Molecular mechanisms regulating seasonal physiology

季节性哺乳动物在一年中经历了巨大的生理变化。它们精确调节新陈代谢、体重和生殖功能，在多变的环境中维持能量平衡。生理上的适应是大脑中基因表达变化的结果，这种变化是由白天长度的变化驱动的，通过褪黑激素，控制着能量平衡和生殖的关键功能。直到最近几年才有研究表明，下丘脑的甲状腺激素（T3）对鸟类和哺乳动物的光周期反应至关重要，但迄今为止，人们对T3触发调节中心重新连接的机制知之甚少。季节性哺乳动物在食物短缺时保持能量平衡的最极端措施是表现出麻木。这种精确控制的低代谢和低体温被认为是由整合到光周期背景中的代谢信号驱动的，但主要的调节机制在很大程度上是未知的。我们的目标是阐明下丘脑中枢通过传递环境和营养信号来控制季节性哺乳动物的代谢、体温和体重的一系列分子机制。了解季节性哺乳动物能量平衡中这些预期的长期变化背后的机制具有重要价值，因为它为确定能量稳态和体重调节的新机制提供了令人兴奋的机会。

Seasonal mammals undergo massive physiological changes over the course of a year. They precisely regulate metabolism, body weight and reproductive functions as appropriate to maintain energy balance in a variable environment. The physiological adaptations are the result of changes in gene expression in the brain that are driven by changes in day length via the hormone melatonin and that control key functions in energy balance and reproduction. Only in recent years has it been shown that thyroid hormone (T3) availability to the hypothalamus is essential for the photoperiodic response of birds and mammals, but to date little is known about the mechanisms T3 may trigger to rewire regulatory centres. The most extreme measure of seasonal mammals to maintain energy balance in times of food shortage is the expression of torpor. This precisely controlled hypometabolism and hypothermia is thought to be driven by metabolic signals that are integrated into a photoperiod background but central regulatory mechanisms are largely unknown. Our goal is to clarify the cascade of molecular mechanisms by which hypothalamic centers relay environmental and nutritional signals to the control of metabolism, body temperature and body weight in seasonal mammals. Understanding the mechanisms underlying these anticipatory long-term changes in energy balance in seasonal mammals is of great value because it offers exciting opportunities to identify novel mechanisms in the regulation of energy homeostasis and body weight.