Humans ; Protein Binding ; Receptors, Steroid ; agonists ; antagonists & inhibitors ; metabolism ; physiology

The development of chronic liver disease can be promoted by excessive fat accumulation, dysbiosis, viral infections and persistent inflammatory responses, which can lead to liver inflammation, fibrosis and carcinogenesis. An in-depth understanding of the etiology leading to chronic liver disease and the underlying mechanisms influencing its development can help identify potential therapeutic targets for targeted treatment. Orphan nuclear receptors (ONRs) are receptors that have no corresponding endogenous ligands to bind to them. The study of these ONRs and their biological properties has facilitated the development of synthetic ligands, which are important for investigating the effective targets for the treatment of a wide range of diseases. In recent years, it has been found that ONRs are essential for maintaining normal liver function and their dysfunction can affect a variety of liver diseases. ONRs can influence pathophysiological activities such as liver lipid metabolism, inflammatory response and cancer cell proliferation by regulating hormones/transcription factors and affecting the biological clock, oxidative stress, etc. This review focuses on the regulation of ONRs, mainly including retinoid related orphan nuclear receptors (RORs), pregnane X receptor (PXR), leukocyte cell derived chemotaxin 2 (LECT2), Nur77, and hepatocyte nuclear factor 4α (HNF4α), on the development of different types of chronic liver diseases in different ways, in order to provide useful references for the therapeutic strategies of chronic liver diseases based on the regulation of ONRs.
Humans ; Orphan Nuclear Receptors/metabolism* ; Receptors, Steroid/physiology* ; Ligands ; Liver ; Liver Diseases ; Intercellular Signaling Peptides and Proteins

Cholestatic liver diseases are characterized by impairments of bile flows and accumulations of biliary constituents such as bile acids and bilirubin. The changes of phase I and II metabolism and the hepatobiliary transport system minimize cholestatic liver injury. These adaptive responses are transcriptionally regulated by several nuclear receptors. Recent studies have revealed that the pregnane X receptor (PXR) and the constitutive androstane receptor (CAR) are key nuclear receptors for regulating many of the adaptive responses noted in cholestasis. PXR and CAR coordinately regulate not only bile acid metabolism and transport, but also bilirubin clearance. PXR and CAR ligands may be useful in the future for the treatment of cholestatic liver disease.
Transcription Factors/metabolism/*physiology ; Receptors, Steroid/metabolism/*physiology ; Receptors, Cytoplasmic and Nuclear/metabolism/*physiology ; Humans ; Cholestasis/metabolism/*physiopathology

OBJECTIVETo investigate whether pregnane X receptor (PXR) is involved in the induction of rat hepatic cytochrome P450 3A1/2 by zolmitriptan.

METHODSThe induction effects of zolmitriptan were investigated in three concentrations (100 micromol L(-1)), 50 micromolL(-1)) and 10 micromol L(-1))) using luciferase report gene method based on PXR. Pregnenolone-16 alpha-carbonitrile (PCN) was used as the positive control and the solvent DMSO as the negative control.

RESULTCompared with the negative groups, the positive and high level zolmitriptan groups exhibited a significant induction effect on CYP 3A1, the activity increased to 1.93 and 1.96 times, respectively (P<0.05). The positive, middle level and low level zolmitriptan groups exhibited a significant induction effect on CYP 3A2, the activity increase to 2.51, 2.10 and 1.63 times, respectively (P<0.01, <0.05 ).

CONCLUSIONZolmitriptan can significantly induce CYP 3A2 in low and middle concentrations and induce CYP 3A1 in high concentration.PXR is involved in the induction of CYP 3A1/2 by zolmitriptan.

Animals ; Cytochrome P-450 CYP3A ; drug effects ; metabolism ; Liver ; enzymology ; metabolism ; Oxazolidinones ; pharmacology ; Rats ; Receptors, Steroid ; metabolism ; physiology ; Tryptamines ; pharmacology

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

Pregnane X receptor (PXR) is key transcription factors which mainly regulate the expression of CYP3A genes. At the molecular level, PXR has been revealed the protection mechanism of the body against xenochemicals and a major mode of the drug-drug interactions. Besides playing an important role in drug metabolism and interactions, PXR and its target genes also play an important role in maintaining normal physiological function and homeostasis. Therefore, it is necessary to study the regulation of PXR and its related pharmacological effects of TCM and natural products, and to provide new clues for the new pharmacological pathway.
Animals ; Drug Evaluation, Preclinical ; Drugs, Chinese Herbal ; pharmacology ; Gene Expression ; drug effects ; Humans ; Receptors, Steroid ; antagonists & inhibitors ; genetics ; metabolism

OBJECTIVETo screen a group of traditional Chinese medicines with effect on pregnane X receptor (PXR)-mediated transcription regulation of P450 3A4 (CYP3A4); and to study whether they can induce the expression of CYP3A4 with a dose, time-dependent manner.

METHODTransient cotransfection reporter gene assays were performed with pCI-hPXR-neo, pGL3-CYP3A4-Luc and beta-galactosidase expression plasmid in HepG2 cells.

RESULTRhizoma Curcumae, Atractylodes lancea, A. macrocaphala and Poria cocos could induce transcriptional expression of CYP3A4. In the dose-effect study, 24 h after induction, 500 mg x L(-1) Rhizoma Curcumae, A. lancea, A. macrocaphala and Poria cocos, respectively, could induce the CYP3A4 gene expression with (6.82 +/- 0.09), (6.76 +/- 0.20), (5.49 +/- 0.13) and (4.97 +/- 0.07) folds, as compared with 0.1% DMSO treated cells. In the time-effect study, 500 mg x L(-1) Rhizoma curcumae, A. lancea, A. macrocaphala and Poria cocos for 48 h could induce the CYP3A4 gene expression with (7.74 +/- 0.54), (7.34 +/- 0.10), (5.54 +/- 0.11) and (5.32 +/- 0.18) folds, compared with 0.1% DMSO treated cells.

CONCLUSIONRhizoma Curcumae, A. lancea, A. macrocaphala and Poria cocos could induce the expression of CYP3A4 gene transcription through activating PXR.

Cell Line, Tumor ; Cytochrome P-450 CYP3A ; genetics ; Drugs, Chinese Herbal ; pharmacology ; Humans ; Receptors, Steroid ; metabolism ; Transcription, Genetic ; drug effects

Endocrine hormones are important factors in maintaining pregnancy as well as initiation of parturition. Progesterone is the major hormone maintaining myometrium quiescence, while glucocorticoids, prostaglandins and estrogen are among the major hormones involved in the initiation of parturition. Therefore progesterone withdrawal at the end of pregnancy is the prerequisite for the initiation of parturition. However, unlike most of the other species of mammals that the withdrawal of progesterone is achieved via reduction of progesterone synthesis or increased conversion of progesterone to estrogen, some mammals including the primates maintain high progesterone level throughout gestation and even during parturition. Accumulating lines of evidence indicate that the withdrawal of progesterone in human being is attained via the changes of the expression ratio of progesterone receptor subtypes and the changes of co-activators required for the activation of transcriptional activity of progesterone receptor. Here we reviewed the three major mechanisms, namely luteolysis, upregulation of placental P450c17 hydroxylase and changes of progesterone receptor functions, underlying progesterone withdrawal in late pregnancy in mammals.
Animals ; Female ; Humans ; Luteolysis ; physiology ; Parturition ; metabolism ; physiology ; Pregnancy ; Pregnancy Trimester, Third ; metabolism ; physiology ; Progesterone ; metabolism ; Receptors, Progesterone ; metabolism ; physiology ; Species Specificity ; Steroid 17-alpha-Hydroxylase ; metabolism

PXR, CAR and PPAR, widely distributed in the body, are important members of the nuclear receptors (NRs) family. The activities and gene expressions of drug-metabolizing enzymes (DMEs) and transporters can be regulated by the activation of NRs, which effect the drug disposition. Multidrug resistance (MDR) is the leading cause of failure in cancer therapy. NRs, including PXR, CAR and PPAR, were shown to regulate the expressions of DMEs and transporters involved in the drug metabolism and clearance, suggesting that the modulation of NRs can be considered as a new target to overcome MDR. This review described the research progress of NR family members PXR, CAR, PPAR and their transcriptional activation mechanism, the regulation of DMEs and transporters by NRs, which may provide a valuable reference for clinical medication and overcome of MDR.
Animals ; Cytochrome P-450 Enzyme System ; metabolism ; Drug Resistance, Multiple ; Drug Resistance, Neoplasm ; Humans ; Membrane Transport Proteins ; metabolism ; Neoplasms ; metabolism ; Peroxisome Proliferator-Activated Receptors ; metabolism ; Receptors, Cytoplasmic and Nuclear ; metabolism ; Receptors, Steroid ; metabolism

Nuclear receptors pregnane X receptor (PXR) and constitutive androstane receptor (CAR) are originally characterized as transcription factors regulating many target genes. Recent works have revealed that these nuclear receptors play critical roles in regulating genes that encode drug metabolism enzymes and modulating hepatic energy metabolism, such as down-regulating gluconeogenesis, fatty acid oxidation, and ketogenesis, as well as up-regulating lipogenesis. Studies on PXR and CAR have important implication on drug-drug interaction (DDI) and potential disease treatment targets.
Animals ; Drug Interactions ; Energy Metabolism ; Glucose ; metabolism ; Glucose-6-Phosphate ; metabolism ; Humans ; Inflammation ; metabolism ; Lipid Metabolism ; Liver ; metabolism ; NF-kappa B ; metabolism ; Receptors, Cytoplasmic and Nuclear ; physiology ; Receptors, Steroid ; physiology