Circadian and homeostatic contributions to physiology cognition and genome-wide expression in human and mouse variants of the PER3 VNTR polymorphism

我们的睡眠-觉醒周期是由两个时钟调节的：一个是生物钟，它的稳定周期接近24小时；另一个是睡眠平衡器，它记录我们睡眠和清醒的时间。正是这两个生物钟之间的相互作用决定了我们在任何时候是否感到困倦。这些生物钟的个体差异及其相互作用也决定了我们的睡眠时间是长还是短，是早起型还是晚睡型，以及我们是否对睡眠不足对表现的影响非常敏感。生理和分子机制，以及这些睡眠-觉醒调节个体差异的遗传基础，还不是很清楚，但对“时钟”基因的研究为揭示这些机制提供了真正的潜力。作为时钟基因之一的牙周病基因，在人体中以一种较长和一种较短的形式存在。这种变化与你是早起型还是晚睡型有关。我们还表明，这种差异会影响我们有多少深度睡眠，以及我们在没有睡眠的夜晚表现如何。它不会影响生物钟的时间。数据表明，这种多态性主要通过影响睡眠稳态器而不是生物钟来影响我们的睡眠-觉醒周期特征。在本研究中，我们将验证perio3的变化影响睡眠稳态器而不是生物钟的假设，并探讨其影响睡眠和认知特征的潜在分子机制。这项研究将在人类和老鼠身上进行。我们将研究携带较长和较短基因不同组合的人类，以及用两种人类变体代替其原生周期表3基因的小鼠。为了描述perio3的差异对生物钟或睡眠稳态器的影响，睡眠-觉醒周期将与生物钟不同步。这将通过强迫睡眠-觉醒周期超过24小时来实现。生物钟跟不上这么长的周期。在这种情况下，我们已经分离了生物钟和睡眠稳态器的生物效应，现在我们可以测试具体的预测，即牙周病基因影响睡眠和认知表现的稳态调节。我们将通过频繁测量睡眠和表现以及大量的生理变量来做到这一点。我们还将收集人类的血液样本和小鼠的组织样本。这些样本将用于评估人类和小鼠组织中bbbb41,000个独特基因和替代转录本的昼夜节律变化，以及由PERIOD3基因编码的蛋白质的昼夜节律变化。将比较携带不同基因变体的个体之间的perio3蛋白节律和基因表达节律。这可能为基因变异发挥其作用的分子机制提供见解。来自人类和小鼠的组织样本也将被用于在这些样本的细胞培养物的分子水平上研究生物钟的周期。这些分子周期将与从整个生物体的行为和激素节律中测量的时钟周期进行比较，试图发现周期表3的变化是否会影响这种关系。拟议的研究将由一个多学科团队进行，该团队拥有睡眠和昼夜生理学、认知心理学以及分子和系统生物学方面的专业知识。这将有助于我们理解睡眠持续时间和时间的日常调节、认知表现及其在睡眠不足后的恶化的基本机制。这一基本知识可能最终应用于许多高度流行的睡眠-觉醒周期紊乱的治疗发展。

Our sleep-wake cycles are regulated by two clocks / the circadian clock, which has a stable period near 24 h, and a sleep homeostat, which keeps track of how long we have been asleep and awake. It is the interaction between these two clocks that determines whether, at any given time, we feel sleepy or not. Individual variation in these clocks and their interaction also determines whether we are a long or short sleeper, a morning or evening type and whether or not we are very sensitive to the effects of sleep loss on performance. The physiological and molecular mechanisms, as well as the genetic basis for these individual differences in sleep-wake regulation, are not very well known, but the study of 'clock' genes offers real potential for uncovering these mechanisms. PERIOD3, which is one of the clock genes, exists in one longer and one shorter form in humans. This variation is associated with whether you are a morning or evening type. We also showed that this difference has an influence on how much deep sleep we have and how we perform during a night without sleep. It does not affect the timing of the circadian clock. The data suggest that this polymorphism has an influence on the characteristics of our sleep-wake cycles primarily by affecting the sleep homeostat rather than the circadian clock. In the proposed research, we will test the hypothesis that the variation in PERIOD3 influences the sleep homeostat rather than the circadian clock, and also investigate the potential molecular mechanisms by which it affects the characteristics of the sleep and cognition. The research will be conducted in humans and mice. We will study humans carrying different combinations of the longer and the shorter version of the gene, and mice in which their native Period3 gene has been replaced with the two human variants. To characterise the impact of differences in PERIOD3 on either the circadian clock or the sleep homeostat, the sleep-wake cycle will be desynchronised from the circadian clock. This will be accomplished by forcing the sleep-wake cycle to a period much longer than 24 h. The circadian clock cannot keep up with such a long period. Under these circumstances we have separated the biological effects of the circadian clock and the sleep homeostat and we can now test the specific predictions that the PERIOD3 gene affects the homeostatic regulation of sleep and cognitive performance. We will do this by frequent measurements of sleep and performance and a large number of physiological variables. We will also collect blood samples from humans and tissue samples from mice. These samples will be used to assess the circadian variation in expression of >41,000 unique genes and alternative transcripts from human and mouse tissues as well as the circadian variation in the protein encoded by the PERIOD3 gene. The PERIOD3 protein rhythm and the gene expression rhythms will be compared between individuals carrying different variants of the gene. This may provide insights into the molecular mechanism by which the variation of the gene exerts its effects. Tissue samples from humans and mice will also be used to study the period of the circadian clock at the molecular level in cell cultures of these samples. These molecular periods will be compared the period of the clock as measured from the behaviour and hormonal rhythms in the whole organism in an attempt to discover whether variation in PERIOD3 affects this relationship. The proposed research will be conducted by a multidisciplinary team with expertise in sleep and circadian physiology, cognitive psychology, as well as molecular and systems biology. It will contribute to our understanding of the basic mechanisms underlying the daily regulation of sleep duration and timing, cognitive performance and its worsening following sleep loss. This basic knowledge may ultimately be applied to the development of treatments of the many and highly prevalent disorders of sleep-wake cycles.