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。包括纤溶酶和基质金属蛋白酶（MMPs）在内的PAR-1激活因子水平在HIV相关神经系统疾病（HAND）中显著升高，一项研究表明PAR-1水平也升高。虽然尚未在HAND的背景下进行研究，但PAR-1拮抗剂可以在帕金森病和脑缺血动物模型中阻止小胶质细胞激活和神经毒性。最近的研究表明，选择的gpcr可以与？通过一种新的非典型信号通路激活激酶糖原合成酶激酶3 （GSK-3）。重要的是，GSK- 3?？抑制剂已被证明可以减少神经元对HAND相关刺激的损伤。此外，GSK-3?？活性涉及HAND相关病理，包括小胶质细胞激活、神经毒性和突触传递的长期抑制。在目前的双PI R01提案中，我们假设PAR-1的过度激活刺激非典型GPCR依赖的信号通路，从而可测量地促进HAND相关的小胶质细胞激活和神经元损伤。我们的计划是通过体外研究（目标1和2）来测试潜在的机制，以及在小鼠模型中观察到的这种途径对表型变化的相对体内重要性（目标3）。支持我们假设的初步数据将包括GSK-3?？过度表达强效PAR-1激动剂的小鼠的激活和认知障碍。初步数据还将显示从这些动物分离的中枢神经系统来源细胞中存在PAR-1依赖性非规范信号的证据。创新来自于对一种相对未被开发的与HAND相关的受体的研究，对这种受体的新信号通路的研究，以及对一种独特小鼠模型的使用。创新还来自于通过多电极阵列记录神经元活动的技术，以及小动物磁共振波谱。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刺激HAND相关病理？？活性，正在开发的新药，以更具体地抑制这种激酶的活性，可以考虑治疗这种情况。此外，新开发的口服PAR-1拮抗剂目前正在冠状动脉疾病的临床试验中，可能被考虑用于治疗相同的疾病。

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.