基质金属蛋白酶及其抑制剂在肝纤维化中的表达变化

目的 观察肝纤维化形成过程中基质金属蛋白酶MMP-1及其抑制剂TIMP-1的表达变化,从细胞外基质降解代谢的角度研究四氯化碳(CCl4)中毒性肝纤维化发生的机制.方法 雄性Wistar大鼠20只,分为正常组和肝纤维化模型组.肝纤维化组采用CCl4、饮酒、高脂低蛋白饮食等复合病因刺激制备肝纤维化动物模型,造模时间为8周.实验结束后测定肝脏指数、血清透明质酸(HA)、谷丙转氨酶(ALT)及尿羟脯氨酸(HYP)排出量,光镜下观察肝组织纤维化程度,并用免疫组化SABC法检测肝组织中Ⅰ、Ⅲ型胶原蛋白及MMP-1、TIMP-1的表达,同时用荧光实时定量PCR(RT-PCR)的方法检测肝组织中MMP-1、TIMP-1 mRNA的表达.结果 与正常对照组比较,肝纤维化模型组大鼠肝脏指数、血清HA及ALT显著增高,尿羟脯氨酸的排出量明显增加,病理组织学检查发现肝组织内纤维结缔组织增生明显,有假小叶形成;免疫组化的结果显示肝组织内Ⅰ、Ⅲ型胶原蛋白、MMP-1及TIMP-1的表达较正常组显著增加.结论 肝组织中MMP-1及TIMP-1的表达变化可能是导致肝纤维化的重要机制之一.     

中药乙肝散逆转肝纤维化过程中肝组织TIMP-1及MMP-2表达变化的实验研究

目的探讨中药乙肝散逆转免疫性肝纤维化过程中肝组织TIMP-1(金属蛋白酶组织抑制因子-1) 及MMP-2(间质金属蛋白酶-2)表达的变化.方法雄性Wistar大鼠尾静脉注射白蛋白建立免疫损伤性肝纤维化模型后,分组加用不同浓度的乙肝散颗粒饲料喂养12周,流式细胞仪定量分析大鼠肝组织TIMP-1和MMP-2基因表达量,观察大鼠肝组织病理、苦味酸-天狼红染色、Ⅳ胶原免疫组化、α-SMA(α平滑肌肌动蛋白)免疫组化、肝匀浆Hyp(羟脯氨酸).结果乙肝散应用组肝组织TIMP-1表达量较模型对照组明显降低(P<0.01),MMP-2变化无统计学差异;同时肝组织Ⅰ胶原、Ⅲ胶原、Ⅳ胶原水平和Hyp含量明显降低(P<0.01或P<0.05).结论中药乙肝散在逆转肝纤维化过程中对抑制肝组织TIMP-1基因表达具有一定作用,TIMP-1在肝纤维化的逆转中起重要作用.     

肝组织TGF-β1、TIMP-1及MMP-2表达与纤维化关系的实验研究

目的探讨免疫性肝纤维化肝组织TGF-β1、TIMP-1及MMP-2表达与肝纤维化间的关系.方法 24只雄性Wistar大鼠尾静脉注射白蛋白建立实验性免疫性肝纤维化模型,检测血清HA、ALT、AST、ALB,流式细胞仪定量分析肝组织TGF-β1、TIMP-1、MMP-2和α-SMA基因表达量,观察大鼠肝组织病理、肝组织Pollak三重染色和Gomori银染色、苦味酸-天狼红染色、Ⅳ型胶原免疫组化、α-SMA免疫组化、肝匀浆Hyp测定.结果随着肝纤维化程度的加重血清HA、ALT、AST、肝组织匀浆Hyp的浓度和TGF-β1、TIMP-1及α-SMA基因表达量均增加, MMP-2于肝纤维化早期明显升高,晚期明显降低.结论实验性肝纤维化过程中TGF-β1、TIMP-1促进肝纤维化的进展,MMP-2抑制其进展.     

大鼠肝纤维化组织中TGF-β1的研究

目的 观察转化生长因子-β1(transforming growth factor-β1,TGF-β1)在大鼠肝纤维化组织中的动态表达,探讨TGF-β1在肝纤维化中的意义.方法 采用腹腔内注射二甲基亚硝胺(DMN)构建大鼠肝纤维化模型,造模后4天、1周、2周、4周、6周、8周分别检测血清ALT、AST、ALB的变化,同时取肝组织用半定量RT-PCR方法检测TGF-β1 mRNA的表达.采用HE染色及Masson三色染色,光学显微镜下观察肝组织损伤情况.采用单因素方差分析进行多组均数间的比较.结果 肝纤维化模型组血清ALT、AST明显升高,ALB明显下降.TGF-β1 mRNA在对照组大鼠和肝纤维化模型组大鼠肝组织中均有表达.与对照组相比,肝纤维化模型组4天～1周时,TGF-β1 mRNA表达差异无统计学意义(P均＞0.05).2～4周较对照组显著升高(P均＜0.05),4周时达高峰.6～8周较4周时显著下降(P均＜0.05),但仍显著高于对照组(P均＜0.05).8周较6周时下降,差异无统计学意义(P＞0.05).TGF-β1 mRNA表达与肝纤维化病程呈正相关(P＜0.01).结论 TGF-β1 mRNA在正常SD大鼠肝脏中有表达,在肝纤维化大鼠肝组织中表达增加,与大鼠肝脏病理分期正相关.     

基质金属蛋白酶及其抑制因子与扩张型心肌病的关系

目的研究基质金属蛋白酶-2(MMP-2)及金属蛋白酶组织抑制因子(TIMP-1)在扩张型心肌病(DCM)中的变化,探讨血管紧张素转换酶抑制剂(ACEI)对心肌纤维化的影响及其调控机制。方法雄性SD大鼠腹腔注射阿霉素(2 mg/kg,每周1次,连续8周)建立扩张型心肌病模型。将达到DCM诊断标准的大鼠分3组:①H组(卡托普利高剂量干预组,50mg/Kg.d);②L组(卡托普利低剂量干预组,25mg/Kg.d);③C组(DCM对照组)。HE染色和苦味酸天狼星红染色观察各组大鼠心肌细胞和间质胶原变化,RT-PCR法检测心肌MMP-2及TIMP-1的表达。结果与正常对照组比较,DCM组心肌细胞坏死明显、胶原纤维和胶原容积分数增加(P<0.05);而H组和L组的胶原纤维较C组减少(P<0.05)。DCM组心肌MMP-2 mRNA表达较正常对照组显著增加(P<0.01),H组和L组较C组降低(P<0.05)。DCM组TIMP-1mRNA的表达较正常对照组降低(P<0.05),H组较C组有所增加(P<0.05)。结论 MMP-2及TIMP-1与心肌细胞外基质的重塑密切相关,ACEI有降解MMP-2的作用,可以减轻心肌间质的...     

牛磺酸上调基因1(TUG1)对肝纤维化的作用及其机制*

目的:探讨牛磺酸上调基因1(TUG1)在肝纤维化中的作用机制。方法:按照文献建立TGF-β1(5 ng/ml)刺激的活化肝星状细胞模型和经典的1%DMN(1 ml/kg/d)致大鼠肝纤维化模型,将肝纤维化大鼠和活化肝星状细胞(HSC)均分为模型对照组、阴性对照组(沉默TUG1阴性对照)、siRNA干扰组(TUG1基因沉默组)。实验结束后利用苏木精-伊红(HE)染色检测大鼠肝脏组织病理变化;采用逆转录-聚合酶链反应(RT-PCR)法、蛋白免疫印记(Western blot)分别测定大鼠肝组织及活化肝星状细胞中α-平滑肌肌动蛋白(α-SMA)、TUG1、I型胶原蛋白(collagenI)、基质金属蛋白酶-2(MMP-2)、金属蛋白酶组织抑制因子(TIMP-1)、Smad2、Smad3表达水平。结果:肝组织病理学检查显示,沉默TUG1能够明显缓解肝脏纤维化病理改变,Western blot结果显示,沉默TUG1能够显著降低大鼠肝组织和活化肝星状细胞中TUG1、α-SMA、collagenI、MMP-2、TIMP-1、Smad2、Smad3基因与蛋白表达水平(P＜0.05)。与模型对照组相比,阴性对照组的TUG1、α-SMA的蛋白与基因水平明显升高(P＜0.05)。与模型对照组和阴性对照组相比,siRNA干扰组中TUG1, α-SMA, collagenI, MMP-2, TIMP-1, Smad2 and Smad3的蛋白和基因水平显著降低(P＜0.05),而在模型对照组和阴性对照组中TUG1, α-SMA, collagenI, MMP-2, TIMP-1, Smad2 and Smad3的蛋白和基因表达水平之间差异无显著性。结论:TUG1在肝纤维化组织和活化的肝星状细胞中显著上调,沉默TUG1可能通过抑制转化生长因子-β1(TGF-β1)/Smad信号通路改善1%DMN致大鼠肝纤维化病理损伤,降低活化肝星状细胞中纤维化相关蛋白水平,发挥抗肝纤维化的作用。     

两种不同病毒载体携带靶向大鼠金属蛋白酶组织抑制因子（TIMP）-1小干扰RNA抗肝纤维化作用的比较

目的观察以腺相关病毒（AAV）及慢病毒（Lentivirus）为载体含有针对大鼠金属蛋白酶组织抑制因子（TIMP）-1具有较强抑制作用的小干扰RNA（siRNA）对四氯化碳（CCI。）诱导的大鼠肝纤维化模型的干预作用。方法挑选针对大鼠TIMP-1基因具有较强抑制作用的siRNA序列,在体外构建为短发夹表达载体后,将其包装为重组AAV／siRNA-TIMP-I和Lenti／siRNA-TIMP-I,同时包装对照病毒AAV／EGFP和Lenti／EGFP。将Wistar大鼠分为对照组、CCl。模型组、AAV／EGFP组、Lenti／EGFP组、AAV／siRNA-TIMP-I和Lenti／siRNA-TIMP-1组,观察CCl。造模4周后,经H＆E及Masson染色评价各组动物的肝纤维化状况,经荧光定量RCR及Westernblot方法检测TIMP-1的表达抑制情况。结果H＆E及Masson染色证实,与对照组相比,CCI．模型组、AAV／EGFP组、Lenti／EGFP组肝脏胶原纤维明显增加,纤维化评分多为34级,同时肝脏TIMP-1的转录与蛋白表达水平均明显上升;而AAV／siRNA-TIMP-1和Lenti／siRNA-TIMP-l组肝纤维化程度明显减轻,纤维化评分多为2-3级,伴随肝脏TIMP-1的转录与蛋白表达水平均显著抑制。AAV／siRNA-TIMP-l和Lenti／siRNA-TIMP-I组在组织学表现及TIMP-1基因的转录与表达水平上无统计学差异。结论AAV／siRNA-TIMP-I和Lenti／siRNA-TIMP-1均可有效抑制大鼠肝脏TIMP-1基因表达,进而发挥抗肝纤维化作用。     

急性肺损伤大鼠肺组织基质金属蛋白酶2及其抑制因子蛋白和mRNA的表达

目的探讨内毒素致急性肺损伤（ALI）大鼠肺组织核转录因子-κB（NF-κB）、基质金属蛋白酶2（MMP-2）及其抑制因子（TIMP-2）蛋白和mRNA表达的变化。方法 20只雄性Wistar大鼠随机分为2组：对照组、LPS模型组,每组再分为4 h和8 h两个亚组。尾静脉注射脂多糖（LPS）（10 mg/kg）建立大鼠急性肺损伤模型。检测血白细胞计数、支气管肺泡灌洗液（BALF）蛋白含量,采用免疫组化ABC法和实时荧光定量PCR分别测定肺组织NF-κB、MMP-2、TIMP-2蛋白及其mRNA的表达,并观察肺组织病理变化。结果与对照组相比,模型组4 h和8 h时大鼠肺组织中的NF-κB、MMP-2蛋白染色阳性面积率及其mRNA表达均显著增高（P〈0.01）、TIMP-2蛋白染色阳性面积率及其mRNA表达均明显降低（P〈0.05或P〈0.01）。病理学观察显示,模型组大鼠肺组织出现出血及坏死。结论内毒素致急性肺损伤的发病机制可能与NF-κB、MMP-2蛋白及其mRNA表达升高、TIMP-2蛋白及其mRNA表达降低有关。     

肝纤维化过程中Toll样受体4在肝脏的表达分布及意义

目的动态观察大鼠肝纤维化过程中Toll样受体4（Toll-like receptor4,TLR4）蛋白在肝脏的表达,探讨TLR4与肝纤维化发生发展的关系。方法以四氯化碳皮下注射复制大鼠肝纤维化模型,设立正常对照组和模型1周组、2周组、4周组、6周组。常规HE染色和天狼猩红胶原染色观察肝脏病变;检测肝组织羟脯氨酸和血浆内毒素含量;免疫组化和Western blot检测TLR4在肝组织中的表达,检测α-SMA观察活化的肝星状细胞（HSCs）。结果与正常对照组比较,CCl4作用2周时,肝组织羟脯氨酸含量开始明显增多（P〈0.01）;模型组各组血浆内毒素含量呈梯度上升（P〈0.01）,且与肝组织羟脯氨酸含量呈显著正相关关系（P〈0.01）;CCl4作用1周后肝组织TLR4的表达即明显增强（P〈0.01）,4周时和6周时有所下降（与2周组相比,P〈0.05）,但仍高于正常对照组（P〈0.01）。TLR4阳性细胞包括枯否细胞、活化的HSCs及少量的肝细胞和内皮细胞。结论内毒素及其受体TLR4的改变可能在肝纤维化中起重要作用。     

小干扰RNA沉默瘦素揭示了瘦素在大鼠肝纤维化中的作用

目的观察靶向瘦素(leptin)小干扰RNA(interference,siRNA)真核细胞表达质粒对大鼠肝纤维化的影响。方法采用已构建的重组Leptin-siRNA真核细胞表达质粒,用脂质体包埋法通过腹腔注射将其导入大鼠肝纤维化模型体内。通过HE染色观察肝脏病理形态学变化;Western Blot检测leptin、I型胶原和STAT3蛋白表达变化;半定量RT-PCR检测leptin mRNA表达。结果与正常对照组相比,肝纤维化组(CCl4)和质粒空载体组(CCl4(+)K)肝纤维化程度较重,纤维化评分多为Ⅳ级(P0.01),同时肝脏leptin、I型胶原和STAT3含量明显上升(P0.05);而与肝纤维化组(CCl4)和质粒空载体组(CCl4(+)K)比,leptin-siRNA质粒转染组(The CCl4(+)L)肝纤维化程度减轻,纤维化程度多为Ⅰ-Ⅱ级,肝脏leptin、I型胶原和STAT3表达均显著抑制(P0.05)。正常对照组和leptin-siRNA质粒组(The CCl4(+)L)在组织学及leptin、I型胶原和STAT3基因转录和表达水平无统计学差异(P0.05)。结论 leptin-siRNA表达质粒降低I型胶原和STAT3含量、抑制leptin表达,阻抑肝纤维化;Leptin有望成为肝纤维化基因治疗的新靶位点。     

Chemoenzymatic synthesis of 2-azidoethyl-ganglio-oligosaccharides GD3, GT3, GM2, GD2, GT2, GM1, and GD1a

We have synthesized several ganglio-oligosaccharide structures using glycosyltransferases from Campylobacter jejuni. The enzymes, alpha-(2-->3/8)-sialyltransferase (Cst-II), beta-(1-->4)-N-acetylgalactosaminyltransferase (CgtA), and beta-(1-->3)-galactosyltransferase (CgtB), were produced in large-scale fermentation from Escherichia coli and further characterized based on their acceptor specificities. 2-Azidoethyl-glycosides corresponding to the oligosaccharides of GD3 (alpha-D-Neup5Ac-(2-->8)-alpha-D-Neup5Ac-(2-->3)-beta-D-Galp-(1-->4)-beta-D-Glcp-), GT3 (alpha-D-Neup5Ac-(2-->8)-alpha-D-Neup5Ac-(2-->8)-alpha-D-Neup5Ac-(2-->3)-beta-D-Galp-(1-->4)-beta-D-Glcp-), GM2 (beta-D-GalpNAc-(1-->4)-[alpha-D-Neup5Ac-(2-->3)]-beta-D-Galp-(1-->4)-beta-D-Glcp-), GD2 (beta-D-GalpNAc-(1-->4)-[alpha-D-Neup5Ac-(2-->8)-alpha-D-Neup5Ac-(2-->3)]-beta-D-Galp-(1-->4)-beta-D-Glcp-), GT2 (beta-D-GalpNAc-(1-->4)-[alpha-D-Neup5Ac-(2-->8)-alpha-D-Neup5Ac-(2-->8)-alpha-D-Neup5Ac-(2-->3)]-beta-D-Galp-(1-->4)-beta-D-Glcp-), and GM1 (beta-D-Galp-(1-->3)-beta-D-GalpNAc-(1-->4)-[alpha-D-Neup5Ac-(2-->3)]-beta-D-Galp-(1-->4)-beta-D-Glcp-) were synthesized in high yields (gram-scale). In addition, a mammalian alpha-(2-->3)-sialyltransferase (ST3Gal I) was used to sialylate GM1 and generate GD1a (alpha-D-Neup5Ac-(2-->3)-beta-D-Galp-(1-->3)-beta-D-GalpNAc-(1-->4)-[alpha-D-Neup5Ac-(2-->3)]-beta-D-Galp-(1-->4)-beta-D-Glcp-) oligosaccharide. We also cloned and expressed a rat UDP-N-acetylglucosamine-4'epimerase (GalNAcE) in E. coli AD202 cells for cost saving in situ conversion of less expensive UDP-GlcNAc to UDP-GalNAc.     

Synthesis and physicochemical properties of 2'-deoxy-2',2'-difluoro-beta-D-ribofuranosyl and 2'-deoxy-2',2'-difluoro-alpha-D-ribofuranosyl oligonucleotides

We present procedures for nucleoside and oligonucleotide synthesis, binding affinity (Tm) and structural analysis (CD spectra) of 2'-deoxy-2',2'-difluoro-alpha-D-ribofuranosyl and 2'-deoxy-2',2'-difluoro-beta-D-ribofuranosyl oligothymidylates. Possible reasons for the thermal instability of duplexes formed between these compounds and RNA or DNA targets are discussed.     

Preparation of glycosides of 2-deoxy-2-methylamino-D-mannose, 2-deoxy-2-methylamino-D-glucose,and 2-deoxy-2-methylamino-D-galactose: observations on N-methylation of amides

Benzyl 2-[(benzyloxycarbonyl)methylamino]-2-deoxy-α-D-mannopyranoside (10) and its furanose isomer (9), the derived N-methyloxazolidinones 11 and 6, benzyl 2-[(benzyloxycarbonyl)methylamino]-2-deoxy-β-D-glucofuranoside (15) and methyl 2-deoxy-2-methylacetamido-β-D-galactofuranoside (20), were prepared from appropriate diethyl dithioacetals. They were considered the most suitable starting materials for synthesis of O-methyl-2-deoxy-2-methylamino-hexoses because of their ease of preparation and the presence of suitable blocking groups. Oxazolidinones were prepared from N-benzyloxycarbonyl derivatives of 2-amino-2-deoxy-D-mannose by using methanolic sodium methoxide. Their use in preparation of 2-deoxy-2-methyl-amino derivatives is discussed. The Kuhn reagent was used in these syntheses for N-methylating amides. However, certain amides containing comparatively bulky substituents in the vicinity of the NH group are resistant to methylation.     

Comparison of ERLIC-TiO2, HILIC-TiO2, and SCX-TiO2 for global phosphoproteomics approaches

Reversible phosphorylations play a critical role in most biological pathways. Hence, in signaling studies great effort has been put into identification of a maximum number of phosphosites per experiment. Mass spectrometry (MS)-based phosphoproteomics approaches have been proven to be an ideal analytical method for mapping of phosphosites. However, because of sample complexity, fractionation of phosphopeptides prior to MS analysis is a crucial step. In the current study, we compare the chromatographic strategies electrostatic repulsion-hydrophilic interaction chromatography (ERLIC), hydrophilic interaction liquid chromatography (HILIC), and strong cation exchange chromatography (SCX) for their fractionation behavior of phosphopeptides. In addition, we investigate the use of repetitive TiO(2)-based enrichment steps for a maximum identification of phosphopeptides. On the basis of our results, SCX yields the highest number of identified phosphopeptides, whereas ERLIC is optimal for the identification of multiphosphorylated peptides. Consecutive incubations of fractions and flow-through by TiO(2) beads enrich qualitatively different sets of phosphopeptides, increasing the number of identified phosphopeptides per analysis.     

Effect of prostaglandins A1, A2, B1, B2, E2 and F2 alpha on human umbilical cord vessels

Human umbilical blood vessels have the ability to close spontaneously following delivery at term. It has been suggested that prostaglandins may have a possible physiological role in its closure. This study investigates the effects of 6 naturally occurring prostaglandins (A1, A2, B1, B2, E2, F2a) on the umbilical blood vessels. Umbilical cords were collected from cases of normal spontaneous vaginal deliveries and cesarian section at term. A total of 41 strips of umbilical arteries and 26 strips of umbilical veins from 24 cords were used. A 4-point bioassay method was used to compare the potency of prostaglandins A1, A2, B1 and F2a with PGE2. The effect of Polyphloretin Phosphate (PPP) on prostaglandin-induced contractions was studied on umbilical artery strips from 12 cords. The 6 prostaglandins exerted a stimulant effect on the isolated strips of human umbilical arteries. Prostaglandin B2 was the most potent compound on the umbilical vein, followed by PGA2. PPP in the concentration range of 10 to 40 mcg/ml completely eliminated the responses of PGE2, F2a, A1, A2, and B1. Responses to PGB2 were considerably but not completely abolished. PPP (up to 40 mcg/ml) did not affect contractions induced by 5-hydroxytryptamine, suggesting the presence of discrete receptor sites in the blood vessels for different pharmacologically active compounds. This is the first report of the constrictor effect of PGA and PGB compounds. These naturally occuring prostaglandins with high potencies (compared with other prostaglandins and other vasoactive substances) may play a role in spontaneous closure of umbilical vessels. PGE1, E2, F1 and F2a are found in umbilical blood vessels obtained at term.     

A new synthetic pathway to adenine-2-d, 9-alkyladenine-2-d, adenosine-2-d, and 2'-deoxyadenosine-2-d

Unambiguous assignments of the purine ring protons in the NMR spectra of adenine (Ia) and its 9-substituted derivatives (Ib-f) have been made by comparison with those of the isotopically labeled adenines VIIIa-f. 9-Alkyl-2-deuterioadenines (VIIIb-d), adenosine-2-d (VIIIe), and 2'-deoxyadenosine-2-d (VIIIf) were synthesized from the 9-substituted adenines Ib-f through cyclization of the monocyclic intermediates VIb-f with formic acid-d2 or 1-(formyl-d)-2(1H)-pyridone. Hydrolysis of VIIIe with 0.5 N aq. HCl gave adenine-2-d (VIIIa) in 77% yield.