Omes expressing PrX-GFP exhibited 100-fold increase in relative fluorescence compared to LAMP2B and pDisplay GFP fusions. Comparable REV-ERB Proteins Accession levels of high-density expression have been accomplished using a number of topologically diverse therapeutic proteins fused to full-length or truncated types of PrX. Exosomes engineered to show IL7, CD40 ligand, IL12 and antibody fragments via PrX fusion exhibited up to 1500-fold improvement in potency compared to previously described scaffolds. Summary/Conclusion: This work demonstrates the possible of our engEx platform to create novel exosome therapeutics, especially via high density surface display mediated by PrX.PS01.Leptin-loaded macrophage-derived exosome: high-efficiency loading approach and its properties Ryo Kojima, Elena Batrakova and Alexander Kabanov University of North Carolina at Chapel Hill, Chapel Hill, USAIntroduction: Membrane proteins preferentially partitioned into exosomes can be co-opted to display pharmacologically active molecules on the exosome surface, which is a vital technique for maximizing the prospective of therapeutic exosomes. Previously published approaches have relied on “canonical” scaffolds which includes multi-pass transmembrane tetraspanins (CD9/ CD63/CD81), LAMP2B, or non-exosomal domains like pDisplay or GPI anchors. We sought to determine novel scaffolds that allow much more uniform, greater density surface display of structurally and biologically diverse molecules. Approaches: Proteomic evaluation of stringently purified exosomes led towards the identification of highly abundant and distinctive exosomal proteins, including a single-pass transmembrane glycoprotein (Protein X, PrX) belonging towards the immunoglobulin superfamily. Protein X andIntroduction: Exosome, one of extracellular vesicles, is regarded to be an essential player in intercellular communication. Application of exosome to drug delivery program is expected to target distinct cells. Especially macrophage-derived exosome is recognized to cross blood rain barrier (BBB) and deliver its cargo soon after intravenous administration. Leptin is hormone to regulate power balance by inhibiting hunger, and leptin receptor is located on Thy-1/CD90 Proteins Source neurons of hypothalamus. Drug delivery system of leptin to brain is anticipated due to the fact leptin transporter at BBB is recognized to be impaired in obesity models. Nonetheless, it has been difficult to loadISEV2019 ABSTRACT BOOKenough volume of protein drugs into exosome devoid of changing its original properties. Purposes of this research are to develop leptinloading technique into exosome with high efficiency and to evaluate its physicochemical and biological characteristics. Methods: Exosome was isolated from IC-21 (mouse macrophage) cells by an ultracentrifuge technique. Particle-size distribution on the exosome was measured by Nanoparticle Tracking Analysis. Expression of exosome-marker protein was confirmed by Simple Western. Leptin was loaded into the exosome by using a probe sonicator, and totally free leptin was removed by gel filtration chromatography. Loaded amount of leptin was measured by ELISA. Release profile of leptin in the exosome was evaluated in mouse serum at 37C. In order to evaluate protection capacity of exosome formulation against protease, the leptin-loaded exosome was treated with pronase and remained leptin was quantified. Stability with the exosome was also investigated. Outcomes: IC-21 derived exosome had 10010 nm of mean size and contained exosomal markers, for example Alix and Rab11A. Size distribution and exos.