Genetic Mechanisms of Tissue-Resident Macrophage Maintenance and Function

总结 巨噬细胞是先天免疫系统的关键组成部分，它对局部环境进行采样， 并使组织恢复体内平衡。不同的巨噬细胞群体在这些疾病中发挥独特的作用。 流程.来源于循环单核细胞的巨噬细胞被迅速募集至感染， 炎症，并且通常是短暂的。相比之下，长寿命的组织驻留巨噬细胞（TRM） 来源于胎肝细胞，在没有感染的情况下在维持体内平衡中起重要作用。 虽然单核细胞衍生的巨噬细胞是明确的，但由于实验的限制，仍然存在许多 关于TRM如何维护和有助于调节当地环境的开放性问题。到 为了弥补这些知识上的关键空白，我的研究小组正在开发不同TRM的新体外模型 然后可以使用功能遗传学来探测这些群体。我们最近开发了一种体外模型， 肺特异性TRM，肺泡巨噬细胞（AM），维持AM特异性标志物的表达， 功能使用这个模型，我们在AM样细胞中设计了一个全基因组敲除文库， 使用我们定制的筛选管道进行基因筛选。在接下来的五年里，我的研究小组 我将利用这一创新资源来剖析与AM维持相关的潜在生物机制 和功能我们将使用一种新的方法全面定义维持细胞处于AM样状态所需的基因。 将迭代遗传筛选与深入的功能表征相结合。这些实验将 揭示了在稳态过程中AM中激活的全新信号和转录网络。同时， 我们将比较骨髓源性巨噬细胞和骨髓源性巨噬细胞对核心巨噬细胞功能的遗传控制， （BMDM）和AM样细胞。虽然BMDM和BMDM之间存在代谢和转录差异， 但是，这些差异如何改变巨噬细胞功能的遗传控制， 吞噬作用我们将在BMDM和AM样细胞中完成筛选，以探测不同细胞的吞噬作用。 货物.这些数据集将定义控制核心巨噬细胞功能的共享和独特途径， 阐明基本生物过程的新机制。最后，我的研究小组将奠定 通过优化细胞转移，为解剖完整动物AM中的遗传途径奠定基础， 筛选管道使用这个模型，我们将揭示关键AM基因的体内作用，并确定新的 AM维持肺内稳态所需的途径。实现这些目标将使我的研究 小组了解控制AM的基本机制，这在以前是不可能的。我们长久以来- 长期目标是通过以下方式扩展这些方法和发现，以更广泛地了解其他TRM人群 确定功能和维护的共享机制。

Summary Macrophages are critical components of the innate immune system that sample the local environment, respond to stimuli and return tissues to homeostasis. Distinct macrophage populations play unique roles in these processes. Macrophages derived from circulating monocytes are rapidly recruited to infections, are inflammatory, and are generally short-lived. In contrast, long-lived tissue resident macrophages (TRMs) are derived from fetal liver cells and play an important role in maintaining homeostasis in the absence of infections. While monocyte-derived macrophages are well defined, due to experimental limitations there remain many open questions regarding how TRMs are maintained and contribute to regulating the local environment. To address these key gaps in knowledge my research group is developing new ex vivo models of distinct TRM populations that can then be probed using functional genetics. We recently developed an ex vivo model for lung-specific TRMs, alveolar macrophages (AMs), that maintain expression of AM-specific markers and function. Using this model we engineered a genome-wide knockout library in AM-like cells that enables rapid forward genetic screens using our customized screening pipeline. Over the next five years my research group will leverage this innovative resource to dissect underlying biological mechanisms related to AM maintenance and function. We will comprehensively define the genes required to maintain cells in the AM-like state using a combination of iterative genetic screens with in-depth functional characterization. These experiments will uncover entirely novel signaling and transcriptional networks activated in AMs during homeostasis. In parallel, we will compare the genetic control of core macrophage functions between myeloid-derived macrophages (BMDMs) and AM-like cells. While there are metabolic and transcriptional differences between BMDMs and AMs, it remains entirely unknown how these differences alter genetic control of macrophage functions like phagocytosis. We will complete screens in both BMDMs and AM-like cells probing phagocytosis of distinct cargo. These datasets will define shared and unique pathways that control core macrophage functions and will illuminate new mechanisms of fundamental biological processes. Finally, my research group will lay the groundwork for dissecting genetic pathways in AMs in intact animals by optimizing a cell transfer and screening pipeline. Using this model, we will uncover the in vivo role of key AM genes and identify new pathways required for AMs to maintain lung homeostasis. Accomplishing these goals will position my research group to understand the underlying mechanisms controlling AMs in detail not previously possible. Our long- term goal is to expand these approaches and findings to more broadly understand other TRM populations by identifying shared mechanisms of function and maintenance.