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Vohra M, Kour A, Kalia NP, Kumar M, Sharma S, Jaglan S, Kamath N, Sharma S. A comprehensive review of genomics, transcriptomics, proteomics, and metabolomic insights into the differentiation of Pseudomonas aeruginosa from the planktonic to biofilm state: A multi-omics approach. Int J Biol Macromol 2024; 257:128563. [PMID: 38070800 DOI: 10.1016/j.ijbiomac.2023.128563] [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: 07/20/2023] [Revised: 11/06/2023] [Accepted: 11/30/2023] [Indexed: 01/26/2024]
Abstract
Biofilm formation by Pseudomonas aeruginosa is primarily responsible for chronic wound and lung infections in humans. These infections are persistent owing to the biofilm's high tolerance to antimicrobials and constantly changing environmental factors. Understanding the mechanism governing biofilm formation can help to develop therapeutics explicitly directed against the molecular markers responsible for this process. After numerous years of research, many genes responsible for both in vitro and in vivo biofilm development remain unidentified. However, there is no "all in one" complete in vivo or in vitro biofilm model. Recent findings imply that the shift from planktonic bacteria to biofilms is a complicated and interrelated differentiation process. Research on the applications of omics technologies in P. aeruginosa biofilm development is ongoing, and these approaches hold great promise for expanding our knowledge of the mechanisms of biofilm formation. This review discusses the different factors that affect biofilm formation and compares P. aeruginosa biofilm formation using the omics approaches targeting essential biological macromolecules, such as DNA, RNA, Protein, and metabolome. Furthermore, we have outlined the application of currently available omics tools, such as genomics, proteomics, metabolomics, transcriptomics, and integrated multi-omics methodologies, to understand the differential gene expression (biofilm vs. planktonic bacteria) of P. aeruginosa biofilms.
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Affiliation(s)
- Mustafa Vohra
- Department of Medical Laboratory Science, Lovely Professional University, Punjab 144411, India; Department of Microbiology, Shri Vinoba Bhave Civil Hospital, Silvassa 396230, India
| | - Avleen Kour
- Department of Medical Laboratory Science, Lovely Professional University, Punjab 144411, India
| | - Nitin Pal Kalia
- Department of Biological Sciences (Pharmacology & Toxicology), National Institute of Pharmaceutical Education and Research (NIPER), Balanagar, Hyderabad, Telangana 500037, India
| | - Manoj Kumar
- Maternal and Child Health Program, Research Department, Sidra Medicine, Doha 122104, Qatar
| | - Sarika Sharma
- Department of Sponsored Research, Division of Research & Development, Lovely Professional University, India
| | - Sundeep Jaglan
- Fermentation & Microbial Biotechnology Division, CSIR-Indian Institute of Integrative Medicine, Jammu 180016, J&K, India
| | - Narayan Kamath
- Department of Microbiology, Shri Vinoba Bhave Civil Hospital, Silvassa 396230, India; Department of Microbiology, NAMO Medical Education and Research Institute, Silvassa 396230, India
| | - Sandeep Sharma
- Department of Medical Laboratory Science, Lovely Professional University, Punjab 144411, India.
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Nazeer RR, Wang M, Welch M. More than just a gel: the extracellular matrixome of Pseudomonas aeruginosa. Front Mol Biosci 2023; 10:1307857. [PMID: 38028553 PMCID: PMC10679415 DOI: 10.3389/fmolb.2023.1307857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Accepted: 10/31/2023] [Indexed: 12/01/2023] Open
Abstract
Armed with an arsenal of protein secretion systems, antibiotic efflux pumps, and the occasional proclivity for explosive self-destruction, Pseudomonas aeruginosa has become a model for the study of bacterial pathogenesis and biofilm formation. There is accruing evidence to suggest that the biofilm matrix-the bioglue that holds the structure together-acts not only in a structural capacity, but is also a molecular "net" whose function is to capture and retain certain secreted products (including proteins and small molecules). In this perspective, we argue that the biofilm matrixome is a distinct extracellular compartment, and one that is differentiated from the bulk secretome. Some of the points we raise are deliberately speculative, but are becoming increasingly accessible to experimental investigation.
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Affiliation(s)
| | | | - Martin Welch
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
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3
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Transcriptional Profiling of Pseudomonas aeruginosa Infections. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1386:303-323. [DOI: 10.1007/978-3-031-08491-1_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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4
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Metabolic Heterogeneity and Cross-Feeding in Bacterial Multicellular Systems. Trends Microbiol 2020; 28:732-743. [PMID: 32781027 DOI: 10.1016/j.tim.2020.03.008] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 03/25/2020] [Indexed: 01/19/2023]
Abstract
Cells in assemblages differentiate and perform distinct roles. Though many pathways of differentiation are understood at the molecular level in multicellular eukaryotes, the elucidation of similar processes in bacterial assemblages is recent and ongoing. Here, we discuss examples of bacterial differentiation, focusing on cases in which distinct metabolisms coexist and those that exhibit cross-feeding, with one subpopulation producing substrates that are metabolized by a second subpopulation. We describe several studies of single-species systems, then segue to studies of multispecies metabolic heterogeneity and cross-feeding in the clinical setting. Many of the studies described exemplify the application of new techniques and modeling approaches that provide insights into metabolic interactions relevant for bacterial growth outside the laboratory.
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Schinner S, Engelhardt F, Preusse M, Thöming JG, Tomasch J, Häussler S. Genetic determinants of Pseudomonas aeruginosa fitness during biofilm growth. Biofilm 2020; 2:100023. [PMID: 33447809 PMCID: PMC7798452 DOI: 10.1016/j.bioflm.2020.100023] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2019] [Revised: 03/19/2020] [Accepted: 03/20/2020] [Indexed: 02/06/2023] Open
Abstract
Pseudomonas aeruginosa is an environmental bacterium and an opportunistic human pathogen. It is also a well-established model organism to study bacterial adaptation to stressful conditions, such as those encountered during an infection process in the human host. Advancing knowledge on P. aeruginosa adaptation to biofilm growth conditions is bound to reveal novel strategies and targets for the treatment of chronic biofilm-associated infections. Here, we generated transposon insertion libraries in three P. aeruginosa strain backgrounds and determined the relative frequency of each insertion following biofilm growth using transposon sequencing. We demonstrate that in general the SOS response, several tRNA modifying enzymes as well as adaptation to microaerophilic growth conditions play a key role in bacterial survival under biofilm growth conditions. On the other hand, presence of genes involved in motility and PQS signaling were less important during biofilm growth. Several mutants exhibiting transposon insertions in genes detected in our screen were validated for their biofilm growth capabilities and biofilm specific transcriptional responses using independently generated transposon mutants. Our results provide new insights into P. aeruginosa adaptation to biofilm growth conditions. The detection of previously unknown determinants of biofilm survival supports the use of transposon insertion sequencing as a global genomic technology for understanding the establishment of difficult to treat biofilm-associated infections.
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Affiliation(s)
- Silvia Schinner
- Department of Molecular Bacteriology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Florian Engelhardt
- Department of Molecular Bacteriology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Matthias Preusse
- Department of Molecular Bacteriology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Janne Gesine Thöming
- Institute of Molecular Bacteriology, TWINCORE Centre for Experimental and Clinical Infection Research, Hannover, Germany.,Department of Clinical Microbiology, Copenhagen University Hospital - Rigshospitalet, Copenhagen, Denmark
| | - Jürgen Tomasch
- Department of Molecular Bacteriology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Susanne Häussler
- Department of Molecular Bacteriology, Helmholtz Centre for Infection Research, Braunschweig, Germany.,Institute of Molecular Bacteriology, TWINCORE Centre for Experimental and Clinical Infection Research, Hannover, Germany.,Department of Clinical Microbiology, Copenhagen University Hospital - Rigshospitalet, Copenhagen, Denmark.,Cluster of Excellence RESIST (EXC 2155), Hannover Medical School, Hannover, Germany
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6
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Thöming JG, Tomasch J, Preusse M, Koska M, Grahl N, Pohl S, Willger SD, Kaever V, Müsken M, Häussler S. Parallel evolutionary paths to produce more than one Pseudomonas aeruginosa biofilm phenotype. NPJ Biofilms Microbiomes 2020; 6:2. [PMID: 31934344 PMCID: PMC6954232 DOI: 10.1038/s41522-019-0113-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 12/16/2019] [Indexed: 01/28/2023] Open
Abstract
Studying parallel evolution of similar traits in independent within-species lineages provides an opportunity to address evolutionary predictability of molecular changes underlying adaptation. In this study, we monitored biofilm forming capabilities, motility, and virulence phenotypes of a plethora of phylogenetically diverse clinical isolates of the opportunistic pathogen Pseudomonas aeruginosa. We also recorded biofilm-specific and planktonic transcriptional responses. We found that P. aeruginosa isolates could be stratified based on the production of distinct organismal traits. Three major biofilm phenotypes, which shared motility and virulence phenotypes, were produced repeatedly in several isolates, indicating that the phenotypes evolved via parallel or convergent evolution. Of note, while we found a restricted general response to the biofilm environment, the individual groups of biofilm phenotypes reproduced biofilm transcriptional profiles that included the expression of well-known biofilm features, such as surface adhesive structures and extracellular matrix components. Our results provide insights into distinct ways to make a biofilm and indicate that genetic adaptations can modulate multiple pathways for biofilm development that are followed by several independent clinical isolates. Uncovering core regulatory pathways that drive biofilm-associated growth and tolerance towards environmental stressors promises to give clues to host and environmental interactions and could provide useful targets for new clinical interventions.
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Affiliation(s)
- Janne G. Thöming
- Institute for Molecular Bacteriology, TWINCORE, Centre for Experimental and Clinical Infection Research, Hannover, Germany
- Department of Clinical Microbiology, Copenhagen University Hospital – Rigshospitalet, Copenhagen, Denmark
| | - Jürgen Tomasch
- Department of Molecular Bacteriology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Matthias Preusse
- Department of Molecular Bacteriology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Michal Koska
- Institute for Molecular Bacteriology, TWINCORE, Centre for Experimental and Clinical Infection Research, Hannover, Germany
| | - Nora Grahl
- Institute for Molecular Bacteriology, TWINCORE, Centre for Experimental and Clinical Infection Research, Hannover, Germany
- Department of Molecular Bacteriology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Sarah Pohl
- Institute for Molecular Bacteriology, TWINCORE, Centre for Experimental and Clinical Infection Research, Hannover, Germany
- Department of Molecular Bacteriology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Sven D. Willger
- Institute for Molecular Bacteriology, TWINCORE, Centre for Experimental and Clinical Infection Research, Hannover, Germany
- Department of Molecular Bacteriology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Volkhard Kaever
- Research Core Unit Metabolomics and Institute of Pharmacology, Hannover Medical School, Hannover, Germany
| | - Mathias Müsken
- Institute for Molecular Bacteriology, TWINCORE, Centre for Experimental and Clinical Infection Research, Hannover, Germany
- Department of Molecular Bacteriology, Helmholtz Centre for Infection Research, Braunschweig, Germany
- Central Facility for Microscopy, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Susanne Häussler
- Institute for Molecular Bacteriology, TWINCORE, Centre for Experimental and Clinical Infection Research, Hannover, Germany
- Department of Clinical Microbiology, Copenhagen University Hospital – Rigshospitalet, Copenhagen, Denmark
- Department of Molecular Bacteriology, Helmholtz Centre for Infection Research, Braunschweig, Germany
- Cluster of Excellence RESIST (EXC 2155), Hannover Medical School, Hannover, Germany
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Erdmann J, Thöming JG, Pohl S, Pich A, Lenz C, Häussler S. The Core Proteome of Biofilm-Grown Clinical Pseudomonas aeruginosa Isolates. Cells 2019; 8:E1129. [PMID: 31547513 PMCID: PMC6829490 DOI: 10.3390/cells8101129] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 09/18/2019] [Accepted: 09/19/2019] [Indexed: 12/13/2022] Open
Abstract
Comparative genomics has greatly facilitated the identification of shared as well as unique features among individual cells or tissues, and thus offers the potential to find disease markers. While proteomics is recognized for its potential to generate quantitative maps of protein expression, comparative proteomics in bacteria has been largely restricted to the comparison of single cell lines or mutant strains. In this study, we used a data independent acquisition (DIA) technique, which enables global protein quantification of large sample cohorts, to record the proteome profiles of overall 27 whole genome sequenced and transcriptionally profiled clinical isolates of the opportunistic pathogen Pseudomonas aeruginosa. Analysis of the proteome profiles across the 27 clinical isolates grown under planktonic and biofilm growth conditions led to the identification of a core biofilm-associated protein profile. Furthermore, we found that protein-to-mRNA ratios between different P. aeruginosa strains are well correlated, indicating conserved patterns of post-transcriptional regulation. Uncovering core regulatory pathways, which drive biofilm formation and associated antibiotic tolerance in bacterial pathogens, promise to give clues to interactions between bacterial species and their environment and could provide useful targets for new clinical interventions to combat biofilm-associated infections.
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Affiliation(s)
- Jelena Erdmann
- Institute for Molecular Bacteriology, TWINCORE GmbH, Centre for Experimental and Clinical Infection Research, a joint venture of the Hannover Medical School and the Helmholtz Centre for Infection Research, Hannover 30625, Germany.
- Research Core Unit Proteomics and Institute of Toxicology, Hannover Medical School, Hannover 30625, Germany.
| | - Janne G Thöming
- Institute for Molecular Bacteriology, TWINCORE GmbH, Centre for Experimental and Clinical Infection Research, a joint venture of the Hannover Medical School and the Helmholtz Centre for Infection Research, Hannover 30625, Germany.
| | - Sarah Pohl
- Institute for Molecular Bacteriology, TWINCORE GmbH, Centre for Experimental and Clinical Infection Research, a joint venture of the Hannover Medical School and the Helmholtz Centre for Infection Research, Hannover 30625, Germany.
- Department of Molecular Bacteriology, Helmholtz Center for Infection Research, Braunschweig 38124, Germany.
| | - Andreas Pich
- Research Core Unit Proteomics and Institute of Toxicology, Hannover Medical School, Hannover 30625, Germany.
| | - Christof Lenz
- Institute of Clinical Chemistry, Bioanalytics, University Medical Center Göttingen, Göttingen 37075, Germany.
- Max Planck Institute for Biophysical Chemistry, Bioanalytical Mass Spectrometry, Göttingen 37077, Germany.
| | - Susanne Häussler
- Institute for Molecular Bacteriology, TWINCORE GmbH, Centre for Experimental and Clinical Infection Research, a joint venture of the Hannover Medical School and the Helmholtz Centre for Infection Research, Hannover 30625, Germany.
- Department of Molecular Bacteriology, Helmholtz Center for Infection Research, Braunschweig 38124, Germany.
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8
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Chang CY. Surface Sensing for Biofilm Formation in Pseudomonas aeruginosa. Front Microbiol 2018; 8:2671. [PMID: 29375533 PMCID: PMC5767216 DOI: 10.3389/fmicb.2017.02671] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Accepted: 12/21/2017] [Indexed: 11/13/2022] Open
Abstract
Aggregating and forming biofilms on biotic or abiotic surfaces are ubiquitous bacterial behaviors under various conditions. In clinical settings, persistent presence of biofilms increases the risks of healthcare-associated infections and imposes huge healthcare and economic burdens. Bacteria within biofilms are protected from external damage and attacks from the host immune system and can exchange genomic information including antibiotic-resistance genes. Dispersed bacterial cells from attached biofilms on medical devices or host tissues may also serve as the origin of further infections. Understanding how bacteria develop biofilms is pertinent to tackle biofilm-associated infections and transmission. Biofilms have been suggested as a continuum of growth modes for adapting to different environments, initiating from bacterial cells sensing their attachment to a surface and then switching cellular physiological status for mature biofilm development. It is crucial to understand bacterial gene regulatory networks and decision-making processes for biofilm formation upon initial surface attachment. Pseudomonas aeruginosa is one of the model microorganisms for studying bacterial population behaviors. Several hypotheses and studies have suggested that extracellular macromolecules and appendages play important roles in bacterial responses to the surface attachment. Here, I review recent studies on potential molecular mechanisms and signal transduction pathways for P. aeruginosa surface sensing.
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Affiliation(s)
- Chien-Yi Chang
- School of Chemistry and Biosciences, University of Bradford, Bradford, United Kingdom
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9
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Transcriptomic Analyses Elucidate Adaptive Differences of Closely Related Strains of Pseudomonas aeruginosa in Fuel. Appl Environ Microbiol 2017; 83:AEM.03249-16. [PMID: 28314727 DOI: 10.1128/aem.03249-16] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 03/06/2017] [Indexed: 02/03/2023] Open
Abstract
Pseudomonas aeruginosa can utilize hydrocarbons, but different strains have various degrees of adaptation despite their highly conserved genome. P. aeruginosa ATCC 33988 is highly adapted to hydrocarbons, while P. aeruginosa strain PAO1, a human pathogen, is less adapted and degrades jet fuel at a lower rate than does ATCC 33988. We investigated fuel-specific transcriptomic differences between these strains in order to ascertain the underlying mechanisms utilized by the adapted strain to proliferate in fuel. During growth in fuel, the genes related to alkane degradation, heat shock response, membrane proteins, efflux pumps, and several novel genes were upregulated in ATCC 33988. Overexpression of alk genes in PAO1 provided some improvement in growth, but it was not as robust as that of ATCC 33988, suggesting the role of other genes in adaptation. Expression of the function unknown gene PA5359 from ATCC 33988 in PAO1 increased the growth in fuel. Bioinformatic analysis revealed that PA5359 is a predicted lipoprotein with a conserved Yx(FWY)xxD motif, which is shared among bacterial adhesins. Overexpression of the putative resistance-nodulation-division (RND) efflux pump PA3521 to PA3523 increased the growth of the ATCC 33988 strain, suggesting a possible role in fuel tolerance. Interestingly, the PAO1 strain cannot utilize n-C8 and n-C10 The expression of green fluorescent protein (GFP) under the control of alkB promoters confirmed that alk gene promoter polymorphism affects the expression of alk genes. Promoter fusion assays further confirmed that the regulation of alk genes was different in the two strains. Protein sequence analysis showed low amino acid differences for many of the upregulated genes, further supporting transcriptional control as the main mechanism for enhanced adaptation.IMPORTANCE These results support that specific signal transduction, gene regulation, and coordination of multiple biological responses are required to improve the survival, growth, and metabolism of fuel in adapted strains. This study provides new insight into the mechanistic differences between strains and helpful information that may be applied in the improvement of bacterial strains for resistance to biotic and abiotic factors encountered during bioremediation and industrial biotechnological processes.
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10
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Multi-omics analysis of niche specificity provides new insights into ecological adaptation in bacteria. ISME JOURNAL 2016; 10:2072-5. [PMID: 26859773 DOI: 10.1038/ismej.2015.251] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 11/30/2015] [Indexed: 12/13/2022]
Abstract
Different lifestyles, ranging from a saprophyte to a pathogen, have been reported in bacteria of one species. Here, we performed genome-wide survey of the ecological adaptation in four Burkholderia seminalis strains, distinguished by their origin as part of the saprophytic microbial community of soil or water but also including human and plant pathogens. The results indicated that each strain is separated from the others by increased fitness in medium simulating its original niche corresponding to the difference between strains in metabolic capacities. Furthermore, strain-specific metabolism and niche survival was generally linked with genomic variants and niche-dependent differential expression of the corresponding genes. In particular, the importance of iron, trehalose and d-arabitol utilization was highlighted by the involvement of DNA-methylation and horizontal gene transfer in niche-adapted regulation of the corresponding operons based on the integrated analysis of our multi-omics data. Overall, our results provided insights of niche-specific adaptation in bacteria.
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Crousilles A, Maunders E, Bartlett S, Fan C, Ukor EF, Abdelhamid Y, Baker Y, Floto A, Spring DR, Welch M. Which microbial factors really are important in Pseudomonas aeruginosa infections? Future Microbiol 2015; 10:1825-36. [DOI: 10.2217/fmb.15.100] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Over the last two decades, tens of millions of dollars have been invested in understanding virulence in the human pathogen, Pseudomonas aeruginosa. However, the top ‘hits’ obtained in a recent TnSeq analysis aimed at identifying those genes that are conditionally essential for infection did not include most of the known virulence factors identified in these earlier studies. Instead, it seems that P. aeruginosa faces metabolic challenges in vivo, and unless it can overcome these, it fails to thrive and is cleared from the host. In this review, we look at the kinds of metabolic pathways that the pathogen seems to find essential, and comment on how this knowledge might be therapeutically exploited.
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Affiliation(s)
- Audrey Crousilles
- Department of Biochemistry (Hopkins Building), Tennis Court Road, Cambridge, CB2 1QW, UK
| | - Eve Maunders
- Department of Biochemistry (Hopkins Building), Tennis Court Road, Cambridge, CB2 1QW, UK
| | - Sean Bartlett
- Department of Chemistry, Lensfield Road, Cambridge, CB2 1EW, UK
| | - Catherine Fan
- Department of Biochemistry (Hopkins Building), Tennis Court Road, Cambridge, CB2 1QW, UK
| | - Emem-Fong Ukor
- Department of Respiratory Medicine, Cambridge Biomedical Campus, Wellcome Trust/MRC Building, Hills Road, Cambridge, CB2 0XY, UK
| | - Yassmin Abdelhamid
- Department of Biochemistry (Hopkins Building), Tennis Court Road, Cambridge, CB2 1QW, UK
| | - Ysobel Baker
- Department of Chemistry, Lensfield Road, Cambridge, CB2 1EW, UK
| | - Andres Floto
- Department of Respiratory Medicine, Cambridge Biomedical Campus, Wellcome Trust/MRC Building, Hills Road, Cambridge, CB2 0XY, UK
| | - David R Spring
- Department of Chemistry, Lensfield Road, Cambridge, CB2 1EW, UK
| | - Martin Welch
- Department of Biochemistry (Hopkins Building), Tennis Court Road, Cambridge, CB2 1QW, UK
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Vital-Lopez FG, Reifman J, Wallqvist A. Biofilm Formation Mechanisms of Pseudomonas aeruginosa Predicted via Genome-Scale Kinetic Models of Bacterial Metabolism. PLoS Comput Biol 2015; 11:e1004452. [PMID: 26431398 PMCID: PMC4592021 DOI: 10.1371/journal.pcbi.1004452] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 07/14/2015] [Indexed: 12/28/2022] Open
Abstract
A hallmark of Pseudomonas aeruginosa is its ability to establish biofilm-based infections that are difficult to eradicate. Biofilms are less susceptible to host inflammatory and immune responses and have higher antibiotic tolerance than free-living planktonic cells. Developing treatments against biofilms requires an understanding of bacterial biofilm-specific physiological traits. Research efforts have started to elucidate the intricate mechanisms underlying biofilm development. However, many aspects of these mechanisms are still poorly understood. Here, we addressed questions regarding biofilm metabolism using a genome-scale kinetic model of the P. aeruginosa metabolic network and gene expression profiles. Specifically, we computed metabolite concentration differences between known mutants with altered biofilm formation and the wild-type strain to predict drug targets against P. aeruginosa biofilms. We also simulated the altered metabolism driven by gene expression changes between biofilm and stationary growth-phase planktonic cultures. Our analysis suggests that the synthesis of important biofilm-related molecules, such as the quorum-sensing molecule Pseudomonas quinolone signal and the exopolysaccharide Psl, is regulated not only through the expression of genes in their own synthesis pathway, but also through the biofilm-specific expression of genes in pathways competing for precursors to these molecules. Finally, we investigated why mutants defective in anthranilate degradation have an impaired ability to form biofilms. Alternative to a previous hypothesis that this biofilm reduction is caused by a decrease in energy production, we proposed that the dysregulation of the synthesis of secondary metabolites derived from anthranilate and chorismate is what impaired the biofilms of these mutants. Notably, these insights generated through our kinetic model-based approach are not accessible from previous constraint-based model analyses of P. aeruginosa biofilm metabolism. Our simulation results showed that plausible, non-intuitive explanations of difficult-to-interpret experimental observations could be generated by integrating genome-scale kinetic models with gene expression profiles.
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Affiliation(s)
- Francisco G. Vital-Lopez
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, U.S. Army Medical Research and Materiel Command, Fort Detrick, Maryland, United States of America
| | - Jaques Reifman
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, U.S. Army Medical Research and Materiel Command, Fort Detrick, Maryland, United States of America
- * E-mail:
| | - Anders Wallqvist
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, U.S. Army Medical Research and Materiel Command, Fort Detrick, Maryland, United States of America
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Contribution of stress responses to antibiotic tolerance in Pseudomonas aeruginosa biofilms. Antimicrob Agents Chemother 2015; 59:3838-47. [PMID: 25870065 DOI: 10.1128/aac.00433-15] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Accepted: 04/07/2015] [Indexed: 11/20/2022] Open
Abstract
Enhanced tolerance of biofilm-associated bacteria to antibiotic treatments is likely due to a combination of factors, including changes in cell physiology as bacteria adapt to biofilm growth and the inherent physiological heterogeneity of biofilm bacteria. In this study, a transcriptomics approach was used to identify genes differentially expressed during biofilm growth of Pseudomonas aeruginosa. These genes were tested for statistically significant overlap, with independently compiled gene lists corresponding to stress responses and other putative antibiotic-protective mechanisms. Among the gene groups tested were those associated with biofilm response to tobramycin or ciprofloxacin, drug efflux pumps, acyl homoserine lactone quorum sensing, osmotic shock, heat shock, hypoxia stress, and stationary-phase growth. Regulons associated with Anr-mediated hypoxia stress, RpoS-regulated stationary-phase growth, and osmotic stress were significantly enriched in the set of genes induced in the biofilm. Mutant strains deficient in rpoS, relA and spoT, or anr were cultured in biofilms and challenged with ciprofloxacin and tobramycin. When challenged with ciprofloxacin, the mutant strain biofilms had 2.4- to 2.9-log reductions in viable cells compared to a 0.9-log reduction of the wild-type strain. Interestingly, none of the mutants exhibited a statistically significant alteration in tobramycin susceptibility compared to that with the wild-type biofilm. These results are consistent with a model in which multiple genes controlled by overlapping starvation or stress responses contribute to the protection of a P. aeruginosa biofilm from ciprofloxacin. A distinct and as yet undiscovered mechanism protects the biofilm bacteria from tobramycin.
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Mep72, a metzincin protease that is preferentially secreted by biofilms of Pseudomonas aeruginosa. J Bacteriol 2014; 197:762-73. [PMID: 25488299 PMCID: PMC4334185 DOI: 10.1128/jb.02404-14] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
In this work, we compared the profile of proteins secreted by planktonic and biofilm cultures of Pseudomonas aeruginosa using two-dimensional difference gel electrophoresis (2D-DiGE). This revealed that a novel metzincin protease, Mep72, was secreted during biofilm growth. Subsequent Western blotting and reverse transcription-PCR (RT-PCR) analyses demonstrated that Mep72 was expressed only during biofilm growth. Mep72 has a tridomain structure comprised of a metzincin protease-like domain and two tandem carbohydrate-binding domains. Unlike the only other metzincin (alkaline protease; AprA) in P. aeruginosa, Mep72 is secreted through the type II pathway and undergoes processing during export. During this processing, the metzincin domain is liberated from the carbohydrate-binding domains. This processing may be self-catalyzed, since purified Mep72 autodegraded in vitro. This autodegradation was retarded in the presence of alginate (an extracellular matrix component of many P. aeruginosa biofilms). The expression of full-length mep72 in Escherichia coli was toxic. However, this toxicity could be alleviated by coexpression of mep72 with the adjacent gene, bamI. Mep72 and BamI were found to form a protein-protein complex in vitro. 2D-DiGE revealed that the electrophoretic mobility of several discrete protein spots was altered in the biofilm secretome of an mep72 mutant, including type III secretion proteins (PopD, PcrV, and ExoS) and a flagellum-associated protein (FliD). Mep72 was found to bind directly to ExoS and PcrV and to affect the processing of these proteins in the biofilm secretome. We conclude that Mep72 is a secreted biofilm-specific regulator that affects the processing of a very specific subset of virulence factors.
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Zhang XX, Ritchie SR, Rainey PB. Urocanate as a potential signaling molecule for bacterial recognition of eukaryotic hosts. Cell Mol Life Sci 2014; 71:541-7. [PMID: 24305948 PMCID: PMC11113655 DOI: 10.1007/s00018-013-1527-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Revised: 10/29/2013] [Accepted: 11/18/2013] [Indexed: 12/24/2022]
Abstract
Host recognition is the crucial first step in infectious disease pathogenesis. Recognition allows pathogenic bacteria to identify suitable niches and deploy appropriate phenotypes for successful colonization and immune evasion. However, the mechanisms underlying host recognition remain largely unknown. Mounting evidence suggests that urocanate-an intermediate of the histidine degradation pathway-accumulates in tissues, such as skin, and acts as a molecule that promotes bacterial infection via molecular interaction with the bacterial regulatory protein HutC. In Gram-negative bacteria, HutC has long been known as a transcriptional repressor of hut genes for the utilization of histidine (and urocanate) as sources of carbon and nitrogen. Recent work on the opportunistic human pathogen Pseudomonas aeruginosa and zoonotic pathogen Brucella abortus shows that urocanate, in conjunction with HutC, plays a significant role in the global control of cellular metabolism, cell motility, and expression of virulence factors. We suggest that in addition to being a valuable source of carbon and nitrogen, urocanate may be central to the elicitation of bacterial pathogenesis.
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Affiliation(s)
- Xue-Xian Zhang
- Institute of Natural and Mathematical Sciences, Massey University at Albany, Auckland, 0745, New Zealand,
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Costaglioli P, Barthe C, Claverol S, Brözel VS, Perrot M, Crouzet M, Bonneu M, Garbay B, Vilain S. Evidence for the involvement of the anthranilate degradation pathway in Pseudomonas aeruginosa biofilm formation. Microbiologyopen 2012; 1:326-39. [PMID: 23170231 PMCID: PMC3496976 DOI: 10.1002/mbo3.33] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2012] [Revised: 06/21/2012] [Accepted: 07/02/2012] [Indexed: 12/03/2022] Open
Abstract
Bacterial biofilms are complex cell communities found attached to surfaces and surrounded by an extracellular matrix composed of exopolysaccharides, DNA, and proteins. We investigated the whole-genome expression profile of Pseudomonas aeruginosa sessile cells (SCs) present in biofilms developed on a glass wool substratum. The transcriptome and proteome of SCs were compared with those of planktonic cell cultures. Principal component analysis revealed a biofilm-specific gene expression profile. Our study highlighted the overexpression of genes controlling the anthranilate degradation pathway in the SCs grown on glass wool for 24 h. In this condition, the metabolic pathway that uses anthranilate for Pseudomonas quinolone signal production was not activated, which suggested that anthranilate was primarily being consumed for energy metabolism. Transposon mutants defective for anthranilate degradation were analyzed in a simple assay of biofilm formation. The phenotypic analyses confirmed that P. aeruginosa biofilm formation partially depended on the activity of the anthranilate degradation pathway. This work points to a new feature concerning anthranilate metabolism in P. aeruginosa SCs.
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Affiliation(s)
- Patricia Costaglioli
- Biotechnologie des Protéines Recombinantes à Visée Santé, University Bordeaux EA4135, F-33000, Bordeaux, France
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Gerth ML, Ferla MP, Rainey PB. The origin and ecological significance of multiple branches for histidine utilization in Pseudomonas aeruginosa PAO1. Environ Microbiol 2012; 14:1929-40. [PMID: 22225844 DOI: 10.1111/j.1462-2920.2011.02691.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Pseudomonas proliferate in a wide spectrum of harsh and variable environments. In many of these environments, amino acids, such as histidine, are a valuable source of carbon, nitrogen and energy. Here, we demonstrate that the histidine uptake and utilization (hut) pathway of Pseudomonas aeruginosa PAO1 contains two branches from the intermediate formiminoglutamate to the product glutamate. Genetic analysis revealed that the four-step route is dispensable as long as the five-step route is present (and vice versa). Mutants with deletions of either the four-step (HutE) or five-step (HutFG) branches were competed against each other and the wild-type strain to test the hypothesis of ecological redundancy; that is, that the presence of two pathways confers no benefit beyond that delivered by the individual pathways. Fitness assays performed under several environmental conditions led us to reject this hypothesis; the four-step pathway can provide an advantage when histidine is the sole carbon source. An IclR-type regulator (HutR) was identified that regulates the four-step pathway. Comparison of sequenced genomes revealed that P.aeruginosa strains and P.fluorescens Pf-5 have branched hut pathways. Phylogenetic analyses suggests that the gene encoding formiminoglutamase (hutE) was acquired by horizontal gene transfer from a Ralstonia-like ancestor. Potential barriers to inter-species transfer of the hutRE module were explored by transferring it from P.aeruginosa PAO1 to P.fluorescens SBW25. Transfer of the operon conferred the ability to utilize histidine via the four-step pathway in a single step, but the fitness cost of acquiring this new operon was found to be environment dependent.
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Affiliation(s)
- Monica L Gerth
- New Zealand Institute for Advanced Study, Massey University, Auckland, New Zealand.
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Folsom JP, Richards L, Pitts B, Roe F, Ehrlich GD, Parker A, Mazurie A, Stewart PS. Physiology of Pseudomonas aeruginosa in biofilms as revealed by transcriptome analysis. BMC Microbiol 2010; 10:294. [PMID: 21083928 PMCID: PMC2998477 DOI: 10.1186/1471-2180-10-294] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2010] [Accepted: 11/17/2010] [Indexed: 11/23/2022] Open
Abstract
Background Transcriptome analysis was applied to characterize the physiological activities of Pseudomonas aeruginosa grown for three days in drip-flow biofilm reactors. Conventional applications of transcriptional profiling often compare two paired data sets that differ in a single experimentally controlled variable. In contrast this study obtained the transcriptome of a single biofilm state, ranked transcript signals to make the priorities of the population manifest, and compared ranki ngs for a priori identified physiological marker genes between the biofilm and published data sets. Results Biofilms tolerated exposure to antibiotics, harbored steep oxygen concentration gradients, and exhibited stratified and heterogeneous spatial patterns of protein synthetic activity. Transcriptional profiling was performed and the signal intensity of each transcript was ranked to gain insight into the physiological state of the biofilm population. Similar rankings were obtained from data sets published in the GEO database http://www.ncbi.nlm.nih.gov/geo. By comparing the rank of genes selected as markers for particular physiological activities between the biofilm and comparator data sets, it was possible to infer qualitative features of the physiological state of the biofilm bacteria. These biofilms appeared, from their transcriptome, to be glucose nourished, iron replete, oxygen limited, and growing slowly or exhibiting stationary phase character. Genes associated with elaboration of type IV pili were strongly expressed in the biofilm. The biofilm population did not indicate oxidative stress, homoserine lactone mediated quorum sensing, or activation of efflux pumps. Using correlations with transcript ranks, the average specific growth rate of biofilm cells was estimated to be 0.08 h-1. Conclusions Collectively these data underscore the oxygen-limited, slow-growing nature of the biofilm population and are consistent with antimicrobial tolerance due to low metabolic activity.
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Affiliation(s)
- James P Folsom
- Center for Biofilm Engineering and Department of Chemical and Biological Engineering, PO Box 173980, Montana State University-Bozeman, Bozeman, Montana 59717-3980, USA
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