Department of Emergency and Organ Transplantation, Section of Internal Medicine, Endocrinology, Andrology and Metabolic Diseases, University of Bari Aldo Moro, Piazza Giulio Cesare, 11, I-70124 Bari, Italy.
Endocrinology. 2012 Dec;153(12):5770-81. doi: 10.1210/en.2012-1461. Epub 2012 Oct 17.
Increased apoptosis of cardiac progenitor cells (CPCs) has been proposed as a mechanism of myocardial damage and dysfunction. Glucagon-like peptide-1 (GLP-1) has been shown to improve heart recovery and function after ischemia and to promote cell survival. The protective effects of GLP-1 on oxidative stress-induced apoptosis were investigated in human CPCs isolated from human heart biopsies. Mesenchymal-type cells were isolated from human heart biopsies, exhibited the marker profile of CPCs, differentiated toward the myocardiocyte, adipocyte, chondrocyte, and osteocyte lineages under appropriate culture conditions, and expressed functional GLP-1 receptors. CPCs were incubated with GLP-1 with or without hydrogen peroxide (H(2)O(2)). Phospho- and total proteins were detected by immunoblotting and immunofluorescence analysis. Gene expression was evaluated by quantitative RT-PCR. The role of the canonical GLP-1 receptor was assessed by using the receptor antagonist exendin(9-39) and receptor-specific silencer small interfering RNAs. Cell apoptosis was quantified by an ELISA assay and by flow cytometry-detected Annexin V. Exposure of CPCs to H(2)O(2) induced a 2-fold increase in cell apoptosis, mediated by activation of the c-Jun N-terminal protein kinase (JNK) pathway. Preincubation of CPCs with GLP-1 avoided H(2)O(2)-triggered JNK phosphorylation and nuclear localization, and protected CPCs from apoptosis. The GLP-1 effects were markedly reduced by coincubation with the receptor antagonist exendin(9-39), small interfering RNA-mediated silencing of the GLP-1 receptor, and pretreatment with the protein kinase A inhibitor H89. In conclusion, activation of GLP-1 receptors prevents oxidative stress-mediated apoptosis in human CPCs by interfering with JNK activation and may represent an important mechanism for the cardioprotective effects of GLP-1.
已有研究提出，心脏祖细胞（CPCs）凋亡增加是心肌损伤和功能障碍的一种机制。胰高血糖素样肽-1（GLP-1）已被证明可改善缺血后心脏的恢复和功能，并促进细胞存活。本研究旨在探讨 GLP-1 对人心脏活检分离的 CPCs 氧化应激诱导凋亡的保护作用。从人心脏活检中分离间充质型细胞，这些细胞表现出 CPCs 的标志物特征，在适当的培养条件下向心肌细胞、脂肪细胞、软骨细胞和成骨细胞谱系分化，并表达功能性 GLP-1 受体。将 CPCs 与 GLP-1 共同孵育或单独孵育过氧化氢（H2O2）。通过免疫印迹和免疫荧光分析检测磷酸化和总蛋白。通过定量 RT-PCR 评估基因表达。通过使用 GLP-1 受体拮抗剂 exendin(9-39)和受体特异性沉默小干扰 RNA 评估经典 GLP-1 受体的作用。通过 ELISA 测定和流式细胞术检测 Annexin V 来定量细胞凋亡。H2O2 暴露可使 CPCs 凋亡增加 2 倍，这是通过激活 c-Jun N 末端蛋白激酶（JNK）途径介导的。CPCs 先用 GLP-1 孵育可避免 H2O2 触发的 JNK 磷酸化和核转位，并防止 CPCs 凋亡。与受体拮抗剂 exendin(9-39)共同孵育、GLP-1 受体小干扰 RNA 介导的沉默以及蛋白激酶 A 抑制剂 H89 预处理均显著减弱 GLP-1 的作用。总之，激活 GLP-1 受体可通过干扰 JNK 激活来防止人 CPCs 发生氧化应激介导的凋亡，这可能是 GLP-1 发挥心脏保护作用的一个重要机制。
