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

项目总结/摘要 肿瘤相关巨噬细胞（TAM）通常是实体瘤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。 决定了什么触发和控制它们的分化。使用自发的小鼠模型， 乳腺癌，密切重演人类疾病，我们最近已经证明， 来源于单核细胞，它们的分化依赖于Notch信号传导，并且在它们不存在的情况下， 肿瘤生长减慢，肿瘤中的T细胞表达更多的效应分子， 耗尽标志物，表明TAM的免疫抑制作用。我的工作目标是 进一步探讨TAM在肿瘤微环境中的分化程序和功能。我 初步发现表明TAM特异性表达高水平的转录因子 干扰素调节因子8（IRF 8），并且在IRF 8不存在的情况下，TAM分化被阻断。IRF8 已知是其他髓系细胞群体的关键谱系决定因子， 与抗原呈递相关的基因的表达，从而影响T细胞应答。在这 因此，我的目标是利用小鼠模型来表征IRF 8是如何介导TAM分化和功能的。 遗传学和疾病的小鼠模型。我将确定什么外部线索驱动IRF 8表达 以及IRF 8利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 和离体细胞培养试验，我的工作将直接测量潜在的IRF 8介导的TAM 在肿瘤微环境中对T细胞和其他免疫细胞的免疫抑制活性。的 概述的建议，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功能和特性的理解。我的发现可能会为 癌症免疫疗法来操纵TAM，增强内源性抗肿瘤反应， 为对抗癌症提供了重要的新工具。

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.