Hong Guanhao, Zhou Yulan, Yang Shukai, Yan Shouquan, Lu Jiaxu, Xu Bo, Zhan Zeyu, Jiang Huasheng, Wei Bo, Wang Jiafeng
Stem Cell Research and Cellular Therapy Center, Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong 524001, People's Republic of China.
Reproductive Medicine Center, Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong 524001, People's Republic of China.
Stem Cells. 2024 Dec 6;42(12):1055-1069. doi: 10.1093/stmcls/sxae057.
A general decline in the osteogenic differentiation capacity of human bone marrow mesenchymal stem cells (hBMSCs) in the elderly is a clinical consensus, with diverse opinions on the mechanisms. Many studies have demonstrated that metformin (MF) significantly protects against osteoporosis and reduces fracture risk. However, the exact mechanism of this effect remains unclear. In this study, we found that the decreased miR-181a-5p expression triggered by MF treatment plays a critical role in recovering the osteogenic ability of aging hBMSCs (derived from elderly individuals). Notably, the miR-181a-5p expression in hBMSCs was significantly decreased with prolonged MF (1000 μM) treatment. Further investigation revealed that miR-181a-5p overexpression markedly impairs the osteogenic ability of hBMSCs, while miR-181a-5p inhibition reveals the opposite result. We also found that miR-181a-5p could suppress the protein translation process of plasminogen activator inhibitor-1 (PAI-1), as evidenced by luciferase assays and Western blots. Additionally, low PAI-1 levels were associated with diminished osteogenic ability, whereas high levels promoted it. These findings were further validated in human umbilical cord mesenchymal stem cells (hUCMSCs). Finally, our in vivo experiment with a bone defects rat model confirmed that the agomiR-181a-5p (long-lasting miR-181a-5p mimic) undermined bone defects recovery, while the antagomiR-181a-5p (long-lasting miR-181a-5p inhibitor) significantly promoted the bone defects recovery. In conclusion, we found that MF promotes bone tissue regeneration through the miR-181a-5p/PAI-1 axis by affecting MSC osteogenic ability, providing new strategies for the treatment of age-related bone regeneration disorders.
老年人骨髓间充质干细胞（hBMSCs）成骨分化能力普遍下降是临床共识，但对其机制存在多种观点。许多研究表明，二甲双胍（MF）能显著预防骨质疏松并降低骨折风险。然而，这种作用的确切机制仍不清楚。在本研究中，我们发现MF处理引发的miR-181a-5p表达降低在恢复衰老hBMSCs（源自老年人）的成骨能力中起关键作用。值得注意的是，随着MF（1000μM）处理时间延长，hBMSCs中miR-181a-5p表达显著降低。进一步研究表明，miR-181a-5p过表达显著损害hBMSCs的成骨能力，而抑制miR-181a-5p则产生相反结果。我们还发现，miR-181a-5p可抑制纤溶酶原激活物抑制剂-1（PAI-1）的蛋白质翻译过程，荧光素酶检测和蛋白质免疫印迹法证实了这一点。此外，PAI-1水平低与成骨能力减弱相关，而高水平则促进成骨能力。这些发现在人脐带间充质干细胞（hUCMSCs）中得到进一步验证。最后，我们在骨缺损大鼠模型上的体内实验证实，agomiR-181a-5p（长效miR-181a-5p模拟物）会破坏骨缺损修复，而antagomiR-181a-5p（长效miR-181a-5p抑制剂）则显著促进骨缺损修复。总之，我们发现MF通过影响间充质干细胞成骨能力，经由miR-181a-5p/PAI-1轴促进骨组织再生，为治疗与年龄相关的骨再生障碍提供了新策略。
