The recent advances in translational and nanomedicine have paved the way for developing the targeted drug delivery system at a greater pace among global researchers. On par with these technologies, exosomes act as a potential portal for cell-free drug delivery systems as these are bestowed with the native characteristics of the parent cell of origin. Exosomes, called extracellular vesicles (EcVs), are present in almost all cells, tissues, and body fluids. They help in intercellular signaling and maintains tissue homeostasis in the disease pathobiology. Researchers have characterized 9,769 proteins, 2,838 miRNAs, 3,408 mRNAs, and 1,116 lipids being present in exosomal cargo. The separation of exosomes from cells, tissues, and body fluids follow different patterned kinetics. Exosomes interact with the recipient cells through their surface receptor molecules and ligands and internalize within recipient cells through micropinocytosis and phagocytosis. Advancing technologies in regenerative medicine have facilitated the researchers to isolate exosomes from mesenchymal stem cells (MSCs) as these cells are blessed with supreme regenerative potentiality in targeting a disease. Exosomal cargo is a key player in establishing the diagnosis and executing therapeutic role whilst regulating a disease process. Various in vitro studies have exhibited the safety, efficacy, and therapeutic potentiality of exosomes in various cancers, neurodegenerative, cardiovascular, and orthopedic diseases. This article throws light on the composition, therapeutic role, and regulatory potentials of exosomes with the widening of the horizon in the field of regenerative medicine.
Introduction
The contemporary developments in the field of translational medicine include the development of targeted drug delivery systems for harnessing the full potentiality and utilizing the therapeutic products effectively by overcoming the limitations of the existing methods to address the pathogenesis of a disease. In that context, various polymer-based nano delivery systems have been developed (1). Utilizing extracellular vesicles (EcVs) as a drug delivery tool has been given special attention due to their naïve characteristics derived from the parent or host cells (2–4). Despite the normal cellular homeostasis, EcVs play a major role in intervening in the pathobiology of disease processes through the intercellular signaling cascade (5–9).
Based on the size, exosomes are subcategorized under EcVs, which are endosome derived lipid bi-layered spherical vesicles of 40–150 nm in size (2,10–12). Almost all cells, tissues, and body fluids [plasma, urine, saliva, tears, gastrointestinal (GI) secretions, semen, and breast milk] secrete exosomes (13–16). Exosomal cargo carries an array of micro-biomolecules that consists of proteins, lipids, RNA, and DNA from the secreting parent cells (2,17–19). Moreover, the characteristics and behavior of the exosomes closely relate to the parent cell of origin (20–22). On account of their appropriate size and property along with their evident role in numerous pathobiological processes, the potential of exosomal therapy in the management of various neurodegenerative disorders, infectious diseases, musculoskeletal disorders, and cardiovascular disorders is overwhelming. This has enabled the researchers to target the disease process at a cellular level by using natural engineered defense mechanisms.
