Mutant Induced Pluripotent Stem Cell Lines Recapitulate Aspects of TDP-43 Proteinopathies and Reveal Specific Vulnerability

Abstract

Transactive response DNA-binding (TDP-43) protein is the dominant disease protein in amyotrophic lateral sclerosis (ALS) and a sub-group of frontotemporal lobar degeneration (FTLD-TDP). Identification of TARDBP mutations in familial ALS confirms a mechanistic link between misaccumulation of TDP-43 and neurodegeneration and provides an opportunity to study TDP-43 proteinopathies in human neurons generated from patient fibroblasts using induced pluripotent stem cells (iPSC). Here, we report the generation of iPSCs that carry the TDP-43 M337V mutation, and their differentiation into neurons and functional motor neurons. Mutant neurons had elevated levels of soluble and detergent- resistant TDP-43 protein, decreased survival in longitudinal studies, and increased vulnerability to antagonism of the phosphoinositide 3-kinase pathway. We conclude that expression of physiological levels of TDP-43 in human neurons is sufficient to reveal a mutation-specific cell autonomous phenotype and strongly supports this approach for the study of disease mechanisms and for drug screening.