Vimentin network dysregulation mediates neurite deficits in <i>SNCA</i> duplication Parkinson’s patient–derived midbrain neurons

Duplication of the <i>SNCA</i> gene (<i>SNCA</i>^Dupl), linked to elevated levels of α-synuclein (aSyn), is a genetic cause of Parkinson's disease (PD). Our prior work with human-induced pluripotent stem cell (hiPSC)-derived midbrain neurons generated from patients with PD <i>SNCA</i>^Dupl identified neuritic deficits, accompanied by decreased levels of cytoskeletal element β-tubulin-III (bTubIII). To explore mechanisms underlying these effects in <i>SNCA</i>^Dupl neurons, we used CRISPR-Cas9 to generate isogenic control hiPSCs. Isogenic correction of <i>SNCA</i> dosage restored <i>SNCA</i>^Dupl-induced neurite defects and bTubIII levels. Multi-omics analyses revealed <i>SNCA</i>^Dupl-induced alterations in neuronal differentiation, with a notable down-regulation of PAX6. Moreover, <i>SNCA</i>^Dupl induced an up-regulation of vimentin. Further characterization revealed heightened vimentin truncation associated with altered distribution and organization. Similar changes in vimentin levels and truncation were observed in postmortem putamen tissue from patients with sporadic PD. Notably, targeting vimentin with okadaic acid and withaferin A restored bTubIII- and neurite-associated defects, suggesting its potential to prevent aSyn-mediated neuritic degeneration.