Supplementary Material for: Glycyrrhizin, a High-Mobility Group Box 1 Inhibitor, Improves Lipid Metabolism and Suppresses Vascular Inflammation in Apolipoprotein E Knockout Mice

Background: High-mobility group box protein 1 (HMGB1) is known to have proinflammatory properties; however, the mechanisms by which HMGB1 influences immune responses during atherosclerosis (AS) development are not well understood. Thus, this study investigated the relationship between HMGB1 and vascular inflammation in Apoe–/– mice and whether glycyrrhizin (GLY), a small inhibitor of HMGB1, could have atheroprotective effects in AS. Methods: Apoe–/– mice on a high-fat diet were treated with GLY (50 mg/kg) or vehicle by gavage once daily for 12 weeks, respectively. Results: The GLY group exhibited significantly decreased serum lipid levels, atherosclerotic plaque deposition, and serum HMGB1 levels, as well as an increased Treg/Th17 ratio. The GLY group displayed increased interleukin-10 (IL-10) and IL-2 expression and decreased IL-17A and IL-6 expression. Furthermore, the GA treatment significantly reduced STAT3 phosphorylation in Th17 cells and increased STAT5 phosphorylation in Treg cells. Conclusions: Our findings indicate that the attenuation of atherosclerotic lesions in Apoe–/– mice by GLY might be associated with the amelioration of lipid metabolism abnormalities, inhibition of HMGB1 expression, and alterations in the Treg/Th17 ratio.

背景：已知高迁移率族蛋白B1（High-mobility group box protein 1，HMGB1）具有促炎活性，但HMGB1在动脉粥样硬化（Atherosclerosis，AS）发生发展过程中调控免疫应答的具体机制仍未明确。本研究旨在探讨HMGB1与Apoe–/–小鼠血管炎症的关联，以及HMGB1的小分子抑制剂甘草酸（glycyrrhizin，GLY）是否可在AS模型中发挥抗动脉粥样硬化作用。
方法：将高脂饲料喂养的Apoe–/–小鼠随机分为两组，分别经灌胃给予50 mg/kg的GLY或赋形剂，每日1次，连续给药12周。
结果：与赋形剂对照组相比，GLY组小鼠的血清脂质水平、动脉粥样硬化斑块沉积量及血清HMGB1水平均显著降低，同时调节性T细胞（Regulatory T cell，Treg）与辅助性T细胞17（T helper 17 cell，Th17）的细胞比值显著升高。GLY组小鼠的白细胞介素-10（Interleukin-10，IL-10）与IL-2的表达水平上调，IL-17A及IL-6的表达水平下调。此外，GLY处理可显著降低Th17细胞中信号转导与转录激活因子3（Signal Transducer and Activator of Transcription 3，STAT3）的磷酸化水平，并上调Treg细胞中信号转导与转录激活因子5（Signal Transducer and Activator of Transcription 5，STAT5）的磷酸化水平。
结论：本研究结果显示，GLY对Apoe–/–小鼠动脉粥样硬化病变的缓解作用，可能与其改善脂质代谢异常、抑制HMGB1表达以及调节Treg/Th17细胞比值密切相关。