Browsing by Subject "cellular uptake"
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(2017)Cells release different types of phospholipid bilayer-limited vesicles into the extracellular space. These are commonly referred to as extracellular vesicles (EVs). Exosomes (EXOs), ca 50-100 nm in diameter and microvesicles (MVs), ca 100-1000 nm in diameter, having different intracellular origin, are the two main subpopulations of EVs. EVs have been demonstrated to carry a range of proteins and nucleic acids subsequently delivered to recipient cells, making them attractive as drug delivery vehicles. Several mechanisms for the cellular uptake of EVs have been established. When a nanoparticle is introduced into blood plasma, plasma proteins are adsorbed to its surface, forming a protein corona. The formation of the corona is a dynamic process, governed by individual protein concentrations as well as their respective affinities for the surface. Proteins of the corona interact with surrounding cells, thus being able to influence the cellular uptake of the nanoparticle. In the current study, the uptake of PC-3-derived EVs into PC-3 cells was investigated. Moreover, the impact of a human blood plasma-derived protein corona on said uptake was assessed. EVs were isolated from collected PC-3 cell culture medium using differential centrifugation. Experiments were performed separately for MVs (20000xg EV-fraction) and EXOs (110000xg EVfraction). SDS-PAGE analysis revealed adsorption of plasma proteins to EVs, following their exposure to plasma. Prior to uptake experiments DiO-labelled EVs were either incubated or not incubated in plasma. Plasma incubation lasted overnight. PC-3 cells were then treated with either of the two EV-preparations. Following incubation, EV uptake was assessed using confocal microscopy by determining the percentage of positive fluorescent cells in cell cultures. Pre-study plasma incubation resulted in a reduced or unchanged uptake of MVs and in a reduced uptake of EXOs, when compared to their native counterparts. In conclusion, the plasma-derived protein corona was shown not to improve EV uptake. It is worth noting that the current study limits itself to the use of PC-3-derived EVs and PC-3 cells as recipient cells in uptake experiments.
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(2020)Extracellular vesicles (EVs) are a very heterogeneous group of cell originated nanoparticles that act as mediators of intercellular communication. Accurate characterization of EVs is essential to enable their wider use and development as possible biomarkers, drug carriers, and vaccines. There is no validated reference material with EV-like properties currently available. A validated reference material would improve the reliability and reproducibility of EV studies. Nanoerythrosomes (NanoE) have been studied as a possible option for biological reference material. We aimed to further characterize and compare properties of NanoEs and erythrocyte-derived EVs (EryEV) and assess their stability concerning concentration and size distribution at most commonly applied storage temperatures, +4°C, -20°C, and -80°C for 12 weeks. Characterization was done using nanoparticle tracking analysis and flow cytometry. In addition, we studied the surface protein expression including CD235a, CD47, and CD41 of NanoEs and EryEV and conducted a preliminary cellular uptake test using PC-3 cells, CFSE-labeled NanoE, and EryEV particles. For both, NanoE and EryEV samples, 20°C was the worst storage condition. NanoEs stay stable at +4°C for a month and at -80°C, there were some drops in concentration during the 12 weeks of the experiment. EryEVs stay stable at +4°C and -80°C for 12 weeks. Both NanoE and EryEV particles seemed to be taken into the PC-3 cells, but due to problems with autofluorescence we conclude that confirming studies with different labeling protocols or another method need to be conducted. Both NanoEs and EryEVs samples had a significant number of CD47-positive particles.
Now showing items 1-2 of 2