Lycopene reduces cholesterol absorption through the downregulation of Niemann-Pick C1-like 1 in Caco-2 cells.
METHODS
Elevated blood cholesterol is an important risk factor associated with atherosclerosis and coronary heart disease. Tomato lycopene has been found to have a hypocholesterolemic effect, and the effect was considered to be related to inhibition of cholesterol synthesis. However, since plasma cholesterol levels are also influenced by the absorption of cholesterol in the gut, the present study is to investigate whether lycopene affects cholesterol absorption in the intestinal Caco-2 cells.


RESULTS
The Caco-2 cells were pretreated with lycopene at different concentrations for 24 h and then incubated with radioactive micellar cholesterol for 2 h. The absorption of radioactive cholesterol was quantified by liquid scintillation. The expression of Niemann-Pick C1-like 1 (NPC1L1) and liver X receptor α (LXRα) was analyzed by Western blot and qPCR. We found that lycopene dose dependently inhibited cholesterol absorption and the expression of NPC1L1 protein and NPC1L1 mRNA. The inhibitory effects of lycopene on cholesterol absorption and NPC1L1 expression could be prevented by blockade of the LXRα pathway.


CONCLUSIONS
This study provides the first evidence that lycopene inhibits cholesterol absorption in the intestinal cells and this inhibitory effect of lycopene is mediated, at least in part, by LXRα-NPC1L1 signaling pathway.
Department of Cardiology, Affiliated NanHai Hospital of Southern Medical University, Guangdong, P. R. China.
Jun
J
Zou
Guangdong Provincial Key Laboratory of Food Nutrition and Health, Department of Preventive Medicine, School of Public Health, Sun Yat-Sen University, Guangzhou, P. R. China.
Dan
D
Feng
D018938:Caco-2 Cells; D002338:Carotenoids / Q000494:pharmacology*; D002784:Cholesterol / Q000378:metabolism*; D015536:Down-Regulation; D006801:Humans; D007408:Intestinal Absorption / Q000187:drug effects*; D000071518:Liver X Receptors / Q000502:physiology; D000077276:Lycopene; D008565:Membrane Proteins / Q000037:antagonists & inhibitors* / Q000502:physiology; D026901:Membrane Transport Proteins; D015398:Signal Transduction / Q000502:physiology
D000071518:Liver X Receptors; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; C410800:NPC1L1 protein, human; D002338:Carotenoids; D002784:Cholesterol; D000077276:Lycopene
Caco-2 cells; Cholesterol; Liver X receptor α; Lycopene; NPC1L1 protein