Exosomes/EVs: Late Breaking Abstract: MSC-DERIVED EXTRACELLULAR VESICLES WITH ANTI-VIRAL EFFICACY ALLEVIATE VIRUS-INDUCED ACUTE RESPIRATORY DISTRESS SYNDROME

ABSTRACT

Background & Aim: From SARS-CoV-1 outbreak in 2002 to the most recent SARS-CoV-2 pandemic (COVID-19), emergence of viral diseases has repeatedly threatened humanity over the recent decades. These viral diseases mainly cause respiratory symptoms, which can even lead to death when appropriate measures are not taken. In this study, we investigated whether adipose tissue-derived mesenchymal stem cell EVs (ASC-EVs) can attenuate acute lung injury (ALI) induced by H1N1 influenza A virus and SARS-CoV-2 and by what mechanism the ant-viral effect may occurs. Methods, Results & Conclusion: EVs were isolated from ASC or HEK293T conditioned media by tangential flow filtration, and were characterized according to MISEV recommendation. Influenza A/ Puerto Rico/08/1934 (H1N1) and SARS-CoV-2 (NCCP43326) were used to model highly pathogenic human influenza A and SARS-CoV-2 virus infection, respectively, in mice and Syrian hamsters respectively. Treatment of ASC-EVs, from 0.15 x 109 to 5.0 x 109 particles/mL, showed inhibitory activities on cytopathic effects and replication of H1N1 and SARS-CoV-2 in MDCK cells and Vero E6 cells, respectively. In the mouse H1N1 influenza A virus induced acute lung injury (ALI) model, total of 4 daily injections of 1 x 1010 particles of ASC-EVs administration resulted in significantly increased survival rate by 30 – 40%, recovery of body weight, and improved clinical disease score from 9 dpi. In addition, ASC-EV treatment downregulated various inflammatory cytokines such as IL-1β, IL-6 and TNFα in lung tissue by up to 77%. In the Syrian hamster SARS-CoV-2 induced ALI model, total of 4 daily injections of ASC-EVs at a dose of 3 x 1010 or 1 x 1010 particles resulted recovery of body weights from 5 dpi, in a dose-dependent manner, by 9.7% - 12.75%. Further, ASC-EV treatment resulted in significant downregulation of viral genes and IL-1 beat in lung tissue. To elucidate the molecular mechanisms of the observed anti-viral effects of ASC-EVs, the role of multiple miRNAs and proteins present in the ASC-EVs were assessed in vitro. We identified one specific protein that conveyed anti-viral efficacy against the two studied viruses including SARS-CoV-2. Loss and gain of function studies revealed that this protein may be involved in the anti-viral efficacy of the ASC-EVs. Our findings support the concept that that ASC-EVs have anti-viral effects against virus induced ALI, which may have implications for the treatment of not only treatment COVID-19, but also future ALI-inducing virus diseases.