DAMP Laden Extracellular Vesicles From the Airways of Patients With Severe SARS-CoV-2 Respiratory Infection Compromise Inflammation and Cellular Metabolism.

Highly inflammatory mononuclear phagocytes (MNPs) cause tissue damage across the respiratory tract and other organs in response to infections such as SARS-CoV-2. Extracellular vesicles (EVs) can metabolically and phenotypically reprogram target cells, suggesting a potential role in COVID-19 pathology. We hypothesised that EVs drive inflammatory changes in COVID-19 and investigated their cargo and effects on MNPs. EVs and MNPs were isolated from matched peripheral blood and airways of ventilated patients with and without severe COVID-19, alongside healthy volunteer blood samples. Characterisation was performed using flow cytometry, microscopy, transcriptomics, PCR, proteomics, mass spectrometry, and bioenergetic profiling. We found that airway EVs from severe COVID-19 patients carried altered cargo, notably reduced miRNAs and enriched mitochondrial DNA and ATP, a difference absents in the circulation. These DAMP-rich EVs impaired healthy MNP function, suppressing cytokine production (e.g., IL-6, IFNα2), and inflammatory programs identified in the monocyte proteomic profile, while also disrupting oxidative phosphorylation-features matching airway MNPs in severe disease. Interaction of COVID-19 airway EVs with monocytes was diminished and these EVs had altered phosphatidylcholine/ lysophosphatidylcholine content. Our findings reveal a distinct EV cargo that reprograms immune metabolism, identifying a novel immunomodulatory mechanism exploited by SARS-CoV-2.