Modulation of Colonic Response to Stress by Peripheral CRF2 Receptors

外周 CRF2 受体调节结肠对应激的反应

基本信息

批准号：
7899789
负责人：
MILLION MULUGETA
金额：
$ 26.51万
依托单位：
UNIVERSITY OF CALIFORNIA LOS ANGELES
依托单位国家：
美国
项目类别：
财政年份：
2008
资助国家：
美国
起止时间：
2008-08-15 至 2013-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7899789
关键词：
Absence of pain sensation Acetylcholine Acute Adrenergic Agents Agonist Behavioral Biological Assay Brain CRF receptor type 1 CRF receptor type 2 Capsaicin Cell Culture Techniques Cell model Cells Chronic stress Clinical Colon Colorectal Corticotropin-Releasing Hormone Cultured Cells Cyclic AMP Data Diarrhea Disease Endocrine Ensure Enteral Functional disorder G-Protein-Coupled Receptors Genetic Models Habits Homeostasis Hyperalgesia Hypersensitivity Image In Vitro Intestines Irritable Bowel Syndrome Knock-out Lead Ligands Link Mediating Mediator of activation protein Methods Molecular Monitor Motor Motor Activity Mus Muscle Myenteric Plexus Nerve Neurons Neurotransmitters Organism Pain Pathway interactions Pelvis Peptides Peripheral Physiological Play Predisposition Preparation Pressure Transducers Production Rattus Receptor Signaling Regulation Rodent Role Signal Pathway Signal Transduction Spinal Ganglia Stress Stress and Coping Symptoms System Testing Tissues Visceral Visceral pain acute stress adrenergic afferent nerve base biological adaptation to stress cell motility cholinergic coping coping mechanism gastrointestinal in vitro Model in vivo insight neurochemistry neurotransmitter release novel overexpression prevent public health relevance receptor response stressor tissue preparation tool urocortin

项目摘要

DESCRIPTION (provided by applicant): Stress and corticotropin-releasing factor (CRF) exert a profound effect on colon secreto-motor function, primarily through CRF1 receptors. The physiological role of CRF2 in the colonic response to stress is unknown. Preliminary data show that first, pharmacological activation of peripheral CRF2 prevents CRF1-mediated stressor CRF-induced colonic enteric neuron activation and diarrhea while blockade or deletion of CRF2 enhances the colonic motor response to stress. Second, CRF1 activation enhances visceral pain response while CRF2 activation prevents capsaicin induced primary culture lumbosacral DRG neurons Ca2+ transients. Third, CRF causes less cAMP production in cells that express both CRF1/CRF2 than in cells that expresses only CRF1. Based on these key observations, we hypothesize that in rodents, peripheral CRF2 serves as a stress-coping signal that halts stress-induced colonic motility and visceral hyperalgesia through a direct and indirect action on peripheral target cells. Specific aim 1 will establish the physiological role of CRF2 as a stress-coping mechanism in acute and chronic stress-induced colonic motor response, through inhibition of colonic enteric neurons. This will be achieved by blockade or deletion of CRF2 as well as by blocking neurotransmitter pathways and by demonstrating that stress and extrinsic nerve stimulation induce CRF ligand release in vivo and in vitro. Specific aim 2 will test that CRF2 prevents CRF1 mediated acetylcholine release and promotes inhibitory neurotransmitters release in longitudinal muscle myenteric plexus (LMMP) tissue and primary colonic myenteric neuron culture. The putative CRF1-CRF2 interaction in native and transfected cells will be studied to gain insight on the CRF1-CRF2 signaling cross talk. Specific aim 3 will determine whether activation of peripheral CRF2 inhibits stress-induced visceral pain sensitization through the inhibition of pelvic afferents and lumbosacral DRG neurons by performing functional, electrophysiological and molecular assays in vivo in isolated colonic afferent preparation and in vitro DRG neurons. The elucidation of the physiological role and mechanisms through which peripheral CRF2 dampens stress- and CRF-related colonic omotor alterations and visceral hypersensitivity will have important clinical implications in functional disorders such as irritable bowel syndrome, where a link between stress, CRF1 signaling pathway and symptoms are increasingly recognized. Public Health Relevance: The proposed study aims at establishing that CRF2 receptor signaling in the colon functions as a stress adaptation system to maintain colonic motor and pain response homeostasis. The study has relevance to gut diseases that are triggered or exacerbated by stress, including IBS. The elucidation of the effects and mechanisms through which peripheral CRF2 activation dampen stress- or CRF-related increases in colonic motor activity and visceral pain will have important clinical implications for functional gut diseases such as IBS, for which a link between stress and symptoms are increasingly recognized.

描述（由申请人提供）：主要通过CRF1受体对结肠秘密运动功能产生了深远的影响。 CRF2在结肠对胁迫反应中的生理作用尚不清楚。初步数据表明，首先，外周CRF2的药理学激活阻止CRF1介导的应激源CRF诱导的结肠肠神经元激活和腹泻，而CRF2的阻断或缺失可以增强结肠运动对应激的结肠运动反应。其次，CRF1激活增强了内脏疼痛反应，而CRF2激活可防止辣椒素诱导的原发性培养腰s型DRG神经元Ca2+瞬变。第三，与仅表达CRF1的细胞相比，CRF导致表达CRF1/CRF2的细胞的cAMP产生较少。基于这些主要观察结果，我们假设在啮齿动物中，外围CRF2用作应激信号，该信号通过对外围靶细胞的直接和间接作用阻止应力诱导的结肠运动和内脏性痛觉过敏。特定的目标1通过抑制结肠肠神经元，将CRF2作为急性和慢性应激诱导的结肠运动反应的应激机制的生理作用。这将通过阻断或删除CRF2以及通过阻断神经递质途径来实现这一目标，并证明应激和外在神经刺激会在体内和体外诱导CRF配体释放。特定的目标2将测试CRF2可防止CRF1介导的乙酰胆碱释放，并促进纵向肌肉肌肉丛中（LMSP）组织和原发性结肠肌元神经元培养的抑制性神经递质释放。将研究天然和转染细胞中的假定CRF1-CRF2相互作用，以了解CRF1-CRF2信号传输交叉讲座。具体目标3将通过在分离的结肠连续的制剂中，通过在体内进行功能，电生理学和分子分析，通过抑制骨盆传入和腰椎DRG神经元的抑制，是否通过抑制骨盆传入和腰椎DRG神经元来抑制应激诱导的内脏疼痛致敏的激活。阐明外周CRF2通过这种生理作用和机制抑制了与CRF相关的结肠运动运动的改变以及内脏性超敏反应将在功能障碍中具有重要的临床意义，例如肠易激综合征，例如，在压力，CRF1信号通路和症状之间存在联系之间的联系。公共卫生相关性：拟议的研究旨在确定结肠中的CRF2受体信号传导是维持结肠运动和疼痛反应稳态的压力适应系统。该研究与包括IBS在内的压力触发或加剧的肠道疾病有关。阐明周围CRF2激活障碍应激或CRF相关的作用和机制在结肠运动活动和内脏疼痛中增加的症状会增加对功能性肠道疾病（例如IBS）的重要临床意义，而IBS（例如，越来越多地识别压力和症状之间的联系）。