【作者】 李泽宇；

【导师】 曾天舒；

【作者基本信息】 华中科技大学 ， 内科学（内分泌与代谢病）， 2023， 博士

【摘要】 目的:代谢性炎症促进了肥胖相关并发症的发生发展。巨噬细胞炎性活化是代谢性炎症的关键环节。衣康酸作为巨噬细胞免疫调节剂,在多种炎症性疾病中表现出良好的治疗潜力。本课题将研究衣康酸在代谢性炎症中的作用。方法:1、构建衣康酸缺乏的IRG1-/-小鼠,以高脂饮食喂养野生型(wild type,WT)和IRG1-/-小鼠诱导肥胖模型,研究衣康酸缺乏对于肥胖代谢性炎症的影响。实验分组为:WT正常饮食组、IRG1-/-正常饮食组、WT高脂饮食组、IRG1-/-高脂饮食组。检测小鼠糖脂代谢情况及循环、肝脏、脂肪组织和骨髓来源巨噬细胞(Bone marrow derived macrophage,BMDM)炎症水平。2、体外使用棕榈酸(palmitic acid,PA)诱导巨噬细胞炎症反应,研究衣康酸衍生物4-OI调控巨噬细胞炎症的分子机制。3、探索4-OI治疗对肥胖代谢性炎症的影响。实验分组为:正常饮食组、高脂饮食组、高脂饮食+4-OI组。检测小鼠糖脂代谢情况及循环、肝脏、脂肪组织和BMDM炎症水平。结果:1、与WT小鼠相比,IRG1-/-小鼠在高脂饮食喂养下体重、肝脏重量和脂肪组织含量更高。IRG1-/-小鼠在肥胖期间血糖和血脂水平升高,糖脂代谢紊乱更加严重。IRG1-/-小鼠循环、肝脏和脂肪组织炎症因子IL-1β、IL-18水平升高更为显著,NLRP3炎症小体激活增加。IRG1-/-小鼠BMDM在体外LPS诱导下炎症因子水平和NLRP3炎症小体激活增加。2、衣康酸衍生物4-OI抑制了PA诱导的RAW 264.7巨噬细胞炎症因子IL-1β、IL-18水平和NLRP3炎症小体激活;4-OI抑制了PA诱导的巨噬细胞活性氧(reactive oxygen species,ROS)生成,同时ROS抑制剂NAC对NLRP3炎症小体表现出与4-OI相当的抑制作用。4-OI能够激活Nrf2,而Nrf2抑制剂ML385逆转了4-OI对ROS生成和NLRP3炎症小体的抑制作用。3、4-OI治疗减轻了肥胖小鼠体重及血糖和血脂水平,改善了糖脂代谢紊乱。4-OI治疗降低了循环、肝脏和脂肪组织炎症因子水平,提高了肝脏和脂肪组织Nrf2蛋白表达及抑制NLRP3炎症小体激活。4-OI治疗抑制了肥胖小鼠BMDM在LPS诱导下炎症因子水平和NLRP3炎症小体激活。结论:1、与WT小鼠相比,衣康酸缺乏的IRG1-/-小鼠对饮食诱导的肥胖更加敏感,糖脂代谢紊乱更加严重,循环、肝脏、脂肪组织和BMDM炎症水平升高,NLRP3炎症小体激活增加。表明衣康酸缺乏会促进肥胖代谢性炎症的发生发展。2、衣康酸衍生物4-OI通过激活Nrf2,抑制ROS生成,进而阻断NLRP3炎症小体激活,减轻PA诱导的巨噬细胞炎症反应。3、4-OI治疗抑制了肥胖小鼠肝脏、脂肪组织和BMDM中NLRP3炎症小体激活,减轻了循环和组织炎症,改善了肥胖期间的糖脂代谢紊乱,有望成为干预肥胖代谢性炎症的新策略。更多还原

【Abstract】 Objective: Metaflammation plays a key role in the process of metabolic complications caused by obesity.Inflammatory activation of macrophages is a key link in metaflammation.Itaconate has recently been found to have a strong immunomodulatory effect on macrophages,showing good therapeutic potential in a variety of inflammatory diseases.The aim of this work was to investigate the function of itaconate in metaflammation.Methods: 1.Wild type(WT)and IRG1-/-mice were fed high fat diet to induce obesity model,to study the effects of itaconate deficiency on metaflammation of obesity.The experimental groups were: WT+normal diet group,IRG1-/-+normal diet group,WT+high fat diet group,IRG1-/-+high fat diet group.Detecting the glucose and lipid metabolism,and the levels of circulating,adipose tissue,liver and bone marrow-derived macrophage(BMDM)inflammation.2.Palmitic acid(PA)was used to induce macrophage inflammatory response,and the molecular mechanism of itaconate derivative 4-OI regulating macrophage inflammation was explored in vitro.3.To explore the feasibility of 4-OI therapy to improve metaflammation in obesity by exogenous supplement of itaconate derivative 4-OI.The experimental groups were:normal diet group,high fat diet group,and high fat diet+4-OI treatment group.Detecting the glucose and lipid metabolism,and the levels of circulating,liver,adipose tissue and BMDM inflammation.Results: 1.IRG1-/-mice were more sensitive to high fat diet induced obesity,with significantly increased body weight,liver weight and adipose tissue content.IRG1-/-mice had more serious glucose and lipid metabolism disorder during obesity.The levels of inflammatory cytokines IL-1β,IL-18 in circulation,liver and adipose tissue of IRG1-/-mice were significantly increased.In IRG1-/-mice liver and adipose tissue,there was a considerably higher level of NLRP3 inflammasome activation.IRG1-/-BMDM showed a stronger inflammatory response under LPS induction in vitro.2.In RAW 264.7 macrophages,itaconate derivative 4-OI inhibited PA-induced levels of IL-1β,IL-18 and NLRP3 inflammasome.4-OI inhibited PA-induced macrophage ROS production.Meanwhile,ROS inhibitor NAC could also significantly inhibit ROS production in macrophages,showing a similar inhibitory effect on NLRP3 inflammasome as 4-OI.4-OI could activate Nrf2,and Nrf2 inhibitor ML385 reversed the inhibitory effect of 4-OI on ROS production and NLRP3 inflammasome.3.4-OI treatment resulted in weight loss and improved the impaired glucose and lipid metabolism in obese mice.4-OI treatment decreased the levels of circulating,liver and adipose tissue inflammatory cytokines.In liver and adipose tissue,4-OI treatment increased Nrf2 protein and inhibited the NLRP3 inflammasome.4-OI treatment inhibited LPS-induced BMDM inflammatory response in obese mice.Conclusions: 1.In the high fat diet induced obesity model,compared with WT mice,IRG1-/-mice gained more weight,had more severe disorders of glucose and lipid metabolism,increased levels of circulatory,adipose tissue,liver and BMDM inflammation,and increased activation of NLRP3 inflammasome.These results suggest that itaconate deficiency may promote the development of metaflammation in obesity.2.Itaconate derivative 4-OI inhibited ROS production by activating Nrf2,and then blocked the activation of NLRP3 inflammasome,thus alleviating PA-induced macrophage inflammatory response.3.In obese mice,4-OI treatment inhibited NLRP3 inflammasome activation in liver,adipose tissue and BMDM,reduced the inflammation induced by obesity,and improved the disorder of glucose and lipid metabolism,which is expected to become a new strategy to intervene in metaflammation.更多还原