title: Gene therapy of metachromatic leukodystrophy reverses neurological damage and deficits in mice.
abstract: Metachromatic leukodystrophy (MLD) is a demyelinating lysosomal storage disorder for which new treatments are urgently needed. We previously showed that transplantation of gene-corrected hematopoietic stem progenitor cells (HSPCs) in presymptomatic myeloablated MLD mice prevented disease manifestations. Here we show that HSC gene therapy can reverse neurological deficits and neuropathological damage in affected mice, thus correcting an overt neurological disease. The efficacy of gene therapy was dependent on and proportional to arylsulfatase A (ARSA) overexpression in the microglia progeny of transplanted HSPCs. We demonstrate a widespread enzyme distribution from these cells through the CNS and a robust cross-correction of neurons and glia in vivo. Conversely, a peripheral source of enzyme, established by transplanting ARSA-overexpressing hepatocytes from transgenic donors, failed to effectively deliver the enzyme to the CNS. These results indicate that the recruitment of gene-modified, enzyme-overexpressing microglia makes the enzyme bioavailable to the brain and makes therapeutic efficacy and disease correction attainable. Overall, our data provide a strong rationale for implementing HSPC gene therapy in MLD patients.
authors.affiliation: San Raffaele Telethon Institute for Gene Therapy, Vita-Salute San Raffaele University, Milan, Italy. biffi.alessandra@hsr.it
authors.forename: Alessandra
authors.initials: A
authors.lastname: Biffi
authors.forename: Alessia
authors.initials: A
authors.lastname: Capotondo
authors.forename: Stefania
authors.initials: S
authors.lastname: Fasano
authors.forename: Ubaldo
authors.initials: U
authors.lastname: del Carro
authors.forename: Sergio
authors.initials: S
authors.lastname: Marchesini
authors.forename: Hisaya
authors.initials: H
authors.lastname: Azuma
authors.forename: Maria Chiara
authors.initials: MC
authors.lastname: Malaguti
authors.forename: Stefano
authors.initials: S
authors.lastname: Amadio
authors.forename: Riccardo
authors.initials: R
authors.lastname: Brambilla
authors.forename: Markus
authors.initials: M
authors.lastname: Grompe
authors.forename: Claudio
authors.initials: C
authors.lastname: Bordignon
authors.forename: Angelo
authors.initials: A
authors.lastname: Quattrini
authors.forename: Luigi
authors.initials: L
authors.lastname: Naldini
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D002454:Cell Differentiation; D002553:Cerebroside-Sulfatase / Q000172:deficiency / Q000235:genetics / Q000378:metabolism; D005260:Female; D015316:Genetic Therapy / Q000009:adverse effects*; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000378:metabolism; D007966:Leukodystrophy, Metachromatic / Q000235:genetics* / Q000378:metabolism / Q000473:pathology / Q000628:therapy*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D017628:Microglia / Q000378:metabolism / Q000473:pathology; D009482:Neurophysiology / Q000706:statistics & numerical data; D013433:Sulfoglycosphingolipids / Q000378:metabolism
chemical_list: D013433:Sulfoglycosphingolipids; D002553:Cerebroside-Sulfatase