Department of Cardiology, The First Hospital of China Medical University, 155 Nanjing North Street, Heping District, Shenyang, 110001, Liaoning Province, People's Republic of China.
Center of Reproductive Medicine, Shengjing Hospital of China Medical University, Shenyang, 110004, China.
Cardiovasc Diabetol. 2023 May 6;22(1):107. doi: 10.1186/s12933-023-01818-3.
Endothelial injury caused by Type 2 diabetes mellitus (T2DM) is considered as a mainstay in the pathophysiology of diabetic vascular complications (DVCs). However, the molecular mechanism of T2DM-induced endothelial injury remains largely unknown. Here, we found that endothelial WW domain-containing E3 ubiquitin protein ligase 2 (WWP2) act as a novel regulator for T2DM-induced vascular endothelial injury through modulating ubiquitination and degradation of DEAD-box helicase 3 X-linked (DDX3X).
Single-cell transcriptome analysis was used to evaluate WWP2 expression in vascular endothelial cells of T2DM patients and healthy controls. Endothelial-specific Wwp2 knockout mice were used to investigate the effect of WWP2 on T2DM-induced vascular endothelial injury. In vitro loss- and gain-of-function studies were performed to assess the function of WWP2 on cell proliferation and apoptosis of human umbilical vein endothelial cells. The substrate protein of WWP2 was verified using mass spectrometry, coimmunoprecipitation assays and immunofluorescence assays. The mechanism of WWP2 regulation on substrate protein was investigated by pulse-chase assay and ubiquitination assay.
The expression of WWP2 was significantly down-regulated in vascular endothelial cells during T2DM. Endothelial-specific Wwp2 knockout in mice significantly aggravated T2DM-induced vascular endothelial injury and vascular remodeling after endothelial injury. Our in vitro experiments showed that WWP2 protected against endothelial injury by promoting cell proliferation and inhibiting apoptosis in ECs. Mechanically, we found that WWP2 is down-regulated in high glucose and palmitic acid (HG/PA)-induced ECs due to c-Jun N-terminal kinase (JNK) activation, and uncovered that WWP2 suppresses HG/PA-induced endothelial injury by catalyzing K63-linked polyubiquitination of DDX3X and targeting it for proteasomal degradation.
Our studies revealed the key role of endothelial WWP2 and the fundamental importance of the JNK-WWP2-DDX3X regulatory axis in T2DM-induced vascular endothelial injury, suggesting that WWP2 may serve as a new therapeutic target for DVCs.
2 型糖尿病（T2DM）引起的内皮损伤被认为是糖尿病血管并发症（DVCs）发病机制的主要因素。然而，T2DM 诱导的内皮损伤的分子机制在很大程度上仍然未知。在这里，我们发现内皮 WW 结构域包含 E3 泛素蛋白连接酶 2（WWP2）通过调节 DEAD 框解旋酶 3X 连锁（DDX3X）的泛素化和降解，作为 T2DM 诱导的血管内皮损伤的新型调节剂。
使用单细胞转录组分析评估 T2DM 患者和健康对照者血管内皮细胞中 WWP2 的表达。使用内皮特异性 Wwp2 敲除小鼠研究 WWP2 对 T2DM 诱导的血管内皮损伤的影响。体外进行缺失和功能获得研究，以评估 WWP2 对人脐静脉内皮细胞增殖和凋亡的作用。使用质谱、免疫共沉淀和免疫荧光检测鉴定 WWP2 的底物蛋白。通过脉冲追踪实验和泛素化实验研究 WWP2 对底物蛋白的调节机制。
T2DM 时血管内皮细胞中 WWP2 的表达显著下调。在小鼠中内皮特异性敲除 Wwp2 可显著加重内皮损伤后 T2DM 诱导的血管内皮损伤和血管重塑。我们的体外实验表明，WWP2 通过促进 ECs 增殖和抑制凋亡来保护内皮免受损伤。在机制上，我们发现由于 c-Jun N 末端激酶（JNK）的激活，WWP2 在高葡萄糖和棕榈酸（HG/PA）诱导的 ECs 中下调，并且发现 WWP2 通过催化 DDX3X 的 K63 连接多泛素化并将其靶向蛋白酶体降解来抑制 HG/PA 诱导的内皮损伤。
我们的研究揭示了内皮 WWP2 在 T2DM 诱导的血管内皮损伤中的关键作用，以及 JNK-WWP2-DDX3X 调节轴在其中的基本重要性，表明 WWP2 可能成为 DVCs 的新治疗靶点。
