Ckaging and release from cells. In vivo, we administered exosomes by means of nasal delivery, a method we have previously identified to deliver functional exosomes to the brain. In each wild form and -synuclein transgenic mouse brains we observed Lewy body-like aggregates following delivery of exosomes containing -synuclein. Delivery of control exosomes did not lead to brain aggregates, similarly, delivery of -synuclein containing exosomes to -synuclein knockout mice didn’t result in brain aggregates. Behavioural testing showed that animals given synuclein containing exosomes had movement deficits in their hind limbs, whereas animals provided control exosomes or -synuclein exosomes to knockout mice did not display any behavioural deficits. Summary/Conclusion: Here we identified a mechanistic pathway for the packaging of -synuclein into exosomes and show that these exosomes are capable to propagate aggregated forms of the protein to the brains of rodents. These findings show how exosomes can transmit -synuclein in the brain resulting in Lewy body-like aggregates and movement deficits which can be identified in Parkinson’s illness. Funding: This function was funded by NHMRC project grants awarded to J Howitt.Friday, 04 MaySymposium Session 13 – Part of Tumour EVs in Cell-Cell Communication Chairs: Antonella HPV E6 Proteins MedChemExpress Bongiovanni; Hector Peinado Place: Auditorium 13:45 – 15:OF13.Laptop or computer guided image analysis of SARS-CoV-2 Non-Structural Proteins manufacturer nuclear membrane instability in tissues reveals clinical relevance for nucleus-derived EVs Tatiana Novitskya1; Adel Eskaros1; Mariana Reis-Sobreiro2; Michael R Freeman2; Dolores Di Vizio2; Andries ZijlstraDepartment of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA; 2Departments of Surgery, Biomedical Sciences, and Pathology and Laboratory Medicine, Cedars-Sinai Health-related Center, Los Angeles, CA, USABackground: Though it can be effectively established that oncogenic transformation causes cells to shed a heterogeneous population extracellular vesicles (EV), dependable solutions for evaluating and quantifying the biogenesis of EV in patient tissue have already been lacking. In prior studies of prostate cancer, we observed comprehensive EV shedding and enhanced malignant behaviour in cancer cells that exhibit nuclear instability. Nuclear blebbing and shedding of EV containing genomic material could be detected in tumour tissue from experimental models of nuclear membrane instability generated by depletion from the cytoskeletal regulator DIAPH3 or nuclear lamin A/C. To figure out the clinical significance of this mechanism in prostate cancer, we created a novel approach towards the quantitative evaluation of EV production in formalin-fixed paraffinembedded clinical tissues. Methods: To visualize release of nucleus-derived particles, multiplex immunofluorescent detection of nuclear histone, DNA and nuclear envelope (Emerin) together with all the epithelial cytokeratin (CK18) was performed on a tissue microarray containing tumour, adjacent benign and metastatic LN tissue (n = 80). Machine learning was leveraged, for the very first time, to develop an image evaluation pipeline that enabled singlecell segmentation and quantitation of nucleus-derived EV linked with nuclear membrane instability. Outcomes: Nucleus-derived EV was evident in 50 of prostate cancer sufferers and 80 of tumour-involved lymph nodes. Intra-patient differences in particle size, place and enumeration suggest that significant variation within the mechanisms of biogenesis may exist. Most importantl.