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

• 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
• 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

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.

选择的mTOR通路基因（MPG）中的突变与巨脑畸形（ME）和/或 偏侧巨脑畸形（HME）包括MTOR（Smith-Kingsmore综合征，ME），STRADA（Pretzel综合征， ME）、PI3KCA（ME/HME）、AKT3（HME）、PTEN（ME）、DEPDC 5（HME）和RHEB（HME）。常染色体隐性 KPTN（kaptin; 19q13.32）的种系变异，mTOR调节KICSTOR复合物的一部分，已经被 最近在一种临床综合征中发现，这种综合征的特征是ME、智力残疾、自闭症和严重的 癫痫（Baple等人，2014年）在俄亥俄州和宾夕法尼亚州的旧秩序阿米什社区和更多 最近在平原社区外。有8种已确定的致病性KPTN变体（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。 神经系统表型包括婴儿期肌张力减退、自闭症谱系障碍、智力残疾（轻度）、 至重度）和癫痫发作（发作时间在3个月至27岁之间）。癫痫发作通常对标准 医学治疗并且不适合切除手术）。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测量值升高 5.4 SDS）。引人注目的是，对31名儿童进行的一系列OFC测量显示，OFC是典型的 出生时在正常范围内，约75%的患者在出生后前2年内OFC快速增加 OFC >2 SDS。少数病例的神经影像学检查显示， 结构正常的大脑。最近开发了Kptn -/-小鼠品系，目前正在我们的研究中。 实验室令人惊讶的是，Kptn-/-小鼠，而不是Kptn +/-小鼠，也表现出ME表型， 过度生长，因此反映了临床KPTN/MASD表型。本申请提出了3个调查目标 小鼠和人KPTN/MASD表型。在目标1中，我们将定义Kptn CRISPR/Cas9的作用， 体外KO对mTOR通路活化、细胞形态和细胞运动性以及mTOR通路的影响 在小鼠神经祖细胞和神经元中的mTORi抑制剂。在目标2中，我们将分析Kptn -/-脑 包括组织病理学、mTOR信号传导激活和过度兴奋（EEG）以及对mTORi的反应。在 目的3：我们将在现有的和前瞻性收集的KPTN/MASD的神经系统表型中定义KPTN/MASD。 平原社区和一般人群中的个体队列。由于接近 Kptn -/-小鼠模型和人KPTN/MASD之间的表型重叠，这些研究提供了 这是一个独特的机会，为KPTN/MASD的干预性临床试验奠定基础，以防止脑 过度生长