Morrison Kathleen E, Narasimhan Sneha, Fein Ethan, Bale Tracy L
Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104.
Endocrinology. 2016 May;157(5):2002-14. doi: 10.1210/en.2015-1876. Epub 2016 Mar 4.
The peripubertal period of development is a sensitive window, during which adverse experiences can increase the risk for presentation of cognitive and affective dysfunction throughout the lifespan, especially in women. However, such experiences in the context of a supportive social environment can actually ameliorate this risk, suggesting that resilience can be programmed in early life. Affective disorders and cognitive deficits commonly emerge during aging, with many women reporting increased difficulty with prefrontal cortex (PFC)-dependent executive functions. We have developed a mouse model to examine the interaction between peripubertal experience and age-related changes in cognition and stress regulation. Female mice were exposed to peripubertal chronic stress, during which they were either individually housed or housed with social interaction. One year after this stress experience, mice were examined in tasks to access their cognitive ability and flexibility in stress reactive measures. In a test of spatial memory acquisition and reversal learning where aged females normally display a decreased performance, the females that had experienced stress with social interaction a year earlier showed improved performance in reversal learning, a measure of cognitive flexibility. Because peripuberty is a time of major PFC maturation, we performed transcriptomic and biochemical analysis of the aged PFC, in which long-term changes in microRNA expression and in myelin proteins were found. These data suggest that stress in the context of social support experienced over the pubertal window can promote epigenetic reprogramming in the brain to increase the resilience to age-related cognitive decline in females.
青春期前后的发育阶段是一个敏感窗口,在此期间,不良经历会增加一生中出现认知和情感功能障碍的风险,尤其是在女性中。然而,在支持性社会环境背景下的此类经历实际上可以减轻这种风险,这表明复原力可以在生命早期进行编程。情感障碍和认知缺陷通常在衰老过程中出现,许多女性报告称,依赖前额叶皮质(PFC)的执行功能出现困难的情况增多。我们开发了一种小鼠模型,以研究青春期前后的经历与认知和应激调节方面与年龄相关的变化之间的相互作用。将雌性小鼠暴露于青春期前后的慢性应激环境中,在此期间,它们要么单独饲养,要么在有社交互动的环境中饲养。在这种应激经历一年后,对小鼠进行任务测试,以评估它们的认知能力和应激反应措施的灵活性。在一项空间记忆获取和逆向学习测试中,老年雌性小鼠通常表现出成绩下降,而一年前经历过社交互动应激的雌性小鼠在逆向学习(一种认知灵活性指标)中表现出了更好的成绩。由于青春期前后是PFC主要成熟的时期,我们对老年PFC进行了转录组学和生化分析,发现了微小RNA表达和髓磷脂蛋白的长期变化。这些数据表明,在青春期窗口期间经历的社会支持背景下的应激可以促进大脑中的表观遗传重编程,以增强雌性小鼠对与年龄相关的认知衰退的复原力。