OBJECTIVETo investigate the effect of FXR on scavenger receptor class B type I (SR-BI) expression.

METHODSHuman vascular endothelium Eahy926 cells were treated with FXR agonist androsterone, and the specific target gene of FXR SHP mRNA was detected by RT-PCR. SR-BI mRNA and protein were determined using RT-PCR, real-time PCR and Western blotting.

RESULTSThe level of SHP mRNA in Eahy926 cells increased after androsterone treatment at different concentrations for 24 h, demonstrating FXR activation in the cells. RT-PCR, real-time PCR and Western blotting detected increased SR-BI expression at both mRNA and protein levels after FXR activation.

CONCLUSIONFXR increases the expression of SR-BI in human vascular endothelium cells.

Androsterone ; pharmacology ; Cell Line ; Endothelial Cells ; drug effects ; metabolism ; Humans ; Receptors, Cytoplasmic and Nuclear ; agonists ; metabolism ; Scavenger Receptors, Class B ; metabolism

Hyperlipidemia is one of the most important risk factors for atherosclerosis, coronary heart disease and other cardiovascular diseases. It is the main effect of lipid-lowering drugs to reduce the plasma low-density lipoprotein or to enhance high-density lipoprotein. Niemann-Pick C1 like 1 protein (NPC1L1), acyl-coenzyme A: cholesterol acyltransferases (ACAT), ATP binding cassette transporter G member 5 and member 8 (ABCG5/G8), microsomal triglyceride transfer protein (MTP), monoacylglycerol acyltransferase, diacylglycerol acyltransferases (MAGT), peroxisome proliferator-activated receptor (PPAR), farnesoid X receptor (FXR), and proprotein convertase subtilisin/kexin type 9 (PCSK9) play key roles in the metabolism of lipid, which are regarded as the targets of anti-hyperlipidemia drugs and evidence for clinic choice of lipid-lowering drugs. These proteins are considered as breakthrough points for new lipid-lowering drug development.
Binding Sites ; Humans ; Hyperlipidemias ; drug therapy ; Hypolipidemic Agents ; pharmacology ; therapeutic use ; Lipid Metabolism ; drug effects ; Receptors, Cytoplasmic and Nuclear ; drug effects

OBJECTIVETo investigate the effects of GW4064, a farnesoid X receptor (FXR) agonist, on adiponectin and its receptors during the differentiation of 3T3-L1 preadipocytes and on adiponectin receptors in HepG2 cells.

METHODSThe mRNA expressions of FXR, PPARγ2, adiponectin, AdipoR1, and AdipoR2 and the protein levels of adiponectin on days 0, 2, 4, 6, and 8 during the differentiation of 3T3-L1 preadipocytes treated with GW4064 were detected by fluorescent real-time PCR and ELISA, respectively. The mRNA expressions of AdipoR1 and AdipoR2 in HepG2 cells were also examined at 0, 12, 24, and 48 h after GW4064 treatment.

RESULTSThe mRNA expressions of FXR, PPARγ2, adiponectin, and AdipoR2 in 3T3-L1 preadipocytes and AdipoR2 in HepG2 cells treated with GW4064 was significantly increased compared with the control group (all P<0.05). The protein level of adiponectin was also significantly increased after GW4064 treatment. The expression of AdipoR1 in either 3T3-L1 preadipocytes or HepG2 cells showed no significant changes after GW4064 treatment.

CONCLUSIONGW4064 can up-regulate the expressions of FXR, PPARγ2, adiponectin, AdipoR2 in 3T3-L1 preadipocytes and AdipoR2 in HepG2 cells. As adiponectin and its receptors are two important factors in the treatment of non-alcoholic fatty liver disease, FXR agonist may potentially produce therapeutic effect on non-alcoholic fatty liver disease and can regulate adipocytes via up-regulating PPARγ during adipocyte differentiation.

3T3-L1 Cells ; Adiponectin ; metabolism ; Animals ; Cell Differentiation ; drug effects ; Hep G2 Cells ; Humans ; Isoxazoles ; pharmacology ; Mice ; PPAR gamma ; metabolism ; Receptors, Adiponectin ; metabolism ; Receptors, Cytoplasmic and Nuclear ; agonists

Zebrafish is widely used as a model organism in the process of drug discovery. It expresses drug metabolizing enzymes like cytochrome P450 (CYP450), uridine 5'-diphospho-glucuronosyltransferase (UGT) and nuclear receptors like pregnane X receptor (PXR), aryl hydrocarbon receptor (AHR), etc. This article summarized the profiles of main drug metabolizing enzymes and nuclear receptors, and reviewed the advances on xenobiotics metabolism in zebrafish.
Animals ; Cytochrome P-450 Enzyme System ; metabolism ; Embryo, Nonmammalian ; drug effects ; Glucuronosyltransferase ; metabolism ; Inactivation, Metabolic ; Pharmaceutical Preparations ; metabolism ; Polychlorinated Dibenzodioxins ; toxicity ; Receptors, Aryl Hydrocarbon ; metabolism ; Receptors, Cytoplasmic and Nuclear ; metabolism ; Receptors, Steroid ; metabolism ; Teratogens ; toxicity ; Xenobiotics ; metabolism ; Zebrafish ; embryology ; metabolism

Carboxylesterases (CESs) play important roles in the metabolism of endogenous and foreign compounds in physiological and pharmacological responses. The aim of this study was to investigate the effect of dexamethasone at different doses on the expression of CES1 and CES2. Imidapril and irinotecan hydrochloride (CPT-11) were used as special substrates for CES1 and CES2, respectively. Rat hepatocytes were cultured and treated with different concentrations of dexamethasone. The hydrolytic activity of CES1 and CES2 was tested by incubation experiment and their expression was quantitated by real-time PCR. A pharmacokinetic study was conducted in SD rats to further evaluate the effect of dexamethasone on CESs activity in vivo. Western blotting was performed to investigate the regulatory mechanism related to pregnane X receptor (PXR) and glucocorticoid receptor (GR). The results showed that exposure of cultured rat hepatocytes to nanomolar dexamethasone inhibited the imidapril hydrolase activity, which was slightly elevated by micromolar dexamethasone. For CES2, CPT-11 hydrolase activity was induced only when dexamethasone reached micromolar levels. The real-time PCR demonstrated that CES1 mRNA was markedly decreased by nanomolar dexamethasone and increased by micromolar dexamethasone, whereas CES2 mRNA was significantly increased by micromolar dexamethasone. The results of a complementary animal study showed that the concurrent administration of dexamethasone significantly increased the plasma concentration of the metabolite of imidapril while the ratio of CPT-11 to its metabolite SN-38 was significantly decreased. PXR protein was gradually increased by serial concentrations of dexamethasone. However, only nanomolar dexamethasone elevated the level of GR protein. The different concentrations of dexamethasone required suggested that suppression of CES1 may be mediated by GR whereas the induction of CES2 may result from the role of PXR. It was concluded that dexamethasone at different concentrations can differentially regulate CES1 and CES2.
Animals ; Carboxylic Ester Hydrolases ; genetics ; Dexamethasone ; pharmacology ; Gene Expression ; drug effects ; immunology ; Male ; Rats ; Rats, Sprague-Dawley ; Receptors, Cytoplasmic and Nuclear ; metabolism

Polyunstaurated fatty acids (PUFAs) not only are essential component of cells in maintaining function and composing organelle, but also control gene transcription of enzymes which are involved in differentiation, growth and metabolism in organisms. Resent studies have been shown that PUFA interact directly with nuclear receptors such as PPARs, LXR, HNF-4, other mechanism are indirect and rest with transcription factors such as SREBP. PUFA affect cell function through diverse pathways. The roles of such factors and PUFA in mediating the nuclear effects are addressed in order to elucidate the mechanism of PUFA in regulating gene expression. Further understanding of gene mechanism of regulation at the level of molecule would prompt the development of nutrition, health and medical treatment.
DNA-Binding Proteins ; metabolism ; Fatty Acids, Omega-3 ; pharmacology ; Gene Expression Regulation ; drug effects ; Hepatocyte Nuclear Factor 1 ; metabolism ; Humans ; Liver X Receptors ; Orphan Nuclear Receptors ; Peroxisome Proliferator-Activated Receptors ; metabolism ; Receptors, Cytoplasmic and Nuclear ; metabolism ; Sterol Regulatory Element Binding Protein 1 ; metabolism ; Transcription, Genetic ; drug effects

OBJECTIVETo investigate the effects of LPS and/or TNF-alpha on periodontal ligament cell (PDLC) proliferation and OPG secretion.

METHODSHealthy premolars extracted for orthodontic reasons from a 12 years old boy were obtained, and periodontal tissues were collected and cultured to obtain PDLCs. Cloned PDLCs were obtained by means of limited dilutions, and were characterized as follows: alkaline phosphatase activity, collagen III production and bone-like nodules formation. LPS and rhTNF-alpha were added into culture media and their effects on PDLC proliferation and OPG secretion were observed. The OPG concentrations in cell culture supernatants were detected by sandwich ELISA. Living cell numbers were demonstrated by MTT test. The average levels of OPG secretion by a single cell were calculated by dividing OPG concentration with MTT result.

RESULTSrhTNF-alpha above 10 micro g/L decreased the mtt and opg detecting results, but increased the opg/mtt values (P < 0.05). However, LPS had no effect on mtt, opg or opg/mtt values. Neither it had any interaction with rhTNF-alpha (P > 0.05).

CONCLUSIONSTNF-alpha prohibits the proliferation of PDLCs but enhances their OPG secretion. However, LPS has no effect on neither side. Our works support the hypothesis that there may be an inverse feedback regulation pattern of increasing periodontal OPG production against local bone resorption activity. PDLCs might not be the natural target cells of LPS' direct cytotoxic effect.

Child ; Glycoproteins ; biosynthesis ; drug effects ; Humans ; In Vitro Techniques ; Lipopolysaccharides ; pharmacology ; Male ; Osteoprotegerin ; Periodontal Ligament ; metabolism ; pathology ; Receptors, Cytoplasmic and Nuclear ; biosynthesis ; drug effects ; Receptors, Tumor Necrosis Factor ; biosynthesis ; drug effects ; Tumor Necrosis Factor-alpha ; pharmacology

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

BACKGROUNDStatin therapy has affected glucose homoeostasis of type 2 diabetes patients, which could be related with bile acids metabolism. Whether bile acid metabolism and the expression of farnesoid X receptor (FXR), liver X receptor-α (LXR-α) and sterol regulatory element-binding protein (Srebp)-1c is regulated by hyperglycemia, or whether simvastatin therapy led to higher glucose is related with down-regulated expression of FXR in diabetic rats remained unclear.

METHODSForty male Wistar rats were randomly divided into four groups: normal control rats, insulin resistance rats, diabetic model rats, and the late simvastatin induced diabetic rats. Normal control rats were fed with standard diet, others were fed with high-fat diet. Diabetic model rats were induced by a single intraperitoneal injection of streptozotocin (STZ). The late simvastatin induced diabetic rats started simvastatin administration after STZ induced diabetic model rats. Characteristics of fasting blood glucose (FPG), lipid files and total bile acids (TBAs) were measured and the oral glucose tolerance test (OGTT) was performed after overnight fasting at the eighth weekend. RNA and protein levels of FXR, LXR-α and Srebp-1c were tested by Western blotting and reverse transcription polymerase chain reaction (RT-PCR).

RESULTSThe insulin resistance rats showed higher glucose, lipid files and lower expression of FXR compared with normal control rats (P > 0.05). The diabetic model rats showed significantly higher glucose, lipid files, TBA and lower expression of FXR compared with insulin resistance rats (P < 0.05). The late simvastatin induced diabetic rats displayed higher glucose and TBA and lower expression of FXR compared with diabetic model rats (P < 0.05).

CONCLUSIONSChanges in bile acid homeostasis, including the alterations of bile acid levels and bile acid receptors, are either a cause or a consequence of the metabolic disturbances observed during diabetic models. Statin therapy induced hyperglycemia may be related with FXR, SHP, LXR-α and Srebp-1 pathways.

Animals ; Blood Glucose ; drug effects ; metabolism ; Diabetes Mellitus, Experimental ; drug therapy ; metabolism ; Glucose Tolerance Test ; Homeostasis ; drug effects ; Insulin Resistance ; physiology ; Liver X Receptors ; Male ; Orphan Nuclear Receptors ; metabolism ; Rats ; Rats, Wistar ; Receptors, Cytoplasmic and Nuclear ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Simvastatin ; therapeutic use ; Sterol Regulatory Element Binding Protein 1 ; metabolism

OBJECTIVETo investigate the effect of niacin on HDL-induced cholesterol efflux and LXRalpha expression in adipocytes from hypercholesterolemic rabbits.

METHODSTwelve rabbits fed with high-cholesterol diet for 8 weeks were randomly divided into two groups: (1) high cholesterol group (n = 6): maintained high cholesterol diet for 6 weeks; (2) niacin group (n = 6): the same cholesterol diet plus niacin (0.2 g . kg(-1). d(-1)) for 6 weeks. Control group (n = 6) was fed with normal diet for 14 weeks. Subcutaneous adipose was collected for adipocyte culture. RT-PCR was used to evaluate adipocytes LXRalpha mRNA expressions. Cholesterol efflux rate was determined through measuring release of radioactivity from 3H-cholesterol prelabeled cells into medium containing HDL. The direct effect of niacin on LXRalpha and PPARgamma mRNA expression in primary rabbit adipocytes was assayed.

RESULTSHigh cholesterol diet resulted in decreased LXRalpha mRNA expressions and reduced cholesterol efflux rate in adipocytes. Six weeks of niacin treatment significantly enhanced the cholesterol efflux from adipocytes, which was related to the increased mRNA expressions of LXRalpha (r = 0.71, P < 0.05). In vitro study, niacin dose-dependently stimulated LXRalpha and PPARgamma mRNA expression in cultured adipocytes and there were positive correlations between various doses of niacin-induced cholesterol efflux and LXRalpha and PPARgamma mRNA expression (r = 0.83 P < 0.01, r = 0.76 P < 0.05, respectively).

CONCLUSIONLXRalpha and PPARgamma might play an important role in cholesterol efflux from adipocytes. Niacin can up-regulate LXRalpha and PPARgamma mRNA expressions and promote the cholesterol efflux in adipocytes from hypercholesterolemic rabbits.

Adipocytes ; drug effects ; metabolism ; Animals ; Cholesterol ; metabolism ; DNA-Binding Proteins ; metabolism ; Disease Models, Animal ; Hypercholesterolemia ; drug therapy ; metabolism ; Hyperlipidemias ; drug therapy ; metabolism ; Liver X Receptors ; Male ; Niacin ; pharmacology ; therapeutic use ; Orphan Nuclear Receptors ; PPAR gamma ; metabolism ; Rabbits ; Receptors, Cytoplasmic and Nuclear ; metabolism