Vascular endothelial cell senescence is a leading cause of age-associated and vascular diseases. Mammalian target of rapamycin complex 2 (mTORC2) is a conserved serine/threonine (Ser/Thr) protein kinase that plays an important regulatory role in various cellular processes. However, its impact on endothelial senescence remains controversial. In this study we investigated the role and molecular mechanisms of mTORC2 in endothelial senescence. A replicative senescence model and H₂O₂-induced premature senescence model were established in primary cultured human umbilical vein endothelial cells (HUVECs). In these senescence models, the formation and activation of mTORC2 were significantly increased, evidenced by the increases in binding of Rictor (the essential component of mTORC2) to mTOR, phosphorylation of mTOR at Ser2481 and phosphorylation of Akt (the effector of mTORC2) at Ser473. Knockdown of Rictor or treatment with the Akt inhibitor MK-2206 attenuated senescence-associated β-galactosidase (β-gal) staining and expression of p53 and p21 proteins in the senescent endothelial cells, suggesting that mTORC2/Akt facilitates endothelial senescence. The effect of mTORC2/Akt on endothelial senescence was due to suppression of nuclear factor erythroid 2-related factor 2 (Nrf2) at the transcriptional level, since knockdown of Rictor reversed the reduction of Nrf2 mRNA expression in endothelial senescence. Furthermore, mTORC2 suppressed the expression of Nrf2 via the Akt/GSK-3β/C/EBPα signaling pathway. These results suggest that the mTORC2/Akt/GSK-3β/C/EBPα/Nrf2 signaling pathway is involved in both replicative and inducible endothelial senescence. The deleterious role of mTORC2 in endothelial cell senescence suggests therapeutic strategies (targeting mTORC2) for aging-associated diseases and vascular diseases.

中文翻译：

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mTORC2通过经由Akt /GSK-3β/ C /EBPα信号通路抑制Nrf2表达，促进内皮细胞衰老。

血管内皮细胞衰老是与年龄有关的血管疾病的主要原因。雷帕霉素复合物2（mTORC2）的哺乳动物靶标是一种保守的丝氨酸/苏氨酸（Ser / Thr）蛋白激酶，在各种细胞过程中起着重要的调节作用。然而，其对内皮细胞衰老的影响仍存在争议。在这项研究中，我们研究了mTORC2在内皮细胞衰老中的作用和分子机制。复制衰老模型和H ₂ O ₂在原代培养的人脐静脉内皮细胞（HUVECs）中建立了人诱导的早衰模型。在这些衰老模型中，mTORC2的形成和激活显着增加，这由Rictor（mTORC2的基本组成部分）与mTOR的结合增加，在Ser2481处的mTOR磷酸化和在Ser473处的Akt的磷酸化（mTORC2的效应物）证明。 。敲除Rictor或使用Akt抑制剂MK-2206进行治疗可减弱衰老相关的衰老相关的β-半乳糖苷酶（β-gal）染色以及衰老内皮细胞中p53和p21蛋白的表达，这表明mTORC2 / Akt促进了内皮衰老。mTORC2 / Akt对内皮细胞衰老的影响是由于在转录水平上抑制了核因子红系2相关因子2（Nrf2），因为敲除Rictor可以逆转内皮细胞衰老过程中Nrf2 mRNA表达的降低。此外，mTORC2通过Akt /GSK-3β/ C /EBPα信号通路抑制Nrf2的表达。这些结果表明，mTORC2 / Akt /GSK-3β/ C /EBPα/ Nrf2信号通路参与复制性和诱导性内皮衰老。mTORC2在内皮细胞衰老中的有害作用提示了针对衰老相关疾病和血管疾病的治疗策略（靶向mTORC2）。