Related Experiment Video
Updated: Jul 28, 2025
05:49
Procoagulant Platelet Characterization by Measuring Phosphatidylserine Exposure and Microvesicle Release from Human Purified Platelets
Published on: November 29, 2024
648
Phenotypic Characterization of Acoustically Enriched Extracellular Vesicles from Pathogen-Activated Platelets.
Frida Palm1, Axel Broman2, Genevieve Marcoux3
1Division of Infection Medicine, Department of Clinical Sciences, Lund, Lund University, Lund, Sweden.
Journal of Innate Immunity
|May 28, 2023
Summary
Bacterial M1 protein triggers release of platelet extracellular vesicles (EVs) containing M1 protein. These EVs promote inflammation and immune cell activation, revealing new insights into pathogen-driven platelet responses.
Area of Science:
- Immunology
- Hematology
- Microbiology
Background:
- Extracellular vesicles (EVs) are released from activated platelets and mediate hemostasis and immune responses.
- Platelet activation and EV release are heightened in inflammatory conditions like sepsis.
- The bacterial M1 protein from Streptococcus pyogenes activates platelets.
Purpose of the Study:
- To investigate the characteristics and inflammatory potential of EVs released from M1 protein-activated platelets.
- To understand the role of M1 protein in pathogen-mediated platelet activation and EV release.
Main Methods:
- Isolation of EVs from M1 protein-activated platelets using acoustic trapping.
- Quantitative mass spectrometry-based proteomics to analyze EV protein cargo.
- Cell-based models to assess the inflammatory phenotype of isolated EVs.
Main Results:
- M1 protein induced the release of platelet-derived EVs containing M1 protein.
- EVs from M1-activated platelets shared protein cargo with EVs from thrombin-activated platelets.
- Enriched immunomodulatory cargo, complement proteins, and IgG3 were found in M1-induced EVs.
- Isolated EVs demonstrated pro-inflammatory effects, including platelet-neutrophil complex formation and cytokine release.
Conclusions:
- M1 protein mediates the release of functional, pro-inflammatory platelet EVs.
- These findings elucidate novel mechanisms of pathogen-host interaction during invasive streptococcal infections.
- Platelet EVs are key mediators in the inflammatory response to bacterial pathogens.
Related Concept Videos
01:18Structure and Function of Platelets
1.3K
The cell fragments known as platelets are disc-shaped, with an average diameter of about 3 μm and a thickness of roughly 1 μm. They play a crucial role in the body's vascular clotting system, which also involves plasma proteins, blood cells, and blood vessel tissues.
Platelets are continually replenished, circulating in the bloodstream for 9-12 days before being removed by phagocytes, primarily in the spleen. A microliter of circulating blood contains between 150,000 and 450,000...
Platelets are continually replenished, circulating in the bloodstream for 9-12 days before being removed by phagocytes, primarily in the spleen. A microliter of circulating blood contains between 150,000 and 450,000...
1.3K
01:22Formation of the Platelet Plug
6.7K
The platelet phase, the second stage of hemostasis, commences around 15-20 seconds after an injury. It follows and overlaps with the vascular phase, during which blood vessels constrict to minimize blood loss.
As the injured blood vessel contracts, endothelial cells undergo contraction, revealing collagen fibers in the basement membrane and underlying connective tissue. Furthermore, the plasma membrane of endothelial cells becomes adhesive, preparing the site for platelet adhesion. Platelets...
As the injured blood vessel contracts, endothelial cells undergo contraction, revealing collagen fibers in the basement membrane and underlying connective tissue. Furthermore, the plasma membrane of endothelial cells becomes adhesive, preparing the site for platelet adhesion. Platelets...
6.7K