Modeling viral and bacterial infections in human lung organotypic systems reveals strain specific host responses
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In this study, we developed novel lung organoid-on-chip models that elucidate differential human tissue response to various strains of respiratory pathogens: Streptococcus pneumoniae and SARS-CoV-2. We show that human fetal-derived distal lung epithelial cells are readily expandable in 3D as organoids, thereby providing a highly sustainable source of lung progenitor cells. These 3D organoid progenitors can then be induced to produce airway and alveolar organoids on microfluidic devices. Upon challenge with Streptococcus pneumoniae , a bacterium known to cause pneumonia, a rapid and strain-dependent colonization was observed at the epithelial surface of alveolar chips. We also assessed SARS-CoV-2 infection in the alveoli-on-chip system and observed that the Delta variant exhibited greater infectivity as compared to the Omicron BA.5. Both SARS-CoV-2 variants induced potent interferon responses and triggered the expression of different interferon-stimulated genes. Our results demonstrate that strain-specific host defense mechanisms can be recapitulated in human-organoid-based microfluidic systems, paving the way for the use of such platforms for more targeted assessments of human response to novel emergent pathogen strains.
Highlights
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Human fetal epithelial lung stem cells can be expanded as multipotent organoids and differentiated into both airway or alveolar organoids
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Multipotent lung organoids efficiently produce functional epithelia of small airway or alveoli when grown on-chip.
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Streptococcus pneumoniae inoculation in alveoli-on-chip mimics the early stages of bacterial colonization in lung epithelia
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Alveoli on-chip system recapitulates variant-specific interactions. SARS-CoV-2 Delta replicates but not Omicron BA.5.
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Robust interferon response upon SARS-CoV-2 infection shows Alveoli on-chip can model innate immune responses.
