Fig. 2

Isolation and characterization of brain-derived exosomes from CSF. a Exosomes were isolated with a two-step centrifugation. b Representative nanoparticle tracking analysis of the exosome-enriched fraction. Vesicle size and concentration traces were recorded and analyzed over five runs (60s per run) each. c Immunoblots of CSF exosome pellet lysates together with recombinant LRRK2 protein control spiked into HEK293 lysates. Recombinant LRRK2 protein was included at a 1:100,000 (w/v) ratio with HEK293 lysate in LRRK2-Standard 1, and 1:1,000,000 (w/v) ratio in LRRK2-Standard 2. Lysates were also probed with mouse and rabbit secondary antibody alone to confirm the identity of the bands that are due to cross reactive immunoglobulin that co-precipitated with the exosomes (Ig cross-reactive). d Phosphatase treatment of membranes prior to pS1292-LRRK2 detection in CSF exosome lysates. n.s. is not-specific, band of unknown identity. e Comparison of relative LRRK2 expression and pS1292-LRRK2 in purified urinary exosomes, and three representative CSF exosome lysates from the BioFIND cohort. f Representative electron microscopy image of the CSF exosome pellet, scale bar is 50 nm