BCL-2 FAMILY GENES AND TBI

Bcl-2家族基因在控制神经元细胞程序性死亡中起关键作用。我们已经发现证据表明bcl-2家族基因失调，PCD发生在动物模型和人类TBI中。本研究假设脑外伤后bcl-2家族基因表达改变，导致程序性细胞死亡、氧化应激、神经元死亡和不良行为结果。具体目标如下：1。描述小鼠CCI后bcl-2家族基因（包括bcl-2， bcl-x, Bax）表达的变化。2. 利用过表达bcl-2的转基因小鼠，检测bcl-2表达是否抑制PCD、氧化应激并改善CCI后的组织学和行为学结果。3. 使用受CCI的Bax基因破坏的转基因小鼠，检测Bax表达是否在CCI后触发PCD的必要条件，以及Bax表达是否介导氧化应激、不良的组织学和行为学结果。4. 验证复制缺陷单纯疱疹病毒载体过表达bcl-x-1是否能保护海马神经元免受CCI。5. 通过检测减压开颅术和脑室造口术中切除的人体组织中bcl-2和Bax的表达，确定bcl-2家族表达的类似改变是否发生在人类TBI中。此外，确定脑脊液（核小体）中是否有凋亡的证据。将这些发现与格拉斯哥预后评分（GOS）和其他措施确定的长期结果相关联。提出的实验解决了创伤性脑损伤中bcl-2家族基因改变的关键问题：bcl-2家族基因是否调节创伤后的细胞死亡，或者它们的表达改变是已经注定存活或死亡的细胞的一种附带现象，这些变化是否与人类头部创伤有关？如果这些实验支持bcl-2家族基因调控创伤后细胞死亡的假设，那么改变这些基因的表达或模拟或抑制它们的作用可能为创伤性脑损伤的治疗提供新的策略。

Bcl-2 family genes have a key role in controlling programmed cell death in neurons. We have found evidence that bcl-2 family genes are dysregulated and PCD occurs in both animal models and TBI in humans. The hypothesis of this proposal is that altered expression of bcl-2 family gene occurs after brain trauma and contributes to programmed cell death, oxidative stress, neuronal death, and adverse behavioral outcome. Specific aims are as follows: 1. Characterize alterations in expression of the bcl-2 family genes (including bcl-2, bcl-x, Bax) that occur after CCI in mice. 2. Test whether bcl-2 expression inhibits PCD, oxidative stress and improves histological and behavioral outcome after CCI by use of a transgenic mouse that over-expresses bcl-2. 3. Test whether Bax expression is necessary to trigger PCD after CCI, and whether Bax expression mediates oxidative stress, adverse histological and behavioral outcome by use of Bax-disrupted transgenic mice subjected to CCI. 4. Test whether over-expression of bcl-x-1 by replication deficient herpes simplex viral vectors can protect hippocampal neurons against CCI. 5. Determine if similar alterations in bcl-2 family expression occur in human TBI by examining expression of bcl-2 and Bax in human tissue removed during decompressive craniotomies and CSF from ventriculostomies. Furthermore, determine if there is evidence of apoptosis in CSF (nucleosomes). Correlate these findings with long term outcome as determined by the Glasgow outcome score (GOS) and other measures. The proposed experiments address the key issues regarding the alteration of bcl-2 family genes in traumatic brain injury: Do bcl-2 family genes regulate cell death after trauma or is their altered expression an epiphenomena in cells already destined to live or die, and are these changes relevant to human head trauma? If these experiments support the hypothesis that bcl-2 family genes regulate cell death after trauma, alteration of expression of these genes or mimicking or inhibiting their effects could provide new strategies for treatment of traumatic brain injury.