背景:巨噬细胞是先天性免疫细胞,其吞噬功能对中风和腹膜炎的预后至关重要。顺式脱羧酶免疫应答基因1(Irg1)及其代谢产物衣康酸抑制细菌感染,细胞内病毒复制,和巨噬细胞的炎症。在这里,我们探讨衣康酸酯是否调节吞噬作用。
方法:通过延时录像研究巨噬细胞的吞噬作用,流式细胞术,和从小鼠组织分离的巨噬细胞/小胶质细胞培养物中的免疫荧光染色。使用无偏RNA测序和ChIP测序测定来探索潜在的机制。在转基因(Irg1flox/flox;Cx3cr1creERT/+,cKO)小鼠或体内对照小鼠。
结果:在ICH的小鼠模型中,巨噬细胞/小胶质细胞中Irg1的消耗降低了其对红细胞的吞噬作用,从而加剧结果(n=10只动物/组,p<0.05)。施用衣康酸钠/4-辛基衣康酸(4-OI)促进巨噬细胞吞噬(n=7只动物/组,p<0.05)。此外,在腹膜炎的小鼠模型中,巨噬细胞中的Irg1缺乏也抑制了金黄色葡萄球菌的吞噬作用(n=5只动物/组,p<0.05)和加重的结果(n=9只动物/组,p<0.05)。机械上,Kelch样ECH相关蛋白1(Keap1)上的4-OI烷基化半胱氨酸155,核因子红系2相关因子2(Nrf2)的核易位和Cd36基因的转录激活。阻断CD36的功能完全消除了体外和体内Irg1/衣康酸酯轴的吞噬作用。
结论:我们的发现为吞噬作用缺乏症提供了一个潜在的治疗靶点,支持进一步发展为中风和腹膜炎患者的临床应用。
背景:国家自然科学基金(32070735,82371321,82271240,杨飞)和北京市自然科学基金项目和北京市教委科学研究重点项目(KZ202010025033,李问)。
BACKGROUND: Macrophages are innate immune cells whose phagocytosis function is critical to the prognosis of stroke and peritonitis. cis-aconitic decarboxylase immune-responsive gene 1 (
Irg1) and its metabolic product itaconate inhibit bacterial infection, intracellular viral replication, and inflammation in macrophages. Here we explore whether itaconate regulates phagocytosis.
METHODS: Phagocytosis of macrophages was investigated by time-lapse video recording, flow cytometry, and immunofluorescence staining in macrophage/microglia cultures isolated from mouse tissue. Unbiased RNA-sequencing and ChIP-sequencing assays were used to explore the underlying mechanisms. The effects of
Irg1/itaconate axis on the prognosis of intracerebral hemorrhagic stroke (ICH) and peritonitis was observed in transgenic (Irg1flox/flox; Cx3cr1creERT/+, cKO) mice or control mice in vivo.
RESULTS: In a mouse model of ICH, depletion of
Irg1 in macrophage/microglia decreased its phagocytosis of erythrocytes, thereby exacerbating outcomes (n = 10 animals/group, p < 0.05). Administration of sodium itaconate/4-octyl itaconate (4-OI) promoted macrophage phagocytosis (n = 7 animals/group, p < 0.05). In addition, in a mouse model of peritonitis,
Irg1 deficiency in macrophages also inhibited phagocytosis of Staphylococcus aureus (n = 5 animals/group, p < 0.05) and aggravated outcomes (n = 9 animals/group, p < 0.05). Mechanistically, 4-OI alkylated cysteine 155 on the Kelch-like ECH-associated protein 1 (Keap1), consequent in nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) and transcriptional activation of Cd36 gene. Blocking the function of CD36 completely abolished the phagocytosis-promoting effects of
Irg1/itaconate axis in vitro and in vivo.
CONCLUSIONS: Our findings provide a potential therapeutic target for phagocytosis-deficiency disorders, supporting further development towards clinical application for the benefit of stroke and peritonitis patients.
BACKGROUND: The National Natural Science Foundation of China (32070735, 82371321 to Q. Li, 82271240 to F. Yang) and the Beijing Natural Science Foundation Program and Scientific Research Key Program of Beijing Municipal Commission of Education (KZ202010025033 to Q. Li).