Enhancing function of grafted primate dopamine neurons

项目2.移植灵长类多巴胺神经元的功能增强 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，这似乎限制了帕金森病治疗策略的成功。成年帕金森病患者脑内关键生长因子的不足可能是早期细胞死亡和植入纹状体的移植物生长受限的主要原因。该项目提出的研究，以确定是否长期交付的神经营养因子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源性神经营养因子（GDNF），通过大囊化细胞生物传递。胎儿纹状体除了GDNF外还释放几种神经营养因子，这种环境为多巴胺神经元的正常发育提供了关键支持。因此， 还将研究从富含少突胶质细胞2型星形胶质细胞（SO2A）祖细胞的胎儿纹状体释放的因子对多巴胺神经元存活的影响。实验将利用GDNF释放胶囊的植入，或SO2A细胞的共移植在距离腹侧中脑移植物越来越远的地方放置在MPTP治疗的猴子的尾状核中，该模型再现了帕金森病的所有标志性行为特征。供体组织的明确解剖和MPTP处理猴的预先选择将限制研究中的变异性。主要终点指标是帕金森综合征的改善，与多巴胺神经元存活和索马大小以及多巴胺纤维生长相关，通过生化指标和光学和电子显微镜测定。这些研究的方法已经到位，关键的试点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， 涉及改进的和更可重复的细胞替代方法，其可有益于患有帕金森病和可能的其它神经变性疾病的患者。

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.