Hao Y, Zhu G, Yu L, Ren Z, Zhang P, Zhu J, Cao S
Department of Orthopedics, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, PR China.
Department of Orthopedics, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, PR China.
Osteoarthritis Cartilage. 2022 Nov;30(11):1455-1467. doi: 10.1016/j.joca.2022.08.009. Epub 2022 Aug 27.
Extracellular vesicles released by mesenchymal stem cells (MSC-EVs) can be applied to alleviate intervertebral disc degeneration (IVDD) by curbing apoptosis of nucleus pulposus cells (NPCs). The current study aims to evaluate the effect of MSC-EVs on NPC apoptosis and IVDD and the related regulatory mechanisms involving microRNA (miR)-217.
Expression of miR-217 was examined in tumor necrosis factor-α (TNF-α)-induced NPCs and MSC-EVs, followed by identification in the relationship between miR-217, enhancer of zeste homolog 2 (EZH2) and forkhead box O-3 (FOXO3). After isolation of EVs from MSCs and subsequent co-culture with NPCs, we assessed effects of miR-217 on NPC viability, autophagy, senescence and apoptosis along with extracellular matrix (ECM) degradation. Further in vivo experiments were conducted in rat models of IVDD to substantiate the effect of miR-217 on IVDD.
Poor miR-217 expression was found in TNF-α-induced NPCs, while high miR-217 expression was identified in MSC-EVs (P < 0.05). MSC-EVs transferred miR-217 to NPCs and increased its expression, thus attenuating NPC apoptosis and ECM degradation (elevated collagen II and aggrecan but reduced MMP13 and ADAMTS5) (P < 0.05). miR-217 targeted EZH2, and EZH2 bound to the FOXO3 promoter and consequently downregulated its expression. FOXO3 restrained NPC apoptosis and ECM degradation by stimulating cell autophagy (P < 0.05). Furthermore, in vivo experimental results confirmed the suppressive role of miR-217 shuttled by MSC-EVs in IVDD.
Overall, the delivery of miR-217 may be a novel mechanism underlying the effect of MSC-EVs on NPC apoptosis and ECM degradation following IVDD.
间充质干细胞释放的细胞外囊泡（MSC-EVs）可通过抑制髓核细胞（NPCs）凋亡来减轻椎间盘退变（IVDD）。本研究旨在评估MSC-EVs对NPC凋亡和IVDD的影响以及涉及微小RNA（miR）-217的相关调控机制。
检测肿瘤坏死因子-α（TNF-α）诱导的NPCs和MSC-EVs中miR-217的表达，随后确定miR-217、zeste同源物2增强子（EZH2）和叉头框O-3（FOXO3）之间的关系。从间充质干细胞中分离出细胞外囊泡并随后与NPCs共培养后，我们评估了miR-217对NPC活力、自噬、衰老和凋亡以及细胞外基质（ECM）降解的影响。在IVDD大鼠模型中进行了进一步的体内实验，以证实miR-217对IVDD的作用。
在TNF-α诱导的NPCs中发现miR-217表达较低，而在MSC-EVs中发现miR-217表达较高（P < 0.05）。MSC-EVs将miR-217转移至NPCs并增加其表达，从而减轻NPC凋亡和ECM降解（胶原II和聚集蛋白聚糖升高，但基质金属蛋白酶13和含血小板反应蛋白基序的解聚素样金属蛋白酶5降低）（P < 0.05）。miR-217靶向EZH2，且EZH2与FOXO3启动子结合并因此下调其表达。FOXO3通过刺激细胞自噬抑制NPC凋亡和ECM降解（P < 0.05）。此外，体内实验结果证实了MSC-EVs携带的miR-217在IVDD中的抑制作用。
总体而言，miR-217的传递可能是MSC-EVs对IVDD后NPC凋亡和ECM降解起作用的一种新机制。
