Role of Cyclopentenone prostaglandins in promoting recovery after TBI

描述(由申请人提供)： 创伤性脑损伤(TBI)是退伍军人中的一个主要问题，目前还没有被证明能提高长期康复的有效治疗方法。在新的初步数据中，我们发现大鼠脑损伤后脑内环戊酮前列腺素D12-前列腺素J2(D12-PGJ2)浓度升高。CyPGs如D12-PGJ2是PPARg核受体的有效配体，在创伤和感染后的炎症消退和创面愈合中发挥重要作用。CyPG还可以通过非PPAR3介导的作用损伤神经元，包括破坏泛素蛋白酶体途径(UPP)。在更多的初步数据中，我们发现CyPG结合并抑制神经元中关键的UPP酶-泛素羧基末端水解酶-L1(UCH-L1)的作用，导致泛素化蛋白的积累和神经细胞死亡。在这些拟议的研究中，我们将进一步表征颅脑损伤后CyPG的产生和代谢。我们还将确定PPARg激活和UCH-L1活性恢复在决定脑创伤后恢复和长期行为结果中的作用。具体目标如下：1.研究大鼠控制性皮质损伤(CCI)后环戊酮前列腺素及其代谢物产生的时程特征。2.检测激活PPAR3受体是否能减少脑外伤后的继发性损伤，促进行为恢复。3.检测TAT-UCH-L1融合蛋白系统治疗恢复UCH-L1活性是否能防止Ub蛋白蓄积，改善脑损伤后的行为结局。采用大鼠和小鼠皮质撞击致伤模型，建立大鼠脑损伤模型。用四极LC-MS/MS对CyPG母体的子离子片段进行选择性反应监测，用四极LC-MS/MS测定脑损伤后脑内CyPG的浓度。中性粒细胞的迁移将通过测量脑组织中的肌过氧化物酶活性来量化。已知受PPARg调控的蛋白iNOS、TNFa和MMP-9将通过ELISA法测定，并用作PPARg激活的下游监测。通过免疫印迹和免疫组织化学检测UCH-L1活性和检测泛素化蛋白的积聚，可以确定脑损伤后UPP的破坏情况。行为结果将使用Morris水迷宫程序的工作记忆变化来评估，评估时间为创伤后第14天至第20天。这些初步数据是第一个关于脑外伤后脑内存在CyPG的报告。激活PPARg和恢复失去的UCH-L1活性是治疗脑损伤的新方法，可能导致新的治疗方法，可以促进脑损伤后的长期恢复和功能恢复。

DESCRIPTION (provided by applicant): Traumatic brain injury (TBI) is a major problem in the veteran population and there are no effective treatments proven to improve long-term recovery. In new preliminary data, we have found that the concentration of the cyclopentenone prostaglandin (CyPG) D12-prostaglandin J2 (D12-PGJ2) is increased in rat brain after TBI. CyPGs such as D12-PGJ2 are potent ligands of the PPARg nuclear receptor, and have been proposed to play an important role in resolution of inflammation and wound healing after injury and infection. CyPGs may also injure neurons by non-PPAR3-mediated effects including disruption of the ubiquitin proteasome pathway (UPP). In additional preliminary data, we have found that CyPGs bind to and inhibit the action of the key neuronal UPP enzyme, ubiquitin carboxy-terminal hydrolase-L1 (UCH-L1) in neurons resulting in accumulation of ubiquitinated proteins and neuronal cell death. In these proposed studies, we will further characterize the production of and metabolism of CyPGs after TBI. We will also determine the role of PPARg activation and restoration of UCH-L1 activity in determining recovery after TBI and long term behavioral outcome. The following specific aims are proposed: 1. Characterize the time course of production of cyclopentenone prostaglandins and their metabolites after controlled cortical injury (CCI) in rats. 2. Test whether activation of the PPAR3 receptors reduces secondary injury and improves behavioral recovery after TBI. 3. Test whether restoring UCH-L1 activity by systemic treatment with a TAT-UCH-L1 fusion protein can prevent accumulation of Ub-proteins and improve behavioral outcome after TBI. TBI will be induced using the controlled cortical impact injury model in rats and mice. Concentrations of CyPGs will be measured in brain after TBI by quadrupole LC MS/MS using selective reaction monitoring of daughter ion fragments of the CyPG parent masses. Neutrophil migration will be quantified by measuring myleoperoxidase activity in brain tissue. The proteins, iNOS, TNFa, and MMP-9, which are known to be regulated by PPARg, will be measured by ELISA and used as downstream monitors of PPARg activation. Disruption of the UPP in brain after TBI will be determined by monitoring UCH-L1 activity and detecting accumulation of ubquitinated proteins by immunoblotting and immunohistochemistry. Behavioral outcome will be assessed using a working memory variation of the Morris Water Maze procedure assessed on post trauma days 14 through 20. These preliminary data represent the first report that CyPGs are present in brain after TBI. Activation of PPARg and restoration of lost UCH-L1 activity are new therapeutic approaches to TBI that could lead to novel therapies that could improve long term recovery and restoration of function after TBI.