Deciphering the immunoregulatory network governing antigen presenting myeloid cells

摘要 树突状细胞(DC)负责引导T细胞的反应，巨噬细胞则是重要的调节细胞 组织发炎。这些免疫细胞的一个特点是它们固有的可塑性，可以控制免疫与耐受。 然而，关于共同支配的复杂分子网络，仍有许多未知之处。 造血、炎症和抗原提呈。不完全的理解构成了 说明它们在健康和疾病方面的潜在作用，这也阻碍了成功地制定有效的 免疫疗法。这项拟议研究的长期目标是确定免疫调节的关键作用 蛋白质控制DC和巨噬细胞的分化和免疫反应。我的实验室发表的研究结果 已经开始机械地定义在这些基因中唯一表达的几个重要基因的功能作用 髓系细胞。这些基因包括同种异体移植物炎症因子-1(AIF1)和磷酸二酯酶1b (Pde1b)，其中，使用结合高通量转录转录图谱的组合来鉴定 通过严格的RNAi功能筛选。我的实验室证明，AIF1是选择性地在 传统的1型DC(CDC1)、单核细胞来源的DC(MoDC)和巨噬细胞，并作为支架 以钙反应方式募集蛋白激酶C(PKC)促进炎症和1型极化 免疫反应。此外，AIF1的表达是成功从 造血祖细胞和单核细胞来源的巨噬细胞和巨噬细胞。在…的背景下 疾病，AIF1在DC和巨噬细胞中的表达是启动和持续胰岛素炎所必需的，在 调节效应器对细胞内病原体的反应。在另一项研究中，磷酸二酯酶蛋白 研究发现，Pde1b能抑制蛋白激酶A(PKA)的活性，这种抑制作用依赖于钙离子。 CDC1、MoDC和巨噬细胞中的环核苷酸水平促进免疫效应反应。因此，我的 研究小组已经开始解开Pde1b和AIF1如何协同工作，通过平衡来管理免疫力 PKC与PKA活动。尽管这些初步发现很重要，但在理解上仍然存在几个差距 这些基因如何控制免疫生物学的分子力学。因此，我们的研究建立在之前的基础上 现在通过使用条件和全局基因敲除小鼠和使用创新的实验工具进行的研究 严格研究体内的机械作用。在接下来的五年里，我的实验室将实现以下主要目标 年：(1)描述AIF1和Pde1B如何在体内控制DC和巨噬细胞的分化；(2)描述 其他关键新免疫调节基因协调免疫反应的细胞内过程；(3) 确定AIF1在启动炎症和维持自身反应性T细胞反应中的作用； 以及(4)确定细胞内病原体如何通过破坏钙信号来拮抗AIF1和Pde1b 和环核苷酸水平来逃避宿主免疫。所获得的知识将填补我们对 DC和巨噬细胞生物学，并对管理免疫的分子网络提供了重要的见解。

SUMMARY Dendritic cells (DC) are responsible for directing T cell responses and macrophages important for modulating tissue inflammation. A hallmark of these immune cells is their inherent plasticity to govern immunity vs. tolerance. However, much remains unknown regarding the complex molecular networks that collectively govern hematopoiesis, inflammation and antigen presentation. Incomplete understanding presents major obstacles to delineating their underlying roles in health and disease, which has also hindered success in developing effective immunotherapies. The long-term goal of the proposed research is to determine how pivotal immunoregulatory proteins govern DC and macrophage differentiation and immune responses. Published findings by my laboratory have begun to mechanistically define the functional roles of several important genes uniquely expressed in these myeloid cells. These genes, which include Allograft Inflammatory Factor-1 (AIF1) and Phosphodiesterase 1b (Pde1b), among others, were identified using a combination of high throughput transcriptomic profiling coupled with rigorous RNAi functional screening. My laboratory demonstrated that AIF1 is selectively expressed in conventional type 1 DC (cDC1), monocyte-derived DC (MoDC) and macrophages and serves as a scaffold to recruit protein kinase C (PKC) in a calcium-responsive manner to promote inflammation and type 1 polarized immune responses. Furthermore, AIF1 expression was required for successful generation of cDC1 from hematopoietic progenitors and both MoDC and macrophages from monocyte precursors. In the context of disease, AIF1 expression in DC and macrophages is required for initiating and sustaining insulitis and in regulating effector responses to intracellular pathogens. In another line of studies, the phosphodiesterase protein Pde1b was found to depress protein kinase A (PKA) activity in a calcium-dependent manner by regulating cyclonucleotide levels in cDC1, MoDC and macrophages to promote immune effector responses. Thus, my research group has begun to unravel how Pde1b works in concert with AIF1 to govern immunity by balancing PKC vs. PKA activities. As important as these initial findings are, there remains several gaps in understanding the molecular mechanics of how these genes govern immunobiology. As such, our research builds on prior studies by now employing conditional and global knockout mice and use of innovative experimental tools to rigorously study mechanistic roles in vivo. My laboratory will pursue the following major goals over the next five years: (1) delineate how AIF1 and Pde1B govern differentiation of DC and macrophages in vivo; (2) describe the intracellular processes by which other key novel immunoregulatory genes orchestrate immune responses; (3) determine the contributing role of AIF1 in initiating inflammation and sustaining autoreactive T cell responses; and (4) identify how intracellular pathogens antagonize AIF1 and Pde1b through disruption of calcium signaling and cyclonucleotide levels to evade host immunity. Knowledge gained will fill key gaps in our understanding of DC and macrophage biology and provide important insights into the molecular networks governing immunity.