Regulation of adult hippocampal function by the neural stem and progenitor cell secretome

成年海马体中一个独特的神经源性小生境拥有神经系干细胞， 在许多成年哺乳动物中的寿命。揭示这些干细胞的功能作用以及它们如何 与壁龛中其他细胞类型的相互作用可以提供对介导海马神经元的机制的深入了解。 认知情感功能，以及成人大脑组织再生的潜在机制。 最近，干细胞分泌蛋白（即干细胞分泌组）已成为组织中有影响力的参与者 体内平衡然而，对于细胞分泌蛋白的含量和功能知之甚少。 内源性神经干细胞及其祖细胞（NSPCs）在成年海马。我们的初步数据 表明成年海马NSPCs可能通过产生可溶性的 蛋白质，血管内皮生长因子（VEGF）。我们发现，NSPCs合成大量的VEGF， 它们的海马生态位和NSPC衍生的VEGF是维持健康海马功能所必需的。 我们建议研究NSPCs通过VEGF的直接作用支持海马功能的假设 抑制神经元过度兴奋，最终支持记忆功能，以及保护它免受 损伤在目标1中，我们将使用RNA测序以及遗传密码扩展，再加上双正交非 典型的氨基酸蛋白标记，以确定NSPCs对VEGF亚型的特异性局部贡献 在这些细胞所在的齿状回亚区的细胞层中。在目标2中，我们将使用转基因 敲低和病毒拯救模型，以研究齿状回回路活动是如何被特异性调节的， NSPC衍生的VEGF。在目标3中，我们将使用转基因敲除和病毒拯救模型来确定如何 NSPC-VEGF影响海马行为功能和对兴奋性毒性损伤的脆弱性。完成 这项工作的一部分将通过内源性NSPCs的分泌组建立一个新的功能维度， 了解海马健康是如何积极维持在一个独特的利基成人大脑。

A unique neurogenic niche in the adult hippocampus hosts neural-lineage stem cells that can persist throughout the lifespan in a wide range of adult mammals. Uncovering the functional role of these stem cells and how they interact with other cell types in the niche can provide insight in to the mechanisms that mediate hippocampal cognitive-emotional functions, as well as potential mechanisms for regenerating tissue in the adult brain. Recently, stem cell secreted proteins (i.e. the stem cell secretome) have emerged as influential players in tissue homeostasis. However, relatively little is known about either the content or the function of the secretome of endogenous neural stem cells and their progenitors (NSPCs) in the adult hippocampus. Our preliminary data reveal that adult hippocampal NSPCs may regulate their microenvironment through the production of the soluble protein, vascular endothelial growth factor (VEGF). We find that NSPCs synthesize large quantities of VEGF in their hippocampal niche and that NSPC-derived VEGF is necessary for sustaining healthy hippocampal function. We propose to investigate the hypothesis that NSPCs support hippocampal function by direct actions of VEGF that suppress neuronal hyperexcitability, ultimately supporting memory function, as well as protecting it from injury. In Aim 1, we will use RNAsequencing as well as genetic code expansion coupled with biorthogonal non- canonical amino acid protein tagging to determine the specific local contributions of NSPCs to VEGF isoforms in the cell layers of the dentate gyrus subregion where these cells reside. In Aim 2, we will use transgenic knockdown and viral rescue models to investigate how dentate gyrus circuit activity is regulated specifically by NSPC-derived VEGF. In Aim 3, we will use transgenic knockdown and viral rescue models to determine how NSPC-VEGF influences hippocampal behavioral functions and vulnerability to excitotoxic injury. The completion of this work will establish a new functional dimension of endogenous NSPCs via their secretome, and advance understanding of how hippocampal health is actively maintained in a unique niche of the adult brain.