Basic approach to neuro-replacement therapy: Alzheimer's

本文是对研究课题5的回应。 干细胞最近有报道称，成年人的大脑保留了多能祖细胞，这表明CNS细胞类型的再生可能发生在整个生命过程中。 可植入的人类神经祖细胞（HNP）的可行性已被报道，神经替代疗法越来越多地针对神经退行性疾病。 这些事实促使我们提出我们目前的研究，使用HNP作为阿尔茨海默病（AD）移植治疗的细胞来源。 由于基底前脑胆碱能神经元的缺失可能参与了AD记忆的恶化，因此我们将研究移植HNP对胆碱能神经元的替代。 我们推测移植的HNP会通过胆碱能损伤脑内存在的因子或线索迁移并分化为必需的细胞（胆碱能神经元和胶质细胞）。干细胞通常被定义为自我更新和多能的，具有产生不同类型分化细胞的能力。 神经干细胞样细胞已从胚胎和成年啮齿动物中枢神经系统（CNS）中分离出来，并在多种培养系统中体外增殖。 使用无血清条件，我们已经能够在体外扩增HNP而不失去其多能性，这提供了一种良好表征的有效的可移植材料来源，作为使用人胎儿神经元组织的有利替代方案。 最近，我们成功地使用这些体外扩增的HNP细胞移植来改善老年大鼠的认知功能。 在我们的研究中，BrdU标记的细胞根据宿主脑的环境线索迁移到各种脑区并分化成各种细胞。在目前的建议中，我们将采用相同的策略，在体外扩增和移植程序中使用的HNP在以前的研究，建立良好的基础胆碱能神经元病变模型。 我们将通过Morris水迷宫分析移植动物的认知功能，并通过免疫荧光组织化学多重标记分析HNPs的迁移和分化。这项拟议的研究将为我们未来的资助提案奠定基础，该提案涉及表征和操纵宿主大脑释放的因子，以了解神经退行性疾病条件下HNP的必要分化条件。 这一系列研究将极大地促进在AD的治疗策略中从HNP移植和/或产生CNS表型。

This proposal is to respond the research topic 5. Stem Cells. It has recently been reported that the adult human brain retains multipotent progenitors, suggesting that regeneration of CNS cell types may occur throughout life. The feasibility of engraftable human neural progenitor (HNPs) has been reported and neuroreplacement therapies are increasingly targeting neurodegenerative diseases. These facts stimulate us to propose our current study, using HNPs as a source of cells for transplantation therapy in Alzheimer's disease (AD). Since the loss of basal forebrain cholinergic neurons may involved in the deterioration of memory in AD, we will investigate the replacement of the cholinergic cells by engrafted HNPs. We hypothesized that transplanted HNPs will migrate and differentiate into the necessary cells (cholinergic neurons and glial cells) by the factor or cue existing in the brain with cholinergic lesion. Stem cells are often defined as self-renewing and multipotent, with the capacity to generate diverse types of differentiated cells. Neural stem-like cells have been isolated from the embryonic and adult rodent central nervous system (CNS) and propagated in vitro in a variety of culture systems. Using serum-free condition, we have been able to expand HNPs in vitro without losing its multipotency, which offers a well-characterized and effective source of transplantable material as a favorable alternative to using human fetal neuronal tissues. We recently succeeded in the improvement of cognitive function of aged rats using the transplantation of these in vitro expanded HNPs cells. In our study the cells, which labeled with BrdU, migrated into wide variety of the brain region and differentiated into a various kinds of cells according to the environmental cue of the host brain. In this current proposal, we will apply same strategy for in vitro expansion and transplantation procedure of the HNPs used in the previous study to well established basal cholinergic neuronal lesion models. We will analyze the cognitive function of transplanted animals by Morris water maze, and the migration and differentiation of HNPs by multiple labelings of immunofluorescent histochemistry. This proposed study will build a base of our future grant proposal, which involves characterization and manipulation of the factors released from the host brains to understand the requisite differentiation conditions of HNPs under neurodegenerative condition. This line of studies will greatly facilitate the transplantation and/ or generation of CNS phenotypes from HNPs in therapeutic strategies for AD.