Department of Biology, Science Faculty, Istanbul University, 34134 Vezneciler, Istanbul, Turkey.
Koc University Research Centre for Translational Medicine (KUTTAM), Koc University, School of Medicine, Topkapi, Davutpasa Cad. No:4 Zeytinburnu, Istanbul, Turkey.
Cell Commun Signal. 2020 Jun 18;18(1):96. doi: 10.1186/s12964-020-00585-y.
Idiopathic pulmonary fibrosis (IPF) is a complex lung disease, whose build-up scar tissue is induced by several molecules. Gastrin-releasing peptide (GRP) is released from pulmonary neuroendocrine cells, alveolar macrophages, and some nerve endings in the lung. A possible role of GRP in IPF is unclear. We aimed to investigate the fibrotic response to GRP, at the cellular level in MRC5 and A549 cell lines. The proliferative and fibrotic effects of GRP on these cells were evaluated by using BrdU, immunoblotting, immunofluorescence and qRT-PCR for molecules associated with myofibroblast differentiation, TGF-β and Wnt signalling. All doses of GRP increased the amount of BrdU incorporation in A549 cells. In contrast, the amount of BrdU increased in MRC5 cells in the first 24 h, though progressively decreased by 72 h. GRP did not stimulate epithelial-mesenchymal transition in A549 cells, rather, it stimulated the differentiation of MRC5 cells into myofibroblasts. Furthermore, GRP induced gene and protein expressions of p-Smad2/3 and Smad4, and reduced the levels of Smad7 in MRC5 cells. In addition, GRP decreased Wnt5a protein levels and stimulated β-catenin activation by increasing Wnt4, Wnt7a and β-catenin protein levels. GRP caused myofibroblast differentiation by inducing TGF-βand Wnt pathways via paracrine and autocrine signalling in MRC5 cells. In conclusion, GRP may lead to pulmonary fibrosis due to its proliferative and fibrotic effects on lung fibroblasts. The abrogation of GRP-mediated signal activation might be considered as a treatment modality for fibrotic lung diseases. Video Abstract.
特发性肺纤维化（IPF）是一种复杂的肺部疾病，其疤痕组织的形成是由多种分子诱导的。胃泌素释放肽（GRP）由肺神经内分泌细胞、肺泡巨噬细胞和肺部的一些神经末梢释放。GRP 在 IPF 中的可能作用尚不清楚。我们旨在研究 GRP 在 MRC5 和 A549 细胞系中的细胞水平对纤维化的反应。通过 BrdU、免疫印迹、免疫荧光和 qRT-PCR 评估 GRP 对这些细胞的增殖和纤维化作用，用于与肌成纤维细胞分化、TGF-β和 Wnt 信号相关的分子。所有剂量的 GRP 均增加 A549 细胞中 BrdU 掺入的量。相比之下，MRC5 细胞中 BrdU 的量在最初 24 小时增加，但在 72 小时后逐渐减少。GRP 并未刺激 A549 细胞发生上皮-间充质转化，而是刺激 MRC5 细胞向肌成纤维细胞分化。此外，GRP 诱导 MRC5 细胞中 p-Smad2/3 和 Smad4 的基因和蛋白表达，并降低 Smad7 的水平。此外，GRP 通过降低 Wnt5a 蛋白水平和增加 Wnt4、Wnt7a 和 β-连环蛋白蛋白水平来刺激 β-连环蛋白的激活。GRP 通过旁分泌和自分泌信号诱导 TGF-β和 Wnt 途径导致 MRC5 细胞中的肌成纤维细胞分化。总之，GRP 可能由于其对肺成纤维细胞的增殖和纤维化作用而导致肺纤维化。抑制 GRP 介导的信号激活可能被视为治疗纤维化性肺疾病的一种治疗方法。视频摘要。
