Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
Department of Environmental and Occupational Health, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
J Clin Invest. 2022 Jan 4;132(1). doi: 10.1172/JCI151685.
Altered redox biology challenges all cells, with compensatory responses often determining a cell's fate. When 15 lipoxygenase 1 (15LO1), a lipid-peroxidizing enzyme abundant in asthmatic human airway epithelial cells (HAECs), binds phosphatidylethanolamine-binding protein 1 (PEBP1), hydroperoxy-phospholipids, which drive ferroptotic cell death, are generated. Peroxidases, including glutathione peroxidase 4 (GPX4), metabolize hydroperoxy-phospholipids to hydroxy derivatives to prevent ferroptotic death, but consume reduced glutathione (GSH). The cystine transporter SLC7A11 critically restores/maintains intracellular GSH. We hypothesized that high 15LO1, PEBP1, and GPX4 activity drives abnormal asthmatic redox biology, evidenced by lower bronchoalveolar lavage (BAL) fluid and intraepithelial cell GSH:oxidized GSH (GSSG) ratios, to enhance type 2 (T2) inflammatory responses. GSH, GSSG (enzymatic assays), 15LO1, GPX4, SLC7A11, and T2 biomarkers (Western blot and RNA-Seq) were measured in asthmatic and healthy control (HC) cells and fluids, with siRNA knockdown as appropriate. GSSG was higher and GSH:GSSG lower in asthmatic compared with HC BAL fluid, while intracellular GSH was lower in asthma. In vitro, a T2 cytokine (IL-13) induced 15LO1 generation of hydroperoxy-phospholipids, which lowered intracellular GSH and increased extracellular GSSG. Lowering GSH further by inhibiting SLC7A11 enhanced T2 inflammatory protein expression and ferroptosis. Ex vivo, redox imbalances corresponded to 15LO1 and SLC7A11 expression, T2 biomarkers, and worsened clinical outcomes. Thus, 15LO1 pathway-induced redox biology perturbations worsen T2 inflammation and asthma control, supporting 15LO1 as a therapeutic target.
氧化还原生物学改变了所有细胞，细胞的命运往往取决于补偿性反应。当 15 脂氧合酶 1（15LO1）——一种在哮喘患者气道上皮细胞（HAECs）中丰富的脂质过氧化物酶——与磷酯酰乙醇胺结合蛋白 1（PEBP1）结合时，会产生驱动铁死亡的过氧化物磷脂。过氧化物酶，包括谷胱甘肽过氧化物酶 4（GPX4），会将过氧化物磷脂代谢为羟基衍生物，以防止铁死亡，但会消耗还原型谷胱甘肽（GSH）。半胱氨酸转运蛋白 SLC7A11 对细胞内 GSH 的恢复/维持至关重要。我们假设高 15LO1、PEBP1 和 GPX4 活性会导致异常的哮喘氧化还原生物学，这表现在支气管肺泡灌洗液（BAL）和上皮细胞内 GSH：氧化 GSH（GSSG）比值降低，以增强 2 型（T2）炎症反应。在哮喘和健康对照（HC）细胞和液体中测量 GSH、GSSG（酶促测定）、15LO1、GPX4、SLC7A11 和 T2 生物标志物（Western blot 和 RNA-Seq），并进行适当的 siRNA 敲低。与 HC BAL 液相比，哮喘患者的 GSSG 更高，GSH：GSSG 更低，而细胞内 GSH 水平较低。在体外，T2 细胞因子（IL-13）诱导 15LO1 生成过氧化物磷脂，从而降低细胞内 GSH 并增加细胞外 GSSG。通过抑制 SLC7A11 进一步降低 GSH 会增强 T2 炎症蛋白表达和铁死亡。离体时，氧化还原失衡与 15LO1 和 SLC7A11 表达、T2 生物标志物和临床结果恶化相对应。因此，15LO1 通路诱导的氧化还原生物学改变会加重 T2 炎症和哮喘控制，支持将 15LO1 作为治疗靶点。
