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Updated: Nov 14, 2025
Isolation and Characterization of Neutrophil-derived Microparticles for Functional Studies
Published on: March 2, 2018
Neutrophil-derived extracellular vesicles modulate the phenotype of naïve human neutrophils
Maya F Amjadi1, Benjamin S Avner1,2, Mallary C Greenlee-Wacker3
1Inflammation Program, Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine University of Iowa, Iowa City, Iowa, USA.
Abstract:
Neutrophils (PMN) regulate inflammation in many ways, including communication with other immune cells via extracellular vesicles (EVs). EVs released by human neutrophils activated with N-formylmethionyl-leucyl-phenylalanine (fMLF) (PMN-fMLF EVs) had an outside-out orientation and contained functionally important neutrophil plasma membrane proteins, including flavocytochrome b558, and enzymatically active granule proteins, elastase, and myeloperoxidase. Treatment of naïve PMN with PMN-fMLF EVs primed fMLF-stimulated NADPH oxidase activity, increased surface expression of the complement receptors CD11b/CD18 and CD35, the specific granule membrane protein CD66, and flavocytochrome b558 , and promoted phagocytosis of serum-opsonized Staphylococcus aureus. The primed oxidase activity reflected increased surface expression of flavocytochrome b558 and phosphorylation of SER345 in p47phox , two recognized mechanisms for oxidase priming. Taken together, these data demonstrate that stimulated PMN released EVs that altered the phenotype of naïve phagocytes by priming of the NADPH oxidase activity and augmenting phagocytosis, two responses that are integral to optimal PMN host defense.
Insights
Neutrophils release extracellular vesicles (EVs) that enhance the function of other immune cells. These neutrophil-derived EVs prime NADPH oxidase activity and boost phagocytosis, crucial for host defense.
Area of Science:
- Immunology
- Cell Biology
Background:
- Neutrophils (PMN) are key immune cells that regulate inflammation.
- Communication between immune cells, including via extracellular vesicles (EVs), is vital for immune responses.
Purpose of the Study:
- To investigate the functional properties of extracellular vesicles (EVs) released by activated human neutrophils.
- To determine how these neutrophil-derived EVs influence the phenotype and function of naïve phagocytes.
Main Methods:
- Human neutrophils were activated with N-formylmethionyl-leucyl-phenylalanine (fMLF).
- Extracellular vesicles (EVs) released from activated neutrophils (PMN-fMLF EVs) were isolated and characterized.
- Naïve neutrophils were treated with PMN-fMLF EVs, and their responses to subsequent stimulation were analyzed.
Main Results:
- PMN-fMLF EVs contained important neutrophil plasma membrane and granule proteins.
- Treatment with PMN-fMLF EVs primed naïve neutrophils, increasing NADPH oxidase activity and surface expression of complement receptors and CD66.
- EV treatment enhanced phagocytosis of opsonized Staphylococcus aureus.
Conclusions:
- Stimulated neutrophils release functional extracellular vesicles (EVs).
- These EVs alter the phenotype of naïve phagocytes by priming NADPH oxidase activity and augmenting phagocytosis.
- This process enhances neutrophil-mediated host defense mechanisms.
