A seeding based cellular assay of tauopathy

BACKGROUND: Tauopathy is characterized by neurofibrillary tangles composed of insoluble hyperphosphorylated tau protein. Currently, cellular models that mimic neurofibrillary tangles in vitro are lacking. Previous studies indicate that neurofibrillary tangles form via a prion replication mechanism. In the present work, we establish a seeding based cellular model according to the prion hypothesis. RESULTS: We show that cellular soluble tau can be converted to insoluble tau by seeds from the brain lysate of rTg4510 mice or synthetically generated preformed tau fibrils (PFFs). The cellular insoluble tau exhibits classic features of neurofibrillary tangles. Using genetic and pharmacological methods, we demonstrate that inhibition of autophagy increases whereas enhancement of autophagy reduces insoluble tau in our seeding based cellular model. The insoluble tau can be detected and quantified by thioflavin-S staining, thus allowing us to adapt our cellular model to a high-content image-based screening platform. CONCLUSIONS: Our seeding based cellular model reproduces neurofibrillary tangle pathology in vitro and serves as a useful tool for studying tauopathy and identifying tau modulators.