Epigallocatechin gallate induces an up-regulation of LDLR accompanied by a reduction of idol in Hepg2 cells

Abstract

AbstractEpigallocatechin gallate (EGCG), the primary catechin in green tea, has improved cholesterol metabolism. However, the molecular mechanisms of EGCG underlying these functions are not fully understood. In this study, we aimed to investigate the molecular mechanisms underlying EGCG’s effect on low-density lipoprotein (LDL) in HepG2 cells. Real-time PCR and Western blot analysis were used to determine the mRNA and protein levels in the human hepatoma cell line (HepG2). LDL uptake assay was used to quantify the low-density lipoprotein receptor (LDLR) function. EGCG induced significantly up-regulated LDLR protein and mRNA levels in HepG2 cells (P < 0.05). Both at the transcriptional level and at the protein level, EGCG can significantly (P < 0.05) down-regulate the elevated expression levels of liver X receptor α (LXRα) and inducible degrader of the LDLR (Idol) due to 25-OHC. Fluorescence results showed that EGCG induction could also significantly increase LDL uptake (P < 0.05). EGCG regulates LDL uptake through the LXRα-LDLR pathway, and EGCG can effectively improve the abnormal expression of protein and mRNA induced by 25-OHC. Graphical abstract