酰基辅酶A胆固醇酰基转移酶-1与动脉粥样硬化

酰基辅酶A胆固醇酰基转移酶目前认为是细胞内唯一合成胆固醇酯的酶,维持着细胞以及生物体胆固醇代谢的平衡,而酰基辅酶A胆固醇酰基转移酶-1在动脉粥样硬化的发生、发展过程中发挥着至关重要的作用。自从酰基辅酶A胆固醇酰基转移酶的cDNA在1993年首次被克隆之后,许多学者对酰基辅酶A胆固醇酰基转移酶-1进行了大量的研究,现就近年来酰基辅酶A胆固醇酰基转移酶-1与动脉粥样硬化关系的研究予以综述。     

胆固醇诱导未折叠蛋白反应及其调节酰基辅酶A胆固醇酰基转移酶2基因的表达

目的探讨胆固醇对肝细胞和小肠粘膜上皮细胞中未折叠蛋白反应及其调节酰基辅酶A胆固醇酰基转移酶2基因表达的影响。方法以不同浓度(10mg/L和20mg/L)的游离胆固醇和氧化胆固醇温育肝癌细胞系HepG2细胞和小肠粘膜上皮细胞系Caco2细胞,应用半定量逆转录聚合酶链反应法检测两种细胞中X盒结合蛋白1和酰基辅酶A胆固醇酰基转移酶2mRNA的表达水平。结果随着游离胆固醇和氧化胆固醇温育浓度的升高,HepG2细胞和Caco2细胞中的X盒结合蛋白1和酰基辅酶A胆固醇酰基转移酶2mRNA表达均上调,呈现浓度依赖性。结论胆固醇和氧化胆固醇均可诱导未折叠蛋白反应中标记分子X盒结合蛋白1的表达,并上调酰基辅酶A胆固醇酰基转移酶2的表达,提示酰基辅酶A胆固醇酰基转移酶2的表达可能受未折叠蛋白反应的调控;鉴于酰基辅酶A胆固醇酰基转移酶2在胆固醇吸收的酯化过程中具有重要作用,未折叠蛋白反应可能在胆固醇吸收调控中具有重要意义。     

乙酰化低密度脂蛋白促进胆固醇酰基转移酶活性升高的机制研究

目的 :研究乙酰化低密度脂蛋白 (Ac LDL)对人THP 1单核细胞 (MC)分化的巨噬细胞 (MP)酰基辅酶A、胆固醇酰基转移酶 1(ACAT 1)活性的影响及其机制。方法 :体外培养人THP 1单核细胞系 ,由佛波酯 (PMA)作用使其分化为MP ,后者再由乙酰化低密度脂蛋白Ac LDL进行脂质负荷转变为泡沫细胞。该过程中以放射性同位素标记底物法检测ACAT 1酶活性的变化 ,并用Westernblot法检测ACAT 1酶蛋白的表达及RT PCR法检测A CAT 1mRNA的水平。结果 :在MC分化为MP的过程中ACAT 1酶活性升高了 2倍 ,差异有统计学意义 (P <0 .0 5 ) ,酶蛋白及mRNA水平呈现类似变化趋势 ;Ac LDL作用于巨噬细胞 ,使ACAT1酶活性、酶蛋白及mRNA进一步升高 ,差异有统计学意义 (P <0 .0 5 )。结论 :MC分化为MP的过程中ACAT 1表达上调 ,使ACAT 1活性增强 ,而Ac LDL可进一步促进ACAT 1基因表达增加 ,升高ACAT 1活性。     

酰基辅酶A胆固醇酰基转移酶1基因过表达对泡沫细胞形成的影响

目的研究在三种不同细胞中过表达酰基辅酶A胆固醇酰基转移酶1基因对泡沫细胞形成的影响。方法构建携带酰基辅酶A胆固醇酰基转移酶1全长cDNA的pCDNA3.1质粒载体并稳定转染体外培养的人THP-1单核细胞、小鼠RAW264.7单核巨噬细胞和人胚肾293上皮细胞,以油红O染色法检测在乙酰化低密度脂蛋白作用下转染前后三种细胞形成泡沫细胞的情况。结果在相同的脂质负荷条件下,转染酰基辅酶A胆固醇酰基转移酶1基因的THP-1单核细胞和RAW264.7巨噬细胞同未转染的细胞相比泡沫细胞的形成数量增加,而人胚肾293上皮细胞无论是否转染酰基辅酶A胆固醇酰基转移酶1基因均不易形成泡沫细胞。结论单核巨噬细胞中过表达酰基辅酶A胆固醇酰基转移酶1基因可促进泡沫细胞的形成。     

养肝利胆颗粒对胆固醇结石小鼠肝脏基因表达的影响

[目的]探讨养肝利胆颗粒对胆固醇结石C57小鼠肝脏基因表达的影响。[方法]38只C57BL／6雌性小鼠随机分为正常对照组（n=10）、模型组（n=15）和养肝利胆颗粒组（n=13）。其中后2组小鼠采用高脂饮食诱发法建立胆固醇结石模型。造模同时,养肝利胆颗粒组小鼠予养肝利胆颗粒2．1g·kg^-1·d^-1灌胃治疗。8周后观察各组小鼠的成石率,并用OligO GE Array芯片检测肝脏基因表达的改变。[结果]正常对照组成石率为0;模型组成石率为73．33％;养肝利胆颗粒组成石率为30．77％,明显低于模型组（P〈0．01）。模型组较正常对照组上调基因34条,养肝利胆颗粒组较模型组下调基因12条。[结论]养肝利胆颗粒可以通过调控胆固醇脂质代谢、炎症应答等相关基因表达来发挥防治胆石症的作用。     

肿瘤坏死因子α对乙酰辅酶A:胆固醇酰基转移酶1基因表达的影响

目的研究泡沫细胞形成过程中肿瘤坏死因子-α（TNF-α）对乙酰辅酶A：胆固醇酰基转移酶1（ACAT1）基因的影响。方法体外培养人THP-1单核细胞系,由佛波酯作用使其分化为巨噬细胞,再由乙酰化低密度脂蛋白作用转变为泡沫细胞。TNF-α分别作用于上述三种细胞24h,用Western blot法检测ACAT1蛋白表达,RT-PCR法检测ACAT1 mRNA水平。结果在单核细胞分化为巨噬细胞及转变为泡沫细胞的过程中,ACAT1蛋白及mRNA均增加（P均〈0．05）;TNF-α可上调三种细胞ACAT1蛋白表达及mRNA水平（P均〈0．05）。结论单核细胞分化为巨噬细胞及转变为泡沫细胞的过程中,ACAT1基因表达明显增加,TNF-α可明显促进ACAT1基因表达。     

高胆固醇饮食对小鼠肝脏内皮脂酶mRNA表达的影响

目的内皮脂酶（endothelial lipase，EL）是新近发现的一种脂肪酶，它与肝脂肪酶（HL）、脂蛋白脂肪酶同属于甘油三酯脂肪酶基因家族，参与高密度脂蛋白（HDL）的代谢。本研究旨在观察高胆固醇饮食对小鼠肝脏EL mRNA表达的影响，并同时检测小鼠血脂水平的改变，研究EL mRNA表达水平与血脂的关系。     

脂肪分化相关蛋白促进RAW 264.7细胞内酰基辅酶A:胆固醇酰基转移酶1高表达

目的 观察高表达脂肪分化相关蛋白细胞内酰基辅酶A∶胆固醇酰基转移酶1表达的变化,阐明脂肪分化相关蛋白促进细胞内脂质蓄积的机制.方法 构建的pQCXIP-HA-Adi逆转录病毒载体转染PA317包装细胞,获得pQCXIP-HA-Adi逆转录病毒.用病毒感染RAW 264.7细胞, Puromycin筛选后获得稳定高表达脂肪分化相关蛋白的RAW264.7细胞株.应用逆转录聚合酶链反应和免疫印迹法检测经感染后细胞内脂肪分化相关蛋白和酰基辅酶A∶胆固醇酰基转移酶1的表达.并应用阿托伐他汀处理高表达脂肪分化相关蛋白的RAW 264.7细胞,观察酰基辅酶A∶胆固醇酰基转移酶1表达的改变.结果 用pQCXIP-HA-Adi逆转录病毒感染RAW 264.7细胞后,脂肪分化相关蛋白和酰基辅酶A∶胆固醇酰基转移酶1 mRNA和蛋白表达明显升高,而对照组表达无明显变化.加入阿托伐他汀后,即在去除底物对酰基辅酶A∶胆固醇酰基转移酶1表达影响的情况下,高表达脂肪分化相关蛋白细胞内酰基辅酶A∶胆固醇酰基转移酶1表达仍升高.结论 高表达脂肪分化相关蛋白可明显上调RAW 264.7细胞酰基辅酶A∶胆固醇酰基转移酶1的表达.     

胆囊胆固醇结石易患鼠和免患鼠肝胆脂质代谢和分泌的特征

关于胆囊胆固醇结石的确切病因目前尚不清楚 ,我们选用同系纯合的胆囊结石易患鼠和免患鼠为模型 ,研究其肝胆系脂质代谢、分泌特征与胆囊胆固醇结石形成的关系。一、材料和方法1.动物和动物餐 :年龄 6周的同系纯合雄性ＡＫＲ和Ｃ5 7Ｌ鼠由美国Ｊａｃｋｓｏｎ实验室提供 ,Ｃ5 7Ｌ鼠含有结石等位基因系胆囊胆固醇结石易患鼠 ;ＡＫＲ鼠具有抗结石形成等位基因 ,为胆囊结石免患鼠。实验动物在恒温 (2 2± 1)°Ｃ、光控 (光线从早晨 6时至下午 6时 )的动物房中 ,用含 0 .0 2 %胆固醇的动物餐饲养。在 10～ 12周时Ｃ5 7Ｌ和ＡＫＲ鼠改用结石餐 (…     

PPAR-γ对单核/巨噬细胞酰基辅酶A:胆固醇酰基转移酶-1表达效应的研究

目的　研究配体罗格列酮活化的过氧化体增殖物激活型受体 γ(PPAR γ)对单核 /巨噬细胞转分化过程中酰基辅酶A :胆固醇酰基转移酶 1 (Acyl CoA :cholesterolacyltransferases,ACAT 1 )表达效应的影响。 方法　在RPMI1 640培养基中培养人单核细胞 (THP 1 ) ,加入佛波酯(PMA)培养 48h,细胞贴壁呈巨噬细胞样分化。运用免疫细胞化学、逆转录聚合酶链反应、蛋白质免疫印迹等方法 ,观察单核巨噬细胞转分化前后PPAR γ对ACAT 1mRNA和蛋白表达水平的影响。结果　单核巨噬细胞转分化前后ACAT 1表达增加 ,罗格列酮活化的PPAR γ可明显抑制A CAT 1的表达。结论　动脉粥样硬化事件的发生可能与ACAT 1表达增强有关。罗格列酮活化的PPAR γ可能通过抑制ACAT 1表达 ,巨噬细胞摄取脂质降低 ,从而减少泡沫细胞的形成 ,发挥其抗动脉粥样硬化的作用     

胆囊胆固醇结石患者肝脏受体类似物1基因表达差异的研究

目的研究胆囊胆固醇结石患者肝脏受体类似物1(LRH-1)表达,探讨其与胆固醇结石病发病的关系。方法27例胆囊胆固醇结石患者,男6例,女21例,平均年龄52．44岁。14例无胆石症者为对照(肝脏肿瘤2例,胆囊息肉患者12例),男9例,女5例,平均年龄47．50岁。测定胆汁脂类成分和计算胆汁胆固醇饱和指数。实时定量PCR法测定肝脏LRH-1 mRNA的表达量。结果胆石组LRH-1表达14．18±9．37,高于对照组7．86±6．19,(P＜0．05),胆石组胆汁呈胆固醇过饱和(1．17±0．27)。结论本研究提示肝脏LRH-1表达增高与胆囊胆固醇结石病有关。     

胆固醇结石病的发生机制

胆石病是常见病,患病率在10%左右.近期,胆固醇结石病与代谢综合征,肠肝轴脂质代谢异常受到关注.本文论述胆固醇结石发病机制的研究领域中有关胆汁胆固醇的主要来源,肠道吸收胆固醇,胆囊运动的调节,胆固醇的载体以及代谢综合征的进展,并提出胆囊结石病基础研究的若干任务.     

胆固醇结石、胆囊黏膜和胆汁细菌DNA的检测

目的　探讨胆固醇结石中细菌DNA的意义。方法　用半定量PCR和16SrRNA序列分析法检测胆囊黏膜、胆汁和胆石的细菌DNA ,观察围手术期抗生素的使用对检测结果的影响。结果　(1)结石核心、外周、胆汁和胆囊黏膜细菌DNA阳性率分别为79%、82 %、77%和6 4 %。胆石、胆汁和胆囊黏膜间细菌DNA阳性率无相关性。(2 )结石核心、外周、胆汁和胆囊黏膜细菌菌落数对数值(cfu)分别为3.19±2 .0 9、3.2 6±2 .0 5、3.2 3±2 .14和3.2 8±2 .70。结石内外菌落数相关系数为0 .82 2 (P <0 .0 5 )。胆汁和胆囊黏膜菌落数不相关。胆石核心及外周与胆汁和胆囊黏膜菌落数均不相关。(3)术前用与不用抗生素者胆汁、胆囊黏膜、胆石核心和外周的细菌DNA阳性率均差异无显著性。但用抗生素者胆汁菌落数下降,与未用抗生素组比较差异有显著性(P <0 .0 1) ,而胆囊黏膜、胆石核心和外周的菌落数则差异无显著性。(4)胆石、胆汁、胆囊黏膜的细菌DNA序列并不完全相同,胆石核心与外周部位的DNA序列也不相同。结论　胆固醇结石中细菌DNA可能并非胆道环境细菌污染的结果。较之胆汁和胆囊黏膜的细菌DNA ,胆固醇结石中的细菌DNA与结石形成的关系更密切。     

Claudin-3 regulates bile canalicular paracellular barrier and cholesterol gallstone core formation in mice

Background & Aims

Most cholesterol gallstones have a core consisting of inorganic and/or organic calcium salts, although the mechanisms of core formation are poorly understood. We examined whether the paracellular permeability of ions at hepatic tight junctions is involved in the core formation of cholesterol gallstones, with particular interest in the role of phosphate ion, a common food additive and preservative.

同型半胱氨酸及代谢酶基因多态性与脑卒中的相关性研究

目的 进一步确定亚甲基四氢叶酸还原酶(MTHFR)基因C677T、胱硫醚β-合成酶(CBS)基因844ins68、T27796C和甲硫氨酸合成酶(MS)基因A2756G这4种基因突变在脑卒中发病中的意义。方法 选择年龄及性别基本匹配的脑梗死组78例、脑出血组26例、神经系统其他疾病组29例和健康老年组50例，采用酶联免疫分析法测定受检者血浆同型半胱氨酸(Hcy)浓度，并运用多聚酶链反应-限制性内切酶片段长度多态性技术，检测基因表型。结果 脑梗死组和脑出血组血Hcy浓度明显高于神经系统其他疾病组和健康老年组。CBS844ins68及MSA2756G突变频率较国外报道明显低。此外，C677T纯合突变型的Hcy水平均高于野生型和杂合突变型，CBST27796C基因杂合子突变则可能使Hcy水平降低；而4种基因各组之间基因型频率差异无统计学意义。结论 Hcy水平与脑卒中的发生有一定联系。CBS844ins68和MSA2756G突变可能存在种族或地域差异，MTHFRC677T纯合子突变可能是导致血浆总Hcy(tHcy)水平升高的遗传决定簇，而CBST27796C基因杂合子突变可能引起tHcy水平的降低；4种基因突变符合遗传平衡定律。     

Cholangiocyte bile salt transporters in cholesterol gallstone-susceptible and resistant inbred mouse strains

Background and Aim: We investigated the dietary and gender influences on the expression and functionality of cholangiocyte bile salt transporters and development of biliary hyperplasia in cholesterol gallstone‐susceptible C57L/J and resistant AKR/J mice. Methods: C57L and AKR mice were fed chow, a lithogenic diet, or a cholic acid‐containing diet for 14 days. Expression of cholangiocyte bile salt transporter proteins ASBT (SLC10A2), ILBP (FABP6), and MRP3 (ABCC3) were studied by Western blot analysis. Taurocholate uptake studies were performed using microperfusion of isolated bile duct units. The pre‐ and post‐perfusion taurocholate concentrations were analyzed by high performance liquid chromatography. Biliary proliferation in liver sections was scored. Results: The lithogenic diet induced ductular proliferation in C57L mice. On chow, SLC10A2 and ABCC3 were overexpressed in male and female C57L compared to AKR mice. A lithogenic diet reduced the expressions of FABP6 in both male and female C57L mice, SLC10A2 in female C57L mice, and ABCC3 in male C57L mice. These alterations in transporter expressions were not associated with changes in taurocholate uptake. The lithogenic diet induced biliary hyperplasia and reduced bile salt transporter expressions in C57L mice. Conclusions: Although bile salt uptake was not increased in the bile duct unit, we speculate that the biliary hyperplasia on the lithogenic diet may lead to an increase in intrahepatic bile salt recycling during cholesterol cholelithogenesis.     

Association of caveolin-3 and cholecystokinin A receptor with cholesterol gallstone disease in mice

AIM: To investigate the role of caveolin-3 (CAV3) and cholecystokinin A receptor (CCKAR) in cholesterol gallstone disease (CGD).METHODS: To establish a mouse model of CGD, male C57BL/6 mice were fed with a lithogenic diet containing 1.0% cholic acid, 1.25% cholesterol and 15% fat; a similar control group was given a normal diet. The fresh liver weights and liver-to-body weight ratio were compared between the two groups after one month. Serum lipid profile and bile composition were determined with an autoanalyzer. The Cav3 and Cckar mRNA and CAV3 and CCKAR protein levels in the liver and gallbladder were determined via real-time polymerase chain reaction and Western blot, respectively.RESULTS: Establishment of the mouse CGD model was verified by the presence of cholesterol gallstones in mice fed the lithogenic diet. Compared with mice maintained on a normal diet, those fed the lithogenic diet had significantly higher mean liver-to-body weight ratio (0.067 ± 0.007 vs 0.039 ± 0.007, P < 0.01), serum total cholesterol (4.22 ± 0.46 mmol/L vs 2.21 ± 0.11 mmol/L, P < 0.001), bile total cholesterol (1.33 ± 0.33 mmol/L vs 0.21 ± 0.11 mmol/L, P < 0.001), and bile phospholipid concentrations (3.55 ± 1.40 mmol/L vs 1.55 ± 0.63 mmol/L, P = 0.04), but lower total bile acid concentrations (726.48 ± 51.83 μmol/L vs 839.83 ± 23.74 μmol/L, P = 0.007). The lithogenic diet was also associated with significantly lower CAV3 in the liver and lower CAV3 and CCKAR in the gallbladder compared with the control mice (all P < 0.05).CONCLUSION: CAV3 and CCKAR may be involved in cholesterol gallstone disease.     

Biliary cholesterol hypersecretion in gallstone-susceptible mice is associated with hepatic up-regulation of the high-density lipoprotein receptor SRBI

Enhanced hepatocellular trafficking of cholesterol to the bile canaliculus and cholesterol hypersecretion appears critical for gallstone formation. Therefore, we studied in more detail the hepatic cholesterol transport pathways in a mouse model of cholesterol gallstone disease. Biliary lipid secretion rates, plasma lipoprotein levels, hepatic expression of lipoprotein receptors, lipid regulatory enzymes, and putative cholesterol transporting proteins were analyzed in gallstone-susceptible C57L/J and gallstone-resistant AKR/J mice, which were fed a lithogenic diet. Biliary cholesterol hypersecretion in C57L mice was associated with decreased plasma high-density lipoprotein (HDL) cholesterol levels and significant hepatic induction of the HDL receptor (SRBI) and cholesteryl ester hydrolase. In response to the lithogenic diet, fatty-acid binding protein of liver (FABPL) was markedly induced in both mouse strains. Caveolin 1 was elevated only in plasma membranes of gallstone-susceptible C57L mice, which also failed to down-regulate cholesterol synthesis. These data suggest a role of the reverse cholesterol transport pathway for genetically determined gallstone susceptibility in the mouse.     

利拉鲁肽对低脂联素血症小鼠胆固醇代谢相关基因的影响

目的 探讨利拉鲁肽(liraglutide)对脂联素基因表达缺陷ApoE基因敲除(ApoE-/-)小鼠胆固醇代谢相关基因的影响.方法 雄性ApoE-/-小鼠36只按随机数字表法随机分为单纯高脂喂养组(HF组,n=10)、空载腺病毒组(GFP组,n=6)、高脂+脂联素RNAi腺病毒组(ADI组,n=10)、利拉鲁肽治疗的高脂+脂联素RNAi腺病毒组(HEA组,n=10).采用扩展胰岛素钳夹术评价其胰岛素敏感性,酶联免疫法测定血浆脂联素水平,实时荧光定量PCR方法 检测肝脏组织胰岛素诱导基因1和2(INSIG1,INSIG2)、固醇调节元件结合蛋白1和2(SREBP-1,SREBP-2)、羟甲基戊二酸单酰辅酶A还原酶(HMGCR)和低密度脂蛋白受体(LDLR)mRNA表达.结果 ADI组血浆总胆固醇、甘油三酯、低密度脂蛋白胆固醇、空腹胰岛素和游离脂肪酸水平较其他3组显著升高(P＜0.01);而高密度脂蛋白胆固醇水平则显著降低(P＜0.05).ADI组血浆脂联素水平显著低于HEA、HF和GF组(P＜0.01).ADI组肝组织INSIG2和LDLR mRNA表达水平较其他3组显著降低(P＜0.01或P＜0.05);HEA组肝组织HMGCR 和SREBP-2 mRNA表达水平较其他3组明显升高(P＜0.01或P＜0.05);ADI、HF和GFP组HMGCR和SREBP-2 mRNA表达水平无明显差异.结论 利拉鲁肽可能通过上调脂联素水平调节胆固醇代谢相关基因的表达,从而改善胆固醇代谢紊乱.

Abstract：

Objective To investigate the effects of liraglutide on gene expression related to cholesterol metabolism in ApoE-/-mice with adiponectin deficiency. Methods Thirty six ApoE-/-mice fed with the high-fat diet were subdivided into four groups. One group was given 100 μl(1×109PFU) of adenoviral pAd-U6-GFP(GFP group, n=6). The second group received 100 μl of adenoviral pAd-U6-Acrp30(ADI group, n=10). The third group was given 100 μl of adenoviral pAd-U6-Acrp30 and liraglutide(HEA group, n=10) and the fourth group was given only 100 μl sterile saline(HF group, n=10). Insulin sensitivity and glucose metabolism were assessed by the hyperinsulinemic-euglycemic clamp technique using 3-[3H] glucose as a tracer. Plasma adiponectin level was evaluated using a commercially available ELISA kit. The mRNA expressions of genes involved in cholesterol metabolism were measured by quantitative realtime PCR. Results Fasting blood glucose(FBG), free fatty acids(FFA), total cholesterol, triglyceride, low density lipoprotein cholesterol, adiponectin, and fasting plasma insulin(FINS) in ADI mice were significantly higher than those in the other groups(P＜0.01), while high density lipoprotein cholesterol was significantly lower(P＜0.05). During the clamp, glucose infusion rate(GIR) in ADI group was significantly lower than the other groups(P＜0.01), and hepatic glucose production(HGP) significantly higher in ADI group(P＜0.01). The mRNA expressions of INSIG2 and LDLR in ADI group were significantly down-regulated in HEA group(P＜0.01 or P＜0.05), while HMGCR and SREBP-2 were significantly up-regulated in HEA group(P＜0.01 or P＜0.05). Conclusions Liraglutide regulates a number of genes involved in cholesterol metabolism and ameliorates hypercholesterolemia by elevating plasma adiponectin level.