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微小RNA(miRNAs)作为强大的基因表达调控子,广泛参与多种生命过程,在细胞衰老进程中的作用也日益受到关注。miR-223是一个典型的抑癌基因,可显著抑制细胞增殖能力。miR-223与阿尔茨海默症、心血管疾病以及类风湿性关节炎等衰老相关疾病的发生发展密切相关。尽管如此,miR-223在细胞衰老进程中的作用及其分子机制尚未见报道。本研究通过连续传代建立了小鼠胚胎成纤维细胞(MEF细胞)的复制性衰老模型,并利用荧光定量qRT-PCR检测发现,miR-223在衰老MEF细胞中的表达水平显著上调。随后,通过转染miR-223模拟物Agomir-223在MEF细胞中过表达miR-223。结果显示,过表达miR-223可显著促进MEF细胞的衰老表型并抑制其增殖能力,而抑制miR-223的表达可延缓MEF细胞的复制性衰老进程。进一步利用生物信息学方法预测,获得多个miR-223的候选衰老相关靶基因,包括Rasa1、Ddit4和Smad1等。然而,双萤光素酶报告系统结果显示,miR-223并不显著影响其萤光强度,表明它们很可能并不是miR-223的下游靶基因。综上所述,miR-223可显著促进MEF细胞复制性衰老,然而其调节细胞衰老进程的分子机制依然有待深入研究。
MicroRNAs (miRNAs), as powerful regulators of gene expression, are widely involved in various life processes and are increasingly gaining attention in the process of cellular senescence. miR-223 is a typical tumor suppressor gene that significantly inhibits cell proliferation. miR-223 is closely related to the development of aging-related diseases such as Alzheimer’s disease, cardiovascular diseases and rheumatoid arthritis. However, the role of miR-223 in cellular senescence and its molecular mechanisms have not been reported yet. In this study, we established a replicative senescence model of mouse embryonic fibroblasts (MEFs) by serial passage and detected the expression of miR-223 in MEF cells by qRT-PCR. Subsequently, miR-223 was overexpressed in MEF cells by transfection of the miR-223 mimic Agomir-223. The results showed that overexpression of miR-223 can significantly promote the aging phenotype of MEF cells and inhibit its proliferation ability, while the inhibition of miR-223 expression can delay MEF cell replication senescence process. Further bioinformatics methods were used to predict the candidate senescence-related target genes of miR-223, including Rasa1, Ddit4 and Smad1. However, the results of the dual luciferase reporter system showed that miR-223 did not significantly affect its fluorescence intensity, indicating that they are probably not downstream targets of miR-223. In summary, miR-223 can significantly promote MEF cell senescence, however, its molecular mechanism of regulating cellular senescence remains to be further studied.