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ASEMV 2019 Annual Meeting on Exosomes & Microvesicles Opened Sunday Evening, October 6, at Asilomar in Pacific Grove, California

The 2019 annual meeting of the American Society for Exosomes and Microvesicles (ASEMV) was held October 6-10 at the gorgeous Asilomar Conference Grounds in Pacific Grove, California, home of migrating monarch butterflies, steps from the Pacific Ocean, and just 120 miles south of San Francisco. The glorious natural setting was almost matched perhaps by the broad range of 60 scintillating presentations delivered by scientists from around the country and world, during the five intense days of meetings focused on one of the most exciting aspects of biology and mediicine. This year’s meeting, organized as always by Stephen Gould, PhD, of Johns Hopkins, began on Sunday evening with a brief introduction on the history of the ASEMV annual meetings by Michael Graner, PhD, University of Colorado-Denver, and this was followed by the keynote presentation, sponsored by Caris Life Sciences, and delivered by Dr. Travis Thomson of the University of Massachusetts (Worcester, MA). Dr. Thomson’s address was titled “Arc and Copia in Exosome-Mediated Information Exchange.” Dr. Thomson described Arc as a “master regulator of neuronal plasticity and as a remnant of a transposon gag region of a virus. In a 2018 article in Cell (https://www.ncbi.nlm.nih.gov/pubmed/29328915), Dr. Thomson and colleagues noted that Arc/Arg3.1 is required for synaptic plasticity and cognition, and mutations in this gene are linked to autism and schizophrenia. Arc bears a domain resembling retroviral/retrotransposon Gag-like proteins, which multimerize into a capsid that packages viral RNA. The significance of such a domain in a plasticity molecule is uncertain. In the Cell article, Dr. Thomson and colleagues reported that the Drosophila Arc1 protein forms capsid-like structures that bind darc1 mRNA in neurons and is loaded into extracellular vesicles (EVs) that are transferred from motor neurons to muscles. This loading and transfer depend on the darc1-mRNA 3' untranslated region, which contains retrotransposon-like sequences. Disrupting transfer blocks synaptic plasticity, suggesting that transfer of dArc1 complexed with its mRNA is required for this function. Notably, cultured cells also release extracellular vesicles containing the Gag region of the Copia retrotransposon complexed with its own mRNA. Taken together, Dr. Thomson and colleagues concluded that their results point to a trans-synaptic mRNA transport mechanism involving retrovirus-like capsids and extracellular vesicles.” Dr. Thomson described Arc and Copia as having opposite effects on neuronal plasticity, with Arc being a positive regulator, and Copia, a negative regulator, of neuronal plasticity, with the balance between the two possibly being at the level of EVs.

REASSESSMENT OF EXOSOME BIOGENESIS

Following Dr. Thomson’s address, which Dr. Graner described as “very exciting,” Dr. Gould presented a “Reassessment of Exosome Biogenesis.” Dr. Gould described recent results demonstrating that the plasma membrane is a major site of exosome biogenesis, and that, more importantly, cells possess a common pathway for exosome protein budding that operates at both plasma and endosome membranes. “Using a combination of single-particle interferometry reflectance (SPIR) imaging and immunofluorescence microscopy, we also show that variations in exosome composition are controlled by differential intracellular protein trafficking rather than by separate mechanisms of exosome biogenesis.” According to Dr. Gould and colleagues, “This new view of exosome biogenesis offers a simple explanation for the pronounced compositional heterogeneity of exosomes and a validated roadmap for exosome engineering.” In his presentation, Dr. Gould also mentioned that he had recently co-written a review of exosomes in 2019 Annual Reviews of Biochemistry (https://www.annualreviews.org/doi/abs/10.1146/annurev-biochem-013118-111902).

TANGENTIAL FLOW FILTRATION A HIGHLIGHT OF ASEMV TECHNOLOGY WORKING GROUP MEETING

The closing presentation of Sunday’s evening session, was delivered by Dr. Louise Laurent, MD, PhD, of University of Califonrnia-San Diego (UCSD) who summarized highlights of the earlier-in-the-day ASEMV Technology Working Group. Among these highlights, Dr. Laurent noted that “tangential flow filtration” is a “very exciting technology.”

PRELUDE TO FOUR MORE DAYS OF EXCITING SCIENCE

These exciting, thought-provokng presentations served as a fitting launch to the four following days of exciting science.

SPONSORS OF ASEMV 2019 ANNUAL MEETING

Sponsors of the ASEMV 2019 annual meeting included Particle Metrix, System Biosciences (SBI), iZON, Caris Life Sciences, NanoView Biosciences, Wako, AcouSort, Beckman-Coulter, Ellarcus Biosciences, LMNX, Malvern, Spectradyne Particle Analysis, Fiber Cell Systems, ONI, Nanostatistics Precision Health, Norgen Biotech, HansaBioMed Life Sciences, and Lonza.