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Conaway A, Todorovic I, Mould DL, Hogan DA. Loss of LasR function leads to decreased repression of Pseudomonas aeruginosa PhoB activity at physiological phosphate concentrations. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.27.586856. [PMID: 38585852 PMCID: PMC10996656 DOI: 10.1101/2024.03.27.586856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
While the Pseudomonas aeruginosa LasR transcription factor plays a role in quorum sensing (QS) across phylogenetically-distinct lineages, isolates with loss-of-function mutations in lasR (LasR- strains) are commonly found in diverse settings including infections where they are associated with worse clinical outcomes. In LasR- strains, the transcription factor RhlR, which is controlled by LasR, can be alternately activated in low inorganic phosphate (Pi) concentrations via the two-component system PhoR-PhoB. Here, we demonstrate a new link between LasR and PhoB in which the absence of LasR increases PhoB activity at physiological Pi concentrations and raises the Pi concentration necessary for PhoB inhibition. PhoB activity was also less repressed by Pi in mutants lacking different QS regulators (RhlR and PqsR) and in mutants lacking genes required for the production of QS-regulated phenazines suggesting that decreased phenazine production was one reason for decreased PhoB repression by Pi in LasR- strains. In addition, the CbrA-CbrB two-component system, which is elevated in LasR- strains, was necessary for reduced PhoB repression by Pi and a Δcrc mutant, which lacks the CbrA-CbrB-controlled translational repressor, activated PhoB at higher Pi concentrations than the wild type. The ΔlasR mutant had a PhoB-dependent growth advantage in a medium with no added Pi and increased virulence-determinant gene expression in a medium with physiological Pi, in part through reactivation of QS. This work suggests PhoB activity may contribute to the virulence of LasR- P. aeruginosa and subsequent clinical outcomes.
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In Vivo Role of Two-Component Regulatory Systems in Models of Urinary Tract Infections. Pathogens 2023; 12:pathogens12010119. [PMID: 36678467 PMCID: PMC9861413 DOI: 10.3390/pathogens12010119] [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: 11/24/2022] [Revised: 12/23/2022] [Accepted: 01/08/2023] [Indexed: 01/12/2023] Open
Abstract
Two-component signaling systems (TCSs) are finely regulated mechanisms by which bacteria adapt to environmental conditions by modifying the expression of target genes. In bacterial pathogenesis, TCSs play important roles in modulating adhesion to mucosal surfaces, resistance to antibiotics, and metabolic adaptation. In the context of urinary tract infections (UTI), one of the most common types infections causing significant health problems worldwide, uropathogens use TCSs for adaptation, survival, and establishment of pathogenicity. For example, uropathogens can exploit TCSs to survive inside bladder epithelial cells, sense osmolar variations in urine, promote their ascension along the urinary tract or even produce lytic enzymes resulting in exfoliation of the urothelium. Despite the usefulness of studying the function of TCSs in in vitro experimental models, it is of primary necessity to study bacterial gene regulation also in the context of host niches, each displaying its own biological, chemical, and physical features. In light of this, the aim of this review is to provide a concise description of several bacterial TCSs, whose activity has been described in mouse models of UTI.
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Cangui-Panchi SP, Ñacato-Toapanta AL, Enríquez-Martínez LJ, Salinas-Delgado GA, Reyes J, Garzon-Chavez D, Machado A. Battle royale: Immune response on biofilms – host-pathogen interactions. CURRENT RESEARCH IN IMMUNOLOGY 2023; 4:100057. [PMID: 37025390 PMCID: PMC10070391 DOI: 10.1016/j.crimmu.2023.100057] [Citation(s) in RCA: 22] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 03/08/2023] [Accepted: 03/20/2023] [Indexed: 03/29/2023] Open
Abstract
The research interest of the scientific community in biofilm-forming microorganisms is growing due to the problems caused by their infections affecting humans and animals, mainly because of the difficulty of the host immune system in eradicating these microbial complex communities and the increasing antimicrobial resistance rates worldwide. This review describes the virulence factors and their interaction with the microbial communities of four well-known and highly biofilm-forming pathogens, more exactly, Pseudomonas aeruginosa, Escherichia coli, Staphylococcus spp., and Candida spp. The innate and adaptive immune responses caused by the infection with these microorganisms and their evasion to the host immune system by biofilm formation are discussed in the present work. The relevance of the differences in the expression of certain virulence factors and the immune response in biofilm-associated infections when compared to planktonic infections is usually described as the biofilm architecture protects the pathogen and alters the host immune responses, here we extensively discussed these mechanisms.
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Affiliation(s)
- Sandra Pamela Cangui-Panchi
- Universidad San Francisco de Quito USFQ, Colegio de Ciencias Biológicas y Ambientales COCIBA, Instituto de Microbiología, Laboratorio de Bacteriología, Quito, Ecuador
| | - Anahí Lizbeth Ñacato-Toapanta
- Universidad San Francisco de Quito USFQ, Colegio de Ciencias Biológicas y Ambientales COCIBA, Instituto de Microbiología, Laboratorio de Bacteriología, Quito, Ecuador
| | - Leonardo Joshué Enríquez-Martínez
- Universidad San Francisco de Quito USFQ, Colegio de Ciencias Biológicas y Ambientales COCIBA, Instituto de Microbiología, Laboratorio de Bacteriología, Quito, Ecuador
| | - Gabriela Alexandra Salinas-Delgado
- Universidad San Francisco de Quito USFQ, Colegio de Ciencias Biológicas y Ambientales COCIBA, Instituto de Microbiología, Laboratorio de Bacteriología, Quito, Ecuador
| | - Jorge Reyes
- Hospital del Instituto Ecuatoriano de Seguridad Social (IESS) Quito-Sur, Quito, Ecuador
- Facultad de Ciencias Químicas, Universidad Central del Ecuador, Quito, Ecuador
| | - Daniel Garzon-Chavez
- Universidad San Francisco de Quito USFQ, Colegio de Ciencias de la Salud, Quito, Ecuador
| | - António Machado
- Universidad San Francisco de Quito USFQ, Colegio de Ciencias Biológicas y Ambientales COCIBA, Instituto de Microbiología, Laboratorio de Bacteriología, Quito, Ecuador
- Corresponding author.
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4
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Kong W, Luo W, Wang Y, Liu Y, Tian Q, Zhao C, Liang H. Dual GGDEF/EAL-Domain Protein RmcA Controls the Type III Secretion System of Pseudomonas aeruginosa by Interaction with CbrB. ACS Infect Dis 2022; 8:2441-2450. [PMID: 36379019 DOI: 10.1021/acsinfecdis.2c00212] [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: 11/16/2022]
Abstract
Cyclic diguanylate (c-di-GMP) is a major bacterial secondary signaling molecule that controls a multitude of cellular processes. More than 40 genes encoding diguanylate cyclases and phosphodiesterases have been identified in Pseudomonas aeruginosa, and many of them have been intensively investigated. However, the mechanism through which they achieve signaling specificity remains unclear. Here, we revealed that the absence of the dual GGDEF/EAL-domain protein RmcA significantly affected biofilm formation of P. aeruginosa PAO1 and led to upregulated expression of the type III secretion system (T3SS) genes; overexpression of RmcA strongly reduced the expression of T3SS. Further investigation showed that the regulatory function of RmcA was independent of the Gac/Rsm pathway. To identify the interaction partners of RmcA involved in this process, bacterial two-hybrid library screening was performed. We found that RmcA directly interacts with a two-component response regulator CbrB, which is involved in the regulation of biofilm formation and T3SS expression by RmcA. These findings reveal that the dual-domain GGDEF/EAL protein RmcA could achieve specificity of action through physical interaction with CbrB, which extends understanding the complex regulatory network of the c-di-GMP signaling.
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Affiliation(s)
- Weina Kong
- Key Laboratory of Resources Biology and Biotechnology in Western China, Ministry of Education, School of Life Sciences, Northwest University, Xi'an 710069, China
| | - Wei Luo
- Key Laboratory of Resources Biology and Biotechnology in Western China, Ministry of Education, School of Life Sciences, Northwest University, Xi'an 710069, China
| | - Yaya Wang
- Key Laboratory of Resources Biology and Biotechnology in Western China, Ministry of Education, School of Life Sciences, Northwest University, Xi'an 710069, China
| | - Yu Liu
- Key Laboratory of Resources Biology and Biotechnology in Western China, Ministry of Education, School of Life Sciences, Northwest University, Xi'an 710069, China
| | - Qianqian Tian
- Key Laboratory of Resources Biology and Biotechnology in Western China, Ministry of Education, School of Life Sciences, Northwest University, Xi'an 710069, China
| | - Cheng Zhao
- Key Laboratory of Resources Biology and Biotechnology in Western China, Ministry of Education, School of Life Sciences, Northwest University, Xi'an 710069, China
| | - Haihua Liang
- Key Laboratory of Resources Biology and Biotechnology in Western China, Ministry of Education, School of Life Sciences, Northwest University, Xi'an 710069, China.,School of Medicine, Southern University of Science and Technology, Shenzhen 518055, China
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5
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Xiong W, Perna A, Jacob IB, Lundgren BR, Wang G. The Enhancer-Binding Protein MifR, an Essential Regulator of α-Ketoglutarate Transport, Is Required for Full Virulence of Pseudomonas aeruginosa PAO1 in a Mouse Model of Pneumonia. Infect Immun 2022; 90:e0013622. [PMID: 36125307 PMCID: PMC9584295 DOI: 10.1128/iai.00136-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The opportunistic human pathogen Pseudomonas aeruginosa PAO1 has an extensive metabolism, enabling it to utilize a wide range of structurally diverse compounds to meet its nutritional and energy needs. Interestingly, the utilization of some of the more unusual compounds often associated with a eukaryotic-host environment is regulated via enhancer-binding proteins (EBPs) in P. aeruginosa. Whether the utilization of such compounds and the EBPs involved contribute to the pathogenesis of P. aeruginosa remains to be fully understood. To narrow this gap, we investigated the roles of the EBPs EatR (regulator of ethanolamine catabolism), DdaR (regulator of methylarginine catabolism), and MifR (regulator of α-ketoglutarate or α-KG transport) in the virulence of P. aeruginosa PAO1 in a pneumonia-induced septic mouse model. Deletion of genes encoding EatR and DdaR had no significant effect on the mortality of P. aeruginosa PAO1-infected mice compared to wide-type (WT) PAO1-infected mice. In contrast, infected mice with ΔmifR mutant exhibited a significant reduction (~50%) in the mortality rate compared with WT PAO1 (P < 0.05). Infected mice with ΔmifR PAO1 had lower lung injury scores, fewer inflammatory cells, decreased proinflammatory cytokines, and decreased apoptosis and cell death compared to mice infected with WT PAO1 (P < 0.05). Furthermore, molecular analysis revealed decreased NLRP3 inflammasome activation in infected mice with ΔmifR PAO1 compared to WT PAO1 (P < 0.05). These results suggested that the utilization of α-KG was a contributing factor in P. aeruginosa-mediated pneumonia and sepsis and that MifR-associated regulation may be a potential therapeutic target for P. aeruginosa infectious disease.
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Affiliation(s)
- Weichuan Xiong
- Department of Surgery, State University of New York (SUNY) Upstate Medical University, Syracuse, New York, USA
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, People’s Republic of China
| | - Alexander Perna
- Department of Surgery, State University of New York (SUNY) Upstate Medical University, Syracuse, New York, USA
| | - Ikechukwu B. Jacob
- Department of Surgery, State University of New York (SUNY) Upstate Medical University, Syracuse, New York, USA
- Department of Microbiology and Immunology, State University of New York (SUNY) Upstate Medical University, Syracuse, New York, USA
| | | | - Guirong Wang
- Department of Surgery, State University of New York (SUNY) Upstate Medical University, Syracuse, New York, USA
- Department of Microbiology and Immunology, State University of New York (SUNY) Upstate Medical University, Syracuse, New York, USA
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6
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Lee AJ, Mould DL, Crawford J, Hu D, Powers RK, Doing G, Costello JC, Hogan DA, Greene CS. SOPHIE: Generative Neural Networks Separate Common and Specific Transcriptional Responses. GENOMICS, PROTEOMICS & BIOINFORMATICS 2022; 20:912-927. [PMID: 36216026 PMCID: PMC10025681 DOI: 10.1016/j.gpb.2022.09.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 09/09/2022] [Accepted: 09/30/2022] [Indexed: 11/06/2022]
Abstract
Genome-wide transcriptome profiling identifies genes that are prone to differential expression (DE) across contexts, as well as genes with changes specific to the experimental manipulation. Distinguishing genes that are specifically changed in a context of interest from common differentially expressed genes (DEGs) allows more efficient prediction of which genes are specific to a given biological process under scrutiny. Currently, common DEGs or pathways can only be identified through the laborious manual curation of experiments, an inordinately time-consuming endeavor. Here we pioneer an approach, Specific cOntext Pattern Highlighting In Expression data (SOPHIE), for distinguishing between common and specific transcriptional patterns using a generative neural network to create a background set of experiments from which a null distribution of gene and pathway changes can be generated. We apply SOPHIE to diverse datasets including those from human, human cancer, and bacterial pathogen Pseudomonas aeruginosa. SOPHIE identifies common DEGs in concordance with previously described, manually and systematically determined common DEGs. Further molecular validation indicates that SOPHIE detects highly specific but low-magnitude biologically relevant transcriptional changes. SOPHIE's measure of specificity can complement log2 fold change values generated from traditional DE analyses. For example, by filtering the set of DEGs, one can identify genes that are specifically relevant to the experimental condition of interest. Consequently, these results can inform future research directions. All scripts used in these analyses are available at https://github.com/greenelab/generic-expression-patterns. Users can access https://github.com/greenelab/sophie to run SOPHIE on their own data.
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Affiliation(s)
- Alexandra J Lee
- Genomics and Computational Biology Graduate Program, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Dallas L Mould
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA
| | - Jake Crawford
- Genomics and Computational Biology Graduate Program, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Dongbo Hu
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Rani K Powers
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115, USA
| | - Georgia Doing
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA
| | - James C Costello
- Department of Pharmacology, University of Colorado School of Medicine, Denver, CO 80045, USA
| | - Deborah A Hogan
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA
| | - Casey S Greene
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania, Philadelphia, PA 19104, USA; Center for Health AI, University of Colorado School of Medicine, Denver, CO 80045, USA; Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Denver, CO 80045, USA.
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7
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Monteagudo-Cascales E, Santero E, Canosa I. The Regulatory Hierarchy Following Signal Integration by the CbrAB Two-Component System: Diversity of Responses and Functions. Genes (Basel) 2022; 13:genes13020375. [PMID: 35205417 PMCID: PMC8871633 DOI: 10.3390/genes13020375] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 02/14/2022] [Accepted: 02/16/2022] [Indexed: 02/04/2023] Open
Abstract
CbrAB is a two-component system, unique to bacteria of the family Pseudomonaceae, capable of integrating signals and involved in a multitude of physiological processes that allow bacterial adaptation to a wide variety of varying environmental conditions. This regulatory system provides a great metabolic versatility that results in excellent adaptability and metabolic optimization. The two-component system (TCS) CbrA-CbrB is on top of a hierarchical regulatory cascade and interacts with other regulatory systems at different levels, resulting in a robust output. Among the regulatory systems found at the same or lower levels of CbrAB are the NtrBC nitrogen availability adaptation system, the Crc/Hfq carbon catabolite repression cascade in Pseudomonas, or interactions with the GacSA TCS or alternative sigma ECF factor, such as SigX. The interplay between regulatory mechanisms controls a number of physiological processes that intervene in important aspects of bacterial adaptation and survival. These include the hierarchy in the use of carbon sources, virulence or resistance to antibiotics, stress response or definition of the bacterial lifestyle. The multiple actions of the CbrAB TCS result in an important competitive advantage.
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Affiliation(s)
| | - Eduardo Santero
- Departamento de Biología Molecular e Ingeniería Bioquímica, Universidad Pablo de Olavide, Centro Andaluz de Biología del Desarrollo, CSIC, Junta de Andalucía, 41013 Seville, Spain;
| | - Inés Canosa
- Departamento de Biología Molecular e Ingeniería Bioquímica, Universidad Pablo de Olavide, Centro Andaluz de Biología del Desarrollo, CSIC, Junta de Andalucía, 41013 Seville, Spain;
- Correspondence: ; Tel.: +34-954349052
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8
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Ducret V, Perron K, Valentini M. Role of Two-Component System Networks in Pseudomonas aeruginosa Pathogenesis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1386:371-395. [PMID: 36258080 DOI: 10.1007/978-3-031-08491-1_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Two-component systems (TCS) are the largest family of signaling systems in the bacterial kingdom. They enable bacteria to cope with a wide range of environmental conditions via the sensing of stimuli and the transduction of the signal into an appropriate cellular adaptation response. Pseudomonas aeruginosa possesses one of the richest arrays of TCSs in bacteria and they have been the subject of intense investigation for more than 20 years. Most of the P. aeruginosa TCSs characterized to date affect its pathogenesis, via the regulation of virulence factors expression, modulation of the synthesis of antibiotic/antimicrobial resistance mechanisms, and/or via linking virulence to energy metabolism. Here, we give an overview of the current knowledge on P. aeruginosa TCSs, citing key examples for each of the above-mentioned regulatory actions. We then conclude by mentioning few small molecule inhibitors of P. aeruginosa TCSs that have shown an antimicrobial action in vitro.
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Affiliation(s)
- Verena Ducret
- Microbiology Unit, Department of Botany and Plant Biology, University of Geneva, Geneva, Switzerland
| | - Karl Perron
- Microbiology Unit, Department of Botany and Plant Biology, University of Geneva, Geneva, Switzerland
| | - Martina Valentini
- Department of Microbiology and Molecular Medicine, CMU, Faculty of Medicine, University of Geneva, Geneva, Switzerland.
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9
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Alford MA, Baquir B, An A, Choi KYG, Hancock REW. NtrBC Selectively Regulates Host-Pathogen Interactions, Virulence, and Ciprofloxacin Susceptibility of Pseudomonas aeruginosa. Front Cell Infect Microbiol 2021; 11:694789. [PMID: 34249781 PMCID: PMC8264665 DOI: 10.3389/fcimb.2021.694789] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 06/03/2021] [Indexed: 12/11/2022] Open
Abstract
Pseudomonas aeruginosa is a metabolically versatile opportunistic pathogen capable of infecting distinct niches of the human body, including skin wounds and the lungs of cystic fibrosis patients. Eradication of P. aeruginosa infection is becoming increasingly difficult due to the numerous resistance mechanisms it employs. Adaptive resistance is characterized by a transient state of decreased susceptibility to antibiotic therapy that is distinct from acquired or intrinsic resistance, can be triggered by various environmental stimuli and reverted by removal of the stimulus. Further, adaptive resistance is intrinsically linked to lifestyles such as swarming motility and biofilm formation, both of which are important in infections and lead to multi-drug adaptive resistance. Here, we demonstrated that NtrBC, the master of nitrogen control, had a selective role in host colonization and a substantial role in determining intrinsic resistance to ciprofloxacin. P. aeruginosa mutant strains (ΔntrB, ΔntrC and ΔntrBC) colonized the skin but not the respiratory tract of mice as well as WT and, unlike WT, could be reduced or eradicated from the skin by ciprofloxacin. We hypothesized that nutrient availability contributed to these phenomena and found that susceptibility to ciprofloxacin was impacted by nitrogen source in laboratory media. P. aeruginosa ΔntrB, ΔntrC and ΔntrBC also exhibited distinct host interactions, including modestly increased cytotoxicity toward human bronchial epithelial cells, reduced virulence factor production and 10-fold increased uptake by macrophages. These data might explain why NtrBC mutants were less adept at colonizing the upper respiratory tract of mice. Thus, NtrBC represents a link between nitrogen metabolism, adaptation and virulence of the pathogen P. aeruginosa, and could represent a target for eradication of recalcitrant infections in situ.
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Affiliation(s)
- Morgan A Alford
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
| | - Beverlie Baquir
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
| | - Andy An
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
| | - Ka-Yee G Choi
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
| | - Robert E W Hancock
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
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10
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Wilkinson LV, Alford MA, Coleman SR, Wu BC, Lee AHY, Blimkie TM, Bains M, Falsafi R, Pletzer D, Hancock REW. Peptide 1018 inhibits swarming and influences Anr-regulated gene expression downstream of the stringent stress response in Pseudomonas aeruginosa. PLoS One 2021; 16:e0250977. [PMID: 33930077 PMCID: PMC8087004 DOI: 10.1371/journal.pone.0250977] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 04/16/2021] [Indexed: 11/20/2022] Open
Abstract
Pseudomonas aeruginosa is a ubiquitous opportunistic pathogen that causes considerable human morbidity and mortality, particularly in nosocomial infections and individuals with cystic fibrosis. P. aeruginosa can adapt to surface growth by undergoing swarming motility, a rapid multicellular movement that occurs on viscous soft surfaces with amino acids as a nitrogen source. Here we tested the small synthetic host defense peptide, innate defense regulator 1018, and found that it inhibited swarming motility at concentrations as low as 0.75 μg/ml, well below the MIC for strain PA14 planktonic cells (64 μg/ml). A screen of the PA14 transposon insertion mutant library revealed 29 mutants that were more tolerant to peptide 1018 during swarming, five of which demonstrated significantly greater swarming than the WT in the presence of peptide. Transcriptional analysis (RNA-Seq) of cells that were inoculated on swarming plates containing 1.0 μg/ml peptide revealed differential expression of 1,190 genes compared to cells swarming on plates without peptide. Furthermore, 1018 treatment distinctly altered the gene expression profile of cells when compared to that untreated cells in the centre of the swarm colonies. Peptide-treated cells exhibited changes in the expression of genes implicated in the stringent stress response including those regulated by anr, which is involved in anaerobic adaptation, indicative of a mechanism by which 1018 might inhibit swarming motility. Overall, this study illustrates potential mechanisms by which peptide 1018 inhibits swarming surface motility, an important bacterial adaptation associated with antibiotic resistance, virulence, and dissemination of P. aeruginosa.
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Affiliation(s)
- Lauren V. Wilkinson
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
| | - Morgan A. Alford
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
| | - Shannon R. Coleman
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
| | - Bing C. Wu
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
| | - Amy H. Y. Lee
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, Canada
| | - Travis M. Blimkie
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
| | - Manjeet Bains
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
| | - Reza Falsafi
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
| | - Daniel Pletzer
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Robert E. W. Hancock
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
- * E-mail:
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11
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Zhu X, Wei L, Rong X, Zhang Y, Zhang Q, Wen X, He W, Zhang K, Chen F, Wei L, Lu Y. Conjunctival Microbiota in Patients With Type 2 Diabetes Mellitus and Influences of Perioperative Use of Topical Levofloxacin in Ocular Surgery. Front Med (Lausanne) 2021; 8:605639. [PMID: 33889581 PMCID: PMC8055849 DOI: 10.3389/fmed.2021.605639] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 03/09/2021] [Indexed: 01/14/2023] Open
Abstract
Background: Patients with type 2 diabetes mellitus (T2DM) are prone to ocular surface infections. We therefore characterized the conjunctival microbiome of T2DM patients and the influence of topical levofloxacin to investigate whether a dysbiosis is associated with this phenomenon. Methods: Conjunctival microbiome of 79 T2DM patients and 113 non-diabetic controls was profiled using the 16S rDNA sequencing approach. Furthermore, 21 T2DM and 14 non-diabetic patients who underwent cataract surgeries were followed up perioperatively and the influence of pre- and post-operative levofloxacin on the conjunctival microbiome was further investigated prospectively and compared longitudinally. Results: The α-diversity of the conjunctival microbiota was significantly higher in T2DM patients than in controls (P < 0.05). Significant differences in both composition and function of the conjunctival microbiome were identified on the ocular surface of T2DM patients as compared to non-diabetic controls. Particularly, phylum Bacteroidetes and Fusobacteria, genus Pseudomonas, Haemophilus, and Empedobacter were enriched, while genus Streptococcus was reduced on the T2DM ocular surface. Microbial genes functioning of bacterial chemotaxis was elevated in the conjunctival microbiome of T2DM patients. Furthermore, compared to the initial status, several genera including Staphylococcus were more abundant in the conjunctival microbiome of T2DM patients after 3-days use of preoperative levofloxacin topically, while no genus was more abundant in the non-diabetic follow-up group. No difference was observed between initial status and 7 days after ceasing all postoperative medications in both diabetic and non-diabetic follow-up groups. Conclusions: The conjunctival microbiome of T2DM patients was more complex and may respond differently to topical antibiotics.
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Affiliation(s)
- Xiangjia Zhu
- Department of Ophthalmology and Eye Institute, Ear, Nose and Throat (ENT) Hospital of Fudan University, Shanghai, China.,National Health Commission (NHC) Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Science, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
| | - Ling Wei
- Department of Ophthalmology and Eye Institute, Ear, Nose and Throat (ENT) Hospital of Fudan University, Shanghai, China.,National Health Commission (NHC) Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Science, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
| | - Xianfang Rong
- Department of Ophthalmology and Eye Institute, Ear, Nose and Throat (ENT) Hospital of Fudan University, Shanghai, China.,National Health Commission (NHC) Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Science, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
| | - Yinglei Zhang
- Department of Ophthalmology and Eye Institute, Ear, Nose and Throat (ENT) Hospital of Fudan University, Shanghai, China.,National Health Commission (NHC) Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Science, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
| | - Qian Zhang
- Central Laboratory, Peking University School and Hospital of Stomatology, Beijing, China
| | - Xiaofeng Wen
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Wenwen He
- Department of Ophthalmology and Eye Institute, Ear, Nose and Throat (ENT) Hospital of Fudan University, Shanghai, China.,National Health Commission (NHC) Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Science, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
| | - Keke Zhang
- Department of Ophthalmology and Eye Institute, Ear, Nose and Throat (ENT) Hospital of Fudan University, Shanghai, China.,National Health Commission (NHC) Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Science, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
| | - Feng Chen
- Central Laboratory, Peking University School and Hospital of Stomatology, Beijing, China
| | - Lai Wei
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Yi Lu
- Department of Ophthalmology and Eye Institute, Ear, Nose and Throat (ENT) Hospital of Fudan University, Shanghai, China.,National Health Commission (NHC) Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Science, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
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12
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Prokaryotic Solute/Sodium Symporters: Versatile Functions and Mechanisms of a Transporter Family. Int J Mol Sci 2021; 22:ijms22041880. [PMID: 33668649 PMCID: PMC7918813 DOI: 10.3390/ijms22041880] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 02/02/2021] [Accepted: 02/10/2021] [Indexed: 11/23/2022] Open
Abstract
The solute/sodium symporter family (SSS family; TC 2.A.21; SLC5) consists of integral membrane proteins that use an existing sodium gradient to drive the uphill transport of various solutes, such as sugars, amino acids, vitamins, or ions across the membrane. This large family has representatives in all three kingdoms of life. The human sodium/iodide symporter (NIS) and the sodium/glucose transporter (SGLT1) are involved in diseases such as iodide transport defect or glucose-galactose malabsorption. Moreover, the bacterial sodium/proline symporter PutP and the sodium/sialic acid symporter SiaT play important roles in bacteria–host interactions. This review focuses on the physiological significance and structural and functional features of prokaryotic members of the SSS family. Special emphasis will be given to the roles and properties of proteins containing an SSS family domain fused to domains typically found in bacterial sensor kinases.
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13
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Shi X, Gao Z, Lin Q, Zhao L, Ma Q, Kang Y, Yu J. Meta-analysis Reveals Potential Influence of Oxidative Stress on the Airway Microbiomes of Cystic Fibrosis Patients. GENOMICS PROTEOMICS & BIOINFORMATICS 2020; 17:590-602. [PMID: 32171662 PMCID: PMC7212475 DOI: 10.1016/j.gpb.2018.03.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 03/25/2018] [Accepted: 03/28/2018] [Indexed: 12/11/2022]
Abstract
The lethal chronic airway infection of the cystic fibrosis (CF) patients is predisposed by colonization of specific CF-philic pathogens or the CF microbiomes, but key processes and reasons of the microbiome settlement in the patients are yet to be fully understood, especially their survival and metabolic dynamics from normal to diseased status under treatment. Here, we report our meta-analysis results on CF airway microbiomes based on metabolic networks reconstructed from genome information at species level. The microbiomes of CF patients appear to engage much more redox-related activities than those of controls, and by constructing a large dataset of anti-oxidative stress (anti-OS) genes, our quantitative evaluation of the anti-OS capacity of each bacterial species in the CF microbiomes confirms strong conservation of the anti-OS responses within genera and also shows that the CF pathogens have significantly higher anti-OS capacity than commensals and other typical respiratory pathogens. In addition, the anti-OS capacity of a relevant species correlates with its relative fitness for the airways of CF patients over that for the airways of controls. Moreover, the total anti-OS capacity of the respiratory microbiome of CF patients is collectively higher than that of controls, which increases with disease progression, especially after episodes of acute exacerbation and antibiotic treatment. According to these results, we propose that the increased OS in the airways of CF patients may play an important role in reshaping airway microbiomes to a more resistant status that favors the pre-infection colonization of the CF pathogens for a higher anti-OS capacity.
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Affiliation(s)
- Xing Shi
- CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100190, China
| | - Zhancheng Gao
- Department of Respiratory & Critical Care Medicine, Peking University People's Hospital, Beijing 100044, China
| | - Qiang Lin
- CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100101, China
| | - Liping Zhao
- Department of Biochemistry and Microbiology, School of Environmental and Biological Sciences, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA
| | - Qin Ma
- Bioinformatics and Mathematical Biosciences Lab, Department of Agronomy, Horticulture and Plant Science and Department of Mathematics and Statistics, South Dakota State University, Brookings, SD 57007, USA
| | - Yu Kang
- CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100101, China.
| | - Jun Yu
- CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100190, China.
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14
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Kumar SS, Penesyan A, Elbourne LDH, Gillings MR, Paulsen IT. Catabolism of Nucleic Acids by a Cystic Fibrosis Pseudomonas aeruginosa Isolate: An Adaptive Pathway to Cystic Fibrosis Sputum Environment. Front Microbiol 2019; 10:1199. [PMID: 31214142 PMCID: PMC6555301 DOI: 10.3389/fmicb.2019.01199] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Accepted: 05/13/2019] [Indexed: 11/13/2022] Open
Abstract
Pseudomonas aeruginosa is a major cause of morbidity and mortality in patients with cystic fibrosis (CF). We undertook Biolog Phenotype Microarray testing of P. aeruginosa CF isolates to investigate their catabolic capabilities compared to P. aeruginosa laboratory strains PAO1 and PA14. One strain, PASS4, displayed an unusual phenotype, only showing strong respiration on adenosine and inosine. Further testing indicated that PASS4 could grow on DNA as a sole carbon source, with a higher biomass production than PAO1. This suggested that PASS4 was specifically adapted to metabolize extracellular DNA, a substrate present at high concentrations in the CF lung. Transcriptomic and proteomic profiling of PASS4 and PAO1 when grown with DNA as a sole carbon source identified a set of upregulated genes, including virulence and host-adaptation genes. PASS4 was unable to utilize N-Acetyl-D-glucosamine, and when we selected PASS4 mutants able to grow on this carbon source, they also displayed a gain in ability to catabolize a broad range of other carbon sources. Genome sequencing of the mutants revealed they all contained mutations within the purK gene, encoding a key protein in the de novo purine biosynthesis pathway. This suggested that PASS4 was a purine auxotroph. Growth assays in the presence of 2 mM adenosine and the complementation of PASS4 with an intact purK gene confirmed this conclusion. Purine auxotrophy may represent a viable microbial strategy for adaptation to DNA-rich environments such as the CF lung.
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Affiliation(s)
| | - Anahit Penesyan
- Department of Molecular Sciences, Macquarie University, Sydney, NSW, Australia
| | | | - Michael R Gillings
- Department of Biological Sciences, Macquarie University, Sydney, NSW, Australia
| | - Ian T Paulsen
- Department of Molecular Sciences, Macquarie University, Sydney, NSW, Australia
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15
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Rossi E, Paroni M, Landini P. Biofilm and motility in response to environmental and host-related signals in Gram negative opportunistic pathogens. J Appl Microbiol 2018; 125:1587-1602. [PMID: 30153375 DOI: 10.1111/jam.14089] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 05/30/2018] [Accepted: 07/20/2018] [Indexed: 12/13/2022]
Abstract
Most bacteria can switch between a planktonic, sometimes motile, form and a biofilm mode, in which bacterial cells can aggregate and attach to a solid surface. The transition between these two forms represents an example of bacterial adaptation to environmental signals and stresses. In 'environmental pathogens', namely, environmental bacteria that are also able to cause disease in animals and humans, signals associated either with the host or with the external environment, such as temperature, oxygen availability, nutrient concentrations etc., play a major role in triggering the switch between the motile and the biofilm mode, via complex regulatory mechanisms that control flagellar synthesis and motility, and production of adhesion factors. In this review article, we present examples of how environmental signals can impact biofilm formation and cell motility in the Gram negative bacteria Pseudomonas aeruginosa, Escherichia coli and in the Burkholderia genus, and how the switch between motile and biofilm mode can be an essential part of a more general process of adaptation either to the host or to the external environment.
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Affiliation(s)
- E Rossi
- Department of Clinical Microbiology, Rigshospitalet, København, Denmark
| | - M Paroni
- Department of Biosciences, Università degli Studi di Milano, Milan, Italy
| | - P Landini
- Department of Biosciences, Università degli Studi di Milano, Milan, Italy
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16
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Gellatly SL, Bains M, Breidenstein EBM, Strehmel J, Reffuveille F, Taylor PK, Yeung ATY, Overhage J, Hancock REW. Novel roles for two-component regulatory systems in cytotoxicity and virulence-related properties in Pseudomonas aeruginosa. AIMS Microbiol 2018; 4:173-191. [PMID: 31294209 PMCID: PMC6605022 DOI: 10.3934/microbiol.2018.1.173] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 02/26/2018] [Indexed: 11/18/2022] Open
Abstract
The rapid adaptation of the opportunistic bacterial pathogen Pseudomonas aeruginosa to various growth modes and environmental conditions is controlled in part through diverse two-component regulatory systems. Some of these systems are well studied, but the majority are poorly characterized, even though it is likely that several of these systems contribute to virulence. Here, we screened all available strain PA14 mutants in 50 sensor kinases, 50 response regulators and 5 hybrid sensor/regulators, for contributions to cytotoxicity against cultured human bronchial epithelial cells, as assessed by the release of cytosolic lactate dehydrogenase. This enabled the identification of 8 response regulators and 3 sensor kinases that caused substantial decreases in cytotoxicity, and 5 response regulators and 8 sensor kinases that significantly increased cytotoxicity by 15-58% or more. These regulators were additionally involved in motility, adherence, type 3 secretion, production of cytotoxins, and the development of biofilms. Here we investigated in more detail the roles of FleSR, PilSR and WspR. Not all cognate pairs contributed to cytotoxicity (e.g. PhoPQ, PilSR) in the same way and some differences could be detected between the same mutants in PAO1 and PA14 strain backgrounds (e.g. FleSR, PhoPQ). This study highlights the potential importance of these regulators and their downstream targets on pathogenesis and demonstrates that cytotoxicity can be regulated by several systems and that their contributions are partly dependent on strain background.
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Affiliation(s)
- Shaan L Gellatly
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology & Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Manjeet Bains
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology & Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Elena B M Breidenstein
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology & Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Janine Strehmel
- Microbiology of Natural and Technical Interfaces Department, Institute of Functional Interfaces (IFG), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Fany Reffuveille
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology & Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Patrick K Taylor
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology & Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Amy T Y Yeung
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology & Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Joerg Overhage
- Microbiology of Natural and Technical Interfaces Department, Institute of Functional Interfaces (IFG), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Robert E W Hancock
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology & Immunology, University of British Columbia, Vancouver, BC, Canada
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17
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Francis VI, Stevenson EC, Porter SL. Two-component systems required for virulence in Pseudomonas aeruginosa. FEMS Microbiol Lett 2018; 364:3828290. [PMID: 28510688 PMCID: PMC5812489 DOI: 10.1093/femsle/fnx104] [Citation(s) in RCA: 108] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Accepted: 05/15/2017] [Indexed: 11/13/2022] Open
Abstract
Pseudomonas aeruginosa is a versatile opportunistic pathogen capable of infecting a broad range of hosts, in addition to thriving in a broad range of environmental conditions outside of hosts. With this versatility comes the need to tightly regulate its genome to optimise its gene expression and behaviour to the prevailing conditions. Two-component systems (TCSs) comprising sensor kinases and response regulators play a major role in this regulation. This minireview discusses the growing number of TCSs that have been implicated in the virulence of P. aeruginosa, with a special focus on the emerging theme of multikinase networks, which are networks comprising multiple sensor kinases working together, sensing and integrating multiple signals to decide upon the best response. The networks covered in depth regulate processes such as the switch between acute and chronic virulence (GacS network), the Cup fimbriae (Roc network and Rcs/Pvr network), the aminoarabinose modification of lipopolysaccharide (a network involving the PhoQP and PmrBA TCSs), twitching motility and virulence (a network formed from the Chp chemosensory pathway and the FimS/AlgR TCS), and biofilm formation (Wsp chemosensory pathway). In addition, we highlight the important interfaces between these systems and secondary messenger signals such as cAMP and c-di-GMP.
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Affiliation(s)
- Vanessa I Francis
- Biosciences, Geoffrey Pope Building, College of Life and Environmental Sciences, University of Exeter, Exeter EX 4QD, UK
| | - Emma C Stevenson
- Biosciences, Geoffrey Pope Building, College of Life and Environmental Sciences, University of Exeter, Exeter EX 4QD, UK
| | - Steven L Porter
- Biosciences, Geoffrey Pope Building, College of Life and Environmental Sciences, University of Exeter, Exeter EX 4QD, UK
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18
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Strempel N, Nusser M, Neidig A, Brenner-Weiss G, Overhage J. The Oxidative Stress Agent Hypochlorite Stimulates c-di-GMP Synthesis and Biofilm Formation in Pseudomonas aeruginosa. Front Microbiol 2017; 8:2311. [PMID: 29213262 PMCID: PMC5702645 DOI: 10.3389/fmicb.2017.02311] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 11/08/2017] [Indexed: 01/25/2023] Open
Abstract
The opportunistic human pathogen Pseudomonas aeruginosa is able to survive under a variety of often harmful environmental conditions due to a multitude of intrinsic and adaptive resistance mechanisms, including biofilm formation as one important survival strategy. Here, we investigated the adaptation of P. aeruginosa PAO1 to hypochlorite (HClO), a phagocyte-derived host defense compound and frequently used disinfectant. In static biofilm assays, we observed a significant enhancement in initial cell attachment in the presence of sublethal HClO concentrations. Subsequent LC-MS analyses revealed a strong increase in cyclic-di-GMP (c-di-GMP) levels suggesting a key role of this second messenger in HClO-induced biofilm development. Using DNA microarrays, we identified a 26-fold upregulation of ORF PA3177 coding for a putative diguanylate cyclase (DGC), which catalyzes the synthesis of the second messenger c-di-GMP – an important regulator of bacterial motility, sessility and persistence. This DGC PA3177 was further characterized in more detail demonstrating its impact on P. aeruginosa motility and biofilm formation. In addition, cell culture assays attested a role for PA3177 in the response of P. aeruginosa to human phagocytes. Using a subset of different mutants, we were able to show that both Pel and Psl exopolysaccharides are effectors in the PA3177-dependent c-di-GMP network.
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Affiliation(s)
- Nikola Strempel
- Institute of Functional Interfaces, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Michael Nusser
- Institute of Functional Interfaces, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Anke Neidig
- Institute of Functional Interfaces, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Gerald Brenner-Weiss
- Institute of Functional Interfaces, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Joerg Overhage
- Institute of Functional Interfaces, Karlsruhe Institute of Technology, Karlsruhe, Germany.,Department of Health Sciences, Carleton University, Ottawa, ON, Canada
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19
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Sepulveda E, Lupas AN. Characterization of the CrbS/R Two-Component System in Pseudomonas fluorescens Reveals a New Set of Genes under Its Control and a DNA Motif Required for CrbR-Mediated Transcriptional Activation. Front Microbiol 2017; 8:2287. [PMID: 29250042 PMCID: PMC5715377 DOI: 10.3389/fmicb.2017.02287] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 11/06/2017] [Indexed: 01/18/2023] Open
Abstract
The CrbS/R system is a two-component signal transduction system that regulates acetate utilization in Vibrio cholerae, P. aeruginosa, and P. entomophila. CrbS is a hybrid histidine kinase that belongs to a recently identified family, in which the signaling domain is fused to an SLC5 solute symporter domain through aSTAC domain. Upon activation by CrbS, CrbR activates transcription of the acs gene, which encodes an acetyl-CoA synthase (ACS), and the actP gene, which encodes an acetate/solute symporter. In this work, we characterized the CrbS/R system in Pseudomonas fluorescens SBW25. Through the quantitative proteome analysis of different mutants, we were able to identify a new set of genes under its control, which play an important role during growth on acetate. These results led us to the identification of a conserved DNA motif in the putative promoter region of acetate-utilization genes in the Gammaproteobacteria that is essential for the CrbR-mediated transcriptional activation of genes under acetate-utilizing conditions. Finally, we took advantage of the existence of a second SLC5-containing two-component signal transduction system in P. fluorescens, CbrA/B, to demonstrate that the activation of the response regulator by the histidine kinase is not dependent on substrate transport through the SLC5 domain.
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Affiliation(s)
- Edgardo Sepulveda
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Andrei N Lupas
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, Tübingen, Germany
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20
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Lorenz A, Pawar V, Häussler S, Weiss S. Insights into host-pathogen interactions from state-of-the-art animal models of respiratory Pseudomonas aeruginosa infections. FEBS Lett 2016; 590:3941-3959. [PMID: 27730639 DOI: 10.1002/1873-3468.12454] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2016] [Revised: 10/04/2016] [Accepted: 10/07/2016] [Indexed: 12/29/2022]
Abstract
Pseudomonas aeruginosa is an important opportunistic pathogen that can cause acute respiratory infections in immunocompetent patients or chronic infections in immunocompromised individuals and in patients with cystic fibrosis. When acquiring the chronic infection state, bacteria are encapsulated within biofilm structures enabling them to withstand diverse environmental assaults, including immune reactions and antimicrobial therapy. Understanding the molecular interactions within the bacteria, as well as with the host or other bacteria, is essential for developing innovative treatment strategies. Such knowledge might be accumulated in vitro. However, it is ultimately necessary to confirm these findings in vivo. In the present Review, we describe state-of-the-art in vivo models that allow studying P. aeruginosa infections in molecular detail. The portrayed mammalian models exclusively focus on respiratory infections. The data obtained by alternative animal models which lack lung tissue, often provide molecular insights that are easily transferable to mammals. Importantly, these surrogate in vivo systems reveal complex molecular interactions of P. aeruginosa with the host. Herein, we also provide a critical assessment of the advantages and disadvantages of such models.
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Affiliation(s)
- Anne Lorenz
- Institute for Molecular Bacteriology, Center of Clinical and Experimental Infection Research, TWINCORE GmbH, A Joint Venture of the Hannover Medical School and the Helmholtz Center for Infection Research, Germany
| | - Vinay Pawar
- Department of Molecular Bacteriology, Helmholtz Center for Infection Research, Braunschweig, Germany.,Department of Molecular Immunology, Helmholtz Center for Infection Research, Braunschweig, Germany.,Institute of Immunology, Medical School Hannover, Germany
| | - Susanne Häussler
- Institute for Molecular Bacteriology, Center of Clinical and Experimental Infection Research, TWINCORE GmbH, A Joint Venture of the Hannover Medical School and the Helmholtz Center for Infection Research, Germany.,Department of Molecular Bacteriology, Helmholtz Center for Infection Research, Braunschweig, Germany
| | - Siegfried Weiss
- Department of Molecular Immunology, Helmholtz Center for Infection Research, Braunschweig, Germany.,Institute of Immunology, Medical School Hannover, Germany
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21
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Yin G, Zeng Q, Zhao H, Wu P, Cai S, Deng L, Jiang W. Effect and mechanism of calpains on pediatric lobar pneumonia. Bioengineered 2016; 8:374-382. [PMID: 27786573 PMCID: PMC5553339 DOI: 10.1080/21655979.2016.1234544] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Lobar pneumonia, one of the community-acquired pneumonia (CAP), is a common pediatric low respiratory tract infection. Calpains are Ca2+-activated cysteine proteases whose activation mechanism is elusive. The present study was undertaken to detect the role and mechanism of calpains in pediatric lobar pneumonia. The human acute lung infection model (ALIM) was constructed and infected by Streptococcus. Enzyme-linked immunosorbent assay (ELISA) was used to measure interleukin (IL)-6, IL-8 and tumor necrosis factor (TNF)-α. We observed the lactate dehydrogenase (LDH) release, calpains activity and calpain inhibitor effects in ALIM. The expression of proliferating cell nuclear antigen (PCNA) protein was quantified by western blotting. Then the effects of calpain 1 and 2 knockdown on expressions of inflammation factors and PCNA protein, LDH release and apoptosis were evaluated in lung MRC-5 cells. In constructed ALIM, expressions of IL-6 (P < 0.01), IL-8 (P < 0.01), TNF-α (P < 0.05) and PCNA protein (P < 0.05) were significantly reduced by the calpain inhibitor. Expressions of IL-6, IL-8, TNF-α, PCNA protein and relative LDH release were statistically reduced by the small interfering (si) RNA-calpain 1 and 2 in MRC-5 cells (P < 0.05). Calpains silence increased apoptotic cells from 5% (negative control) to more than 20% in MRC-5 cells. The present study suggests that calpains possess a significant effect on inflammations, cell proliferation and apoptosis. Suppression of calpains may provide a potential therapeutic target of lobar pneumonia.
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Affiliation(s)
- Genquan Yin
- a Chronic Airways Disease Laboratory, Department of Respiratory and Critical Care Medicine , Nanfang Hospital, Southern Medical University , Guangzhou , Guangdong Province , China.,b Guangzhou Women and Children's Medical Center , Guangzhou Medical University , Guangzhou , Guangdong Province , China
| | - Qiang Zeng
- b Guangzhou Women and Children's Medical Center , Guangzhou Medical University , Guangzhou , Guangdong Province , China
| | - Haijin Zhao
- a Chronic Airways Disease Laboratory, Department of Respiratory and Critical Care Medicine , Nanfang Hospital, Southern Medical University , Guangzhou , Guangdong Province , China
| | - Peiqiong Wu
- b Guangzhou Women and Children's Medical Center , Guangzhou Medical University , Guangzhou , Guangdong Province , China
| | - Shaoxi Cai
- a Chronic Airways Disease Laboratory, Department of Respiratory and Critical Care Medicine , Nanfang Hospital, Southern Medical University , Guangzhou , Guangdong Province , China
| | - Li Deng
- b Guangzhou Women and Children's Medical Center , Guangzhou Medical University , Guangzhou , Guangdong Province , China
| | - Wenhui Jiang
- b Guangzhou Women and Children's Medical Center , Guangzhou Medical University , Guangzhou , Guangdong Province , China
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22
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Role of the Transporter-Like Sensor Kinase CbrA in Histidine Uptake and Signal Transduction. J Bacteriol 2015; 197:2867-78. [PMID: 26148710 DOI: 10.1128/jb.00361-15] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Accepted: 06/17/2015] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED CbrA is an atypical sensor kinase found in Pseudomonas. The autokinase domain is connected to a putative transporter of the sodium/solute symporter family (SSSF). CbrA functions together with its cognate response regulator, CbrB, and plays an important role in nutrient acquisition, including regulation of hut genes for the utilization of histidine and its derivative, urocanate. Here we report on the findings of a genetic and biochemical analysis of CbrA with a focus on the function of the putative transporter domain. The work was initiated with mutagenesis of histidine uptake-proficient strains to identify histidine-specific transport genes located outside the hut operon. Genes encoding transporters were not identified, but mutations were repeatedly found in cbrA. This, coupled with the findings of [(3)H]histidine transport assays and further mutagenesis, implicated CbrA in histidine uptake. In addition, mutations in different regions of the SSSF domain abolished signal transduction. Site-specific mutations were made at four conserved residues: W55 and G172 (SSSF domain), H766 (H box), and N876 (N box). The mutations W55G, G172H, and N876G compromised histidine transport but had minimal effects on signal transduction. The H766G mutation abolished both transport and signal transduction, but the capacity to transport histidine was restored upon complementation with a transport-defective allele of CbrA, most likely due to interdomain interactions. Our combined data implicate the SSSF domain of CbrA in histidine transport and suggest that transport is coupled to signal transduction. IMPORTANCE Nutrient acquisition in bacteria typically involves membrane-bound sensors that, via cognate response regulators, determine the activity of specific transporters. However, nutrient perception and uptake are often coupled processes. Thus, from a physiological perspective, it would make sense for systems that couple the process of signaling and transport within a single protein and where transport is itself the stimulus that precipitates signal transduction to have evolved. The CbrA regulator in Pseudomonas represents a unique type of sensor kinase whose autokinase domain is connected to a transporter domain. We present genetic and biochemical evidence that suggests that CbrA plays a dual role in histidine uptake and sensing and that transport is dependent on signal transduction.
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