Nitrite Alters Alveolar Macrophage Activation In The Inflammatory Response To Acute Lung Injury

Author(s):  
LING WANG ◽  
Mark T. Gladwin
2021 ◽  
Author(s):  
Gaojian Wang ◽  
Yaping Zhang ◽  
Nianqiang Hu ◽  
Qinxue Liu ◽  
Fengjie Ma ◽  
...  

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.


The Lancet ◽  
1988 ◽  
Vol 332 (8616) ◽  
pp. 872-874 ◽  
Author(s):  
C.J. Clark ◽  
W.H. Reid ◽  
A.J. Pollock ◽  
D. Campbell ◽  
C. Gemmell

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Qingsong Sun ◽  
Man Luo ◽  
Zhiwei Gao ◽  
Xiang Han ◽  
Weiqin Wu ◽  
...  

Abstract Background Acute lung injury (ALI) is a pulmonary disorder that leads to acute respiration failure and thereby results in a high mortality worldwide. Increasing studies have indicated that toll-like receptor 4 (TLR4) is a promoter in ALI, and we aimed to explore the underlying upstream mechanism of TLR4 in ALI. Methods We used lipopolysaccharide (LPS) to induce an acute inflammatory response in vitro model and a murine mouse model. A wide range of experiments including reverse transcription quantitative polymerase chain reaction, western blot, enzyme linked immunosorbent assay, flow cytometry, hematoxylin–eosin staining, RNA immunoprecipitation, luciferase activity and caspase-3 activity detection assays were conducted to figure out the expression status, specific role and potential upstream mechanism of TLR4 in ALI. Result TLR4 expression was upregulated in ALI mice and LPS-treated primary bronchial/tracheal epithelial cells. Moreover, miR-26a-5p was confirmed to target TLR4 according to results of luciferase reporter assay. In addition, miR-26a-5p overexpression decreased the contents of proinflammatory factors and inhibited cell apoptosis, while upregulation of TLR4 reversed these effects of miR-26a-5p mimics, implying that miR-26a-5p alleviated ALI by regulating TLR4. Afterwards, OPA interacting protein 5 antisense RNA 1 (OIP5-AS1) was identified to bind with miR-26a-5p. Functionally, OIP5-AS1 upregulation promoted the inflammation and miR-26a-5p overexpression counteracted the influence of OIP5-AS1 upregulation on cell inflammatory response and apoptosis. Conclusion OIP5-AS1 promotes ALI by regulating the miR-26a-5p/TLR4 axis in ALI mice and LPS-treated cells, which indicates a promising insight into diagnostics and therapeutics in ALI.


2019 ◽  
Vol 11 (16) ◽  
pp. 2081-2094 ◽  
Author(s):  
Tingting Guo ◽  
Zhenzhong Su ◽  
Qi Wang ◽  
Wei Hou ◽  
Junyao Li ◽  
...  

Aim: Thus far, the anti-inflammatory effect of vanillin in acute lung injury (ALI) has not been studied. This study aimed to investigate the effect of vanillin in lipopolysaccharide (LPS)-induced ALI. Results & methodology: Our study detected the anti-inflammatory effects of vanillin by ELISA and western blot, respectively. Pretreatment of mice with vanillin significantly attenuated LPS-stimulated lung histopathological changes, myeloperoxidase activity and expression levels of proinflammatory cytokines by inhibiting the phosphorylation activities of ERK1/2, p38, AKT and NF-κB p65. In addition, vanillin inhibited LPS-induced TNF-α and IL-6 expression in RAW264.7 cells via ERK1/2, p38 and NF-κB signaling. Conclusion: Vanillin can inhibit macrophage activation and lung inflammation, which suggests new insights for clinical treatment of ALI.


2020 ◽  
Author(s):  
Hongxia Mei ◽  
Ying Tao ◽  
Tianhao Zhang ◽  
Feng Qi

Abstract Background: Acute lung injury (ALI) and/or acute respiratory distress syndrome (ARDS) are critical life-threatening syndromes characterized by the infiltration of a large number of neutrophils that lead to an excessive inflammatory response. Emodin (Emo) is a naturally occurring anthraquinone derivative and an active ingredient of Chinese medicine. It is believed to have anti-inflammatory effects. In this study, we examined the impact of Emo on the pulmonary inflammatory response and the neutrophil function in a rat model of lipopolysaccharide (LPS)-induced ALI.Results: Treatment with Emo protected rat against LPS-induced ALI. Compared to untreated rat, Emo-treated rat exhibited significantly ameliorated lung pathological changes and decreased tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β). However, Emo has no protective effect on the rat model of acute lung injury with neutrophil deficiency. In addition, treatment with Emo enhanced the bactericidal capacity of LPS-induced neutrophils via the up-regulation of the ability of neutrophils to phagocytize bacteria and generate neutrophil extracellular traps (NETs). Emo also downregulated the neutrophil respiratory burst and the expression of reactive oxygen species (ROS) in LPS-stimulated neutrophils, alleviating the damage of neutrophils to surrounding tissues. Finally, Emo can accelerate the resolution of inflammation by promoting apoptosis of neutrophils. Conclusion: Our results provide the evidence that Emo could ameliorates LPS-induced ALI via its anti-inflammatory action by modulating the function of neutrophils. Emo may be a promising preventive and therapeutic agent in the treatment of ALI.


2021 ◽  
Author(s):  
Liang Qiao ◽  
Rongxia Li ◽  
Shangang Hu ◽  
Yu Liu ◽  
Hongqiang Liu ◽  
...  

Abstract Objective Previously, the protective effect of microRNA (miR)-145-5p has been discovered in acute lung injury (ALI). Thus, this study attempts to further discuss the mechanism of miR-145-5p in ALI through the downstream E26 transformation-specific proto-oncogene 2 (ETS2)/transforming growth factor β1 (TGF-β1)/Smad pathway. Methods A lipopolysaccharide (LPS)-induced rat ALI model was established. Recombinant adenovirus miR-145-5p and/or ETS2 overexpression plasmid was administrated into rats. Afterwards, pathological damage in the lung tissue, wet/dry (W/D) ratio, apoptosis and contents of serum inflammatory factors were observed. miR-145-5p, ETS2, TGF-β1, Smad2/3, phosphorylated Smad2/3 levels were measured in rats. Results miR-145-5p was down-regulated, ETS2 was up-regulated and TGF-β1/Smad pathway was activated in LPS-suffered rats. Overexpression of miR-145-5p inactivated the TGF-β1/Smad pathway and attenuated ALI, as reflected by relived pathological damage, and decreased W/D ratio, apoptosis and inflammatory response. Oppositely, loss of miR-145-5p or enhancement of ETS2 worsened ALI and activated the TGF-β1/Smad pathway. Moreover, elevation of ETS2 decreased miR-145-5p-mediated protection against ALI. Conclusion Evidently, miR-145-5p negatively regulates ETS2 expression and inactivates TGF-β1/Smad pathway to ameliorate ALI in rats.


2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Jinfang Deng ◽  
Zhenpeng He ◽  
Xiuru Li ◽  
Wei Chen ◽  
Ziwen Yu ◽  
...  

Background. Huangkui capsule (HKC) comprises the total flavonoid extract of flowers of Abelmoschus manihot (L.) Medicus. This study aimed to explore the effects of HKC on lipopolysaccharide- (LPS-) induced acute lung injury (ALI) in mice and LPS-stimulated RAW 264.7 cells. Methods. Enzyme-linked immunosorbent assay, histopathology, spectrophotometry, and quantitative real-time polymerase chain reaction were used for the assessments. Statistical analysis was performed using a one-way analysis of variance. Results. LPS significantly increased lung inflammation, neutrophil infiltration, and oxidative stress and downregulated lung miR-451 expression. Treatment with HKC dramatically attenuated the lung wet/dry weight ratio, reduced the total cell count in the bronchoalveolar lavage fluid (BALF), and inhibited myeloperoxidase activity in the lung tissues 24 h after LPS challenge. Histopathological analysis demonstrated that HKC attenuated LPS-induced tissue oedema and neutrophil infiltration in the lung tissues. Additionally, the concentrations of tumour necrosis factor- (TNF-) α and interleukin- (IL-) 6 in BALF and IL-6 in the plasma reduced after HKC administration. Moreover, HKC could enhance glutathione peroxidase and catalase activities and upregulate the expression of miR-451 in the lung tissues. In vitro experiments revealed that HKC inhibited the production of nitric oxide, TNF-α, and IL-6 in LPS-induced RAW 264.7 cells and mouse primary peritoneal macrophages. Additionally, HKC downregulated LPS-induced transcription of TNF-α and IL-6 in RAW 264.7 cells. Conclusions. These findings suggest that HKC has anti-inflammatory and antioxidative effects that may protect mice against LPS-induced ALI and macrophage activation.


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