scholarly journals Oxypaeoniflorin Prevents Acute Lung Injury Induced by Lipopolysaccharide through the PTEN/AKT Pathway in a Sirt1-Dependent Manner

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Fan Guohua ◽  
Zhu Tieyuan ◽  
Wang Rui ◽  
Xiong Juan
Keyword(s):  
Oxidative Stress ◽  
Acute Lung Injury ◽  
Epithelial Cells ◽  
Lung Injury ◽  
Inflammatory Response ◽  
Alveolar Epithelial Cells ◽  
Dependent Manner ◽  
Alveolar Epithelial ◽  
And Oxidative Stress

Acute lung injury (ALI) is featured by pulmonary edema, alveolar barrier injury, inflammatory response, and oxidative stress. The activation of Sirt1 could relieve lipopolysaccharide- (LPS-) induced murine ALI by maintaining pulmonary epithelial barrier function. Oxypaeoniflorin (Oxy) serves as a major component of Paeonia lactiflora Pall., exerting cardioprotection by activating Sirt1. However, the role of Oxy in ALI induced by LPS remains unclear. The aim of the present study is to illustrate the modulatory effects and molecular mechanisms by which Oxy operates in ALI induced by LPS. The intraperitoneal injection of LPS was performed to establish the murine ALI model while LPS-treated alveolar epithelial cells were used to mimic the in vitro ALI model. Levels of lung injury, oxidative stress, and inflammatory response were detected to observe the potential effects of Oxy on ALI. Oxy treatment mitigated lung edema, inflammatory response, and oxidative stress in mouse response to LPS, apart from improving 7-day survival. Meanwhile, Oxy also increased the expression and activity of Sirt1. Intriguingly, Sirt1 deficiency or inhibition counteracted the protective effects of Oxy treatment in LPS-treated mice or LPS-treated alveolar epithelial cells by regulating the PTEN/AKT signaling pathway. These results demonstrated that Oxy could combat ALI in vivo and in vitro through inhibiting inflammatory response and oxidative stress in a Sirt1-dependent manner. Oxy owns the potential to be a promising candidate against ALI.

Reticulocalbin 3 deficiency in alveolar epithelium attenuated LPS-induced ALI via NF-κB signaling

2021 ◽  
Vol 320 (4) ◽  
pp. L627-L639
Author(s):  
Xiaoqian Shi ◽  
Xiaojie An ◽  
Liu Yang ◽  
Zhipeng Wu ◽  
Danni Zan ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Lung Injury ◽  
Inflammatory Response ◽  
Secretory Pathway ◽  
Alveolar Epithelium ◽  
Repair Process ◽  
Alveolar Epithelial Cells ◽  
Alveolar Epithelial

Acute respiratory distress syndrome (ARDS) is characterized by acute lung injury (ALI) secondary to an excessive alveolar inflammatory response. Reticulocalbin 3 (Rcn3) is an endoplasmic reticulum (ER) lumen protein in the secretory pathway. We previously reported the indispensable role of Rcn3 in type II alveolar epithelial cells (AECIIs) during lung development and the lung injury repair process. In the present study, we further observed a marked induction of Rcn3 in the alveolar epithelium during LPS-induced ALI. In vitro alveolar epithelial (MLE-12) cells consistently exhibited a significant induction of Rcn3 accompanied with NF-κB activation in response to LPS exposure. We examined the role of Rcn3 in the alveolar inflammatory response by using mice with a selective deletion of Rcn3 in alveolar epithelial cells upon doxycycline administration. The Rcn3 deficiency significantly blunted the ALI and alveolar inflammation induced by intratracheal LPS instillation but not that induced by an intraperitoneal LPS injection (secondary insult); the alleviated ALI was accompanied by decreases in NF-κB activation and NLRP3 levels but not in GRP78 and cleaved caspase-3 levels. The studies conducted in MLE-12 cells consistently showed that Rcn3 knockdown blunted the activations of NF-κB signaling and NLRP3-dependent inflammasome upon LPS exposure. Collectively, these findings suggest a novel role for Rcn3 in regulating the alveolar inflammatory response to pulmonary infection via the NF-κB/NLRP3/inflammasome axis and shed additional light on the mechanism of ARDS/ALI.

scholarly journals Alarmin S100A8 Activates Alveolar Epithelial Cells in the Context of Acute Lung Injury in a TLR4-Dependent Manner

2017 ◽  
Vol 8 ◽  
Author(s):  
Deblina Chakraborty ◽  
Stefanie Zenker ◽  
Jan Rossaint ◽  
Anna Hölscher ◽  
Michele Pohlen ◽  
...  
Keyword(s):  
Acute Lung Injury ◽  
Epithelial Cells ◽  
Lung Injury ◽  
Alveolar Epithelial Cells ◽  
Dependent Manner ◽  
Alveolar Epithelial

scholarly journals Exosomes Derived From Alveolar Epithelial Cells Promote Alveolar Macrophage Activation Mediated by miR-92a-3p in Sepsis-Induced Acute Lung Injury

2021 ◽  
Vol 11 ◽  
Author(s):  
Fen Liu ◽  
Wei Peng ◽  
Jiaquan Chen ◽  
Zeyao Xu ◽  
Rong Jiang ◽  
...  
Keyword(s):  
Acute Lung Injury ◽  
Epithelial Cells ◽  
Lung Injury ◽  
Pulmonary Inflammation ◽  
Cecal Ligation ◽  
Alveolar Epithelial Cells ◽  
Luciferase Reporter ◽  
Alveolar Epithelial

Acute lung injury (ALI) induced by sepsis is characterized by disruption of the epithelial barrier and activation of alveolar macrophages (AMs), which leads to uncontrolled pulmonary inflammation. However, effective treatments for ALI are unavailable. The exact mechanism by which the initial mediator of alveolar epithelial cells (AECs) induces inflammation remains elusive. Here we investigated the roles of AEC-derived exosomes in AM activation and sepsis-induced ALI in vivo and in vitro. Cecal ligation and puncture (CLP) was utilized to establish septic lung injury model in rats. The effect of exosomal inhibition by intratracheal GW4869 administration on lung injury was investigated. To assess the effects of AEC-derived exosomes on ALI, we treated the rat alveolar epithelial cell line RLE-6TN with LPS to induce cell damage. Exosomes from conditioned medium of LPS-treated AECs (LPS-Exos) were isolated by ultracentrifugation. The miRNAs in LPS-Exos were screened by miRNA expression profile analysis. The effects of miR-92a-3p on the function of AMs were studied. We found that intratracheal GW4869 administration ameliorated lung injury following CLP-induced ALI. LPS-Exos were taken up by AMs and activated these cells. Consistently, administration of LPS-Exos in rats significantly aggravated pulmonary inflammation and alveolar permeability. Moreover, miR-92a-3p was enriched in LPS-Exos and could be delivered to AMs. Inhibition of miR-92a-3p in AECs diminished the proinflammatory effects of LPS-Exos in vivo and in vitro. Mechanistically, miR-92a-3p activates AMs along with pulmonary inflammation. This process results in activation of the NF-κB pathway and downregulation of PTEN expression, which was confirmed by a luciferase reporter assay. In conclusion, AEC-derived exosomes activate AMs and induce pulmonary inflammation mediated by miR-92a-3p in ALI. The present findings revealed a previously unidentified role of exosomal miR-92a-3p in mediating the crosstalk between injured AEC and AMs. miR-92a-3p in AEC exosomes might represent a novel diagnostic biomarker for ALI, which may lead to a new therapeutic approach.

In vivo mitogenic action of HGF on lung epithelial cells: pulmotrophic role in lung regeneration

1996 ◽  
Vol 270 (6) ◽  
pp. L1031-L1039 ◽  
Author(s):  
H. Ohmichi ◽  
K. Matsumoto ◽  
T. Nakamura
Keyword(s):  
Acute Lung Injury ◽  
Epithelial Cells ◽  
Lung Injury ◽  
Dna Synthesis ◽  
Airway Epithelial Cells ◽  
Alveolar Epithelial Cells ◽  
Alveolar Epithelial ◽  
Lung Regeneration

Hepatocyte growth factor (HGF) has mitogenic, morphogenic, and motogenic activities on epithelial cells and plays important roles in regeneration of the liver and the kidney. We previously found that the expression of HGF gene is rapidly induced in the lung after acute lung injury in experimental animals and that HGF levels are elevated in blood of patients with lung diseases. To search for a possible pulmotrophic function of HGF in lung regeneration, we examined the mitogenic activity of HGF on tracheal epithelial cells in vitro and evaluated the efficacy of HGF-administration on lung regeneration after acute lung injury in mice. HGF markedly stimulated proliferation and DNA synthesis of rat tracheal epithelial cells in primary culture in a dose-dependent manner. The intravenous injection of human recombinant HGF (10 micrograms.mouse-1.day-1) into mice with acute lung injury induced by the intratracheal infusion of 10 mM HCI stimulated DNA synthesis of airway epithelial cells to levels threefold higher than those in mice with no HGF-injections, but it did not stimulate DNA synthesis of alveolar epithelial cells. However, HGF injection at higher dose (100 micrograms.mouse-1.day-1) stimulated DNA synthesis of alveolar epithelial cells in vivo. These results indicate that HGF is a potent mitogen for airway epithelial cells and alveolar epithelial cells in vivo as well as in vitro. HGF may act as pulmotrophic factor responsible for airway and alveolar regeneration during lung regeneration after acute lung injury.

scholarly journals Negative Effects of SIGIRR on TRAF6 Ubiquitination in Acute Lung Injury In Vitro

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Feng Tian ◽  
Qiang Lu ◽  
Jie Lei ◽  
Yunfeng Ni ◽  
Nianlin Xie ◽  
...  
Keyword(s):  
Immune Response ◽  
Acute Lung Injury ◽  
Epithelial Cells ◽  
Lung Injury ◽  
Alveolar Macrophage ◽  
Signaling Pathway ◽  
Alveolar Epithelial Cells ◽  
Alveolar Epithelial ◽  
Macrophage Cells

In this study, the effects of single immunoglobin IL-1 receptor-related protein (SIGIRR) on tumor necrosis factor- (TNF-) receptor-associated factor 6 (TRAF6) ubiquitination in acute lung injury (ALI) were evaluated in both alveolar epithelial cells and alveolar macrophage cells in vitro. Our results found that SIGIRR negatively regulated TRAF6 ubiquitination and such SIGIRR inhibition could enhance the TRAF6 expression in both alveolar epithelial cells (AECs) and alveolar macrophage cells (AMCs). SIGIRR knockdown may increase NF-κB activity via TRAF6 regulation by the classical but not the nonclassical NF-κB signaling pathway. Such modulation between TRAF6 and SIGIRR could affect cytokine secretion and exacerbate the immune response; the IL-8, NFKB1, and NFKBIA mRNA levels were reduced after SIGIRR overexpression. The current study reveals the molecular mechanisms of the negative regulatory roles of SIGIRR on the innate immune response related to the LPS/TLR-4 signaling pathway and provides evidence for strategies to clinically treat inflammatory diseases.

H2O2 inhibits alveolar epithelial wound repair in vitro by induction of apoptosis

2004 ◽  
Vol 287 (2) ◽  
pp. L448-L453 ◽  
Author(s):  
Thomas Geiser ◽  
Masanobu Ishigaki ◽  
Coretta van Leer ◽  
Michael A. Matthay ◽  
V. Courtney Broaddus
Keyword(s):  
Acute Lung Injury ◽  
Epithelial Cells ◽  
Lung Injury ◽  
Cell Viability ◽  
Wound Repair ◽  
Wound Edge ◽  
Alveolar Epithelial ◽  
Induction Of Apoptosis

Reactive oxygen species (ROS) are released into the alveolar space and contribute to alveolar epithelial damage in patients with acute lung injury. However, the role of ROS in alveolar repair is not known. We studied the effect of ROS in our in vitro wound healing model using either human A549 alveolar epithelial cells or primary distal lung epithelial cells. We found that H2O2 inhibited alveolar epithelial repair in a concentration-dependent manner. At similar concentrations, H2O2 also induced apoptosis, an effect seen particularly at the edge of the wound, leading us to hypothesize that apoptosis contributes to H2O2-induced inhibition of wound repair. To learn the role of apoptosis, we blocked caspases with the pan-caspase inhibitor N-benzyloxycarbonyl-Val-Ala-Asp (zVAD). In the presence of H2O2, zVAD inhibited apoptosis, particularly at the wound edge and, most importantly, maintained alveolar epithelial wound repair. In H2O2-exposed cells, zVAD also maintained cell viability as judged by improved cell spreading and/or migration at the wound edge and by a more normal mitochondrial potential difference compared with cells not treated with zVAD. In conclusion, H2O2 inhibits alveolar epithelial wound repair in large part by induction of apoptosis. Inhibition of apoptosis can maintain wound repair and cell viability in the face of ROS. Inhibiting apoptosis may be a promising new approach to improve repair of the alveolar epithelium in patients with acute lung injury.

scholarly journals Photobiomodulation prevents DNA fragmentation of alveolar epithelial cells and alters the mRNA levels of caspase 3 and Bcl-2 genes in acute lung injury

2018 ◽  
Vol 17 (7) ◽  
pp. 975-983 ◽  
Author(s):  
Luiz Philippe da Silva Sergio ◽  
Andrezza Maria Côrtes Thomé ◽  
Larissa Alexsandra da Silva Neto Trajano ◽  
Andre Luiz Mencalha ◽  
Adenilson de Souza da Fonseca ◽  
...  
Keyword(s):  
Acute Lung Injury ◽  
Epithelial Cells ◽  
Lung Injury ◽  
Dna Fragmentation ◽  
Caspase 3 ◽  
Alveolar Epithelial Cells ◽  
Mrna Levels ◽  
Alveolar Epithelial ◽  
Life Threatening ◽  
Pulmonary Permeability

Acute lung injury (ALI) is defined as hyperinflammation that could occur from sepsis and lead to pulmonary permeability and edema, making them life-threatening diseases.

Silica directly increases permeability of alveolar epithelial cells

1990 ◽  
Vol 68 (4) ◽  
pp. 1354-1359 ◽  
Author(s):  
R. K. Merchant ◽  
M. W. Peterson ◽  
G. W. Hunninghake
Keyword(s):  
Epithelial Cells ◽  
Cell Injury ◽  
Alveolar Epithelial Cell ◽  
Alveolar Epithelium ◽  
Alveolar Epithelial Cells ◽  
Dependent Manner ◽  
Alveolar Epithelial ◽  
Lactate Dehydrogenase Release ◽  
Capillary Membrane

Alveolar epithelial cell injury and increased alveolar-capillary membrane permeability are important features of acute silicosis. To determine whether silica particles contribute directly to this increased permeability, we measured paracellular permeability of rat alveolar epithelium after exposure to silica, in vitro, using markers of the extracellular space. Silica (Minusil) markedly increased permeability in a dose- and time-dependent manner. This was not the result of cytolytic injury, because lactate dehydrogenase release from monolayers exposed to silica was not increased. Pretreatment of the silica with serum, charged dextrans, or aluminum sulfate blocked the increase in permeability. Scanning electron microscopy demonstrated adherence of the silica to the surface of the alveolar epithelial cells. Thus silica can directly increase permeability of alveolar epithelium.

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