Molecular Mechanisms Underlying Dendritic Cell Adaptations During Chronic Infection

摘要 慢性病毒感染是一个主要的生物医学问题，其特点是 病原体和免疫系统之间的平衡。这种平衡是通过对 免疫细胞，减弱选定的免疫功能，以最大限度地减少免疫病理，同时保持 病原体在检查中。类似的免疫适应可能在急性发作后被检测到(通常是以短暂的方式)。 感染，但只有在慢性感染期间，病原体的持久性才是持续的。因此， 在慢性感染的背景下研究免疫细胞适应的潜在机制可能不仅 揭示免疫系统的新基础生物学，但也可能解锁新的治疗策略 持续感染的人。这一点最好的例证是T细胞耗尽的发现和他们的 抑制受体PD1在淋巴细胞性脉络膜脑膜炎病毒感染ITS中的抑制作用 两个发现扩展到人类的许多感染以及癌症和 自身免疫性疾病。此外，我们和其他人已经建立了发挥中枢作用的树突状细胞(DC) 在免疫中的作用，也适应于慢性病毒感染的背景，显示出从 骨髓祖细胞、次优成熟和细胞因子产生的改变。 为了了解DC及其祖细胞适应的机制，我们应用了一个切割- 用EDGE生物信息学方法分析LCMV DC前体细胞的转录组和表观基因组 感染的小鼠，并预测几种转录因子(TF)的活性改变。其中，我们披露了 糖皮质激素调节元件结合蛋白1(Gmeb1)抑制DC的发展和 锌指蛋白524(Zfp524)在体外调节细胞因子的产生。这些结果提供了 有证据表明，Gmeb1和Zfp524具有特殊的前景，可以提高我们对DC生物学的基本理解。 我们建议在慢性LCMV期间利用已建立的和持续的DC适应 进一步探讨Gmeb1和Zfp524的新作用和潜在机制。为此，在 目的1和2我们计划在体外和体内充分确定Gmeb1(Aim1)和Zfp524(Aim 2)的作用。 未感染和LCMV感染的小鼠以及人树突状细胞。我们将确定他们的下游目标 基因，并研究这些转录因子在DC调节中的作用与Gmeb1作为一个已知的 糖皮质激素驱动基因表达的增强子，以及芳基-5‘-芳基对Zfp524表达的可能调节 碳氢化合物受体。最后，我们将研究Gmeb1和Zfp524 DC调节与其作用的关系 我们报道的I型干扰素和Toll样受体-7在慢性LCMV感染后DC适应中的作用。 我们的研究将使用尖端技术来揭示DC的分子机制 在体内慢性病毒感染的背景下进行调控。这将大大增加我们的基础知识 研究DC生物学，并推出新的治疗靶点，以利用DC在传染病和非传染性疾病中的作用。

ABSTRACT Chronic viral infections represent a major biomedical problem and are characterized by a long-term equilibrium between the pathogen and the immune system. Such equilibrium is enabled by adaptations of immune cells that attenuate selected immune functions to minimize immunopathology while keeping the pathogen in check. Similar immune-adaptations may be detected (often in a transient manner) after acute infections but are only sustained and relevant for pathogen persistence during chronic infections. Thus, studying the mechanisms underlying immune cell adaptations in the context of chronic infections may not only unveil new basic biology of the immune system but could also unlock new therapeutic strategies for alleviating persistently infected individuals. This is best exemplified by the discovery of T cell exhaustion and their inhibition via the inhibitory receptor PD1 during lymphocytic choriomeningitis virus (LCMV) infection in its natural murine host, two findings that were extended to many infections in humans as well as cancer and autoimmune diseases. In addition, we and others have established that Dendritic Cells (DC), which play central roles in immunity, also adapt in the context of chronic viral infections, showing compromised development from bone marrow progenitors, suboptimal maturation and altered cytokine production. To understand the mechanisms underlying DC and their progenitor adaptations, we applied a cutting- edge bioinformatic approach to analyze the transcriptome and epigenome of DC progenitors from LCMV infected mice, and predicted altered activity of several transcription factors (TFs). Among them, we revealed that Glucocorticoid Modulatory Element Binding Protein 1 (Gmeb1) suppresses DC development and maturation while Zinc Finger Protein 524 (Zfp524) regulates cytokine production in vitro. These results provide evidence that Gmeb1 and Zfp524 hold exceptional promise to improve our basic understanding of DC biology. We propose to take advantage of the well-established and sustained DC adaptations during chronic LCMV infection to further explore the novel roles and underlying mechanisms of Gmeb1 and Zfp524. For that, in Aim#1 and #2 we plan to fully establish the roles of Gmeb1 (Aim1) and Zfp524 (Aim 2) in vitro and in vivo, in both uninfected and LCMV infected mice as well as in human DCs. We will determine their downstream target genes and investigate how these TFs' roles on DC regulation relates to the known function of Gmeb1 as an enhancer of glucocorticoid driven gene expression, and to the putative regulation of Zfp524 expression by Aryl- hydrocarbon receptor. Finally, we will study the relationship of Gmeb1 and Zfp524 DC regulation with the roles of type-I-interferons and toll-like-receptor-7 that we reported for DC adaptations after chronic LCMV infection. Our studies will use cutting-edge technology to unveil the molecular mechanisms by which DCs are regulated in the context of a chronic viral infection in vivo. This will significantly increase our basic knowledge of DC biology and unveil new therapeutic targets to harness DCs in infectious and non-infectious diseases.