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

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

Farnesoid X receptor (FXR) belongs to the nuclear receptor superfamily. It is highly related to the formation of metabolic syndrome and the glucose homeostasis, and therefore represents an important drug target against metabolic diseases and diabetes. In recent years, great progress has been made in the agonists, antagonists, and crystal structures of FXR. The diverse FXR ligands and their structure-activity relationship are reviewed in this article. The advances in the crystal structures of FXR in complex with different ligands are also introduced.
Animals ; Anticholesteremic Agents ; chemical synthesis ; chemistry ; pharmacology ; Azepines ; chemical synthesis ; chemistry ; pharmacology ; Benzene Derivatives ; chemical synthesis ; chemistry ; pharmacology ; Chenodeoxycholic Acid ; analogs & derivatives ; chemical synthesis ; chemistry ; pharmacology ; Crystallization ; Humans ; Indoles ; chemical synthesis ; chemistry ; pharmacology ; Isoxazoles ; chemical synthesis ; chemistry ; pharmacology ; Ligands ; Molecular Structure ; Multienzyme Complexes ; chemical synthesis ; chemistry ; pharmacology ; Pregnenediones ; chemical synthesis ; chemistry ; pharmacology ; Receptors, Cytoplasmic and Nuclear ; agonists ; antagonists & inhibitors ; metabolism ; Structure-Activity Relationship

OATP1B3, a member of SLC superfamily, is specifically expressed on the sinusoidal membrane of hepatocytes and is considered to be important in hepatic drug elimination. The overexpression of OATP1B3 was found recently in tumor tissues such as prostate, colon, and pancreatic tumors. Sequence variations in SLCO1B3 gene, such as SNPs, have been described and a common haplotype consisting of 334T>G and 699G>A SNPs is related to altered transport characteristics of OATP1B3. OATP1B3 is of relevance to drug metabolism through affecting alteration of hepatic concentration of endo- and xenobiotic compounds that interact with nuclear receptors such as PXR and CAR, and thereby directly alter the extent of target gene transcription, including major CYP isoenzymes such as CYP3A4. This review will provide an overview of substrates and inhibitors of OATP1B3 and subsequently to assess the effect of genetic mutation on transport activity. The studies linking OATP1B3 with cancer clinical outcomes are also discussed in this review.
Animals ; Biological Transport ; Cytochrome P-450 CYP3A ; metabolism ; Drug Interactions ; Gene Expression Regulation, Neoplastic ; Gene Frequency ; Hepatocytes ; metabolism ; Humans ; Liver ; metabolism ; Neoplasms ; metabolism ; Organic Anion Transporters, Sodium-Independent ; antagonists & inhibitors ; chemistry ; genetics ; Polymorphism, Single Nucleotide ; RNA, Messenger ; metabolism ; Receptors, Cytoplasmic and Nuclear ; metabolism ; Receptors, Steroid ; metabolism ; Solute Carrier Organic Anion Transporter Family Member 1B3

Animals ; Apoptosis ; Cell Cycle ; Cell Cycle Proteins ; genetics ; metabolism ; physiology ; DNA Repair ; Homeodomain Proteins ; genetics ; metabolism ; physiology ; Humans ; Inhibitor of Growth Protein 1 ; Intracellular Signaling Peptides and Proteins ; genetics ; metabolism ; physiology ; Neoplasm Metastasis ; Neoplasms ; metabolism ; pathology ; Neovascularization, Pathologic ; pathology ; Nuclear Proteins ; genetics ; metabolism ; physiology ; Prognosis ; Receptors, Cytoplasmic and Nuclear ; genetics ; metabolism ; physiology ; Signal Transduction ; Transcription Factors ; genetics ; metabolism ; physiology ; Tumor Suppressor Protein p53 ; metabolism ; Tumor Suppressor Proteins ; chemistry ; genetics ; metabolism ; physiology

OBJECTIVETo identify and elucidate the vasorelaxant activity of homoisoflavonoids, the main chemical components from Lignum Sappan (the stems of Caesalpinia sappan), in isolated rat thoracic aortic rings pre-contracted with phenylephrine (PE, 1 micromol x L(-1)) and KCl (60 mmol x L(-1)).

METHODThe tension of rat thoracic aorta rings was used to evaluated the vasorelaxant activities of four homoisoflavonoids, brazlin (1), (E)-3-(3,4-dihydroxybenzylidene)-7-hydroxychroman-4-one (2), sappanone B (3), 3-deoxysappanone B (4).

RESULTCumulative addition of homoisoflavonoids (2, 3 and 4) (50-1000 micromol x L(-1)) exhibited an acute relaxation either in endothelium-intact or endothelium-denuded rings in a concentration-dependent manner. However, this relaxation was significantly inhibited in endothelium-denuded condition and in the presence of endothelial nitric oxide synthase (eNOS) inhibitor, N(W)-nitro-L-arginine methyl ester (L-NNA, 100 micromol x L(-1)), and a soluble guanylate cylcase (sGC) inhibitor, methylene blue (MB, 10 micromol x L(-1)) when addition of variation homoisoflavonoids brazlin (1) (50-1000 micromol x L(-1)).

CONCLUSIONThese results indicate that normo-homoisoflavonoids (2, 3 and 4) from Caesalpinia sappan mediates endothelium-independent vasodilator action in rat thoracic aortic rings, while the variation homoisoflavonoids brazlin elicits endothelium-dependent relaxation might via nitric oxide (NO)-cGMP pathway. This research could explain the pharmacological activities of homoisoflavonoids to a certain degree.

Animals ; Aorta, Thoracic ; drug effects ; physiology ; Caesalpinia ; chemistry ; Endothelium ; metabolism ; Enzyme Inhibitors ; pharmacology ; Flavonoids ; chemistry ; pharmacology ; Guanylate Cyclase ; antagonists & inhibitors ; Male ; Muscle Contraction ; drug effects ; NG-Nitroarginine Methyl Ester ; pharmacology ; Nitric Oxide Synthase Type III ; antagonists & inhibitors ; Phenylephrine ; pharmacology ; Potassium Chloride ; pharmacology ; Rats ; Receptors, Cytoplasmic and Nuclear ; antagonists & inhibitors ; Soluble Guanylyl Cyclase ; Vasodilation ; drug effects ; Vasodilator Agents ; chemistry ; pharmacology

Use of adenoviruses as vehicle for gene therapy requires that target cells express appropriate receptors such as coxsakievirus and adenovirus receptor (CAR). We show here that CAR-deficiency in cancer cells, that limits adenoviral gene delivery, can be overcome by using adenovirus complexed with the liposome, Ad-PEGPE [1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(poly-ethylene glycol)-2000]. We first confirmed that CT-26 mouse colon cancer cells are deficient in CAR by RT-PCR, and then showed that CT-26 cells infected with Ad-GFP/PEGPE exhibited highly enhanced expression of green fluorescent protein (GFP), compared with those infected with Ad-GFP. GFP expression depends on the dose of liposome and adenovirus. Luciferase expression in livers treated with Ad-luc/PEGPE was about 1,000-fold less than those infected with Ad-luc. In a liver metastasis mouse tumor model developed by intrasplenic injection of CT-26 cells, luciferase expression following i.v. injection of Ad-luc/PEGPE was significantly higher in tumors than in adjacent non-neoplastic liver. Following systemic administration of Ad-GFP/PEGPE, GFP expression increased in tumors more than in adjacent liver while the reverse was true following administration of Ad-GFP. In the latter case, GFP expression was higher in liver than in tumors. This study demonstrates that systemic delivery of PEGPE-adenovirus complex is an effective tool of adenoviral delivery as it overcomes limitation due to CAR deficiency of target cells while reducing hepatic uptake and enhancing adenoviral gene expression in tumors.
*Adenoviridae/genetics/metabolism ; Animals ; Colonic Neoplasms/*genetics/metabolism/pathology/*therapy ; Dose-Response Relationship, Drug ; Gene Therapy ; *Gene Transfer Techniques ; Genetic Vectors ; Green Fluorescent Proteins/genetics ; Liposomes/administration & dosage/chemistry/pharmacokinetics/*therapeutic use ; Liver/drug effects/metabolism ; Male ; Mice ; Mice, Inbred BALB C ; Mice, Transgenic ; NIH 3T3 Cells ; Phosphatidylethanolamines/administration & dosage ; Polyethylene Glycols/administration & dosage ; Receptors, Cytoplasmic and Nuclear/deficiency/genetics ; Receptors, Virus/deficiency/*genetics ; Transcription Factors/deficiency/genetics ; Tumor Cells, Cultured

In this study, we investigated the role of Nur77, an orphan nuclear receptor, in HIF-alpha transcriptional activity. We found that Nur77 associates and stabilizes HIF-1alpha via indirect interaction. Nur77 was found to interact with pVHL in vivo via the alpha-domain of pVHL. By binding to pVHL, Nur77 competed with elongin C for pVHL binding. Moreover, Nur77-binding to pVHL inhibited the pVHL-mediated ubiquitination of HIF-1alpha and ultimately increased the stability and transcriptional activity of HIF-1alpha. The ligand-binding domain of Nur77 was found to interact with pVHL and the expression of this ligand-binding domain was sufficient to stabilize and transactivate HIF-1alpha. Under the conditions that cobalt chloride was treated or pVHL was knocked down, Nur77 could not stabilize HIF-alpha. Moreover, Nur77 could not further stabilize HIF-2alpha in A498/VHL stable cells, which is consistent with our finding that Nur77 indirectly stabilizes HIF-alpha by binding to pVHL. Thus, our results suggest that an orphan nuclear receptor Nur77 binds to pVHL, thereby stabilizes and increases HIF-alpha transcriptional activity under the non- hypoxic conditions.
Animals ; DNA-Binding Proteins/chemistry/*metabolism ; Humans ; Hypoxia-Inducible Factor 1, alpha Subunit/*genetics ; Models, Biological ; PC12 Cells ; Protein Binding ; *Protein Processing, Post-Translational ; Protein Structure, Tertiary ; Rats ; Receptors, Cytoplasmic and Nuclear/chemistry/*metabolism ; Receptors, Steroid/chemistry/*metabolism ; Thermodynamics ; Transcription Factors/chemistry/*metabolism ; Transcriptional Activation/genetics ; Ubiquitination ; Up-Regulation/*genetics ; Von Hippel-Lindau Tumor Suppressor Protein/*antagonists & inhibitors/chemistry/*metabolism

HIV-1 Rev is an indispensable regulatory factor of the virion protein expression. The interaction between Rev and RRE RNA accelerates the nuclear export of viral mRNA. The unspliced and singly spliced mRNA will be degraded in the absence of Rev, resulting in the interception of HIV-1 replication at the same time. The pivotal role that Rev plays in HIV-1 replication as a trans-acting factor makes it a new target in the research of AIDS drugs. In this review, the function of Rev, Rev-RRE interaction, as well as their related inhibitors are reported.
Active Transport, Cell Nucleus ; Amino Acid Sequence ; Anti-HIV Agents ; chemistry ; pharmacology ; Cell Nucleus ; metabolism ; Fatty Acids, Unsaturated ; chemistry ; pharmacology ; Framycetin ; chemistry ; pharmacology ; HIV-1 ; genetics ; metabolism ; physiology ; Karyopherins ; metabolism ; RNA, Messenger ; genetics ; RNA, Viral ; genetics ; Receptors, Cytoplasmic and Nuclear ; metabolism ; Transcription, Genetic ; Virus Replication ; rev Gene Products, Human Immunodeficiency Virus ; antagonists & inhibitors ; metabolism