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“Zone in with Zon”—Exosomes: Tiny Packets of RNAs with Major Significance and Potential

Dr. Gerald Zon’s latest “Zone in with Zon” blog post, dated September 23, 2013, focuses on a discussion of “exosomes,” tiny ~30-100 nm extracellular vesicles discovered 30 years ago. These exosomes are released from cells and can fuse with the membrane of target cells and enable the transmission of exosome informational cargo, e.g., protein and RNA, into the target cell. According to Dr. Zon, “the ability to influence gene expression in distant cells through exosomes presents a remarkable model for cell-to-cell signaling that offers an entirely new perspective on intercellular communication. This also has potential therapeutic applications, such as in diagnosis, intervention, and artificial gene/mRNA delivery.” Dr. Zon cites an explosion of exosome-focused peer-reviewed articles in the last ten years, as evidence of increasing awareness of the importance of these information-loaded vesicles. He also highlighted a 2007 article by Valadi et al. that reported that exosomes from mast cells contained mRNA from ~1,300 genes, many of which were not present in the cytoplasm of the donor cell. He noted that in vitro translation showed that the exosome mRNA was functional and analysis of total RNA from the exosomes revealed the presence of small RNAs, including miRNAs. In addition, the RNA from mast cell exosomes was transferrable to other mast cells. Dr. Zon said this publication has been cited more that 1,300 times, particularly in the molecular biology of cancer. Dr. Zon goes on to discuss recent work documenting the release of exosomes by the human placenta into maternal circulation throughout pregnancy, as well as the role of tumor-released exosomes in promoting cancer developmement. Dr. Zon closes with a discussion of how commercial companies have been quick to provide tools for exosome analysis, and also to begin developing exosome-based diagnostics and therapeutics. He points out that NIH has recently announced its intention to award $17 million to fund 24 new research projects to understand how exosomal RNA is involved in communication between cells and how these RNAs may be used as biomarkers for diseases. He also noted the recent formation of two exosome-focused scientific organizations: the International Society for Extracellular Vesicles and the American Society for Exosomes and Microvesicles. Dr. Zon is an eminent nucleic acid chemist and Director of Business Development at TriLink BioTechnologies in San Diego, California. [Zon blog post] [International Society of Extracellular Vesicles] [International Society of Extracellular Vesicles blog] [American Society for Exosomes and Microvesicles] ["Exosomes: The Little Vesicles That Could"] [Exosome-Based Communication in Malaria]