Role of choline metabolism in activated macrophage phenotypes

PRO项目总结 巨噬细胞(MO)在许多疾病的炎症传播中起着至关重要的作用。最近的工作有 风湿性疾病滑膜组织中功能分子的异质性突出。激活的MO的存在 而滑膜中促炎和抗炎MO种群的失衡与 对疾病进展和临床表现的影响。在其他刺激中，关节中的MO是由损伤激活的 相关分子模式(DAMP)，由NLRP3炎症体感知并激活IL-1和IL-18- 一种依赖性炎症，使关节细胞从静止的调节状态转变为高度代谢活跃的状态。 胆碱代谢异常正在成为细胞活化和炎症的代谢标志。胆碱 是一种类似维生素的必需营养素，被胆碱激酶α(CHOK)磷酸化，作为新生的 合成卵磷脂(PC)。新出现的脂肪组学研究表明，一些风湿性疾病表现出 滑液中胆碱循环水平的增加和磷脂(PL)的变化。此外, 滑膜MO表达胆碱转运体，提示胆碱代谢在滑膜MO激活中起作用。 PI之前的工作已经确立了维生素类营养物质胆碱摄取和 IL-1和IL-18对PC合成和NLRP3炎症体依赖性产生的动员作用 启用生产任务单。Chok抑制胆碱摄取或磷酸化改变线粒体磷脂含量和 降低了细胞内的三磷酸腺苷，这导致了有丝分裂的启动，阻止了线粒体DNA的氧化， 最终阻止NLRP3炎症体的激活和IL-1、IL-18的产生。此外, ChOK抑制可减少痛风和Muckle Wells综合征小鼠模型的炎症。 PI现在提供了初步数据，表明MO中胆碱的利用调节MO生物学，包括 钼偏振。她还描述了内毒素诱导的MO激活伴随着代谢和PL 依赖于胆碱供应的重组变化。此外，她还展示了关于 Chok在骨性关节炎中的作用。这些发现表明了一个有吸引力的假设，即营养代谢可以 在风湿性疾病背景下调节滑膜激活的MO表型。 目前的提案将对胆碱代谢和PL组成的作用提供一个全面的展望 在MO激活和生物学中，通过三个特定的目的。AIM 1将评估MO的胆碱代谢 分化和极化；目标2将探索胆碱可获得性对其相关代谢的作用 和生物能量变化；Aim 3将研究胆碱在OA滑膜中的可获得性及其磷酸化。 拟议的研究和培训计划将有助于PI向独立调查员过渡，并将提供 她在免疫代谢、翻译研究、代谢组学和线粒体生物能量学方面拥有专业知识。 这项工作将在髓系生物学专家迈克尔·卡林博士和莫妮卡博士的指导下进行 关节炎研究方面的专家Guma，以及来自一流咨询委员会的指导。

PRO PROJECT SUMMARY Macrophages (MO) play a crucial role in the propagation of inflammation in many diseases. Recent work has highlighted functional MO heterogeneity in synovial tissue of rheumatic diseases. The presence of activated MO and the imbalance of pro-inflammatory and anti-inflammatory MO populations in the synovium has been related to disease progression and clinical manifestations. Among other stimuli, MO in the joints are activated by damage associated molecular patterns (DAMP), that are sensed by NLRP3 inflammasome and activate IL-1 and IL-18- dependent inflammation that shifts joint cells from a resting regulatory state to a highly metabolically active one. Abnormal choline metabolism is emerging as a metabolic hallmark of cell activation and inflammation. Choline is a vitamin-like essential nutrient that is phosphorylated by choline kinase alpha (ChoK) as precursor to newly synthesized phosphatidylcholine (PC). Emerging lipidomic studies indicate that some rheumatic diseases exhibit an increase of choline circulating levels and an altered phospholipid (PL) profile in the synovial fluid. In addition, synovial MO express choline transporters, suggesting a role of choline metabolism in synovial MO activation. Previous work by the PI has established an essential role for the vitamin-like nutrient choline uptake and mobilization towards PC synthesis and NLRP3 inflammasome-dependent production of IL-1 and IL-18 in activated MO. Inhibition of choline uptake or phosphorylation by ChoK altered mitochondrial PL content and reduced cellular ATP, which resulted in the initiation of mitophagy, prevention of mitochondrial DNA oxidation, and ultimately, prevention of activation of NLRP3 inflammasome and production of IL-1 and IL-18. In addition, ChoK inhibition decreased inflammation in murine models of gout and Muckle Wells syndrome. The PI now provides preliminary data suggesting that choline utilization in MO modulates MO biology including MO polarization. She also describes that LPS-induced MO activation is accompanied by metabolic and PL reorganization changes that are dependent on choline availability. Additionally, she shows novel data about the role of ChoK in osteoarthritis. These findings suggest the attractive hypothesis that nutrient metabolism could modulate synovial activated MO phenotypes in the context of rheumatic diseases. The current proposal will provide a comprehensive vision of the role of choline metabolism and PL composition in MO activation and biology, through three Specific Aims. Aim 1 will evaluate choline metabolism in MO differentiation and polarization; Aim 2 will explore the role of choline availability on their associated metabolic and bioenergetic changes; Aim 3 will investigate choline availability and its phosphorylation in the OA synovium. The proposed studies and training plan will help PI’s transition to an independent investigator and will provide her with expertise in immunometabolism, translational research, metabolomics, and mitochondrial bioenergetics. The work will be performed with the mentorship of Dr. Michael Karin, an expert in myeloid biology, and Dr. Monica Guma, an expert in arthritis research, as well as guidance from a stellar Advisory Committee.