wild type (PAO1), single mutants, or the complement double-mutant, (exsA/algD)‾/+. Also, when compared to wounds infected with wild type or control strains, wounds infected with the double-knockout mutant was less inhibitory to wound healing (p < 0.05). Additionally, the double mutant showed greater susceptibility to macrophage phagocytosis in vitro than all other strains (p < 0.001). In conclusion, compared to single gene knockouts, double knockout of virulence genes in T3SS pathway and alginate biosynthesis pathway is more effective in reducing P. aeruginosa pathogenicity and its ability to impair wound healing. This study highlights the necessity of a dual-targeted anti-virulence strategy to improve healing outcomes of P. aeruginosa-infected wounds.
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Affiliation(s)
- S L Rajasekhar Karna
- Division of Combat Wound Repair, US Army Institute of Surgical Research, JBSA Fort Sam Houston, TX, USA
| | - Jesse Q Nguyen
- Division of Combat Wound Repair, US Army Institute of Surgical Research, JBSA Fort Sam Houston, TX, USA
| | - Shankar Jaikishan Evani
- Division of Combat Wound Repair, US Army Institute of Surgical Research, JBSA Fort Sam Houston, TX, USA
| | - Li-Wu Qian
- Division of Combat Wound Repair, US Army Institute of Surgical Research, JBSA Fort Sam Houston, TX, USA
| | - Ping Chen
- Division of Combat Wound Repair, US Army Institute of Surgical Research, JBSA Fort Sam Houston, TX, USA
| | - Johnathan J Abercrombie
- Division of Combat Wound Repair, US Army Institute of Surgical Research, JBSA Fort Sam Houston, TX, USA
| | - Eliza A Sebastian
- Division of Combat Wound Repair, US Army Institute of Surgical Research, JBSA Fort Sam Houston, TX, USA
| | - Andrea B Fourcaudot
- Division of Combat Wound Repair, US Army Institute of Surgical Research, JBSA Fort Sam Houston, TX, USA
| | - Kai P Leung
- Division of Combat Wound Repair, US Army Institute of Surgical Research, JBSA Fort Sam Houston, TX, USA.
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21
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Foppa C, Ng SC, Montorsi M, Spinelli A. Anastomotic leak in colorectal cancer patients: New insights and perspectives. Eur J Surg Oncol 2020; 46:943-954. [PMID: 32139117 DOI: 10.1016/j.ejso.2020.02.027] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2019] [Revised: 02/09/2020] [Accepted: 02/20/2020] [Indexed: 12/14/2022] Open
Abstract
Anastomotic leak (AL) remains a potentially life-threatening sequela of colorectal surgery impacting on mortality, short- and long-term morbidity, quality of life, local recurrence (LR) and disease-free survival. Despite technical improvements and the identification of several surgery- and patient-related factors associated to the risk of AL, its incidence has not significantly changed over time. In this context, the clarification of the mechanisms underlying anastomotic healing remains an important unmet need, crucial for improving patients' outcomes. This review concentrates on novel key findings in the etiopathogenesis of AL, how they can contribute in determining LR, and measures which may contribute to reducing its incidence. AL results from a complex, dynamic interplay of several factors and biological processes, including host genetics, gut microbiome, inflammation and the immune system. Many of these factors seem to act in concert to drive both AL and LR, even if the exact mechanisms remain to be elucidated. The next generation sequencing technology, including the microbial metagenomics, could lead to tailored bowel preparations targeting only those pathogens that can cause AL. Significant progress is being made in each of the reviewed areas, moving toward translational and targeted therapeutic strategies to prevent the difficult complication of AL.
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Affiliation(s)
- Caterina Foppa
- Division of Colon and Rectal Surgery, Humanitas Clinical and Research Hospital, Rozzano, Milan, Italy.
| | - Siew Chien Ng
- Department of Medicine and Therapeutics, Division of Gastroenterology and Hepatology, State Key Laboratory of Digestive Disease, The Chinese University of Hong Kong, Prince of Wales Hospital, Hong Kong, China.
| | - Marco Montorsi
- Division of General and Digestive Surgery, Humanitas Clinical and Research Hospital, Rozzano, Milan, Italy; Department of Biomedical Sciences, Humanitas University, Rozzano, Milan, Italy.
| | - Antonino Spinelli
- Humanitas Clinical and Research Center - IRCCS -, via Manzoni 56, 20089 Rozzano (Mi) - Italy; Humanitas University, Department of Biomedical Sciences, Via Rita Levi Montalcini 4, 20090 Pieve Emanuele - Milan, Italy.
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22
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Kim S, Kim SH, Ahn J, Jo I, Lee ZW, Choi SH, Ha NC. Crystal Structure of the Regulatory Domain of MexT, a Transcriptional Activator of the MexEFOprN Efflux Pump in Pseudomonas aeruginosa. Mol Cells 2019; 42:850-857. [PMID: 31722511 PMCID: PMC6939650 DOI: 10.14348/molcells.2019.0168] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 09/06/2019] [Accepted: 10/07/2019] [Indexed: 12/02/2022] Open
Abstract
The Gram-negative opportunistic pathogen, Pseudomonas aeruginosa , has multiple multidrug efflux pumps. MexT, a LysR-type transcriptional regulator, functions as a transcriptional activator of the MexEF-OprN efflux system. MexT consists of an N-terminal DNA-binding domain and a C-terminal regulatory domain (RD). Little is known regarding MexT ligands and its mechanism of activation. We elucidated the crystal structure of the MexT RD at 2.0 Å resolution. The structure comprised two protomer chains in a dimeric arrangement. MexT possessed an arginine-rich region and a hydrophobic patch lined by a variable loop, both of which are putative ligand-binding sites. The three-dimensional structure of MexT provided clues to the interacting ligand structure. A DNase I footprinting assay of full-length MexT identified two MexT-binding sequence in the mexEF oprN promoter. Our findings enhance the understanding of the regulation of MexT-dependent activation of efflux pumps.
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Affiliation(s)
- Suhyeon Kim
- Department of Agricultural Biotechnology, Center for Food Safety and Toxicology, Center for Food and Bioconvergence, and Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul 08826,
Korea
| | - Songhee H. Kim
- Institute of Molecular Biology and Genetics, Seoul National University, Seoul 08826,
Korea
| | - Jinsook Ahn
- Department of Agricultural Biotechnology, Center for Food Safety and Toxicology, Center for Food and Bioconvergence, and Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul 08826,
Korea
| | - Inseong Jo
- Department of Agricultural Biotechnology, Center for Food Safety and Toxicology, Center for Food and Bioconvergence, and Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul 08826,
Korea
| | - Zee-Won Lee
- Department of Agricultural Biotechnology, Center for Food Safety and Toxicology, Center for Food and Bioconvergence, and Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul 08826,
Korea
| | - Sang Ho Choi
- Department of Agricultural Biotechnology, Center for Food Safety and Toxicology, Center for Food and Bioconvergence, and Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul 08826,
Korea
| | - Nam-Chul Ha
- Department of Agricultural Biotechnology, Center for Food Safety and Toxicology, Center for Food and Bioconvergence, and Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul 08826,
Korea
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23
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LoVullo ED, Schweizer HP. Pseudomonas aeruginosa mexT is an indicator of PAO1 strain integrity. J Med Microbiol 2019; 69:139-145. [PMID: 31859619 DOI: 10.1099/jmm.0.001128] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Laboratory research with Pseudomonas aeruginosa commonly involves the prototype strain PAO1. There is continued concern that PAO1 sublines maintained and propagated in the same laboratory or different laboratories exhibit genetic and phenotypic variability that may affect the reproducibility and validity of research. Whole-genome sequencing and other research identified the mexT locus as a mutational hotspot, but the explication of the diverse mutations present in the various sublines and consequences remained rather cursory. Here we present evidence that MexT sequence diversity is a predictor of PAO1 lineage integrity and define the protein's prototype sequence.
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Affiliation(s)
- Eric D LoVullo
- Department of Molecular Genetics and Microbiology, College of Medicine, Emerging Pathogens Institute, 2055 Mowry Road, Gainesville, FL 32610, USA
| | - Herbert P Schweizer
- Department of Molecular Genetics and Microbiology, College of Medicine, Emerging Pathogens Institute, 2055 Mowry Road, Gainesville, FL 32610, USA
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24
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Hill IT, Tallo T, Dorman MJ, Dove SL. Loss of RNA Chaperone Hfq Unveils a Toxic Pathway in Pseudomonas aeruginosa. J Bacteriol 2019; 201:e00232-19. [PMID: 31358608 PMCID: PMC6755729 DOI: 10.1128/jb.00232-19] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 07/22/2019] [Indexed: 12/17/2022] Open
Abstract
Hfq is an RNA chaperone that serves as a master regulator of bacterial physiology. Here we show that in the opportunistic pathogen Pseudomonas aeruginosa, the loss of Hfq can result in a dramatic reduction in growth in a manner that is dependent upon MexT, a transcription regulator that governs antibiotic resistance in this organism. Using a combination of chromatin immunoprecipitation with high-throughput sequencing and transposon insertion sequencing, we identify the MexT-activated genes responsible for mediating the growth defect of hfq mutant cells. These include a newly identified MexT-controlled gene that we call hilR We demonstrate that hilR encodes a small protein that is acutely toxic to wild-type cells when produced ectopically. Furthermore, we show that hilR expression is negatively regulated by Hfq, offering a possible explanation for the growth defect of hfq mutant cells. Finally, we present evidence that the expression of MexT-activated genes is dependent upon GshA, an enzyme involved in the synthesis of glutathione. Our findings suggest that Hfq can influence the growth of P. aeruginosa by limiting the toxic effects of specific MexT-regulated genes. Moreover, our results identify glutathione to be a factor important for the in vivo activity of MexT.IMPORTANCE Here we show that the conserved RNA chaperone Hfq is important for the growth of the opportunistic pathogen Pseudomonas aeruginosa We found that the growth defect of hfq mutant cells is dependent upon the expression of genes that are under the control of the transcription regulator MexT. These include a gene that we refer to as hilR, which we show is negatively regulated by Hfq and encodes a small protein that can be toxic when ectopically produced in wild-type cells. Thus, Hfq can influence the growth of P. aeruginosa by limiting the toxic effects of MexT-regulated genes, including one encoding a previously unrecognized small protein. We also show that MexT activity depends on an enzyme that synthesizes glutathione.
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Affiliation(s)
- Ian T Hill
- Division of Infectious Diseases, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Thomas Tallo
- Division of Infectious Diseases, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Matthew J Dorman
- Division of Infectious Diseases, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Simon L Dove
- Division of Infectious Diseases, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
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25
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An integrated genomic regulatory network of virulence-related transcriptional factors in Pseudomonas aeruginosa. Nat Commun 2019; 10:2931. [PMID: 31270321 PMCID: PMC6610081 DOI: 10.1038/s41467-019-10778-w] [Citation(s) in RCA: 84] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Accepted: 05/30/2019] [Indexed: 01/12/2023] Open
Abstract
The virulence of Pseudomonas aeruginosa, a Gram-negative opportunistic pathogen, is regulated by many transcriptional factors (TFs) that control the expression of quorum sensing and protein secretion systems. Here, we report a genome-wide, network-based approach to dissect the crosstalk between 20 key virulence-related TFs. Using chromatin immunoprecipitation coupled with high-throughput sequencing (ChIP-seq), as well as RNA-seq, we identify 1200 TF-bound genes and 4775 differentially expressed genes. We experimentally validate 347 of these genes as functional target genes, and describe the regulatory relationships of the 20 TFs with their targets in a network that we call ‘Pseudomonas aeruginosa genomic regulatory network’ (PAGnet). Analysis of the network led to the identification of novel functions for two TFs (ExsA and GacA) in quorum sensing and nitrogen metabolism. Furthermore, we present an online platform and R package based on PAGnet to facilitate updating and user-customised analyses. The virulence of Pseudomonas aeruginosa is regulated by many transcriptional factors (TFs). Here, the authors study the crosstalk between 20 key virulence-related TFs, validate 347 functional target genes, and describe the regulatory relationships of the 20 TFs with their targets in a network that is available as an online platform.
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26
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Fitting Pieces into the Puzzle of Pseudomonas aeruginosa Type III Secretion System Gene Expression. J Bacteriol 2019; 201:JB.00209-19. [PMID: 31010903 DOI: 10.1128/jb.00209-19] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Type III secretion systems (T3SS) are widely distributed in Gram-negative microorganisms and critical for host-pathogen and host-symbiont interactions with plants and animals. Central features of the T3SS are a highly conserved set of secretion and translocation genes and contact dependence wherein host-pathogen interactions trigger effector protein delivery and serve as an inducing signal for T3SS gene expression. In addition to these conserved features, there are pathogen-specific properties that include a unique repertoire of effector genes and mechanisms to control T3SS gene expression. The Pseudomonas aeruginosa T3SS serves as a model system to understand transcriptional and posttranscriptional mechanisms involved in the control of T3SS gene expression. The central regulatory feature is a partner-switching system that controls the DNA-binding activity of ExsA, the primary regulator of T3SS gene expression. Superimposed upon the partner-switching mechanism are cyclic AMP and cyclic di-GMP signaling systems, two-component systems, global regulators, and RNA-binding proteins that have positive and negative effects on ExsA transcription and/or synthesis. In the present review, we discuss advances in our understanding of how these regulatory systems orchestrate the activation of T3SS gene expression in the context of acute infections and repression of the T3SS as P. aeruginosa adapts to and colonizes the cystic fibrosis airways.
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27
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Jin Y, Zhang M, Zhu F, Peng Q, Weng Y, Zhao Q, Liu C, Bai F, Cheng Z, Jin S, Wu W. NrtR Regulates the Type III Secretion System Through cAMP/Vfr Pathway in Pseudomonas aeruginosa. Front Microbiol 2019; 10:85. [PMID: 30761117 PMCID: PMC6363681 DOI: 10.3389/fmicb.2019.00085] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 01/16/2019] [Indexed: 11/23/2022] Open
Abstract
The type III secretion system (T3SS) plays an important role in the pathogenesis of Pseudomonas aeruginosa. Expression of the T3SS is controlled under a complicate regulatory network. In this study, we demonstrate that NrtR (PA4916) is involved in the T3SS expression and pathogenesis of P. aeruginosa in a mouse acute pneumonia model. Overexpression of the T3SS central activator ExsA or exogenous supplementation of cAMP restored the expression of T3SS in the ΔnrtR mutant, suggesting that NrtR might regulate T3SS through the cAMP-Vfr signaling pathway. Further experiments demonstrated that the decrease of cAMP content is not due to the expression change of adenylate cyclases or phosphodiesterase in the ΔnrtR mutant. As it has been shown that nadD2 is upregulated in the ΔnrtR mutant, we overexpressed nadD2 in wild type PAK, which reduced the intracellular cAMP level and the expression of the T3SS genes. Meanwhile, deletion of nadD2 in the ΔnrtR mutant restored the expression and secretion of the T3SS. Co-immunoprecipitation assay revealed an interaction between NadD2 and the catalytic domain of the adenylate cyclase CyaB. Further in vitro assay indicated that NadD2 repressed the enzymatic activity of CyaB. Therefore, we have identified a novel regulatory mechanism of T3SS in P. aeruginosa.
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Affiliation(s)
- 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, China
| | - Mengjing 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, China
| | - Feng Zhu
- 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, China
| | - Qianqian Peng
- 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, China
| | - Yuding Weng
- 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, China
| | - Qiang Zhao
- College of Life Sciences, Nankai University, Tianjin, China
| | - Chang Liu
- 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, 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, 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, China
| | - Shouguang Jin
- Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL, United States
| | - 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, China
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28
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cAMP and Vfr Control Exolysin Expression and Cytotoxicity of Pseudomonas aeruginosa Taxonomic Outliers. J Bacteriol 2018; 200:JB.00135-18. [PMID: 29632090 DOI: 10.1128/jb.00135-18] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 04/04/2018] [Indexed: 12/22/2022] Open
Abstract
The two-partner secretion system ExlBA, expressed by strains of Pseudomonas aeruginosa belonging to the PA7 group, induces hemorrhage in lungs due to disruption of host cellular membranes. Here we demonstrate that the exlBA genes are controlled by a pathway consisting of cAMP and the virulence factor regulator (Vfr). Upon interaction with cAMP, Vfr binds directly to the exlBA promoter with high affinity (equilibrium binding constant [Keq] of ≈2.5 nM). The exlB and exlA expression was diminished in the Vfr-negative mutant and upregulated with increased intracellular cAMP levels. The Vfr binding sequence in the exlBA promoter was mutated in situ, resulting in reduced cytotoxicity of the mutant, showing that Vfr is required for the exlBA expression during intoxication of epithelial cells. Vfr also regulates function of type 4 pili previously shown to facilitate ExlA activity on epithelial cells, which indicates that the cAMP/Vfr pathway coordinates these two factors needed for full cytotoxicity. As in most P. aeruginosa strains, the adenylate cyclase CyaB is the main provider of cAMP for Vfr regulation during both in vitro growth and eukaryotic cell infection. We discovered that the absence of functional Vfr in the reference strain PA7 is caused by a frameshift in the gene and accounts for its reduced cytotoxicity, revealing the conservation of ExlBA control by the CyaB-cAMP/Vfr pathway in P. aeruginosa taxonomic outliers.IMPORTANCE The human opportunistic pathogen Pseudomonas aeruginosa provokes severe acute and chronic human infections associated with defined sets of virulence factors. The main virulence determinant of P. aeruginosa taxonomic outliers is exolysin, a membrane-disrupting pore-forming toxin belonging to the two-partner secretion system ExlBA. In this work, we demonstrate that the conserved CyaB-cAMP/Vfr pathway controls cytotoxicity of outlier clinical strains through direct transcriptional activation of the exlBA operon. Therefore, despite the fact that the type III secretion system and exolysin are mutually exclusive in classical and outlier strains, respectively, these two major virulence determinants share similarities in their mechanisms of regulation.
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29
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Zhang Y, Li J, Zhang W, Shi H, Luo F, Hikichi Y, Shi X, Ohnishi K. A putative LysR-type transcriptional regulator PrhO positively regulates the type III secretion system and contributes to the virulence of Ralstonia solanacearum. MOLECULAR PLANT PATHOLOGY 2018; 19:1808-1819. [PMID: 29363870 PMCID: PMC6638147 DOI: 10.1111/mpp.12660] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Revised: 12/21/2017] [Accepted: 01/20/2018] [Indexed: 06/01/2023]
Abstract
LysR-type transcriptional regulators (LTTRs) are ubiquitous and abundant amongst bacteria and control a variety of cellular processes. Here, we investigated the effect of Rsc1880 (a putative LTTR, hereafter designated as PrhO) on the pathogenicity of Ralstonia solanacearum. Deletion of prhO substantially reduced the expression of the type III secretion system (T3SS) both in vitro and in planta, and resulted in significantly impaired virulence in tomato and tobacco plants. Complementary prhO completely restored the reduced virulence and T3SS expression to that of the wild-type. Moreover, PrhO-dependent T3SS and virulence were conserved amongst R. solanacearum species. However, deletion of prhO did not alter biofilm formation, swimming mobility and in planta growth. The expression of some type III effectors was significantly reduced in prhO mutants, but the hypersensitive response was not affected in tobacco leaves. Consistent with the key regulatory role of HrpB on T3SS, PrhO positively regulated the T3SS through HrpB. Furthermore, PrhO regulated hrpB expression via two close paralogues, HrpG and PrhG, which are two-component response regulators and positively regulate hrpB expression in a parallel manner. However, deletion of prhO did not alter the expression of phcA, prhJ and prhN, which are also involved in hrpB regulation. In addition, PrhO was expressed in a cell density-dependent manner, but negatively repressed by itself. No regulation was observed for HrpB, PhcA and PrhN on prhO expression. Taken together, we genetically demonstrated that PrhO is a novel virulence regulator of R. solanacearum, which positively regulates T3SS expression through HrpG, PrhG and HrpB and contributes to virulence.
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Affiliation(s)
- Yong Zhang
- College of Resources and EnvironmentSouthwest UniversityChongqing400715China
| | - Jiaman Li
- College of Resources and EnvironmentSouthwest UniversityChongqing400715China
| | - Weiqi Zhang
- College of Resources and EnvironmentSouthwest UniversityChongqing400715China
| | - Hualei Shi
- College of Resources and EnvironmentSouthwest UniversityChongqing400715China
| | - Feng Luo
- Research Center of Bioenergy and Bioremediation, College of Resources and EnvironmentSouthwest UniversityChongqing400715China
| | - Yasufumi Hikichi
- Laboratory of Plant Pathology and BiotechnologyKochi UniversityKochi783‐8502Japan
| | - Xiaojun Shi
- College of Resources and EnvironmentSouthwest UniversityChongqing400715China
| | - Kouhei Ohnishi
- Research Institute of Molecular GeneticsKochi UniversityKochi783‐8502Japan
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30
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Toxic Electrophiles Induce Expression of the Multidrug Efflux Pump MexEF-OprN in Pseudomonas aeruginosa through a Novel Transcriptional Regulator, CmrA. Antimicrob Agents Chemother 2017; 61:AAC.00585-17. [PMID: 28507116 DOI: 10.1128/aac.00585-17] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 05/11/2017] [Indexed: 11/20/2022] Open
Abstract
The multidrug efflux system MexEF-OprN is produced at low levels in wild-type strains of Pseudomonas aeruginosa However, in so-called nfxC mutants, mutational alteration of the gene mexS results in constitutive overexpression of the pump, along with increased resistance of the bacterium to chloramphenicol, fluoroquinolones, and trimethoprim. In this study, analysis of in vitro-selected chloramphenicol-resistant clones of strain PA14 led to the identification of a new class of MexEF-OprN-overproducing mutants (called nfxC2) exhibiting alterations in an as-yet-uncharacterized gene, PA14_38040 (homolog of PA2047 in strain PAO1). This gene is predicted to encode an AraC-like transcriptional regulator and was called cmrA (for chloramphenicol resistance activator). In nfxC2 mutants, the mutated CmrA increases its proper gene expression and upregulates the operon mexEF-oprN through MexS and MexT, resulting in a multidrug resistance phenotype without significant loss in bacterial virulence. Transcriptomic experiments demonstrated that CmrA positively regulates a small set of 11 genes, including PA14_38020 (homolog of PA2048), which is required for the MexS/T-dependent activation of mexEF-oprN PA2048 codes for a protein sharing conserved domains with the quinol monooxygenase YgiN from Escherichia coli Interestingly, exposure of strain PA14 to toxic electrophilic molecules (glyoxal, methylglyoxal, and cinnamaldehyde) strongly activates the CmrA pathway and upregulates MexEF-OprN and, thus, increases the resistance of P. aeruginosa to the pump substrates. A picture emerges in which MexEF-OprN is central in the response of the pathogen to stresses affecting intracellular redox homeostasis.
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31
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Tan H, Zhang L, Zhao Q, Chen R, Liu C, Weng Y, Peng Q, Bai F, Cheng Z, Jin S, Wu W, Jin Y. DeaD contributes to Pseudomonas aeruginosa virulence in a mouse acute pneumonia model. FEMS Microbiol Lett 2016; 363:fnw227. [PMID: 27682417 DOI: 10.1093/femsle/fnw227] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/27/2016] [Indexed: 02/05/2023] Open
Abstract
DExD/H box RNA helicases play essential roles in various biological processes in prokaryotes and eukaryotes. By screening Pseudomonas aeruginosa strains with mutations in various DExD/H box helicase genes, we identified that deaD was required for bacterial cytotoxicity and virulence in a mouse acute pneumonia model. Compared to a wild-type strain and its complementation strain, the deaD mutant induced less production of proinflammatory cytokines, neutrophil infiltration and lung damage during infection. We further found that the RNA helicase activity of DeaD was required for the expression of type III secretion system (T3SS) genes. Overexpression of ExsA, a master activator of the T3SS, restored the expression of T3SS genes as well as the virulence of the deaD mutant, suggesting that the attenuated virulence of the deaD mutant was mainly due to the defective T3SS. Overall, our results reveal a role of DeaD in the virulence of P. aeruginosa.
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Affiliation(s)
- Hao Tan
- 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
| | - Lu 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
| | - Qiang Zhao
- College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Ronghao Chen
- 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
| | - Chang Liu
- 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
| | - Yuding Weng
- 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
| | - Qianqian Peng
- 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, College of Pharmacyand Life Sciences, and Tianjin Key Laboratory of Molecular Drug Research, 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
| | - Shouguang Jin
- Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - 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
| | - 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
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Alcalde-Rico M, Hernando-Amado S, Blanco P, Martínez JL. Multidrug Efflux Pumps at the Crossroad between Antibiotic Resistance and Bacterial Virulence. Front Microbiol 2016; 7:1483. [PMID: 27708632 PMCID: PMC5030252 DOI: 10.3389/fmicb.2016.01483] [Citation(s) in RCA: 138] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Accepted: 09/06/2016] [Indexed: 01/24/2023] Open
Abstract
Multidrug efflux pumps can be involved in bacterial resistance to antibiotics at different levels. Some efflux pumps are constitutively expressed at low levels and contribute to intrinsic resistance. In addition, their overexpression may allow higher levels of resistance. This overexpression can be transient, in the presence of an effector (phenotypic resistance), or constitutive when mutants in the regulatory elements of the expression of efflux pumps are selected (acquired resistance). Efflux pumps are present in all cells, from human to bacteria and are highly conserved, which indicates that they are ancient elements in the evolution of different organisms. Consequently, it has been suggested that, besides antibiotic resistance, bacterial multidrug efflux pumps would likely contribute to other relevant processes of the microbial physiology. In the current article, we discuss some specific examples of the role that efflux pumps may have in the bacterial virulence of animals’ and plants’ pathogens, including the processes of intercellular communication. Based in these evidences, we propose that efflux pumps are at the crossroad between resistance and virulence of bacterial pathogens. Consequently, the comprehensive study of multidrug efflux pumps requires addressing these functions, which are of relevance for the bacterial–host interactions during infection.
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Affiliation(s)
- Manuel Alcalde-Rico
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas Madrid, Spain
| | - Sara Hernando-Amado
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas Madrid, Spain
| | - Paula Blanco
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas Madrid, Spain
| | - José L Martínez
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas Madrid, Spain
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Amino Acid Substitutions Account for Most MexS Alterations in Clinical nfxC Mutants of Pseudomonas aeruginosa. Antimicrob Agents Chemother 2016; 60:2302-10. [PMID: 26833155 DOI: 10.1128/aac.02622-15] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Accepted: 01/25/2016] [Indexed: 11/20/2022] Open
Abstract
Multidrug-resistant mutants ofPseudomonas aeruginosathat overproduce the active efflux system MexEF-OprN (callednfxCmutants) have rarely been characterized in the hospital setting. Screening of 221 clinical strains exhibiting a reduced susceptibility to ciprofloxacin (a substrate of MexEF-OprN) and imipenem (a substrate of the negatively coregulated porin OprD) led to the identification of 43 (19.5%)nfxCmutants. Subsequent analysis of 22 nonredundant mutants showed that, in contrast to theirin vitro-selected counterparts, only 3 of them (13.6%) harbored a disruptedmexSgene, which codes for the oxidoreductase MexS, whose inactivation is known to activate themexEF-oprNoperon through a LysR-type regulator, MexT. Nine (40.9%) of the clinicalnfxCmutants contained single amino acid mutations in MexS, and these were associated with moderate effects on resistance and virulence factor production in 8/9 strains. Finally, the remaining 10 (45.5%)nfxCmutants did not display mutations in any of the regulators known to controlmexEF-oprNexpression (themexS,mexT,mvaT, andampRgenes), confirming that other loci are responsible for pump upregulation in patients. Collectively, these data demonstrate thatnfxCmutants are probably more frequent in the hospital than previously thought and have genetic and phenotypic features somewhat different from those ofin vitro-selected mutants.
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Li XZ, Plésiat P, Nikaido H. The challenge of efflux-mediated antibiotic resistance in Gram-negative bacteria. Clin Microbiol Rev 2015; 28:337-418. [PMID: 25788514 PMCID: PMC4402952 DOI: 10.1128/cmr.00117-14] [Citation(s) in RCA: 920] [Impact Index Per Article: 102.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The global emergence of multidrug-resistant Gram-negative bacteria is a growing threat to antibiotic therapy. The chromosomally encoded drug efflux mechanisms that are ubiquitous in these bacteria greatly contribute to antibiotic resistance and present a major challenge for antibiotic development. Multidrug pumps, particularly those represented by the clinically relevant AcrAB-TolC and Mex pumps of the resistance-nodulation-division (RND) superfamily, not only mediate intrinsic and acquired multidrug resistance (MDR) but also are involved in other functions, including the bacterial stress response and pathogenicity. Additionally, efflux pumps interact synergistically with other resistance mechanisms (e.g., with the outer membrane permeability barrier) to increase resistance levels. Since the discovery of RND pumps in the early 1990s, remarkable scientific and technological advances have allowed for an in-depth understanding of the structural and biochemical basis, substrate profiles, molecular regulation, and inhibition of MDR pumps. However, the development of clinically useful efflux pump inhibitors and/or new antibiotics that can bypass pump effects continues to be a challenge. Plasmid-borne efflux pump genes (including those for RND pumps) have increasingly been identified. This article highlights the recent progress obtained for organisms of clinical significance, together with methodological considerations for the characterization of MDR pumps.
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Affiliation(s)
- Xian-Zhi Li
- Human Safety Division, Veterinary Drugs Directorate, Health Products and Food Branch, Health Canada, Ottawa, Ontario, Canada
| | - Patrick Plésiat
- Laboratoire de Bactériologie, Faculté de Médecine-Pharmacie, Centre Hospitalier Régional Universitaire, Université de Franche-Comté, Besançon, France
| | - Hiroshi Nikaido
- Department of Molecular and Cell Biology, University of California, Berkeley, California, USA
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Morita Y, Tomida J, Kawamura Y. Efflux-mediated fluoroquinolone resistance in the multidrug-resistant Pseudomonas aeruginosa clinical isolate PA7: identification of a novel MexS variant involved in upregulation of the mexEF-oprN multidrug efflux operon. Front Microbiol 2015; 6:8. [PMID: 25653649 PMCID: PMC4301020 DOI: 10.3389/fmicb.2015.00008] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Accepted: 01/05/2015] [Indexed: 11/24/2022] Open
Abstract
The emergence of multidrug-resistant Pseudomonas aeruginosa has become a serious problem in medical settings. P. aeruginosa clinical isolate PA7 is resistant to fluoroquinolones, aminoglycosides, and most β-lactams but not imipenem. In this study, enhanced efflux-mediated fluoroquinolone resistance of PA7 was shown to reflect increased expression of two resistance nodulation cell division (RND) -type multidrug efflux operons, mexEF-oprN and mexXY-oprA. Such a clinical isolate has rarely been reported because MexEF-OprN-overproducing mutants often increase susceptibility to aminoglycosides apparently owing to impairment of the MexXY system. A mutant of PA7 lacking three RND-type multidrug efflux operons (mexAB-oprM, mexEF-oprN, and mexXY-oprA) was susceptible to all anti-pseudomonas agents we tested, supporting an idea that these RND-type multidrug efflux transporters are molecular targets to overcome multidrug resistance in P. aeruginosa. mexEF-oprN-upregulation in P. aeruginosa PA7 was shown due to a MexS variant harboring the Valine-155 amino acid residue. This is the first genetic evidence shown that a MexS variant causes mexEF-oprN-upregulation in P. aeruginosa clinical isolates.
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Affiliation(s)
- Yuji Morita
- Department of Microbiology, School of Pharmacy, Aichi Gakuin University Nagoya, Japan
| | - Junko Tomida
- Department of Microbiology, School of Pharmacy, Aichi Gakuin University Nagoya, Japan
| | - Yoshiaki Kawamura
- Department of Microbiology, School of Pharmacy, Aichi Gakuin University Nagoya, Japan
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Guillemot L, Medina M, Pernet E, Leduc D, Chignard M, Touqui L, Wu Y. Cytosolic phospholipase A2α enhances mouse mortality induced by Pseudomonas aeruginosa pulmonary infection via interleukin 6. Biochimie 2014; 107 Pt A:95-104. [PMID: 25201511 DOI: 10.1016/j.biochi.2014.08.018] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 08/29/2014] [Indexed: 12/19/2022]
Abstract
Pseudomonas aeruginosa pulmonary infection is a leading cause of death in numerous diseases such as cystic fibrosis (CF). The host cytosolic phospholipase A2α (cPLA2α) releases lipid mediators that play an important role in the pathogenesis of diseases, but its role in lung injury induced by P. aeruginosa infection is still obscure. Using an animal model of P. aeruginosa lung infection, we showed that the CHA strain of P. aeruginosa was more potent than the PAK strain in inducing mouse mortality and lung injury, and that both mouse mortality and lung injury were reduced in cPLA2α(-/-) mice as compared to cPLA2α(+/+) mice. This was accompanied by decreased levels of IL6 but not other inflammatory cytokines (IL1β, KC and TNFα) in the bronchoalveolar lavage fluids (BALFs) of cPLA2α(-/-) mice. Given that CFTR(-/-) mice exhibit increased cPLA2α activation in the lung, the role of cPLA2α was further examined in this lung infection model. Compared to littermates, P. aeruginosa infection caused increased mortality in CFTR(-/-) mice with high IL6 levels in BALFs, which was attenuated by pharmacological inhibition of cPLA2α. In addition, compared to IL6(-/-) mice, an enhanced mortality was also observed in P. aeruginosa infected IL6(+/+) mice. Since alveolar macrophages (AMs) are the primary inflammatory cytokine source in the lung, murine AMs cell line (MH-S) were used to investigate the signalling pathways involved in this process. Incubation of MH-S cells with P. aeruginosa induced IL6 production, which was mediated by MAPKs ERK/p38 and was abolished by cPLA2α inhibitors. Furthermore, among cPLA2 downstream signalling pathways, only 15-lipoxygenase (15-LOX) and cyclooxygenase-2 (COX-2) were proven to participate in this P. aeruginosa-induced IL6 expression. Based on all these observations, we conclude that cPLA2α enhances P. aeruginosa-induced animal lethality in part via IL6 induction and that MAPKs ERK/p38, 15-LOX and COX-2 signalling pathways were involved in this process.
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Affiliation(s)
- Laurent Guillemot
- Unit of Innate Defence & Inflammation, Institut Pasteur, 25 rue Dr Roux, 75015 Paris, France; INSERM U874, 25 rue Dr Roux, 75015 Paris, France
| | - Mathieu Medina
- Unit of Innate Defence & Inflammation, Institut Pasteur, 25 rue Dr Roux, 75015 Paris, France; INSERM U874, 25 rue Dr Roux, 75015 Paris, France
| | - Erwan Pernet
- Unit of Innate Defence & Inflammation, Institut Pasteur, 25 rue Dr Roux, 75015 Paris, France; INSERM U874, 25 rue Dr Roux, 75015 Paris, France
| | - Dominique Leduc
- Unit of Innate Defence & Inflammation, Institut Pasteur, 25 rue Dr Roux, 75015 Paris, France; INSERM U874, 25 rue Dr Roux, 75015 Paris, France
| | - Michel Chignard
- Unit of Innate Defence & Inflammation, Institut Pasteur, 25 rue Dr Roux, 75015 Paris, France; INSERM U874, 25 rue Dr Roux, 75015 Paris, France
| | - Lhousseine Touqui
- Unit of Innate Defence & Inflammation, Institut Pasteur, 25 rue Dr Roux, 75015 Paris, France; INSERM U874, 25 rue Dr Roux, 75015 Paris, France
| | - Yongzheng Wu
- Unit of Innate Defence & Inflammation, Institut Pasteur, 25 rue Dr Roux, 75015 Paris, France; INSERM U874, 25 rue Dr Roux, 75015 Paris, France.
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McCarthy RR, Mooij MJ, Reen FJ, Lesouhaitier O, O'Gara F. A new regulator of pathogenicity (bvlR) is required for full virulence and tight microcolony formation in Pseudomonas aeruginosa. MICROBIOLOGY (READING, ENGLAND) 2014; 160:1488-1500. [PMID: 24829363 DOI: 10.1099/mic.0.075291-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
LysR-type transcriptional regulators (LTTRs) are the most common family of transcriptional regulators found in the opportunistic pathogen Pseudomonas aeruginosa. They are known to regulate a wide variety of virulence determinants and have emerged recently as positive global regulators of pathogenicity in a broad spectrum of important bacterial pathogens. However, in spite of their key role in modulating expression of key virulence determinants underpinning pathogenic traits associated with the process of infection, surprisingly few are found to be transcriptionally altered by contact with host cells. BvlR (PA14_26880) an LTTR of previously unknown function, has been shown to be induced in response to host cell contact, and was therefore investigated for its potential role in virulence. BvlR expression was found to play a pivotal role in the regulation of acute virulence determinants such as type III secretion system and exotoxin A production. BvlR also played a key role in P. aeruginosa pathogenicity within the Caenorhabditis elegans acute model of infection. Loss of BvlR led to an inability to form tight microcolonies, a key step in biofilm formation in the cystic fibrosis lung, although surface attachment was increased. Unusually for LTTRs, BvlR was shown to exert its influence through the transcriptional repression of many genes, including the virulence-associated cupA and alg genes. This highlights the importance of BvlR as a new virulence regulator in P. aeruginosa with a central role in modulating key events in the pathogen-host interactome.
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Affiliation(s)
- Ronan R McCarthy
- BIOMERIT Research Centre, School of Microbiology, University College Cork, Cork, Ireland
| | - Marlies J Mooij
- BIOMERIT Research Centre, School of Microbiology, University College Cork, Cork, Ireland
| | - F Jerry Reen
- BIOMERIT Research Centre, School of Microbiology, University College Cork, Cork, Ireland
| | - Olivier Lesouhaitier
- Laboratory of Microbiology Signals and Microenvironment LMSM EA4312, University of Rouen, 55 rue Saint Germain, 27000 Evreux, France
| | - Fergal O'Gara
- Curtin University, School of Biomedical Sciences, Perth, WA, Australia
- BIOMERIT Research Centre, School of Microbiology, University College Cork, Cork, Ireland
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Emergence of the P2 phenotype in Pseudomonas aeruginosa PAO1 strains involves various mutations in mexT or mexF. J Bacteriol 2013; 196:504-13. [PMID: 24244000 DOI: 10.1128/jb.01050-13] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We recently demonstrated that Pseudomonas aeruginosa PAO1 undergoes a pronounced phenotypic change when introduced into the intestines of rats during surgical injury. Recovered strains displayed a specific phenotype (termed the P2 phenotype) characterized by altered pyocyanin production, high collagenase activity, high swarming motility, low resistance to chloramphenicol, and increased killing of Caenorhabditis elegans compared to the inoculating strain (termed the P1 phenotype). The aims of this study were to characterize the differences between the P. aeruginosa P1 and P2 phenotypes in quorum sensing and competitiveness. We then determined the presence of the P2 phenotype among PAO1 strains from various laboratories. Results demonstrated that P2 cells display accelerated growth during early exponential phase and early activation of quorum-sensing systems and overcome the growth of P1 cells in a mixed population. Among eight PAO1 strains obtained from different laboratories, four exhibited the P2 phenotype. Of 27 mutants analyzed from the P. aeruginosa MPAO1 transposon library, 25 displayed P2 phenotypes. The P2 phenotype in both cases correlated with a lack of expression of mexE or mexF due to mutations in mexT and mexF genes. In summary, strains possessing the P2 phenotype are distributed among PAO1 strains commonly used across a variety of research laboratories. Genetically, they are characterized by various mutations in mexT or mexF.
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SuhB is a regulator of multiple virulence genes and essential for pathogenesis of Pseudomonas aeruginosa. mBio 2013; 4:e00419-13. [PMID: 24169572 PMCID: PMC3809559 DOI: 10.1128/mbio.00419-13] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
During initial colonization and chronic infection, pathogenic bacteria encounter distinct host environments. Adjusting gene expression accordingly is essential for the pathogenesis. Pseudomonas aeruginosa has evolved complicated regulatory networks to regulate different sets of virulence factors to facilitate colonization and persistence. The type III secretion system (T3SS) and motility are associated with acute infections, while biofilm formation and the type VI secretion system (T6SS) are associated with chronic persistence. To identify novel regulatory genes required for pathogenesis, we screened a P. aeruginosa transposon (Tn) insertion library and found suhB to be an essential gene for the T3SS gene expression. The expression of suhB was upregulated in a mouse acute lung infection model, and loss of suhB resulted in avirulence. Suppression of T3SS gene expression in the suhB mutant is linked to a defective translation of the T3SS master regulator, ExsA. Further studies demonstrated that suhB mutation led to the upregulation of GacA and its downstream small RNAs, RsmY and RsmZ, triggering T6SS expression and biofilm formation while inhibiting the T3SS. Our results demonstrate that an in vivo-inducible gene, suhB, reciprocally regulates genes associated with acute and chronic infections and plays an essential role in the pathogenesis of P. aeruginosa. A variety of bacterial pathogens, such as Pseudomonas aeruginosa, cause acute and chronic infections in humans. During infections, pathogens produce different sets of virulence genes for colonization, tissue damage, and dissemination and for countering host immune responses. Complex regulatory networks control the delicate tuning of gene expression in response to host environments to enable the survival and growth of invading pathogens. Here we identified suhB as a critical gene for the regulation of virulence factors in P. aeruginosa. The expression of suhB was upregulated during acute infection in an animal model, and mutation of suhB rendered P. aeruginosa avirulent. Moreover, we demonstrate that SuhB is required for the activation of virulence factors associated with acute infections while suppressing virulence factors associated with chronic infections. Our report provides new insights into the multilayered regulatory network of virulence genes in P. aeruginosa.
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Stern JR, Olivas AD, Valuckaite V, Zaborina O, Alverdy JC, An G. Agent-based model of epithelial host-pathogen interactions in anastomotic leak. J Surg Res 2013; 184:730-8. [PMID: 23290531 PMCID: PMC4184143 DOI: 10.1016/j.jss.2012.12.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Revised: 11/24/2012] [Accepted: 12/06/2012] [Indexed: 10/27/2022]
Abstract
BACKGROUND There is a growing recognition of the significance of host-pathogen interactions (HPIs) in gut biology leading to a reassessment of the role of bacteria in intestinal anastomotic leak. Understanding the complexities of the early postsurgical gut HPI requires integrating knowledge of both epithelial and bacterial behaviors to generate hypotheses of potential mechanisms of interaction. Agent-based modeling is a computational method well suited to achieve this goal, and we use an agent-based model (ABM) to examine alterations in the HPI affecting reestablishment of the epithelial barrier that may subsequently lead to anastomotic leak. METHODS Computational agents representing Pseudomonas aeruginosa were added to a previously validated ABM of epithelial restitution. Simulated experiments were performed examining the effect of radiation on bacterial binding to epithelial cells, plausibility of putative binding targets, and potential mechanisms of epithelial cell killing by virulent bacteria. RESULTS Simulation experiments incorporating radiation effects on epithelial monolayers produced binding patterns akin to those seen in vitro and suggested that promotility integrin-laminin associations represent potential sites for bacterial binding and disruption of restitution. Simulations of potential mechanisms of epithelial cell killing suggested that an injected cytotoxin was the means by which virulent bacteria produced the tissue destruction needed to generate an anastomotic leak, a mechanism subsequently confirmed with genotyping of the virulent P aeruginosa strain. CONCLUSIONS This study emphasizes the utility of ABM as an adjunct to traditional research methods and provides insights into the potentially critical role of HPI in the pathogenesis of anastomotic leak.
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Affiliation(s)
| | | | | | | | | | - Gary An
- The University of Chicago, Department of Surgery
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41
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Uwate M, Ichise YK, Shirai A, Omasa T, Nakae T, Maseda H. Two routes of MexS-MexT-mediated regulation of MexEF-OprN and MexAB-OprM efflux pump expression inPseudomonas aeruginosa. Microbiol Immunol 2013; 57:263-72. [DOI: 10.1111/1348-0421.12032] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Revised: 01/16/2013] [Accepted: 01/22/2013] [Indexed: 11/27/2022]
Affiliation(s)
- Maki Uwate
- Institute of Technology and Science; The University of Tokushima Graduate School, 2-1 Minamijosanjima-cho; Tokushima; 770-8506
| | - Yu-ki Ichise
- Institute of Technology and Science; The University of Tokushima Graduate School, 2-1 Minamijosanjima-cho; Tokushima; 770-8506
| | - Akihiro Shirai
- Institute of Technology and Science; The University of Tokushima Graduate School, 2-1 Minamijosanjima-cho; Tokushima; 770-8506
| | - Takeshi Omasa
- Institute of Technology and Science; The University of Tokushima Graduate School, 2-1 Minamijosanjima-cho; Tokushima; 770-8506
| | - Taiji Nakae
- Laboratory for Antimicrobial Agents; Kitasato Institute for Life Sciences, Kitasato University, 5-9-1 Shirokane; Minato-Ku, Tokyo; 108-8641; Japan
| | - Hideaki Maseda
- Institute of Technology and Science; The University of Tokushima Graduate School, 2-1 Minamijosanjima-cho; Tokushima; 770-8506
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Adaptive and mutational resistance: role of porins and efflux pumps in drug resistance. Clin Microbiol Rev 2013; 25:661-81. [PMID: 23034325 DOI: 10.1128/cmr.00043-12] [Citation(s) in RCA: 530] [Impact Index Per Article: 48.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The substantial use of antibiotics in the clinic, combined with a dearth of new antibiotic classes, has led to a gradual increase in the resistance of bacterial pathogens to these compounds. Among the various mechanisms by which bacteria endure the action of antibiotics, those affecting influx and efflux are of particular importance, as they limit the interaction of the drug with its intracellular targets and, consequently, its deleterious effects on the cell. This review evaluates the impact of porins and efflux pumps on two major types of resistance, namely, mutational and adaptive types of resistance, both of which are regarded as key phenomena in the global rise of antibiotic resistance among pathogenic microorganisms. In particular, we explain how adaptive and mutational events can dramatically influence the outcome of antibiotic therapy by altering the mechanisms of influx and efflux of antibiotics. The identification of porins and pumps as major resistance markers has opened new possibilities for the development of novel therapeutic strategies directed specifically against these mechanisms.
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Dong YH, Zhang XF, Zhang LH. The global regulator Crc plays a multifaceted role in modulation of type III secretion system in Pseudomonas aeruginosa. Microbiologyopen 2013; 2:161-72. [PMID: 23292701 PMCID: PMC3584221 DOI: 10.1002/mbo3.54] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2012] [Revised: 10/29/2012] [Accepted: 11/05/2012] [Indexed: 11/22/2022] Open
Abstract
The opportunistic pathogen Pseudomonas aeruginosa utilizes type III secretion system (T3SS) to translocate effector proteins into eukaryotic host cells that subvert normal host cell functions to the benefit of the pathogen, and results in serious infections. T3SS in P. aeruginosa is controlled by a complex system of regulatory mechanisms and signaling pathways. In this study, we described that Crc, an RNA-binding protein, exerts a positive impact on T3SS in P. aeruginosa, as evidenced by promoter activity assays of several key T3SS genes, transcriptomics, RT-PCR, and immunoblotting in crc mutant. We further demonstrated that the regulatory function of Crc on the T3SS was mediated through the T3SS master regulator ExsA and linked to the Cbr/Crc signaling system. Expression profiling of the crc mutant revealed a downregulation of flagship T3SS genes as well as 16 other genes known to regulate T3SS gene expression in P. aeruginosa. On the basis of these data, we proposed that Crc may exert multifaceted control on the T3SS through various pathways, which may serve to fine-tune this virulence mechanism in response to environmental changes and nutrient sources.
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Affiliation(s)
- Yi-Hu Dong
- Institute of Molecular and Cell Biology, 61 Biopolis Drive, Singapore, 138673.
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Balasubramanian D, Schneper L, Kumari H, Mathee K. A dynamic and intricate regulatory network determines Pseudomonas aeruginosa virulence. Nucleic Acids Res 2012; 41:1-20. [PMID: 23143271 PMCID: PMC3592444 DOI: 10.1093/nar/gks1039] [Citation(s) in RCA: 317] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Pseudomonas aeruginosa is a metabolically versatile bacterium that is found in a wide range of biotic and abiotic habitats. It is a major human opportunistic pathogen causing numerous acute and chronic infections. The critical traits contributing to the pathogenic potential of P. aeruginosa are the production of a myriad of virulence factors, formation of biofilms and antibiotic resistance. Expression of these traits is under stringent regulation, and it responds to largely unidentified environmental signals. This review is focused on providing a global picture of virulence gene regulation in P. aeruginosa. In addition to key regulatory pathways that control the transition from acute to chronic infection phenotypes, some regulators have been identified that modulate multiple virulence mechanisms. Despite of a propensity for chaotic behaviour, no chaotic motifs were readily observed in the P. aeruginosa virulence regulatory network. Having a ‘birds-eye’ view of the regulatory cascades provides the forum opportunities to pose questions, formulate hypotheses and evaluate theories in elucidating P. aeruginosa pathogenesis. Understanding the mechanisms involved in making P. aeruginosa a successful pathogen is essential in helping devise control strategies.
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Affiliation(s)
- Deepak Balasubramanian
- Department of Biological Sciences, College of Arts and Science, Florida International University, Miami, FL 33199, USA
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Olivas AD, Shogan BD, Valuckaite V, Zaborin A, Belogortseva N, Musch M, Meyer F, L.Trimble W, An G, Gilbert J, Zaborina O, Alverdy JC. Intestinal tissues induce an SNP mutation in Pseudomonas aeruginosa that enhances its virulence: possible role in anastomotic leak. PLoS One 2012; 7:e44326. [PMID: 22952955 PMCID: PMC3432121 DOI: 10.1371/journal.pone.0044326] [Citation(s) in RCA: 132] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Accepted: 08/01/2012] [Indexed: 12/14/2022] Open
Abstract
The most feared complication following intestinal resection is anastomotic leakage. In high risk areas (esophagus/rectum) where neoadjuvant chemoradiation is used, the incidence of anastomotic leaks remains unacceptably high (∼10%) even when performed by specialist surgeons in high volume centers. The aims of this study were to test the hypothesis that anastomotic leakage develops when pathogens colonizing anastomotic sites become in vivo transformed to express a tissue destroying phenotype. We developed a novel model of anastomotic leak in which rats were exposed to pre-operative radiation as in cancer surgery, underwent distal colon resection and then were intestinally inoculated with Pseudomonas aeruginosa, a common colonizer of the radiated intestine. Results demonstrated that intestinal tissues exposed to preoperative radiation developed a significant incidence of anastomotic leak (>60%; p<0.01) when colonized by P. aeruginosa compared to radiated tissues alone (0%). Phenotype analysis comparing the original inoculating strain (MPAO1- termed P1) and the strain retrieved from leaking anastomotic tissues (termed P2) demonstrated that P2 was altered in pyocyanin production and displayed enhanced collagenase activity, high swarming motility, and a destructive phenotype against cultured intestinal epithelial cells (i.e. apoptosis, barrier function, cytolysis). Comparative genotype analysis between P1 and P2 revealed a single nucleotide polymorphism (SNP) mutation in the mexT gene that led to a stop codon resulting in a non-functional truncated protein. Replacement of the mutated mexT gene in P2 with mexT from the original parental strain P1 led to reversion of P2 to the P1 phenotype. No spontaneous transformation was detected during 20 passages in TSB media. Use of a novel virulence suppressing compound PEG/Pi prevented P. aeruginosa transformation to the tissue destructive phenotype and prevented anastomotic leak in rats. This work demonstrates that in vivo transformation of microbial pathogens to a tissue destroying phenotype may have important implications in the pathogenesis of anastomotic leak.
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Affiliation(s)
- Andrea D. Olivas
- Department of Surgery, University of Chicago, Illinois, United States of America
| | - Benjamin D. Shogan
- Department of Surgery, University of Chicago, Illinois, United States of America
| | - Vesta Valuckaite
- Department of Surgery, University of Chicago, Illinois, United States of America
- Bioengineering Institute for Advanced Surgery and Endoscopy, Chicago, Illinois, United States of America
| | - Alexander Zaborin
- Department of Surgery, University of Chicago, Illinois, United States of America
| | - Natalya Belogortseva
- Department of Surgery, University of Chicago, Illinois, United States of America
| | - Mark Musch
- Department of Medicine, University of Chicago, Chicago, Illinois, United States of America
| | - Folker Meyer
- Institute for Genomic and Systems Biology, Argonne National Laboratory, Argonne, Illinois, United States of America
| | - William L.Trimble
- Institute for Genomic and Systems Biology, Argonne National Laboratory, Argonne, Illinois, United States of America
| | - Gary An
- Department of Surgery, University of Chicago, Illinois, United States of America
| | - Jack Gilbert
- Institute for Genomic and Systems Biology, Argonne National Laboratory, Argonne, Illinois, United States of America
| | - Olga Zaborina
- Department of Surgery, University of Chicago, Illinois, United States of America
| | - John C. Alverdy
- Department of Surgery, University of Chicago, Illinois, United States of America
- Bioengineering Institute for Advanced Surgery and Endoscopy, Chicago, Illinois, United States of America
- * E-mail:
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46
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Klockgether J, Miethke N, Kubesch P, Bohn YS, Brockhausen I, Cramer N, Eberl L, Greipel J, Herrmann C, Herrmann S, Horatzek S, Lingner M, Luciano L, Salunkhe P, Schomburg D, Wehsling M, Wiehlmann L, Davenport CF, Tümmler B. Intraclonal diversity of the Pseudomonas aeruginosa cystic fibrosis airway isolates TBCF10839 and TBCF121838: distinct signatures of transcriptome, proteome, metabolome, adherence and pathogenicity despite an almost identical genome sequence. Environ Microbiol 2012; 15:191-210. [PMID: 22882573 DOI: 10.1111/j.1462-2920.2012.02842.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Microevolution of closely related Pseudomonas aeruginosa was compared in the clone TB strains TBCF10839 and TBCF121838 which had been isolated from two unrelated individuals with cystic fibrosis who had acquired clone TB during a local outbreak. Compared with the strain PAO1 reference sequence the two clone TB genomes shared 23 155 nucleotide exchanges, 32 out-of-frame indels in the coding region and another repertoire of replacement and genomic islands such as PAGI-1, PAGI-2, PAGI-5, LESGI-1 and LES-prophage 4. Only TBCF121838 carried a genomic island known from Ralstonia pickettii. Six of the seven strain-specific sequence variations in the core genome were detected in genes affecting motility, biofilm formation or virulence, i.e. non-synonymous nucleotide substitutions in mexS, PA3729, PA5017, mifR, a frameshift mutation in pilF (TBCF121838) and an intragenic deletion in pilQ (TBCF10839). Despite their almost identical genome sequence the two strains differed strongly from each other in transcriptome and metabolome profiles, mucin adherence and phagocytosis assays. TBCF121838 was susceptible to killing by neutrophils, but TBCF10839 could grow in leucocytes. Microevolution in P. aeruginosa apparently can generate novel complex traits by few or even single mutations provided that predisposing mutational events had occurred before in the clonal lineage.
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Affiliation(s)
- Jens Klockgether
- Klinische Forschergruppe, Zentrum Biochemie und Zentrum Kinder- und Jugendmedizin, OE 6710, D-30625 Hannover, Germany.
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Kawakita Y, Taguchi F, Inagaki Y, Toyoda K, Shiraishi T, Ichinose Y. Characterization of each aefR and mexT mutant in Pseudomonas syringae pv. tabaci 6605. Mol Genet Genomics 2012; 287:473-84. [PMID: 22552803 DOI: 10.1007/s00438-012-0693-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Accepted: 04/17/2012] [Indexed: 11/25/2022]
Abstract
To investigate the mechanism of activation of the genes for resistance-nodulation-division (RND) family members MexE, MexF, and OprN for multidrug resistance (MDR), we mutagenized aefR and mexT, the potential regulators of mexEF/oprN transcription in Pseudomonas syringae pv. tabaci 6605 (Pta 6605). AefR is a member of the TetR transcription factors, and is known to be required for production of the quorum-sensing molecules, acyl homoserine lactones (AHL), in P. syringae. Furthermore, we found that AHL-synthesis-defective mutant strains in Pta 6605 showed enhanced expression of mexEF/oprN, and were highly tolerant to antimicrobial compounds such as chloramphenicol. MexT is a LysR-type transcription factor and is known to positively regulate transcription of mexEF/oprN in Pseudomonas aeruginosa. The ∆aefR mutant reduced the amount of growth in in vitro culture, caused the loss of AHL production, reduced the swarming motility, virulence and expression of psyI (AHL synthase) and psyR (AHL transcriptional regulator), and enhanced mexEF/oprN expression and tolerance to chloramphenicol, whereas the ∆mexT mutant retained the ability to produce AHL and did not show remarkable changes in in vitro growth, tolerance to antimicrobial compounds or virulence. Furthermore, unlike P. aeruginosa, the expression of mexEF/oprN is independent of MexT. These results indicate that (1) AefR is a regulator for the quorum-sensing system and MDR, and is required for swarming motility and virulence toward the host tobacco plant, and (2) MexT is not involved in the expression of mexEF/oprN in this bacterium.
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Affiliation(s)
- Yuichiro Kawakita
- Graduate School of Natural Science and Technology, Okayama University, Tsushima-naka 1-1-1, Okayama 700-8530, Japan
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48
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MexT functions as a redox-responsive regulator modulating disulfide stress resistance in Pseudomonas aeruginosa. J Bacteriol 2012; 194:3502-11. [PMID: 22544265 DOI: 10.1128/jb.06632-11] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
MexT is a global LysR transcriptional regulator known to modulate antibiotic resistance and virulence in Pseudomonas aeruginosa. In this study, a novel role for MexT in mediating intrinsic disulfide stress resistance was demonstrated, representing the first identified phenotype associated with inactivation of this regulator in wild-type cells. Disruption of mexT resulted in increased susceptibility to the disulfide stress elicitor diamide [diazenedicarboxylic acid bis(N,N,-di-methylamide)]. This compound is known to elicit a specific stress response via depletion of reduced glutathione and alteration of the cellular redox environment, implicating MexT in redox control. In support of this, MexT-regulated targets, including the MexEF-OprN multidrug efflux system, were induced by subinhibitory concentrations of diamide. A mexF insertion mutant also exhibited increased diamide susceptibility, implicating the MexEF-OprN efflux system in MexT-associated disulfide stress resistance. Purified MexT protein was observed to form an oligomeric complex in the presence of oxidized glutathione, with a calculated redox potential of -189 mV. This value far exceeds the thiol-disulfide redox potential of the bacterial cytoplasm, ensuring that MexT remains reduced under normal physiological conditions. MexT is activated by mutational disruption of the predicted quinone oxidoreductase encoded by mexS. Alterations in the cellular redox state were observed in a mexS mutant (PA14nfxC), supporting a model whereby the perception of MexS-associated redox signals by MexT leads to the induction of the MexEF-OprN efflux system, which, in turn, may mediate disulfide stress resistance via efflux of electrophilic compounds.
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49
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Olivares J, Alvarez-Ortega C, Linares JF, Rojo F, Köhler T, Martínez JL. Overproduction of the multidrug efflux pump MexEF-OprN does not impair Pseudomonas aeruginosa fitness in competition tests, but produces specific changes in bacterial regulatory networks. Environ Microbiol 2012; 14:1968-81. [PMID: 22417660 DOI: 10.1111/j.1462-2920.2012.02727.x] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
It is generally assumed that acquisition of antibiotic resistance leads to non-specific fitness costs. We have tested the alternative hypothesis that acquisition of antibiotic resistance may not always produce a general burden to the microorganisms, as measured in competition tests, but rather lead to specific changes in bacterial physiology. To this end we studied the effect of overproducing the multidrug efflux pump MexEF-OprN on Pseudomonas aeruginosa due to a constitutive activation of MexT, the transcriptional activator of the mexEF-oprN genes. We found that overexpression of MexEF-OprN does not cause a significant decrease in P.aeruginosa fitness in classical competition tests, indicating the absence of a large metabolic burden and that any possible negative effects might be observed only under specific conditions. Transcriptomic analyses revealed that overexpression of MexEF-OprN results in reduced expression of several quorum-sensing regulated genes. We traced back this phenotype to a delay in PQS production due to extrusion of kynurenine, a PQS precursor, through the efflux pump. Type VI secretion was also impaired. A Caenorhabditis elegans model demonstrated that overproduction of MexEF-OprN impairs virulence in P.aeruginosa. This effect was mainly due to the activity of the efflux pump, and not to MexT, despite the fact that the latter regulates Type III and Type VI secretion. Altogether, these data indicate that antibiotic resistance can produce modifications in the bacterial regulatory networks with relevant consequences for the bacterial behaviour in specific ecosystems, including the infected host.
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Affiliation(s)
- Jorge Olivares
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, CSIC, Darwin 3, Cantoblanco, 28049-Madrid, Spain
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Alterations of OprD in carbapenem-intermediate and -susceptible strains of Pseudomonas aeruginosa isolated from patients with bacteremia in a Spanish multicenter study. Antimicrob Agents Chemother 2012; 56:1703-13. [PMID: 22290967 DOI: 10.1128/aac.05451-11] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
We investigated the presence of OprD mutations in 60 strains of metallo-ß-lactamase-negative Pseudomonas aeruginosa intermediately susceptible (IS [n = 12]; MIC = 8 μg/ml) or susceptible (S [n = 48]; MICs ≤ 1 to 4 μg/ml) to imipenem and/or meropenem that were isolated from patients with bacteremia in order to evaluate their impact on carbapenem susceptibility profiles. The presence of mutations in oprD was detected by sequencing analysis. OprD expression was assessed by both outer membrane protein (OMP) analysis and real-time PCR (RT-PCR). Fourteen (23%) isolates had an OprD identical to that of PAO1, and OprD modifications were detected in 46 isolates (77%). Isolates were classified as OprD "full-length types" (T1 [n = 40, including both wild-type OprD and variants showing several polymorphisms]) and OprD "deficient types" (T2 [n = 3 for OprD frameshift mutations] and T3 [n = 17 for premature stop codons in oprD]). RT-PCR showed that 5 OprD type T1 isolates presented reduced transcription of oprD (0.1- to 0.4-fold compared to PAO1), while oprD levels increased more than 2-fold over that seen with PAO1 in 4 OprD type T1 isolates. A total of 50% of the isolates belonging to OprD "deficient types" were susceptible to both carbapenems, and 40% were susceptible to meropenem and intermediately susceptible to imipenem. Only one isolate (5%) within this group was intermediately susceptible to both carbapenems, and one (5%) was susceptible to imipenem and intermediately susceptible to meropenem. We concluded that OprD inactivating mutations in clinical isolates of P. aeruginosa are not restricted only to carbapenem-resistant isolates but are also found in isolates with imipenem or meropenem MICs of only 0.06 to 4 μg/ml.
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