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SHR Neuro Krebs Kardio Lipid

Chennamsetty, I; Claudel, T; Kostner, KM; Baghdasaryan, A; Kratky, D; Levak-Frank, S; Frank, S; Gonzalez, FJ; Trauner, M; Kostner, GM.
Farnesoid X receptor represses hepatic human APOA gene expression.
J Clin Invest. 2011; 121(9):3724-3734 [OPEN ACCESS]
Web of Science PubMed PUBMED Central FullText FullText_MUG

 

Autor/innen der Med Uni Graz:
Baghdasaryan Anna
Chennamsetty Indumathi
Claudel Thierry
Frank Saša
Kostner Gerhard
Kratky Dagmar
Levak Sanja
Trauner Michael
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Abstract:
High plasma concentrations of lipoprotein(a) [Lp(a), which is encoded by the APOA gene] increase an individual's risk of developing diseases, such as coronary artery diseases, restenosis, and stroke. Unfortunately, increased Lp(a) levels are minimally influenced by dietary changes or drug treatment. Further, the development of Lp(a)-specific medications has been hampered by limited knowledge of Lp(a) metabolism. In this study, we identified patients suffering from biliary obstructions with very low plasma Lp(a) concentrations that rise substantially after surgical intervention. Consistent with this, common bile duct ligation in mice transgenic for human APOA (tg-APOA mice) lowered plasma concentrations and hepatic expression of APOA. To test whether farnesoid X receptor (FXR), which is activated by bile acids, was responsible for the low plasma Lp(a) levels in cholestatic patients and mice, we treated tg-APOA and tg-APOA/Fxr-/- mice with cholic acid. FXR activation markedly reduced plasma concentrations and hepatic expression of human APOA in tg-APOA mice but not in tg-APOA/Fxr-/- mice. Incubation of primary hepatocytes from tg-APOA mice with bile acids dose dependently downregulated APOA expression. Further analysis determined that the direct repeat 1 element between nucleotides -826 and -814 of the APOA promoter functioned as a negative FXR response element. This motif is also bound by hepatocyte nuclear factor 4α (HNF4α), which promotes APOA transcription, and FXR was shown to compete with HNF4α for binding to this motif. These findings may have important implications in the development of Lp(a)-lowering medications.
Find related publications in this database (using NLM MeSH Indexing)
Animals -
Apolipoproteins A - genetics Apolipoproteins A - metabolism
Bile Acids and Salts - administration & dosage Bile Acids and Salts - blood
Cells, Cultured -
Female -
Gene Expression -
Hepatocyte Nuclear Factor 4 - genetics Hepatocyte Nuclear Factor 4 - metabolism
Humans -
Jaundice, Obstructive - blood
Liver - cytology Liver - physiology
Mice -
Mice, Knockout -
Mice, Transgenic -
Promoter Regions, Genetic -
RNA, Messenger - metabolism
Random Allocation -
Receptors, Cytoplasmic and Nuclear - genetics Receptors, Cytoplasmic and Nuclear - metabolism

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