Autophagy induction enhances TDP43 turnover and survival in neuronal ALS models

Inclusions containing TDP43 are linked to pathologies in several neurodegenerative diseases such as ALS and FTD. Pathogenic TDP43 mutations are now found to shorten the protein's half-life in individual neurons. Stimulating autophagy with inhibitors improves TDP43 clearance and localization. Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) have distinct clinical features but a common pathology—cytoplasmic inclusions rich in transactive response element DNA-binding protein of 43 kDa (TDP43). Rare TDP43 mutations cause ALS or FTD, but abnormal TDP43 levels and localization may cause disease even if TDP43 lacks a mutation. Here we show that individual neurons vary in their ability to clear TDP43 and are exquisitely sensitive to TDP43 levels. To measure TDP43 clearance, we developed and validated a single-cell optical method that overcomes the confounding effects of aggregation and toxicity and discovered that pathogenic mutations shorten TDP43 half-life. New compounds that stimulate autophagy improved TDP43 clearance and localization and enhanced survival in primary murine neurons and in human stem cell–derived neurons and astrocytes harboring mutant TDP43. These findings indicate that the levels and localization of TDP43 critically determine neurotoxicity and show that autophagy induction mitigates neurodegeneration by acting directly on TDP43 clearance.