Rationale Extracellular vesicles (EVs) are small lipid vesicles, and EV-coupled microRNAs (miRNAs) are important modulators of biological processes. Fibrocytes are circulating bone marrow-derived cells that migrate into the injured lungs and contribute to fibrogenesis. The question of whether EV-coupled miRNAs derived from fibrocytes are able to regulate pulmonary fibrosis has not been addressed yet. Methods Pulmonary fibrosis was induced in rats by intratracheal administration of an adenoviral gene vector encoding active transforming growth factor-β1 (TGF-β1) or control vector. Primary fibrocytes and fibroblasts were cultured from rat lungs and were sorted by anti-CD45 magnetic beads. Human circulating fibrocytes and fibrocytes in bronchoalveolar lavage fluid (BALF) were isolated by fibronectin-coated dishes. Fibrocytes were cultured on different stiffness plates or decellularised lung scaffolds. We also determined the effects of extracellular matrix (ECM) and recombinant TGF-β1 on the cellular and EV-coupled miRNA expression of fibrocytes. Results The EVs of fibrocytes derived from fibrotic lungs significantly upregulated the expression of col1a1 of fibroblasts. Culturing on rigid plates or fibrotic decellularised lung scaffolds increased miR-21-5 p expression compared with soft plates or normal lung scaffolds. Dissolved ECM collected from fibrotic lungs and recombinant TGF-β1 increased miR-21-5 p expression on fibrocytes, and these effects were attenuated on soft plates. Fibrocytes from BALF collected from fibrotic interstitial pneumonia patients showed higher miR-21-5 p expression than those from other patients. Conclusions Our results indicate that ECM contributes to fibrogenesis through biomechanical and biochemical effects on miRNA expression in fibrocytes. All data relevant to the study are included in the article or uploaded as supplementary information.

中文翻译：

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纤维化细胞外基质诱导细胞外囊泡与纤维细胞促纤维化 miRNA 的释放

基本原理细胞外囊泡 (EV) 是小脂质囊泡，EV 偶联的 microRNA (miRNA) 是生物过程的重要调节剂。纤维细胞是循环的骨髓衍生细胞，可迁移到受伤的肺部并促进纤维化。来自纤维细胞的 EV 偶联 miRNA 是否能够调节肺纤维化的问题尚未得到解决。方法通过气管内给予编码活性转化生长因子-β1（TGF-β1）的腺病毒基因载体或对照载体，诱导大鼠肺纤维化。从大鼠肺中培养原代成纤维细胞和成纤维细胞，并通过抗 CD45 磁珠进行分类。人循环纤维细胞和支气管肺泡灌洗液 (BALF) 中的纤维细胞通过纤连蛋白涂层培养皿分离。纤维细胞在不同的硬度板或脱细胞肺支架上培养。我们还确定了细胞外基质 (ECM) 和重组 TGF-β1 对纤维细胞的细胞和 EV 偶联 miRNA 表达的影响。结果 来自纤维化肺的纤维细胞的 EVs 显着上调成纤维细胞 col1a1 的表达。与软板或正常肺支架相比，在刚性板或纤维化脱细胞肺支架上培养增加了 miR-21-5 p 的表达。从纤维化肺收集的溶解 ECM 和重组 TGF-β1 增加了纤维细胞上 miR-21-5 p 的表达，并且这些影响在软板上减弱。从纤维化间质性肺炎患者收集的 BALF 中的纤维细胞显示出比其他患者更高的 miR-21-5 p 表达。结论 我们的结果表明，ECM 通过对纤维细胞中 miRNA 表达的生物力学和生化作用促进纤维发生。与研究相关的所有数据都包含在文章中或作为补充信息上传。