Sporadic ALS induced pluripotent stem cell derived neurons reveal hallmarks of TDP-43 loss of function.

Nuclear loss and cytoplasmic buildup of the RNA-binding protein TDP-43 is a hallmark of ALS and related disorders. While studies using artificial TDP-43 depletion in neurons have revealed changes in gene expression and splicing, their relevance to actual patients remained unclear. Induced pluripotent stem cell (iPSC)-derived neurons (iPSNs) from 180 individuals, including controls, C9orf72 ALS/FTD, and sporadic ALS (sALS) patients were used to generate and analyze ~32,500 qRT-PCR data points across 20 genes which identified variable, time-dependent signatures of TDP-43 loss of function in individual lines. Notably, the same changes were also seen in postmortem brain tissue from the same patients, confirming that iPSNs accurately model disease. Inducing damage to the nuclear pore complex, specifically by reducing the nucleoporin POM121 in healthy iPSNs, was enough to replicate the molecular changes associated with ALS/FTD TDP-43 dysfunction. This directly links nuclear pore integrity to TDP-43-related pathology. Encouragingly, repairing nuclear pore injury in sALS iPSNs restored normal gene processing disrupted by TDP-43 loss. This study (1) provides a valuable population-scale resource for studying TDP-43 dysfunction in ALS, (2) confirms that patient-derived iPSNs closely reflect disease processes seen in the brain, and (3) demonstrates that targeting nuclear pore injury may offer a promising therapeutic strategy in ALS.