Lung Inflammation In Murine Model Research Articles

Herbo-metallic ethnomedicine ‘Malla Sindoor’ ameliorates lung inflammation in murine model of allergic asthma by modulating cytokines status and oxidative stress

Ethnopharmacological relevanceAsthma is the leading inflammatory disease of the airways with inadequate therapeutic options. ‘Malla Sindoor’ (MS) is a metal-based ethnomedicinal formulation that has been prescribed in the ancient traditional medicinal system for treating chronic inflammations. Aim of the studyHere, we validated the anti-inflammatory and anti-asthmatic properties of traditional metallic medicine MS in asthmatic mice model and in LPS stimulated human monocytic THP-1 cells, by examining the relevant cellular, biochemical and molecular intermediates. Materials and methodsScanning Electron Microscope (SEM), Electron Dispersive X-ray (EDX), and X-Ray Diffraction (XRD) were performed to characterize MS particles. Allergic asthma was induced in Balb/c mice through intraperitoneal ovalbumin (OVA) injection. Experimental groups include, normal control, disease control, Dexamethasone (2 mg/kg) and three MS treated groups: 4.3 mg/kg, 13 mg/kg, and 39 mg/kg. Quantitative PCR, inflammatory cytokines and anti-oxidant enzymes, and histological analysis were performed, in the treated mice and LPS stimulated human monocytic THP-1 cells for determining the MS efficacy. ResultsSEM image analysis showed the MS to be heterogenous in shape with a particle size distribution between 100 nm–1 μm. Elemental composition showed the presence of mercury (Hg), arsenic (As), and sulphur (S) along with other elements in the forms of mercury sulfide, arsenic trioxide, and their alloy crystals. OVA-challenge of the Balb/c mice resulted in the development of overt pathological features for allergic asthma including smooth muscle thickening and collagen deposition. Mice receiving MS-exhibited alleviation of allergic asthma features. BAL fluid analysis showed a decrease in the total cell count and decreases in neutrophils, monocytes, lymphocytes, and eosinophils. Further, the stimulated levels of interleukin (IL)-1β, −6, and TNF-α cytokines and antioxidant levels were also reduced upon MS-treatment. At the molecular level, MS-treatment reduced stimulated mRNA expression levels for IL-4, -5, -10, -13, -33, and IFN-γ cytokines. Histological analysis following MS-treatment of OVA-stimulated mice lungs showed a reduction in mucus accumulation in airways, decreases in peribronchial collagen deposition, bronchial smooth muscle thickening, and attenuation of inflammatory cell infiltration. In addition, under in-vitro conditions, MS-treatment attenuated the LPS induced secretion of IL-1β, −6, and TNF-α from THP-1 cells. ConclusionCollectively, the results suggest that MS acts as an effective anti-asthmatic and anti-inflammatory agent, by regulating various cellular, biochemical and molecular intermediates.

Dietary New Zealand propolis supplementation reduced proinflammatory cytokines in an acute mouse model of air pollution exposure, without impacting on immune cell infiltration or lung function

• Propolis reduced urban dust-induced lung TNFα, IL-4, and IL-6 production in mice. • Propolis did not alter urban dust-induced immune cell infiltration into mice lungs. • Propolis did not alter urban dust-induced airways constriction in mice. • This suggests that Propolis only partially reduces inflammatory responses in an urban dust mouse model. Air pollution is estimated to cause 7 million annual deaths globally. Our aim was to determine if dietary propolis consumption could prevent the immune and functional damage in a mouse model of acute urban dust exposure. Female C57BL/6J mice were challenged three times with intranasal urban dust over seven days which significantly increased proinflammatory cytokines and immune cells in the lung 24 h post final challenge. Dietary New Zealand propolis (2%) with gamma cyclodextrin supplementation reduced urban dust-induced lung TNFα, IL-4, and IL-6 cytokine production; but did not alter immune cell infiltration into the lung, or lung function outcomes. This suggests that daily consumption of 8% propolis with gamma cyclodextrin supplemented food was sufficient to reduce urban dust pollution-induced proinflammatory cytokine production but was not sufficient to prevent immune cell recruitment into the lung or lung function decline in a murine model of lung inflammation.

Pharmacological profiling of JME-173, a novel mexiletine derivative combining dual anti-inflammatory/anti-spasmodic functions and limited action in Na+ channels

Existing evidence suggests that the local anaesthetic mexiletine can be beneficial for patients with asthma. However, caution is required since anaesthesia of the airways inhibits protective bronchodilator neuronal reflexes, limiting applications in conditions of hyperirritable airways. Here, we describe the synthesis of a new series of mexiletine analogues, which were screened for reduced activity in Na+ channels and improved smooth muscle relaxant effects, that were evaluated using the patch-clamp technique and an isolated tracheal organ bath, respectively. JME-173 (1-(4-bromo-3,5-dimethylphenoxy)propan-2-amine) was the most effective among the four mexiletine analogues investigated. JME-173 was then studied in vivo using a murine model of lung inflammation induced by cigarette smoke (CS) and in vitro using neutrophil chemotaxis and mast cell degranulation assays. Finally, the JME-173 pharmacokinetic profile was assessed using HPLC-MS/MS bioanalytical method. JME-173 directly inhibited IL-8 (CXCL8)- and FMLP-induced human neutrophil chemotaxis and allergen-induced mast cell degranulation. After oral administration 1 h before CS exposure, JME-173 (50 mg/kg) strongly reduced the increased number of macrophages and neutrophils recovered in the bronchoalveolar effluent without altering lymphocyte counts. Pharmacokinetic experiments of JME-173 (10 mg/kg, orally) showed values of maximum concentration (Cmax), maximum time (Tmax), area under the blood concentration-time curve (AUC0-t) and area under the blood concentration-time curve from 0–Inf (AUC0-inf) of 163.3 ± 38.3 ng/mL, 1.2 ± 0.3 h, 729.4 ± 118.3 ng*h/ml and 868.9 ± 117.1 ng*h/ml (means ± S.E.M.), respectively. Collectively, these findings suggest that JME-173 has the potential to be an effective oral treatment for diseases associated with bronchoconstriction and inflammation.

Antisense oligonucleotide targeting of thrombopoietin represents a novel platelet depletion method to assess the immunomodulatory role of platelets

BackgroundPlatelets are effector cells of the innate and adaptive immune system; however, understanding their role during inflammation‐driven pathologies can be challenging due to several drawbacks associated with current platelet depletion methods. The generation of antisense oligonucleotides (ASOs) directed to thrombopoietin (Tpo) mRNA represents a novel method to reduce circulating platelet count. ObjectiveTo understand if Tpo‐targeted ASO treatment represents a viable strategy to specifically reduce platelet count in mice. MethodsFemale and male mice were treated with TPO‐targeted ASOs and platelet count and function was assessed, in addition to circulating blood cell counts and hematopoietic stem and progenitor cells. The utility of the platelet‐depletion strategy was assessed in a murine model of lower airway dysbiosis. Results and ConclusionsHerein, we describe how in mice, ASO‐mediated silencing of hepatic TPO expression reduces platelet, megakaryocyte, and megakaryocyte progenitor count, without altering platelet activity. TPO ASO‐mediated platelet depletion can be achieved acutely and sustained chronically in the absence of adverse bleeding. TPO ASO‐mediated platelet depletion allows for the reintroduction of new platelets, an advantage over commonly used antibody‐mediated depletion strategies. Using a murine model of lung inflammation, we demonstrate that platelet depletion, induced by either TPO ASO or anti‐CD42b treatment, reduces the accumulation of inflammatory immune cells, including monocytes and macrophages, in the lung. Altogether, we characterize a new platelet depletion method that can be sustained chronically and allows for the reintroduction of new platelets highlighting the utility of the TPO ASO method to understand the role of platelets during chronic immune‐driven pathologies.

PEGylation of a glycosaminoglycan-binding, dominant-negative CXCL8 mutant retains bioactivity in vitro and in vivo

We have recently shown that a dominant-negative mutant of CXCL8, dnCXCL8, with increased glycosaminoglycan (GAG) binding affinity and inactivated GPCR signaling function is able to efficiently prevent neutrophil infiltration into murine lungs (Adage et al., 2015). Here we present evidence that chemical PEGylation of dnCXCL8 with 20 kDa and 40 kDa PEG does not significantly interfere with GAG binding affinity, nor does it influence the mutant’s disabled chemotaxis function, while it strongly improved bioavailability and serum half-life of the chemokine mutant. In a murine model of lung inflammation, only the 40 kDa PEGylated dnCXCL8 showed a significant reduction of neutrophils in bronchoalveolar lavage (BAL) fluid. In combination with an almost three-fold increase (compared to non-PEGylated dnCXCL8) in plasma half-life after intravenous administration, our results prove that PEGylation of chemokine-derived biologics is an amenable way for the treatment of chronic inflammatory conditions.

How Adhesion Molecule Patterns Change While Neutrophils Traffic through the Lung during Inflammation.

In acute pulmonary inflammation, polymorphonuclear cells (PMNs) pass a transendothelial barrier from the circulation into the lung interstitium followed by a transepithelial migration into the alveolar space. These migration steps are regulated differentially by a concept of adhesion molecules and remain—despite decades of research—incompletely understood. Current knowledge of changes in the expression pattern of adhesion molecules mainly derives from in vitro studies or from studies in extrapulmonary organ systems, where regulation of adhesion molecules differs significantly. In a murine model of lung inflammation, we determined the expression pattern of nine relevant neutrophilic adhesion molecules on their way through the different compartments of the lung. We used a flow cytometry-based technique that allowed describing spatial distribution of the adhesion molecules expressed on PMNs during their migration through the lung in detail. For example, the highest expression of CD29 was found in the intravascular compartment, highlighting its impact on the initial adhesion to the endothelium. CD47 showed its peak of expression on the later phase of transendothelial migration, whereas CD11b and CD54 expression peaked interstitial. A pivotal role for transepithelial migration was found for the adhesion molecule CD172a. Thereby, expression may correlate with functional impact for specific migration steps. In vitro studies further confirmed our in vivo findings. In conclusion, we are the first to determine the changes in expression patterns of relevant adhesion molecules on their migration through the different compartments of the lung. These findings may help to further understand the regulation of neutrophil trafficking in the lung.

Mutations of Cystic Fibrosis Transmembrane Conductance Regulator Gene Cause a Monocyte-Selective Adhesion Deficiency.

Cystic fibrosis (CF) is a common genetic disease caused by mutations of the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Persistent lung inflammation, characterized by increasing polymorphonuclear leukocyte recruitment, is a major cause of the decline in respiratory function in patients with CF and is a leading cause of morbidity and mortality. CFTR is expressed in various cell types, including leukocytes, but its involvement in the regulation of leukocyte recruitment is unknown. We evaluated whether CF leukocytes might present with alterations in cell adhesion and migration, a key process governing innate and acquired immune responses. We used ex vivo adhesion and chemotaxis assays, flow cytometry, immunofluorescence, and GTPase activity assays in this study. We found that chemoattractant-induced activation of β1 and β2 integrins and of chemotaxis is defective in mononuclear cells isolated from patients with CF. In contrast, polymorphonuclear leukocyte adhesion and chemotaxis were normal. The functionality of β1 and β2 integrins was restored by treatment of CF monocytes with the CFTR-correcting drugs VRT325 and VX809. Moreover, treatment of healthy monocytes with the CFTR inhibitor CFTR(inh)-172 blocked integrin activation by chemoattractants. In a murine model of lung inflammation, we found that integrin-independent migration of CF monocytes into the lung parenchyma was normal, whereas, in contrast, integrin-dependent transmigration into the alveolar space was impaired. Finally, signal transduction analysis showed that, in CF monocytes, chemoattractant-triggered activation of RhoA and CDC42 Rho small GTPases (controlling integrin activation and chemotaxis, respectively) was strongly deficient. Altogether, these data highlight the critical regulatory role of CFTR in integrin activation by chemoattractants in monocytes and identify CF as a new, cell type-selective leukocyte adhesion deficiency disease, providing new insights into CF pathogenesis.

Modulation of IL-17A and TL1A largely abrogates house dust mite-induced lung inflammation in murine model of allergic airway disease

Recent studies suggest a role for Th17 responses in the increased airway neutrophilia associated with severe asthma. House dust mite (HDM) is a natural allergen to which asthmatics are often sensitized. Mice repeatedly challenged with HDM extract developed robust airway neutrophilia rapidly evolving into asthma-like disease with increased numbers of eosinophils and lymphocytes in bronchoalveolar lavages (BAL) as well as inflammatory infiltrates, vascular/muscular hypertrophy, interstitial fibrosis, epithelial hyperplasia and mucus accumulation in lung tissues. RNA and protein screening revealed a robust Th17 component post-HDM exposure. We thus evaluated whether IL-17A deficiency could modulate HDM-induced allergic airway disease. Airway neutrophilia was indeed abrogated in IL-17A deficient mice weekly challenged with HDM (acute model), however total BAL cellularity and lung mechanics remained comparable to those of HDM-challenged WT mice. In contrast, IL-17A deficient mice daily exposed to HDM (chronic model) had decreased BAL cellularity associated with reduced numbers of BAL macrophages, neutrophils, eosinophils and lymphocytes. Interestingly antibody neutralization of TL1A, a member of the TNF superfamily known to promote Th2 and Th17 responses, reduced BAL cellularity to baseline levels in HDM-challenged WT mice. Our results thus indicate that targeting Th17 responses can alleviate HDM-induced airway neutrophilia, and can also broadly modulate allergic airway disease.

Immunological characterisation of an acute murine model of lung inflammation and airway hyperreactivity

Asthma is associated with chronic airway inflammation and airway hyperreactivity (AHR). Approximately 5-10% of the asthmatic patient population suffers from severe disease which remains uncontrolled by current therapies. An acute murine model that replicates aspects of severe asthma was established. Airway inflammation and AHR were elicited by s.c. sensitisation to house dust mite extract (HDM) in complete Freund’s adjuvant (CFA) and a subsequent HDM challenge into the airways (i.n.) 14 days later. The ensuing inflammation comprised of eosinophilia, a marked neutrophilia and a mixed T cell response with significant infiltration of Th1, Th2 and Th17 cells into airways. To investigate the role of these T-helper subsets in this model, the effects of neutralising the key T-helper cell cytokines IFNγ (Th1), IL-4 (Th2) and IL-17 (Th17) were evaluated. Neutralising antibodies to IFNγ, IL-4 and IL-17 were administered prophylactically (s.c), from one day prior to HDM immunisation. AHR to methacholine was assessed by Penh 48 hours post HDM challenge followed by collection of broncho-alveolar lavage (BAL) and serum for analysis of cellular inflammation, cytokines and HDM specific antibodies. IFNγ neutralisation profoundly inhibited AHR yet enhanced BAL eosinophilia, neutrophilia, IL-17 levels and HDM specific serum IgE. Conversely, anti-IL-4 treatment inhibited eosinophil accumulation, IL-13 production and HDM specific serum IgE and IgG1, without affecting AHR. Anti-IL-17 treatment reduced BAL neutrophilia and KC levels, however no significant modulation of AHR, eosinophilia or HDM specific serum IgE and IgG1 was observed. In summary, the T cell cytokines IFNγ, IL-4, and IL-17 each play distinct roles in the development of airway inflammation and AHR in this acute murine model. Furthermore, these data indicate there is dissociation between cellular inflammation and hyperreactivity of the airways in this model. In conclusion, this acute HDM driven model may be representative of the mixed inflammatory response (Th1, Th2 & Th17) reported to be present in the airways of severe asthmatics.

Feasibility and Dosimetry Studies for 18F-NOS as a Potential PET Radiopharmaceutical for Inducible Nitric Oxide Synthase in Humans

Nitric oxide (NO), the end product of the inducible form of NO synthase (iNOS), is an important mediator of a variety of inflammatory diseases. Therefore, a radiolabeled iNOS radiopharmaceutical for assessing iNOS protein concentration as a marker for its activity would be of value to the study and treatment of NO-related diseases. We recently synthesized an (18)F-radiolabeled analog of the reversible NOS inhibitor, 2-amino-4-methylpyridine ((18)F-NOS), and confirmed its utility in a murine model of lung inflammation. To determine its potential for use in humans, we measured (18)F-NOS myocardial activity in patients after orthotopic heart transplantation (OHT) and correlated it with pathologic allograft rejection, tissue iNOS levels, and calculated human radiation dosimetry. Two groups were studied-a kinetic analysis group and a dosimetry group. In the kinetic analysis group, 10 OHT patients underwent dynamic myocardial (18)F-NOS PET/CT, followed by endomyocardial biopsy. Myocardial (18)F-NOS PET was assessed using volume of distribution; standardized uptake values at 10 min; area under the myocardial moment curve (AUMC); and mean resident time at 5, 10, and 30 min after tracer injection. Tissue iNOS levels were measured by immunohistochemistry. In the dosimetry group, the biodistribution and radiation dosimetry were calculated using whole-body PET/CT in 4 healthy volunteers and 12 OHT patients. The combined time-activity curves were used for residence time calculation, and organ doses were calculated with OLINDA. Both AUMC at 10 min (P < 0.05) and tissue iNOS (P < 0.0001) were higher in patients exhibiting rejection than in those without rejection. Moreover, the (18)F-NOS AUMC at 10 min correlated positively with tissue iNOS at 10 min (R(2) = 0.42, P < 0.05). (18)F-NOS activity was cleared by the hepatobiliary system. The critical organ was the bladder wall, with a dose of 95.3 μGy/MBq, and an effective dose of 15.9 μSv/MBq was calculated. Myocardial (18)F-NOS activity is increased in organ rejection (a condition associated with increased iNOS levels) and correlates with tissue iNOS measurements with acceptable radiation exposure. Although further modifications to improve the performance of (18)F-NOS are needed, these data show the feasibility of PET of iNOS in the heart and other tissues.

The discovery and development of selective 3-fluoro-4-aryloxyallylamine inhibitors of the amine oxidase activity of semicarbazide-sensitive amine oxidase/vascular adhesion protein-1 (SSAO/VAP-1)

A new class of 3-fluoroallyl amine-based SSAO/VAP-1 inhibitors is reported. These compounds have excellent selectivity over diamine oxidase, MAO-A and MAO-B. Synthesis and SAR studies leading to compound 28 (PXS-4159A) are reported. The pharmacokinetic profile of 28 in the rat, together with activity in a murine model of lung inflammation are also disclosed.

Pulmonary Administration of a Water-Soluble Curcumin Complex Reduces Severity of Acute Lung Injury

Local or systemic inflammation can result in acute lung injury (ALI), and is associated with capillary leakage, reduced lung compliance, and hypoxemia. Curcumin, a plant-derived polyphenolic compound, exhibits potent anti-inflammatory properties, but its poor solubility and limited oral bioavailability reduce its therapeutic potential. A novel curcumin formulation (CDC) was developed by complexing the compound with hydroxypropyl-γ-cyclodextrin (CD). This results in greatly enhanced water solubility and stability that facilitate direct pulmonary delivery. In vitro studies demonstrated that CDC increased curcumin's association with and transport across Calu-3 human airway epithelial cell monolayers, compared with uncomplexed curcumin solubilized using DMSO or ethanol. Importantly, Calu-3 cell monolayer integrity was preserved after CDC exposure, whereas it was disrupted by equivalent uncomplexed curcumin solutions. We then tested whether direct delivery of CDC to the lung would reduce severity of ALI in a murine model. Fluorescence microscopic examination revealed an association of curcumin with cells throughout the lung. The administration of CDC after LPS attenuated multiple markers of inflammation and injury, including pulmonary edema and neutrophils in bronchoalveolar lavage fluid and lung tissue. CDC also reduced oxidant stress in the lungs and activation of the proinflammatory transcription factor NF-κB. These results demonstrate the efficacy of CDC in a murine model of lung inflammation and injury, and support the feasibility of developing a lung-targeted, curcumin-based therapy for the treatment of patients with ALI.

Lidocaine‐derivative JMF2‐1 prevents ovalbumin‐induced airway inflammation by regulating the function and survival of T cells

Inhalation of the local anaesthetic lidocaine has been suggested to be beneficial for asthmatics, but airway anaesthesia is unpleasant and may exacerbate bronchoconstriction. Our previous study showed that inhalation of the lidocaine analogue JMF2-1 can elicit the anti-inflammatory properties of lidocaine without anaesthesia. This prompted further research on the mechanism of action and putative therapeutic application of JMF2-1. We tested the hypothesis that JMF2-1 would prevent allergen-induced lung inflammation and airway hyperresponsiveness (AHR) by modulating T cell function in vivo and in vitro. Methods Local and systemic changes in leucocyte levels, cytokine production and lung mechanics were examined in a murine model of lung inflammation. JMF2-1 (0.05-2%) or saline was aerosolized twice a day during the ovalbumin (OVA)-provocation period (19-21 days post-sensitization). Analyses were performed 24 h after the final challenge. Primary cultured lymph node cells were used to assess the effects of JMF2-1 (100-600 μm) at the cellular level. OVA challenge resulted in lung recruitment of CD4(+) T cells and eosinophils, increased generation of inflammatory cytokines and AHR to inhaled methacholine within 24 h. These changes were prevented by JMF2-1 nebulization, and occurred in parallel with an increase in the number of apoptotic cells in the lung. JMF2-1 treatment did not alter levels of CD4(+) or CD8(+) T cells in the thymus or lymph nodes of naïve mice, although it inhibited OVA-induced IL-13 production and the lymphocyte proliferative response in vitro. It also induced apoptosis of OVA-activated lymphocytes in a mechanism sensitive to z-VAD, indicating that JMF2-1 mediates caspase-dependent apoptosis. Inhalation of JMF2-1 prevents the cardinal features of asthma by reducing T(H) 2 cytokine generation and lung eosinophilic inflammatory infiltrates via local inhibition of T cell function and survival. JMF2-1 may represent a novel therapeutic alternative for asthma control with distinct advantages over local anaesthetics.

Adenosine receptor A3is a critical mediator in LPS-induced pulmonary inflammation

Adenosine receptor A(3) (A(3)) regulates directed movement of polymorphonuclear cells (PMNs) to sites of inflammation and has been implicated as a relevant mediator in models of inflammatory diseases. Here, we sought to characterize the role of A(3) in a murine model of lung inflammation. Initial studies revealed that pulmonary A(3) transcript levels were elevated following LPS exposure in vivo. In addition, inhalation of LPS increased the accumulation of PMNs in wild-type and A(3)(-/-) mice in all lung compartments. Pretreatment with the specific A(3)-agonist Cl-IB-MECA significantly decreased migration of PMNs into lung interstitium and alveolar air space of wild-type mice but not of A(3)(-/-) mice. Lower PMN counts were associated with reduced levels of TNF-α and IL-6 in the alveolar space of wild-type mice that received Cl-IB-MECA. In addition, Cl-IB-MECA attenuated LPS-induced microvascular permeability in wild-type mice as assessed by the extravasation of Evans blue. In pulmonary microvascular endothelial cells, Cl-IB-MECA reduced LPS-induced cytoskeletal remodeling and cell retraction, consistent with a specific role of A(3) for maintaining endothelial integrity. Migratory activity of human PMNs across an endothelial or epithelial monolayer was reduced when A(3) was activated on PMNs. Studies in chimeric mice, however, revealed that Cl-IB-MECA required A(3) on both hematopoietic and nonhematopoietic cells to reduce transmigration in vivo. Together, our results shed new light on the role of A(3) in LPS-induced PMN trafficking in the lung and suggest pharmacological modulation of A(3)-dependent pathways as a promising approach in lung inflammation.

Synthesis of [125I]iodoDPA-713: A new probe for imaging inflammation

[125I]IodoDPA-713 [125I]1, which targets the translocator protein (TSPO, 18kDa), was synthesized in seven steps from methyl-4-methoxybenzoate as a tool for quantification of inflammation in preclinical models. Preliminary in vitro autoradiography and in vivo small animal imaging were performed using [125I]1 in a neurotoxicant-treated rat and in a murine model of lung inflammation, respectively. The radiochemical yield of [125I]1 was 44±6% with a specific radioactivity of 51.8GBq/μmol (1400mCi/μmol) and >99% radiochemical purity. Preliminary studies showed that [125I]1 demonstrated increased specific binding to TSPO in a neurotoxicant-treated rat and increased radiopharmaceutical uptake in the lungs of an experimental inflammation model of lung inflammation. Compound [125I]1 is a new, convenient probe for preclinical studies of TSPO activity.

Allergen-induced Lung Inflammation in Actively Sensitized Mice Assessed with MR Imaging

To demonstrate the feasibility of using proton magnetic resonance (MR) imaging to noninvasively detect extravascular and luminal fluid in a murine model of allergen-induced airway inflammation. The Basel Veterinary Authority approved this experiment. Actively sensitized female Balb/c mice received ovalbumin or saline and underwent MR imaging (a) once 24 hours after the fourth administration of ovalbumin or saline (n = 25) or (b) several times between and after ovalbumin or saline administrations (n = 22) to determine the volume of fluid signal induced by an allergen. Images were acquired in spontaneously breathing animals, without cardiac or respiratory gating. Signal detected with a gradient-echo sequence was compared with bronchoalveolar lavage (BAL) fluid parameters and with perivascular and peribronchial edema and mucus observed at histologic analysis. Up to 24 hours after the fourth administration of ovalbumin, intense and continuous fluid signals (volume, 40-50 microL) were detected in proximal lung regions. At 72 hours after the fourth administration of ovalbumin, remaining signals (21.1 microL +/- 3.8) had a discontinuous texture. The number of eosinophils in the BAL fluid at 24 and 72 hours and their activation were higher in mice that received ovalbumin than in those that received saline. Histologic analysis revealed edema and secreted mucus in the early phase, whereas only mucus was encountered in the late phase. These findings suggest that the main component of the early response was plasma leakage (edema), while the main component of the late response was secreted mucus. With the technique validated, the basis for pharmacologic studies in this murine model of lung inflammation with use of MR imaging as a noninvasive readout was provided.

Synergistic effect of formoterol and mometasone in a mouse model of allergic lung inflammation

Controversy still exists as to whether or not inhaled beta (2)-adrenoceptor agonists and corticosteroids act synergistically in vivo. In this study, we have used a murine model of lung inflammation to study the synergistic effect of an inhaled beta (2)-adrenoceptor agonist (formoterol) and an inhaled corticosteroid (mometasone). Actively sensitized mice were challenged with aerosolized ovalbumin, once a day, for three consecutive days. Three days after the last of the three challenges, a final allergen challenge was given. Allergen-induced increase in Penh was measured 4 h after the last challenge. A day after the last challenge, increased airway sensitivity to aerosolized methacholine was demonstrated and this was concomitant with an influx of inflammatory cells in the bronchoalveolar lavage fluids. Mometasone (0.1 to 3 mg kg(-1)) given intranasally either an hour before or after the last allergen challenge, dose-dependently inhibited all parameters. When given intranasally either one or three hours after the last allergen challenge, but not an hour before, formoterol (1.5 to 150 microg kg(-1)) also dose-dependently inhibited most of the parameters to different degree. A synergistic effect on the allergen-induced increase in Penh was demonstrated for mometasone and formoterol given in combination, an hour after the challenge, at the following doses: mometasone/formoterol (in microg kg(-1)) 1/10, 1/100, 5/10, and 5/100. Our results support the hypothesis that when given as a fixed combination, inhaled corticosteroid and beta (2)-adrenoceptor agonist act synergistically in vivo.

Lung‐specific nuclear reprogramming is accompanied by heterokaryon formation and Y chromosome loss following bone marrow transplantation and secondary inflammation

Cell fusion is one mechanism by which bone marrow-derived cells (BMDCs) take on the gene expression pattern of nonhematopoietic cells. This process occurs in a number of organs with postengraftment injury but has never been found in the lung. We performed bone marrow (BM) transplant in a murine model of lung inflammation to test whether transplanted BMDCs develop lung-specific gene expression by fusing with diseased pneumocytes. Mice lacking the lung-specific protein surfactant protein C (Sp-C) were lethally irradiated, transplanted with sex mismatched wild-type marrow, and sacrificed 6 months later. Nineteen/38 recipients exhibited Sp-C mRNA (RT-PCR) and/or protein (mean 0.95+/-1.18 Sp-C+ cells per 1000 type II pneumocytes by confocal microscopy). In male recipients of female BM, 65% of Sp-C + cells contained the Y chromosome, indicating their origin from fusion. Only 28% of Sp-C+ cells in female recipients of male BMDCs contained the Y chromosome, suggesting that 72% of Sp-C-expressing cells lost the Y chromosome. In the setting of post-transplant inflammation, pneumocyte-specific reprogramming of transplanted BMDCs predominantly derives from heterokaryon formation. This process does not reverse inflammation caused by Sp-C deficiency; nevertheless, further investigation may identify phenotypes benefiting from such an approach.

Pulmonary Exposure to Diesel Exhaust Particle Components Enhances Circulatory Chemokines during Lung Inflammation

This study examines the effects of DEP components on circulatory CC and CXC chemokines, potent activators and chemoattractants for macrophage and leukocyte subpopulations, in a murine model of lung inflammation. ICR mice were divided into six experimental groups which received intratracheal inoculation of vehicle, LPS alone (2.5 mg/kg), organic chemicals in DEP (DEP-OC: 4 mg/kg) extracted with dichloromethane, residual carbonaceous nuclei after the extraction (washed DEP: 4 mg/kg), DEP-OC + LPS, or washed DEP + LPS. Intratracheal instillation of each DEP component alone did not significantly change the circulatory level of macrophage inflammatory protein (MIP)-1alpha, MIP-2, and macrophage chemoattractant protein-1 (MCP-1) 24 h after the exposure as compared with vehicle instilled alone. In the LPS group, MCP-1, but not MIP-1alpha or MIP-2, was significantly greater than in the vehicle group. The combined administration of LPS and washed DEP caused a further three to five-fold increase in MIP-1alpha, MIP-2, and MCP-1 proteins in the serum as compared with LPS administered alone. No significant difference between the LPS + DEP-OC group and the LPS group was observed. These results indicate that pulmonary exposure to washed DEP enhances circulatory level of chemokines during lung inflammation. The enhancement may be important in the aggravations of systemic inflammatory responses and ischemic cardiovascular conditions associated with air pollution.

The murine bronchopulmonary microcirculation in hapten-induced inflammation

The clinical observation of central bronchial artery hypertrophy in chronic lung inflammation suggests the possibility that the bronchial circulation may also participate in adaptive responses in peripheral lung inflammation. To investigate the potential role of the bronchial microcirculation in peripheral lung inflammation, we developed a murine model of lung inflammation using the intratracheal instillation of the peptide-hapten trinitrophenol in presensitized mice. Clinical parameters indicated a peak inflammatory response at 96 hours. Similarly, gross and microscopic evidence of inflammation was observed 96 hours after antigen instillation. Using a forced oscillation technique to probe peripheral lung mechanics at 96 hours, we detected no change in central airway resistance (P > .05), but a significant increase in peripheral tissue resistance (P < .05). The structure of the bronchial circulation was investigated by microsphere occlusion of the pulmonary circulation and corrosion casting of the bronchial circulation. SEM of the bronchial artery casts demonstrated (1) the presence of the peripheral bronchial circulation in mice, (2) interconnections of the two systems in the distal bronchial arteries and at the level of alveolar capillaries, and (3) functional evidence of increased bronchial perfusion of alveolar capillaries during mononuclear inflammation. These results suggest an important adaptive role of the bronchial circulation in pulmonary inflammation.