Gene therapy of metachromatic leukodystrophy reverses neurological damage and deficits in mice

• Published in: The Journal of clinical investigation Vol. 116; no. 11; pp. 3070 - 3082
• Main Authors: Biffi, Alessandra, Capotondo, Alessia, Fasano, Stefania, del Carro, Ubaldo, Marchesini, Sergio, Azuma, Hisaya, Malaguti, Maria Chiara, Amadio, Stefano, Brambilla, Riccardo, Grompe, Markus, Bordignon, Claudio, Quattrini, Angelo, Naldini, Luigi
• Format: Journal Article
• Language: English
• Published: United States American Society for Clinical Investigation 01.11.2006
• Subjects: Animals; Behavior, Animal; Bioavailability; Biomedical research; Blood-brain barrier; Cell Differentiation; Cerebroside-Sulfatase - deficiency; Cerebroside-Sulfatase - genetics; Cerebroside-Sulfatase - metabolism; Enzymes; Female; Gene therapy; Genes; Genetic Therapy - adverse effects; Hematopoietic stem cells; Hematopoietic Stem Cells - cytology; Hematopoietic Stem Cells - metabolism; Leukodystrophy, Metachromatic - genetics; Leukodystrophy, Metachromatic - metabolism; Leukodystrophy, Metachromatic - pathology; Leukodystrophy, Metachromatic - therapy; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Microglia - metabolism; Microglia - pathology; Nervous system; Nervous system diseases; Neurophysiology - statistics & numerical data; Proteins; Sphingolipidoses; Statistical analysis; Stem cell transplantation; Sulfoglycosphingolipids - metabolism
• ISSN: 0021-9738; 1558-8238
• DOI: 10.1172/jci28873

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.