ConProject-001

该项目广泛而长期的目标是开发治疗脊髓小脑性共济失调的新型治疗药物。 (SCAS)。目前尚无有效的治疗或治愈SCA的方法，这在很大程度上是由于对 疾病发病机制。在这个项目中，我们将重点研究脊髓小脑型共济失调2(SCA2)。SCA2是一种 常染色体显性遗传性神经退行性疾病由ataxin-2(Atxn2)基因的多聚Q扩增引起 蛋白。小脑浦肯野细胞(PC)是SCA2患者的主要病理部位。此前，我们的 实验室发现了PC中异常的神经元钙信号，这些信号在PC中起着重要作用 SCAS的发病机制。以往的研究也表明共济失调小鼠PC的神经元活动异常 模特们。我们证明了小电导的正变构调节剂(PAM)能激活钙 钾(SK)通道可使SCA2小鼠PC异常放电模式正常化并缓解 行为和神经病理表型。这些结果表明，SK PAM可能是潜在的有用的 作为治疗SCA2和可能治疗其他共济失调的治疗剂。这个项目汇集了 两个实验室在发现这类病原体方面的技能和专业知识互补。为了实现这一目标， 我们将重点抓好以下具体目标： R21阶段目标1.鉴定新的亚型选择性SK PAM候选基因。我们将确定水晶 SK2通道与原型亚型选择性PAM的复合体结构。我们将获得结构性的 将用于对亚型选择性SK PAM进行虚拟高通量筛选的信息。 R21阶段目标2.验证新型SK PAM的功能活性。我们将使用基于荧光的HIGH 产量测定和电生理方法测试SK PAM候选者。 R33期目标3.研究新型SK PAM对SK通道的特异性。我们将评估 与其他K+、Na+和Ca~(2+)通道相比，SK通道候选SK PAM的特异性 电生理记录。 R33期目标4.研究新型SK PAM对SCA2小脑PC活性的影响 老鼠。我们将表演前。活着。在这些研究中记录PC活动的小脑切片电生理记录。 由此产生的亚型选择性SK PAM将为未来的临床前和临床提供关键线索 发展，满足共济失调患者的关键和未得到满足的需求。这些分子还将提供新的 和独特的研究工具，以了解SK通道在健康和疾病中的生物学功能。 因此，拟议的项目将对基础神经科学和翻译神经科学产生重大影响。

The broad, long-term objective of the project is to develop novel therapeutic agents for spinocerebellar ataxias (SCAs). There is no effective treatment or cure for SCAs, in large part due to insufficient understanding of the disease pathogenesis. In this project, we will focus on spinocerebellar ataxia type 2 (SCA2). SCA2 is an autosomal dominant genetic neurodegenerative disorder caused by polyQ expansion in ataxin-2 (Atxn2) protein. Cerebellar Purkinje cells (PCs) are the main locus of pathology in SCA2 patients. Previously, our laboratory discovered abnormal neuronal calcium signaling in PCs, which play an important role in the pathogenesis of SCAs. Previous studies also suggest that neuronal activity of PCs is abnormal in ataxic mouse models. We demonstrated that positive allosteric modulators (PAMs) of small conductance calcium-activated potassium (SK) channels can normalize the abnormal firing pattern of PCs in SCA2 mice and alleviate behavioral and neuropathological phenotypes. These results suggest that SK PAMs can be potentially useful as therapeutic agents for the treatment of SCA2 and possibly for other ataxias. This project brings together the complementary skills and expertise of two laboratories for the discovery of such agents. To achieve this goal, we will focus on the following specific aims: R21 Phase Aim 1. To identify novel subtype-selective SK PAM candidates. We will determine the crystal structure of SK2 channels in complex with the prototype subtype-selective PAMs. We will obtain structural information that will be used to perform v irtual high throughput screening for subtype-selective SK PAMs. R21 Phase Aim 2. To validate functional activity of novel SK PAMs. We will use fluorescence-based high throughput assay and electrophysiological methods to test SK PAM candidates. R33 Phase Aim 3. To investigate the specificity of novel SK PAMs for SK channels. We will evaluate the specificity of the SK PAM candidates for SK channels over other K+, Na+ and Ca2+ channels using electrophysiological recordings. R33 Phase Aim 4. To investigate the effects of novel SK PAMs on the activity of cerebellar PCs in SCA2 mice. We will perform ex. vivo. cerebellar slice electrophysiological recordings of PC activity in these studies. The resulting subtype-selective SK PAMs will provide critical leads for future preclinical and clinical development, fulfilling the critical and unmet needs in ataxia patients. These molecules will also offer novel and unique research tools for understanding the biological function of SK channels in health and disease. Thus, the proposed project will have significant impact in basic and translational neuroscience.