Temporal Expression of Mutant TDP-43 Correlates with Early Amyotrophic Lateral Sclerosis Phenotype and Motor Weakness

Background Mutant transactive response DNA-binding protein (TDP-43) is closely correlated to the inherited form of amyotrophic lateral sclerosis (ALS). TDP-43 transgenic rats can reproduce the core phenotype of ALS and constitutive expression of TDP-43 caused postnatal death. Objective The study aimed to understand whether neurologic deficiency caused by mutant TDP- 43 is dependent on its temporal expression. Method Transgenic rats were established that express mutant human TDP-43 (M337V substitution) in neurons, then a Tet-off system was used to regulate its expression. Results TDP-43 mutant transgenic rats developed significant weakness after the transgene was activated. Rats with expression of mutant TDP-43 at 30 days showed a more aggressive phenotype. More severe pathological changes in neurogenic atrophy were observed in these rats. Conclusion Temporal expression of mutant TDP-43 in neurons promoted serious phenotype in rats. The dysfunction of TDP-43 had a profound impact on the development of motor neurons and skeletal muscles.