The Role of Neural Stem Cells in Traumatic Brain Injury

描述(申请人提供)：创伤性脑损伤(TBI)是儿童和成人最常见的获得性脑损伤类型。到目前为止，我们对脑外伤的病理和治疗的大部分见解都集中在创伤后发生的局部生理学上。然而，我们对这种损伤后在细胞和分子水平上发生的事情的了解是有限的。近年来，内源性神经干细胞参与了各种类型脑损伤后的细胞重塑。最近，我们利用脑外伤的小鼠模型证明了神经干细胞的增殖、迁移和帮助重塑大脑受损区域。然而，目前还不清楚神经干细胞对这种重塑有多大贡献，以及这种贡献是否以一种功能上有用的方式发生。这项建议将重点放在小鼠海马区的分子模型上，以确定内源性神经干细胞在海马区损伤后恢复中的作用。在具体目标1中，我们将量化脑损伤后海马区干细胞增殖的幅度和时间进程。我们将使用我们开发并鉴定的转基因动物来实现这一点，该转基因动物仅在成年神经前体细胞中表达GFP。在特定的目标2中，我们将确定脑外伤后的功能恢复是否依赖于海马干细胞的增殖。我们将使用我们最近开发的小鼠遗传模型的功能获得和丧失研究来做到这一点。这些小鼠包括上面提到的Nestin-RTTA-GFP小鼠，以及Bax缺陷小鼠，这种小鼠在受伤后受到神经保护，并拥有丰富的神经干细胞。最后，在特定的目标3中，我们将确定细胞内钙如何影响海马神经干细胞的存活。我们将使用器官型海马区培养物在体外进行这项工作，并通过在单个神经干细胞中测量细胞调节因子(如IP3受体)如何影响钙流。 后天脑损伤，如由创伤造成的脑损伤，是所有年龄段最常见的死亡和长期残疾原因之一。目前尚不清楚神经干细胞是否对此类损伤后自发发生的有限恢复负有部分责任。在这项提案中，我们不仅将定义干细胞在创伤性脑损伤后恢复中所起的作用，而且还将确定如何操纵这些细胞来促进损伤后的恢复。

DESCRIPTION (provided by applicant): Traumatic brain injury (TBI) is the most common type of acquired brain injury in both children and adults. To date, most of our insight into the pathology and treatment of TBI has focused on the regional physiology that occurs following trauma. Our knowledge about what happens at the cellular and molecular level following such injuries, however, is limited. Recently, endogenous neural stem cells have been implicated in the cellular remodeling that occurs following various types of brain injury. We recently demonstrated, using a mouse model of TBI, that neural stem cells proliferate, migrate to, and help remodel injured areas of the brain. It is still unclear, however, how much neural stem cells contribute to this remodeling and whether this contribution occurs in a functionally useful way. This proposal will focus on molecularly modeling TBI in the mouse hippocampus in order to determine the role of endogenous neural stem cells on hippocampal recovery after injury. In Specific Aim 1, we will quantify the magnitude and time course of stem cell proliferation in the hippocampus following TBI. We will do this using a transgenic animal that we have developed and characterized that expresses GFP exclusively in adult neural progenitor cells. In Specific Aim 2, we will determine whether functional recovery following TBI depends on hippocampal stem cell proliferation. We will do this using gain- and loss-of-function studies with mouse genetic models that we have recently developed. These include the nestin-rtTA-GFP mouse referenced above as well a Bax- deficient mouse that is neuroprotected following injury and has an abundance of neural stem cells. Finally, in Specific Aim 3, we will determine how intracellular calcium affects the survival of hippocampal neural stem cells. We will do this ex-vivo using organotypic hippocampal cultures and by measuring in individual neural stem cells how calcium flux is affected by cellular regulators such as the IP3 receptor. Acquired brain injuries, such as those resulting from trauma, are among the most common causes death and long-term disability in all age groups. It is unclear whether neural stem cells are responsible for some of the limited recovery that spontaneously occurs following such injuries. In this proposal, we will not only define the role that stem cells play in recovery following traumatic brain injury, but also identify how these cells might be manipulated to improve recovery after injury.