Mouse Model Of Lung Injury Research Articles

Sinapultide-Loaded Microbubbles Combined with Ultrasound to Attenuate Lipopolysaccharide-Induced Acute Lung Injury in Mice.

PurposePulmonary surfactants (eg, sinapultide) are widely used for the treatment of lung injury diseases; however, they generally induce poor therapeutic efficacy in clinics. In this study, sinapultide-loaded microbubbles (MBs) were prepared and combined with ultrasound (US) treatment as a new strategy for improved treatment of lung injury diseases.MethodsThe combination treatment strategy of MBs combined with ultrasound was tested in a lipopolysaccharide (LPS)-induced mouse model of alveolar epithelial cells (AT II) and acute lung injury. Firstly, cytotoxicity, cytokines, and protein levels in LPS-mediated AT II cells were assessed. Secondly, the pathological morphology of lung tissue, the wet/dry (W/D) weight ratio, cytokines, and protein levels in LPS-mediated acute lung injury mice after treatment with the MBs were evaluated. Moreover, histology examination of the heart, liver, spleen, lung and kidney of mice treated with the MBs was performed to initially evaluate the safety of the sinapultide-loaded MBs.ResultsSinapultide-loaded MBs in combination with ultrasound treatment significantly reduced the secretion of inflammatory cytokines and increased the expression of surfactant protein A (SP-A) in AT II cells. Furthermore, the pathological morphology of lung tissue, the wet/dry (W/D) weight ratio, interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α) and SP-A expression level of mice treated with MBs and ultrasound were significantly improved compared to those of non-treated mice. In addition, the histology of the examined organs showed that the MBs had a good safety profile.ConclusionSinapultide-loaded MBs combined with ultrasonic treatment may be a new therapeutic option for lung injury diseases in the clinic.

MiR-484: A Possible Indicator of Drug-Induced Pulmonary Fibrosis.

Drug-induced lung injury leads to serious lung diseases, such as pulmonary fibrosis. We demonstrated in an alveolar epithelial cell line A549/ABCA3 that certain microRNAs were associated with bleomycin induced epithelial-mesenchymal transition (EMT) which is closely related to pulmonary fibrosis. In this study, we focused on the role of miR-484 in drug-induced EMT using A549/ABCA3 cells and a mouse lung injury model. The expression of EMT-related genes and miR-484 was detected by real-time polymerase chain reaction. miR-484-targeted proteins were analyzed by Western blot. Pulmonary fibrosis mouse model was prepared by the intratracheal administration of BLM. As miR-484 is known to target SMAD2 and zinc finger E-box binding homeobox 1 (ZEB1), which are the well-known EMT-related transcription factors, we assessed the effects of a miR-484 inhibitor or mimic on the mRNA/protein expression of both the factors. We found that bleomycin significantly suppressed the intracellular expression and extracellular release of miR-484 in A549/ABCA3 cells. Moreover, the miR-484 mimic and inhibitor showed no drastic effects on the expression of the EMT-related transcription factors. In addition, the miR-484 mimic had no effect on the bleomycin-induced altered mRNA expression of the α-smooth muscle actin, a representative EMT marker. This suggested that miR-484 did not directly contribute to bleomycin-induced EMT in A549/ABCA3 cells. In contrast, the significant decrease in miR-484 expression in the lung tissue or plasma of bleomycin-administered mice suggested that miR-484 expression was closely correlated with bleomycin-induced lung injury. These findings indicate that miR-484 could be a novel diagnostic indicator for drug-induced pulmonary fibrosis.

Long non-coding RNA SNHG5 suppresses the development of acute respiratory distress syndrome by targeting miR-205/COMMD1 axis.

Previous studies have reported the important roles of long non-coding RNAs (lncRNAs) in acute respiratory distress syndrome (ARDS). Here, we focus on the role and regulatory mechanism of lncRNA SNHG5 in ARDS. LPS was used to induce mice to establish ARDS model in vivo and to induce A549 cells to establish ARDS model in vitro. qRT-PCR was performed to determine the expressions of SNHG5, miR-205, and inflammatory cytokines. MTT assay was applied to detect cell viability. Dual-luciferase reporter (DLR) assay was performed to test the interactions among SNHG5, miR-205 and COMMD1. Western blot was used to detect the protein expression of COMMD1. Lung injury was evaluated by evaluating the score of lung injury, lung wet/dry weight ratio, and myeloperoxidase (MPO) activity. SNHG5 was downregulated, while miR-205 was upregulated in the serum of ARDS patients and lung tissues of LPS-induced mice. Upregulation of SNHG5 or down-regulation of miR-205 inhibited inflammation and promoted the viability of LPS-induced A549 cells. SNHG5 alleviated the lung injury of ARDS mice. MiR-205 was a target of SNHG5 and inversely correlated with SNHG5. COMMD1 was targeted by miR-205, and was positively regulated by SNHG5. MiR-205 mimics or sh-COMMD1 reversed the promoting effect of SNHG5 on cell viability and the suppressing effect of SNHG5 on inflammation in cellular model of ARDS. Meantime, miR-205 mimics reversed the relieving effect of SNHG5 on lung injury in mouse model of ARDS. SNHG5 acted as a sponge for miR-205 to ameliorate LPS-induced ARDS by regulating COMMD1.

CTRP4 acts as an anti-inflammatory factor in macrophages and protects against endotoxic shock.

Despite the availability of antibiotics, current therapies to treat sepsis are still ineffective and many clinical trials aimed at neutralizing specific inflammatory cytokines have failed, suggesting the urgent need for new treatments. Using two models of LPS-induced endotoxemia and cecal ligation and puncture (CLP)-induced sepsis, we investigated the effects of C1q/TNF-related protein 4(CTRP4) on septic lethality and sepsis-induced inflammation. The effects of CTRP4 on survival, inflammation, organ damage, and bacterial clearance were assessed. Here, we found that CTRP4 decreased the mortalities of mice and alleviated pathological lung injury in mice model. In vivo depletion and adoptive transfer studies showed CTRP4-expressing macrophages as the key cell type inhibiting LPS-induced septic shock. The mechanism associated with the CTRP4 deficiency involved promoting of TLR4 internalization and activation of downstream pathways that resulted in a lethal, prolonged proinflammatory cytokine storm. Treatment of macrophages with exogenous CTRP4 abrogated proinflammatory cytokine production. Our results showed CTRP4 regulates inflammatory response and could be a promising strategy to treat septic shock.

Cytokine Panels and Pediatric Acute Respiratory Distress Syndrome: A Translational Investigation.

To identify and compare serum and lower respiratory tract fluid biomarkers of lung injury using well-characterized mouse models of lung injury. To explore the relationship between these preclinical biomarkers and clinical outcomes in a discovery cohort of pediatric patients with acute respiratory failure from pneumonia. Prospective, observational cohort study. A basic science laboratory and the PICU of a tertiary-care children's hospital. PICU patients intubated for respiratory failure from a suspected respiratory infection. Prospective enrollment and collection of lower respiratory tract fluid samples. C57BL6/J mice were intranasally inoculated with escalating doses of influenza A virus or toll-like receptor agonists to simulate varying degrees of lung injury. Serum and bronchoalveolar lavage fluid were measured for the presence of cytokines using commercially available multiplex cytokine assays. Elevated levels of C-C motif chemokine ligand 7 at the peak of inflammation in both bronchoalveolar lavage fluid and serum correlated with lethality, with the bronchoalveolar lavage fluid ratio of C-C motif chemokine ligand 7:C-C motif chemokine ligand 22 providing the best prediction in the mouse models. These preclinical biomarkers were examined in the plasma and lower respiratory tract fluid of a discovery cohort of pediatric patients with acute respiratory failure from pneumonia. The primary clinical outcome measure was ventilator-free days, with secondary outcomes of pediatric acute respiratory distress syndrome severity and mortality. Elevation in peak lower respiratory tract fluid C-C motif chemokine ligand 7:C-C motif chemokine ligand 22 ratios demonstrated a significant negative correlation with ventilator-free days (r = -0.805; p < 0.02). This study provides evidence that lung immune profiling via lower respiratory tract fluid cytokine analysis is feasible and may provide insight into clinical outcomes. Further validation of markers, including the C-C motif chemokine ligand 7:C-C motif chemokine ligand 22 ratio in this limited study, in a larger cohort of patients is necessary.

Clinical Trial to Evaluate an Approved ITP Therapy Targeting Spleen Tyrosine Kinase (SYK) for Prevention and Treatment of COVID-19 Related Complications

Fostamatinib is a potent SYK inhibitor that targets activation of both the innate and acquired immune systems caused by tissue damage or pathogen signals via C-type lectin receptors (CLR) as well as by antibody-antigen immune complexes via Fc receptors (Figure 1). SYK is also a key modulator of pathways involved in thrombosis formation. Fostamatinib is FDA-approved for chronic immune thrombocytopenia (ITP) and has been evaluated in over 4000 patients for treatment of allergic, autoimmune, and neoplastic disorders. Fostamatinib is well tolerated, with a consistent safety profile across a number of diseases. In rheumatoid arthritis patients, fostamatinib reduced the plasma levels of IL-6.1 The active metabolite (R406) was protective in mouse models of LPS-induced acute lung injury (ALI)2 and LPS- or antibody-induced acute kidney injury (AKI).3 SYK inhibition decreased the incidence of thrombosis in mouse models of thromboembolism,4 and the incidence of thromboembolic events was decreased in patients treated with fostamatinib compared with other treatments for ITP. These immunomodulatory effects suggest that SYK inhibition represents a new therapeutic strategy for the treatment of COVID-19, which led to design of a clinical study of fostamatinib in hospitalized COVID-19 patients.COVID-19 patients are at risk for a potentially fatal acute respiratory distress syndrome (ARDS), cytokine storm, severe systemic capillary leak syndrome, thromboembolic events, and multi-organ dysfunction/failure. SYK is a master regulator of signal transduction pathways implicated in these COVID-19 associated complications, which involves hyperactivation of both innate and acquired immune systems. Targeting SYK could prevent the cytokine storm, downstream activation of endothelial cells and platelets, and influx of neutrophils and monocytes into lungs or kidney leading to ALI and AKI, respectively.Methods: A randomized, double-blind, placebo-controlled, multi-center, Phase 3 study will evaluate the efficacy and safety of fostamatinib in adult, hospitalized, high-risk COVID-19 patients. Patients will be treated with fostamatinib 150mg BID for up to 28 days plus standard of care. Improvement in clinical status will be assessed using the 8-point ordinal scale.

Human Placental Hematopoietic Stem Cell Derived Natural Killer Cells (CYNK-001) Mediate Protection Against Influenza A Viral Infection

Background: Influenza A virus (IAV) infections are associated with a high healthcare burden around the world and there is an urgent need to develop more effective therapies. Natural killer (NK) cells provide the first line of innate defense against IAV by killing infected epithelial cells, by producing antiviral cytokines and affecting adaptive immunity. Preclinical studies have demonstrated that NK cells play a pivotal role in reducing IAV-induced pulmonary infection; however, little is known about the therapeutic potential of adoptively transferred NK cells for IAV infections. Celularity Inc. is developing human placental hematopoietic stem cell-derived allogeneic, off-the-shelf NK cell therapy (CYNK-001) for the treatment of viral infections, including coronavirus disease of 2019. Here, we report the evaluation of antiviral activities of CYNK-001 against IAV infection.Methods:In vitro antiviral activities of CYNK-001 were evaluated using human alveolar epithelial cell line A549, infected with IAV strain A/PR/8/34 (H1N1) at variable multiplicity of infection (MOI). The expression of ligands for NK cell receptors was analyzed on infected A549 cells using Fc-coupled recombinant proteins. CYNK-001 was added to A549 cells 16 hours post infection. CYNK-001 degranulation was measured after 4 hours of coculture, and CYNK-001 cytotoxicity against IAV-infected A549 was measured real-time using impedance-based xCELLigence platform. In vivo antiviral and immunomodulatory activities of CYNK-001 were assessed in A/PR/8/34 (H1N1)-induced severe acute lung injury mouse model. Mice were intranasally infected with 2500 PFU IAV. PBS or 1 x 107 CYNK-001 cells were intravenously administered twice at 1 and 3 days post infection (dpi). At 6 dpi, lungs were collected for the evaluation of viral load by qPCR, lung injury and immune cell profiling by histology. Bronchoalveolar lavage fluid (BALF) was collected at 6 dpi for cytokine analysis by multiplex assays, total protein concentration by ELISA and immune cell profiling by flow cytometry.Results:In vitro, IAV infection corresponded with dose-dependent expression of ligands to NK cell-activating receptors, including NKp44, NKp46 and NKG2D. CYNK-001 cells exhibited increased IFNγ, TNFα and GM-CSF production, and elevated level of degranulation upon coculture with IAV-infected A549 cells. Cytokines in culture supernatant and CD107a expression in CYNK-001 cells were upregulated in a virus dose-dependent manner. Consistent with this finding, CYNK-001 cytotoxicity against IAV-infected A549 cells increased from 35% at 0 MOI to 50%, 60% and 75% at 0.001, 0.01 and 0.1 MOI, respectively. These data indicate that CYNK-001 cells recognize virally infected cells, resulting in specific cytotoxic elimination of the source of infection. In vivo, treatment of IAV-infected mice with CYNK-001 reduced weight loss and increased their likelihood of survival. PBS control group developed a severe disease and 37.5% mortality was observed as early as day 4. In the group treated with CYNK-001, disease onset was delayed by 2 days. qPCR analysis of viral RNA showed that CYNK-001-treated mice had lower viral load in the lung than vehicle-treated mice, demonstrating antiviral function of CYNK-001 in vivo. CYNK-001-treated mice had reduced lung injury as assessed by lower total protein concentration in BALF. Moreover, CYNK-001 reduced BALF murine cytokines and chemokines, including IFNγ (p<0.001), IL-6, TNFα, MCP-1 (p<0.05), CXCL2 and CXCL9. Lastly, immunohistochemical analysis of the lung showed that CYNK-001-treated mice had an altered immune response to IAV with higher number of CD68+ macrophages and CD8+ T cells at 6 dpi.Conclusions: Our in vitro and in vivo data show the promising antiviral activities of CYNK-001 against IAV infection. In a severe IAV infection mouse model, CYNK-001 treatment demonstrates lower mortality rate, lower weight loss, lower lung viral load and reduced lung injury along with reduced inflammation. These results support our hypothesis that the adoptive transfer of CYNK-001 could reduce the burden of viral infection through the elimination of infected epithelial cells, coordinate a more effective immune response, and result in a clinical benefit in patients with severe viral infection.DisclosuresHe:Celularity Inc.: Current Employment. Mahlakõiv:Celularity Inc.: Current Employment. Gleason:Celularity Inc.: Current Employment, Current equity holder in private company. Van Der Touw:Celularity Inc.: Current Employment. Kang:Celularity Inc.: Current Employment. Hariri:Celularity Inc.: Current Employment, Current equity holder in private company. Zhang:Celularity Inc.: Current Employment, Current equity holder in private company.

NK cell-derived exosomes improved lung injury in mouse model of Pseudomonas aeruginosa lung infection

BackgroundPseudomonas aeruginosa (PA) is one of the most common bacteria that causes lung infection in hospital. The aim of our study is to explore the role and action mechanism of NK cells in lung PA infection.MethodsIn this present study, 2.5 × 108 CFU/mouse PA was injected into murine trachea to make lung PA infection mouse model. Anti-asialo GM1 was used to inhibit NK cell. The percentage of NK cells was ensured by flow cytometry, and the M1- and M2-polarized macrophages were determined by flow cytometry, qRT-PCR, and ELISA assay. Besides, H&E staining was performed to ensure the pathological changes in lung tissues. Transmission electron microscopy and western blot were carried out to identify the exosome.ResultsHere, in the mouse model of PA lung infection, NK cell depletion caused M2 polarization of lung macrophage, and exacerbated PA-induced lung injury. Next, our data shown that M2 macrophage polarization was enhanced when the generation of NK cell-derived exosome was blocked in the co-culture system of NK cells and macrophages. Subsequently, we demonstrated that NK cells promoted M1 macrophage polarization both in PA-infected macrophage and the mouse model of PA lung infection, and attenuated lung injury through exosome.ConclusionOverall, our data proved that NK cell may improve PA-induced lung injury through promoting M1 lung macrophage polarization by secreting exosome. Our results provide a new idea for the treatment of PA lung infection.

Growth Hormone-Releasing Hormone in Lung Physiology and Pulmonary Disease.

Growth hormone-releasing hormone (GHRH) is secreted primarily from the hypothalamus, but other tissues, including the lungs, produce it locally. GHRH stimulates the release and secretion of growth hormone (GH) by the pituitary and regulates the production of GH and hepatic insulin-like growth factor-1 (IGF-1). Pituitary-type GHRH-receptors (GHRH-R) are expressed in human lungs, indicating that GHRH or GH could participate in lung development, growth, and repair. GHRH-R antagonists (i.e., synthetic peptides), which we have tested in various models, exert growth-inhibitory effects in lung cancer cells in vitro and in vivo in addition to having anti-inflammatory, anti-oxidative, and pro-apoptotic effects. One antagonist of the GHRH-R used in recent studies reviewed here, MIA-602, lessens both inflammation and fibrosis in a mouse model of bleomycin lung injury. GHRH and its peptide agonists regulate the proliferation of fibroblasts through the modulation of extracellular signal-regulated kinase (ERK) and Akt pathways. In addition to downregulating GH and IGF-1, GHRH-R antagonist MIA-602 inhibits signaling pathways relevant to inflammation, including p21-activated kinase 1-signal transducer and activator of transcription 3/nuclear factor-kappa B (PAK1-STAT3/NF-κB and ERK). MIA-602 induces fibroblast apoptosis in a dose-dependent manner, which is an effect that is likely important in antifibrotic actions. Taken together, the novel data reviewed here show that GHRH is an important peptide that participates in lung homeostasis, inflammation, wound healing, and cancer; and GHRH-R antagonists may have therapeutic potential in lung diseases.

Micelles self-assembled by 3-O-\u03b2-d-glucopyranosyl latycodigenin enhance cell membrane permeability, promote antibiotic pulmonary targeting and improve anti-infective efficacy

BackgroundNanoparticle-based pulmonary drug delivery systems are commonly developed and applied for drug-targeted delivery. They exhibit significant advantages compared to traditional pulmonary drug delivery systems. However, developing the formulation of each drug is a time-consuming and laborious task.ResultsIn this study, a universal lung-targeting nanoparticle was designed and constructed. The self-assembled micelles were composed of a platycodon secondary saponin, 3-O-β-d-glucopyranosyl platycodigenin 682 (GP-682), based on its specific amphiphilic structure. The GP-682 micelles exhibited a relatively stable zeta potential with a particle size between 60 and 90 nm, and the critical micelle concentration (CMC) value was approximately 42.3 μg/mL. Preincubation of GP-682 micelles markedly enhanced their cell membrane permeability and improved drug uptake in vitro. The results were visualized using fluorescent dye tracing, transmission electron microscopy (TEM) observations and the lactate dehydrogenase (LDH) release assay. The obtained benefits enhanced the distribution of levofloxacin (Lev) in mouse lung tissue and reduced antibiotics overdosing. The acute lung injury mouse model induced by the Pseudomonas aeruginosa PA 14 strain demonstrated that preinjection of GP-682 micelles before antibiotic administration resulted in a higher survival rate and anti-infective efficacy in vivo. It also caused reductions in pulmonary injury, bacterial invasion and cytokine expression compared with treatment with Lev alone.ConclusionsGP-682 micelles are another nanoparticle-based pulmonary drug delivery system and provide a new lung-targeting therapy option.

Aging Influences the Metabolic and Inflammatory Phenotype in an Experimental Mouse Model of Acute Lung Injury.

Increased age is a risk factor for poor outcomes from respiratory failure and acute respiratory distress syndrome (ARDS). In this study, we sought to define age-related differences in lung inflammation, muscle injury, and metabolism after intratracheal lipopolysaccharide (IT-LPS) acute lung injury (ALI) in adult (6 months) and aged (18-20 months) male C57BL/6 mice. We also investigated age-related changes in muscle fatty acid oxidation (FAO) and the consequences of systemic FAO inhibition with the drug etomoxir. Aged mice had a distinct lung injury course characterized by prolonged alveolar neutrophilia and lack of response to therapeutic exercise. To assess the metabolic consequences of ALI, aged and adult mice underwent whole body metabolic phenotyping before and after IT-LPS. Aged mice had prolonged anorexia and decreased respiratory exchange ratio, indicating increased reliance on FAO. Etomoxir increased mortality in aged but not adult ALI mice, confirming the importance of FAO on survival from acute severe stress and suggesting that adult mice have increased resilience to FAO inhibition. Skeletal muscles from aged ALI mice had increased transcription of key fatty acid metabolizing enzymes, CPT-1b, LCAD, MCAD, FATP1 and UCP3. Additionally, aged mice had increased protein levels of CPT-1b at baseline and after lung injury. Surprisingly, CPT-1b in isolated skeletal muscle mitochondria had decreased activity in aged mice compared to adults. The distinct phenotype of aged ALI mice has similar characteristics to the adverse age-related outcomes of ARDS. This model may be useful to examine and augment immunologic and metabolic abnormalities unique to the critically ill aged population.

Heme oxygenase-1 (HO-1) cytoprotective pathway: A potential treatment strategy against coronavirus disease 2019 (COVID-19)-induced cytokine storm syndrome

The outbreak of coronavirus disease 2019 (COVID-19) requires urgent need for effective treatment. Severe COVID-19 is characterized by a cytokine storm syndrome with subsequent multiple organ failure (MOF) and acute respiratory distress syndrome (ARDS), which may lead to intensive care unit and increased risk of death.While awaiting a vaccine, targeting COVID-19-induced cytokine storm syndrome appears currently as the efficient strategy to reduce the mortality of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).The stress-responsive enzyme, heme oxygenase-1 (HO-1) is largely known to protect against inflammatory response in animal models. HO-1 is induced by hemin, a well-tolerated molecule, used for decades in the treatment of acute intermittent porphyria. Experimental studies showed that hemin-induced HO-1 mitigates cytokine storm and lung injury in mouse models of sepsis and renal ischemia-reperfusion injury. Furthermore, HO-1 may also control numerous viral infections by inhibiting virus replication.In this context, we suggest the hypothesis that HO-1 cytoprotective pathway might be a promising target to control SARS-CoV-2 infection and mitigate COVID-19-induced cytokine storm and subsequent ARDS.

Lycorine attenuates lipopolysaccharide-induced acute lung injury through the HMGB1/TLRs/NF-κB pathway.

Lung injury associated with systemic inflammatory response is a common problem affecting human health. Previous studies have shown that lycorine exerts a anti-inflammatory effect. However, whether lycorine alleviates lung injury remains unclear. To explore this issue, BALB/c mice and MLE-12 cells were treated with lipopolysaccharide (LPS) to establish lung injury mouse model and cell model, respectively. Glycyrrhizic acid, known as an inhibitor of ALI, was also used to study the effects of lycorine in vitro. Our results showed that after LPS treatment, the lung injury score, lung wet-to-dry weight ratio, and malondialdehyde (MDA) production in the lung tissues and the expression levels of tumor necrosis factor-α, interleukin-1β, and interleukin-6 in bronchoalveolar lavage fluid were significantly increased, whereas their levels were decreased by lycorine. Additionally, LPS injection activated the high-mobility group box 1 (HMGB1)/Toll-like receptors (TLRs)/NF-κB pathway. However, lycorine treatment attenuated the activity of the HMGB1/TLRs/NF-κB pathway in the lung tissues. In vitro studies showed that lycorine administration significantly decreased the levels of inflammatory cytokines and MDA and attenuated the activity of the HMGB1/TLRs/NF-κB pathway in LPS-treated cells. Moreover, the inhibitory effects of lycorine on the inflammatory response and oxidative stress in LPS-treated lung cells were similar with that of glycyrrhizic acid, and this inhibition was intensified by both lycorine and glycyrrhizic acid treatment. We suggest that lycorine could alleviate LPS-induced lung injury of inflammation and oxidative stress by blocking the HMGB1/TLRs/NF-κB pathway, which gives a new perspective for ALI therapy to treat lycorine as a potential treatment clinically.

Glucagon-like peptide-1 receptor mediates the beneficial effect of liraglutide in an acute lung injury mouse model involving the thioredoxin-interacting protein.

Repurposing clinically used drugs is among the important strategies in drug discovery. Glucagon-like peptide-1 (GLP-1) and its diabetes-based drugs, such as liraglutide, possess a spectrum of extra-pancreatic functions, while GLP-1 receptor (GLP-1R) is most abundantly expressed in the lung. Recent studies have suggested that GLP-1-based drugs exert beneficial effects in chronic, as well as acute, lung injury rodent models. Here, we show that liraglutide pretreatment reduced LPS induced acute lung injury in mice. It significantly reduced lung injury score, wet/dry lung weight ratio, bronchoalveolar lavage fluid immune cell count and protein concentration, and cell apoptosis in the lung, and it was associated with reduced lung inflammatory cytokine and chemokine gene expression. Importantly, these effects were virtually absent in GLP-1R−/− mice. A well-known function of GLP-1 and GLP-based drugs in pancreatic β-cells is the attenuation of high-glucose stimulated expression of thioredoxin-interacting protein (TxNIP), a key component of inflammasome. LPS-challenged lungs showed elevated TxNIP mRNA and protein expression, which was attenuated by liraglutide treatment in a GLP-1R-dependent manner. Hence, our observations suggest that GLP-1R is essential in mediating beneficial effects of liraglutide in acute lung injury, with the inflammasome component TxNIP as a potential target.

The MUC5B Mucin Is Involved in Paraquat-Induced Lung Inflammation.

Objective Paraquat (PQ), a widely used toxic herbicide, induces lung inflammation through mechanisms that remain incompletely understood. In a previous study, we found that the plasma MUC5B mucin level was implicated in PQ poisoning in patients. Here, we hypothesize that MUC5B is a critical mediator in PQ-induced cell inflammation. Methods A mouse model of PQ-induced lung injury was used to examine the MUC5B expression level. A549 cells (alveolar epithelial cells line) were exposed to PQ in dose-dependent and time-dependent manners. Cell viability was detected by CCK-8 assays. The expression levels of MUC5B were examined by dot blot enzyme-linked immunosorbent assay (ELISA) and RT-qPCR. Western blotting was used to detect the levels of proteins in the MAPK and NF-κB pathways. Inflammatory factors in the cell culture medium were measured by ELISA. NF-κB and MAPK pathway inhibitors and MUC5B siRNA (siMUC5B) were used to determine the function of MUC5B. Finally, N-acetyl-cysteine (NAC) was added and its regulatory effect on the MAPK-NF-κB-MUC5B pathway was examined in PQ-induced cell inflammation. Results MUC5B was significantly upregulated accompanying the increases in TNF-α and IL-6 secretion following PQ treatment in mouse and also in A549 cells after treatment with 50 μM PQ at 24 hours. Furthermore, MAPK and NF-κB pathway inhibitors could dramatically decrease the expression of MUC5B and the secretion of TNF-α and IL-6. Importantly, siMUC5B could significantly attenuate the secretion of TNF-α and IL-6 induced by PQ. As expected, the addition of NAC efficiently suppresses the TNF-α and IL-6 secretion stimulated from PQ and also downregulated ERK, JNK, and p65 phosphorylation (ERK/JNK MAPK and NF-κB pathways) as well as MUC5B expression. Conclusion Our findings suggest that MUC5B participates in the process of PQ-induced cell inflammation and is downstream of the NF-κB and MAPK pathways. NAC can attenuate PQ-induced cell inflammation at least in part by suppressing the MAPK-NF-κB-MUC5B pathway. These results nominate MUC5B as a new biomarker and therapeutic target for PQ-induced lung inflammation.

Immunity-and-matrix-regulatory cells derived from human embryonic stem cells safely and effectively treat mouse lung injury and fibrosis

Lung injury and fibrosis represent the most significant outcomes of severe and acute lung disorders, including COVID-19. However, there are still no effective drugs to treat lung injury and fibrosis. In this study, we report the generation of clinical-grade human embryonic stem cells (hESCs)-derived immunity- and matrix-regulatory cells (IMRCs) produced under good manufacturing practice requirements, that can treat lung injury and fibrosis in vivo. We generate IMRCs by sequentially differentiating hESCs with serum-free reagents. IMRCs possess a unique gene expression profile distinct from that of umbilical cord mesenchymal stem cells (UCMSCs), such as higher expression levels of proliferative, immunomodulatory and anti-fibrotic genes. Moreover, intravenous delivery of IMRCs inhibits both pulmonary inflammation and fibrosis in mouse models of lung injury, and significantly improves the survival rate of the recipient mice in a dose-dependent manner, likely through paracrine regulatory mechanisms. IMRCs are superior to both primary UCMSCs and the FDA-approved drug pirfenidone, with an excellent efficacy and safety profile in mice and monkeys. In light of public health crises involving pneumonia, acute lung injury and acute respiratory distress syndrome, our findings suggest that IMRCs are ready for clinical trials on lung disorders.

Impaired Breakdown of Bradykinin and Its Metabolites as a Possible Cause for Pulmonary Edema in COVID-19 Infection.

A growing body of clinical evidence shows that vascular leakage leads to pulmonary edema in coronavirus disease 2019 (COVID-19) patients. Coronaviruses including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) use membrane ectopeptidases to invade cells, most notably dipeptidyl peptidase 4 (DPP4; https://www.uniprot.org/uniprot/P27487), aminopeptidase N (APN; https://www.uniprot.org/uniprot/P15144), and angiotensin-converting enzyme 2 (ACE2; https://www.uniprot.org/uniprot/Q9BYF1).[1] It is important to distinguish this latter protein from ACE, which is the main target for conventional blood pressure lowering drugs: ACE inhibitors do not inhibit ACE2.[2] As a result of virus entry, these membrane ectopeptidases are internalized and their activity becomes downregulated. The common denominator between these membrane ectopeptidases is their enzyme specificity: they degrade peptide hormones, for instance, angiotensin II. For SARS-CoV-2 (as well as SARS-CoV), ACE2 is the predominant target for cellular uptake in vivo.[3] It is present on lung alveolar epithelial cells, enterocytes of the small intestine, endothelial cells, and arterial smooth muscle cells.[4] In an acid aspiration lung injury mouse model, ACE2 knockout (KO) worsened the resulting edema.[5] This was accompanied by increased angiotensin II levels[6] and was prevented by angiotensin II receptor KO, leading to the conclusion that the lack of ACE2-mediated angiotensin II degradation was responsible for the observed increase pulmonary vascular permeability. The same observations were made when downregulating ACE2 with the spike protein of the SARS CoV prior to acid aspiration.[6] Yet, the authors did not measure renin in these studies. This is crucial since normally angiotensin II rises result in rapid renin suppression,[7] thereby normalizing its levels. Moreover, ACE2 is just one of many angiotensin-degrading enzymes (angiotensinases). In full accordance with this concept, Gurley et al did not find increased angiotensin II levels after ACE2 KO.[8] Hence, whether the ACE2 KO dependent permeability changes are entirely due to ACE2-mediated angiotensin II degradation remains uncertain. ACE2 has multiple other substrates. Among these are the kinins, which are also degraded by DPP4.[9] We and others believe that this deserves attention, as it offers an alternative view, and forms a basis on which novel therapeutic opportunities might be proposed.[10]

Stabilization of the histone acetyltransferase Tip60 by deubiquitinating enzyme USP7 stimulates the release of pro-inflammatory mediators in acute lung injury.

Acute lung injury (ALI) is often associated with inflammation. Increasing evidence has identified the role for ubiquitin-specific protease 7 (USP7) in activating the expression of inflammatory factors in macrophages. The present study evaluated whether USP7 also mediates histone acetyltransferase Tat-interactive protein 60 (Tip60) in the development of ALI inflammation. An ALI mouse model was induced by intratracheal lipopolysaccharide (LPS) administration. Next, lung myeloperoxidase (MPO) activity and the ratio of dry weight/wet weight of lung were examined to evaluate tissue damage. In addition, RAW 264.7 cells were treated with LPS to induce an in vitro LPS-induced inflammatory cell model. ELISA was performed to measure expression of IL-1β, TNF-α, IL-6, and IL-8 in cells and tissues. TUNEL was used to detect LPS-induced cell apoptosis. Furthermore, the interaction between USP7 and Tip60 was identified by IP, Western blot analysis, and cycloheximide (CHX) treatment. The enrichment of Tip60 and H3K27ac in the promoter region of IL-6 and IL-8 was assessed by ChIP. USP7 was highly expressed in LPS-endotoxin-induced ALI mouse models and silencing of USP7 delayed the progression of ALI in mice. Silencing of USP7 protected RAW 264.7 cells against LPS-induced inflammation and apoptosis by downregulating IL-1β, TNF-α, IL-6, and IL-8. USP7 enhanced Tip60 protein stability, and Tip60 increased the enrichment of H3K27ac on IL-6 and IL-8 promoter region and activated NF-κB p65 to increase IL-6 and IL-8 expression. These findings reveal a new post-transcriptional role for USP7 in inflammation by stabilizing Tip60 and increasing the release of the pro-inflammatory cytokines, and implicate USP7 inhibitors as potential therapeutic agents for ALI. KEY MESSAGES: USP7 expresses highly in an acute lung injury (ALI) mouse models. Silencing of USP7 inhibits inflammation and cell apoptosis in ALI mouse. USP7 stabilizes Tip60 to boost the release of IL-6 and IL-8. Tip60 increases IL-6 and IL-8 expression by acetylating NF-κB p65. Silencing of USP7 alleviates ALI by repressing NF-κB p65 and Tip60.

Recommendations of RAAS Blocker Use Amidst The Coronavirus Pandemic

With a rapidly growing pandemic of coronavirus disease of 2019 (COVID-19), a public health emergency of international concern, the medical communities and national health systems are being tested for their preparedness. The culprit that is responsible for this viral respiratory disease, is a novel type of coronavirus, now identified as severe acute respiratory syndrome coronavirus - 2 (SARS-CoV2). At the present time, there are gaps in the knowledge regarding the safety of angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs) for COVID-19 patients due to concern of ACE2, which is critical for viral entry and their levels are upregulated when using these (Renin Angiotensin Aldosterone System) RAAS blockers. ACE2 is a glycoprotein metalloprotease that plays an essential role in physiologic and pathological states and it is ubiquitously found in human organs. Despite sharing homology, ACE is different from ACE2, and while the former cleaves angiotensin 1 to angiotensin 2, the latter cleaves angiotensin two to angiotensin 1-7. Extrapolated from experimental animal studies, ACE2 and angiotensin 1-7 are important and protective for the lung physiology based on mice model of acute lung injury by various causes. Other evidence also demonstrates harm over benefits when stopping RAAS blockers, particularly in patients with cardiovascular disease, in which using these drugs are proven to be life-saving. In the light of the paucity of evidence derived from well-designed study, societies and colleges recommend continuing RAAS blockers until new evidence says otherwise.

Recommendations of RAAS Blocker Use Amidst The Coronavirus Pandemic

With a rapidly growing pandemic of coronavirus disease of 2019 (COVID-19), a public health emergency of international concern, the medical communities and national health systems are being tested for their preparedness. The culprit that is responsible for this viral respiratory disease, is a novel type of coronavirus, now identified as severe acute respiratory syndrome coronavirus - 2 (SARS-CoV2). At the present time, there are gaps in the knowledge regarding the safety of angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs) for COVID-19 patients due to concern of ACE2, which is critical for viral entry and their levels are upregulated when using these (Renin Angiotensin Aldosterone System) RAAS blockers. ACE2 is a glycoprotein metalloprotease that plays an essential role in physiologic and pathological states and it is ubiquitously found in human organs. Despite sharing homology, ACE is different from ACE2, and while the former cleaves angiotensin 1 to angiotensin 2, the latter cleaves angiotensin two to angiotensin 1-7. Extrapolated from experimental animal studies, ACE2 and angiotensin 1-7 are important and protective for the lung physiology based on mice model of acute lung injury by various causes. Other evidence also demonstrates harm over benefits when stopping RAAS blockers, particularly in patients with cardiovascular disease, in which using these drugs are proven to be life-saving. In the light of the paucity of evidence derived from well-designed study, societies and colleges recommend continuing RAAS blockers until new evidence says otherwise.