纳米递送系统在mRNA肿瘤疫苗中的研究进展

肿瘤疫苗是肿瘤免疫治疗中极具发展前景的治疗策略之一,其通过递送肿瘤抗原促进抗原递呈过程,进而激活抗肿瘤免疫反应。信使RNA (messenger RNA, mRNA)疫苗是一种新型疫苗,通过向体内递送特定抗原的mRNA序列并表达相应抗原蛋白,从而激活机体免疫系统达到免疫治疗的目的。mRNA疫苗与传统疫苗相比具有生产周期短、有效性高和免疫原性强等优势,近年来mRNA疫苗在肿瘤免疫治疗中的应用引起广泛关注,但mRNA的不稳定性和低递送效率限制了其应用。纳米递送系统能有效解决mRNA疫苗递送的难题,极大地促进mRNA肿瘤疫苗的研究进程和临床应用,已成为mRNA疫苗研究的热点。本文对mRNA肿瘤疫苗进行介绍,重点对纳米递送系统在mRNA肿瘤疫苗中的应用进行综述,以期为mRNA肿瘤疫苗高效递送及肿瘤免疫治疗提供新思路和新方法。     

基因疫苗黏膜免疫及其机制的研究进展

基因疫苗是将编码外源性抗原的基因插入到含真核表达系统的载体质粒上,然后将重组质粒直接导人人或动物体内,让其在宿主细胞中表达抗原蛋白,诱导机体产生免疫应答.以达到预防疾病的目的.现已证实基因疫苗的有效性及安全性,但存在人体不能对基因疫苗进行有效的吸收以及机体对抗原的免疫耐受等不足,使其在人体中的免疫效果不佳.近年来,对基因疫苗的免疫策略、免疫效果及作用机制已进行了大量的研究.肌肉注射法因外源基因在体内的表达水平较低,免疫效果不够理想.基因枪法、电穿孔等递送技术的发展均显著提高了基因疫苗的活体递送效率,使基因疫苗免疫具有较强的诱导免疫应答的能力[1-2].     

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。     

体外转录合成mRNA递送材料的研究进展

信使RNA(mRNA)递送技术是指通过体外转录合成mRNA并递送至细胞内，表达出相应的蛋白进而发挥重要的生物学功能。近年来，mRNA递送技术在疫苗和基因治疗等方面成为研究的前沿和热点。mRNA一般采用纳米粒或非纳米粒材料包裹后进行递送。尽管取得了许多进展，但缺乏有效和无毒的递送材料仍然是限制mRNA应用的主要因素。病毒系统(如慢病毒和腺相关病毒)的使用已被广泛认为是核酸的有效递送方式，但不需要的免疫反应是其发展的根本障碍。因此，越来越多的非病毒载体(包括脂质、聚合物、基于纳米的载体或功能载体)作为安全、有效的递送工具受到关注。该文综述了近年来各种mRNA递送材料的进展、挑战及未来方向。     

纳米药物药代动力学研究——专栏致辞

<正>纳米载体作为一种创新型递释系统具有很多独特优势,例如靶向性,因此受到广泛研究,其中一些成功范例已经进入临床应用,特别是新冠疫情的爆发,促发了mRNA疫苗的广泛应用,而新冠mRNA疫苗成功的关键因素就是脂质纳米递送系统。虽然纳米药物的应用前景非常被看好,但是其临床转化研究还存在很多巨大的挑战,特别是纳米药物的时空命运研究,因此纳米药物的体内药代动力学评价也一直是纳米药物研究的重要环节。纳米药物进入体内后的处置机制复杂,产生多种形态成分,     

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。     

聚乙烯亚胺纳米基因递送系统的研究进展

基因治疗在恶性肿瘤、感染性疾病、自身免疫性疾病、罕见病等重大难治性疾病的治疗中表现出巨大潜力。基因递送载体是基因治疗能否成功实施的关键所在,聚乙烯亚胺（PEI）是一种被广泛研究的阳离子基因递送载体,在不同细胞系和转染条件下均展现出稳定高效的基因转染效果,其中PEI25k更被视作基因转染的“黄金标准”。为解决PEI在基因递送中存在的体内转染效率低、细胞毒性大、靶向性低和负载基因溶酶体降解等问题,该文对基于PEI设计构建新型纳米递送系统用于基因治疗的研究进展进行综述,主要包括高相对分子质量线性PEI、多糖、亲水性的聚合物和右旋糖酐修饰的PEI,交联的低相对分子质量PEI,基于PEI的无机纳米递送载体以及基于PEI的药物与基因共递送载体系统,以期为进一步构建高效低毒的基因递送系统提供理论指导。     

脂质纳米微粒载体在核酸药物递送中的应用

脂质微粒作为基因药物载体,用于全身药物递送,目前已进行了大量深入的研究。其中,脂质纳米微粒(lipid-based nanoparticles,NP)药物载体,在进行基因药物递送时,为克服体内的各种生理屏障,粒径需在100 nm以下,本文将重点介绍这类NP的配方和组装。NP作为一种核酸药物的脂质微粒递送载体,与阳离子脂质体/DNA复合物区别主要在于粒径大小,NP的粒径通常在100nm以下。影响NP粒径的主要因素包括脂质的构成、脂质与核酸的比例,以及制备方法等。NP所递送的核酸主要包括质粒DNA,siRNA,反义寡核苷酸。     

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。     

聚合物-脂质纳米粒用于增强酪氨酸血症I型治疗性碱基编辑器质粒的肝靶向递送研究（英文）

酪氨酸血症I型是一种罕见的常染色体隐性遗传病,目前尚无有效的治疗方法。近年来,以碱基编辑器为代表的基因编辑技术已被报道用于酪氨酸血症I型的治疗。然而,由于生理屏障的存在,碱基编辑器递送困难。在本研究中,我们构建了一种靶向去唾液酸糖蛋白受体的聚合物-脂质纳米递送系统,用于改善酪氨酸血症I型治疗性核酸药物的递送效率。我们首先合成了一种生物可降解性丙烯酸酯-氨基醇共聚物用于递送碱基编辑器质粒,其转染效率显著优于市售转染试剂Hieff Trans^TM。随后,共聚物纳米粒与DOPE-PEG-Gal NAc自组装形成聚合物-脂质纳米粒,用于增强纳米粒的肝脏递送效率。在体外转染实验中,包载Fah-p CMV-ABE6.3-EGFP碱基编辑器质粒的聚合物-脂质纳米粒表现出了良好的肝细胞选择性,其转染效率是游离质粒的70倍以上。研究表明,携带肝靶向配体的聚合物-脂质纳米递送系统能够有效增强治疗性碱基编辑器质粒的肝靶向递送效率并为酪氨酸血症I型的基因治疗提供了一种潜在的递送载体。     

基于杆状病毒表达系统的流感病毒样颗粒疫苗研究进展

流感疫苗是目前应对流感最有效的措施,传统疫苗包括全病毒灭活疫苗、裂解疫苗和减毒活疫苗,近年来逐渐成为研发趋势的有重组亚单位疫苗、核酸疫苗、活病毒载体疫苗等。病毒样颗粒(virus-like particle,VLP)疫苗作为特殊形式的亚单位疫苗,具有生产迅速、安全性高、免疫原性较高等优势。VLP可以高效地诱发体液免疫与细胞免疫,且可经多种途径接种。目前已有多种表达系统用于制备VLP,其中应用最为广泛的是杆状病毒表达系统。此文综述了流感病毒VLP的类型、组装、抗原选择、免疫途径以及流感病毒VLP疫苗在杆状病毒表达系统中的研究进展。     

mRNA vaccines: Past,present, future

mRNA vaccines have emerged as promising alternative platforms to conventional vaccines. Their ease of production, low cost, safety profile and high potency render them ideal candidates for prevention and treatment of infectious diseases, especially in the midst of pandemics. The challenges that face in vitro transcribed RNA were partially amended by addition of tethered adjuvants or co-delivery of naked mRNA with an adjuvant-tethered RNA. However, it wasn't until recently that the progress made in nanotechnology helped enhance mRNA stability and delivery by entrapment in novel delivery systems of which, lipid nanoparticles. The continuous advancement in the fields of nanotechnology and tissue engineering provided novel carriers for mRNA vaccines such as polymeric nanoparticles and scaffolds. Various studies have shown the advantages of adopting mRNA vaccines for viral diseases and cancer in animal and human studies. Self-amplifying mRNA is considered today the next generation of mRNA vaccines and current studies reveal promising outcomes. This review provides a comprehensive overview of mRNA vaccines used in past and present studies, and discusses future directions and challenges in advancing this vaccine platform to widespread clinical use.     

Topical delivery of plasmid DNA using biphasic lipid vesicles (Biphasix)

The development of non-invasive methods for the delivery of vaccines through the skin will greatly improve the safety and the administration of human and veterinary vaccines. In this study we examined the efficiency of topical delivery of plasmids by assessing the localization of gene expression using luciferase as a reporter gene and induction of immune responses using a plasmid encoding for the bovine herpesvirus type-1 glycoprotein D (pgD). Topical administration of plasmids in a lipid-based delivery system (biphasic lipid vesicles--Biphasix) resulted in gene expression in the lymph node, whereas with intradermal injection, antigen expression was found in the skin. Following administration of plasmid with the gene gun, antigen expression was observed in both the skin as well as in the draining lymph nodes. Transcutaneous immunization with pgD formulated in biphasic lipid vesicles elicited gD-specific antibody responses and a Th2-type cellular response. In contrast, immunization by the intradermal route resulted in the stimulation of a Th1-type response. These findings have implications for both vaccine design and tailoring of specific immune responses.     

Mucosal immunity elicited by DNA vaccines

The induction of mucosal immunity could improve vaccine prophylaxis by preventing pathogens from colonizing their host. As a consequence, the delivery of vaccines to mucosal surfaces has become a crucial issue. DNA vaccines, administered by intra-muscular injection or by particle bombardment of the epidermis, have revolutionized vaccine research in the last few years, but these routes of delivery are unlikely to elicit mucosal immunity efficiently. This article reviews the progress being made towards meeting the vital challenge of efficiently eliciting mucosal immunity through the appropriate delivery of DNA vaccines.     

Attenuated Salmonella and Shigella as Carriers for DNA Vaccines

The discovery that genes can be functionally transferred from bacteria to mammalian cells has suggested the possible use of bacterial vectors as gene delivery vehicles for vaccines. Attenuated invasive human intestinal bacteria, such as Salmonella and Shigella, have been used as plasmid DNA vaccine carriers and their potency has been evaluated in several animal models. This delivery system allows the administration of DNA vaccines together with associated bacterial immunostimulators directly to professional antigen presenting cells via human mucosal surfaces. Various strategies have been taken to improve the use of this delivery system to achieve robust immune responses at both mucosal and systemic sites of the immunized animals.     

mRNA疫苗技术概述及新型冠状病毒肺炎mRNA疫苗的研究进展

mRNA疫苗技术的发展受到分子本身不稳定、自身免疫原性高以及体内递送效率低等因素的限制，经过30多年的研究，近年来随着其稳定性、高效传递系统方面的技术日趋成熟，肿瘤和传染病mRNA疫苗研究进展明显。与传统疫苗技术相比，该技术可诱导机体产生体液免疫和细胞免疫，疫苗生产工艺简单、研发周期短、成本低，便于标准化生产，适用于大流行疾病和传染病暴发流行期间的疫苗开发和生产，是一种应用前景广阔的疫苗。在当前新型冠状病毒肺炎全球大流行的背景下，本文从mRNA疫苗的特征、疫苗递送系统入手，结合新型冠状病毒肺炎mRNA疫苗的研究现状进行了分析和阐述，以期为后续的mRNA疫苗研究开发提供参考依据。     

Development of a Chlamydia trachomatis bacterial ghost vaccine to fight human blindness

Trachoma is the world's leading cause of preventable disease and the third most common cause of blindness after cataract and glaucoma, affecting an estimated 84 million people and leaving 590 million at risk. As a crippling disease, trachoma causes an enormous loss of productivity and constitutes a major socioeconomic burden. Although antibiotics are effective in treating active cases of the illness, they do not prevent re-infection, which occurs with high frequency in susceptible populations. Also, once infection and pathology are established, treatment may be less effective. Another major public health challenge posed by trachoma is that a large number of infected individuals are asymptomatic and readily infect those with whom they interact. Thus, an inexpensive and easy to deliver vaccine for trachoma would be highly effective in reducing the devastation caused by this disease. Development of an effective vaccine for controlling and preventing trachoma will require an understanding of the complex immunological mechanisms that occur during infection, identifying those antigens that elicit a protective immune response and designing effective vaccine delivery systems. Significant progress has been made in the delineation of the immune correlates of protection that will form the basis of vaccine evaluation. Recent advances in chlamydial genomics and proteomics has identified a number of protective antigens or epitopes that when appropriately delivered will produce an efficacious vaccine. The challenge at this time is the development of effective methods for vaccine delivery. We have developed an effective bacterial ghost (BG) delivery system possessing intrinsic adjuvant properties and capable of simultaneously delivering multiple antigens to the immune system. Such a flexible delivery system can produce an effective vaccine that will prevent the development of trachomatous conjunctivitis and blindness. The safety and relatively cheap production cost of BG-based vaccines offer a technological and manufacturing advantage for a vaccine needed on a global scale.     

Chitosan as a novel nasal delivery system for vaccines

A variety of different types of nasal vaccine systems has been described to include cholera toxin, microspheres, nanoparticles, liposomes, attenuated virus and cells and outer membrane proteins (proteosomes). The present review describes our work on the use of the cationic polysaccharide, chitosan as a delivery system for nasally administered vaccines. Several animal studies have been carried out on influenza, pertussis and diphtheria vaccines with good results. After nasal administration of the chitosan-antigen nasal vaccines it was generally found that the nasal formulation induced significant serum IgG responses similar to and secretory IgA levels superior to what was induced by a parenteral administration of the vaccine. Animals vaccinated via the nasal route with the various chitosan-antigen vaccines were also found to be protected against the appropriate challenge. So far the nasal chitosan vaccine delivery system has been tested for vaccination against influenza in human subjects. The results of the study showed that the nasal chitosan influenza vaccine was both effective and protective according to the CPMP requirements. The mechanism of action of the chitosan nasal vaccine delivery system is also discussed.     

Nanostructured lipid carriers as novel drug delivery system for lung cancer gene therapy

Context: Nanostructured lipid carriers (NLC) are potentially good colloidal drug carriers for gene delivery. They are advised to be the second lifetime of lipid nanocarriers.

Objective: The aim of this study is to develop novel modified NLC as nanomedicine for delivery of plasmid-containing enhanced green fluorescence protein (pEGFP). This system could target the lung cancer cells through receptor-mediated pathways to increase the nuclear uptake of genetic materials.

Methods: In the present study, pEGFP-loaded NLC (NLC/pEGFP) were prepared. Transferrin (Tf) containing ligands were used for the surface coating of the vectors. In vitro transfection efficiency of the modified vectors was evaluated in human alveolar adenocarcinoma cell line (A549 cells) and in vivo transfection efficiency of the modified vectors was evaluated on mice bearing A549 cells model.

Results: Tf-modified NLC/pEGFP (Tf-NLC/pEGFP) has a particle size of 157?nm, and ～82% of gene loading quantity. Tf-NLC/pEGFP displayed remarkably higher transfection efficiency than non-modified NLC/pEGFP both in vitro and in vivo.

Conclusion: The results demonstrate that the novel NLC gene delivery system offers an effective strategy for lung cancer gene therapy.     

Delivery of Chlamydia vaccines

The plethora of ocular, genital and respiratory diseases of Chlamydia, including nongonococcal urethritis, cervicitis pelvic inflammatory disease, ectopic pregnancy, tubal factor infertility, conjunctivitis, blinding trachoma and interstitial pneumonia, and chronic diseases that may include atherosclerosis, multiple sclerosis, adult onset asthma and Alzheimer’s disease, still pose a considerable public health challenge to many nations. Although antibiotics are effective against Chlamydia when effectively diagnosed, asymptomatic infections are rampart, making clinical presentation of complications often the first evidence of an infection. Consequently, the current medical opinion is that an effective prophylactic vaccine would constitute the best approach to protect the human population from the most severe consequences of these infections. Clinical and experimental studies have demonstration that Chlamydia immunity in animals and humans is mediated by T cells and a complementary antibody response, and the completion of the genome sequencing of several isolates of Chlamydia is broadening our knowledge of the immunogenic antigens with potential vaccine value. Thus, major advances have been made in defining the essential elements of a potentially effective subunit vaccine design and parameters for evaluation. However, the challenge to develop effective delivery systems and human compatible adjuvants that would boost the immune response to achieve long-lasting protective immunity remains an elusive objective in chlamydial vaccine research. In response to evolving molecular and cellular technologies and novel vaccinology approaches, considerable progress is being made in the construction of novel delivery systems, such as DNA and plasmid expression systems, viral vectors, living and nonliving bacterial delivery systems, the use of chemical adjuvants, lipoprotein constructs and the codelivery of vaccines and specific immuno-modulatory biological agonists targeting receptors for chemokines, Toll-like receptors, and costimulatory molecules. The application of these novel delivery strategies to Chlamydia vaccine design could culminate in timely achievement of an efficacious vaccine.