The Role of Neural Stem Cells in Traumatic Brain Injury

描述（由申请人提供）：创伤性脑损伤（TBI）是儿童和成人中最常见的获得性脑损伤类型。迄今为止，我们对创伤性脑损伤的病理和治疗的大部分见解都集中在创伤后发生的区域生理学上。然而，我们对这种损伤在细胞和分子水平上发生了什么了解有限。最近，内源性神经干细胞被认为与各种类型脑损伤后发生的细胞重塑有关。我们最近用小鼠创伤性脑损伤模型证明，神经干细胞增殖、迁移并帮助重塑脑损伤区域。然而，目前尚不清楚神经干细胞对这种重塑有多少贡献，以及这种贡献是否以功能上有用的方式发生。本研究将在小鼠海马中建立TBI分子模型，以确定内源性神经干细胞在损伤后海马恢复中的作用。在特异性目标1中，我们将量化TBI后海马干细胞增殖的大小和时间过程。我们将使用一种转基因动物来实现这一目标，我们已经开发并鉴定了这种动物在成年神经祖细胞中只表达绿色荧光蛋白。在特异性目标2中，我们将确定创伤性脑损伤后的功能恢复是否取决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进行功能获得和功能丧失研究。这些包括上面提到的巢蛋白rtta - gfp小鼠，以及Bax缺陷小鼠，在损伤后具有神经保护和丰富的神经干细胞。最后，在特异性目的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。我们将在体外使用器官型海马培养，并在单个神经干细胞中测量钙通量如何受到细胞调节剂（如IP3受体）的影响。

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.