Interphotoreceptor Matrix Based Cell Delivery Vehicle for Retinal Regeneration

描述（由申请人提供）：在该项目中，将开发和测试用于将视网膜祖细胞（RPC）递送至视网膜下腔的基于天然基质的细胞递送载体，为视网膜再生提供新的治疗策略。具体地，感光器间基质（IPM），即围绕视杆和视锥感光器的外节并占据感光器和视网膜色素上皮之间的空间的专门基质，将用作细胞递送载体的基础材料。IPM的发育年龄和去除抑制神经再生的分子（硫酸软骨素蛋白聚糖）将被探索为创造促进种子细胞迁移、整合到宿主视网膜和分化的环境的关键因素。最近，将RPC植入视网膜下腔显示出作为能够恢复视功能的治疗的巨大前景。然而，这种疗法成功的主要障碍包括极低水平（<1%）的细胞整合到宿主视网膜中和高水平的植入细胞死亡。一种有前途的方法是使用合成聚合物作为植入的细胞-聚合物复合材料的支架;这些材料使细胞存活率提高了16倍，但水平仍然很低。假设由天然IPM提供的精确的结构和生化线索将促进种子RPC整合到宿主视网膜中、视网膜再生和视觉功能恢复。该项目中开发的细胞递送载体可以为与各种疾病相关的视网膜变性提供可行的临床治疗，包括黄斑变性和早产儿视网膜病变。该项目的具体目标旨在测试中心假设，包括开发和生物化学/结构表征IPM细胞递送载体，测试体外细胞对开发载体的反应，以及测试体内促进视网膜再生和视觉功能的能力。在第一个具体目标中，将开发隔离、处理和表征IPM车辆的程序。IPM将从成年和胎猪眼中分离，经处理以去除残留的细胞物质，经处理以去除硫酸软骨素蛋白聚糖，并进行结构和生化表征。在第二个目标中，将RPC接种到IPM载体上并在视网膜外植体模型中培养。将研究光感受器特异性标记物的附着、增殖、排列、表达以及整合到培养的视网膜中。最后，在目标3中，将有希望的基于IPM的载体用RPC接种并植入小鼠的视网膜下腔。将评估细胞存活、分化、整合到宿主视网膜中以及促进视网膜再生和视觉功能的能力。研究团队拥有跨学科的专业知识，以确保成功实现总体目标，包括一名具有生物材料开发专业知识的化学工程师，一名在细胞聚合物视网膜再生策略方面具有丰富经验的神经科学家，以及一名具有神经再生和干/祖细胞专业知识的神经科学家。 公共卫生相关性：该项目将导致开发一种新型的基于天然基质的细胞递送载体，用于将视网膜祖细胞（RPC）递送到视网膜下腔，以促进患有视网膜病变（包括黄斑变性和早产儿视网膜病变）的患者的视网膜再生和视觉功能恢复。虽然将祖细胞递送至视网膜下空间的策略已经证明了非常有希望的结果，包括一些视力拯救，但成功的主要障碍是低水平的RPC整合（<1%）到宿主视网膜中和高水平的RPC死亡。在这里，由天然感光细胞间基质（IPM）提供的天然结构和生化线索将用于促进RPC存活和整合到相邻的宿主视网膜中。

DESCRIPTION (provided by applicant): In this project, natural matrix-based cell delivery vehicles for retinal progenitor cell (RPC) delivery to the subretinal space will be developed and tested, providing a novel therapeutic strategy for retinal regeneration. Specifically, interphotoreceptor matrix (IPM), the specialized matrix that surrounds the outer segments of rod and cone photoreceptors and occupies the space between the photoreceptors and retinal pigment epithelium, will be used as a base material for cell delivery vehicles. The developmental age of the IPM and removal of molecules inhibitory to neural regeneration (chondroitin sulfate proteoglycans) will be explored as key factors in creating an environment promoting seeded cell migration, integration into host retina, and differentiation. Implantation of RPCs into the subretinal space has recently shown tremendous promise as a therapy capable of restoring visual function. However, major barriers to the success of this therapy include extremely low levels (<1%) of cell integration into host retina and high levels of implanted cell death. A promising approach has been the use of synthetic polymers as scaffolds for cell-polymer composites which are implanted; these materials have resulted in 16-fold enhancement in cell survival, but levels are still inhibitively low. It is hypothesized that precise structural and biochemical cues provided by native IPM will promote integration of seeded RPCs into host retina, retinal regeneration, and restoration of visual function. The cell delivery vehicles developed in this project could provide a feasible clinical treatment for retinal degeneration associated with a wide variety of diseases, including macular degeneration and retinopathy of prematurity. The specific aims of the project, designed to test the central hypothesis, include developing and biochemically/ structurally characterizing IPM based cell delivery vehicles, testing in vitro cellular response to developed vehicles, and testing ability to promote retinal regeneration and visual function in vivo. In the first specific aim, procedures for isolating, processing, and characterizing IPM vehicles will be developed. IPM will be isolated from adult and fetal porcine eyes, processed to remove residual cellular material, treated for removal of chondroitin sulfate proteoglycans, and characterized structurally and biochemically. In the second aim, RPCs will be seeded onto IPM vehicles and cultured in a retinal explants model. The attachment, proliferation, alignment, expression of photoreceptor-specific markers, and integration into cultured retina will be studied. Finally, in aim 3, promising IPM based vehicles will be seeded with RPCs and implanted into the subretinal space of mice. Cell survival, differentiation, integration into host retina, and ability to promote retinal regeneration and visual function will be assessed. The research team has the interdisciplinary expertise essential to ensure success in meeting the overall objective, including a chemical engineer with expertise in biomaterial development, a neuroscientist with extensive experience in cell-polymer retinal regeneration strategies, and a neuroscientist with expertise in neural regeneration and stem/progenitor cells. PUBLIC HEALTH RELEVANCE: This project will result in development of a novel, natural matrix-based cell delivery vehicle for delivery of retinal progenitor cells (RPCs) to the subretinal space to promote retinal regeneration and restoration of visual function in patients suffering from retinopathies including macular degeneration and retinopathy of prematurity. While the strategy of progenitor cell delivery to the subretinal space has demonstrated hugely promising results, including some vision rescue, major barriers to success are low levels of RPC integration (<1%) into host retina and high levels of RPC death. Here, the natural structural and biochemical cues provided by native interphotoreceptor matrix (IPM) will be used to promote RPC survival and integration into adjacent host retina.