Enhancing function of grafted primate dopamine neurons

项目2.增强移植的灵长类多巴胺神经元的功能 使用神经营养因子 绝大多数移植的多巴胺神经元在最初几天内死亡，似乎限制了这种治疗帕金森病的策略的成功。成人帕金森病患者大脑中关键生长因子的不足可能是早期细胞死亡和纹状体移植物生长受限的主要原因。该项目提出研究，以确定慢性递送的神经营养因子是否可以增加胎儿中脑多巴胺神经元的存活和生长，并改善帕金森病灵长类动物神经移植的生化和功能结果。测试的因素将包括胶质细胞系衍生神经营养因子(GDNF)，由大胶囊细胞以生物方式递送。胎儿纹状体除了释放GDNF外，还会释放多种神经营养因子，这种环境为多巴胺神经元的正常发育提供了关键的支持。因此， 富含少突胶质细胞-2型星形胶质细胞(SO2A)前体细胞的胎儿纹状体释放的因子也将对多巴胺神经元的存活进行研究。实验将利用植入GDNF释放胶囊，或在MPTP治疗的猴子尾状体内植入腹侧中脑移植物增加距离的SO2A细胞共移植，这是一个再现帕金森病所有标志性行为特征的模型。对供体组织的明确解剖和预先选择MPTP治疗的猴子将限制研究中的可变性。主要的终点指标将是改善帕金森综合症，与多巴胺神经元存活和胞体大小相关，以及通过生化指标和光学和电子显微镜确定的多巴胺纤维生长。这些研究的方法已经到位，关键的初步研究有力地支持了可行性和假设。这些研究将增加对灵长类胎儿多巴胺神经元与神经营养因子相互作用的理解，并将导致 改进和更可重复性的细胞替代方法，这可能使帕金森氏病患者受益，也可能使其他神经退行性疾病患者受益。

PROJECT 2. ENHANCING FUNCTION OF GRAFTED PRIMATE DOPAMINE NEURONS WITH NEUROTROPHIC FACTORS The death of the vast majority of transplanted dopamine neurons within the first few days appears to limit the success of this treatment strategy for Parkinson's disease. The inadequacy of critical growth factors in the adult parkinsonian brain may be a major cause of early cell death and restricted outgrowth of grafts placed into the striatum. This project proposes studies to determine whether chronically delivered neurotrophic factors can increase the survival and outgrowth of fetal mesencephatic dopamine neurons, and improve the biochemical and functional outcome of neural grafting in parkinsonian primates. Factors tested will include glial cell line-derived neurotrophic factor (GDNF), delivered biologically by macroencapsulated cells. Fetal striatum releases several neurotrophic factors besides GDNF, and this milieu provides critical support to dopamine neurons during their normal development. Thus, the effect of factors released from fetal striatum enriched in oligodendrocyte-type-2 astrocyte (SO2A) progenitor cells will also be investigated on dopamine neuron survival. Experiments will utilize implantation of GDNF-releasing capsules, or cografting of SO2A cells at increasing distances from ventral mesencephalic grafts placed into the caudate in the MPTP-treated monkey, a model that reproduces all the hallmark behavioral features of Parkinson's disease. Defined dissections of donor tissue and pre-selection of MPTP-treated monkeys will limit variability in the studies. The main end-point measures will be improvement in parkinsonism, correlated with dopamine neuron survival and soma size, and dopamine fiber outgrowth, determined by biochemical measures and light and electron microscopy. Methods for these studies are in place, and key pilot studies strongly support feasibility and the hypotheses. These studies will increase understanding of the interaction of primate fetal dopamine neurons with neurotrophic factors, and will lead to improved and more reproducible methods of cellular replacement which may benefit patients with Parkinson's disease and possibly other neurodegenerative disorders.