CRF2 Receptor Modulation of Colonic Response to Stress

CRF2 受体调节结肠对压力的反应

• 批准号: 7140419
• 负责人: MILLION MULUGETA
• 金额: $ 18.46万
• 依托单位: UNIVERSITY OF CALIFORNIA LOS ANGELES
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-08-15 至 2008-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7140419
• 关键词: RNA interference; biological signal transduction; colon; corticotropin releasing factor; electrophysiology; gastrointestinal disorder; gastrointestinal motility /pressure; hormone receptor; hormone regulation /control mechanism; immunocytochemistry; irritable bowel syndrome; laboratory rat; laser capture microdissection; neurochemistry; neurohormones; pain; physiologic stressor; polymerase chain reaction; receptor expression; stomach motility /pressure

DESCRIPTION (provided by applicant): Stress exerts a profound effect on the gut and altered stress response is associated with functional disorders, including irritable bowel syndrome (IBS). Brain corticotropin-releasing factor (CRF) and CRF receptor 1 (CRF1) play an important role in the colonic motor, anxiogenic and endocrine responses to stress, while activation of CRF2 restrains the behavioral and endocrine responses to stress. The objectives, based on our preliminary data, are to test in conscious rats the novel concept that peripheral CRF2 impedes the CRF1 receptor-mediated stress- and CRF-induced colonic motility and visceral hyperalgesia as part of a stress-coping mechanism. Specific aim 1 will establish that peripheral activation of CRF2 counteracts the stimulatory effect of CRF and stress on colonic motor function. This will be achieved by: 1) characterizing, in vivo and in vitro, the inhibitory action of peripheral CRF2 agonist, urocortin 2 (Ucn 2) on CRF1 preferential agonist, oCRF1- and stress-induced colonic motor stimulation; and 2) determinining the neuromediators involved in CRF2 action and the chemical coding of cells expressing CRF2 in the colonic tissue. Specific aim 2 will demonstrate that peripheral CRF2 activation blunts colorectal distention (CRD) and stress-induced visceral pain. This will be achieved by: 1) assessing the inhibitory effect of peripheral injection of Ucn 2 against CRD and stress-induced enhanced visceral pain ; and 2) identifying the neuronal and chemical pathways by which Ucn 2 attenuates the visceral pain response to CRD and stress. The mechanisms involved in the CRF2 mediated modulation of visceral pain will be determined by functional (visceral pain to CRD) and electrophysiological (in vitro colonic afferent activation by distention) measurements, as well as induction of Fos and activation of Erk in the lumbo-sacral spinal cord. Novel tools such as RNAi to silence colonic CRF and CRF2 receptor gene, ultrasonomicrometry for in vitro motility measurements and laser capture microdissection techniques to determine tissue distribution of CRF2 and ligands, highly selective CRF receptor and ligand antibodies and CRF2 antagonists will be used in these studies. The elucidation of the effects and mechanisms through which peripheral CRF2 dampen stress- and CRF-related colonic motor alteration and visceral hypersensitivity will have important clinical implications in functional disorders such as IBS, for which a link between stress, CRF signaling pathway and symptoms are increasingly recognized.

描述（由申请人提供）：压力对肠道和改变的应力反应产生深远的影响与功能障碍有关，包括肠易激综合征（IBS）。脑皮质激素释放因子（CRF）和CRF受体1（CRF1）在结肠运动，对压力的焦虑和内分泌反应中起着重要作用，而CRF2的激活限制了行为和内分泌对压力的反应。基于我们的初步数据的目标是在有意识的大鼠中测试外围CRF2的新颖概念，该概念阻碍了CRF1受体介导的应激和CRF诱导的结肠运动性和内脏的超痛性，作为应激培养机制的一部分。具体目标1将确定CRF2的外围激活抵消CRF和应力对结肠运动功能的刺激作用。这将通过：1）在体内和体外表征外周CRF2激动剂的抑制作用，尿皮质素2（UCN 2）对CRF1优先激动剂，OCRF1-和压力诱导的结肠运动刺激； 2）确定参与CRF2作用的神经对象以及在结肠组织中表达CRF2的细胞的化学编码。具体的目标2将表明外围CRF2激活钝性结直肠扩张（CRD）和应力引起的内脏疼痛。这将通过以下方式实现：1）评估UCN 2外周外注射对CRD的抑制作用，以及应激引起的内脏疼痛的增强； 2）识别UCN 2减弱对CRD和压力的内脏疼痛反应的神经元和化学途径。 CRF2介导的内脏疼痛调节涉及的机制将由功能（内脏疼痛到CRD）和电生理学（通过延伸的体外结肠传入激活）以及FOS的诱导和ERK激活在腔体脊髓脊髓中。新的工具，例如RNAi到沉默的结肠CRF和CRF2受体基因，用于体外运动测量的超声学和激光捕获显微解剖技术，以确定CRF2和配体的组织分布，高度选择性的CRF受体受体和配体抗体和CRF2拮抗剂。阐明外围CRF2抑制与CRF相关的结肠运动改变和内脏性超敏反应的作用和机制将对IBS等功能障碍产生重要的临床意义，IBS（例如IBS）越来越多地认识到压力，CRF信号通路和症状之间的联系。