Center for Cell Death, Injury & Regeneration, Medical University of South Carolina, Charleston, SC 29425, United States of America; Department of Drug Discovery & Biomedical Sciences, Medical University of South Carolina, Charleston, SC 29425, United States of America.
Center for Cell Death, Injury & Regeneration, Medical University of South Carolina, Charleston, SC 29425, United States of America; Department of Drug Discovery & Biomedical Sciences, Medical University of South Carolina, Charleston, SC 29425, United States of America; Department of Biochemistry & Molecular Biology, Medical University of South Carolina, Charleston, SC 29425, United States of America.
Toxicol Appl Pharmacol. 2020 Apr 1;392:114930. doi: 10.1016/j.taap.2020.114930. Epub 2020 Feb 25.
Acetaminophen (APAP) overdose causes hepatotoxicity involving mitochondrial dysfunction. Previous studies showed that translocation of Fe from lysosomes into mitochondria by the mitochondrial Ca uniporter (MCU) promotes the mitochondrial permeability transition (MPT) after APAP. Here, our Aim was to assess protection by iron chelation and MCU inhibition against APAP hepatotoxicity in mice. C57BL/6 mice and hepatocytes were administered toxic doses of APAP with and without starch-desferal (an iron chelator), minocycline (MCU inhibitor), or N-acetylcysteine (NAC). In mice, starch-desferal and minocycline pretreatment decreased ALT and liver necrosis after APAP by >60%. At 24 h after APAP, loss of fluorescence of mitochondrial rhodamine 123 occurred in pericentral hepatocytes often accompanied by propidium iodide labeling, indicating mitochondrial depolarization and cell death. Starch-desferal and minocycline pretreatment decreased mitochondrial depolarization and cell death by more than half. In cultured hepatocytes, cell killing at 10 h after APAP decreased from 83% to 49%, 35% and 27%, respectively, by 1 h posttreatment with minocycline, NAC, and minocycline plus NAC. With 4 h posttreatment in vivo, minocycline and minocycline plus NAC decreased ALT and necrosis by ~20% and ~50%, respectively, but NAC alone was not effective. In conclusion, minocycline and starch-desferal decrease mitochondrial dysfunction and severe liver injury after APAP overdose, suggesting that the MPT is likely triggered by iron uptake into mitochondria through MCU. In vivo, minocycline and minocycline plus NAC posttreatment after APAP protect at later time points than NAC alone, indicating that minocycline has a longer window of efficacy than NAC.
对乙酰氨基酚（APAP）过量会导致肝毒性，涉及线粒体功能障碍。先前的研究表明，线粒体钙单向转运体（MCU）将溶酶体中的铁转运到线粒体中，会促进 APAP 后线粒体通透性转换（MPT）。在此，我们的目的是评估铁螯合剂和 MCU 抑制剂对 APAP 肝毒性的保护作用。用有毒剂量的 APAP 处理 C57BL/6 小鼠和肝细胞，同时给予淀粉-去铁胺（一种铁螯合剂）、米诺环素（MCU 抑制剂）或 N-乙酰半胱氨酸（NAC）。在小鼠中，淀粉-去铁胺和米诺环素预处理可使 APAP 后 ALT 和肝坏死减少 60%以上。APAP 后 24 小时，中心周围肝细胞中线粒体罗丹明 123 的荧光丧失常伴有碘化丙啶标记，表明线粒体去极化和细胞死亡。淀粉-去铁胺和米诺环素预处理可使线粒体去极化和细胞死亡减少一半以上。在培养的肝细胞中，APAP 后 10 小时的细胞杀伤率分别降低了 83%、49%、35%和 27%，1 小时后用米诺环素、NAC 和米诺环素加 NAC 处理。体内处理 4 小时后，米诺环素和米诺环素加 NAC 分别使 ALT 和坏死减少约 20%和 50%，但 NAC 单独无效。结论：米诺环素和淀粉-去铁胺可减少 APAP 过量后线粒体功能障碍和严重肝损伤，表明 MPT 可能是通过 MCU 将铁摄取到线粒体中触发的。在体内，APAP 后用米诺环素和米诺环素加 NAC 处理比单独用 NAC 处理的时间晚，表明米诺环素的疗效比 NAC 长。
