Geranylgeranyl diphosphate synthase deficiency hyperactivates macrophages and aggravates lipopolysaccharide-induced acute lung injury

Macrophage activation is a key contributing factor for excessive inflammatory responses of acute lung injury (ALI)/acute respiratory distress syndrome (ARDS). Geranylgeranyl diphosphate synthase (GGPPS) plays a key role in the development of inflammatory diseases. Our group previously showed that GGPPS in alveolar epithelium have deleterious effects on acute lung injury induced by LPS or mechanical ventilation. Herein, we examined the role of GGPPS in modulating macrophage activation in ALI/ARDS. We found significant increased GGPPS expression in alveolar macrophages in ARDS patients compared to healthy volunteers and in ALI mice induced by LPS. GGPPS-floxed control (GGPPSfl/fl) and myeloid-selective knockout (GGPPSfl/flLysMcre) mice were then generated. Interestingly, using a LPS-induced ALI mouse model, we showed that myeloid-specific GGPPS knockout significantly increased mortality, aggravated lung injury, and increased the accumulation of inflammatory cells, total protein, and inflammatory cytokines in BALF. In vitro, GGPPS deficiency up-regulated the production of LPS-induced IL-6, IL-1β, and TNF-α in alveolar macrophages, bone marrow-derived macrophages (BMDMs), and THP-1 cells. Mechanistically, GGPPS knockout increased phosphorylation and nuclear translocation of NF-κB p65 induced by LPS. In addition, GGPPS deficiency increased the level of GTP-Rac1, which was responsible for NF-κB activation. In conclusion, decreased expression of GGPPS in macrophages aggravates lung injury and inflammation in ARDS, at least partly by regulating Rac1-dependent NF-κB signaling. GGPPS in macrophages may represent a novel therapeutic target in ARDS.

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Mesenchymal Stem Cells Attenuate Acute Lung Injury in Mice Partly by Suppressing Alveolar Macrophage Activation in a PGE2-dependent Manner

10.21203/rs.3.rs-664786/v1 ◽

2021 ◽

Author(s):

Gaojian Wang ◽

Yaping Zhang ◽

Nianqiang Hu ◽

Qinxue Liu ◽

Fengjie Ma ◽

...

Keyword(s):

Acute Lung Injury ◽

Lung Injury ◽

Alveolar Macrophage ◽

Alveolar Macrophages ◽

Macrophage Activation ◽

Rna Seq ◽

Ep4 Receptor ◽

Pge2 Receptor ◽

Cox2 Inhibitor

Abstract Background: Mesenchymal stem cell have shown therapeutic effect on acute lung injury, MSC could be activated when added to inflammatory environment and in turn suppress inflammation, yet the mechanism is complex and not understood. Methods: To determine the effect of MSC on ALI and alveolar macrophage activation, MSCs were administered to ALI mice and co-cultured with activated MH-S cells (alveolar macrophage cell line). To find the genes critical for MSC’s immunosuppressive effects, rest and activated MSCs induced by inflammatory MH-S cells were harvested for RNA-seq. To prove that PGE2 participates in the immunosuppressive effects of MSC, COX2 inhibitor and PGE2 receptor antagonist were added to the co-culture system and administrated to ALI mice. Results: The intratracheal administration of MSCs attenuated ALI and suppressed alveolar macrophages activation in vivo, the activation of MH-S cells was also significantly reduced after co-culturing with MSCs in vitro. The RNA-seq data of rest and activated MSCs suggested that the Ptgs2 gene may play an important role in MSC exerting immunosuppressive effects. Correspondingly, we found that the COX2 protein and PGE2 released by activated MSCs were increased dramatically after co-culturing with MH-S. The use of COX2 inhibitor NS-398 restrained the secretion of PGE2 and reversed the suppressive effect on macrophages activation of MSCs in vitro. Furthermore, GW627368X, a selective antagonist of PGE2 receptor (EP4 receptor), also reversed the inhibitory effects of MSCs on alveolar macrophages and their protective effects on ALI mice.Conclusions: MSC attenuate ALI partly through suppressing alveolar macrophage activation via PGE2 binding to EP4 receptor.

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Ghrelin attenuates sepsis-induced acute lung injury by inhibiting the NF-κB, iNOS, and Akt signaling in alveolar macrophages

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.00253.2018 ◽

2019 ◽

Vol 317 (3) ◽

pp. L381-L391 ◽

Cited By ~ 4

Author(s):

Haichong Zheng ◽

Wenjie Liang ◽

Wanmei He ◽

Chunrong Huang ◽

Qingui Chen ◽

...

Keyword(s):

Acute Lung Injury ◽

Lung Injury ◽

Alveolar Macrophages ◽

Inflammatory Responses ◽

Pulmonary Inflammation ◽

Cecal Ligation ◽

Protective Role ◽

Akt Signaling ◽

Cytokines And Chemokines

Ghrelin has proven to be protective against sepsis-induced acute lung injury (ALI) via anti-inflammatory effects. However, its mechanisms remain poorly understood. Alveolar macrophages (AMs) play a key role in mediating inflammatory responses during sepsis-induced ALI by secretion of cytokines and chemokines. This study was undertaken to investigate whether ghrelin suppresses inflammatory effects of AMs and therefore may help to attenuate sepsis-induced ALI. A sepsis model in rats was achieved using cecal ligation and puncture. Ghrelin treatment markedly improved histopathological changes in the lungs and reduced pulmonary inflammation in septic rats. NF-κB translocation and p-Akt and inducible nitric oxide synthase (iNOS) activities in AMs from septic rats were suppressed by ghrelin. In vitro data indicated that ghrelin decreased the levels of LPS-induced IL-1β, TNF-α, and IL-6, NF-κB translocation, and iNOS and Akt activities of AMs. Furthermore, the NF-κB/iNOS pathway or Akt signaling was positively correlated with LPS-induced inflammatory production of AMs in vitro. In conclusion, ghrelin exerts a protective role against sepsis-induced ALI probably by reducing the production of inflammatory cytokines from AMs via inhibition of the NF-κB/iNOS pathway or Akt signaling.

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LncRNA HOTAIR Increases Inflammatory Responses by Activating NF-κB Pathway in LPS-Induced Acute Lung Injury

10.21203/rs.3.rs-49969/v1 ◽

2020 ◽

Author(s):

XiaoMei Huang ◽

ZeXun Mo ◽

YuJun Li ◽

Hua He ◽

KangWei Wang ◽

...

Keyword(s):

Acute Lung Injury ◽

Lung Injury ◽

Noncoding Rna ◽

Nuclear Translocation ◽

Inflammatory Responses ◽

A549 Cells ◽

Enzyme Linked Immunosorbent Assay ◽

Qrt Pcr ◽

Tnf Α ◽

Lncrna Hotair

Abstract Background Nuclear factor kappa-B (NF-κB) activation increased the expression of cytokines and further lead to lung injury was considered the main mechanism of acute lung injury (ALI). Here, we focus on exploring the potential regulatory mechanism between long noncoding RNA (LncRNA) HOX transcript antisense RNA (HOTAIR) and NF-κB on LPS-induced ALI. Methods A549 cells were then divided into 4 groups: HOTAIR group, NC group, si-HOTAIR group and si-NC group. These 4 groups were then treated with 1μg/mL lipopolysaccharides (LPS) or without LPS at 37°C for 24 h. The expression level of cytokines (tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-6) and LncRNA HOTAIR were evaluated by quantitative Real Time Polymerase Chain Reaction (qRT-PCR) and Enzyme-linked immunosorbent assay (ELISA). Western Blot analysis was adopted for evaluating the level of p-IκBα/IκBα and p-p65/p65. Nuclear translocation of p65 was observed by immunofluorescence staining. Results qRT-PCR and ELISA assay showed that the expression of cytokines (IL-1β, IL-6 and TNF-α) and inflammatory gene HOTAIR was remarkably increased with LPS treatment (p < 0.01). Over-expression of HOTAIR significantly increased the expression of cytokines (including IL-1β, IL-6 and TNF-α) and NF-κB pathway associated proteins (including p-IκBα/IκBα and p-p65/p65), while knockdown of HOTAIR had the opposite effect (p < 0.01). The immunofluorescence assay showed that the level of p65 in the nucleus was significantly higher in the HOTAIR group and significantly lowers in the si-HOTAIR group (p < 0.01). Conclusion HOTAIR may play a pro-inflammatory response through NF-κB pathway in LPS-induced ALI, which may provide a perspective for further understanding the pathogenic mechanism of ALI.

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A Subanesthetic Dose of Isoflurane during Postconditioning Ameliorates Zymosan-Induced Neutrophil Inflammation Lung Injury and Mortality in Mice

Mediators of Inflammation ◽

10.1155/2013/479628 ◽

2013 ◽

Vol 2013 ◽

pp. 1-14 ◽

Cited By ~ 5

Author(s):

Hui Wang ◽

Jing Fan ◽

Nan-lin Li ◽

Jun-tang Li ◽

Shi-fang Yuan ◽

...

Keyword(s):

Lung Injury ◽

Nuclear Translocation ◽

Inflammatory Responses ◽

Weight Ratio ◽

Polymorphonuclear Neutrophils ◽

Mouse Lung ◽

Endothelial Adhesion Molecule ◽

Primary Mouse

Anesthetic isoflurane (ISO) has immunomodulatory effects. In the present study, we investigated whether a subanesthetic dose of ISO (0.7%) protected against zymosan (ZY) induced inflammatory responses in the murine lung and isolated neutrophils. At 1 and 6 hrs after ZY administration intraperitoneally, ISO was inhaled for 1 hr, and 24 hrs later, lung inflammation and injury were assessed. We found that ISO improved the survival rate of mice and mitigated lung injury as characterized by the histopathology, wet-to-dry weight ratio, protein leakage, and lung function index. ISO significantly attenuated ZY-induced lung neutrophil recruitment and inflammation. This was suggested by the downregulation of (a) endothelial adhesion molecule expression and myeloperoxidase (MPO) activity in lung tissue and polymorphonuclear neutrophils (b) chemokines, and (c) proinflammatory cytokines in BALF. Furthermore, ZY-induced nuclear translocation and DNA-binding activity of NF-κB p65 were also reduced by ISO. ISO treatment inhibited iNOS expression and activity, as well as subsequent nitric oxide generation. Consistent with thesein vivoobservations,in vitrostudies confirmed that ISO blocked NF-κB and iNOS activation in primary mouse neutrophils challenged by ZY. These results provide evidence that 0.7% ISO ameliorates inflammatory responses in ZY-treated mouse lung and primary neutrophils.

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Osthole Protects against Acute Lung Injury by Suppressing NF-κB-Dependent Inflammation

Mediators of Inflammation ◽

10.1155/2018/4934592 ◽

2018 ◽

Vol 2018 ◽

pp. 1-12 ◽

Cited By ~ 9

Author(s):

Yiyi Jin ◽

Jianchang Qian ◽

Xin Ju ◽

Xiaodong Bao ◽

Li Li ◽

...

Keyword(s):

Acute Lung Injury ◽

Lung Injury ◽

Inflammatory Response ◽

Nuclear Translocation ◽

Tissue Injury ◽

Kidney Injury ◽

Peritoneal Macrophages ◽

Anti Inflammatory

Inflammation is a key factor in the pathogenesis of ALI. Therefore, suppression of inflammatory response could be a potential strategy to treat LPS-induced lung injury. Osthole, a natural coumarin extract, has been reported to protect against acute kidney injury through an anti-inflammatory mechanism, but its effect on ALI is poorly understood. In this study, we investigated whether osthole ameliorates inflammatory sepsis-related ALI. Results from in vitro studies indicated that osthole treatment inhibited the LPS-induced inflammatory response in mouse peritoneal macrophages through blocking the nuclear translocation of NF-κB. Consistently, the in vivo studies indicated that osthole significantly prolonged the survival of septic mice which was accompanied by inflammation suppression. In the ALI mouse model, osthole effectively inhibited the development of lung tissue injury, leukocytic recruitment, and cytokine productions, which was associated with inhibition of NF-κB nuclear translocation. These findings provide evidence that osthole was a potent inhibitor of NF-κB and inflammatory injury and suggest that it could be a promising anti-inflammatory agent for therapy of septic shock and acute lung injury.

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Biocompatible N-acetyl-nanoconstruct alleviates lipopolysaccharide-induced acute lung injury in vivo

Scientific Reports ◽

10.1038/s41598-021-01624-5 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Seongchan Kim ◽

Shin Young Kim ◽

Seung Joon Rho ◽

Seung Hoon Kim ◽

So Hyang Song ◽

...

Keyword(s):

Acute Lung Injury ◽

Lung Injury ◽

Inflammatory Responses ◽

Therapeutic Potential ◽

Intratracheal Instillation ◽

Sprague Dawley ◽

In Vivo Experiments ◽

Anti Inflammatory

AbstractOxidative stress plays important roles in inflammatory responses during acute lung injury (ALI). Recently, nanoconstruct (Nano)-based drug-delivery systems have shown promise in many models of inflammation. In this study, we evaluated the anti-inflammatory effects of N-acetylcysteine (NAC) loaded in a biocompatible Nano using a rat model of ALI. We synthesized a Nano with a good NAC-releasing capacity using porous silica Nano, which was used to produce Nano/NAC complexes. For in vivo experiments, Sprague–Dawley rats were intraperitoneally administered NAC or Nano/NAC 30 min after intratracheal instillation of lipopolysaccharide. After 6 h, bronchoalveolar lavage fluids and lung tissues were collected. The anti-oxidative effect of the Nano/NAC complex was confirmed by demonstrating reduced levels of reactive oxygen species after treatment with the Nano/NAC in vitro. In vivo experiments also showed that the Nano/NAC treatment may protect against LPS‐induced ALI thorough anti‐oxidative and anti‐inflammatory effects, which may be attributed to the inactivation of the NF‐κB and MAPK pathways. In addition, the effects of Nano/NAC treatment were shown to be superior to those of NAC alone. We suggest the therapeutic potential of Nano/NAC treatment as an anti‐inflammatory agent against ALI. Furthermore, our study can provide basic data for developing nanotechnology-based pharmacotherapeutics for ALI.

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Spiraea prunifolia var. simpliciflora Attenuates Oxidative Stress and Inflammatory Responses in a Murine Model of Lipopolysaccharide-Induced Acute Lung Injury and TNF-α-Stimulated NCI-H292 Cells

Antioxidants ◽

10.3390/antiox9030198 ◽

2020 ◽

Vol 9 (3) ◽

pp. 198 ◽

Cited By ~ 1

Author(s):

Ba-Wool Lee ◽

Ji-Hye Ha ◽

Han-Gyo Shin ◽

Seong-Hun Jeong ◽

Da-Bin Jeon ◽

...

Keyword(s):

Oxidative Stress ◽

Acute Lung Injury ◽

Lung Injury ◽

Nuclear Translocation ◽

Inflammatory Responses ◽

Therapeutic Potential ◽

Herbal Remedy ◽

Related Factor ◽

Nuclear Factor ◽

Tnf Α

Spiraea prunifolia var. simpliciflora (SP) is traditionally used as an herbal remedy to treat fever, malaria, and emesis. This study aimed to evaluate the anti-oxidative and anti-inflammatory properties of the methanol extract of SP leaves in tumor necrosis factor (TNF)-α-stimulated NCI-H292 cells and in a lipopolysaccharide (LPS)-induced acute lung injury (ALI) mouse model. SP decreased the number of inflammatory cells and the levels of TNF-α, interleukin (IL)-1β, and IL-6 in the bronchoalveolar lavage fluid, and inflammatory cell infiltration in the lung tissues of SP-treated mice. In addition, SP significantly suppressed the mRNA and protein levels of TNF-α, IL-1β, and IL-6 in TNF-α-stimulated NCI-H292 cells. SP significantly suppressed the phosphorylation of the mitogen-activated protein kinases (MAPKs) and p65-nuclear factor-kappa B (NF-κB) in LPS-induced ALI mice and TNF-α-stimulated NCI-H292 cells. SP treatment enhanced the nuclear translocation of nuclear factor erythroid 2-related factor (Nrf2) with upregulated antioxidant enzymes and suppressed reactive oxygen species (ROS)-mediated oxidative stress in the lung tissues of LPS-induced ALI model and TNF-α-stimulated NCI-H292 cells. Collectively, SP effectively inhibited airway inflammation and ROS-mediated oxidative stress, which was closely related to its ability to induce activation of Nrf2 and inhibit the phosphorylation of MAPKs and NF-κB. These findings suggest that SP has therapeutic potential for the treatment of ALI.

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Phagocytosis of microparticles by alveolar macrophages during acute lung injury requires MerTK

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.00058.2017 ◽

2018 ◽

Vol 314 (1) ◽

pp. L69-L82 ◽

Cited By ~ 12

Author(s):

Michael P. Mohning ◽

Stacey M. Thomas ◽

Lea Barthel ◽

Kara J. Mould ◽

Alexandria L. McCubbrey ◽

...

Keyword(s):

Acute Lung Injury ◽

Lung Injury ◽

Alveolar Macrophages ◽

Primary Objective ◽

Cytochalasin D ◽

Inflammatory Signaling ◽

Macrophage Population ◽

Bronchoalveolar Fluid

Microparticles are a newly recognized class of mediators in the pathophysiology of lung inflammation and injury, but little is known about the factors that regulate their accumulation and clearance. The primary objective of our study was to determine whether alveolar macrophages engulf microparticles and to elucidate the mechanisms by which this occurs. Alveolar microparticles were quantified in bronchoalveolar fluid of mice with lung injury induced by LPS and hydrochloric acid. Microparticle numbers were greatest at the peak of inflammation and declined as inflammation resolved. Isolated, fluorescently labeled particles were placed in culture with macrophages to evaluate ingestion in the presence of endocytosis inhibitors. Ingestion was blocked with cytochalasin D and wortmannin, consistent with a phagocytic process. In separate experiments, mice were treated intratracheally with labeled microparticles, and their uptake was assessed though microscopy and flow cytometry. Resident alveolar macrophages, not recruited macrophages, were the primary cell-ingesting microparticles in the alveolus during lung injury. In vitro, microparticles promoted inflammatory signaling in LPS primed epithelial cells, signifying the importance of microparticle clearance in resolving lung injury. Microparticles were found to have phosphatidylserine exposed on their surfaces. Accordingly, we measured expression of phosphatidylserine receptors on macrophages and found high expression of MerTK and Axl in the resident macrophage population. Endocytosis of microparticles was markedly reduced in MerTK-deficient macrophages in vitro and in vivo. In conclusion, microparticles are released during acute lung injury and peak in number at the height of inflammation. Resident alveolar macrophages efficiently clear these microparticles through MerTK-mediated phagocytosis.

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GM-CSF receptor expression and signaling is decreased in lungs of ethanol-fed rats

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.00150.2006 ◽

2006 ◽

Vol 291 (6) ◽

pp. L1150-L1158 ◽

Cited By ~ 35

Author(s):

Pratibha C. Joshi ◽

Lisa Applewhite ◽

Patrick O. Mitchell ◽

Khaled Fernainy ◽

Jesse Roman ◽

...

Keyword(s):

Acute Lung Injury ◽

Lung Injury ◽

Alveolar Epithelium ◽

Receptor Expression ◽

Chronic Ethanol ◽

Ethanol Ingestion ◽

Alveolar Epithelial ◽

Gm Csf ◽

Nuclear Binding

Alcohol abuse dramatically increases the risk of acute lung injury. In an experimental rat model of ethanol-mediated susceptibility to lung injury, recombinant granulocyte/macrophage colony-stimulating factor (GM-CSF) restored alveolar epithelial barrier function both in vitro and in vivo, even during acute endotoxemia. These findings suggested that the alveolar epithelium, which secretes GM-CSF into the airway where it is required for alveolar macrophage maturation, likewise responds to GM-CSF priming in a receptor-mediated manner. In this study we determined that both the GM-CSF receptor α- and β-subunits (GM-CSFRα and GM-CSFRβ) are expressed throughout the rat airway epithelium and that this expression was significantly decreased in the alveolar epithelium following chronic ethanol ingestion (6 wk). In parallel, PU.1, the master transcription factor for GM-CSF signaling in hematopoietic cells, is also expressed in alveolar epithelial cells, and ethanol ingestion likewise decreased PU.1 protein expression and nuclear binding in the alveolar epithelium. Finally, GM-CSF signaling as reflected by PU.1 expression and nuclear binding was restored with recombinant GM-CSF treatment in vitro. We conclude that chronic ethanol ingestion decreases GM-CSF receptor expression and signaling in the lung epithelium. Consequently, we speculate that dampening of GM-CSF stimulation of the alveolar epithelium is responsible at least in part for the diverse functional defects that characterize the alcoholic lung and could be a therapeutic target in acute lung injury.

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Tanreqing Inhibits LPS-Induced Acute Lung Injury In Vivo and In Vitro Through Downregulating STING Signaling Pathway

Frontiers in Pharmacology ◽

10.3389/fphar.2021.746964 ◽

2021 ◽

Vol 12 ◽

Author(s):

Yu-Qiong He ◽

Can-Can Zhou ◽

Jiu-Ling Deng ◽

Liang Wang ◽

Wan-Sheng Chen

Keyword(s):

Oxidative Stress ◽

Acute Lung Injury ◽

Lung Injury ◽

Signaling Pathway ◽

Inflammatory Responses ◽

Lung Edema ◽

Protective Effects ◽

And Oxidative Stress

Acute lung injury (ALI) is a common life-threatening lung disease, which is mostly associated with severe inflammatory responses and oxidative stress. Tanreqing injection (TRQ), a Chinese patent medicine, is clinically used for respiratory-related diseases. However, the effects and action mechanism of TRQ on ALI are still unclear. Recently, STING as a cytoplasmic DNA sensor has been found to be related to the progress of ALI. Here, we showed that TRQ significantly inhibited LPS-induced lung histological change, lung edema, and inflammatory cell infiltration. Moreover, TRQ markedly reduced inflammatory mediators release (TNF-α, IL-6, IL-1β, and IFN-β). Furthermore, TRQ also alleviated oxidative stress, manifested by increased SOD and GSH activities and decreased 4-HNE, MDA, LDH, and ROS activities. In addition, we further found that TRQ significantly prevented cGAS, STING, P-TBK, P-P65, P-IRF3, and P-IκBα expression in ALI mice. And we also confirmed that TRQ could inhibit mtDNA release and suppress signaling pathway mediated by STING in vitro. Importantly, the addition of STING agonist DMXAA dramatically abolished the protective effects of TRQ. Taken together, this study indicated that TRQ alleviated LPS-induced ALI and inhibited inflammatory responses and oxidative stress through STING signaling pathway.

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