Central Molecular Mechanisms of Stress-Induced Visceral Hypersensitivity

描述（由申请人提供）：肠易激综合征（IBS）是一种慢性功能性胃肠道（GI）疾病，其标志性症状是严重腹痛，与排便习惯改变相关，无任何可识别的疾病。虽然IBS的原因尚不清楚，但临床证据表明腹痛与压力和焦虑之间存在关系，这表明这些患者大脑对GI信号的处理发生了变化。使用临床前模型，我们先前已经证明杏仁核（调节压力和焦虑的大脑区域，并且已经在临床研究中鉴定）的激活可以诱导大鼠的焦虑和GI疼痛/超敏反应。此外，在这种具有IBS样神经病学的动物模型中，我们证明了用药物治疗啮齿动物可以防止应激激素的作用逆转焦虑和疼痛。虽然我们已经对大脑如何在这个模型中调节超敏反应有了一些了解，但仍然未知的是“杏仁核中的哪些基因调节焦虑和胃肠道疼痛？“为了解决这个问题，这个项目将使用两个具体的目标：1）调查如何应激激素表达在杏仁核的变化在动物诱导焦虑和胃肠道过敏。在这个目标中，我们将在两个互补的动物模型中监测基因和蛋白质的表达，以确定哪些基因负责IBS样症状。2)确定是否阻断杏仁核中应激激素的变化可以防止焦虑和胃肠道疼痛的发展。在这一目标中，通过在杏仁核水平上阻止我们模型中基因表达的增加，我们将为GI超敏反应和焦虑的共同调节中的核心作用提供额外的证据。为了实现这些具体目标，导师Greenwood-Van Meerveld博士组建了一个由经验丰富的合作者组成的团队，为学员Anthony C。约翰逊，与必要的工具，以执行必要的分子技术，以监测总（定量反向聚合酶链反应，蛋白质印迹）和局部（原位杂交，免疫组织化学）基因和蛋白质表达。这些分子技术将补充她在IBS样动物模型中提供的焦虑和疼痛行为测量的培训。本项目中所提出的实验的成功完成将为应激诱导的结肠超敏反应的分子机制提供额外的证据，为IBS的治疗提供新的治疗靶点。 公共卫生相关性：成功完成本申请中提出的目标将为杏仁核在大鼠结肠超敏反应发展中的作用提供证据，并将为中枢致敏的分子机制提供新的见解，中枢致敏可能导致肠易激综合征患者人群的慢性过敏。更重要的是，我们的研究结果可以为针对内脏疼痛的新疗法确定新的靶点，以改善治疗，甚至降低肠易激综合征的发展风险。

DESCRIPTION (provided by applicant): The hallmark symptom of irritable bowel syndrome (IBS), a chronic functional gastrointestinal (GI) disorder, is severe abdominal pain, associated with altered bowel habits, in the absence of any identifiable disease. While the cause of IBS is unknown, clinical evidence suggests a relationship between abdominal pain and stress and anxiety, suggesting a change in the brain's processing of GI signals in these patients. Using pre- clinical models, we have previously demonstrated that activation of the amygdala, an area of the brain that regulates stress and anxiety and has been identified in clinical studies, can induce anxiety and GI pain/hypersensitivity in the rat. Additionally in this animal model with IBS-like symptomatology, we then demonstrated that treating the rodents with drugs that prevented the effects of stress hormones reversed the anxiety and pain. While we have gained some insights into how the brain regulates hypersensitivity in this model, what remains unknown is "Which genes in the amygdala regulate anxiety and GI pain?" To address this question, this project will use two specific aims: 1) Investigate how stress hormone expression in the amygdala changes in an animal with induced-anxiety and GI hypersensitivity. In this aim, we will monitor both gene and protein expression in two complementary animal models, to determine which genes are responsible for the IBS-like symptoms. 2) Determine if blocking the changes in stress hormones in the amygdala prevents the development of anxiety and GI pain. In this aim, by preventing the increased gene expression in our models at the level of the amygdala, we will provide additional evidence for a central role in the co-regulation of GI hypersensitivity and anxiety. To achieve these specific aims, the mentor, Dr. Greenwood-Van Meerveld, has assembled a team of experienced collaborators to provide the trainee, Mr. Anthony C. Johnson, with the necessary tools to perform the molecular techniques necessary to monitor both total (quantitative reverse polymerase chain reaction, western blotting) and localized (in situ hybridization, immunohistochemistry) gene and protein expression. These molecular techniques will complement the training that she has provided on the behavioral measurements of anxiety and pain in IBS-like animal models. Successful completion of the experiments proposed in this project will provide additional evidence for the molecular mechanisms of stress-induced colonic hypersensitivity, providing new therapeutic targets for the treatment of IBS. PUBLIC HEALTH RELEVANCE: Successful completion of the aims proposed within this application will provide evidence for the role of the amygdala in the development of colonic hypersensitivity in rats and will offer new insights into the molecular mechanisms of central sensitization that likely lead to chronic symptomatology in the irritable bowel syndrome patient population. More importantly, our findings may identify novel targets for new therapies directed at visceral pain to improve the treatment or even reduce the risk for the development of irritable bowel syndrome.