Proteomics reveals the pharmacological mechanism of flavonoids from Astragali Complanati Semen in preventing chronic liver injury.

Background: Total flavonoids from Astragali Complanati Semen (TFACS), the main active ingredients in Astragali Complanati Semen (ACS), have been shown to have a protective effect on chronic liver injury (CLI), but the hepatoprotective targets and signalling pathways involved are unclear.

Purpose: The aim of our study was to identify the anti-CLI targets and signalling pathways of TFACS and to comprehensively elucidate its mechanism of action via proteomics analysis combined with in vivo and in vitro experiments.

Methods: A CLI mouse model was generated via intraperitoneal injection of carbon tetrachloride (CCl) (CCl: olive oil = 1:4, 2 ml/kg, twice a week for 6 weeks). The hepatoprotective effect of TFACS was assessed by observing the pathological structure of the liver and analysing indicators of liver function. The key pathways and targets related to the hepatoprotective effect of TFACS were identified via 4D-label-free quantitative proteomics technology and further verified via in vivo indicator validation and in vitro cell experiments.

Results: TFACS administration significantly normalized the histopathological structure and function of the liver, decreased the levels of inflammatory factors and oxidative stress indicators, and reduced the iron staining area and the levels of hepcidin and iron in the liver compared with those in the CLI model. A total of 424 differentially expressed proteins (DEPs) were identified between the TFACS and model groups, and these DEPs were enriched in the focal adhesion, PI3K-Akt, and ferroptosis pathways. Akt1, Pik3ca, NF-κB p65, Itga5, Itgb5, Itga6, Prkca, Fn1, Tfrc, and Vdac3 were identified as key targets of TFACS. TFACS administration significantly reversed the changes in the gene and protein expression of the key targets compared with those in the model group. In addition, TFACS treatment significantly reduced the levels of inflammatory cytokines and inhibited Akt1, NF-κB p65 and FAK activation in lipopolysaccharide (LPS)-induced RAW 264.7 macrophages. In an erastin-induced l-O2 ferroptosis cell model, treatment with TFACS normalized the mitochondrial structure, reduced the protein levels of Tfrc and Vdac3, inhibited lipid peroxidation, and reduced the amount of Fe in the mitochondria.

Conclusion: TFACS protected against CLI, and its mechanism of action may be related to inhibition of the focal adhesion, PI3K/Akt and ferroptosis signalling pathways.