聚乙烯亚胺用作基因转染的研究进展

 基因载体问题以及与载体相关的免疫反应、细胞毒性和安全性等问题，是基因治疗领域亟待解决的关键问题之一。聚乙烯亚胺（PEI）是阳离子聚合物非病毒载体的典型代表^[1]，是一种很早便为人所知并予以应用的有机大分子。目前，以 PEI 阳离子聚合物与 DNA 形成的 PEI/DNA 复合物已成为非病毒基因载体的研究热点。本文就近年来这方面的研究进展作简要综述。 1 PEI的特性 PEI 每 3 个原子中有 1 个胺基原子，使其具有较高正电荷密度。根据 pH 与质子作用之间的对应关系可得出：自由 PEI 的结构在生理条件下有 1/6 至 1/5 胺基发生质子化反应，从而使溶酶体肿胀破裂，从而起到“质子海绵”作用，使 PEI/DNA 复合物得以释放入胞质，很大程度上减少了 DNA 在吞噬泡内富集并进而被降解的作用，因而可以提高转染效率^[2]。     

Polyethyleneimine and quaternized ammonium polyethyleneimine: the versatile materials for combating bacteria and biofilms

Abstract

Bacterial infection has become a serious clinical concern due to the emergence of drug-resistance and biofilm formation. Therefore, it is in great demand to develop efficient antimicrobial agents to treat bacterial infection without using antibiotics. Herein, we successfully prepared four quaternized ammonium PEI (QPEI: PEI₁₂₀₀-C2, PEI₁₂₀₀-C4, PEI₁₂₀₀-C6 and PEI₁₂₀₀-C8) using the commercial available PEI₁₂₀₀. Both PEI and four QPEI presented broad-spectrum antimicrobial activity against Gram-negative bacteria (E. coli, and P. aeruginosa) and Gram-positive bacteria (B. amyloliquefaciens and S. aureus), especially PEI₁₂₀₀-C6 showed the strongest antimicrobial activity with good biocompatibility at the MIC concentrations. Besides, PEI₁₂₀₀-C6 showed 4-16-fold better antibacterial effect than PEI₁₂₀₀, and fluorescent microscope imaging demonstrated that both of them could efficiently eradicate biofilms formed by four bacterial strains in vitro. As the accessible broad-spectrum antibacterial agents, PEI₁₂₀₀ and PEI₁₂₀₀-C6 are significant candidates to treat bacterial infections or eradicate biofilms on indwelling medical devices.     

聚乙烯亚胺-蛋白纳米复合体转染蛋白进入骨髓间充质干细胞的应用研究

目的:探索纳米材料聚乙烯亚胺(PEI)携载不同分子量的蛋白质转染进人骨髓间充质干细胞(h BMSCs)的作用及优化其最佳配比条件。方法:利用物理化学作用构建6组PEI-DNase I(DNA酶I)复合体,运用激光散射技术初步摸索其最佳摩尔比,用透射电镜直观复原纳米-蛋白复合体外貌;同时,原代分离培养健康人的骨髓间充质干细胞并进行体外扩增,通过构建成功的4组PEI-GFP(绿色荧光蛋白)纳米蛋白复合体对h BMSCs进行转染,共聚焦荧光显微镜下观察荧光表达情况,再通过MTT法检测该复合体对细胞增殖的毒性影响,并用β-半乳糖苷酶实验验证其转入蛋白的活性表现。结果:当PEI与蛋白质的摩尔比为4∶1时,形成的复合体转染效率最高,β-半乳糖苷酶实验细胞染色变蓝。结论:PEI能与蛋白质形成纳米复合体,并能转染多种蛋白质进入人骨髓间充质干细胞,所转染的蛋白质分子仍具有活性,为细胞重编程技术提供了新途径。     

聚乙烯亚胺非病毒基因载体结构修饰研究进展

聚乙烯亚胺（PEI）作为最经典的非病毒基因载体之一,由于其高转染效率,在基因递送领域受到极大的关注,但其毒性限制了聚乙烯亚胺的应用。本文综述了对聚乙烯亚胺进行不同的结构修饰,如多糖修饰、PEG修饰和低分子聚乙烯亚胺衍生物等,以实现在不显著降低转染效率的前提下减少细胞毒性。     

Lipid based nanocarriers: a translational perspective

Over the recent couple of decades, pharmaceutical field has embarked most phenomenal noteworthy achievements in the field of medications as well as drug delivery. The rise of Nanotechnology in this field has reformed the existing drug delivery for targeting, diagnostic, remedial applications and patient monitoring. The convincing usage of nanotechnology in the conveyance of medications that prompts an extension of novel lipid-based nanocarriers and non-liposomal systems has been discussed. Present review deals with the late advances and updates in lipidic nanocarriers, their formulation strategies, challenging aspects, stability profile, clinical applications alongside commercially available products and products under clinical trials. This exploration may give a complete idea viewing the lipid based nanocarriers as a promising choice for the formulation of pharmaceutical products, the challenges looked by the translational process of lipid-based nanocarriers and the combating methodologies to guarantee the headway of these nanocarriers from bench to bedside.     

Augmented cellular trafficking and endosomal escape of porous silicon nanoparticles via zwitterionic bilayer polymer surface engineering

The development of a stable vehicle with low toxicity, high cellular internalization, efficient endosomal escape, and optimal drug release profile is a key bottleneck in nanomedicine. To overcome all these problems, we have developed a successful layer-by-layer method to covalently conjugate polyethyleneimine (PEI) and poly(methyl vinyl ether-co-maleic acid) (PMVE-MA) copolymer on the surface of undecylenic acid functionalized thermally hydrocarbonized porous silicon nanoparticles (UnTHCPSi NPs), forming a bilayer zwitterionic nanocomposite containing free positive charge groups of hyper-branched PEI disguised by the PMVE-MA polymer. The surface smoothness, charge and hydrophilicity of the developed NPs considerably improved the colloidal and plasma stabilities via enhanced suspensibility and charge repulsion. Furthermore, despite the surface negative charge of the bilayer polymer-conjugated NPs, the cellular trafficking and endosomal escape were significantly increased in both MDA-MB-231 and MCF-7 breast cancer cells. Remarkably, we also showed that the conjugation of surface free amine groups of the highly toxic UnTHCPSi-PEI (Un-P) NPs to the carboxylic groups of PMVE-MA renders acceptable safety features to the system and preserves the endosomal escape properties via proton sponge mechanism of the free available amine groups located inside the hyper-branched PEI layer. Moreover, the double layer protection not only controlled the aggregation of the NPs and reduced the toxicity, but also sustained the drug release of an anticancer drug, methotrexate, with further improved cytotoxicity profile of the drug-loaded particles. These results provide a proof-of-concept evidence that such zwitterionic polymer-based PSi nanocomposites can be extensively used as a promising candidate for cytosolic drug delivery.     

泊洛沙姆407修饰对聚乙烯亚胺的毒性和转染性质的影响

目的:考察泊洛沙姆407修饰对聚乙烯亚胺(PEI)的毒性和转染性质的影响.方法:使用琥珀酰亚胺碳酸脂法将P407连接在PEI的氨基上,得到新聚合物,通过1H-NMR确定新聚合物的结构,将该聚合物与DNA形成复合物,测定复合物的zeta电位,MTT法考察复合物的细胞毒性,使用质粒pGL3-lus作为报告基因,测定虫荧光素酶活性评价复合物对Hela细胞的转染效率.结果:1H-NMR结果表明合成的聚合物具有较高的纯度.复合物的Zeta电位随氮/磷比(N/P)值的增加而增高.复合物的细胞毒性随着N/P值的增加而增大,新聚合物其细胞毒性显著低于未修饰的PEI.新聚合物在高N/P值时仍能保持较高的转染效率.结论:泊洛沙姆407修饰的PEI可以作为一种有效的非病毒基因栽体.     

水溶性脂聚体介导NR2B siRNA治疗神经病理性痛的实验研究

目的 探讨水溶性脂聚体(WSLP)介导含2B亚基的N-甲基-D-天冬氨酸受体小干扰RNA(NR2B siRNA)治疗大鼠神经病理性痛的可行性.方法 健康雄性SD大鼠100只,周龄6周,体重180～200 g,采用随机数字表法,将大鼠随机分为5组(n=20):对照组(C组)、假手术组(S组)、神经病理性痛组(NP组)、WSLP-NR2B siRNA组(W组)、WSLP-阴性对照NR2B siRNA(WN组).采用坐骨神经分支部分结扎法制备大鼠神经病理性痛模型.C组不予任何处理;S组仅暴露坐骨神经,不牵拉和损伤神经;NP组于制备模型后即刻鞘内注射生理盐水20μl;W组和WN组于制备模型后即刻分别鞘内注射相应的siRNA 20μl.于模型制备前1 d及制备后3、7、14和21 d时测定机械缩足反应阈值(MWT)及热缩足反应持续时间(TWD),模型制备后3 d,痛阈测定结束后,每组取10只大鼠,取L4-6节段背根神经节,测定NR2B mRNA及其蛋白的表达水平.结果 与S组比较,NP组、W组和WN组MWT降低,TWD延长,NR2B mRNA及其蛋白表达上调(P＜0.05或0.01),C组上述指标差异无统计学意义(P＞0.05);与NP组比较,W组MWT升高,TWD缩短,NR2B mRNA及其蛋白表达下调(P＜0.01),WN组上述指标差异无统计学意义(P＞0.05).结论 WSLP不仅成功介导NR2B siRNA,抑制NR2B的表达,还可减轻大鼠神经病理性痛.

Abstract：

Objective To investigate the feasibility of NR2B small interference RNA(NR2B siRNA)carried by water-soluble lipopolymer(WSLP)for treatment of neuropathic pain in rats.Methods One hundred healthy male SD rats weighing 180-200 g were randomly divided into 5 groups(n=20 each):normal control group (group C),sham operation group(group S),neuropathic pain group(group NP),group WSLP-NR2B siRNA (group W)and group WSLP-negative NR2B siRNA(group WN).Neuropathic pain was induced by partial ligation of sciatic nenre.WSLP-NR2B siRNA complex was formed by binding WSLP and NR2B siRNA.Normal saline.WSLP-NR2B siRNA complex and WSLP-negative NR2B siRNA 20μl were injected intrathecally after operation in NP,W and WN groups respectively.Mechanical withdrawal threshold(MWT)and thermal withdrawal duration (TWD)were measured before(baseline)and at 3,7,14 and 21 days after operation.Ten animals in each group were sacrificed on the 3rd day after operation and the lumbar segment(L4-6)of the dorsal root ganglia was removed for determination of the expression of NR2B mRNA and protein using RT-PCR and Western blot analysis.Results Sciatic nerve ligation significantly decreased MWT and prolonged TWD and increased NR2B mRNA and protein expression in group NP as compared with group C.WSLP-NR2B siRNA complex significantly reduced sciatic nerve ligation-induced hyperalgesia and decreased NR2B mRNA and protein expression in group W as compared with group NP.Conclusion WSLP not only mediates NR2B siRNA successfully and inhibits the expression of NR2B,but also reduces neuropathic pain in rats.     

半乳糖受体介导的PCNA反义核酸提高肝癌细胞对化疗药物的敏感性

目的　研究半乳糖(galactose ,Gal) -聚乙烯亚胺(polyethyleneimine ,PEI)介导的增殖细胞核抗原(pro liferatingcellnuclearantigen ,PCNA)反义核酸(antisenseoligdeoxynucleotides ,ASODN)分别与3种常用化疗药物5 -氟尿嘧啶(5 -fluorouracil,5 -FU) ,顺铂(cis-Diamminedichloroplatinum ,DDP) ,羟喜树碱(hydroxyicamptothecine ,HCPT)联合作用于人肝癌Bel- 74 0 2细胞,观察它们对细胞增殖的抑制作用。方法　将Gal-PEI与反义核酸形成交联复合物Gal-PEI-ASODN ,用CCK - 8细胞计数试剂盒检测单纯使用化疗药物以及联合0 0 3μmol/LASODN或0 0 3μmol/LGal-PEI-ASODN对Bel- 74 0 2细胞增殖的抑制作用,并分别计算抑制率和IC50 。结果　单纯使用5 -FU ,DDP ,HCPT作用于Bel- 74 0 2细胞4 8h ,其IC50 分别为16 15 ,1 88,0 31μg/ml;ASODN与上述药物联合使用其IC50 分别为12 5 9,1 71,0 2 7μg/ml,将Bel- 74 0 2细胞对化疗药物的敏感性分别提高到单用化疗药物的1 2 8,1 10 ,1 15倍;Gal-PEI-ASODN与上述药物联合使用其IC50 分别为0 5 1,0 90 ,0 10 μg/ml,将Bel- 74 0 2细胞对化疗药物的敏感性分别提高到单用化疗药物的31 6 7,2 0 9,3 10倍。金正均Q值法分析表明:5 -FU与Gal-PEI-ASODN联合使用,表现为协     

Using drug-excipient interactions for siRNA delivery

SiRNA is the trigger of RNA interference, a mechanism discovered in the late 1990s. To release the therapeutic potential of this versatile but large and fragile molecule, excipients are used which either interact by electrostatic interaction, passively encapsulate siRNA or are covalently attached to enable specific and safe delivery of the drug substance. Controlling the delicate balance between protective complexation and release of siRNA at the right point and time is done by understanding excipients-siRNA interactions. These can be lipids, polymers such as PEI, PLGA, Chitosans, Cyclodextrins, as well as aptamers and peptides. This review describes the mechanisms of interaction of the most commonly used siRNA delivery vehicles, and looks at the results of their clinical and preclinical studies.