Department of Infectious Disease, Shanghai Ninth People's Hospital, Shanghai 200011, P.R. China.
Department of Infectious Disease, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, P.R. China.
Mol Med Rep. 2024 May;29(5). doi: 10.3892/mmr.2024.13205. Epub 2024 Mar 22.
Acute liver failure (ALF) is a complex syndrome characterized by overactivation of innate immunity, and the recruitment and differentiation of immune cells at inflammatory sites. The present study aimed to explore the role of microRNA (miRNA/miR)‑21 and its potential mechanisms underlying inflammatory responses in ALF. Baseline serum miR‑21 was analyzed in patients with ALF and healthy controls. In addition, miR‑21 antagomir was injected via the tail vein into C57BL/6 mice, and lipopolysaccharide/D‑galactosamine (LPS/GalN) was injected into mice after 48 h. The expression levels of miR‑21, Krüppel‑like‑factor‑6 (KLF6), autophagy‑related proteins and interleukin (IL)‑23, and hepatic pathology were then assessed in the liver tissue. Furthermore, THP‑1‑derived macrophages were transfected with a miRNA negative control, miR‑21 inhibitor, miR‑21 mimics or KLF6 overexpression plasmid, followed by treatment with or without rapamycin, and the expression levels of miR‑21, KLF6, autophagy‑related proteins and IL‑23 were evaluated. The results revealed that baseline serum miR‑21 levels were significantly upregulated in patients with ALF. In addition, LPS/GalN‑induced ALF was attenuated in the antagomir‑21 mouse group. KLF6 was identified as a target of miR‑21‑5p with one putative seed match site identified by TargetScan. A subsequent luciferase activity assay demonstrated a direct interaction between miR‑21‑5p and the 3'‑UTR of KLF6 mRNA. Further experiments suggested that miR‑21 promoted the expression of IL‑23 via inhibiting KLF6, which regulated autophagy. In conclusion, in the present study, baseline serum miR‑21 levels were highly upregulated in patients with ALF, antagomir‑21 attenuated LPS/GalN‑induced ALF in a mouse model, and miR‑21 could promote the expression of IL‑23 via inhibiting KLF6.
急性肝衰竭（ALF）是一种以固有免疫过度激活以及炎症部位免疫细胞募集和分化为特征的复杂综合征。本研究旨在探讨 microRNA（miRNA/miR）-21 的作用及其在 ALF 炎症反应中的潜在机制。分析了 ALF 患者和健康对照者的基线血清 miR-21 水平。此外，在 48 小时后，通过尾静脉向 C57BL/6 小鼠注射 miR-21 拮抗剂，并用脂多糖/半乳糖胺（LPS/GalN）注射小鼠。然后评估肝组织中 miR-21、Krüppel 样因子 6（KLF6）、自噬相关蛋白和白细胞介素（IL）-23 的表达水平以及肝病理。此外，用 miRNA 阴性对照物、miR-21 抑制剂、miR-21 模拟物或 KLF6 过表达质粒转染 THP-1 衍生的巨噬细胞，然后用或不用雷帕霉素处理，并评估 miR-21、KLF6、自噬相关蛋白和 IL-23 的表达水平。结果显示，ALF 患者的基线血清 miR-21 水平显著上调。此外，在 miR-21 拮抗剂小鼠组中，LPS/GalN 诱导的 ALF 减轻。KLF6 被鉴定为 miR-21-5p 的靶标，通过 TargetScan 鉴定出一个潜在的种子匹配位点。随后的荧光素酶活性测定表明 miR-21-5p 与 KLF6 mRNA 的 3'UTR 之间存在直接相互作用。进一步的实验表明，miR-21 通过抑制 KLF6 促进了 IL-23 的表达，从而调节了自噬。综上所述，在本研究中，ALF 患者的基线血清 miR-21 水平显著上调，antagomir-21 减轻了 LPS/GalN 诱导的小鼠 ALF，miR-21 可以通过抑制 KLF6 促进 IL-23 的表达。
