BACKGROUND:S-Nitrosylation (SNO), a prototypic redox-based posttranslational modification, is involved in cardiovascular disease. Aortic aneurysm and dissection are high-risk cardiovascular diseases without an effective cure. The aim of this study was to determine the role of SNO of Septin2 in macrophages in aortic aneurysm and dissection.METHODS:Biotin-switch assay combined with liquid chromatography–tandem mass spectrometry was performed to identify the S-nitrosylated proteins in aortic tissue from both patients undergoing surgery for aortic dissection and Apoe^−/− mice infused with angiotensin II. Angiotensin II–induced aortic aneurysm model and β-aminopropionitrile–induced aortic aneurysm and dissection model were used to determine the role of SNO of Septin2 (SNO-Septin2) in aortic aneurysm and dissection development. RNA-sequencing analysis was performed to recapitulate possible changes in the transcriptome profile of SNO-Septin2 in macrophages in aortic aneurysm and dissection. Liquid chromatography–tandem mass spectrometry and coimmunoprecipitation were used to uncover the TIAM1-RAC1 (Ras-related C3 botulinum toxin substrate 1) axis as the downstream target of SNO-Septin2. Both R-Ketorolac and NSC23766 treatments were used to inhibit the TIAM1-RAC1 axis.RESULTS:Septin2 was identified S-nitrosylated at cysteine 111 (Cys111) in both aortic tissue from patients undergoing surgery for aortic dissection and Apoe^−/− mice infused with Angiotensin II. SNO-Septin2 was demonstrated driving the development of aortic aneurysm and dissection. By RNA-sequencing, SNO-Septin2 in macrophages was demonstrated to exacerbate vascular inflammation and extracellular matrix degradation in aortic aneurysm. Next, TIAM1 (T lymphoma invasion and metastasis-inducing protein 1) was identified as a SNO-Septin2 target protein. Mechanistically, compared with unmodified Septin2, SNO-Septin2 reduced its interaction with TIAM1 and activated the TIAM1-RAC1 axis and consequent nuclear factor-κB signaling pathway, resulting in stronger inflammation and extracellular matrix degradation mediated by macrophages. Consistently, both R-Ketorolac and NSC23766 treatments protected against aortic aneurysm and dissection by inhibiting the TIAM1-RAC1 axis.CONCLUSIONS:SNO-Septin2 drives aortic aneurysm and dissection through coupling the TIAM1-RAC1 axis in macrophages and activating the nuclear factor-κB signaling pathway–dependent inflammation and extracellular matrix degradation. Pharmacological blockade of RAC1 by R-Ketorolac or NSC23766 may therefore represent a potential treatment against aortic aneurysm and dissection.

中文翻译：

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Septin2 的 S-亚硝基化通过耦合巨噬细胞中的 TIAM1-RAC1 轴加剧主动脉瘤和夹层

背景：S-亚硝基化（SNO）是一种基于氧化还原的原型翻译后修饰，与心血管疾病有关。主动脉瘤和夹层是高危心血管疾病，目前尚无有效治疗方法。本研究的目的是确定Septin2的SNO在主动脉瘤和夹层巨噬细胞中的作用。方法：采用生物素开关法结合液相色谱-串联质谱法鉴定主动脉组织中的S-亚硝基化蛋白。接受主动脉夹层手术的患者和注射血管紧张素 II 的Apoe ^{−/−小鼠。}采用血管紧张素II诱导的主动脉瘤模型和β-氨基丙腈诱导的主动脉瘤和夹层模型来确定Septin2的SNO（SNO-Septin2）在主动脉瘤和夹层发展中的作用。进行 RNA 测序分析以概括主动脉瘤和夹层巨噬细胞中 SNO-Septin2 转录组谱可能发生的变化。使用液相色谱-串联质谱和免疫共沉淀揭示了 TIAM1-RAC1（Ras 相关 C3 肉毒杆菌毒素底物 1）轴作为 SNO-Septin2 的下游靶点。R-Ketorolac 和 NSC23766 治疗均用于抑制 TIAM1-RAC1 轴。 结果：在接受主动脉夹层手术的患者和输注了 Apoe −/−小鼠的主动脉^组织中，发现 Septin2 在半胱氨酸 111 (Cys111) 处 S-亚硝基化。血管紧张素II。SNO-Septin2 被证明可促进主动脉瘤和夹层的发展。通过RNA测序，巨噬细胞中的SNO-Septin2被证明会加剧主动脉瘤中的血管炎症和细胞外基质降解。接下来，TIAM1（T 淋巴瘤侵袭和转移诱导蛋白 1）被鉴定为 SNO-Septin2 靶蛋白。从机制上讲，与未修饰的 Septin2 相比，SNO-Septin2 减少了与 TIAM1 的相互作用，并激活了 TIAM1-RAC1 轴和随后的核因子-κB 信号通路，导致巨噬细胞介导的炎症和细胞外基质降解更强。一致的是，R-Ketorolac 和 NSC23766 治疗均通过抑制 TIAM1-RAC1 轴来预防主动脉瘤和夹层。结论：SNO-Septin2 通过耦合巨噬细胞中的 TIAM1-RAC1 轴并激活核因子-κB 信号来驱动主动脉瘤和夹层途径依赖性炎症和细胞外基质降解。因此，R-Ketorolac 或 NSC23766 对 RAC1 的药理学阻断可能代表一种针对主动脉瘤和夹层的潜在治疗方法。