Investigating molecular mechanisms and treatments for CTNNB1 Syndrome using mouse and human models

使用小鼠和人类模型研究 CTNNB1 综合征的分子机制和治疗方法

基本信息

批准号：
10307411
负责人：
Michele H. Jacob
金额：
$ 47.07万
依托单位：
TUFTS UNIVERSITY BOSTON
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-07-01 至 2023-12-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10307411
关键词：
Address Adhesions Adverse effects Affect Age Alleles Brain CTNNB1 gene Cadherins Cell Culture Techniques Cell Line Cell model Cells Cerebrum Child Childhood Clustered Regularly Interspaced Short Palindromic Repeats Cognitive Collaborations Complex Critical Pathways Deletion Mutation Development Developmental Delay Disorders Diagnosis Disease Disease model Distal Dose Electrophysiology (science)Exhibits Felis catus Fragile X Syndrome Gait Gene Mutation Glutamates Glycogen Synthase Kinase 3 Goals Hand Strength Heterozygote Human Impaired cognition Impairment In Vitro Institutes Intellectual functioning disability Knowledge Language Learning Link Lithium Mass Spectrum Analysis Membrane Potentials Microcephaly Modeling Molecular Motor Motor Neurons Mus Muscle Muscle Cells Muscle Fibers Muscle Hypertonia Muscle function Muscle hypotonia Mutate Mutation Na(+)-K(+)-Exchanging ATPase Nerve Neurons Outcome Pathologic Pharmaceutical Chemistry Pharmaceutical Preparations Pharmacotherapy Phenotype Phosphorylation Pilot Projects Play Point Mutation Pre-Clinical Model Prosencephalon Proteomics Quality of life Regimen Rest Rett Syndrome Signal Transduction Pathway Skeletal Muscle Spastic Gait Spinal Spinal Cord Symptoms Synapses Syndrome Testing Tissues WNT Signaling Pathway base behavior test cell type classical conditioning developmental disease disability drug efficacy drug testing efficacy testing exome sequencing genetic testing human model human pluripotent stem cell improved in vivo induced pluripotent stem cell inhibitor/antagonist insight loss of function motor deficit motor learning mouse model multidisciplinary neuromuscular next generation novel paralogous gene pilot trial prevent reduced muscle strength relating to nervous system risk variant skeletal therapeutically effective treatment duration

项目摘要

CTNNB1 Syndrome is a developmental disorder characterized by intellectual disabilities, microcephaly, global developmental delays (motor, language) and motor disabilities (truncal muscle hypotonia, distal hypertonia with spastic gait). It is caused by CTNNB1 (Beta-catenin) haploinsufficiency due to partial or complete deletion mutations. CTNNB1 is a significant risk gene for intellectual disabilities. Several other human gene mutations also cause reduced Beta-catenin levels or functions and similar developmental disorders. Beta-catenin plays key roles in two pathways critical for proper neural and neuromuscular development and function- the canonical Wnt signal transduction pathway and cadherin-based synaptic adhesion complexes. Treatments for CTNNB1 Syndrome are lacking due to limited knowledge of the underlying pathophysiological mechanisms, limited studies of CTNNB1 heterozygous mice and as yet no human cell models. We propose in vivo mouse and in vitro human cell studies to address these critical gaps. Preliminary studies of our CTNNB1 germline heterozygous mouse show phenotypes relevant to this disorder, impaired associative and motor learning, and reduced muscle grip strength, compared with control littermates. Our Aim 1 studies will provide novel mechanistic insights by identifying in vivo molecular and functional changes in three tissue types relevant to CTNNB1 syndrome features: forebrain, spinal cord and skeletal muscle. We will use multi-disciplinary quantitative approaches, mass spectrometry proteomics, electrophysiological recordings, and further behavioral testing for altered cognitive and motor capabilities. Our Aim 2 studies will utilize the in vivo mouse model to test our hypothesis that drug treatments that normalize Beta-catenin levels will improve or remedy the phenotypes caused by Beta-catenin haploinsufficiency. We will test drug treatments that have been shown to increase Beta-catenin levels and improve learning and motor deficits in mouse models of other disorders with similar phenotypes to CTNNB1 syndrome. To increase translational relevance, Aim 3 studies will generate human cell models of CTNNB1 heterozygous loss-of-function in multiple cell types relevant to CTNNB1 syndrome features: cortical glutamatergic neurons, spinal motoneurons and skeletal myotubes. We will also generate isogenic revertant controls with the mutated allele corrected. We will define molecular changes caused by reduced Beta-catenin, using mass spectrometry proteomics. We will test the efficacy of drug treatments for correction of Beta-catenin and the molecular changes. Our findings will identify both shared and unique molecular alterations between the in vitro human cells and the corresponding in vivo mouse tissue types. Shared changes will identify core pathophysiological mechanisms. We may also identify novel components of the Beta-catenin network in the different tissues. Our studies will provide critical proof-of-concept in two preclinical models for the potential of drug treatments to ameliorate phenotypes of CTNNB1 syndrome and improve quality of life for affected children.

CTNNB1 综合征是一种发育障碍，其特征为智力障碍、小头畸形、整体发育迟缓（运动、语言）和运动障碍（躯干肌张力减退、远端张力亢进伴痉挛步态）。它是由部分或完全缺失突变导致的 CTNNB1（β-连环蛋白）单倍体不足引起的。 CTNNB1 是智力障碍的重要风险基因。其他几种人类基因突变也会导致β-连环蛋白水平或功能降低以及类似的发育障碍。 β-连环蛋白在对神经和神经肌肉正常发育和功能至关重要的两条通路中发挥着关键作用——经典的 Wnt 信号转导通路和基于钙粘蛋白的突触粘附复合物。由于对潜在病理生理机制的了解有限、对 CTNNB1 杂合子小鼠的研究有限且尚未建立人类细胞模型，因此缺乏 CTNNB1 综合征的治疗方法。我们建议进行体内小鼠和体外人类细胞研究来解决这些关键差距。对我们的 CTNNB1 种系杂合小鼠的初步研究显示，与对照同窝小鼠相比，与这种疾病相关的表型、联想和运动学习受损以及肌肉握力降低。我们的目标 1 研究将通过识别与 CTNNB1 综合征特征相关的三种组织类型（前脑、脊髓和骨骼肌）的体内分子和功能变化，提供新颖的机制见解。我们将使用多学科定量方法、质谱蛋白质组学、电生理记录以及进一步的行为测试来改变认知和运动能力。我们的目标 2 研究将利用体内小鼠模型来检验我们的假设，即使 β-连环蛋白水平正常化的药物治疗将改善或补救由 β-连环蛋白单倍体不足引起的表型。我们将在患有与 CTNNB1 综合征表型相似的其他疾病的小鼠模型中测试药物治疗，这些药物治疗已被证明可以提高 β-连环蛋白水平并改善学习和运动缺陷。为了提高转化相关性，Aim 3 研究将在与 CTNNB1 综合征特征相关的多种细胞类型中生成 CTNNB1 杂合功能丧失的人类细胞模型：皮质谷氨酸能神经元、脊髓运动神经元和骨骼肌管。我们还将生成校正突变等位基因的同基因回复突变对照。我们将使用质谱蛋白质组学来定义由β-连环蛋白减少引起的分子变化。我们将测试药物治疗纠正β-连环蛋白和分子变化的功效。我们的研究结果将鉴定体外人类细胞和相应的体内小鼠组织类型之间共有和独特的分子改变。共同的变化将确定核心的病理生理机制。我们还可以在不同组织中识别β-连环蛋白网络的新成分。我们的研究将为两个临床前模型提供关键的概念验证，证明药物治疗有可能改善 CTNNB1 综合征的表型并提高受影响儿童的生活质量。