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Vimentin regulates activation of the NLRP3 inflammasome.

dos Santos G, Rogel MR, Baker MA, Troken JR, Urich D, Morales-Nebreda L, Sennello JA, Kutuzov MA, Sitikov A, Davis JM, Lam AP, Cheresh P, Kamp D, Shumaker DK, Budinger GR, Ridge KM - Nat Commun (2015)

Bottom Line: Activation of the NLRP3 inflammasome and subsequent maturation of IL-1β have been implicated in acute lung injury (ALI), resulting in inflammation and fibrosis.Furthermore, decreased active caspase-1 and IL-1β levels are observed in vitro in Vim(-/-) and vimentin-knockdown macrophages.This study provides insights into lung inflammation and fibrosis and suggests that vimentin may be a key regulator of the NLRP3 inflammasome.

View Article: PubMed Central - PubMed

Affiliation: Division of Pulmonary and Critical Care Medicine, Northwestern University, Chicago, Illinois 60611, USA.

ABSTRACT
Activation of the NLRP3 inflammasome and subsequent maturation of IL-1β have been implicated in acute lung injury (ALI), resulting in inflammation and fibrosis. We investigated the role of vimentin, a type III intermediate filament, in this process using three well-characterized murine models of ALI known to require NLRP3 inflammasome activation. We demonstrate that central pathophysiologic events in ALI (inflammation, IL-1β levels, endothelial and alveolar epithelial barrier permeability, remodelling and fibrosis) are attenuated in the lungs of Vim(-/-) mice challenged with LPS, bleomycin and asbestos. Bone marrow chimeric mice lacking vimentin have reduced IL-1β levels and attenuated lung injury and fibrosis following bleomycin exposure. Furthermore, decreased active caspase-1 and IL-1β levels are observed in vitro in Vim(-/-) and vimentin-knockdown macrophages. Importantly, we show direct protein-protein interaction between NLRP3 and vimentin. This study provides insights into lung inflammation and fibrosis and suggests that vimentin may be a key regulator of the NLRP3 inflammasome.

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Lung injury and fibrosis are attenuated in Vim-/- bone marrow chimeric mice(A) Treatment protocol: CD45.1+ WT mice were lethally irradiated (6 Gy) and two sets of mice were transplanted either with 1×106 CD45.2+ WT or Vim-/- BM cells to generate chimeric mice. 6.5w later, when >90% of AM were of donor (WT and Vim-/-) phenotype, chimeric mice were treated with saline or bleomycin and subjected to analyses. Bleomycin-induced lung injury was assessed by protein levels (B), and ELISA for IL-1β (C), IL-6 (D) and TGF-β (E) in BALF, 5 d after instillation. Bleomycin-induced fibrosis was assessed 21 d after instillation by measuring collagen content in lungs by Sircol assay (F), and by histological examination of lung tissue with H&E staining (G). Original magnification ×40; scale bars, 200 μm. Data in B are means ± SE, C-F are means ± SD from two independent experiments, each with at least three animals per experiment. *P < 0.05, **P < 0.001, ***P<0.0001, by one way ANOVA with a correction provided by the Bonferroni multiple comparisons test.
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Figure 5: Lung injury and fibrosis are attenuated in Vim-/- bone marrow chimeric mice(A) Treatment protocol: CD45.1+ WT mice were lethally irradiated (6 Gy) and two sets of mice were transplanted either with 1×106 CD45.2+ WT or Vim-/- BM cells to generate chimeric mice. 6.5w later, when >90% of AM were of donor (WT and Vim-/-) phenotype, chimeric mice were treated with saline or bleomycin and subjected to analyses. Bleomycin-induced lung injury was assessed by protein levels (B), and ELISA for IL-1β (C), IL-6 (D) and TGF-β (E) in BALF, 5 d after instillation. Bleomycin-induced fibrosis was assessed 21 d after instillation by measuring collagen content in lungs by Sircol assay (F), and by histological examination of lung tissue with H&E staining (G). Original magnification ×40; scale bars, 200 μm. Data in B are means ± SE, C-F are means ± SD from two independent experiments, each with at least three animals per experiment. *P < 0.05, **P < 0.001, ***P<0.0001, by one way ANOVA with a correction provided by the Bonferroni multiple comparisons test.

Mentions: Because multiple cell types contribute to the inflammatory and fibrotic responses, we next addressed the respective roles of bone marrow–derived cells in bleomycin-induced lung injury and fibrosis by generating bone marrow chimeras (Figure 5A). Reconstitution of bone marrow from WT donor mice into irradiated recipient mice (WT) resulted in protein accumulation in BALF in response to bleomycin, whereas in recipient mice reconstituted with bone marrow from Vim-/- donor mice (Vim-/-) the BALF protein was unchanged from saline controls (Figure 5B). Secretion of IL-1β (Figure 5C), IL-6 (Figure 5D), and TGF-β (Figure 5E) in the BALF of WT mice significantly increased in response to bleomycin; the response in Vim-/- mice was significantly attenuated. Finally, WT mice displayed a significant degree of collagen deposition and fibrosis, as shown by Masson trichrome (Figure 5G) and Picrosirius red stain (Supplemental Figure 5C) and Sircol assay (Figure 5F), whereas this response was severely attenuated in Vim-/- mice (Figure 5F, 5G and Supplemental Figure 5C). All together, these results suggest that vimentin-expressing bone marrow–derived cells are important for bleomycin-induced activation of the NLRP3 inflammasome and pulmonary fibrosis.


Vimentin regulates activation of the NLRP3 inflammasome.

dos Santos G, Rogel MR, Baker MA, Troken JR, Urich D, Morales-Nebreda L, Sennello JA, Kutuzov MA, Sitikov A, Davis JM, Lam AP, Cheresh P, Kamp D, Shumaker DK, Budinger GR, Ridge KM - Nat Commun (2015)

Lung injury and fibrosis are attenuated in Vim-/- bone marrow chimeric mice(A) Treatment protocol: CD45.1+ WT mice were lethally irradiated (6 Gy) and two sets of mice were transplanted either with 1×106 CD45.2+ WT or Vim-/- BM cells to generate chimeric mice. 6.5w later, when >90% of AM were of donor (WT and Vim-/-) phenotype, chimeric mice were treated with saline or bleomycin and subjected to analyses. Bleomycin-induced lung injury was assessed by protein levels (B), and ELISA for IL-1β (C), IL-6 (D) and TGF-β (E) in BALF, 5 d after instillation. Bleomycin-induced fibrosis was assessed 21 d after instillation by measuring collagen content in lungs by Sircol assay (F), and by histological examination of lung tissue with H&E staining (G). Original magnification ×40; scale bars, 200 μm. Data in B are means ± SE, C-F are means ± SD from two independent experiments, each with at least three animals per experiment. *P < 0.05, **P < 0.001, ***P<0.0001, by one way ANOVA with a correction provided by the Bonferroni multiple comparisons test.
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Figure 5: Lung injury and fibrosis are attenuated in Vim-/- bone marrow chimeric mice(A) Treatment protocol: CD45.1+ WT mice were lethally irradiated (6 Gy) and two sets of mice were transplanted either with 1×106 CD45.2+ WT or Vim-/- BM cells to generate chimeric mice. 6.5w later, when >90% of AM were of donor (WT and Vim-/-) phenotype, chimeric mice were treated with saline or bleomycin and subjected to analyses. Bleomycin-induced lung injury was assessed by protein levels (B), and ELISA for IL-1β (C), IL-6 (D) and TGF-β (E) in BALF, 5 d after instillation. Bleomycin-induced fibrosis was assessed 21 d after instillation by measuring collagen content in lungs by Sircol assay (F), and by histological examination of lung tissue with H&E staining (G). Original magnification ×40; scale bars, 200 μm. Data in B are means ± SE, C-F are means ± SD from two independent experiments, each with at least three animals per experiment. *P < 0.05, **P < 0.001, ***P<0.0001, by one way ANOVA with a correction provided by the Bonferroni multiple comparisons test.
Mentions: Because multiple cell types contribute to the inflammatory and fibrotic responses, we next addressed the respective roles of bone marrow–derived cells in bleomycin-induced lung injury and fibrosis by generating bone marrow chimeras (Figure 5A). Reconstitution of bone marrow from WT donor mice into irradiated recipient mice (WT) resulted in protein accumulation in BALF in response to bleomycin, whereas in recipient mice reconstituted with bone marrow from Vim-/- donor mice (Vim-/-) the BALF protein was unchanged from saline controls (Figure 5B). Secretion of IL-1β (Figure 5C), IL-6 (Figure 5D), and TGF-β (Figure 5E) in the BALF of WT mice significantly increased in response to bleomycin; the response in Vim-/- mice was significantly attenuated. Finally, WT mice displayed a significant degree of collagen deposition and fibrosis, as shown by Masson trichrome (Figure 5G) and Picrosirius red stain (Supplemental Figure 5C) and Sircol assay (Figure 5F), whereas this response was severely attenuated in Vim-/- mice (Figure 5F, 5G and Supplemental Figure 5C). All together, these results suggest that vimentin-expressing bone marrow–derived cells are important for bleomycin-induced activation of the NLRP3 inflammasome and pulmonary fibrosis.

Bottom Line: Activation of the NLRP3 inflammasome and subsequent maturation of IL-1β have been implicated in acute lung injury (ALI), resulting in inflammation and fibrosis.Furthermore, decreased active caspase-1 and IL-1β levels are observed in vitro in Vim(-/-) and vimentin-knockdown macrophages.This study provides insights into lung inflammation and fibrosis and suggests that vimentin may be a key regulator of the NLRP3 inflammasome.

View Article: PubMed Central - PubMed

Affiliation: Division of Pulmonary and Critical Care Medicine, Northwestern University, Chicago, Illinois 60611, USA.

ABSTRACT
Activation of the NLRP3 inflammasome and subsequent maturation of IL-1β have been implicated in acute lung injury (ALI), resulting in inflammation and fibrosis. We investigated the role of vimentin, a type III intermediate filament, in this process using three well-characterized murine models of ALI known to require NLRP3 inflammasome activation. We demonstrate that central pathophysiologic events in ALI (inflammation, IL-1β levels, endothelial and alveolar epithelial barrier permeability, remodelling and fibrosis) are attenuated in the lungs of Vim(-/-) mice challenged with LPS, bleomycin and asbestos. Bone marrow chimeric mice lacking vimentin have reduced IL-1β levels and attenuated lung injury and fibrosis following bleomycin exposure. Furthermore, decreased active caspase-1 and IL-1β levels are observed in vitro in Vim(-/-) and vimentin-knockdown macrophages. Importantly, we show direct protein-protein interaction between NLRP3 and vimentin. This study provides insights into lung inflammation and fibrosis and suggests that vimentin may be a key regulator of the NLRP3 inflammasome.

Show MeSH
Related in: MedlinePlus