Department of Lung Cancer Surgery, Tianjin Medical University General Hospital; Anshan Road No.154, Heping District, Tianjin 300052, China.
Department of Pediatric Surgery, Tianjin Children's Hospital, No.238 LongYan Road, Tianjin 300134, China.
Transpl Immunol. 2023 Jun;78:101806. doi: 10.1016/j.trim.2023.101806. Epub 2023 Mar 15.
Bronchiolitis obliterans syndrome (BOS), induced by a chronic rejection, remains a significant obstacle for end-stage lung diseases after lung transplantation. We have previously determined that the small non-coding mRNA (miRNA) miR-27a-3p maintained the immature state of dendritic cells (DCs) via the interleukin 10 (IL-10)-dependent regulatory pathway. Such status helped in preventing rejection and alleviating BOS. The present study explored mechanisms how miR-27a-3p may suppress the fibrosis as well as the maturation of DCs, ultimately attenuating BOS in vitro and in vivo.
METHODS/RESULTS: In our tracheal transplantation mouse model, the expression of Smad2, Smad4, and αSMA were significantly decreased in the miR-27a-3p-transfected DCs (p < 0.0001, p = 0.0006, and p = 0.0002 respectively). Moreover, the expression of fibrosis markers (α-SMA, collagen I, and Fn) were potently inhibited in the miR-27a-3p-transfected NIH-3 T3 cells (p < 0.0001, p = 0.00148, and p < 0.0001 respectively). At the same time, reversed results were observed in the inhibitor group (p = 0.0002, p < 0.0001, and p < 0.0001 respectively), indicating that miR-27a-3p could directly inhibit myofibroblast differentiation. Furthermore, in the tracheal transplanted mice, the population of Treg cells was significantly decreased (p < 0.0001). In contrast, Th17 cells were down-regulated in the miR-27a-3p-transfected DCs group (p < 0.0001), accompanied by the decreased IL-17 levels (p = 0.0007) and the induction of TGF-β1 and IL-10 (p < 0.0001 and p = 0.0016 respectively). Further mechanistic studies indicated that miR-27a-3p altered the maturation of DCs by targeting TLR4 and IRAK (p < 0.0001 and p = 0.0002 respectively).
Our study suggests that miR-27a-3p selectively blocked the TGF-β1/Smad pathways to suppress the myofibroblast differentiation and targeted the TRL4/IRAK4 pathway to restrain DCs maturation, thus attenuating BOS. Our findings suggest that miR-27a-3p is a potential active molecule on BOS management after lung transplantation.
由慢性排斥反应引起的闭塞性细支气管炎综合征（BOS）仍然是肺移植后晚期肺病的一个重大障碍。我们之前已经确定，小非编码信使 RNA（miRNA）miR-27a-3p 通过白细胞介素 10（IL-10）依赖性调节途径维持树突状细胞（DC）的不成熟状态。这种状态有助于预防排斥反应和减轻 BOS。本研究探讨了 miR-27a-3p 如何抑制纤维化和 DC 成熟，从而在体外和体内减轻 BOS 的机制。
方法/结果：在我们的气管移植小鼠模型中，转染 miR-27a-3p 的 DCs 中 Smad2、Smad4 和 αSMA 的表达明显降低（p<0.0001，p=0.0006 和 p=0.0002）。此外，转染 miR-27a-3p 的 NIH-3T3 细胞中纤维化标志物（α-SMA、胶原 I 和 Fn）的表达也被强烈抑制（p<0.0001，p=0.00148 和 p<0.0001）。同时，在抑制剂组中观察到相反的结果（p=0.0002，p<0.0001 和 p<0.0001），表明 miR-27a-3p 可以直接抑制肌成纤维细胞分化。此外，在气管移植的小鼠中，Treg 细胞的数量明显减少（p<0.0001）。相反，在转染 miR-27a-3p 的 DCs 组中，Th17 细胞的表达下调（p<0.0001），同时 IL-17 水平降低（p=0.0007），TGF-β1 和 IL-10 的诱导增加（p<0.0001 和 p=0.0016）。进一步的机制研究表明，miR-27a-3p 通过靶向 TLR4 和 IRAK 改变 DCs 的成熟（p<0.0001 和 p=0.0002）。
我们的研究表明，miR-27a-3p 通过选择性阻断 TGF-β1/Smad 途径抑制肌成纤维细胞分化，并靶向 TLR4/IRAK4 途径抑制 DCs 成熟，从而减轻 BOS。我们的发现表明，miR-27a-3p 是肺移植后管理 BOS 的一种有潜力的活性分子。
