The role of MIF in mitochondrial metabolism and M2-TAM polarization

项目总结/摘要 “The role of MIF in mitochondrial metabolism and M2-TAM polarization.” 肿瘤相关巨噬细胞（TAM）促进肿瘤内微血管密度，增加肿瘤 基质基质重塑和有效抑制晚期癌症患者抗肿瘤免疫。虽然 大量的研究已经确定了“M2”TAM极化如何促进肿瘤进展，但知之甚少 关于TAM如何在肿瘤微环境中获得这种M2表型。代谢重编程是一种 巨噬细胞极化的关键决定因素，因为最近的研究表明，M2 TAM采用氧化 磷酸化/线粒体代谢表型，并独特地响应于肿瘤内的代谢物 微环境这项提案的长期目标是研究巨噬细胞 迁移抑制因子（MIF）决定乳酸盐增强的M2极化。我们的初步研究表明 M2巨噬细胞将细胞外乳酸代谢为丙酮酸，丙酮酸又在线粒体中被氧化 并且对于显著增强Th 2肾上腺素依赖性M2 TAM极化是必要且充分的。 我们的数据进一步表明，MIF促进线粒体代谢，这是最大的 乳酸盐/琥珀酸盐增强的M2极化和促肿瘤发生表型的获得。两个目标是 具体目标1：描述乳酸/丙酮酸的机制效应物， HIF 1 α依赖性M2-巨噬细胞极化。目的：使用代谢通量分析的组合， 代谢组学、基因表达测定、转基因小鼠和机制研究，以回答三个主要问题， 问题：1）M2巨噬细胞是否积极代谢乳酸; 2）利用哪些代谢途径 实现这一点，以及; 3）乳酸代谢如何在机制上与M2极化相关具体目标2： 确定MIF在乳酸/戊酸介导的M2 TAM极化中的机制贡献。 目的：利用突变MIF蛋白的再表达、小分子拯救研究、流式细胞术和基因 1）MIF是否支配线粒体生物发生， M2巨噬细胞的代谢; 2）MIF是否以及如何通过与M2巨噬细胞结合来影响线粒体代谢。 CSN 5和调节NRF 2稳定性，以及; 3）如果MIF在功能上与乳酸盐扩增的HIF 1 α稳定性相关， M2极化。

PROJECT SUMMARY/ABSTRACT “The role of MIF in mitochondrial metabolism and M2-TAM polarization.” Tumor-associated macrophages (TAMs) promote intratumoral microvessel density, increase tumor stromal matrix remodeling and potently suppress anti-tumor immunity in late-stage cancer patients. Although substantial research has identified how “M2” TAM polarization promotes tumor progression, much less is known about how TAMs obtain this M2 phenotype within tumor microenvironments. Metabolic reprogramming is a critical determinant of macrophage polarization as recent studies demonstrate that M2 TAMs adopt an oxidative phosphorylation/mitochondrial metabolic phenotype and uniquely respond to metabolites within the tumor microenvironment. This proposal’s long-term objective is to investigate the mechanisms by which macrophage migration inhibitory factor (MIF) dictates lactate-enhanced M2 polarization. Our preliminary studies demonstrate that M2 macrophages metabolize extracellular lactate to pyruvate which, in turn, is oxidized in the mitochondria and is both necessary and sufficient to significantly enhancing Th2 cytokine-dependent M2 TAM polarization. Our data further indicates that MIF promotes mitochondrial metabolism which is required for maximal lactate/pyruvate-enhanced M2 polarization and acquisition of pro-tumorigenic phenotypes. Two aims are proposed to test our hypotheses: Specific Aim 1: Delineate the mechanistic effectors of lactate/pyruvate to HIF1α-dependent M2-macrophage polarization. Objective: To use a combination of metabolic flux analyses, metabolomics, gene expression assays, transgenic mice and mechanistic studies to answer three primary questions: 1) Whether M2 macrophages actively metabolize lactate; 2) Which metabolic pathways are utilized to accomplish this, and; 3) How is lactate metabolism mechanistically linked to M2 polarization Specific Aim 2: Determine the mechanistic contributions of MIF in lactate/pyruvate-mediated M2 TAM polarization. Objective: Use mutant MIF protein re-expression, small-molecule rescue studies, flow cytometry and gene expression assays to make three determinations: 1) Whether MIF dictates mitochondrial biogenesis and metabolism in M2 macrophages; 2) Whether and how MIF influence mitochondrial metabolism by binding to CSN5 and regulating NRF2 stability, and; 3) If MIF is functionally linked to lactate-amplified HIF1α stability and ensuing M2 polarization.