KPTN Loss and Megalencephaly: mTOR Activation as Therapeutic Target

KPTN 丢失和巨脑畸形：mTOR 激活作为治疗靶点

基本信息

批准号：
10375917
负责人：
Peter B Crino
金额：
$ 37.74万
依托单位：
UNIVERSITY OF MARYLAND BALTIMORE
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-01-01 至 2025-12-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10375917
关键词：
19q13.32 AKT3 gene Abnormal Cell Adult Affect Age Amino Acids Amish Biological Assay Biological Models Birth Brain Brain imaging CRISPR/Cas technology Caring Cell Proliferation Cell Size Cellular Morphology Child Clinic Clinical Clinical Data Clinical Trials Collaborations Communities Complex Data Databases Development Developmental Delay Disorders Diagnostic Electroencephalography Enrollment Epilepsy Excision Exhibits FRAP1 gene Family General Population Genes Genome Genotype Head circumference Histopathology Hospitals Human In Vitro Individual Intellectual functioning disability International Intervention Investigation Knockout Mice Laboratories Life Link Measurement Medical Medicine Megalencephaly Modeling Mouse Strains Mus Muscle hypotonia Mutation Neurologic Neurons Neuropsychological Tests Ohio Operative Surgical Procedures PTEN gene Parents Pathogenicity Pathway interactions Patients Pennsylvania Phenotype Plant Leaves Play Polyhydramnios, megalencephaly, and symptomatic epilepsy Population Refractory Registries Research Role Running Seizures Signal Transduction Sirolimus Specialist Syndrome Thick Variant autism spectrum disorder brain magnetic resonance imaging brain overgrowth brain size cell motility clinical center cohort college hemimegalencephaly in vivo in vivo Model infancy inhibitor loss of function mTOR inhibition mouse model nerve stem cell neuroimaging prevent prospective protein complex response therapeutic target

项目摘要

Mutations in select mTOR pathway genes (MPG) are associated with megalencephaly (ME) and/or hemimegalencephaly (HME) including MTOR (Smith-Kingsmore syndrome, ME), STRADA (Pretzel syndrome, ME), PI3KCA (ME/HME), AKT3 (HME), PTEN (ME), DEPDC5 (HME) and RHEB (HME). Autosomal recessive germline variants in KPTN (kaptin; 19q13.32), part of the mTOR regulatory KICSTOR complex, have been recently identified in a clinical syndrome characterized by ME, intellectual disability, autism, and severe epilepsy (Baple et al., 2014) among the Old Order Amish communities in Ohio and Pennsylvania and more recently outside of the Plain Communities. There are 8 established pathogenic KPTN variants (loss of function) all linked to the clinical syndrome Megalencephaly, Autism, Seizures Developmental Delay (KPTN/MASD). The neurological phenotype includes hypotonia in infancy, autism spectrum disorder, intellectual disability (mild to severe), and seizures (onset between 3 months-27 years). Seizures are typically refractory to standard medical treatments and not amenable to resective surgery). ME is a universal feature of KPTN/MASD by adulthood (orbitofrontal head circumference [OFC] >2 standard deviations for age, with OFC measurements up to 5.4 SDS). Strikingly, serial OFC measurements available from 31 children, revealed that OFC is typically within normal limits at birth, with a rapid increase in OFC within the first 2 years of life with ~75% of patients with OFC >2 SDS by that age. Neuroimaging in a limited number of cases revealed a globally enlarged but structurally normal brain. A Kptn -/- mouse strain was recently developed and now is under investigation in our lab. Amazingly, Kptn-/- mice, but not Kptn +/- mice, also exhibit a ME phenotype with post-natal brain overgrowth, thus mirroring the clinical KPTN/MASD phenotype. This application proposes 3 Aims to investigate the mouse and human KPTN/MASD phenotypes. In Aim 1, we will define the effects of Kptn CRISPR/Cas9 KO in vitro on mTOR pathway activation, cell morphology, and cell motility and effects of mTOR pathway inhibitors (mTORi) in murine neural progenitor cells and neurons. In Aim 2, we will analyze the Kptn -/- brain including histopathology, mTOR signaling activation, and hyperexcitability (EEG), and response to mTORi. In Aim 3 we will define the neurological phenotype of KPTN/MASD in an existing and prospectively collected cohort of individuals within the Plain Community and in the general population. Because of the close phenotypic overlap between the Kptn -/- mouse model and human KPTN/MASD, these studies provide a unique opportunity to set the stage for an interventional clinical trial in KPTN/MASD to prevent brain overgrowth.

特定 mTOR 通路基因 (MPG) 的突变与巨脑畸形 (ME) 和/或半侧巨脑畸形 (HME)，包括 MTOR（史密斯-金斯莫尔综合征，ME）、STRADA（椒盐卷饼综合征， ME)、PI3KCA (ME/HME)、AKT3 (HME)、PTEN (ME)、DEPDC5 (HME) 和 RHEB (HME)。常染色体隐性遗传 KPTN（kaptin；19q13.32）是 mTOR 调节 KICSTOR 复合体的一部分，其种系变异已被最近发现一种临床综合征，其特征是 ME、智力障碍、自闭症和严重的俄亥俄州和宾夕法尼亚州等地旧秩序阿米什社区的癫痫病（Baple 等，2014）最近在平原社区之外。有 8 种已确定的致病性 KPTN 变异（功能丧失）所有这些都与临床综合征巨脑畸形、自闭症、癫痫发作发育迟缓（KPTN/MASD）有关。神经表型包括婴儿期肌张力减退、自闭症谱系障碍、智力障碍（轻度至严重）和癫痫发作（3 个月至 27 岁之间发作）。癫痫发作通常难以达到标准药物治疗且不适合切除手术）。 ME 是 KPTN/MASD 的通用功能成年期（眶额头围 [OFC] > 2 个年龄标准差，OFC 测量值至 5.4 SDS）。引人注目的是，对 31 名儿童进行的一系列 OFC 测量表明，OFC 通常是出生时处于正常范围内，约 75% 的患者在生命的头 2 年内 OFC 迅速增加到那个年龄时 OFC >2 SDS。在有限数量的病例中进行的神经影像检查显示，全球范围内扩大了但大脑结构正常。最近开发了 Kptn -/- 小鼠品系，目前正在我们的研究中进行研究实验室。令人惊讶的是，Kptn-/- 小鼠（而非 Kptn +/- 小鼠）也表现出产后大脑的 ME 表型过度生长，从而反映了临床 KPTN/MASD 表型。该申请提出了 3 个调查目的小鼠和人类 KPTN/MASD 表型。在目标 1 中，我们将定义 Kptn CRISPR/Cas9 的效果体外 KO 对 mTOR 通路激活、细胞形态、细胞运动以及 mTOR 通路的影响小鼠神经祖细胞和神经元中的抑制剂（mTORi）。在目标 2 中，我们将分析 Kptn -/- 大脑包括组织病理学、mTOR 信号激活、过度兴奋 (EEG) 以及对 mTORi 的反应。在目标 3 我们将在现有和前瞻性收集的数据中定义 KPTN/MASD 的神经表型平原社区和一般人群中的个体群体。由于距离较近 Kptn -/- 小鼠模型和人类 KPTN/MASD 之间的表型重叠，这些研究提供了为 KPTN/MASD 预防脑损伤的介入临床试验奠定基础的独特机会过度生长。