Characterization of RNA in Extracellular Vesicles

Extracellular vesicles (EVs) are important players in the communication between different kinds of cells by delivering their content, consisting of different types of RNA, proteins, bioactive lipids, or signaling nucleotides, into their target cells. Several types of EVs are distinguished: (1) exosomes with sizes from 30 to 150 nm originate from the endosomal pathway and form intracellular multivesicular bodies (MVBs), which fuse to the plasma membrane before their secretion. (2) EVs with sizes ranging from 100 to 1000 nm in diameter are formed during cell surface budding. (3) Apoptotic bodies with diameters from 500 to 2000 nm are released from blebbing of the cell membrane of apoptotic cells. It is well established that various RNA molecules such as coding RNAs and noncoding RNAs (long noncoding RNAs, microRNAs, circular RNAs, and rRNAs) are present in different amounts in EVs depending on the type and origin of EV. Here we will give an overview of methods to isolate different types of EVs and to quantify and characterize different RNA species.