Regulation and impact of adaptor protein SQSTM1/p62 in the replication cycle of Respiratory Syncytial Virus in Airway Epithelial Cells
Introduction: Human respiratory syncytial virus (RSV) causes a high rate of morbidity and mortality worldwide in children, immunocompromised and elderly people. There is an urgent need for effective antiviral treatments and vaccines for RSV. Airway epithelial cells (AECs) are the primary target of RSV and constitute the first line of defense through distinct mechanisms, including intrinsic antiviral responses. The p62/SQSTM1 protein has multiple cellular functions including cell signaling and sequestration of specific ubiquitinated cargo (i.e. proteins/organelles and intracellular bacteria) for autophagic degradation. The replication of several viruses has been shown to be sensitive to p62 levels. The goal of our study is to investigate the role of p62 in the regulation of RSV replication. Methods and Results: Analysis of p62 expression in A549 cells showed that p62 is induced and phosphorylated during early stages of RSV infection, followed by degradation at later times. P62 silencing diminished the intracellular accumulation of viral proteins, while causing increased release of infectious virions. Additionally, we observed that the stable expression of Microtubule-associated protein 1A/1B-light chain 3 (LC3), which recruits p62 and its cargos to the autophagosome for autophagy degradation, reduces recRSV-GFP replication. Studies are currently undertaken to determine the molecular mechanisms involved in p62-dependent regulation of RSV replication. Conclusion: Our results highlight a key role of p62 in the replication of RSV. These studies will help to define whether p62 might represent a potential therapeutic target to fight RSV infection.
p62/SQSTM1 Respiratory syncytial virus RSV Airway epithelial cells Antiviral response UPS Autophagy Viral replication