Background: Progressive Supranuclear Palsy (PSP) is a rare neurodegenerative tauopathy

characterized by the predominant accumulation of the 4-repeat (4R) tau isoform. It is mostly

sporadic and typically begins during the sixth decade of life. Currently, there is no adequate

diagnostic method for PSP and the underlying pathophysiological mechanisms remain poorly

understood. Human olfactory neuroepithelium - derived neural precursor cells (hONE-NPCs)

represent a valuable source of peripheral brain-related cells obtained via a non-invasive

procedure. In addition, exposure to the environmental neurotoxin Annonacin has been

associated with the induction of 4R tau overexpression. Thus, the establishment of in vitro

models using hONE-NPCs from PSP patients and healthy donors, combined with pharmacological

induction of tau pathology, may contribute to the identification of molecular pathways involved

in PSP. The main objective of this study was to establish and characterize these in vitro models

for the study of PSP.

Methods: hONE-NPC cultures were obtained by nasal exfoliation from three PSP patients and

healthy donors without cognitive impairment. Cells were characterized by immunofluorescence

and Western blot. Cell viability assays were performed at different Annonacin concentrations and

exposure times. 4R tau overexpression and hyperphosphorylation were analyzed by Western

blot, along with PSP-associated proteins including PERK, Nrf2, Syntaxin 6, and SLCO1A.

Results: hONE-NPCs derived from PSP patients exhibited altered morphology and differential

expression of stem cell markers (SOX2, Oct3/4, NANOG) as well as neural lineage and

proliferation markers (βIII-tubulin, Nestin, GFAP, Olig1, and Ki67) compared with healthy donor-

derived hONE-NPCs. Pharmacological treatment with Annonacin induced a significant increase in

the 4R tau isoform at a concentration of 2 μM after 96 hours of exposure. Notably, PERK and

Nrf2 expression patterns were different between PSP patient-derived hONE-NPCs and healthy

donors hONE-NPCs with Annonacin-induced 4R tau overexpression.

Conclusion: The non-invasive isolation and maintenance of hONE-NPCs were successfully

standardized in our laboratory. Both hONE-NPCs derived from PSP patients and Annonacin-

induced 4R tau overexpression models demonstrate molecular features relevant to PSP,