1
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Atack JM, Brockman KL, Bakaletz LO, Jennings MP. High-depth RNA-Seq data sets to investigate the differences in gene expression mediated by phasevarions in non-typeable Haemophilus influenzae. Microbiol Resour Announc 2023; 12:e0078523. [PMID: 37991358 PMCID: PMC10720539 DOI: 10.1128/mra.00785-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Accepted: 10/16/2023] [Indexed: 11/23/2023] Open
Abstract
Non-typeable Haemophilus influenzae (NTHi) is a major bacterial pathogen of the human airway. We report high-depth coverage RNA-Seq data from prototype NTHi strains 723 and R2866, encoding two of the most common phase-variable ModA alleles found in NTHi strains, ModA2 and ModA10, respectively.
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Affiliation(s)
- John M. Atack
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia
- School of Environment and Science, Griffith University, Gold Coast, Queensland, Australia
| | - Kenneth L. Brockman
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Lauren O. Bakaletz
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children’s Hospital, Columbus, Ohio, USA
- The Ohio State University College of Medicine, Columbus, Ohio, USA
| | - Michael P. Jennings
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia
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2
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Wills BM, Garai P, Dickinson Q, Meyer JG, Brockman KL. Phase variable acetylation of lipooligosaccharide modifies antibody production and opsonophagocytic killing of non-typeable Haemophilus influenzae. iScience 2023; 26:107785. [PMID: 37727736 PMCID: PMC10505976 DOI: 10.1016/j.isci.2023.107785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 05/12/2023] [Accepted: 08/28/2023] [Indexed: 09/21/2023] Open
Abstract
Non-typeable Haemophilus influenzae (NTHi) causes millions of infections each year. Though it is primarily known to cause otitis media, recent studies have shown NTHi is emerging as a primary pathogen for invasive infection, prompting the need for new vaccines and treatments. Lipooligosaccharide (LOS) has been identified as a potential vaccine candidate due to its immunogenic nature and outer membrane localization. Yet, phase variable expression of genes involved in LOS synthesis has complicated vaccine development. In this study, we used a chinchilla model of otitis media to investigate how phase variation of oafA, a gene involved in LOS biosynthesis, affects antibody production in response to infection. We found that acetylation of LOS by OafA inhibited production of LOS-specific antibodies during infection and that NTHi expressing acetylated LOS were subsequently better protected against opsonophagocytic killing. These findings highlight the importance of understanding how phase variable modifications might affect vaccine efficacy and success.
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Affiliation(s)
- Brandon M. Wills
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Preeti Garai
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Quinn Dickinson
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Jesse G. Meyer
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Kenneth L. Brockman
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
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3
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Wills BM, Garai P, Riegert MO, Sanchez FT, Pickrum AM, Frank DW, Brockman KL. Identification of Virulence Factors Involved in a Murine Model of Severe Achromobacter xylosoxidans Infection. Infect Immun 2023:e0003723. [PMID: 37255468 DOI: 10.1128/iai.00037-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023] Open
Abstract
Achromobacter xylosoxidans (Ax) is an opportunistic pathogen and causative agent of numerous infections particularly in immunocompromised individuals with increasing prevalence in cystic fibrosis (CF). To date, investigations have focused on the clinical epidemiology and genomic comparisons of Ax isolates, yet little is known about disease pathology or the role that specific virulence factors play in tissue invasion or damage. Here, we model an acute Ax lung infection in immunocompetent C57BL/6 mice and immunocompromised CF mice, revealing a link between in vitro cytotoxicity and disease in an intact host. Mice were intratracheally challenged with sublethal doses of a cytotoxic (GN050) or invasive (GN008) strain of Ax. Bacterial burden, immune cell populations, and inflammatory markers in bronchoalveolar lavage fluid and lung homogenates were measured at different time points to assess disease severity. CF mice had a similar but delayed immune response toward both Ax strains compared to C57BL/6J mice. GN050 caused more severe disease and higher mortality which correlated with greater bacterial burden and increased proinflammatory responses in both mouse models. In agreement with the cytotoxicity of GN050 toward macrophages in vitro, mice challenged with GN050 had fewer macrophages. Mutants with transposon insertions in predicted virulence factors of GN050 showed that disease severity depended on the type III secretion system, Vi capsule, antisigma-E factor, and partially on the ArtA adhesin. The development of an acute infection model provides an essential tool to better understand the infectivity of diverse Ax isolates and enable improved identification of virulence factors important to bacterial persistence and disease.
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Affiliation(s)
- Brandon M Wills
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Preeti Garai
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Molly O Riegert
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Felix T Sanchez
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Adam M Pickrum
- Department of Microbiology, New York University Grossman School of Medicine, New York, New York, USA
| | - Dara W Frank
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Kenneth L Brockman
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
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4
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Garai P, Atack JM, Wills BM, Jennings MP, Bakaletz LO, Brockman KL. Adherence of Nontypeable Haemophilus influenzae to Cells and Substrates of the Airway Is Differentially Regulated by Individual ModA Phasevarions. Microbiol Spectr 2023; 11:e0409322. [PMID: 36511712 PMCID: PMC9927368 DOI: 10.1128/spectrum.04093-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 11/28/2022] [Indexed: 12/15/2022] Open
Abstract
Adherence of nontypeable Haemophilus influenzae (NTHi) to the host airway is an essential initial step for asymptomatic colonization of the nasopharynx, as well as development of disease. NTHi relies on strict regulation of multiple adhesins for adherence to host substrates encountered in the airway. NTHi encode a phase-variable cytoplasmic DNA methyltransferase, ModA, that regulates expression of multiple genes; a phasevarion (phase-variable regulon). Multiple modA alleles are present in NTHi, in which different alleles methylate a different DNA target, and each controls a different set of genes. However, the role of ModA phasevarions in regulating adherence of NTHi to the host airway is not well understood. This study therefore sought to investigate the role of four of the most prevalent ModA phasevarions in the regulation of adherence of NTHi to multiple substrates of the airway. Four clinical isolates of NTHi with unique modA alleles were tested in this study. The adherence of NTHi to mucus, middle ear epithelial cells, and vitronectin was regulated in a substrate-specific manner that was dependent on the ModA allele encoded. The adhesins Protein E and P4 were found to contribute to the ModA-regulated adherence of NTHi to distinct substrates. A better understanding of substrate-specific regulation of NTHi adherence by ModA phasevarions will allow identification of NTHi populations present at the site of disease within the airway and facilitate more directed development of vaccines and therapeutics. IMPORTANCE Nontypeable Haemophilus influenzae (NTHi) is a predominant pathogen of the human airway that causes respiratory infections such as otitis media (OM) and exacerbations in the lungs of patients suffering from chronic obstructive pulmonary disease (COPD). Due to the lack of a licensed vaccine against NTHi and the emergence of antibiotic-resistant strains, it is extremely challenging to target NTHi for treatment. NTHi adhesins are considered potential candidates for vaccines or other therapeutic approaches. The ModA phasevarions of NTHi play a role in the rapid adaptation of the pathogen to different environmental stress conditions. This study addressed the role of ModA phasevarions in the regulation of adherence of NTHi to specific host substrates found within the respiratory tract. The findings of this study improve our understanding of regulation of adherence of NTHi to the airway, which may further be used to enhance the potential of adhesins as vaccine antigens and therapeutic targets against NTHi.
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Affiliation(s)
- Preeti Garai
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - John M. Atack
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia
- School of Environment and Science, Griffith University, Gold Coast, Queensland, Australia
| | - Brandon M. Wills
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Michael P. Jennings
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia
| | - Lauren O. Bakaletz
- Abigail Wexner Research Institute, Center for Microbial Pathogenesis, Nationwide Children’s Hospital, Columbus, Ohio, USA
- College of Medicine, Department of Pediatrics, The Ohio State University, Columbus, Ohio, USA
| | - Kenneth L. Brockman
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
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5
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Robledo-Avila FH, Ruiz-Rosado JDD, Partida-Sanchez S, Brockman KL. A Bacterial Epigenetic Switch in Non-typeable Haemophilus influenzae Modifies Host Immune Response During Otitis Media. Front Cell Infect Microbiol 2020; 10:512743. [PMID: 33194779 PMCID: PMC7644868 DOI: 10.3389/fcimb.2020.512743] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2019] [Accepted: 09/15/2020] [Indexed: 01/15/2023] Open
Abstract
Non-typeable Haemophilus influenzae (NTHi) causes multiple diseases of the human airway and is a predominant bacterial pathogen of acute otitis media and otitis media in which treatment fails. NTHi utilizes a system of phase variable epigenetic regulation, termed the phasevarion, to facilitate adaptation and survival within multiple sites of the human host. The NTHi phasevarion influences numerous disease-relevant phenotypes such as biofilm formation, antibiotic resistance, and opsonization. We have previously identified an advantageous selection for a specific phasevarion status, which significantly affects severity and chronicity of experimental otitis media. In this study, we utilized pure cultures of NTHi variants in which modA was either locked ON or locked OFF, and thus modA was unable to phase vary. These locked variants were used to assess the progression of experimental otitis media and define the specific immune response induced by each subpopulation. Although the initial disease caused by each subpopulation was similar, the immune response elicited by each subpopulation was unique. The modA2 OFF variant induced significantly greater activation of macrophages both in vitro and within the middle ear during disease. In contrast, the modA2 ON variant induced a greater neutrophil extracellular trap response, which led to greater killing of the modA2 ON variant. These data suggest that not only does the NTHi phasevarion facilitate adaptation, but also allows the bacteria to alter immune responses during disease. Understanding these complex bacterial-host interactions and the regulation of bacterial factors responsible is critical to the development of better diagnostic, treatment, and preventative strategies for these bacterial pathogens.
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Affiliation(s)
- Frank H Robledo-Avila
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH, United States
| | - Juan de Dios Ruiz-Rosado
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH, United States.,Department of Biochemistry and Immunology, National Technological Institute of Oaxaca, Oaxaca, Mexico
| | - Santiago Partida-Sanchez
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH, United States.,Department of Pediatrics, College of Medicine, The Ohio State University, Columbus, OH, United States
| | - Kenneth L Brockman
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH, United States.,Department of Pediatrics, College of Medicine, The Ohio State University, Columbus, OH, United States.,Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, WI, United States
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6
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Robledo-Avila FH, de Dios Ruiz Rosado J, Brockman KL, Partida-Sanchez S. The TRPM2 ion channel regulates the inflammatory response of neutrophils during Listeria monocytogenes infection. The Journal of Immunology 2020. [DOI: 10.4049/jimmunol.204.supp.148.23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Abstract
Calcium signaling is required for most antimicrobial functions of neutrophils. The transient receptor potential melastatin-2 (TRPM2) cation channel has been proposed to play important roles in modulating calcium mobilization, cell migration and oxidative stress in neutrophils. However, the precise mechanism by which TRPM2 activation may exert a pro- or anti-inflammatory function remains unclear. In this study, we used a mouse model of Listeria monocytogenes infection to define the role of TRPM2 in the regulation of neutrophils’ function. We found that infected Trpm2−/− mice were associated with high bacterial burden in spleen and liver indicating increased susceptibility to Listeria infection. Pronounced migration rates of neutrophils and monocytes to the liver and spleen characterized the inflammatory response to Listeria during the first 18h. In the Trpm2−/− mice, the acute phase infection resulted in septic shock, defined by increased serum levels of TNF-α, IL-6, and IL-10, but no decreased levels of IFN-γ or IL-12. Furthermore, depletion of neutrophils demonstrated the critical role of these cells in regulating acute inflammation by conferring resistance of Trpm2−/− mice to Listeria infection. Gene expression and inflammatory cytokine analyses of infected tissues further confirmed the hyperinflammatory profile of Trpm2−/− neutrophils. Finally, the increased inflammatory properties of Trpm2−/− neutrophils correlated with cellular calcium overloading and potentiated membrane depolarization, in response to Listeria infection. In conclusion, our findings suggest that TRPM2 channel plays critical roles in the regulation of the inflammatory properties of neutrophils during Listeria monocytogenes infection.
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7
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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8
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Robledo-Avila FH, Ruiz-Rosado JDD, Brockman KL, Partida-Sánchez S. The TRPM2 Ion Channel Regulates Inflammatory Functions of Neutrophils During Listeria monocytogenes Infection. Front Immunol 2020; 11:97. [PMID: 32117251 PMCID: PMC7010865 DOI: 10.3389/fimmu.2020.00097] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 01/14/2020] [Indexed: 12/23/2022] Open
Abstract
During infection, phagocytic cells pursue homeostasis in the host via multiple mechanisms that control microbial invasion. Neutrophils respond to infection by exerting a variety of cellular processes, including chemotaxis, activation, phagocytosis, degranulation and the generation of reactive oxygen species (ROS). Calcium (Ca2+) signaling and the activation of specific Ca2+ channels are required for most antimicrobial effector functions of neutrophils. The transient receptor potential melastatin-2 (TRPM2) cation channel has been proposed to play important roles in modulating Ca2+ mobilization and oxidative stress in neutrophils. In the present study, we use a mouse model of Listeria monocytogenes infection to define the role of TRPM2 in the regulation of neutrophils' functions during infection. We show that the susceptibility of Trpm2−/− mice to L. monocytogenes infection is characterized by increased migration rates of neutrophils and monocytes to the liver and spleen in the first 24 h. During the acute phase of L. monocytogenes infection, Trpm2−/− mice developed septic shock, characterized by increased serum levels of TNF-α, IL-6, and IL-10. Furthermore, in vivo depletion of neutrophils demonstrated a critical role of these immune cells in regulating acute inflammation in Trpm2−/− infected mice. Gene expression and inflammatory cytokine analyses of infected tissues further confirmed the hyperinflammatory profile of Trpm2−/− neutrophils. Finally, the increased inflammatory properties of Trpm2−/− neutrophils correlated with the dysregulated cytoplasmic concentration of Ca2+ and potentiated membrane depolarization, in response to L. monocytogenes. In conclusion, our findings suggest that the TRPM2 channel plays critical functional roles in regulating the inflammatory properties of neutrophils and preventing tissue damage during Listeria infection.
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Affiliation(s)
- Frank H Robledo-Avila
- Center for Microbial Pathogenesis, The Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH, United States
| | - Juan de Dios Ruiz-Rosado
- Center for Microbial Pathogenesis, The Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH, United States
| | - Kenneth L Brockman
- Center for Microbial Pathogenesis, The Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH, United States.,Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Santiago Partida-Sánchez
- Center for Microbial Pathogenesis, The Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH, United States.,Department of Pediatrics, College of Medicine, The Ohio State University, Columbus, OH, United States
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9
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Atack JM, Day CJ, Poole J, Brockman KL, Bakaletz LO, Barenkamp SJ, Jennings MP. The HMW2 adhesin of non-typeable Haemophilus influenzae is a human-adapted lectin that mediates high-affinity binding to 2-6 linked N-acetylneuraminic acid glycans. Biochem Biophys Res Commun 2018; 503:1103-1107. [PMID: 29944882 PMCID: PMC6095747 DOI: 10.1016/j.bbrc.2018.06.126] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Accepted: 06/21/2018] [Indexed: 01/02/2023]
Abstract
Non-typeable Haemophilus influenzae (NTHi) is a human-adapted bacterial pathogen, responsible for infections of the human respiratory tract. This pathogen expresses a range of adhesins that mediate binding to host cells. Most NTHi strains can express the related adhesins HMW1 and HMW2. Expression of HMW proteins is phase-variable: changes in the length of simple-sequence repeats located in the encoding genes promoter regions results in changes in expression levels of these adhesins. HMW expression is also controlled by epigenetic regulation. HMW1 has been previously demonstrated to bind α 2-3 sialyl-lactosamine, but affinity of this interaction has not been investigated. The host receptor(s) for HMW2 is currently unknown. We hypothesized that host glycans may act as receptors for HMW2-mediated adherence. We examined the glycan-binding activity of HMW2 using glycan arrays and Surface Plasmon Resonance (SPR). These studies demonstrate that HMW2 binds 2-6 linked N-acetylneuraminic acid with high affinity. HMW2 did not bind glycan structures containing the non-human form of sialic acid, N-glycolylneuraminic acid. Thus, the specificity of HMW1 and HMW2 have complementary lectin activities that may allow NTHi distinct niches in the human host.
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Affiliation(s)
- John M Atack
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, 4222, Australia
| | - Christopher J Day
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, 4222, Australia
| | - Jessica Poole
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, 4222, Australia
| | - Kenneth L Brockman
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, The Ohio State University College of Medicine, Columbus, OH, 43205, USA
| | - Lauren O Bakaletz
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, The Ohio State University College of Medicine, Columbus, OH, 43205, USA
| | - Stephen J Barenkamp
- Department of Pediatrics, Saint Louis University School of Medicine, The Pediatric Research Institute, Cardinal Glennon Children's Hospital, Saint Louis, MO, 63104, USA
| | - Michael P Jennings
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, 4222, Australia.
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10
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Robledo-Avila FH, Ruiz-Rosado JDD, Brockman KL, Kopp BT, Amer AO, McCoy K, Bakaletz LO, Partida-Sanchez S. Dysregulated Calcium Homeostasis in Cystic Fibrosis Neutrophils Leads to Deficient Antimicrobial Responses. J Immunol 2018; 201:2016-2027. [PMID: 30120123 DOI: 10.4049/jimmunol.1800076] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 07/23/2018] [Indexed: 12/21/2022]
Abstract
Cystic fibrosis (CF), one of the most common human genetic diseases worldwide, is caused by a defect in the CF transmembrane conductance regulator (CFTR). Patients with CF are highly susceptible to infections caused by opportunistic pathogens (including Burkholderia cenocepacia), which induce excessive lung inflammation and lead to the eventual loss of pulmonary function. Abundant neutrophil recruitment into the lung is a key characteristic of bacterial infections in CF patients. In response to infection, inflammatory neutrophils release reactive oxygen species and toxic proteins, leading to aggravated lung tissue damage in patients with CF. The present study shows a defect in reactive oxygen species production by mouse Cftr-/- , human F508del-CFTR, and CF neutrophils; this results in reduced antimicrobial activity against B. cenocepacia Furthermore, dysregulated Ca2+ homeostasis led to increased intracellular concentrations of Ca2+ that correlated with significantly diminished NADPH oxidase response and impaired secretion of neutrophil extracellular traps in human CF neutrophils. Functionally deficient human CF neutrophils recovered their antimicrobial killing capacity following treatment with pharmacological inhibitors of Ca2+ channels and CFTR channel potentiators. Our findings suggest that regulation of neutrophil Ca2+ homeostasis (via CFTR potentiation or by the regulation of Ca2+ channels) can be used as a new therapeutic approach for reestablishing immune function in patients with CF.
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Affiliation(s)
- Frank H Robledo-Avila
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, Columbus, OH 43205
| | - Juan de Dios Ruiz-Rosado
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, Columbus, OH 43205
| | - Kenneth L Brockman
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, Columbus, OH 43205
| | - Benjamin T Kopp
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, Columbus, OH 43205.,Section of Pediatric Pulmonology, Nationwide Children's Hospital, Columbus, OH 43205
| | - Amal O Amer
- Department of Microbial Infection and Immunity, College of Medicine, The Ohio State University, Columbus, OH 43210; and
| | - Karen McCoy
- Section of Pediatric Pulmonology, Nationwide Children's Hospital, Columbus, OH 43205.,Department of Pediatrics, College of Medicine, The Ohio State University, Columbus, OH 43210
| | - Lauren O Bakaletz
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, Columbus, OH 43205.,Department of Pediatrics, College of Medicine, The Ohio State University, Columbus, OH 43210
| | - Santiago Partida-Sanchez
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, Columbus, OH 43205; .,Department of Pediatrics, College of Medicine, The Ohio State University, Columbus, OH 43210
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11
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Novotny LA, Brockman KL, Mokrzan EM, Jurcisek JA, Bakaletz LO. Biofilm biology and vaccine strategies for otitis media due to nontypeable Haemophilus influenzae. J PEDIAT INF DIS-GER 2018; 14:69-77. [PMID: 30853830 DOI: 10.1055/s-0038-1660818] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Otitis media (OM) is one of the most common diseases of childhood, and nontypeable Haemophilus influenzae (NTHI) is the predominant causative agent of chronic and recurrent OM, as well as OM for which treatment has failed. Moreover, NTHI is now as important a causative agent of acute OM as the pneumococcus. NTHI colonizes the human nasopharynx asymptomatically. However, upon perturbation of the innate and physical defenses of the airway by upper respiratory tract viral infection, NTHI can replicate, ascend the Eustachian tube, gain access to the normally sterile middle ear space, and cause disease. Bacterial biofilms within the middle ear, including those formed by NTHI, contribute to the chronic and recurrent nature of this disease. These multicomponent structures are highly resistant to clearance by host defenses and elimination by traditional antimicrobial therapies. Herein, we review several strategies utilized by NTHI in order to persist within the human host and interventions currently under investigation to prevent and/or resolve NTHI-induced diseases of the middle ear and uppermost airway.
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Affiliation(s)
- Laura A Novotny
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital and The Ohio State University College of Medicine, Columbus, OH, USA
| | - Kenneth L Brockman
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital and The Ohio State University College of Medicine, Columbus, OH, USA
| | - Elaine M Mokrzan
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital and The Ohio State University College of Medicine, Columbus, OH, USA
| | - Joseph A Jurcisek
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital and The Ohio State University College of Medicine, Columbus, OH, USA
| | - Lauren O Bakaletz
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital and The Ohio State University College of Medicine, Columbus, OH, USA
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Brockman KL, Branstool MT, Atack JM, Robledo-Avila F, Partida-Sanchez S, Jennings MP, Bakaletz LO. The ModA2 Phasevarion of nontypeable Haemophilus influenzae Regulates Resistance to Oxidative Stress and Killing by Human Neutrophils. Sci Rep 2017; 7:3161. [PMID: 28600561 PMCID: PMC5466613 DOI: 10.1038/s41598-017-03552-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 05/02/2017] [Indexed: 11/22/2022] Open
Abstract
Nontypeable Haemophilus influenzae (NTHI) is the causative agent of multiple respiratory tract infections. Several human pathogens, including NTHI, possess a novel genetic system, termed the phasevarion, which mediates a rapid and reversible change in the expression of many genes throughout the chromosome. This occurs by phase variation of a single gene (modA) that encodes a DNA methyltransferase and results in two phenotypically distinct subpopulations, ON and OFF. NTHI encounters many pressures within the various microenvironments of its human host as the disease course evolves from one of asymptomatic nasopharyngeal carriage to overt disease. These include oxidative stresses, which are present throughout the respiratory tract. To persist in the human nasopharynx and as a pathogen throughout the airways, NTHI must be able to mitigate toxic levels of oxidative stress. Here we show that expression of ModA2, modA2 ON status, resulted in increased sensitivity to oxidative stress. Furthermore, the modA2 ON status resulted in decreased resistance to neutrophil-mediated killing, which resulted in selection for the modA2 OFF subpopulation in an ex vivo survival assay. These findings highlight the importance of the ModA2 phasevarion in adaptation to innate host defences and reveal an additional microenvironmental pressure that selected for a specific ModA2 subpopulation.
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Affiliation(s)
- Kenneth L Brockman
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital and The Ohio State University College of Medicine, Columbus, Ohio, 43205, USA
| | - M Taylor Branstool
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital and The Ohio State University College of Medicine, Columbus, Ohio, 43205, USA
| | - John M Atack
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, 4222, Australia
| | - Frank Robledo-Avila
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital and The Ohio State University College of Medicine, Columbus, Ohio, 43205, USA
| | - Santiago Partida-Sanchez
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital and The Ohio State University College of Medicine, Columbus, Ohio, 43205, USA
| | - Michael P Jennings
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, 4222, Australia
| | - Lauren O Bakaletz
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital and The Ohio State University College of Medicine, Columbus, Ohio, 43205, USA.
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Brockman KL, Jurcisek JA, Atack JM, Srikhanta YN, Jennings MP, Bakaletz LO. ModA2 Phasevarion Switching in Nontypeable Haemophilus influenzae Increases the Severity of Experimental Otitis Media. J Infect Dis 2016; 214:817-24. [PMID: 27288538 DOI: 10.1093/infdis/jiw243] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Accepted: 05/31/2016] [Indexed: 12/11/2022] Open
Abstract
Several human-adapted bacterial pathogens use a phasevarion (ie, a phase-variable regulon) to rapidly and reversibly regulate the expression of many genes, which include known virulence factors, yet the influence of phasevarion-mediated regulation in pathogenesis remains poorly understood. Here we examine the impact of the nontypeable Haemophilus influenzae (NTHI) ModA2 phasevarion on pathogenesis and disease severity in a chinchilla model of experimental otitis media. Chinchillas were challenged with NTHI variant populations that were either inoculated ON and remained ON, inoculated OFF and shifted ON, or inoculated OFF and remained OFF, within the middle ear. We show that populations that shift from OFF to ON within the middle ear induce significantly greater disease severity than populations that are unable to shift. These observations support the importance of phasevarion switching in NTHI pathogenesis and the necessity to considered phasevarion regulation when developing methods to treat and prevent infection.
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Affiliation(s)
- Kenneth L Brockman
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital The Ohio State University College of Medicine, Columbus, Ohio
| | - Joseph A Jurcisek
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital The Ohio State University College of Medicine, Columbus, Ohio
| | - John M Atack
- Institute for Glycomics, Griffith University, Gold Coast, Australia
| | | | | | - Lauren O Bakaletz
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital The Ohio State University College of Medicine, Columbus, Ohio
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