In recent years, therapies utilizing extracellular vesicles have garnered significant attention among the industry stakeholders for the treatment of diverse target indication, primarily owing to the various benefits offered by them, including target specificity, enhanced tissue regeneration, and reduced inflammation and chronic pain. Over time, various research studies have demonstrated the potential of exosomes (membrane bound extracellular vesicles) in disease diagnosis, drug delivery and therapeutic applications. As a result, exosome therapeutics domain has been gaining traction recently.
INTRODUCTION TO EXOSOMES
Exosomes are extracellular vesicles, which have endosomal origin and may contain different biomolecules, including proteins, DNA, lipids, miRNA or RNA, based on the type of cell of their origin and its conditions.
Exosomes convey a wide range of information to the target cells, depending on their source. In addition, they are involved in regulating the expression of the targets that are linked to RNA as they can affect the expression of RNA.
TYPES OF EXTRACELLULAR VESICLES
Micro-vesicles have size of about 100 nm and are formed by direct outward budding of the plasma membrane. Their formation solely depends on the surrounding environment and this process requires the presence of cytoskeleton components, namely actin/
Exosomes have a diameter in the range between 30-150 nm and are formed by inward budding and get developed into the multivesicular bodies (MVBs). Owing to their long half-life, exosomes can target specific organs of the body, which makes them widely studied vesicles for immunological purposes.
Apoptotic bodies have a diameter of about 5,000 nm and formed after the separation of plasma membrane from the skeleton. They can be easily distinguished from micro vesicles and exosomes because of their unscathed organelles as well as chromatin.
SOURCES OF EXOSOMES
EXOSOME BIOGENESIS, FORMATION, DEVELOPMENT AND SECRETION
Exosomes are known to arise from the inward folding of multi-vesicular bodies (MVBs) in order to form the intraluminal vesicles (ILVs).
These MVBs are then delivered to the trans-Golgi network (TGN) for the recovery of endosomes, which further move to lysosome for degeneration of the carried substances. The most essential component of exosome biogenesis is the formation of ESCRT.
Formation and development of exosomes:
Sorting of internalized cargoes into early endosomes
Maturation into late endosomes or multivesicular bodies
Delivery of cargoes from trans-Golgi network and cytosol
Exosomes cargo in multivesicular bodies are transported to plasma membrane
Fusion with the plasma membrane
Secretion of exosomes
Secretion of Exosomes:
EXOSOMES AS THERAPIES:
ADVANTAGES AND FUTURE POTENTIAL OF EXOSOME THERAPEUTICS:
Exosome therapy holds several advantages, that deem them as potential drug candidates.