APP and neurodegenerative disease: TNTs have been proposed to play a key role in neurodegenerative diseases and are involved in the spread of aggregated proteins such as tau, APP, and huntingtin by an intracellular pathway instead of a soluble-mediated mechanism (Gousset and Zurzolo, 2009; Abounit et al., 2016; Grudina et al., 2019; Mittal et al., 2019).