Functional Properties of Circulating Exosomes Mediated by Surface-Attached Plasma Proteins
Bibliographic record
Abstract
BACKGROUND: Exosomes and other types of extracellular vesicles present an important component of circulating plasma. Exosomes released by endothelial and blood cells account for majority of plasma exosomal population; exosomes secreted by other cells might cross tissue-plasma barrier and reach circulating plasma as well. Definitely, exosomes of different cellular origins are different by content and function. However, exosomal surface membrane interacts with plasma components. This interaction may alter composition of exosomal surface and hence, provide these vesicles with new functional properties. This study was aimed to estimate composition and possible functional role of proteins attached on the surface of plasma exosomes. METHODS: Here, extracellular vesicles from human plasma were isolated by ultracentrifugation and treated by trypsin. Trypsinized and native exosomes were analyzed by nanoparticle tracking analysis, Western blotting and quantitative high-resolution mass spectrometry. RESULTS: Surface-attached proteins were removed from exosomes isolated from plasma of healthy donors by incubation with serine protease (trypsin). Treatment did not impact exosomes integrity while slightly reduced hydrodynamic radius. Mass spectrometry revealed 259 exosomal proteins; among them 79 proteins were completely removed and more than half of the proteins were partially removed by trypsinization. Gene ontology functional annotation revealed mostly extracellular locations of proteins cleaved from a surface of the plasma exosomes. Moreover, proteins cleaved from the exosome surface are supposed to be implicated into integrin-linked kinase (ILK), focal adhesion kinase (FAK) and other pathways connecting cell surface with intracellular signaling cascades. CONCLUSION: Taken together, our results demonstrate that a surface of circulating exosomes is decorated by plasma proteins, and these proteins can mask tissue-specific characteristic of the exosomal surface membrane and provide exosomes with new and uniform properties.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".