Interplay between the host milieu and human neural stem cells in stroke repair

描述(申请人提供)：中风是美国人每年致残的头号原因。目前，除溶栓治疗外，尚无其他治疗方法可治愈中风患者，但应用有限。我们的长期目标是利用人类神经前体细胞作为一种潜在的治疗方法来促进中风患者的功能恢复。我们和其他人已经证明，在某些情况下，神经干/神经前体可以改善啮齿类动物的神经功能。然而，移植的可行性和功能结果在不同的研究中差别很大。我们的总体假设是，hNPC通过分泌营养因子来增强内源性修复机制，从而促进长期功能。包括对营养因子的关注，可以从机制上理解移植的干细胞如何增强内源性修复过程。重要的是，我们不相信细胞整合到宿主大脑回路中会促进恢复。在特定的目标1中，我们确定了移植细胞对几种内源性修复机制的影响以及体内hNPC随时间的变化而表达的营养因子，并将这些现象与功能恢复联系起来。然后，我们在移植前通过控制hNPC中的表达水平来测试特定的因子。在特定的目标2中，我们通过改变卒中后移植的时机来确定最有利于细胞诱导修复的宿主微环境，目的是找到最佳的移植时机。我们还通过调查受hNPC影响的宿主因素以及改变hNPC对来自宿主微环境的迁移和生存信号的敏感性来测试宿主微环境和hNPC之间的相互作用。这些目标将有助于确定中风后移植人类神经前体细胞的最佳时间，并将成功的细胞治疗与中风后内源性修复的关键分子和细胞机制联系起来。移植物的存活和生物学，以及它对宿主修复机制的影响，将通过免疫组织化学进行评估。功能恢复将使用行为测试进行检查。我们在中风研究和细胞疗法(Kelly，2004)、神经干细胞生物学和培养方法(Palmer，2001)、突触发生(Christopherson，2005)、成像(Micheva，2007)和人神经干细胞的遗传操作(Suzuki，2007)方面的专业知识为斯坦福大学开展细胞移植治疗脑损伤的跨学科研究提供了绝佳的机会。公共卫生相关性：中风是美国人每年导致残疾的头号原因，可以提供的治疗方法有限。我们的长期目标是利用人类神经前体细胞(NPC)作为一种潜在的治疗方法来促进中风患者的功能恢复。在这项建议中，我们试图了解神经干细胞如何增强中风后大脑的自然修复过程，以便我们能够在未来增强这些特性。

DESCRIPTION (provided by applicant): Stroke is the number one cause of disability among Americans each year. Currently there is no therapy to cure stroke patients except the thrombolytic treatments, which have limited use. Our long-term goal is to promote functional recovery from stroke using human neural progenitor cells (hNPCs) as a potential therapy. We and others have shown that neural stem/progenitor in some cases can improve neurological function in rodents. However, transplant viability and functional outcome vary widely across studies. Our overall hypothesis is that hNPCs facilitate long-term functional by enhancing endogenous repair mechanisms through secretion of trophic factors. Including a focus on the trophic factors gives a mechanistic understanding of how transplanted stems cells augment endogenous repair processes. Importantly, we do not believe that the cells enhance recovery integrating into the host brain circuitry. In Specific Aim 1, we determine the effect of the transplanted cells on several endogenous repair mechanisms as well as the trophic factors expressed by the hNPCs in vivo over time, and then correlate these phenomena with functional recovery. We then test specific factors by manipulating their expression levels in hNPCs before transplantation. In Specific Aim 2, we determine the host microenvironment that is most conducive to cell-induced repair by varying the timing of transplantation post- stroke, with the goal of finding the optimal time to transplant. We also test the interplay between the host microenvironment and hNPCs by surveying host factors that are affected by hNPCs and also modifying the hNPCs' sensitivity to signals for migration and survival from the host's microenvironment. Together these aims will help identify the optimal time to transplant human neural progenitor cells after stroke and link successful cell therapy with critical molecular and cellular mechanisms that underlie endogenous repair after stroke. Graft survival and biology, and its effect on host repair mechanisms, will be assessed using immunohistochemistry. Functional recovery will be examined using behavioral tests. Our expertise in stroke research and cellular therapies (Kelly, 2004), neural stem cell biology and culture methods (Palmer, 2001), synaptogenesis (Christopherson, 2005), imaging (Micheva, 2007) and genetic manipulation of hNPCs (Suzuki, 2007) provide an excellent opportunity to develop a cross-disciplinary effort to study cell transplants for brain injury at Stanford. PUBLIC HEALTH RELEVANCE: Stroke is the number one cause of disability among Americans each year, and there are limited therapeutic treatments that can be offered. Our long-term goal is to promote functional recovery from stroke using human neural progenitor cells (NPCs) as a potential therapy. In this proposal we seek to understand how the NPCs augment the brain's natural repair processes after stroke so that we can enhance these properties in the future.