Department of Pharmacology, Beijing Key Laboratory of Cardiovascular Diseases Related to Metabolic Disturbance, Capital Medical University, Beijing, 100069, China.
Beijing Friendship Hospital, The Affiliated Hospital of Capital Medical University, Beijing, 100065, China.
Acta Pharmacol Sin. 2023 Dec;44(12):2492-2503. doi: 10.1038/s41401-023-01127-1. Epub 2023 Jul 19.
Endothelial dysfunction, a central hallmark of cardiovascular pathogenesis in diabetes mellitus, is characterized by impaired endothelial nitric oxide synthase (eNOS) and NO bioavailability. However, the underlying mechanisms remain unclear. Here in this study, we aimed to identify the role of calmodulin (CaM) in diabetic eNOS dysfunction. Human umbilical vein endothelial cells and murine endothelial progenitor cells (EPCs) treated with high glucose (HG) exhibited downregulated CaM mRNA/protein and vascular endothelial growth factor (VEGF) expression with impeded eNOS phosphorylation and cell migration/tube formation. These perturbations were reduplicated in CALM1-knockdown cells but prevented in CALM1-overexpressing cells. EPCs from type 2 diabetes animals behaved similarly to HG-treated normal EPCs, which could be rescued by CALM1-gene transduction. Consistently, diabetic animals displayed impaired eNOS phosphorylation, endothelium-dependent dilation, and CaM expression in the aorta, as well as deficient physical interaction of CaM and eNOS in the gastrocnemius. Local CALM1 gene delivery into a diabetic mouse ischemic hindlimb improved the blunted limb blood perfusion and gastrocnemius angiogenesis, and foot injuries. Diabetic patients showed insufficient foot microvascular autoregulation, eNOS phosphorylation, and NO production with downregulated CaM expression in the arterial endothelium, and abnormal CALM1 transcription in genome-wide sequencing analysis. Therefore, our findings demonstrated that downregulated CaM expression is responsible for endothelium dysfunction and angiogenesis impairment in diabetes, and provided a novel mechanism and target to protect against diabetic endothelial injury.
内皮功能障碍是糖尿病心血管发病机制的核心标志，其特征为内皮型一氧化氮合酶 (eNOS) 和一氧化氮生物利用度受损。然而，其潜在机制尚不清楚。在本研究中，我们旨在确定钙调蛋白 (CaM) 在糖尿病 eNOS 功能障碍中的作用。高糖 (HG) 处理的人脐静脉内皮细胞和小鼠内皮祖细胞 (EPC) 表现出 CaM mRNA/蛋白和血管内皮生长因子 (VEGF) 表达下调，同时 eNOS 磷酸化和细胞迁移/管形成受阻。这些改变在 CALM1 敲低细胞中重现，但在 CALM1 过表达细胞中被阻止。2 型糖尿病动物的 EPC 表现出与 HG 处理的正常 EPC 相似的行为，这可以通过 CALM1 基因转导来挽救。一致地，糖尿病动物表现出 eNOS 磷酸化、内皮依赖性扩张和主动脉 CaM 表达受损，以及腓肠肌中 CaM 和 eNOS 的物理相互作用缺陷。局部 CALM1 基因递送至糖尿病小鼠缺血后肢可改善肢体血液灌注和腓肠肌血管生成受损以及足部损伤。糖尿病患者表现出足部微血管自动调节不足、eNOS 磷酸化和 NO 产生减少，动脉内皮 CaM 表达下调，以及全基因组测序分析中 CALM1 转录异常。因此，我们的研究结果表明，下调的 CaM 表达是糖尿病内皮功能障碍和血管生成受损的原因，并为保护糖尿病内皮损伤提供了新的机制和靶点。
