Pediatric Department, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region 530021, P.R. China.
Int J Mol Med. 2021 Sep;48(3). doi: 10.3892/ijmm.2021.5004. Epub 2021 Jul 19.
Neutrophilic asthma (NA) is a subtype of asthma that responds poorly to corticosteroid treatment. In certain diseases, microRNA (miR)‑29a‑3p is considered to be a key regulatory molecule for remodeling of the extracellular matrix. However, the effect of miR‑29a‑3p on airway remodeling is unknown. The present study aimed to investigate the role of miR‑29a‑3p in NA. A mouse model of NA was established and these animals were compared to normal controls. Both groups of mice were subjected to lung function tests and histopathological analysis. Human bronchial epithelial cells (16HBE) were grown in culture and incubated with secreted protein acidic rich in cysteine (SPARC) and a miR‑29a‑3p mimic. The expression of miR‑29a‑3p, SPARC and epithelial‑mesenchymal transition (EMT)‑related markers were measured using reverse transcription‑quantitative PCR and western blotting. Luciferase reporter assay was performed to identify the direct regulatory relationship between miR‑29a‑3p and SPARC. miR‑29a‑3p expression was significantly decreased, while SPARC expression was increased in the NA mouse model with a phenotype of EMT. Overexpression of SPARC downregulated the expression of E‑cadherin, while it increased the expression of vimentin in 16HBE cells. miR‑29a‑3p administration reversed the SPARC‑induced effects on E‑cadherin and vimentin expression. Luciferase assays confirmed that SPARC was the target gene for miR‑29a‑3p. Furthermore, SPARC overexpression increased the protein expression of phosphorylated (p)‑ERK, while transfection with miR‑29a‑3p mimics significantly inhibited this increase. The data suggested that EMT in the NA mouse model was associated with decreased levels of miR‑29a‑3p and elevated SPARC. Furthermore, SPARC could induce the formation of EMT in 16HBE cells in vitro and this was directly targeted by miR‑29a‑3p and mediated by p‑ERK, suggesting that miR‑29a‑3p may participate in the airway remodeling of NA.
中性粒细胞性哮喘（NA）是一种对皮质类固醇治疗反应不佳的哮喘亚型。在某些疾病中，miRNA（miR）-29a-3p 被认为是细胞外基质重塑的关键调节分子。然而，miR-29a-3p 对气道重塑的影响尚不清楚。本研究旨在探讨 miR-29a-3p 在 NA 中的作用。建立了 NA 小鼠模型，并将这些动物与正常对照组进行比较。两组小鼠均进行肺功能测试和组织病理学分析。培养人支气管上皮细胞（16HBE），并用富含半胱氨酸的酸性分泌蛋白（SPARC）和 miR-29a-3p 模拟物孵育。使用逆转录-定量 PCR 和 Western blot 检测 miR-29a-3p、SPARC 和上皮-间充质转化（EMT）相关标志物的表达。通过荧光素酶报告基因检测鉴定 miR-29a-3p 和 SPARC 之间的直接调控关系。在具有 EMT 表型的 NA 小鼠模型中，miR-29a-3p 的表达显著降低，而 SPARC 的表达增加。SPARC 的过表达下调了 16HBE 细胞中 E-钙粘蛋白的表达，而增加了波形蛋白的表达。miR-29a-3p 给药逆转了 SPARC 诱导的 E-钙粘蛋白和波形蛋白表达的变化。荧光素酶测定证实 SPARC 是 miR-29a-3p 的靶基因。此外，SPARC 的过表达增加了磷酸化（p）-ERK 的蛋白表达，而 miR-29a-3p 模拟物的转染显著抑制了这种增加。数据表明，NA 小鼠模型中的 EMT 与 miR-29a-3p 水平降低和 SPARC 升高有关。此外，SPARC 可在体外诱导 16HBE 细胞中 EMT 的形成，并且该作用可被 miR-29a-3p 直接靶向，并由 p-ERK 介导，提示 miR-29a-3p 可能参与 NA 的气道重塑。
