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Kiernan DP, O’Doherty JV, Sweeney T. The Effect of Maternal Probiotic or Synbiotic Supplementation on Sow and Offspring Gastrointestinal Microbiota, Health, and Performance. Animals (Basel) 2023; 13:2996. [PMID: 37835602 PMCID: PMC10571980 DOI: 10.3390/ani13192996] [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: 08/11/2023] [Revised: 09/14/2023] [Accepted: 09/20/2023] [Indexed: 10/15/2023] Open
Abstract
The increasing prevalence of antimicrobial-resistant pathogens has prompted the reduction in antibiotic and antimicrobial use in commercial pig production. This has led to increased research efforts to identify alternative dietary interventions to support the health and development of the pig. The crucial role of the GIT microbiota in animal health and performance is becoming increasingly evident. Hence, promoting an improved GIT microbiota, particularly the pioneer microbiota in the young pig, is a fundamental focus. Recent research has indicated that the sow's GIT microbiota is a significant contributor to the development of the offspring's microbiota. Thus, dietary manipulation of the sow's microbiota with probiotics or synbiotics, before farrowing and during lactation, is a compelling area of exploration. This review aims to identify the potential health benefits of maternal probiotic or synbiotic supplementation to both the sow and her offspring and to explore their possible modes of action. Finally, the results of maternal sow probiotic and synbiotic supplementation studies are collated and summarized. Maternal probiotic or synbiotic supplementation offers an effective strategy to modulate the sow's microbiota and thereby enhance the formation of a health-promoting pioneer microbiota in the offspring. In addition, this strategy can potentially reduce oxidative stress and inflammation in the sow and her offspring, enhance the immune potential of the milk, the immune system development in the offspring, and the sow's feed intake during lactation. Although many studies have used probiotics in the maternal sow diet, the most effective probiotic or probiotic blends remain unclear. To this extent, further direct comparative investigations using different probiotics are warranted to advance the current understanding in this area. Moreover, the number of investigations supplementing synbiotics in the maternal sow diet is limited and is an area where further exploration is warranted.
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Affiliation(s)
- Dillon P. Kiernan
- School of Veterinary Medicine, University College Dublin, D04 C1P1 Dublin, Ireland;
| | - John V. O’Doherty
- School of Agriculture and Food Science, University College Dublin, D04 C1P1 Dublin, Ireland;
| | - Torres Sweeney
- School of Veterinary Medicine, University College Dublin, D04 C1P1 Dublin, Ireland;
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2
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Olaniran OB, Donia A, Adeleke OE, Bokhari H. Prevalence of Type III Secretion System (T3SS) and Biofilm Development in Genetically Heterogeneous Clinical Isolates of Pseudomonas aeruginosa from Nigeria. Curr Microbiol 2023; 80:349. [PMID: 37733140 DOI: 10.1007/s00284-023-03467-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 09/01/2023] [Indexed: 09/22/2023]
Abstract
Pseudomonas aeruginosa infection in seriously ill patients is a major concern due to its ability to form biofilm and secrete effector toxins. There is little information on the prevalence of T3SS effector toxins and biofilm production in clinical isolates of P. aeruginosa from Nigeria. The goal of this study is to evaluate the prevalence of T3SS toxins and biofilm production among isolates from selected tertiary hospitals in Nigeria. This study examined 430 clinical isolates from our previous work, comprising 181 MDR (multidrug-resistant) and 249 non-MDR isolates. Biofilm production and type III secretion toxins were determined using colorimetric microtiter plate assay and polymerase chain reaction, respectively. Carbapenem-resistant isolates were typed using REP-PCR and BOX-PCR. Biofilm production was detected in 386/430 (89.8%) of the isolates. Out of 386 biofilm producers, 167 (43.3%) were multidrug-resistant isolates. PCR identified four T3SS virulence types among 430 isolates, including 78 (18.1%) exoU+/exoS- isolates, 343 (79.8%) exoU-/exoS + isolates, 5 (1.2%) exoU+/exoS + isolates, and 4 (0.9%) exoU-/exoS- isolates. Both REP- and BOX-PCR consist of eight clusters. On the REP-PCR dendrogram, ExoU+/ExoS- isolates majorly occupied cluster IV. Clusters IV, VII, and VIII consist of isolates from wounds on BOX-PCR dendrogram. There was a positive association between strong biofilm production and multidrug resistance in our P. aeruginosa isolates. This study identified multidrug-resistant, biofilm-producing P. aeruginosa strains that secrete cytotoxic effectors which are significant virulence factors in P. aeruginosa. This poses a severe risk to our healthcare system and highlights the importance of continuous surveillance to prevent infectious disease outbreaks.
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Affiliation(s)
- Oluwatoyin B Olaniran
- Department of Pharmaceutical Microbiology, Olabisi Onabanjo University, Ago-Iwoye, Nigeria
- Department of Biosciences, Faculty of Science, COMSATS University Islamabad, Islamabad, Pakistan
| | - Ahmed Donia
- Institute for Water and Wastewater Technology, Durban University of Technology, Durban, South Africa
- Department of Biosciences, Faculty of Science, COMSATS University Islamabad, Islamabad, Pakistan
| | - Olufemi E Adeleke
- Department of Pharmaceutical Microbiology, University of Ibadan, Ibadan, Nigeria
| | - Habib Bokhari
- Department of Biosciences, Faculty of Science, COMSATS University Islamabad, Islamabad, Pakistan.
- Kohsar University Murree, Murree, Pakistan.
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Illek B, Fischer H, Machen TE, Hari G, Clemons KV, Sass G, Ferreira JAG, Stevens DA. Protective role of CFTR during fungal infection of cystic fibrosis bronchial epithelial cells with Aspergillus fumigatus. Front Cell Infect Microbiol 2023; 13:1196581. [PMID: 37680748 PMCID: PMC10482090 DOI: 10.3389/fcimb.2023.1196581] [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: 03/30/2023] [Accepted: 06/19/2023] [Indexed: 09/09/2023] Open
Abstract
Lung infection with the fungus Aspergillus fumigatus (Af) is a common complication in cystic fibrosis (CF) and is associated with loss of pulmonary function. We established a fungal epithelial co-culture model to examine the impact of Af infection on CF bronchial epithelial barrier function using Af strains 10AF and AF293-GFP, and the CFBE41o- cell line homozygous for the F508del mutation with (CF+CFTR) and without (CF) normal CFTR expression. Following exposure of the epithelial surface to Af conidia, formation of germlings (early stages of fungal growth) was detected after 9-12 hours and hyphae (mature fungal growth) after 12-24 hours. During fungal morphogenesis, bronchial epithelial cells showed signs of damage including rounding, and partial detachment after 24 hours. Fluorescently labeled conidia were internalized after 6 hours and more internalized conidia were observed in CF compared to CF+CFTR cells. Infection of the apical surface with 10AF conidia, germlings, or hyphae was performed to determine growth stage-specific effects on tight junction protein zona occludens protein 1 (ZO-1) expression and transepithelial electrical resistance (TER). In response to infection with conidia or germlings, epithelial barrier function degraded time-dependently (based on ZO-1 immunofluorescence and TER) with a delayed onset in CF+CFTR cell monolayers and required viable fungi and apical application. Infection with hyphae caused an earlier onset and faster rate of decline in TER compared to conidia and germlings. Gliotoxin, a major Af virulence factor, caused a rapid decline in TER and induced a transient chloride secretory response in CF+CFTR but not CF cells. Our findings suggest growth and internalization of Af result in deleterious effects on bronchial epithelial barrier function that occurred more rapidly in the absence of CFTR. Bronchial epithelial barrier breakdown was time-dependent and morphotype-specific and mimicked by acute administration of gliotoxin. Our study also suggests a protective role for CFTR by turning on CFTR-dependent chloride transport in response to gliotoxin, a mechanism that will support mucociliary clearance, and could delay the loss of epithelial integrity during fungal development in vivo.
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Affiliation(s)
- Beate Illek
- UCSF Benioff Children's Hospital Oakland, Children's Hospital Oakland Research Institute, Oakland, CA, United States
| | - Horst Fischer
- UCSF Benioff Children's Hospital Oakland, Children's Hospital Oakland Research Institute, Oakland, CA, United States
| | - Terry E. Machen
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, United States
| | - Gopika Hari
- UCSF Benioff Children's Hospital Oakland, Children's Hospital Oakland Research Institute, Oakland, CA, United States
| | - Karl V. Clemons
- California Institute for Medical Research, San Jose, CA, United States
- Division of Infectious Diseases and Geographic Medicine, Stanford University Medical School, Stanford, CA, United States
| | - Gabriele Sass
- California Institute for Medical Research, San Jose, CA, United States
| | - Jose A. G. Ferreira
- California Institute for Medical Research, San Jose, CA, United States
- Division of Infectious Diseases and Geographic Medicine, Stanford University Medical School, Stanford, CA, United States
| | - David A. Stevens
- California Institute for Medical Research, San Jose, CA, United States
- Division of Infectious Diseases and Geographic Medicine, Stanford University Medical School, Stanford, CA, United States
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4
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Morreale DP, Porsch EA, Kern BK, St Geme JW, Planet PJ. Acquisition, co-option, and duplication of the rtx toxin system and the emergence of virulence in Kingella. Nat Commun 2023; 14:4281. [PMID: 37460464 DOI: 10.1038/s41467-023-39939-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Accepted: 07/04/2023] [Indexed: 07/20/2023] Open
Abstract
The bacterial genus Kingella includes two pathogenic species, namely Kingella kingae and Kingella negevensis, as well as strictly commensal species. Both K. kingae and K. negevensis secrete a toxin called RtxA that is absent in the commensal species. Here we present a phylogenomic study of the genus Kingella, including new genomic sequences for 88 clinical isolates, genotyping of another 131 global isolates, and analysis of 52 available genomes. The phylogenetic evidence supports that the toxin-encoding operon rtxCA was acquired by a common ancestor of the pathogenic Kingella species, and that a preexisting type-I secretion system was co-opted for toxin export. Subsequent genomic reorganization distributed the toxin machinery across two loci, with 30-35% of K. kingae strains containing two copies of the rtxA toxin gene. The rtxA duplication is largely clonal and is associated with invasive disease. Assays with isogenic strains show that a single copy of rtxA is associated with reduced cytotoxicity in vitro. Thus, our study identifies key steps in the evolutionary transition from commensal to pathogen, including horizontal gene transfer, co-option of an existing secretion system, and gene duplication.
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Affiliation(s)
- Daniel P Morreale
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Division of Infectious Diseases, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Eric A Porsch
- Division of Infectious Diseases, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Brad K Kern
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Division of Infectious Diseases, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Joseph W St Geme
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Division of Infectious Diseases, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Paul J Planet
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
- Division of Infectious Diseases, Children's Hospital of Philadelphia, Philadelphia, PA, USA.
- Comparative Genomics, American Museum of Natural History, New York, NY, USA.
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Evaluating Bacterial Pathogenesis Using a Model of Human Airway Organoids Infected with Pseudomonas aeruginosa Biofilms. Microbiol Spectr 2022; 10:e0240822. [PMID: 36301094 PMCID: PMC9769610 DOI: 10.1128/spectrum.02408-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Pseudomonas aeruginosa is one of the leading invasive agents of human pulmonary infection, especially in patients with compromised immunity. Prior studies have used various in vitro models to establish P. aeruginosa infection and to analyze transcriptomic profiles of either the host or pathogen, and yet how much those works are relevant to the genuine human airway still raises doubts. In this study, we cultured and differentiated human airway organoids (HAOs) that recapitulate, to a large extent, the histological and physiological features of the native human mucociliary epithelium. HAOs were then employed as a host model to monitor P. aeruginosa biofilm development. Through dual-species transcriptome sequencing (RNA-seq) analyses, we found that quorum sensing (QS) and several associated protein secretion systems were significantly upregulated in HAO-associated bacteria. Cocultures of HAOs and QS-defective mutants further validated the role of QS in the maintenance of a robust biofilm and disruption of host tissue. Simultaneously, the expression magnitude of multiple inflammation-associated signaling pathways was higher in the QS mutant-infected HAOs, suggesting that QS promotes immune evasion at the transcriptional level. Altogether, modeling infection of HAOs by P. aeruginosa captured several crucial facets in host responses and bacterial pathogenesis, with QS being the most dominant virulence pathway showing profound effects on both bacterial biofilm and host immune responses. Our results revealed that HAOs are an optimal model for studying the interaction between the airway epithelium and bacterial pathogens. IMPORTANCE Human airway organoids (HAOs) are an organotypic model of human airway mucociliary epithelium. The HAOs can closely resemble their origin organ in terms of epithelium architecture and physiological function. Accumulating studies have revealed the great values of the HAO cultures in host-pathogen interaction research. In this study, HAOs were used as a host model to grow Pseudomonas aeruginosa biofilm, which is one of the most common pathogens found in pulmonary infection cases. Dual transcriptome sequencing (RNA-seq) analyses showed that the cocultures have changed the gene expression pattern of both sides significantly and simultaneously. Bacterial quorum sensing (QS), the most upregulated pathway, contributed greatly to biofilm formation, disruption of barrier function, and subversion of host immune responses. Our study therefore provides a global insight into the transcriptomic responses of both P. aeruginosa and human airway epithelium.
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6
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Airway Epithelial Cell Junctions as Targets for Pathogens and Antimicrobial Therapy. Pharmaceutics 2022; 14:pharmaceutics14122619. [PMID: 36559113 PMCID: PMC9786141 DOI: 10.3390/pharmaceutics14122619] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 11/22/2022] [Accepted: 11/24/2022] [Indexed: 11/29/2022] Open
Abstract
Intercellular contacts between epithelial cells are established and maintained by the apical junctional complexes (AJCs). AJCs conserve cell polarity and build epithelial barriers to pathogens, inhaled allergens, and environmental particles in the respiratory tract. AJCs consist of tight junctions (TJs) and adherens junctions (AJs), which play a key role in maintaining the integrity of the airway barrier. Emerging evidence has shown that different microorganisms cause airway barrier dysfunction by targeting TJ and AJ proteins. This review discusses the pathophysiologic mechanisms by which several microorganisms (bacteria and viruses) lead to the disruption of AJCs in airway epithelial cells. We present recent progress in understanding signaling pathways involved in the formation and regulation of cell junctions. We also summarize the potential chemical inhibitors and pharmacological approaches to restore the integrity of the airway epithelial barrier. Understanding the AJCs-pathogen interactions and mechanisms by which microorganisms target the AJC and impair barrier function may further help design therapeutic innovations to treat these infections.
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7
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Lenárt S, Lenárt P, Knopfová L, Kotasová H, Pelková V, Sedláková V, Vacek O, Pokludová J, Čan V, Šmarda J, Souček K, Hampl A, Beneš P. TACSTD2 upregulation is an early reaction to lung infection. Sci Rep 2022; 12:9583. [PMID: 35688908 PMCID: PMC9185727 DOI: 10.1038/s41598-022-13637-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 05/18/2022] [Indexed: 11/16/2022] Open
Abstract
TACSTD2 encodes a transmembrane glycoprotein Trop2 commonly overexpressed in carcinomas. While the Trop2 protein was discovered already in 1981 and first antibody–drug conjugate targeting Trop2 were recently approved for cancer therapy, the physiological role of Trop2 is still not fully understood. In this article, we show that TACSTD2/Trop2 expression is evolutionarily conserved in lungs of various vertebrates. By analysis of publicly available transcriptomic data we demonstrate that TACSTD2 level consistently increases in lungs infected with miscellaneous, but mainly viral pathogens. Single cell and subpopulation based transcriptomic data revealed that the major source of TACSTD2 transcript are lung epithelial cells and their progenitors and that TACSTD2 is induced directly in lung epithelial cells following infection. Increase in TACSTD2 expression may represent a mechanism to maintain/restore epithelial barrier function and contribute to regeneration process in infected/damaged lungs.
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Affiliation(s)
- Sára Lenárt
- Department of Experimental Biology, Faculty of Science, Masaryk University, Kamenice 5, Brno, 62500, Czech Republic
| | - Peter Lenárt
- Department of Experimental Biology, Faculty of Science, Masaryk University, Kamenice 5, Brno, 62500, Czech Republic.,Faculty of Science, Research Centre for Toxic Compounds in the Environment, Masaryk University, Brno, Czech Republic.,Institute of Cell Biology, University of Bern, Bern, Switzerland
| | - Lucia Knopfová
- Department of Experimental Biology, Faculty of Science, Masaryk University, Kamenice 5, Brno, 62500, Czech Republic.,International Clinical Research Center, St. Anne's University Hospital, Brno, Czech Republic
| | - Hana Kotasová
- International Clinical Research Center, St. Anne's University Hospital, Brno, Czech Republic.,Department of Histology and Embryology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Vendula Pelková
- Department of Histology and Embryology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Veronika Sedláková
- Department of Histology and Embryology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Ondřej Vacek
- Department of Experimental Biology, Faculty of Science, Masaryk University, Kamenice 5, Brno, 62500, Czech Republic.,International Clinical Research Center, St. Anne's University Hospital, Brno, Czech Republic.,Department of Cytokinetics, Institute of Biophysics of the Czech Academy of Sciences, Brno, Czech Republic
| | - Jana Pokludová
- Department of Experimental Biology, Faculty of Science, Masaryk University, Kamenice 5, Brno, 62500, Czech Republic
| | - Vladimír Čan
- Department of Surgery, University Hospital Brno, Brno, Czech Republic
| | - Jan Šmarda
- Department of Experimental Biology, Faculty of Science, Masaryk University, Kamenice 5, Brno, 62500, Czech Republic
| | - Karel Souček
- Department of Experimental Biology, Faculty of Science, Masaryk University, Kamenice 5, Brno, 62500, Czech Republic.,International Clinical Research Center, St. Anne's University Hospital, Brno, Czech Republic.,Department of Cytokinetics, Institute of Biophysics of the Czech Academy of Sciences, Brno, Czech Republic
| | - Aleš Hampl
- International Clinical Research Center, St. Anne's University Hospital, Brno, Czech Republic.,Department of Histology and Embryology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Petr Beneš
- Department of Experimental Biology, Faculty of Science, Masaryk University, Kamenice 5, Brno, 62500, Czech Republic. .,International Clinical Research Center, St. Anne's University Hospital, Brno, Czech Republic.
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8
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Shen E, Yang J, Tsuei KSC. The role of Type III secretion system in the pathogenesis of Pseudomonas aeruginosa microbial keratitis. Tzu Chi Med J 2022; 34:8-14. [PMID: 35233350 PMCID: PMC8830546 DOI: 10.4103/tcmj.tcmj_47_21] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 03/11/2021] [Accepted: 03/17/2021] [Indexed: 11/22/2022] Open
Abstract
Pseudomonas aeruginosa is the most commonly isolated Gram-negative pathogen causing sight-threatening microbial keratitis (MK). Contact lens wear is the most significant risk factor associated with pseudomonal MK. Understanding the pathogenesis of MK due to P. aeruginosa and its interactions with contact lenses is crucial in preventing these often rapidly progressive and highly antibiotic-resistant infections. Bacterial virulence factor Type III secretion system (T3SS) has significant interplays between contact lens material, antibiotic sensitivity, disinfectant selectivity, and bacterial cell invasion. Depending on the T3SS exotoxins produced, P. aeruginosa strains are divided into cytotoxic or invasive strains. Cytotoxic strains are relatively resistant to commercial disinfectants, while invasive strains are more antibiotic resistant. Therefore, contact lens wearers are more predisposed to cytotoxic P. aeruginosa infections, and patients with trauma or previous surgery are more prone to infection by invasive strains. Previous studies with mutant P. aeruginosa strains unable to produce T3SS exotoxins were more susceptible to disinfectants and less able to adhere to soft contact lenses, indicating an essential role of T3SS in bacterial virulence. Invasion of P. aeruginosa intracellularly was found to be associated with control of scaffold protein IQ-domain GTPase-activating protein 1 (IQGAP1) and human corneal epithelial cell tight junctions. Knockdown of IQGAP1 strengthened tight junctions that prevented intracellular survival of invasive P. aeruginosa strains and enhanced corneal epithelial cell survival. These novel findings of the vital role of T3SS in the pathogenesis of pseudomonal MKs will provide new guidelines in both prevention and treatment of this common eye-blinding infection.
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Molecular Mechanisms Involved in Pseudomonas aeruginosa Bacteremia. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1386:325-345. [DOI: 10.1007/978-3-031-08491-1_12] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2023]
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10
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Wagener BM, Hu R, Wu S, Pittet JF, Ding Q, Che P. The Role of Pseudomonas aeruginosa Virulence Factors in Cytoskeletal Dysregulation and Lung Barrier Dysfunction. Toxins (Basel) 2021; 13:776. [PMID: 34822560 PMCID: PMC8625199 DOI: 10.3390/toxins13110776] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 10/24/2021] [Accepted: 10/28/2021] [Indexed: 12/19/2022] Open
Abstract
Pseudomonas (P.) aeruginosa is an opportunistic pathogen that causes serious infections and hospital-acquired pneumonia in immunocompromised patients. P. aeruginosa accounts for up to 20% of all cases of hospital-acquired pneumonia, with an attributable mortality rate of ~30-40%. The poor clinical outcome of P. aeruginosa-induced pneumonia is ascribed to its ability to disrupt lung barrier integrity, leading to the development of lung edema and bacteremia. Airway epithelial and endothelial cells are important architecture blocks that protect the lung from invading pathogens. P. aeruginosa produces a number of virulence factors that can modulate barrier function, directly or indirectly, through exploiting cytoskeleton networks and intercellular junctional complexes in eukaryotic cells. This review summarizes the current knowledge on P. aeruginosa virulence factors, their effects on the regulation of the cytoskeletal network and associated components, and molecular mechanisms regulating barrier function in airway epithelial and endothelial cells. A better understanding of these processes will help to lay the foundation for new therapeutic approaches against P. aeruginosa-induced pneumonia.
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Affiliation(s)
- Brant M. Wagener
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA; (B.M.W.); (R.H.); (S.W.); (J.-F.P.); (Q.D.)
- Division of Molecular and Translational Biomedicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
- Division of Critical Care Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
- Center for Free Radical Biology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Ruihan Hu
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA; (B.M.W.); (R.H.); (S.W.); (J.-F.P.); (Q.D.)
- Division of Molecular and Translational Biomedicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
- Department of Internal Medicine, Guiqian International General Hospital, Guiyang 550024, China
| | - Songwei Wu
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA; (B.M.W.); (R.H.); (S.W.); (J.-F.P.); (Q.D.)
- Division of Molecular and Translational Biomedicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Jean-Francois Pittet
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA; (B.M.W.); (R.H.); (S.W.); (J.-F.P.); (Q.D.)
- Division of Molecular and Translational Biomedicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
- Division of Critical Care Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Qiang Ding
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA; (B.M.W.); (R.H.); (S.W.); (J.-F.P.); (Q.D.)
- Division of Molecular and Translational Biomedicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Pulin Che
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA; (B.M.W.); (R.H.); (S.W.); (J.-F.P.); (Q.D.)
- Division of Molecular and Translational Biomedicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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11
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Xu Y, Jin D, Ye H, Liang Y. A rare case of Pseudomonas aeruginosa bacteremia in a newborn with 58 perforations in the small intestine. BMC Pediatr 2021; 21:9. [PMID: 33402134 PMCID: PMC7784015 DOI: 10.1186/s12887-020-02466-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 12/11/2020] [Indexed: 11/29/2022] Open
Abstract
Background Community-acquired infections of Pseudomonas aeruginosa (P. aeruginosa) occur very rarely. Case presentation P. aeruginos was detected in cultures of venous blood and peritoneal exudate of a newborn with 58 perforations in the small intestine. Intravenous administration of imipenem cilastratin sodium and emergency abdominal surgery were performed. The patient fully recovered and was discharged 17 days after the operation. Conclusions Mild symptoms of systemic infections in newborns may delay the diagnosis. Early detection and timely treatment are the key to improved prognosis.
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Affiliation(s)
- Yuanyuan Xu
- Department of Pediatric Intensive Care Unit, Anhui Provincial Children's Hospital, Hefei, China
| | - Danqun Jin
- Department of Pediatric Intensive Care Unit, Anhui Provincial Children's Hospital, Hefei, China.
| | - Huan Ye
- Department of Neurosurgery, Anhui Provincial Children's Hospital, Hefei, China
| | - Youfeng Liang
- Department of Cardiology, First Affiliated Hospital of Anhui Medical University, Hefei, China
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12
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Bronchial Epithelial Tet2 Maintains Epithelial Integrity during Acute Pseudomonas aeruginosa Pneumonia. Infect Immun 2020; 89:IAI.00603-20. [PMID: 33046509 DOI: 10.1128/iai.00603-20] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 10/05/2020] [Indexed: 12/23/2022] Open
Abstract
Respiratory epithelial cells are important for pulmonary innate immune responses during Pseudomonas aeruginosa infection. Tet methylcytosine dioxygenase 2 (Tet2) has been implicated in the regulation of host defense by myeloid and lymphoid cells, but whether Tet2 also contributes to epithelial responses during pneumonia is unknown. The aim of this study was to investigate the role of bronchial epithelial Tet2 in acute pneumonia caused by P. aeruginosa To this end, we crossed mice with Tet2 flanked by two Lox-P sites (Tet2fl/fl mice) with mice expressing Cre recombinase under the bronchial epithelial cell-specific Cc10 promoter (Cc10Cre mice) to generate bronchial epithelial cell-specific Tet2-deficient (Tet2fl/fl Cc10Cre ) mice. Six hours after infection with P. aeruginosa, Tet2fl/fl Cc10Cre and wild-type mice had similar bacterial loads in bronchoalveolar lavage fluid (BALF). At this time point, Tet2fl/fl Cc10Cre mice displayed reduced mRNA levels of the chemokines Cxcl1, Cxcl2, and Ccl20 in bronchial brushes. However, Cxcl1, Cxcl2, and Ccl20 protein levels and leukocyte recruitment in BALF were not different between groups. Tet2fl/fl Cc10Cre mice had increased protein levels in BALF after infection, indicating a disturbed epithelial barrier function, which was corroborated by reduced mRNA expression of tight junction protein 1 and occludin in bronchial brushes. Differences detected between Tet2fl/fl Cc10Cre and wild-type mice were no longer present at 24 h after infection. These results suggest that bronchial epithelial Tet2 contributes to maintaining epithelial integrity by enhancing intracellular connections between epithelial cells during the early phase of P. aeruginosa pneumonia.
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13
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Riquelme SA, Prince A. Airway immunometabolites fuel Pseudomonas aeruginosa infection. Respir Res 2020; 21:326. [PMID: 33302964 PMCID: PMC7731785 DOI: 10.1186/s12931-020-01591-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Accepted: 11/30/2020] [Indexed: 02/07/2023] Open
Abstract
Pulmonary infections are associated with a brisk inflammatory reaction to bacterial surface components. Lipopolysaccharides (LPS) trigger macrophage activation and release of mitochondrial metabolites that control the intensity of the immune response. Whereas succinate induces oxidative stress (ROS), HIF1α stabilization, glycolysis and IL-1β release, itaconate suppresses inflammation by inhibiting succinate oxidation, glycolytic flux and promoting anti-oxidant Nrf2-HO-1 functions. P. aeruginosa is a major pathogen associated with acute and chronic lung infection. Although both secreted toxins, LPS and proteases are key factors to establish acute P. aeruginosa pneumonia, lack of these components in chronic P. aeruginosa isolates suggest these organisms exploit other mechanisms to adapt and persist in the lung. Upon inhalation, P. aeruginosa strains trigger airway macrophage reprograming and bacterial variants obtained from acutely and chronically infected subjects exhibit metabolic adaptation consistent with succinate and itaconate assimilation; namely, high expression of extracellular polysaccharides (EPS), reduced lptD-LPS function, increased glyoxylate shunt (GS) activity and substantial biofilm production. In this review we discuss recent findings illustrating how P. aeruginosa induces and adapts to macrophage metabolites in the human lung, and that catabolism of succinate and itaconate contribute to their formidable abilities to tolerate oxidative stress, phagocytosis and immune clearance.
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Affiliation(s)
| | - Alice Prince
- Department of Pediatrics, Columbia University, New York, NY, 10032, USA.
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14
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Paracellular Pathway-Mediated Mycoplasma hyopneumoniae Migration across Porcine Airway Epithelial Barrier under Air-Liquid Interface Conditions. Infect Immun 2020; 88:IAI.00470-20. [PMID: 32747599 DOI: 10.1128/iai.00470-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Accepted: 07/29/2020] [Indexed: 02/05/2023] Open
Abstract
Mycoplasma hyopneumoniae is an important respiratory pathogen of pigs that causes persistent and secondary infections. However, the mechanisms by which this occurs are unclear. In this study, we established air-liquid interface culture systems for pig bronchial epithelial cells (ALI-PBECs) that were comparable to the conditions in the native bronchus in vivo We used this ALI-PBECs model to study the infection and migration characteristics of M. hyopneumoniae in vitro Based on the results, we confirmed that M. hyopneumoniae was able to adhere to ALI-PBECs and disrupt mucociliary function. Importantly, M. hyopneumoniae could migrate to the basolateral chamber through the paracellular route but not the transcellular pathway, and this was achieved by reversibly disrupting tight junctions (TJs) and increasing the permeability and damaging the integrity of the epithelial barrier. We examined the migration ability of M. hyopneumoniae using an ALI-PBECs model for the first time. The disruption of the epithelial barrier allowed M. hyopneumoniae to migrate to the basolateral chamber through the paracellular route, which may be related to immune evasion, extrapulmonary dissemination, and persistent infection of M. hyopneumoniae.
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15
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Hasannejad-Bibalan M, Jafari A, Sabati H, Goswami R, Jafaryparvar Z, Sedaghat F, Sedigh Ebrahim-Saraie H. Risk of type III secretion systems in burn patients with Pseudomonas aeruginosa wound infection: A systematic review and meta-analysis. Burns 2020; 47:538-544. [PMID: 32532479 DOI: 10.1016/j.burns.2020.04.024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2019] [Revised: 03/17/2020] [Accepted: 04/23/2020] [Indexed: 12/21/2022]
Abstract
PURPOSE The pathogenesis of Pseudomonas aeruginosa is multifactorial and attributed to the production of several cell-associated and extracellular virulence factors including those implicated in adherence, iron uptake, exoenzymes (Exo) and exotoxins. The present study aimed to determine the prevalence of type III secretion systems (T3SS) effectors in Iranian burn patients with P. aeruginosa wound infection. METHODS A systematic search was conducted to identify papers published by Iranian authors in the Web of Science, PubMed, Scopus, Embase, and Google Scholar electronic databases during the period of January, 2000 to December, 2018. Publications which met our inclusion criteria were selected for data extraction and analysis by Comprehensive Meta-Analysis Software. The inclusion criteria were articles that include burn patients with a wound infection caused by P. aeruginosa, and reported the prevalence of aimed exoenzymes. RESULTS Ten publications were selected out of 15 full-text reviewed articles with the inclusion criteria. Of ten studies, the pooled prevalence of ExoS producing isolates was estimated at 57.1% (95% CI: 40.3-72.5%). Five studies reported the prevalence of ExoU and ExoT, from which, the pooled prevalence of ExoU and ExoT producing isolates was estimated at 51.4% (95% CI: 31.4-70.9%) and 86.4% (95% CI: 48.1-97.8%), respectively. Four studies reported the prevalence of ExoY, from which, the pooled prevalence of ExoY producing isolates was estimated at 79.0% (95% CI: 48.6-93.8%). CONCLUSION Our results showed a remarkable prevalence of T3SS-positive genotype in patients with burn injuries. These findings provided attractive targets for new therapeutic strategies for burn patients who were infected with cytotoxin-producing P. aeruginosa.
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Affiliation(s)
| | - Alireza Jafari
- Urology Research Center, Razi Hospital, School of Medicine, Guilan University of Medical Sciences, Rasht, Iran
| | - Hoda Sabati
- Biotechnology and Biological Science Research Center, Faculty of Science, Shahid Chamran University of Ahvaz, Iran
| | - Rajendra Goswami
- Institute for Tuberculosis Research, College of Pharmacy, University of Illinois at Chicago, Chicago, IL, USA
| | - Zakiyeh Jafaryparvar
- Razi Clinical Research Development Unit, Razi Hospital, Guilan University of Medical Sciences, Rasht, Iran
| | - Farzaneh Sedaghat
- Student Research Committee, School of Medicine, Guilan University of Medical Sciences, Rasht, Iran
| | - Hadi Sedigh Ebrahim-Saraie
- Razi Clinical Research Development Unit, Razi Hospital, Guilan University of Medical Sciences, Rasht, Iran.
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16
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Riquelme SA, Wong Fok Lung T, Prince A. Pulmonary Pathogens Adapt to Immune Signaling Metabolites in the Airway. Front Immunol 2020; 11:385. [PMID: 32231665 PMCID: PMC7082326 DOI: 10.3389/fimmu.2020.00385] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Accepted: 02/18/2020] [Indexed: 12/17/2022] Open
Abstract
A limited number of pulmonary pathogens are able to evade normal mucosal defenses to establish acute infection and then adapt to cause chronic pneumonias. Pathogens, such as Pseudomonas aeruginosa or Staphylococcus aureus, are typically associated with infection in patients with underlying pulmonary disease or damage, such as cystic fibrosis (CF) or chronic obstructive pulmonary disease (COPD). To establish infection, bacteria express a well-defined set of so-called virulence factors that facilitate colonization and activate an immune response, gene products that have been identified in murine models. Less well-understood are the adaptive changes that occur over time in vivo, enabling the organisms to evade innate and adaptive immune clearance mechanisms. These colonizers proliferate, generating a population sufficient to provide selection for mutants, such as small colony variants and mucoid variants, that are optimized for long term infection. Such host-adapted strains have evolved in response to selective pressure such as antibiotics and the recruitment of phagocytes at sites of infection and their release of signaling metabolites (e.g., succinate). These metabolites can potentially function as substrates for bacterial growth and but also generate oxidant stress. Whole genome sequencing and quantified expression of selected genes have helped to explain how P. aeruginosa and S. aureus adapt to the presence of these metabolites over the course of in vivo infection. The serial isolation of clonally related strains from patients with cystic fibrosis has provided the opportunity to identify bacterial metabolic pathways that are altered under this immune pressure, such as the anti-oxidant glyoxylate and pentose phosphate pathways, routes contributing to the generation of biofilms. These metabolic pathways and biofilm itself enable the organisms to dissipate oxidant stress, while providing protection from phagocytosis. Stimulation of host immune signaling metabolites by these pathogens drives bacterial adaptation and promotes their persistence in the airways. The inherent metabolic flexibility of P. aeruginosa and S. aureus is a major factor in their success as pulmonary pathogens.
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Affiliation(s)
- Sebastián A Riquelme
- Department of Pediatrics, Columbia University Medical Center, New York, NY, United States
| | - Tania Wong Fok Lung
- Department of Pediatrics, Columbia University Medical Center, New York, NY, United States
| | - Alice Prince
- Department of Pediatrics, Columbia University Medical Center, New York, NY, United States
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17
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Dave TV, Dave VP, Sharma S, Karolia R, Joseph J, Pathengay A, Pappuru RR, Das T. Infectious endophthalmitis leading to evisceration: spectrum of bacterial and fungal pathogens and antibacterial susceptibility profile. J Ophthalmic Inflamm Infect 2019; 9:9. [PMID: 31098742 PMCID: PMC6522574 DOI: 10.1186/s12348-019-0174-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Accepted: 05/06/2019] [Indexed: 11/23/2022] Open
Abstract
Purpose To describe the spectrum of bacterial and fungal pathogens in cases of endophthalmitis requiring evisceration and report their antimicrobial susceptibilities. Methods Retrospective, consecutive, and descriptive case series of endophthalmitis that underwent evisceration from January 2004 to December 2017. Vitreous samples from all patients had been investigated for bacteria and fungus using institutional protocol. Bacterial isolates were identified using analytical profile index (API) system until 2010 and Vitek-2 compact system (bioMérieux, France), thereafter. The susceptibility of bacterial isolates to a variety of antibiotics was determined by the Kirby-Bauer disk-diffusion method. Results Of 791 cases reviewed, culture positivity was reported in 388 cases (48.92%). Commonest clinical setting of endophthalmitis necessitating evisceration was post-microbial keratitis (58%), followed by post-trauma and post-cataract surgery (14–15%). The commonest isolate was Streptococcus pneumoniae, seen in 68 samples overall (17.52%). One hundred and eighty-three isolates (47.16%) were gram-positive, 86 (22.16%) were gram-negative, and fungi constituted 137 (35.3%) isolates. Streptococcus pneumoniae was the commonest gram-positive bacterial isolate seen in 68/183 samples (37.15%). Among gram-negative organisms, the commonest was Pseudomonas aeruginosa seen in 47/86 (54.65%). Aspergillus spp. formed the commonest fungal isolate, 58/137 (42.33%). The susceptibility of the gram-positive bacteria was highest with vancomycin, 136/147 (92.51%) and for gram-negative bacteria was seen best with imipenem 24/29 (82.75%). Susceptibility to ceftazidime was 31/61 (50.81%) in 31/61. Conclusion Endophthalmitis due to Pneumococci, Aspergillus, and Pseudomonas can be very fulminant and progress to require evisceration in spite of prompt and appropriate treatment.
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Affiliation(s)
- Tarjani Vivek Dave
- Ophthalmic Plastic Surgery Service, KallamAnji Reddy Campus, LV Prasad Eye Institute, Hyderabad, Telangana, India
| | - Vivek Pravin Dave
- Smt. Kanuri Santhamma Center for Vitreoretinal Diseases, KallamAnji Reddy Campus, LV Prasad Eye Institute, Hyderabad, Telangana, 500034, India.
| | - Savitri Sharma
- Jhaveri Microbiology Center, Brien Holden Eye Research Center, LV Prasad Eye Institute, Hyderabad, India
| | - Roshni Karolia
- Jhaveri Microbiology Center, Brien Holden Eye Research Center, LV Prasad Eye Institute, Hyderabad, India
| | - Joveeta Joseph
- Jhaveri Microbiology Center, Brien Holden Eye Research Center, LV Prasad Eye Institute, Hyderabad, India
| | - Avinash Pathengay
- Retina and Uveitis Department, GMR Varalaxmi Campus, LV Prasad Eye Institute, HanumanthawakaChowk, Visakhapatnam, Andhra Pradesh, 530040, India
| | - Rajeev R Pappuru
- Smt. Kanuri Santhamma Center for Vitreoretinal Diseases, KallamAnji Reddy Campus, LV Prasad Eye Institute, Hyderabad, Telangana, 500034, India
| | - Taraprasad Das
- Smt. Kanuri Santhamma Center for Vitreoretinal Diseases, KallamAnji Reddy Campus, LV Prasad Eye Institute, Hyderabad, Telangana, 500034, India
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18
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Neuhaus M, Munder A, Schipke J, Schmiedl A. Lung infection caused by Pseudomonas aeruginosa in a CD26/DPP4 deficient F344 rat model. Inflamm Res 2019; 68:529-544. [PMID: 31089745 PMCID: PMC7079754 DOI: 10.1007/s00011-019-01236-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 03/27/2019] [Accepted: 04/16/2019] [Indexed: 01/21/2023] Open
Abstract
Background Pseudomonas aeruginosa (PA) is the most important opportunistic pathogen in causing nosocomial infections and, furthermore, poses a permanent threat for severe chronic infections in patients with cystic fibrosis or COPD. The transmembrane protein CD26 with dipeptidyl peptidase-4 (DPP4) activity shows an increased expression in inflamed tissue. We tested whether CD26/DPP4 deficiency leads to reduced inflammation and decreased structural damage when infected with PA. Methods CD26/DPP4+ and CD26/DPP4− rats were instilled intratracheally with NaCl (controls) or with PA. Six hours later, bacterial distribution was detected with the in vivo imaging system 200 (IVIS). Lungs were then processed for molecular biology, light and electron microscopy and analyzed qualitatively, quantitatively and stereologically. Bacterial numbers were determined in homogenized lungs. Results Compared to saline treated controls, in both infected groups (1) the acinar airspace was significantly increased, (2) the volume density of the alveolar epithelium was significantly decreased, (3) the septal thickness was significantly reduced, (4) more than 40% of the alveolar epithelial surface was damaged, and up to 36% of the epithelial surface was covered with edema. In infected CD26− rats, the increase in lung weight was significantly less pronounced, the portion of edematous alveolar airspace was significantly lower and the part of edema interspersed with PA was decreased significantly. Conclusions CD26/DPP4 deficiency resulted in reduced pulmonary edema under sublethal PA infection, implicating a role for CD26 in infection progression. The partly pronounced structural damage may mask further possible influences of CD26 on the inflammatory response.
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Affiliation(s)
- M Neuhaus
- Institute of Functional and Applied Anatomy, Hannover Medical School, Carl-Neuberg-Straße 1, 30625, Hannover, Germany.,Department of Oral and Maxillofacial Surgery, Hannover Medical School, Carl-Neuberg-Straße 1, 30625, Hannover, Germany
| | - A Munder
- Clinic of Pediatric Pneumology, Allergology and Neonatology Hannover Medical School, Carl-Neuberg-Straße 1, 30625, Hannover, Germany.,Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Hannover Medical School, Hannover, Germany
| | - J Schipke
- Institute of Functional and Applied Anatomy, Hannover Medical School, Carl-Neuberg-Straße 1, 30625, Hannover, Germany.,Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Hannover Medical School, Hannover, Germany.,REBIRTH Cluster of Excellence, Hannover Medical School, Hannover, Germany
| | - A Schmiedl
- Institute of Functional and Applied Anatomy, Hannover Medical School, Carl-Neuberg-Straße 1, 30625, Hannover, Germany. .,Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Hannover Medical School, Hannover, Germany. .,REBIRTH Cluster of Excellence, Hannover Medical School, Hannover, Germany.
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19
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Ahn D, Wickersham M, Riquelme S, Prince A. The Effects of IFN-λ on Epithelial Barrier Function Contribute to Klebsiella pneumoniae ST258 Pneumonia. Am J Respir Cell Mol Biol 2019; 60:158-166. [PMID: 30183325 PMCID: PMC6376406 DOI: 10.1165/rcmb.2018-0021oc] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 08/13/2018] [Indexed: 12/13/2022] Open
Abstract
IFN-λ and IL-22, cytokines that share the coreceptor IL-10RB, are both induced over the course of Klebsiella pneumoniae ST258 (KP35) pneumonia. IL-22 is known to protect mucosal barriers, whereas the effects of IFN-λ on the mucosa are not established. We postulated that IFN-λ plays a role in regulating the airway epithelial barrier to facilitate cellular trafficking to the site of infection. In response to IFN-λ, the transmigration of neutrophils across a polarized monolayer of airway epithelial cells was increased, consistent with diminished epithelial integrity. KP35 infection increased epithelial permeability, and pretreatment with IFN-λ amplified this effect and facilitated bacterial transmigration. These effects of IFN-λ were confirmed in vivo, in that mice lacking the receptor for IFN-λ (Ifnlr1-/-) were protected from bacteremia in a murine model of KP35 pneumonia. Conversely, the integrity of the epithelial barrier was protected by IL-22, with subsequent impairment of neutrophil and bacterial transmigration in vitro. Maximal expression of IL-22 in vivo was observed later in the course of infection than IFN-λ production, with high levels of IL-22 produced by recruited immune cells at 48 hours, consistent with a role in epithelial barrier recovery. The divergent and opposing expression of these two related cytokines suggests a regulated interaction in the host response to KP35 infection. A major physiological effect of IFN-λ signaling is a decrease in epithelial barrier integrity, which facilitates immune cell recruitment but also enables K. pneumoniae invasion.
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Affiliation(s)
- Danielle Ahn
- Department of Pediatrics, Columbia University College of Physicians and Surgeons, New York, New York
| | - Matthew Wickersham
- Department of Pediatrics, Columbia University College of Physicians and Surgeons, New York, New York
| | - Sebastian Riquelme
- Department of Pediatrics, Columbia University College of Physicians and Surgeons, New York, New York
| | - Alice Prince
- Department of Pediatrics, Columbia University College of Physicians and Surgeons, New York, New York
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20
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Smallcombe CC, Linfield DT, Harford TJ, Bokun V, Ivanov AI, Piedimonte G, Rezaee F. Disruption of the airway epithelial barrier in a murine model of respiratory syncytial virus infection. Am J Physiol Lung Cell Mol Physiol 2019; 316:L358-L368. [PMID: 30489157 PMCID: PMC6397347 DOI: 10.1152/ajplung.00345.2018] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 11/27/2018] [Accepted: 11/28/2018] [Indexed: 02/08/2023] Open
Abstract
Respiratory syncytial virus (RSV) is a major cause of hospitalization for infants and young children worldwide. RSV is known to infect epithelial cells and increase the permeability of model airway epithelial monolayers in vitro. We hypothesized that RSV infection also induces airway barrier dysfunction in vivo. C57BL/6 mice were intranasally inoculated with RSV, and on day 4 post-inoculation were examined for viral replication, lung inflammation, and barrier integrity as well as the structure and molecular composition of epithelial junctions. In parallel, primary mouse tracheal epithelial cells (mTEC) were cultured for in vitro studies. RSV-infected mice lost weight and showed significant peribronchial inflammation compared with noninfected controls and UV-inactivated RSV-inoculated animals. RSV infection increased the permeability of the airway epithelial barrier and altered the molecular composition of epithelial tight junctions. The observed RSV-induced barrier disruption was accompanied by decreased expression of several tight-junction proteins and accumulation of cleaved extracellular fragments of E-cadherin in bronchoalveolar lavage and mTEC supernatants. Similarly, in vitro RSV infection of mTEC monolayers resulted in enhanced permeability and disruption of tight-junction structure. Furthermore, incubation of mTEC monolayers with a recombinant fragment of E-cadherin caused tight-junction disassembly. Taken together, these data indicate that RSV infection leads to airway barrier dysfunction in vivo, mediated by either decreased expression or cleavage of junctional proteins. Our observations provide further insights into the pathophysiology of RSV infection and provide a rationale for development of barrier-protecting agents to alleviate the pathogenic effects of RSV infection.
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Affiliation(s)
- Carrie C Smallcombe
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic Foundation , Cleveland, Ohio
| | - Debra T Linfield
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic Foundation , Cleveland, Ohio
| | - Terri J Harford
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic Foundation , Cleveland, Ohio
| | - Vladimir Bokun
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic Foundation , Cleveland, Ohio
| | - Andrei I Ivanov
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic Foundation , Cleveland, Ohio
| | - Giovanni Piedimonte
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic Foundation , Cleveland, Ohio
- Center for Pediatric Pulmonary Medicine, Cleveland Clinic Children's , Cleveland, Ohio
| | - Fariba Rezaee
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic Foundation , Cleveland, Ohio
- Center for Pediatric Pulmonary Medicine, Cleveland Clinic Children's , Cleveland, Ohio
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21
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Abstract
PURPOSE Pseudomonas aeruginosa produces pyoverdine, encoded by the pvdE gene, for high-affinity iron uptake from transferrin and lactoferrin. This study investigated the contribution of pyoverdine to P. aeruginosa keratitis pathogenesis using in vitro and in vivo models. METHODS The P. aeruginosa strains examined were parental strain PAO1 and isogenic mutant strain pvdE (ΔpvdE) defective in pyoverdine. Bacterial growth in vitro was determined by PAO1 and ΔpvdE optical densities in Luria-Bertani (LB) broth. PAO1 or ΔpvdE (10 colony-forming units/mL) was inoculated onto cultured human corneal epithelial cells (HCECs) for 1 hour. The monolayers were examined for bacterial adhesion and invasion. In addition, the corneas of C57BL/6 mice were infected with PAO1 or ΔpvdE. Corneal virulence was evaluated by determining clinical scores and bacterial counts during infection. RESULTS The growth of PAO1 and ΔpvdE in LB broth was similar. Although adhesion of ΔpvdE onto HCECs was significantly increased compared with PAO1, the invasive capacity of ΔpvdE was significantly decreased. Clinical scores and bacterial numbers were significantly lower in ΔpvdE-infected eyes compared with PAO1-infected eyes at 6, 24, and 48 hours (P < 0.001). ΔpvdE was not detected in mouse corneas and did not induce corneal opacity at 6, 24, or 48 hours. CONCLUSIONS ΔpvdE lost invasive ability toward HCECs. Moreover, ΔpvdE did not cause keratitis in vivo. Thus, pvdE pyoverdine synthesis has critical roles in proliferation and invasion on ocular surfaces and could be a target for prevention of P. aeruginosa keratitis.
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22
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Hasan S, Sebo P, Osicka R. A guide to polarized airway epithelial models for studies of host-pathogen interactions. FEBS J 2018; 285:4343-4358. [PMID: 29896776 DOI: 10.1111/febs.14582] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 05/21/2018] [Accepted: 06/11/2018] [Indexed: 11/28/2022]
Abstract
Mammalian lungs are organs exhibiting the cellular and spatial complexity required for gas exchange to support life. The respiratory epithelium internally lining the airways is susceptible to infections due to constant exposure to inhaled microbes. Biomedical research into respiratory bacterial infections in humans has been mostly carried out using small mammalian animal models or two-dimensional, submerged cultures of undifferentiated epithelial cells. These experimental model systems have considerable limitations due to host specificity of bacterial pathogens and lack of cellular and morphological complexity. This review describes the in vitro differentiated and polarized airway epithelial cells of human origin that are used as a model to study respiratory bacterial infections. Overall, these models recapitulate key aspects of the complexity observed in vivo and can help in elucidating the molecular details of disease processes observed during respiratory bacterial infections.
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Affiliation(s)
- Shakir Hasan
- Institute of Microbiology of the CAS, v. v. i., Prague, Czech Republic
| | - Peter Sebo
- Institute of Microbiology of the CAS, v. v. i., Prague, Czech Republic
| | - Radim Osicka
- Institute of Microbiology of the CAS, v. v. i., Prague, Czech Republic
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23
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Prashar A, Ortiz ME, Lucarelli S, Barker E, Tabatabeiyazdi Z, Shamoun F, Raju D, Antonescu C, Guyard C, Terebiznik MR. Small Rho GTPases and the Effector VipA Mediate the Invasion of Epithelial Cells by Filamentous Legionella pneumophila. Front Cell Infect Microbiol 2018; 8:133. [PMID: 29774203 PMCID: PMC5943596 DOI: 10.3389/fcimb.2018.00133] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2017] [Accepted: 04/17/2018] [Indexed: 12/13/2022] Open
Abstract
Legionella pneumophila (Lp) exhibits different morphologies with varying degrees of virulence. Despite their detection in environmental sources of outbreaks and in respiratory tract secretions and lung autopsies from patients, the filamentous morphotype of Lp remains poorly studied. We previously demonstrated that filamentous Lp invades lung epithelial cells (LECs) and replicates intracellularly in a Legionella containing vacuole. Filamentous Lp activates β1integrin and E-cadherin receptors at the surface of LECs leading to the formation of actin-rich cell membrane structures we termed hooks and membrane wraps. These structures entrap segments of an Lp filament on host cell surface and mediate bacterial internalization. Here we investigated the molecular mechanisms responsible for the actin rearrangements needed for the formation and elongation of these membrane wraps and bacterial internalization. We combined genetic and pharmacological approaches to assess the contribution of signaling downstream of β1integrin and E-cadherin receptors, and Lp Dot/Icm secretion system- translocated effectors toward the invasion process. Our studies demonstrate a multi-stage mechanism of LEC invasion by filamentous Lp. Bacterial attachment to host cells depends on signaling downstream of β1integrin and E-cadherin activation, leading to Rho GTPases-dependent activation of cellular actin nucleating proteins, Arp2/3 and mDia. This mediates the formation of primordial membrane wraps that entrap the filamentous bacteria on the cell surface. Following this, in a second phase of the invasion process the Dot/Icm translocated effector VipA mediates rapid membrane wrap elongation, leading to the engulfment of the filamentous bacteria by the LECs. Our findings provide the first description of Rho GTPases and a Dot/Icm effector VipA regulating the actin dynamics needed for the invasion of epithelial cells by Lp.
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Affiliation(s)
- Akriti Prashar
- Department of Biological Sciences, University of Toronto at Scarborough, Scarborough, ON, Canada.,Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
| | - María Eugenia Ortiz
- Department of Biological Sciences, University of Toronto at Scarborough, Scarborough, ON, Canada
| | - Stefanie Lucarelli
- Department of Chemistry and Biology, Ryerson University, Toronto, ON, Canada
| | - Elizabeth Barker
- Department of Biological Sciences, University of Toronto at Scarborough, Scarborough, ON, Canada.,Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
| | - Zohreh Tabatabeiyazdi
- Department of Biological Sciences, University of Toronto at Scarborough, Scarborough, ON, Canada.,Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
| | - Feras Shamoun
- Department of Biological Sciences, University of Toronto at Scarborough, Scarborough, ON, Canada
| | - Deepa Raju
- Department of Biological Sciences, University of Toronto at Scarborough, Scarborough, ON, Canada
| | - Costin Antonescu
- Department of Chemistry and Biology, Ryerson University, Toronto, ON, Canada
| | - Cyril Guyard
- Bioaster, Lyon, France.,Molecular Microbiology, Public Health Ontario, Toronto, ON, Canada
| | - Mauricio R Terebiznik
- Department of Biological Sciences, University of Toronto at Scarborough, Scarborough, ON, Canada.,Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
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24
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Golovkine G, Reboud E, Huber P. Pseudomonas aeruginosa Takes a Multi-Target Approach to Achieve Junction Breach. Front Cell Infect Microbiol 2018; 7:532. [PMID: 29379773 PMCID: PMC5770805 DOI: 10.3389/fcimb.2017.00532] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 12/20/2017] [Indexed: 01/17/2023] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen which uses a number of strategies to cross epithelial and endothelial barriers at cell–cell junctions. In this review, we describe how the coordinated actions of P. aeruginosa's virulence factors trigger various molecular mechanisms to disarm the junctional gate responsible for tissue integrity.
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Affiliation(s)
- Guillaume Golovkine
- Centre National de la Recherche Scientifique ERL5261, CEA BIG-BCI, Institut National de la Santé et de la Recherche Médicale UMR1036, Université Grenoble Alpes, Grenoble, France
| | - Emeline Reboud
- Centre National de la Recherche Scientifique ERL5261, CEA BIG-BCI, Institut National de la Santé et de la Recherche Médicale UMR1036, Université Grenoble Alpes, Grenoble, France
| | - Philippe Huber
- Centre National de la Recherche Scientifique ERL5261, CEA BIG-BCI, Institut National de la Santé et de la Recherche Médicale UMR1036, Université Grenoble Alpes, Grenoble, France
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ExoY, an actin-activated nucleotidyl cyclase toxin from P. aeruginosa: A minireview. Toxicon 2017; 149:65-71. [PMID: 29258848 DOI: 10.1016/j.toxicon.2017.12.046] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 12/14/2017] [Accepted: 12/15/2017] [Indexed: 11/23/2022]
Abstract
ExoY is one of four well-characterized Pseudomonas aeruginosa type 3 secretion system (T3SS) effectors. It is a nucleotidyl cyclase toxin that is inactive inside the bacteria, but becomes potently activated once it is delivered into the eukaryotic target cells. Recently, filamentous actin was identified as the eukaryotic cofactor that stimulates specifically ExoY enzymatic activity by several orders of magnitude. In this review, we discuss recent advances in understanding the biochemistry of nucleotidyl cyclase activity of ExoY and its regulation by interaction with filamentous actin.
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26
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Okuda J, Yamane S, Nagata S, Kunikata C, Suezawa C, Yasuda M. The Pseudomonas aeruginosa dnaK gene is involved in bacterial translocation across the intestinal epithelial cell barrier. MICROBIOLOGY-SGM 2017; 163:1208-1216. [PMID: 28758636 DOI: 10.1099/mic.0.000508] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Pseudomonas aeruginosa can penetrate through polarized epithelial cell monolayers produced by the human adenocarcinoma cell line Caco-2. We previously identified genes associated with bacterial translocation through Caco-2 cell monolayers by analysing transposon insertion mutants with dramatically reduced penetration activity relative to that of the wild-type P. aeruginosa PAO1 strain. In this study, we focused on the dnaK mutant because the association between this gene and penetration activity is unknown. Inactivation of dnaK caused significant repression of bacterial penetration through Caco-2 cell monolayers, with decreased swimming, swarming and twitching motilities; bacterial adherence; and fly mortality rate; as well as dramatic repression of type III effector secretion and production of elastase and exotoxin A. However, type IV pilus protein PilA expression was not affected. These results suggest that dnaK is associated with bacterial motility and adherence, which are mediated by flagella and pili, and with toxin secretion, which plays a key role in the penetration of P. aeruginosa through Caco-2 cell monolayers. Inactivation of P. aeruginosa dnaK function may interfere with bacterial translocation and prevent septicaemia caused by P. aeruginosa.
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Affiliation(s)
- Jun Okuda
- Division of Microbiology, Department of Medical Technology, Kagawa Prefectural University of Health Sciences, Kagawa, Japan
| | - Satoshi Yamane
- Division of Microbiology, Department of Medical Technology, Kagawa Prefectural University of Health Sciences, Kagawa, Japan
| | - Syouya Nagata
- Division of Microbiology, Department of Medical Technology, Kagawa Prefectural University of Health Sciences, Kagawa, Japan
| | - Chinami Kunikata
- Division of Microbiology, Department of Medical Technology, Kagawa Prefectural University of Health Sciences, Kagawa, Japan
| | - Chigusa Suezawa
- Division of Microbiology, Department of Medical Technology, Kagawa Prefectural University of Health Sciences, Kagawa, Japan
| | - Masashi Yasuda
- Division of Microbiology, Department of Medical Technology, Kagawa Prefectural University of Health Sciences, Kagawa, Japan
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27
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Tapia R, Kralicek SE, Hecht GA. Modulation of epithelial cell polarity by bacterial pathogens. Ann N Y Acad Sci 2017. [PMID: 28628193 DOI: 10.1111/nyas.13388] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Epithelial cells constitute a physical barrier that aids in protecting the host from microbial pathogens. Polarized epithelial cells contain distinct apical and basolateral membrane domains separated by intercellular junctions, including tight junctions (TJs), which contribute to the maintenance of apical-basal polarity. Polarity complexes also contribute to the establishment of TJ formation. Several pathogens perturb epithelial TJ barrier function and structure in addition to causing a loss of apical-basal polarity. Here, we review the impact of pathogenic bacteria on the disruption of cell-cell junctions and epithelial polarity.
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Affiliation(s)
- Rocio Tapia
- Division of Gastroenterology and Nutrition, Department of Medicine, Loyola University Chicago, Maywood, Illinois
| | - Sarah E Kralicek
- Division of Gastroenterology and Nutrition, Department of Medicine, Loyola University Chicago, Maywood, Illinois
| | - Gail A Hecht
- Division of Gastroenterology and Nutrition, Department of Medicine, Loyola University Chicago, Maywood, Illinois.,Department of Microbiology and Immunology, Loyola University Chicago, Maywood, Illinois.,Edward Hines Jr. VA Hospital, Hines, Illinois
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28
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Ruch TR, Engel JN. Targeting the Mucosal Barrier: How Pathogens Modulate the Cellular Polarity Network. Cold Spring Harb Perspect Biol 2017; 9:cshperspect.a027953. [PMID: 28193722 DOI: 10.1101/cshperspect.a027953] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The mucosal barrier is composed of polarized epithelial cells with distinct apical and basolateral surfaces separated by tight junctions and serves as both a physical and immunological barrier to incoming pathogens. Specialized polarity proteins are critical for establishment and maintenance of polarity. Many human pathogens have evolved virulence mechanisms that target the polarity network to enhance binding, create replication niches, move through the barrier by transcytosis, or bypass the barrier by disrupting cell-cell junctions. This review summarizes recent advances and compares and contrasts how three important human pathogens that colonize mucosal surfaces, Pseudomonas aeruginosa, Helicobacter pylori, and Neisseria meningitidis, subvert the host cell polarization machinery during infection.
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Affiliation(s)
- Travis R Ruch
- Department of Medicine, University of California, San Francisco, San Francisco, California 94143
| | - Joanne N Engel
- Department of Medicine, University of California, San Francisco, San Francisco, California 94143.,Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, California 94143
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29
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Crabbé A, Liu Y, Matthijs N, Rigole P, De La Fuente-Nùñez C, Davis R, Ledesma MA, Sarker S, Van Houdt R, Hancock REW, Coenye T, Nickerson CA. Antimicrobial efficacy against Pseudomonas aeruginosa biofilm formation in a three-dimensional lung epithelial model and the influence of fetal bovine serum. Sci Rep 2017; 7:43321. [PMID: 28256611 PMCID: PMC5335707 DOI: 10.1038/srep43321] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 01/25/2017] [Indexed: 12/14/2022] Open
Abstract
In vitro models that mimic in vivo host-pathogen interactions are needed to evaluate candidate drugs that inhibit bacterial virulence traits. We established a new approach to study Pseudomonas aeruginosa biofilm susceptibility on biotic surfaces, using a three-dimensional (3-D) lung epithelial cell model. P. aeruginosa formed antibiotic resistant biofilms on 3-D cells without affecting cell viability. The biofilm-inhibitory activity of antibiotics and/or the anti-biofilm peptide DJK-5 were evaluated on 3-D cells compared to a plastic surface, in medium with and without fetal bovine serum (FBS). In both media, aminoglycosides were more efficacious in the 3-D cell model. In serum-free medium, most antibiotics (except polymyxins) showed enhanced efficacy when 3-D cells were present. In medium with FBS, colistin was less efficacious in the 3-D cell model. DJK-5 exerted potent inhibition of P. aeruginosa association with both substrates, only in serum-free medium. DJK-5 showed stronger inhibitory activity against P. aeruginosa associated with plastic compared to 3-D cells. The combined addition of tobramycin and DJK-5 exhibited more potent ability to inhibit P. aeruginosa association with both substrates. In conclusion, lung epithelial cells influence the efficacy of most antimicrobials against P. aeruginosa biofilm formation, which in turn depends on the presence or absence of FBS.
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Affiliation(s)
- Aurélie Crabbé
- Laboratory of Pharmaceutical Microbiology (LPM), Ghent University, Ghent, Belgium.,The Biodesign Institute, Center for Infectious Diseases and Vaccinology, Arizona State University, Tempe, Arizona, United States of America
| | - Yulong Liu
- The Biodesign Institute, Center for Infectious Diseases and Vaccinology, Arizona State University, Tempe, Arizona, United States of America
| | - Nele Matthijs
- Laboratory of Pharmaceutical Microbiology (LPM), Ghent University, Ghent, Belgium
| | - Petra Rigole
- Laboratory of Pharmaceutical Microbiology (LPM), Ghent University, Ghent, Belgium
| | - César De La Fuente-Nùñez
- University of British Columbia, Centre for Microbial Diseases and Immunity Research, Vancouver, British Columbia, Canada
| | - Richard Davis
- The Biodesign Institute, Center for Infectious Diseases and Vaccinology, Arizona State University, Tempe, Arizona, United States of America
| | - Maria A Ledesma
- The Biodesign Institute, Center for Infectious Diseases and Vaccinology, Arizona State University, Tempe, Arizona, United States of America
| | - Shameema Sarker
- The Biodesign Institute, Center for Infectious Diseases and Vaccinology, Arizona State University, Tempe, Arizona, United States of America
| | - Rob Van Houdt
- Unit of Microbiology, Belgian Nuclear Research Centre (SCK·CEN), Mol, Belgium
| | - Robert E W Hancock
- University of British Columbia, Centre for Microbial Diseases and Immunity Research, Vancouver, British Columbia, Canada
| | - Tom Coenye
- Laboratory of Pharmaceutical Microbiology (LPM), Ghent University, Ghent, Belgium
| | - Cheryl A Nickerson
- The Biodesign Institute, Center for Infectious Diseases and Vaccinology, Arizona State University, Tempe, Arizona, United States of America.,School of Life Sciences, Arizona State University, Tempe, Arizona 85287, United States of America
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30
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Cai S, Li Y, Wang K, Cen Y, Lu H, Dong B, Chen Y, Kong J. Pathogenic Effects of Biofilm on Pseudomonas Aeruginosa Pulmonary Infection and Its Relationship to Cytokines. Med Sci Monit 2016; 22:4869-4874. [PMID: 27941713 PMCID: PMC5156558 DOI: 10.12659/msm.898783] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Background An animal (Sprague-Dawley rat) model of Pseudomonas aeruginosa biofilm associated with chronic pulmonary infection in vivo was established and the effects of the biofilm on P. aeruginosa and its relationship to cytokines were investigated. Material/Methods Biofilm of P. aeruginosa in alginate beads and planktonic PA0725 were purified by anion-exchange chromatograph. Sprague-Dawley (SD) rats were immunized with the biofilm and then inhaled the same strain of P. aeruginosa. Anti-biofilm antibody titer was detected using the enzyme linked immunosorbent assay (ELISA) method. The cell count and differential count in the bronchoalveolar lavage fluid (BALF) were measured. The levels of cytokines (IL-17, IL-1β, MIP-2, and G-CSF) and tumor necrosis factor (TNF)-α in sera were also measured using an ELISA kit. Results The sera anti-biofilm IgG antibody titer of immunized SD rats was increased significantly on the 5th and 8th days after inhalation. The IL-17 concentration was significantly higher on the 8th day after inhalation. The results indicated that when biofilm-pre-immunized rats were challenged with inhalation of PA0725 of P. aeruginosa, the biofilm acted as an antigen substance and mediated the antibody reaction of the antigen, which might cause serious airway inflammatory response and lung tissue injury. This effect may be related to IL-17. Conclusions P. aeruginosa biofilm protected the bacterium from antibiotics and might induce host immune damage in lung tissue and facilitate bacterium evading the host barrier.
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Affiliation(s)
- Shuangqi Cai
- Department of Respiratory Disease, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China (mainland)
| | - Yanan Li
- Department of Respiratory Disease, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China (mainland)
| | - Ke Wang
- Department of Respiratory Disease, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China (mainland)
| | - Yanling Cen
- Department of Respiratory Disease, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China (mainland)
| | - Huasong Lu
- Department of Respiratory Disease, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China (mainland)
| | - Biying Dong
- Department of Respiratory Disease, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China (mainland)
| | - Yiqiang Chen
- Department of Respiratory Disease, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China (mainland)
| | - Jinliang Kong
- Department of Respiratory Disease, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China (mainland)
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31
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Blume C, David J, Bell RE, Laver JR, Read RC, Clark GC, Davies DE, Swindle EJ. Modulation of Human Airway Barrier Functions during Burkholderia thailandensis and Francisella tularensis Infection Running Title: Airway Barrier Functions during Bacterial Infections. Pathogens 2016; 5:pathogens5030053. [PMID: 27527221 PMCID: PMC5039433 DOI: 10.3390/pathogens5030053] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Revised: 07/25/2016] [Accepted: 07/26/2016] [Indexed: 11/16/2022] Open
Abstract
The bronchial epithelium provides protection against pathogens from the inhaled environment through the formation of a highly-regulated barrier. In order to understand the pulmonary diseases melioidosis and tularemia caused by Burkholderia thailandensis and Fransicella tularensis, respectively, the barrier function of the human bronchial epithelium were analysed. Polarised 16HBE14o- or differentiated primary human bronchial epithelial cells (BECs) were exposed to increasing multiplicities of infection (MOI) of B. thailandensis or F. tularensis Live Vaccine Strain and barrier responses monitored over 24-72 h. Challenge of polarized BECs with either bacterial species caused an MOI- and time-dependent increase in ionic permeability, disruption of tight junctions, and bacterial passage from the apical to the basolateral compartment. B. thailandensis was found to be more invasive than F. tularensis. Both bacterial species induced an MOI-dependent increase in TNF-α release. An increase in ionic permeability and TNF-α release was induced by B. thailandensis in differentiated BECs. Pretreatment of polarised BECs with the corticosteroid fluticasone propionate reduced bacterial-dependent increases in ionic permeability, bacterial passage, and TNF-α release. TNF blocking antibody Enbrel(®) reduced bacterial passage only. BEC barrier properties are disrupted during respiratory bacterial infections and targeting with corticosteroids or anti-TNF compounds may represent a therapeutic option.
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Affiliation(s)
- Cornelia Blume
- Academic Unit of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, University Hospital Southampton, Tremona Road, Southampton SO16 6YD, UK.
| | - Jonathan David
- Defence Science and Technology Laboratory (Dstl), Porton Down, Salisbury SP4 0JQ, UK.
| | - Rachel E Bell
- Defence Science and Technology Laboratory (Dstl), Porton Down, Salisbury SP4 0JQ, UK.
- Centre for Molecular and Cellular Biology of Inflammation, Guy's Campus, King's College London, London SE1 1UL, UK.
| | - Jay R Laver
- Academic Unit of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, University Hospital Southampton, Tremona Road, Southampton SO16 6YD, UK.
| | - Robert C Read
- Academic Unit of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, University Hospital Southampton, Tremona Road, Southampton SO16 6YD, UK.
- Southampton NIHR Respiratory Biomedical Research Unit, University Hospital Southampton, Southampton SO16 6YD, UK.
- Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, UK.
| | - Graeme C Clark
- Defence Science and Technology Laboratory (Dstl), Porton Down, Salisbury SP4 0JQ, UK.
| | - Donna E Davies
- Academic Unit of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, University Hospital Southampton, Tremona Road, Southampton SO16 6YD, UK.
- Southampton NIHR Respiratory Biomedical Research Unit, University Hospital Southampton, Southampton SO16 6YD, UK.
- Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, UK.
| | - Emily J Swindle
- Academic Unit of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, University Hospital Southampton, Tremona Road, Southampton SO16 6YD, UK.
- Southampton NIHR Respiratory Biomedical Research Unit, University Hospital Southampton, Southampton SO16 6YD, UK.
- Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, UK.
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32
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Parker D, Ahn D, Cohen T, Prince A. Innate Immune Signaling Activated by MDR Bacteria in the Airway. Physiol Rev 2016; 96:19-53. [PMID: 26582515 DOI: 10.1152/physrev.00009.2015] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Health care-associated bacterial pneumonias due to multiple-drug resistant (MDR) pathogens are an important public health problem and are major causes of morbidity and mortality worldwide. In addition to antimicrobial resistance, these organisms have adapted to the milieu of the human airway and have acquired resistance to the innate immune clearance mechanisms that normally prevent pneumonia. Given the limited efficacy of antibiotics, bacterial clearance from the airway requires an effective immune response. Understanding how specific airway pathogens initiate and regulate innate immune signaling, and whether this response is excessive, leading to host-induced pathology may guide future immunomodulatory therapy. We will focus on three of the most important causes of health care-associated pneumonia, Staphylococcus aureus, Pseudomonas aeruginosa, and Klebsiella pneumoniae, and review the mechanisms through which an inappropriate or damaging innate immune response is stimulated, as well as describe how airway pathogens cause persistent infection by evading immune activation.
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Affiliation(s)
- Dane Parker
- Departments of Pediatrics and Pharmacology, Columbia University, New York, New York
| | - Danielle Ahn
- Departments of Pediatrics and Pharmacology, Columbia University, New York, New York
| | - Taylor Cohen
- Departments of Pediatrics and Pharmacology, Columbia University, New York, New York
| | - Alice Prince
- Departments of Pediatrics and Pharmacology, Columbia University, New York, New York
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33
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Pseudomonas aeruginosa Transmigrates at Epithelial Cell-Cell Junctions, Exploiting Sites of Cell Division and Senescent Cell Extrusion. PLoS Pathog 2016; 12:e1005377. [PMID: 26727615 PMCID: PMC4699652 DOI: 10.1371/journal.ppat.1005377] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 12/09/2015] [Indexed: 12/19/2022] Open
Abstract
To achieve systemic infection, bacterial pathogens must overcome the critical and challenging step of transmigration across epithelial barriers. This is particularly true for opportunistic pathogens such as Pseudomonas aeruginosa, an agent which causes nosocomial infections. Despite extensive study, details on the mechanisms used by this bacterium to transmigrate across epithelial tissues, as well as the entry sites it uses, remain speculative. Here, using real-time microscopy and a model epithelial barrier, we show that P. aeruginosa employs a paracellular transmigration route, taking advantage of altered cell-cell junctions at sites of cell division or when senescent cells are expelled from the cell layer. Once a bacterium transmigrates, it is followed by a cohort of bacteria using the same entry point. The basal compartment is then invaded radially from the initial penetration site. Effective transmigration and propagation require type 4 pili, the type 3 secretion system (T3SS) and a flagellum, although flagellum-deficient bacteria can occasionally invade the basal compartment from wounded areas. In the basal compartment, the bacteria inject the T3SS toxins into host cells, disrupting the cytoskeleton and focal contacts to allow their progression under the cells. Thus, P. aeruginosa exploits intrinsic host cell processes to breach the epithelium and invade the subcellular compartment. In normal situations, the mucosae constitute efficient barriers against the invasion of opportunistic pathogens. The bacteria inducing nosocomial infections take advantage of pre-existing pathological situations to cross the epithelium and spread in deeper tissues. The conditions on the host side permitting transmigration and the combination of virulence factors used by the bacteria to transmigrate are mostly speculative. Here, we studied the transmigration process of Pseudomonas aeruginosa, a bacterium causing hospital-acquired acute and chronic infections. We found that bacteria exploits weakened cell-cell junctions of the epithelium, such as those generated at sites of cell division or when dying cells are extruded from the cell layer, to breach the cell layer, using specific virulence factors and motility appendages.
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34
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Benediktsdottir BE, Baldursson O, Gudjonsson T, Tønnesen HH, Masson M. Curcumin, bisdemethoxycurcumin and dimethoxycurcumin complexed with cyclodextrins have structure specific effect on the paracellular integrity of lung epithelia in vitro. Biochem Biophys Rep 2015; 4:405-410. [PMID: 29124231 PMCID: PMC5669517 DOI: 10.1016/j.bbrep.2015.11.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Revised: 10/31/2015] [Accepted: 11/05/2015] [Indexed: 11/17/2022] Open
Abstract
The phytochemical curcumin may improve translocation of the cystic fibrosis transmembrane regulatory (CFTR) protein in lung epithelium and therefore be helpful in the treatment of cystic fibrosis (CF) symptoms. However, previous studies often use commercial curcumin that is a combination of curcumin, demethoxycurcumin and bisdemethoxycurcumin which could affect the investigated cells differently. In the present study, we investigated the potential difference between curcumin, bisdemethoxycurcumin and dimethoxycurcumin on the epithelial tight junction complex, in the bronchial epithelial cell line VA10, by measuring transepithelial electrical resistance (TER), immunofluorescence and western blotting of tight junction proteins. The curcuminoids were complexed with hydroxypropyl-γ–cyclodextrin for increased solubility and stability. Curcumin (10 µg/ml) increased the TER significantly after 24 h of treatment while four times higher concentration of bisdemethoxycurcumin was required to obtain similar increase in TER as curcumin. Interestingly, dimethoxycurcumin did not increase TER. Curcumin clearly affected the F-actin structures both apically and basolaterally. These results begin to define possible effects of curcuminoids on healthy bronchial epithelia and shows that difference in the phenyl moiety structure of the curcuminoids influences the paracellular epithelial integrity. Curcuminoids formulized with cyclodextrin for increased solubility and stability. Curcumin increases TER in a concentration dependent manner and causes decrease in apical F-actin staining. Higher concentration required for bisdemethoxycurcumin to increase TER compared to curcumin. Dimethoxycurcumin did not increase TER.
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Affiliation(s)
- Berglind Eva Benediktsdottir
- Faculty of Pharmaceutical Sciences, School of Health Sciences, University of Iceland, Hofsvallagata 53, IS-107 Reykjavik, Iceland
| | - Olafur Baldursson
- Department of Pulmonary Medicine, Landspitali-The National University Hospital of Iceland, Eiríksgata 5, IS-101 Reykjavík, Iceland
| | - Thorarinn Gudjonsson
- Biomedical Center, School of Health Sciences, University of Iceland, Vatnsmýrarvegur 16, IS-101 Reykjavík, Iceland
| | - Hanne Hjorth Tønnesen
- School of Pharmacy, Dept. of Pharmaceutics, University of Oslo, Blindern, 0136 Oslo, Norway
| | - Mar Masson
- Faculty of Pharmaceutical Sciences, School of Health Sciences, University of Iceland, Hofsvallagata 53, IS-107 Reykjavik, Iceland
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35
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Berube BJ, Rangel SM, Hauser AR. Pseudomonas aeruginosa: breaking down barriers. Curr Genet 2015; 62:109-13. [PMID: 26407972 DOI: 10.1007/s00294-015-0522-x] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Revised: 09/15/2015] [Accepted: 09/16/2015] [Indexed: 12/26/2022]
Abstract
Many bacterial pathogens have evolved ingenious ways to escape from the lung during pneumonia to cause bacteremia. Unfortunately, the clinical consequences of this spread to the bloodstream are frequently dire. It is therefore important to understand the molecular mechanisms used by pathogens to breach the lung barrier. We have recently shown that Pseudomonas aeruginosa, one of the leading causes of hospital-acquired pneumonia, utilizes the type III secretion system effector ExoS to intoxicate pulmonary epithelial cells. Injection of these cells leads to localized disruption of the pulmonary-vascular barrier and dissemination of P. aeruginosa to the bloodstream. We put these data in the context of previous studies to provide a holistic model of P. aeruginosa dissemination from the lung. Finally, we compare P. aeruginosa dissemination to that of other bacteria to highlight the complexity of bacterial pneumonia. Although respiratory pathogens use distinct and intricate strategies to escape from the lungs, a thorough understanding of these processes can lay the foundation for new therapeutic approaches for bacterial pneumonia.
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Affiliation(s)
- Bryan J Berube
- Department of Microbiology-Immunology, Northwestern University, 303 E. Chicago Ave., Chicago, IL, 60611, USA
| | - Stephanie M Rangel
- Department of Microbiology-Immunology, Northwestern University, 303 E. Chicago Ave., Chicago, IL, 60611, USA
| | - Alan R Hauser
- Department of Microbiology-Immunology, Northwestern University, 303 E. Chicago Ave., Chicago, IL, 60611, USA. .,Department of Medicine, Northwestern University, Chicago, IL, USA.
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36
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The Role of ExoS in Dissemination of Pseudomonas aeruginosa during Pneumonia. PLoS Pathog 2015; 11:e1004945. [PMID: 26090668 PMCID: PMC4474835 DOI: 10.1371/journal.ppat.1004945] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Accepted: 05/11/2015] [Indexed: 01/11/2023] Open
Abstract
Hospital-acquired pneumonia is associated with high rates of morbidity and mortality, and dissemination to the bloodstream is a recognized risk factor for particularly poor outcomes. Yet the mechanism by which bacteria in the lungs gain access to the bloodstream remains poorly understood. In this study, we used a mouse model of Pseudomonas aeruginosa pneumonia to examine this mechanism. P. aeruginosa uses a type III secretion system to deliver effector proteins such as ExoS directly into the cytosol of eukaryotic cells. ExoS, a bi-functional GTPase activating protein (GAP) and ADP-ribosyltransferase (ADPRT), inhibits phagocytosis during pneumonia but has also been linked to a higher incidence of dissemination to the bloodstream. We used a novel imaging methodology to identify ExoS intoxicated cells during pneumonia and found that ExoS is injected into not only leukocytes but also epithelial cells. Phagocytic cells, primarily neutrophils, were targeted for injection with ExoS early during infection, but type I pneumocytes became increasingly injected at later time points. Interestingly, injection of these pneumocytes did not occur randomly but rather in discrete regions, which we designate ““fields of cell injection” (FOCI). These FOCI increased in size as the infection progressed and contained dead type I pneumocytes. Both of these phenotypes were attenuated in infections caused by bacteria secreting ADPRT-deficient ExoS, indicating that FOCI growth and type I pneumocyte death were dependent on the ADPRT activity of ExoS. During the course of infection, increased FOCI size was associated with enhanced disruption of the pulmonary-vascular barrier and increased bacterial dissemination into the blood, both of which were also dependent on the ADPRT activity of ExoS. We conclude that the ADPRT activity of ExoS acts upon type I pneumocytes to disrupt the pulmonary-vascular barrier during P. aeruginosa pneumonia, leading to bacterial dissemination. Dissemination to the bloodstream is a poor prognostic sign in patients with hospital-acquired pneumonia, yet the mechanism by which this occurs is poorly understood. To begin to address this issue, we have used a mouse model of P. aeruginosa pneumonia to study the mechanism by which the type-III-secreted effector protein ExoS enhances bacterial dissemination. We show that intoxication of type I pneumocytes by ExoS leads to cell death and disruption of the pulmonary-vascular barrier, allowing bacterial dissemination into the bloodstream. These effects required the ADP-ribosyltransferase activity of ExoS, as strains secreting an ExoS variant lacking this activity demonstrated reduced type I pneumocytes death and pulmonary-vascular breakdown. This study indicates that inhibitors of the ADP-ribosyltransferase activity of ExoS could serve as novel therapeutics for the prevention of bacteremic pneumonia.
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37
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van ‘t Wout EFA, van Schadewijk A, van Boxtel R, Dalton LE, Clarke HJ, Tommassen J, Marciniak SJ, Hiemstra PS. Virulence Factors of Pseudomonas aeruginosa Induce Both the Unfolded Protein and Integrated Stress Responses in Airway Epithelial Cells. PLoS Pathog 2015; 11:e1004946. [PMID: 26083346 PMCID: PMC4471080 DOI: 10.1371/journal.ppat.1004946] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Accepted: 05/11/2015] [Indexed: 12/20/2022] Open
Abstract
Pseudomonas aeruginosa infection can be disastrous in chronic lung diseases such as cystic fibrosis and chronic obstructive pulmonary disease. Its toxic effects are largely mediated by secreted virulence factors including pyocyanin, elastase and alkaline protease (AprA). Efficient functioning of the endoplasmic reticulum (ER) is crucial for cell survival and appropriate immune responses, while an excess of unfolded proteins within the ER leads to “ER stress” and activation of the “unfolded protein response” (UPR). Bacterial infection and Toll-like receptor activation trigger the UPR most likely due to the increased demand for protein folding of inflammatory mediators. In this study, we show that cell-free conditioned medium of the PAO1 strain of P. aeruginosa, containing secreted virulence factors, induces ER stress in primary bronchial epithelial cells as evidenced by splicing of XBP1 mRNA and induction of CHOP, GRP78 and GADD34 expression. Most aspects of the ER stress response were dependent on TAK1 and p38 MAPK, except for the induction of GADD34 mRNA. Using various mutant strains and purified virulence factors, we identified pyocyanin and AprA as inducers of ER stress. However, the induction of GADD34 was mediated by an ER stress-independent integrated stress response (ISR) which was at least partly dependent on the iron-sensing eIF2α kinase HRI. Our data strongly suggest that this increased GADD34 expression served to protect against Pseudomonas-induced, iron-sensitive cell cytotoxicity. In summary, virulence factors from P. aeruginosa induce ER stress in airway epithelial cells and also trigger the ISR to improve cell survival of the host. Pseudomonas aeruginosa causes a devastating infection when it affects patients with cystic fibrosis or other chronic lung diseases. It often causes chronic infection due to its resistance to antibiotic treatment and its ability to form biofilms in these patients. The toxic effects of P. aeruginosa are largely mediated by secreted virulence factors. Efficient functioning of the endoplasmic reticulum is crucial for cell survival and appropriate immune responses, while its dysfunction causes stress and activation of the unfolded protein response. In this study, we found that virulence factors secreted by P. aeruginosa trigger the unfolded protein response in human cells by causing endoplasmic reticulum stress. In addition, secreted virulence factors activate the integrated stress response via a parallel independent pathway. Both stress pathways lead to the induction of the protein GADD34, which appears to provide protection against the toxic effects of the secreted virulence factors.
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Affiliation(s)
- Emily F. A. van ‘t Wout
- Department of Pulmonology, Leiden University Medical Centre, Leiden, the Netherlands
- Cambridge Institute for Medical Research (CIMR), University of Cambridge, Cambridge, United Kingdom
| | | | - Ria van Boxtel
- Department of Molecular Microbiology, Utrecht University, Utrecht, the Netherlands
| | - Lucy E. Dalton
- Cambridge Institute for Medical Research (CIMR), University of Cambridge, Cambridge, United Kingdom
| | - Hanna J. Clarke
- Cambridge Institute for Medical Research (CIMR), University of Cambridge, Cambridge, United Kingdom
| | - Jan Tommassen
- Department of Molecular Microbiology, Utrecht University, Utrecht, the Netherlands
| | - Stefan J. Marciniak
- Cambridge Institute for Medical Research (CIMR), University of Cambridge, Cambridge, United Kingdom
| | - Pieter S. Hiemstra
- Department of Pulmonology, Leiden University Medical Centre, Leiden, the Netherlands
- * E-mail:
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Hayashi N, Nishizawa H, Kitao S, Deguchi S, Nakamura T, Fujimoto A, Shikata M, Gotoh N. Pseudomonas aeruginosa injects type III effector ExoS into epithelial cells through the function of type IV pili. FEBS Lett 2015; 589:890-6. [PMID: 25747138 DOI: 10.1016/j.febslet.2015.02.031] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2014] [Revised: 02/02/2015] [Accepted: 02/25/2015] [Indexed: 12/29/2022]
Abstract
Translocation of Pseudomonas aeruginosa through epithelial tissues can cause sepsis. Here, we examined whether P. aeruginosa penetrates epithelial cell layers using type IV pili (TFP). Deletion of TFP (pilA) did not affect association with Caco-2 cells, although it decreased penetration through, and disruption of, Caco-2 cell monolayers. We found that TFP are necessary for injection of the type III effector ExoS, which impairs defense against P. aeruginosa penetration, into host cells. Deletion of pilA attenuated oral infection in silkworms. We conclude that P. aeruginosa injects ExoS into cells through the function of TFP, enabling penetration of epithelial barriers.
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Affiliation(s)
- Naoki Hayashi
- Department of Microbiology and Infection Control Science, Kyoto Pharmaceutical University, Kyoto 607-8414, Japan
| | - Hideyuki Nishizawa
- Department of Microbiology and Infection Control Science, Kyoto Pharmaceutical University, Kyoto 607-8414, Japan
| | - Seiya Kitao
- Department of Microbiology and Infection Control Science, Kyoto Pharmaceutical University, Kyoto 607-8414, Japan
| | - Sakurako Deguchi
- Department of Microbiology and Infection Control Science, Kyoto Pharmaceutical University, Kyoto 607-8414, Japan
| | - Takano Nakamura
- Department of Microbiology and Infection Control Science, Kyoto Pharmaceutical University, Kyoto 607-8414, Japan
| | - Akiyo Fujimoto
- Department of Microbiology and Infection Control Science, Kyoto Pharmaceutical University, Kyoto 607-8414, Japan
| | - Mototsugu Shikata
- Department of Microbiology and Infection Control Science, Kyoto Pharmaceutical University, Kyoto 607-8414, Japan
| | - Naomasa Gotoh
- Department of Microbiology and Infection Control Science, Kyoto Pharmaceutical University, Kyoto 607-8414, Japan.
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The importance of the Pseudomonas aeruginosa type III secretion system in epithelium traversal depends upon conditions of host susceptibility. Infect Immun 2015; 83:1629-40. [PMID: 25667266 DOI: 10.1128/iai.02329-14] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Pseudomonas aeruginosa is invasive or cytotoxic to host cells, depending on the type III secretion system (T3SS) effectors encoded. While the T3SS is known to be involved in disease in vivo, how it participates remains to be clarified. Here, mouse models of superficial epithelial injury (tissue paper blotting with EGTA treatment) and immunocompromise (MyD88 deficiency) were used to study the contribution of the T3SS transcriptional activator ExsA to epithelial traversal. Corneas of excised eyeballs were inoculated with green fluorescent protein (GFP)-expressing PAO1 or isogenic exsA mutants for 6 h ex vivo before bacterial traversal and epithelial thickness were quantified by using imaging. In the blotting-EGTA model, exsA mutants were defective in capacity for traversal. Accordingly, an ∼16-fold variability in exsA expression among PAO1 isolates from three sources correlated with epithelial loss. In contrast, MyD88-/- epithelia remained susceptible to P. aeruginosa traversal despite exsA mutation. Epithelial lysates from MyD88-/- mice had reduced antimicrobial activity compared to those from wild-type mice with and without prior antigen challenge, particularly 30- to 100-kDa fractions, for which mass spectrometry revealed multiple differences, including (i) lower baseline levels of histones, tubulin, and lumican and (ii) reduced glutathione S-transferase, annexin, and dermatopontin, after antigen challenge. Thus, the importance of ExsA in epithelial traversal by invasive P. aeruginosa depends on the compromise enabling susceptibility, suggesting that strategies for preventing infection will need to extend beyond targeting the T3SS. The data also highlight the importance of mimicking conditions allowing susceptibility in animal models and the need to monitor variability among bacterial isolates from different sources, even for the same strain.
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Nassour H, Dubreuil JD. Escherichia coli STb enterotoxin dislodges claudin-1 from epithelial tight junctions. PLoS One 2014; 9:e113273. [PMID: 25409315 PMCID: PMC4237405 DOI: 10.1371/journal.pone.0113273] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Accepted: 10/25/2014] [Indexed: 12/26/2022] Open
Abstract
Enterotoxigenic Escherichia coli produce various heat-labile and heat-stable enterotoxins. STb is a low molecular weight heat-resistant toxin responsible for diarrhea in farm animals, mainly young pigs. A previous study demonstrated that cells having internalized STb toxin induce epithelial barrier dysfunction through changes in tight junction (TJ) proteins. These modifications contribute probably to the diarrhea observed. To gain insight into the mechanism of increased intestinal permeability following STb exposure we treated human colon cells (T84) with purified STb toxin after which cells were harvested and proteins extracted. Using a 1% Nonidet P-40-containing solution we investigated the distribution of claudin-1, a major structural and functional TJ protein responsible for the epithelium impermeability, between membrane (NP40-insoluble) and the cytoplasmic (NP-40 soluble) location. Using immunoblot and confocal microscopy, we observed that treatment of T84 cell monolayers with STb induced redistribution of claudin-1. After 24 h, cells grown in Ca++-free medium treated with STb showed about 40% more claudin-1 in the cytoplasm compare to the control. Switching from Ca++-free to Ca++-enriched medium (1.8 mM) increased the dislodgement rate of claudin-1 as comparable quantitative delocalization was observed after only 6 h. Medium supplemented with the same concentration of Mg++ or Zn++ did not affect the dislodgement rate compared to the Ca++-free medium. Using anti-phosphoserine and anti-phosphothreonine antibodies, we observed that the loss of membrane claudin-1 was accompanied by dephosphorylation of this TJ protein. Overall, our findings showed an important redistribution of claudin-1 in cells treated with STb toxin. The loss of phosphorylated TJ membrane claudin-1 is likely to be involved in the increased permeability observed. The mechanisms by which these changes are brought about remain to be elucidated.
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Affiliation(s)
- Hassan Nassour
- GREMIP, Faculty of Veterinary Medicine, Université de Montréal, Montreal, Quebec, Canada
| | - J Daniel Dubreuil
- GREMIP, Faculty of Veterinary Medicine, Université de Montréal, Montreal, Quebec, Canada
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Quiros M, Nusrat A. RhoGTPases, actomyosin signaling and regulation of the epithelial Apical Junctional Complex. Semin Cell Dev Biol 2014; 36:194-203. [PMID: 25223584 DOI: 10.1016/j.semcdb.2014.09.003] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2014] [Revised: 08/28/2014] [Accepted: 09/04/2014] [Indexed: 12/22/2022]
Abstract
Epithelial cells form regulated and selective barriers between distinct tissue compartments. The Apical Junctional Complex (AJC) consisting of the tight junction (TJ) and adherens junction (AJ) control epithelial homeostasis, paracellular permeability and barrier properties. The AJC is composed of mutliprotein complexes consisting of transmembrane proteins that affiliate with an underlying perijunctional F-actin myosin ring through cytoplasmic scaffold proteins. AJC protein associations with the apical actin-myosin cytoskeleton are tightly controlled by a number of signaling proteins including the Rho family of GTPases that orchestrate junctional biology, epithelial homeostasis and barrier function. This review highlights the vital relationship of Rho GTPases and AJCs in controlling the epithelial barrier. The pathophysiologic relationship of Rho GTPases, AJC, apical actomyosin cytoskeleton and epithelial barrier function is discussed.
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Affiliation(s)
- Miguel Quiros
- Epithelial Pathobiology and Mucosal Inflammation Research Unit, Department of Pathology & Laboratory Medicine, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Asma Nusrat
- Epithelial Pathobiology and Mucosal Inflammation Research Unit, Department of Pathology & Laboratory Medicine, Emory University School of Medicine, Atlanta, GA 30322, USA.
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Junkins RD, Carrigan SO, Wu Z, Stadnyk AW, Cowley E, Issekutz T, Berman J, Lin TJ. Mast Cells Protect against Pseudomonas aeruginosa–Induced Lung Injury. THE AMERICAN JOURNAL OF PATHOLOGY 2014; 184:2310-21. [DOI: 10.1016/j.ajpath.2014.05.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Revised: 04/07/2014] [Accepted: 05/12/2014] [Indexed: 01/09/2023]
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Crabbé A, Ledesma MA, Nickerson CA. Mimicking the host and its microenvironment in vitro for studying mucosal infections by Pseudomonas aeruginosa. Pathog Dis 2014; 71:1-19. [PMID: 24737619 DOI: 10.1111/2049-632x.12180] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Revised: 04/09/2014] [Accepted: 04/09/2014] [Indexed: 02/01/2023] Open
Abstract
Why is a healthy person protected from Pseudomonas aeruginosa infections, while individuals with cystic fibrosis or damaged epithelium are particularly susceptible to this opportunistic pathogen? To address this question, it is essential to thoroughly understand the dynamic interplay between the host microenvironment and P. aeruginosa. Therefore, using model systems that represent key aspects of human mucosal tissues in health and disease allows recreating in vivo host-pathogen interactions in a physiologically relevant manner. In this review, we discuss how factors of mucosal tissues, such as apical-basolateral polarity, junctional complexes, extracellular matrix proteins, mucus, multicellular complexity (including indigenous microbiota), and other physicochemical factors affect P. aeruginosa pathogenesis and are thus important to mimic in vitro. We highlight in vitro cell and tissue culture model systems of increasing complexity that have been used over the past 35 years to study the infectious disease process of P. aeruginosa, mainly focusing on lung models, and their respective advantages and limitations. Continued improvements of in vitro models based on our expanding knowledge of host microenvironmental factors that participate in P. aeruginosa pathogenesis will help advance fundamental understanding of pathogenic mechanisms and increase the translational potential of research findings from bench to the patient's bedside.
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Affiliation(s)
- Aurélie Crabbé
- The Biodesign Institute, Center for Infectious Diseases and Vaccinology, Arizona State University, Tempe, AZ, USA
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Tran CS, Eran Y, Ruch TR, Bryant DM, Datta A, Brakeman P, Kierbel A, Wittmann T, Metzger RJ, Mostov KE, Engel JN. Host cell polarity proteins participate in innate immunity to Pseudomonas aeruginosa infection. Cell Host Microbe 2014; 15:636-43. [PMID: 24832456 PMCID: PMC4062193 DOI: 10.1016/j.chom.2014.04.007] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2013] [Revised: 01/28/2014] [Accepted: 04/07/2014] [Indexed: 11/17/2022]
Abstract
The mucosal epithelium consists of polarized cells with distinct apical and basolateral membranes that serve as functional and physical barriers to external pathogens. The apical surface of the epithelium constitutes the first point of contact between mucosal pathogens, such as Pseudomonas aeruginosa, and their host. We observed that binding of P. aeruginosa aggregates to the apical surface of polarized cells led to the striking formation of an actin-rich membrane protrusion with inverted polarity, containing basolateral lipids and membrane components. Such protrusions were associated with a spatially localized host immune response to P. aeruginosa aggregates that required bacterial flagella and a type III secretion system apparatus. Host protrusions formed de novo underneath bacterial aggregates and involved the apical recruitment of a Par3/Par6α/aPKC/Rac1 signaling module for a robust, spatially localized host NF-κB response. Our data reveal a role for spatiotemporal epithelial polarity changes in the activation of innate immune responses.
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Affiliation(s)
- Cindy S Tran
- Division of Neonatology, Department of Pediatrics, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Yoni Eran
- Division of Infectious Disease, Department of Medicine, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Travis R Ruch
- Division of Infectious Disease, Department of Medicine, University of California, San Francisco, San Francisco, CA 94143, USA
| | - David M Bryant
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Anirban Datta
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Paul Brakeman
- Division of Pediatric Nephrology, Department of Pediatrics, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Arlinet Kierbel
- Institut Pasteur de Montevideo, Montevideo 11400, Uruguay, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Torsten Wittmann
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Ross J Metzger
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Keith E Mostov
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94143, USA; Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94143, USA; Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Joanne N Engel
- Division of Infectious Disease, Department of Medicine, University of California, San Francisco, San Francisco, CA 94143, USA; Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94143, USA.
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Leung KP, D'Arpa P, Seth AK, Geringer MR, Jett M, Xu W, Hong SJ, Galiano RD, Chen T, Mustoe TA. Dermal wound transcriptomic responses to Infection with Pseudomonas aeruginosa versus Klebsiella pneumoniae in a rabbit ear wound model. BMC Clin Pathol 2014; 14:20. [PMID: 25035691 PMCID: PMC4101837 DOI: 10.1186/1472-6890-14-20] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Accepted: 04/17/2014] [Indexed: 12/18/2022] Open
Abstract
Background Bacterial infections of wounds impair healing and worsen scarring. We hypothesized that transcriptome analysis of wounds infected with Klebsiella pneumoniae (K.p.) or Pseudomonas aeruginosa (P.a.) would indicate host-responses associated with the worse healing of P.a.- than K.p.-infected wounds. Methods Wounds created on post-operative day (POD) 0 were infected during the inflammatory phase of healing on POD3 and were harvested on POD4 for microarray and transcriptome analysis. Other wounds received topical antibiotic after infection for 24 hours to promote biofilm development, and were harvested on POD6 or POD12. Results Wounds infected for 24 hours, relative to uninfected wounds, elevated transcripts of immune-response functions characteristic of infiltrating leukocytes. But P.a.-infected wounds elevated many more transcripts and to higher levels than K.p.-infected wounds. Coincidently, suppressed transcripts of both wounds enriched into stress-response pathways, including EIF2 signaling; however, this was more extensive for P.a.-infected wounds, including many-fold more transcripts enriching in the ‘cell death’ annotation, suggesting resident cutaneous cell toxicity in response to a more damaging P.a. inflammatory milieu. The POD6 wounds were colonized with biofilm but expressed magnitudes fewer immune-response transcripts with no stress-response enrichments. However, elevated transcripts of P.a.-infected wounds were inferred to be regulated by type I interferons, similar to a network unique to P.a.-infected wounds on POD4. On POD12, transcripts that were more elevated in K.p.-infected wounds suggested healing, while transcripts more elevated in P.a.-infected wounds indicated inflammation. Conclusions An extensive inflammatory response of wounds was evident from upregulated transcripts 24 hours after infection with either bacterium, but the response was more intense for P.a.- than K.p.-infected wounds. Coincidently, more extensive down-regulated transcripts of P.a.-infected wounds indicated a stronger “integrated stress response” to the inflammatory milieu that tipped more toward cutaneous cell death. Unique to P.a.-infected wounds on POD4 and POD6 were networks inferred to be regulated by interferons, which may result from intracellular replication of P.a. These data point to specific downregulated transcripts of cells resident to the wound as well as upregulated transcripts characteristic of infiltrating leukocytes that could be useful markers of poorly healing wounds and indicators of wound-specific treatments for improving outcomes.
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Affiliation(s)
- Kai P Leung
- Microbiology Branch, US Army Dental and Trauma Research Detachment, Institute of Surgical Research, 3650 Chambers Pass, Building 3610, JBSA Fort Sam Houston, TX 78234, USA
| | - Peter D'Arpa
- Microbiology Branch, US Army Dental and Trauma Research Detachment, Institute of Surgical Research, 3650 Chambers Pass, Building 3610, JBSA Fort Sam Houston, TX 78234, USA.,Systems and Integrative Biology, US Army Center for Environmental Health Research, Fort Detrick, Frederick, MD, USA
| | - Akhil K Seth
- Division of Plastic Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Matthew R Geringer
- Division of Plastic Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Marti Jett
- Systems and Integrative Biology, US Army Center for Environmental Health Research, Fort Detrick, Frederick, MD, USA
| | - Wei Xu
- Division of Plastic Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Seok J Hong
- Division of Plastic Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Robert D Galiano
- Division of Plastic Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Tsute Chen
- The Forsyth Dental Institute, 245 First Street, Cambridge, MA 02142, USA
| | - Thomas A Mustoe
- Division of Plastic Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
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Parker D, Planet PJ, Soong G, Narechania A, Prince A. Induction of type I interferon signaling determines the relative pathogenicity of Staphylococcus aureus strains. PLoS Pathog 2014; 10:e1003951. [PMID: 24586160 PMCID: PMC3930619 DOI: 10.1371/journal.ppat.1003951] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Accepted: 01/10/2014] [Indexed: 12/31/2022] Open
Abstract
The tremendous success of S. aureus as a human pathogen has been explained primarily by its array of virulence factors that enable the organism to evade host immunity. Perhaps equally important, but less well understood, is the importance of the intensity of the host response in determining the extent of pathology induced by S. aureus infection, particularly in the pathogenesis of pneumonia. We compared the pathogenesis of infection caused by two phylogenetically and epidemiologically distinct strains of S. aureus whose behavior in humans has been well characterized. Induction of the type I IFN cascade by strain 502A, due to a NOD2-IRF5 pathway, was the major factor in causing severe pneumonia and death in a murine model of pneumonia and was associated with autolysis and release of peptidogylcan. In contrast to USA300, 502A was readily eliminated from epithelial surfaces in vitro. Nonetheless, 502A caused significantly increased tissue damage due to the organisms that were able to invade systemically and trigger type I IFN responses, and this was ameliorated in Ifnar⁻/⁻ mice. The success of USA300 to cause invasive infection appears to depend upon its resistance to eradication from epithelial surfaces, but not production of specific toxins. Our studies illustrate the important and highly variable role of type I IFN signaling within a species and suggest that targeted immunomodulation of specific innate immune signaling cascades may be useful to prevent the excessive morbidity associated with S. aureus pneumonia.
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Affiliation(s)
- Dane Parker
- Department of Pediatrics, Columbia University, New York, New York, United States of America
- * E-mail:
| | - Paul J. Planet
- Department of Pediatrics, Columbia University, New York, New York, United States of America
- Sackler Institute for Comparative Genomics, American Museum of Natural History, New York, New York, United States of America
| | - Grace Soong
- Department of Pediatrics, Columbia University, New York, New York, United States of America
| | - Apurva Narechania
- Sackler Institute for Comparative Genomics, American Museum of Natural History, New York, New York, United States of America
| | - Alice Prince
- Department of Pediatrics, Columbia University, New York, New York, United States of America
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Escherichia coli heat-stable toxin b impairs intestinal epithelial barrier function by altering tight junction proteins. Infect Immun 2013; 81:2819-27. [PMID: 23716609 DOI: 10.1128/iai.00455-13] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Escherichia coli heat-stable toxin b (STb) causes diarrhea in animals. STb binds to sulfatide, its receptor, and is then internalized. In the cytoplasm, through a cascade of events, STb triggers the opening of ion channels, allowing ion secretion and water loss and leading to diarrhea. Tight junctions (TJs) are well known for controlling paracellular traffic of ions and water by forming a physical intercellular barrier in epithelial cells, and some bacterial toxins are known to affect adversely TJs. The present study aimed at determining the effect of STb on TJs. T84 cells were treated for 24 h with purified STb and a nontoxic STb mutant (D30V). Transepithelial resistance (TER), paracellular flux marker, and confocal microscopy were used to analyze the effect of STb on TJs. Purified STb caused a significant reduction of TER parallel to an increase in paracellular permeability compared to the results seen in untreated cells or mutant D30V. The increased paracellular permeability was associated with a marked alteration of F-actin stress fibers. F-actin filament dissolution and condensation were accompanied by redistribution and/or fragmentation of ZO-1, claudin-1, and occludin. These changes were also observed following treatment of T84 cells with an 8-amino-acid peptide found in the STb sequence corresponding to a consensus sequence of Vibrio cholerae Zot toxin. These effects were not observed with a scrambled peptide or mutant D30V. Our findings indicate that STb induces epithelial barrier dysfunction through changes in TJ proteins that could contribute to diarrhea.
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48
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Regulation of Rab5 function during phagocytosis of live Pseudomonas aeruginosa in macrophages. Infect Immun 2013; 81:2426-36. [PMID: 23630954 DOI: 10.1128/iai.00387-13] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pseudomonas aeruginosa, a Gram-negative opportunistic human pathogen, is a frequent cause of severe hospital-acquired infections. Effectors produced by the type III secretion system disrupt mammalian cell membrane trafficking and signaling and are integral to the establishment of P. aeruginosa infection. One of these effectors, ExoS, ADP-ribosylates several host cell proteins, including Ras and Rab GTPases. In this study, we demonstrated that Rab5 plays a critical role during early stages of P. aeruginosa invasion of J774-Eclone macrophages. We showed that live, but not heat-inactivated, P. aeruginosa inhibited phagocytosis and that this occurred in conjunction with downregulation of Rab5 activity. Inactivation of Rab5 was dependent on ExoS ADP-ribosyltransferase activity, and in J744-Eclone cells, ExoS ADP-ribosyltransferase activity caused a more severe inhibition of phagocytosis than ExoS Rho GTPase activity. Furthermore, we found that expression of Rin1, a Rab5 guanine exchange factor, but not Rabex5 and Rap6, partially reversed the inactivation of Rab5 during invasion of live P. aeruginosa. These studies provide evidence that live P. aeruginosa cells are able to influence their rate of phagocytosis in macrophages by directly regulating activation of Rab5.
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Epithelial uptake of flagella initiates proinflammatory signaling. PLoS One 2013; 8:e59932. [PMID: 23527288 PMCID: PMC3603936 DOI: 10.1371/journal.pone.0059932] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Accepted: 02/21/2013] [Indexed: 12/31/2022] Open
Abstract
The airway epithelium serves multiple roles in the defense of the lung. Not only does it act as a physical barrier, it acts as a distal extension of the innate immune system. We investigated the role of the airway epithelium in the interaction with flagella, an important virulence factor of the pathogen Pseudomonas aeruginosa, a cause of ventilator associated pneumonia and significant morbidity and mortality in patients with cystic fibrosis. Flagella were required for transmigration across polarized airway epithelial cells and this was a direct consequence of motility, and not a signaling effect. Purified flagella did not alter the barrier properties of the epithelium but were observed to be rapidly endocytosed inside epithelial cells. Neither flagella nor intact P. aeruginosa stimulated epithelial inflammasome signaling. Flagella-dependent signaling required dynamin-based uptake as well as TLR5 and primarily led to the induction of proinflammatory (Tnf, Il6) as well as neutrophil (Cxcl1, Cxcl2, Ccl3) and macrophage (Ccl20) chemokines. Although flagella are important in invasion across the epithelial barrier their shedding in the airway lumen results in epithelial uptake and signaling that has a major role in the initial recruitment of immune cells in the lung.
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Nakashima R, Kamata Y, Nishikawa Y. Effects of Escherichia coli heat-stable enterotoxin and guanylin on the barrier integrity of intestinal epithelial T84 cells. Vet Immunol Immunopathol 2013; 152:78-81. [DOI: 10.1016/j.vetimm.2012.09.026] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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