衣糖酸由免疫反应基因1(IRG1)编码的酶产生,并发挥抗菌作用,抗炎,和抗氧化作用通过多种机制。然而,IRG1/衣康酸在伴刀豆球蛋白A(ConA)引起的肝损伤中的作用尚不完全清楚。在这项研究中,我们探索了IRG1/四辛酯衣康酸(4-OI)的治疗效果,一种衣康酸酯的衍生物,关于ConA引起的肝损伤及其可能的潜在机制。体内实验,我们发现ConA促进肝脏组织中IRG1的表达。小鼠IRG1的缺失加重了ConA诱导的肝损伤。与野生型(WT)小鼠相比,炎症反应,肝细胞凋亡,血清细胞因子水平显著升高,而IRG1-/-小鼠的抗氧化能力显著减弱。此外,我们发现ConA促进核苷酸结合寡聚化结构域样受体家族pyrin结构域包含3个炎症小体,caspase-1和gasderminD激活,IRG1-/-小鼠的焦亡更为明显,而4-OI抑制焦亡。体内实验表明,ConA通过促进活性氧(ROS)表达促进肝细胞凋亡,和4-OI减少了ROS介导的NCTC1469细胞凋亡。在RAW264.7细胞中,我们证明4-OI通过促进核因子红系2[NF-E2]相关因子2(Nrf2)/血红素加氧酶-1(HO-1)通路和抑制核因子-κB(NF-κB)/丝裂原活化蛋白激酶信号通路来抑制炎症反应。为了进一步确认Nrf2是衣康酸的靶标,我们用Nrf2抑制剂ML385预处理WT小鼠,发现ML385对ConA诱导的小鼠肝损伤模型中4-OI的保护作用减弱。此外,当我们敲除NCTC1469和RAW264.7细胞中的Nrf2基因时,4-OI抑制炎症和细胞凋亡的作用也降低。总之,我们的研究表明IRG1在炎症和氧化应激中的重要性,提示其在ConA诱导的肝损伤中起着重要的保护作用。这些发现表明IRG1/衣康酸是一种潜在的治疗策略免疫性肝损伤,这需要进一步的临床探索。
Itaconate is produced by an enzyme encoded by the immune-responsive gene 1 (IRG1) and exerts antibacterial, anti-inflammatory, and antioxidant effects via multiple mechanisms. However, the role of IRG1/itaconate in liver injury caused by Concanavalin A (Con A) is not fully understood. In this study, we explored the therapeutic effect of IRG1/four-octyl itaconate (4-OI), a derivative of itaconate, on liver injury caused by Con A and its possible underlying mechanisms. In vivo experiments, we found that Con A promoted IRG1 expression in the liver tissue. Deletion of IRG1 in mice aggravated Con A-induced liver injury. Compared to wild-type (WT) mice, the inflammatory response, hepatocyte apoptosis, and serum cytokine levels were significantly increased, while the antioxidant capacity was significantly attenuated in IRG1-/- mice. In addition, we found that Con A promoted the nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 inflammasome, caspase-1, and gasdermin D activation, and pyroptosis was more obvious in IRG1-/- mice, while 4-OI inhibited pyroptosis. In vivo experiments showed that Con A promoted hepatocyte apoptosis by promoting reactive oxygen species (ROS) expression, and 4-OI reduced ROS-mediate apoptosis in NCTC 1469 cells. In RAW264.7 cells, we demonstrated that 4-OI inhibited the inflammatory response by promoting the nuclear factor erythroid 2 [NF-E2]-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) pathway and inhibiting the nuclear factor-kappa B (NF-κB)/mitogen-activated protein kinases signaling pathway. To further confirm that Nrf2 is the target of itaconate, we pretreated WT mice with ML385, an Nrf2 inhibitor, and found that ML385 could weaken the protection of 4-OI in Con A-induced liver injury mouse model. Furthermore, when we knocked down the Nrf2 gene in NCTC 1469 and RAW264.7 cells, the effect of 4-OI in inhibiting inflammation and apoptosis also decreased. In conclusion, our study shows the importance of IRG1 in inflammation and oxidative stress, and suggests that it plays a vital protective role in Con A-induced liver injury. These findings indicate IRG1/itaconate is a potential therapeutic strategy for immune liver injury, which requires further clinical exploration.