RNA Nanosystem for Posterior Eye Drug Delivery

RNA纳米技术提供了具有DNA特征的设计简单的分子， 可以用于治疗。然而，RNA纳米技术的一个主要问题是，RNA分子 相对不稳定，例如它们在体内降解和在超低浓度下解离， 局玻璃体内注射是递送大分子治疗剂的最常用方法 用于治疗疾病。反复玻璃体内注射会导致 对眼睛有严重的不良影响。对于小的药物分子，可以使用全身给药，但这种给药方法不适用于小的药物分子。 给药途径因全身毒性而变得复杂。对更有效的药物的需求尚未得到满足 在治疗后眼部疾病中的递送方法。我们最近研究了RNA纳米颗粒 来源于噬菌体phi29 DNA的包装RNA（pRNA）的三向连接（3WJ） 用于眼部药物输送的包装马达。这些纳米颗粒在化学和物理上都是稳定的 并且可以包含具有不同功能的多个模块，例如RNA适体， 报告部分和治疗性siRNA、miRNA或其它化学药物或配体作为亚基，全部在同一个 纳米粒子我们的初步研究表明，pRNA纳米颗粒（pRNA纳米）是 在结膜下给药后，在眼睛中的角膜、视网膜色素上皮和视网膜中的细胞中内化 注射于小鼠体内。这表明结膜下注射pRNA纳米作为有效的免疫抑制剂的潜力。 将基于RNA的治疗剂递送至眼后段细胞的药物递送系统：pRNA 纳米可以克服RNA分子稳定性和后眼递送问题。初步 研究还表明，pRNA纳米颗粒的递送和保留是粒度依赖性的， 存在最佳尺寸范围以将其有效递送至眼睛中的细胞。的目标 目前的项目是（a）确定用于眼部药物递送的最佳pRNA纳米，（B）证明 的pRNA纳米递送治疗剂以治疗后眼部疾病，以及（c）开发一种巩膜外膜 用于延长这些纳米颗粒递送植入系统。不同尺寸和模块的pRNA纳米 将构建亚基并评价有效的眼内递送和治疗效果， 在动物模型中结膜下注射。巩膜外植入物是可再填充的，并且被放置在巩膜上， 结膜下或筋膜下袋以提供纳米颗粒的持续递送。最终目标是 开发一个使用pRNA技术的眼部药物递送平台，用于通过 眼周途径（比玻璃体内注射侵入性更小的方法）。本项目将审查 联合pRNA纳米和巩膜外植入物方法的可行性，以证明这种新的概念 技术.

RNA nanotechnology provides molecules that have the simplicity in design with the characteristics of DNA and can be used in therapies. However, a major problem in RNA nanotechnology is that RNA molecules are relatively unstable such as their degradation in vivo and dissociation at ultra-low concentration after administration. Intravitreal injection is the most common method to deliver macromolecular therapeutic agents to the posterior segment of the eye for the treatments of diseases. Repeated intravitreal injection can cause severe adverse effects to the eye. For small drug molecules, systemic administration can be used but this route of administration is complicated by systemic toxicity. There is an unmet need of a more effective drug delivery method in the treatment of posterior eye diseases. We have recently studied RNA nanoparticles derived from the three-way junction (3WJ) of the packaging RNA (pRNA) of bacteriophage phi29 DNA packaging motor for ocular drug delivery. These nanoparticles are thermodynamically and chemically stable both in vitro and in vivo and can harbor multiple modules with different functionalities such as RNA aptamer, reporter moiety, and therapeutic siRNA, miRNA, or other chemical drugs or ligands as subunits all in the same nanoparticles. Our preliminary studies have shown that the pRNA nanoparticles (pRNA nano) were internalized in the cells in the cornea, retinal pigment epithelium, and retina in the eye after subconjunctival injection in mice in vivo. This suggests the potential of subconjunctival injection of pRNA nano as an efficient drug delivery system of RNA-based therapeutic agents to the cells in the posterior segment of the eye: pRNA nano can overcome both the RNA molecule stability and posterior eye delivery problems. The preliminary studies have also suggested that the delivery and retention of pRNA nano are particle size dependent and the existence of an optimal size range for their effective delivery to the cells in the eye. The objectives of the present project are to (a) determine the optimal pRNA nano for ocular drug delivery, (b) demonstrate the ability of pRNA nano to deliver therapeutic agents to treat posterior eye disease, and (c) develop an episcleral implant system for prolonged delivery of these nanoparticles. pRNA nano of different sizes and module subunits will be constructed and evaluated for effective intraocular delivery and therapeutic effects after subconjunctival injection in animal models. The episcleral implant is refillable and is placed on the sclera in the subconjunctival or sub-Tenon pocket to provide sustained delivery of the nanoparticles. The ultimate goal is to develop a platform of ocular drug delivery using the pRNA technology for nucleotide-based therapies via the periocular route (a less invasive approach than intravitreal injection). The present project will examine the feasibility of the combined pRNA nano and episcleral implant approach for the proof of concept of this new technology.