Department of Surgery, Morsani College of Medicine, University of South Florida, Tampa, FL, 33612, USA.
Proteomics Core, Morsani College of Medicine, University of South Florida, Tampa, FL, 33612, USA.
Redox Biol. 2021 Jan;38:101824. doi: 10.1016/j.redox.2020.101824. Epub 2020 Dec 1.
Sestrin2 (Sesn2) is a stress-inducible protein that declines with aging in the heart. We reported that rescue Sesn2 levels in aged mouse hearts through gene therapy improves the resistance of aged hearts to ischemia and reperfusion (I/R) insults. We hypothesize that Sesn2 as a scaffold protein maintains mitochondrial integrity to protect heart from ischemic injury during I/R. Young C57BL/6 J (3-6 months), aged C57BL/6 J (24-26 months), and young Sesn2 KO (3-6 months, C57BL/6 J background) mice were subjected to in vivo regional ischemia and reperfusion. The left ventricle was collected for transcriptomics, proteomics and metabolomics analysis. The results demonstrated that Sesn2 deficiency leads to aging-like cardiac diastolic dysfunction and intolerance to ischemia reperfusion stress. Seahorse analysis demonstrated that Sesn2 deficiency in aged and young Sesn2 KO versus young hearts lead to impaired mitochondrial respiration rate with defects in Complex I and Complex II activity. The Sesn2 targeted proteomics analysis revealed that Sesn2 plays a critical role in maintaining mitochondrial functional integrity through modulating mitochondria biosynthesis and assembling of oxidative phosphorylation (OXPHOS) complexes. The RNA-Seq data showed that alterations in the expression of mitochondrial compositional and functional genes and substrate metabolism related genes in young Sesn2 KO and aged versus young hearts. Further immunofluorescence and immunoprecipitation analysis demonstrated that Sesn2 is translocated into mitochondria and interacts with OXPHOS components to maintain mitochondrial integrity in response to I/R stress. Biochemical analysis revealed that Sesn2 is associated with citrate cycle components to modulate pyruvate dehydrogenase and isocitrate dehydrogenase activities during I/R stress. Thus, Sesn2 serves as a scaffold protein interacting with OXPHOS components to maintain mitochondrial integrity under I/R stress. Age-related downregulation of cardiac Sesn2 fragilizes mitochondrial functional integrity in response to ischemic stress.
Sesn2（Sesn2）是一种应激诱导蛋白，在心脏中随年龄增长而减少。我们曾报道，通过基因治疗挽救老年小鼠心脏中的 Sesn2 水平可提高老年心脏对缺血再灌注（I/R）损伤的抵抗力。我们假设 Sesn2 作为一种支架蛋白，可维持线粒体的完整性，以保护心脏在 I/R 期间免受缺血损伤。将年轻的 C57BL/6J（3-6 个月）、年老的 C57BL/6J（24-26 个月）和年轻的 Sesn2 KO（3-6 个月，C57BL/6J 背景）小鼠进行体内区域缺血和再灌注。收集左心室进行转录组学、蛋白质组学和代谢组学分析。结果表明，Sesn2 缺失导致类似衰老的心脏舒张功能障碍和不耐受缺血再灌注应激。 Seahorse 分析表明，与年轻心脏相比，年老和年轻 Sesn2 KO 的 Sesn2 缺失导致线粒体呼吸率受损，复合物 I 和复合物 II 活性缺陷。Sesn2 靶向蛋白质组学分析表明，Sesn2 通过调节线粒体生物合成和氧化磷酸化（OXPHOS）复合物的组装，在维持线粒体功能完整性方面发挥关键作用。RNA-Seq 数据显示，年轻 Sesn2 KO 和年老与年轻心脏中与线粒体组成和功能基因以及底物代谢相关基因的表达发生改变。进一步的免疫荧光和免疫沉淀分析表明，Sesn2 易位到线粒体中，并与 OXPHOS 成分相互作用，以维持线粒体完整性以应对 I/R 应激。生化分析表明，Sesn2 与柠檬酸循环成分相关联，以在 I/R 应激期间调节丙酮酸脱氢酶和异柠檬酸脱氢酶的活性。因此，Sesn2 作为一种支架蛋白与 OXPHOS 成分相互作用，以维持线粒体完整性在 I/R 应激下。与年龄相关的心脏 Sesn2 下调会使线粒体功能完整性在缺血应激下变得脆弱。
