Mechanisms of Neurodegeneration

描述（由申请人提供）：癫痫和相关神经退行性变有许多不同的潜在原因，其中大多数仍然未知。癫痫疾病基因的鉴定为疾病机制提供了有价值的见解。然而，很少有癫痫基因在接近分子水平的理解，足以帮助指导有效治疗的发展，到目前为止，大多数成功仅限于通道蛋白。人类基因组测序的快速扩展已经确定了功能未知的新癫痫基因，需要新的方法来描述其疾病因果关系的机制。人类KCTD7基因就是一个很好的例子，这是一种新发现的癫痫/神经变性基因。KCTD7突变可导致进行性肌阵挛性癫痫（EPM3）、婴儿期发作的神经性神经样脂褐质病（CLN14）以及可能的其他疾病。然而，除了越来越多的关于患者中KCTD7突变的报道外，基本上对KCTD7的分子功能一无所知（PubMed中有8个“KCTD7”）。我们的目标是基于我们在酵母（Saccharomyces cerevisiae）研究中获得的新见解，结合哺乳动物神经元细胞死亡、线粒体功能和自噬模型，揭示KCTD7的潜在机制。我们实验室的酵母基因筛选发现了一个酵母基因的新功能，该基因具有显著的氨基酸序列相似性，与人类蛋白质的24个成员KCTD家族相似。KCTD7在大脑神经元中特异性表达。我们在酵母中的研究表明，人类KCTD7在营养感知和自噬方面具有意想不到的新功能。我们预计该项目的结果将对了解KCTD7的基本分子机制以及神经变性和癫痫患者的机制产生重大影响。在Aim 1中，我们将使用显微镜和生化方法来确定人类KCTD7在细胞系和原代神经元的营养感知和自噬中的作用。在Aim 2中，我们将描述KCTD7激活和功能的机制，在Aim 3中，我们将通过分析一种新的小鼠模型来模拟EPM3/CLN14患者，来测试这些分子机制的相关性。我们还希望为其他神经退行性过程提供有价值的见解，并推进小鼠模型在癫痫研究中的应用。

DESCRIPTION (provided by applicant): There are many different underlying causes of epilepsy and associated neurodegeneration, most of which are still unknown. Identification of epilepsy disease genes has provided valuable insight into disease mechanisms. However, few epilepsy genes are understood at a level that approaches a molecular understanding sufficient to help guide development of effective therapeutics, and thus far most successes are limited to channel proteins. Rapid expansion of human genome sequencing has identified new epilepsy genes of unknown function, and new approaches are needed to delineate their mechanisms of disease causality. A case in point is the human KCTD7 gene, a newly designated epilepsy/neurodegeneration gene. Mutations in KCTD7 cause progressive myoclonic epilepsy (EPM3), infantile onset neuronal ceroid lipofuscinosis (CLN14), and possibly other disorders. However, except for a growing number of reports identifying KCTD7 mutations in patients, essentially nothing is known about the molecular functions of KCTD7 (8 hits for "KCTD7" in PubMed). Our goal is to uncover the underlying mechanisms of KCTD7 based on novel insights gained from our studies in yeast (Saccharomyces cerevisiae), combined with mammalian models of neuronal cell death, mitochondrial function and autophagy. A yeast genetic screen in our lab uncovered new functions for a yeast gene that has significant amino acid sequence similarity to the 24-member KCTD family of poorly characterized human proteins. KCTD7 is expressed specifically in neurons of the brain. Our studies in yeast suggest new unexpected functions for human KCTD7 in nutrient sensing and autophagy. We predict that the results of the proposed project will have a significant impact on the understanding of basic molecular mechanisms of KCTD7 as well as the mechanisms that underlie neurodegeneration and epilepsy in patients. In Aim 1, we will use microscopy and biochemical approaches to establish the role of human KCTD7 in nutrient sensing and autophagy in cell lines and primary neurons. In Aim 2, we will delineate mechanisms of KCTD7 activation and function, and in Aim 3 we will test the relevance of these molecular mechanisms by analyzing a new mouse model genetically engineered to mimic EPM3/CLN14 patients. We also expect to provide valuable insight into other neurodegenerative processes, and to advance the utility of mouse models in epilepsy research.