Role In Acute Lung Injury Research Articles

Role of the Receptor for Advanced Glycation End Products in Heat Stress-Induced Endothelial Hyperpermeability in Acute Lung Injury.

ObjectiveTo study the role of the receptor for advanced glycation end products (RAGE) in endothelial barrier dysfunction induced by heat stress, to further explore the signal pathway by which RAGE contributes to heat-induced endothelia response, and thereby find a novel target for the clinical treatment of ALI (acute lung injury) induced by heatstroke.MethodsThis study established the animal model of heatstroke using RAGE knockout mice. We observed the role of RAGE in acute lung injury induced by heatstroke in mice by evaluating the leukocytes, neutrophils, and protein concentration in BALF (Bronchoalveolar lavage fluids), lung wet/dry ratio, histopathological changes, and the morphological ultrastructure of lung tissue and arterial blood gas analysis. To further study the mechanism, we established a heat stress model of HUVEC and concentrated on the role of RAGE and its signal pathway in the endothelial barrier dysfunction induced by heat stress, measuring Transendothelial electrical resistance (TEER) and western blot.ResultsRAGE played a key role in acute lung injury induced by heatstroke in mice. The mechanism C-Jun is located in the promoter region of the RAGE gene. C-Jun increased the RAGE protein expression while HSF1 suppressed RAGE protein expression. The overexpressed RAGE protein then increased HUVEC monolayer permeability by activating ERK and P38 MAPK under heat stress.ConclusionThis study indicates the critical role of RAGE in heat stress-induced endothelial hyperpermeability in acute lung injury and suggests that RAGE could be a potential therapeutic target in protecting patients against acute lung injury induced by heatstroke.

Immunosuppressive effects of mesenchymal stem cells on lung B cell gene expression in LPS-induced acute lung injury

BackgroundImmune system disorders play important roles in acute lung injury (ALI), and mesenchymal stem cell (MSC) treatment can reduce inflammation during ALI. In this study, we compared the changes in lung B cells during MSC treatment.MethodsWe investigated the effects of MSCs on lung B cells in a mouse model of lipopolysaccharide (LPS)-induced ALI. MSCs were administered intratracheally 4 h after LPS. As vehicle-treated controls, mice were treated with phosphate-buffered saline (PBS) containing 2% C57BL/6 (PBS group). Histopathological changes, survival rate, inflammatory factor levels, and the number of neutrophils in bronchoalveolar lavage fluid (BALF) were determined. Single-cell RNA sequencing (scRNA-Seq) analysis was performed to evaluate the transcriptional changes in lung B cells between the PBS, LPS, and LPS/MSC groups on days 3 and 7.ResultsMSC treatment ameliorated LPS-induced ALI, as indicated by the reductions in mortality, the levels of chemokines and cytokines in BALF, and the severity of lung tissue histopathology in ALI mice. Lung B cells in the PBS group remained undifferentiated and had an inhibitory phenotype. Based on our scRNA-Seq results, the differentially expressed genes (DEGs) in lung B cells in both the PBS group and LPS group were involved in chemotaxis processes and some proinflammatory pathways. MSC treatment inhibited the expression of chemokine genes that were upregulated by LPS and were related to the recruitment of neutrophils into lung tissues. Immunoglobulin-related gene expression was decreased in lung B cells of mice treated with LPS/MSC for 7 days. The DEGs regulated by MSCs were enriched in biological processes, including humoral immune response and apoptotic signaling.ConclusionsLung B cells played an important role in the effects of treatment of ALI with MSCs. These observations provide new insights into the mechanisms underlying the effects of MSC treatment for ALI.

Effect of adipose-derived mesenchymal stem cells and liraglutide on acute lung injury

Objective: To explore the protective effect of human adipose-derived mesenchymal stem cells (AD-MSCs) and liraglutide on lipopolysaccharide (LPS) -induced acute lung injury (ALI) . Methods: AD-MSCs were cultured in vitro and randomly divided into 3 groups: control group, LPS group (30 mg/L) , and LPS (30 mg/L) +liraglutide (10 nM) group. MTT assay was used to detect the proliferation of AD-MSCs at 6, 24, 48 and 72 h. Annexin V-FITC / PI double staining flow cytometry was used to detect the apoptosis of the cells. Western blot was used to detect the expression of apoptotic proteins cleaved caspase-3, Bax and Bcl-2 at 72 h in vitro. For the in vivo experiment, 60 male SPF BALB/c mice were randomly divided into 5 groups: control group, ALI group, ALI+AD-MSCs group, ALI+Liraglutide group, and ALI+AD-MSCs+Lraglutide group. The mice were sacrificed on day 2 and day 7 after LPS treatment. HE staining was used to examine the pathological changes of the lungs of mice, and the scores of lung injury were measured. The lung tissues of mice were examined by immunohistochemistry, and the expression of the marker protein Nanog of mesenchymal stem cells was observed. BALF was collected, and the number of BALF neutrophils was counted by Rayleigh Giemsa staining. The wet/dry specific gravity of mouse lung tissue was recorded. Results: The apoptosis of AD-MSCs stimulated by LPS was significantly higher than that of the control group (P<0.05) , and the proliferation of AD-MSCs at 6, 24, 48 and 72 h was significantly lower than that of the control group (all P<0.05) . The addition of Liraglutide reduced the apoptosis of AD-MSCs (P<0.05) , and promoted the proliferation of AD-MSC at 6, 24, 48 and 72 h. Compared with the control group, in the 2 d and 7 d model groups, the lung injury pathology of ALI group had lung injury, increased number of neutrophils in BALF (65.63±1.34 vs 1.74±0.17, 51.67±1.35 vs 1.55±0.13) ×10(4)/ml (all P<0.05) , and increased W/D of lung tissues. The expression level of Nanog protein was low in the 7 d model group. Compared with the ALI group, in 2 d and 7 d model groups, the ALI+AD-MSCs group, the ALI+liraglutide group, and the ALI+AD-MSCs+liraglutide group showed reduced lung injury pathology, and the number of neutrophils was decreased, (37.04±1.23, 29.17±0.68) ×10(4) / ml (all P<0.05) in the ALI+AD -MSCs group, (39.58±1.67, 35.42±0.25) ×10(4) / ml in the ALI+Liraglutide group (all P<0.05) and (28.54±0.37, 21.46±0.89) ×10(4)/ml (all P<0.05) in the ALI+AD-MSCs+Liraglutide group. Lung tissue W/D in the ALI+AD-MSCs group, ALI+Liraglutide group and ALI+AD-MSCs+Liraglutide group showed the same trend. Nanog protein expression increased in the 7 d model group. Conclusions: AD-MSCs play a protective role in acute lung injury in mice under the synergistic effect of liraglutide.

The angiotensin-converting enzyme 2/angiotensin (1–7)/mas axis protects against pyroptosis in LPS-induced lung injury by inhibiting NLRP3 activation

Previous studies have suggested that pyroptosis may play an important role in LPS-induced acute lung injury (ALI), but the exact mechanism of pyroptosis induction and the role of Angiotensin-converting enzyme 2 (ACE2)/Ang (1–7)/Mas axis in pyroptosis has not been investigated yet. The present study aimed to establish a mice model of ALI and clarify the involvement of pyroptosis and ACE2/Ang (1–7)/Mas axis. The results showed that LPS induced pyroptosis in lung, demonstrated by increased expression of Gasdermin D (GSDMD), cleaved GSDMD, IL-1β, and Caspase-1. Treatment of Ang (1–7) significantly reduced the severity of ALI and pyroptosis, while AngII significantly exaggerated them. Furthermore, ACE2 activator resorcinolnaphthalein (RES) significantly reduced the severity of ALI and pyroptosis, but ACE2 inhibitor MLN-4760 and Mas inhibitor A779 significantly exaggerated them, suggesting that the ACE2/Ang (1–7)/Mas axis was involved in the pyroptosis in LPS-induced ALI. In addition, Ang (1–7) and RES significantly decreased the levels of NLRP3, which were increased by AngII and A779. NLRP3 knockout significantly reduced the severity of ALI and pyroptosis. In conclusion, pyroptosis played an important role in ALI induced by LPS. The ACE2/Ang (1–7)/Mas axis negatively regulated the pyroptosis and protected mice against LPS-induced ALI through NLRP3 inhibition. The present study expanded our understating of the role of ACE2/Ang (1–7)/Mas axis in ALI by providing a novel explanation that it may regulate the pyroptosis in ALI.

The abnormalities of coagulation and fibrinolysis in acute lung injury caused by gas explosion.

Acute lung injury (ALI) caused by gas explosion is common, and warrants research on the underlying mechanisms. Specifically, the role of abnormalities of coagulation and fibrinolysis in this process has not been defined. It was hypothesized that the abnormal coagulation and fibrinolysis promoted ALI caused by gas explosion. Based on the presence of ALI, 74 cases of gas explosion injury were divided into the ALI and non-ALI groups. The results of prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen (FIB), and platelet count (PLT) were collected within 24 hours and compared between the groups. ALI models caused by gas explosion were established in Sprague Dawley rats, and injuries were evaluated using hematoxylin and eosin (HE) staining and histopathological scoring. Moreover, the bronchoalveolar lavage fluid (BALF) was collected to examine thrombin-antithrombin complex (TAT), tissue factor (TF), tissue factor pathway inhibitor (TFPI), and plasminogen activator inhibitor-1 (PAI-1) levels by enzyme-linked immunosorbent assay (ELISA). The patients in ALI group had shorter PT and longer APTT, raised concentration of FIB and decreased number of PLT, as compared to the non-ALI group. In ALI rats, the HE staining revealed red blood cells in alveoli and interstitial thickening within 2 hours which peaked at 72 hours. The levels of TAT/TF in the BALF increased continually until the seventh day, while the PAI-1 was raised after 24 hours and 7 days. The TFPI was elevated after 2 hours and 24 hours, and then decreased after 72 hours. Abnormalities in coagulation and fibrinolysis in lung tissues play a role in ALI caused by gas explosion.

Topiroxostat ameliorates oxidative stress and inflammation in sepsis-induced lung injury.

Sepsis-induced lung injury was the most common cause of death in patients. Topiroxostat, a novel xanthine oxidoreductase inhibitors, possessed obvious organ protectives effects. Xanthine oxidase played a vital role in acute lung injury. The study aimed to investigate the roles of Topiroxostat in sepsis-induced lung injury. The sepsis rats were established using cecum ligation and perforation. The lung damage induced by sepsis was evaluated by Hematoxylin and Eosin staining and lung tissue wet to dry ratio. The oxidative stress was detected by measurement of reactive oxygen species, malondialdehyde, myeloperoxidase and superoxide dismutase (SOD). The pro-inflammatory mediators, tumor necrosis factor-α, interleukin (IL)-1β, IL-6 and monocyte chemotactic protein 1, were measured by Enzyme-Linked Immunosorbent Assay. The cell apoptosis in lung was detected by TUNNEL staining and western blot analysis of apoptosis-related proteins including pro-apoptosis proteins, Bax, cleaved caspase9, cleaved caspase3 and anti-apoptosis protein Bcl2. The results showed that Topiroxostat significantly reduced lung damage, along with decreased oxidative stress, inflammation response and apoptosis in sepsis rats. Topiroxostat exerted markedly protective effects in sepsis-induced lung injury and could be an antioxidant in treating sepsis-induced lung injury.

Curcumin Promotes the Expression of IL-35 by Regulating Regulatory T Cell Differentiation and Restrains Uncontrolled Inflammation and Lung Injury in Mice.

Interleukin (IL)-35, which has an anti-inflammatory role in acute respiratory distress syndrome (ARDS)/acute lung injury (ALI), is relatively promising as a drug target. Studies have shown that curcumin may play a therapeutic role in ALI and enhance the suppressive function of regulatory T cells (Tregs). To illustrate the effect of curcumin on the regulation of Treg cell differentiation and expression of IL-35, we built a cecal ligation and puncture (CLP)-induced acute lung injury mouse mode with curcumin pretreatment. The expression of IL-35 in serum, severity of lung injury, IL-17A in lung tissue, survival rate, Treg-related cytokines levels in serum, nuclear factor-kappa B (NF-κB)'s nuclear translocation in lung tissue, and splenic CD4+CD25+FOXP3+ Tregs were assessed. Furthermore, the proportion of Tregs, STAT5, and IL-35 expression during naïve CD4+ T cell differentiation in vitro was measured. Compared with the CLP group, the increased IL-35 expression in CLP with the curcumin pretreatment (CLP + Cur) group was consistent with the decreased severity of lung injury, IL-17A protein levels in lung tissue, and Treg-related cytokines levels. Pretreatment with curcumin, the survival rate climbed to 50%, while the mortality rate was 100% in the CLP group. In addition, splenic CD4+CD25+FOXP3+ Treg cells increased in the CLP + Cur group. In vitro, CD4+CD25+FOXP3+ Treg cells from naïve CD4+ T cells, STAT5 proportion, and IL-35 expression increased after curcumin treatment. These findings showed that curcumin might regulate IL-35 by activating the differentiation of Treg cells to control the inflammation in acute lung injury.

Progranulin Improves Acute Lung Injury through Regulating the Differentiation of Regulatory T Cells and Interleukin-10 Immunomodulation to Promote Macrophage Polarization.

Progranulin (PGRN), which plays an anti-inflammatory role in acute lung injury (ALI), is promising as a potential drug. Studies have shown that regulatory T cells (Tregs) and interleukin- (IL-) 10 can repress inflammation and alleviate tissue damage during ALI. In this study, we built a lipopolysaccharide- (LPS-) induced ALI mouse model to illustrate the effect of PGRN on regulation of Treg differentiation and modulation of IL-10 promoting macrophage polarization. We found that the proportion of Tregs in splenic mononuclear cells and peripheral blood mononuclear cells was higher after treatment with PGRN. The increased proportion of Tregs after PGRN intratracheal instillation was consistent with the decreased severity of lung injury, the reduction of proinflammatory cytokines, and the increase of anti-inflammatory cytokines. In vitro, the percentages of CD4+CD25+FOXP3+ Tregs from splenic naïve CD4+ T cells increased after PGRN treatment. In further research, it was found that PGRN can regulate the anti-inflammatory factor IL-10 and affect the polarization of M1/M2 macrophages by upregulating IL-10. These findings show that PGRN likely plays a protective role in ALI by promoting Treg differentiation and activating IL-10 immunomodulation.

Unraveling the role of β2 integrins in neutrophil migration to the lung and subsequent acute lung injury in sepsis

Abstract Sepsis is the leading cause of death in intensive care units but not specific therapy is yet available. Acute lung injury (ALI) is a major complication in sepsis, resulting from massive migration of neutrophils to the lung, but the exact mechanism is not known. β2 (CD18) integrin family [consisting of αLβ2 (CD11a/CD18), αMβ2 (CD11b/CD18), αXβ2 (CD11c/CD18) and αDβ2 (CD11d/CD18)] and its counter-receptor on the endothelium, ICAM-1 (CD54), are critical for neutrophil migration, but their role in ALI is not yet delineated. Using a murine model of sepsis induced by cecal ligation and puncture (CLP) surgery, we showed decreased neutrophil levels and attenuated injury in the lung of β2−/− and ICAM-1−/−mice at 12h post-CLP, suggesting the importance of β2 integrins in this process. In addition, we observed decreased neutrophil levels and attenuated injury in the lung of αDβ2−/− mice but not in the lung of αLβ2−/− and αMβ2−/− mice, suggesting that among β2 integrins, αDβ2 has an orchestrating role in neutrophil migration to the lung and subsequent ALI in sepsis. In support, we found increased αDβ2 expression levels on neutrophils in the lung and blood of WT mice as sepsis progressed. RNAseq analysis in neutrophils from blood and lung of WT and αDβ2−/− mice showed that αDβ2 mediates neutrophil migration to the lung through pathways associated with antigen representation, maturation, apoptosis and NOD-like receptor signaling. αDβ2−/− neutrophils had also less Cxcr2, Ltb4r1 and Dhrs9 expression, associated with neutrophil migration and the retinoic acid pathway. Together, our results suggest a mechanism for neutrophil migration to the lung and subsequent ALI in sepsis in which αDβ2 has a major role and could be a novel target for therapeutic intervention.

Vascular permeability in the fibrotic lung.

Idiopathic pulmonary fibrosis (IPF) is thought to result from aberrant tissue repair processes in response to chronic or repetitive lung injury. The origin and nature of the injury, as well as its cellular and molecular targets, are likely heterogeneous, which complicates accurate pre-clinical modelling of the disease and makes therapeutic targeting a challenge. Efforts are underway to identify central pathways in fibrogenesis which may allow targeting of aberrant repair processes regardless of the initial injury stimulus. Dysregulated endothelial permeability and vascular leak have long been studied for their role in acute lung injury and repair. Evidence that these processes are of importance to the pathogenesis of fibrotic lung disease is growing. Endothelial permeability is increased in non-fibrosing lung diseases, but it resolves in a self-limited fashion in conditions such as bacterial pneumonia and acute respiratory distress syndrome. In progressive fibrosing diseases such as IPF, permeability appears to persist, however, and may also predict mortality. In this hypothesis-generating review, we summarise available data on the role of endothelial permeability in IPF and focus on the deleterious consequences of sustained endothelial hyperpermeability in response to and during pulmonary inflammation and fibrosis. We propose that persistent permeability and vascular leak in the lung have the potential to establish and amplify the pro-fibrotic environment. Therapeutic interventions aimed at recognising and "plugging" the leak may therefore be of significant benefit for preventing the transition from lung injury to fibrosis and should be areas for future research.

Coronavirus Disease 2019 (COVID-19) and Cardiovascular Disease: A Viewpoint on the Potential Influence of Angiotensin-Converting Enzyme Inhibitors/Angiotensin Receptor Blockers on Onset and Severity of Severe Acute Respiratory Syndrome Coronavirus 2 Infection.

Coronavirus Disease 2019 (COVID-19) and Cardiovascular Disease: A Viewpoint on the Potential Influence of Angiotensin-Converting Enzyme Inhibitors/Angiotensin Receptor Blockers on Onset and Severity of Severe Acute Respiratory Syndrome Coronavirus 2 Infection.

ZJ01, a Small Molecule Inhibitor of the Kelch-Like ECH-Associated Protein 1-Nuclear Factor Erythroid 2-Related Factor 2 (Keap1-Nrf2) Protein-Protein Interaction, Reduces Hyperoxic Acute Lung Injury in a Mouse Model.

BackgroundHyperoxic acute lung injury (ALI) is a complication of ventilation in patients with respiratory failure. Nuclear factor erythroid-2-related factor 2 (Nrf2) has an important role in ALI. Kelch-like ECH-associated protein 1 (Keap1) binds to Nrf2. ZJ01 is a small molecule inhibitor of Keap1-Nrf2 protein-protein interaction (PPI) that can reduce Keap1-induced inhibition of Nrf2. This study aimed to investigate the effects of ZJ01 and the heme oxygenase-1 (HO-1) inhibitor, zinc protoporphyrin IX (ZnPP IX), in a mouse model of hyperoxic ALI.Material/MethodsC57BL/6J mice included five study groups: the room air+vehicle-treated group; the room air+ZJ01 group; the hyperoxia+vehicle-treated group; the hyperoxia+ZJ01 group; and the hyperoxia+ZJ01+ZnPP IX group. ZJ01, ZnPP IX, or vehicle were given 1 h after the hyperoxia challenge. The lungs from the mice were harvested at 72 h following the hyperoxia challenge.ResultsHyperoxia exposure for 72 h increased the activity of myeloperoxidase, the lung water content, the levels of tumor necrosis factor-α (TNF-α), and matrix metalloprotease-9 (MMP-9) in the vehicle-treated mice. ZJ01 treatment reduced hyperoxia-induced inflammation and increased the activation of Nrf2 and HO-1 compared with the vehicle-treated mice. Histology of the lungs showed that ZJ01 treatment reduced the changes of hyperoxia-induced ALI. Pretreatment with ZnPP IX reversed the beneficial effect of ZJ01.ConclusionsZJ01, a Keap1-Nrf2 PPI inhibitor, reduced hyperoxic ALI in a mouse model through the Nrf2/HO-1 pathway.

Effect of human placental mesenchymal stem cells transplantation on pulmonary vascular endothelial permeability and lung injury repair in mice with acute lung injury

To investigate the effects of human placental mesenchymal stem cells (hPMSCs) transplantation on pulmonary vascular endothelial permeability and lung injury repair in mice with lipopolysaccharide (LPS)-induced acute lung injury (ALI). The hPMSCs were isolated from the human placental tissue by enzyme digestion and passaged. The cell phenotype of the 3rd generation hPMSCs was detected by flow cytometry. Twenty-four 6-week-old healthy male C57BL/6 mice were randomly divided into 3 groups ( n=8). The mice were instilled with LPS in the airway to prepare an ALI model in the ALI model group and the hPMSCs treatment group, and with saline in the control group. At 12 hours after LPS infusion, the mice were injected with 3rd generation hPMSCs via the tail vein in hPMSCs treatment group and with saline in the ALI model group and the control group. At 24 hours after injection, the lung tissues of all mice were taken. The pathological changes were observed by HE staining. The wet/dry mass ratio (W/D) of lung tissue was measured. The Evans blue leak test was used to detect the pulmonary vascular endothelial permea bility in mice. The expression of lung tissue permeability-related protein (VE-cadherin) was detected by Western blot. Flow cytometry examination showed that the isolated cells had typical MSCs phenotypic characteristics. Mice in each group survived. The alveolar structure of the ALI model group significantly collapsed, a large number of inflammatory cells infiltrated, and local alveolar hemorrhage occurred; while the alveolar structure collapse of the hPMSCs treatment group significantly improved, inflammatory cells infiltration significantly reduced, and a few red blood cells were in the interstitial lung. W/D and exudation volume of Evans blue stain were significantly higher in the ALI model group than in the control group and the hPMSCs treatment group ( P<0.05), in the hPMSCs treatment group than in the control group ( P<0.05). The relative protein expression of VE-cadherin was significantly lower in the ALI model group than in the control group and the hPMSCs treatment group ( P<0.05), and in the hPMSCs treatment group than in the control group ( P<0.05). Intravenous injection of hPMSCs can effectively reduce the increased pulmonary vascular endothelial permeability mediated by LPS, relieve the degree of lung tissue damage, and play a therapeutic role in ALI mice.

Sevoflurane reduces inflammatory factor expression, increases viability and inhibits apoptosis of lung cells in acute lung injury by microRNA-34a-3p upregulation and STAT1 downregulation

ObjectiveEvidence has shown that sevoflurane plays a protective role in acute lung injury (ALI) due to its anti-inflammatory and apoptotic-regulating activity. Nevertheless, the mechanism of sevoflurane is still not completely understood. This study intends to discuss the mechanism of sevoflurane on ALI and the possible mechanisms involved. MethodsALI model of rats was established through intravenous injection of endotoxin lipopolysaccharide. microRNA-34a-3p (miR-34a-3p) and signal transducers and activators of transcription 1 (STAT1) expression in lung tissues of ALI rats were detected. The optimal inhaled concentration of sevoflurane was screened, and then the modeled rats were injected with miR-34a-3p inhibitors, overexpressed STAT1 and inhaled 1.0 Minimum Alveolar Concentration (MAC) sevoflurane to determine mean arterial pressure (MAP) of rats, wet weight/dry weight ratio and myeloperoxidase (MPO) activity, oxidative stress- and inflammation-related factors in lung tissues of rats, along with lung cell viability and apoptosis. ResultsMiR-34a-3p was downregulated while STAT1 was upregulated in ALI rats. Sevoflurane of 1.0 MAC was selected as the optimal inhalation concentration. Sevoflurane (1.0 MAC) increased MAP at T3 and reduced MPO activity, alleviated pathological damage, suppressed apoptosis, oxidative stress and inflammation, and induced cell viability in lung tissues of ALI rats. Down-regulated miR-34a-3p or up-regulated STAT reversed the functions of sevoflurane (1.0 MAC) on ALI rats. ConclusionCollectively, we demonstrate that sevoflurane reduces inflammatory factor expression, increases lung cell viability and inhibits lung cell apoptosis in ALI through upregulation of miR-34a-3p and downregulation of STAT1, which provides new clues for ALI treatment.

Interleukin‑35 reduces inflammation in acute lung injury through inhibiting TLR4/NF‑κB signaling pathways

Acute lung injury (ALI) in children is a complex disease that is accompanied by an inflammatory response. The pathogenesis of ALI in children is not yet well understood. Mice with ALI exhibit inflammation of the lungs and decreased expression of interleukin (IL)-35. To investigate whether the function of IL-35 affects lipopolysaccharide (LPS)-induced ALI, IL-35 was overexpressed in cells. Enzyme-linked immunosorbent assays indicated decreased levels of IL-6 and tumor necrosis factor-α in LPS-induced and agomir-IL-35-treated murine RAW264.7 macrophages. Finally, toll-like receptor 4 (TLR4)/NF-κB signaling pathways were analyzed. The expression of TLR4, NF-κB p65 and NF-κB p50 were decreased, as was the degradation of NF-κB inhibitor-α, in LPS-induced and agomir-IL-35-treated murine RAW264.7 macrophages. The results of the present study demonstrated that IL-35 may exhibit a protective role in ALI by modulating the TLR4/NF-κB signaling pathways.

A COX-2/sEH dual inhibitor PTUPB alleviates lipopolysaccharide-induced acute lung injury in mice by inhibiting NLRP3 inflammasome activation.

Rationale: Dysregulation of arachidonic acid (ARA) metabolism results in inflammation; however, its role in acute lung injury (ALI) remains elusive. In this study, we addressed the role of dysregulated ARA metabolism in cytochromes P450 (CYPs) /cyclooxygenase-2 (COX-2) pathways in the pathogenesis of lipopolysaccharide (LPS)-induced ALI in mice.Methods: The metabolism of CYPs/COX-2-derived ARA in the lungs of LPS-induced ALI was investigated in C57BL/6 mice. The COX-2/sEH dual inhibitor PTUPB was used to establish the function of CYPs/COX-2 dysregulation in ALI. Primary murine macrophages were used to evaluate the underlying mechanism of PTUPB involved in the activation of NLRP3 inflammasome in vitro.Results: Dysregulation of CYPs/COX-2 metabolism of ARA occurred in the lungs and in primary macrophages under the LPS challenge. Decrease mRNA expression of Cyp2j9, Cyp2j6, and Cyp2j5 was observed, which metabolize ARA into epoxyeicosatrienoic acids (EETs). The expressions of COX-2 and soluble epoxide hydrolase (sEH), on the other hand, was significantly upregulated. Pre-treatment with the dual COX-2 and sEH inhibitor, PTUPB, attenuated the pathological injury of lung tissues and reduced the infiltration of inflammatory cells. Furthermore, PTUPB decreased the pro-inflammatory factors, oxidative stress, and activation of NACHT, LRR, and PYD domains-containing protein 3 (NLRP3) inflammasome in LPS-induced ALI mice. PTUPB pre-treatment remarkably reduced the activation of macrophages and NLRP3 inflammasome in vitro. Significantly, both preventive and therapeutic treatment with PTUPB improved the survival rate of mice receiving a lethal dose of LPS.Conclusion: The dysregulation of CYPs/COX-2 metabolized ARA contributes to the uncontrolled inflammatory response in ALI. The dual COX-2 and sEH inhibitor PTUPB exerts anti-inflammatory effects in treating ALI by inhibiting the NLRP3 inflammasome activation.

ACE 2 in the Context of COVID 19 – An Opportunity for us or the Virus

ACE 2 acts a receptor for Spike S1 protein of SARS CoV 2. It has a protective role in acute lung injury and ARDS. Being a rate limiting factor in the pathogenesis of COVID 19 it can offers multiple avenues for therapeutic measures. The soluble form of ACE 2 if we can give in an inhaler or nebulised form can act as a competitive agent for viral binding in the lungs thus somewhat sparing the trans membrane ACE 2 from viral attack. An antibody directed against the ACE 2 receptor can have the same effect. As the human corona virus NL63 also binds to ACE 2 receptor in the same region as SARS CoV. Therefore co-infection with NL63 can be a disease modifier as NL63 causes mild disease in most of the cases. Also a potent selective inhibitor of ACE 2 can also be tested as a therapeutic option.

Mechanistic target of rapamycin-mediated autophagy is involved in the alleviation of lipopolysaccharide-induced acute lung injury in rats

Acute lung injury (ALI) is a complex clinical syndrome with high morbidity and mortality rates. Autophagy is an adaptive process that plays a complex role in ALI. The aim of this study was to investigate the effects of autophagy on lipopolysaccharide (LPS)-induced lung injury by establishing a rat ALI model and to further explore the possible mechanisms involved. Rats were pretreated with the autophagy inhibitor 3-methyladenine (3-MA) or the autophagy activator rapamycin before they were challenged with the intratracheal instillation of LPS (5 mg/kg). The level of autophagy in the lung tissue was detected. Lung injury and vascular permeability were assessed. The role of the mechanistic target of rapamycin (mTOR)-mediated Unc-51-like kinase 1 (ULK1) and the class III PI3 kinase VPS34 in autophagy regulation was examined. LPS challenge induced autophagy and rapamycin pretreatment enhanced autophagy activity in LPS-induced ALI rats. LPS caused severe lung injury and high pulmonary vascular permeability, which could be alleviated by enhancing autophagy. In addition, the inhibition of mTOR upregulated the expression of ULK1 and VPS34 and thus increased LPS-induced autophagy. Autophagy plays a protective role in LPS-induced ALI, and enhancing autophagy via the inhibition of mTOR alleviates lung injury and pulmonary barrier function. Moreover, mTOR negatively mediates ULK1 and VPS34 to regulate LPS-induced autophagy in rats.

Anti-IFN-γ therapy alleviates acute lung injury induced by severe influenza A (H1N1) pdm09 infection in mice.

Severe infection with influenza A (H1N1)pdm09 virus is characterized by acute lung injury. The limited efficacy of anti-viral drugs indicates an urgent need for additional therapies. We have previously reported that neutralization of gamma interferon (IFN-γ) could significantly rescue the thymic atrophy induced by severe influenza A (H1N1)pdm09 infection in BALB/c mice. A deeper investigation was conducted into the influence of neutralizing IFN-γ to the BALB/c mice weight, survival rate, and lung injury. The BALB/c mice was infected with severe influenza A (H1N1)pdm09. Monoclonal antibodies against IFN-γ were injected into the abdominal cavities of the mice. After neutralization of IFN-γ occurred in mice infected by severe ∖ influenza A (H1N1)pdm09, observing the influence of neutralizing IFN-γ to the BALB/c mice weight, survival rate, lung injury. Our results here showed that anti-IFN-γ therapy alleviated the acute lung injury in this mouse model. Neutralization of IFN-γ led to a significant reduction in the lung microvascular leak and the cellular infiltrate in the lung tissue, and also improved the outcome in mice mortality. Several pro-inflammatory cytokines, including interleukin (IL)-1α, tumor necrosis factor (TNF)-α and granulocyte-colony stimulating factor (G-CSF) in the bronchoalveolar lavage fluid (BALF), and the chemokines including G-CSF, monocyte chemoattractant protein-1 (MCP-1) in serum samples were found to be significantly reduced after anti-IFN-γ treatment. These results suggested that IFN-γ plays an important role in acute lung injury induced by severe influenza A (H1N1)pdm09 infection, and monoclonal antibodies against IFN-γ could be useful as a potential therapeutic remedy for future influenza pandemics.

Metformin Activates the Protective Effects of the AMPK Pathway in Acute Lung Injury Caused by Paraquat Poisoning.

Objective To observe whether metformin (MET) plays a protective role in acute lung injury (ALI) induced by paraquat (PQ) poisoning in rats by activating the AMPK/NF-κB signaling pathway. Methods PQ exposure was used to construct a rat model of ALI and a model of acute type II alveolar epithelial cell (RLE-6TN) injury, and MET intervention was performed. Rat lung tissue samples were collected to evaluate pathological changes in rat lung tissue, the oxidation index, and inflammatory factors; cell viability was detected by CCK-8 assays, and the protein expression levels of phospho-AMPK and phospho-NF-κBp65 in rat lung tissue and RLE-6TN cells were observed by Western blotting. Results Compared with the PQ group, the MET treatment group showed significantly (1) reduced lung wet/dry ratio (W/D: 4.67 ± 0.31 vs. 5.45 ± 0.40, P < 0.001), (2) reduced pathological changes in lung tissue, (3) decreased MDA levels (nmol/mg prot: 2.70 ± 0.19 vs. 3.08 ± 0.15, P < 0.001) and increased SOD and GSH-Px activities (U/mg prot: 76.17 ± 5.22 vs. 45.23 ± 6.58, 30.40 ± 2.84 vs. 21.00 ± 3.20; all P < 0.001) in lung tissue homogenate, (4) reduced levels of IL-1β, IL-6, and TNF-α in lung tissue homogenates (pg/mL: 47.87 ± 5.06 vs. 66.77 ± 6.55; 93.03 ± 7.41 vs. 107.39 ± 9.81; 75.73 ± 6.08 vs. 89.12 ± 8.94; all P < 0.001), (5) increased activity of RLE-6TN cells (%: 0.69 ± 0.09, 0.76 ± 0.06, and 0.58 ± 0.03 vs. 0.50 ± 0.05; all P < 0.05), (6) decreased protein levels of phospho-NF-κBp65 in lung homogenates and RLE-6TN cells (p-NF-κB/NF-κB: 0.47 ± 0.09 vs. 0.81 ± 0.13; 0.26 ± 0.07 vs. 0.79 ± 0.13; all P < 0.01), and (7) upregulated protein expression of phospho-AMPK in lung homogenates and RLE-6TN cells (p-AMPK/AMPK: 0.88 ± 0.05 vs. 0.36 ± 0.12; 0.93 ± 0.03 vs. 0.56 ± 0.15; all P < 0.01). After the addition of the AMPK inhibitor Compound C (Com C), the protein expression levels of phospho-AMPK and phospho-NF-κBp65 returned to baseline. Conclusion MET can effectively alleviate ALI induced by paraquat poisoning and increase the viability of cells exposed to paraquat. The mechanism may be related to the activation of the AMPK/NF-κB pathway, downregulation of inflammatory mediators such as IL-6 and TNF-α, and upregulation of the SOD and GSH-Px oxidation index, and these effects can be inhibited by the AMPK inhibitor Com C.