Limits...
Macrophage-expressed IFN-β contributes to apoptotic alveolar epithelial cell injury in severe influenza virus pneumonia.

Högner K, Wolff T, Pleschka S, Plog S, Gruber AD, Kalinke U, Walmrath HD, Bodner J, Gattenlöhner S, Lewe-Schlosser P, Matrosovich M, Seeger W, Lohmeyer J, Herold S - PLoS Pathog. (2013)

Bottom Line: Bone marrow chimeric mice lacking these signalling mediators in resident and lung-recruited AM and mice subjected to alveolar neutralization of IFN-β and TRAIL displayed reduced alveolar epithelial cell apoptosis and attenuated lung injury during severe IV pneumonia.Together, we demonstrate that macrophage-released type I IFNs, apart from their well-known anti-viral properties, contribute to IV-induced AEC damage and lung injury by autocrine induction of the pro-apoptotic factor TRAIL.Our data suggest that therapeutic targeting of the macrophage IFN-β-TRAIL axis might represent a promising strategy to attenuate IV-induced acute lung injury.

View Article: PubMed Central - PubMed

Affiliation: Department of Internal Medicine II, University of Giessen Lung Center, Giessen, Germany.

ABSTRACT
Influenza viruses (IV) cause pneumonia in humans with progression to lung failure and fatal outcome. Dysregulated release of cytokines including type I interferons (IFNs) has been attributed a crucial role in immune-mediated pulmonary injury during severe IV infection. Using ex vivo and in vivo IV infection models, we demonstrate that alveolar macrophage (AM)-expressed IFN-β significantly contributes to IV-induced alveolar epithelial cell (AEC) injury by autocrine induction of the pro-apoptotic factor TNF-related apoptosis-inducing ligand (TRAIL). Of note, TRAIL was highly upregulated in and released from AM of patients with pandemic H1N1 IV-induced acute lung injury. Elucidating the cell-specific underlying signalling pathways revealed that IV infection induced IFN-β release in AM in a protein kinase R- (PKR-) and NF-κB-dependent way. Bone marrow chimeric mice lacking these signalling mediators in resident and lung-recruited AM and mice subjected to alveolar neutralization of IFN-β and TRAIL displayed reduced alveolar epithelial cell apoptosis and attenuated lung injury during severe IV pneumonia. Together, we demonstrate that macrophage-released type I IFNs, apart from their well-known anti-viral properties, contribute to IV-induced AEC damage and lung injury by autocrine induction of the pro-apoptotic factor TRAIL. Our data suggest that therapeutic targeting of the macrophage IFN-β-TRAIL axis might represent a promising strategy to attenuate IV-induced acute lung injury.

Show MeSH

Related in: MedlinePlus

DR5 is upregulated in AEC upon IV infection in an IFN-β-independent way.(A) Primary murine or human AEC were mock- or A/PR8-infected ex vivo and DR5 mRNA expression was quantified 48 h pi. (B) Murine AEC were mock- or A/PR8-infected ex vivo and surface DR5 abundance in infected (NP+) vs. non-infected (NP−) AEC from the same culture was analysed by FACS 48 h pi (representative histogram provided in the left panel) and is depicted as fold MFI (mean fluorescence intensity) of mock-infected cultures (right panel). (C) Murine AEC were stimulated with rIFN-β or vehicle-treated (ctrl) and DR5 mRNA expression was quantified after 6 h and 12 h and is depicted as ΔCT values. (D) DR5 surface expression on AEC from A/PR8-infected wt and ifnar−/− mice was analysed by FACS. Bar graphs represent means ± SD of 4 (A) and 5 (B, C) independent experiments. Bar graphs in D represent means ± SD of animals/group. * p<0,05; ** p<0,01; ***p<0,001; MOI, multiplicity of infection; hAEC, human AEC; mAEC, murine AEC; NP, nucleoprotein; iso, isotype Ab; rIFN-β, recombinant IFN-β.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3585175&req=5

ppat-1003188-g005: DR5 is upregulated in AEC upon IV infection in an IFN-β-independent way.(A) Primary murine or human AEC were mock- or A/PR8-infected ex vivo and DR5 mRNA expression was quantified 48 h pi. (B) Murine AEC were mock- or A/PR8-infected ex vivo and surface DR5 abundance in infected (NP+) vs. non-infected (NP−) AEC from the same culture was analysed by FACS 48 h pi (representative histogram provided in the left panel) and is depicted as fold MFI (mean fluorescence intensity) of mock-infected cultures (right panel). (C) Murine AEC were stimulated with rIFN-β or vehicle-treated (ctrl) and DR5 mRNA expression was quantified after 6 h and 12 h and is depicted as ΔCT values. (D) DR5 surface expression on AEC from A/PR8-infected wt and ifnar−/− mice was analysed by FACS. Bar graphs represent means ± SD of 4 (A) and 5 (B, C) independent experiments. Bar graphs in D represent means ± SD of animals/group. * p<0,05; ** p<0,01; ***p<0,001; MOI, multiplicity of infection; hAEC, human AEC; mAEC, murine AEC; NP, nucleoprotein; iso, isotype Ab; rIFN-β, recombinant IFN-β.

Mentions: To determine whether IV-induced AM-expressed IFN-β might additionally promote TRAIL-induced signalling on receptor level, we next quantified AEC TRAIL receptor (DR5, death receptor 5) expression in mono-cultured AEC. As shown in Fig. 5, DR5 was MOI-dependently upregulated in both murine and human AEC upon ex vivo A/PR8 infection on gene expression level (Fig. 5A). Of note, A/PR8-infected (IV nucleoprotein+, NP+) AEC showed significantly increased DR5 surface expression compared to non-infected (NP−) AEC within the same culture (Fig. 5B). Interestingly, stimulation of AEC with IFN-β did not impact on DR5 gene expression (Fig. 5C), and DR5 surface expression on AEC did not differ between wt and ifnar−/− mice in vivo (Fig. 5D), suggesting that macrophage IFN-β induces target cell apoptosis rather by increased macrophage expression of death receptor ligands than by affecting DR5 levels on AEC. Nonetheless, IV-infection sensitizes AEC for TRAIL-mediated killing through IFN-β-independent DR5 upregulation.


Macrophage-expressed IFN-β contributes to apoptotic alveolar epithelial cell injury in severe influenza virus pneumonia.

Högner K, Wolff T, Pleschka S, Plog S, Gruber AD, Kalinke U, Walmrath HD, Bodner J, Gattenlöhner S, Lewe-Schlosser P, Matrosovich M, Seeger W, Lohmeyer J, Herold S - PLoS Pathog. (2013)

DR5 is upregulated in AEC upon IV infection in an IFN-β-independent way.(A) Primary murine or human AEC were mock- or A/PR8-infected ex vivo and DR5 mRNA expression was quantified 48 h pi. (B) Murine AEC were mock- or A/PR8-infected ex vivo and surface DR5 abundance in infected (NP+) vs. non-infected (NP−) AEC from the same culture was analysed by FACS 48 h pi (representative histogram provided in the left panel) and is depicted as fold MFI (mean fluorescence intensity) of mock-infected cultures (right panel). (C) Murine AEC were stimulated with rIFN-β or vehicle-treated (ctrl) and DR5 mRNA expression was quantified after 6 h and 12 h and is depicted as ΔCT values. (D) DR5 surface expression on AEC from A/PR8-infected wt and ifnar−/− mice was analysed by FACS. Bar graphs represent means ± SD of 4 (A) and 5 (B, C) independent experiments. Bar graphs in D represent means ± SD of animals/group. * p<0,05; ** p<0,01; ***p<0,001; MOI, multiplicity of infection; hAEC, human AEC; mAEC, murine AEC; NP, nucleoprotein; iso, isotype Ab; rIFN-β, recombinant IFN-β.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3585175&req=5

ppat-1003188-g005: DR5 is upregulated in AEC upon IV infection in an IFN-β-independent way.(A) Primary murine or human AEC were mock- or A/PR8-infected ex vivo and DR5 mRNA expression was quantified 48 h pi. (B) Murine AEC were mock- or A/PR8-infected ex vivo and surface DR5 abundance in infected (NP+) vs. non-infected (NP−) AEC from the same culture was analysed by FACS 48 h pi (representative histogram provided in the left panel) and is depicted as fold MFI (mean fluorescence intensity) of mock-infected cultures (right panel). (C) Murine AEC were stimulated with rIFN-β or vehicle-treated (ctrl) and DR5 mRNA expression was quantified after 6 h and 12 h and is depicted as ΔCT values. (D) DR5 surface expression on AEC from A/PR8-infected wt and ifnar−/− mice was analysed by FACS. Bar graphs represent means ± SD of 4 (A) and 5 (B, C) independent experiments. Bar graphs in D represent means ± SD of animals/group. * p<0,05; ** p<0,01; ***p<0,001; MOI, multiplicity of infection; hAEC, human AEC; mAEC, murine AEC; NP, nucleoprotein; iso, isotype Ab; rIFN-β, recombinant IFN-β.
Mentions: To determine whether IV-induced AM-expressed IFN-β might additionally promote TRAIL-induced signalling on receptor level, we next quantified AEC TRAIL receptor (DR5, death receptor 5) expression in mono-cultured AEC. As shown in Fig. 5, DR5 was MOI-dependently upregulated in both murine and human AEC upon ex vivo A/PR8 infection on gene expression level (Fig. 5A). Of note, A/PR8-infected (IV nucleoprotein+, NP+) AEC showed significantly increased DR5 surface expression compared to non-infected (NP−) AEC within the same culture (Fig. 5B). Interestingly, stimulation of AEC with IFN-β did not impact on DR5 gene expression (Fig. 5C), and DR5 surface expression on AEC did not differ between wt and ifnar−/− mice in vivo (Fig. 5D), suggesting that macrophage IFN-β induces target cell apoptosis rather by increased macrophage expression of death receptor ligands than by affecting DR5 levels on AEC. Nonetheless, IV-infection sensitizes AEC for TRAIL-mediated killing through IFN-β-independent DR5 upregulation.

Bottom Line: Bone marrow chimeric mice lacking these signalling mediators in resident and lung-recruited AM and mice subjected to alveolar neutralization of IFN-β and TRAIL displayed reduced alveolar epithelial cell apoptosis and attenuated lung injury during severe IV pneumonia.Together, we demonstrate that macrophage-released type I IFNs, apart from their well-known anti-viral properties, contribute to IV-induced AEC damage and lung injury by autocrine induction of the pro-apoptotic factor TRAIL.Our data suggest that therapeutic targeting of the macrophage IFN-β-TRAIL axis might represent a promising strategy to attenuate IV-induced acute lung injury.

View Article: PubMed Central - PubMed

Affiliation: Department of Internal Medicine II, University of Giessen Lung Center, Giessen, Germany.

ABSTRACT
Influenza viruses (IV) cause pneumonia in humans with progression to lung failure and fatal outcome. Dysregulated release of cytokines including type I interferons (IFNs) has been attributed a crucial role in immune-mediated pulmonary injury during severe IV infection. Using ex vivo and in vivo IV infection models, we demonstrate that alveolar macrophage (AM)-expressed IFN-β significantly contributes to IV-induced alveolar epithelial cell (AEC) injury by autocrine induction of the pro-apoptotic factor TNF-related apoptosis-inducing ligand (TRAIL). Of note, TRAIL was highly upregulated in and released from AM of patients with pandemic H1N1 IV-induced acute lung injury. Elucidating the cell-specific underlying signalling pathways revealed that IV infection induced IFN-β release in AM in a protein kinase R- (PKR-) and NF-κB-dependent way. Bone marrow chimeric mice lacking these signalling mediators in resident and lung-recruited AM and mice subjected to alveolar neutralization of IFN-β and TRAIL displayed reduced alveolar epithelial cell apoptosis and attenuated lung injury during severe IV pneumonia. Together, we demonstrate that macrophage-released type I IFNs, apart from their well-known anti-viral properties, contribute to IV-induced AEC damage and lung injury by autocrine induction of the pro-apoptotic factor TRAIL. Our data suggest that therapeutic targeting of the macrophage IFN-β-TRAIL axis might represent a promising strategy to attenuate IV-induced acute lung injury.

Show MeSH
Related in: MedlinePlus