Li Tao, Zhao Jiangminghao, Yuan Jinghong, Ding Rui, Yang Guoyu, Cao Jian, Zhao Xiaokun, Liu Jiahao, Liu Yuan, Xu Peichuan, Deng Jianjian, Miao Xinxin, Cheng Xigao
Department of Orthopedics, The Second Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, Jiangxi, China.
Institute of Orthopedics of Jiangxi Province, Nanchang, Jiangxi, 330006, China.
Mater Today Bio. 2025 Mar 20;32:101648. doi: 10.1016/j.mtbio.2025.101648. eCollection 2025 Jun.
Postmenopausal osteoporosis (PMOP), a prevalent skeletal disorder among women post-menopause, has emerged as a pressing global public health concern. Exosomes derived from serum have exhibited encouraging therapeutic potential in addressing PMOP, albeit with underlying mechanisms requiring deeper exploration. To elucidate these mechanisms, we devised a mouse model by surgically inducing ovariectomy and isolated exosomes from serum samples. Subsequently, we employed qRT-PCR, Western blotting, and immunofluorescence analysis to quantify relevant gene and protein expression patterns. To assess the biological effects on treated cells and tissues, we utilized ARS staining, oil red O staining, and micro-CT analysis. Additionally, we examined the METTL3/FOXO1 m6A site interaction and the FOXO1/YTHDF1 complex using dual-luciferase reporter assays and RIP assays. The m6A modification levels of FOXO1 were quantified via MeRIP-PCR. Furthermore, we engineered bone marrow mesenchymal stem cell exosomes by loading abundant METTL3 mRNA and decorating their surfaces with bone-targeting peptides. The successful synthesis and bone-targeting capabilities of these modified exosomes were validated through electron microscopy, imaging, and immunofluorescence staining. Our findings reveal that METTL3, in collaboration with YTHDF1 within serum-derived exosomes, enhances FOXO1 gene transcription by fostering m6A modification of FOXO1. This, in turn, promotes osteogenic differentiation of bone marrow mesenchymal stem cells while inhibiting lipogenic differentiation. Notably, our engineered exosomes, BT-oe-METTL3-EXO, not only harbor high levels of METTL3 but also demonstrate exceptional bone-targeting efficiency. studies demonstrated that BT-oe-METTL3-EXO significantly mitigated bone mass loss induced by ovariectomy in mice, bolstered osteogenic differentiation of mouse bone marrow mesenchymal stem cells, and inhibited lipogenic differentiation. Collectively, our research underscores the pivotal regulatory function of serum-derived exosomes in human bone marrow stem cells (hBMSCs) and underscores the promising therapeutic potential of BT-oe-METTL3-EXO for combating postmenopausal osteoporosis.
绝经后骨质疏松症（PMOP）是一种在绝经后女性中普遍存在的骨骼疾病，已成为全球紧迫的公共卫生问题。血清来源的外泌体在解决PMOP方面显示出令人鼓舞的治疗潜力，尽管其潜在机制仍需深入探索。为了阐明这些机制，我们通过手术诱导卵巢切除构建了小鼠模型，并从血清样本中分离外泌体。随后，我们采用qRT-PCR、蛋白质免疫印迹法和免疫荧光分析来量化相关基因和蛋白质的表达模式。为了评估对处理后的细胞和组织的生物学效应，我们利用了茜素红染色、油红O染色和显微CT分析。此外，我们使用双荧光素酶报告基因检测和RNA免疫沉淀实验来检测METTL3/FOXO1 m6A位点相互作用以及FOXO1/YTHDF1复合物。通过MeRIP-PCR定量FOXO1的m6A修饰水平。此外，我们通过加载大量METTL3 mRNA并用骨靶向肽修饰其表面来改造骨髓间充质干细胞外泌体。通过电子显微镜、成像和免疫荧光染色验证了这些修饰外泌体的成功合成和骨靶向能力。我们的研究结果表明，METTL3与血清来源外泌体中的YTHDF1协同作用，通过促进FOXO1的m6A修饰来增强FOXO1基因转录。这反过来又促进骨髓间充质干细胞的成骨分化，同时抑制脂肪生成分化。值得注意的是，我们改造后的外泌体BT-oe-METTL3-EXO不仅含有高水平的METTL3，而且还表现出卓越的骨靶向效率。研究表明，BT-oe-METTL3-EXO显著减轻了卵巢切除诱导的小鼠骨质流失，促进了小鼠骨髓间充质干细胞的成骨分化，并抑制了脂肪生成分化。总的来说，我们的研究强调了血清来源外泌体在人骨髓干细胞（hBMSCs）中的关键调节功能，并强调了BT-oe-METTL3-EXO在对抗绝经后骨质疏松症方面的潜在治疗前景。
