Persistent Pre- and Post-Synaptic Changes After Moderate Traumatic Brain Injury and Mitigation with MitoQ

TBI被命名为在最近的阿富汗冲突中服役的军事人员中的标志性伤病 2010-2020年间，伊拉克有超过47万例脑瘫确诊病例。此外，超过 82,468名使用退伍军人管理局进行医疗保健的退伍军人被诊断出至少患有一次脑外伤。慢性突触 交替疗法在脑损伤病理生物学中是一个未被重视的领域，仅有几篇已发表的研究。 在文献(1)、(2)、(3)、(4)中，对亚急性期/慢性期的研究更少。我们的预赛 资料显示，面部有持续性突触前区和突触后区的结构和功能 中度创伤性脑损伤后小鼠的脆弱性。这些长期的变化可能会阻碍突触的适应性 这可能会影响脑的机制(突触可塑性)，从而对脑损伤后的脑恢复产生负面影响。我们 有证据表明突触前和突触后的蛋白质和脂质成分特别脆弱 氧化修饰和蛋白降解，然后导致它们的下调。这些突触变化，如果 持续存在，可能会阻碍大脑的突触适应机制(突触可塑性)，因此对 影响脑外伤后脑功能的恢复。假设：(I)脑外伤可导致蛋白质持续下调 突触前终末活动区的复合体，与囊泡减少有关 神经递质释放功能。(Ii)同时，脑损伤还可引起KEY的氧化和蛋白分解损伤 突触后密度(PSD)-PDZ结构域支架蛋白(PSD93，PSD95， 和相关的钙调素调节剂神经颗粒蛋白，可导致不稳定和减少 突触后膜结合型离子型谷氨酸受体(NR2A、NR2B、GluR1、GluR2)、GABA受体-A /B和多巴胺受体(d1、d2)，从而影响突触后的神经传递能力。(Iii) 研究脑损伤诱导的突触前和突触后蛋白变化和功能障碍可以通过使用 从中度控制皮质损伤的小鼠脑区分离出的突触体制剂 冲击性脑损伤(CCI)和反复闭合性脑损伤(RCHI)最适合检测突触前和突触后蛋白 复合体及囊泡神经递质释放功能与突触后谷氨酸和多巴胺 感受器容量。(Iv)口服线粒体靶向BBB-交叉抗氧化剂Mitoquone的新疗法 (MitoQ)有助于减少脑损伤后突触前和突触后的改变，并改善慢性神经行为 由我们的试点研究支持的功能。 在这项建议中，我们首先旨在(1)研究慢性CCI后和rCHI后关键突触前和rCHI后的变化 突触小体/突触神经体准备中的突触后调制蛋白 免疫组织化学(IHC)染色和免疫电子显微镜检查。然后我们(2)检查慢性预激综合征 突触囊泡神经递质释放能力与突触后谷氨酸受体功能完整性 和突触体准备的能力。我们将(3)将突触前和突触后的变化联系起来 海马区、大脑皮质、前额叶皮质和杏仁核的结构和功能 3个月和12个月时涉及这些脑区的神经行为终点的变化。后颅脑损伤。(4)审查 脑外伤后(CCI或rCHI)每日口服MitoQ治疗3个月和12个月的效果。关于减少氧化应激的问题 突触前和突触后结构/功能受损，突触线粒体功能改善 海马区、大脑周围皮质、前额叶皮质和杏仁核 涉及这些大脑区域的神经行为终结点。在匹配美国退伍军人研究和退伍军人方面 护理任务，这项建议与患有慢性脑外伤的美国退伍军人直接相关，他们可能有持续性的前 以及突触后的变化，对他们的恢复和神经康复过程产生负面影响。

TBI was named the signature injury among military personnel served in the recent conflicts in Afghanistan and Iraq with more than 470,000 confirmed cases of TBI from 2010- 2020. In addition, more than 82,468 Veterans who use VA for their health care have been diagnosed with at least one TBI. Chronic synapse alternations represent an underappreciated area of interest in TBI pathobiology, with only a few published studies in the literature (1),(2),(3),(4) and even less examined in in the subacute/chronic phase of TBI. Our preliminary data show that there are in face persistent pre-synaptic and post-synaptic zone structural and functional vulnerability following moderate TBI in mice. These long-term changes could hinder synaptic adaptive mechanisms of the brain (synaptoplasticity) and therefore negatively affect brain recovery following TBI. We have evidence that presynaptic and post-synaptic protein and lipid components are especially vulnerable oxidative modifications and proteolysis, then leading to their down regulation. These synaptic changes, if persisted, could hinder synaptic adaptive mechanisms of the brain (synaptoplasticity) and therefore negatively affect brain recovery following TBI. Hypothesis: (i) TBI can cause sustained down-regulation of protein complexes at the pre-synaptic terminal active zone, which are associated with diminished vesicular neurotransmitter release function. (ii) In parallel, TBI also can cause oxidative and proteolytic damage of key protein components of the post-synaptic density (PSD) - PDZ-domain scaffold proteins (PSD93, PSD95, gephyrin) and associated calmodulin-regulator neurogranin, which can lead to instability & reduction of postsynaptic membrane-bound ionotropic glutamate receptor (NR2A, NR2B GluR1, GluR2), GABA receptor-A /B and dopamine receptors (D1, D2) and thus compromising the post-synaptic neurotransmission capacity. (iii) Studying TBI–induced pre- and post-synaptic protein alternations and dysfunctions can be facilitated by the use of synaptosome preparations isolated from injured mouse brain regions following moderate controlled cortical impact (CCI) and repeated close head injury (rCHI) are ideally suited to examine pre- and postsynaptic protein complex as well as in vesicular neurotransmitter release function and post-synaptic glutamate and dopamine receptor capacity. (iv) novel therapy with an oral mitochondria-targeting BBB-crossing antioxidant Mitoquinone (MitoQ) can help reduce post-TBI presynaptic and postsynaptic alterations and improve chronic neurobehavioral functions as supported by our pilot studies. In this proposal, we first aim to (1) study chronic post- CCI and post-rCHI alterations of key pre-synaptic and post-synaptic modulatory proteins in synaptosome/synaptoneurosome preparations and by immunohistochemical (IHC) staining and Immuno-electron microscopy. We then (2) examine chronic pre- synaptic vesicular neurotransmitter release capacity and post-synaptic glutamate receptors functional integrity and capacity in synaptosome preparations. We will (3) correlate changes of pre-synaptic and post-synaptic structures and functions in hippocampus, perirhinal cortex, prefrontal cortex and amygdala with corresponding changes in neurobehavioral endpoints involving these brain regions at 3 and 12 mo. post- TBI. (4) Examine the effects of post-TBI (CCI or rCHI) oral daily MitoQ treatment for 3 and 12 mo. on reducing oxidative stress induced damage to pre-synaptic and post-synaptic structures /functions, and improved synaptic mitochondrial function in hippocampus, perirhinal cortex, prefrontal cortex and amygdala with corresponding improvement in neurobehavioral endpoints involving these brain regions. In terms of matching US VA research and Veteran care missions, this proposal is directly relevant to US Veterans with chronic TBI who might have persistent pre- and post-synaptic changes that negatively affect their recovery and neurorehabilitation process.