Investigating the Role of Metabolic Stress in Major Depressive Disorder

项目摘要 重度抑郁症（MDD）是美国最常见的疾病之一， 在2型糖尿病（T2 DM）患者中加倍。传统上被认为是两个相互作用的， 基本上独立的疾病，新的证据表明，MDD和T2 DM可能有一个共同的 病因：代谢失调。代谢失调可能会破坏关键边缘区域的神经元活动， 为MDD做贡献然而，关于代谢过程如何影响关键神经元活动的知之甚少。 边缘系统区域，如控制状态下的基底外侧杏仁核（BLA），或这些过程如何成为 在代谢应激条件下失调。这项研究的中心假设是AMPK在细胞内发挥作用， 在BLA兴奋性和情感行为中的重要调节作用， 代谢紧张的情况下。本项目将首先阐明AMPK活性如何调节情感行为 对大鼠使用位点特异性注射AMPK灭活剂到BLA中，情感行为将使用 高架十字迷宫和强迫游泳任务范式。运动和认知行为也将进行测试， 旷场迷宫和新物体识别任务。除了药理学AMPK失活，AAV 将病毒注射入BLA，以表达AMPK β 2亚单位的显性阴性形式，特异性地表达AMPK β 2亚单位， BLA主要神经元，测试细胞类型特异性AMPK失活对情感行为的影响。第二、 这个项目将描述AMPK活性如何调节BLA主要神经元的兴奋性。采用全细胞 膜片钳切片电生理学，AMPK灭活剂的细胞内和细胞外给药的作用 对BLA主要神经元的膜电阻、峰电位阈值和LTP阈值进行测试。的影响 显性负性AMPK β 2亚基表达对这些电生理特性的影响也将是 测定了第三，上述实验将重复使用大鼠喂养高果糖饮食，一个良好的- 代谢应激的特征模型。因此，我们将测试高果糖饮食对AMPK活性的影响， 情感行为和血脑屏障电生理学我们还将测试高果糖饮食的影响是否可以 通过施用药理学AMPK激活剂或细胞类型特异性过表达AMPK来拯救。 野生型AMPK β 2。分子电生理和行为技术的结合将帮助我们 了解正常和功能失调状态下代谢状态和情绪调节之间的联系。 阐明AMPK信号级联在BLA中的作用有助于我们理解MDD 病因学和导致新的抗抑郁药的发展。

Project Summary The prevalence of major depressive disorder (MDD), one of the most common disorders in the United States, is doubled in patients with type 2 diabetes mellitus (T2DM). Traditionally thought of as two interacting, though fundamentally independent disorders, emerging evidence suggests that MDD and T2DM may share a common etiology: dysregulated metabolism. Dysregulated metabolism could disrupt neuronal activity in key limbic areas, contributing to MDD. However, little is known about how metabolic processes affect neuronal activity in key limbic areas such as the basolateral amygdala (BLA) in control states, or how these processes become dysregulated under metabolically stressful conditions. The central hypothesis of this study is that AMPK plays an important regulatory role in BLA excitability and affective behavior that becomes dysregulated under metabolically stressful conditions. This project will first elucidate how AMPK activity regulates affective behavior in rats. Using site-specific injection of an AMPK inactivator into the BLA, affective behavior will be tested using the elevated plus maze and forced swim task paradigms. Motor and cognitive behavior will also be tested using the open field maze and novel object recognition task. In addition to pharmacological AMPK inactivation, AAV viruses will be injected into the BLA to express a dominant-negative form of the AMPK 2 subunit specifically in BLA principal neurons, testing the effect of cell-type specific AMPK inactivation on affective behavior. Secondly, this project will characterize how AMPK activity modulates BLA principal neuron excitability. Using whole-cell patch clamp slice electrophysiology, the effect of intra- and extracellular administration of an AMPK inactivator on membrane resistance, spike threshold, and LTP threshold of BLA principal neurons will be tested. The effects of dominant negative AMPK 2 subunit expression on these electrophysiological properties will also be measured. Thirdly, the above experiments will be repeated using rats fed a high-fructose diet, a well- characterized model of metabolic stress. We will thus test the effects of the high fructose diet on AMPK activity, affective behavior, and BLA electrophysiology. We will also test if the effects of a high-fructose diet can be rescued through administration of a pharmacological AMPK activator, or cell type specific overexpression of wild-type AMPK 2. The combination of molecular, electrophysiological, and behavioral techniques will help us understand the link between metabolic state and mood regulation in both normal and dysfunctional states. Elucidating the role of the AMPK signaling cascade in the BLA could contribute to our understanding of MDD etiology and lead to novel antidepressant development.