CNS Radiation Injury: Regeneration via Human ES Cells

描述（由申请人提供）：本项目的目标是在结构和功能水平上研究人类胚胎干（hES）细胞衍生的寡祖细胞作为脑辐射损伤恢复性治疗的潜力。该项目基于大量的初步数据，包括从人类胚胎干细胞中高产量衍生的寡祖细胞（NIH批准的WA-01和WA-09系），大鼠脑中he衍生祖细胞的存活和分化，以及辐射对成年大鼠脑的有害和不可逆影响的定量研究。脑辐射损伤是肿瘤治疗中的一个重要临床问题，影响着原发性和转移性脑肿瘤患者。辐射对大脑的影响通常发生在晚些时候（暴露后6-12个月），并导致认知功能不可逆转的恶化。晚期放射损伤的发病机制是复杂的，但病理结果以脱髓鞘和随后的脑萎缩为特征。尽管有大量文献与组织病理学变化和癌症患者生活质量的可怕损失有关，但辐射模型作为细胞替代的可能目标仍然基本上未被探索。我们证明，辐射导致循环少突胶质细胞祖细胞池的衰竭，随后大脑无法替代成熟的髓鞘细胞。我们最近开发了将hES细胞高效分化为寡祖细胞的方案。在这里，我们建议解决他们的潜力修复辐射损伤的中枢神经系统。我们将纯化寡祖细胞群，并在辐照大鼠中进行初步研究，以优化辐照后细胞数量、迁移、存活和移植物放置的有利时机。一旦这些参数被阐明，我们将继续对受辐射大鼠进行长期少祖细胞或假移植物，并对学习、记忆和认知任务进行仔细的行为评估，以及对大脑切片进行电研究，以研究胼胝体的传导。我们希望证明hES衍生的寡祖细胞在放射后髓鞘和组织的细胞结构修复和行为功能中的作用。本提案将专门使用NIH批准的he系：WA-01和WA-09。

DESCRIPTION (provided by applicant): The goal of this project is to investigate the potential of human embryonic stem (hES) cell derived oligoprogenitors as restorative therapy for radiation-induced damage in the brain at the structural and functional levels. The project is based on a substantial body of preliminary data including high yield derivation of oligoprogenitors from human ES cells (NIH approved lines WA-01 and WA-09), survival and differentiation of hES derived progenitors in rat brains, and a quantitative study of the deleterious and irreversible effects of radiation to the adult rat brain. Radiation damage to the brain is a significant clinical problem in cancer management, affecting patients with primary as well as metastatic brain tumors. The effects of radiation to the brain generally occur late (>6-12 months after exposure) and lead to irreversible deterioration in cognitive function. The pathogenesis of late radiation damage is complex, but the pathological outcome is characterized by demyelination and subsequent cerebral atrophy. The radiation model remains essentially unexplored as a possible target for cell replacement despite significant literature pertaining to histopathological changes and the terrible toll on quality of life of the cancer patient. We demonstrate that irradiation results in exhaustion of the cycling oligodendrocyte progenitor pool, with subsequent inability of the brain to replace mature myelinating cells. We have recently developed protocols for the highly efficient differentiation of hES cells into oligoprogenitors. Here we propose to address their potential for repairing radiation damage to the CNS. We will purify the oligoprogenitor populations and perform pilot studies in irradiated rats in an effort to optimize cell numbers, migration, survival and favorable timing of graft placement post irradiation. Once these parameters are elucidated, we will proceed with long term oligoprogenitor or sham grafts in irradiated rats and perform careful behavioral assessments of learning, memory and cognitive tasks, as well electrical studies on brain slices to study conduction across the corpus callosum. We hope to demonstrate the role of hES derived oligoprogenitors in cytoarchitectural restoration of myelination and tissue and behavioral function post radiation. This proposal will use exclusively NIH approved hES lines: WA-01 and WA-09.