AUTHOR=Sun Le , Yu Fan , Yi Fan , Xu Lijia , Jiang Baoping , Le Liang , Xiao Peigen 

TITLE=Acteoside From Ligustrum robustum (Roxb.) Blume Ameliorates Lipid Metabolism and Synthesis in a HepG2 Cell Model of Lipid Accumulation

JOURNAL=Frontiers in Pharmacology

VOLUME=10

YEAR=2019

URL=https://www.frontiersin.org/journals/pharmacology/articles/10.3389/fphar.2019.00602

DOI=10.3389/fphar.2019.00602

ISSN=1663-9812

ABSTRACT=<p>We aimed to ascertain the mechanism underlying the effects of acteoside (ACT) from <italic>Ligustrum robustum</italic> (Roxb.) Blume (Oleaceae) on lipid metabolism and synthesis. ACT, a water-soluble phenylpropanoid glycoside, is the most abundant and major active component of <italic>L. robustum</italic>; the leaves of <italic>L. robustum</italic>, known as kudingcha (bitter tea), have long been used in China as an herbal tea for weight loss. Recently, based on previous studies, our team reached a preliminary conclusion that phenylpropanoid glycosides from <italic>L. robustum</italic> most likely contribute substantially to reducing lipid levels, but the mechanism remains unclear. Here, we conducted an <italic>in silico</italic> screen of currently known phenylethanoid glycosides from <italic>L. robustum</italic> and attempted to explore the hypolipidemic mechanism of ACT, the representative component of phenylethanoid glycosides in <italic>L. robustum</italic>, using RNA-seq technology, quantitative real-time PCR (qPCR) and Western blotting. First, the screening results for six compounds were docked with 15 human protein targets, and 3 of 15 protein targets were related to cardiovascular diseases. Based on previous experimental data and docking results, we selected ACT, which exerted positive effects, for further study. We generated a lipid accumulation model using HepG2 cells treated with a high concentration of oleic acid and then extracted RNA from cells treated for 24 h with 50 μmol/L ACT. Subsequently, we performed a transcriptomic analysis of the RNA-seq results, which revealed a large number of differentially expressed genes. Finally, we randomly selected some genes and proteins for further validation using qPCR and Western blotting; the results agreed with the RNA-seq data and confirmed their reliability. In conclusion, our experiments proved that ACT from <italic>L. robustum</italic> alters lipid metabolism and synthesis by regulating the expression of multiple genes, including <italic>Scarb1</italic>, <italic>Scarb2</italic>, <italic>Srebf1</italic>,<italic> Dhcr7</italic>, <italic>Acat2</italic>, <italic>Hmgcr</italic>, <italic>Fdft1</italic>, and <italic>Lss</italic>, which are involved several pathways, such as the glycolytic, AMPK, and fatty acid degradation pathways.</p>