Physiological and molecular mechanisms of impaired PV circuit homeostasis in Autism mouse models

自闭症小鼠模型中PV电路稳态受损的生理和分子机制

• 批准号: 10569470
• 负责人: Hannah Monday
• 金额: $ 7.2万
• 依托单位: UNIVERSITY OF CALIFORNIA BERKELEY
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-02-01 至 2025-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10569470
• 关键词: Affect; Behavioral; CRISPR/Cas technology; Cells; Clustered Regularly Interspaced Short Palindromic Repeats; Data; Defect; Disease model; ETV1 gene; Electrophysiology (science); Exhibits; FMR1; Failure; Feedback; Functional disorder; Gene Expression; Genetic Models; Genetic Transcription; Homeostasis; Human; Hypersensitivity; Impairment; In Vitro; Interneurons; Knowledge; Measurement; Measures; Mediating; Messenger RNA; Methods; Modeling; Molecular; Molecular Target; Mus; Neurons; Parvalbumins; Pathway interactions; Phenotype; Physiological; Physiology; Potassium; Protein Biosynthesis; Proteins; Pyramidal Cells; Reporting; Sensory; Signal Pathway; Site; Somatosensory Cortex; Source; Synapses; Tactile; Testing; Therapeutic; Therapeutic Intervention; Touch sensation; Translating; Vibrissae; Wild Type Mouse; autism spectrum disorder; deprivation; genetic approach; genome editing; in vivo; individuals with autism spectrum disorder; insight; mouse model; novel; novel therapeutic intervention; optogenetics; posttranscriptional; sensory cortex; sensory feedback; sensory input; sensory stimulus; transcription factor; voltage

PROJECT SUMMARY Parvalbumin (PV) neuron hypofunction and increased excitation-inhibition (E-I) ratio in feedforward cortical circuits likely contribute to abnormal sensory processing in Autism Spectrum Disorders, but the origins and molecular mechanisms of PV hypofunction, and its generalizability beyond feedforward circuits, remain unclear. Here, I will test the hypothesis that PV circuit hypofunction arises because of impaired homeostatic plasticity of PV circuits, that normally acts to maintain cortical excitability during periods of shifting sensory input. In L2/3 of whisker primary somatosensory cortex (S1), PV circuit homeostasis is robustly engaged by brief whisker deprivation, which reduces intrinsic excitability of PV neurons, decreasing feedforward inhibition. In Aim 1.1, I will use in vitro electrophysiological measurements of PV cell excitability to test for impaired PV circuit homeostasis in two ASD mouse models (Fmr1-/y and Tsc2+/-). These models share PV hypofunction but differ in several molecular and synaptic phenotypes, making them a powerful test case for whether the PV hypofunction may arise from a common source. Previous physiological studies have primarily focused on dysfunction in bottom-up feedforward circuits in ASDs, but recent reports in people with ASDs suggest that sensory processing issues may result from a functional deficiency in top-down feedback pathways, resulting in overreliance on feedforward input. Top-down pathways provide strong input to S1, but it is unknown whether the physiology of feedback pathways is altered in ASD mouse models and whether their alteration may also result from a failure of homeostasis in PV cells. In Aims 1.2 & 1.3, I will assess changes in baseline function and homeostatic plasticity of S2->S1 inputs to L2/3 pyramidal and PV cells in S1 using optogenetics. Understanding the molecular mechanisms that underlie impaired PV circuit homeostasis in ASDs may enable therapeutic interventions to restore PV circuit function. These molecular mechanisms are currently unknown. I will identify the molecular mechanisms underlying deprivation-induced weakening of PV intrinsic excitability, the key initial step in PV homeostasis. This is known to involve an increase in voltage-gated potassium (Kv) channel currents. The molecular mechanisms likely involve activity-dependent protein synthesis, which is reportedly dysregulated in both the Fmr1-/y and Tsc2+/- mice, though potentially in opposite directions. A promising candidate signaling pathway that could mediate PV circuit homeostasis is activity- dependent synthesis of transcription factor ER81 leading to increased Kv1.1 expression in PV cells. In Aim 2, I will use novel cell-specific genetic strategies to test the hypothesis that PV circuit homeostasis requires protein synthesis in vivo and involves activity-dependent synthesis of ER81 and increased Kv1.1- and this is impaired in ASD mice. I will also develop CRISPR tools to modulate Kv1.1 levels to rescue PV homeostasis in ASD mice, potentially leading to therapeutic approaches for ASDs.

项目摘要 小白蛋白（PV）神经元功能减退和前馈中兴奋-抑制（E-I）比增加 皮质回路可能有助于自闭症谱系障碍的异常感觉处理，但起源于 PV功能减退的分子机制及其超越前馈回路的普遍性仍然存在 不清楚在这里，我将测试的假设，PV电路功能减退，因为受损的稳态 PV电路的可塑性，通常在感觉转换期间维持皮质兴奋性 输入.在L2/3的触须初级体感皮层（S1），PV回路的稳态是由 短暂的胡须剥夺，降低PV神经元的内在兴奋性，减少前馈抑制。 在目标1.1中，我将使用PV细胞兴奋性的体外电生理测量来测试受损的PV 在两种ASD小鼠模型（Fmr 1-/y和Tsc 2 +/-）中的回路稳态。这些模型具有PV功能减退， 不同的几个分子和突触表型，使他们成为一个强大的测试案例，是否PV 功能减退可能由共同的原因引起。 以前的生理学研究主要集中在自下而上前馈回路的功能障碍上 但是最近关于ASD患者的报告表明，感觉处理问题可能是由于 自上而下反馈途径的功能缺陷，导致过度依赖前馈输入。顶向下 通路为S1提供强有力的输入，但反馈通路的生理学是否被改变尚不清楚 以及它们的改变是否也可能由PV细胞内稳态的失败引起。在 目的1.2和1.3，我将评估基线功能和稳态可塑性的变化S2->S1输入L2/3 使用光遗传学在S1中的锥体细胞和PV细胞。 了解ASD患者肺静脉回路稳态受损的分子机制， 使治疗干预能够恢复PV回路功能。这些分子机制目前 未知我将确定剥夺诱导PV内在减弱的分子机制， 兴奋性，PV稳态的关键初始步骤。这是已知的涉及增加电压门控 钾离子通道电流。其分子机制可能涉及活性依赖蛋白 合成，据报道在Fmr 1-/y和Tsc 2 +/-小鼠中均失调，尽管可能相反， 方向一个有希望的候选信号通路，可以介导PV电路稳态是活动- 转录因子ER 81的依赖性合成导致PV细胞中Kv1.1表达增加。在目标2中，我 将使用新的细胞特异性遗传策略来测试PV回路稳态需要蛋白质的假设， 在体内合成，并涉及ER 81的活性依赖性合成和增加Kv1.1-这是受损 自闭症小鼠的实验我还将开发CRISPR工具来调节Kv1.1水平，以挽救ASD中的PV稳态 小鼠，可能导致ASD的治疗方法。