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

• 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
• 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

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.

摘要 应激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CRF 1受体。CRF 2在结肠应激反应中的生理作用尚不清楚。 初步数据显示，首先，外周CRF 2的药理学激活可防止CRF 1介导的应激- 或CRF诱导的结肠肠神经元活化和腹泻，而CRF 2的阻断或缺失增强了 结肠运动对压力的反应第二，CRF 1激活增强内脏疼痛反应，而CRF 2 激活阻止辣椒素诱导的原代培养腰骶DRG神经元Ca 2+瞬变。第三，CRF 导致同时表达CRF 1/CRF 2的细胞比仅表达CRF 1的细胞产生更少的cAMP。 基于这些关键的观察，我们假设在啮齿动物中，外周CRF 2作为一种压力应对机制， 通过直接和间接作用于 外周靶细胞具体目标1将建立CRF 2作为压力应对的生理作用 急性和慢性应激诱导的结肠运动反应的机制，通过抑制结肠肠 神经元这将通过阻断或删除CRF 2以及阻断神经递质来实现 通过证明应激和外源性神经刺激诱导体内CRF配体释放， 和体外。具体目标2将测试CRF 2阻止CRF 1介导的乙酰胆碱释放并促进CRF 1介导的乙酰胆碱释放。 结肠纵行肌间神经丛（LMMP）组织和原代结肠组织中抑制性神经递质释放 肌间神经元培养将研究天然和转染细胞中推定的CRF 1-CRF 2相互作用， 深入了解CRF 1-CRF 2信号串扰。具体目标3将确定是否激活 外周CRF 2通过抑制盆腔传入神经抑制应激诱导的内脏痛敏感化， 腰骶部DRG神经元的功能，电生理和分子测定在体内， 分离的结肠传入制备物和体外DRG神经元。阐明了其生理作用， 外周CRF 2通过其抑制应激和CRF相关结肠炎改变的机制， 内脏高敏感性在功能性疾病如肠易激综合征中具有重要的临床意义 综合征，其中压力，CRF 1信号通路和症状之间的联系越来越多地被认识到。与公共卫生的关系 这项拟议的研究旨在确定结肠中CRF 2受体信号传导作为应激的功能。 适应系统，以维持结肠运动和疼痛反应的稳态。该研究与肠道相关 由压力引发或加剧的疾病，包括IBS。效果的阐明和 外周CRF 2激活抑制应激或CRF相关的结肠炎增加的机制 运动活动和内脏痛对功能性肠道疾病如IBS具有重要的临床意义， 人们越来越认识到压力和症状之间的联系。