Abstract：
Extracellular vesicles (EVs) derived from Mesenchymal Stromal Cells (MSCs) have shown promising therapeutic potential for multiple diseases, including intervertebral disc degeneration (IDD). Nevertheless, the limited production and unstable quality of EVs hindered the clinical application of EVs in IDD. Selenomethionine (Se-Met), the major form of organic selenium present in the cereal diet, showed various beneficial effects, including antioxidant, immunomodulatory and anti-apoptotic effects. In the current study, Se-Met was employed to treat MSCs to investigate whether Se-Met can facilitate the secretion of EVs by MSCs and optimize their therapeutic effects on IDD. On the one hand, Se-Met promoted the production of EVs by enhancing the autophagy activity of MSCs. On the other hand, Se-Met pretreated MSC-derived EVs (Se-EVs) exhibited an enhanced protective effects on alleviating nucleus pulposus cells (NPCs) senescence and attenuating IDD compared with EVs isolated from control MSCs (C-EVs) in vitro and in vivo. Moreover, we performed a miRNA microarray sequencing analysis on EVs to explore the potential mechanism of the protective effects of EVs. The result indicated that miR-125a-5p is markedly enriched in Se-EVs compared to C-EVs. Further in vitro and in vivo experiments revealed that knockdown of miR-125a-5p in Se-EVs (miRKD-Se-EVs) impeded the protective effects of Se-EVs, while overexpression of miR-125a-5p (miROE-Se-EVs) boosted the protective effects. In conclusion, Se-Met facilitated the MSC-derived EVs production and increased miR-125a-5p delivery in Se-EVs, thereby improving the protective effects of MSC-derived EVs on alleviating NPCs senescence and attenuating IDD.
摘要：
源自间充质基质细胞（MSCs）的细胞外囊泡（EVs）已显示出对多种疾病的有希望的治疗潜力，包括椎间盘退变（IDD）。然而，电动汽车产量有限，质量不稳定，阻碍了电动汽车在IDD中的临床应用。硒蛋氨酸（Se-Met），谷物饮食中有机硒的主要形式，表现出各种有益效果，包括抗氧化剂，免疫调节和抗凋亡作用。在目前的研究中,Se-Met用于治疗MSC以研究Se-Met是否可以促进MSC分泌EV并优化其对IDD的治疗效果。一方面,Se-Met通过增强MSCs的自噬活性促进EV的产生。另一方面,与体外和体内从对照MSC（C-EV）分离的EV相比，Se-Met预处理的MSC衍生的EV（Se-EV）对减轻髓核细胞（NPC）衰老和减轻IDD表现出增强的保护作用。此外，我们对EV进行了miRNA微阵列测序分析,以探索EV保护作用的潜在机制.结果表明,与C-EV相比,miR-125a-5p在Se-EV中显著富集。进一步的体外和体内实验表明，Se-EV（miRKD-Se-EV）中miR-125a-5p的敲低阻碍了Se-EV的保护作用，而miR-125a-5p（miROE-Se-EV）的过表达增强了保护作用。总之,Se-Met促进了MSC衍生的EV的产生，并增加了Se-EV中miR-125a-5p的递送，从而提高MSC衍生的EV对减轻NPC衰老和减轻IDD的保护作用。
