Abstract
Neutrophils are critical for antifungal defense, but the mechanisms that clear hyphae and other pathogens that are too large to be phagocytosed remain unknown. We found that neutrophils sensed microbe size and selectively released neutrophil extracellular traps (NETs) in response to large pathogens, such as Candida albicans hyphae and extracellular aggregates of Mycobacterium bovis, but not in response to small yeast or single bacteria. NETs were fundamental in countering large pathogens in vivo. Phagocytosis via dectin-1 acted as a sensor of microbe size and prevented NET release by downregulating the translocation of neutrophil elastase (NE) to the nucleus. Dectin-1 deficiency led to aberrant NET release and NET-mediated tissue damage during infection. Size-tailored neutrophil responses cleared large microbes and minimized pathology when microbes were small enough to be phagocytosed.
This is a preview of subscription content, access via your institution
Access options
Subscribe to this journal
Receive 12 print issues and online access
£139.00 per year
only £11.58 per issue
Buy this article
- Purchase on SpringerLink
- Instant access to full article PDF
Prices may be subject to local taxes which are calculated during checkout
Similar content being viewed by others
References
Scianimanico, S. et al. Impaired recruitment of the small GTPase rab7 correlates with the inhibition of phagosome maturation by Leishmania donovani promastigotes. Cell. Microbiol. 1, 19–32 (1999).
Gantner, B.N., Simmons, R.M. & Underhill, D.M. Dectin-1 mediates macrophage recognition of Candida albicans yeast but not filaments. EMBO J. 24, 1277–1286 (2005).
Goodridge, H.S. et al. Activation of the innate immune receptor Dectin-1 upon formation of a 'phagocytic synapse'. Nature 472, 471–475 (2011).
Gow, N.A., van de Veerdonk, F.L., Brown, A.J. & Netea, M.G. Candida albicans morphogenesis and host defence: discriminating invasion from colonization. Nat. Rev. Microbiol. 10, 112–122 (2012).
Joly, S. et al. Cutting edge: Candida albicans hyphae formation triggers activation of the Nlrp3 inflammasome. J. Immunol. 183, 3578–3581 (2009).
Arendrup, M.C. Epidemiology of invasive candidiasis. Curr. Opin. Crit. Care 16, 445–452 (2010).
Low, C.Y. & Rotstein, C. Emerging fungal infections in immunocompromised patients. F1000 Med. Rep. 3, 14 (2011).
Urban, C.F. et al. Neutrophil extracellular traps contain calprotectin, a cytosolic protein complex involved in host defense against Candida albicans. PLoS Pathog. 5, e1000639 (2009).
Borregaard, N. Neutrophils, from marrow to microbes. Immunity 33, 657–670 (2010).
Amulic, B., Cazalet, C., Hayes, G.L., Metzler, K.D. & Zychlinsky, A. Neutrophil function: from mechanisms to disease. Annu. Rev. Immunol. 30, 459–489 (2012).
Brinkmann, V. et al. Neutrophil extracellular traps kill bacteria. Science 303, 1532–1535 (2004).
Metzler, K.D. et al. Myeloperoxidase is required for neutrophil extracellular trap formation: implications for innate immunity. Blood 117, 953–959 (2011).
Fuchs, T.A. et al. Novel cell death program leads to neutrophil extracellular traps. J. Cell Biol. 176, 231–241 (2007).
Papayannopoulos, V., Metzler, K.D., Hakkim, A. & Zychlinsky, A. Neutrophil elastase and myeloperoxidase regulate the formation of neutrophil extracellular traps. J. Cell Biol. 191, 677–691 (2010).
Metzler, K.D., Goosmann, C., Lubojemska, A., Zychlinsky, A. & Papayannopoulos, V. A myeloperoxidase-containing complex regulates neutrophil elastase release and actin dynamics during NETosis. Cell Reports 8, 883–896 (2014).
Bianchi, M. et al. Restoration of NET formation by gene therapy in CGD controls aspergillosis. Blood 114, 2619–2622 (2009).
Lehrer, R.I. & Cline, M.J. Leukocyte myeloperoxidase deficiency and disseminated candidiasis - role of myeloperoxidase in resistance to Candida infection. J. Clin. Invest. 48, 1478–1488 (1969).
Parry, M.F. et al. Myeloperoxidase deficiency - prevalence and clinical significance. Ann. Intern. Med. 95, 293–301 (1981).
Branzk, N. & Papayannopoulos, V. Molecular mechanisms regulating NETosis in infection and disease. Semin. Immunopathol. 35, 513–530 (2013).
Caza, T., Oaks, Z. & Perl, A. Interplay of infections, autoimmunity, and immunosuppression in systemic lupus erythematosus. Int. Rev. Immunol. 33, 330–363 (2014).
Zheng, X., Wang, Y. & Wang, Y. Hgc1, a novel hypha-specific G1 cyclin-related protein regulates Candida albicans hyphal morphogenesis. EMBO J. 23, 1845–1856 (2004).
Martínez-Gomariz, M. et al. Proteomic analysis of cytoplasmic and surface proteins from yeast cells, hyphae, and biofilms of Candida albicans. Proteomics 9, 2230–2252 (2009).
Martchenko, M., Alarco, A.M., Harcus, D. & Whiteway, M. Superoxide dismutases in Candida albicans: transcriptional regulation and functional characterization of the hyphal-induced SOD5 gene. Mol. Biol. Cell 15, 456–467 (2004).
Grinberg, N., Elazar, S., Rosenshine, I. & Shpigel, N.Y. β-hydroxybutyrate abrogates formation of bovine neutrophil extracellular traps and bactericidal activity against mammary pathogenic Escherichia coli. Infect. Immun. 76, 2802–2807 (2008).
Mori, Y. et al. α-Enolase of Streptococcus pneumoniae induces formation of neutrophil extracellular traps. J. Biol. Chem. 287, 10472–10481 (2012).
Domenech, M., Ramos-Sevillano, E., Garcia, E., Moscoso, M. & Yuste, J. Biofilm formation avoids complement immunity and phagocytosis of Streptococcus pneumoniae. Infect. Immun. 81, 2606–2615 (2013).
Walker, J.N. et al. The Staphylococcus aureus ArlRS two-component system is a novel regulator of agglutination and pathogenesis. PLoS Pathog. 9, e1003819 (2013).
McAdow, M. et al. Preventing Staphylococcus aureus sepsis through the inhibition of its agglutination in blood. PLoS Pathog. 7, e1002307 (2011).
Bernut, A. et al. Mycobacterium abscessus cording prevents phagocytosis and promotes abscess formation. Proc. Natl. Acad. Sci. USA 111, E943–E952 (2014).
Hakkim, A. et al. Activation of the Raf-MEK-ERK pathway is required for neutrophil extracellular trap formation. Nat. Chem. Biol. 7, 75–77 (2011).
Drummond, R.A., Saijo, S., Iwakura, Y. & Brown, G.D. The role of Syk/CARD9 coupled C-type lectins in antifungal immunity. Eur. J. Immunol. 41, 276–281 (2011).
Nordenfelt, P. & Tapper, H. Phagosome dynamics during phagocytosis by neutrophils. J. Leukoc. Biol. 90, 271–284 (2011).
Mollinedo, F. et al. Combinatorial SNARE complexes modulate the secretion of cytoplasmic granules in human neutrophils. J. Immunol. 177, 2831–2841 (2006).
Herre, J. et al. Dectin-1 uses novel mechanisms for yeast phagocytosis in macrophages. Blood 104, 4038–4045 (2004).
Kennedy, A.D. et al. Dectin-1 promotes fungicidal activity of human neutrophils. Eur. J. Immunol. 37, 467–478 (2007).
Watson, R.W., Redmond, H.P., Wang, J.H., Condron, C. & Bouchier-Hayes, D. Neutrophils undergo apoptosis following ingestion of Escherichia coli. J. Immunol. 156, 3986–3992 (1996).
Garcia-Romo, G.S. et al. Netting neutrophils are major inducers of type I IFN production in pediatric systemic lupus erythematosus. Sci. Transl. Med. 3, 73ra20 (2011).
Kaplan, M.J. Role of neutrophils in systemic autoimmune diseases. Arthritis Res. Ther. 15, 219 (2013).
Villanueva, E. et al. Netting neutrophils induce endothelial damage, infiltrate tissues, and expose immunostimulatory molecules in systemic lupus erythematosus. J. Immunol. 187, 538–552 (2011).
Gupta, A.K. et al. Activated endothelial cells induce neutrophil extracellular traps and are susceptible to NETosis-mediated cell death. FEBS Lett. 584, 3193–3197 (2010).
Carmona-Rivera, C., Zhao, W., Yalavarthi, S. & Kaplan, M.J. Neutrophil extracellular traps induce endothelial dysfunction in systemic lupus erythematosus through the activation of matrix metalloproteinase-2. Ann. Rheum. Dis. doi:10.1136/annrheumdis-2013-204837 (25 February 2014)10.1136/annrheumdis-2013-204837.
Taylor, P.R. et al. Dectin-1 is required for β-glucan recognition and control of fungal infection. Nat. Immunol. 8, 31–38 (2007).
Robinson, M.J. et al. Dectin-2 is a Syk-coupled pattern recognition receptor crucial for Th17 responses to fungal infection. J. Exp. Med. 206, 2037–2051 (2009).
Fujie, K. et al. Release of neutrophil elastase and its role in tissue injury in acute inflammation: effect of the elastase inhibitor, FR134043. Eur. J. Pharmacol. 374, 117–125 (1999).
Ishii, T. et al. Neutrophil elastase contributes to acute lung injury induced by bilateral nephrectomy. Am. J. Pathol. 177, 1665–1673 (2010).
Kawabata, K., Hagio, T. & Matsuoka, S. The role of neutrophil elastase in acute lung injury. Eur. J. Pharmacol. 451, 1–10 (2002).
Prashar, A. et al. Filamentous morphology of bacteria delays the timing of phagosome morphogenesis in macrophages. J. Cell Biol. 203, 1081–1097 (2013).
Kusner, D.J. Mechanisms of mycobacterial persistence in tuberculosis. Clin. Immunol. 114, 239–247 (2005).
Deretic, V. Autophagy, an immunologic magic bullet: Mycobacterium tuberculosis phagosome maturation block and how to bypass it. Future Microbiol. 3, 517–524 (2008).
Simeone, R. et al. Phagosomal rupture by Mycobacterium tuberculosis results in toxicity and host cell death. PLoS Pathog. 8, e1002507 (2012).
Wong, K.W. & Jacobs, W.R. Jr. Mycobacterium tuberculosis exploits human interferon γ to stimulate macrophage extracellular trap formation and necrosis. J. Infect. Dis. 208, 109–119 (2013).
Saitoh, T. et al. Neutrophil extracellular traps mediate a host defense response to human immunodeficiency virus-1. Cell Host Microbe 12, 109–116 (2012).
Fossati-Jimack, L. et al. Phagocytosis is the main CR3-mediated function affected by the lupus-associated variant of CD11b in human myeloid cells. PLoS ONE 8, e57082 (2013).
Salazar-Aldrete, C. et al. Expression and function of dectin-1 is defective in monocytes from patients with systemic lupus erythematosus and rheumatoid arthritis. J. Clin. Immunol. 33, 368–377 (2013).
Aga, E. et al. Inhibition of the spontaneous apoptosis of neutrophil granulocytes by the intracellular parasite Leishmania major. J. Immunol. 169, 898–905 (2002).
Kasmapour, B., Gronow, A., Bleck, C.K., Hong, W. & Gutierrez, M.G. Size-dependent mechanism of cargo sorting during lysosome-phagosome fusion is controlled by Rab34. Proc. Natl. Acad. Sci. USA 109, 20485–20490 (2012).
Benghezal, M. et al. Inhibitors of bacterial virulence identified in a surrogate host model. Cell. Microbiol. 9, 1336–1342 (2007).
Acknowledgements
We thank the blood donors; Y. Wang (Institute of Molecular and Cell Biology of the Agency for Science, Technology and Research) and N. Gow (University of Aberdeen) for the hgc1Δ C. albicans strain; G. Stockinger, M. Wilson and A. Zychlinsky for comments on the manuscript; E. Bernard for help with the M. bovis preparation; D. Bell for advice on microscopy; and A. Adekoya and K. Mathers for support with animal experiments. Supported by the Medical Research Council (UK) (MC_UP_1202/13 for V.P., and MC_UP_1202/11 for M.G.G.) and the Wellcome Trust.
Author information
Authors and Affiliations
Contributions
N.B. performed all experiments, except as noted below; S.E.H. and G.D.B. infected mice with A. fumigatus; N.B., A.L., Q.W. and V.P. did immunoblot analysis and neutrophil immunofluorescence microscopy; M.G.G. provided advice for and contributed to the M. bovis BCG experiments; V.P. devised and directed the study; and N.B. and V.P. wrote the manuscript.
Corresponding author
Ethics declarations
Competing interests
The authors declare no competing financial interests.
Integrated supplementary information
Supplementary Figure 1 Hyphae induce NET release, but yeast do not.
(a) NET release by human peripheral neutrophils stimulated with a hgc1Δ yeast-locked C. albicans mutant (yeast) or pre-formed WT C. albicans hyphae with or without plasma. MOI = 10. Scale bars = 50 μm. (b) Quantification of NET release of human peripheral neutrophils stimulated with preformed WT C. albicans hyphae or hgc1Δ yeast-locked C. albicans with 3% plasma. Percentage (%) of Sytox positive events over total number of neutrophils. Statistics by one-way ANOVA, followed by Tukey’s multiple comparison post test: * p<0.0001. (c) NET release by human peripheral neutrophils stimulated with heat-killed C. albicans hyphae..(d) Quantification of NET release by neutrophils stimulated with heat inactivated or untreated C. albicans hyphae. Percentage (%) of Sytox positive events over total number of neutrophils. Statistics by one-way ANOVA, followed by Tukey’s multiple comparison post test: * p<0.0001. (e) Peripheral human neutrophils attached to the bottom of a modified transwell membrane 1 h post incubation and after removal followed by 3 rinses with PBS. Nuclei stained with DAPI (blue). (f) Quantification of NET release after direct stimulation of human peripheral neutrophils with C. albicans hgc1Δ yeast, separated by a suspended transwell that does not allow direct contact but exchange of soluble factors. Percentage (%) of Sytox positive events over total number of neutrophils. Scale bars (a, c) 50 μm. Statistics by one-way ANOVA, followed by Tukey’s multiple comparison post test: NS p>0.5, * p<0.0001. Data are representative of at least three independent experiments. US; unstimulated.
Supplementary Figure 2 Small hyphae fragments fail to induce NET release.
(a, b) Confocal microscopy 0.8 μm z-stack series (z:1 to z:6 or z:9) of human peripheral neutrophils stimulated with (a) fragmented heat-killed C. albicans hyphae (MOI = equivalent of 10 intact hyphae) or (b) intact heat-killed C. albicans hyphae (MOI = 10). Fixed 60 min post stimulation. Stained for MPO (green), C. albicans (red) and DNA (DAPI, blue). (b) depicts a neutrophil that has just released NETs. Scale bars (a, b), 5 μm. Data are representative of at least three independent experiments.
Supplementary Figure 3 A. fumigatus filaments and aggregates induce NETs.
Human peripheral neutrophils stimulated with A. fumigatus with or without 3% plasma. Hyphae were preformed in RPMI medium. Aggregates form in presence of plasma. DNA (Sytox) stain of NET release 4 h post stimulation. Scale bars, 50 μm. Data are representative of at least three independent experiments.
Supplementary Figure 4 NADPH oxidase–deficient mice are susceptible to hgc1Δ yeast-locked C. albicans.
(a) Weight of WT (C57BL/6) and NADPH oxidase KO mice after infection with 1x104 c.f.u. of hgc1Δ yeast locked C. albicans (n=5) and WT C. albicans (n=5). Weight normalized to starting weight at d0. Statistics by two-way ANOVA, followed by Sidak’s multiple comparison post test: NS p>0.5, * p<0.0001. Data are representative of two independent experiments. b) Overview of antimicrobial strategies of WT (C57BL/6), dectin-1 deficient and NADPH oxidase deficient mice after stimulation with WT or yeast locked C. albicans. (error bars (b), s.d.)
Supplementary Figure 5 Yeast and hyphae induce similar signaling.
(a) Syk and ERK kinase activation in human peripheral neutrophils stimulated with WT C. albicans hyphae or hgc1Δ yeast-locked mutant C. albicans for the indicated times and assessed by immunoblotting. (b) Production of reactive oxygen species (ROS) by human peripheral neutrophils after stimulation with WT C. albicans hyphae or hgc1Δ yeast-locked mutant C. albicans. Data are representative of at least three independent experiments. US, unstimulated; LU, luminescence units.
Supplementary Figure 6 Increased NET release and tissue damage in the lungs of dectin-1-deficient mice.
(a) NET release in lungs of WT (C57BL/6) and dectin-1 deficient mice infected with 1x105 c.f.u. WT C. albicans 24 hours post infection stained for DNA (DAPI), MPO and citrullinated histone H3 (H3-cit) and analyzed by immunofluorescence confocal microscopy. Scale bars, 20 μm. (b) C. albicans load in the lung 12 h post infection (n=3). Statistics by unpaired t test: NS p>0.05 (c) Overview of neutrophil infiltration. Lungs of WT (C57BL/6) and dectin-1 deficient mice infected with of 3x106 c.f.u. hgc1Δ yeast-locked C. albicans. Fixation and staining of lung sections with hematoxylin and eosin (HE) 36 hours post infection. Scale bars, 1 mm. (d) TNFα levels in lung sections of WT (C57BL/6) and dectin-1 deficient mice infected with of 3x106 c.f.u. hgc1Δ yeast-locked C. albicans 36 h post infection, stained by immunohistochemistry with an antibody against TNFα (brown) and hematoxylin (DNA, blue). Scale bars, 50 μm. Data are representative of two independent experiments. UT, untreated.
Supplementary Figure 7 Increased NET-mediated tissue damage in dectin-1-deficient mice.
(a) Lungs of WT (C57BL/6) and dectin-1 deficient mice infected with of 3x106 c.f.u. hgc1Δ yeast-locked C. albicans. Fixation and staining of lung sections with hematoxylin and eosin (HE) 36 hours post infection. Tissue damage manifested in fibrin deposition and bleeding. Arrows indicate fibrin deposition and bleeding. Bottom panels depict higher magnification of areas indicated by black dotted squares. Data are representative of two independent experiments. UT, untreated. Lower panel: magnification detail in upper panel. (b) Overview of causes of pathology in WT (C57BL/6) and dectin-1-deficient mice after infection with hgc1Δ yeast-locked C. albicans. (c) Phagocytosed yeast particles drive the translocation of NE to the phagosome via fusion with azurophilic granules, sequestering NE away from the nucleus. In contrast, in the absence of a phagosome during the response to hyphae, NE translocates from azurophilic granules to the nucleus, processing histones to drive chromatin decondensation. By inhibiting NETosis, phagocytosis prevents tissue damage caused by uncontrolled NET release. Scale bars (a) 50 μm
Supplementary information
Supplementary Text and Figures
Supplementary Figures 1–7 (PDF 7247 kb)
Yeast-locked C. albicans fails to induce NET release in human peripheral neutrophils.
Time-lapse microscopy of live human peripheral neutrophils stimulated with hgc1Δ yeast-locked C. albicans. Confocal images were taken every 30 seconds. The movie represents 9 frames/second. Red: Reactive oxygen species (NBT), Green: DNA (Sytox). (MP4 30051 kb)
Yeast-locked C. albicans induces NET release in dectin-1 blocked human peripheral neutrophils.
Time-lapse microscopy of live human peripheral neutrophils stimulated with hgc1Δ yeast-locked C. albicans in presence of anti-dectin-1 blocking antibody. Confocal images were taken every 30 seconds. The movie represents 9 frames/second. Red: Reactive oxygen species (NBT), Green: DNA (Sytox). (MP4 32445 kb)
Rights and permissions
About this article
Cite this article
Branzk, N., Lubojemska, A., Hardison, S. et al. Neutrophils sense microbe size and selectively release neutrophil extracellular traps in response to large pathogens. Nat Immunol 15, 1017–1025 (2014). https://doi.org/10.1038/ni.2987
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1038/ni.2987
This article is cited by
-
Neutrophils and neutrophil extracellular traps in oral health and disease
Experimental & Molecular Medicine (2024)
-
Activation of leukotriene B4 receptor 1 is a prerequisite for complement receptor 3-mediated antifungal responses of neutrophils
Cellular & Molecular Immunology (2024)
-
Fasciola hepatica soluble antigens (FhAg) induce ovine PMN innate immune reactions and NET formation in vitro and in vivo
Veterinary Research (2023)
-
Evaluation of the innate immune response of caprine neutrophils against Mycobacterium avium subspecies paratuberculosis in vitro
Veterinary Research (2023)
-
Schistosome egg-derived extracellular vesicles deliver Sja-miR-71a inhibits host macrophage and neutrophil extracellular traps via targeting Sema4D
Cell Communication and Signaling (2023)