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

Kroker M, Sydlik U, Autengruber A, Cavelius C, Weighardt H, Kraegeloh A, Unfried K - Part Fibre Toxicol (2015)

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

Affiliation: IUF - Leibniz Institut für Umweltmedizinische Forschung, Auf'm Hennekamp 50, 40225, Düsseldorf, Germany.

ABSTRACT

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.

No MeSH data available.


Related in: MedlinePlus

Ectoine application reduces the frequency of antigen loaded dendritic cells in lymph nodes. a Animals (n = 3 in control groups, n = 8 in exposure groups) were exposed to 50 μg Alexa Fluor 488-labelled OVA 12 h after the application of PBS (control), CNP, or CNP + E. In order to control for effects of labelled OVA, an additional PBS group without OVA was employed. b BAL cell numbers (means, SEM) 36 h after initial treatment. c Total lymph node cells. d Percentage of OVA-488 positive dendritic cells (MHCII+, CD11c+). e. Percentage of OVA-488 positive macrophages (MHCII+, F4/80+). *significant differences were observed in total cell numbers, neutrophil numbers, and percentage of OVA-488 positive dendritic cells (p < 0.05, Mann Whitney U-test)
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Fig4: Ectoine application reduces the frequency of antigen loaded dendritic cells in lymph nodes. a Animals (n = 3 in control groups, n = 8 in exposure groups) were exposed to 50 μg Alexa Fluor 488-labelled OVA 12 h after the application of PBS (control), CNP, or CNP + E. In order to control for effects of labelled OVA, an additional PBS group without OVA was employed. b BAL cell numbers (means, SEM) 36 h after initial treatment. c Total lymph node cells. d Percentage of OVA-488 positive dendritic cells (MHCII+, CD11c+). e. Percentage of OVA-488 positive macrophages (MHCII+, F4/80+). *significant differences were observed in total cell numbers, neutrophil numbers, and percentage of OVA-488 positive dendritic cells (p < 0.05, Mann Whitney U-test)

Mentions: The data presented so far demonstrate a strong adjuvant effect of CNP on the process of sensitization against the allergen OVA via the airways. The reduction of the neutrophilic lung inflammation by ectoine application during sensitization suggests that this adjuvant effect is driven by the lung inflammation. Since the immune response in the lung draining lymph nodes is also affected by the exposure to CNP, it could be possible that CNP also directly interact with antigen presenting cells and trigger an immune response besides their capacity to induce a neutrophilic inflammation in the lung. This hypothesis is supported by the finding that CD4+ cell proliferation is enhanced in peribronchial lymph nodes after CNP application to the airways in a concentration which appeared not to induce accelerated neutrophil numbers in BAL [25]. Additional data of the same study suggest that the number of antigen presenting dendritic cells is increased by the particle application. We therefore aimed to investigate the role of antigen presenting cells after CNP and ectoine application. In an additional animal experiment, the effects of CNP and ectoine on macrophages and dendritic cells, which are identified as the cell types which transport antigen from the airways to the lymph nodes [26, 27], were investigated (Fig. 4). At the peak of neutrophilic inflammation the fluorescently-labelled antigen (OVA-Alexa Fluor 488) was applied to the airways via pharyngeal aspiration in order to track migrating cells from the lung to the lymph nodes. In order to control for effects of labelled OVA, an additional PBS group without OVA was employed. After 36 h, lung inflammation was determined in BAL and peribronchial lymph nodes were analysed for the presence of antigen carrying cells. Also under these experimental conditions CNP led to an enhanced accumulation of neutrophils in the BAL, while there was an attenuated neutrophil influx after ectoine application (Fig. 4b). This effect was not observed at the level of total lymph node cell numbers (Fig. 4c). Among the dendritic cells (MHCII+/CD11c+) present in the lymph node, an increased number of OVA-488+ cells was observed when the antigen was applied during an ongoing CNP-triggered inflammation (Fig. 4d). This effect was significantly reduced in the presence of ectoine. Only a very low percentage of macrophages (MHCII+/F4/80+) was shown to be OVA-488 positive and no effect of the ectoine treatment was observed for this cell type (Fig. 4e). Thus, CNP seem to enhance the migration of antigen loaded dendritic cells to the draining lymph nodes and ectoine appears to prevent this effect either via direct action on dendritic cells or via the suppression of the neutrophilic inflammation.Fig. 4


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

Kroker M, Sydlik U, Autengruber A, Cavelius C, Weighardt H, Kraegeloh A, Unfried K - Part Fibre Toxicol (2015)

Ectoine application reduces the frequency of antigen loaded dendritic cells in lymph nodes. a Animals (n = 3 in control groups, n = 8 in exposure groups) were exposed to 50 μg Alexa Fluor 488-labelled OVA 12 h after the application of PBS (control), CNP, or CNP + E. In order to control for effects of labelled OVA, an additional PBS group without OVA was employed. b BAL cell numbers (means, SEM) 36 h after initial treatment. c Total lymph node cells. d Percentage of OVA-488 positive dendritic cells (MHCII+, CD11c+). e. Percentage of OVA-488 positive macrophages (MHCII+, F4/80+). *significant differences were observed in total cell numbers, neutrophil numbers, and percentage of OVA-488 positive dendritic cells (p < 0.05, Mann Whitney U-test)
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4491258&req=5

Fig4: Ectoine application reduces the frequency of antigen loaded dendritic cells in lymph nodes. a Animals (n = 3 in control groups, n = 8 in exposure groups) were exposed to 50 μg Alexa Fluor 488-labelled OVA 12 h after the application of PBS (control), CNP, or CNP + E. In order to control for effects of labelled OVA, an additional PBS group without OVA was employed. b BAL cell numbers (means, SEM) 36 h after initial treatment. c Total lymph node cells. d Percentage of OVA-488 positive dendritic cells (MHCII+, CD11c+). e. Percentage of OVA-488 positive macrophages (MHCII+, F4/80+). *significant differences were observed in total cell numbers, neutrophil numbers, and percentage of OVA-488 positive dendritic cells (p < 0.05, Mann Whitney U-test)
Mentions: The data presented so far demonstrate a strong adjuvant effect of CNP on the process of sensitization against the allergen OVA via the airways. The reduction of the neutrophilic lung inflammation by ectoine application during sensitization suggests that this adjuvant effect is driven by the lung inflammation. Since the immune response in the lung draining lymph nodes is also affected by the exposure to CNP, it could be possible that CNP also directly interact with antigen presenting cells and trigger an immune response besides their capacity to induce a neutrophilic inflammation in the lung. This hypothesis is supported by the finding that CD4+ cell proliferation is enhanced in peribronchial lymph nodes after CNP application to the airways in a concentration which appeared not to induce accelerated neutrophil numbers in BAL [25]. Additional data of the same study suggest that the number of antigen presenting dendritic cells is increased by the particle application. We therefore aimed to investigate the role of antigen presenting cells after CNP and ectoine application. In an additional animal experiment, the effects of CNP and ectoine on macrophages and dendritic cells, which are identified as the cell types which transport antigen from the airways to the lymph nodes [26, 27], were investigated (Fig. 4). At the peak of neutrophilic inflammation the fluorescently-labelled antigen (OVA-Alexa Fluor 488) was applied to the airways via pharyngeal aspiration in order to track migrating cells from the lung to the lymph nodes. In order to control for effects of labelled OVA, an additional PBS group without OVA was employed. After 36 h, lung inflammation was determined in BAL and peribronchial lymph nodes were analysed for the presence of antigen carrying cells. Also under these experimental conditions CNP led to an enhanced accumulation of neutrophils in the BAL, while there was an attenuated neutrophil influx after ectoine application (Fig. 4b). This effect was not observed at the level of total lymph node cell numbers (Fig. 4c). Among the dendritic cells (MHCII+/CD11c+) present in the lymph node, an increased number of OVA-488+ cells was observed when the antigen was applied during an ongoing CNP-triggered inflammation (Fig. 4d). This effect was significantly reduced in the presence of ectoine. Only a very low percentage of macrophages (MHCII+/F4/80+) was shown to be OVA-488 positive and no effect of the ectoine treatment was observed for this cell type (Fig. 4e). Thus, CNP seem to enhance the migration of antigen loaded dendritic cells to the draining lymph nodes and ectoine appears to prevent this effect either via direct action on dendritic cells or via the suppression of the neutrophilic inflammation.Fig. 4

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

Affiliation: IUF - Leibniz Institut für Umweltmedizinische Forschung, Auf'm Hennekamp 50, 40225, Düsseldorf, Germany.

ABSTRACT

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.

No MeSH data available.


Related in: MedlinePlus