RNA干扰在疾病治疗方面的应用研究

RNA干扰是由双链RNA引起的序列特异的基因沉默现象。由于RNA干扰能在细胞组织及动物模型中沉默疾病相关基因,因此,RNA干扰也是各种疾病治疗的有效手段。在哺乳动物细胞内诱导RNA干扰可以通过导入小干扰RNA（siRNA）,或是以质粒、病毒为载体表达短的发夹RNA（shRNA）而实现。本文介绍了RNA干扰在疾病治疗方面的应用,并就其面临的挑战进行讨论。     

RNA干扰技术治疗疾病

RNA干扰(RNA interference,RNAi)现象最早发现于秀丽隐杆线虫(Caenorhabditis elegans),随后发现该现象普遍存在于真菌、植物和哺乳动物等真核生物,并行使基因调控和抵御外源基因片段侵袭的作用。目前,RNAi分子机制和RNAi在基因功能方面的研究已经取得了突破性的进展。鉴于RNAi在基因沉默中的特异性、高效性和易操作,其在药物筛选和疾病治疗等方面有着广泛的应用前景。然而,RNAi技术用于治疗疾病的安全性尚待确定,分子传递途径也有待进一步的研究。     

RNA干扰在植物中的作用机理及其应用研究进展

RNA干扰(RNAi)是广泛存在于生物中的一种现象,它是小干扰RNA诱导的转录后基因沉默,是生物抵抗异常DNA的一种保护机制,同时在生物生长发育过程中调控基因的表达.本文综述了近年来有关RNA干扰的发现、作用过程及其机理,分析了它与反义寡核苷酸、核酶、脱氧核酶的小同,并介绍了RNA干扰在植物基因功能、植物抗病毒、作物品种改良等方面的应用,为siRNA干扰的进一步利用提供参考资料.     

RNA干扰技术在基因治疗中的应用进展

RNA干扰(RNA interference,RNAi)是一种双链RNA分子在mRNA水平上关闭相应序列基因的表达或使其沉默的过程,在基因治疗方面有着无可比拟的优势,已成功的应用于肿瘤、病毒感染、遗传性疾病及神经系统疾病等重大疾病的治疗.本文将主要介绍siRNA基因治疗的导入方法与途径,以及在不同疾病中,RNAi技术进行基因治疗的应用.     

基因枪在RNA干扰中的应用研究进展

RNA干扰（RNA interference,RNAi）是指双链RNA（double-strand RNA,dsRNA）特异性降解同源mRNA,从而引发基因转录后水平沉默的现象,是一种高效、高特异性抑制基因表达的途径。自1998年Fire等发现RNA干扰现象以来,其特异性降解目的基因的优势吸引了众多研究者的目光。本文在简要综述RNAi技术在基因功能研究、抗病毒治疗,肿瘤基因治疗等领域的应用后,重点归纳了基因枪技术在RNAi研究即siRNA导入细胞中的应用,并简单分析其优势与意义。     

RNA干扰应用新进展

RNAi是dsRNA诱导的序列特异的基因沉默,siRNA是主要诱因。该文重点综述siRNA的特征、合成方式、转染及转染后检测方法的研究进展;RNAi技术在细胞信号传导途径分析、冗余基因确定、基因功能检测、基因治疗、药物开发等研究领域应用新进展及在相关应用领域仍待解决的问题。     

RNA干扰药物用于疾病治疗的安全性问题

RNA干扰(RNA interference,RNAi)是指由双链RNA介导的序列特异的转录后基因沉默.RNAi技术因其特异性.高效性而备受青睐,在疾病治疗方面表现出广阔的应用前景.然而,近年来的研究发现,基于RNAi技术开发的药物存在安全性问题,主要包括引起免疫反应,产生脱靶效应、以及存在竞争微RNA通路等.这些问题的突破将使RNAi技术获得更加广泛的应用.     

RNA干扰药物用于疾病治疗的安全性问题

RNA干扰（RNA interference,RNAi）是指由双链RNA介导的序列特异的转录后基因沉默。RNAi技术因其特异性、高效性而备受青睐,在疾病治疗方面表现出广阔的应用前景。然而,近年来的研究发现,基于RNAi技术开发的药物存在安全性问题,主要包括引起免疫反应、产生脱靶效应、以及存在竞争微RNA通路等。这些问题的突破将使RNAi技术获得更加广泛的应用。     

siRNA纳米递送系统研究进展

小干扰RNA (small interfering RNA,siRNA)是RNA干扰的引发物,激发与之互补的目标mRNA沉默,对基因调控及疾病治疗有重要意义。siRNA作为药物需要克服血管屏障、实现细胞内吞及溶酶体逃逸,同时还需要避免核酸酶作用下发生降解。因此,设计合适的纳米载体以帮助siRNA成功递送进细胞并发挥作用是目前siRNA药物发展的重要目标。纳米载体的材料种类、尺寸、结构、表面修饰等精确设计是实现siRNA药物成功递送的重要因素。随着研究的深入和应用的发展,siRNA药物纳米载体的精确控制制备、精准靶向递送及多功能化取得了较好的成果。本文围绕siRNA药物纳米载体,对siRNA药物应用及其递送困难、siRNA药物纳米载体主要设计策略、目前siRNA药物上市情况进行介绍,同时对其未来发展方向进行展望。     

siRNA脱靶效应研究进展

RNA干扰过程中,siRNA和mRNA特异结合能够使得靶基因沉默。但研究证实,siRNA可能与非靶基因结合而导致非靶基因沉默,这种现象称为siRNA脱靶效应。多种真核生物中的RNA干扰实验证实了脱靶效应的存在。对脱靶机制的研究发现脱靶可能与模体匹配、结构和长dsRNA等有关,很多新方法被提出来预测脱靶概率和检测脱靶基因。通过利用siRNApool、化学修饰和生物信息学方法能够尽可能地降低脱靶效应,提高RNAi实验的质量。对脱靶效应方面的研究进行了总结论述。     

Local RNA target structure influences siRNA efficacy: systematic analysis of intentionally designed binding regions

Contradictory reports in the literature have emphasised either the sequence of small interfering RNAs (siRNA) or the structure of their target molecules to be the major determinant of the efficiency of RNA interference (RNAi) approaches. In the present study, we analyse systematically the contributions of these parameters to siRNA activity by using deliberately designed mRNA constructs. The siRNA target sites were included in well-defined structural elements rendering them either highly accessible or completely involved in stable base-pairing. Furthermore, complementary sequence elements and various hairpins with different stem lengths and designs were used as target sites. Only one of the strands of the siRNA duplex was found to be capable of silencing via its respective target site, indicating that thermodynamic characteristics intrinsic to the siRNA strands are a basic determinant of siRNA activity. A significant obstruction of gene silencing by the same siRNA, however, was observed to be caused by structural features of the substrate RNA. Bioinformatic analysis of the mRNA structures suggests a direct correlation between the extent of gene-knockdown and the local free energy in the target region. Our findings indicate that, although a favourable siRNA sequence is a necessary prerequisite for efficient RNAi, complex target structures may limit the applicability even of carefully chosen siRNAs.     

siRNA制备技术的研究进展

近年来,siRNA(small interfering RNA)被广泛用于诱导哺乳动物体系中的RNA干扰。目前有五种siRNA制备方法：化学合成法、体外转录法、RNase Ⅲ家族体外消化法、表达载体法和表达框架法。在这些方法中siRNA序列的选择至关重要。随着药物研究和基因组研究的进展,siRNA的制备技术需要在高通量筛选、稳定性、基因导入和调控等方面进一步发展与完善。作者综述了siRNA序列的选择原则和哺乳动物系统中的siRNA产生方法,并简要讨论了其发展前景。     

Genome-wide application of RNAi to the discovery of potential drug targets

Progress is being made in the development of RNA interference-based (RNAi-based) strategies for the control of gene expression. It has been demonstrated that small interfering RNAs (siRNAs) can silence the expression of target genes in a sequence-specific manner in mammalian cells. Various groups, including our own, have developed systems for vector-mediated specific RNAi. Vector-based siRNA- (or shRNA) expression libraries directed against the entire human genome and siRNA libraries based on chemically synthesized oligonucleotides now allow the rapid identification of functional genes and potential drug targets. Use of such libraries will enhance our understanding of numerous biological phenomena and contribute to the rational design of drugs against heritable, infectious and malignant diseases.     

RNA干扰引起的非特异性免疫反应及其机制研究探讨

基因的表达失控是疾病发生的主要原因之一,干扰靶基因的表达可能成为有效的治疗手段。RNA干扰技术是近年兴起的基因调控干预方法,其基础,特别是应用研究极受关注,人们期待RNA干扰能成为肿瘤、病毒感染等难治疾病的临床治疗手段。然而,这一新兴技术在应用研究过程中显现出诸多问题,如细胞毒性、引起机体非特异性反应等等。就RNA干扰引起的非特异性免疫反应展开综述,探讨其机制,期望为RNA干扰的应用研究提供一些思考。     

A comparison of siRNA efficacy predictors

Short interfering RNA (siRNA) efficacy prediction algorithms aim to increase the probability of selecting target sites that are applicable for gene silencing by RNA interference. Many algorithms have been published recently, and they base their predictions on such different features as duplex stability, sequence characteristics, mRNA secondary structure, and target site uniqueness. We compare the performance of the algorithms on a collection of publicly available siRNAs. First, we show that our regularized genetic programming algorithm GPboost appears to have a higher and more stable performance than other algorithms on the collected datasets. Second, several algorithms gave close to random classification on unseen data, and only GPboost and three other algorithms have a reasonably high and stable performance on all parts of the dataset. Third, the results indicate that the siRNAs' sequence is sufficient input to siRNA efficacy algorithms, and that other features that have been suggested to be important may be indirectly captured by the sequence.     

The potential therapeutic of siRNA eye drops in ocular diseases

In recent years, researchers have expressed an ongoing interest in developing RNA interference (RNAi) technology for therapeutic gene suppression in various diseases. Preclinical studies in animal models and cultured cell studies indicated that RNAi technology was an effective experimental tool against a variety of ocular diseases, and some small interference RNA (siRNA) drugs have been entered into clinical trials in Stage I and Stage II. However, in these studies siRNAs were delivered into ocular tissues via either systemic or subconjunctival/intravitreous injection, which is invasive and harmful if repeated. Based on this evidence, we hypothesize that topical application of siRNA eye drops may be a safe and effective therapeutic option in ocular surface diseases with temporary changes of gene expression. Furthermore, siRNA eye drops targeting different genes may simultaneously treat several ocular surface diseases.