Farnesoid X receptor (FXR) is a member of the nuclear receptor superfamily of ligand-activated transcription factors. As a metabolic regulator, FXR plays key roles in bile acid and cholesterol metabolism and lipid and glucose homeostasis. Therefore, FXR is a potential drug target for several metabolic syndromes, especially those related to lipidemia disorders. In the present study, we identified small molecule SIPI-7623, a derivative of an extract from Oriental wormwood (Artemisia capillaris), and found that it specifically upregulated the expression of cholesterol-7-alpha-hydroxylase (CYP7A1), downregulated the expression of sterol-regulatory element-binding protein 1c (SREBP-1c) in the liver, and inhibited the expression of ileal bile acid binding-protein (IBABP) in the ileum of rats. We found that inhibition of FXR by SIPI-7623 decreased the level of cholesterol and triglyceride. SIPI-7623 reduced the levels of cholesterol and triglyceride in in vitro HepG2 cell models, ameliorated diet-induced atherosclerosis, and decreased the serum lipid content on rats and rabbits model of atherosclerosis in vivo. Furthermore, SIPI-7623 decreased the extent of atherosclerotic lesions. Our resutls demonstrated that antagonism of the FXR pathway can be employed as a therapeutic strategy to treat metabolic diseases such as hyperlipidemia and atherosclerosis. In conclusion, SIPI-7623 could be a promising lead compound for development of drugs to treat hyperlipidemia and atherosclerosis.
Animals ; Artemisia ; chemistry ; Atherosclerosis ; drug therapy ; genetics ; metabolism ; Cholesterol ; metabolism ; Cholesterol 7-alpha-Hydroxylase ; genetics ; metabolism ; Drugs, Chinese Herbal ; administration & dosage ; Humans ; Hyperlipidemias ; drug therapy ; genetics ; metabolism ; Hypolipidemic Agents ; administration & dosage ; Liver ; drug effects ; metabolism ; Male ; Rabbits ; Rats ; Rats, Sprague-Dawley ; Receptors, Cytoplasmic and Nuclear ; antagonists & inhibitors ; genetics ; metabolism ; Sterol Regulatory Element Binding Protein 1 ; genetics ; metabolism ; Triglycerides ; metabolism

OBJECTIVEThis study aimed to investigate the expression pattern and function of Nuclear receptor subfamily 2 group E member 1 (Nr2e1) in retinoic acid (RA)-induced brain abnormality.

METHODSThe mouse model of brain abnormality was established by administering 28 mg/kg RA, and neural stem cells (NSCs) were isolated from the mouse embryo and cultured in vitro. Nr2e1 expression was detected by whole mount in situ hybridization, RT-PCR, and Western blotting. Nr2e1 function was determined by transducing Nr2e1 shRNA into NSCs, and the effect on the sonic hedgehog (Shh) signaling pathway was assessed in the cells. In addition, the regulation of Nr2e1 expression by RA was also determined in vitro.

RESULTSNr2e1 expression was significantly downregulated in the brain and NSCs of RA-treated mouse embryos, and knockdown of Nr2e1 affected the proliferation of NSCs in vitro. In addition, a similar expression pattern of Nr2e1 and RA receptor (RAR) α was observed after treatment of NSCs with different concentrations of RA.

CONCLUSIONOur study demonstrated that Nr2e1 could be regulated by RA, which would aid a better understanding of the mechanism underlying RA-induced brain abnormality.

Animals ; Brain ; cytology ; embryology ; Cell Proliferation ; Down-Regulation ; Gene Expression Regulation ; Gene Expression Regulation, Developmental ; drug effects ; Mice ; Mice, Inbred C57BL ; Neural Stem Cells ; drug effects ; physiology ; Receptors, Cytoplasmic and Nuclear ; genetics ; metabolism ; Tretinoin ; pharmacology

OBJECTIVETo study the effect of total flavonoids of Astmgali Radix (TFA) on liver cirrhosis induced with dimethylnitrosamine (DMN) in rats, and the effect on peroxisome proliferator-activated receptor γ (PPARγ), uncoupling protein 2 (UCP2) and farnesoid X receptor (FXR).

METHODSFifty-three Sprague-Dawley rats were randomly divided into a control group (10 rats) and a DMN group (43 rats). Rats in the DMN group were given DMN for 4 weeks and divided randomly into a model group (14 rats), a low-dosage TFA group (14 rats) and a high-dosage TFA group (15 rats) in the 3rd week. Rats were given TFA for 4 weeks at the dosage of 15 and 30 mg/kg in the low- and high-TFA groups, respectively. At the end of the experiment blood and liver samples were collected. Serum liver function and liver tissue hydroxyproline content were determined. hematoxylin-eosin (HE), Sirus red and immunohistochemical stainings of collagen I, smooth muscle actin (α-SMA) was conducted in paraffinembedded liver tissue slices. Real time polymerase chain reaction (PCR) was adopted to determine PPARγ, UCP2 and FXR mRNA levels. Western blot was adopted to determine protein levels of collagen I, α-SMA, PPARγ, UCP2 and FXR.

RESULTSCompared with the model group, TFA increased the ratio of liver/body weight (low-TFA group P<0.05, high-TFA group P<0.01), improved liver biochemical indices (P<0.01 for ALT, AST, GGT in both groups, P<0.05 for albumin and TBil in the high-TFA group) and reduced liver tissue hydroxproline content (P<0.01 in both groups) in treatment groups significantly. HE staining showed that TFA alleviated liver pathological changes markedly and Sirus red staining showed that TFA reduced collagen deposition, alleviated formation and extent of liver pseudolobule. Collagen I and α-SMA immunohistochemical staining showed that staining area and extent markedly decreased in TFA groups compared with the model group. TFA could increase PPARγ, it regulated target UCP2, and FXR levels significantly compared with the model group (in the low-TFA group all P<0.05, in the high group all P<0.01).

CONCLUSIONTFA could improve liver function, alleviate liver pathological changes, and reduce collagen deposition and formation of liver pseudolobule in rats with liver cirrhosis. The antifibrotic effect of TFA was through regulating PPARγ signal pathway and the interaction with FXR.

Actins ; metabolism ; Animals ; Blotting, Western ; Body Weight ; drug effects ; Collagen Type I ; metabolism ; Dimethylnitrosamine ; Drugs, Chinese Herbal ; pharmacology ; therapeutic use ; Flavonoids ; pharmacology ; therapeutic use ; Hydroxyproline ; metabolism ; Liver ; drug effects ; pathology ; Liver Cirrhosis ; blood ; drug therapy ; genetics ; pathology ; Male ; Organ Size ; drug effects ; PPAR gamma ; genetics ; metabolism ; Plant Extracts ; pharmacology ; therapeutic use ; RNA, Messenger ; genetics ; metabolism ; Rats, Sprague-Dawley ; Real-Time Polymerase Chain Reaction ; Receptors, Cytoplasmic and Nuclear ; genetics ; metabolism ; Uncoupling Protein 2 ; genetics ; metabolism

Vertical sleeve gastrectomy (VSG) is becoming more and more popular among the world. Despite its dramatic efficacy, however, the mechanism of VSG remains largely undetermined. This study aimed to test interferon (IFN)-γ secretion n of mesenteric lymph nodes in obese mice (ob/ob mice), a model of VSG, and its relationship with farnesoid X receptor (FXR) expression in the liver and small intestine, and to investigate the weight loss mechanism of VSG. The wild type (WT) mice and ob/ob mice were divided into four groups: A (WT+Sham), B (WT+VSG), C (ob/ob+Sham), and D (ob/ob+VSG). Body weight values were monitored. The IFN-γ expression in mesenteric lymph nodes of ob/ob mice pre- and post-operation was detected by flow cytometry (FCM). The FXR expression in the liver and small intestine was detected by Western blotting. The mouse AML-12 liver cells were stimulated with IFN-γ at different concentrations in vitro. The changes of FXR expression were also examined. The results showed that the body weight of ob/ob mice was significantly declined from (40.6±2.7) g to (27.5±3.8) g on the 30th day after VSG (P<0.05). At the same time, VSG induced a higher level secretion of IFN-γ in mesenteric lymph nodes of ob/ob mice than that pre-operation (P<0.05). The FXR expression levels in the liver and small intestine after VSG were respectively 0.97±0.07 and 0.84±0.07 fold of GAPDH, which were significantly higher than pre-operative levels of 0.50±0.06 and 0.48±0.06 respectively (P<0.05). After the stimulation of AML-12 liver cells in vitro by different concentrations of IFN-γ (0, 10, 25, 50, 100, and 200 ng/mL), the relative FXR expression levels were 0.22±0.04, 0.31±0.04, 0.39±0.05, 0.38±0.05, 0.56±0.06, and 0.35±0.05, respectively, suggesting IFN-γ could distinctly promote the FXR expression in a dose-dependent manner in comparison to those cells without IFN-γ stimulation (P<0.05). It was concluded that VSG induces a weight loss in ob/ob mice by increasing IFN-γ secretion of mesenteric lymph nodes, which then increases the FXR expression of the liver and small intestine.
Animals ; Body Weight ; Cell Line ; Gastrectomy ; methods ; Gene Expression ; Hepatocytes ; cytology ; drug effects ; metabolism ; Interferon-gamma ; biosynthesis ; pharmacology ; secretion ; Intestine, Small ; drug effects ; metabolism ; Liver ; drug effects ; metabolism ; Lymph Nodes ; drug effects ; metabolism ; Mesentery ; drug effects ; metabolism ; Mice ; Mice, Obese ; Obesity ; metabolism ; pathology ; surgery ; Receptors, Cytoplasmic and Nuclear ; agonists ; genetics ; metabolism ; Weight Loss

To observe the effect of calycosin on the proliferation and activation of primary hepatic stellate cells (HSCs) in rats, and prove calycosin shows the effects through peroxisome proliferator-activated receptor γ(PPARγ) and farnesoid X receptor (FXR). The results indicated that calycosin could inhibit HSC proliferation and expressions of activation marker smooth muscle actin-α and type I collagen. With the increase in HSC activation time, FXR expression reduced, but with no notable impact from calycosin. Calycosin could up-regulate PPARγ expression and its nuclear transition in a concentration-dependent manner. Its prohibitory effect on HSC activation could be blocked by PPARγ antagonist. In conclusion, calycosin could inhibit HSC activation and proliferation, which may be related with the up-regulation of PPARγ signal pathway.
Animals ; Cell Proliferation ; drug effects ; Cells, Cultured ; Drugs, Chinese Herbal ; pharmacology ; Hepatic Stellate Cells ; cytology ; drug effects ; metabolism ; Isoflavones ; pharmacology ; Male ; PPAR gamma ; genetics ; metabolism ; Rats ; Rats, Sprague-Dawley ; Receptors, Cytoplasmic and Nuclear ; genetics ; metabolism ; Up-Regulation ; drug effects

OBJECTIVETo investigate the expression of farnesoid X receptor (FXR) and the effect of emodin on FXR expression in a rat model of acute cholestatic hepatitis.

METHODSNinety adult Sprague-Dawley rats were randomly divided into normal control, model, and emodin groups (n=30 each). The model and emodin groups were given alpha-naphthylisothiocyanate (ANIT) 50 mg/kg by gavage to establish an animal model of cholestatic hepatitis, while the normal control group was given an equal volume of sesame oil. The emodin group was given emodin by gavage every day from 4 days before the model was prepared until the time of sacrifice, while the model and normal control groups were given an equal volume of sodium carboxymethyl cellulose solution. At 24, 48 and 72 hours after the model was prepared, serum level of total bilirubin (TB), direct bilirubin (DB), alanine aminotransferase (ALT), and total bile acids (TBA) were measured by Aeroset automatic biochemical analyzer, and the mRNA expression of FXR in the liver tissue was measured by real-time PCR.

RESULTSAt all time points FXR mRNA expression in the model group decreased, but serum levels of TB, DB, ALT and TBA increased significantly compared with the normal control group (P<0.05). The emodin group had significantly higher mRNA expression of FXR and significantly lower serum levels of TB, DB, ALT, and TBA compared with the model group (P<0.05).

CONCLUSIONSEmodin can significantly reduce serum levels of TB, DB, ALT, and TBA in rats with ANIT-induced cholestatic hepatitis, probably by promoting FXR expression.

Acute Disease ; Alanine Transaminase ; blood ; Animals ; Cholestasis, Intrahepatic ; drug therapy ; metabolism ; Disease Models, Animal ; Emodin ; pharmacology ; therapeutic use ; Hepatitis ; drug therapy ; metabolism ; Liver ; pathology ; Male ; RNA, Messenger ; analysis ; Rats ; Rats, Sprague-Dawley ; Receptors, Cytoplasmic and Nuclear ; genetics

The constitutive androstane receptor (CAR, NR1I3) plays a crucial role in the regulation of drug metabolism, energy homeostasis, and cancer development through modulating the transcription of its numerous target genes. Different from prototypical nuclear receptors, CAR can be activated by either direct ligand binding or ligand-independent (indirect) mechanisms both initiated with nuclear translocation of CAR from the cytoplasm. In comparison to the well-defined ligand-based activation, indirect activation of CAR appears to be exclusively involved in the nuclear translocation through mechanisms yet to be fully understood. Accumulating evidence reveals that without activation, CAR forms a protein complex in the cytoplasm where it can be functionally affected by multiple signaling pathways. In this review, we discuss recent progresses in our understanding of the signaling regulation of CAR nuclear accumulation and activation. We expect that this review will also provide greater insight into the similarity and difference between the mechanisms of direct vs. indirect human CAR activation.
Active Transport, Cell Nucleus ; genetics ; Cytoplasm ; metabolism ; Hepatocytes ; metabolism ; Humans ; Ligands ; Protein Transport ; genetics ; Receptors, Cytoplasmic and Nuclear ; genetics ; metabolism ; Signal Transduction ; genetics

OBJECTIVETo analyze the effects of ursodeoxycholic acid (UDCA) on the mRNA expression of multidrug resistance protein 3 (MDR3) and farnesoid X receptor (FXR) in infants with cholestatic hepatitis.

METHODSTwenty-eight infants who were diagnosed with cholestatic hepatitis between July 2008 and July 2010 were included in the study. These patients received treatment with UDCA. The mRNA expression levels of MDR3 and FXR were measured by real-time quantitative RT-PCR with SYBR Green I, before and after treatment with UDCA.

RESULTSAfter treatment with UDCA, the infants with cholestatic hepatitis had significantly decreased serum levels of total bilirubin, direct bilirubin, alanine aminotransferase, and gamma-glutamyltransferase (P<0.05) and significantly increased mRNA expression of MDR3 (P<0.05). No significant change in mRNA expression of FXR was observed, however (P>0.05).

CONCLUSIONSUDCA improves liver function indices in infants with cholestatic hepatitis, which may be related to up-regulated mRNA expression of MDR3.

ATP Binding Cassette Transporter, Sub-Family B ; genetics ; Cholestasis ; complications ; drug therapy ; metabolism ; Female ; Gene Expression Regulation ; Hepatitis ; drug therapy ; etiology ; metabolism ; Humans ; Infant ; Male ; RNA, Messenger ; analysis ; Receptors, Cytoplasmic and Nuclear ; genetics ; Ursodeoxycholic Acid ; pharmacology ; therapeutic use

This paper is to report the development of a high-throughput in vitro system to screen hPXR/CAR mediated CYP2B6 drug inducers, and the application of it into the quick determination of induction activity toward CYP2B6 by various commonly used traditional Chinese medicines (TCMs) extract. Dual reporter gene assays were performed. The hPXR/CAR expression vectors and the reporter vector pGL3-CYP2B6-Luc involved in the distal and proximal promoters of CYP2B6 were co-transfected into HepG2 cells. Relative luciferase activities in cell lysate were analyzed after 48 h treatment of blank vehicle or drugs to determine the induction activity toward CYP2B6 by various commonly used TCMs extract. The positive hPXR/hCAR activators rifampicin and CITCO were applied to make sure that the reporter gene model was successfully established. Then 5 kinds of commonly used TCM extracts and 1 herbal compound were successfully investigated, some were found to activate hPXR or hCAR and therefore have the potential to induce CYP2B6 enzyme. This is the first domestic article to report the hCAR3-mediated CYP2B6 induction model and the establishment of a reporter gene system for hPXR/CAR-mediated CYP2B6 induction can be an effective and systemic in vitro method to investigate the drug inducers of CYP2B6 and to explain the mechanism involved.
Aryl Hydrocarbon Hydroxylases ; genetics ; metabolism ; Cytochrome P-450 CYP2B6 ; Drugs, Chinese Herbal ; isolation & purification ; pharmacology ; Genes, Reporter ; Genetic Vectors ; Hep G2 Cells ; High-Throughput Screening Assays ; Humans ; Luciferases ; genetics ; metabolism ; Oximes ; pharmacology ; Plants, Medicinal ; chemistry ; Plasmids ; Receptors, Cytoplasmic and Nuclear ; genetics ; metabolism ; Receptors, Steroid ; genetics ; metabolism ; Rifampin ; pharmacology ; Thiazoles ; pharmacology ; Transfection

This study is purposed to investigate the effects of praeruptorin A (PA) and praeruptorin C (PC) on UGT1A1 in HepG2 cells through hCAR pathway. PA and PC were incubated with HepG2 cells for 24 h and 48 h, mRNA and protein expressions of UGT1A1 were determined by real-time PCR and Western blotting assays. Additionally, effects of PA and PC on UGT1A1 mRNA and protein expressions were also measured after transient transfection of a specific CAR siRNA for 72 h in HepG2 cells. UGT1A1 mRNA and protein expression levels were significantly increased by PA and PC after incubation for 48 h. Moreover, the mRNA and protein up-regulations of UGT1A1 were attenuated by transient transfection of a specific CAR siRNA, suggesting the induction was mediated by CAR. The results suggest that PA and PC can significantly up-regulate UGT1A1 expression partially via the CAR-mediated pathway.
Apiaceae ; chemistry ; Coumarins ; isolation & purification ; pharmacology ; Drugs, Chinese Herbal ; pharmacology ; Glucuronosyltransferase ; genetics ; metabolism ; Hep G2 Cells ; Humans ; Plant Roots ; chemistry ; Plants, Medicinal ; chemistry ; RNA, Messenger ; metabolism ; RNA, Small Interfering ; genetics ; metabolism ; Receptors, Cytoplasmic and Nuclear ; genetics ; metabolism ; Signal Transduction ; Transfection