scholarly journals Compromised peroxisomes in idiopathic pulmonary fibrosis, a vicious cycle inducing a higher fibrotic response via TGF-β signaling

2015 ◽  
Vol 112 (16) ◽  
pp. E2048-E2057 ◽  
Author(s):  
Gani Oruqaj ◽  
Srikanth Karnati ◽  
Vijith Vijayan ◽  
Lakshmi Kanth Kotarkonda ◽  
Eistine Boateng ◽  
...  

Idiopathic pulmonary fibrosis (IPF) is a devastating disease, and its pathogenic mechanisms remain incompletely understood. Peroxisomes are known to be important in ROS and proinflammatory lipid degradation, and their deficiency induces liver fibrosis. However, altered peroxisome functions in IPF pathogenesis have never been investigated. By comparing peroxisome-related protein and gene expression in lung tissue and isolated lung fibroblasts between human control and IPF patients, we found that IPF lungs exhibited a significant down-regulation of peroxisomal biogenesis and metabolism (e.g., PEX13p and acyl-CoA oxidase 1). Moreover, in vivo the bleomycin-induced down-regulation of peroxisomes was abrogated in transforming growth factor beta (TGF-β) receptor II knockout mice indicating a role for TGF-β signaling in the regulation of peroxisomes. Furthermore, in vitro treatment of IPF fibroblasts with the profibrotic factors TGF-β1 or tumor necrosis factor alpha (TNF-α) was found to down-regulate peroxisomes via the AP-1 signaling pathway. Therefore, the molecular mechanisms by which reduced peroxisomal functions contribute to enhanced fibrosis were further studied. Direct down-regulation of PEX13 by RNAi induced the activation of Smad-dependent TGF-β signaling accompanied by increased ROS production and resulted in the release of cytokines (e.g., IL-6, TGF-β) and excessive production of collagen I and III. In contrast, treatment of fibroblasts with ciprofibrate or WY14643, PPAR-α activators, led to peroxisome proliferation and reduced the TGF-β–induced myofibroblast differentiation and collagen protein in IPF cells. Taken together, our findings suggest that compromised peroxisome activity might play an important role in the molecular pathogenesis of IPF and fibrosis progression, possibly by exacerbating pulmonary inflammation and intensifying the fibrotic response in the patients.

2018 ◽  
Vol 29 (18) ◽  
pp. 2165-2175 ◽  
Author(s):  
Elizabeth Monaghan-Benson ◽  
Erika S. Wittchen ◽  
Claire M. Doerschuk ◽  
Keith Burridge

Idiopathic pulmonary fibrosis (IPF) is an incurable disease of the lung that is characterized by excessive deposition of extracellular matrix (ECM), resulting in disruption of normal lung function. The signals regulating fibrosis include both transforming growth factor beta (TGF-β) and tissue rigidity and a major signaling pathway implicated in fibrosis involves activation of the GTPase RhoA. During studies exploring how elevated RhoA activity is sustained in IPF, we discovered that not only is RhoA activated by profibrotic stimuli but also that the expression of Rnd3, a major antagonist of RhoA activity, and the activity of p190RhoGAP (p190), a Rnd3 effector, are both suppressed in IPF fibroblasts. Restoration of Rnd3 levels in IPF fibroblasts results in an increase in p190 activity, a decrease in RhoA activity and a decrease in the overall fibrotic phenotype. We also find that treatment with IPF drugs nintedanib and pirfenidone decreases the fibrotic phenotype and RhoA activity through up-regulation of Rnd3 expression and p190 activity. These data provide evidence for a pathway in IPF where fibroblasts down-regulate Rnd3 levels and p190 activity to enhance RhoA activity and drive the fibrotic phenotype.


Antioxidants ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1833
Author(s):  
Sanja Blaskovic ◽  
Yves Donati ◽  
Isabelle Ruchonnet-Metrailler ◽  
Tamara Seredenina ◽  
Karl-Heinz Krause ◽  
...  

Idiopathic pulmonary fibrosis (IPF) is a noninflammatory progressive lung disease. Oxidative damage is a hallmark of IPF, but the sources and consequences of oxidant generation in the lungs are unclear. In this study, we addressed the link between the H2O2-generating enzyme NADPH oxidase 4 (NOX4) and di-tyrosine (DT), an oxidative post-translational modification in IPF lungs. We performed immunohistochemical staining for DT and NOX4 in pulmonary tissue from patients with IPF and controls using validated antibodies. In the healthy lung, DT showed little or no staining and NOX4 was mostly present in normal vascular endothelium. On the other hand, both markers were detected in several cell types in the IPF patients, including vascular smooth muscle cells and epithelium (bronchial cells and epithelial cells type II). The link between NOX4 and DT was addressed in human fibroblasts deficient for NOX4 activity (mutation in the CYBA gene). Induction of NOX4 by Transforming growth factor beta 1 (TGFβ1) in fibroblasts led to moderate DT staining after the addition of a heme-containing peroxidase in control cells but not in the fibroblasts deficient for NOX4 activity. Our data indicate that DT is a histological marker of IPF and that NOX4 can generate a sufficient amount of H2O2 for DT formation in vitro.


2018 ◽  
Vol 132 (14) ◽  
pp. 1565-1580 ◽  
Author(s):  
Yasunori Enomoto ◽  
Sayomi Matsushima ◽  
Kiyoshi Shibata ◽  
Yoichiro Aoshima ◽  
Haruna Yagi ◽  
...  

Although differentiation of lung fibroblasts into α-smooth muscle actin (αSMA)-positive myofibroblasts is important in the progression of idiopathic pulmonary fibrosis (IPF), few biomarkers reflecting the fibrotic process have been discovered. We performed microarray analyses between FACS-sorted steady-state fibroblasts (lineage (CD45, TER-119, CD324, CD31, LYVE-1, and CD146)-negative and PDGFRα-positive cells) from untreated mouse lungs and myofibroblasts (lineage-negative, Sca-1-negative, and CD49e-positive cells) from bleomycin-treated mouse lungs. Amongst several genes up-regulated in the FACS-sorted myofibroblasts, we focussed on Ltbp2, the gene encoding latent transforming growth factor-β (TGF-β) binding protein-2 (LTBP2), because of the signal similarity to Acta2, which encodes αSMA, in the clustering analysis. The up-regulation was reproduced at the mRNA and protein levels in human lung myofibroblasts induced by TGF-β1. LTBP2 staining in IPF lungs was broadly positive in the fibrotic interstitium, mainly as an extracellular matrix (ECM) protein; however, some of the αSMA-positive myofibroblasts were also stained. Serum LTBP2 concentrations, evaluated using ELISA, in IPF patients were significantly higher than those in healthy volunteers (mean: 21.4 compared with 12.4 ng/ml) and showed a negative correlation with % predicted forced vital capacity (r = −0.369). The Cox hazard model demonstrated that serum LTBP2 could predict the prognosis of IPF patients (hazard ratio for death by respiratory events: 1.040, 95% confidence interval: 1.026–1.054), which was validated using the bootstrap method with 1000-fold replication. LTBP2 is a potential prognostic blood biomarker that may reflect the level of differentiation of lung fibroblasts into myofibroblasts in IPF.


2015 ◽  
Vol 45 (5) ◽  
pp. 1434-1445 ◽  
Author(s):  
Lutz Wollin ◽  
Eva Wex ◽  
Alexander Pautsch ◽  
Gisela Schnapp ◽  
Katrin E. Hostettler ◽  
...  

Idiopathic pulmonary fibrosis (IPF) is a progressive and ultimately fatal disease characterised by fibrosis of the lung parenchyma and loss of lung function. Although the pathogenic pathways involved in IPF have not been fully elucidated, IPF is believed to be caused by repetitive alveolar epithelial cell injury and dysregulated repair, in which there is uncontrolled proliferation of lung fibroblasts and differentiation of fibroblasts into myofibroblasts, which excessively deposit extracellular matrix (ECM) proteins in the interstitial space. A number of profibrotic mediators including platelet-derived growth factor (PDGF), fibroblast growth factor (FGF) and transforming growth factor-β are believed to play important roles in the pathogenesis of IPF. Nintedanib is a potent small molecule inhibitor of the receptor tyrosine kinases PDGF receptor, FGF receptor and vascular endothelial growth factor receptor. Data from in vitro studies have shown that nintedanib interferes with processes active in fibrosis such as fibroblast proliferation, migration and differentiation, and the secretion of ECM. In addition, nintedanib has shown consistent anti-fibrotic and anti-inflammatory activity in animal models of lung fibrosis. These data provide a strong rationale for the clinical efficacy of nintedanib in patients with IPF, which has recently been demonstrated in phase III clinical trials.


2021 ◽  
Vol 12 ◽  
Author(s):  
Weimou Chen ◽  
Jinming Zhang ◽  
Wenshan Zhong ◽  
Yuanyuan Liu ◽  
Ye Lu ◽  
...  

Idiopathic pulmonary fibrosis (IPF) is a fatal disease in which the normal alveolar network is gradually replaced by fibrotic scars. Current evidence suggests that metabolic alterations correlate with myofibroblast activation in IPF. Anlotinib has been proposed to have antifibrotic effects, but the efficacy and mechanisms of anlotinib against lung fibrosis have not been systematically evaluated. The antifibrotic effects of anlotinib were evaluated in bleomycin-induced mouse models and transforming growth factor-beta 1 (TGF-β1)-stimulated lung fibroblasts. We measured lactate levels, 2-NBDG glucose uptake and the extracellular acidification rate (ECAR) to assess glycolysis in fibroblasts. RNA-protein coimmunoprecipitation (RIP) and polysome analyses were performed to investigate novel mechanisms of glycolytic reprogramming in pulmonary fibrosis. We found that anlotinib diminished myofibroblast activation and inhibited the augmentation of glycolysis. Moreover, we show that PCBP3 posttranscriptionally increases PFKFB3 expression by promoting its translation during myofibroblast activation, thus promoting glycolysis in myofibroblasts. Regarding mechanism, anlotinib exerts potent antifibrotic effects by downregulating PCBP3, reducing PFKFB3 translation and inhibiting glycolysis in myofibroblasts. Furthermore, we observed that anlotinib had preventative and therapeutic antifibrotic effects on bleomycin-induced pulmonary fibrosis. Therefore, we identify PCBP3 as a protein involved in the regulation of glycolysis reprogramming and lung fibrogenesis and propose it as a therapeutic target for pulmonary fibrosis. Our data suggest that anlotinib has antifibrotic effects on the lungs, and we provide a novel mechanism for this effect. Anlotinib may constitute a novel and potent candidate for the treatment of pulmonary fibrosis.


2022 ◽  
Author(s):  
Farida Ahangari ◽  
Christine Becker ◽  
Daniel G Foster ◽  
Maurizio Chioccioli ◽  
Meghan Nelson ◽  
...  

Idiopathic Pulmonary Fibrosis (IPF) is a chronic, progressive, and often fatal disorder. Two FDA approved anti-fibrotic drugs, nintedanib and pirfenidone, slow the rate of decline in lung function, but responses are variable and side effects are common. Using an in-silico data-driven approach, we identified a robust connection between the transcriptomic perturbations in IPF disease and those induced by saracatinib, a selective Src kinase inhibitor, originally developed for oncological indications. Based on these observations, we hypothesized that saracatinib would be effective at attenuating pulmonary fibrosis. We investigated the anti-fibrotic efficacy of saracatinib relative to nintedanib and pirfenidone in three preclinical models: (i) in vitro in normal human lung fibroblasts (NHLFs); (ii) in vivo in bleomycin and recombinant adenovirus transforming growth factor-beta (Ad-TGF-β) murine models of pulmonary fibrosis; and (iii) ex vivo in precision cut lung slices from these mouse models. In each model, the effectiveness of saracatinib in blocking fibrogenic responses was equal or superior to nintedanib and pirfenidone.


2021 ◽  
Author(s):  
Lili Su ◽  
Yonggang Wang ◽  
Daowei Li ◽  
Xingguang Wang ◽  
Bin Liang ◽  
...  

Abstract Malignant pleural mesothelioma (MPM) is a highly aggressive and lethal malignancy; however, its molecular origins remain largely unknown. The purpose of this study was to use transcriptomics to explore the molecular mechanisms of MPM tumorigenesis toward gaining a better understanding of disease development. The transcriptomes from MPM tissues and paired normal pleural tissues were compared to identify significantly differentially expressed genes. These genes were then subject to Gene Ontology analysis to explore pathways that are dysregulated in MPM, and The Cancer Genome Atlas (TCGA) gene expression profile data were analyzed to assess the correlation between the significantly dysregulated pathways and patient survival. Moreover, three independent transcriptomic datasets were used to validate the association between significantly dysregulated genes and the clinical features of MPM. We identified 136 up-regulated and 599 down-regulated genes in MPM tissues as compared to normal pleural tissues. Functional enrichment analysis showed that the up-regulated genes were mainly associated with mitotic nuclear division, whereas the down-regulated genes were mainly associated with transforming growth factor beta (TGF-β) signaling. The 14 most significantly up-regulated mitotic nuclear division-related genes were more likely to be highly expressed in pathological subtypes with higher malignancy, whereas the down-regulated TGF-β pathway-related gene PPARGC1A displayed the opposite trend. In the TCGA dataset, up-regulation of mitotic nuclear division-related genes was associated with a poor prognosis, whereas down-regulation of TGF-β pathway-related genes was associated with a positive prognosis. The down-regulated PPARGC1A were further validated by immunohistochemical analysis. In summary, the correlation between up-regulation of mitotic nuclear division-related genes and down-regulation of the TGF-β pathway-related gene PPARGC1A with overall survival indicates an important role for these genes in MPM development and progression.


2016 ◽  
Vol 310 (10) ◽  
pp. L940-L954 ◽  
Author(s):  
Irina G. Luzina ◽  
Virginia Lockatell ◽  
Sang W. Hyun ◽  
Pavel Kopach ◽  
Phillip H. Kang ◽  
...  

Idiopathic pulmonary fibrosis (IPF) poses challenges to understanding its underlying cellular and molecular mechanisms and the development of better therapies. Previous studies suggest a pathophysiological role for neuraminidase 1 (NEU1), an enzyme that removes terminal sialic acid from glycoproteins. We observed increased NEU1 expression in epithelial and endothelial cells, as well as fibroblasts, in the lungs of patients with IPF compared with healthy control lungs. Recombinant adenovirus-mediated gene delivery of NEU1 to cultured primary human cells elicited profound changes in cellular phenotypes. Small airway epithelial cell migration was impaired in wounding assays, whereas, in pulmonary microvascular endothelial cells, NEU1 overexpression strongly impacted global gene expression, increased T cell adhesion to endothelial monolayers, and disrupted endothelial capillary-like tube formation. NEU1 overexpression in fibroblasts provoked increased levels of collagen types I and III, substantial changes in global gene expression, and accelerated degradation of matrix metalloproteinase-14. Intratracheal instillation of NEU1 encoding, but not control adenovirus, induced lymphocyte accumulation in bronchoalveolar lavage samples and lung tissues and elevations of pulmonary transforming growth factor-β and collagen. The lymphocytes were predominantly T cells, with CD8+ cells exceeding CD4+ cells by nearly twofold. These combined data indicate that elevated NEU1 expression alters functional activities of distinct lung cell types in vitro and recapitulates lymphocytic infiltration and collagen accumulation in vivo, consistent with mechanisms implicated in lung fibrosis.


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