ABSTRACT
Exosomes are heterogeneous population of nanoscale spherical lipid bilayer structures secreted by eukaryotic cells having a radius ranging from 20 to 60 nm. Exosomes package a wide array of biomolecules such as nucleic acids (DNA, miRNA, lncRNA), proteins and cytokines. These entities once thought to be a trash bag and structure of no significance have now been discovered to be involved in many important cellular processes, cell-to-cell communication(s) as well as in pathogenesis of many infectious agents. Several medical conditions have been found to involve changes in exosomal content and exosome-mediated cell–cell signaling. Content of the exosomes is found to be modulated not only by the state of cells but also varies in conditions viz. metabolic stress, cellular stress due to infection, cellular proliferation (cancerous tissue), and therefore serve as a wide array of biomarkers that can be targeted for early stage diagnosis of diseases. Exosomes have been identified as superior choice of delivery system over liposomes for treating human disease as they are better tolerated by immune cells and have efficient delivery rate. Many therapeutic materials (such as siRNA, recombinant proteins and immunomodulatory chemicals) are being investigated for packaging and delivery via exosome for efficient target treatment. These are also being exploited to develop novel vaccines, especially the exosome derived from immune cells as cell-free vaccine candidates for cancer therapy. Exosome biogenesis, heterogeneity and their diverse roles make them a clinically relevant biological tool that can be (i) used to study cell–cell interactions and unravel key aspects of many diseases; (ii) to design better diagnostics; and (ii) to develop novel and better therapeutics. In this chapter, we have discussed the significance of exosomes as novel biomarkers and applications in cutting-edge therapeutics.
