ASO-enhancement ofTARDBPexitron splicing mitigates TDP-43 proteinopathies

Abstract

AbstractAmyotrophic lateral sclerosis and frontotemporal lobar degeneration are fatal neurodegenerative diseases characterized by pathological aggregation and nuclear functional loss of TDP-431,2. Current therapies inadequately address this core pathology3,4, necessitating innovative approaches that target aggregation while preserving TDP-43’s essential functions. Here we demonstrate that enhancing the splicing of theTARDBPexitron—a cryptic intron encoding the aggregation-prone intrinsically disordered region (IDR) of TDP-435,6— effectively mitigates TDP-43 pathology. This exitron splicing event, directly regulated by nuclear TDP-437–9, suppresses the expression of IDR-containing TDP-43 isoforms and generates IDR-spliced-out TDP-43 isoforms7,9,10(which we term “IDRsTDP”). Our findings reveal that IDRsTDP, known to heterodimerize with full-length TDP-4310, inhibits TDP-43 aggregation by suppressing IDR-mediated clustering and enhances TDP-43 clearance via chaperone-mediated autophagy. In disease states, however, impaired nuclear TDP-43 function disrupts exitron splicing, leading to increased levels of IDR-containing TDP-439,11and reduced levels of IDRsTDP, exacerbating aggregation and nuclear dysfunction6,12–17. By identifying HNRNPA1 and HNRNPC as key repressors ofTARDBPexitron splicing, we designed antisense oligonucleotides (ASOs) to block their binding and restore splicing. These ASOs suppressed TDP-43 pathology and neurodegeneration in both neuronal cell models with impaired nuclear transport and a mouse model of proteasome dysfunction-induced TDP-43 proteinopathy. Our strategy, by rescuing the impaired autoregulatory pathway, inhibits the pathological cycle of TDP-43 aggregation and nuclear dysfunction, offering a promising avenue for treating these currently intractable neurodegenerative diseases.