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Updated: Jul 17, 2026
Isolation, Characterization, and Proteomic Analysis of Plasma-Derived Extracellular Vesicles for Cardiovascular Biomarker Discovery
Published on: January 31, 2025
Proteomic discovery of 21 proteins expressed in human plasma-derived but not platelet-derived microparticles
David M Smalley1, Karen E Root, Hyungjun Cho
1Mellon Medical Biomarker Discovery Laboratory, Robert M. Berne Cardiovascular Research Center, Charlottesville, VA 22908-1294, USA.
Abstract:
Microparticles (MPs) are small membrane vesicles generated by essentially all cell types. In the plasma, most MPs are derived from platelets, but those from other sources, particularly leukocytes (macrophages, lymphocytes, and neutrophils), endothelial cells, and even smooth muscle cells can be detected and appear to play an important role in normal physiology and various diseases. In previous work we analyzed the proteome of MPs generated from isolated platelets (platelet MPs). Here, we report on a comparative analysis of microparticles isolated from plasma (plasma MPs) versus platelet MP using two complementary methods of comparative analysis. The first method, spectral count analysis, yielded 21 proteins detected in plasma MPs (with a total spectral count of 10 or greater) that were essentially absent in platelet MPs (with a total spectral count of 1 or 0). An additional two proteins (von Willebrand Factor, albumin) were present in both types of MPs but enriched in the plasma MPs. The second method, isotope-coded affinity tag (ICAT) labeling of proteins, supported the spectral count results for the more abundant proteins and provided better relative quantitation of differentially expressed proteins. Proteins present only in the plasma MPs include several associated with apoptosis (CD5-like antigen, galectin 3 binding protein, several complement components), iron transport (transferrin, transferrin receptor, haptoglobin), immune response (complement components, immunoglobulin J and kappa chains), and the coagulation process (protein S, coagulation factor VIII).
Insights
This study compares plasma microparticles (MPs) to platelet MPs, identifying unique proteins in plasma MPs involved in apoptosis, iron transport, immune response, and coagulation. These findings highlight distinct roles for different MP types in health and disease.
Area of Science:
- Biochemistry
- Cell Biology
- Proteomics
Background:
- Microparticles (MPs) are vesicles released by cells, with platelet MPs being most common in plasma.
- MPs from leukocytes, endothelial cells, and smooth muscle cells also exist and have physiological/pathological roles.
- Previous work characterized platelet MP proteome; this study compares plasma MPs to platelet MPs.
Purpose of the Study:
- To comparatively analyze the proteome of plasma microparticles (plasma MPs) versus platelet microparticles (platelet MPs).
- To identify proteins uniquely present or enriched in plasma MPs compared to platelet MPs.
Main Methods:
- Comparative proteomic analysis using spectral count and isotope-coded affinity tag (ICAT) labeling.
- Quantification of protein abundance in plasma MPs and platelet MPs.
Main Results:
- 21 proteins were detected in plasma MPs but absent in platelet MPs (spectral count >= 10).
- Von Willebrand Factor and albumin were enriched in plasma MPs.
- Plasma MP-specific proteins are associated with apoptosis, iron transport, immune response, and coagulation.
Conclusions:
- Plasma MPs contain a distinct proteomic profile compared to platelet MPs.
- These unique proteins suggest specific roles for plasma MPs in biological processes like apoptosis, iron metabolism, immunity, and hemostasis.
- Further research into plasma MP composition can elucidate their roles in disease.
