pEGFPN1-GDNF真核表达载体的构建及其表达

目的 构建人胶质细胞源性神经营养因子(GDNF)基因真核表达载体并观察其在COS-7细胞内的表达.方法 应用RT-PCR从U251细胞总RNA中扩增GDNF cDNA,将其克隆至真核表达载体pEGFPN1,经酶切鉴定及序列分析后,以Fugene HD介导转染COS-7细胞,应用免疫细胞化学和Western blot鉴定其在细胞内的表达.结果 RT-PCR产物为650bp的特异片段,重组质粒pEGFPN1-GDNF经双酶切产生650bp和4.7kb的片段,测序分析结果与文献报道结果完全一致.将其转染COS-7细胞后,免疫细胞化学、Western blot结果表明GDNF蛋白能在COS-7细胞中正确表达.结论 成功构建了pEGFPN1-GDNF真核表达载体,为进一步开展帕金森病的基因治疗研究奠定了基础.     

pcDNA3/BDNF真核表达载体的构建☆

背景：脑源性神经营养因子(brain-derived neurotrophic factor,BDNF)作用广泛,但属于生物大分子,不能通过血脑屏障。基因治疗是目前解决脑源性神经营养因子给药途径最有希望的方案。 目的：拟构建大鼠脑源性神经营养因子基因真核表达载体。 方法：采用反转录聚合酶链式反应技术从SD大鼠脑组织提取总RNA,扩增脑源性神经营养因子基因cDNA序列,并将其克隆到真核表达载体pcDNA3中,分别取10 g质粒pcDNA3和纯化的目的基因分别进行EcoR Ⅰ、xho Ⅰ双酶切。将目的基因片段和pcDNA3载体连接,转入感受态DH5α细胞中,经酶切鉴定后送上海博亚生物技术有限公司测序。 结果与结论：RT-PCR产物为749 bp的特异片段,重组质粒pcDNA3/BDNF酶切后产生 749 bp和5 446 bp的片段,DNA测序证实749 bp片段的碱基序列与大鼠脑源性神经营养因子基因序列完全一致,成功构建了pcDNA3/BDNF重组质粒。     

稳定表达GDNF基因的骨髓基质干细胞对多巴胺能神经元的作用

目的 制备胶质细胞源性神经生长因子(GDNF)基因修饰的骨髓基质干细胞(MSCs)，观察其对多巴胺能神经元的作用，探索治疗帕金森氏病的新途径。方法 应用逆转录聚合酶链反应(RT-PCR)方法从新生小鼠大脑皮层细胞克隆出GDNF cDNA片断，以pEGFP-C1为载体导入MSCs，制备稳定表达GDNF基因的MSCs工程细胞，采用联合培养的技术通过倒置显微镜和免疫组织化学的方法观察MSCs和GDNF基因修饰的MSCs工程细胞与多巴胺能神经元之间的相互作用。结果 MSCs和GDNF基因修饰的MSCs工程细胞均能促进多巴胺能神经元的存活和生长，MSCs工程细胞作用更强。结论 成功构建了GDNF基因修饰的MSCs工程细胞，该细胞对多巴胺能神经元有明显营养保护作用，在帕金森病治疗中可能有重要价值。     

人sTRAIL基因载体构建及其在真皮干细胞的表达

背景：基于肿瘤坏死因子(tumour necrosis factor,TNF)可溶性相关凋亡诱导配体(soluble related apoptosis inducing ligand, sTRAIL)抗瘤的生物特性,克隆sTRAIL基因,构建其真核表达载体,为肿瘤细胞凋亡的实验研究奠定基础。目的：构建真核表达载体pEGFP-N1/sTRAIL,并转染真皮干细胞,以探究sTRAIL基因导入真皮干细胞的表达情况。方法：采用RT-PCR二步法,以人胎盘组织总RNA为模板,扩增sTRAIL的cDNA序列,将其克隆入pMD18-T载体,随后亚克隆入载体pEGFP-N1中,构建其真核瞬时表达载体pEGFP-N1/sTRAIL,以Fugene 6转染技术,将sTRAIL基因导入真皮干细胞。倒置显微镜下观测转染后真皮干细胞生长变化及sTRAIL在其中的表达等情况。RT-PCR法对目的基因转染的真皮干细胞进行鉴定。结果与结论：克隆到sTRAIL基因的cDNA序列,成功构建了其真核表达载体,该真核表达载体能携带sTRAIL基因在真皮干细胞中正常表达。倒置显微镜下观测到转染后真皮干细胞生长状态与未转染的真皮干细胞无差异。以经sTRAIL基因转染的真皮干细胞该基因组DNA为模板,用RT-PCR法能扩增到sTRAIL基因cDNA序列。     

腺病毒介导的GDNF基因转移体外表达及生物学活性研究

为利用重组腺病毒介导的胶质细胞源性神经营养因子（GDNF）基因转移治疗帕金森病（PD）提供依据。方法：采用免疫组化、RT－PCR及ELISA定量分析观察人GDNF腺病毒（Ad-GDNF)在大鼠星形胶质 PC12细胞的表达,通过观察病毒直接感染及病毒感染的PC12细胞上清对中脑原代培养细胞中的TH阳性细胞（DA能神经元）生存能力和形态分化的影响来验证其生物学活性。结果Ad-GDNF在星形胶质细胞、PC12细胞及大鼠中脑原代培养细胞均可有效表达,其表达产物对中脑DNA能神经元的生存和形态分化均有显著的促进作用。结论：腺病毒介导的GDNF基因转移可在体外有效表达,且表达产物具有生物学活性,提示该手段在PD治疗方面具有良好的应用前景。     

人NR2B基因真核表达载体的构建及其在CHO细胞中的表达

目的 克隆人NR2B基因,构建其真核表达载体,获得暂态表达NR2B的CHO细胞.方法 RT-PCR方法克隆人NR2B基因,并插入真核表达载体pcDNA3.1中,将该重组载体转染至CHO细胞.通过RT-PCR、Western blot及间接免疫荧光鉴定细胞中NR2B的表达,通过流式细胞仪检测细胞的凋亡.结果 成功获得人NR2B基因,转染的CHO细胞可检测到NR2B的表达,表达NR2B的CHO细胞并不会凋亡.结论 成功克隆和构建了人NR2B基因的真核表达载体,并在CHO细胞中得到了表达.     

BDNF基因重组逆转录病毒表达载体pLEGFP-BDNF的构建与鉴定

目的构建脑源性神经营养因子(BDNF)基因重组逆转录病毒表达载体。方法根据 BDNF基因已知序列,设计合成一对引物并导入HindⅢ和BamH Ⅰ酶切位点;从大鼠海马组织提取总 RNA,逆转录聚合酶链反应(RT-PCR)获得编码BDNF的基因片段,与克隆载体pMD 18-T Simple连接构建pMDT-BDNF质粒;经HindⅢ、BamHⅠ双酶切,获得BDNF基因片断再克隆至逆转录病毒载体 pLEGFP-N1中构建重组质粒pLEGFP-BDNF。结果限制性内切酶酶切分析和PCR法鉴定表明为正确重组子,测序结果证实与已知序列吻合。结论构建的重组逆转录病毒表达载体 pLEGFP-BDNF含有序列正确的大鼠BDNF基因,可以作为今后治疗老年性痴呆动物模型转基因实验的基因来源。     

重组小鼠pEGFP-GDNF质粒的构建及其在骨髓基质干细胞中的表达

目的 克隆小鼠胶质细胞源性神经营养因子(GDNF)并转染骨髓基质于细胞，制备转基因工程细胞。方法 应用逆转录聚合酶链反应(RT-PCR)方法从新生小鼠大脑皮层细胞克隆出GDNFcDNA片断，以pEGFP-C1质粒为载体导入骨髓基质于细胞，用流式细胞仪检测转染率，用荧光显微镜和免疫细胞化学方法检测蛋白质的表达。结果 流式细胞仪检测转染率约50％，荧光显微镜下见转染pEGFP／GDNF质粒的骨髓基质干细胞(MSC)发出明亮的绿色荧光，免疫细胞化学方法检测发现转基因MSC抗GDNF蛋白染色成强阳性，正常MSC染色成阴性。结论 成功制备了高效表达外源性基因GDNF的MSC。绿色荧光蛋白作为报告基因可反应GDNF表达情况。     

pDsRed-C1-CDNF真核表达载体在大鼠骨髓间质干细胞中的表达*

背景：骨髓间质干细胞是一类具有多向分化能力的成体干细胞,目前,已有将其作为细胞载体对帕金森病进行治疗的相关报道。 目的：构建pDsRed-C1-CDNF真核表达载体,并诱导其在大鼠骨髓间质干细胞中表达。 方法：通过RT-PCR的方法从小鼠组织中扩增出CDNF基因片段,并在其两端引入Xho I、BamH I限制性内切酶酶切位点,然后将其克隆至pDsRed-C1真核载体,构建pDsRed-C1-CDNF真核表达载体,并通过Lipofectin2000将其转染至大鼠骨髓间质干细胞中。 结果与结论：pDsRed-C1-CDNF真核表达载体经双酶切、单酶切、PCR及测序验证正确,提示已成功构建pDsRed-C1-CDNF真核表达载体并已转染至大鼠骨髓间质干细胞中。     

稳定表达GDNF／EGFP融合基因的骨髓基质干细胞对多巴胺能神经元的保护作用

目的　 构建GDNF基因修饰的骨髓基质干细胞 ,并观察其对多巴胺能神经元的营养支持作用。方法　 应用逆转录聚合酶链反应 (RT PCR)方法从新生小鼠大脑皮层细胞克隆出GDNFcDNA片段 ,以pEGFP C1为载体导入骨髓基质干细胞 (MSCs) ,制备稳定表达GDNF/EGFP融合基因的MSCs工程细胞 ,用联合培养的技术通过倒置显微镜和免疫组织化学的方法观察MSCs和GDNF基因修饰的MSCs工程细胞与多巴胺能神经元的相互作用。 结果　MSCs和GDNF基因修饰的MSCs工程细胞共培养均能促进多巴胺能神经元的存活和生长 ,MSCs工程细胞作用更强。 结论　 成功构建了GDNF基因修饰的MSCs工程细胞 ,该细胞对多巴胺能神经元有明显营养保护作用 ,在帕金森病治疗中可能有重要价值     

Gene transfer of glial cell line-derived neurotrophic factor promotes functional recovery following spinal cord contusion

Neuronal cell death and the failure of axonal regeneration cause a permanent functional deficit following spinal cord injury (SCI). Administration of recombinant glial cell line-derived neurotrophic factor (GDNF) has previously been reported to rescue neurons following severe SCI, resulting in improved hindlimb locomotion in rats. In this study, thus, GDNF gene therapy using an adenoviral vector (rAd-GDNF) was examined in rats following SCI induced by dropping the NYU weight-drop impactor from a height of 25 mm onto spinal segment T9-T10. To evaluate the efficacy of intraspinal injection of recombinant adenovirus into the injured spinal cord, we observed green fluorescent protein (GFP) gene transfer in the contused spinal cord. GFP was effectively expressed in the injured spinal cord, and the most prominently transduced cells were astrocytes. The expression of GDNF was detected only in rats receiving rAd-GDNF, not the controls, and remained detectable around the injured site for at least 8 days. Open-field locomotion analysis revealed that rats receiving rAd-GDNF exhibited improved locomotor function and hindlimb weight support compared to the control groups. Immunohistochemical examination for the neuronal marker, calcitonin gene-related peptide (CGRP), showed an increase in CGRP+ neuronal fibers in the injured spinal cord in rats receiving rAd-GDNF treatment. Collectively, the results suggest that adenoviral gene transfer of GDNF can preserve neuronal fibers and promote hindlimb locomotor recovery from spinal cord contusion. This research should provide information for developing a clinical strategy for GDNF gene therapy.     

抗坏血酸联合胶质细胞源性神经营养因子诱导神经干细胞向多巴胺能神经元分化的研究

目的 研究抗坏血酸(AA)和胶质细胞源性神经营养因子(GDNF)对神经干细胞向多巴胺能神经元分化的影响.方法 从新生24h内的sD大鼠脑组织分离和培养神经干细胞,进行神经干细胞鉴定.第二代神经干细胞诱导培养基中分别给予AA或(和)GDNF,10d后终止诱导,进行DA能神经元特异性标记物酪氨酸羟化酶(TH)和多巴胺转运蛋白的免疫细胞化学检测和TH基因的RT-PCR检测.结果 各诱导组均检测到TH mRNA的表达;与对照组比较,AA及GDNF均能增加NSC向TH阳性细胞分化的比率(P<0.05);与单独运用100μmol/LAA或10ng/mlGDNF组比较,联合诱导组可明显提高NSCs向TH阳性细胞分化的比率(P<0.05).结论 AA和GDNF均能促进NSCs向DA能神经元分化,两者联合诱导后分化作用得到进一步加强.     

氟西汀对大鼠星形胶质细胞分泌的胶质源性神经营养因子的影响

目的 探讨氟西汀对大鼠星形胶质细胞分泌的胶质源性神经营养因子(GDNF)的影响.方法 以氟西汀干预体外培养的大鼠海马星形胶质细胞,通过四甲基偶氮唑盐法(MTT)检测不同浓度氟西汀对细胞活力的影响;采用酶联免疫吸附测定法(ELISA)检测细胞培养液GDNF浓度及Real-time PCR法检测GDNFmRNA的表达.结果 (1)氟西汀浓度超过35 μmol/L浓度时,可降低细胞活性,差异有统计学意义(P<0.01或P<0.05);(2)10 μmol/L氟西汀干预星形胶质细胞不同时间后,48 h组细胞培养液GDNF浓度[(68±13)fg/L]高于0 h组[(32±11)fg/L]、6 h组[(34±12)fg/L]、12 h组[(41±17)fg/L]、24 h组[(45±13)fg/L],差异均有统计学意义(P均<0.01);(3)不同浓度氟西汀作用星形胶质细胞48 h后,10 μmol/L浓度组的细胞培养液GDNF浓度[(64±17)fg/L]高于0 μmol/L[(39±15)fg/L]和1 μmoVL浓度组[(39±18)fg/L],差异均有统计学意义(P均<0.05);(4)氟西汀作用星形胶质细胞48 h后,撤离氟西汀24 h后星形胶质细胞仍明显分泌GDNF,差异有统计学意义(P<0.01或P<0.05);(5)不同浓度氟西汀作用星形胶质细胞24 h后,10 μmol/L和20 μmol/L浓度组细胞GDNFmRNA表达量[分别为(0.008 1±0.001 1)和(0.006 3±0.000 3)]高于0 μmol/L、1 μmol/L及5 μmol/L浓度组[分别为(0.003 1±0.000 7)、(0.003 9±0.000 3)和(0.004 1±0.000 2)],差异均有统计学意义(P均<0.01).结论 氟西汀可能通过促进星形胶质细胞GDNF的分泌来发挥其神经保护作用.     

Transplantation of mesenchymal stem cells from human umbilical cord versus human umbilical cord blood for peripheral nerve regeneration

BACKGROUND: Mesenchymal stem cells (MSCs) appear to be a good alternative to Schwann cells in the treatment of peripheral nerve injury. Fetal stem cells, like umbilical cord blood (UCB) and umbilical cord (UC) stem cells, have several advantages over adult stem cells.OBJECTIVE: To assess the effects of UC-derived MSCs (UCMSCs) and UCB-derived MSCs (UCBMSCs) in repair of sciatic nerve defects. DESIGN, TIME AND SETTING: A randomized controlled animal experiment was performed at the laboratory of Department of Oral and Maxillofacial Surgery, Seoul National University Dental Hospital, from July to December 2009. MATERIALS: UCMSCs were provided by the Research Institute of Biotechnology, Dongguk University. UCBMSCs were provided by the Laboratory of Stem Cells and Tumor Biology, College of Veterinary Medicine, Seoul National University. Dulbecco's modified Eagle's medium (DMEM) was purchased from Gibco-BRL, USA. METHODS: Seven-week-old Sprague-Dawley rats were randomly and evenly divided into three groups: DMEM, UCBMSCs, and UCMSCs. A 10-mm defect in the left sciatic nerve was constructed in all rats. DMEM (15 μL) containing 1 × 106 UCBMSCs or UCMSCs was injected into the gap between nerve stumps, with the surrounding epineurium as a natural conduit. For the DMEM group, simple DMEM was injected. MAIN OUTCOME MEASURES: At 7 weeks after sciatic nerve dissection, dorsal root ganglia neurons were labeled by fluorogold retrograde labeling. At 8 weeks, electrophysiology and histomorphometry were performed. At 2, 4, 6, and 8 weeks after surgery, sciatic nerve function was evaluated using gait analysis.RESULTS: The UCBMSCs group and the UCMSCs group exhibited similar sciatic nerve function and electrophysiological indices, which were better than the DMEM group, as measured by gait analysis (P < 0.05). Fluorogold retrograde labeling of sciatic nerve revealed that the UCBMSCs group demonstrated a higher number of labeled neurons; however, the differences were not significant. Histomorphometric indices were similar in the UCBMSCs and UCMSCs groups, and total axon counts, particularly axon density (P < 0.05), were significantly greater in the UCBMSCs and UCMSCs groups than in the DMEM group. CONCLUSION: Transplanting either UCBMSCs or UCMSCs into axotomized sciatic nerves could accelerate and promote sciatic nerve regeneration over 8 weeks. Both treatments had similar effects on nerve regeneration.     

脐血间充质干细胞与帕金森病

间充质干细胞(mesenchymal stem cells,MSCs)作为一种成体干细胞,具有未分化细胞的特性,能高效率的自我更新,并且有着向多种成熟细胞分化的潜能,在生物医学和组织工程中具有巨大的科研价值[1].骨髓是第一个被报道含有MSCs的组织来源,也是如今临床应用的主要来源,但获取过程有创,易导致感染、出血、慢性疼痛,并且其增殖、分化潜能均随年龄的增长而降低,因此对于老年患者的效果得不到保证.     

Human umbilical cord blood stem cells upregulate matrix metalloproteinase-2 in rats after spinal cord injury

Matrix metalloproteinases (MMPs) are a large family of proteolytic enzymes involved in inflammation, wound healing and other pathological processes after neurological disorders. MMP-2 promotes functional recovery after spinal cord injury (SCI) by regulating the formation of a glial scar. In the present study, we aimed to investigate the expression and/or activity of several MMPs, after SCI and human umbilical cord blood mesenchymal stem cell (hUCB) treatment in rats with a special emphasis on MMP-2. Treatment with hUCB after SCI altered the expression of several MMPs in rats. MMP-2 is upregulated after hUCB treatment in spinal cord injured rats and in spinal neurons injured either with staurosporine or hydrogen peroxide. Further, hUCB induced upregulation of MMP-2 reduced formation of the glial scar at the site of injury along with reduced immunoreactivity to chondroitin sulfate proteoglycans. Blockade of MMP-2 activity in hUCB cocultured injured spinal neurons reduced the protection offered by hUCB which indicated the involvement of MMP-2 in the neuroprotection offered by hUCB. Based on these results, we conclude that hUCB treatment after SCI upregulates MMP-2 levels and reduces the formation of the glial scar thereby creating an environment suitable for endogenous repair mechanisms.     

黄芩甙诱导人脐血间充质干细胞分化为神经元样细胞

目的探讨中药黄芩甙体外诱导人脐血间充质干细胞（MSCS）分化为神经元样细胞的可行性及其可能的机制。方法无菌条件下采集正常足月胎儿的脐带血,经肝素抗凝,用相对密度1．077的淋巴细胞分离液分离脐血单个核细胞,加入含黄芩甙50μmol/L的液体培养体系中进行扩增培养。取扩增培养2周的人脐血MSCS进行诱导实验。实验共分3组：诱导组（诱导液和维持液均含黄芩甙300～400μmol/L）；对照1组（诱导液和维持液均不含黄芩甙及其它抗氧化剂）；对照2组（诱导液和维持液均含3mmol/Lβ-巯基乙醇、20g/L二甲基亚砜和20mmol/L丁化羟基苯甲醚,不含黄芩甙）。诱导30min后开始在倒置显微镜下动态观察人脐血MSCS生长情况及诱导前后形态学变化。各组分别在诱导6h、24h、7d留取标本制作细胞爬片,用免疫细胞化学染色法评价神经细胞特异性烯醇化酶（NSE）和微管相关蛋白2（MAP-2）阳性细胞的表达率。用Hoechest 33258染色法评价各组细胞存活率。结果黄芩甙诱导7d后,人脐血MSCS形成较典型的神经元样细胞形态,免疫细胞化学染色显示黄芩甙诱导组NSE、MAP-2阳性细胞表达率及细胞存活率分别为77．2％±9．8％、76．6％±6．2％、86．5％±5．2％,显著高于对照1、2组（P＜0．01）。分别为4．6％±0．7％、0．7％±0．5％、45．7％±8．3％和68．9％±4．5％、51．5％±5．2％、71．6％±6．4％。结论黄芩甙能诱导人脐血MSCS分化为神经元样细胞,其诱导作用温和、稳定而持久,其诱导机制可能与黄芩甙的抗氧化、调控细胞NF-κB的活性从而刺激多种细胞因子的生成有关。     

Intraspinal transplantation of motoneuron-like cell combined with delivery of polymer-based glial cell line-derived neurotrophic factor for repair of spinal cord contusion injury

To evaluate the effects of glial cell line-derived neurotrophic factor transplantation combined with adipose-derived stem cells-transdifferentiated motoneuron delivery on spinal cord con-tusion injury, we developed rat models of spinal cord contusion injury, 7 days later, injected adipose-derived stem cells-transdifferentiated motoneurons into the epicenter, rostral and caudal regions of the impact site and simultaneously transplanted glial cell line-derived neuro-trophic factor-gelfoam complex into the myelin sheath. Motoneuron-like cell transplantation combined with glial cell line-derived neurotrophic factor delivery reduced cavity formations and increased cell density in the transplantation site. The combined therapy exhibited superior promoting effects on recovery of motor function to transplantation of glial cell line-derived neurotrophic factor, adipose-derived stem cells or motoneurons alone. These ifndings suggest that motoneuron-like cell transplantation combined with glial cell line-derived neurotrophic factor delivery holds a great promise for repair of spinal cord injury.     

尼莫地平对大鼠面神经损伤的保护作用及GDNF表达的影响

目的 探讨尼莫地平对大鼠面神经损伤的保护作用及对胶质细胞源性神经生长因子(GDNF)表达的影响.方法 96只大鼠按随机数字表法分为假手术组、单纯损伤组、尼莫地平预处理组、尼莫地平后处理组,后三组建立大鼠面神经电损伤模型.应用HE染色、Western blotting等方法,观察大鼠面神经损伤后不同时期(1、3、6月)GDNF的动态表达变化及尼莫地平不同给药时间对其表达的影响.结果 与单纯损伤组相比,尼莫地平预处理组大鼠面神经损伤程度减轻,GDNF表达升高,持续时间延长;尼莫地平预处理组GDNF表达和尼莫地平后处理组间比较差异有统计学意义(P＜0.05);尼莫地平后处理组GDNF表达在3月、6月时与单纯损伤组比较差异无统计学意义(P＞0.05).结论 预防性应用尼莫地平可以保护面神经,其机制可能是通过调节GDNF的表达而实现的.

Abstract：

Objective To study the protective function of nimodipine on facial nerve injury and its effect on the expression of glial cell line-derived neurotrophic factor (GDNF). Methods Ninety-six SD rats were randomly divided into sham-operated group, facial nerve injury group, nimodipine pretreatment group, and nimodipine post-treatment group. Rat models of facial nerve injury in thc later 3groups were established. The dynamic changes of expression of GDNF were observed by HE staining and Western blotting in different treatment groups and at different time points (1, 3 and 6 months after the injury). Restdts Compared with the facial nerve injury group, the nimodipine pretreatment and post-treatment groups had significantly less severe nerve damage and significantly up-rcgulated expression of GDNF (P＜0.05). The expression of GDNF in the nimodipine pretreatment group was statistically higher than that in the nimodipine post-treatment group (P＜0.05). However, the expression of GDNF in the nimodipine post-treatment group was not statistically different from that in the facial nerve injury group 3 and 6 months after the injury (P＞0.05). Conclusion Nimodipine has significant facial nerve protective effect, and one of the mechanisms of nimodipine to protect the facial nerve is to regulate the GDNF expression.