Functional analysis of the immune modulator sCD83 in pathogenesis and therapy of inflammatory bowel diseases

在这个项目中，我们追求以下3个主要目标：目标1：在我们最近的工作中，我们可以证明sCD83能够在小鼠DNBS结肠炎模型中预防急性炎症的发展。然而，DNBS-结肠炎模型不能概括人IBD的所有特征。因此，对于sCD83的未来临床开发，在不同的结肠炎模型中显示其有效性是绝对重要的。因此，我们将使用恶唑酮模型分析sCD 83的治疗效果。目标二：调节性T细胞是维持免疫稳态和建立对肠道细菌和食物耐受性的关键参与者。因此，靶向/调节TdR代表了调节IBD患者中致病性免疫应答的新的且非常有前途的策略。以前我们可以证明，在鼠以及人TCFs上，CD83表达在活化后高度且快速地上调。然而，CD83对TGFAP的确切功能作用仍然完全未知。为了获得进一步的见解，我们产生了条件性KO小鼠，其中CD83表达在FoxP3阳性调节性T细胞上特异性缺失。在这些动物的帮助下，我们现在可以在体外和体内破译CD83对TGFAP的功能作用。对于体内研究，我们将使用过继转移结肠炎模型，这是研究调节性T细胞在结肠炎中的功能的最佳动物模型。目标3：已经表明，在激活时释放大量趋化因子和细胞因子的先天淋巴样细胞对于胃肠道粘膜中的调节性和炎性免疫应答是重要的。ILC可分为三组（1 ILC、2 ILC和3 ILC）。组1 ILC产生IFN-γ并表达T-bet（ILC1）或T-bet和Eomes（NK细胞）;第2组ILC包括标记转录因子RORa和GATA 3并释放IL-5和IL-13;并且所有三种第3组ILC都由RORgt指导：类软骨组织诱导细胞（LTi）需要芳香烃受体（Ahr）并释放IL-17和IL-22，而NK细胞受体阳性ILC3需要Ahr和T-bet产生IL-12、IL-22和IFN-g。产生IL-17、IL-22和IFN-g的NK细胞受体阴性ILC3依赖于RORgt和T-bet。虽然第3组ILC细胞保护肠病理，第1组ILC亚群促进粘膜损伤。第2组ILC在IBD背景下的功能作用尚未完全了解。在此，我们将使用Rag1阴性小鼠的过继转移结肠炎模型研究sCD83是否影响胃肠道中的肠道先天淋巴细胞（数量和功能）。

Within this project we pursue the following 3 major aims: Aim 1: In our recent work, we could show that sCD83 is able to prophylactically prevent the development of acute inflammation in the murine DNBS colitis model. However, the DNBS-colitis model cannot recapitulate all features of human IBD. Thus, for the future clinical development of sCD83 it is absolutely vital to show its efficacy in different colitis models. Therefore we will analyze the therapeutic effects of sCD83 using the Oxazolone model. Aim 2: Regulatory T cells are crucial players in order to maintain immune homeostasis and to establish tolerance to commensal bacteria and food in the intestine. Thus, targeting / modulation of Tregs represent new and very promising strategies to modulate pathogenic immune responses in IBD patients. Previously we could show that on murine as well as on human Tregs CD83 expression is highly and rapidly upregulated after activation. However, the precise functional role of CD83 on Tregs is still completely unknown. In order to gain further insights, we generated conditional KO mice, whereby CD83 expression is specifically deleted on FoxP3 positive regulatory T cells. With the help of these animals we can now decipher the functional role of CD83 on Tregs in vitro as well as in vivo. For in vivo investigations we will use the adoptive transfer colitis model which is the best animal model to study the function of regulators T cells in colitis. Aim 3: It has been suggested that the innate lymphoid cells, that release high amounts of chemokines and cytokines upon activation, are important for regulatory and inflammatory immune responses in the mucosa of the GI tract. ILCs can be divided into three groups (1 ILC, 2 ILC and 3 ILC). Group 1 ILCs produce IFN-g and express T-bet (ILC1) or T-bet and Eomes (NK cells); group 2 ILCs include the signature transcription factors RORa and GATA3 and release IL-5 and IL-13; and all three group 3 ILCs are directed by RORgt: Lymphoid tissue-inducer (LTi) cells require the aryl hydrocarbon receptor (Ahr) and release IL-17 and IL-22, while NK cell receptor-positive ILC3s require Ahr and T-bet producing IL-12, IL-22 and IFN-g. IL-17, IL-22 and IFN-g producing NK cell receptor-negative ILC3s depend on RORgt and T-bet. While group 3 ILC cells protected from intestinal pathology, group 1 ILC subsets promote mucosal damage. The functional role of group 2 ILCs in the context of IBD is not fully understood. Here, we will investigate if sCD83 influences intestinal innate lymphoid cells (numbers and function) in the GI tract using the adoptive transfer colitis model in Rag1 negative mice.