Calycosin-7-Glucoside Alleviates Atherosclerosis by Inhibiting Ox-LDL-Induced Foam Cell Formation and Inflammatory Response in THP-1-Derived Macrophages via ATF-1 Activation Through the p38/MAPK Pathway.

PURPOSE: Macrophages play a pivotal role in the progression of atherosclerosis (AS), and targeting macrophage-associated pathological processes has emerged as a promising therapeutic strategy for AS. Flavonoids have demonstrated potent antioxidant properties with potential anti-atherosclerotic effects. This study aimed to investigate the therapeutic effects of the flavonoid calycosin-7-glucoside (CG) on AS and elucidate its underlying molecular mechanisms.

METHODS

Macrophages were differentiated from human monocytic THP-1 cells by treatment with phorbol-12-myristate-13-acetate (PMA). Foam cell formation was induced by exposing differentiated macrophages to oxidized low-density lipoprotein (ox-LDL). Protein and inflammatory cytokine expression levels were assessed using RT-qPCR, Western blot, and ELISA assays. Total cholesterol and free cholesterol levels were quantified using commercial kits, and lipid droplet accumulation was visualized using Nile red staining.

RESULTS

Activation of activating transcription factor 1 (ATF-1) was found to mediate CG-induced suppression of inflammatory responses and foam cell formation in ox-LDL-exposed THP-1-derived macrophages. CG treatment enhanced p38 MAPK activity, which was responsible for ATF-1 activation and subsequent inhibition of inflammation and foam cell formation. Mechanistically, ATF-1 facilitated CG-induced anti-atherosclerotic effects by upregulating liver X receptor beta (LXR-β) and cystic fibrosis transmembrane conductance regulator (CFTR), which are critical for lipid metabolism and inflammation regulation, respectively.

CONCLUSION

CG attenuates ox-LDL-induced foam cell formation and inflammatory responses in THP-1-derived macrophages by activating the p38 MAPK/ATF-1 signaling pathway, leading to the upregulation of LXR-β and CFTR. These findings highlight the potential of CG as a therapeutic agent for AS.