Sudharsan Raghavi, Dolgova Natalia, Kwok Jennifer, Gray Alexa, Sato Yu, Madrigal Agustin Luz, Susaimanickam Praveen Joseph, Kriukov Emil, Baranov Petr, Wolfe John H, Aguirre Gustavo D, Gamm David M, Beltran William A
Division of Experimental Retinal Therapies, Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.
Waisman Center, University of Wisconsin-Madison, Madison, WI, 53705, USA.
Stem Cell Res Ther. 2025 Jul 25;16(1):397. doi: 10.1186/s13287-025-04509-w.
Progressive photoreceptor loss in retinal degenerative diseases leads to irreversible vision impairment. Transplantation of human embryonic or induced pluripotent stem cell-derived photoreceptor precursor cells (PRPCs) offers potential for vision restoration. However, substantial early donor cell loss remains a major challenge. This study aims to elucidate the mechanisms underlying early PRPC loss and to evaluate host retinal responses to transplantation.
PRPCs derived from human embryonic stem cells (hESC)-based retinal organoids were subretinally transplanted into both normal and degenerated canine retinas to investigate the impact of host retinal degeneration on transplant survival and integration. Single-cell RNA sequencing (scRNAseq) was performed on transplanted PRPCs 3 days post-transplantation into normal canine retinas, as well as on host retinal cells to identify molecular pathways associated with early donor cell loss. Non-invasive multimodal retinal imaging and immunohistochemical analyses were conducted to assess PRPC survival, integration, and host immune responses.
Despite systemic immunosuppression, extensive early loss of human PRPCs occurred within the first week following xenotransplantation into both normal and degenerated canine retinas, suggesting that factors beyond immune activation contribute to donor cell loss. Transcriptomic analysis identified metabolic stress as a key driver of early donor cell death, characterized by dysregulation of mitochondrial function and oxidative phosphorylation pathways. Microglial infiltration into the donor cell mass was also observed in normal retinas, suggesting a response to donor cell stress and apoptosis. Beyond the initial phase of cell death, surviving donor cells integrated and persisted when transplanted into retinas with a partially preserved outer nuclear layer, whereas cell loss continued when intervention occurred at end-stage degeneration.
Metabolic stress represents a critical barrier to PRPC survival following transplantation. Strategies aimed at enhancing metabolic resilience may improve transplantation outcomes. Furthermore, host retinal responses shape the transplant microenvironment, influencing donor cell survival and integration. These findings highlight the need for targeted interventions to mitigate early metabolic stress and optimize PRPC transplantation strategies for retinal degenerative diseases.
视网膜退行性疾病中感光细胞的渐进性丧失会导致不可逆的视力损害。移植人胚胎或诱导多能干细胞来源的感光细胞前体细胞（PRPCs）为视力恢复提供了可能。然而，早期供体细胞大量损失仍是一个主要挑战。本研究旨在阐明早期PRPC损失的潜在机制，并评估宿主视网膜对移植的反应。
将源自人胚胎干细胞（hESC）的视网膜类器官的PRPCs经视网膜下移植到正常和退化的犬视网膜中，以研究宿主视网膜退化对移植存活和整合的影响。在将PRPCs移植到正常犬视网膜3天后，对移植的PRPCs以及宿主视网膜细胞进行单细胞RNA测序（scRNAseq），以确定与早期供体细胞损失相关的分子途径。进行非侵入性多模态视网膜成像和免疫组织化学分析，以评估PRPC的存活、整合和宿主免疫反应。
尽管进行了全身免疫抑制，但在异种移植到正常和退化的犬视网膜后的第一周内，人PRPCs仍出现大量早期损失，这表明免疫激活以外的因素导致了供体细胞损失。转录组分析确定代谢应激是早期供体细胞死亡的关键驱动因素，其特征是线粒体功能和氧化磷酸化途径失调。在正常视网膜中也观察到小胶质细胞浸润到供体细胞团中，表明对供体细胞应激和凋亡有反应。在细胞死亡的初始阶段之后，当移植到外核层部分保留的视网膜中时，存活的供体细胞会整合并持续存在，而在终末期退化时进行干预则细胞损失会继续。
代谢应激是移植后PRPC存活的关键障碍。旨在增强代谢恢复力的策略可能会改善移植结果。此外，宿主视网膜反应塑造了移植微环境，影响供体细胞的存活和整合。这些发现凸显了采取针对性干预措施以减轻早期代谢应激并优化视网膜退行性疾病PRPC移植策略的必要性。
