Qingfei Paidu decoction acts against human coronavirus 229E infection through dual synergistic mechanisms

Qingfei Paidu decoction (QFPDD) is a traditional Chinese medicine (TCM) formula based on the theory of "lung pathogen-dispersing and toxin-eliminating". It holds considerable ethnopharmacological importance in treating human coronavirus (HCoV) infection. This study explored its multi-target mechanisms, identifying two synergistic pathways, i.e., a novel miRNA-mediated antiviral pathway and a glycyrrhetinic acid (GA)-mediated anti-inflammatory pathway. These findings bridge traditional TCM knowledge with modern pharmacological understanding, underscoring the characteristic "multi-components, multi-targets, and synergistic effects" value of ethnomedicine.

To investigate the multiple action mechanisms of QFPDD against HCoV-229 E infection.

QFPDD-regulated miRNAs and QFPDD-derived metabolites in rat serum were identified via miRNA profiling and metabolomic analysis. Their core targets were then predicted bioinformatically and validated by measuring downstream metabolic changes. The antiviral effect of the key miRNA on HCoV-229 E was further evaluated in vitro.

QFPDD significantly downregulated a novel miRNA, novel-miR-89, knockdown of which suppressed HCoV-229 E replication in vitro. Bioinformatic and metabolic evidence indicated that QFPDD's downregulation of novel-miR-89 activated the classic antiviral protein kinase C (PKC) pathway by enhancing the activity of phospholipase C (PLC) activity. This was validated by decreased levels of phosphatidylcholine (PC) and increased levels of phosphorylcholine and 13 S-hydroxyoctadecadienoic acid (13 S-HODE), which linearly correlated with novel-miR-89 expression and regulatory role. Simultaneously, a well-known anti-inflammatory pathway mediated by GA/11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2) pathway was identified, driven by increased GA levels in QFPDD-treated rats due to hydrolysis of QFPDD-derived glycyrrhizic acid.

QFPDD acts against HCoV-229 E infection through a novel antiviral axis via the Novel-miR-89/PLC/PKC pathway. This newly identified mechanism is complemented by the anti-inflammatory effect mediated by the GA/11β-HSD2 pathway, which is derived from a specific phytochemical (glycyrrhizic acid) within the formula. It is indicated that these dual synergistic mechanisms may contribute to the basis for the therapeutic effects of QFPDD against HCoV infection.