ABSTRACT

Exosomes, unlike shedding vesicles, express molecules such as TSG101, Alix, HSC70, CD81, CD63, CD9, and a low content of PS.16 Other classes of vesicles include gesicles with a size of 100 nm and exosome-like vesicles with sizes ranging from 20 nm to 50nm, expressing the full-length 55 kDa tumor necrosis factor (TNF) receptor-1.17 Cells simultaneously produce several types of EVs bearing a specific cargo and potentially capable of different biological activities.13 Moreover, membrane composition and also the size of vesicles may differ depending on the cell of origin; it is therefore difficult to exactly categorize different EVs. Irrespectively of their origin, EVs contain cytosol delimited by a plasma membrane expressing proteins and receptors from the cell of origin; nucleic acids are also present in both exosomes and shedding vesicles. Even though the exact physiological role of EVs remains to be elucidated, it is becoming clear that they may transfer proteins, receptors, bioactive lipids, messenger ribonucleic acid (mRNA), and micro-RNA (miRNA) from the cell of origin to the recipient cell, which may modify their phenotype and functions.18,19 Interestingly, high-density lipoprotein (HDL) and low-density lipoprotein (LDL), which are the other major lipid-based particles in the plasma, also contain miRNAs. Highly pure HDL fractions were found to contain distinct miRNA signatures, which are altered in cardiovascular diseases. Furthermore, HDL was demonstrated to deliver miRNAs to Huh7 hepatocellular carcinoma cells.20