Preventing carbon nanoparticle-induced lung inflammation reduces antigen-specific sensitization and subsequent allergic reactions in a mouse model

Background Exposure of the airways to carbonaceous nanoparticles can contribute to the development of immune diseases both via the aggravation of the allergic immune response in sensitized individuals and by adjuvant mechanisms during the sensitization against allergens. The cellular and molecular mechanisms involved in these adverse pathways are not completely understood. We recently described that the reduction of carbon nanoparticle-induced lung inflammation by the application of the compatible solute ectoine reduced the aggravation of the allergic response in an animal system. In the current study we investigated the influence of carbon nanoparticles on the sensitization of animals to ovalbumin via the airways. Ectoine was used as a preventive strategy against nanoparticle-induced neutrophilic lung inflammation. Methods Balb/c mice were repetitively exposed to the antigen ovalbumin after induction of airway inflammation by carbon nanoparticles, either in the presence or in the absence of ectoine. Allergic sensitization was monitored by measurement of immunoglobulin levels and immune responses in lung and lung draining lymph nodes after challenge. Furthermore the role of dendritic cells in the effect of carbon nanoparticles was studied in vivo in the lymph nodes but also in vitro using bone marrow derived dendritic cells. Results Animals exposed to antigen in the presence of carbon nanoparticles showed increased effects with respect to ovalbumin sensitization, to the allergic airway inflammation after challenge, and to the specific TH2 response in the lymph nodes. The presence of ectoine during the sensitization significantly reduced these parameters. The number of antigen-loaded dendritic cells in the draining lymph nodes was identified as a possible cause for the adjuvant effect of the nanoparticles. In vitro assays indicate that the direct interaction of the particles with dendritic cells is not able to trigger CCR7 expression, while this endpoint is achieved by lung lavage fluid from nanoparticle-exposed animals. Conclusions Using the intervention strategy of applying ectoine into the airways of animals we were able to demonstrate the relevance of neutrophilic lung inflammation for the adjuvant effect of carbon nanoparticles on allergic sensitization.n

Preventing carbon nanoparticle-induced lung inflammation reduces antigen-specific sensitization and subsequent allergic reactions in a mouse model

BACKGROUND: Exposure of the airways to carbonaceous nanoparticles can contribute to the development of immune diseases both via the aggravation of the allergic immune response in sensitized individuals and by adjuvant mechanisms during the sensitization against allergens. The cellular and molecular mechanisms involved in these adverse pathways are not completely understood. We recently described that the reduction of carbon nanoparticle-induced lung inflammation by the application of the compatible solute ectoine reduced the aggravation of the allergic response in an animal system. In the current study we investigated the influence of carbon nanoparticles on the sensitization of animals to ovalbumin via the airways. Ectoine was used as a preventive strategy against nanoparticle-induced neutrophilic lung inflammation. METHODS: Balb/c mice were repetitively exposed to the antigen ovalbumin after induction of airway inflammation by carbon nanoparticles, either in the presence or in the absence of ectoine. Allergic sensitization was monitored by measurement of immunoglobulin levels and immune responses in lung and lung draining lymph nodes after challenge. Furthermore the role of dendritic cells in the effect of carbon nanoparticles was studied in vivo in the lymph nodes but also in vitro using bone marrow derived dendritic cells. RESULTS: Animals exposed to antigen in the presence of carbon nanoparticles showed increased effects with respect to ovalbumin sensitization, to the allergic airway inflammation after challenge, and to the specific T(H)2 response in the lymph nodes. The presence of ectoine during the sensitization significantly reduced these parameters. The number of antigen-loaded dendritic cells in the draining lymph nodes was identified as a possible cause for the adjuvant effect of the nanoparticles. In vitro assays indicate that the direct interaction of the particles with dendritic cells is not able to trigger CCR7 expression, while this endpoint is achieved by lung lavage fluid from nanoparticle-exposed animals. CONCLUSIONS: Using the intervention strategy of applying ectoine into the airways of animals we were able to demonstrate the relevance of neutrophilic lung inflammation for the adjuvant effect of carbon nanoparticles on allergic sensitization. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12989-015-0093-5) contains supplementary material, which is available to authorized users

Reduction of neutrophilic lung inflammation by inhalation of the compatible solute ectoine: a randomized trial with elderly individuals

BACKGROUND: Compatible solutes are natural substances that are known to stabilize cellular functions. Preliminary ex vivo and in vivo studies demonstrated that the compatible solute ectoine restores natural apoptosis rates of lung neutrophils and contributes to the resolution of lung inflammation. Due to the low toxicity and known compatibility of the substance, an inhalative application as an intervention strategy for humans suffering from diseases caused by neutrophilic inflammation, like COPD, had been suggested. As a first approach to test the feasibility and efficacy of such a treatment, we performed a population-based randomized trial. OBJECTIVE: The objective of the study was to test whether the daily inhalation of the registered ectoine-containing medical device (Ectoin® inhalation solution) leads to a reduction of neutrophilic cells and interleukin-8 (IL-8) levels in the sputum of persons with mild symptoms of airway disease due to lifelong exposure to environmental air pollution. METHODS: A double-blinded placebo-controlled trial was performed to study the efficacy and safety of an ectoine-containing therapeutic. Prior to and after both inhalation periods, lung function, inflammatory parameters in sputum, serum markers, and quality-of-life parameters were determined. RESULTS: While the other outcomes revealed no significant effects, sputum parameters were changed by the intervention. Nitrogen oxides (nitrate and nitrite) were significantly reduced after ectoine inhalation with a mean quotient of 0.65 (95% confidence interval 0.45–0.93). Extended analyses considering period effects revealed that the percentage of neutrophils in sputum was significantly lower after ectoine inhalation than in the placebo group (P=0.035) even after the washout phase. CONCLUSION: The current study is the first human trial in which the effects of inhaled ectoine on neutrophilic lung inflammation were investigated. Besides demonstrating beneficial effects on inflammatory sputum parameters, the study proves the feasibility of the therapeutic approach in an aged study group

Carbon nanoparticles induce ceramide- and lipid raft-dependent signalling in lung epithelial cells: a target for a preventive strategy against environmentally-induced lung inflammation

Abstract Background Particulate air pollution in lung epithelial cells induces pathogenic endpoints like proliferation, apoptosis, and pro-inflammatory reactions. The activation of the epidermal growth factor receptor (EGFR) is a key event responsible for signalling events involving mitogen activated protein kinases specific for these endpoints. The molecular events leading to receptor activation however are not well understood. These events are relevant for the toxicological evaluation of inhalable particles as well as for potential preventive strategies in situations when particulate air pollution cannot be avoided. The current study therefore had the objective to elucidate membrane-coupled events leading to EGFR activation and the subsequent signalling cascade in lung epithelial cells. Furthermore, we aimed to identify the molecular target of ectoine, a biophysical active substance which we described to prevent carbon nanoparticle-induced lung inflammation. Methods Membrane signalling events were investigated in isolated lipid rafts from lung epithelial cells with regard to lipid and protein content of the signalling platforms. Using positive and negative intervention approaches, lipid raft changes, subsequent signalling events, and lung inflammation were investigated in vitro in lung epithelial cells (RLE-6TN) and in vivo in exposed animals. Results Carbon nanoparticle treatment specifically led to an accumulation of ceramides in lipid rafts. Detailed analyses demonstrated a causal link of ceramides and subsequent EGFR activation coupled with a loss of the receptor in the lipid raft fractions. In vitro and in vivo investigations demonstrate the relevance of these events for carbon nanoparticle-induced lung inflammation. Moreover, the compatible solute ectoine was able to prevent ceramide-mediated EGFR phosphorylation and subsequent signalling as well as lung inflammation in vivo. Conclusion The data identify a so far unknown event in pro-inflammatory signalling and contribute to the understanding of particle cell interaction and therefore to risk identification and risk assessment of inhalable xenobiotics. Moreover, as this cellular reaction can be prevented by the well tolerated substance ectoine, a molecular preventive strategy for susceptible persons against airway inflammation is proposed.</p

Signalling-dependent adverse health effects of carbon nanoparticles are prevented by the compatible solute mannosylglycerate (firoin) in vitro and in vivo.

The inhalation of combustion-derived nanoparticles leads to adverse health effects in the airways. In this context the induction of membrane-coupled signalling is considered as causative for changes in tissue homeostasis and pro-inflammatory reactions. The identification of these molecular cell reactions allowed to seek for strategies which interfere with these adverse effects. In the current study, we investigated the structurally different compatible solutes mannosylglycerate (firoin) from thermophilic bacteria and ectoine from halophilic bacteria for their capability to reduce signalling pathways triggered by carbon nanoparticles in target cells in the lung. The pre-treatment of lung epithelial cells with both substances decreased the particle-specific activation of mitogen-activated protein kinases and also the endpoints proliferation and apoptosis. Firoin applied into the lungs of animals, like ectoine, led to a significant reduction of the neutrophilic lung inflammation induced by particle exposure. The pro-inflammatory effect of carbon nanoparticles on human neutrophil granulocytes ex vivo was significantly reduced by both substances via the reduction of the anti-apoptotic membrane-dependent signalling. The data of this study together with earlier studies demonstrate that two structurally non-related compatible solutes are able to prevent pathogenic reactions of the airways to carbon nanoparticles by interfering with signalling events. The findings highlight the preventive or therapeutic potential of compatible solutes for adverse health effects caused by particle exposure of the airways

Recovery of neutrophil apoptosis by ectoine: a new strategy against lung inflammation

The life span of neutrophilic granulocytes has determining impact on the intensity and duration of neutrophil driven lung inflammation. Based on the compatible solute ectoine, we aimed to prevent anti-apoptotic reactions in neutrophils triggered by the inflammatory microenvironment in the lung. Neutrophils from COPD patients and control individuals were exposed to inflammatory mediators and xenobiotics in the presence or absence of ectoine. The in vivo relevance of this approach was tested in xenobiotic-induced lung inflammation in rats. The reduction of apoptosis rates of ex vivo exposed neutrophils from persons of all study groups was significantly restored in the presence of ectoine. However, natural apoptosis rates not altered by inflammatory stimuli were not changed by ectoine. Mechanistic analyses demonstrated the preventive effect of ectoine on the induction of anti-apoptotic signalling. Neutrophilic lung inflammation induced by single or multiple exposition of animals to environmental particles was reduced after the therapeutic intervention with ectoine. Analyses of neutrophils from bronchoalveolar lavage indicate that the in vivo effect is due to the restoration of neutrophil apoptosis. Ectoine, a compound of the highly compliant group of compatible solutes, demonstrates a reproducible and robust effect on the resolution of lung inflammation.</p