The sudden outbreak of SARS-CoV-2 infected disease (COVID-19), initiated from Wuhan, China, has rapidly grown into a global pandemic . Emerging evidence has implicated extracellular vesicles (EVs), a key intercellular communicator, in the pathogenesis and treatment of COVID-19 . In the pathogenesis of COVID-19, cells that express ACE2 and CD9 can transfer these viral receptors to other cells via EVs, making recipient cells more susceptible for SARS-CoV-2 infection . Once infected, cells release EVs packaged with viral particles that further facilitate viral spreading and immune evasion, aggravating COVID-19 and its complications . In contrast, EVs derived from stem cells, especially mesenchymal stromal/stem cells, alleviate severe inflammation (cytokine storm) and repair damaged lung cells in COVID-19 by delivery of anti-inflammatory molecules . These therapeutic beneficial EVs can also be engineered to function as a drug delivery platform or vaccine to fight against COVID-19 . Therefore, EVs from diverse sources exhibit distinct effects in regulating viral infection, immune response, and tissue damage/repair, functioning as a double-edged sword in COVID-19 . Here, we summarize the recent progress in understanding the pathological roles of EVs in COVID-19 . A comprehensive discussion of the therapeutic effects/potentials of EVs is also provided.
Index: COVID-19, Cytokine storm, Extracellular vesicle, Inflammation, SARS-CoV-2