Effect of a coffee lipid (cafestol) on regulation of lipid metabolism in CaCo-2 cells.
The influence of cafestol, a lipid component found in boiled coffee, on low density lipoprotein (LDL) and lipid metabolism was investigated in CaCo-2 cells cultured on filter membranes. The rate of uptake and degradation of 125I-labeled tyramine cellobiose-LDL was increased 50% in CaCo-2 cells incubated with cafestol (20 micrograms/ml, 63 microM) for 24 h, whereas in cells incubated with 25-hydroxycholesterol (10 micrograms/ml, 25 microM) the rate of uptake and degradation showed a 30% decrease. A mixture of kahweol and cafestol, both natural components of coffee beans, modestly enhanced the rate of LDL uptake and degradation, as compared to pure cafestol. Incubation of cafestol with CaCo-2 cells induced a 3-fold up-regulation of LDL receptor mRNA, as compared to control cells. In contrast, incubation of the cells with 25-hydroxycholesterol produced a 30% decrease of LDL receptor expression. CaCo-2 cells were transfected with a promoter region containing the sterol regulatory element-1 (SRE-1) coupled to the reporter gene chloramphenicol acetyltransferase (CAT). When cells transfected with SRE-1 promoter were incubated with cafestol, there was a 20% up-regulation of CAT activity, whereas 25-hydroxycholesterol abolished this activity. Cafestol contributed to a significantly lowered secretion of cholesteryl ester and triacylglycerol, regardless of the radiolabeled precursor used ([2-14C]acetic acid, [1,2,3-3H]glycerol, [3H]water, and [1-14C]oleic acid). This reduction in secretion of lipids was accompanied by an increase in trichloroacetic acid-soluble activity when radiolabeled oleic acid was used as a tracer. We conclude that cafestol promotes an enhanced rate of uptake and degradation of LDL, probably due to an increase in transcription of LDL receptor mRNA and a reduced secretion of cholesteryl ester and triacylglycerol in CaCo-2 cells.
Ranheim
T
T
Section for Dietary Research, University of Oslo, Norway.
Halvorsen
B
B
Huggett
A C
AC
Blomhoff
R
R
Drevon
C A
CA
D002460:Cell Line; D015500:Chloramphenicol O-Acetyltransferase / Q000235:genetics; D002784:Cholesterol / Q000096:biosynthesis* / Q000378:metabolism; D004224:Diterpenes / Q000737:chemistry / Q000494:pharmacology*; D006801:Humans; D006888:Hydroxycholesterols / Q000494:pharmacology*; D007422:Intestines / Q000166:cytology / Q000187:drug effects*; D050356:Lipid Metabolism; D008077:Lipoproteins, LDL / Q000378:metabolism; D015394:Molecular Structure; D019301:Oleic Acid; D009829:Oleic Acids / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis; D011973:Receptors, LDL / Q000032:analysis* / Q000235:genetics; D014280:Triglycerides / Q000378:metabolism
D004224:Diterpenes; D006888:Hydroxycholesterols; D008077:Lipoproteins, LDL; D009829:Oleic Acids; D012333:RNA, Messenger; D011973:Receptors, LDL; D014280:Triglycerides; D019301:Oleic Acid; C007997:25-hydroxycholesterol; D002784:Cholesterol; C053400:cafestol; D015500:Chloramphenicol O-Acetyltransferase