Biomechanical Analysis of Traumatic Brain Injury Models

描述（由申请人提供）：这是一项专注于创伤性脑损伤生物力学的资助的修订竞争性延续。在这一延续应用中，我们研究了海马组织菌株如何转化为细胞菌株，并继续集中研究NMDA受体（NMDAR）的机械敏感性及其在海马神经元死亡中的作用。广泛的长期目标是检查区域神经元群体是否具有“机械易感性”和损伤易感性，测试非突触外和突触NMDAR是否具有不同的机械敏感性，并使用NMDAR机械敏感性数据来评估即时和延迟治疗策略，以减少机械损伤后的神经元死亡。本研究计划的具体目的如下：目的1：描述与损伤相关的真实体内变形的器官型海马培养物中的局部微机械环境。目的2：利用HEK293t细胞和器官型海马培养物中表达的重组NMDAR来测量突触外和突触内NMDAR的机械激活阈值。目的3：研究JNK和ERK在机械敏感性NMDARs中的激活和控制，利用这些信息来研究减少机械损伤后细胞死亡的急性和延迟治疗策略。我们的假设是(a)在相同的组织拉伸水平下，齿状回和CAS中的神经元比其他海马区域经历更高的机械变形，(b) NMDARs由于与细胞骨架的连接而对拉伸敏感，(c)突触外NMDA受体的机械激活将通过STEP影响JNK的激活，(d) ERK的激活将优先由突触NMDARs控制。与STEP活性介导的ERK信号的持续时间有关。相关性：本研究将研究创伤性脑损伤过程中海马神经元的损伤机制。这项工作将集中于研究一种已知在记忆形成和细胞死亡中起作用的受体的机械激活。利用受体激活的信息，研究人员将开发和测试治疗策略，以减少创伤性脑损伤后的神经元死亡。

DESCRIPTION (provided by applicant): This is a revised competing continuation of a grant focusing on the biomechanics of traumatic brain injury. In this continuation application, we study how tissue strains translate to cellular strains in the hippocampus, and proceed to concentrate on the NMDA receptor (NMDAR) mechanosensitivity and its role in hippocampal neuronal death. The broad, long term objective is to examine if regional neuronal populations are 'mechanically vulnerable' and susceptible to injury, to test if extrasynpatic and synpatic NMDARs have different mechanosensitivity, and to use the data on NMDAR mechanosensitivity to evaluate both immediate and delayed treatment strategies to reduce neuronal death after mechanical injury. The specific aims of this research plan are as follows: Aim 1: To describe the local micromechanical environment in organotypic hippocampal cultures subjected to realistic, in vivo deformations associated with injury. Aim 2: To measure the mechanoactivation threshold for extrasynaptic and synaptic NMDAR using recombinant NMDAR expressed in HEK293t cells and organotypic hippocampal cultures. Aim 3: To examine the activation and control of both JNK and ERK from mechanosensitive NMDARs, using this information to examine acute and delayed treatment strategies for reducing cell death after mechanical injury. Our overlying hypotheses are (a) at the same level of tissue stretch, neurons in the dentate gyrus and CAS experience higher mechanical deformations than other hippocampal regions, (b) NMDARs are stretch sensitive due to linkages to the cytoskeleton, (c) the mechanoactivation of extrasynaptic NMDA receptors will influence the activation of JNK through STEP, and (d) ERK activation will be preferentially controlled by synaptic NMDARs, with the duration of ERK signaling mediated by the activity of STEP. Relevance: This work will study how neurons in the hippocampus are injured during traumatic brain injury. The work will concentrate on studying the mechanical activation of a receptor known to play a role in memory formation and cell death. Using the information of receptor activation, the investigators will develop and test treatment strategies to reduce neuronal death following traumatic brain injury.