Formation of a protein corona on the surface of extracellular vesicles in blood plasma

Abstract

In this study we tested whether a protein corona is formed around extracellular vesicles (EVs) in blood plasma. We isolated medium‐sized nascent EVs of THP1 cells as well as of Optiprep‐purified platelets, and incubated them in EV‐depleted blood plasma from healthy subjects and from patients with rheumatoid arthritis. EVs were subjected to differential centrifugation, size exclusion chromatography, or density gradient ultracentrifugation followed by mass spectrometry. Plasma protein‐coated EVs had a higher density compared to the nascent ones and carried numerous newly associated proteins. Interactions between plasma proteins and EVs were confirmed by confocal microscopy, capillary Western immunoassay, immune electron microscopy and flow cytometry. We identified nine shared EV corona proteins (ApoA1, ApoB, ApoC3, ApoE, complement factors 3 and 4B, fibrinogen α‐chain, immunoglobulin heavy constant γ2 and γ4 chains), which appear to be common corona proteins among EVs, viruses and artificial nanoparticles in blood plasma. An unexpected finding of this study was the high overlap of the composition of the protein corona with blood plasma protein aggregates. This is explained by our finding that besides a diffuse, patchy protein corona, large protein aggregates also associate with the surface of EVs. However, while EVs with an external plasma protein cargo induced an increased expression of TNF‐α, IL‐6, CD83, CD86 and HLA‐DR of human monocyte‐derived dendritic cells, EV‐free protein aggregates had no effect. In conclusion, our data may shed new light on the origin of the commonly reported plasma protein ‘contamination’ of EV preparations and may add a new perspective to EV research.

Active antithrombin glycoforms are selectively physiosorbed on plasma extracellular vesicles

“…As demonstrated for synthetic nanoparticles 48 , EVs are able to recruit on their surface numerous proteins which are present at high concentrations in circulation. The nature of such “protein corona” has recently started to be investigated as for other biogenic nanoparticles 14, 39, 49, 50 . Such investigation promises to disclose new properties of EVs since EV protein corona might be involved in EV-mediated cellular communication or can even provide EVs with new regulatory functions.…”

Role of Extracellular Vesicle-Based Cell-to-Cell Communication in Multiple Myeloma Progression

“…Recent studies have shown that EVs can be 'decorated' with additional proteins besides the canonical exofacial molecules, collectively referred to as 'corona' [46][47][48][49][50][51][52]. Buzas et al [46] showed that EVs associate with extracellular matrix proteins, complement, immunoglobulins, coagulation factors, lipoproteins, nucleic acids, and thiol-reactive antioxidants [46].…”

“…Buzas et al [46] showed that EVs associate with extracellular matrix proteins, complement, immunoglobulins, coagulation factors, lipoproteins, nucleic acids, and thiol-reactive antioxidants [46]. Furthermore, Toth et al [51] confirmed the interaction between plasma proteins and EVs, and identified a number of proteins (ApoA1, ApoB, ApoC3, ApoE, complement factors 3 and 4B, fibrinogen α-chain, immunoglobulin heavy constant γ2 and γ4 chains) that form a 'corona' around EVs in blood plasma [51].…”

Increasing the Therapeutic Efficacy of Extracellular Vesicles From the Antigen-Specific Antibody and Light Chain Perspective

“…However, some of them can be acquired later in the extracellular space. Accordingly, recent study demonstrated the spontaneous formation of a protein corona around EVs in blood plasma ( Tóth et al, 2021 ). Very likely the acquired proteins impact EV’s properties and activity, which requires further investigation ( Tóth et al, 2021 ).…”

“…Accordingly, recent study demonstrated the spontaneous formation of a protein corona around EVs in blood plasma ( Tóth et al, 2021 ). Very likely the acquired proteins impact EV’s properties and activity, which requires further investigation ( Tóth et al, 2021 ). Similarly, our observations suggested the ability of EVs to bind freely circulating miRNAs ( Bryniarski et al, 2015 ).…”