­­­­­­­A type I IFN, prothrombotic hyperinflammatory neutrophil signature is distinct for COVID-19 ARDS­­­

Abstract

Background: Acute respiratory distress syndrome (ARDS) is a severe critical condition with a high mortality that is currently in focus given that it is associated with mortality caused by coronavirus disease 2019 (COVID-19). Neutrophils play a key role in the lung injury characteristic of non-COVID-19 ARDS and there is also accumulating evidence of neutrophil mediated lung injury in patients who succumb to infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Methods: We undertook a functional proteomic and metabolomic survey of circulating neutrophil populations, comparing patients with COVID-19 ARDS and non-COVID-19 ARDS to understand the molecular basis of neutrophil dysregulation. Results: Expansion of the circulating neutrophil compartment and the presence of activated low and normal density mature and immature neutrophil populations occurs in ARDS, irrespective of cause. Release of neutrophil granule proteins, neutrophil activation of the clotting cascade and upregulation of the Mac-1 platelet binding complex with formation of neutrophil platelet aggregates is exaggerated in COVID-19 ARDS. Importantly, activation of components of the neutrophil type I interferon responses is seen in ARDS following infection with SARS-CoV-2, with associated rewiring of neutrophil metabolism, and the upregulation of antigen processing and presentation. Whilst dexamethasone treatment constricts the immature low density neutrophil population, it does not impact upon prothrombotic hyperinflammatory neutrophil signatures. Conclusions: Given the crucial role of neutrophils in ARDS and the evidence of a disordered myeloid response observed in COVID-19 patients, this work maps the molecular basis for neutrophil reprogramming in the distinct clinical entities of COVID-19 and non-COVID-19 ARDS.

Mitochondrial translation is required for sustained killing by cytotoxic T cells

“…Protein lysates were generated from cell pellets as per (42) but using a lysis buffer of 5% SDS, 50 mM TEAB pH 8.5, and 10 mM TCEP. Protein clean up and peptide generation was performed by the S-Trap method (43) as per manufacturer protocol (Protifi) and as previously described (44).…”

“…For WT/KO and CHX-treated samples, 2 µg of peptide was analyzed per sample. Samples were injected onto a nanoscale C18 reverse-phase chromatography system (UltiMate 3000 RSLC nano, ThermoFisher) then electrosprayed into an Q Exactive HF-X Mass Spectrometer (Thermo Scientific) as described in (44). Analysis for doxycycline-treated samples had the following differences: 1.5 µg peptide was injected per sample, analysis was performed on Orbitrap Exploris 480 Mass Spectrometer (ThermoFisher), sample were loaded at 10 μl/min onto trap column and the easy spray source operated in positive mode with spray voltage at 2.445 kV, and the ion transfer tube temperature at 250°C.…”

“…Analysis for doxycycline-treated samples had the following differences: 1.5 µg peptide was injected per sample, analysis was performed on Orbitrap Exploris 480 Mass Spectrometer (ThermoFisher), sample were loaded at 10 μl/min onto trap column and the easy spray source operated in positive mode with spray voltage at 2.445 kV, and the ion transfer tube temperature at 250°C. The data were processed, searched, and quantified with Spectronaut (45) 14 using the directDIA option using the same analysis settings as (44). The directDIA data were searched against a mouse hybrid database from databases in July 2019 Uniprot release described in (42).…”

Circulating Type I Interferon Levels and COVID-19 Severity: A Systematic Review and Meta-Analysis

“…The IFN-I response can recruit several immune cells and lead to inflammatory disease, and this can develop beneficial or detrimental outcomes for the host (17). Despite its great importance in the antiviral response, the role of IFN-I in COVID-19 is complex (28)(29)(30); some studies have suggested a protective role for IFN-I during infection (31,32), while other studies suggested a deleterious role for IFN-I in COVID-19 (33,34).…”

The Advent of COVID-19; Periodontal Research Has Identified Therapeutic Targets for Severe Respiratory Disease; an Example of Parallel Biomedical Research Agendas

“…This phenotype of hyperinflammatory PMNs has also been observed to play an important role in the pathogenesis of systemic diseases such as diabetes and cardiovascular disease, suggesting an epidemiological association between periodontal diseases and systemic conditions (65, 66). More importantly, these hyperactivated phenotypes have been observed in severe cases of COVID-19 (67,68), as well as in aging-related conditions (69). Therefore, the presence of periodontitis in patients who are infected with SARS-CoV-2 could represent an as yet unrecognized comorbidity that could contribute to more severe symptoms of COVID-19.…”