scholarly journals miR-20a attenuates acute lung injury in septic rats via targeting TLR4

2021 ◽  

Background: Sepsis is most likely to cause lung damage in patients, and the detection rate and mortality rate are high. Here, we investigated the expression of miR-20a in sepsis-induced acute lung injury (ALI) rats and its effect on inflammatory response, and reveal its possible molecular mechanism. Method: The model of acute lung injury caused by sepsis in rats was established by cecal ligation and puncture. The expression of miR-20a in lung tissue was determined by RT-qPCR. Acute lung injury rats were injected with 5 nmol miR-20a agomir or agomir NC every day for 3 days. Rats were sacrificed by arterial bleeding and lung tissues were removed. Serum interleukin (IL) -1β, IL-6, and tumor necrosis factor alpha (TNF-α) were detected by ELISA. HE staining was used to observe the pathology of lung tissue and calculate the pathological score of lung injury. Western blot to determine the level of TLR4 and nuclear transcription factor κB p65 (NF-κB p65) protein in lung tissue. The luciferase reporter assay was used to verify the binding effect of miR-20a on the 3 non-coding TLR4. Results: We found that compared with that in Normal group, the expression of miR-20a in lung tissues of rats with ALI was decreased (p < 0.05). In miR-20a agomir group, the plasma level of IL-1β, IL-6, and TNF-α was significantly lower than that in agomir NC group and ALI group (p < 0.05), while higher than those in Normal group (p < 0.05). The HE staining results showed that the pathological score of lung injury in rats in miR-20a agomir group was lower than that of agomir NC group and ALI group (p < 0.05). Compared with agomir NC group and ALI group, the expression of TLR4 and NF-κB p65 in miR-20a agomir group was decreased (p < 0.01). The luciferase reporting experiment confirmed that TLR4 was a target gene of miR-20a. Conclusion: To sum up, miR-20a exerts a protective effect on sepsis-induced ALI rats through its anti-inflammatory effect. The targeting of TLR4 by miR-20a may be an effective method to reduce the inflammatory response in sepsis-induced ALI.

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Tao Li ◽  
Gui Xiao ◽  
Sipin Tan ◽  
Xueyan Shi ◽  
Leijing Yin ◽  
...  

Heat shock factor 1 (HSF1) is a transcription factor involved in the heat shock response and other biological processes. We have unveiled here an important role of HSF1 in acute lung injury (ALI). HSF1 knockout mice were used as a model of lipopolysaccharide- (LPS-) induced ALI. Lung damage was aggravated, and macrophage infiltration increased significantly in the bronchoalveolar lavage fluid (BALF) and lung tissue of HSF-/- mice compared with the damage observed in HSF1+/+ mice. Upon LPS stimulation, HSF-/- mice showed higher levels of monocyte chemoattractant protein-1 (MCP-1) in the serum, BALF, and lung tissue and increased the expression of MCP-1 and chemokine (C-C motif) receptor 2 (CCR2) on the surface of macrophages compared with those in HSF1+/+. Electrophoretic mobility shift assays (EMSA) and dual luciferase reporter assays revealed that HSF1 could directly bind to heat shock elements (HSE) in the promoter regions of MCP-1 and its receptor CCR2, thereby inhibiting the expression of both genes. We concluded that HSF1 attenuated LPS-induced ALI in mice by directly suppressing the transcription of MCP-1/CCR2, which in turn reduced macrophage infiltration.


2021 ◽  
Vol 49 (5) ◽  
pp. 117-124
Author(s):  
Wenmei Liang ◽  
Li Guo ◽  
Tonghua Liu ◽  
Song Qin

Background: Sepsis is a systemic inflammatory response syndrome and leads to patient’s death. Objective: To investigate the effect of myocyte enhancer factor 2 (MEF2C) on acute lung injury (ALI) with sepsis and its possible mechanism.Material and Methods: The cecal ligation and puncture (CLP)-induced sepsis rat model was established. The lung injury was determined by lung wet–dry weight ratio, the concentration of inflammatory cytokines, including tumor necrosis factor-α (TNF-α), Interlukin (IL)-6, IL-1β, and IL-10, were measured by the enzyme-linked-immunosorbent serologic assay kit. The cell apoptosis was detected by TUNEL staining assay.Results: Interestingly, MEF2C was down-regulated in this model. Moreover, adeno-associated virus (AAV)-MEF2C treatment markedly suppressed TNF-α, IL-1β, and IL-6 concentrations but promoted IL-10 concentration in serum in CLP-challenged rats. Besides, overexpression of MEF2C alleviates CLP-induced lung injury. Interestingly, AAV-MEF2C treatment was confirmed to suppress apoptosis in CLP-induced sepsis rats as well as promote aquaporin APQ1 expres-sion. Mechanistically, the rescue experiments indicated that MEF2C alleviated CLP-induced lung inflammatory response and apoptosis via up-regulating AQP1.Conclusion: In summary, overexpression of MEF2C suppressed CLP-induced lung inflamma-tory response and apoptosis via up-regulating AQP1, providing a novel therapeutic target for sepsis-induced ALI.


Author(s):  
Guang Li ◽  
Bo Wang ◽  
Xiangchao Ding ◽  
Xinghua Zhang ◽  
Jian Tang ◽  
...  

AbstractExtracellular vesicles (EVs) can be used for intercellular communication by facilitating the transfer of miRNAs from one cell to a recipient cell. MicroRNA (miR)-210-3p is released into the blood during sepsis, inducing cytokine production and promoting leukocyte migration. Thus, the current study aimed to elucidate the role of plasma EVs in delivering miR-210-3p in sepsis-induced acute lung injury (ALI). Plasma EVs were isolated from septic patients, after which the expression of various inflammatory factors was measured using enzyme-linked immunosorbent assay. Cell viability and apoptosis were measured via cell counting kit-8 and flow cytometry. Transendothelial resistance and fluorescein isothiocyanate fluorescence were used to measure endothelial cell permeability. Matrigel was used to examine the tubulogenesis of endothelial cells. The targeting relationship between miR-210-3p and ATG7 was assessed by dual-luciferase reporter assays. The expression of ATG7 and autophagy-related genes was determined to examine autophagic activation. A sepsis mouse model was established by cecal ligation and puncture (CLP)-induced surgery. The level of miR-210-3p was highly enriched in septic EVs. MiR-210-3p enhanced THP-1 macrophage inflammation, BEAS-2B cell apoptosis, and HLMVEC permeability while inhibiting angiogenesis and cellular activity. MiR-210-3p overexpression reduced ATG7 and LC3II/LC3I expression and increased P62 expression. Improvements in vascular density and autophagosome formation, increased ATG7 expression, and changes in the ratio of LC3II/LC3I were detected, as well as reduced P62 expression, in adenovirus-anti-miR-210-3p treated mice after CLP injury. Taken together, the key findings of the current study demonstrate that plasma EVs carrying miR-210-3p target ATG7 to regulate autophagy and inflammatory activation in a sepsis-induced ALI model.


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.


2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Jing Guo ◽  
Min Li ◽  
Yi Yang ◽  
Lin Zhang ◽  
Li-wei Zhang ◽  
...  

Abstract Background The complement system plays a critical role as the pathogenic factor in the models of acute lung injury due to various causes. Cobra venom factor (CVF) is a commonly used complement research tool. The CVF can cause acute inflammation in the lung by producing complement activation components. Atorvastatin (ATR) is a 3-hydroxy-3-methylglutaryl coenzyme A inhibitor approved for control of plasma cholesterol levels. This inhibitor can reduce the acute pulmonary inflammatory response. However, the ability of ATR in treating acute lung inflammation caused by complement activation is still unknown. Therefore, we investigated the effect of ATR on lung inflammation in mice induced by activation of the complement alternative pathway in this study. Methods ATR (10 mg/kg/day via oral gavage) was administered for 7 days before tail vein injection of CVF (25 μg/kg). On the seventh day, all mice were sacrificed 1 h after injection. The lung lobe, bronchoalveolar lavage fluid (BALF), and blood samples were collected. The myeloperoxidase (MPO) activity of the lung homogenate, the leukocyte cell count, and the protein content of BALF were measured. The levels of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), P-selectin, and Intercellular cell adhesion molecule-1 (ICAM-1) in BALF and serum were determined by enzyme-linked immunosorbent assay. The pathological change of the lung tissue was observed by hematoxylin and eosin staining. The deposition of C5b-9 in the lung tissue was detected by immunohistochemistry. The phosphorylation of NF-κB p65 in the lung tissues was examined by immunohistochemistry and western blotting. Results The lung inflammation levels were determined by measuring the leukocyte cell numbers and protein content of BALF, the lung MPO activity, and expression and staining of the inflammatory mediators (IL-6 and TNF-α), and adhesion molecules (P-selectin and ICAM-1) for lung lesion. A significant reduction in the lung inflammation levels was observed after 7 days in ATR pre-treated mice with a CVF-induced lung disease. Deposition of C5b-9 was significantly alleviated by ATR pretreatment. Early intervention with ATR significantly reduced the development of acute lung inflammation on the basis of phosphorylation of NF-κB p65 in the lung. Conclusion These findings suggest the identification of ATR treatment for the lung inflammation induced by activating the complement system on the basis of its anti-inflammatory response. Together with the model replicating the complement activating characteristics of acute lung injury, the results may be translatable to the overactivated complement relevant diseases.


2020 ◽  
Vol 19 (3) ◽  
pp. 533-539
Author(s):  
Qinghai You ◽  
Jinmei Wang ◽  
Lijuan Jiang ◽  
Yuanmin Chang ◽  
Wenmei Li

Purpose: To investigate the therapeutic effect of aqueous extract of Aconitum carmichaelii Debeaux (AEACD) on sepsis-induced acute lung injury (ALI), as well as explore the underlying mechanism of action. Methods: C57BL/6 mice were treated with AEACD by gavage (4.0 g/kg/day) for 5 days before cecal ligation and puncture (CLP) challenge. After 24 h, the pathological morphology of lung tissue and the biochemical parameters in bronchoalveolar lavage fluid (BALF) were determined by H&E staining and enzyme-linked immunosorbent assay (ELISA). Furthermore, the total protein content and lactate dehydrogenase (LDH) level of BALF, as well as the oxidative biomarkers (malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD)) were evaluated in the lung homogenates by ELISA assay. The levels of pro-inflammatory cytokines, TNFα, IL-1β, and IL-6, in lung tissue were measured by qRT-PCR or ELISA. Finally, key proteins in Toll-like receptor 4 (TLR4)/nuclear factor-κB (NF-κB) pathway in lung tissue were evaluated by western blot. Results: CLP challenge induced abnormal changes in the histological structures of lung tissue, lung wet-to-dry weight (W/D) ratio, protein content and LDH levels of BALF, which were remarkably reversed by AEACD. In addition, AEACD decreased MDA levels, and increased GSH levels and SOD activity in the lung tissue of CLP–treated mice (p < 0.05). Furthermore, AEACD attenuated the CLP challengeinduced upregulation of TNFα, IL-1β, and IL-6. Finally, AEACD inactivated TLR4/NF-κB pathway by upregulating IκBα and downregulating TLR4 and phosphorylated-p65 levels. Conclusion: AEACD administration protects mice against sepsis-induced ALI through the regulation of oxidative stress and inflammatory responses in lung tissues. The underlying mechanism occurs by inhibiting TLR4/NF-κB signaling pathway. Keywords: Aconitum carmichaelii Debeaux, Acute lung injury, Sepsis, TLR4, NF-κB


2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Yan Zhu ◽  
Taocheng Meng ◽  
Aichen Sun ◽  
Jintao Li ◽  
Jinlai Li

Objective. This study aimed to explore the role of angelica polysaccharide (AP) in sepsis-induced acute lung injury (ALI) and its underlying molecular mechanism. Methods. A sepsis model of cecal ligation and puncture (CLP) in male BALB/C mice was used. Then, 24 h after CLP, histopathological changes in lung tissue, lung wet/dry weight ratio, and inflammatory cell infiltration were analyzed. Next, levels of inflammatory cytokines (tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-6, and IL-18), as well as the activity of myeloperoxidase (MPO), malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione (GSH), were measured to assess the role of AP. The protein expression of NF-κB p65, p-NF-κB p65, IκBα, p-IκBα, nucleotide-binding domain- (NOD-) like receptor protein 3 (NLRP3), ASC, and caspase-1 was detected by western blot. In addition, the expression of p-NF-κB p65 and NLRP3 was detected by immunohistochemistry. Results. AP treatment ameliorated CLP-induced lung injury and lung edema, as well as decreased the number of total cells, neutrophils, and macrophages in bronchoalveolar lavage fluid (BALF). AP reduced the levels of TNF-α, IL-1β, IL-6, and IL-18 in BALF, as well as in serum. Moreover, AP decreased MPO activity and MDA content, whereas increased SOD and GSH levels. AP inhibited the expression of p-NF-κB p65, p-IκBα, NLRP3, ASC, and caspase-1, while promoted IκBα expression. Conclusion. This study demonstrated that AP exhibits protective effects against sepsis-induced ALI by inhibiting NLRP3 and NF-κB signaling pathways in mice.


2020 ◽  
Vol 8 (S1) ◽  
Author(s):  
Laura Chimenti ◽  
Luis Morales-Quinteros ◽  
Ferranda Puig ◽  
Marta Camprubi-Rimblas ◽  
Raquel Guillamat-Prats ◽  
...  

Abstract Background The animal experimental counterpart of human acute respiratory distress syndrome (ARDS) is acute lung injury (ALI). Most models of ALI involve reproducing the clinical risk factors associated with human ARDS, such as sepsis or acid aspiration; however, none of these models fully replicates human ARDS. Aim To compare different experimental animal models of ALI, based on direct or indirect mechanisms of lung injury, to characterize a model which more closely could reproduce the acute phase of human ARDS. Materials and methods Adult male Sprague-Dawley rats were subjected to intratracheal instillations of (1) HCl to mimic aspiration of gastric contents; (2) lipopolysaccharide (LPS) to mimic bacterial infection; (3) HCl followed by LPS to mimic aspiration of gastric contents with bacterial superinfection; or (4) cecal ligation and puncture (CLP) to induce peritonitis and mimic sepsis. Rats were sacrificed 24 h after instillations or 24 h after CLP. Results At 24 h, rats instilled with LPS or HCl-LPS had increased lung permeability, alveolar neutrophilic recruitment and inflammatory markers (GRO/KC, TNF-α, MCP-1, IL-1β, IL-6). Rats receiving only HCl or subjected to CLP had no evidence of lung injury. Conclusions Rat models of ALI induced directly by LPS or HCl-LPS more closely reproduced the acute phase of human ARDS than the CLP model of indirectly induced ALI.


Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 4285-4285
Author(s):  
John-Paul Tung ◽  
Denisa Meka ◽  
Annette J Sultana ◽  
Gabriela Simonova ◽  
Anne-Marie Christensen ◽  
...  

Abstract Background Transfusion-related acute lung injury (TRALI) has been the leading cause of transfusion-related morbidity and mortality in the UK and the USA in recent years. A threshold mechanism of TRALI has been proposed in which both patient factors (type and/or severity of clinical insult) and blood product factors (strength and/or concentration of antibodies or biological response modifiers) interact to surpass a threshold for TRALI development (Bux et al. Br J Haematol; 2007; 136: 788-99). The risk of developing antibody-mediated TRALI has been minimised by the introduction of risk-reduction strategies such as limiting the use of plasma from female donors. In contrast, there are no strategies currently in place to mitigate the development of non-antibody mediated TRALI as the mechanisms remain largely undefined. Previous studies have implicated non-polar lipids such as arachidonic acid and various species of hydroxyeicosatetranoic acid (HETE) in the development of non-antibody mediated TRALI (Silliman et al. Transfusion; 2011; 51: 2549-54), however the contribution of these lipids to the development of an inflammatory response in TRALI is poorly understood. Methodology Standard leucodepleted packed red blood cell (PRBC) units were sampled at either day (D) 2 (n=75) or at D42 (n=113). PRBC-supernatants were obtained via centrifugation, pooled (D2, D42) and levels of arachidonic acid, 5-, 12- and 15-HETE determined using commercial ELISA kits. In an in vitro transfusion model, fresh human whole blood (“recipient”; n=8 for each lipid) was mixed with combinations of culture media (control) or lipopolysaccharide (LPS, 0.23 µg/mL) as a first hit. A range of concentrations of either 5-HETE (200; 1,000; 2,500; 10,000; 250,000 pg/mL), 12-HETE (1,500; 5,000; 62,500; 250,000 pg/mL) or 15-HETE (150; 1,000; 2,000; 8,000 pg/mL) were added as the second hit, and incubated for 6 hours with the addition of a protein transport inhibitor. Neutrophil- and monocyte-specific inflammatory response was assessed using multi-colour flow cytometry (panel: IL-6, IL-8, IL-10, IL-12, IL-1α, IL-1β, TNF-α, MCP-1, IP-10, MIP-1α, MIP-1β). Significance was determined as P < 0.05 by one-way ANOVA with Bonferonni's correction used to determine dose response (indicated by asterisks). Results 5-, 12- and 15-HETE were all detectable in both of the PRBC supernatant pools, with levels increased in D42 compared to D2 (5-HETE: 20,347 vs. 3,449; 12-HETE: 240,967 vs. 1,572; 15-HETE: 7,900 vs. 934; all levels in pg/mL). Arachidonic acid was not detectable in either of the PRBC supernatant pools. In the absence of LPS as a first hit, the addition of non-polar lipids had a predominantly immunosuppressive effect in the transfusion model. 12-HETE suppressed monocyte production of MIP-1α* and neutrophil production of IL-6, IL-8 and IL-12. Also, 15-HETE modulated monocyte IL-8 production and reduced neutrophil production of IL-8, IL-12, IP-10, MIP-1α, MIP-1β and TNF-α. In contrast, in the presence of LPS as a first hit, a predominantly pro-inflammatory response was evident to these lipids. 12-HETE increased monocyte production of IL-1α, IL-8* and MIP-1β* as well as neutrophil production of IL-1α*, IP-10*, MCP-1, MIP-1α* and MIP-1β. In addition, 15-HETE increased neutrophil expression of IL-1α and IL-6, and 5-HETE modulated monocyte production of MIP-1β. Conclusions These data suggest that the non-polar lipid mediators investigated here, in particular 12-HETE, may contribute to TRALI pathogenesis. A storage related accumulation of 5-, 12- and 15-HETE was evident in leucodepleted PRBC units. The in vitro model indicated that exposure to these lipid mediators supressed the recipient inflammatory responses in the absence of LPS, but contributed to a pro-inflammatory profile in the presence of LPS as a first hit. Together these data provide further evidence of the importance of both patient (first hit) and blood component (second hit) factors in the development of TRALI. Furthermore, the dose-associated response observed for a number of inflammatory markers is consistent with the threshold hypothesis of TRALI pathogenesis. Disclosures No relevant conflicts of interest to declare.


2021 ◽  
Vol 41 (1) ◽  
Author(s):  
Wuquan Li ◽  
Wentao Zhang ◽  
Jun Liu ◽  
Yalong Han ◽  
He Jiang ◽  
...  

Abstract Excessive pulmonary inflammatory response is critical in the development of acute lung injury (ALI). Previously, microRNAs (miRNAs) have been recognized as an important regulator of inflammation in various diseases. However, the effects and mechanisms of miRNAs on inflammatory response in ALI remain unclear. Herein, we tried to screen miRNAs in the processes of ALI and elucidate the potential mechanism. Using a microarray assay, microRNA let-7e (let-7e) was chose as our target for its reported suppressive roles in several inflammatory diseases. Down-regulation of let-7e by antagomiR-let-7e injection attenuated LPS-induced acute lung injury. We also found that antagomiR-let-7e could obviously improve the survival rate in ALI mice. Moreover, antagomiR-let-7e treatment reduced the production of proinflammatory cytokines (i.e., TNF-α, IL-1β and IL-6) in bronchoalveolar lavage fluid (BALF) of LPS-induced ALI mice. Luciferase reporter assays confirmed that suppressor of cytokine signaling 1 (SOCS1), a powerful attenuator of nuclear factor kappa B (NF-κB) signaling pathway, was directly targeted and suppressed by let-7e in RAW264.7 cells. In addition, it was further observed that SOCS1 was down-regulated, and inversely correlated with let-7e expression levels in lung tissues of ALI mice. Finally, down-regulation of let-7e suppressed the activation of NF-κB pathway, as evidenced by the reduction of p-IκBα, and nuclear p-p65 expressions in ALI mice. Collectively, our findings indicate that let-7e antagomir protects mice against LPS-induced lung injury via repressing the pulmonary inflammation though regulation of SOCS1/NF-κB pathway, and let-7e may act as a potential therapeutic target for ALI.


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