Department of Pharmacology, School of Pharmacy, Hubei University of Science and Technology, Xianning, Hubei 437100, China.
Center for Cardiovascular Research and Alternative Medicine, University of Wyoming College of Health Sciences, Laramie, WY 82071, USA.
Oxid Med Cell Longev. 2018 Apr 19;2018:5396806. doi: 10.1155/2018/5396806. eCollection 2018.
Mitochondrial injury and defective autophagy are common in diabetic cardiomyopathy. Recent evidence supports benefits of glucagon-like peptide-1 (GLP-1) agonists exendin-4 (Exe) and liraglutide (LIRA) against diabetic cardiomyopathy. This study was designed to examine the effect of Exe and LIRA on glucose-induced cardiomyocyte and mitochondrial injury, oxidative stress, apoptosis, and autophagy change. Cardiomyocytes isolated from adult mice and H9c2 myoblast cells were exposed to high glucose (HG, 33 mM) with or without Exe or LIRA. Cardiac contractile properties were assessed including peak shortening, maximal velocity of shortening/relengthening (±d/d), time to PS, and time-to-90% relengthening (TR). Superoxide levels, apoptotic proteins such as cleaved caspase-3, Bax, and Bcl-2, and autophagy proteins including Atg5, p62, Beclin-1, LC3B, and mTOR/ULK1 were evaluated using Western blot. Mitochondrial membrane potential (MMP) changes were assessed using JC-1, and autophagosomes were determined using GFP-LC3. Cardiomyocyte exposure to HG exhibited prolonged TR associated with significantly decreased PS and ±d/d, the effects of which were partly restored by GLP-1 agonists, the effects of which were negated by the mTOR activator 3BDO. H9c2 cell exposure to HG showed increased intracellular ROS, apoptosis, MMP loss, dampened autophagy, and elevated p-mTOR and p-ULK1, the effects of which were nullified by the GLP-1 agonists. These results suggested that GLP-1 agonists rescued glucose toxicity likely through induction of mTOR-dependent autophagy.
线粒体损伤和自噬缺陷在糖尿病心肌病中很常见。最近的证据支持胰高血糖素样肽-1（GLP-1）激动剂 exendin-4（Exe）和利拉鲁肽（LIRA）对糖尿病心肌病有益。本研究旨在研究 Exe 和 LIRA 对葡萄糖诱导的心肌细胞和线粒体损伤、氧化应激、细胞凋亡和自噬变化的影响。将成年小鼠和 H9c2 成肌细胞分离的心肌细胞暴露于高葡萄糖（HG，33mM）中，有或没有 Exe 或 LIRA。评估了心肌细胞的收缩特性，包括峰值缩短、缩短/延长的最大速度（±d/d）、PS 时间和 90%复长时间（TR）。使用 Western blot 评估超氧化物水平、凋亡蛋白（如 cleaved caspase-3、Bax 和 Bcl-2）和自噬蛋白（包括 Atg5、p62、Beclin-1、LC3B 和 mTOR/ULK1）。使用 JC-1 评估线粒体膜电位（MMP）变化，并用 GFP-LC3 确定自噬体。心肌细胞暴露于 HG 表现出 TR 延长，与 PS 和±d/d 显著降低相关，这些影响部分被 GLP-1 激动剂恢复，而 mTOR 激活剂 3BDO 则消除了这些影响。H9c2 细胞暴露于 HG 显示细胞内 ROS 增加、凋亡、MMP 丧失、自噬减弱和 p-mTOR 和 p-ULK1 升高，这些影响被 GLP-1 激动剂消除。这些结果表明，GLP-1 激动剂通过诱导 mTOR 依赖性自噬来挽救葡萄糖毒性。
