CNS Radiation Injury: Regeneration via Human ES Cells

描述(申请人提供)：该项目的目标是研究人类胚胎干细胞(HES)来源的寡祖细胞在结构和功能水平上作为放射性脑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ES细胞(NIH批准的品系WA-01和WA-09)高产量地衍生出寡祖细胞，HES衍生的前体细胞在大鼠脑内的存活和分化，以及对辐射对成年大鼠大脑的有害和不可逆影响的定量研究。脑辐射损伤是癌症治疗中的一个重要临床问题，影响到原发和转移性脑肿瘤患者。辐射对大脑的影响通常发生在较晚的时间(辐射后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复杂，但其病理结果以脱髓鞘和随后的脑萎缩为特征。尽管有关组织病理学变化和癌症患者生活质量的可怕损失的大量文献，但作为细胞替代的可能靶点的辐射模型基本上仍未被探索。我们证明，辐射导致循环中的少突胶质细胞祖细胞池耗尽，随后大脑无法取代成熟的髓鞘细胞。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，我们建议解决它们修复中枢神经系统辐射损伤的潜力。我们将纯化寡祖细胞群体，并在照射后的大鼠中进行初步研究，以努力优化照射后移植的细胞数量、迁移、存活和适宜的植入时机。一旦弄清了这些参数，我们将继续对受辐射的大鼠进行长期寡祖细胞或假移植，并对学习、记忆和认知任务进行仔细的行为评估，以及对脑片进行电学研究，以研究跨越胼胝体的传导。我们希望证明HES来源的寡祖细胞在放射后髓鞘形成和组织及行为功能的细胞结构恢复中的作用。该提案将专门使用NIH批准的HES系列：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.