Enteric Neuronal Development as a Determinant of Intestinal Inflammation

描述(由申请人提供)：此申请旨在支持我在哥伦比亚大学的职业发展，由Michael D.Gershon(肠道神经生理学/发育)、Charalabos Potulakis(肠道炎症)和Lloyd Mayer(免疫学)赞助。培训计划包括课程、指导研究和受保护的研究时间。我的研究旨在分析肠道神经系统(ENS)在肠炎症和肠壁神经免疫相互作用的病理生理学中的可能贡献。据报道，炎症性肠病(IBD)或肠神经节细胞瘤病患者肠道炎症区域的肠神经元数量增加。在人类中，不可能确定神经细胞增殖是否是肠道炎症之前的，是肠道炎症的结果，还是导致其严重程度的因素。我们已经使用，作为 在基因模型中，ENS是过度增生的小鼠(NSE-noggin小鼠)或发育不良的小鼠(Hand2+/-小鼠)，以测试ENS增殖是促炎的假说。初步数据显示，与野生型(WT)小鼠相比，nse-noggin和dss诱导的结肠炎的严重程度指标(存活率、临床和组织学评分、致炎分子编码基因的肠道表达、中性粒细胞弹性蛋白酶和p50 NFκB水平)在NSE-noggin小鼠中更高，Hand2+/-小鼠更低。然而，在用二硝基氟苯引起的耳朵迟发性变态反应的严重程度(水肿、T细胞和中性粒细胞浸润，以及IL 1？、干扰素γ和肿瘤坏死因子α的表达)方面，这两种小鼠都没有与西药不同。因此，转基因对炎症的影响仅限于肠道。这些观察结果与假设是一致的，即ENS增生有助于肠道炎症的严重程度，因此也可能与IBD的发病机制有关。我现在建议研究ENS影响肠道炎症的机制。我将确定ENS增生的促炎效应是否源于(I)肠屏障功能、(Ii)先天免疫和(Iii)免疫调节的改变。肠神经元在基线和炎症期间影响TLR4和TLR5信号的能力将被检测。我将确定ENS对上皮紧密连接和基底板的完整性以及跨肠上皮的大分子双向移位的影响。对调节性T细胞(Treg)亚群(来自固有层和脾)的数量、位置和比例以及它们抑制淋巴细胞增殖的能力的分析将被用来检验Es增殖降低Treg数量和/或功能的假设。除IBD外，肠道疾病还会出现肠道炎症，包括坏死性小肠结肠炎、感染性腹泻和肠易激综合征；ENS可能导致其中任何一种或所有疾病。因此，对ENS和炎症效应因子之间相互作用的了解有可能改变对许多肠道疾病的理解，并最终改变对许多肠道疾病的治疗。

DESCRIPTION (provided by applicant): This application is to support my career development at Columbia University under the sponsorship of Michael D. Gershon (enteric neurophysiology/development), Charalabos Pothoulakis (intestinal inflammation) and Lloyd Mayer (immunology). The training plan includes courses, mentored research, and protected research time. My investigation is designed to analyze putative contributions of the enteric nervous system (ENS) to the pathophysiology of intestinal inflammation and neuroimmune interactions in the bowel wall. Increased numbers of enteric neurons have been reported in inflamed regions of the gut in patients with inflammatory bowel disease (IBD) or intestinal neurogangliomatosis. It is impossible to determine in humans whether neuronal hyperplasia predates intestinal inflammation, results from it, or contributes to its severity. We have used, as genetic models, mice in which the ENS is hyperplastic (NSE-noggin mice) or hypoplastic (Hand2+/- mice) to test the hypothesis that ENS hyperplasia is proinflammatory. Preliminary data show that measures of severity (survival, clinical and histological scores, intestinal expression of genes encoding proinflammatory molecules, levels of neutrophil elastase and p50 NFκB) of TNBS- and DSS-induced colitis are higher in NSE- noggin and lower in Hand2+/- mice than in their wild-type (WT) littermates. In neither mouse, however, are differences from WT found in measures of the severity (edema, T cell and neutrophil infiltration, and expression of IL1ß , IFNγ, and TNFα) of delayed type hypersensitivity evoked in the ears with dinitrofluorobenzene. Transgene effects on inflammation are thus limited to the bowel. These observations are consistent with the hypotheses that ENS hyperplasia contributes to the severity of intestinal inflammation and, potentially also therefore, to the pathogenesis of IBD. I now propose to investigate mechanisms by which the ENS affects intestinal inflammation. I will determine whether the proinflammatory effects of ENS hyperplasia are due to altered (i) intestinal barrier function, (ii) innate immunity, and (iii) immunoregulation. The ability of enterc neurons to affect TLR4 and TLR5 signaling at baseline and during inflammation will be examined. I will determine the effect of the ENS on the integrity of epithelial tight junctions and basal laminae as well as bidirectional translocation of macromolecules across the intestinal epithelium. Analyses of numbers, location, and proportions of regulatory T cell (Treg) subsets (from lamina propria and spleen) as well as their ability to inhibit lymphocyte proliferation will e employed to test hypotheses that ENS hyperplasia decreases Treg number and/or function. Intestinal inflammation occurs in intestinal disorders besides IBD, including necrotizing enterocolitis, infectious diarrhea, and irritable bowel syndrome; the ENS may contribute to any or all of them. Knowledge of interactions between the ENS and inflammatory effectors, therefore, has the potential to transform understanding and, ultimately, treatment of many intestinal disorders.