Foxf1 enchances pulmonary inflammation and mastocytosis
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ABSTRACT: The Forkhead Box f1 (Foxf1) transcriptional factor (previously known as HFH-8 or Freac-1) is expressed in endothelial and smooth muscle cells in the embryonic and adult lung. To assess effects of Foxf1 during lung injury, we used CCl4 injury model. Foxf1+/- mice developed severe airway obstruction and bronchial edema, associated with increased numbers of pulmonary mast cells and increased mast cell degranulation following injury. Pulmonary inflammation in Foxf1+/- mice was associated with diminished expression of Foxf1, increased mast cell tryptase and increased expression of CXCL12, the latter being essential for mast cell migration and chemotaxis. Foxf1 haploinsufficiency caused pulmonary mastocytosis and enhanced pulmonary inflammation following chemically-induced lung injury, indicating an important role for Foxf1 in the pathogenesis of pulmonary inflammatory responses. Keywords: Influence of genetic modification on the pulmonary inflamation Foxf1+/- mice in which the Foxf1 allele was disrupted by an in-frame insertion of a nuclear localizing -galactosidase (-Gal) gene were bred for ten generations into the Black Swiss mouse genetic background. Carbon tetrachloride (CCl4; Sigma, St Louis, MO) was dissolved in mineral oil at a 1:20 ratio v/v and a single intraperitoneal (i.p.) injection of CCl4 (0.5 l of CCl4/ 1g of body weight) was administered to male Foxf1+/- mice or their wild type (WT) littermates as described.
Project description:The Forkhead Box f1 (Foxf1) transcriptional factor (previously known as HFH-8 or Freac-1) is expressed in endothelial and smooth muscle cells in the embryonic and adult lung. To assess effects of Foxf1 during lung injury, we used CCl4 injury model. Foxf1+/- mice developed severe airway obstruction and bronchial edema, associated with increased numbers of pulmonary mast cells and increased mast cell degranulation following injury. Pulmonary inflammation in Foxf1+/- mice was associated with diminished expression of Foxf1, increased mast cell tryptase and increased expression of CXCL12, the latter being essential for mast cell migration and chemotaxis. Foxf1 haploinsufficiency caused pulmonary mastocytosis and enhanced pulmonary inflammation following chemically-induced lung injury, indicating an important role for Foxf1 in the pathogenesis of pulmonary inflammatory responses. Keywords: Influence of genetic modification on the pulmonary inflamation
Project description:Multiple signaling pathways, structural proteins and transcription factors are involved in regulation of endothelial barrier function. The Forkhead protein FOXF1 is a key transcriptional regulator of lung embryonic development, and we use a conditional knockout approach to examine the role of FOXF1 in adult lung homeostasis and lung injury and repair. Tamoxifen-regulated deletion of both Foxf1 alleles in endothelial cells of adult mice (Pdgfb-iCreER/Foxf1 caused lung inflammation and edema, leading to respiratory insuffency and uniform mortality. Deletion of a single foxf1 allele was sufficient to increase susceptibility of heterozygous mice to acute lung injury. FOXF1 abundance was decreased in pulmonary endothelial cells of human patients with acute lung injury. Gene expression analysis of pulmonary endothelial cells of FOXF1 deletion indicated reduced expression for genes critical for maintance and regulation of adherens junctions. FOXF1 knockdown in vitro and in vivo disrupted adherens junctions, increased lung endothelial permeability, and the abundance of mRNA and protein for sphingosine 1 phosphate receptor 1 (S1PR1), a key regulator of endothelial barrier function. Chromatin immunoprecipitation and luciferase reporter assay demonstrated that FOXF1 directly bound to and induced the tanscriptional activity of the S1pr1 promoter. Pharmacological administratiion of S1P to injured pdgfb-iCreER/Foxf1 mice restored endothelial barrier function, decreased lung edema and improved survival. Thus, FOXF1 promotes normal lung homeostasis and lung repair, at least in part, by enhancing endothelial barrier function through transcriptional activation of the S1P/S1PR1/ signaling pathway.
Project description:FOXF1, a member of the forkhead box family of transcription factors, has been previously shown to be critical for lung development, homeostasis, and injury responses. However, the role of FOXF1 in lung regeneration is unknown. Herein, we performed partial pneumonectomy, a model of lung regeneration, in mice lacking one Foxf1 allele in endothelial cells (PDGFb-iCre/Foxf1fl/+ mice). Endothelial cell proliferation was significantly reduced in regenerating lungs from mice deficient for endothelial Foxf1. Decreased endothelial proliferation was associated with delayed lung regeneration as shown by reduced respiratory volume in Foxf1-deficient lungs. FACS-sorted endothelial cells isolated from regenerating PDGFb-iCre/Foxf1fl/+ and control lungs were used for RNAseq analysis to identify FOXF1 target genes. Foxf1 deficiency altered expression of numerous genes including those regulating extracellular matrix remodeling (Timp3, Adamts9) and cell cycle progression (Cdkn1a, Cdkn2b, Cenpj, Tubb4a), which are critical for lung regeneration. Deletion of Foxf1 increased Timp3 mRNA and protein, decreasing MMP14 activity in regenerating lungs. ChIPseq analysis for FOXF1 and histone methylation marks identified DNA regulatory regions with the Cd44, Cdkn1a, and Cdkn2b genes, indicating they are direct FOXF1 targets. Thus FOXF1 stimulates lung regeneration following partial pneumonectomy via direct transcriptional regulation of genes critical for extracellular matrix remodeling and cell cycle progression.
Project description:Pulmonary fibrosis results from dysregulated repair of damaged tissue caused by persistent injury of lung epithelium. Multiple cell types in the lung are involved in the process of repair. During lung fibrogenesis, normal endothelial cells (EC) are re-programmed into fibrosis-associated EC. Transcriptional factors that control re-programming are poorly understood. Using single cell RNA-sequencing of EC from donor and idiopathic pulmonary fibrosis (IPF) lungs, and lungs from bleomycin-treated mice, we identified endothelial transcription factors (TF) that were differentially expressed during fibrosis. Focusing on one of endothelial TF, FOXF1, we demonstrated that FOXF1 is decreased in EC within human IPF and mouse bleomycin-injured fibrotic lungs.
Project description:Pulmonary fibrosis results from dysregulated repair of damaged tissue caused by persistent injury of lung epithelium. Multiple cell types in the lung are involved in the process of repair. During lung fibrogenesis, normal endothelial cells (EC) are re-programmed into fibrosis-associated EC. Transcriptional factors that control re-programming are poorly understood. Using single cell RNA-sequencing of EC from donor and idiopathic pulmonary fibrosis (IPF) lungs, and lungs from bleomycin-treated mice, we identified endothelial transcription factors (TF) that were differentially expressed during fibrosis. Focusing on one of endothelial TF, FOXF1, we demonstrated that FOXF1 is decreased in EC within human IPF and mouse bleomycin-injured fibrotic lungs.
Project description:Pulmonary fibrosis results from dysregulated repair of damaged tissue caused by persistent injury of lung epithelium. Multiple cell types in the lung are involved in the process of repair. During lung fibrogenesis, normal endothelial cells (EC) are re-programmed into fibrosis-associated EC. Transcriptional factors that control re-programming are poorly understood. Using single cell RNA-sequencing of EC from donor and idiopathic pulmonary fibrosis (IPF) lungs, and lungs from bleomycin-treated mice, we identified endothelial transcription factors (TF) that were differentially expressed during fibrosis. Focusing on one of endothelial TF, FOXF1, we demonstrated that FOXF1 is decreased in EC within human IPF and mouse bleomycin-injured fibrotic lungs.
Project description:Pulmonary arterial hypertension (PAH) is a progressive disease in which pulmonary arterial (PA) endothelial cell (EC) dysfunction is associated with unrepaired DNA damage. BMPR2 is the most common mutant gene in PAH. We report that human PAEC with reduced BMPR2 have persistent DNA damage in room air after hypoxic exposure (reoxygenation), as do mice with EC deletion of Bmpr2 (EC-Bmpr2-/-) and persistent pulmonary hypertension. Similar findings are observed in PAEC with loss of the DNA damage sensor ATM, and in mice with Atm deleted in EC (EC-Atm-/-). Gene expression analysis of EC-Atm-/- and EC-Bmpr2-/- lung EC revealed reduced Foxf1, a transcription factor with relative selectivity for lung EC. Reducing FOXF1 in control PAEC induced DNA damage and impaired angiogenesis whereas transfection of FOXF1 in PAH PAEC repaired DNA damage and restored angiogenesis. Lung EC targeted delivery of Foxf1 to reoxygenated EC-Bmpr2-/- mice repaired DNA damage, induced angiogenesis and reversed pulmonary hypertension.
Project description:Idiopathic pulmonary fibrosis (IPF) is characterized by aberrant accumulation of collagen-secreting myofibroblasts. Development of effective therapies is limited due to incomplete understanding of molecular mechanisms regulating myofibroblast expansion. FOXF1 transcription factor is expressed in resident lung fibroblasts, but its role in lung fibrosis remains unknown due to the lack of genetic mouse models. Through comprehensive analysis of human IPF genomics data, lung biopsies and transgenic mice with fibroblast-specific inactivation of FOXF1, the present study shows that FOXF1 inhibits pulmonary fibrosis. FOXF1 deletion increases myofibroblast invasion, collagen secretion, and promotes a switch from of N-cadherin (CDH2) to Cadherin-11 (CDH11), which is critical step in acquisition of pro-fibrotic phenotype. FOXF1 directly binds to Cdh2 and Cdh11 promoters and differentially regulates transcription of these genes. Re-expression of CDH2 or inhibition of CDH11 in FOXF1-deficient cells reduces myofibroblast invasion in vitro. FOXF1 inhibits pulmonary fibrosis by regulating a switch from CDH2 to CDH11 in lung myofibroblasts.
Project description:Aberrant expression of master phenotype regulators by 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 compared with controls. In normal lung fibroblasts, FOXF1 repressed key fibroblast functions such as proliferation, survival, and expression of collagen-1 (COL1) and actin related protein 2/3 complex, subunit 2 (ARPC2). ARPC2 knockdown mimicked FOXF1 overexpression with regard to proliferation and COL1 expression. FOXF1 expression was induced by the antifibrotic mediator prostaglandin E2 (PGE2). Ex vivo, FOXF1 knockdown conferred CCL-210 lung fibroblasts the ability to implant and survive in uninjured mouse lungs. In IPF lung fibroblasts, FOXF1 regulated COL1 but not ARPC2 expression. In conclusion, FOXF1 functions and regulation were consistent with an antifibrotic role in lung fibroblasts. Higher FOXF1 levels in IPF fibroblasts may thus participate in a compensatory response to fibrogenesis. Lung fibroblasts derived from 4 different IPF patients (P313, P355, P375 and P426) were transiently transfected with pcfoxf1 or control pcDNA3.1-constructs. Total RNAs were extracted 24 h after transfection and hybridized on microarrays. One color experiment with 2 experimental conditions: pcfoxf1 and pcDNA3.1
Project description:Aberrant expression of master phenotype regulators by 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 compared with controls. In normal lung fibroblasts, FOXF1 repressed key fibroblast functions such as proliferation, survival, and expression of collagen-1 (COL1) and actin related protein 2/3 complex, subunit 2 (ARPC2). ARPC2 knockdown mimicked FOXF1 overexpression with regard to proliferation and COL1 expression. FOXF1 expression was induced by the antifibrotic mediator prostaglandin E2 (PGE2). Ex vivo, FOXF1 knockdown conferred CCL-210 lung fibroblasts the ability to implant and survive in uninjured mouse lungs. In IPF lung fibroblasts, FOXF1 regulated COL1 but not ARPC2 expression. In conclusion, FOXF1 functions and regulation were consistent with an antifibrotic role in lung fibroblasts. Higher FOXF1 levels in IPF fibroblasts may thus participate in a compensatory response to fibrogenesis.