Targeting mitostasis via activation of mitochondrial biogenesis after TBI

现代军事行动的经验表明，创伤性脑损伤(TBI)是其标志性损伤。 现代战争使我们的部队成为脑外伤的高危人群。在327,388名OEF/OIF退伍军人中使用 退伍军人管理局在2009年，6.7%的人被诊断为脑外伤，其中73%的人被诊断为创伤后损伤 应激障碍(PTSD)。然而，到目前为止，还没有批准的治疗方法，部分原因是不完全的 了解脑外伤的病理生物学基础。令人信服的实验数据表明线粒体 功能障碍是脑损伤神经病理后遗症的关键环节。这个前提来自于我们的 已发表的工作(以及其他人的工作)表明，线粒体动态平衡的丧失和增加 脑创伤后线粒体活性氧(ROS)产生。保护或恢复 治疗靶向线粒体损伤改善神经功能的实验研究 TBI。在这里，我们提出了一种新的激活线粒体生物发生(MB)的方法，这是 脑外伤后应用药物干预后的线粒体动力学。通过MB，功能失调的线粒体 通过涉及过氧化物酶体增殖物激活受体γ辅活化子1的信号网络被取代- 阿尔法(pgc-1α)作为主调节器。MB的激活可能是一种重要的干预 线粒体动力学和预防脑外伤后代谢紊乱。最近，福莫特罗和福莫特罗两种药物 Lasmiditan已经由我们和我们的合作者进行了筛选，并发现通过激活两个 独立受体分别为β2肾上腺素受体(β2AR)和5羟色胺1F(5 HT1F)。我们 假设在最佳药物剂量下激活MB将改善线粒体功能， 减轻颅脑损伤后的病理改变，恢复认知功能。为了检验这一假设，在特定的目标 1，我们将研究脑损伤后大脑皮质和海马区MB的时间和空间变化。 MB的分子标记分析。我们还将完善和建立剂量反应和治疗 福莫特罗和雷米坦联合治疗优化脑损伤后MB的干预窗。在这一目标中，我们还将 在最佳状态下测试MB激动剂治疗促进脑外伤后认知恢复的假设 治疗方法。在特定目标2中，我们将评估细胞和组织在能量稳态方面的特定变化。 应用生物能量和代谢组学方法进行脑损伤和MB激活治疗后的一种新方法 分离突触线粒体的方法。我们还将研究脑损伤的潜在代谢机制。 利用体内和体外13C标记示踪法和先进的稳定同位素分辨示踪法激活MB 代谢组学分析。最后，在特定目标3中，我们将评估MB激活剂在诱导 在TBI之后的MB。使用5-HT1F/β2AR KO小鼠，我们假设功能益处依赖于 特异性受体信号导致MB的激活。总体而言，我们假设优化治疗方案 这些MB激活剂在脑损伤后的窗口期和剂量反应将导致生物能量稳态的改善 以及脑外伤后的神经认知功能。

Experience in contemporary military operations suggests that traumatic brain injury (TBI) is the signature injury of modern wars 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. Compelling experimental data demonstrate that mitochondrial dysfunction is a pivotal link in the neuropathological sequelae of brain injury. This premise comes from our published work (and that of others) demonstrating that loss of mitochondrial homeostasis and increased mitochondrial reactive oxygen species (ROS) production occurs following TBI. Protecting or restoring mitochondrial function by therapeutically targeting mitochondrial impairment improves neuronal function after TBI. Here, we propose a novel approach of activating mitochondrial biogenesis (MB), a necessary process in mitochondrial dynamics, after TBI using pharmacological intervention. Through MB, dysfunctional mitochondria are replaced via signaling networks involving peroxisome proliferator-activated receptor gamma coactivator 1- alpha (PGC-1α) as a master regulator. Activation of MB can be an important intervention to modulate mitochondrial dynamics and prevent metabolic disruption after TBI. Recently, two drugs formoterol and lasmiditan have been screened by us and our collaborators and found to induce PGC-1α via activation of two independent receptors, β2-adrenoreceptor (β2AR) and 5-hydroxytryptamine1F (5-HT1F) respectively. We hypothesize that MB activation at the optimized drug dosage will improve mitochondrial function, mitigate pathology and restore cognitive function following TBI. To test this hypothesis, in Specific Aim 1, we will examine the temporal and spatial aspects of MB after TBI in the injured cortex and hippocampus by analyzing molecular markers of MB. We will also refine and establish the dose-response and therapeutic window of intervention for formoterol and lasmiditan treatment to optimize MB after TBI. In this Aim, we will also test the hypothesis that treatment with MB activators promotes cognitive recovery following TBI at the optimal therapeutic regime. In Specific Aim 2, we will assess cell- and tissue-specific changes in energy homeostasis following TBI and MB activation therapy using bioenergetic and metabolomic approaches and a novel approach to isolate synaptic mitochondria. We will also examine the underlying metabolic mechanisms of TBI and MB activation using in vivo and ex vivo 13C-labeled tracing followed by advanced stable isotope-resolved metabolomic analysis. Lastly, in Specific Aim 3 we will assess the specificity of MB activators on induction of MB after TBI. Using 5-HT1F/β2AR KO mice, we hypothesize that functional benefit is dependent on the specific receptor signaling leading to activation of MB. Overall, we hypothesize that optimizing the therapeutic window and dose response of these MB activators after TBI will lead to improved bioenergetic homeostasis and neurocognitive performance after TBI.