From structures to functions: insights into exosomes as promising drug delivery vehicles

Abstract

Exosomes are small membrane vesicles secreted by most cell types, and appear ubiquitously in cell culture supernatants and body fluids. Increasing evidence supports that exosomes play important roles in intercellular communication, both locally and systemically, by transporting their contents such as proteins, lipids and RNAs between cells. Of particular interest for controlled drug delivery is that cell-derived exosomes offer the possibilities of overcoming biological barriers, thereby allowing the incorporated gene and drug to reach targeted tissue, which have been considerable challenges for synthetic carriers. Great research efforts have been dedicated to developing exosome-based drug delivery systems for the treatment of inflammatory diseases, degenerative disorders and cancer. In this review, we will describe the structural and functional properties of exosomes and emphasize current advances in the therapeutic applications of exosomes as drug delivery vehicles, followed by a discussion on current challenges and future perspectives.

Exosomal formulation of anthocyanidins against multiple cancer types

“…Exosomes are biological nanoparticles that are drawing great attention as drug delivery vehicle due to their cell-based origins [62–65]. Attempts have been made in the recent past to isolate exosomes from both non-cancerous and cancer cells in culture and fruit juices for delivering the chemotherapeutic drugs, doxorubicin [66,67], paclitaxel [68,69] and natural agents such as curcumin [70], withaferin A [19] and celastrol [49].…”

Hepatitis B virus X protein is capable of down-regulating protein level of host antiviral protein APOBEC3G

“…Results presented in this work suggest the existence of another potential mechanism of regulating intracellular A3G activity: altered A3G externalization through exosome secretion (Figs 5 and 6). Exosomes are known to contain lipids, proteins and nucleic acids derived from and characteristic of the producing cells23. Although exosome studies in recent years have tended to focus on its functions as a device for intercellular transport and communication, exosome secretion was initially discovered and characterized as a process of exporting and thereby reducing obsolete plasma membrane proteins during erythrocyte maturation353637.…”

“…Our data indicate that such down-regulation of A3G by HBx is most likely effected on already synthesized A3G proteins at the post-translational level, but does not seem to involve A3G protein degradation through proteasome or lysosome. Exosomes are small (~30–100 nm in diameter) membrane vesicles released by most cell types through fusion between intracellular multivesicular bodies (MVBs) and plasma membrane23. We provide evidences showing that intracellular A3G is normally exported in exosomes and such externalization of A3G is enhanced by HBx, which correlates with HBx-mediated down-regulation of intracellular A3G.…”

Telocytes and Their Extracellular Vesicles—Evidence and Hypotheses

“…Nowadays, the importance EVs in research is highlighted by the immense interest of the extracellular vesicle community, since EVs are considered as biomarkers, and also as drug, vaccine, and gene vector delivery tools in human diseases [27,28,29]. …”