Novel mechanisms of enteric purinergic signaling

许多胃肠道症状和动力障碍，包括特发性炎症性肠病(IBD)， 直接或间接地与胃肠系统的神经控制缺陷有关。神经源性嘌呤是中枢 通过在结肠中提供紧张性抑制并通过影响肠道的收缩和推进来促进肠道运动 能动性。近年来，我们已经确定NAD+和ADP-核糖，而不是ATP，实现突触前和 结肠运动抑制性神经递质的突触后标准。这个项目将建立在我们的 并将探讨胞外嘌呤类物质的释放、代谢和作用机制 代谢产物，目的是极大地提高我们对嘌呤能信号转导的关键机制的理解 人类的直觉。在目标1中，我们将研究ATP，NAD+和ATP的胞外代谢的关键机制 大体上嘌呤能代谢通路的ADPR、交叉通路和区域流行率 肠子。在目标2中，我们将研究结肠和结肠中嘌呤能调节的复杂性。 嘌呤及其代谢物对肌肉收缩和运动的节后活性。特别是，我们将 探讨钙激活的K-t-(SK)通道与P2X7受体的关系 PDGFRA+细胞在介导对ATP的反应中的作用并将检测嘌呤介导的钙脱敏 结肠平滑肌的作用机制。在目标3中，我们将研究神经元的释放、降解和 细胞外的嘌呤核苷酸和代谢产物在结肠炎中的作用受到影响。我们将进行我们的研究 在人类和非人类灵长类动物的结肠上，在具有特定基因缺失的小鼠身上，在报告菌株中 绿色荧光蛋白结构性表达的小鼠，以及结肠炎的动物模型。我们会 用增强的方法检测嘌呤的构成和诱发溢出及胞外生物转化 高效液相色谱技术与免疫组织化学、蛋白质生物化学、 更好地理解荧光激活的细胞分类、电生理学和功能方法 肠道中的嘌呤能信号机制。这项研究有可能推动新的概念在 远端胃肠道中的嘌呤调节机制。

A number of GI symptoms and motility disorders, including idiopathic inflammatory bowel diseases (IBD), are linked, directly or indirectly, to defects in the neural control of the GI system. Neurogenic purines are central to gut motility by providing tonic inhibition in the colon and by influencing gut contractility and propulsion motility. In recent years we have determined that NAD+ and ADP-ribose, but not ATP, fulfill presynaptic and postsynaptic criteria for a motor inhibitory neurotransmitter in the colon. This project will build upon our findings and will pursue the mechanisms of release, metabolism and action of extracellular purines and metabolites with the goal to greatly improve our understanding of key mechanisms of purinergic signaling in the human gut. In Aim 1 we will investigate key mechanisms of extracellular metabolism of ATP, NAD+ and ADPR, intersecting pathways, and regional prevalence of purinergic metabolic pathways in the large intestine. In Aim 2 we will investigate the complexities of purinergic regulation in the colon and the postjunctional activities of purines and metabolites on muscle contractility and motility. In particular, we will investigate the involvment of P2X7 receptors and small conductance Ca2+-activated K-t- (SK) channels in PDGFRa+ cells in mediating responses to ATP and will examine purine-mediated Ca2+ desensitization mechanisms in colonic smooth muscle. In Aim 3 we will investigate how neuronal release, degradation and action of extracellular purine nucleotides and metabolites are affected in colitis. We will conduct our studies on colons from human and non-human primates, in mice with specific gene deletions, in reporter strains of mice with constitutive expression of green fluorescence proteins, and in animal models of colitis. We will examine constitutive and evoked overflow and extracellular biotransformation of purines using enhanced high performance liquid chromatography techniques along with immunohistochemistry, protein biochemistry, fluorescence-activated cell sorting, electrophysiology, and functional approaches to better understand mechanisms of purinergic signaling in the gut. This research has the potential to advance new concepts in regulatory purine-mediated mechanisms in the distal GI tract.