Abstract
Introduction: Eosinophils account for approximately a third of COPD exacerbations. We propose that excessive ROS production during an eosinophilic exacerbation may contribute to tissue damage in patients with COPD leading to disease progression.
Methods: Bulk RNA sequencing of isolated peripheral blood eosinophils performed on patients with COPD experiencing an eosinophilic exacerbation (n=4), at a stable, non-eosinophilic disease state (n=4), and healthy volunteers (n=4). To investigate the molecular mechanisms of ROS production, we measured intracellular ROS burst using Fc OxyBURST® green and mitochondrial specific ROS by mitoSOX red in a flow cytometer-based assay. Extracellular ROS was detected using OxyBURST® H2HFF Green BSA in a fluorometric assay +/- PMA stimulation. A549 cells were cultured with eosinophils and ROS damage assessed with the DNA damage ELISA kit.
Results: RNA sequencing identified several genes involved in ROS production that were upregulated in eosinophilic exacerbations compared with healthy volunteers and stable, non-eosinophilic COPD patients. Moreover, we found that eosinophil extracellular ROS production was increased and production more rapid during an exacerbation in comparison to stable state. Notably, eosinophils had higher oxidative burst capacity and produced more mitochondrial associated ROS upon stimulation compared with matched neutrophil controls.
Conclusions: These data suggest that during an eosinophilic exacerbation, increased ROS production performs an active role in COPD pathogenesis by causing epithelial damage and initiating further local inflammation within the lung.
Footnotes
Cite this article as ERJ Open Research 2022; 8: Suppl. 8, 117.
This article was presented at the 2022 ERS Lung Science Conference, in session “Poster Session 2”.
This is an ERS Lung Science Conference abstract. No full-text version is available. Further material to accompany this abstract may be available at www.ers-education.org (ERS member access only).
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