Spinal glia activation in chronic stress-induced visceral hyperalgesia

描述（由申请人提供）：目前的提案首次解决了中枢神经系统中神经免疫激活的作用，作为许多常见功能性胃肠疾病（FGID）包括肠易激综合征（IBS）的内脏疼痛成分的合理机制。尽管越来越多的证据表明脊髓胶质细胞在介导持续性疼痛的机制中的作用，但其在内脏疼痛中的作用尚未得到评估。我们提出的一般假设是，慢性应激是IBS症状首次发作或恶化的关键因素，它触发了由神经元和免疫细胞（神经胶质细胞）组成的脊髓网络的激活，在内脏伤害感觉的调节中起着核心作用。利用慢性避水应激大鼠模型，我们提出表征应激诱导的脊髓胶质细胞激活在内脏敏感性调节中的作用，并确定参与内脏痛觉过敏开始和维持的分子途径。我们的第一个具体目标是评估慢性应激期间和之后脊髓胶质细胞激活的时间概况，并测试胶质细胞特异性抑制剂减轻应激诱导的内脏痛觉过敏的能力。第二个具体目标涉及到连接慢性应激和脊髓胶质细胞激活的分子机制的表征。本申请中提出的实验设计包括对不同药物治疗（拮抗剂、激动剂、寡核苷酸反义剂）反应的内脏敏感性的行为评估，并结合使用Western blotting、多重ELISA、免疫组织化学和定量RT-PCR的体外分析。拟议研究的长期目标是利用选择性敲除动物和胶质/神经元共培养来表征观察到的内分泌-神经-免疫相互作用的信号通路。针对胶质-神经元串扰的特定介质可能为开发新的治疗靶点提供一种创新的方法，用于治疗与应激反应增强相关的慢性疼痛状况。应激诱导的神经胶质神经元信号调节的概念及其在感觉系统长期改变中的意义可以推广到许多其他应激敏感性疼痛情况，包括间质性膀胱炎、非心源性胸痛和纤维肌痛。公共卫生相关性：在目前的建议中，我们提出了慢性应激可能诱导脊髓免疫系统激活的概念，引发一系列影响感觉系统的事件。这种新方法对开发新的治疗靶点具有重要意义，用于治疗与应激反应增强相关的慢性疼痛疾病，包括功能性胃肠道疾病，有效治疗仍然是临床挑战。

DESCRIPTION (provided by applicant): The current proposal, for the first time, addresses the role of neuro-immune activation within the central nervous system as a plausible mechanism underlying the visceral pain component of many common functional gastrointestinal disorders (FGID) including irritable bowel syndrome (IBS). Although increasing evidence has emerged for the role of spinal glia in the mechanisms mediating persistent pain, its implication in visceral pain has not been evaluated. We propose the general hypothesis that chronic stress, known as a key factor in the first onset or exacerbation of IBS symptoms, triggers the activation of a spinal network comprising neurons and immune cells (glia), playing a central role in the modulation of visceral nociception. Using a rat model of chronic water avoidance stress, we propose to characterize the role of stress-induced spinal glia activation in the modulation of visceral sensitivity and determine the molecular pathways engaged in the initiation and maintenance of visceral hyperalgesia. Our first specific aim is to assess the temporal profile of spinal glia activation during and after chronic stress and to test the ability of inhibitors specific of glia to reduce stress- induced visceral hyperalgesia. The second specific aim relates to the characterization of molecular mechanisms linking chronic stress and spinal glial activation. The experimental design proposed in this application includes the behavioral assessment of visceral sensitivity in response to different pharmacological treatments (antagonists, agonists, oligonucleotide antisenses), combined with in vitro analysis using Western blotting, multiplex ELISA, immunohistochemistry and quantitative RT-PCR. The long-term goal of the proposed studies is the characterization of signaling pathways underlying the observed endocrine-neural- immune interactions using selective knockout animals and glia/neurons co-cultures. Targeting specific mediators of the glial-neuronal crosstalk may provide an innovative approach for the development of novel therapeutic targets for the treatment of chronic pain conditions associated with enhanced stress responsiveness. The concept of stress-induced modulation of glial-neurons signaling and its implication in long-term alteration of the sensory system may be generalized to many other stress-sensitive pain conditions, including interstitial cystitis, non-cardiac chest pain and fibromyalgia. PUBLIC HEALTH RELEVANCE: In the current proposal, we have developed the concept that chronic stress may induce activation of the immune system in the spinal cord, initiating a cascade of events that will affect the sensory system. This new approach has considerable implication for the development of novel therapeutic targets for the treatment of chronic pain conditions associated with enhanced stress responsiveness, including functional gastrointestinal disorders, for which effective treatment remains a clinical challenge.