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 虽然功能性胃肠（GI）疾病（FGID）是肠梗阻最常见的原因， 在世界范围内，许多患者没有得到充分的治疗，因为目前的治疗经常 无效。治疗的不足很大程度上是由于对潜在的 这些机制对于设计新的治疗方法至关重要。多达一半的FGID患者也患有 情绪障碍有证据支持胃肠道易受遗传干扰的观点， 可以对胃肠道功能和情绪产生持久的影响。因此，可以想象的是，共病的FGID和精神病 这种情况是由遗传变异引起的异常引起的。的发现 FGID和精神共病的病理生理学基础可能会增强对它们的理解。 从而为两者带来新的治疗方法。5-羟色胺（5-HT），这是一个主要的决定因素，肠 和中枢神经系统（ENS和CNS）的发展，也调节FGID相关的症状（GI 运动）以及情绪，可能是FGID发病机制的重要发育调节剂。5-HT 然而，5-HT 4受体的刺激具有最充分研究的促动力、抗伤害性、抗 抑郁症和抗焦虑作用，因此被用于治疗胃肠道动力障碍和情绪 功能障碍然而，奇怪的是，>50%的FGID患者对它们相对无反应。的 5-HT 4治疗失败的原因尚不清楚，这是一个关键的治疗障碍。我们的初步数据 强烈提示对5-HT 4激动剂无反应是由于5-HT 4运输缺陷。虽然 肠道5-HT 4运输的缺陷以前从未被探索过， 在CNS中描述; p11是参与5-HT 4受体转运至细胞的关键衔接分子 表面，在那里受体可用于介导5-HT信号传导。P11也在抑郁症中发挥作用 （p11 KO小鼠表现出抑郁行为，CNS p11转录在以下小鼠模型中受损： 抑郁症和人类自杀受害者）。我们已经发现，在ENS中，如同在CNS中一样，肠道p11是共同的。 p11与5-HT 4受体共同表达，在那里它们共免疫沉淀，这表明p11与5-HT 4相互作用， 此外，p11影响5-HT 4受体介导的ENS发育和GI运动的作用。我们 因此，假设p11促进5-HT 4受体运输到细胞表面对于5-HT 4-受体的表达是必需的。 ENS发育和功能的调节，因此p11功能障碍是共病FGID的基础， 萧条在本申请中，我们将探讨：（1）p11-5-HT 4相互作用对有效GI 运动性利用体内和离体研究±选择性5-HT 4激动剂的综合阵列， （2）如果p11对情绪（抑郁/焦虑），ENS发育， 和胃肠道运动依赖于粘膜或肠神经元p11，使用新的转基因小鼠，选择性缺乏 肠上皮或ENS中的p11;（3）肠5-HT 4运输和功能是否依赖于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.