Department of Ophthalmology, Fudan Eye & ENT Hospital, Shanghai 200031, China.
Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai 200031, China.
J Clin Endocrinol Metab. 2022 Jun 16;107(7):1994-2003. doi: 10.1210/clinem/dgac163.
Oxidative stress plays an indispensable role in pathogenesis of Graves' orbitopathy (GO). Ferroptosis is a newly discovered form of cell death resulting from lipid peroxidation. Little is known about the role of ferroptosis in GO.
We aimed to identify the divergent role of ferroptosis in the GO and control orbital fibroblasts (OFs).
Orbital fat/connective tissues and serum immunoglobulins (Igs) were collected from GO and control subjects. Cell viability and lipid peroxidation were measured to evaluate ferroptosis sensitivity. Pyruvate dehydrogenase kinase 2 (PDK2) level and oxygen consumption rate were quantified to assess glycolysis status.
Primary OFs were cultured from orbital tissues. Ferroptosis was induced by cystine deprivation and/or erastin treatment. The GO OFs possessed stronger resistance to ferroptosis than the control OFs. Selenium, a potential ferroptosis inhibitor, protected the control OFs from ferroptosis. Both transcriptomic and proteomic analyses indicated glycolytic shift in the GO OFs. Metabolic profiling, PDK2 quantification, and oxygen consumption assay confirmed enhanced glycolysis in the GO OFs. Inhibition of glycolysis by PDK2 knockdown and dichloroacetic acid (DCA) promoted ferroptosis sensitivity in the GO OFs. The ferroptosis-sensitizing effects of DCA were also observed when the GO OFs were treated with GO-Igs. IGF1R overexpression in the GO OFs contributed to glycolysis shift. IGF1R inhibitory antibodies facilitated ferroptosis induction in the GO OFs, but the effects were less remarkable under GO-Igs treatment.
These study findings establish that glycolysis facilitates ferroptosis resistance in the GO OFs, providing insights into the therapeutic role of glycolysis for GO treatment.
氧化应激在格雷夫斯眼病（GO）的发病机制中起着不可或缺的作用。铁死亡是一种新发现的细胞死亡形式，由脂质过氧化引起。关于铁死亡在 GO 中的作用知之甚少。
我们旨在确定铁死亡在 GO 和对照眼眶成纤维细胞（OFs）中的不同作用。
从 GO 和对照受试者中收集眼眶脂肪/结缔组织和血清免疫球蛋白（Igs）。测量细胞活力和脂质过氧化来评估铁死亡敏感性。量化丙酮酸脱氢酶激酶 2（PDK2）水平和耗氧量来评估糖酵解状态。
从眼眶组织培养原代 OFs。用胱氨酸剥夺和/或 erastin 处理诱导铁死亡。GO OFs 对铁死亡的抵抗力强于对照 OFs。硒，一种潜在的铁死亡抑制剂，可保护对照 OFs 免受铁死亡。转录组和蛋白质组分析均表明 GO OFs 存在糖酵解转移。代谢谱分析、PDK2 定量和耗氧测定证实 GO OFs 中糖酵解增强。PDK2 敲低和二氯乙酸（DCA）抑制糖酵解促进 GO OFs 中铁死亡敏感性。当 GO OFs 用 GO-Igs 处理时，DCA 也观察到铁死亡致敏作用。GO OFs 中的 IGF1R 过表达导致糖酵解转移。IGF1R 抑制性抗体促进 GO OFs 中铁死亡诱导，但在 GO-Igs 治疗下效果不明显。
这些研究结果表明，糖酵解促进 GO OFs 中铁死亡抵抗，为 GO 治疗的糖酵解治疗作用提供了新的见解。
