Chen Keke, Chen Chengjie, Chen Sihu, Zheng Xiang, Pan Guoquan, Liang Yafeng
Department of Pediatric Emergency, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, 325000, Zhejiang Province, PR China.
Department of Pediatric Intensive Care Unit, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, 325000, Zhejiang Province, PR China.
Eur J Pharmacol. 2025 Sep 5;1002:177818. doi: 10.1016/j.ejphar.2025.177818. Epub 2025 Jun 7.
Sepsis-induced acute lung injury (ALI) is a critical condition with a limited number of treatment options. The regulatory role of long noncoding RNA cancer susceptibility candidate 9 (lncRNA CASC9) in ferroptosis, a specific type of cell death, has been linked to this condition.
In this study, HPAEpiCs were treated with lipopolysaccharide (LPS) to model sepsis-induced acute lung injury. Various assays were employed, including RNA immunoprecipitation (RIP) and RNA pull-down to investigate lncRNA CASC9 interactions with U2 small nuclear RNA auxiliary factor 2 (U2AF2) and Mucin 1 (MUC1), Cell Counting Kit-8 (CCK-8) for cell viability, ELISA for inflammatory cytokines, Calcein-AM/PI staining for live/dead cell visualization, Reagent kit detection of lipid reactive oxygen species (ROS) and Malondialdehyde (MDA) assays for oxidative stress markers, iron and Glutathione (GSH) assays for redox status, qPCR for gene expression, and Western blot for protein levels.
The expression of lncRNA CASC9 was significantly decreased in LPS-induced cell models. Overexpression of lncRNA CASC9 reduced ferroptosis, as indicated by improved cell viability, decreased inflammatory cytokines, and restored redox homeostasis (reduced MDA and ROS, and iron levels, and increased GSH level). The lncRNA CASC9 interacts with U2AF2 to stabilize MUC1 mRNA, enhance MUC1 expression and reduce ferroptosis. Knockdown of U2AF2 reversed these effects, highlighting lncRNA CASC9's regulatory role in ferroptosis via MUC1 stabilization. MUC1 overexpression similarly reduced LPS-induced ferroptosis, supporting the protective role of the lncRNA CASC9/U2AF2/MUC1 pathway.
This study demonstrated that lncRNA CASC9 regulates sepsis-induced ALI by stabilizing MUC1 mRNA through U2AF2 interaction, thereby inhibiting ferroptosis.
脓毒症诱导的急性肺损伤（ALI）是一种危急病症，治疗选择有限。长链非编码RNA癌症易感性候选基因9（lncRNA CASC9）在铁死亡（一种特定类型的细胞死亡）中的调节作用与这种病症有关。
在本研究中，用脂多糖（LPS）处理人肺上皮细胞（HPAEpiCs）以模拟脓毒症诱导的急性肺损伤。采用了各种检测方法，包括RNA免疫沉淀（RIP）和RNA下拉实验，以研究lncRNA CASC9与U2小核RNA辅助因子2（U2AF2）和粘蛋白1（MUC1）的相互作用；使用细胞计数试剂盒-8（CCK-8）检测细胞活力，酶联免疫吸附测定（ELISA）检测炎性细胞因子，钙黄绿素-AM/碘化丙啶（Calcein-AM/PI）染色观察活/死细胞，试剂盒检测脂质活性氧（ROS），丙二醛（MDA）测定检测氧化应激标志物，铁和谷胱甘肽（GSH）测定检测氧化还原状态，实时定量聚合酶链反应（qPCR）检测基因表达，蛋白质印迹法检测蛋白质水平。
在LPS诱导的细胞模型中，lncRNA CASC9的表达显著降低。lncRNA CASC9的过表达减少了铁死亡，表现为细胞活力提高、炎性细胞因子减少以及氧化还原稳态恢复（MDA、ROS和铁水平降低，GSH水平升高）。lncRNA CASC9与U2AF2相互作用以稳定MUC1 mRNA，增强MUC1表达并减少铁死亡。敲低U2AF2可逆转这些作用，突出了lncRNA CASC9通过稳定MUC1在铁死亡中的调节作用。MUC1过表达同样减少了LPS诱导的铁死亡，支持lncRNA CASC9/U2AF2/MUC1途径的保护作用。
本研究表明，lncRNA CASC9通过与U2AF2相互作用稳定MUC1 mRNA，从而抑制铁死亡，进而调节脓毒症诱导的ALI。
