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LXR Driven Induction of HDL-Cholesterol is Independent of Intestinal Cholesterol Absorption and ABCA1 Protein Expression
- Source :
- Lipids. 49:71-83
- Publication Year :
- 2013
- Publisher :
- Wiley, 2013.
-
Abstract
- We investigated whether: (1) liver X receptor (LXR)-driven induction of high-density lipoprotein cholesterol (HDL-C) and other LXR-mediated effects on cholesterol metabolism depend on intestinal cholesterol absorption; and (2) combined treatment with the LXR agonist GW3965 and the cholesterol absorption inhibitor ezetimibe results in synergistic effects on cholesterol metabolism that could be beneficial for treatment of atherosclerosis. Mice were fed 0.2 % cholesterol and treated with GW3965+ezetimibe, GW3965 or ezetimibe. GW3965+ezetimibe treatment elevated serum HDL-C and Apolipoprotein (Apo) AI, effectively reduced the intestinal cholesterol absorption and increased the excretion of faecal neutral sterols. No changes in intestinal ATP-binding cassette (ABC) A1 or ABCG5 protein expression were observed, despite increased mRNA expression, while hepatic ABCA1 was slightly reduced. The combined treatment caused a pronounced down-regulation of intestinal Niemann-Pick C1-like 1 (NPC1L1) and reduced hepatic and intestinal cholesterol levels. GW3965 did not affect the intestinal cholesterol absorption, but increased serum HDL-C and ApoAI levels. GW3965 also increased Apoa1 mRNA levels in primary mouse hepatocytes and HEPA1-6 cells. Ezetimibe reduced the intestinal cholesterol absorption, ABCA1 and ABCG5, but did not affect the serum HDL-C or ApoAI levels. Thus, the LXR-driven induction of HDL-C and ApoAI was independent of the intestinal cholesterol absorption and increased expression of intestinal or hepatic ABCA1 was not required. Inhibited influx of cholesterol via NPC1L1 and/or low levels of intracellular cholesterol prevented post-transcriptional expression of intestinal ABCA1 and ABCG5, despite increased mRNA levels. Combined LXR activation and blocked intestinal cholesterol absorption induced effective faecal elimination of cholesterol.
- Subjects :
- Male
Benzylamines
Gene Expression
Benzoates
Biochemistry
Intestinal absorption
Feces
Mice
chemistry.chemical_compound
Cholesterol absorption inhibitor
ATP Binding Cassette Transporter, Subfamily G, Member 5
Intestinal Mucosa
Cells, Cultured
Liver X Receptors
biology
Reverse Transcriptase Polymerase Chain Reaction
Anticholesteremic Agents
Reverse cholesterol transport
Orphan Nuclear Receptors
Intestines
Cholesterol
Liver
Intestinal cholesterol absorption
lipids (amino acids, peptides, and proteins)
ATP Binding Cassette Transporter 1
medicine.drug
medicine.medical_specialty
medicine.drug_class
Lipoproteins
Blotting, Western
Ezetimibe
Cell Line, Tumor
Internal medicine
medicine
Animals
Liver X receptor
Apolipoprotein A-I
Cholesterol, HDL
Organic Chemistry
Membrane Transport Proteins
Cell Biology
Mice, Inbred C57BL
Endocrinology
Intestinal Absorption
chemistry
ABCA1
Hepatocytes
biology.protein
Azetidines
ATP-Binding Cassette Transporters
Subjects
Details
- ISSN :
- 15589307 and 00244201
- Volume :
- 49
- Database :
- OpenAIRE
- Journal :
- Lipids
- Accession number :
- edsair.doi.dedup.....3aca2ea329ed1d16796fb8314ffffe2f