Department of Orthopedics, The First Affiliated Hospital of Anhui Medical University, No. 218 Jixi Road, Hefei City, Anhui Province 230022, China.
Mediators Inflamm. 2021 Nov 2;2021:9972805. doi: 10.1155/2021/9972805. eCollection 2021.
In the past decade, mesenchymal stem cells (MSCs) have been widely used for the treatment of osteoarthritis (OA), and noncoding RNAs in exosomes may play a major role.
The present study is aimed at exploring the effect and mechanism of miR-326 in exosomes secreted by bone marrow mesenchymal stem cells (BMSCs) on pyroptosis of cartilage and OA improvement.
Exosomes from BMSCs (BMSC-Exos) were isolated and identified to incubate with OA chondrocytes. Proliferation, migration, specific gene and miR-326 expression, and pyroptosis of chondrocytes were detected. BMSCs or chondrocytes were transfected with miR-326 mimics or inhibitors to investigate the effect of miR-326 in BMSC-Exos on pyroptosis of chondrocytes and the potential mechanism. Finally, a rat OA model was established to verify the effect and mechanism of miR-326 in BMSC-Exos on cartilage of pyroptosis.
Incubation with BMSC-Exos could significantly improve the survival rate, migration ability, and chondrocyte-specific genes (COL2A1, SOX9, Agg, and Prg4) and miR-326 expression of OA chondrocytes and significantly inhibit pyroptosis of chondrocytes by downregulation of the levels of inflammatory cytokines, Caspase-1 activity, and pyroptosis-related proteins such as GSDMD, NLRP3, ASC, IL-1, and IL-18 ( < 0.01). PKH26 labeling confirmed the uptake of BMSC-Exos by chondrocytes. Incubation with exosomes extracted from BMSCs overexpressing miR-326 can significantly repress the pyroptosis of chondrocytes, while knockdown of miR-326 had the opposite effect ( < 0.01). The same result was also demonstrated by direct interference with the expression level of miR-326 in chondrocytes ( < 0.01). In addition, we found that the overexpression of miR-326 significantly inhibited the expression of HDAC3 and NF-B p65 and significantly promoted the expression of STAT1, acetylated STAT1, and acetylated NF-B p65 in chondrocytes ( < 0.01). The targeted relationship between miR-326 and HDAC3 was verified by dual-luciferase reporter assay. Animal experiments confirmed the mechanism by which miR-326 delivered by BMSC-Exos inhibits pyroptosis of cartilage by targeting HDAC3 and STAT1/NF-B p65 signaling pathway.
BMSC-Exos can deliver miR-326 to chondrocytes and cartilage and improve OA by targeting HDAC3 and STAT1//NF-B p65 to inhibit pyroptosis of chondrocytes and cartilage. Our findings provide a new mechanism for BMSC-Exos to treat OA.
在过去的十年中，间充质干细胞（MSCs）已被广泛用于治疗骨关节炎（OA），外泌体中的非编码 RNA 可能发挥主要作用。
本研究旨在探讨骨髓间充质干细胞（BMSCs）来源的外泌体中 miR-326 对软骨细胞焦亡和 OA 改善的影响及机制。
分离并鉴定 BMSCs 来源的外泌体（BMSC-Exos），孵育 OA 软骨细胞。检测软骨细胞的增殖、迁移、特异性基因和 miR-326 表达以及焦亡情况。转染 miR-326 模拟物或抑制剂以研究 miR-326 在 BMSC-Exos 对软骨细胞焦亡的影响及其潜在机制。最后，建立大鼠 OA 模型，以验证 miR-326 在 BMSC-Exos 对软骨细胞焦亡的作用和机制。
BMSC-Exos 孵育可显著提高 OA 软骨细胞的存活率、迁移能力和软骨细胞特异性基因（COL2A1、SOX9、Agg 和 Prg4）及 miR-326 的表达，并通过降低炎症细胞因子、Caspase-1 活性以及焦亡相关蛋白（GSDMD、NLRP3、ASC、IL-1 和 IL-18）的水平来显著抑制软骨细胞焦亡（<0.01）。PKH26 标记证实了软骨细胞对 BMSC-Exos 的摄取。孵育过表达 miR-326 的 BMSC 来源的外泌体可显著抑制软骨细胞的焦亡，而敲低 miR-326 则有相反的效果（<0.01）。通过直接干扰软骨细胞中 miR-326 的表达水平也得到了相同的结果（<0.01）。此外，我们发现 miR-326 的过表达可显著抑制软骨细胞中 HDAC3 和 NF-B p65 的表达，同时显著促进 STAT1、乙酰化 STAT1 和乙酰化 NF-B p65 的表达（<0.01）。通过双荧光素酶报告基因实验验证了 miR-326 与 HDAC3 之间的靶向关系。动物实验证实了 BMSC-Exos 通过靶向 HDAC3 和 STAT1/NF-B p65 信号通路抑制软骨细胞焦亡来改善 OA 的机制。
BMSC-Exos 可将 miR-326 递送至软骨细胞和软骨组织，并通过靶向 HDAC3 和 STAT1/NF-B p65 抑制软骨细胞焦亡来改善 OA。我们的研究结果为 BMSC-Exos 治疗 OA 提供了新的机制。
