Department of Pediatrics, Shengjing Hospital of China Medical University, 36 Sanhao Street, Shenyang, Liaoning 110004, China.
Biomed Res Int. 2020 Oct 5;2020:7176169. doi: 10.1155/2020/7176169. eCollection 2020.
Bronchopulmonary dysplasia (BPD) is a common and serious complication in premature infants. Lung fibroblasts (LFs) are present in the extracellular matrix and participate in pulmonary development in response to BPD. The aim of this study was to investigate the effect of extracellular signal-regulated kinase (ERK) on LFs cultured from newborn rats. . Primary LFs were isolated and treated with epidermal growth factor (EGF, 20 ng/mL) in the presence or absence of an ERK inhibitor, PD98059 (10 mol/L). Phosphorylated ERK1/2 (p-ERK1/2) protein levels were determined using immunocytochemistry, western blotting, and real-time reverse transcription quantitative (RT-q)PCR. LF proliferation was examined by flow cytometry and a cell counting kit-8 assay. LF transdifferentiation was examined by protein and mRNA expression of -smooth muscle actin (-SMA) by immunocytochemistry, western blotting, and RT-qPCR. LF migration was examined by the transwell method.
Phosphorylated ERK1/2, which was activated by EGF, promoted LF proliferation by accelerating cell-cycle progression from the G1 to S phase. After treatment with PD98059, the expression of p-ERK1/2 in LFs, cellular proliferation, and the percentage of cells in S phase were significantly decreased. Phosphorylated ERK1/2 also promoted the differentiation of LFs into myofibroblasts through increased -SMA synthesis and migration.
The activation of ERK promotes proliferation, transdifferentiation, and migration of lung fibroblasts from newborn rats.
支气管肺发育不良（BPD）是早产儿常见且严重的并发症。肺成纤维细胞（LFs）存在于细胞外基质中，并在 BPD 发生时参与肺发育。本研究旨在探讨细胞外信号调节激酶（ERK）对新生大鼠肺成纤维细胞的影响。
原代 LFs 分离培养，表皮生长因子（EGF，20ng/ml）刺激，同时或不同时给予 ERK 抑制剂 PD98059（10μmol/L）。采用免疫细胞化学、Western blot 和实时 RT-qPCR 检测磷酸化 ERK1/2（p-ERK1/2）蛋白水平。通过流式细胞术和细胞计数试剂盒-8 检测 LF 增殖。通过免疫细胞化学、Western blot 和 RT-qPCR 检测 -平滑肌肌动蛋白（-SMA）的蛋白和 mRNA 表达，检测 LF 转分化。通过 Transwell 法检测 LF 迁移。
EGF 激活的 ERK1/2 通过加速细胞周期从 G1 期向 S 期的进展，促进 LF 增殖。用 PD98059 处理后，LFs 中 p-ERK1/2 的表达、细胞增殖以及 S 期细胞的比例均显著降低。磷酸化 ERK1/2 还通过增加 -SMA 合成和迁移，促进 LFs 向肌成纤维细胞分化。
ERK 的激活促进了新生大鼠肺成纤维细胞的增殖、转分化和迁移。
