Interleukin-1: A promoter of slow wave sleep

描述(申请人提供)：许多与失眠有关的症状，如疲劳、表现障碍、代谢综合征、慢性炎症、嗜睡等；可由白介素1β(IL1)或相关细胞因子引起，或可通过阻断它们来预防。然而，IL1家族在大脑中的调控大多还不确定。最近发现了一种新的脑特异性IL1受体辅助蛋白(IL1AcPB)。尽管它的功能尚不清楚，但初步数据显示，睡眠不足增强了它的皮质表达。IL1家族的另一个成员IL36(以前的ILF7)的功能最近才被发现；IL36抑制包括IL1在内的几种促炎睡眠细胞因子的表达，同时促进抗炎抗睡眠细胞因子的表达。在目标1中，我们确定了IL1AcPb和IL36在睡眠调节中的作用。100多年来，人们已经知道，长时间的清醒(W)可以增强大脑的产生和睡眠调节物质(SRSS)的释放。然而，导致SRS活性增强的W的性质仍有待确定。在目标2中，我们调查了一种假设，即在神经传递过程中释放的ATP是提供先前W活动的测量的信号。具体地说，ATP通过嘌呤P2受体，通过从胶质细胞释放细胞因子，如IL1，转化为先前大脑使用的更持久的指数。初步数据表明，三磷酸腺苷激动剂促进睡眠，而三磷酸腺苷拮抗剂抑制睡眠，而P2X7受体的表达随睡眠倾向的不同而变化。在目标2中，我们通过使用缺乏关键模型组件基因(如P2X7受体)的小鼠来测试我们的模型，即ATP-细胞因子-腺苷假说。例如，这些小鼠已经减弱了对睡眠不足和炎性刺激内毒素的睡眠反应。在目标3中，我们重点研究了SRS基因表达的活性依赖性和EEG Delta功率。我们利用光敏通道视紫红质2(ChR2)基因在细胞培养中表达，然后用不同的光模式激活细胞，确定SRS和模型基因的表达。我们还使用ChR2转基因小鼠在体内控制皮质神经元的激活和随后的脑电表现。预期的结果将为炎症如何改变睡眠以及细胞活动如何转化为SRS机制等问题提供机械性答案。研究结果将实际应用于IL1相关的脑病理，包括发生在睡眠呼吸暂停和代谢综合征中的炎症相关睡眠障碍。 公共卫生相关性：研究了白介素1(IL1)及其家族成员(IL1F)在炎症相关睡眠障碍和生理睡眠调节中的作用。脑特异性IL1受体辅助蛋白和IL36参与睡眠和大脑炎症过程的研究已经确定。此外，在神经传递过程中释放的ATP被认为是大脑在清醒时跟踪先前活动的机制的一部分。我们验证了这一假说，即细胞外的ATP通过嘌呤2型受体-介导IL-1和其他细胞因子从胶质细胞释放，并在睡眠调节和睡眠对炎症信号的反应中发挥关键作用。最后，我们测试了不同的细胞激活模式是否改变了三磷酸腺苷-细胞因子-腺苷假说中IL1和其他成分的基因表达，以及不同的细胞激活模式是否差异地改变了脑电三角洲功率状态。研究结果将实际应用于IL1相关的脑病理，包括发生在睡眠呼吸暂停和代谢综合征中的炎症相关睡眠障碍。

DESCRIPTION (provided by applicant): Many of the symptoms associated with sleep loss, e.g. fatigue, performance impairments, metabolic syndrome, chronic inflammation, sleepiness, etc; can be elicited by administration of interleukin-1 beta (IL1) or related cytokines or can be prevented by blocking them. Nevertheless, the regulation of the IL1 family in the brain is mostly undetermined. Recently a new brain-specific IL1 receptor accessory protein (IL1 AcPb) was identified. Although its function remains unknown preliminary data show that sleep deprivation enhances its cortical expression. The function for another IL1 family member, IL36 (formerly ILF7) has very recently (unpublished) been identified; IL36 inhibits several pro-inflammatory somnogenic cytokines including IL1, while simultaneously promoting expression of anti-inflammatory anti-somnogenic cytokines. In Aim 1, we determine the roles that IL1 AcPb and IL36 have in sleep regulation. For over 100 years it has been known that prolonged wakefulness (W) enhances brain production and release of sleep regulatory substances (SRSs). Nevertheless, the property of W that is responsible for enhanced SRS activity remains to be identified. In Aim 2, we investigate the hypothesis that ATP, released during neurotransmission, is a signal that provides a measure of prior W activity. Specifically, ATP is translated, via purine P2 receptors, into a longer lasting index of prior brain usage through release of cytokines such as IL1 from glia. Preliminary data indicate that ATP agonists promote sleep while ATP antagonists inhibit sleep and P2X7 receptor expression varies with sleep propensity. In Aim 2, we test our model, the ATP-cytokine-adenosine hypothesis, by using mice lacking key model component genes such as the P2X7 receptor. These mice, for example have attenuated sleep responses to sleep loss and the inflammatory stimulus, lipopolysaccharide. In Aim 3, we focus on activity-dependency of SRS gene expression and EEG delta power. We make use of the light-sensitive channelrhodopsin 2 (ChR2) gene by expressing it in cell cultures, then activating the cells with various patterns of light and determine SRS and model gene expressions. We also use ChR2- transgenic mice for in vivo controlled activation of cortical neurons and subsequent manifestations on the EEG. Anticipated results will provide mechanistic answers to questions of how inflammation alters sleep and how cellular activity is translated into SRS mechanisms. Results will have practical application to IL1- associated brain pathologies including inflammation-associated sleep disturbances occurring in sleep apnea and metabolic syndrome. PUBLIC HEALTH RELEVANCE: The roles that interleukin-1 (IL1) and IL1 family (IL1F) members have in inflammation-associated sleep disturbances and physiological sleep regulation are investigated. The involvement of a brain-specific IL1 receptor accessory protein and IL36 in sleep and brain-inflammation processes is determined. Further, ATP released during neurotransmission is posited to be part of the mechanism by which the brain tracks prior activity during wakefulness. We test the hypothesis that extracellular ATP, via purine type 2 receptors- mediates release of IL1 and other cytokines from glia and plays a key role sleep regulation and sleep responses to inflammatory signals. Finally, we test whether different patterns of cell activation change gene expression of IL1 and other components of the ATP-cytokine-adenosine hypothesis and whether different cell activation patterns differentially alter EEG delta power state-specifically. Results will have practical application to IL1-associated brain pathologies including inflammation-associated sleep disturbances occurring in sleep apnea and metabolic syndrome.