Li Wei, Lu Yaojun, Han Ruijuan, Yue Qiang, Song Xiurong, Wang Fei, Wu Rina, Hou Feng, Yang Liu, Xu Lijuan, Zhao Ruiping, Hu Jiang
Department of Cardiology, Baotou Central Hospital, Baotou, China.
Department of institution of Interventional and Vascular surgery, Tongji university, Shanghai, China.
Cell Physiol Biochem. 2018;47(2):579-589. doi: 10.1159/000490012. Epub 2018 May 22.
BACKGROUND/AIMS: The transplantation of cardiac progenitor cells (CPCs) improves neovascularization and left ventricular function after myocardial infarction (MI). The bone morphogenetic protein antagonist Gremlin 2 (Grem2) is required for early cardiac development and cardiomyocyte differentiation. The present study examined the role of Grem2 in CPC differentiation and cardiac repair.
To determine the role of Grem 2 during CPC differentiation, c-Kit+ CPCs were cultured in differentiation medium for different times, and Grem2, Notch1 and Jagged1 expression was determined by RT-PCR and western blotting. Short hairpin RNA was used to silence Grem2 expression, and the expression of cardiomyocyte surface markers was assessed by RT-PCR and immunofluorescence staining. In vivo experiments were performed in a mouse model of left anterior descending coronary artery ligation-induced MI.
CPC differentiation upregulated Grem2 expression and activated the Notch1 pathway. Grem2 knockdown inhibited cardiomyocyte differentiation, and this effect was similar to that of Notch1 pathway inhibition in vitro. Jagged1 overexpression rescued the effects of Grem2 silencing. In vivo, Grem2 silencing abolished the protective effects of CPC injection on cardiac fibrosis and function.
Grem2 regulates CPC cardiac differentiation by modulating Notch1 signaling. Grem2 enhances the protective effect of CPCs on heart function in a mouse model of MI, suggesting its potential as the rapeutic protein for cardiac repair.
背景/目的：心脏祖细胞（CPCs）移植可改善心肌梗死（MI）后的新生血管形成和左心室功能。骨形态发生蛋白拮抗剂Gremlin 2（Grem2）是早期心脏发育和心肌细胞分化所必需的。本研究探讨了Grem2在CPC分化和心脏修复中的作用。
为了确定Grem2在CPC分化过程中的作用，将c-Kit⁺ CPCs在分化培养基中培养不同时间，通过逆转录聚合酶链反应（RT-PCR）和蛋白质免疫印迹法检测Grem2、Notch1和Jagged1的表达。使用短发夹RNA沉默Grem2表达，通过RT-PCR和免疫荧光染色评估心肌细胞表面标志物的表达。在左冠状动脉前降支结扎诱导的MI小鼠模型中进行体内实验。
CPC分化上调Grem2表达并激活Notch1信号通路。Grem2基因敲低抑制心肌细胞分化，且在体外这种作用与Notch1信号通路抑制相似。Jagged1过表达挽救了Grem2沉默的作用。在体内，Grem2沉默消除了CPC注射对心脏纤维化和功能的保护作用。
Grem2通过调节Notch1信号传导来调控CPC向心脏细胞的分化。在MI小鼠模型中，Grem2增强了CPC对心脏功能的保护作用，表明其作为心脏修复治疗性蛋白的潜力。
