Osteopontin protects against pneumococcal infection in a murine model of allergic airway inflammation

Research output: Contribution to journalArticle

Abstract

Background: In atopic asthma, chronic Th2-biased inflammation is associated with an increased risk of pneumococcal infection. The anionic phosphoglycoprotein osteopontin (OPN) is highly expressed in asthma and has been ascribed several roles during inflammation. This study aimed to investigate whether OPN affects inflammation and vulnerability to pneumococcal infection in atopic asthma. Methods: House dust mite (HDM) extract was used to induce allergic airway inflammation in both wild-type (Spp1+/+) and OPN knockout (Spp1−/−) C57BL/6J mice, and the airway was then infected with Streptococcus pneumoniae. Parameters reflecting inflammation, tissue injury, and bacterial burden were measured. In addition, samples from humans with allergic asthma were analyzed. Results: Both allergen challenge in individuals with allergic asthma and the intranasal instillation of HDM in mice resulted in increased OPN levels in bronchoalveolar lavage fluid (BALF). More immune cells (including alveolar macrophages, neutrophils, eosinophils, and lymphocytes) and higher levels of proinflammatory cytokines were found in Spp1−/− mice than in Spp1+/+ mice. Moreover, OPN-deficient mice exhibited increased levels of markers reflecting tissue injury. Upon infection with S. pneumoniae, Spp1+/+ mice with allergic airway inflammation had a significantly lower bacterial burden in both BALF and lung tissue than did Spp1−/− mice. Furthermore, Spp1−/− mice had higher levels of cytokines and immune cells in BALF than did Spp1+/+ mice. Conclusion: OPN reduces inflammation, decreases tissue injury, and reduces bacterial loads during concurrent pneumococcal infection and allergic airway inflammation in a murine model. These findings suggest that OPN significantly affects vulnerability to pneumococcal infection in atopic asthma.

Details

Authors
Organisations
External organisations
  • Skåne University Hospital
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Respiratory Medicine and Allergy
  • Infectious Medicine

Keywords

  • allergy, asthma, host defense, house dust mite, osteopontin, Streptococcus pneumoniae
Original languageEnglish
Pages (from-to)663-674
JournalAllergy: European Journal of Allergy and Clinical Immunology
Volume74
Issue number4
Early online date2018 Oct 26
Publication statusPublished - 2019
Publication categoryResearch
Peer-reviewedYes