Differential Brain-Region Specific Roles of CASK in Optic Nerve Hypoplasia and Pontocerebellar Hypoplasia

CASK 在视神经发育不全和脑桥小脑发育不全中的不同脑区特异性作用

• 批准号: 10427180
• 负责人: Paras Patel
• 金额: $ 1.55万
• 依托单位: VIRGINIA POLYTECHNIC INST AND ST UNIV
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-04-13 至 2022-05-09
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10427180
• 关键词: ARHGEF5 gene; Acute; Adult; Affect; Anatomy; Apoptosis; Apoptotic; Ataxia; Atrophic; Brain; Brain region; Caliber; Cell Adhesion Molecules; Cell Count; Cell Death; Cell physiology; Cells; Cellular Stress; Cerebellar degeneration; Cerebellum; Cessation of life; Chronic; Congenital cerebellar hypoplasia; DNA Nucleotidylexotransferase; DNA Sequence Alteration; Data; Deterioration; Development; Dorsal; Electrons; Electrophysiology (science); Enterobacteria phage P1 Cre recombinase; Evoked Potentials; Fibrous Astrocyte; Frequencies; Functional disorder; Gene Mutation; Genes; Genetic; Genetic Diseases; Glial Fibrillary Acidic Protein; Human; Image; Impairment; In Situ Hybridization; In Situ Nick-End Labeling; Individual; Injections; Iron; Knockout Mice; Label; Lateral Geniculate Body; Lead; Link; Lipid Peroxidation; Lipids; Longevity; Maintenance; Measures; Mediating; Microcephaly; Microscopy; Modeling; Molecular; Morphology; Mosaicism; Motor; Mus; Mutation; Nature; Necrosis; Nerve Degeneration; Nervous System Physiology; Neuraxis; Neurology; Optic Nerve; Oxidative Stress; Pathogenicity; Pathologic; Pathology; Pathway interactions; Personal Satisfaction; Phenotype; Photons; Physiological; Physiology; Play; Pontine structure; Pontocerebellar hypoplasia; Productivity; Property; Proteins; Public Health; Purkinje Cells; RIPK3 gene; Reactive Oxygen Species; Retina; Retinal Ganglion Cells; Role; Scaffolding Protein; Slice; Specificity; Stains; Stress; Synapses; System; Tamoxifen; Testing; Thalamic structure; Thinness; Time; Tomatoes; United States; Vision; Visual; Visual Cortex; Visual evoked cortical potential; Visual system structure; X Inactivation; awake; base; brain volume; cell type; functional loss; granule cell; mouse model; nervous system development; nervous system disorder; neurophysiology; oxidation; postnatal; promoter; protein complex; ranpirnase; translational neuroscience

PROJECT SUMMARY Understanding how different regions of the central nervous system (CNS) are affected by genetic insults is critical to advancing the study of CNS pathologies which present a major public health burden in the United States. The cerebellum and optic nerve are two such regions that are disproportionately hypoplastic in the majority of cases of CASK gene mutation in humans. CASK is an enigmatic multi-domain scaffolding protein which plays a vital role in organizing protein complexes at the pre-synapse through interactions with both active zone proteins and trans-synaptic adhesion molecules such as liprins-α and neurexins. Mutations in the X-linked CASK gene in humans are largely post-natally lethal in the hemizygous condition and result in microcephaly with pontine and cerebellar hypoplasia (PCH) as well as optic nerve hypoplasia (ONH) in heterozygous mutations. While CASK has been traditionally regarded as playing a role in CNS development, recent data indicate that it plays a continued role in the maintenance of the adult CNS. Specifically, acute global deletion of Cask in adult mice using a CreER-Tamoxifen system leads to progressive degeneration in motor coordination culminating in profound ataxia several months after tamoxifen injection. This coincides with a progressive deterioration of cerebellar gross morphology. Thus, this presents a unique opportunity to understand the continued role of a gene, previously regarded as developmentally important, in the function of the adult CNS and how this function may differ in a region-specific manner. Recently, it has been demonstrated that progression of ONH in the context of CASK-loss is non-cell autonomous in nature as deleting Cask from retinal ganglion cells themselves does not exacerbate ONH, but deleting it from fibrous astrocytes of the optic nerve does exacerbate ONH. However, when Cask is deleted specifically in granule cells (GCs) using a Calb2 promoter driven Cre recombinase, there appears to be a cell- autonomous death of GCs. This provides an opportunity to examine how underlying etiopathology and functional loss differ in two regions given the same genetic insult. As granule cells are the major excitatory driver of the cerebellum, this project will investigate the progression of granule cell loss, the correlation of granule cell loss to functional motor loss and ataxia, and the electrophysiological implications of loss of the major excitatory driver in an isolated brain region. Further, the project will elucidate whether aberrations in spike-timing and frequency among cerebellar Purkinje cells precede or follow anatomical reductions in granule cell number. The project will also examine whether visual function correlates to optic nerve diameter in models which display ONH but not PCH and vice versa using visual evoked potential recordings from V1 of visual cortex and the dorsal lateral geniculate nucleus of the thalamus. Finally, the study will determine molecular mechanisms of non-apoptotic or apoptotic cell death underlying loss of GCs. Thus, the study will investigate differing causes and functional consequences with region-specificity in the context of a single genetic insult using Cask deletion as a test-case.

项目概要 了解中枢神经系统 (CNS) 的不同区域如何受到遗传损伤的影响至关重要 推进中枢神经系统病理学的研究，中枢神经系统病理学是美国的主要公共卫生负担。这 小脑和视神经是大多数情况下不成比例发育不全的两个区域 人类CASK基因突变的研究。 CASK 是一种神秘的多结构域支架蛋白，在 通过与活性区蛋白和突触前蛋白的相互作用，在组织突触前蛋白复合物中发挥作用 跨突触粘附分子，例如 liprins-α 和神经毒素。 X连锁CASK基因突变 人类在半合子状态下基本上是出生后致命的，并导致脑桥和小头畸形 杂合突变中的小脑发育不全（PCH）和视神经发育不全（ONH）。 虽然 CASK 传统上被认为在中枢神经系统发育中发挥着作用，但最近的数据表明 它在维持成人中枢神经系统方面发挥着持续的作用。具体来说，Cask 的急性全局删除 使用 CreER-他莫昔芬系统的成年小鼠会导致运动协调性进行性退化 注射他莫昔芬几个月后，最终出现严重共济失调。这与渐进的 小脑总体形态恶化。因此，这提供了一个独特的机会来了解 以前被认为对发育很重要的基因在成人中枢神经系统功能中的持续作用 该功能如何因地区特定的方式而有所不同。 最近，已经证明在 CASK 丢失的情况下 ONH 的进展是非细胞的 本质上是自主的，因为从视网膜神经节细胞本身删除 Cask 不会加剧 ONH，但是 从视神经纤维星形胶质细胞中删除它确实会加剧ONH。但是，当 Cask 被删除时 特别是在使用 Calb2 启动子驱动的 Cre 重组酶的颗粒细胞 (GC) 中，似乎存在一种细胞- GC 的自主死亡。这提供了一个机会来检查潜在的病因病理学和功能 受到相同基因损伤的两个区域的损失有所不同。由于颗粒细胞是主要的兴奋驱动因素 小脑，该项目将研究颗粒细胞损失的进展，颗粒细胞损失与小脑的相关性 功能性运动丧失和共济失调，以及主要兴奋性驱动因素丧失的电生理学影响 在一个孤立的大脑区域。此外，该项目将阐明尖峰时间和频率是否存在偏差 小脑浦肯野细胞中颗粒细胞数量的解剖学减少之前或之后。该项目将 还检查显示 ONH 但不显示的模型中视觉功能是否与视神经直径相关 PCH 和反之亦然，使用视觉皮层 V1 和背外侧的视觉诱发电位记录 丘脑膝状核。最后，该研究将确定非凋亡或凋亡的分子机制。 GC 损失导致细胞凋亡。因此，该研究将调查不同的原因和功能 使用 Cask 删除作为测试用例，在单一基因损伤的背景下产生区域特异性的后果。