Delivery of LEDGF for retinal degenerative disorders

描述（由申请人提供）：与视网膜变性疾病（如视网膜色素变性、黄斑变性和Usher综合征）相关的光感受器丧失是人类失明的主要原因。光凝和玻璃体内VEGF适体是视网膜变性疾病的唯一治疗选择，在大多数视网膜变性患者中价值有限，并且不特异性靶向光感受器的拯救。因此，迫切需要一种能够减少光感受器变性的药理学方法，这是本提案的焦点。治疗视网膜变性疾病的合理方法是开发能够促进感光细胞存活的治疗剂。在过去的十年中，透镜上皮衍生生长因子（LEDGF）被鉴定、表征，并被证明是感光细胞、视网膜色素上皮细胞和其他细胞类型抵抗多种应激的存活因子。最重要的是，玻璃体内注射LEDGF已经挽救了光损伤的Sprague-Dawley大鼠和RCS大鼠中的感光细胞，表明LEDGF的治疗潜力。由于视网膜退行性疾病的治疗可能是慢性的，并且因为重复的玻璃体内注射可能导致并发症，如白内障、眼内炎和视网膜脱离，我们建议开发一种用于持续视网膜递送LEDGF的经巩膜方法，并获得该方法有效性的证据。本研究的目的是为以下假设的原理提供证据：结膜下施用的微粒形式的LEDGF以持续的方式到达视网膜，并减少S334 ter-4和RCS-p+大鼠模型中持续视网膜变性的光感受器损失。这一假设将通过以下两个具体目标进行检验。1)确定纳米多孔LEDGF-PLGA微粒是否维持LEDGF释放。2)确定结膜下给药后大鼠中纳米多孔LEDGF-PLGA微粒是否维持视网膜LEDGF递送并减少感光细胞损失。本研究将利用超临界流体技术来控制微粒中的颗粒孔隙率、LEDGF释放和残留溶剂含量，并利用免疫化学方法来评估视网膜LEDGF递送。此外，将在视网膜变性的大鼠模型中确定这种LEDGF递送模式对视网膜ERG、存活的感光细胞数量和视网膜组织学的影响。与视网膜变性疾病如视网膜色素变性、黄斑变性和Usher综合征相关的感光器损失是人类失明的主要原因。光凝和玻璃体内VEGF适体是视网膜变性疾病的唯一治疗选择，在大多数视网膜变性患者中价值有限，并且不特异性靶向光感受器的拯救。因此，迫切需要一种能够减少光感受器变性的药理学方法，这是本提案的焦点。

DESCRIPTION (provided by applicant): Photoreceptor loss associated with retinal degenerative disorders such as retinitis pigmentosa, macular degeneration, and Usher's syndrome is a leading cause of blindness in humans. Photocoagulation and intravitreal VEGF aptamer, the only treatment options for retinal degenerative disorders, are of limited value in majority of the retinal degeneration patients, and do not specifically target the rescue of photoreceptors. Thus, there is a pressing need for a pharmacological approach capable of reducing photoreceptor degeneration, which is the focus of this proposal. A logical approach to treat retinal degenerative disorders would be to develop therapeutic agents capable of promoting photoreceptor survival. During the last decade, lens epithelium-derived growth factor (LEDGF) was identified, characterized, and demonstrated to be a survival factor for photoreceptor cells, retinal pigment epithelial cells, and other cell types against multiple stresses. Most importantly, intravitreal injections of LEDGF have rescued photoreceptor cells in light-damaged Sprague-Dawley rats and RCS rats, indicating the therapeutic potential of LEDGF. Since the therapy for retinal degenerative disorders will likely be chronic and because repeated intravitreal injections can cause complications such as cataracts, endophthalmitis, and retinal detachment, we propose to develop a transscleral approach for the sustained retinal delivery of LEDGF and obtain evidence for the effectiveness of this approach. The objective of this study is to provide proof of the principle for the hypothesis that subconjunctivally administered LEDGF in the form of microparticles reaches the retina in a sustained manner and reduces photoreceptor loss in S334ter-4 and RCS-p+ rat models for sustained retinal degeneration. This hypothesis will be tested using the following two specific aims. 1) To determine whether nanoporous LEDGF-PLGA microparticles sustain LEDGF release. 2) To determine whether nanoporous LEDGF-PLGA microparticles sustain retinal LEDGF delivery and reduce photoreceptor loss in rats following subconjunctival administration. This study will utilize supercritical fluid technology for controlling particle porosity, LEDGF release, and residual solvent content in microparticles and immunochemical methods for assessing retinal LEDGF delivery. In addition, the effect of this mode of LEDGF delivery on retinal ERGs, number of surviving photoreceptor cells, and retinal histology will be determined in the rat models for retinal degeneration. Photoreceptor loss associated with retinal degenerative disorders such as retinitis pigmentosa, macular degeneration, and Usher's syndrome is a leading cause of blindness in humans. Photocoagulation and intravitreal VEGF aptamer, the only treatment options for retinal degenerative disorders, are of limited value in majority of the retinal degeneration patients, and do not specifically target the rescue of photoreceptors. Thus, there is a pressing need for a pharmacological approach capable of reducing photoreceptor degeneration, which is the focus of this proposal.