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Brown MA, Jabeen M, Bharj G, Hinks TSC. Non-typeable Haemophilus influenzae airways infection: the next treatable trait in asthma? Eur Respir Rev 2022; 31:220008. [PMID: 36130784 PMCID: PMC9724834 DOI: 10.1183/16000617.0008-2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 07/04/2022] [Indexed: 11/05/2022] Open
Abstract
Asthma is a complex, heterogeneous condition that affects over 350 million people globally. It is characterised by bronchial hyperreactivity and airways inflammation. A subset display marked airway neutrophilia, associated with worse lung function, higher morbidity and poor response to treatment. In these individuals, recent metagenomic studies have identified persistent bacterial infection, particularly with non-encapsulated strains of the Gram-negative bacterium Haemophilus influenzae. Here we review knowledge of non-typeable H. influenzae (NTHi) in the microbiology of asthma, the immune consequences of mucosal NTHi infection, various immune evasion mechanisms, and the clinical implications of NTHi infection for phenotyping and targeted therapies in neutrophilic asthma. Airway neutrophilia is associated with production of neutrophil chemokines and proinflammatory cytokines in the airways, including interleukin (IL)-1β, IL-6, IL-8, IL-12, IL-17A and tumour necrosis factor. NTHi adheres to and invades the lower respiratory tract epithelium, inducing the NLR family pyrin domain containing 3 (NLRP3) and absent in melanoma 2 (AIM2) inflammasomes. NTHi reduces expression of tight-junction proteins, impairing epithelial integrity, and can persist intracellularly. NTHi interacts with rhinoviruses synergistically via upregulation of intracellular cell adhesion molecule 1 and promotion of a neutrophilic environment, to which NTHi is adapted. We highlight the clinical relevance of this emerging pathogen and its relevance for the efficacy of long-term macrolide therapy in airways diseases, we identify important unanswered questions and we propose future directions for research.
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Affiliation(s)
- Mary Ashley Brown
- Respiratory Medicine Unit and National Institute for Health Research (NIHR) Oxford Biomedical Research Centre (BRC), Experimental Medicine Division, Nuffield Dept of Medicine, University of Oxford, Oxford, UK
| | - Maisha Jabeen
- Respiratory Medicine Unit and National Institute for Health Research (NIHR) Oxford Biomedical Research Centre (BRC), Experimental Medicine Division, Nuffield Dept of Medicine, University of Oxford, Oxford, UK
| | - Gurpreet Bharj
- Respiratory Medicine Unit and National Institute for Health Research (NIHR) Oxford Biomedical Research Centre (BRC), Experimental Medicine Division, Nuffield Dept of Medicine, University of Oxford, Oxford, UK
- Mammalian Genetics Unit, MRC Harwell Institute, Oxford, UK
| | - Timothy S C Hinks
- Respiratory Medicine Unit and National Institute for Health Research (NIHR) Oxford Biomedical Research Centre (BRC), Experimental Medicine Division, Nuffield Dept of Medicine, University of Oxford, Oxford, UK
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Leichtle A, Kurabi A, Leffers D, Därr M, Draf CS, Ryan AF, Bruchhage KL. Immunomodulation as a Protective Strategy in Chronic Otitis Media. Front Cell Infect Microbiol 2022; 12:826192. [PMID: 35433505 PMCID: PMC9005906 DOI: 10.3389/fcimb.2022.826192] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 03/03/2022] [Indexed: 12/18/2022] Open
Abstract
Introduction Major features of the pathogenesis in otitis media, the most common disease in childhood, include hyperplasia of the middle ear mucosa and infiltration by leukocytes, both of which typically resolve upon bacterial clearance via apoptosis. Activation of innate immune receptors during the inflammatory process leads to the activation of intracellular transcription factors (such as NF-κB, AP-1), which regulate both the inflammatory response and tissue growth. We investigated these leading signaling pathways in otitis media using mouse models, human samples, and human middle ear epithelial cell (HMEEC) lines for therapeutic immunomodulation. Methods A stable otitis media model in wild-type mice and immunodeficient KO-mice, as well as human tissue samples from chronic otitis media, skin from the external auditory canal and middle ear mucosa removed from patients undergoing ear surgery, were studied. Gene and protein expression of innate immune signaling molecules were evaluated using microarray, qPCR and IHC. In situ apoptosis detection determined the apoptotic rate. The influence of bacterial infection on immunomodulating molecules (TNFα, MDP, Tri-DAP, SB203580, Cycloheximide) in HMEEC was evaluated. HMEEC cells were examined after bacterial stimulation/inhibition for gene expression and cellular growth. Results Persistent mucosal hyperplasia of the middle ear mucosa in chronic otitis media resulted from gene and protein expression of inflammatory and apoptotic genes, including NODs, TNFα, Casp3 and cleaved Casp3. In clinical chronic middle ear samples, these molecules were modulated after a specific stimulation. They also induced a hyposensitive response after bacterial/NOD-/TLR-pathway double stimulation of HMEEC cells in vitro. Hence, they might be suitable targets for immunological therapeutic approaches. Conclusion Uncontrolled middle ear mucosal hyperplasia is triggered by TLRs/NLRs immunoreceptor activation of downstream inflammatory and apoptotic molecules.
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Affiliation(s)
- Anke Leichtle
- Department of Otorhinolaryngology, Head and Neck Surgery, University of Lübeck, Lübeck, Germany
- *Correspondence: Anke Leichtle,
| | - Arwa Kurabi
- Department of Otolaryngology, University of California, San Diego, San Diego, CA, United States
| | - David Leffers
- Department of Otorhinolaryngology, Head and Neck Surgery, University of Lübeck, Lübeck, Germany
| | - Markus Därr
- Department of Otorhinolaryngology, Head and Neck Surgery, University of Lübeck, Lübeck, Germany
| | - Clara Sophia Draf
- Department of Otolaryngology, University of California, San Diego, San Diego, CA, United States
| | - Allen Frederic Ryan
- Department of Otolaryngology, University of California, San Diego, San Diego, CA, United States
- Research Section, Veterans Affairs (VA) San Diego Healthcare System, La Jolla, CA, United States
| | - Karl-Ludwig Bruchhage
- Department of Otorhinolaryngology, Head and Neck Surgery, University of Lübeck, Lübeck, Germany
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Phase Variation in HMW1A Controls a Phenotypic Switch in Haemophilus influenzae Associated with Pathoadaptation during Persistent Infection. mBio 2021; 12:e0078921. [PMID: 34154422 PMCID: PMC8262952 DOI: 10.1128/mbio.00789-21] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Genetic variants arising from within-patient evolution shed light on bacterial adaptation during chronic infection. Contingency loci generate high levels of genetic variation in bacterial genomes, enabling adaptation to the stringent selective pressures exerted by the host. A significant gap in our understanding of phase-variable contingency loci is the extent of their contribution to natural infections. The human-adapted pathogen nontypeable Haemophilus influenzae (NTHi) causes persistent infections, which contribute to underlying disease progression. The phase-variable high-molecular-weight (HMW) adhesins located on the NTHi surface mediate adherence to respiratory epithelial cells and, depending on the allelic variant, can also confer high epithelial invasiveness or hyperinvasion. In this study, we characterize the dynamics of HMW-mediated hyperinvasion in living cells and identify a specific HMW binding domain shared by hyperinvasive NTHi isolates of distinct pathological origins. Moreover, we observed that HMW expression decreased over time by using a longitudinal set of persistent NTHi strains collected from chronic obstructive pulmonary disease (COPD) patients, resulting from increased numbers of simple-sequence repeats (SSRs) downstream of the functional P2hmw1A promoter, which is the one primarily driving HMW expression. Notably, the increased SSR numbers at the hmw1 promoter region also control a phenotypic switch toward lower bacterial intracellular invasion and higher biofilm formation, likely conferring adaptive advantages during chronic airway infection by NTHi. Overall, we reveal novel molecular mechanisms of NTHi pathoadaptation based on within-patient lifestyle switching controlled by phase variation.
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Continuous Microevolution Accelerates Disease Progression during Sequential Episodes of Infection. Cell Rep 2021; 30:2978-2988.e3. [PMID: 32130901 PMCID: PMC7137071 DOI: 10.1016/j.celrep.2020.02.019] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 01/24/2020] [Accepted: 02/04/2020] [Indexed: 12/04/2022] Open
Abstract
Bacteria adapt to dynamic changes in the host during chronic and recurrent infections. Bacterial microevolution is one type of adaptation that imparts a selective advantage. We hypothesize that recurrent episodes of disease promote microevolution through genetic mutations that modulate disease severity. We use a pre-clinical model of otitis media (OM) to determine the potential role for microevolution of nontypeable Haemophilus influenzae (NTHI) during sequential episodes of disease. Whole genome sequencing reveals microevolution of hemoglobin binding and lipooligosaccharide (LOS) biosynthesis genes, suggesting that adaptation of these systems is critical for infection. These OM-adapted strains promote increased biofilm formation, inflammation, stromal fibrosis, and an increased propensity to form intracellular bacterial communities (IBCs). Remarkably, IBCs remain for at least one month following clinical resolution of infection, suggesting an intracellular reservoir as a nidus for recurrent OM. Additional approaches for therapeutic design tailored to combat this burdensome disease will arise from these studies. Harrison et al. develop a sequential model of otitis media (OM) to investigate microevolution through genetic mutations that modulate disease severity. OM-adapted strains promote increased biofilm, inflammation, stromal fibrosis, and intracellular bacterial community (IBC) development. IBCs remain one month following clinical resolution of infection, suggesting a nidus for recurrent OM.
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Wu Y, Wang Y, Yang H, Li Q, Gong X, Zhang G, Zhu K. Resident bacteria contribute to opportunistic infections of the respiratory tract. PLoS Pathog 2021; 17:e1009436. [PMID: 33740012 PMCID: PMC8011790 DOI: 10.1371/journal.ppat.1009436] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 03/31/2021] [Accepted: 03/01/2021] [Indexed: 01/26/2023] Open
Abstract
Opportunistic pathogens frequently cause volatile infections in hosts with compromised immune systems or a disrupted normal microbiota. The commensalism of diverse microorganisms contributes to colonization resistance, which prevents the expansion of opportunistic pathogens. Following microbiota disruption, pathogens promptly adapt to altered niches and obtain growth advantages. Nevertheless, whether and how resident bacteria modulate the growth dynamics of invasive pathogens and the eventual outcome of such infections are still unclear. Here, we utilized birds as a model animal and observed a resident bacterium exacerbating the invasion of Avibacterium paragallinarum (previously Haemophilus paragallinarum) in the respiratory tract. We first found that negligibly abundant Staphylococcus chromogenes, rather than Staphylococcus aureus, played a dominant role in Av. paragallinarum-associated infectious coryza in poultry based on epidemic investigations and in vitro analyses. Furthermore, we determined that S. chromogenes not only directly provides the necessary nutrition factor nicotinamide adenine dinucleotide (NAD+) but also accelerates its biosynthesis and release from host cells to promote the survival and growth of Av. paragallinarum. Last, we successfully intervened in Av. paragallinarum-associated infections in animal models using antibiotics that specifically target S. chromogenes. Our findings show that opportunistic pathogens can hijack commensal bacteria to initiate infection and expansion and suggest a new paradigm to ameliorate opportunistic infections by modulating the dynamics of resident bacteria. There is an urgent need for novel intervention strategies and techniques to address the increasing dissemination of multidrug-resistant Gram-negative bacterial pathogens. More importantly, secondary bacterial infections are common in clinical practice, whereas the growth dynamics of each individual in such coinfections are still complicated and elusive. In the current study, we first identified Staphylococcus spp., especially negligibly abundant S. chromogenes, facilitating the pathogenesis of Av. paragallinarum, a Gram-negative bacterium responsible for severe and acute avian respiratory disease worldwide. Furthermore, we developed therapeutic strategies using specific antibiotics against Staphylococcus spp. to relieve clinical symptoms and reduce Av. paragallinarum-associated infections in chickens. These results show that implementation of a proper intervention strategy can prevent opportunistic infections by regulating the microbiota and elucidate the development of alternative approaches for treating Gram-negative pathogenic bacterial infections.
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Affiliation(s)
- Yifan Wu
- National Center for Veterinary Drug Safety Evaluation, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Yongqiang Wang
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Huiming Yang
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Qian Li
- National Center for Veterinary Drug Safety Evaluation, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Xiaoxia Gong
- National Center for Veterinary Drug Safety Evaluation, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Guozhong Zhang
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing, China
- * E-mail: (GZ); (KZ)
| | - Kui Zhu
- National Center for Veterinary Drug Safety Evaluation, College of Veterinary Medicine, China Agricultural University, Beijing, China
- Beijing Key Laboratory of Detection Technology for Animal-Derived Food Safety and Beijing Laboratory for Food Quality and Safety, China Agricultural University, Beijing, China
- * E-mail: (GZ); (KZ)
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Thornton RB, Hakansson A, Hood DW, Nokso-Koivisto J, Preciado D, Riesbeck K, Richmond PC, Su YC, Swords WE, Brockman KL. Panel 7 - Pathogenesis of otitis media - a review of the literature between 2015 and 2019. Int J Pediatr Otorhinolaryngol 2020; 130 Suppl 1:109838. [PMID: 31879085 PMCID: PMC7062565 DOI: 10.1016/j.ijporl.2019.109838] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
OBJECTIVE To perform a comprehensive review of the literature from July 2015 to June 2019 on the pathogenesis of otitis media. Bacteria, viruses and the role of the microbiome as well as the host response are discussed. Directions for future research are also suggested. DATA SOURCES PubMed database of the National Library of Medicine. REVIEW METHODS PubMed was searched for any papers pertaining to OM pathogenesis between July 2015 and June 2019. If in English, abstracts were assessed individually for their relevance and included in the report. Members of the panel drafted the report based on these searches and on new data presented at the 20th International Symposium on Recent Advances in Otitis Media. CONCLUSIONS The main themes that arose in OM pathogenesis were around the need for symptomatic viral infections to develop disease. Different populations potentially having different mechanisms of pathogenesis. Novel bacterial otopathogens are emerging and need to be monitored. Animal models need to continue to be developed and used to understand disease pathogenesis. IMPLICATIONS FOR PRACTICE The findings in the pathogenesis panel have several implications for both research and clinical practice. The most urgent areas appear to be to continue monitoring the emergence of novel otopathogens, and the need to develop prevention and preventative therapies that do not rely on antibiotics and protect against the development of the initial OM episode.
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Affiliation(s)
- R B Thornton
- Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, Perth, Western Australia, Australia; School of Biomedical Sciences, Faculty Health and Medical Science, University of Western Australia, Perth, Western Australia, Australia
| | - A Hakansson
- Experimental Infection Medicine, Dept. of Translational Medicine, Faculty of Medicine, Lund University, Malmö, Sweden
| | - D W Hood
- MRC Harwell Institute, Mammalian Genetics Unit, Harwell Campus, Oxfordshire, OX11 0RD, UK
| | - J Nokso-Koivisto
- Department of Otorhinolaryngology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - D Preciado
- Sheikh Zayed Center for Pediatric Surgical Innovation, Children's National Health System, Washington, DC, USA; Division of Pediatric Otolaryngology, Children's National Health System, Washington, DC, USA
| | - K Riesbeck
- Clinical Microbiology, Dept. of Translational Medicine, Faculty of Medicine, Lund University, Malmö, Sweden
| | - P C Richmond
- School of Medicine, Division of Paediatrics, Faculty Health and Medical Science, University of Western Australia, Perth, Western Australia, Australia; Perth Children's Hospital, Perth, Western Australia, Australia
| | - Y C Su
- Clinical Microbiology, Dept. of Translational Medicine, Faculty of Medicine, Lund University, Malmö, Sweden
| | - W E Swords
- Department of Microbiology and Immunology, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - K L Brockman
- Department of Microbiology & Immunology, Medical College of Wisconsin, Milwaukee, WI, USA.
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Gisselsson-Solén M, Tähtinen PA, Ryan AF, Mulay A, Kariya S, Schilder AG, Valdez TA, Brown S, Nolan RM, Hermansson A, van Ingen G, Marom T. Panel 1: Biotechnology, biomedical engineering and new models of otitis media. Int J Pediatr Otorhinolaryngol 2020; 130 Suppl 1:109833. [PMID: 31901291 PMCID: PMC7176743 DOI: 10.1016/j.ijporl.2019.109833] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To summarize recently published key articles on the topics of biomedical engineering, biotechnology and new models in relation to otitis media (OM). DATA SOURCES Electronic databases: PubMed, Ovid Medline, Cochrane Library and Clinical Evidence (BMJ Publishing). REVIEW METHODS Articles on biomedical engineering, biotechnology, material science, mechanical and animal models in OM published between May 2015 and May 2019 were identified and subjected to review. A total of 132 articles were ultimately included. RESULTS New imaging technologies for the tympanic membrane (TM) and the middle ear cavity are being developed to assess TM thickness, identify biofilms and differentiate types of middle ear effusions. Artificial intelligence (AI) has been applied to train software programs to diagnose OM with a high degree of certainty. Genetically modified mice models for OM have further investigated what predisposes some individuals to OM and consequent hearing loss. New vaccine candidates protecting against major otopathogens are being explored and developed, especially combined vaccines, targeting more than one pathogen. Transcutaneous vaccination against non-typeable Haemophilus influenzae has been successfully tried in a chinchilla model. In terms of treatment, novel technologies for trans-tympanic drug delivery are entering the clinical domain. Various growth factors and grafting materials aimed at improving healing of TM perforations show promising results in animal models. CONCLUSION New technologies and AI applications to improve the diagnosis of OM have shown promise in pre-clinical models and are gradually entering the clinical domain. So are novel vaccines and drug delivery approaches that may allow local treatment of OM. IMPLICATIONS FOR PRACTICE New diagnostic methods, potential vaccine candidates and the novel trans-tympanic drug delivery show promising results, but are not yet adapted to clinical use.
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Affiliation(s)
- Marie Gisselsson-Solén
- Department of Clinical Sciences, Division of Otorhinolaryngology, Head and Neck Surgery, Lund University Hospital, Lund, Sweden
| | - Paula A. Tähtinen
- Department of Pediatrics and Adolescent Medicine, Turku University Hospital and University of Turku, Turku, Finland
| | - Allen F. Ryan
- Division of Otolaryngology, Department of Surgery, University of California, San Diego, La Jolla, CA, USA,San Diego Veterans Affairs Healthcare System, Research Department, San Diego, CA, USA
| | - Apoorva Mulay
- The Stripp Lab, Pulmonary Department, Cedars Sinai Medical Center, Los Angeles, CA, USA
| | - Shin Kariya
- Department of Otolaryngology-Head and Neck Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Anne G.M. Schilder
- EvidENT, Ear Institute, University College London, London, UK,National Institute for Health Research University College London Biomedical Research Centre, London, UK,Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Tulio A. Valdez
- Department of Otolaryngology Head & Neck Surgery, Stanford University, Palo Alto, CA, USA
| | - Steve Brown
- MRC Harwell Institute, Mammalian Genetics Unit, Harwell Campus, Oxfordshire, UK
| | | | - Ann Hermansson
- Department of Clinical Sciences, Division of Otorhinolaryngology, Head and Neck Surgery, Lund University Hospital, Lund, Sweden
| | - Gijs van Ingen
- Department of Otolaryngology, Erasmus University Medical Center, Rotterdam, the Netherlands
| | - Tal Marom
- Department of Otolaryngology-Head and Neck Surgery, Samson Assuta Ashdod University Hospital, Faculty of Health Sciences Ben Gurion University, Ashdod, Israel.
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Rodríguez-Arce I, Al-Jubair T, Euba B, Fernández-Calvet A, Gil-Campillo C, Martí S, Törnroth-Horsefield S, Riesbeck K, Garmendia J. Moonlighting of Haemophilus influenzae heme acquisition systems contributes to the host airway-pathogen interplay in a coordinated manner. Virulence 2019; 10:315-333. [PMID: 30973092 PMCID: PMC6550540 DOI: 10.1080/21505594.2019.1596506] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 02/18/2019] [Accepted: 03/12/2019] [Indexed: 01/30/2023] Open
Abstract
Nutrient iron sequestration is the most significant form of nutritional immunity and causes bacterial pathogens to evolve strategies of host iron scavenging. Cigarette smoking contains iron particulates altering lung and systemic iron homeostasis, which may enhance colonization in the lungs of patients suffering chronic obstructive pulmonary disease (COPD) by opportunistic pathogens such as nontypeable. NTHi is a heme auxotroph, and the NTHi genome contains multiple heme acquisition systems whose role in pulmonary infection requires a global understanding. In this study, we determined the relative contribution to NTHi airway infection of the four heme-acquisition systems HxuCBA, PE, SapABCDFZ, and HbpA-DppBCDF that are located at the bacterial outer membrane or the periplasm. Our computational studies provided plausible 3D models for HbpA, SapA, PE, and HxuA interactions with heme. Generation and characterization of single mutants in the hxuCBA, hpe, sapA, and hbpA genes provided evidence for participation in heme binding-storage and inter-bacterial donation. The hxuA, sapA, hbpA, and hpe genes showed differential expression and responded to heme. Moreover, HxuCBA, PE, SapABCDFZ, and HbpA-DppBCDF presented moonlighting properties related to resistance to antimicrobial peptides or glutathione import, together likely contributing to the NTHi-host airway interplay, as observed upon cultured airway epithelia and in vivo lung infection. The observed multi-functionality was shown to be system-specific, thus limiting redundancy. Together, we provide evidence for heme uptake systems as bacterial factors that act in a coordinated and multi-functional manner to subvert nutritional- and other sources of host innate immunity during NTHi airway infection.
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Affiliation(s)
| | - Tamim Al-Jubair
- Clinical Microbiology, Department of Translational Medicine, Faculty of Medicine, Lund University, Malmö, Sweden
- Department of Biomedical Sciences, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Begoña Euba
- Instituto de Agrobiotecnología, CSIC-Gobierno, Navarra, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Madrid, Spain
| | | | | | - Sara Martí
- Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Madrid, Spain
- Departamento Microbiología, Hospital Universitari Bellvitge, University of Barcelona, IDIBELL, Barcelona, Spain
| | - Susanna Törnroth-Horsefield
- Department of Biochemistry and Structural Biology, Center for Molecular Protein Science, Lund University, Lund, Sweden
| | - Kristian Riesbeck
- Clinical Microbiology, Department of Translational Medicine, Faculty of Medicine, Lund University, Malmö, Sweden
| | - Junkal Garmendia
- Instituto de Agrobiotecnología, CSIC-Gobierno, Navarra, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Madrid, Spain
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Discovery and Contribution of Nontypeable Haemophilus influenzae NTHI1441 to Human Respiratory Epithelial Cell Invasion. Infect Immun 2019; 87:IAI.00462-19. [PMID: 31427451 DOI: 10.1128/iai.00462-19] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 07/25/2019] [Indexed: 11/20/2022] Open
Abstract
Nontypeable Haemophilus influenzae (NTHi) is the primary cause of bacterially induced acute exacerbations of chronic obstructive pulmonary disease (COPD). NTHi adheres to and invades host respiratory epithelial cells as a means to persist in the lower airways of adults with COPD. Therefore, we mined the genomes of NTHi strains isolated from the airways of adults with COPD to identify novel proteins to investigate their role in adherence and invasion of human respiratory epithelial cells. An isogenic knockout mutant of the open reading frame NTHI1441 showed a 76.6% ± 5.5% reduction in invasion of human bronchial and alveolar epithelial cells at 1, 3, and 6 h postinfection. Decreased invasion of the NTHI1441 mutant was independent of either intracellular survival or adherence to cells. NTHI1441 is conserved among NTHi genomes. Results of whole-bacterial-cell enzyme-linked immunosorbent assay (ELISA) and flow cytometry experiments identified that NTHI1441 has epitopes expressed on the bacterial cell surface. Adults with COPD develop increased serum IgG against NTHI1441 after experiencing an exacerbation with NTHi. This study reveals NTHI1441 as a novel NTHi virulence factor expressed during infection of the COPD lower airways that contributes to invasion of host respiratory epithelial cells. The role in host cell invasion, conservation among strains, and expression of surface-exposed epitopes suggest that NTHI1441 is a potential target for preventative and therapeutic interventions for disease caused by NTHi.
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