过表达Nanog基因的小鼠骨髓间质干细胞对NF-κB表达的影响

Overexpression of Nanog gene in mouse mesenchymal stem cells and its influence on NF-κB expression

摘要:

核因子κB(nuclear factor kappa B，NF-κB) 的激活被认为与中枢神经系统变性疾病的进展有关。新近报告Nanog能抑制NF-κB的表达，为验证这一发现，通过限制性内切酶酶切和基因重组的方法，构建携带Nanog基因的重组慢病毒表达载体质粒pNL-Nanog-IRES2-EGFP，经PCR检测以及测序鉴定后，在脂质体介导下与包装质粒HELPER、包膜质粒VSVG共转染293T细胞包装生产慢病毒。所获慢病毒感染小鼠骨髓间充质干细胞 (mMSCs) 后，Western blotting法检测在mMSCs中Nanog 基因的表达，PCR、Western blotting和免疫细胞化学法检测NF-κB基因的表达。结果显示所克隆的Nanog基因测序结果与GenBank报道序列完全一致。构建的慢病毒载体质粒PNL-Nanog-IRES2-EGFP经Sal I和BamH I双酶切后电泳鉴定正确。所获慢病毒感染mMSCs后荧光激发mMSCs可见绿色荧光，Western blotting检测显示Nanog-mMSCs 组表达Nanog，其他两组基本不表达。RT-PCR和Western blotting检测显示Nanog-mMSCs组的NF-κB表达较空载体-mMSCs组及mMSCs组低，有显著性差异。构建携带Nanog基因慢病毒载体并在小鼠骨髓间质干细胞中成功表达，Nanog基因的表达可抑制NF-κB表达，这结果为神经变性疾病的治疗提供了新思路。

Abstract:

The expression of NF-kB is considered to be involved in the progress of neurodegeneration. It has been reported that Nanog can suppress the expression of NF-kB. To inspect and verify this finding, we constructed lentivirus (LV) vector that overexpressed the Nanog gene, infected mouse mesenchymal stem cells (mMSCs), and examined the influence of Nanog overexpression on NF-kB gene expression. The plasmid pNL-Nanog-IRES2-EGFP was constructed by double digestion and genetic recombination. Sequencing results confirmed that our cloned Nanog gene in the PNL-Nanog-IRES2-EGFP plasmid was consistent with the sequence reported in the GenBank. The three plasmids: pNL-Nanog-IRES2-EGFP, HELPER, and VSVG were cotransfected into 293T cells to produce LV particles. After co-transfection of the three lentiviral plasmids, green fluorescence was observed confirming successful transfection. The mMSCs were infected by the LV and the expression of Nanog was then also verified by the presence of green fluorescence. Nanog expression levels in the mMSCs were examined using Western blotting. Expression of NF-kB was also examined using RT-PCR and Western blotting, and in addition with fluorescent microscope after immunocytochemical staining. The levels of Nanog protein expression in Nanog-mMSCs were significantly increased, and the levels of NF-kB mRNA and protein expression in Nanog-infected mMSCs were significantly lower than those of Mock-mMSCs and the mMSCs control groups. Our findings suggest that mMSCs genetically modified to overexpress Nanog can lead to the suppression of NF-kB expression. This suppression of NF-kB could have important implications for the treatment of neurodegeneration, and hence further scientific investigations of these interactions will have significant impact on future clinical attempts to attenuate disease progression.