携带同源盒基因HOXA9的逆转录病毒载体的构建和鉴定

目的构建携带同源盒基因(homeobox gene)HOXA9的逆转录病毒载体,并建立稳定产毒的包装细胞株。方法 PCR扩增HOXA9基因编码区全长序列克隆至逆转录病毒载体MSCVneo,经酶切、测序鉴定。将重组载体脂质体转染包装细胞系PT67,以G418筛选稳定产毒细胞株。收集病毒悬液并测定病毒滴度。结果重组逆转录病毒载体MSCVneo经酶切、测序鉴定正确。将筛选所得的高效产毒细胞株命名为PT67/MSCVneo-HOXA9,测定病毒滴度为5×105CFU/ml。结论成功构建了携带HOXA9基因的逆转录病毒载体,建立了稳定、高效、准确产生逆转录病毒的细胞株。     

同源盒基因HoxA10的重组逆转录病毒载体及稳定包装细胞株的建立和鉴定

本研究构建携带同源盒基因hoxA10的重组逆转录病毒载体,并建立稳定产毒的包装细胞株。通过PCR扩增获得hoxA10基因编码区全长序列,克隆至逆转录病毒载体MSCVneo,并测序鉴定插入的hoxA10基因。将重组载体及空载体经脂质体分别转染包装细胞系PT67,以G418筛选稳定产毒细胞株。收集病毒悬液并测定病毒滴度。结果表明：重组逆转录病毒载体MSCVneo插入的hoxA10基因序列正确。将筛选所得的高效产毒细胞株命名为PT67／MscVneo、PT67／MSCVneo—hoxA10。测定病毒滴度分别为5×10^5CFU／ml、4×10^4CFU／ml。结论：成功构建了同源盒基因hoxA10的重组逆转录病毒载体,建立了稳定、高效、准确产生逆转录病毒的细胞株,为探讨hoxA10基因在造血干细胞的增殖和分化功能提供了实验基础。     

重组逆转录病毒pLNCX2-TH的构建及鉴定

目的：构建并鉴定重组逆转录病毒载体pLNCX2-TH,建立稳定的PT67产病毒细胞系,并观察其对NIH3T3细胞的感染效率,为基因调控干细胞分化治疗帕金森病奠定基础。方法：采用基因工程技术,将酪氨酸羟化酶（TH）基因片段克隆至逆转录病毒载体pLNCX2-MCS上,鉴定后用脂质体法转染PT67细胞进行病毒包装、扩增,最后通过感染NIH3T3细胞,测定病毒滴度。结果：酶切、测序结果与TH基因重组逆转录病毒载体的预期结果一致,病毒滴度达1.6×106pfu/mL,对NIH3T3细胞有较高的感染效率。结论：应用基因工程技术可成功构建重组逆转录病毒pLNCX2-TH,建立PT67产病毒细胞系,为帕金森病的基因治疗创造了条件。     

稳定表达bcr-abl融合基因片段的鼠SP2/0细胞系的建立

为了建立稳定表达bcr-abl融合基因片段的SP2/0细胞系,从重组克隆载体pGEMbcr-abl中酶切出bcr-abl融合基因片段,并将其亚克隆进逆转录病毒载体pLXSN中。脂质体介导重组逆转录病毒载体pLXSNbcr-abl转染包装细胞PT67,采用G418筛选后获得稳定产病毒的包装细胞。收集病毒感染NIH/3T3细胞,加G418筛选后进行逆转录病毒滴度的测定,计算病毒效价为2×107CFU/ml。结果表明,收集病毒上清感染SP2/0细胞(H-2d),经G418筛选获得了稳定表达bcr-abl融合基因片段的SP2/0细胞株。经特异性PCR扩增和RT-PCR反应扩增,从基因组整合和基因表达水平证实获得了能稳定表达bcr-abl融合基因片段的鼠SP2/0细胞系。结论:成功建立了表达bcr-abl融合基因的鼠SP2/0细胞系,这一肿瘤细胞模型可作为研究bcr-abl基因疫苗的有效实验工具,为检验bcr-abl基因疫苗激发小鼠CTL应答的研究奠定物质基础。     

内源性胰岛素替代疗法中葡萄糖激酶基因逆转录病毒表达载体的构建

背景由于胰岛细胞分离技术难度较大,目前糖尿病细胞移植治疗尚缺乏理想的细胞来源。目的构建葡萄糖激酶(Glucokinase,GK)基因逆转录病毒表达载体及稳定的产毒细胞系,为构建具有葡萄糖反应性胰岛素分泌能力的胰岛代理细胞打下基础,可望为糖尿病提供一种更符合生理要求的内源性胰岛素替代疗法。设计非随机非对照的实验研究。地点、材料和干预本研究在解放军第三军医大学附属新桥医院中心实验室进行。将GK质粒(pCMV4-GKZ1)经EcoR1/BamH1双酶切后亚克隆至逆转录病毒载体PLXSN,构建逆转录病毒表达载体PLX-GK,用酶切法和测序法对重组体进行鉴定。然后脂质体介导逆转录病毒表达载体PLX-GK转入包装细胞PA317,筛选病毒滴度较高的稳定产毒细胞系,PCR鉴定。主要观察指标①重组逆转录病毒载体构建与鉴定结果。②病毒滴度鉴定及PCR结果。结果成功构建GK基因逆转录病毒表达载体,经酶切及测序证明目的基因插入位点和读码框架正确、无突变;产毒细胞系的平均病毒滴度为6.8×108CFU/L,筛选出一株病毒滴度为1.8×109CFU/L稳定产毒细胞系PA317/GK,PCR证实GK基因整合入细胞基因组。结论成功构建了携GK基因的逆转录病毒表达载体及高滴度的产毒细胞系。     

新型骨形态发生蛋白2反转录病毒载体的构建及活性检测

背景:骨形态发生蛋白是一种具有潜在活性的蛋白质,当骨组织损伤时其迅速增加并活性的增强,与载体复合能修复动物骨缺损,但将其用做基因治疗的研究未见报道.目的:构建表达重组人骨形态发生蛋白2基因的重组反转录病毒载体,探讨其在成骨细胞中的生物学作用.方法:根据Genbank中人骨形态发生蛋白2基因序列设计并合成骨形态发生蛋白2特异性引物,高保真PCR扩增骨形态发生蛋白2基因,同源重组法将骨形态发生蛋白2 PCR片段连接与克隆载体pDNR-CMV,构成pDNR-CMV-BMP2,经酶切、PCR和测序鉴定后,将重组质粒pDNR-CMV-BMP2和反转录病毒空质粒pLP-LNCX以loxP位点进行同源重组,构成反转录病毒载体pLP-LNCX-BMP2,转染入包装细胞PT67进行病毒包装,并用NIH3T3细胞进行病毒滴度测定;将反转录病毒感染人成骨细胞,四甲基偶氮唑盐法检测细胞生长变化,转染48 h后Western blotting检测骨形态发生蛋白2蛋白表达.结果与结论:pDNR-CMV-BMP2质粒Sall和EcoRI双酶切、PCR及测序结果均正确,重组质粒pLP-LNCX-BMP2经氯霉素及蔗糖筛选得到的阳性克隆骨形态发生蛋白2 PCR结果阳性,酶切产物与预期相一致;病毒载体pLP-LNCX-BMP2转染PT67后,G418筛选可得到稳定细胞克隆,其上清液中病毒滴度可达到5×10~8pfu;四甲基偶氮唑盐检测中反转录病毒组与正常对照组相比,72 h细胞抑制率无明显差别(P＞0.05),转染48 h后Western blotting可见骨形态发生蛋白2蛋白高表达.结果说明,实验成功克隆了骨形态发生蛋白2基因并构建其反转录病毒表达载体.     

内源性胰岛素替代疗法中葡萄糖激酶基因逆转录病毒表达载体的构建

背景：由于胰岛细胞分离技术难度较大，目前糖尿病细胞移植治疗尚缺乏理想的细胞来源。目的：构建葡萄糖激酶(Glucokinase，GK)基因逆转录病毒表达载体及稳定的产毒细胞系，为构建具有葡萄糖反应性胰岛素分泌能力的胰岛代理细胞打下基础，可望为糖尿病提供一种更符合生理要求的内源性胰岛素替代疗法。设计：非随机非对照的实验研究。地点、材料和干预：本研究在解放军第三军医大学附属新桥医院中心实验室进行。将GK质粒(pCMV4-GKZl)经EcoR1／BamH1双酶切后亚克隆至逆转录病毒载体PLXSN，构建逆转录病毒表达载体PLX-GK，用酶切法和测序法对重组体进行鉴定。然后脂质体介导逆转录病毒表达载体PLX-GK转入包装细胞PA317，筛选病毒滴度较高的稳定产毒细胞系，PCR鉴定。主要观察指标：①重组逆转录病毒载体构建与鉴定结果。②病毒滴度鉴定及PCR结果。结果：成功构建GK基因逆转录病毒表达载体，经酶切及测序证明目的基因插入位点和读码框架正确、无突变；产毒细胞系的平均病毒滴度为6．8&;#215;10^8CFU／L，筛选出一株病毒滴度为I．8&;#215;10^9CFU／L稳定产毒细胞系PA317／GK，PCR证实GK基因整合入细胞基因组。结论：成功构建了携GK基因的逆转录病毒表达载体及高滴度的产毒细胞系。     

EB病毒BZLF1N基因的克隆与序列分析

目的:克隆EB病毒BZLFIN基因编码区的cDNA并对其序列进行分析.方法:采用RT-PCR方法,从B95-8细胞获得BZLF1N基因的cDNA,克隆至pGEM-TEasy载体,选择阳性克隆并进行序列测定.结果:构建的重组载体中含有EB病毒BZLF1N基因的全长序列,与Genebank公布的序列完全一致.结论:获得EB病毒BZLF1N基因的克隆,为进一步的研究奠定了基础.     

神经生长因子重组反转录病毒载体在神经干细胞中的表达

背景：神经生长因子属于生物大分子,难以透过血脑屏障,而反转录病毒载体能稳定地将外源基因插入并整合到宿主细胞基因组内,适于作为基因治疗的载体。 目的：探讨神经生长因子基因重组反转录病毒表达载体在神经干细胞中的表达情况。 方法：将SD大鼠神经生长因子基因重组反转录病毒表达载体pLEGFP-NGF通过脂质体Lipofectamine 2000转染包装细胞PT67,经G418筛选后,收集阳性克隆病毒上清,用于感染神经干细胞,用ELISA检测神经生长因子基因的表达,并利用 PC12细胞检验神经生长因子的生物学活性,同时观察神经生长因子对神经干细胞存活、分化的影响。 结果与结论：重组了神经生长因子基因的反转录病毒液感染神经干细胞后能表达外源性神经生长因子蛋白,该蛋白能促使PC12细胞数量增多,突起明显变长,并能增加神经干细胞的存活数量,促进神经干细胞分化。结果说明整合了神经生长因子基因的神经干细胞能表达外源性神经生长因子,表达的神经生长因子对神经干细胞的存活及分化均有促进作用。     

基因治疗帕金森病的分子生物学研究:神经营养因子Neurturin基因克隆及其真核表达

目的:克隆中国人Neurturin基因,重组携带Neurturin基因的真核表达载体,为研究Neurturin基因治疗帕金森病提供分子生物学基础。方法:实验于2003-03/2004-05在北京市神经再生修复研究重点实验室完成。采用RT-PCR方法从人胎儿脑中获取NeurturincDNA,将其克隆至pGEM-Easy-T载体中。测序鉴定后,重组携带Neurturin基因的反转录病毒载体pLPCX-Neurturin;通过脂质体将重组载体转染PT67包装细胞系,用病毒上清感染NIH3T3细胞系以检测病毒滴度。结果:RT-PCR扩增到人NeurturincDNA片段,序列与Genebank登录的序列一致;将Neurturin基因亚克隆至反转录病毒载体得到插入方向正确的重组载体pLPCX-Neurturin,病毒上清滴度为5×104CFU/mL。结论:获得人Neurturin基因cDNA序列,检测到Neurturin基因在真核细胞中表达,并得到较高滴度的病毒上清。     

Lipoprotein-associated phospholipase A2

Lipoprotein-associated phospholipase A2 (LP-PLA2) is an emerging inflammatory marker that is used to assess the risk for cardiovascular disease (CVD) and associated events. Several epidemiologic studies have demonstrated an independent association between plasma Lp-PLA2 concentration and risk for cardiovascular events. HMG-CoA reductase inhibitors (statins) and fenofibrates can reduce Lp-PLA2 concentrations in plasma, and orally active, specific Lp-PLA2 inhibitors have been developed and are in clinical trials to evaluate the potential of Lp-PLA2 as a therapeutic target. This article reviews recent studies of Lp-PLA2 in the setting of CVD, discusses the proposed mechanisms of action of Lp-PLA2, and describes methods for measurement and their clinical application. Recent evidence that suggests Lp-PLA2's potential usefulness as a therapeutic target also is reviewed.     

Potential Therapeutic Applications of Adenosine A2A Receptor Ligands and Opportunities for A2A Receptor Imaging

Adenosine A_2A receptors (A_2ARs) are highly expressed in the human striatum, and at lower densities in the cerebral cortex, the hippocampus, and cells of the immune system. Antagonists of these receptors are potentially useful for the treatment of motor fluctuations, epilepsy, postischemic brain damage, or cognitive impairment, and for the control of an immune checkpoint during immunotherapy of cancer. A_2AR agonists may suppress transplant rejection and graft‐versus‐host disease; be used to treat inflammatory disorders such as asthma, inflammatory bowel disease, and rheumatoid arthritis; be locally applied to promote wound healing and be employed in a strategy for transient opening of the blood–brain barrier (BBB) so that therapeutic drugs and monoclonal antibodies can enter the brain. Increasing A_2AR signaling in adipose tissue is also a potential strategy to combat obesity. Several radioligands for positron emission tomography (PET) imaging of A_2ARs have been developed in recent years. This review article presents a critical overview of the potential therapeutic applications of A_2AR ligands, the use of A_2AR imaging in drug development, and opportunities and limitations of PET imaging in future research.     

Inactivation of CYP2A6 and CYP2A13 during nicotine metabolism

Nicotine is the major addictive agent in tobacco. The primary catalyst of nicotine metabolism in humans is CYP2A6. However, the closely related enzyme CYP2A13 is a somewhat better catalyst. CYP2A13 is an extrahepatic enzyme that is an excellent catalyst of the metabolic activation of the tobacco-specific carcinogen 4-(methylnitrosamine)-1-(3-pyridyl)-1-butanone (NNK). Here we report that both CYP2A6 and CYP2A13 were inactivated during nicotine metabolism. Inactivation of both enzymes was dependent on NADPH and increased with time and concentration. Alternate substrates for CYP2A6 and CYP2A13 protected these enzymes from inactivation. Inactivation of CYP2A13 was irreversible upon extensive dialysis and seems to be mechanism-based. The K(I) of CYP2A13 inactivation by nicotine was 17 microM, the rate of inactivation, k(inact), was 0.1 min(-1), and the t(1/2) was 7 min. However, the loss in enzyme activity occurred after nicotine metabolism was complete, suggesting that a secondary or possible tertiary metabolite of nicotine may be responsible. [5-(3)H]Nicotine metabolism by CYP2A13 was monitored by radioflow high-pressure liquid chromatography during the course of enzyme inactivation; the major product was the Delta(1'(5'))iminium ion. However, cotinine was a significant metabolite even at short reaction times. The metabolism of the nicotine Delta(1'(5'))iminium ion to cotinine did not require the addition of aldehyde oxidase. CYP2A13 catalyzed this reaction as well as further metabolism of cotinine to 5'-hydroxycotinine, trans-3'-hydroxycotinine, and N-(hydroxymethyl)-norcotinine as enzyme inactivation occurred. Studies are on-going to identify the metabolite responsible for nicotine-mediated inactivation of CYP2A13.     

Sensitization of neuronal A2A adenosine receptors after persistent D2 dopamine receptor activation

Acute activation of Galpha(i/o)-coupled D2 dopamine receptors inhibits A2A adenosine receptor stimulation of adenylate cyclase. This antagonistic interaction between D2 dopamine and A2A adenosine receptors has been well documented; however, the effects of persistent activation of D2 dopamine receptors on subsequent A2A adenosine receptor signaling have not been explored. The present study investigated the effects of short-term (3-h) and long-term (18-h) activation of D2L dopamine receptors on subsequent A2A adenosine receptor stimulation of adenylate cyclase in CAD-D2L and NS20Y-D2L neuroblastoma cells. Short- and long-term activation of D2L dopamine receptors markedly increased 5'-N-methylcarboxamidoadenosine (MECA)-stimulated cyclic AMP accumulation 1.4-fold and 1.7-fold, respectively. D2L receptor-induced sensitization of A2A-stimulated cyclic AMP accumulation was blocked by the D2 antagonist spiperone and pertussis toxin pretreatment. In addition, persistent activation of A2A adenosine receptors resulted in 50% desensitization of subsequent MECA-stimulated cyclic AMP accumulation; however, MECA-induced desensitization of A2A adenosine receptors did not prevent completely quinpirole-induced sensitization of adenylate cyclase. These studies revealed a novel mode of regulation between D2L dopamine and A2A adenosine receptors and suggest a cooperative interaction in the regulation of cyclic AMP signaling.     

基底核中腺苷A_(2A)受体和多巴胺D_2受体调节睡眠-觉醒作用机制

越来越多的研究关注基底核(basal ganglia,BG)对睡眠-觉醒的调节作用,其中纹状体和苍白球可能是控制睡眠和觉醒的关键结构。腺苷A2A受体与多巴胺D2受体在基底核中均高度共表达,特别是在纹状体。腺苷是目前为止发现的最强的内源性促眠物质之一,可通过激活A1和A2A受体诱导睡眠。而多巴胺D2受体对于觉醒的维持有着重要作用。这些研究成果均提示基底核中A2A受体和D2受体调节睡眠-觉醒,腺苷作用于兴奋性的A2A受体,增加伏隔核中抑制性GABA能神经元活性,抑制主要觉醒系统,促进睡眠;抑制性多巴胺D2受体系统则发挥了相反的作用。本文综述基底核中腺苷A2A受体和多巴胺D2受体调节睡眠-觉醒机制。