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Mol Ther. 2013 Jul;21(7):1324-34. doi: 10.1038/mt.2013.88. Epub 2013 May 21.

Selective forelimb impairment in rats expressing a pathological TDP-43 25 kDa C-terminal fragment to mimic amyotrophic lateral sclerosis.

Author information

1
Department of Pharmacology, Toxicology, and Neuroscience, Louisiana State University Health Sciences Center, Shreveport, Louisiana, USA.

Abstract

Pathological inclusions containing transactive response DNA-binding protein 43 kDa (TDP-43) are common in several neurodegenerative diseases including amyotrophic lateral sclerosis (ALS). TDP-43 normally localizes predominantly to the nucleus, but during disease progression, it mislocalizes to the cytoplasm. We expressed TDP-43 in rats by an adeno-associated virus (AAV9) gene transfer method that transduces neurons throughout the central nervous system (CNS). To mimic the aberrant cytoplasmic TDP-43 found in disease, we expressed a form of TDP-43 with mutations in the nuclear localization signal sequence (TDP-NLS). The TDP-NLS was detected in both the cytoplasm and the nucleus of transduced neurons. Unlike wild-type TDP-43, expression of TDP-NLS did not induce mortality. However, the TDP-NLS induced disease-relevant motor impairments over 24 weeks. We compared the TDP-NLS to a 25 kDa C-terminal proaggregatory fragment of TDP-43 (TDP-25). The clinical phenotype of forelimb impairment was pronounced with the TDP-25 form, supporting a role of this C-terminal fragment in pathogenesis. The results advance previous rodent models by inducing cytoplasmic expression of TDP-43 in the spinal cord, and the non-lethal phenotype enabled long-term study. Approaching a more relevant disease state in an animal model that more closely mimics underlying mechanisms in human disease could unlock our ability to develop therapeutics.

PMID:
23689600
PMCID:
PMC3702099
DOI:
10.1038/mt.2013.88
[Indexed for MEDLINE]
Free PMC Article

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