Department of Medicine, Mackay Medical College , New Taipei City, 252, Taiwan.
Graduate Institute of Medical Genomics and Proteomics, College of Medicine, National Taiwan University , Taipei, 100, Taiwan.
J Proteome Res. 2017 Oct 6;16(10):3504-3513. doi: 10.1021/acs.jproteome.7b00148. Epub 2017 Sep 13.
Diabetic cardiomyopathy is a well-recognized complication of diabetes, but its pathophysiology is unclear. We aimed to investigate the mechanisms underlying cardiac dysfunction in an elderly type 2 diabetic (T2DM) mouse model, using membrane proteomic analyses. Elderly mice were fed a high fat diet for 12 weeks to induce T2DM, and myocardial structure and function were assessed by echocardiography. Cardiomyocytes were isolated by Langendorff perfusion and subjected to iTRAQ-based quantitative membrane proteomic profiling, immunoblotting, and real-time quantitative reverse-transcriptase polymerase chain reaction. Compared to controls, elderly T2DM mice showed worse systolic function, more myocardial fibrosis and up-regulation of several heart failure markers (all p < 0.05). Cardiomyocyte membrane proteomic profiling revealed that 417 proteins had differential expressions related to perturbations in several biological processes in T2DM mice compared with the control. The most up-regulated proteins were involved in oxidative phosphorylation, whereas many down-regulated proteins were involved in cytoskeletal regulation. Differential protein expression correlated with myocardial systolic velocity by tissue Doppler. In addition, cardiomyocyte immunofluorescence staining showed greater disorganization of thick/parallel F-actin stress fibers and marked reduction in F-to-G-actin ratio in T2DM vs control (p < 0.05), which paralleled worsened myocardial systolic velocity. We concluded that cardiac contractile dysfunction in elderly T2DM mice was associated with impaired energetics and cytoskeletal disorganization.
糖尿病性心肌病是糖尿病的一种公认并发症，但其病理生理学机制尚不清楚。我们旨在通过膜蛋白质组学分析研究老年 2 型糖尿病（T2DM）小鼠模型中心脏功能障碍的发生机制。老年小鼠用高脂肪饮食喂养 12 周以诱导 T2DM，并通过超声心动图评估心肌结构和功能。通过 Langendorff 灌注分离心肌细胞，并进行 iTRAQ 定量膜蛋白质组学分析、免疫印迹和实时定量逆转录聚合酶链反应。与对照组相比，老年 T2DM 小鼠表现出更差的收缩功能、更多的心肌纤维化和几种心力衰竭标志物的上调（均 p < 0.05）。心肌细胞膜蛋白质组学分析显示，与对照组相比，T2DM 小鼠中有 417 种蛋白质的表达与几种生物学过程的改变相关。上调最明显的蛋白质与氧化磷酸化有关，而下调最明显的蛋白质与细胞骨架调节有关。差异蛋白表达与组织多普勒心肌收缩速度相关。此外，心肌细胞免疫荧光染色显示 T2DM 组的厚/平行 F-肌动蛋白应力纤维的排列更紊乱，F-肌动蛋白到 G-肌动蛋白的比例明显降低（p < 0.05），这与心肌收缩速度的恶化相平行。我们得出结论，老年 T2DM 小鼠的心脏收缩功能障碍与能量代谢受损和细胞骨架紊乱有关。
