Department of Pharmacology, Toxicology & Therapeutics, University of Kansas Medical Center, Kansas City, Kansas 66160, USA.
Toxicol Sci. 2021 Aug 3;182(2):327-345. doi: 10.1093/toxsci/kfab052.
An acetaminophen (APAP) overdose is the most common cause of acute liver failure in the United States. A hallmark characteristic of APAP hepatotoxicity is centrilobular necrosis. General, innate mechanisms such as lower amounts of GSH and higher cytochrome P450 2e1 expression in pericentral (PC) hepatocytes are known to contribute to the differences in susceptibility to cell injury between periportal (PP) hepatocytes and PC hepatocytes. Although a sequence of molecular events involving formation of the reactive metabolite N-acetyl-p-benzoquinone imine, GSH depletion, oxidative stress, and c-Jun N-terminal kinase activation define the early cell stress trajectory following APAP exposure, their activation in PC versus PP hepatocytes is not well characterized. By using single-cell RNA-sequencing, we provide the first reconstruction of the early transcriptomic APAP liver lobule after validation of our methodology using human liver single-cell RNA-sequencing data. Two hours after APAP treatment, we find that PP hepatocytes progress along the APAP stress axis to oxidative stress, before resolving injury due to innate and adaptive mechanisms. However, PC hepatocytes continue along this stress axis as indicated by activation of mitogen-activated protein kinase genes, which is absent in PP hepatocytes. We also identify a population of glutamine synthetase enriched PC hepatocytes in close proximity to the central vein, where a stepwise induction of a stress program culminated in cell death. Collectively, these findings elucidate a molecular sequence of events distinguishing the differential response to APAP exposure between PP and PC hepatocytes and identify a subset of uniquely susceptible PC hepatocytes.
对乙酰氨基酚（APAP）过量是美国急性肝衰竭的最常见原因。APAP 肝毒性的一个显著特征是中央小叶坏死。众所周知，一般的先天机制，如中心（PC）肝细胞中较低的 GSH 含量和较高的细胞色素 P450 2e1 表达，导致门脉周围（PP）肝细胞和 PC 肝细胞对细胞损伤的敏感性存在差异。尽管涉及形成反应性代谢物 N-乙酰-p-苯醌亚胺、GSH 耗竭、氧化应激和 c-Jun N 末端激酶激活的一系列分子事件定义了 APAP 暴露后早期细胞应激轨迹，但它们在 PC 与 PP 肝细胞中的激活情况尚未得到很好的描述。通过使用单细胞 RNA 测序，我们在使用人类肝脏单细胞 RNA 测序数据验证我们的方法学之后，首次重建了 APAP 肝小叶的早期转录组。APAP 处理 2 小时后，我们发现 PP 肝细胞沿着 APAP 应激轴进展到氧化应激，然后通过先天和适应性机制解决损伤。然而，PC 肝细胞继续沿着这条应激轴，这表明丝裂原活化蛋白激酶基因被激活，而 PP 肝细胞则没有。我们还在靠近中央静脉的 PC 肝细胞中鉴定出一组富含谷氨酰胺合成酶的细胞，其中一个应激程序的逐步诱导导致细胞死亡。总的来说，这些发现阐明了区分 PP 和 PC 肝细胞对 APAP 暴露的不同反应的分子事件序列，并确定了一组独特易感的 PC 肝细胞。
