COMBINED GENE/NEURAL STEM CELL BASED APPROACHES FOR GLOBOID CELL AND METACHROMATIC LEUKODYSTROPHIES (GLD and MLD)

Lysosomal storage diseases (LSD) are rare genetic disorders caused by the deficiency of lysosomal enzymes required for important metabolic reactions. Deficiency of arylsufatase A (ARSA) and ß-galactocerebrosidase (GALC) in Metachromatic and Globoid Cell Leukodystrophies (MLD and GLD), respectively, cause a severe lack of myelin, a substance needed for the correct electric activity of the nervous system. The most severe forms of these diseases manifest early after birth with progressive brain damage and are fatal in few years. No cures are available. Newly developed gene therapy (GT) strategies as well cell-based therapies show promising results in animal models, but none of these approaches alone is sufficient to cure the diseases. Among the potential donor cell types for the treatment of LSD, neural stem cells (NSCs) are the most promising. They proliferate as immature cells, but are able to differentiate into mature neurons and glial cells, both in vitro and upon transplantation in the brain. In this project we will explore the efficacy of a novel approach in which gene- and cell-based therapy using NSCs will be combined in order to correct the metabolic defect, restore the enzymatic levels and to prevent/arrest the severe demyelination typical of GLD and MLD animal models. We will first transplant NSCs isolated from healthy mice, since they physiologically produce GALC and ARSA. Moreover, we will isolate NSCs from GLD animal models, in which the disease resembles the human pathology, we will test their functional properties, we will introduce in these cells the missing gene by means of lentiviral (LV)-mediated gene transfer and we will transplant them back in the donor animals. As a further approach, we will exploit the possibility of recruiting endogenous NSCs in the disease animal models (after introducing the missing genes by in vivo LV-mediated gene transfer). Based on our previous results and ongoing work, these approaches will be also tested in combination with the most promising GT strategies in different GLD animal models, in order to target multiple sites of pathology. These experiments will allow to identify NSCs as a renewable source of neural cells for the treatment of leukodystrophies and to validate this approach for the cure of different degenerative CNS pathologies of genetic origin.