Thirty (30) years ago, exosomes were first described as extracellular vesicles (References 1 and 5). Extracellular vesicles (EVs) are cell derived membrane structures. They are secreted as a result of fusions between intracellular endosomes and the plasma membrane.  Alternatively, they are dispensed from the plasma membrane as microvesicles. Since their initial discovery, exosomes have become implicated in the mechanisms of intercellular signaling (aka. cell-to-cell signaling) and cell-to-cell maintenance of homeostasis. Since their initial discovery, EVs have gained much respect in the cell biology world. They are represented as an important mechanism of cell-to-cell communication — transferring cell membranes, cytosolic proteins, lipids, DNA, RNA, microRNA, etc. 

Here are some highlighted features:

  1. EVs from mammalian cells carry RNAs, proteins, and lipids from their parental cells.
  2. EVs range from submicron sized particles to nanometer sized exosomes (50nm-400nm in diameter).
  3. Membranes of EVs can be natively produced or engineered to enhance targeting effects (Ref 2).

Potential clinical applications relevant for patients:

  1. For diagnostic applications, EVs can serve as unique candidates for diseases (see applications in cancer; Ref 3).
  2. Clinical grade (GMP-grade) biomanufacturing of EVs may be applied as therapeutic agents (see applications in cancer; Ref 4 and 6).

Diagnostics and clinical applications of exosomes — who is working on them?

  • Codiak Biosciences (USA)
  • Evox Therapeutics (UK)
  • Exosome Diagnostics (USA; parent company is BioTechne)
  • EXoPERT (South Korea)
  • ExoCoBio (South Korea)
  • Aruna Bio (USA)
  • Versatope Therapeutics (USA)
  • HansaBioMed Life Sciences Ltd (EU; parent company is Lonza)
  • NanoSomiX Inc (USA)

To explore exosomes further, please see references below and visit the ExoCarta and Vesiclepedia for more information! One mystery that has yet to be addressed is whether different cell types in the human body harbor unique populations of exosomes and EVs and how do these nanovesicles “know” who are their target cells? 

References:

  1. https://bmcbiol.biomedcentral.com/articles/10.1186/s12915-016-0268-z
  2. https://www.sciencedirect.com/science/article/pii/S014296121301449X
  3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6631586/ 
  4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5931131/
  5. https://www.physiology.org/doi/abs/10.1152/physiol.00045.2018
  6. https://www.sciencedirect.com/science/article/abs/pii/S095816691830140