PAR-1 Signaling and HAND

描述（由申请人提供）：蛋白酶激活受体-1（PAR-1）是一种G蛋白偶联受体（GPCR），在神经元和小胶质细胞上高度表达。PAR-1激活剂的水平，包括纤溶酶和基质金属蛋白酶（MMP），在HIV相关的神经系统疾病（HAND）中显著增加，一项研究表明PAR-1的水平也增加。虽然尚未在HAND的背景下进行研究，但PAR-1拮抗剂可以防止帕金森病和脑缺血动物模型中的小胶质细胞活化和神经毒性。 最近的研究表明，选择GPCR可以与？抑制蛋白激活糖原合成酶激酶-3？？（GSK-3？）通过一种新的非经典信号通路。GSK- 3？抑制剂已经显示出减少响应于HAND相关刺激的神经元损伤。此外，增加GSK-3？活性与HAND相关的病理学有关，包括小胶质细胞活化、神经毒性和突触传递的长期抑制。 在本发明的双重PIR 01提议中，我们假设PAR-1的过度活化刺激非经典GPCR依赖性信号传导途径以可测量地促进HAND相关的小胶质细胞活化和神经元损伤。我们的计划是通过体外研究（目的1和2）测试潜在的机制，以及该途径对小鼠模型中观察到的表型变化的相对体内重要性（目的3）。 支持我们假设的初步数据将包括GSK-3？？在过表达有效PAR-1激动剂的小鼠中的活化和认知障碍。初步数据还将显示在从这些动物分离的CNS衍生细胞中PAR-1依赖性、非经典信号传导的证据。创新来自于对与HAND相关的相对未开发的受体的研究，对该受体的新型信号通路的研究，以及独特小鼠模型的使用。创新还来自于包括通过多电极阵列记录神经元活动和小动物磁共振光谱的技术。我们建议的总体目标是确定辅助治疗的靶点。如果PAR-1激活可以通过增加GSK-3？？活性，正在开发的更特异性抑制这种激酶活性的新药可以被考虑用于治疗这种病症。此外，新开发的口服PAR-1拮抗剂，目前在冠状动脉疾病的临床试验可能会被认为是治疗相同的。

DESCRIPTION (provided by applicant): Protease activated receptor-1 (PAR-1) is a G protein coupled receptor (GPCR) that is highly expressed on neurons and microglia. Levels of PAR-1 activators, including plasmin and matrix metalloproteinases (MMPs), are substantially increased in HIV associated neurological disorders (HAND) and one study has shown that levels of PAR-1 are increased as well. Though not yet studied in the context of HAND, PAR-1 antagonists can prevent microglial activation and neurotoxicity in animal models of Parkinson's disease and cerebral ischemia. Recent studies have shown that select GPCRs can associate with ?-arrestins to activate the kinase glycogen synthase kinase-3??(GSK-3?) through a novel, non-canonical signaling pathway. Importantly, GSK- 3?? inhibitors have been shown to reduce neuronal injury in response to HAND relevant stimuli. In addition, increased GSK-3?? activity has been implicated in HAND relevant pathology including microglial activation, neurotoxicity, and long term depression of synaptic transmission. In the present dual PI R01 proposal, we hypothesize that excess activation of PAR-1 stimulates non- canonical GPCR dependent signaling pathways to measurably contribute to HAND relevant microglial activation and neuronal injury. Our plan will be to test underlying mechanisms with in vitro studies (Aims 1 and 2) and the relative in vivo importance of this pathway to phenotypic changes observed in mouse models (Aim 3). Preliminary data in support of our hypothesis will include evidence for GSK-3?? activation and cognitive impairment in mice that overexpress a potent PAR-1 agonist. Preliminary data will also show evidence for PAR-1 dependent, non-canonical signaling, in CNS derived cells isolated from these animals. Innovation comes from the study of a relatively unexplored receptor as related to HAND, the study of a novel signaling pathway for this receptor, and the use of a unique mouse model. Innovation also comes from techniques that include recordings of neuronal activity via multielectrode arrays, and small animal magnetic resonance spectroscopy. The overall goal of our proposal is to identify targets for adjunct therapeutics. If PAR-1 activation can stimulate HAND relevant pathology through increased GSK-3?? activity, novel drugs being developed to more specifically inhibit the activity of this kinase could be considered for treatment of this condition. Moreover, newly developed orally available PAR-1 antagonists that are now in clinical trials for coronary artery disease might be considered for treatment of the same.