Department of Hepatobiliary Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, China.
Key Laboratory of Coal Science and Technology of Ministry of Education, College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan 030000, China.
Sci Total Environ. 2023 Jun 20;878:163069. doi: 10.1016/j.scitotenv.2023.163069. Epub 2023 Mar 28.
The threat to public health posed by rapidly increasing levels of cadmium (Cd) in the environment is receiving worldwide attention. Although, Cd is known to be absorbed into the body and causes non-negligible damage to the liver, the detailed mechanisms underlying its hepatoxicity are incompletely understood. In the present study, investigated the effect of TNFAIP3 and α-ketoglutarate (AKG) on Cd-induced liver inflammation and hepatocyte death. Male C57BL/6 mice were exposed to cadmium chloride (1.0 mg/kg) while being fed a diet with 2 % AKG for two weeks. We found that Cd induced hepatocyte injury and inflammatory infiltration. In addition, TNFAIP3 expression was inhibited in the liver tissues and cells of CdCl-treated mice. Mouse hepatocyte-specific TNFAIP3 overexpression by tail vein injection of an adeno-associated virus (AAV) vector effectively alleviated Cd-induced hepatic necrosis and inflammation, which was mediated by the NF-κB signaling pathway. Notably, this inhibitory effect of TNFAIP3 on Cd-induced liver injury was dependent on AKG. Exogenous addition of AKG prevented Cd exposure-induced increases in serum ALT, AST and LDH levels, production of pro-inflammatory cytokines, activation of the NF-κB signaling pathway, and even significantly reduced Cd-induced oxidative stress and hepatocyte death. Mechanistically, AKG exerted its anti-inflammatory effect by promoting the hydroxylation and degradation of HIF1A to reduce its Cd-induced overexpression in vivo and in vitro, avoiding the inhibition of the TNFAIP3 promoter by HIF1A. Moreover, the protective effect of AKG was significantly weaker in Cd-treated primary hepatocytes transfected with HIF1A pcDNA. Overall, our results reveal a novel mechanism of Cd-induced hepatotoxicity.
环境中镉(Cd)水平的迅速增加对公共健康构成的威胁正引起全球关注。虽然已知 Cd 会被人体吸收,并对肝脏造成不可忽视的损害,但它的肝毒性的详细机制尚不完全清楚。在本研究中,我们研究了 TNFAIP3 和 α-酮戊二酸(AKG)对 Cd 诱导的肝炎症和肝细胞死亡的影响。雄性 C57BL/6 小鼠在摄入氯化镉(1.0mg/kg)的同时,以含有 2%AKG 的饮食喂养两周。我们发现 Cd 诱导了肝细胞损伤和炎症浸润。此外,CdCl 处理小鼠的肝组织和细胞中 TNFAIP3 的表达受到抑制。通过尾静脉注射腺相关病毒(AAV)载体实现的小鼠肝细胞特异性 TNFAIP3 过表达,有效地缓解了 Cd 诱导的肝坏死和炎症,这是通过 NF-κB 信号通路介导的。值得注意的是,TNFAIP3 对 Cd 诱导的肝损伤的抑制作用依赖于 AKG。外源性添加 AKG 可防止 Cd 暴露引起的血清 ALT、AST 和 LDH 水平升高、促炎细胞因子的产生、NF-κB 信号通路的激活,甚至显著降低 Cd 诱导的氧化应激和肝细胞死亡。从机制上讲,AKG 通过促进 HIF1A 的羟化和降解来发挥其抗炎作用,从而减少体内和体外 Cd 诱导的 HIF1A 过表达,避免 HIF1A 抑制 TNFAIP3 启动子。此外,在 Cd 处理的转染了 HIF1A pcDNA 的原代肝细胞中,AKG 的保护作用明显较弱。总的来说,我们的研究结果揭示了 Cd 诱导的肝毒性的一种新机制。