Signal Transduction of Paired Inhibitory Receptors of NK Cells and Macrophages

实验室一直在采取一种方法，更多地考虑代谢生态位内部的相互作用和适应。我们假设免疫细胞的代谢适应导致其环境的改变。因此，被免疫细胞浸润的肿瘤将有不同的代谢燃料的可用性，这将推动肿瘤在生长过程中的适应，反之亦然。我们最近发现腹膜腔是一个独特的代谢生态位。结合详细的生化分析、代谢组学、特异性抑制剂、通量分析和NCI-Frederick光学显微镜分析实验室的高清显微镜，我们发现腹膜常驻巨噬细胞（pRes）利用了效应功能的利基。腹膜生态位中的这种共生生化相互作用使我们研究了腹膜中对癌症可能的代谢适应。简而言之，我们发现氯膦酸钠消耗pRes可重复地减少腹膜中的肿瘤负荷。代谢评估显示，来自腹膜荷瘤小鼠的pRes具有更高水平的脂肪酸驱动的氧消耗，以及由免疫应答基因-1 （Irg1）酶产生的衣康酸积累。值得注意的是，仅在pRes中特异性敲除Irg1就足以消除它们的促肿瘤作用。我们对这种活性进行了机制剖析，发现Irg1的表达促进了脂肪酸的氧化磷酸化，导致ROS的形成，进而激活肿瘤细胞中的pErk。我们的数据表明，腹膜中的肿瘤生态位引发Irg1，导致代谢重编程进入肿瘤促进状态。我们对生态位特异性癌症相关代谢适应的鉴定促使我们寻找白细胞的癌症生态位适应。我们发现了一个依赖于ckit的中性粒细胞亚群，它们具有更高水平的线粒体功能，并且即使在葡萄糖利用有限的情况下也具有产生大量氧化爆发的独特能力。乳腺癌相关（4T1）中性粒细胞具有这些相同的特征。我们将这些特征映射到利用脂肪酸生成NADPH的能力，而NADPH反过来又为Nox2提供燃料。重要的是，癌症患者的外周血也显示出具有不成熟表型的中性粒细胞数量增加，线粒体含量高于对照组，并且氧气消耗水平更高。最近，我们使用寄生虫感染和内源性休克模型证实，分别由il - 4或一氧化氮驱动的特异性代谢重编程导致整个腹膜生态位的重大改变。这些发现证实了我们的假设，揭示了免疫细胞代谢编程可以通过控制周围细胞的代谢燃料来产生广泛的生理效应。

The laboratory has been taking an approach that involves more consideration of the interactions within, and adaptations to, metabolic niches. We hypothesize that metabolic adaptation of immune cells results in modification of their environment. As a consequence, tumors infiltrated with immune cells will have different availability of metabolic fuels that will drive adaptation of tumors during growth and vice versa. We recently found that the peritoneal cavity is a unique metabolic niche. Using a combination of detailed biochemical analysis, metabolomics, specific inhibitors, flux analysis, and high definition microscopy with the NCI-Frederick Optical Microscopy Analysis Laboratory we found that peritoneal resident macrophages (pRes) exploit that niche for effector function. This symbiotic biochemical interaction in the peritoneal niche led us to examine possible metabolic adaptation to cancer in the peritoneum. In brief, we found that clodronate depletion of pRes reproducibly reduced tumor burden in the peritoneum. Metabolic assessment showed that pRes from peritoneal tumor-bearing mice had higher levels of fatty acid driven oxygen consumption, and accumulated itaconic acid produced by the enzyme Immunoresponsive Gene-1 (Irg1). Remarkably, specific knockdown of Irg1 only in pRes, was sufficient to ablate their pro-tumor effects. We mechanistically dissected this activity and found that Irg1 expression facilitated oxidative phosphorylation of fatty acids resulting in ROS formation which in turn activates pErk in tumor cells. Our data suggest that the tumor niche in the peritoneum elicits Irg1 resulting in metabolic reprogramming into a tumor promotion state. Our identification of niche specific cancer-associated metabolic adaptations prompted us to look for cancer niche adaptations of leukocytes. We uncovered a subpopulation of cKit-dependent neutrophils with higher levels of mitochondrial function and the unique ability to generate substantial oxidative burst even when glucose utilization was limited. Breast cancer-associated (4T1) neutrophils have these same characteristics. We mapped these characteristics to the ability to utilize fatty acids for the generation of NADPH, that in turn fuels Nox2. Importantly, the peripheral blood of cancer patients also showed increased numbers of neutrophils with an immature phenotype that were higher in mitochondrial content than controls, and had higher levels of oxygen consumption. Most recently, we have confirmed using model of parasitic infection and endotoxic shock, that specific metabolic reprogramming driven by IL4 or nitric oxide, respectively, results in substantial modification of the overall peritoneal niche. These findings, confirm our hypothesis by revealing that immune cell metabolic programming can have wide ranging physiologic effects by controlling the metabolic fuels available to surrounding cells.