Acetaminophen (APAP) overdose is the leading cause of drug-induced liver injury, and its prognosis depends on the balance between hepatocyte death and regeneration. Sirtuin 6 (SIRT6) has been reported to protect against oxidative stress-associated DNA damage. But whether SIRT6 regulates APAP-induced hepatotoxicity remains unclear. In this study, the protein expression of nuclear and total SIRT6 was up-regulated in mice liver at 6 and 48 h following APAP treatment, respectively. Sirt6 knockdown in AML12 cells aggravated APAP-induced hepatocyte death and oxidative stress, inhibited cell viability and proliferation, and downregulated CCNA1, CCND1 and CKD4 protein levels. Sirt6 knockdown significantly prevented APAP-induced NRF2 activation, reduced the transcriptional activities of GSTμ and NQO1 and the mRNA levels of Nrf2, Ho-1, Gstα and Gstμ. Furthermore, SIRT6 showed potential protein interaction with NRF2 as evidenced by co-immunoprecipitation (Co-IP) assay. Additionally, the protective effect of P53 against APAP-induced hepatocytes injury was Sirt6-dependent. The Sirt6 mRNA was significantly down-regulated in P53^−/− mice. P53 activated the transcriptional activity of SIRT6 and exerted interaction with SIRT6. Our results demonstrate that SIRT6 protects against APAP hepatotoxicity through alleviating oxidative stress and promoting hepatocyte proliferation, and provide new insights in the function of SIRT6 as a crucial docking molecule linking P53 and NRF2.

对乙酰氨基酚（APAP）过量是药物性肝损伤的主要原因，其预后取决于肝细胞死亡和再生之间的平衡。据报道，Sirtuin 6（SIRT6）可防止氧化应激相关的DNA损伤。但是，SIRT6是否调节APAP诱导的肝毒性仍不清楚。在这项研究中，分别在APAP处理后6和48小时，小鼠肝脏中核和总SIRT6的蛋白表达上调。AML12细胞中的Sirt6抑制加重了APAP诱导的肝细胞死亡和氧化应激，抑制了细胞活力和增殖，并下调了CCNA1，CCND1和CKD4蛋白水平。Sirt6基因敲低显着阻止了APAP诱导的NRF2激活，降低了SNP的转录活性GSTμ和NQO1以及Nrf2，Ho-1，Gstα和Gstμ的mRNA水平。此外，SIRT6显示出与NRF2潜在的蛋白质相互作用，这通过共免疫沉淀（Co-IP）分析得以证明。另外，P53对APAP诱导的肝细胞损伤的保护作用是Sirt6依赖性的。该SIRT6 mRNA表达显著的下调P53 ^{- / -}小鼠。P53激活SIRT6的转录活性与SIRT6进行互动。我们的结果表明，SIRT6通过减轻氧化应激和促进肝细胞增殖来防止APAP肝毒性，并为SIRT6作为连接P53和NRF2的关键对接分子的功能提供了新见解。