Introduction: The role of cardiac microvascular endothelial cells (CMECs) in diabetic cardiomyopathy is not fully understood. We aimed to investigate whether a glucagon receptor (GCGR) monoclonal antibody (mAb) ameliorated diabetic cardiomyopathy and clarify whether and how CMECs participated in the process.
Research design and methods: The db/db mice were treated with GCGR mAb or immunoglobulin G (as control) for 4 weeks. Echocardiography was performed to evaluate cardiac function. Immunofluorescent staining was used to determine microvascular density. The proteomic signature in isolated primary CMECs was analyzed by using tandem mass tag-based quantitative proteomic analysis. Some target proteins were verified by using western blot.
Results: Compared with db/m mice, cardiac microvascular density and left ventricular diastolic function were significantly reduced in db/db mice, and this reduction was attenuated by GCGR mAb treatment. A total of 199 differentially expressed proteins were upregulated in db/db mice versus db/m mice and downregulated in GCGR mAb-treated db/db mice versus db/db mice. The enrichment analysis demonstrated that fatty acid β-oxidation and mitochondrial fusion were the key pathways. The changes of the related proteins carnitine palmitoyltransferase 1B, optic atrophy type 1, and mitofusin-1 were further verified by using western blot. The levels of these three proteins were upregulated in db/db mice, whereas this upregulation was attenuated by GCGR mAb treatment.
Conclusion: GCGR antagonism has a protective effect on CMECs and cardiac diastolic function in diabetic mice, and this beneficial effect may be mediated via inhibiting fatty acid β-oxidation and mitochondrial fusion in CMECs.
介绍:心脏微血管内皮细胞(CMECs)在糖尿病心肌病中的作用尚未完全清楚。我们的目的是研究胰高血糖素受体(GCGR)单克隆抗体(mAb)是否改善了糖尿病心肌病，并阐明CMECs是否以及如何参与这一过程 方法: GCGR mAb或免疫球蛋白G(作为对照)治疗db/db小鼠4周。超声心动图检查以评估心脏功能。免疫荧光染色测定微血管密度。串联质谱标签(TMT)定量蛋白质组学分析分离的原代CMECs中蛋白质组学特征。使用蛋白质印迹验证一些靶蛋白 结果:与db/m小鼠相比，db/db小鼠的心脏微血管密度和左心室舒张功能显著降低，GCGR mAb治疗可减轻这种降低。与db/m小鼠相比，db/db小鼠中共有199个差异表达蛋白(DEP)上调，与db/db小鼠相比，GCGR mAb治疗的db/db小鼠中共有199个差异表达蛋白下调。富集分析表明，脂肪酸β-氧化和线粒体融合是关键途径。蛋白质印迹实验进一步确认存在相关蛋白CPT1B、OPA1和MFN1的变化。db/db小鼠中这三种蛋白质水平上调，而GCGR mAb治疗可减轻这种上调 结论:GCGR拮抗剂对糖尿病小鼠CMECs和心脏舒张功能具有保护作用，这种有益作用可能是通过抑制CMECs中脂肪酸β-氧化和线粒体融合来介导的.
Keywords: 2型糖尿病; cardiac microvascular endothelial cells; fatty acid β-oxidation; glucagon receptor; type 2 diabetes; 心脏微血管内皮细胞; 胰高血糖素受体; 脂肪酸β-氧化.
© 2023 The Authors. Journal of Diabetes published by Ruijin Hospital, Shanghai Jiaotong University School of Medicine and John Wiley & Sons Australia, Ltd.