Retinal disease models for translational photoreceptor replacement

神经性视网膜或视网膜色素上皮(RPE)的疾病会导致大量的视力障碍，其中许多会导致感光细胞的退化和死亡。许多自然发生的遗传性视网膜变性(RD)疾病已被鉴定为人类疾病的真正同源物。我们的研究团队一直在帮助证明AAV介导的视网膜基因治疗在疾病模型中的翻译连续体中发挥着关键作用，因为它允许对视网膜基因治疗的治疗反应和长期结果进行快速、经济有效和临床相关的评估。然而，先前的基因治疗试验的成功依赖于活的、尽管是有病的靶细胞的存在。相反，晚期RD的靶细胞的大量丢失将需要允许光感受器细胞再生或替换以及恢复神经连接的治疗策略。人类视网膜疾病的模型可以提供光感受器替代疗法改善视觉功能所需的基础知识，正如AGI RFA所规定的那样。我们组建了一支研究团队，他们在神经前体细胞和多能干细胞生物学、视网膜细胞分化、遗传性视网膜疾病病理和治疗以及实验性RD治疗的功能分析方面具有专业知识。研究人员拥有评估治疗反应和制定适当结果措施以评估安全性和有效性的专业知识。我们有专门的视网膜疾病研究设施来评估人类视网膜疾病的模型。 我们的目标是开发模型，研究疾病条件下光感受器的替换。这些模型将被用来确定细胞移植、植入和分化的关键参数，这些参数对于研究视网膜再生医学的疾病特异性应用至关重要。需要研究的关键特性包括物理移植参数、供体细胞在宿主视网膜内的分布、供体细胞的分化和存活、视网膜内细胞的连接和功能、与大脑中视觉通路的连接和中枢神经系统的处理，以及视觉的行为分析。移植参数将使用异种移植进行研究，异种移植来自两个特征良好且容易获得的人类多能干细胞报告系，它们标记视锥和视杆或仅标记视杆。同时，我们将开发一个用于光感受器替换的物种内系统，通过生产等效的IPSC和视锥/视杆和仅视杆的IPSC报告系来替换视网膜光感受器细胞，以概括将发生在使用人类细胞的人类临床试验中的植入。一旦开发出来，将在疾病模型中分析光感受器前体细胞移植的整合和功能，在该模型中，可以评估分化为新的视杆细胞和视锥细胞。

Diseases of the neural retina or retinal pigment epithelium (RPE) cause a substantial number of sight-impairing disorders, many of which lead to the degeneration and death of photoreceptor cells. A number of naturally occurring inherited retinal degeneration (RD) diseases have been identified that are true homologues of human diseases. Our research team has been instrumental in demonstrating that AAV-mediated gene therapy for the retina in disease models plays a critical role in the translational continuum by permitting a rapid, cost-effective, and clinically relevant assessment of therapeutic responses and long-term outcomes of retinal gene therapy. However, the success of prior gene therapy trials depended on the presence of viable, albeit diseased, target cells. In contrast, the substantial loss of target cells in advanced RD will require therapeutic strategies that permit regeneration or replacement of photoreceptor cells and restoration of neural connectivity. Models of human retinal diseases can provide the foundational knowledge needed for photoreceptor replacement therapies to improve visual function, as specified in the AGI RFA. We have assembled a team of investigators with expertise in neural progenitor and pluripotent stem cell biology, retinal cell differentiation, inherited retinal disease pathology and therapy, and functional analysis of experimental RD treatments. The investigators have the expertise to assess therapeutic responses and to develop appropriate outcome measures to evaluate safety and efficacy. We have a dedicated retinal disease research facility to assess models of human retinal disorders. Our goal is to develop models in which to investigate the replacement of photoreceptors under disease conditions. The models will be used to identify key parameters of cell transplantation, engraftment, and differentiation that will be critical for studies of disease-specific applications of regenerative medicine for the retina. Key properties to be studied are physical transplantation parameters, distribution of donor cells within the host retina, donor cell differentiation and survival, cell connectivity and functionality within the retina, connectivity to the visual pathways in the brain and CNS processing, and behavioral assays for vision. Transplantation parameters will be studied using xenografts derived from two well-characterized and readily available human pluripotent stem cell reporter lines that label cones and rods or only rods. Concurrently, we will develop a within-species system for photoreceptor replacement by producing equivalent iPSCs and cone/rod and rod-only iPSC reporter lines for replacement of retinal photoreceptor cells to recapitulate the engraftment that would occur in human clinical trials using human cells. Once developed, the photoreceptor precursor cell transplants will be analyzed for integration and functionality in disease models in which differentiation into new rod and cone visual cells can be evaluated.