Respiratory Syncytial Virus induces the classical ROS-dependent NETosis through PAD-4 and necroptosis pathways activation

Abstract

Respiratory syncytial virus (RSV) is a major cause of diseases of the respiratory tract in young children and babies, being mainly associated with bronchiolitis. RSV infection occurs primarily in pulmonary epithelial cells and, once infection is established, an immune response is triggered and neutrophils are recruited. In this study, we investigated the mechanisms underlying NET production induced by RSV. We show that RSV induced the classical ROS-dependent NETosis in human neutrophils and that RSV was trapped in DNA lattices coated with NE and MPO. NETosis induction by RSV was dependent on signaling by PI3K/AKT, ERK and p38 MAPK and required histone citrullination by PAD-4. In addition, RIPK1, RIPK3 and MLKL were essential to RSV-induced NETosis. MLKL was also necessary to neutrophil necrosis triggered by the virus, likely promoting membrane-disrupting pores, leading to neutrophil lysis and NET extrusion. Finally, we found that RSV infection of alveolar epithelial cells or lung fibroblasts triggers NET-DNA release by neutrophils, indicating that neutrophils can identify RSV-infected cells and respond to them by releasing NETs. The identification of the mechanisms responsible to mediate RSV-induced NETosis may prove valuable to the design of new therapeutic approaches to treat the inflammatory consequences of RSV bronchiolitis in young children.

Post-Translational Protein Deimination Signatures in Serum and Serum-Extracellular Vesicles of Bos taurus Reveal Immune, Anti-Pathogenic, Anti-Viral, Metabolic and Cancer-Related Pathways for Deimination

“…Only PAD4 was reported in this COVID-19 patient cohort. Importantly, as PAD4 is involved in gene regulation and also considered one key-driver of NETosis [37], reduced PAD4 levels, observed in these COVID-19 patients, may contribute to less defences against viral infection due to gene regulatory changes, changes in deimination of immune related proteins, or impaired NETosis in these individuals. Whether the virus manipulates PAD4 expression, as an immune evasion mechanism, or whether individuals with lower PAD4 are more prone to SARS-CoV-2 infection, remains to be further investigated.…”

“…Post-translational deimination of cow Ig's, which are reported in the current study for the first time, have yet to be further explored. Roles for PADs in anti-viral responses have previously been identified via the generation of NETosis [37], which can be PAD-mediated and is also a recognized mechanism in anti-pathogenic functions in cattle [109]. Deimination has also been identified to modulate chemokines in anti-HIV responses [40] and higher levels of anti-cyclic citrullinated peptide antibodies have been found sera of HIV patients [110].…”

Coxsackievirus A6 Induces Necroptosis for Viral Production

“…Often, necroptosis is associated with increases in the level of ROS (Takemoto et al, 2014;Schenk and Fulda, 2015;Muraro, 2018). To investigate the relationship between CA6 infection and ROS, the level of ROS was detected, CA6 infection did not change the level of ROS compared to the mock-infection ( Figure 5A).…”

“…RIPK3-dependent necroptosis has been demonstrated to be activated in response to bovine parvovirus (BPV) (Abdel-Latif et al, 2006), murine cytomegalovirus (Upton et al, 2012), Influenza A virus (Thapa et al, 2016), and reovirus (Berger et al, 2017). Furthermore, high amounts of reactive oxygen species (ROS) have been shown to induce necroptosis (Takemoto et al, 2014;Schenk and Fulda, 2015;Muraro, 2018).…”

Syncitial virus respiratory infections in children – immunological aspects

“…Upon infection of alveolar epithelial cells or lung fibroblasts NET-DNA is released by neutrophils, pointing out that neutrophils can identify HRSV-infected cells and respond to infection by releasing NETs. This recently shown mechanism can lead to designing of new therapeutic approaches in HRSV infection (Muraro et al, 2018). HRSV induces in airway epithelial cells an inflammation triggered by epidermal growth factor receptor (EGFR).…”