Studies of the Therapeutic Role of IU1 in a Mouse Model of Ischemic Stroke

描述(申请人提供)：在美国，中风是导致高死亡率和长期残疾的主要原因。中风与错误折叠/聚集蛋白的过度产生有关。然而，蛋白清除异常在缺血性卒中预后中的作用仍远未被了解。泛素蛋白酶体系统(UPS)在去除异常蛋白质中起着至关重要的作用。UPS受多种因素的调节，但最近的数据表明，蛋白酶体相关的脱泛素化酶(DUBS)在调节蛋白酶体活性方面起着重要作用。USP14是与蛋白酶体可逆相关并调节蛋白酶体活性的DUB。最近，一种USP14特异的小分子抑制物IU1被发现(Lee等人。2010，自然467：179-184)。在细胞培养中，IU1加速氧化蛋白的清除，对氧化应激诱导的细胞死亡具有抵抗作用。这些结果提示IU1可能是治疗脑缺血/再灌注性疾病的潜在药物。然而，这还没有在缺血性中风动物模型中进行测试。在这个项目中，我们假设在小鼠身上外周应用IU1将减轻短暂性脑缺血中风后神经元的死亡，促进结构修复和功能恢复。为了验证这一假设，我们将追求以下具体目标。1.在蛋白酶体功能报告小鼠模型中，检测DuB抑制剂IU1是否促进蛋白酶体底物的降解，无论是否有缺血/再灌注。2.确定外周应用IU1是否对局灶性脑缺血所致神经元损伤有保护作用。

DESCRIPTION (provided by applicant): Stroke is a leading cause of high mortality and long-term disability in the United States. Stroke is associated with the over-production of misfolded/aggregating proteins. However, the role of aberrant protein clearance on the outcome of ischemic stroke remains far from being understood. The ubiquitin proteasome system (UPS) plays a critical role in the removal of abnormal proteins. The UPS is regulated by a number of factors but recent data indicate that the proteasome-associated deubiquitinating enzymes (DUBs) play an important role in regulating proteasome activity. USP14 is the DUB that is reversibly associated with the proteasome and modulates proteasome activity. Recently, a USP14-specific small molecule inhibitor, IU1, was identified (Lee et al. 2010, Nature 467:179-184). In cell culture, IU1 accelerates the clearance of oxidized proteins and imparts a resistance effect on oxidative stress-induced cell death. These results suggest that IU1 may be a potential drug that can be used for treating cerebral ischemia/reperfusion-caused disorders. However, this has not been tested in ischemic stroke animal models. In this project, we hypothesize that peripheral administration of IU1 in mice will attenuate neuronal death and promote structural repair and functional recovery following transient cerebral ischemic stroke. To test this hypothesis, the following specific aims will be pursued. 1. Examine whether IU1, a DUB inhibitor, enhances the degradation of a surrogate proteasome substrate in a proteasome function reporter mouse model with or without ischemia/reperfusion. 2. Determine whether peripheral administration of IU1 protects neurons from transient focal cerebral ischemia-caused neuronal injury.