Adenovirus Biology,Recombinant Adenovirus,and Adenovirus Usage in Gene Therapy

Gene therapy is currently in the public spotlight. Several gene therapy products, including oncolytic virus (OV), which predominantly replicates in and kills cancer cells, and COVID-19 vaccines have recently been commercialized. Recombinant adenoviruses, including replication-defective adenoviral vector and conditionally replicating adenovirus (CRA; oncolytic adenovirus), have been extensively studied and used in clinical trials for cancer and vaccines. Here, we review the biology of wild-type adenoviruses, the methodological principle for constructing recombinant adenoviruses, therapeutic applications of recombinant adenoviruses, and new technologies in pluripotent stem cell (PSC)-based regenerative medicine. Moreover, this article describes the technology platform for efficient construction of diverse “CRAs that can specifically target tumors with multiple factors” (m-CRAs). This technology allows for modification of four parts in the adenoviral E1 region and the subsequent insertion of a therapeutic gene and promoter to enhance cancer-specific viral replication (i.e., safety) as well as therapeutic effects. The screening study using the m-CRA technology successfully identified survivin-responsive m-CRA (Surv.m-CRA) as among the best m-CRAs, and clinical trials of Surv.m-CRA are underway for patients with cancer. This article also describes new recombinant adenovirus-based technologies for solving issues in PSC-based regenerative medicine.     

DNA plasmid that codes for human Bcl-2 gene preserves axotomized Clarke's nucleus neurons and reduces atrophy after spinal cord hemisection in adult rats

Spinal cord injury in adult mammals causes atrophy or death of some axotomized neurons. The product of the antiapoptotic gene Bcl-2 prevents neuron death in vivo. We delivered Bcl-2 by intraspinal injection of a DNA plasmid encoding this gene to determine if axotomized neurons destined to undergo retrograde death could be rescued. Axons of the right side Clarke's Nucleus (CN) were cut unilaterally in adult Sprague-Dawley rats by T8 hemisection, leaving the contralateral (left) CN as an intact control. Two months postoperatively, there was ∼35% loss of total CN neurons in the right L1 segment. Only 15% of large CN neurons (>400 μm²), whose axons project to the cerebellum, survived—indicating atrophy and/or death of 85% of these cells. We injected a DNA plasmid encoding the human Bcl-2 gene and the bacterial reporter gene LacZ, which was complexed with cationic lipids, into the right side of segment T8 of the normal spinal cord, or just caudal to the hemisection site. The reporter gene was expressed in the perikarya of right CN neurons at L1 for up to 7 days, but not 14 days. Two months following T8 hemisection and Bcl-2/LacZ DNA injection, there was no significant loss of CN neurons ipsilateral to the lesion. Surprisingly, 61% of large neurons survived, indicating partial protection from atrophy. In contrast, a DNA plasmid that codes for the LacZ reporter gene, but not Bcl-2, did not prevent CN neuron death or atrophy. Administration of the Bcl-2 gene in adult rats and its expression in these CNS neurons prevents retrograde cell death, and also minimizes atrophy. These results may serve as the basis for developing novel gene therapy strategies for patients with spinal cord injury. J. Comp. Neurol. 404:159–171, 1999. © 1999 Wiley-Liss, Inc.     

Potential Mosquito Vectors for Shuni Virus,South Africa, 2014–2018

Shuni virus is associated with neurologic and febrile illness in animals and humans. To determine potential vectors, we collected mosquitoes in South Africa and detected the virus in species of the genera Mansonia, Culex, Aedes, and Anopheles. These mosquitoes may be associated with Shuni virus outbreaks in Africa and emergence in other regions.     

人PDX-1基因真核表达载体的构建及表达

目的构建人胰十二指肠同源盒(PDX-1)基因的真核表达载体,观察其在NIH3T3细胞中的表达。方法以人胰岛细胞瘤cDNA为模板,采用聚合酶链式反应(PCR)扩增PDX-1基因编码区的全部序列,克隆入真核细胞表达载体pcDNA3.1中,经限制性内切酶双酶切及DNA序列分析鉴定目的基因。序列正确的重组质粒用脂质体转染NIH3T3细胞,Western blot观察基因表达情况。结果PCR扩增的特异性片段长度为852 bp,以此构建的重组质粒pcDNA3.1-PDX-1,经BamHⅠ和EcoRⅠ双酶切后显示5.5 kb和850 bp左右的两条片段,测序结果与GenBank中的人PDX-1基因cDNA(GenBank序列号NM_000209)序列一致。证明PDX-1基因已成功克隆到了真核细胞表达载体pcDNA3.1中。Western blot证实pcDNA3.1-PDX-1转染NIH3T3细胞24 h后有PDX-1的表达。结论成功构建了pcDNA3.1-PDX-1重组真核表达载体,并在NIH3T3细胞中表达。     

人截断型LBP基因的克隆及其杆状病毒表达载体的构建

目的 构建人N端截断型脂多糖结合蛋白（tLBP)基因的杆状病毒表达载体,为后续的蛋白表达及其抗内毒素保护作用研究奠定基础。方法 采用PCR技术从人全长LBP基因cDNA中扩增长度为695bp的基因片段,经pGEM-T载体亚克隆筛选和序列分析后,应用Bac-To-Bac杆状病毒表达系统,基因重组和外源基因转座分别构建转移质粒pFASTBACtLBP和穿梭质粒pBac-midtLBP。结果 经PCR、琼脂糖凝胶电泳、酶切分析及序列测定,所克隆的基因片段为700bp左右的tLBP,并证实其目的基因重组载体发生了特异转座和病毒重组。结论 本实验成功克隆了tLBP目的基因片段并构建其杆状病毒表达载体。     

HGF基因对大鼠血管内皮细胞增殖的作用

目的构建肝细胞生长因子(HGF)真核细胞表达质粒pEGFP-HGF-C1,探讨HGF对大鼠血管内皮细胞(VECs)的作用。方法通过亚克隆技术,构建含有人HGF cDNA全长的真核细胞表达质粒pEGFP-HGF-C1并测序;向大鼠原代骨骼肌细胞转染质粒pEGFP-HGF-C1,测定转染效率;ELISA法测定细胞上清液中HGF蛋白表达浓度;MTT法测定HGF表达产物对大鼠VECs促增殖作用。结果成功构建正向表达HGF的真核细胞表达质粒pEGFP-HGF-C1,该质粒可有效转染原代培养的骨骼肌细胞并表达HGF,且其表达产物HGF对大鼠VECs的促增殖作用具有量效和时效关系(P<0.05或P<0.01)。结论成功构建的真核表达质粒pEGFP-HGF-C1能有效转染大鼠骨骼肌细胞,分泌的HGF对大鼠VECs有促增殖作用。     

巨噬细胞炎性蛋白4的非融合表达载体的构建和表达

目的探索如何抑制嗜酸性粒细胞的趋化作用,选择β-趋化因子巨噬细胞炎性蛋白4(MIP4)的突变体(Met-MIP4)作为趋化因子受体3的拮抗剂,将Met-MIP4基因在原核细胞中进行非融合表达. 方法设计MIP4基因的PCR引物并进行氨基酸突变,将MIP4 N末端的丙氨酸突变为蛋氨酸.以正常人肺cDNA文库为模板,PCR方法获取Met-MIP4基因.克隆入载体pUC19,测序验证序列已得到突变.将正确的基因插入到非融合表达载体pBV220中进行表达.结果 PCR产物为220 bp左右的片段,连接入pUC19质粒后测序验证获得正确突变.构建的pBV220非融合表达载体在大肠杆菌DH5-α中表达,经Tricine-SDS-PAGE凝胶电泳显示有大小约8×103的非融合蛋白表达.结论成功突变并克隆了β-趋化因子MIP4基因.Tricine-SDS-PAGE表明,非融合的Met-MIP4突变体已得到表达,为进一步研究其对哮喘的生物治疗奠定了基础.     

细胞间粘附分子—1反义DNA体外对内皮细胞细胞间粘附分子—1？…

目的：研究细胞间粘附分子－１（ＩＣＡＭ－１）的 ＤＮＡ对内皮细胞ＩＣＡＭ－１表达的抑制作用。方法：构建ＩＣＡＭ－１反义ＤＮＡ载体,用脂质体转染内皮细胞,ＴＮＦα刺激后,流式细胞术检测转染细胞表面ＩＣＡＭ－１蛋白的表达。结果：酶切鉴定证明,１．４ｋｂ的ＩＣＡＭ－１ＤＮＡ片段后向连接到ｐｃＤＮＡ３表达载体,;流式细胞术检测显示,正常细胞加ＴＮＦα刺激后,表面ＩＣＡＭ－１表达明显升高,转洒细胞加ＴＮＦα     

多发性内分泌腺瘤病1型患者血液细胞来源特异性诱导多能干细胞的建立

目的:建立多发性内分泌腺瘤病1型(multiple endocrine neoplasia 1,MEN1)患者血液细胞来源的特异性诱导多能干细胞(induced pluripotent stem cells,iPSCs)模型.方法:将表达Oct4、Sox2、Lin28、L-Myc和Klf4转录因子的oriP/EBNA1附着体电转染MEN1患者血液细胞使其重编程获得iPSCs,并通过碱性磷酸酶染色、核型鉴定、基因测序、RT-PCR反应、畸胎瘤形成实验及类胚体形成实验检测其特性.结果:获得的iPSCs碱性磷酸酶染色呈阳性,核型正常,测序结果显示在其第9号外显子存在c.1288 G>T位点突变,表达干细胞多能性基因Sox2、Oct4、Nanog和Klf4和Lin28,体内畸胎瘤形成实验可分化为内、中、外三胚层细胞,体外可形成类胚体.结论:成功获得携带第9号外显子c.1288 G>T位点突变的MEN1患者血液细胞来源的特异性iPSCs,为后续机制研究奠定基础.     

pLXSN-EGFP逆转录病毒载体的构建及体内外表达的研究

目的构建携带有绿色荧光蛋白(GFP)基因的逆转录病毒载体,观察该报告基因在动物体内外表达情况以及对靶细胞生物特性的影响。方法以质粒pEGFP-C1为模板进行PCR反应,获得增强型绿色荧光蛋白(EGFP)基因片段,定向插入逆转录病毒载体pLXSN获得重组逆转录病毒载体pLXSN-EGFP,转染PA317包装细胞后收集具有感染能力的病毒颗粒,转染人多型性脑胶质瘤细胞SW038-C2,通过荧光显微镜和流式细胞仪观察EGFP作为报告基因在体内外的表达情况以及对靶细胞生物特性的影响。结果成功克隆携带有EGFP基因的逆转录病毒载体,该载体经包装细胞包装后可有效转染人多型性脑胶质瘤细胞SW038-C2并在体内外稳定表达,对靶细胞及其所成肿瘤的生长无抑制。高表达GFP的靶细胞形态变得细长,FACS检测约有98%的细胞表达GFP,体外培养6个月荧光强度没有明显的衰减,而低表达GFP的靶细胞形态无变化,FACS检测有30.7%细胞表达GFP。结论该载体可在体内外成功表达,对靶细胞的生长无明显抑制,高表达GFP的靶细胞有一定形态上的变化;使用GFP作为报告基因,检测到的病毒载体转染率比实际偏低。