Wu Yuquan, Xu Juan, Xu Jing, Cheng Jun, Jiao Demin, Zhou Chun, Dai Yi, Chen Qingyong
The First Affiliated Hospital of Wenzhou Medical University.
Department of Geriatrics, the 117th Hospital of the Chinese People's Liberation Army (PLA).
Tohoku J Exp Med. 2017 Jun;242(2):129-136. doi: 10.1620/tjem.242.129.
MicroRNAs (miRNAs) are short noncoding RNA that participate in posttranscriptional gene regulation. However, little is understood about the roles of miRNAs in Alzheimer's disease (AD). In this study, we used next-generation sequencing on RNA extracted from the serum samples of 20 AD patients and 20 controls, yielding a total of 72 miRNAs with significantly changed expression levels. Among these candidates, we selected 9 miRNAs with most significant alteration in disease, and validated their expression levels using RT-qPCR analysis on serum samples from 45 AD patients and 40 control subjects. Thus, the serum levels of miR-146a-5p, 106b-3p, 195-5p, 20b-5p, and 497-5p were significantly higher, while those of miR-125b-3p, 29c-3p, 93-5p and 19b-3p were significantly lower in AD patients, compared with control subjects. Two miRNAs, miR-29c-3p and miR-19b-3p, were selected because both RNA deep-sequencing and q-PCR methods indicated lower serum levels of these miRNAs in AD patients. Computational analysis predicted that 3'-untranslated region of signal transduction and activator of transcription 3 (STAT3) mRNA is targeted both by miR-29c-3p and miR-19b-3p. Using SH-SY5Y human neuroblastoma cells, we showed that transfection with miR-29c-3p or miR-19b-3p inhibitor significantly increased STAT3 phosphorylation. Furthermore, Water maze test, which assesses the learning and memory deficits in rodents, showed that escape latency was significantly shorter in AD rats with overexpression of miR-29c-3p or miR-19b-3p than in control AD rats. These results suggest that miR-29c-3p or miR-19b-3p may contribute to the cognitive function. In conclusion, the serum levels of miR-29c-3p and miR-19b-3p are helpful biomarkers for AD.
微小RNA（miRNA）是参与转录后基因调控的短链非编码RNA。然而，人们对miRNA在阿尔茨海默病（AD）中的作用了解甚少。在本研究中，我们对20例AD患者和20例对照者血清样本提取的RNA进行了新一代测序，共得到72个表达水平有显著变化的miRNA。在这些候选miRNA中，我们选择了9个在疾病中变化最显著的miRNA，并通过RT-qPCR分析对45例AD患者和40例对照者的血清样本验证了它们的表达水平。结果显示，与对照者相比，AD患者血清中miR-146a-5p、106b-3p、195-5p、20b-5p和497-5p的水平显著升高，而miR-125b-3p、29c-3p、93-5p和19b-3p的水平显著降低。由于RNA深度测序和q-PCR方法均表明AD患者血清中这两种miRNA水平较低，因此选择了miR-29c-3p和miR-19b-3p这两种miRNA。计算分析预测，信号转导和转录激活因子3（STAT3）mRNA的3'-非翻译区是miR-29c-3p和miR-19b-3p的共同靶点。利用SH-SY5Y人神经母细胞瘤细胞，我们发现转染miR-29c-3p或miR-19b-3p抑制剂可显著增加STAT3磷酸化。此外，评估啮齿动物学习和记忆缺陷的水迷宫试验表明，过表达miR-29c-3p或miR-19b-3p的AD大鼠的逃避潜伏期明显短于对照AD大鼠。这些结果表明，miR-29c-3p或miR-19b-3p可能对认知功能有影响。总之，miR-29c-3p和miR-19b-3p的血清水平是AD的有用生物标志物。
