Mutations in ACTL6B cause recessive autism: affected families, mouse model, molecular and circuit mechanisms

ACTL6B 突变导致隐性自闭症：受影响的家庭、小鼠模型、分子和电路机制

• 批准号: 10444846
• 负责人: Wendy Christine Wenderski
• 金额: $ 1.5万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-09 至 2022-03-08
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10444846
• 关键词: ACTL6B gene; Action Potentials; Affect; Agonist; Anatomy; Animal Model; Animals; BRAIN initiative; Behavior; Behavior Control; Biological Assay; Biology; Brain; Child; Chromatin; Chromatin Remodeling Factor; Collaborations; Complex; DNA Sequence Alteration; Data; Development; Disease; Doctor of Philosophy; ERG gene; Epigenetic Process; Etiology; Exhibits; Family; Future; Gene Activation; Gene Silencing; Genes; Genetic; Genetic Transcription; Genome; Genomics; Goals; Heritability; Histone Acetylation; Human; Impairment; Inherited; Investigation; Knockout Mice; Laboratories; Learning; Light; Link; Malignant Neoplasms; Memory; Mentors; Mission; Modeling; Molecular; Mus; Mutate; Mutation; NCOR1 gene; Neurodevelopmental Disorder; Neuronal Plasticity; Neurons; Neurosciences; Nuclear Extract; Pathway interactions; Phase; Phenotype; Population Control; RNA; Repressor Proteins; Research; Research Assistant; Research Project Grants; Research Support; Rest; Risk; Role; Running; Seminal; Serotonin Receptor 5-HT1B; Site; Social Behavior; Synaptic plasticity; System; Testing; Tissues; Training; Transcription Factor AP-1; Treatment Efficacy; United States National Institutes of Health; Universities; Work; XCL1 gene; autism spectrum disorder; autistic behaviour; behavior influence; brain circuitry; cell type; chromatin remodeling; experimental study; genetic regulatory protein; histone modification; insight; mouse model; mutant; neural circuit; neurodevelopment; neuron loss; neuronal circuitry; new therapeutic target; post-doctoral training; relating to nervous system; response; skills; social; social communication impairment; tool; transcription factor

Project Summary Autism spectrum disorder (ASD) is a highly prevalent group of neurodevelopmental disorders whose treatment efficacy is limited by poor understanding of its causal molecular mechanisms. Identifying disease mechanisms in ASD involves overcoming several challenges. First, it is difficult to demonstrate causality for a given mutation, since many mutations increase risk but do not always produce ASD. Second, it is challenging to identify animal models with autism-related phenotypes that are robust across multiple genetic backgrounds. Third, limited understanding of the neuronal subtypes and circuits responsible for behavior is a barrier to studying molecular mechanisms in a disease-relevant cellular context. The proposed research meets all three of these challenges. In the F99 phase, human families with a highly penetrant form of recessive autism caused by mutations in ACTL6B, a neuronal-specific subunit of the BAF chromatin remodeling complex, were identified. Actl6b-/- mice were tested as a model for ACTL6B mutant ASD and found to exhibit autism-related behaviors on two genetic backgrounds and similar brain anatomy to the affected humans. Transcriptional analysis of Actl6b-/- cortical cultures indicated that neural activity-induced genes were de-repressed in the absence of Actl6b, even when action potentials were blocked. The elevated expression of early response genes, including AP1 transcription factors (e.g., Fos, Junb), in Actl6b-/- neurons was associated with increased chromatin accessibility at AP1 sites and activity-related transcriptional changes in late-response genes, implicating abnormal early response gene activation as a potential disease mechanism. The genomic localization of the BAF complex, AP1 transcription factors, and the NCoR complex, which interacted with BAF in cortical tissue, will be studied in wildtype and Actl6b-/- neurons to learn if altered targeting of these complexes may contribute to disease-related transcriptional changes. To gain insight into the affected neuronal circuitry, a serotonin receptor 1b (5HT1b) agonist that was shown to rescue social behavior in the 16p11 autism mouse model (PMID: 30089910) was tested and found to rescue social impairments in Actl6b-/- mice. Serotonergic neuron-specific deletion of Arid1b, the most frequently mutated BAF subunit in autism, caused social impairments in mice that could likewise be rescued with the 5HT1b agonist, indicating that BAF function in serotonergic neurons is critical for social behavior. These studies have inspired the postdoctoral (K00) research direction: to interrogate autism-related molecular mechanisms within neuronal populations that control behavior. The postdoctoral training in systems neuroscience will buoy future studies linking the functions of chromatin regulatory proteins directly to behavior. This research supports the missions of the NIH Blueprint and BRAIN Initiative by providing new tools for autism research and revealing molecular and circuit mechanisms that influence behavior.

项目摘要 自闭症谱系障碍（ASD）是一组高度流行的神经发育障碍，其治疗 由于对其致病分子机制的理解不足，其功效受到限制。确定疾病机制 ASD的治疗需要克服几个挑战。首先，很难证明给定的 突变，因为许多突变增加风险，但并不总是产生ASD。第二，具有挑战性， 识别具有自闭症相关表型的动物模型，这些表型在多种遗传背景下都是稳健的。 第三，对负责行为的神经元亚型和回路的有限理解是一个障碍， 研究疾病相关细胞背景下的分子机制。拟议的研究符合所有三个 这些挑战。在F99阶段，具有高度外显形式的隐性自闭症的人类家庭引起了 通过BAF染色质重塑复合物的神经元特异性亚基ACTL 6 B的突变， 鉴定将Actl 6 b-/-小鼠作为ACTL 6 B突变型ASD的模型进行测试，发现其表现出自闭症相关的自闭症。 两种遗传背景的行为和类似的大脑解剖受影响的人类。转录 对Act 16 b-/-皮层培养物的分析表明，神经活性诱导的基因在神经细胞中被去抑制。 Act 16 b的缺乏，即使当动作电位被阻断时。早期反应的表达升高 基因，包括AP 1转录因子（例如，Fos，Junb），在Act 16 b-/-神经元中与增加的 AP 1位点的染色质可及性和晚期反应基因中活性相关的转录变化， 暗示异常的早期反应基因激活是潜在的疾病机制。基因组 与BAF相互作用的BAF复合物、AP 1转录因子和NCoR复合物的定位 在皮质组织中，将在野生型和Act 16 b-/-神经元中进行研究，以了解这些神经元的靶向是否改变。 复合物可能有助于疾病相关的转录变化。为了深入了解受影响的神经元 回路，一种5-羟色胺受体1b（5 HT 1b）激动剂，被证明可以挽救16 p11中的社会行为。 测试了自闭症小鼠模型（PMID：30089910），发现其挽救了Act 16 b-/-小鼠中的社交障碍。 5-羟色胺能神经元特异性缺失Arid 1b，自闭症中最常见的突变BAF亚基，导致 同样可以用5 HT 1b激动剂挽救的小鼠的社会障碍，表明BAF功能 对社会行为至关重要。这些研究启发了博士后（K 00） 研究方向：探讨神经元群体中自闭症相关的分子机制， 控制行为系统神经科学的博士后培训将推动未来的研究， 染色质调节蛋白的功能直接影响行为。这项研究支持了 通过为自闭症研究提供新的工具，揭示自闭症的分子和 影响行为的电路机制。