The Role of Extracellular Vesicles (EVs) and EV-cargo in virally-mediated CNS diseases.

Objective: To characterize extracellular vesicle and EV-cargo in virally-mediated CNS diseases. To elucidate EV-mediated host-pathogen dynamics in virally-mediated CNS diseases. Background: Extracellular vesicles (EVs) have gained increased attention as novel orchestrators of intercellular communication and key mediators of pathogen-host dynamics in viral infections. In HTLV-associated myelopathy (HAM), HTLV-1 specific T cells are identified in the CSF of patients in the absence of cell-free virus. In Progressive Multifocal Leukoencephalopathy (PML), caused by JC virus, infected cells lack the viral receptors for JCV, however post-mortem autopsy samples of PML patients demonstrate JCV within these same cells. We hypothesize that a subset of neuroinvasive viruses exploit EVs in order to promote viral spread and chronic inflammation. Design/Methods: This is a proof-of-principle pilot study to determine the feasibility of isolating and characterizing EVs from study participants in our Neuroimmunology clinic. Study participant CSF and serum were analyzed for EVs by several methods. Exosome isolation was performed with qEV SEC columns or MagCapture Exosome Isolation Kit PS. EV concentration and size distribution was determined by microfluidics resistive pulse sensing (MRPS). Exosome markers (CD63, CD9, CD81) were detected by Western Blot. JCV viral DNA was detected by ddPCR. Results: EVs were successfully isolated from the CSF or serum of PML, HAM, multiple sclerosis (MS) and healthy volunteers (HV). qEV SEC isolation demonstrated EV heterogeneity in the size and type of EVs in HAM, MS, HV. Paired serum-CSF exosome analysis revealed distinct exosome populations in the periphery vs. CNS compartment. MRPS allowed for the characterization of CSF-derived EVs in the absence of EV isolation. Conclusions: Our preliminary results demonstrate the feasibility of isolating various EV subpopulations from the serum and CSF of healthy and diseased study participants. Ongoing studies are aimed at validating these findings in a larger cohort and further characterizing the role of EVs in neuroinvasive CNS diseases. Disclosure: Dr. Magana has nothing to disclose. Dr. Pleet has nothing to disclose. Dr. Monaco has nothing to disclose. Dr. Ngouth has nothing to disclose. Dr. Montojo has nothing to disclose. Dr. Kashanchi has nothing to disclose. Dr. Jacobson has received research support from Reithera.