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Kanno M, Shiota T, Ueno S, Takahara M, Haneda K, Tahara YO, Shintani M, Nakao R, Miyata M, Kimbara K, Futamata H, Tashiro Y. Identification of genes involved in enhanced membrane vesicle formation in Pseudomonas aeruginosa biofilms: surface sensing facilitates vesiculation. Front Microbiol 2023; 14:1252155. [PMID: 38107868 PMCID: PMC10722149 DOI: 10.3389/fmicb.2023.1252155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Accepted: 11/13/2023] [Indexed: 12/19/2023] Open
Abstract
Membrane vesicles (MVs) are small spherical structures (20-400 nm) produced by most bacteria and have important biological functions including toxin delivery, signal transfer, biofilm formation, and immunomodulation of the host. Although MV formation is enhanced in biofilms of a wide range of bacterial species, the underlying mechanisms are not fully understood. An opportunistic pathogen, Pseudomonas aeruginosa, causes chronic infections that can be difficult to treat due to biofilm formation. Since MVs are abundant in biofilms, can transport virulence factors to the host, and have inflammation-inducing functions, the mechanisms of enhanced MV formation in biofilms needs to be elucidated to effectively treat infections. In this study, we evaluated the characteristics of MVs in P. aeruginosa PAO1 biofilms, and identified factors that contribute to enhanced MV formation. Vesiculation was significantly enhanced in the static culture; MVs were connected to filamentous substances in the biofilm, and separation between the outer and inner membranes and curvature of the membrane were observed in biofilm cells. By screening a transposon mutant library (8,023 mutants) for alterations in MV formation in biofilms, 66 mutants were identified as low-vesiculation strains (2/3 decrease relative to wild type), whereas no mutant was obtained that produced more MVs (twofold increase). Some transposons were inserted into genes related to biofilm formation, including flagellar motility (flg, fli, and mot) and extracellular polysaccharide synthesis (psl). ΔpelAΔpslA, which does not synthesize the extracellular polysaccharides Pel and Psl, showed reduced MV production in biofilms but not in planktonic conditions, suggesting that enhanced vesiculation is closely related to the synthesis of biofilm matrices in P. aeruginosa. Additionally, we found that blebbing occurred during bacterial attachment. Our findings indicate that biofilm-related factors are closely involved in enhanced MV formation in biofilms and that surface sensing facilitates vesiculation. Furthermore, this work expands the understanding of the infection strategy in P. aeruginosa biofilms.
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Affiliation(s)
- Mizuki Kanno
- Graduate School of Science and Technology, Shizuoka University, Hamamatsu, Japan
- Department of Engineering, Graduate School of Integrated Science and Technology, Shizuoka University, Hamamatsu, Japan
| | - Takuya Shiota
- Department of Engineering, Graduate School of Integrated Science and Technology, Shizuoka University, Hamamatsu, Japan
| | - So Ueno
- Department of Engineering, Graduate School of Integrated Science and Technology, Shizuoka University, Hamamatsu, Japan
| | - Minato Takahara
- Department of Engineering, Graduate School of Integrated Science and Technology, Shizuoka University, Hamamatsu, Japan
| | - Keisuke Haneda
- Department of Applied Chemistry and Biochemical Engineering, Faculty of Engineering, Shizuoka University, Hamamatsu, Japan
| | - Yuhei O. Tahara
- Graduate School of Science, Osaka Metropolitan University, Osaka, Japan
| | - Masaki Shintani
- Graduate School of Science and Technology, Shizuoka University, Hamamatsu, Japan
- Department of Engineering, Graduate School of Integrated Science and Technology, Shizuoka University, Hamamatsu, Japan
- Department of Applied Chemistry and Biochemical Engineering, Faculty of Engineering, Shizuoka University, Hamamatsu, Japan
- Research Institute of Green Science and Technology, Shizuoka University, Shizuoka, Japan
- Japan Collection of Microorganisms, RIKEN BioResource Research Center, Tsukuba, Japan
| | - Ryoma Nakao
- Department of Bacteriology, National Institute of Infectious Diseases, Shinjuku, Tokyo, Japan
| | - Makoto Miyata
- Graduate School of Science, Osaka Metropolitan University, Osaka, Japan
| | - Kazuhide Kimbara
- Graduate School of Science and Technology, Shizuoka University, Hamamatsu, Japan
- Department of Engineering, Graduate School of Integrated Science and Technology, Shizuoka University, Hamamatsu, Japan
- Department of Applied Chemistry and Biochemical Engineering, Faculty of Engineering, Shizuoka University, Hamamatsu, Japan
| | - Hiroyuki Futamata
- Graduate School of Science and Technology, Shizuoka University, Hamamatsu, Japan
- Department of Engineering, Graduate School of Integrated Science and Technology, Shizuoka University, Hamamatsu, Japan
- Department of Applied Chemistry and Biochemical Engineering, Faculty of Engineering, Shizuoka University, Hamamatsu, Japan
- Research Institute of Green Science and Technology, Shizuoka University, Shizuoka, Japan
| | - Yosuke Tashiro
- Graduate School of Science and Technology, Shizuoka University, Hamamatsu, Japan
- Department of Engineering, Graduate School of Integrated Science and Technology, Shizuoka University, Hamamatsu, Japan
- Department of Applied Chemistry and Biochemical Engineering, Faculty of Engineering, Shizuoka University, Hamamatsu, Japan
- JST PRESTO, Kawaguchi, Japan
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Kalia M, Amari D, Davies DG, Sauer K. cis-DA-dependent dispersion by Pseudomonas aeruginosa biofilm and identification of cis-DA-sensory protein DspS. mBio 2023; 14:e0257023. [PMID: 38014955 PMCID: PMC10746223 DOI: 10.1128/mbio.02570-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 10/11/2023] [Indexed: 11/29/2023] Open
Abstract
IMPORTANCE Dispersion is an essential stage of the biofilm life cycle resulting in the release of bacteria from a biofilm into the surrounding environment. Dispersion contributes to bacterial survival by relieving overcrowding within a biofilm and allowing dissemination of cells into new habitats for colonization. Thus, dispersion can contribute to biofilm survival as well as disease progression and transmission. Cells dispersed from a biofilm rapidly lose their recalcitrant antimicrobial-tolerant biofilm phenotype and transition to a state that is susceptible to antibiotics. However, much of what is known about this biofilm developmental stage has been inferred from exogenously induced dispersion. Our findings provide the first evidence that native dispersion is coincident with reduced cyclic dimeric guanosine monophosphate levels, while also relying on at least some of the same factors that are central to the environmentally induced dispersion response, namely, BdlA, DipA, RbdA, and AmrZ. Additionally, we demonstrate for the first time that cis-DA signaling to induce dispersion is attributed to the two-component sensor/response regulator DspS, a homolog of the DSF sensor RpfC. Our findings also provide a path toward manipulating the native dispersion response as a novel and highly promising therapeutic intervention.
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Affiliation(s)
- Manmohit Kalia
- Department of Biological Sciences, Binghamton University, Binghamton, New York, USA
- Binghamton Biofilm Research Center, Binghamton University, Binghamton, New York, USA
| | - Diana Amari
- Department of Biological Sciences, Binghamton University, Binghamton, New York, USA
- Binghamton Biofilm Research Center, Binghamton University, Binghamton, New York, USA
| | - David G. Davies
- Department of Biological Sciences, Binghamton University, Binghamton, New York, USA
- Binghamton Biofilm Research Center, Binghamton University, Binghamton, New York, USA
| | - Karin Sauer
- Department of Biological Sciences, Binghamton University, Binghamton, New York, USA
- Binghamton Biofilm Research Center, Binghamton University, Binghamton, New York, USA
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3
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Song W, Ryu J, Jung J, Yu Y, Choi S, Kweon J. Dispersive biofilm from membrane bioreactor strains: effects of diffusible signal factor addition and characterization by dispersion index. Front Microbiol 2023; 14:1211761. [PMID: 37560518 PMCID: PMC10409479 DOI: 10.3389/fmicb.2023.1211761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 07/11/2023] [Indexed: 08/11/2023] Open
Abstract
INTRODUCTION Biofilm occurs ubiquitously in water system. Excessive biofilm formation deteriorates severely system performance in several water and wastewater treatment processes. Quorum sensing systems were controlled in this study with a signal compound cis-2-Decenoic acid (CDA) to regulate various functions of microbial communities, including motility, enzyme production, and extracellular polymeric substance (EPS) production in biofilm. METHODS The addition of CDA to six strains extracted from membrane bioreactor sludge and the Pseudomonas aeruginosa PAO1 strain was examined for modulating biofilm development by regulating DSF expression. RESULTS AND DISCUSSION As the CDA doses increased, optical density of the biofilm dispersion assay increased, and the decrease in EPS of the biofilm was obvious on membrane surfaces. The three-dimensional visual images and quantitative analyses of biofilm formation with CDA proved thinner, less massive, and more dispersive than those without; to evaluate its dispersive intensity, a dispersion index was proposed. This could compare the dispersive effects of CDA dosing to other biofilms or efficiencies of biofouling control practices such as backwashing or new cleaning methods.
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Affiliation(s)
- Wonjung Song
- The Academy of Applied Science and Technology, Konkuk University, Seoul, Republic of Korea
| | - Junhee Ryu
- Department of Civil and Environmental Engineering, Konkuk University, Seoul, Republic of Korea
| | - Jaehyun Jung
- HANSU Technical Service Ltd, Sungnam-si, Gyeonggi-do, Republic of Korea
| | - Youngjae Yu
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, AZ, United States
| | - Suyoung Choi
- The Academy of Applied Science and Technology, Konkuk University, Seoul, Republic of Korea
| | - Jihyang Kweon
- Department of Environmental Engineering Konkuk University, Seoul, Republic of Korea
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Cao P, Fleming D, Moustafa DA, Dolan SK, Szymanik KH, Redman WK, Ramos A, Diggle FL, Sullivan CS, Goldberg JB, Rumbaugh KP, Whiteley M. A Pseudomonas aeruginosa small RNA regulates chronic and acute infection. Nature 2023; 618:358-364. [PMID: 37225987 PMCID: PMC10247376 DOI: 10.1038/s41586-023-06111-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 04/21/2023] [Indexed: 05/26/2023]
Abstract
The ability to switch between different lifestyles allows bacterial pathogens to thrive in diverse ecological niches1,2. However, a molecular understanding of their lifestyle changes within the human host is lacking. Here, by directly examining bacterial gene expression in human-derived samples, we discover a gene that orchestrates the transition between chronic and acute infection in the opportunistic pathogen Pseudomonas aeruginosa. The expression level of this gene, here named sicX, is the highest of the P. aeruginosa genes expressed in human chronic wound and cystic fibrosis infections, but it is expressed at extremely low levels during standard laboratory growth. We show that sicX encodes a small RNA that is strongly induced by low-oxygen conditions and post-transcriptionally regulates anaerobic ubiquinone biosynthesis. Deletion of sicX causes P. aeruginosa to switch from a chronic to an acute lifestyle in multiple mammalian models of infection. Notably, sicX is also a biomarker for this chronic-to-acute transition, as it is the most downregulated gene when a chronic infection is dispersed to cause acute septicaemia. This work solves a decades-old question regarding the molecular basis underlying the chronic-to-acute switch in P. aeruginosa and suggests oxygen as a primary environmental driver of acute lethality.
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Affiliation(s)
- Pengbo Cao
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
- Emory-Children's Cystic Fibrosis Center, Atlanta, GA, USA
- Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, GA, USA
| | - Derek Fleming
- Department of Surgery, Texas Tech University Health Sciences Center, Lubbock, TX, USA
- Department of Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, TX, USA
- Burn Center of Research Excellence, Texas Tech University Health Sciences Center, Lubbock, TX, USA
- Division of Clinical Microbiology, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
| | - Dina A Moustafa
- Emory-Children's Cystic Fibrosis Center, Atlanta, GA, USA
- Department of Pediatrics, Division of Pulmonary, Asthma, Cystic Fibrosis, and Sleep, Emory University School of Medicine, Atlanta, GA, USA
| | - Stephen K Dolan
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
- Emory-Children's Cystic Fibrosis Center, Atlanta, GA, USA
- Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, GA, USA
| | - Kayla H Szymanik
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA
| | - Whitni K Redman
- Department of Surgery, Texas Tech University Health Sciences Center, Lubbock, TX, USA
- Department of Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, TX, USA
- Burn Center of Research Excellence, Texas Tech University Health Sciences Center, Lubbock, TX, USA
- Department of Biological Sciences, Binghamton University, Binghamton, NY, USA
| | - Anayancy Ramos
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
- Emory-Children's Cystic Fibrosis Center, Atlanta, GA, USA
- Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, GA, USA
| | - Frances L Diggle
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
- Emory-Children's Cystic Fibrosis Center, Atlanta, GA, USA
- Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, GA, USA
| | | | - Joanna B Goldberg
- Emory-Children's Cystic Fibrosis Center, Atlanta, GA, USA
- Department of Pediatrics, Division of Pulmonary, Asthma, Cystic Fibrosis, and Sleep, Emory University School of Medicine, Atlanta, GA, USA
| | - Kendra P Rumbaugh
- Department of Surgery, Texas Tech University Health Sciences Center, Lubbock, TX, USA
- Department of Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, TX, USA
- Burn Center of Research Excellence, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Marvin Whiteley
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA.
- Emory-Children's Cystic Fibrosis Center, Atlanta, GA, USA.
- Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, GA, USA.
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Schulze AS, Kleinau G, Krakowsky R, Rochmann D, Das R, Worth CL, Krumbholz P, Scheerer P, Stäubert C. Evolutionary analyses reveal immune cell receptor GPR84 as a conserved receptor for bacteria-derived molecules. iScience 2022; 25:105087. [PMID: 36164652 PMCID: PMC9508565 DOI: 10.1016/j.isci.2022.105087] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 07/26/2022] [Accepted: 08/31/2022] [Indexed: 10/31/2022] Open
Abstract
The G protein-coupled receptor 84 (GPR84) is found in immune cells and its expression is increased under inflammatory conditions. Activation of GPR84 by medium-chain fatty acids results in pro-inflammatory responses. Here, we screened available vertebrate genome data and found that GPR84 is present in vertebrates for more than 500 million years but absent in birds and a pseudogene in bats. Cloning and functional characterization of several mammalian GPR84 orthologs in combination with evolutionary and model-based structural analyses revealed evidence for positive selection of bear GPR84 orthologs. Naturally occurring human GPR84 variants are most frequent in Asian populations causing a loss of function. Further, we identified cis- and trans-2-decenoic acid, both known to mediate bacterial communication, as evolutionary highly conserved ligands. Our integrated set of approaches contributes to a comprehensive understanding of GPR84 in terms of evolutionary and structural aspects, highlighting GPR84 as a conserved immune cell receptor for bacteria-derived molecules.
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Affiliation(s)
- Amadeus Samuel Schulze
- Rudolf Schönheimer Institute of Biochemistry, Faculty of Medicine, Leipzig University, Johannisallee 30, 04103 Leipzig, Germany
| | - Gunnar Kleinau
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Medical Physics and Biophysics, Group Protein X-ray Crystallography and Signal Transduction, Charitéplatz 1, 10117 Berlin, Germany
| | - Rosanna Krakowsky
- Rudolf Schönheimer Institute of Biochemistry, Faculty of Medicine, Leipzig University, Johannisallee 30, 04103 Leipzig, Germany
| | - David Rochmann
- Rudolf Schönheimer Institute of Biochemistry, Faculty of Medicine, Leipzig University, Johannisallee 30, 04103 Leipzig, Germany
| | - Ranajit Das
- Yenepoya Research Centre, Yenepoya University, Mangalore, Karnataka, India
| | - Catherine L Worth
- Independent Data Lab UG, Frauenmantelanger 31, 80937 Munich, Germany
| | - Petra Krumbholz
- Rudolf Schönheimer Institute of Biochemistry, Faculty of Medicine, Leipzig University, Johannisallee 30, 04103 Leipzig, Germany
| | - Patrick Scheerer
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Medical Physics and Biophysics, Group Protein X-ray Crystallography and Signal Transduction, Charitéplatz 1, 10117 Berlin, Germany
| | - Claudia Stäubert
- Rudolf Schönheimer Institute of Biochemistry, Faculty of Medicine, Leipzig University, Johannisallee 30, 04103 Leipzig, Germany
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6
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Reed CJ, Hutinet G, de Crécy-Lagard V. Comparative Genomic Analysis of the DUF34 Protein Family Suggests Role as a Metal Ion Chaperone or Insertase. Biomolecules 2021; 11:1282. [PMID: 34572495 PMCID: PMC8469502 DOI: 10.3390/biom11091282] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 08/20/2021] [Accepted: 08/24/2021] [Indexed: 12/12/2022] Open
Abstract
Members of the DUF34 (domain of unknown function 34) family, also known as the NIF3 protein superfamily, are ubiquitous across superkingdoms. Proteins of this family have been widely annotated as "GTP cyclohydrolase I type 2" through electronic propagation based on one study. Here, the annotation status of this protein family was examined through a comprehensive literature review and integrative bioinformatic analyses that revealed varied pleiotropic associations and phenotypes. This analysis combined with functional complementation studies strongly challenges the current annotation and suggests that DUF34 family members may serve as metal ion insertases, chaperones, or metallocofactor maturases. This general molecular function could explain how DUF34 subgroups participate in highly diversified pathways such as cell differentiation, metal ion homeostasis, pathogen virulence, redox, and universal stress responses.
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Affiliation(s)
- Colbie J. Reed
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL 32611, USA; (C.J.R.); (G.H.)
| | - Geoffrey Hutinet
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL 32611, USA; (C.J.R.); (G.H.)
| | - Valérie de Crécy-Lagard
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL 32611, USA; (C.J.R.); (G.H.)
- Genetics Institute, University of Florida, Gainesville, FL 32611, USA
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Harrison ZL, Awais R, Harris M, Raji B, Hoffman BC, Baker DL, Jennings JA. 2-Heptylcyclopropane-1-Carboxylic Acid Disperses and Inhibits Bacterial Biofilms. Front Microbiol 2021; 12:645180. [PMID: 34177826 PMCID: PMC8221421 DOI: 10.3389/fmicb.2021.645180] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 04/29/2021] [Indexed: 12/23/2022] Open
Abstract
Fatty-acid signaling molecules can inhibit biofilm formation, signal dispersal events, and revert dormant cells within biofilms to a metabolically active state. We synthesized 2-heptylcyclopropane-1-carboxylic acid (2CP), an analog of cis-2-decenoic acid (C2DA), which contains a cyclopropanated bond that may lock the signaling factor in an active state and prevent isomerization to its least active trans-configuration (T2DA). 2CP was compared to C2DA and T2DA for ability to disperse biofilms formed by Staphylococcus aureus and Pseudomonas aeruginosa. 2CP at 125 μg/ml dispersed approximately 100% of S. aureus cells compared to 25% for C2DA; both 2CP and C2DA had significantly less S. aureus biofilm remaining compared to T2DA, which achieved no significant dispersal. 2CP at 125 μg/ml dispersed approximately 60% of P. aeruginosa biofilms, whereas C2DA and T2DA at the same concentration dispersed 40%. When combined with antibiotics tobramycin, tetracycline, or levofloxacin, 2CP decreased the minimum concentration required for biofilm inhibition and eradication, demonstrating synergistic and additive responses for certain combinations. Furthermore, 2CP supported fibroblast viability above 80% for concentrations below 1 mg/ml. This study demonstrates that 2CP shows similar or improved efficacy in biofilm dispersion, inhibition, and eradication compared to C2DA and T2DA and thus may be promising for use in preventing infection for healthcare applications.
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Affiliation(s)
- Zoe L Harrison
- Department of Biomedical Engineering, University of Memphis, Memphis, TN, United States
| | - Rukhsana Awais
- Department of Biomedical Engineering, University of Memphis, Memphis, TN, United States
| | - Michael Harris
- Department of Biomedical Engineering, University of Memphis, Memphis, TN, United States
| | - Babatunde Raji
- Department of Chemistry, University of Memphis, Memphis, TN, United States
| | - Brian C Hoffman
- Department of Chemistry, University of Memphis, Memphis, TN, United States
| | - Daniel L Baker
- Department of Chemistry, University of Memphis, Memphis, TN, United States
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Juárez-Rodríguez MM, Cortes-López H, García-Contreras R, González-Pedrajo B, Díaz-Guerrero M, Martínez-Vázquez M, Rivera-Chávez JA, Soto-Hernández RM, Castillo-Juárez I. Tetradecanoic Acids With Anti-Virulence Properties Increase the Pathogenicity of Pseudomonas aeruginosa in a Murine Cutaneous Infection Model. Front Cell Infect Microbiol 2021; 10:597517. [PMID: 33585272 PMCID: PMC7876447 DOI: 10.3389/fcimb.2020.597517] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 12/08/2020] [Indexed: 12/25/2022] Open
Abstract
Blocking virulence is a promising alternative to counteract Pseudomonas aeruginosa infections. In this regard, the phenomenon of cell-cell communication by quorum sensing (QS) is an important anti-virulence target. In this field, fatty acids (FA) have gained notoriety for their role as autoinducers, as well as anti-virulence molecules in vitro, like some saturated FA (SAFA). In this study, we analyzed the anti-virulence activity of SAFA with 12 to18 carbon atoms and compared their effect with the putative autoinducer cis-2-decenoic acid (CDA). The effect of SAFA on six QS-regulated virulence factors and on the secretion of the exoenzyme ExoU was evaluated. In addition, a murine cutaneous infection model was used to determine their influence on the establishment and damage caused by P. aeruginosa PA14. Dodecanoic (lauric, C12:0) and tetradecanoic (myristic, C14:0) acids (SAFA C12-14) reduced the production of pyocyanin by 35-58% at 40 and 1,000 µM, while CDA inhibited it 62% at a 3.1 µM concentration. Moreover, the SAFA C12-14 reduced swarming by 90% without affecting biofilm formation. In contrast, CDA reduced the biofilm by 57% at 3 µM but did not affect swarming. Furthermore, lauric and myristic acids abolished ExoU secretion at 100 and 50 µM respectively, while CDA reduced it by ≈ 92% at 100 µM. Remarkably, the coadministration of myristic acid (200 and 1,000 µM) with P. aeruginosa PA14 induced greater damage and reduced survival of the animals up to 50%, whereas CDA to 500 µM reduced the damage without affecting the viability of the PA14 strain. Hence, our results show that SAFA C12-14 and CDA have a role in regulation of P. aeruginosa virulence, although their inhibition/activation molecular mechanisms are different in complex environments such as in vivo systems.
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Affiliation(s)
| | - Humberto Cortes-López
- Laboratorio de Fitoquímica, Posgrado de Botánica, Colegio de Postgraduados, Texcoco, Mexico
| | - Rodolfo García-Contreras
- Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Bertha González-Pedrajo
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Miguel Díaz-Guerrero
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Mariano Martínez-Vázquez
- Departamento de Productos Naturales, Instituto de Química, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - José Alberto Rivera-Chávez
- Departamento de Productos Naturales, Instituto de Química, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | | | - Israel Castillo-Juárez
- Laboratorio de Fitoquímica, Posgrado de Botánica, Colegio de Postgraduados, Texcoco, Mexico
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Abstract
During chronic lung infections, Pseudomonas aeruginosa grows in highly antibiotic-tolerant communities called biofilms that are difficult for the host to clear. We have developed models for studying P. aeruginosa biofilm dispersal in environments that replicate key features of the airway. We found that mechanisms of biofilm dispersal in these models may employ alternative or additional signaling mechanisms, highlighting the importance of the growth environment in dispersal events. We have adapted the models to accommodate apical fluid flow, bacterial clinical isolates, antibiotics, and primary human airway epithelial cells, all of which are relevant to understanding bacterial behaviors in the context of human disease. We also examined dispersal agents in combination with commonly used antipseudomonal antibiotics and saw improved clearance when nitrite was combined with the antibiotic aztreonam. Pseudomonas aeruginosa grows in highly antibiotic-tolerant biofilms during chronic airway infections. Dispersal of bacteria from biofilms may restore antibiotic susceptibility or improve host clearance. We describe models to study biofilm dispersal in the nutritionally complex environment of the human airway. P. aeruginosa was cocultured in the apical surface of airway epithelial cells (AECs) in a perfusion chamber. Dispersal, triggered by sodium nitrite, a nitric oxide (NO) donor, was tracked by live cell microscopy. Next, a static model was developed in which biofilms were grown on polarized AECs without flow. We observed that NO-triggered biofilm dispersal was an energy-dependent process. From the existing literature, NO-mediated biofilm dispersal is regulated by DipA, NbdA, RbdA, and MucR. Interestingly, altered signaling pathways appear to be used in this model, as deletion of these genes failed to block NO-induced biofilm dispersal. Similar results were observed using biofilms grown in an abiotic model on glass with iron-supplemented cell culture medium. In cystic fibrosis, airway mucus contributes to the growth environment, and a wide range of bacterial phenotypes are observed; therefore, we tested biofilm dispersal in a panel of late cystic fibrosis clinical isolates cocultured in the mucus overlying primary human AECs. Finally, we examined dispersal in combination with the clinically used antibiotics ciprofloxacin, aztreonam and tobramycin. In summary, we have validated models to study biofilm dispersal in environments that recapitulate key features of the airway and identified combinations of currently used antibiotics that may enhance the therapeutic effect of biofilm dispersal. IMPORTANCE During chronic lung infections, Pseudomonas aeruginosa grows in highly antibiotic-tolerant communities called biofilms that are difficult for the host to clear. We have developed models for studying P. aeruginosa biofilm dispersal in environments that replicate key features of the airway. We found that mechanisms of biofilm dispersal in these models may employ alternative or additional signaling mechanisms, highlighting the importance of the growth environment in dispersal events. We have adapted the models to accommodate apical fluid flow, bacterial clinical isolates, antibiotics, and primary human airway epithelial cells, all of which are relevant to understanding bacterial behaviors in the context of human disease. We also examined dispersal agents in combination with commonly used antipseudomonal antibiotics and saw improved clearance when nitrite was combined with the antibiotic aztreonam.
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Liu L, Li T, Cheng XJ, Peng CT, Li CC, He LH, Ju SM, Wang NY, Ye TH, Lian M, Xiao QJ, Song YJ, Zhu YB, Yu LT, Wang ZL, Bao R. Structural and functional studies on Pseudomonas aeruginosa DspI: implications for its role in DSF biosynthesis. Sci Rep 2018; 8:3928. [PMID: 29500457 PMCID: PMC5834635 DOI: 10.1038/s41598-018-22300-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Accepted: 02/15/2018] [Indexed: 02/05/2023] Open
Abstract
DspI, a putative enoyl-coenzyme A (CoA) hydratase/isomerase, was proposed to be involved in the synthesis of cis-2-decenoic acid (CDA), a quorum sensing (QS) signal molecule in the pathogen Pseudomonas aeruginosa (P. aeruginosa). The present study provided a structural basis for the dehydration reaction mechanism of DspI during CDA synthesis. Structural analysis reveals that Glu126, Glu146, Cys127, Cys131 and Cys154 are important for its enzymatic function. Moreover, we show that the deletion of dspI results in a remarkable decreased in the pyoverdine production, flagella-dependent swarming motility, and biofilm dispersion as well as attenuated virulence in P. aeruginosa PA14. This study thus unravels the mechanism of DspI in diffusible signal factor (DSF) CDA biosynthesis, providing vital information for developing inhibitors that interfere with DSF associated pathogenicity in P. aeruginosa.
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Affiliation(s)
- Li Liu
- Center of Infectious Diseases, West China Hospital, Sichuan University, Chengdu, China
- Department of Dermatology, Southwest Medical University, affiliated hospital, Luzhou, China
| | - Tao Li
- Center of Infectious Diseases, West China Hospital, Sichuan University, Chengdu, China
| | - Xing-Jun Cheng
- Center of Infectious Diseases, West China Hospital, Sichuan University, Chengdu, China
| | - Cui-Ting Peng
- Center of Infectious Diseases, West China Hospital, Sichuan University, Chengdu, China
| | - Chang-Cheng Li
- Center of Infectious Diseases, West China Hospital, Sichuan University, Chengdu, China
| | - Li-Hui He
- Center of Infectious Diseases, West China Hospital, Sichuan University, Chengdu, China
| | - Si-Min Ju
- Center of Infectious Diseases, West China Hospital, Sichuan University, Chengdu, China
| | - Ning-Yu Wang
- School of Life Science and Engineering, Southwest Jiaotong University, Chengdu, China
| | - Ting-Hong Ye
- Center of Infectious Diseases, West China Hospital, Sichuan University, Chengdu, China
| | - Mao Lian
- Center of Infectious Diseases, West China Hospital, Sichuan University, Chengdu, China
| | - Qing-Jie Xiao
- Center of Infectious Diseases, West China Hospital, Sichuan University, Chengdu, China
| | - Ying-Jie Song
- Center of Infectious Diseases, West China Hospital, Sichuan University, Chengdu, China
| | - Yi-Bo Zhu
- Center of Infectious Diseases, West China Hospital, Sichuan University, Chengdu, China
| | - Luo-Ting Yu
- Center of Infectious Diseases, West China Hospital, Sichuan University, Chengdu, China.
| | - Zhen-Ling Wang
- Center of Infectious Diseases, West China Hospital, Sichuan University, Chengdu, China.
| | - Rui Bao
- Center of Infectious Diseases, West China Hospital, Sichuan University, Chengdu, China.
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11
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Gunn JS, Bakaletz LO, Wozniak DJ. What's on the Outside Matters: The Role of the Extracellular Polymeric Substance of Gram-negative Biofilms in Evading Host Immunity and as a Target for Therapeutic Intervention. J Biol Chem 2016; 291:12538-12546. [PMID: 27129225 DOI: 10.1074/jbc.r115.707547] [Citation(s) in RCA: 121] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Biofilms are organized multicellular communities encased in an extracellular polymeric substance (EPS). Biofilm-resident bacteria resist immunity and antimicrobials. The EPS provides structural stability and presents a barrier; however, a complete understanding of how EPS structure relates to biological function is lacking. This review focuses on the EPS of three Gram-negative pathogens: Pseudomonas aeruginosa, nontypeable Haemophilus influenzae, and Salmonella enterica serovar Typhi/Typhimurium. Although EPS proteins and polysaccharides are diverse, common constituents include extracellular DNA, DNABII (DNA binding and bending) proteins, pili, flagella, and outer membrane vesicles. The EPS biochemistry promotes recalcitrance and informs the design of therapies to reduce or eliminate biofilm burden.
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Affiliation(s)
- John S Gunn
- Department of Microbial Infection and Immunity, Ohio State University, Columbus, Ohio 43210; Center for Microbial Interface Biology, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio 43205
| | - Lauren O Bakaletz
- Department of Microbial Infection and Immunity, Ohio State University, Columbus, Ohio 43210; Center for Microbial Interface Biology, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio 43205; Departments of Pediatrics and Otolaryngology, The Research Institute at Nationwide Children's Hospital and Ohio State University, Columbus, Ohio 43210
| | - Daniel J Wozniak
- Department of Microbial Infection and Immunity, Ohio State University, Columbus, Ohio 43210; Center for Microbial Interface Biology, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio 43205; Department of Microbiology, Ohio State University, Columbus, Ohio 43210.
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Going beyond the Control of Quorum-Sensing to Combat Biofilm Infections. Antibiotics (Basel) 2016; 5:antibiotics5010003. [PMID: 27025518 PMCID: PMC4810405 DOI: 10.3390/antibiotics5010003] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Revised: 11/27/2015] [Accepted: 12/30/2015] [Indexed: 11/17/2022] Open
Abstract
Most bacteria attach to surfaces where they form a biofilm, cells embedded in a complex matrix of polymers. Cells in biofilms are much better protected against noxious agents than free-living cells. As a consequence it is very difficult to control pathogens with antibiotics in biofilm infections and novel targets are urgently needed. One approach aims at the communication between cells to form and to maintain a biofilm, a process called quorum-sensing. Water soluble small-sized molecules mediate this process and a number of antagonists of these compounds have been found. In this review natural compounds and synthetic drugs which do not interfere with the classical quorum-sensing compounds are discussed. For some of these compounds the targets are still not known, but others interfere with the formation of exopolysaccharides, virulence factors, or cell wall synthesis or they start an internal program of biofilm dispersal. Some of their targets are more conserved among pathogens than the receptors for quorum sensing autoinducers mediating quorum-sensing, enabling a broader application of the drug. The broad spectrum of mechanisms, the diversity of bioactive compounds, their activity against several targets, and the conservation of some targets among bacterial pathogens are promising aspects for several clinical applications of this type of biofilm-controlling compound in the future.
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Control of Biofilms with the Fatty Acid Signaling Molecule cis-2-Decenoic Acid. Pharmaceuticals (Basel) 2015; 8:816-35. [PMID: 26610524 PMCID: PMC4695811 DOI: 10.3390/ph8040816] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Revised: 11/11/2015] [Accepted: 11/18/2015] [Indexed: 12/26/2022] Open
Abstract
Biofilms are complex communities of microorganisms in organized structures attached to surfaces. Importantly, biofilms are a major cause of bacterial infections in humans, and remain one of the most significant challenges to modern medical practice. Unfortunately, conventional therapies have shown to be inadequate in the treatment of most chronic biofilm infections based on the extraordinary innate tolerance of biofilms to antibiotics. Antagonists of quorum sensing signaling molecules have been used as means to control biofilms. QS and other cell-cell communication molecules are able to revert biofilm tolerance, prevent biofilm formation and disrupt fully developed biofilms, albeit with restricted effectiveness. Recently however, it has been demonstrated that Pseudomonas aeruginosa produces a small messenger molecule cis-2-decenoic acid (cis-DA) that shows significant promise as an effective adjunctive to antimicrobial treatment of biofilms. This molecule is responsible for induction of the native biofilm dispersion response in a range of Gram-negative and Gram-positive bacteria and in yeast, and has been shown to reverse persistence, increase microbial metabolic activity and significantly enhance the cidal effects of conventional antimicrobial agents. In this manuscript, the use of cis-2-decenoic acid as a novel agent for biofilm control is discussed. Stimulating the biofilm dispersion response as a novel antimicrobial strategy holds significant promise for enhanced treatment of infections and in the prevention of biofilm formation.
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