Specific vulnerability of iPSC-derived motor neurons with TDP-43 gene mutation to oxidative stress

Abstract

Amyotrophic lateral sclerosis (ALS) is a disease that affects motor neurons and has a poor prognosis. We focused on TAR DNA-binding protein 43 kDa (TDP-43), which is a common component of neuronal inclusions in many ALS patients. To analyze the contribution of TDP-43 mutations to ALS in human cells, we first introduced TDP-43 mutations into healthy human iPSCs using CRISPR/Cas9 gene editing technology, induced the differentiation of these cells into motor and sensory neurons, and analyzed factors that are assumed to be altered in or associated with ALS (cell morphology, TDP-43 localization and aggregate formation, cell death, TDP-43 splicing function, etc.). We aimed to clarify the pathological alterations caused solely by TDP-43 mutation, i.e., the changes in human iPSC-derived neurons with TDP-43 mutation compared with those with the same genetic background except TDP-43 mutation. Oxidative stress induced by hydrogen peroxide administration caused the death of TDP-43 mutant-expressing motor neurons but not in sensory neurons, indicating the specific vulnerability of human iPSC-derived motor neurons with TDP-43 mutation to oxidative stress. In our model, we observed aggregate formation in a small fraction of TDP-43 mutant-expressing motor neurons, suggesting that aggregate formation seems to be related to ALS pathology but not the direct cause of cell death. This study provides basic knowledge for elucidating the pathogenesis of ALS and developing treatments for the disease.

Homozygous ALS-linked mutations in TARDBP/TDP-43 lead to hypoactivity and synaptic abnormalities in human iPSC-derived motor neurons

“…These observations are in line with most recent reports of patient-derived and knock-in iPSC models with TARBDP mutations encoding TDP-43 A382T or other ALS variants of TDP-43. 41,52,[64][65][66][67][68][69][70] Some studies, in contrast, found that mutant MNs recapitulate partial aspects of TDP-43 pathology in vitro, 48,53,54,[71][72][73] sometimes reporting enhanced cytoplasmic distribution of TDP-43 (albeit without nuclear depletion), increased levels of insoluble TDP-43 and lower molecular weight species and/or, in few instances, detection of "preinclusion-like aggregates" by immunocytochemistry or electron microscopy.…”

Excessive nucleic acid R-loops induce mitochondria-dependent epithelial cell necroptosis and drive spontaneous intestinal inflammation

“…Similar to our findings, this mutation can result in TDP-43 accumulation in the cytoplasm, TDP-43 nuclear clearance, R-loop accumulation, and compromised mitochondria ( 19 , 41 ), linking R-loop-induced DNA damage to ALS pathogenesis. iPSC-derived motor neurons with TDP-43 A382T mutation are vulnerable to oxidative stress ( 42 ). TDP-43 undergoes nuclear clearance, cytosolic sequestration/aggregation, and fragmentation in motor neurons of nearly 95% of sporadic ALS patients ( 43 , 44 ).…”

The usage and advantages of several common amyotrophic lateral sclerosis animal models

“…Utilizing CRISPR/Cas9 technology, researchers can precisely edit mouse genes, including the TDP-43 gene, to generate more specific transgenic mouse models ( Onda-Ohto et al, 2023 ). This aids in a more in-depth exploration of the specific functions and mechanisms of TDP-43 in ALS.…”