BCL-2 FAMILY GENES AND TBI

BCL-2家族基因在控制神经细胞程序性死亡中起着关键作用。我们发现有证据表明bcl2家族基因调控失调，PCD在动物模型和人类脑损伤中都会发生。这一假设认为，bcl2家族基因的表达改变发生在脑创伤后，并导致程序性细胞死亡、氧化应激、神经元死亡和不良行为结局。具体目的如下：1.研究小鼠CCI后bcl2家族基因(包括bcl2、bclx、bax)的表达变化。2.利用过表达bcl2的转基因小鼠，检测bcl2的表达是否能抑制CCI后的PCD、氧化应激，并改善组织学和行为学结果。3.利用Bax基因敲除的转基因小鼠进行CCI，检测Bax基因表达是否在CCI后触发PCD所必需，以及Bax基因表达是否介导氧化应激、不良组织学和行为结局。4.检测复制缺陷型单纯疱疹病毒载体过表达bcl-x-1对CCI后海马神经元的保护作用。5.通过检测开颅减压术中取出的人体组织和脑室造瘘术后脑脊液中bcl2和bax的表达，确定bcl2家族的表达在人脑损伤中是否也发生了类似的变化。此外，确定脑脊液(核小体)中是否有细胞凋亡的证据。将这些发现与格拉斯哥结果评分(GOS)和其他指标确定的长期结果相关联。拟议的实验解决了与创伤性脑损伤中bcl2家族基因变化有关的关键问题：bcl2家族基因是否调控创伤后的细胞死亡，或者它们的变化表达是注定要生存或死亡的细胞中的一种偶然现象，这些变化与人类头部创伤有关吗？如果这些实验支持bcl2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仿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.