scholarly journals Resetting proteostasis with ISRIB promotes epithelial differentiation to attenuate pulmonary fibrosis

2021 ◽  
Vol 118 (20) ◽  
pp. e2101100118
Author(s):  
Satoshi Watanabe ◽  
Nikolay S. Markov ◽  
Ziyan Lu ◽  
Raul Piseaux Aillon ◽  
Saul Soberanes ◽  
...  
Keyword(s):  
Pulmonary Fibrosis ◽  
Lung Fibrosis ◽  
Alveolar Epithelium ◽  
Protein Translation ◽  
Alveolar Type ◽  
Fatal Disease ◽  
Epithelial Repair ◽  
Old Mice

Pulmonary fibrosis is a relentlessly progressive and often fatal disease with a paucity of available therapies. Genetic evidence implicates disordered epithelial repair, which is normally achieved by the differentiation of small cuboidal alveolar type 2 (AT2) cells into large, flattened alveolar type 1 (AT1) cells as an initiating event in pulmonary fibrosis pathogenesis. Using models of pulmonary fibrosis in young adult and old mice and a model of adult alveologenesis after pneumonectomy, we show that administration of ISRIB, a small molecule that restores protein translation by EIF2B during activation of the integrated stress response (ISR), accelerated the differentiation of AT2 into AT1 cells. Accelerated epithelial repair reduced the recruitment of profibrotic monocyte-derived alveolar macrophages and ameliorated lung fibrosis. These findings suggest a dysfunctional role for the ISR in regeneration of the alveolar epithelium after injury with implications for therapy.

Urokinase plasminogen activator released by alveolar epithelial cells modulates alveolar epithelial repair in vitro

2005 ◽  
Vol 94 (12) ◽  
pp. 1257-1264 ◽  
Author(s):  
Coretta Van Leer ◽  
Monika Stutz ◽  
André Haeberli ◽  
Thomas Geiser
Keyword(s):  
Epithelial Cells ◽  
Pulmonary Fibrosis ◽  
Wound Repair ◽  
Alveolar Epithelium ◽  
Alveolar Epithelial Cells ◽  
Alveolar Type ◽  
Epithelial Repair ◽  
Alveolar Epithelial ◽  
Fibrin Matrix

SummaryIntra-alveolar fibrin is formed following lung injury and inflammation and may contribute to the development of pulmonary fibrosis. Fibrin turnover is altered in patients with pulmonary fibrosis, resulting in intra-alveolar fibrin accumulation, mainly due to decreased fibrinolysis. Alveolar type II epithelial cells (AEC) repair the injured alveolar epithelium by migrating over the provisional fibrin matrix. We hypothesized that repairing alveolar epithelial cells modulate the underlying fibrin matrix by release of fibrinolytic activity, and that the degree of fibrinolysis modulates alveolar epithelial repair on fibrin. To test this hypothesis we studied alveolar epithelial wound repair in vitro using a modified epithelial wound repair model with human A549 alveolar epithelial cells cultured on a fibrin matrix. In presence of the inflammatory cytokine interleukin-1β, wounds increase by 800% in 24 hours mainly due to detachment of the cells, whereas in serum-free medium wound areas decreases by 22.4 ± 5.2 % (p<0.01). Increased levels of D-dimer, FDP and uPA in the cell supernatant of IL-1β-stimulated A549 epithelial cells indicate activation of fibrinolysis by activation of the plasmin system. In presence of low concentrations of fibrinolysis inhibitors, including specific blocking anti-uPA antibodies, alveolar epithelial repair in vitro was improved, whereas in presence of high concentrations of fibrinolysis inhibitors, a decrease was observed mainly due to decreased spreading and migration of cells. These findings suggest the existence of a fibrinolytic optimum at which alveolar epithelial repair in vitro is most efficient. In conclusion, uPA released by AEC alters alveolar epithelial repair in vitro by modulating the underlying fibrin matrix.

Transformation of alveolar Type 2 cells to Type 1 cells following exposure to NO2

1975 ◽  
Vol 22 (1) ◽  
pp. 142-150 ◽  
Author(s):  
Michael J. Evans ◽  
Linda J. Cabral ◽  
Robert J. Stephens ◽  
Gustave Freeman
Keyword(s):  
Alveolar Type

scholarly journals Ultra- and micro-structural changes of respiratory tracts in SARS-CoV-2 infected Syrian hamsters

2021 ◽  
Vol 52 (1) ◽  
Author(s):  
Myeon-Sik Yang ◽  
Byung Kwan Oh ◽  
Daram Yang ◽  
Eun Young Oh ◽  
Yeonhwa Kim ◽  
...  
Keyword(s):  
Structural Changes ◽  
Alveolar Epithelium ◽  
Inflammatory Cells ◽  
Alveolar Wall ◽  
Lamellar Bodies ◽  
Electron Microscopic ◽  
Syrian Hamsters ◽  
Electron Lucent

AbstractThe severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) pandemic is causing a global crisis. It is still unresolved. Although many therapies and vaccines are being studied, they are still in their infancy. As this pandemic continues, rapid and accurate research for the development of therapies and vaccines is needed. Therefore, it is necessary to understand characteristics of diseases caused by SARS-CoV-2 through animal models. Syrian hamsters are known to be susceptible to SARS-CoV-2. They were intranasally inoculated with SARS-CoV-2. At 2, 4, 8, 12, and 16 days post-infection (dpi), these hamsters were euthanized, and tissues were collected for ultrastructural and microstructural examinations. Microscopic lesions were prominent in the upper and lower respiratory tracts from 2 and 4 dpi groups, respectively. The respiratory epithelium in the trachea, bronchiole, and alveolar showed pathological changes. Inflammatory cells including neutrophils, lymphocytes, macrophages, and eosinophils were infiltrated in/around tracheal lamina propria, pulmonary vessels, alveoli, and bronchiole. In pulmonary lesions, alveolar wall was thickened with infiltrated inflammatory cells, mainly neutrophils and macrophages. In the trachea, epithelial damages started from 2 dpi and recovered from 8 dpi, consistent with microscopic results, High levels of SARS-CoV-2 nucleoprotein were detected at 2 dpi and 4 dpi. In the lung, lesions were most severe at 8 dpi. Meanwhile, high levels of SARS-CoV-2 were detected at 4 dpi. Electron microscopic examinations revealed cellular changes in the trachea epithelium and alveolar epithelium such as vacuolation, sparse micro-organelle, and poor cellular margin. In the trachea epithelium, the number of cytoplasmic organelles was diminished, and small vesicles were prominent from 2 dpi. Some of these electron-lucent vesicles were filled with virion particles. From 8 dpi, the trachea epithelium started to recover. Because of shrunken nucleus and swollen cytoplasm, the N/C ratio of type 2 pneumocyte decreased at 8 and 12 dpi. From 8 dpi, lamellar bodies on type 2 pneumocyte cytoplasm were increasingly observed. Their number then decreased from 16 dpi. However, there was no significant change in type 1 pneumocyte. Viral vesicles were only observed in the cytoplasm of type 2 pneumocyte. In conclusion, ultra- and micro-structural changes presented in this study may provide useful information for SARS-CoV-2 studies in various fields.

scholarly journals Fibrinolytic niche is requested for alveolar type 2 cell-mediated alveologenesis and injury repair

2020 ◽  
Author(s):  
Ali Gibran ◽  
Runzhen Zhao ◽  
Mo Zhang ◽  
Krishan G. Jain ◽  
Jianjun Chang ◽  
...  
Keyword(s):  
Alveolar Epithelium ◽  
Influenza Viruses ◽  
Alveolar Type ◽  
Differential Rate ◽  
Alveolar Epithelial ◽  
Proliferation And Differentiation ◽  
Marked Suppression

ABSTRACTCOVID-19, SARS, and MERS are featured by fibrinolytic dysfunction. To test the role of the fibrinolytic niche in the regeneration of alveolar epithelium, we compared the self-renewing capacity of alveolar epithelial type 2 (AT2) cells and its differentiation to AT1 cells between wild type (wt) and fibrinolytic niche deficient mice (Plau−/− and Serpine1Tg). A significant reduction in both proliferation and differentiation of deficient AT2 cells was observed in vivo and in 3D organoid cultures. This decrease was mainly restored by uPA derived A6 peptide, a binding fragment to CD44 receptors. The proliferative and differential rate of CD44+ AT2 cells was greater than that of CD44− controls. There was a reduction in transepithelial ion transport in deficient monolayers compared to wt cells. Moreover, we found a marked suppression in total AT2 cells and CD44+ subpopulation in lungs from brain dead patients with acute respiratory distress syndrome (ARDS) and a mouse model infected by influenza viruses. Thus, we demonstrate that the fibrinolytic niche can regulate AT2-mediated homeostasis and regeneration via a novel uPA-A6-CD44+-ENaC cascade.

scholarly journals Type-1 IFN primed monocytes in pathogenesis of idiopathic pulmonary fibrosis

2020 ◽  
Author(s):  
Emily Fraser ◽  
Laura Denney ◽  
Karl Blirando ◽  
Chaitanya Vuppusetty ◽  
Agne Antanaviciute ◽  
...  
Keyword(s):  
Idiopathic Pulmonary Fibrosis ◽  
Pulmonary Fibrosis ◽  
Immune Cells ◽  
Therapeutic Target ◽  
Lung Fibrosis ◽  
Ex Vivo ◽  
Treatment Options ◽  
Gene Expression Signature ◽  
Severe Form

ABSTRACTIdiopathic pulmonary fibrosis (IPF) is the most severe form of lung fibrosis. It is progressive, and has an extremely poor outcome and limited treatment options. The disease exclusively affects the lungs, and thus less attention has been focused on blood-borne immune cells. which could be a more effective therapeutic target than lung-based cells. Here, we questioned if circulating monocytes, which has been shown to be increased in IPF, bore abnormalities that might contribute to its pathogenesis. We found that levels of circulating monocytes correlated directly with the extent of fibrosis in the lungs, and increased further during acute clinical deterioration. Monocytes in IPF were phenotypically distinct, displaying increased expression of CD64, a type 1 IFN gene expression signature and a greater magnitude of type 1 IFN response when stimulated. These abnormalities were accompanied by markedly raised CSF-1 levels in the serum, prolonged survival of monocytes ex vivo, and increased numbers of monocytes in lung tissue. Our study defines the key monocytic abnormalities in IPF, proposing type 1 IFN-primed monocytes as a potential driver of an aberrant repair response and fibrosis. It provides a rationale for targeting monocytes and identifies monocytic CD64 as a potential specific therapeutic target for IPF.

scholarly journals Arctigenin Suppressed Epithelial-Mesenchymal Transition Through Wnt3a/β-Catenin Pathway in PQ-Induced Pulmonary Fibrosis

2020 ◽  
Vol 11 ◽  
Author(s):  
Fei Gao ◽  
Yun Zhang ◽  
Zhizhou Yang ◽  
Mengmeng Wang ◽  
Zhiyi Zhou ◽  
...  
Keyword(s):  
Pulmonary Fibrosis ◽  
Signaling Pathway ◽  
Lung Fibrosis ◽  
Epithelial Mesenchymal Transition ◽  
A549 Cells ◽  
Underlying Mechanism ◽  
Alveolar Type ◽  
Mesenchymal Transition

Arctigenin (ATG), a major bioactive substance of Fructus Arctii, counters renal fibrosis; however, whether it protects against paraquat (PQ)-induced lung fibrosis remains unknown. The present study was to determine the effect of ATG on PQ-induced lung fibrosis in a mouse model and the underlying mechanism. Firstly, we found that ATG suppressed PQ-induced pulmonary fibrosis by blocking the epithelial-mesenchymal transition (EMT). ATG reduced the expressions of Vimentin and α-SMA (lung fibrosis markers) induced by PQ and restored the expressions of E-cadherin and Occludin (two epithelial markers) in vivo and in vitro. Besides, the Wnt3a/β-catenin signaling pathway was significantly activated in PQ induced pulmonary fibrosis. Further analysis showed that pretreatment of ATG profoundly abrogated PQ-induced EMT-like phenotypes and behaviors in A549 cells. The Wnt3a/β-catenin signaling pathway was repressed by ATG treatment. The overexpression of Wnt3a could weaken the therapeutic effect of ATG in A549 cells. These findings suggested that ATG could serve as a new therapeutic candidate to inhibit or even reverse EMT-like changes in alveolar type II cells during PQ-induced lung fibrosis, and unraveled that the Wnt3a/β-catenin pathway might be a mechanistic tool for ATG to control pulmonary fibrosis.

scholarly journals H 2 0 2 regulates lung ENaC via ubiquitin‐like protein Nedd8 in alveolar type 1 and type 2 cells.

2013 ◽  
Vol 27 (S1) ◽  
Author(s):  
Nicholle M. Johnson ◽  
Charles A. Downs ◽  
Lisa H. Kreiner ◽  
My N. Helms
Keyword(s):  
Alveolar Type
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