Roles of the X-linked Intellectual Disability gene ZDHHC9 in White Matter formation

X连锁智力障碍基因ZDHHC9在白质形成中的作用

• 批准号: 10354435
• 负责人: Gareth Thomas
• 金额: $ 42.02万
• 依托单位: TEMPLE UNIV OF THE COMMONWEALTH
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-20 至 2024-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10354435
• 关键词: Acyltransferase; Address; Adult; Affect; Axon; Brain Diseases; Cells; Cellular Structures; Cerebral Palsy; Code; Cognitive deficits; Corpus Callosum; Development; Electrons; Enzymes; Epilepsy; Event; Genes; Genetic; Golgi Apparatus; Human; Image; Impairment; Intellectual functioning disability; Knockout Mice; Link; Lipids; Maintenance; Mediating; Methods; Microscopic; Mining; Modeling; Molecular; Morphology; Mutation; Myelin; Myelin Basic Proteins; Myelin Proteins; Myelin Sheath; Nervous System Trauma; Nervous system structure; Neuraxis; Neurodevelopmental Deficit; Neurodevelopmental Disorder; Neurons; Oligodendroglia; Palmitates; Patients; Phenotype; Process; Prosencephalon; Protein Isoforms; Proteins; Reporting; Resources; Role; Seizures; Techniques; Time; Viral; Work; X-linked intellectual disability; base; cell type; dysmyelination; experimental study; in vivo; insight; knock-down; loss of function; loss of function mutation; mutant; myelination; neuron loss; oligodendrocyte lineage; oligodendrocyte precursor; palmitoylation; precursor cell; protein expression; small hairpin RNA; transcriptome sequencing; white matter

Abstract: The myelin sheaths that wrap around axons in the Central Nervous System (CNS) are damaged or formed incorrectly in many developmental brain disorders. We thus sought to better understand the control of myelination and how it may be impaired in such conditions. Essentially all of the major myelin proteins are covalently modified with the lipid palmitate, a process that is often critical for correct protein subcellular localization and function, but how myelin protein palmitoylation is controlled is unknown. We were therefore struck by findings that the X-linked Intellectual Disability (XLID) gene ZDHHC9 codes for a specific palmitoyl acyltransferase enzyme that is highly expressed in oligodendrocytes (OLs), the myelinating cells of the CNS. Importantly, human patients with ZDHHC9 loss-of-function mutations and Zdhhc9 knockout (KO) mice display cognitive deficits and have markedly reduced forebrain white matter volume, suggesting a key role for ZDHHC9 in OL formation and/or function. Our own studies revealed that Zdhhc9 KO mice have impaired corpus callosal myelination without loss of neuronal axons and that Zdhhc9 knockdown cell-autonomously impairs OL maturation after differentiation from Oligodendrocyte Precursor Cells (OPCs) in culture. These striking phenotypes may account for the intellectual disability and/or epileptic seizures seen in human patients with ZDHHC9 mutations. In this project we will more precisely define links between Zdhhc9 mutation and myelination impairments. In Aim 1, we will combine well-established Electron Microscopic (EM) and immunostaining analyses with a genetic fate-mapping strategy to comprehensively define how Zdhhc9 loss impacts OL distribution and axonal myelination in vivo. In Aim 2 we will more precisely determine how cell- autonomous Zdhhc9 loss affects OL differentiation and morphological elaboration. In each Aim we will compare the ability of wild type (wt) and XLID mutant forms of ZDHHC9 to rescue the observed phenotypes. These studies will provide new insights regarding not just the impact of Zdhhc9 loss, but also palmitoylation- dependent control of myelination, a process first reported decades ago but about which almost nothing is known. Insights from this work could thus be invaluable to those studying a range of brain disorders marked by White Matter Impairments.

抽象的： 将中枢神经系统（CNS）围绕轴突包裹的髓鞘被损坏或形成 在许多发育性脑部疾病中错误地错误。因此，我们试图更好地了解 髓鞘形成及其在这种情况下如何受损。本质上，所有主要髓磷脂蛋白都是 用脂质棕榈酸盐共价修饰，该过程通常对于正确的蛋白质亚细胞至关重要 定位和功能，但是如何控制髓磷脂蛋白棕榈酰化是未知的。因此，我们是 被X连锁智障（XLID）基因ZDHHC9编码特定棕榈酰基的发现所击中 在少突胶质细胞（OLS）（CNS的骨髓细胞）中高度表达的酰基转移酶。 重要的是，具有ZDHHC9功能丧失突变和ZDHHC9敲除（KO）小鼠的人类患者显示 认知缺陷，明显减少了前脑白质体积，这表明了关键作用 ZDHHC9在OL形成和/或功能中。我们自己的研究表明，ZDHHC9 KO小鼠受损 Callos Callosal髓鞘化而不会损失神经元轴突，并且ZDHHC9敲除细胞自治 在培养中与少突胶质细胞前体细胞（OPC）分化后，损害OL成熟。这些 引人注目的表型可能解释了人类患者中智障和/或癫痫发作的癫痫发作 带有ZDHHC9突变。在这个项目中，我们将更精确地定义ZDHHC9突变与 髓鞘损伤。在AIM 1中，我们将结合成熟的电子显微镜（EM）和 通过遗传命运策略进行免疫染色分析，以全面定义ZDHHC9损失 在体内影响OL分布和轴突髓鞘。在AIM 2中，我们将更准确地确定细胞 自主ZDHHC9损失会影响OL分化和形态阐述。在每个目标中，我们都会 比较ZDHHC9野生型（WT）和Xlid突变体形式营救观察到的表型的能力。 这些研究将提供有关ZDHHC9损失的影响的新见解，还提供棕榈酰化 - 依赖对髓鞘的控制，这是几十年前首次报道的过程，但几乎没有什么是 已知。因此，这项工作的见解对于研究了一系列脑部疾病的人来说是无价的 白质障碍。