Institute of Biochemistry I, Faculty of Medicine, Goethe-University Frankfurt, Germany.
Functional Proteomics, SFB 815 Core Unit, Goethe-University Frankfurt, Germany.
Redox Biol. 2019 Jan;20:204-216. doi: 10.1016/j.redox.2018.10.007. Epub 2018 Oct 19.
Mitochondrial derived reactive oxygen species (mtROS) are known for their signaling qualities in both physiology and pathology. To elucidate mitochondrial complex I-dependent ROS-signaling after lipopolysaccharide (LPS)-stimulation THP-1 macrophages with a knockdown of the transmembrane protein TMEM126B were generated. TMEM knockdown cells (sh126B) showed a reduced assembly of complex I and attenuated mtROS production. In these cells we identified protein oxidization by mtROS upon LPS-treatment using the BIAM switch assay coupled to liquid chromatography and mass spectrometry. One of the identified targets of mtROS was succinate dehydrogenase (SDH) flavoprotein subunit A (SDHA). Oxidation of SDHA decreased its enzymatic activity and pharmacological inhibition of SDH in turn stabilized hypoxia inducible factor (HIF)-1α and caused the subsequent, sustained expression of interleukin-1β (IL-1β). Oxidation of SDHA in sh126B cells was attenuated, while pharmacological inhibition of SDH by atpenin A5 restored IL-1β expression in sh126B cells upon LPS-treatment. Conclusively, oxidation of SDH by mtROS links an altered metabolism, i.e. succinate accumulation to HIF-1-driven, inflammatory changes in macrophages.
线粒体来源的活性氧（mtROS）因其在生理和病理中的信号特性而闻名。为了阐明脂多糖（LPS）刺激后依赖于线粒体复合物 I 的 ROS 信号转导，生成了跨膜蛋白 TMEM126B 敲低的 THP-1 巨噬细胞。TMEM 敲低细胞（sh126B）显示复合物 I 的组装减少，mtROS 产生减弱。在这些细胞中，我们使用 BIAM 开关测定法结合液相色谱和质谱法，鉴定了 LPS 处理后 mtROS 引起的蛋白质氧化。鉴定出的 mtROS 靶标之一是琥珀酸脱氢酶（SDH）黄素蛋白亚基 A（SDHA）。SDHA 的氧化降低了其酶活性，而 SDH 的药理学抑制又稳定了缺氧诱导因子（HIF）-1α，导致随后持续表达白细胞介素-1β（IL-1β）。sh126B 细胞中 SDHA 的氧化减弱，而 LPS 处理时，atpenin A5 对 SDH 的药理学抑制恢复了 sh126B 细胞中 IL-1β 的表达。总之，mtROS 对 SDH 的氧化将改变的代谢，即琥珀酸积累与巨噬细胞中 HIF-1 驱动的炎症变化联系起来。
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