Advances in drug resistance of triple negative breast cancer caused by pregnane X receptor

Breast cancer is the most common malignancy in women worldwide.Triplenegative breast cancer(TNBC),refers breast cancer negative for estrogen receptor,progesterone receptor and human epidermal growth factor receptor 2,characterized by high drug resistance,high metastasis and high recurrence,treatment of which is a difficult problem in the clinical treatment of breast cancer.In order to better treat TNBC clinically,it is a very urgent task to explore the mechanism of TNBC resistance in basic breast cancer research.Pregnane X receptor(PXR)is a nuclear receptor whose main biological function is to participate in the metabolism,transport and clearance of allobiological agents in PXR.PXR plays an important role in drug metabolism and clearance,and PXR is highly expressed in tumor tissues of TNBC patients,which is related to the prognosis of breast cancer patients.This reviews synthesized the important role of PXR in the process of high drug resistance to TNBC chemotherapeutic drugs and related research progress.

Liver X receptors and epididymal epithelium physiology

Aim： To investigate the roles of liver X receptors （LXR） in the lipid composition and gene expression regulation in the murine caput epididymidis. LXR are nuclear receptors for oxysterols, molecules derived from cholesterol metabolism that are present in mammals as two isoforms： LXRα, which is more specifically expressed in lipid-metabolising tissues, such as liver, adipose and steroidogenic tissues, and macrophages, whereas LXRβ is ubiquitous. Their importance in reproductive physiology has been sustained by the fact that male mice in which the function of both LXR has been disrupted have fertility disturbances starting at the age of 5 months, leading to complete sterility by the age of 9 months. These defects are associated with epididymal epithelial degeneration in caput segments one and two, and with a sperm midpiece fragility, leading to the presence of isolated sperm heads and flagella when luminal contents are recovered from the cauda epididymidis. Methods： The lipid composition of the caput epididymidis of wild-type and LXR-deficient mice was assessed using oil red O staining on tissue cryosections and lipid extraction followed by high performance liquid chromatography or gas chromatography. Gene expression was checked by quantitative real time polymerase chain reaction. Results： Using LXR-deficient mice, we showed an alteration of the lipid composition of the caput epididymidis as well as a significantly decreased expression of the genes encoding SREBPlc, SCD1 and SCD2, involved in fatty acid metabolism. Conclusion： Altogether, these results show that LXR are important regulators of epididymal function, and play a critical role in the lipid maturation processes occurring during sperm epididymal maturation. （Asian J Androl 2007 July; 9： 574-582）

Role of P2X_7 receptors in neuronal death in the retina

Acknowledgments： I would like to express my appreciation to Professor Puro DG for leading me to this research topic during my stay as a research fellow in his laboratory at the University of Michigan in 2001, and also to Professor Ikeda T forgiving me the opportunity to study abroad and then to continue to investigate this topic in the Department of Ophthalmology at Osaka Medical College, lapan.

P2X receptors in maintenance and differentiation of neural progenitor cells

Purinergic receptors are among the first cell surface receptors expressed during embryonic development （Burnstock and Ulrich, 2011）. These are characterized based on their pharmacological properties of being activated by adenosine or purine/pyrimidine nucleotides as P1 and P2 receptors. P2 receptors are further classified by their structure as P2Y metabotropic and P2X ionotropic receptors.

Role of liver X receptors alpha agonist on expressions of LPS-induced inflammatory response associated factor IRAK-4 and NF-kappaB in Kupffer cells

Objective： To explore the role of activated liver X receptor α （LXRα） on the expressions of interleukin-1 receptor associated kinase-4 （IRAK-4） and NF-kappaB （NF-κB） in the inflammatory response which induced by LPS in the Kupffer cells and to investigate the possible mechanisms of LXRα negative regulation of inflammatory response. Methods： The Kupffer cells were isolated from male Kunming mice by collagen perfusion in situ. And these cells were divided into 4 groups： normal control group, LPS treatment group, LXRct agonist T0901317 treatment group, LPS and T0901317 combined treatment group. The LPS treatment group were treated with a final concentration of 1 μg/ml LPS in RPMI 1640 and cultured for 6 h, the T0901317 treatment group were treated with a final concentration of 5 μg/ml in RPMI 1640 and cultured for 24 h, and the combined treatment group received pre-culture for 24 h with a final concentration of 1μg/ml T0901317 in RPMI 1640 and then cultured for 6 h with a final concentration of 5 μg/ml LPS in RPMI 1640. All groups were cultured for 30 h. The expression of LXRα, IRAK-4 and NF-κB at mRNA and protein levels were detected by real-time PCR and Western blotting, and the TNF-α and IL-1β levels were detected by ELISA. Results： The levels of LXRα mRNA and protein were highest in T0901317 group, and lowest in LPS group （P〈0.05）. The level of IRAK4 and NF-κB mRNAs and proteins were evidently lower in the Combined-treated group than in LPS group （P〈0.05）. And the level of TNF-α and IL-1 were observed highest in LPS group （P〈0.05）, but no difference among the Control group, T0901317 group and Combined-treated group （P〉0.05）. Conclusion： These date suggest that the LXR agonists can effectively up-regulate the expressions of LXRα mRNA and protein and inhibit the inflammatory response. This may be via down-regulating the expressions of IRAK4 and NF-κB at mRNA and protein levels.

Regulation of neural stem/progenitor cell functions by P2X and P2Y receptors

Neural stem/progenitor cells：Radial glial cells constitute multipotent cells in the ventricular zone,lining the wall of the lateral ventricle of the embryonic brain.They have the capacity to give rise to cells belonging to all three major linages（neurons,astrocytes and oligodendrocytes）of the nervous system（Tang and Illes,2017）.

Role of pregnane X-receptor in regulating bacterial translocation in chronic liver diseases

Bacterial translocation(BT) has been impeccably implicated as a driving factor in the pathogenesis of a spectrum of chronic liver diseases(CLD). Scientific evidence accumulated over the last four decades has implied that the disease pathologies in CLD and BT are connected as a loop in the gut-liver axis and exacerbate each other. Pregnane X receptor(PXR) is a ligandactivated transcription factor and nuclear receptor that is expressed ubiquitously along the gut-liver-axis. PXR has been intricately associated with the regulation of various mechanisms attributed in causing BT. The importance of PXR as the mechanistic linker molecule in the gutliver axis and its role in regulating bacterial interactions with the host in CLD has not been explored. Pub Med was used to perform an extensive literature search using the keywords PXR and bacterial translocation, PXR and chronic liver disease including cirrhosis. In an adequate expression state, PXR acts as a sensor for bile acid dysregulation and bacterial derived metabolites, and in response shapes the immune profile beneficial to the host. Activation of PXR could be therapeutic in CLD as it counter-regulates endotoxin mediated inflammation and maintains the integrity of intestinal epithelium. This review mainly focuses PXR function and its regulation in BT in the context of chronic liver diseases.

Role of P2X_7 receptors in the development of diabetic retinopathy

The P2X7 receptor is one of the members of the family of purinoceptors which are ligand-gated membrane ion channels activated by extracellular adenosine 5'-triphosphate. A unique feature of the P2X7 receptor is that its activation can result in the formation of large plasma membrane pores that allow not only the flux of ions but also of hydrophilic molecules of up to 900 Da. Recent studies indicate that P2X7-mediated signaling can trigger apoptotic cell death after ischemia and during the course of certain neurodegenerative disorders. Expression of the P2X7 receptor has been demonstrated in most types of cells in the retina. This purinoceptor mediates the contraction of pericytes and regulates the spatial and temporal dynamics of the vasomotor response through cell-to-cell electrotonic transmission within the microvascular networks. Of potential clinical significance, investigators have found that diabetes markedly boosts the vulnerability of retinal microvessels to the lethal effect of P2X7 receptor activation. This purinergic vasotoxicity may result in reduced retinal blood flow and disrupted vascular function in the diabetic retina. With recent reports indicating an association between P2X7 receptor activation and inflammatory cytokine expression in the retina, this receptor may also exacerbate the development of diabetic retinopathy by a mechanism involving inflammation.

Nuclear receptors and pathogenesis of pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is a devastating disease with a median overall survival time of 5 mo and the five years survival less than 5%, a rate essentially unchanged over the course of the years. A well defined progression model of accumulation of genetic alterations ranging from single point mutations to gross chromosomal abnormalities has been introduced to describe the origin of this disease. However, due to the its subtle nature and concurring events PDAC cure remains elusive. Nuclear receptors (NR) are members of a large superfamily of evolutionarily conserved ligand-regulated DNA-binding transcription factors functionally involved in important cellular functions ranging from regulation of metabolism, to growth and development. Given the nature of their ligands, NR are very tempting drug targets and their pharmacological modulation has been widely exploited for the treatment of metabolic and inflammatory diseases. There are now clear evidences that both classical ligand-activated and orphan NR are involved in the pathogenesis of PDAC from its very early stages; nonetheless many aspects of their role are not fully understood. The purpose of this review is to highlight the striking connections that link peroxisome proliferator activated receptors, retinoic acid receptors, retinoid X receptor, androgen receptor, estrogen receptors and the orphan NR Nur, chicken ovalbumin upstream promoter transcription factor II and the liver receptor homologue-1 receptor to PDAC development, connections that could lead to the identification of novel therapies for this disease.

Microcantilever-based Nanomechanical Studies of the Orphan Nuclear Receptor Pregnane X Receptor-Ligand Interactions

Human pregnane X receptor (PXR) is of vital importance in pharmaceutical and exogenous compound metabolism within the body. This provides strong motivation for investigating this orphan receptor’s activation by various pharmaceuticals, xenobiotics, and endocrine disrupting chemicals (EDCs). A nanomechanical transducer is developed to study xenobiotic and EDC interactions with the bioreceptor PXR’s ligand binding domain (LBD). The combination of immobilized LBD PXR with a nanostructured microcantilever (MC) platform allows for the sensitive, label-free study of ligand interaction with the receptor. PXR shows real-time, reversible responses when exposed to a specific pharmaceutical, EDCs, and xenobiotic ligands. Three EDCs binding interactions are tested, which include phthalic acid, nonylphenol, and bisphenol A, with PXR. PXR LBD was exposed to rifampicin, a potent PXR activator, with various injection and recovery times to study their interaction. A two protein array of PXR and estrogen receptor ? (ER-?) directly compares the nanomechanical responses of these receptors with rifampicin on a single platform.

Bile acid receptors and nonalcoholic fatty liver disease

With the high prevalence of obesity, diabetes, and otherfeatures of the metabolic syndrome in United States, nonalcoholic fatty liver disease(NAFLD) has inevitably become a very prevalent chronic liver disease and is now emerging as one of the leading indications for liver transplantation. Insulin resistance and derangement of lipid metabolism, accompanied by activation of the pro-inflammatory response and fibrogenesis, are essential pathways in the development of the more clinically significant form of NAFLD, known as nonalcoholic steatohepatitis(NASH). Recent advances in the functional characterization of bile acid receptors, such as farnesoid X receptor(FXR) and transmembrane G protein-coupled receptor(TGR) 5, have provided further insight in the pathophysiology of NASH and have led to the development of potential therapeutic targets for NAFLD and NASH. Beyond maintaining bile acid metabolism, FXR and TGR5 also regulate lipid metabolism, maintain glucose homeostasis, increase energy expenditure, and ameliorate hepatic inflammation. These intriguing features have been exploited to develop bile acid analogues to target pathways in NAFLD and NASH pathogenesis. This review provides a brief overview of the pathogenesis of NAFLD and NASH, and then delves into the biological functions of bile acid receptors, particularly with respect to NASH pathogenesis, with a description of the associated experimental data, and, finally, we discuss the prospects of bile acid analogues in the treatment of NAFLD and NASH.

Hepatic drug transporters and nuclear receptors:Regulation by therapeutic agents

The canalicular membrane represents the excretory pole of hepatocytes.Bile is an important route of elimination of potentially toxic endo-and xenobiotics(including drugs and toxins),mediated by the major canalicular transporters:multidrug resistance protein 1(MDR1, ABCB1),also known as P-glycoprotein,multidrug resistance-associated protein 2(MRP2,ABCC2),and the breast cancer resistance protein(BCRP,ABCG2).Their activities depend on regulation of expression and proper localization at the canalicular membrane,as regulated by transcriptional and post-transcriptional events,respectively.At transcriptional level,specific nuclear receptors(NR)s modulated by ligands,co-activators and co-repressors,mediate the physiological requirements of these transporters.This complex system is also responsible for alterations occurring in specific liver pathologies.We briefly describe the major ClassⅡNRs, pregnane X receptor(PXR)and constitutive androstane receptor(CAR),and their role in regulating expression of multidrug resistance proteins.Several therapeutic agents regulate the expression of relevant drug transporters through activation/inactivation of these NRs.We provide some representative examples of the action of therapeutic agents modulating liver drug transporters, which in addition,involve CAR or PXR as mediators.

Effect of Marine Collagen Peptides on Markers of Metabolic Nuclear Receptors in Type 2 Diabetic Patients with/without Hypertension

Objective To explore Effects of marine collagen peptides （MCPs） on markers of metablic nuclear receptors, i.e peroxisome proliferator-activated receptor （PPARs）, liver X receptor （LXRs） and farnesoid X receptor （FXRs） in type 2 diabetic patients with/without hypertension. Method Study population consisted of 200 type 2 diabetic patients with/without hypertension and 50 healthy subjects, all of whom were randomly assigned to MCPs-treated diabetics （n=50）, placebo-treated diabetics （n=50）, MCPs-treated diabetics with hypertension （n=50）, placebo-treated diabetics with hypertension （n=50）, and healthy controls （n=50）. MCPs or placebo （water-soluble starch） were given daily before breakfast and bedtime over three months. Levels of free fatty acid, cytochrome P450, leptin, resistin, adiponectin, bradykinin, NO, and Prostacyclin were determined before intervention, and 1.5 months, and 3 months after intervention. Hypoglycemia and the endpoint events during the study were recorded and compared among the study groups. Result At the end of the study period, MCPs-treated patients showed marked improvement compared with patients receiving placebo. The protection exerted by MCPs seemed more profound in diabetics than in diabetics with hypertension. In particular, after MCPs intervention, levels of free fatty acid, hs-CRP, resistin, Prostacyclin decreased significantly in diabetics and tended to decrease in diabetic and hypertensive patients whereas levels of cytochrome P450, leptin, NO tended to decrease in diabetics with/without hypertension. Meanwhile, levels of adiponectin and bradykinin rose markedly in diabetics following MCPs administration. Conclusion MCPs could offer protection against diabetes and hypertension by affecting levels of molecules involved in diabetic and hypertensive pathogenesis. Regulation on metabolic nuclear receptors by MCPs may be the possible underlying mechanism for its observed effects in the study. Further study into its action may shed light on development of new drugs based on bioactive peptides from marine sources.

Triggering of Major Brain Disorders by Protons and ATP:The Role of ASICs and P2X Receptors

Adenosine triphosphate(ATP)is well-known as a universal source of energy in living cells.Less known is that this molecule has a variety of important signaling func-tions:it activates a variety of specific metabotropic(P2Y)and ionotropic(P2X)receptors in neuronal and non-neu-ronal cell membranes.So,a wide variety of signaling func-tions well fits the ubiquitous presence of ATP in the tissues.Even more ubiquitous are protons.Apart from the unspe-cific interaction of protons with any protein,many physi-ological processes are affected by protons acting on specific ionotropic receptors--acid-sensing ion channels(ASICs).Both protons(acidification)and ATP are locally elevated in various pathological states.Using these fundamentally important molecules as agonists,ASICs and P2X receptors signal a variety of major brain pathologies.Here we briefly outline the physiological roles of ASICs and P2X receptors,focusing on the brain pathologies involving these receptors.

PXR基因单核苷酸多态性与2型糖尿病患病风险的关系

目的探讨孕烷X受体(PXR)基因单核苷酸多态性(SNP)与2型糖尿病(T2DM)患病风险的关系。方法选择T2DM患者285例(观察组)、同期体检健康的志愿者230例(对照组),采集所有研究对象空腹外周静脉血,提取基因组DNA,然后对PXR基因rs1523127、rs3814055、rs6785049位点进行测序和基因分型;采用ELISA法检测血清PXR、葡萄糖转运体2(GLUT2)、葡萄糖激酶(GCK)。比较两组PXR基因rs1523127、rs3814055、rs6785049位点基因型及等位基因频率,以及血清PXR、GLUT2、GCK水平。分析PXR基因SNP与T2DM患病风险的关系。结果经Hardy-Weinberg遗传平衡检验,两组PXR基因不同位点基因型、等位基因频率均符合遗传平衡定律。两组PXR基因rs1523127、rs6785049位点基因型及等位基因频率比较差异均无统计学意义(P均>0.05)。观察组PXR基因rs3814055位点CT/TT基因型及T等位基因频率均高于对照组(P均<0.05),携带CT、TT基因型者罹患T2DM的优势比(OR)分别为携带CC基因型者的1.591、2.398倍,携带T等位基因者罹患T2DM的OR为携带C等位基因者的1.638倍。观察组血清PXR水平高于对照组,血清GLUT2、GCK水平低于对照组(P均<0.05)。T2DM患者PXR基因rs3814055位点CT/TT基因型者血清PXR水平高于CC基因型者,血清GLUT2、GCK水平低于CC基因型者(P均<0.05)。结论PXR基因rs3814055位点C等位基因突变为T等位基因能够增加其转录活性,抑制血清GLUT2、GCK水平,使其糖耐量受损,进而增加T2DM的患病风险。

TET2重塑CXCR4 DNA甲基化对急性心肌梗死小鼠心肌组织自噬、炎症反应及凋亡的影响

目的:探究急性心肌梗死(AMI)过程中内皮细胞tet甲基胞嘧啶双加氧酶2(TET2)对趋化因子受体4(CXCR4)DNA甲基化的影响以及对AMI小鼠心肌组织自噬、炎症反应及组织细胞凋亡的影响机制,为临床探究AMI发展的分子机制提供理论依据。方法:8周龄雄性C57/BL6小鼠50只,制备AMI模型,尾部注射TET2、CXCR4过表达质粒;蛋白免疫印迹(Western Blot)法检测心肌组织TET2、CXCR4、微管相关蛋白3(LC3)、P62、B细胞淋巴瘤/白血病-2基因(Bcl-2)关联X蛋白(Bax)、半胱氨酸蛋白酶3(Caspase-3)、Bcl-2表达;甲基化检测CXCR4 DNA甲基化水平;酶联免疫吸附法(ELISA)检测心肌组织内炎性因子白细胞介素-6(IL-6)、肿瘤坏死因子-α(TNF-α)、白细胞介素-1β(IL-1β)水平;原位末端转移酶标记技术(TUNEL)检测各组心肌组织细胞凋亡指数。结果:与假手术组比较,模型组心肌组织内TET2、CXCR4均表达上调,TET2、CXCR4均在心肌组织内过表达,TET2过表达促进CXCR4表达,差异有统计学意义(P<0.05);与模型组比较,TET2 mimic组CXCR4启动子区域DNA甲基化程度降低,CXCR4蛋白表达升高,差异有统计学意义(P<0.05);与假手术组比较,模型组小鼠心肌组织自噬蛋白LC3、抑制细胞凋亡蛋白Bcl-2表达下调,炎性因子IL-6、TNF-α、IL-1β水平、自噬蛋白P62、促细胞凋亡蛋白Bax、cleaved Caspase-3表达上调,差异有统计学意义(P<0.05);TET2、CXCR4过表达进一步下调LC3、Bcl-2蛋白表达,上调炎性因子IL-6、TNF-α、IL-1β水平,P62、Bax、cleaved Caspase-3蛋白表达;TET2、CXCR4二者联合体现出最低LC3、Bcl-2蛋白表达,最高炎性因子IL-6、TNF-α、IL-1β水平以及P62、Bax、cleaved Caspase-3蛋白表达,差异有统计学意义(P<0.05)。结论:AMI发展中,TET2通过降低CXCR4 DNA甲基化,促进CXCR4基因表达,进而抑制AMI小鼠心肌组织自噬,上调炎症反应及细胞凋亡程度,促进疾病发展。

连翘叶提取物通过PXR/CYP17A1影响孕马血清促性腺激素在肝脏的代谢

【目的】研究连翘叶提取物(Forsythia suspensa leaves extract,FSLE)对孕马血清促性腺激素(pregnant mare serum gonadotropin,PMSG)在肝脏中代谢的影响,改善在畜牧生产中因PMSG代谢缓慢而造成的氧化应激。【方法】采用半仿生酶醇法提取连翘叶有效成分,给予昆明雌鼠不同含量的FSLE进行动物体内试验;收集小鼠血清,进行酶联免疫吸附试验,检测各组小鼠血清中PMSG的质量浓度;采集小鼠肝脏组织,检测氧化应激指标谷胱甘肽、超氧化物歧化酶、丙二醛和过氧化氢的水平;采用Western-blot检测小鼠肝脏组织孕烷X受体(pregnane X receptor,PXR)和细胞色素酶P45017A1(cytochrome P45017A1,CYP17A1)蛋白的表达水平。【结果】FSLE可显著降低小鼠血清中PMSG的质量浓度,且可以减缓PMSG代谢引起的氧化应激。Western-blot结果显示:FSLE可显著下调小鼠肝组织中PXR和CYP17A1蛋白的表达。【结论】连翘叶提取物可能是通过下调肝脏中PXR和CYP17A1的表达减缓PMSG代谢引起的氧化应激。

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。

类视黄醇X受体对缺氧/复氧诱导的大鼠Ⅱ型肺泡上皮细胞氧化应激反应的调控作用

目的:探讨类视黄醇X受体(RXR)在缺氧/复氧(HR)诱导的大鼠Ⅱ型肺泡上皮细胞(AECⅡ)氧化应激反应中的调控作用。方法:随机将细胞实验分成5组:对照(C)组、HR组、HR+溶剂二甲基亚砜(DMSO)组(HD组)、HR+RXR激动剂9-顺式维甲酸(9-RA)组(RA组)和HR+RXR抑制剂HX531组(HX组)。采用CCK-8法检测各组细胞活力;免疫荧光法进行AECⅡ特异性指标表面活性物质蛋白A(SP-A)的鉴定和RXRα表达的观察;试剂盒检测细胞内超氧化物歧化酶(SOD)活性和丙二醛(MDA)含量;透射电镜观察细胞内超微结构的变化;Western blot检测核因子E2相关因子2(Nrf2)蛋白水平;RT-PCR检测Nrf2的mRNA表达水平。结果:与C组相比,HR、HD、RA和HX组细胞活力均显著降低(P<0.05),SOD活性显著下降(P<0.05),MDA含量显著增高(P<0.05),Nrf2的mRNA和蛋白表达水平显著降低(P<0.05或P<0.01),RXRα的免疫荧光表达显著增加(P<0.01);与HR和HX组相比,RA组细胞活力增加(P<0.05),SOD活性上升(P<0.05),MDA含量下降(P<0.05),Nrf2的mRNA和蛋白表达水平升高(P<0.01),RXRα的免疫荧光表达显著增加(P<0.01)。结论:HR可加剧大鼠AECⅡ的氧化应激反应,RXR激动剂干预后可通过抑制氧化应激反应减轻HR引起的大鼠AECⅡ损伤。

基于FXR-FGF19通路研究益生菌对胆总管结石患者胆汁酸代谢的影响

背景:胆总管结石在取石术后有较高的复发率。近年研究表明肠道微生态失衡与胆固醇结石的形成有关。目的:探究益生菌干预对胆固醇结石高危人群血清脂多糖(LPS)以及胆汁酸代谢指标的影响。方法:选取2021年6月—2023年6月在石河子大学第一附属医院行ERCP取石术的胆总管结石患者60例,收集胆汁和粪便样本行细菌培养。将患者随机分为对照组和益生菌干预组,对照组取石术后予常规支持治疗,干预组在常规治疗的基础上服用双歧杆菌三联活菌肠溶胶囊420 mg,每日2次,连续6个月。检测治疗前后革兰阴性菌细胞壁成分LPS、胆汁酸代谢关键分子成纤维细胞生长因子19(FGF19)和胆汁酸合成限速酶胆固醇7α-羟化酶(CYP7A1)血清水平的变化。结果:胆总管结石患者胆汁、粪便细菌培养显示主要致病菌为大肠埃希菌和肺炎克雷伯菌。ERCP取石术后6个月,患者血清LPS、FGF19水平明显降低,CYP7A1水平明显升高(P均<0.05),益生菌干预组数据变化较对照组更为显著(P均<0.05)。结论:口服益生菌制剂可降低胆固醇结石高危人群的血清LPS水平,同时调节胆汁酸经肠肝循环代谢的经典通路法尼酯X受体(FXR)-FGF19通路,从而减少胆汁中的胆固醇过饱和,降低胆固醇结石的形成概率。