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: 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
• 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

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）：应激和促肾上腺皮质激素释放因子（CRF）主要通过CRF 1受体对结肠分泌-运动功能产生深远影响。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的药理学激活防止CRF 1介导的应激源CRF诱导的结肠肠神经元激活和腹泻，而CRF 2的阻断或缺失增强结肠对应激的运动反应。第二，CRF 1激活增强内脏痛反应，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在同时表达CRF 1/CRF 2的细胞中比在仅表达CRF 1的细胞中引起更少的cAMP产生。基于这些关键观察结果，我们假设在啮齿动物中，外周CRF 2作为应激应对信号，通过对外周靶细胞的直接和间接作用来停止应激诱导的结肠运动和内脏痛觉过敏。具体目标1将通过抑制结肠肠神经元，确立CRF 2作为急性和慢性应激诱导的结肠运动反应中的应激应对机制的生理作用。这将通过CRF 2的阻断或缺失以及通过阻断神经递质通路以及通过证明应激和外源性神经刺激诱导体内和体外CRF配体释放来实现。具体目标2将测试CRF 2防止CRF 1介导的乙酰胆碱释放并促进纵向肌肉肌间神经丛（LMMP）组织和原代结肠肌间神经元培养物中的抑制性神经递质释放。将研究天然和转染细胞中推定的CRF 1-CRF 2相互作用，以深入了解CRF 1-CRF 2信号转导串扰。具体目标3将通过在分离的结肠传入制备物和体外DRG神经元中进行体内功能、电生理学和分子测定，确定外周CRF 2的激活是否通过抑制盆腔传入和腰骶DRG神经元来抑制应激诱导的内脏疼痛敏化。阐明外周CRF 2抑制应激和CRF相关的结肠炎性改变和内脏高敏感性的生理作用和机制将对功能性疾病如肠易激综合征具有重要的临床意义，其中应激、CRF 1信号通路和症状之间的联系越来越被认识。 公共卫生相关性：这项研究旨在确定CRF 2受体信号在结肠中作为一种应激适应系统发挥作用，以维持结肠运动和疼痛反应的稳态。这项研究与由压力引发或加剧的肠道疾病有关，包括IBS。阐明外周CRF 2激活抑制应激或CRF相关的结肠运动活动和内脏疼痛增加的作用和机制，将对功能性肠道疾病（如IBS）具有重要的临床意义，其中应激和症状之间的联系越来越多地被认识到。