Abstract Acute Lung Injury Research Articles

Soy isoflavone reduces LPS-induced acute lung injury via increasing aquaporin 1 and aquaporin 5 in rats.

Acute lung injury (ALI) followed with severe inflammation and oxidative stress. Anti-inflammatory and antioxidant are the properties of aquaporin 1 (AQP1) and aquaporin 5 (AQP5). The goal of this study was to see if soy isoflavone can diminish lipopolysaccharide (LPS)-induced ALI and the underling mechanism. LPS-induced ALI was given to Sprague-Dawley rats 14 days following oophorectomy. One hour before the LPS challenge, estradiol (1 mg/kg) was administered subcutaneously as positive control and soy isoflavone was intragastric administration for 14 days prior to LPS challenge with different doses. Six hours after LPS challenge, the pulmonary edema, pathophysiology, inflammation, and the oxidative stress in lung tissues of rats were discovered. We found that soy isoflavone can reduce pulmonary edema and the lung pathology in a dose-dependent manner. Furthermore, tumor necrosis factor-alpha, interleukin-1β, and interleukin-6 were decreased in rats treated with soy isoflavone. Meanwhile, soy isoflavone reduced pulmonary oxidative stress by decreasing malondialdehyde levels, while increasing superoxide dismutase levels in lung tissues in a dose-dependent manner. Mechanically, we found that the mRNA and protein level of AQP1 and AOP5 were increased in lung tissues of rats treated with soy isoflavone compared the LPS-treated rats. Thus, soy isoflavone alleviates LPS-induced ALI through inducing AQP1 and AQP5.

Prostaglandin D2 Attenuates Lipopolysaccharide-Induced Acute Lung Injury through the Modulation of Inflammation and Macrophage Polarization

Acute lung injury (ALI) is a well-known respiratory disease and a leading cause of death worldwide. Despite advancements in the medical field, developing complete treatment strategies against this disease is still a challenge. In the current study, the therapeutic role of prostaglandin D2 (PGD2) was investigated on lipopolysaccharide (LPS)-induced lung injury in mice models and RAW264.7 macrophages through anti-inflammatory, histopathology, immunohistochemistry, and TUNEL staining. The overproduction of cytokines by RAW264.7 macrophages was observed after stimulation with LPS. However, pretreatment with PGD2 decreased the production of cytokines. The level of inflammatory markers was significantly restored in the PGD2 treatment group (TNF-α = 58.6 vs. 78.5 pg/mL; IL-1β = 29.3 vs. 36.6 pg/mL; IL-6 = 75.4 vs. 98.2 pg/mL; and CRP = 0.84 vs. 1.14 ng/mL). The wet/dry weight ratio of the lungs was quite significant in the disease control (LPS-only treatment) group. Moreover, the histological changes as determined by haematoxylin and eosin (H&E) staining clearly showed that PGD2 treatment maintains the lung tissue architecture. The iNOS expression pattern was increased in lung tissues of LPS-treated animals, whereas, in mice treated with PGD2, the expression of iNOS protein decreased. Flow cytometry data demonstrated that LPS intoxication enhanced apoptosis, which significantly decreased with PGD2 treatment. In conclusion, all these observations indicate that PGD2 provides an anti-inflammatory response in RAW264.7 macrophages and in ALI, and they suggest a therapeutic potential in lung pathogenesis.

Potential biomarkers for inflammatory response in acute lung injury

Acute lung injury (ALI) is a severe respiratory disorder occurring in critical care medicine, with high rates of mortality and morbidity. This study aims to screen the potential biomarkers for ALI.Microarray data of lung tissues from lung-specific geranylgeranyl pyrophosphate synthase large subunit 1 knockout and wild-type mice treated with lipopolysaccharide were downloaded. Differentially expressed genes (DEGs) between ALI and wild-type mice were screened. Functional analysis and the protein–protein interaction (PPI) modules were analyzed. Finally, a miRNA-transcription factor (TF)-target regulation network was constructed.Totally, 421 DEGs between ALI and wild-type mice were identified. The upregulated DEGs were mainly enriched in the peroxisome proliferator-activated receptor signaling pathway, and fatty acid metabolic process, while downregulated DEGs were related to cytokine–cytokine receptor interaction and regulation of cytokine production. Cxcl5, Cxcl9, Ccr5, and Cxcr4 were key nodes in the PPI network. In addition, three miRNAs (miR505, miR23A, and miR23B) and three TFs (PU1, CEBPA, and CEBPB) were key molecules in the miRNA-TF-target network. Nine genes including ADRA2A, P2RY12, ADORA1, CXCR1, and CXCR4 were predicted as potential druggable genes.As a conclusion, ADRA2A, P2RY12, ADORA1, CXCL5, CXCL9, CXCR1, and CXCR4 might be novel markers and potential druggable genes in ALI by regulating inflammatory response.

The Reaction Pathway of miR-30c-5p Activates Lipopolysaccharide Promoting the Course of Traumatic and Hemorrhagic Shock Acute Lung Injury.

Acute lung injury (ALI) is an acute hypoxic respiratory failure caused by diffuse inflammatory injury in alveolar epithelial cells during severe infection, trauma, and shock. Among them, trauma/hemorrhagic shock (T/HS) is the main type of indirect lung injury. Despite a great number of clinical studies, indirect factor trauma/hemorrhagic shock to the function and the mechanism in acute lung injury is not clear yet. Therefore, it is still necessary to carry on relevant analysis in order to thoroughly explore its molecular and cellular mechanisms and the pathway of disease function. In our research, we aimed to identify potential pathogenic genes and do modular analysis by downloading disease-related gene expression profile data. And our dataset is from the NCBI-GEO database. Then, we used the Clusterprofiler R package, GO function, and KEGG pathway enrichment analysis to analyze the core module genes. In addition, we also identified key transcription factors and noncoding RNAs. Based on the high degree of interaction of potential pathogenic genes and their involved functions and pathways, we identified 17 dysfunction modules. Among them, up to 9 modules significantly regulate the response to bacterial-derived molecules, and the response to lipopolysaccharide and other related functional pathways that mediate disease development. In addition, miR-290, miR-30c-5p, miR-195-5p, and miR-1-3p-based ncRNA and Jun, Atf1, and Atf3-based transcription factors have a total of 80 transcription drivers for functional modules. In summary, this study confirmed that miR-30c-5p activates lipopolysaccharide response pathway to promote the pathogenesis of ALI induced by hemorrhagic shock. This result can be an important direction for further research on related deepening diseases such as acute respiratory distress syndrome (ARDS). It further provides a piece of scientific medical evidence for revealing the pathogenic principle and cure difficulty of acute lung injury and also provides important guidance for the design of therapeutic strategies and drug development.

Role of miR-584-5p in Lipopolysaccharide-Stimulated Human Bronchial Epithelial Cell Inflammation and Apoptosis.

Acute lung injury (ALI)/acute respiratory distress syndrome is a common clinical syndrome characterized by respiratory failure. MicroRNAs (miRNAs) are closely related to ALI and acute respiratory distress syndrome. TargetScan software analysis showed that miR-584-5p can bind to the 3ʹ noncoding region of TLR4, which is involved in the occurrence and development of ALI, thereby affecting the inflammatory pathway and inflammation development. Thus, we aimed to determine whether miR-584-5p affects ALI. Human bronchial epithelial (16-HBE) cells were transfected with miR-584-5p mimics or inhibitors and then stimulated with lipopolysaccharide (LPS).The cell viability, apoptosis, release of proinflammatory factors, mTOR, and NF-κB pathway protein expression were evaluated respectively. Mimic584 increased, whereas inhibitor584 decreased, LPS-stimulated inflammation. The protein expression of inflammatory factors was significantly increased in 16-HBE cells in the mimic584 + LPS group and decreased in the inhibitor584 + LPS group. Mimic584 activated mTOR and the NF-κB-related proteins P65 and p-p65, whereas inhibitor584 inactivated the proteins in 16-HBE cells. Overexpression of miR-584 significantly promoted apoptosis in LPS-stimulated 16-HBE cells. There were no differences in the proliferation and cell cycle of LPS-stimulated 16-HBE cells regardless of mimic584 or inhibitor584 transfection. Collectively, we demonstrated that inhibitor584 can alleviate ALI-induced expression of inflammatory factors via mTOR signaling and the NF-κB pathway. In conclusion, we found that inhibitor584 transfection could be a potential therapeutic strategy for ALI.

BMI1 Silencing Induces Mitochondrial Dysfunction in Lung Epithelial Cells Exposed to Hyperoxia.

Acute Lung Injury (ALI), characterized by bilateral pulmonary infiltrates that restrict gas exchange, leads to respiratory failure. It is caused by an innate immune response with white blood cell infiltration of the lungs, release of cytokines, an increase in reactive oxygen species (ROS), oxidative stress, and changes in mitochondrial function. Mitochondrial alterations, changes in respiration, ATP production and the unbalancing fusion and fission processes are key events in ALI pathogenesis and increase mitophagy. Research indicates that BMI1 (B cell-specific Moloney murine leukemia virus integration site 1), a protein of the Polycomb repressive complex 1, is a cell cycle and survival regulator that plays a role in mitochondrial function. BMI1-silenced cultured lung epithelial cells were exposed to hyperoxia to determine the role of BMI1 in mitochondrial metabolism. Its expression significantly decreases in human lung epithelial cells (H441) following hyperoxic insult, as determined by western blot, Qrt-PCR, and functional analysis. This decrease correlates with an increase in mitophagy proteins, PINK1, Parkin, and DJ1; an increase in the expression of tumor suppressor PTEN; changes in the expression of mitochondrial biomarkers; and decreases in the oxygen consumption rate (OCR) and tricarboxylic acid enzyme activity. Our bioinformatics analysis suggested that the BMI1 multifunctionality is determined by its high level of intrinsic disorder that defines the ability of this protein to bind to numerous cellular partners. These results demonstrate a close relationship between BMI1 expression and mitochondrial health in hyperoxia-induced acute lung injury (HALI) and indicate that BMI1 is a potential therapeutic target to treat ALI and Acute Respiratory Distress Syndrome.

Construction of a potential microRNA and messenger RNA regulatory network of acute lung injury in mice

Acute lung injury (ALI) is a life-threatening clinical condition associated with critically ill patients, and the construction of potential microRNA (miRNA) and messenger RNA (mRNA) regulatory networks will help to fully elucidate its underlying molecular mechanisms. First, we screened fifteen upregulated differentially expressed miRNAs (DE-miRNAs) and six downregulated DE-miRNAs from the Gene Expression Omnibus (GEO) database. Then, the predicted target genes of the upregulated and downregulated DE-miRNAs were identified from the miRNet database. Subsequently, differentially expressed mRNAs (DE-mRNAs) were identified from the GEO database and subjected to combined analysis with the predicted DE-miRNA target genes. Eleven target genes of the upregulated DE-miRNAs and one target gene of the downregulated DE-miRNAs were screened out. To further validate the prediction results, we randomly selected a dataset for subsequent analysis and found some accurate potential miRNA-mRNA regulatory axes, including mmu-mir-7b-5p-Gria1, mmu-mir-486a-5p-Shc4 and mmu-mir-486b-5p-Shc4 pairs. Finally, mir-7b and its target gene Gria1 and mir-486b and its target gene Shc4 were further validated in a bleomycin-induced ALI mouse model. We established a potential miRNA-mRNA regulatory network of ALI in mice, which may provide a basis for basic and clinical research on ALI and advance the available treatment options.

Long non-coding RNA LINC01194 promotes the inflammatory response and apoptosis of lipopolysaccharide-treated MLE-12 cells through the miR-203a-3p/MIP-2 axis.

Acute lung injury (ALI) induced by bacteria lipopolysaccharide (LPS) is characterized by the upregulation of the apoptosis rate of tissue cells and aggravation of inflammatory response. Although many studies have focused on the pathogenesis of this disease, its mechanism remains unknown. This study examined the regulatory role of long non-coding RNA (lncRNA) LINC01194 in the progression of ALI through various bioinformatics analyses and experimental work, including ELISA assay, dual-luciferase reporter assay, biotinylated RNA pull-down assay, and Western blot analysis. The result showed that the LINC01194 was overexpressed in the ALI-induced mice model. We observed a significant upregulation of LINC01194 in LPS-treated mouse lung epithelial type II cells (MLE-12 cells) after 24 h of induction. Bioinformatics analysis, ELISA assay, quantitative reverse transcription polymerase chain reaction analysis, biotinylated RNA pull-down assay, apoptosis test, and Western blot analysis demonstrated that the LINC01194 could act as a microRNA (miR) miR-203a-3p sponge to activate the inflammatory response in LPS-induced ALI model through post-transcriptional upregulation of macrophage inflammatory protein (MIP-2). We showed that LINC01194 regulates the inflammatory response and apoptosis of LPS-induced mice and MLE-12 cells via the miR-203a-3p/MIP-2 axis. LINC01194 could be a potential biomarker for early diagnosis and the treatment of ALI.

Peptide inhibition of acute lung injury in a novel two-hit rat model.

Acute lung injury (ALI) often causes severe trauma that may progress to significant morbidity and mortality. ALI results from a combination of the underlying clinical condition of the patient (e.g., inflammation) with a secondary insult such as viral pneumonia or a blood transfusion. While the secondary insult may be variable, the rapidly progressive disease process leading to pulmonary failure is typically mediated by an overwhelming innate immunological or inflammatory reaction driven by excessive complement and neutrophil-mediated inflammatory responses. We recently developed a ‘two-hit’ ALI rat model mediated by lipopolysaccharide followed by transfusion of incompatible human erythrocytes resulting in complement activation, neutrophil-mediated ALI and free DNA in the blood indicative of neutrophil extracellular trap formation. The objective of this study was to evaluate the role of peptide inhibitor of complement C1 (RLS-0071), a classical complement pathway inhibitor and neutrophil modulator in this animal model. Adolescent male Wistar rats were infused with lipopolysaccharide followed by transfusion of incompatible erythrocytes in the presence or absence of RLS-0071. Blood was collected at various time points to assess complement C5a levels, free DNA and cytokines in isolated plasma. Four hours following erythrocyte transfusion, lung tissue was recovered and assayed for ALI by histology. Compared to animals not receiving RLS-0071, lungs of animals treated with a single dose of RLS-0071 showed significant reduction in ALI as well as reduced levels of C5a, free DNA and inflammatory cytokines in the blood. These results demonstrate that RLS-0071 can modulate neutrophil-mediated ALI in this novel rat model.

Suppression of lncRNA NLRP3 inhibits NLRP3-triggered inflammatory responses in early acute lung injury

Acute lung injury (ALI) is a common lung pathology that is accompanied by alveolar macrophage (AM) activation and inflammatory response. This study investigated the role of the long non-coding RNA NONRATT004344 (hereafter named lncRNA NLRP3) in regulating the Nod-like receptor protein 3 (NLRP3)-triggered inflammatory response in early ALI and the underlying mechanism as well. We established LPS-induced ALI models to explore their interactive mechanisms in vitro and in vivo. Luciferase reporter assays were performed to determine that miR-138-5p could bind to lncRNA NLRP3 and NLRP3. We observed increased lncRNA NLRP3 expression, decreased miR-138-5p expression, NLRP3 inflammasome activation, and upregulated caspase-1, IL-1β, and IL-18 expression in the LPS-induced ALI model. Furthermore, lncRNA NLRP3 overexpression activated the NLRP3 inflammasome and promoted IL-1β and IL-18 secretion; the miR-138-5p mimic abolished these effects in vivo and in vitro. Consistently, miR-138-5p inhibition reversed the effects of lncRNA NLRP3 silencing on the expression of NLRP3-related molecules and inhibition of the NLRP3/caspase-1/IL-1β signalling pathway. Mechanistically, lncRNA NLRP3 sponging miR-138-5p facilitated NLRP3 activation through a competitive endogenous RNA (ceRNA) mechanism. In summary, our results suggested that lncRNA NLRP3 binding miR-138-5p promotes NLRP3-triggered inflammatory response via lncRNA NLRP3/miR-138-5p/NLRP3 ceRNA network (ceRNET) and provides insights into the treatment of early ALI.

Piper Kadsura Extract Inhibits miR-155 to Protect Lipopolysaccharide-Induced Acute Lung Injury

Acute lung injury (ALI) is a common and critical disease encountered in clinical practice. When the disease progresses to a more serious stage, it is called acute respiratory distress syndrome and is associated with a high mortality rate. However, there is a lack of specific drugs for treating this disease; therefore, it is very important to find safe and effective drugs for treatment. Piper kadsura (P. kadsura), part of the of the vin family Piperaceae, has a capability to dispel wind and dampness and its n-butanol extract can provide protection against inflammatory responses, such as inflammatory infiltration and hyperplasia of synovial tissue of joints. In order to explore the therapeutic effect of P. kadsura extract on ALI, we treated HPAEpiC cells with different doses of its extract. We found that after treatment using low-medium and high-dose P. kadsura extract, the optical density value was decreased in HPAEpiC cells as induced by lipopolysaccharide (LPS). In addition, the following were statistically and significantly decreased in a dose-dependent (P < 0.05): the apoptosis rate, cleaved-caspase3 expression, the expression levels of TNF-α, IL-6, and miR-155. However, procaspase 3 increased the expression of miR-155, which can promote LPS-induced apoptosis and the release of inflammatory factors in HPAEpiC cells. The overexpressed miR-155 can weaken the protection conferred by P. kadsura extract on ALI. These results suggest that P. kadsura extract may play a protective role against ALI induced by LPS by decreasing the expression of miR-155.

Resveratrol pretreatment mitigates LPS-induced acute lung injury by regulating conventional dendritic cells' maturation and function.

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is a severe syndrome lacking efficient therapy and resulting in high morbidity and mortality. Although resveratrol (RES), a natural phytoalexin, has been reported to protect the ALI by suppressing the inflammatory response, the detailed mechanism of how RES affected the immune system is poorly studied. Pulmonary conventional dendritic cells (cDCs) are critically involved in the pathogenesis of inflammatory lung diseases including ALI. In this study, we aimed to investigate the protective role of RES via pulmonary cDCs in lipopolysaccharide (LPS)-induced ALI mice. Murine ALI model was established by intratracheally challenging with 5 mg/kg LPS. We found that RES pretreatment could mitigate LPS-induced ALI. Additionally, proinflammatory-skewed cytokines decreased whereas anti-inflammatory-related cytokines increased in bronchoalveolar lavage fluid by RES pretreatment. Mechanistically, RES regulated pulmonary cDCs’ maturation and function, exhibiting lower level of CD80, CD86, major histocompatibility complex (MHC) II expression, and IL-10 secretion in ALI mice. Furthermore, RES modulated the balance between proinflammation and anti-inflammation of cDCs. Moreover, in vitro RES pretreatment regulated the maturation and function of bone marrow derived dendritic cells (BMDCs). Finally, the adoptive transfer of RES-pretreated BMDCs enhanced recovery of ALI. Thus, these data might further extend our understanding of a protective role of RES in regulating pulmonary cDCs against ALI.

Sodium houttuyfonate relieves acute lung injury by nano micellar carrier and inhibits mitogen-activated protein kinase and nuclear factor kappa-B activation in mice

Acute lung injury (ALI) is characterized by increased pulmonary vascular permeability in response to the accumulation of inflammatory cells, release of inflammatory cytokines, and activated oxidative stress. The present study was performed to investigate the effect of sodium houttuyfonate (SH), an extract of Houttuynia cordata, on inflammatory response and oxidative stress in ALI induced by lipopolysaccharides (LPS). Male C57BL/6 mice were randomly allocated to control, LPS, dimethyl sulfoxide (DMSO), and SH groups. The ALI model was established by intratracheal LPS injection. Lung tissue was collected 6 h after LPS injection for histopathological analysis, measurement of wet-to-dry ratio, myeloperoxidase (MPO) and oxidative stress levels, and the p38, jun N-terminal kinase (JNK), extracellular regulated kinase (ERK), and p65 phosphorylation levels. Bronchoalveolar fluid (BALF) was collected for the detection of protein concentration, MPO and cytokine levels. The histopathological test showed that SH significantly alleviates damage to pulmonary tissue. Improved vascular permeability was indicated by reduced BALF protein level and lung wet-to-dry ratio in the SH group. MPO levels were decreased in lung tissue and BALF. Oxidative stress and inflammatory responses were inhibited by SH, as indicated by MDA, SOD and cytokine levels. The MAPK and NF-KB pathways were inhibited as shown by the attenuated phosphorylation of p38, JNK, ERK and p65. Sodium houttuyfonate exhibited a protective role against LPS-induced lung injury through anti-oxidative and anti-inflammatory effects. The MAPK and NF-K B pathways may be inhibited by sodium houttuyfonate. Sodium Houttuynin has a good effect on a variety of acute infectious diseases, but its solubility and stability are insufficient, which limits its efficacy. Nano delivery system can enhance the effective ingredients of traditional Chinese medicine, reduce the toxic and side effects of drugs, and improve their medicinal properties. Therefore, this paper adopts nano delivery system to assist drug use and improve research efficiency.

Gut microbiota modulate susceptibility to bleomycin-induced lung injury.

Abstract Acute lung injury (ALI) resulting in acute respiratory distress syndrome (ARDS) affects almost 200,000 people in the US each year, leading to 75,000 deaths. Airway instillation of bleomycin (BLM) in mice is a widely used, yet challenging model for ALI due to high variability. We have observed that B6 mice from two SPF facilities at our University exhibit significantly different mortality and weight loss in response to BLM. To test whether the facility-dependent response to BLM can be transferred by the microbiome, we conventionalized germ-free (GF) B6 littermates in each facility and challenged with BLM. Conventionalized GF mice recapitulated the respective donors’ response to BLM. Further, fecal microbiota transfer from the facility where the mice had worse mortality into the mice in the facility with more survival rendered recipient mice more susceptible to BLM compared to controls, indicating that the differential gut microbiome between two facilities were sufficient to modulate BLM response. To identify microorganisms that drive the phenotype, we compared gut microbial community memberships by 16S rRNA and metagenomics sequencing. Interestingly, BLM highly susceptible mice had greater alpha diversity and harbored specific species of Bacteroides, Prevotella, and Helicobacter genera. Flow cytometry of the lung immune cell landscape at baseline revealed comparable composition and phenotype of adaptive immune cells regardless of facility. However, lung NK cells were significantly increased BLM highly susceptible mice. Thus, we demonstrate that distinct gut microbiota communities modulate death and weight loss in response to BLM-induced lung injury, implicating host-commensal interactions in regulating ALI outcomes.

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

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.

Sepsis plasma-derived exosomal miR-1-3p induces endothelial cell dysfunction by targeting SERP1.

Acute lung injury (ALI) is the leading cause of death in sepsis patients. Exosomes participate in the occurrence and development of ALI by regulating endothelial cell inflammatory response, oxidative stress and apoptosis, causing serious pulmonary vascular leakage and interstitial edema. The current study investigated the effect of exosomal miRNAs on endothelial cells during sepsis. We found a significant increase in miR-1-3p expression in cecal ligation and puncture (CLP) rats exosomes sequencing and sepsis patients’ exosomes, and lipopolysaccharide (LPS)-stimulated human umbilical vein endothelial cells (HUVECs) in vitro. However, the specific biological function of miR-1-3p in ALI remains unknown. Therefore, mimics or inhibitors of miR-1-3p were transfected to modulate its expression in HUVECs. Cell proliferation, apoptosis, contraction, permeability, and membrane injury were examined via cell counting kit-8 (CCK-8), flow cytometry, phalloidin staining, Transwell assay, lactate dehydrogenase (LDH) activity, and Western blotting. The miR-1-3p target gene was predicted with miRNA-related databases and validated by luciferase reporter. Target gene expression was blocked by siRNA to explore the underlying mechanisms. The results illustrated increased miR-1-3p and decreased stress-associated endoplasmic reticulum protein 1 (SERP1) expression both in vivo and in vitro. SERP1 was a direct target gene of miR-1-3p. Up-regulated miR-1-3p inhibits cell proliferation, promotes apoptosis and cytoskeleton contraction, increases monolayer endothelial cell permeability and membrane injury by targeting SERP1, which leads to dysfunction of endothelial cells and weakens vascular barrier function involved in the development of ALI. MiR-1-3p and SERP1 may be promising therapeutic candidates for sepsis-induced lung injury.

MicroRNA-499-5p targets SIRT1 to aggravate lipopolysaccharide-induced acute lung injury

Acute lung injury (ALI) is a life-threatening disease without effective and specific therapeutic strategies except the life-supporting treatments. Inflammation and oxidative stress are essential for the progression of ALI. MicroRNA-499-5p (miR-499-5p) has multiple pathophysiological actions; however, its function and mechanisms in ALI remain elusive. Mice were intravenously injected with miR-499-5p agomir, antagomir or the negative controls for 3 consecutive days and then received a single intratracheal injection of lipopolysaccharide (LPS, 5 mg/kg) to generate ALI model. Twenty four hours prior to LPS injection, EX-527 (1 mg/kg) was applied to inhibit SIRT1 activity. We identified a significant upregulation of miR-499-5p in LPS-treated lung tissues. miR-499-5p antagomir prevented, while miR-499-5p agomir promoted inflammation, oxidative stress and ALI in LPS-treated mice. Further studies indicated that miR-499-5p directly bound to the 3’-untranslated region of Sirtuin 1 (Sirt1) and decreased its protein level. SIRT1 inhibition blocked miR-499-5p antagomir-mediated pulmonary protection against LPS injury. miR-499-5p targets SIRT1 to aggravate LPS-induced ALI and it is a promising therapeutic target for the treatment of ALI.

The Mitochondrial Redistribution of eNOS is involved in Lipopolysaccharide Induced Inflammasome Activation During Acute Lung Injury

Acute lung injury (ALI) is a devastating clinical syndrome with no effective therapies. Inflammasome activation has been reported to play a critical role in the initiation and progression of ALI. The molecular mechanisms involved in regulating the activation of inflammasome in ALI remains unresolved, although increases in mitochondrial derived reactive oxygen species (mito-ROS) are involved. Our previous work has shown that the mitochondrial redistribution of uncoupled eNOS impairs mitochondrial bioenergetics and increases mito-ROS generation. Thus, the focus of our study was to determine if lipopolysaccharide (LPS)-mediated inflammasome activation involves the mitochondrial redistribution of uncoupled eNOS. Our data show that the increase in mito-ROS involved in LPS-mediated inflammasome activation is associated with the disruption of mitochondrial bioenergetics in human lung microvascular endothelial cells (HLMVEC) and the mitochondrial redistribution of eNOS. These effects are dependent on RhoA-ROCK signaling and are mediated via increased phosphorylation of eNOS at Threonine (T)-495. A derivative of the mitochondrial targeted Szeto-Schiller peptide (SSP) attached to the antioxidant Tiron (T-SSP), significantly attenuated LPS-mediated mito-ROS generation and inflammasome activation in HLMVEC. Further, T-SSP attenuated mitochondrial superoxide production in a mouse model of sepsis induced ALI. This in turn significantly reduced the inflammatory response and attenuated lung injury. Thus, our findings show that the mitochondrial redistribution of uncoupled eNOS is intimately involved in the activation of the inflammatory response in ALI and implicate attenuating mito-ROS as a therapeutic strategy in humans.

SIRT7 deficiency suppresses inflammation, induces EndoMT, and increases vascular permeability in primary pulmonary endothelial cells

Acute lung injury (ALI), a common condition in critically ill patients, has limited treatments and high mortality. Aging is a risk factor for ALI. Sirtuins (SIRTs), central regulators of the aging process, decrease during normal aging and in aging-related diseases. We recently showed decreased SIRT7 expression in lung tissues and fibroblasts from patients with pulmonary fibrosis compared to controls. To gain insight into aging-related mechanisms in ALI, we investigated the effects of SIRT7 depletion on lipopolysaccharide (LPS)-induced inflammatory responses and endothelial barrier permeability in human primary pulmonary endothelial cells. Silencing SIRT7 in pulmonary artery or microvascular endothelial cells attenuated LPS-induced increases in ICAM1, VCAM1, IL8, and IL6 and induced endomesenchymal transition (EndoMT) with decreases in VE-Cadherin and PECAM1 and increases in collagen, alpha-smooth muscle actin, TGFβ receptor 1, and the transcription factor Snail. Loss of endothelial adhesion molecules was accompanied by increased F-actin stress fibers and increased endothelial barrier permeability. Together, these results show that an aging phenotype induced by SIRT7 deficiency promotes EndoMT with impaired inflammatory responses and dysfunction of the lung vascular barrier.

Nesfatin-1 alleviates acute lung injury through reducing inflammation and oxidative stress via the regulation of HMGB1.

Acute lung injury (ALI) is the most common complication of sepsis, with rapid onset and high mortality. There is currently no effective treatment for ALI. Therefore, we looked for a good method of treating ALI by studying the effect and mechanism of Nesfatin-1 on ALI. We used LPS to induce mouse and human alveolar epithelial cell line BEAS-2B to construct an ALI model. Recombinant Nesfatin-1 was administered subcutaneously to mice or used to stimulate BEAS-2B cells. We collected mouse bronchoalveolar lavage fluid and mouse lung tissue to detect changes in inflammatory factors and oxidative stress levels. In addition, we examined the expression changes of HMGB1 to study the mechanism of Nesfatin-1. Exogenous Nesfatin-1 significantly attenuated LPS-induced ALI and reduced inflammation levels and oxidative stress levels in mouse lung tissue. In cell experiments, Nesfatin-1 also reduced inflammation levels and oxidative stress levels in BEAS-2B cells. In addition, Nesfatin-1 reduced the expression of HMGB1 in mouse lung tissues and BEAS-2B cells, and decreased the activity of p38MAPK and NF-κB signaling pathways in the inflammation-related pathway downstream of HMGB1. However, after overexpression of HMGB1, the therapeutic effect of Nesfatin-1 on ALI was attenuated. Nesfatin-1 regulates the expression of HMGB1 in alveolar epithelial cells. By reducing the expression of HMGB1, Nesfatin-1 can reduce the inflammation-related signaling pathway downstream of HMGB1 to reduce the level of inflammation and oxidative stress in alveolar epithelial cells, thereby alleviating ALI.