Forkhead Box F1 represses cell growth and inhibits COL1 and ARPC2 expression in lung fibroblasts in vitro

Abstract

Aberrant expression of master phenotype regulators or alterations in their downstream pathways in lung fibroblasts may play a central role in idiopathic pulmonary fibrosis (IPF). Interrogating IPF fibroblast transcriptome datasets, we identified Forkhead Box F1 (FOXF1), a DNA-binding protein required for lung development, as a candidate actor in IPF. Thus we determined FOXF1 expression levels in fibroblasts cultured from normal or IPF lungs in vitro, and explored FOXF1 functions in these cells using transient and stable loss-of-function and gain-of-function models. FOXF1 mRNA and protein were expressed at higher levels in IPF fibroblasts compared with normal fibroblasts (mRNA: ϩ44%, protein: ϩ77%). Immunohistochemistry showed FOXF1 expression in nuclei of bronchial smooth muscle cells, endothelial cells, and lung fibroblasts including fibroblastic foci of IPF lungs. In normal lung fibroblasts, FOXF1 repressed cell growth and expression of collagen-1 (COL1) and actin-related protein 2/3 complex, subunit 2 (ARPC2). ARPC2 knockdown inhibited cell growth and COL1 expression, consistent with FOXF1 acting in part through ARPC2 repression. In IPF fibroblasts, COL1 and ARPC2 repression by FOXF1 was blunted, and FOXF1 did not repress growth. FOXF1 expression was induced by the antifibrotic mediator prostaglandin E 2 and repressed by the profibrotic cytokine transforming growth factor-␤1 in both normal and IPF lung fibroblasts. Ex vivo, FOXF1 knockdown conferred CCL-210 lung fibroblasts the ability to implant in uninjured mouse lungs. In conclusion, FOXF1 functions and regulation were consistent with participation in antifibrotic pathways. Alterations of pathways downstream of FOXF1 may participate to fibrogenesis in IPF fibroblasts.

Membrane-anchored Serine Protease Matriptase Is a Trigger of Pulmonary Fibrogenesis

“…control lungs was verified histologically as described previously (15,16 Experiments with matriptase hypomorphic mice were littermate controlled from mice generated from heterozygous crosses (18). The bleomycin murine model of pulmonary fibrosis was set up as described previously (19).…”

Role of ARPC2 in Human Gastric Cancer

“…Ghouleh et al demonstrated that ARPC2 participated in promoting smooth muscle cell migration [6]. Melboucy-Belkhir et al determined that ARPC2 was regulated by Forkhead box F1 (FOXF1) and might be involved in cell growth of lung fibroblasts [12]. To date, there is no publication that documents the relation between ARPC2 and tumor proliferation or invasion.…”

Transcriptome of Cultured Lung Fibroblasts in Idiopathic Pulmonary Fibrosis: Meta-Analysis of Publically Available Microarray Datasets Reveals Repression of Inflammation and Immunity Pathways

“…To this aim, multiple experiments comparing the transcriptome of IPF lung fibroblasts to normal lung fibroblasts using RNA microarrays were previously published [5,6,7,8]. These studies yielded conflicting results with little overlap [9], most likely because of the generally small study size, of the high variability inherent to clinical samples, and of possible center-related bias. We hypothesized that combining these individual studies into a single meta-analysis may allow for the identification of robust alterations of mRNA expression in IPF fibroblasts, with the potential to reveal or confirm pathogenic mechanisms and therapeutic targets.…”