D1398G Variant of MET Is Associated with Impaired Signaling of Hepatocyte Growth Factor in Alveolar Epithelial Cells and Lung Fibroblasts
D1398G Variant of MET Is Associated with Impaired Signaling of Hepatocyte Growth Factor in Alveolar Epithelial Cells and Lung Fibroblasts
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DOI：
10.1371/journal.pone.0162357
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发表时间：
2016-09-01
期刊：
影响因子：
3.7
通讯作者：
Bogatkevich, Galina S.
中科院分区：
文献类型：
--
作者：
Atanelishvili, Ilia;Shirai, Yuichiro;Bogatkevich, Galina S.
肺纤维化代表了包括硬皮病相关间质性肺病在内的多种肺病的终末阶段。肺纤维化发病机制的分子机制还没有很好的理解，有一个更有效的治疗这种致命的疾病是一个巨大的需求。我们最近发现肝细胞生长因子（HGF）受体MET的一个小片段，命名为“M10”，具有很强的抗纤维化作用。此外，我们发现MET的1398位天冬氨酸对于M10的产生是必需的。本研究旨在研究MET的D1398 G变体，其中1398位的天冬氨酸突变为甘氨酸，导致M10缺失。我们证明，肺成纤维细胞，A549，和原代肺泡上皮细胞（AEC）表达D1398 G MET表现出减少的酪氨酸残基上的自磷酸化和减少的Ras和MAPK的激活。硬皮病肺成纤维细胞的HGF处理以及用野生型MET转染的TGF β处理的正常肺成纤维细胞的HGF处理与胶原蛋白、结缔组织生长因子（CTGF，CCN 2）和平滑肌α-肌动蛋白（SMA）减少相关。然而，HGF在用MET D1398 G转染的细胞中没有这种作用。顺铂和FasL诱导的细胞凋亡在MET野生型转染的AEC中显著减少，但在MET D1398 G转染的AEC中没有。我们得出结论，MET的D1398 G变体与肺成纤维细胞和AEC中受损的磷酸化和受损的HGF信号传导相关，这两种细胞类型与硬皮病相关的肺纤维化的发病机制有关。正在进行的研究将探讨这种变异的频率及其与硬皮病患者肺部结局的关系。
Pulmonary fibrosis represents the terminal stage of a diverse group of lung diseases including scleroderma associated interstitial lung disease. The molecular mechanisms underlying the pathogenesis of lung fibrosis are not well understood and there is a great need for more effective treatment for this lethal disease. We recently discovered a small fragment of hepatocyte growth factor (HGF) receptor MET as a peptide designated "M10," with strong antifi-brotic properties. Furthermore, we showed that aspartic acid at position 1398 of MET is essential for M10 generation. The current study was undertaken to investigate the D1398G variant of MET in which aspartic acid at position 1398 was mutated to glycine resulting in loss of M10. We demonstrate that lung fibroblasts, A549, and primary alveolar epithelial cells (AEC) expressing D1398G MET exhibit reduced auto-phosphorylation on tyrosine residues and reduced activation of Ras and MAPK. HGF treatment of scleroderma lung fibroblasts as well as HGF treatment of TGF beta-treated normal lung fibroblasts transfected with wild type MET is associated with decreased collagen, connective tissue growth factor (CTGF, CCN2) and smooth muscle alpha-actin (SMA). However, HGF has no such effects in cells transfected with MET D1398G. Cisplatin- and FasL-induced apoptosis is significantly reduced in AEC transfected with MET wild type, but not in AEC transfected with MET D1398G. We conclude that the D1398G variant of MET is associated with compromised phosphorylation and impaired HGF signaling in lung fibroblasts and AEC, two cell types implicated in the pathogenesis of pulmonary fibrosis associated with scleroderma. Ongoing studies will explore the frequency of this variant and its relationship to pulmonary outcomes in scleroderma patients.