Just learning about exosomes? The team at SBI has put together this brief overview to help get you started in the growing field of exosome research.

What are exosomes?
Exosomes are a type of extracellular vesicle (EV) with a diameter of between 30 and 200 nm. While EV nomenclature can be varied and controversial (8), one way to categorize different types of EVs is through the part of the cell they are derived from. Using this method, exosomes are defined as being endocytic in origin, produced by the inward budding of multivesicular bodies (MVBs). They are released from the cell into the microenvironment following fusion of MVBs with the plasma membrane.

Why are exosomes important?
Once thought to be little more than a way for cells to offload waste, the past decade has seen a huge shift in the way we think about exosomes (1). We've begun to recognize that exosomes are deliberately released from the cell, functioning as signal carriers through their cargo of RNA, proteins, lipids, and DNA (2-7). Involved in a wide range of healthy and pathogenic processes - cancer, inflammation, immunity, CNS function, cardiac cell function, to name a few - exosomes are being studied for their role in these basic biological processes as well as for their use as biomarkers and even as tools for targeted delivery of biomolecules as therapeutics.

Where are exosomes normally found?
Exosomes have been found in blood, urine, amniotic fluid, breast milk, malignant ascites fluids, and seminal fluid (7,9). They contain distinct subsets of molecules depending upon the cell type from which they are secreted, making them useful for biomarker discovery (7,9).

How do I study exosomes?
SBI is the only vendor to offer reagents and kits that support all aspects of exosome research - covering isolation, detection and measurement, discovery (characterization and analysis), and even exosome engineering. With a comprehensive set of tools and services to accelerate the study of exosomes and exosome RNA biomarkers, SBI puts the power of exosomes into researchers' hands.

REFERENCES

1. Thery, C. Exosomes: secreted vesicles and intercellular communications. F1000 Biol. Rep. 3, (2011).
2. Couzin, J. Cell biology: The ins and outs of exosomes. Science 308, 1862-1863 (2005).
3. Waldenstrom, A. & Ronquist, G. Role of exosomes in myocardial remodeling. Circ. Res. 114, 315-324 (2014).
4. Sun, Y. & Liu, J. Potential of cancer cell-derived exosomes in clinical application: a review of recent research advances. Clin. Ther. 36, 863-872 (2014).
5. Braccioli, L., van Velthoven, C. & Heijnen, C. J. Exosomes: a new weapon to treat the central nervous system. Mol. Neurobiol. 49, 113-119 (2014).
6. Thebaud, B. & Stewart, D. J. Exosomes Cell Garbage Can, Therapeutic Carrier, or Trojan Horse? Circulation 126, 2553-2555 (2012).
7. Pant, S., Hilton, H. & Burczynski, M. E. The multifaceted exosome: biogenesis, role in normal and aberrant cellular function, and frontiers for pharmacological and biomarker opportunities. Biochem. Pharmacol. 83, 1484-1494 (2012).
8. Richard J. Simpson & Suresh Mathivanan. Extracellular Microvesicles: The Need for Internationally Recognised Nomenclature and Stringent Purification Criteria. J Proteomics Bioinform 5, ii-ii (2012).
9. Witwer, K. W. et al. Standardization of sample collection, isolation and analysis methods in extracellular vesicle research. J. Extracell. Vesicles 2, (2013).