scholarly journals Proliferating SPP1/MERTK-expressing macrophages in idiopathic pulmonary fibrosis

2019 ◽  
Vol 54 (2) ◽  
pp. 1802441 ◽  
Author(s):  
Christina Morse ◽  
Tracy Tabib ◽  
John Sembrat ◽  
Kristina L. Buschur ◽  
Humberto Trejo Bittar ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Idiopathic Pulmonary Fibrosis ◽  
Pulmonary Fibrosis ◽  
Lung Fibrosis ◽  
Inflammatory Cells ◽  
Cell Types ◽  
Alveolar Epithelial Cells ◽  
Alveolar Epithelial ◽  
Macrophage Subpopulations ◽  
Normal Lungs

A comprehensive understanding of the changes in gene expression in cell types involved in idiopathic pulmonary fibrosis (IPF) will shed light on the mechanisms underlying the loss of alveolar epithelial cells and development of honeycomb cysts and fibroblastic foci. We sought to understand changes in IPF lung cell transcriptomes and gain insight into innate immune aspects of pathogenesis.We investigated IPF pathogenesis using single-cell RNA-sequencing of fresh lung explants, comparing human IPF fibrotic lower lobes reflecting late disease, upper lobes reflecting early disease and normal lungs.IPF lower lobes showed increased fibroblasts, and basal, ciliated, goblet and club cells, but decreased alveolar epithelial cells, and marked alterations in inflammatory cells. We found three discrete macrophage subpopulations in normal and fibrotic lungs, one expressing monocyte markers, one highly expressing FABP4 and INHBA (FABP4hi), and one highly expressing SPP1 and MERTK (SPP1hi). SPP1hi macrophages in fibrotic lower lobes showed highly upregulated SPP1 and MERTK expression. Low-level local proliferation of SPP1hi macrophages in normal lungs was strikingly increased in IPF lungs.Co-localisation and causal modelling supported the role for these highly proliferative SPP1hi macrophages in activation of IPF myofibroblasts in lung fibrosis. These data suggest that SPP1hi macrophages contribute importantly to lung fibrosis in IPF, and that therapeutic strategies targeting MERTK and macrophage proliferation may show promise for treatment of this disease.

scholarly journals Effects of the Cytoplasm and Mitochondrial Specific Hydroxyl Radical Scavengers TA293 and mitoTA293 in Bleomycin-Induced Pulmonary Fibrosis Model Mice

Antioxidants ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1398
Author(s):  
Takahiro Sakai ◽  
Hidetsugu Takagaki ◽  
Noriyuki Yamagiwa ◽  
Michio Ui ◽  
Shinichi Hatta ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Idiopathic Pulmonary Fibrosis ◽  
Pulmonary Fibrosis ◽  
Hydroxyl Radical ◽  
P38 Mapk ◽  
Cellular Senescence ◽  
Nlrp3 Inflammasome ◽  
Lung Fibrosis ◽  
Alveolar Epithelial Cells ◽  
Alveolar Epithelial

Lung fibrosis is the primary pathology in idiopathic pulmonary fibrosis and is considered to result from an increase in reactive oxygen species (ROS) levels in alveolar epithelial cells. However, the exact mechanism underlying lung fibrosis remains unclear and there is no effective therapy. The hydroxyl radical (•OH) has the strongest oxidizing potential among ROS. Recently, •OH localized to the cytoplasm (cyto •OH) was reported to induce cellular senescence, while mitochondria-localized •OH (mt •OH) was reported to induce apoptosis. We developed the cyto •OH- and mt •OH-scavenging antioxidants TA293 and mitoTA293 to evaluate the effects of cyto •OH and mt •OH in a bleomycin (BLM)-induced pulmonary fibrosis model. Treatment of BLM-induced pulmonary fibrosis mice with TA293 suppressed the induction of cellular senescence and fibrosis, as well as inflammation in the lung, but mitoTA293 exacerbated these. Furthermore, in BLM-stimulated primary alveolar epithelial cells, TA293 suppressed the activation of the p-ATMser1981/p-p53ser15/p21, p-HRI/p-eIF2ser51/ATF4/p16, NLRP3 inflammasome/caspase-1/IL-1β/IL1R/p-p38 MAPK/p16, and p21 pathways and the induction of cellular senescence. However, mitoTA293 suppressed the induction of mitophagy, enhanced the activation of the NLRP3 inflammasome/caspase-1/IL1β/IL1R/p-p38 MAPK/p16 and p21 pathways, and exacerbated cellular senescence, inflammation, and fibrosis. Our findings may help develop new strategies to treat idiopathic pulmonary fibrosis.

scholarly journals IL-25 contributes to lung fibrosis by directly acting on alveolar epithelial cells and fibroblasts

2019 ◽  
Vol 244 (9) ◽  
pp. 770-780 ◽  
Author(s):  
Xuefeng Xu ◽  
Sa Luo ◽  
Biyun Li ◽  
Huaping Dai ◽  
Jinglan Zhang
Keyword(s):  
Epithelial Cells ◽  
Idiopathic Pulmonary Fibrosis ◽  
Pulmonary Fibrosis ◽  
Lung Fibrosis ◽  
Lung Fibroblast ◽  
Alveolar Epithelial Cells ◽  
Lung Fibroblasts ◽  
Rt Pcr ◽  
Alveolar Epithelial

Interleukin (IL)-25 is shown to potentiate type-2 immunity and contribute to chronic airway inflammation and remodeling in allergic airway diseases. However, the role of IL-25 in idiopathic pulmonary fibrosis (IPF), dominated by nonatopic type-2 immunity, still remains largely unclear. Herein, we detected the expression levels of IL-25 and IL-17BR (IL-25’s receptor) by using lung tissue samples gained from IPF patients and normal subjects. Also, by directly intranasal (IN) instillation of IL-25 to mice, we examined the potential roles and mechanisms of IL-25 in the development of lung fibrosis. Furthermore, we tested whether IL-25 can directly activate human lung fibroblast by in vitro cell culture. Immunohistochemical, Western blot, and real-time reverse transcription-polymerase chain reaction (RT-PCR) showed that the mRNA and protein levels of IL-25 and IL-17BR are significantly higher in IPF patients when compared with normal controls. Intranasal instillation of IL-25 to mice markedly induces the expressions of alveolar IL-5 and IL-13. Furthermore, immunohistochemical analysis showed that the main components of the extracellular matrix including collagen I, collagen III and fibronectin are notably induced by IL-25 instillation in lung parenchyma (especially in alveolar epithelial cells [AECs]). Also, IL-25 potentiates the expression of connective tissue growth factor (CTGF) in AECs and the recruitment of lung fibroblast. By using Cell Counting Kit-8 and EDU incorporation assay, we found that IL-25 markedly enhances the proliferation of lung fibroblast. Finally, IL-25 potentiates fibroblast to produce several fibrogenic genes including collagen I/III, fibronectin, CTGF, α smooth muscle (α-SMA) and tissue inhibitor of metalloproteinase (TIMP)-1 as determined by RT-PCR assay. Collectively, we concluded that IL-25 is increased in IPF lungs and contributes to lung fibrosis by directly mediating AECs/fibroblast activation. Impact statement Our work focused on alveolar epithelial cells (AECs)-derived type-2 cytokine (interleukin [IL]-25) in the pathogenesis of idiopathic pulmonary fibrosis (IPF). We showed that IL-25 and IL-17BR (IL-25’s receptor) is upregulated in lung tissues (especially in AECs and lung fibroblasts) of IPF patients and contributes to lung fibrosis by directly activating lung fibroblasts and modulating epithelial–mesenchymal transition (EMT) of AECs. We suggest that IL-25 may be one of the master switches hidden in the milieu of abnormal epithelial–mesenchymal crosstalk. Treatment targeting IL-25 may be the potential and novel method for IPF patients.

scholarly journals Epithelial–Mesenchymal Transition in the Pathogenesis of Idiopathic Pulmonary Fibrosis

Medicina ◽  
2019 ◽  
Vol 55 (4) ◽  
pp. 83 ◽  
Author(s):  
Francesco Salton ◽  
Maria Volpe ◽  
Marco Confalonieri
Keyword(s):  
Epithelial Cells ◽  
Idiopathic Pulmonary Fibrosis ◽  
Pulmonary Fibrosis ◽  
Epithelial Mesenchymal Transition ◽  
Treatment Options ◽  
Alveolar Epithelium ◽  
Alveolar Epithelial Cells ◽  
Mesenchymal Transition ◽  
Alveolar Epithelial ◽  
Serious Disease

Idiopathic pulmonary fibrosis (IPF) is a serious disease of the lung, which leads to extensive parenchymal scarring and death from respiratory failure. The most accepted hypothesis for IPF pathogenesis relies on the inability of the alveolar epithelium to regenerate after injury. Alveolar epithelial cells become apoptotic and rare, fibroblasts/myofibroblasts accumulate and extracellular matrix (ECM) is deposited in response to the aberrant activation of several pathways that are physiologically implicated in alveologenesis and repair but also favor the creation of excessive fibrosis via different mechanisms, including epithelial–mesenchymal transition (EMT). EMT is a pathophysiological process in which epithelial cells lose part of their characteristics and markers, while gaining mesenchymal ones. A role for EMT in the pathogenesis of IPF has been widely hypothesized and indirectly demonstrated; however, precise definition of its mechanisms and relevance has been hindered by the lack of a reliable animal model and needs further studies. The overall available evidence conceptualizes EMT as an alternative cell and tissue normal regeneration, which could open the way to novel diagnostic and prognostic biomarkers, as well as to more effective treatment options.

Release of biologically active TGF-β1 by alveolar epithelial cells results in pulmonary fibrosis

2003 ◽  
Vol 285 (3) ◽  
pp. L527-L539 ◽  
Author(s):  
Ying Dong Xu ◽  
Jiesong Hua ◽  
Alice Mui ◽  
Robert O'Connor ◽  
Gary Grotendorst ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Pulmonary Fibrosis ◽  
Transforming Growth Factor ◽  
Inflammatory Cells ◽  
Alveolar Epithelial Cells ◽  
Biologically Active ◽  
Aberrant Expression ◽  
Alveolar Epithelial ◽  
Fibrotic Lung Disease ◽  
Tgf Β1

Idiopathic pulmonary fibrosis (IPF) is a progressive fatal fibrotic lung disease. Transforming growth factor (TGF)-β1 is present in a biologically active conformation in the epithelial cells lining lesions with advanced IPF. To determine the role of aberrant expression of biologically active TGF-β1 by alveolar epithelial cells (AECs), the AECs of explanted normal rat lungs were transfected with the TGF-β1 gene using the retrovirus pMX-L-s223,225-TGF-β1. In situ hybridization using a digoxigenin-labeled cDNA of the puromycin resistance gene contained in the pMX demonstrated that pMX-L-s233,225-TGF-β1 was selectively transfected into AECs of the explants. Conditioned media overlying explants obtained 7 days after being treated with pMX-L-s223,225-TGF-β1 contained 14.5 ± 3.15 pg/ml of active TGF-β1. With the use of Masson's trichrome staining of explant sections obtained 14 days after transfection, there were lesions similar to those in IPF, characterized by type II AEC hyperplasia, interstitial thickening, extensive increase in interstitial and subepithelial collagen, an increase in the number of fibroblasts, and areas resembling fibroblast buds. Collagens I, III, IV, and V and fibronectin were increased in explants treated with pMX-L-s223,225-TGF-β1. The findings in the current study suggest that IPF may be a disorder of epithelial cells and not inflammatory cells.

scholarly journals miR-34 miRNAs Regulate Cellular Senescence in Type II Alveolar Epithelial Cells of Patients with Idiopathic Pulmonary Fibrosis

PLoS ONE ◽  
2016 ◽  
Vol 11 (6) ◽  
pp. e0158367 ◽  
Author(s):  
Supparerk Disayabutr ◽  
Eun Kyung Kim ◽  
Seung-Ick Cha ◽  
Gary Green ◽  
Ram P. Naikawadi ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Idiopathic Pulmonary Fibrosis ◽  
Pulmonary Fibrosis ◽  
Cellular Senescence ◽  
Alveolar Epithelial Cells ◽  
Type Ii ◽  
Alveolar Epithelial

scholarly journals The NLRP3-Inflammasome-Caspase-1 Pathway Is Upregulated in Idiopathic Pulmonary Fibrosis and Acute Exacerbations and Is Inducible by Apoptotic A549 Cells

2021 ◽  
Vol 12 ◽  
Author(s):  
Benedikt Jäger ◽  
Benjamin Seeliger ◽  
Oliver Terwolbeck ◽  
Gregor Warnecke ◽  
Tobias Welte ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Idiopathic Pulmonary Fibrosis ◽  
Pulmonary Fibrosis ◽  
Nlrp3 Inflammasome ◽  
Cathepsin B ◽  
A549 Cells ◽  
Alveolar Epithelial Cells ◽  
Alveolar Epithelial ◽  
Caspase 1 ◽  
Acute Exacerbations

Idiopathic pulmonary fibrosis (IPF) is a relentlessly progressive disease harboring significant morbidity and mortality despite recent advances in therapy. Regardless of disease severity acute exacerbations (IPF-AEs) may occur leading to considerable loss of function and are the leading cause of death in IPF. Histologic features of IPF-AE are very similar to acute respiratory distress syndrome (ARDS), but the underlying mechanisms are incompletely understood. We investigated the role of the NLRP3 inflammasome in IPF and IPF-AE. Bronchoalveolar lavage (BAL) cells were sampled from patients with IPF (n = 32), IPF-AE (n = 10), ARDS (n = 7) and healthy volunteers (HV, n = 37) and the NLRP3-inflammasome was stimulated in-vitro. We found the NLRP3 inflammasome to be hyper-inducible in IPF compared to HV with increased IL-1ß and pro-IL-1ß levels on ELISA upon stimulation as well as increased caspase-1 activity measured by caspase-1p20 immunoblotting. In IPF-AE, IL-1ß was massively elevated to an extent similar to ARDS. To evaluate potential mechanisms, we co-cultured BAL cells with radiated A549 cells (a model to simulate apoptotic alveolar epithelial cells), which led to increased NLRP3 mRNA expression and increased caspase-1 dependent IL-1ß production. In the presence of a reactive oxygen species (ROS) inhibitor (diphenyleneiodonium) and a cathepsin B inhibitor (E64D), NLRP3 expression was suppressed indicating that induction of NLRP3 activation following efferocytosis of apoptotic A549 cells is mediated via ROS and cathepsin-B. In summary, we present evidence of involvement of the NLRP3 inflammasome-caspase pathway in the pathogenesis of IPF-AE, similarly to ARDS, which may be mediated by efferocytosis of apoptotic alveolar epithelial cells in IPF.

scholarly journals Origin of Myofibroblasts in Lung Fibrosis

2020 ◽  
Vol 1 (4) ◽  
pp. 155-162
Author(s):  
CF Hung
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Epithelial Cells ◽  
Lung Fibrosis ◽  
Cell Types ◽  
Mesenchymal Cells ◽  
Lineage Tracing ◽  
Alveolar Epithelial Cells ◽  
Multiple Sources ◽  
Alveolar Epithelial

Abstract Purpose of Review In this brief review, we will highlight important observational and experimental data in the literature that address the origin of scar-forming cells in lung fibrosis. Recent Findings Several cellular sources of activated scar-forming cells (myofibroblasts) have been postulated including alveolar epithelial cells; circulating fibrocytes; and lung stromal cell subpopulations including resident fibroblasts, pericytes, and resident mesenchymal stem cells. Recent advances in lineage-tracing models, however, fail to provide experimental evidence for epithelial and fibrocyte origins of lung myofibroblasts. Resident mesenchymal cells of the lung, which include various cell types including resident fibroblasts, pericytes, and resident mesenchymal stem cells, appear to be important sources of myofibroblasts in murine models of lung injury and fibrosis. Summary Lung myofibroblasts likely originate from multiple sources of lung-resident mesenchymal cells. Their relative contributions may vary depending on the type of injury. Although lineage-tracing experiments have failed to show significant contribution from epithelial cells or fibrocytes, they may play important functional roles in myofibroblast activation through paracrine signaling.

scholarly journals TM4SF5-mediated CD44v8-10 splicing variant promotes survival of type II alveolar epithelial cells during idiopathic pulmonary fibrosis

2019 ◽  
Vol 10 (9) ◽  
Author(s):  
Ji Eon Kim ◽  
Hye-Jin Kim ◽  
Jae Woo Jung ◽  
Dae-Geun Song ◽  
Dasomi Park ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Idiopathic Pulmonary Fibrosis ◽  
Pulmonary Fibrosis ◽  
Cell Fate ◽  
Alveolar Epithelial Cells ◽  
Lung Epithelial Cells ◽  
Type I ◽  
Type Ii ◽  
Alveolar Epithelial ◽  
Primary Mouse

Abstract Reactive oxygen species (ROS) regulate cell fate, although signaling molecules that regulate ROS hormesis remain unclear. Here we show that transmembrane 4 L six family member 5 (TM4SF5) in lung epithelial cells induced the alternatively spliced CD44v8-10 variant via an inverse ZEB2/epithelial splicing regulatory proteins (ESRPs) linkage. TM4SF5 formed complexes with the cystine/glutamate antiporter system via TM4SF5- and CD44v8-10-dependent CD98hc plasma-membrane enrichment. Dynamic TM4SF5 binding to CD98hc required CD44v8-10 under ROS-generating inflammatory conditions. TM4SF5 and CD44v8-10 upregulated cystine/glutamate antiporter activity and intracellular glutathione levels, leading to ROS modulation for cell survival. Tm4sf5-null mice exhibited attenuated bleomycin-induced pulmonary fibrosis with lower CD44v8-10 and ESRPs levels than wild-type mice. Primary mouse alveolar epithelial cells (AECs) revealed type II AECs (AECII), but not type I, to adapt the TM4SF5-mediated characteristics, suggesting TM4SF5-mediated AECII survival following AECI injury during idiopathic pulmonary fibrosis (IPF). Thus, the TM4SF5-mediated CD44v8-10 splice variant could be targeted against IPF.

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