Linkage of s100a10 (p11) to enteric 5-HT4-mediated serotonergic signaling roles in GI motility, enteric nervous system development, and co-morbid dysfunction of gut and brain

项目摘要 尽管功能性胃肠道(GI)紊乱(FGID)是导致肠道疾病的最常见原因 在世界范围内，许多患者没有得到充分的治疗，因为目前的治疗方法经常是 效果不佳。治疗的不足在很大程度上是由于对潜在的 对设计新的治疗方法至关重要的机制。多达一半的FGID患者也患有 情绪障碍。有证据支持这样一种观点，即胃肠道容易受到基因扰动的影响 能对胃肠功能和情绪产生持久的影响。因此可以想象，一种共病的FGID和精神病 这种情况是由基因变异导致的异常引起的。新发现的 FGID和精神疾病共病的病理生理学基础可能会加强对它们的理解 因此导致了针对两者的新的治疗方法。5-羟色胺(5-羟色胺)，这是肠道的一个主要决定因素 和中枢神经系统(ENS和CNS)的发育，也调节FGID相关症状(GI 运动性)和情绪一样，可能是FGID发病的重要发育调节因子。它是5-羟色胺 然而，刺激5-HT4受体是研究最充分的促动力、抗伤害性、抗... 抑郁和抗焦虑作用，因此被用于治疗胃肠动力障碍和情绪 功能障碍。然而，奇怪的是，50%的FGID患者对它们相对反应迟钝。这个 5-HT4治疗失败的原因尚不清楚，这使这成为一个关键的治疗障碍。我们的初步数据 强烈提示，对5-HT4激动剂的反应失败是由于5-HT4转运的缺陷。虽然 肠道5-HT4转运的缺陷以前从未被探索过，这种异常现象已经被研究过 P11是参与5-HT4受体向细胞转运的关键接头分子。 表面，在那里受体变得可用来调节5-羟色胺信号。P11在抑郁症中也起作用。 (p11KO小鼠表现出抑郁行为，CNS p11转录受损 抑郁症和人类自杀受害者)。我们已经发现，在ENS中，就像在CNS中一样，Gut p11是协同- 与5-HT4受体共沉淀表达，提示p11与5-HT4相互作用。 肠道和p11影响5-HT4受体介导的ENS发育和胃肠动力的作用。我们的 因此，假设p11促进5-HT4受体到细胞表面的运输对5-HT4- ENS发育和功能调节以及p11功能障碍因此是FGID和FGID并存的基础 抑郁症。在本应用程序中，我们将探讨：(1)p11-5-HT4相互作用对有效的GI有多重要 利用一系列全面的体内和体外研究？选择性5-HT4激动剂， (2)如果p11对情绪(抑郁/焦虑)、ENS发育、 而胃肠动力依赖于粘膜或肠道神经元p11，使用选择性缺乏的新型转基因小鼠 P11在肠上皮或ENS中的表达；(3)肠内5-HT4的转运和功能是否依赖于p11。

Project Summary Although functional gastrointestinal (GI) disorders (FGIDs) are the most common causes of bowel dysfunction worldwide, many patients are inadequately treated because current therapies are frequently ineffective. The inadequacy of therapy is largely due to an incomplete comprehension of underlying mechanisms that are critical for the design of new treatments. Up to half of individuals with FGIDs also suffer from mood disorders. Evidence supports the idea that the GI tract is vulnerable to genetic perturbations that can exert lasting effects on GI function and mood. It is thus conceivable that a co-morbid FGID and psychiatric condition result from abnormalities occurring as the result of a genetic variant. Discovery of the pathophysiology underlying FGIDs and psychiatric co-morbidities is likely to enhance understanding of their relationship and thus lead to novel therapies for both. Serotonin (5-HT), which is a major determinant of enteric and central nervous system (ENS and CNS) development and also modulates FGID-related symptoms (GI motility) as well as mood, may be an important developmental modulator of FGID pathogenesis. It is 5-HT stimulation of the 5-HT4 receptor, however, that has the most well-studied prokinetic, anti-nociceptive, anti- depressive, and anti-anxiety effects and has thus been targeted to treat both GI dysmotility and mood dysfunction. Curiously, however, >50% of patients with FGIDs are relatively unresponsive to them. The reason for 5-HT4 treatment failure is unknown, making this a critical treatment obstacle. Our preliminary data strongly suggest that failure to respond to a 5-HT4 agonist is due to a defect in 5-HT4 trafficking. Although defects in enteric 5-HT4 trafficking have never previously been explored, such abnormalities have been described in the CNS; p11 is a critical adaptor molecule involved in this transport of 5-HT4 receptors to cell surfaces, where the receptors become available to mediate 5-HT signaling. P11 also plays a role in depression (p11KO mice exhibit depressive behaviors and CNS p11 transcription is impaired in mouse models of depression and human suicide victims). We have found that in the ENS, as in the CNS, gut p11 is co- expressed with 5-HT4 receptors where they co-immunoprecipitate, suggesting that p11 interacts with 5-HT4 in the gut and, further, that p11 affects 5-HT4 receptor-mediated actions on ENS development and GI motility. Our hypotheses are thus that p11 facilitation of trafficking of 5-HT4 receptors to cell surfaces is essential for 5-HT4- modulation of ENS development and function and that p11 dysfunction thus underlies comorbid FGID and depression. In this application we will explore: (1) How critical the p11-5-HT4 interaction is for effective GI motility utilizing a comprehensive array of in vivo and ex vivo studies ± the selective 5-HT4 agonist, prucalopride, in WT and p11KO mice; (2) If effects of p11 on mood (depression / anxiety), ENS development, and GI motility depend on mucosal or enteric neuronal p11, using novel transgenic mice that selectively lack p11 in the enteric epithelium or ENS and; (3) If enteric 5-HT4 trafficking and function are p11-dependent.