2005 Fiscal Year Final Research Report Summary
Regulation of bile acid metabolism by nuclear receptors
| Project/Area Number |
15390091
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
General medical chemistry
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| Research Institution | Nihon University (2004-2005)
Osaka University (2003) |
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Principal Investigator |
MAKISHIMA Makoto Nihon University, School of Medicine, Professor, 医学部, 教授 (70346146)
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| Project Period (FY) |
2003 – 2005
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| Keywords | nuclear receptor / bile acid / plant sterol / LXR / VDR / metabolism / transcription / cholestasis |
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| Research Abstract |
We investigated regulation of bile acid metabolism by nuclear receptors and its relation to lipid and vitamin metabolisms and found the following novel findings.
1.Identification of novel ligands
(1)By screening sterol compounds on activation of nuclear receptors, we found that plant sterol derivatives act as LXR ligands. An ergosterol derivative activated LXRα and LXRβ effectively and induced target gene expression selectively in intestine in mice.
(2)We investigated the structure-activity relationship between VDR and lithocholic acid and generated a docking model of lithocholic acid in VDR ligand-binding pocket. We found a novel VDR ligand, lithocholic acid acetate. It selectively activated VDR.
(3)By investigating the mechanism of activation of bile acid receptors, we found that an inhibitor of Na+, K+-ATPase enhances the ligand-dependent VDR activity.
(4)We examined the effect of several RXR ligands on activation of RXR heterodimers, because bile acid receptors, FXR,PXR and VDR, act as RXR heterodimers. We found a RXR ligand that selectively activates RXR heterodimers with orphan nuclear receptors, NGFI-B and Nurr1.
2.Gene transcription regulation
We investigated crosstalk between bile acid/lipid-sensing nuclear receptors and other transcription regulation systems, and found that LXR inhibited β-catenin-induced transcription. Since β-catenin is involved in proliferation of intestinal mucosal cells and colon carcinogenesis, LXR may mediate functional connection from dietary lipid signals and cell proliferation mechanism.
3.In vivo analysis
We generated a cholestasis model by bile duct ligation in mice, and examined expression of target genes of bile acid receptors, and found that expression of RANKL in kidney was increased. RANKL is a VDR target and is involved in bone metabolism. The data suggest a mechanism of cholestasis-induced abnormality in bone metabolism.
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Research Products
(18 results)
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[Journal Article] Selective activation of vitamin D receptor by lithocholic acid acetate, a bile acid derivative2005
Author(s)
Adachi, R., Honma, Y., Masuno, H., Kawana, K., Shimonura, I., Yamada, S., Makishima, M.
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Journal Title
Journal of Lipid Research 46
Pages: 46-57
Description
「研究成果報告書概要(欧文)」より
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[Journal Article] Enhancement of ligand-dependent vitamin D receptor transzctivaton by the cardiotonic steroid bufalin2005
Author(s)
Nakano, H., Matsunawa, M., Yasui, A., Adachi, R., Kawana, K., Shimonura, I., Makishima, M.
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Journal Title
Biochemical Pharmacology 70
Pages: 1479-1486
Description
「研究成果報告書概要(欧文)」より
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[Journal Article] Selective allosteric ligand activation of the retinoid X receptor heterodimaers of NGF-B and Nurr12005
Author(s)
Morita, K., Kawana, K., Sodeyama, M., Shimomura, I., Kagechika, H., Makishima, M.
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Journal Title
Biochemical Pharmacology 71
Pages: 98-107
Description
「研究成果報告書概要(欧文)」より
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[Journal Article] Structural determinants for vitamin D receptor response to endocrine and xenobiotic signals2004
Author(s)
Adachi, R., Shulman, A.I., Yamamoto, K., Shimomura, I., Yamada, S., Mangelsdorf, D.J., Makishima, M.
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Journal Title
Molecular Endocrinology 18
Pages: 23-52
Description
「研究成果報告書概要(欧文)」より
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[Journal Article] Induction of intetinal ATP-binding cassette transporters by a phytosterol-derived liver X receptor agonist2003
Author(s)
Kaneko, E., Matsuda, M., Yamada, Y., Tachibana, Y., Shimonura, I., Makishima, M.
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Journal Title
Journal of Biological Chemistry 278
Pages: 36091-36098
Description
「研究成果報告書概要(欧文)」より
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