Interstitial Lung Disease Unit, Royal Brompton Hospital and National Heart and Lung Institute, Imperial College London, Emmanuel Kaye Building, 1B Manresa Road, London SW3 6LR, UK.
Respir Res. 2013 Aug 2;14(1):80. doi: 10.1186/1465-9921-14-80.
Interstitial lung disease is a major cause of morbidity and mortality in systemic sclerosis (SSc), with insufficiently effective treatment options. Progression of pulmonary fibrosis involves expanding populations of fibroblasts, and the accumulation of extracellular matrix proteins. Characterisation of SSc lung fibroblast gene expression profiles underlying the fibrotic cell phenotype could enable a better understanding of the processes leading to the progressive build-up of scar tissue in the lungs. In this study we evaluate the transcriptomes of fibroblasts isolated from SSc lung biopsies at the time of diagnosis, compared with those from control lungs.
We used Affymetrix oligonucleotide microarrays to compare the gene expression profile of pulmonary fibroblasts cultured from 8 patients with pulmonary fibrosis associated with SSc (SSc-ILD), with those from control lung tissue peripheral to resected cancer (n=10). Fibroblast cultures from 3 patients with idiopathic pulmonary fibrosis (IPF) were included as a further comparison. Genes differentially expressed were identified using two separate analysis programs following a set of pre-determined criteria: only genes significant in both analyses were considered. Microarray expression data was verified by qRT-PCR and/or western blot analysis.
A total of 843 genes were identified as differentially expressed in pulmonary fibroblasts from SSc-ILD and/or IPF compared to control lung, with a large overlap in the expression profiles of both diseases. We observed increased expression of a TGF-β response signature including fibrosis associated genes and myofibroblast markers, with marked heterogeneity across samples. Strongly suppressed expression of interferon stimulated genes, including antiviral, chemokine, and MHC class 1 genes, was uniformly observed in fibrotic fibroblasts. This expression profile includes key regulators and mediators of the interferon response, such as STAT1, and CXCL10, and was also independent of disease group.
This study identified a strongly suppressed interferon-stimulated gene program in fibroblasts from fibrotic lung. The data suggests that the repressed expression of interferon-stimulated genes may underpin critical aspects of the profibrotic fibroblast phenotype, identifying an area in pulmonary fibrosis that requires further investigation.
间质性肺病是系统性硬化症（SSc）患者发病率和死亡率的主要原因，目前治疗方法效果不佳。肺纤维化的进展涉及到成纤维细胞数量的增加，以及细胞外基质蛋白的积累。对 SSc 肺成纤维细胞纤维化细胞表型相关的基因表达谱进行特征分析，可以更好地理解导致肺部疤痕组织进行性堆积的过程。在这项研究中，我们比较了诊断时 SSc 肺活检中分离的成纤维细胞与对照肺组织的转录组。
我们使用 Affymetrix 寡核苷酸微阵列比较了 8 例 SSc-ILD 相关肺纤维化患者培养的肺成纤维细胞和 10 例切除癌症的肺组织周围对照肺成纤维细胞的基因表达谱。还纳入了 3 例特发性肺纤维化（IPF）患者的成纤维细胞作为进一步比较。使用两个独立的分析程序，并遵循一系列预定标准来识别差异表达的基因：只有在两个分析中均显著的基因才被认为是差异表达基因。通过 qRT-PCR 和/或 Western blot 分析验证微阵列表达数据。
与对照肺组织相比，SSc-ILD 和/或 IPF 患者的肺成纤维细胞中共有 843 个基因差异表达，两种疾病的表达谱有很大的重叠。我们观察到 TGF-β 反应特征的表达增加，包括纤维化相关基因和肌成纤维细胞标记物，并且在样本中存在明显的异质性。干扰素刺激基因的表达受到强烈抑制，包括抗病毒、趋化因子和 MHC Ⅰ类基因，在纤维化成纤维细胞中普遍观察到。这种表达谱包括干扰素反应的关键调节剂和介质，如 STAT1 和 CXCL10，并且与疾病组无关。
这项研究鉴定了纤维化肺成纤维细胞中强烈抑制的干扰素刺激基因程序。数据表明，干扰素刺激基因的抑制表达可能是成纤维细胞的促纤维化表型的关键方面，确定了肺纤维化需要进一步研究的一个领域。
