Department of Endocrinology and Metabolism, Department of Cardiology and Institute of Vascular Medicine, Peking University Third Hospital, Beijing, China.
NHC Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides; Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Beijing Key Laboratory of Cardiovascular Receptors Research, Beijing, China.
J Diabetes. 2023 Dec;15(12):1081-1094. doi: 10.1111/1753-0407.13458. Epub 2023 Aug 19.
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.
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.
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.
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.
心脏微血管内皮细胞（CMECs）在糖尿病心肌病中的作用尚不完全清楚。本研究旨在探讨胰高血糖素受体（GCGR）单克隆抗体（mAb）是否能改善糖尿病心肌病，并阐明 CMECs 是否以及如何参与这一过程。
db/db 小鼠用 GCGR mAb 或免疫球蛋白 G（作为对照）治疗 4 周。行超声心动图检查评估心功能。免疫荧光染色测定微血管密度。采用串联质量标签定量蛋白质组学分析方法分析分离的原代 CMECs 中的蛋白质组特征。采用 Western blot 验证部分靶蛋白。
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明显降低，而 GCGR mAb 治疗可减轻这种降低。与 db/m 小鼠相比，db/db 小鼠中有 199 种差异表达蛋白上调，而在 GCGR mAb 治疗的 db/db 小鼠中下调。富集分析表明，脂肪酸β氧化和线粒体融合是关键途径。进一步通过 Western blot 验证了相关蛋白肉碱棕榈酰转移酶 1B、视神经萎缩 1 型和线粒体融合蛋白 1 的变化。这三种蛋白在 db/db 小鼠中表达上调，而 GCGR mAb 治疗可减轻这种上调。
GCGR 拮抗作用对糖尿病小鼠的 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 中的脂肪酸β氧化和线粒体融合来介导的。
