Crosstalk between CES1 and PPAR gamma and LXR alpha in macrophages

摘要 生物活性脂质和炎症的交集是免疫细胞在组织损伤过程中的一个中心特征， 尤其是巨噬细胞。当体内平衡机制不能解决炎症反应和/或 变得适应不良，慢性低度炎症状况或过度伤口愈合事件 已经成立了。例如，肺纤维化和动脉粥样硬化，部分是由于过度活跃的组织修复和 分别为炎症消退缺陷。对于这些问题的性质，存在着重大的知识空白 脂质相互作用体在健康和疾病中的作用，以及它如何调节炎症以加剧组织损伤 或促进解决/修复。因此，“炎症消解程序中的缺陷”是一个主要的主题 通过这个提议。这项资助的具体目标是机械地理解免疫调节。 我们观察到代谢性丝氨酸水解酶-人羧酸酯酶-1之间的串扰 (CES1)-以及影响巨噬细胞表型的脂质敏感核受体PPARGamma和LXRpha 在暴露于细胞因子和氧化型低密度脂蛋白等“危险相关分子”后功能正常 脂蛋白(OxLDL)。为了解决这个问题，我们假设CES1在巨噬细胞中的一个功能是 调节PPARGamma和LXRpha在分辨率设置中感受到的内源性配体水平 炎症，从而调节这些假定的抗炎受体的活性。这将通过以下方式进行测试 两个目标将：(I)表征CES1和脂质感受器PPARγ和PPAR之间的串扰 LXRpha；(Ii)评价小鼠Ces1d(人CES1的小鼠同源基因)在肺中的作用机制 调节肺纤维化模型中“交替极化”的巨噬细胞的活动。人类单核细胞- 带有关键基因敲除的衍生巨噬细胞和创新的小鼠模型将被用于研究 巨噬细胞激活刺激对生化、基因组和脂类产出的影响。这件事的影响 该项目将演示CES1如何传递形成免疫表型的细胞外信号 巨噬细胞。在这个阶段，CES1和核受体PPARGamma和LXRpha之间的联系是 不清楚；然而，获得这些知识将允许新的和创新的方法来在治疗上缓和 M1和M2巨噬细胞的活性分别加剧了动脉粥样硬化和肺纤维化。跟随 这个项目的成功完成，我们将更好地了解CES1的监管机制 细胞水平的氧化化学物质(氧化脂类和氧化甾醇)是在脂质和 由化学物质引起的炎症。此外，我们将更好地了解这些因素随后的相互作用 巨噬细胞中与蛋白质(例如，配体激活的转录因子)的化合物最终形成 他们在健康和伤害中对免疫极化刺激的细胞反应。

Abstract The intersection of bioactive lipids and inflammation is a central feature of immune cells during tissue injury, particularly in macrophages. When homeostatic mechanisms fail to resolve inflammatory responses and/or become maladaptive, chronic low-grade inflammatory conditions or excessive wound healing events can be established. For example, lung fibrosis and atherosclerosis, in part, results from overactive tissue repair and defective inflammation resolution, respectively. There are major knowledge gaps regarding the nature of the lipid interactome in health and disease, and how it modulates inflammation to either exacerbate tissue damage or promote resolution/repair. Thus, ‘defects in inflammation resolution programs’ is a major theme that runs through this proposal. The specific goal of this grant is to mechanistically understand the immunoregulatory crosstalk we have observed between a metabolic serine hydrolase – termed human carboxylesterase 1 (CES1) – and the lipid-sensing nuclear receptors PPARgamma and LXRalpha, which can affect macrophage phenotype and function after exposure to ‘danger-associated molecules’, such as cytokines and oxidized low-density lipoproteins (oxLDL). To attack this problem, we hypothesize that one function of CES1 in macrophages is to regulate the levels of endogenous ligands that are sensed by PPARgamma and LXRalpha in the setting of resolving inflammation, thus modulating the activity of these putative anti-inflammatory receptors. This will be tested with two aims that will: (i) Characterize the cross talk between CES1 and the lipid-sensing receptors PPARgamma and LXRalpha; (ii) Evaluate the mechanisms by which murine Ces1d (the mouse ortholog of human CES1) in lung regulates the activity of ‘alternatively polarized’ macrophages in a pulmonary fibrosis model. Human monocyte- derived macrophages with key genes knocked out and an innovative mouse model will be used to study the effects of macrophage-activating stimuli on biochemical, genomic, and lipidomic outputs. The impact of this project is that it will demonstrate how CES1 transduces extracellular signals that shape the immunophenotype of macrophages. At this stage, the links between CES1 and the nuclear receptors PPARgamma and LXRalpha are unclear; however, obtaining this knowledge would allow new and innovative ways to therapeutically temper the activities of M1 and M2 macrophages that exacerbate atherosclerosis and lung fibrosis, respectively. Following the successful completion of this project, we will better understand the mechanisms by which CES1 regulates cellular levels of oxidized chemicals (oxylipins and oxysterols) that are formed in the context of lipid- and chemical-driven inflammation. Further, we will have a better view of the subsequent interactions of these compounds with proteins (e.g., ligand-activated transcription factors) in macrophages that ultimately shape their cellular response to immune-polarizing stimuli in health and injury.