Elastase and myeloperoxidase participate in neutrophil extracellular trap release stimulated by SARS-CoV-2.

COVID-19 is a disease triggered by SARS-CoV-2 and some individuals develop a severe form that can progress to multiple organ failure. Neutrophils have been described as responsible for the release of neutrophil extracellular traps (NETs). The role of the elastase and myeloperoxidase (MPO) in NET release by neutrophils stimulated by SARS-CoV-2 infection was not addressed, and it was the aim of the present study. The NET release by human neutrophils infected with SARS-CoV-2 depends on elastase/MPO migration to the nucleus. Moreover, elastase/MPO migration is a consequence of PKC and PI3K kinase activation, leading to reactive oxygen species generation by the neutrophil mitochondria and NOX-2. We also reanalyzed the single-cell RNA sequencing data available in a database and demonstrated that neutrophils from bronchoalveolar lavage (BAL) fluid of patients with COVID-19 present increased expression of genes involved in the formation of the NOX2 complex, PKC delta and members of the PI3K family. In summary, the release of NETs by neutrophils in response to SARS-CoV-2 infection depends on the sequential activation of the PKC/PI3K/ROS pathway, inducing elastase/MPO migration to the nucleus triggering the NET formation. Thus, our study demonstrates new insights into the signaling pathways that induce NETs in response to SARS-CoV-2, highlighting new targets for studies and therapies for COVID-19.