Marker gene transfer into human haemopoietic cells using a herpesvirus saimiri-based vector

Herpesvirus-based gene therapy vectors offer an attractive alternative to retroviral vectors because of their episomal nature and ability to accommodate large transgenes. Saimiriine herpesvirus 2 (HVS) is a prototypical gamma-2 herpesvirus that can latently infect numerous different cell types. A cosmid-generated HVS vector in which transforming genes have been deleted and the marker gene encoding enhanced green fluorescent protein (HVS-GFP) has been incorporated was evaluated for its potential to transduce CD34+ haemopoietic progenitors selected from cord blood. Expression of GFP could subsequently be readily detected in cells of the erythroid lineage in both CFU-GEMM assays and liquid differentiation cultures. These results confirm the potential of HVS as a candidate vector for gene therapy applications using primitive haemopoietic cells and suggest that it may be applicable to disorders affecting cells of the erythroid lineage.     

人骨髓基质细胞分化为神经元样细胞的研究

目的:探讨人骨髓源性神经干细胞分化为神经细胞的可行性,为中枢神经组织损伤修复寻找种子细胞的理想来源。方法:无菌取成人髂骨骨髓,密度梯度离心分离后获得骨髓基质细胞(bonemarrowstroualcells,BMSCs);在神经干细胞培养液及细胞因子等条件下诱导为神经元样细胞,通过免疫细胞化学方法对诱导后细胞进行鉴定;通过高效液相色谱法(HPLC)检测诱导后细胞合成分泌神经递质去甲肾上腺素(NE)的能力。结果:分离得到的成人BMSCs培养10～14d后,细胞呈半贴壁状,胞体饱满,Nestin抗原染色阳性。培养20d后,在诱导因子作用下进一步分化为神经元样细胞(NLCs),具有细长双极或多极突起,神经核蛋白(NeuN)抗原表达阳性。HPLC检测BMSCs、空白神经干细胞培养液未测到NE,经体外诱导培养8,11d的神经干细胞、体外诱导分化20d的NLCs均可检测到NE,神经干细胞(8,11d)的NE含量为(10.4146±1.0425),(28.3359±3.8371)μg/L小于NLCs(20d)组(52.1342±3.9136)μg/L,差异有非常显著性意义(F=126.64,P=0.0000)。而且随着BMSCs培养天数的增加,其所含的NE浓度也渐增加(P<0.05)。结论:在适宜培养条件及诱导因子联合作用下,人BMSCs可被成功诱导为神经细胞,并具有合成分泌神经递质成分的能力。     

Transplantation of gene-modified human bone marrow stromal cells into mouse-human bone chimeras

Transplantation of BM stromal cells engineered to secrete therapeutic factors could represent a treatment for a large array of hematologic disorders. The aim of this study was to evaluate the susceptibility of human BM stromal cell precursors to retroviral gene transfer, then the ability of those to be transplanted in vivo. We have transduced a recombinant retrovirus encoding the mouse CD2 antigen into STRO-1+ cells selected from adult and fetal BM. Gene-modified stromal cells were injected intravenously into NOD-SCID mice engrafted previously with pieces of human fetal hematopoietic bone. Using nested PCR, transgenic human cells were detected both in the marrow of human bone grafts and in the BM, liver, and spleen of host mice 7 weeks after grafting. These data indicate that BM stromal progenitor cells are targets for retrovirus-mediated gene transfer and can home to hematopoietic tissues on engraftment through the bloodstream of nonconditioned hosts.     

Bone marrow extracellular matrix molecules improve gene transfer into human hematopoietic cells via retroviral vectors.

Direct contact between hematopoietic cells and viral packaging cell lines or other sources of stroma has been shown to increase the efficiency of retroviral-mediated gene transfer into these target cells compared with infection with viral supernatant. We have investigated the role of defined bone marrow extracellular matrix molecules (ECM) in this phenomenon. Here we report that infection of cells adhering to the carboxy-terminal 30/35-kD fragment of the fibronectin molecule (30/35 FN), which contains the alternatively spliced CS-1 cell adhesion domain, significantly increases gene transfer into hematopoietic cells. Two retroviral vectors differing in recombinant viral titer were used. Gene transfer into committed progenitor cells and long-term culture-initiating cells, an in vitro assay for human stem cells, was significantly increased when the cells were infected while adherent to 30/35 FN-coated plates compared with cells infected on BSA-coated control plates or plates coated with other bone marrow ECM molecules. Although gene transfer into committed progenitor cells and to a lesser degree into long-term culture-initiating cells was increased on intact fibronectin as well, increased gene transfer efficiency into hematopoietic cells on 30/35 FN was dependent on CS-1 sequence since infection on a similar FN fragment lacking CS-1 (42 FN) was suboptimal. 30/35 FN has previously been shown by our laboratory and other investigators to mediate adhesion of primitive murine and human hematopoietic stem cells to the hematopoietic microenvironment. Additional studies showed that neither soluble 30/35 FN nor nonspecific binding of hematopoietic cells to poly-L-lysine-coated plates had any appreciable effect on the infection efficiency of these cells. Our findings indicate that hematopoietic stem cell adhesion to specific ECM molecules alters retroviral infection efficiency. These findings should aid in the design of gene transfer protocols using hematopoietic progenitor and stem cells for somatic gene therapy.     

骨髓基质细胞向神经样细胞的分化

目的:有研究表明,在诱导剂β-巯基乙醇或二甲基亚砜与丁羟茴醚的作用下,80%骨髓基质细胞可诱导分化成神经样细胞,并表达神经元特异性蛋白,一些神经营养因子也能诱导骨髓基质细胞分化为神经样细胞.实验拟以三磷酸胞苷二钠为诱导剂,验证其诱导骨髓基质细胞分化为神经样细胞的可行性.方法:实验于2006-03/12在白求恩国际和平医院实验室完成.[1]实验材料:SD大鼠,体质量50～60g,雌雄不限,由河北医科大学实验动物中心提供,实验过程中对动物处置符合动物伦理学标准.[2]实验方法:分离大鼠骨髓基质细胞进行体外培养,传代至第3代时实验组加入三磷酸胞苷二钠诱导剂诱导,对照组不加诱导剂.[3]实验评估:观察细胞分化为神经样细胞的形态变化,并进行免疫组织化学染色鉴定,计算阳性细胞百分比.结果:刚分离的骨髓基质细胞呈圆形,胞体透亮.接种24h后,少量细胞贴壁,72h后大部分细胞贴壁,形态为梭形、圆形、多角形,8～10d细胞达到90%融合,细胞呈长梭形排列呈栅栏状,传代后的细胞约24h完全贴壁,3～7d基本铺满瓶底.诱导后的骨髓基质细胞胞体变圆,突起逐渐伸长,并互相连接成网状,10d后免疫组织化学染色鉴定实验组表达神经元特异性烯醇化酶、神经胶质纤维酸性蛋白阳性细胞百分比明显高于对照组.结论:三磷酸胞苷二钠在体外可诱导骨髓基质细胞分化为神经样细胞.     

骨髓基质细胞向血管内皮细胞分化的体外培养研究

目的研究骨髓基质细胞(marrowstromalcells,MSCs)向血管内皮细胞分化的可能性,以及内皮细胞特异性标志的表达。方法实验选用7周龄清洁级雄性SD大鼠4只,抽取SD大鼠骨髓,进行体外培养和连续传代,获得较纯的MSCs。采用第4代的MSCs,以内皮细胞无血清条件培养液,表皮细胞生长因子(epidermalgrowthfactor,EGF)、碱性成纤维细胞生长因子(basicfibroblastgrowthfactor,bFGF)进行体外诱导,相差显微镜下观察各组细胞形态变化,以免疫组化方法鉴定内皮细胞特征样蛋白VIII因子的表达阳性率,并通过透射电镜观察内皮细胞特异性W-P小体。结果诱导前MSCs多呈扁平、多突起形态,诱导后形态均发生变化,10d细胞呈扁圆形,20d后细胞之间渐呈集落状、铺路石样排列。免疫组化检测VIII因子阳性比例接近70%。透射电镜显示诱导后细胞内出现内皮细胞特异性W-P小体。结论成体中的MSCs在一定诱导条件下可以表现内皮细胞样特征,是临床治疗缺血性疾病理想的移植用种子细胞。     

FLT3配基基因在人骨髓基质细胞中的表达

目的 构建人FLT3配基（FL）逆转录病毒载体，并观察其在人骨髓基质细胞中的表达。方法 用基因重组技术，将FLcDNA插入逆转录病毒载体pLXIN，获得重组载体pLFIN。采用脂质体法将重组质粒pLFIN转染包装细胞PA317，G418筛选抗性克隆，用抗性克隆上清液感染人骨髓基质细胞，RT-PCR和基因组DNA-PCR检测外源基因mRNA的转录及染色体的整合，ELISA法和小鼠CFU-GM集落形成法检测FL蛋白表达量和生物学活性。结果 酶切鉴定表明成功构重组逆转录病毒载体pLFIN；染色体基因组中整合有外源基因FL和Neo；在mRNA和蛋白质水平均可检测到FL表达；24hFL蛋白表达量为4.35ng/ml，活性测试结果显示转染的骨髓基质细胞分泌FL。结论 逆转录病毒介导的FL在骨髓基质细胞中获得表达，并具有良好的生物学活性，为进一步研究转基因骨髓基质细胞对造血调控的影响提供了实验依据。     

c-myc、c-myb基因在白血病骨髓基质细胞中的表达及相关性研究

本研究检测分析c-myc、c-myb原癌基因在白血病细胞和骨髓基质细胞(BMSC)中的表达及其相关性。用逆转录聚合酶链反应(RT-PCR)技术定量分析原癌基因c-myc、c-myb的表达水平,通过流式细胞术分析白血病细胞和BMSC的膜表面抗原,同时采用染色体显带技术分析细胞核型。结果表明:①c-myc、c-myb基因在白血病细胞及其BMSC中均有一定的表达,尤其是在染色体异常的白血病细胞中高表达,其均值分别为1.15±0.38和1.03±0.48,与对照组比较均具有统计学差异(P<0.05);在染色体异常的BMSC中其均值分别为2.08±0.82(P<0.05)和1.46±0.29(P<0.05);②在白血病细胞和BMSC中,c-myc mRNA、c-myb mRNA的表达水平均与血小板计数具有相关性;③在不同预后组中,c-myc mRNA、c-myb mRNA表达呈线性相关;④在白血病细胞及急性组BMSC中原癌基因c-myc、c-myb的表达存在正相关;⑤白血病细胞中c-myc的表达量分别与BMSC中c-myc、c-myb的表达量有相关性。结论:在白血病中降低c-myc或c-myb原癌基因的表达水平可能成为治疗白血病的一种治疗方案。     

脂质体介导骨髓细胞双标志基因转移与体外扩增研究

目的：探讨脂质体介导骨髓细胞基因转移的效率及其表达的稳定性，为基因治疗与基因标志研究提供实验依据。方法：利用脂质体介导，将ＮｅｏＲ和ＬａｃＺ两个标志基因共转导骨髓细胞，通过Ｇ４１８筛选、富集转导阳性细胞，然后扩增这些细胞，观察基因转移率及扩增对转导细胞基因表达稳定性的影响。结果：脂质体介导的骨髓细胞基因转移率为１３．３３％±２．６８％，经Ｇ４１８筛选、富集后，转导阳性细胞可达到４６．０６％±３．４７％。经体外扩增处理，扩增前后无显著性差异。结论：利用脂质体介导的基因转移方法介导骨髓细胞基因转移可获得高效、稳定的表达。     

定向诱导的骨髓基质细胞移植后在大鼠缺血脑组织中的分布

目的探讨人骨髓基质细胞（bone marrow stromal cells，MSCs）源神经细胞体内移植后的分布状况。方法采用密度梯度离心结合贴壁分离法分离、纯化人MSCs。MSCs经bFGF预诱导24h及阿魏酸钠（Sodium Ferulate）诱导24h后用于移植。采用线栓法复制大鼠局灶性脑缺血再灌注动物模型．缺血2h后行再灌注，24h后经栓塞侧颈内动脉注入诱导后的MSCs（5&#215;10^6/0．8ml）（n=61。2w后取脑组织行冰冻切片．通过检测人细胞核特异抗体MAB1281来鉴定移植的人MSCs。结果MSCs经阿魏酸钠诱导后．细胞逐渐圆缩并伸出突触．呈现神经细胞样形态。在移植大鼠脑内可检测到MAB1281呈阳性表达的人MSCs．且MSCs主要分布在缺血侧损伤灶的周围，明显高于对侧同部位及其它脑区。结论人MSCs源神经细胞移植后在大鼠脑内存活并主要聚集在脑内缺血灶的周围。     

定向诱导的骨髓基质细胞移植后在大鼠缺血脑组织中的分布

目的探讨人骨髓基质细胞（bone marrow stromal cells，MSCs）源神经细胞体内移植后的分布状况。方法采用密度梯度离心结合贴壁分离法分离、纯化人MSCs。MSCs经bFGF预诱导24h及阿魏酸钠（Sodium Ferulate）诱导24h后用于移植。采用线栓法复制大鼠局灶性脑缺血再灌注动物模型．缺血2h后行再灌注，24h后经栓塞侧颈内动脉注入诱导后的MSCs（5×10^6/0．8ml）（n=61。2w后取脑组织行冰冻切片．通过检测人细胞核特异抗体MAB1281来鉴定移植的人MSCs。结果MSCs经阿魏酸钠诱导后．细胞逐渐圆缩并伸出突触．呈现神经细胞样形态。在移植大鼠脑内可检测到MAB1281呈阳性表达的人MSCs．且MSCs主要分布在缺血侧损伤灶的周围，明显高于对侧同部位及其它脑区。结论人MSCs源神经细胞移植后在大鼠脑内存活并主要聚集在脑内缺血灶的周围。     

外源性人骨形态发生蛋白-2基因在兔骨髓基质细胞中的稳定表达及其诱导成骨作用

目的:通过观察携带外源性人骨形态发生蛋白-2(humanbonemor-phorgeneticprotein-2,hBMP-2)基因的骨髓基质细胞(bonemarrowstromalcells,MSCs)生物学性状变化和检测MSC分泌hBMP-2的含量,探讨hBMP-2基因在MSC中的稳定表达。方法:应用脂质体介导的方法将携带hBMP-2基因的重组载体PcD-NA3-hBMP2导入体外培养的兔MSC中,用G418筛选获得阳性细胞,应用ELISA检测MSC表达并分泌hBMP-2水平,并绘制细胞的生长曲线。结果:从细胞的培养基中可检测到hBMP-2蛋白质。转染后阳性细胞的倍增时间和生长时间没有因为目的基因的导入而改变,与正常培养的细胞相比差异无显著性意义。结论:hBMP-2基因在MSC中可获得较高水平的稳定表达并能分泌hBMP-2蛋白质,为骨缺损修复中内源性hBMP-2作用的发挥提供可能。     

Viral vectors for gene transfer into antigen presenting cells

Crucial insights for vaccine development have come from examining how the immune system responds to antimicrobial vaccines, as well as to viral vectors employed for gene therapy. The effectiveness of a vaccine depends upon both the method of antigen delivery and the presentation of antigen to lymphocytes. Much focus has turned to delivering antigens to dendritic cells, to promote clinically beneficial T- and B-cell responses. Recombinant viral vectors represent a powerful vehicle to deliver genes encoding microbial- or tumor-derived antigens to generate clinically beneficial immunity. Dendritic cell-based and viral vector-based vaccines are currently being evaluated in clinical trials as a means of inducing antitumor immunity.     

骨髓基质细胞转化为神经细胞的实验研究

背景研究发现骨髓基质细胞移植后能够游走到全身不同部位,增生转化为相应细胞,能不同程度恢复损伤器官功能.以证实骨髓基质细胞可在体外转化成中胚层和内胚层细胞.目的探讨骨髓基质细胞体外转化为神经细胞的可能性.设计设立对照的重复测量设计.地点和对象哈尔滨医科大学附属第一医院骨科.健康雄性SD大鼠,120～150 g,清洁级,由哈尔滨医科大学附属第一医院动物室提供.干预骨髓基质细胞原代培养、传代后使用3种不同方法诱导.行大体观察,免疫组织化学及细胞电生理检查和长期培养研究.主要结局观察指标骨髓基质细胞诱导、细胞免疫组化和细胞电生理检测结果.结果第1诱导方案加入诱导剂1 h 50%转化成神经细胞,90 min 70%～80%转化为神经细胞.第2诱导方案加入诱导剂24 h 10%转化成神经细胞.第3诱导方案BMSC 40%加入,24 h 90%转化成神经细胞,胞体小突触短.BMSC 80%时加入,转化的神经细胞呈巢状排列占40%.骨髓基质细胞体外可诱导为突触明确的神经细胞(诱导率＞80%);诱导后细胞表面有神经特异性抗原NSE,GFAP表达;同时具有早期神经细胞电流特性.结论骨髓基质细胞可横向转化为早期神经细胞.     

Retroviral-mediated transfer of the human glucocerebrosidase gene into cultured Gaucher bone marrow.

Gaucher disease, a lysosomal glycolipid storage disorder, results from the genetic deficiency of an acidic glucosidase, glucocerebrosidase (GC). The beneficial effects of allogeneic bone marrow transplantation (BMT) for Gaucher disease suggest that GC gene transduction and the transplantation of autologous hematopoietic stem cells (gene therapy) may similarly alleviate symptoms. We have constructed a retroviral vector, L-GC, produced by a clone of the amphotropic packaging cell line PA317, which transduces the normal human GC cDNA with high efficiency. Whole-marrow mononuclear cells and CD34-enriched cells from a 4-yr-old female with type 3 Gaucher disease were transduced by the L-GC vector and studied in long-term bone marrow culture (LTBMC). Prestimulation of marrow with IL-3 and IL-6, followed by co-cultivation with vector-producing fibroblasts, produced gene transfer into 40-45% of the hematopoietic progenitor cells. The levels of GC expression in progeny cells (primarily mature myelomonocytic) produced by the LTBMC were quantitatively analyzed by Northern blot, Western blot, and glucocerebrosidase enzyme assay. Normal levels of GC RNA, immunoreactive protein, and enzymatic activity were detected throughout the duration of culture. These studies demonstrate that retroviral vectors can efficiently transfer the GC gene into long-lived hematopoietic progenitor cells from the bone marrow of patients with Gaucher disease and express physiologically relevant levels of GC enzyme activity.     

基因转染骨髓间充质干细胞诱导分化为胰岛素分泌细胞

骨髓间充质干细胞在体外一定条件下分化成为胰岛细胞,既可以解决胰岛移植中供体紧缺的问题,又能够通过自体移植避免免疫排斥,还将避开胚胎干细胞研究所涉及的伦理道德问题,是治疗糖尿病的理想干细胞来源.研究发现可以将胰岛素基因及其他必需的基因直接导入来自糖尿病患者的原代细胞或其他成体干细胞如肝细胞、肠道上皮K细胞、成纤维细胞及肝脏肿瘤细胞等,使其转变为胰岛素分泌细胞即转基因的胰岛素分泌细胞.目前国际上主要的研究方向是如何将胰岛素基因有效地导入靶细胞,并使之呈生理模式表达.     

体外无血清培养基条件下诱导人骨髓基质细胞为神经干细胞的特征

背景:体外诱导骨髓基质细胞向神经元样细胞分化的方法主要是应用抗氧化剂如β-巯基乙醇、全反式维甲酸、丹参等,这些诱导方法分化的主要是神经元样细胞,这种细胞是否具有神经元的功能有待进一步观察。目的:观察体外无血清培养基条件下人骨髓基质细胞向神经细胞分化的特点。设计:观察实验。单位:潮州市中心医院。材料:实验于2004-04/2005-12在潮州市中心医院完成。成人骨髓来源于3例骨折患者的股骨和胫骨骨髓,获得患者及其家属的同意及潮州市中心医院伦理委员会批准。重组人碱性成纤维细胞生长因子和重组人表皮生长因子为Sigma公司产品;鼠抗波形蛋白单克隆抗体、鼠抗S100单克隆抗体、鼠抗TrkC单克隆抗体、鼠抗髓鞘基础蛋白单克隆抗体、SP-9000试剂盒和即用型AEC为北京中山公司产品;鼠抗GFAP单克隆抗体、兔抗巢蛋白多克隆抗体、鼠抗神经元特异性烯醇化酶单克隆抗体和鼠抗神经微丝200单克隆抗体在武汉博士德公司购买;鼠抗βⅢ管蛋白单克隆抗体为Sigma公司产品。方法:在手术骨折内固定过程中获得成人骨髓,缓冲液冲洗后分离细胞,原代培养的细胞融合时传代培养,细胞种植在神经干细胞的N2培养基或B27培养基,同时加入20μg/L的碱性成纤维细胞生长因子及表皮生长因子,放入含体积分数0.05CO2的培养箱中37℃常规培养,相差显微镜下观察骨髓基质细胞在无血清培养基中的形态变化,培养2d后采用免疫细胞化学方法检测骨髓基质细胞的神经细胞相关标志物的表达。主要观察指标:骨髓基质细胞的形态变化及神经细胞相关标志物的表达。结果:①从成年人的骨髓中分离出骨髓基质细胞,在体外生长形态类似成纤维细胞,可以维持在未分化状态稳定增殖,体外扩增可超过10代。骨髓基质细胞在无血清神经干细胞的培养基中生长状态类似神经干细胞,可以形成典型的球状结构。②细胞球可表达神经干细胞的标志物波形蛋白和巢蛋白;细胞分化可以表达神经元的标志物神经微丝200、神经元特异性烯醇化酶、TrkC和βⅢ管蛋白;部分分化的细胞表达胶质纤维酸性蛋白和S100,说明细胞分化为星形胶质细胞。结论:骨髓基质细胞在神经干细胞的无血清的培养基中细胞的生长状态、表达的标志物和分化的细胞类型与神经干细胞类似。     

构建携带VEGF121-FLAG和hrGFP-1基因腺病毒表达载体在骨髓基质干细胞中的表达

背景:血管内皮生长因子具有促进血管生成的作用,在骨缺损的治疗研究中运用较多,但其异构体VEGF121的研究较少.目的:构建携带VEGF121-FLAG和hrGFP-1基因的腺病毒表达载体并观测其在骨髓基质干细胞中的表达.方法:以pTG19T-VEGF121为模板利用PCR技术突变VEGF121基因以去除VEGF121基因中终止密码子,之后在基因序列前后分别加入NotⅠ和XhoⅠ酶切位点,并将得到的基因亚克隆至pMD19-T质粒上,双酶切pMD19-T-VEGF121和pShuttle-CMV-IRES- hrGFP-1质粒,凝胶回收小片段和大片段,后进行连接反应,完成穿梭质粒的构建.重组病毒物理滴度测定后感染骨髓基质干细胞,在荧光显微镜下观察荧光强度.结果与结论:经酶切鉴定及基因测序证实重组腺病毒质粒构建成功, 荧光显微镜下观察表明, 感染重组腺病毒的骨髓基质干细胞有明显的绿色荧光表达.可见构建的携带VEGF121-FLAG和hrGFP-1基因的腺病毒表达载体可在真核细胞表达, 有可能用于缺血性疾患的基因治疗.