Current knowledge on exosome biogenesis and release

Abstract

Exosomes are nanosized membrane vesicles released by fusion of an organelle of the endocytic pathway, the multivesicular body, with the plasma membrane. This process was discovered more than 30 years ago, and during these years, exosomes have gone from being considered as cellular waste disposal to mediate a novel mechanism of cell-to-cell communication. The exponential interest in exosomes experienced during recent years is due to their important roles in health and disease and to their potential clinical application in therapy and diagnosis. However, important aspects of the biology of exosomes remain unknown. To explore the use of exosomes in the clinic, it is essential that the basic molecular mechanisms behind the transport and function of these vesicles are better understood. We have here summarized what is presently known about how exosomes are formed and released by cells. Moreover, other cellular processes related to exosome biogenesis and release, such as autophagy and lysosomal exocytosis are presented. Finally, methodological aspects related to exosome release studies are discussed.

Annexin A1 regulates EGFR activity and alters EGFR-containing tumour-derived exosomes in head and neck cancers

“…Given the role of ANXA1 in ILV formation and the reports that ILVs are precursors of exosomes, we speculated that ANXA1 could also play a role in exosome production in addition to its role in EGFR signalling termination [33,79]. Here, we observed a reduction in exosome production in HNSCC cell lines in response to ANXA1 knockdown.…”

Exosomes: recruits for tumour surveillance?

“…Subsequently it was discovered that three different types could be distinguished: microvesicles and apoptotic bodies (larger than 100 nm) and exosomes (up to 150 nm in diameter) (2). Exosomes are small vesicles derived from, and formed inside, the endosomal compartment ( Figure 1A).…”

“…Exosomes are small vesicles derived from, and formed inside, the endosomal compartment ( Figure 1A). Endosomal vesicles containing exosomes are called Multivesicular Bodies (MVBs) and they fuse with the cell membrane releasing the exosomes outside the cell (2). Exosomes can subsequently be uptaken by other cells trough clathrin-independent pathways ( Figure 1B) (3).…”

“…Exosomes can subsequently be uptaken by other cells trough clathrin-independent pathways ( Figure 1B) (3). In this way their content can be transferred from cell to cell (2,5). Firstly formally described in 1987 (6) they were, according to a pattern very common in science, first dismiss as artefact and subsequently as of no interest (7).…”

“…Firstly formally described in 1987 (6) they were, according to a pattern very common in science, first dismiss as artefact and subsequently as of no interest (7). It has been only after some years that their importance has been eventually acknowledged (2,5,7).…”