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Kamio N, Hayata M, Tamura M, Tanaka H, Imai K. Porphyromonas gingivalis enhances pneumococcal adhesion to human alveolar epithelial cells by increasing expression of host platelet-activating factor receptor. FEBS Lett 2021; 595:1604-1612. [PMID: 33792027 DOI: 10.1002/1873-3468.14084] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 03/18/2021] [Accepted: 03/18/2021] [Indexed: 12/30/2022]
Abstract
Streptococcus pneumoniae causes pneumonia by infecting the alveolar epithelium via binding to host receptors, such as the platelet-activating factor receptor (PAFR). Although chronic periodontitis has been identified as a pneumonia risk factor, how periodontopathic bacteria cause pneumonia is not known. We found that S. pneumoniae adhered to PAFR expressed on A549 human alveolar epithelial cells stimulated by Porphyromonas gingivalis culture supernatant, and this was abrogated by a PAFR-specific inhibitor. Among the major virulence factors of P. gingivalis [lipopolysaccharide (LPS), fimbriae and gingipains (Rgps and Kgp)], PAFR expression and pneumococcal adhesion were executed in an Rgp-dependent manner. LPS and fimbriae did not induce PAFR expression. Hence, our findings suggest that P. gingivalis enhances pneumococcal adhesion to human alveoli by inducing PAFR expression and that gingipains are responsible for this.
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Affiliation(s)
- Noriaki Kamio
- Department of Microbiology, Nihon University School of Dentistry, Tokyo, Japan
| | - Mayumi Hayata
- Department of Microbiology, Nihon University School of Dentistry, Tokyo, Japan
| | - Muneaki Tamura
- Department of Microbiology, Nihon University School of Dentistry, Tokyo, Japan
| | - Hajime Tanaka
- Department of Microbiology, Nihon University School of Dentistry, Tokyo, Japan
| | - Kenichi Imai
- Department of Microbiology, Nihon University School of Dentistry, Tokyo, Japan
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Shukla SD, Walters EH, Simpson JL, Keely S, Wark PA, O'Toole RF, Hansbro PM. Hypoxia‐inducible factor and bacterial infections in chronic obstructive pulmonary disease. Respirology 2019; 25:53-63. [DOI: 10.1111/resp.13722] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 09/25/2019] [Accepted: 10/08/2019] [Indexed: 12/12/2022]
Affiliation(s)
- Shakti D. Shukla
- School of Biomedical Sciences and Pharmacy, Faculty of Health and MedicineUniversity of Newcastle Newcastle NSW Australia
- Priority Research Centre for Healthy Lungs, Hunter Medical Research InstituteUniversity of Newcastle Newcastle NSW Australia
| | - E. Haydn Walters
- School of Medicine, College of Health and MedicineUniversity of Tasmania Hobart TAS Australia
| | - Jodie L. Simpson
- Priority Research Centre for Healthy Lungs, Hunter Medical Research InstituteUniversity of Newcastle Newcastle NSW Australia
- Respiratory and Sleep Medicine, Priority Research Centre for Healthy LungsUniversity of Newcastle Newcastle NSW Australia
| | - Simon Keely
- School of Biomedical Sciences and Pharmacy, Faculty of Health and MedicineUniversity of Newcastle Newcastle NSW Australia
- Priority Research Centre for Digestive Health and Neurogastroenterology, Hunter Medical Research InstituteUniversity of Newcastle Newcastle NSW Australia
| | - Peter A.B. Wark
- Priority Research Centre for Healthy Lungs, Hunter Medical Research InstituteUniversity of Newcastle Newcastle NSW Australia
- Respiratory and Sleep Medicine, Priority Research Centre for Healthy LungsUniversity of Newcastle Newcastle NSW Australia
| | - Ronan F. O'Toole
- School of Molecular Sciences, College of Science, Health and EngineeringLa Trobe University Melbourne VIC Australia
| | - Philip M. Hansbro
- School of Biomedical Sciences and Pharmacy, Faculty of Health and MedicineUniversity of Newcastle Newcastle NSW Australia
- Priority Research Centre for Healthy Lungs, Hunter Medical Research InstituteUniversity of Newcastle Newcastle NSW Australia
- Centenary Institute and School of Life Sciences, Faculty of Science, University of Technology Sydney Sydney NSW Australia
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Phosphocholine-Modified Lipooligosaccharides of Haemophilus influenzae Inhibit ATP-Induced IL-1β Release by Pulmonary Epithelial Cells. Molecules 2018; 23:molecules23081979. [PMID: 30096783 PMCID: PMC6222299 DOI: 10.3390/molecules23081979] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 07/19/2018] [Accepted: 07/27/2018] [Indexed: 12/11/2022] Open
Abstract
Phosphocholine-modified bacterial cell wall components are virulence factors enabling immune evasion and permanent colonization of the mammalian host, by mechanisms that are poorly understood. Recently, we demonstrated that free phosphocholine (PC) and PC-modified lipooligosaccharides (PC-LOS) from Haemophilus influenzae, an opportunistic pathogen of the upper and lower airways, function as unconventional nicotinic agonists and efficiently inhibit the ATP-induced release of monocytic IL-1β. We hypothesize that H. influenzae PC-LOS exert similar effects on pulmonary epithelial cells and on the complex lung tissue. The human lung carcinoma-derived epithelial cell lines A549 and Calu-3 were primed with lipopolysaccharide from Escherichia coli followed by stimulation with ATP in the presence or absence of PC or PC-LOS or LOS devoid of PC. The involvement of nicotinic acetylcholine receptors was tested using specific antagonists. We demonstrate that PC and PC-LOS efficiently inhibit ATP-mediated IL-1β release by A549 and Calu-3 cells via nicotinic acetylcholine receptors containing subunits α7, α9, and/or α10. Primed precision-cut lung slices behaved similarly. We conclude that H. influenzae hijacked an endogenous anti-inflammatory cholinergic control mechanism of the lung to evade innate immune responses of the host. These findings may pave the way towards a host-centered antibiotic treatment of chronic airway infections with H. influenzae.
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Iovino F, Brouwer MC, van de Beek D, Molema G, Bijlsma JJE. Signalling or binding: the role of the platelet-activating factor receptor in invasive pneumococcal disease. Cell Microbiol 2013; 15:870-81. [PMID: 23444839 DOI: 10.1111/cmi.12129] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Revised: 02/17/2013] [Accepted: 02/18/2013] [Indexed: 11/29/2022]
Abstract
Streptococcus pneumoniae (the pneumococcus) is an opportunistic human pathogen, which causes serious invasive disease such as pneumonia, bacteraemia and meningitis. The interaction of the bacteria with host receptors precedes the development of invasive disease. One host receptor implicated in pneumococcal adhesion to, invasion of and ultimately translocation of cell layers is the platelet-activating factor receptor (PAFR). PAFR is a G-protein coupled receptor which binds PAF, a potent phospholipid activator involved in many leucocyte functions, platelet aggregation and inflammation. PAFR has been proposed to bind S. pneumoniae and as such facilitate adhesion to, uptake by and transcytosis of endothelial cells leading to invasive disease. However, there is a shortage of biochemical data supporting direct interaction between PAFR and the bacteria, in addition to conflicting data on its role in development of invasive pneumococcal disease (IPD). In this review, we will discuss current literature on PAFR and S. pneumoniae and other pathogens,including data concerning human PAFR genetic variation related to IPD clinical aspects, to shed light on the importance of PAFR in IPD. Clarification of the role of this receptor in IPD development has the potential to enable the development of novel therapeutic strategies for treating pneumococcal disease by interfering with the PAFR.
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Affiliation(s)
- Federico Iovino
- Department of Medical Microbiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
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5
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Microbial modulation of host immunity with the small molecule phosphorylcholine. Infect Immun 2012; 81:392-401. [PMID: 23230294 DOI: 10.1128/iai.01168-12] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
All microorganisms dependent on persistence in a host for survival rely on either hiding from or modulating host responses to infection. The small molecule phosphorylcholine, or choline phosphate (ChoP), is used for both of these purposes by a wide array of bacterial and parasitic microbes. While the mechanisms underlying ChoP acquisition and expression are diverse, a unifying theme is the use of ChoP to reduce the immune response to infection, creating an advantage for ChoP-expressing microorganisms. In this minireview, we discuss several benefits of ChoP expression during infection as well as how the immune system fights back against ChoP-expressing pathogens.
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6
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Liu M, Zhu H, Li J, Garcia CC, Feng W, Kirpotina LN, Hilmer J, Tavares LP, Layton AW, Quinn MT, Bothner B, Teixeira MM, Lei B. Group A Streptococcus secreted esterase hydrolyzes platelet-activating factor to impede neutrophil recruitment and facilitate innate immune evasion. PLoS Pathog 2012; 8:e1002624. [PMID: 22496650 PMCID: PMC3320582 DOI: 10.1371/journal.ppat.1002624] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Accepted: 02/21/2012] [Indexed: 11/19/2022] Open
Abstract
The innate immune system is the first line of host defense against invading organisms. Thus, pathogens have developed virulence mechanisms to evade the innate immune system. Here, we report a novel means for inhibition of neutrophil recruitment by Group A Streptococcus (GAS). Deletion of the secreted esterase gene (designated sse) in M1T1 GAS strains with (MGAS5005) and without (MGAS2221) a null covS mutation enhances neutrophil ingress to infection sites in the skin of mice. In trans expression of SsE in MGAS2221 reduces neutrophil recruitment and enhances skin invasion. The sse deletion mutant of MGAS5005 (ΔsseMGAS5005) is more efficiently cleared from skin than the parent strain. SsE hydrolyzes the sn-2 ester bond of platelet-activating factor (PAF), converting biologically active PAF into inactive lyso-PAF. KM and kcat of SsE for hydrolysis of 2-thio-PAF were similar to those of the human plasma PAF acetylhydrolase. Treatment of PAF with SsE abolishes the capacity of PAF to induce activation and chemotaxis of human neutrophils. More importantly, PAF receptor-deficient mice significantly reduce neutrophil infiltration to the site of ΔsseMGAS5005 infection. These findings identify the first secreted PAF acetylhydrolase of bacterial pathogens and support a novel GAS evasion mechanism that reduces phagocyte recruitment to sites of infection by inactivating PAF, providing a new paradigm for bacterial evasion of neutrophil responses. GAS is a major human pathogen causing a variety of infections, including pharyngitis and necrotizing fasciitis. GAS pathogenesis is mediated by a large array of secreted and cell-surface virulence factors. However, the functions of many GAS virulence factors are poorly understood. Recently, we reported that the esterase secreted by GAS (SsE) is a CovRS (the control of virulence two component regulatory system)-regulated protective antigen and is critical for spreading in the skin and systemic dissemination of GAS in a mouse model of necrotizing fasciitis. This report presents three major findings regarding the function and functional mechanism of SsE: 1) SsE contributes to GAS inhibition of neutrophil recruitment; 2) SsE is a potent PAF acetylhydrolase and the first secreted bacterial PAF acetylhydrolase identified so far; and 3) the PAF receptor significantly contributes to neutrophil recruitment in skin GAS infection. These findings support a novel mechanism for evasion of the innate immune system by GAS that may be relevant to other infections.
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Affiliation(s)
- Mengyao Liu
- Department of Immunology and Infectious Diseases, Montana State University, Bozeman, Montana, United States of America
| | - Hui Zhu
- Department of Immunology and Infectious Diseases, Montana State University, Bozeman, Montana, United States of America
- Department of Physiology, Harbin Medical University, Harbin, People's Republic of China
| | - Jinquan Li
- Department of Immunology and Infectious Diseases, Montana State University, Bozeman, Montana, United States of America
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, People's Republic of China
| | - Cristiana C. Garcia
- Laboratory of Immunopharmacology, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Wenchao Feng
- Department of Immunology and Infectious Diseases, Montana State University, Bozeman, Montana, United States of America
| | - Liliya N. Kirpotina
- Department of Immunology and Infectious Diseases, Montana State University, Bozeman, Montana, United States of America
| | - Jonathan Hilmer
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana, United States of America
| | - Luciana P. Tavares
- Laboratory of Immunopharmacology, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Arthur W. Layton
- Montana Veterinary Diagnostic Laboratory, Bozeman, Montana, United States of America
| | - Mark T. Quinn
- Department of Immunology and Infectious Diseases, Montana State University, Bozeman, Montana, United States of America
| | - Brian Bothner
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana, United States of America
| | - Mauro M. Teixeira
- Laboratory of Immunopharmacology, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Benfang Lei
- Department of Immunology and Infectious Diseases, Montana State University, Bozeman, Montana, United States of America
- * E-mail:
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Phosphorylcholine allows for evasion of bactericidal antibody by Haemophilus influenzae. PLoS Pathog 2012; 8:e1002521. [PMID: 22396641 PMCID: PMC3291618 DOI: 10.1371/journal.ppat.1002521] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Accepted: 12/20/2011] [Indexed: 11/19/2022] Open
Abstract
The human pathogen Haemophilus influenzae has the ability to quickly adapt to different host environments through phase variation of multiple structures on its lipooligosaccharide (LPS), including phosphorylcholine (ChoP). During colonization with H. influenzae, there is a selection for ChoP+ phase variants. In a murine model of nasopharyngeal colonization, this selection is lost in the absence of adaptive immunity. Based on previous data highlighting the importance of natural antibody in limiting H. influenzae colonization, the effect of ChoP expression on antibody binding and its bactericidal activity was investigated. Flow cytometric analysis revealed that ChoP+ phase variants had decreased binding of antibody to LPS epitopes compared to ChoP- phase variants. This difference in antibody binding correlated with increased survival of ChoP+ phase variants in the presence of antibody-dependent, complement-mediated killing. ChoP+ phase variants were also more resistant to trypsin digestion, suggesting a general effect on the physical properties of the outer membrane. Moreover, ChoP-mediated protection against antibody binding correlated with increased resilience of outer membrane integrity. Collectively, these data suggest that ChoP expression provides a selective advantage during colonization through ChoP-mediated effects on the accessibility of bactericidal antibody to the cell surface.
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Clementi CF, Murphy TF. Non-typeable Haemophilus influenzae invasion and persistence in the human respiratory tract. Front Cell Infect Microbiol 2011; 1:1. [PMID: 22919570 PMCID: PMC3417339 DOI: 10.3389/fcimb.2011.00001] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Accepted: 10/04/2011] [Indexed: 12/21/2022] Open
Abstract
Non-typeable Haemophilus influenzae (NTHI) is an opportunistic bacterial pathogen of the human respiratory tract and is a leading cause of respiratory infections in children and adults. NTHI is considered to be an extracellular pathogen, but has consistently been observed within and between human respiratory epithelial cells and macrophages, in vitro and ex vivo. Until recently, few studies have examined the internalization, trafficking, and fate of NTHI in host cells. It is important to clarify this interaction because of a possible correlation between intracellular NTHI and symptomatic infection, and because NTHI infections frequently persist and recur despite antibiotic therapy and the development of bactericidal antibodies, suggesting a possible intracellular state or reservoir for NTHI. How does NTHI enter host cells? Can NTHI survive intracellularly and, if so, for how long? Strides have been made in the identification of host receptors, signaling, endocytosis, and trafficking pathways involved in the entry and persistence of NTHI in the respiratory tract.
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Affiliation(s)
- Cara F Clementi
- Department of Microbiology and Immunology, University at Buffalo, State University of New York Buffalo, NY, USA
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Henderson B, Ward JM, Ready D. Aggregatibacter (Actinobacillus) actinomycetemcomitans: a triple A* periodontopathogen? Periodontol 2000 2010; 54:78-105. [DOI: 10.1111/j.1600-0757.2009.00331.x] [Citation(s) in RCA: 145] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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10
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van Zoelen MAD, Florquin S, Meijers JCM, de Beer R, de Vos AF, de Boer OJ, van der Poll T. Platelet-Activating Factor Receptor Contributes to Host Defense againstPseudomonas aeruginosaPneumonia but Is Not Essential for the Accompanying Inflammatory and Procoagulant Response. THE JOURNAL OF IMMUNOLOGY 2008; 180:3357-65. [DOI: 10.4049/jimmunol.180.5.3357] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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11
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Wieland CW, Stegenga ME, Florquin S, Fantuzzi G, van der Poll T. Leptin and host defense against Gram-positive and Gram-negative pneumonia in mice. Shock 2008; 25:414-9. [PMID: 16670645 DOI: 10.1097/01.shk.0000209524.12873.da] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Leptin is a pleiotrophic protein mainly produced by adipocytes that has been implicated as a link between nutritional status and immune function. Severe bacterial infection is associated with elevated plasma levels of leptin. To determine the role of leptin in the host response to bacterial pneumonia leptin deficient ob/ob mice and normal wild-type (WT) mice were intranasally infected with different doses of the Gram-positive pathogen Streptococcus (S.) pneumoniae or the Gram-negative bacterium Klebsiella (K.) pneumoniae. After infection with lower doses of either pathogen ob/ob mice displayed lower pulmonary levels of proinflammatory cytokines, in particular tumor necrosis factor-alpha and chemokines. However, after infection with a higher dose of S. pneumoniae or K. pneumoniae the lung concentrations of these inflammatory mediators did not differ between ob/ob and WT mice. In addition, the extent and severity of lung inflammation, as assessed by semi-quantitative histopathology scores, were similar in both mouse strains. Finally, leptin deficiency did not impact on the bacterial outgrowth in the lungs during either Gram-positive or Gram-negative pneumonia irrespective of the infective dose. These data suggest that although leptin may play a modest role in the regulation of inflammation during bacterial pneumonia, it does not contribute to host defense mechanisms that act to limit the outgrowth of S. pneumoniae or K. pneumoniae in the lower airways.
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Affiliation(s)
- Catharina W Wieland
- Center of Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, The Netherlands.
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12
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Wieland CW, Florquin S, van der Poll T. Interleukin 18 participates in the early inflammatory response and bacterial clearance during pneumonia caused by nontypeable Haemophilus influenzae. Infect Immun 2007; 75:5068-72. [PMID: 17664259 PMCID: PMC2044539 DOI: 10.1128/iai.00287-07] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Nontypeable Haemophilus influenzae (NTHi) is a common gram-negative respiratory pathogen. To determine the role of the proinflammatory cytokine interleukin 18 (IL-18) during NTHi pneumonia, normal wild-type (WT) and IL-18 knockout (KO) mice were intranasally infected with NTHi. IL-18 KO mice displayed a delayed clearance of NTHi from the respiratory tract, resulting in >20-fold higher bacterial loads in their lungs at 24 h after infection, preceded by a strongly attenuated pulmonary innate immune response as determined by cytokine and chemokine induction and histopathology. These data identify IL-18 as part of an adequate innate immune response during NTHi pneumonia.
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Affiliation(s)
- Catharina W Wieland
- Center of Infection and Immunity, G2-132, Academic Medical Center, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands.
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McCullers JA, Iverson AR, McKeon R, Murray PJ. The platelet activating factor receptor is not required for exacerbation of bacterial pneumonia following influenza. ACTA ACUST UNITED AC 2007; 40:11-7. [PMID: 17852951 PMCID: PMC2715993 DOI: 10.1080/00365540701477568] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Pneumonia caused by Streptococcus pneumoniae is a significant cause of morbidity and mortality during influenza virus epidemics. We had previously advanced the hypothesis that interactions of pneumococcus with the receptor for platelet activating factor (PAFR) in the lung were facilitated by antecedent influenza virus infection and play a major role in the pathogenesis of bacterial superinfections. Although influenza enhanced the adherence of pneumococci to respiratory epithelial cells in vitro, chemical or antibody-mediated blockade of the PAFR did not affect adherence. In agreement with these data, mice lacking PAFR had similar bacterial loads within the lung compartment when compared to heterozygous littermates and were not protected from secondary pneumococcal pneumonia after influenza. Lack of support for this hypothesis and the observation of enhanced inflammation during secondary pneumococcal pneumonia in mice lacking PAFR may moderate enthusiasm for treatment strategies targeting the interaction of bacteria with PAFR.
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Affiliation(s)
- Jonathan A McCullers
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee 38105-2794, USA.
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Maris NA, Florquin S, van't Veer C, de Vos AF, Buurman W, Jansen HM, van der Poll T. Inhalation of beta 2 agonists impairs the clearance of nontypable Haemophilus influenzae from the murine respiratory tract. Respir Res 2006; 7:57. [PMID: 16595015 PMCID: PMC1456968 DOI: 10.1186/1465-9921-7-57] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2006] [Accepted: 04/04/2006] [Indexed: 11/29/2022] Open
Abstract
Background Nontypable Haemophilus influenzae (NTHi) is a common bacterial pathogen causing human respiratory tract infections under permissive conditions such as chronic obstructive pulmonary disease. Inhalation of β2-receptor agonists is a widely used treatment in patients with chronic obstructive pulmonary disease. The aim of this study was to determine the effect of inhalation of β2 agonists on the host immune response to respiratory tract infection with NTHi. Methods Mouse alveolar macrophages were stimulated in vitro with NTHi in the presence or absence of the β2 receptor agonists salmeterol or salbutamol. In addition, mice received salmeterol or salbutamol by inhalation and were intranasally infected with NTHi. End points were pulmonary inflammation and bacterial loads. Results Both salmeterol and salbutamol inhibited NTHi induced tumor necrosis factor-α (TNFα) release by mouse alveolar macrophages in vitro by a β receptor dependent mechanism. In line, inhalation of either salmeterol or salbutamol was associated with a reduced early TNFα production in lungs of mice infected intranasally with NTHi, an effect that was reversed by concurrent treatment with the β blocker propranolol. The clearance of NTHi from the lungs was impaired in mice treated with salmeterol or salbutamol, an adverse effect that was prevented by propranolol and independent of the reduction in TNFα. Conclusion These data suggest that inhalation of salmeterol or salbutamol may negatively influence an effective clearance of NTHi from the airways.
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Affiliation(s)
- Nico A Maris
- Center of Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
- Center for Experimental and Molecular Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Sandrine Florquin
- Department of Pathology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Cornelis van't Veer
- Center of Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
- Center for Experimental and Molecular Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Alex F de Vos
- Center of Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
- Center for Experimental and Molecular Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Wim Buurman
- Department of Surgery, University of Maastricht, Maastricht, The Netherlands
| | - Henk M Jansen
- Department of Pulmonology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Tom van der Poll
- Center of Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
- Center for Experimental and Molecular Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
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15
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Wieland CW, Florquin S, Maris NA, Hoebe K, Beutler B, Takeda K, Akira S, van der Poll T. The MyD88-dependent, but not the MyD88-independent, pathway of TLR4 signaling is important in clearing nontypeable haemophilus influenzae from the mouse lung. THE JOURNAL OF IMMUNOLOGY 2005; 175:6042-9. [PMID: 16237099 DOI: 10.4049/jimmunol.175.9.6042] [Citation(s) in RCA: 123] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
TLRs are important for the recognition of conserved motifs expressed by invading bacteria. TLR4 is the signaling receptor for LPS, the major proinflammatory component of the Gram-negative cell wall, whereas CD14 serves as the ligand-binding part of the LPS receptor complex. Triggering of TLR4 results in the activation of two distinct intracellular pathways, one that relies on the common TLR adaptor MyD88 and one that is mediated by Toll/IL-1R domain-containing adaptor-inducing IFN-beta (TRIF). Nontypeable Haemophilus influenzae (NTHi) is a common Gram-negative respiratory pathogen that expresses both TLR4 (LPS and lipooligosaccharide) and TLR2 (lipoproteins) ligands. To determine the roles of CD14, TLR4, and TLR2 during NTHi pneumonia, the following studies were performed: 1) Alveolar macrophages from CD14 and TLR4 knockout (KO) mice were virtually unresponsive to NTHi in vitro, whereas TLR2 KO macrophages displayed a reduced NTHi responsiveness. 2) After intranasal infection with NTHi, CD14 and TLR4 KO mice showed an attenuated early inflammatory response in their lungs, which was associated with a strongly reduced clearance of NTHi from the respiratory tract; in contrast, in TLR2 KO mice, lung inflammation was unchanged, and the number of NTHi CFU was only modestly increased at the end of the 10-day observation period. 3) MyD88 KO, but not TRIF mutant mice showed an increased bacterial load in their lungs upon infection with NTHi. These data suggest that the MyD88-dependent pathway of TLR4 is important for an effective innate immune response to respiratory tract infection caused by NTHi.
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Affiliation(s)
- Catharina W Wieland
- Laboratory of Experimental Internal Medicine, University of Amsterdam, Amsterdam, The Netherlands
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