Targeting Serotonin 5-HT1A and 5-HT7 Receptors to Prevent Audiogenic Seizures and Correct Translationally Valid EEG Phenotypes in a Juvenile Fmr1 Knock-Out Mouse Model of Fragile X Syndrome

靶向血清素 5-HT1A 和 5-HT7 受体以预防脆性 X 综合征幼年 Fmr1 敲除小鼠模型中的听源性癫痫发作并纠正翻译有效的脑电图表型

• 批准号: 10046961
• 负责人: CLINTON E CANAL
• 金额: $ 42.45万
• 依托单位: MERCER UNIVERSITY MACON
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-08-01 至 2024-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10046961
• 关键词: ARHGEF5 gene; Adenylate Cyclase; Adolescent; Adult; Affect; Age; Agonist; Area; Attention; Attenuated; Auditory area; Binding; Biological Assay; Biological Markers; Biological Psychiatry; Blood Platelets; Brain; Child; Clinical Trials; Combined Modality Therapy; Cyclic AMP; Data; Data Reporting; Development; Dose; Electrodes; Electroencephalogram; Epilepsy; Equilibrium; Etiology; Exhibits; FMR1; FMRP; Fragile X Syndrome; Frequencies; Functional disorder; GTP-Binding Protein alpha Subunits, Gs; GTP-Binding Proteins; Grant; High Prevalence; Hippocampus (Brain); Hypersensitivity; Individual; Infrastructure; Inherited; Intellectual functioning disability; Knockout Mice; Knowledge; Link; Literature; Medicine; Membrane; Methods; Minor; Modeling; Mus; Mutation; Outcome; Patients; Peripheral; Pharmacodynamics; Pharmacology; Phenotype; Population; Predisposition; Prevalence; Property; Regulation; Reporting; Rest; Seizures; Sensory; Serotonergic System; Serotonin; Signal Transduction; Somatosensory Cortex; System; Testing; Translating; Up-Regulation; Wild Type Mouse; audiogenic seizure; autism spectrum disorder; autistic children; base; behavioral pharmacology; dravet syndrome; experimental study; genetic risk factor; in vivo; inhibitor/antagonist; male; mouse model; neurodevelopment; neuropathology; neuroregulation; neurotransmission; novel; prevent; psychiatric symptom; radioligand; receptor; relating to nervous system; reuptake; serotonin 7 receptor; serotonin receptor; tool

Seizures occur in ~12% of individuals with autism spectrum disorder (ASD) and in ~25% of individuals with fragile X syndrome (FXS)—mutations in FMR1 that cause FXS are also the most common, known genetic risk factor for ASD. Seizure susceptibility in ASD and FXS is higher in children than in adults, inferring a critical neurodevelopmental window. Juvenile Fmr1 knock-out mice, useful for the study of FXS and ASD, exhibit robust sensory-evoked, audiogenic seizures, a phenotype that models sensory hypersensitivity and seizures in individuals with FXS. New studies show that individuals with FXS and Fmr1 knock-out mice also have perturbations in electroencephalogram (EEG) activity at rest, e.g., increased gamma power in the cortex, which we reproduced and report here as preliminary data. Thus, etiologically-valid, Fmr1 knock-out mice exhibit two phenotypes with translational relevance to individuals with FXS. Numerous studies have reported alterations in the serotonin (5-hydroxytryptamine, 5-HT) system in FXS and ASD, yet knowledge regarding the impact of specific 5-HT receptors (5-HTRs) on FXS phenotypes are conspicuously lacking. We now report data showing that audiogenic seizures in juvenile Fmr1 knock-out mice are entirely prevented by a novel 5-HTR modulator with 5-HT1AR and 5-HT7R partial agonist activity. Herein, we propose definitive in vivo behavioral pharmacology and EEG experiments together with ex vivo receptor pharmacology experiments to mechanistically probe 5-HT1ARs and 5-HT7Rs as targets that can prevent audiogenic seizures (Aim 1) and correct EEG abnormalities (Aim 2) in juvenile Fmr1 knock-out mice. We hypothesize in Aim 1 that selective 5-HT1AR activation or selective 5-HT7R inactivation will attenuate audiogenic seizures and combined 5-HT1AR activation/5-HT7R inactivation will prevent audiogenic seizures in juvenile Fmr1 knock-out mice. We extend the test of this hypothesis in Aim 2, testing this pharmacodynamic effect to correct EEG phenotypes, e.g. to correct abnormally high gamma band power in the auditory cortex and somatosensory cortex of juvenile Fmr1 knock-out mice. 5-HT1ARs and 5-HT7Rs are densely expressed in the hippocampus, a neural system with a low seizure threshold that is altered in Fmr1 knock-out mice and in individuals with FXS. In Aim 3, selective radioligands will be used for saturation binding experiments to evaluate 5-HT1AR and 5-HT7R expression in the hippocampus, and [35S]GTPγS assays will be conducted to determine the function of 5-HT1ARs and 5-HT7Rs in the hippocampus of juvenile Fmr1 knock-out mice compared to wild-type mice. 5-HT1ARs and 5-HT7Rs couple to regulate adenylate cyclase activity in opposing ways, i.e., 5-HT1ARs stimulate Gαi, whereas 5-HT7Rs stimulate Gαs signaling. Since cAMP is known to be altered in FXS and ASD, outcomes from this project will provide knowledge to build a critical infrastructure regarding the putative impact of 5-HTR regulation of cAMP on translationally-valid FXS and ASD phenotypes. Results will also provide important information regarding whether 5-HT1ARs and/or 5-HT7Rs are viable pharmacotherapeutic targets for FXS or ASD.

约12%的自闭症谱系障碍患者(ASD)和约25%的自闭症谱系障碍患者(ASD)发生癫痫发作 脆性X综合征(FXS)--导致FXS的FMR1突变也是最常见的已知遗传风险 ASD的因素。儿童ASD和FXS的癫痫易感性高于成人，推测 神经发育窗口。幼年Fmr1基因敲除小鼠，对FXS和ASD的研究有用，展示 强健的感觉诱发的听源性癫痫，一种模拟感觉过敏和癫痫发作的表型 患有FXS的个人。新的研究表明，携带FXS和Fmr1基因敲除小鼠的个体也有 安静时脑电(EEG)活动的扰动，例如大脑皮层伽马功率增加，这 我们在这里转载和报告了初步数据。因此，在病原学上有效的Fmr1基因敲除小鼠表现出两个 与FXS患者有翻译相关性的表型。许多研究已经报告了在 5-羟色胺(5-羟色胺，5-羟色胺)系统在FXS和ASD中的作用 FXS表型的特异性5-羟色胺受体(5-HTR)明显缺乏。我们现在报告的数据显示 一种新的5-HTR调节剂可完全阻止Fmr1基因敲除幼鼠的听源性癫痫发作 具有5-HT1AR和5-HT7R部分激动剂活性。在这里，我们提出了明确的活体行为 药理学和脑电实验与体外受体药理学实验相结合 机械地探测5-羟色胺受体和5-羟色胺7受体，作为可防止听源性癫痫发作的目标(目标1)和 纠正Fmr1基因敲除幼鼠的脑电异常(目标2)。在目标1中，我们假设选择性5-HT1AR激活或选择性5-HT7R失活将减弱听源性癫痫发作并结合5-HT1AR 激活/5-HT7R失活将防止幼年Fmr1基因敲除小鼠的听源性癫痫发作。我们延长了 在目标2中测试这一假设，测试这一药效学效应以纠正脑电表型，例如 纠正幼年Fmr1听觉皮质和体感皮质异常高的伽马频段功率 基因敲除的老鼠。5-HT1AR和5-HT7Rs在海马区密集表达，海马区是一个具有 在Fmr1基因敲除小鼠和患有FXS的个体中改变的低癫痫阈值。在目标3中，选择性 放射性配基将用于饱和结合实验，以评估5-HT1AR和5-HT7R在脑内的表达 [35S]GTPγS测定大鼠脑内5-HT1AR和5-HT7Rs的功能。 幼年Fmr1基因敲除小鼠与野生型小鼠的海马区比较。5-HT1AR和5-HT7Rs配对 以相反的方式调节腺苷环化酶的活性，即5-HT1AR刺激G-αI，而5-HT7Rs 刺激GαS信号。由于已知cAMP在FXS和ASD中会发生变化，因此该项目的结果将 提供关于5-HTR调节cAMP可能影响的关键基础设施的知识 关于翻译有效的FXS和ASD表型。结果还将提供有关以下方面的重要信息 5-HT1AR和/或5-HT7Rs是否为FXS或ASD可行的药物治疗靶点。

项目成果

The Psychedelic N,N-Dipropyltryptamine Prevents Seizures in a Mouse Model of Fragile X Syndrome via a Mechanism that Appears Independent of Serotonin and Sigma1 Receptors.

• DOI: 10.1021/acsptsci.3c00137
• 发表时间: 2023-09
• 期刊: ACS pharmacology & translational science
• 影响因子: 6
• 作者: Richa Tyagi;Tanishka S. Saraf;Clinton E. Canal

FPT, a 2-Aminotetralin, Is a Potent Serotonin 5-HT1A, 5-HT1B, and 5-HT1D Receptor Agonist That Modulates Cortical Electroencephalogram Activity in Adult Fmr1 Knockout Mice.

FPT 是一种 2-Aminotetralin，是一种有效的血清素 5-HT1A、5-HT1B 和 5-HT1D 受体激动剂，可调节成年 Fmr1 敲除小鼠的皮质脑电图活动。

• DOI: 10.1021/acschemneuro.2c00574
• 发表时间: 2022
• 期刊: ACS chemical neuroscience
• 影响因子: 5
• 作者: Saraf,TanishkaS;McGlynn,RyanP;Bhatavdekar,OmkarM;Booth,RaymondG;Canal,ClintonE
• 通讯作者: Canal,ClintonE

Evaluation of lorcaserin as an anticonvulsant in juvenile Fmr1 knockout mice.

• DOI: 10.1016/j.eplepsyres.2021.106677
• 发表时间: 2021-09
• 期刊: Epilepsy research
• 影响因子: 2.2
• 作者: Saraf TS;Felsing DE;Armstrong JL;Booth RG;Canal CE
• 通讯作者: Canal CE