APOPTOSIS IN TRAUMATIC SPINAL CORD INJURY

创伤性脊髓损伤中的细胞凋亡

基本信息

批准号：
6089984
负责人：
JOE E SPRINGER
金额：
$ 27.91万
依托单位：
UNIVERSITY OF KENTUCKY
依托单位国家：
美国
项目类别：
财政年份：
2000
资助国家：
美国
起止时间：
2000-02-07 至 2004-01-31
项目状态：
已结题

项目摘要

The studies proposed in this grant application focus on identifying and characterizing the molecular signaling events involved in apoptotic cell death following traumatic spinal cord injury (SCI). Despite the recent evidence of widespread apoptosis in neurons and glia after SCI, the molecular components of the apoptotic pathway remain largely unknown. The proposed experiments will provide evidence of components in the apoptotic machinery responsible for initiating and executing this cell death process. In addition, experiments are proposed to demonstrate that blocking steps involved in the apoptotic cell death pathway provides neuroprotection and promotes functional recovery in acute SCI. We hypothesize that calcineurin-mediated BAD dephosphorylation is one of the initial upstream events in the apoptotic cascade and is linked to caspase-3 activation. Glutamate-induced Ca2+ influx leads to calcineurin activation and high levels of glutamate are released soon after SCI. Therefore, we will examine whether intrathecal injections of selective glutamate receptor agonists into uninjured spinal cord lead to calcineurin- mediated BAD dephosphorylation. In addition, we will demonstrate that injections of glutamate receptor antagonists reduce activation of the caspase-3 apoptotic cascade. Finally, the contribution of apoptosis to the functional deficits observed following SCI is not clear at this time. Therefore, we will treat injured animals with inhibitors targeting calcineurin and caspase-3 and use morphological, histological, and behavioral criteria to measure indices of apoptotic cell death and functional recovery. The outcome of these studies will have clear clinical implications for minimizing secondary neuronal and glial cell death and promoting recovery of function following SCI.

本拨款申请中提出的研究重点是识别和表征创伤性脊髓损伤 (SCI) 后细胞凋亡相关的分子信号事件。尽管最近有证据表明 SCI 后神经元和神经胶质细胞广泛凋亡，但凋亡途径的分子成分仍然很大程度上未知。拟议的实验将提供细胞凋亡机制中负责启动和执行细胞死亡过程的组件的证据。此外，还提出了实验来证明凋亡细胞死亡途径中涉及的阻断步骤可提供神经保护并促进急性 SCI 的功能恢复。我们假设钙调神经磷酸酶介导的 BAD 去磷酸化是细胞凋亡级联中的初始上游事件之一，并且与 caspase-3 激活有关。谷氨酸诱导的 Ca2+ 内流导致神经钙蛋白激活，并且在 SCI 后不久释放出高水平的谷氨酸。因此，我们将检查向未损伤的脊髓鞘内注射选择性谷氨酸受体激动剂是否会导致钙调神经磷酸酶介导的 BAD 去磷酸化。此外，我们将证明注射谷氨酸受体拮抗剂可减少 caspase-3 凋亡级联的激活。最后，细胞凋亡对 SCI 后观察到的功能缺陷的影响目前尚不清楚。因此，我们将用针对钙调神经磷酸酶和 caspase-3 的抑制剂治疗受伤的动物，并使用形态学、组织学和行为标准来测量凋亡细胞死亡和功能恢复的指标。这些研究的结果对于最大限度地减少继发性神经元和神经胶质细胞死亡并促进 SCI 后的功能恢复具有明确的临床意义。