Xia Hong-Fei, He Tian-Zhu, Liu Chun-Mei, Cui Yi, Song Pei-Pei, Jin Xiao-Hua, Ma Xu
Reproductive and Genetic Center of National Research Institute for Family Planning, Beijing, China.
Cell Physiol Biochem. 2009;23(4-6):347-58. doi: 10.1159/000218181. Epub 2009 May 6.
MicroRNAs (miRNAs) are small noncoding RNAs whose function as modulators of gene expression is crucial for the proper control of cell growth. Although many microRNAs were found to express in central nervous system (CNS), the role of the regulatory networks in which they are involved and their function in the pathological process of nerve cells are only just emerging. In the present study, the possible mechanisms by which one neuronal miRNAs, miR-125b, affected the growth of nervous cells were investigated using in vitro cell line model.
The expression pattern of miR-125b in ATRA-treated human glioma cell lines was detected by Northern blotting and in situ localization. The effect of miR-125b on the proliferation and apoptosis of human glioma cells was analyzed by MTS assay, TUNEL and Flow cytometry analysis. In addition, the identification of target gene of miR-125b was studied by dual-luciferase activity assay and Immunoblot Analysis.
We found differential expression of miR-125b in 1.0 microM all-trans-retinoic acid (ATRA)-treated human glioma cell lines. Up-regulation of miR-125b partially restored cell viability and inhibited cell apoptosis in U343 cells treated by ATRA. Down-regulation of miR-125b decreased human glioma cells proliferation and enhanced the sensitivity of human glioma cells to ATRA-induced apoptosis. In addition, we found an inverse relationship between the expression of miR-125b and the cell apoptosis-related protein Bcl-2 modifying factor (Bmf), and miR-125b can interact with 3'-untranslated region (UTR) of Bmf.
These findings indicate that overexpression of miR-125b promotes human glioma cell proliferation and inhibits ATRA-induced cell apoptosis and low expression of miR-125b sensitizes cells to ATRA-induced apoptosis. BMF may play an important role in the process of miR-125b influencing cell apoptosis.
微小RNA（miRNA）是一类小的非编码RNA，其作为基因表达的调节因子对于细胞生长的正常调控至关重要。尽管发现许多微小RNA在中枢神经系统（CNS）中表达，但它们所参与的调控网络的作用及其在神经细胞病理过程中的功能才刚刚开始显现。在本研究中，使用体外细胞系模型研究了一种神经元微小RNA miR-125b影响神经细胞生长的可能机制。
通过Northern印迹和原位定位检测miR-125b在全反式维甲酸（ATRA）处理的人胶质瘤细胞系中的表达模式。通过MTS测定、TUNEL和流式细胞术分析miR-125b对人胶质瘤细胞增殖和凋亡的影响。此外，通过双荧光素酶活性测定和免疫印迹分析研究miR-125b靶基因的鉴定。
我们发现在1.0微摩尔全反式维甲酸（ATRA）处理的人胶质瘤细胞系中miR-125b表达存在差异。miR-125b的上调部分恢复了经ATRA处理的U343细胞的细胞活力并抑制了细胞凋亡。miR-125b的下调降低了人胶质瘤细胞的增殖并增强了人胶质瘤细胞对ATRA诱导凋亡的敏感性。此外，我们发现miR-125b的表达与细胞凋亡相关蛋白Bcl-2修饰因子（Bmf）之间存在负相关关系，并且miR-125b可以与Bmf的3'-非翻译区（UTR）相互作用。
这些发现表明，miR-125b的过表达促进人胶质瘤细胞增殖并抑制ATRA诱导的细胞凋亡，而miR-125b的低表达使细胞对ATRA诱导的凋亡敏感。BMF可能在miR-125b影响细胞凋亡的过程中起重要作用。
