Xanthohumol Suppresses NPC1L1 Gene Expression through Downregulation of HNF-4α and Inhibits Cholesterol Uptake in Caco-2 Cells

Abstract

Xanthohumol (Xan) is a prenylated chalcone mainly found in hops; it has been demonstrated to function against hypercholesterolemia, hyperlipidemia, and atherosclerosis. In this study, we focused on the hypocholesterolemic effect of Xan on cholesterol uptake and the underlying molecular mechanisms of Xan in human intestinal Caco-2 cells. The microarray data showed that Niemann−Pick C1-like 1 (NPC1L1), an essential transporter for dietary cholesterol absorption, was significantly downregulated in Xan-treated Caco-2 cells. We demonstrated that Xan (10 and 20 μM) suppressed the mRNA and protein expression of NPC1L1 by 0.65 ± 0.12-fold and 0.54 ± 0.15-fold and 0.72 ± 0.04-fold and 0.44 ± 0.12-fold, respectively, compared to that of the vehicle-treated Caco-2 cells. Moreover, Xan (10 and 20 μM) significantly inhibited cholesterol uptake by approximately 12 and 32% in Caco-2 cells. NPC1L1 promoter activity was significantly suppressed by Xan, and a DNA element within the NPC1L1 promoter involved in Xan-mediated NPC1L1 reduction located between the −120 and −20 positions was identified. Moreover, Xan markedly decreased the mRNA and protein levels of hepatocyte nuclear factor 4α (HNF-4α), a critical activator of NPC1L1 transcription, and subsequently attenuated HNF-4α/NPC1L1 promoter complex formation, resulting in the suppression of NPC1L1 gene expression. Finally, we demonstrated that Xan markedly abolished lovastatin-induced NPC1L1 overexpression in Caco-2 cells. These findings reveal that Xan suppresses NPC1L1 expression via downregulation of HNF-4α and exerts inhibitory effects on cholesterol uptake in the intestinal Caco-2 cells. Our findings suggest Xan could serve as a potential cholesterol-lowering agent and supplement for statin therapy.

Food Chemistry of Selenium and Controversial Roles of Selenium in Affecting Blood Cholesterol Concentrations

“…Dietary intake and biliary secretion are the major sources of luminal cholesterol (Figure ). First, free cholesterol in the intestinal lumen is transported into the enterocytes by Niemann-Pick C1-like 1 protein (NPC1L1) localized in the brush border membrane . Cholesterol absorption varies between 29 and 80% in the small intestine; therefore, NPC1L1 represents a drug target of cholesterol absorption inhibitors to prevent hypercholesterolemia .…”

“…First, free cholesterol in the intestinal lumen is transported into the enterocytes by Niemann-Pick C1-like 1 protein (NPC1L1) localized in the brush border membrane. 55 Cholesterol absorption varies between 29 and 80% in the small intestine; therefore, NPC1L1 represents a drug target of cholesterol absorption inhibitors to prevent hypercholesterolemia. 56 Second, acetyl-CoA acyltransferase 2 (ACAT2) converts free cholesterol into cholesteryl ester (CE) in the endoplasmic reticulum (ER), which is then packaged into chylomicrons by microsomal triacylglycerol transport protein (MTP) and absorbed into blood through the lymphatic system.…”

The roles of nuclear receptors in cholesterol metabolism and reverse cholesterol transport in nonalcoholic fatty liver disease

“… 158 A decrease in HNF4α levels can inhibit the expression of NPC1L1 in Caco-2 cells and inhibit the uptake of cholesterol by cells. 159 ApoA-1 is the main carrier protein of HDL and exerts atherosclerosis protective properties by participating in the ABCA1 and ABCG1 pathways involved in RCT. 160 , 161 ApoA-1-defective mice do not form normal HDL particles and cannot effectively transport cholesterol to liver tissue, leading to cardiovascular diseases such as atherosclerosis.…”

Bioavailability and Cardiometabolic Effects of Xanthohumol: Evidence from Animal and Human Studies

“…[70] In Caco-2 cells, xanthohumol inhibited the expression of the cholesterol transporter Niemann-Pick C1like 1 through downregulation of hepatocyte nuclear factor 4𝛼, and reduced cholesterol uptake. [81] Xanthohumol furthermore increases the number of LDL receptors on the surface of HepG2 cells and enhances LDL uptake by interfering with the liver X receptor (LXR), which results in reduced expression of the inducible degrader of the LDL receptor. [82] In another model using HepG2 cells, xanthohumol activated farnesoid X receptor (FXR), a nuclear hormone receptor involved in the regulation of lipid and lipoprotein metabolism.…”