Characterization of Meis1 mutant mice and implications in restless legs syndrome and other sleep disorders

不宁腿综合征（RLS）是一种与睡眠相关的感觉运动神经疾病， 一般人口。RLS的特征性症状包括患者经常移动腿的冲动 伴随着腿部的不舒服的感觉，或者感觉是由腿部的不舒服的感觉引起的。RLS的病理生理学是 不清楚RLS患者的全基因组关联研究（GWAS）已经确定了多达19个基因座， 参与RLS。最重要的关联是在MEIS1基因内。GWAS还将MEIS 1与 失眠，这可能是由RLS引起的。此外，MEIS 1被发现与加速度计导出的 睡眠特征，包括睡眠时间，效率和时间。MEIS1编码一种同源框蛋白， 转录因子。与RLS风险相关的MEIS 1内含子单倍型与蛋白质减少相关 表达，表明该变体导致单倍不足。因此，杂合子Meis1敲除（Meis1 KO）小鼠可用作人类RLS和其他睡眠障碍的潜在模型。我们已经测试了 Meis1 KO小鼠的睡眠和其他RLS样表型。我们的初步数据显示，Meis1 KO 小鼠是过度活跃的，并且具有增加的醒来的可能性，特别是在休息阶段。此外，本发明还提供了一种方法， Meis 1 KO小鼠纹状体DA转换增加，纹状体酪氨酸羟化酶降低，异常放电 纹状体胆碱能中间神经元。多巴胺能和纹状体胆碱能系统都被证明是 参与睡眠调节。然而，他们参与RLS和睡眠的潜在机制是 目前仍不清楚.我们研究的广泛的长期目标是使用Meis 1 KO小鼠来了解 RLS的病理生理学，失眠和其他睡眠障碍，因此开发新的实验 治疗这些疾病的药物。这个应用程序的具体目标是确定 纹状体多巴胺能和胆碱能系统与RLS样表型和睡眠调节的关系，我们 假设多巴胺能和胆碱能系统的变化是Meis 1的细胞自主效应 它们对RLS样表型和睡眠调节的贡献不同。我们计划测试 我们的假设有以下具体目标：1。为了验证多巴胺能系统 有助于RLS和睡眠调节，我们将创建多巴胺能神经元特异性Meis 1 KO小鼠， 进行全面的行为、生化、解剖和电生理测试。2.测试 假设纹状体胆碱能系统有助于RLS和睡眠调节，我们将创建 胆碱能神经元特异性Meis1 KO小鼠，并进行目标1中概述的综合测试。成功 上述目标的完成将确定MEIS 1单倍不足如何影响多巴胺能神经元。 多巴胺受体激动剂可用于治疗RLS。此外，这项研究还有助于改善 目前对RLS和其他睡眠障碍（包括失眠）的病理生理学的理解。的 结果可能有助于开发新的治疗方法和更好的患者治疗策略。

Restless leg syndrome (RLS) is a sleep-related sensorimotor neurological disease affecting up to 10% of the general population. Characteristic symptoms of RLS include an urge for patients to move their legs often accompanied by, or felt to be caused by, uncomfortable sensations in the legs. The pathophysiology of RLS is unclear. Genome-wide association studies (GWAS) of RLS patients have identified up to 19 loci that are involved in RLS. The most significant association is within the MEIS1 gene. GWAS has also linked MEIS1 with insomnia, which can be caused by RLS. Besides, MEIS1 is found to be associated with accelerometer-derived sleep traits, including sleep duration, efficiency, and timing. MEIS1 codes for a homeobox protein thought to be a transcriptional factor. A MEIS1 intronic haplotype linked to RLS risk is associated with decreased protein expression, suggesting the variant causes haploinsufficiency. Therefore, heterozygous Meis1 knockout (Meis1 KO) mice can be used as a potential model for human RLS and other sleep disorders. We have tested the Meis1 KO mice for sleep and other RLS-like phenotypes. Our strong preliminary data showed that Meis1 KO mice were hyperactive and had an increased probability of waking especially during the rest phase. In addition, Meis1 KO mice had increased striatal DA turnover, decreased striatal tyrosine hydroxylase and abnormal firing of striatal cholinergic interneurons. Both dopaminergic and striatal cholinergic systems have been shown to be involved in sleep regulation. However, the underlying mechanisms of their involvement in RLS and sleep are still unclear. The broad, long-term objective of our research is to use the Meis1 KO mice to understand the pathophysiology of RLS, insomnia and other sleep disorders, and therefore to develop novel experimental therapeutics to treat these diseases. The specific goal of this application is to determine the contribution of the striatal dopaminergic and cholinergic systems to RLS-like phenotypes and sleep regulation, We hypothesize that the changes in dopaminergic and cholinergic systems are cell-autonomous effects of Meis1 haploinsufficiency and they contribute differently to RLS-like phenotypes and sleep regulation. We plan to test our hypothesis with the following Specific Aims: 1. To test the hypothesis that the dopaminergic system contributes to RLS and sleep regulation, we will create dopaminergic neuron-specific Meis1 KO mice and perform comprehensive behavioral, biochemical, anatomical, and electrophysiological tests. 2. To test the hypothesis that the striatal cholinergic system contributes to RLS and sleep regulation, we will create cholinergic neuron-specific Meis1 KO mice and perform comprehensive tests outlined in Aim 1. The successful completion of the above Aims will determine how MEIS1 haploinsufficiency influences the dopaminergic system and why dopamine agonists can be used to treat RLS. In addition, the study can help improve the current understanding of the pathophysiology of RLS and other sleep disorders, including insomnia. The results can potentially aid in the development of novel therapeutics and better treatment strategies for patients.