Regulation of brown fat metabolism by the immune receptor PD-L1

第7节：项目摘要/摘要 包括肥胖和II型糖尿病在内的代谢性疾病现在是全球关注的健康问题， 流行率。产生热量的棕色和米色脂肪已被建议作为治疗新疗法的靶点。 基于动物模型的代谢性疾病，已表明这些组织在两者的易感性中起作用 糖尿病的肥胖症。我们有挑衅性的初步数据显示免疫调节的表达 小鼠棕色脂肪中的蛋白质程序性死亡配体1(PD-L1)。我们发现帕金森病的功能丧失- L1导致调节脂肪代谢和棕色脂肪内线粒体生物生成的基因发生变化，以及 这些变化与核心体温升高和意外增加的风险有关 当小鼠接触到高脂肪食物时，体重增加。PD-L1作为一种新的肿瘤标志物，在临床上受到广泛关注。 肿瘤逃避宿主免疫的中心成分；使用阻断PD的抗体进行免疫治疗- L1或其受体程序性死亡1(PD-1)被临床用于治疗黑色素瘤、肺癌和膀胱癌。 PD-1/PD-L1通路与肿瘤和免疫细胞的代谢变化有关 对它们做出反应，打开了针对这一途径的治疗可能直接影响 这些细胞的生长和复制。因此，对PD-L1对新陈代谢的调节有更深的理解 有很大的临床价值。我们假设PD-L1直接调节棕色脂肪的功能，改变 产生热量和降低肥胖风险。进一步了解PD-L1在棕色脂肪中的作用 显然，我们首先提出了一种新的小鼠品系，该品系的小鼠在棕色脂肪中特异性地去除了PD-L1 作为先前的实验，细胞本身已经完成了PD-L1缺乏症在整个小鼠中的均匀分布。 这些棕色脂肪特异的PD-L1缺陷动物是必要的，以明确地证明 PD-L1参与棕色脂肪代谢。同样，我们将产生PD-L1细胞内尾巴的小鼠 仅在棕色脂肪中去除；这些动物将使我们能够寻找直接的PD-L1信号在调节 棕色脂肪。我们将检查这些新的小鼠品系对肥胖的易感性和产热能力；我们 还将使用更复杂的能量消耗和进食跟踪来了解驱动力 在这些动物肥胖风险上升的背后。这个项目的第二个目标是描述 PD-L1缺陷性棕色脂肪蛋白质表达和代谢中间产物的变化 PD-L1调节棕色脂肪的分子机制。这些实验将使用免疫印迹和 基于LC/MS的代谢组学研究整体PD-L1缺陷小鼠的棕色脂肪，以及新的 在这个项目中产生了棕色脂肪特异性PD-L1缺陷小鼠。这个项目的长期目标是 阐明PD-L1在调节代谢性疾病中的作用，这应该没有意义 仅用于调节体重，但也有可能用于癌症免疫治疗。

Section 7: Project Summary/Abstract Metabolic diseases including obesity and type II diabetes are now global health concerns with a rising prevalence. Heat producing brown and beige fat have been proposed as targets for novel therapies to treat metabolic diseases based on animal models that have shown a role for these tissues in susceptibility to both obesity of diabetes. We have provocative preliminary data that show expression of the immune regulatory protein programmed death ligand 1 (PD-L1) within the brown fat of mice. We found that loss of function of PD- L1 led to changes in genes that regulate fat metabolism and mitochondrial biogenesis within the brown fat, and that these changes were associated with increased core body temperature and a surprising increased risk of weight gain when the mice were exposed to a high-fat diet. PD-L1 has achieved much clinical attention as a central component in enabling tumors to evade host immunity; immune therapy using antibodies that block PD- L1 or its receptor programmed death 1 (PD-1) are in clinical use to treat melanoma, lung and bladder cancer. The PD-1/PD-L1 pathway has been linked to metabolic changes in both tumors and the immune cells that respond to them, opening up the possibility that therapies targeting this pathway may directly influence the growth and replication of these cells. Thus a deeper understanding of the regulation of metabolism by PD-L1 is of substantial clinical interest. We hypothesize that PD-L1 directly regulates brown fat function, altering heat generation and modifying the risk of obesity. To understand the role of PD-L1 in brown fat more clearly, we propose first to generate a novel strain of mice with PD-L1 specifically removed in the brown fat cells themselves as prior experiments have been done with PD-L1 deficiency uniform across the whole mouse. These brown fat specific PD-L1 deficient animals are necessary to unequivocally demonstrate a direct role for PD-L1 in brown fat metabolism. Similarly, we will generate mice where the intracellular tail of PD-L1 has been removed only in brown fat; these animals will enable us to look for direct PD-L1 signaling in the regulation of brown fat. We will examine both susceptibility to obesity, and heat generation in these novel mouse strains; we will also use more sophisticated tracking of energy expenditure and feeding to understand the driving forces behind the elevated obesity risk in these animals. The second goal of this project is to characterize the changes in protein expression and metabolic intermediates in PD-L1 deficient brown fat to uncover the molecular mechanism by which PD-L1 regulates brown fat. These experiments will use immunoblotting and LC/MS based metabolomics to look at brown fat from total body PD-L1 deficient mice, as well as the novel brown fat specific PD-L1 deficient mice generated in this project. The long-term goal of this project is to elucidate the function of PD-L1 in regulation of metabolic disease, which should have implications not only for the regulation of body weight, but potentially for cancer immunotherapy as well.