Sun Jian, Liu Hao-Rui, Zhu Ya-Xin, Zhang Wei, Shi Jing-Shan, Wu Qin, Xu Rui-Xia
Key Laboratory of Basic Pharmacology of Ministry of Education and Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical University, Zunyi, Guizhou 563006, P.R. China.
Cardiometabolic Center, State Key Laboratory of Cardiovascular Disease, National Center for Cardiovascular Diseases, Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, P.R. China.
Exp Ther Med. 2025 Jan 9;29(3):46. doi: 10.3892/etm.2025.12796. eCollection 2025 Mar.
Lindl. alkaloids (DNLA) are active ingredients that can be extracted from the traditional Chinese herb Lindl. DNLA exhibits hypoglycemic and antihyperlipidemia effects. However, to the best of our knowledge, the specific molecular mechanism by which DNLA can regulate lipid metabolism remains unclear. The aim of the present study was to investigate the effect of DNLA on lipopolysaccharide (LPS)-induced lipid metabolism in HepG2 cells and its potential mechanism. HepG2 cells were treated with LPS with or without different concentrations of DNLA (0, 0.035, 0.35 and 3.5 µg/ml) for 48 h. Cell viability was then detected using the Cell Counting Kit-8 assay. The 1,1'-dioctadecyl-3,3,3',3'-tetramethyl-indocarbocyanideperchlorate-low-density lipoprotein (LDL) uptake assay was used to examine LDL uptake. In addition, possible mechanisms were explored using western blot analysis. The effect of the combination of DNLA with rosuvastatin calcium on the expression levels of the LDL receptor (LDLR) and proprotein convertase subtilisin/Kexin type 9 (PCSK9) was examined. The results indicated that LPS stimulation reduced the uptake of LDL by HepG2 cells, decreased the intracellular LDLR content, and increased the expression levels of inducible degrader of the LDLR (IDOL) and liver X receptor (LXR)α. DNLA intervention reversed all of the aforementioned LPS-induced effects in HepG2 cells. Additional mechanistic experiments revealed that DNLA exerted its effects mainly by regulating the LXRα/IDOL/LDLR pathway. It was shown that DNLA also reduced the expression levels of PCSK9, sterol regulatory element binding protein 2 and hepatocyte nuclear factor 1α. In addition, DNLA decreased the expression levels of PCSK9 in rosuvastatin calcium-induced HepG2 cells. Notably, DNLA was able to decrease 3-hydroxy-3-methylglutaryl-coenzyme A reductase and increase cytochrome p450 7A1 expression at the protein level, which are rate-limiting enzymes in cholesterol synthesis and metabolism. Collectively, these data suggested that DNLA could enhance LDL uptake of HepG2 cells by increasing LDLR expression through the LXRα/IDOL/LDLR pathway to alleviate the effects induced by LPS, suggesting the potential benefit of DNLA in improving lipid metabolism disorders.
林氏生物碱（DNLA）是可从传统中药林氏中提取的活性成分。DNLA具有降血糖和抗高血脂作用。然而，据我们所知，DNLA调节脂质代谢的具体分子机制仍不清楚。本研究的目的是探讨DNLA对脂多糖（LPS）诱导的HepG2细胞脂质代谢的影响及其潜在机制。将HepG2细胞用含或不含不同浓度DNLA（0、0.035、0.35和3.5μg/ml）的LPS处理48小时。然后使用细胞计数试剂盒-8检测细胞活力。采用1,1'-二辛基-3,3,3',3'-四甲基吲哚羰花青高氯酸盐-低密度脂蛋白（LDL）摄取试验检测LDL摄取。此外，通过蛋白质印迹分析探索可能的机制。检测了DNLA与瑞舒伐他汀钙联合使用对低密度脂蛋白受体（LDLR）和前蛋白转化酶枯草溶菌素/克新9型（PCSK9）表达水平的影响。结果表明，LPS刺激降低了HepG2细胞对LDL的摄取，降低了细胞内LDLR含量，并增加了LDLR诱导降解物（IDOL）和肝脏X受体（LXR）α的表达水平。DNLA干预逆转了上述所有LPS诱导的HepG2细胞效应。进一步的机制实验表明，DNLA主要通过调节LXRα/IDOL/LDLR途径发挥作用。结果表明，DNLA还降低了PCSK9、固醇调节元件结合蛋白2和肝细胞核因子1α的表达水平。此外，DNLA降低了瑞舒伐他汀钙诱导的HepG2细胞中PCSK9的表达水平。值得注意的是，DNLA能够在蛋白质水平上降低3-羟基-3-甲基戊二酰辅酶A还原酶并增加细胞色素p450 7A1的表达，它们是胆固醇合成和代谢中的限速酶。总体而言，这些数据表明，DNLA可通过LXRα/IDOL/LDLR途径增加LDLR表达来增强HepG2细胞对LDL的摄取，以减轻LPS诱导的效应，提示DNLA在改善脂质代谢紊乱方面的潜在益处。
