SYNAPTIC PLASTICITY AFTER TRAUMATIC BRAIN INJURY

本项目的目的是研究创伤性脑损伤（TBI）后突触修饰和损伤，并提出其在这种情况下的行为和认知改变以及神经元死亡中的可能作用。我们和其他许多人都发现，大鼠脑外伤后LTP受损，行为缺陷出现。尽管从神经生理和行为研究中获得了大量证据，将神经传递的变化与脑损伤后遗症联系起来，但很少有研究涉及突触本身可能的形态、分子和生化改变，这些改变是功能变化和神经元损失的基础。这在一定程度上可能是因为传统的电子显微镜方法不能轻易地检测损伤后突触的形态改变，而用于此类研究的生化和分子生物学方法往往因分析样品中其他亚细胞成分的污染而复杂化。近年来，我们建立了一系列的技术来研究脑损伤后的变化，发现脑缺血后突触的超微结构、分子和生化发生了巨大的变化。本申请的重点是研究脑外伤后突触的超微结构和分子重组及生化修饰，并验证突触损伤的重组和修饰可能导致脑外伤后功能改变和神经元缓慢型丧失的假说。具体目标是：1)。目的：应用定量电子显微镜（EM）和电子断层扫描（EM）研究脑外伤后突触的超微结构改变。2)。首先通过纯化突触来研究脑外伤后突触的分子重组，然后使用纯化的突触进行蛋白质组学和微测序。3）. 研究脑外伤后谷氨酸受体的表达、转换及其与蛋白激酶的相互作用。4)。研究脑外伤后LTP和LTD的变化，并探讨LTP和LTD的变化与脑外伤后可能的形态学、分子和生化突触变化之间的关系。突触连接是一个非常动态和可塑性的过程，它通过突触的形态、分子和翻译后生化修饰来调节，但严重的损伤可能导致突触损伤。这种改变和损伤可能代表了损伤后突触可塑性和损伤的基本过程。了解这些变化和损害是开发治疗干预措施的关键。在这个应用中，我们提出了旨在研究脑外伤后突触的改变和损伤的研究。

The objective of this project is to investigate synaptic modification and damage after traumatic brain injury (TBI) and to propose its possible role in the behavioral and cognitive changes, and neuronal death seen in this condition. We, as well as many others, have found that LTP is impaired, and behavioral deficits developed after TBI in rats. In spite of the large body of evidence obtained from neurophysiological and behavioral studies linking changes of neurotransmission to the sequelae of TBI, few studies deal with the possible morphological, molecular and biochemical modifications of synapses per se underlying the functional changes and neuronal loss. This may be, in part, because conventional electron microscopic methods cannot easily detect morphological modification of synapses after injury, while biochemical and molecular biological methods for such studies are often complicated by the contamination of other subcellular components in the analyzed samples. We have recently established a series of techniques to study changes after brain insults, and found dramatic ultrastructural, molecular and biochemical changes of synapses after brain ischemia. The focus of the present application is to study ultrastructural and molecular reorganization and biochemical modification of synapses after TBI, and to test the hypothesis that the reorganization and modification of damage of synapses may contribute to the functional changes and the slow type of neuronal loss seen after TBI. The Specific Aims are: 1). To study ultrastructural modification of synapses after TBI by quantitative electron microscopy (EM) and EM tomography. 2). To investigate molecular reorganization of synapses after TBI first by purification of synapses, then performing proteomics in conjunction with microsequencing using purified synapses. 3). Study glutamate receptor expression, turnover and interaction with protein kinases after TBI. 4). To study LTP and LTD after TBI and to correlate the LTP and LTD changes with the possible morphological, molecular and biochemical synaptic changes after TBI. Synaptic junction is a very dynamic and plastic process that is regulated via morphological, molecular and post-translational biochemical modification of synapses However, severe insults may cause damage of synapses. Such modification and damage may represent fundamental processes in synaptic plasticity and damage after injury. Knowing these modifications and damage are keys to developing therapeutic interventions. In this application, we propose studies designed to investigate the modification and damage of synapses after TBI.