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Soto-Aceves MP, Smalley NE, Schaefer AL, Greenberg EP. The Relationship of pqs Gene Expression to Acylhomoserine Lactone Signaling in Pseudomonas aeruginosa. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.22.586172. [PMID: 38562759 PMCID: PMC10983942 DOI: 10.1101/2024.03.22.586172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
The opportunistic pathogen Pseudomonas aeruginosa has complex quorum sensing (QS) circuitry, which involves two acylhomoserine lactone (AHL) systems, the LasI AHL synthase and LasR AHL-dependent transcriptional activator system and the RhlI AHL synthase-RhlR AHL-responsive transcriptional activator. There is also a quinoline signaling system (the Pseudomonas quinolone signal, PQS, system). Although there is a core set of genes regulated by the AHL circuits, there is substantial strain-to-strain variation in the non-core QS regulated genes. Reductive evolution of the QS regulon, and variation in specific genes activated by QS, occurs in laboratory evolution experiments with the model strain PAO1. We used a transcriptomics approach to test the hypothesis that reductive evolution in the PAO1 QS regulon can in large part be explained by a simple null mutation in pqsR , the gene encoding the transcriptional activator of the pqs operon. We found that PqsR had very little influence on the AHL QS regulon. This was a surprising finding because the last gene in the PqsR-dependent pqs operon, pqsE , codes for a protein, which physically interacts with RhlR and this interaction is required for RhlR-dependent activation of some genes. We used comparative transcriptomics to examine the influence of a pqsE mutation on the QS regulon and identified only three transcripts, which were strictly dependent on PqsE. By using reporter constructs we showed that the PqsE influence on other genes was dependent on experimental conditions and we have gained some insight about those conditions. This work adds to our understanding of the plasticity of the P. aeruginosa QS regulon and to the role PqsE plays in RhlR-dependent gene activation.
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2
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Trottier MC, de Oliveira Pereira T, Groleau MC, Hoffman LR, Dandekar AA, Déziel E. The end of the reign of a "master regulator''? A defect in function of the LasR quorum sensing regulator is a common feature of Pseudomonas aeruginosa isolates. mBio 2024; 15:e0237623. [PMID: 38315035 PMCID: PMC10936206 DOI: 10.1128/mbio.02376-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2024] Open
Abstract
Pseudomonas aeruginosa, a bacterium causing infections in immunocompromised individuals, regulates several of its virulence functions using three interlinked quorum sensing (QS) systems (las, rhl, and pqs). Despite its presumed importance in regulating virulence, dysfunction of the las system regulator LasR occurs frequently in strains isolated from various environments, including clinical infections. This newfound abundance of LasR-defective strains calls into question existing hypotheses regarding their selection. Indeed, current assumptions concerning factors driving the emergence of LasR-deficient isolates and the role of LasR in the QS hierarchy must be reconsidered. Here, we propose that LasR is not the primary master regulator of QS in all P. aeruginosa genetic backgrounds, even though it remains ecologically significant. We also revisit and complement current knowledge on the ecology of LasR-dependent QS in P. aeruginosa, discuss the hypotheses explaining the putative adaptive benefits of selecting against LasR function, and consider the implications of this renewed understanding.
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Affiliation(s)
- Mylène C. Trottier
- Centre Armand-Frappier Santé Biotechnologie, Institut National de la Recherche Scientifique (INRS), Laval, Québec, Canada
| | - Thays de Oliveira Pereira
- Centre Armand-Frappier Santé Biotechnologie, Institut National de la Recherche Scientifique (INRS), Laval, Québec, Canada
| | - Marie-Christine Groleau
- Centre Armand-Frappier Santé Biotechnologie, Institut National de la Recherche Scientifique (INRS), Laval, Québec, Canada
| | - Lucas R. Hoffman
- Departments of Pediatrics and Microbiology, University of Washington, Seattle, Washington, USA
| | - Ajai A. Dandekar
- Departments of Medicine and Microbiology, University of Washington, Seattle, Washington, USA
| | - Eric Déziel
- Centre Armand-Frappier Santé Biotechnologie, Institut National de la Recherche Scientifique (INRS), Laval, Québec, Canada
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3
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Mohamed SA, Mahmoud HE, Embaby AM, Haroun M, Sabra SA. Lactoferrin/pectin nanocomplex encapsulating ciprofloxacin and naringin as a lung targeting antibacterial nanoplatform with oxidative stress alleviating effect. Int J Biol Macromol 2024; 261:129842. [PMID: 38309386 DOI: 10.1016/j.ijbiomac.2024.129842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 01/12/2024] [Accepted: 01/27/2024] [Indexed: 02/05/2024]
Abstract
Pseudomonas aeruginosa is an opportunistic Gram-negative bacterium with adaptive metabolic abilities. It can cause hospital-acquired infections with significant mortality rates, particularly in people with already existing medical conditions. Its ability to develop resistance to common antibiotics makes managing this type of infections very challenging. Furthermore, oxidative stress is a common consequence of bacterial infection and antibiotic therapy, due to formation of reactive oxygen species (ROS) during their mode of action. In this study we aimed to alleviate oxidative stress and enhance the antibacterial efficacy of ciprofloxacin (CPR) antibiotic by its co-encapsulation with naringin (NAR) within a polyelectrolyte complex (PEX). The PEX comprised of polycationic lactoferrin (LF) and polyanionic pectin (PEC). CPR/NAR-loaded PEX exhibited spherical shape with particle size of 237 ± 3.5 nm, negatively charged zeta potential (-23 ± 2.2 mV) and EE% of 61.2 ± 4.9 for CPR and 76.2 ± 3.4 % for NAR. The LF/PEC complex showed prolonged sequential release profile of CPR to limit bacterial expansion, followed by slow liberation of NAR, which mitigates excess ROS produced by CPR's mechanism of action without affecting its efficacy. Interestingly, this PEX demonstrated good hemocompatibility with no significant in vivo toxicity regarding hepatic and renal functions. In addition, infected mice administrated this nanoplatform intravenously exhibited significant CFU reduction in the lungs and kidneys, along with reduced immunoreactivity against myeloperoxidase. Moreover, this PEX was found to reduce the lungs´ oxidative stress via increasing both glutathione (GSH) and catalase (CAT) levels while lowering malondialdehyde (MDA). In conclusion, CPR/NAR-loaded PEX can offer a promising targeted lung delivery strategy while enhancing the therapeutic outcomes of CPR with reduced oxidative stress.
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Affiliation(s)
- Shaymaa A Mohamed
- Department of Biotechnology, Institute of Graduate Studies and Research, Alexandria University, Alexandria 21526, Egypt
| | - Hoda E Mahmoud
- Department of Biotechnology, Institute of Graduate Studies and Research, Alexandria University, Alexandria 21526, Egypt
| | - Amira M Embaby
- Department of Biotechnology, Institute of Graduate Studies and Research, Alexandria University, Alexandria 21526, Egypt
| | - Medhat Haroun
- Department of Biotechnology, Institute of Graduate Studies and Research, Alexandria University, Alexandria 21526, Egypt
| | - Sally A Sabra
- Department of Biotechnology, Institute of Graduate Studies and Research, Alexandria University, Alexandria 21526, Egypt.
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4
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Muriel-Millán LF, Montelongo-Martínez LF, González-Valdez A, Bedoya-Pérez LP, Cocotl-Yañez M, Soberón-Chávez G. The alternative sigma factor RpoS regulates Pseudomonas aeruginosa quorum sensing response by repressing the pqsABCDE operon and activating vfr. Mol Microbiol 2024; 121:291-303. [PMID: 38169053 DOI: 10.1111/mmi.15224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 12/02/2023] [Accepted: 12/22/2023] [Indexed: 01/05/2024]
Abstract
Pseudomonas aeruginosa is an important opportunistic pathogen. Several of its virulence-related processes, including the synthesis of pyocyanin (PYO) and biofilm formation, are controlled by quorum sensing (QS). It has been shown that the alternative sigma factor RpoS regulates QS through the reduction of lasR and rhlR transcription (encoding QS regulators). However, paradoxically, the absence of RpoS increases PYO production and biofilm development (that are RhlR dependent) by unknown mechanisms. Here, we show that RpoS represses pqsE transcription, which impacts the stability and activity of RhlR. In the absence of RpoS, rhlR transcript levels are reduced but not the RhlR protein concentration, presumably by its stabilization by PqsE, whose expression is increased. We also report that PYO synthesis and the expression of pqsE and phzA1B1C1D1E1F1G1 operon exhibit the same pattern at different RpoS concentrations, suggesting that the RpoS-dependent PYO production is due to its ability to modify PqsE concentration, which in turn modulates the activation of the phzA1 promoter by RhlR. Finally, we demonstrate that RpoS favors the expression of Vfr, which activates the transcription of lasR and rhlR. Our study contributes to the understanding of how RpoS modulates the QS response in P. aeruginosa, exerting both negative and positive regulation.
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Affiliation(s)
- Luis Felipe Muriel-Millán
- Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, Ciudad de México, Mexico
| | - Luis Fernando Montelongo-Martínez
- Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, Ciudad de México, Mexico
| | - Abigail González-Valdez
- Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, Ciudad de México, Mexico
| | - Leidy Patricia Bedoya-Pérez
- Programa de Biología Sintética, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico
| | - Miguel Cocotl-Yañez
- Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad Universitaria, Ciudad de México, Mexico
| | - Gloria Soberón-Chávez
- Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, Ciudad de México, Mexico
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5
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Sultan M, Arya R, Chaurasia AK, Kim KK. Sensor histidine kinases kdpD and aauS regulate biofilm and virulence in Pseudomonas aeruginosa PA14. Front Cell Infect Microbiol 2023; 13:1270667. [PMID: 37881370 PMCID: PMC10595159 DOI: 10.3389/fcimb.2023.1270667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 09/25/2023] [Indexed: 10/27/2023] Open
Abstract
Pseudomonas aeruginosa is a multidrug-resistant opportunistic human pathogen that utilizes two-component systems (TCSs) to sense pathophysiological signals and coordinate virulence. P. aeruginosa contains 64 sensor histidine kinases (HKs) and 72 response regulators (RRs) that play important roles in metabolism, bacterial physiology, and virulence. However, the role of some TCSs in virulence remains uncharacterized. In this study, we evaluated the virulence potential of some uncharacterized sensor HK and RR knockouts in P. aeruginosa using a Galleria mellonella infection model. Furthermore, we demonstrated that KdpD and AauS HKs regulate virulence by affecting P. aeruginosa biofilm formation and motility. Both ΔkdpD and ΔaauS showed reduced biofilm and motility which were confirmed by restored phenotypes upon complementation. Moreover, ΔkdpD and ΔaauS exhibited increased survival of HeLa cells and G. mellonella during in vivo infection. Altered expression of the transcriptional regulators anR and lasR, along with the virulence genes lasA, pelA, cupA, pqsA, pqsB, pqsC, and pqsD in the mutant strains elucidated the mechanism by which ΔkdpD and ΔaauS affect virulence. These findings confirm that kdpD and aauS play important roles in P. aeruginosa pathogenesis by regulating biofilm formation and motility.
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Affiliation(s)
- Maria Sultan
- Department of Precision Medicine, Graduate School of Basic Medical Science, Institute for Antimicrobial Resistance Research and Therapeutics, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| | - Rekha Arya
- Department of Precision Medicine, Graduate School of Basic Medical Science, Institute for Antimicrobial Resistance Research and Therapeutics, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
- Department of Orthopedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Akhilesh Kumar Chaurasia
- Department of Precision Medicine, Graduate School of Basic Medical Science, Institute for Antimicrobial Resistance Research and Therapeutics, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| | - Kyeong Kyu Kim
- Department of Precision Medicine, Graduate School of Basic Medical Science, Institute for Antimicrobial Resistance Research and Therapeutics, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
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Quiroz-Morales SE, Muriel-Millán LF, Ponce-Soto GY, González-Valdez A, Castillo-Juárez I, Servín-González L, Soberón-Chávez G. Pseudomonas aeruginosa strains belonging to phylogroup 3 frequently exhibit an atypical quorum sensing response: the case of MAZ105, a tomato rhizosphere isolate. MICROBIOLOGY (READING, ENGLAND) 2023; 169:001401. [PMID: 37819040 PMCID: PMC10634362 DOI: 10.1099/mic.0.001401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Accepted: 10/03/2023] [Indexed: 10/13/2023]
Abstract
Pseudomonas aeruginosa is a widespread γ-proteobacterium and an important opportunistic pathogen. The genetically diverse P. aeruginosa phylogroup 3 strains are characterized by producing the pore-forming ExlA toxin and by their lack of a type III secretion system. However, like all strains of this species, they produce several virulence-associated traits, such as elastase, rhamnolipids and pyocyanin, which are regulated by quorum sensing (QS). The P. aeruginosa QS response comprises three systems (Las, Rhl and Pqs, respectively) that hierarchically regulate these virulence factors. The Pqs QS system is composed of the PqsR transcriptional factor, which, coupled with the alkyl-quinolones HHQ or PQS, activates the transcription of the pqsABCDE operon. The products of the first four genes of this operon produce HHQ, which is then converted to PQS by PqsH, while PqsE forms a complex with RhlR and stabilizes it. In this study we report that mutations affecting the Pqs system are particularly common in phylogroup 3 strains. To better understand QS in phylogroup 3 strains we studied strain MAZ105 isolated from tomato rhizosphere and showed that it contains mutations in the central QS transcriptional regulator, LasR, and in the gene encoding the PqsA enzyme involved in the synthesis of PQS. However, it can still produce QS-regulated virulence factors and is virulent in Galleria mellonella and mildly pathogenic in the mouse abscess/necrosis model; our results show that this may be due to the expression of pqsE from a different PqsR-independent promoter than the pqsA promoter. Our results indicate that using anti-virulence therapy based on targeting the PQS system will not be effective against infections by P. aeruginosa phylogroup 3 strains.
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Affiliation(s)
- Sara E. Quiroz-Morales
- Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, Apdo, Postal 70228, C. P. 04510, CDMX, Mexico
| | - Luis Felipe Muriel-Millán
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Col. Chamilpa, Cuernavaca, Morelos CP 62210, Mexico
| | - Gabriel Y. Ponce-Soto
- Microbial Paleogenomics Unit, Department of Genomes and Genetics, Pasteur Institute, 75015 Paris, France
| | - Abigail González-Valdez
- Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, Apdo, Postal 70228, C. P. 04510, CDMX, Mexico
| | - Israel Castillo-Juárez
- Laboratorio de Investigación y Aplicación de Fitoquímicos Bioactivos, Colegio de Postgraduados, 56230, Campus Montecillo, Texcoco, Mexico
| | - Luis Servín-González
- Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, Apdo, Postal 70228, C. P. 04510, CDMX, Mexico
| | - Gloria Soberón-Chávez
- Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, Apdo, Postal 70228, C. P. 04510, CDMX, Mexico
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7
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Peterson ND, Tse SY, Huang QJ, Wani KA, Schiffer CA, Pukkila-Worley R. Non-canonical pattern recognition of a pathogen-derived metabolite by a nuclear hormone receptor identifies virulent bacteria in C. elegans. Immunity 2023; 56:768-782.e9. [PMID: 36804958 PMCID: PMC10101930 DOI: 10.1016/j.immuni.2023.01.027] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 11/27/2022] [Accepted: 01/25/2023] [Indexed: 02/19/2023]
Abstract
Distinguishing infectious pathogens from harmless microorganisms is essential for animal health. The mechanisms used to identify infectious microbes are not fully understood, particularly in metazoan hosts that eat bacteria as their food source. Here, we characterized a non-canonical pattern-recognition system in Caenorhabditis elegans (C. elegans) that assesses the relative threat of virulent Pseudomonas aeruginosa (P. aeruginosa) to activate innate immunity. We discovered that the innate immune response in C. elegans was triggered by phenazine-1-carboxamide (PCN), a toxic metabolite produced by pathogenic strains of P. aeruginosa. We identified the nuclear hormone receptor NHR-86/HNF4 as the PCN sensor in C. elegans and validated that PCN bound to the ligand-binding domain of NHR-86/HNF4. Activation of NHR-86/HNF4 by PCN directly engaged a transcriptional program in intestinal epithelial cells that protected against P. aeruginosa. Thus, a bacterial metabolite is a pattern of pathogenesis surveilled by nematodes to identify a pathogen in its bacterial diet.
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Affiliation(s)
- Nicholas D Peterson
- Program in Innate Immunity, Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Samantha Y Tse
- Program in Innate Immunity, Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Qiuyu Judy Huang
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Khursheed A Wani
- Program in Innate Immunity, Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Celia A Schiffer
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Read Pukkila-Worley
- Program in Innate Immunity, Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Chan Medical School, Worcester, MA, USA.
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8
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Montelongo-Martínez LF, Hernández-Méndez C, Muriel-Millan LF, Hernández-Estrada R, Fabian-Del Olmo MJ, González-Valdez A, Soberón-Chávez G, Cocotl-Yañez M. Unraveling the regulation of pyocyanin synthesis by RsmA through MvaU and RpoS in Pseudomonas aeruginosa ID4365. J Basic Microbiol 2023; 63:51-63. [PMID: 36207285 DOI: 10.1002/jobm.202200432] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 09/05/2022] [Accepted: 09/18/2022] [Indexed: 01/04/2023]
Abstract
Pyocyanin is a phenazine with redox activity produced by Pseudomonas aeruginosa that is harmful to other bacteria and eukaryotic organisms by generating reactive oxygen species. Gene regulation of pyocyanin synthesis has been addressed in the PAO1 and PA14 strains and involves the three-quorum sensing systems Las, Rhl, and Pqs; the regulators RsaL, MvaU, and RpoS, and the posttranscriptional Rsm system, among others. Here, we determined how RsmA regulates pyocyanin synthesis in P. aeruginosa ID4365, an overproducer strain. We found that, in the protease peptone glucose ammonium salts medium, rsmA inactivation increases pyocyanin production compared with the wild-type strains ID4365, PAO, and PA14. We showed that RsmA regulates inversely the expression of both phz operons involved in pyocyanin synthesis; particularly the phz2 operon is positively regulated at the transcriptional level indirectly through MvaU. In addition, we found that the phz1 operon contributes mainly to pyocyanin synthesis and that RsmA negatively regulates phzM and phzS expression. Finally, we showed that translation of the sigma factor RpoS is positively regulated by RsmA, and the expression of rpoS under an independent promoter decreases pyocyanin production in the IDrsmA strain. These results indicate that RsmA regulates not only the genes for pyocyanin production but also their regulators.
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Affiliation(s)
- Luis F Montelongo-Martínez
- Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, México City, México
| | - Cristina Hernández-Méndez
- Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, México City, México
| | - Luis F Muriel-Millan
- Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México City, México
| | - René Hernández-Estrada
- Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, México City, México
| | - Misael J Fabian-Del Olmo
- Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, México City, México
| | - Abigail González-Valdez
- Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México City, México
| | - Gloria Soberón-Chávez
- Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México City, México
| | - Miguel Cocotl-Yañez
- Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, México City, México
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9
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O'Connor K, Zhao CY, Mei M, Diggle SP. Frequency of quorum-sensing mutations in Pseudomonas aeruginosa strains isolated from different environments. MICROBIOLOGY (READING, ENGLAND) 2022; 168. [PMID: 36748632 DOI: 10.1099/mic.0.001265] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Pseudomonas aeruginosa uses quorum sensing (QS) to coordinate the expression of multiple genes necessary for establishing and maintaining infection. It has previously been shown that lasR QS mutations frequently arise in cystic fibrosis (CF) lung infections, however, there has been far less emphasis on determining whether other QS system mutations arise during infection or in other environments. To test this, we utilized 852 publicly available sequenced P. aeruginosa genomes from the Pseudomonas International Consortium Database (IPCD) to study P. aeruginosa QS mutational signatures. To study isolates by source, we focused on a subset of 654 isolates collected from CF, wounds, and non-infection environmental isolates, where we could clearly identify their source. We also worked with a small collection of isolates in vitro to determine the impact of lasR and pqs mutations on isolate phenotypes. We found that lasR mutations are common across all environments and are not specific to infection nor a particular infection type. We also found that the pqs system proteins PqsA, PqsH, PqsL and MexT, a protein of increasing importance to the QS field, are highly variable. Conversely, RsaL, a negative transcriptional regulator of the las system, was found to be highly conserved, suggesting selective pressure to repress las system activity. Overall, our findings suggest that QS mutations in P. aeruginosa are common and not limited to the las system; however, LasR is unique in the frequency of putative loss-of-function mutations.
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Affiliation(s)
- Kathleen O'Connor
- Center for Microbial Dynamics & Infection, School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Conan Y Zhao
- Center for Microbial Dynamics & Infection, School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Madeline Mei
- Center for Microbial Dynamics & Infection, School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Stephen P Diggle
- Center for Microbial Dynamics & Infection, School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
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10
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Borgert SR, Henke S, Witzgall F, Schmelz S, Zur Lage S, Hotop SK, Stephen S, Lübken D, Krüger J, Gomez NO, van Ham M, Jänsch L, Kalesse M, Pich A, Brönstrup M, Häussler S, Blankenfeldt W. Moonlighting chaperone activity of the enzyme PqsE contributes to RhlR-controlled virulence of Pseudomonas aeruginosa. Nat Commun 2022; 13:7402. [PMID: 36456567 PMCID: PMC9715718 DOI: 10.1038/s41467-022-35030-w] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 11/14/2022] [Indexed: 12/05/2022] Open
Abstract
Pseudomonas aeruginosa is a major cause of nosocomial infections and also leads to severe exacerbations in cystic fibrosis or chronic obstructive pulmonary disease. Three intertwined quorum sensing systems control virulence of P. aeruginosa, with the rhl circuit playing the leading role in late and chronic infections. The majority of traits controlled by rhl transcription factor RhlR depend on PqsE, a dispensable thioesterase in Pseudomonas Quinolone Signal (PQS) biosynthesis that interferes with RhlR through an enigmatic mechanism likely involving direct interaction of both proteins. Here we show that PqsE and RhlR form a 2:2 protein complex that, together with RhlR agonist N-butanoyl-L-homoserine lactone (C4-HSL), solubilizes RhlR and thereby renders the otherwise insoluble transcription factor active. We determine crystal structures of the complex and identify residues essential for the interaction. To corroborate the chaperone-like activity of PqsE, we design stability-optimized variants of RhlR that bypass the need for C4-HSL and PqsE in activating PqsE/RhlR-controlled processes of P. aeruginosa. Together, our data provide insight into the unique regulatory role of PqsE and lay groundwork for developing new P. aeruginosa-specific pharmaceuticals.
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Affiliation(s)
- Sebastian Roman Borgert
- Department Structure and Function of Proteins, Helmholtz Centre for Infection Research, Inhoffenstr. 7, 38124, Braunschweig, Germany
| | - Steffi Henke
- Department Structure and Function of Proteins, Helmholtz Centre for Infection Research, Inhoffenstr. 7, 38124, Braunschweig, Germany
| | - Florian Witzgall
- Department Structure and Function of Proteins, Helmholtz Centre for Infection Research, Inhoffenstr. 7, 38124, Braunschweig, Germany
| | - Stefan Schmelz
- Department Structure and Function of Proteins, Helmholtz Centre for Infection Research, Inhoffenstr. 7, 38124, Braunschweig, Germany
| | - Susanne Zur Lage
- Department Structure and Function of Proteins, Helmholtz Centre for Infection Research, Inhoffenstr. 7, 38124, Braunschweig, Germany
| | - Sven-Kevin Hotop
- Department Chemical Biology, Helmholtz Centre for Infection Research, Inhoffenstr. 7, 38124, Braunschweig, Germany
| | - Steffi Stephen
- Department Chemical Biology, Helmholtz Centre for Infection Research, Inhoffenstr. 7, 38124, Braunschweig, Germany
| | - Dennis Lübken
- Institute of Organic Chemistry, Leibniz University Hannover, Schneiderberg 1B, 30167, Hannover, Germany
| | - Jonas Krüger
- Department Molecular Bacteriology, Helmholtz Centre for Infection Research, Inhoffenstr. 7, 38124, Braunschweig, Germany
| | - Nicolas Oswaldo Gomez
- Department Molecular Bacteriology, Helmholtz Centre for Infection Research, Inhoffenstr. 7, 38124, Braunschweig, Germany
| | - Marco van Ham
- Cellular Proteomics, Helmholtz Centre for Infection Research, Inhoffenstr. 7, 38124, Braunschweig, Germany
| | - Lothar Jänsch
- Cellular Proteomics, Helmholtz Centre for Infection Research, Inhoffenstr. 7, 38124, Braunschweig, Germany
| | - Markus Kalesse
- Institute of Organic Chemistry, Leibniz University Hannover, Schneiderberg 1B, 30167, Hannover, Germany
| | - Andreas Pich
- Institute for Toxicology, Core Facility Proteomics, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
| | - Mark Brönstrup
- Department Chemical Biology, Helmholtz Centre for Infection Research, Inhoffenstr. 7, 38124, Braunschweig, Germany
| | - Susanne Häussler
- Department Molecular Bacteriology, Helmholtz Centre for Infection Research, Inhoffenstr. 7, 38124, Braunschweig, Germany
| | - Wulf Blankenfeldt
- Department Structure and Function of Proteins, Helmholtz Centre for Infection Research, Inhoffenstr. 7, 38124, Braunschweig, Germany.
- Institute for Biochemistry, Biotechnology and Bioinformatics, Technische Universität Braunschweig, Spielmannstr. 7, 38106, Braunschweig, Germany.
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11
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Zhou K, Kammarchedu V, Butler D, Soltan Khamsi P, Ebrahimi A. Electrochemical Sensors Based on MoS x -Functionalized Laser-Induced Graphene for Real-Time Monitoring of Phenazines Produced by Pseudomonas aeruginosa. Adv Healthc Mater 2022; 11:e2200773. [PMID: 35853169 PMCID: PMC9547893 DOI: 10.1002/adhm.202200773] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 06/21/2022] [Indexed: 01/27/2023]
Abstract
Pseudomonas aeruginosa (P. aeruginosa) is an opportunistic pathogen causing infections in blood and implanted devices. Traditional identification methods take more than 24 h to produce results. Molecular biology methods expedite detection, but require an advanced skill set. To address these challenges, this work demonstrates functionalization of laser-induced graphene (LIG) for developing flexible electrochemical sensors for P. aeruginosa based on phenazines. Electrodeposition as a facile approach is used to functionalize LIG with molybdenum polysulfide (MoSx ). The sensor's limit of detection (LOD), sensitivity, and specificity are determined in broth, agar, and wound simulating medium (WSM). Control experiments with Escherichia coli, which does not produce phenazines, demonstrate specificity of sensors for P. aeruginosa. The LOD for pyocyanin (PYO) and phenazine-1-carboxylic acid (PCA) is 0.19 × 10-6 and 1.2 × 10-6 m, respectively. Furthermore, the highly stable sensors enable real-time monitoring of P. aeruginosa biofilms over several days. Comparing square wave voltammetry data over time shows time-dependent generation of phenazines. In particular, two configurations-"Normal" and "Flipped"-are studied, showing that the phenazines time dynamics vary depending on how cells interact with sensors. The reported results demonstrate the potential of the developed sensors for integration with wound dressings for early diagnosis of P. aeruginosa infection.
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Affiliation(s)
- Keren Zhou
- School of Electrical Engineering and Computer Science, The Pennsylvania State University, University Park, PA 16802, USA
- Materials Research Institute, The Pennsylvania State University, University Park, PA 16802, USA
| | - Vinay Kammarchedu
- School of Electrical Engineering and Computer Science, The Pennsylvania State University, University Park, PA 16802, USA
- Materials Research Institute, The Pennsylvania State University, University Park, PA 16802, USA
| | - Derrick Butler
- School of Electrical Engineering and Computer Science, The Pennsylvania State University, University Park, PA 16802, USA
- Materials Research Institute, The Pennsylvania State University, University Park, PA 16802, USA
| | - Pouya Soltan Khamsi
- School of Electrical Engineering and Computer Science, The Pennsylvania State University, University Park, PA 16802, USA
- Materials Research Institute, The Pennsylvania State University, University Park, PA 16802, USA
| | - Aida Ebrahimi
- School of Electrical Engineering and Computer Science, The Pennsylvania State University, University Park, PA 16802, USA
- Materials Research Institute, The Pennsylvania State University, University Park, PA 16802, USA
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA 16802, USA
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12
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Letizia M, Mellini M, Fortuna A, Visca P, Imperi F, Leoni L, Rampioni G. PqsE Expands and Differentially Modulates the RhlR Quorum Sensing Regulon in Pseudomonas aeruginosa. Microbiol Spectr 2022; 10:e0096122. [PMID: 35604161 PMCID: PMC9241726 DOI: 10.1128/spectrum.00961-22] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 05/02/2022] [Indexed: 12/22/2022] Open
Abstract
In the opportunistic pathogen Pseudomonas aeruginosa, many virulence traits are finely regulated by quorum sensing (QS), an intercellular communication system that allows the cells of a population to coordinate gene expression in response to cell density. The key aspects underlying the functionality of the complex regulatory network governing QS in P. aeruginosa are still poorly understood, including the interplay between the effector protein PqsE and the transcriptional regulator RhlR in controlling the QS regulon. Different studies have focused on the characterization of PqsE- and RhlR-controlled genes in genetic backgrounds in which RhlR activity can be modulated by PqsE and pqsE expression is controlled by RhlR, thus hampering identification of the distinct regulons controlled by PqsE and RhlR. In this study, a P. aeruginosa PAO1 mutant strain with deletion of multiple QS elements and inducible expression of pqsE and/or rhlR was generated and validated. Transcriptomic analyses performed on this genetic background allowed us to unambiguously define the regulons controlled by PqsE and RhlR when produced alone or in combination. Transcriptomic data were validated via reverse transcription-quantitative PCR (RT-qPCR) and transcriptional fusions. Overall, our results showed that PqsE has a negligible effect on the P. aeruginosa transcriptome in the absence of RhlR, and that multiple RhlR subregulons exist with distinct dependency on PqsE. Overall, this study contributes to untangling the regulatory link between the pqs and rhl QS systems mediated by PqsE and RhlR and clarifying the impact of these QS elements on the P. aeruginosa transcriptome. IMPORTANCE The ability of Pseudomonas aeruginosa to cause difficult-to-treat infections relies on its capacity to fine-tune the expression of multiple virulence traits via the las, rhl, and pqs QS systems. Both the pqs effector protein PqsE and the rhl transcriptional regulator RhlR are required for full production of key virulence factors in vitro and pathogenicity in vivo. While it is known that PqsE can stimulate the ability of RhlR to control some virulence factors, no data are available to allow clear discrimination of the PqsE and RhlR regulons. The data produced in this study demonstrate that PqsE mainly impacts the P. aeruginosa transcriptome via an RhlR-dependent pathway and splits the RhlR regulon into PqsE-dependent and PqsE-independent subregulons. Besides contributing to untangling of the complex QS network of P. aeruginosa, our data confirm that both PqsE and RhlR are suitable targets for the development of antivirulence drugs.
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Affiliation(s)
| | - Marta Mellini
- Department of Science, Roma Tre University, Rome, Italy
| | | | - Paolo Visca
- Department of Science, Roma Tre University, Rome, Italy
- IRCCS Fondazione Santa Lucia, Rome, Italy
| | - Francesco Imperi
- Department of Science, Roma Tre University, Rome, Italy
- IRCCS Fondazione Santa Lucia, Rome, Italy
| | - Livia Leoni
- Department of Science, Roma Tre University, Rome, Italy
| | - Giordano Rampioni
- Department of Science, Roma Tre University, Rome, Italy
- IRCCS Fondazione Santa Lucia, Rome, Italy
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