Quercetin induces the selective uptake of HDL-cholesterol via promoting SR-BI expression and the activation of the PPARγ/LXRα pathway

Food Funct. 2018 Jan 24;9(1):624-635. doi: 10.1039/c7fo01107e.

Abstract

Reverse cholesterol transport (RCT) is the process to deliver cholesterol to the liver for further excretion and involves scavenger receptor class B type I (SR-BI)-mediated selective lipid uptake (SLU) from high-density lipoprotein cholesterol (HDL-C). The up-regulation of hepatic SR-BI expression accelerates HDL-C clearance in circulation and impedes the development of atherosclerosis (AS). In the present study, we explored the modulation of hepatic SR-BI expression and SR-BI-mediated SLU by quercetin, a natural flavonoid compound in the diet with a favorable role in cardiovascular disorders. We found that quercetin significantly increased the expression level of SR-BI in HepG2 cells in a concentration- and time-dependent manner. Besides, quercetin had stimulatory effects on the binding of 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (Dil)-labeled HDL to hepatocytes and 125I/3H-CE-HDL association. Treatment with small interfering RNA (siRNA) or SR-BI specific inhibitor, BLT-1, inhibited quercetin-induced Dil-HDL binding and selective HDL-C uptake. Treatment with quercetin increased both proliferator-activated receptor γ (PPARγ) and liver X receptor α (LXRα) levels. Additionally, the quercetin-induced expression of SR-BI, Dil-HDL binding and the selective uptake of HDL-C were significantly attenuated by treatment with PPARγ siRNA, LXRα siRNA, and their antagonists, respectively. In C57BL/6 mice, quercetin administration potently increased SR-BI, PPARγ and LXRα levels and lipid accumulation in the liver. Altogether, our results suggest that quercetin-induced up-regulation of SR-BI and subsequent lipid uptake in hepatocytes might contribute to its beneficial effects on cholesterol homeostasis and atherogenesis.

MeSH terms

  • Animals
  • Atherosclerosis / drug therapy*
  • Atherosclerosis / genetics
  • Atherosclerosis / metabolism
  • Biological Transport / drug effects
  • CD36 Antigens / genetics
  • CD36 Antigens / metabolism*
  • Cholesterol, HDL / metabolism*
  • Humans
  • Liver / drug effects
  • Liver / metabolism
  • Liver X Receptors / genetics
  • Liver X Receptors / metabolism*
  • Male
  • Mice, Inbred C57BL
  • PPAR gamma / genetics
  • PPAR gamma / metabolism*
  • Quercetin / administration & dosage*

Substances

  • CD36 Antigens
  • Cholesterol, HDL
  • Liver X Receptors
  • PPAR gamma
  • Quercetin