Kinase Inhibitors against Neurodegeneration

描述(申请人提供)：Niemann-Pick C型(NPC)是一种罕见和致命的神经内脏储存障碍，目前无法治疗，在大多数情况下(95%)，NPC是由NPC1基因突变引起的，NPC1基因编码一种在胆固醇运输中发挥重要作用的糖蛋白。鼻咽癌的特点还包括轴突异常、神经原纤维缠结(NFT)和进行性神经变性。虽然鼻咽癌突变细胞中胆固醇代谢的改变导致轴突和神经元的退化，以及作为NFTs的主要成分的tau蛋白的过度磷酸化，但导致鼻咽癌的病理机制尚不清楚。有趣的是，在鼻咽癌和阿尔茨海默病(AD)中观察到的NFT在化学和形态上是无法区分的，在AD中，它们与痴呆症的严重程度相关。在NPC1-/-小鼠的大脑中，几种蛋白激酶的活性发生了变化，这些变化可能导致tau修饰和神经元死亡。尤其是在NPC1缺陷细胞中，细胞周期蛋白依赖性激酶5(CDK5)和丝裂原活化蛋白激酶(MAPK)的活性升高。这表明蛋白激酶活性的增加在鼻咽癌的发病中起着关键作用。建议的实验针对以下问题：(1)CDK5、GSK3-β和MAP激酶对tau过度磷酸化和NFT形成有什么贡献？(2)这些激酶在NPC1-/-小鼠的病理发展中有什么贡献？因此，我们的具体目标是：(I)利用ApoE-/-小鼠的海马片培养，确定各种蛋白激酶抑制剂对已建立的tau过度磷酸化和NFT形成的体外模型的影响；(Ii)在使用NPC1-/-小鼠的海马片和小脑片培养的类似模型上，测试Aim 1中获得的每类蛋白激酶最有效的抑制剂的作用；以及(Iii)测试所选蛋白激酶抑制剂将在体内防止NPC1-/-小鼠的tau过度磷酸化、神经元变性、小胶质和星形胶质反应以及运动缺陷的假设。所提出的研究有可能(I)确定tau过度磷酸化和缠结形成的途径，(Ii)提供关于特定的蛋白激酶在鼻咽癌疾病的其他病理表现中的作用的关键信息，以及(Iii)为针对NPC和AD的基本方面的广泛的药物发现计划铺平道路。

DESCRIPTION (provided by applicant): Niemann-Pick type C (NPC) is a rare and fatal neurovisceral storage disorder that is currently untreatable, in most cases (95%), NPC is caused by mutations of the NPC1 gene, which encodes a glycoprotein playing an important role in cholesterol transport. NPC brains are also characterized by axonal abnormalities, neurofibrillary tangles (NFTs), and progressive neurodegeneration. The mechanisms leading to pathology in NPC are not well understood, although altered cholesterol metabolism in NPC mutant cells leads to axonal and neuronal degeneration as well as to hyperphosphorylation of the tau protein, which is the major component of NFTs. Interestingly, the NFTs observed in NPC and in Alzheimer's disease (AD) are chemically and morphologically indistinguishable and, in AD, they correlate with the severity of dementia. In brains from NPC1-/- mice, the activity of several protein kinases is altered and these alterations may result in tau modifications and neuronal death. In particular, the activities of cyclin-dependent kinase 5 (cdk5) and mitogen-activated protein kinase (MAPK) are elevated in NPCl-defective cells. This suggests that increased activity of selected protein kinases plays a critical role in NPC pathogenesis. The proposed experiments are directed at the following questions: (1) What are the contributions of cdk5, GSK3-beta, and MAP kinases to tau hyperphosphorylation and NFT formation? (2) What are the contributions of these kinases in the development of pathology taking place in NPC1-/- mice? Therefore, our specific aims are to (i) determine the effects of a variety of protein kinase inhibitors on a well established in vitro model of tau hyperphosphorylation and NFT formation using cultured hippocampal slices from ApoE-/- mice, (ii) test the effects of the most potent inhibitors of each class of protein kinases obtained in Aim 1 on a similar model that uses cultured hippocampal and cerebellar slices from NPC1-/- mice, and (iii) test the hypothesis that selected protein kinase inhibitors will prevent tau hyperphosphorylation, neuronal degeneration, microglial and astroglial reaction, and motor deficits in NPC1-/- mice in vivo. The proposed studies have the potential to (i) identify the pathway responsible for tau hyperphosphorylation and tangle formation, (ii) provide critical information concerning the role of specific protein kinases in other pathological manifestations of NPC disease, and (iii) open the way to broad-based drug discovery programs directed at essential aspects of NPC and AD.