Applications and developments of gene therapy drug delivery systems for genetic diseases

Genetic diseases seriously threaten human health and have always been one of the refractory conditions facing humanity.Currently,gene therapy drugs such as siRNA,shRNA,antisense oligonucleotide,CRISPR/Cas9 system,plasmid DNA and miRNA have shown great potential in biomedical applications.To avoid the degradation of gene therapy drugs in the body and effectively deliver them to target tissues,cells and organelles,the development of excellent drug delivery vehicles is of utmost importance.Viral vectors are the most widely used delivery vehicles for gene therapy in vivo and in vitro due to their high transfection efficiency and stable transgene expression.With the development of nanotechnology,novel nanocarriers are gradually replacing viral vectors,emerging superior performance.This review mainly illuminates the current widely used gene therapy drugs,summarizes the viral vectors and non-viral vectors that deliver gene therapy drugs,and sums up the application of gene therapy to treat genetic diseases.Additionally,the challenges and opportunities of the field are discussed from the perspective of developing an effective nano-delivery system.

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。

Non-viral and viral delivery systems for CRISPR-Cas9 technology in the biomedical field

The clustered regularly interspaced short palindromic repeats(CRISPR)-associated protein 9(CRISPR-Cas9) system provides a novel genome editing technology that can precisely target a genomic site to disrupt or repair a specific gene. Some CRISPR-Cas9 systems from different bacteria or artificial variants have been discovered or constructed by biologists, and Cas9 nucleases and single guide RNAs(sgRNA) are the major components of the CRISPR-Cas9 system. These Cas9 systems have been extensively applied for identifying therapeutic targets, identifying gene functions, generating animal models, and developing gene therapies.Moreover, CRISPR-Cas9 systems have been used to partially or completely alleviate disease symptoms by mutating or correcting related genes. However, the efficient transfer of CRISPR-Cas9 system into cells and target organs remains a challenge that affects the robust and precise genome editing activity. The current review focuses on delivery systems for Cas9 mRNA, Cas9 protein, or vectors encoding the Cas9 gene and corresponding sgRNA. Non-viral delivery of Cas9 appears to help Cas9 maintain its on-target effect and reduce off-target effects, and viral vectors for sgRNA and donor template can improve the efficacy of genome editing and homology-directed repair. Safe, efficient, and producible delivery systems will promote the application of CRISPR-Cas9 technology in human gene therapy.

Design, mechanism, delivery and therapeutics of canonical and Dicer-substrate siRNA

Upon the discovery of RNA interference(RNAi),canonical small interfering RNA(si RNA) has been recognized to trigger sequence-specific gene silencing. Despite the benefits of si RNAs as potential new drugs,there are obstacles still to be overcome,including off-target effects and immune stimulation. More recently,Dicer substrate si RNA(Dsi RNA) has been introduced as an alternative to si RNA. Similarly,it also is proving to be potent and target-specific,while rendering less immune stimulation. Dsi RNA is 25–30 nucleotides in length,and is further cleaved and processed by the Dicer enzyme. As with si RNA,it is crucial to design and develop a stable,safe,and efficient system for the delivery of Dsi RNA into the cytoplasm of targeted cells. Several polymeric nanoparticle systems have been well established to load Dsi RNA for in vitro and in vivo delivery,thereby overcoming a major hurdle in the therapeutic uses of Dsi RNA. The present review focuses on a comparison of si RNA and Dsi RNA on the basis of their design,mechanism,in vitro and in vivo delivery,and therapeutics.

Clinical applications of the CRISPR/Cas9 genome-editing system: Delivery options and challenges in precision medicine

CRISPR/Cas9 is an effective gene editing tool with broad applications for the pre-vention or treatment of numerous diseases.It depends on CRiSPR(clustered regularly inter-spaced short palindromic repeats)as a bacterial immune system and plays as a gene editing tool.Due to the higher specificity and efficiency of CRISPR/Cas9 compared to other editing ap-proaches,it has been broadly investigated to treat numerous hereditary and acquired ill-nesses,including cancers,hemolytic diseases,immunodeficiency disorders,cardiovascular diseases,visual maladies,neurodegenerative conditions,and a few X-linked disorders.CRISPR/Cas9 system has been used to treat cancers through a variety of approaches,with sta-ble gene editing techniques.Here,the applications and clinical trials of CRisPR/Cas9 in various illnesses are described.Due to its high precision and efficiency,CRISPR/Cas9 strategies may treat gene-related illnesses by deleting,inserting,modifying,or blocking the expression of specific genes.The most challenging barrier to the in vivo use of CRISPR/Cas9 like off-target effects will be discussed.The use of transfection vehicles for CRISPR/Cas9,including viral vectors(such as an Adeno-associated virus(AAV),and the development of non-viral vectors is also considered.

将目标物质靶向至心脏的研究进展

当前心血管疾病的发病率和死亡率仍位居全球前列。随着分子生物学和细胞心脏病学知识的不断更新,基因治疗已在临床研究中有了长足的进步。然而对于如何将目的细胞或基因成功运送到心脏并发挥作用,仍需克服各种障碍,如解剖、血流机械力、内皮屏障、细胞屏障以及免疫应答等。病毒和非病毒载体,一些细胞及细胞外囊泡、生物材料、外科手术等方法已被广泛运用于各种临床前实验当中。

When mRNA meets gene editing

The critical challenge of gene therapy lies in delivering gene editing agents.Compared with DNA,while RNA is less stable and more accessible to degrade,it comes with the benefit of lower off-target effects since permanent insertion is not involved.This review focuses on mRNA-based delivery of gene editing agents,highlighting novel mRNA delivery systems.To provide context,a comparison is made between three main gene editing agents:programmable nucleases,base editors,and prime editors.The potential of Cas\pi and transposons is also discussed in this review.Additionally,a summary of four main barriers to mRNAbased in vivo delivery is provided.Furthermore,this review detailedly introduced different delivery systems,both viral(lentivirus)and non-viral vectors(genome editing via oviductal nucleic acids delivery,lipid nanoparticles,polymer-based nanoparticles,viruslike-particles,extracellular vesicles,and migrasome).Each delivery strategy is assessed by comparing its advantages and disadvantages to offer a comprehensive and objective overview of the delivery system.Moreover,we emphasized the vital role of the protein corona as a critical regulator for nanodelivery.Ultimately,we concluded the challenges of mRNA-based gene editing strategies(RNA stability,targeting,potential immunogenicity,cytotoxicity,heterogeneity,and rational design).The purpose of this review is to guide further research and provide a comprehensive analysis of mRNA-based in vivo delivery of gene editing agents in this promising field.

基因治疗导入载体的研究进展

基因治疗在恶性肿瘤、癌症、遗传性疾病和心脑血管等疾病的治疗中开始应用,临床治疗效果明显。基因治疗中的关键技术是选用合适的载体将外源基因高效导入受体靶细胞,综述了基因治疗中病毒和非病毒载体的研究进展。

非病毒载体在基因治疗中的发展与应用

构建基因载体并建立安全高效的基因载体体内投递系统是基因治疗的关键。基因载体分病毒与非病毒载体。病毒载体转染高效,已应用于临床,但仍面临安全性低的问题。非病毒载体制备简单、安全性高、潜力大;然而,转染效率低的问题限制了其临床应用。基因治疗领域的研究者一直致力于优化非病毒载体投递系统,提高转染效率,已经出现可应用于临床的基因投递产品。文章旨在回顾非病毒基因载体的研究进展及其临床应用前景。

非病毒基因递送载体的研究进展

目前,基因药物的递送成为药学研究的热点,基因递送载体主要包括病毒载体和非病毒载体。非病毒基因载体的毒性低,生物相容性好,转染效率高,具有潜在的临床应用价值。本文就靶向递送基因载体、多功能基因载体、同时载基因与化疗药物的载体、智能基因载体和脂质体等非病毒基因递送载体的研究进展做一综述。

Gene therapy: light is finally in the tunnel

After two decades of ups and downs,gene therapy has recently achieved a milestone in treating patients with Leber’s congenital amaurosis(LCA).LCA is a group of inherited blinding diseases with retinal degeneration and severe vision loss in early infancy.Mutations in several genes,including RPE65,cause the disease.Using adenoassociated virus as a vector,three independent teams of investigators have recently shown that RPE65 can be delivered to retinal pigment epithelial cells of LCA patients by subretinal injections resulting in clinical benefits without side effects.However,considering the whole field of gene therapy,there are still major obstacles to clinical applications for other diseases.These obstacles include innate and immune barriers to vector delivery,toxicity of vectors and the lack of sustained therapeutic gene expression.Therefore,new strategies are needed to overcome these hurdles for achieving safe and effective gene therapy.In this article,we shall review the major advancements over the past two decades and,using lung gene therapy as an example,discuss the current obstacles and possible solutions to provide a roadmap for future gene therapy research.

Efficient drug and gene delivery to liver fibrosis:rationale, recent advances, and perspectives

Liver fibrosis results from chronic damages together with an accumulation of extracellular matrix,and no specific medical therapy is approved for that until now.Due to liver metabolic capacity for drugs,the fragility of drugs,and the presence of insurmountable physiological obstacles in the way of targeting,the development of efficient drug delivery systems for anti-fibrotics seems vital.We have explored articles with a different perspective on liver fibrosis over the two decades,then collected and summarized the information by providing corresponding in vitro and in vivo cases.We have discussed the mechanism of hepatic fibrogenesis with different ways of fibrosis induction in animals.Furthermore,the critical chemical and herbal anti-fibrotics,biological molecules such as micro-RNAs,siRNAs,and growth factors,which can affect cell division and differentiation,are mentioned.Likewise,drug and gene delivery and therapeutic systems on in vitro and in vivo models are summarized in the data tables.This review article enlightens recent advances in emerging drugs and nanocarriers and represents perspectives on targeting strategies employed in liver fibrosis treatment.

Gene delivery in peritoneal dialysis related peritoneal fibrosis research

Objective To summarize the development of gene delivery vectors in peritoneal fibrosis research and discuss the feasibility and superiority of lentiviral vectors. Data sources The data in this article were collected from PubMed database with relevant English articles published from 1995 to 2011. Study selection Articles regarding the gene therapy in peritoneal fibrosis research using non-viral vectors, adenoviral vectors, retroviral vectors, and lentiviral vectors were selected. Data were mainly extracted from 60 articles, which are listed in the reference section of this review. Results Non-viral vector-mediated gene delivery （including naked DNA for ex vivo, oligonucleotides, ultrasound- contrast agent mediated naked gene delivery, etc.） and viral vector-mediated gene delivery （including adenovirus, helper-dependant adenovirus, and retrovirus vectors） have been successfully applied both in the mechanistic investigation and the potential prevention and treatment of peritoneal fibrosis. Conclusions Peritoneal fibrosis is a major complication of peritoneal dialysis （PD）. Recently, the wide use of the gene delivery technique made it possible to access and further research peritoneal fibrosis. The use of lentiviral vector is expected to be widely used in PD research in the future due to its advantages in gene delivery.

Folate-conjugated polyspermine for lung cancer–targeted gene therapy

Biodegradable polyamines have long been studied as potential recombinant viral gene vectors.Spermine(SPE) is an endogenous tetra-amine with excellent biocompatibility yet poor gene condensation capacity. We have previously synthesized a polyspermine based on SPE and poly(ethylene glycol)(PEG)diacrylate(SPE-alt-PEG) for enhanced transfection performance, but the synthesized SPE-alt-PEG still lacked specificity towards cancer cells. In this study, folic acid(FA) was incorporated into SPE-alt-PEG to fabricate a targeted gene delivery vector(FA-SPE-PEG) via an acylation reaction. FA-SPE-PEG exhibited mild cytotoxicity in both cancer cells and normal cells. FA-SPE-PEG possessed higher transfection efficiency than PEI 25 K and Lipofectamines2000 in two tested cancer cell lines at functional weight ratios, and its superiority over untargeted SPE-alt-PEG was prominent in cells with overexpressed folate receptors(FRs). Moreover, in vivo delivery of green fluorescent protein(GFP) with FA-SPE-PEG resulted in highest fluorescent signal intensity of all investigated groups. FA-SPE-PEG showed remarkably enhanced specificity towards cancer cells both in vivo and in vitro due to the interaction between FA and FRs. Taken together, FA-SPE-PEG was demonstrated to be a prospective targeted gene delivery vector with high transfection capacity and excellent biocompatibility.

非病毒(合成)基因递送载体研究进展

以基因治疗领域中非病毒载体的种类为主线,系统介绍了各种非病毒载体的特性及临床应用前景,为其未来改性、开发应用提供参考。

Peptide-based DNA delivery system

Gene therapy is defined as the ability to change individual's genetics by correcting genetic mutations or making site-specific alterations that target therapeutic treatment.The focus of gene therapy is optimization of delivery vectors.Peptide-based DNA delivery vaccine is a field in non-viral gene delivery systems and not many researchers have looked after it.DNA vaccines have many appealing production potentials,including the ability to provide cross-protection against various virus subtypes,mass manufacturing in a reasonably short period,and greater stability than other delivery systems.Non-viral approaches are considered benign than viral delivery because of factors such as lack of immunogenicity,low toxicity,and the potential for tissue specificity.DNA vaccines have several limitations but,in this review,we focus on how a novel peptide R9-K-GALA can be used in DNA vaccine and overcome almost all the pitfalls.It is also expected that this delivery system can be used to protect against Malaria.R9-K-GALA is a novel peptide,and arginine(R)is used in this peptide because GALA cannot directly bind to DNA.So,Arginine will help to bind DNA as arginine being positively charged and DNA is negatively charged.This review mainly focuses on how peptides can be used to make DNA vaccines and how DNA vaccines in the coming future can be a breakthrough for many diseases.

多糖类材料在基因递释系统中的应用

基因治疗需要将外源正常基因导入靶细胞,以纠正或补偿因基因缺陷和异常引起的疾病,以达到治疗目的。为了增加外源性基因的转染效率,必须借助适宜的载体,现常用的载体分为病毒载体(如腺病毒载体)与非病毒载体。与病毒载体相比,非病毒载体如多糖类载体具有来源广泛,安全性高,无毒,生物相容性好,高度可修饰性等特点,具有广泛的应用前景。文章就多糖类材料在基因递释系统中的应用进行了综述。

非病毒载体基因递送系统的研究进展

非病毒载体基因递送系统是相对于以病毒为载体的基因递送系统的另一种基因递送系统。具有高安全性、低免疫原性及易于生产的特性。本文就非病毒基因载体的种类、在疾病治疗中的应用前景及存在的主要问题作一综述。

眼部疾病的基因治疗与递送策略

眼睛独特的生理构造使其在基因治疗方面彰显出明显的优势。近年来,越来越多治疗眼部疾病的基因药物进入临床试验,其中大部分是以腺相关病毒作为递送载体,通过局部注射途径给药,存在一定的风险。针对各种眼部疾病,传统的无创治疗手段如眼表滴入或全身给药虽能够达到一定的治疗效果,但是对于眼内和眼后段疾病,即使小分子药物也难以到达,这使得对基因药物眼部递送策略的研究迫在眉睫。为了更好地了解基因治疗眼部疾病的最新热点,本文介绍了相关的疾病与基因药物,总结了眼内基因递送的途径与吸收屏障,并侧重介绍了近年来报道的基因递送策略。克服眼部的吸收屏障并降低给药的潜在风险,有望为眼部基因治疗的临床应用带来曙光。

类风湿性关节炎基因治疗的研究进展

基因治疗是生物治疗的重要领域之一。近年来,类风湿性关节炎的基因治疗得到越来越多的关注。该文对类风湿性关节炎基因治疗的研究进行了综述,重点介绍了治疗类风湿性关节炎的目标基因和递送方法,为发展类风湿性关节炎的基因治疗提供参考。