Contemporary understanding of the secretory granules in human eosinophils

Melo, Rossana C. N.; Weller, Peter F.

doi:10.1002/jlb.3mr1217-476r

Cited by 78 publications

(68 citation statements)

References 77 publications

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“…Release of mediators from granules of live eosinophils occurs by exocytosis or piecemeal release and was measured in IL3‐primed eosinophils on IgG using EDN release into the extracellular compartment. Contrasting with release of intact granules by cytolysis, eosinophil release of granule proteins was detected soon after adhesion (30 minutes, P = .005 compared with no IgG at 6 hours) and continued linearly up to 6 hours (Figure A), indicating decoupling of degranulation and cytolysis.…”

Section: Resultsmentioning

confidence: 99%

Eosinophil cytolysis on Immunoglobulin G is associated with microtubule formation and suppression of rho‐associated protein kinase signalling

Esnault

Leet

Johansson

et al. 2019

Clin Experimental Allergy

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Esnault and Leet have participated equally to the work.Abbreviations: CD32, receptor for Fc fragment of IgG, low affinity II (FCGRII); DAPI, 4′,6-diamidino-2-phenylindole; DPI, diphenyleneiodonium; EDN, eosinophil-derived neurotoxin;HA-IgG, heat-aggregated immunoglobulin G; MAP4, microtubule-associated protein 4; MAPK, mitogen-activated protein kinase; MT, microtubule; NADPH, dihydronicotinamide-adenine dinucleotide phosphate; PFA, paraformaldehyde; PI3K, phosphatidylinositol 3'-kinase; ROCK, Rho-associated, coiled-coil containing protein kinase; ROS, reactive oxygen species; SBP-Ag, segmental bronchoprovocation with an allergen. AbstractBackground: The presence of eosinophils in the airway is associated with asthma severity and risk of exacerbations. Cell-free eosinophil granules are found in tissues in eosinophilic diseases, including asthma. This suggests that eosinophils have lysed and released cellular content, likely harming tissues.Objective: The present study explores the mechanism of CD32-and αMß2 integrindependent eosinophil cytolysis of IL3-primed blood eosinophils seeded on heat-aggregated immunoglobulin G (HA-IgG). Methods: Cytoskeletal events and signalling pathways potentially involved in cytolysiswere assessed using inhibitors. The level of activation of the identified events and pathways involved in cytolysis was measured. In addition, the links between these identified pathways and changes in degranulation (exocytosis) and adhesion were analysed.Results: Cytolysis of IL3-primed eosinophils was dependent on the production of reactive oxygen species (ROS) and downstream phosphorylation of p-38 MAPK. In addition, formation of microtubule (MT) arrays was necessary for cytolysis and was accompanied by changes in MT dynamics as measured by phosphorylation status of stathmin and microtubule-associated protein 4 (MAP4), the latter of which was regulated by ROS production. Reduced ROCK signalling preceded cytolysis, which was associated with eosinophil adhesion and reduced migration. Conclusion and Clinical Relevance:In this CD32-and αMß2 integrin-dependent adhesion model, lysing eosinophils exhibit reduced migration and ROCK signalling, as well as both MT dynamic changes and p-38 phosphorylation downstream of ROS production. We propose that interfering with these pathways would modulate eosinophil cytolysis and subsequent eosinophil-driven tissue damage. K E Y W O R D Sadhesion, cytolysis, degranulation, Eosinophil, IL3, immunoglobulin G, microtubule, priming | 199 STEPHANE ET Al.

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Section: Resultsmentioning

confidence: 99%

Eosinophil cytolysis on Immunoglobulin G is associated with microtubule formation and suppression of rho‐associated protein kinase signalling

Esnault

Leet

Johansson

et al. 2019

Clin Experimental Allergy

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“…Skin eosinophilia can be seen in several dermatoses including bullous pemphigoid (BP), where a cutaneous deposition of eosinophil degranulation proteins is a major feature . Eosinophil degranulation proteins include major basic protein (MBP), eosinophil peroxidase (EPO), CLC/Gal‐10 and the two ribonucleases (RNAses): eosinophil cationic protein (ECP) and eosinophil‐derived neurotoxin (EDN) …”

Section: Introductionmentioning

confidence: 99%

Mechanisms of pathogenic effects of eosinophil cationic protein and eosinophil‐derived neurotoxin on human keratinocytes

Amber

Chernyavsky

Agnoletti

et al. 2018

Experimental Dermatology

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Cutaneous deposition of eosinophil degranulation proteins is a major feature of eosinophil-rich cutaneous diseases including bullous pemphigoid (BP). We sought to better understand the effect of two of these proteins - eosinophil cationic protein (ECP) and eosinophil-derived neurotoxin (EDN), on human keratinocytes using the Het-1A cell line. To evaluate expression of key cytokines and chemokines observed in BP as well as metal metalloprotease 9 (MMP9), we performed qPCR and in-cell Western assays on cells treated with either ECP or EDN. We further evaluated the effect of ECP and EDN on keratinocyte survival, generation of reactive oxygen species (ROS) and apoptosis. Lastly, we assessed ECP and EDN's ability to induce keratinocyte detachment from provisional matrix. Treatment of keratinocytes with ECP and EDN resulted in significant increases in IL-5, eotaxin-1 and CCL5 (RANTES) expression at both mRNA and protein levels, but not IL-17 or IL-31. ECP and EDN also upregulate MMP9 production. Inhibiting MMP9, we confirmed that keratinocyte expression of IL-5, eotaxin-1 and RANTES was independent from MMP9. Both ECP and EDN were cytotoxic to keratinocytes, inducing ROS formation and apoptosis through a mitochondrion-dependent pathway as evidenced by results of terminal deoxynucleotidyl transferase dUTP nick-end labelling (TUNEL) and cytochrome c release assays, respectively. ECP but not EDN led to significant keratinocyte detachment from provisional matrix. These findings demonstrate that the pathogenic effects of ECP and EDN in BP may result from their direct action on keratinocytes, and as such may became a target for future therapies in eosinophil-rich cutaneous diseases.

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“…Integration of signals from the microenvironment preferentially activates different secretory pathways within eosinophils; discrete activation profiles measurable by image analysis of peripheral blood eosinophils could therefore provide insight into disease phenotype or endotype and response to treatment. Allergic disease, asthma, and parasite infection have been the focus for eosinophil‐related research these past decades, but there is growing appreciation of their contribution to host defense against bacteria and viruses, various hypereosinophilic syndromes, autoimmune disease, cancer, and a range of eosinophilic gastrointestinal disorders that are increasing in prevalence .…”

Section: Discussionmentioning

confidence: 99%

Diffusion Mapping of Eosinophil‐Activation State

et al. 2019

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Eosinophils are granular leukocytes that play a role in mediating inflammatory responses linked to infection and allergic disease. Their activation during an immune response triggers spatial reorganization and eventual cargo release from intracellular granules. Understanding this process is important in diagnosing eosinophilic disorders and in assessing treatment efficacy; however, current protocols are limited to simply quantifying the number of eosinophils within a blood sample. Given that high optical absorption and scattering by the granular structure of these cells lead to marked image features, the physical changes that occur during activation should be trackable using image analysis. Here, we present a study in which imaging flow cytometry is used to quantify eosinophil activation state, based on the extraction of 85 distinct spatial features from dark‐field images formed by light scattered orthogonally to the illuminating beam. We apply diffusion mapping, a time inference method that orders cells on a trajectory based on similar image features. Analysis of exogenous cell activation using eotaxin and endogenous activation in donor samples with elevated eosinophil counts shows that cell position along the diffusion‐path line correlates with activation level (99% confidence level). Thus, the diffusion mapping provides an activation metric for each cell. Assessment of activated and control populations using both this spatial image‐based, activation score and the integrated side‐scatter intensity shows an improved Fisher discriminant ratio rd = 0.7 for the multivariate technique compared with an rd = 0.47 for the traditional whole‐cell scatter metric. © 2019 The Authors. Cytometry Part A published by Wiley Periodicals, Inc. on behalf of International Society for Advancement of Cytometry.

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Contemporary understanding of the secretory granules in human eosinophils

Cited by 78 publications

References 77 publications

Eosinophil cytolysis on Immunoglobulin G is associated with microtubule formation and suppression of rho‐associated protein kinase signalling

Eosinophil cytolysis on Immunoglobulin G is associated with microtubule formation and suppression of rho‐associated protein kinase signalling

Mechanisms of pathogenic effects of eosinophil cationic protein and eosinophil‐derived neurotoxin on human keratinocytes

Diffusion Mapping of Eosinophil‐Activation State

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