Neurturin基因的克隆及其在C17.2神经干细胞中表达的研究

目的 探讨Neurturin(NTN)基因转染的C17．2神经干细胞移植后对帕金森病(PD)大鼠模型的保护作用，为其提供基因修饰的神经干细胞。方法 用RT—PCR方法获取Prepro-NTN cDNA，并克隆至pBlueskipt Ⅱ载体中，再将Prepro-NTN基因克隆至pcDNA3．1—hygro真核表达载体中，经量Lipofectamine 2000转染C17．2神经干细胞，挑选稳定表达的克隆，用RT—PCR及Western Blot印迹分析鉴定。结果 pcDNA3．1—hygro-NTN质粒转染C17.2神经干细胞后有5个稳定表达的克隆生长，克隆1有NTN蛋白的高表达。结论 获得了稳定表达NTN蛋白的C17．2神经干细胞克隆，为移植治疗PD打下了坚实的实验基础。     

Caspase3基因克隆及在癫痫样放电海马神经元中的表达

目的 探讨海马神经元癫痫样放电引起神经元丢失的机制。方法 采用RT—PCR法克隆大鼠全长Caspase3cDNA，然后采用原位杂交和流式细胞技术检测了海马神经元癫痫模型中Caspase3基因表达和神经元凋亡情况。结果 得到了大鼠的全长Caspase3cDNA，发现海马神经元癫痫样放电后出现Caspase3基因表达和神经元凋亡的现象。结论 癫痫样放电启动Caspase3表达，继而介导神经元凋亡。     

Neurturin基因在体外培养的大鼠骨髓基质细胞中的表达

目的构建携带一种神经营养因子Neurturin(NTN)基因的腺病毒(Ad),使其在骨髓基质细胞(BMSCs)中表达。方法采用分子克隆技术,构建携带NTN基因的Ad载体,用脂质体法转染、包装HEK293细胞,制备具有感染活性的Ad-NTN病毒粒子;用病毒上清液感染原代培养的大鼠BMSCs,并用免疫细胞化学方法检测阳性细胞。用W estern B lot检测转染Ad-NTN的BMSCs细胞上清液。结果经酶切鉴定和DNA测序,得到重组Ad-NTN,对被感染的HEK293细胞进行病毒滴度测定,每毫升病毒贮存液可达1×108.5半数组织培养感染量(TC ID50);将病毒贮存液感染BMSCs,获得了表达NTN的BMSCs,阳性率为65%。W estern B lot检测证实BMSCs上清液中出现特异性NTN条带。结论重组Ad携带的NTN基因能够在BMSCs中表达。     

大鼠胶质细胞源性神经营养因子的基因克隆及其在大肠杆菌中的表达

用逆转录一聚合酶链反应（ＲＴ－ＰＣＲ）以大鼠纹体总ＲＮＡ为模板，扩增了大鼠胶质细胞源性神经营养因子（ｒＧＤＮＦ）成熟序列的ｃＤＮＡ片段，将此ｃＤＮＡ克隆到载体ｐＧＥＭ－Ｔ中，对重组质粒进行限制酶切分析和序列测定，确定为含ｒＧＤＮＦｃＤＮＡ的重组质粒，将该ｒＧＤＮＦｃＤＮＡ重组到融合表达载体ｐＧＥＸ－１λＴ内，在大肠杆菌中较高的表达。     

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.     

白细胞介素3基因cDNA克隆与转导及其在脐血CD34+细胞中的表达

背景：单份脐血难以满足成人造血干细胞移植的要求,需对其进行体外扩增,这不仅需要较长的时间和较高的培养条件,而且容易导致干细胞自身分化,从而影响移植效果。 目的：克隆人白细胞介素3基因cDNA,构建其真核表达载体并转导脐血CD34+细胞,观察白细胞介素3的表达情况。 设计、时间及地点：细胞-基因组学体外实验,于2008年在承德医学院完成。 材料：健康成人外周血由承德市中心血站提供,脐血由承德市妇幼保健院提供,提供者对实验均知情同意。 方法：采集健康成人外周血,应用Ficoll密度梯度法分离单个核细胞,免疫磁珠法分离脐血CD34+细胞。提取白细胞介素3 mRNA,应用RT-PCT扩增白细胞介素3 cDNA,构建真核表达载体pcDNA3/IL-3。设立2组：实验组利用基因枪技术将pcDNA3/IL-3导入脐血CD34+细胞中,对照组未行转染。 主要观察指标：采用人白细胞介素3 ELISA试剂盒检测脐血CD34+细胞上清液中白细胞介素3水平。 结果：扩增的白细胞介素3基因cDNA理论上应为616 bp,实际PCR产物经琼脂糖凝胶电泳后,紫外线下可见预期大小的条带,反转录合成的cDNA完整。BamHⅠ和XbaⅠ双酶切后,电泳可见616 bp的插入片段,与白细胞介素3基因序列相同。转染第1~7天,实验组脐血CD34+细胞上清液中白细胞介素3水平明显高于未转染对照组(t=3.46,P < 0.05)。 结论：白细胞介素3基因cDNA克隆成功,并成功构建了真核表达质粒pcDNA3/IL-3,pcDNA3/IL-3能在脐血CD34+细胞中短期有效表达。     

人KiSS-1基因克隆及其慢病毒载体的构建**★

背景：慢性病毒载体技术是目前转基因中最有效和最成功的方法，技术操作简便。 目的：克隆转移抑制基因KiSS-1基因不含信号肽的表达序列，构建人KiSS-1基因的慢病毒表达载体。 设计、时间及地点：开放性实验于2006-09/2007-12在福建师范大学发育学院实验室完成。 材料：载体pNL-IRES2-EGFP由福建师范大学发育学院实验室保存。 方法：从人正常胎盘组织中提取总RNA，经反转录-聚合酶链反应得到KiSS-1基因开放阅读框cDNA序列，并将其克隆到慢病毒载体pNL-IRES2-EGFP中，构建其表达质粒pNL-IRES2-EGFP-KiSS-1。 主要观察指标：KiSS-1目的基因片段的克隆，重组表达质粒pNL-IRES2-EGFP-KiSS-1的酶切鉴定及测序。 结果：经酶切鉴定和基因序列测定，证实重组入载体pNL-IRES2-EGFP的片段为目的基因开放阅读框的核苷酸序列。 结论：成功构建了重组质粒pNL-IRES2-EGFP-KiSS-1。     

人野生型parkin基因真核表达载体的构建及其在PC12细胞中的表达

目的 克隆人野生型parkin基因并构建真核表达载体pCDNA3．1—parkin，将重组质粒转染PC12细胞获得高表达人野生型parkin基因的PC12细胞克隆。方法 从胎脑组织中提取总RNA，用RT—PCR方法获得人野生型parkin基因的全长cDNA，插入pCR2．1—TA克隆载体中进行序列测定，测序正确后将其亚克隆至表达载体pCD—NA3．1，利用脂质体将重组质粒转染PC12细胞，经G418筛选获得抗性细胞克隆，采用RT—PCR和Western Blot方法鉴定人野生型parkin基因在PC12细胞中的过表达。结果 经限制性内切酶酶切图谱分析和DNA序列测定证实目的基因已插入重组质粒，RT—PCR和Western Blot证明经G418筛选得到的转基因PC12细胞克隆中存在人野生型parkin基因的表达。结论 成功构建了人野生型parkin基因的真核表达载体，获得了稳定表达人野生型parkin基因的PC12细胞克隆，为进一步研究parkin的生物学功能以及parkin在帕金森病发病机制中的作用奠定了良好的基础。     

与人染色体结构维持基因6高度同源应力可诱导基因克隆及其表达☆

背景：已往研究显示，心肌对短暂缺血再灌的应答与多种基因表达改变有关，但它们的特性尚未明确。 目的：克隆和分析应力可诱导基因特性以探讨心肌短暂缺血再灌损伤的分子机制。 设计：对比观察的动物实验。 单位：中南大学湘雅医院血液科。 材料：选用16只健康德国Landrace家猪，体质量21~39 kg，由德国巴特瑙海姆马普所生理与临床研究所实验心脏病学研究室提供。对家猪的处置遵循美国生理学会的规章。按随机数字表法将16只家猪分为缺血再灌注手术组（n =14）和假手术组（n =2）。缺血再灌注组动物在第二次缺血再灌注后0，30，90 min 3个时间点进行观察。每组又分为缺血组织和对照组织两部分。 方法：实验于1998-07/2007-05分别在德国巴特瑙海姆马普生理与临床研究所实验心脏病学研究室和中南大学湘雅医院血液科完成。将动物麻醉后，开胸，稳定30 min后，缺血再灌注组动物阻塞左冠状动脉前降支10 min，灌注30 min，再次阻塞10 min，时间点为(10’-30’ -10’)，再灌注30 min(时间点为10’-30’-10’-30’)；再灌注90 min(时间点为10’-30’-10’-90’)后取心肌组织。假手术组不进行缺血再灌注。按预定观察时间点将动物分别麻醉后处死，取左冠状动脉前降支区域的组织作为缺血组织，左冠状动脉弦支区域的组织作为对照组织。首先，以cDNA片段RKD7.1作为探针筛选猪心脏cDNA文库并通过DNA序列测定分析所克隆基因的DNA序列。同时，通过短暂阻断和再灌注猪左冠状动脉前降支形成缺血再灌心肌。然后，从该缺血再灌猪心肌组织提取总RNA后用于Northern杂交分析，以基因杂交后灰度值与其18S rRNA灰度值的比值作为基因表达的相对水平。 主要观察指标：克隆基因DNA和氨基酸序列分析及克隆基因表达分析。 结果：16只健康德国Landrace家猪均进入结果分析。通过筛选文库，克隆到一个含有3461个碱基对的cDNA。DNA序列测定和检索分析显示该cDNA与可能编码DNA修复蛋白的人类染色体结构维持基因6具有86%的相同性，并与鼠染色体结构维持基因6具有84%的相同性。进一步分析发现，由此cDNA推导出的最长多肽链含有1 007个氨基酸残基，它与人类染色体结构维持基因6蛋白具有92%相同性, 与鼠染色体结构维持基因6蛋白具有89%相同性。为此，该cDNA取名为人类染色体结构维持基因6猪同源基因。Northern杂交结果显示，猪染色体结构维持基因6 mRNA在缺血再灌心肌的表达为增加并且其mRNA在所检测的各种器官中均存在达。 结论：从猪心肌克隆到一个应力可诱导猪染色体结构维持基因6，它与人类染色体结构维持基因6具有高度的同源性，猪染色体结构维持基因6或者与其他分子可能共同参与缺血再灌所致猪心肌DNA损伤的早期修复。     

人BIGH3基因克隆表达对兔角膜基质细胞黏附和迁移的影响***☆○

背景：BIGH3蛋白位于角膜上皮和基质层,在基质层高表达,先前研究已经发现BIGH3蛋白能促进角膜上皮创伤愈合,为此进一步探讨其对角膜基质创伤愈合的影响。 目的：构建人BIGH3基因的原核表达载体,观察其对角膜细胞与细胞外基质黏附和迁移的作用。 方法：PCR扩增BIGH3基因的ORF阅读框,并通过Kpn I和Sal I插入到原核表达载体pET32a(+)中。经PCR、酶切和序列测定方法鉴定重组质粒。将重组质粒转入BL21(DE3)表达,IPTG诱导表达人BIGH3融合蛋白, 并进行SDS-PAGE电泳分析和Western blot检测分析;以Ni-NTA树脂对蛋白纯化与复性,作用于体外培养的兔角膜细胞,用MTT法分析其对细胞与细胞外基质黏附的影响,采用改良的Boyden微孔膜双槽法观察BIGH3蛋白对角膜细胞迁移的影响。 结果与结论：重组质粒经PCR、酶切与DNA测序证实插入了pET32a(+)载体中。通过IPTG诱导,成功的表达融合蛋白在包涵体中,经SDS-PAGE电泳分析,出现了一条新生的蛋白条带,Western blot也证实了该蛋白具有与BIGH3抗体特异性的结合能力。MTT法和Boyden微孔膜双槽法分别证明所表达的BIGH3融合蛋白可促兔角膜细胞黏附和迁移。成功构建了人BIGH3重组融合蛋白表达质粒,纯化了该基因的原核表达产物,并通过重组融合蛋白BIGH3能促进兔角膜细胞与细胞外基质黏附及迁移,而验证了重组BIGH3蛋白的活性。     

脑组织移植和神经干细胞研究进展

综述了近年来广泛开展的神经组织和细胞移植的各种主要方法及其进展。着重对神经干细胞这一神经科学的前沿课题进行了详细的复习。并对神经干细胞的研究方法,神经营养因子和神经干细胞的关系,神经干细胞的分化诱导及共临床方面的应用前景作了阐述。     

Viral vector-mediated gene therapy for Parkinson's disease

Parkinson's disease (PD) is a progressive neurodegenerative disorder that affects 1% of the population above the age of 60. The cause of the disease remains unknown. The histopathological hallmarks of the disease are intracytoplasmic Lewy bodies and dopaminergic striatal insufficiency secondary to a loss of dopaminergic neurons in the substantia nigra pars compacta (SN). Pharmacological treatment options for PD are often limited by the ability of prodopaminergic drugs to function within the nigrostriatal system, without activating other dopaminergic, but non-nigrostriatal regions, of the CNS. Even if this obstacle is overcome, considerations regarding the chronic availability of the drug can limit drug utility. Gene delivery systems are ideal for delivering therapeutic molecules to site specific regions of the CNS. Via gene therapy, a piece or pieces of DNA placed into a carrying vector encoding for a substance of interest is introduced into cells. While there are many ways to apply this technology, this review will focus on in vivo gene therapy as it applies to Parkinson's disease. Using stereotaxic surgery, vectors can be introduced into specific target areas in the brain and deliver genes encoding for therapeutic molecules. By delivering genes using gene therapy approaches, a therapeutic molecule can be delivered chronically in a site-specific fashion, diminishing unwanted side effects and repeated interventions to obtain useful levels of the drug. Throughout this review, we discuss the potential for gene delivery aimed at enhancing dopamine production or providing neuroprotection for nigrostriatal neurons to serve as a therapeutic strategy for PD.     

GDNF partially protects grafted fetal dopaminergic neurons against 6-hydroxydopamine neurotoxicity

Rats were given unilateral 6-hydroxydopamine (6-OHDA) lesions and subsequently received transplants of fetal ventral mesencephalic tissue into the denervated striatum. Four weeks later transplanted animals were tested for graft-mediated reduction of amphetamine-induced rotational behavior. Subsequently, transplanted animals received an intrastriatal injection of either GDNF (10 microg) or citrate buffer into a site lateral to the transplant, and then 6 h later received an injection of either 4.0 microg of 6-OHDA, 8.0 microg of 6-OHDA, or vehicle using the same stereotaxic coordinates that were used for the GDNF/citrate buffer injection. Animals were re-tested for amphetamine-induced rotational behavior 2 weeks later. Histological analysis revealed a significant reduction in the number of cell bodies immunostained for tyrosine hydroxylase (TH+) within the transplant for those animals pretreated with an intrastriatal injection of citrate buffer and subsequently given either dose of 6-OHDA. Transplanted animals pretreated with GDNF and subsequently administered 8.0 microg of 6-OHDA showed a significant reduction of TH+ neurons within the transplant compared to controls, however TH+ cell counts for this group remained significantly higher than the TH+ cell counts for the group of animals receiving the same dose of 6-OHDA but pretreated with citrate buffer. GDNF pretreatment completely protected TH+ cell bodies against 4.0 microg of 6-OHDA. Rotational scores indicated that GDNF provided only partial protection against 6-OHDA neurotoxicity in terms of transplant function. For both groups of transplanted animals receiving GDNF pretreatment and 6-OHDA injections, amphetamine-induced rotational scores dropped below the scores for animals pretreated with citrate buffer but remained significantly higher than the scores for transplanted animals that were not injected with 6-OHDA. Both histological and behavioral measures indicate GDNF partially protects integrated transplants against neurotoxic insult.     

双相障碍与脑源性神经营养因子外周血mRNA和蛋白表达相关性的研究

目的 探讨脑源性神经营养因子(BDNF)外周血mRNA表达和血清蛋白水平与双相障碍、双相躁狂和双相抑郁的关系.方法 应用TaqMan探针及荧光实时定量逆转录-聚合酶链反应方法,检测并比较双相障碍组(61例)、双相躁狂组(29例)、双相抑郁组(32例)和对照组(61名)外周血白细胞BDNF基因的mRNA表达水平的差异;采用酶联免疫吸附方法测定血清BDNF浓度;应用17项汉密尔顿抑郁量表(HAMD17)和Young氏躁狂量表(YMRS)评定患者抑郁症状严重程度和躁狂症状的严重程度,采用Pearson相关分析分析BDNF基因mRNA表达水平和血清蛋白浓度与HAMD17和YMRS评分的关系.结果 (1)双相障碍组BDNF基因mRNA相对表达水平(0.0077±0.0019)较对照组(0.0096±0.0028)下降(t=-3.74,P＜0.01);双相躁狂组(0.0081±0.0023)、双相抑郁组(0.0073±0.0024)与对照组3组间BDNF基因mRNA相对表达水平的差异有统计学意义(F=7.55,P＜0.01),且双相躁狂组和双相抑郁组均低于对照组(P＜0.05或P＜0.01).(2)双相障碍组BDNF血清蛋白浓度低于对照组(t=-2.90,P＜0.01);双相躁狂组、双相抑郁组与对照组3组间BDNF血清蛋白浓度的差异有统计学意义(F=4.21,P＜0.05);双相躁狂组和双相抑郁组BDNF血清蛋白浓度均低于对照组(P均＜0.05),但双相躁狂组与双相抑郁组比较差异无统计学意义(P＞0.05).(3)双相躁狂组BDNF基因mRNA表达水平及血清蛋白浓度与YMRS评分未见相关(P＞0.05),双相抑郁组BDNF基因mRNA表达水平及血清蛋白浓度与HAMD17评分未见相关(P＞0.05).结论 双相障碍与BDNF水平下调可能相关,这种下降贯穿于躁狂相和抑郁相,而且BDNF的变化不会因双相障碍患者极性的变化而处于两极状态.     

Brain-derived neurotrophic factor enhances function rather than survival of intrastriatal dopamine cell-rich grafts

Brain-derived neurotrophic factor (BDNF) has been shown to promote the survival of dopaminergic neurons from the substantia nigra in cell culture. In order to assess whether a similar survival-promoting effect is present also in vivo, we grafted fetal nigral tissue to the dopamine-depleted striatum of 6-hydroxydopamine-lesioned rats receiving two-week intraventricular infusions or daily intrastriatal injections of BDNF, NGF, or vehicle. Wheninfused chronically at a high dose (12 μg/day) into the lateral ventricle, BDNF caused a behavioral syndrome of reduced food and water intake, body weight loss, and locomotor hyperactivity in comparison to NGF- and vehicle-infused graft recipients. NGF-infused graft recipients displayed a transient weight loss during the first week of infusion. At 15 days, amphetamine-induced turning was significantly attenuated to 3% of pregraft values in BDNF-infused recipients, whereas functional graft effects were not present in NGF- or vehicle-infused animals. Survival of tyrosine hydroxylase-immunoreactive graft cells, however, was similar in all treatment groups. Notably, NGF- and BDNF-infusions led to a significant size increase of cholinergic host neurons in the medial septal nucleus and the vertical limb of the diagonal band ipsilateral to the infusion, wheras there was no cholinergic neuron hypertophy in vehicle-infused animals. Daily intrastriatalinjections of BDNF (2 μg) produced no weight loss or locomotor hyperactivity, but also enhanced functional graft effects in BDNF-injected, as compared to vehicle-injected animals. Survival rates of grafted tyrosine hydroxylase-immunoreactive cells were, however, similar in both groups. We conclude that, using the administration methods chosen for this study, BDNF may enhance the functional capacity but not the survival of grafted dopamine neurons.     

The mouse MPTP model: gene expression changes in dopaminergic neurons

Parkinson's disease (PD) is a common neurodegenerative disorder, characterized by the progressive loss of dopaminergic neurons in the substantia nigra. Although valuable animal models have been developed, our knowledge of the aetiology and pathogenic factors implicated in PD is still insufficient to develop causal therapeutic strategies aimed at halting its progression. The neurotoxicity induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is one of the most valuable models for analysing pathological aspects of PD. In this paper we studied the gene expression patterns underlying the pathogenesis of MPTP-induced neurodegeneration. We treated young and old C57BL/6 mice with different schedules of MPTP to induce degenerative processes that vary in intensity and time-course. During the first week after intoxication we used nonradioactive in situ-hybridization to investigate the expression patterns of genes associated with (i) dopamine metabolism and signalling; (ii) familial forms of PD; (iii) protein folding and (iv) energy metabolism. MPTP injections induced different severities of neuronal injury depending on the age of the animals and the schedule of administration as well as a significant degeneration in the striatum. In situ hybridization showed that MPTP intoxication initiated a number of gene expression changes that (i) were restricted to the neurons of the substantia nigra pars compacta; (ii) were correlated in intensity and number of changes with the age of the animals and the severity of histopathological disturbances; (iii) displayed in each a significant down-regulation by the end of one week after the last MPTP injection, but (iv) varied within one MPTP regimen in expression levels during the observation period. The subacute injection of MPTP into one-year-old mice induced the most severe changes in gene expression. All genes investigated were affected. However, alpha-synuclein was the only gene that was exclusively up-regulated in MPTP-treated animals displaying cell death.     

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。