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: 8117305
• 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 2013-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8117305
• 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; 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; 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)：压力和促肾上腺皮质激素释放因子(CRF)主要通过CRF1受体对结肠分泌运动功能产生深远影响。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的药理激活可阻止CRF1介导的应激源CRF诱导的结肠肠神经激活和腹泻，而阻断或缺失CRF2可增强结肠对应激的运动反应。第二，CRF1的激活增强了内脏痛反应，而CRF2的激活阻止了辣椒素诱导的原代培养腰骶背根神经节神经元的钙瞬变。第三，CRF导致同时表达CRF1/CRF2的细胞比只表达CRF1的细胞产生更少的cAMP。基于这些关键的观察，我们假设在啮齿类动物中，外周CRF2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，确定CRF2在急、慢性应激诱导的结肠运动反应中作为应激应对机制的生理作用。这将通过阻断或删除CRF2以及阻断神经递质通路和证明应激和外源性神经刺激在体内和体外诱导CRF配体释放来实现。特定目的2将测试CRF2阻止CRF1介导的乙酰胆碱释放，并促进纵向肌肉肌间神经丛组织和原代结肠肌间神经细胞培养的抑制性神经递质释放。我们将研究CRF1-CRF2在天然细胞和转基因细胞中可能的相互作用，以深入了解CRF1-CRF2信号的串扰。通过对分离的结肠传入神经和体外培养的背根节神经元进行体内功能、电生理和分子检测，确定外周CRF2的激活是否通过抑制盆腔传入神经和腰骶背根神经节神经元来抑制应激诱导的内脏痛敏化。阐明外周CRF2抑制应激和CRF相关的结肠运动改变和内脏高敏感性的生理作用和机制，将对肠易激综合征等功能性疾病具有重要的临床意义。在应激、CRF1信号通路和症状之间的联系日益被认识。 公共卫生相关性：拟议的研究旨在建立结肠中CRF2受体信号作为压力适应系统的功能，以维持结肠运动和疼痛反应的动态平衡。这项研究与压力引发或加剧的肠道疾病有关，包括肠易激综合征。阐明外周CRF2激活抑制应激或CRF相关的结肠运动活动增加和内脏疼痛的作用和机制将对IBS等功能性肠道疾病具有重要的临床意义，这些疾病的应激和症状之间的联系日益被认识到。