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Weihrauch T, Melo RCN, Gray N, Voehringer D, Weller PF, Raap U. Eosinophil extracellular vesicles and DNA traps in allergic inflammation. FRONTIERS IN ALLERGY 2024; 5:1448007. [PMID: 39148911 PMCID: PMC11324581 DOI: 10.3389/falgy.2024.1448007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2024] [Accepted: 07/23/2024] [Indexed: 08/17/2024] Open
Abstract
Eosinophil granulocytes, a specialized subset of white blood cells, have traditionally been associated with allergic responses and parasitic infections. However, recent research has unveiled their versatile roles in immune regulation beyond these classical functions. This review highlights the emerging field of eosinophil biology, with a particular focus on their release of extracellular vesicles (EVs) and extracellular DNA traps (EETs). It further explores potential implications of eosinophil-derived EVs and EETs for immune responses during inflammatory diseases. The release of EVs/EETs from eosinophils, which also affects the eosinophils themselves, may influence both local and systemic immune reactions, affecting the pathophysiology of conditions such as airway inflammation, chronic rhinosinusitis and atopic dermatitis.
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Affiliation(s)
- Tobias Weihrauch
- Division of Experimental Allergy and Immunodermatology, Faculty of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Rossana C N Melo
- Laboratory of Cellular Biology, Department of Biology, Institute of Biological Sciences (ICB), Federal University of Juiz de Fora, UFJF, Juiz de Fora, Brazil
| | - Natalie Gray
- Division of Experimental Allergy and Immunodermatology, Faculty of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
- Division of Anatomy, Faculty of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| | - David Voehringer
- Department of Infection Biology, University Hospital Erlangen, Erlangen, Germany
- FAU Profile Center Immunomedicine (FAU I-MED), Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Peter F Weller
- Division of Allergy and Inflammation, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, United States
| | - Ulrike Raap
- Division of Experimental Allergy and Immunodermatology, Faculty of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
- Research Center for Neurosensory Science, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
- University Clinic of Dermatology and Allergy, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
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Almas S, Fayad N, Srivastava O, Siddique M, Das S, Touret N, Sun X, Lacy P. Immunofluorescence analysis of human eosinophils. J Immunol Methods 2024; 526:113619. [PMID: 38272178 DOI: 10.1016/j.jim.2024.113619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 01/13/2024] [Accepted: 01/15/2024] [Indexed: 01/27/2024]
Abstract
A prominent inflammatory cell type in allergic diseases is the eosinophil, a granulated white blood cell that releases pro-inflammatory cytokines. Eosinophil-derived cytokines, including interleukin-9 (IL-9) and interleukin-13 (IL-13), can skew the immune response towards an allergic phenotype. Unfortunately, it is challenging to immunolabel and collect quantifiable images of eosinophils given their innate autofluorescence and ability to nonspecifically bind to antibodies. Hence, it is important to optimize permeabilization, blocking, and imaging conditions for eosinophils. Here, we show enhanced protocols to ensure that measured immunofluorescence represents specific immunolabelling. To test this, eosinophils were purified from human blood, adhered to glass coverslips, stimulated with or without platelet-activating factor (PAF), fixed with paraformaldehyde, and then permeabilized with Triton X-100 or saponin. Cells were then blocked with goat serum or human serum and incubated with antibodies labelling cytokines (IL-9 and IL-13) and secretory organelles (CD63 for crystalloid granules and transferrin receptor [TfnRc] for recycling endosomes). Carefully selected isotype controls were used throughout, and cells were imaged using Deltavision super-resolution microscopy. Intensities of fluorescent probes were quantified using Volocity software. Our findings show that permeabilization with saponin, blockage with human serum, and using concentrations of antibodies up to 10 μg/ml allowed us to detect marked differences in fluorescence intensities between isotypes and test antibodies. With the achievement of sufficient qualitative and quantitative measures of increased test probe intensity compared to respective isotypes, these results indicate that our protocol allows for optimal immunolabelling of eosinophils. Using this protocol, future studies may provide further insights into trafficking mechanisms within this important inflammatory cell type.
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Affiliation(s)
- Sarah Almas
- Alberta Respiratory Centre (ARC) Research, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada.
| | - Nawell Fayad
- Alberta Respiratory Centre (ARC) Research, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Ojas Srivastava
- Alberta Respiratory Centre (ARC) Research, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Mujtaba Siddique
- Alberta Respiratory Centre (ARC) Research, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Sharanya Das
- Alberta Respiratory Centre (ARC) Research, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Nicolas Touret
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Xuejun Sun
- Department of Oncology, University of Alberta, Edmonton, Alberta, Canada
| | - Paige Lacy
- Alberta Respiratory Centre (ARC) Research, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
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Therapeutic Effect of Renifolin F on Airway Allergy in an Ovalbumin-Induced Asthma Mouse Model In Vivo. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27123789. [PMID: 35744915 PMCID: PMC9227769 DOI: 10.3390/molecules27123789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 06/08/2022] [Accepted: 06/11/2022] [Indexed: 11/23/2022]
Abstract
Renifolin F is a prenylated chalcone isolated from Shuteria involucrata, a traditional minority ethnic medicine used to treat the respiratory diseases and asthma. Based on the effects of the original medicine plant, we established an in vivo mouse model of allergic asthma using ovalbumin (OVA) as an inducer to evaluate the therapeutic effects of Renifolin F. In the research, mice were sensitized and challenged with OVA to establish an allergic asthma model to evaluate the effects of Renifolin F on allergic asthma. The airway hyper-reactivity (AHR) to methacholine, cytokine levels, ILC2s quantity and mircoRNA-155 expression were assessed. We discovered that Renifolin F attenuated AHR and airway inflammation in the OVA-induced asthmatic mouse model by inhibiting the regulation of ILC2s in the lung, thereby, reducing the upstream inflammatory cytokines IL-25, IL-33 and TSLP; the downstream inflammatory cytokines IL-4, IL-5, IL-9 and IL-13 of ILC2s; and the co-stimulatory factors IL-2 and IL-7; as well as the expression of microRNA-155 in the lung. The findings suggest a therapeutic potential of Renifolin F on OVA-induced airway inflammation.
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Fettrelet T, Gigon L, Karaulov A, Yousefi S, Simon HU. The Enigma of Eosinophil Degranulation. Int J Mol Sci 2021; 22:ijms22137091. [PMID: 34209362 PMCID: PMC8268949 DOI: 10.3390/ijms22137091] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 06/23/2021] [Accepted: 06/29/2021] [Indexed: 12/18/2022] Open
Abstract
Eosinophils are specialized white blood cells, which are involved in the pathology of diverse allergic and nonallergic inflammatory diseases. Eosinophils are traditionally known as cytotoxic effector cells but have been suggested to additionally play a role in immunomodulation and maintenance of homeostasis. The exact role of these granule-containing leukocytes in health and diseases is still a matter of debate. Degranulation is one of the key effector functions of eosinophils in response to diverse stimuli. The different degranulation patterns occurring in eosinophils (piecemeal degranulation, exocytosis and cytolysis) have been extensively studied in the last few years. However, the exact mechanism of the diverse degranulation types remains unknown and is still under investigation. In this review, we focus on recent findings and highlight the diversity of stimulation and methods used to evaluate eosinophil degranulation.
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Affiliation(s)
- Timothée Fettrelet
- Institute of Pharmacology, University of Bern, Inselspital, INO-F, CH-3010 Bern, Switzerland; (T.F.); (L.G.); (S.Y.)
- Department of Biochemistry, University of Lausanne, CH-1066 Epalinges, Switzerland
| | - Lea Gigon
- Institute of Pharmacology, University of Bern, Inselspital, INO-F, CH-3010 Bern, Switzerland; (T.F.); (L.G.); (S.Y.)
| | - Alexander Karaulov
- Department of Clinical Immunology and Allergology, Sechenov University, 119991 Moscow, Russia;
| | - Shida Yousefi
- Institute of Pharmacology, University of Bern, Inselspital, INO-F, CH-3010 Bern, Switzerland; (T.F.); (L.G.); (S.Y.)
| | - Hans-Uwe Simon
- Institute of Pharmacology, University of Bern, Inselspital, INO-F, CH-3010 Bern, Switzerland; (T.F.); (L.G.); (S.Y.)
- Department of Clinical Immunology and Allergology, Sechenov University, 119991 Moscow, Russia;
- Laboratory of Molecular Immunology, Institute of Fundamental Medicine and Biology, Kazan Federal University, 420012 Kazan, Russia
- Institute of Biochemistry, Medical School Brandenburg, D-16816 Neuruppin, Germany
- Correspondence: ; Tel.: +41-31-632-3281
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