Role of GABA on circadian and homeostatic regulation of sleep

GABA 对昼夜节律和睡眠稳态调节的作用

• 批准号: 9128731
• 负责人: Horacio O De La Iglesia
• 金额: $ 33.8万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-01 至 2019-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9128731
• 关键词: Absence Epilepsy; Activity Cycles; Address; Adult; Animal Disease Models; Animals; Autistic Disorder; Automobile Driving; Brain; Brain region; Caregivers; Cell Nucleus; Cells; Childhood; Circadian Rhythms; Cognitive deficits; Dependovirus; Disease; Effectiveness; Epilepsy; Exons; Generalized seizures; Generations; Genes; Genetic Recombination; Goals; Grant; Health; Hypothalamic structure; Impairment; Interneurons; Lead; Light; Modeling; Mus; Mutation; Nature; Neurons; Nucleic Acid Regulatory Sequences; Patients; Phase; Phenotype; Physiologic pulse; Process; Quality of life; REM Sleep; Regulation; Research; Rest; Role; SCN1A protein; Seizures; Site; Sleep; Sleep Deprivation; Sleep Disorders; Slow-Wave Sleep; Symptoms; Syndrome; Testing; Thalamic structure; Time; Vasoactive Intestinal Peptide; Viral; Virus; base; circadian pacemaker; conditional mutant; gamma-Aminobutyric Acid; loss of function mutation; mouse model; mutant; neuromechanism; non rapid eye movement; promoter; recombinase; relating to nervous system; response; sleep abnormalities; sleep regulation; sleep regulatory center; suprachiasmatic nucleus; voltage

 DESCRIPTION (provided by applicant): Animals carrying a heterozygous loss-of-function mutation in the Scn1a gene (Scn1a+/- mice), which encodes a subunit of the voltage-gated Na+ channel NaV1.1, show deficits in both homeostatic regulation of sleep and circadian regulation of rest-activity cycles. The NaV1.1 channel is the primary voltage-gated Na+ channel in adult GABAergic interneurons and its reduced activity results in a decrease of GABAergic tone, suggesting that sleep regulatory deficits in Scn1a+/- mice emerge from reduced GABAergic activity. However, Scn1a+/- mice are a model of a severe form of epilepsy known as Dravet syndrome (DS) and, as DS patients, show not only dysregulation of sleep but also generalized seizures. Epileptic activity complicates the interpretation of sleep disorders in DS, as sleep regulatory deficits could be the result of sleep disruption by seizures or of seizure-associated neural damage. Our hypothesis is that sleep disorders in DS are the consequence of reduced GABAergic tone within sleep regulatory centers that is independent of the presence of seizures. To address this hypothesis, we propose to conditionally target the Scn1a+/- mutation to specific neurons and brain regions. Specific Aim 1 will determine whether sleep abnormalities in global Scn1a+/- mice emerge from the effect of the mutation specifically on GABAergic neurons. We will target the Scn1a+/- mutation to these cells using an Scn1alox/- mouse and a Cre driver mouse line that targets GABAergic neurons throughout the brain, and will assess the integrity of the circadian and homeostatic regulation of sleep in these mutants. This approach will unequivocally determine whether sleep regulatory deficits in Scn1a+/- mice are the result of reduced NaV1.1 channel activity within GABAergic cells or whether non- GABAergic cells that express the channel also contribute to this phenotype. Specific Aim 2 will target the Scn1a+/- mutation to cells in the suprachiasmatic nucleus (SCN), the site of the central circadian pacemaker that regulates sleep. Viruses expressing Cre recombinase, targeting either all SCN cells or specifically vasoactive intestinal polypeptide (VIP)-containing cells, will be injected wihin the SCN of Scn1alox/+ mice. We will also target the mutation to the SCN VIPergic cells by crossing Scn1alox/+ mice with a mouse line in which the VIP promoter drives the expression of Cre. Because VIP neurons are essential for the integrity of the SCN oscillatory network, we expect that these VIP-specific Scn1a+/- mutants will show similar effects to mutants in which all SCN cells are targeted. Specific Aim 3 will virally target the Scn1a+/- mutation to the reticular nucleus of the thalamus (RNT), which is essential for the generation of slow-wave sleep and spindles during non- REM sleep, both compromised in Scn1a+/- mice. None of the conditional mutant approaches in Aims 1 and 2 is expected to induce seizures, offering a unique opportunity to assess the effect of reduced NaV1.1 channel activity in sleep regulatory regions, in the absence of seizures. We predict that the conditional targeting of the Scn1a+/- mutation to the SCN and RNT will lead to deficits in circadian and homeostatic regulation of sleep, respectively. These results would provide direct support for the role of the NaV1.1 channel within these brain regions in the regulation of sleep. They would also directly support our hypothesis that both circadian and homeostatic sleep deficits in DS emerge from seizure-independent reduced GABAergic activity in specific brain regions, providing new avenues for the treatment of sleep disorders in DS.

 描述（由申请人提供）：Scn1a 基因携带杂合功能丧失突变的动物（Scn1a+/- 小鼠）（编码电压门控 Na+ 通道 NaV1.1 的一个亚基）在体内稳态调节方面表现出缺陷NaV1.1 通道是成人 GABA 能中间神经元及其中的主要电压门控 Na+ 通道。活性降低导致 GABA 活性降低，这表明 Scn1a+/- 小鼠的睡眠调节缺陷是由 GABA 活性降低引起的。然而，Scn1a+/- 小鼠是一种称为 Dravet 综合征 (DS) 的严重癫痫模型。作为 DS 患者，不仅表现出睡眠调节失调，而且全身性癫痫活动使 DS 睡眠障碍的解释变得复杂，因为睡眠调节缺陷可能是睡眠的结果。我们的假设是，DS 中的睡眠障碍是睡眠调节中心内 GABA 能张力降低的结果，与癫痫发作的存在无关。 Scn1a+/- 特定神经元和大脑区域的突变将确定整体 Scn1a+/- 小鼠的睡眠异常是否因突变对 GABA 能神经元的影响而出现。使用 Scn1alox/- 小鼠和 Cre 驱动小鼠系对这些细胞进行 Scn1a+/- 突变，该小鼠系针对整个大脑的 GABA 能神经元，并将评估这些突变体中睡眠的昼夜节律和稳态调节的完整性。 Scn1a+/- 小鼠的睡眠调节缺陷是 GABA 能细胞内 NaV1.1 通道活性降低的结果，还是表达该通道的非 GABA 能细胞所致Specific Aim 2 将针对视交叉上核 (SCN) 中的细胞进行 Scn1a+/- 突变，该细胞是调节睡眠的中央昼夜节律起搏器的部位，可针对所有 SCN 细胞或特定的血管活性细胞。含有肠多肽（VIP）的细胞将被注射到 Scn1alox/+ 小鼠的 SCN 内，我们还将针对突变。通过将 Scn1alox/+ 小鼠与 VIP 启动子驱动 Cre 表达的小鼠系杂交，将其转化为 SCN VIPergic 细胞，因为 VIP 神经元对于 SCN 振荡网络的完整性至关重要，因此我们预计这些 VIP 特异性 Scn1a+/-突变体将表现出与所有 SCN 细胞都被靶向的突变体相似的效果，Specific Aim 3 将以病毒方式将 Scn1a+/- 突变靶向丘脑的网状核。 (RNT)，这对于非快速眼动睡眠期间慢波睡眠和纺锤体的产生至关重要，两者在 Scn1a+/- 小鼠中均受到损害，预计目标 1 和 2 中的条件突变方法均不会诱发癫痫发作，从而提供了癫痫发作的机会。在没有癫痫发作的情况下，评估睡眠调节区 NaV1.1 通道活性降低的影响是一个独特的机会，我们预测 Scn1a+/- 突变对 SCN 和 RNT 的条件性靶向作用将会发挥作用。分别导致睡眠的昼夜节律和稳态调节缺陷。这些结果将为这些大脑区域内的 NaV1.1 通道在睡眠调节中的作用提供直接支持。它们也将直接支持我们的假设，即昼夜节律和稳态调节。 DS 中的睡眠缺陷是由特定脑区中与癫痫发作无关的 GABA 活性降低引起的，这为 DS 中睡眠障碍的治疗提供了新途径。