Role and mechanism of action of glutamate dehydrogenase in helminth-driven regulation of eicosanoids and type 2 immunity

全世界有超过5亿人受到过敏性哮喘或鼻息肉等慢性炎症性呼吸道疾病的影响。不幸的是，这些患者中有很大一部分患有耐药疾病。在这种情况下，耐人寻味的是，蠕虫寄生虫可以产生抑制过敏性炎症的分子。在拟议的项目中，我们的目标是从机械上表征来自蠕虫寄生虫的免疫调节效应和分子，最终目的是利用这种潜力来治疗呼吸道炎症。到目前为止，我们可以证明肠道寄生虫多回螺旋体的幼虫提取物(“HpbE”)诱导巨噬细胞表型，能够抑制过敏性炎症。特别是，我们可以证明HpbE可以改变巨噬细胞的脂质介质代谢，以调节/抗炎介质如前列腺素E2(PGE2)为主。此外，缺乏环氧合酶2(COX2)的巨噬细胞不再能够抑制过敏免疫反应。此外，我们可以确定HpbE的免疫调节作用的第一分子和机制。在继续提案中，我们现在的目标是验证我们的主要候选蛋白(HPB谷氨酸脱氢酶，GDH)的免疫调节作用，并阐明其作用机制。在提交报告时，我们正在优化HPB GDH的表达和纯化，以使其能够高质量和高数量地进行重组生产。我们还制备了一种抗HPB-GDH的单抗。有了这些工具，我们的目标是研究寄生虫的GDH是否以及如何被转移到宿主免疫细胞，以及这是否导致脂质介质和谷氨酰胺代谢的变化。然后，我们将在过敏和蠕虫(HPB)感染的小鼠模型以及人类巨噬细胞中评估HPB GDH的有效性及其作用机制(S)。通过转录(RNAseq)谱，我们首次获得了表观遗传机制(组蛋白修饰)在总提取物(HpbE)免疫调节作用中的作用线索。通过执行表观遗传学分析(ChIPseq)和阻断潜在的机制靶点(例如HDACs)，我们现在的目标是研究组蛋白修饰如何有助于HpbE和HPB GDH调节巨噬细胞的脂质介质代谢和效应功能。总之，我们的工作将有助于更好地理解过敏性炎症背景下先天免疫反应的调节，并可能促进向新疗法的转化。

More than 500 million people worldwide are affected by chronic inflammatory airway diseases such as allergic asthma or nasal polyps. Unfortunately, a significant part of these patients suffers from therapy resistant disease. In this context, it is intriguing that worm parasites can produce molecules, which suppress allergic inflammation. In the proposed project, we aim to mechanistically characterize immuneregulatory effects and molecules from a worm parasite with the ultimate aim to harness this potential for the therapy of airway inflammation. So far, we could show that a larval extract of the intestinal parasite Heligmosomoides polygyrus bakeri (“HpbE”) induces a macrophage phenotype that is able to suppress allergic inflammation. In particular, we could show that HpbE modifies the lipid mediator metabolism of macrophages to induce a profile, which is dominated by regulatory/ anti-inflammatory mediators such as prostaglandin E2 (PGE2). Moreover, macrophages, which lack the enzyme cyclooxygenase 2 (COX2), were no longer able to suppress allergic immune responses. Furthermore, we could identify first molecules and mechanisms that are responsible for the immuneregulatory actions of HpbE. In the continuation proposal, we now aim to validate the immuneregulatory effects of our major candidate protein (Hpb glutamate dehydrogenase, GDH) and to elucidate its mechanism of action. At the time of submission, we are optimizing the expression and purification of Hpb GDH to allow for its recombinant production in good quality and quantity. We have also raised a monoclonal antibody against Hpb GDH. With these tools in hand, we aim to study if and how GDH from the parasite is shuffled to host immune cells and if this results in a shift in the lipid mediator- and glutamine- metabolism. The efficacy of Hpb GDH and its mechanism(s) of action will then be assessed in mouse models of allergy and helminth (Hpb) infection as well as in human macrophages.Through transcriptional (RNAseq) profiling, we have obtained first hints to a role for epigenetic mechanisms (histone modifications) in the immuneregulatory effects of the total extract (HpbE). By performing epigenetic analyses (ChIPseq) and by blocking potential mechanistic targets (e.g. HDACs), we now aim to investigate how histone modifications may contribute to the modulation of the lipid mediator metabolism and effector functions of macrophages by HpbE and Hpb GDH. In summary, our work will contribute to a better understanding of the regulation of innate immune responses in the context of allergic inflammation and may foster the translation into novel therapies.