siRNA非病毒递送载体的研究现状

RNA干扰(RNA interference,RNAi)是近年发展起来的一种新技术。RNAi是指通过外源性或内源性的双链RNA在体内诱导靶基因mRNA产生特异性降解,进而引起不同水平的基因沉默。RNAi已经用于肿瘤、病毒感染、乙型肝炎等多种疾病的治疗。小干扰RNA(siRNA)是RNAi的效应分子,可在体内诱导RNAi效应。但是裸siRNA在体内容易被核酶(RNase)降解,且半衰期短,转染效率低。因此,siRNA需要借助递送载体进入细胞发挥治疗作用。病毒载体在基因治疗中有潜在的免疫原性、致突变等副作用。所以,非病毒载体成为当前的研究热点。本文对siRNA非病毒递送载体的研究现状进行了综述。     

siRNA体内递送研究进展

RNA干扰(RNA interference,RNAi),是一种在动植物中存在的通过双链RNA诱导同源特异性序列转录后基因沉默的过程。虽然小干扰RNA (siRNA) 较单链反义寡核苷酸显示出更好的稳定性与基因沉默效果,但是作为新型的基因治疗药物,靶向递送siRNA是药物进入临床应用最主要的环节,siRNA体内有效作用发挥的关键在于它在体内能否高效递送至靶细胞并与靶基因结合。目前研究主要集中在siRNA的修饰方式与递送载体研究,以提高其体内的稳定性与靶向性。文中主要综述了siRNA的体内靶向递送障碍以及近几年siRNA非病毒递送载体脂质体、阳离子多聚物、纳米粒、胶束等方面的研究进展。     

外泌体作为siRNA递送载体的研究进展

小干扰RNA （small interference RNA,siRNA）可以选择性靶向和下调致病基因,在治疗人类疾病,特别是恶性肿瘤方面具有很大前景。为了增强siRNA递送系统的靶向性和治疗效果,许多载体已被广泛研究。外泌体存在于机体内源性系统,具有较高的生物相容性、低免疫原性、主动靶向性等优点,是一种很有潜力的siRNA递送载体。本文对外泌体siRNA递送系统的优势与不足、siRNA载入外泌体的方式、外泌体介导siRNA靶向递送及应用等进行了综述,旨在为外泌体作为一种新型靶向载体用于siRNA递送系统的研究提供参考。     

适配子介导siRNA靶向递送系统的研究进展

RNA干扰技术(RNAi)作为一种新型的基因治疗技术已应用到许多疾病的体外研究中,但靶向递送技术仍是目前制约小干扰RNA(siRNA)药物成功进入临床的关键技术问题。寡核苷酸适配子具有高亲和性、高靶向性,成为递送siRNA的重要手段。本文综述了siRNA体内递送的主要障碍,以及近年来适配子介导的siRNA靶向递送系统的最新研究进展。     

壳聚糖衍生物作为siRNA纳米递送系统材料的研究进展

小干扰RNA(small interfering RNA,siRNA)在治疗疾病方面具有高效性、特异性、瞬时性等优良特性,是目前药物研发关注的焦点。但裸露的siRNA稳定性差、细胞摄取率低,难以发挥其基因沉默作用,因此需要一种优质的递送系统将其递送至靶细胞中,使其发挥作用。大部分纳米递送系统因毒性、载药问题不利于siRNA的转运,而壳聚糖衍生物具有较高的水溶性、安全性、稳定性,已受到广泛关注。本文综述了壳聚糖衍生物应用于siRNA纳米递送系统的研究进展,为正在进行纳米递送系统研究的科研工作者提供参考。     

siRNA新型非病毒载体递送策略新进展

小干扰RNA(siRNA)是一个靶向治疗和精确医学的代表性治疗工具,可通过序列特异性的RNA干扰(RNAi)沉默任何疾病相关基因的表达。然而,它的治疗前景历来受到体内半衰期短、递送困难和安全问题的限制。非病毒载体介导的药物递送已经成为克服这些局限性的一个成功策略,可实现siRNA在体内的有效递送,高效沉默靶基因。目前,已有多种药物处于临床试验中,4种基于siRNA的新型疗法已获得美国FDA的批准,标志着靶向疗法新时代的开始。该文概述了近年来基于siRNA的非病毒载体递送策略的新进展及其应用,并展望了siRNA药物研究的未来发展趋势。     

高分子聚合物用于siRNA递送系统的研究进展

小干扰RNA（siRNA）具有沉默互补的目标信使RNA（mRNA）从而抑制疾病相关基因表达的作用。因其高效性及特异性,siRNA具有作为基因药物的巨大潜力,但其在体内易受到血管屏障、内涵体及RNA酶等因素的影响,从而难以发挥药效。因此,设计高效的能够负载siRNA的纳米载体以使其富集至靶标是目前siRNA药物研发的重要任务,高分子聚合物纳米载体是目前研究热点之一。本文就高分子聚合物纳米载体实现siRNA药物递送的研究进展进行综述。     

外泌体作为药物递送载体的研究进展

外泌体是一种由细胞主动分泌的纳米级脂质双层囊泡,其腔内或脂质双分子层中包裹着蛋白质、脂质和核酸等多种生物成分。外泌体具有低免疫原性、高物理化学稳定性、高组织穿透能力,以及先天的运输能力,因此有望成为一类新型的药物递送载体。目前,外泌体作为药物递送载体的研究已取得了可喜的进展,有关外泌体分离以及提高其药物负载和递送效率的新方法不断涌现。然而,仍有许多困难制约了外泌体的临床应用。综述了外泌体作为药物递送载体的研究进展,对外泌体大规模生产和纯化中的技术难点进行了分析,并总结了外泌体用于药物递送的法规问题。     

非病毒siRNA载体研究进展

研发siRNA类药物成为人类未来药物的主攻方向之一。然而,siRNA自身的不稳定性以及体内复杂的环境限制了siRNA在体内安全有效的递送。因此,siRNA需要借助特定的载体才能发挥生物学效应。该文综述了非病毒类载体在提高siRNA体内递送效率方面的研究进展。     

纳米微粒系统介导小干扰RNA体内递送的研究进展

目的:为开发新型纳米微粒系统用于体内递送小干扰RNA(siRNA)提供参考。方法:总结siRNA体内递送障碍并综述近年来纳米微粒系统介导siRNA体内递送的研究现状。结果与结论:siRNA需要解决肾滤过、吞噬细胞摄取、血清蛋白凝聚以及内源性核酸酶降解等障碍。聚乳酸-乙醇酸共聚物纳米微粒系统能有效包载siRNA,改善其体内稳定性,但存在内含体逃逸及不能及时释放siRNA的缺陷;壳聚糖纳米微粒系统包载siRNA稳定性高、包封率达83%～94%、基因沉默效率接近80%;环糊精纳米微粒系统包载siRNA未见严重毒副作用;胶束纳米微粒系统能有效保护siRNA免受核酸酶降解,并能适时释放siRNA;阳离子共聚物纳米微粒系统能有效防止siRNA被核酸酶降解,但转染效率低;脂质纳米微粒系统可显著提高siRNA对靶基因的沉默效果,但存在一定毒性及易引起siRNA脱靶效应。部分荷载siRNA的纳米微粒系统用于临床试验已得到了令人鼓舞的成果,但仍有较多问题亟待解决。联合应用多种递送系统传送siRNA可能是未来研究发展趋势。     

siRNA的体内递送及药物代谢动力学特性

siRNA作为一种高效的RNA干扰药物在疾病治疗方面前景广阔。但其临床应用还需解决由于高负电荷和分子量等引起的体内递送系统、脱靶效应、免疫激活、毒副作用、改善其药物代谢动力学特性等问题。本文简要综述了siRNA的作用原理、体内递送方式、药代动力学特性、安全问题及临床应用展望。     

用于肿瘤治疗的小分子干扰RNA非病毒载体研究进展

近年来,小分子干扰RNA(siRNA)作为RNA干扰 (RNAi) 技术的效应分子,已被广泛用于恶性肿瘤的基因治疗领域。欲获得理想的治疗效果,其关键因素是寻找一种安全、高效、稳定、可控的基因载体。非病毒载体具有低毒、低免疫原性、制备简单、目的基因容量大、外源基因随机整合率低且携带基因大小类型不受限制等突出优势,已经成为目前siRNA载体的研究热点。在以往学者的研究基础上,从药剂学的角度,笔者对这些载体在siRNA传递系统中的研究现况做回顾性总结。     

Chitosan-Thiamine Pyrophosphate as a Novel Carrier for siRNA Delivery

Purpose  A novel siRNA carrier was formulated between chitosan (CS) and thiamine pyrophosphate (TPP). Their ability to deliver siRNA were evaluated in stable and constitutive EGFP-expressing HepG2 cells. Methods  CS-TPP was prepared by dissolving CS in TPP solution at a CS:TPP molar ratio of 1.5:1. Complexes of CS-TPP/siRNA were formed at varying weight ratios and characterized using gel electrophoresis. Their morphologies and particle sizes were evaluated, and the transfection efficiency and cytotoxicity of CS-TPP/siRNA complexes were examined in stable and constitutive EGFP-expressing HepG2 cells. Results  Gel electrophoresis results indicated that binding of CS-TPP and siRNA depended on the molecular weight (MW) and weight ratio of CS, and the particle sizes of CS-TPP/siRNA complexes were in nano-size. The CS-TPP-mediated siRNA silencing of the endogenous EGFP gene occurred maximally with 70–73% efficiency. The CS-TPP/siRNA complex with the lowest MW of CS (20 kDa) at a weight ratio of 80 showed the strongest inhibition of gene expression, which was higher than Lipofectamine 2000™. Over 90% the average cell viabilities of the complexes were observed by MTT assay. Conclusions  This study suggests that CS-TPP is straightforward to prepare, safe and exhibits significantly improved siRNA delivery potential in vitro.     

Recent advances of siRNA delivery by nanoparticles

Introduction: The field of RNA interference technology has been researched extensively in recent years. However, the development of clinically suitable, safe and effective drug delivery vehicles is still required.

Areas covered: This paper reviews the recent advances of non-viral delivery of small interfering RNA (siRNA) by nanoparticles, including biodegradable nanoparticles, liposomes, polyplex, lipoplex and dendrimers. The characteristics, composition, preparation, applications and advantages of different nanoparticle delivery strategies are also discussed in detail, along with the recent progress of non-viral nanoparticle carrier systems for siRNA delivery in preclinical and clinical studies.

Expert opinion: Non-viral carrier systems, especially nanoparticles, have been investigated extensively for siRNA delivery, and may be utilized in clinical applications in the future. So far, a few preliminary clinical trials of nanoparticles have produced promising results. However, further research is still required to pave the way to successful clinical applications. The most important issues that need to be focused on include encapsulation efficiency, formulation stability of siRNA, degradation in circulation, endosomal escape and delivery efficiency, targeting, toxicity and off-target effects. Pharmacology and pharmacokinetic studies also present another great challenge for nanoparticle delivery systems, owing to the unique nature of siRNA oligonucleotides compared with small molecules.     

Cyclodextrin-based siRNA delivery nanocarriers: a state-of-the-art review

Introduction: The discovery of synthetic small interfering RNA (siRNA) has led to a surge of interest in harnessing RNA interference (RNAi) technology for biomedical applications and drug development. Even though siRNA can be a powerful therapeutic drug, its delivery remains a major challenge, due to the difficulty in its cellular uptake. Naked siRNA has a biological half-life of less than an hour in human plasma. To increase the lifetime and improve its therapeutic efficacy, non-viral vectors have been developed. As a natural evolution, cyclodextrins (CDs), which are natural cyclic oligosaccharides, have recently been applied as delivery vehicles for siRNA, and this in turn, has led to a surge of interest in this area.

Areas covered: This review discusses the recent advances made in the design of delivery strategies for siRNA, focusing on CD-based delivery vectors, because these have demonstrated clinical success. The methods of preparation of CD-based vectors, their characterization, transfection efficiencies, cellular toxicity, preclinical and clinical trials are also addressed, as well as future therapeutic applications.

Expert opinion: siRNA-mediated RNAi therapeutics is beginning to transform healthcare, particularly, for the treatment of solid tumors. For example, CALAA01, a targeted, self-assembling nanoparticle system based on CD complexed with siRNA has been effective in phase I clinical trials. Although siRNA therapeutics suffers from problems related to off-target effects and non-specific gene silencing, these problems can be overcome by reducing the nanoparticle size, improving the targeting efficiency and by modifying the primary sequence of the siRNA.     

siRNA Therapeutics: Future Promise for Neurodegenerative Diseases

Neurodegenerative diseases (ND), as a group of central nervous system (CNS) disorders, are among the most prominent medical problems of the 21^st century. They are often associated with considerable disability, motor dysfunction and dementia and are more common in the aged population. ND imposes a psychologic, economic and social burden on the patients and their families. Currently, there is no effective treatment for ND. Since many ND result from the gain of function of a mutant allele, small interference RNA (siRNA) can be a potential therapeutic agent for ND management. Based on the RNA interference (RNAi) approach, siRNA is a powerful tool for modulating gene expression through gene silencing. However, there are some obstacles in the clinical application of siRNA, including unfavorable immune response, off-target effects, instability of naked siRNA, nuclease susceptibility and a need to develop a suitable delivery system. Since there are some issues related to siRNA delivery routes, in this review, we focus on the application of siRNA in the management of ND treatment from 2000 to 2020.