The Effects of Traumatic Brain Injury in Alpha Synuclein and Dopamine Regulation

描述（由申请人提供）：创伤性脑损伤（TBI）在美国的发生率为每年每10万人中有200例，由于各种神经递质系统（包括多巴胺（DA））的破坏，导致长期的功能和认知缺陷。基于我们过去的研究和文献中的发现，TBI可以诱导神经元中DA增加和α-突触核蛋白（AS）聚集。AS聚集可诱导DA合成和再摄取的失调，导致细胞内DA过量，而细胞内DA过量可导致AS聚集。从这些证据中可以清楚地看出，DA和AS调节可能是相互关联的。阐明AS病理和DA功能障碍之间的联系将提高我们对TBI后认知障碍机制的理解，并有助于制定预防和最大限度减少DA神经传递障碍的治疗策略。此外，它可以为我们提供一个深入了解TBI如何可能导致未来的神经退行性疾病，如突触核蛋白病的风险。我们推测，急性DA增加TBI后可能是一个显着的贡献者AS聚集，这种聚集的AS可能进一步有助于DA的失调。具体目标1将检查抑制DA合成或代谢的效果，以防止由于TBI后急性组织DA增加引起的AS聚集。将进行蛋白质印迹和免疫组织化学，以确认AS的聚集。具体目标2将通过比较野生型和AS基因敲除小鼠在调节DA的酶的水平和活性以及DA本身的水平和释放方面的差异来检查AS聚集体对DA调节的影响。将通过蛋白质印迹法测量酶水平，并通过高效液相色谱法测量产物来评估酶活性。高效液相色谱和微透析将被用于在体内确认DA的水平和释放。本项目将研究TBI后发生的神经递质多巴胺的调节丧失如何可能是由于a-突触核蛋白的病理变化的影响。了解这一机制将有助于我们制定治疗策略，以治疗TBI后的功能缺陷和未来可能发展的神经退行性疾病。 注：下文以基本上未经编辑的形式提供了个别审查者的评论。这些评论是在评审会议之前编写的，在会议讨论之后可能没有更新或修订。因此，它们可能无法充分反映小组讨论结束时单个评审员的最终意见或小组的最终多数意见。以上讨论的摘要和总结总结了小组讨论的最终结果。

DESCRIPTION (provided by applicant): Traumatic brain injury (TBI) occurs in the United States at an incidence of 200 per 100,000 people annually, causing long lasting functional and cognitive deficits due to disruptions of various neurotransmitter systems, including dopamine (DA). Based on our past studies and findings in the literature, TBI may induce both DA increase in neurons and aggregation of a-synuclein (AS). AS aggregation can induce dysregulation of DA synthesis and reuptake leading to excess DA intracellularly, and intracellular DA excess can lead to AS aggregation. It is clear from these evidences that DA and AS regulation may be interrelated. Clarifying the link between AS pathology and DA dysfunction will improve our understanding of the mechanism of cognitive deficits following TBI and contribute to development of therapeutic strategies to prevent and minimize DA neurotransmission deficits. Furthermore, it may provide us with an insight into how TBI may lead to future risk of neurodegenerative diseases like synucleinopathies. We hypothesize that the acute DA increase after TBI may be a significant contributor to AS aggregation, and this aggregation of AS may furthermore contribute to dysregulation of DA. To support this hypothesis. Specific Aim 1 will examine the effect of inhibiting DA synthesis or metabolism pharmacologically to prevent AS aggregation due to acute tissue DA increase after TBI. Western blotting and immunohistochemistry will be performed to confirm aggregation of AS. Specific Aim 2 will examine the effect of AS aggregates on DA regulation by comparing the differences between wild type and AS knockout mice in the levels and activities of enzymes regulating DA as well as level and release of DA itself. Enzyme levels will be measured by Western blots and enzyme activities will be assessed by measuring the products by high performance liquid chromatography. High performance liquid chromatography and microdialysis in vivo will be used to confirm the levels and release of DA. This project investigates how the loss of regulation of neurotransmitter dopamine occurring after TBI may be due to the affects of pathological changes in a-synuclein protein. Understanding this mechanism will help us develop therapeutic strategies to treat functional deficits after TBI and possible future development of neurodegenerative diseases. NOTE: The critiques of individual reviewers are provided below in an essentially unedited form. These critiques were prepared prior to the review meeting and may not have been updated or revised subsequent to the discussion at the meeting. Therefore, they may not fully reflect the final opinions of the individual reviewers at the close of group discussion or the final majority opinion of the group. The Resume and Summary of Discussion above summarizes the final outcome of the group discussion.