• Molecules and Cells
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• 제26권4호
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• pp.409-414
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• 2008

The cholesteryl ester transfer protein (CETP), a key player in cholesterol metabolism, has been shown to promote the transfer of triglycerides from very low density lipoprotein (VLDL) and low density lipoprotein (LDL) to high density lipoprotein (HDL) in exchange for cholesterol ester. Here we demonstrate that farnesoid X receptor ${\alpha}$ ($FXR{\alpha}$; NR1H4) down-regulates CETP expression in HepG2 cells. A $FXR{\alpha}$ ligand, chenodeoxycholic acid (CDCA), suppressed basal mRNA levels of the CETP gene in HepG2 cells in a dose-dependent manner. Using gel shift and chromatin immunoprecipitation (ChIP) assays, we found that $FXR{\alpha}$ could bind to the liver X receptor ${\alpha}$ ( $LXR{\alpha}$; NR1H3) binding site (LXRE; DR4RE) located within the CETP 5' promoter region. $FXR{\alpha}$ suppressed $LXR{\alpha}$-induced DR4RE-luciferase activity and this effect was mediated by a binding competition between $FXR{\alpha}$ and $LXR{\alpha}$ for DR4RE. Furthermore, the addition of CDCA together with a $LXR{\alpha}$ ligand, GW3965, to HepG2 cells was shown to substantially decrease mRNA levels of hepatic CETP gene, which is typically induced by GW3965. Together, our data demonstrate that $FXR{\alpha}$ down-regulates CETP gene expression via binding to the DR4RE sequence within the CETP 5' promoter and this $FXR{\alpha}$ binding is essential for $FXR{\alpha}$ inhibition of $LXR{\alpha}$-induced CETP expression.

• Journal of Microbiology and Biotechnology
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• 제23권3호
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• pp.322-328
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• 2013

In this study, we show the expression and purification of the human recombinant farnesoid X receptor (FXR)- ligand binding domain (LBD) protein in E. coli using a double cistronic vector, pACYCDuet-1, as a soluble form. We describe here the expression and characterization of a biologically active $FXR-LBD_{(248-476)}$. When expressed in the influence of bacterial promoters ($P_{T7}$ and $P_{Tac}$) of the single cistronic expression vectors, the human recombinant $FXR-LBD_{(248-476)}$ was found to be totally insoluble. However, by using a double cistronic expression vector, we were able to obtain the human recombinant $FXR-LBD_{(248-476)}$ in a soluble form. To allow for biological activities, we have subcloned into the pACYCDuet-1 vector, expressed in E. coli cells at some optimized conditions, and purified and characterized the human recombinant active $FXR-LBD_{(248-476)}$ proteins using the fluorescence polarization assay. This suggests that the expression of FXR-LBD in a double cistronic vector improves its solubility and probably assists its correct folding for the biologically active form of the proteins. We suggest that this may represent a new approach to high expression of other nuclear receptors and may be useful as well for other classes of heterodimeric protein partners.

• 대한약학회:학술대회논문집
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• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
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• pp.346.1-346.1
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• 2002

FXR (farnesoid X-activated receptor) is a member of nuclear steroid hormone receptor superfamily and especially a orphan receptor, which are able to control mevalonate pathway upon activation by binding of the specific ligands. We. have launched our study for development of FXR specific ligands getting on in lead discovery. A promising lead stilbene analog was obtained through the screening of a set of library compounds which was previously targeted for other nuclear receptors. And then synthetic modilication of the lead was perfoumde. In addition. fishing a new pharmacophore was fried by UNITT aearch. which brought new structural features.

• Laboraroty Animal Research
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• 제34권4호
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• pp.140-146
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• 2018

Though bile acids have been well known as digestive juice, recent studies have demonstrated that bile acids bind to their endogenous receptors, including Farnesoid X receptor (FXR) and G protein-coupled bile acid receptor 1 (GPBAR1; TGR5) and serve as hormone to control various biological processes, including cholesterol/bile acid metabolism, glucose/lipid metabolism, immune responses, and energy metabolism. Deficiency of those bile acid receptors has been reported to induce diverse metabolic syndromes such as obesity, hyperlipidemia, hyperglycemia, and insulin resistance. As consistent, numerous studies have reported alteration of bile acid signaling pathways in type II diabetes patients. Interestingly, bile acids have shown to activate TGR5 in intestinal L cells and enhance secretion of glucagon-like peptide 1 (GLP-1) to potentiate insulin secretion in response to glucose. Moreover, FXR has been shown to crosstalk with TGR5 to control GLP-1 secretion. Altogether, bile acid receptors, FXR and TGR5 are potent therapeutic targets for the treatment of metabolic diseases, including type II diabetes.

• 생명과학회지
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• 제21권4호
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• pp.481-485
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• 2011

T0901317은 핵수용체 전사인자인 liver X receptor (LXR, NR1H2/3)의 강력한 합성 리간드이다. 그러나, T0901317은 farnesoid X receptor (FXR, NR1H4)와 pregnane X receptor (PXR, NR1I2)에 대해 작용물질(agonist) 로, androgen receptor (AR, NR3C4)와 rertinoid-related orphan receptor-${\alpha}$ (ROR-${\alpha}$, NR1F1)에 대해 길항제(antagonist)로 작용하여, LXR외에 적어도 다른 4종의 핵수용체에 대해 그 활성을 조절한다고 보고되었다. 우리는 T0901317이 또 다른 핵수용체인 constitutive androstane receptor (CAR, NR1I3)에 대해 저해제로 기능함을 확인 하였다. CAR는 이미 T0901317에 의해 기능이 조절된다고 알려진 PXR, FXR, LXR과 더불어 간에서 생체이물과 콜레스테롤의 대사작용에 중요한 역할을 하므로 T0901317에 의해 CAR의 활성이 조절된다는 사실은, 간세포에서 T0901317을 이용한 실험 결과를 해석할 때 세포 내에 이미 존재하는 이들 핵수용체 단백질의 영향을 고려하여 주의깊게 해석해야 함을 의미한다.

• Experimental and Molecular Medicine
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• 제50권11호
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• pp.14.1-14.14
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• 2018

The link between antibiotic treatment and IF-associated liver disease (IFALD) is unclear. Here, we study the effect of antibiotic treatment on bile acid (BA) metabolism and investigate the involved mechanisms. The results showed that pediatric IF patients with cholestasis had a significantly lower abundance of BA-biotransforming bacteria than patients without cholestasis. In addition, the BA composition was altered in the serum, feces, and liver of pediatric IF patients with cholestasis, as reflected by the increased proportion of primary BAs. In the ileum, farnesoid X receptor (FXR) expression was reduced in patients with cholestasis. Correspondingly, the serum FGF19 levels decreased significantly in patients with cholestasis. In the liver, the expression of the rate-limiting enzyme in bile salt synthesis, cytochrome P450 7a1 (CYP7A1), increased noticeably in IF patients with cholestasis. In mice, we showed that oral antibiotics (gentamicin, GM or vancomycin, VCM) reduced colonic microbial diversity, with a decrease in both Gram-negative bacteria (GM affected Eubacterium and Bacteroides) and Gram-positive bacteria (VCM affected Clostridium, Bifidobacterium and Lactobacillus). Concomitantly, treatment with GM or VCM decreased secondary BAs in the colonic contents, with a simultaneous increase in primary BAs in plasma. Moreover, the changes in the colonic BA profile especially that of tauro-beta-muricholic acid ($T{\beta}MCA$), were predominantly associated with the inhibition of the FXR and further altered BA synthesis and transport. In conclusion, the administration of antibiotics significantly decreased the intestinal microbiota diversity and subsequently altered the BA composition. The alterations in BA composition contributed to cholestasis in IF patients by regulating FXR signaling.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 2002년도 창립10주년기념 및 국립독성연구원 의약품동등성평가부서 신설기념 국재학술대회:생물학적 동등성과 의약품 개발 전략을 위한 국제심포지움
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• pp.197-197
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• 2002

• Nutrition Research and Practice
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• 제10권5호
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• pp.501-506
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• 2016

BACKGROUNG/OBJECTIVES: Corn silk (CS) extract contains large amounts of maysin, which is a major flavonoid in CS. However, studies regarding the effect of CS extract on cholesterol metabolism is limited. Therefore, the purpose of this study was to determine the effect of CS extract on cholesterol metabolism in C57BL/6J mouse fed high-fat diets. MATERIALS/METHODS: Normal-fat group fed 7% fat diet, high-fat (HF) group fed 25% fat diet, and high-fat with corn silk (HFCS) group were orally administered CS extract (100 mg/kg body weight) daily. Serum and hepatic levels of total lipids, triglycerides, and total cholesterol as well as serum free fatty acid, glucose, and insulin levels were determined. The mRNA expression levels of acyl-CoA: cholesterol acyltransferase (ACAT), cholesterol 7-alpha hydroxylase (CYP7A1), farnesoid X receptor (FXR), lecithin cholesterol acyltransferase (LCAT), low-density lipoprotein receptor, 3-hyroxy-3-methylglutaryl-coenzyme A reductase (HMG-CoA reductase), adiponectin, leptin, and tumor necrosis factor ${\alpha}$ were determined. RESULTS: Oral administration of CS extract with HF improved serum glucose and insulin levels as well as attenuated HF-induced fatty liver. CS extracts significantly elevated mRNA expression levels of adipocytokines and reduced mRNA expression levels of HMG-CoA reductase, ACAT, and FXR. The mRNA expression levels of CYP7A1 and LCAT between the HF group and HFCS group were not statistically different. CONCLUSIONS: CS extract supplementation with a high-fat diet improves levels of adipocytokine secretion and glucose homeostasis. CS extract is also effective in decreasing the regulatory pool of hepatic cholesterol, in line with decreased blood and hepatic levels of cholesterol though modulation of mRNA expression levels of HMG-CoA reductase, ACAT, and FXR.

• Journal of Microbiology and Biotechnology
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• 제26권3호
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• pp.483-487
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• 2016

The triglyceride-lowering effect of probiotics Lactobacillus plantarum KY1032 and Lactobacillus curvatus HY7601 were investigated. Male SD Wistar rats were randomly divided into three groups and fed high-fat diet (HFD), HFD and probiotics (5 × 10⁹ CFU/day of L. plantarum KY1032 and 5 × 10⁹ CFU/day of L. curvatus HY7601), or normal diet for 6 weeks. Probiotic treatment significantly lowered the elevated plasma triglyceride and increased plasma free fatty acid, glycerol, and plasma apolipoprotein A-V (ApoA-V) levels. The probiotic-treated group showed elevated hepatic mRNA expression of PPARα, bile acid receptor (FXR), and ApoA-V. These results demonstrate that L. plantarum KY1032 and L. curvatus HY7601 lower triglycerides in hypertriglyceridemic rats by upregulating ApoA-V, PPARα, and FXR.

• BMB Reports
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• 제31권5호
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• pp.419-426
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• 1998

The nuclear hormone receptor superfamily currently includes approximately equal numbers of conventional receptors and orphan receptors, which do not have known ligands. Here, we review recent progress from this laboratory on three orphans, two of which are moving from orphan to conventional receptor status. Perhaps the most unusual is CAR, which is a constitutive transactivator in the absence of ligands but becomes transcriptionally inactive in the presence of its ligands, which are androgen metabolites. The response of CAR to its ligands is thus opposite to that of the conventional receptor paradigm. RIP14 (also known as FXR) is activated by both all-trans retinoic acid and a synthetic retinoid previously thought to specifically target the retinoic acid receptors (RARs), and thus appears to be a novel retinoid receptor. Finally, SHP is a novel orphan that lacks a DNA binding domain and interacts with a number of other receptor superfamily members. While it generally inhibits its targets, including CAR, the retinoid X receptor (RXR), and the estrogen receptor (ER), it stimulates transactivation by the orphan SF-1.