TLR2 as an essential molecule for protective immunity against Toxoplasma gondii infection

To investigate the role of the Toll-like receptor (TLR) family in host defense against Toxoplasma gondii, we infected TLR2-, TLR4- and MyD88-deficient mice with the avirulent cyst-forming Fukaya strain of T. gondii. All TLR2- and MyD88-deficient mice died within 8 days, whereas all TLR4-deficient and wild-type mice survived after i.p. infection with a high dose of T. gondii. Peritoneal macrophages from T. gondii-infected TLR2- and MyD88-deficient mice did not produce any detectable levels of NO. T. gondii loads in the brain tissues of TLR2- and MyD88-deficient mice were higher than in those of TLR4-deficient and wild-type mice. Furthermore, high levels of IFN-gamma and IL-12 were produced in peritoneal exudate cells (PEC) of TLR4-deficient and wild-type mice after infection, but low levels of cytokines were produced in PEC of TLR2- and MyD88-deficient mice. On the other hand, high levels of IL-4 and IL-10 were produced in PEC of TLR2- and MyD88-deficient mice after infection, but low levels of cytokines were produced in PEC of TLR4-deficient and wild-type mice. The most remarkable histological changes with infiltration of inflammatory cells were observed in lungs of TLR2-deficient mice infected with T. gondii, where severe interstitial pneumonia occurred and abundant T. gondii were found.     

人Nanog基因的克隆及其在COS-7L细胞中的表达

目的 :克隆人Nanog基因 ,构建其真核表达载体 ,并观察其在哺乳动物细胞COS 7L中的表达。方法 :利用HE2 93细胞的人基因组DNA为模板 ,以LA PCR技术 ,扩增Nango的基因 ,定向克隆到带Flag标签的pCMV载体中 ,测序后 ,挑选序列正确的真核表达质粒pFlag Nanog转染COS 7L细胞。用抗Flag标签的抗体 ,进行Westernblot和间接免疫荧光染色法检测Nango蛋白的表达。结果 :从人基因组DNA中克隆到序列正确的Nanog全长编码序列。所构建的Nanog质粒在COS 7L细胞中获得高效表达。结论 :人Nanog基因的克隆、真核表达载体的构建及在COS 7L中的表达均获得成功 ,为进一步研究其功能 ,尤其是探讨其在神经干细胞中的作用奠定了基础。     

具有三层管壁结构组织工程血管支架的生物力学性能

目的针对组织工程血管的体内培养技术路线，对所制备的具有三层管壁结构的组织工程血管支架的生物力学性能进行测试，并研究了壁厚对支架力学性能的影响，以保证后续的动物体内移植实验能顺利进行。方法采用涂敷，喷涂．滤沥的方法制备了具有三层管壁结构（多孔PLGA层．致密PU层．多孔PLGA层）的可降解组织工程血管支架，用自制的设备测试了其爆破强度和径向顺应性，并对血管支架进行了缝合强度的测试。结果所制备的厚度为0．295mm-0．432mm的三层结构血管支架的径向顺应性为3．80％／100mmHg-0．57％／100mmHg，爆破强度为160kPa～183kPa，缝合强度为0．63N／针～1．52N／针。结论支架的管壁厚度，尤其是中间层厚度，对支架的力学性能有重要影响。增大壁厚可导致径向顺应性急剧下降，爆破强度和缝合强度线性提高。在所制备的样品中，管壁厚度为0．295mm的支架其综合力学性能最优，可满足血管组织工程体内植入的力学性能要求。     

Ex vivo localization of the mouse saposin C activation region for acid beta-glucosidase

Saposin C is a biological activator of acid beta-glucosidase (GCase), the lysosomal hydrolase with activity towards glucosylceramide (GC). In addition, saposin C possesses a functional domain that determines the in vitro and ex vivo neuritogenic effects of prosaposin, the precursor of saposins A, B, C, and D. The domains for enzymatic activation and neuritogenic function segregate in vitro, respectively, to the carboxyl- and amino-terminal halves of human and mouse saposin C. A chimeric mouse saposin C(1-8)B(8-28)C(30-80) was created to obliterate the neuritogenic region by substituting amino acids 9-29 of saposin C with amino acids 8-28 of saposin B. This saposin showed normal in vitro enzymatic activation effects toward GCase, but no neuritogenic activity. An altered prosaposin was made to contain the chimeric saposin C region. Expression of this altered or wild-type prosaposin was driven by the PGK-1 promoter as a transgene in prosaposin knock-out mice. In cultured fibroblasts from such mice, expressed saposins localized to the lysosomal compartments. Metabolic lipid labeling using L-[3-(14)C]serine showed retention or clearance of GC in prosaposin deficient or transgene reconstituted cells, respectively. In addition, sulfatide catabolism, that requires saposin B and arylsulfatase, was also normalized in prosaposin KO cells reconstituted with the transgenes. These data show that the transgenic prosaposins were expressed and processed to functional saposins in fibroblasts. These results also show that the enzymatic activation domain is located at carboxyl-terminal half of saposin C and functions only in the context of the general saposin structure.     

Inhibition of VEGFR2 prevents DMBA-induced mammary tumor formation

Preinvasive mammary pathologies in humans and rat chemical carcinogenesis model systems have an increased microvascular density relative to normal tissue. This suggests the possibility of preventing invasive breast cancer by inhibiting angiogenesis. Vascular endothelial cell growth factor (VEGF) is a potent angiogenic growth factor, commonly involved in tumor-induced angiogenesis. Here, we show that both VEGF and VEGFR2 expression increase with histological progression to invasive disease in the rat 7,12-dimethylbenz[a]anthracene (DMBA) model. Other VEGF receptors, VEGFR1, neuropilin 1 and neuropilin 2, are constitutively expressed throughout progression. To examine whether VEGF signaling is functionally relevant to tumor-induced endothelial tubule formation in vitro and for tumor formation in vivo, we utilized the VEGFR2 inhibitor, ZD6474. In vitro endothelial cell tubulogenesis induced by isolated mammary organoids or carcinoma in situ from DMBA-treated rats is inhibited by ZD6474, in a dose-dependent fashion. The administration of ZD6474 to DMBA-treated rats inhibits the formation of atypical ductal hyperplasia and carcinoma in situ by greater than 95% (P < 0.05), when administered 1 week or 6 weeks post-DMBA initiation. Invasive disease was absent in all ZD6474 cohorts. These data support the hypothesis that progression of DMBA-induced preinvasive mammary pathologies to palpable disease requires angiogenesis via a VEGF-dependent mechanism.     

骨髓间充质干细胞与仿生纳米壳聚糖-胶原复合物修复大鼠胫骨缺损的实验研究

目的： 4周龄SD大鼠骨髓间充质干细胞离体培养后与仿生纳米壳聚糖-胶原（nano chitosan-sodium collagen, nano-CS-COL）形成复合支架，植入SD大鼠胫骨缺损处, 比较修复节段性胫骨缺损的效果, 初步探讨治疗骨缺损的组织工程学方法。方法: 4周龄SD大鼠骨髓间充质干细胞(BMSCs) 离体培养、纯化、鉴定、扩增后在等同于细胞培养的条件下与nano-CS-COL复合培养, 制成MSCs/nano-CS-COL复合物并经电镜扫描证实复合物有细胞生长。制成同种异体SD大鼠胫骨干5mm节段性动物模型, MSCs/nano-CS-COL复合物通过手术移植入动物模型胫骨缺损处, 通过大体观察、X线放射学、组织学对比实验组与对照组、空白组骨缺损修复情况。结果: 术后6、12周实验组与实验对照组放射学检查评价新骨生成有显著差异(P<0.05) 。术后组织学检查新骨生成速度、生成量均有显著差异。实验组标本与正常组基本一致。空白对照组不能自行修复骨缺损, 最后缺损由纤维组织充填。结论: BMSCs是骨组织工程中适宜的种子细胞。Nano-CS-COL复合支架能够与SD大鼠骨髓间充质干细胞体外复合培养, 移植入异体SD大鼠后未见明显免疫排斥反应, 是可以选择的细胞载体。MSCs/nano-CS-COL复合物植入修复鼠胫骨缺损能够加速新骨形成, 修复效果明显优于单纯CS植入组。     

两种细胞表面抗原标记法流式仪检测健康成人T亚群Ⅰ、Ⅱ型细胞比例实验研究

目的了解正常成人T亚群Ⅰ、Ⅱ型细胞比例，并比较以CD3＋CD4双标记法和以CD3＋CD8双标记方法对检测结果的影响。方法全血以PMA和伊能霉素刺激培养4h，以三色标记法流式检测T亚群Ⅰ、Ⅱ型细胞因子阳性细胞的比例。结果CD3、CD8、CD4抗原在刺激后明显下调，但是不影响T亚群比例值。以CD3＋CD8双标记法检测了23例正常成人，n1和Tcl细胞在CD3^＋淋巴细胞中的比例分别为2．6％（0％-23．8％）和2．2％（0％-23．3％）。Th2和Tc2细胞占CD3^＋淋巴细胞2．8％（0．7％-13．3％）和1．6％（0％-5．1％）。以CD3＋CD4双标记法检测了12例正常成人，Th1和Tc1细胞占CD^＋淋巴细胞的比例分别为4．8％（0％-15．6％）和1．8％（0．3％-18．6％），Trh2和Tc2细胞占CD3^＋淋巴细胞的比例分别为2．6％（0％-6．5％）和1．2％（0％-10．6％），均与以CD3＋CD8标记检测的结果无统计学意义。以CD3-FTTC和CD8-PerCP双标记法检测了17例正常人的IL-2表达，IL-2阳性的CD4^＋T细胞占CD3＋淋巴细胞的比例为3．7％（0％-30．0％），高于CD8^＋IL-2^＋T细胞在CD3^＋淋巴细胞中的比例0％（0％-1．7％），P=0．005。结论可以建立有效的流式检测正常人T亚群Ⅰ、Ⅱ型细胞比例方法。以CD3＋CD4双标记或以CD3＋CD8双标记检测分析T亚群的Ⅰ、Ⅱ型细胞比例都是可行的。     

壳聚糖纳米颗粒包裹对鼠白细胞介素2基因表达和调节小鼠免疫效应的影响

本实验制备壳聚糖纳米颗粒 (CNP) ,包裹小鼠白细胞介素 2基因 (mIL 2 )真核表达质粒 (VRMIL 2 ) ,肌注接种 2 1d昆明小鼠 ,观察mIL 2基因体内表达及其对免疫应答和免疫保护的影响。实验结果发现 :CNP包裹VRMIL 2注射小鼠血液中IgG、IgM和IgA不同程度地增多 ,均显著高于CNP包裹空白质粒组 (P <0 .0 5 ) ;其血清中IL 2、IL 4和IL 6的含量明显升高 ,与对照组差异显著 (P <0 .0 5 ) ;外周血液的白细胞和淋巴细胞数量也较对照组显著增加。免疫后 35d以大肠杆菌口服攻毒实验小鼠 ,检测发现 :CNP包裹VRMIL 2组小鼠的上述免疫指标除中性粒细胞外均显著多于对照小鼠 ,VRMIL 2接种小鼠均健康存活 ,而对照小鼠均发病 ;尽管CNP包裹VRMIL 2接种小鼠的体液和细胞免疫指标与未包裹VRMIL 2免疫鼠差异不显著 (P >0 .0 5 ) ,但剂量仅为后者的 1/ 5。这些结果表明 :壳聚糖纳米颗粒包裹VRMIL 2可显著提高外源IL 2基因体内表达水平 ,明显增强体液和细胞免疫水平的效应 ,增强对大肠杆菌的抗病力 ,提示壳聚糖纳米颗粒包裹IL 2基因可明显增强动物的体液和细胞免疫 ,可作为有效的抗感染免疫调节剂。     

葡萄糖和胆固醇对人肝细胞ANGPTL3基因和蛋白质表达的影响

目的 观察葡萄糖和胆固醇对人肝细胞株(L02)血管生成素样蛋白3(angiopoietin-like pro-tein3,ANGPTL3)表达的影响,探讨其与糖尿病和高胆固醇血症的关系.方法 以L02细胞为研究对象,将其分为葡萄糖组(G)和胆固醇组(CH).分别在葡萄糖浓度为5.6 mmol/L(G1)、7.0 mmol/L(G2)、11.1 mmol/L(G3)、28.0 mmol/L(G4)、33.0 mmol/L(G5)的培养液和含胆固醇10 μmol/L、25 μmol/L、50 μmol/L、100 μmol/L的培养液中培养.采用RT-PCR方法检测各组细胞ANGPTL3 mRNA表达量,用Western印迹方法检测其蛋白质表达水平.结果 G3～G5组葡萄糖可剂量依赖性地增加ANGPTL3的mRNA表达(P<0.05);在蛋白质表达水平,G2～G5组与G1组比较差异均有统计学意义(P<0.05);G1～G5组各组间两两比较,除G4组与G5组呈现表达量虽升高,但差异无统计学意义(P>0.05)外,其它各组间差异均有统计学意义(P<0.05).4种胆固醇浓度均可促进L02细胞ANGPTL3的mRNA和蛋白质表达(P<0.05).结论 在一定浓度范围内葡萄糖可剂量依赖性地促进ANGPTL3 mRNA和蛋白质表达;AN-GPTL3的mRNA和蛋白质表达量还受环境胆固醇浓度影响.ANGPTL3的表达可能与糖尿病、高胆固醇血症密切相关.     

Cyclin D1 induced apoptosis maintains the integrity of the G1/S checkpoint following ionizing radiation irradiation

Cell cycle “checkpoints” help to ensure the integrity of normal cellular functions prior to replicative DNA synthesis and/or cell division. Cell kinetic abnormalities, particularly arrests at the G1/S and G2/M cell cycle checkpoints, are induced following exposure to ionizing radiationin vitro. Following irradiation, cellular signaling pathways may lead to G1 arrest and/or apoptosis at the G1/S cell cycle transition point. Transfection of cyclin D1, a G1/S cyclin, into a rat embryo cells (REC) results in cellular populations that overexpress cyclin D1, are transformed morphologically, demonstrate an increased incidence of apoptosis, and are tumorigenic in immune-deficient mice. Despite such phenotypic changes, transfected cell populations maintain the itegrity of the G1 checkpoint following ionizing radiation. The transfected cells overexpressing Cyclin D1 have a statistically significant increase in the incidence of apoptosis as compared to parental REC strains or mock-transfected REC. The work provides further evidence of Cyclin D1 playing a critical role in maintaining the integrity of the G1/S checkpoint, via the activation of apoptotic pathways following exposure to ionizing radiationin vitro.