Ribosome-associated pathological TDP-43 alters the expression of multiple mRNAs in the monkey brain.

Cytoplasmic accumulation of TDP-43 is a pathological hallmark of amyotrophic lateral sclerosis (ALS) and other neurodegenerative diseases. While current studies have primarily focused on gene regulation mediated by full-length nuclear TDP-43, the potential effects of cytoplasmic TDP-43 fragments remain less explored. Our previous findings demonstrated that primate-specific cleavage of TDP-43 contributes to its cytoplasmic localization, prompting further investigation into its pathological effects. In the cynomolgus monkey brain, we observed that mutant or truncated TDP-43 was transported onto the ribosome organelle. Ribosome-associated transcriptomic analysis revealed dysregulation of apoptosis- and lysosome-related genes, indicating that cytoplasmic TDP-43 induces neurotoxicity by binding to ribosomes and disrupting mRNA expression. These findings provide mechanistic insights into the gain-of-function effects of pathological TDP-43.