Glucocorticoid Receptor Mechanisms of Traumatic Stress Pathology

创伤后应激障碍的发病率是退伍军人管理局的一个主要问题，影响了大约13%的人 在OIF或OEF服役。女性似乎比男性更容易患上创伤后应激障碍， 在性侵犯的背景下发生（可能发生在服兵役期间）。一线治疗方案 可以改善症状，但目前还不能治愈。为实现这一目标制定进一步的战略， 了解疾病发展过程的基础该提案旨在测试 假设荷尔蒙对压力和创伤的反应是驱动易感性的关键， 与PTSD相关的行为病理学的发展。在人类中，创伤后应激障碍与对 糖皮质激素信号，由于增强的糖皮质激素受体（GR）信号（由于增加的糖皮质激素 受体表达和/或其抑制性结合配偶体FKBP 5的表达降低）。GR和 FKBP 5基因变异与PTSD的发病率或严重程度有关，表明其作为性状变量影响 疾病发展或进展。PTSD相关的GR和HPA轴功能障碍在啮齿动物中模拟 模型，表明它们有助于与创伤相关的病理行为。病理 这种机制被认为是由前额叶皮层-杏仁核连接的中断所驱动的， 恐惧、焦虑和情感记忆的表达，这些过程反过来又受到压力的调节 荷尔蒙这一提议验证了创伤后糖皮质激素信号干扰前额叶的假设， （边缘下）皮层和杏仁核回路负责恐惧调节，导致持续的递减， 神经回路功能和行为。在这里，我们采用药理学，遗传学和生理学的方法， 了解糖皮质激素控制神经回路机制驱动创伤后病理，使用良好的- 特征化的和可再现的啮齿动物单次长期应激（SPS）模型，以模拟 创伤后应激障碍目的1使用药理学方法阻断或放大边缘下皮质糖皮质激素信号 在SPS之后，测试改变的糖皮质激素受体结合对产生 焦虑相关行为增强，社交退缩，恐惧记忆消退受损， 决策。新的机器学习方法被用来模拟行为缺陷的星座 在SPS之后，并确定阻断或放大边缘下GR信号传导如何改变病理 模型目的2使用最近开发的条件性大鼠GR缺失模型来测试 边缘下GR信号在介导应激病理中的作用，包括直接询问GR在整个神经系统中的作用。 下边缘-基底外侧杏仁核连接。目的3解决SPS后GR信号传导的可能机制 在破坏边缘下-杏仁核回路功能中，采用电生理学方法来测试 GR信号在导致前额兴奋性长期病理性降低中的作用。总的来说，这些数据 预期将确定GR结合在产生与PTSD相关的神经回路病理中的作用， 评估新的或现有的GR调节剂作为假定疾病治疗的效用的跳板 或预防。

Incidence of post-traumatic stress disorder is a major problem for the VA, affecting roughly 13% of individuals serving in OIF or OEF. Women appear to be more susceptible to development of PTSD than men, often occurring in the context of sexual assault (which can occur during military service). Frontline treatment options can improve symptoms but do not currently offer a cure. To develop further strategies to this end, it is critical to understand the foundations of the disease process as it develops. The proposal is designed to test the hypothesis that hormonal responsiveness to stress and trauma are critical for driving susceptibility to development of behavior pathologies relevant to PTSD. In humans, PTSD is linked to heightened sensitivity to glucocorticoid signals, due to enhanced glucocorticoid receptor (GR) signaling (due to increased glucocorticoid receptor expression and/or decreased expression of its inhibitory binding partner FKBP5). Both GR and FKBP5 gene variants are linked to PTSD incidence or severity, indicating of a role as trait variable influencing disease development or progression. PTSD-related GR and HPA axis dysfunction are emulated in rodent models, suggesting that they contribute to pathological behaviors associated with trauma. Pathological mechanisms are thought to be driven by disruption of prefrontal cortex-amygdala connections controlling expression of fear, anxiety and emotional memory, processes that are in turn subject to regulation by stress hormones. This proposal tests the hypothesis that post-trauma glucocorticoid signaling disrupts prefrontal (infralimbic) cortex and amygdala circuitry responsible for fear regulation, causing lasting decrements in neurocircuit function and behavior. Here we employ pharmacological, genetic and physiological approaches to understand glucocorticoid control of neurocircuit mechanisms driving posttraumatic pathologies, using a well- characterized and reproducible rodent single prolonged stress (SPS) model to emulate core symptoms of PTSD. Aim 1 uses pharmacological approach to either block or amplify infralimbic cortex glucocorticoid signals in the aftermath of SPS, testing the impact of altered glucocorticoid receptor binding on generation of enhanced anxiety related behaviors, social withdrawal, impaired extinction of fear memories and impaired decision making. Novel machine learning approaches are used to model the constellation of behavioral deficits following SPS and determine how blocking or amplifying infralimbic GR signaling modifies the pathology model. Aim 2 uses a recently-developed conditional rat GR deletion model to test the specific role of the infralimbic GR signaling in mediating stress pathologies, including direct query of GR action across the infralimbic-basolateral amygdala connection. Aim 3 addresses possible mechanisms of post-SPS GR signaling in disruption of infralimbic-amygdala circuit function, employing electrophysiological approaches to test the role of GR signaling in causing long-term pathological reductions in prefrontal excitability. Overall, these data are expected to define the role GR binding in generation of neurocircuit pathology related to PTSD, providing a springboard for evaluating the utility of new or existing GR modulating agents as a putative disease treatment or prevention.