Sensory Cross-Activation in Bowel Dysfunction

项目总结 疼痛在远离病人的地方被察觉，这在人类中很常见。 管风琴。肠功能障碍也是如此。炎症性肠病(IBD)和/或易激惹患者 肠综合征(IBS)通常表现为膀胱多动和躯体疼痛。了解外围设备 疼痛产生和感觉交叉敏化的机制有助于治疗方法的发展 以最小的中枢不良反应治疗疼痛共病。外周神经胶质细胞增多 对它们在调节感觉神经元活动中的作用的认识。背根卫星神经胶质细胞 神经节位于感觉神经元周围，通过SGC网络连接感觉神经元。vbl.使用 基于Cre的hM3Dq的表达通过氯氮平-N-氧化物(CNO)激活神经胶质细胞，我们发现 神经胶质细胞导致降钙素基因相关肽(CGRP)释放到脊髓，这是一种必不可少的 脊髓中枢敏化过程。神经胶质细胞的激活也促进了结肠的过敏， 小鼠的膀胱和后爪。在DRG中，TrkB.T1由SGCs表达，而不是神经元表达。钙(Ca2+) 在SGCs中，hM3Dq和TrkB.T1介导的活性是一种常见的途径。重要的是，使用独特的SGC- 在感觉神经元共培养系统中，我们发现TrkB.T1介导的SGCs的激活导致了 参与疼痛处理的相邻感觉神经元。因此，我们假设TrkB.T1在 神经胶质细胞与神经元相互作用，参与感觉神经元的交叉激活和跨器官敏化。至 验证这一假设，我们将使用外周血中可诱导的条件性TrkB.T1缺失(TrkB.T1cKO)的小鼠 胶质细胞主要来自SGCs和外周胶质细胞表达hM3Dq或hM4Di的小鼠。我们将表演分子 以及结肠-膀胱感觉神经元交叉激活和跨器官敏化的功能分析。 独特的鼠标线(目标1)。TrkB.T1在SGCs中的功能作用是使细胞内钙离子水平升高到 促进神经胶质递质释放。我们已经确定了一些受TrkB.T1调控的胶质细胞介质 通过蛋白质组筛选和转录分析。我们将描述TrkB.T1-Mediated 跨器官背景下的神经胶质传递和神经胶质递质促进的感觉神经元激活 敏化(目标2)。中枢敏化不仅有助于结肠-膀胱的交叉敏化，而且还 是内脏-躯体交叉敏感化的基础。因此，我们将检查TrkB.T1介导的SGC- 感觉神经元串扰促进CGRP中枢释放并导致内脏-躯体交叉敏感化 (目标3)。在这三个目标中，我们将使用不止一种动物模型，并应用于体内和体外 功能和机械学研究的方法。有趣的是，我们的初步数据显示TrkB.T1是 性两面性。因此，我们将在两性中进行我们的实验。我们期待着披露 TrkB.T1在神经胶质细胞-神经元相互作用中的作用 敏化和建议的治疗靶点。

PROJECT SUMMARY It is a common occurrence in human that pain is perceived at a remote location away from the diseased organ. This is also true with bowel dysfunction. Patients with inflammatory bowel diseases (IBD) and/or irritable bowel syndrome (IBS) often experience bladder hyperactivity and somatic pain. Understanding the peripheral mechanisms of pain generation and sensory cross-sensitization helps development of therapeutic approaches with minimum central adverse effects to treat pain comorbidity. Peripheral glial cells are gaining increased recognition for their roles in modulating sensory neuron activity. Satellite glial cells (SGCs) of dorsal root ganglia (DRG) reside around sensory neurons and connect sensory neurons through SGC networks. Using Cre-based expression of hM3Dq to activate glial cells by clozapine-N-oxide (CNO), we show that activation of glial cells leads to an enhanced calcitonin gene-related peptide (CGRP) release to the spinal cord, an essential process in spinal central sensitization. Activation of glial cells also facilitates hypersensitivity of the colon, urinary bladder and hind paw in mice. In DRG, TrkB.T1 is expressed by SGCs but not neurons. Calcium (Ca2+) activity is a common pathway mediated by hM3Dq and TrkB.T1 in SGCs. Importantly, using a unique SGC- sensory neuron co-culture system we show that activation of SGCs mediated by TrkB.T1 leads to activation of adjacent sensory neurons that participate in pain processing. We therefore hypothesize that TrkB.T1 mediates glia-neuron interaction and participates in sensory neuron cross-activation and cross-organ sensitization. To test this hypothesis, we will use mice with inducible conditional TrkB.T1 deletion (TrkB.T1cKO) from peripheral glia mainly from SGCs and mice with hM3Dq or hM4Di expression in peripheral glia. We will perform molecular and functional analysis of colon-bladder sensory neuron cross-activation and cross-organ sensitization in these unique mouse lines (Aim 1). The functional roles of TrkB.T1 in SGCs are to increase the levels of Ca2+ to promote gliotransmitter release. We have identified a number of glial mediators that are regulated by TrkB.T1 in SGCs through proteomic screening and transcriptional analysis. We will characterize TrkB.T1-mediated gliotransmission and gliotransmitter-facilitated sensory neuron activation in the context of cross-organ sensitization (Aim 2). Central sensitization not only contributes to colon-bladder cross-sensitization but also underlies viscero-somatic cross-sensitization. We therefore will examine whether TrkB.T1-mediated SGC- sensory neuron crosstalk contributes to CGRP central release and leads to viscero-somatic cross-sensitization (Aim 3). Throughout the three aims, we will use more than one animal models and apply in vivo and in vitro approaches for functional and mechanistic studies. Interestingly, our preliminary data show that TrkB.T1 is sexually dimorphic. We therefore will perform our experiments in both genders. We anticipate revealing the role of TrkB.T1 in glia-neuron interaction to provide insights in understanding the development of cross-organ sensitization and suggest therapeutic targets.