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：
8310090
负责人：
MILLION MULUGETA
金额：
$ 26.24万
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 2014-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8310090
关键词：
Absence of pain sensation Acetylcholine Adrenergic Agents Agonist Behavioral Biological Assay Brain CRF receptor type 1 CRF receptor type 2 Capsaicin Cell Culture Techniques Cell Line 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 Health Homeostasis Hyperalgesia Hypersensitivity Image In Vitro Intestines Irritable Bowel Syndrome Knock-out Knockout Mice 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 receptor response tissue preparation tool urocortin

项目摘要

ABSTRACT 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 stress- or 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. RELEVANCE TO PUBLIC HEALTH 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.

抽象的压力和促肾上腺皮质激素释放因子（CRF）对结肠分泌运动功能产生深远影响，主要通过CRF1受体。 CRF2 在结肠应激反应中的生理作用尚不清楚。初步数据表明，首先，外周 CRF2 的药理学激活可防止 CRF1 介导的应激- 或 CRF 诱导的结肠肠神经元激活和腹泻，而阻断或删除 CRF2 可增强结肠运动对压力的反应。其次，CRF1 激活增强内脏疼痛反应，而 CRF2 激活增强内脏疼痛反应。激活可防止辣椒素诱导的原代培养腰骶部 DRG 神经元 Ca2+ 瞬变。三、CRF 与仅表达 CRF1 的细胞相比，同时表达 CRF1/CRF2 的细胞中 cAMP 的产生量较少。基于这些关键观察结果，我们假设在啮齿类动物中，外周 CRF2 充当压力应对机制通过直接和间接的作用来停止压力引起的结肠运动和内脏痛觉过敏的信号外周靶细胞。具体目标 1 将确立 CRF2 作为压力应对的生理作用通过抑制结肠肠道，急性和慢性应激诱导的结肠运动反应的机制神经元。这将通过阻断或删除 CRF2 以及阻断神经递质来实现途径并通过证明压力和外在神经刺激诱导体内 CRF 配体释放和体外。具体目标 2 将测试 CRF2 阻止 CRF1 介导的乙酰胆碱释放并促进纵向肌间神经丛（LMMP）组织和初级结肠中抑制性神经递质的释放肌间神经元培养。将研究天然细胞和转染细胞中假定的 CRF1-CRF2 相互作用深入了解 CRF1-CRF2 信令串扰。具体目标3将确定是否激活外周 CRF2 通过抑制骨盆传入和通过在体内进行功能、电生理学和分子测定来研究腰骶部 DRG 神经元分离的结肠传入制剂和体外 DRG 神经元。生理作用的阐明和外周 CRF2 抑制应激和 CRF 相关结肠运动改变的机制内脏过敏对于肠易激等功能性疾病具有重要的临床意义综合症，人们越来越认识到压力、CRF1 信号通路和症状之间的联系。与公众健康的相关性拟议的研究旨在确定结肠中的 CRF2 受体信号传导作为压力适应系统维持结肠运动和疼痛反应稳态。该研究与肠道相关由压力引发或加剧的疾病，包括肠易激综合症。效果的阐明和外周 CRF2 激活抑制结肠应激或 CRF 相关增加的机制运动活动和内脏疼痛将对功能性肠道疾病（例如肠易激综合征（IBS）、人们越来越认识到压力和症状之间的联系。