Brain Mechanisms Mediating Genetic Risk For Anxiety and Depression

描述（由申请人提供）：焦虑气质（AT）是儿童时期焦虑和抑郁发展的关键危险因素。人类和猴子的AT在生命早期是可识别的，在整个发育过程中是稳定的，并且是可遗传的。患有极端AT的儿童通常符合社交焦虑障碍的诊断标准，这表明极端气质焦虑和传统上被认为是精神病理学之间的界限模糊。阐明极端AT的分子机制对于改变焦虑和抑郁障碍的发展至关重要。我们验证了灵长类动物的AT模型，它与儿童AT非常相似。证据支持这种发育中的恒河猴模型是建立病理性儿童焦虑机制的最佳模型。灵长类动物模型可以进行机械性的假设检验，这在人类身上是无法进行的。此外，灵长类动物模型很容易翻译，因为它使用了与人类研究相同的成像、行为和内分泌测量方法。我们之前在大量幼年猕猴样本中进行的病变和影像学研究确定了介导AT的神经回路中的3个关键节点：杏仁核中央核（Ce）、海马前部（aHip）和眶额皮质（OFC）。我们的数据表明，OFC在AT改变的Ce和aHip代谢中具有调节作用。利用来自Ce区域的组织预测AT，我们初步的微阵列工作鉴定了转录本，其表达水平预测AT及其潜在的Ce活性。一些更令人兴奋的发现暗示神经可塑性基因表达的改变与AT有关，支持了AT与早期神经发育过程改变有关的假设。拟议的工作将大大扩展这一研究领域。我们将把Ce、aHip和OFC神经元的功能引导激光捕获显微解剖（LCM）与RNA测序（RNAseq）和行为/神经成像技术（代谢活性和功能连接）结合起来。这将使我们能够表征AT及其神经基质基础区域的分子神经元机制。通过使用OFC病变永久性地减少AT及其神经基质的活性，我们将描述OFC对与AT及其长期维持相关的神经元群体中Ce/aHip基因调控的“自上而下”影响。最后，我们将使用RNAseq来评估使用血液中测量的转录本作为AT及其相关改变的神经底物的外周生物标志物的效用。健康/NIMH任务相关性：儿童AT具有显著的焦虑和抑郁发展风险。这些疾病与大量发病率、死亡率和社会经济负担有关。拟议研究的数据将大大增加我们对AT及其神经基质的表达和“自上而下”调控的分子机制的理解。从改变的大脑区域内的神经元中进行深度RNA测序，将为介导和调节儿童AT的神经回路的遗传调控提供详细和全面的观点。这些研究不能在人类身上进行，但可以在年轻的灵长类动物身上完成，并将有助于确定旨在改善生命早期焦虑和抑郁的干预措施的新目标。

DESCRIPTION (provided by applicant): Anxious temperament (AT) is a critical childhood risk factor for the development of anxiety and depression. Human and monkey AT is identifiable early in life, stable across development, and heritable. Children with extreme AT often meet diagnostic criteria for social anxiety disorder, demonstrating the blurred boundary between extreme temperamental anxiety and what is traditionally considered psychopathology. Elucidating the molecular mechanisms underlying extreme AT is essential for efforts aimed at altering the development of anxiety and depressive disorders. We validated a primate model of AT that is remarkably similar to childhood AT. Evidence supports this developmental rhesus monkey model as being the optimal model for establishing mechanisms underlying pathological childhood anxiety. The primate model enables mechanistic hypothesis testing that cannot be performed in humans. Furthermore, the primate model is readily translatable as it uses the same imaging, behavioral, and endocrine measures routinely used in human research. Our prior lesion and imaging studies in a large sample of juvenile macaques identified 3 key nodes in the neural circuit mediating AT: the central nucleus of the amygdala (Ce), anterior hippocampus (aHip), and orbitofrontal cortex (OFC). Our data demonstrates that the OFC has a regulatory role in relation to AT's altered Ce and aHip metabolism. Using tissue from the Ce region predictive of AT, our preliminary microarray work identified transcripts whose expression levels predicted AT and its underlying Ce activity. Some of the more exciting findings implicate alterations in the expression of neuroplasticity genes to be associated with AT, supporting a hypothesis that AT is associated with altered early neurodevelopmental processes. The proposed work will significantly extend this line of research. We will combine functionally- guided laser capture microdissection (LCM) of Ce, aHip, and OFC neurons with both RNA sequencing (RNAseq) and behavioral/neuroimaging techniques (metabolic activity and functional connectivity). This will allow us to characterize molecular neuronal mechanisms in the regions that underlie AT and its neural substrate. By using OFC lesions to permanently reduce AT and activity in its neural substrate, we will characterize the "top-down" influences of OFC on the regulation of Ce/aHip genes in neuronal populations relevant to AT and its long-term maintenance. Finally, we will use RNAseq to assess the utility of using transcripts measured in blood as peripheral biomarkers of AT and its associated altered neural substrate. HEALTH/NIMH MISSION RELEVANCE: Childhood AT confers marked risk for the development of anxiety and depression. These disorders are associated with substantial morbidity, mortality, and socioeconomic burdens. Data from the proposed studies should substantially increase our understanding of the molecular mechanisms underlying the expression and "top-down" regulation of AT and its neural substrate. Deep RNA sequencing in neurons from within the altered brain regions underlying AT will provide a detailed and comprehensive view of the genetic regulation of the neural circuitry that mediates and regulates childhood AT. These studies cannot be performed in humans but can be accomplished in young primates and will facilitate the identification of novel targets for interventions aimed at ameliorating anxiety and depression early in life.