Lowbush blueberries inhibit scavenger receptors CD36 and SR-A expression and attenuate foam cell formation in ApoE-deficient mice

Food Funct. 2011 Oct;2(10):588-94. doi: 10.1039/c1fo10136f. Epub 2011 Sep 28.

Abstract

Blueberries have recently been reported to reduce atherosclerotic lesion progression in apoE deficient (apoE(-/-)) mice. However, the underlying mechanisms are not fully understood. The objective of this study was to determine whether lowbush blueberries altered scavenger receptor expression and foam cell formation in apoE(-/-) mice. ApoE(-/-) mice were fed AIN-93 diet (CD) or CD formulated to contain 1% freeze-dried lowbush blueberries (BB) for 20 weeks. Gene expression and protein levels of scavenger receptor CD36 and SR-A in aorta and thioglycollate-elicited peritoneal macrophages (PM) were lower in mice fed BB (P < 0.05). In the second experiment, apoE(-/-) mice were fed CD or BB for 5 weeks. PM were collected and cultured. Gene expression and protein levels of CD36 and SR-A were found to be lower in PM of BB fed mice (P < 0.05). In PM from BB fed mice, fewer oxLDL-induced foam cells were formed compared to those from mice fed CD. Gene expression and protein levels of PPARγ were lower in the PM of BB fed mice (P < 0.05). Detectable isomers of hydroxyoctadecadienoic acids (HODEs) and hydroxyeicosatetraenoic acid (HETEs) were also lower in the PM of BB fed mice (P < 0.05 or P < 0.01). In conclusion, BB inhibited expression of the two major scavenger receptors CD36 and SR-A in PM of apoE(-/-) mice, at least in part through down-regulating PPARγ and reducing its endogenous ligands HODEs and HETEs. We proposed that BB mediated reduction of scavenger receptor expression and attenuation of oxLDL-induced foam cell formation in PM of apoE(-/-) mice are important mechanisms of the athero-protective effects of BB.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apolipoproteins E / deficiency*
  • Apolipoproteins E / genetics
  • Atherosclerosis / drug therapy*
  • Atherosclerosis / genetics*
  • Atherosclerosis / metabolism
  • Blueberry Plants / chemistry*
  • CD36 Antigens / genetics*
  • CD36 Antigens / metabolism
  • Down-Regulation / drug effects*
  • Female
  • Foam Cells / cytology*
  • Foam Cells / drug effects
  • Foam Cells / metabolism
  • Gene Expression / drug effects
  • Humans
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • PPAR gamma / genetics
  • PPAR gamma / metabolism
  • Plant Preparations / administration & dosage*
  • Scavenger Receptors, Class A / genetics*
  • Scavenger Receptors, Class A / metabolism

Substances

  • Apolipoproteins E
  • CD36 Antigens
  • PPAR gamma
  • Plant Preparations
  • Scavenger Receptors, Class A