Captopril inhibits apoptosis in human lung  epithelial cells: a potential antifibrotic mechanism

The angiotensin-converting enzyme inhibitor captopril has been shown to inhibit fibrogenesis in the lung, but the mechanisms underlying this action are unclear. Apoptosis of lung epithelial cells is believed to be involved in the pathogenesis of pulmonary fibrosis. For these reasons, we studied the effect of captopril on Fas-induced apoptosis in a human lung epithelial cell line. Monoclonal antibodies that activate the Fas receptor induced epithelial cell apoptosis as detected by chromatin condensation, nuclear fragmentation, DNA fragmentation, and increased activities of caspase-1 and -3. Apoptosis was not induced by isotype-matched nonimmune mouse immunoglobulins or nonactivating anti-Fas monoclonal antibodies. When applied simultaneously with anti-Fas antibodies, 50 ng/ml of captopril completely abrogated apoptotic indexes based on morphology, DNA fragmentation, and inducible caspase-1 activity and significantly decreased the inducible activity of caspase-3. Inhibition of apoptosis by captopril was concentration dependent, with an IC50 of 70 pg/ml. These data suggest that the inhibitory actions of captopril on pulmonary fibrosis may be related to prevention of lung epithelial cell apoptosis.

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Dexamethasone inhibits lung epithelial cell apoptosis induced by IFN-γ and Fas

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.1997.273.5.l921 ◽

1997 ◽

Vol 273 (5) ◽

pp. L921-L929 ◽

Cited By ~ 26

Author(s):

Long-Ping Wen ◽

Kamyar Madani ◽

Jimothy A. Fahrni ◽

Steven R. Duncan ◽

Glenn D. Rosen

Keyword(s):

Epithelial Cell ◽

Epithelial Cells ◽

Inflammatory Response ◽

Cell Apoptosis ◽

Inhibitor Of Apoptosis ◽

Induced Expression ◽

Lung Epithelial ◽

Epithelial Cell Apoptosis ◽

Ifn Γ ◽

Induced Apoptosis

Lung epithelium plays a central role in modulation of the inflammatory response and in lung repair. Airway epithelial cells are targets in asthma, viral infection, acute lung injury, and fibrotic lung disease. Activated T lymphocytes release cytokines such as interferon-γ (IFN-γ) that can cooperate with apoptotic signaling pathways such as the Fas-APO-1 pathway to induce apoptosis of damaged epithelial cells. We report that IFN-γ alone and in combination with activation of the Fas pathway induced apoptosis in A549 lung epithelial cells. Interestingly, the corticosteroid dexamethasone was the most potent inhibitor of IFN-γ- and IFN-γ plus anti-Fas-induced apoptosis. IFN-γ induced expression of an effector of apoptosis, the cysteine protease interleukin-1β-converting enzyme, in A549 cells. Dexamethasone, in contrast, induced expression of an inhibitor of apoptosis, human inhibitor of apoptosis (hIAP-1), also known as cIAP2. We suggest that the inhibition of epithelial cell apoptosis by corticosteroids may be one mechanism by which they suppress the inflammatory response.

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TNF Family Cytokines Induce Distinct Cell Death Modalities in the A549 Human Lung Epithelial Cell Line when Administered in Combination with Ricin Toxin

Toxins ◽

10.3390/toxins11080450 ◽

2019 ◽

Vol 11 (8) ◽

pp. 450 ◽

Cited By ~ 5

Author(s):

Hodges ◽

Kempen ◽

McCaig ◽

Parker ◽

Mantis ◽

...

Keyword(s):

Cell Death ◽

Epithelial Cell ◽

Epithelial Cells ◽

Human Lung ◽

Lung Epithelial Cells ◽

Lung Epithelial Cell ◽

Distinct Cell ◽

Tnf Α ◽

Lung Epithelial ◽

Human Lung Epithelial Cells

Ricin is a member of the ribosome-inactivating protein (RIP) family of toxins and is classified as a biothreat agent by the Centers for Disease Control and Prevention (CDC). Inhalation, the most potent route of toxicity, triggers an acute respiratory distress-like syndrome that coincides with near complete destruction of the lung epithelium. We previously demonstrated that the TNF-related apoptosis-inducing ligand (TRAIL; CD253) sensitizes human lung epithelial cells to ricin-induced death. Here, we report that ricin/TRAIL-mediated cell death occurs via apoptosis and involves caspases -3, -7, -8, and -9, but not caspase-6. In addition, we show that two other TNF family members, TNF-α and Fas ligand (FasL), also sensitize human lung epithelial cells to ricin-induced death. While ricin/TNF-α- and ricin/FasL-mediated killing of A549 cells was inhibited by the pan-caspase inhibitor, zVAD-fmk, evidence suggests that these pathways were not caspase-dependent apoptosis. We also ruled out necroptosis and pyroptosis. Rather, the combination of ricin plus TNF-α or FasL induced cathepsin-dependent cell death, as evidenced by the use of several pharmacologic inhibitors. We postulate that the effects of zVAD-fmk were due to the molecule’s known off-target effects on cathepsin activity. This work demonstrates that ricin-induced lung epithelial cell killing occurs by distinct cell death pathways dependent on the presence of different sensitizing cytokines, TRAIL, TNF-α, or FasL.

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Dexamethasone induces senescence of lung epithelial cells and augments TGF-β1-mediated production of the fibrosis mediator serpin E1 (plasminogen activator inhibitor-1)

10.1101/2021.11.29.470337 ◽

2021 ◽

Author(s):

Francesca Louise Longhorne ◽

Holly N Wilkinson ◽

Matthew J Hardman ◽

Simon Hart

Keyword(s):

Epithelial Cells ◽

Pulmonary Fibrosis ◽

Cellular Senescence ◽

Human Lung ◽

Lung Epithelial Cells ◽

Lung Fibroblasts ◽

Plasminogen Activator Inhibitor 1 ◽

Lung Epithelial ◽

Tgf Β1 ◽

Pai 1

Background: Idiopathic pulmonary fibrosis (IPF) is a progressive, incurable scarring disease of the lungs with a prognosis worse than most cancers. Pathologically, IPF is characterised by upregulation of the pro-fibrotic cytokine transforming growth factor-β1 (TGF-β1), activation of fibroblasts, and deposition of collagen in the alveolar interstitium. Recent evidence has highlighted the role of senescent type 2 alveolar epithelial cells in the pathogenesis of IPF. In a clinical trial, a treatment regimen containing a corticosteroid drug accelerated pulmonary fibrosis leading to more hospitalizations and deaths, particularly in patients with telomere shortening which drives cellular senescence. Aim: To investigate the potential pro-fibrotic actions of corticosteroids on lung epithelial cells in vitro, including effects on cellular senescence and interactions with TGF-β1. Methods: The synthetic glucocorticoid dexamethasone (DEX) was incubated with A549 and BEAS-2B human lung epithelial cells in the presence or absence of TGF-β1. Cellular senescence was assessed by morphology, senescence-associated beta-galactosidase (SA β-Gal) expression, and qPCR for transcription of senescence-associated molecular markers. Conditioned media were screened for growth factors and cytokines and cultured with human lung fibroblasts. An IPF lung tissue RNA array dataset was re-analysed with a focus on senescence markers. Results: DEX induced senescence in lung epithelial cells associated with increased p21 (CDKN1A) expression independently of p16 (CDKN2A) or p53 (TP53). DEX amplified upregulation of the pro-fibrotic mediator serpin E1/plasminogen activator inhibitor-1 (PAI-1) in the presence of TGF-β1. The senescence-associated secretory phenotype from lung epithelial cells treated with DEX plus TGF-β1-treated contained increased concentrations of GM-CSF and IL-6 and when incubated with primary human lung fibroblasts there were trends to increased senescence and production of fibrosis markers. Upregulation of senescence markers was demonstrated by analysis of an IPF transcriptomic dataset. Discussion: DEX induces senescence in lung epithelial cell lines in vitro and interacts with TGF-β1 to amplify production of the pro-fibrotic mediator serpin E1 (PAI-1). This may be a mechanism by which corticosteroids promote pulmonary fibrosis in susceptible individuals. Serpin E1/PAI-1 is a potential druggable target in pulmonary fibrosis.

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In Vitro Studies on the Impact of Ergothioneine on Idiopathic Pulmonary Fibrosis Markers in Human Lung Epithelial Cells

10.1164/ajrccm-conference.2019.199.1_meetingabstracts.a2141 ◽

2019 ◽

Author(s):

C.C. Koay ◽

M.A. Selo ◽

C.G. Clerkin ◽

C. Ehrhardt

Keyword(s):

Epithelial Cells ◽

Idiopathic Pulmonary Fibrosis ◽

Pulmonary Fibrosis ◽

Human Lung ◽

In Vitro Studies ◽

Lung Epithelial Cells ◽

Lung Epithelial ◽

The Impact ◽

Human Lung Epithelial Cells

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Impact of ergothioneine on idiopathic pulmonary fibrosis markers in human lung epithelial cells in vitro

The FASEB Journal ◽

10.1096/fasebj.2019.33.1_supplement.127.11 ◽

2019 ◽

Vol 33 (S1) ◽

Author(s):

Carsten Ehrhardt ◽

Aaron Koay ◽

Caoimhe Clerkin ◽

Mohammed Ali Selo

Keyword(s):

Epithelial Cells ◽

Idiopathic Pulmonary Fibrosis ◽

Pulmonary Fibrosis ◽

Human Lung ◽

Lung Epithelial Cells ◽

Lung Epithelial ◽

Human Lung Epithelial Cells

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SARS-CoV-2 ORF8 Forms Intracellular Aggregates and Inhibits IFNγ-Induced Antiviral Gene Expression in Human Lung Epithelial Cells

Frontiers in Immunology ◽

10.3389/fimmu.2021.679482 ◽

2021 ◽

Vol 12 ◽

Author(s):

Hua Geng ◽

Saravanan Subramanian ◽

Longtao Wu ◽

Heng-Fu Bu ◽

Xiao Wang ◽

...

Keyword(s):

Cell Proliferation ◽

Epithelial Cell ◽

Epithelial Cells ◽

Viral Infection ◽

Human Lung ◽

Lung Epithelial Cells ◽

Lung Epithelial Cell ◽

Accessory Protein ◽

Epithelial Cell Proliferation ◽

Lung Epithelial

Infection with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes COVID-19, a disease that involves significant lung tissue damage. How SARS-CoV-2 infection leads to lung injury remains elusive. The open reading frame 8 (ORF8) protein of SARS-CoV-2 (ORF8SARS-CoV-2) is a unique accessory protein, yet little is known about its cellular function. We examined the cellular distribution of ORF8SARS-CoV-2 and its role in the regulation of human lung epithelial cell proliferation and antiviral immunity. Using live imaging and immunofluorescent staining analyses, we found that ectopically expressed ORF8SARS-CoV-2 forms aggregates in the cytosol and nuclear compartments of lung epithelial cells. Using in silico bioinformatic analysis, we found that ORF8SARS-CoV-2 possesses an intrinsic aggregation characteristic at its N-terminal residues 1-18. Cell culture did not reveal any effects of ORF8SARS-CoV-2 expression on lung epithelial cell proliferation and cell cycle progression, suggesting that ORF8SARS-CoV-2 aggregates do not affect these cellular processes. Interestingly, ectopic expression of ORF8SARS-CoV-2 in lung epithelial cells suppressed basal expression of several antiviral molecules, including DHX58, ZBP1, MX1, and MX2. In addition, expression of ORF8SARS-CoV-2 attenuated the induction of antiviral molecules by IFNγ but not by IFNβ in lung epithelial cells. Taken together, ORF8SARS-CoV-2 is a unique viral accessory protein that forms aggregates when expressing in lung epithelial cells. It potently inhibits the expression of lung cellular anti-viral proteins at baseline and in response to IFNγ in lung epithelial cells, which may facilitate SARS-CoV-2 escape from the host antiviral innate immune response during early viral infection. In addition, it seems that formation of ORF8SARS-CoV-2 aggregate is independent from the viral infection. Thus, it would be interesting to examine whether any COVID-19 patients exhibit persistent ORF8 SARS-CoV-2 expression after recovering from SARS-CoV-2 infection. If so, the pathogenic effect of prolonged ORF8SARS-CoV-2 expression and its association with post-COVID symptoms warrant investigation in the future.

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Histone Deacetylases Promote ER Stress Induced Epithelial Mesenchymal Transition in Human Lung Epithelial Cells

Cellular Physiology and Biochemistry ◽

10.1159/000489367 ◽

2018 ◽

Vol 46 (5) ◽

pp. 1821-1834 ◽

Cited By ~ 6

Author(s):

Daishun Liu ◽

Honglan Zhu ◽

Ling Gong ◽

Shenglan Pu ◽

Yang Wu ◽

...

Keyword(s):

Epithelial Cells ◽

Pulmonary Fibrosis ◽

Er Stress ◽

Histone Deacetylases ◽

Human Lung ◽

A549 Cells ◽

Lung Epithelial Cells ◽

Smad Pathway ◽

Mesenchymal Transition ◽

Lung Epithelial

Background/Aims: Epithelial to mesenchymal transition (EMT) is a crucial process involved in pulmonary fibrosis. This study aimed to explore the role of histone deacetylases (HDACs) and endoplasmic reticulum (ER) stress in EMT in human lung epithelial cells. Methods: Human lung adenocarcinoma A549 cells were treated with bleomycin and tunicamycin to induce EMT. The proliferation of A549 cells was detected by MTT assay. The expression of HDACs and EMT markers was detected by PCR and Western blot analysis. The secretion of TGF-β1 and collagen I was examined by ELISA. Results: A549 cells switched from a cobblestone-like appearance to an elongated fibroblast like appearance after exposure to tunicamycin or bleomycin, accompanied by increased expression of N-cadherin, α-SMA and Collagen I. Meanwhile, GRP78 was upregulated in A549 cells exposed to tunicamycin or bleomycin. These changes induced by tunicamycin or bleomycin could be abrogated by 4-PBA. Moreover, tunicamycin and bleomycin promoted the expression of HDAC2 and HDAC6, and HDACs inhibitor SAHA abrogated the morphological and biochemical changes in A549 cells. 4-PBA and SAHA inhibited the upregulation of pulmonary fibrosis factors TGF-β1 and IL-32 and the activation of Smad pathway induced by tunicamycin or bleomycin. Conclusions: We provide the first evidence that tunicamycin and bleomycin induce ER stress and EMT in lung epithelial cells via the upregulation of HDACs. HDACs inhibitor could inhibit ER stress induced upregulation of pulmonary fibrosis factors and the activation of Smad pathway. HDACs inhibitors are promising agents for the therapy of pulmonary fibrosis.

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PKCδ/midkine pathway drives hypoxia-induced proliferation and differentiation of human lung epithelial cells

AJP Cell Physiology ◽

10.1152/ajpcell.00351.2013 ◽

2014 ◽

Vol 306 (7) ◽

pp. C648-C658 ◽

Cited By ~ 13

Author(s):

Hanying Zhang ◽

Miyako Okamoto ◽

Evgeniy Panzhinskiy ◽

W. Michael Zawada ◽

Mita Das

Keyword(s):

Epithelial Cell ◽

Epithelial Cells ◽

Lung Diseases ◽

Human Lung ◽

Culture Media ◽

Alveolar Epithelial Cells ◽

Lung Epithelial Cells ◽

Lung Epithelial ◽

Proliferation And Differentiation ◽

Human Lung Epithelial Cells

Epithelial cells are key players in the pathobiology of numerous hypoxia-induced lung diseases. The mechanisms mediating such hypoxic responses of epithelial cells are not well characterized. Earlier studies reported that hypoxia stimulates protein kinase C (PKC)δ activation in renal cancer cells and an increase in expression of a heparin-binding growth factor, midkine (MK), in lung alveolar epithelial cells. We reasoned that hypoxia might regulate MK levels via a PKCδ-dependent pathway and hypothesized that PKCδ-driven MK expression is required for hypoxia-induced lung epithelial cell proliferation and differentiation. Replication of human lung epithelial cells (A549) was significantly increased by chronic hypoxia (1% O2) and was dependent on expression of PKCδ. Hypoxia-induced proliferation of epithelial cells was accompanied by translocation of PKCδ from Golgi into the nuclei. Marked attenuation in MK protein levels by rottlerin, a pharmacological antagonist of PKC, and by small interfering RNA-targeting PKCδ, revealed that PKCδ is required for MK expression in both normoxic and hypoxic lung epithelial cells. Sequestering MK secreted into the culture media with a neutralizing antibody reduced hypoxia-induced proliferation demonstrating that an increase in MK release from cells is linked with epithelial cell division under hypoxia. In addition, recombinant MK accelerated transition of hypoxic epithelial cells to cells of mesenchymal phenotype characterized by elongated morphology and increased expression of mesenchymal markers, α-smooth muscle actin, and vimentin. We conclude that PKCδ/MK axis mediates hypoxic proliferation and differentiation of lung epithelial cells. Manipulation of PKCδ and MK activity in epithelial cells might be beneficial for the treatment of hypoxia-mediated lung diseases.

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