In fact, in vitro and in vivo models showed that pathological forms of extracellular tau are taken up by cells and can induce intracellular tau aggregates [37-39 The propagation properties of tau can depend on its isoforms, its state of aggregation, and post-translational modifications, which can also determine the respective tauopathy [40 The concept remains controversial but has attracted attention as a potential therapeutic target for stopping the progression of tauopathies since reducing extracellular tau could slow the spread of the tau pathology. Here, MAPT is linked to tauopathy.