Liu Dongdong, Pan Jing, Zhao Deyu, Liu Feng
Department of Respiratory Medicine, Children's Hospital of Nanjing Medical UniversityNanjing, China.
Department of Pediatrics, The First Affiliated Hospital of Nanjing Medical UniversityNanjing, China.
Am J Transl Res. 2018 Mar 15;10(3):744-752. eCollection 2018.
Asthma is a wide-spread disease that significantly impacts health throughout the world. A key aspect of the pathology of the disease is the remodeling of the airways by airway smooth muscle cells (ASMCs). MicroRNAs play an important role in post-transcriptional gene regulation and are involved in numerous biological functions, including those linked to asthma. A large number of microRNAs have been identified and investigated in various cell types to assess their function. In the present study, the role and potential mechanisms of miR-223 in ASMCs were investigated. Overexpression of miR-223 was found to induce a phenotypic switch in ASMCs that led to decreased expression of proteins involved in the extracellular matrix, such as α-SMA (ACTA2), and type I and III collagens. Inhibition of miR-223 caused the opposite result. However, unlike mast cells, neither overexpression nor inhibition of miR-223 affected cell viability or apoptosis in ASMCs. To further understand the effects of miR-223 on ASMCs, we applied bioinformatics analysis using predictive software, in combination with western blotting, to reveal that insulin-like growth factor-1 receptor (IGF-1R) was the functional target of miR-223 that leads to the phenotypic switch of ASMCs. Suppression of luciferase activity in a reporter containing the 3'-untranslated region (3'-UTR) of IGF-1R confirmed that this region is the target for the miRNA. Finally, we showed that miR-223 suppressed IGF-1R expression and decreased downstream phosphorylation of Akt (AKT1) in ASMCs. In conclusion, our data demonstrate that miR-223 exerts an inhibitory effect on the fibrotic phenotypes of ASMCs via the PI3K/Akt signaling pathway and IGF-1R is the likely functional target of the microRNA.
哮喘是一种广泛传播的疾病，对全球健康有重大影响。该疾病病理的一个关键方面是气道平滑肌细胞（ASMCs）对气道的重塑。微小RNA在转录后基因调控中起重要作用，并参与包括与哮喘相关的多种生物学功能。大量微小RNA已在各种细胞类型中被鉴定和研究以评估其功能。在本研究中，研究了miR-223在ASMCs中的作用及潜在机制。发现miR-223的过表达诱导ASMCs发生表型转换，导致参与细胞外基质的蛋白质表达降低，如α-SMA（ACTA2）以及I型和III型胶原蛋白。抑制miR-223则产生相反的结果。然而，与肥大细胞不同，miR-223的过表达或抑制均不影响ASMCs的细胞活力或凋亡。为进一步了解miR-223对ASMCs的影响，我们使用预测软件结合蛋白质印迹进行生物信息学分析，以揭示胰岛素样生长因子-1受体（IGF-1R）是导致ASMCs表型转换的miR-223的功能靶点。含有IGF-1R 3'-非翻译区（3'-UTR）的报告基因中荧光素酶活性的抑制证实该区域是miRNA的靶点。最后，我们表明miR-223抑制ASMCs中IGF-1R的表达并降低Akt（AKT1）的下游磷酸化。总之，我们的数据表明miR-223通过PI3K/Akt信号通路对ASMCs的纤维化表型发挥抑制作用，且IGF-1R可能是该微小RNA的功能靶点。
