Huashi Baidu granules alleviate LPS-induced endothelial injury by modulating the AKT1-FOXO3a signaling pathway

Huashi Baidu granules (HSBD) are a proprietary Chinese medicine demonstrated to be effective in treating COVID-19 patients. Although HSBD has shown promising clinical efficacy, its mechanism of endothelial protection remains unclear.

This study aimed to elucidate the mechanism by which HSBD alleviates endothelial injury in acute lung injury (ALI).

A lipopolysaccharide (LPS)-induced ALI mouse model and HUVECs were used to investigate the endothelial protective effects of HSBD. Proteomic analysis of lung tissue was conducted to explore the underlying mechanisms. Hematoxylin and eosin (H&E) staining, Evans blue albumin (EBA) leakage assays, ELISA, endothelial permeability assays, Western blotting (WB), qRT-PCR and Immunofluorescence (IF) were employed to assess endothelial injury and identify relevant signaling pathways.

HSBD significantly ameliorated histopathological lung injury and reduced endothelial permeability, as evidenced by EBA staining and lung tissue fluorescence imaging. HSBD also suppressed the expression of IL-6, TNF-α, and IL-1β in both serum and lung tissue. Proteomics analysis revealed enrichment of differentially expressed proteins in the FOXO signaling pathway. Western blotting and qRT-PCR confirmed that HSBD downregulated phosphorylated AKT1 and FOXO3a levels, while upregulating VE-cadherin (cadherin-5) expression both in vitro and in vivo, immunofluorescence of mouse lung sections corroborated these findings. By showing that the AKT activator SC79 blocked the protective effects of HSBD, our results indicate that AKT1 activation is essential for HSBD's action against endothelial injury.

Collectively, these findings demonstrate that HSBD mitigates LPS-induced endothelial injury by modulating the AKT1-FOXO3a signaling pathway, offering mechanistic insight into its potential therapeutic role in COVID-19 from an endothelial protection perspective.