To assess the engraftment of hESC-derived photoreceptors and their ability to restore vision in early and advanced stages of Retinitis Pigmentosa.

评估 hESC 来源的光感受器的植入及其在色素性视网膜炎早期和晚期恢复视力的能力。

• 批准号: MR/X001687/1
• 负责人: Majlinda Lako
• 金额: $ 136.17万
• 依托单位: Newcastle University
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=MR%2FX001687%2F1
• 关键词: assess; engraftment; hESC; derived; photoreceptors

The retina is an extension of the central nervous system that lines the back of the eye, transmitting information from our visual world to the brain via the optic nerve. One of the important roles of the retina is to convert light into electrical signals, a process called phototransduction. These electrical signals are subsequently transmitted across retinal networks, eventually generating impulses in the optic nerve that connects the eye to the brain. Once these impulses reach central visual brain areas, they lead to visual perception. The cells responsible for phototransduction are the photoreceptors, the rods (responsible for vision in dim light conditions) and the cones (responsible for colour vision in bright light conditions and for our ability to see sharp details). One of the main causes of blindness is rod/cone malfunction, often due to genetic mutations (hereditary photoreceptor dystrophies). When these cells do not function properly, they gradually degenerate, leading to partial or total and irreversible blindness. There are currently no available preventative treatments or new therapeutic interventions that can successfully hinder disease progression or offer long-term promising outlook for patients suffering from these devastating conditions. Retinitis pigmentosa (RP) is a common form of hereditary photoreceptor dystrophy associated with progressive rod degeneration of the mid-peripheral retina, leading to night blindness and loss of visual acuity. At later stages of the disease, cones degenerate as well, resulting in complete blindness at final disease stages. Therefore, there is a pressing need to develop novel approaches either for photoreceptor replacement or for reactivation of dysfunctional surviving photoreceptor by gene therapy (if performed at early stages of the disease).In our group, we develop artificial retinas (organoids) derived from human pluripotent stem cells (hPSCs). We isolate photoreceptors from these organoids and inject them in retinas with photoreceptor dystrophies, with the goal to achieve integration of these new healthy photoreceptors into the host retina, eventually restoring visual function. We have successfully achieved these goals using a cone-enriched population of photoreceptor precursors in a mouse model of RP, resulting in partial restoration of visual function assessed by behavioural and electrophysiological testing. However, given the prevalence of rod degeneration in RP, our hypothesis is that transplantation of hPSCs-derived rods at early stages may lead to improved rod integration and function, while also protecting cones from degenerating at later stages. In addition, we suggest that a combination of rod and cone transplantation may achieve optimal results at more advanced stages of retinal degeneration.Here we propose to test this hypothesis in a mouse model of RP. We will develop new hPSC lines, which will enable enrichment of cone and rod precursors, each one carrying a genetically encoded fluorescent marker of a different colour for easier identification once engrafted in the host retina. In one set of experiments, we will inject rods alone at early degeneration stages, with the goal of improving their integration into the host retina and protecting cones from later degeneration. In another set of experiments, we will inject a mixed population of rod and cone precursors at later stages of degeneration, to see whether this approach protects cones from ensuing degeneration. Using all the tools we have developed to generate homogenous populations of cone and rod precursors from hPSCs, perform successful cell transplantation and assess vision restoration using behavioural and electrophysiological approaches, this project will provide fundamental knowledge to establish the optimal conditions necessary for successful large-scale engraftment of stem cell-derived healthy photoreceptors to restore sight in devastating photoreceptor dystrophies.

视网膜是位于眼睛后部的中枢神经系统的延伸，通过视神经将视觉世界的信息传递给大脑。视网膜的一个重要功能是将光转换成电信号，这一过程被称为光导。这些电信号随后通过视网膜网络传输，最终在连接眼睛和大脑的视神经中产生脉冲。一旦这些脉冲到达大脑中央视觉区，就会导致视觉感知。负责光传导的细胞是光感受器、视杆细胞（负责昏暗光线下的视觉）和视锥细胞（负责明亮光线下的色彩视觉和我们看到清晰细节的能力）。失明的主要原因之一是视杆/视锥细胞功能障碍，通常是由于基因突变（遗传性光感受器营养不良症）。当这些细胞不能正常工作时，它们逐渐退化，导致部分或全部和不可逆转的失明。目前还没有可用的预防性治疗或新的治疗干预措施能够成功地阻止疾病进展或为患有这些毁灭性疾病的患者提供长期有希望的前景。色素性视网膜炎（RP）是一种常见的遗传性光感受器营养不良，与中周视网膜进行性杆状变性有关，可导致夜盲症和视力丧失。在疾病的晚期，视锥细胞也会退化，导致疾病晚期完全失明。因此，迫切需要开发新的方法来替代光感受器或通过基因治疗重新激活功能失调的存活光感受器（如果在疾病的早期阶段进行）。在我们的团队中，我们开发了来自人类多能干细胞（hPSCs）的人工视网膜（类器官）。我们从这些类器官中分离出光感受器，并将其注射到患有光感受器营养不良的视网膜中，目的是将这些新的健康光感受器整合到宿主视网膜中，最终恢复视觉功能。我们已经成功地实现了这些目标，在RP小鼠模型中使用了富含视锥细胞的光感受器前体，通过行为和电生理测试评估了视觉功能的部分恢复。然而，考虑到RP中杆状细胞变性的普遍性，我们的假设是，在早期阶段移植hpscs衍生的杆状细胞可能会改善杆状细胞的整合和功能，同时也可以保护视锥细胞在后期阶段免于变性。此外，我们建议视杆和视锥结合移植可能在视网膜变性晚期达到最佳效果。在这里，我们建议在RP小鼠模型中验证这一假设。我们将开发新的hPSC系，这将使锥状细胞和杆状细胞前体富集，每个前体都携带不同颜色的遗传编码荧光标记，以便在植入宿主视网膜后更容易识别。在一组实验中，我们将在早期变性阶段单独注射视杆细胞，目的是改善它们与宿主视网膜的整合，并保护视锥细胞免遭后期变性。在另一组实验中，我们将在变性后期注射混合的杆状体和锥体前体，看看这种方法是否能保护锥体免受随后的变性。利用我们开发的所有工具，从人乳头状细胞干细胞中产生同质的锥体和杆状前体群体，进行成功的细胞移植，并使用行为和电生理学方法评估视力恢复，该项目将提供基础知识，为成功大规模植入干细胞衍生的健康光感受器以恢复破坏性光感受器营养不良患者的视力提供必要的最佳条件。

项目成果

Incorporating microglia-like cells in human induced pluripotent stem cell-derived retinal organoids.

• DOI: 10.1111/jcmm.17670
• 发表时间: 2023-02
• 期刊: Journal of cellular and molecular medicine
• 影响因子: 5.3

Deciphering the spatio-temporal transcriptional and chromatin accessibility of human retinal organoid development at the single cell level

在单细胞水平上破译人类视网膜类器官发育的时空转录和染色质可及性

• DOI: 10.1101/2023.07.19.549507
• 发表时间: 2023
• 作者: Dorgau B

Bruch's Membrane: A Key Consideration with Complement-Based Therapies for Age-Related Macular Degeneration.

• DOI: 10.3390/jcm12082870
• 发表时间: 2023-04-14
• 期刊: JOURNAL OF CLINICAL MEDICINE
• 影响因子: 3.9
• 作者: Hammadi, Sarah;Tzoumas, Nikolaos;Ferrara, Mariantonia;Meschede, Ingrid Porpino;Lo, Katharina;Harris, Claire;Lako, Majlinda;Steel, David H.
• 通讯作者: Steel, David H.

Retinal organoids provide unique insights into molecular signatures of inherited retinal disease throughout retinogenesis.

视网膜器官在整个视网膜生成过程中对遗传性视网膜疾病的分子特征提供了独特的见解。

• DOI: 10.1111/joa.13768
• 发表时间: 2023-08
• 期刊: JOURNAL OF ANATOMY
• 影响因子: 2.4
• 作者: Watson, Avril;Lako, Majlinda
• 通讯作者: Lako, Majlinda