Ex Vivo Gene Therapy Using Patient iPSC-Derived NSCs Reverses Pathology in the Brain of a Homologous Mouse Model

•Sly disease patient fibroblasts converted to iPSCs yield transplantable NSCs•A PiggyBac transposon-based approach corrects the lysosomal enzyme deficiency•Widespread migration of transplanted NSCs occurs in neonates, but not in adults•Reversal of microglial pathology in a zone surrounding corrected grafts

SummaryNeural stem cell (NSC) transplantation is a promising strategy for delivering therapeutic proteins in the brain. We evaluated a complete process of ex vivo gene therapy using human induced pluripotent stem cell (iPSC)-derived NSC transplants in a well-characterized mouse model of a human lysosomal storage disease, Sly disease. Human Sly disease fibroblasts were reprogrammed into iPSCs, differentiated into a stable and expandable population of NSCs, genetically corrected with a transposon vector, and assessed for engraftment in NOD/SCID mice. Following neonatal intraventricular transplantation, the NSCs engraft along the rostrocaudal axis of the CNS primarily within white matter tracts and survive for at least 4 months. Genetically corrected iPSC-NSCs transplanted post-symptomatically into the striatum of adult Sly disease mice reversed neuropathology in a zone surrounding the grafts, while control mock-corrected grafts did not. The results demonstrate the potential for ex vivo gene therapy in the brain using human NSCs from autologous, non-neural tissues.

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