Pseudomonas expression of an oxygen sensing prolyl hydroxylase homologue regulates neutrophil host responses in vitro and in vivo

Dickinson, Rebecca S. and Murphy, Fiona and Doherty, Catherine and Williams, Sam and Mirchandani, Ananda and Willson, Joseph and Scotti, John S. and Preston, Gail and Schofield, Christopher J. and Whyte, Moira K.B. and Walmsley, Sarah R. (2017) Pseudomonas expression of an oxygen sensing prolyl hydroxylase homologue regulates neutrophil host responses in vitro and in vivo. Wellcome Open Research, 2 (104). pp. 1-15. A4. ISSN 2398-502X (https://doi.org/10.12688/wellcomeopenres.12871.1)

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Abstract

Background: Pseudomonas species are adapted to evade innate immune responses and can persist at sites of relative tissue hypoxia, including the mucus-plugged airways of patients with cystic fibrosis and bronchiectasis. The ability of these bacteria to directly sense and respond to changes in local oxygen availability is in part consequent upon expression of the 2-oxoglutarate oxygenase, Pseudomonas prolyl hydroxylase (PPHD), which acts on elongation factor Tu (EF-Tu), and is homologous with the human hypoxia inducible factor (HIF) prolyl hydroxylases. We report that PPHD expression regulates the neutrophil response to acute pseudomonal infection. Methods: In vitro co-culture experiments were performed with human neutrophils and PPHD-deficient and wild-type bacteria and supernatants, with viable neutrophil counts determined by flow cytometry. In vivo consequences of infection with PPHD deficient P. aeruginosa were determined in an acute pneumonia mouse model following intra-tracheal challenge. Results: Supernatants of PPHD-deficient bacterial cultures contained higher concentrations of the phenazine exotoxin pyocyanin and induced greater acceleration of neutrophil apoptosis than wild-type PAO1 supernatants in vitro. In vivo infection with PPHD mutants compared to wild-type PAO1 controls resulted in increased levels of neutrophil apoptosis and impaired control of infection, with higher numbers of P. aeruginosa recovered from the lungs of mice infected with the PPHD-deficient strain. This resulted in an overall increase in mortality in mice infected with the PPHD-deficient strain. Conclusions: Our data show that Pseudomonas expression of its prolyl hydroxylase influences the outcome of host-pathogen interactions in vitro and in vivo, demonstrating the importance of considering how both host and pathogen adaptations to hypoxia together define outcomes of infection. Given that inhibitors for the HIF prolyl hydroxylases are in late stage trials for the treatment of anaemia and that the active sites of PPHD and human HIF prolyl hydroxylases are closely related, the results are of current clinical interest.

  • Item type:Article
    ID code:86562
    Dates:
    Date
    Event
    22 November 2017
    Published
    22 November 2017
    Accepted
    26 October 2017
    Submitted
    Notes:Funding Information: This study was supported by the Wellcome Trust [098516], a Senior Clinical Fellowship award to SRW, and [110086], a Postdoctoral Fellowship to AM. CJS thanks the Wellcome Trust and British Heart Foundation for support. Publisher Copyright: Copyright: © 2017 Dickinson RS et al. Dickinson RS, Murphy F, Doherty C et al. Pseudomonas expression of an oxygen sensing prolyl hydroxylase homologue regulates neutrophil host responses in vitro and in vivo [version 1; peer review: 3 approved, 1 approved with reservations]. Wellcome Open Res 2017, 2:104 (https://doi.org/10.12688/wellcomeopenres.12871.1)
    Subjects:Medicine > Pharmacy and materia medica
    Science > Microbiology
    Department:Faculty of Science > Strathclyde Institute of Pharmacy and Biomedical Sciences
    Depositing user: Pure Administrator
    Date deposited:24 Aug 2023 09:40
    Last modified:09 Apr 2024 04:13
    Related URLs:
    URI:https://strathprints.strath.ac.uk/id/eprint/86562
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