Previous reports have identified that human bone marrow mesenchymal stem cell-derived extracellular vesicles (BMSC-EVs) with their cargo microRNAs (miRNAs) are a promising therapeutic approach for the treatment of idiopathic pulmonary fibrosis (IPF). Therefore, we explored whether delivery of microRNA-186 (miR-186), a downregulated miRNA in IPF, by BMSC EVs could interfere with the progression of IPF in a murine model. In a co-culture system, we assessed whether BMSC-EVs modulated the activation of fibroblasts. We established a mouse model of PF to evaluate the in vivo therapeutic effects of BMSC-EVs and determined miR-186 expression in BMSC-EVs by polymerase chain reaction. Using a loss-of-function approach, we examined how miR-186 delivered by BMSC-EVs affected fibroblasts. The putative relationship between miR-186 and SRY-related HMG box transcription factor 4 (SOX4) was tested using luciferase assay. Next, we investigated whether EV-miR-186 affected fibroblast activation and PF by targeting SOX4 and its downstream gene, Dickkopf-1 (DKK1). BMSC-EVs suppressed lung fibroblast activation and delayed IPF progression in mice. miR-186 was downregulated in IPF but enriched in the BMSC-EVs. miR-186 delivered by BMSC-EVs could suppress fibroblast activation. Furthermore, miR-186 reduced the expression of SOX4, a target gene of miR-186, and hence suppressed the expression of DKK1. Finally, EV-delivered miR-186 impaired fibroblast activation and alleviated PF via downregulation of SOX4 and DKK1. In conclusion, miR-186 delivered by BMSC-EVs suppressed SOX4 and DKK1 expression, thereby blocking fibroblast activation and ameliorating IPF, thus presenting a novel therapeutic target for IPF.

中文翻译：

---

骨髓间充质干细胞胞外囊泡中的 microRNA-186 通过与 SOX4 和 DKK1 相互作用减轻特发性肺纤维化

先前的报道已经确定，人骨髓间充质干细胞衍生的细胞外囊泡 (BMSC-EVs) 及其货物 microRNA (miRNA) 是治疗特发性肺纤维化 (IPF) 的一种有前途的治疗方法。因此，我们探讨了通过 BMSC EV 传递 IPF 中下调的 miRNA 的 microRNA-186 (miR-186) 是否会干扰小鼠模型中 IPF 的进展。在共培养系统中，我们评估了 BMSC-EVs 是否调节了成纤维细胞的活化。我们建立了 PF 小鼠模型来评估 BMSC-EVs 的体内治疗效果，并通过聚合酶链反应确定 BMSC-EVs 中 miR-186 的表达。使用功能丧失方法，我们检查了 BMSC-EV 传递的 miR-186 如何影响成纤维细胞。使用荧光素酶测定法测试了 miR-186 和 SRY 相关的 HMG 盒转录因子 4 (SOX4) 之间的推定关系。接下来，我们研究了 EV-miR-186 是否通过靶向 SOX4 及其下游基因 Dickkopf-1 (DKK1) 影响成纤维细胞活化和 PF。BMSC-EVs 抑制了小鼠肺成纤维细胞的活化并延缓了 IPF 的进展。miR-186 在 IPF 中下调，但在 BMSC-EV 中富集。BMSC-EVs 传递的 miR-186 可以抑制成纤维细胞的活化。此外，miR-186降低了miR-186的靶基因SOX4的表达，从而抑制了DKK1的表达。最后，EV 传递的 miR-186 通过下调 SOX4 和 DKK1 损害成纤维细胞活化并减轻 PF。总之，由 BMSC-EV 传递的 miR-186 抑制了 SOX4 和 DKK1 的表达，