Development and optimization of a cell screening system for farnesoid X receptor agonist / 生物工程学报

This study aims to develop an improved cell screening system for farnesoid X receptor (FXR) agonists based on a dual luciferase reporter gene system. FXR response element (FXRE) fragments from FXR target genes were cloned and inserted into upstream of firefly luciferase (Luc) gene in the plasmid pGL4-luc2P-Hygro. In combination with the internal reference plasmid containing renilla luciferase, a dual luciferase reporter gene system was developed and used for high throughput screening of FXR agonists. After studying the effects of over-expression of RXR, mouse or human FXR, various FXRE fragments, and different ratio of FXR plasmid amount to reporter gene plasmid, induction efficiency of the screening system was optimized by the known FXR agonist GW4064, and Z factor for the system reached 0.83 under optimized conditions. In summary, an improved cell screening system based on double luciferase reporter gene detection system was developed to facilitate the discovery of FXR agonists, where a new enhanced FXRE element was formed by a superposition of multiple FXRE fragments from FXR target genes, instead of a superposition of traditional IR-1 (inverted repeats-1) fragments.

Advances in traditional Chinese medicine treatment of non-alcoholic fatty liver disease via farnesoid X receptor / 中国中药杂志

Non-alcoholic fatty liver disease(NAFLD) is a chronic metabolic condition with rapidly increasing incidence, becoming a public health issue of worldwide concern. Studies have shown that farnesoid X receptor(FXR)-based modulation of downstream targets can improve liver function and metabolic status in the patients with NAFLD and may be a potential drug target for treating this di-sease. Great progress has been achieved in the development of drugs targeting FXR for the treatment of NAFLD. A number of studies have explored the traditional Chinese medicine and their active ingredients for the treatment of NAFLD via FXR considering the high safety and efficacy and mild side effects. This paper systematically describes the mechanism of traditional Chinese medicines in the treatment of NAFLD via FXR and the downstream targets, aiming to provide precise targets for the drug development and clinical treatment of NAFLD.

The role of nuclear receptor transcription factor NR2F6 in tumor / 生物工程学报

Nuclear receptor subfamily 2, group F, member 6 (NR2F6) is a member of orphan nuclear receptors, which is expressed in major tissues and organs of the human body, and plays an important role in the regulation of various biological functions and gene expressions. Recent studies have shown that the expression of NR2F6 was up-regulated in a variety of malignant tumors and showed significant correlations with cancer progression. These findings triggered the widespread interest in understanding the relationship between NR2F6 and cancer development and progression. In addition, the latest studies have underscored that NR2F6 was involved in enhancing antitumor immune responses that could serve as a potential target for immune regulation. This review summarizes the biological functions of NR2F6 and its role in tumors, with the aim to provide new insights into effective cancer therapies.

Farnesoid X receptor (FXR) inhibits coagulation process via inducing hepatic antithrombin III expression in mice / 生理学报

Farnesoid X receptor (FXR) has been identified as an inhibitor of platelet function and an inducer of fibrinogen protein complex. However, the regulatory mechanism of FXR in hemostatic system remains incompletely understood. In this study, we aimed to investigate the functions of FXR in regulating antithrombin III (AT III). C57BL/6 mice and FXR knockout (FXR KO) mice were treated with or without GW4064 (30 mg/kg per day). FXR activation significantly prolonged prothrombin time (PT) and activated partial thromboplastin time (APTT), lowered activity of activated factor X (FXa) and concentrations of thrombin-antithrombin complex (TAT) and activated factor II (FIIa), and increased level of AT III, whereas all of these effects were markedly reversed in FXR KO mice. In vivo, hepatic AT III mRNA and protein expression levels were up-regulated in wild-type mice after FXR activation, but down-regulated in FXR KO mice. In vitro study showed that FXR activation induced, while FXR knockdown inhibited, AT III expression in mouse primary hepatocytes. The luciferase assay and ChIP assay revealed that FXR can bind to the promoter region of AT III gene where FXR activation increased AT III transcription. These results suggest FXR activation inhibits coagulation process via inducing hepatic AT III expression in mice. The present study reveals a new role of FXR in hemostatic homeostasis and indicates that FXR might act as a potential therapeutic target for diseases related to hypercoagulation.

High Doses of Drugs Extensively Metabolized by CYP3A4 Were Needed to Reach Therapeutic Concentrations in Two Patients Taking Inducers / Dos pacientes que tomaban inductores necesitaron dosis altas de medicamentos metabolizados en gran medida por el CYP3A4 para alcanzar concentraciones terapéuticas

ABSTRACT Introduction: In the last 20 years of clinical practice, the senior author has identified these 2 rare cases in which the patients needed extremely high doses of drugs metabolized by CYP3A4 to reach and maintain serum therapeutic concentrations. Methods: The high metabolic ability of these 2 patients was demonstrated by the low concentration-to-dose ratios (C/D ratios) of several drugs metabolized by CYP3A4. Results: Case 1 was characterized by a history of high carbamazepine doses (up to 2,000 mg/day) and needed 170 mg/day of diazepam in 2 days to cooperate with dental cleaning. The high activity of the CYP3A4 isoenzyme was manifested by fast metabolism for quetiapine and diazepam, which took more than 1 year to normalize after the inducer, phenytoin, was stopped. Case 2 was also very sensitive to CYP3A4 inducers as indicated by very low C/D ratios for carbamazepine, risperidone and paliperidone. The carbamazepine (2,800 mg/day) and risperidone (20 mg/day) dosages for this second patient are the highest doses ever seen for these drugs by the senior author. Risperidone induction appeared to last for many months and metabolism was definitively normal 3 years after stopping carbamazepine. On the other hand, olanzapine C/D ratios were normal for induction. Conclusions: The literature has never described similar cases of very high doses of drugs metabolized by CYP3A4. We speculate that these 2 patients may have unusual genetic profiles at the nuclear receptor levels; these receptors regulate induction of drugs.

RESUMEN Introducción: Durante sus últimos 20 años de práctica, el último autor ha identificado estos 2 infrecuentes casos que necesitaban dosis extremadamente altas de medicaciones metabolizadas por el CYP3A4 para alcanzar y mantener concentraciones séricas terapéuticas. Métodos: La gran capacidad metabólica de estos 2 pacientes se demostró por los bajos cocientes entre concentración y dosis (C/D) de varias medicaciones metabolizadas por el CYP3A4. Resultados: El caso 1 se caracterizaba por una historia de altas dosis de carbamazepina (1.500 mg/día) y la necesidad de tomar 170 mg de diazepam en 2 días para facilitar una limpieza dental. La gran actividad de la isoenzima CYP3A4 se manifestó por una gran capacidad metabólica de quetiapina y diazepam, cuya normalización tardó más de 1 año tras la toma de un inductor, fenitoína. El caso 2 tambien era muy sensible a la inducción, lo cual se demuestra por los bajos cocientes C/D de carbamazepina, risperidona y paliperidona. Las dosis de carbamazepina (2.800 mg/día) y risperidona (20 mg/día) de este segundo paciente son las más altas nunca vistas por el último autor. La inducción de risperidona duró muchos meses y su metabolismo era normal 3 años después de interrumpir la carbamazepina. El cociente C/D de olanzapina era normal para la inducción. Conclusiones: Nunca se habían descrito casos similares de dosis tan altas de medicaciones metabolizadas por el CYP3A4. Se especula con que estos pacientes podrían tener unos perfiles genéticos inusuales en los receptores nucleares que regulan la inducción de medicamentos.

Association between decreased expression of estrogen receptor alpha, androgen receptor and phosphatase and tensin homolog immunoexpression in the canine prostate / Associação entre diminuição da expressão dos receptores de estrógeno alfa e andrógeno, e imunoexpressão de fosfatase e tensina homóloga na próstata canina

Canine prostate gland is a hormonal dependent organ and its imbalance of estrogen and androgen receptor expressions are directly associated with the development of different diseases. Due to the lack of information regarding the behavior of the aforementioned receptors in canine prostate cancer (PC), this study aimed to identify estrogen receptor alpha (ERα), androgen receptor (AR), Ki67 and phosphatase and tensin homolog (PTEN) protein expressions in canine PC by immunohistochemistry. We found nuclear expression of ERα and AR in the epithelial cells of normal canine samples and a loss of protein expression in PC samples. Normal samples showed Ki67 expression in a few basal cells and the PC samples showed the highest mean of positive cells (253.1). Canine prostate cancer showed a high proliferative index, which was associated with independence of hormonal actuation. PTEN showed positive nuclear and cytoplasmic expression in normal canine samples and a loss in PC. Loss of ERα, AR and PTEN indicated that canine PC exhibits the same immunohistochemical phenotype as in human patients with PC resistant to hormonal therapy. Therefore, canine PC should be considered as a model to study human PC resistant to hormonal therapy.(AU)

A glândula prostática canina é um órgão dependente de hormônio, e o desequilíbrio na expressão dos receptores de estrógeno e andrógeno estão diretamente associados com o desenvolvimento de diferentes doenças. Devido à falta de informação sobre o comportamento desses receptores no câncer prostático canino (PC), este estudo tem por objetivo identificar a expressão proteica através da técnica de imuno-histoquímica do receptor de estrógeno alfa (REα), receptor de andrógeno (RA), Ki67 e fosfatase e tensina homóloga (PTEN). Foi encontrado nas células epiteliais prostáticas normais caninas a expressão nuclear de REα e RA, e perda de expressão proteica nas amostras de PC. As amostras normais apresentaram expressão de Ki67 em poucas células basais e as amostras de PC apresentaram a maior média de células positivas (253,1). O câncer de próstata canino apresentou uma taxa alta de proliferação, o qual foi associado com a atuação independente de hormônio. As amostras de próstatas caninas normais revelaram marcação nuclear e citoplasmática da proteína PTEN e perda nas amostras de PC. A perda de REα, RA e PTEN indicam que as amostras de PC exibem o mesmo fenótipo imuno-histoquímico de pacientes humanos com câncer prostático resistente a terapia hormonal. Sendo assim, o PC canino deve ser considerado um modelo para estudos de câncer prostático humano resistente a terapia hormonal.(AU)

Understanding Bile Acid Signaling in Diabetes: From Pathophysiology to Therapeutic Targets

Diabetes and obesity have reached an epidemic status worldwide. Diabetes increases the risk for cardiovascular disease and non-alcoholic fatty liver disease. Primary bile acids are synthesized in hepatocytes and are transformed to secondary bile acids in the intestine by gut bacteria. Bile acids are nutrient sensors and metabolic integrators that regulate lipid, glucose, and energy homeostasis by activating nuclear farnesoid X receptor and membrane Takeda G protein-coupled receptor 5. Bile acids control gut bacteria overgrowth, species population, and protect the integrity of the intestinal barrier. Gut bacteria, in turn, control circulating bile acid composition and pool size. Dysregulation of bile acid homeostasis and dysbiosis causes diabetes and obesity. Targeting bile acid signaling and the gut microbiome have therapeutic potential for treating diabetes, obesity, and non-alcoholic fatty liver disease.

Effect of geniposidic acid on SHP-LRH-1 signaling pathway in cholestasis rats / 中南大学学报(医学版)

To explore the effect of geniposidic acid (GPA) on the signal pathway of small heterodimer dimer receptor (SHP) and liver receptor homologue 1 (LRH-1) in cholestasis rats induced by alpha-naphthalene isothiocyanate (ANIT).
 Methods: Fifty SD rats were randomly divided into five groups: a blank group, an ANIT group, an ANIT+GPA (100 mg/kg) group, an ANIT+GPA (50 mg/kg) group, and an ANIT+GPA (25 mg/kg) group (n=10 in each group). The GPA were intragastrically given to rats for 10 days, and the control group and the ANIT group were given normal saline. At the eighth day of administration, all rats except the blank group were given 65 mg/kg ANIT once until the tenth day. After the last administration, serum total cholesterol (TC), triglyceride (TG) and total bile acids (TBA) were measured. The primary hepatocytes (RPH) were isolated from normal rats and cultured. The cells were divided into a blank group, an ANIT (40 μmol/L) group, an ANIT (40 μmol/L)+GPA (4.00 mmol/L) group (A4.00G group), an ANIT (40 μmol/L)+GPA (1.00 mmol/L) group (A1.00G group), and an ANIT (40 μmol/L)+GPA (0.25 mmol/L) group (A0.25G group). The mRNA transcription levels of SHP and cholesterol 7 alpha hydroxylase (CYP7A1) in RPH were detected by real-time-PCR, and the protein levels of SHP and CYP7a1 were detected by Western blotting. In the LRH-1 silence experiment, the RPH were divided into a blank group, a negative transfection group, a siRNA-LRH group (ZR group), a siRNA-LRH+GPA (4.00 mmol/L) group (ZR4.00G group), a siRNA-LRH+GPA (1.00 mmol/L) group (ZR1.00G group) and a siRNA-LRH+GPA (0.25 mmol/L) group (ZR0.25G group). The protein and mRNA levels of SHP, CYP7a1, LRH-1 were detected. In the over-expression experiment, the RPH were also divided into a blank group, a negative transfection group, a LRH-1 over-expression plasmid group (OE group), a LRH-1 over-expression plasmid+GPA (4.00 mmol/L) group (OE4.00G group), a LRH-1 over-expression plasmid+GPA (1.00 mmol/L) group (OE1.00G group), and a LRH-1 over-expression plasmid+GPA (0.25 mmol/L) group (OE0.25G group). The protein and mRNA levels of SHP, CYP7a1 and LRH-1 were detected.
 Results: Compared with the blank control group, TC and TBA were significantly increased (both P<0.01) in the ANIT group, but there was no difference in TG; compared with the ANIT group, the contents of TC and TBA in the AG100 and AG50 groups were significantly reduced (all P<0.01). Compared with the blank control group, the proteins and mRNA levels of SHP were significantly decreased (P<0.01), while CYP7a1 were dramatically increased (P<0.01) in the ANIT group; compared with the ANIT group, the proteins and mRNA levels of SHP in the A4.00G group and the A1.00G group were significantly increased (both P<0.01), while the levels of CYP7a1 proteins and mRNA levels were evidently decreased in the A4.00G and A1.00G groups (both P<0.01). Compared with the negative transfection group, the proteins and mRNA levels of CYP7a1 and LRH-1 were dramatically restrained (all P<0.01), while there was no change in SHP in the ZR group; compared with the ZR group, the proteins and mRNA levels of SHP were significantly increased (all P<0.01), while LRH-1 and CYP7a1 were not changed in the ZR4.00G, ZR1.00G and ZR0.25G groups. Compared with the negative transfection group, the protein and mRNA levels of CYP7a1 and LRH-1 were significantly suppressed in the OE group (all P<0.01). Compared with the OE group, the protein and mRNA levels of SHP were evidently increased in the OE4G and OE1G groups (all P<0.01), while LRH-1 and CYP7a1 were not changed in the OE4G, OE1G and OE0.25G groups.
 Conclusion: The over-expression of LRH-1 in RPH can up-regulate the mRNA and protein levels of CYP7a1. GPA can improve the biochemical and liver pathology of ANIT-induced cholestasis rats, which may be related to the decrease of CYP7a1 by activating SHP through LRH-1 in RPH.

Regulation of bile acid metabolism-related signaling pathways by gut microbiota in diseases / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Over the past decade, there has been increasing attention on the interaction between microbiota and bile acid metabolism. Bile acids are not only involved in the metabolism of nutrients, but are also important in signal transduction for the regulation of host physiological activities. Microbial-regulated bile acid metabolism has been proven to affect many diseases, but there have not been many studies of disease regulation by microbial receptor signaling pathways. This review considers findings of recent research on the core roles of farnesoid X receptor (FXR), G protein-coupled bile acid receptor (TGR5), and vitamin D receptor (VDR) signaling pathways in microbial-host interactions in health and disease. Studying the relationship between these pathways can help us understand the pathogenesis of human diseases, and lead to new solutions for their treatments.

Enrichment of Short-Chain Ceramides and Free Fatty Acids in the Skin Epidermis, Liver, and Kidneys of db/db Mice, a Type 2 Diabetes Mellitus Model

Patients with diabetes mellitus (DM) often suffer from diverse skin disorders, which might be attributable to skin barrier dysfunction. To explore the role of lipid alterations in the epidermis in DM skin disorders, we quantitated 49 lipids (34 ceramides, 14 free fatty acids (FFAs), and cholesterol) in the skin epidermis, liver, and kidneys of db/db mice, a Type 2 DM model, using UPLC-MS/MS. The expression of genes involved in lipid synthesis was also evaluated. With the full establishment of hyperglycemia at the age of 20 weeks, remarkable lipid enrichment was noted in the skin of the db/db mice, especially at the epidermis and subcutaneous fat bed. Prominent increases in the ceramides and FFAs (>3 fold) with short or medium chains (

Analysis of LBR gene mutation in a pedigree affected with Pelger-Huёt anomaly / 中华医学遗传学杂志

OBJECTIVE@#To detect mutation of LBR gene in a pedigree affected with Pelger-Huёt anomaly (PHA) and to explore its clinical characteristics.@*METHODS@#Genomic DNA was extracted from the pedigree and healthy controls. The 14 exons of the LBR gene were subjected to PCR amplification and Sanger sequencing. Suspected mutations were verified in other family members and 100 healthy controls. Polyphen-2 and SIFT software were used to predict the effect of the mutation, and Swiss-model software was used to simulate the protein structure.@*RESULTS@#Three patients were found to carry a c.893G>A mutation in exon 8 of the LBR gene, which resulted in substitution of the 298th amino acid residue glycine by glutamic acid (p.Gly298Glu). The same mutation was not found in healthy family members and 100 healthy controls. The mutation was predicted to be damaging. Bioinformatic simulation showed the mutation has altered the 3D structure of the LBR protein.@*CONCLUSION@#The c.893G>A (p.Gly298Glu) mutation in the LBR gene probably underlies the PHA in this pedigree and has enriched the spectrum of LBR gene mutations.

Effect of geniposidic acid on hepato-enteric circulation in cholestasis rats through Sirt1-FXR signaling pathway / 中国中药杂志

To investigate the effects of geniposidic acid( GPA) on hepato-enteric circulation in cholestasis rats,and to explore the mechanism based on the sirtuin 1( Sirt1)-farnesol X receptor( FXR) pathway,sixty SD rats were randomly divided into 6 groups:blank control group,ANIT model group,ursodeoxycholic acid group( 100 mg·kg~(-1)·d-1 UDCA),and GPA high,medium and low( 100,50 and 25 mg·kg~(-1)·d-1) dosage groups,10 rats in each group. Corresponding drugs were intragastrically( ig) administered for10 days. After administration on day 8,all rats except blank rats were administered with 65 mg·kg~(-1)α-naphthalene isothiocyanate( ANIT) once. After the last administration,the serum levels of alanine aminotransferase( ALT),glutamine oxalacetate aminotransferase( AST),gamma-glutamyltransferase( γ-GGT),alkaline phosphatase( ALP),total bilirubin( TB) and total bile acid( TBA)were measured,and the mRNA transcription levels of Sirt1,FXR,multidrug resistant associated protein 2( MRP2),bile salt export pump( BSEP),sodium taurocholate contractible polypeptide( NTCP) in liver and apical sodium bile acid transporter( ASBT),ileum bile acid binding protein( IBABP) in ileum were detected by reverse transcription-polymerase chain reaction( RT-PCR). The protein expression levels of Sirt1,FXR and NTCP were detected by Western blot; the expression of MRP2,BSEP in liver and ASBT,IBABP in ileum were determined by immunofluorescence three staining. Primary rat hepatocytes were cultured in vitro to investigate the inhibitory effect of GPA on a potent and selective Sirt1 inhibitor( EX 527),and the mRNA and protein expression levels of Sirt1 and FXR were detected by RT-PCR and Western blot. GPA significantly decreased the levels of ALT,AST,γ-GGT,ALP,TB,TBA in serum( P<0.01) and improved the pathological damage of liver tissues in ANIT-induced cholestasis rats; significantly increased the mRNA and protein expression levels of Sirt1,FXR,MRP2,BSEP,NTCP in liver and ASBT,IBABP in ileum( P< 0.01). In vitro primary hepatocytes experiment indicated that the gene and protein expression levels of FXR and Sirt1 were noticeably improved by GPA in primary hepatocytes inhibited by EX-527( P<0.01). It was found that the improvement of GPA was in a dose-dependent manner. GPA could improve bile acid hepatointestinal circulation and play a liver protection and cholagogu role in cholestasis rats induced by ANIT.The mechanism may be that GPA activated FXR by regulating Sirt1,a key regulator of oxidative stress injury,and then the activated FXR could regulate protein of bile acid hepato-enteric circulation.

Hypolipidemic effect of SIPI-7623, a derivative of an extract from oriental wormwood, through farnesoid X receptor antagonism / 中国天然药物

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.

Bile acids and their effects on diabetes / 医学前沿

Diabetes is a widespread, rapidly increasing metabolic disease that is driven by hyperglycemia. Early glycemic control is of primary importance to avoid vascular complications including development of retinal disorders leading to blindness, end-stage renal disease, and accelerated atherosclerosis with a higher risk of myocardial infarction, stroke and limb amputations. Even after hyperglycemia has been brought under control, "metabolic memory," a cluster of irreversible metabolic changes that allow diabetes to progress, may persist depending on the duration of hyperglycemia. Manipulation of bile acid (BA) receptors and the BA pool have been shown to be useful in establishing glycemic control in diabetes due to their ability to regulate energy metabolism by binding and activating nuclear transcription factors such as farnesoid X receptor (FXR) in liver and intestine as well as the G-protein coupled receptor, TGR5, in enteroendocrine cells and pancreatic β-cells. The downstream targets of BA activated FXR, FGF15/21, are also important for glucose/insulin homeostasis. In this review we will discuss the effect of BAs on glucose and lipid metabolism and explore recent research on establishing glycemic control in diabetes through the manipulation of BAs and their receptors in the liver, intestine and pancreas, alteration of the enterohepatic circulation, bariatric surgery and alignment of circadian rhythms.

Hypolipidemic effect of SIPI-7623, a derivative of an extract from oriental wormwood, through farnesoid X receptor antagonism / 中国天然药物

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.

Nuclear receptors and renal water transport regulation / 生理学报

The function of kidney is maintaining water balance of our body through regulation of urine concentration and dilution. The aquaporins are molecular basis of renal urine production and water transport, and their expression and membrane translocation are regulated delicately. Nuclear receptors are a superfamily of ligand-activated transcription factors consisting of 48 members in human. They widely participate in a variety of physiological and pathophysiological regulation including growth and development, glucose and lipid metabolism, inflammation, immunology by regulating target gene transcription and expression. Increasing evidence demonstrates that these receptors are involved in the regulation of aquaporins expression and membrane translocation in kidney, thereby playing a major role in water homeostasis. Here we review the role of nuclear receptors in regulating renal water transport.

MAFB mediates the therapeutic effect of sleeve gastrectomy for obese diabetes mellitus by activation of FXR expression

Farnesoid X receptor (FXR) and related pathways are involved in the therapeutic effect of sleeve gastrectomy for overweight or obese patients with diabetes mellitus. This study aimed to investigate the mechanism of FXR expression regulation during the surgical treatment of obese diabetes mellitus by sleeve gastrectomy. Diabetic rats were established by combined streptozotocin and high-fat diet induction. Data collection included body weight, chemical indexes of glucose and lipid metabolism, liver function, and the expression levels of musculoaponeurotic fibrosarcoma oncogene family B (MAFB), FXR, and related genes induced by sleeve gastrectomy. Chang liver cells overexpressing MAFB gene were established to confirm the expression of related genes. The binding and activation of FXR gene by MAFB were tested by Chip and luciferase reporter gene assays. Vertical sleeve gastrectomy induced significant weight loss and decreased blood glucose and lipids in diabetic rat livers, as well as decreased lipid deposition and recovered lipid function. The expression of MAFB, FXR, and FXR-regulated genes in diabetic rat livers were also restored by sleeve gastrectomy. Overexpression of MAFB in Chang liver cells led to FXR gene expression activation and the alteration of multiple FXR-regulated genes. Chip assay showed that MAFB could directly bind with FXR promoter, and the activation of FXR expression was confirmed by luciferase reporter gene analysis. The therapeutic effect of sleeve gastrectomy for overweight or obese patients with diabetes mellitus was mediated by activation of FXR expression through the binding of MAFB transcription factor.

Antifibrotic effect of total flavonoids of Astmgali Radix on dimethylnitrosamine-induced liver cirrhosis in rats / 中国结合医学杂志

<p><b>OBJECTIVE</b>To 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).</p><p><b>METHODS</b>Fifty-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.</p><p><b>RESULTS</b>Compared 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).</p><p><b>CONCLUSION</b>TFA 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.</p>

Nr2e1 Downregulation Is Involved in Excess Retinoic Acid-induced Developmental Abnormality in the Mouse Brain / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>This 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.</p><p><b>METHODS</b>The 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.</p><p><b>RESULTS</b>Nr2e1 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.</p><p><b>CONCLUSION</b>Our study demonstrated that Nr2e1 could be regulated by RA, which would aid a better understanding of the mechanism underlying RA-induced brain abnormality.</p>

Nuclear Receptors Resolve Endoplasmic Reticulum Stress to Improve Hepatic Insulin Resistance

Chronic endoplasmic reticulum (ER) stress culminating in proteotoxicity contributes to the development of insulin resistance and progression to type 2 diabetes mellitus. Pharmacologic interventions targeting several different nuclear receptors have emerged as potential treatments for insulin resistance. The mechanistic basis for these antidiabetic effects has primarily been attributed to multiple metabolic and inflammatory functions. Here we review recent advances in our understanding of the association of ER stress with insulin resistance and the role of nuclear receptors in promoting ER stress resolution and improving insulin resistance in the liver.