scholarly journals Dexmedetomidine Promotes Alveolar Fluid Clearance by Upregulating Na,K-ATPase Expression in a Rat Model of Acute Lung Injury via α2 AR/PI3K/Akt Pathway

2021 ◽  
Author(s):  
Mingzhu Xia ◽  
Zhi Huang ◽  
Mingyu Xu ◽  
Chao Hai ◽  
Wenbo Diao ◽  
...  
Keyword(s):  
Acute Lung Injury ◽  
Lung Injury ◽  
Pulmonary Edema ◽  
Molecular Mechanisms ◽  
A549 Cells ◽  
Lung Injury Score ◽  
Alveolar Fluid Clearance ◽  
Apoptosis Rate ◽  
Tnf Α

Abstract Our previous studies have shown that Dexmedetomidine (Dex), α2 adrenergic receptor (α2AR) agonist, reduces pulmonary edema in LPS-induced acute lung injury (ALI), but the mechanism is not clear. The purpose of this study is to explore whether Dex promotes AFC by upregulating the expression of Na,K-ATPase in LPS-induced ALI and possible molecular mechanisms. Histology of the lungs was assayed with H-E staining, and the lung injury score was calculated. PaO2, PaO2/FiO2 , the lung index, wet/dry (W/D) ratio of the lung tissues and alveolar fluid clearance(AFC) was measured; The concentrations of TNF-α, IL-1β, IL-6 in bronchoalveolar lavage fluid (BALF) and serum were measured. Myeloperoxidase (MPO) activity in lung tissues were determined. The apoptosis rate of A549 cells and the expression of Bcl-2 and Bax were evaluated. The expression of Na,K-ATPase , p-PI3K and p-Akt in vivo and in vitro were evaluated. Dex significantly alleviated lung tissue injury induced by LPS. Dex treatment reduced the W/D, lung index and MPO activity, increased PaO2, PaO2/FiO2 and AFC in LPS-induced ALI. In addition, Dex reduced the concentrations of TNF-α, IL-β and IL-6 in BALF and serum. Dex reduced the apoptosis rate, up-regulated the expression of Bcl-2 and down-regulated the expression of Bax in LPS-stimulated A549 cells. Furthermore, Dex increased the expression of α1Na,K-ATPase, β1 Na,K-ATPase and p-PI3K , p-Akt in vivo and vitro. However, these effects of Dex were partially reversed by the α2AR inhibitor yohim-bine or PI3K inhibitor LY294002. Collectively, these results suggest that Dex attenuates pulmonary edema by stimulating AFC via upregulating the Na,K-ATPase expressi-on in LPS-induced acute lung injury by modulating the α2AR/PI3K/Akt signaling pathway.

scholarly journals Dexmedetomidine alleviates pulmonary edema through the epithelial sodium channel (ENaC) via the PI3K/Akt/Nedd4-2 pathway in LPS-induced acute lung injury

2021 ◽  
Author(s):  
Yuanxu Jiang ◽  
Mingzhu Xia ◽  
Jing Xu ◽  
Qiang Huang ◽  
Zhongliang Dai ◽  
...  
Keyword(s):  
Acute Lung Injury ◽  
Lung Injury ◽  
Sodium Channel ◽  
Pulmonary Edema ◽  
Cell Injury ◽  
A549 Cells ◽  
Alveolar Epithelial ◽  
Phosphorylated Akt ◽  
Epithelial Sodium Channel Enac

AbstractDexmedetomidine (Dex), a highly selective α2-adrenergic receptor (α2AR) agonist, has an anti-inflammatory property and can alleviate pulmonary edema in lipopolysaccharide (LPS)-induced acute lung injury (ALI), but the mechanism is still unclear. In this study, we attempted to investigate the effect of Dex on alveolar epithelial sodium channel (ENaC) in the modulation of alveolar fluid clearance (AFC) and the underlying mechanism. Lipopolysaccharide (LPS) was used to induce acute lung injury (ALI) in rats and alveolar epithelial cell injury in A549 cells. In vivo, Dex markedly reduced pulmonary edema induced by LPS through promoting AFC, prevented LPS-induced downregulation of α-, β-, and γ-ENaC expression, attenuated inflammatory cell infiltration in lung tissue, reduced the concentrations of TNF-α, IL-1β, and IL-6, and increased concentrations of IL-10 in bronchoalveolar lavage fluid (BALF). In A549 cells stimulated with LPS, Dex attenuated LPS-mediated cell injury and the downregulation of α-, β-, and γ-ENaC expression. However, all of these effects were blocked by the PI3K inhibitor LY294002, suggesting that the protective role of Dex is PI3K-dependent. Additionally, Dex increased the expression of phosphorylated Akt and reduced the expression of Nedd4-2, while LY294002 reversed the effect of Dex in vivo and in vitro. Furthermore, insulin-like growth factor (IGF)-1, a PI3K agonists, promoted the expression of phosphorylated Akt and reduced the expression of Nedd4-2 in LPS-stimulated A549 cells, indicating that Dex worked through PI3K, and Akt and Nedd4-2 are downstream of PI3K. In conclusion, Dex alleviates pulmonary edema by suppressing inflammatory response in LPS-induced ALI, and the mechanism is partly related to the upregulation of ENaC expression via the PI3K/Akt/Nedd4-2 signaling pathway.

scholarly journals Baicalin Liposome Alleviates Lipopolysaccharide-Induced Acute Lung Injury in Mice via Inhibiting TLR4/JNK/ERK/NF-κB Pathway

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Yu Long ◽  
Yan Xiang ◽  
Songyu Liu ◽  
Yulu Zhang ◽  
Jinyan Wan ◽  
...  
Keyword(s):  
Acute Lung Injury ◽  
Lung Injury ◽  
Lung Injury Score ◽  
Therapeutic Effects ◽  
Dependent Manner ◽  
Scutellaria Baicalensis Georgi ◽  
Tnf Α ◽  
Anti Inflammatory ◽  
Novel Drug

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are challenging diseases with the high mortality in a clinical setting. Baicalin (BA) is the main effective constituent isolated from the Chinese medical herb Scutellaria baicalensis Georgi, and studies have proved that it has a protective effect on ALI induced by lipopolysaccharide (LPS) due to the anti-inflammatory efficacy. However, BA has low solubility which may limit its clinical application. Hence, we prepared a novel drug delivery system—Baicalin liposome (BA-LP) in previous research—which can improve some physical properties of BA. Therefore, we aimed to explore the effect of BA-LP on ALI mice induced by LPS. In pharmacokinetics study, the values of t 1 / 2 and AUC0- t in the BA-LP group were significantly higher than that of the BA group in normal mice, indicating that BA-LP could prolong the duration time in vivo of BA. The BA-LP group also showed a higher concentration in lung tissues than the BA group. Pharmacodynamics studies showed that BA-LP had a better effect than the BA group at the same dosage on reducing the W/D ratio, alleviating the lung injury score, and decreasing the proinflammatory factors (TNF-α, IL-1β) and total proteins in bronchoalveolar lavage fluids (BALF). In addition, the therapeutic effects of BA-LP showed a dose-dependent manner. Western blot analysis indicated that the anti-inflammatory action of BA could be attributed to the inhibition of the TLR4-NFκBp65 and JNK-ERK signaling pathways. These results suggest that BA-LP could be a valuable therapeutic candidate in the treatment of ALI.

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

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.

Shen-Fu Attenuates Endotoxin-Induced Acute Lung Injury in Rats

2006 ◽  
Vol 34 (04) ◽  
pp. 613-621 ◽  
Author(s):  
Yanning Qian ◽  
Jie Sun ◽  
Zhongyun Wang ◽  
Jianjun Yang
Keyword(s):  
Acute Lung Injury ◽  
Lung Injury ◽  
Pulmonary Inflammation ◽  
Weight Ratio ◽  
Dry Weight ◽  
Nf Kappa B ◽  
Lung Weight ◽  
Tnf Α ◽  
Male Wistar Rats

Sepsis is associated with the highest risk of progression to acute lung injury or acute respiratory distress syndrome. Shen-Fu has been advocated to treat many severely ill patients. Our study was designed to investigate the effect of Shen-Fu on endotoxin-induced acute lung injury in vivo. Adult male Wistar rats were randomly divided into 6 groups: controls; those challenged with endotoxin (5 mg/kg) and treated with saline; those challenged with endotoxin (5 mg/kg) and treated with Shen-Fu (1 mg/kg); those challenged with endotoxin (5 mg/kg) and treated with Shen-Fu (10 mg/kg); increase challenged with endotoxin (5 mg/kg) and treated with Shen-Fu (100 mg/kg); saline injected and treated with Shen-Fu (100 mg/kg). TNF-α, IL-6, and NF-kappa B were investigated in the lung two hours later. Myeloperoxidase (MPO) activity and wet/dry weight ratio were investigated six hours later. Intravenous administration of endotoxin provoked significant lung injury, which was characterized by increment increase of MPO activity and wet/dry lung weight ratio, and TNF-α and IL-6 expression and NF-kappa B activation. Shen-Fu (10,100 mg/kg) decreased MPO activity and wet/dry weight ratio and inhibited TNF-α and IL-6 production, endotoxin-induced NF-kappa B activation. Our results indicated that Shen-Fu at a dose of higher than 10 mg/kg inhibited endotoxin-induced pulmonary inflammation in vivo.

scholarly journals Role of LecA and LecB Lectins in Pseudomonas aeruginosa-Induced Lung Injury and Effect of Carbohydrate Ligands

2009 ◽  
Vol 77 (5) ◽  
pp. 2065-2075 ◽  
Author(s):  
Chanez Chemani ◽  
Anne Imberty ◽  
Sophie de Bentzmann ◽  
Maud Pierre ◽  
Michaela Wimmerová ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Acute Lung Injury ◽  
Lung Injury ◽  
Parental Strain ◽  
A549 Cells ◽  
Carbohydrate Ligands ◽  
Vitro Model

ABSTRACT Pseudomonas aeruginosa is a frequently encountered pathogen that is involved in acute and chronic lung infections. Lectin-mediated bacterium-cell recognition and adhesion are critical steps in initiating P. aeruginosa pathogenesis. This study was designed to evaluate the contributions of LecA and LecB to the pathogenesis of P. aeruginosa-mediated acute lung injury. Using an in vitro model with A549 cells and an experimental in vivo murine model of acute lung injury, we compared the parental strain to lecA and lecB mutants. The effects of both LecA- and Lec B-specific lectin-inhibiting carbohydrates (α-methyl-galactoside and α-methyl-fucoside, respectively) were evaluated. In vitro, the parental strain was associated with increased cytotoxicity and adhesion on A549 cells compared to the lecA and lecB mutants. In vivo, the P. aeruginosa-induced increase in alveolar barrier permeability was reduced with both mutants. The bacterial burden and dissemination were decreased for both mutants compared with the parental strain. Coadministration of specific lectin inhibitors markedly reduced lung injury and mortality. Our results demonstrate that there is a relationship between lectins and the pathogenicity of P. aeruginosa. Inhibition of the lectins by specific carbohydrates may provide new therapeutic perspectives.

scholarly journals Stem cell conditioned medium improves acute lung injury in mice: in vivo evidence for stem cell paracrine action

2012 ◽  
Vol 303 (11) ◽  
pp. L967-L977 ◽  
Author(s):  
Lavinia Ionescu ◽  
Roisin N. Byrne ◽  
Tim van Haaften ◽  
Arul Vadivel ◽  
Rajesh S. Alphonse ◽  
...  
Keyword(s):  
Stem Cell ◽  
Acute Lung Injury ◽  
Lung Injury ◽  
Conditioned Medium ◽  
Lung Fibroblasts ◽  
Lung Injury Score ◽  
M2 Macrophage ◽  
Arginase 1 ◽  
Igf I

Mortality and morbidity of acute lung injury and acute respiratory distress syndrome remain high because of the lack of pharmacological therapies to prevent injury or promote repair. Mesenchymal stem cells (MSCs) prevent lung injury in various experimental models, despite a low proportion of donor-derived cell engraftment, suggesting that MSCs exert their beneficial effects via paracrine mechanisms. We hypothesized that soluble factors secreted by MSCs promote the resolution of lung injury in part by modulating alveolar macrophage (AM) function. We tested the therapeutic effect of MSC-derived conditioned medium (CdM) compared with whole MSCs, lung fibroblasts, and fibroblast-CdM. Intratracheal MSCs and MSC-CdM significantly attenuated lipopolysaccharide (LPS)-induced lung neutrophil influx, lung edema, and lung injury as assessed by an established lung injury score. MSC-CdM increased arginase-1 activity and Ym1 expression in LPS-exposed AMs. In vivo, AMs from LPS-MSC and LPS-MSC CdM lungs had enhanced expression of Ym1 and decreased expression of inducible nitric oxide synthase compared with untreated LPS mice. This suggests that MSC-CdM promotes alternative macrophage activation to an M2 “healer” phenotype. Comparative multiplex analysis of MSC- and fibroblast-CdM demonstrated that MSC-CdM contained several factors that may confer therapeutic benefit, including insulin-like growth factor I (IGF-I). Recombinant IGF-I partially reproduced the lung protective effect of MSC-CdM. In summary, MSCs act through a paracrine activity. MSC-CdM promotes the resolution of LPS-induced lung injury by attenuating lung inflammation and promoting a wound healing/anti-inflammatory M2 macrophage phenotype in part via IGF-I.

scholarly journals Nasal potential difference to detect Na+channel dysfunction in acute lung injury

2011 ◽  
Vol 300 (3) ◽  
pp. L305-L318 ◽  
Author(s):  
R. Mac Sweeney ◽  
H. Fischer ◽  
D. F. McAuley
Keyword(s):  
Acute Lung Injury ◽  
Lung Injury ◽  
Ion Channel ◽  
Pulmonary Edema ◽  
Potential Difference ◽  
Na Channel ◽  
Alveolar Epithelial ◽  
Nasal Potential Difference ◽  
Respiratory Epithelial

Pulmonary fluid clearance is regulated by the active transport of Na+and Cl−through respiratory epithelial ion channels. Ion channel dysfunction contributes to the pathogenesis of various pulmonary fluid disorders including high-altitude pulmonary edema (HAPE) and neonatal respiratory distress syndrome (RDS). Nasal potential difference (NPD) measurement allows an in vivo investigation of the functionality of these channels. This technique has been used for the diagnosis of cystic fibrosis, the archetypal respiratory ion channel disorder, for over a quarter of a century. NPD measurements in HAPE and RDS suggest constitutive and acquired dysfunction of respiratory epithelial Na+channels. Acute lung injury (ALI) is characterized by pulmonary edema due to alveolar epithelial-interstitial-endothelial injury. NPD measurement may enable identification of critically ill ALI patients with a susceptible phenotype of dysfunctional respiratory Na+channels and allow targeted therapy toward Na+channel function.

scholarly journals Inhibition of Inflammation and Regulation of AQPs/ENaCs/Na+-K+-ATPase Mediated Alveolar Fluid Transport by Total Flavonoids Extracted From Nervilia fordii in Lipopolysaccharide-induced Acute Lung Injury

2021 ◽  
Vol 12 ◽  
Author(s):  
Shuomiao Yin ◽  
Meizhu Ding ◽  
Long Fan ◽  
Xuhua Yu ◽  
Ziyao Liang ◽  
...  
Keyword(s):  
Acute Lung Injury ◽  
Lung Injury ◽  
Pulmonary Edema ◽  
Active Transport ◽  
Inflammatory Cytokines ◽  
Fluid Transport ◽  
Oxygenation Index ◽  
Total Flavonoids ◽  
Sd Rats ◽  
Tnf Α

Aims: The occurrence of vascular permeability pulmonary edema in acute lung injury (ALI) is related to the imbalance of alveolar fluid transport. Regulating the active transport of alveolar fluid by aquaporins (AQPs), epithelial sodium channels (ENaCs), and Na+-K+-ATPase can effectively reduce the edema fluid in the alveolar cavity and protect against ALI. We evaluated the therapeutic effects of total flavonoids, extracted from Nervilia fordii (TFENF), and investigated its potential mechanisms of alveolar fluid transport in a rat ALI model.Materials and methods: A model of lipopolysaccharide (LPS, 5 mg/kg)-induced ALI was established in Sprague-Dawley (SD) rats through the arteriae dorsalis penis. SD rats were divided into six groups, including the vehicle, LPS model, TFENF (6 mg/kg, 12 mg/kg, 24 mg/kg), and dexamethasone group (DEX group, 5 mg/kg). The wet-to-dry (W/D) lung weight ratio, oxygenation index, and histopathological observation were used to evaluate the therapeutic effect of TFENF. The mRNA expression of AQPs, ENaCs, and pro-inflammatory cytokines was determined using real-time polymerase chain reaction, whereas protein expression was determined using immunohistochemistry. The Na+-K+-ATPase activity was assessed using enzyme-linked immunosorbent assay.Results: LPS significantly stimulated the production of inflammatory mediators including tumor necrosis factor (TNF)-α and interleukin (IL)-1β, and disrupted the water transport balance in the alveolar cavity by inhibiting AQPs/ENaCs/Na+-K+-ATPase. Pretreatment with TFENF reduced the pathological damage and W/D ratio of the lungs and ameliorated the arterial blood oxygen partial pressure (PaO2) and oxygenation index. TFENF further decreased the mRNA level of TNF-α and IL-1β; increased the expression of AQP-1, AQP-5, αENaC, and βENaC; and increased Na+-K+-ATPase activity. Moreover, the regulation of AQPs, βENaC, and Na+-K+-ATPase and the inhibition of TNF-α and IL-1β by TFENF were found to be dose dependent.Conclusion: TFENF protects against LPS-induced ALI, at least in part, through the suppression of inflammatory cytokines and regulation of the active transport capacity of AQPs/ENaCs/Na+-K+-ATPase. These findings suggest the therapeutic potential of TFENF as phytomedicine to treat inflammation and pulmonary edema in ALI.

Validation of novel hub genes and molecular mechanisms in acute lung injury using an integrative bioinformatics approach

2021 ◽  
Author(s):  
Qingchun Liang ◽  
Qin Zhou ◽  
Jinhe Li ◽  
Zhugui Chen ◽  
Zhihao Zhang ◽  
...  
Keyword(s):  
Gene Expression ◽  
Acute Lung Injury ◽  
Lung Injury ◽  
Molecular Mechanisms ◽  
Molecular Biomarkers ◽  
Functional Enrichment ◽  
Lung Injury Score ◽  
Control Group ◽  
High Morbidity ◽  
Hub Genes

Abstract Acute lung injury (ALI) is an inflammatory pulmonary disease that can easily develop into serious acute respiratory distress syndrome, which has high morbidity and mortality. However, the molecular mechanism of ALI remains unclear, and few molecular biomarkers for diagnosis and treatment have been identified. In this study, we aimed to identify novel molecular biomarkers using a bioinformatics approach. Gene expression data were obtained from the Gene Expression Omnibus database, co-expressed differentially expressed genes (CoDEGs) were identified using R software, and further functional enrichment analyses were conducted using the online tool Database for Annotation, Visualization, and Integrated Discovery. A protein–protein interaction network was established using the STRING database and Cytoscape software. Lipopolysaccharide (LPS)-induced ALI mouse model was constructed and verified. The hub genes were screened and validated in vivo. The transcription factors (TFs) and miRNAs associated with the hub genes were predicted using the NetworkAnalyst database. In total, 71 CoDEGs were screened and found to be mainly involved in the cytokine–cytokine receptor interactions, and the tumor necrosis factor and malaria signaling pathways. Animal experiments showed that the lung injury score, bronchoalveolar lavage fluid protein concentration, and wet-to-dry weight ratio were higher in the LPS group than those in the control group. Real-time polymerase chain reaction analysis indicated that most of the hub genes such as colony-stimulating factor 2 (Csf2) were overexpressed in the LPS group. A total of 20 TFs including nuclear respiratory factor 1 (NRF1) and two miRNAs were predicted to be regulators of the hub genes. In summary, Csf2 may serve as a novel diagnostic and therapeutic target for ALI. NRF1 and mmu-mir-122-5p may be key regulators in the development of ALI.

scholarly journals Contribution of CFTR to Alveolar Fluid Clearance by Lipoxin A4via PI3K/Akt Pathway in LPS-Induced Acute Lung Injury

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Yi Yang ◽  
Yang Cheng ◽  
Qing-Quan Lian ◽  
Li Yang ◽  
Wei Qi ◽  
...  
Keyword(s):  
Acute Lung Injury ◽  
Lung Injury ◽  
Protein Expression ◽  
Specific Inhibitor ◽  
Akt Pathway ◽  
Alveolar Type ◽  
Alveolar Fluid Clearance ◽  
Cftr Protein

The lipoxins are the first proresolution mediators to be recognized and described as the endogenous “braking signals” for inflammation. We evaluated the anti-inflammatory and proresolution bioactions of lipoxin A4in our lipopolysaccharide (LPS-)induced lung injury model. We demonstrated that lipoxin A4significantly improved histology of rat lungs and inhibited IL-6 and TNF-αin LPS-induced lung injury. In addition, lipoxin A4increased alveolar fluid clearance (AFC) and the effect of lipoxin A4on AFC was abolished byCFTRinh-172(a specific inhibitor of CFTR). Moreover, lipoxin A4could increase cystic fibrosis transmembrane conductance regulator (CFTR) protein expressionin vitroandin vivo. In rat primary alveolar type II (ATII) cells, LPS decreased CFTR protein expression via activation of PI3K/Akt, and lipoxin A4suppressed LPS-stimulated phosphorylation of Akt. These results showed that lipoxin A4enhanced CFTR protein expression and increased AFC via PI3K/Akt pathway. Thus, lipoxin A4may provide a potential therapeutic approach for acute lung injury.

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