Mesenchymal stem cell derived exosomes mitigate COVID-19 cytokine storm via Annexin A1 and TGF-β mediated MAPK pathway inhibition

BACKGROUND: Severe COVID-19 is marked by a dysregulated inflammatory response, known as a cytokine storm, resulting in acute respiratory distress syndrome (ARDS) and multiple organ failure. Mesenchymal stem cell-derived exosomes (MSC-Exos) have demonstrated potential as immunomodulatory agents. This work investigates the possibility of MSC-Exos to mitigate excessive inflammation in COVID-19 by targeting the mitogen-activated protein kinase (MAPK) signalling pathway. METHODOLOGY: We integrated molecular docking analysis between TGF-β and Annexin A1 as exosomal proteins and key component proteins of the MAPK pathway (p38, ERK1/2, JNK1). The in-silico results were then validated in vivo using a Syrian hamster model of SARS-CoV-2 infection. Quantitative PCR (qPCR), western blotting, and histological examination were employed to evaluate the effects of MSC-Exos therapy on MAPK pathway activation, cytokine production, and lung tissue pathology. RESULTS: The in-silico study revealed extensive hydrogen bonding and hydrophobic interactions at the protein-protein interfaces between exosomal proteins and MAPK components. These interactions suggest that exosomal proteins may modulate MAPK signaling pathways. In vivo, MSC-Exos administration led to marked downregulation of pivotal genes in the MAPK signaling pathway (MEKK1, MEKK2, MEKK3), diminished phosphorylation of JNK1, p38, and ERK1/2, and lowered production of pro-inflammatory cytokines (IL-1β, IL-6, TNF-α). Histopathological examination demonstrated ameliorated lung tissue structure, characterized by diminished alveolar wall thickness and decreased immune cell infiltration. CONCLUSION: MSC-Exos elicit immunomodulatory effects in SARS-CoV-2-Infected hamsters, partially by directly targeting and blocking the MAPK signaling pathway. These findings offer a compelling justification for the clinical assessment of MSC-Exos as a therapeutic approach to alleviate the cytokine storm and enhance outcomes in severe COVID-19 by targeting the ACE2-Independent pathway.