Cytokine Expression In Lung Tissue Research Articles

Aryl Hydrocarbon Receptor Activation in Pulmonary Alveolar Epithelial Cells Limits Inflammation and Preserves Lung Epithelial Cell Integrity.

The aryl hydrocarbon receptor (AHR) is a receptor/transcription factor widely expressed in the lung. The physiological roles of AHR expressed in the alveolar epithelium remain unclear. In this study, we tested the hypothesis that alveolar epithelial AHR activity plays an important role in modulating inflammatory responses and maintaining alveolar integrity during lung injury and repair. AHR is expressed in alveolar epithelial cells (AECs) and is active. AHR activation with the endogenous AHR ligand, FICZ (5,11-dihydroindolo[3,2-b] carbazole-6-carboxaldehyde), significantly suppressed inflammatory cytokine expression in response to inflammatory stimuli in primary murine AECs and in the MLE-15 epithelial cell line. In an LPS model of acute lung injury in mice, coadministration of FICZ with LPS suppressed protein leak, reduced neutrophil accumulation in BAL fluid, and suppressed inflammatory cytokine expression in lung tissue and BAL fluid. Relevant to healing following inflammatory injury, AHR activation suppressed TGF-β-induced expression of genes associated with epithelial-mesenchymal transition. Knockdown of AHR in primary AECs with shRNA or in CRISPR-Cas-9-induced MLE-15 cells resulted in upregulation of α-smooth muscle actin (αSma), Col1a1, and Fn1 and reduced expression of epithelial genes Col4a1 and Sdc1. MLE-15 clones lacking AHR demonstrated accelerated wound closure in a scratch model. AHR activation with FICZ enhanced barrier function (transepithelial electrical resistance) in primary murine AECs and limited decline of transepithelial electrical resistance following inflammatory injury. AHR activation in AECs preserves alveolar integrity by modulating inflammatory cytokine expression while enhancing barrier function and limiting stress-induced expression of mesenchymal genes.

Abstract 5848: Fucoidan adminstration attenuates radiation pneumonitis and fibrosis through reducing inflammatory cytokine expression in lung tissue

Abstract Purpose: There is no well-known compound to prevent radiation pneumonitis (RP) or prophylactically use to attenuate the toxicity of RP. RP is one of major complications in chest part irradiation and limitations of radiation dose. Fucoidan is a sulfated polysaccharide found mainly in various species of brown algae and brown seaweed. Recent studies have demonstrated its anti-inflammation effect. Since RP is an radiation induced inflammatory and fibrosis related complication, we investigated the effect of fucoidan adminstration on radiation pneumonitis and fibrosis. Materials and Methods: In this study, we compared the pneumonitis and fibrosis in lung tissue specimen between the lungs irradiated (10Gy/one shot) C57BL/6 mice with or without Fucoidan adminstration (200mg/kg /day, oral gavage for 14 days). Results: The results demonstrated that fucoidan adminstration attenuates pneumonitis and fibrosis in lung tissue. We found the accumulation of neutrophils in irradiated lung tissue was decreased, and the radiation induced Masson trichrome staining fibrosis was decreased. We also investigate the inflammatory -cytokine profiles in the irradiated lung tissue by protein array. The results revealed that fucoidan adminstration changes the inflammatory -cytokine expression pattern in in the irradiated lung tissue. Conclusions: This study demonstrated that inflammatory -cytokine expression after whole lung irradiation is correlated with neutrophil accumulation and radiation induced fibrosis. Interestingly, Fucoidan adminstration changes the inflammatory -cytokine expression pattern which may lead to attenuates radiation pneumonitis and fibrosis. It is potential to be a therapeutic molecular to attenuate or prevent radiation pneumonitis. Note: This abstract was not presented at the meeting. Citation Format: Szu-Yuan Wu. Fucoidan adminstration attenuates radiation pneumonitis and fibrosis through reducing inflammatory cytokine expression in lung tissue [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5848. doi:10.1158/1538-7445.AM2017-5848

Inflammatory, anti-inflammatory and regulatory cytokines in relatively healthy lung tissue as an essential part of the local immune system.

The innate and adaptive immune systems in lungs are maintained not only by immune cells but also by non-immune tissue structures, locally providing wide intercellular communication networks and regulating the local tissue immune response. The aim of this study was to determine the appearance and distribution of inflammatory, anti-inflammatory and regulatory cytokines in relatively healthy lung tissue samples. We evaluated lung tissue specimens obtained from 49 patients aged 9-95 years in relatively healthy study subjects. Tissue samples were examined by hematoxylin and eosin staining. Interleukin-1 (IL-1), interleukin-4 (IL-4), interleukin-6 (IL-6), interleukin-7 (IL-7), and interleukin-10 (IL-10) were detected by an immunohistochemistry (IMH) method. The number of positive structures was counted semiquantitatively by microscopy. Non-parametric tests were used to analyse the data. IL-1-positive cells were mostly found in the bronchial cartilage and alveolar epithelium. Immunoreactive lung macrophages were also found. The numbers of IL-4, IL-6, IL-7, and IL-10 containing cells were also found in the bronchial epithelium (in addition to those previously listed). The number of positive structures varied from occasional to moderate, but was graded higher in cartilage. Overall, fewer IL-1-positive cells and more IL-10-positive cells were found. Almost no positive structures for all examined cytokines were found in connective tissue and bronchial glands. Relatively healthy lung tissue exhibits anti-inflammatory response patterns. The cytokine distribution and appearance suggest persistent stimulation of cytokine expression in lung tissue and indicate the presence of local regulatory and modulating patterns. The pronounced cytokine distribution in bronchial cartilage suggests the involvement of a compensatory local immune response in the supporting tissue.

Acetaminophen Attenuates House Dust Mite-Induced Allergic Airway Disease in Mice.

Epidemiologic evidence suggests that N-acetyl-para-aminophenol (APAP) may play a role in the pathogenesis of asthma, likely through pro-oxidant mechanisms. However, no studies have investigated the direct effects of APAP on the development of allergic inflammation. To determine the likelihood of a causal relationship between APAP and asthma pathogenesis, we explored the effects of APAP on inflammatory responses in a murine house dust mite (HDM) model of allergic airway disease. We hypothesized that APAP would enhance the development of HDM-induced allergic inflammation. The HDM model consisted of once daily intranasal instillations for up to 2 weeks with APAP or vehicle administration 1 hour prior to HDM during either week 1 or 2. Primary assessment of inflammation included bronchoalveolar lavage (BAL), cytokine expression in lung tissue, and histopathology. Contrary to our hypothesis, the effects of HDM treatment were substantially diminished in APAP-treated groups compared with controls. APAP-treated groups had markedly reduced airway inflammation: including decreased inflammatory cells in the BAL fluid, lower cytokine expression in lung tissue, and less perivascular and peribronchiolar immune cell infiltration. The anti-inflammatory effect of APAP was not abrogated by an inhibitor of cytochrome P450 (P450) metabolism, suggesting that the effect was due to the parent compound or a non-P450 generated metabolite. Taken together, our studies do not support the biologic plausibility of the APAP hypothesis that APAP use may contribute to the causation of asthma. Importantly, we suggest the mechanism by which APAP modulates airway inflammation may provide novel therapeutic targets for asthma.

Modulation of radiation-induced alterations in oxidative stress and cytokine expression in lung tissue by Panax ginseng extract.

We investigated the modulating effect of Panax ginseng extract (PGE) on radiation-induced lung injury (RILI) by measuring early changes in oxidative stress levels, cytokine expression, and the histopathology of mouse lung tissue treated with high dose of X-ray radiation. The mice were pretreated with 25, 50, and 100-mg/kg doses of PGE orally for four consecutive days, and their thoraces were then exposed to 15-Gy X-ray radiation 1 h after the last administration of PGE on day 4. The pretreatments with 50 and 100 mg/kg PGE led to significant reductions in the elevation of lipid peroxidation levels at 2 and 10 days, respectively, after irradiation. The mice pretreated with PGE exhibited dose-dependent reductions in the irradiation-induced production of tumor necrosis factor α and transforming growth factor β1 cytokines 10 days after irradiation, with these reductions nearly reaching the control levels after the 100-mg/kg dose. Furthermore, together with providing significant protection against reductions in catalase activity and glutathione content, pretreatment with 100 mg/kg PGE resulted in a marked attenuation of the severity of inflammatory changes in lung tissue 10 days after irradiation. A high pretreatment dose of PGE may be a useful pharmacological approach for protection against RILI.

Carbon capture and sequestration: an exploratory inhalation toxicity assessment of amine-trapping solvents and their degradation products.

Carbon dioxide (CO2) absorption with aqueous amine solvents is a method of carbon capture and sequestration (CCS) from flue gases. One concern is the possible release of amine solvents and degradation products into the atmosphere, warranting evaluation of potential pulmonary effects from inhalation. The CCS amines monoethanolamine (MEA), methyldiethanolamine (MDEA), and piperazine (PIP) underwent oxidative and CO2-mediated degradation for 75 days. C57bl/6N mice were exposed for 7 days by inhalation of 25 ppm neat amine or equivalant concentration in the degraded mixture. The aqueous solutions were nebulized to create the inhalation atmospheres. Pulmonary response was measured by changes in inflammatory cells in bronchoalveolar lavage fluid and cytokine expression in lung tissue. Ames mutagenicity and CHO-K1 micronucleus assays were applied to assess genotoxicity. Chemical analysis of the test atmosphere and liquid revealed complex mixtures, including acids, aldehydes, and other compounds. Exposure to oxidatively degraded MEA increased (p < 0.05) total cells, neutrophils, and lymphocytes compared to control mice and caused inflammatory cytokine expression (statistical increase at p < 0.05). MEA and CO2-degraded MEA were the only atmospheres to show statistical (p < 0.05) increase in oxidative stress. CO2 degradation resulted in a different composition, less degradation, and lower observed toxicity (less magnitude and number of effects) with no genotoxicity. Overall, oxidative degradation of the amines studied resulted in enhanced toxicity (increased magnitude and number of effects) compared to the neat chemicals.

The role of PPARγ in carbon nanotube-elicited granulomatous lung inflammation

BackgroundAlthough granulomatous inflammation is a central feature of many disease processes, cellular mechanisms of granuloma formation and persistence are poorly understood. Carbon nanoparticles, which can be products of manufacture or the environment, have been associated with granulomatous disease. This paper utilizes a previously described carbon nanoparticle granuloma model to address the issue of whether peroxisome proliferator-activated receptor gamma (PPARγ), a nuclear transcription factor and negative regulator of inflammatory cytokines might play a role in granulomatous lung disease. PPARγ is constitutively expressed in alveolar macrophages from healthy individuals but is depressed in alveolar macrophages of patients with sarcoidosis, a prototypical granulomatous disease. Our previous study of macrophage-specific PPARγ KO mice had revealed an intrinsically inflammatory pulmonary environment with an elevated pro-inflammatory cytokines profile as compared to wild-type mice. Based on such observations we hypothesized that PPARγ expression would be repressed in alveolar macrophages from animals bearing granulomas induced by MWCNT instillation.MethodsWild-type C57Bl/6 and macrophage-specific PPARγ KO mice received oropharyngeal instillations of multiwall carbon nanotubes (MWCNT) (100 μg). Bronchoalveolar lavage (BAL) cells, BAL fluids, and lung tissues were obtained 60 days post-instillation for analysis of granuloma histology and pro-inflammatory cytokines (osteopontin, CCL2, and interferon gamma [IFN-γ] mRNA and protein expression.ResultsIn wild-type mice, alveolar macrophage PPARγ expression and activity were significantly reduced in granuloma-bearing animals 60 days after MWCNT instillation. In macrophage-specific PPARγ KO mice, granuloma formation was more extensive than in wild-type at 60 days after MWCNT instillation. PPARγ KO mice also demonstrated elevated pro-inflammatory cytokine expression in lung tissue, laser-microdissected lung granulomas, and BAL cells/fluids, at 60 days post MWCNT exposure.ConclusionsOverall, data indicate that PPARγ deficiency promotes inflammation and granuloma formation, suggesting that PPARγ functions as a negative regulator of chronic granulomatous inflammation.

312 Low Dose Lipopolysaccharide (LPS) Exposure Potentiates High-Tidal Volume Ventilation (HTVV)-Induced Proinflammatory Cytokine Expression in Newborn Rat

Background: Proinflammatory cytokines are associated with increased risk of chronic lung disease in premature patients. Chorioamnionitis as well as mechanical ventilation have been shown to increase cytokine expression in lung tissue and blood. Objective: To test the hypothesis that low-dose LPS exposure would modify the cytokine response to HTVV in newborn rats. Methods: Newborn (3–6 days) rats were randomly assigned to four groups (I-IV: 12–14 animals/group). Group III and IV were injected 24h prior ventilation with 3 mg LPS/kg while I and II received saline. Group II and IV were subjected to HTVV (25ml/kg, 60/min, 3h). Lung IL-6, MIP-2, IL-1beta and TNF-alpha mRNA was determined by realtime RT-PCR. Cytokine protein content was measured in bronchoalveolar lavage fluid (BALF). Statistical analysis: one-way ANOVA and t-test (significance: p<0.05). Results: LPS injection reduced weight gain within the 24h following injection from 17.9% (saline) to 11.4% (p<0.05). Pre-treatment with LPS did neither affect lung compliance nor blood gas values. LPS alone did not change cytokine expression. In contrast, HTVV alone increased mRNA expression of IL-6 by 7.2 fold, MIP-2 by 7.9 fold and IL-1beta by 1.8 fold (p<0.05). The combination of HTVV and LPS further increased the expression of IL-6 (II vs IV; 10.5 fold) and IL-1beta (II vs IV; 2.3 fold). IL-6 protein content in BALF increased with HTVV and LPS+HTVV treatments (I 19.4, II 34.0, III 17.5, IV 43.7 pg/ml). Conclusions: Whereas low grade systemic inflammation alone does not change the proinflammatory cytokine expression, its combination with HTVV potentiates the proinflammatory cytokine response in the newborn lung. Therefore, we speculate that newborn patients born in a context of chorioamnionitis are at higher risk to develop ventilator associated lung injury than those without association with inflammation/infection.

LUNG INFLAMMATION INDUCED BY ENDOTOXIN IS ENHANCED IN RATS DEPLETED OF ALVEOLAR MACROPHAGES WITH AEROSOLIZED CLODRONATE

Clodronate liposomes were given to rats via intratracheal inhalation to investigate the importance of alveolar macrophages (AMs) in inhaled endotoxin-induced lung injury. When AM depletion was maximal (87% to 90%), rats were exposed to lipopolysaccharide (LPS) or saline. Neither clodronate nor saline liposomes induced an influx of neutrophils (PMNs) into the lungs. However, depleted LPS-exposed rats had 5- to 8-fold higher numbers of lavage PMNs and greater lavage cell reactive oxygen species release compared to undepleted rats. Although AM depletion by itself did not significantly increase inflammatory cytokine expression in lung tissue, LPS-induced message levels for interleukin (IL)-1α, IL-1β, IL-6, and tumor necrosis factor (TNF)-α were approximately 2-fold higher in AM-depleted rats compared to undepleted rats. These results indicate that cells other than AMs can recruit inflammatory cells into the lungs during acute LPS-induced injury and that AMs play an important suppressive role in the innate pulmonary inflammatory response.