1 Otorhinolaryngology Hospital, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.
2 Centre for Stem Cell Clinical Research and Application, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.
Cell Transplant. 2018 Mar;27(3):571-583. doi: 10.1177/0963689718767159. Epub 2018 May 28.
Airway epithelial cell injury is a key triggering event to activate allergic airway inflammation, such as asthma. We previously reported that administration of mesenchymal stem cells (MSCs) significantly alleviated allergic inflammation in a mouse model of asthma, and the mmu-miR-21/ACVR2A axis may be involved. However, whether MSCs protect against bronchial epithelial cell injury induced by hypoxia, and the underlying mechanism, remain unknown. In our study, the human bronchial epithelial cell line BEAS-2B was induced to undergo apoptosis with a hypoxia mimic of cobalt chloride (CoCl) damage. Treatment of MSCs derived from induced pluripotent stem cells (iPSCs) significantly decreased apoptosis of BEAS-2B cells. There was high miR-21 expression in injured BEAS-2B cells after MSC treatment. Transfection of the miR-21 mimic significantly decreased apoptosis of BEAS-2B, and transfection of a miR-21 inhibitor significantly increased apoptosis. More importantly, the protective effects of MSCs on injured BEAS-2B were reversed by transfection of the miR-21 inhibitor. Binding sites of human miR-21 were identified in the 3'UTR of human ACVR2A. We further determined that CoCl stimulation increased ACVR2A expression at both the mRNA and protein levels. Moreover, transfection of the miR-21 mimic further up-regulated ACVR2A expression induced by CoCl, whereas transfection of the miR-21 inhibitor down-regulated ACVR2A expression. In addition, MSCs increased ACVR2A expression in BEAS-2B cells; however, this effect was reversed after transfection of the miR-21 inhibitor. Our data suggested that MSCs protect bronchial epithelial cells from hypoxic injury via miR-21, which may represent an important target. These findings suggest the potentially wide application of MSCs for epithelial cell injury during hypoxia.
气道上皮细胞损伤是激活过敏性气道炎症（如哮喘）的关键触发事件。我们之前报道过，间充质干细胞（MSCs）的给药显著缓解了哮喘小鼠模型中的过敏炎症，并且 mmu-miR-21/ACVR2A 轴可能参与其中。然而，MSCs 是否可以防止低氧诱导的支气管上皮细胞损伤，以及潜在的机制，仍不清楚。在我们的研究中，使用钴氯化物（CoCl）损伤模拟物诱导人支气管上皮细胞系 BEAS-2B 发生凋亡。来自诱导多能干细胞（iPSCs）的 MSC 处理显著降低了 BEAS-2B 细胞的凋亡。在 MSC 处理后，受损的 BEAS-2B 细胞中 miR-21 表达水平升高。miR-21 模拟物的转染显著降低了 BEAS-2B 的凋亡，而 miR-21 抑制剂的转染则显著增加了凋亡。更重要的是，miR-21 抑制剂的转染逆转了 MSCs 对受损 BEAS-2B 的保护作用。人类 miR-21 的结合位点在人类 ACVR2A 的 3'UTR 中被鉴定出来。我们进一步确定 CoCl 刺激增加了 ACVR2A 在 mRNA 和蛋白质水平上的表达。此外，miR-21 模拟物的转染进一步上调了 CoCl 诱导的 ACVR2A 表达，而 miR-21 抑制剂的转染下调了 ACVR2A 表达。此外，MSCs 增加了 BEAS-2B 细胞中 ACVR2A 的表达；然而，这种效应在 miR-21 抑制剂转染后被逆转。我们的数据表明，MSCs 通过 miR-21 保护支气管上皮细胞免受低氧损伤，这可能是一个重要的靶点。这些发现表明，MSCs 在低氧期间对上皮细胞损伤具有潜在的广泛应用。
