Lycopene absorption in human intestinal cells and in mice involves scavenger receptor class B type I but not Niemann-Pick C1-like 1

J Nutr. 2008 Aug;138(8):1432-6. doi: 10.1093/jn/138.8.1432.

Abstract

Cholesterol membrane transporters scavenger receptor class B type I (SR-BI) and (cluster determinant 36) are involved in intestinal uptake of lutein and beta-carotene, 2 of the 3 main carotenoids of the human diet. The aim of this work was therefore to determine whether SR-BI and NPC1L1 (Niemann-Pick C1-like 1), another cholesterol transporter, are implicated in absorption of lycopene, the 3rd main carotenoid of the human diet. Anti-human SR-BI antibody and block lipid transport 1 (BLT1) (a chemical inhibitor of lipid transport by SR-BI) impaired up to 60% (all-E) and (5Z)-lycopene uptake (P < 0.05) by Caco-2 cell monolayers, which were used as a model of human intestinal epithelium. The involvement of SR-BI in lycopene absorption in vivo was then verified by comparing plasma lycopene concentrations in wild-type and SR-BI transgenic mice that were fed a diet enriched with 0.25 g/kg (all-E)-lycopene for 1 mo. Plasma lycopene concentrations were approximately 10-fold higher (P < 0.001) in mice overexpressing SR-BI in the intestine than in wild-type mice, confirming the involvement of SR-BI in lycopene absorption. Further experiments showed that (all-E)-lycopene did not affect SR-BI mRNA levels in Caco-2 cells or mouse intestine. In contrast to SR-BI, neither anti-human NPC1L1 antibody nor ezetimibe, used as inhibitors of lycopene uptake via NPC1L1, significantly impaired (all-E) or (5Z)-lycopene uptake by Caco-2 monolayers. Thus, the present data show that lycopene absorption is, at least in part, mediated by SR-BI but not by NPC1L1.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anticholesteremic Agents / pharmacology
  • Azetidines / pharmacology
  • Biological Availability
  • Caco-2 Cells
  • Carotenoids / metabolism
  • Carotenoids / pharmacokinetics*
  • Carotenoids / pharmacology
  • Diet
  • Ezetimibe
  • Gene Expression Regulation / drug effects
  • Humans
  • Intestinal Absorption / physiology
  • Intestinal Mucosa / metabolism*
  • Intestines / cytology*
  • Intestines / drug effects
  • Lycopene
  • Male
  • Membrane Proteins / antagonists & inhibitors
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism*
  • Membrane Transport Proteins
  • Mice
  • Mice, Transgenic
  • Nutritional Physiological Phenomena
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Scavenger Receptors, Class B / antagonists & inhibitors
  • Scavenger Receptors, Class B / genetics
  • Scavenger Receptors, Class B / metabolism*

Substances

  • Anticholesteremic Agents
  • Azetidines
  • Membrane Proteins
  • Membrane Transport Proteins
  • NPC1L1 protein, human
  • RNA, Messenger
  • SCARB1 protein, human
  • Scarb1 protein, mouse
  • Scavenger Receptors, Class B
  • Carotenoids
  • Ezetimibe
  • Lycopene