Wang Wenhao, Feng Nana, Shi Qi, Yang Jichun, Tan Yulong, Zhou Wenyong, Shi Meng
Department of Thoracic and Cardiovascular Surgery, Huashan Hospital, Affiliated With Fudan University, Shanghai, China.
Department of Respiratory and Critical Medicine, Shanghai Eighth People's Hospital, Shanghai, China.
J Cell Mol Med. 2025 Jun;29(11):e70645. doi: 10.1111/jcmm.70645.
During ischemia, succinate accumulates and leads to significant damage to the tissues. The specific role of succinate in lung ischemia-reperfusion injury (LIRI) remains unresolved. Differential metabolites in LIRI were identified through untargeted metabolomics using gas chromatography-mass spectrometry (GC-MS). Type II alveolar epithelial cells (AECs) were cultured and subjected to hypoxia/reoxygenation (H/R) in vitro, while an in vivo LIRI model was developed using C57BL/6 mice. Cytokine levels, lung oedema, histopathological alterations and lung functionality were evaluated. Protein levels were analysed through Western blotting. The mitochondrial membrane potential (Δψm) was measured using the JC-1 fluorescent dye, and mitochondrial morphology in Type II AECs following H/R damage was observed with a transmission electron microscope (TEM). Oxidative stress and apoptosis markers were detected in lung tissues and Type II AECs. Succinate was increased in the peripheral serum of LIRI patients and the C57BL/6 mices model. Succinate pre-treatment promotes Type II AEC cell apoptosis and oxidative stress, inhibits mitochondrial membrane potential and damages the alveolar epithelial cells' mitochondrial activity after H/R. Meanwhile, succinate may considerably reduce the amounts of acyl-CoA oxidase 1 (ACOX1) and isocitrate dehydrogenase 2 (IDH2) protein expression. Importantly, N-acetyl-L-cysteine (NAC) was observed to dramatically retard succinate-induced cell apoptosis, mitochondrial dysfunction and ROS levels in alveolar epithelial cells following H/R in vivo, with succinate-neutralising antibodies protecting LIRI in vitro. In conclusion, during ischemia, the build-up of succinate contributes to the advancement of LIRI by enhancing mitochondrial oxidative stress and promoting cell apoptosis, and blocking succinate may be a potential target for LIRI treatment.
在缺血期间，琥珀酸会积累并导致组织严重损伤。琥珀酸在肺缺血再灌注损伤（LIRI）中的具体作用仍未明确。通过气相色谱 - 质谱联用（GC - MS）的非靶向代谢组学方法鉴定了LIRI中的差异代谢物。培养II型肺泡上皮细胞（AECs）并在体外进行缺氧/复氧（H/R）处理，同时使用C57BL/6小鼠建立体内LIRI模型。评估细胞因子水平、肺水肿、组织病理学改变和肺功能。通过蛋白质印迹分析蛋白质水平。使用JC - 1荧光染料测量线粒体膜电位（Δψm），并通过透射电子显微镜（TEM）观察H/R损伤后II型AECs中的线粒体形态。检测肺组织和II型AECs中的氧化应激和凋亡标志物。LIRI患者外周血清和C57BL/6小鼠模型中的琥珀酸水平升高。琥珀酸预处理促进II型AEC细胞凋亡和氧化应激，抑制线粒体膜电位，并在H/R后损害肺泡上皮细胞的线粒体活性。同时，琥珀酸可能显著降低酰基辅酶A氧化酶1（ACOX1）和异柠檬酸脱氢酶2（IDH₂）的蛋白质表达量。重要的是，观察到N - 乙酰 - L - 半胱氨酸（NAC）可显著延缓体内H/R后琥珀酸诱导的肺泡上皮细胞凋亡、线粒体功能障碍和ROS水平，琥珀酸中和抗体在体外可保护LIRI。总之，在缺血期间，琥珀酸的积累通过增强线粒体氧化应激和促进细胞凋亡促进LIRI的进展，阻断琥珀酸可能是LIRI治疗的潜在靶点。
