Mechanisms of sex selective enhancement of threat anticipation following early life adversity

项目摘要。经历早期生活逆境（ELA），如资源稀缺，与 焦虑相关障碍，包括广泛性焦虑障碍（GAD）。女性比男性多两倍 焦虑症的患病率，症状表现更强烈，对治疗的反应更差。一 广泛性焦虑症的核心特征是对不一定存在的威胁的高度预期。 虽然对威胁的反应是适应性的，但在没有真实的威胁的情况下，过度预期可能表现为 病理检查潜在威胁预期的神经关联对于理解性至关重要- 具体风险和开发有效的治疗方法。ELA改变了威胁响应电路， 中央杏仁核（CeA）的过度招募，这是一个对威胁学习很重要的区域。神经肽， CeA内的促肾上腺皮质激素释放激素（Crh）对威胁预测线索做出反应，并发出长距离的信号。 投射到终纹床核（BNST），这是一个已知的行为调节区域， 对压力的反应。然而，ELA对Crh+ CeA向BNST投射的影响以及性别差异如何影响BNST的表达， 在这一预测可能改变威胁的预期仍然不清楚。因此，检查Crh CeA到BNST 投射作为一个潜在的神经生物学靶点，ELA通过它增强对威胁的反应， 了解病理学的神经基础和风险的性别差异。 惊吓反应是一种特别适合研究威胁反应的内在表型，因为它是 在明确提示威胁时可靠地增强。它还提供了一个有用的翻译工具，因为行为 已广泛用于临床。在初步研究中，我使用ELA的有限卧床小鼠模型， 测试它对惊吓反应的影响，作为威胁预期的指标。我发现经历过ELA的老鼠 在条件音存在和不存在的情况下，对巨大噪音的惊吓增强，这表明 对威胁的高度和不适应的预期。重要的是，这种影响仅限于女性。我 假设威胁预期是由CeACrh对BNST神经元的激活和ELA驱动的 雌性小鼠在威胁存在和不存在时都表现出该回路的过度激活。在目标1中， 当威胁存在或不存在时，将测试Crh CeA与BNST活性的性别和ELA特异性差异 通过使用纤维光度计来可视化来自投射到BNST的CeA Crh神经元群体的钙活性， 在恐惧强化惊吓任务中。在目标2中，我将测试CeA Crh到BNST投影的必要性， 通过在存在威胁的情况下光遗传学地抑制来自CeA的Crh BNST末端来预期威胁。 最终，这些知识可能有助于开发焦虑症的适当治疗方法 根据个人的经验和性别而个性化。我将通过这次F31奖励获得的培训 我将支持我成为一个全面和独立的研究科学家，专注于研究 病理学的动物模型和ELA对情绪发展的后果。

PROJECT SUMMARY. Experiencing early life adversity (ELA), such as resource scarcity, is associated with anxiety-related disorders, including generalized anxiety disorder (GAD). Women have a two-fold greater prevalence of anxiety disorders, more robust presentation of symptoms, and poorer response to treatments. A debilitating and core feature of GAD is heightened anticipation of threat when it is not necessarily present. While responding to threat is adaptive, excessive anticipation in the absence of real threat can manifest as pathology. Examining the neural correlates underlying threat anticipation is critical to understanding sex- specific risk and developing effective treatments. ELA alters threat response circuitry, associated with excessive recruitment of the central amygdala (CeA), a region important for threat learning. A neuropeptide, corticotropin releasing hormone (Crh), within the CeA responds to threat-predictive cues and send long-range projections to the bed nucleus of the stria terminalis (BNST), a region known for behavioral modulation in response to stress. However, the impact of ELA on the Crh+ CeA to BNST projection and how sex-differences within this projection may alter threat anticipation remains unclear. Thus, examining the Crh CeA to BNST projection as a potential neurobiological target by which ELA enhances responses to threat will be central to understanding neural underpinnings of pathology and sex differences in risk. The startle response is an especially suitable endophenotype to study threat responding because it is reliably enhanced when threat is explicitly cued. It also provides a useful translational tool, as the behavior has been widely used in clinical settings. In preliminary studies, I used the limited bedding mouse model of ELA to test its effects on startle response as an index of threat anticipation. I found that mice who experience ELA exhibit enhanced startle to a loud noise both in the presence and absence of the conditioned tone, suggesting both heightened and maladaptive anticipation of threat. Importantly, this effect was exclusive to females. I hypothesize that anticipation of threat is driven by activation of CeACrh to BNST neurons and that ELA female mice show excessive activation of this circuit both when threat is present and absent. In Aim 1, I will test for sex- and ELA-specific differences of Crh CeA to BNST activity when threat is either present or absent by using fiber photometry to visualize calcium activity from a population of CeA Crh neurons projecting to BNST during the fear-potentiated startle task. In Aim 2, I will test the necessity of the CeA Crh to BNST projection for anticipated threat by optogenetically inhibiting Crh BNST terminals from CeA in the presence of threat. Ultimately, this knowledge may contribute to the development of proper treatments for anxiety disorders that are individualized to the experience and sex of the individual. The training I will gain through this F31 award will support my path towards becoming a well-rounded and independent research scientist focused on studying animal models of pathology and the consequences of ELA on emotional development.