Delivery of LEDGF for retinal degenerative disorders

描述(申请人提供)：与视网膜退行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。光凝和玻璃体内血管内皮生长因子适配子是治疗视网膜退行性疾病的唯一选择，在大多数视网膜退行性疾病患者中价值有限，并且不专门针对光感受器的挽救。因此，迫切需要一种能够减少光感受器退化的药理学方法，这是本提案的重点。治疗视网膜退行性疾病的合乎逻辑的方法是开发能够促进光感受器存活的治疗剂。在过去的十年中，晶状体上皮源性生长因子(LEDGF)被鉴定、表征，并被证明是光感受器细胞、视网膜色素上皮细胞和其他类型的细胞在多重应激下的生存因子。最重要的是，玻璃体内注射LEDGF挽救了光损伤的SD大鼠和RCS大鼠的光感受器细胞，表明了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，而且反复玻璃体内注射可能会导致白内障、眼内炎和视网膜脱离等并发症，我们建议开发一种经巩膜途径持续输送LEDGF，并为这种方法的有效性获得证据。本研究的目的是在S334ter-4和RCS-p+大鼠的持续性视网膜变性模型中，为结膜下注射LEDGF以微粒的形式持续到达视网膜并减少光感受器丢失的假说提供依据。这一假设将通过以下两个具体目标进行检验。1)确定纳米孔LEDGF-PLGA微球是否能维持LEDGF的释放。2)研究纳米多孔LEDGF-PLGA微球在大鼠结膜下给药后是否支持LEDGF的视网膜递送，减少光感受器的丢失。这项研究将利用超临界流体技术来控制微粒的孔隙率、LEDGF的释放和微粒中的残留溶剂含量，并利用免疫化学方法来评估LEDGF在视网膜的释放。此外，这种LEDGF给药方式对视网膜ERG、存活的光感受器细胞数量和视网膜组织学的影响将在视网膜变性的大鼠模型中确定。与视网膜退行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丢失是导致人类失明的主要原因。光凝和玻璃体内血管内皮生长因子适配子是治疗视网膜退行性疾病的唯一选择，在大多数视网膜退行性疾病患者中价值有限，并且不专门针对光感受器的挽救。因此，迫切需要一种能够减少光感受器退化的药理学方法，这是本提案的重点。

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.