National Local Joint Engineering Research Center for Precision Surgery & Regenerative Medicine, Shaanxi Provincial Center for Regenerative Medicine and Surgical Engineering, The First Affiliated Hospital of Xi'an Jiaotong University, 277 West Yanta Road, Xi'an 710061, Shaanxi Province, China.
Institute of Advanced Surgical Technology and Engineering, The First Affiliated Hospital of Xi'an Jiaotong University, 277 West Yanta Road, Xi'an 710061, Shaanxi Province, China.
Int J Biol Sci. 2023 Jul 31;19(12):3987-4003. doi: 10.7150/ijbs.84768. eCollection 2023.
N6-methyladenosine (mA) is the most common post-transcriptional modification of RNA in eukaryotes, which has been demonstrated to play important roles in various biological processes. However, its roles in fulminant hepatitis remain largely unknown. In the current study, YTHDF1 expression was found to be significantly downregulated in the livers among patients, as well as murine models with fulminant hepatitis versus normal controls. Thus, we hypothesized that YTHDF1 protects against fulminant hepatitis and investigated the underlying molecular mechanisms. Fulminant hepatitis was induced by D-GalN/LPS in conventional YTHDF1 knockout (YTHDF1) mice, hepatocyte-specific YTHDF1 overexpression (AAV8- YTHDF1) mice, and corresponding control mice. Primary hepatocytes were cultured and subjected to LPS insult . Hepatic histology, cell death, oxidative stress and mitochondrial function were examined to assess liver damage. The molecular mechanisms of YTHDF1 function were explored using multi-omics analysis. Ablation of YTHDF1 exacerbated hepatic apoptosis and reactive oxygen species (ROS) production and increased the number of aberrant mitochondria, while YTHDF1 overexpression resulted in the opposite effects. Multiomics analysis identified MFG-E8 as the direct target of YTHDF1. YTHDF1 augmented the translation of MFG-E8 in an mA-dependent manner without effect on its mRNA expression, thereby restoring mitochondrial function. Additionally, administration of MFG-E8 almost completely reversed the YTHDF1 deficiency-mediated exacerbation of liver injury. The current study suggested that the mA reader YTHDF1 alleviates cell death, enhances antioxidant capacity and restores mitochondrial function in fulminant hepatitis by promoting MFG-E8 protein translation in an mA-dependent manner.
N6-甲基腺苷（mA）是真核生物中 RNA 最普遍的转录后修饰，已被证明在各种生物过程中发挥重要作用。然而，其在暴发性肝炎中的作用仍知之甚少。在本研究中，与正常对照相比，患者和暴发性肝炎的小鼠模型肝脏中的 YTHDF1 表达明显下调。因此，我们假设 YTHDF1 可防止暴发性肝炎，并研究了其潜在的分子机制。在常规 YTHDF1 敲除（YTHDF1）小鼠、肝细胞特异性 YTHDF1 过表达（AAV8-YTHDF1）小鼠和相应的对照小鼠中，通过 D-GalN/LPS 诱导暴发性肝炎。培养原代肝细胞并进行 LPS 刺激。检查肝组织学、细胞死亡、氧化应激和线粒体功能，以评估肝损伤。使用多组学分析探讨 YTHDF1 功能的分子机制。YTHDF1 的缺失加剧了肝细胞凋亡和活性氧（ROS）的产生，并增加了异常线粒体的数量，而过表达 YTHDF1 则产生相反的效果。多组学分析确定 MFG-E8 是 YTHDF1 的直接靶标。YTHDF1 以 mA 依赖性方式增强 MFG-E8 的翻译，而不影响其 mRNA 表达，从而恢复线粒体功能。此外，MFG-E8 的给药几乎完全逆转了 YTHDF1 缺乏介导的肝损伤加重。本研究表明，mA 阅读器 YTHDF1 通过以 mA 依赖性方式促进 MFG-E8 蛋白翻译，减轻暴发性肝炎中的细胞死亡，增强抗氧化能力并恢复线粒体功能。
