Exosomal RNA as biomarkers and the therapeutic potential of exosome vectors

Abstract

Introduction: Exosomes are nano-sized (40 – 100 nm), extracellular vesicles, of endosomal origin. They are released by cells and found in many body fluids, including plasma. Exosomes contain proteins, microRNAs (miRNAs), and messenger RNAs (mRNAs) that can be transferred between cells. The discovery that exosomes contain RNA, and that this encapsulated RNA could potentially be transferred over distances in vivo, reinforced the importance of exosomes in cell-to-cell communication.

Areas covered: The existence of exosomes, as a naturally occurring delivery system of RNA, enables their use as both biomarkers and vectors in gene therapy. This review provides an overview of studies reporting that exosomal miRNA and mRNA in plasma can serve as a diagnostic marker in various types of cancers. In addition, the recent finding that exosomes can be used as vectors for delivery of small interfering RNA (siRNA) in mice, with therapeutic effects, is also reviewed.

Expert opinion: The data reviewed here suggest that exosomal RNA has the potential to play an important role in the diagnosis, prognosis, and treatment of diseases in the future.

Keywords::

• biomarker
• exosomes
• extracellular vesicles
• gene delivery
• gene therapy
• microRNA
• mRNA
• siRNA
• vector

Acknowledgements

The author thanks SE O'Neil and M Sjöstrand, who critically reviewed and edited the manuscript.

Declarations of interest

The author has no competing interest to declare and has received no funding in preparation of this manuscript. However, colleagues of the author are co-owners of a patent for the use of exosomes as vectors for gene therapy.

Notes

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