Qing-Xue-Xiao-Zhi formula attenuates atherosclerosis by inhibiting macrophage lipid accumulation and inflammatory response via TLR4/MyD88/NF-κB pathway regulation

Abstract

Background: Atherosclerosis is a progressive chronic disease characterised by aberrant lipid metabolism and a maladaptive inflammatory response. As atherosclerosis-driven cardiovascular disease remains the major cause of morbidity and mortality worldwide, more effective clinical therapies are urgently needed. Traditional Chinese Medicine (TCM) has demonstrated efficacy against atherosclerosis, with Qing-Xue-Xiao-Zhi formula (QXXZF) having been approved for clinical treatment of patients with atherosclerosis. However, the mechanisms underlying the anti-atherosclerotic activity of QXXZF remain unknown.

Purpose: To investigate the anti-atherosclerotic effect of QXXZF and reveal its mechanisms using preclinical models.

Methods: In vivo, apolipoprotein E-deficient (ApoE^-/-) mice were fed a high-fat and high-choline diet (HHD) to induce atherosclerosis. Serum metabolomic profiling was used to identify the concentration of trimethylamine N-oxide (TMAO) in mice. In vitro, RAW264.7 macrophages and bone marrow-derived macrophages (BMDMs) from WT and TLR4^-/- C57BL/6 mice were used to explore the effects of QXXZF on macrophages. After confirming the therapeutic effects of QXXZF, mass spectrometry and network pharmacology analyses were used to predict and investigate the main components and the anti-atherogenic mechanisms of QXXZF in the context of atherosclerosis.

Results: Our results showed QXXZF significantly suppressed the development of atherosclerosis, as evidenced by the decreased atherosclerotic plaques in the aorta and aortic root, reduced plasma lipid levels and decreased serum TMAO content in HHD-fed ApoE^-/- mice. Meanwhile, QXXZF effectively reduced foam cell formation in oxidized low-density lipoprotein (ox-LDL) and TMAO-stimulated RAW264.7 macrophages and BMDMs. Moreover, QXXZF facilitated reverse cholesterol transport (RCT) in macrophages by upregulating the expression of cholesterol efflux-related genes PPARγ/LXRα/ABCA1/ABCG1. Mechanistic studies revealed that QXXZF influenced cholesterol metabolism by inhibiting the TLR4-mediated nuclear factor kappa B (NF-κB) axis. Importantly, TLR4 knockout abolished the influence of QXXZF on macrophages.

Conclusion: QXXZF promotes lipid efflux and inhibits macrophage-mediated inflammation, producing a therapeutic effect against atherosclerosis. Our study provides new insight into the mechanism of QXXZF against atherosclerosis.

Keywords: Atherosclerosis; Inflammation; Lipid metabolism; Macrophages; Traditional Chinese Medicine.