SIRT1 activation synergizes with FXR agonism in hepatoprotection via governing nucleocytoplasmic shuttling and degradation of FXR

Farnesoid X receptor (FXR) is widely accepted as a promising target for various liver diseases; however, panels of ligands in drug development show limited clinical benefits, without a clear mechanism. Here, we reveal that acetylation initiates and orchestrates FXR nucleocytoplasmic shuttling and then enhances degradation by the cytosolic E3 ligase CHIP under conditions of liver injury, which represents the major culprit that limits the clinical benefits of FXR agonists against liver diseases. Upon inflammatory and apoptotic stimulation, enhanced FXR acetylation at K217, closed to the nuclear location signal, blocks its recognition by importin KPNA3, thereby preventing its nuclear import. Concomitantly, reduced phosphorylation at T442 within the nuclear export signals promotes its recognition by exportin CRM1, and thereby facilitating FXR export to the cytosol. Acetylation governs nucleocytoplasmic shuttling of FXR, resulting in enhanced cytosolic retention of FXR that is amenable to degradation by CHIP. SIRT1 activators reduce FXR acetylation and prevent its cytosolic degradation. More importantly, SIRT1 activators synergize with FXR agonists in combating acute and chronic liver injuries. In conclusion, these findings innovate a promising strategy to develop therapeutics against liver diseases by combining SIRT1 activators and FXR agonists.

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.

Effect of Modified Da Chaihutang on FXR/FGF15/FGFR4 Signaling Pathway in Mice with Cholesterol Gallstone Differentiated into Damp-Heat Syndrome / 中国实验方剂学杂志

ObjectiveTo observe the effect of modified Da Chaihutang on cholesterol gallstone （CS） in mice due to damp-heat based on the farnesoid X receptor （FXR）/fibroblast growth factor 15 （FGF15）/fibroblast growth factor receptor 4 （FGFR4） pathway and explore the molecular biological mechanisms of CS differentiated into damp-heat syndrome from the perspective of correspondence between prescription and syndrome. MethodForty-eight six-week-old mice were randomly divided into the blank group， model group， modified Da Chaihutang （23.4 g·kg-1） group， and ursodeoxycholic acid （0.12 g·kg-1） group， with 12 mice in each group. The ones in the latter three groups were exposed to "internal dampness + external dampness + high-cholesterol diet" for 12 weeks for inducing CS due to damp-heat. Mice in the modified Da Chaihutang group and ursodeoxycholic acid group were gavaged with the corresponding drugs， while those in the model and blank groups with the same amount of normal saline for a total of four weeks. Before and after modeling， mice in each group were subjected to open field tests for determining their activities and mental states. Such general conditions as body mass， food intake， fur， and urine and stool of mice in each group were observed and recorded weekly for judging the damp-heat syndrome. After the intervention， the sampled liver and gallbladder tissues of mice in each group were stained with hematoxylin-eosin （HE） staining， and the serum γ-glutamyltransferase （GGT）， alkaline phosphatase （ALP）， and total bilirubin （TBIL） were determined. The total cholesterol （TC） and total bile acid （TBA） contents in bile were measured by enzyme-linked immunosorbent assay （ELISA）. The mRNA and protein expression levels of FXR， FGF15， FGFR4， and cholesterol 7α-hydroxylase gene （CYP7A1） were assayed by real-time fluorescence quantitative polynucleotide chain reaction （Real-time PCR） and Western blot. ResultCompared with the blank group， the model group exhibited enlarged gallbladder， brown turbid bile with flocculent precipitation visible to the naked eye， obvious damp-heat syndrome， lipoid degeneration in the liver tissue， rough and thickened gallbladder wall， elevated ALP， GGT， and TBIL in serum （P<0.01） and TC in bile （P<0.01）， reduced TBA （P<0.01）， up-regulated FXR， FGF15， and FGFR4 mRNA and protein expression in ileum （P<0.05， P<0.01）， and down-regulated CYP7A1 mRNA and protein expression （P<0.01）. Compared with the model group， the two medication groups displayed improved bile turbidity， and the bile in the modified Da Chaihutang group became clearer. After intervention， the damp-heat syndrome of mice in the modified Da Chaihutang group was significantly alleviated. The liver and gallbladder lesions of mice in the two medication groups were significantly relieved， manifested as reduced serum ALP， GGT， and TBIL （P<0.01）. The reduction in ALP and TBIL of the modified Da Chaihutang group was more significant （P<0.01）. The TC contents in the bile of mice from the two medication groups were significantly lowered， whereas the TBA contents were elevated （P<0.01）， with more significant changes present in the modified Da Chaihutang group （P<0.01）. The mRNA and protein expression levels of FXR， FGF15， and FGFR4 in the modified Da Chaihutang group were down-regulated （P<0.05， P<0.01）， while the mRNA and protein expression levels of CYP7A1 rose （P<0.05）， except that the elevation in FGF15 and FGFR4 protein expression and reduction in CYP7A1 protein expression were not significant. The mRNA and protein expression levels of FXR， FGF15， and FGFR4 in the ursodeoxycholic acid group all decreased， among which the reduction in FXR was remarkable （P<0.05）， and the mRNA and protein expression levels of CYP7A1 were significantly up-regulated （P<0.05）. ConclusionModified Da Chaihutang significantly improves the stone， liver function， bile composition， abnormal cholesterol-bile acid metabolism， and damp-heat syndrome in the model mice of CS differentiated into damp-heat syndrome， which may be related to its regulation of key factors FXR， FGF15， FGFR4， and CYP7A1 mRNA and protein expression in the cholesterol-bile acid metabolism pathway.

Improvement effect and mechanism of ethanol extract from Citri Reticulatae Pericarpium on triglyceride in hyperlipidemia model rat / 中国中药杂志

The aim of this paper was to study the improvement effect of ethanol extract from Citri Reticulatae Pericarpium(CRP) on triglyceride of hyperlipidemia model rats, and to explore the possible mechanism. SD rats were randomly divided into normal group, model group, positive control group, and high, medium and low-dose CRP ethanol extract groups, with 10 rats in each group. During the experiment, except for the normal group that was fed with distilled water and ordinary feed, rats in the other groups were given different concentrations of alcohol and fed with high-sugar and fat diets. All rats were given free diets. While being modeled, each group was administered with 0.01 mL·g~(-1) by gavage once a day for six weeks. Blood samples were collected after two weeks, four weeks and six weeks of drug treatment. After the completion of the experiment, blood, liver and adipose tissue were collected. Triglyceride(TG), alanine aminotransferase(ALT), aspartate aminotransferase(AST), alkaline phosphatase(ALP) in serum, TG in liver tissue and TG in fecal were detected. Free fatty acid(FFA) and triglyceride-related hydrolase, such as adipose tiglyceride lipase(ATGL), lipoprotein lipase(LPL), hepatic lipase(HL), hormone-sensitive triglyceride lipase(HSL) were detected by ELISA. The mRNA expressions of peroxisome proliferators-activated receptors(PPARγ), sterol regulatory element binding protein 1 c(SREBP-1 c) and farnesoid X receptor(FXR) were determined by RT-PCR. Compared with the model group, each administration group could reduce TG levels in serum and liver to varying degrees, reduce serum ALT, AST, ALP activities, significantly reduce free fatty acid content in serum, significantly increase triglyceride metabolism-related enzymes, including fat ATGL, LPL and liver HL content, and significantly reduced the content of fat HSL. According to the study of transcriptional regulation genes relating to triglyceride metabolism, extract from CRP could significantly increase the mRNA expressions of PPARγ and FXR. In conclusion, ethanol extract from CRP could ob-viously reduce the TG level of hyperlipidemia model rats, and might reduce plasma TG content by increasing PPARγ-LPL/ATGL and FXR-HL triglyceride hydrolysis pathways.

Baicalin protects against 17α-ethinylestradiol-induced cholestasis via Sirt1/HNF-1α/FXR pathway / 中国药理学与毒理学杂志

OBJECTIVE Baicalin is a major flavonoid component of Scutellaria baicalensis, and has been used in the treatment of liver diseases for many years. However, the role of baicalin in estrogen-induced cholestasis (EIC) remains to be elucidated. This present study explored the protective effect of baicalin against estrogen-induced liver injury and further elucidated the mechanisms involved both in vivo and in vitro. METHODS We conducted a series of experiments using 17α-ethinylestradiol (EE) induced cholestatic rats and cultured HepG2 cells. Serum, bile, and liver samples were collected for biochemical and histological analyses. Bile acid composition in liver was analyzed by LC-MS/MS. The mechanisms underlying the hepatoprotective of baicalin were investigated by RT-PCR, Western blotting analyses and immunohistochemistry. RESULTS Baicalin showed obvious hepatoprotective effects in EIC rats by reducing serum bio?markers and increasing the bile flow rate, as well as by alleviating liver histology and restoring the abnormal composition of hepatic bile acids (BAs). In addition, baicalin protected against EE induced liver injury by up-regulation of the expres?sion of hepatic efflux transporters and down-regulation of hepatic uptake transporters. Furthermore, baicalin increased the expression of hepatic BA synthase (CYP27A1) and metabolic enzymes (Bal, Baat and Sult2a1) in EIC rats. We showed that baicalin significantly inhibited hepatic inflammatory responses in EIC rats through reducing elevated levels of TNF-α, IL-1β, IL-6 and NF-κB. Finally, we confirmed that baicalin maintains BA homeostasis and alleviates inflamma?tion through Sirt1/HNF-1α/FXR signaling pathway. CONCLUSION Baicalin protects against estrogen-induced cholestatic liver injury, and the underlying mechanism involved is related to activation of the Sirt1/HNF-1α/FXR signaling pathway.

Effect of Shuangyu Tiaozhi Decoction on SRB1/CYP7A1/FXR Signaling Pathway in Liver of Hypercholesterolemic Rats / 中国实验方剂学杂志

Objective:To observe the effect of Shuangyu Tiaozhi decoction on B-type scavenger receptor （SRB1）/cholesterol 7<italic>α</italic>-hydroxylase protein （CYP7A1）/farnesol X receptor （FXR） signaling pathway in liver of hypercholesterolemic rats， and its mechanism in reducing blood lipid. Method:Among 40 SD rats， 8 were randomly selected as normal group， and the remaining 32 were successfully established as hypercholesterolemic model， and randomly divided into 4 groups： model group， low and high-dose Shuangyu Tiaozhi decoction groups （7.8， 15.6 g·kg^-1）， and simvastatin group （4 mg·kg^-1）， with 8 rats in each group. The drugs were continuously given for 8 weeks. Serum total cholesterol （TC）， triglyceride （TG） and liver TC，free cholesterol （FC） and total bile acid （TBA） were measured. The pathomorphological changes in liver were observed by Hematoxylin and eosin （HE） Staining. The mRNA and protein expressions of SRB1， CYP7A1 and FXR were determined by Real-time fluorescence quantitative polymerase chain reaction （Real-time PCR） and Western blot. The immunohistochemistry was used to detect CYP7A1 and FXR expressions in liver. Result:Compared with the normal group， TC， TG， FC levels in the model group were significantly increased， while the TBA level was markedly decreased， the morphology showed obvious liver steatosis， and significant declines in expressions of SRB1， CYP7A1， FXR were observed by Real-time PCR， Western blot and immunohistochemistry assays （<italic>P</italic><0.05， <italic>P</italic><0.01）. Compared with the model group， the levels of TC，TG，FC in each treatment group were reduced significantly， and the TBA level was increased markedly， the liver steatosis decreased significantly， the results of Real-time PCR， Western blot and immunohistochemistry assays showed significant increase in the expressions of SRB1， CYP7A1， FXR （<italic>P</italic><0.05， <italic>P</italic><0.01）. The therapeutic effect of high-dose Shuangyu Tiaozhi decoction group was more remarkable than that in low-dose Shuangyu Tiaozhi Decoction group （<italic>P</italic><0.05）， with no obvious difference compared with simvastatin group. Conclusion:Shuangyu Tiaozhi decoction can promote hepatic RCT and synthesize bile acid by up-regulating SRB1/CYP7A1/FXR signaling pathway， so as to reduce the blood lipid levels and improve hepatic lipid metabolism of hypercholesterolemic rats.

Research on Therapeutic Mechanism of Canhuang Tablets on Jaundiced Rats Induced by ANIT / 中国实验方剂学杂志

Objective:To explore the therapeutic mechanism of Canhuang tablets on the mRNA and protein expression of farnesoid X receptor (FXR), uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1) and multidrug resistance associated protein 2 (MRP2) in the liver of jaundiced rats induced by α-naphthalene isothiocyanate (ANIT). Method:The rats were divided into normal group, model group, Canhuang tablets (CHP) group and ursodeoxycholic acid tablets (UDCA) group. The jaundice model was reproduced by ANIT. After the intervention of the corresponding drugs, the contents of total bilirubin (TBIL), total bile acid (TBA), alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP) in serum and the liver histopathology were examined to evaluate the therapeutic effect of CHP. The relative mRNA and protein expressions of FXR, UGT1A1 and MRP2 in rat liver tissues were detected by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot. Result:CHP can significantly reduce the increase of TBIL, TBA, ALT, AST and ALP caused by ANIT in rat serum, and inhibit the liver pathological changes, which showed that the removing jaundice effect of CHP was better than UDCA. Compared with the normal group, ANIT significantly inhibited the mRNA levels of FXR, UGT1A1 and MRP2 in rat liver tissues after modeling (P<0.01). Compared with the model group, CHP and UDCA significantly increased the mRNA levels of target genes of each protein after intervention (P<0.01), and CHP was superior to UDCA in improving the mRNA level of bilirubin metabolizing enzyme UGT1A1 (P<0.01). In the aspect of affecting protein expression, compared with the normal group, ANIT modeling significantly increased the expression of FXR in rats (P<0.05). CHP intervention showed a tendency to promote the expression of FXR, while UDCA did not, but there was no significant difference between them. In the aspects of promoting bilirubin metabolism and bile excretion, the expressions of UGT1A1 and MRP2 were significantly decreased by ANIT modeling (P<0.01), while the expressions of UGT1A1 and MRP2 proteins were significantly increased after treatment of CHP (P<0.01). CHP was superior to UDCA in increasing the expression of bilirubin and bile acid efflux protein MRP2 (P<0.01). Conclusion:The jaundice abating mechanism of CHP is related to activating FXR mRNA expression in liver, promoting the mRNA and protein expression of bilirubin metabolizing enzyme UGT1A1 and bile acid transporter MRP2, improving liver metabolism of free bilirubin and promoting bile acid excretion from the liver, and alleviating cholestatic liver injury.

Mechanism of Cinnamomi Ramulus improving rat model of intrahepatic cholestasis induced by ANIT by regulating FXR pathway / 中国中药杂志

To study the mechanism and action of Cinnamomi Ramulus in ameliorating intrahepatic cholestasis induced by α-isothiocyanate( ANIT) in rats by regulating FXR pathway. Forty SD rats were randomly divided into normal group,model group,positive control( ursodeoxycholic acid) group( 60 mg·kg~(-1)),Cinnamomi Ramulus treatment( 60 mg·kg~(-1)·d~(-1)) group,and Cinnamomi Ramulus treatment( 20 mg·kg~(-1)·d~(-1)) group,with 8 rats in each group. Except for the normal control group,the other groups were intragastrically administered with the corresponding concentrations of continuous aqueous solution( 0. 005 m L·g~(-1)),once a day,for 7 days.Except for the normal group,the other groups were treated with ANIT( 100 mg·kg~(-1)),once a day,for 3 days. Blood was taken from the abdominal aorta 24 hours after the last administration,and serum alanine aminotransferase( ALT),aspartate aminotransferase( AST),total bilirubin( TBi L),and total bile acid( TBA) were measured. 1. 5-2 cm of rat liver tissue was taken. After fixation with10% formaldehyde,paraffin-embedded sections were taken,HE staining was performed,and immunohistochemistry( IHC) was used to analyze the expression of FXR. RNA and protein were extracted from rat liver tissue to detect FXR mRNA expression,as well as bile acid synthesis and detoxification,transport related SHP,UGT2 B4,BSEP protein expressions at downstream of FXR. Compared with the normal group,serum ALT,AST,TBi L,and TBA levels were elevated in the model group( P<0. 01),liver damage was severe,FXR protein's optical density decreased,FXR mRNA expression decreased,and SHP,UGT2 B4,BSEP protein expressions were decreased( P<0. 05,P<0. 01). Compared with the model group,the drug group could reduce serum ALT,AST,TB,TBA levels to different degrees( P<0. 05,P<0. 01),alleviate liver tissue damage,increase the optical density of FXR protein,and promote the expressions of FXR mRNA and FXR,SHP,BSEP and UGT2 B4 proteins( P<0. 05,P<0. 01). Cinnamomi Ramulus can alleviate ANIT-induced intrahepatic cholestasis,and reduce hepatocyte injury and serum ALT,AST,TBi L and TBA levels. The mechanism may be through FXR-SHP,FXR-UGT2 B4,FXR-BSEP signaling pathways. Therefore,in the pathogenesis of intrahepatic cholestasis,we can try to further explore in alleviating intrahepatic cholestasis with Cinnamomi Ramulus,so as to provide effective drugs for clinical treatment of intrahepatic cholestasis.

Alterations in bile acid levels in metabolic diseases and related treatment strategies / 上海交通大学学报（医学版）

Bile acid as a signaling molecule can specifically bind to bile acid receptors (such as farnesoid X receptor and G-protein-coupled bile acid receptor) to mediate a series of biological regulation reactions. In recent years, it has been found that bile acids are widely involved in glucose metabolism, lipid metabolism and energy metabolism. The development of metabolic diseases is usually accompanied by the changes of bile acid profiles and receptors, and thus bile acids may be applied as potential biomarkers for clinical diagnosis, prediction, and evaluation of therapeutic effects. This article reviews the relationship between bile acids and metabolic diseases, and the treatment of metabolic diseases based on the regulation of bile acid metabolism.

Role of farnesol X receptor in glycolipid metabolism regulation / 上海交通大学学报（医学版）

Farnesol X receptor (FXR), also known as bile acid nuclear receptor, is a ligand-dependent nuclear transcription factor distributed in multiple tissues and organs such as liver and intestinal tract. And bile acid is its endogenous natural ligand. Recent studies have shown that intestinal FXR plays an indispensable role in glycolipid metabolism regulation, and intestinal specific FXR agonists or antagonists can participate in glucose and lipid metabolism regulation in vivo. In this paper, the role of intestinal FXR in glycolipid metabolism reported in recent years is systematically reviewed.

Protective effect and regulating effect on FXR/SHP gene of electroacupuncture preconditioning on myocardial ischemia-reperfusion injury in rats / 中国针灸

OBJECTIVE@#To explore the protective mechanism of electroacupuncture preconditioning on myocardial ischemia-reperfusion injury in rats.@*METHODS@#A total of 88 SPF-grade Wistar male rats were randomized into a normal group, a sham-operation group, a model group and an electroacupuncture (EA) group, 22 rats in each one. The rats in the normal group received normal diet and no intervention was given for 7 d. The rats in the sham-operation and the model group were bound for 20 min, once a day for 7 d. In the EA group, EA, continuous wave, 2 Hz and 1 mA, was applied at "Neiguan" (PC 6), "Zusanli" (ST 36) and "Guanyuan" (CV 4) for 20 min, once a day for 7 d. In the 8th day, the blood was collected by abdominal aortic method 60 min after intraperitoneal injection of 10% urethane anesthesia by 10 mL/kg in the normal group, and then the tissue of heart was collected. In the model group and the EA group, ligating the left anterior descending coronary artery (LAD) was adopted for 20 min and reperfusion was applied for 40 min, then the samples were collected. The rats in the sham-operation group recevied open-chest operation and no other intervention, the samples were collected in 60 min. Nitro Blue Tetrazolium Chloride monohydrate (NBT) stain was used to detected myocardial infarct size and weight, ELISA was used to measured myocardial injury markers and inflammatory factors (LDH、CK、cTnI), and the fluorescent quantitative PCR method was used to determine the expressions of FXR and SHP gene.@*RESULTS@#①There was no significant difference between the normal group and the sham-operation group in myocardial infarct size and weight (>0.05) .Compared with the normal group, myocardial infarct size and weight were higher in the model group (0.05). Compared with the normal group, the serum contents of LDH、CK、cTnI were higher in the model group (<0.05). Compared with the model group, the serum contents of LDH、CK、cTnI were lower in the EA group (<0.05). ③The expressions of FXR and SHP gene in the model group were higher than those in the normal group (<0.05). The expressions of FXR and SHP gene in the EA group were lower than those in the model group (<0.05).@*CONCLUSION@#Electroacupuncture preconditioning could significantly improve cardiac function of rats with myocardial ischemia-reperfusion, reduce infarct size and inflammatory factors, and down-regulate the expressions of FXR and SHP gene. The protective effect may generate based on regulation of FXR/SHP apoptosis signal pathway.

FXR expression is associated with the prognosis and pathological staging of patients with pancreatic cancer / 基础医学与临床

Objective To explore the correlation among farnesoid X receptor (FXR), clinical stage and survival time of patients with pancreatic cancer. Methods The total protein and mRNA were extracted from cultured 8 pan-creatic cancer cell lines,and the expression level of FXR in pancreatic cancer cells was detected by Western bolt and real-time PCR. We collected 5 cases of normal pancreatic tissue and 50 cases of pancreatic cancer tissues,and used immunohistochemistry method to detect FRX expression in normal pancreatic tissue and pancreatic cancer. Ac-cording to the different expression level of FXR,these 50 patients were divided into low expression group and high expression group, the correlation of clinical data and FRX expression level was analyzed. Furthermore, Kaplan-Meier and log-rank analysis of prognostic factors was assessed in a multivariable analysis using a Cox proportional hazards model. Results FXR was differently expressed in 8 pancreatic cancer cell lines and pancreatic cancer tis-sues. FXR was closely related to the pathological G stage of pancreatic cancer(P＜0.05). FXR and pathological G stage were significantly correlated with the patients' survival time. The survival time of the patients with high FXR expression was significantly longer than that of patients with low FXR expression (P＜0.05). Conclusions The expression of FXR is closely related to the pathological G stage in patients with pancreatic cancer. Both FXR expression and pathological G stage are independent prognostic factors in patients with pancreatic cancer.

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.

Expressions of Bile Acid Receptor FXR and TGR5 in Patients with Ulcerative Colitis / 胃肠病学

Background:The incidence of ulcerative colitis (UC)in developed countries is higher than that in developing countries,which may be related with westernized lifestyle,especially high animal protein and low complex carbohydrate diet. With the increased high fat and meat intake,synthesis and secretion of bile acid in liver is also increased,which may have an impact on the occurrence of UC. Aims:To investigate the expressions of farnesoid X receptor (FXR)and G protein-coupled bile acid receptor 5 (TGR5)in patients with UC. Methods:Thirty patients with active UC from January 2013 to June 2016 at the Affiliated Jiangning Hospital of Nanjing Medical University were enrolled,and 30 healthy subjects were served as controls. Expressions of FXR and TGR5 were determined by immunohistochemistry. Results:Compared with control group,expression of FXR was significantly decreased in UC patients (4. 63 ± 2. 07 vs. 6. 91 ± 2. 62,P =0. 00),however,no significant difference in expression of TGR5 was found between the two groups (6. 70 ± 2. 90 vs. 6. 11 ± 2. 44,P = 0. 40). Expression of FXR was significantly increased in right hemicolon colitis than in left hemicolon colitis (P < 0. 05). Conclusions:There is a significant decrease in FXR in active UC patients,indicating that FXR may have some role in the pathogenesis of UC,however,TGR5 may have no obvious effect in the pathogenesis of UC.

Progress on roles and mechanisms of farnesoid X receptor (FXR) in chronic liver diseases / 中国药理学通报

Farnesoid X receptor ( FXR) plays a key role in me-tabolism of substance, such as bile acid, lipid, glucose,( etc) . Newly published credible discoveries have claimed that as a reg-ulatory hub in metabolism, FXR is closely linked with diverse chronic liver diseases, including viral hepatitis, alcoholic fatty liver disease, nonalcoholic fatty liver disease, hepatic fibrosis and hepatocellular carcinoma. This review summarizes the roles and mechanisms of FXR during the courses of chronic liver dis-eases, aiming at providing novel insights and therapeutic target for antifibrotic research and drug development.

Effects of the total flavonoids of scutellaria barbataon on atherosclerosis and expression of PLTP in ApoE gene deficiency mice / 中国药理学通报

Aim To observe the effects of the total fla-vonoids of scutellaria barbataon ( TFSB ) on high-fat feeding ApoE gene deficiency mice in early atheroscle-rosis ( AS ) and its underlying mechanisms. Methods 40 ApoE-/ -male mice were divided into five groups:model group, SIM group and L-TFSB, M-TFSB, H-TFSB group, 5 C57BL/6J mice were selected as nor-mal control group. All mice in experimental group were fed with high-lipid diet for 4 weeks and all mice were killed after 8 weeks. H&E staining was used to observe morphology of aorta. Blood rheometer was used to ex-amine plasm viscosity and whole blood viscosity. Fully automatic biochemical analyser was used to detect the serum levels of TG, TC, LDL-C and HDL-C. The ex-pression levels of PLTP and VE in serum were meas-ured by ELISA. The expression levels of PLTP and FXR in liver were examined by Western blot. Results The model was established successfully. TFSB groups could improve the aorta AS morphology of model mice and significantly reduce the serum levels of TG, TC and LDL-C, while increase the level of HDL-C ( P hematocrit value, plasma viscosity and whole blood vis-cosity of AS model mice significantly and had statistical significance when compared with model group ( P <0. 01 ) . The expression levels of PLTP of serum were reduced significantly when compared with model group ( P <0. 01 ) . We also found that the expression of PLTP was in negative correlation with VE ( r = -0. 675,P<0. 01). M-TFSB and H-TFSB group could decrease the expressions of PLTP and FXR of liver when compared with model group ( P <0. 01 ) . Con-clusion TFSB may exert its anti-AS effect partly through inhibiting the levels of FXR and PLTP of ApoE-/ -mice, increasing the level of VE, regulating blood lipids, improving blood rheology and reducing the damage of AS in mice.

Effects of FXR gene deletion on neurobehaviors and neurotransmission systems in female mice / 中国药理学通报

Aim To investigate how Farnesoid X re-ceptor (FXR),a nuclear hormone receptor,acts on neurological behaviors such as emotion,social behav-ior,memory and so on.Methods FXR’s function in central nervous system was evaluated by conducting a battery of behavioral tests including elevated plus maze test (EPMT),forced-swimming test (FST),social in-teraction test (SIT ), and passive avoidance test (PAT),and the contents of neurotransmitters were de-termined by the LC-MS /MS method in FXR knockout (KO)female mice and their wild-type controls.Re-sults FXR KO mice showed significantly increased immobility time in FST (P <0.01 ),and it showed in-creased tendency to enter the open arms in EMPT (P<0.01 ).The number of probing the open arms by FXR KO mice was more than that of the controls.Mo-reover,in SIT,FXR KO mice had remarkably in-creased sniffing interactions with the stranger mouse in the same cage (P <0.01 ).But in PAT,the latency for FXR KO mice to enter the dark chamber on the test day and the number of FXR KO mice to enter the dark chamber didn’t differ from those wild-type mice.In hippocampus,the contents of GABA,Glu,and NE were decreased prominently in FXR KO mice (P <0.05,P <0.05 and P <0.01 ,respectively)as well as the ratio of GABA to Glu (P <0.05).But in pre-frontal cortex,none of the neurotransmitters examined showed any difference between FXR KO mice and their controls.Conclusion FXR may be involved in main-tenance of the homeostasis of neural transmission in the central nervous system,thereby influences the emotion-al and social behavior in animals.

Establishment of cell models for PXR, FXR and LXRαagonists high-throughput screening based on reporter gene assay / 中国药理学通报

Aim To develop an in vitro high throughput drug screening system based on reporter gene assay for identification of novel compounds with PXR, FXR and LXRα agonist activity. Methods The expressions of exogenous PXR, FXR and LXRαgene in HEK293, HepG2 and LS174T cells were examined by Real-Time quantity PCR. pSG5-hPXR and pGL3-XREM-CYP3A4, pEGFP-N3-hFXR and EcRE-TK-Luc, pCMX-FLAG-hLXRα and pGL3-XREM-CYP3A4 were cotransfected into cells and the optimal ratio of three plasmids was determined. The dose-response relationship between the positive drug and the fold induction was determined. The specificity of the model was ex-amined, and the repeatability was also determined by Z′ value. Results ① The PXR, FXR and LXRα mRNA expression in HEK293 cell is low among three different cells. ②reporter gene vector and expression plasmid ratio of 1∶ 1, 2∶ 1 and 2∶ 1 were proved to be suitable for highest relative luciferase activity for PXR, FXR or LXRα agonist screening model. ③ The relative luciferase activity was induced by Rif, CDCA or T0901317 in a dose-dependent manner. ④Only Rif, CDCA or T0901317 could significantly increase the relative luciferase activity in PXR,FXR or LXRα agonist screening model, no effect of other nuclear re-ceptors agonist was observed, and the values of Z′-factor for PXR, FXR and LXRαagonist screening model were 0. 58, 0. 66 and 0. 63, respectively. Conclusion An in vitro PXR, FXR and LXRα agonist high-throughput screening models are devel-oped with acceptable specificity and repeatability, and the mod-els can be used to screen PXR, FXR and LXRα agonist.

Nuclear receptors as drug targets in cholestasis / 中国药理学通报

Drug for cholestasis therapy is extremely limited.Ur-sodeoxycholic acid is currently the only FDA approved drug to treat primary biliary cirrhosis,whereas its efficacy is limited to early stage of the disease.Therefore,developing novel drugs re-presents a major goal for both pharmaceutical industry and aca-demic researchers.Targeting nuclear receptors in cholestasis is an intriguing approach since these receptors are critically in-volved in the regulation of bile acid homeostasis.This review summarizes the roles of individual nuclear receptors in cholestasis and evaluates their potential clinical application.

Bile Acid Diarrhea: Prevalence, Pathogenesis, and Therapy

Bile acid diarrhea (BAD) is usually seen in patients with ileal Crohn's disease or ileal resection. However, 25% to 50% of patients with functional diarrhea or diarrhea-predominant irritable bowel syndrome (IBS-D) also have evidence of BAD. It is estimated that 1% of the population may have BAD. The causes of BAD include a deficiency in fibroblast growth factor 19 (FGF-19), a hormone produced in enterocytes that regulates hepatic bile acid (BA) synthesis. Other potential causes include genetic variations that affect the proteins involved in BA enterohepatic circulation and synthesis or in the TGR5 receptor that mediates the actions of BA in colonic secretion and motility. BAs enhance mucosal permeability, induce water and electrolyte secretion, and accelerate colonic transit partly by stimulating propulsive high-amplitude colonic contractions. There is an increased proportion of primary BAs in the stool of patients with IBS-D, and some changes in the fecal microbiome have been described. There are several methods of diagnosing BAD, such as 75selenium homotaurocholic acid test retention, serum C4, FGF-19, and fecal BA measurement; presently, therapeutic trials with BA sequestrants are most commonly used for diagnosis. Management involves the use of BA sequestrants including cholestyramine, colestipol, and colesevelam. FXR agonists such as obeticholic acid constitute a promising new approach to treating BAD.