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

描述（由申请人提供）：在美国，创伤性脑损伤（TBI）的发生率为每年10万人中200人，由于包括多巴胺（DA）在内的各种神经递质系统的破坏，导致长期的功能和认知缺陷。根据我们以往的研究和文献发现，创伤性脑损伤可能导致神经元DA增加和a-突触核蛋白（AS）聚集。AS聚集可诱导DA合成和再摄取失调，导致细胞内DA过量，细胞内DA过量可导致AS聚集。从这些证据可以清楚地看出，DA和AS调控可能是相互关联的。阐明AS病理与DA功能障碍之间的联系将提高我们对TBI后认知功能障碍机制的理解，并有助于制定预防和减少DA神经传递障碍的治疗策略。此外，它可能为我们提供了一个深入了解创伤性脑损伤如何导致未来神经退行性疾病如突触核蛋白病的风险。我们假设脑外伤后急性DA增加可能是AS聚集的重要因素，而AS的聚集可能进一步导致DA失调。来支持这个假设。特异性目的1将研究抑制DA合成或代谢的药理学作用，以防止由于TBI后急性组织DA增加而导致的AS聚集。Western blotting和免疫组化检测AS是否聚集。特异性目标2将通过比较野生型和AS敲除小鼠在DA调节酶的水平和活性以及DA本身的水平和释放方面的差异，来研究AS聚集体对DA调节的影响。酶水平将通过免疫印迹法测定，酶活性将通过高效液相色谱法测定产物来评估。用高效液相色谱法和体内微透析法确定DA的水平和释放。本项目探讨脑外伤后神经递质多巴胺调节功能的丧失可能是由于a-突触核蛋白病理改变的影响。了解这一机制将有助于我们制定治疗TBI后功能缺陷的治疗策略，并可能在未来发展为神经退行性疾病。

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.