scholarly journals Assessment of Alveolar Macrophage Dysfunction Using an in vitro Model of Acute Respiratory Distress Syndrome

2021 ◽  
Vol 8 ◽  
Author(s):  
Rahul Y. Mahida ◽  
Aaron Scott ◽  
Dhruv Parekh ◽  
Sebastian T. Lugg ◽  
Kylie B. R. Belchamber ◽  
...  
Keyword(s):  
Gene Expression ◽  
Acute Respiratory Distress Syndrome ◽  
Respiratory Distress Syndrome ◽  
Respiratory Distress ◽  
Alveolar Macrophage ◽  
Distress Syndrome ◽  
Lung Resection ◽  
Macrophage Dysfunction

Background: Impaired alveolar macrophage (AM) efferocytosis may contribute to acute respiratory distress syndrome (ARDS) pathogenesis; however, studies are limited by the difficulty in obtaining primary AMs from patients with ARDS. Our objective was to determine whether an in vitro model of ARDS can recapitulate the same AM functional defect observed in vivo and be used to further investigate pathophysiological mechanisms.Methods: AMs were isolated from the lung tissue of patients undergoing lobectomy and then treated with pooled bronchoalveolar lavage (BAL) fluid previously collected from patients with ARDS. AM phenotype and effector functions (efferocytosis and phagocytosis) were assessed by flow cytometry. Rac1 gene expression was assessed using quantitative real-time PCR.Results: ARDS BAL treatment of AMs decreased efferocytosis (p = 0.0006) and Rac1 gene expression (p = 0.016); however, bacterial phagocytosis was preserved. Expression of AM efferocytosis receptors MerTK (p = 0.015) and CD206 (p = 0.006) increased, whereas expression of the antiefferocytosis receptor SIRPα decreased following ARDS BAL treatment (p = 0.036). Rho-associated kinase (ROCK) inhibition partially restored AM efferocytosis in an in vitro model of ARDS (p = 0.009).Conclusions: Treatment of lung resection tissue AMs with ARDS BAL fluid induces impairment in efferocytosis similar to that observed in patients with ARDS. However, AM phagocytosis is preserved following ARDS BAL treatment. This specific impairment in AM efferocytosis can be partially restored by inhibition of ROCK. This in vitro model of ARDS is a useful tool to investigate the mechanisms by which the inflammatory alveolar microenvironment of ARDS induces AM dysfunction.

scholarly journals MiR-124-3p helps to protect against acute respiratory distress syndrome by targeting p65

2020 ◽  
Vol 40 (5) ◽  
Author(s):  
Yufeng Liang ◽  
Junjie Xie ◽  
Di Che ◽  
Chunmin Zhang ◽  
Yongmin Lin ◽  
...  
Keyword(s):  
Acute Respiratory Distress Syndrome ◽  
Respiratory Distress Syndrome ◽  
Respiratory Distress ◽  
Cell Apoptosis ◽  
Distress Syndrome ◽  
Direct Interaction ◽  
Pulmonary Injury ◽  
Nr8383 Cells

Abstract Background: Acute respiratory distress syndrome (ARDS) is a severe form of acute lung injury that has a high mortality rate and leads to substantial healthcare costs. MicroRNA-124-3p (miR-124-3p) helps to suppress inflammation during a pulmonary injury. However, its mechanism of action is largely unknown, and its role in ARDS remains to be determined. Methods: Mice and NR8383 cells were exposed to lipopolysaccharides (LPS) to induce ARDS, and their miR-124-3p levels were determined. After a miRNA agomir was administrated to the mice, their pulmonary injuries were evaluated by H&E staining and assays for peripheral inflammatory cytokine levels. The direct interaction between miR-124-3p and p65 was predicted, and then confirmed by a luciferase activity assay. The role played by miRNA-124-3p in regulating p65 expression was further examined by transfection with its agomir, and its role in cell apoptosis was investigated by observing the effects of miRNA overexpression in vitro and in vivo. Results: After exposure to LPS, there was a consistent decrease in miR-124-3p expression in the lungs of mice and in NR8383 cells. After treatment with the miR-124-3p agomir, the degrees of pulmonary injury (e.g. alveolar hemorrhage and interstitial edema), and the increases in IL-1β, IL-6, and TNF-α levels induced by LPS were significantly attenuated. Overexpression of miR-124-3p in NC8383 cells and lung tissues significantly suppressed LPS-induced p65 expression and cell apoptosis. Conclusions: These results suggest that miR-124-3p directly targeted p65, and thereby decreased the levels of inflammation and pulmonary injury in a mouse model of ARDS.

scholarly journals SARS-CoV-2 envelope protein causes acute respiratory distress syndrome (ARDS)-like pathological damages and constitutes an antiviral target

Cell Research ◽  
2021 ◽  
Author(s):  
Bingqing Xia ◽  
Xurui Shen ◽  
Yang He ◽  
Xiaoyan Pan ◽  
Feng-Liang Liu ◽  
...  
Keyword(s):  
Cell Death ◽  
Acute Respiratory Distress Syndrome ◽  
Respiratory Distress Syndrome ◽  
Respiratory Distress ◽  
Distress Syndrome ◽  
Dominant Negative ◽  
Dominant Negative Mutation ◽  
E Protein

AbstractCytokine storm and multi-organ failure are the main causes of SARS-CoV-2-related death. However, the origin of excessive damages caused by SARS-CoV-2 remains largely unknown. Here we show that the SARS-CoV-2 envelope (2-E) protein alone is able to cause acute respiratory distress syndrome (ARDS)-like damages in vitro and in vivo. 2-E proteins were found to form a type of pH-sensitive cation channels in bilayer lipid membranes. As observed in SARS-CoV-2-infected cells, heterologous expression of 2-E channels induced rapid cell death in various susceptible cell types and robust secretion of cytokines and chemokines in macrophages. Intravenous administration of purified 2-E protein into mice caused ARDS-like pathological damages in lung and spleen. A dominant negative mutation lowering 2-E channel activity attenuated cell death and SARS-CoV-2 production. Newly identified channel inhibitors exhibited potent anti-SARS-CoV-2 activity and excellent cell protective activity in vitro and these activities were positively correlated with inhibition of 2-E channel. Importantly, prophylactic and therapeutic administration of the channel inhibitor effectively reduced both the viral load and secretion of inflammation cytokines in lungs of SARS-CoV-2-infected transgenic mice expressing human angiotensin-converting enzyme 2 (hACE-2). Our study supports that 2-E is a promising drug target against SARS-CoV-2.

scholarly journals 3,5,4′-Tri-O-acetylresveratrol Attenuates Lipopolysaccharide-Induced Acute Respiratory Distress Syndrome via MAPK/SIRT1 Pathway

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Lijie Ma ◽  
Yilin Zhao ◽  
Ruixuan Wang ◽  
Tingting Chen ◽  
Wangping Li ◽  
...  
Keyword(s):  
Acute Respiratory Distress Syndrome ◽  
Respiratory Distress Syndrome ◽  
Respiratory Distress ◽  
Distress Syndrome ◽  
Dry Weight ◽  
Lavage Fluid ◽  
Histological Changes ◽  
Lung Injuries

The aim of the present research was to investigate the protecting effects of 3,5,4′-tri-O-acetylresveratrol (AC-Rsv) on LPS-induced acute respiratory distress syndrome (ARDS). Lung injuries have been evaluated by histological examination, wet-to-dry weight ratios, and cell count and protein content in bronchoalveolar lavage fluid. Inflammation was assessed by MPO activities and cytokine secretion in lungs and cells. The results showed that AC-Rsv significantly reduced the mortality of mice stimulated with LPS. Pretreatment of AC-Rsv attenuated LPS-induced histological changes, alleviated pulmonary edema, reduced blood vascular leakage, and inhibited the MPO activities in lungs. What was more, AC-Rsv and Rsv treatment reduced the secretion of TNF-α, IL-6, and IL-1βin lungs and NR8383 cells, respectively. Further exploration revealed that AC-Rsv and Rsv treatment relieved LPS-induced inhibition on SIRT1 expression and restrained the activation effects of LPS on MAPKs and NF-κB activation both in vitro and in vivo. More importantly, in vivo results have also demonstrated that the protecting effects of Rsv on LPS-induced inflammation would be neutralized when SIRT1 was in-hibited by EX527. Taken together, these results indicated that AC-Rsv protected lung tissue against LPS-induced ARDS by attenuating inflammation via p38 MAPK/SIRT1 pathway.

scholarly journals Glutamine Therapy Reduces Inflammation and Extracellular Trap Release in Experimental Acute Respiratory Distress Syndrome of Pulmonary Origin

Nutrients ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 831 ◽  
Author(s):  
Gisele Pena de Oliveira ◽  
Jamil Zola Kitoko ◽  
Phillipe de Souza Lima-Gomes ◽  
Natália Cadaxo Rochael ◽  
Carla Cristina de Araújo ◽  
...  
Keyword(s):  
Acute Respiratory Distress Syndrome ◽  
Respiratory Distress Syndrome ◽  
Respiratory Distress ◽  
Lung Inflammation ◽  
Distress Syndrome ◽  
Lavage Fluid ◽  
Interleukin 10 ◽  
Myeloperoxidase Activity

The innate immune response plays an important role in the pathophysiology of acute respiratory distress syndrome (ARDS). Glutamine (Gln) decreases lung inflammation in experimental ARDS, but its impact on the formation of extracellular traps (ETs) in the lung is unknown. In a mouse model of endotoxin-induced pulmonary ARDS, the effects of Gln treatment on leukocyte counts and ET content in bronchoalveolar lavage fluid (BALF), inflammatory profile in lung tissue, and lung morphofunction were evaluated in vivo. Furthermore, ET formation, reactive oxygen species (ROS) production, glutathione peroxidase (GPx), and glutathione reductase (GR) activities were tested in vitro. Our in vivo results demonstrated that Gln treatment reduced ET release (as indicated by cell-free-DNA content and myeloperoxidase activity), decreased lung inflammation (reductions in interferon-γ and increases in interleukin-10 levels), and improved lung morpho-function (decreased static lung elastance and alveolar collapse) in comparison with ARDS animals treated with saline. Moreover, Gln reduced ET and ROS formation in BALF cells stimulated with lipopolysaccharide in vitro, but it did not alter GPx or GR activity. In this model of endotoxin-induced pulmonary ARDS, treatment with Gln reduced pulmonary functional and morphological impairment, inflammation, and ET release in the lung.

scholarly journals SARS-CoV-2 envelope protein causes acute respiratory distress syndrome (ARDS)-like pathological damage and constitutes an antiviral target

2020 ◽  
Author(s):  
Bingqing Xia ◽  
Xurui Shen ◽  
Yang He ◽  
Xiaoyan Pan ◽  
Yi Wang ◽  
...  
Keyword(s):  
Acute Respiratory Distress Syndrome ◽  
Respiratory Distress Syndrome ◽  
Respiratory Distress ◽  
Distress Syndrome ◽  
Cell Protection ◽  
Membrane Rupture ◽  
E Protein ◽  
Channel Inhibition

SummaryCytokine storm and multi-organ failure are the main causes of SARS-CoV-2-related death. However, the origin of the virus’ excessively damaging abilities remains unknown. Here we show that the SARS-CoV-2 envelope (2-E) protein alone is sufficient to cause acute respiratory distress syndrome (ARDS)-like damage in vitro and in vivo. Overexpression of 2-E protein induced rapid pyroptosis-like cell death in various susceptible cells and robust secretion of cytokines and chemokines in macrophages. Intravenous administration of purified 2-E protein into mice caused ARDS-like pathological damage in lung and spleen. Overexpressed 2-E protein formed cation channels in host cell membranes, eventually leading to membrane rupture. Newly identified channel inhibitors exhibited potent anti-SARS-CoV-2 activity and excellent protective effects against the 2-E-induced damage both in vitro and in vivo. Importantly, their channel inhibition, cell protection and antiviral activities were positively correlated with each other, supporting 2-E is a promising drug target against SARS-CoV-2.

scholarly journals Acute Respiratory Distress Syndrome is associated with impaired alveolar macrophage efferocytosis

2021 ◽  
Author(s):  
Rahul Y Mahida ◽  
Aaron Scott ◽  
Dhruv Parekh ◽  
Sebastian T Lugg ◽  
Rowan Hardy ◽  
...  
Keyword(s):  
Gene Expression ◽  
Acute Respiratory Distress Syndrome ◽  
Respiratory Distress Syndrome ◽  
Respiratory Distress ◽  
Alveolar Macrophage ◽  
Clinical Outcomes ◽  
Alveolar Macrophages ◽  
Distress Syndrome ◽  
Receptor Expression ◽  
Neutrophil Apoptosis

Background: Alveolar macrophage dysfunction may contribute to Acute Respiratory Distress Syndrome (ARDS) pathogenesis, however this has been little studied. Objective: To investigate the pathophysiological link between alveolar macrophage efferocytosis, alveolar neutrophil apoptosis and clinical outcomes in ARDS patients, and to determine whether efferocytosis can be restored. Methods: Ventilated sepsis patients with or without ARDS underwent broncho-alveolar lavage. Apoptosis of alveolar neutrophils was assessed using flow cytometry. Alveolar macrophages were isolated and used in flow cytometric efferocytosis assays with labelled apoptotic neutrophils. Alveolar macrophages were also isolated from the lung tissue of lobectomy patients, then treated with pooled ARDS BAL fluid prior to functional assessment. Rac1 gene expression was assessed using RT-qPCR. Results: Patients with sepsis-related ARDS have decreased alveolar macrophage efferocytosis and increased alveolar neutrophil apoptosis compared to control ventilated sepsis patients. Across all ventilated sepsis patients, alveolar macrophage efferocytosis correlated negatively with alveolar cytokines (IL-8, IL-1ra), duration of ventilation and mortality. ARDS BAL treatment of alveolar macrophages decreased efferocytosis and Rac1 gene expression, however bacterial phagocytosis was preserved. Unexpectedly, alveolar macrophage efferocytosis receptor expression (MerTK, CD206) decreased and expression of the anti-efferocytosis receptor SIRPα increased following ARDS BAL treatment. Rho-associated kinase inhibition partially restored alveolar macrophage efferocytosis in an in vitro model of ARDS. Conclusions: Patients with sepsis-related ARDS have impaired alveolar macrophage efferocytosis, resulting in persistent inflammation from secondary neutrophil necrosis. This potentially has a negative effect on clinical outcomes, including mortality. Strategies to upregulate AM efferocytosis may be of value for attenuating inflammation in ARDS.

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