安徽医科大学Cheng Huang和Tao-tao Ma共同合作，近期取得重要工作进展。他们研究提出中性粒细胞胞外陷阱（NET）通过AIM2促进对乙酰氨基酚（APAP）诱导的小鼠急性肝损伤。相关研究成果2024年4月8日在线发表于《药理学报》杂志上。

据介绍，过量的对乙酰氨基酚（APAP）可诱导中性粒细胞活化和肝细胞死亡。随着肝细胞功能障碍和死亡，NETosis（一种中性粒细胞相关炎症）在APAP过量诱导的急性肝损伤（ALI）的进展中起着至关重要的作用。研究表明，活化的中性粒细胞倾向于向损伤部位迁移，并通过形成中性粒细胞外陷阱（NET）参与炎症过程。

研究人员探讨了NET是否参与肝细胞损伤并参与APAP诱导的ALI进展。通过注射过量（350 mg/kg）的APAP建立ALI小鼠模型，24小时之后采集血液和肝脏样本进行分析。研究人员发现，过量的APAP诱导肝细胞的多种程序性细胞死亡，包括焦亡、凋亡和坏死，并伴有肝组织和血清中NET标记物（MPO、citH3）的显著增加。连续两天预注射DNase1（10U，i.p.）可显著抑制NET的形成，减少PANoptosis（泛凋亡），从而减轻过量APAP诱导的ALI。

为了阐明肝细胞和中性粒细胞之间的通讯，研究人员在分离的中性粒细胞中诱导了NET的形成，并用NET处理HepaRG细胞。研究人员发现NET处理显著增加了GSDMD、caspase-3和MLKL的激活，而DNase1预处理则下调了这些蛋白质的表达。抑制AIM2（一种胞质固有免疫受体）消除了NET诱导的HepaRG细胞泛凋亡。

此外，过量APAP相关的ALI在AIM2KO小鼠中显著减弱，泛凋亡的发生频率较低。使用AAV9病毒在AIM2KO小鼠中恢复AIM2表达后，肝损伤和泛凋亡均加重。过量的APAP刺激mtROS的产生和线粒体DNA（mtDNA）的泄漏，并且mtDNA激活TLR9途径以促进NET的形成。

总之，这一研究结果揭示了APAP相关ALI中NET和泛凋亡的新机制，这可能是一个治疗靶点。

附：英文原文

Title: Neutrophil extracellular traps promote acetaminophen-induced acute liver injury in mice via AIM2

Author: Zeng, Fan-le, Zhang, Yuan, Wang, Zhong-hao, Zhang, Hui, Meng, Xue-teng, Wu, Yi-qin, Qian, Zhen-zhen, Ding, Yu-hao, Li, Jun, Ma, Tao-tao, Huang, Cheng

Issue&Volume: 2024-04-08

Abstract: Excessive acetaminophen (APAP) can induce neutrophil activation and hepatocyte death. Along with hepatocyte dysfunction and death, NETosis (a form of neutrophil-associated inflammation) plays a vital role in the progression of acute liver injury (ALI) induced by APAP overdose. It has been shown that activated neutrophils tend to migrate towards the site of injury and participate in inflammatory processes via formation of neutrophil extracellular traps (NETs). In this study we investigated whether NETs were involved in hepatocyte injury and contributed to APAP-induced ALI progression. ALI mouse model was established by injecting overdose (350mg/kg) of APAP. After 24h, blood and livers were harvested for analyses. We showed that excessive APAP induced multiple programmed cell deaths of hepatocytes including pyroptosis, apoptosis and necroptosis, accompanied by significantly increased NETs markers (MPO, citH3) in the liver tissue and serum. Preinjection of DNase1 (10 U, i.p.) for two consecutive days significantly inhibited NETs formation, reduced PANoptosis and consequently alleviated excessive APAP-induced ALI. In order to clarify the communication between hepatocytes and neutrophils, we induced NETs formation in isolated neutrophils, and treated HepaRG cells with NETs. We found that NETs treatment markedly increased the activation of GSDMD, caspase-3 and MLKL, while pre-treatment with DNase1 down-regulated the expression of these proteins. Knockdown of AIM2 (a cytosolic innate immune receptor) abolished NETs-induced PANoptosis in HepaRG cells. Furthermore, excessive APAP-associated ALI was significantly attenuated in AIM2KO mice, and PANoptosis occurred less frequently. Upon restoring AIM2 expression in AIM2KO mice using AAV9 virus, both hepatic injury and PANoptosis was aggravated. In addition, we demonstrated that excessive APAP stimulated mtROS production and mitochondrial DNA (mtDNA) leakage, and mtDNA activated the TLR9 pathway to promote NETs formation. Our results uncover a novel mechanism of NETs and PANoptosis in APAP-associated ALI, which might serve as a therapeutic target.

DOI: 10.1038/s41401-024-01239-2

Source: https://www.nature.com/articles/s41401-024-01239-2