Nt reports suggest that these vesicles may possibly play essential roles in both regular physiology plus the pathogenesis of several disease states, such as cancer. Nonetheless, their biological significance as well as the underlying molecular mechanisms of their biogenesis and release remain largely unknown. Solutions: Taking advantage of current expertise of exosomemediated microRNA export, we created artificially barcoded-exosomal microRNAs (bEXOmiRs) to study this procedure. bEXOmiR reporters include a 15 nt-random sequence that may be detected quantitatively by next generation sequencing. Pooled cell cultures expressing single bEXOmiRs in each and every cell have been utilised to monitor bEXOmiR abundance in exosome preparations. We could then express pairs of exclusive CRISPR guide (sg)RNAs related with individual bEXOmiRs and establish how knockout of every gene influenced the release of microRNAs in isolated exosomes from large-scale suspension cultures of Cas9-edited cells. To be able to carry out a genome-wide screen, we have employed this technology in conjunction with 250,000 sgRNA-bEXOmiR pairs. Outcomes: As anticipated, subsequent generation sequencing revealed a gene signature constant with prior research inside the field, including recognized regulator positive controls. A large number of new genes were identified with E2 Enzymes Proteins custom synthesis previously unrecognized roles in extracellular microRNA export and their involvement has been validated by orthogonal assays. Summary/Conclusion: Altogether, next generation sequencing evaluation of barcoded microRNA abundance coupled with CRISPR-Cas9 screening represents a powerful and unbiased means for the systematic discovery of genes involved in microRNA packaging and extracellular vesicle release. Funding: This study was funded by the U.S. National Institutes of Well being grant DK37332.ISEV 2018 abstract bookFA3.Systematic methodological evaluation of a multiplex bead-based flow cytometry assay for detection of extracellular vesicle surface signatures Oscar PB Wiklander1; Beklem Bostancioglu1; Ulrika Felldin1; Antje Zickler2; Florian Murke3; Joshua A. Welsh4; Bj n Evertsson5; Xiu-Ming Liang1; Giulia Corso1; Manuela Gustafsson1; Dara Mohammad1; Delta-like 1 (DLL1 ) Proteins Recombinant Proteins Constanze Wiek6; Helmut Hanenberg6; Michel Bremer3; Dhanu Gupta1; Mikael Bj nstedt2; Jennifer Jones7; Bernd Giebel8; Joel Z. Nordin1; Samir El-Andaloussi9; AndrG gens9 Clinical Study Center, Division for Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden, Stockholm, Sweden; 2Division of Pathology F56, Department of Laboratory Medicine, Karolinska Institutet, Karolinska University Hospital Huddinge, Stockholm, Sweden, Stockholm, Sweden; three Institute for Transfusion Medicine, University Hospital Essen, University of Duisburg-Essen, Essen, Germany, Essen, Germany; 4Molecular Immunogenetics and Vaccine Investigation Section, Vaccine Branch, CCR, NCI, NIH, Bethesda, MD, USA, Bethesda, USA; 5Department of Clinical Neuroscience, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden, Stockholm, Sweden; 6Department of Hematology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany, Essen, Germany; 7National Cancer Institute, Bethesda, USA; 8Institute for Transfusion Medicine, University Hospital Essen,, Essen, Germany; 9Clinical Study Center, Department for Laboratory Medicine, Karolinska Institutet, Stockholm, H sov en, SwedenDepartment of Biochemistry and Genetics, La Trobe Institute for Molecular Science, Australia, Melbourne, Australia; 2Department of Biochemistry and Genetics,.