Panax notoginseng saponin mitigates glycolysis to regulate macrophage polarization and sphingolipid metabolism via hypoxia-inducible factor-1 to alleviate atherosclerosis

BACKGROUND: Panax notoginseng saponin (PNS) has shown potent activities in treating patients with atherosclerosis (AS), whereas its immunometabolic mechanism remained unknown. OBJECTIVES: To elucidate the characteristics of metabolomics of AS plaque and identify immunometabolic mechanisms of PNS in treating AS. METHODS: PNS components were characterized using ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MSE). Spatial Metabolomics was performed to reveal characteristics of plaque from atherosclerosis patients. Then we verified different glycolysis and sphingolipid metabolites between chronic coronary disease (CCD) patients and health control (HC). In vivo and in vitro experiments were performed to study the relationship among hypoxia-inducible factor-1 α (Hif-1α), glycolysis, and macrophage polarization, as well as the protective role and underlying mechanism of PNS in AS. RESULTS: Among 8058 metabolites, 117 metabolites were greatly downregulated and 355 metabolites were remarkably upregulated in the plaque area. Sphingolipid metabolism ranked the top according to KEGG analysis, among which sphingosine-1-phosphate (S1P) and specifically sphingomyelin (SPH) were significantly reduced in CCD patients. Overexpression of Hif-1α could induce macrophage M1 polarization, enhance glycolysis, promote excessive UDP-glucose ceramide glucosyltransferase (UGCG) production, and reduce S1P, resulting in a proinflammatory response. Chemical characterization of PNS verified the presence of the principal saponins (R1, Rg1, Rb1, Rd, Re), which subsequently was shown to act as a novel Hif-1α inhibitor, exerting its anti-atherosclerotic effects through multiple pathways, specifically, downregulating key glycolytic regulators (PFKFB3, GLUT1, HK2) and suppressing downstream glycolysis; promoting the expression of MRC1/iNOS to inhibit M1 macrophage polarization; upregulating S1P to modulate sphingolipid metabolism, thereby alleviating AS. CONCLUSION: These findings emphasize the anti-AS effects of PNS through a novel immunometabolic mechanism, particularly its role as a Hif-1α inhibitor that disrupts such pathways driving AS progression.