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

第7节：项目总结/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健康问题， 普遍性。产热棕色和米色脂肪已被提议作为新疗法的靶点，以治疗 基于动物模型的代谢性疾病，这些模型显示这些组织在对两种疾病的易感性中的作用， 糖尿病的肥胖。我们有挑衅性的初步数据表明，表达的免疫调节 蛋白程序性死亡配体1（PD-L1）在小鼠的棕色脂肪。我们发现PD功能的丧失- L1导致调节棕色脂肪内脂肪代谢和线粒体生物合成的基因发生变化， 这些变化与核心体温的升高和患上癌症的风险惊人地增加有关。 当老鼠被暴露在高脂肪饮食中时，体重增加。PD-L1作为一种 使肿瘤能够逃避宿主免疫的核心成分;使用阻断PD的抗体的免疫治疗- L1或其受体程序性死亡1（PD-1）在临床上用于治疗黑色素瘤、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， 对它们作出反应，开辟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，更深入地了解PD-L1对代谢的调节， 具有重要的临床意义。我们假设PD-L1直接调节棕色脂肪功能，改变 产生热量和改变肥胖的风险。了解PD-L1在棕色脂肪中的作用 显然，我们建议首先产生一种新的小鼠品系，在棕色脂肪中特异性去除PD-L1， 细胞本身，因为先前的实验已经在整个小鼠中均匀地进行了PD-L1缺乏。 这些棕色脂肪特异性PD-L1缺陷动物是明确证明PD-L1在细胞内的直接作用所必需的。 PD-L1在棕色脂肪代谢中的作用类似地，我们将产生PD-L1的细胞内尾已经被 这些动物将使我们能够寻找PD-L1信号的直接调节， 棕色脂肪我们将研究这些新型小鼠品系对肥胖的易感性和产热情况; 还将使用更复杂的能量消耗和喂养跟踪来了解驱动力 这些动物肥胖风险升高的背后。该项目的第二个目标是描述 PD-L1缺乏棕色脂肪中蛋白质表达和代谢中间体的变化，以揭示 PD-L1调节棕色脂肪的分子机制。这些实验将使用免疫印迹， 基于LC/MS的代谢组学研究来自全身PD-L1缺陷小鼠的棕色脂肪，以及新的 棕色脂肪特异性PD-L1缺陷小鼠。该项目的长期目标是 阐明PD-L1在调节代谢疾病中的功能，这应该不会对 不仅用于调节体重，而且还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.