Advanced

Curcumin inhibits cholesterol uptake in Caco-2 cells by down-regulation of NPC1L1 expression

Feng, Dan LU ; Ohlsson, Lena LU and Duan, Rui-Dong LU (2010) In Lipids in Health and Disease 9.
Abstract
Background: Curcumin is a polyphenol and the one of the principle curcuminoids of the spice turmeric. Its antioxidant, anti-cancer and anti-inflammatory effects have been intensively studied. Previous in vivo studies showed that administration of curcumin also decreased cholesterol levels in the blood, and the effects were considered to be related to upregulation of LDL receptor. However, since plasma cholesterol levels are also influenced by the uptake of cholesterol in the gut, which is mediated by a specific transporter Niemann-Pick Cl-like 1 (NPC1L1) protein, the present study is to investigate whether curcumin affects cholesterol uptake in the intestinal Caco-2 cells. Methods: Caco-2 cells were cultured to confluence. The micelles... (More)
Background: Curcumin is a polyphenol and the one of the principle curcuminoids of the spice turmeric. Its antioxidant, anti-cancer and anti-inflammatory effects have been intensively studied. Previous in vivo studies showed that administration of curcumin also decreased cholesterol levels in the blood, and the effects were considered to be related to upregulation of LDL receptor. However, since plasma cholesterol levels are also influenced by the uptake of cholesterol in the gut, which is mediated by a specific transporter Niemann-Pick Cl-like 1 (NPC1L1) protein, the present study is to investigate whether curcumin affects cholesterol uptake in the intestinal Caco-2 cells. Methods: Caco-2 cells were cultured to confluence. The micelles composed of bile salt, monoolein, and C-14-cholesterol were prepared. We first incubated the cells with the micelles in the presence and absence of ezetimibe, the specific inhibitor of NPC1L1, to see whether the uptake of the cholesterol in the cells was mediated by NPC1L1. We then pretreated the cells with curcumin at different concentrations for 24 h followed by examination of the changes of cholesterol uptake in these curcumin-treated cells. Finally we determined whether curcumin affects the expression of NPC1L1 by both Western blot analysis and qPCR quantification. Results: We found that the uptake of radioactive cholesterol in Caco-2 cells was inhibited by ezetimibe in a dose-dependent manner. The results indicate that the uptake of cholesterol in this study was mediated by NPC1L1. We then pretreated the cells with 25-100 mu M curcumin for 24 h and found that such a treatment dose-dependently inhibited cholesterol uptake with 40% inhibition obtained by 100 mu M curcumin. In addition, we found that the curcumin-induced inhibition of cholesterol uptake was associated with significant decrease in the levels of NPC1L1 protein and NPC1L1 mRNA, as analyzed by Western blot and qPCR, respectively. Conclusion: Curcumin inhibits cholesterol uptake through suppression of NPC1L1 expression in the intestinal cells. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Lipids in Health and Disease
volume
9
publisher
BioMed Central
external identifiers
  • wos:000277513700001
  • scopus:77950955510
ISSN
1476-511X
DOI
10.1186/1476-511X-9-40
language
English
LU publication?
yes
id
9bc923ba-3fee-414f-932d-53794423e355 (old id 1618394)
alternative location
http://www.lipidworld.com/content/9/1/40
date added to LUP
2010-06-22 09:50:09
date last changed
2018-07-15 03:46:27
@article{9bc923ba-3fee-414f-932d-53794423e355,
  abstract     = {Background: Curcumin is a polyphenol and the one of the principle curcuminoids of the spice turmeric. Its antioxidant, anti-cancer and anti-inflammatory effects have been intensively studied. Previous in vivo studies showed that administration of curcumin also decreased cholesterol levels in the blood, and the effects were considered to be related to upregulation of LDL receptor. However, since plasma cholesterol levels are also influenced by the uptake of cholesterol in the gut, which is mediated by a specific transporter Niemann-Pick Cl-like 1 (NPC1L1) protein, the present study is to investigate whether curcumin affects cholesterol uptake in the intestinal Caco-2 cells. Methods: Caco-2 cells were cultured to confluence. The micelles composed of bile salt, monoolein, and C-14-cholesterol were prepared. We first incubated the cells with the micelles in the presence and absence of ezetimibe, the specific inhibitor of NPC1L1, to see whether the uptake of the cholesterol in the cells was mediated by NPC1L1. We then pretreated the cells with curcumin at different concentrations for 24 h followed by examination of the changes of cholesterol uptake in these curcumin-treated cells. Finally we determined whether curcumin affects the expression of NPC1L1 by both Western blot analysis and qPCR quantification. Results: We found that the uptake of radioactive cholesterol in Caco-2 cells was inhibited by ezetimibe in a dose-dependent manner. The results indicate that the uptake of cholesterol in this study was mediated by NPC1L1. We then pretreated the cells with 25-100 mu M curcumin for 24 h and found that such a treatment dose-dependently inhibited cholesterol uptake with 40% inhibition obtained by 100 mu M curcumin. In addition, we found that the curcumin-induced inhibition of cholesterol uptake was associated with significant decrease in the levels of NPC1L1 protein and NPC1L1 mRNA, as analyzed by Western blot and qPCR, respectively. Conclusion: Curcumin inhibits cholesterol uptake through suppression of NPC1L1 expression in the intestinal cells.},
  author       = {Feng, Dan and Ohlsson, Lena and Duan, Rui-Dong},
  issn         = {1476-511X},
  language     = {eng},
  publisher    = {BioMed Central},
  series       = {Lipids in Health and Disease},
  title        = {Curcumin inhibits cholesterol uptake in Caco-2 cells by down-regulation of NPC1L1 expression},
  url          = {http://dx.doi.org/10.1186/1476-511X-9-40},
  volume       = {9},
  year         = {2010},
}