Cortical Interneuron Dysfunction in Fragile X Syndrome

脆性 X 综合征中的皮质中间神经元功能障碍

• 批准号: 10418431
• 负责人: Anis Contractor
• 金额: $ 51.27万
• 依托单位: UNIVERSITY OF CALIFORNIA LOS ANGELES
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-04-01 至 2027-02-28
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10418431
• 关键词: Acute; Adaptive Behaviors; Address; Adult; Affect; Animal Model; Animals; Apoptosis; Behavior; Biological Assay; Birth; Brain; Bromodeoxyuridine; Calcium; Caspase; Cell Death; Cell Density; Cells; Cessation of life; Characteristics; Chronic; Collaborations; Contractor; Data; Development; Experimental Designs; FMR1; Fragile X Syndrome; Functional disorder; Ganglia; Genes; Genetic; Goals; Grant; Hypersensitivity; Image; Impairment; In Vitro; Individual; Intellectual functioning disability; Interneurons; Knock-out; Knockout Mice; Laboratories; Maps; Medial; Mus; Neurodevelopmental Disorder; Neurologic Symptoms; Neurons; Parvalbumins; Perceptual learning; Pharmaceutical Preparations; Phenocopy; Phenotype; Pyramidal Cells; Quality of life; Reporting; Rhodopsin; Sensory; Slice; Somatosensory Cortex; Somatostatin; Symptoms; Tactile; Testing; Therapeutic; Time; Universities; Vibrissae; Work; autism spectrum disorder; avoidance behavior; cell type; critical period; density; designer receptors exclusively activated by designer drugs; hippocampal pyramidal neuron; in vivo; in vivo calcium imaging; interdisciplinary approach; loss of function; mature animal; migration; mouse model; nerve stem cell; neurogenesis; novel; patch clamp; postnatal; response; small molecule; therapeutic target; tool; translational study; two-photon

SUMMARY Cortical circuit dysfunction is a primary pathophysiology that underlies prominent neurological symptoms of Fragile X Syndrome (FXS). Yet the precise way in which circuit development in the cortex is altered in FXS has not been fully elucidated. Recent work by us, and others, has established that local circuit interneurons (INs) may be a key to understanding cortical circuits in FXS. We demonstrated that the density, maturity and activity of parvalbumin (PV) cortical INs are all reduced in the Fmr1 knockout (KO) mouse model of FXS. Here we propose to address outstanding questions in the field by determining how the birth, migration and connectivity of PV INs are disrupted in Fmr1 KO mice, and how this leads to sensory hypersensitivity and tactile defensiveness. We will incorporate a detailed analysis of PV INs using birth dating, neuroanatomical and functional studies to define how the abnormal integration of PV INs into feedforward circuits in the primary somatosensory cortex (S1) contributes to atypical sensory processing. In preliminary studies, we demonstrate that, in response to repetitive whisker stimulation, Fmr1 KO mice display maladaptive avoidance behaviors that correlate with a lack of neuronal adaptation of layer (L) 2/3 pyramidal neurons in S1. We also show that PV INs and their precursors from the medial ganglionic eminence (MGE) are hypoactive in S1 of Fmr1 KO mice by postnatal day (P) 6, and that increasing their activity for a few days using excitatory DREADDs significantly increases their density by P15. We will now determine whether similar early activity manipulations of MGE-derived INs, or later on in more mature PV INs, can restore the loss of sensory adaptation of L2/3 neurons and ameliorate tactile defensiveness in Fmr1 KO mice. We will address the following important questions: 1. What are the contributions of neurogenesis, migration, connectivity and developmental apoptosis to the reduced density of PV INs in FXS? 2. How do MGE-derived INs and pyramidal neurons interact during the early postnatal critical period and how is their ‘handshake’ different in FXS? 3. Is the hypoactivity of PV INs or their precursors causal to the circuit and behavior deficits of Fmr1 KO mice? The mechanistic experimental design employs cell type-specific intersectional genetics, in vivo calcium imaging, chemogenetics, and ex vivo circuit channel-rhodopsin connectivity mapping, among others. An important goal of this grant is to identify whether targeting INs is a viable path for therapeutics in FXS. As such a novel class of allosteric modulating drugs of Kv3.1 channels (responsible for fast-spiking characteristics of PV INs) will be tested in Fmr1 KO mice. Overall, the collaboration between the laboratories of Dr. Carlos Portera-Cailliau (co-PI, PL) at UCLA and Dr. Anis Contractor (co-PI) at Northwestern University will enable a comprehensive approach to understanding the developmental and functional contributions of INs to the pathophysiology of FXS.

概括 皮质回路功能障碍是一种主要的病理生理学，是以下疾病突出神经系统症状的基础： 脆性 X 综合症 (FXS)。然而，FXS 改变了皮质电路发展的精确方式 尚未完全阐明。我们和其他人最近的工作已经确定局部电路中间神经元 (IN) 可能是理解 FXS 中皮质回路的关键。我们证明了密度、成熟度 Fmr1 敲除 (KO) 小鼠模型中小清蛋白 (PV) 皮质 IN 和活性均降低 FXS。在这里，我们建议通过确定出生、移民如何解决该领域的突出问题。 Fmr1 KO 小鼠中 PV IN 的连接被破坏，以及这如何导致感觉超敏反应 和触觉防御。我们将使用出生日期对 PV IN 进行详细分析， 神经解剖学和功能研究，以确定 PV IN 的异常整合如何进入前馈 初级体感皮层 (S1) 中的回路有助于非典型的感觉处理。在初步 研究中，我们证明，响应重复的胡须刺激，Fmr1 KO 小鼠表现出 与 (L) 2/3 锥体层神经元适应缺乏相关的适应不良回避行为 S1 中的神经元。我们还表明 PV IN 及其前体来自内侧神经节隆起 (MGE) Fmr1 KO 小鼠的 S1 在出生后第 6 天 (P) 时活性降低，并且少数小鼠的活性增加 使用兴奋性 DREADD 的天数显着增加其密度 P15。我们现在将确定是否 对 MGE 衍生的 IN 进行类似的早期活性操作，或者稍后在更成熟的 PV IN 中进行类似的活性操作，可以恢复 Fmr1 KO 小鼠 L2/3 神经元感觉适应丧失并改善触觉防御能力。我们将 解决以下重要问题： 1. 神经发生、迁移、 连接和发育凋亡与 FXS 中 PV IN 密度降低有关？ 2. MGE如何衍生 INs和锥体神经元在产后早期关键期相互作用以及它们如何“握手” FXS 有何不同？ 3. PV IN 或其前体的活动减退是否会导致电路和行为缺陷 Fmr1 KO 小鼠？机械实验设计采用细胞类型特异性交叉遗传学， 体内钙成像、化学遗传学和离体电路通道-视紫红质连接图谱等 其他的。这笔赠款的一个重要目标是确定靶向 IN 是否是治疗以下疾病的可行途径 FXS。作为这样一类新型的 Kv3.1 通道变构调节药物（负责快速尖峰） PV IN 的特征）将在 Fmr1 KO 小鼠中进行测试。总体而言，实验室之间的合作 加州大学洛杉矶分校 Carlos Portera-Cailliau 博士（联合 PI、PL）和西北大学 Anis Contractor 博士（联合 PI） 将能够采用全面的方法来理解发育和功能的贡献 FXS 病理生理学的 INs。