Department of Ophthalmology, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, China.
Biomaterials. 2013 Sep;34(28):6717-28. doi: 10.1016/j.biomaterials.2013.05.042. Epub 2013 Jun 13.
With the increasing application of microRNAs (miRNAs) in the treatment and monitoring of different diseases, miRNAs have become an important tool in biological and medical research. Recent studies have proven that miRNAs are involved in the osteogenic differentiation of stem cells. However, few studies have reported the use of miRNA-modified adult stem cells to repair critical-sized defects (CSDs) using tissue engineering technology. It is known that miR-31 is a pleiotropically acting miRNA that inhibits cancer metastasis and targets special AT-rich sequence-binding protein 2 (Satb2) in fibroblasts. However, it is not clear whether the function of miR-31 is to enhance adipose tissue-derived stem cell (ASC) osteogenesis, along with its association with Satb2, during osteogenic differentiation and bone regeneration. In this study, we systematically evaluated the function of miR-31 in enhancing ASC osteogenesis and the therapeutic potential of miR-31-modified ASCs in a rat CSD model with β-tricalcium phosphate (β-TCP) scaffolds. ASCs were treated with lentivirus (Lenti)-miR-31, Lenti-as-miR-31 (antisense) or Lenti-NC (negative control). These genetically modified ASCs were then combined with β-TCP scaffolds to repair CSDs in rats. The results showed that in cultured ASCs in vitro, Lenti-as-miR-31 significantly enhanced osteogenic mRNA and protein expression when compared with the Lenti-NC group. Moreover, we firstly found that a Runt-related transcription factor 2 (Runx2), Satb2 and miR-31 regulatory loop triggered by bone morphogenetic protein-2 (BMP-2) plays an important role in ASCs' osteogenic differentiation and bone regeneration. More importantly, we found that miR-31-knockdown ASCs dramatically improved the repair of CSDs, including increased bone volume, increased bone mineral density (BMD) and decreased scaffold residue in vivo. These data confirm the essential role of miR-31-modified ASCs in osteogenesis in vitro and in vivo.
随着 microRNAs（miRNAs）在治疗和监测不同疾病中的应用不断增加，miRNAs 已成为生物和医学研究中的重要工具。最近的研究证明，miRNAs 参与了干细胞的成骨分化。然而，很少有研究报道使用 miRNA 修饰的成人干细胞，结合组织工程技术，来修复临界尺寸缺陷（CSD）。已知 miR-31 是一种多效作用的 miRNA，可抑制癌症转移，并靶向成纤维细胞中的特殊 AT 富含序列结合蛋白 2（Satb2）。然而，尚不清楚 miR-31 的功能是否是增强脂肪组织来源的干细胞（ASC）的成骨作用，以及在成骨分化和骨再生过程中与 Satb2 的关联。在这项研究中，我们系统地评估了 miR-31 增强 ASC 成骨作用的功能，以及 miR-31 修饰的 ASC 在β-磷酸三钙（β-TCP）支架大鼠 CSD 模型中的治疗潜力。将 ASC 用慢病毒（Lenti）-miR-31、Lenti-as-miR-31（反义）或 Lenti-NC（阴性对照）处理。然后将这些基因修饰的 ASC 与β-TCP 支架结合，以修复大鼠的 CSD。结果表明，在体外培养的 ASC 中，与 Lenti-NC 组相比，Lenti-as-miR-31 显著增强了成骨 mRNA 和蛋白表达。此外，我们首次发现，骨形态发生蛋白-2（BMP-2）触发的 runt 相关转录因子 2（Runx2）、Satb2 和 miR-31 调控环在 ASC 的成骨分化和骨再生中起着重要作用。更重要的是，我们发现 miR-31 敲低的 ASC 可显著改善 CSD 的修复，包括增加骨体积、增加骨密度（BMD）和减少体内支架残留。这些数据证实了 miR-31 修饰的 ASC 在体外和体内成骨中的重要作用。
