Institute of Clinical Medicine, National Yang-Ming University, Taipei 112, Taiwan, ROC.
Department of Orthopaedics and Traumatology, Taipei Veterans General Hospital, Taipei 112, Taiwan, ROC.
Stem Cell Reports. 2014 Dec 9;3(6):975-86. doi: 10.1016/j.stemcr.2014.10.002. Epub 2014 Nov 6.
Many cell therapies currently being tested are based on mesenchymal stromal cells (MSCs). However, MSCs start to enter the senescent state upon long-term expansion. The role of retinoblastoma (RB) protein in regulating MSC properties is not well studied. Here, we show that RB levels are higher in early-passage MSCs compared with late-passage MSCs. RB knockdown induces premature senescence and reduced differentiation potentials in early-passage MSCs. RB overexpression inhibits senescence and increases differentiation potentials in late-passage MSCs. Expression of DNMT1, but not DNMT3A or DNMT3B, is also higher in early-passage MSCs than in late-passage MSCs. Furthermore, DNMT1 knockdown in early-passage MSCs induces senescence and reduces differentiation potentials, whereas DNMT1 overexpression in late-passage MSCs has the opposite effect. These results demonstrate that RB expressed in early-passage MSCs upregulates DNMT1 expression and inhibits senescence in MSCs. Therefore, genetic modification of RB could be a way to improve the efficiency of MSCs in clinical use.
许多目前正在测试的细胞疗法都基于间充质基质细胞（MSCs）。然而，MSCs 在长期扩增后会开始进入衰老状态。视网膜母细胞瘤（RB）蛋白在调节 MSC 特性方面的作用尚未得到很好的研究。在这里，我们表明 RB 水平在早期传代 MSC 中高于晚期传代 MSC。RB 敲低会诱导早期传代 MSC 过早衰老和分化潜能降低。RB 过表达抑制晚期传代 MSC 的衰老并增加其分化潜能。早期传代 MSC 中 DNMT1 的表达也高于晚期传代 MSC，而 DNMT3A 或 DNMT3B 的表达则没有差异。此外，早期传代 MSC 中 DNMT1 的敲低会诱导衰老并降低分化潜能，而晚期传代 MSC 中 DNMT1 的过表达则有相反的效果。这些结果表明，早期传代 MSC 中表达的 RB 上调了 DNMT1 的表达并抑制了 MSC 的衰老。因此，RB 的基因修饰可能是提高 MSC 在临床应用中效率的一种方法。
