Novel mechanisms of enteric purinergic signaling

许多GI症状和动力障碍，包括特发性炎性肠病（IBD），是由胃肠动力障碍引起的。 直接或间接地与GI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以及通过影响肠道收缩性和推进性来影响肠道运动 能动性近年来，我们已经确定，NAD+和ADP-核糖，而不是ATP，完成突触前和突触后， 结肠中运动抑制性神经递质的突触后标准。该项目将建立在我们的 研究结果，并将追求细胞外嘌呤的释放，代谢和行动的机制， 代谢物，目的是大大提高我们对嘌呤能信号传导的关键机制的理解， 人类的内脏在目标1中，我们将研究ATP，NAD+和ATP的细胞外代谢的关键机制。 ADPR、交叉途径和大样本中嘌呤能代谢途径的区域患病率 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。 嘌呤和代谢物对肌肉收缩性和运动性的连接后活性。特别是要 研究P2 X7受体和小电导Ca 2+激活的K-t-（SK）通道在 PDGFRa+细胞介导对ATP的反应，并将检查嘌呤介导的Ca 2+脱敏 结肠平滑肌中的机制。在目标3中，我们将研究神经元的释放、降解和 细胞外嘌呤核苷酸和代谢物的作用在结肠炎中受到影响。我们将进行研究 在人和非人灵长类动物的结肠中，在具有特定基因缺失的小鼠中，在 组成型表达绿色荧光蛋白的小鼠和结肠炎动物模型。我们将 使用增强的免疫荧光技术检测嘌呤的组成性和诱发性溢出以及细胞外生物转化 高效液相色谱技术沿着免疫组织化学、蛋白质生物化学 荧光激活细胞分选，电生理学和功能方法，以更好地了解 消化道中嘌呤能信号的机制。这项研究有可能推动新的概念， 调节嘌呤介导的机制在远端胃肠道。 相关性（参见说明）： 许多GI症状和运动障碍与GI系统的神经控制缺陷有关。 炎症性肠病（IBD）特别地（例如克罗恩病和溃疡性结肠炎）是导致结肠炎的主要原因。 在美国，胃肠道疾病的比例很大，并造成了重大的经济医疗负担， 发展中国家。该项目将大大提高对肠道嘌呤能信号的认识， Likelv提出了预防或纠正GI疾病包括IBD的新策略

A number of Gl symptoms and motility disorders, including idiopathic inflammatory bowel diseases (IBD), are linked, directly or indirectly, to defects in the neural control of the Gl 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 Gl tract. RELEVANCE (See instructions): Many Gl symptoms and motility disorders are linked to defects in the neural control of the Gl system. Inflammatory bowel disease (IBD) in particular (e.g. Crohn's disease and ulcerative colitis) accounts for a significant proportion of Gl disease and presents a significant economic healthcare burden in the U.S. and the developing worid. This project will greatly enhance knowledge of purinergic signaling in the gut and will likelv suggest novel strategies for preventing or correcting Gl diseases including IBD