mitoNEET as a therapeutic target for TBI

不断积累的临床证据以及当代军事行动的经验表明， 创伤性脑损伤(TBI)是这场战争的标志性损伤，使我军成为脑损伤的高危人群。 在2009年使用退伍军人服务的327,388名OEF/OIF退伍军人中，6.7%的人被诊断为脑外伤，其中73%的人被诊断为脑损伤 其中一些人被诊断为创伤后应激障碍(PTSD)。然而，到目前为止，还没有批准 对脑损伤的治疗，部分原因是对脑损伤背后的病理生物学了解不完全。因此 迫切需要在这一研究领域取得进展。最近，我们已经证明了吡格列酮是 脑外伤后的神经保护作用机制可能与其与脑损伤的相互作用直接相关。 线粒体蛋白mitoNEET。与这些想法一致，我们的初步结果表明吡格列酮不是 在mitoNEET基因敲除动物中的保护作用，以及用特定的mitoNEET配体(N11)治疗，是 颅脑损伤后的神经保护作用。拟议的实验旨在通过以下方式阐明这一机制(S) 哪一种吡格列酮通过检验新的假说来提供脑外伤后的神经保护 吡格列酮通过mitoNEET相互作用直接改善线粒体功能障碍。为了测试这一点 假设我们提出了三个具体目标，其中包括使用多种创新工具和技术 我们手头有一种新的mitoNEET配体(NL-1)，特别是使用mitoNEET缺失转基因小鼠和 拮抗剂(NL-3)。在具体目标1中，我们将确定最佳剂量和治疗窗口 损伤后吡格列酮维持线粒体动态平衡的机会。这些测量结果将为 第一次，测量损伤核心和非突触线粒体的线粒体功能障碍 来自单一动物的半影区。在特定目标2中，将测量大脑皮层的备用程度和行为 使用确定的最佳剂量通过脑损伤后吡格列酮治疗而实现的改善 具体目标1。在这个目标中，我们将使用T2加权和DTI MRI来纵向评估大脑皮质的变化 以及损伤后3、3、7、14、28和168天的海马区形态和无偏体视学。 伤后168天。此外，我们还将测量急性运动、系列认知功能测试和攻击性 行为功能和恐惧条件作用(创伤后应激障碍的慢性测量)以评估功能程度 治疗后痊愈。具体目标3将确定吡格列酮的作用机制 通过检验吡格列酮的治疗效应是通过相互作用来调节的假说来进行神经保护 使用mitoneet。这一目标将使用转基因mitoNEET缺失小鼠和一种新的mitoNEET 特异性配体(NL-1)和丝裂素受体拮抗剂(NL-3)。线粒体生物能量学将在24小时内进行测量 行为结局和组织保留情况将在脑外伤后进行测量。这些研究的结果将不会 他们不仅阐明了脑损伤神经病理学中涉及的基本过程，而且还推动了 FDA化合物用于治疗脑损伤的重新用途和拟议的实验可能会确定潜在的 治疗颅脑损伤的新靶点，也许还有其他神经元损伤。

Accumulating clinical evidence, as well as experience in contemporary military operations, suggests that traumatic brain injury (TBI) is the signature injury of this war making our troops a high-risk population for TBI. Among the 327,388 OEF/OIF veterans using VA services in 2009, 6.7% were diagnosed with TBI of which 73% of those were diagnosed with posttraumatic stress disorder (PTSD). However, to date there is no approved treatment for TBI, in part due to an incomplete understanding of the pathobiology underlying TBI. Therefore progress in this area of research is desperately needed. Recently, we have shown that pioglitazone is neuroprotective following TBI and that its mechanism of action may be directly related to its interactions with the mitochondrial protein mitoNEET. Consistent with these ideas, our preliminary results indicate pioglitazone is not protective in mitoNEET knockout animals and that treatment with a specific mitoNEET ligand (NL1), is neuroprotective following TBI. The proposed experiments are designed to elucidate the mechanism(s) by which pioglitazone confers neuroprotection following TBI by testing the novel hypothesis that pioglitazone, via mitoNEET interaction directly ameliorates mitochondrial dysfunction. To test this hypothesis we propose three specific aims that include the use of multiple innovative tools and techniques that we have in hand, specifically the use of mitoNEET null transgenic mice, a novel mitoNEET ligand (NL-1) and antagonist (NL-3). In Specific Aim 1, we will determine the optimal dosage and therapeutic window of opportunity for pioglitazone to maintain mitochondrial homeostasis post-injury. These measurements will, for the first time, measure mitochondrial dysfunction from synaptic and nonsynaptic mitochondria in the injury core and penumbra from a single animal. In Specific Aim 2 will measure the degree of cortical sparing and behavior improvements that are mediated through pioglitazone treatment after TBI using the optimal dosage determined in Specific Aim 1. In this aim we will use T2 weighted and DTI MRI to longitudinally assess changes in cortical and hippocampal morphology at -3, 3, 7, 14, 28, and 168 days post-injury followed by unbiased stereology at 168 days post-injury. Additionally we will measure acute motor, serial cognitive functional testing and aggressive behavioral function and fear conditioning (chronic measurements of PTSD) to assess the degree of functional recovery as a result of treatment. Specific Aim 3 will determine the mechanism by which pioglitazone affords neuroprotection by testing the hypothesis that pioglitazone's therapeutic effect is mediated through interactions with mitoNEET. This aim will employ the use of transgenic mitoNEET null mice in tandem with a novel mitoNEET specific ligand (NL-1) and mitoNEET antagonist (NL-3). Mitochondrial bioenergetics will be measured at 24 hours and behavioral outcome and tissue sparing will be measured following TBI. The results of these studies will not only shed light on the fundamental processes involved in TBI neuropathology they also move forward the repurposing of an FDA compound for the treatment of TBI and the proposed experiments may pinpoint potential novel targets for the treatment of TBI and perhaps, other neuronal injuries.