Bronchioalveolar Lavage Fluid Research Articles

Comparative Preclinical Pharmacokinetics and Disposition of Favipiravir Following Pulmonary and Oral Administration as Potential Adjunct Therapy Against Airborne RNA Viruses.

Favipiravir is administered orally, even against airborne RNA viruses, in a loading-dose/maintenance dose regimen. We investigated whether-(a) pulmonary delivery of favipiravir would generate high concentrations in the luminal side of the respiratory tract; and (b) avoiding first-pass metabolism by the liver by inhaled drug would generate comparable pharmacokinetics (PK) with doses significantly smaller than the oral maintenance dose. A dry powder inhalation (DPI) of favipiravir formulated by mixing with Inhalac 400® was prepared and characterized. Inhalations of ~ 120µg dose strength, with or without a prior oral loading dose were administered to mice. Comparator mice received human-equivalent oral doses (3mg). Three mice per sampling time point were sacrificed and favipiravir concentrations in the blood plasma, bronchio-alveolar lavage fluid (BALF) and lung tissue homogenate determined by HPLC. One-compartment PK modeling of concentration-time data indicated that the area under the curve (AUC0-24h) generated in the BALF recovered from mice receiving inhalations of ~ 1/25th of the oral dose subsequent to an oral loading dose was 86.72 ± 4.48µg⋅mL-1⋅h. This was consistently higher than the AUC observed in the BALF of orally-dosed mice (56.71 ± 53.89µgmL-1⋅h). In blood serum, the respective values of AUC were 321.55 ± 124.91 and 354.71 ± 99.60µg⋅mL-1⋅h. Pulmonary delivery of significantly smaller doses of favipiravir generates meaningful drug disposition and pharmacokinetics at the site of respiratory viral infections. We provide the rationale for designing a self-administered, non-invasive, low-cost, targeted drug delivery system against airborne RNA virus infection.

Changes in respiratory infection trends during the COVID-19 pandemic in patients with haematologic malignancy

BackgroundThe coronavirus disease 2019 (COVID-19) pandemic has changed respiratory infection patterns globally. However, its impact on community-acquired pneumonia (CAP) in high-risk patients with haematological malignancies (HM) is uncertain. We aimed to examine how community-acquired pneumonia aetiology in patients with haematological malignancies changed during the COVID-19 pandemic.MethodsThis was a retrospective study that included 524 patients with haematological malignancies hospitalised with community-acquired pneumonia between March 2018 and February 2022. Patients who underwent bronchoscopy within 24 h of admission to identify community-acquired pneumonia aetiology were included. Data on patient characteristics, laboratory findings, and results of bronchioalveolar lavage fluid cultures and polymerase chain reaction tests were analysed and compared to identify changes and in-hospital mortality risk factors.ResultsPatients were divided into the ‘pre-COVID-19 era’ (44.5%) and ‘COVID-19 era’ (55.5%) groups. The incidence of viral community-acquired pneumonia significantly decreased in the COVID-19 era, particularly for influenza A, parainfluenza, adenovirus, and rhinovirus (pre-COVID-19 era vs. COVID-19 era: 3.0% vs. 0.3%, P = 0.036; 6.5% vs. 0.7%, P = 0.001; 5.6% vs. 1.4%, P = 0.015; and 9.5% vs. 1.7%, P < 0.001, respectively), whereas that of bacterial, fungal, and unknown community-acquired pneumonia aetiologies remain unchanged. Higher Sequential Organ Failure Assessment scores and lower platelet counts correlated with in-hospital mortality after adjusting for potential confounding factors.ConclusionsIn the COVID-19 era, the incidence of community-acquired pneumonia with viral aetiologies markedly decreased among patients with haematological malignancies, with no changes in the incidence of bacterial and fungal pneumonia. Further studies are required to evaluate the impact of COVID-19 on the prognosis of patients with haematological malignancies and community-acquired pneumonia.

In Vivo Immune-Modulatory Activity of Lefamulin in an Influenza Virus A (H1N1) Infection Model in Mice

Lefamulin is a first-in-class systemic pleuromutilin antimicrobial and potent inhibitor of bacterial translation, and the most recent novel antimicrobial approved for the treatment of community-acquired pneumonia (CAP). It exhibits potent antibacterial activity against the most prevalent bacterial pathogens that cause typical and atypical pneumonia and other infectious diseases. Early studies indicate additional anti-inflammatory activity. In this study, we further investigated the immune-modulatory activity of lefamulin in the influenza A/H1N1 acute respiratory distress syndrome (ARDS) model in BALB/c mice. Comparators included azithromycin, an anti-inflammatory antimicrobial, and the antiviral oseltamivir. Lefamulin significantly decreased the total immune cell infiltration, specifically the neutrophils, inflammatory monocytes, CD4+ and CD8+ T-cells, NK cells, and B-cells into the lung by Day 6 at both doses tested compared to the untreated vehicle control group (placebo), whereas azithromycin and oseltamivir did not significantly affect the total immune cell counts at the tested dosing regimens. Bronchioalveolar lavage fluid concentrations of pro-inflammatory cytokines and chemokines including TNF-α, IL-6, IL-12p70, IL-17A, IFN-γ, and GM-CSF were significantly reduced, and MCP-1 concentrations were lowered (not significantly) by lefamulin at the clinically relevant ‘low’ dose on Day 3 when the viral load peaked. Similar effects were also observed for oseltamivir and azithromycin. Lefamulin also decreased the viral load (TCID50) by half a log10 by Day 6 and showed positive effects on the gross lung pathology and survival. Oseltamivir and lefamulin were efficacious in the suppression of the development of influenza-induced bronchi-interstitial pneumonia, whereas azithromycin did not show reduced pathology at the tested treatment regimen. The observed anti-inflammatory and immune-modulatory activity of lefamulin at the tested treatment regimens highlights a promising secondary pharmacological property of lefamulin. While these results require confirmation in a clinical trial, they indicate that lefamulin may provide an immune-modulatory activity beyond its proven potent antibacterial activity. This additional activity may benefit CAP patients and potentially prevent acute lung injury (ALI) and ARDS.

Adenophora Stricta Root Extract Alleviates Airway Inflammation in Mice with Ovalbumin-Induced Allergic Asthma.

Adenophora stricta Miq. (Campanulaceae family) is a traditional herb used for relieving cough and phlegm in East Asia. This study explored the effects of A. stricta root extract (AsE) in ovalbumin (OVA)-induced allergic asthma and lipopolysaccharide (LPS)-stimulated macrophages. Administration of 100-400 mg/kg AsE dose-dependently decreased pulmonary congestion and suppressed the reduction of alveolar surface area in mice with OVA-mediated allergic asthma. Histopathological analysis of lung tissue and cytological analysis of bronchioalveolar lavage fluid showed that AsE administration significantly attenuated inflammatory cell infiltration into the lungs. In addition, AsE also alleviated OVA-specific immunoglobulin E, interleukin (IL)-4, and IL-5 production, which are essential for OVA-dependent activation of T helper 2 lymphocytes. In Raw264.7 macrophage cells, AsE significantly blocked nitric oxide, tumor necrosis factor-α, IL-1β, IL-6, and monocyte chemoattractant factor-1 production in response to LPS. Results from an immunoblot assay revealed that AsE inhibited the phosphorylation of c-jun N-terminal kinase, inhibitory-κB kinase α/β, and p65 in LPS-stimulated cells. Furthermore, 2-furoic acid, 5-hydroxymethylfurfural, and vanillic acid 4-β-D-glucopyranoside in AsE were shown to inhibit the production of proinflammatory mediators by LPS. Taken together, the present results suggest that A. stricta root will be a useful herb for relieving allergic asthma through managing airway inflammation.

Abstract 5104: Targeting IL-1B synergizes with PD-1 blockade for enhanced T and B cell immune responses and inhibition of early lung cancer development

Abstract Early immunotherapy with inhibitors of immune checkpoints such as PD-1 has revolutionized lung adenocarcinoma (LUAD) treatment. Still, many patients do not respond or relapse following PD-1 blockade. Tumor-promoting inflammation, such as that mediated by the pleiotropic cytokine interleukin 1 beta (IL-1B), fosters immunosuppression in the tumor immune microenvironment (TIME). Our group and others showed that IL-1B blockade inhibits lung cancer development. We thus hypothesized that addition of IL-1B blockade to anti-PD-1 treatment may enhance outcomes against LUAD. Using a human-relevant, tobacco-associated, mouse model of LUAD development, we compared the effects of combined PD-1 and IL-1B blockade relative to treatment with single-agents (anti-IL-1B or anti-PD-1) and control antibody on early lung tumor development and the TIME. Drugs (anti-PD-1 + anti-IL-1B, anti-PD-1, anti-IL-1B, control IgG) were administered at end of exposure to the tobacco-specific carcinogen NNK, to evaluate effects on formation of early lesions (preventive), or at 3 months post-NNK (prophylactic) to interrogate LUAD development (8 groups). Comprehensive interrogation of the lung ecosystem and the TIME was performed using deep single-cell RNA-sequencing (scRNA-seq) analysis in a subset of the mice (n = 3 to 4) from each of the 8 groups (n = 31 total; 143,897 cells after stringent quality control). Mice treated with combined PD-1 and IL-1B blockade displayed reduced development of lung tumors when compared to animals treated with anti-IL-1B, anti-PD-1, or control antibodies. Fractions of cytotoxic Cd8+ T cells were conspicuously higher and those of tumor cells and exhausted Cd8+ T cells evidently lower in lungs of mice treated with combined PD-1 and IL-1B blockade relative to monotherapy- or control antibody-treated animals. Igha+ plasma cells were strikingly highest in lungs of mice treated with combined PD-1 and IL-1B blockade and nearly absent in monotherapy- and control-treated groups. Lungs of mice treated with combined PD-1 and IL-1B blockade showed higher fractions of Cd80+/Cd86+ memory B cells and, consistently, T follicular helper T cells, while exhibiting reduced fractions of naïve B and Cd24a+/Tgfb1+ B cells suggestive of enhanced activation of B cell responses by the combinatorial treatment. These effects were, overall, present, or much more pronounced, in animals that were prophylactically treated. Flow cytometry analysis of lung tissues and immune profiling of bronchioalveolar lavage fluid overall confirmed augmented immune cell responses by combined PD-1 and IL-1B blockade. Our findings show that blocking IL-1B synergizes with anti-PD-1 in regression of early tumor cells and reversal of immunosuppression. Combined blockade of PD-1 and IL-1B may be a promising strategy for early treatment of lung cancer that warrants further clinical studies. Citation Format: Warapen Treekitkarnmongkol, Guangchun Han, Zahraa Rahal, Jiping Feng, Ansam Sinjab, Tina Cascone, Christopher S. Stevenson, Cheryl Sweeney, Matt Edwards, Avrum Spira, Junya Fujimoto, Seyed Javad Moghaddam, Linghua Wang, Humam Kadara. Targeting IL-1B synergizes with PD-1 blockade for enhanced T and B cell immune responses and inhibition of early lung cancer development. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5104.

Immunosuppression reduces rAAV2.5T neutralizing antibodies that limit efficacy following repeat dosing to ferret lungs

The efficacy of redosing the recombinant adeno-associated virus (rAAV) vector rAAV2.5T to ferret lung is limited by AAV neutralizing antibody (NAb) responses. While immunosuppression strategies have allowed for systemic rAAV repeat dosing, their utility for rAAV lung-directed gene therapy is largely unexplored. To this end, we evaluated two immunosuppression (IS) strategies to improve repeat dosing of rAAV2.5T to ferret lungs: (1) a combination of three IS drugs (Tri-IS) with broad coverage against cellular and humoral responses (methylprednisolone [MP], azathioprine, and cyclosporine) and (2) MP alone, which is typically used in systemic rAAV applications. Repeat dosing utilized AAV2.5T-SP183-fCFTRΔR (recombinant ferret CFTR transgene), followed 28days later by AAV2.5T-SP183-gLuc (for quantification of transgene expression). Both the Tri-IS and MP strategies significantly improved transgene expression following repeat dosing and reduced AAV2.5T NAb responses in the bronchioalveolar lavage fluid (BALF) and plasma, while AAV2.5T binding antibody subtypes and cellular immune responses by ELISpot were largely unchanged by IS. One exception was the reduction in plasma AAV2.5T binding immunoglobulin G (IgG) in both IS groups. Only the Tri-IS strategy significantly suppressed splenocyte expression of IFNA (interferon α [IFN-α]) and IL4. Our studies suggest that IS strategies may be useful in clinical application of rAAV targeting lung genetic diseases such as cystic fibrosis.

2189. Anti-inflammatory Activity of Lefamulin in a Mouse Model of Influenza Virus H1N1 Infection

Abstract Background Lefamulin (LEF) is a pleuromutilin antibiotic approved by the United States (US) FDA for the treatment of community-acquired bacterial pneumonia in adults. In addition to the potent antibacterial activity, LEF has demonstrated anti-inflammatory activity in an LPS induced lung neutrophilia model in mice. We investigated the anti-inflammatory activity of lefamulin in the H1N1 influenza mouse model in comparison to oseltamivir (OTV) and azithromycin (AZM). Methods Infection was performed in BALB/c mice by intranasal challenge ∼70 pfu influenza virus H1N1 A/PR/8/1934 (Day 0). Treatment with drugs at clinically relevant doses started on Day -1 (LEF 70 mg/kg/day and 110/140 mg/kg/day, s.c., AZM 30 mg/kg/day, i,p. and OTV 20 mg/kg/day p.o.) to Day 6. On Days 3 and 6, bronchioalveolar lavage fluid (BALF) was collected to measure infiltrating lung leukocytes and cytokines. Lung immunopathology following infection was evaluated on Day 6 by gross pathology at termination together with hematoxylin and eosin histopathology. Results In untreated vehicle control animals, the influenza infection progressed as expected with bodyweight loss, increased cell infiltration into the lung and increased levels of TNF-α, IL-6 at day 3 and 6. Treatment with LEF significantly decreased the total immune cell infiltration into the lung by day 6 at both doses tested (Figure Left). Cytokine levels in the BALF were significantly reduced on day 3 when the viral load peaked. Furthermore, LEF showed positive effects on lung gross pathology and survival. Oseltamivir and LEF, at both doses, appeared efficacious in the suppression of the development of influenza-induced bronchi-interstitial pneumonia, whereas azithromycin didn’t show reduced pathology (Figure Right). Anti-inflammatory effects of LEF, AZM and OTV in BALF of H1N1 infected mice infected with influenza virus H1N1. Left: Total lung leukocyte infiltrate following infection on day 0. Bars represent mean ± SEM. Right: Day 6 lung inflammation and degeneration histopathology score. Data are presented as mean histopathology score + SEM (n=10). One-way ANOVA, with Dunnett’s multiple comparisons against the vehicle control treatment was run for each timepoint. * represents significance level of p&amp;lt;0.05. ** indicates p&amp;lt;0.01. Conclusion Lefamulin showed anti-inflammatory treatment following acute influenza virus infection. Following influenza infection LEF was able to significantly reduce lung immunopathology and improve clinical outcome in mice. Results from this experiment were consistent with that observed in the LPS induced lung neutrophilia mouse model. Further studies are warranted to evaluate the immunomodulatory potential of Lefamulin. Disclosures Wolfgang W. Wicha, MSc, Nabriva Therapeutics: Grant/Research Support|Nabriva Therapeutics: Inventor|Nabriva Therapeutics: Employee|Nabriva Therapeutics: Stocks/Bonds Sandy Kimber, PhD, Nabriva Therapeutics: Grant/Research Support Charlotte Cumper, BSc, Nabriva Therapeutics: Grant/Research Support Hon S. Lam, MSc, Nabriva Therapeutics: Grant/Research Support Lorena S. Ballesteros, MSc, Nabriva Therapeutics: Grant/Research Support Christopher Kirkham, PhD, Nabriva Therapeutics: Grant/Research Support Claire Richards, PhD, Nabriva Therapeutics: Grant/Research Support Steven P. Gelone, PharmD, Nabriva Therapeutics: Board Member|Nabriva Therapeutics: Inventor|Nabriva Therapeutics: Employee|Nabriva Therapeutics: Stocks/Bonds|Nabriva Therapeutics: Stocks/Bonds Susanne Paukner, PhD, Nabriva Therapeutics: Inventor|Nabriva Therapeutics: Employee|Nabriva Therapeutics: Stocks/Bonds.

Analyzing proteolytic stability and metabolic hotspots of therapeutic peptides in two rodent pulmonary fluids

Peptides and peptide drug conjugates are emerging modalities to treat pulmonary diseases. Peptides are susceptible to proteolytic cleavage. Expression levels of specific proteases in the lung can be significantly increased in disease state and may lead to exaggerated peptide proteolysis. To support optimization of peptides for inhaled administration, we have recently reported a streamlined high-throughput LC-HRMS protocol to determine enzymatic protease stability of peptides. This method has now been complemented with profiling of peptide metabolic stability in two respiratory fluids, a lung supernatant (lung S9) and a bronchioalveolar lavage fluid (BALF) taken from rats. We have tested a set of 28 peptides with high structural diversity, analyzed the whole data set for formed metabolites, and identified the differences of cleavage pattern in the two test fluids. Comparison of our experimental results and literature-derived cleavage site estimates based on e.g. MEROPS show significant differences for a number of peptides. This indicates the need for an experimental workflow using both protease panels and testing of metabolic stability in lung fluid (BALF) to guide peptide optimization and selection of peptides for inhaled in vivo PK/PD studies in our drug discovery projects.

Immunogenicity and Protective Efficacy of a Recombinant Pichinde Viral-Vectored Vaccine Expressing Influenza Virus Hemagglutinin Antigen in Pigs.

Influenza A virus of swine (IAV-S) is an economically important swine pathogen. The IAV-S hemagglutinin (HA) surface protein is the main target for vaccine development. In this study, we evaluated the feasibility of using the recombinant tri-segmented Pichinde virus (rPICV) as a viral vector to deliver HA antigen to protect pigs against IAV-S challenge. Four groups of weaned pigs (T01–T04) were included in the study. T01 was injected with PBS to serve as a non-vaccinated control. T02 was inoculated with rPICV expressing green fluorescence protein (rPICV-GFP). T03 was vaccinated with rPICV expressing the HA antigen of the IAV-S H3N2 strain (rPICV-H3). T04 was vaccinated with the recombinant HA protein antigen of the same H3N2 strain. Pigs were vaccinated twice at day 0 and day 21 and challenged at day 43 by intra-tracheal inoculation with the homologous H3N2 IAV-S strain. After vaccination, all pigs in T03 and T04 groups were seroconverted and exhibited high titers of plasma neutralizing antibodies. After challenge, high levels of IAV-S RNA were detected in the nasal swabs and bronchioalveolar lavage fluid of pigs in T01 and T02 but not in the T03 and T04 groups. Similarly, lung lesions were observed in T01 and T02, but not in the T03 and T04 groups. No significant difference in terms of protection was observed between the T03 and T04 group. Collectively, our results demonstrate that the rPICV-H3 vectored vaccine elicited protective immunity against IAV-S challenge. This study shows that rPICV is a promising viral vector for the development of vaccines against IAV-S.

Adenophora Stricta Root Extract Protects Lung Injury from Exposure to Particulate Matter 2.5 in Mice

Chronic exposure of particulate matter of less than 2.5 μm (PM2.5) has been considered as one of the major etiologies for various respiratory diseases. Adenophora stricta Miq. is a medicinal herb that has been used for treating respiratory diseases in East Asia. The present study investigated the effect of A. stricta root extract (AsE) on PM2.5-induced lung injury in mice. Oral administration of 100–400 mg/kg AsE for 10 days significantly reduced the PM2.5-mediated increase in relative lung weight, but there was no difference in body weight with AsE administration. In addition, AsE dose-dependently decreased congested region of the lung tissue, prevented apoptosis and matrix degradation, and alleviated mucus stasis induced by PM2.5. Moreover, cytological analysis of bronchioalveolar lavage fluid revealed that AsE significantly inhibited the infiltration of immune cells into the lungs. Consistently, AsE also decreased expression of proinflammatory cytokines and chemokines in lung tissue. Furthermore, AsE administration blocked reactive oxygen species production and lipid peroxidation through attenuating the PM2.5-dependent reduction of antioxidant defense system in the lungs. Therefore, A. stricta root would be a promising candidate for protecting lung tissue from air pollution such as PM2.5.

Synergistic effect of roflumilast with dexamethasone in a neutrophilic asthma mouse model.

Asthma is a chronic airway inflammatory disease with heterogeneous features. Most cases of asthma are steroid sensitive, but 5%-10% are unresponsive to steroids, leading to challenges in treatment. Neutrophilic asthma is steroid-resistant and characterized by the absence or suppression of the T-helper type II (TH 2) process and an increase in the TH 1 and/or TH 17 process. Roflumilast (ROF) has anti-inflammatory effects and has been used to treat chronic inflammatory airway diseases, such as chronic pulmonary obstructive disease. It is unclear whether ROF may have a therapeutic role in neutrophilic asthma. In this study, we investigated the synergistic effect of ROF with dexamethasone (DEX) in a neutrophilic asthma mouse model. C57BL/6 female mice sensitized to ovalbumin (OVA) were exposed to five intranasal OVA treatments and three intranasal lipopolysaccharide (LPS) treatments for an additional 10days. During the intranasal OVA challenge, ROF was administrated orally, and DEX was injected intraperitoneally. Protein, pro-inflammatory cytokines, inflammatory cytokines and other suspected markers were identified by enzyme-linked immunosorbent assay, real-time polymerase chain reaction, and western blot. Following exposure to LPS in OVA-induced asthmatic mice, neutrophil predominant airway inflammation rather than eosinophil predominant inflammation was observed, with increases in airway hyperresponsiveness (AHR). The lungs of animals treated with ROF exhibited less airway inflammation and hyperresponsiveness. To investigate the mechanism underlying this effect, we examined the expression of proinflammatory cytokines suspected to be involved in inflammatory cytokines and proteins. Roflumilast reduced total protein in bronchioalveolar lavage fluid; levels of interleukin (IL)-17A, IL-1β messenger RNA, interferon γ and tumour necrosis factor α; and recovered histone deacetylase-2 (HDAC2) activity. Combination therapy with ROF and DEX further reduced the levels of IL-17, IL-22 and IL-1β mRNA and proinflammatory cytokines. The combination of ROF and DEX reduced lung inflammation and AHR much more than one of them alone. Roflumilast reduces AHR and lung inflammation in the neutrophilic asthma mouse model. Furthermore, additive effects were observed when DEX was added to ROF treatment, possibly because of recovery of HDAC2/β-actin activity. This study demonstrates the anti-inflammatory properties of ROF in a neutrophilic asthma mouse model.

WITHDRAWN: MiR-140 suppresses airway inflammation and inhibits bronchial epithelial cell apoptosis in asthma by targeting GSK3β

Asthma is a common and complex chronic inflammatory disease induced by genetic and environmental factors that affects the airways of the lungs. MicroRNAs (miRNAs) are key regulators of various cellular processes and have been shown to be critically involved in asthma progression. The objective of our study was to clarify the function and molecular mechanism of miR-140 in the progression of asthma. MiR-140 expression was evaluated using RT-qPCR. Pathological changes in the lung tissue were confirmed using HE and PAS staining. The levels of IL-5, TGF-β1, and IL-13 in the serum or bronchioalveolar lavage fluid were detected with an ELISA. Cellular apoptosis was measured using a TUNEL assay. The levels of Bax, Bcl-2, Cleaved caspase-3, and glycogen synthase kinase-3β (GSK-3β) were verified with a western blot. GSK3β expression was also confirmed by immunohistochemistry. The binding ability between miR-140 and GSK3β was confirmed using a luciferase reporter assay, RNA immunoprecipitation (RIP) assay and Pull-down assay. MiR-140 was markedly downregulated in asthmatic mice. Additionally, miR-140 weakened airway inflammation and bronchial epithelial cell apoptosis in asthmatic mice. Further experiments revealed that miR-140 negatively regulated GSK3β expression and could bind to GSK3β in asthma. Finally, rescue assays demonstrated that GSK3β overexpression rescued the effects of miR-140 on asthma progression. MiR-140 targeted GSK3β to suppress airway inflammation and inhibit bronchial epithelial cell apoptosis in asthma.

Surfactant Proteins A/D-CD14 on Alveolar Macrophages Is a Common Pathway Associated With Phagocytosis of Nanomaterials and Cytokine Production.

Alveolar macrophages are responsible for clearance of airborne dust and pathogens. How they recognize and phagocytose a variety of engineered nanomaterials (ENMs) with different properties is an important issue for safety assessment of ENMs. Surfactant-associated proteins, specifically existing in the pulmonary surfactant, are important opsonins for phagocytosis of airborne microorganisms. The purposes of the current study are to understand whether opsonization of ENMs by surfactant-associated proteins promotes phagocytosis of ENMs and cytokine production, and to determine whether a common pathway for phagocytosis of ENMs with different properties exists. For these purposes, four ENMs, MWCNT-7, TiO2, SiO2, and fullerene C60, with different shapes, sizes, chemical compositions, and surface reactivities, were chosen for this study. Short-term pulmonary exposure to MWCNT-7, TiO2, SiO2, and C60 induced inflammation in the rat lung, and most of the administered ENMs were phagocytosed by alveolar macrophages. The ENMs were phagocytosed by isolated primary alveolar macrophages (PAMs) in vitro, and phagocytosis was enhanced by rat bronchioalveolar lavage fluid (BALF), suggesting that proteins in the BALF were associated with phagocytosis. Analysis of proteins bound to the 4 ENMs by LC/MS indicated that surfactant-associated proteins A and D (SP-A, SP-D) were common binding proteins for all the 4 ENMs. Both BALF and SP-A, but not SP-D, enhanced TNF-α production by MWCNT-7 treated PAMs; BALF, SP-A, and SP-D increased IL-1β production in TiO2 and SiO2 treated PAMs; and BALF, SP-A, and SP-D enhanced IL-6 production in C60 treated PAMs. Knockdown of CD14, a receptor for SP-A/D, significantly reduced phagocytosis of ENMs and SP-A-enhanced cytokine production by PAMs. These results indicate that SP-A/D can opsonize all the test ENMs and enhance phagocytosis of the ENMs by alveolar macrophages through CD14, suggesting that SP-A/D-CD14 is a common pathway mediating phagocytosis of ENMs. Cytokine production induced by ENMs, however, is dependent on the type of ENM that is phagocytosed. Our results demonstrate a dual role for surfactant proteins as opsonins for both microbes and for inhaled dusts and fibers, including ENMs, allowing macrophages to recognize and remove the vast majority of these particles, thereby, greatly lessening their toxicity in the lung.

Interleukin-22 mitigates acute respiratory distress syndrome (ARDS).

BackgroundThe goal of this study was to determine if IL-22:Fc would Acute Respiratory Distress Syndrome (ARDS).Summary background dataNo therapies exist for ARDS and treatment is purely supportive. Interleukin-22 (IL-22) plays an integral component in recovery of the lung from infection. IL-22:Fc is a recombinant protein with a human FC immunoglobulin that increases the half-life of IL-22.Study designARDS was induced in C57BL/6 mice with intra-tracheal lipopolysaccharide (LPS) at a dose of 33.3 or 100 ug. In the low-dose LPS group (LDG), IL-22:FC was administered via tail vein injection at 30 minutes (n = 9) and compared to sham (n = 9). In the high-dose LPS group (HDG), IL-22:FC was administered (n = 11) then compared to sham (n = 8). Euthanasia occurred after bronchioalveolar lavage (BAL) on post-injury day 4.ResultsIn the LDG, IL-22:FC resulted in decreased protein leak (0.15 vs. 0.25 ug/uL, p = 0.02). BAL protein in animals receiving IL-22:Fc in the HDG was not different. For the HDG, animals receiving IL-22:Fc had lower BAL cell counts (539,636 vs 3,147,556 cells/uL, p = 0.02). For the HDG, IL-6 (110.6 vs. 527.1 pg/mL, p = 0.04), TNF-α (5.87 vs. 25.41 pg/mL, p = 0.04), and G-CSF (95.14 vs. 659.6, p = 0.01) levels were lower in the BAL fluid of IL-22:Fc treated animals compared to sham.ConclusionsIL-22:Fc decreases lung inflammation and lung capillary leak in ARDS. IL-22:Fc may be a novel therapy for ARDS.

Anti‐inflammatory cholinergic system modulates LPS‐induced acute lung injury

Lung cholinergic system suing acetylcholine (ACh) as a neurotransmitter regulates lung inflammation and is believed to play an anti-inflammatory role via activation of nicotinic (nAChR) and/or muscarinic (mAChR) acetylcholine receptors expressed in lung tissue. Therefore, studies that evaluate the effects of lung cholinergic deficiency are relevant to understand the multiple actions of ACh in acute lung injury (ALI). Aim To evaluate whether VAChT deficiency and treatment with agonist α-7 nAChR affects lung alterations observed in an experimental model of ALI. Methods Wild-Type (WT) mice and mice with decreased expression of VAChT KDHOM, which is correlated with 70% less of ACh release, received PNU-282987 (specific α7nAChR agonist,10 mg/kg) 6 hours after LPS (1mg/kg) intratracheal instillation. We evaluated lung inflammation focusing on inflammation in bronchioalveolar lavage fluid (BALF). We also compared the expression levels of α-7 and α-4 nAChRs in lung tissue using radioligand binding assays. Results LPS treatment induced higher increase in inflammatory cells in BALF in VAChT KDHOM compared to WT mice. The activation α-7 nAChR by treatment with PNU-282987 reduced the total cells, macrophages, and neutrophils recovered in BALF (p<0.001 for all comparisons) in both VAChT-KDHOM and WT that received LPS. The LPS induced upregulate α-7 nAChR levels in WT mice but not in the VAChT KDHOM mice. However, treatment with PNU-282987 induced increase in α-7 nAChR levels in LPS-treated VAChT-KDHOM mice. Unlike α-7 nAChR, α-4 nAChR expression was not changed by VAChT reduction, LPS-induce, and PNU-282987 treatment. Conclusion Our preliminary results suggest that α-7 nAChR upregulation contributes to the anti-inflammatory effect of lung cholinergic system. Unlike WT mice, VAChT-KDHOM mice did not upregulate α-7 nAChR in response to inflammatory insult (LPS treatment) resulting in higher inflammation in VAChT-KDHOM mice than WT mice. Furthermore, treatment of VAChT-KDHOM mice with PNU-282987 resulted in increase in α-7 nAChR expression in lung tissue and reduction of LPS-induced lung inflammation. Experiments to determine mAChRs expression in WT vs. VAChT-KDHOM mice are ongoing.

Single-Dose Toxicity of Individual and Combined Sterigmatocystin and 5-Methoxysterigmatocistin in Rat Lungs.

Sterigmatocystin (STC) and 5-methoxysterigmatocystin (5-M-STC) are mycotoxins produced by common damp indoor Aspergilli series Versicolores. Since both STC and 5-M-STC were found in the dust of indoor occupational and living areas, their occupants may be exposed to these mycotoxins, primarily by inhalation. Thus, STC and 5-M-STC were intratracheally instilled in male Wistar rats using doses (0.3 mg STC/kg of lung weight (l.w.); 3.6 mg 5-M-STC/kg l.w.; toxin combination 0.3 + 3.6 mg/kg l.w.) that corresponded to concentrations detected in the dust of damp indoor areas in order to explore cytotoxicity, vascular permeability, immunomodulation and genotoxicity. Single mycotoxins and their combinations insignificantly altered lactate-dehydrogenase activity, albumin, interleukin-6, tumor necrosis factor-α and chemokine macrophage inflammatory protein-1α concentrations, as measured by ELISA in bronchioalveolar lavage fluid upon 24 h of treatment. In an alkaline comet assay, both mycotoxins provoked a similar intensity of DNA damage in rat lungs, while in a neutral comet assay, only 5-M-STC evoked significant DNA damage. Hence, naturally occurring concentrations of individual STC may induce DNA damage in rat lungs, in which single DNA strand breaks prevail, while 5-M-STC was more responsible for double-strand breaks. In both versions of the comet assay treatment with STC + 5-M-STC, less DNA damage intensity occurred compared to single mycotoxin treatment, suggesting an antagonistic genotoxic action.

Mucosal Vaccination with a Novel Live Attenuated Brucella melitensis Mutant Protects via IFN-γ-producing Memory CD8+ T Cells in Concert with B Cells

Abstract A B. melitensis mutant vaccine expressing mCherry (znBM-mC), when applied mucosally, conferred nearly complete protection against pulmonary challenge with wild-type (wt) BM 16M than did BM Rev-1 vaccine. To identify cellular subsets and mechanisms involved in inducing and maintaining protection post-BMDM vaccination, we hypothesize that both arms of the adaptive immune system are required for optimal protection. Mucosal vaccination with znBM-mC induced both effector memory and resident memory CD8+ T cells in the lungs, which were the primary source of IFN-γ. In the absence of IFN-γ, IL-17 significantly increased, but was insufficient for protection. In the absence of B cells, the total number of lung CD8+ T cells and proinflammatory cytokine production were significantly reduced resulting in diminished systemic protection. Reconstitution with naïve or immune B cells restored some protection in znBM-mC-vaccinated B cell-deficient mice. B cell involvement begins as early as 5 days post-nasal vaccination. Total CD19+ B cells significantly increased in BALB/c head and neck lymph nodes (LNs), lower respiratory LNs, and bronchio-alveolar lavage fluid. mCherry+ BALB/c B cells were elevated in the lungs and spleen correlating to a significant increase in CD8+ T cell expansion in the spleen compared to B cell-deficient mice. In-vitro uptake of znBM-mC by B cells resulted in their activation evidenced by increased CD80, CD86, CD11b, and CD24 expression. Moreover, purified immune CD8+ T cells co-cultured with znBM-mC-infected B cells showed enhanced T cell proliferation. Although B cells become infected with Brucella, these are important for optimal T cell immunity. Work is supported by NIH AI123244 &amp; AI125516.

Abstract A38: Oncogenes drive production of immunosuppressive cytokines to facilitate lung cancer progression

Abstract Lung cancer development is driven by the expression of mutant oncogenes, with EGFR and KRAS being the most frequent mutations in lung adenocarcinoma. However, these mutations alone are not sufficient for tumorigenesis, and additional factors influence tumor development and progression, including the balance of antitumor immune effector cells and protumorigenic immune suppressor cells within the tumor environment. We hypothesized that oncogene signaling regulates the production of cytokines by tumor cells in order to modulate the immune microenviroment and promote lung tumor development. We used CIBERSORT to quantify 22 immune cell types in over 300 human lung adenocarcinomas (LUAD) and 100 matched normal lung tissues. Cells associated with inflammatory or antitumor response, macrophages (M1, M0), T follicular helper cells, and plasma cells, were enriched in LUAD compared to normal lung tissue. Additionally, immunosuppressive regulatory T cells (Tregs) were significantly enriched in LUAD tumors, even at the early stages. To identify cytokines that could be induced by oncogenic signaling early in lung tumorigenesis, we used normal cells expressing doxycycline-inducible mutant KRASG12V mutant EGFRL858R or wild-type EGFR and analyzed cytokine production with a multiplex assay (LUMINEX). Induction of oncogenic signaling in normal cells rapidly increased production of cytokines CCL5 and CCL2. These are capable of recruiting a variety of cells types, including Tregs. In KRAS mutant lung cancer cells, disruption of oncogene signaling with a MEK inhibitor (trametinib) decreased CCL5 production. We used transgenic mice that spontaneously develop lung tumors in response to tetracycline-inducible expression of mutant EGFRDelEx19 or mutant KRASG12V in type II alveolar cells to investigate immune cell populations that may change in response to oncogene-driven lung tumorigenesis. We found that Tregs were increased in the lungs of tumor-bearing mice. These Tregs express the CCL5 receptor, CCR5. Several cytokines were elevated in bronchioalveolar lavage fluid or in lung lysates of tumor-bearing mice, including IL-12(p40), CXCL1, CCL2, CCL3 and CCL5. Murine Lewis lung carcinoma (LLC) cells harbor a KRAS mutation and express high levels of CCL5. We are currently investigating the effects of disrupting oncogene signaling or CCL5 expression in LLC cells on cytokine production and immune cell recruitment in vivo using syngeneic implantation of the cells into mice. Our data suggest that oncogenic signaling regulates expression of cytokines in lung tumor cells. Targeted inhibition of cytokines directly or indirectly through oncogenic signaling may represent therapeutic strategies to block the recruitment of immune-suppressive cells to the tumor microenvironment, thereby enhancing the antitumor immune response. Citation Format: Elizabeth Franks, Etienne Melese, Bryant Harbourne, Liz Halvorsen, Rachel Cederberg, Jenna Collier, Natalie Firmino, Jennifer Luu, Arun Unni, Min Hee Oh, Vivian Lam, Gerry Krystal, Ninan Abraham, Kevin Bennewith, William Lockwood. Oncogenes drive production of immunosuppressive cytokines to facilitate lung cancer progression [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2018 Nov 27-30; Miami Beach, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(4 Suppl):Abstract nr A38.

IL-9 blockade attenuates inflammation in a murine model of methicillin-resistant Staphylococcus aureus pneumonia.

Methicillin-resistant Staphylococcus aureus (MRSA) is an important etiology of pneumonia. Interleukin (IL)-9 is a T helper 9 (Th9) cytokine and participates in the pathogenesis of infectious diseases. Here, we investigated the role of IL-9 by using an MRSA pneumonia animal model. The BALB/c mice underwent nasal inhalation with an ST239 MRSA strain to establish the mouse model of MRSA pneumonia, and a subset of mice were intravenously injected with IL-9 neutralizing antibody or immunoglobulin (Ig) G. At 3 and 8days postinfection, the peripheral blood, bronchioalveolar lavage fluid (BALF), and lung tissues were collected. The frequencies of Th9 cells and the levels of cytokines in peripheral blood, BALF, and lung tissues were determined by flow cytometry and enzyme-linked immunosorbent assay (ELISA), respectively. The colony counts of MRSA in BALF and lung tissue were detected. The lung pathological changes were examined using hematoxylin and eosin staining. Data from flow cytometry, qRT-PCR, and ELISA showed that MRSA-infected mice exhibited higher frequency of Th9 cells and higher IL-9 mRNA and protein levels in the peripheral blood, BALF, and lung tissues of mice. In contrast, the neutralization of IL-9 abrogated MRSA inoculation-induced Th9 cell generation and IL-9 production in BALF and lung tissues. Furthermore, bacterial counting and histological examination showed that the numbers of bacteria in BALF and lungs and the lung pathological scores induced by MRSA inoculation were attenuated by the neutralization of IL-9. Moreover, cell counting and ELISA results demonstrated that IL-9 neutralization diminished the MRSA inoculation-induced count of neutrophils and macrophages and levels of pro-inflammatory cytokines in BALF. Collectively, IL-9 neutralization attenuated inflammation of MRSA pneumonia by regulating Th9/IL-9 expression.

Xenogeneic and Allogeneic Mesenchymal Stem Cells Effectively Protect the Lung Against Ischemia-reperfusion Injury Through Downregulating the Inflammatory, Oxidative Stress, and Autophagic Signaling Pathways in Rat

This study tested the hypothesis that both allogenic adipose-derived mesenchymal stem cells (ADMSCs) and human inducible pluripotent stem cell-derived MSCs (iPS-MSCs) offered a comparable effect for protecting the lung against ischemia-reperfusion (IR) injury in rodent through downregulating the inflammatory, oxidative stress, and autophagic signaling pathways. Adult male Sprague–Dawley rats (n = 32) were categorized into group 1 (sham-operated control), group 2 (IRI), group 3 [IRI + ADMSCs (1.0 × 106 cells)/tail-vein administration at 0.5/18/36 h after IR], and group 4 [IRI + iPS-MSCs (1.0 × 106 cells)/tail-vein administration at 0.5/18/36 h after IR], and lungs were harvested at 72 h after IR procedure. In vitro study demonstrated that protein expressions of three signaling pathways in inflammation (TLR4/MyD88/TAK1/IKK/I-κB/NF-κB/Cox-2/TNF-α/IL-1ß), mitochondrial damage/cell apoptosis (cytochrome C/cyclophilin D/DRP1/ASK1/APAF-1/mitochondrial-Bax/caspase3/8/9), and autophagy/cell death (ULK1/beclin-1/Atg5,7,12, ratio of LCB3-II/LC3B-I, p-AKT/m-TOR) were significantly higher in lung epithelial cells + 6h hypoxia as compared with the control, and those were significantly reversed by iPS-MSC treatment (all P < 0.001). Flow cytometric analysis revealed that percentages of the inflammatory cells in bronchioalveolar lavage fluid and circulation, and immune cells in circulation/spleen as well as circulatory early and late apoptotic cells were highest in group 2, lowest in group 1, and significantly higher in group 3 than in group 4 (all P < 0.0001). Microscopy showed the lung injury score and numbers of inflammatory cells and Western blot analysis showed the signaling pathways of inflammation, mitochondrial damage/cell apoptosis, autophagy, and oxidative stress exhibited an identical pattern of flow cytometric results among the four groups (all P < 0.0001). Both xenogeneic and allogenic MSCs protected the lung against IRI via suppressing the inflammatory, oxidative stress, and autophagic signaling.