Gene profile of fibroblasts identify relation of CCL8 with idiopathic pulmonary fibrosis

Abstract

BackgroundIdiopathic pulmonary fibrosis (IPF) is characterized by the complex interaction of cells involved in chronic inflammation and fibrosis. Global gene expression of a homogenous cell population will identify novel candidate genes.MethodsGene expression of fibroblasts derived from lung tissues (8 IPF and 4 controls) was profiled, and ontology and functional pathway were analyzed in the genes exhibiting >2 absolute fold changes with p-values < 0.05. CCL8 mRNA and protein levels were quantified using real-time PCR and ELISA. CCL8 localization was evaluated by immunofluorescence staining.ResultsOne hundred seventy eight genes differentially expressed and 15 genes exhibited >10-fold change. Among them, 13 were novel in relation with IPF. CCL8 expression was 22.8-fold higher in IPF fibroblasts. The levels of CCL8 mRNA and protein were 3 and 9-fold higher in 14 IPF fibroblasts than those in 10 control fibroblasts by real-time PCR and ELISA (p = 0.022 and p = 0.026, respectively). The CCL8 concentrations in BAL fluid was significantly higher in 86 patients with IPF than those in 41 controls, and other interstitial lung diseases including non-specific interstitial pneumonia (n = 22), hypersensitivity pneumonitis (n = 20) and sarcoidosis (n = 19) (p < 0.005, respectively). Cut-off values of 2.29 pg/mL and 0.43 pg/mL possessed 80.2 and 70.7% accuracy for the discrimination of IPF from NC and the other lung diseases, respectively. IPF subjects with CCL8 levels >28.61 pg/mL showed shorter survival compared to those with lower levels (p = 0.012). CCL8 was expressed by α-SMA-positive cells in the interstitium of IPF.ConclusionsTranscriptome analysis identified several novel IPF-related genes. Among them, CCL8 is a candidate molecule for the differential diagnosis and prediction of survival.Electronic supplementary materialThe online version of this article (doi:10.1186/s12931-016-0493-6) contains supplementary material, which is available to authorized users.

Periostin plays a critical role in the cell cycle in lung fibroblasts

“…These differences include several signature molecules of IPF such as IGFBP-3 and lysyl oxidase [3]. Lee et al have reported that periostin expression is enhanced in fibroblasts derived from IPF patients, although expression levels of periostin vary among the clones [5]. We observed that some clones of IPF lung fibroblasts show high expression of periostin compared to normal lung fibroblasts, whereas there was no statistical significance because of the heterogeneity of IPF lung fibroblasts (Fig.…”

“…IPF fibroblasts display enhanced proliferation on polymerized collagen matrices [41]. Moreover, profiles of expressed genes differ between IPF patients and normal donors [3][4][5] . These differences include several signature molecules of IPF such as IGFBP-3 and lysyl oxidase [3].…”

“…It is still uncertain whether, in the lung tissues of IPF patients, the progressive proliferation of fibroblasts is programmed in fibroblasts themselves or is in some way influenced by the extracellular milieu. Several trials have been performed to compare gene profiles in fibroblasts derived from IPF patients and normal donors [3][4][5], showing that gene expression patterns differ in these two types of fibroblasts. Expression of fibrosis-related genes (IGFBP3, IGFBP7, LOX, and POSTN) chemokines (CCL2, CCL8, and CCL26), and growth factors such as FGF7 are upregulated in IPF fibroblasts.…”

Upregulation of Potassium Voltage-Gated Channel Subfamily J Member 2 Levels in the Lungs of Patients with Idiopathic Pulmonary Fibrosis

“…Fibroblast cultures were obtained from 14 IPF patients and 10 NCs who underwent lung surgery, and the clinical information and laboratory data of these subjects were summarized in our previous study [10]. BAL fluid samples were obtained from patients with IPF (n � 84), NSIP (n � 9), hypersensitivity pneumonitis (n � 8), and sarcoidosis (n � 10), and the clinical characteristics of these patients are summarized in Table 1.…”

“…Recently, global gene expression levels in lung tissues were compared to identify genes involved in the complex mechanism of IPF [6][7][8][9]. We also identified 178 of the total of 15,020 genes that were differentially expressed in lung fibroblasts from IPF patients and controls [10]. Among these genes, the mRNA expression of potassium voltage-gated channel subfamily J member 2 (KCNJ2) was 18.6-fold higher in IPF than control subjects.…”