TDP-43 nuclear loss in FTD/ALS causes widespread alternative polyadenylation changes

In frontotemporal dementia and amyotrophic lateral sclerosis, the RNA-binding protein TDP-43 is depleted from the nucleus of neurons in the brain and spinal cord. A key function of TDP-43 has emerged as a repressor of cryptic exon inclusion during pre-mRNA splicing, but a role for TDP-43 in other RNA-processing events remains unresolved. Here we show that loss of TDP-43 from neuronal nuclei of human brain and disease-causing mutations in TDP-43 are associated with widespread changes in alternative polyadenylation (APA). Using high-resolution polyadenylation site mapping, we comprehensively defined TDP-43-regulated APA events in human stem cell-derived neurons and found that both the strength and position of TDP-43 binding influence polyA site usage. APA events caused by loss of TDP-43 impact expression of disease-relevant genes (for example, SFPQ, NEFL and TMEM106B). These findings provide evidence that, in addition to cryptic exon inclusion, APA changes are a new facet of TDP-43 pathology.