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Hsieh YYP, Sun W, Young JM, Cheung R, Hogan DA, Dandekar AA, Malik HS. Widespread fungal-bacterial competition for magnesium lowers bacterial susceptibility to polymyxin antibiotics. PLoS Biol 2024; 22:e3002694. [PMID: 38900845 PMCID: PMC11218974 DOI: 10.1371/journal.pbio.3002694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2024] [Revised: 07/02/2024] [Accepted: 05/29/2024] [Indexed: 06/22/2024] Open
Abstract
Fungi and bacteria coexist in many polymicrobial communities, yet the molecular basis of their interactions remains poorly understood. Here, we show that the fungus Candida albicans sequesters essential magnesium ions from the bacterium Pseudomonas aeruginosa. To counteract fungal Mg2+ sequestration, P. aeruginosa expresses the Mg2+ transporter MgtA when Mg2+ levels are low. Thus, loss of MgtA specifically impairs P. aeruginosa in co-culture with C. albicans, but fitness can be restored by supplementing Mg2+. Using a panel of fungi and bacteria, we show that Mg2+ sequestration is a general mechanism of fungal antagonism against gram-negative bacteria. Mg2+ limitation enhances bacterial resistance to polymyxin antibiotics like colistin, which target gram-negative bacterial membranes. Indeed, experimental evolution reveals that P. aeruginosa evolves C. albicans-dependent colistin resistance via non-canonical means; antifungal treatment renders resistant bacteria colistin-sensitive. Our work suggests that fungal-bacterial competition could profoundly impact polymicrobial infection treatment with antibiotics of last resort.
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Affiliation(s)
- Yu-Ying Phoebe Hsieh
- Division of Basic Sciences, Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
| | - Wanting Sun
- Division of Basic Sciences, Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
| | - Janet M. Young
- Division of Basic Sciences, Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
| | - Robin Cheung
- Department of Microbiology, University of Washington, Seattle, Washington, United States of America
| | - Deborah A. Hogan
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
| | - Ajai A. Dandekar
- Department of Microbiology, University of Washington, Seattle, Washington, United States of America
- Department of Medicine, University of Washington, Seattle, Washington, United States of America
| | - Harmit S. Malik
- Division of Basic Sciences, Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
- Howard Hughes Medical Institute, Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
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2
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Chourashi R, Oglesby AG. Iron starvation increases the production of the Pseudomonas aeruginosa RsmY and RsmZ sRNAs in static conditions. J Bacteriol 2024; 206:e0027823. [PMID: 38624234 PMCID: PMC11112995 DOI: 10.1128/jb.00278-23] [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] [Received: 08/24/2023] [Accepted: 03/22/2024] [Indexed: 04/17/2024] Open
Abstract
Pseudomonas aeruginosa is an opportunistic Gram-negative pathogen that induces virulence gene expression in response to host-mediated iron starvation. Recently, our laboratory showed that some virulence factors are responsive to iron limitation in static but not shaking growth conditions. One of these is the HSI-2-type six secretion system (T6SS), which is also induced during chronic infection. Iron regulation of T6SS was partially impacted by the iron-responsive PrrF sRNA and completely dependent upon the Pseudomonas quinolone signal (PQS) biosynthetic gene pqsA. Here, we analyzed the impact of iron on the expression of two small regulatory RNAs (sRNAs), RsmY and RsmZ, that activate the expression of T6SS by sequestering the RsmA translation inhibitor. Our results demonstrate that iron starvation induces the expression of RsmY and RsmZ in static but not shaking cultures. We further show that this induction occurs through the rsmY and rsmZ promoters and is dependent upon PqsA. Disruption of either the pqsR gene also eliminated iron-dependent regulation of rsmY and rsmZ promoter activity. Taken together, our results show novel targets of iron regulation that are specific to static growth, highlighting the importance of studying regulatory mechanisms in static communities that may be more representative of growth during chronic infection.IMPORTANCEIron is a central component of various bacterial metabolic pathways making it an important host-acquired nutrient for pathogens to establish infection. Previous iron regulatory studies primarily relied on shaking bacterial cultures; while these ensure cultural homogeneity, they do not reflect growth conditions during infection. We recently showed that static growth of Pseudomonas aeruginosa promotes iron-dependent regulation of a type six secretion system (T6SS), a virulence factor that is induced during chronic infections. In the current study, we found that static growth also promotes iron-dependent regulation of the RsmY and RsmZ sRNAs, which are global regulators that affect T6SS during chronic P. aeruginosa lung infection. Hence, our work demonstrates the Rsm sRNAs as potential effectors of iron regulation during static growth that may also be relevant in chronic infection.
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Affiliation(s)
- Rhishita Chourashi
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland, USA
| | - Amanda G. Oglesby
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland, USA
- Department of Microbiology and Immunology, School of Medicine, University of Maryland, Baltimore, Maryland, USA
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3
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Huang J, Xu Z, Zhou T, Zhang LH, Xu Z. Suppression of Pseudomonas aeruginosa type III secretion system by a novel calcium-responsive signaling pathway. iScience 2024; 27:109690. [PMID: 38660402 PMCID: PMC11039405 DOI: 10.1016/j.isci.2024.109690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 01/31/2024] [Accepted: 04/05/2024] [Indexed: 04/26/2024] Open
Abstract
Expression of the type III secretion system (T3SS) in Pseudomonas aeruginosa is exquisitely controlled by diverse environmental or host-related signals such as calcium (Ca2+), however, the signal transduction pathways remain largely elusive. In this study, we reported that FleR, the response regulator of the two-component system FleS/FleR, inhibits T3SS gene expression and virulence of P. aeruginosa uncoupled from its cognate histidine kinase FleS. Interestingly, FleR was found to repress T3SS gene expression under Ca2+-rich conditions independently of its DNA-binding domain. FleR activates the elevation of intracellular c-di-GMP contents and FleQ serves as the c-di-GMP effector to repress T3SS gene expression through the Gac/Rsm pathway. Remarkably, we found that AmrZ, a member of the FleR regulon, inhibits T3SS gene expression by directly targeting the promoter of exsCEBA in an expression level-dependent manner. This study revealed an intricate regulatory network that connects P. aeruginosa T3SS gene expression to the Ca2+ signal.
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Affiliation(s)
- Jiahui Huang
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
| | - Zirui Xu
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
| | - Tian Zhou
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
| | - Lian-Hui Zhang
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
- Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou, China
| | - Zeling Xu
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
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4
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Walsh D, Bevan J, Harrison F. How Does Airway Surface Liquid Composition Vary in Different Pulmonary Diseases, and How Can We Use This Knowledge to Model Microbial Infections? Microorganisms 2024; 12:732. [PMID: 38674677 PMCID: PMC11052052 DOI: 10.3390/microorganisms12040732] [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: 03/11/2024] [Revised: 03/26/2024] [Accepted: 03/28/2024] [Indexed: 04/28/2024] Open
Abstract
Growth environment greatly alters many facets of pathogen physiology, including pathogenesis and antimicrobial tolerance. The importance of host-mimicking environments for attaining an accurate picture of pathogen behaviour is widely recognised. Whilst this recognition has translated into the extensive development of artificial cystic fibrosis (CF) sputum medium, attempts to mimic the growth environment in other respiratory disease states have been completely neglected. The composition of the airway surface liquid (ASL) in different pulmonary diseases is far less well characterised than CF sputum, making it very difficult for researchers to model these infection environments. In this review, we discuss the components of human ASL, how different lung pathologies affect ASL composition, and how different pathogens interact with these components. This will provide researchers interested in mimicking different respiratory environments with the information necessary to design a host-mimicking medium, allowing for better understanding of how to treat pathogens causing infection in these environments.
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Affiliation(s)
- Dean Walsh
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK (F.H.)
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5
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Neff SL, Doing G, Reiter T, Hampton TH, Greene CS, Hogan DA. Pseudomonas aeruginosa transcriptome analysis of metal restriction in ex vivo cystic fibrosis sputum. Microbiol Spectr 2024; 12:e0315723. [PMID: 38385740 PMCID: PMC10986534 DOI: 10.1128/spectrum.03157-23] [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] [Received: 08/24/2023] [Accepted: 01/22/2024] [Indexed: 02/23/2024] Open
Abstract
Chronic Pseudomonas aeruginosa lung infections are a feature of cystic fibrosis (CF) that many patients experience even with the advent of highly effective modulator therapies. Identifying factors that impact P. aeruginosa in the CF lung could yield novel strategies to eradicate infection or otherwise improve outcomes. To complement published P. aeruginosa studies using laboratory models or RNA isolated from sputum, we analyzed transcripts of strain PAO1 after incubation in sputum from different CF donors prior to RNA extraction. We compared PAO1 gene expression in this "spike-in" sputum model to that for P. aeruginosa grown in synthetic cystic fibrosis sputum medium to determine key genes, which are among the most differentially expressed or most highly expressed. Using the key genes, gene sets with correlated expression were determined using the gene expression analysis tool eADAGE. Gene sets were used to analyze the activity of specific pathways in P. aeruginosa grown in sputum from different individuals. Gene sets that we found to be more active in sputum showed similar activation in published data that included P. aeruginosa RNA isolated from sputum relative to corresponding in vitro reference cultures. In the ex vivo samples, P. aeruginosa had increased levels of genes related to zinc and iron acquisition which were suppressed by metal amendment of sputum. We also found a significant correlation between expression of the H1-type VI secretion system and CFTR corrector use by the sputum donor. An ex vivo sputum model or synthetic sputum medium formulation that imposes metal restriction may enhance future CF-related studies.IMPORTANCEIdentifying the gene expression programs used by Pseudomonas aeruginosa to colonize the lungs of people with cystic fibrosis (CF) will illuminate new therapeutic strategies. To capture these transcriptional programs, we cultured the common P. aeruginosa laboratory strain PAO1 in expectorated sputum from CF patient donors. Through bioinformatic analysis, we defined sets of genes that are more transcriptionally active in real CF sputum compared to a synthetic cystic fibrosis sputum medium. Many of the most differentially active gene sets contained genes related to metal acquisition, suggesting that these gene sets play an active role in scavenging for metals in the CF lung environment which may be inadequately represented in some models. Future studies of P. aeruginosa transcript abundance in CF may benefit from the use of an expectorated sputum model or media supplemented with factors that induce metal restriction.
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Affiliation(s)
- Samuel L. Neff
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Georgia Doing
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Taylor Reiter
- Department of Biomedical Informatics, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Thomas H. Hampton
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Casey S. Greene
- Department of Biomedical Informatics, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Deborah A. Hogan
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
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6
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Morales LD, Av-Gay Y, Murphy MEP. Acidic pH modulates Burkholderia cenocepacia antimicrobial susceptibility in the cystic fibrosis nutritional environment. Microbiol Spectr 2023; 11:e0273123. [PMID: 37966209 PMCID: PMC10714822 DOI: 10.1128/spectrum.02731-23] [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] [Received: 07/17/2023] [Accepted: 10/06/2023] [Indexed: 11/16/2023] Open
Abstract
IMPORTANCE Burkholderia cenocepacia causes severe infections in cystic fibrosis (CF) patients. CF patients are prone to reoccurring infections due to the accumulation of mucus in their lungs, where bacteria can adhere and grow. Some of the antibiotics that inhibit B. cenocepacia in the laboratory are not effective for CF patients. A major contributor to poor clinical outcomes is that antibiotic testing in laboratories occurs under conditions that are different from those of sputum. CF sputum may be acidic and have increased concentrations of iron and zinc. Here, we used a medium that mimics CF sputum and found that acidic pH decreased the activity of many of the antibiotics used against B. cenocepacia. In addition, we assessed susceptibility to more than 500 antibiotics and found four active compounds against B. cenocepacia. Our findings give a better understanding of the lack of a relationship between susceptibility testing and the clinical outcome when treating B. cenocepacia infections.
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Affiliation(s)
- L. Daniela Morales
- Department of Microbiology and Immunology, Life Sciences Institute, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Yossef Av-Gay
- Department of Microbiology and Immunology, Life Sciences Institute, The University of British Columbia, Vancouver, British Columbia, Canada
- Department of Medicine, Division of Infectious Diseases, Life Sciences Institute, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Michael E. P. Murphy
- Department of Microbiology and Immunology, Life Sciences Institute, The University of British Columbia, Vancouver, British Columbia, Canada
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7
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Kolodkin-Gal I, Parsek MR, Patrauchan MA. The roles of calcium signaling and calcium deposition in microbial multicellularity. Trends Microbiol 2023; 31:1225-1237. [PMID: 37429751 PMCID: PMC10772221 DOI: 10.1016/j.tim.2023.06.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 06/07/2023] [Accepted: 06/12/2023] [Indexed: 07/12/2023]
Abstract
Calcium signaling is an essential mediator of signal-controlling gene expression in most developmental systems. In addition, calcium has established extracellular functions as a structural component of biogenic minerals found in complex tissues. In bacteria, the formation of calcium carbonate structures is associated with complex colony morphology. Genes promoting the formation of biogenic minerals are essential for proper biofilm development and protection against antimicrobial solutes and toxins. Here we review recent findings on the role of calcium and calcium signaling as emerging regulators of biofilm formation in beneficial bacteria, as well as essential mediators of biofilm formation and virulence in human pathogens. The presented analysis concludes that the new understanding of calcium signaling may help to improve the performance of beneficial strains for sustainable agriculture, microbiome manipulation, and sustainable construction. Unraveling the roles of calcium may also promote the development of novel therapies against biofilm infections that target calcium uptake, calcium sensors, and calcium carbonate deposition.
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Affiliation(s)
- Ilana Kolodkin-Gal
- Department of Plant Pathology and Microbiology, Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel.
| | - Matthew R Parsek
- Department of Microbiology, University of Washington, Seattle, WA, USA.
| | - Marianna A Patrauchan
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, USA.
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8
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Hills OJ, Noble IO, Heyam A, Scott AJ, Smith J, Chappell HF. Atomistic modelling and NMR studies reveal that gallium can target the ferric PQS uptake system in P. aeruginosa biofilms. MICROBIOLOGY (READING, ENGLAND) 2023; 169:001422. [PMID: 38117289 PMCID: PMC10765035 DOI: 10.1099/mic.0.001422] [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: 08/08/2022] [Accepted: 12/11/2023] [Indexed: 12/21/2023]
Abstract
Intravenous gallium nitrate therapy is a novel therapeutic strategy deployed to combat chronic Pseudomonas aeruginosa biofilm infections in the lungs of cystic fibrosis (CF) patients by interfering with iron (Fe3+) uptake. The therapy is a source of Ga3+, which competes with Fe3+ for siderophore binding, subsequently disrupting iron metabolism and inhibiting biofilm proliferation in vivo. It was recently demonstrated that the Pseudomonas quinolone signal (PQS) can chelate Fe3+ to assist in bacterial iron uptake. However, it is unknown whether exogenous gallium also targets [Fe(PQS)3] uptake, which, in turn, would extend the mechanism of gallium therapy beyond siderophore competition, potentially supporting use of the therapy against P. aeruginosa mutants deficient in siderophore uptake proteins. To that end, the thermodynamic feasibility of iron-for-gallium cation exchange into [Fe(PQS)3] was evaluated using quantum chemical density functional theory (DFT) modelling and verified experimentally using 1H nuclear magnetic resonance (NMR). We demonstrate here that Ga3+ can strongly bind to three PQS molecules and, furthermore, displace and substitute Fe3+ from the native chelate pocket within PQS complexes, through a Trojan horse mechanism, retaining the key structural features present within the native ferric complex. As such, [Fe(PQS)3] complexes, in addition to ferric-siderophore complexes, represent another target for gallium therapy.
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Affiliation(s)
- Oliver J. Hills
- School of Food Science and Nutrition, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK
| | - Isaac O.K. Noble
- School of Food Science and Nutrition, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK
| | - Alex Heyam
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK
| | - Andrew J. Scott
- School of Chemical and Process Engineering, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK
| | - James Smith
- School of Food Science and Nutrition, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK
| | - Helen F. Chappell
- School of Food Science and Nutrition, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK
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9
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Potok P, Kola A, Valensin D, Capdevila M, Potocki S. Copper Forms a PPII Helix-Like Structure with the Catalytic Domains of Bacterial Zinc Metalloproteases. Inorg Chem 2023; 62:18425-18439. [PMID: 37909295 PMCID: PMC10647932 DOI: 10.1021/acs.inorgchem.3c02391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 10/11/2023] [Accepted: 10/11/2023] [Indexed: 11/03/2023]
Abstract
The rapid spread of antibiotic-resistant bacteria continuously raises concerns about the future ineffectiveness of current antimicrobial treatments against infectious diseases. To address this problem, new therapeutic strategies and antimicrobial drugs with unique modes of action are urgently needed. Inhibition of metalloproteases, bacterial virulence factors, is a promising target for the development of antibacterial treatments. In this study, the interaction among Zn(II), Cu(II), and the metal-binding domains of two metalloproteases, AprA (Pseudomonas aureginosa) and CpaA (Acinetobacter baumanii), was investigated. The objective was to determine the coordination sphere of Zn(II) with a peptide model of two zinc-dependent metalloproteases. Additionally, the study explored the formation of Cu(II) complexes with the domains, as Cu(II) has been shown to inhibit metalloproteases. The third aim was to understand the role of nonbinding amino acids in stabilizing the metal complexes formed by these proteases. This work identified specific coordination patterns (HExxHxxxxxH) for both Zn(II) and Cu(II) complexes, with AprA and CpaA exhibiting a higher affinity for Cu(II) compared to Zn(II). The study also found that the CpaA domain has greater stability for both Zn(II) and Cu(II) complexes compared to AprA. The nonbinding amino acids of CpaA surrounding the metal ion contribute to the increased thermodynamic stability of the metal-peptide complex through various intramolecular interactions. These interactions can also influence the secondary structures of the peptides. The presence of certain amino acids, such as tyrosine, arginine, and glutamic acid, and their interactions contribute to the stability and, only in the case of Cu(II) complexes, the formation of a rare protein structure called a left-handed polyproline II helix (PPII), which is known to play a role in the stability and function of various proteins. These findings provide valuable insights into the coordination chemistry of bacterial metalloproteases and expand our understanding of potential mechanisms for inhibiting these enzymes.
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Affiliation(s)
- Paulina Potok
- Faculty
of Chemistry, University of Wroclaw, 50-383 Wroclaw, Poland
| | - Arian Kola
- Department
of Biotechnology, Chemistry and Pharmacy, University of Siena, Via Aldo Moro 2, 53100 Siena, Italy
| | - Daniela Valensin
- Department
of Biotechnology, Chemistry and Pharmacy, University of Siena, Via Aldo Moro 2, 53100 Siena, Italy
| | - Merce Capdevila
- Departament
de Química, Universitat Autònoma
de Barcelona, 08193 Cerdanyola del Vallès, Spain
| | - Sławomir Potocki
- Faculty
of Chemistry, University of Wroclaw, 50-383 Wroclaw, Poland
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10
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Neff SL, Doing G, Reiter T, Hampton TH, Greene CS, Hogan DA. Analysis of Pseudomonas aeruginosa transcription in an ex vivo cystic fibrosis sputum model identifies metal restriction as a gene expression stimulus. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.21.554169. [PMID: 37662412 PMCID: PMC10473638 DOI: 10.1101/2023.08.21.554169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
Chronic Pseudomonas aeruginosa lung infections are a distinctive feature of cystic fibrosis (CF) pathology, that challenge adults with CF even with the advent of highly effective modulator therapies. Characterizing P. aeruginosa transcription in the CF lung and identifying factors that drive gene expression could yield novel strategies to eradicate infection or otherwise improve outcomes. To complement published P. aeruginosa gene expression studies in laboratory culture models designed to model the CF lung environment, we employed an ex vivo sputum model in which laboratory strain PAO1 was incubated in sputum from different CF donors. As part of the analysis, we compared PAO1 gene expression in this "spike-in" sputum model to that for P. aeruginosa grown in artificial sputum medium (ASM). Analyses focused on genes that were differentially expressed between sputum and ASM and genes that were most highly expressed in sputum. We present a new approach that used sets of genes with correlated expression, identified by the gene expression analysis tool eADAGE, to analyze the differential activity of pathways in P. aeruginosa grown in CF sputum from different individuals. A key characteristic of P. aeruginosa grown in expectorated CF sputum was related to zinc and iron acquisition, but this signal varied by donor sputum. In addition, a significant correlation between P. aeruginosa expression of the H1-type VI secretion system and corrector use by the sputum donor was observed. These methods may be broadly useful in looking for variable signals across clinical samples.
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Affiliation(s)
- Samuel L. Neff
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA
| | - Georgia Doing
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA
| | - Taylor Reiter
- Department of Biomedical Informatics, University of Colorado School of Medicine, Aurora, CO, USA
| | - Thomas H. Hampton
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA
| | - Casey S. Greene
- Department of Biomedical Informatics, University of Colorado School of Medicine, Aurora, CO, USA
| | - Deborah A. Hogan
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA
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11
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Park S, Dingemans J, Sauer K. Manganese Acts as an Environmental Inhibitor of Pseudomonas aeruginosa Biofilm Development by Inducing Dispersion and Modulating c-di-GMP and Exopolysaccharide Production via RbdA. J Bacteriol 2023; 205:e0000323. [PMID: 37199658 PMCID: PMC10294637 DOI: 10.1128/jb.00003-23] [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] [Received: 01/03/2023] [Accepted: 04/27/2023] [Indexed: 05/19/2023] Open
Abstract
The opportunistic human pathogen Pseudomonas aeruginosa causes chronic infections that involve multicellular aggregates called biofilms. Biofilm formation is modulated by the host environment and the presence of cues and/or signals, likely affecting the pool of the bacterial second messenger cyclic diguanylate monophosphate (c-di-GMP). The manganese ion Mn2+ is a divalent metal cation that is essential for pathogenic bacterial survival and replication during the infection in a host organism. In this study, we investigated how Mn2+ alters P. aeruginosa biofilm formation via the regulation of c-di-GMP levels. Exposure to Mn2+ was found to temporally enhance attachment but impair subsequent biofilm development, apparent by reduced biofilm biomass accumulation and lack of microcolony formation due to the induction of dispersion. Moreover, exposure to Mn2+ coincided with reduced production of the exopolysaccharides Psl and Pel, decreased transcriptional abundance of pel and psl, and decreased levels of c-di-GMP. To determine whether the effect of Mn2+ was linked to the activation of phosphodiesterases (PDEs), we screened several PDE mutants for Mn2+-dependent phenotypes (attachment and polysaccharide production) as well as PDE activity. The screen revealed that the PDE RbdA is activated by Mn2+ and is responsible for Mn2+-dependent attachment, inhibition of Psl production, and dispersion. Taken together, our findings suggest Mn2+ is an environmental inhibitor of P. aeruginosa biofilm development that acts through the PDE RbdA to modulate c-di-GMP levels, thereby impeding polysaccharide production and biofilm formation but enhancing dispersion. IMPORTANCE While diverse environmental conditions such as the availability of metal ions have been shown to affect biofilm development, little is known about the mechanism. Here, we demonstrate that Mn2+ affects Pseudomonas aeruginosa biofilm development by stimulating phosphodiesterase RbdA activity to reduce the signaling molecule c-di-GMP levels, thereby hindering polysaccharide production and biofilm formation but enhancing dispersion. Our findings demonstrate that Mn2+ acts as an environmental inhibitor of P. aeruginosa biofilms, further suggesting manganese to be a promising new antibiofilm factor.
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Affiliation(s)
- Soyoung Park
- Department of Biological Sciences, Binghamton University, Binghamton, New York, USA
- Binghamton Biofilm Research Center, Binghamton University, Binghamton, New York, USA
| | - Jozef Dingemans
- 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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12
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Hills OJ, Poskrobko Z, Scott AJ, Smith J, Chappell HF. A DFT study of the gallium ion-binding capacity of mature Pseudomonas aeruginosa biofilm extracellular polysaccharide. PLoS One 2023; 18:e0287191. [PMID: 37315081 DOI: 10.1371/journal.pone.0287191] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 06/01/2023] [Indexed: 06/16/2023] Open
Abstract
Intravenous gallium therapy is a non-antibiotic approach to limit Pseudomonas aeruginosa biofilm proliferation, by outcompeting iron for siderophore binding. Gallium therapy represents a viable therapeutic strategy for cystic fibrosis (CF) patients harbouring mucoid P. aeruginosa biofilm lung infections. Siderophore deficient P. aeruginosa isolates still demonstrate a hindered biofilm proliferation when exposed to gallium but it is currently unknown whether exogenous gallium has any disruptive influence on the exopolysaccharide (EPS), the major mucoid P. aeruginosa CF lung biofilm matrix component. To that end, Density-Functional Theory (DFT) was deployed to assess whether gallium (Ga3+) could be substituted into the mature mucoid EPS scaffold in preference of calcium (Ca2+)-the native EPS cross-linking ion. Removal of the stable, bound native calcium ions offers a large enthalpic barrier to the substitution and the mature EPS fails to accommodate exogenous gallium. This suggests that gallium, perhaps, is utilising a novel, possibly unknown, ferric uptake system to gain entry to siderophore deficient cells.
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Affiliation(s)
- Oliver J Hills
- School of Food Science & Nutrition, University of Leeds, Woodhouse Lane, Leeds, United Kingdom
| | - Zuzanna Poskrobko
- School of Food Science & Nutrition, University of Leeds, Woodhouse Lane, Leeds, United Kingdom
| | - Andrew J Scott
- School of Chemical & Process Engineering, University of Leeds, Woodhouse Lane, Leeds, United Kingdom
| | - James Smith
- School of Food Science & Nutrition, University of Leeds, Woodhouse Lane, Leeds, United Kingdom
| | - Helen F Chappell
- School of Food Science & Nutrition, University of Leeds, Woodhouse Lane, Leeds, United Kingdom
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13
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Łysik D, Deptuła P, Chmielewska S, Skłodowski K, Pogoda K, Chin L, Song D, Mystkowska J, Janmey PA, Bucki R. Modulation of Biofilm Mechanics by DNA Structure and Cell Type. ACS Biomater Sci Eng 2022; 8:4921-4929. [PMID: 36301743 PMCID: PMC9667457 DOI: 10.1021/acsbiomaterials.2c00777] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
Deoxyribonucleic
acid (DNA) evolved as a tool for storing and transmitting
genetic information within cells, but outside the cell, DNA can also
serve as “construction material” present in microbial
biofilms or various body fluids, such as cystic fibrosis, sputum,
and pus. In the present work, we investigate the mechanics of biofilms
formed from Pseudomonas aeruginosa Xen
5, Staphylococcus aureus Xen 30, and Candida albicans 1408 using oscillatory shear rheometry
at different levels of compression and recreate these mechanics in
systems of entangled DNA and cells. The results show that the compression-stiffening
and shear-softening effects observed in biofilms can be reproduced
in DNA networks with the addition of an appropriate number of microbial
cells. Additionally, we observe that these effects are cell-type dependent.
We also identify other mechanisms that may significantly impact the
viscoelastic behavior of biofilms, such as the compression-stiffening
effect of DNA cross-linking by bivalent cations (Mg2+,
Ca2+, and Cu2+) and the stiffness-increasing
interactions of P. aeruginosa Xen 5
biofilm with Pf1 bacteriophage produced by P. aeruginosa. This work extends the knowledge of biofilm mechanobiology and demonstrates
the possibility of modifying biopolymers toward obtaining the desired
biophysical properties.
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Affiliation(s)
- Dawid Łysik
- Institute of Biomedical Engineering, Bialystok University of Technology, 15-351 Bialystok, Poland
| | - Piotr Deptuła
- Department of Medical Microbiology and Nanobiomedical Engineering, Medical University of Bialystok, 15-222 Bialystok, Poland
| | - Sylwia Chmielewska
- Department of Medical Microbiology and Nanobiomedical Engineering, Medical University of Bialystok, 15-222 Bialystok, Poland
| | - Karol Skłodowski
- Department of Medical Microbiology and Nanobiomedical Engineering, Medical University of Bialystok, 15-222 Bialystok, Poland
| | - Katarzyna Pogoda
- Institute of Nuclear Physics, Polish Academy of Sciences, 31-342 Krakow, Poland
| | - LiKang Chin
- Department of Biomedical Engineering, Widener University, Chester, Pennsylvania 19087, United States
| | - Dawei Song
- Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Joanna Mystkowska
- Institute of Biomedical Engineering, Bialystok University of Technology, 15-351 Bialystok, Poland
| | - Paul A. Janmey
- Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Robert Bucki
- Department of Medical Microbiology and Nanobiomedical Engineering, Medical University of Bialystok, 15-222 Bialystok, Poland
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14
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Guillaume O, Butnarasu C, Visentin S, Reimhult E. Interplay between biofilm microenvironment and pathogenicity of Pseudomonas aeruginosa in cystic fibrosis lung chronic infection. Biofilm 2022; 4:100089. [PMID: 36324525 PMCID: PMC9618985 DOI: 10.1016/j.bioflm.2022.100089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 10/14/2022] [Accepted: 10/17/2022] [Indexed: 11/07/2022] Open
Abstract
Pseudomonas aeruginosa (PA) is a highly, if not the most, versatile microorganism capable of colonizing diverse environments. One of the niches in which PA is able to thrive is the lung of cystic fibrosis (CF) patients. Due to a genetic aberration, the lungs of CF-affected patients exhibit impaired functions, rendering them highly susceptible to bacterial colonization. Once PA attaches to the epithelial surface and transitions to a mucoid phenotype, the infection becomes chronic, and antibiotic treatments become inefficient. Due to the high number of affected people and the severity of this infection, CF-chronic infection is a well-documented disease. Still, numerous aspects of PA CF infection remain unclear. The scientific reports published over the last decades have stressed how PA can adapt to CF microenvironmental conditions and how its surrounding matrix of extracellular polymeric substances (EPS) plays a key role in its pathogenicity. In this context, it is of paramount interest to present the nature of the EPS together with the local CF-biofilm microenvironment. We review how the PA biofilm microenvironment interacts with drugs to contribute to the pathogenicity of CF-lung infection. Understanding why so many drugs are inefficient in treating CF chronic infection while effectively treating planktonic PA is essential to devising better therapeutic targets and drug formulations.
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Affiliation(s)
- Olivier Guillaume
- 3D Printing and Biofabrication Group, Institute of Materials Science and Technology, TU Wien (Technische Universität Wien), Getreidemarkt 9/308, 1060, Vienna, Austria,Austrian Cluster for Tissue Regeneration, Austria,Corresponding author. 3D Printing and Biofabrication Group, Institute of Materials Science and Technology, TU Wien (Technische Universität Wien), Getreidemarkt 9/308, 1060, Vienna, Austria.
| | - Cosmin Butnarasu
- Department of Molecular Biotechnology and Health Science, University of Turin, Turin, 10135, Italy
| | - Sonja Visentin
- Department of Molecular Biotechnology and Health Science, University of Turin, Turin, 10135, Italy
| | - Erik Reimhult
- Institute of Biologically Inspired Materials, Department of Nanobiotechnology, University of Natural Resources and Life Sciences Vienna, Muthgasse 11, 1190, Vienna, Austria
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15
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Hills OJ, Yong CW, Scott AJ, Smith J, Chappell HF. Polyguluronate simulations shed light onto the therapeutic action of OligoG CF-5/20. Bioorg Med Chem 2022; 72:116945. [PMID: 36037625 DOI: 10.1016/j.bmc.2022.116945] [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: 05/30/2022] [Revised: 07/19/2022] [Accepted: 07/21/2022] [Indexed: 11/25/2022]
Abstract
Chronic mucoid P. aeruginosa cystic fibrosis (CF) lung infections are associated with the development of a biofilm composed of anionic acetylated exopolysaccharide (EPS) alginate, electrostatically stabilised by extracellular Ca2+ ions. OligoG CF-5/20, a low molecular weight guluronate rich oligomer, is emerging as a novel therapeutic capable of disrupting mature P. aeruginosa biofilms. However, its method of therapeutic action on the mucoid biofilm EPS is not definitively known at a molecular level. This work, utilising molecular dynamics (MD) and Density-Functional Theory (DFT), has revealed that OligoG CF-5/20 interaction with the EPS is facilitated solely through bridging Ca2+ ions, which are not liberated from their native EPS binding sites upon OligoG CF-5/20 dispersal, suggesting that OligoG CF-5/20 does not cause disruptions to mature P. aeruginosa biofilms through breaking EPS-Ca2+-EPS ionic cross-links. Rather it is likely that the therapeutic activity arises from sequestering free Ca2+ ions and preventing further Ca2+ induced EPS aggregation.
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Affiliation(s)
- Oliver J Hills
- School of Food Science & Nutrition, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, UK
| | - Chin W Yong
- Scientific Computing Department, Science and Technology Facilities Council, Daresbury Laboratory, Keckwick Lane, Daresbury, Warrington, WA4 4AD, UK; Division of Pharmacy and Optometry, School of Health Sciences, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Andrew J Scott
- School of Chemical & Process Engineering, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, UK
| | - James Smith
- School of Food Science & Nutrition, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, UK
| | - Helen F Chappell
- School of Food Science & Nutrition, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, UK.
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16
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Physiological Effects of Ferroptosis on Organ Fibrosis. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:5295434. [PMID: 36238649 PMCID: PMC9553398 DOI: 10.1155/2022/5295434] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 09/12/2022] [Accepted: 09/14/2022] [Indexed: 12/16/2022]
Abstract
Ferroptosis is a new type of programmed cell death with unique morphological, biochemical, and genetic features. From the initial study of histomorphology to the exploration of subcellular organelles and even molecular mechanisms, a net connecting ferroptosis and fibrosis is being woven and formed. Inflammation may be the bridge between both processes. In this review, we will discuss the ferroptosis theory and process and the physiological functions of ferroptosis, followed by a description of the pathological effects and the underlying mechanisms of ferroptosis in the pathogenesis of tumorigenesis, ischemic damage, degenerative lesions, autoimmune diseases, and necroinflammation. We then focus on the role of ferroptosis in the fibrosis process in the liver, lung, kidney, heart, and other organs. Although the molecular mechanism of ferroptosis has been explored extensively in the past few years, many challenges remain to be resolved to translate this information into antifibrotic practice, which is becoming a promising new direction in the field of fibrotic disease prevention and treatment.
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17
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Rajput A, Tsunemoto H, Sastry AV, Szubin R, Rychel K, Chauhan SM, Pogliano J, Palsson BO. Advanced transcriptomic analysis reveals the role of efflux pumps and media composition in antibiotic responses of Pseudomonas aeruginosa. Nucleic Acids Res 2022; 50:9675-9688. [PMID: 36095122 PMCID: PMC9508857 DOI: 10.1093/nar/gkac743] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 08/06/2022] [Accepted: 09/06/2022] [Indexed: 11/14/2022] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen and major cause of hospital-acquired infections. The virulence of P. aeruginosa is largely determined by its transcriptional regulatory network (TRN). We used 411 transcription profiles of P. aeruginosa from diverse growth conditions to construct a quantitative TRN by identifying independently modulated sets of genes (called iModulons) and their condition-specific activity levels. The current study focused on the use of iModulons to analyze the biofilm production and antibiotic resistance of P. aeruginosa. Our analysis revealed: (i) 116 iModulons, 81 of which show strong association with known regulators; (ii) novel roles of regulators in modulating antibiotics efflux pumps; (iii) substrate-efflux pump associations; (iv) differential iModulon activity in response to beta-lactam antibiotics in bacteriological and physiological media; (v) differential activation of 'Cell Division' iModulon resulting from exposure to different beta-lactam antibiotics and (vi) a role of the PprB iModulon in the stress-induced transition from planktonic to biofilm lifestyle. In light of these results, the construction of an iModulon-based TRN provides a transcriptional regulatory basis for key aspects of P. aeruginosa infection, such as antibiotic stress responses and biofilm formation. Taken together, our results offer a novel mechanistic understanding of P. aeruginosa virulence.
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Affiliation(s)
- Akanksha Rajput
- Department of Bioengineering, University of California, San Diego, La Jolla, CA, USA
| | - Hannah Tsunemoto
- Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Anand V Sastry
- Department of Bioengineering, University of California, San Diego, La Jolla, CA, USA
| | - Richard Szubin
- Department of Bioengineering, University of California, San Diego, La Jolla, CA, USA
| | - Kevin Rychel
- Department of Bioengineering, University of California, San Diego, La Jolla, CA, USA
| | - Siddharth M Chauhan
- Department of Bioengineering, University of California, San Diego, La Jolla, CA, USA
| | - Joe Pogliano
- Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Bernhard O Palsson
- Department of Bioengineering, University of California, San Diego, La Jolla, CA, USA.,Department of Pediatrics, University of California, San Diego, La Jolla, CA, USA.,Center for Microbiome Innovation, University of California San Diego, La Jolla, CA 92093, USA.,Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet, Building 220, 2800 Kongens, Lyngby, Denmark
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18
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Ruhluel D, O'Brien S, Fothergill JL, Neill DR. Development of liquid culture media mimicking the conditions of sinuses and lungs in cystic fibrosis and health. F1000Res 2022; 11:1007. [PMID: 36519007 PMCID: PMC9718992 DOI: 10.12688/f1000research.125074.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/18/2022] [Indexed: 11/25/2023] Open
Abstract
The respiratory tract is a compartmentalised and heterogenous environment. The nasopharynx and sinuses of the upper airways have distinct properties from the lungs and these differences may shape bacterial adaptation and evolution. Upper airway niches act as early colonisation sites for respiratory bacterial pathogens, including those, such as Pseudomonas aeruginosa, that can go on to establish chronic infection of the lungs in people with cystic fibrosis (CF). Despite the importance of upper airway environments in facilitating early adaptation to host environments, currently available in vitro models for study of respiratory infection in CF focus exclusively on the lungs. Furthermore, animal models, widely used to bridge the gap between in vitro systems and the clinical scenario, do not allow the upper and lower airways to be studied in isolation. We have developed a suite of culture media reproducing key features of the upper and lower airways, for the study of bacterial adaptation and evolution in different respiratory environments. For both upper and lower airway-mimicking media, we have developed formulations that reflect airway conditions in health and those that reflect the altered environment of the CF respiratory tract. Here, we describe the development and validation of these media and their use for study of genetic and phenotypic adaptations in P. aeruginosa during growth under upper or lower airway conditions in health and in CF.
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Affiliation(s)
- Dilem Ruhluel
- University of Liverpool, Institute of Infection, Veterinary and Ecological Sciences,, Liverpool, L69 7BE, UK
| | - Siobhan O'Brien
- Department of Microbiology, Moyne Institute of Preventive Medicine, Trinity College, Dublin, 2, Ireland
| | - Joanne L Fothergill
- University of Liverpool, Institute of Infection, Veterinary and Ecological Sciences,, Liverpool, L69 7BE, UK
| | - Daniel R Neill
- University of Liverpool, Institute of Infection, Veterinary and Ecological Sciences,, Liverpool, L69 7BE, UK
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19
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Kayastha BB, Kubo A, Burch-Konda J, Dohmen RL, McCoy JL, Rogers RR, Mares S, Bevere J, Huckaby A, Witt W, Peng S, Chaudhary B, Mohanty S, Barbier M, Cook G, Deng J, Patrauchan MA. EF-hand protein, EfhP, specifically binds Ca 2+ and mediates Ca 2+ regulation of virulence in a human pathogen Pseudomonas aeruginosa. Sci Rep 2022; 12:8791. [PMID: 35614085 PMCID: PMC9132961 DOI: 10.1038/s41598-022-12584-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 05/09/2022] [Indexed: 11/30/2022] Open
Abstract
Calcium (Ca2+) is well known as a second messenger in eukaryotes, where Ca2+ signaling controls life-sustaining cellular processes. Although bacteria produce the components required for Ca2+ signaling, little is known about the mechanisms of bacterial Ca2+ signaling. Previously, we have identified a putative Ca2+-binding protein EfhP (PA4107) with two canonical EF-hand motifs and reported that EfhP mediates Ca2+ regulation of virulence factors production and infectivity in Pseudomonas aeruginosa, a human pathogen causing life-threatening infections. Here, we show that EfhP selectively binds Ca2+ with 13.7 µM affinity, and that mutations at the +X and -Z positions within each or both EF-hand motifs abolished Ca2+ binding. We also show that the hydrophobicity of EfhP increased in a Ca2+-dependent manner, however no such response was detected in the mutated proteins. 15 N-NMR showed Ca2+-dependent chemical shifts in EfhP confirming Ca2+-binding triggered structural rearrangements in the protein. Deletion of efhP impaired P. aeruginosa survival in macrophages and virulence in vivo. Disabling EfhP Ca2+ binding abolished Ca2+ induction of pyocyanin production in vitro. These data confirm that EfhP selectively binds Ca2+, which triggers its structural changes required for the Ca2+ regulation of P. aeruginosa virulence, thus establishing the role of EfhP as a Ca2+ sensor.
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Affiliation(s)
- Biraj B Kayastha
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Aya Kubo
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Jacob Burch-Konda
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Rosalie L Dohmen
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Jacee L McCoy
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Rendi R Rogers
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Sergio Mares
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Justin Bevere
- Vaccine Development Center at West Virginia University, Morgantown, WV, 26506, USA
- Department of Microbiology, Immunology and Cell Biology, West Virginia University, Morgantown, WV, 26506, USA
| | - Annalisa Huckaby
- Vaccine Development Center at West Virginia University, Morgantown, WV, 26506, USA
- Department of Microbiology, Immunology and Cell Biology, West Virginia University, Morgantown, WV, 26506, USA
| | - William Witt
- Vaccine Development Center at West Virginia University, Morgantown, WV, 26506, USA
- Department of Microbiology, Immunology and Cell Biology, West Virginia University, Morgantown, WV, 26506, USA
| | - Shuxia Peng
- Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Bharat Chaudhary
- Department of Chemistry, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Smita Mohanty
- Department of Chemistry, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Mariette Barbier
- Vaccine Development Center at West Virginia University, Morgantown, WV, 26506, USA
- Department of Microbiology, Immunology and Cell Biology, West Virginia University, Morgantown, WV, 26506, USA
| | - Gabriel Cook
- Department of Chemistry, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Junpeng Deng
- Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Marianna A Patrauchan
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, 74078, USA.
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20
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Hills OJ, Yong CW, Scott AJ, Devine DA, Smith J, Chappell HF. Atomic-scale interactions between quorum sensing autoinducer molecules and the mucoid P. aeruginosa exopolysaccharide matrix. Sci Rep 2022; 12:7724. [PMID: 35545629 PMCID: PMC9095684 DOI: 10.1038/s41598-022-11499-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 04/18/2022] [Indexed: 12/22/2022] Open
Abstract
Mucoid Pseudomonas aeruginosa is a prevalent cystic fibrosis (CF) lung coloniser whose chronicity is associated with the formation of cation cross-linked exopolysaccharide (EPS) matrices, which form a biofilm that acts as a diffusion barrier, sequestering cationic and neutral antimicrobials, and making it extremely resistant to pharmacological challenge. Biofilm chronicity and virulence of the colony is regulated by quorum sensing autoinducers (QSAIs), small signalling metabolites that pass between bacteria, through the biofilm matrix, regulating genetic responses on a population-wide scale. The nature of how these molecules interact with the EPS is poorly understood, despite the fact that they must pass through EPS matrix to reach neighbouring bacteria. Interactions at the atomic-scale between two QSAI molecules, C4-HSL and PQS—both utilised by mucoid P. aeruginosa in the CF lung—and the EPS, have been studied for the first time using a combined molecular dynamics (MD) and density functional theory (DFT) approach. A large-scale, calcium cross-linked, multi-chain EPS molecular model was developed and MD used to sample modes of interaction between QSAI molecules and the EPS that occur at physiological equilibrium. The thermodynamic stability of the QSAI-EPS adducts were calculated using DFT. These simulations provide a thermodynamic rationale for the apparent free movement of C4-HSL, highlight key molecular functionality responsible for EPS binding and, based on its significantly reduced mobility, suggest PQS as a viable target for quorum quenching.
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Affiliation(s)
- Oliver J Hills
- School of Food Science & Nutrition, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK.
| | - Chin W Yong
- Daresbury Laboratory, Scientific Computing Department, Science and Technology Facilities Council, Keckwick Lane, Daresbury, Warrington, WA4 4AD, UK.,Division of Pharmacy and Optometry, School of Health Sciences, University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Andrew J Scott
- School of Chemical & Process Engineering, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK
| | - Deirdre A Devine
- School of Dentistry, University of Leeds, Clarendon Way, Leeds, LS2 9LU, UK
| | - James Smith
- School of Food Science & Nutrition, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK
| | - Helen F Chappell
- School of Food Science & Nutrition, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK.
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21
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Mucoid Pseudomonas aeruginosa Can Produce Calcium-Gelled Biofilms Independent of the Matrix Components Psl and CdrA. J Bacteriol 2022; 204:e0056821. [PMID: 35416688 PMCID: PMC9112934 DOI: 10.1128/jb.00568-21] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Biofilms are aggregates of microorganisms embedded in an extracellular matrix comprised largely of exopolysaccharides (EPSs), nucleic acids, and proteins. Pseudomonas aeruginosa is an opportunistic human pathogen that is also a model organism for studying biofilms in the laboratory. Here, we define a novel program of biofilm development used by mucoid (alginate-overproducing) P. aeruginosa in the presence of elevated calcium. Calcium cations cross-link negatively charged alginate polymers, resulting in individual cells being suspended in an alginate gel. The formation of this type of structurally distinct biofilm is not reliant on the canonical biofilm EPS components Psl and Pel or the matrix protein CdrA. We also observed that mucoid P. aeruginosa biofilm cells do not have the typical elevated levels of the secondary messenger cyclic di-GMP (c-di-GMP), as expected of biofilm cells, nor does the overproduction of alginate rely on high c-di-GMP. This contrasts with nonmucoid biofilms in which the production of the matrix components Psl, Pel, and CdrA is positively regulated by elevated c-di-GMP. We further demonstrate that calcium-gelled alginate biofilms impede the penetration of the antibiotic tobramycin, thus protecting the biofilm community from antibiotic-mediated killing. Finally, we show that bacterial aggregates with a dispersed cell arrangement like laboratory-grown calcium-alginate biofilm structures are present in explanted cystic fibrosis (CF) lung samples. Our findings illustrate the diverse nature of biofilm formation and structure in P. aeruginosa. IMPORTANCE The opportunistic pathogen Pseudomonas aeruginosa produces a complex biofilm matrix comprised of exopolysaccharides (EPSs), nucleic acids, and proteins. P. aeruginosa biofilm formation canonically depends on a variable combination of the exopolysaccharides Psl and Pel and the matrix protein CdrA. We demonstrate that mucoid P. aeruginosa, which overproduces the EPS alginate, possesses an entirely alternate and calcium-dependent method of biofilm formation. These mucoid biofilm structures do not require Psl, Pel, or CdrA, and they display a unique organization of individually suspended cells similar to bacterial aggregates observed in cystic fibrosis airways. Furthermore, calcium-gelled mucoid biofilms impede the penetration and killing action of the antibiotic tobramycin, illustrating their potential clinical significance. Our findings highlight the compositional and structural variety of P. aeruginosa biofilm aggregates.
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22
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Rajput A, Tsunemoto H, Sastry AV, Szubin R, Rychel K, Sugie J, Pogliano J, Palsson BO. Machine learning from Pseudomonas aeruginosa transcriptomes identifies independently modulated sets of genes associated with known transcriptional regulators. Nucleic Acids Res 2022; 50:3658-3672. [PMID: 35357493 PMCID: PMC9023270 DOI: 10.1093/nar/gkac187] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 02/28/2022] [Accepted: 03/29/2022] [Indexed: 12/16/2022] Open
Abstract
The transcriptional regulatory network (TRN) of Pseudomonas aeruginosa coordinates cellular processes in response to stimuli. We used 364 transcriptomes (281 publicly available + 83 in-house generated) to reconstruct the TRN of P. aeruginosa using independent component analysis. We identified 104 independently modulated sets of genes (iModulons) among which 81 reflect the effects of known transcriptional regulators. We identified iModulons that (i) play an important role in defining the genomic boundaries of biosynthetic gene clusters (BGCs), (ii) show increased expression of the BGCs and associated secretion systems in nutrient conditions that are important in cystic fibrosis, (iii) show the presence of a novel ribosomally synthesized and post-translationally modified peptide (RiPP) BGC which might have a role in P. aeruginosa virulence, (iv) exhibit interplay of amino acid metabolism regulation and central metabolism across different carbon sources and (v) clustered according to their activity changes to define iron and sulfur stimulons. Finally, we compared the identified iModulons of P. aeruginosa with those previously described in Escherichia coli to observe conserved regulons across two Gram-negative species. This comprehensive TRN framework encompasses the majority of the transcriptional regulatory machinery in P. aeruginosa, and thus should prove foundational for future research into its physiological functions.
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Affiliation(s)
- Akanksha Rajput
- Department of Bioengineering, University of California, San Diego, La Jolla, USA
| | - Hannah Tsunemoto
- Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Anand V Sastry
- Department of Bioengineering, University of California, San Diego, La Jolla, USA
| | - Richard Szubin
- Department of Bioengineering, University of California, San Diego, La Jolla, USA
| | - Kevin Rychel
- Department of Bioengineering, University of California, San Diego, La Jolla, USA
| | - Joseph Sugie
- Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Joe Pogliano
- Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Bernhard O Palsson
- Department of Bioengineering, University of California, San Diego, La Jolla, USA.,Department of Pediatrics, University of California, San Diego, La Jolla, CA, USA.,Center for Microbiome Innovation, University of California San Diego, La Jolla, CA 92093, USA.,Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet, Building 220, 2800 Kongens, Lyngby, Denmark
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23
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Belardinelli JM, Li W, Martin KH, Zeiler MJ, Lian E, Avanzi C, Wiersma CJ, Nguyen TV, Angala B, de Moura VCN, Jones V, Borlee BR, Melander C, Jackson M. 2-Aminoimidazoles Inhibit Mycobacterium abscessus Biofilms in a Zinc-Dependent Manner. Int J Mol Sci 2022; 23:ijms23062950. [PMID: 35328372 PMCID: PMC8951752 DOI: 10.3390/ijms23062950] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 02/28/2022] [Accepted: 03/07/2022] [Indexed: 02/04/2023] Open
Abstract
Biofilm growth is thought to be a significant obstacle to the successful treatment of Mycobacterium abscessus infections. A search for agents capable of inhibiting M. abscessus biofilms led to our interest in 2-aminoimidazoles and related scaffolds, which have proven to display antibiofilm properties against a number of Gram-negative and Gram-positive bacteria, including Mycobacterium tuberculosis and Mycobacterium smegmatis. The screening of a library of 30 compounds led to the identification of a compound, AB-2-29, which inhibits the formation of M. abscessus biofilms with an IC50 (the concentration required to inhibit 50% of biofilm formation) in the range of 12.5 to 25 μM. Interestingly, AB-2-29 appears to chelate zinc, and its antibiofilm activity is potentiated by the addition of zinc to the culture medium. Preliminary mechanistic studies indicate that AB-2-29 acts through a distinct mechanism from those reported to date for 2-aminoimidazole compounds.
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Affiliation(s)
- Juan M. Belardinelli
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, USA; (J.M.B.); (W.L.); (E.L.); (C.A.); (C.J.W.); (B.A.); (V.C.N.d.M.); (V.J.)
| | - Wei Li
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, USA; (J.M.B.); (W.L.); (E.L.); (C.A.); (C.J.W.); (B.A.); (V.C.N.d.M.); (V.J.)
| | - Kevin H. Martin
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, USA; (K.H.M.); (B.R.B.)
| | - Michael J. Zeiler
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA; (M.J.Z.); (C.M.)
| | - Elena Lian
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, USA; (J.M.B.); (W.L.); (E.L.); (C.A.); (C.J.W.); (B.A.); (V.C.N.d.M.); (V.J.)
| | - Charlotte Avanzi
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, USA; (J.M.B.); (W.L.); (E.L.); (C.A.); (C.J.W.); (B.A.); (V.C.N.d.M.); (V.J.)
| | - Crystal J. Wiersma
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, USA; (J.M.B.); (W.L.); (E.L.); (C.A.); (C.J.W.); (B.A.); (V.C.N.d.M.); (V.J.)
| | - Tuan Vu Nguyen
- Department of Chemistry, North Carolina State University, Raleigh, NC 27607, USA;
| | - Bhanupriya Angala
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, USA; (J.M.B.); (W.L.); (E.L.); (C.A.); (C.J.W.); (B.A.); (V.C.N.d.M.); (V.J.)
| | - Vinicius C. N. de Moura
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, USA; (J.M.B.); (W.L.); (E.L.); (C.A.); (C.J.W.); (B.A.); (V.C.N.d.M.); (V.J.)
| | - Victoria Jones
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, USA; (J.M.B.); (W.L.); (E.L.); (C.A.); (C.J.W.); (B.A.); (V.C.N.d.M.); (V.J.)
| | - Bradley R. Borlee
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, USA; (K.H.M.); (B.R.B.)
| | - Christian Melander
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA; (M.J.Z.); (C.M.)
- Department of Chemistry, North Carolina State University, Raleigh, NC 27607, USA;
| | - Mary Jackson
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, USA; (J.M.B.); (W.L.); (E.L.); (C.A.); (C.J.W.); (B.A.); (V.C.N.d.M.); (V.J.)
- Correspondence: ; Tel.: +1-(970)-491-3582
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Ruhluel D, O'Brien S, Fothergill JL, Neill DR. Development of liquid culture media mimicking the conditions of sinuses and lungs in cystic fibrosis and health. F1000Res 2022; 11:1007. [PMID: 36519007 PMCID: PMC9718992 DOI: 10.12688/f1000research.125074.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/18/2022] [Indexed: 12/05/2022] Open
Abstract
The respiratory tract is a compartmentalised and heterogenous environment. The nasopharynx and sinuses of the upper airways have distinct properties from the lungs and these differences may shape bacterial adaptation and evolution. Upper airway niches act as early colonisation sites for respiratory bacterial pathogens, including those, such as Pseudomonas aeruginosa, that can go on to establish chronic infection of the lungs in people with cystic fibrosis (CF). Despite the importance of upper airway environments in facilitating early adaptation to host environments, currently available in vitro models for study of respiratory infection in CF focus exclusively on the lungs. Furthermore, animal models, widely used to bridge the gap between in vitro systems and the clinical scenario, do not allow the upper and lower airways to be studied in isolation. We have developed a suite of culture media reproducing key features of the upper and lower airways, for the study of bacterial adaptation and evolution in different respiratory environments. For both upper and lower airway-mimicking media, we have developed formulations that reflect airway conditions in health and those that reflect the altered environment of the CF respiratory tract. Here, we describe the development and validation of these media and their use for study of genetic and phenotypic adaptations in P. aeruginosa during growth under upper or lower airway conditions in health and in CF.
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Affiliation(s)
- Dilem Ruhluel
- University of Liverpool, Institute of Infection, Veterinary and Ecological Sciences,, Liverpool, L69 7BE, UK
| | - Siobhan O'Brien
- Department of Microbiology, Moyne Institute of Preventive Medicine, Trinity College, Dublin, 2, Ireland
| | - Joanne L Fothergill
- University of Liverpool, Institute of Infection, Veterinary and Ecological Sciences,, Liverpool, L69 7BE, UK
| | - Daniel R Neill
- University of Liverpool, Institute of Infection, Veterinary and Ecological Sciences,, Liverpool, L69 7BE, UK
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25
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Maniam P, Essilfie AT, Kalimutho M, Ling D, Frazer DM, Phipps S, Anderson GJ, Reid DW. Increased susceptibility of cystic fibrosis airway epithelial cells to ferroptosis. Biol Res 2021; 54:38. [PMID: 34903297 PMCID: PMC8670191 DOI: 10.1186/s40659-021-00361-3] [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: 09/02/2021] [Accepted: 11/28/2021] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Defective chloride transport in airway epithelial cells (AECs) and the associated lung disease are the main causes of morbidity and early mortality in cystic fibrosis (CF). Abnormal airway iron homeostasis and the presence of lipid peroxidation products, indicative of oxidative stress, are features of CF lung disease. RESULTS Here, we report that CF AECs (IB3-1) are susceptible to ferroptosis, a type of cell death associated with iron accumulation and lipid peroxidation. Compared to isogenic CFTR corrected cells (C38), the IB3-1 cells showed increased susceptibility to cell death upon exposure to iron in the form of ferric ammonium citrate (FAC) and the ferroptosis inducer, erastin. This phenotype was accompanied by accumulation of intracellular ferrous iron and lipid peroxides and the extracellular release of malondialdehyde, all indicative of redox stress, and increased levels of lactate dehydrogenase in the culture supernatant, indicating enhanced cell injury. The ferric iron chelator deferoxamine (DFO) and the lipophilic antioxidant ferrostatin-1 inhibited FAC and erastin induced ferroptosis in IB3-1 cells. Glutathione peroxidase 4 (GPX4) expression was decreased in IB3-1 cells treated with FAC and erastin, but was unchanged in C38 AECs. Necroptosis appeared to be involved in the enhanced susceptibility of IB3-1 AECs to ferroptosis, as evidenced by partial cell death rescue with necroptosis inhibitors and enhanced mixed lineage kinase domain-like (MLKL) localisation to the plasma membrane. CONCLUSION These studies suggest that the increased susceptibility of CF AECs to ferroptosis is linked to abnormal intracellular ferrous iron accumulation and reduced antioxidant defences. In addition, the process of ferroptotic cell death in CF AECs does not appear to be a single entity and for the first time we describe necroptosis as a potential contributory factor. Iron chelation and antioxidant treatments may be promising therapeutic interventions in cystic fibrosis.
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Affiliation(s)
- Pramila Maniam
- Immunology Department, QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Ama-Tawiah Essilfie
- Immunology Department, QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Murugan Kalimutho
- Cell and Molecular Biology Department, QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Dora Ling
- Immunology Department, QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - David M Frazer
- Cell and Molecular Biology Department, QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Simon Phipps
- Immunology Department, QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Gregory J Anderson
- Cell and Molecular Biology Department, QIMR Berghofer Medical Research Institute, Brisbane, Australia
- School of Chemistry and Molecular Bioscience, University of Queensland, St Lucia, Australia
| | - David W Reid
- Immunology Department, QIMR Berghofer Medical Research Institute, Brisbane, Australia.
- Adult Cystic Fibrosis Centre, The Prince Charles Hospital, Chermside, Australia.
- Lung Inflammation and Infection Laboratory, Immunology Department, QIMR Berghofer Medical Research Institute, Herston, QLD, 4003, Australia.
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Lepissier A, Addy C, Hayes K, Noel S, Bui S, Burgel PR, Dupont L, Eickmeier O, Fayon M, Leal T, Lopes C, Downey DG, Sermet-Gaudelus I. Inflammation biomarkers in sputum for clinical trials in cystic fibrosis: current understanding and gaps in knowledge. J Cyst Fibros 2021; 21:691-706. [PMID: 34772643 DOI: 10.1016/j.jcf.2021.10.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 10/25/2021] [Accepted: 10/25/2021] [Indexed: 12/12/2022]
Abstract
RATIONALE Sputum biomarkers hold promise as a direct measure of inflammation within the cystic fibrosis (CF) lung, but variability in study design and sampling methodology have limited their use. A full evaluation of the reliability, validity and clinical relevance of individual biomarkers is required to optimise their use within CF clinical research. OBJECTIVES A biomarker Special Interest Working Group was established within the European Cystic Fibrosis Society-Clinical Trials Network Standardisation Committee, to perform a review of the evidence regarding sputum biomarkers in CF. METHODS From the 139 included articles, we identified 71 sputum biomarkers to undergo evaluation of their clinimetric properties, responsiveness, discriminant, concurrent and convergent validity. RESULTS Current evidence confirms the potential of sputum biomarkers as outcome measures in clinical trials. Inconsistency in responsiveness, concurrent and convergent validity require further research into these markers and processing standardisation before translation into wider use. Of the 71 biomarkers identified, Neutrophil Elastase (NE), IL-8, TNF-α and IL-1β, demonstrated validity and responsiveness to be currently considered for use in clinical trials. Other biomarkers show future promise, including IL-6, calprotectin, HMGB-1 and YKL-40. CONCLUSION A concerted international effort across the cystic fibrosis community is needed to promote high quality biomarker trial design, establish large population-based biomarker studies, and work together to create standards for collection, storage and analysis of sputum biomarkers.
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Affiliation(s)
- Agathe Lepissier
- Paediatric Center for Cystic Fibrosis, Centre de Référence Maladies Rares, Mucoviscidose et Maladies Apparentées, Hôpital Necker Enfants Malades 149 rue de Sévres, Paris 75743, France; INSERM U1151, Institut Necker Enfants Malades, 160 rue de Vaugirard, Paris 75743, France; European Reference Network (ERN Lung)
| | - Charlotte Addy
- Northern Ireland Clinical Research Facility, Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7BL; All Wales Adult Cystic Fibrosis Centre, University Hopsital Llandough, Penlan Road, CF64 2XX
| | - Kate Hayes
- Northern Ireland Clinical Research Facility, Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7BL
| | - Sabrina Noel
- INSERM U1151, Institut Necker Enfants Malades, 160 rue de Vaugirard, Paris 75743, France
| | - Stéphanie Bui
- Université de Bordeaux (INSERM U1045), CHU de Bordeaux, (CIC1401), F-33000 Bordeaux, France
| | - Pierre-Régis Burgel
- European Reference Network (ERN Lung); National Reference Cystic Fibrosis Center and Department of Respiratory Medicine, Cochin Hospital, Assistance Publique Hôpitaux de Paris, Paris, 75014, France; Institut Cochin, INSERM U1016 and Université de Paris; Paris 75014, France
| | - Lieven Dupont
- University Hospital Gasthuisberg, Herestraat 49, 3000 Leuven, Belgium
| | - Olaf Eickmeier
- Facharzt für Kinder- und Jugendmedizin, Universitätsklinikum Frankfurt a.M., Johann Wolfgang-Goethe-Universität, Allergologie, Pneumologie & Mukoviszidose, Theodor-Stern-Kai 7, 60590 Frankfurt/Main
| | - Michael Fayon
- Université de Bordeaux (INSERM U1045), CHU de Bordeaux, (CIC1401), F-33000 Bordeaux, France
| | - Teresinha Leal
- Louvain Toxicology and Applied Pharmacology, Institut de Recherche Expérimentale et Clinique, Université Catholique de Louvain, Brussels, Belgium
| | - Carlos Lopes
- Departamento do Tórax, Hospital de Santa Maria, Lisbon
| | - Damian G Downey
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7BL
| | - Isabelle Sermet-Gaudelus
- Paediatric Center for Cystic Fibrosis, Centre de Référence Maladies Rares, Mucoviscidose et Maladies Apparentées, Hôpital Necker Enfants Malades 149 rue de Sévres, Paris 75743, France; INSERM U1151, Institut Necker Enfants Malades, 160 rue de Vaugirard, Paris 75743, France; European Reference Network (ERN Lung); Service de Pneumologie et Allergologie Pédiatriques, Centre de Ressources et de Compétence de la Mucoviscidose, Hôpital Necker Enfants Malades 149 rue de Sévres, INSERM U1151, Institut Necker Enfants Malades, Université Paris Sorbonne, Paris 75743, France.
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27
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Lewin A, Kamal E, Semmler T, Winter K, Kaiser S, Schäfer H, Mao L, Eschenhagen P, Grehn C, Bender J, Schwarz C. Genetic diversification of persistent Mycobacterium abscessus within cystic fibrosis patients. Virulence 2021; 12:2415-2429. [PMID: 34546836 PMCID: PMC8526041 DOI: 10.1080/21505594.2021.1959808] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Mycobacterium (M.) abscessus infections in Cystic Fibrosis (CF) patients cause a deterioration of lung function. Treatment of these multidrug-resistant pathogens is associated with severe side-effects, while frequently unsuccessful. Insight on M. abscessus genomic evolvement during chronic lung infection would be beneficial for improving treatment strategies. A longitudinal study enrolling 42 CF patients was performed at a CF center in Berlin, Germany, to elaborate phylogeny and genomic diversification of in-patient M. abscessus. Eleven of the 42 CF patients were infected with M. abscessus. Five of these 11 patients were infected with global human-transmissible M. abscessus cluster strains. Phylogenetic analysis of 88 genomes from isolates of the 11 patients excluded occurrence of M. abscessus transmission among members of the study group. Genome sequencing and variant analysis of 30 isolates from 11 serial respiratory samples collected over 4.5 years from a chronically infected patient demonstrated accumulation of gene mutations. In total, 53 genes exhibiting non-synonymous variations were identified. Enrichment analysis emphasized genes involved in synthesis of glycopeptidolipids, genes from the embABC (arabinosyltransferase) operon, betA (glucose-methanol-choline oxidoreductase) and choD (cholesterol oxidase). Genetic diversity evolved in a variety of virulence- and resistance-associated genes. The strategy of M. abscessus populations in chronic lung infection is not clonal expansion of dominant variants, but to sustain simultaneously a wide range of genetic variants facilitating adaptation of the population to changing living conditions in the lung. Genomic diversification during chronic infection requires increased attention when new control strategies against M. abscessus infections are explored.
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Affiliation(s)
- Astrid Lewin
- Unit 16 Mycotic and Parasitic Agents and Mycobacteria, Robert Koch Institute, Berlin, Germany
| | - Elisabeth Kamal
- Unit 16 Mycotic and Parasitic Agents and Mycobacteria, Robert Koch Institute, Berlin, Germany
| | - Torsten Semmler
- Unit NG 1 Microbial Genomics, Robert Koch Institute, Berlin, Germany
| | - Katja Winter
- Unit MF1 Bioinformatics, Robert Koch Institute, Berlin, Germany
| | - Sandra Kaiser
- Unit MF1 Bioinformatics, Robert Koch Institute, Berlin, Germany
| | - Hubert Schäfer
- Unit 16 Mycotic and Parasitic Agents and Mycobacteria, Robert Koch Institute, Berlin, Germany
| | - Lei Mao
- Unit 16 Mycotic and Parasitic Agents and Mycobacteria, Robert Koch Institute, Berlin, Germany.,Unit 31 Infectious Disease Data Science Unit, Robert Koch Institute, Berlin, Germany
| | - Patience Eschenhagen
- Klinikum Westbrandenburg, Campus Potsdam, Cystic Fibrosis Section, Potsdam, Germany.,Pediatric Respiratory Medicine, Immunology and Intensive Care Medicine, Charité Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Claudia Grehn
- Department of Pediatrics, Division of Pulmonology, Immunology and Intensive Care Medicine, Division of Cystic Fibrosis, Charité - Universitätsmedizin, Berlin, Germany
| | - Jennifer Bender
- Unit 13 Nosocomial Pathogens and Antibiotic Resistances, Robert Koch Institute, Wernigerode, Germany.,ECDC Fellowship Programme, Public Health Microbiology Path (EUPHEM), European Centre for Disease Prevention and Control (ECDC), Solna, Sweden
| | - Carsten Schwarz
- Klinikum Westbrandenburg, Campus Potsdam, Cystic Fibrosis Section, Potsdam, Germany.,Pediatric Respiratory Medicine, Immunology and Intensive Care Medicine, Charité Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
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Cation complexation by mucoid Pseudomonas aeruginosa extracellular polysaccharide. PLoS One 2021; 16:e0257026. [PMID: 34473773 PMCID: PMC8412252 DOI: 10.1371/journal.pone.0257026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Accepted: 08/23/2021] [Indexed: 11/25/2022] Open
Abstract
Mucoid Pseudomonas aeruginosa is a prevalent cystic fibrosis (CF) lung colonizer, producing an extracellular matrix (ECM) composed predominantly of the extracellular polysaccharide (EPS) alginate. The ECM limits antimicrobial penetration and, consequently, CF sufferers are prone to chronic mucoid P. aeruginosa lung infections. Interactions between cations with elevated concentrations in the CF lung and the anionic EPS, enhance the structural rigidity of the biofilm and exacerbates virulence. In this work, two large mucoid P. aeruginosa EPS models, based on β-D-mannuronate (M) and β-D-mannuronate-α-L-guluronate systems (M-G), and encompassing thermodynamically stable acetylation configurations–a structural motif unique to mucoid P. aeruginosa–were created. Using highly accurate first principles calculations, stable coordination environments adopted by the cations have been identified and thermodynamic stability quantified. These models show the weak cross-linking capability of Na+ and Mg2+ ions relative to Ca2+ ions and indicate a preference for cation binding within M-G blocks due to the smaller torsional rearrangements needed to reveal stable binding sites. The geometry of the chelation site influences the stability of the resulting complexes more than electrostatic interactions, and the results show nuanced chemical insight into previous experimental observations.
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29
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Calprotectin-Mediated Zinc Chelation Inhibits Pseudomonas aeruginosa Protease Activity in Cystic Fibrosis Sputum. J Bacteriol 2021; 203:e0010021. [PMID: 33927050 DOI: 10.1128/jb.00100-21] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Pseudomonas aeruginosa induces pathways indicative of low zinc availability in the cystic fibrosis (CF) lung environment. To learn more about P. aeruginosa zinc access in CF, we grew P. aeruginosa strain PAO1 directly in expectorated CF sputum. The P. aeruginosa Zur transcriptional repressor controls the response to low intracellular zinc, and we used the NanoString methodology to monitor levels of Zur-regulated transcripts, including those encoding a zincophore system, a zinc importer, and paralogs of zinc containing proteins that do not require zinc for activity. Zur-controlled transcripts were induced in sputum-grown P. aeruginosa compared to those grown in control cultures but not if the sputum was amended with zinc. Amendment of sputum with ferrous iron did not reduce expression of Zur-regulated genes. A reporter fusion to a Zur-regulated promoter had variable activity in P. aeruginosa grown in sputum from different donors, and this variation inversely correlated with sputum zinc concentrations. Recombinant human calprotectin (CP), a divalent-metal binding protein released by neutrophils, was sufficient to induce a zinc starvation response in P. aeruginosa grown in laboratory medium or zinc-amended CF sputum, indicating that CP is functional in the sputum environment. Zinc metalloproteases comprise a large fraction of secreted zinc-binding P. aeruginosa proteins. Here, we show that recombinant CP inhibited both LasB-mediated casein degradation and LasA-mediated lysis of Staphylococcus aureus, which was reversible with added zinc. These studies reveal the potential for CP-mediated zinc chelation to posttranslationally inhibit zinc metalloprotease activity and thereby affect the protease-dependent physiology and/or virulence of P. aeruginosa in the CF lung environment. IMPORTANCE The factors that contribute to worse outcomes in individuals with cystic fibrosis (CF) with chronic Pseudomonas aeruginosa infections are not well understood. Therefore, there is a need to understand environmental factors within the CF airway that contribute to P. aeruginosa colonization and infection. We demonstrate that growing bacteria in CF sputum induces a zinc starvation response that inversely correlates with sputum zinc levels. Additionally, both calprotectin and a chemical zinc chelator inhibit the proteolytic activities of LasA and LasB proteases, suggesting that extracellular zinc chelators can influence proteolytic activity and thus P. aeruginosa virulence and nutrient acquisition in vivo.
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30
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Brown AC, Horvat JC. Casting Iron in the Pathogenesis of Fibrotic Lung Disease. Am J Respir Cell Mol Biol 2021; 65:130-131. [PMID: 33945773 PMCID: PMC8399580 DOI: 10.1165/rcmb.2021-0135ed] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- Alexandra C Brown
- Priority Research Centre for Healthy Lungs The University of Newcastle and Hunter Medical Research Institute Newcastle, New South Wales, Australia
| | - Jay C Horvat
- Priority Research Centre for Healthy Lungs The University of Newcastle and Hunter Medical Research Institute Newcastle, New South Wales, Australia
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31
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Forte G, Bocca B, Pisano A, Collu C, Farace C, Sabalic A, Senofonte M, Fois AG, Mazzarello VL, Pirina P, Madeddu R. The levels of trace elements in sputum as biomarkers for idiopathic pulmonary fibrosis. CHEMOSPHERE 2021; 271:129514. [PMID: 33434828 DOI: 10.1016/j.chemosphere.2020.129514] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Revised: 12/18/2020] [Accepted: 12/29/2020] [Indexed: 06/12/2023]
Abstract
Idiopathic pulmonary fibrosis (IPF) is a rare lung disease that quickly leads to death. This paper addressed the issue of whether the levels of trace elements in sputum samples are suitable biomarkers for IPF disease. The sputum Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn concentrations were measured by sector field inductively coupled plasma mass spectrometry in populations sampled in Sardinia Island (Italy) including 31 patients with IPF, 31 patients with other lung-related diseases and 30 age- and gender-matched healthy controls. Risk factors in the disease as gender, age, severity and duration of the disease were assessed. Results showed that IPF patients had significantly increased sputum levels of Cd, Cr, Cu and Pb respect to controls. In males, but not in females, sputum levels of Cd, Cr and Cu were significantly higher in IPF cases respect to controls. In addition, Cr and Pb were increased in male patients with IPF compared to male patients with other lung diseases. Regarding Zn, it was found higher with the more serious stage of disease. Moreover, the ratios Cu/Zn, Fe/Mn and Cu/Mn were significantly increased in IPF patients and in non-IPF patients than in control subjects. These data showed clear increases in the concentration of some trace elements in sputum from patients with IPF and patients with other lung-related diseases that may contribute to the injury. The non-invasiveness of the sputum analysis is beneficial for its use as biomarker of trace element status in diseased patients for both the researcher and the clinic.
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Affiliation(s)
- Giovanni Forte
- Department of Environment and Health, Italian National Institute for Health, Rome, Italy
| | - Beatrice Bocca
- Department of Environment and Health, Italian National Institute for Health, Rome, Italy.
| | - Andrea Pisano
- Department of Biomedical Sciences, University of Sassari, Sassari, Italy
| | - Claudia Collu
- Department of Clinical, Surgical & Experimental Sciences, University of Sassari, Sassari, Italy
| | - Cristiano Farace
- Department of Biomedical Sciences, University of Sassari, Sassari, Italy
| | - Angela Sabalic
- Department of Biomedical Sciences, University of Sassari, Sassari, Italy
| | - Marta Senofonte
- Department of Environment and Health, Italian National Institute for Health, Rome, Italy
| | | | | | - Pietro Pirina
- Department of Clinical, Surgical & Experimental Sciences, University of Sassari, Sassari, Italy
| | - Roberto Madeddu
- Department of Biomedical Sciences, University of Sassari, Sassari, Italy
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32
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Nutritional immunity: the impact of metals on lung immune cells and the airway microbiome during chronic respiratory disease. Respir Res 2021; 22:133. [PMID: 33926483 PMCID: PMC8082489 DOI: 10.1186/s12931-021-01722-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 04/15/2021] [Indexed: 12/15/2022] Open
Abstract
Nutritional immunity is the sequestration of bioavailable trace metals such as iron, zinc and copper by the host to limit pathogenicity by invading microorganisms. As one of the most conserved activities of the innate immune system, limiting the availability of free trace metals by cells of the immune system serves not only to conceal these vital nutrients from invading bacteria but also operates to tightly regulate host immune cell responses and function. In the setting of chronic lung disease, the regulation of trace metals by the host is often disrupted, leading to the altered availability of these nutrients to commensal and invading opportunistic pathogenic microbes. Similarly, alterations in the uptake, secretion, turnover and redox activity of these vitally important metals has significant repercussions for immune cell function including the response to and resolution of infection. This review will discuss the intricate role of nutritional immunity in host immune cells of the lung and how changes in this fundamental process as a result of chronic lung disease may alter the airway microbiome, disease progression and the response to infection.
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Kouadri A, Cormenier J, Gemy K, Macari L, Charbonnier P, Richaud P, Michaud-Soret I, Alfaidy N, Benharouga M. Copper-Associated Oxidative Stress Contributes to Cellular Inflammatory Responses in Cystic Fibrosis. Biomedicines 2021; 9:biomedicines9040329. [PMID: 33805052 PMCID: PMC8064106 DOI: 10.3390/biomedicines9040329] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 03/17/2021] [Accepted: 03/19/2021] [Indexed: 12/17/2022] Open
Abstract
Cystic fibrosis (CF) is caused by mutations in the gene encoding the CF Transmembrane Conductance Regulator (CFTR), an apical chloride channel. An early inflammation (EI) in the lung of CF patients occurring in the absence of any bacterial infection has been reported. This EI has been proposed to be associated with oxidative stress (OX-S), generated by deregulations of the oxidant/antioxidant status. Recently, we demonstrated that copper (Cu), an essential trace element, mediates OX-S in bronchial cells. However, the role of this element in the development of CF-EI, in association with OX-S, has never been investigated. Using healthy (16HBE14o-; HBE), CF (CFBE14o-; CFBE), and corrected-wild type CFTR CF (CFBE-wt) bronchial cells, we characterized the inflammation and OX-S profiles in relation to the copper status and CFTR expression and function. We demonstrated that CFBE cells exhibited a CFTR-independent intrinsic inflammation. These cells also exhibited an alteration in mitochondria, UPR (Unfolded Protein Response), catalase, Cu/Zn- and Mn-SOD activities, and an increase in the intracellular content of iron, zinc, and Cu. The increase in Cu concentration was associated with OX-S and inflammatory responses. These data identify cellular Cu as a key factor in the generation of CF-associated OX-S and opens new areas of investigation to better understand CF-associated EI.
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Affiliation(s)
- Amal Kouadri
- Institut National de la Santé et de la Recherche Médicale U1292, Biologie et Biotechnologie Pour la Santé, 38000 Grenoble, France; (A.K.); (J.C.); (K.G.)
- Commissariat à l’Energie Atomique et Aux Energies Alternatives (CEA), 38000 Grenoble, France; (L.M.); (P.C.); (I.M.-S.)
- Université Grenoble Alpes (UGA), 38043 Grenoble, France
| | - Johanna Cormenier
- Institut National de la Santé et de la Recherche Médicale U1292, Biologie et Biotechnologie Pour la Santé, 38000 Grenoble, France; (A.K.); (J.C.); (K.G.)
- Commissariat à l’Energie Atomique et Aux Energies Alternatives (CEA), 38000 Grenoble, France; (L.M.); (P.C.); (I.M.-S.)
- Université Grenoble Alpes (UGA), 38043 Grenoble, France
| | - Kevin Gemy
- Institut National de la Santé et de la Recherche Médicale U1292, Biologie et Biotechnologie Pour la Santé, 38000 Grenoble, France; (A.K.); (J.C.); (K.G.)
- Commissariat à l’Energie Atomique et Aux Energies Alternatives (CEA), 38000 Grenoble, France; (L.M.); (P.C.); (I.M.-S.)
- Université Grenoble Alpes (UGA), 38043 Grenoble, France
| | - Laurence Macari
- Commissariat à l’Energie Atomique et Aux Energies Alternatives (CEA), 38000 Grenoble, France; (L.M.); (P.C.); (I.M.-S.)
- Université Grenoble Alpes (UGA), 38043 Grenoble, France
- Centre National de la Recherche Scientifique (CNRS), LCBM-UMR 5249, 38000 Grenoble, France
| | - Peggy Charbonnier
- Commissariat à l’Energie Atomique et Aux Energies Alternatives (CEA), 38000 Grenoble, France; (L.M.); (P.C.); (I.M.-S.)
- Université Grenoble Alpes (UGA), 38043 Grenoble, France
- Centre National de la Recherche Scientifique (CNRS), LCBM-UMR 5249, 38000 Grenoble, France
| | - Pierre Richaud
- CEA, CNRS, Institut de Biosciences et Biotechnologies d’Aix-Marseille (BIAM), Université Aix-Marseille, UMR 7265, CEA Cadarache, 13108 Saint-Paul-lez Durance, France;
| | - Isabelle Michaud-Soret
- Commissariat à l’Energie Atomique et Aux Energies Alternatives (CEA), 38000 Grenoble, France; (L.M.); (P.C.); (I.M.-S.)
- Université Grenoble Alpes (UGA), 38043 Grenoble, France
- Centre National de la Recherche Scientifique (CNRS), LCBM-UMR 5249, 38000 Grenoble, France
| | - Nadia Alfaidy
- Institut National de la Santé et de la Recherche Médicale U1292, Biologie et Biotechnologie Pour la Santé, 38000 Grenoble, France; (A.K.); (J.C.); (K.G.)
- Commissariat à l’Energie Atomique et Aux Energies Alternatives (CEA), 38000 Grenoble, France; (L.M.); (P.C.); (I.M.-S.)
- Université Grenoble Alpes (UGA), 38043 Grenoble, France
- Correspondance: (N.A.); (M.B.); Tel.: +4-3878-010117 (M.B.); Fax: +4-3878-5058 (M.B.)
| | - Mohamed Benharouga
- Institut National de la Santé et de la Recherche Médicale U1292, Biologie et Biotechnologie Pour la Santé, 38000 Grenoble, France; (A.K.); (J.C.); (K.G.)
- Commissariat à l’Energie Atomique et Aux Energies Alternatives (CEA), 38000 Grenoble, France; (L.M.); (P.C.); (I.M.-S.)
- Université Grenoble Alpes (UGA), 38043 Grenoble, France
- Correspondance: (N.A.); (M.B.); Tel.: +4-3878-010117 (M.B.); Fax: +4-3878-5058 (M.B.)
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Gifford AH, Polineni D, He J, D'Amico JL, Dorman DB, Williams MA, Nymon AB, Balwan A, Budden T, Zuckerman JB. A pilot study of cystic fibrosis exacerbation response phenotypes reveals contrasting serum and sputum iron trends. Sci Rep 2021; 11:4897. [PMID: 33649353 PMCID: PMC7921142 DOI: 10.1038/s41598-021-84041-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Accepted: 02/11/2021] [Indexed: 11/09/2022] Open
Abstract
The cystic fibrosis (CF) community seeks to explain heterogeneous outcomes of pulmonary exacerbation (PEX) treatment. Serum and sputum inflammatory mediators may identify people with CF (PwCF) at risk for suboptimal responses. However, lack of an established association between response phenotypes and these mediators limits clinical application. In this pilot study, we prospectively characterized treatment response phenotypes by assessing health-related quality-of-life (HRQoL) during PEX. We also measured lung function and iron-related biochemical parameters in serum and sputum. We classified subjects as sustained symptom-responders (SRs) or non-sustained symptom-responders (NSRs) based on the absence or presence, respectively, of worsened symptom scores after initial improvement. We used linear mixed models (LMMs) to determine whether trends in lung function, hematologic, serum, and sputum indices of inflammation differed between response cohorts. In 20 PwCF, we identified 10 SRs and 10 NSRs with no significant differences in lung function at PEX onset and treatment durations. SRs had better model-predicted trends in lung function than NSRs during PEX. Non-linear trends in serum and sputum iron levels significantly differed between SRs and NSRs. In adults with cystic fibrosis, PEX treatment response phenotypes may be correlated with distinctive trends in serum and sputum iron concentrations.
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Affiliation(s)
- Alex H Gifford
- Section of Pulmonary Medicine, 5C, Dartmouth-Hitchcock Medical Center, One Medical Center Drive, Lebanon, NH, 03756, USA.
| | - Deepika Polineni
- Division of Pulmonary, Critical Care and Sleep Medicine, University of Kansas Medical Center, 3901 Rainbow Boulevard, Mailstop 3007, Kansas City, KS, 66160, USA.
| | - Jianghua He
- Biostatistics and Data Science, University of Kansas Medical Center, Kansas City, KS, USA
| | - Jessica L D'Amico
- Pulmonary and Critical Care Medicine, Maine Medical Center, Portland, ME, USA
| | - Dana B Dorman
- Section of Pulmonary Medicine, 5C, Dartmouth-Hitchcock Medical Center, One Medical Center Drive, Lebanon, NH, 03756, USA
| | - Molly A Williams
- Section of Pulmonary Medicine, 5C, Dartmouth-Hitchcock Medical Center, One Medical Center Drive, Lebanon, NH, 03756, USA
| | - Amanda B Nymon
- Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA
| | - Akshu Balwan
- Pulmonary and Critical Care Medicine, University of New Mexico, Albuquerque, NM, USA
| | - Theodore Budden
- Division of Pulmonary, Critical Care and Sleep Medicine, University of Kansas Medical Center, 3901 Rainbow Boulevard, Mailstop 3007, Kansas City, KS, 66160, USA
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Portelinha J, Angeles-Boza AM. The Antimicrobial Peptide Gad-1 Clears Pseudomonas aeruginosa Biofilms under Cystic Fibrosis Conditions. Chembiochem 2021; 22:1646-1655. [PMID: 33428273 DOI: 10.1002/cbic.202000816] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 01/09/2021] [Indexed: 02/06/2023]
Abstract
Bacterial infections in cystic fibrosis (CF) patients are an emerging health issue and lead to a premature death. CF is a hereditary disease that creates a thick mucus in the lungs that is prone to bacterial biofilm formation, specifically Pseudomonas aeruginosa biofilms. These biofilms are very difficult to treat because many of them have antibiotic resistance that is worsened by the presence of extracellular DNA (eDNA). eDNA helps to stabilize biofilms and can bind antimicrobial compounds to lessen their effects. The metallo-antimicrobial peptide Gaduscidin-1 (Gad-1) eradicates established P. aeruginosa biofilms through a combination of modes of action that includes nuclease activity that can cleave eDNA in biofilms. In addition, Gad-1 exhibits synergistic activity when used with the antibiotics kanamycin and ciprofloxacin, thus making Gad-1 a new lead compound for the potential treatment of bacterial biofilms in CF patients.
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Affiliation(s)
- Jasmin Portelinha
- Department of Chemistry, University of Connecticut, 55 N. Eagleville Road Storrs, Connecticut, CT 06269, USA
| | - Alfredo M Angeles-Boza
- Department of Chemistry, University of Connecticut, 55 N. Eagleville Road Storrs, Connecticut, CT 06269, USA.,Institute of Material Science, University of Connecticut, 97 N. Eagleville Road Storrs, Connecticut, CT 06269, USA
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Devereux G, Wrolstad D, Bourke SJ, Daines CL, Doe S, Dougherty R, Franco R, Innes A, Kopp BT, Lascano J, Layish D, MacGregor G, Murray L, Peckham D, Lucidi V, Lovie E, Robertson J, Fraser-Pitt DJ, O'Neil DA. Oral cysteamine as an adjunct treatment in cystic fibrosis pulmonary exacerbations: An exploratory randomized clinical trial. PLoS One 2020; 15:e0242945. [PMID: 33370348 PMCID: PMC7769283 DOI: 10.1371/journal.pone.0242945] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 11/03/2020] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Emerging data suggests a possible role for cysteamine as an adjunct treatment for pulmonary exacerbations of cystic fibrosis (CF) that continue to be a major clinical challenge. There are no studies investigating the use of cysteamine in pulmonary exacerbations of CF. This exploratory randomized clinical trial was conducted to answer the question: In future pivotal trials of cysteamine as an adjunct treatment in pulmonary exacerbations of CF, which candidate cysteamine dosing regimens should be tested and which are the most appropriate, clinically meaningful outcome measures to employ as endpoints? METHODS AND FINDINGS Multicentre double-blind randomized clinical trial. Adults experiencing a pulmonary exacerbation of CF being treated with standard care that included aminoglycoside therapy were randomized equally to a concomitant 14-day course of placebo, or one of 5 dosing regimens of cysteamine. Outcomes were recorded on days 0, 7, 14 and 21 and included sputum bacterial load and the patient reported outcome measures (PROMs): Chronic Respiratory Infection Symptom Score (CRISS), the Cystic Fibrosis Questionnaire-Revised (CFQ-R); FEV1, blood leukocyte count, and inflammatory markers. Eighty nine participants in fifteen US and EU centres were randomized, 78 completed the 14-day treatment period. Cysteamine had no significant effect on sputum bacterial load, however technical difficulties limited interpretation. The most consistent findings were for cysteamine 450mg twice daily that had effects additional to that observed with placebo, with improved symptoms, CRISS additional 9.85 points (95% CI 0.02, 19.7) p = 0.05, reduced blood leukocyte count by 2.46x109 /l (95% CI 0.11, 4.80), p = 0.041 and reduced CRP by geometric mean 2.57 nmol/l (95% CI 0.15, 0.99), p = 0.049. CONCLUSION In this exploratory study cysteamine appeared to be safe and well-tolerated. Future pivotal trials investigating the utility of cysteamine in pulmonary exacerbations of CF need to include the cysteamine 450mg doses and CRISS and blood leukocyte count as outcome measures. CLINICAL TRIAL REGISTRATION NCT03000348; www.clinicaltrials.gov.
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Affiliation(s)
- Graham Devereux
- Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Danielle Wrolstad
- Precision for Medicine, Oncology and Rare Disease, Carlsbad, CA, United States of America
| | | | - Cori L. Daines
- Banner University of Arizona Medical Center, Tucson, Arizona, United States of America
| | - Simon Doe
- Royal Victoria Infirmary, Newcastle, United Kingdom
| | - Ryan Dougherty
- San Francisco Critical Care Medical Group California Pacific Medical Center, San Francisco, United States of America
| | - Rose Franco
- The Medical College of Wisconsin/Froedtert Hospital, Milwaukee, Wisconsin, United States of America
| | | | - Benjamin T. Kopp
- Nationwide Children's Hospital, Columbus, OH, United States of America
| | - Jorge Lascano
- University of Florida, Gainesville, Florida, United States of America
| | - Daniel Layish
- Central Florida Pulmonary Group, Orlando, Florida, United States of America
| | | | | | | | - Vincenzina Lucidi
- Ospedale Padiatrico Bambino Gesu Centro Fibrosi Cistica, Rome, Italy
| | - Emma Lovie
- NovaBiotics Ltd, Aberdeen, United Kingdom
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Xie Y, Lu L, Tang XX, Moninger TO, Huang TJ, Stoltz DA, Welsh MJ. Acidic Submucosal Gland pH and Elevated Protein Concentration Produce Abnormal Cystic Fibrosis Mucus. Dev Cell 2020; 54:488-500.e5. [PMID: 32730755 DOI: 10.1016/j.devcel.2020.07.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 06/03/2020] [Accepted: 07/07/2020] [Indexed: 10/24/2022]
Abstract
In response to respiratory insults, airway submucosal glands secrete copious mucus strands to increase mucociliary clearance and protect the lung. However, in cystic fibrosis, stimulating submucosal glands has the opposite effect, disrupting mucociliary transport. In cystic fibrosis (CF) pigs, loss of cystic fibrosis transmembrane conductance regulator (CFTR) anion channels produced submucosal gland mucus that was abnormally acidic with an increased protein concentration. To test whether these variables alter mucus, we produced a microfluidic model of submucosal glands using mucus vesicles from banana slugs. Acidic pH and increased protein concentration decreased mucus gel volume and increased mucus strand elasticity and tensile strength. However, once mucus strands were formed, changing pH or protein concentration largely failed to alter the biophysical properties. Likewise, raising pH or apical perfusion did not improve clearance of mucus strands from CF airways. These findings reveal mechanisms responsible for impaired mucociliary transport in CF and have important implications for potential treatments.
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Affiliation(s)
- Yuliang Xie
- Department of Internal Medicine and Pappajohn Biomedical Institute, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA; Howard Hughes Medical Institute, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Lin Lu
- Department of Internal Medicine and Pappajohn Biomedical Institute, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Xiao Xiao Tang
- Department of Internal Medicine and Pappajohn Biomedical Institute, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA; Howard Hughes Medical Institute, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Thomas O Moninger
- Department of Internal Medicine and Pappajohn Biomedical Institute, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Tony Jun Huang
- Department of Mechanical Engineering and Materials Science, Pratt School of Engineering, Duke University, Durham, NC 27708, USA
| | - David A Stoltz
- Department of Internal Medicine and Pappajohn Biomedical Institute, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA; Department of Molecular Physiology and Biophysics, Roy J and Lucille A Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA; Roy J. Carver Department of Biomedical Engineering, College of Engineering, University of Iowa, Iowa City, IA 52242, USA
| | - Michael J Welsh
- Department of Internal Medicine and Pappajohn Biomedical Institute, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA; Howard Hughes Medical Institute, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA; Department of Molecular Physiology and Biophysics, Roy J and Lucille A Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA.
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38
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King MM, Kayastha BB, Franklin MJ, Patrauchan MA. Calcium Regulation of Bacterial Virulence. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1131:827-855. [PMID: 31646536 DOI: 10.1007/978-3-030-12457-1_33] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Calcium (Ca2+) is a universal signaling ion, whose major informational role shaped the evolution of signaling pathways, enabling cellular communications and responsiveness to both the intracellular and extracellular environments. Elaborate Ca2+ regulatory networks have been well characterized in eukaryotic cells, where Ca2+ regulates a number of essential cellular processes, ranging from cell division, transport and motility, to apoptosis and pathogenesis. However, in bacteria, the knowledge on Ca2+ signaling is still fragmentary. This is complicated by the large variability of environments that bacteria inhabit with diverse levels of Ca2+. Yet another complication arises when bacterial pathogens invade a host and become exposed to different levels of Ca2+ that (1) are tightly regulated by the host, (2) control host defenses including immune responses to bacterial infections, and (3) become impaired during diseases. The invading pathogens evolved to recognize and respond to the host Ca2+, triggering the molecular mechanisms of adhesion, biofilm formation, host cellular damage, and host-defense resistance, processes enabling the development of persistent infections. In this review, we discuss: (1) Ca2+ as a determinant of a host environment for invading bacterial pathogens, (2) the role of Ca2+ in regulating main events of host colonization and bacterial virulence, and (3) the molecular mechanisms of Ca2+ signaling in bacterial pathogens.
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Affiliation(s)
- Michelle M King
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, USA
| | - Biraj B Kayastha
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, USA
| | - Michael J Franklin
- Department of Microbiology and Center for Biofilm Engineering, Montana State University, Bozeman, MT, USA
| | - Marianna A Patrauchan
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, USA.
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39
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Hughes GW, Ridley C, Collins R, Roseman A, Ford R, Thornton DJ. The MUC5B mucin polymer is dominated by repeating structural motifs and its topology is regulated by calcium and pH. Sci Rep 2019; 9:17350. [PMID: 31758042 PMCID: PMC6874590 DOI: 10.1038/s41598-019-53768-0] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 11/01/2019] [Indexed: 01/15/2023] Open
Abstract
The polymeric mucin MUC5B provides the structural and functional framework of respiratory mucus, conferring both viscoelastic and antimicrobial properties onto this vital protective barrier. Whilst it is established that MUC5B forms disulfide-linked linear polymers, how this relates to their packaging in secretory granules, and their molecular form in mucus remain to be fully elucidated. Moreover, the role of the central heavily O-glycosylated mucin domains in MUC5B conformation is incompletely described. Here we have completed a detailed structural analysis on native MUC5B polymers purified from saliva and subsequently investigated how MUC5B conformation is affected by changes in calcium concentration and pH, factors important for mucin intragranular packaging and post-secretory expansion. The results identify that MUC5B has a beaded structure repeating along the polymer axis and suggest that these repeating motifs arise from distinct glycosylation patterns. Moreover, we demonstrate that the conformation of these highly entangled linear polymers is sensitive to calcium concentration and changes in pH. In the presence of calcium (Ca2+, 10 mM) at pH 5.0, MUC5B adopted a compact conformation which was lost either upon removal of calcium with EGTA, or by increasing the pH to 7.4. These results suggest a pathway of mucin collapse to enable intracellular packaging and mechanisms driving mucin expansion following secretion. They also point to the importance of the tight control of calcium and pH during different stages of mucin biosynthesis and secretion, and in the generation of correct mucus barrier properties.
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Affiliation(s)
- Gareth W Hughes
- Wellcome Trust Centre for Cell-Matrix Research, University of Manchester, Manchester Academic Health Sciences Centre, Manchester, M13 9PT, UK.,School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Sciences Centre, Manchester, M13 9PT, UK
| | - Caroline Ridley
- Wellcome Trust Centre for Cell-Matrix Research, University of Manchester, Manchester Academic Health Sciences Centre, Manchester, M13 9PT, UK.,School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Sciences Centre, Manchester, M13 9PT, UK
| | - Richard Collins
- School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Sciences Centre, Manchester, M13 9PT, UK
| | - Alan Roseman
- School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Sciences Centre, Manchester, M13 9PT, UK
| | - Robert Ford
- School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Sciences Centre, Manchester, M13 9PT, UK
| | - David J Thornton
- Wellcome Trust Centre for Cell-Matrix Research, University of Manchester, Manchester Academic Health Sciences Centre, Manchester, M13 9PT, UK. .,Lydia Becker Institute for Immunology and Inflammation, University of Manchester, Manchester Academic Health Sciences Centre, Manchester, M13 9PT, UK. .,School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Sciences Centre, Manchester, M13 9PT, UK.
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40
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Lotlikar SR, Kayastha BB, Vullo D, Khanam SS, Braga RE, Murray AB, McKenna R, Supuran CT, Patrauchan MA. Pseudomonas aeruginosa β-carbonic anhydrase, psCA1, is required for calcium deposition and contributes to virulence. Cell Calcium 2019; 84:102080. [PMID: 31589941 DOI: 10.1016/j.ceca.2019.102080] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 08/16/2019] [Accepted: 09/07/2019] [Indexed: 01/07/2023]
Abstract
Calcification of soft tissue leads to serious diseases and has been associated with bacterial chronic infections. However, the origin and the molecular mechanisms of calcification remain unclear. Here we hypothesized that a human pathogen Pseudomonas aeruginosa deposits extracellular calcium, a process requiring carbonic anhydrases (CAs). Transmission electron microscopy confirmed the formation of 0.1-0.2 μm deposits by P. aeruginosa PAO1 growing at 5 mM CaCl2, and X-ray elemental analysis confirmed they contain calcium. Quantitative analysis of deposited calcium showed that PAO1 deposits 0.35 and 0.75 mM calcium/mg protein when grown at 5 mM and 10 mM CaCl2, correspondingly. Fluorescent microscopy indicated that deposition initiates at the cell surface. We have previously characterized three PAO1 β-class CAs: psCA1, psCA2, and psCA3 that hydrate CO2 to HCO3-, among which psCA1 showed the highest catalytic activity (Lotlikar et. al. 2013). According to immunoblot and RT-qPCR, growth at elevated calcium levels increases the expression of psCA1. Analyses of the deletion mutants lacking one, two or all three psCA genes, determined that psCA1 plays a major role in calcium deposition and contributes to the pathogen's virulence. In-silico modeling of the PAO1 β-class CAs identified four amino acids that differ in psCA1 compared to psCA2, and psCA3 (T59, A61A, A101, and A108), and these differences may play a role in catalytic rate and thus calcium deposition. A series of inhibitors were tested against the recombinant psCA1, among which aminobenzene sulfonamide (ABS) and acetazolamide (AAZ), which inhibited psCA1 catalytic activity with KIs of 19 nM and 37 nM, correspondingly. The addition of ABS and AAZ to growing PAO1 reduced calcium deposition by 41 and 78, respectively. Hence, for the first time, we showed that the β-CA psCA1 in P. aeruginosa contributes to virulence likely by enabling calcium salt deposition, which can be partially controlled by inhibiting its catalytic activity.
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Affiliation(s)
- Shalaka R Lotlikar
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK 74078, USA
| | - Biraj B Kayastha
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK 74078, USA
| | - Daniela Vullo
- Università degli Studi di Firenze, Polo Scientifico, Laboratorio di Chimica Bioinorganica, Rm. 188, Via della Lastruccia 3, 50019 Sesto Fiorentino, Florence, Italy
| | - Sharmily S Khanam
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK 74078, USA
| | - Reygan E Braga
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK 74078, USA
| | - Akilah B Murray
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Robert McKenna
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Claudiu T Supuran
- Università degli Studi di Firenze, Polo Scientifico, Dipartimento Neurofarba, Sezione di Scienze Farmaceutiche, Via Ugo Schiff 6, 50019 Sesto Fiorentino, Florence, Italy
| | - Marianna A Patrauchan
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK 74078, USA.
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Is the Potable Water System an Advantageous Preinfection Niche for Bacteria Colonizing the Cystic Fibrosis Lung? mBio 2019; 10:mBio.00883-19. [PMID: 31164466 PMCID: PMC6550525 DOI: 10.1128/mbio.00883-19] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
People with cystic fibrosis are susceptible to lung infections from a variety of bacteria, a number of which also reside in the potable water system, including Pseudomonas aeruginosa, Stenotrophomonas maltophilia, Achromobacter xylosoxidans, Burkholderia cepacia complex, and nontuberculosis Mycobacteria. Here, I propose chemical and physical aspects of the potable water system along with bacterial lifestyle strategies in this system that may enhance successful colonization of cystic fibrosis lungs by these bacteria, including iron and copper levels, lipids, and low growth rates within low-oxygen biofilms. People with cystic fibrosis are susceptible to lung infections from a variety of bacteria, a number of which also reside in the potable water system, including Pseudomonas aeruginosa, Stenotrophomonas maltophilia, Achromobacter xylosoxidans, Burkholderia cepacia complex, and nontuberculosis Mycobacteria. Here, I propose chemical and physical aspects of the potable water system along with bacterial lifestyle strategies in this system that may enhance successful colonization of cystic fibrosis lungs by these bacteria, including iron and copper levels, lipids, and low growth rates within low-oxygen biofilms.
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Cutone A, Lepanto MS, Rosa L, Scotti MJ, Rossi A, Ranucci S, De Fino I, Bragonzi A, Valenti P, Musci G, Berlutti F. Aerosolized Bovine Lactoferrin Counteracts Infection, Inflammation and Iron Dysbalance in A Cystic Fibrosis Mouse Model of Pseudomonas aeruginosa Chronic Lung Infection. Int J Mol Sci 2019; 20:ijms20092128. [PMID: 31052156 PMCID: PMC6540064 DOI: 10.3390/ijms20092128] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 04/24/2019] [Accepted: 04/25/2019] [Indexed: 02/07/2023] Open
Abstract
Cystic fibrosis (CF) is a genetic disorder affecting several organs including airways. Bacterial infection, inflammation and iron dysbalance play a major role in the chronicity and severity of the lung pathology. The aim of this study was to investigate the effect of lactoferrin (Lf), a multifunctional iron-chelating glycoprotein of innate immunity, in a CF murine model of Pseudomonas aeruginosa chronic lung infection. To induce chronic lung infection, C57BL/6 mice, either cystic fibrosis transmembrane conductance regulator (CFTR)-deficient (Cftrtm1UNCTgN(FABPCFTR)#Jaw) or wild-type (WT), were intra-tracheally inoculated with multidrug-resistant MDR-RP73 P. aeruginosa embedded in agar beads. Treatments with aerosolized bovine Lf (bLf) or saline were started five minutes after infection and repeated daily for six days. Our results demonstrated that aerosolized bLf was effective in significantly reducing both pulmonary bacterial load and infiltrated leukocytes in infected CF mice. Furthermore, for the first time, we showed that bLf reduced pulmonary iron overload, in both WT and CF mice. In particular, at molecular level, a significant decrease of both the iron exporter ferroportin and iron storage ferritin, as well as luminal iron content was observed. Overall, bLf acts as a potent multi-targeting agent able to break the vicious cycle induced by P. aeruginosa, inflammation and iron dysbalance, thus mitigating the severity of CF-related pathology and sequelae.
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Affiliation(s)
- Antimo Cutone
- Department of Biosciences and Territory, University of Molise, 86090 Pesche, Italy.
- Department of Public Health and Infectious Diseases, University of Rome La Sapienza, 00185 Rome, Italy.
| | - Maria Stefania Lepanto
- Department of Public Health and Infectious Diseases, University of Rome La Sapienza, 00185 Rome, Italy.
| | - Luigi Rosa
- Department of Public Health and Infectious Diseases, University of Rome La Sapienza, 00185 Rome, Italy.
| | - Mellani Jinnett Scotti
- Department of Public Health and Infectious Diseases, University of Rome La Sapienza, 00185 Rome, Italy.
| | - Alice Rossi
- Infections and Cystic Fibrosis Unit, Division of Immunology, Transplantation and Infectious Diseases, IRCCS San Raffaele Scientific Institute, 20132 Milano, Italy.
| | - Serena Ranucci
- Infections and Cystic Fibrosis Unit, Division of Immunology, Transplantation and Infectious Diseases, IRCCS San Raffaele Scientific Institute, 20132 Milano, Italy.
| | - Ida De Fino
- Infections and Cystic Fibrosis Unit, Division of Immunology, Transplantation and Infectious Diseases, IRCCS San Raffaele Scientific Institute, 20132 Milano, Italy.
| | - Alessandra Bragonzi
- Infections and Cystic Fibrosis Unit, Division of Immunology, Transplantation and Infectious Diseases, IRCCS San Raffaele Scientific Institute, 20132 Milano, Italy.
| | - Piera Valenti
- Department of Public Health and Infectious Diseases, University of Rome La Sapienza, 00185 Rome, Italy.
| | - Giovanni Musci
- Department of Biosciences and Territory, University of Molise, 86090 Pesche, Italy.
| | - Francesca Berlutti
- Department of Public Health and Infectious Diseases, University of Rome La Sapienza, 00185 Rome, Italy.
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Menacing Mold: Recent Advances in Aspergillus Pathogenesis and Host Defense. J Mol Biol 2019; 431:4229-4246. [PMID: 30954573 DOI: 10.1016/j.jmb.2019.03.027] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 03/21/2019] [Accepted: 03/30/2019] [Indexed: 02/08/2023]
Abstract
The genus Aspergillus is ubiquitous in the environment and contains a number of species, primarily A. fumigatus, that cause mold-associated disease in humans. Humans inhale several hundred to several thousand Aspergillus conidia (i.e., vegetative spores) daily and typically clear these in an asymptomatic manner. In immunocompromised individuals, Aspergillus conidia can germinate into tissue-invasive hyphae, disseminate, and cause invasive aspergillosis. In this review, we first discuss novel concepts in host defense against Aspergillus infections and emphasize new insights in fungal recognition and signaling, innate immune activation, and fungal killing. Second, the review focuses on novel concepts of Aspergillus pathogenesis and highlights emerging knowledge regarding fungal strain heterogeneity, stress responses, and metabolic adaptations on infectious outcomes. Mechanistic insight into the host-pathogen interplay is thus critical to define novel druggable fungal targets and to exploit novel immune-based strategies to improve clinical outcomes associated with aspergillosis in vulnerable patient populations.
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44
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Poole K, Hay T, Gilmour C, Fruci M. The aminoglycoside resistance-promoting AmgRS envelope stress-responsive two-component system in Pseudomonas aeruginosa is zinc-activated and protects cells from zinc-promoted membrane damage. MICROBIOLOGY-SGM 2019; 165:563-571. [PMID: 30835196 DOI: 10.1099/mic.0.000787] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Exposure of wild-type (WT) Pseudomonas aeruginosa PAO1 to ZnCl2 (Zn) yielded a concentration-dependent increase in depolarization of the cytoplasmic membrane (CM), an indication that this metal is membrane-damaging. Consistent with this, Zn activated the AmgRS envelope stress-responsive two-component system (TCS) that was previously shown to be activated by and to protect P. aeruginosa from the membrane-damaging effects of aminoglycoside (AG) antibiotics. A mutant lacking amgR showed enhanced Zn-promoted CM perturbation and was Zn-sensitive, an indication that the TCS protected cells from the CM-damaging effects of this metal. In agreement with this, a mutant carrying an AmgRS-activating amgS mutation was less susceptible to Zn-promoted CM perturbation and more tolerant of elevated levels of Zn than WT. AG activation of AmgRS is known to drive expression of the AG resistance-promoting mexXY multidrug efflux operon, and while Zn similarly induced mexXY expression this was independent of AmgRS and reliant on a second TCS implicated in mexXY regulation, ParRS. MexXY did not, however, contribute to Zn resistance or protection from Zn-promoted CM damage. Despite its activation of AmgRS and induction of mexXY, Zn had a minimal impact on the AG resistance of WT P. aeruginosa although, given that Zn-tolerant AmgRS-activated amgS mutant strains are AG resistant, there is still the prospect of this metal promoting AG resistance development in this organism.
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Affiliation(s)
- Keith Poole
- Department of Biomedical and Molecular Sciences, Botterell Hall, Queen's University, Kingston, Ontario, K7L 3N6, Canada
| | - Thomas Hay
- Department of Biomedical and Molecular Sciences, Botterell Hall, Queen's University, Kingston, Ontario, K7L 3N6, Canada
| | - Christie Gilmour
- Department of Biomedical and Molecular Sciences, Botterell Hall, Queen's University, Kingston, Ontario, K7L 3N6, Canada
| | - Michael Fruci
- Department of Biomedical and Molecular Sciences, Botterell Hall, Queen's University, Kingston, Ontario, K7L 3N6, Canada.,Present address: London Research and Development Centre, Agriculture and Agri-Food, London, Ontario, Canada
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45
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Interaction of gentamicin sulfate with alginate and consequences on the physico-chemical properties of alginate-containing biofilms. Int J Biol Macromol 2018; 121:390-397. [PMID: 30304700 DOI: 10.1016/j.ijbiomac.2018.10.025] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 10/04/2018] [Accepted: 10/05/2018] [Indexed: 12/13/2022]
Abstract
BACKGROUND Alginate is one of the main extracellular polymeric substances (EPS) in biofilms of Cystic Fibrosis (CF) patients suffering from pulmonary infections. Gentamicin sulfate (GS) can strongly bind to alginate resulting in loss of pharmacological activity; however neither the mechanism nor its repercussion is fully understood. In this study, we investigated how GS modifies the alginate macromolecular network and its microenvironment. MATERIAL AND METHODS Alginate gels of two different compositions (either enriched in guluronate units (G) or enriched in mannuronate units (M)) were crosslinked with Ca2+ and exposed to GS at varying times and concentrations. The complexes formed were characterized via turbidimetry, mechanical tests, swelling assay, calorimetry techniques, nuclear magnetic resonance, Ca2+ displacement, macromolecular probe diffusion and pH alteration. RESULTS In presence of GS, the alginate network and its environment undergo a tremendous reorganization in terms of gel density, stiffness, diffusion property, presence and state of the water molecules. We noted that the intensity of those alterations is directly dependent on the polysaccharide motif composition (ratio M/G). CONCLUSION Our results underline the importance of alginate as biofilm component, its pernicious role during antibiotherapy and could represent a potential macromolecular target to improve anti-infectious therapies.
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46
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Price EP, Viberg LT, Kidd TJ, Bell SC, Currie BJ, Sarovich DS. Transcriptomic analysis of longitudinal Burkholderia pseudomallei infecting the cystic fibrosis lung. Microb Genom 2018; 4. [PMID: 29989529 PMCID: PMC6159556 DOI: 10.1099/mgen.0.000194] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The melioidosis bacterium, Burkholderia pseudomallei, is increasingly being recognised as a pathogen in patients with cystic fibrosis (CF). We have recently catalogued genome-wide variation of paired, isogenic B. pseudomallei isolates from seven Australasian CF cases, which were collected between 4 and 55 months apart. Here, we extend this investigation by documenting the transcriptomic changes in B. pseudomallei in five cases. Following growth in an artificial CF sputum medium, four of the five paired isolates exhibited significant differential gene expression (DE) that affected between 32 and 792 genes. The greatest number of DE events was observed between the strains from patient CF9, consistent with the hypermutator status of the latter strain, which is deficient in the DNA mismatch repair protein MutS. Two patient isolates harboured duplications that concomitantly increased expression of the β-lactamase-encoding gene penA, and a 35 kb deletion in another abolished expression of 29 genes. Convergent expression profiles in the chronically-adapted isolates identified two significantly downregulated and 17 significantly upregulated loci, including the resistance-nodulation-division (RND) efflux pump BpeEF-OprC, the quorum-sensing hhqABCDE operon, and a cyanide- and pyocyanin-insensitive cytochrome bd quinol oxidase. These convergent pathoadaptations lead to increased expression of pathways that may suppress competing bacterial and fungal pathogens, and that enhance survival in oxygen-restricted environments, the latter of which may render conventional antibiotics less effective in vivo. Treating chronically adapted B. pseudomallei infections with antibiotics designed to target anaerobic infections, such as the nitroimidazole class of antibiotics, may significantly improve pathogen eradication attempts by exploiting this Achilles heel.
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Affiliation(s)
- Erin P Price
- 1Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Sippy Downs, QLD, Australia.,2Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Northern Territory, Australia
| | - Linda T Viberg
- 2Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Northern Territory, Australia
| | - Timothy J Kidd
- 3Faculty of Medicine, The University of Queensland, Brisbane, QLD, Australia.,4School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD, Australia
| | - Scott C Bell
- 3Faculty of Medicine, The University of Queensland, Brisbane, QLD, Australia.,5QIMR Berghofer Medical Research Institute, Herston, QLD, Australia.,6Department of Thoracic Medicine, The Prince Charles Hospital, Chermside, QLD, Australia
| | - Bart J Currie
- 2Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Northern Territory, Australia.,7Department of Infectious Diseases and Northern Territory Medical Program, Royal Darwin Hospital, Darwin, Northern Territory, Australia
| | - Derek S Sarovich
- 1Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Sippy Downs, QLD, Australia.,2Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Northern Territory, Australia
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47
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Powell LC, Pritchard MF, Ferguson EL, Powell KA, Patel SU, Rye PD, Sakellakou SM, Buurma NJ, Brilliant CD, Copping JM, Menzies GE, Lewis PD, Hill KE, Thomas DW. Targeted disruption of the extracellular polymeric network of Pseudomonas aeruginosa biofilms by alginate oligosaccharides. NPJ Biofilms Microbiomes 2018; 4:13. [PMID: 29977590 PMCID: PMC6026129 DOI: 10.1038/s41522-018-0056-3] [Citation(s) in RCA: 108] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 05/20/2018] [Accepted: 06/06/2018] [Indexed: 11/29/2022] Open
Abstract
Acquisition of a mucoid phenotype by Pseudomonas sp. in the lungs of cystic fibrosis (CF) patients, with subsequent over-production of extracellular polymeric substance (EPS), plays an important role in mediating the persistence of multi-drug resistant (MDR) infections. The ability of a low molecular weight (Mn = 3200 g mol−1) alginate oligomer (OligoG CF-5/20) to modify biofilm structure of mucoid Pseudomonas aeruginosa (NH57388A) was studied in vitro using scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM) with Texas Red (TxRd®)-labelled OligoG and EPS histochemical staining. Structural changes in treated biofilms were quantified using COMSTAT image-analysis software of CLSM z-stack images, and nanoparticle diffusion. Interactions between the oligomers, Ca2+ and DNA were studied using molecular dynamics (MD) simulations, Fourier transform infrared spectroscopy (FTIR) and isothermal titration calorimetry (ITC). Imaging demonstrated that OligoG treatment (≥0.5%) inhibited biofilm formation, revealing a significant reduction in both biomass and biofilm height (P < 0.05). TxRd®-labelled oligomers readily diffused into established (24 h) biofilms. OligoG treatment (≥2%) induced alterations in the EPS of established biofilms; significantly reducing the structural quantities of EPS polysaccharides, and extracellular (e)DNA (P < 0.05) with a corresponding increase in nanoparticle diffusion (P < 0.05) and antibiotic efficacy against established biofilms. ITC demonstrated an absence of rapid complex formation between DNA and OligoG and confirmed the interactions of OligoG with Ca2+ evident in FTIR and MD modelling. The ability of OligoG to diffuse into biofilms, potentiate antibiotic activity, disrupt DNA-Ca2+-DNA bridges and biofilm EPS matrix highlights its potential for the treatment of biofilm-related infections. Small carbohydrate molecules derived from marine algae show potential for inhibiting biofilm formation in multi-drug resistant infections. A research team led by Lydia Powell at Cardiff University, UK, investigated the action of carbohydrates called alginate oligosaccharides, composed of a small number of linked sugar molecules. The oligosaccharides modified and disrupted the structure of cultured biofilms of Pseudomonas aeruginosa, the cause of many serious drug resistant infections. This effect significantly inhibited the formation and maintenance of the biofilm state, which is known to be a crucial factor allowing the bacteria to resist drug treatment. Antibiotics proved more effective following the oligosaccharide intervention. The researchers uncovered key molecular details involved in the ability of the oligosaccharides to diffuse into and disrupt biofilms. The therapeutic potential of these small carbohydrates is currently being investigated in clinical trials.
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Affiliation(s)
- Lydia C Powell
- 1Advanced Therapies Group, Cardiff University School of Dentistry, Heath Park, Cardiff, CF14 4XY UK
| | - Manon F Pritchard
- 1Advanced Therapies Group, Cardiff University School of Dentistry, Heath Park, Cardiff, CF14 4XY UK
| | - Elaine L Ferguson
- 1Advanced Therapies Group, Cardiff University School of Dentistry, Heath Park, Cardiff, CF14 4XY UK
| | - Kate A Powell
- 1Advanced Therapies Group, Cardiff University School of Dentistry, Heath Park, Cardiff, CF14 4XY UK
| | - Shree U Patel
- 1Advanced Therapies Group, Cardiff University School of Dentistry, Heath Park, Cardiff, CF14 4XY UK
| | | | | | - Niklaas J Buurma
- 3Physical Organic Chemistry Centre, School of Chemistry, Cardiff University, Cardiff, UK
| | | | - Jack M Copping
- 4Respiratory Diagnostics Group, Swansea University, Swansea, UK
| | | | - Paul D Lewis
- 4Respiratory Diagnostics Group, Swansea University, Swansea, UK
| | - Katja E Hill
- 1Advanced Therapies Group, Cardiff University School of Dentistry, Heath Park, Cardiff, CF14 4XY UK
| | - David W Thomas
- 1Advanced Therapies Group, Cardiff University School of Dentistry, Heath Park, Cardiff, CF14 4XY UK
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48
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Mixed Communities of Mucoid and Nonmucoid Pseudomonas aeruginosa Exhibit Enhanced Resistance to Host Antimicrobials. mBio 2018; 9:mBio.00275-18. [PMID: 29588399 PMCID: PMC5874919 DOI: 10.1128/mbio.00275-18] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pseudomonas aeruginosa causes chronic pulmonary infections in patients with cystic fibrosis (CF). P. aeruginosa mucoid conversion, defined by overproduction of the exopolysaccharide alginate, correlates with accelerated decline in CF patient lung function. Recalcitrance of the mucoid phenotype to clearance by antibiotics and the immune response is well documented. However, despite advantages conferred by mucoidy, mucoid variants often revert to a nonmucoid phenotype both in vitro and in vivo Mixed populations of mucoid isolates and nonmucoid revertants are recovered from CF lungs, suggesting a selective benefit for coexistence of these variants. In this study, cocultures of mucoid and nonmucoid variants exhibited enhanced resistance to two host antimicrobials: LL-37, a cationic antimicrobial peptide, and hydrogen peroxide (H2O2). Alginate production by mucoid isolates protected nonmucoid variants in consortia from LL-37, as addition of alginate exogenously to nonmucoid variants abrogated LL-37 killing. Conversely, nonmucoid revertants shielded mucoid variants from H2O2 stress via catalase (KatA) production, which was transcriptionally repressed by AlgT and AlgR, central regulators of alginate biosynthesis. Furthermore, extracellular release of KatA by nonmucoid revertants was dependent on lys, encoding an endolysin implicated in autolysis and extracellular DNA (eDNA) release. Overall, these data provide a rationale to study interactions of P. aeruginosa mucoid and nonmucoid variants as contributors to evasion of innate immunity and persistence within the CF lung.IMPORTANCEP. aeruginosa mucoid conversion within lungs of cystic fibrosis (CF) patients is a hallmark of chronic infection and predictive of poor prognosis. The selective benefit of mixed populations of mucoid and nonmucoid variants, often isolated from chronically infected CF patients, has not been explored. Here, we show that mixed-variant communities of P. aeruginosa demonstrate advantages in evasion of innate antimicrobials via production of shared goods: alginate and catalase. These data argue for therapeutically targeting multiple constituents (both mucoid and nonmucoid variants) within diversified P. aeruginosa communities in vivo, as these variants can differentially shield one another from components of the host response.
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49
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Gonzalez MR, Ducret V, Leoni S, Perron K. Pseudomonas aeruginosa zinc homeostasis: Key issues for an opportunistic pathogen. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2018; 1862:722-733. [PMID: 29410128 DOI: 10.1016/j.bbagrm.2018.01.018] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 01/26/2018] [Indexed: 12/13/2022]
Abstract
Zinc is an essential trace element for almost all living organisms. In the opportunistic bacterial pathogen Pseudomonas aeruginosa, zinc has been shown to play an important role in virulence, in colonization of the host organism and has also been shown to be involved in antibiotic resistance. P. aeruginosa possesses numerous systems enabling it to thrive in zinc-depleted conditions as well as high-zinc situations, two environments that are encountered during human infection. These capabilities account for its pathogenic strength. The main aim of this review is to focus on zinc homeostasis in P. aeruginosa and the genetic regulation of the systems involved. The interconnection with virulence, as well as the mechanism of co-regulation between metal and antibiotic resistance, are of prime interest for understanding the molecular mechanisms allowing P. aeruginosa to switch from its existence as a common environmental bacterium to a severe opportunistic pathogen. This article is part of a Special Issue entitled: Dynamic gene expression, edited by Prof. Patrick Viollier.
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Affiliation(s)
- Manuel R Gonzalez
- Microbiology Unit, Department of Botany and Plant Biology, Sciences III, University of Geneva, Geneva, Switzerland
| | - Verena Ducret
- Microbiology Unit, Department of Botany and Plant Biology, Sciences III, University of Geneva, Geneva, Switzerland
| | - Sara Leoni
- Microbiology Unit, Department of Botany and Plant Biology, Sciences III, University of Geneva, Geneva, Switzerland
| | - Karl Perron
- Microbiology Unit, Department of Botany and Plant Biology, Sciences III, University of Geneva, Geneva, Switzerland; School of Pharmaceutical Sciences, University of Geneva and University of Lausanne, Geneva, Switzerland.
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50
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Stewart AC, Bethel CR, VanPelt J, Bergstrom A, Cheng Z, Miller CG, Williams C, Poth R, Morris M, Lahey O, Nix JC, Tierney DL, Page RC, Crowder MW, Bonomo RA, Fast W. Clinical Variants of New Delhi Metallo-β-Lactamase Are Evolving To Overcome Zinc Scarcity. ACS Infect Dis 2017; 3:927-940. [PMID: 28965402 DOI: 10.1021/acsinfecdis.7b00128] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Use and misuse of antibiotics have driven the evolution of serine β-lactamases to better recognize new generations of β-lactam drugs, but the selective pressures driving evolution of metallo-β-lactamases are less clear. Here, we present evidence that New Delhi metallo-β-lactamase (NDM) is evolving to overcome the selective pressure of zinc(II) scarcity. Studies of NDM-1, NDM-4 (M154L), and NDM-12 (M154L, G222D) demonstrate that the point mutant M154L, contained in 50% of clinical NDM variants, selectively enhances resistance to the penam ampicillin at low zinc(II) concentrations relevant to infection sites. Each of the clinical variants is shown to be progressively more thermostable and to bind zinc(II) more tightly than NDM-1, but a selective enhancement of penam turnover at low zinc(II) concentrations indicates that most of the improvement derives from catalysis rather than stability. X-ray crystallography of NDM-4 and NDM-12, as well as bioinorganic spectroscopy of dizinc(II), zinc(II)/cobalt(II), and dicobalt(II) metalloforms probe the mechanism of enhanced resistance and reveal perturbations of the dinuclear metal cluster that underlie improved catalysis. These studies support the proposal that zinc(II) scarcity, rather than changes in antibiotic structure, is driving the evolution of new NDM variants in clinical settings.
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Affiliation(s)
- Alesha C. Stewart
- Division of Chemical
Biology and Medicinal Chemistry, College of Pharmacy, and the LaMontagne
Center for Infectious Disease, University of Texas, Austin, Texas 78712, United States
| | - Christopher R. Bethel
- Research Services, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, Ohio 44106, United States
| | - Jamie VanPelt
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Alex Bergstrom
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Zishuo Cheng
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Callie G. Miller
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Cameron Williams
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Robert Poth
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Matthew Morris
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Olivia Lahey
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Jay C. Nix
- Molecular Biology Consortium, Beamline 4.2.2, Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - David L. Tierney
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Richard C. Page
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Michael W. Crowder
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Robert A. Bonomo
- Research Services, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, Ohio 44106, United States
- Departments
of Medicine, Pharmacology, Molecular Biology and Microbiology, Biochemistry,
Proteomics and Bioinformatics, and the CWRU-Cleveland VAMC Center
for Antimicrobial Resistance and Epidemiology, Cleveland, Ohio 44106, United States
| | - Walter Fast
- Division of Chemical
Biology and Medicinal Chemistry, College of Pharmacy, and the LaMontagne
Center for Infectious Disease, University of Texas, Austin, Texas 78712, United States
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