Recreating the Human Alveolar Macrophage Niche to Study Bacterial Pneumonia
Date
2024-07-02
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Abstract
Staphylococcus aureus (SA) pneumonia infections are widespread in Canada, particularly in hospitalized patients, and are associated with high mortality rates and significant financial costs to the healthcare system. A major limitation in our ability to design treatments to alleviate disease burden is a lack of understanding regarding how the lung’s frontline defenders, such as alveolar macrophages, interact with SA bacteria in humans. Unfortunately, there are a lack of models which accurately model human alveolar macrophages (AMs). To address this, we have designed a human lung on chip (LoC) device to improve human AM phenotypic differentiation in culture to investigate the interactions of SA with AMs. First, we used Mass Cytometry (CyTOF) to characterize the surface marker expression of PBMC-derived AMs cultured in the LoC device for three days. Results demonstrated PBMC-AMs acquired expression of numerous AM markers (eg. CD11b, CD169, CD206, and CD163) to similar levels as primary AMs derived from bronchoscopy samples. Next, we characterized PBMC-derived AM behavior in the LoC and their influence on LoC tissue morphology and barrier function. Results showed PBMC-AMs had similar migratory behaviors and morphology to what has been previously reported in vivo further validating our model. Subsequently, we examined the impact of bacterial infection using a 4-hour incubation with SA and found dramatically altered AM phenotype including altered marker expression and reduced migration. Finally, we incubated various strains and knockouts of SA in the LoC +/- PBMCs and found differing rates of bacterial abundance. Overall, we anticipate our model will offer an avenue for future studies seeking to understand human lung disease, particularly as it relates to SA lung infection.
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Keywords
Alveolar Macrophage, Lung-On-Chip, Pneumonia, MRSA
Citation
Nelson, T. (2024). Recreating the human alveolar macrophage niche to study bacterial pneumonia (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.