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.

抽象的 压力和皮质激素释放因子（CRF）对结肠秘密运动功能产生深远的影响， 主要通过CRF1受体。 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 - 或CRF诱导的结肠肠神经元激活和腹泻，而CRF2的封锁或缺失增强 结肠运动对压力的反应。其次，CRF1激活增强了内脏疼痛反应，而CRF2 活化可防止辣椒素诱导的原发性培养腰椎DRG神经元Ca2+瞬变。第三，CRF 与仅表达CRF1的细胞相比，在表达CRF1/CRF2的细胞中引起的cAMP产生较少。 基于这些关键观察，我们假设在啮齿动物中，外围CRF2充当应力 信号表明，通过直接和间接的作用停止应力引起的结肠运动和内脏的痛觉过敏 外围靶细胞。特定目标1将确定CRF2作为压力助长的生理作用 急性和慢性应激引起的结肠运动反应的机制，通过抑制结肠肠 神经元。这将通过封锁或删除CRF2以及阻止神经递质来实现 途径并通过证明应力和外在神经刺激在体内诱导CRF配体释放 并在体外。特定目标2将测试CRF2可防止CRF1介导的乙酰胆碱释放并促进 抑制性神经递质在纵向肌肉肌肉丛（LMMP）组织和原发性结肠中释放 肌肉神经元文化。将研究天然和转染细胞中假定的CRF1-CRF2相互作用 对CRF1-CRF2信号交谈的洞察力。具体目标3将确定激活是否激活 外围CRF2通过抑制骨盆传入和 通过在体内进行功能，电生理和分子测定在体内进行功能，电生理和分子测定 分离的结肠传入制剂和体外DRG神经元。阐明生理作用和 外围CRF2会抑制应激和与CRF相关的结肠运动运动的机制，并 内脏超敏反应将对诸如肠易激的功能障碍具有重要的临床意义 综合征，在压力，CRF1信号通路和症状之间存在联系。与公共卫生有关 拟议的研究旨在确定结肠中的CRF2受体信号传导充当应激 适应系统以维持结肠运动和疼痛反应稳态。该研究与肠道有关 包括IBS在内的压力触发或加剧的疾病。阐明影响和 周围CRF2激活湿应力或与CRF相关的机制在结肠中增加 运动活动和内脏疼痛将对功能性肠道疾病（例如IBS）具有重要的临床意义。 为此，压力和症状之间的联系越来越多地认识到。