Institute of Biomedical Engineering, School of Preclinical and Forensic Medicine, West China Center of Medical Sciences, Sichuan University, Chengdu, 610041 Sichuan, PR China.
Institute of Biomedical Engineering, School of Preclinical and Forensic Medicine, West China Center of Medical Sciences, Sichuan University, Chengdu, 610041 Sichuan, PR China.
Int J Biochem Cell Biol. 2018 Jun;99:125-132. doi: 10.1016/j.biocel.2018.04.004. Epub 2018 Apr 5.
A physical stimuli, it has been reported that cyclic tensile strain can promote bone marrow-derived mesenchymal stem cells (BMSCs) to differentiate into cardiomyocytes, but the underlying mechanisms have been poorly elucidated so far. Here, we used a mimicking loading strain, cyclic biaxial tensile strain (CBTS), and found it can promote BMSCs to differentiate into cardiomyocytes. When the CBTS were loaded, the cells expressed cardiac-specific markers GATA4, TNNT2, MEF-2c, and Cx43, meanwhile we found miR-27a decreased and stem cell factor (SCF) increased. When we overexpressed miR-27a, the cardiac-specific markers were down-regulated; we got the same results when SCF was knocked down by siRNA. Interestingly, we found SCF is a potential target of miR-27a by a bioinformatic analysis. So, we overexpressed miR-27a, and found SCF decreased both in mRNA and protein level. And, When miR-27a was co-transfected with SCF-3'UTR, it significantly reduced the luciferase activity, but not when co-transfected with SCF-3'UTR mutation plasmid. Furthermore, after transfected both miR-27a and SCF siRNA, and the protein expression of the markers were more down-regulated than that of single of them. Taken together, we found CBTS can promote BMSCs to differentiate into cardiomyocytes, and miR-27a functions as a mechano-sensitive miRNA in this process by targeting SCF.
已有报道称，物理刺激，如循环张应变能促进骨髓间充质干细胞（BMSCs）向心肌细胞分化，但目前为止其潜在机制尚未完全阐明。在此，我们采用模拟加载应变，即循环双向张应变（CBTS），发现其能促进 BMSCs 向心肌细胞分化。当加载 CBTS 时，细胞表达心脏特异性标志物 GATA4、TNNT2、MEF-2c 和 Cx43，同时我们发现 miR-27a 下调，干细胞因子（SCF）上调。当我们过表达 miR-27a 时，心脏特异性标志物下调；当用 siRNA 敲低 SCF 时，我们得到了相同的结果。有趣的是，我们通过生物信息学分析发现 SCF 是 miR-27a 的一个潜在靶标。因此，我们过表达 miR-27a，发现 SCF 的 mRNA 和蛋白水平均降低。并且，当 miR-27a 与 SCF-3'UTR 共转染时，其荧光素酶活性显著降低，但与 SCF-3'UTR 突变质粒共转染时则没有。此外，当同时转染 miR-27a 和 SCF siRNA 后，其标志物的蛋白表达比单独转染其中之一时的表达更低。综上所述，我们发现 CBTS 能促进 BMSCs 向心肌细胞分化，而 miR-27a 通过靶向 SCF 作为一种机械敏感性 miRNA 在该过程中发挥作用。
