Metabolic Reprogramming of Mouse Bone Marrow Derived Macrophages Following Erythrophagocytosis
Metabolic Reprogramming of Mouse Bone Marrow Derived Macrophages Following Erythrophagocytosis
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小鼠骨髓巨噬细胞吞噬红细胞后的代谢重编程
DOI：
10.3389/fphys.2020.00396
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发表时间：
2020-04-30
影响因子：
4
通讯作者：
D'Alessandro, Angelo
中科院分区：
文献类型：
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作者：
Catala, Alexis;Youssef, Lyla A.;D'Alessandro, Angelo
网状内皮巨噬细胞在称为红细胞吞噬作用（EP）的过程中每天吞噬约0.2万亿个衰老红细胞。这一关键机制通过调节红细胞分解代谢和铁循环来维持全身血红素-铁稳态。虽然大量的工作已经证明了促炎细胞因子刺激对巨噬细胞代谢重编程的各种影响，但对EP对巨噬细胞代谢组和蛋白质组的影响知之甚少。因此，我们对小鼠骨髓源性巨噬细胞（bmdm）在igg包被红细胞EP前后进行了基于质谱的代谢组学和蛋白质组学分析。此外，对与游离IgG孵育的bmdm进行代谢组学研究，以确保巨噬细胞代谢的变化是由于活化的红细胞而不是游离IgG结合。在存在和不存在igg包被红细胞的情况下，对BMDMs进行均匀标记示踪实验，以评估葡萄糖通过戊糖磷酸途径（PPP）的通量。在这项研究中，我们证明了EP显著改变氨基酸和脂肪酸代谢、克雷布斯循环、氧化磷和花生四烯酸酯-亚油酸代谢。在EP后的bmdm中，氨基酸、脂质和氧化脂质、血红素产物和红细胞衍生蛋白的水平升高。U-C-13(6)葡萄糖示踪实验表明，通过糖酵解的通量减慢，PPP激活增强。值得注意的是，我们发现它是由巨噬细胞本身或EP前的细胞外介质产生的葡萄糖驱动的，而不是来自调理的红细胞。然后，ppp衍生的NADPH可以促进氧化爆发，导致活性氧的产生，通过自由基攻击促进被吞噬的RBC蛋白的消化。氧化还原蛋白质组学实验证实，Cys152和Cys94分别氧化甘油醛3-磷酸脱氢酶（GAPDH）和血红蛋白- β。早期Krebs循环和c -5支化二酸代谢物（分别为α -酮戊二酸和2-羟基戊二酸）的显著增加表明EP促进线粒体代谢失调。最后，EP刺激了氨基乙酰丙酸（ALA）合成酶和精氨酸酶的活性，这表明在igg介导的红细胞摄入后ALA和鸟氨酸的显著积累。重要的是，ep介导的BMDMs代谢重编程不会在单独暴露于IgG后发生。综上所述，我们发现EP重编程巨噬细胞代谢并改变巨噬细胞极化。
Reticuloendothelial macrophages engulf similar to 0.2 trillion senescent erythrocytes daily in a process called erythrophagocytosis (EP). This critical mechanism preserves systemic heme-iron homeostasis by regulating red blood cell (RBC) catabolism and iron recycling. Although extensive work has demonstrated the various effects on macrophage metabolic reprogramming by stimulation with proinflammatory cytokines, little is known about the impact of EP on the macrophage metabolome and proteome. Thus, we performed mass spectrometry-based metabolomics and proteomics analyses of mouse bone marrow-derived macrophages (BMDMs) before and after EP of IgG-coated RBCs. Further, metabolomics was performed on BMDMs incubated with free IgG to ensure that changes to macrophage metabolism were due to opsonized RBCs and not to free IgG binding. Uniformly labeled tracing experiments were conducted on BMDMs in the presence and absence of IgG-coated RBCs to assess the flux of glucose through the pentose phosphate pathway (PPP). In this study, we demonstrate that EP significantly alters amino acid and fatty acid metabolism, the Krebs cycle, OXPHOS, and arachidonate-linoleate metabolism. Increases in levels of amino acids, lipids and oxylipins, heme products, and RBC-derived proteins are noted in BMDMs following EP. Tracing experiments with U-C-13(6) glucose indicated a slower flux through glycolysis and enhanced PPP activation. Notably, we show that it is fueled by glucose derived from the macrophages themselves or from the extracellular media prior to EP, but not from opsonized RBCs. The PPP-derived NADPH can then fuel the oxidative burst, leading to the generation of reactive oxygen species necessary to promote digestion of phagocytosed RBC proteins via radical attack. Results were confirmed by redox proteomics experiments, demonstrating the oxidation of Cys152 and Cys94 of glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and hemoglobin-beta, respectively. Significant increases in early Krebs cycle and C-5-branched dibasic acid metabolites (alpha-ketoglutarate and 2-hydroxyglutarate, respectively) indicate that EP promotes the dysregulation of mitochondrial metabolism. Lastly, EP stimulated aminolevulinic acid (ALA) synthase and arginase activity as indicated by significant accumulations of ALA and ornithine after IgG-mediated RBC ingestion. Importantly, EP-mediated metabolic reprogramming of BMDMs does not occur following exposure to IgG alone. In conclusion, we show that EP reprograms macrophage metabolism and modifies macrophage polarization.