Examining the Role of IRF8 in Tumor-Associated Macrophage Differentiation and Function

项目概要/摘要 肿瘤相关巨噬细胞 (TAM) 通常是固体中发现的主要免疫细胞类型 人类肿瘤，虽然它们的存在与疾病预后不良相关，但仍有待进一步研究 确定什么触发并控制它们的分化。使用小鼠自发模型 乳腺癌与人类疾病密切相关，我们最近证明 TAM 源自单核细胞，它们的分化依赖于Notch信号传导，并且在没有Notch信号传导的情况下， 肿瘤生长减慢，肿瘤中的 T 细胞表达更多的效应分子和更少的效应分子 衰竭标记物，表明 TAM 具有免疫抑制作用。我提议的工作旨在 进一步探讨TAM在肿瘤微环境中的分化程序和功能。我的 初步结果表明 TAM 特异性表达高水平的转录因子 干扰素调节因子 8 (IRF8)，如果没有 IRF8，TAM 分化就会被阻断。 IRF8 已知是其他骨髓细胞群的关键谱系决定因素，并且可以介导 与抗原呈递相关的基因表达，从而影响 T 细胞反应。在这个 提案，我的目标是使用小鼠来描述 IRF8 如何介导 TAM 分化和功能 遗传学和小鼠疾病模型。我将确定哪些外部线索驱动 IRF8 表达 以及 IRF8 使用全基因组染色质在 TAM 中控制哪些遗传程序 免疫沉淀测序 (ChIP-seq) 和 RNA 测序。通过功能丧失研究 和离体细胞培养测定，我的工作将直接测量潜在的 IRF8 介导的 TAM 对肿瘤微环境中 T 细胞和其他免疫细胞的免疫抑制活性。的 概述的提案，使用明确的方法，将产生结论性的、有意义的数据，并将 拓宽我们对 TAM 功能和身份的理解。我的发现可能会揭示新的途径 癌症免疫疗法可操纵 TAM，增强内源性抗肿瘤反应， 为抗击癌症提供重要的新工具。

PROJECT SUMMARY/ABSTRACT Tumor-associated macrophages (TAMs) are often the dominant immune cell type found in solid human tumors, and while their presence is correlated with poor disease prognosis, it remains to be determined what triggers and controls their differentiation. Using a murine model of spontaneous breast cancer that closely recapitulates human disease, we have recently demonstrated that TAMs are derived from monocytes, their differentiation relies on Notch signaling, and in their absence, tumor growth is slowed and T cells in the tumor express more effector molecules and fewer exhaustion markers, suggesting an immunosuppressive role for TAMs. My proposed work aims to further explore the differentiation program and function of TAMs in the tumor microenvironment. My preliminary findings demonstrate that TAMs specifically express high levels of the transcription factor interferon regulatory factor 8 (IRF8), and in the absence of IRF8, TAM differentiation is blocked. IRF8 is known to be a key lineage-determining factor for other myeloid cell populations and can mediate expression of genes related to antigen-presentation, thus influencing T cell responses. In this proposal, I aim to characterize how IRF8 mediates TAM differentiation and function using mouse genetics and mouse models of disease. I will determine what external cues drive IRF8 expression and what genetic programs IRF8 controls in TAMs using genome-wide chromatin immunoprecipitation sequencing (ChIP-seq) and RNA-sequencing. Through loss-of-function studies and ex vivo cell culture assays, my work will directly measure the potential IRF8-mediated TAM immunosuppressive activities on T cells and other immune cells in the tumor microenvironment. The outlined proposal, using definitive approaches, will generate conclusive, meaningful data and will broaden our understanding of TAM function and identity. My findings may uncover novel avenues for cancer immunotherapies to manipulate TAMs, boosting endogenous anti-tumor responses and providing critical new tools in the fight against cancer.