Dust exposure impacts haemophilus influenzae attachment and invasion of human airway epithelial cells

Background The development and progression of chronic lung diseases such as bronchiectasis involve recurrent episodes of severe bacterial respiratory infections. Inhaled environmental dust exposure can exacerbate immune responses to respiratory infections in mice. Whether dust exposure leads to more common and severe bacterial infections in the human airway is not yet known. Aim To determine the impact of community-sampled geogenic dust PM 10 (particulate matter Haemophilus influenzae (NTHi) infection. Methods Geogenic dust was collected from remote towns in Western Australia, and PM 10 was extracted. NuLi-1 cells were exposed to PM 10 (10µg/mL in PBS) in vitro for 24h before the addition of live NTHi-86 (MOI 10:1) for 3h. Trypan blue staining was used to determine cell viability, and bacterial infection (attachment and invasion) was determined using a standard gentamicin survival assay. Epithelial release of IL-6 and IL-8 was assessed using a bead based immunoassay. Results In cells exposed to dust PM 10 , both NTHi attachment and invasion was significantly increased compared with cells exposed to PBS only (p Conclusion Geogenic dust preparations increased NTHi attachment and invasion of human airway cells and may contribute to more common and severe respiratory infections. This has important implications for lung health in individuals living in arid environments, who are exposed to high loads of geogenic dust.