A co-culture system with an organotypic lung slice and an immortal alveolar macrophage cell line to quantify silica-induced inflammation

PLoS One. 2015 Jan 30;10(1):e0117056. doi: 10.1371/journal.pone.0117056. eCollection 2015.

Abstract

There is growing evidence that amorphous silica nanoparticles cause toxic effects on lung cells in vivo as well as in vitro and induce inflammatory processes. The phagocytosis of silica by alveolar macrophages potentiates these effects. To understand the underlying molecular mechanisms of silica toxicity, we applied a co-culture system including the immortal alveolar epithelial mouse cell line E10 and the macrophage cell line AMJ2-C11. In parallel we exposed precision-cut lung slices (lacking any blood cells as well as residual alveolar macrophages) of wild type and P2rx7-/- mice with or without AMJ2-C11 cells to silica nanoparticles. Exposure of E10 cells as well as slices of wild type mice resulted in an increase of typical alveolar epithelial type 1 cell proteins like T1α, caveolin-1 and -2 and PKC-β1, whereas the co-culture with AMJ2-C11 showed mostly a slightly lesser increase of these proteins. In P2rx7-/- mice most of these proteins were slightly decreased. ELISA analysis of the supernatant of wild type and P2rx7-/- mice precision-cut lung slices showed decreased amounts of IL-6 and TNF-α when incubated with nano-silica. Our findings indicate that alveolar macrophages influence the early inflammation of the lung and also that cell damaging reagents e.g. silica have a smaller impact on P2rx7-/- mice than on wild type mice. The co-culture system with an organotypic lung slice is a useful tool to study the role of alveolar macrophages during lung injury at the organoid level.

MeSH terms

  • Animals
  • Caveolin 1 / metabolism
  • Caveolin 2 / metabolism
  • Cell Line
  • Cell Survival / drug effects
  • Coculture Techniques / methods*
  • Cytokines / metabolism
  • Epithelial Cells / metabolism
  • Female
  • Flow Cytometry
  • Immunohistochemistry
  • Inflammation / pathology*
  • Lung / pathology*
  • Macrophages, Alveolar / drug effects
  • Macrophages, Alveolar / metabolism
  • Macrophages, Alveolar / pathology*
  • Male
  • Mice, Inbred C57BL
  • Nanoparticles / toxicity
  • Protein Kinase C beta / metabolism
  • Receptors, Purinergic P2X7 / metabolism
  • Silicon Dioxide / toxicity*

Substances

  • Caveolin 1
  • Caveolin 2
  • Cytokines
  • P2rx7 protein, mouse
  • Receptors, Purinergic P2X7
  • Silicon Dioxide
  • Protein Kinase C beta

Grants and funding

The authors have no support or funding to report.