Rui Chen,1,* Jiaqian Fang,2,* Hairuo Sun,3,* Zhiyong Yu,4,* Yangfan Huang,2 Yaohong Song1 

1Department of Cardiology, Nanjing Hospital of Chinese Medicine Affiliated to Nanjing University of Chinese Medicine, Nanjing, People’s Republic of China; 2Nanjing University of Chinese Medicine, Nanjing, People’s Republic of China; 3College of Chemistry and Chemical Engineering, China University of Petroleum (East China), Qingdao, People’s Republic of China; 4Department of Cardiology, Taihe County People’s Hospital, Fuyang, People’s Republic of China

*These authors contributed equally to this work

Correspondence: Yaohong Song, Department of Cardiology, Nanjing Hospital of Chinese Medicine Affiliated to Nanjing University of Chinese Medicine, Nanjing, People’s Republic of China, Email sfy003@njucm.edu.cn

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.

Keywords: calycosin-7-glucoside, macrophage, foam cell formation, inflammatory response