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Itakura, E.

Publications and source records attributed to Itakura, E..

2 recordsLinked to original sources

Identification of novel autophagy inducers by accelerating lysosomal clustering against Parkinson's disease

Autophagy-lysosome pathway plays an indispensable role in the intracellular protein quality control system, degrading abnormal organelles and proteins. Among these proteins is -Synuclein (Syn), which is associated with the pathogenesis of Parkinsons disease (PD). However, the activation of this lysosome-dependent degradation strategy is restricted by enzyme complementation. In this study, we focused on the phase of autophagosome-lysosome fusion around the microtubule organizing center (MTOC) that leads to Syn degradation. Through high-throughput chemical screening, we identified six clinically available drugs that enhance autophagy and can accumulate lysosomes around the MTOC from approximately 1,200 drugs screened. We further demonstrated that these compounds induce lysosomal clustering through a JIP4-TRPML1-dependent mechanism, which is associated with autophagy induction. Among these, the lysosomal clustering compound albendazole was observed to promote the autophagy-dependent degradation of Triton-X-insoluble proteasome inhibitor-induced aggregates (p62). In a cellular PD model, albendazole boosted the degradation of insoluble Syn, an effect that was reversed upon the addition of bafilomycin A1. Our results suggest that lysosomal clustering can facilitate the breakdown of protein aggregates. Therefore, compounds that promote lysosomal clustering may offer a promising therapeutic strategy against neurodegenerative diseases characterized by the presence of aggregate-prone proteins.

cell biology↗

Fluctuation of lysosomal protein degradation in neural stem cells of postnatal mouse brain

Lysosomes are intracellular organelles responsible for degrading diverse macromolecules delivered from several pathways, such as the endo-lysosomal and autophagic pathways. Recent reports have suggested that lysosomes are essential in regulating neural stem cells in developing, adult, and aged brains. However, the activity of these lysosomes has not yet been monitored in these brain tissues. Here, we report a new probe to measure lysosomal protein degradation in brain tissue by immunostaining. Our results demonstrate the fluctuation of lysosomal protein degradation in neural stem cells depending on age and brain disorder. Neural stem cells increase lysosomal activity during hippocampal development in the dentate gyrus, but aging and aging-related disease reduces their activity. In addition, physical exercise increases lysosomal activity in neural stem cells and astrocytes. We hypothesize three different stages of lysosomal activity: the increase in development, the stable state for the adult stage, and the reduction by damages with age or disease.

neuroscience↗