Bile acids inhibit ferroptosis sensitivity through activating farnesoid X receptor in gastric cancer cells

BACKGROUND Gastric cancer(GC)is associated with high mortality rates.Bile acids(BAs)reflux is a well-known risk factor for GC,but the specific mechanism remains unclear.During GC development in both humans and animals,BAs serve as signaling molecules that induce metabolic reprogramming.This confers additional cancer phenotypes,including ferroptosis sensitivity.Ferroptosis is a novel mode of cell death characterized by lipid peroxidation that contributes universally to malignant progression.However,it is not fully defined if BAs can influence GC progression by modulating ferroptosis.AIM To reveal the mechanism of BAs regulation in ferroptosis of GC cells.METHODS In this study,we treated GC cells with various stimuli and evaluated the effect of BAs on the sensitivity to ferroptosis.We used gain and loss of function assays to examine the impacts of farnesoid X receptor(FXR)and BTB and CNC homology 1(BACH1)overexpression and knockdown to obtain further insights into the molecular mechanism involved.RESULTS Our data suggested that BAs could reverse erastin-induced ferroptosis in GC cells.This effect correlated with increased glutathione(GSH)concentrations,a reduced GSH to oxidized GSH ratio,and higher GSH peroxidase 4(GPX4)expression levels.Subsequently,we confirmed that BAs exerted these effects by activating FXR,which markedly increased the expression of GSH synthetase and GPX4.Notably,BACH1 was detected as an essential intermediate molecule in the promotion of GSH synthesis by BAs and FXR.Finally,our results suggested that FXR could significantly promote GC cell proliferation,which may be closely related to its anti-ferroptosis effect.CONCLUSION This study revealed for the first time that BAs could inhibit ferroptosis sensitivity through the FXR-BACH1-GSHGPX4 axis in GC cells.This work provided new insights into the mechanism associated with BA-mediated promotion of GC and may help identify potential therapeutic targets for GC patients with BAs reflux.

鹅去氧胆酸通过FXR调控高脂饮食诱导小鼠肠道GLP-1表达水平改善胰岛素抵抗的作用

目的 探究鹅去氧胆酸(chenodeoxycholic acid, CDCA)通过FXR对高脂饮食诱导小鼠肠道GLP-1表达水平的影响及相关机制。方法 C57BL/6小鼠40只分为对照组(Control组)、高脂饮食组(HFD组)、HFD+CDCA组、HFD+Z-Gug(FXR拮抗剂)组、HFD+CDCA+Z-Gug组,每组8只。干预8周,期间每周检测体质量及24 h摄食量。第8周进行口服葡萄糖耐量实验(OGTT)、腹腔葡萄糖耐量实验(IPGTT)。小鼠处死后,检测血清学指标GLu、TG、CHO、LDL-C、HDL-C;免疫荧光检测小鼠肠道组织GLP-1及FXR表达水平;RT-qPCR检测炎性因子TNF-α、IL-6、IL-1β、Gcg及FXR mRNA表达;ELISA试剂盒检测血清GLP-1含量;流式细胞术检测小肠IELs亚群比例及CD26/DPP4表达水平。结果 与Control组相比,HFD组小鼠体质量增加,血清糖脂代谢异常,口服糖耐量受损,胃肠激素分泌减弱(P<0.05);FXR mRNA及蛋白表达水平增加,Gcg mRNA表达及GLP-1分泌水平下降(P<0.05);肠道炎性因子TNF-α、IL-6、IL-1β mRNA表达水平升高(P<0.05);TCRαβ+IELs、TCRαβ+CD8αα+IELs与TCRαβ+CD8αβ+IELs细胞比例增加,TCRγδ+IELs比例下降,IELs总CD26/DPP4表达增加(P<0.05)。与HFD组相比,HFD+CDCA组小鼠体质量增加,口服糖耐量异常,胃肠激素分泌减弱(P<0.05);肠组织FXR mRNA及蛋白表达增加,Gcg mRNA表达及GLP-1分泌降低(P<0.05);肠道炎性因子表达降低,TCRαβ+IELs、TCRαβ+CD8αα+IELs与TCRαβ+CD8αβ+IELs细胞比例下降,TCRγδ+IELs占IELs比例升高,IELs总CD26/DPP4表达升高(P<0.05),以上作用在加入FXR拮抗剂Z-Gug后被明显抑制(P<0.05)。结论 CDCA可能通过激活FXR受体抑制肠道组织GLP-1表达,减少GLP-1分泌;同时可能抑制相关炎症因子表达调节IELs亚群比例,上调CD26/DPP4表达水平,促进GLP-1降解,加重胰岛素抵抗。

核受体FXR调控内质网应激途径缓解小鼠溃疡性结肠炎病理损伤

目的 探究法尼醇X受体(farnesoid X receptor,FXR)激活对溃疡性结肠炎(ulcerative colitis,UC)模型小鼠结肠组织病理损伤的影响及其作用机制。方法 将40只C57BL/6雄性健康小鼠随机分为对照组、模型组、奥贝胆酸(obeticholic acid,OCA)组、奥贝胆酸+衣霉素(OCA+TM)组,记录各组小鼠体质量、粪便性状与隐血程度、疾病活动指数(disease activity index,DAI)、剥离结肠长度。ELISA法检测各组小鼠血清IL-1β、IL-6、TNF-α含量,HE染色观察各组小鼠结肠组织病理形态变化,免疫组化染色检测各组小鼠结肠组织中GRP78和CCAAT/CHOP阳性表达情况,RT-qPCR和Western blotting检测各组小鼠结肠组织中GRP78和CHOP在mRNA与蛋白水平上的表达变化。结果 与对照组比较,模型组小鼠DAI升高,结肠长度缩短,血清中IL-1β、IL-6、TNF-α含量均增加,结肠组织发生明显损伤,可见广泛炎性细胞浸润,结肠组织中GRP78和CHOP阳性染色增强,GRP78和CHOP的mRNA相对表达量和蛋白相对表达量均上调(P<0.05);与模型组比较,OCA组小鼠DAI降低,结肠长度增加,血清中IL-1β、IL-6、TNF-α含量均减少,结肠组织损伤程度明显改善,未见炎性细胞浸润,结肠组织中GRP78和CHOP阳性染色减弱,且GRP78和CHOP的mRNA相对表达量与蛋白相对表达量均下调(P<0.05);而与OCA组比较,OCA+TM组小鼠DAI升高而结肠长度缩短,血清中IL-1β、IL-6、TNF-α含量也均增加,结肠组织损伤,表现出明显的溃疡现象,同时,结肠组织中GRP78和CHOP阳性染色增强,GRP78和CHOP的mRNA相对表达量与蛋白相对表达量也均上调(P<0.05)。结论 在UC小鼠模型中激活FXR能够有效缓解结肠组织病理损伤,该机制可能与调控内质网应激途径有关。

FXR激动剂在非酒精性脂肪性肝炎治疗中的研究进展

非酒精性脂肪性肝炎(Non-alcoholic steatohepatitis,NASH),又称代谢性脂肪性肝炎,是病理变化与酒精性肝炎相似但无过量饮酒史的临床综合征,好发于中年特别是超重肥胖个体。非酒精性脂肪性肝炎与肥胖、胰岛素抵抗、2型糖尿病、高脂血症等代谢紊乱关系密切,主要特征为肝细胞大泡性脂肪变伴肝细胞损伤和炎症,严重者可发展为肝硬化,但至今NASH尚无得到批准的治疗方案。在寻找有效的治疗方法时,解决代谢失调、炎症和抗纤维化的新策略不断涌现。法尼类X受体(Farnesoid X receptor,FXR)除了是胆汁酸代谢和肠肝循环的关键调节剂外,还参与调节代谢稳态,使其成为NASH中有吸引力的治疗靶点。本文综述了FXR激动剂对NASH治疗的研究进展。

沙棘熊果酸对酒精性肝损伤大鼠肝FXR信号通路的影响

目的:初步探讨沙棘熊果酸对酒精性肝损伤大鼠肝法尼醇X受体(Farnesoid X receptor,FXR)信号通路关键蛋白表达的影响。方法:6周龄SPF级SD大鼠随机分为4组,每组9只,分别为正常对照组、酒精模型组、熊果酸对照组和熊果酸+酒精组,干预时间为8周。采用苏木精-伊红(H&E)染色法观察大鼠肝组织病理学变化;测定大鼠血清中谷丙转氨酶(Alanine aminotransferase,ALT)、谷草转氨酶(Aspartateaminotransferase,AST)活力和血清总胆汁酸(Total bile acid,TBA)、肝脏甘油三酯(Triglyceride,TG)、总胆固醇(Total cholesterol,TC)含量;酶联免疫吸附(Enzyme linked immunosorbent assay,ELISA)法检测血清细胞因子肿瘤坏死因子α(Tumor necrosis factor-α,TNF-α)、白细胞介素1β(Interleukin 1β,IL-1β)、白细胞介素10(Interleukin 10,IL-10)含量;免疫印迹法(Western blotting)测定大鼠肝FXR信号通路相关蛋白表达情况。结果:与正常对照组相比,酒精模型组大鼠肝脏存在大小不一的脂肪空泡和大量炎性细胞浸润;血清ALT、AST活力,TNF-ɑ、IL-1β水平,TBA含量和肝脏TG、TC含量均显著升高(P<0.05)、IL-10水平显著下降(P<0.05)。经熊果酸干预后,肝脏脂肪变性得到明显改善,炎性细胞浸润减少;血清ALT、AST活力,TNF-α、IL-1β水平,TBA含量和肝脏TG含量均有不同程度的显著下降(P<0.05),IL-10水平显著提高(P<0.05)。Western blotting结果显示,与正常对照组相比,模型组大鼠肝脏FXR蛋白表达显著降低(P<0.05),CYP7A1和SREBP-1c蛋白表达均显著升高(P<0.05);而经熊果酸干预后,FXR蛋白表达明显提高,CYP7A1及SREBP-1c蛋白表达明显下调,且差异均具有统计学意义(P<0.05)。结论:沙棘熊果酸能够明显改善酒精诱导的肝脏损伤,其作用机制可能与上调肝FXR、抑制CYP7A1和SREBP-1c的蛋白表达,从而维胆汁酸稳态、调节脂质代谢有关。

FXR通过调控脂滴蛋白PLIN5延缓纤维化的调控机制

目的:本研究旨在揭示法尼醇X受体(farnesoid X receptor,FXR)通过调控脂滴包被蛋白5(perilipin 5, PLIN5)从而延缓肝纤维化的调控机制。方法:利用生物信息学预测PLIN5基因上游的FXR反应元件(FXR response element, FXRE),构建双荧光素酶报告基因体系以检测所预测位点与FXR的结合效应;使用转化生长因子-β1(transforming growth factor-β1, TGF-β1)诱导人肝星状细胞LX-2构建肝纤维化模型;过表达FXR或PLIN5后,qPCR和Western blot检测PLIN5、α平滑肌肌动蛋白(α-smooth muscle actin, α-SMA)和I型胶原蛋白(collagenⅠ)mRNA水平和蛋白水平;油红O染色检测脂滴的生成,定量检测甘油三酯(triglyceride,TG)的含量。结果:确定了PLIN5基因启动子区域含有已知的反向重复序列-1(inverted repeats-1,IR-1);FXR激活后能够上调LX-2中PLIN5的基因表达(P<0.01);过表达PLIN5能够促进脂滴的形成,TG含量的增加,并显著降低TGF-β1诱导的纤维化基因的表达(P<0.05);FXR激活后没有显示出抑制LX-2活化的作用。结论:PLIN5基因上游存在已知的FXRE位点能与FXR结合,PLIN5过表达能促进脂滴的形成和抑制LX-2细胞的活化,FXR可能是通过调控PLIN5的表达部分抑制肝纤维化。

肝细胞FXR对日本血吸虫感染小鼠肠道菌群的影响

目的分析肝细胞法尼醇X受体(farnesoid X receptor,FXR)特异性敲除对日本血吸虫感染小鼠肠道菌群的影响。方法6~8周龄野生型雄性C57BL/6J和肝细胞FXR特异性敲除小鼠(FXR-HKO)随机分为4组:野生型小鼠正常对照组(WT,n=5)、FXR-HKO小鼠正常对照组(FXR-HKO,n=6)、野生型小鼠日本血吸虫感染组(Sj-WT,n=6)、FXR-HKO小鼠日本血吸虫感染组(Sj-FXR-HKO,n=5)。其中,感染组每只小鼠感染(15±1)条日本血吸虫尾蚴,感染第5周处死小鼠,在无菌条件下收取小鼠结肠内容物,进行16S rDNA测序,比较各组之间的肠道菌群多样性和丰度差异。结果Beta多样性分析结果显示,Sj-WT组和Sj-FXR-HKO组小鼠的肠道菌群与正常小鼠肠道菌群有明显的分群。在门水平上,与正常对照组相比,Sj-WT组和Sj-FXR-HKO组小鼠肠道中拟杆菌门的丰度升高,厚壁菌门丰度降低,厚壁菌门与拟杆菌门丰度比值明显降低(均P<0.05)。在属水平上,与正常对照组相比,日本血吸虫感染后小鼠肠道中拟杆菌属的丰度明显升高(均P<0.05),Sj-FXR-HKO组拟杆菌属的丰度比Sj-WT组的升高更明显(P<0.05),其中Sj-WT组脱硫弧菌属、杜氏菌属、乳杆菌属的丰度显著降低(均P<0.05),Sj-FXR-HKO组瘤胃球菌科属、毛罗菌科、杜氏菌属、乳杆菌属的丰度明显降低(均P<0.05)。结论肝细胞FXR特异性敲除影响了日本血吸虫感染小鼠肠道菌群稳态,为后续进一步研究FXR-肠道菌群在血吸虫病中的作用及机制奠定了扎实的实验基础。

GW4064, a farnesoid X receptor agonist, upregulates adipokine expression in preadipocytes and HepG2 cells

AIM:To investigate the effect of GW4064 on the expression of adipokines and their receptors during differentiation of 3T3-L1 preadipocytes and in HepG2cells.METHODS:The mRNA expression of farnesoid X receptor(FXR),peroxisome proliferator-activated receptor-gamma 2(PPAR-γ2),adiponectin,leptin,resistin,adiponectin receptor 1(AdipoR1),adiponectin receptor2(AdipoR2),and the long isoform of leptin receptor(OB-Rb)and protein levels of adiponectin,leptin,andresistin were determined using fluorescent real-time PCR and enzyme linked immunosorbent assay,respectively,on days 0,2,4,6,and 8 during the differentiation of 3T3-L1 preadipocytes exposed to GW4064.Moreover,mRNA expression of AdipoR2 and OB-Rb was also examined using fluorescent real-time PCR at 0,12,24,and 48 h in HepG2 cells treated with GW4064.RESULTS:The mRNA expression of FXR,PPAR-γ2,adiponectin,leptin,resistin,AdipoR1,AdipoR2,and OB-Rb and protein levels of adiponectin,leptin,and resistin increased along with differentiation of 3T3-L1preadipocytes(P<0.05 for all).The mRNA expression of FXR,PPAR-γ2,adiponectin,leptin,and AdipoR2in 3T3-L1 preadipocytes,and AdipoR2 and OB-Rb in HepG2 cells was significantly increased after treatment with GW4064,when compared with the control group(P<0.05 for all).A similar trend was observed for protein levels of adipokines(including adiponectin,leptin and resistin).However,the expression of resistin,AdipoR1,and OB-Rb in 3T3-L1 cells did not change after treatment with GW4064.CONCLUSION:The FXR agonist through regulating,at least partially,the expression of adipokines and their receptors could offer an innovative way for counteracting the progress of metabolic diseases such as nonalcoholic fatty liver disease.

Recent insights into farnesoid X receptor in non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease(NAFLD) is the hepatic manifestation of metabolic syndrome and is one of the most prevalent liver disorders worldwide. NAFLD can gradually progress to liver inflammation, fibrosis, cirrhosis and even hepatocellular carcinoma. However, the pathogenesis of NAFLD is complex, and no efficient pharmaceutic treatments have yet been established for NAFLD. Accumulating data have shown that the farnesoid X receptor(FXR) plays important roles not only in bile acid metabolism, but also in lipid and carbohydrate homeostasis, inflammatory responses, among others. In this review, we aim to highlight the role of FXR in the pathogenesis and treatment of NAFLD.

Pravastatin activates the expression of farnesoid X receptor and liver X receptor alpha in Hep3B cells

BACKGROUND: Statins are suggested to preserve gallbladder function by suppressing pro-inflammatory cytokines and preventing cholesterol accumulation in gallbladder epithelial cells. They also affect cross-talk among the nuclear hormone receptors that regulate cholesterol-bile acid metabolism in the nuclei of hepatocytes. However, there is controversy over whether or how statins change the expression of peroxisome proliferator-activated receptor(PPAR)α, PPARγ, liver X receptor α(LXRα), farnesoid X receptor(FXR), ABCG5, ABCG8, and 7α-hydroxylase(CYP7A1) which are directly involved in the cholesterol saturation index in bile. METHODS: Human Hep3B cells were cultured on dishes. MTT assays were performed to determine the appropriate concentrations of reagents to be used. The protein expression of PPARα and PPARγ was measured by Western blotting analysis, and the mRNA expression of LXRα, FXR, ABCG5, ABCG8 and CYP7A1 was estimated by RT-PCR. RESULTS: In cultured Hep3B cells, pravastatin activated PPARα and PPARγ protein expression, induced stronger expression of PPARγ than that of PPARα, increased LXRα mRNA expression, activated ABCG5 and ABCG8 mRNA expression mediated by FXR as well as LXRα, enhanced FXR mRNA expression, and increased CYP7A1 mRNA expression mediated by the PPARγ and LXRα pathways, together or independently. CONCLUSION: Our data suggested that pravastatin prevents cholesterol gallstone diseases via the increase of FXR, LXRαand CYP7A1 in human hepatocytes.

A Cell-based High-throughput Screening Assay for Farnesoid X Receptor Agonists

Objective To develop a high-throughput screening assay for Farnesoid X receptor （FXR） agonists based on mammalian one-hybrid system （a chimera receptor gene system） for the purpose of identifying new lead compounds for dyslipidaemia drug from the chemical library. Methods cDNA encoding the human FXR ligand binding domain （LBD） was amplified by RT-PCR from a human liver total mRNA and fused to the DNA binding domain （DBD） of yeast GAL4 of pBIND to construct a GAL4-FXR （LBD） chimera expression plasmid. Five copies of the GAL4 DNA binding site were synthesized and inserted into upstream of the SV40 promoter of pGL3-promoter vector to construct a reporter plasmid pG5-SV40 Luc. The assay was developed by transient co-transfection with pG5-SV40 Luc reporter plasmid and pBIND-FXR-LBD （189-472） chimera expression plasmid. Results After optimization, CDCA, a FXR natural agonist, could induce expression of the luciferase gene in a dose-dependent manner, and had a signal/noise ratio of 10 and Z＇ factor value of 0.65, Conclusion A stable and sensitive cell-based high-throughput screening model can be used in high-throughput screening for FXR agonists from the synthetic and natural compound library.

Bile-acid-activated farnesoid X receptor regulates hydrogen sulfide production and hepatic microcirculation

AIM: To investigate whether the farnesoid X receptor (FXR) regulates expression of liver cystathionase (CSE), a gene involved in hydrogen sulfi de (H2S) generation. METHODS: The regulation of CSE expression in response to FXR ligands was evaluated in HepG2 cells and in wild-type and FXR null mice treated with 6-ethyl chenodeoxycholic acid (6E-CDCA), a synthetic FXR ligand. The analysis demonstrated an FXR responsive element in the 5'-flanking region of the human CSE gene. The function of this site was investigated by luciferase reporter assays, chromatin immunoprecipitation and electrophoretic mobility shift assays. Livers obtained from rats treated with carbon tetrachloride alone, or in combination with 6-ethyl chenodeoxycholic acid, were studied for hydrogen sulphide generation and portal pressure measurement. RESULTS: Liver expression of CSE is regulated by bile acids by means of an FXR-mediated mechanism. Western blotting, qualitative and quantitative polymerase chain reaction, as well as immunohistochemical analysis, showed that expression of CSE in HepG2 cells and in mice is induced by treatment with an FXR ligand. Administration of 6E-CDCA to carbon tetrachloride treated rats protected against the down-regulation of CSE expression, increased H2S generation, reduced portal pressure and attenuated the endothelial dysfunction of isolated and perfused cirrhotic rat livers. CONCLUSION: These results demonstrate that CSE is an FXR-regulated gene and provide a new molecular explanation for the pathophysiology of portal hypertension.

Mechanism of FXR alleviating the liver fibrosis by regulating perilipin 5

Objective:To investigate the regulatory mechanism in liver fibrosis progression by nuclear receptor of farnesoid X receptor(FXR)and the lipid droplet-associated protein of perilipin 5(PLIN5).Methods:FXR response element(FXRE)upstream of PLIN5 gene was found by bioinformatics,and confirmed by a dual luciferase reporter gene system;a hepatic fibrosis model based on human hepatic stellate cell LX-2 was established by induction of transforming growth factor-β1(TGF-β1);mRNA and protein levels ofα-smooth muscle actin(α-SMA)and collagen栺were measured by qPCR and Western blot after transient overexpression of FXR or PLIN5;Oil red O staining was used to study the formation of lipid droplets.Results:The promoter region of the PLIN5 gene contained a known reverse repeats-1(IR-1);the gene expression of PLIN5 in LX-2 cells was up-regulated after FXR activation(P<0.01);overexpression of PLIN5 promoted the formation of lipid droplets and significantly reduced the TGF-β1 induced fibrosis gene expression(P<0.05);FXR activation showed no effects on the inhibition of LX-2 cells activation.Conclusion:Overexpression of PLIN5 promotes the formation of lipid droplets and inhibits activation of LX-2 cells.FXR might bind to the FXRE site upstream of PLIN5 gene and regulate its gene expression.In summary,FXR may prevent liver fibrosis progression partially by regulating lipid droplet-associated protein of PLIN5.

Duodenal-jejunal bypass reduces serum ceramides via inhibiting intestinal bile acid-farnesoid X receptor pathway

BACKGROUND Bile acids play an important role in the amelioration of type 2 diabetes following duodenal-jejunal bypass(DJB).Serum bile acids are elevated postoperatively.However,the clinical relevance is not known.Bile acids in the peripheral circulation reflect the amount of bile acids in the gut.Therefore,a further investigation of luminal bile acids following DJB is of great significance.AIM To investigate changes of luminal bile acids following DJB.METHODS Salicylhydroxamic acid(SHAM),DJB,and DJB with oral chenodeoxycholic acid(CDCA)supplementation were performed in a high-fat-diet/streptozotocininduced diabetic rat model.Body weight,energy intake,oral glucose tolerance test,luminal bile acids,serum ceramides and intestinal ceramide synthesis were analyzed at week 12 postoperatively.RESULTS Compared to SHAM,DJB achieved rapid and durable improvement in glucose tolerance and led to increased total luminal bile acid concentrations with preferentially increased proportion of farnesoid X receptor(FXR)-inhibitory bile acids within the common limb.Intestinal ceramide synthesis was repressed with decreased serum ceramides,and this phenomenon could be partially antagonized by luminal supplementation of FXR activating bile acid CDCA.CONCLUSION DJB significantly changes luminal bile acid composition with increased proportion FXR-inhibitory bile acids and reduces serum ceramide levels.There observations suggest a novel mechanism of bile acids in metabolic regulation after DJB.

Farnesoid X receptor expression is reduced in human hepatocellular carcinoma

Farnesoid X receptor (FXR, NR1H4) is a member of nuclear hormone receptor superfamily. Previously studies showed that FXR-/- mice spontaneously developed liver tumors when they aged, however, the relevance of which to human hepatocellular carcinoma (HCC) is unclear. The aim of this study is to observe whether FXR expression is also downregulated in HCC and discuss the mechanism of the reduced FXR expression in HCC. Expression of FXR and small heterodimer partner (SHP) was measured by real-time PCR and immunohistochemical technique. Effect of pro-inflammatory cytokines on expression of FXR and its promoter activity were determined in primary hepatocytes or HepG2 and Huh7 cell lines. Our results showed that expression of FXR and its target gene SHP in human HCC was strongly downregulated compared to the normal liver tissues. In addition, pro-inflammatory cytokines were able to decrease FXR expression by inhibiting the FXR promoter activity. In conclusion this work demonstrates FXR expression is strongly downregulated in human HCC, which may be caused by decreased FXR promoter activity, suggesting a potential role of FXR in human HCC development.

Inhibition of cervical cancer cell proliferation and cervical tumorigenicity caused by farnesoid X receptor activation or over-expression is related to CDKN2A-p14^(ARF)-MDM2-p53 pathway

OBJECTIVE Cervical cancer is the third most malignant tumor in the world.Farnesoid X receptor(FXR) is a member of nuclear receptor superfamily.It is highly expressed in liver,kidney and small intestine,while it showed low expression level in other tissues.It not only plays an important role in the metabolism of bile acids and sugars,but also in the production of chronic inflammation in the early stage of cancer,the proliferation and migration of tumor.Compared with the normal tissue,the expression of FXR in most tumor tissues decreased.But there is no correlation between cervical cancer and FXR.So we aimed to find out the relationship between FXR and cervical cancer.METHODS A clinical study using q PCR,western blot and immunohistochemistry detected the expression of FXR in tumor tissues and normal tissues of clinical patients.FXR was activated by agonists or over-expressed by lentivirus.MTT,clone formation and flow cytometry were used to detect the relationship between FXR and proliferation of cervical cell lines.Tumor growth ability of FXR was detected by nude mice tumorigenicity.The interaction between FXR and CDKN2A-p14^(ARF)-MDM2-p53 pathway was detected by q PCR,Western blot and immunohistochemistry.RESULTS FXR was decreased in cancer tissues compared to normal control.Activation of FXR by agonist or constitutively-over-expression of FXR inhibited cervical cell proliferation.Over-expressed FXR attenuated Caski,Hela and Siha xenograft tumor growth in nude mice compared with control.Over-expression of FXR caused G1 cell-cycle arresting and up-regulated CDKN2A-p14^(ARF)-MDM2-p53 pathway.CONCLUSION FXR inhibits cervical cancer cell proliferation and cervical tumorigenicity which is related to CDKN2A-p14^(ARF)-MDM2-p53 pathway.Activation or overexpression of FXR may be a potential target for the treatment of cervical cancer.

高通量筛选研究茯砖茶对FXR模型的作用

将茯砖茶水提液分别用三氯甲烷、乙酸乙酯、正丁醇萃取,制得三氯甲烷层、乙酸乙酯层、正丁醇层及水层样品,茶渣用95%的乙醇提取,制得乙醇提取物,通过高通量药物筛选测定各样品对法尼酯衍生物X受体(FXR)模型的激活和抑制作用,研究茯砖茶的降脂减肥功效,结果显示茯砖茶各部份对FXR都有抑制作用,乙酸乙酯层样品激活作用较明显,从中分离制得儿茶素EGCG及ECG单体对FXR模型有很好的激活作用,证明茯砖茶有较强的降脂功能,有望开发成天然的降脂药物。茯砖茶中其他活性成分的分离有待进一步进行。

胆汁酸核受体FXR在非酒精性脂肪性肝病中的作用

非酒精性脂肪性肝病(nonalcoholic fatty liver disease,NAFLD)是以肝细胞脂肪变性和脂质沉积为特征,但无过量饮酒史、排外病毒感染和其他原因引起的肝脏疾病.NAFLD已成为一个全球关注的健康问题,其发病机制仍未阐明,尚无有效的药物治疗手段.法尼醇X受体(farnesoid X receptor,FXR)是需配体激活的转录因子,在胆汁酸、糖脂代谢中起着重要的调节作用.近年来研究显示FXR参与调控胰岛素抵抗(insulin resistance,I R)、脂质代谢异常、抑制肝星状细胞活化及炎症细胞渗入、促进肝内循环及肝细胞再生、延缓肝纤维化进程等NAFLD的重要环节.动物实验和临床研究也证实,FXR激动剂有延缓、治疗NAFLD的作用.提示FXR可能是NAFLD的潜在治疗靶点.目前,FXR应用于NAFLD仍存有争议.

胆汁酸受体FXR的研究进展

法尼酯衍生物X受体 (FXR)是一种胆汁酸受体 ,在胆汁酸代谢和胆固醇代谢中发挥重要作用 ,并有望成为降低胆固醇 ,治疗某些心血管病及肝脏疾病的治疗靶点。本文介绍了FXR的发现、FXR在调控胆汁酸和脂质代谢中的作用 ,以及FXR在心血管疾病治疗中的应用前景。

FXR、CYP7A1在妊娠期肝内胆汁淤积症孕鼠胆汁酸代谢中的作用

目的分析法尼醇受体(FXR)及其靶基因胆固醇7α-羟化酶(CYP7A1)在妊娠期肝内胆汁淤积症(intrahe-patic cholestasis of pregnancy,ICP)孕鼠肝脏的表达情况,探讨FXR与CYP7A1在ICP发病机制中的作用。方法用随机数字表法将30只孕15d的SD大鼠分成2组:生理盐水(NS)组和苯甲酸雌二醇(estradiol benzoate,EB)组,每组15只。用药前和用药后第5天分别测定血清中ALT、AST、ALP、TBA水平,同时观察肝脏形态学变化,并应用RT-PCR和Westernblot分别检测肝脏FXR、CYP7A1两者mRNA和蛋白的表达。结果EB组用药后各血清生化指标比用药前显著升高(P<0.01),NS组用药前后无明显变化(P>0.05);EB组孕鼠肝脏出现肝内胆汁淤积表现,NS组肝脏形态结构正常;EB组FXR和CYP7A1两者的mRNA和蛋白表达均显著高于NS组(P<0.01)。结论EB诱导的ICP孕鼠肝脏FXR及CYP7A1表达均增加,说明存在胆汁酸合成自身反馈调节障碍,导致胆汁酸合成增加,这可能是ICP发病机制之一。