Surface Modification of Biomimetic PLGA-(ASP-PEG) Matrix with RGD-Containing Peptide:a New Non-Viral Vector for Gene Transfer and Tissue Engineering

RGD-containing peptide （ K16-GRGDSPC） , characterized as non-viral gene vectors, was fabricated to modify the surface of PLGA-[ASP- PEG] matrix, which offered the foundation for gene transfer with porous matrix of gene activated later. Peptide was synthesized and matrix was executed into chips A, B and chip C. Chip C was regarded as control. Chips A and B were reacted with cross-linker. Then chip A was reacted with peptide. MS and HPLC were ased to detect the .14W and purity of peptide. Sulphur, existing on the surface of biomaterials, was detected by XPS. The purity of un-reacted peptide in residual solution was detected by a spectrophotometer. HPLC shows that the peptide purity was 94%- 95% , and MS shows that the MW was 2 741. 3307. XPS reveals that the binding energy of sulphur was 164 eV and the ratio of carbon to sulphur （C/S） was 99. 746 ：0. 1014 in reacted chip A. The binding energy of sulphur in reacted chip B was 164 eV and 162 eV, C/ S was 99.574：0.4255, aM there was no sulphur in chip C. Peptide was manufactured and linked to the surface of biomimetic and 3-D matrix, which offered the possibilities for gene transfer and tissue engineering with this new kind of non-viral gene vector.

MicroRNA-regulated viral vectors for gene therapy

Safe and effective gene therapy approaches require targeted tissue-specific transfer of a therapeutic transgene.Besides traditional approaches, such as transcriptional and transductional targeting, micro RNA-dependent posttranscriptional suppression of transgene expression has been emerging as powerful new technology to increase the specificity of vector-mediated transgene expression. Micro RNAs are small non-coding RNAs and often expressed in a tissue-, lineage-, activation- or differentiation-specific pattern. They typically regulate gene expression by binding to imperfectly complementary sequences in the 3' untranslated region(UTR) of the m RNA. To control exogenous transgene expression, tandem repeats of artificial micro RNA target sites are usually incorporated into the 3' UTR of the transgene expression cassette, leading to subsequent degradation of transgene m RNA in cel s expressing the corresponding micro RNA. This targeting strategy, first shown for lentiviral vectors in antigen presenting cells, has now been used for tissue-specific expression of vector-encoded therapeutic transgenes, to reduce immune response against the transgene, to control virus tropism for oncolytic virotherapy, to increase safety of live attenuated virus vaccines and to identify and select cell subsets for pluripotent stem cell therapies, respectively. This review provides an introduction into the technical mechanism underlying micro RNA-regulation, highlights new developments in this field and gives an overview of applications of micro RNA-regulated viral vectors for cardiac, suicide gene cancer and hematopoietic stem cell therapy, as well as for treatment of neurological and eye diseases.

Gene therapy for hemophilia B mediated by recombinant adeno-associated viral vector with hFIXR338A,a high catalytic activity mutation of human coagulation factor IX

A mutant human factor IX with arginine at 338 residual changed to alanine (hFIXR338A) by site-directed mutagenesis was introduced into AAV vectors, and a recombinant adeno-associ-ated viral vector containing hFIXR338A, prepared by rHSV/AAV hybrid helper virus system, was directly introduced to the hind leg muscle of factor IX knock out mice. The expression and the biological activity of human factor IX mutant, hFIXR338A, and the immune response against it in the treated mice were assayed and detected. The results showed that (i) the high-level expression of human factor IX mutant protein, hFIXR338A, has been detected in rAAV-hFIXR338A treated hemophilia B mice and lasted more than 15 weeks; (ii) the clotting activity of hFIXR338A in plasma is 34.2%± 5.23%, which is remarkably higher than that of (14.27%±3.4%) of wild type hFIX treated mice in the activated partial thromboplastin assay; (iii) immune response against factor IX R338A was absent, with no factor IX mutant protein (hFIXR338A) inhibitors development in the treated mice; and (iv) no local or systemic side-effects and toxicity associated with the gene transfer were found. It demonstrated the potential use of treating hemophilia B by recombinant adeho-associated viral vectors with mutant hFIXR338A gene, an alternative strategy for hemophilia B gene therapy to wild-type human factor IX.

A new can didate vaccine for human brucellosis based on influenza viral vectors:a preliminary investigation for the development of an immunization schedule in a guinea pig model

Background:A new candidate vector vaccine against human brucellosis based on recombinant influenza viral vectors(rIVV)subtypes H5N1 expressing Brucella outer membrane protein(Omp)16,L7/L12,Omp19or Cu-Zn SOD proteins has been developed.This paper presents the results of the study of protection of the vaccine using on guinea pigs,including various options of administering,dose and frequency.Provided data of the novel vaccine candidate will contribute to its further movement into the preclinical stage study.Methods:General states of guinea pigs was assessed based on behavior and dynamics of a guinea pig weight-gain test.The effectiveness of the new anti-brucellosis vector vaccine was determined by studying its protective effect after conjunctival,intranasal and sublingual administration in doses 10^(5) EID50,10^(6) EID_(50) and 10^(7) EID_(50) during prime and boost vaccinations of animals,followed by challenge with a virulent strain of B.melitensis 16 M infection.For sake of comparison,the commercial ft melitensis Rev.1 vaccine was used as a control.The protective properties of vaccines were assessed by quantitation of Brucella colonization in organs and tissues of infected animals and compared to the control groups.Results:It was observed a gradual increase in body weight of guinea pigs after prime and booster immunization with the vacci ne using conjunctival,intra nasal and subli ngual routes of administration,as well as after using various doses of vaccine.The most optimal way of using the vaccine has been established:double intranasal immunization of guinea pigs at a dose of 10^(6) EID50, which provides 80%protection of guinea pigs from B.melitensis 16 M infection(P<0.05),which is comparable to the results of the effectiv en ess of the commercial B.melitensis Rev.1 vacci ne.Conclusions:We developed effective human vaccine candidate against brucellosis and developed its immunization protocol in guinea pig model.We believe that because of these studies,the proposed vaccine has achieved the best level of protection,which in turn provides a basis for its further promotion.

Tailoring minimalist self-assembling peptides for localized viral vector aene deliverv

Viral vector gene delivery is a promising technique for the therapeutic administra- tion of proteins to damaged tissue for the improvement of regeneration outcomes in various disease settings including brain and spinal cord injury, as well as autoimmune diseases. Though promising results have been demonstrated, limitations of viral vectors, including spread of the virus to distant sites, neutralization by the host immune system, and low transduction efficiencies have stimulated the investigation of biomaterials as gene delivery vehicles for improved protein expression at an injury site. Here, we show how N- fluorenylmethyloxycarbonyl （Fmoc） self-assembling peptide （SAP） hydrogels, designed for tissue-specific central nervous system （CNS） applications via incorporation of the laminin peptide sequence isoleucine-lysine-valine-alanine- valine （IKVAV）, are effective as biocompatible, localized viral vector gene delivery vehicles in vivo. Through the addition of a C-terminal lysine （K） residue, we show that increased electrostatic interactions, provided by the additional amine side chain, allow effective immobilization of lentiviral vector particles, thereby limiting their activity exclusively to the site of injection and enabling focal gene delivery in vivo in a tissue-specific manner. When the C-terminal lysine was absent, no difference was observed between the number of transfected cells, the volume of tissue transfected, or the transfection efficiency with and without the Fmoc-SAP. Importantly, immobilization of the virus only affected transfection cell number and volume, with no impact observed on transfection efficiency. This hydrogel allows the sustained and targeted delivery of growth factors post injury. We have established Fmoc-SAPs as a versatile platform for enhanced biomaterial design for a range of tissue engineering applications.

Preparation of a recombinant adeno-associated viral vector with a mutation of human factor-Ⅸin large scale and its expression in vitro and in vivo

A series of adeno-associated viral vectors containing a mutation of human factor Ⅸ (hFⅨR338A) with different regulation elements were constructed and used to transduce cell lines. The plasmids and the stable transduction cell clones with high expression level of hFⅨR338A were obtained by selecting and optimizing, and then, the recombinant adeno-associated viral vector with hFⅨR338A was prepared via novel rHSV/AAV hybrid virus packaging system on a large scale, which contained the capsid protein genes. A method for producing rAAV-hFⅨR338A viral stocks on a large scale and higher titer was established, which can be used for industrial purpose. The titer of rAAV-hFⅨR338A was more than 1.25?012 particle/mL, and then, a mammalian cell line, C2C12 and the factor Ⅸ knock-out mice were transfected with the rAAV-hFⅨR338A in vitroand in vivo. The results show that the high-level expression of rAAV-hFⅨR338A was achieved in cell line and hemophilia B mice. It reached at (2551.32±92.14) ng·(106 cells)-1·(24h)-1 in C2C12 cell in vitro and had a peak concentration of 463.28 ng/mL in mice treated with rAAV-hFⅨR338A, which was as high as the expression of rAAV-hFⅨ-wt(2565.76?4.36) ng·(106 cells) -1·(24 h)-1 in C2C12 and453.92 ng/mL in the mice treated with rAAV-hFⅨ-wt) in vitro and in vivo, there is no any difference between two groups, but the clotting activity of hFⅨR338A is about 2.46 times higher than that of hFⅨ-wt. It was first reported that a mutation of human factor Ⅸ was used into gene therapyresearch for hemophilia B, meanwhile, a novel packagingsystem, rAAV/HSV was used for preparation of rAAV-hFⅨR338A on a large scale, which laid the foundation ofindustrial production for applying rAAV viral stocks to gene therapy clinical trial for hemophilia B mediated withrAAV-hFⅨ.

A Viral Expression Vector from Foxtail mosaic virus to Express Green Fluorescent Protein

[Objective]Foxtail mosaic virus(FoMV)infects gramineous and dicotyledonous plants.In this study,we sought to construct a viral vector based on FoMV to express exogenous proteins in plants.[Method]A recombinant viral expression vector was constructed by inserting the promotor of Potato virus X(PVX)and exogenous gene sequences into the 3’non-coding region of the FoMV coat protein gene.[Results]The plasmid pCB301-FoMV-CP-PVXprom-GFP expressed green fluorescent protein in inoculated Nicotiana benthamiana leaves.[Conclusion]A recombinant viral expression vector was constructed successfully.

Increasingβ-hexosaminidase A activity using genetically modified mesenchymal stem cells

GM2 gangliosidoses are a group of autosomal-recessive lysosomal storage disorde rs.These diseases result from a deficiency of lysosomal enzymeβ-hexosaminidase A(HexA),which is responsible for GM2 ganglioside degradation.HexA deficiency causes the accumulation of GM2-gangliosides mainly in the nervous system cells,leading to severe progressive neurodegeneration and neuroinflammation.To date,there is no treatment for these diseases.Cell-mediated gene therapy is considered a promising treatment for GM2 gangliosidoses.This study aimed to evaluate the ability of genetically modified mesenchymal stem cells(MSCs-HEXA-HEXB)to restore HexA deficiency in Tay-Sachs disease patient cells,as well as to analyze the functionality and biodistribution of MSCs in vivo.The effectiveness of HexA deficiency cross-correction was shown in mutant MSCs upon intera ction with MSCs-HEXA-HEXB.The results also showed that the MSCs-HEXA-HEXB express the functionally active HexA enzyme,detectable in vivo,and intravenous injection of the cells does not cause an immune response in animals.These data suggest that genetically modified mesenchymal stem cells have the potentials to treat GM2 gangliosidoses.

诺如病毒疫苗研究概况

诺如病毒(norovirus,NoV)是引发急性胃肠炎疾病的主要病原体之一。NoV易发生突变产生多种毒株,对人类健康造成严重威胁。由于缺乏成功的动物模型,抗NoV药物和疫苗的后续评价受到了限制,目前尚没有上市的疫苗用于NoV的预防。对NoV疫苗的研究进展进行了综述,重点阐述了病毒样颗粒(virus like particles,VLP)疫苗、病毒载体疫苗和基于P颗粒疫苗的研究现状和发展前景,以期为NoV疫苗的研发提供新思路。

动物疫病活载体疫苗研究进展

活载体疫苗是以细菌或病毒作为载体表达外源抗原和治疗因子的载体系统,具有安全性高、毒力返祖风险低、成本低,可诱导免疫机体产生高水平的体液免疫、细胞免疫或黏膜免疫等优点,是目前最具发展潜力的基因工程疫苗之一,在动物疫病防控领域应用较多。病毒载体包括DNA病毒(如腺病毒、腺相关病毒和痘病毒等)和RNA病毒(如新城疫病毒、流感病毒等);细菌载体包括减毒致病菌与非致病菌两类,主要包括乳酸菌、沙门氏菌、大肠杆菌等。活载体疫苗常用的抗原呈递策略有载体-宿主平衡致死系统、微生物表面展示系统。多种疫苗载体的开发及抗原呈递策略的选择,使得活载体疫苗的使用价值最大化。不同载体疫苗在预防疫病方面均有不同优缺点,应根据实际情况选择最优最适合的活载体疫苗。本文综述了动物疫病防控领域的病毒和细菌活载体疫苗研究进展及其抗原呈递方式,以期为活载体疫苗的进一步研究提供参考。

非洲猪瘟病毒F334L基因编码蛋白的原核表达及多克隆抗体制备

本研究通过将非洲猪瘟病毒(African swine fever virus,ASFV)的一种非结构蛋白编码基因F334L克隆至原核表达载体pCold-Ⅰ,完成重组表达质粒pCold-Ⅰ-ASFV-F334L的构建。将pCold-Ⅰ-ASFV-F334L转化受体菌感受态细胞,经1 mmol/L的IPTG诱导原核表达。SDS-PAGE和Western blot试验检测结果表明,F334L基因得到了良好的表达,将所得的F334L基因编码蛋白纯化后免疫小鼠,获得含多克隆抗体的血清。利用该抗体检测实验室构建并拯救的表达ASFV F334L基因编码蛋白的重组猪繁殖与呼吸综合征病毒rPRRSV-F334L,试验结果显示该多克隆抗体具有良好的反应原性和特异性,证明了ASFV F334L基因可在PRRSV活载体中稳定表达,为ASFV活载体疫苗的研发提供了材料。

鸭瘟病毒载体疫苗研究进展

疫苗接种是控制疫病的有效方法一,其中病毒载体疫苗以其转染效率高、外源基因表达水平高等优点成为当前疫苗的重要研究方向。鸭瘟病毒基因非常适合作为插入和表达其他病原体的外源抗原基因,并且随着CRISPR/Cas9技术、细菌人工染色体技术、同源重组技术等基因编辑技术的发展,鸭瘟病毒作为最有前途的载体被广泛应用于传染病疫苗研发。经试验验证,基于重组鸭瘟病毒载体的禽细菌病疫苗以及禽流感、鸭病毒性肝炎等多种病毒病疫苗均具有较好的免疫效果和安全性。本文综述了鸭瘟病毒作为疫苗载体的特点、鸭瘟病毒的基因编辑技术和鸭瘟病毒载体疫苗应用研究进展情况,以期为进一步研发鸭瘟病毒载体疫苗提供理论基础,同时也为新发传染病预防提供新策略。

基因治疗递送系统的研究新进展:遗传性视网膜疾病治疗的曙光

遗传性视网膜疾病是多种先天性视网膜神经退行性疾病的总称,临床上以夜盲、进行性视野缩小、视力下降甚至失明为特点,具有多种遗传形式。由于其病变的根源在于基因突变,通过基因治疗,即利用外源性核苷酸替换或沉默基因缺陷细胞内的致病基因,使细胞表达正确的蛋白质,恢复细胞的功能,就有可能治愈疾病。同时,眼睛具有免疫“豁免”特性,是实现基因治疗的理想器官。为了完成遗传物质的修正,治疗性核苷酸需要进入细胞内发挥作用,携带健康基因的载体递送系统是实现这一过程的有利工具。该文重点总结了包括病毒载体和非病毒载体在内的遗传性视网膜疾病基因治疗递送系统的研究进展及面临的问题。

病毒载体疫苗研究进展

近十年来,中东呼吸综合征、埃博拉出血热、寨卡病毒感染、新型冠状病毒肺炎等重大传染性疾病疫情相继出现,对疫苗的快速研发提出重大挑战。其中病毒载体疫苗是新型疫苗研发的重要形式,它可以通过雾化吸入或口服等方式进行无创免疫,在没有佐剂的情况下发挥免疫作用,同时诱导体液、细胞和黏膜免疫反应,具有良好的免疫原性和安全性。随着对病毒基因组和结构蛋白等元件认识的不断深入,利用合成生物学研究思路系统设计、改造病毒载体,从而赋予重组病毒载体疫苗高滴度生产、高安全性和高免疫原性等生物学特征,对疫苗研发具有重要指导意义。本文综述了复制型、非复制型等病毒载体疫苗研发策略,以及具有临床应用价值的疫苗病毒载体,如腺病毒载体、痘病毒载体、水疱性口炎病毒载体等,希望对利用合成生物学进行新型病毒载体疫苗的研发提供一定的参考。未来,病毒载体疫苗必将向着更高的安全性、更强的保护性、更好的依从性、更低的生产成本等方向迭代发展。

合成生物学在基于微生物载体肿瘤疫苗设计中的应用

合成生物学有望创造具备独特优势的抗肿瘤微生物疫苗,合成生物学改造的微生物更能适应肿瘤微环境并在其中富集与增殖,削弱或者逆转免疫抑制细胞的功能,并增强肿瘤抗原的呈递,诱发多种先天与适应性抗肿瘤免疫反应,所以合成生物学已成为肿瘤疫苗研究的重要工具。本文总结了合成生物学在细菌和病毒载体肿瘤疫苗开发中的几个关键应用,其中包括减弱微生物载体毒性的方法,例如去除、失活或修改其致病基因等。讨论了增强它们在肿瘤组织中的趋向性和适应性的策略,如改变它们的细胞入侵分子或引入环境控制的基因表达系统等;也讨论了降低全身毒性的方法。为了充分利用微生物复制引起的肿瘤微环境改变的潜力,多种合成生物学手段被用于改造微生物载体,这些方法包括将外源基因引入微生物基因组,使其生产诸如细胞因子、趋化因子或单克隆抗体等分子,这些分子可以增强先天和适应性免疫细胞的招募和激活,促进肿瘤细胞免疫原性死亡,并增强肿瘤相关抗原的呈递。此外,还探讨了将肿瘤抗原引入载体中的方法,例如不同的装载方式、位置和释放机制。开发微生物载体肿瘤疫苗存在重大挑战,包括安全性问题、抗载体免疫与抗肿瘤免疫的复杂关系和肿瘤生物学的复杂性,克服这些困难将成为未来研究的重要方向。

结核病病毒载体疫苗研究进展

结核病(TB)由结核分枝杆菌感染引起,其发病率和死亡率在传染性疾病中均居于前列,而疫苗是有效控制TB的重要因素。鉴于卡介苗(BCG)对成年人TB预防效果有限,新型TB疫苗(尤其是病毒载体疫苗)意义重大。该文拟对TB病毒载体疫苗的类型、效力及其研究进展做一综述。

病毒类基因工程疫苗研究进展

疫苗接种被认为是控制病原体和预防人类以及动物疾病最有效的方法之一.近年来由于病毒性疾病来势汹汹,传统疫苗如灭活或减毒活疫苗的局限性及潜在问题日益突显,而基因工程技术的进步使得疫苗设计和研发得以改进,由此衍生的病毒类基因工程疫苗作为下一代疫苗越来越受到研究者的高度关注.通过病毒类基因工程疫苗的类型,重点介绍不同疫苗的开发原理、特点及用途,探讨其应用前景和发展趋势,旨在为新发病毒类疾病疫苗的研发提供参考.

纳米粒子在骨组织工程化基因修饰治疗中的应用

背景:传统的骨组织工程技术治疗临界骨缺损存在成骨效率低、安全性差等问题。而以非病毒纳米粒子为基因载体构建的基因强化型骨组织工程移植物,具有更高的成骨效率和安全性,引起了国内外学者的广泛关注和研究。目的:对当前国内外有关纳米粒子在组织工程成骨基因治疗研究中取得的新技术、新方法以及面临的挑战等进行综述,旨在为纳米粒子介导的骨组织工程基因治疗研究提供参考。方法:第一作者在Pub Med、Web of Science和中国知网数据库上进行文献检索,并以“Bone defect repair,Bone tissue engineering,Gene delivery,Nanoparticles,Non-viral gene vector,Sustained release technology,Sequential release,Targeted delivery”作为英文检索词,以“骨缺损修复,骨组织工程,基因递送,纳米粒子,非病毒基因载体,缓释技术,序贯释放,靶向递送”作为中文检索词,最终纳入84篇文献进行总结。结果与结论:(1)在骨缺损愈合的各个生理阶段进行针对性的基因递送可以显著增强骨修复效果。在早期炎症阶段,通过纳米粒子递送抗炎基因来调节炎症反应,可以为后续骨愈合奠定基础;在血管新生期,向局部递送促血管化基因有助于形成高度组织化、可灌注的血管系统,加快骨愈合速度;随着血管化的进行,骨骼的神经再支配也开始发生,此时递送促神经再生的功能性基因有利于促进神经化骨再生;在成骨阶段,通过构建纳米粒子-成骨基因复合物,可以直接提升支架及体内新骨形成的效率。(2)各种有机、无机纳米颗粒、金属有机框架和外泌体等非病毒纳米载体,在骨组织工程基因治疗中具有巨大的潜力,这些纳米基因载体各有其独特的优势和不足,因此在实际应用时,需要根据基因转染效率、生物安全性和成骨特性等因素选择最合适的类型。(3)为了全面提升递送基因的效果,目前主要通过对纳米载体进行各种功能设计来增强基因转染效率,包括增强缓释性和多基因递送序贯性等时间调控能力、增强对骨组织和成骨相关细胞的空间靶向能力、增强跨膜运输效率和细胞核靶向能力等全过程调控手段。(4)未来要进一步推动纳米粒子介导的骨组织工程基因治疗在临床上的应用,还需要克服诸多技术挑战,包括提高有机纳米基因载体的基因转染效率、降低无机纳米载体的生物安全性风险、优化新型纳米载体的生产工艺以及促进其它生理过程与成骨交互作用等,这些问题也是未来骨组织工程基因治疗的研究热点和潮流。

Use of PEI-coated Magnetic Iron Oxide Nanoparticles as Gene Vectors

Summary: To evaluate the feasibility of using polyethyleneimine (PEI) coated magnetic iron oxide nanoparticles (polyMAG-1000) as gene vectors. The surface characteristics of the nanoparticles were observed with scanning electron microscopy. The ability of the nanoparticles to combine with and protect DNA was investigated at different PH values after polyMAG-1000 and DNA were combined in different ratios. The nanoparticles were tested as gene vectors with in vitro transfection models. Under the scanning electron microscope the nanoparticles were about 100 nm in diameter. The nanoparticles could bind and condense DNA under acid, neutral and alkaline conditions, and they could transfer genes into cells and express green fluorescent proteins (GFP). The transfection efficiency was highest (51 %) when the ratio of nanoparticles to DNA was 1:1 (v:w). In that ratio, the difference in transfection efficiency was marked depending on whether a magnetic field was present or not: about 10 % when it was absent but 51 % when it was present. The magnetic iron oxide nanoparticles coated with PEI may potentially be used as gene vectors.

病毒载体遗传毒性评价方法研究进展

随着基因治疗产品逐渐进入市场,迫切需要建立病毒载体介导的遗传毒性评价方法。目前应用广泛的病毒载体主要有2种:慢病毒载体和腺相关病毒载体。慢病毒载体能够稳定整合到宿主基因组中;而腺相关病毒载体基因组在宿主细胞核中主要以附加体形式存在,仍能以低频率随机整合到宿主细胞基因组中,其整合方式包括随机整合和靶向整合。本文对已有的病毒载体介导的遗传毒性评价方法,包括脱靶修饰的全基因组分析、整合位点分析、核型分析和评估细胞转化潜力试验等进行综述,并对建立准确快速的病毒载体介导的遗传毒性的评价体系予以展望,以期为进一步完善和研发新的病毒载体遗传毒性评价方法提供参考。