Role of miR-23a/27 a in secondary injury after TBI

 描述(申请人提供)：创伤性脑损伤(TBI)导致神经细胞丢失和相关的运动和认知障碍。潜在的神经细胞死亡是通过多种相互联系的机制来介导的，其中包括激活多个仅BH3和多个BH结构域的促凋亡蛋白。我们的初步数据显示，这些促凋亡的Bcl2家族蛋白在脑创伤后早期在皮质中上调，可能在神经细胞死亡中发挥重要作用。此外，我们还表明，miR-23a和-27a等特定microRNAs的变化可能是这些病理生理事件的重要调节因素。我们建议使用基因工程小鼠模型和miR模拟物的中央给药来检验我们的中心假设，即与针对单独的BH3途径的更有针对性的干预相比，通过miR-23a/27A模拟物联合调制多个促凋亡的BH3和多个BH结构域分子可以更好地减轻脑损伤后的神经元损伤和改善神经功能障碍的减少。具体的目的将显示：目的1.确定通过抑制特定的促凋亡的bcl2分子而提供的个体和累加的神经保护作用。研究#1.1展示了Puma、Noxa或Bim的结构性缺失对脑创伤后神经元丢失和功能障碍的影响。研究1.2比较Puma-/-/Noxa-/-/Bim-/-Triple KO和Bax-/-Bak-/-Double KO对脑创伤后神经元丢失和功能障碍的相加保护作用。目的2.探讨miR23a/27A快速下调的机制，并确定其在体外神经细胞凋亡中的关键靶点。研究2确定miR23a/27a在不同神经细胞凋亡模型中的转录调控因子和关键靶点目的3.论证miR-23a和-27a的相对神经保护作用及其相加效应和治疗窗口；体内检测其在脑损伤后的调节作用和靶点。研究#3.1研究急性中枢(Icv)注射miR-23a和/或miR-27a模拟物对脑创伤后神经元丢失和功能缺陷的影响研究#3.2研究延迟中枢(Icv)给药miR类似物对脑创伤后神经元丢失和功能缺陷的治疗窗口延长治疗窗口。

 DESCRIPTION (provided by applicant): Traumatic brain injury (TBI) leads to neuronal cell loss and associated motor and cognitive deficits. The underlying neuronal cell death is mediated through multiple interconnected mechanisms, which include activation of multiple BH3-only and multi BH-domain pro-apoptotic proteins. Our preliminary data show that early up-regulation of these pro-apoptotic Bcl2 family proteins occur in the cortex after TBI and may play a significant role in neuronal cell death. Furthermore, we show that changes in specific microRNAs such as miR- 23a and -27a may be an important regulator of these pathophysiologic events. We propose to use genetically engineered mouse models and central administration of miR mimics to test our central hypothesis that combined modulation of multiple pro-apoptotic BH3-only as well as multi BH-domain molecules via miR- 23a/27a mimics results in superior attenuation of neuronal damage and improved reduction in neurological deficits after TBI, compared to more targeted interventions directed toward individual BH3-only pathways. Specific Aims will show that: Aim 1. To determine the individual and additive neuroprotection provided by inhibiting specific pro-apoptotic Bcl2 molecules after TBI. Study #1.1 Demonstrate the effects of constitutive deletion of Puma, Noxa or Bim on neuronal loss and functional deficits after brain trauma. Study #1.2 Compare the additive neuroprotective effects of Puma-/-/Noxa-/-/Bim-/- triple KO with those of Bax-/- Bak-/- double KO on neuronal loss and functional deficits after brain trauma Aim 2. To examine the mechanisms underpinning the rapid down-regulation of miR23a/27a and identify their key targets in neuronal apoptosis in vitro. Study #2 Identify the regulators of transcription and key targets for miR23a/27a in various models of neuronal apoptosis Aim 3. To demonstrate the relative neuroprotective effects of miR-23a and -27a as well as their additive benefits and therapeutic window; examine their modulation and targets after TBI in vivo. Study #3.1 Examine effects of acute central (icv) administration of miR-23a and/or miR-27a mimics on neuronal loss and functional deficits after brain trauma Study #3.2 Examine the therapeutic window of delayed central (icv) administration of miR mimics on neuronal loss and functional deficits after brain trauma after TBI with an extended therapeutic window.