The Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan People's Hospital, B24 Yinquan South Road, Qingyuan, 511518, Guangdong, China.
The Key Laboratory of Pathobiology, Department of Pathology, College of Basic Medical Sciences, Jilin University, Ministry of Education, Changchun, 130021, China.
Stem Cell Res Ther. 2022 Aug 3;13(1):394. doi: 10.1186/s13287-022-03100-x.
Retinitis pigmentosa is a rod-cone degenerative disease that induces irreversible vision loss. This study probed the protective capacity of mesenchymal stem cell-derived small EVs (MSC-EVs) on the retinas of rd10 mice and the underlying mechanism.
MSC-EVs were injected into the vitreous of rd10 mice at postnatal day 14 and P21; morphology and function were examined at P28. The mechanism of action was explored by using co-culture of photoreceptor cell line 661 W and microglia cell line BV2.
Treatment with MSC-EVs increased the survival of photoreceptors and preserved their structure. Visual function, as reflected by optomotor and electroretinogram responses, was significantly enhanced in MSC-EVs-treated rd10 mice. Mechanistically, staining for Iba1, GFAP, F4/80, CD68 and CD206 showed that MSC-EVs suppressed the activation of microglial, Müller glial and macrophages. Furthermore, western blotting showed that the treatment inhibited the NF-κB pathway. RNA-seq and qPCR showed that MSC-EVs upregulated anti-inflammatory cytokines while downregulating pro-inflammatory cytokines. MSC-EVs application in vitro decreased the number of TUNEL-positive 661 W cells co-cultured with LPS-stimulated BV2, with similar impact on the cytokine expression as in vivo study. Genetic screening predicted miR-146a to be the downstream target of MSC-EVs, which was detected in MSC-EVs and upregulated in co-cultured 661 W cells and BV2 cells after MSC-EVs treatment. Upregulation of miR-146a by using its mimic decreased the expression of the transcription factor Nr4a3, and its downregulation inhibition promoted Nr4a3 expression in both 661 W and BV2 cells. Nr4a3 was further identified as the target gene of miR-146a by dual-luciferase assay. Furthermore, overexpressing miR-146a significantly decreased the expression of LPS-induced pro-inflammatory cytokines in BV2 cells.
MSC-EVs delays retinal degeneration in rd10 mice mainly by its anti-inflammatory effect via the miR-146a-Nr4a3axis. Hence, MSC-EVs may be used in the treatment of neurodegenerative diseases.
色素性视网膜炎是一种 rod-cone 退行性疾病，可导致不可逆转的视力丧失。本研究探讨了间充质干细胞衍生的小细胞外囊泡（MSC-EVs）对 rd10 小鼠视网膜的保护作用及其机制。
在 rd10 小鼠出生后第 14 天和第 21 天玻璃体腔注射 MSC-EVs；在第 28 天检查形态和功能。通过共培养光感受器细胞系 661 W 和小胶质细胞系 BV2 来探索作用机制。
用 MSC-EVs 处理可增加光感受器的存活率并保持其结构。MSC-EVs 处理的 rd10 小鼠的光感受器运动和视网膜电图反应的视觉功能明显增强。在机制上，Iba1、GFAP、F4/80、CD68 和 CD206 的染色表明 MSC-EVs 抑制了小胶质细胞、Müller 胶质细胞和巨噬细胞的激活。此外，Western blot 显示，该治疗抑制了 NF-κB 通路。RNA-seq 和 qPCR 显示，MSC-EVs 上调了抗炎细胞因子，同时下调了促炎细胞因子。MSC-EVs 在体外应用可减少与 LPS 刺激的 BV2 共培养的 TUNEL 阳性 661 W 细胞的数量，对细胞因子表达的影响与体内研究相似。遗传筛选预测 miR-146a 是 MSC-EVs 的下游靶标，在 MSC-EVs 中检测到，并在 MSC-EVs 处理后共培养的 661 W 细胞和 BV2 细胞中上调。使用其模拟物上调 miR-146a 可降低转录因子 Nr4a3 的表达，而下调 miR-146a 的表达可促进 661 W 和 BV2 细胞中 Nr4a3 的表达。双荧光素酶测定进一步鉴定 miR-146a 是 Nr4a3 的靶基因。此外，过表达 miR-146a 可显著降低 LPS 诱导的 BV2 细胞中促炎细胞因子的表达。
MSC-EVs 通过 miR-146a-Nr4a3 轴主要通过其抗炎作用延缓 rd10 小鼠的视网膜变性。因此，MSC-EVs 可用于治疗神经退行性疾病。
