The mineralocorticoidreceptor in myeloid cells - a new player in CNS autoimmunity

我们之前的工作主要集中在T细胞中糖皮质激素受体（GR）在EAE和多发性硬化症（MS）发病机制中的作用。然而，除了GR外，还有另一种能够结合糖皮质激素（GCs）的受体，即矿盐皮质激素受体（MR），它在髓细胞中表达，因此可以介导GCs在神经炎性疾病调节中的相关作用。因此，我们进行了几个试点实验，表明髓细胞中MR的破坏对EAE也有重大影响。因此，后续项目的目的是更详细地探讨MR在GCs控制神经炎症中的作用，并确定其中的机制。在项目的第一部分，我们想要在髓细胞特异性MR敲除小鼠（MRlysM）中研究EAE。这包括EAE过程中不同类型骨髓细胞的详细表型和功能特征，包括外周淋巴器官和中枢神经系统。这些研究将辅以脊髓的免疫组织化学分析。由于MR在骨髓细胞的不同亚型中表达，我们将研究它们的组成是否被改变，以及小胶质细胞在多大程度上有助于观察到的表型。此外，我们想研究致病性T细胞可能会受到髓细胞中MR缺失的间接影响。在第二部分，我们计划分析骨髓细胞的迁移。由于MRlysM小鼠的中枢神经系统巨噬细胞浸润减少，我们将对naïve和EAE小鼠获得的髓系细胞进行体外转移实验。随后，我们将使用双光子显微镜在体内测试核磁共振缺乏是否以及如何影响单核细胞在不同刺激下的迁移。在第三部分中，我们将基于我们的发现，MR拮抗剂alactone®的应用改善了EAE。首先，我们将比较两种不同的应用方案，然后尝试了解药理学MR阻断的机制。总的来说，我们期望我们的研究将阐明MR在髓细胞中对神经炎性疾病的发病机制和治疗的作用，并允许首次评估MR拮抗剂是否适合治疗患者的中枢神经系统炎症。由于这些抑制剂已经在临床应用，我们的结果可能为未来的转化研究铺平道路。

Our previous work focused on the role of the glucocorticoid receptor (GR) in T cells for the pathogenesis of EAE and multiple sclerosis (MS). However, there is another receptor capable of binding glucocorticoids (GCs) besides the GR, namely the mineralocorticoid receptor (MR), which is expressed in myeloid cells and could therefore mediate relevant effects of GCs in the modulation of neuroinflammatory diseases. Therefore we performed several pilot experiments which suggested that disruption of the MR in myeloid cells has a significant impact on EAE as well. Hence, the purpose of the follow-up project is to explore the role of the MR in the control of neuroinflammation by GCs in more detail and to identify the mechanisms involved. In the first part of the project we want to study EAE in myeloid cell-specific MR knock-out mice (MRlysM). This includes a detailed phenotypic and functional characterization of different types of myeloid cells during the course of EAE, both in peripheral lymphoid organs and the CNS. These studies will be complemented by immunohistochemical analyses of the spinal cord. Since the MR is expressed in distinct subtypes of myeloid cells we will investigate whether their composition is altered and to which extent the microglia contributes to the observed phenotype. In addition, we want to study pathogenic T cells which might be indirectly affected by the absence of the MR in myeloid cells. In the second part we plan to analyze migration of myeloid cells. Because CNS infiltration of macrophages is diminished in MRlysM mice we will perform in vitro transmigration assays of myeloid cells obtained from naïve and EAE mice. Subsequently, we will use 2-photon microscopy to test in vivo whether and how MR-deficiency may affect monocyte migration in response to different stimuli. In the third part we will built upon our finding that application of the MR antagonist Aldactone® ameliorates EAE. Initially, we will compare two different application protocols and then try to understand the mechanism underlying pharmacological MR blockade. Collectively, we expect that our studies will clarify the role of the MR in myeloid cells for the pathogenesis and therapy of neuroinflammatory diseases and allow a first assessment of whether MR antagonists might be suitable for the treatment of CNS inflammation in patients. Since such inhibitors are already in clinical use, our results might pave the way for translational studies in the future.