1
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Jin C, Sengupta A. Microbes in porous environments: from active interactions to emergent feedback. Biophys Rev 2024; 16:173-188. [PMID: 38737203 PMCID: PMC11078916 DOI: 10.1007/s12551-024-01185-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Accepted: 03/27/2024] [Indexed: 05/14/2024] Open
Abstract
Microbes thrive in diverse porous environments-from soil and riverbeds to human lungs and cancer tissues-spanning multiple scales and conditions. Short- to long-term fluctuations in local factors induce spatio-temporal heterogeneities, often leading to physiologically stressful settings. How microbes respond and adapt to such biophysical constraints is an active field of research where considerable insight has been gained over the last decades. With a focus on bacteria, here we review recent advances in self-organization and dispersal in inorganic and organic porous settings, highlighting the role of active interactions and feedback that mediates microbial survival and fitness. We discuss open questions and opportunities for using integrative approaches to advance our understanding of the biophysical strategies which microbes employ at various scales to make porous settings habitable.
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Affiliation(s)
- Chenyu Jin
- Physics of Living Matter Group, Department of Physics and Materials Science, University of Luxembourg, 162 A, Avenue de la Faïencerie, Luxembourg City, L-1511 Luxembourg
| | - Anupam Sengupta
- Physics of Living Matter Group, Department of Physics and Materials Science, University of Luxembourg, 162 A, Avenue de la Faïencerie, Luxembourg City, L-1511 Luxembourg
- Institute for Advanced Studies, University of Luxembourg, 2 Avenue de l’Université, Esch-sur-Alzette, L-4365 Luxembourg
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2
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Parfitt KM, Green AE, Connor TR, Neill DR, Mahenthiralingam E. Identification of two distinct phylogenomic lineages and model strains for the understudied cystic fibrosis lung pathogen Burkholderia multivorans. MICROBIOLOGY (READING, ENGLAND) 2023; 169:001366. [PMID: 37526960 PMCID: PMC10482378 DOI: 10.1099/mic.0.001366] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Accepted: 07/11/2023] [Indexed: 08/02/2023]
Abstract
Burkholderia multivorans is the dominant Burkholderia pathogen recovered from lung infection in people with cystic fibrosis. However, as an understudied pathogen there are knowledge gaps in relation to its population biology, phenotypic traits and useful model strains. A phylogenomic study of B. multivorans was undertaken using a total of 283 genomes, of which 73 were sequenced and 49 phenotypically characterized as part of this study. Average nucleotide identity analysis (ANI) and phylogenetic alignment of core genes demonstrated that the B. multivorans population separated into two distinct evolutionary clades, defined as lineage 1 (n=58 genomes) and lineage 2 (n=221 genomes). To examine the population biology of B. multivorans, a representative subgroup of 77 B. multivorans genomes (28 from the reference databases and the 49 novel short-read genome sequences) were selected based on multilocus sequence typing (MLST), isolation source and phylogenetic placement criteria. Comparative genomics was used to identify B. multivorans lineage-specific genes - ghrB_1 in lineage 1 and glnM_2 in lineage 2 - and diagnostic PCRs targeting them were successfully developed. Phenotypic analysis of 49 representative B. multivorans strains showed considerable inter-strain variance, but the majority of the isolates tested were motile and capable of biofilm formation. A striking absence of B. multivorans protease activity in vitro was observed, but no lineage-specific phenotypic differences were demonstrated. Using phylogenomic and phenotypic criteria, three model B. multivorans CF strains were identified, BCC0084 (lineage 1), BCC1272 (lineage 2a) and BCC0033 lineage 2b, and their complete genome sequences determined. B. multivorans CF strains BCC0033 and BCC0084, and the environmental reference strain, ATCC 17616, were all capable of short-term survival within a murine lung infection model. By mapping the population biology, identifying lineage-specific PCRs and model strains, we provide much needed baseline resources for future studies of B. multivorans.
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Affiliation(s)
- Kasia M. Parfitt
- Cardiff University, Microbiomes, Microbes and Informatics Group, Organisms and Environment Division, School of Biosciences, Cardiff University, CF10 3AX, UK
- Present address: Department of Biology, Big Data Institute, Nuffield Department of Population Health, Li Ka Shing Centre for Health Information and Discovery, Old Road Campus, University of Oxford, Oxford OX3 7LF, UK
| | - Angharad E. Green
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, L69 7BE, UK
| | - Thomas R. Connor
- Cardiff University, Microbiomes, Microbes and Informatics Group, Organisms and Environment Division, School of Biosciences, Cardiff University, CF10 3AX, UK
| | - Daniel R. Neill
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, L69 7BE, UK
- Present address: Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee, DD1 5EH UK, UK
| | - Eshwar Mahenthiralingam
- Cardiff University, Microbiomes, Microbes and Informatics Group, Organisms and Environment Division, School of Biosciences, Cardiff University, CF10 3AX, UK
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3
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The Global Regulator MftR Controls Virulence and Siderophore Production in Burkholderia thailandensis. J Bacteriol 2022; 204:e0023722. [PMID: 36286517 PMCID: PMC9664960 DOI: 10.1128/jb.00237-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacterial pathogens face iron limitation in a host environment. To overcome this challenge, they produce siderophores, small iron-chelating molecules.
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4
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Planet PJ. Adaptation and Evolution of Pathogens in the Cystic Fibrosis Lung. J Pediatric Infect Dis Soc 2022; 11:S23-S31. [PMID: 36069898 PMCID: PMC9451014 DOI: 10.1093/jpids/piac073] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Accepted: 07/11/2022] [Indexed: 02/05/2023]
Abstract
As opposed to acute respiratory infections, the persistent bacterial infections of the lung that characterize cystic fibrosis (CF) provide ample time for bacteria to evolve and adapt. The process of adaptation is recorded in mutations that accumulate over time in the genomes of the infecting bacteria. Some of these mutations lead to obvious phenotypic differences such as antibiotic resistance or the well-known mucoid phenotype of Pseudomonas aeruginosa. Other mutations may be just as important but harder to detect such as increased mutation rates, cell surface changes, and shifts in metabolism and nutrient acquisition. Remarkably, many of the adaptations occur again and again in different patients, signaling that bacteria are adapting to solve specific challenges in the CF respiratory tract. This parallel evolution even extends across distinct bacterial species. This review addresses the bacterial systems that are known to change in long-term CF infections with a special emphasis on cross-species comparisons. Consideration is given to how adaptation may impact health in CF, and the possible evolutionary mechanisms that lead to the repeated parallel adaptations.
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Affiliation(s)
- Paul J Planet
- Corresponding Author: Paul J. Planet, MD, PhD, 3615 Civic Center Blvd, Philadelphia, PA 19104. E-mail:
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5
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Abstract
Bacteria in the Burkholderia cepacia complex (BCC) are significant pathogens for people with cystic fibrosis (CF) and are often extensively antibiotic resistant. Here, we assess the impacts of clinically observed mutations in fixL, which encodes the sensor histidine kinase FixL. FixL along with FixJ compose a two-component system that regulates multiple phenotypes. Mutations in fixL across two species, B. dolosa and B. multivorans, have shown evidence of positive selection during chronic lung infection in CF. Herein, we find that BCC carrying the conserved, ancestral fixL sequence have lower survival in macrophages and in murine pneumonia models than mutants carrying evolved fixL sequences associated with clinical decline in CF patients. In vitro phosphotransfer experiments found that one evolved FixL protein, W439S, has a reduced ability to autophosphorylate and phosphorylate FixJ, while LacZ reporter experiments demonstrate that B. dolosa carrying evolved fixL alleles has reduced fix pathway activity. Interestingly, B. dolosa carrying evolved fixL alleles was less fit in a soil assay than those strains carrying the ancestral allele, demonstrating that increased survival of these variants in macrophages and the murine lung comes at a potential expense in their environmental reservoir. Thus, modulation of the two-component system encoded by fixLJ by point mutations is one mechanism that allows BCC to adapt to the host infection environment.
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6
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Hassan AA, Dos Santos SC, Cooper VS, Sá-Correia I. Comparative Evolutionary Patterns of Burkholderia cenocepacia and B. multivorans During Chronic Co-infection of a Cystic Fibrosis Patient Lung. Front Microbiol 2020; 11:574626. [PMID: 33101250 PMCID: PMC7545829 DOI: 10.3389/fmicb.2020.574626] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Accepted: 08/31/2020] [Indexed: 12/26/2022] Open
Abstract
During chronic respiratory infections of cystic fibrosis (CF) patients, bacteria adaptively evolve in response to the nutritional and immune environment as well as influence other infecting microbes. The present study was designed to gain insights into the genetic mechanisms underlying adaptation and diversification by the two most prevalent pathogenic species of the Burkholderia cepacia complex (Bcc), B. cenocepacia and B. multivorans. Herein, we study the evolution of both of these species during coinfection of a CF patient for 4.4 years using genome sequences of 9 B. multivorans and 11 B. cenocepacia. This co-infection spanned at least 3 years following initial infection by B. multivorans and ultimately ended in the patient's death by cepacia syndrome. Both species acquired several mutations with accumulation rates of 2.08 (B. cenocepacia) and 2.27 (B. multivorans) SNPs/year. Many of the mutated genes are associated with oxidative stress response, transition metal metabolism, defense mechanisms against antibiotics, and other metabolic alterations consistent with the idea that positive selection might be driven by the action of the host immune system, antibiotic therapy and low oxygen and iron concentrations. Two orthologous genes shared by B. cenocepacia and B. multivorans were found to be under strong selection and accumulated mutations associated with lineage diversification. One gene encodes a nucleotide sugar dehydratase involved in lipopolysaccharide O-antigen (OAg) biosynthesis (wbiI). The other gene encodes a putative two-component regulatory sensor kinase protein required to sense and adapt to oxidative- and heavy metal- inducing stresses. This study contributes to understanding of shared and species-specific evolutionary patterns of B. cenocepacia and B. multivorans evolving in the same CF lung environment.
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Affiliation(s)
- A Amir Hassan
- iBB - Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal.,Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
| | - Sandra C Dos Santos
- Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
| | - Vaughn S Cooper
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Isabel Sá-Correia
- iBB - Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal.,Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
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7
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Hassan AA, Coutinho CP, Sá-Correia I. Burkholderia cepacia Complex Species Differ in the Frequency of Variation of the Lipopolysaccharide O-Antigen Expression During Cystic Fibrosis Chronic Respiratory Infection. Front Cell Infect Microbiol 2019; 9:273. [PMID: 31417878 PMCID: PMC6686744 DOI: 10.3389/fcimb.2019.00273] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 07/17/2019] [Indexed: 11/13/2022] Open
Abstract
Burkholderia cepacia complex (Bcc) bacteria can adapt to the lung environment of cystic fibrosis (CF) patients resulting in the emergence of a very difficult to eradicate heterogeneous population leading to chronic infections associated with rapid lung function loss and increased mortality. Among the important phenotypic modifications is the variation of the lipopolysaccharide (LPS) structure at level of the O-antigen (OAg) presence, influencing adherence, colonization and the ability to evade the host defense mechanisms. The present study was performed to understand whether the loss of OAg expression during CF infection can be considered a general phenomenon in different Bcc species favoring its chronicity. In fact, it is still not clear why different Bcc species/strains differ in their ability to persist in the CF lung and pathogenic potential. The systematic two-decade-retrospective-longitudinal-screening conducted covered 357 isolates retrieved from 19 chronically infected patients receiving care at a central hospital in Lisbon. The study involved 21 Bcc strains of six/seven Bcc species/lineages, frequently or rarely isolated from CF patients worldwide. Different strains/clonal variants obtained during infection gave rise to characteristic OAg-banding patterns. The two most prevalent and feared species, B. cenocepacia and B. multivorans, showed a tendency to lose the OAg along chronic infection. B. cenocepacia recA lineage IIIA strains known to lead to particularly destructive infections exhibit the most frequent OAg loss, compared with lineage IIIB. The switch frequency increased with the duration of infection and the level of lung function deterioration. For the first time, it is shown that the rarely found B. cepacia and B. contaminans, whose representation in the cohort of patients examined is abnormally high, keep the OAg even during 10- or 15-year infections. Data from co-infections with different Bcc species reinforced these conclusions. Concerning the two other rarely found species examined, B. stabilis exhibited a stable OAg expression phenotype over the infection period while for the single clone of the more distantly related B. dolosa species, the OAg-chain was absent from the beginning of the 5.5-year infection until the patient dead. This work reinforces the relevance attributed to the OAg-expression switch suggesting marked differences in the various Bcc species.
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Affiliation(s)
- A. Amir Hassan
- iBB - Institute for Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
- Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
| | - Carla P. Coutinho
- Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
| | - Isabel Sá-Correia
- iBB - Institute for Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
- Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
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8
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Cullen L, O'Connor A, McCormack S, Owens RA, Holt GS, Collins C, Callaghan M, Doyle S, Smith D, Schaffer K, Fitzpatrick DA, McClean S. The involvement of the low-oxygen-activated locus of Burkholderia cenocepacia in adaptation during cystic fibrosis infection. Sci Rep 2018; 8:13386. [PMID: 30190507 PMCID: PMC6127331 DOI: 10.1038/s41598-018-31556-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Accepted: 08/20/2018] [Indexed: 12/30/2022] Open
Abstract
Chronic infection with opportunistic pathogens including Burkholderia cepacia complex (Bcc) is a hallmark of cystic fibrosis (CF). We investigated the adaptive mechanisms facilitating chronic lung infection in sequential Bcc isolates from two siblings with CF (P1 and P2), one of whom also experienced intermittent blood-stream infections (P2). We previously showed increased lung cell attachment with colonisation time in both P1 and P2. WGS analysis confirmed that the isolates are closely related. Twelve genes showed three or more mutations, suggesting these were genes under selection. Single nucleotide polymorphisms (SNVs) in 45 regulatory genes were also observed. Proteomic analysis showed that the abundance of 149 proteins increased over 61-months in sputum isolates, and both time- and source-related alterations in protein abundance between the second patient’s isolates. A consistent time-dependent increase in abundance of 19 proteins encoded by a low-oxygen-activated (lxa) locus was observed in both sets of isolates. Attachment was dramatically reduced in a B. cenocepacia K56-2Δlxa-locus deletion mutant, further indicating that it encodes protein(s) involved in host-cell attachment. Time-related changes in virulence in Galleria mellonella or motility were not observed. We conclude that the lxa-locus, associated with anoxic persistence in vitro, plays a role in host-cell attachment and adaptation to chronic colonization in the hypoxic niche of the CF lung.
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Affiliation(s)
- Louise Cullen
- Centre of Microbial Host Interactions, Institute of Technology Tallaght, Dublin, 24, Ireland
| | - Andrew O'Connor
- Centre of Microbial Host Interactions, Institute of Technology Tallaght, Dublin, 24, Ireland.,School of Biomolecular and Biomedical Sciences, University College Dublin, Belfield, Dublin, 4, Ireland
| | - Sarah McCormack
- School of Biomolecular and Biomedical Sciences, University College Dublin, Belfield, Dublin, 4, Ireland
| | - Rebecca A Owens
- Department of Biology, Maynooth University, Co. Kildare, Ireland
| | - Giles S Holt
- Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, England
| | - Cassandra Collins
- Centre of Microbial Host Interactions, Institute of Technology Tallaght, Dublin, 24, Ireland
| | - Máire Callaghan
- Centre of Microbial Host Interactions, Institute of Technology Tallaght, Dublin, 24, Ireland
| | - Sean Doyle
- Department of Biology, Maynooth University, Co. Kildare, Ireland
| | - Darren Smith
- Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, England
| | - Kirsten Schaffer
- Department of Microbiology, St. Vincent's University Hospital, Elm Park, Dublin, Ireland
| | | | - Siobhán McClean
- Centre of Microbial Host Interactions, Institute of Technology Tallaght, Dublin, 24, Ireland. .,School of Biomolecular and Biomedical Sciences, University College Dublin, Belfield, Dublin, 4, Ireland.
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9
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Cullen L, O'Connor A, Drevinek P, Schaffer K, McClean S. Sequential Burkholderia cenocepacia Isolates from Siblings with Cystic Fibrosis Show Increased Lung Cell Attachment. Am J Respir Crit Care Med 2017; 195:832-835. [PMID: 28294652 DOI: 10.1164/rccm.201607-1360le] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Affiliation(s)
- Louise Cullen
- 1 Institute of Technology Tallaght Tallaght, Ireland
| | | | - Pavel Drevinek
- 2 Motol University Hospital Prague, Czech Republic.,3 Charles University Prague, Czech Republic
| | - Kirsten Schaffer
- 4 St. Vincent's University Hospital Elm Park, Dublin, Ireland and
| | - Siobhán McClean
- 1 Institute of Technology Tallaght Tallaght, Ireland.,5 University College Dublin Dublin, Ireland
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10
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Lee AHY, Flibotte S, Sinha S, Paiero A, Ehrlich RL, Balashov S, Ehrlich GD, Zlosnik JEA, Mell JC, Nislow C. Phenotypic diversity and genotypic flexibility of Burkholderia cenocepacia during long-term chronic infection of cystic fibrosis lungs. Genome Res 2017; 27:650-662. [PMID: 28325850 PMCID: PMC5378182 DOI: 10.1101/gr.213363.116] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 02/16/2017] [Indexed: 11/24/2022]
Abstract
Chronic bacterial infections of the lung are the leading cause of morbidity and mortality in cystic fibrosis patients. Tracking bacterial evolution during chronic infections can provide insights into how host selection pressures—including immune responses and therapeutic interventions—shape bacterial genomes. We carried out genomic and phenotypic analyses of 215 serially collected Burkholderia cenocepacia isolates from 16 cystic fibrosis patients, spanning a period of 2–20 yr and a broad range of epidemic lineages. Systematic phenotypic tests identified longitudinal bacterial series that manifested progressive changes in liquid media growth, motility, biofilm formation, and acute insect virulence, but not in mucoidy. The results suggest that distinct lineages follow distinct evolutionary trajectories during lung infection. Pan-genome analysis identified 10,110 homologous gene clusters present only in a subset of strains, including genes restricted to different molecular types. Our phylogenetic analysis based on 2148 orthologous gene clusters from all isolates is consistent with patient-specific clades. This suggests that initial colonization of patients was likely by individual strains, followed by subsequent diversification. Evidence of clonal lineages shared by some patients was observed, suggesting inter-patient transmission. We observed recurrent gene losses in multiple independent longitudinal series, including complete loss of Chromosome III and deletions on other chromosomes. Recurrently observed loss-of-function mutations were associated with decreases in motility and biofilm formation. Together, our study provides the first comprehensive genome-phenome analyses of B. cenocepacia infection in cystic fibrosis lungs and serves as a valuable resource for understanding the genomic and phenotypic underpinnings of bacterial evolution.
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Affiliation(s)
- Amy Huei-Yi Lee
- Department of Microbiology and Immunology.,Department of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Stephane Flibotte
- Department of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada.,Department of Zoology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Sunita Sinha
- Department of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Adrianna Paiero
- Department of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Rachel L Ehrlich
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, USA.,Genomics Core Facility, Clinical and Translational Research Institute, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, USA.,Center for Genomic Sciences, Institute for Molecular Medicine and Infection Diseases, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, USA
| | - Sergey Balashov
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, USA.,Genomics Core Facility, Clinical and Translational Research Institute, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, USA.,Center for Genomic Sciences, Institute for Molecular Medicine and Infection Diseases, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, USA
| | - Garth D Ehrlich
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, USA.,Genomics Core Facility, Clinical and Translational Research Institute, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, USA.,Center for Genomic Sciences, Institute for Molecular Medicine and Infection Diseases, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, USA
| | - James E A Zlosnik
- Centre for Preventing and Understanding Infection in Children, BC Children's Hospital, University of British Columbia, Vancouver, British Columbia V5Z 4H4, Canada
| | - Joshua Chang Mell
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, USA.,Genomics Core Facility, Clinical and Translational Research Institute, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, USA.,Center for Genomic Sciences, Institute for Molecular Medicine and Infection Diseases, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, USA
| | - Corey Nislow
- Department of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
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11
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Schaefers MM, Liao TL, Boisvert NM, Roux D, Yoder-Himes D, Priebe GP. An Oxygen-Sensing Two-Component System in the Burkholderia cepacia Complex Regulates Biofilm, Intracellular Invasion, and Pathogenicity. PLoS Pathog 2017; 13:e1006116. [PMID: 28046077 PMCID: PMC5234846 DOI: 10.1371/journal.ppat.1006116] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Revised: 01/13/2017] [Accepted: 12/09/2016] [Indexed: 12/22/2022] Open
Abstract
Burkholderia dolosa is a member of the Burkholderia cepacia complex (BCC), which is a group of bacteria that cause chronic lung infection in patients with cystic fibrosis (CF) and can be associated with outbreaks carrying high morbidity and mortality. While investigating the genomic diversity of B. dolosa strains collected from an outbreak among CF patients, we previously identified fixL as a gene showing signs of strong positive selection. This gene has homology to fixL of the rhizobial FixL/FixJ two-component system. The goals of this study were to determine the functions of FixLJ and their role in virulence in B. dolosa. We generated a fixLJ deletion mutant and complemented controls in B. dolosa strain AU0158. Using a fixK-lacZ reporter we found that FixLJ was activated in low oxygen in multiple BCC species. In a murine pneumonia model, the B. dolosa fixLJ deletion mutant was cleared faster from the lungs and spleen than wild-type B. dolosa strain AU0158 at 7 days post infection. Interestingly, the fixLJ deletion mutant made more biofilm, albeit with altered structure, but was less motile than strain AU0158. Using RNA-seq with in vitro grown bacteria, we found ~11% of the genome was differentially expressed in the fixLJ deletion mutant relative to strain AU0158. Multiple flagella-associated genes were down-regulated in the fixLJ deletion mutant, so we also evaluated virulence of a fliC deletion mutant, which lacks a flagellum. We saw no difference in the ability of the fliC deletion mutant to persist in the murine model relative to strain AU0158, suggesting factors other than flagella caused the phenotype of decreased persistence. We found the fixLJ deletion mutant to be less invasive in human lung epithelial and macrophage-like cells. In conclusion, B. dolosa fixLJ is a global regulator that controls biofilm formation, motility, intracellular invasion/persistence, and virulence. In people with cystic fibrosis (CF), infection with bacteria in the Burkholderia cepacia complex (BCC) is often associated with clinical deterioration. In a whole-genome sequencing study of the BCC species B. dolosa, we previously identified the fixL gene of the FixL/FixJ two-component system called FixLJ to be under strong positive selective pressure during chronic infection. In this study we show that low oxygen levels activate FixLJ, and that a mutant of B. dolosa in which the fixLJ genes are deleted is less able to persist in the lungs and spread to the spleen in a lung infection model in mice. The fixLJ deletion mutant has defective motility and intracellular survival within epithelial cells and macrophage cell lines. However, a flagella mutant is fully infectious, suggesting that low motility is not responsible for the fixLJ deletion mutant’s inability to persist within the host. Analysis of global RNA expression shows that the fixLJ system regulates many genes, indicating that multiple pathways likely contribute to the low virulence of the fixLJ deletion mutant. In conclusion, B. dolosa FixLJ compose an oxygen sensor that regulates the ability of the bacteria to survive inside host cells.
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Affiliation(s)
- Matthew M. Schaefers
- Division of Critical Care Medicine, Department of Anesthesiology, Perioperative and Pain Medicine, Boston Children’s Hospital, Boston, Massachusetts, United States of America
- Department of Anaesthesia, Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail:
| | - Tiffany L. Liao
- Division of Critical Care Medicine, Department of Anesthesiology, Perioperative and Pain Medicine, Boston Children’s Hospital, Boston, Massachusetts, United States of America
| | - Nicole M. Boisvert
- Division of Critical Care Medicine, Department of Anesthesiology, Perioperative and Pain Medicine, Boston Children’s Hospital, Boston, Massachusetts, United States of America
| | - Damien Roux
- IAME, UMR 1137, INSERM, Université Paris Diderot, Sorbonne Paris Cité, Paris, France; Service de Réanimation médico-chirurgicale, Hôpital Louis Mourier, AP-HP, Colombes, France
| | - Deborah Yoder-Himes
- Department of Biology, University of Louisville, Louisville, Kentucky, United States of America
| | - Gregory P. Priebe
- Division of Critical Care Medicine, Department of Anesthesiology, Perioperative and Pain Medicine, Boston Children’s Hospital, Boston, Massachusetts, United States of America
- Department of Anaesthesia, Harvard Medical School, Boston, Massachusetts, United States of America
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12
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Moreira AS, Lourenço AB, Sá-Correia I. 1H-NMR-Based Endometabolome Profiles of Burkholderia cenocepacia Clonal Variants Retrieved from a Cystic Fibrosis Patient during Chronic Infection. Front Microbiol 2016; 7:2024. [PMID: 28066350 PMCID: PMC5167703 DOI: 10.3389/fmicb.2016.02024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Accepted: 12/02/2016] [Indexed: 12/21/2022] Open
Abstract
During cystic fibrosis (CF) chronic lung infections, bacteria of the Burkholderia cepacia complex (Bcc) are exposed for several years to a stressful and changing environment. These environmental challenges results in genetic changes of the initial infecting strain with the consequent diversification of genotypes and phenotypes. The exploitation of functional and comparative genomic approaches has suggested that such diversification is associated with massive metabolic remodeling but these alterations are poorly understood. In the present work, we have explored a high resolution 1H-NMR-based metabolomic approach coupled to multivariate analysis to compare the endometabolome of three B. cenocepacia clonal variants retrieved from a CF patient from the onset of infection (IST439) until death with cepacia syndrome after 3.5 years (IST4113 and IST4134), to complement former proteomic and transcriptomic analyses. A fourth clonal variant (IST4129) retrieved from the same CF patient when the clinical condition worsened during the last months of life, was also examined since it was found to lack the third replicon. The metabolomic profiles obtained, based on the complete 1H-NMR spectra, highlight the separation of the four clonal variants examined, the most distinct profile corresponding to IST4129. Results indicate a variable content of several amino acids in the different isolates examined and suggest that glycolysis and the glyoxylate shunt are favored in late variants. Moreover, the concentration of two metabolites with demonstrated cellular protective functions against stress, glycine-betaine and trehalose, is different in the different isolates examined. However, no clear correlation could be established between their content and stress tolerance. For example, IST4113, previously found to be the most resistant variant to antimicrobials of different classes, exhibits low levels of trehalose and glycine-betaine but the highest resistance to heat and oxidative stress. Also, IST4129, with a high level of glycine-betaine but lacking the third replicon, previously associated with stress resistance and virulence, exhibits the highest susceptibility to all the stresses tested. Taken together, results from this study provide insights into the metabolic diversification of B. cenocepacia clonal variants during long-term infection of the CF airways.
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Affiliation(s)
- Ana S Moreira
- Department of Bioengineering, Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa (ULISBOA) Lisbon, Portugal
| | - Artur B Lourenço
- Department of Bioengineering, Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa (ULISBOA) Lisbon, Portugal
| | - Isabel Sá-Correia
- Department of Bioengineering, Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa (ULISBOA) Lisbon, Portugal
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Dennis JJ. Burkholderia cenocepacia virulence microevolution in the CF lung: Variations on a theme. Virulence 2016; 8:618-620. [PMID: 27786605 DOI: 10.1080/21505594.2016.1253660] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Affiliation(s)
- Jonathan J Dennis
- a Department of Biological Sciences , Centennial Centre for Interdisciplinary Science, University of Alberta , Edmonton, Alberta , Canada
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14
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Pompilio A, Crocetta V, Ghosh D, Chakrabarti M, Gherardi G, Vitali LA, Fiscarelli E, Di Bonaventura G. Stenotrophomonas maltophilia Phenotypic and Genotypic Diversity during a 10-year Colonization in the Lungs of a Cystic Fibrosis Patient. Front Microbiol 2016; 7:1551. [PMID: 27746770 PMCID: PMC5044509 DOI: 10.3389/fmicb.2016.01551] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 09/15/2016] [Indexed: 11/25/2022] Open
Abstract
The present study was carried out to understand the adaptive strategies developed by Stenotrophomonas maltophilia for chronic colonization of the cystic fibrosis (CF) lung. For this purpose, 13 temporally isolated strains from a single CF patient chronically infected over a 10-year period were systematically characterized for growth rate, biofilm formation, motility, mutation frequencies, antibiotic resistance, and pathogenicity. Pulsed-field gel electrophoresis (PFGE) showed over time the presence of two distinct groups, each consisting of two different pulsotypes. The pattern of evolution followed by S. maltophilia was dependent on pulsotype considered, with strains belonging to pulsotype 1.1 resulting to be the most adapted, being significantly changed in all traits considered. Generally, S. maltophilia adaptation to CF lung leads to increased growth rate and antibiotic resistance, whereas both in vivo and in vitro pathogenicity as well as biofilm formation were decreased. Overall, our results show for the first time that S. maltophilia can successfully adapt to a highly stressful environment such as CF lung by paying a “biological cost,” as suggested by the presence of relevant genotypic and phenotypic heterogeneity within bacterial population. S. maltophilia populations are, therefore, significantly complex and dynamic being able to fluctuate rapidly under changing selective pressures.
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Affiliation(s)
- Arianna Pompilio
- Department of Medical, Oral, and Biotechnological Sciences, "G. d'Annunzio" University of Chieti-PescaraChieti, Italy; Center of Excellence on Aging and Translational Medicine (CeSI-MeT), "G. d'Annunzio" University of Chieti-PescaraChieti, Italy
| | - Valentina Crocetta
- Department of Medical, Oral, and Biotechnological Sciences, "G. d'Annunzio" University of Chieti-PescaraChieti, Italy; Center of Excellence on Aging and Translational Medicine (CeSI-MeT), "G. d'Annunzio" University of Chieti-PescaraChieti, Italy
| | - Dipankar Ghosh
- Special Center for Molecular Medicine, Jawaharlal Nehru University New Delhi, India
| | - Malabika Chakrabarti
- Special Center for Molecular Medicine, Jawaharlal Nehru University New Delhi, India
| | | | | | | | - Giovanni Di Bonaventura
- Department of Medical, Oral, and Biotechnological Sciences, "G. d'Annunzio" University of Chieti-PescaraChieti, Italy; Center of Excellence on Aging and Translational Medicine (CeSI-MeT), "G. d'Annunzio" University of Chieti-PescaraChieti, Italy
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15
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Nunvar J, Kalferstova L, Bloodworth RAM, Kolar M, Degrossi J, Lubovich S, Cardona ST, Drevinek P. Understanding the Pathogenicity of Burkholderia contaminans, an Emerging Pathogen in Cystic Fibrosis. PLoS One 2016; 11:e0160975. [PMID: 27512997 PMCID: PMC4981469 DOI: 10.1371/journal.pone.0160975] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Accepted: 07/27/2016] [Indexed: 12/22/2022] Open
Abstract
Several bacterial species from the Burkholderia cepacia complex (Bcc) are feared opportunistic pathogens that lead to debilitating lung infections with a high risk of developing fatal septicemia in cystic fibrosis (CF) patients. However, the pathogenic potential of other Bcc species is yet unknown. To elucidate clinical relevance of Burkholderia contaminans, a species frequently isolated from CF respiratory samples in Ibero-American countries, we aimed to identify its key virulence factors possibly linked with an unfavorable clinical outcome. We performed a genome-wide comparative analysis of two isolates of B. contaminans ST872 from sputum and blood culture of a female CF patient in Argentina. RNA-seq data showed significant changes in expression for quorum sensing-regulated virulence factors and motility and chemotaxis. Furthermore, we detected expression changes in a recently described low-oxygen-activated (lxa) locus which encodes stress-related proteins, and for two clusters responsible for the biosynthesis of antifungal and hemolytic compounds pyrrolnitrin and occidiofungin. Based on phenotypic assays that confirmed changes in motility and in proteolytic, hemolytic and antifungal activities, we were able to distinguish two phenotypes of B. contaminans that coexisted in the host and entered her bloodstream. Whole genome sequencing revealed that the sputum and bloodstream isolates (each representing a distinct phenotype) differed by over 1,400 mutations as a result of a mismatch repair-deficient hypermutable state of the sputum isolate. The inferred lack of purifying selection against nonsynonymous mutations and the high rate of pseudogenization in the derived isolate indicated limited evolutionary pressure during evolution in the nutrient-rich, stable CF sputum environment. The present study is the first to examine the genomic and transcriptomic differences between longitudinal isolates of B. contaminans. Detected activity of a number of putative virulence factors implies a genuine pathogenic nature of this novel Bcc species.
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Affiliation(s)
- Jaroslav Nunvar
- Department of Medical Microbiology, 2nd Faculty of Medicine, Charles University and Motol University Hospital, Prague, Czech Republic
| | - Lucie Kalferstova
- Department of Medical Microbiology, 2nd Faculty of Medicine, Charles University and Motol University Hospital, Prague, Czech Republic
| | - Ruhi A. M. Bloodworth
- Department of Medical Microbiology & Infectious Disease, University of Manitoba, Winnipeg, Canada
| | - Michal Kolar
- Laboratory of Genomics and Bioinformatics, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Jose Degrossi
- School of Pharmacy and Biochemistry, University of Buenos Aires, Buenos Aires, Argentina
| | - Silvina Lubovich
- Centro Respiratorio Dr. A. Alvarez, Hospital de Niños Ricardo Gutiérrez, Buenos Aires, Argentina
| | - Silvia T. Cardona
- Department of Medical Microbiology & Infectious Disease, University of Manitoba, Winnipeg, Canada
| | - Pavel Drevinek
- Department of Medical Microbiology, 2nd Faculty of Medicine, Charles University and Motol University Hospital, Prague, Czech Republic
- * E-mail:
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16
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Maldonado RF, Sá-Correia I, Valvano MA. Lipopolysaccharide modification in Gram-negative bacteria during chronic infection. FEMS Microbiol Rev 2016; 40:480-93. [PMID: 27075488 PMCID: PMC4931227 DOI: 10.1093/femsre/fuw007] [Citation(s) in RCA: 360] [Impact Index Per Article: 45.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 08/23/2015] [Accepted: 03/10/2016] [Indexed: 12/16/2022] Open
Abstract
The Gram-negative bacterial lipopolysaccharide (LPS) is a major component of the outer membrane that plays a key role in host-pathogen interactions with the innate immune system. During infection, bacteria are exposed to a host environment that is typically dominated by inflammatory cells and soluble factors, including antibiotics, which provide cues about regulation of gene expression. Bacterial adaptive changes including modulation of LPS synthesis and structure are a conserved theme in infections, irrespective of the type or bacteria or the site of infection. In general, these changes result in immune system evasion, persisting inflammation and increased antimicrobial resistance. Here, we review the modifications of LPS structure and biosynthetic pathways that occur upon adaptation of model opportunistic pathogens (Pseudomonas aeruginosa, Burkholderia cepacia complex bacteria, Helicobacter pylori and Salmonella enterica) to chronic infection in respiratory and gastrointestinal sites. We also discuss the molecular mechanisms of these variations and their role in the host-pathogen interaction.
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Affiliation(s)
- Rita F. Maldonado
- Institute for Bioengineering and Biosciences, Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisbon 1049-001, Portugal
| | - Isabel Sá-Correia
- Institute for Bioengineering and Biosciences, Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisbon 1049-001, Portugal
| | - Miguel A. Valvano
- Department of Microbiology and Immunology, University of Western Ontario, London, ON N6A 5C1, Canada
- Centre for Infection and Immunity, Queen's University Belfast, Belfast BT9 7BL, UK
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17
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Kumar B, Cardona ST. Synthetic Cystic Fibrosis Sputum Medium Regulates Flagellar Biosynthesis through the flhF Gene in Burkholderia cenocepacia. Front Cell Infect Microbiol 2016; 6:65. [PMID: 27379216 PMCID: PMC4905959 DOI: 10.3389/fcimb.2016.00065] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 05/30/2016] [Indexed: 12/03/2022] Open
Abstract
Burkholderia cenocepacia belongs to the Burkholderia cepacia complex (Bcc), a group of at least 18 distinct species that establish chronic infections in the lung of people with the genetic disease cystic fibrosis (CF). The sputum of CF patients is rich in amino acids and was previously shown to increase flagellar gene expression in B. cenocepacia. We examined flagellin expression and flagellar morphology of B. cenocepacia grown in synthetic cystic fibrosis sputum medium (SCFM) compared to minimal medium. We found that CF nutritional conditions induce increased motility and flagellin expression. Individual amino acids added at the same concentrations as found in SCFM also increased motility but not flagellin expression, suggesting a chemotactic effect of amino acids. Electron microscopy and flagella staining demonstrated that the increase in flagellin corresponds to a change in the number of flagella per cell. In minimal medium, the ratio of multiple: single: aflagellated cells was 2:3.5:4.5; while under SCFM conditions, the ratio was 7:2:1. We created a deletion mutant, ΔflhF, to study whether this putative GTPase regulates the flagellation pattern of B. cenocepacia K56-2 during growth in CF conditions. The ΔflhF mutant exhibited 80% aflagellated, 14% single and 6% multiple flagellated bacterial subpopulations. Moreover, the ratio of multiple to single flagella in WT and ΔflhF was 3.5 and 0.43, respectively in CF conditions. The observed differences suggest that FlhF positively regulates flagellin expression and the flagellation pattern in B. cenocepacia K56-2 during CF nutritional conditions.
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Affiliation(s)
- Brijesh Kumar
- Department of Microbiology, University of Manitoba Winnipeg, MB, Canada
| | - Silvia T Cardona
- Department of Microbiology, University of ManitobaWinnipeg, MB, Canada; Department of Medical Microbiology and Infectious Diseases, University of ManitobaWinnipeg, MB, Canada
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18
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Zhou H, Wang L, Huang J, Jiang M, Zhang X, Zhang L, Wang Y, Jiang Z, Zhang Z. High EGFR_1 Inside-Out Activated Inflammation-Induced Motility through SLC2A1-CCNB2-HMMR-KIF11-NUSAP1-PRC1-UBE2C. J Cancer 2015; 6:519-24. [PMID: 26000042 PMCID: PMC4439936 DOI: 10.7150/jca.11404] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2014] [Accepted: 02/20/2015] [Indexed: 12/29/2022] Open
Abstract
48 different Pearson mutual-positive-correlation epidermal growth factor receptor (EGFR_1)-activatory molecular feedback, up- and down-stream network was constructed from 171 overlapping of 366 GRNInfer and 223 Pearson under EGFR_1 CC ≥0.25 in high lung adenocarcinoma compared with low human normal adjacent tissues. Our identified EGFR_1 inside-out upstream activated molecular network showed SLC2A1 (solute carrier family 2 (facilitated glucose transporter) member 1), CCNB2 (cyclin B2), HMMR (hyaluronan-mediated motility receptor (RHAMM)), KIF11 (kinesin family member 11), NUSAP1 (nucleolar and spindle associated protein 1), PRC1 (protein regulator of cytokinesis 1), UBE2C (ubiquitin-conjugating enzyme E2C) in high lung adenocarcinoma. EGFR_1 inside-out upstream activated terms network includes intracellular, membrane fraction, cytoplasm, plasma membrane, integral to membrane, basolateral plasma membrane, transmembrane transport, nucleus, cytosol, cell surface; T cell homeostasis, inflammation; microtubule cytoskeleton, embryonic development (sensu Mammalia), cell cycle, mitosis, thymus development, cell division, regulation of cell cycle, Contributed--cellular process--Hs cell cycle KEGG, cytokinesis, M phase, M phase of mitotic cell cycle, estrogen-responsive protein Efp controls cell cycle and breast tumors growth, cell motility, locomotion, locomotory behavior, neoplasm metastasis, spindle pole, spindle microtubule, microtubule motor activity, microtubule-based movement, mitotic spindle organization and biogenesis, mitotic centrosome separation, spindle pole body organization and biogenesis, microtubule-based process, microtubule, cytokinesis after mitosis, mitotic chromosome condensation, establishment of mitotic spindle localization, positive regulation of mitosis, mitotic spindle elongation, spindle organization and biogenesis, positive regulation of exit from mitosis, regulation of cell proliferation, positive regulation of cell proliferation based on integrative GO, KEGG, GenMAPP, BioCarta and disease databases in high lung adenocarcinoma. Therefore, we propose high EGFR_1 inside-out activated inflammation-induced motility through SLC2A1-CCNB2-HMMR-KIF11-NUSAP1-PRC1-UBE2C in lung adenocarcinoma.
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Affiliation(s)
- Huilei Zhou
- 1. Biomedical Center, School of Electronic Engineering, Beijing University of Posts and Telecommunications, Beijing, 100876, China
| | - Lin Wang
- 1. Biomedical Center, School of Electronic Engineering, Beijing University of Posts and Telecommunications, Beijing, 100876, China
| | - Juxiang Huang
- 1. Biomedical Center, School of Electronic Engineering, Beijing University of Posts and Telecommunications, Beijing, 100876, China
| | - Minghu Jiang
- 2. Lab of Computational Linguistics, School of Humanities and Social Sciences, Tsinghua University, Beijing, 100084, China
| | - Xiaoyu Zhang
- 1. Biomedical Center, School of Electronic Engineering, Beijing University of Posts and Telecommunications, Beijing, 100876, China
| | - Liyuan Zhang
- 1. Biomedical Center, School of Electronic Engineering, Beijing University of Posts and Telecommunications, Beijing, 100876, China
| | - Yangming Wang
- 1. Biomedical Center, School of Electronic Engineering, Beijing University of Posts and Telecommunications, Beijing, 100876, China
| | - Zhenfu Jiang
- 1. Biomedical Center, School of Electronic Engineering, Beijing University of Posts and Telecommunications, Beijing, 100876, China
| | - Zhongjie Zhang
- 3. College of information, North China University of Technology, Beijing, 100043, China
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Bacterial Adaptation during Chronic Respiratory Infections. Pathogens 2015; 4:66-89. [PMID: 25738646 PMCID: PMC4384073 DOI: 10.3390/pathogens4010066] [Citation(s) in RCA: 111] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Revised: 02/15/2015] [Accepted: 02/25/2015] [Indexed: 01/22/2023] Open
Abstract
Chronic lung infections are associated with increased morbidity and mortality for individuals with underlying respiratory conditions such as cystic fibrosis (CF) and chronic obstructive pulmonary disease (COPD). The process of chronic colonisation allows pathogens to adapt over time to cope with changing selection pressures, co-infecting species and antimicrobial therapies. These adaptations can occur due to environmental pressures in the lung such as inflammatory responses, hypoxia, nutrient deficiency, osmolarity, low pH and antibiotic therapies. Phenotypic adaptations in bacterial pathogens from acute to chronic infection include, but are not limited to, antibiotic resistance, exopolysaccharide production (mucoidy), loss in motility, formation of small colony variants, increased mutation rate, quorum sensing and altered production of virulence factors associated with chronic infection. The evolution of Pseudomonas aeruginosa during chronic lung infection has been widely studied. More recently, the adaptations that other chronically colonising respiratory pathogens, including Staphylococcus aureus, Burkholderia cepacia complex and Haemophilus influenzae undergo during chronic infection have also been investigated. This review aims to examine the adaptations utilised by different bacterial pathogens to aid in their evolution from acute to chronic pathogens of the immunocompromised lung including CF and COPD.
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Gene expression profiling of Burkholderia cenocepacia at the time of cepacia syndrome: loss of motility as a marker of poor prognosis? J Clin Microbiol 2015; 53:1515-22. [PMID: 25694518 DOI: 10.1128/jcm.03605-14] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Accepted: 02/11/2015] [Indexed: 11/20/2022] Open
Abstract
Cepacia syndrome (CS) is a fatal septic condition that develops in approximately 20% of cystic fibrosis (CF) patients chronically infected with the Burkholderia cepacia complex (Bcc). The most common causative agent is Burkholderia cenocepacia, a clinically dominant Bcc species that contains the globally distributed epidemic strain sequence type 32 (ST32). Using microarrays, we compared the transcriptomes of ST32 isolates from the bloodstream at the time of CS with their sputum counterparts recovered 1 to 2 months prior to the development of CS. Global gene expression profiles of blood isolates revealed greater activities of the virulence genes involved in the type III secretion system, the bacterial exopolysaccharide cepacian, and quorum sensing, while reduced expression was demonstrated for flagellar genes. Furthermore, a nonmotile phenotype (as evaluated by a swimming motility assay) was identified in blood isolates from 6 out of 8 patients with CS; this phenotype was traceable to 24 months prior to the onset of CS. Loss of motility was not observed in any of the 89 ST32 isolates recovered over the course of chronic infection from 17 patients without CS. In conclusion, the gene expression of Bcc bacteria disseminated during CS has been elucidated for the first time. This study demonstrated marked differences at the transcriptome level between isogenic ST32 isolates that are attributable to the stage and site of infection. The finding of a nonmotile B. cenocepacia isolate may serve as a warning sign for the development of CS in the near future.
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