Molecular and circuit defects underlying different SCN2A mutations and ASDs

不同 SCN2A 突变和自闭症谱系障碍 (ASD) 背后的分子和电路缺陷

• 批准号: 10596085
• 负责人: Geoffrey S Pitt
• 金额: $ 64.34万
• 依托单位: WEILL MEDICAL COLL OF CORNELL UNIV
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-06-07 至 2025-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10596085
• 关键词: Action Potentials; Adult; Affect; Amygdaloid structure; Axon; Behavior; Behavioral; Biological Assay; Brain; C-terminal; CRISPR/Cas technology; Calmodulin; Cells; Characteristics; Clinical; Compensation; Data; Defect; Detection; Development; Diagnosis; Disease model; Distal; Electrophysiology (science); Equilibrium; Fiber; Functional disorder; Funding; Genes; Genetic; Goals; Impairment; Interneurons; Link; Modeling; Molecular; Mus; Mutation; Neocortex; Neurons; Outcome; Output; Photometry; Point Mutation; Property; Protein Truncation; Reporting; Roentgen Rays; SCN2A protein; SCN8A gene; Social Behavior; Social Interaction; Sodium Channel; Structure; Synapses; Techniques; Testing; Therapeutic; Variant; Weaning; anxiety-like behavior; autism spectrum disorder; behavioral phenotyping; designer receptors exclusively activated by designer drugs; effective therapy; endophenotype; excitatory neuron; exome sequencing; genomic locus; in vivo; insight; loss of function; loss of function mutation; mouse model; mutant; neocortical; neural circuit; neuronal excitability; novel; restoration; social deficits; tool; voltage

ABSTRACT The recent wave of whole exome sequencing studies places SCN2A, which encodes the neuronal voltage- gated Na+ channel pore-forming α subunit NaV1.2, near top of the list of genetic loci linked to autism spectrum disorders (ASDs). On the one hand, that NaV1.2 is an essential Na+ channel responsible for initiating action potentials within excitatory neurons in the developing brain provides a rationale for the prominence of SCN2A. On the other, most SCN2A mutations associated with ASDs are loss-of-function and predicted to decrease neuronal excitability, an outcome that would lower the neocortical excitation/inhibition (E/I) balance and thus contrast with the generally accepted model that behavior defects in ASDs, such as social dysfunction, result from an increased E/I balance. This conundrum persists because of the absence of Scn2a mouse models that reveal ASD-associated endophenotypes, thus limiting our ability to dissect the cellular electrophysiological defects associated with Scn2a loss-of-function mutations and the consequent circuit level dysfunctions that lead to ASD-associated behaviors. Building on x-ray crystal structures of key regulatory components of NaV1.2 that we solved and analyzed during the previous funding period, we obtained specific insights into how ASD- associated mutations in NaV1.2 perturb channel function and alter E/I balance. Further, we generated two novel Scn2a mouse models by CRISPR/Cas9 to test the specific contribution of Scn2a mutations in vivo. Initial analyses of these models reveal abnormal Na+ channel function, decreased cortical neuron excitability, and dysfunctional behaviors consistent with ASDs, while simultaneously demonstrating informative differences between the two models. These models provide a unique set of tools that will allow us to trace abnormal channel function through altered neuronal electrical activity to the consequent circuit-level dysfunction and the resulting ASD endophenotypes. We propose to exploit these novel Scn2a mutant models for the following Aims: 1) We will obtain detailed information about their neuronal electrophysiological characteristics and synaptic properties, thereby defining how Scn2a mutations perturb neuronal function. 2) We will employ fiber photometry and chemogenetic tools (DREADDs) to test whether the Scn2a mutations decrease excitatory drive to the basolateral amygdala and thereby produce the social dysfunction and impaired danger detection observed in our Scn2a mouse models. 3) We will exploit our initial electrophysiological findings to test a potential therapeutic strategy in which we aim to counteract the reduced Na+ current associated with ASD-associated SCN2A loss-of-function mutations. Our overall goals are to define the range of cellular dysfunction that results from Scn2a mutations and trace those abnormalities through the circuit level to behavioral manifestations.

ABSTRACT The recent wave of whole exome sequencing studies places SCN2A, which encodes the neuronal voltage- gated Na+ channel pore-forming α subunit NaV1.2, near top of the list of genetic loci linked to autism spectrum disorders (ASDs). On the one hand, that NaV1.2 is an essential Na+ channel responsible for initiating action potentials within excitatory neurons in the developing brain provides a rationale for the prominence of SCN2A. On the other, most SCN2A mutations associated with ASDs are loss-of-function and predicted to decrease neuronal excitability, an outcome that would lower the neocortical excitation/inhibition (E/I) balance and thus contrast with the generally accepted model that behavior defects in ASDs, such as social dysfunction, result from an increased E/I balance. This conundrum persists because of the absence of Scn2a mouse models that reveal ASD-associated endophenotypes, thus limiting our ability to dissect the cellular electrophysiological defects associated with Scn2a loss-of-function mutations and the consequent circuit level dysfunctions that lead to ASD-associated behaviors. Building on x-ray crystal structures of key regulatory components of NaV1.2 that we solved and analyzed during the previous funding period, we obtained specific insights into how ASD- associated mutations in NaV1.2 perturb channel function and alter E/I balance. Further, we generated two novel Scn2a mouse models by CRISPR/Cas9 to test the specific contribution of Scn2a mutations in vivo. Initial analyses of these models reveal abnormal Na+ channel function, decreased cortical neuron excitability, and dysfunctional behaviors consistent with ASDs, while simultaneously demonstrating informative differences between the two models. These models provide a unique set of tools that will allow us to trace abnormal channel function through altered neuronal electrical activity to the consequent circuit-level dysfunction and the resulting ASD endophenotypes. We propose to exploit these novel Scn2a mutant models for the following Aims: 1) We will obtain detailed information about their neuronal electrophysiological characteristics and synaptic properties, thereby defining how Scn2a mutations perturb neuronal function. 2) We will employ fiber photometry and chemogenetic tools (DREADDs) to test whether the Scn2a mutations decrease excitatory drive to the basolateral amygdala and thereby produce the social dysfunction and impaired danger detection observed in our Scn2a mouse models. 3) We will exploit our initial electrophysiological findings to test a potential therapeutic strategy in which we aim to counteract the reduced Na+ current associated with ASD-associated SCN2A loss-of-function mutations. Our overall goals are to define the range of cellular dysfunction that results from Scn2a mutations and trace those abnormalities through the circuit level to behavioral manifestations.

项目成果

L-type calcium channels and neuropsychiatric diseases: Insights into genetic risk variant-associated genomic regulation and impact on brain development.

• DOI: 10.1080/19336950.2023.2176984
• 发表时间: 2023-12
• 期刊: CHANNELS
• 影响因子: 3.3
• 作者: Baker, Madelyn R.;Lee, Andrew D. S.;Rajadhyaksha, Anjali M.
• 通讯作者: Rajadhyaksha, Anjali M.

Scn2a severe hypomorphic mutation decreases excitatory synaptic input and causes autism-associated behaviors.

• DOI: 10.1172/jci.insight.150698
• 发表时间: 2021-08-09
• 期刊: JCI insight
• 影响因子: 8
• 作者: Wang HG;Bavley CC;Li A;Jones RM;Hackett J;Bayleyen Y;Lee FS;Rajadhyaksha AM;Pitt GS
• 通讯作者: Pitt GS

Direct Observation of Compartment-Specific Localization and Dynamics of Voltage-Gated Sodium Channels.

• DOI: 10.1523/jneurosci.0086-22.2022
• 发表时间: 2022-07-13
• 期刊: JOURNAL OF NEUROSCIENCE
• 影响因子: 5.3
• 作者: Liu, Hui;Wang, Hong-Gang;Pitt, Geoffrey;Liu, Zhe
• 通讯作者: Liu, Zhe