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: 9116211
• 负责人: MILLION MULUGETA
• 金额: $ 26.28万
• 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 2018-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9116211
• 关键词: Abdominal Pain; Acute; Affect; Biology; CRF receptor type 1; CRF receptor type 2; Chemicals; Chronic; Chronic stress; Code; Colon; Colorectal; Data; Disease; Enteral; Failure; Functional disorder; Future; G-Protein-Coupled Receptors; Gene Expression; Gene Silencing; Genetic; Grant; Habits; Health; Healthcare; Homeostasis; Human; Intestines; Irritable Bowel Syndrome; Knockout Mice; Lead; Measurement; Mediating; Mediator of activation protein; Medical; Modeling; Molecular; Monitor; Motor; Motor Pathways; Mus; Neurons; Neurotransmitters; Nitric Oxide; Nitric Oxide Synthase Type I; Nociception; Pain; Pathway interactions; Patients; Peptides; Peripheral; Population; Proto-Oncogene Proteins c-akt; Public Health; RNA Interference; RNA Splicing; Rattus; Receptor Activation; Receptor Gene; Recruitment Activity; Recurrence; Reflex action; Regulation; Research; Risk Factors; Rodent; Sensory; Signal Transduction; Site; Small Interfering RNA; Spinal; Spinal Cord; Stress; Stress and Coping; System; Taxes; Testing; Time; Tissues; Transgenic Mice; Triad Acrylic Resin; Untranslated RNA; Variant; Visceral; base; biological adaptation to stress; coping; coping mechanism; in vivo; neuronal excitability; novel; novel therapeutic intervention; overexpression; pressure; receptor; release factor; response; sensor; stressor; targeted therapy trials; tau Proteins; tau phosphorylation; tool

DESCRIPTION (provided by applicant): IBS patients have recurrent abdominal pain associated with altered bowel habits. The mechanisms of IBS are poorly understood and therapies are lacking. A compromised stress response is a key risk factors for IBS. The primary mediator of stress is the peptide cortocotropin releasing factor (CRF). In the last granting period we have shown that in contrast to CRF1, CRF2 receptors suppress the colonic sensorimotor responses and that a compromised CRF2 function exacerbates the colonic response to stress. The mechanism how CRF2 mediates stress resiliency in the colon is not known. In preliminary data, we show that a) CRF2 activates colonic neuronal NOS and NO release and involves VIP to inhibit colonic motor response, b) human tau- overexpressing mice display altered colonic response to mild stress and c) CRF2 but not CRF1 activation suppresses stress or CRF-induced enteric and primary afferent neuronal tau phosphorylation. Based on data from last grant and the preliminary data, we hypothesize that CRF2 in the colon subserves a stress-coping function through activation of enteric NO and modulation of neuronal tau, a novel enteric stress pathway, and that altered CRF2 signaling will lead to maladaptive colonic sensorimotor responses to stress. This will be tested under three aims. Aim 1 will determine the functional interaction of the CRF2-NO-VIP triad. CRF2 mediated molecular activation of nNOS, NO release, VIP activation and colonic contraction in vivo will be monitored in naive and stressed rats. Regulation of colonic CRF2 receptor splices variants under stress will be assessed to determine variants that are associated with perturbed colonic motor homeostasis Aim 2 will characterize a novel stress-tau-gut pathway and will dissect the effects and mechanism of stress-induced enteric neuronal tau modulation in rats. The identity of colonic enteric neurons with tau phophorylation, the colonic reflex and the suppression of stress-induced tau phophorylation by CRF2 will be investigated. Aim 3 will test the hypothesis that stress or CRF-induced modulation of visceral nociception involves enteric and spinal neuronal tau phosphorylation. Myenteric and DRG neuronal tau and neuronal excitability along with visceral nocicption in stressed and non-stressed rats will be assessed. Whether the CRF2 mediated suppression of visceral nociception is associated with the suppression of tau phosphorylation will be determined. Enteric and spinal tau modulation and site specific deletion of CRF2 (siRNA) will be used. Overall, the studies will use pharmacological, genetic, tissue, cellular and molecular tools to dissect the mechanisms how CRF2 receptor activation suppresses stress-related colonic sensorimotor responses. Unraveling these CRF2 mediated mechanisms in the gut response to stress will have significant impact in the understanding of stress-induced gut sensorimotor alteration and in guiding future novel therapeutic approaches to stress related diseases such as IBS.

描述（由申请人提供）：IBS 患者患有与排便习惯改变相关的反复腹痛。人们对 IBS 的机制知之甚少，也缺乏治疗方法。应激反应受损是肠易激综合症的一个关键风险因素。压力的主要介质是肽促肾上腺皮质激素释放因子（CRF）。在最后的授权期间，我们已经表明，与 CRF1 相比，CRF2 受体抑制结肠感觉运动反应，并且 CRF2 功能受损会加剧结肠对压力的反应。 CRF2 介导结肠应激弹性的机制尚不清楚。在初步数据中，我们表明：a) CRF2 激活结肠神经元 NOS 和 NO 释放，并涉及 VIP 抑制结肠运动反应，b) 人 tau 过表达小鼠表现出对轻度应激的结肠反应改变，c) CRF2 但不是 CRF1 激活抑制应激或 CRF 诱导的肠和初级传入神经元 tau 磷酸化。根据上次资助的数据和初步数据，我们假设结肠中的 CRF2 通过激活肠道 NO 和调节神经元 tau（一种新的肠道应激途径）来促进应激应对功能，并且 CRF2 信号传导的改变将导致适应不良结肠对压力的感觉运动反应。这将在三个目标下进行测试。目标 1 将确定 CRF2-NO-VIP 三联体的功能相互作用。将在幼稚和应激大鼠中监测体内 CRF2 介导的 nNOS 分子激活、NO 释放、VIP 激活和结肠收缩。将评估应激下结肠 CRF2 受体剪接变异的调节，以确定与结肠运动稳态紊乱相关的变异。目标 2 将表征一种新的应激-tau-肠通路，并将剖析应激诱导的肠神经元 tau 调节的影响和机制在老鼠身上。将研究具有 tau 磷酸化的结肠肠神经元的身份、结肠反射以及 CRF2 对应激诱导的 tau 磷酸化的抑制。目标 3 将检验以下假设：压力或 CRF 诱导的内脏伤害感受调节涉及肠和脊髓神经元 tau 磷酸化。将评估应激和非应激大鼠的肌间和背根神经节神经元 tau 蛋白和神经元兴奋性以及内脏伤害。将确定 CRF2 介导的内脏伤害感受抑制是否与 tau 磷酸化抑制相关。将使用肠和脊髓 tau 蛋白调节以及 CRF2 (siRNA) 的位点特异性删除。总体而言，这些研究将使用药理学、遗传、组织、细胞和分子工具来剖析 CRF2 受体激活如何抑制应激相关的结肠感觉运动反应的机制。解开这些 CRF2 介导的肠道应激反应机制，将对理解应激引起的肠道感觉运动改变以及指导未来治疗应激相关疾病（如 IBS）的新方法产生重大影响。