Murine Alveolar Macrophage Cell Research Articles

Myeloid-specific Hdac10 deletion protects against LPS-induced acute lung injury via P62 acetylation at lysine 165

BackgroundAberrant activation of macrophages is associated with pathogenesis of acute lung injury (ALI). However, the potential pathogenesis has not been explored.ObjectivesWe aimed to identify whether histone deacetylase (HDAC) 10 is involved in lipopolysaccharide (LPS)-exposed ALI and reveal the underlying pathogenesis by which it promotes lung inflammation in LPS-exposed ALI via modifying P62 with deacetylation.MethodsWe constructed an ALI mice model stimulated with LPS to determine the positive effect of Hdac10 deficiency. Moreover, we cultured murine alveolar macrophage cell line (MH-S cells) and primary bone marrow-derived macrophages (BMDMs) to explore the pro-inflammatory activity and mechanism of HDAC10 after LPS challenge.ResultsHDAC10 expression was increased both in mice lung tissues and macrophage cell lines and promoted inflammatory cytokines production exposed to LPS. Hdac10 deficiency inhibited autophagy and inflammatory response after LPS stimulation. In vivo, Hdac10fl/fl-LysMCre mice considerably attenuated lung inflammation and inflammatory cytokines release exposed to LPS. Mechanistically, HDAC10 interacts with P62 and mediates P62 deacetylation at lysine 165 (K165), by which it promotes P62 expression and increases inflammatory cytokines production. Importantly, we identified that Salvianolic acid B (SAB), an HDAC10 inhibitor, reduces lung inflammatory response in LPS-stimulated ALI.ConclusionThese results uncover a previously unknown role for HDAC10 in regulating P62 deacetylation and aggravating lung inflammation in LPS-induced ALI, implicating that targeting HDAC10 is an effective therapy for LPS-exposed ALI.

Pioglitazone reverses alcohol-induced alterations in alveolar macrophage mitochondrial phenotype.

People with alcohol use disorder (AUD) have an increased risk of developing pneumonia and pulmonary diseases. Alveolar macrophages (AMs) are immune cells of the lower respiratory tract that are necessary for clearance of pathogens. However, alcohol causes AM oxidative stress, mitochondrial damage and dysfunction, and diminished phagocytic capacity, leading to lung injury and immune suppression. AMs were isolated by bronchoalveolar lavage from people with AUD and male and female C57BL/6J mice given chronic ethanol (20% w/v, 12 weeks) in drinking water. The peroxisome proliferator-activated receptor γ ligand, pioglitazone, was used to treat human AMs exvivo (10 μM, 24 h) and mice invivo by oral gavage (10 mg/kg/day). Levels of AM mitochondrial superoxide and hypoxia-inducible factor-1 alpha (HIF-1α) mRNA, a marker of oxidative stress, were measured by fluorescence microscopy and RT-qPCR, respectively. Mouse AM phagocytic ability was determined by internalized Staphylococcus aureus, and mitochondrial capacity, dependency, and flexibility for glucose, long-chain fatty acid, and glutamine oxidation were measured using an extracellular flux analyzer. Invitro studies used a murine AM cell line, MH-S (±0.08% ethanol, 72 h) to investigate mitochondrial fuel oxidation and ATP-linked respiration. Pioglitazone treatment decreased mitochondrial superoxide in AMs from people with AUD and ethanol-fed mice and HIF-1α mRNA in ethanol-fed mouse lungs. Pioglitazone also reversed mouse AM glutamine oxidation and glucose or long-chain fatty acid flexibility to meet basal oxidation needs. Invitro, ethanol decreased the rate of AM mitochondrial and total ATP production, and pioglitazone improved changes in glucose and glutamine oxidation. Pioglitazone reversed chronic alcohol-induced oxidative stress in human AM and mitochondrial substrate oxidation flexibility and superoxide levels in mouse AM. Decreased ethanol-induced AM HIF-1α mRNA with pioglitazone suggests that this pathway may be a focus for metabolic-targeted therapeutics to improve morbidity and mortality in people with AUD.

Exploring the Molecular Mechanism by which Kaempferol Attenuates Sepsis-related Acute Respiratory Distress Syndrome Based on Network Pharmacology and Experimental Verification.

Sepsis-related acute respiratory distress syndrome (ARDS) is a fatal disease without effective therapy. Kaempferol is a flavonoid compound extracted from natural plant products; it exerts numerous pharmacological effects. Kaempferol attenuates sepsis-related ARDS; however, the underlying protective mechanism has not been elucidated completely. This study aimed to use network pharmacology and experimental verification to investigate the mechanisms by which kaempferol attenuates sepsis-related ARDS. We screened the targets of kaempferol by PharMapper, Swiss Target Prediction, and CTD database. We identified the targets of sepsis-related ARDS by GeneCards, DisGeNet, OMIM, and TTD. The Weishengxin platform was used to map the targets of both kaempferol and sepsis-related ARDS. We created a Venn diagram to identify the intersection targets. We constructed the "component-intersection targets-disease" network diagram using Cytoscape 3.9.1 software. The intersection targets were imported into the STRING database for developing the protein-protein interaction network. Metascape was used for the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis. We selected the leading 20 KEGG pathways to establish the KEGG relationship network. Finally, we performed experimental verification to confirm our prediction results. Through database screening, we obtained 502, 360, and 78 kaempferol targets, disease targets of sepsis-related ARDS, and intersection targets, respectively. The core targets consisted of tumor necrosis factor-alpha (TNF-α), interleukin (IL)-6, albumin (ALB), IL-1β, and AKT serine/ threonine kinase (AKT)1. GO enrichment analysis identified 426 items, which were principally involved in response to lipopolysaccharide, regulation of inflammatory response, inflammatory response, positive regulation of cell migration, positive regulation of cell adhesion, positive regulation of protein phosphorylation, response to hormone, regulation of reactive oxygen species (ROS) metabolic process, negative regulation of apoptotic signaling pathway, and response to decreased oxygen levels. KEGG enrichment analysis identified 151 pathways. After eliminating the disease and generalized pathways, we obtained the hypoxia-inducible factor 1 (HIF-1), nuclear factor κB (NF-κB), and phosphoinositide 3-kinase (PI3K)-Akt signaling pathways. Our experimental verification confirmed that kaempferol blocked the HIF-1, NF-κB, and PI3K-Akt signaling pathways, diminished TNF-α, IL-1β, and IL-6 expressions, suppressed ROS production, and inhibited apoptosis in lipopolysaccharide (LPS)-induced murine alveolar macrophage (MH-S) cells. Kaempferol can reduce inflammatory response, ROS production, and cell apoptosis by acting on the HIF-1, NF-κB, and PI3K-Akt signaling pathways, thereby alleviating sepsis- related ARDS.

Protective mechanism of quercetin in alleviating sepsis-related acute respiratory distress syndrome based on network pharmacology and in vitro experiments.

Sepsis-related acute respiratory distress syndrome (ARDS) has a high mortality rate, and no effective treatment is available currently. Quercetin is a natural plant product with many pharmacological activities, such as antioxidative, anti-apoptotic, and anti-inflammatory effects. This study aimed to elucidate the protective mechanism of quercetin against sepsis-related ARDS. In this study, network pharmacology and in vitro experiments were used to investigate the underlying mechanisms of quercetin against sepsis-related ARDS. Core targets and signaling pathways of quercetin against sepsis-related ARDS were screened and were verified by in vitro experiments. A total of 4,230 targets of quercetin, 360 disease targets of sepsis-related ARDS, and 211 intersection targets were obtained via database screening. Among the 211 intersection targets, interleukin-6 (IL-6), tumor necrosis factor (TNF), albumin (ALB), AKT serine/threonine kinase 1 (AKT1), and interleukin-1β (IL-1β) were identified as the core targets. A Gene Ontology (GO) enrichment analysis revealed 894 genes involved in the inflammatory response, apoptosis regulation, and response to hypoxia. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis identified 106 pathways. After eliminating and generalizing, the hypoxia-inducible factor-1 (HIF-1), TNF, nuclear factor-κB (NF-κB), and nucleotide-binding and oligomerization domain (NOD)-like receptor signaling pathways were identified. Molecular docking revealed that quercetin had good binding activity with the core targets. Moreover, quercetin blocked the HIF-1, TNF, NF-κB, and NOD-like receptor signaling pathways in lipopolysaccharide (LPS)-induced murine alveolar macrophage (MH-S) cells. It also suppressed the inflammatory response, oxidative reactions, and cell apoptosis. Quercetin ameliorates sepsis-related ARDS by binding to its core targets and blocking the HIF-1, TNF, NF-κB, and NOD-like receptor signaling pathways to reduce inflammation, cell apoptosis, and oxidative stress.

Antioxidant and anti-inflammatory activities of Lespedeza cuneata in Coal fly ash-induced murine alveolar macrophage cells

Lespedeza cuneata (LC) is a perennial plant used in herbal medicine to treat numerous diseases, including prostatic hyperplasia, diabetes, early atherosclerosis, and hematuria. Reference collections of bioactive compounds of LC are crucial for the determination of their pharmacological properties. However, little is known regarding its anti-oxidative and anti-inflammatory effects in alveolar macrophage (MH-S) cells. This study examined whether LC can inhibit reactive oxygen species and Coal fly ash (CFA) induced inflammation in MH-S cells. The anti-oxidative effects of LC were evaluated using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays, anti-inflammatory effects were examined using nitric oxide (NO) assay, and cytotoxicity was analyzed using methyl thiazolyl tetrazolium assay. The expression of inflammatory cytokine genes was assessed through a reverse-transcription polymerase chain reaction. Our results revealed that LC exhibited high radical scavenging activity and a dose-dependent (7.8–1,000 μg/mL) inhibition of oxidation as compared to ascorbic acid and Trolox. It also inhibited CFA-induced NO production in MH-S cells. Moreover, it suppressed the CFA exposure-mediated expression of pro-inflammatory mediators and cytokines, including inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), interleukin (IL)-1β, IL-6, and tumor necrosis factor-α. These results suggest that LC is a potent antioxidant and anti-inflammatory agent that can be useful as a nutraceutical product.

Advancements in salbutamol sulphate formulation: Spray-drying technique for the production of porous particles with enhanced properties for inhalation drug delivery

A fast, simple and cost-effective technique has been used to produce spray-drying porous particles of salbutamol sulfate (SS) for inhalation drug delivery. The particles were produced using water as solvent and ammonium bicarbonate as pore-forming agent. A full factorial experimental design (24) with a central point was used to evaluate the influence of process parameters (drying air inlet temperature, atomization air volume flowrate, feed volume flowrate and the pore-forming agent concentration) on process yield, moisture content, densities and particle size. In addition, particle morphology, in-vitro aerosolization properties, stability and cytotoxicity of selected samples were studied. Within the experimental design parameters window, it was shown that the highest inlet temperature and pore-forming agent concentration were the factors that more affected the process yield and tap density values. Particles with the lowest tap densities values exhibited porous morphology. In addition, the pore-forming agent concentration proved to be the most significant variable affecting particle size. The highest pore-forming agent concentration, the largest particle size. The porous particles exhibit remarkable aerosolization performance, surpassing the performance of previously reported SS porous particles and a commercial formulation. These powders showed a high process yield and the absence of ammonium bicarbonate in the final product, as confirmed by FT-IR. Furthermore, the powders presented good stability even over long periods of time and did not exhibit cytotoxicity on the murine alveolar macrophage cell line RAW 264.7.

93 Linking the Molecular Mechanisms of Alveolar Macrophage Cell Death Induced by Inhaled Nanoparticles with the Subsequent Pathological Outcome

Abstract Background Carbon Nanomaterials (CNM) get released into the environment as combustion by-products and engineered materials. Our previous work has shown that inhalation of CNMs differing in shape, such as spherical carbon nanoparticles (CNPs) or fiber-shaped nanotubes (CNTs) triggers different response pattern ranging from acute and resolving to persistent and chronic lung inflammation. Furthermore, our cell and mouse data showed that, particularly rigid, multi-walled nanotubes (MWCNTs) can cell-specifically and persistently kill alveolar macrophages (AM). Here we hypothesize that the AM death pathway determines the fate of lung inflammation, as acute or chronic. Results Exposure of the murine AM cell line MH-S to MWCNT led to significant decrease of cell viability in a dose-dependent manner (IC50: 10±5 μg/ml). In comparison, CNPs showed relatively low toxicity (IC50: >200 ug/ml) to MH-S cells. Also in contrast to hardly detectable apoptosis (cleaved-Caspase3), immunoblot and -fluorescence analysis demonstrated significant induction of LC3II, a central protein in the autophagy pathway, 12h after MWCNT treatment. The MWCNT triggered cell death response from BMDM-derived AM-like cells however, did not differ between LC3B-/- and wt mice, indicating the autophagy pathway as dispensable. In contrast, inhibition of lysosomal Cathepsins via K777, rescued MWCNT induced cell death of either MH-S or AM-like cells suggesting lysosomal Cathepsins as key player in AM cell death. Conclusion Lysosomal damage with subsequent Cathepsin activity seem a central key event in MWCNT triggered AM cell death. Current studies investigate the relevance of Cathepsins for the inflammatory consequences of CNT triggered AM cell death.

Inhibition of STAT3 phosphorylation by colchicine regulates NLRP3 activation to alleviate sepsis-induced acute lung injury.

The pharmacotherapeutic mechanism of colchicine, a tricyclic, lipid-soluble alkaloid extracted from the plant of the Lily family Colchicum autumnale, has not been fully understood in diverse disorders, including sepsis-induced acute lung injury (ALI). The study aimed at exploring the impact of colchicine on sepsis-induced ALI and the relevant mechanisms. Colchicine significantly attenuated ALI in mice caused by sepsis by alleviating respiratory dysfunction and pulmonary edema in mice, inhibiting NLRP3 inflammasome formation, and reducing oxidative stress, pyroptosis, and apoptosis of murine alveolar macrophage (J774A.1) cells. The targets of colchicine were predicted in the superPRED database and intersected with the differentially expressed genes in the GSE5883 and GSE129775 datasets. The major targets were subjected to protein-protein interaction network generation and Kyoto Encyclopedia of Genes and Genomes enrichment analysis. It was thus found that colchicine inhibited STAT3 phosphorylation but did not alter STAT3 total protein expression. Phosphorylated STAT3 recruited EP300 to form a complex to promote histone H3 acetylation and histone H4 acetylation of NLRP3 promoter, leading to pyroptosis of J774A.1 cells. In conclusion, inhibition of STAT3 phosphorylation by colchicine represses NLRP3 promoter acetylation via the STAT3/EP300 complex, thereby alleviating ALI caused by sepsis.

Protection against influenza-induced Acute Lung Injury (ALI) by enhanced induction of M2a macrophages: possible role of PPARγ/RXR ligands in IL-4-induced M2a macrophage differentiation.

Many respiratory viruses cause lung damage that may evolve into acute lung injury (ALI), a cytokine storm, acute respiratory distress syndrome, and ultimately, death. Peroxisome proliferator activated receptor gamma (PPARγ), a member of the nuclear hormone receptor (NHR) family of transcription factors, regulates transcription by forming heterodimers with another NHR family member, Retinoid X Receptor (RXR). Each component of the heterodimer binds specific ligands that modify transcriptional capacity of the entire heterodimer by recruiting different co-activators/co-repressors. However, the role of PPARγ/RXR ligands in the context of influenza infection is not well understood. PPARγ is associated with macrophage differentiation to an anti-inflammatory M2 state. We show that mice lacking the IL-4Rα receptor, required for M2a macrophage differentiation, are more susceptible to mouse-adapted influenza (A/PR/8/34; “PR8”)-induced lethality. Mice lacking Ptgs2, that encodes COX-2, a key proinflammatory M1 macrophage mediator, are more resistant. Blocking the receptor for COX-2-induced Prostaglandin E2 (PGE2) was also protective. Treatment with pioglitazone (PGZ), a PPARγ ligand, increased survival from PR8 infection, decreased M1 macrophage gene expression, and increased PPARγ mRNA in lungs. Conversely, conditional knockout mice expressing PPARγ-deficient macrophages were significantly more sensitive to PR8-induced lethality. These findings were extended in cotton rats: PGZ blunted lung inflammation and M1 cytokine gene expression after challenge with non-adapted human influenza. To study mechanisms by which PPARγ/RXR transcription factors induce canonical M2a genes, WT mouse macrophages were treated with IL-4 in the absence or presence of rosiglitazone (RGZ; PPARγ ligand), LG100754 (LG; RXR ligand), or both. IL-4 dose-dependently induced M2a genes Arg1, Mrc1, Chil3, and Retnla. Treatment of macrophages with IL-4 and RGZ and/or LG differentially affected induction of Arg1 and Mrc1 vs. Chil3 and Retnla gene expression. In PPARγ-deficient macrophages, IL-4 alone failed to induce Arg1 and Mrc1 gene expression; however, concurrent treatment with LG or RGZ + LG enhanced IL-4-induced Arg1 and Mrc1 expression, but to a lower level than in WT macrophages, findings confirmed in the murine alveolar macrophage cell line, MH-S. These findings support a model in which PPARγ/RXR heterodimers control IL-4-induced M2a differentiation, and suggest that PPARγ/RXR agonists should be considered as important tools for clinical intervention against influenza-induced ALI.

Antibiotic-Loaded Amphiphilic Chitosan Nanoparticles Target Macrophages and Kill an Intracellular Pathogen.

In this work, levofloxacin (LVX), a third-generation fluoroquinolone antibiotic, is encapsulated within amphiphilic polymeric nanoparticles of a chitosan-g-poly(methyl methacrylate) produced by self-assembly and physically stabilized by ionotropic crosslinking with sodium tripolyphosphate. Non-crosslinked nanoparticles display a size of 29nm and a zeta-potential of +36mV, while the crosslinked counterparts display 45nm and +24mV, respectively. The cell compatibility, uptake, and intracellular trafficking are characterized in the murine alveolar macrophage cell line MH-S and the human bronchial epithelial cell line BEAS-2B in vitro. Internalization events are detected after 10min and the uptake is inhibited by several endocytosis inhibitors, indicating the involvement of complex endocytic pathways. In addition, the nanoparticles are detected in the lysosomal compartment. Then, the antibacterial efficacy of LVX-loaded nanoformulations (50% w/w drug content) is assessed in MH-S and BEAS-2B cells infected with Staphylococcus aureus and the bacterial burden is decreased by 49% and 46%, respectively. In contrast, free LVX leads to a decrease of 8% and 5%, respectively, in the same infected cell lines. Finally, intravenous injection to a zebrafish larval model shows that the nanoparticles accumulate in macrophages and endothelium and demonstrate the promise of these amphiphilic nanoparticles to target intracellular infections.

Effect of Acinetobacter lwoffii on the modulation of macrophage activation and asthmatic inflammation.

Although lung macrophages are directly exposed to external stimuli, their exact immunologic roles in asthma are still largely unknown. The aim of this study was to investigate the anti-asthmatic effect of Acinetobacter lwoffii in terms of lung macrophage modulation. Six-week-old female BALB/c mice were sensitized and challenged with ovalbumin (OVA) with or without intranasal administration of A. lwoffii during the sensitization period. Airway hyperresponsiveness and inflammation were evaluated. Using flow cytometry, macrophages were subclassified according to their activation status. In the in vitro study, a murine alveolar macrophage cell line (MH-S) treated with or without A. lwoffii before IL-13 stimulation were analysed by quantitative RT-PCR. In a murine asthma model, the number of inflammatory cells, including macrophages and eosinophils, decreased in mice treated with A. lwoffii (A. lwoffii/OVA group) compared with untreated mice (OVA group). The enhanced expression of MHCII in macrophages in the OVA group was decreased by A. lwoffii treatment. M2 macrophage subtypes were significantly altered. A. lwoffii treatment decreased CD11b+ M2a and CD11b+ M2c macrophages, which showed strong positive correlations with Th2 cells, ILC2 and eosinophils. In contrast, CD11b+ M2b macrophages were significantly increased by A. lwoffii treatment and showed strong positive correlations with ILC1 and ILC3. In vitro, A. lwoffii down-regulated the expression of M2 markers related but up-regulated those related to M2b macrophages. Intranasal A. lwoffii exposure suppresses asthma development by suppressing the type 2 response via modulating lung macrophage activation, shifting M2a and M2c macrophages to M2b macrophages.

Mycoplasma ovipneumoniae induces caspase-8-dependent extrinsic apoptosis and p53- and ROS-dependent intrinsic apoptosis in murine alveolar macrophages

ABSTRACT Mycoplasma ovipneumoniae (MO) is a principle causative agent of chronic respiratory disease in ruminants, including sheep, goats, and deer, posing a great threat to the ruminant industry worldwide. However, the pathogenesis of MO infection still remains not well understood and needs further clarification. Here we report a time-dependent apoptosis in cultured murine alveolar macrophage (MH-S) cell lines in response to MO infection in vitro. Mechanistically, MO infection activated apoptosis in MH-S cells through caspase-8-dependent extrinsic pathway and through tumor protein 53 (p53)- and reactive oxygen species (ROS)-dependent intrinsic mitochondrial pathways. Moreover, MO infection promoted both transcription and translation of proinflammatory cytokine genes including interleukin-1β (IL-1β), IL-18, and tumor necrosis factor-α (TNF-α), in a caspase-8-, p53-, and ROS-dependent manner, implying a potential link between MO-induced inflammation and apoptotic cell death. Collectively, our results suggest that MO infection induces the activation of extrinsic and intrinsic apoptotic pathways in cultured MH-S cells, which is related to upregulated expression of proinflammatory cytokines. Our findings will contribute to the elucidation of pathogenesis in MO infection and provide valuable reference for the development of new strategies for controlling MO infection.

PI3K/ NF-κB-dependent TNF-α and HDAC activities facilitate LPS-induced RGS10 suppression in pulmonary macrophages

Regulator of G-protein signaling 10 (RGS10) is a member of the superfamily of RGS proteins that canonically act as GTPase activating proteins (GAPs). RGS proteins accelerate GTP hydrolysis on the G-protein α subunits and result in termination of signaling pathways downstream of G protein-coupled receptors. Beyond its GAP function, RGS10 has emerged as an anti-inflammatory protein by inhibiting LPS-mediated NF-κB activation and expression of inflammatory cytokines, in particular TNF-α. Although RGS10 is abundantly expressed in resting macrophages, previous studies have shown that RGS10 expression is suppressed in macrophages following Toll-like receptor 4 (TLR4) activation by LPS. However, the molecular mechanism by which LPS induces Rgs10 silencing has not been clearly defined. The goal of the current study was to determine whether LPS silences Rgs10 expression through an NF-κB-mediated proinflammatory mechanism in pulmonary macrophages, a unique type of innate immune cells. We demonstrate that Rgs10 transcript and RGS10 protein levels are suppressed upon LPS treatment in the murine MH-S alveolar macrophage cell line. We show that pharmacological inhibition of PI3K/ NF-κB/p300 (NF-κB co-activator)/TNF-α signaling cascade and the activities of HDAC (1–3) enzymes block LPS-induced silencing of Rgs10 in MH-S cells as well as microglial BV2 cells and BMDMs. Further, loss of RGS10 generated by using CRISPR/Cas9 amplifies NF-κB phosphorylation and inflammatory gene expression following LPS treatment in MH-S cells. Together, our findings strongly provide critical insight into the molecular mechanism underlying RGS10 suppression by LPS in pulmonary macrophages.

Efficacy of SPG-ODN 1826 Nanovehicles in Inducing M1 Phenotype through TLR-9 Activation in Murine Alveolar J774A.1 Cells: Plausible Nano-Immunotherapy for Lung Carcinoma.

Alveolar macrophages are the first line of defense against intruding pathogens and play a critical role in cancer immunology. The Toll-like receptor (TLR) family mediates an important role in recognizing and mounting an immune response against intruding microbes. TLR-9 is a member of the intracellular TLR family, which recognizes unmethylated CG motifs from the prokaryotic genome. Upon its activation, TLR-9 triggers downstream of the MyD-88-dependent transcriptional activation of NF-κB, and subsequently results in abundant inflammatory cytokines expression that induces a profound inflammatory milieu. The present exploratory investigation aimed at elucidating the potency of schizophyllan for entrapping ODN 1826 (SPG-ODN 1826)-mediated stimulation of TLR-9 in provoking an inflammatory-type response in murine alveolar macrophages. Schizophyllan (SPG), a representative of the β-glucan family, was used in the present study as a nanovehicle for endosomal trafficking of CpG ODN 1826. TEM analysis of SPG-ODN 1826 nanovehicles revealed that the prepared nanovehicles are spherical and have an average size of about 100 nm. Interestingly, SPG-ODN 1826 nanovehicles were competent in delivering their therapeutic payload within endosomes of murine alveolar macrophage (J774A.1) cells. Exposure of these nanovehicles within LPS stimulated J774A.1, resulted in a significant provocation of reactive oxygen species (ROS) (p < 0.01) in comparison to CpG ODN 1826 alone. Moreover, the formulated nanovehicles succeeded in generating a profound Th1-based cytokine profile constituted by enhanced expression of IFN-γ (p < 0.001) and IL-1β (p < 0.001) inflammatory cytokines. These findings clearly indicated the immunostimulatory potential of SPG-ODN 1826 nanovehicles for inducing the Th1-type phenotype, which would certainly assist in skewing M2 phenotype into the much-desired M1 type during lung cancer.

Exosomes derived from LPS-induced MHs cells prompted an inflammatory response in sepsis-induced acute lung injury

Exosome is a novel tool with an essential role in cell communication. However, its role in the pathogenesis of sepsis-induced acute lung injury is currently unknown. Here, we first found that lipopolysaccharide (LPS) could up-regulate the expression of pro-inflammatory cytokines and promote exosomes release in the murine alveolar macrophage cell line (MHs cells). Moreover, we found MHs cells derived exosomes also maintain the pro-inflammatory effect after LPS stimulation. Treating with hydrochloride hydrate (GW4869) could dose-dependently downregulated the release of exosomes and inhibited the upregulation of inflammatory cytokines in MHs cells with LPS treatment. Also, we further identified GW4869 administration induced the remission of histopathologic changes, the reduction of pro-inflammatory cytokines in lung tissue, and inhibit serum exosomes release. These results indicate that the downregulation of exosome release by GW4869 might protect lung tissue from LPS induced injury through the suppression of excessive inflammatory responses, suggesting its potential therapeutic effects on sepsis-induced acute lung injury.

Nicotine in E-Cigarettes Dysregulates Pulmonary Inflammation and MMP-12 Expression without Effecting Respiratory Syncytial Virus Virulence

The safety of electronic cigarettes (e-cigarettes) is a major topic of discussion. The key goals of this study were to examine the contents of e-cigarette vapor and determine if nicotine altered inflammatory responses against respiratory syncytial virus (RSV) infection. E-cigarette vapor was passed through a hollow 3D-model of an adult lung, and gas chromatography detected over 50 compounds passed through the 3D model, including nicotine, propylene glycol (PG), ethanol, methanol, and diacetyl. The murine alveolar macrophage cell line MH-S cells were exposed to nicotine and e-cigarette vapor with and without nicotine. Nicotine significantly induced the expression of matrix metalloprotease (Mmp) 12 and reduced expression of Ifnβ and Tnfα. To examine the role of nicotine in lung defense against RSV infection, A/J mice were exposed to PBS, e-cigarette vapor with and without nicotine for 2 months before RSV infection. E-cigarette vapor did not influence RSV infection-induced animal weight loss, RSV infectivity, airway hyperresponsiveness during methacholine challenge, or immune cell infiltration into the lungs. However, e-cigarette vapor containing nicotine enhanced obstruction and induced secretion of MMP12 and reduced levels of Ifnβ and TNFα. In conclusion, nicotine in vaping products modulates immune responses that may impact the lungs during a respiratory infection.

MiR-23b Attenuates LPS-Induced Inflammatory Responses in Acute Lung Injury via Inhibition of HDAC2

Inflammatory responses play significant role in infectious etiology-induced acute lung injury (ALI). Histone deacetylase 2 is found to be essential and stimulated in lipopolysaccharide (LPS)-induced ALI by regulating proinflammatory cytokines. miR-23b has been demonstrated to be downregulated in LPS-induced inflammatory injury. In this study, we aimed to explore the interaction between miR-23b and HDAC2 and their function in LPS-induced ALI. LPS treatment was induced on murine alveolar macrophage cell line MH-S. Level of miR-23b and HDAC2 were determined by real-time PCR or Western blot. Proinflammatory cytokines expression and secretion were detected by real-time PCR and ELISA assay. The levels of miR-23b and HDAC2 were manipulated by transient transfection of miRNA mimics, shRNA or overexpression vector. The interaction between miR-23b and HDAC2 were tested by Luciferase reporter assay. LPS treatment inhibited miR-23b expression, while increased HDAC2 level in MH-S cells. Proinflammatory cytokines were stimulated by LPS treatment. Knockdown of HDAC2 or overexpression of miR-23b significantly repressed the expression of proinflammatory cytokines induced by LPS. miR-23b could suppress HDAC2 expression by directly targeting to its mRNA. LPS treatment stimulated the inflammatory responses in macrophages through inhibition of miR-23b, enhanced HDAC2 expression and inducing the expression of its downstream targets TNF-α, IL-6, and IL-1β. Overexpression of miR-23b was sufficient to suppress inflammatory responses by targeting HDAC2, making it a promising therapeutic target to ALI treatment.

Size-Dependent Phagocytic Uptake and Immunogenicity of Gliadin Nanoparticles.

The main objective of the present study was to investigate the hemo and immune compatibility of gliadin nanoparticles as a function of particle size. Gliadin nanoparticles of different size were prepared using a modified antisolvent nanoprecipitation method. The hemolytic potential of gliadin nanoparticles was evaluated using in vitro hemolysis assay. Phagocytic uptake of gliadin nanoparticles was studied using rat polymorphonuclear (PMN) leukocytes and murine alveolar peritoneal macrophage (J774) cells. In vivo immunogenicity of gliadin nanoparticles was studied following subcutaneous administration in mice. Gliadin nanoparticles were non-hemolytic irrespective of particle size and hence compatible with blood components. In comparison to positive control zymosan, gliadin nanoparticles with a size greater than 406 ± 11 nm showed higher phagocytic uptake in PMN cells, while the uptake was minimal with smaller nanoparticles (127 ± 8 nm). Similar uptake of gliadin nanoparticles was observed in murine alveolar peritoneal macrophages. Anti-gliadin IgG antibody titers subsequent to primary and secondary immunization of gliadin nanoparticles in mice were in the increasing order of 406 ± 11 nm < 848 ± 20 nm < coarse suspension). On the other hand, gliadin nanoparticles of 127 ± 8 nm in size did not elicit immunogenic response. Phagocytosis and immunogenicity of gliadin nanoparticles are strongly influenced by particle size. The results of this study can provide useful information for rational design of protein-based nanomaterials in drug delivery applications.

MicroRNA-31-5p Exacerbates Lipopolysaccharide-Induced Acute Lung Injury via Inactivating Cab39/AMPKα Pathway.

Acute lung injury (ALI) and the subsequent acute respiratory distress syndrome remain devastating diseases with high mortality rates and poor prognoses among patients in intensive care units. The present study is aimed at investigating the role and underlying mechanisms of microRNA-31-5p (miR-31-5p) on lipopolysaccharide- (LPS-) induced ALI. Mice were pretreated with miR-31-5p agomir, antagomir, and their negative controls at indicated doses for 3 consecutive days, and then they received a single intratracheal injection of LPS (5 mg/kg) for 12 h to induce ALI. MH-S murine alveolar macrophage cell lines were cultured to further verify the role of miR-31-5p in vitro. For AMP-activated protein kinase α (AMPKα) and calcium-binding protein 39 (Cab39) inhibition, compound C or lentiviral vectors were used in vivo and in vitro. We observed an upregulation of miR-31-5p in lung tissue upon LPS injection. miR-31-5p antagomir alleviated, while miR-31-5p agomir exacerbated LPS-induced inflammation, oxidative damage, and pulmonary dysfunction in vivo and in vitro. Mechanistically, miR-31-5p antagomir activated AMPKα to exert the protective effects that were abrogated by AMPKα inhibition. Further studies revealed that Cab39 was required for AMPKα activation and pulmonary protection by miR-31-5p antagomir. We provide the evidence that endogenous miR-31-5p is a key pathogenic factor for inflammation and oxidative damage during LPS-induced ALI, which is related to Cab39-dependent inhibition of AMPKα.

NLRC5 negatively regulates inflammatory responses in LPS-induced acute lung injury through NF-κB and p38 MAPK signal pathways

Acute lung injury is an acute inflammatory disease with high morbidity rate and high mortality rate. However, there is still no effective clinical treatment to date. Our previous studies found that NLRC5 was significantly increased in acute liver injury model induced by LPS to reduce the secretion of IL-6 and TNF-α. Nevertheless, there is no report on the role of NLRC5 in regulating the development of acute lung injury. In this study we successfully established a model of acute lung injury induced by tracheal instillation of LPS in mice, and found NLRC5 expression was apparently elevated in mouse lung tissue and primary alveolar macrophages. NLRC5 overexpression negatively regulated secretion of inflammatory cytokines in murine alveolar macrophage cells through NF-κB and p38 MAPK pathway inhibition. There is a positively feedback between NLRC5 and NF-κB or p38 MAPK pathway. This study may provide some new ideas for clinical prevention of lung injury.