Role of enteric glia in acute and chronic inflammation

肠胶质细胞(EGC)沿完整的肠道分布，定位于维持肠道内环境稳定的所有部位。EGC与常驻巨噬细胞、上皮细胞和神经密切接触。与此同时，我们知道EGC在肠道炎症中起着至关重要的作用，这在患有严重空肠回肠炎的EGC去除的转基因小鼠身上显示出来。在术后肠梗阻(POI)的模型中，我们最近证明MyD88或IL-1受体1型(IL1R1)缺陷的小鼠可以免受POI的影响。我们发现人和小鼠EGC表达IL1R1，培养的EGC在IL-1刺激下释放IL-6和MCP-1。三种典型的激活标志物GFAP、Nestin和S100B的表达增加证实了POI过程中EGC的激活。此外，我们在化学诱导(DSS)慢性结肠炎的小鼠模型中证明了EGC的激活。这些数据指向EGC的促炎功能，并无疑表明EGC参与了肠道炎症。然而，它们在肠道疾病状态下的意义和详细功能尚不清楚。在这个项目中，我们主要关注三个问题：(1)EGC特异性IL-1信号的意义将在条件性基因敲除小鼠(GFAPcre+/-/Myd88fl/fl)中进行分析，这些小鼠在EGC中缺乏MyD88和IL-1R1信号。在POI模型中，基因表达和流式细胞术以及收缩和运动测量将在术后时间进程中进行。在这些小鼠的DSS-结肠炎模型中，我们将重点研究来自这些小鼠的粘膜探针的肠道屏障功能。我们将测量一氧化氮中间体和其他参与屏障动态平衡的蛋白质。此外，屏障的完整性将由Ussing小室实验在合作工作中确定。(2)众所周知，神经递质可以调节肠道炎症。在此，我们关注在IL-1引发的炎症过程中，嘌呤能、胆碱能以及交感/肾上腺素能对EGC功能的影响。将在选择性神经递质受体(ANT)激动剂和IL-1刺激下体外培养EGC，并在小鼠疾病模型中进行选择性外科去神经研究(3)最后，我们将研究EGC与驻留巨噬细胞的相互作用。后者在肠道炎症的触发阶段发挥关键作用，特别是在POI中。在两种细胞类型的共培养中，将分析EGC特异性S100B免疫激活剂的释放及其对巨噬细胞的影响。在GFAPcre+/-/Myd88fl/fl中的体内实验将有助于评估该途径在POI中的意义。综上所述，我们期待对EGC的免疫功能有新的见解，这可能有助于治疗或预防急慢性炎症性肠道疾病。

Enteric glial cells (EGC) are distributed along the complete intestine and are localized in all positions relevant to maintain enteral homeostasis. EGC stay in close proximity to resident macrophages, epithelial cells and nerves. Meanwhile we know that EGC crucially participate in intestinal inflammation as shown within EGC-ablated transgenic mice that suffer from a severe jejuno-ileitis. This points toward an immunoregulatory function of EGC.IIn a model of postoperative ileus (POI), an acute intestinal inflammation and dysmotility, we recently demonstrated that mice deficient for MyD88 or IL-1 receptor type 1(IL1R1), were protected from POI. We found that IL1R1 was expressed by human and mouse EGC and cultured EGC released Interleukin-6 and MCP-1 in response to IL-1 stimulation. EGC activation during POI was confirmed by increased expression of three prototypical activation markers, GFAP, Nestin and S100B. Furthermore, we demonstrated an EGC activation in a mouse model of chemically induced (DSS) chronic colitis. These data point toward a proinflammatory function of EGC and undoubtedly demonstrate involvement of EGC in intestinal inflammation. However, their significance and detailed function in intestinal disease states is unknown. In this project we focus on three major question:(1) The significance of an EGC specific IL-1 signalling will be analysed within conditional knockout mice (GFAPcre+/-/Myd88fl/fl), deficient for MyD88 and IL-1R1 signalling within EGC. In a POI model, gene expression and flow cytometry as well as contractility and motility measurements will be performed in a postoperative time course. In a DSS-colitis model in these mice we will focus on intestinal barrier function of mucosa probes from these mice. We will measure nitric oxide intermediates and other proteins involved in barrier homeostasis. Additionally, barrier integrity will be determined by Ussing chamber experiments in a collaborative work. (2) Neurotransmitters are known to modulate intestinal inflammation. Herein we focus on purinergic, cholinergic but also sympathetic/adrenergic effects on EGC function during IL-1-triggered inflammation. In vitro cultures of EGC under selective neurotransmitter receptor (ant)agonism and IL-1 stimulation and selective surgical denervation studies in the murine disease models will be performed (3) Finally, we will investigate the interaction of EGC and resident macrophages. The latter play a key role in the trigger phase of intestinal inflammation, particularly in POI. In cocultures of both cell types, release of the EGC-specific S100B immune activator and its effects on macrophages will be analysed. In vivo experiments in GFAPcre+/-/Myd88fl/fl will help to evaluate the significance of this pathway in POI. Subsumed we expect new insights about the immunological function of EGC that could be helpful in the treatment or prevention of acute or chronic inflammatory intestinal diseases.