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Zhang Y, Chew BLA, Wang J, Yuan M, Yam JKH, Luo D, Yang L. Structural basis for the inhibitory mechanism of auranofin and gold(I) analogues against Pseudomonas aeruginosa global virulence factor regulator Vfr. Comput Struct Biotechnol J 2023; 21:2137-2146. [PMID: 37007650 PMCID: PMC10060147 DOI: 10.1016/j.csbj.2023.03.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 03/09/2023] [Accepted: 03/11/2023] [Indexed: 03/16/2023] Open
Abstract
Pseudomonas aeruginosa is a leading cause of hospital-acquired infections. Treatment of P. aeruginosa infections is difficult given its multiple virulence mechanisms, intrinsic antibiotic resistance mechanisms, and biofilm-forming ability. Auranofin, an approved oral gold compound for rheumatoid arthritis treatment, was recently reported to inhibit the growth of multiple bacterial species. Here, we identify P. aeruginosa's global virulence factor regulator Vfr as one target of auranofin. We report the mechanistic insights into the inhibitory mechanism of auranofin and gold(I) analogues to Vfr through structural, biophysical, and phenotypic inhibition studies. This work suggests that auranofin and gold(I) analogues have potential to be developed as anti-virulence drugs against P. aeruginosa.
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Affiliation(s)
- Yingdan Zhang
- Shenzhen Third People’s Hospital, The Second Affiliated Hospital of Southern University of Science and Technology, National Clinical Research Center for Infectious Disease, Shenzhen 518112, China
- School of Medicine, Southern University of Science and Technology, Shenzhen 518055, Guangdong, China
| | - Bing Liang Alvin Chew
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 636921
- NTU Institute of Structural Biology, Nanyang Technological University, EMB 06-01, 59 Nanyang Drive, 636921, Singapore
- Singapore Centre for Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University, Singapore
| | - Jing Wang
- School of Medicine, Southern University of Science and Technology, Shenzhen 518055, Guangdong, China
| | - Mingjun Yuan
- Singapore Centre for Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University, Singapore
- Guanghua Science and Technology Research Institute (Guangdong) Co., Ltd, China
| | - Joey Kuok Hoong Yam
- Singapore Centre for Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University, Singapore
| | - Dahai Luo
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 636921
- NTU Institute of Structural Biology, Nanyang Technological University, EMB 06-01, 59 Nanyang Drive, 636921, Singapore
- Corresponding author at: Lee Kong Chian School of Medicine, Nanyang Technological University, 636921, Singapore.
| | - Liang Yang
- Shenzhen Third People’s Hospital, The Second Affiliated Hospital of Southern University of Science and Technology, National Clinical Research Center for Infectious Disease, Shenzhen 518112, China
- School of Medicine, Southern University of Science and Technology, Shenzhen 518055, Guangdong, China
- Singapore Centre for Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University, Singapore
- Corresponding author at: Shenzhen Third People’s Hospital, The Second Affiliated Hospital of Southern University of Science and Technology, National Clinical Research Center for Infectious Disease, Shenzhen 518112, China.
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2
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Auranofin inhibits virulence pathways in Pseudomonas aeruginosa. Bioorg Med Chem 2023; 79:117167. [PMID: 36682225 DOI: 10.1016/j.bmc.2023.117167] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 12/18/2022] [Accepted: 01/09/2023] [Indexed: 01/13/2023]
Abstract
Pseudomonas aeruginosa is widely attributed as the leading cause of hospital-acquired infections. Due to intrinsic antibiotic resistance mechanisms and the ability to form biofilms, P. aeruginosa infections are challenging to treat. P. aeruginosa employs multiple virulence mechanisms to establish infections, many of which are controlled by the global virulence regulator Vfr. An attractive strategy to combat P. aeruginosa infections is thus the use of anti-virulence compounds. Here, we report the discovery that FDA-approved drug auranofin attenuates virulence pathways in P. aeruginosa, including quorum sensing (QS) and Type IV pili (TFP). We show that auranofin acts via multiple targets, one of which being Vfr. Consistent with inhibition of QS and TFP expression, we show that auranofin attenuates biofilm maturation, and when used in combination with colistin, displays strong synergy in eradicating P. aeruginosa biofilms. Auranofin may have immediate applications as an anti-virulence drug against P. aeruginosa infections.
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3
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OsaR (PA0056) functions as a repressor of the gene fleQ encoding an important motility regulator in Pseudomonas aeruginosa. J Bacteriol 2021; 203:e0014521. [PMID: 34339300 DOI: 10.1128/jb.00145-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
FleQ plays a crucial role in motility and biofilm formation by regulating flagellar and exopolysaccharide biosynthesis in Pseudomonas aeruginosa. It has been reported that the expression of FleQ is transcriptionally downregulated by the virulence factor regulator Vfr. Herein we demonstrated that a LysR-type transcriptional regulator, OsaR, is also capable of binding to the promoter region of fleQ and repressing its transcription. Through gel shift and DNase I footprinting assays, the OsaR binding site was identified and characterized as a dual LysR-type transcriptional regulator box (AT-N11-AT-N7-A-N11-T). Mutation of the A-T palindromic base pairs in fleQ promoter not only reduced the binding affinity of OsaR in vitro, but also de-repressed fleQ transcription in vivo. The OsaR binding site was found to cover the Vfr binding site; knockout of osaR or vfr separately exhibited no effect on the transcriptional level of fleQ; however, fleQ expression was repressed by overexpression of osaR or vfr. Furthermore, simultaneously deleting both osaR and vfr resulted in an upregulation of fleQ, but it could be complemented by the expression of either of the two repressors. In summary, our work revealed that OsaR and Vfr function as two transcriptional repressors of fleQ that bind to the same region of fleQ but work separately. IMPORTANCE Pseudomonas aeruginosa is a widespread human pathogen, which accounts for serious infections in the hospital, especially for lung infection in cystic fibrosis and chronic obstructive pulmonary disease patients. P. aeruginosa infection is closely associated with its motility and biofilm formation, which are both under the regulation of the important transcription factor FleQ. However, the upstream regulatory mechanisms of fleQ have not been fully elucidated. Therefore, our research identifying a novel regulator of fleQ as well as new regulatory mechanisms controlling its expression will be significant for better understanding the intricate gene regulatory mechanisms related to P. aeruginosa virulence and infection.
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Cautionary Notes on the Use of Arabinose- and Rhamnose-Inducible Expression Vectors in Pseudomonas aeruginosa. J Bacteriol 2021; 203:e0022421. [PMID: 34096777 DOI: 10.1128/jb.00224-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The Pseudomonas aeruginosa virulence factor regulator (Vfr) is a cyclic AMP (cAMP)-responsive transcription factor homologous to the Escherichia coli cAMP receptor protein (CRP). Unlike CRP, which plays a central role in E. coli energy metabolism and catabolite repression, Vfr is primarily involved in the control of P. aeruginosa virulence factor expression. Expression of the Vfr regulon is controlled at the level of vfr transcription, Vfr translation, cAMP synthesis, and cAMP degradation. While investigating mechanisms that regulate Vfr translation, we placed vfr transcription under the control of the rhaBp rhamnose-inducible promoter system (designated PRha) and found that PRha promoter activity was highly dependent upon vfr. Vfr dependence was also observed for the araBp arabinose-inducible promoter (designated PBAD). The observation of Vfr dependence was not entirely unexpected. Both promoters are derived from E. coli, where maximal promoter activity is dependent upon CRP. Like CRP, we found that Vfr directly binds to promoter probes derived from the PRha and PBAD promoters in vitro. Because Vfr-cAMP activity is highly integrated into numerous global regulatory systems, including c-di-GMP signaling, the Gac/Rsm system, MucA/AlgU/AlgZR signaling, and Hfq/sRNAs, the potential exists for significant variability in PRha and PBAD promoter activity in a variety of genetic backgrounds, and use of these promoter systems in P. aeruginosa should be employed with caution. IMPORTANCE Heterologous gene expression and complementation constitute a valuable and widely utilized tool in bacterial genetics. The arabinose-inducible ParaBAD (PBAD) and rhamnose-inducible PrhaBAD (PRha) promoter systems are commonly used in P. aeruginosa genetics and prized for the tight control and dynamic expression ranges that can be achieved. In this study, we demonstrate that the activity of both promoters is dependent upon the cAMP-dependent transcription factor Vfr. While this poses an obvious problem for use in a vfr mutant background, the issue is more pervasive, considering that vfr transcription/synthesis and cAMP homeostasis are highly integrated into the cellular physiology of the organism and influenced by numerous global regulatory systems. Fortunately, the synthetic PTac promoter is not subject to Vfr regulatory control.
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Xia A, Qian M, Wang C, Huang Y, Liu Z, Ni L, Jin F. Optogenetic Modification of Pseudomonas aeruginosa Enables Controllable Twitching Motility and Host Infection. ACS Synth Biol 2021; 10:531-541. [PMID: 33667080 DOI: 10.1021/acssynbio.0c00559] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cyclic adenosine monophosphate (cAMP) is an important secondary messenger that controls carbon metabolism, type IVa pili biogenesis, and virulence in Pseudomonas aeruginosa. Precise manipulation of bacterial intracellular cAMP levels may enable tunable control of twitching motility or virulence, and optogenetic tools are attractive because they afford excellent spatiotemporal resolution and are easy to operate. Here, we developed an engineered P. aeruginosa strain (termed pactm) with light-dependent intracellular cAMP levels through introducing a photoactivated adenylate cyclase gene (bPAC) into bacteria. On blue light illumination, pactm displayed a 15-fold increase in the expression of the cAMP responsive promoter and an 8-fold increase in its twitching activity. The skin lesion area of nude mouse in a subcutaneous infection model after 2-day pactm inoculation was increased 14-fold by blue light, making pactm suitable for applications in controllable bacterial host infection. In addition, we achieved directional twitching motility of pactm colonies through localized light illumination, which will facilitate the studies of contact-dependent interactions between microbial species.
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Affiliation(s)
- Aiguo Xia
- CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, PR China
| | - Mingjie Qian
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, PR China
| | - Congcong Wang
- Department of Chemical Physics, University of Science and Technology of China, No. 96, JinZhai Road Baohe District, Hefei, Anhui 230026, PR China
| | - Yajia Huang
- CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, PR China
| | - Zhi Liu
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, PR China
| | - Lei Ni
- CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, PR China
| | - Fan Jin
- CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, PR China
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, No. 96, JinZhai Road Baohe District, Hefei, Anhui 230026, PR China
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6
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Fitting Pieces into the Puzzle of Pseudomonas aeruginosa Type III Secretion System Gene Expression. J Bacteriol 2019; 201:JB.00209-19. [PMID: 31010903 DOI: 10.1128/jb.00209-19] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Type III secretion systems (T3SS) are widely distributed in Gram-negative microorganisms and critical for host-pathogen and host-symbiont interactions with plants and animals. Central features of the T3SS are a highly conserved set of secretion and translocation genes and contact dependence wherein host-pathogen interactions trigger effector protein delivery and serve as an inducing signal for T3SS gene expression. In addition to these conserved features, there are pathogen-specific properties that include a unique repertoire of effector genes and mechanisms to control T3SS gene expression. The Pseudomonas aeruginosa T3SS serves as a model system to understand transcriptional and posttranscriptional mechanisms involved in the control of T3SS gene expression. The central regulatory feature is a partner-switching system that controls the DNA-binding activity of ExsA, the primary regulator of T3SS gene expression. Superimposed upon the partner-switching mechanism are cyclic AMP and cyclic di-GMP signaling systems, two-component systems, global regulators, and RNA-binding proteins that have positive and negative effects on ExsA transcription and/or synthesis. In the present review, we discuss advances in our understanding of how these regulatory systems orchestrate the activation of T3SS gene expression in the context of acute infections and repression of the T3SS as P. aeruginosa adapts to and colonizes the cystic fibrosis airways.
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Rossello J, Lima A, Gil M, Rodríguez Duarte J, Correa A, Carvalho PC, Kierbel A, Durán R. The EAL-domain protein FcsR regulates flagella, chemotaxis and type III secretion system in Pseudomonas aeruginosa by a phosphodiesterase independent mechanism. Sci Rep 2017; 7:10281. [PMID: 28860517 PMCID: PMC5579053 DOI: 10.1038/s41598-017-09926-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Accepted: 08/02/2017] [Indexed: 11/18/2022] Open
Abstract
The second messenger c-di-GMP regulates the switch between motile and sessile bacterial lifestyles. A general feature of c-di-GMP metabolism is the presence of a surprisingly large number of genes coding for diguanylate cyclases and phosphodiesterases, the enzymes responsible for its synthesis and degradation respectively. However, the physiological relevance of this apparent redundancy is not clear, emphasizing the need for investigating the functions of each of these enzymes. Here we focused on the phosphodiesterase PA2133 from Pseudomonas aeruginosa, an important opportunistic pathogen. We phenotypically characterized P. aeruginosa strain K overexpressing PA2133 or its inactive mutant. We showed that biofilm formation and motility are severely impaired by overexpression of PA2133. Our quantitative proteomic approach applied to the membrane and exoprotein fractions revealed that proteins involved in three processes were mostly affected: flagellar motility, type III secretion system and chemotaxis. While inhibition of biofilm formation can be ascribed to the phosphodiesterase activity of PA2133, down-regulation of flagellar, chemotaxis, and type III secretion system proteins is independent of this enzymatic activity. Based on these unexpected effects of PA2133, we propose to rename this gene product FcsR, for Flagellar, chemotaxis and type III secretion system Regulator.
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Affiliation(s)
- Jessica Rossello
- Analytical Biochemistry and Proteomics Unit, Institut Pasteur de Montevideo/Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay
| | - Analía Lima
- Analytical Biochemistry and Proteomics Unit, Institut Pasteur de Montevideo/Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay
| | - Magdalena Gil
- Analytical Biochemistry and Proteomics Unit, Institut Pasteur de Montevideo/Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay.,Unit of Dynamics of Host-Pathogen Interactions, Institut Pasteur, Paris, France
| | - Jorge Rodríguez Duarte
- Analytical Biochemistry and Proteomics Unit, Institut Pasteur de Montevideo/Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay
| | - Agustín Correa
- Unidad de Proteínas Recombinantes, Institut Pasteur de Montevideo, Montevideo, Uruguay
| | - Paulo C Carvalho
- Laboratory for Proteomics and Protein Engineering, Carlos Chagas Institute, Fiocruz-Paraná, Curitiba, Brazil
| | - Arlinet Kierbel
- Instituto de Investigaciones Biotecnológicas Dr. Rodolfo A. Ugalde (IIB-INTECH), Universidad Nacional de San Martín, Consejo Nacional de Investigaciones Científicas y Técnicas (UNSAM-CONICET), San Martín, Buenos Aires, Argentina
| | - Rosario Durán
- Analytical Biochemistry and Proteomics Unit, Institut Pasteur de Montevideo/Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay.
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8
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Abstract
Polymicrobial interactions are complex and can influence the course of an infection, as is the case when two or more species exhibit a synergism that produces a disease state not seen with any of the individual species alone. Cell-to-cell signaling is key to many of these interactions, but little is understood about how the host environment influences polymicrobial interactions or signaling between bacteria. Chronic wounds are typically polymicrobial, with Staphylococcus aureus and Pseudomonas aeruginosa being the two most commonly isolated species. While P. aeruginosa readily kills S. aureusin vitro, the two species can coexist for long periods together in chronic wound infections. In this study, we investigated the ability of components of the wound environment to modulate interactions between P. aeruginosa and S. aureus We demonstrate that P. aeruginosa quorum sensing is inhibited by physiological levels of serum albumin, which appears to bind and sequester some homoserine lactone quorum signals, resulting in the inability of P. aeruginosa to produce virulence factors that kill S. aureus These data could provide important clues regarding the virulence of P. aeruginosa in albumin-depleted versus albumin-rich infection sites and an understanding of the nature of friendly versus antagonistic interactions between P. aeruginosa and S. aureus.
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Vyshnava SS, Kanderi DK, Panjala SP, Pandian K, Bontha RR, Goukanapalle PKR, Banaganapalli B. Effect of Silver Nanoparticles Against the Formation of Biofilm by Pseudomonas aeruginosa an In silico Approach. Appl Biochem Biotechnol 2016; 180:426-437. [DOI: 10.1007/s12010-016-2107-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 04/27/2016] [Indexed: 11/28/2022]
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Pompilio A, Crocetta V, De Nicola S, Verginelli F, Fiscarelli E, Di Bonaventura G. Cooperative pathogenicity in cystic fibrosis: Stenotrophomonas maltophilia modulates Pseudomonas aeruginosa virulence in mixed biofilm. Front Microbiol 2015; 6:951. [PMID: 26441885 PMCID: PMC4584994 DOI: 10.3389/fmicb.2015.00951] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 08/27/2015] [Indexed: 12/23/2022] Open
Abstract
The present study was undertaken in order to understand more about the interaction occurring between S. maltophilia and P. aeruginosa, which are frequently co-isolated from CF airways. For this purpose, S. maltophilia RR7 and P. aeruginosa RR8 strains, co-isolated from the lung of a chronically infected CF patient during a pulmonary exacerbation episode, were evaluated for reciprocal effect during planktonic growth, adhesion and biofilm formation onto both polystyrene and CF bronchial cell monolayer, motility, as well as for gene expression in mixed biofilms. P. aeruginosa significantly affected S. maltophilia growth in both planktonic and biofilm cultures, due to an inhibitory activity probably requiring direct contact. Conversely, no effect was observed on P. aeruginosa by S. maltophilia. Compared with monocultures, the adhesiveness of P. aeruginosa on CFBE41o- cells was significantly reduced by S. maltophilia, which probably acts by reducing P. aeruginosa's swimming motility. An opposite trend was observed for biofilm formation, confirming the findings obtained using polystyrene. When grown in mixed biofilm with S. maltophilia, P. aeruginosa significantly over-expressed aprA, and algD-codifying for protease and alginate, respectively-while the quorum sensing related rhlR and lasI genes were down-regulated. The induced alginate expression by P. aeruginosa might be responsible for the protection of S. maltophilia against tobramycin activity we observed in mixed biofilms. Taken together, our results suggest that the existence of reciprocal interference of S. maltophilia and P. aeruginosa in CF lung is plausible. In particular, S. maltophilia might confer some selective "fitness advantage" to P. aeruginosa under the specific conditions of chronic infection or, alternatively, increase the virulence of P. aeruginosa thus leading to pulmonary exacerbation.
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Affiliation(s)
- Arianna Pompilio
- Department of Medical, Oral and Biotechnological Sciences, "G. d'Annunzio" University of Chieti-Pescara Chieti, Italy ; Aging Research Center (Ce.S.I.), "G. d'Annunzio" University Foundation Chieti, Italy
| | - Valentina Crocetta
- Department of Medical, Oral and Biotechnological Sciences, "G. d'Annunzio" University of Chieti-Pescara Chieti, Italy ; Aging Research Center (Ce.S.I.), "G. d'Annunzio" University Foundation Chieti, Italy
| | - Serena De Nicola
- Department of Medical, Oral and Biotechnological Sciences, "G. d'Annunzio" University of Chieti-Pescara Chieti, Italy ; Aging Research Center (Ce.S.I.), "G. d'Annunzio" University Foundation Chieti, Italy
| | - Fabio Verginelli
- Aging Research Center (Ce.S.I.), "G. d'Annunzio" University Foundation Chieti, Italy ; Department of Pharmacy, "G. d'Annunzio" University of Chieti-Pescara Chieti, Italy
| | | | - Giovanni Di Bonaventura
- Department of Medical, Oral and Biotechnological Sciences, "G. d'Annunzio" University of Chieti-Pescara Chieti, Italy ; Aging Research Center (Ce.S.I.), "G. d'Annunzio" University Foundation Chieti, Italy
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11
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Mendis N, Lin YR, Faucher SP. Comparison of virulence properties of Pseudomonas aeruginosa exposed to water and grown in rich broth. Can J Microbiol 2014; 60:777-81. [PMID: 25352257 DOI: 10.1139/cjm-2014-0519] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that can infect susceptible patients suffering from cystic fibrosis, immunosuppression, and severe burns. Nosocomial- and community-acquired infection is likely due to contact with water sources contaminated with P. aeruginosa. Most of what is known about the virulence properties of P. aeruginosa was derived from studies using fairly rich broths, which do not represent conditions found in water, such as low nutrient concentrations. Here, we compare biofilm production, invasion of epithelial cells, cytotoxicity, and pyocyanin production of P. aeruginosa in water with P. aeruginosa grown in rich broth. Since tap water is variable, we used a defined water medium, Fraquil, to ensure reproducibility of the results. We found that P. aeruginosa does not readily form biofilm in Fraquil. Pseudomonas aeruginosa is equally able to attach to and invade epithelial cells but is more cytotoxic after incubation in water for 30 days than when it is grown in rich broth. Moreover, P. aeruginosa produces less pyocyanin when exposed to water. Our results show that P. aeruginosa seems to have different properties when exposed to water than when grown in rich broth.
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Affiliation(s)
- Nilmini Mendis
- Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, Macdonald Campus, McGill University, 21 111 Lakeshore Road, Ste-Anne-de-Bellevue, QC H9X 3V9, Canada
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12
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Balasubramanian D, Kumari H, Jaric M, Fernandez M, Turner KH, Dove SL, Narasimhan G, Lory S, Mathee K. Deep sequencing analyses expands the Pseudomonas aeruginosa AmpR regulon to include small RNA-mediated regulation of iron acquisition, heat shock and oxidative stress response. Nucleic Acids Res 2014; 42:979-98. [PMID: 24157832 PMCID: PMC3902932 DOI: 10.1093/nar/gkt942] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2013] [Revised: 09/21/2013] [Accepted: 09/26/2013] [Indexed: 11/23/2022] Open
Abstract
Pathogenicity of Pseudomonas aeruginosa, a major cause of many acute and chronic human infections, is determined by tightly regulated expression of multiple virulence factors. Quorum sensing (QS) controls expression of many of these pathogenic determinants. Previous microarray studies have shown that the AmpC β-lactamase regulator AmpR, a member of the LysR family of transcription factors, also controls non-β-lactam resistance and multiple virulence mechanisms. Using RNA-Seq and complementary assays, this study further expands the AmpR regulon to include diverse processes such as oxidative stress, heat shock and iron uptake. Importantly, AmpR affects many of these phenotypes, in part, by regulating expression of non-coding RNAs such as rgP32, asRgsA, asPrrF1 and rgRsmZ. AmpR positively regulates expression of the major QS regulators LasR, RhlR and MvfR, and genes of the Pseudomonas quinolone system. Chromatin immunoprecipitation (ChIP)-Seq and ChIP-quantitative real-time polymerase chain reaction studies show that AmpR binds to the ampC promoter both in the absence and presence of β-lactams. In addition, AmpR directly binds the lasR promoter, encoding the QS master regulator. Comparison of the AmpR-binding sequences from the transcriptome and ChIP-Seq analyses identified an AT-rich consensus-binding motif. This study further attests to the role of AmpR in regulating virulence and physiological processes in P. aeruginosa.
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Affiliation(s)
- Deepak Balasubramanian
- Department of Biological Sciences, College of Arts and Science, Florida International University, Miami, FL 33199, USA, Department of Molecular Microbiology and Infectious Diseases, Herbert Wertheim College of Medicine, Florida International University, Miami, FL 33199, USA, BioRG, School of Computing and Information Science, College of Engineering and Computing, Florida International University, Miami, FL 33199, USA, Division of Infectious Diseases, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA and Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Hansi Kumari
- Department of Biological Sciences, College of Arts and Science, Florida International University, Miami, FL 33199, USA, Department of Molecular Microbiology and Infectious Diseases, Herbert Wertheim College of Medicine, Florida International University, Miami, FL 33199, USA, BioRG, School of Computing and Information Science, College of Engineering and Computing, Florida International University, Miami, FL 33199, USA, Division of Infectious Diseases, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA and Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Melita Jaric
- Department of Biological Sciences, College of Arts and Science, Florida International University, Miami, FL 33199, USA, Department of Molecular Microbiology and Infectious Diseases, Herbert Wertheim College of Medicine, Florida International University, Miami, FL 33199, USA, BioRG, School of Computing and Information Science, College of Engineering and Computing, Florida International University, Miami, FL 33199, USA, Division of Infectious Diseases, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA and Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Mitch Fernandez
- Department of Biological Sciences, College of Arts and Science, Florida International University, Miami, FL 33199, USA, Department of Molecular Microbiology and Infectious Diseases, Herbert Wertheim College of Medicine, Florida International University, Miami, FL 33199, USA, BioRG, School of Computing and Information Science, College of Engineering and Computing, Florida International University, Miami, FL 33199, USA, Division of Infectious Diseases, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA and Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Keith H. Turner
- Department of Biological Sciences, College of Arts and Science, Florida International University, Miami, FL 33199, USA, Department of Molecular Microbiology and Infectious Diseases, Herbert Wertheim College of Medicine, Florida International University, Miami, FL 33199, USA, BioRG, School of Computing and Information Science, College of Engineering and Computing, Florida International University, Miami, FL 33199, USA, Division of Infectious Diseases, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA and Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Simon L. Dove
- Department of Biological Sciences, College of Arts and Science, Florida International University, Miami, FL 33199, USA, Department of Molecular Microbiology and Infectious Diseases, Herbert Wertheim College of Medicine, Florida International University, Miami, FL 33199, USA, BioRG, School of Computing and Information Science, College of Engineering and Computing, Florida International University, Miami, FL 33199, USA, Division of Infectious Diseases, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA and Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Giri Narasimhan
- Department of Biological Sciences, College of Arts and Science, Florida International University, Miami, FL 33199, USA, Department of Molecular Microbiology and Infectious Diseases, Herbert Wertheim College of Medicine, Florida International University, Miami, FL 33199, USA, BioRG, School of Computing and Information Science, College of Engineering and Computing, Florida International University, Miami, FL 33199, USA, Division of Infectious Diseases, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA and Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Stephen Lory
- Department of Biological Sciences, College of Arts and Science, Florida International University, Miami, FL 33199, USA, Department of Molecular Microbiology and Infectious Diseases, Herbert Wertheim College of Medicine, Florida International University, Miami, FL 33199, USA, BioRG, School of Computing and Information Science, College of Engineering and Computing, Florida International University, Miami, FL 33199, USA, Division of Infectious Diseases, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA and Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Kalai Mathee
- Department of Biological Sciences, College of Arts and Science, Florida International University, Miami, FL 33199, USA, Department of Molecular Microbiology and Infectious Diseases, Herbert Wertheim College of Medicine, Florida International University, Miami, FL 33199, USA, BioRG, School of Computing and Information Science, College of Engineering and Computing, Florida International University, Miami, FL 33199, USA, Division of Infectious Diseases, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA and Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, USA
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13
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Daddaoua A, Fillet S, Fernández M, Udaondo Z, Krell T, Ramos JL. Genes for carbon metabolism and the ToxA virulence factor in Pseudomonas aeruginosa are regulated through molecular interactions of PtxR and PtxS. PLoS One 2012; 7:e39390. [PMID: 22844393 PMCID: PMC3402500 DOI: 10.1371/journal.pone.0039390] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Accepted: 05/21/2012] [Indexed: 11/19/2022] Open
Abstract
Homologs of the transcriptional regulator PtxS are omnipresent in Pseudomonas, whereas PtxR homologues are exclusively found in human pathogenic Pseudomonas species. In all Pseudomonas sp., PtxS with 2-ketogluconate is the regulator of the gluconate degradation pathway and controls expression from its own promoter and also from the P(gad) and P(kgu) for the catabolic operons. There is evidence that PtxS and PtxR play a central role in the regulation of exotoxin A expression, a relevant primary virulence factor of Pseudomonas aeruginosa. We show using DNaseI-footprint analysis that in P. aeruginosa PtxR binds to the -35 region of the P(toxA) promoter in front of the exotoxin A gene, whereas PtxS does not bind to this promoter. Bioinformatic and DNaseI-footprint analysis identified a PtxR binding site in the P(kgu) and P(gad) promoters that overlaps the -35 region, while the PtxS operator site is located 50 bp downstream from the PtxR site. In vitro, PtxS recognises PtxR with nanomolar affinity, but this interaction does not occur in the presence of 2-ketogluconate, the specific effector of PtxS. DNAaseI footprint assays of P(kgu) and P(gad) promoters with PtxS and PtxR showed a strong region of hyper-reactivity between both regulator binding sites, indicative of DNA distortion when both proteins are bound; however in the presence of 2-ketogluconate no protection was observed. We conclude that PtxS modulates PtxR activity in response to 2-ketogluconate by complex formation in solution in the case of the P(toxA) promoter, or via the formation of a DNA loop as in the regulation of gluconate catabolic genes. Data suggest two different mechanisms of control exerted by the same regulator.
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Affiliation(s)
| | - Sandy Fillet
- Department of Environmental Protection, CSIC-EEZ, Granada, Spain
| | | | - Zulema Udaondo
- Department of Environmental Protection, CSIC-EEZ, Granada, Spain
| | - Tino Krell
- Department of Environmental Protection, CSIC-EEZ, Granada, Spain
| | - Juan L. Ramos
- Department of Environmental Protection, CSIC-EEZ, Granada, Spain
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14
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Carrión VJ, Arrebola E, Cazorla FM, Murillo J, de Vicente A. The mbo operon is specific and essential for biosynthesis of mangotoxin in Pseudomonas syringae. PLoS One 2012; 7:e36709. [PMID: 22615797 PMCID: PMC3355146 DOI: 10.1371/journal.pone.0036709] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2012] [Accepted: 04/05/2012] [Indexed: 12/31/2022] Open
Abstract
Mangotoxin is an antimetabolite toxin produced by certain Pseudomonas syringae pv. syringae strains. This toxin is an oligopeptide that inhibits ornithine N-acetyl transferase, a key enzyme in the biosynthesis of ornithine and arginine. Previous studies have reported the involvement of the putative nonribosomal peptide synthetase MgoA in virulence and mangotoxin production. In this study, we analyse a new chromosomal region of P. syringae pv. syringae UMAF0158, which contains six coding sequences arranged as an operon (mbo operon). The mbo operon was detected in only mangotoxin-producing strains, and it was shown to be essential for the biosynthesis of this toxin. Mutants in each of the six ORFs of the mbo operon were partially or completely impaired in the production of the toxin. In addition, Pseudomonas spp. mangotoxin non-producer strains transformed with the mbo operon gained the ability to produce mangotoxin, indicating that this operon contains all the genetic information necessary for mangotoxin biosynthesis. The generation of a single transcript for the mbo operon was confirmed and supported by the allocation of a unique promoter and Rho-independent terminator. The phylogenetic analysis of the P. syringae strains harbouring the mbo operon revealed that these strains clustered together.
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Affiliation(s)
- Víctor J. Carrión
- Instituto de Hortofruticultura Subtropical y Mediterránea “La Mayora” (IHSM-UMA-CSIC), Departamento de Microbiología, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain
| | - Eva Arrebola
- Instituto de Hortofruticultura Subtropical y Mediterránea “La Mayora” (IHSM-UMA-CSIC), Estación Experimental La Mayora, Málaga, Spain
| | - Francisco M. Cazorla
- Instituto de Hortofruticultura Subtropical y Mediterránea “La Mayora” (IHSM-UMA-CSIC), Departamento de Microbiología, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain
| | - Jesús Murillo
- Laboratorio de Patología Vegetal, ETS de Ingenieros Agrónomos, Universidad Pública de Navarra, Pamplona, Spain
| | - Antonio de Vicente
- Instituto de Hortofruticultura Subtropical y Mediterránea “La Mayora” (IHSM-UMA-CSIC), Departamento de Microbiología, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain
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15
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Blier AS, Veron W, Bazire A, Gerault E, Taupin L, Vieillard J, Rehel K, Dufour A, Le Derf F, Orange N, Hulen C, Feuilloley MGJ, Lesouhaitier O. C-type natriuretic peptide modulates quorum sensing molecule and toxin production in Pseudomonas aeruginosa. MICROBIOLOGY (READING, ENGLAND) 2011; 157:1929-1944. [PMID: 21511763 PMCID: PMC3755537 DOI: 10.1099/mic.0.046755-0] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/10/2010] [Revised: 04/14/2011] [Accepted: 04/18/2011] [Indexed: 12/27/2022]
Abstract
Pseudomonas aeruginosa coordinates its virulence expression and establishment in the host in response to modification of its environment. During the infectious process, bacteria are exposed to and can detect eukaryotic products including hormones. It has been shown that P. aeruginosa is sensitive to natriuretic peptides, a family of eukaryotic hormones, through a cyclic nucleotide-dependent sensor system that modulates its cytotoxicity. We observed that pre-treatment of P. aeruginosa PAO1 with C-type natriuretic peptide (CNP) increases the capacity of the bacteria to kill Caenorhabditis elegans through diffusive toxin production. In contrast, brain natriuretic peptide (BNP) did not affect the capacity of the bacteria to kill C. elegans. The bacterial production of hydrogen cyanide (HCN) was enhanced by both BNP and CNP whereas the production of phenazine pyocyanin was strongly inhibited by CNP. The amount of 2-heptyl-4-quinolone (HHQ), a precursor to 2-heptyl-3-hydroxyl-4-quinolone (Pseudomonas quinolone signal; PQS), decreased after CNP treatment. The quantity of 2-nonyl-4-quinolone (HNQ), another quinolone which is synthesized from HHQ, was also reduced after CNP treatment. Conversely, both BNP and CNP significantly enhanced bacterial production of acylhomoserine lactone (AHL) [e.g. 3-oxo-dodecanoyl-homoserine lactone (3OC12-HSL) and butanoylhomoserine lactone (C4-HSL)]. These results correlate with an induction of lasI transcription 1 h after bacterial exposure to BNP or CNP. Concurrently, pre-treatment of P. aeruginosa PAO1 with either BNP or CNP enhanced PAO1 exotoxin A production, via a higher toxA mRNA level. At the same time, CNP led to elevated amounts of algC mRNA, indicating that algC is involved in C. elegans killing. Finally, we observed that in PAO1, Vfr protein is essential to the pro-virulent effect of CNP whereas the regulator PtxR supports only a part of the CNP pro-virulent activity. Taken together, these data reinforce the hypothesis that during infection natriuretic peptides, particularly CNP, could enhance the virulence of PAO1. This activity is relayed by Vfr and PtxR activation, and a general diagram of the virulence activation cascade involving AHL, HCN and exotoxin A is proposed.
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Affiliation(s)
- Anne-Sophie Blier
- Laboratory of Cold Microbiology – Signals and Micro-environment EA 4312, University of Rouen, 55 Rue Saint Germain, 27000 Evreux, France
| | - Wilfried Veron
- Laboratory of Cold Microbiology – Signals and Micro-environment EA 4312, University of Rouen, 55 Rue Saint Germain, 27000 Evreux, France
| | - Alexis Bazire
- Laboratoire de Biotechnologie et Chimie Marines, Université de Bretagne-Sud B.P. 92116, 56321 Lorient Cedex, France
| | - Eloïse Gerault
- Laboratory of Cold Microbiology – Signals and Micro-environment EA 4312, University of Rouen, 55 Rue Saint Germain, 27000 Evreux, France
| | - Laure Taupin
- Laboratoire de Biotechnologie et Chimie Marines, Université de Bretagne-Sud B.P. 92116, 56321 Lorient Cedex, France
| | | | - Karine Rehel
- Laboratoire de Biotechnologie et Chimie Marines, Université de Bretagne-Sud B.P. 92116, 56321 Lorient Cedex, France
| | - Alain Dufour
- Laboratoire de Biotechnologie et Chimie Marines, Université de Bretagne-Sud B.P. 92116, 56321 Lorient Cedex, France
| | - Franck Le Derf
- SIMA, UMR 6014 COBRA, University of Rouen, 27000 Evreux, France
| | - Nicole Orange
- Laboratory of Cold Microbiology – Signals and Micro-environment EA 4312, University of Rouen, 55 Rue Saint Germain, 27000 Evreux, France
| | - Christian Hulen
- Laboratory of Cold Microbiology – Signals and Micro-environment EA 4312, University of Rouen, 55 Rue Saint Germain, 27000 Evreux, France
| | - Marc G. J. Feuilloley
- Laboratory of Cold Microbiology – Signals and Micro-environment EA 4312, University of Rouen, 55 Rue Saint Germain, 27000 Evreux, France
| | - Olivier Lesouhaitier
- Laboratory of Cold Microbiology – Signals and Micro-environment EA 4312, University of Rouen, 55 Rue Saint Germain, 27000 Evreux, France
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16
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Fuchs EL, Brutinel ED, Klem ER, Fehr AR, Yahr TL, Wolfgang MC. In vitro and in vivo characterization of the Pseudomonas aeruginosa cyclic AMP (cAMP) phosphodiesterase CpdA, required for cAMP homeostasis and virulence factor regulation. J Bacteriol 2010; 192:2779-90. [PMID: 20348254 PMCID: PMC2876501 DOI: 10.1128/jb.00168-10] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2010] [Accepted: 03/16/2010] [Indexed: 12/19/2022] Open
Abstract
Cyclic AMP (cAMP) is an important second messenger signaling molecule that controls a wide variety of eukaryotic and prokaryotic responses to extracellular cues. For cAMP-dependent signaling pathways to be effective, the intracellular cAMP concentration is tightly controlled at the level of synthesis and degradation. In the opportunistic human pathogen Pseudomonas aeruginosa, cAMP is a key regulator of virulence gene expression. To better understand the role of cAMP homeostasis in this organism, we identified and characterized the enzyme CpdA, a putative cAMP phosphodiesterase. We demonstrate that CpdA possesses 3',5'-cAMP phosphodiesterase activity in vitro and that it utilizes an iron-dependent catalytic mechanism. Deletion of cpdA results in the accumulation of intracellular cAMP and altered regulation of P. aeruginosa virulence traits. Further, we demonstrate that the cAMP-dependent transcription factor Vfr directly regulates cpdA expression in response to intracellular cAMP accumulation, thus providing a feedback mechanism for controlling cAMP levels and fine-tuning virulence factor expression.
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Affiliation(s)
- Erin L. Fuchs
- Cystic Fibrosis/Pulmonary Research and Treatment Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, Department of Microbiology, University of Iowa, Iowa City, Iowa 52242, Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | - Evan D. Brutinel
- Cystic Fibrosis/Pulmonary Research and Treatment Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, Department of Microbiology, University of Iowa, Iowa City, Iowa 52242, Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | - Erich R. Klem
- Cystic Fibrosis/Pulmonary Research and Treatment Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, Department of Microbiology, University of Iowa, Iowa City, Iowa 52242, Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | - Anthony R. Fehr
- Cystic Fibrosis/Pulmonary Research and Treatment Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, Department of Microbiology, University of Iowa, Iowa City, Iowa 52242, Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | - Timothy L. Yahr
- Cystic Fibrosis/Pulmonary Research and Treatment Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, Department of Microbiology, University of Iowa, Iowa City, Iowa 52242, Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | - Matthew C. Wolfgang
- Cystic Fibrosis/Pulmonary Research and Treatment Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, Department of Microbiology, University of Iowa, Iowa City, Iowa 52242, Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
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17
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The Pseudomonas aeruginosa Vfr regulator controls global virulence factor expression through cyclic AMP-dependent and -independent mechanisms. J Bacteriol 2010; 192:3553-64. [PMID: 20494996 DOI: 10.1128/jb.00363-10] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Vfr is a global regulator of virulence factor expression in the human pathogen Pseudomonas aeruginosa. Although indirect evidence suggests that Vfr activity is controlled by cyclic AMP (cAMP), it has been hypothesized that the putative cAMP binding pocket of Vfr may accommodate additional cyclic nucleotides. In this study, we used two different approaches to generate apo-Vfr and examined its ability to bind a representative set of virulence gene promoters in the absence and presence of different allosteric effectors. Of the cyclic nucleotides tested, only cAMP was able to restore DNA binding activity to apo-Vfr. In contrast, cGMP was capable of inhibiting cAMP-Vfr DNA binding. Further, we demonstrate that vfr expression is autoregulated and cAMP dependent and involves Vfr binding to a previously unidentified site within the vfr promoter region. Using a combination of in vitro and in vivo approaches, we show that cAMP is required for Vfr-dependent regulation of a specific subset of virulence genes. In contrast, we discovered that Vfr controls expression of the lasR promoter in a cAMP-independent manner. In summary, our data support a model in which Vfr controls virulence gene expression by distinct (cAMP-dependent and -independent) mechanisms, which may allow P. aeruginosa to fine-tune its virulence program in response to specific host cues or environments.
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18
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Rojo F. Carbon catabolite repression in Pseudomonas : optimizing metabolic versatility and interactions with the environment. FEMS Microbiol Rev 2010; 34:658-84. [PMID: 20412307 DOI: 10.1111/j.1574-6976.2010.00218.x] [Citation(s) in RCA: 356] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Metabolically versatile free-living bacteria have global regulation systems that allow cells to selectively assimilate a preferred compound among a mixture of several potential carbon sources. This process is known as carbon catabolite repression (CCR). CCR optimizes metabolism, improving the ability of bacteria to compete in their natural habitats. This review summarizes the regulatory mechanisms responsible for CCR in the bacteria of the genus Pseudomonas, which can live in many different habitats. Although the information available is still limited, the molecular mechanisms responsible for CCR in Pseudomonas are clearly different from those of Enterobacteriaceae or Firmicutes. An understanding of the molecular mechanisms underlying CCR is important to know how metabolism is regulated and how bacteria degrade compounds in the environment. This is particularly relevant for compounds that are degraded slowly and accumulate, creating environmental problems. CCR has a major impact on the genes involved in the transport and metabolism of nonpreferred carbon sources, but also affects the expression of virulence factors in several bacterial species, genes that are frequently directed to allow the bacterium to gain access to new sources of nutrients. Finally, CCR has implications in the optimization of biotechnological processes such as biotransformations or bioremediation strategies.
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Affiliation(s)
- Fernando Rojo
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, CSIC, Madrid, Spain.
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