Delcambre, S. | bioRxiv Science

bioRxiv2026

SNCA triplication shapes neuronal extracellular vesicle biology and promotes microglial activation in patient-derived iPSC-based models of Parkinson's disease

Extracellular vesicles (EVs) are emerging as key mediators of intercellular communication and potential biomarkers in Parkinson's disease (PD), yet how disease-causing genetic alterations shape neuronal EV biology remains incompletely understood. Here, we used PD-patient iPSC-derived midbrain dopaminergic neurons (mDANs) harboring SNCA triplication (SNCA-4x), gene-corrected controls (SNCA-GC), and SNCA knockout (SNCA-KO) to investigate the impact of -synuclein overexpression on neuronal-enriched EV (nEV) biology and neuron to microglia communication. SNCA-4x mDANs exhibited marked transcriptional alterations in pathways related to vesicle trafficking and extracellular matrix organization. Using an optimized isolation workflow, SNCA-4x neurons released significantly more and smaller nEVs enriched in -synuclein, mitochondrial DNA (mtDNA), and PARK7/DJ-1 mRNA, while displaying reduced acetylcholinesterase activity. Functionally, SNCA-4x-derived nEVs were taken up more efficiently by isogenic control iPSC-derived microglia than SNCA-GC nEVs and induced stronger pro-inflammatory activation than both SNCA-GC nEVs and untreated microglia, characterized by altered microglial morphology and increased TNF- and IL-1{beta}, consistent with damage-associated molecular pattern (DAMP)-mediated signaling. Together, these findings demonstrate that SNCA-4x reshapes the properties and molecular cargo of nEVs, enhancing their capacity to trigger microglial activation, and identify EV-associated -synuclein, mtDNA, and PARK7 mRNA as candidate mechanistic and biomarker features in PD.

neuroscience↗

bioRxiv2024

DJ-1 mediates regulation of metabolism and immune response in Parkinsons disease astrocytes and Glioblastoma cells

An inverse correlation for the expression of Parkinsons disease (PD)- and cancer-associated genes has been previously reported. Genes that are upregulated in cancer are frequently downregulated in PD and vice versa. PARK7, encoding DJ-1, was initially identified as an oncogene, but loss of DJ-1 causes early-onset PD. However, it remains elusive how differential DJ-1 levels contribute to opposite cell fates in cancer and PD. Here, we demonstrate specific effects of differential DJ-1 protein levels on the energy metabolism and cell growth in patient-derived cellular models of PD and glioblastoma (GBM) cell lines. Impaired energy metabolism was associated with an increased immune response upon IL-1{beta} stimulation and increased apoptosis and decreased cell growth in models of PD, whereas in GBM cells increased metabolic activity translated into a reduced immune response and increased cell growth. Furthermore, we found decreased glutathione (GSH) synthesis and therefore increased levels of reactive oxygen species (ROS) and oxidized glutathione (GSSG) in models of DJ-1 deficiency and decreased ROS levels in GBM cell lines. Thus, the mechanism by which DJ-1 modulates these phenotypes is the same in both diseases. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=84 SRC="FIGDIR/small/621212v1_ufig1.gif" ALT="Figure 1"> View larger version (38K): org.highwire.dtl.DTLVardef@4eccb4org.highwire.dtl.DTLVardef@161669corg.highwire.dtl.DTLVardef@197bfc3org.highwire.dtl.DTLVardef@1aecb36_HPS_FORMAT_FIGEXP M_FIG C_FIG DJ-1 levels modulate GSSG/GSH ratio and ROS levels, which results in divergent effects on cell growth and immune response in DJ-1-dependent glial pathologies in glioblastoma and PD. In models of PD, DJ-1 level dependent phenotypes can be rescued by antioxidant treatment that reduces the GSSG/GSH ratio and ROS levels.

neuroscience↗