Division of Cardiovascular Surgery and Toronto General Research Institute, University Health Network, University of Toronto, Ontario, Canada.
Am J Pathol. 2012 Dec;181(6):2067-78. doi: 10.1016/j.ajpath.2012.08.021. Epub 2012 Sep 29.
Autologous stem cell therapy has not been as effective as forecasted from preclinical studies. Patient age was reported as an important contributing factor. The goal of this study was to uncover age-dependent mechanisms of stem cell dysfunction and to investigate possible means to restore the cellular function. Bone marrow mesenchymal stem cells (MSCs) were isolated from cardiovascular patients. Cell proliferation and number of colonies were inversely correlated with patient age. Myogenic differentiation of MSCs in culture was induced with 5-azacytidine. Differentiation correlated with age, with less differentiation in MSCs from aged patients. We performed real-time PCR to identify genes in the WNT/β-catenin signaling network and found that transcript levels of CTNNB1, LEF1, FZD8, WNT3A, and SFRP4 were negatively correlated with age, whereas FOSL1, LRP6, and FZD6 were positively correlated with age. Protein evaluation showed that β-catenin nuclear translocation correlated with age and was lower in aged MSCs. Aged MSCs treated with lithium chloride-to increase the bioavailability of β-catenin-recovered their capacity for myogenic differentiation through myocyte enhancer factor 2C but not with the knockdown of β-catenin using small-interfering RNA. This study may be the first to relate reduced nuclear β-catenin bioavailability in MSCs from aged patients. Most important, this abnormality was potentially recoverable, providing a target for improving the function of bone marrow stem cells and their clinical utility in aged patients.
自体干细胞治疗的效果不如临床前研究预测的那样有效。患者年龄被报道为一个重要的影响因素。本研究的目的是揭示与年龄相关的干细胞功能障碍机制，并研究可能恢复细胞功能的方法。从心血管病患者中分离出骨髓间充质干细胞（MSCs）。细胞增殖和集落数量与患者年龄呈负相关。用 5-氮杂胞苷诱导 MSCs 在培养中的成肌分化。分化与年龄相关，老年患者的 MSCs 分化较少。我们进行实时 PCR 以鉴定 WNT/β-catenin 信号网络中的基因，发现 CTNNB1、LEF1、FZD8、WNT3A 和 SFRP4 的转录水平与年龄呈负相关，而 FOSL1、LRP6 和 FZD6 与年龄呈正相关。蛋白评估表明β-catenin 核易位与年龄相关，并且在老年 MSCs 中较低。用氯化锂处理老年 MSCs 以增加β-catenin 的生物利用度，通过肌细胞增强因子 2C 恢复其成肌分化能力，但使用小干扰 RNA 敲低β-catenin 则不行。这项研究可能是第一个将减少的核β-catenin 生物利用度与老年患者的 MSCs 相关联的研究。最重要的是，这种异常是可以恢复的，为改善骨髓干细胞的功能及其在老年患者中的临床应用提供了一个目标。
