Abstract

Considering the crucial role of miR-155 in DNA repair regulation, the aim of this study was to evaluate the effect of miR-155 on the expression of DNA repair factors involved in single- and double-strand DNA breaks (SSBs and DSBs) and mismatch repair (MMR) in mesenchymal stem cells (MSCs). MSCs were isolated from the bone marrow of a healthy individual, and then confirmed by their adipogenic/osteogenic differentiation and flow cytometric analysis of surface markers of MSCs (CD105, CD90, and CD73). MSCs transfection by green fluorescent protein (GFP) plasmid bearing miR-155 was verified by fluorescent microscope, and was measured via analyzing the percentage of transfected cells compared to non-transfected by flow cytometry. The expression of miR-155 and mRNAs related to DNA repair response system, i.e. XRCC1, XRCC5, XRCC6, and RAD51, were assessed by real-time PCR. Overexpression of miR-155 in MSCs was significant compared to control (p = 0.034). Increase in the expression of DNA repair genes, including XRCC1, XRCC6, XRCC5, and RAD51 was not significant (p = 0.066, 0.108, 0.092, 0.631, and 0.262, respectively). In conclusion, although the expression of DNA repair genes by miR-155 overexpression was not significant, it has the potential to affect DNA repair genes expression.

中文翻译：

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miR-155对间充质干细胞DNA损伤的影响

摘要

考虑到miR-155在DNA修复调控中的关键作用，本研究的目的是评估miR-155对涉及单链和双链DNA断裂（SSB和DSB）的DNA修复因子表达的影响，以及间充质干细胞（MSC）中的错配修复（MMR）。从健康个体的骨髓中分离出MSC，然后通过它们的成脂/成骨分化和MSC表面标记（CD105，CD90和CD73）的流式细胞术分析进行确认。通过带有荧光显微镜的miR-155绿色荧光蛋白（GFP）质粒对MSCs的转染进行了验证，并通过分析与未转染的流式细胞仪相比转染细胞的百分比进行了测定。与DNA修复反应系统有关的miR-155和mRNA的表达，即XRCC1，XRCC5，XRCC6和RAD51，通过实时PCR进行评估。与对照组相比，MSC中miR-155的过表达显着（p = 0.034）。DNA修复基因（包括XRCC1，XRCC6，XRCC5和RAD51）的表达增加并不显着（分别为p = 0.066、0.108、0.092、0.631和0.262）。总之，尽管miR-155过表达的DNA修复基因的表达并不重要，但它有可能影响DNA修复基因的表达。