Affiliated Hospital of Jiang nan University, Department of Burn and Plastic Surgery, Wuxi 214000, Jiangsu, China.
The Third People's Hospital of Bengbu Affiliated to Bengbu Medical University, Department of Burn and Plastic Surgery, Bengbu 230000, Anhui, China.
Biomed Environ Sci. 2024 Sep 20;37(9):1030-1043. doi: 10.3967/bes2024.128.
Our previous studies established that microRNA (miR)-451 from human umbilical cord mesenchymal stem cell-derived exosomes (hUC-MSC-Exos) alleviates acute lung injury (ALI). This study aims to elucidate the mechanisms by which miR-451 in hUC-MSC-Exos reduces ALI by modulating macrophage autophagy.
Exosomes were isolated from hUC-MSCs. Severe burn-induced ALI rat models were treated with hUC-MSC-Exos carrying the miR-451 inhibitor. Hematoxylin-eosin staining evaluated inflammatory injury. Enzyme-linked immunosorbnent assay measured lipopolysaccharide (LPS), tumor necrosis factor-α, and interleukin-1β levels. qRT-PCR detected miR-451 and tuberous sclerosis complex 1 (TSC1) expressions. The regulatory role of miR-451 on TSC1 was determined using a dual-luciferase reporter system. Western blotting determined TSC1 and proteins related to the mammalian target of rapamycin (mTOR) pathway and autophagy. Immunofluorescence analysis was conducted to examine exosomes phagocytosis in alveolar macrophages and autophagy level.
hUC-MSC-Exos with miR-451 inhibitor reduced burn-induced ALI and promoted macrophage autophagy. MiR-451 could be transferred from hUC-MSCs to alveolar macrophages exosomes and directly targeted TSC1. Inhibiting miR-451 in hUC-MSC-Exos elevated TSC1 expression and inactivated the mTOR pathway in alveolar macrophages. Silencing TSC1 activated mTOR signaling and inhibited autophagy, while TSC1 knockdown reversed the autophagy from the miR-451 inhibitor-induced.
miR-451 from hUC-MSC exosomes improves ALI by suppressing alveolar macrophage autophagy through modulation of the TSC1/mTOR pathway, providing a potential therapeutic strategy for ALI.
我们之前的研究表明，人脐带间充质干细胞来源的外泌体中的 microRNA（miR）-451 可减轻急性肺损伤（ALI）。本研究旨在阐明 hUC-MSC-Exos 中的 miR-451 通过调节巨噬细胞自噬来减轻 ALI 的机制。
从 hUC-MSCs 中分离出外泌体。用携带 miR-451 抑制剂的 hUC-MSC-Exos 处理严重烧伤诱导的 ALI 大鼠模型。苏木精-伊红染色评估炎症损伤。酶联免疫吸附试验测定脂多糖（LPS）、肿瘤坏死因子-α 和白细胞介素-1β 水平。qRT-PCR 检测 miR-451 和结节性硬化复合物 1（TSC1）的表达。使用双荧光素酶报告系统确定 miR-451 对 TSC1 的调节作用。Western blot 测定 TSC1 及哺乳动物雷帕霉素靶蛋白（mTOR）通路和自噬相关蛋白的表达。免疫荧光分析检测肺泡巨噬细胞中 exosomes 的吞噬作用和自噬水平。
携带 miR-451 抑制剂的 hUC-MSC-Exos 可减轻烧伤诱导的 ALI，并促进巨噬细胞自噬。miR-451 可从 hUC-MSCs 转移到肺泡巨噬细胞的外泌体中，并直接靶向 TSC1。抑制 hUC-MSC-Exos 中的 miR-451 可上调 TSC1 表达并使肺泡巨噬细胞中的 mTOR 通路失活。沉默 TSC1 激活 mTOR 信号并抑制自噬，而 TSC1 敲低可逆转 miR-451 抑制剂诱导的自噬。
hUC-MSC 外泌体中的 miR-451 通过调节 TSC1/mTOR 通路抑制肺泡巨噬细胞自噬，从而改善 ALI，为 ALI 提供了一种潜在的治疗策略。
